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Sample records for site-specific photoelectron diffraction

  1. Oxygen as a site specific structural probe in neutron diffraction

    SciTech Connect

    Neuefeind, Joerg C; Simonson, J Michael {Mike}; Salmon, Phil; Zeidler, Anita; Fischer, Henry E; Rauch, Helmut; Markland, Thomas; Lemmel, Hartmut

    2011-01-01

    Oxygen is a ubiquitous element, playing an essential role in most scientific and technological disciplines, and is often incorporated within a structurally disordered material where examples include molten silicates in planetary science, glasses used for lasers and optical communication, and water in biological processes. Establishing the structure of a liquid or glassy oxide and thereby its relation to the functional properties of a material is not, however, a trivial task owing to the complexity associated with atomic disorder. Here we approach this challenge by measuring the bound coherent neutron scattering lengths of the oxygen isotopes with the sensitive technique of neutron interferometry. We find that there is a small but finite contrast of 0.204(6) fm between the scattering lengths of the isotope 18O and oxygen of natural isotopic abundance natO, contrary to tables of recommended values. This has enabled us to investigate the structure of both light and heavy water by exploiting, for the first time, the method of oxygen isotope substitution in neutron diffraction, thus circumventing many of the significant problems associated with more traditional methods in which hydrogen is substituted by deuterium. We find a difference of ~0.5% between the O-H and O-D intra-molecular bond distances which is much smaller than recent estimates based on diffraction data and is found to be in excellent agreement with path integral molecular dynamics simulations made with a flexible polarisable water model. Our results demonstrate the potential for using oxygen isotope substitution as a powerful and effective site specific probe in a plethora of materials, of pertinence as instrumentation at next generation neutron sources comes online

  2. Photoelectron diffraction and holography: Some new directions

    SciTech Connect

    Fadley, C.S. |

    1993-08-01

    Photoelectron diffraction has by now become a versatile and powerful technique for studying surface structures, with special capabilities for resolving chemical and magnetic states of atoms and deriving direct structural information from both forward scattering along bond directions and back-scattering path length differences. Further fitting experiment to theory can lead to structural accuracies in the {plus_minus}0.03 ){Angstrom} range. Holographic inversions of such diffraction data also show considerable promise for deriving local three-dimensional structures around a given emitter with accuracies of {plus_minus}0.2--0.3 {Angstrom}. Resolving the photoelectron spin in some way and using circularly polarized radiation for excitation provide added dimensions for the study of magnetic systems and chiral experimental geometries. Synchrotron radiation with the highest brightness and energy resolution, as well as variable polarization, is crucial to the full exploitation of these techniques.

  3. Photoelectron diffraction and holography: Present status and future prospects

    SciTech Connect

    Fadley, C.S. |; Thevuthasan, S.; Kaduwela, A.P.

    1993-07-01

    Photoelectron diffraction and photoelectron holography, a newly developed variant of it, can provide a rich range of information concerning surface structure. These methods are sensitive to atomic type, chemical state, and spin state. The theoretical prediction of diffraction patterns is also well developed at both the single scattering and multiple scattering levels, and quantitative fits of experiment to theory can lead to structures with accuracies in the {plus_minus}0.03 {Angstrom} range. Direct structural information can also be derived from forward scattering in scanned-angle measurements at higher energies, path length differences contained in scanned-energy data at lower energies, and holographic inversions of data sets spanning some region in angle and energy space. Diffraction can also affect average photoelectron emission depths. Circular dichroism in core-level emission can be fruitfully interpreted in terms of photoelectron diffraction theory, as can measurements with spin-resolved core-spectra, and studies of surface magnetic structures and phase transitions should be possible with these methods. Synchrotron radiation is a key element of fully utilizing these techniques.

  4. Surface structure determination of black phosphorus using photoelectron diffraction

    NASA Astrophysics Data System (ADS)

    de Lima, Luis Henrique; Barreto, Lucas; Landers, Richard; de Siervo, Abner

    2016-01-01

    The atomic structure of single-crystalline black phosphorus is studied using high-resolution synchrotron-based photoelectron diffraction (XPD). The results show that the topmost phosphorene layer in the black phosphorus is slightly displaced compared to the bulk structure and presents a small contraction in the direction perpendicular to the surface. Furthermore, the XPD results show the presence of a small buckling among the surface atoms, in agreement with previously reported scanning tunneling microscopy results. The contraction of the surface layer added to the presence of the buckling indicates a uniformity in the size of the s p3 bonds between P atoms at the surface.

  5. Photoelectron diffraction of magnetic ultrathin films: Fe/Cu(001)

    SciTech Connect

    Tobin, J.G. ); Wagner, M.K. . Dept. of Chemistry); Guo, X.Q.; Tong, S.Y. . Dept. of Physics)

    1991-01-03

    The preliminary results of an ongoing investigation of Fe/Cu(001) are presented here. Energy dependent photoelectron diffraction, including the spin-dependent variant using the multiplet split Fe3s state, is being used to investigate the nanoscale structures formed by near-monolayer deposits of Fe onto Cu(001). Core-level photoemission from the Fe3p and Fe3s states has been generated using synchrotron radiation as the tunable excitation source. Tentatively, a comparison of the experimental Fe3p cross section measurements with multiple scattering calculations indicates that the Fe is in a fourfold hollow site with a spacing of 3.6{Angstrom} between it and the atom directly beneath it, in the third layer. This is consistent with an FCC structure. The possibility of utilizing spin-dependent photoelectron diffraction to investigate magnetic ultrathin films will be demonstrated, using our preliminary spectra of the multiplet-split Fe3s os near-monolayer Fe/Cu(001). 18 refs., 10 figs.

  6. The interfacial and surface properties of thin Fe and Gd films grown on W(110) as studied by scanning tunneling microscopy, site-resolved photoelectron diffraction, and spin polarized photoelectron diffraction

    SciTech Connect

    Tober, E.D.

    1997-06-01

    Combined scanning tunneling microscopy (STM) and low energy electron diffraction (LEED) measurements from Gd films grown on W(110) prepared with and without annealing have been used to provide a detailed picture of the growth of such films, permitting a quantitative structural explanation for previously-measured magnetic properties and the identification of a new two-dimensional structure for the first monolayer. The analysis of the film roughness of room-temperature-grown films as a function of coverage and lateral length scale reveals that the growing Gd surface follows scaling laws for a self-affine surface. Annealing these as-deposited films at elevated temperatures is found to drastically alter the morphology of the films, as seen by both STM and LEED. Nanometer-scale islands of relatively well-defined size and shape are observed under certain conditions. Finally, the first monolayer of Gd is observed to form a (7x14) superstructure with pseudo-(7x7) symmetry that is consistent with a minimally-distorted hexagonal two-dimensional Gd(0001) film. Furthermore, a new beamline and photoelectron spectrometer/diffractometer at the Advanced Light Source have been used to obtain full-solid-angle and site-specific photoelectron diffraction (PD) data from interface W atoms just beneath (1x1) Fe and (7x14) Gd monolayers on W(110) by utilizing the core level shift in the W 4f{sub 7/2} spectrum. A comparison of experiment with multiple scattering calculations permits determining the Fe adsorption site and the relative interlayer spacing to the first and second W layers. These Fe results are also compared to those from the very different Gd overlayer and from the clean W(110) surface. Such interface PD measurements show considerable promise for future studies. Finally, the rare-earth ferromagnetic system of Gd(0001) has been examined through the use of spin polarized photoelectron diffraction from the Gd 4s and 5s photoelectron multiplets.

  7. Beyond hard x-ray photoelectron spectroscopy: Simultaneous combination with x-ray diffraction

    SciTech Connect

    Rubio-Zuazo, Juan; Castro, German R.

    2013-05-15

    Hard x-ray photoelectron spectroscopy (HAXPES) is a powerful and novel emerging technique for the nondestructive determination of electronic properties and chemical composition of bulk, buried interfaces and surfaces. It benefits from the exceptionally large escape depth of high kinetic energy photoelectrons, increasing the information depth up to several tens of nanometers. Complementing HAXPES with an atomic structure sensitive technique (such as x-ray diffraction) opens a new research field with major applications for materials science. At SpLine, the Spanish CRG beamline at the European Synchrotron Radiation Facility, we have developed a novel experimental set-up that combines HAXPES and x-ray diffraction (x-ray reflectivity, surface x-ray diffraction, grazing incidence x-ray diffraction, and reciprocal space maps). Both techniques can be operated simultaneously on the same sample and using the same excitation source. The set-up includes a robust 2S + 3D diffractometer hosting a ultrahigh vacuum chamber equipped with a unique photoelectron spectrometer (few eV < electron kinetic energy < 15 keV), x-ray tube (Mg/Ti), 15 keV electron gun, and auxiliary standard surface facilities (molecular beam epitaxy evaporator, ion gun, low energy electron diffraction, sample heating/cooling system, leak valves, load-lock sample transfer, etc.). This end-station offers the unique possibility of performing simultaneous HAXPES + x-ray diffraction studies. In the present work, we describe the experimental set-up together with two experimental examples that emphasize its outstanding capabilities: (i) nondestructive characterization of the Si/Ge and HfO{sub 2}/SiO{sub 2} interfaces on Ge-based CMOS devices, and (ii) strain study on La{sub 0.7}Ca{sub 0.3}MnO{sub 3} ultrathin films grown on SrTiO{sub 3}(001) substrate.

  8. Photoelectron diffraction from laser-aligned molecules with X-ray free-electron laser pulses

    PubMed Central

    Nakajima, Kyo; Teramoto, Takahiro; Akagi, Hiroshi; Fujikawa, Takashi; Majima, Takuya; Minemoto, Shinichirou; Ogawa, Kanade; Sakai, Hirofumi; Togashi, Tadashi; Tono, Kensuke; Tsuru, Shota; Wada, Ken; Yabashi, Makina; Yagishita, Akira

    2015-01-01

    We report on the measurement of deep inner-shell 2p X-ray photoelectron diffraction (XPD) patterns from laser-aligned I2 molecules using X-ray free-electron laser (XFEL) pulses. The XPD patterns of the I2 molecules, aligned parallel to the polarization vector of the XFEL, were well matched with our theoretical calculations. Further, we propose a criterion for applying our molecular-structure-determination methodology to the experimental XPD data. In turn, we have demonstrated that this approach is a significant step toward the time-resolved imaging of molecular structures. PMID:26369428

  9. Scanned-energy mode photoelectron diffraction measurements at beamline 7.0.1

    SciTech Connect

    Toomes, R.; Booth, N.A.; Woodruff, D.P.

    1997-04-01

    This report covers the results of the authors first experimental run, in May 1996, conducted to explore the advantages offered by the high spectral resolution available at the SpectroMicroscopy Facility on beam line 7.0 to conduct scanned-energy mode photoelectron diffraction (PhD). This technique is now a well-established method for the determination of local structure of atomic and molecular adsorbates on well-characterised surfaces. The directly-emitted component of an adsorbate core-level photoelectron wavefield interferes coherently with components of the same wavefield elastically scattered by surrounding atoms, leading to a modulation in the photoemission intensity as a function of kinetic energy in any specific emission direction. A series of such PhD modulation spectra, each typically covering energies from 50-500 eV, for a series of different emission directions, provides the basis for a quantitative structure determination of the emitter-scatterer geometry. Within the last years the authors have developed an integrated approach to extract the structural information from these photoelectron diffraction (PhD) spectra in a quantitative way. A direct data inversion technique (the so-called Projection method) provides a first-order estimate of the local adsorbate geometry in the form of an `image` of the scatterer atoms which are nearest neighbours to the emitter. This information is then used as a starting model for optimisation of the structural parameters by comparing the experimental PhD spectra with the results of multiple scattering simulations using a code developed by Fritzsche. The optimisation uses an automated trial-and-error procedure by minimising a reliability factor which provides an objective measure of the quality of agreement between experiment and theory. The authors have successfully applied this approach to the structure determination of about 30 adsorption systems.

  10. Interfacial atomic site characterization by photoelectron diffraction for 4H-AlN/4H-SiC(11\\bar{2}0) heterojunction

    NASA Astrophysics Data System (ADS)

    Maejima, Naoyuki; Horita, Masahiro; Matsui, Hirosuke; Matsushita, Tomohiro; Daimon, Hiroshi; Matsui, Fumihiko

    2016-08-01

    The interfacial atomic structure of an AlN thin film on a nonpolar 4H-SiC(11\\bar{2}0) substrate grown by atomic Al and N plasma deposition was studied by photoelectron diffraction and spectroscopy. The epitaxial growth of the thin film was confirmed by the comparison of element-specific photoelectron intensity angular distributions (PIADs). Depth profiles were analyzed by angle-resolved constant-final-state-mode X-ray photoelectron spectroscopy (AR-XPS). No polar angular dependence was observed in Al 2p spectra, while an additional intermixing component was found in interface-sensitive N 1s spectra. The site-specific N 1s PIADs for the AlN film and an intermixing component were derived from two N 1s PIADs with different binding energies. We attributed the intermixing component to SiN interfacial layer sites. In order to prevent SiN growth at the interface, we deposited Al on the SiC(11\\bar{2}0) substrate prior to the AlN growth. A significant reduction in the amount of intermixing components at the AlN/SiC interface was confirmed by AR-XPS.

  11. Photoelectron diffraction k-space volumes of the c(2x2) Mn/Ni(100) structure

    SciTech Connect

    Banerjee, S.; Denlinger, J.; Chen, X.

    1997-04-01

    Traditionally, x-ray photoelectron diffraction (XPD) studies have either been done by scanning the diffraction angle for fixed kinetic energy (ADPD), or scanning the kinetic energy at fixed exit angle (EDPD). Both of these methods collect subsets of the full diffraction pattern, or volume, which is the intensity of photoemission as a function of momentum direction and magnitude. With the high density available at the Spectromicroscopy Facility (BL 7.0) {open_quotes}ultraESCA{close_quotes} station, the authors are able to completely characterize the photoelectron diffraction patterns of surface structures, up to several hundred electron volts kinetic energy. This large diffraction `volume` can then be analyzed in many ways. The k-space volume contains as a subset the energy dependent photoelectron diffraction spectra along all emission angles. It also contains individual, hemispherical, diffraction patterns at specific kinetic energies. Other `cuts` through the data set are also possible, revealing new ways of viewing photoelectron diffraction data, and potentially new information about the surface structure being studied. In this article the authors report a brief summary of a structural study being done on the c(2x2) Mn/Ni(100) surface alloy. This system is interesting for both structural and magnetic reasons. Magnetically, the Mn/Ni(100) surface alloy exhibits parallel coupling of the Mn and Ni moments, which is opposite to the reported coupling for the bulk, disordered, alloy. Structurally, the Mn atoms are believed to lie well above the surface plane.

  12. Full-solid-angle photoelectron diffraction from bulk and surface atoms of clean W(110)

    SciTech Connect

    Ynzunza, R. X.; Tober, E. D.; Palomares, F. J.; Wang, Z.; Daimon, H.; Chen, Y.; Hussain, Z.; Van Hove, M. A.; Fadley, C. S.

    1997-04-01

    The authors have studied the atomic structure of the clean W(110) surface by means of site-resolved scanned-angle W4f{sub 7/2} photoelectron diffraction (PD) data obtained over nearly the full 2{pi} solid angle above the surface. Prior to the availability of high-brightness sources such as the Advanced Light Source, such large high-resolution data sets were prohibitively time consuming to obtain. The well characterized W(110) system was used as a reference case to check the accuracy of structure determinations from such scanned-angle data via R-factor comparisons of experiment with theoretical multiple scattering calculations. The photoelectron kinetic energy of {approximately}40 eV used was also lower than in many prior PD studies, providing further challenges to theory. The influence of various non-structural theoretical input parameters (e.g., scattering phase shifts, electron inelastic attenuation length, and inner potential) was thus also assessed. A final optimized structure is presented, together with comments on the future applications of this method.

  13. Uracil on Cu(110): A quantitative structure determination by energy-scanned photoelectron diffraction

    NASA Astrophysics Data System (ADS)

    Duncan, D. A.; Unterberger, W.; Kreikemeyer-Lorenzo, D.; Woodruff, D. P.

    2011-07-01

    The local adsorption site of the nucleobase uracil on Cu(110) has been determined quantitatively by energy-scanned photoelectron diffraction (PhD). Qualitative inspection of the O 1s and N 1s soft x-ray photoelectron spectra, PhD modulation spectra, and O K-edge near-edge x-ray adsorption fine structure indicate that uracil bonds to the surface through its nitrogen and oxygen constituent atoms, each in near atop sites, with the molecular plane essentially perpendicular to surface and aligned along the close packed [1overline 1 0] azimuth. Multiple scattering simulations of the PhD spectra confirm and refine this geometry. The Cu-N bondlength is 1.96 ± 0.04 Å, while the Cu-O bondlengths of the two inequivalent O atoms are 1.93 ± 0.04 Å and 1.96 ± 0.04 Å, respectively. The molecule is twisted out of the [1overline 1 0]direction by 11 ± 5°.

  14. Photoelectron diffraction studies of Cu on Pd(111) random surface alloys

    SciTech Connect

    Siervo, A. de; Landers, R.; Soares, E. A.; Kleiman, G.G.

    2005-03-15

    The study of surface alloys is motivated by their use in many applications of different segments of industry, such as in the search for new catalysts and sensors, in surface protection against corrosion, in lowering friction, and in testing electronic devices. An important aspect of surface alloys studies is that of the precise quantification of segregation and diffusion processes as well as the determination of surface structure. In this paper we report a combined low-energy electron diffraction and photoelectron diffraction (PED) (using synchrotron radiation) study of surface alloy formation when Cu ultrathin films are evaporated onto Pd(111) single-crystal surfaces. We present results for two different coverages (1 and 3 ML) and three annealing temperatures (300, 600, and 800 K). For these preparation conditions, a random alloy phase with different concentrations seems to form in the first few layers. Through the analysis of PED data performed using a multiple scattering formalism and the average T-matrix approximation it was possible to determine the atomic structure and the atomic concentration of the first three layers.

  15. Diffraction and holography with photoelectrons and Auger electrons: Some new directions

    SciTech Connect

    Fadley, C.S. Lawrence Berkeley Lab., CA )

    1992-06-01

    The current status of photoelectron and Auger-electron diffraction is reviewed, with emphasis on new directions of activity. The use of forward scattering in the study of adsorbed molecules, epitaxial overlayers, and clean surfaces is one of the most developed applications, and one that will become more powerful as higher energy resolution and perhaps spin analysis are used to resolve emitters on the basis of chemical state, position at a surface, or magnetic state. The use of larger data sets spanning a considerable fraction of the solid angle above a surface will also much enhance the structural information available, for example, in the growth of epitaxial layers or nanostructures on surfaces. Detailed fitting of experimental data to theoretical calculations based upon either single scattering or multiple scattering should also provide more rich structural information, including such parameters as substrate interlayer relaxation. Surface phase transitions in which near-surface layers become highly disordered can also be studied, with results that are complementary to those from such techniques as low energy electron diffraction and medium energy ion scattering. Short-range magnetic order also can be probed by somehow resolving the spin of the outgoing electrons, e.g. by using multiplet-split core levels.

  16. Normal emission photoelectron diffraction: a new technique for determining surface structure

    SciTech Connect

    Kevan, S.D.

    1980-05-01

    One technique, photoelectron diffraction (PhD) is characterized. It has some promise in surmounting some of the problems of LEED. In PhD, the differential (angle-resolved) photoemission cross-section of a core level localized on an adsorbate atom is measured as a function of some final state parameter. The photoemission final state consists of two components, one of which propagates directly to the detector and another which scatters off the surface and then propagates to the detector. These are added coherently, and interference between the two manifests itself as cross-section oscillations which are sensitive to the local structure around the absorbing atom. We have shown that PhD deals effectively with two- and probably also three-dimensionally disordered systems. Its non-damaging and localized, atom-specific nature gives PhD a good deal of promise in dealing with molecular overlayer systems. It is concluded that while PhD will never replace LEED, it may provide useful, complementary and possibly also more accurate surface structural information.

  17. Surface structure determination of Pd on W(100) using X-ray photoelectron diffraction

    NASA Astrophysics Data System (ADS)

    Lussani, F. C.; de Siervo, A.; de Figueiredo, J. J. S.; Pancotti, A.; Landers, R.

    2011-11-01

    Ferromagnetic ordering in non-ferromagnetic transition metals induced by structural effects such as lattice expansion and stacking faults have been predicted by several theoretical studies. Different surfaces such as Nb(100), W(100) and C(0001) have been suggested as potential templates which could drive a Pd ultrathin film to a stable ferromagnetic state, depending on growth packing, film thickness and lateral lattice parameter. In this work we present an X-ray photoelectron diffraction (XPD) study of sub-monolayer to a few layers of Pd grown on W(100) and its surface structure determination. XPD patterns of Pd 3d and W 4f peaks were measured using synchrotron radiation with photon energy of 1810 eV provided by the SXS beamline at the Brazilian Synchrotron Light Laboratory. Our results indicate that the first few monolayers of Pd grow on W(100) with bcc packing and lateral lattice parameter dramatically changed in comparison with the Pd(fcc) bulk values. Based on these results we also present a discussion on the magnetic properties of this system derived from spin-polarized DFT calculation.

