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Sample records for electron microscopy x-ray

  1. Bulk sensitive hard x-ray photoemission electron microscopy

    SciTech Connect

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

    2014-11-15

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

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

    SciTech Connect

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

    1988-11-01

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

  3. 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.

  4. SCANNING ELECTRON MICROSCOPY/X-RAY FLUORESCENCE CHARACTERIZATION OF POST-ABATEMENT DUST

    EPA Science Inventory

    Scanning electron microscopy (SEM) and laboratory X-ray fluorescence (XRF) were used to characterize post-abatement dust collected with a HEPA filtered vacuum. hree size fractions of resuspended dust (0-30 pm, 2.5-15 pm, and <2.5 pm) were collected on teflon filters and analyzed ...

  5. X-ray structure determination using low-resolution electron microscopy maps for molecular replacement

    SciTech Connect

    Jackson, Ryan N.; McCoy, Airlie J.; Terwilliger, Thomas C.; Read, Randy J.; Wiedenheft, Blake

    2015-07-30

    Structures of multi-subunit macromolecular machines are primarily determined by either electron microscopy (EM) or X-ray crystallography. In many cases, a structure for a complex can be obtained at low resolution (at a coarse level of detail) with EM and at higher resolution (with finer detail) by X-ray crystallography. The integration of these two structural techniques is becoming increasingly important for generating atomic models of macromolecular complexes. A low-resolution EM image can be a powerful tool for obtaining the "phase" information that is missing from an X-ray crystallography experiment, however integration of EM and X-ray diffraction data has been technically challenging. Here we show a step-by-step protocol that explains how low-resolution EM maps can be placed in the crystallographic unit cell by molecular replacement, and how initial phases computed from the placed EM density are extended to high resolution by averaging maps over non-crystallographic symmetry. As the resolution gap between EM and Xray crystallography continues to narrow, the use of EM maps to help with X-ray crystal structure determination, as described in this protocol, will become increasingly effective.

  6. X-ray structure determination using low-resolution electron microscopy maps for molecular replacement

    DOE PAGESBeta

    Jackson, Ryan N.; McCoy, Airlie J.; Terwilliger, Thomas C.; Read, Randy J.; Wiedenheft, Blake

    2015-07-30

    Structures of multi-subunit macromolecular machines are primarily determined by either electron microscopy (EM) or X-ray crystallography. In many cases, a structure for a complex can be obtained at low resolution (at a coarse level of detail) with EM and at higher resolution (with finer detail) by X-ray crystallography. The integration of these two structural techniques is becoming increasingly important for generating atomic models of macromolecular complexes. A low-resolution EM image can be a powerful tool for obtaining the "phase" information that is missing from an X-ray crystallography experiment, however integration of EM and X-ray diffraction data has been technically challenging.more » Here we show a step-by-step protocol that explains how low-resolution EM maps can be placed in the crystallographic unit cell by molecular replacement, and how initial phases computed from the placed EM density are extended to high resolution by averaging maps over non-crystallographic symmetry. As the resolution gap between EM and Xray crystallography continues to narrow, the use of EM maps to help with X-ray crystal structure determination, as described in this protocol, will become increasingly effective.« less

  7. X-ray photoemission electron microscopy, a tool for the investigation of complex magnetic structures.

    SciTech Connect

    Scholl, Andreas; Ohldag, Hendrik; Nolting, Frithjof; Stohr, Joachim; Padmore, Howard A.

    2001-08-30

    X-ray Photoemission Electron Microscopy unites the chemical specificity and magnetic sensitivity of soft x-ray absorption techniques with the high spatial resolution of electron microscopy. The discussed instrument possesses a spatial resolution of better than 50 nm and is located at a bending magnet beamline at the Advanced Light Source, providing linearly and circularly polarized radiation between 250 and 1300 eV. We will present examples which demonstrate the power of this technique applied to problems in the field of thin film magnetism. The chemical and elemental specificity is of particular importance for the study of magnetic exchange coupling because it allows separating the signal of the different layers and interfaces in complex multi-layered structures.

  8. Energy-filtered X-ray photoemission electron microscopy and its applications to surface and organic materials

    NASA Astrophysics Data System (ADS)

    Tsutsumi, Tetsuya; Miyamoto, Takeshi; Niimi, Hironobu; Kitajima, Yoshinori; Sakai, Yuji; Kato, Makoto; Naito, Toshio; Asakura, Kiyotaka

    2007-10-01

    Energy-filtered X-ray photoemission electron microscopy (EXPEEM) is a new surface chemical imaging method that combines X-ray photoelectron spectroscopy (XPS) and photoemission electron microscopy (PEEM). We have developed a collinear type EXPEEM system using a Wien-filter-type electron energy analyzer. The collinear arrangement has the advantage of carrying out an easy alignment of the electron optical axis. We have measured EXPEEM images, μ-X-ray absorption near edge structure (μ-XANES) and μ-XPS of Au on Ta and Ag(DM) 2. We discuss the advantage of EXPEEM and future applications to organic devices.

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

    SciTech Connect

    Forslind, B.

    1984-01-01

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

  10. X-ray photoemission electron microscopy for the study of semiconductor materials

    SciTech Connect

    Anders, S.; Stammler, T.; Padmore, H.; Terminello, L.J.; Jankowski, A.F.; Stohr, J.; Diaz, J.; Cossy-Gantner, A.

    1998-03-01

    Photoemission Electron Microscopy (PEEM) using X-rays is a novel combination of two established materials analysis techniques--PEEM using UV light, and Near Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy. This combination allows the study of elemental composition and bonding structure of the sample by NEXAFS spectroscopy with a high spatial resolution given by the microscope. A simple, two lens, 10 kV operation voltage PEEM has been used at the Stanford Synchrotron Radiation Laboratory and at the Advanced Light Source (ALS) in Berkeley to study various problems including materials of interest for the semiconductor industry. In the present paper the authors give a short overview over the method and the instrument which was used, and describe in detail a number of applications. These applications include the study of the different phases of titanium disilicide, various phases of boron nitride, and the analysis of small particles. A brief outlook is given on possible new fields of application of the PEEM technique, and the development of new PEEM instruments.

  11. Applications of scanning electron microscopy and X-ray microanalysis in inner ear pathology

    SciTech Connect

    Anniko, M.; Lim, D.J.; Sobin, A.; Wroblewski, R.

    1985-01-01

    Surface pathology of inner ear structures so far described in detail concern cochlear and vestibular hair cells and the stria vascularis. In man, surgical intervention into the inner ear is very uncommon and when performed is in general with the primary objective of destroying the diseased peripheral end organs. The vast majority of inner ear tissue available for use with scanning electron microscopy (SEM) is therefore obtained from animals. The present paper reviews the progression of surface pathology caused by aminoglycoside antibiotics, acoustic overstimulation and in a guinea pig strain with genetic inner ear disease. The primary site of onset of surface pathology differs, depending on the underlying cause. Advanced surface pathology shows a similar type of morphological degeneration independent of cause. The combination of SEM and energy dispersive X-ray microanalysis (XRMA) of inner ear pathology has as yet been reported in only three studies, all concerning inner ear fluids or otoconia.

  12. Study of hard disk and slider surfaces using X-ray photoemission electron microscopy and near-edge X-ray absorption fine structure spectroscopy

    SciTech Connect

    Anders, S.; Stammler, T.; Bhatia, C.S.; Fong, W.; Chen, C.Y.; Bogy, D.B.

    1998-04-01

    X-ray Photo Emission Electron Microscopy (X-PEEM) and Near Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy were applied to study the properties of amorphous hard carbon overcoats on disks and sliders, and the properties of the lubricant. The modification of lubricants after performing thermal desorption studies was measured by NEXAFS, and the results are compared to the thermal desorption data. The study of lubricant degradation in wear tracks is described. Sliders were investigated before and after wear test, and the modification of the slider coating as well as the transfer of lubricant to the slider was studied. The studies show that the lubricant is altered chemically during the wear. Fluorine is removed and carboxyl groups are formed.

  13. X-ray absorption spectroscopy by full-field X-ray microscopy of a thin graphite flake: Imaging and electronic structure via the carbon K-edge

    PubMed Central

    Hitchock, Adam P; Ke, Xiaoxing; Van Tendeloo, Gustaaf; Ewels, Chris P; Guttmann, Peter

    2012-01-01

    Summary We demonstrate that near-edge X-ray-absorption fine-structure spectra combined with full-field transmission X-ray microscopy can be used to study the electronic structure of graphite flakes consisting of a few graphene layers. The flake was produced by exfoliation using sodium cholate and then isolated by means of density-gradient ultracentrifugation. An image sequence around the carbon K-edge, analyzed by using reference spectra for the in-plane and out-of-plane regions of the sample, is used to map and spectrally characterize the flat and folded regions of the flake. Additional spectral features in both π and σ regions are observed, which may be related to the presence of topological defects. Doping by metal impurities that were present in the original exfoliated graphite is indicated by the presence of a pre-edge signal at 284.2 eV. PMID:23016137

  14. Comparison of SOFC Cathode Microstructure Quantified using X-ray Nanotomography and Focused Ioni Beam-scanning Electron Microscopy

    SciTech Connect

    G Nelson; W Harris; J Lombardo; J Izzo Jr.; W Chiu; P Tanasini; M Cantoni; J Van herle; C Comninellis; et al.

    2011-12-31

    X-ray nanotomography and focused ion beam scanning electron microscopy (FIB-SEM) have been applied to investigate the complex 3D microstructure of solid oxide fuel cell (SOFC) electrodes at spatial resolutions of 45 nm and below. The application of near edge differential absorption for x-ray nanotomography and energy selected backscatter detection for FIB-SEM enable elemental mapping within the microstructure. Using these methods, non-destructive 3D x-ray imaging and FIB-SEM serial sectioning have been applied to compare three-dimensional elemental mapping of the LSM, YSZ, and pore phases in the SOFC cathode microstructure. The microstructural characterization of an SOFC cathode is reported based on these measurements. The results presented demonstrate the viability of x-ray nanotomography as a quantitative characterization technique and provide key insights into the SOFC cathode microstructure.

  15. Comparison of SOFC Cathode Microstructure Quantified using X-ray Nanotomography and Focused Ion Beam - Scanning Electron Microscopy

    SciTech Connect

    Nelson, George J.; Harris, William H.; Lombardo, Jeffrey J.; Izzo, Jr., John R.; Chiu, W. K. S.; Tanasini, Pietro; Cantoni, Marco; Van herle, Jan; Comninellis, Christos; Andrews, Joy C.; Liu, Yijin; Pianetta, Piero; Chu, Yong

    2011-03-24

    X-ray nanotomography and focused ion beam scanning electron microscopy (FIB-SEM) have been applied to investigate the complex 3D microstructure of solid oxide fuel cell (SOFC) electrodes at spatial resolutions of 45 nm and below. The application of near edge differential absorption for x-ray nanotomography and energy selected backscatter detection for FIB–SEM enable elemental mapping within the microstructure. Using these methods, non-destructive 3D x-ray imaging and FIB–SEM serial sectioning have been applied to compare three-dimensional elemental mapping of the LSM, YSZ, and pore phases in the SOFC cathode microstructure. The microstructural characterization of an SOFC cathode is reported based on these measurements. The results presented demonstrate the viability of x-ray nanotomography as a quantitative characterization technique and provide key insights into the SOFC cathode microstructure.

  16. Clinical applications of scanning electron microscopy and energy dispersive X-ray analysis in dermatology--an up-date

    SciTech Connect

    Forslind, B.

    1988-06-01

    Dermatological papers comprising scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis data published 1983 through 1986 in international journals are reviewed, as an update to our 1984 paper on Clinical applications of scanning electron microscopy and X-ray microanalysis in dermatology. The present paper not only deals with a review of recent publications in this area but also presents the application of microincineration to hair and cryosectioned freeze-dried skin specimens. Examples of the increased contrast obtained in hair cross sections are presented and a discussion on the feasibility of microincineration at analysis of hair and skin cross sections is given. Particle probe analysis (EDX: energy dispersive X-ray analysis and PMP: proton microprobe analysis) as applied to hair and skin samples are presented with stress put on the proton probe analysis. The complementarity of EDX and PMP is demonstrated and future applications are suggested. 75 references.

  17. Probing the electronic structure of graphene sheets with various thicknesses by scanning transmission X-ray microscopy

    SciTech Connect

    Bai, Lili; Liu, Jinyin; Zhao, Guanqi; Gao, Jing; Sun, Xuhui E-mail: jzhong@suda.edu.cn; Zhong, Jun E-mail: jzhong@suda.edu.cn

    2013-12-16

    The electronic structure of an aggregation of graphene sheets with various thicknesses was probed by scanning transmission X-ray microscopy. A uniform oxidation of the graphene sheets in the flat area was observed regardless of the thickness, while in the folded area the result could be strongly affected by the geometry. Moreover, thick parts of the aggregation showed strong angle-dependence to the incident X-ray, while thin parts showed less angle-dependence, which might be related to the surface wrinkles and ripples. The electronic structure differences due to the geometry and thickness suggest a complicated situation in the aggregation of graphene sheets.

  18. Electron microscopy and x-ray diffraction evidence for two Z-band structural states.

    PubMed

    Perz-Edwards, Robert J; Reedy, Michael K

    2011-08-01

    In vertebrate muscles, Z-bands connect adjacent sarcomeres, incorporate several cell signaling proteins, and may act as strain sensors. Previous electron microscopy (EM) showed Z-bands reversibly switch between a relaxed, "small-square" structure, and an active, "basketweave" structure, but the mechanism of this transition is unknown. Here, we found the ratio of small-square to basketweave in relaxed rabbit psoas muscle varied with temperature, osmotic pressure, or ionic strength, independent of activation. By EM, the A-band and both Z-band lattice spacings varied with temperature and pressure, not ionic strength; however, the basketweave spacing was consistently 10% larger than small-square. We next sought evidence for the two Z-band structures in unfixed muscles using x-ray diffraction, which indicated two Z-reflections whose intensity ratios and spacings correspond closely to the EM measurements for small-square and basketweave if the EM spacings are adjusted for 20% shrinkage due to EM processing. We conclude that the two Z-reflections arise from the small-square and basketweave forms of the Z-band as seen by EM. Regarding the mechanism of transition during activation, the effects of Ca(2+) in the presence of force inhibitors suggested that the interconversion of Z-band forms was correlated with tropomyosin movement on actin. PMID:21806939

  19. Architectural plasticity of AMPK revealed by electron microscopy and X-ray crystallography

    PubMed Central

    Ouyang, Yan; Zhu, Li; Li, Yifang; Guo, Miaomiao; Liu, Yang; Cheng, Jin; Zhao, Jing; Wu, Yi

    2016-01-01

    Mammalian AMP-activated protein kinase (AMPK) acts as an important sensor of cellular energy homeostasis related with AMP/ADP to ATP ratio. The overall architecture of AMPK has been determined in either homotrimer or monomer form by electron microscopy (EM) and X-ray crystallography successively. Accordingly proposed models have consistently revealed a key role of the α subunit linker in sensing adenosine nucleoside binding on the γ subunit and mediating allosteric regulation of kinase domain (KD) activity, whereas there are vital differences in orienting N-terminus of α subunit and locating carbohydrate-binding module (CBM) of β subunit. Given that Mg2+, an indispensable cofactor of AMPK was present in the EM sample preparation buffer however absent when forming crystals, here we carried out further reconstructions without Mg2+ to expectably inspect if this ion may contribute to this difference. However, no essential alteration has been found in this study compared to our early work. Further analyses indicate that the intra-molecular movement of the KD and CBM are most likely due to the flexible linkage of the disordered linkers with the rest portion as well as a contribution from the plasticity in the inter-molecular assembly mode, which might ulteriorly reveal an architectural complication of AMPK. PMID:27063142

  20. Architectural plasticity of AMPK revealed by electron microscopy and X-ray crystallography.

    PubMed

    Ouyang, Yan; Zhu, Li; Li, Yifang; Guo, Miaomiao; Liu, Yang; Cheng, Jin; Zhao, Jing; Wu, Yi

    2016-01-01

    Mammalian AMP-activated protein kinase (AMPK) acts as an important sensor of cellular energy homeostasis related with AMP/ADP to ATP ratio. The overall architecture of AMPK has been determined in either homotrimer or monomer form by electron microscopy (EM) and X-ray crystallography successively. Accordingly proposed models have consistently revealed a key role of the α subunit linker in sensing adenosine nucleoside binding on the γ subunit and mediating allosteric regulation of kinase domain (KD) activity, whereas there are vital differences in orienting N-terminus of α subunit and locating carbohydrate-binding module (CBM) of β subunit. Given that Mg(2+), an indispensable cofactor of AMPK was present in the EM sample preparation buffer however absent when forming crystals, here we carried out further reconstructions without Mg(2+) to expectably inspect if this ion may contribute to this difference. However, no essential alteration has been found in this study compared to our early work. Further analyses indicate that the intra-molecular movement of the KD and CBM are most likely due to the flexible linkage of the disordered linkers with the rest portion as well as a contribution from the plasticity in the inter-molecular assembly mode, which might ulteriorly reveal an architectural complication of AMPK. PMID:27063142

  1. Barriers to Quantitative Electron Probe X-Ray Microanalysis for Low Voltage Scanning Electron Microscopy

    PubMed Central

    Newbury, Dale E.

    2002-01-01

    Low voltage x-ray microanalysis, defined as being performed with an incident beam energy ≤5 keV, can achieve spatial resolution, laterally and in depth, of 100 nm or less, depending on the exact selection of beam energy and the composition of the target. The shallow depth of beam penetration, with the consequent short path length for x-ray absorption, and the low overvoltage, the ratio of beam energy to the critical ionization energy, both contribute to minimizing the matrix effects in quantitative x-ray microanalysis when the unknown is compared to pure element standards. The low beam energy restricts the energy of the atomic shells that can be excited, forcing the analyst to choose unfamiliar shells/characteristic peaks. The low photon energy shells are subject to low fluorescence yield, so that the peak-to-continuum background is reduced, severely limiting detectability. The limited resolution of semiconductor energy dispersive spectrometry results in frequent peak interference situations and further exacerbates detection limits. Future improvements to the x-ray spectrometry limitations are possible with x-ray optics-augmented wavelength dispersive spectrometry and microcalorimeter energy dispersive spectrometry.

  2. SCANNING ELECTRON MICROSCOPY AND X-RAY DIFFRACTION ANALYSIS OF TANK 18 SAMPLES

    SciTech Connect

    Hay, M.; O'Rourke, P.; Ajo, H.

    2012-03-08

    The F-Area Tank Farm (FTF) Performance Assessment (PA) utilizes waste speciation in the waste release model used in the FTF fate and transport modeling. The waste release modeling associated with the residual plutonium in Tank 18 has been identified as a primary contributor to the Tank 18 dose uncertainty. In order to reduce the uncertainty related to plutonium in Tank 18, a better understanding of the plutonium speciation in the Tank 18 waste (including the oxidation state and stoichiometry) is desired. Savannah River National Laboratory (SRNL) utilized Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD) to analyze Tank 18 samples to provide information on the speciation of plutonium in the waste material. XRD analysis of the Tank 18 samples did not identify any plutonium mineral phases in the samples. These indicates the crystalline mineral phases of plutonium are below the detection limits of the XRD method or that the plutonium phase(s) lack long range order and are present as amorphous or microcrystalline solids. SEM analysis of the Tank 18 samples did locate particles containing plutonium. The plutonium was found as small particles, usually <1 {micro}m but ranging up to several micrometers in diameter, associated with particles of an iron matrix and at low concentration in other elemental matrices. This suggests the plutonium has an affinity for the iron matrix. Qualitatively, the particles of plutonium found in the SEM analysis do not appear to account for all of the plutonium in the sample based on concentrations determined from the chemical analysis of the Tank 18 samples. This suggests that plutonium is also distributed throughout the solids in low concentrations.

  3. Probing Heterogeneous Chemistry of Individual Atmospheric Particles Using Scanning Electron Microscopy and Energy-Dispersive X-ray Analysis

    SciTech Connect

    Krueger, Brenda J.; Grassian, Vicki H.; Iedema, Martin J.; Cowin, James P.; Laskin, Alexander

    2003-10-01

    In this paper, we demonstrate the utility of single-particle analysis to investigate the chemistry of isolated, individual particles of atmospheric relevance such as NaCl, sea salt, CaCO3, and SiO2. A variety of state-of-th-art scanning electron microscopy techniques, including environmental scanning electon microscopy and computer-controlled scanning electron microscopy/energy-dispersive X-ray analysis, were utilized for monitoring and quantifying phase transitions of individual particles, morphology, and compositional changes of individual particles as they react with nitric acid.

  4. Small angle X-ray scattering and transmission electron microscopy study of the Lactobacillus brevis S-layer protein

    NASA Astrophysics Data System (ADS)

    Jääskeläinen, Pentti; Engelhardt, Peter; Hynönen, Ulla; Torkkeli, Mika; Palva, Airi; Serimaa, Ritva

    2010-10-01

    The structure of self-assembly domain containing recombinant truncation mutants of Lactobacillus brevis surface layer protein SlpA in aqueous solution was studied using small-angle X-ray scattering and transmission electron microscopy. The proteins were found out to interact with each other forming stable globular oligomers of about 10 monomers. The maximum diameter of the oligomers varied between 75 Å and 435 Å.

  5. An undulator based soft x-ray source for microscopy on the Duke electron storage ring

    NASA Astrophysics Data System (ADS)

    Johnson, Lewis Elgin

    1998-09-01

    This dissertation describes the design, development, and installation of an undulator-based soft x-ray source on the Duke Free Electron Laser laboratory electron storage ring. Insertion device and soft x-ray beamline physics and technology are all discussed in detail. The Duke/NIST undulator is a 3.64-m long hybrid design constructed by the Brobeck Division of Maxwell Laboratories. Originally built for an FEL project at the National Institute of Standards and Technology, the undulator was acquired by Duke in 1992 for use as a soft x-ray source for the FEL laboratory. Initial Hall probe measurements on the magnetic field distribution of the undulator revealed field errors of more than 0.80%. Initial phase errors for the device were more than 11 degrees. Through a series of in situ and off-line measurements and modifications we have re-tuned the magnet field structure of the device to produce strong spectral characteristics through the 5th harmonic. A low operating K has served to reduce the effects of magnetic field errors on the harmonic spectral content. Although rms field errors remained at 0.75%, we succeeded in reducing phase errors to less than 5 degrees. Using trajectory simulations from magnetic field data, we have computed the spectral output given the interaction of the Duke storage ring electron beam and the NIST undulator. Driven by a series of concerns and constraints over maximum utility, personnel safety and funding, we have also constructed a unique front end beamline for the undulator. The front end has been designed for maximum throughput of the 1st harmonic around 40A in its standard mode of operation. The front end has an alternative mode of operation which transmits the 3rd and 5th harmonics. This compact system also allows for the extraction of some of the bend magnet produced synchrotron and transition radiation from the storage ring. As with any well designed front end system, it also provides excellent protection to personnel and to the

  6. Laboratory-Based Cryogenic Soft X-ray Tomography with Correlative Cryo-Light and Electron Microscopy

    SciTech Connect

    Carlson, David B.; Gelb, Jeff; Palshin, Vadim; Evans, James E.

    2013-02-01

    Here we present a novel laboratory-based cryogenic soft X-ray microscope for whole cell tomography of frozen hydrated samples. We demonstrate the capabilities of this compact cryogenic microscope by visualizing internal sub-cellular structures of Saccharomyces cerevisiae cells. The microscope is shown to achieve better than 50 nm spatial resolution with a Siemens star test sample. For whole biological cells, the microscope can image specimens up to 5 micrometers thick. Structures as small as 90 nm can be detected in tomographic reconstructions at roughly 70 nm spatial resolution following a low cumulative radiation dose of only 7.2 MGy. Furthermore, the design of the specimen chamber utilizes a standard sample support that permits multimodal correlative imaging of the exact same unstained yeast cell via cryo-fluorescence light microscopy, cryo-soft x-ray microscopy and cryo-transmission electron microscopy. This completely laboratory-based cryogenic soft x-ray microscope will therefore enable greater access to three-dimensional ultrastructure determination of biological whole cells without chemical fixation or physical sectioning.

  7. Synchrotron radiation induced x-ray micro analysis: A realistic alternative for electron- and ion beam microscopy?

    SciTech Connect

    Janssens, K.; Adams, F.; Rivers, M.L.; Jones, K.W.

    1992-10-01

    Synchrotron Radiation induced X-ray micro Fluorescence analysis ({mu}-SRXRF) is compared with more conventional microanalytical techniques such as Secondary Ion Microscopy (SIMS) and Electron Probe X-ray Microanalysis (EPXMA) for two typical microanalytical applications. SRXRF and EPXMA are employed for the analysis of individual particles, showing the complementary character of both techniques. By means of element mapping of trace constituents in a heterogeneous feldspar, the strong and weak points of SRXRF in comparison to EPXMA and SIMS are illustrated. The most striking difference between SRXRF and the other two microanalytical methods is the ability of SRXRF to probe deep into the investigated Material, whereas SIMS and EPXMA only investigate the upper surface of the material. The possibilities of SRXRF at third generation synchrotron rings is also briefly discussed.

  8. Synchrotron radiation induced x-ray micro analysis: A realistic alternative for electron- and ion beam microscopy

    SciTech Connect

    Janssens, K.; Adams, F. . Dept. of Chemistry); Rivers, M.L.; Jones, K.W. )

    1992-01-01

    Synchrotron Radiation induced X-ray micro Fluorescence analysis ([mu]-SRXRF) is compared with more conventional microanalytical techniques such as Secondary Ion Microscopy (SIMS) and Electron Probe X-ray Microanalysis (EPXMA) for two typical microanalytical applications. SRXRF and EPXMA are employed for the analysis of individual particles, showing the complementary character of both techniques. By means of element mapping of trace constituents in a heterogeneous feldspar, the strong and weak points of SRXRF in comparison to EPXMA and SIMS are illustrated. The most striking difference between SRXRF and the other two microanalytical methods is the ability of SRXRF to probe deep into the investigated Material, whereas SIMS and EPXMA only investigate the upper surface of the material. The possibilities of SRXRF at third generation synchrotron rings is also briefly discussed.

  9. X-ray diffraction and electron microscopy data for amyloid formation of Aβ40 and Aβ42.

    PubMed

    Selivanova, Olga M; Grigorashvili, Elizaveta I; Suvorina, Mariya Yu; Dzhus, Ulyana F; Nikulin, Alexey D; Marchenkov, Victor V; Surin, Alexey K; Galzitskaya, Oxana V

    2016-09-01

    The data presented in this article are related to the research article entitled "One of the possible mechanisms of amyloid fibrils formation based on the sizes of primary and secondary folding nuclei of Aβ40 and Aβ42" (Dovidchenko et al., 2016) [1]. Aβ peptide is one of the most intensively studied amyloidogenic peptides. Despite the huge number of articles devoted to studying different fragments of Aβ peptide there are only several papers with correct kinetics data, also there are a few papers with X-ray data, especially for Aβ42. Our data present X-ray diffraction patterns both for Aβ40 and Aβ42 as well for Tris-HCl and wax. Moreover, our data provide kinetics of amyloid formation by recombinant Аβ40 and synthetic Аβ42 peptides by using electron microscopy. PMID:27294177

  10. Comparison of synchrotron x-ray microanalysis with electron and proton microscopy for individual particle analysis

    SciTech Connect

    Janssens, K.H.; van Langevelde, F.; Adams, F.C.; Vis, R.D.; Sutton, S.R.; Rivers, M.L.; Jones, K.W.; Bowen, D.K.

    1991-12-31

    This paper is concerned with the evaluation of the use of synchrotron/radiation induced x-ray fluorescences ({mu}-SRXRF) as implemented at two existing X-ray microprobes for the analysis of individual particles. As representative environmental particulates, National Institutes of Science and Technology (NIST) K227, K309, K441 and K961 glass microspheres were analyzed using two types of X-ray micro probes: the white light microprobe at beamline X26A of the monochromatic (15 keV) X-ray microprobe at station 7.6 of the SRS. For reference, the particles were also analyzed with microanalytical techniques more commonly employed for individual particles analysis such as EPMA and micro-PIXE.

  11. Comparison of synchrotron x-ray microanalysis with electron and proton microscopy for individual particle analysis

    SciTech Connect

    Janssens, K.H.; van Langevelde, F.; Adams, F.C. ); Vis, R.D. ); Sutton, S.R.; Rivers, M.L. ); Jones, K.W. ); Bowen, D.K. )

    1991-01-01

    This paper is concerned with the evaluation of the use of synchrotron/radiation induced x-ray fluorescences ({mu}-SRXRF) as implemented at two existing X-ray microprobes for the analysis of individual particles. As representative environmental particulates, National Institutes of Science and Technology (NIST) K227, K309, K441 and K961 glass microspheres were analyzed using two types of X-ray micro probes: the white light microprobe at beamline X26A of the monochromatic (15 keV) X-ray microprobe at station 7.6 of the SRS. For reference, the particles were also analyzed with microanalytical techniques more commonly employed for individual particles analysis such as EPMA and micro-PIXE.

  12. Multivariate statistics applications in scanning transmission electron microscopy X-ray spectrum imaging

    SciTech Connect

    Parish, Chad M

    2011-01-01

    A modern scanning transmission electron microscope (STEM) fitted with an energy dispersive X-ray spectroscopy (EDS) system can quickly and easily produce spectrum image (SI) datasets containing so much information (hundreds to thousands of megabytes) that they cannot be comprehensively interrogated by a human analyst. Therefore, advanced mathematical techniques are needed to glean materials science and engineering insight into the processing-structure-properties relationship of the examined material from the SI data. This review will discuss recent advances in the application of multivariate statistical analysis (MVSA) methods to STEM-EDS SI experiments. In particular, the fundamental mathematics of principal component analysis (PCA) and related methods are reviewed, and advanced methods such as multivariate curve resolution (MCR) are discussed. The applications of PCA and MCR-based techniques to solve difficult materials science problems, such as the analysis of a particle fully embedded in a matrix phase are discussed, as well as confounding effects such as rank deficiency that can confuse the results of MVSA computations. Possible future advances and areas in need of study are also mentioned.

  13. X-ray diffraction, XAFS and scanning electron microscopy study of otolith of a crevalle jack fish ( caranx hippos)

    NASA Astrophysics Data System (ADS)

    Pattanaik, Sidhartha

    2005-04-01

    The otolith of a crevalle jack fish (caranx hippos) has been investigated by means of X-ray diffraction, X-ray absorption fine structure spectroscopy and scanning electron microscopy techniques. The results suggest that the biomineralization of otolith occurs predominantly in the aragonite phase. A detailed X-ray Rietveld analysis showed that the first shell Ca-O distances in otolith lay in the range 2.371-2.652 Å, with each calcium atom coordinated to 9 oxygen atoms. While the average Ca-O distance remains same in both otolith and aragonite, certain Ca-O distances in otolith differ markedly from those in aragonite. Such difference reflects the remarkable degree of control that the protein matrix exercised over packing of calcium and carbonate ions to promote growth of rarer aragonite otolith. In view of the complex coordination chemistry of calcium in otoliths, the EXAFS analysis was limited to obtaining local atomic environment about calcium up to the first Ca-O shell. EXAFS data showed an asymmetric distribution of Ca-O bond distances with the centroid of distribution at 2.48 Å, which is closer to the average Ca-O distance in aragonite than in calcite. The asymmetry in the Ca-O peak is consistent with an apparent departure of Ca-O distances from a near regular distribution, as expected of an aragonite otolith.

  14. Scanning Transmission X-Ray, Laser Scanning, and Transmission Electron Microscopy Mapping of the Exopolymeric Matrix of Microbial Biofilms

    PubMed Central

    Lawrence, J. R.; Swerhone, G. D. W.; Leppard, G. G.; Araki, T.; Zhang, X.; West, M. M.; Hitchcock, A. P.

    2003-01-01

    Confocal laser scanning microscopy (CLSM), transmission electron microscopy (TEM), and soft X-ray scanning transmission X-ray microscopy (STXM) were used to map the distribution of macromolecular subcomponents (e.g., polysaccharides, proteins, lipids, and nucleic acids) of biofilm cells and matrix. The biofilms were developed from river water supplemented with methanol, and although they comprised a complex microbial community, the biofilms were dominated by heterotrophic bacteria. TEM provided the highest-resolution structural imaging, CLSM provided detailed compositional information when used in conjunction with molecular probes, and STXM provided compositional mapping of macromolecule distributions without the addition of probes. By examining exactly the same region of a sample with combinations of these techniques (STXM with CLSM and STXM with TEM), we demonstrate that this combination of multimicroscopy analysis can be used to create a detailed correlative map of biofilm structure and composition. We are using these correlative techniques to improve our understanding of the biochemical basis for biofilm organization and to assist studies intended to investigate and optimize biofilms for environmental remediation applications. PMID:12957944

  15. Soft x-ray laser microscopy

    SciTech Connect

    DiCicco, D.; Meixler, L.; Skinner, C.H.; Suckewer, S.; Hirschberg, J.; Kohen, E.

    1987-12-31

    Microscopes based on soft X-ray lasers possess unique advantages in bridging the gap between high resolution electron microscopy of dehydrated, stained cells and light microscopy at comparatively low resolution of unaltered live cells. The high brightness and short pulse duration of soft X-ray lasers make them ideal for flash imaging of live specimens. The Princeton soft X-ray laser is based on a magnetically confined laser produced carbon plasma. Radiation cooling after the laser pulse produces rapid recombination which produces a population inversion and high gain. A full account is given in a companion paper in this volume. The important characteristics of the laser beam produced by this device are 1 to 3 mJ of 18.2 nm radiation in a 10 to 30 nsec pulse with a divergence of 5 mrad. The 18.2 nm wavelength, while outside the water window, does provide a factor of 3 difference in absorption coefficients between oxygen and carbon.

  16. Soft x-ray laser microscopy

    SciTech Connect

    DiCicco, D. ); Meixler, L.; Skinner, C.H.; Suckewer, S. . Plasma Physics Lab.); Hirschberg, J.; Kohen, E. . Dept. of Physics)

    1987-01-01

    Microscopes based on soft X-ray lasers possess unique advantages in bridging the gap between high resolution electron microscopy of dehydrated, stained cells and light microscopy at comparatively low resolution of unaltered live cells. The high brightness and short pulse duration of soft X-ray lasers make them ideal for flash imaging of live specimens. The Princeton soft X-ray laser is based on a magnetically confined laser produced carbon plasma. Radiation cooling after the laser pulse produces rapid recombination which produces a population inversion and high gain. A full account is given in a companion paper in this volume. The important characteristics of the laser beam produced by this device are 1 to 3 mJ of 18.2 nm radiation in a 10 to 30 nsec pulse with a divergence of 5 mrad. The 18.2 nm wavelength, while outside the water window, does provide a factor of 3 difference in absorption coefficients between oxygen and carbon.

  17. X-ray microscopy using synchrotron radiation

    SciTech Connect

    Jones, K.W.; Gordon, B.M.; Hanson, A.L.; Pounds, J.G.; Rivers, M.L.; Schidlovsky, G.; Smith, J.V.; Spanne, P.; Sutton, S.R.

