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Sample records for traps ii structures

  1. Charged particle traps II applications

    CERN Document Server

    Werth, Günther; Major, Fouad G

    2009-01-01

    This, the second volume of Charged Particle Traps, is devoted to applications, complementing the first volume’s comprehensive treatment of the theory and practice of charged particle traps, their many variants and refinements. In recent years, applications of far reaching importance have emerged ranging from the ultra-precise mass determinations of elementary particles and their antiparticles and short-lived isotopes, to high-resolution Zeeman spectroscopy on multiply-charged ions, to microwave and optical spectroscopy, some involving "forbidden" transitions from metastable states of such high resolution that optical frequency standards are realized by locking lasers to them. Further the potential application of trapped ions to quantum computing is explored, based on the extraordinary quantum state coherence made possible by the particle isolation. Consideration is given to the Paul and Penning traps as potential quantum information processors.

  2. First Test of a Radionuclide Trap at KNK II

    International Nuclear Information System (INIS)

    Stamm, H.-H.; Hanke, H.-D.; Clauss, H.

    1984-03-01

    The first test of an experimental radionuclide trap was performed at KNK II. The aim was to remove some Zn-65 and Mn-54 from the primary sodium. The 2.3 l trap was filled with stainless steel and nickel pallrings of different sizes and was operated for 100 hours at 312 ''0C and a flow rate of 1.6 m''3 Na/h. On the Ni samples 110 times the amount of Mn-54 and 440 times the amount of Zn-65 have been sorbed compared to stainless steel pallrings of the same size. The activity sorbed was proportional to the surface area

  3. Oxidative degradation of the organometallic iron(II) complex [Fe{bis[3-(pyridin-2-yl)-1H-imidazol-1-yl]methane}(MeCN)(PMe3)](PF6)2: structure of the ligand decomposition product trapped via coordination to iron(II).

    Science.gov (United States)

    Haslinger, Stefan; Pöthig, Alexander; Cokoja, Mirza; Kühn, Fritz E

    2015-12-01

    Iron is of interest as a catalyst because of its established use in the Haber-Bosch process and because of its high abundance and low toxicity. Nitrogen-heterocyclic carbenes (NHC) are important ligands in homogeneous catalysis and iron-NHC complexes have attracted increasing attention in recent years but still face problems in terms of stability under oxidative conditions. The structure of the iron(II) complex [1,1'-bis(pyridin-2-yl)-2,2-bi(1H-imidazole)-κN(3)][3,3'-bis(pyridin-2-yl-κN)-1,1'-methanediylbi(1H-imidazol-2-yl-κC(2))](trimethylphosphane-κP)iron(II) bis(hexafluoridophosphate), [Fe(C17H14N6)(C16H12N6)(C3H9P)](PF6)2, features coordination by an organic decomposition product of a tetradentate NHC ligand in an axial position. The decomposition product, a C-C-coupled biimidazole, is trapped by coordination to still-intact iron(II) complexes. Insights into the structural features of the organic decomposition products might help to improve the stability of oxidation catalysts under harsh conditions.

  4. Data structures II essentials

    CERN Document Server

    Smolarski, Dennis C

    2012-01-01

    REA's Essentials provide quick and easy access to critical information in a variety of different fields, ranging from the most basic to the most advanced. As its name implies, these concise, comprehensive study guides summarize the essentials of the field covered. Essentials are helpful when preparing for exams, doing homework and will remain a lasting reference source for students, teachers, and professionals. Data Structures II includes sets, trees, advanced sorting, elementary graph theory, hashing, memory management and garbage collection, and appendices on recursion vs. iteration, alge

  5. The structure of a cholesterol-trapping protein

    Science.gov (United States)

    cholesterol-trapping protein Contact: Dan Krotz, dakrotz@lbl.gov Berkeley Lab Science Beat Lab website index Institute researchers determined the three-dimensional structure of a protein that controls cholesterol level in the bloodstream. Knowing the structure of the protein, a cellular receptor that ensnares

  6. Fundamental limit of light trapping in grating structures

    KAUST Repository

    Yu, Zongfu

    2010-08-11

    We use a rigorous electromagnetic approach to analyze the fundamental limit of light-trapping enhancement in grating structures. This limit can exceed the bulk limit of 4n 2, but has significant angular dependency. We explicitly show that 2D gratings provide more enhancement than 1D gratings. We also show the effects of the grating profile’s symmetry on the absorption enhancement limit. Numerical simulations are applied to support the theory. Our findings provide general guidance for the design of grating structures for light-trapping solar cells.

  7. Computing the Partition Function for Kinetically Trapped RNA Secondary Structures

    Science.gov (United States)

    Lorenz, William A.; Clote, Peter

    2011-01-01

    An RNA secondary structure is locally optimal if there is no lower energy structure that can be obtained by the addition or removal of a single base pair, where energy is defined according to the widely accepted Turner nearest neighbor model. Locally optimal structures form kinetic traps, since any evolution away from a locally optimal structure must involve energetically unfavorable folding steps. Here, we present a novel, efficient algorithm to compute the partition function over all locally optimal secondary structures of a given RNA sequence. Our software, RNAlocopt runs in time and space. Additionally, RNAlocopt samples a user-specified number of structures from the Boltzmann subensemble of all locally optimal structures. We apply RNAlocopt to show that (1) the number of locally optimal structures is far fewer than the total number of structures – indeed, the number of locally optimal structures approximately equal to the square root of the number of all structures, (2) the structural diversity of this subensemble may be either similar to or quite different from the structural diversity of the entire Boltzmann ensemble, a situation that depends on the type of input RNA, (3) the (modified) maximum expected accuracy structure, computed by taking into account base pairing frequencies of locally optimal structures, is a more accurate prediction of the native structure than other current thermodynamics-based methods. The software RNAlocopt constitutes a technical breakthrough in our study of the folding landscape for RNA secondary structures. For the first time, locally optimal structures (kinetic traps in the Turner energy model) can be rapidly generated for long RNA sequences, previously impossible with methods that involved exhaustive enumeration. Use of locally optimal structure leads to state-of-the-art secondary structure prediction, as benchmarked against methods involving the computation of minimum free energy and of maximum expected accuracy. Web server

  8. Computing the partition function for kinetically trapped RNA secondary structures.

    Directory of Open Access Journals (Sweden)

    William A Lorenz

    Full Text Available An RNA secondary structure is locally optimal if there is no lower energy structure that can be obtained by the addition or removal of a single base pair, where energy is defined according to the widely accepted Turner nearest neighbor model. Locally optimal structures form kinetic traps, since any evolution away from a locally optimal structure must involve energetically unfavorable folding steps. Here, we present a novel, efficient algorithm to compute the partition function over all locally optimal secondary structures of a given RNA sequence. Our software, RNAlocopt runs in O(n3 time and O(n2 space. Additionally, RNAlocopt samples a user-specified number of structures from the Boltzmann subensemble of all locally optimal structures. We apply RNAlocopt to show that (1 the number of locally optimal structures is far fewer than the total number of structures--indeed, the number of locally optimal structures approximately equal to the square root of the number of all structures, (2 the structural diversity of this subensemble may be either similar to or quite different from the structural diversity of the entire Boltzmann ensemble, a situation that depends on the type of input RNA, (3 the (modified maximum expected accuracy structure, computed by taking into account base pairing frequencies of locally optimal structures, is a more accurate prediction of the native structure than other current thermodynamics-based methods. The software RNAlocopt constitutes a technical breakthrough in our study of the folding landscape for RNA secondary structures. For the first time, locally optimal structures (kinetic traps in the Turner energy model can be rapidly generated for long RNA sequences, previously impossible with methods that involved exhaustive enumeration. Use of locally optimal structure leads to state-of-the-art secondary structure prediction, as benchmarked against methods involving the computation of minimum free energy and of maximum expected

  9. Dependence of the trapping regions with the radial electric field in TJ-II

    International Nuclear Information System (INIS)

    Guasp, J.; Liniers, M.

    1997-01-01

    The influence of the electric field upon the radial and angular distributions of trapped ions of energies between 0.1 and 1 keV in TJ-II is analysed. Near the magnetic axis, with moderate electric fields, the trapped fraction increases for negative potentials and decreases for positive ones. Nevertheless for high potentials this decreasing for positive sign can be reversed. Near the plasma periphery trapping is affected only for high potentials and always increases, independently of the potential sign. The sensibility to negative potentials is always higher than for the positive ones. These trapping changes are almost uniform in poloidal and toroidal angular profiles and affect mainly to marginally trapped or passing particles. Nevertheless for high potentials or energie the resonances modify this behaviour and inhibit the increasing of trapping in the outer side or the torus. For the locally trapped population fraction a steady decrease with the potential appears independently of the sign, except very near the magnetic axis or the plasma periphery. The global result of all these partial effects is the presence of a wide trapping minimum for moderate positive electric potential, potential that increases with the ion energy as well as a strong increase for high electric fields of either sign, more visible for negative potentials and high energies. For the locally trapped population a steady decrease with potential appears independently of the sign. All these effects can be explained by the combined action of the appearance and elimination of radial magnetic barriers and of the electric field resonances. (Author)

  10. Forces of vortice trapping and critical current in type II superconductors

    International Nuclear Information System (INIS)

    Bormio, C.

    1985-12-01

    The vortice-centers interactions of trapping in type II superconductor materials were studied by two theories: thermodynamic (Hampshire-Taylor) and microscopic (Larkin - Ovchinnikov). The study was applied to NbTi with composition of 50% weight of Ti. They are commercial cables containing 361 filaments with final diameter of 0.35 mm for the wire and 9.2 μm foi filaments. The material presents high deformation rate in area and high density of dislocations. These defects actuate as centers of trapping. Variations in themomechanical treatments of superconductor cables modify the interaction mechanisms. The specific mechanism for each treatment type was identified. Measurements of critical current density in function of magnetic field in the range from 1 to 7 Tesla were done, which the usual superconductor parameters as upper critical field and Ginzburg - Landau (Kappa-k) parameter are estimated from literature data. (M.C.K.) [pt

  11. Disorder Improves Light Absorption in Thin Film Silicon Solar Cells with Hybrid Light Trapping Structure

    Directory of Open Access Journals (Sweden)

    Yanpeng Shi

    2016-01-01

    Full Text Available We present a systematic simulation study on the impact of disorder in thin film silicon solar cells with hybrid light trapping structure. For the periodical structures introducing certain randomness in some parameters, the nanophotonic light trapping effect is demonstrated to be superior to their periodic counterparts. The nanophotonic light trapping effect can be associated with the increased modes induced by the structural disorders. Our study is a systematic proof that certain disorder is conceptually an advantage for nanophotonic light trapping concepts in thin film solar cells. The result is relevant to the large field of research on nanophotonic light trapping which currently investigates and prototypes a number of new concepts including disordered periodic and quasiperiodic textures. The random effect on the shape of the pattern (position, height, and radius investigated in this paper could be a good approach to estimate the influence of experimental inaccuracies for periodic or quasi-periodic structures.

  12. First results on dense plasma confinement at the multimirror open trap GOL-3-II

    International Nuclear Information System (INIS)

    Koidan, V.S.; Arzhannikov, A.V.; Astrelin, V.T.

    2001-01-01

    First results of experiments on plasma confinement in multimirror open trap GOL-3-II are presented. This facility is an open trap with total length of 17 m intended for confinement of a relatively dense (10 15 -10 17 cm -3 ) plasma in axially-symmetrical magnetic system. The plasma heating is provided by a high-power electron beam (1 MeV, 30 kA, 8 ms, 200 kJ). New phase of the experiments is aimed to confinement of high-β thermalized plasma. Two essential modifications of the facility have been done. First, plasma column was separated by vacuum sections from the beam accelerator and exit beam receiver. Second, the magnetic field on part of the solenoid was reconfigured into multimirror system with H max /H min ∼1.5 and 22 cm cell length. Results of the experiments at modified configuration of the device indicate that the confinement time of the plasma with n e ∼(0, 5/5)·10 15 cm -3 and T e ∼1 keV increases more than order of magnitude. (author)

  13. Dependence of direct losses and trapping properties with the magnetic configuration in TJ-II

    International Nuclear Information System (INIS)

    Guasp, J.; Liniers, M.

    1998-05-01

    The former studies concerning direct losses, disymmetries, trapping and radial electric field effects for intermediate energy ions have been extended to several magnetic configurations in TJ-II. In the absence of electric field there are strong similarities in the behaviour of all configurations: disymmetries, loss distributions at plasma border, radial and angular profiles, etc. Generally the differences are only quantitative and dominated by the magnetic ripple at border, that is clearly related with the configuration radius. This qualitative similarity disappears in the presence of a radial electric field. The field resonance are at the origin of these differences. A simple model reproduces correctly the ordering and degree of influence of these resonances. Except when the 0 resonance predominates the los distributions at plasma border move always in the direction of the induced poloidal rotation. The los radial profiles are strongly affected by the -2 Resonance, that can provoke the appearance of lost passing ions well inside the plasma. Instead the radial and angular profiles for trapping are only slightly affected by the -2 Resonance, while the 0 Resonance has a very strong influence there

  14. Crystal Structure of Rat Carnitine Palmitoyltransferase II (CPT-II)

    Energy Technology Data Exchange (ETDEWEB)

    Hsiao,Y.; Jogl, G.; Esser, V.; Tong, L.

    2006-01-01

    Carnitine palmitoyltransferase II (CPT-II) has a crucial role in the {beta}-oxidation of long-chain fatty acids in mitochondria. We report here the crystal structure of rat CPT-II at 1.9 Angstroms resolution. The overall structure shares strong similarity to those of short- and medium-chain carnitine acyltransferases, although detailed structural differences in the active site region have a significant impact on the substrate selectivity of CPT-II. Three aliphatic chains, possibly from a detergent that is used for the crystallization, were found in the structure. Two of them are located in the carnitine and CoA binding sites, respectively. The third aliphatic chain may mimic the long-chain acyl group in the substrate of CPT-II. The binding site for this aliphatic chain does not exist in the short- and medium-chain carnitine acyltransferases, due to conformational differences among the enzymes. A unique insert in CPT-II is positioned on the surface of the enzyme, with a highly hydrophobic surface. It is likely that this surface patch mediates the association of CPT-II with the inner membrane of the mitochondria.

  15. Advanced ion trap structures with integrated tools for qubit manipulation

    Science.gov (United States)

    Sterk, J. D.; Benito, F.; Clark, C. R.; Haltli, R.; Highstrete, C.; Nordquist, C. D.; Scott, S.; Stevens, J. E.; Tabakov, B. P.; Tigges, C. P.; Moehring, D. L.; Stick, D.; Blain, M. G.

    2012-06-01

    We survey the ion trap fabrication technologies available at Sandia National Laboratories. These include four metal layers, precision backside etching, and low profile wirebonds. We demonstrate loading of ions in a variety of ion traps that utilize these technologies. Additionally, we present progress towards integration of on-board filtering with trench capacitors, photon collection via an optical cavity, and integrated microwave electrodes for localized hyperfine qubit control and magnetic field gradient quantum gates. [4pt] This work was supported by Sandia's Laboratory Directed Research and Development (LDRD) Program and the Intelligence Advanced Research Projects Activity (IARPA). Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the US Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  16. Coherent structural trapping through wave packet dispersion during photoinduced spin state switching

    DEFF Research Database (Denmark)

    Lemke, Henrik T.; Kjær, Kasper Skov; Hartsock, Robert

    2017-01-01

    The description of ultrafast nonadiabatic chemical dynamics during molecular photo-transformations remains challenging because electronic and nuclear configurations impact each other and cannot be treated independently. Here we gain experimental insights, beyond the Born-Oppenheimer approximation...... is distinguished from the structural trapping dynamics, which launches a coherent oscillating wave packet (265 fs period), clearly identified as molecular breathing. Throughout the structural trapping, the dispersion of the wave packet along the reaction coordinate reveals details of intramolecular vibronic...

  17. Structures and mechanisms in clay nanopore trapping of structurally-different fluoroquinolone antimicrobials.

    Science.gov (United States)

    Okaikue-Woodi, Fanny E K; Kelch, Sabrina E; Schmidt, Michael P; Enid Martinez, Carmen; Youngman, Randall E; Aristilde, Ludmilla

    2018-03-01

    Smectite clay nanoparticles are implicated in the retention of antimicrobials within soils and sediments; these clays are also inspected as drug carriers in physiological systems. Cation exchange is considered the primary adsorption mechanism of antimicrobials within smectite nanopores. However, a dual role of acid-base chemistry and adsorptive structures is speculated by recent studies. Using the prototypical smectite clay montmorillonite, we employed a combination of X-ray diffraction (XRD), nuclear magnetic resonance, attenuated total reflectance-Fourier transform infrared spectroscopy, and molecular dynamics simulations to investigate the interlayer nanopore trapping of two structurally-different fluoroquinolone (FQ) antimicrobials with similar acid-base chemistry: ciprofloxacin (a first-generation FQ) and moxifloxacin (a third-generation FQ). Greater sorption at pH 5.0 than at pH 7.0 for both FQs was consistent with cation-exchange of positively-charged species. However, the clay exhibited a near twofold higher sorption capacity for moxifloxacin than for ciprofloxacin. This difference was shown by the XRD data to be accompanied by enhanced trapping of moxifloxacin within the clay interlayers. Using the XRD-determined nanopore sizes, we performed molecular dynamics simulations of thermodynamically-favorable model adsorbates, which revealed that ciprofloxacin was adsorbed parallel to the clay surface but moxifloxacin adopted a tilted conformation across the nanopore. These conformations resulted in more slowly-exchanged than quickly-exchanged Na complexes with ciprofloxacin compared with moxifloxacin. These different Na populations were also captured by 23 Na nuclear magnetic resonance. Furthermore, the simulated adsorbates uncovered different complexation interactions that were corroborated by infrared spectroscopy. Therefore, beyond acid-base chemistry, our findings imply that distinct adsorbate structures control antimicrobial trapping within clay nanopores

  18. Foam flow in a model porous medium: II. The effect of trapped gas.

    Science.gov (United States)

    Jones, S A; Getrouw, N; Vincent-Bonnieu, S

    2018-05-09

    Gas trapping is an important mechanism in both Water or Surfactant Alternating Gas (WAG/SAG) and foam injection processes in porous media. Foams for enhanced oil recovery (EOR) can increase sweep efficiency as they decrease the gas relative permeability, and this is mainly due to gas trapping. However, gas trapping mechanisms are poorly understood. Some studies have been performed during corefloods, but little work has been carried out to describe the bubble trapping behaviour at the pore scale. We have carried out foam flow tests in a micromodel etched with an irregular hexagonal pattern. Image analysis of the foam flow allowed the bubble centres to be tracked and local velocities to be obtained. It was found that the flow in the micromodel is dominated by intermittency and localized zones of trapped gas. The quantity of trapped gas was measured both by considering the fraction of bubbles that were trapped (via velocity thresholding) and by measuring the area fraction containing immobile gas (via image analysis). A decrease in the quantity of trapped gas was observed for both increasing total velocity and increasing foam quality. Calculations of the gas relative permeability were made with the Brooks Corey equation, using the measured trapped gas saturations. The results showed a decrease in gas relative permeabilities, and gas mobility, for increasing fractions of trapped gas. It is suggested that the shear thinning behaviour of foam could be coupled to the saturation of trapped gas.

  19. Characterization of Ni(II) complexes of Schiff bases of amino acids and (S)-N-(2-benzoylphenyl)-1-benzylpyrrolidine-2-carboxamide using ion trap and QqTOF electrospray ionization tandem mass spectrometry

    NARCIS (Netherlands)

    Jirasko, Robert; Holcapek, Michal; Kolarova, Lenka; Nadvornik, Milan; Popkov, Alexander

    This work demonstrates the application of electrospray ionization mass spectrometry (ESI-MS) using two different mass analyzers, ion trap and hybrid quadrupole time-of-flight (QqTOF) mass analyzer, for the structural characterization of Ni(II) complexes of Schiff bases of

  20. MOS Capacitance—Voltage Characteristics II. Sensitivity of Electronic Trapping at Dopant Impurity from Parameter Variations

    International Nuclear Information System (INIS)

    Jie Binbin; Sah Chihtang

    2011-01-01

    Low-frequency and high-frequency Capacitance—Voltage (C—V) curves of Metal—Oxide—Semiconductor Capacitors (MOSC), including electron and hole trapping at the dopant donor and acceptor impurities, are presented to illustrate giant trapping capacitances, from > 0.01C OX to > 10C OX . Five device and materials parameters are varied for fundamental trapping parameter characterization, and electrical and optical signal processing applications. Parameters include spatially constant concentration of the dopant-donor-impurity electron trap, N DD , the ground state electron trapping energy level depth measured from the conduction band edge, E C –E D , the degeneracy of the trapped electron at the ground state, g D , the device temperature, T, and the gate oxide thickness, x OX . (invited papers)

  1. Nano-optical conveyor belt, part II: Demonstration of handoff between near-field optical traps.

    Science.gov (United States)

    Zheng, Yuxin; Ryan, Jason; Hansen, Paul; Cheng, Yao-Te; Lu, Tsung-Ju; Hesselink, Lambertus

    2014-06-11

    Optical tweezers have been widely used to manipulate biological and colloidal material, but the diffraction limit of far-field optics makes focused beams unsuitable for manipulating nanoscale objects with dimensions much smaller than the wavelength of light. While plasmonic structures have recently been successful in trapping nanoscale objects with high positioning accuracy, using such structures for manipulation over longer range has remained a significant challenge. In this work, we introduce a conveyor belt design based on a novel plasmonic structure, the resonant C-shaped engraving (CSE). We show how long-range manipulation is made possible by means of handoff between neighboring CSEs, and we present a simple technique for controlling handoff by rotating the polarization of laser illumination. We experimentally demonstrate handoff between a pair of CSEs for polystyrene spheres 200, 390, and 500 nm in diameter. We then extend this technique and demonstrate controlled particle transport down a 4.5 μm long "nano-optical conveyor belt."

  2. Ion Trapping, Storage, and Ejection in Structures for Lossless Ion Manipulations.

    Science.gov (United States)

    Zhang, Xinyu; Garimella, Sandilya V B; Prost, Spencer A; Webb, Ian K; Chen, Tsung-Chi; Tang, Keqi; Tolmachev, Aleksey V; Norheim, Randolph V; Baker, Erin S; Anderson, Gordon A; Ibrahim, Yehia M; Smith, Richard D

    2015-06-16

    A new Structures for Lossless Ion Manipulations (SLIM) module, having electrode arrays patterned on a pair of parallel printed circuit boards (PCB), was constructed and utilized to investigate capabilities for ion trapping at a pressure of 4 Torr. Positive ions were confined by application of RF voltages to a series of inner rung electrodes with alternating phase on adjacent electrodes, in conjunction with positive DC potentials on surrounding guard electrodes on each PCB. An axial DC field was also introduced by stepwise varying the DC potentials applied to the inner rung electrodes to control the ion transport and accumulation inside the ion trapping region. We show that ions can be trapped and accumulated with up to 100% efficiency, stored for at least 5 h with no significant losses, and then could be rapidly ejected from the SLIM trap. The present results provide a foundation for the development of much more complex SLIM devices that facilitate extended ion manipulations.

  3. Formation of oxide-trapped charges in 6H-SiC MOS structures

    Energy Technology Data Exchange (ETDEWEB)

    Yoshikawa, Masahito; Ohshima, Takeshi; Itoh, Hisayoshi; Nashiyama, Isamu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment; Okumura, Hajime; Yoshida, Sadafumi

    1997-03-01

    The silicon and the carbon faces of hexagonal silicon carbide (6H-SiC) substrates were oxidized pyrogenically at 1100degC, and the metal-oxide-semiconductor structures were formed on these faces. The MOS capacitors developed using the silicon and the carbon faces were irradiated with {sup 60}Co gamma-rays under argon atmosphere at room temperature. The bias voltages with the different polarity were applied to the gate electrode during irradiation to examine the formation mechanisms of the trapped charges in the oxides of these MOS capacitors. The amount of the trapped charges in the oxide were obtained from capacitance pulse voltage characteristics. The generation of the trapped charges are affects with not only the absorbed dose but also the bias polarity applied to the gate electrodes during irradiation. The formation mechanisms of the trapped charges in the oxides were estimated in conjunction with the surface orientation of 6H-SiC substrates. (author)

  4. Structure and dynamics of ion clusters in linear octupole traps: Phase diagrams, chirality, and melting mechanisms

    International Nuclear Information System (INIS)

    Yurtsever, E.; Onal, E. D.; Calvo, F.

    2011-01-01

    The stable structures and melting dynamics of clusters of identical ions bound by linear octupole radiofrequency traps are theoretically investigated by global optimization methods and molecular dynamics simulations. By varying the cluster sizes in the range of 10-1000 ions and the extent of trap anisotropy by more than one order of magnitude, we find a broad variety of stable structures based on multiple rings at small sizes evolving into tubular geometries at large sizes. The binding energy of these clusters is well represented by two contributions arising from isotropic linear and octupolar traps. The structures generally exhibit strong size effects, and chiral arrangements spontaneously emerge in many crystals. Sufficiently large clusters form nested, coaxial tubes with different thermal stabilities. As in isotropic octupolar clusters, the inner tubes melt at temperatures that are lower than the overall melting point.

  5. Effects of the radial electrical field on the drifts, trapping and particle orbits in TJ-II

    International Nuclear Information System (INIS)

    Guasp, J.; Liniers, M.

    1997-01-01

    In this study a detailed analysis of the effect of radial electric fields on drifts, trapping and trajectories for ions of low and intermediate energy (0.1-1 keV) in the helical axis stellarator TJ-II has been performed. In TJ-II the drift velocities have the same rotation direction than the Hard Core (HC, the same than the plasma) with predominance of the vertical downwards component. The intensity is higher near the HC and in the outwards direction. These trends create strong asymmetries in losses even in the absence of electric field. When an electric field is present the poloidal components of the drift velocity predominates modifying deeply the orbit behaviour. Positive electric fields produce internal radial trapping barriers and have a tendency to eliminate the external ones. The opposite happens for negative fields. These facts alterate deeply the tapping and confinement properties of the particles. All these analysis will be used as a basis for the understanding of the modifications on the loss distribution, trapping regions and loss cones for TJ-II that will be addressed in forthcoming studies. (Author)

  6. Freely floating structures trapping time-harmonic water waves (revisited)

    OpenAIRE

    Kuznetsov, Nikolay; Motygin, Oleg

    2014-01-01

    We study the coupled small-amplitude motion of the mechanical system consisting of infinitely deep water and a structure immersed in it. The former is bounded above by a free surface, whereas the latter is formed by an arbitrary finite number of surface-piercing bodies floating freely. The mathematical model of time-harmonic motion is a spectral problem in which the frequency of oscillations serves as the spectral parameter. It is proved that there exist axisymmetric structures consisting of ...

  7. Structural, Bioinformatic, and In Vivo Analyses of Two Treponema pallidum Lipoproteins Reveal a Unique TRAP Transporter

    Energy Technology Data Exchange (ETDEWEB)

    Deka, Ranjit K.; Brautigam, Chad A.; Goldberg, Martin; Schuck, Peter; Tomchick, Diana R.; Norgard, Michael V. (NIH); (UTSMC)

    2012-05-25

    Treponema pallidum, the bacterial agent of syphilis, is predicted to encode one tripartite ATP-independent periplasmic transporter (TRAP-T). TRAP-Ts typically employ a periplasmic substrate-binding protein (SBP) to deliver the cognate ligand to the transmembrane symporter. Herein, we demonstrate that the genes encoding the putative TRAP-T components from T. pallidum, tp0957 (the SBP), and tp0958 (the symporter), are in an operon with an uncharacterized third gene, tp0956. We determined the crystal structure of recombinant Tp0956; the protein is trimeric and perforated by a pore. Part of Tp0956 forms an assembly similar to those of 'tetratricopeptide repeat' (TPR) motifs. The crystal structure of recombinant Tp0957 was also determined; like the SBPs of other TRAP-Ts, there are two lobes separated by a cleft. In these other SBPs, the cleft binds a negatively charged ligand. However, the cleft of Tp0957 has a strikingly hydrophobic chemical composition, indicating that its ligand may be substantially different and likely hydrophobic. Analytical ultracentrifugation of the recombinant versions of Tp0956 and Tp0957 established that these proteins associate avidly. This unprecedented interaction was confirmed for the native molecules using in vivo cross-linking experiments. Finally, bioinformatic analyses suggested that this transporter exemplifies a new subfamily of TPATs (TPR-protein-associated TRAP-Ts) that require the action of a TPR-containing accessory protein for the periplasmic transport of a potentially hydrophobic ligand(s).

  8. Charge trapping at organic/self-assembly molecule interfaces studied by electrical switching behaviour in a crosspoint structure

    International Nuclear Information System (INIS)

    Li Yun; Pan Lijia; Pu Lin; Shi Yi; Liu Chuan; Tsukagoshi, Kazuhito

    2012-01-01

    Charge trapping at organic/self-assembly molecule (SAM) interfaces is studied by the electrical switching behaviour in a crosspoint structure, where interfacial charge trapping tunes the potential barrier of the SAM layer. The sample with rubrene exhibits the write-once read-many-times memory effect, which is due to the interfacial charges trapped at deep states. On the other hand, the sample with 2-amino-4,5-dicyanoimidazole presents recyclable conduction transition, which results from the trapped charges distributed at shallow states. Moreover, the percentage of the charges trapped at shallow states can be estimated from electrical transition levels. (paper)

  9. Charge trapping at organic/self-assembly molecule interfaces studied by electrical switching behaviour in a crosspoint structure

    Science.gov (United States)

    Li, Yun; Liu, Chuan; Pan, Lijia; Pu, Lin; Tsukagoshi, Kazuhito; Shi, Yi

    2012-01-01

    Charge trapping at organic/self-assembly molecule (SAM) interfaces is studied by the electrical switching behaviour in a crosspoint structure, where interfacial charge trapping tunes the potential barrier of the SAM layer. The sample with rubrene exhibits the write-once read-many-times memory effect, which is due to the interfacial charges trapped at deep states. On the other hand, the sample with 2-amino-4,5-dicyanoimidazole presents recyclable conduction transition, which results from the trapped charges distributed at shallow states. Moreover, the percentage of the charges trapped at shallow states can be estimated from electrical transition levels.

  10. A Portable Source of Lattice-Trapped and Ultracold Strontium (PLUS), Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to demonstrate the portable source of lattice-trapped, ultracold strontium (PLUS) designed during Phase I. The device uses simplified and robust...

  11. Energy spectrum structure and ''trap'' effects in a three-particle system

    International Nuclear Information System (INIS)

    Simenog, I.V.; Sitnichenko, A.I.

    1982-01-01

    Investigation is made of the threshold energy spectrum structure in a system of three spinless particles depending on the form of two-particle interaction. The correlation dependence of the spectrum and low-energy scattering parameters are shown. A new phenomenon of ''traps'' for the spectrum in a three-particle system with interaction involving components of considerably different ranges is established

  12. MRI diagnosis of trapped periosteum following incomplete closed reduction of distal tibial Salter-Harris II fracture

    International Nuclear Information System (INIS)

    Raman, Subha; Wallace, E.C.

    2011-01-01

    Irreducible fracture of the distal tibial physis due to interposed soft tissue including periosteum is well documented in the orthopedic literature but is uncommon. This condition has been associated with subsequent growth disturbance and requires open reduction. There are very few prior reports of MRI depiction of soft tissue interposition and none of periosteal interposition in the distal tibial physis. This is a relatively common location of physeal injury and related growth disturbance. We present a case of periosteum trapped in the distal tibial physis, diagnosed on MRI, in a Salter-Harris II fracture and its management implications. (orig.)

  13. Effects of the radial electric field on confinement and trapping for non collisional electrons in TJ-II

    International Nuclear Information System (INIS)

    Guasp, J.; Liniers, M.

    1998-01-01

    The effects of radial electric fields on the non collisional losses, asymmetries at plasma border and on the Vacuum Vessel and trapping fractions for 0.1 1 KeV electrons in TJ-II are analysed. This study complements a series, already published, for ions, therefore only the main differences are stressed. Many of these effect are similar for electrons and ions, mainly the drastic decrease of losses with the electric field, the increasing peripherical loss concentration, the strong accumulation on the Hard Core (HC), the modification in the direction of the induced poloidal rotation, similar angular distributions for trapped particles, etc. Nevertheless, there appear also important differences, that in many cases are originated by the higher electron mobility, in particular a higher sensitivity to the electric field, as well to the intensity as to the sign, producing a faster drop in electron losses for positive potential and a higher asymmetry in the sign dependence. Most of these electron losses exit through the upper side of the plasma, the opposite happens for ions. The strong concentration on the HC appears, many, on the PL-1 plate (the one that is placed upside for toroidal angle φ=0 degree centigree), instead of the opposite PL-2 plate for ions.Finally, for the analysed energy range, there is no variation of electron trapping with the potential nor resonant effect. (Author) 8 refs

  14. Slow electron acoustic double layer (SEADL) structures in bi-ion plasma with trapped electrons

    Science.gov (United States)

    Shan, Shaukat Ali; Imtiaz, Nadia

    2018-05-01

    The properties of ion acoustic double layer (IADL) structures in bi-ion plasma with electron trapping are investigated by using the quasi-potential analysis. The κ-distributed trapped electrons number density expression is truncated to some finite order of the electrostatic potential. By utilizing the reductive perturbation method, a modified Schamel equation which describes the evolution of the slow electron acoustic double layer (SEADL) with the modified speed due to the presence of bi-ion species is investigated. The Sagdeev-like potential has been derived which accounts for the effect of the electron trapping and superthermality in a bi-ion plasma. It is found that the superthermality index, the trapping efficiency of electrons, and ion to electron temperature ratio are the inhibiting parameters for the amplitude of the slow electron acoustic double layers (SEADLs). However, the enhanced population of the cold ions is found to play a supportive role for the low frequency DLs in bi-ion plasmas. The illustrations have been presented with the help of the bi-ion plasma parameters in the Earth's ionosphere F-region.

  15. Structural Source of the Trap of ICT Advancement - Lessons from World ICT Top Leaders

    OpenAIRE

    Watanabe, Chihiro; Naveed, Kashif; Zhao, Weilin

    2014-01-01

    In light of the significant consequence of the trap of dramatic advancement of information and communication technology (ICT) in the global economy, both nations and firms that have been compelling their productivity decline. This resulted in great stagnation of ICT advanced economies and therefore its structural sources were analyzed. Based on an empirical analysis tracing, the trend in marginal productivity of ICT and its subsequent prices among the top ICT leaders in the ...

  16. Observation of a structural transition for coulomb crystals in a linear Paul trap

    DEFF Research Database (Denmark)

    Kjærgaard, N.; Drewsen, M.

    2003-01-01

    A structural transition for laser cooled ion Coulomb crystals in a linear Paul trap just above the stability limit of parametrically resonant excitation of bulk plasma modes has been observed. In contrast to the usual spheroidal shell structures present below the stability limit, the ions arrange...... in a "string-of-disks" configuration. The spheroidal envelopes of the string-of-disks structures are in agreement with results from cold fluid theory usually valid for ion Coulomb crystals if the ion systems are assumed to be rotating collectively....

  17. Observation of a structural transition for Coulomb crystals in a linear Paul trap

    International Nuclear Information System (INIS)

    Kjaergaard, Niels; Drewsen, Michael

    2003-01-01

    A structural transition for laser cooled ion Coulomb crystals in a linear Paul trap just above the stability limit of parametrically resonant excitation of bulk plasma modes has been observed. In contrast to the usual spheroidal shell structures present below the stability limit, the ions arrange in a 'string-of-disks' configuration. The spheroidal envelopes of the string-of-disks structures are in agreement with results from cold fluid theory usually valid for ion Coulomb crystals if the ion systems are assumed to be rotating collectively

  18. Comparison between periodic and stochastic parabolic light trapping structures for thin-film microcrystalline Silicon solar cells.

    Science.gov (United States)

    Peters, M; Battaglia, C; Forberich, K; Bläsi, B; Sahraei, N; Aberle, A G

    2012-12-31

    Light trapping is of very high importance for silicon photovoltaics (PV) and especially for thin-film silicon solar cells. In this paper we investigate and compare theoretically the light trapping properties of periodic and stochastic structures having similar geometrical features. The theoretical investigations are based on the actual surface geometry of a scattering structure, characterized by an atomic force microscope. This structure is used for light trapping in thin-film microcrystalline silicon solar cells. Very good agreement is found in a first comparison between simulation and experimental results. The geometrical parameters of the stochastic structure are varied and it is found that the light trapping mainly depends on the aspect ratio (length/height). Furthermore, the maximum possible light trapping with this kind of stochastic structure geometry is investigated. In a second step, the stochastic structure is analysed and typical geometrical features are extracted, which are then arranged in a periodic structure. Investigating the light trapping properties of the periodic structure, we find that it performs very similar to the stochastic structure, in agreement with reports in literature. From the obtained results we conclude that a potential advantage of periodic structures for PV applications will very likely not be found in the absorption enhancement in the solar cell material. However, uniformity and higher definition in production of these structures can lead to potential improvements concerning electrical characteristics and parasitic absorption, e.g. in a back reflector.

  19. A Collapsin Response Mediator Protein 2 Isoform Controls Myosin II-Mediated Cell Migration and Matrix Assembly by Trapping ROCK II

    Science.gov (United States)

    Morgan-Fisher, Marie; Wait, Robin; Couchman, John R.; Wewer, Ulla M.

    2012-01-01

    Collapsin response mediator protein 2 (CRMP-2) is known as a regulator of neuronal polarity and differentiation through microtubule assembly and trafficking. Here, we show that CRMP-2 is ubiquitously expressed and a splice variant (CRMP-2L), which is expressed mainly in epithelial cells among nonneuronal cells, regulates myosin II-mediated cellular functions, including cell migration. While the CRMP-2 short form (CRMP-2S) is recognized as a substrate of the Rho-GTP downstream kinase ROCK in neuronal cells, a CRMP-2 complex containing 2L not only bound the catalytic domain of ROCK II through two binding domains but also trapped and inhibited the kinase. CRMP-2L protein levels profoundly affected haptotactic migration and the actin-myosin cytoskeleton of carcinoma cells as well as nontransformed epithelial cell migration in a ROCK activity-dependent manner. Moreover, the ectopic expression of CRMP-2L but not -2S inhibited fibronectin matrix assembly in fibroblasts. Underlying these responses, CRMP-2L regulated the kinase activity of ROCK II but not ROCK I, independent of GTP-RhoA levels. This study provides a new insight into CRMP-2 as a controller of myosin II-mediated cellular functions through the inhibition of ROCK II in nonneuronal cells. PMID:22431514

  20. Depth profiling of oxide-trapped charges in 6H-SiC MOS structures by slant etching method

    Energy Technology Data Exchange (ETDEWEB)

    Saitoh, Kazunari; Takahashi, Yoshihiro; Ohnishi, Kazunori [Nihon Univ., Tokyo (Japan). Coll. of Science and Technology; Yoshikawa, Masahito; Ohshima, Takeshi; Itoh, Hisayoshi; Nashiyama, Isamu

    1997-03-01

    In this paper, we propose a method to evaluate the depth profile of trapped charges in an oxide layer on SiC. Using this method, 6H-SiC MOS structures with different oxide thickness were fabricated on the same substrate under the same oxidation condition, and the depth profile of oxide-trapped charges before and after {sup 60}Co-gamma ray irradiation were obtained. It is found, from the depth profiling, that the trapping mechanism of electrons and holes in the oxide strongly depends on the bias polarity during irradiation, and these charges are trapped near 6H-SiC/SiO{sub 2} interface. We believe that this method is very useful for estimation of the oxide-trapped charges in 6H-SiC MOS structures. (author)

  1. Fabrication of the replica templated from butterfly wing scales with complex light trapping structures

    Science.gov (United States)

    Han, Zhiwu; Li, Bo; Mu, Zhengzhi; Yang, Meng; Niu, Shichao; Zhang, Junqiu; Ren, Luquan

    2015-11-01

    The polydimethylsiloxane (PDMS) positive replica templated twice from the excellent light trapping surface of butterfly Trogonoptera brookiana wing scales was fabricated by a simple and promising route. The exact SiO2 negative replica was fabricated by using a synthesis method combining a sol-gel process and subsequent selective etching. Afterwards, a vacuum-aided process was introduced to make PDMS gel fill into the SiO2 negative replica, and the PDMS gel was solidified in an oven. Then, the SiO2 negative replica was used as secondary template and the structures in its surface was transcribed onto the surface of PDMS. At last, the PDMS positive replica was obtained. After comparing the PDMS positive replica and the original bio-template in terms of morphology, dimensions and reflectance spectra and so on, it is evident that the excellent light trapping structures of butterfly wing scales were inherited by the PDMS positive replica faithfully. This bio-inspired route could facilitate the preparation of complex light trapping nanostructure surfaces without any assistance from other power-wasting and expensive nanofabrication technologies.

  2. Multiple trapping on a comb structure as a model of electron transport in disordered nanostructured semiconductors

    International Nuclear Information System (INIS)

    Sibatov, R. T.; Morozova, E. V.

    2015-01-01

    A model of dispersive transport in disordered nanostructured semiconductors has been proposed taking into account the percolation structure of a sample and joint action of several mechanisms. Topological and energy disorders have been simultaneously taken into account within the multiple trapping model on a comb structure modeling the percolation character of trajectories. The joint action of several mechanisms has been described within random walks with a mixture of waiting time distributions. Integral transport equations with fractional derivatives have been obtained for an arbitrary density of localized states. The kinetics of the transient current has been calculated within the proposed new model in order to analyze time-of-flight experiments for nanostructured semiconductors

  3. The Galeta Oil Spill. II. Unexpected Persistence of Oil Trapped in Mangrove Sediments

    Science.gov (United States)

    Burns, K. A.; Garrity, S. D.; Jorissen, D.; MacPherson, J.; Stoelting, M.; Tierney, J.; Yelle-Simmons, L.

    1994-04-01

    Sediment chemistry studies, undertaken as part of the long-term assessment of the Bahía las Minas (Panamá) oil spill, showed the unexpected persistence of the full range of aromatic hydrocarbon residues of the spilled crude oil in anoxic muds of coastal mangroves. Mangrove muds served as long-term reservoirs for chronic contamination of contiguous coastal communities for over 5 years. One result of the repeated history of oil pollution incidents along this coast was an increased proportion of dead mangrove ( Rhizophora mangle) roots in sediment cores which was related to contaminant loading and was detectable for at least 20 years after major oil spills. We suggest that this is the minimum time-scale that is to be expected for the loss of toxicity of oil trapped in muddy coastal habitats impacted by catastrophic oil spills.

  4. Enhanced quantum sensing with multi-level structures of trapped ions

    DEFF Research Database (Denmark)

    Aharon, N.; Drewsen, Michael; Retzker, A.

    2017-01-01

    , robustness to both external and controller noise is achieved. We consider trapped-ion based implementation via the dipole transitions, which is relevant for several types of ions, such as the $^{40}{\\rm{Ca}}^{+}$, $^{88}{\\rm{Sr}}^{+}$, and the $^{138}{\\rm{Ba}}^{+}$ ions. Taking experimental errors...... of magnitude of the sensitivity. In addition, we present a microwave based sensing scheme that is suitable for ions with a hyperfine structure, such as the $^{9}{\\rm{Be}}^{+}$,$^{25}{\\rm{Mg}}^{+}$,$^{43}{\\rm{Ca}}^{+}$,$^{87}{\\rm{Sr}}^{+}$,$^{137}{\\rm{Ba}}^{+}$,$^{111}{\\rm{Cd}}^{+}$,$^{171}{\\rm...

  5. Two-dimensional spatial structure of the dissipative trapped-electron mode

    International Nuclear Information System (INIS)

    Rewoldt, G.; Tang, W.M.; Frieman, E.A.

    1976-09-01

    This paper deals with the complete two-dimensional structure of the dissipative trapped-electron mode over its full width, which may extend over several mode-rational surfaces. The complete integro-differential equation is studied in the limit k/sub r/rho/sub i/ less than 1, where rho/sub i/ is the ion gyroradius, and k/sub r/, the radial wavenumber, is regarded as a differential operator. This is converted into a matrix equation which is then solved by standard numerical methods

  6. Spectroscopy of Deep Traps in Cu2S-CdS Junction Structures

    Directory of Open Access Journals (Sweden)

    Eugenijus Gaubas

    2012-12-01

    Full Text Available Cu2S-CdS junctions of the polycrystalline material layers have been examined by combining the capacitance deep level transient spectroscopy technique together with white LED light additional illumination (C-DLTS-WL and the photo-ionization spectroscopy (PIS implemented by the photocurrent probing. Three types of junction structures, separated by using the barrier capacitance characteristics of the junctions and correlated with XRD distinguished precipitates of the polycrystalline layers, exhibit different deep trap spectra within CdS substrates.

  7. Semiconductor heterostructures and optimization of light-trapping structures for efficient thin-film solar cells

    International Nuclear Information System (INIS)

    McPheeters, Claiborne O; Yu, Edward T; Hu, Dongzhi; Schaadt, Daniel M

    2012-01-01

    Sub-wavelength photonic structures and nanoscale materials have the potential to greatly improve the efficiencies of solar cells by enabling maximum absorption of sunlight. Semiconductor heterostructures provide versatile opportunities for improving absorption of infrared radiation in photovoltaic devices, which accounts for half of the power in the solar spectrum. These ideas can be combined in quantum-well solar cells and related structures in which sub-wavelength metal and dielectric scattering elements are integrated for light trapping. Measurements and simulations of GaAs solar cells with less than one micron of active material demonstrate the benefits of incorporating In(Ga)As quantum-wells and quantum-dots to improve their performance. Simulations that incorporate a realistic model of absorption in quantum-wells show that the use of broadband photonic structures with such devices can substantially improve the benefit of incorporating heterostructures, enabling meaningful improvements in their performance

  8. Thermally induced structural modifications and O2 trapping in highly porous silica nanoparticles

    International Nuclear Information System (INIS)

    Alessi, A.; Agnello, S.; Iovino, G.; Buscarino, G.; Melodia, E.G.; Cannas, M.; Gelardi, F.M.