  18. Characterizing Edge and Stacking Structures of Exfoliated Graphene by Photoelectron Diffraction

    NASA Astrophysics Data System (ADS)

    Matsui, Fumihiko; Ishii, Ryo; Matsuda, Hiroyuki; Morita, Makoto; Kitagawa, Satoshi; Matsushita, Tomohiro; Koh, Shinji; Daimon, Hiroshi

    2013-11-01

    The two-dimensional C 1s photoelectron intensity angular distributions (PIADs) and spectra of exfoliated graphene flakes and crystalline graphite were measured using a focused soft X-ray beam. Suitable graphene samples were selected by thickness characterization using Raman spectromicroscopy after transferring mechanically exfoliated graphene flakes onto a 90-nm-thick SiO2 film. In every PIAD, a Kagomé interference pattern was observed, particularly clearly in the monolayer graphene PIAD. Its origin is the overlap of the diffraction rings formed by an in-plane C-C bond honeycomb lattice. Thus, the crystal orientation of each sample can be determined. In the case of bilayer graphene, PIAD was threefold-symmetric, while those of monolayer graphene and crystalline graphite were sixfold-symmetric. This is due to the stacking structure of bilayer graphene. From comparisons with the multiple scattering PIAD simulation results, the way of layer stacking as well as the termination types in the edge regions of bilayer graphene flakes were determined. Furthermore, two different C 1s core levels corresponding to the top and bottom layers of bilayer graphene were identified. A chemical shift to a higher binding energy by 0.25 eV for the bottom layer was attributed to interfacial interactions.

  19. Fourier transform photoelectron diffraction and its application to molecular orbitals and surface structure

    SciTech Connect

    Zhou, Xin

    1998-11-30

    Photoemission intensities from the molecular orbitals of c(2x2)CO/Pt(111) over a wide photon energy range were measured and analyzed by the same methods developed for structural studies using core levels. The 4{sigma} orbital center of gravity is found to be concentrated between the C and O atoms, while that of the 5{sigma} orbital lies between the C atom and the Pt surface. The C 1s photoelectron diffraction was used to determine the adsorption geometry. The earlier ambiguity that multiple scattering is needed to correctly model a {chi} curve while single scattering is sufficient for understanding major peaks in the ARPEFS-FTS is clarified by studying the clean Ni(111) surface. In the normal emission case, several different combinations of scattering events have similar path length differences (PLDs), and can either cancel each other or enhance the corresponding FT peak. In the off-normal case the degeneracy is greatly reduced due to the lower degree of symmetry. In normal emission AR PEFS, up to third order multiple scattering is needed to describe fully both the {chi} curve and its FT spectrum. To improve the spectral resolution in the ARPEFS-FT analysis, several new spectral analysis methods are introduced. With both autocorrelation autoregression (ACAR) and autocorrelation eigenvector (ACE), we can produce a reliable power spectrum by following the order-closing procedure. The best spectra are usually obtained when the autocorrelation sequence is computed with lags up to half the data range. A simple way of determining surface adsorption sites is proposed as follows: First use a single scattering cluster for possible adsorption sites to construct the geometrical PLDs from the strong backscattering events; then compare these PLDs with those obtained from the ARPEFS-FT analysis of the experimental data. After the preferred adsorption site is determined, fine tune the interlayer distances according to the positional R-factor.

  20. Study of the oxidation of W(110) by full-solid-angle photoelectron diffraction with chemical state and time resolution

    SciTech Connect

    Ynzunza, R. X.; Palomares, F. J.; Tober, E. D.; Wang, Z.; Morais, J.; Denecke, R.; Daimon, H.; Chen, Y.; Hussain, Z; Liesengang, J.; Van Hove, M. A.; Fadley, C. S.

    1997-04-01

    The brightness of third-generation synchrotron radiation from beamline 9.3.2 at the Advanced Light Source has been combined with the high-intensities and energy resolutions possible with its advanced photoelectron spectrometer/diffractometer experimental station in order to study the time dependence of the oxidation of the W(110) surface. This has been done via chemical-state-resolved core-level photoelectron spectroscopy and diffraction. This system has been studied previously by other methods such as LEED and STM, but several questions remain as to the basic kinetics of oxidation and the precise adsorption structures involved. By studying the decay and growth with time of various peaks in the W 4f{sub 7/2} photoelectron spectra, it should be possible to draw quantitative conclusions concerning the reaction kinetics involved. The authors have also measured full-solid-angle photoelectron diffraction patterns for the two oxygen-induced W states, and these should permit fully defining the different structures involved in this oxidation process.

  1. Non-destructive assessment of the polarity of GaN nanowire ensembles using low-energy electron diffraction and x-ray photoelectron diffraction

    SciTech Connect

    Romanyuk, O. Jiříček, P.; Bartoš, I.; Fernández-Garrido, S.; Geelhaar, L.; Brandt, O.; Paskova, T.

    2015-01-12

    We investigate GaN nanowire ensembles spontaneously formed in plasma-assisted molecular beam epitaxy by non-destructive low-energy electron diffraction (LEED) and x-ray photoelectron diffraction (XPD). We show that GaN nanowire ensembles prepared on AlN-buffered 6H-SiC(0001{sup ¯}) substrates with well-defined N polarity exhibit similar LEED intensity-voltage curves and angular distribution of photo-emitted electrons as N-polar free-standing GaN layers. Therefore, as in the case of GaN layers, LEED and XPD are found to be suitable techniques to assess the polarity of GaN nanowire ensembles on a macroscopic scale. The analysis of GaN nanowire ensembles prepared on bare Si(111) allows us to conclude that, on this non-polar substrate, the majority of nanowires is also N-polar.

  2. Site-specific photochemistry

    NASA Astrophysics Data System (ADS)

    Koplitz, Brent D.; Brum, Jeffrey L.; Deshmukh, Subhash; Xu, Xiaodong; Wang, Zhongrui; Yen, Yu-Fong

    1992-04-01

    We present results on `site-specific' H-atom production in photolysis experiments conducted under collisionless conditions. H and D atoms are used as labels to investigate the site(s) at which C-H (or C-D) bond cleavage occurs in a variety of haloalkane systems. Experiments using two photolysis lasers clearly indicate that photon absorption by an intermediate, presumably an alkyl radical, is important in many of the systems studied. The site(s) (e.g., (alpha) , (beta) , or (gamma) ) at which C-H (or C-D) bond cleavage occurs is dependent not only on the nature of the molecule, but also on the photolysis wavelength. As a diagnostic tool, H- and D-atom Doppler spectroscopy allows us to gain insight into the energetics associated with the various dissociation processes. Our overall aim is to gain a further understanding of the photolysis properties of a variety of simple molecules and their associated radicals.

  3. Structure of the c(2x2) Mn/Ni(001) surface alloy by quantitative photoelectron diffraction

    SciTech Connect

    Banerjee, S.; Denlinger, J.; Chen, X.

    1997-04-01

    Surface alloys are two-dimensional metallic systems that can have structures that are unique to the surface, and have no counterpart in the bulk binary phase diagram. A very unusual structure was reported for the Mn-Ni system, based on a quantitative LEED structure determination, which showed that the Mn atoms were displaced out of the surface by a substantial amount. This displacement was attributed to a large magnetic moment on the Mn atoms. The structure of the Mn-Ni surface alloy was proposed to be based on a bulk termination model. Magnetic measurements on the Mn-Ni surface alloys, however, showed conclusively that the magnetic structure of these surface alloys is completely different from the bulk alloy analogs. For example, bulk MnNi is an antiferromagnet, whereas the surface alloy is ferromagnetic. This suggests that the proposed structure based on bulk termination, may not be correct. X-ray Photoelectron Diffraction (XPD) techniques were used to investigate this structure, using both a comparison to multiple scattering calculations and photoelectron holography. In this article the authors present some of the results from the quantitative analysis of individual diffraction patterns by comparison to theory.

  4. Convergence and reliability of the Rehr-Albers formalism in multiple-scattering calculations of photoelectron diffraction

    SciTech Connect

    Chen, Y.; Garcia de Abajo, F.J.; Ynzunza, R.X.; Kaduwela, A.P.; Van Hove, M.A.; Fadley, C.S. |

    1998-11-01

    The Rehr-Albers (RA) separable Green{close_quote}s-function formalism, which is based on an expansion series, has been successful in speeding up multiple-scattering cluster calculations for photoelectron diffraction simulations, particularly in its second-order version. The performance of this formalism is explored here in terms of computational speed, convergence over orders of multiple scattering, over orders of approximation, and over cluster size, by comparison with exact cluster-based formalisms. It is found that the second-order RA approximation [characterized by (6{times}6) scattering matrices] is adequate for many situations, particularly if the initial state from which photoemission occurs is of {ital s} or {ital p} type. For the most general and quantitative applications, higher-order versions of RA may become necessary for {ital d} initial states [third-order, i.e., (10{times}10) matrices] and {ital f} initial states [fourth-order, i.e., (15{times}15) matrices]. However, the required RA order decreases as an electron wave proceeds along a multiple-scattering path, and this can be exploited, together with the selective and automated cutoff of weakly contributing matrix elements and paths, to yield computer time savings of at least an order of magnitude with no significant loss of accuracy. Cluster sizes of up to approximately 100 atoms should be sufficient for most problems that require about 5{percent} accuracy in diffracted intensities. Excellent sensitivity to structure is seen in comparisons of second-order theory with variable geometry to exact theory as a fictitious {open_quotes}experiment.{close_quotes} Our implementation of the Rehr-Albers formalism thus represents a versatile, quantitative, and efficient method for the accurate simulation of photoelectron diffraction. {copyright} {ital 1998} {ital The American Physical Society}

  5. Fraunhofer-like diffracted lateral photoelectron momentum distributions of H2+ in charge-resonance-enhanced ionization in strong laser fields

    NASA Astrophysics Data System (ADS)

    Xin, Lin; Qin, Han-Cheng; Wu, Wan-Yang; He, Feng

    2015-12-01

    For H2+ at the critical internuclear distance where the charge-resonance-enhanced ionization is most prominent, the lateral photoelectron momentum distribution presents the Fraunhofer-like diffraction pattern: a central disk surrounded by one or more rings. We study this phenomenon by simulating the time-dependent Schrödinger equation and unveil the mechanism: the stretched molecule constructs an interatomic Coulomb potential, which works as a circular aperture and diffracts the electron when it travels between two nuclei. This distinct lateral photoelectron momentum distribution offers another perspective to look into molecular structures.

  6. The structure of formate on TiO{sub 2}(110) by scanned-energy and scanned-angle photoelectron diffraction

    SciTech Connect

    Thevuthasan, S.; Kim, Y.J.; Herman, G.S.

    1997-04-01

    There is a considerable interest in understanding the interaction of small organic molecules with oxide surfaces. The chemistry of formate interactions with TiO{sub 2}(110) has been investigated by several groups, but there is little information on the structure of the adsorbate/surface complex. Recently the authors combined high-energy x-ray photoelectron diffraction (XPD) measurements at PNNL with low-energy scanned-angle and scanned-energy photoelectron diffraction measurements at the ALS to investigate the structure of the formate ion on TiO{sub 2}(110) in detail. The high-energy XPD results reveal that formate binds through the oxygens in a bidentate fashion to Ti cation rows along the [001] direction with an O-C-O bond angle of about 126{degrees}. Low-energy photoelectron diffraction data, which is briefly described below, was used to identify the specific bonding geometry, including the bond length between the Ti cation and the oxygen in the formate.

  7. Polarity of semipolar wurtzite crystals: X-ray photoelectron diffraction from GaN(101⁻1) and GaN(202⁻1) surfaces

    SciTech Connect

    Romanyuk, O. Jiříček, P.; Bartoš, I.; Paskova, T.

    2014-09-14

    Polarity of semipolar GaN(101⁻1) (101⁻1⁻) and GaN(202⁻1) (202⁻1⁻) surfaces was determined with X-ray photoelectron diffraction (XPD) using a standard MgKα source. The photoelectron emission from N 1s core level measured in the a-plane of the crystals shows significant differences for the two crystal orientations within the polar angle range of 80–100° from the (0001) normal. It was demonstrated that XPD polar plots recorded in the a-plane are similar for each polarity of the GaN(101⁻1) and GaN(202⁻1) crystals if referred to (0001) crystal axes. For polarity determinations of all important GaN(h0h⁻l) semipolar surfaces, the above given polar angle range is suitable.

  8. Following the molecular motion of near-resonant excited CO on Pt(111): A simulated x-ray photoelectron diffraction study based on molecular dynamics calculations

    PubMed Central

    Greif, Michael; Nagy, Tibor; Soloviov, Maksym; Castiglioni, Luca; Hengsberger, Matthias; Meuwly, Markus; Osterwalder, Jürg

    2015-01-01

    A THz-pump and x-ray-probe experiment is simulated where x-ray photoelectron diffraction (XPD) patterns record the coherent vibrational motion of carbon monoxide molecules adsorbed on a Pt(111) surface. Using molecular dynamics simulations, the excitation of frustrated wagging-type motion of the CO molecules by a few-cycle pulse of 2 THz radiation is calculated. From the atomic coordinates, the time-resolved XPD patterns of the C 1s core level photoelectrons are generated. Due to the direct structural information in these data provided by the forward scattering maximum along the carbon-oxygen direction, the sequence of these patterns represents the equivalent of a molecular movie. PMID:26798798

  9. X-ray photoelectron spectroscopy and diffraction investigation of a metal-oxide-semiconductor heterostructure: Pt/Gd2O3/Si(111)

    NASA Astrophysics Data System (ADS)

    Ferrah, D.; El Kazzi, M.; Niu, G.; Botella, C.; Penuelas, J.; Robach, Y.; Louahadj, L.; Bachelet, R.; Largeau, L.; Saint-Girons, G.; Liu, Q.; Vilquin, B.; Grenet, G.

    2015-04-01

    Platinum thin films deposited by physical vapor deposition (PVD) on Gd2O3/Si(111) templates are investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and X-ray photoelectron diffraction (XPD). Both XRD and XPD give clear evidence that Gd2O3 grows (111)-oriented and single-domain on Si(111) with mirror epitaxial relationship viz., [1bar10] Gd2O3(111)//[11bar0] Si(111). On Gd2O3/Si(111), Pt is partially crystallized with (111) orientation. There are two epitaxial domains and a slightly visible (111) fiber texture. The in-plane relationships of these Pt(111) domains with Gd2O3(111) are a direct one: [11bar0] Pt(111)//[11bar0] Gd2O3(111) and a mirror one: [1bar10] Pt(111)//[11bar0] Gd2O3(111). XPS reveals that Pt4f exhibits a metallic behavior even for small amounts of Pt but very small chemical shifts suggest that Pt environment is different at the interface with Gd2O3. These XPS chemical shifts have been correlated with features in XPD azimuth curves, which could be related with the existence of hexagonal α-PtO2(0001)layer.

  10. The effect of Sr and Bi on the Si(100) surface oxidation - Auger electron spectroscopy, low energy electron diffraction, and X-ray photoelectron spectroscopy study

    NASA Technical Reports Server (NTRS)

    Fan, W. C.; Mesarwi, A.; Ignatiev, A.

    1990-01-01

    The effect of Sr and Bi on the oxidation of the Si(100) surface has been studied by Auger electron spectroscopy, low electron diffraction, and X-ray photoelectron spectroscopy. A dramatic enhancement, by a factor of 10, of the Si oxidation has been observed for Si(100) with a Sr overlayer. The SR-enhanced Si oxidation has been studied as a function of O2 exposure and Sr coverage. In contrast to the oxidation promotion of Sr on Si, it has been also observed that a Bi overlayer on Si(100) reduced Si oxidation significantly. Sr adsorption on the Si(100) with a Bi overlayer enhances Si oxidation only at Sr coverage of greater than 0.3 ML.

  11. High-resolution electron-energy-loss spectroscopy and photoelectron-diffraction studies of the geometric structure of adsorbates on single-crystal metal surfaces

    SciTech Connect

    Rosenblatt, D.H.

    1982-11-01

    Two techniques which have made important contributions to the understanding of surface phenomena are high resolution electron energy loss spectroscopy (EELS) and photoelectron diffraction (PD). EELS is capable of directly measuring the vibrational modes of clean and adsorbate covered metal surfaces. In this work, the design, construction, and performance of a new EELS spectrometer are described. These results are discussed in terms of possible structures of the O-Cu(001) system. Recommendations for improvements in this EELS spectrometer and guidelines for future spectrometers are given. PD experiments provide accurate quantitative information about the geometry of atoms and molecules adsorbed on metal surfaces. The technique has advantages when used to study disordered overlayers, molecular overlayers, multiple site systems, and adsorbates which are weak electron scatterers. Four experiments were carried out which exploit these advantages.

  12. Investigation of the near-surface structures of polar InN films by chemical-state-discriminated hard X-ray photoelectron diffraction

    SciTech Connect

    Yang, A. L.; Yamashita, Y.; Kobata, M.; Yoshikawa, H.; Sakata, O.; Kobayashi, K.; Matsushita, T.; Pis, I.; Imura, M.; Yamaguchi, T.; Nanishi, Y.

    2013-01-21

    Near-surface structures of polar InN films were investigated by laboratory-based hard X-ray photoelectron diffraction (HXPD) with chemical-state-discrimination. HXPD patterns from In 3d{sub 5/2} and N 1s core levels of the In-polar and N-polar InN films were different from each other and compared with the simulation results using a multiple-scattering cluster model. It was found that the near-surface structure of the In-polar InN film was close to the ideal wurtzite structure. On the other hand, on the N-polar InN film, defects-rich surface was formed. In addition, the existence of the In-polar domains was observed in the HXPD patterns.

  13. Origin of diffraction fringes in two-dimensional photoelectron momentum distributions for single ionization of atoms in few-cycle intense laser pulses

    NASA Astrophysics Data System (ADS)

    Guo, Zhi-Jian; Chen, Zhang-Jin; Zhou, Xiao-Xin

    2014-04-01

    We use the strong field approximation with a time window function controlling the release time of electrons to study the intra-cycle and inter-cycle interferences in few-cycle intense laser pulses impinging on He. The diffraction fringes, i.e., the vertical stripe-like structure, observed in the experimental two-dimensional photoelectron momentum distributions of Gopal et al. (2009 Phys. Rev. Lett. 103 053001) have been attributed to the interplay of the intra- and inter-cycle interferences. The pure numerical calculations by solving the time-dependent Schrödinger equation are also performed and the results are compared with the experimental measurements directly. It has been found that the position of the stripe-like structure can be used to determine the duration of the laser pulses used in experiments.

  14. Characterization of an Yb:LuVO 4 single crystal using X-ray topography, high-resolution X-ray diffraction, and X-ray photoelectron spectroscopy

    NASA Astrophysics Data System (ADS)

    Paszkowicz, W.; Romanowski, P.; Bąk-Misiuk, J.; Wierzchowski, W.; Wieteska, K.; Graeff, W.; Iwanowski, R. J.; Heinonen, M. H.; Ermakova, O.; Dąbkowska, H.

    2011-10-01

    Knowledge on the defect and electronic structure allows for improved modeling of material properties. A short literature review has shown that the information on defect structure of rare earth orthovanadate single crystals is limited. In this paper, defect and electronic structure of a needle-shaped Yb:LuVO 4 single crystal grown by the slow cooling method have been studied by means of X-ray diffraction topography employing white synchrotron beam, high-resolution diffraction (HRD) and photoelectron spectroscopy (XPS) techniques. Topographic investigations show that the crystal is composed of two blocks disoriented by about 1.5° and separated by a narrow deformed region. Some contrasts observed within the crystal volume may be attributed to glide bands and sector boundaries. The contrasts appearing in the vicinity of the surface may be interpreted as due to the presence of small inclusions. The HRD study indicates, in particular, that among point defects, the vacancy type defects dominate and that the density of other defects is small in comparison. The XPS measurements enabled, despite highly insulating properties of the studied crystal, an analysis of its bulk electronic structure, including the main core-levels (O 1 s, V 2 p, Lu 4 f) as well as the valence band range.

  15. Atomic scale structure of the 5-fold surface of an AlPdMn quasicrystal: A quantitative X-Ray photoelectron diffraction analysis

    SciTech Connect

    Zheng, Jin-Cheng; Huan, C.H.A.; Wee, A.T.S.; Van Hove, M.A.; Fadley, C.S.; Shi, F.J.; Rotenberg, E.; Barman, S.R.; Paggel, J.J.; Horn, K.; Ebert, Ph.; Urban, K.

    2004-02-11

    The atomic scale structure of the 5-fold symmetric surface of an AlPdMn quasicrystal is investigated quantitatively by comparing x-ray photoelectron diffraction (XPD) simulations to experiment. The observed 5-fold symmetry of the diffraction patterns indicates that the surface is quasicrystalline with no hint of a reconstruction from the bulk structure. In analyzing the experimental data, many possible bulk terminations have been tested. Those few that fit best to the data have in common that they contain an Al-rich surface layer followed by a dense mixed Al/Pd/Mn layer. These best terminations, while not identical to each other, are suggested to form terraces coexisting on a real surface. Structural relaxations of the quasicrystal surface are also analyzed: mixing several best-fit terminations gives average best-fit interlayer spacing changes of Dd12 = -0.057 Angstrom, Dd24 = +0.159 Angstrom. These results are in good agreement with a prior structure determination by LEED on a sample that was prepared in a different manner.

  16. X-ray Photoelectron Diffraction (XPD) Study of the Growth of Cu on clean and O-precovered Ru(0001).

    NASA Astrophysics Data System (ADS)

    Ruebush, S. R.; Couch, R. E.; Fadley, C. S.; Thevuthasan, S.

    1996-03-01

    We have studied the growth of Cu on clean and O-precovered Ru(0001) for the first time with XPD, measuring experimental O 1s (E_kin=958 eV), Cu 2p3/2 (E_kin=554 eV), and Ru 3d (E_kin=1206eV) intensities over nearly the full 2π solid angle above the surface for Cu coverages from submonolayer up to many monolayers. We have analyzed our data using single and multiple scattering diffraction calculations. We have found a continuous Cu interlayer spacing from 1.84 Åat 1 ML to about 2.00 Åat 8 ML, with the bulk Cu spacing being 2.08 ÅWe have also studied the effect that a surfactant such as oxygen has on the growth of Cu. Our XPD studies show that all oxygen floats on the Cu surface. In addition, a preliminary analysis of our data suggests a tendency towards island growth for about 1-3 ML. We will compare our results with prior theoretical and experimental studies of this system.