    1989-01-01

    The system for x-ray microscopy now being developed at the X-26 beam line of the Brookhaven National Synchrotron Light Source (NSLS) is described here. Examples of the use of x-ray microscopy for trace element geochemistry, biology and medicine, and materials investigations are given to emphasize the scientific applications of the technique. Future directions for the improvement and further development of the X-26 microscope and of the x-ray microscopy field in general are discussed. 11 refs., 7 figs.

  18. Roughness in sputtered multilayers analyzed by transmission electron microscopy and x-ray diffuse scattering.

    SciTech Connect

    Macrander, A. T.; Liu, C.; Csencsits, R.; Cook, R.; Kirk, M.; Headrick, R.

    1999-11-08

    Sputtered W/C muhilayers with a period of 25 {angstrom} have been studied both by cross-section TEM and by x-ray diffuse scattering using 10 keV synchrotrons radiation. Fitting to the x-ray data is aided by the TEM images in modeling the roughness and roughness propagation within the Born approximation. We report on a study of the correctness of the often applied small roughness approximation, and we find that is not well justified in the present case. In order to probe short lateral length scales at q{sub y} = 0.1 {angstrom}{sup -1}, diffuse scattering data were obtained in an unconventional scattering geometry.

  19. Development of wavelength-dispersive soft X-ray emission spectrometers for transmission electron microscopes--an introduction of valence electron spectroscopy for transmission electron microscopy.

    PubMed

    Terauchi, Masami; Koike, Masato; Fukushima, Kurio; Kimura, Atsushi

    2010-01-01

    Two types of wavelength-dispersive soft X-ray spectrometers, a high-dispersion type and a conventional one, for transmission electron microscopes were constructed. Those spectrometers were used to study the electronic states of valence electrons (bonding electrons). Both spectrometers extended the acceptable energy regions to higher than 2000 eV. The best energy resolution of 0.08 eV was obtained for an Al L-emission spectrum by using the high-dispersion type spectrometer. By using the spectrometer, C K-emission of carbon allotropes, Cu L-emission of Cu(1-x)Zn(x) alloys and Pt M-emission spectra were presented. The FWHM value of 12 eV was obtained for the Pt Malpha-emission peak. The performance of the conventional one was also presented for ZnS and a section specimen of a multilayer device. W-M and Si-K emissions were clearly resolved. Soft X-ray emission spectroscopy based on transmission electron microscopy (TEM) has an advantage for obtaining spectra from a single crystalline specimen with a defined crystal setting. As an example of anisotropic soft X-ray emission, C K-emission spectra of single crystalline graphite with different crystal settings were presented. From the spectra, density of states of pi- and sigma-bondings were separately derived. These results demonstrated a method to analyse the electronic states of valence electrons of materials in the nanometre scale based on TEM. PMID:20371492

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

    NASA Astrophysics Data System (ADS)

    Boatman, Elizabeth Marie

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

  1. Diffusion of Ag into organic semiconducting materials: a combined analytical study using transmission electron microscopy and X-ray reflectivity.

    PubMed

    Fladischer, Stefanie; Neuhold, Alfred; Kraker, Elke; Haber, Thomas; Lamprecht, Bernhard; Salzmann, Ingo; Resel, Roland; Grogger, Werner

    2012-10-24

    This study shows that the morphology of organic/metal interfaces strongly depends on process parameters and the involved materials. The interface between organic n-type blocking layer materials and the top Ag cathode within an organic photodiode was investigated. Ag was deposited on either amorphous tris-8-hydroxyquinolinato-aluminum (Alq(3)) or crystalline 4,7-diphenyl-1,10-phenanthroline (Bphen) using different deposition techniques such as electron beam deposition, ion beam sputtering, and vacuum thermal evaporation at various deposition rates. The interfaces were studied by transmission electron microscopy and X-ray reflectivity. It was found that Bphen does not show any Ag diffusion no matter which deposition technique was used, whereas the Ag diffusion into Alq(3) depends on the deposition technique and the deposition rate. The highest amount of Ag diffusion into Alq(3) occurred by using thermal vacuum deposition at low deposition rates. PMID:23027799

  2. From virus structure to chromatin: X-ray diffraction to three-dimensional electron microscopy.

    PubMed

    Klug, Aaron

    2010-01-01

    Early influences led me first to medical school with a view to microbiology, but I felt the lack of a deeper foundation and changed to chemistry, which in turn led me to physics and mathematics. I moved to the University of Cape Town to work on the X-ray crystallography of some small organic compounds. I developed a new method of using molecular structure factors to solve the crystal structure, which won me a research studentship to Trinity College Cambridge and the Cavendish Laboratory. There I worked on the austenite-pearlite transition in steel. This is governed by the dissipation of latent heat, and I ended up numerically solving partial differential equations. I used the idea of nucleation and growth during the phase change, which had its echo when I later tackled the assembly of Tobacco mosaic virus (TMV) from its constituent RNA and protein subunits. I wanted to move on to X-ray structure analysis of large biological molecules and obtained a Nuffield Fellowship to work in J.D. Bernal's department at Birkbeck College, London. There, I met Rosalind Franklin, who had taken up the study of TMV. I was able to interpret some of Franklin's beautiful X-ray diffraction patterns of the virus particle. From then on, my fate was sealed. After Franklin's untimely death in 1958, I moved in 1962 to the newly built MRC Laboratory of Molecular Biology in Cambridge, which, under Max Perutz, housed the original MRC unit from the Cavendish Laboratory. I was thus privileged to join the Laboratory at an early stage in its expansion and consequently able to take advantage of, and to help build up, its then unique environment of intellectual and technological sophistication. There I have remained ever since. PMID:20192760

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

    NASA Astrophysics Data System (ADS)

    Isaure, Marie-Pierre; Fayard, Barbara; Sarret, Géraldine; Pairis, Sébastien; Bourguignon, Jacques

    2006-12-01

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

  4. The architecture of amyloid-like peptide fibrils revealed by X-ray scattering, diffraction and electron microscopy

    SciTech Connect

    Langkilde, Annette E.; Morris, Kyle L.; Serpell, Louise C.; Svergun, Dmitri I.; Vestergaard, Bente

    2015-04-01

    The aggregation process and the fibril state of an amyloidogenic peptide suggest monomer addition to be the prevailing mechanism of elongation and a model of the peptide packing in the fibrils has been obtained. Structural analysis of protein fibrillation is inherently challenging. Given the crucial role of fibrils in amyloid diseases, method advancement is urgently needed. A hybrid modelling approach is presented enabling detailed analysis of a highly ordered and hierarchically organized fibril of the GNNQQNY peptide fragment of a yeast prion protein. Data from small-angle X-ray solution scattering, fibre diffraction and electron microscopy are combined with existing high-resolution X-ray crystallographic structures to investigate the fibrillation process and the hierarchical fibril structure of the peptide fragment. The elongation of these fibrils proceeds without the accumulation of any detectable amount of intermediate oligomeric species, as is otherwise reported for, for example, glucagon, insulin and α-synuclein. Ribbons constituted of linearly arranged protofilaments are formed. An additional hierarchical layer is generated via the pairing of ribbons during fibril maturation. Based on the complementary data, a quasi-atomic resolution model of the protofilament peptide arrangement is suggested. The peptide structure appears in a β-sheet arrangement reminiscent of the β-zipper structures evident from high-resolution crystal structures, with specific differences in the relative peptide orientation. The complexity of protein fibrillation and structure emphasizes the need to use multiple complementary methods.

  5. HERMES: a soft X-ray beamline dedicated to X-ray microscopy.

    PubMed

    Belkhou, Rachid; Stanescu, Stefan; Swaraj, Sufal; Besson, Adrien; Ledoux, Milena; Hajlaoui, Mahdi; Dalle, Didier

    2015-07-01

    The HERMES beamline (High Efficiency and Resolution beamline dedicated to X-ray Microscopy and Electron Spectroscopy), built at Synchrotron SOLEIL (Saint-Auban, France), is dedicated to soft X-ray microscopy. The beamline combines two complementary microscopy methods: XPEEM (X-ray Photo Emitted Electron Microscopy) and STXM (Scanning Transmission X-ray Microscopy) with an aim to reach spatial resolution below 20 nm and to fully exploit the local spectroscopic capabilities of the two microscopes. The availability of the two methods within the same beamline enables the users to select the appropriate approach to study their specific case in terms of sample environment, spectroscopy methods, probing depth etc. In this paper a general description of the beamline and its design are presented. The performance and specifications of the beamline will be reviewed in detail. Moreover, the article is aiming to demonstrate how the beamline performances have been specifically optimized to fulfill the specific requirements of a soft X-ray microscopy beamline in terms of flux, resolution, beam size etc. Special attention has been dedicated to overcome some limiting and hindering problems that are usually encountered on soft X-ray beamlines such as carbon contamination, thermal stability and spectral purity. PMID:26134801

  6. X-ray deconvolution microscopy

    PubMed Central

    Ehn, Sebastian; Epple, Franz Michael; Fehringer, Andreas; Pennicard, David; Graafsma, Heinz; Noël, Peter; Pfeiffer, Franz

    2016-01-01

    Recent advances in single-photon-counting detectors are enabling the development of novel approaches to reach micrometer-scale resolution in x-ray imaging. One example of such a technology are the MEDIPIX3RX-based detectors, such as the LAMBDA which can be operated with a small pixel size in combination with real-time on-chip charge-sharing correction. This characteristic results in a close to ideal, box-like point spread function which we made use of in this study. The proposed method is based on raster-scanning the sample with sub-pixel sized steps in front of the detector. Subsequently, a deconvolution algorithm is employed to compensate for blurring introduced by the overlap of pixels with a well defined point spread function during the raster-scanning. The presented approach utilizes standard laboratory x-ray equipment while we report resolutions close to 10 μm. The achieved resolution is shown to follow the relationship pn with the pixel-size p of the detector and the number of raster-scanning steps n. PMID:27446649

  7. Electronic structure of the carbon nanotube tips studied by x-ray-absorption spectroscopy and scanning photoelectron microscopy

    NASA Astrophysics Data System (ADS)

    Chiou, J. W.; Yueh, C. L.; Jan, J. C.; Tsai, H. M.; Pong, W. F.; Hong, I.-H.; Klauser, R.; Tsai, M.-H.; Chang, Y. K.; Chen, Y. Y.; Wu, C. T.; Chen, K. H.; Wei, S. L.; Wen, C. Y.; Chen, L. C.; Chuang, T. J.

    2002-11-01

    Angle-dependent x-ray absorption near edge structure (XANES) and scanning photoelectron microscopy (SPEM) measurements have been performed to differentiate local electronic structures of the tips and sidewalls of highly aligned carbon nanotubes. The intensities of both π*- and σ*-band C K-edge XANES features are found to be significantly enhanced at the tip. SPEM results also show that the tips have a larger density of states and a higher C 1s binding energy than those of sidewalls. The increase of the tip XANES and SPEM intensities are quite uniform over an energy range wider than 10 eV in contrast to earlier finding that the enhancement is only near the Fermi level.

  8. Scanning Electron Microscopy Findings With Energy-Dispersive X-ray Investigations of Cosmetically Tinted Contact Lenses

    PubMed Central

    Hotta, Fumika; Imai, Shoji; Miyamoto, Tatsuro; Mitamura-Aizawa, Sayaka; Mitamura, Yoshinori

    2015-01-01

    Objective: To investigate the surfaces and principal elements of the colorants of cosmetically tinted contact lenses (Cos-CLs). Methods: We analyzed the surfaces and principal elements of the colorants of five commercially available Cos-CLs using scanning electron microscopy with energy-dispersive x-ray analysis. Results: In two Cos-CLs, the anterior and posterior surfaces were smooth, and colorants were found inside the lens. One lens showed colorants located to a depth of 8 to 14 μm from the anterior side of the lens. In the other lens, colorants were found in the most superficial layer on the posterior surface, although a coated layer was observed. The colorants in the other three lenses were deposited on either lens surface. Although a print pattern was uniform in embedded type lenses, uneven patterns were apparent in dot-matrix design lenses. Colorants used in all lenses contained chlorine, iron, and titanium. In the magnified scanning electron microscopy images of a certain lens, chlorine is exuded and spread. Conclusions: Cosmetically tinted contact lenses have a wide variety of lens surfaces and colorants. Colorants may be deposited on the lens surface and consist of an element that has tissue toxicity. PMID:25799458

  9. Soft x-ray holographic microscopy

    NASA Astrophysics Data System (ADS)

    Stickler, Daniel; Frömter, Robert; Stillrich, Holger; Menk, Christian; Tieg, Carsten; Streit-Nierobisch, Simone; Sprung, Michael; Gutt, Christian; Stadler, Lorenz-M.; Leupold, Olaf; Grübel, Gerhard; Oepen, Hans Peter

    2010-01-01

    We present a new x-ray microscopy technique based on Fourier transform holography (FTH), where the sample is separate from the optics part of the setup. The sample can be shifted with respect to the holography optics, thus large-scale or randomly distributed objects become accessible. As this extends FTH into a true microscopy technique, we call it x-ray holographic microscopy (XHM). FTH allows nanoscale imaging without the need for nanometer-size beams. Simple Fourier transform yields an unambiguous image reconstruction. We demonstrate XHM by studying the magnetic domain evolution of a Co/Pt multilayer film as function of locally varied iron overlayer thickness.

  10. Freeze stabilization and cryopreparation technique for visualizing the water distribution in woody tissues by X-ray imaging and cryo-scanning electron microscopy.

    PubMed

    Utsumi, Yasuhiro; Sano, Yuzou

    2014-01-01

    The protocol of freeze stabilization and cryopreparation techniques to examine the distribution of water in living tree stems by X-ray imaging and cryo-scanning electron microscopy have been developed and described. The brief procedures are as follows. Firstly, a portion of transpiring stem is frozen in the standing state with liquid nitrogen to stabilize the water that is present in the conducting tissue. After filling with liquid nitrogen, discs are then collected from the frozen portion of the stem and stored in liquid nitrogen. In a low-temperature room, the samples for X-ray imaging are sectioned with a fine handsaw, and trimmed sample blokes for cryo-scanning electron microscopy are cleanly planed using a sliding microtome. Finally, the frozen sections are irradiated in a soft X-ray apparatus, and the small blocks are examined in cryo-scanning electron microscope after freeze-etching and metal coating. PMID:24357385

  11. X-ray Microscopy as an Approach to Increasing Accuracy and Efficiency of Serial Block-face Imaging for Correlated Light and Electron Microscopy of Biological Specimens

    PubMed Central

    Bushong, Eric A.; Johnson, Donald D.; Kim, Keun-Young; Terada, Masako; Hatori, Megumi; Peltier, Steven T.; Panda, Satchidananda; Merkle, Arno; Ellisman, Mark H.

    2015-01-01

    The recently developed three-dimensional electron microscopic (EM) method of serial block-face scanning electron microscopy (SBEM) has rapidly established itself as a powerful imaging approach. Volume EM imaging with this scanning electron microscopy (SEM) method requires intense staining of biological specimens with heavy metals to allow sufficient back-scatter electron signal and also to render specimens sufficiently conductive to control charging artifacts. These more extreme heavy metal staining protocols render specimens light opaque and make it much more difficult to track and identify regions of interest (ROIs) for the SBEM imaging process than for a typical thin section transmission electron microscopy correlative light and electron microscopy study. We present a strategy employing X-ray microscopy (XRM) both for tracking ROIs and for increasing the efficiency of the workflow used for typical projects undertaken with SBEM. XRM was found to reveal an impressive level of detail in tissue heavily stained for SBEM imaging, allowing for the identification of tissue landmarks that can be subsequently used to guide data collection in the SEM. Furthermore, specific labeling of individual cells using diaminobenzidine is detectable in XRM volumes. We demonstrate that tungsten carbide particles or upconverting nanophosphor particles can be used as fiducial markers to further increase the precision and efficiency of SBEM imaging. PMID:25392009

  12. X-ray microscopy as an approach to increasing accuracy and efficiency of serial block-face imaging for correlated light and electron microscopy of biological specimens.

    PubMed

    Bushong, Eric A; Johnson, Donald D; Kim, Keun-Young; Terada, Masako; Hatori, Megumi; Peltier, Steven T; Panda, Satchidananda; Merkle, Arno; Ellisman, Mark H

    2015-02-01

    The recently developed three-dimensional electron microscopic (EM) method of serial block-face scanning electron microscopy (SBEM) has rapidly established itself as a powerful imaging approach. Volume EM imaging with this scanning electron microscopy (SEM) method requires intense staining of biological specimens with heavy metals to allow sufficient back-scatter electron signal and also to render specimens sufficiently conductive to control charging artifacts. These more extreme heavy metal staining protocols render specimens light opaque and make it much more difficult to track and identify regions of interest (ROIs) for the SBEM imaging process than for a typical thin section transmission electron microscopy correlative light and electron microscopy study. We present a strategy employing X-ray microscopy (XRM) both for tracking ROIs and for increasing the efficiency of the workflow used for typical projects undertaken with SBEM. XRM was found to reveal an impressive level of detail in tissue heavily stained for SBEM imaging, allowing for the identification of tissue landmarks that can be subsequently used to guide data collection in the SEM. Furthermore, specific labeling of individual cells using diaminobenzidine is detectable in XRM volumes. We demonstrate that tungsten carbide particles or upconverting nanophosphor particles can be used as fiducial markers to further increase the precision and efficiency of SBEM imaging. PMID:25392009

  13. X-ray microscopy of human malaria

    SciTech Connect

    Magowan, C.; Brown, J.T.; Mohandas, N.; Meyer-Ilse, W.

    1997-04-01

    Associations between intracellular organisms and host cells are complex and particularly difficult to examine. X-ray microscopy provides transmission images of subcellular structures in intact cells at resolutions superior to available methodologies. The spatial resolution is 50-60nm with a 1 micron depth of focus, superior to anything achievable with light microscopy. Image contrast is generated by differences in photoelectric absorption by the atoms in different areas (i.e. subcellular structures) throughout the full thickness of the sample. Absorption due to carbon dominates among all the elements in the sample at 2.4 nm x-ray wavelength. Thus images show features or structures, in a way not usually seen by other types of microscopy. The authors used soft x-ray microscopy to investigate structural development of Plasmodium falciparum malaria parasites in normal and genetically abnormal erythrocytes, and in infected erythrocytes treated with compounds that have anti-malarial effects. X-ray microscopy showed newly elaborated structures in the cytosol of unstained, intact erythrocytes, redistribution of mass (carbon) in infected erythrocytes, and aberrant parasite morphology. Better understanding of the process of intracellular parasite maturation and the interactions between the parasite and its host erythrocyte can help define new approaches to the control of this deadly disease.

  14. Application of scanning electron microscopy to x-ray analysis of frozen- hydrated sections. I. Specimen handling techniques

    PubMed Central

    1981-01-01

    X-ray microanalysis of frozen-hydrated tissue sections permits direct quantitative analysis of diffusible elements in defined cellular compartments. Because the sections are hydrated, elemental concentrations can be defined as wet-weight mass fractions. Use of these techniques should also permit determination of water fraction in cellular compartments. Reliable preparative techniques provide flat, smooth, 0.5 micrometers-thick sections with little elemental and morphological disruption. The specimen support and transfer system described permits hydrated sections to be transferred to the scanning electron microscope cold stage for examination and analysis without contamination or water loss and without introduction of extraneous x- ray radiation. PMID:7204491

  15. In Depth Analyses of LEDs by a Combination of X-ray Computed Tomography (CT) and Light Microscopy (LM) Correlated with Scanning Electron Microscopy (SEM).

    PubMed

    Meyer, Jörg; Thomas, Christian; Tappe, Frank; Ogbazghi, Tekie

    2016-01-01

    In failure analysis, device characterization and reverse engineering of light emitting diodes (LEDs), and similar electronic components of micro-characterization, plays an important role. Commonly, different techniques like X-ray computed tomography (CT), light microscopy (LM) and scanning electron microscopy (SEM) are used separately. Similarly, the results have to be treated for each technique independently. Here a comprehensive study is shown which demonstrates the potentials leveraged by linking CT, LM and SEM. In depth characterization is performed on a white emitting LED, which can be operated throughout all characterization steps. Major advantages are: planned preparation of defined cross sections, correlation of optical properties to structural and compositional information, as well as reliable identification of different functional regions. This results from the breadth of information available from identical regions of interest (ROIs): polarization contrast, bright and dark-field LM images, as well as optical images of the LED cross section in operation. This is supplemented by SEM imaging techniques and micro-analysis using energy dispersive X-ray spectroscopy. PMID:27341190

  16. NASA Li/CF(x) cell problem analysis: Scanning electron microscopy with energy dispersive x ray spectrometry

    NASA Technical Reports Server (NTRS)

    Baker, John

    1991-01-01

    An analysis was made of Lithium/carbon fluoride cell parts for possible chloride contamination induced by exposure to thionyl chloride (SOCl2); various samples were submitted for analysis. Only a portion of the analysis which has been conducted is covered, herein, namely analysis by scanning electron microscopy with energy dispersive x ray spectrometry (SEM/EDS). A strip of nickel was exposed to SOCl2 vapors to observe variations in surface concentrations of sulfur and chlorine with time. By detecting chlorine one can not infer contamination by SOCl2 only that contamination is present. Six samples of stainless steel foil were analyzed for chlorine using EDS. Chlorine was not detected on background samples but was detected on the samples which had been handled including those which had been cleaned. Cell covers suspected of being contaminated while in storage and covers which were not exposed to the same storage conditions were analyzed for chlorine. Although no chlorine was found on the covers from cells, it was found on all stored covers. Results are presented with techniques shown for analysis and identification. Relevant photomicrographs are presented.

  17. Sub-nanosecond resolution x-ray magnetic circular dichroism photoemission electron microscopy of magnetization processes in a permalloy ring

    NASA Astrophysics Data System (ADS)

    Neeb, D.; Krasyuk, A.; Oelsner, A.; Nepijko, S. A.; Elmers, H. J.; Kuksov, A.; Schneider, C. M.; Schönhense, G.

    2005-04-01

    Fast magnetization processes in a microstructured permalloy ring with 80 µm o.d. and 30 nm thickness have been observed by photoemission electron microscopy exploiting x-ray magnetic circular dichroism as the magnetic contrast mechanism. As a high speed probe we employed synchrotron radiation pulses at the ESRF (Grenoble) operated in 16-bunch mode, yielding photon pulses of 105 ps FWHM with a period of 176 ns. Fast magnetic field pulses have been generated by means of current pulses through coplanar waveguides with the magnetic structure being lithographically prepared on their surface. A stroboscopic pump-probe set-up with a variable time delay between the field pulse and photon pulse allowed us to take snapshots of the dynamic response of the magnetic domain structure. We observed coherent magnetization rotation during the leading edge part of the field pulse, the formation of a characteristic domain pattern ('onion state') in the plateau region of the pulse and the fast formation of a striped domain pattern (incoherent magnetization rotation) during the trailing edge part of the field pulse. A numerical simulation confirmed essential features of the stroboscopic image series.

  18. XRD (x-ray diffraction) and HREM (high resolution electron microscopy) studies of nanocrystalline Cu and Pd

    SciTech Connect

    Nieman, G.W.; Weertman, J.R. . Dept. of Materials Science and Engineering); Siegel, R.W. )

    1990-12-01

    Consolidated powders of nanocrystalline Cu and Pd have been studied by x-ray diffraction (XRD) and high resolution electron microscopy (HREM) as part of an investigation of the mechanical behavior of nanocrystalline pure metals. XRD line broadening measurements were made to estimate grain size, qualitative grain size distribution and average long range strains in a number of samples. Mean grain sizes range from 4--60 nm and have qualitatively narrow grain size distributions. Long range lattice strains are of the order of 0.2--3% in consolidated samples. These strains apparently persist and even increase in Cu samples after annealing at 0.35 Tm (498K) for 2h, accompanied by an apparent increase in grain size of {ge}2x. Grain size, grain size distribution width and internal strains vary somewhat among samples produced under apparently identical processing conditions. HREM studies show that twins, stacking faults and low-index facets are abundant in as-consolidated nanocrystalline Cu samples. Methodology, results, and analysis of XRD and HREM experiments are presented. 17 refs., 2 figs., 2 tabs.

  19. Synchrotron X-ray diffraction and scanning electron microscopy to understand enamel affected by metabolic disorder mucopolysaccharidosis.

    PubMed

    Khan, Malik Arshman; Addison, Owen; James, Alison; Hendriksz, Christian J; Al-Jawad, Maisoon

    2016-04-01

    Mucopolysaccharidosis (MPS) is an inherited metabolic disorder that can affect the tooth structure leading to defects. Synchrotron X-ray diffraction being a state of the art technique has been used to determine the enamel crystallite orientation in deciduous enamel affected by Mucopolysaccharidosis Type I and Mucopolysaccharidosis Type IVA and comparing these with that of healthy deciduous enamel. Using this technique it was observed that there is a loss of texture in deciduous enamel affected by Mucopolysaccharidosis Type I and Mucopolysaccharidosis Type IVA when compared to the healthy deciduous enamel. Generally it was observed that the incisal surface of the deciduous teeth possessed a higher texture or preferred orientation of enamel crystallites and on progression towards the cervical region there was a decrease in the texture or preferred orientation of enamel crystallites. Scanning electron microscopy showed that the presence of a poorly calcified layer between the enamel and dentine at the enamel-dentine junction (EDJ) in MPS affected samples was likely to be responsible for rendering the tooth structure weak and prone to fracture as is often the case in MPS affected deciduous enamel. PMID:26896739

  20. Characterization of leaf-level particulate matter for an industrial city using electron microscopy and X-ray microanalysis.

    PubMed

    Sgrigna, G; Baldacchini, C; Esposito, R; Calandrelli, R; Tiwary, A; Calfapietra, C

    2016-04-01

    This study reports application of monitoring and characterization protocol for particulate matter (PM) deposited on tree leaves, using Quercus ilex as a case study species. The study area is located in the industrial city of Terni in central Italy, with high PM concentrations. Four trees were selected as representative of distinct pollution environments based on their proximity to a steel factory and a street. Wash off from leaves onto cellulose filters were characterized using scanning electron microscopy and energy dispersive X-ray spectroscopy, inferring the associations between particle sizes, chemical composition, and sampling location. Modeling of particle size distributions showed a tri-modal fingerprint, with the three modes centered at 0.6 (factory related), 1.2 (urban background), and 2.6μm (traffic related). Chemical detection identified 23 elements abundant in the PM samples. Principal component analysis recognized iron and copper as source-specific PM markers, attributed mainly to industrial and heavy traffic pollution respectively. Upscaling these results on leaf area basis provided a useful indicator for strategic evaluation of harmful PM pollutants using tree leaves. PMID:26802337

  1. Investigation of metal dusting mechanism in Fe-base alloys using Raman spectroscopy, x-ray diffraction, and electron microscopy.

    SciTech Connect

    Zeng, Z.; Natesan, K.; Maroni, V. A.

    2002-08-01

    The metal-dusting phenomenon, which is a metal loss process that occurs in hot reactive gases, was investigated in iron and certain iron-base alloys by Raman scattering, X-ray diffraction (XRD), and scanning-electron microscopy (SEM). Coke from metal dusting exhibits six Raman bands at 1330(D band), 1580(G band), 1617, 2685, 3920, and 3235 cm-1. The bandwidths and the relative intensities of the 1330 and 1580 cm-1 bands are related to the crystallinity and defect structure of the coke. Both Raman and XRD analyses suggest that the metal-dusting process influences the catalytic crystallization of carbon. A new mechanism of metal dusting is, therefore, proposed, based on the premise that coke cannot crystallize well by deposition from carburizing gases at low temperature without catalytic activation because of its strong C-C bonds and high melting temperature. Cementite or iron participates in the coke-crystallizing process in a manner that tends to improve the crystallinity of the coke. At the same time, fine iron or cementite particles are liberated from the pure metal or alloys.

  2. Effects of Pamidronate on Dental Enamel Formation Assessed by Light Microscopy, Energy-Dispersive X-Ray Analysis, Scanning Electron Microscopy, and Microhardness Testing.

    PubMed

    Soares, Ana P; do Espírito Santo, Renan F; Line, Sérgio R P; Pinto, Maria das G F; Santos, Pablo de M; Toralles, Maria Betania P; do Espírito Santo, Alexandre R

    2016-06-01

    The aim of the present work was to investigate birefringence and morphology of the secretory-stage enamel organic extracellular matrix (EOECM), and structural and mechanical properties of mature enamel of upper incisors from adult rats that had been treated with pamidronate disodium (0.5 mg/kg/week for 56 days), using transmitted polarizing and bright-field light microscopies (TPLM and BFLM), energy-dispersive X-ray (EDX) analysis, scanning electron microscopy (SEM) and microhardness testing. BFLM showed no morphological changes of the EOECM in pamidronate and control groups, but TPLM revealed a statistically significant reduction in optical retardation values of birefringence brightness of pamidronate-treated rats when compared with control animals (p0.05). The present study indicates that pamidronate can affect birefringence of the secretory-stage EOECM, which does not seem to be associated with significant changes in morphological and/or mechanical properties of mature enamel. PMID:27212049

  3. Scanning electron microscopy, X-ray diffraction and thermal analysis study of the TiH{sub 2} foaming agent

    SciTech Connect

    Mandrino, Djordje; Paulin, Irena; Skapin, Sreco D.

    2012-10-15

    The decomposition of commercially available TiH{sub 2} was investigated while performing different thermal treatments. TiH{sub 2} powder, which is widely used as a foaming agent, was heat treated at 450 Degree-Sign C for various times, from 15 min to 120 min. Scanning electron microscopy (SEM) images of the surfaces at different magnifications were obtained and interpreted. A Bragg-Brentano X-ray diffractometer was used to measure the X-ray diffraction (XRD) spectra on all five samples. A close examination of the diffraction spectra showed that for an as-received sample and samples undergoing the longest thermal treatment (1 and 2 h) these spectra can be explained as deriving from cubic TiH{sub 1.924}, while for the other two samples they can be explained as deriving from tetragonal TiH{sub 1.924}. A constant-unit-cell-volume phase transition between the cubic and tetragonal phases in TiH{sub 2-y}-type compounds had been described in the literature. The unit-cell parameters obtained from measured spectra confirm that within the measurement uncertainty the unit-cell volume is indeed constant in all five samples. Thermo-gravimetry (TG) and differential thermal analysis (DTA) measurements were performed on all the samples, showing that the intensity of the dehydrogenation depends on the previous treatment of the TiH{sub 2}. After the thermal analysis XRD of the samples was performed again and the material was found to exhibit a Ti-like unit cell, but slightly enlarged due to the unreleased hydrogen. - Highlights: Black-Right-Pointing-Pointer TiH{sub 2} samples were cubic or tetragonal TiH{sub 1.924} Black-Right-Pointing-Pointer Onset of the hydrogen release temperature increases with the pre-treatment time. Black-Right-Pointing-Pointer Thermal dehydrogenation for the as-prepared TiH{sub 2} is a three-step process. Black-Right-Pointing-Pointer After thermal analysis 2 residual hydrogen TiH{sub x} phases, close to {alpha}Ti, appeared.

  4. Laboratory cryo soft X-ray microscopy.

    PubMed

    Hertz, H M; von Hofsten, O; Bertilson, M; Vogt, U; Holmberg, A; Reinspach, J; Martz, D; Selin, M; Christakou, A E; Jerlström-Hultqvist, J; Svärd, S

    2012-02-01

    Lens-based water-window X-ray microscopy allows two- and three-dimensional (2D and 3D) imaging of intact unstained cells in their near-native state with unprecedented contrast and resolution. Cryofixation is essential to avoid radiation damage to the sample. Present cryo X-ray microscopes rely on synchrotron radiation sources, thereby limiting the accessibility for a wider community of biologists. In the present paper we demonstrate water-window cryo X-ray microscopy with a laboratory-source-based arrangement. The microscope relies on a λ=2.48-nm liquid-jet high-brightness laser-plasma source, normal-incidence multilayer condenser optics, 30-nm zone-plate optics, and a cryo sample chamber. We demonstrate 2D imaging of test patterns, and intact unstained yeast, protozoan parasites and mammalian cells. Overview 3D information is obtained by stereo imaging while complete 3D microscopy is provided by full tomographic reconstruction. The laboratory microscope image quality approaches that of the synchrotron microscopes, but with longer exposure times. The experimental image quality is analyzed from a numerical wave-propagation model of the imaging system and a path to reach synchrotron-like exposure times in laboratory microscopy is outlined. PMID:22119891

  5. Recent case histories of food product-metal container interactions using scanning electron microscopy-x-ray microanalysis.

    PubMed

    Charbonneau, J E

    1997-10-01

    Scanning electron microscopy (SEM) and x-ray microanalysis (EDS) were used to investigate stress corrosion cracking (SCC) in plain tinplate food cans, product discoloration, filiform corrosion, pitting/perforation corrosion, and loss of coating adhesion in enameled food cans. Intergranular SCC of uncoated tinplate occurred in canned pineapple juice. This is a rare occurrence in acid food products. The fracture developed in the can headspace only at the product line/metal interface by an interaction of the detinned metal surface with stress-inducing compounds in the product. Black discoloration of rice granules in the can headspace of a chicken and rice product was caused by the formation of metal sulfides. The source of the metal contamination was traced to metallic dirt in the coating on the tin-free-steel end. Blackening of light tan-colored olives and brine occurred after 1 year of storage in enameled tinplate containers as a result of pitting corrosion at the side seam weld. The cause of the pitting was a defective side seam stripe which failed to protect the weld. A perforation problem occurred at the score line of aluminum-tinplate bimetallic cans. The failure was caused by the high chloride content of the fruit product. Filiform corrosion resulted in perforations that occurred on the outside surfaces of two-piece tin-free steel cans packed with tuna. The cause of the corrosion was related to scratch defects in the exterior coating and the presence of chloride and sulfate cannery residues in the corroded areas. An enamel adhesion failure developed inside two-piece tin-free steel cans that contained mushrooms. Wrinkles in the coating which were introduced during can manufacture were cracked. The fractures were pathways for product-steel interaction which resulted in container failure. PMID:9353869

  6. Atomic level study of water-gas shift catalysts via transmission electron microscopy and x-ray spectroscopy

    NASA Astrophysics Data System (ADS)

    Akatay, Mehmed Cem

    Water-gas shift (WGS), CO + H2O ⇆ CO2 + H2 (DeltaH° = -41 kJ mol -1), is an industrially important reaction for the production of high purity hydrogen. Commercial Cu/ZnO/Al2O3 catalysts are employed to accelerate this reaction, yet these catalysts suffer from certain drawbacks, including costly regeneration processes and sulfur poisoning. Extensive research is focused on developing new catalysts to replace the current technology. Supported noble metals stand out as promising candidates, yet comprise intricate nanostructures complicating the understanding of their working mechanism. In this study, the structure of the supported Pt catalysts is explored by transmission electron microscopy and X-ray spectroscopy. The effect of the supporting phase and the use of secondary metals on the reaction kinetics is investigated. Structural heterogeneities are quantified and correlated with the kinetic descriptors of the catalysts to develop a fundamental understanding of the catalytic mechanism. The effect of the reaction environment on catalyst structure is examined by in-situ techniques. This study benefitted greatly from the use of model catalysts that provide a convenient medium for the atomic level characterization of nanostructures. Based on these studies, Pt supported on iron oxide nano islands deposited on inert spherical alumina exhibited 48 times higher WGS turnover rate (normalized by the total Pt surface area) than Pt supported on bulk iron oxide. The rate of aqueous phase glycerol reforming reaction of Pt supported on multiwall carbon nanotubes (MWCNT) is promoted by co-impregnating with cobalt. The synthesis resulted in a variety of nanostructures among which Pt-Co bimetallic nanoparticles are found to be responsible for the observed promotion. The unprecedented WGS rate of Pt supported on Mo2C is explored by forming Mo 2C patches on top of MWCNTs and the rate promotion is found to be caused by the Pt-Mo bimetallic entities.