    2014-01-01

    In this work we investigate by Raman spectroscopy the effect of isochronal (2 h) thermal treatments in air in the temperature range 200–1000 °C of amorphous silicon dioxide porous nanoparticles with diameters ranging from 5 up to 15 nm and specific surface 590–690 m 2 /g. Our results indicate that the amorphous structure changes similarly to other porous systems previously investigated, in fact superficial SiOH groups are removed, Si–O–Si linkages are created and the ring statistic is modified, furthermore these data evidence that the three membered rings do not contribute significantly to the Raman signal detected at about 495 cm −1 . In addition, after annealing at 900 and 1000 °C we noted the appearance of the O 2 emission at 1272 nm, absent in the not treated samples. The measure of the O 2 emission has been combined with electron paramagnetic resonance measurements of the γ irradiation induced HO · 2 radicals to investigate the O 2 content per mass unit of thin layers of silica. Our data reveal that the porous nanoparticles have a much lower ability to trap O 2 molecules per mass units than nonporous silica supporting a model by which O 2 trapping inside a surface layer of about 1 nm of silica is always limited. - Highlights: • O 2 emission and HO · 2 electron paramagnetic resonance signals are investigated. • Silica surface ability to trap O 2 molecules is explored by thermal treatments. • Raman study of thermally induced structural changes in porous silica nanoparticles. • Raman signal attributable to the three membered rings in silica

  9. Thermally induced structural modifications and O{sub 2} trapping in highly porous silica nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Alessi, A., E-mail: antonino.alessi@unipa.it; Agnello, S.; Iovino, G.; Buscarino, G.; Melodia, E.G.; Cannas, M.; Gelardi, F.M.

    2014-12-15

    In this work we investigate by Raman spectroscopy the effect of isochronal (2 h) thermal treatments in air in the temperature range 200–1000 °C of amorphous silicon dioxide porous nanoparticles with diameters ranging from 5 up to 15 nm and specific surface 590–690 m{sup 2}/g. Our results indicate that the amorphous structure changes similarly to other porous systems previously investigated, in fact superficial SiOH groups are removed, Si–O–Si linkages are created and the ring statistic is modified, furthermore these data evidence that the three membered rings do not contribute significantly to the Raman signal detected at about 495 cm{sup −1}. In addition, after annealing at 900 and 1000 °C we noted the appearance of the O{sub 2} emission at 1272 nm, absent in the not treated samples. The measure of the O{sub 2} emission has been combined with electron paramagnetic resonance measurements of the γ irradiation induced HO{sup ·}{sub 2} radicals to investigate the O{sub 2} content per mass unit of thin layers of silica. Our data reveal that the porous nanoparticles have a much lower ability to trap O{sub 2} molecules per mass units than nonporous silica supporting a model by which O{sub 2} trapping inside a surface layer of about 1 nm of silica is always limited. - Highlights: • O{sub 2} emission and HO{sup ·}{sub 2} electron paramagnetic resonance signals are investigated. • Silica surface ability to trap O{sub 2} molecules is explored by thermal treatments. • Raman study of thermally induced structural changes in porous silica nanoparticles. • Raman signal attributable to the three membered rings in silica.

  10. Wavelength-selective bleaching of the optical spectra of trapped electrons in organic glasses. II

    International Nuclear Information System (INIS)

    Paraszczak, J.; Willard, J.E.

    1979-01-01

    Further resolution of the inhomogeneous optical spectra of trapped electrons (e - /sub t/) in organic glasses has been obtained from wavelength selective bleaching and thermal decay studies on 3-methylpentane-d 14 (3MP-d 14 ) and 2-methyltetrahydrofuran (MTHF) following γ irradiation in the temperature region of 20 K, and limits on the degree of resolution achievable have been indicated. Exposure of 3MP-d 14 to light of wavelengths >2100 nm (from a tunable laser) reduces the optical densities at the bleaching wavelength and longer to zero, while ''peeling off'' a portion of the O.D. at all shorter wavelengths but leaving the remainder of the spectrum unaffected. The fraction of the integrated optical spectrum, ∫OD d (eV), removed by bleaching at each wavelength tested, and also by thermal decay, is equivalent to the fraction of the total e - /sub t/ spins removed and measured by ESR. 1064 nm light bleaches the spectrum nearly uniformly, confirming that the spectra of all of the e - /sub t/ have blue tails with similar ease of bleaching. Heretofore unobserved low temperature thermal decay of e - /sub t/ occurs at 20 and 40 K (20% of the spin concentration in 30 min, 35% in 3h). The rate of decay of the optical spectrum decreases with decreasing wavelength of observation (2.5, 2.2, 1.8, and 1.5 μ), but at each wavelength is the same at 40 K as at 20 K, consistent

  11. Flux expulsion and trapping in rotating discs of type II superconductors

    International Nuclear Information System (INIS)

    Boyer, R.; Leblanc, M.A.R.

    1977-01-01

    The magnetic flux rotating in step with a type II superconducting disc is measured with orthogonal pick up coils for various previous magnetic histories vs H 0 applied at right angles to the axis of rotation. For some initial magnetic states, flux expulsion, independent of the rate of rotation, occurs during the initial rotation. A simple model where flux lines leave the specimen against the magnetic pressure in the active region accounts for the observations. (author)

  12. Mercury nano-trap for effective and efficient removal of mercury(II) from aqueous solution

    Science.gov (United States)

    Li, Baiyan; Zhang, Yiming; Ma, Dingxuan; Shi, Zhan; Ma, Shengqian

    2014-11-01

    Highly effective and highly efficient decontamination of mercury from aqueous media remains a serious task for public health and ecosystem protection. Here we report that this task can be addressed by creating a mercury ‘nano-trap’ as illustrated by functionalizing a high surface area and robust porous organic polymer with a high density of strong mercury chelating groups. The resultant porous organic polymer-based mercury ‘nano-trap’ exhibits a record-high saturation mercury uptake capacity of over 1,000 mg g-1, and can effectively reduce the mercury(II) concentration from 10 p.p.m. to the extremely low level of smaller than 0.4 p.p.b. well below the acceptable limits in drinking water standards (2 p.p.b.), and can also efficiently remove >99.9% mercury(II) within a few minutes. Our work therefore presents a new benchmark for mercury adsorbent materials and provides a new perspective for removing mercury(II) and also other heavy metal ions from contaminated water for environmental remediation.

  13. Cryogenic surface ion traps

    International Nuclear Information System (INIS)

    Niedermayr, M.

    2015-01-01

    Microfabricated surface traps are a promising architecture to realize a scalable quantum computer based on trapped ions. In principle, hundreds or thousands of surface traps can be located on a single substrate in order to provide large arrays of interacting ions. To this end, trap designs and fabrication methods are required that provide scalable, stable and reproducible ion traps. This work presents a novel surface-trap design developed for cryogenic applications. Intrinsic silicon is used as the substrate material of the traps. The well-developed microfabrication and structuring methods of silicon are utilized to create simple and reproducible traps. The traps were tested and characterized in a cryogenic setup. Ions could be trapped and their life time and motional heating were investigated. Long ion lifetimes of several hours were observed and the measured heating rates were reproducibly low at around 1 phonon per second at a trap frequency of 1 MHz. (author) [de

  14. Quasi-particle excitations and dynamical structure function of trapped Bose-condensates in the WKB approximation

    OpenAIRE

    Csordás, András; Graham, Robert; Szépfalusy, Péter

    1997-01-01

    The Bogoliubov equations of the quasi-particle excitations in a weakly interacting trapped Bose-condensate are solved in the WKB approximation in an isotropic harmonic trap, determining the discrete quasi-particle energies and wave functions by torus (Bohr-Sommerfeld) quantization of the integrable classical quasi-particle dynamics. The results are used to calculate the position and strengths of the peaks in the dynamic structure function which can be observed by off-resonance inelastic light...

  15. Tarantula huwentoxin-IV inhibits neuronal sodium channels by binding to receptor site 4 and trapping the domain ii voltage sensor in the closed configuration.

    Science.gov (United States)

    Xiao, Yucheng; Bingham, Jon-Paul; Zhu, Weiguo; Moczydlowski, Edward; Liang, Songping; Cummins, Theodore R

    2008-10-03

    Peptide toxins with high affinity, divergent pharmacological functions, and isoform-specific selectivity are powerful tools for investigating the structure-function relationships of voltage-gated sodium channels (VGSCs). Although a number of interesting inhibitors have been reported from tarantula venoms, little is known about the mechanism for their interaction with VGSCs. We show that huwentoxin-IV (HWTX-IV), a 35-residue peptide from tarantula Ornithoctonus huwena venom, preferentially inhibits neuronal VGSC subtypes rNav1.2, rNav1.3, and hNav1.7 compared with muscle subtypes rNav1.4 and hNav1.5. Of the five VGSCs examined, hNav1.7 was most sensitive to HWTX-IV (IC(50) approximately 26 nM). Following application of 1 microm HWTX-IV, hNav1.7 currents could only be elicited with extreme depolarizations (>+100 mV). Recovery of hNav1.7 channels from HWTX-IV inhibition could be induced by extreme depolarizations or moderate depolarizations lasting several minutes. Site-directed mutagenesis analysis indicated that the toxin docked at neurotoxin receptor site 4 located at the extracellular S3-S4 linker of domain II. Mutations E818Q and D816N in hNav1.7 decreased toxin affinity for hNav1.7 by approximately 300-fold, whereas the reverse mutations in rNav1.4 (N655D/Q657E) and the corresponding mutations in hNav1.5 (R812D/S814E) greatly increased the sensitivity of the muscle VGSCs to HWTX-IV. Our data identify a novel mechanism for sodium channel inhibition by tarantula toxins involving binding to neurotoxin receptor site 4. In contrast to scorpion beta-toxins that trap the IIS4 voltage sensor in an outward configuration, we propose that HWTX-IV traps the voltage sensor of domain II in the inward, closed configuration.

  16. Photonic Structures for Light Trapping in Thin Film Silicon Solar Cells: Design and Experiment

    Directory of Open Access Journals (Sweden)

    Yi Ding

    2017-12-01

    Full Text Available One of the foremost challenges in designing thin-film silicon solar cells (TFSC is devising efficient light-trapping schemes due to the short optical path length imposed by the thin absorber thickness. The strategy relies on a combination of a high-performance back reflector and an optimized texture surface, which are commonly used to reflect and scatter light effectively within the absorption layer, respectively. In this paper, highly promising light-trapping structures based on a photonic crystal (PC for TFSCs were investigated via simulation and experiment. Firstly, a highly-reflective one-dimensional photonic crystal (1D-PC was designed and fabricated. Then, two types of 1D-PC-based back reflectors (BRs were proposed: Flat 1D-PC with random-textured aluminum-doped zinc oxide (AZO or random-textured 1D-PC with AZO. These two newly-designed BRs demonstrated not only high reflectivity and sufficient conductivity, but also a strong light scattering property, which made them efficient candidates as the electrical contact and back reflector since the intrinsic losses due to the surface plasmon modes of the rough metal BRs can be avoided. Secondly, conical two-dimensional photonic crystal (2D-PC-based BRs were investigated and optimized for amorphous a-SiGe:H solar cells. The maximal absorption value can be obtained with an aspect ratio of 1/2 and a period of 0.75 µm. To improve the full-spectral optical properties of solar cells, a periodically-modulated PC back reflector was proposed and experimentally demonstrated in the a-SiGe:H solar cell. This periodically-modulated PC back reflector, also called the quasi-crystal structure (QCS, consists of a large periodic conical PC and a randomly-textured Ag layer with a feature size of 500–1000 nm. The large periodic conical PC enables conformal growth of the layer, while the small feature size of Ag can further enhance the light scattering. In summary, a comprehensive study of the design, simulation

  17. Structure and dynamics of highly charged heavy ions studied with the electron beam ion trap in Tokyo

    International Nuclear Information System (INIS)

    Nakamura, Nobuyuki; Hu, Zhimin; Watanabe, Hirofumi; Li, Yueming; Kato, Daiji; Currell, Fred J.; Tong Xiaomin; Watanabe, Tsutomu; Ohtani, Shunsuke

    2011-01-01

    In this paper, we present the structure and the dynamics of highly charged heavy ions studied through dielectronic recombination (DR) observations performed with the Tokyo electron beam ion trap. By measuring the energy dependence of the ion abundance ratio in the trap at equilibrium, we have observed DR processes for open shell systems very clearly. Remarkable relativistic effects due to the generalized Breit interaction have been clearly shown in DR for highly charged heavy ions. We also present the first result for the coincidence measurement of two photons emitted from a single DR event.

  18. Structural properties of MHC class II ligands, implications for the prediction of MHC class II epitopes.

    Directory of Open Access Journals (Sweden)

    Kasper Winther Jørgensen

    2010-12-01

    Full Text Available Major Histocompatibility class II (MHC-II molecules sample peptides from the extracellular space allowing the immune system to detect the presence of foreign microbes from this compartment. Prediction of MHC class II ligands is complicated by the open binding cleft of the MHC class II molecule, allowing binding of peptides extending out of the binding groove. Furthermore, only a few HLA-DR alleles have been characterized with a sufficient number of peptides (100-200 peptides per allele to derive accurate description of their binding motif. Little work has been performed characterizing structural properties of MHC class II ligands. Here, we perform one such large-scale analysis. A large set of SYFPEITHI MHC class II ligands covering more than 20 different HLA-DR molecules was analyzed in terms of their secondary structure and surface exposure characteristics in the context of the native structure of the corresponding source protein. We demonstrated that MHC class II ligands are significantly more exposed and have significantly more coil content than other peptides in the same protein with similar predicted binding affinity. We next exploited this observation to derive an improved prediction method for MHC class II ligands by integrating prediction of MHC- peptide binding with prediction of surface exposure and protein secondary structure. This combined prediction method was shown to significantly outperform the state-of-the-art MHC class II peptide binding prediction method when used to identify MHC class II ligands. We also tried to integrate N- and O-glycosylation in our prediction methods but this additional information was found not to improve prediction performance. In summary, these findings strongly suggest that local structural properties influence antigen processing and/or the accessibility of peptides to the MHC class II molecule.

  19. CHROMIUM(II) AMIDES - SYNTHESIS AND STRUCTURES

    NARCIS (Netherlands)

    EDEMA, JJH; GAMBAROTTA, S; MEETSMA, A; SPEK, AL; SMEETS, WJJ; CHIANG, MY

    1993-01-01

    A novel class of mono- and di-meric chromium(II) amides has been prepared and characterized. Reaction of [CrCl2(thf)2] (thf = tetrahydrofuran) with 2 equivalents of M(NR2) (R = C6H11, Pr(i), Ph, or phenothiazinyl; M = Li or Na) allowed the formation of the homoleptic amides [{Cr(mu-NR2)(NR2)}2] (R =

  20. Earthworm coelomocyte extracellular traps: structural and functional similarities with neutrophil NETs.

    Science.gov (United States)

    Homa, Joanna

    2018-03-01

    Invertebrate immunity is associated with natural mechanisms that include cellular and humoral elements, similar to those that play a role in vertebrate innate immune responses. Formation of extracellular traps (ETs) is a newly discovered mechanism to combat pathogens, operating not only in vertebrate leucocytes but also in invertebrate immune cells. The ET components include extracellular DNA (exDNA), antimicrobial proteins and histones. Formation of mammalian ETs depends on enzymes such as neutrophil elastase, myeloperoxidase, the citrullination of histones and protease activity. It was confirmed that coelomocytes-immunocompetent cells of the earthworm Eisenia andrei-are also able to release ETs in a protease-dependent manner, dependent or independent of the formation of reactive oxygen species and rearrangement of the cell cytoskeleton. Similar to vertebrate leukocytes (e.g., neutrophil), coelomocytes are responsible for many immune functions like phagocytosis, cytotoxicity and secretion of humoral factors. ETs formed by coelomocyte analogues to neutrophil ETs consist of exDNA, histone H3 and attached to these structures proteins, e.g., heat shock proteins HSP27. The latter fact confirms that mechanisms of ET release are conserved in evolution. The study on Annelida adds this animal group to the list of invertebrates capable of ET release, but most importantly provides insides into innate mechanisms of ET formation in lower animal taxa.

  1. Composite Structure Monitoring using Direct Write Sensors, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — This NASA SBIR Phase II project seeks to develop and demonstrate a suite of sensor products to monitor the health of composite structures. Sensors will be made using...

  2. Shape Memory Alloy-Based Periodic Cellular Structures, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR Phase II effort will continue to develop and demonstrate an innovative shape memory alloy (SMA) periodic cellular structural technology. Periodic cellular...

  3. Collimated-hole structures as efficient differential pumping barrier, one-way valve and tool for aligning Penning traps

    International Nuclear Information System (INIS)

    Kluge, H.-Jürgen; Block, Michael; Herfurth, Frank

    2011-01-01

    A collimated-hole structure consists of a very large number of parallel channels which have each a very small diameter and are closely packed together. Such devices, installed in vacuum systems allow one to separate regions of very different gas pressures. A collimated-hole structure has high transmission for a directed ion beam with low emittance but a very low conductance for rest gas atoms or molecules exhibiting random walk. Therefore it is proposed to use such a structure as one-way valve and/or efficient differential pumping barrier in set-ups using Penning traps. Furthermore, these devices might be very useful to align the axis of a Penning trap with the direction of the magnetic field lines which is essential to avoid systematic uncertainties in high-accuracy mass spectroscopy.

  4. NONA Cure of Prepreg Structures, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — CRG's no-oven, no-autoclave (NONA) cure of OoA or autoclave prepreg materials allows the manufacture of large composite structures without the expensive and...

  5. Optimizing the structure of Tetracyanoplatinate(II)

    DEFF Research Database (Denmark)

    Dohn, Asmus Ougaard; Møller, Klaus Braagaard; Sauer, Stephan P. A.

    2013-01-01

    . For the C-N bond these trends are reversed and an order of magnitude smaller. With respect to the basis set dependence we observed that a triple zeta basis set with polarization functions gives in general sufficiently converged results, but while for the Pt-C bond it is advantageous to include extra diffuse......The geometry of tetracyanoplatinate(II) (TCP) has been optimized with density functional theory (DFT) calculations in order to compare different computational strategies. Two approximate scalar relativistic methods, i.e. the scalar zeroth-order regular approximation (ZORA) and non...... is almost quantitatively reproduced in the ZORA and ECP calculations. In addition, the effect of the exchange-correlation functional and one-electron basis set was studied by employing the two generalized gradient approximation (GGA) functionals, BLYP and PBE, as well as their hybrid version B3LYP and PBE0...

  6. Numerical simulation of crosstalk in reduced pitch HgCdTe photon-trapping structure pixel arrays.

    Science.gov (United States)

    Schuster, Jonathan; Bellotti, Enrico

    2013-06-17

    We have investigated crosstalk in HgCdTe photovoltaic pixel arrays employing a photon trapping (PT) structure realized with a periodic array of pillars intended to provide broadband operation. We have found that, compared to non-PT pixel arrays with similar geometry, the array employing the PT structure has a slightly higher optical crosstalk. However, when the total crosstalk is evaluated, the presence of the PT region drastically reduces the total crosstalk; making the use of the PT structure not only useful to obtain broadband operation, but also desirable for reducing crosstalk in small pitch detector arrays.

  7. Profile structures of TJ-II stellarator plasmas

    NARCIS (Netherlands)

    Herranz, J.; Pastor, I.; Castejon, F.; de la Luna, E.; Garcia-Cortes, I.; Barth, C. J.; Ascasibar, E.; Sanchez, J.; Tribaldos, V.

    2000-01-01

    Fine structures are found in the TJ-II stellarator electron temperature and density profiles, when they are measured using a high spatial resolution Thomson scattering system. These structures consist of peaks and valleys superimposed to a smooth average. Some irregularities remain in an ensemble

  8. Structural basis for hyperactivity of cN-II mutants

    Czech Academy of Sciences Publication Activity Database

    Hnízda, Aleš; Škerlová, Jana; Šinalová, Martina; Pachl, Petr; Man, Petr; Novák, Petr; Fábry, Milan; Řezáčová, Pavlína; Veverka, Václav

    2015-01-01

    Roč. 22, č. 1 (2015), s. 4 ISSN 1211-5894. [Discussions in Structural Molecular Biology. Annual Meeting of the Czech Society for Structural Biology /13./. 19.03.2015-21.03.2015, Nové Hrady] Institutional support: RVO:61388963 ; RVO:68378050 ; RVO:61388971 Keywords : cN-II mutants * enzyme hyperactivity Subject RIV: CE - Biochemistry

  9. Tunable superconducting resonators with integrated trap structures for coupling with ultracold atomic gases

    Energy Technology Data Exchange (ETDEWEB)

    Ferdinand, Benedikt; Wiedmaier, Dominik; Koelle, Dieter; Kleiner, Reinhold [Physikalisches Institut and Center for Quantum Science in LISA+, Universitaet Tuebingen (Germany); Bothner, Daniel [Physikalisches Institut and Center for Quantum Science in LISA+, Universitaet Tuebingen (Germany); Kavli Institute of Nanoscience, Delft University of Technology, Delft (Netherlands)

    2016-07-01

    We intend to investigate a hybrid quantum system where ultracold atomic gases play the role of a long-living quantum memory, coupled to a superconducting qubit via a coplanar waveguide transmission line resonator. As a first step we developed a resonator chip containing a Z-shaped trapping wire for the atom trap. In order to suppress parasitic resonances due to stray capacitances, and to achieve good ground connection we use hybrid superconductor - normal conductor chips. As an additional degree of freedom we add a ferroelectric capacitor making the resonators voltage-tunable. We furthermore show theoretical results on the expected coupling strength between resonator and atomic cloud.

  10. Primary volcanic structures from a type section of Deccan Trap flows ...

    Indian Academy of Sciences (India)

    Swanson 1967; Macdonald 1967; Long and Wood. Keywords. Deccan Traps; lava flows; volcanism; isotherm; cooling history. J. Earth Syst. Sci. 115, No. ...... Kilauea Volcanic island of Hawaii; J. Geophys. Res. 103. 27,303–27,323. Lightfoot ...

  11. Vision feedback driven automated assembly of photopolymerized structures by parallel optical trapping and manipulation

    DEFF Research Database (Denmark)

    Dam, Jeppe Seidelin; Perch-Nielsen, Ivan Ryberg; Rodrigo, Peter John

    2007-01-01

    We demonstrate how optical trapping and manipulation can be used to assemble microstructures. The microstructures we show being automatically recognized and manipulated are produced using the two-photon polymerization (2PP) technique with submicron resolution. In this work, we show identical shape...

  12. Spectroscopy of a Synthetic Trapped Ion Qubit

    Science.gov (United States)

    Hucul, David; Christensen, Justin E.; Hudson, Eric R.; Campbell, Wesley C.

    2017-09-01

    133Ba+ has been identified as an attractive ion for quantum information processing due to the unique combination of its spin-1 /2 nucleus and visible wavelength electronic transitions. Using a microgram source of radioactive material, we trap and laser cool the synthetic A =133 radioisotope of barium II in a radio-frequency ion trap. Using the same, single trapped atom, we measure the isotope shifts and hyperfine structure of the 62P1 /2↔62S1 /2 and 62P1 /2↔52D3 /2 electronic transitions that are needed for laser cooling, state preparation, and state detection of the clock-state hyperfine and optical qubits. We also report the 62P1 /2↔52D3 /2 electronic transition isotope shift for the rare A =130 and 132 barium nuclides, completing the spectroscopic characterization necessary for laser cooling all long-lived barium II isotopes.

  13. Structure and reactivity of a mononuclear gold(II) complex

    Science.gov (United States)

    Preiß, Sebastian; Förster, Christoph; Otto, Sven; Bauer, Matthias; Müller, Patrick; Hinderberger, Dariush; Hashemi Haeri, Haleh; Carella, Luca; Heinze, Katja

    2017-12-01

    Mononuclear gold(II) complexes are very rare labile species. Transient gold(II) species have been suggested in homogeneous catalysis and in medical applications, but their geometric and electronic structures have remained essentially unexplored: even fundamental data, such as the ionic radius of gold(II), are unknown. Now, an unprecedentedly stable neutral gold(II) complex of a porphyrin derivative has been isolated, and its structural and spectroscopic features determined. The gold atom adopts a 2+2 coordination mode in between those of gold(III) (four-coordinate square planar) and gold(I) (two-coordinate linear), owing to a second-order Jahn-Teller distortion enabled by the relativistically lowered 6s orbital of gold. The reactivity of this gold(II) complex towards dioxygen, nitrosobenzene and acids is discussed. This study provides insight on the ionic radius of gold(II), and allows it to be placed within the homologous series of nd9 Cu/Ag/Au divalent ions and the 5d8/9/10 Pt/Au/Hg 'relativistic' triad in the periodic table.

  14. 2.4 Å resolution crystal structure of human TRAP1 NM , the Hsp90 paralog in the mitochondrial matrix

    Energy Technology Data Exchange (ETDEWEB)

    Sung, Nuri; Lee, Jungsoon; Kim, Ji-Hyun; Chang, Changsoo; Tsai, Francis T. F.; Lee, Sukyeong

    2016-07-13

    TRAP1 is an organelle-specific Hsp90 paralog that is essential for neoplastic growth. As a member of the Hsp90 family, TRAP1 is presumed to be a general chaperone facilitating the late-stage folding of Hsp90 client proteins in the mitochondrial matrix. Interestingly, TRAP1 cannot replace cytosolic Hsp90 in protein folding, and none of the known Hsp90 co-chaperones are found in mitochondria. Thus, the three-dimensional structure of TRAP1 must feature regulatory elements that are essential to the ATPase activity and chaperone function of TRAP1. Here, the crystal structure of a human TRAP1NMdimer is presented, featuring an intact N-domain and M-domain structure, bound to adenosine 5'-β,γ-imidotriphosphate (ADPNP). The crystal structure together with epitope-mapping results shows that the TRAP1 M-domain loop 1 contacts the neighboring subunit and forms a previously unobserved third dimer interface that mediates the specific interaction with mitochondrial Hsp70.

  15. 2.4 Å resolution crystal structure of human TRAP1NM, the Hsp90 paralog in the mitochondrial matrix.

    Science.gov (United States)

    Sung, Nuri; Lee, Jungsoon; Kim, Ji Hyun; Chang, Changsoo; Tsai, Francis T F; Lee, Sukyeong

    2016-08-01

    TRAP1 is an organelle-specific Hsp90 paralog that is essential for neoplastic growth. As a member of the Hsp90 family, TRAP1 is presumed to be a general chaperone facilitating the late-stage folding of Hsp90 client proteins in the mitochondrial matrix. Interestingly, TRAP1 cannot replace cytosolic Hsp90 in protein folding, and none of the known Hsp90 co-chaperones are found in mitochondria. Thus, the three-dimensional structure of TRAP1 must feature regulatory elements that are essential to the ATPase activity and chaperone function of TRAP1. Here, the crystal structure of a human TRAP1NM dimer is presented, featuring an intact N-domain and M-domain structure, bound to adenosine 5'-β,γ-imidotriphosphate (ADPNP). The crystal structure together with epitope-mapping results shows that the TRAP1 M-domain loop 1 contacts the neighboring subunit and forms a previously unobserved third dimer interface that mediates the specific interaction with mitochondrial Hsp70.

  16. Universal fine structure of the specific heat at the critical λ-point for an ideal Bose gas in an arbitrary trap

    International Nuclear Information System (INIS)

    Tarasov, S V; Kocharovsky, Vl V; Kocharovsky, V V

    2014-01-01

    We analytically find the universal fine structure of the noted discontinuity in the value and/or derivative of the specific heat of an ideal Bose gas in an arbitrary trap in the whole critical region around the λ-point of the Bose–Einstein condensation. The result reveals a remarkable dependence of the λ-point structure on the trap's form and boundary conditions, even for a macroscopically large system. We suggest measuring this strong effect in the experiments with a controllable trap potential. (paper)

  17. Evidence for charge-trapping inducing polymorphic structural-phase transition in pentacene.

    Science.gov (United States)

    Ando, Masahiko; Kehoe, Tom B; Yoneya, Makoto; Ishii, Hiroyuki; Kawasaki, Masahiro; Duffy, Claudia M; Minakata, Takashi; Phillips, Richard T; Sirringhaus, Henning

    2015-01-07

    Trapped-charge-induced transformation of pentacene polymorphs is observed by using in situ Raman spectroscopy and molecular dynamics simulations reveal that the charge should be localized in pentacene molecules at the interface with static intermolecular disorder along the long axis. Quantum chemical calculations of the intermolecular transfer integrals suggest the disorder to be large enough to induce Anderson-type localization. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Structure and membrane organization of photosystem II in green plants

    NARCIS (Netherlands)

    Hankamer, B; Barber, J; Boekema, EJ

    1997-01-01

    Photosystem II (PSII) is the pigment protein complex embedded in the thylakoid membrane of higher plants, algae, and cyanobacteria that uses solar energy to drive the photosynthetic water-splitting reaction. This chapter reviews the primary, secondary, tertiary, and quaternary structures of PSII as

  19. Enhanced vaccine-induced CD8+ T cell responses to malaria antigen ME-TRAP by fusion to MHC class ii invariant chain.

    Directory of Open Access Journals (Sweden)

    Alexandra J Spencer

    Full Text Available The orthodox role of the invariant chain (CD74; Ii is in antigen presentation to CD4+ T cells, but enhanced CD8+ T cells responses have been reported after vaccination with vectored viral vaccines encoding a fusion of Ii to the antigen of interest. In this study we assessed whether fusion of the malarial antigen, ME-TRAP, to Ii could increase the vaccine-induced CD8+ T cell response. Following single or heterologous prime-boost vaccination of mice with a recombinant chimpanzee adenovirus vector, ChAd63, or recombinant modified vaccinia virus Ankara (MVA, higher frequencies of antigen-specific CD4+ and CD8+ T cells were observed, with the largest increases observed following a ChAd63-MVA heterologous prime-boost regimen. Studies in non-human primates confirmed the ability of Ii-fusion to augment the T cell response, where a 4-fold increase was maintained up to 11 weeks after the MVA boost. Of the numerous different approaches explored to increase vectored vaccine induced immunogenicity over the years, fusion to the invariant chain showed a consistent enhancement in CD8+ T cell responses across different animal species and may therefore find application in the development of vaccines against human malaria and other diseases where high levels of cell-mediated immunity are required.

  20. Energy Levels, wavelengths and hyperfine structure measurements of Sc II

    Science.gov (United States)

    Hala, Fnu; Nave, Gillian

    2018-01-01

    Lines of singly ionized Scandium (Sc II) along with other Iron group elements have been observed [1] in the region surrounding the massive star Eta Carinae [2,3] called the strontium filament (SrF). The last extensive analysis of Sc II was the four-decade old work of Johansson & Litzen [4], using low-resolution grating spectroscopy. To update and extend the Sc II spectra, we have made observation of Sc/Ar, Sc/Ne and Sc/Ge/Ar hollow cathode emission spectrum on the NIST high resolution FT700 UV/Vis and 2 m UV/Vis/IR Fourier transform spectrometers (FTS). More than 850 Sc II lines have been measured in the wavelength range of 187 nm to 3.2 μm. connecting a total of 152 energy levels. The present work also focuses to resolve hyperfine structure (HFS) in Sc II lines. We aim to obtain accurate transition wavelengths, improved energy levels and HFS constants of Sc II. The latest results from work in progress will be presented.Reference[1] Hartman H, Gull T, Johansson S and Smith N 2004 Astron. Astrophys. 419 215[2] Smith N, Morse J A and Gull T R 2004 Astrophys. J. 605 405[3] Davidson K and Humphreys R M 1997 Annu. Rev. Astron. Astrophys. 35[4] Johansson S and Litzén U 1980 Phys. Scr. 22 49

  1. High precision measurements of hyperfine structure in Tm II, N2+ and Sc II

    International Nuclear Information System (INIS)

    Mansour, N.B.; Dinneen, T.P.; Young, L.

    1988-01-01

    We have applied the technique of collinear fast-ion-beam laser spectroscopy to measure the hyperfine structure (hfs) in Sc II, Tm II and N 2 + . Laser induced fluorescence was observed from a 50 keV ion beam which was superimposed with the output of an actively stabilized ring dye laser (rms bandwidth 2 and the excited 3d4p configuration of Sc II and in the 4f 13 6s and 4f 13 5d configurations of the Tm II. The fine and hyperfine structure of N 2 + has been observed in the (0,1) and (1,2) band of B 2 Σ/sub u/ + /minus/X 2 Σ/sub g/ + system. Higher resolution measurements of the metastable 3d 2 configuration in Sc II were also made by laser-rf double resonance. The experimental results will be compared with those obtained by multiconfiguration Hartree-Fock ab-initio calculations. 15 refs., 4 figs., 5 tabs

  2. Electrochemical, spectroscopic, and photophysical properties of structurally diverse polyazine-bridged Ru(II),Pt(II) and Os(II),Ru(II),Pt(II) supramolecular motifs.

    Science.gov (United States)

    Knoll, Jessica D; Arachchige, Shamindri M; Wang, Guangbin; Rangan, Krishnan; Miao, Ran; Higgins, Samantha L H; Okyere, Benjamin; Zhao, Meihua; Croasdale, Paul; Magruder, Katherine; Sinclair, Brian; Wall, Candace; Brewer, Karen J

    2011-09-19

    Five new tetrametallic supramolecules of the motif [{(TL)(2)M(dpp)}(2)Ru(BL)PtCl(2)](6+) and three new trimetallic light absorbers [{(TL)(2)M(dpp)}(2)Ru(BL)](6+) (TL = bpy = 2,2'-bipyridine or phen = 1,10-phenanthroline; M = Ru(II) or Os(II); BL = dpp = 2,3-bis(2-pyridyl)pyrazine, dpq = 2,3-bis(2-pyridyl)quinoxaline, or bpm = 2,2'-bipyrimidine) were synthesized and their redox, spectroscopic, and photophysical properties investigated. The tetrametallic complexes couple a Pt(II)-based reactive metal center to Ru and/or Os light absorbers through two different polyazine BL to provide structural diversity and interesting resultant properties. The redox potential of the M(II/III) couple is modulated by M variation, with the terminal Ru(II/III) occurring at 1.58-1.61 V and terminal Os(II/III) couples at 1.07-1.18 V versus Ag/AgCl. [{(TL)(2)M(dpp)}(2)Ru(BL)](PF(6))(6) display terminal M(dπ)-based highest occupied molecular orbitals (HOMOs) with the dpp(π*)-based lowest unoccupied molecular orbital (LUMO) energy relatively unaffected by the nature of BL. The coupling of Pt to the BL results in orbital inversion with localization of the LUMO on the remote BL in the tetrametallic complexes, providing a lowest energy charge separated (CS) state with an oxidized terminal Ru or Os and spatially separated reduced BL. The complexes [{(TL)(2)M(dpp)}(2)Ru(BL)](6+) and [{(TL)(2)M(dpp)}(2)Ru(BL)PtCl(2)](6+) efficiently absorb light throughout the UV and visible regions with intense metal-to-ligand charge transfer (MLCT) transitions in the visible at about 540 nm (M = Ru) and 560 nm (M = Os) (ε ≈ 33,000-42,000 M(-1) cm(-1)) and direct excitation to the spin-forbidden (3)MLCT excited state in the Os complexes about 720 nm. All the trimetallic and tetrametallic Ru-based supramolecular systems emit from the terminal Ru(dπ)→dpp(π*) (3)MLCT state, λ(max)(em) ≈ 750 nm. The tetrametallic systems display complex excited state dynamics with quenching of the (3)MLCT emission at

  3. Nano-Photonic Structures for Light Trapping in Ultra-Thin Crystalline Silicon Solar Cells

    Directory of Open Access Journals (Sweden)

    Prathap Pathi

    2017-01-01

    Full Text Available Thick wafer-silicon is the dominant solar cell technology. It is of great interest to develop ultra-thin solar cells that can reduce materials usage, but still achieve acceptable performance and high solar absorption. Accordingly, we developed a highly absorbing ultra-thin crystalline Si based solar cell architecture using periodically patterned front and rear dielectric nanocone arrays which provide enhanced light trapping. The rear nanocones are embedded in a silver back reflector. In contrast to previous approaches, we utilize dielectric photonic crystals with a completely flat silicon absorber layer, providing expected high electronic quality and low carrier recombination. This architecture creates a dense mesh of wave-guided modes at near-infrared wavelengths in the absorber layer, generating enhanced absorption. For thin silicon (<2 μm and 750 nm pitch arrays, scattering matrix simulations predict enhancements exceeding 90%. Absorption approaches the Lambertian limit at small thicknesses (<10 μm and is slightly lower (by ~5% at wafer-scale thicknesses. Parasitic losses are ~25% for ultra-thin (2 μm silicon and just 1%–2% for thicker (>100 μm cells. There is potential for 20 μm thick cells to provide 30 mA/cm2 photo-current and >20% efficiency. This architecture has great promise for ultra-thin silicon solar panels with reduced material utilization and enhanced light-trapping.

  4. Discourse, Paragraph, and Sentence Structure in Selected Philippine Languages. Final Report. Volume II, Sentence Structure.

    Science.gov (United States)

    Longacre, Robert E.

    Volume II of "Discourse, Paragraph, and Sentence Structure in Selected Philippine Languages" begins with an explanation of certain assumptions and postulates regarding sentence structure. A detailed treatment of systems of sentence structure and the parameters of such systems follows. Data in the various indigenous languages are…

  5. Moessbauer spectroscopic study on valence-detrapping and trapping of mixed-valence trinuclear iron (III, III, II) fluorine-substitute benzoate complexes

    International Nuclear Information System (INIS)

    Sakai, Y.; Onaka, S.; Ogiso, R.; Takayama, T.; Takahashi, M.; Nakamoto, T.

    2012-01-01

    Four mixed-valence trinuclear iron(III, III, II) fluorine-substituted benzoate complexes were synthesized; Fe 3 O(C 6 F 5 COO) 6 (C 5 H 5 N) 3 ·CH 2 Cl 2 (1), Fe 3 O(C 6 F 5 COO) 6 (C 5 H 5 N) 3 (2), Fe 3 O(2H-C 6 F 4 COO) 6 (C 5 H 5 N) 3 (3), and Fe 3 O(4H-C 6 F 4 COO) 6 (C 5 H 5 N) 3 (4). By means of 57 Fe-Moessbauer spectroscopy, valence-detrapping and trapping phenomena have been investigated for the four mixed-valence complexes. The valence state of three iron ions is trapped at lower temperatures while it is fully detrapped at higher temperatures for 1. Valence detrapping is not observed for 2, 3, and 4 even at room temperature, although Moessbauer spectra for 3 and 4 show a complicated temperature dependence. (author)

  6. A collapsin response mediator protein 2 isoform controls myosin II-mediated cell migration and matrix assembly by trapping ROCK II

    DEFF Research Database (Denmark)

    Yoneda, Atsuko; Morgan-Fisher, Marie; Wait, Robin

    2012-01-01

    Collapsin response mediator protein 2 (CRMP-2) is known as a regulator of neuronal polarity and differentiation through microtubule assembly and trafficking. Here, we show that CRMP-2 is ubiquitously expressed and a splice variant (CRMP-2L), which is expressed mainly in epithelial cells among...... nonneuronal cells, regulates myosin II-mediated cellular functions, including cell migration. While the CRMP-2 short form (CRMP-2S) is recognized as a substrate of the Rho-GTP downstream kinase ROCK in neuronal cells, a CRMP-2 complex containing 2L not only bound the catalytic domain of ROCK II through two......-2L but not -2S inhibited fibronectin matrix assembly in fibroblasts. Underlying these responses, CRMP-2L regulated the kinase activity of ROCK II but not ROCK I, independent of GTP-RhoA levels. This study provides a new insight into CRMP-2 as a controller of myosin II-mediated cellular functions...

  7. Oxygen trapped by rare earth tetrahedral clusters in Nd4FeOS6: Crystal structure, electronic structure, and magnetic properties

    International Nuclear Information System (INIS)

    Lin, Qisheng; Taufour, Valentin; Zhang, Yuemei; Wood, Max; Drtina, Thomas; Bud’ko, Sergey L.; Canfield, Paul C.; Miller, Gordon J.

    2015-01-01

    Single crystals of Nd 4 FeOS 6 were grown from an Fe–S eutectic solution. Single crystal X-ray diffraction analysis revealed a Nd 4 MnOSe 6 -type structure (P6 3 mc, a=9.2693(1) Å, c=6.6650(1)Å, V=495.94(1) Å 3 , Z=2), featuring parallel chains of face-sharing [FeS 6×1/2 ] 4− trigonal antiprisms and interlinked [Nd 4 OS 3 ] 4+ cubane-like clusters. Oxygen atoms were found to be trapped by Nd 4 clusters in the [Nd 4 OS 3 ] 4 + chains. Structural differences among Nd 4 MnOSe 6 -type Nd 4 FeOS 6 and the related La 3 CuSiS 7 − and Pr 8 CoGa 3 -type structures have been described. Magnetic susceptibility measurements on Nd 4 FeOS 6 suggested the dominance of antiferromagnetic interactions at low temperature, but no magnetic ordering down to 2 K was observed. Spin-polarized electronic structure calculations revealed magnetic frustration with dominant antiferromagnetic interactions. - Graphical abstract: Trapping of oxygen in Nd 4 tetrahedral clusters results in the formation of the Nd 4 MnOSe 6 -type Nd 4 FeOS 6 , in contrast to the La 3 CuSiS 7 -type oxygen-free Nd 4 FeS 7 and related Pr 8 CoGa 3 -type structures. Complex magnetic frustration inhibits magnetic ordering at low temperature. - Highlights: • Single crystals of Nd 4 FeOS 6 were grown using self-flux method. • Oxygen was found trapped by Nd 4 tetrahedral clusters. • Comparison with two closely related structural types were discussed. • Magnetic measurements revealed antiferromagnetic (AFM) interaction. • VASP calculations confirmed strong magnetic frustration in AFM model

  8. Hyperfine Structure and Isotope Shifts in Dy II

    Directory of Open Access Journals (Sweden)

    Dylan F. Del Papa

    2017-01-01

    Full Text Available Using fast-ion-beam laser-fluorescence spectroscopy (FIBLAS, we have measured the hyperfine structure (hfs of 14 levels and an additional four transitions in Dy II and the isotope shifts (IS of 12 transitions in the wavelength range of 422–460 nm. These are the first precision measurements of this kind in Dy II. Along with hfs and IS, new undocumented transitions were discovered within 3 GHz of the targeted transitions. These atomic data are essential for astrophysical studies of chemical abundances, allowing correction for saturation and the effects of blended lines. Lanthanide abundances are important in diffusion modeling of stellar interiors, and in the mechanisms and history of nucleosynthesis in the universe. Hfs and IS also play an important role in the classification of energy levels, and provide a benchmark for theoretical atomic structure calculations.

  9. Incommensurate composite crystal structure of scandium-II

    International Nuclear Information System (INIS)

    Fujihisa, Hiroshi; Gotoh, Yoshito; Yamawaki, Hiroshi; Sakashita, Mami; Takeya, Satoshi; Honda, Kazumasa; Akahama, Yuichi; Kawamura, Haruki

    2005-01-01

    The long-unknown crystal structure of the high pressure phase scandium-II was solved by powder x-ray diffraction and was found to have tetragonal host channels along the c axis and guest chains that are incommensurate with the host, as well as the high pressure phases of Ba, Sr, Bi, and Sb. The pressure dependences of the lattice constants, the incommensurability, the atomic distances, and the atomic volume were investigated

  10. Crystal structure of bis(4-acetylanilinium tetrachloridocobaltate(II

    Directory of Open Access Journals (Sweden)

    Manickam Thairiyaraja

    2015-12-01

    Full Text Available The structure of the title salt, (C8H10NO2[CoCl4], is isotypic with the analogous cuprate(II structure. The asymmetric unit contains one 4-acetylanilinium cation and one half of a tetrachloridocobaltate(II anion for which the CoII atom and two Cl− ligands lie on a mirror plane. The Co—Cl distances in the distorted tetrahedral anion range from 2.2519 (6 to 2.2954 (9 Å and the Cl—Co—Cl angles range from 106.53 (2 to 110.81 (4°. In the crystal, cations are self-assembled by intermolecular N—H...O hydrogen-bonding interactions, leading to a C(8 chain motif with the chains running parallel to the b axis. π–π stacking interactions between benzene rings, with a centroid-to-centroid distance of 3.709 Å, are also observed along this direction. The CoCl42− anions are sandwiched between the cationic chains and interact with each other through intermolecular N—H...Cl hydrogen-bonding interactions, forming a three-dimensional network structure.

  11. Trapping of superoxido cobalt and peroxido dicobalt species formed reversibly from CoII and O2.

    Science.gov (United States)

    Corona, Teresa; Padamati, Sandeep K; Acuña-Parés, Ferran; Duboc, Carole; Browne, Wesley R; Company, Anna

    2017-08-22

    The formation and spectroscopic characterization of a superoxido cobalt(iii) and a peroxido dicobalt(iii) species formed in the temperature dependent reversible reaction of a cobalt(ii) precursor with O 2 is described. The electronic nature of each species is explored in their reactivity with organic substrates.

  12. Numerical simulation of quantum efficiency and surface recombination in HgCdTe IR photon-trapping structures

    Science.gov (United States)

    Schuster, Jonathan; Bellotti, Enrico

    2013-06-01

    We have investigated the quantum effiency in HgCdTe photovoltaic pixel arrays employing a photon-trapping structure realized with a periodic array of pillars intended to provide broadband operation. We have found that the quantum efficiency depends heavily on the passivation of the pillar surface. Pillars passivated with anodicoxide have a large fixed positive charge on the pillar surface. We use our three-dimensional numerical simulation model to study the effect of surface charge and surface recombination velocity on the exterior of the pillars. We then evaluate the quantum efficiency of this structure subject to different surface conditions. We have found that by themselves, the surface charge and surface recombination are detrimental to the quantum efficiency but the quantum efficiency is recovered when both phenomena are present. We will discuss the effects of these phenomena and the trade offs that exist between the two.