  17. Site-specific magnetization reversal studies of magnetite

    SciTech Connect

    Cady, A.; Haskel, D.; Lang, J. C.; Islam, Z.; Srajer, G.; Ankudinov, A.; Subias, G.; Garcia, J.

    2006-04-01

    The mechanism of magnetization reversal in magnetite (Fe{sub 3}O{sub 4}) single crystals was studied using site-specific magnetic sensitive diffraction anomalous near-edge structure. By exploiting the angular dependence of the cross section, we are able to show that the mechanism of reversal involves a mixture of coherent rotation and domain formation. The results reveal additional details to that provided by XMCD measurements, which average over nonequivalent sites.

  18. Structural origin of Si-2p core-level shifts from Si(100)-c[4x2] surface: A spectral x-ray photoelectron diffraction study

    SciTech Connect

    Chen, X.; Tonner, B.P.; Denlinger, J.

    1997-04-01

    The authors have performed angle-resolved x-ray photoelectron diffraction (XPD) from a Si(100)-c(4x2) surface to study the structural origin of Si-2p core-level shifts. In the experiment, the highly resolved surface Si-2p core-level spectra were measured as a fine grid of hemisphere and photon energies, using the SpectroMicroscopy Facility {open_quotes}ultraESCA{close_quotes} instrument. By carefully decomposing the spectra into several surface peaks, the authors are able to obtain surface-atom resolved XPD patterns. Using a multiple scattering analysis, they derived a detailed atomic model for the Si(100)-c(4x2) surface. In this model, the asymmetric dimers were found tilted by 11.5 plus/minus 2.0 degrees with bond length of 2.32 plus/minus 0.05{angstrom}. By matching model XPD patterns to experiment, the authors can identify which atoms in the reconstructed surface are responsible for specific photoemission lines in the 2p spectrum.

  19. NORMAL LOAD BEARING BY SITE SPECIFIC CANISTER

    SciTech Connect

    NA

    2005-03-23

    The overall purpose of this calculation is to perform a preliminary analysis of the Site Specific Canister/Basket, subject to static gravity loads that include the self weight of the Canister Shell, the Basket, the Spent Nuclear Fuel, the Shield Plug and the related hardware, so that the loads are approximately known for sizing purposes. Based on these loads the stress levels in various components of the Site Specific Canister/Basket are evaluated.

  20. Oxidation of UO 2 fuel pellets in air at 503 and 543 K studied using X-ray photoelectron spectroscopy and X-ray diffraction

    NASA Astrophysics Data System (ADS)

    Tempest, P. A.; Tucker, P. M.; Tyler, J. W.

    1988-02-01

    An understanding of the low temperature oxidation behaviour of UO 2 pellets in air is important in the unlikely event of gas ingress to a fuel can during handling or storage. The main parameter of concern is the production time of U 3O 8 particulate as a function of temperature. Factors which affect the UO2 → U3O8 transformation have been investigated by sequentially oxidising UO 2 fuel pellets in air at 503 and 543 K and monitoring the growth of U 3O and U 3O 7 using X-ray photoelectron spectroscopy, X-ray diffraction and scanning electron microscopy. Initially oxidation proceeded at a linear rate by the inward diffusion of oxygen to form a complete layer of substoichiometric U 3O 7. This phase was tetragonal with a {c}/{a} ratio of 1.015, significantly less than the value of 1.03 measured on UO 2 powder when oxidised under identical conditions. This difference and the preferred orientation exhibited by surface grains were caused by growth stresses induced in the pellet surface. Both intergranular and transgranular cracking occurred and became nucleation sites for the growth of U 3O 8. The linear oxidation period associated with U 3O 7 growth was much shorter at 543 than at 503 K and U 3O 8 nucleated earlier. Spallation and the production of particulate were only observed during the formation of U 3O 8 when a 30% increase in volume arose from the U3O7 → U3O8 phase change.

  1. Thermodynamic basis of site-specific cooperativity.

    PubMed

    Di Cera, E

    1994-08-01

    Cooperative phenomena in biological macromolecules arise from the interaction of many distinct subsystems, such as structural domains or binding sites. Cooperative properties of the system as a whole, like protein folding or allosteric transitions, are subject to the restrictions imposed by thermodynamic stability. These restrictions, however, do not apply in the case of individual subsystems open to interactions with the rest of the macromolecule. The site-specific properties of such subsystems can be understood in general thermodynamic terms from those of a multicomponent system under particular conditions. The analogy provides a thermodynamic basis for site-specific cooperativity. PMID:8075382

  2. Site-Specific Infrared Probes of Proteins

    PubMed Central

    Ma, Jianqiang; Pazos, Ileana M.; Zhang, Wenkai; Culik, Robert M.; Gai, Feng

    2015-01-01

    Infrared spectroscopy has played an instrumental role in studying a wide variety of biological questions. However, in many cases it is impossible or difficult to rely on the intrinsic vibrational modes of biological molecules of interest, such as proteins, to reveal structural and/or environmental information in a site-specific manner. To overcome this limitation, many recent efforts have been dedicated to the development and application of various extrinsic vibrational probes that can be incorporated into biological molecules and used to site-specifically interrogate their structural and/or environmental properties. In this Review, we highlight some recent advancements of this rapidly growing research area. PMID:25580624

  3. DOE site-specific threat assessment

    SciTech Connect

    West, D.J.; Al-Ayat, R.A.; Judd, B.R.

    1985-07-12

    A facility manager faced with the challenges of protecting a nuclear facility against potential threats must consider the likelihood and consequences of such threats, know the capabilities of the facility safeguards and security systems, and make informed decisions about the cost-effectivness of safeguards and security upgrades. To help meet these challenges, the San Francisco Operations Office of the Department of Energy, in conjunction with the Lawrence Livermore Laboratory, has developed a site-specific threat assessment approach and a quantitative model to improve the quality and consistency of site-specific threat assessment and resultant security upgrade decisions at sensitive Department of Energy facilities. 5 figs.

  4. X-ray photoelectron diffraction study of thin Cu films grown on clean Ru(0001) and O-precovered Ru(0001)

    NASA Astrophysics Data System (ADS)

    Ruebush, S. D.; Couch, R. E.; Thevuthasan, S.; Fadley, C. S.

    1999-02-01

    We have studied the epitaxial growth modes and near-surface interlayer relaxation of thin Cu films on Ru(0001) using X-ray photoelectron diffraction (XPD), measuring experimental Cu 2p 3/2 ( Ekin=556 eV) and Ru 3d ( Ekin=1206 eV) intensities over one-third of the nearly full 2 π solid angle above the surface for Cu coverages from submonolayer up to 40 monolayers. Reference Cu 2p 3/2 data for a clean Cu(111) surface have also been obtained from Naumović et al. and in our laboratory. These data have been compared to single scattering cluster (SSC) and more accurate multiple scattering cluster (MSC) calculations via a sum of five R-factors to derive precise structural information. MSC calculations are found to give a more accurate description for layers of ≥4 ML thickness, and comparisons of experiment and theory are also improved by allowing more accurately for the effective degree of angular averaging involved. Calculations for thicker layers are also found to converge by ˜5 ML. Our analysis indicates that the first Cu layer grows pseudomorphically on Ru(0001), in agreement with prior studies. An R-factor analysis comparing MSC and SSC calculations to experimental results further indicates that the Cu-Ru interlayer spacing at 1 monolayer (ML) is about 2.15 Å, in excellent agreement with prior low-energy ion scattering (LEIS) and low-energy electron diffraction (LEED) experimental studies, as well as with prior linearized augmented plane-wave (LAPW) calculations. At higher coverages, comparison of our data to SSC and MSC calculations for various atomic clusters indicates that the short-range structure is fcc Cu(111)-like, but with significant interlayer contraction which persists up to ≥5 ML coverage. Prior STM work by Behm et al. has shown a series of misfit dislocation structures in the top layer of the Cu film at higher coverages from 2 to 4 ML. Our data indicate that these misfit dislocation structures thread to the Cu/Ru interface rather than occurring

  5. Nanoparticles for Site Specific Genome Editing

    NASA Astrophysics Data System (ADS)

    McNeer, Nicole Ali

    Triplex-forming peptide nucleic acids (PNAs) can be used to coordinate the recombination of short 50-60 by "donor DNA" fragments into genomic DNA, resulting in site-specific correction of genetic mutations or the introduction of advantageous genetic modifications. Site-specific gene editing in hematopoietic stem and progenitor cells (HSPCs) could result in treatment or cure of inherited disorders of the blood such as beta-thalassemia. Gene editing in HSPCs and differentiated T cells could help combat HIV/AIDs by modifying receptors, such as CCR5, necessary for R5-tropic HIV entry. However, translation of genome modification technologies to clinical practice is limited by challenges in intracellular delivery, especially in difficult-to-transfect hematolymphoid cells. In vivo gene editing could also provide novel treatment for systemic monogenic disorders such as cystic fibrosis, an autosomal recessive disorder caused by mutations in the cystic fibrosis transmembrane receptor. Here, we have engineered biodegradable nanoparticles to deliver oligonucleotides for site-specific genome editing of disease-relevant genes in human cells, with high efficiency, low toxicity, and editing of clinically relevant cell types. We designed nanoparticles to edit the human beta-globin and CCR5 genes in hematopoietic cells. We show that poly(lactic-co-glycolic acid) (PLGA) nanoparticles can delivery PNA and donor DNA for site-specific gene modification in human hematopoietic cells in vitro and in vivo in NOD-scid IL2rgammanull mice. Nanoparticles delivered by tail vein localized to hematopoietic compartments in the spleen and bone marrow of humanized mice, resulting in modification of the beta-globin and CCR5 genes. Modification frequencies ranged from 0.005 to 20% of cells depending on the organ and cell type, without detectable toxicity. This project developed highly versatile methods for delivery of therapeutics to hematolymphoid cells and hematopoietic stem cells, and will help to

  6. Transposon-specified site-specific recombination.

    PubMed Central

    Kitts, P; Symington, L; Burke, M; Reed, R; Sherratt, D

    1982-01-01

    Cointegrate DNA molecules containing two copies of a transposable element appear to be intermediates in the transposition process. These structures are resolved by site-specific recombination to yield the normal end products of transposition. The transposable element gamma delta (Tn1000) synthesizes a product interchangeable with the Tn1/3tnpR protein in promoting Tn1/3 site-specific recombination. These data support the hypothesis that cointegrates containing directly repeated copies of Tn1/3 are obligatory intermediates in interreplicon transposition of Tn1/3. In addition, we show here that the reaction is independent of the element-encoded tnpA gene product. Tn501, which specifies mercury resistance, also produces cointegrates as intermediates in interreplicon transposition. The appearance of Tn501-specified recombination activity that can act on these cointegrates requires growth of cells in the presence of Hg2+. Images PMID:6275390

  7. Site-Specific PEGylation of Therapeutic Proteins

    PubMed Central

    Dozier, Jonathan K.; Distefano, Mark D.

    2015-01-01

    The use of proteins as therapeutics has a long history and is becoming ever more common in modern medicine. While the number of protein-based drugs is growing every year, significant problems still remain with their use. Among these problems are rapid degradation and excretion from patients, thus requiring frequent dosing, which in turn increases the chances for an immunological response as well as increasing the cost of therapy. One of the main strategies to alleviate these problems is to link a polyethylene glycol (PEG) group to the protein of interest. This process, called PEGylation, has grown dramatically in recent years resulting in several approved drugs. Installing a single PEG chain at a defined site in a protein is challenging. Recently, there is has been considerable research into various methods for the site-specific PEGylation of proteins. This review seeks to summarize that work and provide background and context for how site-specific PEGylation is performed. After introducing the topic of site-specific PEGylation, recent developments using chemical methods are described. That is followed by a more extensive discussion of bioorthogonal reactions and enzymatic labeling. PMID:26516849

  8. Photoelectron Spectra

    ERIC Educational Resources Information Center

    Bock, Hans; Mollere, Phillip D.

    1974-01-01

    Presents an experimental approach to teaching molecular orbital models. Suggests utilizing photoelectron spectroscopy and molecular orbital theory as complementary approaches to teaching the qualitative concepts basic to molecular orbital theory. (SLH)

  9. Site-specific Auger electron spectra of ethyl trifluoroacelate molecules studied by magnetic bottle electron spectrometer

    NASA Astrophysics Data System (ADS)

    Iwayama, Hiroshi; Shigemasa, Eiji; Hikosaka, Yasumasa; Nakano, Motoyoshi; Ito, Kenji; Lablanquie, Pascal; Penet, Francis; Andric, Lidija; Selles, Patricia

    2012-11-01

    We performed multielectron coincidence measurements for inner-shell photoionizations of ethyl trifluoroacelate molecules (C4H5F3O2) using a magnetic bottle electron spectrometer. From a two dimensional coincidence map between a photoelectron and Auger electron for C 1s ionizations, we extracted site-specific Auger electron spectra for each carbon site and corresponding binding energy of doubly charged states.

  10. Site-Specific Carbon Isotopes in Organics

    NASA Astrophysics Data System (ADS)

    Piasecki, A.; Eiler, J. M.

    2012-12-01

    Natural organic molecules exhibit a wide range of internal site-specific isotope variation (i.e., molecules with same isotopic substitution type but different site). Such variations are generally unconstrained by bulk isotopic measurements. If known, site-specific variations might constrain temperatures of equilibrium, mechanisms of formation or consumption reactions, and possibly other details. For example, lipids can exhibit carbon isotope differences of up to 30‰ between adjacent carbon sites as a result of fractionations arising during decarboxylation of pyruvate and other steps in lipid biosynthesis(1). We present a method for site-specific carbon isotope analysis of propane, based on high-resolution, multi-collector gas source mass spectrometry, using a novel prototype instrument - the Thermo MAT 253 Ultra. This machine has an inlet system and electron bombardment ion source resembling those in conventional stable isotope gas source mass spectrometers, and the energy filter, magnet, and detector array resembling those in multi-collector ICPMS and TIMS. The detector array has 7 detector positions, 6 of which are movable, and each of which can collect ions with either a faraday cup (read through amplifiers ranging from 107-1012 ohms) or an SEM. High mass resolving power (up to 27,000, MRP = M/dM definition) is achieved through a narrow entrance slit, adjustable from 250 to 5 μm. Such resolution can cleanly separate isobaric interferences between isotopologues of organic molecules having the same cardinal mass (e.g., 13CH3 and 12CH2D). We use this technology to analyze the isotopologues and fragments of propane, and use such data to solve for the site-specific carbon isotope fractionation. By measuring isotopologues of both the one-carbon (13CH3) and the two-carbon (13C12CH4) fragment ion, we can solve for both bulk δ13C and the difference in δ13C between the terminal and central carbon position. We tested this method by analyzing mixtures between natural

  11. Savannah River Site's Site Specific Plan

    SciTech Connect

    Not Available

    1991-08-01

    This Site Specific Plan (SSP) has been prepared by the Savannah River Site (SRS) in order to show the Environmental Restoration and Waste Management activities that were identified during the preparation of the Department of Energy-Headquarters (DOE-HQ) Environmental Restoration and Waste Management Five-Year Plan (FYP) for FY 1992--1996. The SSP has been prepared in accordance with guidance received from DOE-HQ. DOE-SR is accountable to DOE-HQ for the implementation of this plan. The purpose of the SSP is to develop a baseline for policy, budget, and schedules for the DOE Environmental Restoration and Waste Management activities. The plan explains accomplishments since the Fiscal Year (FY) 1990 plan, demonstrates how present and future activities are prioritized, identifies currently funded activities and activities that are planned to be funded in the upcoming fiscal year, and describes future activities that SRS is considering.

  12. The Connectivity Between Site-Specific Life Cycle Impact Assessment and Site-Specific Weighting

    EPA Science Inventory

    The goal of many LCIAs is to come to a single score with all of the impacts from a wide variety of impact assessments weighted to form this single score. My past experiences with developing site-specific impact assessment methodologies and how this can change the valuation porti...

  13. Site-specific seismic hazard analyses

    NASA Astrophysics Data System (ADS)

    Montalva, Gonzalo Andres

    Current seismic hazard analyses are generally performed using probabilistic methods. When dealing with a specific site, the typical methodology involves using a ground motion prediction equation (GMPE) to estimate the rock outcrop ground motion and associated variability, then the ground motion is propagated to the ground surface by site response analysis. The site response process is inherently variable. Including this uncertainty in site response analyses without modifying the input ground motion uncertainty produces double counting of the uncertainty associated with site response. In this dissertation the total uncertainty is partitioned into its several contributing components, quantifying these components, and proposing methods to perform site-specific seismic hazard analyses without double counting uncertainties. Four random field models were developed, and an existing one was fitted to a different database. These models can be used to generate shear-wave velocity profiles for site response analyses. Two types of models are presented, using Gaussian random fields, and using Markov Chains. The first ones showed better performance, and among those a stationary Gaussian model (stationary on rho) showed the best performance, and it is the simplest among the five models. Three GMPE's were developed, one only from surface records, one from "at-depth" records, and a third one combining surface and "at-depth" records. The results show the iv same magnitude and distance scaling for the three equations. For stations that recorded a large number of records, total uncertainty was measured by the standard deviation of the observed minus predicted, and similarly for intra-event residuals. These statistics serve as lower bounds for site-specific seismic hazard analyses, note that these standard deviations are non-ergodic. The use of a GMPE capable of predicting bedrock and surface median ground motions, allows the partition of the components of the total uncertainty at the

  14. RESRAD. Site-Specific Residual Radioactivity

    SciTech Connect

    Yu, C.

    1989-06-01

    RESRAD is designed to derive site-specific guidelines for allowable residual concentrations of radionuclides in soil. A guideline is defined as a radionuclide concentration or a level of radiation or radioactivity that is acceptable if a site is to be used without radiological restrictions. Guidelines are expressed as (1) concentrations of residual radionuclides in soil, (2) concentrations of airborne radon decay products, (3) levels of external gamma radiation, (4) levels of radioactivity from surface contamination, and (5) concentrations of residual radionuclides in air and water. Soil is defined as unconsolidated earth material, including rubble and debris that may be present. The controlling principles of all guidelines are (1) the annual radiation dose received by a member of the critical population group from the residual radioactive material - predicted by a realistic but reasonably conservative analysis and averaged over a 50 year period - should not exceed 100 mrem/yr, and (2) doses should be kept as low as reasonably achievable. All significant exposure pathways for the critical population group are considered in deriving soil guidelines. These pathways include direct exposure to external radiation from the contaminated soil material; internal radiation from inhalation of airborne radionuclides; and internal radiation from ingestion of plant foods grown in the contaminated soil, meat and milk from livestock fed with contaminated fodder and water, drinking water from a contaminated well, and fish from a contaminated pond.

  15. Site-Specific, Climate-Friendly Farming

    NASA Astrophysics Data System (ADS)

    Brown, D. J.; Brooks, E. S.; Eitel, J.; Huggins, D. R.; Painter, K.; Rupp, R.; Smith, J. L.; Stockle, C.; Vierling, L. A.

    2011-12-01

    Of the four most important atmospheric greenhouse gasses (GHG) enriched through human activities, only nitrous oxide (N2O) emissions are due primarily to agriculture. However, reductions in the application of synthetic N fertilizers could have significant negative consequences for a growing world population given the crucial role that these fertilizers have played in cereal yield increases since WWII. Increasing N use efficiency (NUE) through precision management of agricultural N in space and time will therefore play a central role in the reduction of agricultural N2O emissions. Precision N management requires a greater understanding of the spatio-temporal variability of factors supporting N management decisions such as crop yield, water and N availability, utilization and losses. We present an overview of a large, collaborative, multi-disciplinary project designed to improve our basic understanding of nitrogen (N), carbon (C) and water (H2O) spatio-temporal dynamics for wheat-based cropping systems on complex landscapes, and develop management tools to optimize water- and nitrogen-use efficiency for these systems and landscapes. Major components of this project include: (a) cropping systems experiments addressing nitrogen application rate and seeding density for different landscape positions; (b) GHG flux experiments and monitoring; (c) soil microbial genetics and stable isotope analyses to elucidate biochemical pathways for N2O production; (d) proximal soil sensing for construction of detailed soil maps; (e) LiDAR and optical remote sensing for crop growth monitoring; (f) hydrologic experiments, monitoring, and modeling; (g) refining the CropSyst simulation model to estimate biophysical processes and GHG emissions under a variety of management and climatic scenarios; and (h) linking farm-scale enterprise budgets to simulation modeling in order to provide growers with economically viable site-specific climate-friendly farming guidance.

  16. X-ray photoelectron diffraction study of dopant effects in La{sub 0.7}X{sub 0.3}MnO{sub 3} (X = La, Sr, Ca, Ce) thin films

    SciTech Connect

    Raisch, C.; Glaser, M.; Chasse, T.; Langheinrich, C.; Chasse, A.; Werner, R.; Kleiner, R.; Koelle, D.

    2013-02-14

    We present and discuss element-specific x-ray photoelectron diffraction (XPD) patterns of La, Mn, O and the dopant ions Ca, Sr and Ce of various La{sub 0.7}X{sub 0.3}MnO (LXMO) films grown epitaxially on SrTiO{sub 3}(001) substrates. The recorded XPD polar scans are explained in the framework of multiple-scattering cluster calculations, where in general a very good agreement between experimental and theoretical data has been found. Results for all thin films are compatible with a tetragonally distorted cubic perovskite structure with similar MnO{sub 6} network. Strong evidence for Mn-site termination was found in all thin films. Dopant locations on A-type sites were clearly confirmed for Sr in LSMO and Ca in LCMO films by means of XPD polar scans. The absence of surface-sensitive Ce3d diffraction features for Ce in LCeMO points to non-equivalent Ce sites and related near-surface disorder.