  7. Gunshot residue testing in suicides: Part I: Analysis by scanning electron microscopy with energy-dispersive X-ray.

    PubMed

    Molina, D Kimberley; Martinez, Michael; Garcia, James; DiMaio, Vincent J M

    2007-09-01

    Several different methods can be employed to test for gunshot residue (GSR) on a deceased person's hands, including scanning electron microscopy with energy-dispersive x-ray spectroscopy (SEM-EDX) and inductively coupled plasma-atomic emission spectrometry (ICP-AES). Each of these techniques has been extensively studied, especially on living individuals. The current studies (Part I and Part II) were designed to compare the use and utility of the different GSR testing techniques in a medical examiner setting. In Part I, the hands of deceased persons who died from undisputed suicidal handgun wounds were tested for GSR by SEM-EDX over a 4-year period. A total of 116 cases were studied and analyzed for caliber of weapon, proximity of wound, and results of GSR testing, including spatial deposition upon the hands. It was found that in only 50% of cases with a known self-inflicted gunshot wound was SEM-EDX positive for at least 1 specific particle for GSR. In 18% of the cases there was a discernible pattern (spatial distribution) of the particles on the hand such that the manner in which the weapon was held could be determined. Since only 50% of cases where the person is known to have fired a weapon immediately prior to death were positive for GSR by SEM-EDX, this test should not be relied upon to determine whether a deceased individual has discharged a firearm. Furthermore, in only 18% of cases was a discernible pattern present indicating how the firearm was held. The low sensitivity, along with the low percentage of cases with a discernible pattern, limits the usefulness of GSR test results by SEM-EDX in differentiating self-inflicted from non-self-inflicted wounds. PMID:17721163

  8. Thermal analysis, X-ray powder diffraction and electron microscopy data related with the production of 1:1 Caffeine:Glutaric Acid cocrystals.

    PubMed

    Duarte, Íris; Andrade, Rita; Pinto, João F; Temtem, Márcio

    2016-09-01

    The data presented in this article are related to the production of 1:1 Caffeine:Glutaric Acid cocrystals as part of the research article entitled "Green production of cocrystals using a new solvent-free approach by spray congealing" (Duarte et al., 2016) [1]. More specifically, here we present the thermal analysis and the X-ray powder diffraction data for pure Glutaric Acid, used as a raw material in [1]. We also include the X-ray powder diffraction and electron microscopy data obtained for the 1:1 Caffeine:Glutaric Acid cocrystal (form II) produced using the cooling crystallization method reported in "Operating Regions in Cooling Cocrystallization of Caffeine and Glutaric Acid in Acetonitrile" (Yu et al., 2010) [2]. Lastly, we show the X-ray powder diffraction data obtained for assessing the purity of the 1:1 Caffeine:Glutaric cocrystals produced in [1]. PMID:27331096

  9. Scanning electron microscopy/energy dispersive spectrometry fixedbeam or overscan x-ray microanalysis of particles can miss the real structure: x-ray spectrum image mapping reveals the true nature

    NASA Astrophysics Data System (ADS)

    Newbury, Dale E.; Ritchie, Nicholas W. M.

    2013-05-01

    The typical strategy for analysis of a microscopic particle by scanning electron microscopy/energy dispersive spectrometry x-ray microanalysis (SEM/EDS) is to use a fixed beam placed at the particle center or to continuously overscan to gather an "averaged" x-ray spectrum. While useful, such strategies inevitably concede any possibility of recognizing microstructure within the particle, and such fine scale structure is often critical for understanding the origins, behavior, and fate of particles. Elemental imaging by x-ray mapping has been a mainstay of SEM/EDS analytical practice for many years, but the time penalty associated with mapping with older EDS technology has discouraged its general use and reserved it more for detailed studies that justified the time investment. The emergence of the high throughput, high peak stability silicon drift detector (SDD-EDS) has enabled a more effective particle mapping strategy: "flash" x-ray spectrum image maps can now be recorded in seconds that capture the spatial distribution of major (concentration, C > 0.1 mass fraction) and minor (0.01 <= C <= 0.1) constituents. New SEM/SDD-EDS instrument configurations feature multiple SDDs that view the specimen from widely spaced azimuthal angles. Multiple, simultaneous measurements from different angles enable x-ray spectrometry and mapping that can minimize the strong geometric effects of particles. The NIST DTSA-II software engine is a powerful aid for quantitatively analyzing EDS spectra measured individually as well as for mapping information (available free for Java platforms at: http://www.cstl.nist.gov/div837/837.02/epq/dtsa2/index.html).

  10. Visualization of the effects of electron microscopy fixatives on the structure of hydrated epidermal hairs of tomato (lycopersicum peruvianum) as revealed by soft x-ray contact microscopy

    NASA Astrophysics Data System (ADS)

    Stead, Anthony D.; Cotton, Robin A.; Page, Anton M.; Dooley, Mike D.; Ford, Thomas W.

    1993-01-01

    In order to examine the ultrastructure of biological specimens by electron microscopy it is necessary to stabilize the highly labile cellular contents before embedding and sectioning the specimens. This is commonly achieved by treating the tissues with various chemical fixatives. The assessment of the efficacy of these fixative is usually based upon the appearance of the specimen under the microscope although this is somewhat intuitive as the ultrastructure of the living cell cannot be studied. Previous studies, in which the structure of epidermal hairs has been followed under the light microscope as the commonly used fixatives are perfused into the tissue, have shown that the cellular contents are drastically rearranged by these fixatives. This paper describes the effects of some of the commonly used fixatives on cell ultrastructure using firstly electron microscopy and secondly soft x-ray contact microscopy. The latter technique allows not only direct comparisons of the effects of the fixatives but also allows living, hydrated specimens to be imaged so that the true ultrastructural effects of the fixatives can be seen and compared to the ultrastructure of the living material.

  11. Atmospheric electron x-ray spectrometer

    NASA Technical Reports Server (NTRS)

    Feldman, Jason E. (Inventor); George, Thomas (Inventor); Wilcox, Jaroslava Z. (Inventor)

    2002-01-01

    The present invention comprises an apparatus for performing in-situ elemental analyses of surfaces. The invention comprises an atmospheric electron x-ray spectrometer with an electron column which generates, accelerates, and focuses electrons in a column which is isolated from ambient pressure by a:thin, electron transparent membrane. After passing through the membrane, the electrons impinge on the sample in atmosphere to generate characteristic x-rays. An x-ray detector, shaping amplifier, and multi-channel analyzer are used for x-ray detection and signal analysis. By comparing the resultant data to known x-ray spectral signatures, the elemental composition of the surface can be determined.

  12. Electron beam parallel X-ray generator

    NASA Technical Reports Server (NTRS)

    Payne, P.

    1967-01-01

    Broad X ray source produces a highly collimated beam of low energy X rays - a beam with 2 to 5 arc minutes of divergence at energies between 1 and 6 keV in less than 5 feet. The X ray beam is generated by electron bombardment of a target from a large area electron gun.

  13. Towards high-resolution ptychographic x-ray diffraction microscopy

    SciTech Connect

    Takahashi, Yukio; Suzuki, Akihiro; Yamauchi, Kazuto; Zettsu, Nobuyuki; Kohmura, Yoshiki; Ishikawa, Tetsuya; Senba, Yasunori; Ohashi, Haruhiko

    2011-06-01

    Ptychographic x-ray diffraction microscopy is a lensless imaging technique with a large field of view and high spatial resolution, which is also useful for characterizing the wavefront of an x-ray probe. The performance of this technique is degraded by positioning errors due to the drift between the sample and illumination optics. We propose an experimental approach for correcting the positioning errors and demonstrate success by two-dimensionally reconstructing both the wavefront of the focused x-ray beam and the complex transmissivity of the weakly scattering objects at the pixel resolution of better than 10 nm in the field of view larger than 5 {mu}m. This method is applicable to not only the observation of organelles inside cells or nano-mesoscale structures buried within bulk materials but also the characterization of probe for single-shot imaging with x-ray free electron lasers.

  14. Recent trends of projection X-ray microscopy in Japan

    NASA Astrophysics Data System (ADS)

    Yada, K.

    2009-08-01

    Recent activities of projection X-ray microscopy in Japan are reviewed. 1) By employing high brightness Schottky electron gun, resolution of 0.1 µm is realized by Tohken CO. group and some application examples are shown. 2) Deblurring of Fresnel diffracted image formed by synchrotron orbital radiation (SOR) X-rays is successfully tried by Chiba University group. Remarkable Fresnel fringes appearing at HeLa cell are mostly reconstructed by an iteration method. 3) Element analysis is carried out by Meiji University group utilizing absorption-edge characteristics between two kinds of X-ray targets without X-ray spectrometer. Actually, Cu and Ni targets are used with an inter-changeable system for elemental analysis of Fe 2O 3 particles and iron component in a mosquito larva.

  15. Structure of the Lassa Virus Nucleoprotein Revealed by X-ray Crystallography, Small-angle X-ray Scattering, and Electron Microscopy*

    PubMed Central

    Brunotte, Linda; Kerber, Romy; Shang, Weifeng; Hauer, Florian; Hass, Meike; Gabriel, Martin; Lelke, Michaela; Busch, Carola; Stark, Holger; Svergun, Dmitri I.; Betzel, Christian; Perbandt, Markus; Günther, Stephan

    2011-01-01

    The nucleoprotein (NP) of Lassa virus (LASV) strain AV was expressed in a recombinant baculovirus system. The crystal structure of full-length NP was solved at a resolution of 2.45 Å. The overall fold corresponds to that of NP of LASV strain Josiah (Qi, X., Lan, S., Wang, W., Schelde, L. M., Dong, H., Wallat, G. D., Ly, H., Liang, Y., and Dong, C. (2010) Nature 468, 779–783) with a root mean square deviation of 0.67 Å for all atoms (6.3% difference in primary sequence). As the packing in the crystal offers two different trimer architectures for the biological assembly, the quaternary structure of NP in solution was determined by small-angle x-ray scattering and EM. After classification and averaging of >6000 EM raw images, trimeric centrosymmetric structures were obtained, which correspond in size and shape to one trimer in the crystal structure formed around a crystallographic 3-fold rotation axis (symmetric trimer). The symmetric trimer is also a good model for the small-angle x-ray scattering data and could be well embedded into the ab initio model. The N-terminal domain of NP contains a deep nucleotide-binding cavity that has been proposed to bind cellular cap structures for priming viral mRNA synthesis. All residues implicated in m7GpppN binding were exchanged, and the transcription/replication phenotype of the NP mutant was tested using a LASV replicon system. None of the mutants showed a specific defect in mRNA expression; most were globally defective in RNA synthesis. In conclusion, we describe the full-length crystal structure and the quaternary structure in solution of LASV NP. The nucleotide-binding pocket of NP could not be assigned a specific role in viral mRNA synthesis. PMID:21917929

  16. Progress in high-resolution x-ray holographic microscopy

    SciTech Connect

    Jacobsen, C.; Kirz, J.; Howells, M.; McQuaid, K.; Rothman, S.; Feder, R.; Sayre, D.

    1987-07-01

    Among the various types of x-ray microscopes that have been demonstrated, the holographic microscope has had the largest gap between promise and performance. The difficulties of fabricating x-ray optical elements have led some to view holography as the most attractive method for obtaining the ultimate in high resolution x-ray micrographs; however, we know of no investigations prior to 1987 that clearly demonstrated submicron resolution in reconstructed images. Previous efforts suffered from problems such as limited resolution and dynamic range in the recording media, low coherent x-ray flux, and aberrations and diffraction limits in visible light reconstruction. We have addressed the recording limitations through the use of an undulator x-ray source and high-resolution photoresist recording media. For improved results in the readout and reconstruction steps, we have employed metal shadowing and transmission electron microscopy, along with numerical reconstruction techniques. We believe that this approach will allow holography to emerge as a practical method of high-resolution x-ray microscopy. 30 refs., 4 figs.

  17. Muscle cell membranes from early degeneration muscle cell fibers in Solenopsis are leaky to lanthanum: electron microscopy and X-ray analysis

    SciTech Connect

    Jones, R.G.; Davis, W.L.

    1985-06-01

    Lanthanum infusion techniques, transmission electron microscopy, and X-ray microanalysis were utilized to compare the permeability of muscle cell membranes from normal and degenerating muscle fibers of Solenopsis spp. In normal fibers, the electron-dense tracer was limited to components of the sarcotubular system. However, the insemination-induced degeneration of muscle fibers was characterized by the presence of an electron-dense precipitate within the myofibrils and mitochondria as well as in the extramyofibrillar spaces. The electron-dense material was subsequently identified by elemental analysis to be lanthanum. Such data indicate that one of the earliest stages of muscle degeneration involves an alteration in cell membrane permeability.

  18. The Reactivity and Structural Dynamics of Supported Metal Nanoclusters Using Electron Microscopy, in situ X-Ray Spectroscopy, Electronic Structure Theories, and Molecular Dynamics Simulations.

    SciTech Connect

    Judith C. Yang; Ralph G. Nuzzo, Duane Johnson, Anatoly Frenkel

    2008-07-01

    The distinguishing feature of our collaborative program of study is the focus it brings to emergent phenomena originating from the unique structural/electronic environments found in nanoscale materials. We exploit and develop frontier methods of atomic-scale materials characterization based on electron microscopy (Yang) and synchrotron X-ray absorption spectroscopy (Frenkel) that are in turn coupled innately with advanced first principles theory and methods of computational modeling (Johnson). In the past year we have made significant experimental advances that have led to important new understandings of the structural dynamics of what are unquestionably the most important classes of heterogeneous catalysts—the materials used to both produce and mitigate the consequences of the use of liquid hydrocarbon fuels.

  19. Exploring nanomagnetism with soft x-ray microscopy

    SciTech Connect

    Fischer, P.; Kim, D.-H.; Mesler, B.L.; Chao, W.; Sakdinawat,A.E.; Anderson, E.H.

    2006-10-30

    Magnetic soft X-ray microscopy images magnetism in nanoscale systems with a spatial resolution down to 15nm provided by state-of-the-art Fresnel zone plate optics. X-ray magnetic circular dichroism (X-MCD) is used as element-specific magnetic contrast mechanism similar to photoemission electron microscopy (PEEM), however, with volume sensitivity and the ability to record the images in varying applied magnetic fields which allows to study magnetization reversal processes at fundamental length scales. Utilizing a stroboscopic pump-probe scheme one can investigate fast spin dynamics with a time resolution down to 70 ps which gives access to precessional and relaxation phenomena as well as spin torque driven domain wall dynamics in nanoscale systems. Current developments in zone plate optics aim for a spatial resolution towards 10nm and at next generation X-ray sources a time resolution in the fsec regime can be envisioned.

  20. Cryogenic coherent X-ray diffraction imaging of biological samples at SACLA: a correlative approach with cryo-electron and light microscopy.

    PubMed

    Takayama, Yuki; Yonekura, Koji

    2016-03-01

    Coherent X-ray diffraction imaging at cryogenic temperature (cryo-CXDI) allows the analysis of internal structures of unstained, non-crystalline, whole biological samples in micrometre to sub-micrometre dimensions. Targets include cells and cell organelles. This approach involves preparing frozen-hydrated samples under controlled humidity, transferring the samples to a cryo-stage inside a vacuum chamber of a diffractometer, and then exposing the samples to coherent X-rays. Since 2012, cryo-coherent diffraction imaging (CDI) experiments have been carried out with the X-ray free-electron laser (XFEL) at the SPring-8 Ångstrom Compact free-electron LAser (SACLA) facility in Japan. Complementary use of cryo-electron microscopy and/or light microscopy is highly beneficial for both pre-checking samples and studying the integrity or nature of the sample. This article reports the authors' experience in cryo-XFEL-CDI of biological cells and organelles at SACLA, and describes an attempt towards reliable and higher-resolution reconstructions, including signal enhancement with strong scatterers and Patterson-search phasing. PMID:26919369

  1. Cryotomography x-ray microscopy state

    DOEpatents

    Le Gros, Mark; Larabell, Carolyn A.

    2010-10-26

    An x-ray microscope stage enables alignment of a sample about a rotation axis to enable three dimensional tomographic imaging of the sample using an x-ray microscope. A heat exchanger assembly provides cooled gas to a sample during x-ray microscopic imaging.

  2. X-ray microscopy of live biological micro-organisms

    NASA Astrophysics Data System (ADS)

    Raja Al-Ani, Ma'an Nassar

    Real-time, compact x-ray microscopy has the potential to benefit many scientific fields, including microbiology, pharmacology, organic chemistry, and physics. Single frame x-ray micro-radiography, produced by a compact, solid-state laser plasma source, allows scientists to use x-ray emission for elemental analysis, and to observe biological specimens in their natural state. In this study, x-ray images of mouse kidney tissue, live bacteria, Pseudomonas aeruginosa and Burkholderia cepacia, and the bacteria's interaction with the antibiotic gentamicin, are examined using x-ray microscopy. For the purposes of comparing between confocal microscopy and x-ray microscopy, we introduced to our work the technique of gold labeling. Indirect immunofluorescence staining and immuno-gold labeling were applied on human lymphocytes and human tumor cells. Differential interference contrast microscopy (DIC) showed the lymphocyte body and nucleus, as did x-ray microscopy. However, the high resolution of x-ray microscopy allows us to differentiate between the gold particles bound to the antibodies and the free gold. A compact, tabletop Nd: glass laser is used in this study to produce x-rays from an Yttrium target. An atomic force microscope is used to scan the x-ray images from the developed photo-resist. The use of compact, tabletop laser plasma sources, in conjunction with x-ray microscopy, is a new technique that has great potential as a flexible, user-friendly scientific research tool.

  3. Synchrotron X-ray Enhanced Scanning Tunneling Microscopy

    NASA Astrophysics Data System (ADS)

    Rose, Volker; Freeland, John

    2011-03-01

    Proper understanding of complex phenomena occurring in nanostructures requires tools with both the ability to resolve the nanometer scale as well as provide detailed information about chemical, electronic, and magnetic structure. Scanning tunneling microscopy (STM) achieves the requisite high spatial resolution; however, direct elemental determination is not easily accomplished. X-ray microscopies, on the other hand, provide elemental selectivity, but currently have spatial resolution only of tens of nanometers. We present a novel and radically different concept that employs detection of local synchrotron x-ray interactions utilizing a STM that provides spatial resolution, and x-ray absorption directly yields chemical, electronic, and magnetic sensitivity. If during tunneling the sample is simultaneously illuminated with monochromatic x-rays, characteristic absorption will arise. Electrons that are excited into unoccupied levels close to the Fermi level modulate the tunneling current giving rise to elemental contrast. This work was supported by the U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract DE-AC02-06CH11357.

  4. ANALYSIS OF THE MICROBIOLOGICAL PARTICULATES IN MUNICIPAL DRINKING-WATER BY SCANNING ELECTRON MICROSCOPY/X-RAY ENERGY SPECTROSCOPY (ANALYSE VON BIOLOGISCHEN PARTIKELN IM TRINKWASSER DURCH RASTERELEKTRONEN-MIKROSKOPIE UND ELEKTRONENSTRAHLMIKROANALYSE)

    EPA Science Inventory

    Scanning electron microscopy and X-ray energy spectroscopy (SEM/XES) were used to survey the biological and nonbiological particles in two different municipal drinking-water systems. Microbiological particles could be differentiated from nonbiological by their qualitative element...

  5. Effects of the environmental factors on the casein micelle structure studied by cryo transmission electron microscopy and small-angle x-ray scattering/ultrasmall-angle x-ray scattering

    NASA Astrophysics Data System (ADS)

    Marchin, Stéphane; Putaux, Jean-Luc; Pignon, Frédéric; Léonil, Joëlle

    2007-01-01

    Casein micelles are colloidal protein-calcium-transport complexes whose structure has not been unequivocally elucidated. This study used small-angle x-ray scattering (SAXS) and ultrasmall angle x-ray scattering (USAXS) as well as cryo transmission electron microscopy (cryo-TEM) to provide fine structural details on their structure. Cryo-TEM observations of native casein micelles fractionated by differential centrifugation showed that colloidal calcium phosphate appeared as nanoclusters with a diameter of about 2.5nm. They were uniformly distributed in a homogeneous tangled web of caseins and were primarily responsible for the intensity distribution in the SAXS profiles at the highest q vectors corresponding to the internal structure of the casein micelles. A specific demineralization of casein micelles by decreasing the pH from 6.7 to 5.2 resulted in a reduced granular aspect of the micelles observed by cryo-TEM and the existence of a characteristic point of inflection in SAXS profiles. This supports the hypothesis that the smaller substructures detected by SAXS are colloidal calcium phosphate nanoclusters rather than putative submicelles.

  6. Rigorous quantitative elemental microanalysis by scanning electron microscopy/energy dispersive x-ray spectrometry (SEM/EDS) with spectrum processing by NIST DTSA-II

    NASA Astrophysics Data System (ADS)

    Newbury, Dale E.; Ritchie, Nicholas W. M.

    2014-09-01

    Quantitative electron-excited x-ray microanalysis by scanning electron microscopy/silicon drift detector energy dispersive x-ray spectrometry (SEM/SDD-EDS) is capable of achieving high accuracy and high precision equivalent to that of the high spectral resolution wavelength dispersive x-ray spectrometer even when severe peak interference occurs. The throughput of the SDD-EDS enables high count spectra to be measured that are stable in calibration and resolution (peak shape) across the full deadtime range. With this high spectral stability, multiple linear least squares peak fitting is successful for separating overlapping peaks and spectral background. Careful specimen preparation is necessary to remove topography on unknowns and standards. The standards-based matrix correction procedure embedded in the NIST DTSA-II software engine returns quantitative results supported by a complete error budget, including estimates of the uncertainties from measurement statistics and from the physical basis of the matrix corrections. NIST DTSA-II is available free for Java-platforms at: http://www.cstl.nist.gov/div837/837.02/epq/dtsa2/index.html).

  7. Faradaurate-940: synthesis, mass spectrometry, electron microscopy, high-energy X-ray diffraction, and X-ray scattering study of Au∼940±20(SR)∼160±4 nanocrystals.

    PubMed

    Kumara, Chanaka; Zuo, Xiaobing; Cullen, David A; Dass, Amala

    2014-06-24

    Obtaining monodisperse nanocrystals and determining their composition to the atomic level and their atomic structure is highly desirable but is generally lacking. Here, we report the discovery and comprehensive characterization of a 2.9 nm plasmonic nanocrystal with a composition of Au940±20(SCH2CH2Ph)160±4, which is the largest mass spectrometrically characterized gold thiolate nanoparticle produced to date. The compositional assignment has been made using electrospray ionization and matrix-assisted laser desorption ionization mass spectrometry (MS). The MS results show an unprecedented size monodispersity, where the number of Au atoms varies by only 40 atoms (940 ± 20). The mass spectrometrically determined composition and size are supported by aberration-corrected scanning transmission electron microscopy (STEM) and synchrotron-based methods such as atomic pair distribution function (PDF) and small-angle X-ray scattering (SAXS). Lower-resolution STEM images show an ensemble of particles-1000s per frame-visually demonstrating monodispersity. Modeling of SAXS data on statistically significant nanoparticle population-approximately 10(12) individual nanoparticles-shows that the diameter is 3.0 ± 0.2 nm, supporting mass spectrometry and electron microscopy results on monodispersity. Atomic PDF based on high-energy X-ray diffraction experiments shows decent match with either a Marks decahedral or truncated octahedral structure. Atomic resolution STEM images of single particles and their fast Fourier transform suggest face-centered cubic arrangement. UV-visible spectroscopy data show that Faradaurate-940 supports a surface plasmon resonance peak at ̃505 nm. These monodisperse plasmonic nanoparticles minimize averaging effects and have potential application in solar cells, nano-optical devices, catalysis, and drug delivery. PMID:24813022

  8. X-ray holographic microscopy: Improved images of zymogen granules

    SciTech Connect

    Jacobsen, C.; Howells, M.; Kirz, J.; McQuaid, K.; Rothman, S.

    1988-10-01

    Soft x-ray holography has long been considered as a technique for x-ray microscopy. It has been only recently, however, that sub-micron resolution has been obtained in x-ray holography. This paper will concentrate on recent progress we have made in obtaining reconstructed images of improved quality. 15 refs., 6 figs.

  9. Stimulated Electronic X-Ray Raman Scattering

    NASA Astrophysics Data System (ADS)

    Weninger, Clemens; Purvis, Michael; Ryan, Duncan; London, Richard A.; Bozek, John D.; Bostedt, Christoph; Graf, Alexander; Brown, Gregory; Rocca, Jorge J.; Rohringer, Nina

    2013-12-01

    We demonstrate strong stimulated inelastic x-ray scattering by resonantly exciting a dense gas target of neon with femtosecond, high-intensity x-ray pulses from an x-ray free-electron laser (XFEL). A small number of lower energy XFEL seed photons drive an avalanche of stimulated resonant inelastic x-ray scattering processes that amplify the Raman scattering signal by several orders of magnitude until it reaches saturation. Despite the large overall spectral width, the internal spiky structure of the XFEL spectrum determines the energy resolution of the scattering process in a statistical sense. This is demonstrated by observing a stochastic line shift of the inelastically scattered x-ray radiation. In conjunction with statistical methods, XFELs can be used for stimulated resonant inelastic x-ray scattering, with spectral resolution smaller than the natural width of the core-excited, intermediate state.

  10. Functional biocompatible magnetite-cellulose nanocomposite fibrous networks: Characterization by fourier transformed infrared spectroscopy, X-ray powder diffraction and field emission scanning electron microscopy analysis

    NASA Astrophysics Data System (ADS)

    Habibi, Neda

    2015-02-01

    The preparation and characterization of functional biocompatible magnetite-cellulose nano-composite fibrous material is described. Magnetite-cellulose nano-composite was prepared by a combination of the solution-based formation of magnetic nano-particles and subsequent coating with amino celluloses. Characterization was accomplished using X-ray powder diffraction (XRD), fourier transformed infrared (FTIR) and field emission scanning electron microscopy (FESEM) analysis. The peaks of Fe3O4 in the XRD pattern of nanocomposite confirm existence of the nanoparticles in the amino cellulose matrix. Magnetite-cellulose particles exhibit an average diameter of roughly 33 nm as demonstrated by field emission scanning electron microscopy. Magnetite nanoparticles were irregular spheres dispersed in the cellulose matrix. The vibration corresponding to the Nsbnd CH3 functional group about 2850 cm-1 is assigned in the FTIR spectra. Functionalized magnetite-cellulose nano-composite polymers have a potential range of application as targeted drug delivery system in biomedical field.

  11. Green synthesis and characterization of Carica papaya leaf extract coated silver nanoparticles through X-ray diffraction, electron microscopy and evaluation of bactericidal properties.

    PubMed

    Banala, Rajkiran Reddy; Nagati, Veera Babu; Karnati, Pratap Reddy

    2015-09-01

    The evolution of nanotechnology and the production of nanomedicine from various sources had proven to be of intense value in the field of biomedicine. The smaller size of nanoparticles is gaining importance in research for the treatment of various diseases. Moreover the production of nanoparticles is eco-friendly and cost effective. In the present study silver nanoparticles were synthesized from Carica papaya leaf extract (CPL) and characterized for their size and shape using scanning electron microscopy and transmission electron microscopy, respectively. Fourier transform infrared spectroscopy (FTIR), Energy dispersive X-ray spectroscopy (EDS/EDX) and X-ray diffraction spectroscopy (XRD) were conducted to determine the concentration of metal ions, the shape of molecules. The bactericidal activity was evaluated using Luria Bertani broth cultures and the minimum inhibition concentration (MIC) and minimum bactericidal concentration (MBC) were estimated using turbidimetry. The data analysis showed size of 50-250 nm spherical shaped nanoparticles. The turbidimetry analysis showed MIC and MBC was >25 μg/mL against both Gram positive and Gram negative bacteria in Luria Bertani broth cultures. In summary the synthesized silver nanoparticles from CPL showed acceptable size and shape of nanoparticles and effective bactericidal activity. PMID:26288570

  12. Green synthesis and characterization of Carica papaya leaf extract coated silver nanoparticles through X-ray diffraction, electron microscopy and evaluation of bactericidal properties

    PubMed Central

    Banala, Rajkiran Reddy; Nagati, Veera Babu; Karnati, Pratap Reddy

    2015-01-01

    The evolution of nanotechnology and the production of nanomedicine from various sources had proven to be of intense value in the field of biomedicine. The smaller size of nanoparticles is gaining importance in research for the treatment of various diseases. Moreover the production of nanoparticles is eco-friendly and cost effective. In the present study silver nanoparticles were synthesized from Carica papaya leaf extract (CPL) and characterized for their size and shape using scanning electron microscopy and transmission electron microscopy, respectively. Fourier transform infrared spectroscopy (FTIR), Energy dispersive X-ray spectroscopy (EDS/EDX) and X-ray diffraction spectroscopy (XRD) were conducted to determine the concentration of metal ions, the shape of molecules. The bactericidal activity was evaluated using Luria Bertani broth cultures and the minimum inhibition concentration (MIC) and minimum bactericidal concentration (MBC) were estimated using turbidimetry. The data analysis showed size of 50–250 nm spherical shaped nanoparticles. The turbidimetry analysis showed MIC and MBC was >25 μg/mL against both Gram positive and Gram negative bacteria in Luria Bertani broth cultures. In summary the synthesized silver nanoparticles from CPL showed acceptable size and shape of nanoparticles and effective bactericidal activity. PMID:26288570

  13. Analysis of passivated A-286 stainless steel surfaces for mass spectrometer inlet systems by Auger electron and X-ray photoelectron spectroscopy and scanning electron microscopy

    SciTech Connect

    Ajo, Henry; Blankenship, Donnie; Clark, Elliot

    2014-07-25

    In this study, various commercially available surface treatments are being explored for use on stainless steel components in mass spectrometer inlet systems. Type A-286 stainless steel coupons, approximately 12.5 mm in diameter and 3 mm thick, were passivated with one of five different surface treatments; an untreated coupon served as a control. The surface and near-surface microstructure and chemistry of the coupons were investigated using sputter depth profiling using Auger electron spectroscopy, x-ray photoelectron spectroscopy, and scanning electron microscopy (SEM). All the surface treatments studied appeared to change the surface morphology dramatically, as evidenced by lack of tool marks on the treated samples in SEM images. In terms of the passivation treatment, Vendors A-D appeared to have oxide layers that were very similar in thickness to each other (0.7–0.9 nm thick), as well as to the untreated samples (the untreated sample oxide layers appeared to be somewhat larger). Vendor E’s silicon coating appears to be on the order of 200 nm thick.

  14. Analysis of passivated A-286 stainless steel surfaces for mass spectrometer inlet systems by Auger electron and X-ray photoelectron spectroscopy and scanning electron microscopy

    DOE PAGESBeta

    Ajo, Henry; Blankenship, Donnie; Clark, Elliot

    2014-07-25

    In this study, various commercially available surface treatments are being explored for use on stainless steel components in mass spectrometer inlet systems. Type A-286 stainless steel coupons, approximately 12.5 mm in diameter and 3 mm thick, were passivated with one of five different surface treatments; an untreated coupon served as a control. The surface and near-surface microstructure and chemistry of the coupons were investigated using sputter depth profiling using Auger electron spectroscopy, x-ray photoelectron spectroscopy, and scanning electron microscopy (SEM). All the surface treatments studied appeared to change the surface morphology dramatically, as evidenced by lack of tool marks onmore » the treated samples in SEM images. In terms of the passivation treatment, Vendors A-D appeared to have oxide layers that were very similar in thickness to each other (0.7–0.9 nm thick), as well as to the untreated samples (the untreated sample oxide layers appeared to be somewhat larger). Vendor E’s silicon coating appears to be on the order of 200 nm thick.« less

  15. Soft x-ray holography and microscopy of biological cells

    NASA Astrophysics Data System (ADS)

    Chen, Jianwen; Gao, Hongyi; Xie, Honglan; Li, Ruxin; Xu, Zhizhan

    2003-10-01

    Some experimental results on soft X-ray microscopy and holography imaging of biological specimens are presented in the paper. As we know, due to diffraction effects, there exists a resolution limit determined by wavelength λ and numerical aperture NA in conventional optical microscopy. In order to improve resolution, the num erical aperture should be made as large as possible and the wavelength as short as possible. Owing to the shorter wavelength, X-rays provide the potential of higher resolution in X-ray microscopy, holography image and allow for exam ination the interior structures of thicker specimens. In the experiments, we used synchrotron radiation source in Hefei as light source. Soft X-rays come from a bending magnet in 800 M eV electron storage ring with characteristic wavelength of 2.4 nm. The continuous X-ray spectrums are monochromatized by a zone-plate and a pinhole with 300 m diameter. The experimental set-up is typical contact microscopic system, its main advantage is simplicity and no special optical element is needed. The specimens used in the experiments of microscopic imaging are the colibacillus, the gingko vascular hundle and the fritillaries ovary karyon. The specimen for holographic imaging is the spider filam ents. The basic structures of plant cells such as the cell walls, the cytoplasm and the karyon especially the joint structures between the cells are observed clearly. An experimental study on a thick biological specimen that is a whole sporule w ith the thickness of about 30 μm is performed. In the holographic experiments, the experimental setup is typical Gabor in-line holography. The specimen is placed in line with X-ray source, which provides both the reference w aves and specimen illum ination. The specimen is some spider filament, which adhere to a Si3N4 film. The recording medium is PM M A, which is placed at recording distance of about 400 μm from the specimen. The hologram s were reconstructed by digital method with 300 nm

  16. X-ray magnetic circular dichroism photoemission electron microscopy of focused ion beam-induced magnetic patterns on iron-rhodium surfaces

    NASA Astrophysics Data System (ADS)

    Tohki, Atsushi; Aikoh, Kazuma; Shinoda, Ryoichi; Ohkochi, Takuo; Kotsugi, Masato; Nakamura, Tetsuya; Kinoshita, Toyohiko; Iwase, Akihiro; Matsui, Toshiyuki

    2013-05-01

    Iron-rhodium (FeRh) thin films were irradiated with a 30 keV Ga ion beam using a focused ion beam system to produce micrometer scale ferromagnetic square dot arrays. Two-dimensional magnetic square dot arrays with dimensions of 30 × 30, 10 × 10, and 5 × 5 μm were successfully produced on the FeRh surface, which was confirmed by magnetic force microscopy. The results of photoemission electron microscopy combined with X-ray magnetic circular dichroism revealed that the magnetization of the magnetic square dots could be controlled by changing the amount of irradiation. The magnetic domain structure of the magnetic square dots with sides of 5-30 μm was found to be a single domain structure, which was possibly influenced by the interaction between ferromagnetic and antiferromagnetic interfaces.