  13. Structure Learning and Statistical Estimation in Distribution Networks - Part II

    Energy Technology Data Exchange (ETDEWEB)

    Deka, Deepjyoti [Univ. of Texas, Austin, TX (United States); Backhaus, Scott N. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Chertkov, Michael [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-02-13

    Limited placement of real-time monitoring devices in the distribution grid, recent trends notwithstanding, has prevented the easy implementation of demand-response and other smart grid applications. Part I of this paper discusses the problem of learning the operational structure of the grid from nodal voltage measurements. In this work (Part II), the learning of the operational radial structure is coupled with the problem of estimating nodal consumption statistics and inferring the line parameters in the grid. Based on a Linear-Coupled(LC) approximation of AC power flows equations, polynomial time algorithms are designed to identify the structure and estimate nodal load characteristics and/or line parameters in the grid using the available nodal voltage measurements. Then the structure learning algorithm is extended to cases with missing data, where available observations are limited to a fraction of the grid nodes. The efficacy of the presented algorithms are demonstrated through simulations on several distribution test cases.

  14. Deuterium trapping in tungsten

    Science.gov (United States)

    Poon, Michael

    irradiation. Deuterium trapping could be characterized by three regimes: (i) enhanced D retention in a graphitic film formed by the C+ irradiation; (ii) decreased D retention in a modified tungsten-carbon layer; and (iii) D retention in pure tungsten.

  15. Deuterium trapping in tungsten

    International Nuclear Information System (INIS)

    Poon, M.

    2004-01-01

    irradiation Deuterium trapping could be characterized by three regimes: (i) enhanced D retention in a graphitic film formed by the C + irradiation ; (ii) decreased D retention in a modified tungsten-carbon layer; and (iii) D retention in pure tungsten. (author)

  16. Deuterium trapping in tungsten

    Energy Technology Data Exchange (ETDEWEB)

    Poon, M

    2004-07-01

    irradiation Deuterium trapping could be characterized by three regimes: (i) enhanced D retention in a graphitic film formed by the C{sup +} irradiation ; (ii) decreased D retention in a modified tungsten-carbon layer; and (iii) D retention in pure tungsten. (author)

  17. Integration of single oocyte trapping, in vitro fertilization and embryo culture in a microwell-structured microfluidic device.

    Science.gov (United States)

    Han, Chao; Zhang, Qiufang; Ma, Rui; Xie, Lan; Qiu, Tian; Wang, Lei; Mitchelson, Keith; Wang, Jundong; Huang, Guoliang; Qiao, Jie; Cheng, Jing

    2010-11-07

    In vitro fertilization (IVF) therapy is an important treatment for human infertility. However, the methods for clinical IVF have only changed slightly over decades: culture medium is held in oil-covered drops in Petri dishes and manipulation occurs by manual pipetting. Here we report a novel microwell-structured microfluidic device that integrates single oocyte trapping, fertilization and subsequent embryo culture. A microwell array was used to capture and hold individual oocytes during the flow-through process of oocyte and sperm loading, medium substitution and debris cleaning. Different microwell depths were compared by computational modeling and flow washing experiments for their effectiveness in oocyte trapping and debris removal. Fertilization was achieved in the microfluidic devices with similar fertilization rates to standard oil-covered drops in Petri dishes. Embryos could be cultured to blastocyst stages in our devices with developmental status individually monitored and tracked. The results suggest that the microfluidic device may bring several advantages to IVF practices by simplifying oocyte handling and manipulation, allowing rapid and convenient medium changing, and enabling automated tracking of any single embryo development.

  18. Crystal structure of bis(4-acetylanilinium tetrachloridomercurate(II

    Directory of Open Access Journals (Sweden)

    Manickam Thairiyaraja

    2015-12-01

    Full Text Available The structure of the title salt, (C8H10NO2[HgCl4], is isotypic with that of the cuprate(II and cobaltate(II analogues. The asymmetric unit contains one 4-acetylanilinium cation and one half of a tetrachloridomercurate(II anion (point group symmetry m. The Hg—Cl distances are in the range 2.4308 (7–2.5244 (11 Å and the Cl—Hg—Cl angles in the range of 104.66 (2–122.94 (4°, indicating a considerable distortion of the tetrahedral anion. In the crystal, cations are linked by an intermolecular N—H...O hydrogen-bonding interaction, leading to a C(8 chain motif with the chains extending parallel to the b axis. There is also a π–π stacking interaction with a centroid-to-centroid distance of 3.735 (2 Å between neighbouring benzene rings along this direction. The anions lie between the chains and interact with the cations through intermolecular N—H...Cl hydrogen bonds, leading to the formation of a three-dimensional network structure.

  19. Structure of photosystem II and substrate binding at room temperature.

    Science.gov (United States)

    Young, Iris D; Ibrahim, Mohamed; Chatterjee, Ruchira; Gul, Sheraz; Fuller, Franklin; Koroidov, Sergey; Brewster, Aaron S; Tran, Rosalie; Alonso-Mori, Roberto; Kroll, Thomas; Michels-Clark, Tara; Laksmono, Hartawan; Sierra, Raymond G; Stan, Claudiu A; Hussein, Rana; Zhang, Miao; Douthit, Lacey; Kubin, Markus; de Lichtenberg, Casper; Long Vo, Pham; Nilsson, Håkan; Cheah, Mun Hon; Shevela, Dmitriy; Saracini, Claudio; Bean, Mackenzie A; Seuffert, Ina; Sokaras, Dimosthenis; Weng, Tsu-Chien; Pastor, Ernest; Weninger, Clemens; Fransson, Thomas; Lassalle, Louise; Bräuer, Philipp; Aller, Pierre; Docker, Peter T; Andi, Babak; Orville, Allen M; Glownia, James M; Nelson, Silke; Sikorski, Marcin; Zhu, Diling; Hunter, Mark S; Lane, Thomas J; Aquila, Andy; Koglin, Jason E; Robinson, Joseph; Liang, Mengning; Boutet, Sébastien; Lyubimov, Artem Y; Uervirojnangkoorn, Monarin; Moriarty, Nigel W; Liebschner, Dorothee; Afonine, Pavel V; Waterman, David G; Evans, Gwyndaf; Wernet, Philippe; Dobbek, Holger; Weis, William I; Brunger, Axel T; Zwart, Petrus H; Adams, Paul D; Zouni, Athina; Messinger, Johannes; Bergmann, Uwe; Sauter, Nicholas K; Kern, Jan; Yachandra, Vittal K; Yano, Junko

    2016-12-15

    Light-induced oxidation of water by photosystem II (PS II) in plants, algae and cyanobacteria has generated most of the dioxygen in the atmosphere. PS II, a membrane-bound multi-subunit pigment protein complex, couples the one-electron photochemistry at the reaction centre with the four-electron redox chemistry of water oxidation at the Mn 4 CaO 5 cluster in the oxygen-evolving complex (OEC). Under illumination, the OEC cycles through five intermediate S-states (S 0 to S 4 ), in which S 1 is the dark-stable state and S 3 is the last semi-stable state before O-O bond formation and O 2 evolution. A detailed understanding of the O-O bond formation mechanism remains a challenge, and will require elucidation of both the structures of the OEC in the different S-states and the binding of the two substrate waters to the catalytic site. Here we report the use of femtosecond pulses from an X-ray free electron laser (XFEL) to obtain damage-free, room temperature structures of dark-adapted (S 1 ), two-flash illuminated (2F; S 3 -enriched), and ammonia-bound two-flash illuminated (2F-NH 3 ; S 3 -enriched) PS II. Although the recent 1.95 Å resolution structure of PS II at cryogenic temperature using an XFEL provided a damage-free view of the S 1 state, measurements at room temperature are required to study the structural landscape of proteins under functional conditions, and also for in situ advancement of the S-states. To investigate the water-binding site(s), ammonia, a water analogue, has been used as a marker, as it binds to the Mn 4 CaO 5 cluster in the S 2 and S 3 states. Since the ammonia-bound OEC is active, the ammonia-binding Mn site is not a substrate water site. This approach, together with a comparison of the native dark and 2F states, is used to discriminate between proposed O-O bond formation mechanisms.

  20. One-dimensional Co(II)/Ni(II) complexes of 2-hydroxyisophthalate: Structures and magnetic properties

    International Nuclear Information System (INIS)

    Wang, Kai; Zou, Hua-Hong; Chen, Zi-Lu; Zhang, Zhong; Sun, Wei-Yin; Liang, Fu-Pei

    2015-01-01

    The solvothermal reactions of 2-hydroxyisophthalic acid (H 3 ipO) with M(NO 3 ) 2 ∙6H 2 O (M=Co, Ni) afforded two complexes [Co 2 (HipO) 2 (Py) 2 (H 2 O) 2 ] (1) and [Ni(HipO)(Py)H 2 O] (2) (Py=pyridine). They exhibit similar zig-zag chain structures with the adjacent two metal centers connected by a anti-syn bridging carboxylate group from the HipO 2− ligand. The magnetic measurements reveal the dominant antiferromagnetic interactions and spin-canting in 1 while ferromagnetic interactions in 2. Both of them exhibit magnetocaloric effect (MCE) with the resulting entropy changes (−ΔS m ) of 12.51 J kg −1 K −1 when ΔH=50 kOe at 3 K for 1 and 11.01 J kg −1 K −1 when ΔH=50 kOe at 3 K for 2, representing the rare examples of one-dimensional complexes with MCE. - Graphical abstract: Synopsis: Two Co(II)/Ni(II) complexes with zig-zag chain structures have been reported. 1-Co shows cant-antiferromagnetism while 2-Ni shows ferromagnetism. Magnetocaloric effect is also found in both of them. - Highlights: • Two one-dimensional Co(II)/Ni(II) complexes were solvothermally synthesized. • The Co-complex exhibits canted antiferromagnetism. • The Ni-complex exhibits ferromagnetism. • Both of the complexes display magnetocaloric effect

  1. Wavelengths, energy levels and hyperfine structure of Mn II and Sc II.

    Science.gov (United States)

    Nave, Gillian; Pickering, Juliet C.; Townley-Smith, Keeley I. M.; Hala, .

    2015-08-01

    For many decades, the Atomic Spectroscopy Groups at the National Institute of Standards and Technology (NIST) and Imperial College London (ICL) have measured atomic data of astronomical interest. Our spectrometers include Fourier transform (FT) spectrometers at NIST and ICL covering the region 1350 Å to 5.5 μm and a 10.7-m grating spectrometer at NIST covering wavelengths from 300 - 5000 Å. Sources for these spectra include high-current continuous and pulsed hollow cathode (HCL) lamps, Penning discharges, and sliding spark discharges. Recent work has focused on the measurement and analysis of wavelengths, energy levels, and hyperfine structure (HFS) constants for iron-group elements. The analysis of FT spectra of Cr I, Mn I, and Mn II is being led by ICL and is described in a companion poster [1]. Current work being led by NIST includes the analysis of HFS in Mn II, analysis of Mn II in the vacuum ultraviolet, and a comprehensive analysis of Sc II.Comprehensive HFS constants for Mn II are needed for the interpretation of stellar spectra and incorrect abundances may be obtained when HFS is omitted. Holt et al. [2] have measured HFS constants for 59 levels of Mn II using laser spectroscopy. We used FT spectra of Mn/Ni and Mn/Cu HCLs covering wavelength ranges from 1350 Å to 5.4 μm to confirm 26 of the A constants of Holt et al. and obtain values for roughly 40 additional levels. We aim to obtain HFS constants for the majority of lines showing significant HFS that are observed in chemically-peculiar stars.Spectra of Sc HCLs have been recorded from 1800 - 6700 Å using a vacuum ultraviolet FT spectrometer at NIST. Additional measurements to cover wavelengths above 6700 Å and below 1800 Å are in progress. The spectra are being analyzed by NIST and Alighar Muslim University, India in order to derive improved wavelengths, energy levels, and hyperfine structure parameters.This work was partially supported by NASA, the STFC and PPARC (UK), the Royal Society of the UK

  2. DNA structure in human RNA polymerase II promoters

    DEFF Research Database (Denmark)

    Pedersen, Anders Gorm; Baldi, Pierre; Chauvin, Yves

    1998-01-01

    with a very low level of sequence similarity. The sequences, which include both TATA-containing and TATA-less promoters, are aligned by hidden Markov models. Using three different models of sequence-derived DNA bendability, the aligned promoters display a common structural profile with bendability being low...... protein in a manner reminiscent of DNA in a nucleosome. This notion is further supported by the finding that the periodic bendability is caused mainly by the complementary triplet pairs CAG/CTG and GGC/GCC, which previously have been found to correlate with nucleosome positioning. We present models where......The fact that DNA three-dimensional structure is important for transcriptional regulation begs the question of whether eukaryotic promoters contain general structural features independently of what genes they control. We present an analysis of a large set of human RNA polymerase II promoters...

  3. Waste disposal of HYLIFE II structure: Issues and assessment

    International Nuclear Information System (INIS)

    Lee, J.D.

    1992-01-01

    Initial analysis has shown that by using 304 stainless steel (SS) a significant fraction (92 wt%) of the structural mass in the initial HYLIFE-II design could be disposed of by shallow burial. And if all the structural components are mixed together and treated as one entity, all of it could be disposed of by shallow burial. Two other types of SSs assessed, Mn-modified 316 and Prime Candidate Alloy (PCA), were found to require disposal by deep geologic burial of most of the structural mass. The presents of Nb and Mo in Mn-modified 316 and Prime Candidate Alloy (PCA), were found to dominate the generation of long term wastes produced and their presence should be avoided

  4. Delexical Structures Contrastively: A Common Trap for Non-Native Speakers

    Directory of Open Access Journals (Sweden)

    Marjeta Vrbinc

    2004-12-01

    Full Text Available This article deals with delexical structures and in particular with the problems non-native speakers are faced with when encoding. First, it gives reasons why it is necessary to study the structures and then it discusses the delexical structures in English (monolingual context. The second part of the article focuses on the bilingual aspect, i.e. the translation of English delexical structures into Slovene. Some problems concerning the bilingual context are presented, especially as regards aspect and the difference between the translation of English delexical structures in isolation (e.g. in a dictionary and within the context. The last part of the article concentrates on the dictionary treatment of delexical structures and provides some examples taken from the latest editions of the leading EFL monolingual dictionaries.

  5. Spiral chain structure of high pressure selenium-II' and sulfur-II from powder x-ray diffraction

    International Nuclear Information System (INIS)

    Fujihisa, Hiroshi; Yamawaki, Hiroshi; Sakashita, Mami; Yamada, Takahiro; Honda, Kazumasa; Akahama, Yuichi; Kawamura, Haruki; Le Bihan, Tristan

    2004-01-01

    The structure of high pressure phases, selenium-II ' (Se-II ' ) and sulfur-II (S-II), for α-Se 8 (monoclinic Se-I) and α-S 8 (orthorhombic S-I) was studied by powder x-ray diffraction experiments. Se-II ' and S-II were found to be isostructural and to belong to the tetragonal space group I4 1 /acd, which is made up of 16 atoms in the unit cell. The structure consisted of unique spiral chains with both 4 1 and 4 3 screws. The results confirmed that the structure sequence of the pressure-induced phase transitions for the group VIb elements depended on the initial molecular form. The chemical bonds of the phases are also discussed from the interatomic distances that were obtained

  6. Protonated ions as systemic trapping agents for noble gases: From electronic structure to radiative association.

    Science.gov (United States)

    Ozgurel, O; Pauzat, F; Pilmé, J; Ellinger, Y; Bacchus-Montabonel, M-C; Mousis, O

    2017-10-07

    The deficiencies of argon, krypton, and xenon observed in the atmosphere of Titan as well as anticipated in some comets might be related to a scenario of sequestration by H 3 + in the gas phase at the early evolution of the solar nebula. The chemical process implied is a radiative association, evaluated as rather efficient in the case of H 3 + , especially for krypton and xenon. This mechanism of chemical trapping might not be limited to H 3 + only, considering that the protonated ions produced in the destruction of H 3 + by its main competitors present in the primitive nebula, i.e., H 2 O, CO, and N 2 , might also give stable complexes with the noble gases. However the effective efficiency of such processes is still to be proven. Here, the reactivity of the noble gases Ar, Kr, and Xe, with all protonated ions issued from H 2 O, CO, and N 2 , expected to be present in the nebula with reasonably high abundances, has been studied with quantum simulation method dynamics included. All of them give stable complexes and the rate coefficients of their radiative associations range from 10 -16 to 10 -19 cm 3 s -1 , which is reasonable for such reactions and has to be compared to the rates of 10 -16 to 10 -18 cm 3 s -1 , obtained with H 3 + . We can consider this process as universal for all protonated ions which, if present in the primitive nebula as astrophysical models predict, should act as sequestration agents for all three noble gases with increasing efficiency from Ar to Xe.

  7. Crystal structure of a trapped phosphate intermediate in vanadium apochloroperoxidase catalyzing a dephosphorylation reaction

    NARCIS (Netherlands)

    de Macedo-Ribeiro, S.; Renirie, R.; Wever, R.; Messerschmidt, A.

    2008-01-01

    The crystal structure of the apo form of vanadium chloroperoxidase from Curvularia inaequalis reacted with para-nitrophenylphosphate was determined at a resolution of 1.5 Å. The aim of this study was to solve structural details of the dephosphorylation reaction catalyzed by this enzyme. Since the

  8. Globalisation Trapped

    Directory of Open Access Journals (Sweden)

    João Caraça

    2017-05-01

    Full Text Available The promise of making society progress through the direct applications of science was finally fulfilled in the mid-20th century. Science progressed immensely, propelled by the effects of the two world wars. The first science-based technologies saw the daylight during the 1940s and their transformative power was such that neither the military, nor subsequently the markets, allowed science to return intact to its curiosity-driven nest. Technoscience was born then and (being progressively pulled away from curiosity-driven science was able to grow enormously, erecting a formidable structure of networks of institutions that impacted decisively on the economy. It is a paradox, or maybe a trap, that the fulfillment of science’s solemn promise of ‘transforming nature’ means seeing ourselves and our Western societies entangled in crises after crises with no clear outcome in view. A redistribution of geopolitical power is under way, along with the deployment of information and communication technologies, forcing dominant structures to oscillate, as knowledge about organization and methods, marketing, design, and software begins to challenge the role of technoscience as the main vector of economic growth and wealth accumulation. What ought to be done?

  9. Sequestration of chelated copper by structural Fe(II): Reductive decomplexation and transformation of Cu{sup II}-EDTA

    Energy Technology Data Exchange (ETDEWEB)

    He, Hongping [State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science & Engineering, Tongji University, Shanghai 200092 (China); Wu, Deli, E-mail: wudeli@tongji.edu.cn [State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science & Engineering, Tongji University, Shanghai 200092 (China); Zhao, Linghui [State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science & Engineering, Tongji University, Shanghai 200092 (China); Luo, Cong [School of Civil and Environmental Engineering, Georgia Institute of Technology, GA 30332 (United States); Dai, Chaomeng; Zhang, Yalei [State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science & Engineering, Tongji University, Shanghai 200092 (China)

    2016-05-15

    Highlights: • Structural Fe(II) was found to reveal high sequestration potential in various chelated copper. • Chelated copper was reduced to Cu(0) and Cu{sub 2}O by =Fe(II), whcih was oxidized to Fe{sub 2}O{sub 3}·H{sub 2}O. • Both electron transfer and surface =Fe(II) were found to be crucial during chelated copper reduction. • The indispensible role of reductive decomplexation was identified in chelated copper sequestration. - Abstract: Chelated coppers, such as Cu{sup II}-EDTA, are characteristically refractory and difficult to break down because of their high stability and solubility. Cu{sup II}–EDTA sequestration by structural Fe(II) (=Fe(II)) was investigated intensively in this study. Up to 101.21 mgCu(II)/gFe(II) was obtained by =Fe(II) in chelated copper sequestration under near neutral pH condition (pH 7.70). The mechanism of Cu{sup II}-EDTA sequestration by =Fe(II) was concluded as follows: 3Cu{sup II}–EDTA + 7=Fe(II) + 9H{sub 2}O → Cu(0) ↓ + Cu{sub 2}O ↓ (the major product) + 2Fe{sub 2}O{sub 3}·H{sub 2}O ↓ + 3Fe{sup II}–EDTA +14H{sup +} Novel results strongly indicate that Cu{sup II} reductive transformation induced by surface =Fe(II) was mainly responsible for chelated copper sequestration. Cu(0) generation was initially facilitated, and subsequent reduction of Cu(II) into Cu(I) was closely combined with the gradual increase of ORP (Oxidation-Reduction Potential). Cu-containing products were inherently stable, but Cu{sub 2}O would be reoxidized to Cu(II) with extra-aeration, resulting in the release of copper, which was beneficial to Cu reclamation. Concentration diminution of Cu{sup II}–EDTA within the electric double layer and competitive adsorption were responsible for the negative effects of Ca{sup 2+}, Mg{sup 2+}. By generating vivianite, PO{sub 4}{sup 3−} was found to decrease surface =Fe(II) content. This study is among the first ones to identify the indispensible role of reductive decomplexation in chelated copper

  10. Engineering characterization of ground motion. Task II: Soil structure interaction effects on structural response

    Energy Technology Data Exchange (ETDEWEB)

    Luco, J E; Wong, H L [Structural and Earthquake Engineering Consultants, Inc., Sierra Madre, CA (United States); Chang, C -Y; Power, M S; Idriss, I M [Woodward-Clyde Consultants, Walnut Creek, CA (United States)

    1986-08-01

    This report presents the results of part of a two-task study on the engineering characterization of earthquake ground motion for nuclear power plant design. The overall objective of this research program sponsored by the U.S. Nuclear Regulatory Commission (USNRC) is to develop recommendations for methods for selecting design response spectra or acceleration time histories to be used to characterize motion at the foundation level of nuclear power plants. Task I of the study, which is presented in Vol. 1 of NUREG/CR-3805, developed a basis for selecting design response spectra taking into account the characteristics of free-field ground motion found to be significant in causing structural damage. Task II incorporates additional considerations of effects of spatial variations of ground motions and soil-structure interaction on foundation motions and structural response. The results of Task II are presented in Vols. 2 through of NUREG/CR-3805 as follows: Vol. 2 effects of ground motion characteristics on structural response considering localized structural nonlinearities and soil-structure interaction effects; Vol. 3 observational data on spatial variations of earthquake ground motions; Vol. 4 soil-structure interaction effects on structural response; and Vol. 5, summary based on Tasks I and II studies. This report presents the results of the Vol. 4 studies.

  11. FASTRAN II - FATIGUE CRACK GROWTH STRUCTURAL ANALYSIS (UNIX VERSION)

    Science.gov (United States)

    Newman, J. C.

    1994-01-01

    Predictions of fatigue crack growth behavior can be made with the Fatigue Crack Growth Structural Analysis (FASTRAN II) computer program. As cyclic loads are applied to a selected crack configuration with an initial crack size, FASTRAN II predicts crack growth as a function of cyclic load history until either a desired crack size is reached or failure occurs. FASTRAN II is based on plasticity-induced crack-closure behavior of cracks in metallic materials and accounts for load-interaction effects, such as retardation and acceleration, under variable-amplitude loading. The closure model is based on the Dugdale model with modifications to allow plastically deformed material to be left along the crack surfaces as the crack grows. Plane stress and plane strain conditions, as well as conditions between these two, can be simulated in FASTRAN II by using a constraint factor on tensile yielding at the crack front to approximately account for three-dimensional stress states. FASTRAN II contains seventeen predefined crack configurations (standard laboratory fatigue crack growth rate specimens and many common crack configurations found in structures); and the user can define one additional crack configuration. The baseline crack growth rate properties (effective stress-intensity factor against crack growth rate) may be given in either equation or tabular form. For three-dimensional crack configurations, such as surface cracks or corner cracks at holes or notches, the fatigue crack growth rate properties may be different in the crack depth and crack length directions. Final failure of the cracked structure can be modelled with fracture toughness properties using either linear-elastic fracture mechanics (brittle materials), a two-parameter fracture criterion (brittle to ductile materials), or plastic collapse (extremely ductile materials). The crack configurations in FASTRAN II can be subjected to either constant-amplitude, variable-amplitude or spectrum loading. The applied

  12. FASTRAN II - FATIGUE CRACK GROWTH STRUCTURAL ANALYSIS (IBM PC VERSION)

    Science.gov (United States)

    Newman, J. C.

    1994-01-01

    Predictions of fatigue crack growth behavior can be made with the Fatigue Crack Growth Structural Analysis (FASTRAN II) computer program. As cyclic loads are applied to a selected crack configuration with an initial crack size, FASTRAN II predicts crack growth as a function of cyclic load history until either a desired crack size is reached or failure occurs. FASTRAN II is based on plasticity-induced crack-closure behavior of cracks in metallic materials and accounts for load-interaction effects, such as retardation and acceleration, under variable-amplitude loading. The closure model is based on the Dugdale model with modifications to allow plastically deformed material to be left along the crack surfaces as the crack grows. Plane stress and plane strain conditions, as well as conditions between these two, can be simulated in FASTRAN II by using a constraint factor on tensile yielding at the crack front to approximately account for three-dimensional stress states. FASTRAN II contains seventeen predefined crack configurations (standard laboratory fatigue crack growth rate specimens and many common crack configurations found in structures); and the user can define one additional crack configuration. The baseline crack growth rate properties (effective stress-intensity factor against crack growth rate) may be given in either equation or tabular form. For three-dimensional crack configurations, such as surface cracks or corner cracks at holes or notches, the fatigue crack growth rate properties may be different in the crack depth and crack length directions. Final failure of the cracked structure can be modelled with fracture toughness properties using either linear-elastic fracture mechanics (brittle materials), a two-parameter fracture criterion (brittle to ductile materials), or plastic collapse (extremely ductile materials). The crack configurations in FASTRAN II can be subjected to either constant-amplitude, variable-amplitude or spectrum loading. The applied

  13. Evolution of the local structure of ferric gels and polymers during the crystallisation of iron oxides. Application to uranium trapping

    International Nuclear Information System (INIS)

    Combes, Jean-Marie

    1988-01-01

    A first part of this research thesis reports the study of the structure of the main iron oxides and oxy-hydroxides, and of the protocols for the synthesis of ferric gels. The second part reports a topological approach by EXAFS (Extended X-Ray Absorption Fine Structure) of the structure of Mn and Fe oxides and oxy-hydroxides. The third part reports the study of the formation of ferric oxides from aqueous solutions by using a polyhedral approach by X-ray absorption spectroscopy in the case of hydrolysis and formation of ferric gels, and in the case of haematite formation from ferric gels. The next parts respectively report the study of the local structure of gels synthesised from iron(II), and the study of the local structure of natural ferric gels. Then, the author reports the study of sites of uranium bonding on ferric gels [fr

  14. Evaluation of Turner relaxed state as a model of long-lived ion-trapping structures in plasma focus and Z-pinches

    Science.gov (United States)

    Auluck, S. K. H.

    2011-03-01

    Relatively long-lived spheroidal structures coincident with the neutron emission phase have been observed in frozen deuterium fiber Z-pinch and some plasma focus devices. Existence of energetic ion-trapping mechanism in plasma focus has also been inferred from experimental data. It has been conjectured that these are related phenomena. This paper applies Turner's theory [L. Turner, IEEE Trans. Plasma Sci. 14, 849 (1986)] of relaxation of a Hall magnetofluid to construct a model of these structures and ion-trapping mechanism. Turner's solution modified for a finite-length plasma is used to obtain expressions for the magnetic field, velocity, and equilibrium pressure fields and is shown to represent an entity which is simultaneously a fluid vortex, a force-free magnetic field, a confined finite-pressure plasma, a charged object, and a trapped energetic ion beam. Characteristic features expected from diagnostic experiments are evaluated and shown to resemble experimental observations.

  15. [Fungal community structure in phase II composting of Volvariella volvacea].

    Science.gov (United States)

    Chen, Changqing; Li, Tong; Jiang, Yun; Li, Yu

    2014-12-04

    To understand the fungal community succession during the phase II of Volvariella volvacea compost and clarify the predominant fungi in different fermentation stages, to monitor the dynamic compost at the molecular level accurately and quickly, and reveal the mechanism. The 18S rDNA-denaturing gradient gel electrophoresis (DGGE) and sequencing methods were used to analyze the fungal community structure during the course of compost. The DGGE profile shows that there were differences in the diversity of fungal community with the fermentation progress. The diversity was higher in the stages of high temperature. And the dynamic changes of predominant community and relative intensity was observed. Among the 20 predominant clone strains, 9 were unknown eukaryote and fungi, the others were Eurotiales, Aspergillus sp., Melanocarpus albomyces, Colletotrichum sp., Rhizomucor sp., Verticillium sp., Penicillium commune, Microascus trigonosporus and Trichosporon lactis. The 14 clone strains were detected in the stages of high and durative temperature. The fungal community structure and predominant community have taken dynamic succession during the phase II of Volvariella volvacea compost.

  16. Nanoelectrospray high capacity ion trap multiple stage mass spectrometry for the structural analysis of human brain gangliosides

    International Nuclear Information System (INIS)

    Vukelic, Zeljka; Ratiu, Cornelia; Grozescu, Ioan; Zamfir, Alina Diana

    2006-01-01

    Full text: A novel protocol based on electrospray ionization (ESI) multiple stage high capacity ion trap (HCT) mass spectrometry (MS) was developed for glycosphingolipidomic surveys. The method was optimized for detailed structural elucidation of human brain gangliosides and particularly applied to human hippocampus-associated structures. The multiple stage MS experiments allowed for a complete structural characterization of GM1 ganglioside species, which was achieved by elucidation of the oligosaccharide sequence, identification of the GM1 a structural isomer from the data upon sialic acid localization along the sugar backbone and determination of the d18:1/18:0 of fatty acid/sphingoid base composition of the ceramide moiety. The methodology developed here is of general practical applicability for glycolipids and represents a step forward in the implementation of the advanced and most modern MS methods in glycomics. Gangliosides are glycosphingolipids, which consist of a mono- to polysialylated oligosaccharide chain of variable length attached to a ceramide portion of different composition with respect to the type of sphingoid base and fatty acid residues. Among all body systems, the central nervous system (CNS) possesses the highest content of gangliosides and they are playing a particularly important biological role at this level. Specific changes in the ganglioside expression and type of the expressed structures were observed to occur during brain development, maturation, and aging, and due to diseases or neurodegeneration processes. Gangliosides represent, therefore, an important class of biomarkers, carriers of information upon various CNS processes and events. Though in the human brain, their expression was observed to have a regional and tissue development induced specificity, the differences in ganglioside structure, composition and quantity were not systematically investigated or rigorously determined so far. (authors)

  17. Microfabricated Waveguide Atom Traps.

    Energy Technology Data Exchange (ETDEWEB)

    Jau, Yuan-Yu [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-09-01

    A nanoscale , microfabricated waveguide structure can in - principle be used to trap atoms in well - defined locations and enable strong photon-atom interactions . A neutral - atom platform based on this microfabrication technology will be prealigned , which is especially important for quantum - control applications. At present, there is still no reported demonstration of evanescent - field atom trapping using a microfabricated waveguide structure. We described the capabilities established by our team for future development of the waveguide atom - trapping technology at SNL and report our studies to overcome the technical challenges of loading cold atoms into the waveguide atom traps, efficient and broadband optical coupling to a waveguide, and the waveguide material for high - power optical transmission. From the atomic - physics and the waveguide modeling, w e have shown that a square nano-waveguide can be utilized t o achieve better atomic spin squeezing than using a nanofiber for first time.

  18. Nematode-Trapping Fungi.

    Science.gov (United States)

    Jiang, Xiangzhi; Xiang, Meichun; Liu, Xingzhong

    2017-01-01

    Nematode-trapping fungi are a unique and intriguing group of carnivorous microorganisms that can trap and digest nematodes by means of specialized trapping structures. They can develop diverse trapping devices, such as adhesive hyphae, adhesive knobs, adhesive networks, constricting rings, and nonconstricting rings. Nematode-trapping fungi have been found in all regions of the world, from the tropics to Antarctica, from terrestrial to aquatic ecosystems. They play an important ecological role in regulating nematode dynamics in soil. Molecular phylogenetic studies have shown that the majority of nematode-trapping fungi belong to a monophyletic group in the order Orbiliales (Ascomycota). Nematode-trapping fungi serve as an excellent model system for understanding fungal evolution and interaction between fungi and nematodes. With the development of molecular techniques and genome sequencing, their evolutionary origins and divergence, and the mechanisms underlying fungus-nematode interactions have been well studied. In recent decades, an increasing concern about the environmental hazards of using chemical nematicides has led to the application of these biological control agents as a rapidly developing component of crop protection.

  19. Structural analysis of group II chitinase (ChtII) catalysis completes the puzzle of chitin hydrolysis in insects.

    Science.gov (United States)

    Chen, Wei; Qu, Mingbo; Zhou, Yong; Yang, Qing

    2018-02-23

    Chitin is a linear homopolymer of N -acetyl-β-d-glucosamines and a major structural component of insect cuticles. Chitin hydrolysis involves glycoside hydrolase family 18 (GH18) chitinases. In insects, chitin hydrolysis is essential for periodic shedding of the old cuticle ecdysis and proceeds via a pathway different from that in the well studied bacterial chitinolytic system. Group II chitinase (ChtII) is a widespread chitinolytic enzyme in insects and contains the greatest number of catalytic domains and chitin-binding domains among chitinases. In Lepidopterans, ChtII and two other chitinases, ChtI and Chi-h, are essential for chitin hydrolysis. Although ChtI and Chi-h have been well studied, the role of ChtII remains elusive. Here, we investigated the structure and enzymology of Of ChtII, a ChtII derived from the insect pest Ostrinia furnacalis We present the crystal structures of two catalytically active domains of Of ChtII, Of ChtII-C1 and Of ChtII-C2, both in unliganded form and complexed with chitooligosaccharide substrates. We found that Of ChtII-C1 and Of ChtII-C2 both possess long, deep substrate-binding clefts with endochitinase activities. Of ChtII exhibited structural characteristics within the substrate-binding cleft similar to those in Of Chi-h and Of ChtI. However, Of ChtII lacked structural elements favoring substrate binding beyond the active sites, including an extra wall structure present in Of Chi-h. Nevertheless, the numerous domains in Of ChtII may compensate for this difference; a truncation containing one catalytic domain and three chitin-binding modules ( Of ChtII-B4C1) displayed activity toward insoluble polymeric substrates that was higher than those of Of Chi-h and Of ChtI. Our observations provide the last piece of the puzzle of chitin hydrolysis in insects. © 2018 by The American Society for Biochemistry and Molecular Biology, Inc.

  20. Synthesis and structural characterisation of iron(II) and copper(II) diphosphates containing flattened metal oxotetrahedra

    International Nuclear Information System (INIS)

    Keates, Adam C.; Wang, Qianlong; Weller, Mark T.

    2014-01-01

    Single crystal and bulk polycrystalline forms of K 2 MP 2 O 7 (M=Fe(II), Cu(II)) have been synthesised and their structures determined from single crystal X-ray diffraction data. Both compounds crystallize in the tetragonal system, space group P-42 1 m. Their structures are formed from infinite sheets of linked oxopolyhedra of the stoichiometry [MP 2 O 7 ] 2− with potassium cations situated between the layers. The MO 4 tetrahedra share oxygen atoms with [P 2 O 7 ] 4− diphosphate groups and the potassium ions have KO 8 square prismatic geometry. In both compounds the M(II) centre has an unusual strongly flattened, tetrahedral coordination to oxygen, as a result of the Jahn–Teller (JT) effect for the high spin d 6 Fe(II) and p-orbital mixing or a second order JT effect for d 9 Cu(II) centres in four fold coordination. The uncommon transition metal ion environments found in these materials are reflected in their optical absorption spectra and magnetism data. - Graphical abstract: The structures of the tetragonal polymorphs of K 2 MP 2 O 7 , M=Cu(II), Fe(II), consist of infinite sheets of stoichiometry [MP 2 O 7 ] 2− , formed from linked pyrophosphate groups and MO 4 tetrahedra, separated by potassium ions. In both compounds the unusual tetrahedral coordination of the M(II) centre is strongly flattened as a result of Jahn–Teller (JT) effects for high spin, d 6 Fe(II) and p-orbital mixing and second-order JT effects for d 9 Cu(II). Display Omitted - Highlights: • Tetrahedral copper and iron(II) coordinated by oxygen. • New layered phosphate structure. • Jahn–Teller and d 10 distorted coordinations

  1. Crystal structure of a trapped catalytic intermediate suggests that forced atomic proximity drives the catalysis of mIPS.

    Science.gov (United States)

    Neelon, Kelly; Roberts, Mary F; Stec, Boguslaw

    2011-12-07

    1-L-myo-inositol-phosphate synthase (mIPS) catalyzes the first step of the unique, de novo pathway of inositol biosynthesis. However, details about the complex mIPS catalytic mechanism, which requires oxidation, enolization, intramolecular aldol cyclization, and reduction, are not fully known. To gain further insight into this mechanism, we determined the crystal structure of the wild-type mIPS from Archaeoglobus fulgidus at 1.7 Å, as well as the crystal structures of three active-site mutants. Additionally, we obtained the structure of mIPS with a trapped 5-keto-glucose-6-phosphate intermediate at 2 Å resolution by a novel (to our knowledge) process of activating the crystal at high temperature. A comparison of all of the crystal structures of mIPS described in this work suggests a novel type of catalytic mechanism that relies on the forced atomic proximity of functional groups. The lysine cluster is contained in a small volume in the active site, where random motions of these side chains are responsible for the progress of the complex multistep reaction as well as for the low rate of catalysis. The mechanism requires that functional groups of Lys-274, Lys-278, Lys-306, and Lys-367 assume differential roles in the protonation/deprotonation steps that must occur during the mIPS reaction. This mechanism is supported by the complete loss of activity of the enzyme caused by the Leu-257 mutation to Ala that releases the lysine containment. Copyright © 2011 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  2. Tin( ii ) ketoacidoximates: synthesis, X-ray structures and processing to tin( ii ) oxide

    KAUST Repository

    Khanderi, Jayaprakash

    2015-10-21

    Tin(ii) ketoacidoximates of the type [HONCRCOO]Sn (R = Me 1, CHPh 2) and (MeONCMeCOO)Sn] NH·2HO 3 were synthesized by reacting pyruvate- and hydroxyl- or methoxylamine RONH (R = H, Me) with tin(ii) chloride dihydrate SnCl·2HO. The single crystal X-ray structure reveals that the geometry at the Sn atom is trigonal bipyramidal in 1, 2 and trigonal pyramidal in 3. Inter- or intramolecular hydrogen bonding is observed in 1-3. Thermogravimetric (TG) analysis shows that the decomposition of 1-3 to SnO occurs at ca. 160 °C. The evolved gas analysis during TG indicates complete loss of the oximato ligand in one step for 1 whereas a small organic residue is additionally removed at temperatures >400 °C for 2. Above 140 °C, [HONC(Me)COO]Sn (1) decomposes in air to spherical SnO particles of size 10-500 nm. Spin coating of 1 on Si or a glass substrate followed by heating at 200 °C results in a uniform film of SnO. The band gap of the produced SnO film and nanomaterial was determined by diffuse reflectance spectroscopy to be in the range of 3.0-3.3 eV. X-ray photoelectron spectroscopy indicates surface oxidation of the SnO film to SnO in ambient atmosphere.

  3. Structural Changes in Isometrically Contracting Insect Flight Muscle Trapped following a Mechanical Perturbation

    Science.gov (United States)

    Wu, Shenping; Liu, Jun; Perz-Edwards, Robert J.; Tregear, Richard T.; Winkler, Hanspeter; Franzini-Armstrong, Clara; Sasaki, Hiroyuki; Goldman, Yale E.; Reedy, Michael K.; Taylor, Kenneth A.

    2012-01-01

    The application of rapidly applied length steps to actively contracting muscle is a classic method for synchronizing the response of myosin cross-bridges so that the average response of the ensemble can be measured. Alternatively, electron tomography (ET) is a technique that can report the structure of the individual members of the ensemble. We probed the structure of active myosin motors (cross-bridges) by applying 0.5% changes in length (either a stretch or a release) within 2 ms to isometrically contracting insect flight muscle (IFM) fibers followed after 5–6 ms by rapid freezing against a liquid helium cooled copper mirror. ET of freeze-substituted fibers, embedded and thin-sectioned, provides 3-D cross-bridge images, sorted by multivariate data analysis into ∼40 classes, distinct in average structure, population size and lattice distribution. Individual actin subunits are resolved facilitating quasi-atomic modeling of each class average to determine its binding strength (weak or strong) to actin. ∼98% of strong-binding acto-myosin attachments present after a length perturbation are confined to “target zones” of only two actin subunits located exactly midway between successive troponin complexes along each long-pitch helical repeat of actin. Significant changes in the types, distribution and structure of actin-myosin attachments occurred in a manner consistent with the mechanical transients. Most dramatic is near disappearance, after either length perturbation, of a class of weak-binding cross-bridges, attached within the target zone, that are highly likely to be precursors of strong-binding cross-bridges. These weak-binding cross-bridges were originally observed in isometrically contracting IFM. Their disappearance following a quick stretch or release can be explained by a recent kinetic model for muscle contraction, as behaviour consistent with their identification as precursors of strong-binding cross-bridges. The results provide a detailed model

  4. Crystal structure of dichloridobis(dimethyl N-cyanodithioiminocarbonatecobalt(II

    Directory of Open Access Journals (Sweden)

    Mouhamadou Birame Diop

    2016-01-01

    Full Text Available The structure of the mononuclear title complex, [{(H3CS2C=NC[triple-bond] N}2CoCl2], consists of a CoII atom coordinated in a distorted tetrahedral manner by two Cl− ligands and the terminal N atoms of two dimethyl N-cyanodithioiminocarbonate ligands. The two organic ligands are almost coplanar, with a dihedral angle of 5.99 (6° between their least-squares planes. The crystal packing features pairs of inversion-related complexes that are held together through C—H...Cl and C—H...S interactions and π–π stacking [centroid-to-centroid distance = 3.515 (su? Å]. Additional C—H...Cl and C—H...S interactions, as well as Cl...S contacts < 3.6 Å, consolidate the crystal packing.

  5. Hydrogen trapping by VC precipitates and structural defects in a high strength Fe–Mn–C steel studied by small-angle neutron scattering

    International Nuclear Information System (INIS)

    Malard, B.; Remy, B.; Scott, C.; Deschamps, A.; Chêne, J.; Dieudonné, T.; Mathon, M.H.

    2012-01-01

    Highlights: ► SANS was used to study the interaction between H and a Fe–Mn–C steel containing V. ► No interaction between H and V in solid solution has been detected. ► A reversible interaction between H and structural defects has been measured. ► 5 ppm wt. of H can be trapped in the VC nanoprecipitates. - Abstract: The trapping of hydrogen by VC precipitates and structural defects in high strength Fe–Mn–C steel was studied by small angle neutron scattering. No interaction between H and V in solid solution has been detected but a significant interaction between H and structural defects introduced by plastic deformation has been measured. This last effect was reversible upon outgassing of the H. Moreover a significant interaction between H and VC precipitates has been measured; 5 ppm wt. of H could be trapped in the precipitates. This is consistent with the homogeneous trapping of H within the precipitates rather than at the precipitate/matrix interface.

  6. The origin of traps and the effect of nitrogen plasma in oxide-nitride-oxide structures for non-volatile memories

    International Nuclear Information System (INIS)

    Kim, W. S.; Kwak, D. W.; Oh, J. S.; Lee, D. W.; Cho, H. Y.

    2010-01-01

    Ultrathin oxide-nitride-oxide (ONO) dielectric stacked layers are fundamental structures of silicon-oxide-nitride-oxide-silicon (SONOS) non-volatile memory devices in which information is known to be stored as charges trapped in silicon nitride. Deep-level transient spectroscopy (DLTS) and a capacitance-voltage (CV) analysis were introduced to observe the trap behavior related to the memory effect in memory devices. The DLTS results verified that the nitride-related traps were a dominant factor in the memory effect. The energy of hole traps was 0.307 eV above the balance band. To improve the memory effects of the non-volatile memory devices with ONO structures, we introduced a nitrogen plasma treatment. After the N-plasma treatment, the flat-band voltage shift (ΔV FB ) was increased by about 1.5 times. The program and the erase (P-E) characteristics were also shown to be better than those for the as-ONO structure. In addition, the retention characteristics were improved by over 2.4 times.

  7. Characteristics of trapped electrons and electron traps in single crystals

    International Nuclear Information System (INIS)

    Budzinski, E.E.; Potter, W.R.; Potienko, G.; Box, H.C.

    1979-01-01

    Two additional carbohydrates are reported whose crystal structures trap electrons intermolecularly in single crystals x irradiated at low temperature, namely sucrose and rhamnose. Five carbohydrate and polyhydroxy compounds are now known which exhibit this phenomenon. The following characteristics of the phenomenon were investigated: (1) the hyperfine couplings of the electron with protons of the polarized hydroxy groups forming the trap; (2) the distances between these protons and the trapped electron; (3) the spin density of the electron at the protons and (4) the relative stabilities of the electron trapped in various crystal structures

  8. Structural characterization and antioxidant properties of Cu(II) and Ni(II) complexes derived from dicyandiamide

    Science.gov (United States)

    Kertmen, Seda Nur; Gonul, Ilyas; Kose, Muhammet

    2018-01-01

    New Cu(II) and Ni(II) complexes derived from dicyandiamide were synthesized and characterised by spectroscopic and analytical methods. Molecular structures of the complexes were determined by single crystal X-ray diffraction studies. In the complexes, the Cu(II) or Ni(II) ions are four-coordinate with a slight distorted square planar geometry. The ligands (L-nPen and L-iPen) derived from dicyandiamide formed via nucleophilic addition of alcohol solvent molecule in the presence Cu(II) or Ni(II) ions. Complexes were stabilised by intricate array of hydrogen bonding interactions. Antioxidant activity of the complexes was evaluated by DPPH radical scavenging and CUPRAC methods. The complexes exhibit antioxidant activity, however, their activities were much lower than standard antioxidants (Vitamin C and trolox).