  17. Site-specific growth of Au particles on ZnO nanopyramids under ultraviolet illumination.

    PubMed

    Yao, Ke Xin; Liu, Xin; Zhao, Lan; Zeng, Hua Chun; Han, Yu

    2011-10-01

    In this work, wurtzite ZnO nanocrystals with unique "pyramid" morphology were firstly prepared via solvothermal synthesis. It was determined that the ZnO nanopyramids are grown along the polar c-axis with the vertexes pointing to the [001] direction. When the mixture of ZnO nanopyramids and Au precursor (HAuCl(4)) was exposed to ultraviolet (UV) illumination, Au particles were site-specifically formed on the vertexes of ZnO nanopyramids. The obtained Au/ZnO nanocomposite showed significantly enhanced photocatalytic activity as compared to the bare ZnO nanopyramids. First-principles based calculations well explained the formation of ZnO nanopyramids as well as the site-specific growth of Au, and revealed that during the photocatalysis process the Au particles can accommodate photoelectrons and thus facilitate the charge separation. PMID:21870000

  18. X-ray diffraction and photoelectron spectroscopy studies of MoO 2 as catalyst for the partial oxidation of isooctane

    NASA Astrophysics Data System (ADS)

    Marin-Flores, Oscar; Scudiero, L.; Ha, Su

    2009-08-01

    X-ray diffraction (XRD), X-ray photoemission (XPS) as well as ultraviolet photoemission (UPS) spectroscopy experiments on MoO 2 powders were carried out to examine the bulk, the core level energies, and the electronic structure of MoO 2 samples that were employed as catalysts for the partial oxidation of isooctane. Five fresh 0.5-g MoO 2 samples were exposed for 0, 0.5, 9, 20, and 43 h to identical reforming environments and their spent samples were analyzed using the techniques mentioned above. Our results indicate the rapid appearance of an intermediate Mo phase with a binding energy of 228.5 eV and whose concentration progressively increases with time. The oxidation state for this new phase was graphically estimated to approximately +2.6 and assigned to the compound Mo 2O 3, which forms on the catalyst surface as a result of its exposure to the reforming environment. The electronic structure probed by UPS reveals two bands, one at 1.62 eV and another at 0.55 eV below the Fermi level, that decrease with the increasing time on stream. These results correlate very well with the drop in the catalytic performance of MoO 2 for the partial oxidation of isooctane and with the decline in the concentration of dioxide (Mo 4+) detected not only on the catalyst surface, but also in the bulk structure, as confirmed by our XRD analysis.

  19. SITE-SPECIFIC CHARACTERIZATION OF SOIL RADON POTENTIALS

    EPA Science Inventory

    The report presents a theoretical basis for measuring site-specific radon potentials. However, the empirical measurements suggest that the precision of such measurements is marginal, leaving an uncertainty of about a factor of 2 in site-specific estimates. Although this may be us...

  20. Enhancing adoption of site-specific variable rate sprinkler systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    More than twenty years of private and public research on site-specific variable-rate sprinkler irrigation (SS-VRI) has resulted in very limited commercial adoption of the technology. Documented and proven water conservation strategies using site-specific irrigation are quite limited, and its cost-ef...

  1. Site-Specific Weed Management: Myth or Magic?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Site-specific weed management (SSWM) is a potential method to reduce the risks of herbicide use on water quality and public health without impacting crop yield. With site-specific weed management, areas of the field are left untreated where control is not economically justified. Where control is nee...

  2. Site Specific Management of Cotton Production in the United States

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Site-specific management or precision agriculture, as it is evolving in large-scale crop production, offers promising new methods for managing cotton production for optimized yields, maximized profitability, and minimized environmental pollution. However, adaptation of site-specific theory and meth...

  3. Site-specific crop management using geophysical proximal sensors

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Key components of site-specific crop management are (i) identifying the site-specific factors that influence within-field crop yield variation and (ii) spatially characterizing those factors. Geo-referenced measurements of apparent soil electrical conductivity (ECa) provide a potential means of cha...

  4. Double clicking for site-specific coupling of multiple enzymes.

    PubMed

    Lim, Sung In; Cho, Jinhwan; Kwon, Inchan

    2015-09-14

    A method to site-specifically couple multiple enzymes is reported. The approach is based on the site-specific incorporation of a clickable non-natural amino acid into enzymes and two compatible click reactions. The multi-enzyme reaction system exhibited enhanced catalytic efficiency over the respective free enzymes. PMID:26191550

  5. 77 FR 22772 - Environmental Management Site-Specific Advisory Board

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-17

    ... Environmental Management Site-Specific Advisory Board AGENCY: Office of Environmental Management, Department of... Administration, notice is hereby given that the Environmental Management Site-Specific Advisory Board (EM SSAB... recommendations to the Assistant Secretary for Environmental Management (EM) concerning issues affecting the......

  6. Epitaxial BaTiO{sub 3}(100) films on Pt(100): A low-energy electron diffraction, scanning tunneling microscopy, and x-ray photoelectron spectroscopy study

    SciTech Connect

    Foerster, Stefan; Huth, Michael; Schindler, Karl-Michael; Widdra, Wolf

    2011-09-14

    The growth of epitaxial ultrathin BaTiO{sub 3} films on a Pt(100) substrate has been studied by scanning tunneling microscopy (STM), low-energy electron diffraction (LEED), and x-ray photoelectron spectroscopy (XPS). The films have been prepared by radio-frequency-assisted magnetron sputter deposition at room temperature and develop a long-range order upon annealing at 900 K in O{sub 2}. By adjusting the Ar and O{sub 2} partial pressures of the sputter gas, the stoichiometry was tuned to match that of a BaTiO{sub 3}(100) single crystal as determined by XPS. STM reveals the growth of continuous BaTiO{sub 3} films with unit cell high islands on top. With LEED already for monolayer thicknesses, the formation of a BaTiO{sub 3}(100)-(1 x 1) structure has been observed. Films of 2-3 unit cell thickness show a brilliant (1 x 1) LEED pattern for which an extended set of LEED I-V data has been acquired. At temperatures above 1050 K the BaTiO{sub 3} thin film starts to decay by formation of vacancy islands. In addition (4 x 4) and (3 x 3) surface reconstructions develop upon prolonged heating.

  7. Site-specific recombinases as tools for heterologous gene integration.

    PubMed

    Hirano, Nobutaka; Muroi, Tetsurou; Takahashi, Hideo; Haruki, Mitsuru

    2011-10-01

    Site-specific recombinases are the enzymes that catalyze site-specific recombination between two specific DNA sequences to mediate DNA integration, excision, resolution, or inversion and that play a pivotal role in the life cycles of many microorganisms including bacteria and bacteriophages. These enzymes are classified as tyrosine-type or serine-type recombinases based on whether a tyrosine or serine residue mediates catalysis. All known tyrosine-type recombinases catalyze the formation of a Holliday junction intermediate, whereas the catalytic mechanism of all known serine-type recombinases includes the 180° rotation and rejoining of cleaved substrate DNAs. Both recombinase families are further subdivided into two families; the tyrosine-type recombinases are subdivided by the recombination directionality, and the serine-type recombinases are subdivided by the protein size. Over more than two decades, many different site-specific recombinases have been applied to in vivo genome engineering, and some of them have been used successfully to mediate integration, deletion, or inversion in a wide variety of heterologous genomes, including those from bacteria to higher eukaryotes. Here, we review the recombination mechanisms of the best characterized recombinases in each site-specific recombinase family and recent advances in the application of these recombinases to genomic manipulation, especially manipulations involving site-specific gene integration into heterologous genomes. PMID:21822899

  8. Site-specific growth of Au particles on ZnO nanopyramids under ultraviolet illumination

    NASA Astrophysics Data System (ADS)

    Yao, Ke Xin; Liu, Xin; Zhao, Lan; Zeng, Hua Chun; Han, Yu

    2011-10-01

    In this work, wurtzite ZnO nanocrystals with unique ``pyramid'' morphology were firstly prepared via solvothermal synthesis. It was determined that the ZnO nanopyramids are grown along the polar c-axis with the vertexes pointing to the [001] direction. When the mixture of ZnO nanopyramids and Au precursor (HAuCl4) was exposed to ultraviolet (UV) illumination, Au particles were site-specifically formed on the vertexes of ZnO nanopyramids. The obtained Au/ZnO nanocomposite showed significantly enhanced photocatalytic activity as compared to the bare ZnO nanopyramids. First-principles based calculations well explained the formation of ZnO nanopyramids as well as the site-specific growth of Au, and revealed that during the photocatalysis process the Au particles can accommodate photoelectrons and thus facilitate the charge separation.In this work, wurtzite ZnO nanocrystals with unique ``pyramid'' morphology were firstly prepared via solvothermal synthesis. It was determined that the ZnO nanopyramids are grown along the polar c-axis with the vertexes pointing to the [001] direction. When the mixture of ZnO nanopyramids and Au precursor (HAuCl4) was exposed to ultraviolet (UV) illumination, Au particles were site-specifically formed on the vertexes of ZnO nanopyramids. The obtained Au/ZnO nanocomposite showed significantly enhanced photocatalytic activity as compared to the bare ZnO nanopyramids. First-principles based calculations well explained the formation of ZnO nanopyramids as well as the site-specific growth of Au, and revealed that during the photocatalysis process the Au particles can accommodate photoelectrons and thus facilitate the charge separation. Electronic supplementary information (ESI) available: TEM images of Au/ZnO nanocomposites with Au nanoparticles in different sizes, density of states of Au55 and Au20 deposited on ZnO (001) surface, and the first-principles calculation details. See DOI: 10.1039/c1nr10685f

  9. Utilization of Site-Specific Recombination in Biopharmaceutical Production

    PubMed Central

    Ahmadi, Maryam; Damavandi, Narges; Akbari, Mohammad Reza; Davami, Fatemeh

    2016-01-01

    Mammalian expression systems, due to their capacity in post-translational modification, are preferred systems for biopharmaceutical protein production. Several recombinant protein systems have been introduced to the market, most of which are under clinical development. In spite of significant improvements such as cell line engineering, introducing novel expression methods, gene silencing and process development, expression level is unpredictable and unstable because of the random location of integration in the genome. Site-specific recombination techniques are capable of producing stable and high producer clonal cells; therefore, they are gaining more importance in the biopharmaceutical production. Site-specific recombination methods increase the recombinant protein production by specifically inserting a vector at a locus with specific expression trait. The present review focused on the latest developments in site-specific recombination techniques, their specific features and comparisons. PMID:26602035

  10. Combined Approaches to Site-Specific Modification of RNA

    PubMed Central

    Chow, Christine S.; Mahto, Santosh K.; Lamichhane, Tek N.

    2008-01-01

    Both natural and unnatural modifications in RNA are of interest to biologists and chemists. More than 100 different analogs of the four standard RNA nucleosides have been identified in nature. Unnatural modifications are useful for structure and mechanistic studies of RNA. This Review highlights chemical, enzymatic, and combined (semisynthesis) approaches to generate site-specifically modified RNAs. The availability of these methods for site-specific modifications of RNAs of all sizes is important in order to study the relationships between RNA chemical composition, structure, and function. PMID:18177002

  11. Multispectral Imaging Technology for Site-Specific Crop Fertilization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Agricultural fields are variable and require site-specific crop management. Nitrogen (N) is an essential nutrient required for plant growth and is a major component of the chlorophyll molecule enhancing photosynthesis. However, excessive N fertilizer leaches into groundwater and creates serious envi...

  12. Uncertainty Analysis with Site Specific Groundwater Models: Experiences and Observations

    SciTech Connect

    Brewer, K.

    2003-07-15

    Groundwater flow and transport predictions are a major component of remedial action evaluations for contaminated groundwater at the Savannah River Site. Because all groundwater modeling results are subject to uncertainty from various causes; quantification of the level of uncertainty in the modeling predictions is beneficial to project decision makers. Complex site-specific models present formidable challenges for implementing an uncertainty analysis.

  13. Wireless Site-specific Irrigation - The Future of Intelligent Agriculture

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A wireless site-specific irrigation system was developed with a distributed wireless sensor network. The system allows growers to remotely access field conditions and an irrigation operation at the home or office via wireless radio communication, directing individual sprinklers on how much water to ...

  14. Site-Specific GlcNAcylation of Human Erythrocyte Proteins

    PubMed Central

    Wang, Zihao; Park, Kyoungsook; Comer, Frank; Hsieh-Wilson, Linda C.; Saudek, Christopher D.; Hart, Gerald W.

    2009-01-01

    OBJECTIVE—O-linked N-acetylglucosamine (O-GlcNAc) is upregulated in diabetic tissues and plays a role in insulin resistance and glucose toxicity. Here, we investigated the extent of GlcNAcylation on human erythrocyte proteins and compared site-specific GlcNAcylation on erythrocyte proteins from diabetic and normal individuals. RESEARCH DESIGN AND METHODS—GlcNAcylated erythrocyte proteins or GlcNAcylated peptides were tagged and selectively enriched by a chemoenzymatic approach and identified by mass spectrometry. The enrichment approach was combined with solid-phase chemical derivatization and isotopic labeling to detect O-GlcNAc modification sites and to compare site-specific O-GlcNAc occupancy levels between normal and diabetic erythrocyte proteins. RESULTS—The enzymes that catalyze the cycling (addition and removal) of O-GlcNAc were detected in human erythrocytes. Twenty-five GlcNAcylated erythrocyte proteins were identified. Protein expression levels were compared between diabetic and normal erythrocytes. Thirty-five O-GlcNAc sites were reproducibly identified, and their site-specific O-GlcNAc occupancy ratios were calculated. CONCLUSIONS—GlcNAcylation is differentially regulated at individual sites on erythrocyte proteins in response to glycemic status. These data suggest not only that site-specific O-GlcNAc levels reflect the glycemic status of an individual but also that O-GlcNAc site occupancy on erythrocyte proteins may be eventually useful as a diagnostic tool for the early detection of diabetes. PMID:18984734

  15. Delineating site-specific management units with proximal sensors

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Conventional farming uniformly manages fields with no consideration for spatial variability. This causes reduced productivity, misuse of finite resources (e.g., water and fertilizer), and detriment impacts on the environment. Site-specific management units (SSMUs) have been proposed as a means of ...

  16. Invasive Weed Management Is Site-Specific Weed Management.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Site-specific weed management in crops and invasive weed management in natural lands and rangelands appear to be unrelated research areas but there are many connections in the research problems, approaches and solutions. An obvious link is technology. The technology of precision agriculture - GPS, ...

  17. Adoption of site-specific variable rate sprinkler irrigation systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    More than twenty years of private and public research on site-specific variable-rate sprinkler irrigation (SS-VRI) technology has resulted in limited commercial adoption of the technology. Competing patents, liability and proprietary software have affected industry’s willingness to move into a new t...

  18. Evaluation of potential water conservation using site-specific irrigation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    With the advent of site-specific variable-rate irrigation (VRI) systems, irrigation can be spatially managed within sub-field-sized zones. Spatial irrigation management can optimize spatial water use efficiency and may conserve water. Spatial VRI systems are currently being managed by consultants ...

  19. Site-Specific Covalent Labeling of RNA by Enzymatic Transglycosylation.

    PubMed

    Alexander, Seth C; Busby, Kayla N; Cole, Christian M; Zhou, Cun Yu; Devaraj, Neal K

    2015-10-14

    We demonstrate the site-specific incorporation of nucleobase derivatives bearing fluorophores or affinity labels into a short RNA stem loop recognition motif by exchange of a guanine residue. The RNA-TAG (transglycosylation at guanosine) is carried out by a bacterial (E. coli) tRNA guanine transglycosylase (TGT), whose natural substrate is the nitrogenous base PreQ1. Remarkably, we have successfully incorporated large functional groups including biotin, BODIPY, thiazole orange, and Cy7 through a polyethylene glycol linker attached to the exocyclic amine of PreQ1. Larger RNAs, such as mRNA transcripts, can be site-specifically labeled if they possess the 17-nucleotide hairpin recognition motif. The RNA-TAG methodology could facilitate the detection and manipulation of RNA molecules by enabling the direct incorporation of functional artificial nucleobases using a simple hairpin recognition element. PMID:26393285

  20. Adapter Reagents for Protein Site Specific Dye Labeling

    PubMed Central

    Thompson, Darren A.; Evans, Eric G. B.; Kasza, Tomas; Millhauser, Glenn L.; Dawson, Philip E.

    2016-01-01

    Chemoselective protein labeling remains a significant challenge in chemical biology. Although many selective labeling chemistries have been reported, the practicalities of matching the reaction with appropriately functionalized proteins and labeling reagents is often a challenge. For example, we encountered the challenge of site specifically labeling the cellular form of the murine Prion protein with a fluorescent dye. To facilitate this labeling, a protein was expressed with site specific p-acetylphenylalanine. However, the utility of this aceto-phenone reactive group is hampered by the severe lack of commercially available aminooxy fluorophores. Here we outline a general strategy for the efficient solid phase synthesis of adapter reagents capable of converting maleimido-labels into aminooxy or azide functional groups that can be further tuned for desired length or solubility properties. The utility of the adapter strategy is demonstrated in the context of fluorescent labeling of the murine Prion protein through an adapted aminooxy-Alexa dye. PMID:24599728

  1. Chemoenzymatic Methods for Site-Specific Protein Modification

    PubMed Central

    Rabuka, David

    2010-01-01

    In the past decade, numerous chemical technologies have been developed to allow the site-specific post-translational modification of proteins. Traditionally covalent chemical protein modification has been accomplished by the attachment of synthetic groups to nucleophilic amino acids on protein surfaces. These chemistries, however, are rarely sufficiently selective to distinguish one residue within a literal sea of chemical functionality. One solution to this problem is to introduce a unique chemical handle into the target protein that is orthogonal to the remainder of the proteome. In practice, this handle can be a novel peptide sequence, which forms a “tag” that is selectively and irreversibly modified by enzymes. Furthermore, if the enzymes can tolerate substrate analogs, it becomes possible to engineer chemically modified proteins in a site-specific fashion. This review details the significant progress in creating techniques for the chemoenzymatic generation of protein-small molecule constructs and provides examples of novel applications of these methodologies. PMID:21030291

  2. Site-specific gene modification by PNAs conjugated to psoralen.

    PubMed

    Kim, Ki-Hyun; Nielsen, Peter E; Glazer, Peter M

    2006-01-10

    DNA-binding molecules, including triplex-forming oligonucleotides (TFOs) and peptide nucleic acids (PNAs), can be utilized to introduce site-specific mutations or to promote recombination at selected genomic sites. To further evaluate the utility of PNAs for site-specific gene modification, we tested dimeric bis-PNAs conjugated to psoralen. These PNAs are designed to form a triplex-invasion complex within the supF reporter gene in an episomal shuttle vector and to direct site-specific photoadduct formation by the conjugated psoralen. The psoralen-bis-PNA conjugate was found to direct photoadduct formation to the intended 5'-TpA base step next to the PNA-binding site, and the photoadduct formation efficiency displayed both concentration and UVA irradiation dependence. The effect of PNA-targeted photoadducts in a mammalian system was tested by SV40-based shuttle vector assay. After in vitro binding, we found that photoadducts directed by PNAs conjugated to psoralen-induced mutations at frequencies in the range of 0.46%, 6.5-fold above the background. In a protocol for intracellular gene targeting in the episomal shuttle vector, the psoralen-PNA-induced mutation frequency was 0.13%, 3.5-fold higher than the background. Most of the induced mutations were deletions and single-base-pair substitutions at or adjacent to the targeted PNA-binding and photoadduct-formation sites. When the results are taken together, they demonstrate the ability of bis-PNAs conjugated with psoralen to mediate site-specific gene modification, and they further support the development of PNAs as tools for gene-targeting applications. PMID:16388608

  3. A general approach to site-specific antibody drug conjugates

    PubMed Central

    Tian, Feng; Lu, Yingchun; Manibusan, Anthony; Sellers, Aaron; Tran, Hon; Sun, Ying; Phuong, Trung; Barnett, Richard; Hehli, Brad; Song, Frank; DeGuzman, Michael J.; Ensari, Semsi; Pinkstaff, Jason K.; Sullivan, Lorraine M.; Biroc, Sandra L.; Cho, Ho; Schultz, Peter G.; DiJoseph, John; Dougher, Maureen; Ma, Dangshe; Dushin, Russell; Leal, Mauricio; Tchistiakova, Lioudmila; Feyfant, Eric; Gerber, Hans-Peter; Sapra, Puja

    2014-01-01

    Using an expanded genetic code, antibodies with site-specifically incorporated nonnative amino acids were produced in stable cell lines derived from a CHO cell line with titers over 1 g/L. Using anti-5T4 and anti-Her2 antibodies as model systems, site-specific antibody drug conjugates (NDCs) were produced, via oxime bond formation between ketones on the side chain of the incorporated nonnative amino acid and hydroxylamine functionalized monomethyl auristatin D with either protease-cleavable or noncleavable linkers. When noncleavable linkers were used, these conjugates were highly stable and displayed improved in vitro efficacy as well as in vivo efficacy and pharmacokinetic stability in rodent models relative to conventional antibody drug conjugates conjugated through either engineered surface-exposed or reduced interchain disulfide bond cysteine residues. The advantages of the oxime-bonded, site-specific NDCs were even more apparent when low–antigen-expressing (2+) target cell lines were used in the comparative studies. NDCs generated with protease-cleavable linkers demonstrated that the site of conjugation had a significant impact on the stability of these rationally designed prodrug linkers. In a single-dose rat toxicology study, a site-specific anti-Her2 NDC was well tolerated at dose levels up to 90 mg/kg. These experiments support the notion that chemically defined antibody conjugates can be synthesized in commercially relevant yields and can lead to antibody drug conjugates with improved properties relative to the heterogeneous conjugates formed by nonspecific chemical modification. PMID:24443552