  17. Exceptional case of bone resorption in an osteo-odonto-keratoprosthesis. A scanning electron microscopy and X-ray microanalysis study.

    PubMed

    Caiazza, S; Falcinelli, G; Pintucci, S

    1990-01-01

    This article reports the findings of investigations on an osteo-odonto-keratoprosthesis in an eye that was enucleated owing to severe complications 12 years after implantation. Scanning electron microscopy and electron probe X-ray microanalysis showed extensive resorption of the bone that was used as a supporting element in the kind of transcorneal prosthesis developed by Strampelli. The destructive process, in addition to surgical trauma, has been associated with the early and recurrent bacterial infections relating to the presence of Staphylococcus epidermidis. The need to control the occurrence of primary bacterial infections in traumatized tissues during operations as well as further infectious situations, given the enhanced antibiotic-resistence of bacteria, is emphasized. PMID:2297990

  18. Imaging bacterial spores by soft-x-ray microscopy

    SciTech Connect

    Stead, A.D.; Ford, T.W.; Judge, J.

    1997-04-01

    Bacterial spores are able to survive dehydration, but neither the physiological nor structural basis of this have been fully elucidated. Furthermore, once hydrated, spores often require activation before they will germinate. Several treatments can be used to activate spores, but in the case of Bacillus subtlis the most effective is heat treatment. The physiological mechanism associated with activation is also not understood, but some workers suggest that the loss of calcium from the spores may be critical. However, just prior to germination, the spores change from being phase bright to phase dark when viewed by light microscopy. Imaging spores by soft x-ray microscopy is possible without fixation. Thus, in contrast to electron microscopy, it is possible to compare the structure of dehydrated and hydrated spores in a manner not possible previously. A further advantage is that it is possible to monitor individual spores by phase contrast light microscopy immediately prior to imaging with soft x-rays; whereas, with both electron microscopy and biochemical studies, it is a population of spores being studied without knowledge of the phase characteristics of individual spores. This study has therefore tried to compare dehydrated and hydrated spores and to determine if there is a mass loss from individual spores as they pass the transition from being phase bright to phase dark.

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

    NASA Astrophysics Data System (ADS)

    Geng, Hong; Kang, Sujin; Jung, Hae-Jin; ChoëL, Marie; Kim, Hyekyeong; Ro, Chul-Un

    2010-08-01

    For the last decade the Monte Carlo calculation method has been proven to be an excellent tool for accurately simulating electron-solid interactions in atmospheric individual particles of micrometer size. Although it was designed for application to scanning electron microscopy, in the present study it is demonstrated that the Monte Carlo calculation can also be applied in a quantitative single particle analysis using transmission electron microscopy (TEM) with an ultrathin window energy-dispersive X-ray (EDX) spectrometer with a high accelerating voltage (200 kV). By utilizing an iterative reverse Monte Carlo simulation combined with successive approximation, atomic elemental concentrations (including low-Z elements) of submicrometer standard particles were determined with high accuracy for electron beam refractory particles such as NaCl, KCl, SiO2, Fe2O3, Na2SO4, K2SO4, CaCO3, and CaSO4. On the basis of quantitative X-ray analysis together with morphological information from TEM images, overall 1638 submicrometer individual particles from 10 sets of aerosol samples collected in Incheon, Korea, were identified. The most frequently encountered particle types are carbonaceous and (NH4)2SO4/NH4HSO4-containing particles, followed by mineral (e.g., aluminosilicate, SiO2, CaCO3), sea salt, K-rich (e.g., K2SO4 and KCl), Fe-rich, fly ash, and transition or heavy-metal-containing (e.g., ZnSO4, ZnCl2, PbSO4) particles. The relative abundances of the submicrometer particle types vary among samples collected in different seasons and also depend on different air mass transport routes. This study demonstrates that the quantitative TEM-EDX individual particle analysis is a useful and reliable technique in characterizing urban submicrometer aerosol particles.

  20. Basal ganglia calcification induced by excitotoxicity: an experimental model characterised by electron microscopy and X-ray microanalysis.

    PubMed

    Mahy, N; Prats, A; Riveros, A; Andrés, N; Bernal, F

    1999-09-01

    Activation of glutamate receptors induces an excitotoxic neurodegenerative process characterised in some brain areas by the formation of calcium precipitates. To examine the pathogenesis of basal ganglia calcification (BGC), an improved procedure of X-ray microanalysis was used to study experimental excitotoxic calcification in the rat. Three weeks after injection of ibotenic acid (IBO) in the rat basal forebrain, calcified inclusions within hypertrophied astrocytes were characterised. They appeared to form part of a filamentous structure localised in the cytoplasm in association with normal mitochondria and other organelles. Larger inclusions were surrounded by reactive microglia. The main inorganic components in these deposits were Ca and P, frequently accompanied by S. Al, Si and K. The shape and Ca/P molar ratio of the large deposits (>10 microm) indicate that they may be biological apatites. Aluminosilicates were detected as small deposits (<4 microm) free of other mineral constituents. To our knowledge this is the first report showing that IBO lesion induces brain accumulation of aluminosilicates similar to that described in Alzheimer's or Fahr's patients. Our data indicate that precipitation of Ca and Al may reduce their IBO-induced increased concentration. In conclusion, the experimental model and the improved efficiency of X-ray analysis described may help us to understand the pathogenesis of BGC. PMID:10483777

  1. Direct comparison between X-ray nanotomography and scanning electron microscopy for the microstructure characterization of a solid oxide fuel cell anode

    SciTech Connect

    Quey, R.; Suhonen, H.; Laurencin, J.; Cloetens, P.; Bleuet, P.

    2013-04-15

    X-ray computed nanotomography (nano-CT) and scanning electron microscopy (SEM) have been applied to characterize the microstructure of a Solid Oxide Fuel Cell (SOFC) anode. A direct comparison between the results of both methods is conducted on the same region of the microstructure to assess the spatial resolution of the nano-CT microstructure, SEM being taken as a reference. A registration procedure is proposed to find out the position of the SEM image within the nano-CT volume. It involves a second SEM observation, which is taken along an orthogonal direction and gives an estimate reference SEM image position, which is then refined by an automated optimization procedure. This enables an unbiased comparison between the cell porosity morphologies provided by both methods. In the present experiment, nano-CT is shown to underestimate the number of pores smaller than 1 μm and overestimate the size of the pores larger than 1.5 μm. - Highlights: ► X-ray computed nanotomography (nano-CT) and SEM are used to characterize an SOFC anode. ► A methodology is proposed to compare the nano-CT and SEM data on the same region. ► The spatial resolution of the nano-CT data is assessed from that comparison.

  2. A simple method for detection of gunshot residue particles from hands, hair, face, and clothing using scanning electron microscopy/wavelength dispersive X-ray (SEM/WDX).

    PubMed

    Kage, S; Kudo, K; Kaizoji, A; Ryumoto, J; Ikeda, H; Ikeda, N

    2001-07-01

    We devised a simple and rapid method for detection of gunshot residue (GSR) particles, using scanning electron microscopy/wavelength dispersive X-ray (SEM/WDX) analysis. Experiments were done on samples containing GSR particles obtained from hands, hair, face, and clothing, using double-sided adhesive coated aluminum stubs (tape-lift method). SEM/WDX analyses for GSR were carried out in three steps: the first step was map analysis for barium (Ba) to search for GSR particles from lead styphnate primed ammunition, or tin (Sn) to search for GSR particles from mercury fulminate primed ammunition. The second step was determination of the location of GSR particles by X-ray imaging of Ba or Sn at a magnification of x 1000-2000 in the SEM, using data of map analysis, and the third step was identification of GSR particles, using WDX spectrometers. Analysis of samples from each primer of a stub took about 3 h. Practical applications were shown for utility of this method. PMID:11451063

  3. Remineralization of demineralized enamel by toothpastes: a scanning electron microscopy, energy dispersive X-ray analysis, and three-dimensional stereo-micrographic study.

    PubMed

    Gjorgievska, Elizabeta S; Nicholson, John W; Slipper, Ian J; Stevanovic, Marija M

    2013-06-01

    Remineralization of hard dental tissues is thought to be a tool that could close the gap between prevention and surgical procedures in clinical dentistry. The purpose of this study was to examine the remineralizing potential of different toothpaste formulations: toothpastes containing bioactive glass, hydroxyapatite, or strontium acetate with fluoride, when applied to demineralized enamel. Results obtained by scanning electron microscopy (SEM) and SEM/energy dispersive X-ray analyses proved that the hydroxyapatite and bioactive glass-containing toothpastes were highly efficient in promoting enamel remineralization by formation of deposits and a protective layer on the surface of the demineralized enamel, whereas the toothpaste containing 8% strontium acetate and 1040 ppm fluoride as NaF had little, if any, remineralization potential. In conclusion, the treatment of demineralized teeth with toothpastes containing hydroxyapatite or bioactive glass resulted in repair of the damaged tissue. PMID:23659606

  4. Microstructural Investigation of SexTe100-x Thin Films Deposited on Si(100) Substrates by X-ray Diffractometer and Transmission Electron Microscopy Analysis

    NASA Astrophysics Data System (ADS)

    Kim, Eun Tae; Lee, Jeong Yong; Kim, Yong Tae

    2007-11-01

    The microstructural properties of SexTe100-x (x=16,29,38) thin films are investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM) analysis. SexTe100-x thin films have a Te hexagonal structure and Te{011} interplanar spacing decreases because some Se atoms occupy Te atomic sites, forming Se helical chains within the Te helical chains. By increasing the Se contents from 16 to 29 at. %, Se5.95Te1.05 monoclinic and Se hexagonal structures coexist in a grain and at 38 at. %, a Se hexagonal structure is observed within the Te hexagonal grain. This means that SexTe100-x thin films maintain the Te hexagonal structure and that phase separation does not occur owing to the short diffusion time.

  5. Electronic structure of ZnO nanorods studied by angle-dependent x-ray absorption spectroscopy and scanning photoelectron microscopy

    NASA Astrophysics Data System (ADS)

    Chiou, J. W.; Jan, J. C.; Tsai, H. M.; Bao, C. W.; Pong, W. F.; Tsai, M.-H.; Hong, I.-H.; Klauser, R.; Lee, J. F.; Wu, J. J.; Liu, S. C.

    2004-05-01

    Angle-dependent x-ray absorption near-edge structure (XANES) and scanning photoelectron microscopy measurements were performed to differentiate local electronic structures at the tips and sidewalls of highly aligned ZnO nanorods. The overall intensity of the O K-edge XANES spectra is greatly enhanced for small photon incident angles. In contrast, the overall intensity of the Zn K-edge XANES is much less sensitive to the photon incident angle. Both valence-band photoemission and O K-edge XANES spectra show substantial enhancement of O 2p derived states near the valence band maximum and conduction band minimum, respectively. The spatially resolved Zn 3d core level spectra from tip and sidewall regions show the lack of chemical shift. All the results consistently suggest that the tip surfaces of the highly aligned ZnO nanorods are terminated by O ions and the nanorods are oriented in the [0001¯] direction.

  6. Hard x-ray Zernike microscopy reaches 30 nm resolution.

    SciTech Connect

    Chen, Y.; Chen, T.; Yi, J.; Chu, Y.; Lee, W.-K.; Wang, C.; Kempson, I.; Hwu, Y.; Gajdosik, V.; Margaritondo, G.

    2011-03-30

    Since its invention in 1930, Zernike phase contrast has been a pillar in optical microscopy and more recently in x-ray microscopy, in particular for low-absorption-contrast biological specimens. We experimentally demonstrate that hard-x-ray Zernike microscopy now reaches a lateral resolution below 30?nm while strongly enhancing the contrast, thus opening many new research opportunities in biomedicine and materials science.

  7. Hard x-ray Zernike Microscopy Reaches 30 nm Resolution

    SciTech Connect

    Chen, Y.T.; Chu, Y.; Chen, T-Y.; Yi, J.; Lee, W-K.; Wang, C-L.; Kempson, I. M.; Hwu, Y.; Gajdosik, V.; Margaritondo, G.

    2011-03-30

    Since its invention in 1930, Zernike phase contrast has been a pillar in optical microscopy and more recently in x-ray microscopy, in particular for low-absorption-contrast biological specimens. We experimentally demonstrate that hard-x-ray Zernike microscopy now reaches a lateral resolution below 30 nm while strongly enhancing the contrast, thus opening many new research opportunities in biomedicine and materials science.

  8. X-ray laser microscopy of rat sperm nuclei

    SciTech Connect

    Da Silva, L.B. ); Trebes, J.E.; Balhorn, R.; Mrowka, S.; Barbee, T.W.Jr.; Brase, J.; Corzett, M.; Koch, J.A.; Lee, C.; London, R.A.; MacGowan, B.J.; Matthews, D.L.; Stone, G. ); Anderson, E.; Attwood, D.T. ); Gray, J. ); Kern, D. )

    1992-10-09

    The development of high brightness and short pulse width x-ray lasers now offers biologists the possibility of high-resolution imaging of specimens in an aqueous environment without the blurring effects associated with natural motions and chemical erosion. As a step toward developing the capabilities of this type of x-ray microscopy, a tantalum x-ray laser at 44.83 angstrom wavelength was used together with an x-ray zone plate lens to image both unlabeled and selectively gold-labeled dried rat sperm nuclei. The observed images show {approximately}500 angstrom features, illustrate the importance of x-ray microscopy in determining chemical composition, and provide information about the uniformity of sperm chromatin organization and the extent of sperm chromatin hydration.

  9. The Scanning X-Ray Microprobe at the Esrf ``X-Ray Microscopy'' Beamline

    NASA Astrophysics Data System (ADS)

    Susini, J.; Salomé, M.; Fayard, B.; Ortega, R.; Kaulich, B.

    The development of high brilliance X-ray sources coupled with advances in manufacturing technologies of focusing optics has led to significant improvements in submicrometer probes for spectroscopy, diffraction and imaging applications. For instance, X-ray microscopy in the 1-10 keV energy range is better-suited for analyzing trace elements in fluorescence yield. This article will be biased towards submicron fluorescence microscopy developed on the ID21 beamline at the ESRF. The main technical developments, involving new focusing lenses or novel phase contrast method, are presented. Strengths and weaknesses of X-ray microscopy and spectromicroscopy techniques are discussed and illustrated by examples in biology, materials science and geology.

  10. Development of Cell Staining Technique for X-Ray Microscopy

    SciTech Connect

    Tseng, P. Y.; Shih, Y. T.; Liu, C. J.; Hsu, T.; Chien, C. C.; Leng, W. H.; Liang, K. S.; Yin, G. C.; Chen, F. R.; Je, J. H.; Margaritondo, G.; Hwu, Y.

    2007-01-19

    We report a technique for detection of sub-cellular organelles and proteins with hard x-ray microscopy. Several metals were used for enhancing contrast for x-ray microscopy. Osmium tetroxide provides an excellent stain for lipid and can delineate cell membrane. Uranyl acetate has high affinity for nucleotide and can stain nucleus. Immunolocalization of specific proteins and sub-cellular organelles was achieved by 3'3 diaminobenzidine (DAB) with nickel enhancement and nanogold-conjugated secondary antibody with silver enhancement. The x-rays emitted from synchrotron source was monochromatized by double crystal monochromator, the photon energy was fixed at 8 keV to optimize the focusing efficiency of the zone plates. The estimated resolution is about 60 nm. When compared with visible light and conventional confocal microscopy, the X-ray microscopy provides a superior resolution to both conventional optical microscopes.

  11. Scanning electron microscopy coupled with energy-dispersive X-ray spectrometry for quick detection of sulfur-oxidizing bacteria in environmental water samples

    NASA Astrophysics Data System (ADS)

    Sun, Chengjun; Jiang, Fenghua; Gao, Wei; Li, Xiaoyun; Yu, Yanzhen; Yin, Xiaofei; Wang, Yong; Ding, Haibing

    2016-03-01

    Detection of sulfur-oxidizing bacteria has largely been dependent on targeted gene sequencing technology or traditional cell cultivation, which usually takes from days to months to carry out. This clearly does not meet the requirements of analysis for time-sensitive samples and/or complicated environmental samples. Since energy-dispersive X-ray spectrometry (EDS) can be used to simultaneously detect multiple elements in a sample, including sulfur, with minimal sample treatment, this technology was applied to detect sulfur-oxidizing bacteria using their high sulfur content within the cell. This article describes the application of scanning electron microscopy imaging coupled with EDS mapping for quick detection of sulfur oxidizers in contaminated environmental water samples, with minimal sample handling. Scanning electron microscopy imaging revealed the existence of dense granules within the bacterial cells, while EDS identified large amounts of sulfur within them. EDS mapping localized the sulfur to these granules. Subsequent 16S rRNA gene sequencing showed that the bacteria detected in our samples belonged to the genus Chromatium, which are sulfur oxidizers. Thus, EDS mapping made it possible to identify sulfur oxidizers in environmental samples based on localized sulfur within their cells, within a short time (within 24 h of sampling). This technique has wide ranging applications for detection of sulfur bacteria in environmental water samples.

  12. Scanning electron and atomic force microscopy, and raman and x-ray photoelectron spectroscopy characterization of near-isogenic soft and hard wheat kernels and corresponding flours

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Atomic force microscopy (AFM), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) are used to investigate vitreous (hard) and non-vitreous (soft) wheat kernels and their corresponding wheat flours. AFM data reveal two different microstructures. The vitreous kernel reveals a granular text...

  13. X-ray microscopy study of bone mineralization

    NASA Astrophysics Data System (ADS)

    Salomé, M.; Lafage-Proust, M. H.; Vico, L.; Amblard, D.; Kaulich, B.; Oestreich, S.; Susini, J.; Barrett, R.

    2000-05-01

    Transmission spectro-microscopy around the calcium K-edge and fluorescence microscopy were performed respectively on the Transmission X-ray Microscope (TXM) and Scanning X-ray Microscope (SXM) end-stations of ID21 beamline at ESRF, to map the calcium distribution and the Ca/P ratio in bone samples. Preliminary results are presented. The motivation for these experiments is the study of the genetic determinism of bone mineralisation parameters in two different strains of mice.

  14. Use of SIMS microscopy and electron probe X-ray microanalysis to study the subcellular localization of aluminium in Vicia faba roots cells.

    PubMed

    Mangabeira, P; Mushrifah, I; Escaig, F; Laffray, D; França, M G; Galle, P

    1999-06-01

    Received January 4, 1999; Accepted March 25, 1999 Secondary ion mass spectrometry (SIMS), electron probe X-ray microanalysis (EPMA) and transmission electron microscopy (TEM) were used to study the tissular distribution and subcellular localization of aluminium (Al) precipitate in roots of Viciafaba. The broad bean plant, grown in nitrate solution with 193 microM Al3+ at pH 4.8, for 15 days showed Al deposits in the roots. Al accumulation was not detected in the stems nor in the leaves. Al was found mainly localized on the root's surfaces and within the cell walls of the cortical cells. Al signal was not detected in the vascular tissues. Two weeks exposure to Al caused ultrastructural changes in cortical cells and sometimes a complete disruption of these cells. Deposition of Al in form of insoluble complexes associated with phosphorus, appeared as electron opaque materials in the vacuoles of disrupted cortex cells and in the intercellular inclusions. The leaves turned yellowish at the end of 15 days exposure. The use of electron microprobe, to investigate the same tissues as the ones investigated by SIMS, provided complementary results on aluminium allocation. PMID:10432188

  15. Refractive Optics for Hard X-ray Transmission Microscopy

    SciTech Connect

    Simon, M.; Last, A.; Mohr, J.; Nazmov, V.; Reznikova, E.; Ahrens, G.; Voigt, A.

    2011-09-09

    For hard x-ray transmission microscopy at photon energies higher than 15 keV we design refractive condenser and imaging elements to be used with synchrotron light sources as well as with x-ray tube sources. The condenser lenses are optimized for low x-ray attenuation--resulting in apertures greater than 1 mm--and homogeneous intensity distribution on the detector plane, whereas the imaging enables high-resolution (<100 nm) full-field imaging. To obtain high image quality at reasonable exposure times, custom-tailored matched pairs of condenser and imaging lenses are being developed. The imaging lenses (compound refractive lenses, CRLs) are made of SU-8 negative resist by deep x-ray lithography. SU-8 shows high radiation stability. The fabrication technique enables high-quality lens structures regarding surface roughness and arrangement precision with arbitrary 2D geometry. To provide point foci, crossed pairs of lenses are used. Condenser lenses have been made utilizing deep x-ray lithographic patterning of thick SU-8 layers, too, whereas in this case, the aperture is limited due to process restrictions. Thus, in terms of large apertures, condenser lenses made of structured and rolled polyimide film are more attractive. Both condenser types, x-ray mosaic lenses and rolled x-ray prism lenses (RXPLs), are considered to be implemented into a microscope setup. The x-ray optical elements mentioned above are characterized with synchrotron radiation and x-ray laboratory sources, respectively.

  16. X-Ray Microscopy at BESSY: From Nano-Tomography to Fs-Imaging

    SciTech Connect

    Schneider, G.; Heim, S.; Rehbein, S.; Eichert, D.; Guttmann, P.

    2007-01-19

    The BESSY X-ray microscopy group has developed a new full-field x-ray microscope with glass capillary condenser. It permits tomography and spectromicroscopy of cryogenic as well as heated samples. Correlative light and x-ray microscopy is supported by an incorporated high resolution light microscope. Spectromicroscopy with polarized x-rays from a helical undulator can be performed with E/{delta}E = 104. With the planned BESSY High Gain Harmonic Generation Free Electron Laser (HGHG-FEL) x-ray imaging with ultra-short pulses and an integral photon flux of about 1011 photons/pulse in an energy bandwidth of 0.1% will be possible. Single shot imaging with a full field Transmission X-ray Microscope (TXM) employing a beam shaper as a condenser will be feasible with 20 fs pulses.

  17. X-Ray Microscopy at BESSY: From Nano-Tomography to Fs-Imaging

    NASA Astrophysics Data System (ADS)

    Schneider, G.; Guttmann, P.; Heim, S.; Rehbein, S.; Eichert, D.; Niemann, B.

    2007-01-01

    The BESSY X-ray microscopy group has developed a new full-field x-ray microscope with glass capillary condenser. It permits tomography and spectromicroscopy of cryogenic as well as heated samples. Correlative light and x-ray microscopy is supported by an incorporated high resolution light microscope. Spectromicroscopy with polarized x-rays from a helical undulator can be performed with E/ΔE = 104. With the planned BESSY High Gain Harmonic Generation Free Electron Laser (HGHG-FEL) x-ray imaging with ultra-short pulses and an integral photon flux of about 1011 photons/pulse in an energy bandwidth of 0.1% will be possible. Single shot imaging with a full field Transmission X-ray Microscope (TXM) employing a beam shaper as a condenser will be feasible with 20 fs pulses.

  18. Automatic Peak Identification in Scanning Electron Microscopy/Energy Dispersive X-ray (SEM/EDS) Microanalysis: Can You Always Trust the Results?

    NASA Astrophysics Data System (ADS)

    Newbury, D.

    2006-05-01

    The degree of sophistication of computer-aided scanning electron microscopy/energy dispersive x-ray spectrometry (SEM/EDS) microanalysis has advanced to the point where it is possible with a single command to automatically perform sequential qualitative analysis (peak identification) and quantitative analysis and then create a report of analysis with full statistical support. Often the actual algorithms employed in commercial software for each stage of the analysis are not provided or tested in sufficient detail nor are any inherent limitations in applying such "black box" software described to enable the analyst to estimate the performance. The identification of the elements responsible for the characteristic peaks in the EDS spectrum is obviously the first critical step in performing a robust analysis. Can the software be trusted to always deliver the correct elemental identification for the easiest possible case: peaks with high intensity and high peak-to-background that arise from major constituents (i.e., concentration, C above 0.1 mass fraction = 10 weight percent) and which do not suffer peak interference from another constituent? Unfortunately, testing of automatic peak identification procedures in a series of commercial systems has revealed that serious mistakes occur approximately 3 to 5 percent of the time for this easiest case [1]. Moreover, these mistakes are not random but occur systematically for certain elements. The situation is even worse when minor (C from 0.01 to 0.1) and trace (C less than 0.01) constituents are of interest or when analysis is performed under "low voltage" conditions (beam energy 5 keV or less). The prudent analyst will always use manual peak identification procedures to provide confirmation of automatic peak identification results before proceeding to quantitative analysis [2]. [1] Newbury, D., Microscopy and Microanalysis, 11 (2005) 545. [2] Goldstein, J., Newbury, D., Joy, D., Lyman, C., Echlin, P., Lifshin, E., Sawyer, L

  19. Quantitative study of particle size distribution in an in-situ grown Al–TiB{sub 2} composite by synchrotron X-ray diffraction and electron microscopy

    SciTech Connect

    Tang, Y.; Chen, Z.; Borbély, A.; Ji, G.; Zhong, S.Y.; Schryvers, D.; Ji, V.

    2015-04-15

    Synchrotron X-ray diffraction and transmission electron microscopy (TEM) were applied to quantitatively characterize the average particle size and size distribution of free-standing TiB{sub 2} particles and TiB{sub 2} particles in an in-situ grown Al–TiB{sub 2} composite. The detailed evaluations were carried out by X-ray line profile analysis using the restricted moment method and multiple whole profile fitting procedure (MWP). Both numerical methods indicate that the formed TiB{sub 2} particles are well crystallized and free of crystal defects. The average particle size determined from different Bragg reflections by the restricted moment method ranges between 25 and 55 nm, where the smallest particle size is determined using the 110 reflection suggesting the highest lateral-growth velocity of (110) facets. The MWP method has shown that the in-situ grown TiB{sub 2} particles have a very low dislocation density (~ 10{sup 11} m{sup −} {sup 2}) and their size distribution can be described by a log-normal distribution. Good agreement was found between the results obtained from the restricted moment and MWP methods, which was further confirmed by TEM. - Highlights: • Accurate quantitative characterization of in-situ grown T{sub i}B{sub 2} particles has been achieved. • Particle size anisotropy was revealed indicating 110 facets being largest during T{sub i}B{sub 2} growth. • A wide size distribution was observed for T{sub i}B{sub 2} particles with a dominant size smaller than 100 nm.

  20. X-Ray Diffraction Microscopy of Magnetic Structures

    SciTech Connect

    Turner, J.; Lima, E.; Huang, X.; Krupin, O.; Seu, K.; Parks, D.; Kevan, S.; Kisslinger, K.; McNulty, I.; Gambino, R.; Mangin, S.; Roy, S. and Fischer, P.

    2011-07-14

    We report the first proof-of-principle experiment of iterative phase retrieval from magnetic x-ray diffraction. By using the resonant x-ray excitation process and coherent x-ray scattering, we show that linearly polarized soft x rays can be used to image both the amplitude and the phase of magnetic domain structures. We recovered the magnetic structure of an amorphous terbium-cobalt thin film with a spatial resolution of about 75 nm at the Co L{sub 3} edge at 778 eV. In comparison with soft x-ray microscopy images recorded with Fresnel zone plate optics at better than 25 nm spatial resolution, we find qualitative agreement in the observed magnetic structure.

  1. A hard X-ray nanoprobe beamline for nanoscale microscopy

    PubMed Central

    Winarski, Robert P.; Holt, Martin V.; Rose, Volker; Fuesz, Peter; Carbaugh, Dean; Benson, Christa; Shu, Deming; Kline, David; Stephenson, G. Brian; McNulty, Ian; Maser, Jörg

    2012-01-01

    The Hard X-ray Nanoprobe Beamline (or Nanoprobe Beamline) is an X-ray microscopy facility incorporating diffraction, fluorescence and full-field imaging capabilities designed and operated by the Center for Nanoscale Materials and the Advanced Photon Source at Sector 26 of the Advanced Photon Source at Argonne National Laboratory. This facility was constructed to probe the nanoscale structure of biological, environmental and material sciences samples. The beamline provides intense focused X-rays to the Hard X-ray Nanoprobe (or Nanoprobe) which incorporates Fresnel zone plate optics and a precision laser sensing and control system. The beamline operates over X-ray energies from 3 to 30 keV, enabling studies of most elements in the periodic table, with a particular emphasis on imaging transition metals. PMID:23093770

  2. Deflection gating for time-resolved x-ray magnetic circular dichroism-photoemission electron microscopy using synchrotron radiation

    SciTech Connect

    Wiemann, C.; Kaiser, A. M.; Cramm, S.; Schneider, C. M.

    2012-06-15

    In this paper, we present a newly developed gating technique for a time-resolving photoemission microscope. The technique makes use of an electrostatic deflector within the microscope's electron optical system for fast switching between two electron-optical paths, one of which is used for imaging, while the other is blocked by an aperture stop. The system can be operated with a switching time of 20 ns and shows superior dark current rejection. We report on the application of this new gating technique to exploit the time structure in the injection bunch pattern of the synchrotron radiation source BESSY II at Helmholtz-Zentrum Berlin for time-resolved measurements in the picosecond regime.

  3. Deflection gating for time-resolved x-ray magnetic circular dichroism-photoemission electron microscopy using synchrotron radiation.

    PubMed

    Wiemann, C; Kaiser, A M; Cramm, S; Schneider, C M

    2012-06-01

    In this paper, we present a newly developed gating technique for a time-resolving photoemission microscope. The technique makes use of an electrostatic deflector within the microscope's electron optical system for fast switching between two electron-optical paths, one of which is used for imaging, while the other is blocked by an aperture stop. The system can be operated with a switching time of 20 ns and shows superior dark current rejection. We report on the application of this new gating technique to exploit the time structure in the injection bunch pattern of the synchrotron radiation source BESSY II at Helmholtz-Zentrum Berlin for time-resolved measurements in the picosecond regime. PMID:22755633

  4. Cryogenic X-ray Diffraction Microscopy for Biological Samples

    SciTech Connect

    E Lima; L Wiegart; P Pernot; M Howells; J Timmins; F Zontone; A Madsen

    2011-12-31

    X-ray diffraction microscopy (XDM) is well suited for nondestructive, high-resolution biological imaging, especially for thick samples, with the high penetration power of x rays and without limitations imposed by a lens. We developed nonvacuum, cryogenic (cryo-) XDM with hard x rays at 8 keV and report the first frozen-hydrated imaging by XDM. By preserving samples in amorphous ice, the risk of artifacts associated with dehydration or chemical fixation is avoided, ensuring the imaging condition closest to their natural state. The reconstruction shows internal structures of intact D. radiodurans bacteria in their natural contrast.

  5. Sixth International Conference on X-ray Microscopy

    SciTech Connect

    Robinson, Arthur L.

    1999-08-23

    More than 180 participants from around the world crowded the Clark Kerr Campus of the University of California, Berkeley, from August 1-6, 1999 for the Sixth International Conference on X-Ray Microscopy (XRM99). Held every three years since 1983, the XRM conferences have become the primary international forum for the presentation and discussion of advances in high-spatial-resolution x-ray imaging and applications (including the use of x-ray spectroscopic and analytical techniques) in biological and medical sciences, environmental and soil sciences, and materials and surface sciences.

  6. X-ray and Cryo-electron Microscopy Structures of Monalysin Pore-forming Toxin Reveal Multimerization of the Pro-form*

    PubMed Central

    Leone, Philippe; Bebeacua, Cecilia; Opota, Onya; Kellenberger, Christine; Klaholz, Bruno; Orlov, Igor; Cambillau, Christian; Lemaitre, Bruno; Roussel, Alain

    2015-01-01

    β-Barrel pore-forming toxins (β-PFT), a large family of bacterial toxins, are generally secreted as water-soluble monomers and can form oligomeric pores in membranes following proteolytic cleavage and interaction with cell surface receptors. Monalysin has been recently identified as a β-PFT that contributes to the virulence of Pseudomonas entomophila against Drosophila. It is secreted as a pro-protein that becomes active upon cleavage. Here we report the crystal and cryo-electron microscopy structure of the pro-form of Monalysin as well as the crystal structures of the cleaved form and of an inactive mutant lacking the membrane-spanning region. The overall structure of Monalysin displays an elongated shape, which resembles those of β-pore-forming toxins, such as Aerolysin, but is devoid of a receptor-binding domain. X-ray crystallography, cryo-electron microscopy, and light-scattering studies show that pro-Monalysin forms a stable doughnut-like 18-mer complex composed of two disk-shaped nonamers held together by N-terminal swapping of the pro-peptides. This observation is in contrast with the monomeric pro-form of the other β-PFTs that are receptor-dependent for membrane interaction. The membrane-spanning region of pro-Monalysin is fully buried in the center of the doughnut, suggesting that upon cleavage of pro-peptides, the two disk-shaped nonamers can, and have to, dissociate to leave the transmembrane segments free to deploy and lead to pore formation. In contrast with other toxins, the delivery of 18 subunits at once, nearby the cell surface, may be used to bypass the requirement of receptor-dependent concentration to reach the threshold for oligomerization into the pore-forming complex. PMID:25847242

  7. X-ray fluorescence (conventional and 3D) and scanning electron microscopy for the investigation of Portuguese polychrome glazed ceramics: Advances in the knowledge of the manufacturing techniques

    NASA Astrophysics Data System (ADS)

    Guilherme, A.; Coroado, J.; dos Santos, J. M. F.; Lühl, L.; Wolff, T.; Kanngießer, B.; Carvalho, M. L.

    2011-05-01

    This work shows the first analytical results obtained by X-Ray Fluorescence (XRF) (conventional and 3D) and Scanning Electron Microscopy with Energy Dispersive System (SEM-EDS) on original Portuguese ceramic pieces produced between the 16th and 18th centuries in Coimbra and Lisbon. Experts distinguished these productions based only on the color, texture and brightness, which originates mislabeling in some cases. Thanks to lateral and spatial resolution in the micrometer regime, the results obtained with μ-XRF were essential in determining the glaze and pigment thicknesses by monitoring the profile of the most abundant element in each "layer". Furthermore, the dissemination of these elements throughout the glaze is different depending on the glaze composition, firing temperature and on the pigment itself. Hence, the crucial point of this investigation was to analyze and understand the interfaces color/glaze and glaze/ceramic support. Together with the XRF results, images captured by SEM and the corresponding semi-quantitative EDS data revealed different manufacturing processes used by the two production centers. Different capture modes were suitable to distinguish different crystals from the minerals that confer the color of the pigments used and to enhance the fact that some of them are very well spread through the glassy matrix, sustaining the theory of an evolved and careful procedure in the manufacturing process of the glaze.