  9. Metal-ion exchange induced structural transformation as a way of forming novel Ni(II)− and Cu(II)−salicylaldimine structures

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Jing-Yun, E-mail: jyunwu@ncnu.edu.tw; Tsai, Chi-Jou; Chang, Ching-Yun; Wu, Yung-Yuan

    2017-02-15

    A Zn(II)−salicylaldimine complex [Zn(L{sup salpyca})(H{sub 2}O)]{sub n} (1, where H{sub 2}L{sup salpyca}=4-hydroxy-3-(((pyridin-2-yl)methylimino)methyl)benzoic acid), with a one-dimensional (1D) chain structure, has been successfully converted to a discrete Ni(II)−salicylaldimine complex [Ni(L{sup salpyca})(H{sub 2}O){sub 3}] (2) and an infinite Cu(II)−salicylaldimine complex ([Cu(L{sup salpyca})]·3H{sub 2}O){sub n} (3) through a metal-ion exchange induced structural transformation process. However, such processes do not worked by Mn(II) and Co(II) ions. Solid-state structure analyses reveal that complexes 1–3 form comparable coordinative or supramolecular zigzag chains running along the crystallographic [201] direction. In addition, replacing Zn(II) ion by Ni(II) and Cu(II) ions caused changes in coordination environment and sphere of metal centers, from a 5-coordinate intermediate geometry of square pyramidal and trigonal bipyramidal in 1 to a 6-coordinate octahedral geometry in 2, and to a 4-coordiante square planar geometry in 3. This study shows that metal-ion exchange serves as a very efficient way of forming new coordination complexes that may not be obtained through direct synthesis. - Graphical abstract: A Zn(II)−salicylaldimine zigzag chain has been successfully converted to a Ni(II)−salicylaldimine supramolecular zigzag chain and a Cu(II)−salicylaldimine coordinative zigzag chain through metal-ion exchange induced structural transformations, which is not achieved by Mn(II) and Co(II) ions.

  10. An experiment to trap astromaterials in space in order to find bacteriomorphic structures

    Science.gov (United States)

    Steklov, A. F.; Vidmachenko, A. P.

    2018-05-01

    At search for bacteriomorphic structures in meteorites - usually pseudomorphoses. They are formed by minerals that do not differ in composition from the composition of the meteorite itself. After hitting on Earth, and then in museum collections, in meteorites could developed microorganisms. In modern conditions, bacterial life exists on land, in the aquatic environment, deep beneath the ice in Antarctica and in the high layers of the atmosphere at temperatures from -10 to +120°C. At a temperature outside these limits, bacteria can go into a dormant state, being in a viable state for millions of years. Interest in the results of biological studies of astromaterials has grown in recent years. The main source of such biological information are meteorites, which belong to the class of carbonaceous chondrites. All the data on their age are in the range of 4.4-4.59 billion years. NASA planned to prepare a mission with the goal of capturing an asteroid for in-depth study. We propose to "catch" not a whole asteroid. We only need a small meteoroid, such as carbonaceous chondrite. In this regard, it is him - we should catch in outer space, carefully conserve and then deliver for careful research in terrestrial conditions with the help of modern equipment. Thus, interplanetary matter is a good material for wide variety of astrobiological studies.

  11. Structure and trapping of three-dimensional dust clouds in a capacitively coupled rf-discharge

    International Nuclear Information System (INIS)

    Arp, O.; Block, D.; Piel, A.

    2005-01-01

    In this survey the recently found 'Coulomb balls' are discussed, which show an unusual kind of crystalline order. These three-dimensional dust clouds consisting of hundreds or thousands of micrometer-sized dust particles have a spherical shape and exist in a wide range of plasma conditions. Coulomb balls are optically highly transparent and have macroscopic dimensions of several millimeters in diameter. The clouds allow for the observation of each single particle and thus the complete reconstruction of the crystal structure by means of video microscopy techniques. The particles are arranged in distinct nested shells in which they form patterns with mostly five and six neighbors. The confinement of Coulomb balls by dielectric walls involves electric forces, surface charges, ion drag forces, and thermophoretic levitation. The thermophoretic force field is measured with tracer particles and particle image velocimetry (PIV). The electric forces are derived from simulations with the two-dimensional SIGLO-2D code. It is shown the the sum of all confining forces results in a stable potential well that describes levitation and spherical confinement of the Coulomb ball

  12. Safe trapping of cesium into pollucite structure by hot-pressing method

    International Nuclear Information System (INIS)

    Omerašević, Mia; Matović, Ljiljana; Ružić, Jovana; Golubović, Željko; Jovanović, Uroš; Mentus, Slavko; Dondur, Vera

    2016-01-01

    A simple one-step method with direct thermal conversion at lower temperatures for preparing a stabile Cs-aluminsilicate phase, known as pollucite, is presented. Cs-exchanged form of Na, Ca-LTA type of zeolite (Cs-LTA) was pressureless sintered and hot pressed at certain temperatures in order to obtain pollucite. XRD and FTIR analysis were used to study structural changes of Cs-LTA before and after thermal treatments. Pressureless sintered sample recrystallized into pollucite phase after heat treatment at 1000 °C (3 h) (PLS1000) and hot pressed sample at 750 °C (3 h) using pressure of 35 MPa (HP750), indicating reduced temperature of 250°. SEM micrographs confirmed that HP750 has higher density than PLS1000 which leads to higher value of compressive strength. The HP750 showed better resistance to Cs leaching than the PLS1000. Base on these results one can conclude that hot pressing is the promising method for the permanent disposal of Cs radionuclides. - Highlights: • Na, Ca-LTA zeolite showed high affinity for Cs ions. • Pollucite phase was obtained using hot pressing at temperature as low as ​750 °C. • HP750 shows better mechanical and morphological properties than PLS1000. • HP750 has lower leaching rate of Cs ions than PLS1000.

  13. Trapped antihydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Butler, E., E-mail: eoin.butler@cern.ch [CERN, Physics Department (Switzerland); Andresen, G. B. [Aarhus University, Department of Physics and Astronomy (Denmark); Ashkezari, M. D. [Simon Fraser University, Department of Physics (Canada); Baquero-Ruiz, M. [University of California, Department of Physics (United States); Bertsche, W. [Swansea University, Department of Physics (United Kingdom); Bowe, P. D. [Aarhus University, Department of Physics and Astronomy (Denmark); Cesar, C. L. [Universidade Federal do Rio de Janeiro, Instituto de Fisica (Brazil); Chapman, S. [University of California, Department of Physics (United States); Charlton, M.; Deller, A.; Eriksson, S. [Swansea University, Department of Physics (United Kingdom); Fajans, J. [University of California, Department of Physics (United States); Friesen, T.; Fujiwara, M. C. [University of Calgary, Department of Physics and Astronomy (Canada); Gill, D. R. [TRIUMF (Canada); Gutierrez, A. [University of British Columbia, Department of Physics and Astronomy (Canada); Hangst, J. S. [Aarhus University, Department of Physics and Astronomy (Denmark); Hardy, W. N. [University of British Columbia, Department of Physics and Astronomy (Canada); Hayden, M. E. [Simon Fraser University, Department of Physics (Canada); Humphries, A. J. [Swansea University, Department of Physics (United Kingdom); Collaboration: ALPHA Collaboration; and others

    2012-12-15

    Precision spectroscopic comparison of hydrogen and antihydrogen holds the promise of a sensitive test of the Charge-Parity-Time theorem and matter-antimatter equivalence. The clearest path towards realising this goal is to hold a sample of antihydrogen in an atomic trap for interrogation by electromagnetic radiation. Achieving this poses a huge experimental challenge, as state-of-the-art magnetic-minimum atom traps have well depths of only {approx}1 T ({approx}0.5 K for ground state antihydrogen atoms). The atoms annihilate on contact with matter and must be 'born' inside the magnetic trap with low kinetic energies. At the ALPHA experiment, antihydrogen atoms are produced from antiprotons and positrons stored in the form of non-neutral plasmas, where the typical electrostatic potential energy per particle is on the order of electronvolts, more than 10{sup 4} times the maximum trappable kinetic energy. In November 2010, ALPHA published the observation of 38 antiproton annihilations due to antihydrogen atoms that had been trapped for at least 172 ms and then released-the first instance of a purely antimatter atomic system confined for any length of time (Andresen et al., Nature 468:673, 2010). We present a description of the main components of the ALPHA traps and detectors that were key to realising this result. We discuss how the antihydrogen atoms were identified and how they were discriminated from the background processes. Since the results published in Andresen et al. (Nature 468:673, 2010), refinements in the antihydrogen production technique have allowed many more antihydrogen atoms to be trapped, and held for much longer times. We have identified antihydrogen atoms that have been trapped for at least 1,000 s in the apparatus (Andresen et al., Nature Physics 7:558, 2011). This is more than sufficient time to interrogate the atoms spectroscopically, as well as to ensure that they have relaxed to their ground state.

  14. Crystal Structures of Nitroalkane Oxidase: Insights into the Reaction Mechanism of a Covalent Complex of the Flavoenzyme Trapped During Turnover

    Energy Technology Data Exchange (ETDEWEB)

    Nagpal,A.; Valley, M.; Fitzpatrick, P.; Orville, A.

    2006-01-01

    Nitroalkane oxidase (NAO) from Fusarium oxysporum catalyzes the oxidation of neutral nitroalkanes to the corresponding aldehydes or ketones with the production of H2O2 and nitrite. The flavoenzyme is a new member of the acyl-CoA dehydrogenase (ACAD) family, but it does not react with acyl-CoA substrates. We present the 2.2 Angstroms resolution crystal structure of NAO trapped during the turnover of nitroethane as a covalent N5-FAD adduct (ES*). The homotetrameric structure of ES* was solved by MAD phasing with 52 Se-Met sites in an orthorhombic space group. The electron density for the N5-(2-nitrobutyl)-1,5-dihydro-FAD covalent intermediate is clearly resolved. The structure of ES* was used to solve the crystal structure of oxidized NAO at 2.07 Angstroms resolution. The c axis for the trigonal space group of oxidized NAO is 485 Angstroms, and there are six subunits (11/2 holoenzymes) in the asymmetric unit. Four of the active sites contain spermine (EI), a weak competitive inhibitor, and two do not contain spermine (E{sup ox}). The active-site structures of E{sup ox}, EI, and ES* reveal a hydrophobic channel that extends from the exterior of the protein and terminates at Asp402 and the N5 position on the re face of the FAD. Thus, Asp402 is in the correct position to serve as the active-site base, where it is proposed to abstract the {alpha} proton from neutral nitroalkane substrates. The structures for NAO and various members of the ACAD family overlay with root-mean-square deviations between 1.7 and 3.1 Angstroms. The homologous region typically spans more than 325 residues and includes Glu376, which is the active-site base in the prototypical member of the ACAD family. However, NAO and the ACADs exhibit differences in hydrogen-bonding patterns between the respective active-site base, substrate molecules, and FAD. These likely differentiate NAO from the homologues and, consequently, are proposed to result in the unique reaction mechanism of NAO.

  15. Characterization of structure and function of ZS-9, a K+ selective ion trap.

    Directory of Open Access Journals (Sweden)

    Fiona Stavros

    Full Text Available Hyperkalemia, a condition in which serum potassium ions (K+ exceed 5.0 mmol/L, is a common electrolyte disorder associated with substantial morbidity. Current methods of managing hyperkalemia, including organic polymer resins such as sodium polystyrene sulfonate (SPS, are poorly tolerated and/or not effective. Sodium zirconium cyclosilicate (ZS-9 is under clinical development as an orally administered, non-absorbed, novel, inorganic microporous zirconium silicate compound that selectively removes excess K+ in vivo. The development, structure and ion exchange properties of ZS-9 and its hypothesized mechanism of action are described. Based on calculation of the interatomic distances between the atoms forming the ZS-9 micropores, the size of the pore opening was determined to be ∼ 3 Å (∼ diameter of unhydrated K+. Unlike nonspecific organic polymer resins like SPS, the ZS-9 K+ exchange capacity (KEC was unaffected by the presence of calcium (Ca2+ or magnesium ions (Mg2+ and showed>25-fold selectivity for K+ over either Ca2+ or Mg2+. Conversely, the selectivity of SPS for K+ was only 0.2-0.3 times its selectivity for Ca2+ or Mg2+in mixed ionic media. It is hypothesized that the high K+ specificity of ZS-9 is attributable to the chemical composition and diameter of the micropores, which possibly act in an analogous manner to the selectivity filter utilized by physiologic K+ channels. This hypothesized mechanism of action is supported by the multi-ion exchange studies. The effect of pH on the KEC of ZS-9 was tested in different media buffered to mimic different portions of the human gastrointestinal tract. Rapid K+ uptake was observed within 5 minutes - mainly in the simulated small intestinal and large intestinal fluids, an effect that was sustained for up to 1 hour. If approved, ZS-9 will represent a novel, first-in-class therapy for hyperkalemia with improved capacity, selectivity, and speed for entrapping K+ when compared to currently

  16. Magnetic traps with a sperical separatrix: Tornado traps

    International Nuclear Information System (INIS)

    Peregood, B.P.; Lehnert, B.

    1979-11-01

    A review is given on the features of magnetic traps with a spherical separatrix, with special emphesis on Tornado spiral coil configurations. The confinement and heating of static plasmas in Tornado traps is treated, including the topology of the magnetic field structure, the magneto-mechanical properties of the magnetic coil system, as well as the particle orbits and plasma behaviour in these traps. In additio, the mode of rotating plasma operation by crossed electric and magnetic fields is being described. The results of experiments on static and rotating plasmas are summarized, and conclusions are drawn about future possibilities of Tornado traps for the creation and containment of hot plasmas. (author)

  17. Magnetic traps with a spherical separatrix: Tornado traps

    International Nuclear Information System (INIS)

    Peregood, B.P.; Lehnert, B.

    1981-01-01

    A review is given on the features of magnetic traps with a spherical separatrix, with special emphasis on Tornado spiral coil configurations. The confinement and heating of static plasms in Tornado traps is treated, including the topology of the magnetic field structure, the magneto-mechanical properties of the magnetic coil system, as well as the particle orbits and plasma behaviour in these traps. In addition, the mode of rotating plasma operation by crossed electric and magnetic fields is described. The results of experiments on static and rotating plasmas are summarized, and conclusions are drawn about future possibilities of Tornado traps in the creation and containment of hot plasmas. (orig.)

  18. The Latent Symptom Structure of the Beck Depression Inventory-II in Outpatients with Major Depression

    Science.gov (United States)

    Quilty, Lena C.; Zhang, K. Anne; Bagby, R. Michael

    2010-01-01

    The Beck Depression Inventory-II (BDI-II) is a self-report instrument frequently used in clinical and research settings to assess depression severity. Although investigators have examined the factor structure of the BDI-II, a clear consensus on the best fitting model has not yet emerged, resulting in different recommendations regarding how to best…

  19. Impulsively Generated Wave Trains in Coronal Structures. II. Effects of Transverse Structuring on Sausage Waves in Pressurelesss Slabs

    Science.gov (United States)

    Li, Bo; Guo, Ming-Zhe; Yu, Hui; Chen, Shao-Xia

    2018-03-01

    Impulsively generated sausage wave trains in coronal structures are important for interpreting a substantial number of observations of quasi-periodic signals with quasi-periods of order seconds. We have previously shown that the Morlet spectra of these wave trains in coronal tubes depend crucially on the dispersive properties of trapped sausage waves, the existence of cutoff axial wavenumbers, and the monotonicity of the dependence of the axial group speed on the axial wavenumber in particular. This study examines the difference a slab geometry may introduce, for which purpose we conduct a comprehensive eigenmode analysis, both analytically and numerically, on trapped sausage modes in coronal slabs with a considerable number of density profiles. For the profile descriptions examined, coronal slabs can trap sausage waves with longer axial wavelengths, and the group speed approaches the internal Alfvén speed more rapidly at large wavenumbers in the cylindrical case. However, common to both geometries, cutoff wavenumbers exist only when the density profile falls sufficiently rapidly at distances far from coronal structures. Likewise, the monotonicity of the group speed curves depends critically on the profile steepness right at the structure axis. Furthermore, the Morlet spectra of the wave trains are shaped by the group speed curves for coronal slabs and tubes alike. Consequently, we conclude that these spectra have the potential for inferring the subresolution density structuring inside coronal structures, although their detection requires an instrumental cadence of better than ∼1 s.

  20. Synthesis and structural characterisation of iron(II) and copper(II) diphosphates containing flattened metal oxotetrahedra

    Energy Technology Data Exchange (ETDEWEB)

    Keates, Adam C. [School of Chemistry, University of Southampton, Southampton, Hampshire SO17 1B,. UK (United Kingdom); Wang, Qianlong [Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY (United Kingdom); Weller, Mark T., E-mail: m.t.weller@bath.ac.uk [Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY (United Kingdom)

    2014-02-15

    Single crystal and bulk polycrystalline forms of K{sub 2}MP{sub 2}O{sub 7} (M=Fe(II), Cu(II)) have been synthesised and their structures determined from single crystal X-ray diffraction data. Both compounds crystallize in the tetragonal system, space group P-42{sub 1}m. Their structures are formed from infinite sheets of linked oxopolyhedra of the stoichiometry [MP{sub 2}O{sub 7}]{sup 2−} with potassium cations situated between the layers. The MO{sub 4} tetrahedra share oxygen atoms with [P{sub 2}O{sub 7}]{sup 4−} diphosphate groups and the potassium ions have KO{sub 8} square prismatic geometry. In both compounds the M(II) centre has an unusual strongly flattened, tetrahedral coordination to oxygen, as a result of the Jahn–Teller (JT) effect for the high spin d{sup 6} Fe(II) and p-orbital mixing or a second order JT effect for d{sup 9} Cu(II) centres in four fold coordination. The uncommon transition metal ion environments found in these materials are reflected in their optical absorption spectra and magnetism data. - Graphical abstract: The structures of the tetragonal polymorphs of K{sub 2}MP{sub 2}O{sub 7}, M=Cu(II), Fe(II), consist of infinite sheets of stoichiometry [MP{sub 2}O{sub 7}]{sup 2−}, formed from linked pyrophosphate groups and MO{sub 4} tetrahedra, separated by potassium ions. In both compounds the unusual tetrahedral coordination of the M(II) centre is strongly flattened as a result of Jahn–Teller (JT) effects for high spin, d{sup 6} Fe(II) and p-orbital mixing and second-order JT effects for d{sup 9} Cu(II). Display Omitted - Highlights: • Tetrahedral copper and iron(II) coordinated by oxygen. • New layered phosphate structure. • Jahn–Teller and d{sup 10} distorted coordinations.

  1. The ALPHA antihydrogen trapping apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Amole, C. [Department of Physics and Astronomy, York University, Toronto ON Canada, M3J 1P3 (Canada); Andresen, G.B. [Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C (Denmark); Ashkezari, M.D. [Department of Physics, Simon Fraser University, Burnaby, BC Canada, V5A 1S6 (Canada); Baquero-Ruiz, M. [Department of Physics, University of California at Berkeley, Berkeley, CA 94720-7300 (United States); Bertsche, W. [Department of Physics, College of Science, Swansea University, Swansea SA2 8PP (United Kingdom); School of Physics and Astronomy, University of Manchester, Manchester M13 9PL (United Kingdom); The Cockcroft Institute, Warrington WA4 4AD (United Kingdom); Bowe, P.D. [Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C (Denmark); Butler, E. [Physics Department, CERN, CH-1211 Geneva 23 (Switzerland); Capra, A. [Department of Physics and Astronomy, York University, Toronto ON Canada, M3J 1P3 (Canada); Carpenter, P.T. [Department of Physics, Auburn University, Auburn, AL 36849-5311 (United States); Cesar, C.L. [Instituto de Física, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-972 (Brazil); Chapman, S. [Department of Physics, University of California at Berkeley, Berkeley, CA 94720-7300 (United States); Charlton, M.; Deller, A.; Eriksson, S. [Department of Physics, College of Science, Swansea University, Swansea SA2 8PP (United Kingdom); Escallier, J. [Brookhaven National Laboratory, Upton, NY 11973 (United States); Fajans, J. [Department of Physics, University of California at Berkeley, Berkeley, CA 94720-7300 (United States); Friesen, T. [Department of Physics and Astronomy, University of Calgary, Calgary AB, Canada, T2N 1N4 (Canada); Fujiwara, M.C.; Gill, D.R. [TRIUMF, 4004 Wesbrook Mall, Vancouver BC, Canada V6T 2A3 (Canada); Gutierrez, A. [Department of Physics and Astronomy, University of British Columbia, Vancouver BC, Canada V6T 1Z4 (Canada); and others

    2014-01-21

    The ALPHA collaboration, based at CERN, has recently succeeded in confining cold antihydrogen atoms in a magnetic minimum neutral atom trap and has performed the first study of a resonant transition of the anti-atoms. The ALPHA apparatus will be described herein, with emphasis on the structural aspects, diagnostic methods and techniques that have enabled antihydrogen trapping and experimentation to be achieved.

  2. The Taxonomy of Blue Amorphous Galaxies. II. Structure and Evolution

    Science.gov (United States)

    Marlowe, Amanda T.; Meurer, Gerhardt R.; Heckman, Timothy M.

    1999-09-01

    Dwarf galaxies play an important role in our understanding of galaxy formation and evolution, and starbursts are believed to affect the structure and evolution of dwarf galaxies strongly. We have therefore embarked on a systematic study of 12 of the nearest dwarf galaxies thought to be undergoing bursts of star formation. These were selected primarily by their morphological type (blue ``amorphous'' galaxies). We show that these blue amorphous galaxies are not physically distinguishable from dwarfs selected as starbursting by other methods, such as blue compact dwarfs (BCDs) and H II galaxies. All these classes exhibit surface brightness profiles that are exponential in the outer regions (r>~1.5re) but often have a predominantly central blue excess, suggesting a young burst in an older, redder galaxy. Typically, the starbursting ``cores'' are young (~107-108 yr) events compared to the older (~109-1010 yr) underlying galaxy (the ``envelope''). The ratio of the core to envelope in blue light ranges from essentially zero to about 2. These starbursts are therefore modest events involving only a few percent of the stellar mass. The envelopes have surface brightnesses that are much higher than typical dwarf irregular (dI) galaxies, so it is unlikely that there is a straightforward evolutionary relation between typical dIs and dwarf starburst galaxies. Instead we suggest that amorphous galaxies may repeatedly cycle through starburst and quiescent phases, corresponding to the galaxies with strong and weak/absent cores, respectively. Once amorphous galaxies use up the available gas (either through star formation or galactic winds) so that star formation is shut off, the faded remnants would strongly resemble dwarf elliptical galaxies. However, in the current cosmological epoch, this is evidently a slow process that is the aftermath of a series of many weak, recurring bursts. Present-day dE's must have experienced more rapid and intense evolution than this in the distant past.

  3. Discovery of deep and shallow trap states from step structures of rutile TiO2 vicinal surfaces by second harmonic and sum frequency generation spectroscopy

    International Nuclear Information System (INIS)

    Takahashi, Hiroaki; Watanabe, Ryosuke; Miyauchi, Yoshihiro; Mizutani, Goro

    2011-01-01

    In this report, local electronic structures of steps and terraces on rutile TiO 2 single crystal faces were studied by second harmonic and sum frequency generation (SHG/SFG) spectroscopy. We attained selective measurement of the local electronic states of the step bunches formed on the vicinal (17 18 1) and (15 13 0) surfaces using a recently developed step-selective probing technique. The electronic structures of the flat (110)-(1x1) (the terrace face of the vicinal surfaces) and (011)-(2x1) surfaces were also discussed. The SHG/SFG spectra showed that step structures are mainly responsible for the formation of trap states, since significant resonances from the trap states were observed only from the vicinal surfaces. We detected deep hole trap (DHT) states and shallow electron trap (SET) states selectively from the step bunches on the vicinal surfaces. Detailed analysis of the SHG/SFG spectra showed that the DHT and SET states are more likely to be induced at the top edges of the step bunches than on their hillsides. Unlike the SET states, the DHT states were observed only at the step bunches parallel to [1 1 1][equivalent to the step bunches formed on the (17 18 1) surface]. Photocatalytic activity for each TiO 2 sample was also measured through methylene blue photodegradation reactions and was found to follow the sequence: (110) < (17 18 1) < (15 13 0) < (011), indicating that steps along [0 0 1] are more reactive than steps along [1 1 1]. This result implies that the presence of the DHT states observed from the step bunches parallel to [1 1 1] did not effectively contribute to the methylene blue photodegradation reactions.

  4. Ripple Trap

    Science.gov (United States)

    2006-01-01

    3 April 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the margin of a lava flow on a cratered plain in the Athabasca Vallis region of Mars. Remarkably, the cratered plain in this scene is essentially free of bright, windblown ripples. Conversely, the lava flow apparently acted as a trap for windblown materials, illustrated by the presence of the light-toned, wave-like texture over much of the flow. That the lava flow surface trapped windblown sand and granules better than the cratered plain indicates that the flow surface has a rougher texture at a scale too small to resolve in this image. Location near: 10.7oN, 204.5oW Image width: 3 km (1.9 mi) Illumination from: lower left Season: Northern Winter

  5. Crystal structures of salicylideneguanylhydrazinium chloride and its copper(II) and cobalt(III) chloride complexes

    International Nuclear Information System (INIS)

    Chumakov, Yu. M.; Tsapkov, V. I.; Bocelli, G.; Antosyak, B. Ya.; Shova, S. G.; Gulea, A. P.

    2006-01-01

    The crystal structures of salicylideneguanylhydrazinium chloride hydrate hemiethanol solvate (I), salicylideneguanylhydrazinium trichloroaquacuprate(II) (II), and bis(salicylideneguanylhydrazino)cobalt(III) chloride trihydrate (III) are determined using X-ray diffraction. The structures of compounds I, II, and III are solved by direct methods and refined using the least-squares procedure in the anisotropic approximation for the non-hydrogen atoms to the final factors R = 0.0597, 0.0212, and 0.0283, respectively. In the structure of compound I, the monoprotonated molecules and chlorine ions linked by hydrogen bonds form layers aligned parallel to the (010) plane. In the structure of compound II, the salicylaldehyde guanylhydrazone cations and polymer chains consisting of trichloroaquacuprate(II) anions are joined by an extended three-dimensional network of hydrogen bonds. In the structure of compound III, the [Co(LH) 2 ] + cations, chloride ions, and molecules of crystallization water are linked together by a similar network

  6. Trapped antihydrogen

    CERN Document Server

    Butler, E; Ashkezari, M D; Baquero-Ruiz, M; Bertsche, W; Bowe, P D; Cesar, C L; Chapman, S; Charlton, M; Deller, A; Eriksson, S; Fajans, J; Friesen, T; Fujiwara, M C; Gill, D R; Gutierrez, A; Hangst, J S; Hardy, W N; Hayden, M E; Humphries, A J; Hydomako, R; Jenkins, M J; Jonsell, S; Jørgensen, L V; Kemp, S L; Kurchaninov, L; Madsen, N; Menary, S; Nolan, P; Olchanski, K; Olin, A; Povilus, A; Pusa, P; Rasmussen, C Ø; Robicheaux, F; Sarid, E; Seif el Nasr, S; Silveira, D M; So, C; Storey, J W; Thompson, R I; van der Werf, D P; Wurtele, J S; Yamazaki,Y

    2012-01-01

    Precision spectroscopic comparison of hydrogen and antihydrogen holds the promise of a sensitive test of the Charge-Parity-Time theorem and matter-antimatter equivalence. The clearest path towards realising this goal is to hold a sample of antihydrogen in an atomic trap for interrogation by electromagnetic radiation. Achieving this poses a huge experimental challenge, as state-of-the-art magnetic-minimum atom traps have well depths of only ∼1 T (∼0.5 K for ground state antihydrogen atoms). The atoms annihilate on contact with matter and must be ‘born’ inside the magnetic trap with low kinetic energies. At the ALPHA experiment, antihydrogen atoms are produced from antiprotons and positrons stored in the form of non-neutral plasmas, where the typical electrostatic potential energy per particle is on the order of electronvolts, more than 104 times the maximum trappable kinetic energy. In November 2010, ALPHA published the observation of 38 antiproton annihilations due to antihydrogen atoms that had been ...

  7. Trapping dynamics of isobutane, n-butane, and neopentane on Pt(111): Effects of molecular weight and structure

    International Nuclear Information System (INIS)

    Weaver, J.F.; Madix, R.J.

    1999-01-01

    The molecular adsorption dynamics of isobutane, n-butane, and neopentane on Pt(111) was investigated using supersonic molecular beam techniques and stochastic trajectory calculations. Using the united atom approach, a single, pairwise-additive Morse Potential for methyl (methylene)- plantinum interactions quantitatively simulates the dependence of the initial trapping probability, α, on the initial translational energy, E T , and angle of incidence, θ i , for each alkane. For both isobutane and n-butane, the dependence of α on E T and θ i best scales with E T cos 0.8 θ i , which is similar to that found previously for ethane and propane trapping on Pt(111). The initial trapping probability of neopentane exhibits a more pronounced dependence on θ i , which scales according to E T cos 1.3 θ i . The simulations suggest that the enhanced angular dependence of α for neopentane is related to its molecular weight. As the mass of the incident species is increased, momentum transfer to the surface becomes more efficient than the interconversion of incident parallel and normal momentum due to corrugation of the surface potential. The net effect is an increase in the trapping probability at glancing incidence compared to lighter molecules, and a resulting shift in the angular dependence of α towards normal energy scaling. The calculations also predict that collisional energy transfer to rotation is important in promoting adsorption. For each molecule, rotational excitation is determined to be the most effective energy transfer process that discriminates trapping from scattering. In addition, translational energy transfer to torsional vibration about the central C - C bond is highly efficient for n-butane, and greatly facilitates adsorption. Less excitation is predicted for C - C - C bending modes for all of these molecules. copyright 1999 American Institute of Physics

  8. Effect of oxide charge trapping on x-ray photoelectron spectroscopy of HfO2/SiO2/Si structures

    International Nuclear Information System (INIS)

    Abe, Yasuhiro; Miyata, Noriyuki; Suzuki, Haruhiko; Kitamura, Koji; Igarashi, Satoru; Nohira, Hiroshi; Ikenaga, Eiji

    2009-01-01

    We examined the effects of interfacial SiO 2 layers and a surface metal layer on the photoelectron spectra of HfO 2 /SiO 2 /Si structures by hard X-ray photoemission spectroscopy with synchrotron radiation as well as conventional X-ray photoelectron spectroscopy (XPS). The Hf 4f and Hf 3d photoelectron peaks broadened and shifted toward a higher binding energy with increasing thickness of the interfacial SiO 2 layer, even though photoelectrons may have been emitted from the HfO 2 layer with the same chemical composition. Thinning the interfacial Si oxide layer to approximately one monolayer and depositing a metal layer on the HfO 2 surface suppressed these phenomena. The O 1s photoelectron spectra revealed marked differences between the metal- and nonmetal-deposited HfO 2 /SiO 2 /Si structures; HfO 2 and SiO 2 components in the O 1s photoelectron spectra for the metal-deposited structures were observed at reasonably separated binding energies, but those for the nonmetal-deposited structures were not separated clearly. From this behavior concerning the effects of interfacial SiO 2 and surface metal layers, we concluded that the Hf 4f, Hf 3d, and O 1s spectra measured from the HfO 2 /SiO 2 /Si structures did not reflect actual chemical bonding states. We consider that potential variations in the HfO 2 film owing to charge trapping strongly affect the measured photoelectron spectra. On the basis of angle-resolved XPS measurements, we propose that positive charges are trapped at the HfO 2 surface and negative charges are trapped inside the HfO 2 layer. (author)

  9. New Mn(II, Ni(II, Cd(II, Pb(II complexes with 2-methylbenzimidazole and other ligands. Synthesis, spectroscopic characterization, crystal structure, magnetic susceptibility and biological activity studies

    Directory of Open Access Journals (Sweden)

    Shayma A. Shaker

    2016-11-01

    Full Text Available Synthesis and characterization of Mn(II, Ni(II, Cd(II and Pb(II mixed ligand complexes of 2-methylbenzimidazole with other ligands have been reported. The structure of the ligands and their complexes was investigated using elemental analysis, IR, UV–Vis, (1H, 13C NMR spectroscopy, molar conductivity and magnetic susceptibility measurements. In all the studies of complexes, the 2-methylbenzimidazole behaves as a neutral monodentate ligand which is coordinated with the metal ions through the N atom. While benzotriazole behaves as a neutral bidentate ligand which is coordinated with the Ni(II ion through the two N atoms. Moreover, the N-acetylglycine behaves as a bidentate ligand which is coordinated with the Mn(II, Ni(II and Pb(II ions through the N atom and the terminal carboxyl oxygen atom. The magnetic and spectral data indicate the tetrahedral geometry for Mn(II complex, irregular tetrahedral geometry for Pb(II complex and octahedral geometry for Ni(II complex. The X-ray single crystal diffraction method was used to confirm a centrosymmetric dinuclear Cd(II complex as each two metal ions are linked by a pair of thiocyanate N = S bridge. Two 2-methylbenzimidazole N-atom donors and one terminal thiocyanate N atom complete a highly distorted square pyramid geometry around the Cd atom. Besides, different cell types were used to determine the inhibitory effect of Mn(II, Ni(II, Cd(II and Pb(II complexes on cell growth using MTT assay. Cd(II complex showed cytotoxic effect on various types of cancer cell lines with different EC50 values.

  10. Metal Matrix Composite Enchanced Aluminum Structures, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed research pursues a path for reducing structural weight, increasing structural performance, and reducing fabrication cost while also minimizing...

  11. Zno Micro/Nanostructures Grown on Sapphire Substrates Using Low-Temperature Vapor-Trapped Thermal Chemical Vapor Deposition: Structural and Optical Properties

    Directory of Open Access Journals (Sweden)

    Po-Sheng Hu

    2017-12-01

    Full Text Available In this research, the Zn(C5H7O22·xH2O-based growth of ZnO micro/nanostructures in a low temperature, vapor-trapped chemical vapor deposition system was attempted to optimize structural and optical properties for potential biomedical applications. By trapping in-flow gas molecules and Zinc vapor inside a chamber tube by partially obstructing a chamber outlet, a high pressure condition can be achieved, and this experimental setup has the advantages of ease of synthesis, being a low temperature process, and cost effectiveness. Empirically, the growth process proceeded under a chamber condition of an atmospheric pressure of 730 torr, a controlled volume flow rate of input gas, N2/O2, of 500/500 Standard Cubic Centimeters per Minute (SCCM, and a designated oven temperature of 500 °C. Specifically, the dependence of structural and optical properties of the structures on growth duration and spatially dependent temperature were investigated utilizing scanning electron microscopy, X-ray diffraction (XRD, photoluminescence (PL, and ultraviolet-visible transmission spectroscopy. The experimental results indicate that the grown thin film observed with hexagonal structures and higher structural uniformity enables more prominent structural and optical signatures. XRD spectra present the dominant peaks along crystal planes of (002 and (101 as the main direction of crystallization. In addition, while the structures excited with laser wavelength of 325 nm emit a signature radiation around 380 nm, an ultraviolet lamp with a wavelength of 254 nm revealed distinctive photoluminescence peaks at 363.96 nm and 403.52 nm, elucidating different degrees of structural correlation as functions of growth duration and the spatial gradient of temperature. Transmittance spectra of the structures illustrate typical variation in the wavelength range of 200 nm to 400 nm, and its structural correlation is less significant when compared with PL.

  12. Camera Traps on Wildlife Crossing Structures as a Tool in Gray Wolf (Canis lupus) Management - Five-Years Monitoring of Wolf Abundance Trends in Croatia.

    Science.gov (United States)

    Šver, Lidija; Bielen, Ana; Križan, Josip; Gužvica, Goran

    2016-01-01

    The conservation of gray wolf (Canis lupus) and its coexistence with humans presents a challenge and requires continuous monitoring and management efforts. One of the non-invasive methods that produces high-quality wolf monitoring datasets is camera trapping. We present a novel monitoring approach where camera traps are positioned on wildlife crossing structures that channel the animals, thereby increasing trapping success and increasing the cost-efficiency of the method. In this way we have followed abundance trends of five wolf packs whose home ranges are intersected by a motorway which spans throughout the wolf distribution range in Croatia. During the five-year monitoring of six green bridges we have recorded 28 250 camera-events, 132 with wolves. Four viaducts were monitored for two years, recording 4914 camera-events, 185 with wolves. We have detected a negative abundance trend of the monitored Croatian wolf packs since 2011, especially severe in the northern part of the study area. Further, we have pinpointed the legal cull as probable major negative influence on the wolf pack abundance trends (linear regression, r2 > 0.75, P Croatia until there is more data proving population stability. In conclusion, quantitative methods, such as the one presented here, should be used as much as possible when assessing wolf abundance trends.

  13. Syntheses, structures and luminescence behaviour of some zinc(II ...

    Indian Academy of Sciences (India)

    2, the zinc(II) centre is bound by four N atoms of the tailored Schiff base L2 and two O atoms of the chelated acetate. .... determination parameters for 1 and 2 is given in table 1. 3. Results ..... Shields G P, Taylor R, Towler M and van de Streek J.

  14. Synthesis and structure of copper(II) complexes: Potential cyanide ...

    Indian Academy of Sciences (India)

    easy accessibility to Cu(I), Cu(II) and Cu(III) oxidation states.3,20–38 ... erty to oxidize primary alcohol to aldehyde since they are potential N,O ... Electronic spectra were recorded on a. Shimadzu .... the appropriate temperature 37. ◦. C for 24h.

  15. Spin–Orbit TDDFT Electronic Structure of Diplatinum(II,II) Complexes

    Czech Academy of Sciences Publication Activity Database

    Záliš, Stanislav; Lam, Y.; Ch.; Gray, H. B.; Vlček, Antonín

    2015-01-01

    Roč. 54, č. 7 (2015), s. 3491-3500 ISSN 0020-1669 R&D Projects: GA MŠk LH13015 Institutional support: RVO:61388955 Keywords : BINUCLEAR PLATINUM(II) PHOTOCHEMISTRY * DENSITY-FUNCTIONAL THEORY * SPECTROSCOPIC PROPERTIES Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.820, year: 2015

  16. Investigation of detergent effects on the solution structure of spinach Light Harvesting Complex II

    Energy Technology Data Exchange (ETDEWEB)

    Cardoso, Mateus B; Smolensky, Dmitriy; Heller, William T; O' Neill, Hugh, E-mail: hellerwt@ornl.gov, E-mail: oneillhm@ornl.gov [Center for Structural Molecular Biology, Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

    2010-11-01

    The properties of spinach light harvesting complex II (LHC II), stabilized in the detergents Triton X-100 (TX100) and n-Octyl-{beta}-D-Glucoside (BOG), were investigated by small-angle neutron scattering (SANS). The LHC II-BOG scattering curve overlaid well with the theoretical scattering curve generated from the crystal structure of LHC II indicating that the protein preparation was in its native functional state. On the other hand, the simulated LHC II curve deviated significantly from the LHC II-TX100 experimental data. Analysis by circular dichroism spectroscopy supported the SANS analysis and showed that LHC II-TX100 is inactivated. This investigation has implications for extracting and stabilizing photosynthetic membrane proteins for the development of biohybrid photoconversion devices.

  17. Dynamics of plasma−dust structures formed in a trap created in the narrowing of a current channel in a magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Dzlieva, E. S., E-mail: plasmadust@yandex.ru; Karasev, V. Yu., E-mail: v.karasev@spbu.ru; Pavlov, S. I. [St. Petersburg State University (Russian Federation)

    2016-02-15

    The geometry and dynamics of plasma−dust structures in a longitudinal magnetic field is studied experimentally. The structures are formed in a glow-discharge trap created in the double electric layer produced as a result of discharge narrowing by means of a dielectric insert introduced in the discharge tube. Studies of structures formed in the new type of glow-discharge trap are of interest from the standpoint of future experiments with complex plasmas in superstrong magnetic fields in which the dust component is magnetized. Different types of dielectric inserts were used: conical and plane ones with symmetric and asymmetric apertures. Conditions for the existence of stable dust structures are determined for dust grains of different density and different dispersity. According to the experimental results, the angular velocity of dust rotation is ≥10 s{sup –1}, which is the fastest type of dust motion for all types of discharges in a magnetic field. The rotation is interpreted by analyzing the dynamics of individual dust grains.

  18. Copper(II) and palladium(II) complexes with tridentate NSO donor Schiff base ligand: Synthesis, characterization and structures

    Science.gov (United States)

    Kumar, Sujit Baran; Solanki, Ankita; Kundu, Suman

    2017-09-01

    Mononuclear copper(II) complex [CuL2] and palladium(II) complexes [Pd(X)L] where X = benzoate(bz) or salicylate(sal) and HL = 2-(methylthio)phenylimino)methyl)phenol, a Schiff base ligand with NSO coordination sites have been synthesized and characterized by microanalyses, IR, UV-Visible spectra, conductivity measurement and magnetic studies. Crystal structures of all the complexes have been solved by single crystal X-ray diffraction studies and showed that there are two molecules in a unit cell in the [CuL2] complex - one molecule has square planar geometry whereas second molecule has distorted square pyramidal geometry and palladium(II) complexes have distorted square planar geometry.

  19. Influence of trap location on the efficiency of trapping in dendrimers and regular hyperbranched polymers.

    Science.gov (United States)

    Lin, Yuan; Zhang, Zhongzhi

    2013-03-07

    The trapping process in polymer systems constitutes a fundamental mechanism for various other dynamical processes taking place in these systems. In this paper, we study the trapping problem in two representative polymer networks, Cayley trees and Vicsek fractals, which separately model dendrimers and regular hyperbranched polymers. Our goal is to explore the impact of trap location on the efficiency of trapping in these two important polymer systems, with the efficiency being measured by the average trapping time (ATT) that is the average of source-to-trap mean first-passage time over every staring point in the whole networks. For Cayley trees, we derive an exact analytic formula for the ATT to an arbitrary trap node, based on which we further obtain the explicit expression of ATT for the case that the trap is uniformly distributed. For Vicsek fractals, we provide the closed-form solution for ATT to a peripheral node farthest from the central node, as well as the numerical solutions for the case when the trap is placed on other nodes. Moreover, we derive the exact formula for the ATT corresponding to the trapping problem when the trap has a uniform distribution over all nodes. Our results show that the influence of trap location on the trapping efficiency is completely different for the two polymer networks. In Cayley trees, the leading scaling of ATT increases with the shortest distance between the trap and the central node, implying that trap's position has an essential impact on the trapping efficiency; while in Vicsek fractals, the effect of location of the trap is negligible, since the dominant behavior of ATT is identical, respective of the location where the trap is placed. We also present that for all cases of trapping problems being studied, the trapping process is more efficient in Cayley trees than in Vicsek fractals. We demonstrate that all differences related to trapping in the two polymer systems are rooted in their underlying topological structures.

  20. Identifying the distinct features of geometric structures for hole trapping to generate radicals on rutile TiO₂(110) in photooxidation using density functional theory calculations with hybrid functional.

    Science.gov (United States)

    Wang, Dong; Wang, Haifeng; Hu, P

    2015-01-21

    Using density functional theory calculations with HSE 06 functional, we obtained the structures of spin-polarized radicals on rutile TiO2(110), which is crucial to understand the photooxidation at the atomic level, and further calculate the thermodynamic stabilities of these radicals. By analyzing the results, we identify the structural features for hole trapping in the system, and reveal the mutual effects among the geometric structures, the energy levels of trapped hole states and their hole trapping capacities. Furthermore, the results from HSE 06 functional are compared to those from DFT + U and the stability trend of radicals against the number of slabs is tested. The effect of trapped holes on two important steps of the oxygen evolution reaction, i.e. water dissociation and the oxygen removal, is investigated and discussed.

  1. Structure and Chromosomal Organization of Yeast Genes Regulated by Topoisomerase II.

    Science.gov (United States)

    Joshi, Ricky S; Nikolaou, Christoforos; Roca, Joaquim

    2018-01-03

    Cellular DNA topoisomerases (topo I and topo II) are highly conserved enzymes that regulate the topology of DNA during normal genome transactions, such as DNA transcription and replication. In budding yeast, topo I is dispensable whereas topo II is essential, suggesting fundamental and exclusive roles for topo II, which might include the functions of the topo IIa and topo IIb isoforms found in mammalian cells. In this review, we discuss major findings of the structure and chromosomal organization of genes regulated by topo II in budding yeast. Experimental data was derived from short (10 min) and long term (120 min) responses to topo II inactivation in top-2 ts mutants. First, we discuss how short term responses reveal a subset of yeast genes that are regulated by topo II depending on their promoter architecture. These short term responses also uncovered topo II regulation of transcription across multi-gene clusters, plausibly by common DNA topology management. Finally, we examine the effects of deactivated topo II on the elongation of RNA transcripts. Each study provides an insight into the particular chromatin structure that interacts with the activity of topo II. These findings are of notable clinical interest as numerous anti-cancer therapies interfere with topo II activity.

  2. Synthesis, crystal structures and properties of new homoleptic Ni(II)/Pd(II) β-oxodithioester chelates

    Science.gov (United States)

    Yadav, Chote L.; Manar, Krishna K.; Yadav, Manoj K.; Tiwari, Neeraj; Singh, Rakesh K.; Drew, Michael G. B.; Singh, Nanhai

    2018-05-01

    Six new cis-chelate complexes, [M(L)2] (L = methyl-3-hydroxy-3-(furyl)-2-propenedithioate L1, M = Ni(II) 1, Pd(II) 4; methyl-3-hydroxy-3-(thiophenyl)-2-propenedithioate L2, M = Ni(II) 2, Pd(II) 5 and methyl-3-hydroxy-3-(phenyl)-2-propenedithioate L3, M = Ni(II) 3, Pd(II) 6 have been prepared and characterized by elemental analyses, spectroscopy (IR, UV-Vis., 1H and 13C{1H} NMR). The structures of 2-6 have been revealed by X-ray crystallography. In all the crystal structures, the metal has four-coordinate slightly distorted square planar geometry with a cis-configuration of the ligands. Anti-leishmanial properties of the complexes have been studied; 2, 3 and 6 showed potential anti-promastigote and anti-amastigote activities with IC50 values of 1.70 ± 0.50, 1.62 ± 0.19, 9.20 ± 2.16 μg/mL and IC50 2.50 ± 0.10, 2.05 ± 0.40, 12.84 ± 3.46 μg/mL respectively. Cytotoxicity assays on these complexes showed toxicity on the promastigotes but less toxicity against RAW 264.7 cell lines at different concentrations. Palladium complexes 4, 5 and 6 show luminescent characteristics in CH2Cl2 solution at room temperature. Complexes 1-6 are weakly conducting (σrt = 10-4-10-6 S cm-1, Ea = 0.19-1.13 eV) but show semiconducting behavior in the solid phase.