  4. A general approach to site-specific antibody drug conjugates.

    PubMed

    Tian, Feng; Lu, Yingchun; Manibusan, Anthony; Sellers, Aaron; Tran, Hon; Sun, Ying; Phuong, Trung; Barnett, Richard; Hehli, Brad; Song, Frank; DeGuzman, Michael J; Ensari, Semsi; Pinkstaff, Jason K; Sullivan, Lorraine M; Biroc, Sandra L; Cho, Ho; Schultz, Peter G; DiJoseph, John; Dougher, Maureen; Ma, Dangshe; Dushin, Russell; Leal, Mauricio; Tchistiakova, Lioudmila; Feyfant, Eric; Gerber, Hans-Peter; Sapra, Puja

    2014-02-01

    Using an expanded genetic code, antibodies with site-specifically incorporated nonnative amino acids were produced in stable cell lines derived from a CHO cell line with titers over 1 g/L. Using anti-5T4 and anti-Her2 antibodies as model systems, site-specific antibody drug conjugates (NDCs) were produced, via oxime bond formation between ketones on the side chain of the incorporated nonnative amino acid and hydroxylamine functionalized monomethyl auristatin D with either protease-cleavable or noncleavable linkers. When noncleavable linkers were used, these conjugates were highly stable and displayed improved in vitro efficacy as well as in vivo efficacy and pharmacokinetic stability in rodent models relative to conventional antibody drug conjugates conjugated through either engineered surface-exposed or reduced interchain disulfide bond cysteine residues. The advantages of the oxime-bonded, site-specific NDCs were even more apparent when low-antigen-expressing (2+) target cell lines were used in the comparative studies. NDCs generated with protease-cleavable linkers demonstrated that the site of conjugation had a significant impact on the stability of these rationally designed prodrug linkers. In a single-dose rat toxicology study, a site-specific anti-Her2 NDC was well tolerated at dose levels up to 90 mg/kg. These experiments support the notion that chemically defined antibody conjugates can be synthesized in commercially relevant yields and can lead to antibody drug conjugates with improved properties relative to the heterogeneous conjugates formed by nonspecific chemical modification. PMID:24443552

  5. Pretargeted PET Imaging Using a Site-Specifically Labeled Immunoconjugate.

    PubMed

    Cook, Brendon E; Adumeau, Pierre; Membreno, Rosemery; Carnazza, Kathryn E; Brand, Christian; Reiner, Thomas; Agnew, Brian J; Lewis, Jason S; Zeglis, Brian M

    2016-08-17

    In recent years, both site-specific bioconjugation techniques and bioorthogonal pretargeting strategies have emerged as exciting technologies with the potential to improve the safety and efficacy of antibody-based nuclear imaging. In the work at hand, we have combined these two approaches to create a pretargeted PET imaging strategy based on the rapid and bioorthogonal inverse electron demand Diels-Alder reaction between a (64)Cu-labeled tetrazine radioligand ((64)Cu-Tz-SarAr) and a site-specifically modified huA33-trans-cyclooctene immunoconjugate ((ss)huA33-PEG12-TCO). A bioconjugation strategy that harnesses enzymatic transformations and strain-promoted azide-alkyne click chemistry was used to site-specifically append PEGylated TCO moieties to the heavy chain glycans of the colorectal cancer-targeting huA33 antibody. Preclinical in vivo validation studies were performed in athymic nude mice bearing A33 antigen-expressing SW1222 human colorectal carcinoma xenografts. To this end, mice were administered (ss)huA33-PEG12-TCO via tail vein injection and-following accumulation intervals of 24 or 48 h-(64)Cu-Tz-SarAr. PET imaging and biodistribution studies reveal that this strategy clearly delineates tumor tissue as early as 1 h post-injection (6.7 ± 1.7%ID/g at 1 h p.i.), producing images with excellent contrast and high tumor-to-background activity concentration ratios (tumor:muscle = 21.5 ± 5.6 at 24 h p.i.). Furthermore, dosimetric calculations illustrate that this pretargeting approach produces only a fraction of the overall effective dose (0.0214 mSv/MBq; 0.079 rem/mCi) of directly labeled radioimmunoconjugates. Ultimately, this method effectively facilitates the high contrast pretargeted PET imaging of colorectal carcinoma using a site-specifically modified immunoconjugate. PMID:27356886

  6. POLYMER DELIVERY SYSTEMS FOR SITE-SPECIFIC GENOME EDITING

    PubMed Central

    McNeer, Nicole Ali; Schleifman, Erica B.; Glazer, Peter M.; Saltzman, W. Mark

    2011-01-01

    Triplex-forming peptide nucleic acids (PNAs) can be used to coordinate the recombination of short 50–60 bp “donor DNA” fragments into genomic DNA, resulting in site-specific correction of genetic mutations or the introduction of advantageous genetic modifications. Site-specific gene editing in hematopoietic stem and progenitor cells (HSPCs) could result in the treatment or cure of inherited disorders of the blood such as β-thalassemia or sickle cell anemia. Gene editing in HSPCs and differentiated T cells could also help combat HIV infection by modifying the HIV co-receptor CCR5, which is necessary for R5-tropic HIV entry. However, translation of genome modification technologies to clinical practice is limited by challenges in intracellular delivery, especially in difficult-to-transfect hematolymphoid cells. Here, we review the use of engineered biodegradable polymer nanoparticles for site-specific genome editing in human hematopoietic cells, which represent a promising approach for ex vivo and in vivo gene therapy. PMID:21620910

  7. Site specific atomic polarizabilities in endohedral fullerenes and carbon onions.

    PubMed

    Zope, Rajendra R; Bhusal, Shusil; Basurto, Luis; Baruah, Tunna; Jackson, Koblar

    2015-08-28

    We investigate the polarizability of trimetallic nitride endohedral fullerenes by partitioning the total polarizability into site specific components. This analysis indicates that the polarizability of the endohedral fullerene is essentially due to the outer fullerene cage and has insignificant contribution from the encapsulated unit. Thus, the outer fullerene cages effectively shield the encapsulated clusters and behave like Faraday cages. The polarizability of endohedral fullerenes is slightly smaller than the polarizability of the corresponding bare carbon fullerenes. The application of the site specific polarizabilities to C60@C240 and C60@C180 onions shows that, compared to the polarizability of isolated C60 fullerene, the encapsulation of the C60 in C240 and C180 fullerenes reduces its polarizability by 75% and 83%, respectively. The differences in the polarizability of C60 in the two onions is a result of differences in the bonding (intershell electron transfer), fullerene shell relaxations, and intershell separations. The site specific analysis further shows that the outer atoms in a fullerene shell contribute most to the fullerene polarizability. PMID:26328842

  8. Site specific atomic polarizabilities in endohedral fullerenes and carbon onions

    NASA Astrophysics Data System (ADS)

    Zope, Rajendra R.; Bhusal, Shusil; Basurto, Luis; Baruah, Tunna; Jackson, Koblar

    2015-08-01

    We investigate the polarizability of trimetallic nitride endohedral fullerenes by partitioning the total polarizability into site specific components. This analysis indicates that the polarizability of the endohedral fullerene is essentially due to the outer fullerene cage and has insignificant contribution from the encapsulated unit. Thus, the outer fullerene cages effectively shield the encapsulated clusters and behave like Faraday cages. The polarizability of endohedral fullerenes is slightly smaller than the polarizability of the corresponding bare carbon fullerenes. The application of the site specific polarizabilities to C60@C240 and C60@C180 onions shows that, compared to the polarizability of isolated C60 fullerene, the encapsulation of the C60 in C240 and C180 fullerenes reduces its polarizability by 75% and 83%, respectively. The differences in the polarizability of C60 in the two onions is a result of differences in the bonding (intershell electron transfer), fullerene shell relaxations, and intershell separations. The site specific analysis further shows that the outer atoms in a fullerene shell contribute most to the fullerene polarizability.

  9. Site specific atomic polarizabilities in endohedral fullerenes and carbon onions

    SciTech Connect

    Zope, Rajendra R. Baruah, Tunna; Bhusal, Shusil; Basurto, Luis; Jackson, Koblar

    2015-08-28

    We investigate the polarizability of trimetallic nitride endohedral fullerenes by partitioning the total polarizability into site specific components. This analysis indicates that the polarizability of the endohedral fullerene is essentially due to the outer fullerene cage and has insignificant contribution from the encapsulated unit. Thus, the outer fullerene cages effectively shield the encapsulated clusters and behave like Faraday cages. The polarizability of endohedral fullerenes is slightly smaller than the polarizability of the corresponding bare carbon fullerenes. The application of the site specific polarizabilities to C{sub 60}@C{sub 240} and C{sub 60}@C{sub 180} onions shows that, compared to the polarizability of isolated C{sub 60} fullerene, the encapsulation of the C{sub 60} in C{sub 240} and C{sub 180} fullerenes reduces its polarizability by 75% and 83%, respectively. The differences in the polarizability of C{sub 60} in the two onions is a result of differences in the bonding (intershell electron transfer), fullerene shell relaxations, and intershell separations. The site specific analysis further shows that the outer atoms in a fullerene shell contribute most to the fullerene polarizability.

  10. Chemical tags for site-specific fluorescent labeling of biomolecules.

    PubMed

    Freidel, Christoph; Kaloyanova, Stefka; Peneva, Kalina

    2016-06-01

    This review focuses on the various approaches to covalently attach a chromophore to a biomolecule of interest in site-specific manner. Novel methods like inverse electron-demand Diels-Alder reaction, Pictet-Spengler ligation and enzyme tags like SNAP and Halo-tags are critically discussed and compared to established techniques like copper-free click reaction and native chemical ligation. Selected examples in which the tags have been exploited for in vitro or in vivo imaging are reviewed and evaluated. PMID:26969255

  11. Site Specific Probable Maximum Precipitation Estimates and Professional Judgement

    NASA Astrophysics Data System (ADS)

    Hayes, B. D.; Kao, S. C.; Kanney, J. F.; Quinlan, K. R.; DeNeale, S. T.

    2015-12-01

    State and federal regulatory authorities currently rely upon the US National Weather Service Hydrometeorological Reports (HMRs) to determine probable maximum precipitation (PMP) estimates (i.e., rainfall depths and durations) for estimating flooding hazards for relatively broad regions in the US. PMP estimates for the contributing watersheds upstream of vulnerable facilities are used to estimate riverine flooding hazards while site-specific estimates for small water sheds are appropriate for individual facilities such as nuclear power plants. The HMRs are often criticized due to their limitations on basin size, questionable applicability in regions affected by orographic effects, their lack of consist methods, and generally by their age. HMR-51 for generalized PMP estimates for the United States east of the 105th meridian, was published in 1978 and is sometimes perceived as overly conservative. The US Nuclear Regulatory Commission (NRC), is currently reviewing several flood hazard evaluation reports that rely on site specific PMP estimates that have been commercially developed. As such, NRC has recently investigated key areas of expert judgement via a generic audit and one in-depth site specific review as they relate to identifying and quantifying actual and potential storm moisture sources, determining storm transposition limits, and adjusting available moisture during storm transposition. Though much of the approach reviewed was considered a logical extension of HMRs, two key points of expert judgement stood out for further in-depth review. The first relates primarily to small storms and the use of a heuristic for storm representative dew point adjustment developed for the Electric Power Research Institute by North American Weather Consultants in 1993 in order to harmonize historic storms for which only 12 hour dew point data was available with more recent storms in a single database. The second issue relates to the use of climatological averages for spatially

  12. Site Specific Genetic Incorporation of Azidophenylalanine in Schizosaccharomyces pombe

    PubMed Central

    Shao, Nan; Singh, N. Sadananda; Slade, Susan E.; Jones, Alexandra M. E.; Balasubramanian, Mohan K.

    2015-01-01

    The diversity of protein functions is impacted in significant part by the chemical properties of the twenty amino acids, which are used as building blocks for nearly all proteins. The ability to incorporate unnatural amino acids (UAA) into proteins in a site specific manner can vastly expand the repertoire of protein functions and also allows detailed analysis of protein function. In recent years UAAs have been incorporated in a site-specific manner into proteins in a number of organisms. In nearly all cases, the amber codon is used as a sense codon, and an orthogonal tRNA/aminoacyl-tRNA synthetase (RS) pair is used to generate amber suppressing tRNAs charged with the UAA. In this work, we have developed tools to incorporate the cross-linking amino acid azido-phenylalanine (AzF) through the use of bacterial tRNATyr and a modified version of TyrRS, AzFRS, in Schizosaccharomyces pombe, which is an attractive model organism for the study of cell behavior and function. We have incorporated AzF into three different proteins. We show that the majority of AzF is modified to amino-phenyl alanine, but protein cross-linking was still observed. These studies set the stage for exploitation of this new technology for the analysis of S. pombe proteins. PMID:26597962

  13. Site-specific antibody drug conjugates for cancer therapy

    PubMed Central

    Panowksi, Siler; Bhakta, Sunil; Raab, Helga; Polakis, Paul; Junutula, Jagath R

    2014-01-01

    Antibody therapeutics have revolutionized the treatment of cancer over the past two decades. Antibodies that specifically bind tumor surface antigens can be effective therapeutics; however, many unmodified antibodies lack therapeutic activity. These antibodies can instead be applied successfully as guided missiles to deliver potent cytotoxic drugs in the form of antibody drug conjugates (ADCs). The success of ADCs is dependent on four factors—target antigen, antibody, linker, and payload. The field has made great progress in these areas, marked by the recent approval by the US Food and Drug Administration of two ADCs, brentuximab vedotin (Adcetris®) and ado-trastuzumab emtansine (Kadcyla®). However, the therapeutic window for many ADCs that are currently in pre-clinical or clinical development remains narrow and further improvements may be required to enhance the therapeutic potential of these ADCs. Production of ADCs is an area where improvement is needed because current methods yield heterogeneous mixtures that may include 0–8 drug species per antibody molecule. Site-specific conjugation has been recently shown to eliminate heterogeneity, improve conjugate stability, and increase the therapeutic window. Here, we review and describe various site-specific conjugation strategies that are currently used for the production of ADCs, including use of engineered cysteine residues, unnatural amino acids, and enzymatic conjugation through glycotransferases and transglutaminases. In addition, we also summarize differences among these methods and highlight critical considerations when building next-generation ADC therapeutics. PMID:24423619

  14. Site-specific antibody drug conjugates for cancer therapy.

    PubMed

    Panowski, Siler; Bhakta, Sunil; Raab, Helga; Polakis, Paul; Junutula, Jagath R

    2014-01-01

    Antibody therapeutics have revolutionized the treatment of cancer over the past two decades. Antibodies that specifically bind tumor surface antigens can be effective therapeutics; however, many unmodified antibodies lack therapeutic activity. These antibodies can instead be applied successfully as guided missiles to deliver potent cytotoxic drugs in the form of antibody drug conjugates (ADCs). The success of ADCs is dependent on four factors--target antigen, antibody, linker, and payload. The field has made great progress in these areas, marked by the recent approval by the US Food and Drug Administration of two ADCs, brentuximab vedotin (Adcetris) and ado-trastuzumab emtansine (Kadcyla). However, the therapeutic window for many ADCs that are currently in pre-clinical or clinical development remains narrow and further improvements may be required to enhance the therapeutic potential of these ADCs. Production of ADCs is an area where improvement is needed because current methods yield heterogeneous mixtures that may include 0-8 drug species per antibody molecule. Site-specific conjugation has been recently shown to eliminate heterogeneity, improve conjugate stability, and increase the therapeutic window. Here, we review and describe various site-specific conjugation strategies that are currently used for the production of ADCs, including use of engineered cysteine residues, unnatural amino acids, and enzymatic conjugation through glycotransferases and transglutaminases. In addition, we also summarize differences among these methods and highlight critical considerations when building next-generation ADC therapeutics. PMID:24423619

  15. Site-specific calibration of the Hanford personnel neutron dosimeter

    SciTech Connect

    Endres, A.W.; Brackenbush, L.W.; Baumgartner, W.V.; Rathbone, B.A.

    1994-10-01

    A new personnel dosimetry system, employing a standard Hanford thermoluminescent dosimeter (TLD) and a combination dosimeter with both CR-39 nuclear track and TLD-albedo elements, is being implemented at Hanford. Measurements were made in workplace environments in order to verify the accuracy of the system and establish site-specific factors to account for the differences in dosimeter response between the workplace and calibration laboratory. Neutron measurements were performed using sources at Hanford`s Plutonium Finishing Plant under high-scatter conditions to calibrate the new neutron dosimeter design to site-specific neutron spectra. The dosimeter was also calibrated using bare and moderated {sup 252}Cf sources under low-scatter conditions available in the Hanford Calibration Laboratory. Dose equivalent rates in the workplace were calculated from spectrometer measurements using tissue equivalent proportional counter (TEPC) and multisphere spectrometers. The accuracy of the spectrometers was verified by measurements on neutron sources with calibrations directly traceable to the National Institute of Standards and Technology (NIST).

  16. Site-specific features influence sediment stability of intertidal flats

    NASA Astrophysics Data System (ADS)

    Defew, Emma C.; Tolhurst, Trevor J.; Paterson, David M.

    The factors that influence the sediment stability and the transport of estuarine mudflats are not yet fully understood but knowledge of them is essential in coastal engineering applications and pollution ecology studies. The suggestion that variation in predictive models of sediment stability might be due to site-specific characteristics is investigated using data from four estuarine mudflats (Eden Estuary, Scotland, the Biezelingsche Ham, Zandkreek, and Molenplaat mudflats in The Netherlands). These estuaries differ in their environmental conditions, macrofaunal species composition and local features (e.g. Enteromorpha mats, migratory biofilms). Stable and unstable sediments were compared, and mean chlorophyll-a concentrations and granulometry of the sediments were significantly different between the two groups. Step-wise multiple linear regressions were applied to the sediment stability data of all sites to establish the influences on erosion threshold of microphytobenthic biomass, water content, granulometry, organic carbon content and the abundance of dominant macrofaunal species. The stability of each site was influenced by different factors. Sediment stability of the Eden Estuary was affected by the Enteromorpha bloom; Biezelingsche Ham was influenced by the highly migratory nature of the diatom biofilms and the abundance of Corophium volutator; the polychaete worm Arenicola marina had a net negative effect on sediment stability of the Zandkreek; and the Molenplaat was influenced by microphytobenthic biomass. This research highlights the need for site-specific calibration of models and suggests that a universal proxy parameter for sediment stability is unlikely to be obtained.

  17. Site-specific analysis of dielectric properties of finite systems.

    SciTech Connect

    Jackson, K.; Yang, M.; Jellinek, J.; Chemistry; Central Michigan Univ.

    2007-12-06

    A new scheme for decomposing the total dipole moment and polarizability of a system into site-specific contributions is presented. The scheme is based on partitioning the system volume into cells associated with its atoms or groups of atoms. The site-specific dipole moments and polarizabilities are computed from the charge densities within the individual cells and the responses of these densities to an external electric field. These dipole moments and polarizabilities are further partitioned into local/dipole and charge-transfer components. The utility of the scheme is illustrated through analysis of the structure-/shape- and size-specific aspects of the dipole moments and polarizabilities of silicon clusters. It is shown that the polarizabilities associated with the individual constituent Si atoms vary considerably with the structure/shape of the cluster and the location of the atom or site within a given structure. Surface atoms, and especially those at edges, have larger polarizabilities than interior atoms. The overall contribution of the charge-transfer components to the total cluster polarizability increases with the cluster size. Finally, the anisotropy of the total polarizability correlates with the anisotropy of the cluster shape, and the charge-transfer component is the part dominantly responsible for the polarizability anisotropy.

  18. Measuring fluctuations in shear stretched DNAs using site specific labeling

    NASA Astrophysics Data System (ADS)

    Price, Allen; Graham, Thomas; Loparo, Joseph; Eaves, Joel

    2012-02-01

    We report a new technique for measuring the internal dynamics of surface tethered DNAs in shear flow. Previous studies have used end labeling or intercolating dyes which label the entire length of the DNA. Neither prior method can resolve the internal longitudinal fluctuations of the DNA. Our technique accomplishes this by site specific labeling of five sites in lambda phage DNA using EcoRI labeled with fluorescent quantum dots. We used our technique to determine the two point cross correlation functions of the longitudinal and transverse fluctuations of the DNA under shear flow. Our technique allows us to test current models of the non-equilibrium fluctuations of DNA in shear flow in a way previously inaccessible.

  19. Methods for generating phosphorylation site-specific immunological reagents

    DOEpatents

    Anderson, Carl W.; Appella, Ettore; Sakaguchi, Kazuyasu

    2001-01-01

    The present invention provides methods for generating phosphorylation site-specific immunological reagents. More specifically, a phosphopeptide mimetic is incorporated into a polypeptide in place of a phosphorylated amino acid. The polypeptide is used as antigen by standard methods to generate either monoclonal or polyclonal antibodies which cross-react with the naturally phosphorylated polypeptide. The phosphopeptide mimetic preferably contains a non-hydrolyzable linkage from the appropriate carbon atom of the amino acid residue to a phosphate group. A preferred linkage is a CF.sub.2 group. Such a linkage is used to generate the phosphoserine mimetic F.sub.2 Pab, which is incorporated into a polypeptide sequence derived from p53 to produce antibodies which recognize a specific phosphorylation state of p53. A CF.sub.2 group linkage is also used to produce the phosphothreonine mimetic F.sub.2 Pmb, and to produce the phosphotyrosine mimetic, F.sub.2 Pmp.