  8. Application of Scanning Electron Microscopy/Energy-Dispersive X-Ray Spectroscopy for Characterization of Detrital Minerals in Karst Cave Speleothems.

    PubMed

    Zupančič, Nina; Miler, Miloš; Šebela, Stanka; Jarc, Simona

    2016-02-01

    Micro-scale observations in karst caves help to identify different processes that shaped local morphology. Scanning electron microscopy/energy-dispersive X-ray spectroscopy inspection of speleothems from two karst caves in Slovenia, Predjama and Črna Jama, confirmed the presence of sub-angular to sub-rounded detrital fragments of clay minerals, feldspars, quartz, Fe-oxides/hydroxides, rutile and Nb-rutile, xenotime, kassite, allanite, fluorapatite, epidote, ilmenite, monazite, sphene, and zircon, between 2 and 50 μm across. These occur in porous layers separating calcite laminae in the clayey coating on the layer below the surface of the speleothems, and are also incorporated within actual crystals. It is likely that they are derived from the weathered rocks of the Eocene flysch. Probably they were first transported into the caves by floodwaters forming cave sediments. Later, depending upon the climate conditions, they were moved by air currents or by water to the surface of active speleothems. They might also be redeposited from overlying soils enriched with wind-transported minerals from the flysch, or from higher passages filled with weathered flysch sediment, by drip water percolating through the fissured limestone. As some of the identified minerals are carriers of rare earth elements, Ti and Zr, their presence could affect any palaeoclimatic interpretations that are based upon the geochemical composition of the speleothems. PMID:26914996

  9. Wavefront propagation simulations for a UV/soft x-ray beamline: Electron Spectro-Microscopy beamline at NSLS-II

    NASA Astrophysics Data System (ADS)

    Canestrari, N.; Bisogni, V.; Walter, A.; Zhu, Y.; Dvorak, J.; Vescovo, E.; Chubar, O.

    2014-09-01

    A "source-to-sample" wavefront propagation analysis of the Electron Spectro-Microscopy (ESM) UV / soft X-ray beamline, which is under construction at the National Synchrotron Light Source II (NSLS-II) in the Brookhaven National Laboratory, has been conducted. All elements of the beamline - insertion device, mirrors, variable-line-spacing gratings and slits - are included in the simulations. Radiation intensity distributions at the sample position are displayed for representative photon energies in the UV range (20 - 100 eV) where diffraction effects are strong. The finite acceptance of the refocusing mirrors is the dominating factor limiting the spatial resolution at the sample (by ~3 μm at 20 eV). Absolute estimates of the radiation flux and energy resolution at the sample are also obtained from the electromagnetic calculations. The analysis of the propagated UV range undulator radiation at different deflection parameter values demonstrates that within the beamline angular acceptance a slightly "red-shifted" radiation provides higher flux at the sample and better energy resolution compared to the on-axis resonant radiation of the fundamental harmonic.

  10. A case of hut lung: scanning electron microscopy with energy dispersive x-ray spectroscopy analysis of a domestically acquired form of pneumoconiosis.

    PubMed

    Mukhopadhyay, Sanjay; Gujral, Manmeet; Abraham, Jerrold L; Scalzetti, Ernest M; Iannuzzi, Michael C

    2013-07-01

    Hut lung is a pneumoconiosis caused by exposure to smoke derived from biomass fuels used for cooking in poorly ventilated huts. We report, to our knowledge, the first analysis of the dust deposited in the lungs in hut lung by scanning electron microscopy with energy dispersive x-ray spectroscopy (SEM/EDS). A Bhutanese woman presented with shortness of breath and an abnormal chest radiograph. Chest CT scan showed innumerable tiny bilateral upper lobe centrilobular nodules. Transbronchial biopsy revealed mild interstitial fibrosis with heavy interstitial deposition of black dust. SEM/EDS showed that the dust was carbonaceous, with smaller yet substantial numbers of silica and silicate particles. Additional history revealed use of a wood/coal-fueled stove in a small, poorly ventilated hut for 45 years. The possibility of hut lung should be considered in women from countries where use of biomass-fueled stoves for cooking is common. Our findings support the classification of this condition as a mixed-dust pneumoconiosis. PMID:23880681

  11. Evaluation of LED therapy at 945nm on bone repair by micro x-ray fluorescence spectroscopy and scanning electron microscopy

    NASA Astrophysics Data System (ADS)

    Diamantino, Alexandre G.; Nicolau, Renata A.; de Oliveira, Marco A.; Santo, Ana Maria E.

    2011-07-01

    Phototherapy is able to modulate cellular metabolism of bone tissue and consequently accelerate the repair. The aim of this study was to evaluate the effect of this therapy in repair of bone monocortical defects in femurs of thirty male Wistar rats. The animals were divided into six groups (five animals for group), including three controls and three irradiated groups with different experimental times (14, 21, and 28 days after surgery). LED was used for the irradiation, emitting non-coherent light in the spectral range of 945+/-20 nm and output power of 48 mW, on one point of irradiation for four minutes. Seven treatment sessions were performed with 48 hours between sessions. For analysis on the bone repair, qualitative and quantitative assessments of Ca and P contents were done by micro x-ray fluorescence spectroscopy (μXRF) and the morphological structure was carried out using Scanning Electron Microscopy (SEM). The results showed the efficiency of infrared LED therapy, because the amount of mineral components analyzed by μXRF and the morphological features of cortical and trabecular bones, demonstrated by the SEM images, showed enhanced bone repair in the irradiated groups when compared to their corresponding control groups at all stages.

  12. Scanning Electron Microscopy and X-Ray Microanalysis for Chemical and Morphological Characterisation of the Inorganic Component of Gunshot Residue: Selected Problems

    PubMed Central

    Brożek-Mucha, Zuzanna

    2014-01-01

    Chosen aspects of examinations of inorganic gunshot particles by means of scanning electron microscopy and energy dispersive X-ray spectrometry technique are presented. The research methodology of particles was worked out, which included a precise and repeatable procedure of the automatic detection and identification of particles as well as the representation of the obtained analytical data in the form of the frequencies of occurrence of particles of certain chemical or morphological class within the whole population of particles revealed in a specimen. On this basis, there were established relationships between the chemical and morphological properties of populations of particles and factors, such as the type of ammunition, the distance from the gun muzzle to the target, the type of a substrate the particles sediment on, and the time between shooting and collecting the specimens. Each of these aspects of examinations of particles revealed a great potential of being utilised in casework, while establishing various circumstances of shooting incidents leads to the reconstruction of the course of the studied incident. PMID:25025050

  13. Scanning electron microscopy and X-ray microanalysis for chemical and morphological characterisation of the inorganic component of gunshot residue: selected problems.

    PubMed

    Brożek-Mucha, Zuzanna

    2014-01-01

    Chosen aspects of examinations of inorganic gunshot particles by means of scanning electron microscopy and energy dispersive X-ray spectrometry technique are presented. The research methodology of particles was worked out, which included a precise and repeatable procedure of the automatic detection and identification of particles as well as the representation of the obtained analytical data in the form of the frequencies of occurrence of particles of certain chemical or morphological class within the whole population of particles revealed in a specimen. On this basis, there were established relationships between the chemical and morphological properties of populations of particles and factors, such as the type of ammunition, the distance from the gun muzzle to the target, the type of a substrate the particles sediment on, and the time between shooting and collecting the specimens. Each of these aspects of examinations of particles revealed a great potential of being utilised in casework, while establishing various circumstances of shooting incidents leads to the reconstruction of the course of the studied incident. PMID:25025050

  14. Chemical and morphological study of gunshot residue persisting on the shooter by means of scanning electron microscopy and energy dispersive X-ray spectrometry.

    PubMed

    Brożek-Mucha, Zuzanna

    2011-12-01

    Persistence of gunshot residue (GSR) simultaneously collected from hands, face and hair, and clothing of the shooting person was examined. Samples were collected from five shooters in nine time intervals after a single shoot with a Luger 9 mm pistol, in the range of 0-4 h and examined with scanning electron microscopy and energy dispersive X-ray spectrometry. Numbers of particles, frequencies of occurrence of certain compositions of particles, and their sizes in function of the time intervals were inspected. The greatest numbers of particles were observed in samples collected from hands right after shooting, but they decrease quickly with time. In samples collected from the face smaller initial numbers of particles were found, but they lasted at a similar level longer. The estimated half-life times of particles were less than 1 h for samples taken from the hands, over 1 h for clothing and about 2-3 h for the face. In samples collected at longer intervals after shooting, there were particles present of small sizes and irregular shapes. The results demonstrate that including evidence collected from the suspect's face and hair may increase the probability of detection of GSR in cases when the suspect has not been apprehended immediately after the investigated incident. PMID:22051052

  15. A Study of the Oxidation Behaviour of Pile Grade A (PGA) Nuclear Graphite Using Thermogravimetric Analysis (TGA), Scanning Electron Microscopy (SEM) and X-Ray Tomography (XRT).

    PubMed

    Payne, Liam; Heard, Peter J; Scott, Thomas B

    2015-01-01

    Pile grade A (PGA) graphite was used as a material for moderating and reflecting neutrons in the UK's first generation Magnox nuclear power reactors. As all but one of these reactors are now shut down there is a need to understand the residual state of the material prior to decommissioning of the cores, in particular the location and concentration of key radio-contaminants such as 14C. The oxidation behaviour of unirradiated PGA graphite was studied, in the temperature range 600-1050°C, in air and nitrogen using thermogravimetric analysis, scanning electron microscopy and X-ray tomography to investigate the possibility of using thermal degradation techniques to examine 14C distribution within irradiated material. The thermal decomposition of PGA graphite was observed to follow the three oxidation regimes historically identified by previous workers with limited, uniform oxidation at temperatures below 600°C and substantial, external oxidation at higher temperatures. This work demonstrates that the different oxidation regimes of PGA graphite could be developed into a methodology to characterise the distribution and concentration of 14C in irradiated graphite by thermal treatment. PMID:26575374

  16. Structure refinement of the δ1p phase in the Fe–Zn system by single-crystal X-ray diffraction combined with scanning transmission electron microscopy

    PubMed Central

    Okamoto, Norihiko L.; Tanaka, Katsushi; Yasuhara, Akira; Inui, Haruyuki

    2014-01-01

    The structure of the δ1p phase in the iron−zinc system has been refined by single-crystal synchrotron X-ray diffraction combined with scanning transmission electron microscopy. The large hexagonal unit cell of the δ1p phase with the space group of P63/mmc comprises more or less regular (normal) Zn12 icosahedra, disordered Zn12 icosahedra, Zn16 icosioctahedra and dangling Zn atoms that do not constitute any polyhedra. The unit cell contains 52 Fe and 504 Zn atoms so that the compound is expressed with the chemical formula of Fe13Zn126. All Fe atoms exclusively occupy the centre of normal and disordered icosahedra. Iron-centred normal icosahedra are linked to one another by face- and vertex-sharing forming two types of basal slabs, which are bridged with each other by face-sharing with icosioctahedra, whereas disordered icosahedra with positional disorder at their vertex sites are isolated from other polyhedra. The bonding features in the δ1p phase are discussed in comparison with those in the Γ and ζ phases in the iron−zinc system. PMID:24675597

  17. Investigation of defect clusters in ion-irradiated Ni and NiCo using diffuse X-ray scattering and electron microscopy

    DOE PAGESBeta

    Olsen, Raina J.; Jin, Ke; Lu, Chenyang; Beland, Laurent K.; Wang, Lumin M.; Bei, Hongbin; Specht, Eliot D.; Larson, Bennett C.

    2016-01-01

    The nature of defect clusters in Ni and Nimore » $$_{50}$$Co$$_{50}$$ (NiCo) irradiated at room temperature with 2–16 MeV Ni ions is studied using asymptotic diffuse X-ray scattering and transmission electron microscopy (TEM). Analysis of the scattering data provides separate size distributions for vacancy and interstitial type defect clusters, showing that both types of defect clusters have a smaller size and higher density in NiCo than in Ni. Diffuse scattering results show good quantitative agreement with TEM results for cluster sizes greater than 4 nm diameter, but find that the majority of vacancy clusters are under 2 nm in NiCo, which, if not detected, would lead to the conclusion that defect density was actually lower in the alloy. Interstitial dislocation loops and stacking fault tetrahedra are identified by TEM. Lastly comparison of diffuse scattering lineshapes to those calculated for dislocation loops and SFTs indicates that most of the vacancy clusters are SFTs.« less

  18. Surface characterization of 7S and 11S globulin powders from soy protein examined by X-ray photoelectron spectroscopy and scanning electron microscopy.

    PubMed

    Zhao, Xiaoyan; Chen, Jun; Zhu, Qingjun; Du, Fangling; Ao, Qiang; Liu, Jie

    2011-09-01

    In this study the surface composition of 7S and 11S globulin powders from soybean proteins by aqueous buffer and reverse micelle extractions had been examined using X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Analysis by XPS revealed that the O and N atomic percentage of 7S and 11S globulin surfaces from bis(2-ethylhexyl) sodium sulfosuccinate (AOT) reverse micelle was higher than from aqueous buffer, but the C atomic percentage was lower. The O/C ratio of the 7S globulin powder from aqueous buffer and reverse micelle was similar while significant differences were obtained in the O/C ratio of the 11S globulin powder, N/C atom ratios of the 7S and 11S globulin powders and high-resolution XPS C 1s, N 1s, O 1s spectra. Powder microstructure after reverse micelle treatment showed the presence of small pores, indicating the effect of reverse micelle on the 7S and 11S globulin structure. The obtained results indicated that the reverse micelle could affect the C, O and N components on the surface of soybean proteins. PMID:21555209

  19. Morphological and chemical changes in dentin after using endodontic agents: Fourier transform Raman spectroscopy, energy-dispersive x-ray fluorescence spectrometry, and scanning electron microscopy study

    NASA Astrophysics Data System (ADS)

    Pascon, Fernanda Miori; Kantovitz, Kamila Rosamilia; Soares, Luís Eduardo Silva; Santo, Ana Maria do Espírito; Martin, Airton Abraha~o.; Puppin-Rontani, Regina Maria

    2012-07-01

    We examine the morphological and chemical changes in the pulp chamber dentin after using endodontic agents by scanning electron microscopy (SEM), Fourier transform Raman spectroscopy (FT-Raman), and micro energy-dispersive x-ray fluorescence spectrometry (μEDXRF). Thirty teeth were sectioned exposing the pulp chamber and divided by six groups (n=5): NT-no treatment; CHX-2% chlorhexidine; CHXE-2% chlorhexidine+17% EDTA E-17% EDTA; SH5-5.25% NaOCl; SH5E-5.25% NaOCl+17% EDTA. The inorganic and organic content was analyzed by FT-Raman. μEDXRF examined calcium (Ca) and phosphorus (P) content as well as Ca/P ratio. Impressions of specimens were evaluated by SEM. Data were submitted to Kruskal-Wallis and Dunn tests (p<0.05). Differences were observed among groups for the 960 cm-1 peak. Ca and P content differences were significant (SH5>NT=SH5E>CHX>E>CHXE). CHXE and E presented the highest Ca/P ratio values compared to the other groups (p<0.05). The SEM images in the EDTA-treated groups had the highest number of open tubules. Erosion in the tubules was observed in CHX and SH5E groups. Endodontic agents change the inorganic and organic content of pulp chamber dentin. NaOCl used alone, or in association with EDTA, was the most effective agent considering chemical and morphological approaches.

  20. Scanning Electron Microscopy and Energy Dispersive X-ray Spectroscopy Studies on Processed Tooth Graft Material by Vacuum-ultrasonic Acceleration

    PubMed Central

    Lee, Eun-Young; Kim, Eun-Suk; Kim, Kyung-Won

    2014-01-01

    Purpose: The current gold standard for clinical jawbone formation involves autogenous bone as a graft material. In addition, demineralized dentin can be an effective graft material. Although demineralized dentin readily induces heterotopic bone formation, conventional decalcification takes three to five days, so, immediate bone grafting after extraction is impossible. This study evaluated the effect of vacuum ultrasonic power on the demineralization and processing of autogenous tooth material and documented the clinical results of rapidly processed autogenous demineralized dentin (ADD) in an alveolar defects patient. Methods: The method involves the demineralization of extracted teeth with detached soft tissues and pulp in 0.6 N HCl for 90 minutes using a heat controlled vacuum-ultrasonic accelerator. The characteristics of processed teeth were evaluated by scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS). Bone grafting using ADD was performed for narrow ridges augmentation in the mandibular area. Results: The new processing method was completed within two hours regardless of form (powder or block). EDS and SEM uniformly demineralized autotooth biomaterial. After six months, bone remodeling was observed in augmented sites and histological examination showed that ADD particles were well united with new bone. No unusual complications were encountered. Conclusion: This study demonstrates the possibility of preparing autogenous tooth graft materials within two hours, allowing immediate one-day grafting after extraction. PMID:27489819

  1. A Study of the Oxidation Behaviour of Pile Grade A (PGA) Nuclear Graphite Using Thermogravimetric Analysis (TGA), Scanning Electron Microscopy (SEM) and X-Ray Tomography (XRT)

    PubMed Central

    Payne, Liam; Heard, Peter J.; Scott, Thomas B.

    2015-01-01

    Pile grade A (PGA) graphite was used as a material for moderating and reflecting neutrons in the UK’s first generation Magnox nuclear power reactors. As all but one of these reactors are now shut down there is a need to understand the residual state of the material prior to decommissioning of the cores, in particular the location and concentration of key radio-contaminants such as 14C. The oxidation behaviour of unirradiated PGA graphite was studied, in the temperature range 600–1050°C, in air and nitrogen using thermogravimetric analysis, scanning electron microscopy and X-ray tomography to investigate the possibility of using thermal degradation techniques to examine 14C distribution within irradiated material. The thermal decomposition of PGA graphite was observed to follow the three oxidation regimes historically identified by previous workers with limited, uniform oxidation at temperatures below 600°C and substantial, external oxidation at higher temperatures. This work demonstrates that the different oxidation regimes of PGA graphite could be developed into a methodology to characterise the distribution and concentration of 14C in irradiated graphite by thermal treatment. PMID:26575374

  2. Investigation of defect clusters in ion-irradiated Ni and NiCo using diffuse X-ray scattering and electron microscopy

    SciTech Connect

    Olsen, Raina J.; Jin, Ke; Lu, Chenyang; Beland, Laurent K.; Wang, Lumin M.; Bei, Hongbin; Specht, Eliot D.; Larson, Bennett C.

    2016-01-01

    The nature of defect clusters in Ni and Ni$_{50}$Co$_{50}$ (NiCo) irradiated at room temperature with 2–16 MeV Ni ions is studied using asymptotic diffuse X-ray scattering and transmission electron microscopy (TEM). Analysis of the scattering data provides separate size distributions for vacancy and interstitial type defect clusters, showing that both types of defect clusters have a smaller size and higher density in NiCo than in Ni. Diffuse scattering results show good quantitative agreement with TEM results for cluster sizes greater than 4 nm diameter, but find that the majority of vacancy clusters are under 2 nm in NiCo, which, if not detected, would lead to the conclusion that defect density was actually lower in the alloy. Interstitial dislocation loops and stacking fault tetrahedra are identified by TEM. Lastly comparison of diffuse scattering lineshapes to those calculated for dislocation loops and SFTs indicates that most of the vacancy clusters are SFTs.

  3. X-ray Free-electron Lasers

    SciTech Connect

    Feldhaus, J.; Arthur, J.; Hastings, J.B.; /SLAC

    2007-02-23

    In a free-electron laser (FEL) the lasing medium is a high-energy beam of electrons flying with relativistic speed through a periodic magnetic field. The interaction between the synchrotron radiation that is produced and the electrons in the beam induces a periodic bunching of the electrons, greatly increasing the intensity of radiation produced at a particular wavelength. Depending only on a phase match between the electron energy and the magnetic period, the wavelength of the FEL radiation can be continuously tuned within a wide spectral range. The FEL concept can be adapted to produce radiation wavelengths from millimeters to Angstroms, and can in principle produce hard x-ray beams with unprecedented peak brightness, exceeding that of the brightest synchrotron source by ten orders of magnitude or more. This paper focuses on short-wavelength FELs. It reviews the physics and characteristic properties of single-pass FELs, as well as current technical developments aiming for fully coherent x-ray radiation pulses with pulse durations in the 100 fs to 100 as range. First experimental results at wavelengths around 100 nm and examples of scientific applications planned on the new, emerging x-ray FEL facilities are presented.

  4. Crystallization, preliminary X-ray crystallographic and cryo-electron microscopy analysis of a bifunctional enzyme fucokinase/l-fucose-1-P-guanylyltransferase from Bacteroides fragilis

    PubMed Central

    Cheng, Chongyun; Gu, Jianhua; Su, Jing; Ding, Wei; Yin, Jie; Liang, Wenguang; Yu, Xiaoxia; Ma, Jun; Wang, Peng George; Xiao, Zhicheng; Liu, Zhi-Jie

    2014-01-01

    Fucokinase/l-fucose-1-P-guanylyltransferase (FKP) is a bifunctional enzyme which converts l-fucose to Fuc-1-P and thence to GDP-l-fucose through a salvage pathway. The molecular weights of full-length FKP (F-FKP) and C-terminally truncated FKP (C-FKP, residues 300–949) are 105.7 and 71.7 kDa, respectively. In this study, both recombinant F-FKP and C-FKP were expressed and purified. Size-exclusion chromatography experiments and analytical ultracentrifugation results showed that both F-FKP and C-FKP are trimers. Native F-FKP protein was crystallized by the vapour-diffusion method and the crystals belonged to space group P212121 and diffracted synchrotron X-rays to 3.7 Å resolution. The crystal unit-cell parameters are a = 91.36, b = 172.03, c = 358.86 Å, α = β = γ = 90.00°. The three-dimensional features of the F-FKP molecule were observed by cryo-EM (cryo-electron microscopy). The preliminary cryo-EM experiments showed the F-FKP molecules as two parallel disc-shaped objects stacking together. Combining all results together, it is assumed that there are six FKP molecules in one asymmetric unit, which corresponds to a calculated Matthews coefficient of 2.19 Å3 Da−1 with 43.83% solvent content. These preliminary crystallographic and cryo-EM microscopy analyses provide basic structural information on FKP. PMID:25195892

  5. Nanoscale Imaging of Buried Structures with Elemental Specificity Using Resonant X-Ray Diffraction Microscopy

    SciTech Connect

    Song, Changyong; Bergstrom, Raymond; Ramunno-Johnson, Damien; Jiang, Huaidong; Miao, Jianwei; Paterson, David; Jonge, Martin D. de; McNulty, Ian; Lee, Jooyoung; Wang, Kang L.

    2008-01-18

    We report the first demonstration of resonant x-ray diffraction microscopy for element specific imaging of buried structures with a pixel resolution of {approx}15 nm by exploiting the abrupt change in the scattering cross section near electronic resonances. We performed nondestructive and quantitative imaging of buried Bi structures inside a Si crystal by directly phasing coherent x-ray diffraction patterns acquired below and above the Bi M{sub 5} edge. We anticipate that resonant x-ray diffraction microscopy will be applied to element and chemical state specific imaging of a broad range of systems including magnetic materials, semiconductors, organic materials, biominerals, and biological specimens.

  6. Femtosecond laser-electron x-ray source

    DOEpatents

    Hartemann, Frederic V.; Baldis, Hector A.; Barty, Chris P.; Gibson, David J.; Rupp, Bernhard

    2004-04-20

    A femtosecond laser-electron X-ray source. A high-brightness relativistic electron injector produces an electron beam pulse train. A system accelerates the electron beam pulse train. The femtosecond laser-electron X-ray source includes a high intra-cavity power, mode-locked laser and an x-ray optics system.

  7. The effect of phytostabilization on Zn speciation in a dredged contaminated sediment using scanning electron microscopy, X-ray fluorescence, EXAFS spectroscopy, and principal components analysis

    NASA Astrophysics Data System (ADS)

    Panfili, Frédéric; Manceau, Alain; Sarret, Géraldine; Spadini, Lorenzo; Kirpichtchikova, Tatiana; Bert, Valérie; Laboudigue, Agnès; Marcus, Matthew A.; Ahamdach, Noureddine; Libert, Marie-Françoise

    2005-05-01

    The maintenance of waterways generates large amounts of dredged sediments, which are deposited on adjacent land surfaces. These sediments are often rich in metal contaminants and present a risk to the local environment. Understanding how the metals are immobilized at the molecular level is critical for formulating effective metal containment strategies such as phytoremediation. In the present work, the mineralogical transformations of Zn-containing phases induced by two graminaceous plants (A grostis tenuis and Festuca rubra) in a contaminated sediment ([Zn] = 4700 mg kg -1, [P 2O 5] = 7000 mg kg -1, pH = 7.8), untreated or amended with hydroxylapatite (AP) or Thomas basic slag (TS), were investigated after two yr of pot experiment by scanning electron microscopy coupled with energy-dispersive spectrometry (SEM-EDS), synchrotron-based X-ray microfluorescence (μ-SXRF), and powder and laterally resolved extended X-ray absorption fine structure (μ-EXAFS) spectroscopy. The number and nature of Zn species were evaluated by principal component (PCA) and least-squares fitting (LSF) analysis of the entire set of μ-EXAFS spectra, which included up to 32 individual spectra from regions of interest varying in chemical composition. Seven Zn species were identified at the micrometer scale: sphalerite, gahnite, franklinite, Zn-containing ferrihydrite and phosphate, (Zn-Al)-hydrotalcite, and Zn-substituted kerolite-like trioctahedral phyllosilicate. Bulk fractions of each species were quantified by LSF of the powder EXAFS spectra to linear combinations of the identified Zn species spectra. In the untreated and unvegetated sediment, Zn was distributed as ˜50% (mole ratio of total Zn) sphalerite, ˜40% Zn-ferrihydrite, and ˜10 to 20% (Zn-Al)-hydrotalcite plus Zn-phyllosilicate. In unvegetated but amended sediments (AP and TS), ZnS and Zn-ferrihydrite each decreased by 10 to 20% and were replaced by Zn-phosphate (˜30˜40%). In the presence of plants, ZnS was almost completely

  8. Magnetic anisotropy, scanning electron microscopy, and X ray pole figure goniometry study of inclination shallowing in a compacting clay-rich sediment

    NASA Astrophysics Data System (ADS)

    Kodama, K. P.

    1992-12-01

    Anisotropy of anhysteretic remanence (AAR), scanning electron microscopy (SEM), and X ray pole figure goniometry studies of clay-rich sediments were conducted to delineate the interactions between magnetite and clay particles which cause inclination shallowing during compaction. These studies used synthetic sediments composed of kaolinite or illite and two grain sizes of mgnetite, 0.45 μm and 2-3 μm. Natural marine sediments which contained 40-50% clay were also used. The sediments were compacted by pressures as high as 0.157 MPa. The sediments' porosity decrease suggests that the compaction experiments model burial depths up to 400-500 m. The main result of this study is that inclination shallowing and void ratio versus pressure curves show two points where behavior changes. A rapid decrease in inclination and void ratio occurs up to a pressure of 0.02 MPa. This is accompanied by a magnetic intensity decrease of 20-30%. Compaction at pressures between 0.02 MPa and 0.05 MPa causes a further decrease in these parameters at moderate rates, while compaction at pressures above 0.05 MPa causes very little change. Percent magnetic anisotropy and X ray pole figure intensity ratio versus pressure curves show only one point where behavior changes at 0.05 MPa with a rapid increase at lower pressures and little change at higher pressures. A model to explain this behavior, based on the SEM obsevations as well as the magnetic anisotropy, pole figure, and inclination data, suggests that compaction up to 0.02 MPa causes a decrease in pore volume with little reorientation of clay particles. Some magnetic particles are firmly attached to clay particles, whereas other loosely attached particles are either randomized or subvertical ones are preferentially disturbed causing inclination shallowing and an intensity decrease. At pressures between 0.02 MPa and 0.05 MPa, magnetite particles have become firmly attached to clay particles and start to follow the reorientation of clay

  9. High-resolution x-ray diffraction microscopy of specifically labeled yeast cells

    DOE PAGESBeta

    Nelson, Johanna; Huang, Xiaojing; Steinbrener, Jan; Shapiro, David; Kirz, Janos; Marchesini, Stephano; Neiman, Aaron M.; Turner, Joshua J.; Jacobsen, Chris

    2010-04-20

    X-ray diffraction microscopy complements other x-ray microscopy methods by being free of lens-imposed radiation dose and resolution limits, and it allows for high-resolution imaging of biological specimens too thick to be viewed by electron microscopy. We report here the highest resolution (11-13 nm) x-ray diffraction micrograph of biological specimens, and a demonstration of molecular-specific gold labeling at different depths within cells via through-focus propagation of the reconstructed wavefield. The lectin concanavalin A conjugated to colloidal gold particles was used to label the α-mannan sugar in the cell wall of the yeast Saccharomyces cerevisiae. Cells were plunge-frozen in liquid ethane andmore » freeze-dried, after which they were imaged whole using x-ray diffraction microscopy at 750 eV photon energy.« less

  10. High-resolution x-ray diffraction microscopy of specifically labeled yeast cells

    SciTech Connect

    Nelson, Johanna; Huang, Xiaojing; Steinbrener, Jan; Shapiro, David; Kirz, Janos; Marchesini, Stephano; Neiman, Aaron M.; Turner, Joshua J.; Jacobsen, Chris

    2010-04-20

    X-ray diffraction microscopy complements other x-ray microscopy methods by being free of lens-imposed radiation dose and resolution limits, and it allows for high-resolution imaging of biological specimens too thick to be viewed by electron microscopy. We report here the highest resolution (11-13 nm) x-ray diffraction micrograph of biological specimens, and a demonstration of molecular-specific gold labeling at different depths within cells via through-focus propagation of the reconstructed wavefield. The lectin concanavalin A conjugated to colloidal gold particles was used to label the α-mannan sugar in the cell wall of the yeast Saccharomyces cerevisiae. Cells were plunge-frozen in liquid ethane and freeze-dried, after which they were imaged whole using x-ray diffraction microscopy at 750 eV photon energy.

  11. Contact microscopy with a soft x-ray laser

    SciTech Connect

    DiCicco, D.S.; Kim, D.; Rosser, R.J.; Skinner, C.H.; Suckewer, S.; Gupta, A.P.; Hirschberg, J.G.

    1989-03-01

    A soft x-ray laser of output energy 1-3 mJ at 19.2 nm has been used to record high resolution images of biological specimens. The contact images were recorded on photoresist which was later viewed in a scanning electron microscope. We also present a Composite Optical X- ray Laser Microscope ''COXRALM'' of novel design. 14 refs., 8 figs., 1 tab.

  12. X-ray dense cellular inclusions in the cells of the green alga Chlamydomonas reinhardtii as seen by soft-x-ray microscopy

    SciTech Connect

    Stead, A.D.; Ford, T.W.; Page, A.M.; Brown, J.T.; Meyer-Ilse, W.

    1997-04-01

    Soft x-rays, having a greater ability to penetrate biological material than electrons, have the potential for producing images of intact, living cells. In addition, by using the so-called {open_quotes}water window{close_quotes} area of the soft x-ray spectrum, a degree of natural contrast is introduced into the image due to differential absorption of the wavelengths by compounds with a high carbon content compared to those with a greater oxygen content. The variation in carbon concentration throughout a cell therefore generates an image which is dependent upon the carbon density within the specimen. Using soft x-ray contact microscopy the authors have previously examined the green alga Chlamydomonas reinhardtii, and the most prominent feature of the cells are the numerous x-ray absorbing spheres, But they were not seen by conventional transmission electron microscopy. Similar structures have also been reported by the Goettingen group using their cryo transmission x-ray microscope at BESSY. Despite the fact that these spheres appear to occupy up to 20% or more of the cell volume when seen by x-ray microscopy, they are not visible by transmission electron microscopy. Given the difficulties and criticisms associated with soft x-ray contact microscopy, the present study was aimed at confirming the existence of these cellular inclusions and learning more of their possible chemical composition.

  13. Laser-based X-ray and electron source for X-ray fluorescence studies

    NASA Astrophysics Data System (ADS)

    Valle Brozas, F.; Crego, A.; Roso, L.; Peralta Conde, A.

    2016-08-01

    In this work, we present a modification to conventional X-rays fluorescence using electrons as excitation source and compare it with the traditional X-ray excitation for the study of pigments. For this purpose, we have constructed a laser-based source capable to produce X-rays as well as electrons. Because of the large penetration depth of X-rays, the collected fluorescence signal is a combination of several material layers of the artwork under study. However, electrons are stopped in the first layers, allowing a more superficial analysis. We show that the combination of both excitation sources can provide extremely valuable information about the structure of the artwork.

  14. High spatial resolution soft-x-ray microscopy

    SciTech Connect

    Meyer-Ilse, W.; Medecki, H.; Brown, J.T.

    1997-04-01

    A new soft x-ray microscope (XM-1) with high spatial resolution has been constructed by the Center for X-ray Optics. It uses bending magnet radiation from beamline 6.1 at the Advanced Light Source, and is used in a variety of projects and applications in the life and physical sciences. Most of these projects are ongoing. The instrument uses zone plate lenses and achieves a resolution of 43 nm, measured over 10% to 90% intensity with a knife edge test sample. X-ray microscopy permits the imaging of relatively thick samples, up to 10 {mu}m thick, in water. XM-1 has an easy to use interface, that utilizes visible light microscopy to precisely position and focus the specimen. The authors describe applications of this device in the biological sciences, as well as in studying industrial applications including structured polymer samples.

  15. Biological imaging by soft x-ray diffraction microscopy

    DOE PAGESBeta

    Shapiro, D.; Thibault, P.; Beetz, T.; Elser, V.; Howells, M.; Jacobsen, C.; Kirz, J.; Lima, E.; Miao, H.; Neiman, A. M.; et al

    2005-10-25

    We have used the method of x-ray diffraction microscopy to image the complex-valued exit wave of an intact and unstained yeast cell. The images of the freeze-dried cell, obtained by using 750-eV x-rays from different angular orientations, portray several of the cell's major internal components to 30-nm resolution. The good agreement among the independently recovered structures demonstrates the accuracy of the imaging technique. To obtain the best possible reconstructions, we have implemented procedures for handling noisy and incomplete diffraction data, and we propose a method for determining the reconstructed resolution. This work represents a previously uncharacterized application of x-ray diffractionmore » microscopy to a specimen of this complexity and provides confidence in the feasibility of the ultimate goal of imaging biological specimens at 10-nm resolution in three dimensions.« less

  16. Biological imaging by soft x-ray diffraction microscopy

    SciTech Connect

    Shapiro, D.; Thibault, P.; Beetz, T.; Elser, V.; Howells, M.; Jacobsen, C.; Kirz, J.; Lima, E.; Miao, H.; Neiman, A. M.; Sayre, D.