  3. Syntheses, crystal structures and spectroscopic properties of copper(II)-tetracyanometallate(II) complexes with nicotinamide and isonicotinamide ligands

    Science.gov (United States)

    Sayın, Elvan; Kürkçüoğlu, Güneş Süheyla; Yeşilel, Okan Zafer; Hökelek, Tuncer

    2015-09-01

    Four new one dimensional (1D) cyanide complexes, namely {[Cu(NH3)4(μ-na)][M‧(CN)4]}n and {[Cu(NH3)2(ina)2M‧(μ-CN)2(CN)2]}n (M‧(II) = Pd (1 and 3) or Pt (2 and 4), na:nicotinamide and ina:isonicotinamide) have been synthesized and characterized by elemental, spectral (FT-IR and Raman), and thermal (TG, DTG and DTA) analyses. The crystal structures of complexes 1-3 have been determined by single crystal X-ray diffraction technique. In complexes 1 and 2, na ligand is coordinated to the adjacent Cu(II) ions as a bridging ligand, giving rise to 1D linear cationic chain and the [M‧(CN)4]2- anionic complex acts as a counter ion. Complexes 3 and 4 are also 1D linear chain in which two cyanide ligands bridged neighboring M‧(II) and Cu(II) ions, while ina ligand is coordinated Cu(II) ion through nitrogen atom of pyridine ring. In the complexes, the Cu(II) ions adopt distorted octahedral geometries, while M‧(II) ions are four coordinated with four carbon atoms from cyanide ligands in square-planar geometries. The adjacent chains are further stacked through intermolecular hydrogen bond, Nsbnd Hṡṡṡπ, Csbnd H⋯M‧ and M‧⋯π interactions to form 3D supramolecular networks. Vibration assignments are given for all the observed bands. In addition, thermal stabilities of the compounds are also discussed.

  4. Reductive trapping of [(OC){sub 5}W-W(CO){sub 5}]{sup 2-} in a mixed-valent Sm{sup II/III} calix[4]pyrrolide sandwich

    Energy Technology Data Exchange (ETDEWEB)

    Deacon, Glen B.; Guo, Zhifang [School of Chemistry, Monash University, VIC (Australia); Junk, Peter C.; Wang, Jun [College of Science and Engineering, James Cook University, Townsville, QLD (Australia)

    2017-07-10

    Reduction of tungsten hexacarbonyl by the divalent samarium(II) complex [Sm{sub 2}(N{sub 4}Et{sub 8})(thf){sub 4}] ((N{sub 4}Et{sub 8}){sup 4-}=meso-octaethylcalix[4]pyrrolide) in toluene at ambient temperature gave the remarkable heteronuclear mixed-valent samarium(II/III)/tungsten complex [{(thf)_2Sm"I"I(N_4Et_8)Sm"I"I"I(thf)}{sub 2}{(μ-OC)_2W_2(CO)_8}], which features the trapping of a rare [W{sub 2}(CO){sub 10}]{sup 2-} anion with an unsupported W-W bond. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  5. New Cu (II), Co(II) and Ni(II) complexes of chalcone derivatives: Synthesis, X-ray crystal structure, electrochemical properties and DFT computational studies

    Science.gov (United States)

    Tabti, Salima; Djedouani, Amel; Aggoun, Djouhra; Warad, Ismail; Rahmouni, Samra; Romdhane, Samir; Fouzi, Hosni

    2018-03-01

    The reaction of nickel(II), copper(II) and cobalt(II) with 4-hydroxy-3-[(2E)-3-(1H-indol-3-yl)prop-2-enoyl]-6-methyl-2H-pyran-2-one (HL) leads to a series of new complexes: Ni(L)2(NH3), Cu(L)2(DMF)2 and Co(L)2(H2O). The crystal structure of the Cu(L)2(DMF)2 complex have been determined by X-ray diffraction methods. The Cu(II) lying on an inversion centre is coordinated to six oxygen atoms forming an octahedral elongated. Additionally, the electrochemical behavior of the metal complexes were investigated by cyclic voltammetry at a glassy carbon electrode (GC) in CH3CN solutions, showing the quasi-reversible redox process ascribed to the reduction of the MII/MI couples. The X-ray single crystal structure data of the complex was matched excellently with the optimized monomer structure of the desired compound; Hirschfeld surface analysis supported the packed crystal lattice 3D network intermolecular forces. HOMO/LUMO energy level and the global reactivity descriptors quantum parameters are also calculated. The electrophilic and nucleophilic potions in the complex surface are theoretically evaluated by molecular electrostatic potential and Mulliken atomic charges analysis.

  6. New manganese (II) structures derived from 2,6-dichlorobenzoic acid: Syntheses, crystal structures and magnetism

    International Nuclear Information System (INIS)

    Esteves, D.; Tedesco, J.C.D.; Pedro, S.S.; Cruz, C.; Reis, M.S.; Brandão, P.

    2014-01-01

    One novel coordination polymer [Mn 2 (μ-2,6-DCBA) 3 (μ 2 -CH 3 CO 2 ) 2 (2H 2 O)]·2H 2 O (2,6-DCBA = 2,6-dichlorobenzoato) (compound 1) has been synthesized by self-assembly of bridging ligand 2,6-dichlorobenzoic acid and manganese acetate tetrahydrate. Single crystal X-ray diffraction analysis reveals that this compound crystallizes in space group P2 1 /c with a = 10.1547(7), b = 24.5829(2), c = 12.6606(2) Å, β = 93.707(3), V = 3153.9(3) Å 3 and Z = 4. The Mn(II) ions are connected by 2,6-DCBA and acetate group in μ-bridging mode to form 1D chains. Two water molecules are in the inter-layer space forming strong hydrogen bonds originating 2D layer structure. The preparation of this compound is very sensitive to the synthesis conditions, mainly to the solution pH and solvent yielding other two compounds 2 and 3. In compound 1 Mn(II) atoms in octahedral coordination are arranged in a zig–zag chain, with a trimeric structure repeated periodically along the chain, giving two exchange parameters: J 1 related to a syn–syn bond; and J 2 related to a bond of type anti–anti. A theoretical model was developed and then fitted to the magnetic susceptibility data, revealing an antiferromagnetic arrangement along the chain

  7. Spin-trapping and ESR studies of the direct photolysis of aromatic amino acids, dipeptides, tripeptides and polypeptides in aqueous solutions-II. Tyrosine and related compounds

    Energy Technology Data Exchange (ETDEWEB)

    Lion, Y; Kuwabara, M; Riesz, P [National Cancer Inst., Bethesda, MD (USA)

    1982-01-01

    The UV-photolysis of peptides containing tyrosine (Tyr) was investigated in aqueous solutions at room temperature at 220 and 265 nm. The short-lived free radicals formed during photolysis were spin-trapped by t-nitrosobutane and identified by electron spin resonance. For N-acetyl-and N-formyl-L-Tyr and for peptides containing L-Tyr as the middle residue, photolysis at 265 nm under neutral conditions produced mainly spin-adducts due to the scission between the alpha carbon and the methylene group attached to the aromatic ring, while at 220 nm decarboxylation radicals were spin-trapped. Photolysis of di- and tripeptides at 275 nm in alkaline solutions predominantly generated deamination radicals. The radicals produced in the photolysis of the oxidized A chain of insulin were tentatively characterized by comparison with the results for di- and tripeptides.

  8. Nose Structure Delineation of Bouguer Anomaly as the Interpretation Basis of Probable Hydrocarbon Traps: A Case Study on the Mainland Area of Northwest Java Basin

    Directory of Open Access Journals (Sweden)

    Kamtono Kamtono

    2014-06-01

    Full Text Available DOI: 10.17014/ijog.v7i3.144Two important aspects in the exploration of oil and gas are technology and exploration concepts, but the use of technology is not always suitable for areas with geological conditions covered by young volcanic sediments or limestone. The land of the Northwest Java Basin is mostly covered by young volcanic products, so exploration using seismic methods will produce less clear image resolution. To identify and interpret the subsurface structure and the possibility of hydrocarbon trap, gravity measurements have been carried out. Delineation of nose structures of a Bouguer anomaly map was used to interpret the probability of hydrocarbon traps. The result of the study shows that the gravity anomalies could be categorized into three groups : low anomaly (< 34 mgal, middle anomaly (34 - 50 mgal, and high anomaly (> 50 mgal. The analysis of Bouguer anomaly indicates that the low anomaly is concentrated in Cibarusa area as a southern part of Ciputat Subbasin, and in Cikampek area. The result of delineation of the Bouguer anomaly map shows the nose structures existing on Cibinong-Cileungsi and Pangkalan-Bekasi Highs, while delineation of residual anomaly map shows the nose structures occurs on Cilamaya-Karawang high. Locally, the gas fields of Jatirangon and Cicauh areas exist on the flank of the nose structure of Pangkalan-Bekasi High, while the oil/gas field of Northern Cilamaya is situated on the flank of the nose structure of Cilamaya-Karawang High. The concept of fluid/gas migration concentrated on nose structures which are delineated from gravity data can be applied in the studied area. This concept needs to be tested in other oil and gas field areas.

  9. Syntheses, Crystal Structures and Thermal Behaviors of Two Supramolecular Salamo-Type Cobalt(II and Zinc(II Complexes

    Directory of Open Access Journals (Sweden)

    Gang Li

    2017-07-01

    Full Text Available This paper reports the syntheses of two new complexes, [Co(L1(H2O2] (1 and [{Zn(L2(μ-OAcZn(n-PrOH}2] (2, from asymmetric halogen-substituted Salamo-type ligands H2L1 and H3L2, respectively. Investigation of the crystal structure of complex 1 reveals that the complex includes one Co(II ion, one (L12− unit and two coordinated water molecules. Complex 1 shows slightly distorted octahedral coordination geometry, forming an infinite 2D supramolecular structure by intermolecular hydrogen bond and π–π stacking interactions. Complex 2 contains four Zn(IIions, two completely deprotonated (L23− moieties, two coordinated μ-OAc− ions and n-propanol molecules. The Zn(II ions in complex 2 display slightly distorted trigonal bipyramidal or square pyramidal geometries.

  10. Crystal structure of bis(N,N,N′,N′-tetramethylguanidinium tetrachloridocuprate(II

    Directory of Open Access Journals (Sweden)

    Mamadou Ndiaye

    2016-07-01

    Full Text Available In the structure of the title salt, (C5H14N32[CuCl4], the CuII atom in the anion lies on a twofold rotation axis. The tetrachloridocuprate(II anion adopts a flattened tetrahedral coordination environment and interacts electrostatically with the tetramethylguanidinium cation. The crystal packing is additionally consolidated through N—H...Cl and C—H...Cl hydrogen bonds, resulting in a three-dimensional network structure.

  11. Reflexive Aero Structures for Enhanced Survivability, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Cornerstone Research Group Inc. (CRG) will develop an advanced reflexive structure technology system to increase the survivability of future systems constructed of...

  12. Refractory Coated/Lined Low Density Structures, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — This project addresses the development of refractory coated or lined low density structures applicable for advanced future propulsion system technologies. The...

  13. Dissociation behavior of methane--ethane mixed gas hydrate coexisting structures I and II.

    Science.gov (United States)

    Kida, Masato; Jin, Yusuke; Takahashi, Nobuo; Nagao, Jiro; Narita, Hideo

    2010-09-09

    Dissociation behavior of methane-ethane mixed gas hydrate coexisting structures I and II at constant temperatures less than 223 K was studied with use of powder X-ray diffraction and solid-state (13)C NMR techniques. The diffraction patterns at temperatures less than 203 K showed both structures I and II simultaneously convert to Ih during the dissociation, but the diffraction pattern at temperatures greater than 208 K showed different dissociation behavior between structures I and II. Although the diffraction peaks from structure II decreased during measurement at constant temperatures greater than 208 K, those from structure I increased at the initial step of dissociation and then disappeared. This anomalous behavior of the methane-ethane mixed gas hydrate coexisting structures I and II was examined by using the (13)C NMR technique. The (13)C NMR spectra revealed that the anomalous behavior results from the formation of ethane-rich structure I. The structure I hydrate formation was associated with the dissociation rate of the initial methane-ethane mixed gas hydrate.

  14. Crystal structure of the sweet-tasting protein thaumatin II at 1.27 A

    International Nuclear Information System (INIS)

    Masuda, Tetsuya; Ohta, Keisuke; Tani, Fumito; Mikami, Bunzo; Kitabatake, Naofumi

    2011-01-01

    Highlights: → X-ray crystallographic structure of sweet-tasting protein, thaumatin II, was determined at a resolution of 1.27 A. → The overall structure of thaumatin II is similar to that of thaumatin I, but a slight shift of the Cα atom of G96 in thaumatin II was observed. → The side chain of two critical residues, 67 and 82, for sweetness was modeled in two alternative conformations. → The flexibility and fluctuation of side chains at 67 and 82 seems to be suitable for interaction of thaumatin molecules with sweet receptors. -- Abstract: Thaumatin, an intensely sweet-tasting protein, elicits a sweet taste sensation at 50 nM. Here the X-ray crystallographic structure of one of its variants, thaumatin II, was determined at a resolution of 1.27 A. Overall structure of thaumatin II is similar to thaumatin I, but a slight shift of the Cα atom of G96 in thaumatin II was observed. Furthermore, the side chain of residue 67 in thaumatin II is highly disordered. Since residue 67 is one of two residues critical to the sweetness of thaumatin, the present results suggested that the critical positive charges at positions 67 and 82 are disordered and the flexibility and fluctuation of these side chains would be suitable for interaction of thaumatin molecules with sweet receptors.

  15. Crystal structure of the sweet-tasting protein thaumatin II at 1.27 A

    Energy Technology Data Exchange (ETDEWEB)

    Masuda, Tetsuya, E-mail: t2masuda@kais.kyoto-u.ac.jp [Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto 611-0011 (Japan); Department Natural Resources, Graduate School of Global Environmental Studies, Kyoto University, Uji, Kyoto 611-0011 (Japan); Ohta, Keisuke; Tani, Fumito [Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto 611-0011 (Japan); Department Natural Resources, Graduate School of Global Environmental Studies, Kyoto University, Uji, Kyoto 611-0011 (Japan); Mikami, Bunzo [Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Uji, Kyoto 611-0011 (Japan); Kitabatake, Naofumi [Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto 611-0011 (Japan); Department Natural Resources, Graduate School of Global Environmental Studies, Kyoto University, Uji, Kyoto 611-0011 (Japan)

    2011-07-08

    Highlights: {yields} X-ray crystallographic structure of sweet-tasting protein, thaumatin II, was determined at a resolution of 1.27 A. {yields} The overall structure of thaumatin II is similar to that of thaumatin I, but a slight shift of the C{alpha} atom of G96 in thaumatin II was observed. {yields} The side chain of two critical residues, 67 and 82, for sweetness was modeled in two alternative conformations. {yields} The flexibility and fluctuation of side chains at 67 and 82 seems to be suitable for interaction of thaumatin molecules with sweet receptors. -- Abstract: Thaumatin, an intensely sweet-tasting protein, elicits a sweet taste sensation at 50 nM. Here the X-ray crystallographic structure of one of its variants, thaumatin II, was determined at a resolution of 1.27 A. Overall structure of thaumatin II is similar to thaumatin I, but a slight shift of the C{alpha} atom of G96 in thaumatin II was observed. Furthermore, the side chain of residue 67 in thaumatin II is highly disordered. Since residue 67 is one of two residues critical to the sweetness of thaumatin, the present results suggested that the critical positive charges at positions 67 and 82 are disordered and the flexibility and fluctuation of these side chains would be suitable for interaction of thaumatin molecules with sweet receptors.

  16. Surface Structures Formed by a Copper(II Complex of Alkyl-Derivatized Indigo

    Directory of Open Access Journals (Sweden)

    Akinori Honda

    2016-10-01

    Full Text Available Assembled structures of dyes have great influence on their coloring function. For example, metal ions added in the dyeing process are known to prevent fading of color. Thus, we have investigated the influence of an addition of copper(II ion on the surface structure of alkyl-derivatized indigo. Scanning tunneling microscope (STM analysis revealed that the copper(II complexes of indigo formed orderly lamellar structures on a HOPG substrate. These lamellar structures of the complexes are found to be more stable than those of alkyl-derivatized indigos alone. Furthermore, 2D chirality was observed.

  17. Molecular structure and DFT investigations on new cobalt(II ...

    Indian Academy of Sciences (India)

    tion process was demonstrated.9 Late-transition metals, especially Ni, Pd ..... in table S2 (Supplementary Information). Most of the ... to molecular system because of atomic charges affect ... structure, acidity–basicity behavior and other proper-.

  18. Poverty and Family Structure - Phase II | IDRC - International ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Understanding the dynamics of change in family structure is critical in poverty diagnosis, ... And, how could public social security be conceived to protect the most vulnerable? ... IDRC invites applications for the IDRC Research Awards 2019.

  19. Structural Integrity Inspection and Visualization System, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Based on the successful feasibility demonstration in Phase I, Physical Optics Corporation (POC) proposes to continue the development of a novel Structural Integrity...

  20. New Analysis and Theory of Deployable Folded Structures, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — A recently developed mathematical folding theory has great value for deployable space structures and in situ manufacture of large beams, panels and cylinders. The...

  1. Syntheses, structures and properties of two dinuclear mercury(II ...

    Indian Academy of Sciences (India)

    MS received 8 August 2013; revised 9 December 2013; accepted 22 ... Structures of both the compounds are solved by X-ray diffraction measurements. ... Elemental analyses (carbon, hydrogen and nitrogen) ..... Verschoor G C 1984 J. Chem.

  2. Quantifiable and Reliable Structural Health Management Systems, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Under Project Constellation, NASA is developing a new generation of spacecraft for human spaceflight. A significant percentage of the structures used in these...

  3. Rational assembly of Pb(II)/Cd(II)/Mn(II) coordination polymers based on flexible V-shaped dicarboxylate ligand: Syntheses, helical structures and properties

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Gao-Shan [School of Environment and Chemical Engineering, Nanchang Hangkong University, Nanchang 330063 (China); Liu, Chong-Bo, E-mail: cbliu@nchu.edu.cn [School of Environment and Chemical Engineering, Nanchang Hangkong University, Nanchang 330063 (China); School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332 (United States); Liu, Hong [School of Environment and Chemical Engineering, Nanchang Hangkong University, Nanchang 330063 (China); Robbins, Julianne; Zhang, Z. John [School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332 (United States); Yin, Hong-Shan [School of Environment and Chemical Engineering, Nanchang Hangkong University, Nanchang 330063 (China); Wen, Hui-Liang [State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047 (China); Wang, Yu-Hua [School of Environment and Chemical Engineering, Nanchang Hangkong University, Nanchang 330063 (China)

    2015-05-15

    Six new coordination polymers, namely, [Pb(L)(H{sub 2}O)] (1), [Pb(L)(phen)] (2), [Pb{sub 2}(L){sub 2}(4,4′-bipy){sub 0.5}] (3), [Cd(L)(phen)] (4), [Cd(L)(4,4′-bipy)]·H{sub 2}O (5) and [Mn(L)(4,4′-bipy)]·H{sub 2}O (6) have been synthesized by the hydrothermal reaction of 2,2′-[hexafluoroisopropylidenebis(p-phenyleneoxy)]diacetic acid (H{sub 2}L) with Pb(II)/Cd(II)/Mn(II) in the presence of ancillary ligands 4,4′-bipyridine (4,4′-bipy) or 1,10-phenanthroline (phen). Complexes 1 and 4–6 exhibit 2-D structures, and complexes 2–3 display 3-D frameworks, of which L{sup 2−} ligands join metal ions to single-stranded helical chains of 1, 3–6 and double-stranded helical chains of 2. Complexes 2 and 3 also contain double-stranded Metal–O helices. Topology analysis reveals that complexes 1 and 4 both represent 4-connected sql net, 2 represents 6-connected pcu net, 3 exhibits a novel (3,12)-connected net, while 5 and 6 display (3,5)-connected gek1 net. The six complexes exhibit two kinds of inorganic–organic connectivities: I{sup 0}O{sup 2} for 1, 4–6, and I{sup 1}O{sup 2} for 2–3. The photoluminescent properties of 4–5 and the magnetic properties of 6 have been investigated. - Graphical abstract: Six new Pb(II)/Cd(II)/Mn(II) coordination polymers with helical structures based on flexible V-shaped dicarboxylate ligand have been synthesized and structurally characterized. Photoluminescent and magnetic properties have been investigated. - Highlights: • Six novel M(II) coordination polymers with 2,2′-[hexafluoroisopropylidenebis(p-phenyleneoxy)]diacetic acid and N-donor ligands. • Complexes 1–6 show diverse intriguing helical characters. • The luminescent properties of complexes 1–5 were investigated. • Complex 6 shows antiferromagnetic coupling.

  4. Crystal structures of copper(II) chloride, copper(II) bromide, and copper(II) nitrate complexes with pyridine-2-carbaldehyde thiosemicarbazone

    Science.gov (United States)

    Chumakov, Yu. M.; Tsapkov, V. I.; Jeanneau, E.; Bairac, N. N.; Bocelli, G.; Poirier, D.; Roy, J.; Gulea, A. P.

    2008-09-01

    The crystal structures of chloro-(2-formylpyridinethiosemicarbazono)copper dimethyl sulfoxide solvate ( I), bromo-(2-formylpyridinethiosemicarbazono)copper ( II), and (2-formylpyridinethiosemicarbazono)copper(II) nitrate dimethyl sulfoxide solvate ( III) are determined using X-ray diffraction. In the crystals, complexes I and II form centrosymmetric dimers in which the thiosemicarbazone sulfur atom serves as a bridge and occupies the fifth coordination site of the copper atom of the neighboring complex related to the initial complex through the center of symmetry. In both cases, the coordination polyhedron of the complexing ion is a distorted tetragonal bipyramid. Complex III in the crystal structure forms polymer chains in which the copper atom of one complex forms the coordination bond with the thicarbamide nitrogen atom of the neighboring complex. In this structure, the coordination polyhedron of the central atom is an elongated tetragonal bipyramid. It is established that complexes I III at a concentration of 10-5 mol/l selectively inhibit the growth of 60 to 90 percent of the cancer tumor cells of the human myeloid leukemia (HL-60).

  5. Crystal structures of copper(II) chloride, copper(II) bromide, and copper(II) nitrate complexes with pyridine-2-carbaldehyde thiosemicarbazone

    International Nuclear Information System (INIS)

    Chumakov, Yu. M.; Tsapkov, V. I.; Jeanneau, E.; Bairac, N. N.; Bocelli, G.; Poirier, D.; Roy, J.; Gulea, A. P.

    2008-01-01

    The crystal structures of chloro-(2-formylpyridinethiosemicarbazono)copper dimethyl sulfoxide solvate (I), bromo-(2-formylpyridinethiosemicarbazono)copper (II), and (2-formylpyridinethiosemicarbazono)copper(II) nitrate dimethyl sulfoxide solvate (III) are determined using X-ray diffraction. In the crystals, complexes I and II form centrosymmetric dimers in which the thiosemicarbazone sulfur atom serves as a bridge and occupies the fifth coordination site of the copper atom of the neighboring complex related to the initial complex through the center of symmetry. In both cases, the coordination polyhedron of the complexing ion is a distorted tetragonal bipyramid. Complex III in the crystal structure forms polymer chains in which the copper atom of one complex forms the coordination bond with the thicarbamide nitrogen atom of the neighboring complex. In this structure, the coordination polyhedron of the central atom is an elongated tetragonal bipyramid. It is established that complexes I-III at a concentration of 10 -5 mol/l selectively inhibit the growth of 60 to 90 percent of the cancer tumor cells of the human myeloid leukemia (HL-60).

  6. Crystal structures of copper(II) chloride, copper(II) bromide, and copper(II) nitrate complexes with pyridine-2-carbaldehyde thiosemicarbazone

    Energy Technology Data Exchange (ETDEWEB)

    Chumakov, Yu. M., E-mail: chumakov.xray@phys.asm.md [Academy of Sciences of Moldova, Institute of Applied Physics (Moldova, Republic of); Tsapkov, V. I. [State University of Moldova (Moldova, Republic of); Jeanneau, E. [Universite Claude Bernard, Laboratoire des Multimateriaux et Interfaces (France); Bairac, N. N. [State University of Moldova (Moldova, Republic of); Bocelli, G. [National Research Council (IMEM-CNR), Institute of Materials for Electronics and Magnetism (Italy); Poirier, D.; Roy, J. [Centre Hospitalier Universitaire de Quebec (CHUQ) (Canada); Gulea, A. P. [State University of Moldova (Moldova, Republic of)

    2008-09-15

    The crystal structures of chloro-(2-formylpyridinethiosemicarbazono)copper dimethyl sulfoxide solvate (I), bromo-(2-formylpyridinethiosemicarbazono)copper (II), and (2-formylpyridinethiosemicarbazono)copper(II) nitrate dimethyl sulfoxide solvate (III) are determined using X-ray diffraction. In the crystals, complexes I and II form centrosymmetric dimers in which the thiosemicarbazone sulfur atom serves as a bridge and occupies the fifth coordination site of the copper atom of the neighboring complex related to the initial complex through the center of symmetry. In both cases, the coordination polyhedron of the complexing ion is a distorted tetragonal bipyramid. Complex III in the crystal structure forms polymer chains in which the copper atom of one complex forms the coordination bond with the thicarbamide nitrogen atom of the neighboring complex. In this structure, the coordination polyhedron of the central atom is an elongated tetragonal bipyramid. It is established that complexes I-III at a concentration of 10{sup -5} mol/l selectively inhibit the growth of 60 to 90 percent of the cancer tumor cells of the human myeloid leukemia (HL-60).

  7. Structure-preserving algorithms for oscillatory differential equations II

    CERN Document Server

    Wu, Xinyuan; Shi, Wei

    2015-01-01

    This book describes a variety of highly effective and efficient structure-preserving algorithms for second-order oscillatory differential equations. Such systems arise in many branches of science and engineering, and the examples in the book include systems from quantum physics, celestial mechanics and electronics. To accurately simulate the true behavior of such systems, a numerical algorithm must preserve as much as possible their key structural properties: time-reversibility, oscillation, symplecticity, and energy and momentum conservation. The book describes novel advances in RKN methods, ERKN methods, Filon-type asymptotic methods, AVF methods, and trigonometric Fourier collocation methods.  The accuracy and efficiency of each of these algorithms are tested via careful numerical simulations, and their structure-preserving properties are rigorously established by theoretical analysis. The book also gives insights into the practical implementation of the methods. This book is intended for engineers and sc...

  8. Electronic Structure of Rare-Earth Metals. II. Positron Annihilation

    DEFF Research Database (Denmark)

    Williams, R. W.; Mackintosh, Allan

    1968-01-01

    of Loucks shows that the independent-particle model gives a good first approximation to the angular distribution, although correlation effects probably smear out some of the structure. The angular distributions from the heavy rare-earth metals are very similar to that from Y and can be understood....... In the spiral phase of Ho, the structure in the c-axis distribution is much reduced, indicating that the Fermi surface is substantially modified by the magnetic ordering, as expected. The photon distribution from the equiatomic Ho-Er alloy is very similar to those from the constituent metals, although...

  9. Structural equations for Killing tensors of order two. II

    International Nuclear Information System (INIS)

    Hauser, I.; Malhiot, R.J.

    1975-01-01

    In a preceding paper, a new form of the structural equations for any Killing tensor of order two have been derived; these equations constitute a system analogous to the Killing vector equations Nabla/sub alpha/ K/sub beta/ = ω/sub alpha beta/ = -ω/sub beta alpha/ and Nabla/sub gamma/ ω/sub alpha beta = R/sub alpha beta gamma delta/ K/sup delta/. The first integrability condition for the Killing tensor structural equations is now derived. The structural equations and the integrability condition have forms which can readily be expressed in terms of a null tetrad to furnish a Killing tensor parallel of the Newman--Penrose equations; this is briefly described. The integrability condition implies the new result, for any given space--time, that the dimension of the set of second-order Killing tensors attains its maximum possible value of 50 only if the space--time is of constant curvature. Potential applications of the structural equations are discussed

  10. Crystal structure of cis-tetraaquadichloridocobalt(II sulfolane disolvate

    Directory of Open Access Journals (Sweden)

    Mhamed Boudraa

    2015-02-01

    Full Text Available In the title compound, [CoCl2(H2O4]·2C4H8SO2, the CoII cation is located on the twofold rotation axis and is coordinated by four water molecules and two adjacent chloride ligands in a slightly distorted octahedral coordination environment. The cisoid angles are in the range 83.27 (5–99.66 (2°. The three transoid angles deviate significantly from the ideal linear angle. The crystal packing can be described as a linear arrangement of complex units along c formed by bifurcated O—H...Cl hydrogen bonds between two water molecules from one complex unit towards one chloride ligand of the neighbouring complex. Two solvent molecules per complex are attached to this infinite chain via O—H...O hydrogen bonds in which water molecules act as the hydrogen-bond donor and sulfolane O atoms as the hydrogen-bond acceptor sites.

  11. Structural studies on a non-toxic homologue of type II RIPs from ...

    Indian Academy of Sciences (India)

    Structural studies on a non-toxic homologue of type II RIPs from bitter gourd: Molecular basis of non-toxicity, conformational selection and glycan structure. MS accepted http://www.ias.ac.in/jbiosci. THYAGESHWAR CHANDRAN, ALOK SHARMA and M VIJAYAN. J. Biosci. 40(5), October 2015, 929–941, © Indian Academy of ...

  12. I. Structural studies of termite defense secretions. II. Structural studies of natural products of marine nudibranchs. [Kempene, tridachione

    Energy Technology Data Exchange (ETDEWEB)

    Solheim, B.A.

    1977-12-01

    Three families of termites have the ability to produce a sticky secretion that envelopes and immobilizes the enemy. In the family Termitidae the secretion contains the diterpenoid hydrocarbons, kempene I and kempene II. The molecular structure of kempene II from the termite, Nasutitermes kempae, is described in detail. Another species of termite, Cubitermes umbratus, contained the diterpenoid hydrocarbon biflora-4,10-19,15-triene in the secretion and this compound is described. Studies were also conducted on the mucous secretion of the pedal gland of the marine nudibranch, Tidachiella diomedea. Tridachione, a substituted ..gamma..-pyrone, was isolated in the pure state and its molecular structure is described in detail. (HLW)

  13. Superconducting tunneling with the tunneling Hamiltonian. II. Subgap harmonic structure

    International Nuclear Information System (INIS)

    Arnold, G.B.

    1987-01-01

    The theory of superconducting tunneling without the tunneling Hamiltonian is extended to treat superconductor/insulator/superconductor junctions in which the transmission coefficient of the insulating barrier approaches unity. The solution for the current in such junctions is obtained by solving the problem of a particle hopping in a one-dimensional lattice of sites, with forward and reverse transfer integrals that depend on the site. The results are applied to the problem of subgap harmonic structure in superconducting tunneling. The time-dependent current at finite voltage through a junction exhibiting subgap structure is found to have terms that oscillate at all integer multiples of the Josephson frequency, n(2eV/h). The amplitudes of these new, and as yet unmeasured, ac current contributions as a function of voltage are predicted

  14. Structure of dichloro(4-hydroxy-L-proline)cadmium(II)

    Energy Technology Data Exchange (ETDEWEB)

    Yukawa, Yasuhiko; Inomata, Yoshie; Takeuchi, Toshio [Jochi Univ., Tokyo (Japan). Faculty of Science and Technology; Shimoi, Mamoru; Ouchi, Akira

    1982-10-01

    An X-ray diffraction study of the title complex has been carried out. The crystal is monoclinic, with the space group P2/sub 1/; Z = 2; a = 8.196(4), b = 7.275(3), c = 7.740(4) A, beta = 103.73(4)/sup 0/. Full-matrix least-squares refinements have led to the final R value of 0.030. The structure consists of one-demensional polymers bridged by chlorine atoms and a carboxyl group. Four chlorine atoms coordinate to a cadmium atom and form a square plane. The planes extend in the direction of the b axis like an infinite folding screen, sharing opposite edges. From the trough positions in the zigzag structure, the carboxyl oxygen atoms of 4-hydroxy-L-proline coordinate forkedly to two cadmium atoms. The ligand is a switter ion in the complex.

  15. Synthesis and structural characterization of nickel(II), cobalt(II), Zinc(II), manganese(II), cadmium(II) and uranium(VI) complexes of α-oximinoacetoacet-o/p-anisidide thiosemicarbazone

    International Nuclear Information System (INIS)

    Patel, P.S.; Patel, M.M.; Ray, R.M.

    1993-01-01

    A few metal complexes of α-oximinoacetoacet-o/p-anisidide thiosemicarbazones (OAOATS)/(OAPATS) with Ni(II), Co(II), Zn(II), Mn(II), Hg(II), Cd(II) and UO 2 (II) have been prepared and characterized by elemental analyses, conductivity, differential scanning calorimetry study, thermogravimetric analyses and infrared and electronic spectral measurements in conjunction with magnetic susceptibility measurements at room temperature. They have also been tested for their antimicrobial activities. (author). 24 refs., 2 tabs

  16. Mini ion trap mass spectrometer

    Science.gov (United States)

    Dietrich, D.D.; Keville, R.F.

    1995-09-19

    An ion trap is described which operates in the regime between research ion traps which can detect ions with a mass resolution of better than 1:10{sup 9} and commercial mass spectrometers requiring 10{sup 4} ions with resolutions of a few hundred. The power consumption is kept to a minimum by the use of permanent magnets and a novel electron gun design. By Fourier analyzing the ion cyclotron resonance signals induced in the trap electrodes, a complete mass spectra in a single combined structure can be detected. An attribute of the ion trap mass spectrometer is that overall system size is drastically reduced due to combining a unique electron source and mass analyzer/detector in a single device. This enables portable low power mass spectrometers for the detection of environmental pollutants or illicit substances, as well as sensors for on board diagnostics to monitor engine performance or for active feedback in any process involving exhausting waste products. 10 figs.

  17. Solvation structure determination of nickel(II) ion in six nitriles using extended X-ray absorption fine structure spectroscopy

    International Nuclear Information System (INIS)

    Inada, Yasuhiro; Funahashi, Shigenobu

    1997-01-01

    The solvation structures of the nickel(II) ion in six nitriles have been determined using X-ray absorption fine structure spectroscopy. The coordination number and the Ni-N bond length are 6 and 206.9 ± 0.6 pm in acetonitrile, 5.9 ± 0.2 and 206.9 ± 0.6 pm in propionitrile, 6.0 ± 0.2 and 206.8 ± 0.6 pm in butyronitrile, 6.0 ± 0.2 and 206.8 ± 0.6 pm in isobutyronitrile, 6.0 ± 0.2 and 206.8 ± 0.6 pm in valeronitrile, and 6.0 ± 0.2 and 206.5 ± 0.7 pm in benzonitrile, respectively. The structure parameters around the nickel(II) ion in all the nitriles are not affected by the bulkiness of the nitrile molecules. On the basis of the obtained structure parameters, we have discussed the structural characteristics around the nickel(II) ion with nitrogen and oxygen donor solvents and the reaction mechanisms for nitrile exchange on the nickel(II) ion. (author)

  18. Structure of odd-A Pm nuclei (II)

    International Nuclear Information System (INIS)

    Piiparinen, M.; Kortelahti, M.; Pakkanen, A.; Komppa, T.; Komu, R.

    1977-12-01

    The level structures of 141 Pm and 145 Pm were studied by methods of in-beam γ-ray and electron spectroscopy using the reactions 142 Nd(p,2n) 141 Pm, 141 Pr( 3 He,3n) 141 Pm and 146 Nd(p,2n) 145 Pm. Nineteen new levels with spins up to (19/2) were observed in 141 Pm and twenty-two new levels with spins up to 15/2 in 145 Pm. In both nuclei, a group of positive-parity levels have been identified which can be interpreted as members of multiplets of d 5 / 2 and g 7 / 2 protons coupled to the quadrupole vibrations of the core. Transition probabilities of the decay modes of isomeric h 11 / 2 states have been determined. (author)

  19. Template Syntheses, Crystal Structures and Supramolecular Assembly of Hexaaza Macrocyclic Copper(II) Complexes

    International Nuclear Information System (INIS)

    Kim, Taehyung; Kim, Ju Chang; Lough, Alan J.

    2013-01-01

    Two new hexaaza macrocyclic copper(II) complexes were prepared by a template method and structurally characterized. In the solid state, they were self-assembled by intermolecular interactions to form the corresponding supramolecules 1 and 2, respectively. In the structure of 1, the copper(II) macrocycles are bridged by a tp ligand to form a macrocyclic copper(II) dimer. The dimer extends its structure by intermolecular forces such as hydrogen bonds and C-H···π interactions, resulting in the formation of a double stranded 1D supramolecule. In 2, the basic structure is a monomeric copper(II) macrocycle with deprotonated imidazole pendants. An undulated 1D hydrogen bonded array is achieved through hydrogen bonds between imidazole pendants and secondary amines, where the imidazole pendants act as a hydrogen bond acceptor. The 1D hydrogen bonded supramolecular chain is supported by C-H···π interactions between the methyl groups of acetonitrile ligands and imidazole pendants of the copper(II) macrocycles. In both complexes, the introduction of imidazoles to the macrocycle as a pendant plays an important role for the formation of supramolecules, where they act as intermolecular hydrogen bond donors and/or acceptors, C-H···π and π-π interactions

  20. Synthesis, crystal structure, spectroscopic characterization and nonlinear optical properties of Co(II)- picolinate complex

    Energy Technology Data Exchange (ETDEWEB)

    Tamer, Ömer, E-mail: omertamer@sakarya.edu.tr; Avcı, Davut; Atalay, Yusuf

    2015-11-15

    A cobalt(II) complex of picolinate was synthesized, and its structure was fully characterized by the applying of X-ray diffraction method as well as FT-IR, FT-Raman and UV–vis spectroscopies. In order to both support the experimental results and convert study to more advanced level, density functional theory calculations were performed by using B3LYP level. Single crystal X-ray structural analysis shows that cobalt(II) ion was located to the center of distorted octahedral geometry. The C=O, C=C and C=N stretching vibrations were found as highly active and strong peaks, inducing the molecular charge transfer within Co(II) complex. The small energy gap between frontier molecular orbital energies was another indicator of molecular charge transfer interactions within Co(II) complex. The nonlinear optical properties of Co(II) complex were investigated at DFT/B3LYP level, and the hypepolarizability parameter was found to be decreased due to the presence of inversion symmetry. The natural bond orbital (NBO) analysis was performed to investigate molecular stability, hyperconjugative interactions, intramolecular charge transfer (ICT) and bond strength for Co(II) complex. Finally, molecular electrostatic potential (MEP) and spin density distributions for Co(II) complex were evaluated. - Highlights: • Co(II) complex of picolinate was prepared. • Its FT-IR, FT-Raman and UV–vis spectra were measured. • DFT calculations were performed to support experimental results. • Small HOMO-LUMO energy gap is an indicator of molecular charge transfer. • Spin density localized on Co(II) as well as O and N atoms.

  1. Synthesis and formation process of SrSO{sub 4}:Sm{sup 3+} phosphors with hierarchical structures and its electron trapping luminescence properties

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Jiayue, E-mail: jiayue_sun@126.com; Sun, Guangchao; Xue, Bing; Cui, Dianpeng

    2013-10-15

    Highlights: •SrSO{sub 4} flower-like structures were synthesized by a aqueous solution route. •The as-prepared SrSO{sub 4} crystals have high crystalline. •The flower-like structures are composed of well aligned microtablets. •SrSO{sub 4} nuclei spontaneous attach by an “oriented attachment” process. •The SrSO{sub 4} crystals have excellent electron trapping luminescence properties. -- Abstract: Novel three-dimensional (3D) flower-like Strontium sulfate (SrSO{sub 4}) microstructures with hierarchical architecture were successfully fabricated by using Sr(NO{sub 3}){sub 2} react with Na{sub 2}SO{sub 4} aqueous solution under ambient conditions at room temperature. The SrSO{sub 4} flower-like microcrystals have a uniform diameter of about 10 μm, which are composed of numerous well-aligned single tablet-like SrSO{sub 4} crystals oriented radially to their center. The growth mechanism of the flower-like hierarchical celestine particles is discussed to obtain a better understanding on their formation process. XRD patterns confirm the single crystal phase of SrSO{sub 4}. In the photoluminescence property investigations of SrSO{sub 4}:Sm{sup 3+}, narrow bands observed are well identified with the electronic transition configurations of Sm{sup 3+}. The temperature-dependent photoluminescence spectra show that the temperature of maximum emission intensity is 25 °C. The thermal stability and electron trapping luminescence properties were also characterized.

  2. Origin and structures of solar eruptions II: Magnetic modeling

    Science.gov (United States)

    Guo, Yang; Cheng, Xin; Ding, MingDe

    2017-07-01

    The topology and dynamics of the three-dimensional magnetic field in the solar atmosphere govern various solar eruptive phenomena and activities, such as flares, coronal mass ejections, and filaments/prominences. We have to observe and model the vector magnetic field to understand the structures and physical mechanisms of these solar activities. Vector magnetic fields on the photosphere are routinely observed via the polarized light, and inferred with the inversion of Stokes profiles. To analyze these vector magnetic fields, we need first to remove the 180° ambiguity of the transverse components and correct the projection effect. Then, the vector magnetic field can be served as the boundary conditions for a force-free field modeling after a proper preprocessing. The photospheric velocity field can also be derived from a time sequence of vector magnetic fields. Three-dimensional magnetic field could be derived and studied with theoretical force-free field models, numerical nonlinear force-free field models, magnetohydrostatic models, and magnetohydrodynamic models. Magnetic energy can be computed with three-dimensional magnetic field models or a time series of vector magnetic field. The magnetic topology is analyzed by pinpointing the positions of magnetic null points, bald patches, and quasi-separatrix layers. As a well conserved physical quantity, magnetic helicity can be computed with various methods, such as the finite volume method, discrete flux tube method, and helicity flux integration method. This quantity serves as a promising parameter characterizing the activity level of solar active regions.

  3. M(II)-dipyridylamide-based coordination frameworks (M=Mn, Co, Ni): Structural transformation

    Energy Technology Data Exchange (ETDEWEB)

    Tzeng, Biing-Chiau; Selvam, TamilSelvi; Tsai, Miao-Hsin

    2016-11-15

    A series of 1-D double-zigzag (([M(papx){sub 2}(H{sub 2}O){sub 2}](ClO{sub 4}){sub 2}){sub n}; M=Mn, x=s (1), x=o (3); M=Co, x=s (4), x=o (5); M=Ni, x=s (6), x=o (7)) and 2-D polyrotaxane ([Mn(paps){sub 2}(ClO{sub 4}){sub 2}]{sub n} (2)) frameworks were synthesized by reactions of M(ClO{sub 4}){sub 2} (M=Mn, Co, and Ni) with papx (paps, N,N’-bis(pyridylcarbonyl)-4,4’-diaminodiphenylthioether; papo, N,N’-bis(pyridylcarbonyl)-4,4’-diaminodiphenyl ether), which have been isolated and structurally characterized by X-ray diffraction. Based on powder X-ray diffraction (PXRD) experiments, heating the double-zigzag frameworks underwent structural transformation to give the respective polyrotaxane ones. Moreover, grinding the solid samples of the respective polyrotaxanes in the presence of moisture also resulted in the total conversion to the original double-zigzag frameworks. In this study, we have successfully extended studies to Mn{sup II}, Co{sup II}, and Ni{sup II} frameworks from the previous Zn{sup II}, Cd{sup II}, and Cu{sup II} ones, and interestingly such structural transformation is able to be proven experimentally by powder and single-crystal X-ray diffraction studies as well. - Graphical abstract: 1-D double-zigzag and 2-D polyrotaxane frameworks of M(II)-papx (x=s, o; M=Mn, Co, Ni) frameworks can be interconverted by heating and grinding in the presence of moiture, and such structural transformation has be proven experimentally by powder and single-crystal X-ray diffraction studies.

  4. Structure and Function of Cu(I)- and Zn(II)-ATPases

    DEFF Research Database (Denmark)

    Sitsel, Oleg; Grønberg, Christina; Autzen, Henriette Elisabeth

    2015-01-01

    Copper and zinc are micronutrients essential for the function of many enzymes while also being toxic at elevated concentrations. Cu(I)- and Zn(II)-transporting P-type ATPases of subclass 1B are of key importance for the homeostasis of these transition metals, allowing ion transport across cellular...... membranes at the expense of ATP. Recent biochemical studies and crystal structures have significantly improved our understanding of the transport mechanisms of these proteins, but many details about their structure and function remain elusive. Here we compare the Cu(I)- and Zn(II)-ATPases, scrutinizing...

  5. Novel light trapping scheme for thin crystalline cells utilizing deep structures on both wafer sides [solar cells

    DEFF Research Database (Denmark)

    Jørgensen, Anders Michael; Clausen, Thomas; Leistiko, Otto

    1998-01-01

    62 times the average thickness. The structure consists of deep (-200 μm) inverted pyramids on the front side and deep (-200 μm) truncated pyramids with eight sides on the back. The structure is realized in crystalline silicon by wet chemical etching using potassium hydroxide (KOH) and isopropanol...

  6. Quark approach to Santilli's conjecture on hadronic structure - II

    International Nuclear Information System (INIS)

    Animalu, A.O.E.