  20. Site-Specific Genome Engineering in Human Pluripotent Stem Cells.

    PubMed

    Merkert, Sylvia; Martin, Ulrich

    2016-01-01

    The possibility to generate patient-specific induced pluripotent stem cells (iPSCs) offers an unprecedented potential of applications in clinical therapy and medical research. Human iPSCs and their differentiated derivatives are tools for diseases modelling, drug discovery, safety pharmacology, and toxicology. Moreover, they allow for the engineering of bioartificial tissue and are promising candidates for cellular therapies. For many of these applications, the ability to genetically modify pluripotent stem cells (PSCs) is indispensable, but efficient site-specific and safe technologies for genetic engineering of PSCs were developed only recently. By now, customized engineered nucleases provide excellent tools for targeted genome editing, opening new perspectives for biomedical research and cellular therapies. PMID:27347935

  1. Cre-mediated site-specific recombination in zebrafish embryos.

    PubMed

    Thummel, Ryan; Burket, Christopher T; Brewer, Jeffrey L; Sarras, Michael P; Li, Li; Perry, Martin; McDermott, Jeffrey P; Sauer, Brian; Hyde, David R; Godwin, Alan R

    2005-08-01

    Cre-mediated site-specific recombination has become an invaluable tool for manipulation of the murine genome. The ability to conditionally activate gene expression or to generate chromosomal alterations with this same tool would greatly enhance zebrafish genetics. This study demonstrates that the HSP70 promoter can be used to inducibly control expression of an enhanced green fluorescent protein (EGFP) -Cre fusion protein. The EGFP-Cre fusion protein is capable of promoting recombination between lox sites in injected plasmids or in stably inherited transgenes as early as 2 hr post-heat shock induction. Finally, the levels of Cre expression achieved in a transgenic fish line carrying the HSP70-EGFP-cre transgene are compatible with viability and both male and female transgenic fish are fertile subsequent to induction of EGFP-Cre expression. Hence, our data suggests that Cre-mediated recombination is a viable means of manipulating gene expression in zebrafish. PMID:15977183

  2. Site-Specific Genome Engineering in Human Pluripotent Stem Cells

    PubMed Central

    Merkert, Sylvia; Martin, Ulrich

    2016-01-01

    The possibility to generate patient-specific induced pluripotent stem cells (iPSCs) offers an unprecedented potential of applications in clinical therapy and medical research. Human iPSCs and their differentiated derivatives are tools for diseases modelling, drug discovery, safety pharmacology, and toxicology. Moreover, they allow for the engineering of bioartificial tissue and are promising candidates for cellular therapies. For many of these applications, the ability to genetically modify pluripotent stem cells (PSCs) is indispensable, but efficient site-specific and safe technologies for genetic engineering of PSCs were developed only recently. By now, customized engineered nucleases provide excellent tools for targeted genome editing, opening new perspectives for biomedical research and cellular therapies. PMID:27347935

  3. Flow Shear Stress and Atherosclerosis: A Matter of Site Specificity

    PubMed Central

    Nigro, Patrizia; Abe, Jun-ichi

    2011-01-01

    Abstract It is well accepted that atherosclerosis occurs in a site-specific manner especially at branch points where disturbed blood flow (d-flow) predisposes to the development of plaques. Investigations both in vivo and in vitro have shown that d-flow is pro-atherogenic by promoting oxidative and inflammatory states in the artery wall. In contrast, steady laminar blood flow (s-flow) is atheroprotective by inhibition of oxidative stress and inflammation in the vessel wall. The mechanism for inflammation in endothelial cells (ECs) exposed to d-flow has been well studied and includes redox-dependent activation of apoptosis signal-regulating kinase 1 (ASK1) and Jun NH2-terminal kinase (JNK) that ultimately lead to the expression of adhesive molecules. In contrast, s-flow leads to the activation of the mitogen extracellular-signal-regulated kinase kinase 5/extracellular signal-regulated kinase-5 (MEK5/ERK5) pathway that prevents pro-inflammatory signaling. Important transcriptional events that reflect the pro-oxidant and pro-inflammatory condition of ECs in d-flow include the activation of activator protein 1 (AP-1) and nuclear factor kappaB (NFκB), whereas in s-flow, activation of Krüppel-like factor 2 (KLF2) and nuclear factor erythroid 2-like 2 (Nrf2) are dominant. Recent studies have shown that protein kinase c zeta (PKCζ) is highly activated under d-flow conditions and may represent a molecular switch for EC signaling and gene expression. The targeted modulation of proteins activated in a site-specific manner holds the promise for a new approach to limit atherosclerosis. Antioxid. Redox Signal. 15, 1405–1414. PMID:21050140

  4. The λ Integrase Site-specific Recombination Pathway.

    PubMed

    Landy, Arthur

    2015-04-01

    The site-specific recombinase encoded by bacteriophage λ (Int) is responsible for integrating and excising the viral chromosome into and out of the chromosome of its Escherichia coli host. Int carries out a reaction that is highly directional, tightly regulated, and depends upon an ensemble of accessory DNA bending proteins acting on 240 bp of DNA encoding 16 protein binding sites. This additional complexity enables two pathways, integrative and excisive recombination, whose opposite, and effectively irreversible, directions are dictated by different physiological and environmental signals. Int recombinase is a heterobivalent DNA binding protein and each of the four Int protomers, within a multiprotein 400 kDa recombinogenic complex, is thought to bind and, with the aid of DNA bending proteins, bridge one arm- and one core-type DNA site. In the 12 years since the publication of the last review focused solely on the λ site-specific recombination pathway in Mobile DNA II, there has been a great deal of progress in elucidating the molecular details of this pathway. The most dramatic advances in our understanding of the reaction have been in the area of X-ray crystallography where protein-DNA structures have now been determined for of all of the DNA-protein interfaces driving the Int pathway. Building on this foundation of structures, it has been possible to derive models for the assembly of components that determine the regulatory apparatus in the P-arm, and for the overall architectures that define excisive and integrative recombinogenic complexes. The most fundamental additional mechanistic insights derive from the application of hexapeptide inhibitors and single molecule kinetics. PMID:26104711

  5. Site Specific Analyses of a Spent Nuclear Fuel Transportation Accident

    SciTech Connect

    Biwer, B. M.; Chen, S. Y.

    2003-02-24

    The number of spent nuclear fuel (SNF) shipments is expected to increase significantly during the time period that the United States' inventory of SNF is sent to a final disposal site. Prior work estimated that the highest accident risks of a SNF shipping campaign to the proposed geologic repository at Yucca Mountain were in the corridor states, such as Illinois. The largest potential human health impacts would be expected to occur in areas with high population densities such as urban settings. Thus, our current study examined the human health impacts from the most plausible severe SNF transportation accidents in the Chicago metropolitan area. The RISKIND 2.0 program was used to model site-specific data for an area where the largest impacts might occur. The results have shown that the radiological human health consequences of a severe SNF rail transportation accident on average might be similar to one year of exposure to natural background radiation for those persons living a nd working in the most affected areas downwind of the actual accident location. For maximally exposed individuals, an exposure similar to about two years of exposure to natural background radiation was estimated. In addition to the accident probabilities being very low (approximately 1 chance in 10,000 or less during the entire shipping campaign), the actual human health impacts are expected to be lower if any of the accidents considered did occur, because the results are dependent on the specific location and weather conditions, such as wind speed and direction, that were selected to maximize the results. Also, comparison of the results of longer duration accident scenarios against U.S. Environmental Protection Agency guidelines was made to demonstrate the usefulness of this site-specific analysis for emergency planning purposes.

  6. Site-specific probing of charge transfer dynamics in organic photovoltaics

    SciTech Connect

    Arion, Tiberiu; Roth, Friedrich; Hussain, Zahid; Eberhardt, Wolfgang

    2015-03-23

    We report the site-specific probing of charge-transfer dynamics in a prototype system for organic photovoltaics (OPVs) by picosecond time-resolved X-ray photoelectron spectroscopy. A layered system consisting of approximately two monolayers of C{sub 60} deposited on top of a thin film of Copper-Phthalocyanine (CuPC) is excited by an optical pump pulse and the induced electronic dynamics are probed with 590 eV X-ray pulses. Charge transfer from the electron donor (CuPC) to the acceptor (C{sub 60}) and subsequent charge carrier dynamics are monitored by recording the time-dependent C 1s core level photoemission spectrum of the system. The arrival of electrons in the C{sub 60} layer is readily observed as a completely reversible, transient shift of the C{sub 60} associated C 1s core level, while the C 1s level of the CuPC remains unchanged. The capability to probe charge transfer and recombination dynamics in OPV assemblies directly in the time domain and from the perspective of well-defined domains is expected to open additional pathways to better understand and optimize the performance of this emerging technology.

  7. Site-specific probing of charge transfer dynamics in organic photovoltaics

    NASA Astrophysics Data System (ADS)

    Arion, Tiberiu; Neppl, Stefan; Roth, Friedrich; Shavorskiy, Andrey; Bluhm, Hendrik; Hussain, Zahid; Gessner, Oliver; Eberhardt, Wolfgang

    2015-03-01

    We report the site-specific probing of charge-transfer dynamics in a prototype system for organic photovoltaics (OPVs) by picosecond time-resolved X-ray photoelectron spectroscopy. A layered system consisting of approximately two monolayers of C60 deposited on top of a thin film of Copper-Phthalocyanine (CuPC) is excited by an optical pump pulse and the induced electronic dynamics are probed with 590 eV X-ray pulses. Charge transfer from the electron donor (CuPC) to the acceptor (C60) and subsequent charge carrier dynamics are monitored by recording the time-dependent C 1s core level photoemission spectrum of the system. The arrival of electrons in the C60 layer is readily observed as a completely reversible, transient shift of the C60 associated C 1s core level, while the C 1s level of the CuPC remains unchanged. The capability to probe charge transfer and recombination dynamics in OPV assemblies directly in the time domain and from the perspective of well-defined domains is expected to open additional pathways to better understand and optimize the performance of this emerging technology.

  8. Improving Site-Specific Radiological Performance Assessments - 13431

    SciTech Connect

    Tauxe, John; Black, Paul; Catlett, Kate; Lee, Robert; Perona, Ralph; Stockton, Tom; Sully, Mike

    2013-07-01

    An improved approach is presented for conducting complete and defensible radiological site-specific performance assessments (PAs) to support radioactive waste disposal decisions. The basic tenets of PA were initiated some thirty years ago, focusing on geologic disposals and evaluating compliance with regulations. Some of these regulations were inherently probabilistic (i.e., addressing uncertainty in a quantitative fashion), such as the containment requirements of the U.S. Environmental Protection Agency's (EPA's) 40 CFR 191, Environmental Radiation Protection Standards for Management and Disposal of Spent Nuclear Fuel, High-Level and Transuranic Radioactive Wastes, Chap. 191.13 [1]. Methods of analysis were developed to meet those requirements, but at their core early PAs used 'conservative' parameter values and modeling approaches. This limited the utility of such PAs to compliance evaluation, and did little to inform decisions about optimizing disposal, closure and long-term monitoring and maintenance, or, in general, maintaining doses 'as low as reasonably achievable' (ALARA). This basic approach to PA development in the United States was employed essentially unchanged through the end of the 20. century, principally by the U.S. Department of Energy (DOE). Performance assessments developed in support of private radioactive waste disposal operations, regulated by the U.S. Nuclear Regulatory Commission (NRC) and its agreement states, were typically not as sophisticated. Discussion of new approaches to PA is timely, since at the time of this writing, the DOE is in the midst of revising its Order 435.1, Radioactive Waste Management [2], and the NRC is revising 10 CFR 61, Licensing Requirements for Land Disposal of Radioactive Waste [3]. Over the previous decade, theoretical developments and improved computational technology have provided the foundation for integrating decision analysis (DA) concepts and objective-focused thinking, plus a Bayesian approach to

  9. Viral induction of site-specific chromosome damage.

    PubMed

    Fortunato, Elizabeth A; Spector, Deborah H

    2003-01-01

    The advent of advanced cell culture and cytogenetics techniques in the 1950s opened a new avenue for research on the pathogenic interactions between animal viruses and their hosts. Studies of many viruses revealed their ability to nonspecifically induce cytogenetic damage to their host cell's chromosomes. However, only three viruses, the oncogenic adenoviruses, herpes simplex virus (HSV) and human cytomegalovirus (HCMV), have been found to cause non-random, site-specific chromosomal damage. Adenovirus (Ad) type 12 induces fragility at four distinct loci (RNU1, RNU2, RN5S and PSU1) in many different types of human cells. A common feature of these loci is that they contain a repeated array of transcriptionally active genes encoding small structural RNAs. Site-specific induction of breaks also requires the virally encoded E1B protein of M(r) 55000 and the C-terminus of the cellular p53 protein. Analysis of the induction of damage by HSV and HCMV necessitates consideration of several factors, including the strain of virus used, the timing of infection, the type of cell used, and the multiplicity of infection. Both HSV strains 1 and 2 are cytotoxic, although the former seems to be more proficient at inducing damage. At early times post infection, HSV induces breaks and specific uncoiling of the centromeres of chromosomes 1, 9 and 16. This is followed at later times by a more complete severing of all of the chromosomes, termed pulverisation. Damage by HSV requires viral entry and de novo viral protein synthesis, with immediate early viral proteins responsible for the induction of breaks and uncoiling and early gene products (most likely nucleases) involved in the extensive pulverisation seen later. HCMV has been studied primarily in permissive human fibroblasts. Its ability to induce specific damage in chromosome 1 at two loci, 1q21 and 1q42, was only recently revealed as the cells must be in S-phase when they are infected for the breaks to be observed. In contrast to

  10. Site-specific PEGylation of lidamycin and its antitumor activity.

    PubMed

    Li, Liang; Shang, Boyang; Hu, Lei; Shao, Rongguang; Zhen, Yongsu

    2015-05-01

    In this study, N-terminal site-specific mono-PEGylation of the recombinant lidamycin apoprotein (rLDP) of lidamycin (LDM) was prepared using a polyethyleneglycol (PEG) derivative (M w 20 kDa) through a reactive terminal aldehyde group under weak acidic conditions (pH 5.5). The biochemical properties of mPEG-rLDP-AE, an enediyne-integrated conjugate, were analyzed by SDS-PAGE, RP-HPLC, SEC-HPLC and MALDI-TOF. Meanwhile, in vitro and in vivo antitumor activity of mPEG-rLDP-AE was evaluated by MTT assays and in xenograft model. The results indicated that mPEG-rLDP-AE showed significant antitumor activity both in vitro and in vivo. After PEGylation, mPEG-rLDP still retained the binding capability to the enediyne AE and presented the physicochemical characteristics similar to that of native LDP. It is of interest that the PEGylation did not diminish the antitumor efficacy of LDM, implying the possibility that this derivative may function as a payload to deliver novel tumor-targeted drugs. PMID:26579455

  11. Site-specific anticancer effects of dietary flavonoid quercetin.

    PubMed

    Sak, Katrin

    2014-01-01

    Food-derived flavonoid quercetin, widely distributed in onions, apples, and tea, is able to inhibit growth of various cancer cells indicating that this compound can be considered as a good candidate for anticancer therapy. Although the exact mechanism of this action is not thoroughly understood, behaving as antioxidant and/or prooxidant as well as modulating different intracellular signalling cascades may all play a certain role. Such inhibitory activity of quercetin has been shown to depend first of all on cell lines and cancer types; however, no comprehensive site-specific analysis of this effect has been published. In this review article, cytotoxicity constants of quercetin measured in various human malignant cell lines of different origin were compiled from literature and a clear cancer selective action was demonstrated. The most sensitive malignant sites for quercetin revealed to be cancers of blood, brain, lung, uterine, and salivary gland as well as melanoma whereas cytotoxic activity was higher in more aggressive cells compared to the slowly growing cells showing that the most harmful cells for the organism are probably targeted. More research is needed to overcome the issues of poor water solubility and relatively low bioavailability of quercetin as the major obstacles limiting its clinical use. PMID:24377461

  12. Monomeric site-specific nucleases for genome editing

    PubMed Central

    Kleinstiver, Benjamin P.; Wolfs, Jason M.; Kolaczyk, Tomasz; Roberts, Alanna K.; Hu, Sherry X.; Edgell, David R.

    2012-01-01

    Targeted manipulation of complex genomes often requires the introduction of a double-strand break at defined locations by site-specific DNA endonucleases. Here, we describe a monomeric nuclease domain derived from GIY-YIG homing endonucleases for genome-editing applications. Fusion of the GIY-YIG nuclease domain to three-member zinc-finger DNA binding domains generated chimeric GIY-zinc finger endonucleases (GIY-ZFEs). Significantly, the I-TevI-derived fusions (Tev-ZFEs) function in vitro as monomers to introduce a double-strand break, and discriminate in vitro and in bacterial and yeast assays against substrates lacking a preferred 5′-CNNNG-3′ cleavage motif. The Tev-ZFEs function to induce recombination in a yeast-based assay with activity on par with a homodimeric Zif268 zinc-finger nuclease. We also fused the I-TevI nuclease domain to a catalytically inactive LADGLIDADG homing endonuclease (LHE) scaffold. The monomeric Tev-LHEs are active in vivo and similarly discriminate against substrates lacking the 5′-CNNNG-3′ motif. The monomeric Tev-ZFEs and Tev-LHEs are distinct from the FokI-derived zinc-finger nuclease and TAL effector nuclease platforms as the GIY-YIG domain alleviates the requirement to design two nuclease fusions to target a given sequence, highlighting the diversity of nuclease domains with distinctive biochemical properties suitable for genome-editing applications. PMID:22566637

  13. Analysis of Chemokine Receptor Trafficking by Site-Specific Biotinylation

    PubMed Central

    Liebick, Marcel; Schläger, Christian; Oppermann, Martin

    2016-01-01

    Chemokine receptors undergo internalization and desensitization in response to ligand activation. Internalized receptors are either preferentially directed towards recycling pathways (e.g. CCR5) or sorted for proteasomal degradation (e.g. CXCR4). Here we describe a method for the analysis of receptor internalization and recycling based on specific Bir A-mediated biotinylation of an acceptor peptide coupled to the receptor, which allows a more detailed analysis of receptor trafficking compared to classical antibody-based detection methods. Studies on constitutive internalization of the chemokine receptors CXCR4 (12.1% ± 0.99% receptor internalization/h) and CCR5 (13.7% ± 0.68%/h) reveals modulation of these processes by inverse (TAK779; 10.9% ± 0.95%/h) or partial agonists (Met-CCL5; 15.6% ± 0.5%/h). These results suggest an actively driven internalization process. We also demonstrate the advantages of specific biotinylation compared to classical antibody detection during agonist-induced receptor internalization, which may be used for immunofluorescence analysis as well. Site-specific biotinylation may be applicable to studies on trafficking of transmembrane proteins, in general. PMID:27310579

  14. Site-specific group selection drives locally adapted group compositions.

    PubMed

    Pruitt, Jonathan N; Goodnight, Charles J

    2014-10-16

    Group selection may be defined as selection caused by the differential extinction or proliferation of groups. The socially polymorphic spider Anelosimus studiosus exhibits a behavioural polymorphism in which females exhibit either a 'docile' or 'aggressive' behavioural phenotype. Natural colonies are composed of a mixture of related docile and aggressive individuals, and populations differ in colonies' characteristic docile:aggressive ratios. Using experimentally constructed colonies of known composition, here we demonstrate that population-level divergence in docile:aggressive ratios is driven by site-specific selection at the group level--certain ratios yield high survivorship at some sites but not others. Our data also indicate that colonies responded to the risk of extinction: perturbed colonies tended to adjust their composition over two generations to match the ratio characteristic of their native site, thus promoting their long-term survival in their natal habitat. However, colonies of displaced individuals continued to shift their compositions towards mixtures that would have promoted their survival had they remained at their home sites, regardless of their contemporary environment. Thus, the regulatory mechanisms that colonies use to adjust their composition appear to be locally adapted. Our data provide experimental evidence of group selection driving collective traits in wild populations. PMID:25274310

  15. Site-specific basal body duplication in Chlamydomonas.

    PubMed

    O'Toole, Eileen T; Dutcher, Susan K

    2014-02-01

    Correct centriole/basal body positioning is required for numerous biological processes, yet how the cell establishes this positioning is poorly understood. Analysis of centriolar/basal body duplication provides a key to understanding basal body positioning and function. Chlamydomonas basal bodies contain structural features that enable specific triplet microtubules to be specified. Electron tomography of cultures enriched in mitotic cells allowed us to follow basal body duplication and identify a specific triplet at which duplication occurs. Probasal bodies elongate in prophase, assemble transitional fibers (TF) and are segregated with a mature basal body near the poles of the mitotic spindle. A ring of nine-singlet microtubules is initiated at metaphase, orthogonal to triplet eight. At telophase/cytokinesis, triplet microtubule blades assemble first at the distal end, rather than at the proximal cartwheel. The cartwheel undergoes significant changes in length during duplication, which provides further support for its scaffolding role. The uni1-1 mutant contains short basal bodies with reduced or absent TF and defective transition zones, suggesting that the UNI1 gene product is important for coordinated probasal body elongation and maturation. We suggest that this site-specific basal body duplication ensures the correct positioning of the basal body to generate landmarks for intracellular patterning in the next generation. PMID:24166861

  16. Micro-tattoo guided OCT imaging of site specific inflammation

    NASA Astrophysics Data System (ADS)

    Phillips, Kevin G.; Choudhury, Niloy; Samatham, Ravikant V.; Singh, Harvinder; Jacques, Steven L.