    2005-10-25

    We have used the method of x-ray diffraction microscopy to image the complex-valued exit wave of an intact and unstained yeast cell. The images of the freeze-dried cell, obtained by using 750-eV x-rays from different angular orientations, portray several of the cell's major internal components to 30-nm resolution. The good agreement among the independently recovered structures demonstrates the accuracy of the imaging technique. To obtain the best possible reconstructions, we have implemented procedures for handling noisy and incomplete diffraction data, and we propose a method for determining the reconstructed resolution. This work represents a previously uncharacterized application of x-ray diffraction microscopy to a specimen of this complexity and provides confidence in the feasibility of the ultimate goal of imaging biological specimens at 10-nm resolution in three dimensions.

  17. Nearly Uniform Decaosmium Clusters Supported on MgO: Characterization by X-ray Absorption Spectroscopy and Scanning Transmission Electron Microscopy

    SciTech Connect

    Kulkarni, A.; Mehraeen, S; Reed, B; Okamoto, N; Browning, N; Gates, B

    2009-01-01

    Samples containing small, nearly uniform clusters of a heavy metal, Os, were prepared on a high-area porous support consisting of light atoms, MgO, to provide an opportunity for a critical assessment of estimates of cluster size determined by extended X-ray absorption fine structure (EXAFS) spectroscopy and high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM). Supported carbonyl clusters approximated as decaosmium were prepared by reductive carbonylation of adsorbed Os3(CO)12 at 548 K and 1 bar. Infrared (IR) spectra of the clusters resemble those attributed in earlier work to supported clusters similar to [Os10C(CO)24]2-, consistent with the EXAFS data. The spectra indicate a molar yield of decaosmium carbonyl clusters of about 65-70%. As these clusters were treated in flowing H2, they were partially decarbonylated, as shown by IR and EXAFS spectra. The rms (root-mean-square) radii of the undecarbonylated and partially decarbonylated clusters were found by HAADF-STEM to be 3.11 {+-} 0.09 and 3.06 {+-} 0.05 A, respectively, and the close agreement between these values is consistent with the inference that the cluster frame was essentially the same in each. The average rms radius of the undecarbonylated clusters, estimated on the basis of EXAFS data, was 2.94 {+-} 0.07 A, calculated on the basis of the assumption that the osmium frame matched that of [Os10C(CO)24]2-. EXAFS analysis of the data characterizing the partially decarbonylated sample, aided by the STEM results, showed, consistent with the STEM results, that the partial decarbonylation did not lead to a significant change in the rms radius of the metal frame.

  18. Weathering properties of treated southern yellow pine wood examined by X-ray photoelectron spectroscopy, scanning electron microscopy and physical characterization

    NASA Astrophysics Data System (ADS)

    Salaita, Ghaleb N.; Ma, Frank M. S.; Parker, Trudy C.; Hoflund, Gar B.

    2008-04-01

    In this study the weathering behavior of southern yellow pine (SYP) wood samples pretreated in different solutions has been examined using X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and various types of physical characterization regarding material loss and discoloration. The treatment solutions include water as a control, a commercially available water repellent (WR) wood treating additive and polyethylene glycol (PEG) products including PEG PLUS™, PEG 8000 solutions and Compound 20M in varying concentrations. All contained the wood preservative chromated copper arsenate (CCA). One sample was treated with a CCA solution only. The treatments were carried out at 20 °C and 150 psig for 1/2 h after exposure to vacuum (28 mmHg) for 15 min. Simulated weathering was achieved in an Atlas 65-W Weather-Ometer for 2000 h with both light and dark periods and rain. The temperature ranged from 23 °C during the dark cycle to 35 °C during the light cycle. With weathering the XPS O/C ratios increase due to oxidation of the surface. Exposure to UV light results in bond breakage and reaction with oxygen in the presence of air to form organic functional groups such as ?, ?, C dbnd O and/or O-C-O. These oxidized products can protect the underlying wood from deterioration if they are insoluble in water and remain on the surface as a protective coating. If soluble, rain washes the compounds away and assists in the degradation. Correlated changes are observed in the XPS O/C ratios, the high-resolution XPS C 1s spectra, the SEM micrographs and physical measurements including thickness alteration, weight loss, and discoloration by yellowing or whitening of the weathered wood. The PEG treatments are effective in protecting wood with the 2% PEG PLUS treatment providing the best weathering behavior similar to that of the CCA treatment. The WR and water treatments yield the poorest weathering properties.

  19. Orthogonal identification of gunshot residue with complementary detection principles of voltammetry, scanning electron microscopy, and energy-dispersive X-ray spectroscopy: sample, screen, and confirm.

    PubMed

    O'Mahony, Aoife M; Samek, Izabela A; Sattayasamitsathit, Sirilak; Wang, Joseph

    2014-08-19

    Field-deployable voltammetric screening coupled with complementary laboratory-based analysis to confirm the presence of gunshot residue (GSR) from the hands of a subject who has handled, loaded, or discharged a firearm is described. This protocol implements the orthogonal identification of the presence of GSR utilizing square-wave stripping voltammetry (SWSV) as a rapid screening tool along with scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) to confirm the presence of the characteristic morphology and metal composition of GSR particles. This is achieved through the judicious modification of the working electrode of a carbon screen-printed electrode (CSPE) with carbon tape (used in SEM analysis) to fix and retain a sample. A comparison between a subject who has handled and loaded a firearm and a subject who has had no contact with GSR shows the significant variations in voltammetric signals and the presence or absence of GSR-consistent particles and constituent metals. This initial electrochemical screening has no effect on the integrity of the metallic particles, and SEM/EDX analysis conducted prior to and postvoltammetry show no differences in analytical output. The carbon tape is instrumental in retaining the GSR sample after electrochemical analysis, supported by comparison with orthogonal detection at a bare CSPE. This protocol shows great promise as a two-tier detection system for the presence of GSR from the hands of a subject, whereby initial screening can be conducted rapidly onsite by minimally trained operators; confirmation can follow at the same substrate to substantiate the voltammetric results. PMID:25084547

  20. Transmission X-ray microscopy of spider dragline silk.

    PubMed

    Glisović, Anja; Thieme, Jürgen; Guttmann, Peter; Salditt, Tim

    2007-01-30

    We have investigated the structure of spider silk fibers from two different Nephila species and three different Araneus species by transmission X-ray microscopy (TXM). Single fibers and double fibers have been imaged. All images are in agreement with a homogenous density on length scales between the fiber diameter and the resolution of the instrument, which is about 25 nm. PMID:16889826

  1. Applications of Hard X-ray Full-Field Transmission X-ray Microscopy at SSRL

    SciTech Connect

    Liu, Y.; Andrews, J. C.; Mehta, A.; Pianetta, P.; Meirer, F.; Gil, S. Carrasco; Sciau, P.; Mester, Z.

    2011-09-09

    State-of-the-art hard x-ray full-field transmission x-ray microscopy (TXM) at beamline 6-2C of Stanford Synchrotron Radiation Lightsource has been applied to various research fields including biological, environmental, and material studies. With the capability of imaging a 32-micron field-of-view at 30-nm resolution using both absorption mode and Zernike phase contrast, the 3D morphology of yeast cells grown in gold-rich media was investigated. Quantitative evaluation of the absorption coefficient was performed for mercury nanoparticles in alfalfa roots exposed to mercury. Combining XANES and TXM, we also performed XANES-imaging on an ancient pottery sample from the Roman pottery workshop at LaGraufesenque (Aveyron).

  2. Applications of Hard X-ray Full-Field Transmission X-ray Microscopy at SSRL

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Andrews, J. C.; Meirer, F.; Mehta, A.; Gil, S. Carrasco; Sciau, P.; Mester, Z.; Pianetta, P.

    2011-09-01

    State-of-the-art hard x-ray full-field transmission x-ray microscopy (TXM) at beamline 6-2C of Stanford Synchrotron Radiation Lightsource has been applied to various research fields including biological, environmental, and material studies. With the capability of imaging a 32-micron field-of-view at 30-nm resolution using both absorption mode and Zernike phase contrast, the 3D morphology of yeast cells grown in gold-rich media was investigated. Quantitative evaluation of the absorption coefficient was performed for mercury nanoparticles in alfalfa roots exposed to mercury. Combining XANES and TXM, we also performed XANES-imaging on an ancient pottery sample from the Roman pottery workshop at LaGraufesenque (Aveyron).

  3. Soft X-ray contact microscopy of nematode Caenorhabditis elegans

    NASA Astrophysics Data System (ADS)

    Poletti, G.; Orsini, F.; Batani, D.; Bernardinello, A.; Desai, T.; Ullschmied, J.; Skala, J.; Kralikova, B.; Krousky, E.; Juha, L.; Pfeifer, M.; Kadlec, Ch.; Mocek, T.; Präg, A.; Renner, O.; Cotelli, F.; Lora Lamia, C.; Zullini, A.

    2004-08-01

    Soft X-ray Contact Microscopy (SXCM) of Caenorhabditis elegans nematodes with typical length ~800 μ m and diameter ~30 μ m has been performed using the PALS laser source of wavelength λ = 1.314~μ m and pulse duration τ (FWHM) = 400 ps. Pulsed soft X-rays were generated using molybdenum and gold targets with laser intensities I ≥ 1014 W/cm2. Images have been recorded on PMMA photo resists and analyzed using an atomic force microscope operating in contact mode. Cuticle features and several internal organs have been identified in the SXCM images including lateral field, cuticle annuli, pharynx, and hypodermal and neuronal cell nuclei.

  4. Hard x-ray scanning microscopy with coherent radiation: Beyond the resolution of conventional x-ray microscopes

    SciTech Connect

    Schropp, A.; Hoppe, R.; Patommel, J.; Samberg, D.; Seiboth, F.; Stephan, S.; Schroer, C. G.; Wellenreuther, G.; Falkenberg, G.

    2012-06-18

    We demonstrate x-ray scanning coherent diffraction microscopy (ptychography) with 10 nm spatial resolution, clearly exceeding the resolution limits of conventional hard x-ray microscopy. The spatial resolution in a ptychogram is shown to depend on the shape (structure factor) of a feature and can vary for different features in the object. In addition, the resolution and contrast are shown to increase with increasing coherent fluence. For an optimal ptychographic x-ray microscope, this implies a source with highest possible brilliance and an x-ray optic with a large numerical aperture to generate the optimal probe beam.

  5. PREFACE: 9th International Conference on X-Ray Microscopy

    NASA Astrophysics Data System (ADS)

    Quitmann, Christoph; David, Christian; Nolting, Frithjof; Pfeiffer, Franz; Stampanoni, Marco

    2009-09-01

    Conference logo This volume compiles the contributions to the International Conference on X-Ray Microscopy (XRM2008) held on 20-25 July 2008 in Zurich, Switzerland. The conference was the ninth in a series which started in Göttingen in 1984. Over the years the XRM conference series has served as a forum bringing together all relevant players working on the development of methods, building instrumentation, and applying x-ray microscopy to challenging issues in materials science, condensed matter research, environmental science and biology. XRM2008 was attended by about 300 participants who followed 44 oral presentations and presented 220 posters. Conference photograph Figure 1: Participants of the XRM2008 conference gathered in front of the main building of the ETH-Zurich. The conference showed that x-ray microscopy has become a mature field resting on three pillars. The first are workhorse instruments available even to non-specialist users. These exist at synchrotron sources world-wide as well as in laboratories. They allow the application of established microscopy methods to solve scientific projects in areas as diverse as soil science, the investigation of cometary dust particles, magnetic materials, and the analysis of ancient parchments. Examples of all of these projects can be found in this volume. These instruments have become so well understood that now they are also commercially available. The second pillar is the continued development of methods. Methods like stroboscopic imaging, wet cells or high and low temperature environments add versatility to the experiments. Methods like phase retrieval and ptychographic imaging allow the retrieval of information which hitero was thought to be inaccessible. The third pillar is the extension of such instruments and methods to new photon sources. With x-ray free electron lasers on the horizon the XRM community is working to transfer their know-how to these novel sources which will offer unprecedented brightness and

  6. X-ray microscopy for neural circuit reconstruction

    NASA Astrophysics Data System (ADS)

    Mizutani, Haruo; Takeda, Yoshihiro; Momose, Atsushi; Takeuchi, Akihisa; Takagi, Toshihisa

    2009-09-01

    Neural circuits in the central nervous system build our various higher brain functions. However, little is known about mechanisms underlying neuronal information processing in the brain. Anatomical graph structures of real neural networks will provide us with fundamental views to elucidate them. We aim at developing a three-dimensional atlas of neural circuits using high resolution hard X-ray microscopy by synchrotron radiation. We stained neurons of a complete brain from a mouse by the Golgi-Cox method. The heavy metals used in our procedure enhanced X-ray absorption and phase contrast. 3D images of fibriform axons and dendrites of various neurons were reconstructed by back projection. X-ray microscopy with a Talbot interferometer demonstrated finer histological structures of pyramidal neurons in the hippocampus and the cerebral cortex. This observation probably serves as a foundation for achieving a mammalian Connectome Project (identifying complete wiring diagrams of the brain) with X-ray nano-tomography in the near future.

  7. Viewing spin structures with soft x-ray microscopy

    SciTech Connect

    Fischer, Peter

    2010-06-01

    The spin of the electron and its associated magnetic moment marks the basic unit for magnetic properties of matter. Magnetism, in particular ferromagnetism and antiferromagnetism is described by a collective order of these spins, where the interaction between individual spins reflects a competition between exchange, anisotropy and dipolar energy terms. As a result the energetically favored ground state of a ferromagnetic system is a rather complex spin configuration, the magnetic domain structure. Magnetism is one of the eldest scientific phenomena, yet it is one of the most powerful and versatile utilized physical effects in modern technologies, such as in magnetic storage and sensor devices. To achieve highest storage density, the relevant length scales, such as the bit size in disk drives is now approaching the nanoscale and as such further developments have to deal with nanoscience phenomena. Advanced characterization tools are required to fully understand the underlying physical principles. Magnetic microscopes using polarized soft X-rays offer a close-up view into magnetism with unique features, these include elemental sensitivity due to X-ray magnetic dichroism effects as contrast mechanism, high spatial resolution provided by state-of-the-art X-ray optics and fast time resolution limited by the inherent time structure of current X-ray sources, which will be overcome with the introduction of ultrafast and high brilliant X-ray sources.

  8. Evolution of titania nanotubes-supported WO{sub x} species by in situ thermo-Raman spectroscopy, X-ray diffraction and high resolution transmission electron microscopy

    SciTech Connect

    Cortes-Jacome, M.A.; Angeles-Chavez, C.; Morales, M.; Lopez-Salinas, E.; Toledo-Antonio, J.A.

    2007-10-15

    Structural evolution of WO{sub x} species on the surface of titania nanotubes was followed by in situ thermo-Raman spectroscopy. A total of 15 wt% of W atoms were loaded on the surface of a hydroxylated titania nanotubes by impregnation with ammonium metatungstate solution and then, the sample was thermally treated in a Linkam cell at different temperatures in nitrogen flow. The band characteristic of the W=O bond was observed at 962 cm{sup -1} in the dried sample, which vanished between 300 and 700 deg. C, and reappear again after annealing at 800 deg. C, along with a broad band centered at 935 cm{sup -1}, attributed to the v{sub 1} vibration of W=O in tetrahedral coordination. At 900 and 1000 deg. C, the broad band decomposed into four bands at 923, 934, 940 and 950 cm{sup -1}, corresponding to the symmetric and asymmetric vibration of W=O bonds in Na{sub 2}WO{sub 4} and Na{sub 2}W{sub 2}O{sub 7} phases as determined by X-ray diffraction and High resolution transmission electron microscopy (HRTEM). The structure of the nanotubular support was kept at temperatures below 450 deg. C, thereafter, it transformed into anatase being stabilized at temperatures as high as 900 deg. C. At 1000 deg. C, anatase phase partially converted into rutile. After annealing at 1000 deg. C, a core-shell model material was obtained, with a shell of ca. 5 nm thickness, composed of sodium tungstate nanoclusters, and a core composed mainly of rutile TiO{sub 2} phase. - Graphical abstract: Titania nanotubes loaded with 15 wt% W atoms were characterized from room temperature (rt) to 1000 deg. C by thermo-Raman spectroscopy in N{sub 2}. At 1000 deg. C, a core-shell model material was obtained, with a shell thickness of ca. 5 nm composed by nanoclusters of sodium tungstate, and a core composed mainly of rutile TiO{sub 2} phase.

  9. Elemental imaging of cartilage by scanning x-ray microscopy

    SciTech Connect

    Buckley, C.J.; Foster, G.F.; Burge, R.E. ); Ali, S.Y.; Scotchford, C.A. , Royal National Orthopaedic Hospital, Stanmore, Middlesex ); Kirz, J. ); Rivers, M.L. )

    1992-01-01

    Elemental imaging via scanning transmission x-ray microscopy (STXM) and scanning fluorescence x-ray microscopy (SFXM) has been used to image calcium deposits in cartilage. In the case of STXM, 0.1 {mu}m thick sections were imaged to investigate the proximity of calcium deposits in relation to chondrocyte cells. The resolution available was 0.5 {mu}m, and field widths of up to 25 {mu}m were used at this resolution. The resolution available in SFXM was 10 {mu}m, and field widths of up to 2 mm were used at this resolution on 5-{mu}m thick specimens. Together these techniques were used to map calcium deposits at the cellular level, and at the full tissue size level.

  10. X-ray fluorescence microscopy of olfactory receptor neurons

    NASA Astrophysics Data System (ADS)

    Dučić, T.; Breunig, E.; Schild, D.; Herbst, J.; Nováková, E.; Susini, J.; Tucoulu, R.; Salditt, T.

    2009-09-01

    We report a x-ray fluorescence microscopy study of cells and tissues from the olfactory system of Xenopus laevis. In this experiment we focus on sample preparation and experimental issues, and present first results of fluorescence maps of the elemental distribution of Cl, K, Ca, P, S and Na both in individual isolated neural cells and in cross-sections of the same tissue.

  11. Calcified-tissue investigations using synchrotron x-ray microscopy

    SciTech Connect

    Jones, K.W.; Spanne, P.; Schidlovsky, G.; Dejun, X. ); Bockman, R.S. . Medical Coll.); Rabinowitz, M.B. ); Hammond, P.B.; Bornschein, R.L. ); Hoeltzel, D.A. )

    1990-10-01

    Synchrotron x-ray microscopy (SXRM) in both emission and absorption modes has been used to examine elemental distributions in specimens of rat tibia, human deciduous teeth, and an orthopedic implant phantom. The work was performed with a spatial resolution of 8 {mu}m for the emission work and 25 {mu}m for the absorption work. The results illustrate the usefulness of SXRM for measurements of different types of calcified tissue. 3 figs.

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

    PubMed Central

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

    2010-01-01

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

  13. Hard-X-ray magnetic microscopy and local magnetization analysis using synchrotron radiation.

    PubMed

    Suzuki, Motohiro

    2014-11-01

    X-ray measurement offers several useful features that are unavailable from other microscopic means including electron-based techniques. By using X-rays, one can observe the internal parts of a thick sample. This technique basically requires no high vacuum environment such that measurements are feasible for wet specimens as well as under strong electric and magnetic fields and even at a high pressure. X-ray spectroscopy using core excitation provides element-selectivity with significant sensitivities to the chemical states and atomic magnetic moments in the matter. Synchrotron radiation sources produce a small and low-divergent X-ray beam, which can be converged to a spot with the size of a micrometer or less using X-ray focusing optics. The recent development in the focusing optics has been driving X-ray microscopy, which has already gone into the era of X-ray nanoscopy. With the use of the most sophisticated focusing devices, an X-ray beam of 7-nm size has successfully been achieved [1]. X-ray microscopy maintains above-mentioned unique features of X-ray technique, being a perfect complement to electron microscopy.In this paper, we present recent studies on magnetic microscopy and local magnetic analysis using hard X-rays. The relevant instrumentation developments are also described. The X-ray nanospectroscopy station of BL39XU at SPring-8 is equipped with a focusing optics consisting of two elliptic mirrors, and a focused X-ray beam with the size of 100 × 100 nm(2) is available [2]. Researchers can perform X-ray absorption spectroscopy: nano-XAFS (X-ray absorption fine structure) using the X-ray beam as small as 100 nm. The available X-ray energy is from 5 to 16 keV, which allows nano-XAFS study at the K edges of 3d transition metals, L edges of rare-earth elements and 5d noble metals. Another useful capability of the nanoprobe is X-ray polarization tunability, enabling magnetic circular dichroism (XMCD) spectroscopy with a sub-micrometer resolution. Scanning

  14. Ultrastructural and elemental imaging of biological specimens by soft x-ray contact microscopy

    SciTech Connect

    Panessa, B.J.; Hoffman, P. . Dept. of Orthopedics); Warren, J.B. ); Feder, R.; Sayre, D. . Thomas J. Watson Research Center)

    1980-01-01

    Soft X-ray contact microscopy offers a means of visualizing unstained as well as stained biological materials at better than 6 nm resolution. Soft X-ray imaging depends on differential absorption of incident soft (1--10nm wavelength) X-rays by the endogenous elements within a specimen. The advantages of using soft X-rays for imaging are: (1) reduced specimen damage during exposure; (2) ability to image hydrated specimens at atmospheric pressure; (3) ability to image specimens ranging in thickness from less than 40 nm to as much as 10{mu}m; and (4) ability to map the elemental composition of the specimen through observation of the differential absorption of properly chosen incident x-ray wavelengths. This paper explains the principles of image formation and demonstrates the use of soft X-ray contact microscopy with biological samples which could not readily be imaged in their natural form using conventional electron microscopy methods. Data are also presented on the recognition of compositional features in histochemically treated articular joint tissues. 30 refs., 15 figs.

  15. Development of scanning electron and x-ray microscope

    NASA Astrophysics Data System (ADS)

    Matsumura, Tomokazu; Hirano, Tomohiko; Suyama, Motohiro

    2016-01-01

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

  16. Vanderbilt University free-electron laser x-ray facility

    NASA Astrophysics Data System (ADS)

    Tompkins, Perry A.; Andrews, Weiwei D.; Brau, Charles A.; Waters, James A.; Carroll, Frank E.; Pickens, David R.; Price, Ronald R.; Roos, Carlton F.

    1993-02-01

    The Vanderbilt University Free-Electron Laser Program is developing the capability to create near-monochromatic x rays for medical imaging and other purposes. For this experiment we feed-back the normal infrared FEL light to collide with the electron beam. This causes Compton backscattering of the incident photons which creates x rays. These x rays cannot feed an x-ray laser, but they have a collimated intensity and tunability which make them highly suitable for medical imaging. This paper is particularly focused on the x-ray beam transport to be used with this experiment. This transport must collimate the x-ray beam and re-direct it to match a beam chase located in the vault ceiling at a 40 degree angle to the electron beam axis. A brief description of the creation mechanism and x-ray beam properties are included.

  17. Characterizing automotive fuel cell materials by soft x-ray scanning transmission x-ray microscopy

    NASA Astrophysics Data System (ADS)

    Hitchcock, A. P.; Lee, V.; Wu, J.; West, M. M.; Cooper, G.; Berejnov, V.; Soboleva, T.; Susac, D.; Stumper, J.

    2016-01-01

    Proton-Exchange Membrane Fuel Cell (PEM-FC) based engines are being developed rapidly for near-term implementation in hydrogen fueled, mass production, personal automobiles. Research is focused on understanding and controlling various degradation processes (carbon corrosion, Pt migration, cold start), and reducing cost by reducing or eliminating Pt catalyst. We are using soft X-ray scanning transmission X-ray microscopy (STXM) at the S 2p, C 1s, O 1s and F 1s edges to study a variety of issues related to optimization of PEM-FC materials for automotive applications. A method to efficiently and accurately measure perfluorosulfonic acid distributions was developed and is being used to better understand how different loadings and preparation methods affect the ionomer distribution in the cathode. Progress towards an environmental cell capable of controlling the temperature and humidity of a PEM-FC sample in the STXM is described. Methods for studying the 3D chemical structure of PEM-FC are outlined.

  18. X-ray Microscopy Resource Center at the Advanced Light Source

    SciTech Connect

    Meyer-Ilse, W.; Attwood, D.; Koike, M.

    1992-08-01

    The high spectral brightness of undulator radiation from the Advanced Light Source (ALS) offers a great scientific opportunity for biological x-ray microscopy. X-ray microscopy extends visible light microscopy to higher resolution and makes use of unique contrast mechanisms. It does not compete with techniques such as electron microscopy in terms of resolution, but rather offers unique advantages, including the opportunity to take images of samples in an aqueous environment. For a considerable range of resolution and sample thickness the radiation dose in x-ray microscopy is lower than in electron microscopy under the same imaging conditions. To exploit this opportunity a Biological X-ray Microscopy Resource Center will be built at the ALS. An x-ray microscope (XM) and a scanning x-ray microscope (SXM) are to be built. These two microscopes serve complementary needs. The XM gives high quality images at comparably short exposure times, while the SXM is optimized for low radiation dose. High resolution is accomplished in both microscopes with Fresnel zone plate lenses. The SXM produces a diffraction-limited focus point, which is scanned across the sample; therefore the SXM can use only the spatially coherent portion of the radiation. The SXM is best operated on an undulator source with its small phase space. An XM can use the full brightness, including the incoherent fraction of the source. It can be operated with either a bending magnet or an undulator source. The XM can be installed initially at a bending magnet, which can be available at an earlier time, and thus permits the development of diverse biological community at an earlier time. Later this XM can be moved to the undulator, or left at the bending magnet for developmental and less demanding experiments.

  19. High-resolution ab initio three-dimensional x-ray diffraction microscopy

    DOE PAGESBeta

    Chapman, Henry N.; Barty, Anton; Marchesini, Stefano; Noy, Aleksandr; Hau-Riege, Stefan P.; Cui, Congwu; Howells, Malcolm R.; Rosen, Rachel; He, Haifeng; Spence, John C. H.; et al

    2006-01-01

    Coherent x-ray diffraction microscopy is a method of imaging nonperiodic isolated objects at resolutions limited, in principle, by only the wavelength and largest scattering angles recorded. We demonstrate x-ray diffraction imaging with high resolution in all three dimensions, as determined by a quantitative analysis of the reconstructed volume images. These images are retrieved from the three-dimensional diffraction data using no a priori knowledge about the shape or composition of the object, which has never before been demonstrated on a nonperiodic object. We also construct two-dimensional images of thick objects with greatly increased depth of focus (without loss of transverse spatialmore » resolution). These methods can be used to image biological and materials science samples at high resolution with x-ray undulator radiation and establishes the techniques to be used in atomic-resolution ultrafast imaging at x-ray free-electron laser sources.« less

  20. High-resolution ab initio Three-dimensional X-ray Diffraction Microscopy

    SciTech Connect

    Chapman, H N; Barty, A; Marchesini, S; Noy, A; Cui, C; Howells, M R; Rosen, R; He, H; Spence, J H; Weierstall, U; Beetz, T; Jacobsen, C; Shapiro, D

    2005-08-19

    Coherent X-ray diffraction microscopy is a method of imaging non-periodic isolated objects at resolutions only limited, in principle, by the largest scattering angles recorded. We demonstrate X-ray diffraction imaging with high resolution in all three dimensions, as determined by a quantitative analysis of the reconstructed volume images. These images are retrieved from the 3D diffraction data using no a priori knowledge about the shape or composition of the object, which has never before been demonstrated on a non-periodic object. We also construct 2D images of thick objects with infinite depth of focus (without loss of transverse spatial resolution). These methods can be used to image biological and materials science samples at high resolution using X-ray undulator radiation, and establishes the techniques to be used in atomic-resolution ultrafast imaging at X-ray free-electron laser sources.

  1. High-resolution ab initio three-dimensional x-ray diffraction microscopy

    SciTech Connect

    Chapman, Henry N.; Barty, Anton; Marchesini, Stefano; Noy, Aleksandr; Hau-Riege, Stefan P.; Cui, Congwu; Howells, Malcolm R.; Rosen, Rachel; He, Haifeng; Spence, John C. H.; Weierstall, Uwe; Beetz, Tobias; Jacobsen, Chris; Shapiro, David

    2006-01-01

    Coherent x-ray diffraction microscopy is a method of imaging nonperiodic isolated objects at resolutions limited, in principle, by only the wavelength and largest scattering angles recorded. We demonstrate x-ray diffraction imaging with high resolution in all three dimensions, as determined by a quantitative analysis of the reconstructed volume images. These images are retrieved from the three-dimensional diffraction data using no a priori knowledge about the shape or composition of the object, which has never before been demonstrated on a nonperiodic object. We also construct two-dimensional images of thick objects with greatly increased depth of focus (without loss of transverse spatial resolution). These methods can be used to image biological and materials science samples at high resolution with x-ray undulator radiation and establishes the techniques to be used in atomic-resolution ultrafast imaging at x-ray free-electron laser sources.

  2. Laboratory source based full-field x-ray microscopy at 9 keV

    NASA Astrophysics Data System (ADS)

    Fella, C.; Balles, A.; Wiest, W.; Zabler, S.; Hanke, R.

    2016-01-01

    In the past decade, hard x-ray transmission microscopy experienced tremendous developments. With the avail-ability of efficient Fresnel zone plates, even set-ups utilizing laboratory sources were developed [1]. In order to improve the performance of these x-ray microscopes, novel approaches to fabricate optical elements [2] and brighter x-ray tubes [3] are promising candidates. We are currently building a laboratory transmission x-ray microscope for 9.25 keV, using an electron impact liquid-metal-jet anode source. Up to now, the further elements of our setup are: a polycapillary condenser, a tungsten zone plate, and a scintillator which is optically coupled to a CMOS camera. However, further variations in terms of optical elements are intended. Here we present the current status of our work, as well as first experimental results.

  3. Coherent x-ray zoom condenser lens for diffractive and scanning microscopy.

    PubMed

    Kimura, Takashi; Matsuyama, Satoshi; Yamauchi, Kazuto; Nishino, Yoshinori

    2013-04-22

    We propose a coherent x-ray zoom condenser lens composed of two-stage deformable Kirkpatrick-Baez mirrors. The lens delivers coherent x-rays with a controllable beam size, from one micrometer to a few tens of nanometers, at a fixed focal position. The lens is suitable for diffractive and scanning microscopy. We also propose non-scanning coherent diffraction microscopy for extended objects by using an apodized focused beam produced by the lens with a spatial filter. The proposed apodized-illumination method will be useful in highly efficient imaging with ultimate storage ring sources, and will also open the way to single-shot coherent diffraction microscopy of extended objects with x-ray free-electron lasers. PMID:23609637

  4. Determination of the size and phase composition of silver nanoparticles in a gel film of bacterial cellulose by small-angle X-ray scattering, electron diffraction, and electron microscopy

    NASA Astrophysics Data System (ADS)

    Volkov, V. V.; Klechkovskaya, V. V.; Shtykova, E. V.; Dembo, K. A.; Arkharova, N. A.; Ivakin, G. I.; Smyslov, R. Yu.

    2009-03-01

    The nanoscale structural features in a composite (gel film of Acetobacter Xylinum cellulose with adsorbed silver nanoparticles, stabilized by N-polyvinylpyrrolidone) have been investigated by small-angle X-ray scattering. The size distributions of inhomogeneities in the porous structure of the cellulose matrix and the size distributions of silver nanoparticles in the composite have been determined. It is shown that the sizes of synthesized nanoparticles correlate with the sizes of inhomogeneities in the gel film. Particles of larger size (with radii up to 100 nm) have also been found. Electron microscopy of thin cross sections of a dried composite layer showed that large particles are located on the cellulose layer surface. Electron diffraction revealed a crystal structure of silver nanoparticles in the composite.

  5. Determination of the size and phase composition of silver nanoparticles in a gel film of bacterial cellulose by small-angle X-ray scattering, electron diffraction, and electron microscopy

    SciTech Connect

    Volkov, V. V.; Klechkovskaya, V. V. Shtykova, E. V.; Dembo, K. A.; Arkharova, N. A.; Ivakin, G. I.; Smyslov, R. Yu.

    2009-03-15

    The nanoscale structural features in a composite (gel film of Acetobacter Xylinum cellulose with adsorbed silver nanoparticles, stabilized by N-polyvinylpyrrolidone) have been investigated by small-angle X-ray scattering. The size distributions of inhomogeneities in the porous structure of the cellulose matrix and the size distributions of silver nanoparticles in the composite have been determined. It is shown that the sizes of synthesized nanoparticles correlate with the sizes of inhomogeneities in the gel film. Particles of larger size (with radii up to 100 nm) have also been found. Electron microscopy of thin cross sections of a dried composite layer showed that large particles are located on the cellulose layer surface. Electron diffraction revealed a crystal structure of silver nanoparticles in the composite.

  6. A soft X-ray beamline for transmission X-ray microscopy at ALBA.

    PubMed

    Pereiro, E; Nicolás, J; Ferrer, S; Howells, M R

    2009-07-01

    The MISTRAL beamline is one of the seven phase-I beamlines at the ALBA synchrotron light source (Barcelona, Spain) that will be opened to users at the end of 2010. MISTRAL will be devoted to cryotomography in the water window and multi-keV spectral regions for biological applications. The optics design consists of a plane-grating monochromator that has been implemented using variable-line-spacing gratings to fulfil the requirements of X-ray microscopy using a reflective condenser. For instance, a fixed-focus condition independent of the included angle, constant magnification as well as coma and spherical aberration corrections are achieved with this system. The reported design is of wider use. PMID:19535865

  7. The Development of Hard X-ray Microscopy with MIRRORCLE-6X

    NASA Astrophysics Data System (ADS)

    Hirai, T.; Tokunaga, T.; Yamada, H.; Sasaki, M.; Hasegawa, D.; Ogasaka, Y.; Yamashita, H.

    2004-08-01

    A laboratory-scale hard X-ray microscope utilizing the portable synchrotron named MIRRORCLE-6X is developed in our laboratory. MIRRORCLE-6X is a X-ray source suitable for hard X-ray microscopy as a result of the X-ray source size of the order of micron, and highly brilliant hard X-rays. Furthermore, when effective focusing elements of hard X-rays are used for MIRRORCLE-6X, this machine could be used for non destructive inspection with high resolution of biological and engineering. We designed hard X-ray optical elements for MIRRORCLE6X and started fabricating X-ray mirrors.