    1982-08-01

    In this paper, we continue an earlier investigation of an exactly soluble relativistic Bohr-type model of the internal structure of the proton (three-quark baryon system) and the pion (quark-antiquark meson system), based on a realization of Santilli's conjecture that the hadronic constituents are extended (non-pointlike) objects. The model is abstracted from an expansion of a Yukawa-type potential between the valence quarks and a massive core, in which the meson or gluon exchange term has the effect of reducing the effective Bohr radius for binding to a value less than the radius of the strong charge sphere (or Compton wavelength) of each constituent, so that appreciable overlap of charge volumes occurs, to within a typical distance of order 0.25F or 1/(800 MeV) in qqq-system, and order 1/(1200 MeV) in qq-bar-system, which are comparable to gluon masses, msub(G) approx.= 800 to 1200 MeV, required by the lattice QCD and the MIT Bag Model. Based on the assumptions that the ground state of the proton has 1s 2 2s valence quark configuration, the non-strange quark mass is msub(p)/3, and the dimensionless strong coupling constant of the Yukawa-type potential is g 2 =1, the mass of the proton core is determined self-consistently to be 2470 MeV, exactly balancing the quark binding energy so that the valence quarks appear free. The model correctly predicts the masses of the well-known resonant states of the proton with Jsup(P)=1/2 + as excited states associated with the configuration 1s2s 2 and predicts an upper bound (spectroscopic limit) for the mass of the excited states of the proton in ns 2 ms configuration, as n→infinity and m→infinity, to be 3409 MeV. Based on a generalization of the model to qq-bar-systems, an upper bound (spectroscopic limit) for the mass of qq-bar in ns 2 configuration, as n→infinity, is found to be 3096 MeV, which is the mass of the J/psi-meson. The relation of the model to violation of time-reversal invariance (T-symmetry) by non

  7. Syntheses, structures, and properties of imidazolate-bridged Cu(II)-Cu(II) and Cu(II)-Zn(II) dinuclear complexes of a single macrocyclic ligand with two hydroxyethyl pendants.

    Science.gov (United States)

    Li, Dongfeng; Li, Shuan; Yang, Dexi; Yu, Jiuhong; Huang, Jin; Li, Yizhi; Tang, Wenxia

    2003-09-22

    The imidazolate-bridged homodinuclear Cu(II)-Cu(II) complex, [(CuimCu)L]ClO(4).0.5H(2)O (1), and heterodinuclear Cu(II)-Zn(II) complex, [(CuimZnL(-)(2H))(CuimZnL(-)(H))](ClO(4))(3) (2), of a single macrocyclic ligand with two hydroxyethyl pendants, L (L = 3,6,9,16,19,22-hexaaza-6,19-bis(2-hydroxyethyl)tricyclo[22,2,2,2(11,14)]triaconta-1,11,13,24,27,29-hexaene), have been synthesized as possible models for copper-zinc superoxide dismutase (Cu(2),Zn(2)-SOD). Their crystal structures analyzed by X-ray diffraction methods have shown that the structures of the two complexes are markedly different. Complex 1 crystallizes in the orthorhombic system, containing an imidazolate-bridged dicopper(II) [Cu-im-Cu](3+) core, in which the two copper(II) ions are pentacoordinated by virtue of an N4O environment with a Cu.Cu distance of 5.999(2) A, adopting the geometry of distorted trigonal bipyramid and tetragonal pyramid, respectively. Complex 2 crystallizes in the triclinic system, containing two similar Cu-im-Zn cores in the asymmetric unit, in which both the Cu(II) and Zn(II) ions are pentacoordinated in a distorted trigonal bipyramid geometry, with the Cu.Zn distance of 5.950(1)/5.939(1) A, respectively. Interestingly, the macrocyclic ligand with two arms possesses a chairlike (anti) conformation in complex 1, but a boatlike (syn) conformation in complex 2. Magnetic measurements and ESR spectroscopy of complex 1 have revealed the presence of an antiferromagnetic exchange interaction between the two Cu(II) ions. The ESR spectrum of the Cu(II)-Zn(II) heterodinuclear complex 2 displayed a typical signal for mononuclear trigonal bipyramidal Cu(II) complexes. From pH-dependent ESR and electronic spectroscopic studies, the imidazolate bridges in the two complexes have been found to be stable over broad pH ranges. The cyclic voltammograms of the two complexes have been investigated. Both of the two complexes can catalyze the dismutation of superoxide and show rather high activity.

  8. The structure of the local interstellar medium. VI. New Mg II, Fe II, and Mn II observations toward stars within 100 pc

    International Nuclear Information System (INIS)

    Malamut, Craig; Redfield, Seth; Linsky, Jeffrey L.; Wood, Brian E.; Ayres, Thomas R.

    2014-01-01

    We analyze high-resolution spectra obtained with the Space Telescope Imaging Spectrograph onboard the Hubble Space Telescope toward 34 nearby stars (≤100 pc) to record Mg II, Fe II, and Mn II absorption due to the local interstellar medium (LISM). Observations span the entire sky, probing previously unobserved regions of the LISM. The heavy ions studied in this survey produce narrow absorption features that facilitate the identification of multiple interstellar components. We detected one to six individual absorption components along any given sight line, and the number of absorbers roughly correlates with the pathlength. This high-resolution near-ultraviolet (NUV) spectroscopic survey was specifically designed for sight lines with existing far-UV (FUV) observations. The FUV spectra include many intrinsically broad absorption lines (i.e., of low atomic mass ions) and are often observed at medium resolution. The LISM NUV narrow-line absorption component structure presented here can be used to more accurately interpret the archival FUV observations. As an example of this synergy, we present a new analysis of the temperature and turbulence along the line of sight toward ε Ind. The new observations of LISM velocity structure are also critical in the interpretation of astrospheric absorption derived from fitting the saturated H I Lyα profile. As an example, we reanalyze the spectrum of λ And and find that this star likely does have an astrosphere. Two stars in the sample that have circumstellar disks (49 Cet and HD141569) show evidence for absorption due to disk gas. Finally, the substantially increased number of sight lines is used to test and refine the three-dimensional kinematic model of the LISM and search for previously unidentified clouds within the Local Bubble. We find that every prediction made by the Redfield and Linsky kinematic model of the LISM is confirmed by an observed component in the new lines of sight.

  9. Synthesis, structure and fluorescence properties of a novel 3D Sr(II) coordination polymer

    Science.gov (United States)

    Tan, Yu-Hui; Xu, Qing; Gu, Zhi-Feng; Gao, Ji-Xing; Wang, Bin; Liu, Yi; Yang, Chang-Shan; Tang, Yun-Zhi

    2016-09-01

    Solvothermal reaction of 2,2‧-bipyridine-5,5‧-dicarboxylic acid (H2bpdc) and SrCl2 affords a novel coordination polymer [Sr(Hbpdc)2]n1. X-ray structure determination shows that 1 exhibits a novel three-dimensional network. The unique Sr II cation sits on a two-fold axis and coordinated by four O-atom donors from four Hbptc- ligands and four N-atom donors from two Hbptc- ligands in distorted dodecahedral geometry. In 1 each Sr II cation connects to six different Hbptc- ligands and each Hbptc- ligand bridges three different Sr II cations which results in the formation of a three-dimensional polymeric structure. Corresponding to the free ligand, the fluorescent emission of complex 1 display remarkable "Einstain" shifts, which may be attributed to the coordination interaction of Sr atoms, thus reduce the rigidity of pyridyl rings.

  10. Crystal structure of CobK reveals strand-swapping between Rossmann-fold domains and molecular basis of the reduced precorrin product trap.

    Science.gov (United States)

    Gu, Shuang; Sushko, Oleksandr; Deery, Evelyne; Warren, Martin J; Pickersgill, Richard W

    2015-11-30

    CobK catalyzes the essential reduction of the precorrin ring in the cobalamin biosynthetic pathway. The crystal structure of CobK reveals that the enzyme, despite not having the signature sequence, comprises two Rossmann fold domains which bind coenzyme and substrate respectively. The two parallel β-sheets have swapped their last β-strands giving a novel sheet topology which is an interesting variation on the Rossmann-fold. The trapped ternary complex with coenzyme and product reveals five conserved basic residues that bind the carboxylates of the tetrapyrrole tightly anchoring the product. A loop, disordered in both the apoenzyme and holoenzyme structures, closes around the product further tightening binding. The structure is consistent with a mechanism involving protonation of C18 and pro-R hydride transfer from NADPH to C19 of precorrin-6A and reveals the interactions responsible for the specificity of CobK. The almost complete burial of the reduced precorrin product suggests a remarkable form of metabolite channeling where the next enzyme in the biosynthetic pathway triggers product release.

  11. Nonlinear Aerodynamic and Nonlinear Structures Interations (NANSI) Methodology for Ballute/Inflatable Aeroelasticity in Hypersonic Atmospheric Entry, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — ZONA proposes a phase II effort to fully develop a comprehensive methodology for aeroelastic predictions of the nonlinear aerodynamic/aerothermodynamic - structure...

  12. Flow structure formation in an ion-unmagnetized plasma: The HYPER-II experiments

    Science.gov (United States)

    Terasaka, K.; Tanaka, M. Y.; Yoshimura, S.; Aramaki, M.; Sakamoto, Y.; Kawazu, F.; Furuta, K.; Takatsuka, N.; Masuda, M.; Nakano, R.

    2015-01-01

    The HYPER-II device has been constructed in Kyushu University to investigate the flow structure formation in an ion-unmagnetized plasma, which is an intermediate state of plasma and consists of unmagnetized ions and magnetized electrons. High density plasmas are produced by electron cyclotron resonance heating, and the flow field structure in an inhomogeneous magnetic field is investigated with a directional Langmuir probe method and a laser-induced fluorescence method. The experimental setup has been completed and the diagnostic systems have been installed to start the experiments. A set of coaxial electrodes will be introduced to control the azimuthal plasma rotation, and the effect of plasma rotation to generation of rectilinear flow structure will be studied. The HYPER-II experiments will clarify the overall flow structure in the inhomogeneous magnetic field and contribute to understanding characteristic feature of the intermediate state of plasma.

  13. Trapped atoms along nanophotonic resonators

    Science.gov (United States)

    Fields, Brian; Kim, May; Chang, Tzu-Han; Hung, Chen-Lung

    2017-04-01

    Many-body systems subject to long-range interactions have remained a very challenging topic experimentally. Ultracold atoms trapped in extreme proximity to the surface of nanophotonic structures provides a dynamic system combining the strong atom-atom interactions mediated by guided mode photons with the exquisite control implemented with trapped atom systems. The hybrid system promises pair-wise tunability of long-range interactions between atomic pseudo spins, allowing studies of quantum magnetism extending far beyond nearest neighbor interactions. In this talk, we will discuss our current status developing high quality nanophotonic ring resonators, engineered on CMOS compatible optical chips with integrated nanostructures that, in combination with a side illuminating beam, can realize stable atom traps approximately 100nm above the surface. We will report on our progress towards loading arrays of cold atoms near the surface of these structures and studying atom-atom interaction mediated by photons with high cooperativity.

  14. Materials science in microelectronics II the effects of structure on properties in thin films

    CERN Document Server

    Machlin, Eugene

    2005-01-01

    The subject matter of thin-films - which play a key role in microelectronics - divides naturally into two headings: the processing / structure relationship, and the structure / properties relationship. Part II of 'Materials Science in Microelectronics' focuses on the latter of these relationships, examining the effect of structure on the following: Electrical properties Magnetic properties Optical properties Mechanical properties Mass transport properties Interface and junction properties Defects and properties Captures the importance of thin films to microelectronic development Examines the cause / effect relationship of structure on thin film properties.

  15. Effects of oxide traps, interface traps, and ''border traps'' on metal-oxide-semiconductor devices

    International Nuclear Information System (INIS)

    Fleetwood, D.M.; Winokur, P.S.; Reber, R.A. Jr.; Meisenheimer, T.L.; Schwank, J.R.; Shaneyfelt, M.R.; Riewe, L.C.

    1993-01-01

    We have identified several features of the 1/f noise and radiation response of metal-oxide-semiconductor (MOS) devices that are difficult to explain with standard defect models. To address this issue, and in response to ambiguities in the literature, we have developed a revised nomenclature for defects in MOS devices that clearly distinguishes the language used to describe the physical location of defects from that used to describe their electrical response. In this nomenclature, ''oxide traps'' are simply defects in the SiO 2 layer of the MOS structure, and ''interface traps'' are defects at the Si/SiO 2 interface. Nothing is presumed about how either type of defect communicates with the underlying Si. Electrically, ''fixed states'' are defined as trap levels that do not communicate with the Si on the time scale of the measurements, but ''switching states'' can exchange charge with the Si. Fixed states presumably are oxide traps in most types of measurements, but switching states can either be interface traps or near-interfacial oxide traps that can communicate with the Si, i.e., ''border traps'' [D. M. Fleetwood, IEEE Trans. Nucl. Sci. NS-39, 269 (1992)]. The effective density of border traps depends on the time scale and bias conditions of the measurements. We show the revised nomenclature can provide focus to discussions of the buildup and annealing of radiation-induced charge in non-radiation-hardened MOS transistors, and to changes in the 1/f noise of MOS devices through irradiation and elevated-temperature annealing

  16. PREREM: an interactive data preprocessing code for INREM II. Part I: user's manual. Part II: code structure

    Energy Technology Data Exchange (ETDEWEB)

    Ryan, M.T.; Fields, D.E.

    1981-05-01

    PREREM is an interactive computer code developed as a data preprocessor for the INREM-II (Killough, Dunning, and Pleasant, 1978a) internal dose program. PREREM is intended to provide easy access to current and self-consistent nuclear decay and radionuclide-specific metabolic data sets. Provision is made for revision of metabolic data, and the code is intended for both production and research applications. Documentation for the code is in two parts. Part I is a user's manual which emphasizes interpretation of program prompts and choice of user input. Part II stresses internal structure and flow of program control and is intended to assist the researcher who wishes to revise or modify the code or add to its capabilities. PREREM is written for execution on a Digital Equipment Corporation PDP-10 System and much of the code will require revision before it can be run on other machines. The source program length is 950 lines (116 blocks) and computer core required for execution is 212 K bytes. The user must also have sufficient file space for metabolic and S-factor data sets. Further, 64 100 K byte blocks of computer storage space are required for the nuclear decay data file. Computer storage space must also be available for any output files produced during the PREREM execution. 9 refs., 8 tabs.

  17. Lipids in the Structure of Photosystem I, Photosystem II and the Cytochrome b6f Complex

    NARCIS (Netherlands)

    Kern, Jan; Zouni, Athina; Guskov, Albert; Krauss, Norbert; Wada, Hajime; Murata, Norio

    2009-01-01

    This chapter describes the data accumulated in the last decade regarding the specific function of lipids in oxygenic photosynthesis, based on crystal structures of at least 3.0 Å resolution of the main photosynthetic membrane protein—pigment complexes, photosystem I, photosystem II and cytochrome

  18. Shrew trap efficiency

    DEFF Research Database (Denmark)

    Gambalemoke, Mbalitini; Mukinzi, Itoka; Amundala, Drazo

    2008-01-01

    We investigated the efficiency of four trap types (pitfall, Sherman LFA, Victor snap and Museum Special snap traps) to capture shrews. This experiment was conducted in five inter-riverine forest blocks in the region of Kisangani. The total trapping effort was 6,300, 9,240, 5,280 and 5,460 trap......, our results indicate that pitfall traps are the most efficient for capturing shrews: not only do they have a higher efficiency (yield), but the taxonomic diversity of shrews is also higher when pitfall traps are used....

  19. Crystal Structure of a Trapped Catalytic Intermediate Suggests that Forced Atomic Proximity Drives the Catalysis of mIPS

    OpenAIRE

    Neelon, Kelly; Roberts, Mary F.; Stec, Boguslaw

    2011-01-01

    1-L-myo-inositol-phosphate synthase (mIPS) catalyzes the first step of the unique, de novo pathway of inositol biosynthesis. However, details about the complex mIPS catalytic mechanism, which requires oxidation, enolization, intramolecular aldol cyclization, and reduction, are not fully known. To gain further insight into this mechanism, we determined the crystal structure of the wild-type mIPS from Archaeoglobus fulgidus at 1.7 Å, as well as the crystal structures of three active-site mutant...

  20. Bayesian Averaging over Many Dynamic Model Structures with Evidence on the Great Ratios and Liquidity Trap Risk

    NARCIS (Netherlands)

    R.W. Strachan (Rodney); H.K. van Dijk (Herman)

    2008-01-01

    textabstractA Bayesian model averaging procedure is presented that makes use of a finite mixture of many model structures within the class of vector autoregressive (VAR) processes. It is applied to two empirical issues. First, stability of the Great Ratios in U.S. macro-economic time series is

  1. Theoretical modeling of the electronic structure and exchange interactions in Cu(II)Pc

    Science.gov (United States)

    Wu, Wei; Fisher, A. J.; Harrison, N. M.; Wang, Hai; Wu, Zhenlin; Gardener, Jules; Heutz, Sandrine; Jones, Tim; Aeppli, Gabriel

    2012-12-01

    We calculate the electronic structure and exchange interactions in a copper(II)phthalocyanine (Cu(II)Pc) crystal as a one-dimensional molecular chain using hybrid exchange density functional theory (DFT). In addition, the intermolecular exchange interactions are also calculated in a molecular dimer using Green's function perturbation theory (GFPT) to illustrate the underlying physics. We find that the exchange interactions depend strongly on the stacking angle, but weakly on the sliding angle (defined in the text). The hybrid DFT calculations also provide an insight into the electronic structure of the Cu(II)Pc molecular chain and demonstrate that on-site electron correlations have a significant effect on the nature of the ground state, the band gap and magnetic excitations. The exchange interactions predicted by our DFT calculations and GFPT calculations agree qualitatively with the recent experimental results on newly found η-Cu(II)Pc and the previous results for the α- and β-phases. This work provides a reliable theoretical basis for the further application of Cu(II)Pc to molecular spintronics and organic-based quantum information processing.

  2. Correlation of reactivity with structural factors in a series of Fe(II) substituted cobalt ferrites

    International Nuclear Information System (INIS)

    Sileo, Elsa E.; Garcia Rodenas, Luis; Paiva-Santos, Carlos O.; Stephens, Peter W.; Morando, Pedro J.; Blesa, Miguel A.

    2006-01-01

    A series of powdered cobalt ferrites, Co x Fe 3- x O 4 with 0.66≤x II , were synthesized by a mild procedure, and their Fe and Co site occupancies and structural characteristics were explored using X-ray anomalous scattering and the Rietveld refinement method. The dissolution kinetics, measured in 0.1 M oxalic acid aqueous solution at 70 deg. C, indicate in all cases the operation of a contracting volume rate law. The specific rates increased with the Fe II content following approximately a second-order polynomial expression. This result suggests that the transfer of Fe III controls the dissolution rate, and that the leaching of a first layer of ions Co II and Fe II leaves exposed a surface enriched in slower dissolving octahedral Fe III ions. Within this model, inner vicinal lattice Fe II accelerates the rate of Fe III transfer via internal electron hopping. A chain mechanism, involving successive electron transfers, fits the data very well. - Graphical abstract: The electron exchange between octahedral Fe II and Fe III ions has important consequences on the specific dissolution rates. Display Omitted

  3. High Resolution Crystal Structures of Streptococcus pneumoniae Nicotinamidase with Trapped Intermediates Provide Insights into Catalytic Mechanism and Inhibition by Aldehydes∥,‡

    Science.gov (United States)

    French, Jarrod B.; Cen, Yana; Sauve, Anthony A.; Ealick, Steven E.

    2010-01-01

    Nicotinamidases are salvage enzymes that convert nicotinamide to nicotinic acid. These enzymes are essential for the recycling of nicotinamide into NAD+ in most prokaryotes, most single cell and multicellular eukaryotes, but not in mammals. The significance of these enzymes for nicotinamide salvage and for NAD+ homeostasis has increased interest in nicotinamidases as possible antibiotic targets. Nicotinamidases are also regulators of intracellular nicotinamide concentrations, thereby regulating signaling of downstream NAD+ consuming enzymes, such as the NAD+-dependent deacetylases (sirtuins). Here, we report several high resolution crystal structures of the nicotinamidase from Streptococcus pneumoniae (SpNic) in unliganded and ligand-bound forms. The structure of the C136S mutant in complex with nicotinamide provides details about substrate binding while a trapped nicotinoyl-thioester complexed with SpNic reveals the structure of the proposed thioester reaction intermediate. Examination of the active site of SpNic reveals several important features including a metal ion that coordinates the substrate and the catalytically relevant water molecule, and an oxyanion hole which both orients the substrate and offsets the negative charge that builds up during catalysis. Structures of this enzyme with bound nicotinaldehyde inhibitors elucidate the mechanism of inhibition and provide further details about the catalytic mechanism. In addition, we provide a biochemical analysis of the identity and role of the metal ion that orients the ligand in the active site and activates the water molecule responsible for hydrolysis of the substrate. These data provide structural evidence for several proposed reaction intermediates and allow for a more complete understanding of the catalytic mechanism of this enzyme. PMID:20853856

  4. High-resolution crystal structures of Streptococcus pneumoniae nicotinamidase with trapped intermediates provide insights into the catalytic mechanism and inhibition by aldehydes .

    Science.gov (United States)

    French, Jarrod B; Cen, Yana; Sauve, Anthony A; Ealick, Steven E

    2010-10-12

    Nicotinamidases are salvage enzymes that convert nicotinamide to nicotinic acid. These enzymes are essential for the recycling of nicotinamide into NAD(+) in most prokaryotes and most single-cell and multicellular eukaryotes, but not in mammals. The significance of these enzymes for nicotinamide salvage and for NAD(+) homeostasis has stimulated interest in nicotinamidases as possible antibiotic targets. Nicotinamidases are also regulators of intracellular nicotinamide concentrations, thereby regulating signaling of downstream NAD(+)-consuming enzymes, such as the NAD(+)-dependent deacetylases (sirtuins). Here, we report several high-resolution crystal structures of the nicotinamidase from Streptococcus pneumoniae (SpNic) in unliganded and ligand-bound forms. The structure of the C136S mutant in complex with nicotinamide provides details about substrate binding, while a trapped nicotinoyl thioester in a complex with SpNic reveals the structure of the proposed thioester reaction intermediate. Examination of the active site of SpNic reveals several important features, including a metal ion that coordinates the substrate and the catalytically relevant water molecule and an oxyanion hole that both orients the substrate and offsets the negative charge that builds up during catalysis. Structures of this enzyme with bound nicotinaldehyde inhibitors elucidate the mechanism of inhibition and provide further details about the catalytic mechanism. In addition, we provide a biochemical analysis of the identity and role of the metal ion that orients the ligand in the active site and activates the water molecule responsible for hydrolysis of the substrate. These data provide structural evidence of several proposed reaction intermediates and allow for a more complete understanding of the catalytic mechanism of this enzyme.

  5. High-Resolution Crystal Structures of Streptococcus pneumoniae Nicotinamidase with Trapped Intermediates Provide Insights into the Catalytic Mechanism and Inhibition by Aldehydes

    Energy Technology Data Exchange (ETDEWEB)

    French, Jarrod B.; Cen, Yana; Sauve, Anthony A.; Ealick, Steven E. (Cornell); (Weill-Med)

    2010-11-11

    Nicotinamidases are salvage enzymes that convert nicotinamide to nicotinic acid. These enzymes are essential for the recycling of nicotinamide into NAD{sup +} in most prokaryotes and most single-cell and multicellular eukaryotes, but not in mammals. The significance of these enzymes for nicotinamide salvage and for NAD{sup +} homeostasis has stimulated interest in nicotinamidases as possible antibiotic targets. Nicotinamidases are also regulators of intracellular nicotinamide concentrations, thereby regulating signaling of downstream NAD{sup +}-consuming enzymes, such as the NAD{sup +}-dependent deacetylases (sirtuins). Here, we report several high-resolution crystal structures of the nicotinamidase from Streptococcus pneumoniae (SpNic) in unliganded and ligand-bound forms. The structure of the C136S mutant in complex with nicotinamide provides details about substrate binding, while a trapped nicotinoyl thioester in a complex with SpNic reveals the structure of the proposed thioester reaction intermediate. Examination of the active site of SpNic reveals several important features, including a metal ion that coordinates the substrate and the catalytically relevant water molecule and an oxyanion hole that both orients the substrate and offsets the negative charge that builds up during catalysis. Structures of this enzyme with bound nicotinaldehyde inhibitors elucidate the mechanism of inhibition and provide further details about the catalytic mechanism. In addition, we provide a biochemical analysis of the identity and role of the metal ion that orients the ligand in the active site and activates the water molecule responsible for hydrolysis of the substrate. These data provide structural evidence of several proposed reaction intermediates and allow for a more complete understanding of the catalytic mechanism of this enzyme.

  6. Preliminary Guideline for the High Temperature Structure Integrity Assessment Procedure Part II. High Temperature Structural Integrity Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae Han; Kim, J. B.; Lee, H. Y.; Park, C. G.; Joo, Y. S.; Koo, G. H.; Kim, S. H

    2007-02-15

    A high temperature structural integrity assessment belongs to the Part II of a whole preliminary guideline for the high temperature structure. The main contents of this guideline are the evaluation procedures of the creep-fatigue crack initiation and growth in high temperature condition, the high temperature LBB evaluation procedure, and the inelastic evaluations of the welded joints in SFR structures. The methodologies for the proper inelastic analysis of an SFR structures in high temperatures are explained and the guidelines of inelastic analysis options using ANSYS and ABAQUS are suggested. In addition, user guidelines for the developed NONSTA code are included. This guidelines need to be continuously revised to improve the applicability to the design and analysis of the SFR structures.

  7. The investigation of structure, chemical composition, hydrogen isotope trapping and release processes in deposition layers on surfaces exposed to DIII-D divertor plasma

    International Nuclear Information System (INIS)

    Buzhinskij, O.I.; Opimach, I.V.; Barsuk, V.A.; Arkhipov, I.I.; Whyte, D.; Wampler, W.R.

    1998-05-01

    The exposure of ATG graphite sample to DIII-D divertor plasma was provided by the DiMES (Divertor Material Evaluation System) mechanism. The graphite sample arranged to receive the parallel heat flux on a small region of the surface was exposed to 600ms of outer strike point plasma. The sample was constructed to collect the eroded material directed downward into a trapping zone onto s Si disk collector. The average heat flux onto the graphite sample during the exposure was about 200W/cm 2 , and the parallel heat flux was about 10 KW/cm 2 . After the exposure the graphite sample and Si collector disk were analyzed using SEM, NRA, RBS, Auger spectroscopy. IR and Raman spectroscopy. The thermal desorption was studied also. The deposited coating on graphite sample is amorphous carbon layer. Just upstream of the high heat flux zone the redeposition layer has a globular structure. The deposition layer on Si disk is composed also from carbon but has a diamond-like structure. The areal density of C and D in the deposited layer on Si disk varied in poloidal and toroidal directions. The maximum D/C areal density ratio is about 0.23, maximum carbon density is about 3.8 x 10 18 cm -2 , maximum D area density is about 3 x 10 17 cm 2 . The thermal desorption spectrum had a peak at 1,250K

  8. St. Croix trap study

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data set contains detailed information about the catch from 600 trap stations around St. Croix. Data fields include species caught, size data, trap location...

  9. A magnetic particle micro-trap for large trapping surfaces

    KAUST Repository

    Gooneratne, Chinthaka P.

    2012-01-08

    Manipulation of micron-size magnetic particles of the superparamagnetic type contributes significantly in many applications like controlling the antibody/antigen binding process in immunoassays. Specifically, more target biomolecules can be attached/tagged and analyzed since the three dimensional structure of the magnetic particles increases the surface to volume ratio. Additionally, such biomolecular-tagged magnetic particles can be easily manipulated by an external magnetic field due to their superparamagnetic behavior. Therefore, magnetic particle- based immunoassays are extensively applied in micro-flow cytometry. The design of a square-loop micro-trap as a magnetic particle manipulator as well as numerical and experimental analysis is presented. Experimental results showed that the micro-trap could successfully trap and concentrate magnetic particles from a large to a small area with a high spatial range.

  10. A magnetic particle micro-trap for large trapping surfaces

    KAUST Repository

    Gooneratne, Chinthaka P.; Liang, Cai; Giouroudi, Ioanna; Kosel, Jü rgen

    2012-01-01

    Manipulation of micron-size magnetic particles of the superparamagnetic type contributes significantly in many applications like controlling the antibody/antigen binding process in immunoassays. Specifically, more target biomolecules can be attached/tagged and analyzed since the three dimensional structure of the magnetic particles increases the surface to volume ratio. Additionally, such biomolecular-tagged magnetic particles can be easily manipulated by an external magnetic field due to their superparamagnetic behavior. Therefore, magnetic particle- based immunoassays are extensively applied in micro-flow cytometry. The design of a square-loop micro-trap as a magnetic particle manipulator as well as numerical and experimental analysis is presented. Experimental results showed that the micro-trap could successfully trap and concentrate magnetic particles from a large to a small area with a high spatial range.

  11. Thermal-structural response of EBR-II major components under reactor operational transients

    International Nuclear Information System (INIS)

    Chang, L.K.; Lee, M.J.

    1983-01-01

    Until recently, the LMFBR safety research has been focused primarily on severe but highly unlikely accident, such as hypothetical-core-disruptive accidents (HCDA's), and not enough attention has been given to accident prevention, which is less severe but more likely sequence. The objective of the EBR-II operational reliability testing (ORT) is to demonstrate that the reactor can be designed and operated to prevent accident. A series of mild duty cycles and overpower transients were designed for accident prevention tests. An assessment of the EBR-II major plant components has been performed to assure structural integrity of the reactor plant for the ORT program. In this paper, the thermal-structural response and structural evaluation of the reactor vessel, the reactor-vessel cover, the intermediate heat exchanger (IHX) and the superheater are presented

  12. Synthesis and crystal structure of two lead (II) complexes with 1,10-phenanthroline ligand

    International Nuclear Information System (INIS)

    Olivera, Fiorella L.; Santillan, Guillermo A.

    2012-01-01

    Two coordination complexes have been synthesized by the reaction of lead nitrate (II) with 1,10-phenanthroline in methanol/water. The crystals of these complexes were obtained by using the diffusion method and structurally characterized by X-ray single crystal diffraction. Both complexes crystallized in the monoclinic space group P2 1 /c. The analysis by crystal X-ray diffraction reveals that in both complexes the coordination around the lead (II) ion is a distorted octahedral structure where the ion is bonded to the heterocyclic nitrogen atoms of chelating ligand 1,10-phenanthroline, three oxygen atoms of three nitrate groups and one oxygen from the water molecule. The difference between the complexes lies in the way of nitrate ion in presence of carboxylic acid aromatics. In addition, the crystal structure of complexes can be regarded as a 3D coordination polymer through Pb-O weak interactions, hydrogen bonds and π-π stacking interactions. (author).

  13. Nonlinear soil-structure interaction analysis of SIMQUAKE II. Final report

    International Nuclear Information System (INIS)

    Vaughan, D.K.; Isenberg, J.

    1982-04-01

    This report describes an analytic method for modeling of soil-structure interaction (SSI) for nuclear power plants in earthquakes and discusses its application to SSI analyses of SIMQUAKE II. The method is general and can be used to simulate a three-dimensional structural geometry, nonlinear site characteristics and arbitrary input ground shaking. The analytic approach uses the soil island concept to reduce SSI models to manageable size and cost. Nonlinear constitutive behavior of the soil is represented by the nonlinear, kinematic cap model. In addition, a debonding-rebonding soil-structure interface model is utilized to represent nonlinear effects which singificantly alter structural response in the SIMQUAKE tests. STEALTH, an explicit finite difference code, is used to perform the dynamic, soil-structure interaction analyses. Several two-dimensional posttest SSI analyses of model containment structures in SIMQUAKE II are performed and results compared with measured data. These analyses qualify the analytic method. They also show the importance of including debonding-rebonding at the soil-structure interface. Sensitivity of structural response to compaction characteristics of backfill material is indicated

  14. Angular trap for macroparticles

    International Nuclear Information System (INIS)

    Aksyonov, D.S.

    2013-01-01

    Properties of angular macroparticle traps were investigated in this work. These properties are required to design vacuum arc plasma filters. The correlation between trap geometry parameters and its ability to absorb macroparticles were found. Calculations allow one to predict the behaviour of filtering abilities of separators which contain such traps in their design. Recommendations regarding the use of angular traps in filters of different builds are given.

  15. Synthesis and Crystal Structures of Luminescent Mononuclear Ni(ii and Cd(ii Complexes with 1,10-phenanthroline

    Directory of Open Access Journals (Sweden)

    Ecaterina Tocana

    2017-12-01

    Full Text Available New supramolecular systems of Ni(II and Cd(II with 1,10-phenanthroline constructed by non-covalent interactions have been synthesized and characterized by single-crystal X-ray diffractometry. The smaller nickel(II ion forms a cis complex with outer-sphere perchlorates, while the cadmium(II ion forms a trans complex involving inner-sphere perchlorates. Both compoundsrevealintraligand-basedluminescentproperties.

  16. Synthesis, molecular structure, biological properties and molecular docking studies on Mn(II), Co(II) and Zn(II) complexes containing bipyridine-azide ligands.

    Science.gov (United States)

    Thamilarasan, Vijayan; Jayamani, Arumugam; Sengottuvelan, Nallathambi

    2015-01-07

    Metal complexes of the type Mn(bpy)2(N3)2 (1), Co(bpy)2(N3)2·3H2O (2) and Zn2(bpy)2(N3)4 (3) (Where bpy = 2,2-bipyridine) have been synthesized and characterized by elemental analysis and spectral (FT-IR, UV-vis) studies. The structure of complexes (1-3) have been determined by single crystal X-ray diffraction studies and the configuration of ligand-coordinated metal(II) ion was well described as distorted octahedral coordination geometry for Mn(II), Co(II) and distorted square pyramidal geometry for Zn(II) complexes. DNA binding interaction of these complexes (1-3) were investigated by UV-vis absorption, fluorescence circular dichroism spectral and molecular docking studies. The intrinsic binding constants Kb of complexes 1, 2 and 3 with CT-DNA obtained from UV-vis absorption studies were 8.37 × 10(4), 2.23 × 10(5) and 5.52 × 10(4) M(-1) respectively. The results indicated that the three complexes are able to bind to DNA with different binding affinity, in the order 2 > 1 > 3. Complexes (1-3) exhibit a good binding propensity to bovine serum albumin (BSA) proteins having relatively high binding constant values. Gel electrophoresis assay demonstrated the ability of the complexes 1-3 promote the cleavage ability of the pBR322 plasmid DNA in the presence of the reducing agent 3-mercaptopropionic acid (MPA) but with different cleavage mechanisms: the complex 3 cleaves DNA via hydrolytic pathway (T4 DNA ligase assay), while the DNA cleavage by complexes 1 and 2 follows oxidative pathway. The chemical nuclease activity follows the order: 2 > 1 > 3. The effects of various activators were also investigated and the nuclease activity efficacy followed the order MPA > GSH > H2O2 > Asc. The cytotoxicity studies of complexes 1-3 were tested in vitro on breast cancer cell line (MCF-7) and they found to be active. Copyright © 2014. Published by Elsevier Masson SAS.

  17. Analysis of a Mark II containment structure for hydrodynamic loads in suppression pool

    International Nuclear Information System (INIS)

    Bedrosian, B.

    1978-01-01

    During pressure-relief modes of BWR plant operation forcing signals are introduced into the suppression pool at discrete locations: exit nozzles of SRV discharge pipes (quenchers or ramsheads). These forcing signals are transmitted through the water of the suppression pool and, after reaching the pool boundaries, act as loadings on the containment structure wetted perimeter. The response of the containment structure is influenced by the presence of water as it interacts with the structure during application of the load. An adequate analysis must account for fluid-structure interaction (FSI) effects. This paper presents an exact formulation for solving the problem. FSI effects may become significant for a given geometry if the time history of loading and the dynamic properties of the coupled fluid-structure system satisfy a defined (system related) relationship. Results of analyses and parametric/sensitivity studies performed for the steel containment structure of an 1100 Mwe BWR nuclear plant of Mark II configuration are presented. (Author)

  18. Temperature and emission-line structure at the edges of H II regions

    International Nuclear Information System (INIS)

    Mallik, D.C.V.

    1975-01-01

    Models of ionization fronts located at the edges of expanding H ii regions are presented. These fronts are of the weak D-type and are preceded by shocks in the H i clouds. Since the energy input time is smaller than the cooling time, the gas is found to heat up to a high temperature immediately following ionization. At the trailing edge of the front, the temperature decreases and the ionized gas merges with the main bulk of the nebula where the physical processes are in equilibrium. The emission in O ii and N ii lines is greatly enhanced because of the high temperature at the front. The emission in these and other important lines is calculated and compared with Hβ. Effects of different velocities of flow, of different exciting stars, and of different gas densities on the structure of the fronts are also investigated

  19. Synthesis, structure, and magnetic properties of two 1-D helical coordination polymeric Cu(II) complexes

    Science.gov (United States)

    Bian, He-Dong; Yang, Xiao-E.; Yu, Qing; Chen, Zi-Lu; Liang, Hong; Yan, Shi-Ping; Liao, Dai-Zheng

    2008-01-01

    Two helical coordination polymeric copper(II) complexes bearing amino acid Schiff bases HL or HL', which are condensed from 2-hydroxy-1-naphthaldehyde with 2-aminobenzoic acid or L-valine, respectively, have been prepared and characterised by X-ray crystallography. In [CuL] n ( 1) the copper(II) atoms are bridged by syn- anti carboxylate groups giving infinite 1-D right-handed helical chains which are further connected by weak C-H⋯Cu interactions to build a 2-D network. While in [CuL'] n ( 2) the carboxylate group acts as a rare monatomic bridge to connect the adjacent copper(II) atoms leading to the formation of a left-handed helical chain. Magnetic susceptibility measurements indicate that 1 exhibits weak ferromagnetic interactions whereas an antiferromagnetic coupling is established for 2. The magnetic behavior can be satisfactorily explained on the basis of the structural data.

  20. Effect of trap position on the efficiency of trapping in treelike scale-free networks

    International Nuclear Information System (INIS)

    Zhang Zhongzhi; Lin Yuan; Ma Youjun

    2011-01-01

    The conventional wisdom is that the role and impact of nodes on dynamical processes in scale-free networks are not homogenous, because of the presence of highly connected nodes at the tail of their power-law degree distribution. In this paper, we explore the influence of different nodes as traps on the trapping efficiency of the trapping problem taking place on scale-free networks. To this end, we study in detail the trapping problem in two families of deterministically growing scale-free networks with treelike structure: one family is non-fractal, the other is fractal. In the first part of this work, we attack a special case of random walks on the two network families with a perfect trap located at a hub, i.e. node with the highest degree. The second study addresses the case with trap distributed uniformly over all nodes in the networks. For these two cases, we compute analytically the mean trapping time (MTT), a quantitative indicator characterizing the trapping efficiency of the trapping process. We show that in the non-fractal scale-free networks the MTT for both cases follows different scalings with the network order (number of network nodes), implying that trap's position has a significant effect on the trapping efficiency. In contrast, it is presented that for both cases in the fractal scale-free networks, the two leading scalings exhibit the same dependence on the network order, suggesting that the location of trap has no essential impact on the trapping efficiency. We also show that for both cases of the trapping problem, the trapping efficiency is more efficient in the non-fractal scale-free networks than in their fractal counterparts.

  1. Synthesis and Crystal Structures of Ni(II)/(III) and Zn(II) Complexes with Schiff Base Ligands

    International Nuclear Information System (INIS)

    Koo, Bon Kweon

    2013-01-01

    Coordination polymers are of great interest due to their intriguing structural motifs and potential applications in optical, electronic, magnetic, and porous materials. The most commonly used strategy for designing such materials relies on the utilization of multidentate N- or Odonor ligands which have the capacity to bridge between metal centers to form polymeric structures. The Schiff bases with N,O,S donor atoms are an useful source as they are readily available and easily form stable complexes with most transition metal ions. Schiff bases are also important intermediates in synthesis of some bioactive compounds and are potent anti-bacterial, anti-fungal, anticancer and antiviral compounds. In this work, the Schiff bases, Hapb and Hbpb, derived from 2-acetylpyridene or 2-benzoylpyridine and benzhydrazide were taken as trifunctional (N,N,O) monobasic ligand (Scheme 1). This ligand is of important because the π-delocalization of charge and the configurational flexibility of their molecular chain can give rise to a great variety of coordination modes. Although many metal.Schiff base complexes have been reported, the 1D, 2D, and 3D networks of coordination polymers linked through the bridging of ligands such as dicyanamide, N(CN) 2 - as coligand have been little published. In the process of working to extend the dimensionality of the metal-Schiff base complexes using benzilic acid as a bridging ligand, we obtained three simple metal (II)/(III) complexes of acetylpyridine/2-benzoyl pyridine based benzhydrazide ligand. Therefore, we report here the synthesis and crystal structures of the complexes

  2. Structural and IR-spectroscopic characterization of cadmium and lead(II) acesulfamates

    Energy Technology Data Exchange (ETDEWEB)

    Echeverria, Gustavo A.; Piro, Oscar E. [Univ. Nacional de La Plata (Argentina). Dept. de Fisica y Inst. IFLP (CONICET- CCT-La Plata); Parajon-Costa, Beatriz S.; Baran, Enrique J. [Univ. Nacional de La Plata (Argentina). Centro de Quimica Inorganica (CEQUINOR/CONICET- CCT-La Plata)

    2017-07-01

    Cadmium and lead(II) acesulfamate, Cd(C{sub 4}H{sub 4}NO{sub 4}S){sub 2} . 2H{sub 2}O and Pb(C{sub 4}H{sub 4}NO{sub 4}S){sub 2}, were prepared by the reaction of acesulfamic acid and the respective metal carbonates in aqueous solution, and characterized by elemental analysis. Their crystal structures were determined by single crystal X-ray diffraction methods. The Cd(II) compound crystallizes in the monoclinic space group P2{sub 1}/c with Z=4 and the corresponding Pb(II) salt in the triclinic space group P anti 1 with Z=2. In both salts, acesulfamate acts both as a bi-dentate ligand through its nitrogen and carbonyl oxygen atoms and also as a mono-dentate ligand through this same oxygen atom, giving rise to polymeric structures; in the Pb(II) salt the ligand also binds the cation through its sulfoxido oxygen atoms. The FTIR spectra of the compounds were recorded and are briefly discussed. Some comparisons with other related acesulfamate and saccharinate complexes are made.

  3. Cold trap disposed within a tank

    International Nuclear Information System (INIS)

    Kanbe, Mitsuru.

    1983-01-01

    Purpose: To improve the reliability and the durability of cold traps by simplifying the structure and recycling liquid metals without using electromagnetic pumps. Constitution: The reactor container is partitioned by an intermediate container enhousing primary recycling pumps and cold traps. The inlet and the exit for the liquid metal of each cold trap are opened to the outside and the inside of the intermediate container respectively. In such a structure, the pressure difference between the inside and the outside of the intermediate container is exerted on the cold traps due to the exhaust pressure of the recycling pumps in which the liquid metal flowing into the cold traps is purified through filters, cooled and then discharged from the exit to the cold plenum. In this way, liquid metal can be recycled without using an electromagnetic pump whose reliability has not yet been established. (Kamimura, M.)

  4. Structure and properties of dichloro(L-proline)cadmium(II) hydrate

    Energy Technology Data Exchange (ETDEWEB)

    Yukawa, Yasuhiko; Inomata, Yoshie; Takeuchi, Toshio [Jochi Univ., Tokyo (Japan). Faculty of Science and Technology

    1983-07-01

    An X-ray diffraction study of the title complex has been carried out. The crystal is orthorhombic, with the space group P2/sub 1/2/sub 1/2/sub 1/; Z=4, a=10.021(3), b=13.562(4), c=7.298(3) A. Block-diagonal least-squares refinements have led to the final R value of 0.035. The structure is very similar to that of dichloro(4-hydroxy-L-proline) cadmium(II), which has a one-dimensional polymer bridged by chlorine atoms and a carboxyl group like an infinite folding screen. The thermal behavior is, however, different from that of dichloro(4-hydroxy-L-proline) cadmium(II). The difference is likely to be due to a difference of the crystal structure, whether it contains intermolecular hydrogen bonds or not.

  5. Optical Trapping of Ion Coulomb Crystals

    Science.gov (United States)

    Schmidt, Julian; Lambrecht, Alexander; Weckesser, Pascal; Debatin, Markus; Karpa, Leon; Schaetz, Tobias

    2018-04-01

    The electronic and motional degrees of freedom of trapped ions can be controlled and coherently coupled on the level of individual quanta. Assembling complex quantum systems ion by ion while keeping this unique level of control remains a challenging task. For many applications, linear chains of ions in conventional traps are ideally suited to address this problem. However, driven motion due to the magnetic or radio-frequency electric trapping fields sometimes limits the performance in one dimension and severely affects the extension to higher-dimensional systems. Here, we report on the trapping of multiple barium ions in a single-beam optical dipole trap without radio-frequency or additional magnetic fields. We study the persistence of order in ensembles of up to six ions within the optical trap, measure their temperature, and conclude that the ions form a linear chain, commonly called a one-dimensional Coulomb crystal. As a proof-of-concept demonstration, we access the collective motion and perform spectrometry of the normal modes in the optical trap. Our system provides a platform that is free of driven motion and combines advantages of optical trapping, such as state-dependent confinement and nanoscale potentials, with the desirable properties of crystals of trapped ions, such as long-range interactions featuring collective motion. Starting with small numbers of ions, it has been proposed that these properties would allow the experimental study of many-body physics and the onset of structural quantum phase transitions between one- and two-dimensional crystals.

  6. Levitated superconductor ring trap (mini-RT) project - A new self-organized structure with strong plasma flow

    International Nuclear Information System (INIS)

    Ogawa, Y.; Himura, H.; Hishinuma, Y.

    2003-01-01

    Mahajan-Yoshida has theoretically developed a new relaxation state under the condition of a strong plasma flow, and proposed a possibility for confining high beta plasmas. In this self-organized state, two fluids (electron and ion) would relax to the condition given by the relation β + (V/V A ) 2 = const.. An internal coil device is suitable for studying a self-organized structure with strong plasma flow, because a strong toroidal flow is easily induced by introducing an appropriate radial electric field. We are constructing a Mini-RT device, which is equipping a floating coil with a high temperature superconductor (HTS) coil (R=0.15m, Ic=50kAturns). The magnetic field strength near the floating coil is around 0.1 T, and the plasma production with 2.45 GHz Electron Cyclotron Heating is planned. We are preparing several techniques to build up the radial electric field in the plasma such as the direct insertion of the electrode and so on. The utilization of direct orbit loss of high energy electrons produced by ECH might be an interesting method. The orbit calculation results show that the electrons with the energy of more than 10 keV would escape at the outer region of the plasma column, yielding the build-up of the radial electric field. The engineering aspect of the HTS coil is in progress. We have fabricated a small HTS coil (R=0.04 m and Ic= 2.6 kAturns), and succeeded in levitating it during four minutes with an accuracy of a few tens of micrometers. Since the HTS coil is excited by the external power supply, the persistent current switch for the HTS coil has been developed. The HTS coil system with the PCS coil has been fabricated and the excitation test has been carried out. We have succeeded in achieving a persistent current, and it is found that the decay constant of the coil current is evaluated to be around 40 hours and 6.5 hours at 20 K and 40 K, respectively. (author)

  7. Complexation of 1,3-dimorpholinopropane with Hg(II) and Zn(II) salts: Synthese, crystal structures and antibacterial studies

    Czech Academy of Sciences Publication Activity Database

    Goudarziafshar, H.; Yousefi, S.; Abbasityula, Y.; Dušek, Michal; Eigner, Václav; Rezaeivala, M.; Özbek, N.