    2010-02-01

    Epithelial biologists studying human skin diseases such as cancer formation and psoriasis commonly utilize mouse models to characterize the interplay among cells and intracellular signal transduction pathways that result in programmed changes in gene expression and cellular behaviors. The information obtained from animal models is useful only when phenotypic presentations of disease recapitulate those observed in humans. Excision of tissues followed by histochemical analysis is currently the primary means of establishing the morphological presentation. Non invasive imaging of animal models provides an alternate means to characterize tissue morphology associated with the disease of interest in vivo. While useful, the ability to perform in vivo imaging at different time points in the same tissue location has been a challenge. This information is key to understanding site specific changes as the imaged tissue can now be extracted and analyzed for mRNA expression. We present a method employing a micro-tattoo to guide optical coherence tomography (OCT) imaging of ultraviolet induced inflammation over time in the same tissue locations.

  17. Site Specific Cleavage Mediated by MMPs Regulates Function of Agrin

    PubMed Central

    McFarlane, Ainsley; Xie, Irene; Overall, Christopher M.; Stetefeld, Jörg

    2012-01-01

    Background Agrin is the key inducer of postsynaptic differentiations at the neuromuscular junction. The multidomain heparan sulfate proteoglycan is mediating via its N-terminal segment the interaction with laminin, whereas the C-terminal portion is responsible for Dystroglycan binding and clustering of the Acetylcholine receptor. Matrix metalloproteinases (MMP) are known to play essential roles in matrix remodeling, degradation and regulation of extracellular signaling networks. Principal Findings Site-specific processing of Agrin provides key insight into regulatory effects of Matrix metalloproteinases (MMPs). Here, we present a detailed study of agrin processing by different MMPs together with a molecular understanding of binding and cleavage at both terminal fragments. The data suggest for a regulatory effect of MMP cleavage at particularly important functional sites of agrin. Cleave of agrin abolishes the agrin-laminin complex formation and the Acetylcholine receptor clustering at the neuromuscular junction. Conclusion/Significance Agrin is a target of specific MMP processing resulting in agrin subfragments with different regulatory activities. MMP processing is a powerful tool to regulate extracellular signaling networks. PMID:22984437

  18. Bone site-specific delivery of siRNA

    PubMed Central

    Liu, Xinli

    2016-01-01

    Abstract Small interfering RNAs (siRNA) have enormous potential as therapeutics to target and treat various bone disorders such as osteoporosis and cancer bone metastases. However, effective and specific delivery of siRNA therapeutics to bone and bone-specific cells in vivo is very challenging. To realize the full therapeutic potential of siRNA in treating bone disorders, a safe and efficient, tissue- and cell-specific delivery system must be developed. This review focuses on recent advances in bone site-specific delivery of siRNA at the tissue or cellular level. Bone-targeted nanoparticulate siRNA carriers and various bone-targeted moieties such as bisphosphonates, oligopeptides (Asp)8 and (AspSerSer)6, and aptamers are highlighted. Incorporation of these bone-seeking targeting moieties into siRNA carriers allows for recognition of different sub-tissue functional domains of bone and also specific cell types residing in bone tissue. It also provides a means for bone-formation surface-, bone-resorption surface-, or osteoblast-specific targeting and transportation of siRNA therapeutics. The discussion mainly focuses on systemic and local bone-specific delivery of siRNA in osteoporosis and bone metastasis preclinical models. PMID:26642236

  19. Site-Specific Seismic Site Response Model for the Waste Treatment Plant, Hanford, Washington

    SciTech Connect

    Rohay, Alan C.; Reidel, Steve P.

    2005-02-24

    This interim report documents the collection of site-specific geologic and geophysical data characterizing the Waste Treatment Plant site and the modeling of the site-specific structure response to earthquake ground motions.

  20. 75 FR 56526 - Environmental Management Site-Specific Advisory Board, Portsmouth

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-16

    ... Environmental Management Site-Specific Advisory Board, Portsmouth AGENCY: Department of Energy (DOE). ACTION... Environmental Management Site-Specific Advisory Board (EM SSAB), Portsmouth. The Federal Advisory Committee Act... areas of environmental restoration, waste management and related activities. Tentative Agenda...

  1. Site-specific hydrogen diffusion rates during clinopyroxene dehydration

    NASA Astrophysics Data System (ADS)

    Ferriss, Elizabeth; Plank, Terry; Walker, David

    2016-06-01

    The rate of hydrogen diffusion in clinopyroxene is relevant to interpreting hydrogen ("water") concentrations in xenoliths, phenocrysts, and clinopyroxene-hosted melt inclusions to provide insight into the deep-earth water cycle and volcanic explosivity. Here, we determine bulk and site-specific hydrogen diffusivities in two diopsides and an augite by heating initially homogeneous water-bearing samples in a 1-atm CO/CO2 gas-mixing furnace at 800-1000 °C and oxygen fugacity at the quartz-fayalite-magnetite buffer and observing H-loss profiles. The O-H stretching range between wavenumbers 3000 and 4000 cm-1 in FTIR spectra is resolved into 4-6 peaks, each of which is assumed to represent a distinct defect site for the hydrogen, to determine peak-specific diffusivities using our previously published whole-block method. For the diopside from the Kunlun Mts. in China, Arrhenius relations are reported for peaks at 3645, 3617, 3540, 3443, and 3355 cm-1 based on measurements at 816, 904, and 1000 °C. Bulk and site-specific diffusivities are determined for the same set of peaks at 904 °C for the second diopside (Jaipur). The augite (PMR-53) was a triangular thin slab, and hydrogen diffusivities were determined for bulk hydrogen and peaks at 3620, 3550, 3460, and 3355 cm-1 in the thickness direction at 800 °C. Bulk hydrogen diffusivity in the Jaipur diopside is consistent with previous work, and hydrogen diffusivity in augite PMR-53 is slightly lower than the fast direction diffusivities measured || [100] and [001]* in Jaipur diopside. Both diopsides show 1-2 orders of magnitude differences in the peaks-specific diffusivities, with the fastest diffusivities at 3450 cm-1 and the slowest at 3645 cm-1. However, the hydrogen diffusivities in Jaipur diopside are 2-4 orders of magnitude higher than those in Kunlun diopside for bulk hydrogen and all peaks. Thus, peak-specific differences cannot by themselves adequately explain the 5 orders of magnitude range in hydrogen

  2. Effect of site-specific modification on restriction endonucleases and DNA modification methyltransferases.

    PubMed Central

    McClelland, M; Nelson, M; Raschke, E

    1994-01-01

    Restriction endonucleases have site-specific interactions with DNA that can often be inhibited by site-specific DNA methylation and other site-specific DNA modifications. However, such inhibition cannot generally be predicted. The empirically acquired data on these effects are tabulated for over 320 restriction endonucleases. In addition, a table of known site-specific DNA modification methyltransferases and their specificities is presented along with EMBL database accession numbers for cloned genes. PMID:7937074

  3. STATIC AND KINETIC SITE-SPECIFIC PROTEIN-DNA PHOTOCROSSLINKING: ANALYSIS OF BACTERIAL TRANSCRIPTION INITIATION COMPLEXES

    PubMed Central

    Naryshkin, Nikolai; Druzhinin, Sergei; Revyakin, Andrei; Kim, Younggyu; Mekler, Vladimir; Ebright, Richard H.

    2009-01-01

    Static site-specific protein-DNA photocrosslinking permits identification of protein-DNA interactions within multiprotein-DNA complexes. Kinetic site-specific protein-DNA photocrosslinking--involving rapid-quench-flow mixing and pulsed-laser irradiation--permits elucidation of pathways and kinetics of formation of protein-DNA interactions within multiprotein-DNA complexes. We present detailed protocols for application of static and kinetic site-specific protein-DNA photocrosslinking to bacterial transcription initiation complexes. PMID:19378179

  4. Photoelectronic characterization of heterointerfaces.

    SciTech Connect

    Brumbach, Michael Todd

    2012-02-01

    In many devices such as solar cells, light emitting diodes, transistors, etc., the performance relies on the electronic structure at interfaces between materials within the device. The objective of this work was to perform robust characterization of hybrid (organic/inorganic) interfaces by tailoring the interfacial region for photoelectron spectroscopy. Self-assembled monolayers (SAM) were utilized to induce dipoles of various magnitudes at the interface. Additionally, SAMs of molecules with varying dipolar characteristics were mixed into spatially organized structures to systematically vary the apparent work function. Polymer thin films were characterized by depositing films of varying thicknesses on numerous substrates with and without interfacial modifications. Hard X-ray photoelectron spectroscopy (HAXPES) was performed to evaluate a buried interface between indium tin oxide (ITO), treated under various conditions, and poly(3-hexylthiophene) (P3HT). Conducting polymer films were found to be sufficiently conducting such that no significant charge redistribution in the polymer films was observed. Consequently, a further departure from uniform substrates was taken whereby electrically disconnected regions of the substrate presented ideally insulating interfacial contacts. In order to accomplish this novel strategy, interdigitated electrodes were used as the substrate. Conducting fingers of one half of the electrodes were electrically grounded while the other set of electrodes were electronically floating. This allowed for the evaluation of substrate charging on photoelectron spectra (SCOPES) in the presence of overlying semiconducting thin films. Such an experiment has never before been reported. This concept was developed out of the previous experiments on interfacial modification and thin film depositions and presents new opportunities for understanding chemical and electronic changes in a multitude of materials and interfaces.

  5. Site-specific control of silica mineralization on DNA using a designed peptide.

    PubMed

    Ozaki, Makoto; Nagai, Kazuma; Nishiyama, Hiroto; Tsuruoka, Takaaki; Fujii, Satoshi; Endoh, Tamaki; Imai, Takahito; Tomizaki, Kin-Ya; Usui, Kenji

    2016-03-01

    We developed a site-specific method for precipitating inorganic compounds using organic compounds, DNA, and designed peptides with peptide nucleic acids (PNAs). Such a system for site-specific precipitation represents a powerful tool for use in nanobiochemistry and materials chemistry. PMID:26690695

  6. 76 FR 38143 - Environmental Management Site-Specific Advisory Board, Savannah River Site

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-29

    ... Environmental Management Site-Specific Advisory Board, Savannah River Site AGENCY: Department of Energy, DOE... Site-Specific Advisory Board (EM SSAB), Savannah River Site. The Federal Advisory Committee Act (Pub. L... CONTACT: Gerri Flemming, Office of External Affairs, Department of Energy, Savannah River...

  7. FLP recombinase-mediated site-specific recombination in silkworm, Bombyx mori

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A comprehensive understanding of gene function and the production of site-specific genetically modified mutants are two major goals of genetic engineering in the post-genomic era. Although site-specific recombination systems have been powerful tools for genome manipulation of many organisms, they h...

  8. 75 FR 19630 - Environmental Management Site-Specific Advisory Board Charter Renewal

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-15

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board Charter Renewal Pursuant to Section 14(a)(2)(A) of the... renewal of the Environmental Management Site- Specific Advisory Board has been determined to be...

  9. A cyclopropene-modified nucleotide for site-specific RNA labeling using genetic alphabet expansion transcription.

    PubMed

    Eggert, F; Kath-Schorr, S

    2016-06-01

    Site-specific RNA modification with methyl cyclopropene moieties is performed by T7 in vitro transcription. An existing unnatural base is functionalized with a cyclopropene moiety and used in transcription reactions to produce site-specifically cyclopropene-modified RNA molecules. The posttranscriptional inverse electron demand Diels-Alder cycloaddition reaction with a selected tetrazine-fluorophore conjugate is demonstrated. PMID:27181840

  10. 7 CFR 1726.404 - Non-site specific construction contract closeout.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... UTILITIES SERVICE, DEPARTMENT OF AGRICULTURE ELECTRIC SYSTEM CONSTRUCTION POLICIES AND PROCEDURES Contract Closeout § 1726.404 Non-site specific construction contract closeout. This section is applicable to... 7 Agriculture 11 2010-01-01 2010-01-01 false Non-site specific construction contract...

  11. 76 FR 28218 - Environmental Management Site-Specific Advisory Board, Hanford

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-16

    ... Environmental Management Site-Specific Advisory Board, Hanford AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific...: Purpose of the Board: The purpose of the Board is to make recommendations to DOE-EM and site management...

  12. 75 FR 48662 - Environmental Management Site-Specific Advisory Board, Nevada

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-11

    ... Environmental Management Site-Specific Advisory Board, Nevada AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific Advisory Board (EM SSAB), Nevada Test Site. The Federal Advisory Committee Act (Pub. L. 92-463, 86...

  13. 77 FR 16542 - Environmental Management Site-Specific Advisory Board, Hanford

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-21

    ... Environmental Management Site-Specific Advisory Board, Hanford AGENCY: Department of Energy. ACTION: Notice of Open Meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific...: Purpose of the Board: The purpose of the Board is to make recommendations to DOE-EM and site management...

  14. 77 FR 75627 - Environmental Management Site-Specific Advisory Board, Nevada

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-21

    ... Environmental Management Site-Specific Advisory Board, Nevada AGENCY: Department of Energy. ACTION: Notice of Open Meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific Advisory Board (EM SSAB), Nevada. The Federal Advisory Committee Act (Pub. L. 92-463, 86 Stat....

  15. 75 FR 6370 - Environmental Management Site-Specific Advisory Board, Nevada

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-09

    ... Environmental Management Site-Specific Advisory Board, Nevada AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific...: Wednesday, March 10, 2010, 5 p.m. ADDRESSES: Centennial Hills Library, 6711 North Buffalo Drive, Las...

  16. 77 FR 45345 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-31

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  17. 78 FR 3890 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-17

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  18. 76 FR 4644 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-26

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  19. 77 FR 23470 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-19

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  20. 77 FR 9219 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-16

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of Energy,...

  1. 76 FR 78908 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-20

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  2. 76 FR 65190 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-20

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  3. 76 FR 9572 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-18

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  4. 77 FR 29996 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-21

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  5. 76 FR 17637 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-30

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  6. 75 FR 24685 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-05

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  7. 75 FR 57462 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-21

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  8. 78 FR 63171 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation; Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-23

    ... Management Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation; Meeting AGENCY: Department...

  9. 76 FR 52944 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-24

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  10. 78 FR 75552 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-12

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  11. 78 FR 44942 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-25

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  12. 75 FR 82001 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-29

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  13. 76 FR 29732 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-23

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  14. 76 FR 36101 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-21

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  15. 75 FR 13268 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-19

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  16. 75 FR 65466 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-25

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  17. 77 FR 18243 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-27

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  18. 75 FR 27998 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-19

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  19. 75 FR 3455 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-21

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  20. 76 FR 59393 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-26

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  1. 78 FR 23241 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-18

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  2. 78 FR 12746 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-25

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  3. 77 FR 2714 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-19

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  4. 75 FR 51027 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-18

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  5. 75 FR 43518 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-26

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  6. 75 FR 71424 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-23

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  7. 77 FR 74836 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-18

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  8. 77 FR 58364 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-20

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  9. 75 FR 7576 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-22

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  10. 76 FR 28759 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-18

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  11. 75 FR 35447 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-22

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  12. 76 FR 22388 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-21

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  13. 76 FR 51361 - Environmental Management Site-Specific Advisory Board, Northern New Mexico

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-18

    ... Environmental Management Site-Specific Advisory Board, Northern New Mexico AGENCY: Department of Energy (DoE... Site-Specific Advisory Board (EM SSAB), Northern New Mexico. The Federal Advisory Committee Act (Pub. L... Center, 1508 Paseo de Pueblo Sur, Taos, New Mexico. FOR FURTHER INFORMATION CONTACT: Menice...

  14. 76 FR 36101 - Environmental Management Site-Specific Advisory Board, Northern New Mexico; Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-21

    ... Environmental Management Site-Specific Advisory Board, Northern New Mexico; Meeting AGENCY: Department of Energy... Site-Specific Advisory Board (EM SSAB), Northern New Mexico. The Federal Advisory Committee Act (Pub. L... Drive, Los Alamos, New Mexico. FOR FURTHER INFORMATION CONTACT: Menice Santistevan, Northern New...

  15. 78 FR 63171 - Environmental Management Site-Specific Advisory Board, Northern New Mexico; Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-23

    ... Environmental Management Site-Specific Advisory Board, Northern New Mexico; Meeting AGENCY: Department of Energy... Site-Specific Advisory Board (EM SSAB), Northern New Mexico. The Federal Advisory Committee Act (Pub. L... New Mexico 291, San Juan Pueblo, New Mexico 87566. FOR FURTHER INFORMATION CONTACT: Menice...

  16. On-the-go nitrogen sensing and fertilizer control for site-specific crop management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In-field site-specific nitrogen (N) management increases crop yield, reduces N application to minimize the risk of nitrate contamination of ground water, and thus reduces farming cost. Real-time N sensing and fertilization is required for efficient N management. An ‘on-the-go’ site-specific N manage...

  17. 76 FR 19003 - Land Disposal Restrictions: Nevada and California; Site Specific Treatment Variances for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-06

    ...: Proposed rule. SUMMARY: EPA is proposing to issue both a site-specific treatment variance to U.S. Ecology... proposes to issue both a site-specific treatment variance to U.S. Ecology Nevada (USEN) located in Beatty... section of this document. II. Does this action apply to me? This proposal applies only to U. S....

  18. 76 FR 80354 - Environmental Management Site-Specific Advisory Board, Nevada

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-23

    ... Environmental Management Site-Specific Advisory Board, Nevada AGENCY: Department of Energy. ACTION: Notice of Open Meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... management in the areas of environmental restoration, waste management, and related activities....

  19. 76 FR 17118 - Environmental Management Site-Specific Advisory Board Chairs

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-28

    ... Environmental Management Site-Specific Advisory Board Chairs AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... Board is to make recommendations to DOE-EM and site management in the areas of environmental...

  20. 78 FR 61348 - Environmental Management Site-Specific Advisory Board, Portsmouth

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-03

    ..., 2013 of the Environmental Management Site-Specific Advisory Board, Portsmouth (78 FR 56871). This... Environmental Management Site-Specific Advisory Board, Portsmouth AGENCY: Department of Energy. ACTION: Notice of Cancellation of Open Meeting. SUMMARY: On September 16, 2013, in FR Doc. 2013-22453, on page...

  1. 78 FR 4139 - Environmental Management Site-Specific Advisory Board, Hanford

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-18

    ... Environmental Management Site-Specific Advisory Board, Hanford AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... and site management in the areas of environmental restoration, waste management, and...

  2. 75 FR 17701 - Environmental Management Site-Specific Advisory Board Chairs

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-07

    ... Environmental Management Site-Specific Advisory Board Chairs AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... environmental restoration, waste management, and related activities. Tentative Agenda Topics: Wednesday,...

  3. 78 FR 49738 - Environmental Management Site-Specific Advisory Board, Hanford

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-15

    ... Environmental Management Site-Specific Advisory Board, Hanford AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... and site management in the areas of environmental restoration, waste management, and...

  4. 78 FR 20311 - Environmental Management Site-Specific Advisory Board Chairs

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-04

    ... Environmental Management Site-Specific Advisory Board Chairs AGENCY: Department of Energy. ACTION: Notice of Open Webinar. SUMMARY: This notice announces a webinar of the Environmental Management Site-Specific... recommendations to DOE-EM and site management in the areas of environmental restoration, waste management,...

  5. 77 FR 39234 - Environmental Management Site-Specific Advisory Board, Nevada

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-02

    ... Environmental Management Site-Specific Advisory Board, Nevada AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... and site management in the areas of environmental restoration, waste management, and...

  6. 76 FR 5365 - Environmental Management Site-Specific Advisory Board, Nevada

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-31

    ... Environmental Management Site-Specific Advisory Board, Nevada AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... and site management in the areas of environmental restoration, waste management, and...

  7. 76 FR 63613 - Environmental Management Site-Specific Advisory Board, Hanford

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-13

    ... Environmental Management Site-Specific Advisory Board, Hanford AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... management in the areas of environmental restoration, waste management, and related activities....

  8. 75 FR 13269 - Environmental Management Site-Specific Advisory Board, Hanford

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-19

    ... Environmental Management Site-Specific Advisory Board, Hanford AGENCY: Department of Energy. ACTION: Notice of Open Meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... management in the areas of environmental restoration, waste management, and related activities....

  9. 77 FR 28368 - Environmental Management Site-Specific Advisory Board, Hanford

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-14

    ... Environmental Management Site-Specific Advisory Board, Hanford AGENCY: Department of Energy. ACTION: Notice of Open Meeting. SUMMARY: This notice announces a meeting of the Environmental ] Management Site-Specific... management in the areas of environmental restoration, waste management, and related activities....

  10. 78 FR 26635 - Environmental Management Site-Specific Advisory Board, Paducah

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-07

    ... Environmental Management Site-Specific Advisory Board, Paducah AGENCY: Department of Energy. ACTION: Notice of... of open meeting announcing a meeting on May 16, 2013 of the Environmental Management Site-Specific Advisory Board, Paducah (78 FR 25064). This document makes a correction to that notice. FOR...

  11. 75 FR 2859 - Environmental Management Site-Specific Advisory Board, Hanford

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-19

    ... Environmental Management Site-Specific Advisory Board, Hanford AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... management in the areas of environmental restoration, waste management, and related activities....

  12. 77 FR 64112 - Environmental Management Site-Specific Advisory Board, Hanford

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-18

    ... Environmental Management Site-Specific Advisory Board, Hanford AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... management in the areas of environmental restoration, waste management, and related activities....