  8. Simultaneous X-ray fluorescence and scanning X-ray diffraction microscopy at the Australian Synchrotron XFM beamline.

    PubMed

    Jones, Michael W M; Phillips, Nicholas W; van Riessen, Grant A; Abbey, Brian; Vine, David J; Nashed, Youssef S G; Mudie, Stephen T; Afshar, Nader; Kirkham, Robin; Chen, Bo; Balaur, Eugeniu; de Jonge, Martin D

    2016-09-01

    Owing to its extreme sensitivity, quantitative mapping of elemental distributions via X-ray fluorescence microscopy (XFM) has become a key microanalytical technique. The recent realisation of scanning X-ray diffraction microscopy (SXDM) meanwhile provides an avenue for quantitative super-resolved ultra-structural visualization. The similarity of their experimental geometries indicates excellent prospects for simultaneous acquisition. Here, in both step- and fly-scanning modes, robust, simultaneous XFM-SXDM is demonstrated. PMID:27577770

  9. Characterization of toners and inkjets by laser ablation spectrochemical methods and Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy

    NASA Astrophysics Data System (ADS)

    Trejos, Tatiana; Corzo, Ruthmara; Subedi, Kiran; Almirall, José

    2014-02-01

    Detection and sourcing of counterfeit currency, examination of counterfeit security documents and determination of authenticity of medical records are examples of common forensic document investigations. In these cases, the physical and chemical composition of the ink entries can provide important information for the assessment of the authenticity of the document or for making inferences about common source. Previous results reported by our group have demonstrated that elemental analysis, using either Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS) or Laser Ablation Induced Breakdown Spectroscopy (LIBS), provides an effective, practical and robust technique for the discrimination of document substrates and writing inks with minimal damage to the document. In this study, laser-based methods and Scanning Electron Microscopy-Energy Dispersive X-Ray Spectroscopy (SEM-EDS) methods were developed, optimized and validated for the forensic analysis of more complex inks such as toners and inkjets, to determine if their elemental composition can differentiate documents printed from different sources and to associate documents that originated from the same printing source. Comparison of the performance of each of these methods is presented, including the analytical figures of merit, discrimination capability and error rates. Different calibration strategies resulting in semi-quantitative and qualitative analysis, comparison methods (match criteria) and data analysis and interpretation tools were also developed. A total of 27 black laser toners originating from different manufacturing sources and/or batches were examined to evaluate the discrimination capability of each method. The results suggest that SEM-EDS offers relatively poor discrimination capability for this set (~ 70.7% discrimination of all the possible comparison pairs or a 29.3% type II error rate). Nonetheless, SEM-EDS can still be used as a complementary method of analysis since it has

  10. Soft X-ray Microscopy of Green Cements

    NASA Astrophysics Data System (ADS)

    Monteiro, P. J. M.; Mancio, M.; Kirchheim, A. P.; Chae, R.; Ha, J.; Fischer, P.; Tyliszczak, T.

    2011-09-01

    The present status of the cement and concrete industry is not sustainable. The production of Portland cement is responsible for 7% of the CO2 emissions in the world and existing reinforced concrete infrastructure is deteriorating at a fast pace. The change in the existing technology requires new developments in our understanding of the nanostructure of hydration products and the complex deterioration reactions. We have been developing an elaborate research program to advance the existing cement and concrete science by characterizing its nanostructure by synchrotron radiation. A new generation of green cements is being studied using high-resolution soft x-ray microscopy at the nano-level.

  11. Scattering imaging method in transmission x-ray microscopy.

    PubMed

    Chen, Jian; Gao, Kun; Ge, Xin; Wang, Zhili; Zhang, Kai; Hong, Youli; Pan, Zhiyun; Wu, Zhao; Zhu, Peiping; Yun, Wenbing; Wu, Ziyu

    2013-06-15

    We present a x-ray microscopy technique based on structured illumination in a microscope that characterizes the size of the subresolution-limit features. The technique is effective for characterizing fine structures substantially beyond the Rayleigh resolution of the microscope. We carried out optical experiments to demonstrate the basic principle of this new technique. Experimental results show good agreement with theoretical predictions. This technique should find a wide range of important imaging applications with a feature size down to nanometer scale, such as oil and gas reservoir rocks, advanced composites, and functional nanodevices and materials. PMID:23938979

  12. Soft X-ray Microscopy of Green Cements

    SciTech Connect

    Monteiro, P. J. M.; Mancio, M.; Chae, R.; Ha, J.; Kirchheim, A. P.; Fischer, P.; Tyliszczak, T.

    2011-09-09

    The present status of the cement and concrete industry is not sustainable. The production of Portland cement is responsible for 7% of the CO{sub 2} emissions in the world and existing reinforced concrete infrastructure is deteriorating at a fast pace. The change in the existing technology requires new developments in our understanding of the nanostructure of hydration products and the complex deterioration reactions. We have been developing an elaborate research program to advance the existing cement and concrete science by characterizing its nanostructure by synchrotron radiation. A new generation of green cements is being studied using high-resolution soft x-ray microscopy at the nano-level.

  13. Soft X-ray microscopy to characterize polyelectrolyte assemblies.

    PubMed

    Köhler, Karen; Déjugnat, Christophe; Dubois, Monique; Zemb, Thomas; Sukhorukov, Gleb B; Guttmann, Peter; Möhwald, Helmuth

    2007-07-26

    Transmission microscopy with soft X-rays (TXM) is applied to image in-situ polyelectrolyte assemblies in aqueous environment. The method is element specific and at this stage exhibits a lateral resolution of 20 nm. With the specific examples of hollow capsules and full spheres made of PAH/PSS polyelectrolyte multilayers, it is shown quantitatively that heat treatment irreversibly reduces the water content in the membrane. These experiments complement those reported recently on the polyion system PDADMAC/PSS, which shows a different glass-transition behavior. Finally, the potential and present limitations of TXM are discussed. PMID:17428089

  14. X-ray microscopy of soft and hard human tissues

    NASA Astrophysics Data System (ADS)

    Müller, Bert; Schulz, Georg; Deyhle, Hans; Stalder, Anja K.; Ilgenstein, Bernd; Holme, Margaret N.; Weitkamp, Timm; Beckmann, Felix; Hieber, Simone E.

    2016-01-01

    The simultaneous post mortem visualization of soft and hard tissues using absorption-based CT remains a challenge. If the photon energy is optimized for the visualization of hard tissue, the surrounding soft tissue components are almost X-ray transparent. Therefore, the combination with other modalities such as phase-contrast CT, magnetic resonance microscopy, and histology is essential to detect the anatomical features. The combination of the 2D and 3D data sets using sophisticated segmentation and registration tools allows for conclusions about otherwise inaccessible anatomical features essential for improved patient treatments.

  15. Electronic and geometric properties of Au nanoparticles on Highly Ordered Pyrolytic Graphite (HOPG) studied using X-ray Photoelectron Spectroscopy (XPS) and Scanning Tunneling Microscopy (STM).

    PubMed

    Lopez-Salido, Ignacio; Lim, Dong Chan; Dietsche, Rainer; Bertram, Nils; Kim, Young Dok

    2006-01-26

    Au nanoparticles grown on mildly sputtered Highly Ordered Pyrolytic Graphite (HOPG) surfaces were studied using Scanning Tunneling Microscopy (STM) and X-ray Photoelectron Spectroscopy (XPS). The results were compared with those of Ag nanoparticles on the same substrate. By varying the defect densities of HOPG and the Au coverages, one can create Au nanoparticles in various sizes. At high Au coverages, the structures of the Au films significantly deviate from the ideal truncated octahedral form: the existence of many steps between different Au atomic layers can be observed, most likely due to a high activation barrier of the diffusion of Au atoms across the step edges. This implies that the particle growth at room temperature is strongly limited by kinetic factors. Hexagonal shapes of Au structures could be identified, indicating preferential growth of Au nanostructures along the (111) direction normal to the surface. In the case of Au, XPS studies reveal a weaker core level shift with decreasing particle size compared to the 3d level in similarly sized Ag particles. Also taking into account the Auger analysis of the Ag particles, the core level shifts of the metal nanoparticles on HOPG can be understood in terms of the metal/substrate charge transfer. Ag is (partially) positively charged, whereas Au negatively charged on HOPG. It is demonstrated that XPS can be a useful tool to study metal-support interactions, which plays an important role for heterogeneous catalysis, for example. PMID:16471654

  16. Nanoscale chemical imaging using synchrotron x-ray enhanced scanning tunneling microscopy

    SciTech Connect

    Rose, Volker; Freeland, John W.

    2010-06-23

    The combination of synchrotron radiation with scanning tunneling microscopy provides a promising new concept for chemical imaging of nanoscale structures. It employs detection of local x-ray absorption, which directly yields chemical, electronic, and magnetic sensitivity. The study of the tip current in the far field (800 nm tip/sample separation) shows that insulator-coated tips have to be considered in order to reduce the background from stray photoelectron. A picture of the different channels contributing to the x-ray enhanced STM process is proposed. If during electron tunneling the sample is illuminated with monochromatic x-rays, characteristic absorption will arise, and core electrons are excited, which might modulate the conventional tunnel current and facilitate chemical imaging at the nanoscale.

  17. Zone-Doubled Fresnel Zone Plates for Scanning Transmission X-ray Microscopy

    NASA Astrophysics Data System (ADS)

    Vila-Comamala, J.; Gorelick, S.; Färm, E.; Kewish, C. M.; Diaz, A.; Guzenko, V. A.; Barrett, R.; Raabe, J.; Menzel, A.; Bunk, O.; Ritala, M.; David, C.

    2011-09-01

    We demonstrate the highest spatial resolution reported in scanning transmission x-ray microscopy to date. For the first time in x-ray microscopy, features below 10 nm in width were resolved in the soft x-ray regime (1.2 keV) and 20-nm lines and spaces were visible at multi-keV photon energies (6.2 keV). These achievements were accomplished using zone-doubled Fresnel zone plates. These lenses were fabricated by combining electron-beam lithography and atomic layer deposition of iridium. Diffraction efficiencies up to 8% were measured for zone-doubled Fresnel zone plates with an outermost zone width of 25 nm at 6.2-keV photon energy.

  18. Fundamental studies of X-ray and secondary electron spectroscopy

    NASA Astrophysics Data System (ADS)

    Mulapudi, Satya Prasad

    Microanalysis of submicron particles in the Scanning Electron Microscope (SEM) is only possible by using low incident electron beam energies due to smaller interaction volume and suppressed beam induced charging. Such low beam energies must use L- and M-lines rather than the familiar K-lines. The information about the fundamental parameters of X-ray emission and transport at low energies is limited, so the use of L- and M-lines is problematic. The rate of generation of X-rays from an element irradiated at some energy E depends on the product of the ionization cross-section sigma(E) and the fluorescent yield o. Unfortunately neither of these quantities is well established independently, especially outside of the K-series of lines. Therefore the absolute X-ray generation efficiencies (photons/electron) were directly measured and parameterized for a wide range of K, L , and M lines from different elements. It is anticipated that a complete set of such data would be of great value in applications such as spectrum simulation and standardless analysis. Secondary electron spectra have been collected from both pure elements and from compounds examined under conditions approximating those found in a scanning electron microscope. Despite the presence of substantial surface contamination these spectra are found to be reproducible and characteristic of the underlying material. Typically the peak in such spectra is found to be at an energy of about 5 eV, and 50% of the total secondary electron emission falls within the range 0--12 eV. These data may be of value for the design of detectors for scanning microscopy and might have applications for microanalysis.

  19. Low dose, limited energy spectroscopic x-ray microscopy

    NASA Astrophysics Data System (ADS)

    Nelson Weker, Johanna; Li, Yiyang; Chueh, William C.

    2015-09-01

    In order to achieve high quality in situ spectroscopic X-ray microscopy of complex systems far from equilibrium, such as lithium ion batteries under standard electrochemical cycling, careful consideration of the total number of energy points is required. Enough energy points are need to accurately determine the per pixel chemical information; however, total radiation dose needs to be limited to avoid damaging the system which would produce misleading results. Here we consider the number of energy points need to accurately reproduce the state of charge maps of a LiFePO2 electrode recorded during electrochemical cycling. We observe very good per pixel agreement using only 13 energy points. Additionally, we find the quality of the agreement is heavily dependent on the number of energy points used in the post edge fit during normalization of the spectra rather than the total number of energies used. Finally, we suggest a straightforward protocol for determining the minimum number of energy points needed prior to initiating any in situ spectroscopic X-ray microscopy experiment.

  20. Imaging at high spatial resolution: Soft x-ray microscopy to 15nm

    SciTech Connect

    Attwood, D.; Chao, W.; Anderson, E.; Liddle, J.A.; Harteneck, B.; Fischer, P.; Schneider, G.; Le Gros, M.; Larabell, C.

    2006-04-05

    Soft x-ray microscopy has now achieved 15 nm spatial resolution with new zone plates and bending magnet radiation. Combined with elemental sensitivity and flexible sample environment (applied magnetic or electric fields, wet samples, windows, overcoatings) this emerges as a valuable tool for nanoscience and nanotechnology, complimenting common electron and scanning tip microscopies. In this presentation we describe recent advances in spatial resolution, expectations for the near future, and applications to magnetic materials, bio-tomography, etc.

  1. Examination of Libby, Montana, Fill Material for Background Levels of Amphibole from the Rainy Creek Complex Using Scanning Electron Microscopy and X-Ray Microanalysis

    USGS Publications Warehouse

    Adams, David T.; Langer, William H.; Hoefen, Todd M.; Van Gosen, Bradley S.; Meeker, Gregory P.

    2010-01-01

    Natural background levels of Libby-type amphibole in the sediment of the Libby valley in Montana have not, up to this point, been determined. The purpose of this report is to provide the preliminary findings of a study designed by both the U.S. Geological Survey and the U.S. Environmental Protection Agency and performed by the U.S. Geological Survey. The study worked to constrain the natural background levels of fibrous amphiboles potentially derived from the nearby Rainy Creek Complex. The material selected for this study was sampled from three localities, two of which are active open-pit sand and gravel mines. Seventy samples were collected in total and examined using a scanning electron microscope equipped with an energy dispersive x-ray spectrometer. All samples contained varying amounts of feldspars, ilmenite, magnetite, quartz, clay minerals, pyroxene minerals, and non-fibrous amphiboles such as tremolite, actinolite, and magnesiohornblende. Of the 70 samples collected, only three had detectable levels of fibrous amphiboles compatible with those found in the rainy creek complex. The maximum concentration, identified here, of the amphiboles potentially from the Rainy Creek Complex is 0.083 percent by weight.

  2. Structure of low-density nanoporous dielectrics revealed by low-vacuum electron microscopy and small-angle x-ray scattering

    SciTech Connect

    Kucheyev, S O; Toth, M; Baumann, T F; Hamza, A V; Ilavsky, J; Knowles, W R; Thiel, B L; Tileli, V; van Buuren, T; Wang, Y M; Willey, T M

    2006-06-05

    We use low-vacuum scanning electron microscopy to image directly the ligament and pore size and shape distributions of representative aerogels over a wide range of length scales ({approx} 10{sup 0}-10{sup 5} nm). The images are used for unambiguous, real-space interpretation of small-angle scattering data for these complex nanoporous systems.

  3. Density gradient free electron collisionally excited x-ray laser

    DOEpatents

    Campbell, E.M.; Rosen, M.D.

    1984-11-29

    An operational x-ray laser is provided that amplifies 3p-3s transition x-ray radiation along an approximately linear path. The x-ray laser is driven by a high power optical laser. The driving line focused optical laser beam illuminates a free-standing thin foil that may be associated with a substrate for improved structural integrity. This illumination produces a generally cylindrically shaped plasma having an essentially uniform electron density and temperature, that exists over a long period of time, and provides the x-ray laser gain medium. The x-ray laser may be driven by more than one optical laser beam. The x-ray laser has been successfully demonstrated to function in a series of experimental tests.

  4. Density gradient free electron collisionally excited X-ray laser

    DOEpatents

    Campbell, Edward M.; Rosen, Mordecai D.

    1989-01-01

    An operational X-ray laser (30) is provided that amplifies 3p-3s transition X-ray radiation along an approximately linear path. The X-ray laser (30) is driven by a high power optical laser. The driving line focused optical laser beam (32) illuminates a free-standing thin foil (34) that may be associated with a substrate (36) for improved structural integrity. This illumination produces a generally cylindrically shaped plasma having an essentially uniform electron density and temperature, that exists over a long period of time, and provides the X-ray laser gain medium. The X-ray laser (30) may be driven by more than one optical laser beam (32, 44). The X-ray laser (30) has been successfully demonstrated to function in a series of experimental tests.

  5. Preparation of tissue samples for X-ray fluorescence microscopy

    NASA Astrophysics Data System (ADS)

    Chwiej, Joanna; Szczerbowska-Boruchowska, Magdalena; Lankosz, Marek; Wojcik, Slawomir; Falkenberg, Gerald; Stegowski, Zdzislaw; Setkowicz, Zuzanna

    2005-12-01

    As is well-known, trace elements, especially metals, play an important role in the pathogenesis of many disorders. The topographic and quantitative elemental analysis of pathologically changed tissues may shed some new light on processes leading to the degeneration of cells in the case of selected diseases. An ideal and powerful tool for such purpose is the Synchrotron Microbeam X-ray Fluorescence technique. It enables the carrying out of investigations of the elemental composition of tissues even at the single cell level. The tissue samples for histopathological investigations are routinely fixed and embedded in paraffin. The authors try to verify the usefulness of such prepared tissue sections for elemental analysis with the use of X-ray fluorescence microscopy. Studies were performed on rat brain samples. Changes in elemental composition caused by fixation in formalin or paraformaldehyde and embedding in paraffin were examined. Measurements were carried out at the bending magnet beamline L of the Hamburger Synchrotronstrahlungslabor HASYLAB in Hamburg. The decrease in mass per unit area of K, Br and the increase in P, S, Fe, Cu and Zn in the tissue were observed as a result of the fixation. For the samples embedded in paraffin, a lower level of most elements was observed. Additionally, for these samples, changes in the composition of some elements were not uniform for different analyzed areas of rat brain.

  6. Development of X-ray Microscopy at IPOE

    SciTech Connect

    Zhu, J.; Mu, B.; Huang, Q.; Huang, C.; Yi, S.; Zhang, Z.; Wang, F.; Wang, Z.; Chen, L.

    2011-09-09

    In order to meet the different requirements of applications in synchrotron radiation and plasma diagnosis in China, focusing and imaging optics based on Kirkpatrick-Baez (KB) mirrors, compound refractive lenses (CRLs), and multilayer Laue lenses (MLLs) were studied in our lab. A one-dimensional KB microscope using mirrors with a dual-periodic multilayer coating was developed. The multilayer mirror can reflect both 4.75 keV (Ti K-line) and 8.05 keV (Cu K-line) simultaneously, which makes alignment easier. For hard x-ray microscopy, CRL was studied. Using a SU-8 resist planar parabolic CRL, a focal line of 28.8-{mu}m width was obtained. To focus hard x-rays to nanometer levels efficiently, an MLL was fabricated using a WSi{sub 2}/Si multilayer. The MLL consists of 324 alternating WSi{sub 2} and Si layers with a total thickness of 7.9 {mu}m. (Recently, a much thicker multilayer has been deposited with a layer number of n = 1582 and a total thickness of 27 {mu}m.) After deposition, the sample was sliced and polished into an approximate ideal aspect ratio (depth of the zone plate to outmost layer thickness); the measured results show an intact structure remains, and the surface roughness of the cross section is about 0.4 nm after grinding and polishing processes.

  7. Electron beam welder X-rays its own welds

    NASA Technical Reports Server (NTRS)

    Roden, W. A.

    1967-01-01

    Beam of an electron beam welder X rays its own welds, enabling rapid weld quality checks to be made without removing the work from the vacuum chamber. A tungsten target produces X rays when hit by the beam. They are directed at the weld specimen and recorded on polaroid film.

  8. X-Ray-Diffraction Tests Of Irradiated Electronic Devices: II

    NASA Technical Reports Server (NTRS)

    Shaw, David C.; Lowry, Lynn E.; Barnes, Charles E.

    1993-01-01

    Report describes research on use of x-ray diffraction to measure stresses in metal conductors of complementary metal oxide/semiconductor (CMOS) integrated circuits exposed to ionizing radiation. Expanding upon report summarized in "X-Ray-Diffraction Tests Of Irradiated Electronic Devices: I" (NPO-18803), presenting data further suggesting relationship between electrical performances of circuits and stresses and strains in metal conductors.

  9. Scanning and transmission electron microscopy and X-ray analysisof leaf salt glands of Limoniastrum guyonianum Boiss. under NaCl salinity.

    PubMed

    Zouhaier, Barhoumi; Abdallah, Atia; Najla, Trabelsi; Wahbi, Djebali; Wided, Chaïbi; Aouatef, Ben Ammar; Chedly, Abdelly; Abderazzak, Smaoui

    2015-11-01

    Leaf salt glands of Limoniastrum guyonianum were examined by scanning and transmission electron microscopes and energy dispersive X-ray analysis (EDAX) system, after growing for three months on sandy soil with or without 300 mM NaCl. Results showed that salt glands were irregularly scattered on both leaf sides and sunk under the epidermal level. Salt excretion occurred in both conditions and is mainly composed of calcium and magnesium in control plants, and essentially sodium and chloride in plants subjected to salt treatment. A salt gland is comprised of collecting, accumulating, and central compartments, and is made up of total thirty-two cells. The collecting cells were characterized by large central vacuoles. Accumulating cells contain numerous, large, and unshaped vacuoles and rudimentary chloroplasts. The central compartment was comprised of four basal cells and each one is surmounted by an apical cell. The basal cells are granulated, containing large nucleus, numerous mitochondria, endoplasmic reticulum, ribosomes, polyribosomes, and small vacuoles or vesicles. Equally, the apical cells are rich in organelles. Application of 300 mM NaCl to the culture medium increased vacuoles number and size, and organelles density especially the mitochondria which suggests energy requirement for ions transport. The reduction in size and number of vacuoles toward the interior of salt glands of treated plants and the fusion of the smallest ones with the plasma membrane substantiate the implication of such vacuoles in salt excretion process. The current study which is the first report on L. guyonianum salt gland has provided an in-depth understanding on structure-function relationship in the multicellular salt glands. PMID:26102605

  10. [Based on Curing Age of Calcined Coal Gangue Fine Aggregate Mortar of X-Ray Diffraction and Scanning Electron Microscopy Analysis].

    PubMed

    Dong, Zuo-chao; Xia, Jun-wu; Duan, Xiao-mu; Cao, Ji-chang

    2016-03-01

    By using X-ray diffraction (XRD) and environmental scanning electron microscope (SEM) analysis method, we stud- ied the activity of coal gangue fine aggregate under different calcination temperature. In view of the activity of the highest-700 degrees C high temperature calcined coal gangue fine aggregate mortar of hydration products, microstructure and strength were discussed in this paper, and the change laws of mortar strength with curing age (3, 7, 14, 28, 60 and 90 d) growth were analyzed. Test results showed that coal gangue fine aggregate with the increase of calcination temperature, the active gradually increases. When the calcination temperature reaches 700 degrees C, the activity of coal gangue fine aggregate is the highest. When calcining temperature continues to rise, activity falls. After 700 degrees C high temperature calcined coal gangue fine aggregate has obvious ash activity, the active components of SiO2 and Al2 O3 can be with cement hydration products in a certain degree of secondary hydration reaction. Through on the top of the activity of different curing age 700 degrees C high temperature calcined coal gangue fine aggregate mortar, XRD and SEM analysis showed that with the increase of curing age, secondary hydration reaction will be more fully, and the amount of hydration products also gradually increases. Compared with the early ages of the cement mortar, the products are more stable hydration products filling in mortar microscopic pore, which can further improve the microstructure of mortar, strengthen the interface performance of the mortar. The mortar internal structure is more uniform, calcined coal gangue fine aggregate and cement mortar are more of a strong continuous whole, which increase the later strength of hardened cement mortar, 700 degrees C high temperature calcined coal gangue fine aggregate pozzolanic effect is obvious. PMID:27400535

  11. X-ray tube with magnetic electron steering

    DOEpatents

    Reed, Kim W.; Turman, Bobby N.; Kaye, Ronald J.; Schneider, Larry X.

    2000-01-01

    An X-ray tube uses a magnetic field to steer electrons. The magnetic field urges electrons toward the anode, increasing the proportion of electrons emitted from the cathode that reach desired portions of the anode and consequently contribute to X-ray production. The magnetic field also urges electrons reflected from the anode back to the anode, further increasing the efficiency of the tube.

  12. X-ray framing camera for pulsed, high current, electron beam x-ray sources

    NASA Astrophysics Data System (ADS)

    Failor, B. H.; Rodriguez, J. C.; Riordan, J. C.; Lojewski, D. Y.

    2007-07-01

    High power x-ray sources built for nuclear weapons effects testing are evolving toward larger overall diameters and smaller anode cathode gaps. We describe a framing camera developed to measure the time-evolution of these 20-50 ns pulsed x-ray sources produced by currents in the 1.5-2.5 MA range and endpoint voltages between 0.2 and 1.5 MV. The camera has up to 4 frames with 5 ns gate widths; the frames are separated by 5 ns. The image data are recorded electronically with a gated intensified CCD camera and the data are available immediately following a shot. A fast plastic scintillator (2.1 ns decay time) converts the x-rays to visible light and, for high sensitivity, a fiber optic imaging bundle carries the light to the CCD input. Examples of image data are shown.

  13. X-Ray Fluorescence Microscopy for Investigation of Archival Tissues

    PubMed Central

    Paunesku, T.; Wanzer, M. B.; Kirillova, E. N.; Muksinova, K. N.; Revina, V. S.; Romanov, S. A.; Lyubchansky, E. R.; Grosche, B.; Birschwilks, M.; Vogt, S.; Finney, L.; Woloschak, G. E.

    2013-01-01

    Several recent efforts in radiation biology community worldwide have amassed records and archival tissues from animals exposed to different radionuclides and external beam irradiation. In most cases, these samples come from life-long studies on large animal populations conducted in national laboratories and equivalent institutions throughout Europe, North America, and Japan. While many of these tissues were used for histopathological analyses, much more information may still be obtained from these samples. A new technique suitable for imaging of these tissues is X-Ray Fluorescence Microscopy (XFM). Following development of third generation synchrotrons, XFM has emerged as an ideal technique for study of metal content, speciation, and localization in cells, tissues and organs. Here we review some of the recent XFM literature pertinent to tissue sample studies and present examples of XFM data obtained from tissue sections of beagle dog samples which show that the quality of archival tissues allows XFM investigation. PMID:22951477

  14. Observation of Organelles in Leydig Cells by Contact Soft X-Ray Microscopy with a Laser Plasma X-Ray Source

    NASA Astrophysics Data System (ADS)

    Kado, M.; Ishino, M.; Tamotsu, S.; Yasuda, K.; Kishimoto, M.; Nishikino, M.; Kinjo, Y.; Shinohara, K.

    2011-09-01

    We observed the same biological specimens for comparison of the images by contact soft x-ray microscopy with a laser plasma x-ray source with those by confocal laser microscopy. Images of wet Leydig cells were directly comparable for organelles and showed that actin filaments and mitochondria were clearly identified in the soft x-ray images.

  15. Femtosecond X-ray magnetic circular dichroism absorption spectroscopy at an X-ray free electron laser.

    PubMed

    Higley, Daniel J; Hirsch, Konstantin; Dakovski, Georgi L; Jal, Emmanuelle; Yuan, Edwin; Liu, Tianmin; Lutman, Alberto A; MacArthur, James P; Arenholz, Elke; Chen, Zhao; Coslovich, Giacomo; Denes, Peter; Granitzka, Patrick W; Hart, Philip; Hoffmann, Matthias C; Joseph, John; Le Guyader, Loïc; Mitra, Ankush; Moeller, Stefan; Ohldag, Hendrik; Seaberg, Matthew; Shafer, Padraic; Stöhr, Joachim; Tsukamoto, Arata; Nuhn, Heinz-Dieter; Reid, Alex H; Dürr, Hermann A; Schlotter, William F

    2016-03-01

    X-ray magnetic circular dichroism spectroscopy using an X-ray free electron laser is demonstrated with spectra over the Fe L(3,2)-edges. The high brightness of the X-ray free electron laser combined with high accuracy detection of incident and transmitted X-rays enables ultrafast X-ray magnetic circular dichroism studies of unprecedented sensitivity. This new capability is applied to a study of all-optical magnetic switching dynamics of Fe and Gd magnetic sublattices in a GdFeCo thin film above its magnetization compensation temperature. PMID:27036761

  16. Femtosecond X-ray magnetic circular dichroism absorption spectroscopy at an X-ray free electron laser

    NASA Astrophysics Data System (ADS)

    Higley, Daniel J.; Hirsch, Konstantin; Dakovski, Georgi L.; Jal, Emmanuelle; Yuan, Edwin; Liu, Tianmin; Lutman, Alberto A.; MacArthur, James P.; Arenholz, Elke; Chen, Zhao; Coslovich, Giacomo; Denes, Peter; Granitzka, Patrick W.; Hart, Philip; Hoffmann, Matthias C.; Joseph, John; Le Guyader, Loïc; Mitra, Ankush; Moeller, Stefan; Ohldag, Hendrik; Seaberg, Matthew; Shafer, Padraic; Stöhr, Joachim; Tsukamoto, Arata; Nuhn, Heinz-Dieter; Reid, Alex H.; Dürr, Hermann A.; Schlotter, William F.

    2016-03-01

    X-ray magnetic circular dichroism spectroscopy using an X-ray free electron laser is demonstrated with spectra over the Fe L3,2-edges. The high brightness of the X-ray free electron laser combined with high accuracy detection of incident and transmitted X-rays enables ultrafast X-ray magnetic circular dichroism studies of unprecedented sensitivity. This new capability is applied to a study of all-optical magnetic switching dynamics of Fe and Gd magnetic sublattices in a GdFeCo thin film above its magnetization compensation temperature.

  17. Atmospheric electron-induced x-ray spectrometer development

    NASA Technical Reports Server (NTRS)

    Wilcox, Jaroslava Z.; Urgiles, Eduardo; Toda, Risaku; Crisp, Joy

    2005-01-01

    This paper extends the work reported at the IEEE Aerospace conference in 2001 and 2003 where the concept and progress in the development of the so called atmospheric Electron X-ray Spectrometer (AEXS) has been described.

  18. Limitations of ZAF correction factors in the determination of calcium/phosphorus ratios: Important forensic science considerations relevant to the analysis of bone fragments using scanning electron microscopy and energy-dispersive x-ray microanalysis

    SciTech Connect

    Payne, C.M.; Cromey, D.W. )

    1990-05-01

    A series of calcium phosphate standards having calcium/phosphorus (Ca/P) molar ratios of 0.50, 1.00, 1.50, and 1.67, respectively, was prepared for bulk specimen analysis using scanning electron microscopy (SEM) and energy-dispersive X-ray microanalysis (EDXA). The standards were mounted on carbon planchettes as either pure crystals or crystals embedded in epoxy resin. Ten different samples of each embedded and non-embedded standard were analyzed in a JEOL 100 CX electron microscope interfaced with a Kevex 8000 EDXA system using a lithium-drifted silicon detector and a multichannel analyzer. The Ca/P ratios were determined by calculating both net peak intensities without matrix corrections and atomic kappa-ratios using the MAGIC V computer program with ZAF correction factors for quantitative analysis. There was such extensive absorption of phosphorus X-rays in standards embedded in an epoxy matrix that the observed Ca/P ratios were statistically compatible with four different standards ranging in theoretical Ca/P ratios from 1.0 to 1.67. Although the non-embedded crystals showed a greater separation in the Ca/P ratios, both methods of preparation produced serious flaws in analysis. Direct application of the discovery of this caveat to the identification of suspected bone fragments for forensic science purposes is discussed.

  19. Combined x-ray photoelectron spectroscopy and scanning electron microscopy studies of the LiBH4-MgH2 reactive hydride composite with and without a Ti-based additive

    NASA Astrophysics Data System (ADS)

    Deprez, E.; Muñoz-Márquez, M. A.; Jimenez de Haro, M. C.; Palomares, F. J.; Soria, F.; Dornheim, M.; Bormann, R.; Fernández, A.

    2011-01-01

    A detailed electronic and microstructural characterization is reported for the LiBH4-MgH2 reactive hydride composite system with and without titanium isopropoxide as additive. Surface characterization by x-ray photoelectron spectroscopy combined to a morphological study by scanning electron microscopy as well as elemental map composition analysis by energy dispersive x-ray emission are presented in this paper for the first time for all sorption steps. Although sorption reactions are not complete at the surface due to the unavoidable superficial oxidation, it has been shown that the presence of the additive is favoring the heterogeneous nucleation of the MgB2 phase. Ti-based phases appear in all the samples for the three sorption steps well dispersed and uniformly distributed in the material. Li-based phases are highly dispersed at the surface while the Mg-based ones appear, either partially covered by the Li-based phases, or forming bigger grains. Ball milling is promoting mixing of phases and a good dispersion of the additive what favors grain refinement and heterogeneous reactions at the interfaces.

  20. Hard X-ray Imaging Microscopy using X-ray Guide Tube as Beam Condenser for Field Illumination

    NASA Astrophysics Data System (ADS)

    Suzuki, Yoshio; Takeuchi, Akihisa; Uesugi, Kentaro; Terada, Yasuko; Nakazawa, Hiromoto; Ohzawa, Sumito; Aoyama, Tomoki; Nii, Hajime; Handa, Katsumi

    2013-10-01

    An optical system for illumination of object in x-ray imaging microscopy is developed. The optical system is a beam condenser consisting of a single-bounce conical-shape mono-capillary (x-ray guide tube: XGT) made of Pyrex glass. The XGT condenser was tested at the beam line 47XU of SPring-8 using a Fresnel zone plate as an objective lens. Comparing with the microscope without beam condenser, the flux density is improved by a factor of 12-20 in the x-ray energy range of 6-8 keV. Test patterns with a 50 nm-structure are clearly resolved at 8 keV with an exposure time less than 1 s.

  1. The Combination of X-Ray Crystallography and Cryo-Electron Microscopy Provides Insight into the Overall Architecture of the Dodecameric Rvb1/Rvb2 Complex

    PubMed Central

    Glatt, Sebastian; Hoffmann, Niklas A.; Kastritis, Panagiotis; Bork, Peer; Beck, Martin; Müller, Christoph W.

    2016-01-01

    The Rvb1/Rvb2 complex is an essential component of many cellular pathways. The Rvb1/Rvb2 complex forms a dodecameric assembly where six copies of each subunit form two heterohexameric rings. However, due to conformational variability, the way the two rings pack together is still not fully understood. Here, we present the crystal structure and two cryo-electron microscopy reconstructions of the dodecameric, full-length Rvb1/Rvb2 complex, all showing that the interaction between the two heterohexameric rings is mediated through the Rvb1/Rvb2-specific domain II. Two conformations of the Rvb1/Rvb2 dodecamer are present in solution: a stretched conformation also present in the crystal, and a compact conformation. Novel asymmetric features observed in the reconstruction of the compact conformation provide additional insight into the plasticity of the Rvb1/Rvb2 complex. PMID:26745716

  2. Semi-automatic detection of gunshot residue (GSR) by scanning electron microscopy and energy dispersive X-ray analysis (SEM/EDX).

    PubMed

    Gansau, H; Becker, U

    1982-01-01

    Wide strips of adhesive tape (40 mm x 86 mm) are pressed for about one minute on the thumb, forefinger and outer edge of a subject's hand. Subsequently these tapes are fixed to a cylinder that rotates within the SEM chamber and is adjustable in an axial direction. The tapes are scanned for possible GSR particles with simultaneous SE and X-ray imaging. The X-ray signal caused by particles of high atomic number automatically stops the rotating cylinder, and the EDX spectrum of the suspect particle is produced within five seconds. A chart is then plotted to record the size, elemental composition, morphology and tape coordinates of the particles of interest. The outcome is a complete map of GSR particles found on certain parts of the hand, and this map has a characteristic pattern depending on the firearm used, the ammunition and the circumstances of the shooting incident. The time lapse between firing and sampling may allow this GSR pattern to change, but this method is helpful in suicide/homicide decisions. PMID:7167744

  3. Application of x-ray nano-particulate markers for the visualization of intermediate layers and interfaces using scanning electron microscopy

    NASA Astrophysics Data System (ADS)

    Bessudnova, Nadezda O.; Bilenko, David I.; Zakharevich, Andrey M.