    2015-01-01

    Roč. 31, č. 6 (2015), s. 1076-1084 ISSN 1001-4861 R&D Projects: GA ČR(CZ) GA14-03276S Institutional support: RVO:68378271 Keywords : crystal structure * 1,3-dimorpholinopropane * antibacterial activity * Hg(II) complex * Zn(II) complex Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 0.488, year: 2015

  8. Synthesis, crystal structure of and DFT calculations on bisglycinato-bis[p-(hydroxymethylpyridine]nickel(II

    Directory of Open Access Journals (Sweden)

    FANG FANG JIAN

    2010-09-01

    Full Text Available The main aim of this study was to investigate the relationship between mIn tA new Ni(II complex of bisglycinato-bis[p-(hydroxylmethylpy-ridine] was synthesized and characterized by elemental analysis, IR, UV–Vis spectroscopy and X-ray single crystal diffraction analysis. The thermal stability of the title complex was also determined. The complex adopts a distorted octahedral geometry and possesses inversion symmetry with the Ni(II ion as the center of inversion. Density function theory (DFT calculations of the structure, electronic absorption spectra, electron structure and natural population analysis (NPA at the B3LYP/LANL2DZ level of theory were performed. The predicted geometric parameters and electronic spectra were compared with the experimental values and they supported each other. The NPA results indicate that the electronic transitions were mainly derived from the contribution of an intra-ligand (IL transition, a ligand-to-metal charge transfer (LMCT transition and a d-d transition. The electron structure calculations suggest that the central Ni(II ion uses its 4s and 3d orbitals to form covalent bonds with coordinated N and O atoms. The calculated bond orders are also consistent with the thermal decomposition results. Based on vibrational analysis, the thermodynamic properties of the title complex were predicted and the correlative equations between these thermodynamic properties and temperature are also reported.

  9. Structure, magnetic properties, polarized neutron diffraction, and theoretical study of a copper(II) cubane.

    Science.gov (United States)

    Aronica, Christophe; Chumakov, Yurii; Jeanneau, Erwann; Luneau, Dominique; Neugebauer, Petr; Barra, Anne-Laure; Gillon, Béatrice; Goujon, Antoine; Cousson, Alain; Tercero, Javier; Ruiz, Eliseo

    2008-01-01

    The paper reports the synthesis, X-ray and neutron diffraction crystal structures, magnetic properties, high field-high frequency EPR (HF-EPR), spin density and theoretical description of the tetranuclear CuII complex [Cu4L4] with cubane-like structure (LH2=1,1,1-trifluoro-7-hydroxy-4-methyl-5-aza-hept-3-en-2-one). The simulation of the magnetic behavior gives a predominant ferromagnetic interaction J1 (+30.5 cm(-1)) and a weak antiferromagnetic interaction J2 (-5.5 cm(-1)), which correspond to short and long Cu-Cu distances, respectively, as evidence from the crystal structure [see formulate in text]. It is in agreement with DFT calculations and with the saturation magnetization value of an S=2 ground spin state. HF-EPR measurements at low temperatures (5 to 30 K) provide evidence for a negative axial zero-field splitting parameter D (-0.25+/-0.01 cm(-1)) plus a small rhombic term E (0.025+/-0.001 cm(-1), E/D = 0.1). The experimental spin distribution from polarized neutron diffraction is mainly located in the basal plane of the CuII ion with a distortion of yz-type for one CuII ion. Delocalization on the ligand (L) is observed but to a smaller extent than expected from DFT calculations.

  10. Ultra-Lightweight Nanocomposite Foams and Sandwich Structures for Space Structures Applications, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Space structures that are ultra-lightweight, and have gas barrier property, space durability, radiation resistance, EMI shielding, and high impact resistance are...

  11. Structural insight into activity enhancement and inhibition of H64A carbonic anhydrase II by imidazoles

    Directory of Open Access Journals (Sweden)

    Mayank Aggarwal

    2014-03-01

    Full Text Available Human carbonic anhydrases (CAs are zinc metalloenzymes that catalyze the hydration and dehydration of CO2 and HCO3−, respectively. The reaction follows a ping-pong mechanism, in which the rate-limiting step is the transfer of a proton from the zinc-bound solvent (OH−/H2O in/out of the active site via His64, which is widely believed to be the proton-shuttling residue. The decreased catalytic activity (∼20-fold lower with respect to the wild type of a variant of CA II in which His64 is replaced with Ala (H64A CA II can be enhanced by exogenous proton donors/acceptors, usually derivatives of imidazoles and pyridines, to almost the wild-type level. X-ray crystal structures of H64A CA II in complex with four imidazole derivatives (imidazole, 1-methylimidazole, 2-methylimidazole and 4-methylimidazole have been determined and reveal multiple binding sites. Two of these imidazole binding sites have been identified that mimic the positions of the `in' and `out' rotamers of His64 in wild-type CA II, while another directly inhibits catalysis by displacing the zinc-bound solvent. The data presented here not only corroborate the importance of the imidazole side chain of His64 in proton transfer during CA catalysis, but also provide a complete structural understanding of the mechanism by which imidazoles enhance (and inhibit when used at higher concentrations the activity of H64A CA II.

  12. A temperature-dependent theory for HeII: Application to the liquid structure factor

    International Nuclear Information System (INIS)

    Chela-Flores, J.; Ghassib, H.B.

    1981-08-01

    A temperature-dependent theory is presented for HeII, which is based on both a gauge-theoretic formulation as well as a mean-field (Hartree) approach. A simple model calculation is then performed within this framework for the liquid structure factor of the system. In particular, explicit expressions are obtained for the low-momentum-transfer and low-temperature limits, which seem to conform with the available experimental data. Further, the curvature of the structure factor is predicted, under these circumstances, to be only mildly dependent on temperature. Throughout, we compare and contrast with other theoretical attempts, including Feynman's. (author)

  13. Equilibrium vortex structures of type-II/1 superconducting films with washboard pinning landscapes

    Science.gov (United States)

    Wei, C. A.; Xu, X. B.; Xu, X. N.; Wang, Z. H.; Gu, M.

    2018-05-01

    We numerically study the equilibrium vortex structures of type-II/1 superconducting films with a periodic quasi-one-dimensional corrugated substrate. We show as a function of substrate period and pinning strength that, the vortex system displays a variety of vortex phases including arrays consisted of vortex clumps with different morphologies, ordered vortex stripes parallel and perpendicular to pinning troughs, and ordered one-dimensional vortex chains. Our simulations are helpful in understanding the structural modulations for extensive systems with both competing interactions and competing periodicities.

  14. OR TEP-II: a FORTRAN Thermal-Ellipsoid Plot Program for crystal structure illustrations

    International Nuclear Information System (INIS)

    Johnson, C.K.

    1976-03-01

    A computer program is described for drawing crystal structure illustrations using a mechanical plotter. Ball-and-stick type illustrations of a quality suitable for publication are produced with either spheres or thermal-motion probability ellipsoids on the atomic sites. The program can produce stereoscopic pairs of illustrations which aid in the visualization of complex packing arrangements of atoms and thermal motion patterns. Interatomic distances, bond angles, and principal axes of thermal motion are also calculated to aid the structural study. The most recent version of the program, OR TEP-II, has a hidden-line-elimination feature to omit those portions of atoms or bonds behind other atoms or bonds

  15. Concept and structure of instrumentation and control of the Atucha II nuclear power plant

    International Nuclear Information System (INIS)

    Garzon, D.; Roca, J.L.

    1987-01-01

    The general structure of instrumentation and control of Atucha II nuclear power plant as well as the technologies used, are described: concepts of functional decentralization and physical centralization; concept of functional group and functional complex; description of the technologies used (physical support) in the project of plant instrumentation and control; description of the different automation levels on the basis of concepts of control interface, automatism, regulation, group and subgroup controls; principles of signal conditioning; concept of announcement of alarms and state: supervisory computer, description of HAS (Hard wired Alarm System) and CAS (Computer Alarm System); application of the above mentioned structure to the project of another type of plants. (Author)

  16. OR TEP-II: a FORTRAN Thermal-Ellipsoid Plot Program for crystal structure illustrations

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, C.K.

    1976-03-01

    A computer program is described for drawing crystal structure illustrations using a mechanical plotter. Ball-and-stick type illustrations of a quality suitable for publication are produced with either spheres or thermal-motion probability ellipsoids on the atomic sites. The program can produce stereoscopic pairs of illustrations which aid in the visualization of complex packing arrangements of atoms and thermal motion patterns. Interatomic distances, bond angles, and principal axes of thermal motion are also calculated to aid the structural study. The most recent version of the program, OR TEP-II, has a hidden-line-elimination feature to omit those portions of atoms or bonds behind other atoms or bonds.

  17. Structure of a Complete Mediator-RNA Polymerase II Pre-Initiation Complex.

    Science.gov (United States)

    Robinson, Philip J; Trnka, Michael J; Bushnell, David A; Davis, Ralph E; Mattei, Pierre-Jean; Burlingame, Alma L; Kornberg, Roger D

    2016-09-08

    A complete, 52-protein, 2.5 million dalton, Mediator-RNA polymerase II pre-initiation complex (Med-PIC) was assembled and analyzed by cryo-electron microscopy and by chemical cross-linking and mass spectrometry. The resulting complete Med-PIC structure reveals two components of functional significance, absent from previous structures, a protein kinase complex and the Mediator-activator interaction region. It thereby shows how the kinase and its target, the C-terminal domain of the polymerase, control Med-PIC interaction and transcription. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. Electronic structure and electric fields gradients of crystalline Sn(II) and Sn(IV) compounds

    International Nuclear Information System (INIS)

    Terra, J.; Guenzburger, D.

    1991-01-01

    The electronic structures of clusters representing crystalline compounds of Sn(II) and Sn(IV) were investigated, employing the first-principles Discrete Variational method and Local Density theory. Densities of states and related parameters were obtained and compared with experimental measurements and with results from band structure calculations. Effects of cluster size and of cluster truncated bonds are discussed. Electric field gradients at the Sn nucleus were calculated; results are analysed in terms of charge distribution and chemical bonding in the crystals. (author)

  19. Coordination structure of adsorbed Zn(II) at Water-TiO2 interfaces

    Energy Technology Data Exchange (ETDEWEB)

    He, G.; Pan, G.; Zhang, M.; Waychunas, G.A.

    2011-01-15

    The local structure of aqueous metal ions on solid surfaces is central to understanding many chemical and biological processes in soil and aquatic environments. Here, the local coordination structure of hydrated Zn(II) at water-TiO{sub 2} interfaces was identified by extended X-ray absorption fine structure (EXAFS) and X-ray absorption near-edge structure (XANES) spectroscopy combined with density functional theory (DFT) calculations. A nonintegral coordination number of average {approx}4.5 O atoms around a central Zn atom was obtained by EXAFS analysis. DFT calculations indicated that this coordination structure was consistent with the mixture of 4-coordinated bidentate binuclear (BB) and 5-coordinated bidentate mononuclear (BM) metastable equilibrium adsorption (MEA) states. The BB complex has 4-coordinated Zn, while the monodentate mononuclear (MM) complex has 6-coordinated Zn, and a 5-coordinated adsorbed Zn was found in the BM adsorption mode. DFT calculated energies showed that the lower-coordinated BB and BM modes were thermodynamically more favorable than the higher-coordinated MM MEA state. The experimentally observed XANES fingerprinting provided additional direct spectral evidence of 4- and 5-coordinated Zn-O modes. The overall spectral and computational evidence indicated that Zn(II) can occur in 4-, 5-, and 6-oxygen coordinated sites in different MEA states due to steric hindrance effects, and the coexistence of different MEA states formed the multiple coordination environments.

  20. An Overview of Materials Structures for Extreme Environments Efforts for 2015 SBIR Phases I and II

    Science.gov (United States)

    Nguyen, Hung D.; Steele, Gynelle C.

    2017-01-01

    Technological innovation is the overall focus of NASA's Small Business Innovation Research (SBIR) program. The program invests in the development of innovative concepts and technologies to help NASA's mission directorates address critical research and development needs for Agency projects. This report highlights innovative SBIR 2015 Phase I and II projects that specifically address areas in Materials and Structures for Extreme Environments, one of six core competencies at NASA Glenn Research Center. Each article describes an innovation, defines its technical objective, and highlights NASA applications as well as commercial and industrial applications. Ten technologies are featured: metamaterials-inspired aerospace structures, metallic joining to advanced ceramic composites, multifunctional polyolefin matrix composite structures, integrated reacting fluid dynamics and predictive materials degradation models for propulsion system conditions, lightweight inflatable structural airlock (LISA), copolymer materials for fused deposition modeling 3-D printing of nonstandard plastics, Type II strained layer superlattice materials development for space-based focal plane array applications, hydrogenous polymer-regolith composites for radiation-shielding materials, a ceramic matrix composite environmental barrier coating durability model, and advanced composite truss printing for large solar array structures. This report serves as an opportunity for NASA engineers, researchers, program managers, and other personnel to learn about innovations in this technology area as well as possibilities for collaboration with innovative small businesses that could benefit NASA programs and projects.

  1. Ball-grid array architecture for microfabricated ion traps

    Science.gov (United States)

    Guise, Nicholas D.; Fallek, Spencer D.; Stevens, Kelly E.; Brown, K. R.; Volin, Curtis; Harter, Alexa W.; Amini, Jason M.; Higashi, Robert E.; Lu, Son Thai; Chanhvongsak, Helen M.; Nguyen, Thi A.; Marcus, Matthew S.; Ohnstein, Thomas R.; Youngner, Daniel W.

    2015-05-01

    State-of-the-art microfabricated ion traps for quantum information research are approaching nearly one hundred control electrodes. We report here on the development and testing of a new architecture for microfabricated ion traps, built around ball-grid array (BGA) connections, that is suitable for increasingly complex trap designs. In the BGA trap, through-substrate vias bring electrical signals from the back side of the trap die to the surface trap structure on the top side. Gold-ball bump bonds connect the back side of the trap die to an interposer for signal routing from the carrier. Trench capacitors fabricated into the trap die replace area-intensive surface or edge capacitors. Wirebonds in the BGA architecture are moved to the interposer. These last two features allow the trap die to be reduced to only the area required to produce trapping fields. The smaller trap dimensions allow tight focusing of an addressing laser beam for fast single-qubit rotations. Performance of the BGA trap as characterized with 40Ca+ ions is comparable to previous surface-electrode traps in terms of ion heating rate, mode frequency stability, and storage lifetime. We demonstrate two-qubit entanglement operations with 171Yb+ ions in a second BGA trap.

  2. Ball-grid array architecture for microfabricated ion traps

    International Nuclear Information System (INIS)

    Guise, Nicholas D.; Fallek, Spencer D.; Stevens, Kelly E.; Brown, K. R.; Volin, Curtis; Harter, Alexa W.; Amini, Jason M.; Higashi, Robert E.; Lu, Son Thai; Chanhvongsak, Helen M.; Nguyen, Thi A.; Marcus, Matthew S.; Ohnstein, Thomas R.; Youngner, Daniel W.

    2015-01-01

    State-of-the-art microfabricated ion traps for quantum information research are approaching nearly one hundred control electrodes. We report here on the development and testing of a new architecture for microfabricated ion traps, built around ball-grid array (BGA) connections, that is suitable for increasingly complex trap designs. In the BGA trap, through-substrate vias bring electrical signals from the back side of the trap die to the surface trap structure on the top side. Gold-ball bump bonds connect the back side of the trap die to an interposer for signal routing from the carrier. Trench capacitors fabricated into the trap die replace area-intensive surface or edge capacitors. Wirebonds in the BGA architecture are moved to the interposer. These last two features allow the trap die to be reduced to only the area required to produce trapping fields. The smaller trap dimensions allow tight focusing of an addressing laser beam for fast single-qubit rotations. Performance of the BGA trap as characterized with 40 Ca + ions is comparable to previous surface-electrode traps in terms of ion heating rate, mode frequency stability, and storage lifetime. We demonstrate two-qubit entanglement operations with 171 Yb + ions in a second BGA trap

  3. Syntheses, structural characterization and spectroscopic studies of cadmium(II)-metal(II) cyanide complexes with 4-(2-aminoethyl)pyridine

    Science.gov (United States)

    Karaağaç, Dursun; Kürkçüoğlu, Güneş Süheyla; Şenyel, Mustafa; Hökelek, Tuncer

    2017-02-01

    Three new cadmium(II)-metal(II) cyanide complexes, [Cd(4aepy)2(H2O)2][Ni(CN)4] (1), [Cd(4aepy)2(H2O)2][Pd(CN)4] (2) and [Cd(4aepy)2(H2O)2][Pt(CN)4] (3) [4aepy = 4-(2-aminoethyl)pyridine], have been synthesized and characterized by elemental, thermal, FT-IR and Raman spectral analyses. The crystal structures of 1 and 2 have been determined by single crystal X-ray diffraction technique, in which they crystallize in the monoclinic system and C2/c space group. The M(II) [M(II) = Ni(II), Pd(II) and Pt(II)] ions are coordinated with the carbon atoms of the four cyanide groups in the square planar geometries and the [M(CN)4]2- ions act as counter ions. The Cd(II) ions display an N4O2 coordination sphere with a distorted octahedral geometry, the nitrogen donors belonging to four molecules of the organic 4aepy that act as unidentate ligands and two oxygen atoms from aqua ligands. 3D supramolecular structures of 1 and 2 were occurred by M⋯π and hydrogen bonding (Nsbnd H⋯N and Osbnd H⋯N) interactions. Vibrational assignments of all the observed bands were given and the spectral properties were also supported the crystal structures of the complexes. A possible decompositions of the complexes were investigated in the temperature range 30-800 °C in the static atmosphere.

  4. Lead(ii) soaps: crystal structures, polymorphism, and solid and liquid mesophases.

    Science.gov (United States)

    Martínez-Casado, F J; Ramos-Riesco, M; Rodríguez-Cheda, J A; Redondo-Yélamos, M I; Garrido, L; Fernández-Martínez, A; García-Barriocanal, J; da Silva, I; Durán-Olivencia, M; Poulain, A

    2017-07-05

    The long-chain members of the lead(ii) alkanoate series or soaps, from octanoate to octadecanoate, have been thoroughly characterized by means of XRD, PDF analysis, DSC, FTIR, ssNMR and other techniques, in all their phases and mesophases. The crystal structures at room temperature of all of the members of the series are now solved, showing the existence of two polymorphic forms in the room temperature crystal phase, different to short and long-chain members. Only nonanoate and decanoate present both forms, and this polymorphism is proven to be monotropic. At higher temperature, these compounds present a solid mesophase, defined as rotator, a liquid crystal phase and a liquid phase, all of which have a similar local arrangement. Since some lead(ii) soaps appear as degradation compounds in oil paintings, the solved crystal structures of lead(ii) soaps can now be used as fingerprints for their detection using X-ray diffraction. Pair distribution function analysis on these compounds is very similar in the same phases and mesophases for the different members, showing the same short range order. This observation suggests that this technique could also be used in the detection of these compounds in disordered phases or in the initial stages of formation in paintings.

  5. Ion Trap Quantum Computing

    Science.gov (United States)

    2011-12-01

    variations of ion traps, including (1) the cylindrically symmetric 3D ring trap; (2) the linear trap with a combination of cavity QED; (#) the symmetric...concepts of quantum information. The major demonstration has been the test of a Bell inequality as demonstrated by Rowe et al. [50] and a decoherence...famous physics experiment [62]. Wolfgang Paul demonstrated a similar apparatus during his Nobel Prize speech [63]. This device is hyperbolic- parabolic

  6. Atomistic modeling of structure II gas hydrate mechanics: Compressibility and equations of state

    Directory of Open Access Journals (Sweden)

    Thomas M. Vlasic

    2016-08-01

    Full Text Available This work uses density functional theory (DFT to investigate the poorly characterized structure II gas hydrates, for various guests (empty, propane, butane, ethane-methane, propane-methane, at the atomistic scale to determine key structure and mechanical properties such as equilibrium lattice volume and bulk modulus. Several equations of state (EOS for solids (Murnaghan, Birch-Murnaghan, Vinet, Liu were fitted to energy-volume curves resulting from structure optimization simulations. These EOS, which can be used to characterize the compressional behaviour of gas hydrates, were evaluated in terms of their robustness. The three-parameter Vinet EOS was found to perform just as well if not better than the four-parameter Liu EOS, over the pressure range in this study. As expected, the Murnaghan EOS proved to be the least robust. Furthermore, the equilibrium lattice volumes were found to increase with guest size, with double-guest hydrates showing a larger increase than single-guest hydrates, which has significant implications for the widely used van der Waals and Platteeuw thermodynamic model for gas hydrates. Also, hydrogen bonds prove to be the most likely factor contributing to the resistance of gas hydrates to compression; bulk modulus was found to increase linearly with hydrogen bond density, resulting in a relationship that could be used predictively to determine the bulk modulus of various structure II gas hydrates. Taken together, these results fill a long existing gap in the material chemical physics of these important clathrates.

  7. Atomistic modeling of structure II gas hydrate mechanics: Compressibility and equations of state

    Energy Technology Data Exchange (ETDEWEB)

    Vlasic, Thomas M.; Servio, Phillip; Rey, Alejandro D., E-mail: alejandro.rey@mcgill.ca [Department of Chemical Engineering, McGill University, Montreal H3A 0C5 (Canada)

    2016-08-15

    This work uses density functional theory (DFT) to investigate the poorly characterized structure II gas hydrates, for various guests (empty, propane, butane, ethane-methane, propane-methane), at the atomistic scale to determine key structure and mechanical properties such as equilibrium lattice volume and bulk modulus. Several equations of state (EOS) for solids (Murnaghan, Birch-Murnaghan, Vinet, Liu) were fitted to energy-volume curves resulting from structure optimization simulations. These EOS, which can be used to characterize the compressional behaviour of gas hydrates, were evaluated in terms of their robustness. The three-parameter Vinet EOS was found to perform just as well if not better than the four-parameter Liu EOS, over the pressure range in this study. As expected, the Murnaghan EOS proved to be the least robust. Furthermore, the equilibrium lattice volumes were found to increase with guest size, with double-guest hydrates showing a larger increase than single-guest hydrates, which has significant implications for the widely used van der Waals and Platteeuw thermodynamic model for gas hydrates. Also, hydrogen bonds prove to be the most likely factor contributing to the resistance of gas hydrates to compression; bulk modulus was found to increase linearly with hydrogen bond density, resulting in a relationship that could be used predictively to determine the bulk modulus of various structure II gas hydrates. Taken together, these results fill a long existing gap in the material chemical physics of these important clathrates.

  8. Atomistic modeling of structure II gas hydrate mechanics: Compressibility and equations of state

    Science.gov (United States)

    Vlasic, Thomas M.; Servio, Phillip; Rey, Alejandro D.

    2016-08-01

    This work uses density functional theory (DFT) to investigate the poorly characterized structure II gas hydrates, for various guests (empty, propane, butane, ethane-methane, propane-methane), at the atomistic scale to determine key structure and mechanical properties such as equilibrium lattice volume and bulk modulus. Several equations of state (EOS) for solids (Murnaghan, Birch-Murnaghan, Vinet, Liu) were fitted to energy-volume curves resulting from structure optimization simulations. These EOS, which can be used to characterize the compressional behaviour of gas hydrates, were evaluated in terms of their robustness. The three-parameter Vinet EOS was found to perform just as well if not better than the four-parameter Liu EOS, over the pressure range in this study. As expected, the Murnaghan EOS proved to be the least robust. Furthermore, the equilibrium lattice volumes were found to increase with guest size, with double-guest hydrates showing a larger increase than single-guest hydrates, which has significant implications for the widely used van der Waals and Platteeuw thermodynamic model for gas hydrates. Also, hydrogen bonds prove to be the most likely factor contributing to the resistance of gas hydrates to compression; bulk modulus was found to increase linearly with hydrogen bond density, resulting in a relationship that could be used predictively to determine the bulk modulus of various structure II gas hydrates. Taken together, these results fill a long existing gap in the material chemical physics of these important clathrates.

  9. Structure and Function of p97 and Pex1/6 Type II AAA+ Complexes.

    Science.gov (United States)

    Saffert, Paul; Enenkel, Cordula; Wendler, Petra

    2017-01-01

    Protein complexes of the Type II AAA+ (ATPases associated with diverse cellular activities) family are typically hexamers of 80-150 kDa protomers that harbor two AAA+ ATPase domains. They form double ring assemblies flanked by associated domains, which can be N-terminal, intercalated or C-terminal to the ATPase domains. Most prominent members of this family include NSF (N-ethyl-maleimide sensitive factor), p97/VCP (valosin-containing protein), the Pex1/Pex6 complex and Hsp104 in eukaryotes and ClpB in bacteria. Tremendous efforts have been undertaken to understand the conformational dynamics of protein remodeling type II AAA+ complexes. A uniform mode of action has not been derived from these works. This review focuses on p97/VCP and the Pex1/6 complex, which both structurally remodel ubiquitinated substrate proteins. P97/VCP plays a role in many processes, including ER- associated protein degradation, and the Pex1/Pex6 complex dislocates and recycles the transport receptor Pex5 from the peroxisomal membrane during peroxisomal protein import. We give an introduction into existing knowledge about the biochemical and cellular activities of the complexes before discussing structural information. We particularly emphasize recent electron microscopy structures of the two AAA+ complexes and summarize their structural differences.

  10. Towards trapped antihydrogen

    CERN Document Server

    Jorgensen, L V; Bertsche, W; Boston, A; Bowe, P D; Cesar, C L; Chapman, S; Charlton, M; Fajans, J; Fujiwara, M C; Funakoshi, R; Gill, D R; Hangst, J S; Hayano, R S; Hydomako, R; Jenkins, M J; Kurchaninov, L; Madsen, N; Nolan, P; Olchanski, K; Olin, A; Page, R D; Povilus, A; Robicheaux, F; Sarid, E; Silveira, D M; Storey, J W; Thompson, R I; van der Werf, D P; Wurtele, J S; Yamazaki, Y

    2008-01-01

    Substantial progress has been made in the last few years in the nascent field of antihydrogen physics. The next big step forward is expected to be the trapping of the formed antihydrogen atoms using a magnetic multipole trap. ALPHA is a new international project that started to take data in 2006 at CERN’s Antiproton Decelerator facility. The primary goal of ALPHA is stable trapping of cold antihydrogen atoms to facilitate measurements of its properties. We discuss the status of the ALPHA project and the prospects for antihydrogen trapping.

  11. Synthesis, structural characterization, and pro-apoptotic activity of 1-indanone thiosemicarbazone platinum(II) and palladium(II) complexes: potential as antileukemic agents.

    Science.gov (United States)

    Gómez, Natalia; Santos, Diego; Vázquez, Ramiro; Suescun, Leopoldo; Mombrú, Alvaro; Vermeulen, Monica; Finkielsztein, Liliana; Shayo, Carina; Moglioni, Albertina; Gambino, Dinorah; Davio, Carlos

    2011-08-01

    In the search for alternative chemotherapeutic strategies against leukemia, various 1-indanone thiosemicarbazones, as well as eight novel platinum(II) and palladium(II) complexes, with the formula [MCl₂(HL)] and [M(HL)(L)]Cl, derived from two 1-indanone thiosemicarbazones were synthesized and tested for antiproliferative activity against the human leukemia U937 cell line. The crystal structure of [Pt(HL1)(L1)]Cl·2MeOH, where L1=1-indanone thiosemicarbazone, was solved by X-ray diffraction. Free thiosemicarbazone ligands showed no antiproliferative effect, but the corresponding platinum(II) and palladium(II) complexes inhibited cell proliferation and induced apoptosis. Platinum(II) complexes also displayed selective apoptotic activity in U937 cells but not in peripheral blood monocytes or the human hepatocellular carcinoma HepG2 cell line used to screen for potential hepatotoxicity. Present findings show that, in U937 cells, 1-indanone thiosemicarbazones coordinated to palladium(II) were more cytotoxic than those complexed with platinum(II), although the latter were found to be more selective for leukemic cells suggesting that they are promising compounds with potential therapeutic application against hematological malignancies. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Geometry and electronic structure of an impurity-trapped exciton in the Cs2GeF6 crystal doped with U4+. The 5f17s1 manifold

    International Nuclear Information System (INIS)

    Ordejon, B.; Seijo, L.; Barandiaran, Z.

    2007-01-01

    Complete text of publication follows: Excitons trapped at impurity centres in highly ionic crystals were first described by McClure and Pedrini [Phys. Rev. B 32, 8465 (1985)] as excited states consisting of a bound electron-hole pair with the hole localized on the impurity and the electron on nearby lattice sites, and a very short impurity-ligand bond length. In this work we present a detailed microscopic characterization of an impurity - trapped exciton in Cs 2 GeF 6 doped with U 4+ . Its electronic structure has been studied by means of CASSCF/CASPT2/SOCI relativistic ab initio model potential (AIMP) embedded-cluster calculations on (UF 6 ) 2- and (UF 6 Cs 8 ) 6+ clusters embedded in Cs 2 GeF 6 . The local geometry of the impurity-trapped exciton, the potential energy curves, and the multi electronic wavefunctions, have been obtained as direct, non-empirical results of the methods. The calculated excited states appear to be significantly delocalized outside the UF 6 volume and their U-F bond length turns out to be very short, closer to that of a pentavalent uranium defect than to that of a tetravalent uranium defect. The wavefunctions of these excited states show a dominant U 5f 1 7s 1 configuration character. This result has never been anticipated by simpler models and reveals the unprecedented ability of diffuse orbitals of f-element impurities to act as electron traps in ionic crystals

  13. Halide/pseudohalide complexes of cadmium(II) with benzimidazole: Synthesis, crystal structures and fluorescence properties

    Science.gov (United States)

    Zhao, Hai-Yan; Yang, Fu-Li; Li, Na; Wang, Xiao-Jing

    2017-11-01

    Two new dinuclear Cd(II) complexes, [CdL1Cl2]2·H2O (1) and [CdL1(N3)2]2·CH3OH (2) and one dicyanamide bridged one-dimensional polynuclear network [CdL1(μ1,5-dca)dca]n (3) of the potentially tridentate NNN-donor Schiff base 2-((1H-benzimidazol-2-yl-ethylimino)-methyl)pyridine (L1) and another dinucler Cd(II) complex [CdL2Cl(dca)]2 (4) of a similar NNN-donor Schiff base ligand 2-((1H-benzimidazol-2-yl-propylimino)-methyl)pyridine (L2), have been synthesized and characterized by elemental analyses, IR and single crystal X-ray crystallography. The ligands L1 and L2 are [1 + 1] condensation products of pyridine-2-carbaldehyde with 2-aminoethyl-1H-benzimidazole and 2-aminopropyl-1H-benzimidazole, respectively. In the complexes 1 and 4 the two Cd(II) centers are held together by the bridged chloride ligands, while in 2 the two Cd(II) centers are bridged by μ1,1-azide ions. Complex 3 has a one-dimensional infinite chain structure in which Cd(II) ions are bridged by single dicyanamide groups in end-to-end fashion. All the metal centers have a distorted octahedral geometry and H-bonding or π⋯π interactions are operative to bind the complex units in the solid state. Furthermore, these complexes have been investigated by thermogravimetric analyses and fluorescence spectra.

  14. Mitigating unaccounted fishing mortality from gillnet and traps

    NARCIS (Netherlands)

    Uhlmann, S.S.; Broadhurst, M.K.

    2015-01-01

    Gillnets and traps often are considered to have fewer holistic environmental impacts than active fishing gears. However, in addition to the targeted catches, gillnets and traps still cause unwanted mortalities due to (i) discarding, (ii) ghost fishing of derelict gear, (iii) depredation, (iv)

  15. Colloquium: Quantum Networks with Trapped Ions

    Science.gov (United States)

    2010-04-28

    observed be- tween two ions held in the same trap Eichmann et al., 1993; DeVoe and Brewer, 1996. Type-II links have the advantage of being less sensitive...Childress, E. Jiang, J. Togan, J. Maze, F. Jelezko, A. S. Zibrov, P. R. Hemmer, and M. D. Lukin, 2007, Science 316, 1312. Eichmann , U., J. C. Bergquist

  16. Adsorption and desorption of Cd(II) onto titanate nanotubes and efficient regeneration of tubular structures

    International Nuclear Information System (INIS)

    Wang, Ting; Liu, Wen; Xu, Nan; Ni, Jinren

    2013-01-01

    Highlights: ► Satisfactory reuse of TNTs due to easy regeneration of tubular structures. ► TNTs regeneration using only 2% of NaOH needed for virgin TNTs preparation. ► Excellent regeneration attributed to steady TNTs skeleton and complex form of TNTs-OCd + OH − onto adsorbed TNTs. -- Abstract: Efficient regeneration of desorbed titanate nanotubes (TNTs) was investigated with cycled Cd(II) adsorption and desorption processes. After desorption of Cd (II) from TNTs using 0.1 M HNO 3 , regeneration could be simply achieved with only 0.2 M NaOH at ambient temperature, i.e. 2% of the NaOH needed for virgin TNTs preparation at 130 °C. The regenerated TNTs displayed similar adsorption capacity of Cd(II) even after six recycles, while significant reduction could be detected for desorbed TNTs without regeneration. The virgin TNTs, absorbed TNTs, desorbed TNTs and regenerated TNTs were systematically characterized. As results, the ion-exchange mechanism with Na + in TNTs was convinced with obvious change of -TiO(ONa) 2 by FTIR spectroscopy. The easy recovery of the damaged tubular structures proved by TEM and XRD was ascribed to asymmetric distribution of H + and Na + on the surface side and interlayer region of TNTs. More importantly, the cost-effective regeneration was found possibly related to complex form of TNTs-OCd + OH − onto the adsorbed TNTs, which was identified with help of X-ray photoelectron spectroscopy, and further indicated due to high relevance to an unexpected mole ratio of 1:1 between exchanged Na + and absorbed Cd(II)

  17. Investigations of the ground-state hyperfine atomic structure and beta decay measurement prospects of 21Na with improved laser trapping techniques

    International Nuclear Information System (INIS)

    Rowe, Mary A.

    1999-01-01

    This thesis describes an experiment in which a neutral atom laser trap loaded with radioactive 21 Na was improved and then used for measurements. The sodium isotope (half-life=22 sec) is produced on line at the 88in cyclotron at Lawrence Berkeley National Laboratory. The author developed an effective magnesium oxide target system which is crucial to deliver a substantive beam of 21 Na to the experiment. Efficient manipulation of the 21 Na beam with lasers allowed 30,000 atoms to be contained in a magneto-optical trap. Using the cold trapped atoms, the author measured to high precision the hyperfine splitting of the atomic ground state of 21 Na. She measured the 3S 1/2 (F=1,m=0)-3S 1/2 (F=2,m=0) atomic level splitting of 21 Na to be 1,906,471,870±200 Hz. Additionally, she achieved initial detection of beta decay from the trap and evaluated the prospects of precision beta decay correlation studies with trapped atoms

  18. Investigations of the ground-state hyperfine atomic structure and beta decay measurement prospects of 21Na with improved laser trapping techniques

    Energy Technology Data Exchange (ETDEWEB)

    Rowe, Mary Anderson [Univ. of California, Berkeley, CA (United States)

    1999-05-01

    This thesis describes an experiment in which a neutral atom laser trap loaded with radioactive 21Na was improved and then used for measurements. The sodium isotope (half-life=22 sec) is produced on line at the 88 in. cyclotron at Lawrence Berkeley National Laboratory. The author developed an effective magnesium oxide target system which is crucial to deliver a substantive beam of 21Na to the experiment. Efficient manipulation of the 21Na beam with lasers allowed 30,000 atoms to be contained in a magneto-optical trap. Using the cold trapped atoms, the author measured to high precision the hyperfine splitting of the atomic ground state of 21Na. She measured the 3S1/2(F=1,m=0)-3S1/2(F=2,m=0) atomic level splitting of 21Na to be 1,906,471,870±200 Hz. Additionally, she achieved initial detection of beta decay from the trap and evaluated the prospects of precision beta decay correlation studies with trapped atoms.

  19. Crystal structure of metallo DNA duplex containing consecutive Watson-Crick-like T-Hg(II)-T base pairs.

    Science.gov (United States)

    Kondo, Jiro; Yamada, Tom; Hirose, Chika; Okamoto, Itaru; Tanaka, Yoshiyuki; Ono, Akira

    2014-02-24

    The metallo DNA duplex containing mercury-mediated T-T base pairs is an attractive biomacromolecular nanomaterial which can be applied to nanodevices such as ion sensors. Reported herein is the first crystal structure of a B-form DNA duplex containing two consecutive T-Hg(II)-T base pairs. The Hg(II) ion occupies the center between two T residues. The N3-Hg(II) bond distance is 2.0 Å. The relatively short Hg(II)-Hg(II) distance (3.3 Å) observed in consecutive T-Hg(II)-T base pairs suggests that the metallophilic attraction could exist between them and may stabilize the B-form double helix. To support this, the DNA duplex is largely distorted and adopts an unusual nonhelical conformation in the absence of Hg(II). The structure of the metallo DNA duplex itself and the Hg(II)-induced structural switching from the nonhelical form to the B-form provide the basis for structure-based design of metal-conjugated nucleic acid nanomaterials. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Solving nucleic acid structures by molecular replacement: examples from group II intron studies

    International Nuclear Information System (INIS)

    Marcia, Marco; Humphris-Narayanan, Elisabeth; Keating, Kevin S.; Somarowthu, Srinivas; Rajashankar, Kanagalaghatta; Pyle, Anna Marie

    2013-01-01

    Strategies for phasing nucleic acid structures by molecular replacement, using both experimental and de novo designed models, are discussed. Structured RNA molecules are key players in ensuring cellular viability. It is now emerging that, like proteins, the functions of many nucleic acids are dictated by their tertiary folds. At the same time, the number of known crystal structures of nucleic acids is also increasing rapidly. In this context, molecular replacement will become an increasingly useful technique for phasing nucleic acid crystallographic data in the near future. Here, strategies to select, create and refine molecular-replacement search models for nucleic acids are discussed. Using examples taken primarily from research on group II introns, it is shown that nucleic acids are amenable to different and potentially more flexible and sophisticated molecular-replacement searches than proteins. These observations specifically aim to encourage future crystallographic studies on the newly discovered repertoire of noncoding transcripts

  1. A pheromone-baited trap for monitoring the Indian meal moth, Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae).

    Science.gov (United States)

    Mullen, M A.; Dowdy, A K.

    2001-07-01

    A pheromone-baited trap was developed to monitor the Indian meal moth in grocery stores and similar areas where visible traps are not desirable. The trap can be used under shelves and against walls. As a shelf mount, the trap is in close proximity to the food packages and may capture emerging insects before they mate. The trap can also be used as a hanging trap similar to the Pherocon II. When used as a shelf or wall mount, it was as effective as the Pherocon II, but when used as a hanging trap significantly fewer insects were captured.

  2. Mn(HPO3): A new manganese (II) phosphite with a condensed structure

    International Nuclear Information System (INIS)

    Chung, U-Chan; Mesa, Jose L.; Pizarro, Jose L.; Jubera, Veronique; Lezama, Luis; Arriortua, Maria I.; Rojo, Teofilo

    2005-01-01

    A new manganese (II) phosphite with the formula Mn(HPO 3 ) has been synthesised under mild hydrothermal conditions and autogenous pressure. Large pink coloured single crystals were obtained, allowing the resolution of the structure by x-ray diffraction. Mn(HPO 3 ) crystallises in the P2 1 /c monoclinic space group with a=8.036(3) A, b=8.240(3) A, c=10.410(3) A, β=124.73(3) deg. and Z=8. The structure consists of a three-dimensional, compact framework of edge sharing MnO 6 octahedra linked to phosphite groups via oxygens. The presence of the phosphite anion has been confirmed by IR spectroscopy. Mn(HPO 3 ) presents a high thermal stability limit of 580 deg. C, before rapid transformation to Mn 2 P 2 O 7 occurs. Photoluminescence and diffuse reflectance spectroscopy studies show the presence of high spin Mn(II) in significantly distorted octahedral coordination with Dq and Racah parameters of Dq=820, B=910 and C=3135 cm -1 . The ESR spectra, performed at different temperatures, are isotropic with a g-value of 2.00(1). Magnetic measurements indicate global antiferromagnetic interactions with a ferromagnetic transition at 15 K, attributed to a canting of the antiferromagneticaly aligned spins. - Graphical abstract: Crystal structure of Mn(HPO 3 )

  3. Structural Fluctuations and Thermophysical Properties of Molten II-VI Compounds

    Science.gov (United States)

    Su, Ching-Hua; Zhu, Shen; Li, Chao; Scripa, R.; Lehoczky, Sandra L.; Kim, Y. W.; Baird, J. K.; Lin, B.; Ban, Heng; Benmore, Chris

    2003-01-01

    The objectives of the project are to conduct ground-based experimental and theoretical research on the structural fluctuations and thermophysical properties of molten II-VI compounds to enhance the basic understanding of the existing flight experiments in microgravity materials science programs as well as to study the fundamental heterophase fluctuation phenomena in these melts by: 1) conducting neutron scattering analysis and measuring quantitatively the relevant thermophysical properties of the II-VI melts (such as viscosity, electrical conductivity, thermal diffusivity and density) as well as the relaxation characteristics of these properties to advance the understanding of the structural properties and the relaxation phenomena in these melts and 2) performing theoretical analyses on the melt systems to interpret the experimental results. All the facilities required for the experimental measurements have been procured, installed and tested. It has long been recognized that liquid Te presents a unique case having properties between those of metals and semiconductors. The electrical conductivity for Te melt increases rapidly at melting point, indicating a semiconductor-metal transition. Te melts comprise two features, which are usually considered to be incompatible with each other: covalently bound atoms and metallic-like behavior. Why do Te liquids show metallic behavior? is one of the long-standing issues in liquid metal physics. Since thermophysical properties are very sensitive to the structural variations of a melt, we have conducted extensive thermophysical measurements on Te melt.

  4. Electron transfer and atom exchange between aqueous Fe(II) and structural Fe(III) in clays. Role in U and Hg(II) transformations

    Energy Technology Data Exchange (ETDEWEB)

    Scherer, Michelle [Univ. of Iowa, Iowa City, IA (United States)

    2016-08-31

    During this project, we investigated Fe electron transfer and atom exchange between aqueous Fe(II) and structural Fe(III) in clay minerals. We used selective chemical extractions, enriched Fe isotope tracer experiments, computational molecular modeling, and Mössbauer spectroscopy. Our findings indicate that structural Fe(III) in clay minerals is reduced by aqueous Fe(II) and that electron transfer occurs when Fe(II) is sorbed to either basal planes and edge OH-groups of clay mineral. Findings from highly enriched isotope experiments suggest that up to 30 % of the Fe atoms in the structure of some clay minerals exhanges with aqueous Fe(II). First principles calculations using a small polaron hopping approach suggest surprisingly fast electron mobility at room temperature in a nontronite clay mineral and are consistent with temperature dependent Mössbauer data Fast electron mobility suggests that electrons may be able to conduct through the mineral fast enough to enable exchange of Fe between the aqueous phase and clay mineral structure. over the time periods we observed. Our findings suggest that Fe in clay minerals is not as stable as previously thought.

  5. Trans-ligand-dependent arrangement (bent or linear) of Pt II-bound dialkylcyanamide ligands: Molecular structure of trans-dichloro(dimethylcyanamide)(dimethyl sulfoxide)platinum(II)

    Science.gov (United States)

    Anisimova, Tatyana B.; Bokach, Nadezhda A.; Fritsky, Igor O.; Haukka, Matti

    2011-11-01

    The title compound, trans-[PtCl 2(NCNMe 2)(Me 2SO)], is the first example of the structurally characterized Pt II species having the nitrile and the sulfoxide ligands in the trans-position to each other. The most significant feature of this structure is the non-linear arrangement of the Pt sbnd N1 sbnd C1 fragment providing the rare case of the bent form of the dialkylcyanamide ligand.

  6. Versatile electrostatic trap

    NARCIS (Netherlands)

    van Veldhoven, J.; Bethlem, H.L.; Schnell, M.; Meijer, G.

    2006-01-01

    A four electrode electrostatic trap geometry is demonstrated that can be used to combine a dipole, quadrupole, and hexapole field. A cold packet of ND315 molecules is confined in both a purely quadrupolar and hexapolar trapping field and additionally, a dipole field is added to a hexapole field to

  7. Liquid metal cold trap

    International Nuclear Information System (INIS)

    Hundal, R.

    1976-01-01

    A cold trap assembly for removing impurities from a liquid metal is described. A hole between the incoming impure liquid metal and purified outgoing liquid metal acts as a continuous bleed means and thus prevents the accumulation of cover gases within the cold trap assembly

  8. Determination of Ni(II) crystal structure by powder x-ray diffraction ...

    African Journals Online (AJOL)

    X-ray powder diffraction pattern was used to determine the length of the unit cell, “a”, the lattice structure type, and the number of atoms per unit cell of Ni(II) crystal. The “a” value was determined to be 23.66 ± 0.005 Å, particle size of 34.87 nm, volume 13.24 Å and Strain value ε = 9.8 x 10-3. The cell search on PXRD patterns ...

  9. Can Cu(II) ions be doped into the crystal structure of potassium hydrogen tartrate?

    OpenAIRE

    Srinivasan, Bikshandarkoil R.; Remesh, H.