  13. 78 FR 68431 - Environmental Management Site-Specific Advisory Board, Hanford

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-14

    ... Environmental Management Site-Specific Advisory Board, Hanford AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... and site management in the areas of environmental restoration, waste management, and...

  14. 77 FR 55813 - Environmental Management Site-Specific Advisory Board Chairs

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-11

    ... Environmental Management Site-Specific Advisory Board Chairs AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... Board is to make recommendations to DOE-EM and site management in the areas of environmental...

  15. 78 FR 59012 - Environmental Management Site-Specific Advisory Board Chairs

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-25

    ... Environmental Management Site-Specific Advisory Board Chairs AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... environmental restoration, waste management, and related activities. Tentative Agenda Topics: Wednesday,...

  16. 76 FR 50204 - Environmental Management Site-Specific Advisory Board, Nevada

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-12

    ... Environmental Management Site-Specific Advisory Board, Nevada AGENCY: Department of Energy. ACTION: Notice of... (EIS) Committee of the Environmental Management Site- Specific Advisory Board (EM SSAB), Nevada. The... environmental restoration, waste management, and related activities. Purpose of the Committee: The purpose...

  17. 75 FR 51450 - Environmental Management Site-Specific Advisory Board Chairs

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-20

    ... Environmental Management Site-Specific Advisory Board Chairs AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... the Board is to make recommendations ] to DOE-EM and site management in the areas of...

  18. 78 FR 64208 - Environmental Management Site-Specific Advisory Board Chairs

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-28

    ... Environmental Management Site-Specific Advisory Board Chairs AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... environmental restoration, waste management, and related activities. Tentative Agenda Topics: Tuesday,...

  19. 77 FR 4027 - Environmental Management Site-Specific Advisory Board, Nevada

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-26

    ... Environmental Management Site-Specific Advisory Board, Nevada AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... and site management in the areas of environmental restoration, waste management, and...

  20. 78 FR 64932 - Environmental Management Site-Specific Advisory Board, Nevada

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-30

    ... Environmental Management Site-Specific Advisory Board, Nevada AGENCY: Department of Energy. ACTION: Notice of Open Meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... recommendations to DOE-EM and site management in the areas of environmental restoration, waste management,...

  1. 75 FR 6018 - Environmental Management Site-Specific Advisory Board, Hanford

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-05

    ... Environmental Management Site-Specific Advisory Board, Hanford AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... the Board is to make recommendations to DOE-EM and site management in the areas of...

  2. 77 FR 12044 - Environmental Management Site-Specific Advisory Board, Nevada

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-28

    ... Environmental Management Site-Specific Advisory Board, Nevada AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... recommendations to DOE-EM and site management in the areas of environmental restoration, waste management,...

  3. 75 FR 8050 - Environmental Management Site-Specific Advisory Board, Hanford

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-23

    ... Environmental Management Site-Specific Advisory Board, Hanford AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... and site management in the areas of environmental restoration, waste management, and...

  4. 76 FR 20651 - Environmental Management Site-Specific Advisory Board Chairs

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-13

    ... Environmental Management Site-Specific Advisory Board Chairs (76 FR 17118). This notice announces the... Environmental Management Site-Specific Advisory Board Chairs AGENCY: Department of Energy. ACTION: Notice of cancellation of open meeting. SUMMARY: On March 28, 2011, in FR Doc. 2011-7243, on page 17118, the...

  5. 78 FR 23760 - Environmental Management Site-Specific Advisory Board, Nevada

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-22

    ... Environmental Management Site-Specific Advisory Board, Nevada AGENCY: Department of Energy. ACTION: Notice of Open Meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... and site management in the areas of environmental restoration, waste management, and...

  6. 76 FR 4645 - Environmental Management Site-Specific Advisory Board, Hanford

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-26

    ... Environmental Management Site-Specific Advisory Board, Hanford AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... management in the areas of environmental restoration, waste management, and related activities....

  7. 78 FR 53135 - Environmental Management Site-Specific Advisory Board, Nevada

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-28

    ... Environmental Management Site-Specific Advisory Board, Nevada AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... recommendations to DOE-EM and site management in the areas of environmental restoration, waste management,...

  8. 75 FR 82004 - Environmental Management Site-Specific Advisory Board, Nevada

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-29

    ... Environmental Management Site-Specific Advisory Board, Nevada AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... and site management in the areas of environmental restoration, waste management, and...

  9. 75 FR 65310 - Environmental Management Site-Specific Advisory Board, Nevada

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-22

    ... Environmental Management Site-Specific Advisory Board, Nevada AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... and site management in the areas of environmental restoration, waste management, and...

  10. 76 FR 52944 - Environmental Management Site-Specific Advisory Board, Nevada

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-24

    ... Environmental Management Site-Specific Advisory Board, Nevada AGENCY: Department of Energy. ACTION: Notice of... (EIS) Committee of the Environmental Management Site- Specific Advisory Board (EM SSAB), Nevada. The... environmental restoration, waste management, and related activities. Purpose of the Committee: The purpose...

  11. 78 FR 28207 - Environmental Management Site-Specific Advisory Board, Hanford

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-14

    ... Environmental Management Site-Specific Advisory Board, Hanford AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... and site management in the areas of environmental restoration, waste management, and...

  12. 76 FR 55370 - Environmental Management Site-Specific Advisory Board, Nevada

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-07

    ... Environmental Management Site-Specific Advisory Board, Nevada AGENCY: Department of Energy. ACTION: Notice of... (EIS) Committee of the Environmental Management Site- Specific Advisory Board (EM SSAB), Nevada. The... environmental restoration, waste management, and related activities. Purpose of the Committee: The purpose...

  13. 77 FR 16021 - Environmental Management Site-Specific Advisory Board, Nevada

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-19

    ... Environmental Management Site-Specific Advisory Board, Nevada AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... recommendations to DOE-EM and site management in the areas of environmental restoration, waste management,...

  14. 40 CFR 62.14620 - What site-specific documentation is required?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 8 2011-07-01 2011-07-01 false What site-specific documentation is... POLLUTANTS Federal Plan Requirements for Commercial and Industrial Solid Waste Incineration Units That... site-specific documentation is required? (a) Documentation must be available at the facility...

  15. 40 CFR 60.2095 - What site-specific documentation is required?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Commercial and Industrial Solid Waste Incineration Units for Which Construction Is Commenced After November... 40 Protection of Environment 6 2011-07-01 2011-07-01 false What site-specific documentation is... Training and Qualification § 60.2095 What site-specific documentation is required? (a) Documentation...

  16. 29 CFR 1926.752 - Site layout, site-specific erection plan and construction sequence.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Site layout, site-specific erection plan and construction... Steel Erection § 1926.752 Site layout, site-specific erection plan and construction sequence. (a... strength or sufficient strength to support the loads imposed during steel erection. (c) Site layout....

  17. 76 FR 53888 - Environmental Management Site-Specific Advisory Board, Idaho National Laboratory

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-30

    ... Environmental Management Site-Specific Advisory Board, Idaho National Laboratory AGENCY: Department of Energy... Site-Specific Advisory Board (EM SSAB), Idaho National Laboratory. The Federal Advisory Committee Act... Participation: The EM SSAB, Idaho National Laboratory, welcomes the attendance of the public at its...

  18. 75 FR 56527 - Environmental Management Site-Specific Advisory Board, Idaho National Laboratory

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-16

    ... Environmental Management Site-Specific Advisory Board, Idaho National Laboratory AGENCY: Department of Energy... Site-Specific Advisory Board (EM SSAB), Idaho National Laboratory. The Federal Advisory Committee Act.... Overview Legacy Management--Long-Term Land Use at Idaho National Laboratory. Integrated Waste...

  19. 78 FR 58294 - Environmental Management Site-Specific Advisory Board, Idaho National Laboratory

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-23

    ... Environmental Management Site-Specific Advisory Board, Idaho National Laboratory AGENCY: Department of Energy... Site-Specific Advisory Board (EM SSAB), Idaho National Laboratory. The Federal Advisory Committee Act... SSAB, Idaho National Laboratory, welcomes the attendance of the public at its advisory...

  20. 77 FR 76475 - Environmental Management Site-Specific Advisory Board, Idaho National Laboratory

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-28

    ... Environmental Management Site-Specific Advisory Board, Idaho National Laboratory AGENCY: Department of Energy... Site-Specific Advisory Board (EM SSAB), Idaho National Laboratory. The Federal Advisory Committee Act... Laboratory/ICP Public Involvement/ Communications Sodium Bearing Waste Treatment Plant Update ICP End...

  1. 75 FR 9590 - Environmental Management Site-Specific Advisory Board, Idaho National Laboratory

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-03

    ... Environmental Management Site-Specific Advisory Board, Idaho National Laboratory AGENCY: Department of Energy... Site-Specific Advisory Board (EM SSAB), Idaho National Laboratory. The Federal Advisory Committee Act... Laboratory, welcomes the attendance of the public at its advisory committee meetings and will make...

  2. 75 FR 346 - Environmental Management Site-Specific Advisory Board, Idaho National Laboratory

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-05

    ... Environmental Management Site-Specific Advisory Board, Idaho National Laboratory AGENCY: Department of Energy... Site-Specific Advisory Board (EM SSAB), Idaho National Laboratory. The Federal Advisory Committee Act... Decision. Public Participation: The EM SSAB, Idaho National Laboratory, welcomes the attendance of...

  3. 77 FR 38276 - Environmental Management Site-Specific Advisory Board, Idaho National Laboratory

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-27

    ... Environmental Management Site-Specific Advisory Board, Idaho National Laboratory AGENCY: Department of Energy... Management Site-Specific Advisory Board (EM SSAB), Idaho National Laboratory. The Federal Advisory Committee... Center Status Public Participation: The EM SSAB, Idaho National Laboratory, welcomes the attendance...

  4. 76 FR 25682 - Environmental Management Site-Specific Advisory Board, Idaho National Laboratory

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-05

    ... Environmental Management Site-Specific Advisory Board, Idaho National Laboratory AGENCY: Department of Energy... Site-Specific Advisory Board (EM SSAB), Idaho National ] Laboratory. The Federal Advisory Committee Act... National Laboratory, welcomes the attendance of the public at its advisory committee meetings and will...

  5. 75 FR 39008 - Environmental Management Site-Specific Advisory Board, Idaho National Laboratory

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-07

    ... Environmental Management Site-Specific Advisory Board, Idaho National Laboratory AGENCY: Department of Energy... Site-Specific Advisory Board (EM SSAB), Idaho National Laboratory. The Federal Advisory Committee Act... Laboratory, welcomes the attendance of the public at its advisory committee meetings and will make...

  6. 78 FR 12747 - Environmental Management Site-Specific Advisory Board, Idaho National Laboratory

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-25

    ... Environmental Management Site-Specific Advisory Board, Idaho National Laboratory AGENCY: Department of Energy... Site-Specific Advisory Board (EM SSAB), Idaho National Laboratory. The Federal Advisory Committee Act... Participation: The EM SSAB, Idaho National Laboratory, welcomes the attendance of the public at its...

  7. 76 FR 39080 - Environmental Management Site-Specific Advisory Board, Idaho National Laboratory

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-05

    ... Environmental Management Site-Specific Advisory Board, Idaho National Laboratory AGENCY: Department of Energy... Site-Specific Advisory Board (EM SSAB), Idaho National Laboratory. The Federal Advisory Committee Act... National Laboratory (INL) 101. INL EM Budget. Calcine Path Forward. Advanced Mixed Waste Treatment...

  8. 77 FR 53192 - Environmental Management Site-Specific Advisory Board, Idaho National Laboratory

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-31

    ... Environmental Management Site-Specific Advisory Board, Idaho National Laboratory AGENCY: Department of Energy... Site-Specific Advisory Board (EM SSAB), Idaho National Laboratory. The Federal Advisory Committee Act... Closeout Process Public Participation: The EM SSAB, Idaho National Laboratory, welcomes the attendance...

  9. 75 FR 24685 - Environmental Management Site-Specific Advisory Board, Idaho National Laboratory

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-05

    ... Environmental Management Site-Specific Advisory Board, Idaho National Laboratory AGENCY: Department of Energy... Site-Specific Advisory Board (EM SSAB), Idaho National Laboratory. The Federal Advisory Committee Act... to Cleanup Idaho National Laboratory Site Wide Review--CERCLA Long-Term Ecological Program...

  10. 76 FR 68179 - Environmental Management Site-Specific Advisory Board, Idaho National Laboratory

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-03

    ... Management Site-Specific Advisory Board, Idaho National Laboratory (76 FR 66917). This document makes a... page at: http://inlcab.energy.gov/ . Correction In the Federal Register of October 28, 2011, in FR Doc... Environmental Management Site-Specific Advisory Board, Idaho National Laboratory AGENCY: Department of...

  11. 77 FR 65374 - Environmental Management Site-Specific Advisory Board, Idaho National Laboratory

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-26

    ... Environmental Management Site-Specific Advisory Board, Idaho National Laboratory AGENCY: Department of Energy... Site-Specific Advisory Board (EM SSAB), Idaho National Laboratory. The Federal Advisory Committee Act... National Laboratory/ICP Public Involvement/ Communications Public Participation: The EM SSAB,...

  12. 75 FR 82004 - Environmental Management Site-Specific Advisory Board, Idaho National Laboratory

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-29

    ... Environmental Management Site-Specific Advisory Board, Idaho National Laboratory AGENCY: Department of Energy... Site-Specific Advisory Board (EM SSAB), Idaho National Laboratory. The Federal Advisory Committee Act... Participation: The EM SSAB, Idaho National Laboratory, welcomes the attendance of the public at its...

  13. 76 FR 10018 - Environmental Management Site-Specific Advisory Board, Idaho National Laboratory

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-23

    ... Environmental Management Site-Specific Advisory Board, Idaho National Laboratory AGENCY: Department of Energy... Site-Specific Advisory Board (EM SSAB), Idaho National Laboratory. The Federal Advisory Committee Act... Public Participation: The EM SSAB, Idaho National Laboratory, welcomes the attendance of the public...

  14. 77 FR 10485 - Environmental Management Site-Specific Advisory Board, Idaho National Laboratory

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-22

    ... Environmental Management Site-Specific Advisory Board, Idaho National Laboratory AGENCY: Department of Energy... Site-Specific Advisory Board (EM SSAB), Idaho National Laboratory. The Federal Advisory Committee Act...--Future Work Plan Public Participation: The EM SSAB, Idaho National Laboratory, welcomes the attendance...

  15. 76 FR 66917 - Environmental Management Site-Specific Advisory Board, Idaho National Laboratory

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-28

    ... Environmental Management Site-Specific Advisory Board, Idaho National Laboratory AGENCY: Department of Energy... Site-Specific Advisory Board (EM SSAB), Idaho National Laboratory. The Federal Advisory Committee Act... Environmental Assessment Public Participation: The EM SSAB, Idaho National Laboratory, welcomes the...

  16. 78 FR 30910 - Environmental Management Site-Specific Advisory Board, Idaho National Laboratory

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-23

    ... Environmental Management Site-Specific Advisory Board, Idaho National Laboratory AGENCY: Department of Energy... Site-Specific Advisory Board (EM SSAB), Idaho National Laboratory. The Federal Advisory Committee Act...: The EM SSAB, Idaho National Laboratory, welcomes the attendance of the public at its...

  17. 40 CFR 60.2095 - What site-specific documentation is required?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 7 2013-07-01 2013-07-01 false What site-specific documentation is... site-specific documentation is required? (a) Documentation must be available at the facility and....2055 through 60.2065. (9) Procedures for handling ash. (10) A list of the wastes burned during...

  18. 40 CFR 62.14620 - What site-specific documentation is required?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 9 2014-07-01 2014-07-01 false What site-specific documentation is... site-specific documentation is required? (a) Documentation must be available at the facility and....14580 through 62.14590. (9) Procedures for handling ash. (10) A list of the wastes burned during...

  19. 40 CFR 60.2095 - What site-specific documentation is required?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 7 2014-07-01 2014-07-01 false What site-specific documentation is... site-specific documentation is required? (a) Documentation must be available at the facility and....2055 through 60.2065. (9) Procedures for handling ash. (10) A list of the wastes burned during...

  20. 40 CFR 62.14620 - What site-specific documentation is required?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 9 2012-07-01 2012-07-01 false What site-specific documentation is... site-specific documentation is required? (a) Documentation must be available at the facility and....14580 through 62.14590. (9) Procedures for handling ash. (10) A list of the wastes burned during...

  1. 40 CFR 60.2095 - What site-specific documentation is required?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 7 2012-07-01 2012-07-01 false What site-specific documentation is... Training and Qualification § 60.2095 What site-specific documentation is required? (a) Documentation must... required under §§ 60.2055 through 60.2065. (9) Procedures for handling ash. (10) A list of the...

  2. 40 CFR 62.14620 - What site-specific documentation is required?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 9 2013-07-01 2013-07-01 false What site-specific documentation is... site-specific documentation is required? (a) Documentation must be available at the facility and....14580 through 62.14590. (9) Procedures for handling ash. (10) A list of the wastes burned during...

  3. 75 FR 64718 - Environmental Management Site-Specific Advisory Board, Hanford

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-20

    ... Environmental Management Site-Specific Advisory Board, Hanford AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... the areas of environmental restoration, waste management, and related activities. Tentative...

  4. 77 FR 26273 - Environmental Management Site-Specific Advisory Board, Northern New Mexico

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-03

    ... Environmental Management Site-Specific Advisory Board, Northern New Mexico AGENCY: Department of Energy, DoE... Site-Specific Advisory Board (EM SSAB), Northern New Mexico. The Federal Advisory Committee Act (Pub. L... New Mexico Citizens' Advisory Board (NNMCAB), 94 Cities of Gold Road, Santa Fe, NM 87506. Phone...

  5. 75 FR 24686 - Environmental Management Site-Specific Advisory Board, Northern New Mexico

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-05

    ... Environmental Management Site-Specific Advisory Board, Northern New Mexico AGENCY: Department of Energy. ACTION... Management Site-Specific Advisory Board (EM SSAB), Northern New Mexico. The Federal Advisory Committee Act...: Ohkay Owingeh Conference Center, North Taos Highway 68, San Juan Pueblo, New Mexico 87566. FOR...

  6. 40 CFR 170.232 - Knowledge of labeling and site-specific information.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Knowledge of labeling and site-specific information. 170.232 Section 170.232 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS WORKER PROTECTION STANDARD Standard for Pesticide Handlers § 170.232 Knowledge of labeling and site-specific...

  7. 76 FR 51362 - Environmental Management Site-Specific Advisory Board, Nevada

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-18

    ... activities. Tentative Agenda 1. Update--Site-Specific Environmental Impact Statement Committee. 2. Update... advance of the meeting at the phone number listed above. Written statements may be filed with the Board... Environmental Management Site-Specific Advisory Board, Nevada AGENCY: Department of Energy. ACTION: Notice...

  8. SITE-SPECIFIC RECOMBINATION FOR PLANT GENETIC ENGINEERING: STRATEGY FOR AGRO-MEDIATED GENE STACKING

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The precise rearrangement of DNA in planta can be achieved through site-specific recombination. For the past decade and a half, laboratory experiments have shown that site-specific recombination can delete genomic DNA, regulate gene expression, recombine chromosomes, and target new DNA into designat...

  9. Ligand binding and proton exchange dynamics in site-specific mutants of human myoglobin

    SciTech Connect

    Lambright, D.G.

    1992-01-01

    Site specific mutagenesis was used to make substitutions of four residues in the distal heme pocket of human myoglobin: Val68, His64, Lys45, and Asp60. Strongly diffracting crystals of the conservative mutation K45R in the met aquo form were grown in the trigonal space group P3[sub 2]21 and the X-ray crystal structure determined at 1.6 [angstrom] resolution. The overall structure is similar to that of sperm whale met aquo myoglobin. Several of the mutant proteins were characterized by 2-D NMR spectroscopy. The NMR data suggest the structural changes are localized to the region of the mutation. The dynamics of ligand binding to myoglobin mutants were studied by transient absorption spectroscopy following photolysis of the CO complexes. Transient absorption kinetics and spectra on the ns to ms timescale were measured in aqueous solution from 280 K to 310 K and in 75% glycerol: water from 250 K to 310 K. Two significant basis spectra were obtained from singular value decomposition of the matrix of time dependent spectra. The information was used to obtain approximations for the extent of ligand rebinding and the kinetics of conformational relaxation. Except for K45R, substitutions at Lys45 or Asp60 produce changes in the kinetics for ligand rebinding. Replacement of Lys45 with Arg increases the rate of ligand rebinding from the protein matrix by a factor of 2, but does not alter the rates for ligand escape or entry into the protein or the dynamics of the conformational relaxation. Substitutions at His64 and Val68 influence the kinetics of ligand rebinding and the dynamics of conformational relaxation. The results do not support the hypothesis that ligand migration between the heme pocket and solvent is determined solely by fluctuations of Arg45 and His64 between open and closed conformations of the heme pocket but can be rationalized if ligand diffusion through the protein matrix involves multiple competing pathways.

  10. [Advances in the study of site-specific antibody-drug conjugates].

    PubMed

    Sun, Yu; Huang, Rong; Sun, Bai-wang

    2015-10-01

    Antibody drug conjugates (ADCs) are an emerging class of targeted therapeutics with the potential to improve therapeutic index over the traditional chemotherapy. However, it is difficult to control the site and stoichiometry of conjugation in mAb, typically resulting in heterogeneous mixtures of ADCs that are difficult to optimize. New methods for site-specific drug attachment allow development of more homogeneous conjugates and control of the site of drug attachment. In this article, the new literature on development of ADCs and site-specific ADCs is reviewed. In addition, we summarized the various strategies in production of site-specific ADCs. PMID:26837166