    2012-03-01

    In this study the methodology of biological sample preparation for dental research using SEM/EDX has been elaborated. (1)The original cutting equipment supplied with 3D user-controlled sample fixation and an adjustable cooling system has been designed and evaluated. (2) A new approach to the root dentine drying procedure has been developed to preserve structure peculiarities of root dentine. (3) A novel adhesive system with embedded X-Ray nanoparticulate markers has been designed. (4)The technique allowing for visualization of bonding resins, interfaces and intermediate layers between tooth hard tissues and restorative materials of endodontically treated teeth using the X-ray nano-particulate markers has been developed and approved. These methods and approaches were used to compare the objective depth of penetration of adhesive systems of different generations in root dentine. It has been shown that the depth of penetration in dentine is less for adhesive systems of generation VI in comparison with bonding resins of generation V, which is in agreement with theoretical evidence. The depth of penetration depends on the correlation between the direction of dentinal tubules, bonding resin delivery and gravity.

  4. Application of x-ray nano-particulate markers for the visualization of intermediate layers and interfaces using scanning electron microscopy

    NASA Astrophysics Data System (ADS)

    Bessudnova, Nadezda O.; Bilenko, David I.; Zakharevich, Andrey M.

    2011-10-01

    In this study the methodology of biological sample preparation for dental research using SEM/EDX has been elaborated. (1)The original cutting equipment supplied with 3D user-controlled sample fixation and an adjustable cooling system has been designed and evaluated. (2) A new approach to the root dentine drying procedure has been developed to preserve structure peculiarities of root dentine. (3) A novel adhesive system with embedded X-Ray nanoparticulate markers has been designed. (4)The technique allowing for visualization of bonding resins, interfaces and intermediate layers between tooth hard tissues and restorative materials of endodontically treated teeth using the X-ray nano-particulate markers has been developed and approved. These methods and approaches were used to compare the objective depth of penetration of adhesive systems of different generations in root dentine. It has been shown that the depth of penetration in dentine is less for adhesive systems of generation VI in comparison with bonding resins of generation V, which is in agreement with theoretical evidence. The depth of penetration depends on the correlation between the direction of dentinal tubules, bonding resin delivery and gravity.

  5. Microbial biofilm study by synchrotron X-ray microscopy

    NASA Astrophysics Data System (ADS)

    Pennafirme, S.; Lima, I.; Bitencourt, J. A.; Crapez, M. A. C.; Lopes, R. T.

    2015-11-01

    Microbial biofilm has already being used to remove metals and other pollutants from wastewater. In this sense, our proposal was to isolate and cultivate bacteria consortia from mangrove's sediment resistant to Zn (II) and Cu (II) at 50 mg L-1 and to observe, through synchrotron X-ray fluorescence microscopy (microXRF), whether the biofilm sequestered the metal. The biofilm area analyzed was 1 mm2 and a 2D map was generated (pixel size 20×20 μm2, counting time 5 s/point). The biofilm formation and retention followed the sequence Zn>Cu. Bacterial consortium zinc resistant formed dense biofilm and retained 63.83% of zinc, while the bacterial consortium copper resistant retained 3.21% of copper, with lower biofilm formation. Dehydrogenase activity of Zn resistant bacterial consortium was not negatively affect by 50 mg ml-1 zinc input, whereas copper resistant bacterial consortium showed a significant decrease on dehydrogenase activity (50 mg mL-1 of Cu input). In conclusion, biofilm may protect bacterial cells, acting as barrier against metal toxicity. The bacterial consortia Zn resistant, composed by Nitratireductor spp. and Pseudomonas spp formed dense biofilm and sequestered metal from water, decreasing the metal bioavailability. These bacterial consortia can be used in bioreactors and in bioremediation programs.

  6. The identification of the pigments used to paint statues of Feixiange Cliff in China in late 19th century by micro-Raman spectroscopy and scanning electron microscopy/energy dispersive X-ray analysis

    NASA Astrophysics Data System (ADS)

    Jin, Pu-jun; Huang, Wei; Jianhua-Wang; Zhao, Gang; Wang, Xiao-ling

    2010-11-01

    The application of micro-Raman spectroscopy (μ-RS) and scanning electron microscopy (SEM)/energy dispersive X-ray spectrometer (EDS) to the research of pigments collected from Statues of Feixiange Cliff No. 67 and No. 69 niche of Tang Dynasty in China is reported. Five kinds of pigments were found in the experimental data, including black (carbon), white (gypsum + quartz), blue (lapis lazuli) and green (Paris green + Barium sulphate). After synthesized in 1814, Paris green was reported for a large import as a light and bright green pigment to paint architectures in China from the late 19th century. The analyzed blue pigment demonstrated the similar Raman spectra to the Lâjvardina blue glazed ceramics, which indicated lapis lazuli was an artificial product. This confirmed the painting of Feixiange Cliff in the early Republic of China as the historical record, and also reveals that some pigments were imported from abroad.

  7. Low dose hard x-ray contact microscopy assisted by a photoelectric conversion layer

    SciTech Connect

    Gomella, Andrew; Martin, Eric W.; Lynch, Susanna K.; Wen, Han; Morgan, Nicole Y.

    2013-04-15

    Hard x-ray contact microscopy provides images of dense samples at resolutions of tens of nanometers. However, the required beam intensity can only be delivered by synchrotron sources. We report on the use of a gold photoelectric conversion layer to lower the exposure dose by a factor of 40 to 50, allowing hard x-ray contact microscopy to be performed with a compact x-ray tube. We demonstrate the method in imaging the transmission pattern of a type of hard x-ray grating that cannot be fitted into conventional x-ray microscopes due to its size and shape. Generally the method is easy to implement and can record images of samples in the hard x-ray region over a large area in a single exposure, without some of the geometric constraints associated with x-ray microscopes based on zone-plate or other magnifying optics.

  8. Biological imaging by soft X-ray diffraction microscopy

    NASA Astrophysics Data System (ADS)

    Shapiro, David

    We have developed a microscope for soft x-ray diffraction imaging of dry or frozen hydrated biological specimens. This lensless imaging system does not suffer from the resolution or specimen thickness limitations that other short wavelength microscopes experience. The microscope, currently situated at beamline 9.0.1 of the Advanced Light Source, can collect diffraction data to 12 nm resolution with 750 eV photons and 17 nm resolution with 520 eV photons. The specimen can be rotated with a precision goniometer through an angle of 160 degrees allowing for the collection of nearly complete three-dimensional diffraction data. The microscope is fully computer controlled through a graphical user interface and a scripting language automates the collection of both two-dimensional and three-dimensional data. Diffraction data from a freeze-dried dwarf yeast cell, Saccharomyces cerevisiae carrying the CLN3-1 mutation, was collected to 12 run resolution from 8 specimen orientations spanning a total rotation of 8 degrees. The diffraction data was phased using the difference map algorithm and the reconstructions provide real space images of the cell to 30 nm resolution from each of the orientations. The agreement of the different reconstructions provides confidence in the recovered, and previously unknown, structure and indicates the three dimensionality of the cell. This work represents the first imaging of the natural complex refractive contrast from a whole unstained cell by the diffraction microscopy method and has achieved a resolution superior to lens based x-ray tomographic reconstructions of similar specimens. Studies of the effects of exposure to large radiation doses were also carried out. It was determined that the freeze-dried cell suffers from an initial collapse, which is followed by a uniform, but slow, shrinkage. This structural damage to the cell is not accompanied by a diminished ability to see small features in the specimen. Preliminary measurements on frozen

  9. 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

  10. High resolution chemical mapping via scanning transmission x-ray microscopy

    NASA Astrophysics Data System (ADS)

    Fleckenstein, Holger

    Scanning transmission x-ray microscopy (STXM) combines imaging at sub-50 nanometer spatial resolution in the soft x-ray region with x-ray absorption spectroscopy at an energy resolution of 0.1 eV and better. The sensitivity to light elements and their chemical bonding states in the near-edge x-ray absorption region together with 2D microscopy allow to map out the chemical composition of microscopic samples. Over the past decades STXM has been used by scientists from various fields such as material sciences, biology, earth and environmental sciences. This thesis describes the upgrade of the STXM microscopes at the National Synchrotron Light Source in Brookhaven National Laboratory. The now 5 th generation was a retrofit of the existing microscopes with a three axes laser interferometer system for improved relative sample positioning. Included in the same project were a hardware change towards faster scan positioning and data acquisition electronics as well as a new software concept allowing for remote control of the microscopes. We also present the use of non-negative matrix factorization to analyze spectromicroscopic data sets. Since in many specimens of interest in biology or related fields a number of spectral signatures may be unknown, thickness maps of the chemical composition of a sample cannot be calculated directly. A previous method used principal component analysis to orthogonalize and noise filter spectromicroscopy data, followed by cluster analysis as a form of unsupervised pattern recognition to determine pixels with spectroscopic similarity. We tried a non-negative matrix factorization algorithm to find a parts-based representation of the same data. The non-negativity constraint allows for a physical interpretation of component spectra and thickness maps. The STXM technique was utilized to investigate the composition of human sperm samples. We describe why the analysis of human sperm via x-ray spectromicroscopy can provide valuable information and what

  11. An X-ray microscopy perspective on the effect of glutaraldehyde fixation on cells.

    PubMed

    Jearanaikoon, S; Abraham-Peskir, J V

    2005-05-01

    X-ray microscopy (XRM) is the only microscopy technique that can provide high-resolution (30 nm) imaging of biological specimens without the need to fix, stain or section them. We aim to determine the effect, if any, of glutaraldehyde fixation on algae cells from the XRM perspective and thus provide beneficial information for both X-ray and electron microscopists on artefacts induced by glutaraldehyde fixation. Three species of microalgae, Microcystis aeruginosa, Anabaena spiroides and Chlorella vulgaris, were used in this study. XRM images were obtained from unfixed and glutaraldehyde-fixed cells and cell diameter and percentage X-ray absorbency were measured. The mean diameter of cells from fixed preparations was smaller than from unfixed preparations; the mean diameter of M. aeruginosa cells was significantly reduced from 3.92 microm in unfixed cells to 3.43 microm in fixed cells (P < 0.05); in C. vulgaris the diameter of cells was also significantly reduced from 3.50 microm in unfixed to 2.98 microm in fixed samples (P < 0.05); whereas there was no significant reduction in the diameter of A. spiroides cells (4.04-3.90 microm). The protein crosslinking mechanism of glutaraldehyde probably generated free water molecules, which play an important role in radiation damage induced by X-rays. This was seen as mass loss and cell shrinkage, which in the present study occurred more frequently in fixed cells than in unfixed cells. In addition, we demonstrated that the uptake of glutaraldehyde by cells makes all protein constituents in the cell organize into a closely packed configuration, thus causing a rise in the percentage of X-ray absorbency. In fixed cells, this rise was approximately by a factor of two compared with unfixed samples in which protein constituents inside the cell are arranged in their native form. PMID:15857380

  12. Study of Interactions Between Microbes and Minerals by Scanning Transmission X-Ray Microscopy (STXM)

    SciTech Connect

    Benzerara, K.; Tyliszczak, T.; Brown, G.E., Jr.; /Stanford U., Geo. Environ. Sci. /SLAC, SSRL

    2007-01-03

    Scanning Transmission X-ray Microscopy (STXM) and Transmission Electron Microscopy (TEM) were combined to characterize various samples of geomicrobiological interest down to the nanometer scale. An approach based on energy-filtered imaging was used to examine microbe-mineral interactions and the resulting biominerals, as well as biosignatures in simplified laboratory samples. This approach was then applied to natural samples, including natural biofilms entombed in calcium carbonate precipitates and bioweathered silicates and facilitated location of bacterial cells and provided unique insights about their biogeochemical interactions with minerals at the 30-40 nm scale.

  13. Simultaneous cryo X-ray ptychographic and fluorescence microscopy of green algae.

    PubMed

    Deng, Junjing; Vine, David J; Chen, Si; Nashed, Youssef S G; Jin, Qiaoling; Phillips, Nicholas W; Peterka, Tom; Ross, Rob; Vogt, Stefan; Jacobsen, Chris J

    2015-02-24

    Trace metals play important roles in normal and in disease-causing biological functions. X-ray fluorescence microscopy reveals trace elements with no dependence on binding affinities (unlike with visible light fluorophores) and with improved sensitivity relative to electron probes. However, X-ray fluorescence is not very sensitive for showing the light elements that comprise the majority of cellular material. Here we show that X-ray ptychography can be combined with fluorescence to image both cellular structure and trace element distribution in frozen-hydrated cells at cryogenic temperatures, with high structural and chemical fidelity. Ptychographic reconstruction algorithms deliver phase and absorption contrast images at a resolution beyond that of the illuminating lens or beam size. Using 5.2-keV X-rays, we have obtained sub-30-nm resolution structural images and ∼90-nm-resolution fluorescence images of several elements in frozen-hydrated green algae. This combined approach offers a way to study the role of trace elements in their structural context. PMID:25675478

  14. Simultaneous cryo X-ray ptychographic and fluorescence microscopy of green algae

    SciTech Connect

    Deng, Junjing; Vine, David J.; Chen, Si; Nashed, Youssef S. G.; Jin, Qiaoling; Phillips, Nicholas W.; Peterka, Tom; Ross, Rob; Vogt, Stefan; Jacobsen, Chris J.

    2015-02-24

    Trace metals play important roles in normal and in disease-causing biological functions. X-ray fluorescence microscopy reveals trace elements with no dependence on binding affinities (unlike with visible light fluorophores) and with improved sensitivity relative to electron probes. However, X-ray fluorescence is not very sensitive for showing the light elements that comprise the majority of cellular material. Here we show that X-ray ptychography can be combined with fluorescence to image both cellular structure and trace element distribution in frozen-hydrated cells at cryogenic temperatures, with high structural and chemical fidelity. Ptychographic reconstruction algorithms deliver phase and absorption contrast images at a resolution beyond that of the illuminating lens or beam size. Using 5.2-keV X-rays, we have obtained sub–30-nm resolution structural images and ~90-nm–resolution fluorescence images of several elements in frozen-hydrated green algae. This combined approach offers a way to study the role of trace elements in their structural context.

  15. Simultaneous cryo X-ray ptychographic and fluorescence microscopy of green algae

    DOE PAGESBeta

    Deng, Junjing; Vine, David J.; Chen, Si; Nashed, Youssef S. G.; Jin, Qiaoling; Phillips, Nicholas W.; Peterka, Tom; Ross, Rob; Vogt, Stefan; Jacobsen, Chris J.

    2015-02-24

    Trace metals play important roles in normal and in disease-causing biological functions. X-ray fluorescence microscopy reveals trace elements with no dependence on binding affinities (unlike with visible light fluorophores) and with improved sensitivity relative to electron probes. However, X-ray fluorescence is not very sensitive for showing the light elements that comprise the majority of cellular material. Here we show that X-ray ptychography can be combined with fluorescence to image both cellular structure and trace element distribution in frozen-hydrated cells at cryogenic temperatures, with high structural and chemical fidelity. Ptychographic reconstruction algorithms deliver phase and absorption contrast images at a resolutionmore » beyond that of the illuminating lens or beam size. Using 5.2-keV X-rays, we have obtained sub–30-nm resolution structural images and ~90-nm–resolution fluorescence images of several elements in frozen-hydrated green algae. This combined approach offers a way to study the role of trace elements in their structural context.« less

  16. Soft X-ray scanning transmission X-ray microscopy (STXM) of actinide particles.

    PubMed

    Nilsson, Hans J; Tyliszczak, Tolek; Wilson, Richard E; Werme, Lars; Shuh, David K

    2005-09-01

    A descriptive account is given of our most recent research on the actinide dioxides with the Advanced Light Source Molecular Environmental Science (ALS-MES) Beamline 11.0.2 soft X-ray scanning transmission X-ray microscope (STXM) at the Lawrence Berkeley National Laboratory (LBNL). The ALS-MES STXM permits near-edge X-ray absorption fine structure (NEXAFS) and imaging with 30-nm spatial resolution. The first STXM spectromicroscopy NEXAFS spectra at the actinide 4d5/2 edges of the imaged transuranic particles, NpO2 and PuO2, have been obtained. Radiation damage induced by the STXM was observed in the investigation of a mixed oxidation state particle (Np(V,VI)) and was minimized during collection of the actual spectra at the 4d5/2 edge of the Np(V,VI) solid. A plutonium elemental map was obtained from an irregular PuO2 particle with the dimensions of 650 x 650 nm. The Pu 4d5/2 NEXAFS spectra were collected at several different locations from the PuO2 particle and were identical. A representative oxygen K-edge spectrum from UO2 was collected and resembles the oxygen K-edge from the bulk material. The unique and current performance of the ALS-MES STXM at extremely low energies (ca. 100 eV) that may permit the successful measurement of the actinide 5d edge is documented. Finally, the potential of STXM as a tool for actinide investigations is briefly discussed. PMID:16021423

  17. Correlative VIS-fluorescence and soft X-ray cryo-microscopy/tomography of adherent cells.

    PubMed

    Hagen, Christoph; Guttmann, Peter; Klupp, Barbara; Werner, Stephan; Rehbein, Stefan; Mettenleiter, Thomas C; Schneider, Gerd; Grünewald, Kay

    2012-02-01

    Soft X-ray cryo-microscopy/tomography of vitreous samples is becoming a valuable tool in structural cell biology. Within the 'water-window' wavelength region (2.34-4.37nm), it provides absorption contrast images with high signal to noise ratio and resolution of a few tens of nanometer. Soft X-rays with wavelengths close to the K-absorption edge of oxygen penetrate biological samples with thicknesses in the micrometer range. Here, we report on the application of a recently established extension of the transmission soft X-ray cryo-microscope (HZB TXM) at the beamline U41-XM of the BESSY II electron storage ring by an in-column epi-fluorescence and reflected light cryo-microscope. We demonstrate the new capability for correlative fluorescence and soft X-ray cryo-microscopy/tomography of this instrument along a typical life science experimental approach - the correlation of a fluorophore-tagged protein (pUL34-GFP of pseudorabies virus, PrV, the nuclear membrane-anchored component of the nuclear egress complex of the Herpesviridae which interacts with viral pUL31) in PrV pUL34-GFP/pUL31 coexpressing mammalian cells, with virus-induced vesicular structures in the nucleus, expanding the nucleoplasmic reticulum. Taken together, our results demonstrate new possibilities to study the role of specific proteins in substructures of adherent cells, especially of the nucleus in toto, accessible to electron microscopy in thinned samples only. PMID:22210307

  18. Correlative VIS-fluorescence and soft X-ray cryo-microscopy/tomography of adherent cells

    PubMed Central

    Hagen, Christoph; Guttmann, Peter; Klupp, Barbara; Werner, Stephan; Rehbein, Stefan; Mettenleiter, Thomas C.; Schneider, Gerd; Grünewald, Kay

    2012-01-01

    Soft X-ray cryo-microscopy/tomography of vitreous samples is becoming a valuable tool in structural cell biology. Within the ‘water-window’ wavelength region (2.34–4.37 nm), it provides absorption contrast images with high signal to noise ratio and resolution of a few tens of nanometer. Soft X-rays with wavelengths close to the K-absorption edge of oxygen penetrate biological samples with thicknesses in the micrometer range. Here, we report on the application of a recently established extension of the transmission soft X-ray cryo-microscope (HZB TXM) at the beamline U41-XM of the BESSY II electron storage ring by an in-column epi-fluorescence and reflected light cryo-microscope. We demonstrate the new capability for correlative fluorescence and soft X-ray cryo-microscopy/tomography of this instrument along a typical life science experimental approach – the correlation of a fluorophore-tagged protein (pUL34-GFP of pseudorabies virus, PrV, the nuclear membrane-anchored component of the nuclear egress complex of the Herpesviridae which interacts with viral pUL31) in PrV pUL34-GFP/pUL31 coexpressing mammalian cells, with virus-induced vesicular structures in the nucleus, expanding the nucleoplasmic reticulum. Taken together, our results demonstrate new possibilities to study the role of specific proteins in substructures of adherent cells, especially of the nucleus in toto, accessible to electron microscopy in thinned samples only. PMID:22210307

  19. Femtosecond x-ray absorption spectroscopy with hard x-ray free electron laser

    SciTech Connect

    Katayama, Tetsuo; Togashi, Tadashi; Tono, Kensuke; Kameshima, Takashi; Inubushi, Yuichi; Sato, Takahiro; Hatsui, Takaki; Yabashi, Makina; Obara, Yuki; Misawa, Kazuhiko; Bhattacharya, Atanu; Kurahashi, Naoya; Ogi, Yoshihiro; Suzuki, Toshinori

    2013-09-23

    We have developed a method of dispersive x-ray absorption spectroscopy with a hard x-ray free electron laser (XFEL), generated by a self-amplified spontaneous emission (SASE) mechanism. A transmission grating was utilized for splitting SASE-XFEL light, which has a relatively large bandwidth (ΔE/E ∼ 5 × 10{sup −3}), into several branches. Two primary split beams were introduced into a dispersive spectrometer for measuring signal and reference spectra simultaneously. After normalization, we obtained a Zn K-edge absorption spectrum with a photon-energy range of 210 eV, which is in excellent agreement with that measured by a conventional wavelength-scanning method. From the analysis of the difference spectra, the noise ratio was evaluated to be ∼3 × 10{sup −3}, which is sufficiently small to trace minute changes in transient spectra induced by an ultrafast optical laser. This scheme enables us to perform single-shot, high-accuracy x-ray absorption spectroscopy with femtosecond time resolution.

  20. Inelastic X-ray Scattering Studies of Electronic Excitations

    NASA Astrophysics Data System (ADS)

    Ishii, Kenji; Tohyama, Takami; Mizuki, Jun'ichiro

    2013-02-01

    Inelastic x-ray scattering (IXS) has developed into one of the most powerful momentum-resolved spectroscopies. Especially in the last decade, it has achieved significant progress utilizing brilliant x-rays from third-generation synchrotron radiation facilities. Simultaneously, theoretical efforts have been made to predict or interpret the experimental spectra. One of the scientific fields studied intensively by IXS is strongly correlated electron systems, where the interplay of charge, spin, and orbital degrees of freedom determines their physical properties. IXS can provide a new insight into the electron dynamics of the systems through the observation of charge, spin, and orbital excitations. Focusing on the momentum-resolved electronic excitations in strongly correlated electron systems, we review IXS studies and the present capabilities of IXS for the study of the dynamics of materials. With nonresonant inelastic x-ray scattering (NIXS), one can directly obtain dynamical charge correlation and we discuss its complementary aspects with inelastic neutron scattering. NIXS also has a unique capability of measuring higher multipole transitions, which are usually forbidden in conventional optical absorption. Resonant inelastic x-ray scattering (RIXS) is now established as a valuable tool for measuring charge, spin, and orbital excitations in a momentum-resolved manner. We describe RIXS works on cuprates in detail and show what kind of electronic excitations have been observed. We also discuss RIXS studies on other transition-metal compounds. Finally, we conclude with an outlook on IXS using next-generation x-ray sources.

  1. Ultrastructural imaging and molecular modeling of live bacteria using soft x-ray contact microscopy with nanoseconds laser plasma radiation

    SciTech Connect

    Kado, M.; Richardson, M.C.; Gabel, K.; Torres, D.; Rajyaguru, J.; Muszynski, M.J.

    1995-12-31

    Detection for clinical diagnosis and study of microbial cell is performed by a combination of low magnification optical microscopy and direct and indirect labeling techniques. Visual ultrastructural studies on subcellular organelles are possible with variations of electron microscopy (thin section, scanning and freeze fracture), although specimen preparation steps such as fixation, dehydration, resin embedding, ultra-thin sectioning, coating and staining are very specialized, extensive and may introduce artifacts in the original sample. The development of high resolution x-ray microscopy is a new technique well suited to observe the intact structure of a biological specimen at high resolution without any artifacts. Here, x ray images of the various live bacteria, such as Staphylococcus and Streptococcus, and micromolecule such as chromosomal DNA from Escherichia coli, and Lipopolysaccharide from Burkholderia cepacia, are obtained with soft x-ray contact microscopy. A compact tabletop type glass laser system is used to produce x rays from Al, Si, and Au targets. The PMMA photoresists are used to record x-ray images. An AFM (atomic force microscope) is used to reproduce the x-ray images from the developed photoresists. The performance of the 50 nm spatial resolutions are achieved and images are able to be discussed on the biological view.

  2. Combined X-ray Microfluorescence and Atomic Force Microscopy Studies of Mg Distribution in Whole Cells

    SciTech Connect

    Lagomarsino, S.; Farruggia, G.; Trapani, V.; Mastrototaro, L.; Wolf, F.; Cedola, A.; Fratini, M.; Notargiacomo, A.; Bukreeva, I.; McNulty, I.; Vogt, S.; Kim, S.; Legnini, D.; Maier, J. A. M.

    2011-09-09

    We present in this paper a novel methodology that combines scanning x-ray fluorescencee microscopy and atomic force microscopy. The combination of these two techniques allows the determination of a concentration map of Mg in whole (not sectioned) cells.

  3. Exotic X-ray Sources from Intermediate Energy Electron Beams

    SciTech Connect

    Chouffani, K.; Wells, D.; Harmon, F.; Jones, J.L.; Lancaster, G.

    2003-08-26

    High intensity x-ray beams are used in a wide variety of applications in solid-state physics, medicine, biology and material sciences. Synchrotron radiation (SR) is currently the primary, high-quality x-ray source that satisfies both brilliance and tunability. The high cost, large size and low x-ray energies of SR facilities, however, are serious limitations. Alternatively, 'novel' x-ray sources are now possible due to new small linear accelerator (LINAC) technology, such as improved beam emittance, low background, sub-Picosecond beam pulses, high beam stability and higher repetition rate. These sources all stem from processes that produce Radiation from relativistic Electron beams in (crystalline) Periodic Structures (REPS), or the periodic 'structure' of laser light. REPS x-ray sources are serious candidates for bright, compact, portable, monochromatic, and tunable x-ray sources with varying degrees of polarization and coherence. Despite the discovery and early research into these sources over the past 25 years, these sources are still in their infancy. Experimental and theoretical research are still urgently needed to answer fundamental questions about the practical and ultimate limits of their brightness, mono-chromaticity etc. We present experimental results and theoretical comparisons for three exotic REPS sources. These are Laser-Compton Scattering (LCS), Channeling Radiation (CR) and Parametric X-Radiation (PXR)

  4. Magnetic x-ray microscopy at low temperatures - Visualization of flux distributions in superconductors

    NASA Astrophysics Data System (ADS)

    Stahl, Claudia; Ruoß, Stephen; Weigand, Markus; Bechtel, Michael; Schütz, Gisela; Albrecht, Joachim

    2016-01-01

    X-ray Magnetic Circular Dichroism (XMCD) microscopy at liquid nitrogen temperature has been performed on bilayers of high-Tc superconducting YBCO (YBa2Cu3O7-δ) and soft-magnetic Co40Fe40B20. This should allow us to map the magnetic flux density distribution in the current-carrying state of the superconductor with high spatial resolution. For that purpose the UHV scanning X-ray microscope MAXYMUS has been upgraded by a MMR Micro Miniature Joule-Thompson cryostat capable of temperatures between 75 K and 580 K. Resulting XMCD images of the magnetic flux density in the superconductor with a field of view ranging from millimeters to micrometers are presented. The microscope's unique combination of total electron yield (TEY) measurements together with low temperatures offers novel possibilities concerning the current transport in superconductors on small length scales.

  5. X-ray and Electron Spectroscopy of Water.

    PubMed

    Fransson, Thomas; Harada, Yoshihisa; Kosugi, Nobuhiro; Besley, Nicholas A; Winter, Bernd; Rehr, John J; Pettersson, Lars G M; Nilsson, Anders

    2016-07-13

    Here we present an overview of recent developments of X-ray and electron spectroscopy to probe water at different temperatures. Photon-induced ionization followed by detection of electrons from either the O 1s level or the valence band is the basis of photoelectron spectroscopy. Excitation between the O 1s and the unoccupied states or occupied states is utilized in X-ray absorption and X-ray emission spectroscopies. These techniques probe the electronic structure of the liquid phase and show sensitivity to the local hydrogen-bonding structure. Both experimental aspects related to the measurements and theoretical simulations to assist in the interpretation are discussed in detail. Different model systems are presented such as the different bulk phases of ice and various adsorbed monolayer structures on metal surfaces. PMID:27244473

  6. Magnetic soft x-ray microscopy-imaging fast spin dynamics inmagnetic nanostructures

    SciTech Connect

    Fischer, Peter; Kim, Dong-Hyun; Mesler, Brooke L.; Chao, Weilun; Sakdinawat, Anne E.; Anderson, Erik H.

    2007-06-01

    Magnetic soft X-ray microscopy combines 15nm spatial resolution with 70ps time resolution and elemental sensitivity. Fresnel zone plates are used as X-ray optics and X-ray magnetic circular dichroism serves as magnetic contrast mechanism. Thus scientifically interesting and technologically relevant low dimensional nanomagnetic systems can be imaged at fundamental length and ultrafast time scales in a unique way. Studies include magnetization reversal in magnetic multilayers, nanopatterned systems, vortex dynamics in nanoelements and spin current induced phenomena.

  7. Searching Ultimate Nanometrology for AlOx Thickness in Magnetic Tunnel Junction by Analytical Electron Microscopy and X-ray Reflectometry

    NASA Astrophysics Data System (ADS)

    Song, Se Ahn; Hirano, Tatsumi; Park, Jong Bong; Kaji, Kazutoshi; Kim, Ki Hong; Terada, Shohei

    2005-10-01

    Practical analyses of the structures of ultrathin multilayers in tunneling magneto resistance (TMR) and Magnetic Random Access Memory (MRAM) devices have been a challenging task because layers are very thin, just 1-2 nm thick. Particularly, the thinness ([similar]1 nm) and chemical properties of the AlOx barrier layer are critical to its magnetic tunneling property. We focused on evaluating the current TEM analytical methods by measuring the thickness and composition of an AlOx layer using several TEM instruments, that is, a round robin test, and cross-checked the thickness results with an X-ray reflectometry (XRR) method. The thickness measured by using HRTEM, HAADF-STEM, and zero-loss images was 1.1 nm, which agreed with the results from the XRR method. On the other hand, TEM-EELS measurements showed 1.8 nm for an oxygen 2D-EELS image and 3.0 nm for an oxygen spatially resolved EELS image, whereas the STEM-EDS line profile showed 2.5 nm in thickness. However, after improving the TEM-EELS measurements by acquiring time-resolved images, the measured thickness of the AlOx layer was improved from 1.8 nm to 1.4 nm for the oxygen 2D-EELS image and from 3.0 nm to 2.0 nm for the spatially resolved EELS image, respectively. Also the observed thickness from the EDS line profile was improved to 1.4 nm after more careful optimization of the experimental parameters. We found that EELS and EDS of one-dimensional line scans or two-dimensional elemental mapping gave a larger AlOx thickness even though much care was taken. The reasons for larger measured values can be found from several factors such as sample drift, beam damage, probe size, beam delocalization, and multiple scattering for the EDS images, and chromatic aberration, diffraction limit due to the aperture, delocalization, alignment between layered direction in samples, and energy dispersion direction in the EELS instrument for EELS images. In the case of STEM-EDS mapping with focused nanoprobes, it is always necessary

  8. Probing Transient Electron Dynamics Using Ultrafast X Rays

    NASA Astrophysics Data System (ADS)

    Bucksbaum, Philip

    2016-05-01

    Linear x-ray absorption in atoms or molecules creates highly excited multi-electron quantum systems, which relax rapidly by fluorescence or Auger emission. These relaxation rates are usually less than a few femtoseconds in duration, and so they can reveal transient elecronic states in molecules as they undergo photo-induced transformations. I will show recent results from femtosecond x-ray experiments that display this phenomenon. There are efforts underway to push the temporal resolving power of ultrafast x-ray pulses into the attosecond regime, using stronger fields to initiate nonlinear absorption processes such as transient stimulated electronic Raman scattering. I will discuss current progress and future prospects for research in this area. This research is supported through Stanford PULSE Institute, SLAC National Accelerator Lab by the U.S. Department of Energy, Office of Basic Energy Sciences, Atomic, Molecular, and Optical Science Program.

  9. Optical Shaping of X-Ray Free-Electron Lasers.

    PubMed

    Marinelli, A; Coffee, R; Vetter, S; Hering, P; West, G N; Gilevich, S; Lutman, A A; Li, S; Maxwell, T; Galayda, J; Fry, A; Huang, Z

    2016-06-24

    In this Letter we report the experimental demonstration of a new temporal shaping technique for x-ray free-electron lasers (FELs). This technique is based on the use of a spectrally shaped infrared (IR) laser and allows optical control of the x-ray generation process. By accurately manipulating the spectral amplitude and phase of the IR laser, we can selectively modify the electron bunch longitudinal emittance thus controlling the duration of the resulting x-ray pulse down to the femtosecond time scale. Unlike other methods currently in use, optical shaping is directly applicable to the next generation of high-average power x-ray FELs such as the Linac Coherent Light Source-II or the European X-FEL, and it enables pulse shaping of FELs at the highest repetition rates. Furthermore, this laser-shaping technique paves the way for flexible tailoring of complex multicolor FEL pulse patterns required for nonlinear multidimensional x-ray spectroscopy as well as novel multicolor diffraction imaging schemes. PMID:27391728

  10. Optical Shaping of X-Ray Free-Electron Lasers

    NASA Astrophysics Data System (ADS)

    Marinelli, A.; Coffee, R.; Vetter, S.; Hering, P.; West, G. N.; Gilevich, S.; Lutman, A. A.; Li, S.; Maxwell, T.; Galayda, J.; Fry, A.; Huang, Z.

    2016-06-01

    In this Letter we report the experimental demonstration of a new temporal shaping technique for x-ray free-electron lasers (FELs). This technique is based on the use of a spectrally shaped infrared (IR) laser and allows optical control of the x-ray generation process. By accurately manipulating the spectral amplitude and phase of the IR laser, we can selectively modify the electron bunch longitudinal emittance thus controlling the duration of the resulting x-ray pulse down to the femtosecond time scale. Unlike other methods currently in use, optical shaping is directly applicable to the next generation of high-average power x-ray FELs such as the Linac Coherent Light Source-II or the European X-FEL, and it enables pulse shaping of FELs at the highest repetition rates. Furthermore, this laser-shaping technique paves the way for flexible tailoring of complex multicolor FEL pulse patterns required for nonlinear multidimensional x-ray spectroscopy as well as novel multicolor diffraction imaging schemes.