    2015-01-01

    The differing binding preferences of the hydrogen tartrate ligand (HC4H4O6)- namely {\\mu}7-octadentate mode for potassium ion and bidentate mode for cupric ion rules out the doping (incorporation) of any Cu(II) ion into the crystal structure of potassium hydrogen tartrate. Hence, the claim of growth of copper doped potassium hydrogen tartrate viz. K0.96Cu0.04C4H5O6 by Mathivanan and Haris, Indian J Pure App Phys 51 (2013) 851-859 is untenable.

  10. Photometrical analysis of the Neck-Line structure of Comet Bennet 1970II

    International Nuclear Information System (INIS)

    Fulle, M.; Sedmak, G.

    1988-01-01

    The Kimura and Liu (1977) analysis of the motion in space of cometary dust tail grains, which furnished information on the size-dependence of the dust ejection velocity from the inner coma and the size distribution on a millimetric scale, is presently applied to the Neck-Line Structure (NLS) displayed by Comet Bennett 1970II at the begining of May, 1970. Attention is given to two photographs of the comet which have been analyzed by digital image processing in order to extract reliable photometric data; the strong excess of millimetric grains noted is in agreement with the Fulle (1987) results for preperihelion times. 24 references

  11. Carborane-containing urea-based inhibitors of glutamate carboxypeptidase II: Synthesis and structural characterization

    Czech Academy of Sciences Publication Activity Database

    Youn, S.; Kim, K.I.; Ptáček, Jakub; Ok, K.; Nováková, Zora; Kim, Y.; Koo, J.; Bařinka, Cyril; Byun, Y.

    2015-01-01

    Roč. 25, č. 22 (2015), s. 5232-5236 ISSN 0960-894X R&D Projects: GA ČR GAP301/12/1513; GA MŠk(CZ) ED1.1.00/02.0109 Grant - others:GA MŠk(CZ) CZ.1.07/2.3.00/30.0045 Institutional support: RVO:86652036 Keywords : Carborane * Glutamate carboxypeptidase II * X-ray crystal structure Subject RIV: FR - Pharmacology ; Medidal Chemistry Impact factor: 2.486, year: 2015

  12. Structural diversity of three Cu(II) compounds based on a new tripodal zwitterionic ligand: Syntheses, structures and properties

    Science.gov (United States)

    Zhou, Jie; Zhao, Jing-Song; Feng, Jing; Zhang, Xiao-Feng; Xu, Jian; Du, Lin; Xie, Ming-Jin; Zhao, Qi-Hua

    2018-03-01

    An exploration of reactions of 1,1‧,1″-(benzene-1,3,5-triyltris(methylene))tris(4-carboxypyridinium)-tribromide (H3LBr3) with Cu(II) salt under different pH conditions has led to the formation of three complexes, [Cu(HL)2(H2O)3]·4(ClO4)·3H2O (1), [Cu2(HL)(μ3-OH)(μ2-H2O)(H2O)2]·4(ClO4)·6H2O (2), and [Cu3(L)2Cl6(H2O)4]·4H2O (3). Single-crystal X-ray analyses revealed that complex 1 displays a discrete mononuclear structure with the ligand in a bowl-shaped configuration. Complex 2 possesses a tetranuclear 1D beaded chain structure. While complex 3 features a discrete trinuclear 'H-type' structure with the ligand in a chair-like configuration. The distinct compositions and structures of 1-3 are mainly ascribed to the different pH values of the reaction solution, the influences of anions, as well as the configurations which the zwitterion ligands adopt. The magnetic properties of 2, and the photoluminescence properties of 2, and 3 have been investigated. Moreover, powder X-ray diffraction, infrared spectroscopy, and elemental analysis were also performed.

  13. Structural, spectral, DFT and biological studies on macrocyclic mononuclear ruthenium (II) complexes

    Science.gov (United States)

    Muthukkumar, M.; Kamal, C.; Venkatesh, G.; Kaya, C.; Kaya, S.; Enoch, Israel V. M. V.; Vennila, P.; Rajavel, R.

    2017-11-01

    Macrocyclic mononuclear ruthenium (II) complexes have been synthesized by condensation method [Ru (L1, L2, L3) Cl2] L1 = (C36 H31 N9), L2= (C42H36N8), L3= (C32H32 N8)]. These ruthenium complexes have been established by elemental analyses and spectroscopic techniques (Fourier transform infrared spectroscopy (FT-IR), 1H- nuclear magnetic resonance (NMR), 13C- NMR and Electrospray ionization mass spectrometry (ESI-MS)). The coordination mode of the ligand has been confirmed and the octahedral geometry around the ruthenium ion has been revealed. Binding affinity and binding mode of ruthenium (II) complexes with Bovine serum Albumin (BSA) have been characterized by Emission spectra analysis. UV-Visible and fluorescence spectroscopic techniques have also been utilized to examine the interaction between ligand and its complexes L1, L2, & L3 with BSA. Chemical parameters and molecular structure of Ru (II) complexes L1H, L2H, & L3H have been determined by DFT coupled with B3LYP/6-311G** functional in both the gaseous and aqueous phases.

  14. The crystal structure of paramagnetic copper(ii) oxalate (CuC2O4):

    DEFF Research Database (Denmark)

    Christensen, Axel Nørlund; Lebech, Bente; Andersen, Niels Hessel

    2014-01-01

    Synthetic copper(ii) oxalate, CuC2O4, was obtained in a precipitation reaction between a copper(ii) solution and an aqueous solution of oxalic acid. The product was identified from its conventional X-ray powder patterns which match that of the copper mineral Moolooite reported to have...... the composition CuC2O4·0.44H2O. Time resolved in situ investigations of the thermal decomposition of copper(ii) oxalate using synchrotron X-ray powder diffraction showed that in air the compound converts to Cu2O at 215 °C and oxidizes to CuO at 345 °C. Thermo gravimetric analysis performed in an inert Ar....... The crystal structure consists of a random stacking of CuC2O4 micro-crystallites where half the Cu-atoms are placed at (2a) and the other half at (2b) positions with the corresponding oxalate molecules centred around the corresponding (2b) and (2a) site positions, respectively. The diffraction patterns...

  15. Synthesis, structure and luminescence properties of zinc (II) complexes with terpyridine derivatives as ligands

    International Nuclear Information System (INIS)

    Chen Xuegang; Zhou Quanguo; Cheng Yanxiang; Geng Yanhou; Ma Dongge; Xie Zhiyuan; Wang Lixiang

    2007-01-01

    Five zinc (II) complexes (1-5) with 4'-phenyl-2,2':6',2''-terpyridine (ptpy) derivatives as ligands have been synthesized and fully characterized. The para-position of phenyl in ptpy is substituted by the group (R), i.e. tert-butyl (t-Bu), hexyloxy (OHex), carbazole-9-yl (Cz), naphthalen-1-yl-phenyl-amine-N-yl (NPA) and diphenyl amine-N-yl (DPA), with different electron-donating ability. With increasing donor ability of the R, the emission color of the complexes in film was modulated from violet (392 nm) to reddish orange (604 nm). The photoexcited luminescence exhibits significant solvatochromism because the emission of the complexes involves the intra-ligand charge transfer (ILCT) excited state. The electrochemical investigations show that the complexes with stronger electro-donating substituent have lower oxidation potential and then higher HOMO level. The electroluminescence (EL) properties of these zinc (II) complexes were studied with the device structure of ITO/PEDOT/Zn (II) complex: PBD:PMMA/BCP/AlQ/LiF/Al. Complexes 3, 4 and 5 exhibit EL wavelength at 552, 600 and 609 nm with maximum current efficiency of 5.28, 2.83 and 2.00 cd/A, respectively

  16. Trapping radioactive ions

    CERN Document Server

    Kluge, Heinz-Jürgen

    2004-01-01

    Trapping devices for atomic and nuclear physics experiments with radioactive ions are becoming more and more important at accelerator facilities. While about ten years ago only one online Penning trap experiment existed, namely ISOLTRAP at ISOLDE/CERN, meanwhile almost every radioactive beam facility has installed or plans an ion trap setup. This article gives an overview on ion traps in the operation, construction or planing phase which will be used for fundamental studies with short-lived radioactive nuclides such as mass spectrometry, laser spectroscopy and nuclear decay spectroscopy. In addition, this article summarizes the use of gas cells and radiofrequency quadrupole (Paul) traps at different facilities as a versatile tool for ion beam manipulation like retardation, cooling, bunching, and cleaning.

  17. Trapping radioactive ions

    International Nuclear Information System (INIS)

    Kluge, H.-J.; Blaum, K.

    2004-01-01

    Trapping devices for atomic and nuclear physics experiments with radioactive ions are becoming more and more important at accelerator facilities. While about ten years ago only one online Penning trap experiment existed, namely ISOLTRAP at ISOLDE/CERN, meanwhile almost every radioactive beam facility has installed or plans an ion trap setup. This article gives an overview on ion traps in the operation, construction or planing phase which will be used for fundamental studies with short-lived radioactive nuclides such as mass spectrometry, laser spectroscopy and nuclear decay spectroscopy. In addition, this article summarizes the use of gas cells and radiofrequency quadrupole (Paul) traps at different facilities as a versatile tool for ion beam manipulation like retardation, cooling, bunching, and cleaning

  18. Crystal structure of the coordination polymer [FeIII2{PtII(CN4}3

    Directory of Open Access Journals (Sweden)

    Maksym Seredyuk

    2015-01-01

    Full Text Available The title complex, poly[dodeca-μ-cyanido-diiron(IIItriplatinum(II], [FeIII2{PtII(CN4}3], has a three-dimensional polymeric structure. It is built-up from square-planar [PtII(CN4]2− anions (point group symmetry 2/m bridging cationic [FeIIIPtII(CN4]+∞ layers extending in the bc plane. The FeII atoms of the layers are located on inversion centres and exhibit an octahedral coordination sphere defined by six N atoms of cyanide ligands, while the PtII atoms are located on twofold rotation axes and are surrounded by four C atoms of the cyanide ligands in a square-planar coordination. The geometrical preferences of the two cations for octahedral and square-planar coordination, respectively, lead to a corrugated organisation of the layers. The distance between neighbouring [FeIIIPtII(CN4]+∞ layers corresponds to the length a/2 = 8.0070 (3 Å, and the separation between two neighbouring PtII atoms of the bridging [PtII(CN4]2− groups corresponds to the length of the c axis [7.5720 (2 Å]. The structure is porous with accessible voids of 390 Å3 per unit cell.

  19. Tracers of Chromospheric Structure. I. Observations of Ca II K and Hα in M Dwarfs

    Science.gov (United States)

    Walkowicz, Lucianne M.; Hawley, Suzanne L.

    2009-02-01

    We report on our observing program4This paper is based on observations obtained with the Apache Point Observatory 3.5 m telescope, which is owned and operated by the Astrophysical Research Consortium. Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. to capture simultaneous spectra of Ca II and Balmer lines in a sample of nearby M3 dwarfs. Our goal is to investigate the chromospheric temperature structure required to produce these lines at the observed levels. We find a strong positive correlation between instantaneous measurements of Ca II K and the Balmer lines in active stars, although these lines may not be positively correlated in time-resolved measurements. The relationship between Hα and Ca II K remains ambiguous for weak and intermediate activity stars, with Hα absorption corresponding to a range of Ca II K emission. A similar relationship is also observed between Ca II K and the higher-order Balmer lines. As our sample consists of a single spectral type, correlations between these important chromospheric tracers cannot be ascribed to continuum effects, as suggested by other authors. These data confirm prior nonsimultaneous observations of the Hα line behavior with increasing activity, showing an initial increase in the Hα absorption with increasing Ca II K emission, prior to Hα filling in and eventually becoming a pure emission line in the most active stars. We also compare our optical measurements with archival UV and X-ray measurements, finding a positive correlation between the chromospheric and coronal emission for both high and intermediate activity stars. We compare our results with previous determinations of the active fraction of low-mass stars

  20. The Structure of the Young Star Cluster NGC 6231. II. Structure, Formation, and Fate

    Science.gov (United States)

    Kuhn, Michael A.; Getman, Konstantin V.; Feigelson, Eric D.; Sills, Alison; Gromadzki, Mariusz; Medina, Nicolás; Borissova, Jordanka; Kurtev, Radostin

    2017-12-01

    The young cluster NGC 6231 (stellar ages ˜2-7 Myr) is observed shortly after star formation activity has ceased. Using the catalog of 2148 probable cluster members obtained from Chandra, VVV, and optical surveys (Paper I), we examine the cluster’s spatial structure and dynamical state. The spatial distribution of stars is remarkably well fit by an isothermal sphere with moderate elongation, while other commonly used models like Plummer spheres, multivariate normal distributions, or power-law models are poor fits. The cluster has a core radius of 1.2 ± 0.1 pc and a central density of ˜200 stars pc-3. The distribution of stars is mildly mass segregated. However, there is no radial stratification of the stars by age. Although most of the stars belong to a single cluster, a small subcluster of stars is found superimposed on the main cluster, and there are clumpy non-isotropic distributions of stars outside ˜4 core radii. When the size, mass, and age of NGC 6231 are compared to other young star clusters and subclusters in nearby active star-forming regions, it lies at the high-mass end of the distribution but along the same trend line. This could result from similar formation processes, possibly hierarchical cluster assembly. We argue that NGC 6231 has expanded from its initial size but that it remains gravitationally bound.

  1. Preparation, structural characterization, and catalytic performance of Pd(II) and Pt(II) complexes derived from cellulose Schiff base

    Science.gov (United States)

    Baran, Talat; Yılmaz Baran, Nuray; Menteş, Ayfer

    2018-05-01

    In this study, we reported production, characterization, and catalytic behavior of two novel heterogeneous palladium(II) and platinum(II) catalysts derived from cellulose biopolymer. In order to eliminate the use of toxic organic or inorganic solvents and to reduce the use of excess energy in the coupling reactions, we have developed a very simple, rapid, and eco-friendly microwave irradiation protocol. The developed microwave-assisted method of Suzuki cross coupling reactions produced excellent reaction yields in the presence of cellulose supported palladium and platinum (II) catalysts. Moreover, the catalysts easily regenerated after simple filtration, and they gave good reusability. This study revealed that the designed catalysts and method provide clean, simple, rapid, and impressive catalytic performance for Suzuki coupling reactions.

  2. Synthesis, NMR characterization, X-ray crystal structure of Co(II) Ni(II) and Cu(II) complexes of a pyridine containing self-assembling

    International Nuclear Information System (INIS)

    Ranjbar, M.; Taghavipour, M.; Moghimi, A.; Aghabozorg, H.

    2002-01-01

    In the recent years, the self-assembling systems have been attracted chemists. The intermolecular bond in such systems mainly consists of ion pairing and hydrogen bonding [1,2]. The reaction between self-assembling system liquid LH 2 (py dc=2,6-pyridinedicarboxylic acid and py da=2,6- pyridine diamin) with cobalt (II) nitrate, nickel (II) chloride, and copper (II) acetate in water leads to the formation of self- assemble coordination complexes, [py da.H] 2 [M(py dc) 2 ]. H 2 O, M=Co(II),Ni(II), and Cu(II). The characterization was performed using elemental analysis, ESI mass spectroscopy, 1 H and 13 C NMR and X-ray crystallography. The crystal systems are monoclinic with space group P2 1 /n and four molecules per unit cell. These complexes shows 13 C NMR resonances of cationic counter ion [(py dc,H)] + in DMSO- d 6 but no signal corresponding to the two coordinated ligands [py dc] 2- The metal atoms are six-coordinated with a distorted octahedral geometry. The two [py de] 2- units are almost perpendicular to each other

  3. Sorption Mechanisms of Cesium on Cu II2Fe II(CN) 6and Cu II3[Fe III(CN) 6] 2Hexacyanoferrates and Their Relation to the Crystalline Structure

    Science.gov (United States)

    Ayrault, S.; Jimenez, B.; Garnier, E.; Fedoroff, M.; Jones, D. J.; Loos-Neskovic, C.

    1998-12-01

    CuII2FeII(CN)6·xH2O and CuII3[FeIII(CN)6]2·xH2O can be prepared with reproducible chemical compositions and structures after careful washing. They have cubicFmoverline3mstructures with iron vacancies. In CuII2FeII(CN)6, copper occupies two different sites: Cu1 in position 4blinked to Fe through the CN groups, and Cu2 not linked to the CN groups and partially occupying the interstitial 24epositions. The second type of site is not present in CuII3[FeIII(CN)6]2. Sorption kinetics and isotherms were determined for cesium on both hexacyanoferrates by batch experiments. On CuII3[FeIII(CN)6]2, the maximum uptake is only 0.073 Cs/Fe (at./at.). On CuII2FeII(CN)6, the uptake reaches 1.5 Cs/Fe. The sorption kinetics include at least two steps: at1/2variation until approximately 72 h and then a slow evolution studied up to 6 months. The sorption mechanism is complex. The main process seems to be diffusion of ion pairs, followed by a reorganization of the solid, resulting in one or more new solid phases. The presence of the Cu2 site seems to play a favorable role in the sorption. Owing to its good midterm stability and the first rapid step of exchange, CuII2FeII(CN)6·xH2O seems to be one of the most promising compounds for the recovery of cesium from nuclear liquid wastes.

  4. Hyperfine structure in the Gd II spectrum and the nuclear electric quadrupole moment of 157Gd

    International Nuclear Information System (INIS)

    Clieves, H.P.; Steudel, A.

    1979-01-01

    The hyperfine structure of 157 Gd was investigated in 20 Gd II lines by means of a photoelectric recording Fabry-Perot interferometer with digital data processing. The hyperfine splitting factors, A and B, were obtained by computer fits to the observed line structures. Using a multiconfigurational set of wave functions in intermediate coupling derived by Wyart, mono-electronic parameters were deduced by a parametric treatment. The nuclear electric quadrupole moment of 157 Gd was evaluated from the quadrupole interaction of the 5d electron in 4f 7 5d6s, the 5d electron in 4f 7 5d6p, and the 6p electron in 4f 7 5d6p. The three values obtained for the quadrupole moment agree very well. The final result, corrected for Sternheimer shielding, is Q( 157 Gd) = 1.34(7) x 10 -24 cm 2 . (orig.) [de

  5. An Overview of 2014 SBIR Phase I and Phase II Materials Structures for Extreme Environments

    Science.gov (United States)

    Nguyen, Hung D.; Steele, Gynelle C.; Morris, Jessica R.

    2015-01-01

    NASA's Small Business Innovation Research (SBIR) program focuses on technological innovation by investing in development of innovative concepts and technologies to help NASA mission directorates address critical research needs for Agency programs. This report highlights nine of the innovative SBIR 2014 Phase I and Phase II projects that emphasize one of NASA Glenn Research Center's six core competencies-Materials and Structures for Extreme Environments. The technologies cover a wide spectrum of applications such as high temperature environmental barrier coating systems, deployable space structures, solid oxide fuel cells, and self-lubricating hard coatings for extreme temperatures. Each featured technology describes an innovation, technical objective, and highlights NASA commercial and industrial applications. This report provides an opportunity for NASA engineers, researchers, and program managers to learn how NASA SBIR technologies could help their programs and projects, and lead to collaborations and partnerships between the small SBIR companies and NASA that would benefit both.

  6. Fine-structure excitation of Fe II and Fe III due to collisions with electrons

    Science.gov (United States)

    Wan, Yier; Qi, Yueying; Favreau, Connor; Loch, Stuart; Stancil, P.; Ballance, Connor; McLaughlin, Brendan

    2018-06-01

    Atomic data of iron peak elements are of great importance in astronomical observations. Among all the ionization stages of iron, Fe II and Fe III are of particular importance because of the high cosmic abundance, relatively low ionization potential and complex open d-shell atomic structure. Fe II and Fe III emission are observed from nearly all classes of astronomical objects over a wide spectral range from the infrared to the ultraviolet. To meaningfully interpret these spectra, astronomers have to employ highly complex modeling codes with reliable collision data to simulate the astrophysical observations. The major aim of this work is to provide reliable atomic data for diagnostics. We present new collision strengths and effective collisions for electron impact excitation of Fe II and Fe III for the forbidden transitions among the fine-structure levels of the ground terms. A very fine energy mesh is used for the collision strengths and the effective collision strengths are calculated over a wide range of electron temperatures of astrophysical importance (10-2000 K). The configuration interaction state wave functions are generated with a scaled Thomas-Fermi-Dirac-Amaldi (TFDA) potential, while the R-matrix plus intermediate coupling frame transformation (ICFT), Breit-Pauli R-matrix and Dirac R-matrix packages are used to obtain collision strengths. Influences of the different methods and configuration expansions on the collisional data are discussed. Comparison is made with earlier theoretical work and differences are found to occur at the low temperatures considered here.This work was funded by NASA grant NNX15AE47G.

  7. Structure of the Ni(II) complex of Escherichia coli peptide deformylase and suggestions on deformylase activities depending on different metal(II) centres.

    Science.gov (United States)

    Yen, Ngo Thi Hai; Bogdanović, Xenia; Palm, Gottfried J; Kühl, Olaf; Hinrichs, Winfried

    2010-02-01

    Crystal structures of polypeptide deformylase (PDF) of Escherichia coli with nickel(II) replacing the native iron(II) have been solved with chloride and formate as metal ligands. The chloro complex is a model for the correct protonation state of the hydrolytic hydroxo ligand and the protonated status of the Glu133 side chain as part of the hydrolytic mechanism. The ambiguity that recently some PDFs have been identified with Zn(2+) ion as the active-site centre whereas others are only active with Fe(2+) (or Co(2+), Ni(2+) is discussed with respect to Lewis acid criteria of the metal ion and substrate activation by the CD loop.

  8. Synthesis, structure and some properties of a manganese(II) benzoate containing diimine

    Science.gov (United States)

    Paul, Pranajit; Roy, Subhadip; Sarkar, Sanjoy; Chowdhury, Shubhamoy; Purkayastha, R. N. Dutta; Raghavaiah, Pallepogu; McArdle, Patrick; Deb, Lokesh; Devi, Sarangthem Indira

    2015-12-01

    A new monomeric manganese(II) benzoate complex containing nitrogen donor 2,2‧-bipyridine, [Mn(OBz)2(bipy)(H2O)] (OBz = benzoate, bipy = 2,2‧-bipyridine) has been synthesized from aqueous methanol medium and characterized by analytical, spectroscopic and single crystal X-ray diffraction studies. The compound exhibits moderate to appreciable antimicrobial activity. The complex crystallizes in space group P21/n. Mn(II) atom is ligated by two N atoms of bipyridine, three O atoms from a monodentate and a bidentate benzoate ligand and a water molecule forming distorted octahedral structure. The coordinated water molecule forms intramolecular hydrogen bonds and links the monomer molecules into hydrogen bonded dimer. The hydrogen bonded dimers are involved in intermolecular C-H···O and π-π stacking interactions. Density functional theory (DFT) computation was carried out to compute the frequencies of relevant vibrational modes and electronic properties, the results are in compliance with the experimentally obtained structural and spectral data.

  9. Heat-induced reorganization of the structure of photosystem II membranes: role of oxygen evolving complex.

    Science.gov (United States)

    Busheva, Mira; Tzonova, Iren; Stoitchkova, Katerina; Andreeva, Atanaska

    2012-12-05

    The sensitivity of the green plants' photosystem II (PSII) to high temperatures is investigated in PSII enriched membranes and in membranes, from which the oxygen evolving complex is removed. Using steady-state 77 K fluorescence and resonance Raman spectroscopy we analyze the interdependency between the temperature-driven changes in structure and energy distribution in the PSII supercomplex. The results show that the heat treatment induces different reduction of the 77 K fluorescence emission in both types of investigated membranes: (i) an additional considerable decrease of the overall fluorescence emission in Tris-washed membranes as compared to the native membranes; (ii) a transition point at 42°C(,) observed only in native membranes; (iii) a sharp reduction of the PSII core fluorescence in Tris-washed membranes at temperatures higher than 50°C; (iv) a 3 nm red-shift of F700 band's maximum in Tris-washed membranes already at 20°C and its further shift by 1 nm at temperature increase. Both treatments intensified their action by increasing the aggregation and dissociation of the peripheral light harvesting complexes. The oxygen-evolving complex, in addition to its main function to produce O(2), increases the thermal stability of PSII core by strengthening the connection between the core and the peripheral antenna proteins and by keeping their structural integrity. Copyright © 2012 Elsevier B.V. All rights reserved.

  10. Structural Fluctuation and Thermophysical Properties of Molten II-VI Compounds

    Science.gov (United States)

    2003-01-01

    The objectives of the project is to conduct ground-based experimental and theoretical research on the structural fluctuations and thermophysical properties of molten II-VI compounds to enhance the basic understanding of the existing flight experiments in microgravity materials science programs and to study the fundamental heterophase fluctuations phenomena in these melts by: 1) Conducting neutron scattering analysis and measuring quantitatively the relevant thermophysical properties of the II-VI melts such as viscosity, electrical conductivity, thermal diffusivity and density as well as the relaxation characteristics of these properties to advance the understanding of the structural properties and the relaxation phenomena in these melts and 2) Performing theoretical analyses on the melt systems to interpret the experimental results. All the facilities required for the experimental measurements have been procured, installed and tested. A relaxation phenomenon, which shows a slow drift of the measured thermal conductivity toward the equilibrium value after cooling of the sample, was observed for the first time. An apparatus based on the transient torque induced by a rotating magnetic field has been developed to determine the viscosity and electrical conductivity of semiconducting liquids. Viscosity measurements on molten tellurium showed similar relaxation behavior as the measured diffusivity. Neutron scattering experiments were performed on the HgTe and HgZnTe melts and the results on pair distribution showed better resolution than previous reported.

  11. Petro-structural, geochemical and carbon and oxygen isotopic study on carbonates crosscuting the Oman Ophiolite peridotites: evidence of polygenic CO2 trapping

    Science.gov (United States)

    Noël, J.; Godard, M.; Martinez, I.; Oliot, E.; Williams, M. J.; Rodriguez, O.; Chaduteau, C.; Gouze, P.

    2017-12-01

    Carbon trapping in ophiolitic peridotites contributes to the global carbon cycle between solid Earth and its outer envelopes (through subduction and/or modern alteration). To investigate this process, we performed petro-structural (microtomography, EBSD, EPMA) and geochemical studies (LA-ICP-MS, carbon and oxygen isotopes on bulk and minerals using SHRIMP) of harzburgites cored in the Oman Ophiolite. Studied harzburgites are highly serpentinized (> 90 %) and crosscut by 3 generations of carbonates (> 20 Vol%) with compositions from calcite to dolomite (Mg/Ca = 0-0.85). Type 1 carbonates are fine penetrative veinlets and mesh core after olivine. They have low REE (e.g., Yb = 0.08-0.23 x CI-chondrite) and negative Ce anomalies. They have δ13CPDB = -15.2 to 1.10‰ and δ18OSMOW = 17.5 to 33.7‰, suggesting precipitation temperatures up to 110°C. Type 2 carbonates are pluri-mm veins bounded by cm-thick serpentinized vein selvages, oriented dominantly parallel to mantle foliation. Dynamic recrystallization is observed, indicating polygenetic formation: well crystallized calcite with REE abundances similar to Type 1 carbonates are locally replaced by small dolomite and calcite grains with higher REE (e.g., Yb = 0.35-1.0 x CI-chondrite) and positive Gd anomaly. Type 2 carbonates have δ13CPDB = -12.6 to -4.1‰ and δ18OSMOW = 25.0 to 32.7‰, suggesting precipitation temperatures from 10 to 60°C. Type 3 carbonates are late pluri-mm to cm veins reactivating Type 2 veins. They consist of small grains of dolomite and calcite with REE abundances similar to recrystallized Type 2 carbonates. Type 3 carbonates have δ13CPDB = -8.3 to -5.8‰ and δ18OSMOW = 28.8 to 32.7‰, suggesting precipitation temperatures 100°C). Formation of carbonate veins (Type 2) indicates localization of fluid flux, while serpentinization remains the dominant alteration process. Low T carbonate veins (Type 3) remain the main flow path through ophiolitic peridotites. Our study suggests that

  12. Twinned low-temperature structures of tris(ethylenediamine)zinc(II) sulfate and tris(ethylenediamine)copper(II) sulfate

    NARCIS (Netherlands)

    Lutz, M.

    2010-01-01

    Tris(ethylenediamine)zinc(II) sulfate, [Zn(C2H8N2)3]SO4, (I), undergoes a reversible solid–solid phase transition during cooling, accompanied by a lowering of the symmetry from high-trigonal P31c to low-trigonal P3 and by merohedral twinning. The molecular symmetries of the cation and anion change

  13. Virtual sensors for active noise control in acoustic-structural coupled enclosures using structural sensing: part II--Optimization of structural sensor placement.

    Science.gov (United States)

    Halim, Dunant; Cheng, Li; Su, Zhongqing

    2011-04-01

    The work proposed an optimization approach for structural sensor placement to improve the performance of vibro-acoustic virtual sensor for active noise control applications. The vibro-acoustic virtual sensor was designed to estimate the interior sound pressure of an acoustic-structural coupled enclosure using structural sensors. A spectral-spatial performance metric was proposed, which was used to quantify the averaged structural sensor output energy of a vibro-acoustic system excited by a spatially varying point source. It was shown that (i) the overall virtual sensing error energy was contributed additively by the modal virtual sensing error and the measurement noise energy; (ii) each of the modal virtual sensing error system was contributed by both the modal observability levels for the structural sensing and the target acoustic virtual sensing; and further (iii) the strength of each modal observability level was influenced by the modal coupling and resonance frequencies of the associated uncoupled structural/cavity modes. An optimal design of structural sensor placement was proposed to achieve sufficiently high modal observability levels for certain important panel- and cavity-controlled modes. Numerical analysis on a panel-cavity system demonstrated the importance of structural sensor placement on virtual sensing and active noise control performance, particularly for cavity-controlled modes.

  14. Cu(II) and Co(II) complexes of benzimidazole derivative: Structures, catecholase like activities and interaction studies with hydrogen peroxide

    Science.gov (United States)

    Kumari, Babli; Adhikari, Sangita; Matalobos, Jesús Sanmartín; Das, Debasis

    2018-01-01

    Present study describes the synthesis and single crystal X-ray structures of two metal complexes of benzimidazole derivative (PBI), viz. the Cu(II) complex, [Cu(PBI)2(NCS)]ClO4 (1) and a Co(II) complex, [Co(PBI)2(NCS)1.75Cl0.25] (2). The Cu(II) complex (1) shows catecholase like activity having Kcat = 1.84 × 104 h-1. Moreover, interactions of the complexes with hydrogen peroxide have been investigated using fluorescence spectroscopy. The interaction constant of 1 and 2 for H2O2 are 6.67 × 102 M-1 and 1.049 × 103 M-1 while their detection limits for H2O2 are 3.37 × 10-7 M and 2.46 × 10-7 M respectively.

  15. Structural elucidation of the hormonal inhibition mechanism of the bile acid cholate on human carbonic anhydrase II

    Energy Technology Data Exchange (ETDEWEB)

    Boone, Christopher D. [University of Florida, PO Box 100267, Gainesville, FL 32610 (United States); Tu, Chingkuang [University of Florida, PO Box 100245, Gainesville, FL 32610 (United States); McKenna, Robert, E-mail: rmckenna@ufl.edu [University of Florida, PO Box 100267, Gainesville, FL 32610 (United States)

    2014-06-01

    The structure of human carbonic anhydrase II in complex with cholate has been determined to 1.54 Å resolution. Elucidation of the novel inhibition mechanism of cholate will aid in the development of a nonsulfur-containing, isoform-specific therapeutic agent. The carbonic anhydrases (CAs) are a family of mostly zinc metalloenzymes that catalyze the reversible hydration/dehydration of CO{sub 2} into bicarbonate and a proton. Human isoform CA II (HCA II) is abundant in the surface epithelial cells of the gastric mucosa, where it serves an important role in cytoprotection through bicarbonate secretion. Physiological inhibition of HCA II via the bile acids contributes to mucosal injury in ulcerogenic conditions. This study details the weak biophysical interactions associated with the binding of a primary bile acid, cholate, to HCA II. The X-ray crystallographic structure determined to 1.54 Å resolution revealed that cholate does not make any direct hydrogen-bond interactions with HCA II, but instead reconfigures the well ordered water network within the active site to promote indirect binding to the enzyme. Structural knowledge of the binding interactions of this nonsulfur-containing inhibitor with HCA II could provide the template design for high-affinity, isoform-specific therapeutic agents for a variety of diseases/pathological states, including cancer, glaucoma, epilepsy and osteoporosis.

  16. Structure of the P{sub II} signal transduction protein of Neisseria meningitidis at 1.85 Å resolution

    Energy Technology Data Exchange (ETDEWEB)

    Nichols, Charles E. [Division of Structural Biology, Henry Wellcome Building for Genomic Medicine, University of Oxford, Roosevelt Drive, Oxford OX3 7BN (United Kingdom); Sainsbury, Sarah; Berrow, Nick S.; Alderton, David [The Oxford Protein Production Facility, Henry Wellcome Building for Genomic Medicine, University of Oxford, Roosevelt Drive, Oxford OX3 7BN (United Kingdom); Saunders, Nigel J. [The Bacterial Pathogenesis and Functional Genomics Group, The Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE (United Kingdom); Stammers, David K. [Division of Structural Biology, Henry Wellcome Building for Genomic Medicine, University of Oxford, Roosevelt Drive, Oxford OX3 7BN (United Kingdom); The Oxford Protein Production Facility, Henry Wellcome Building for Genomic Medicine, University of Oxford, Roosevelt Drive, Oxford OX3 7BN (United Kingdom); Owens, Raymond J., E-mail: ray@strubi.ox.ac.uk [The Oxford Protein Production Facility, Henry Wellcome Building for Genomic Medicine, University of Oxford, Roosevelt Drive, Oxford OX3 7BN (United Kingdom); Division of Structural Biology, Henry Wellcome Building for Genomic Medicine, University of Oxford, Roosevelt Drive, Oxford OX3 7BN (United Kingdom)

    2006-06-01

    The structure of the P{sub II} signal transduction protein of N. meningitidis at 1.85 Å resolution is described. The P{sub II} signal transduction proteins GlnB and GlnK are implicated in the regulation of nitrogen assimilation in Escherichia coli and other enteric bacteria. P{sub II}-like proteins are widely distributed in bacteria, archaea and plants. In contrast to other bacteria, Neisseria are limited to a single P{sub II} protein (NMB 1995), which shows a high level of sequence identity to GlnB and GlnK from Escherichia coli (73 and 62%, respectively). The structure of the P{sub II} protein from N. meningitidis (serotype B) has been solved by molecular replacement to a resolution of 1.85 Å. Comparison of the structure with those of other P{sub II} proteins shows that the overall fold is tightly conserved across the whole population of related proteins, in particular the positions of the residues implicated in ATP binding. It is proposed that the Neisseria P{sub II} protein shares functions with GlnB/GlnK of enteric bacteria.

  17. Nano-structured Ni(II)-curcumin modified glassy carbon electrode for electrocatalytic oxidation of fructose

    International Nuclear Information System (INIS)

    Elahi, M. Yousef; Mousavi, M.F.; Ghasemi, S.

    2008-01-01

    A nano-structured Ni(II)-curcumin (curcumin: 1,7-bis[4-hydroxy-3-methoxyphenyl]-1,6-heptadiene-3,5-dione) film is electrodeposited on a glassy carbon electrode in alkaline solution. The morphology of polyNi(II)-curcumin (NC) was investigated by scanning electron microscopy (SEM). The SEM results show NC has a nano-globular structure in the range 20-50 nm. Using cyclic voltammetry, linear sweep voltammetry, chronoamperometry, steady-state polarization measurements and electrochemical impedance spectroscopy (EIS) showed that the nano-structure NC film acts as an efficient material for the electrocatalytic oxidation of fructose. According to the voltammetric studies, the increase in the anodic peak current and subsequent decrease in the corresponding cathodic current, fructose was oxidized on the electrode surface via an electrocatalytic mechanism. The EIS results show that the charge-transfer resistance has as a function of fructose concentration, time interval and applied potential. The increase in the fructose concentration and time interval in fructose solution results in enhanced charge transfer resistance in Nyquist plots. The EIS results indicate that fructose electrooxidation at various potentials shows different impedance behaviors. At lower potentials, a semicircle is observed in the first quadrant of impedance plot. With further increase of the potential, a transition of the semicircle from the first to the second quadrant occurs. Also, the results obtained show that the rate of fructose electrooxidation depends on concentration of OH - . Electron transfer coefficient, diffusion coefficient and rate constant of the electrocatalytic oxidation reaction are obtained. The modified electrode was used as a sensor for determination of fructose with a good dynamic range and a low detection limit

  18. Trapping and Probing Antihydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Wurtele, Jonathan [UC Berkeley and LBNL

    2013-03-27

    Precision spectroscopy of antihydrogen is a promising path to sensitive tests of CPT symmetry. The most direct route to achieve this goal is to create and probe antihydrogen in a magnetic minimum trap. Antihydrogen has been synthesized and trapped for 1000s at CERN by the ALPHA Collaboration. Some of the challenges associated with achieving these milestones will be discussed, including mixing cryogenic positron and antiproton plasmas to synthesize antihydrogen with kinetic energy less than the trap potential of .5K. Recent experiments in which hyperfine transitions were resonantly induced with microwaves will be presented. The opportunity for gravitational measurements in traps based on detailed studies of antihydrogen dynamics will be described. The talk will conclude with a discussion future antihydrogen research that will use a new experimental apparatus, ALPHA-I.

  19. EBIT trapping program

    International Nuclear Information System (INIS)

    Elliott, S.R.; Beck, B.; Beiersdorfer, P.; Church, D.; DeWitt, D.; Knapp, D.K.; Marrs, R.E.; Schneider, D.; Schweikhard, L.

    1993-01-01

    The LLNL electron beam ion trap provides the world's only source of stationary highly charged ions up to bare U. This unique capability makes many new atomic and nuclear physics experiments possible. (orig.)

  20. Two interpenetrating Cu{sup II}/Ni{sup II}-coordinated polymers based on an unsymmetrical bifunctional N/O-tectonic: Syntheses, structures and magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yong-Liang [College of Materials & Chemical Engineering, China Three Gorges University, Yichang 443002 (China); Department of Chemistry and Chemical Engineering, Shaanxi Key Laboratory of Comprehensive Utilization of Tailings Resources, Shang Luo University, Shang Luo 726000 (China); Wu, Ya-Pan [College of Materials & Chemical Engineering, China Three Gorges University, Yichang 443002 (China); Li, Dong-Sheng, E-mail: lidongsheng1@126.com [College of Materials & Chemical Engineering, China Three Gorges University, Yichang 443002 (China); Dong, Wen-Wen [College of Materials & Chemical Engineering, China Three Gorges University, Yichang 443002 (China); Zhou, Chun-Sheng [Department of Chemistry and Chemical Engineering, Shaanxi Key Laboratory of Comprehensive Utilization of Tailings Resources, Shang Luo University, Shang Luo 726000 (China)

    2015-03-15

    Two new interpenetrating Cu{sup II}/Ni{sup II} coordination polymers, based on a unsymmetrical bifunctional N/O-tectonic 3-(pyrid-4′-yl)-5-(4″-carbonylphenyl)-1,2,4-triazolyl (H{sub 2}pycz), ([Cu-(Hpycz){sub 2}]·2H{sub 2}O){sub n} (1) and ([Ni(Hpycz){sub 2}]·H{sub 2}O){sub n} (2), have been solvothermally synthesized and structure characterization. Single crystal X-ray analysis indicates that compound 1 shows 2-fold parallel interpenetrated 4{sup 4}-sql layers with the same handedness. The overall structure of 1 is achiral—in each layer of doubly interpenetrating nets, the two individual nets have the opposite handedness to the corresponding nets in the adjoining layers—while 2 features a rare 8-fold interpenetrating 6{sup 6}-dia network that belongs to class IIIa interpenetration. In addition, compounds 1 and 2 both show similar paramagnetic characteristic properties. - Graphical abstract: Two new Cu(II)/Ni(II) coordination polymers present 2D parallel 2-fold interpenetrated 4{sup 4}-sql layers and a rare 3D 8-fold interpenetrating 6{sup 6}-dia network. In addition, magnetic susceptibility measurements show similar paramagnetic characteristic for two complexes. - Highlights: • A new unsymmetrical bifunctional N/O-tectonic as 4-connected spacer. • A 2-fold parallel interpenetrated sql layer with the same handedness. • A rare 8-fold interpenetrating dia network (class IIIa)

  1. Crystal structure of myotoxin-II: a myotoxic phospholipase A2 - homologue from Bothrops moojeni venom

    International Nuclear Information System (INIS)

    Azevedo, W.F.; Ward, R.J.; Lombardi, F.R.; Arni, R.K.; Soares, A.M.; Giglio, J.R.; Fontes, M.R.M.

    1997-01-01

    Full text. Phospho lipases A2 (PLA 2 ; E C 3.1.1.4, phosphatides s n-2 acyl hydrolases) hydrolysis the s n-2 ester bond of phospholipids showing enhanced activity at lamellar or membrane surfaces. Intracellular PLA 2 s are involved at phospholipid metabolism and signal transduction, whereas extracellular PLA 2 s are found in mammalian pancreatic juices, the venoms of snakes, lizards and insects. Based on their high primary sequence similarity, extracellular PLA 2 s are separated into Classes I, II and III. Class II PLA 2 s are found in snake venoms of Crotalidae an Viperidae species, and include the sub-family of Lys PLA 2 s homologue. he coordination of the Ca 2+ ion in the PLA 2 calcium-binding loop includes and aspartate at position 49. In the catalytically active PLA 2 s, this calcium ion plays a critical role in the stabilization of the tetrahedral transition state intermediate in the catalytic mechanism. The conservative substitution Asp49-Lys results in a decreased calcium affinity with a concomitant loss of catalytic activity, and naturally occurring PLA 2 s-homologues showing the same substitution are catalytically inactive. However, the Lys PLA 2 s possess cytolytic and myotoxic activities and furthermore retain the ability to disrupt the integrity of both plasma membranes and model lipid layers by a ca 2+ -independent mechanism for which there is no evidence of lipid hydrolysis. Lys 49 PLA 2 homologues have been isolated from several Bothrops spp. venoms including B. moojeni. Therefore, in order to improve our understanding of the molecular basis of the myotoxic and Ca 2+ independent membrane damaging activities we have determined the crystal structure of MjTX-II, a Lys 49 homologue from the venom of B. moojeni. The model presented has been determined at 2.0 A resolution and refined to a crystallographic residual of 19.7% (R f ree=28.1%). (author)

  2. Innovation: the classic traps.

    Science.gov (United States)

    Kanter, Rosabeth Moss

    2006-11-01

    Never a fad, but always in or out of fashion, innovation gets rediscovered as a growth enabler every half dozen years. Too often, though, grand declarations about innovation are followed by mediocre execution that produces anemic results, and innovation groups are quietly disbanded in cost-cutting drives. Each managerial generation embarks on the same enthusiastic quest for the next new thing. And each generation faces the same vexing challenges- most of which stem from the tensions between protecting existing revenue streams critical to current success and supporting new concepts that may be crucial to future success. In this article, Harvard Business School professor Rosabeth Moss Kanter reflects on the four major waves of innovation enthusiasm she's observed over the past 25 years. She describes the classic mistakes companies make in innovation strategy, process, structure, and skills assessment, illustrating her points with a plethora of real-world examples--including AT&T Worldnet, Timberland, and Ocean Spray. A typical strategic blunder is when managers set their hurdles too high or limit the scope of their innovation efforts. Quaker Oats, for instance, was so busy in the 1990s making minor tweaks to its product formulas that it missed larger opportunities in distribution. A common process mistake is when managers strangle innovation efforts with the same rigid planning, budgeting, and reviewing approaches they use in their existing businesses--thereby discouraging people from adapting as circumstances warrant. Companies must be careful how they structure fledgling entities alongside existing ones, Kanter says, to avoid a clash of cultures and agendas--which Arrow Electronics experienced in its attempts to create an online venture. Finally, companies commonly undervalue and underinvest in the human side of innovation--for instance, promoting individuals out of innovation teams long before their efforts can pay off. Kanter offers practical advice for avoiding

  3. Optical Trapping of Ion Coulomb Crystals

    Directory of Open Access Journals (Sweden)

    Julian Schmidt

    2018-05-01

    Full Text Available The electronic and motional degrees of freedom of trapped ions can be controlled and coherently coupled on the level of individual quanta. Assembling complex quantum systems ion by ion while keeping this unique level of control remains a challenging task. For many applications, linear chains of ions in conventional traps are ideally suited to address this problem. However, driven motion due to the magnetic or radio-frequency electric trapping fields sometimes limits the performance in one dimension and severely affects the extension to higher-dimensional systems. Here, we report on the trapping of multiple barium ions in a single-beam optical dipole trap without radio-frequency or additional magnetic fields. We study the persistence of order in ensembles of up to six ions within the optical trap, measure their temperature, and conclude that the ions form a linear chain, commonly called a one-dimensional Coulomb crystal. As a proof-of-concept demonstration, we access the collective motion and perform spectrometry of the normal modes in the optical trap. Our system provides a platform that is free of driven motion and combines advantages of optical trapping, such as state-dependent confinement and nanoscale potentials, with the desirable properties of crystals of trapped ions, such as long-range interactions featuring collective motion. Starting with small numbers of ions, it has been proposed that these properties would allow the experimental study of many-body physics and the onset of structural quantum phase transitions between one- and two-dimensional crystals.

  4. Search For Trapped Antihydrogen

    CERN Document Server

    Andresen, Gorm B.; Baquero-Ruiz, Marcelo; Bertsche, William; Bowe, Paul D.; Bray, Crystal C.; Butler, Eoin; Cesar, Claudio L.; Chapman, Steven; Charlton, Michael; Fajans, Joel; Friesen, Tim; Fujiwara, Makoto C.; Gill, David R.; Hangst, Jeffrey S.; Hardy, Walter N.; Hayano, Ryugo S.; Hayden, Michael E.; Humphries, Andrew J.; Hydomako, Richard; Jonsell, Svante; Jorgensen, Lars V.; Kurchaninov, Lenoid; Lambo, Ricardo; Madsen, Niels; Menary, Scott; Nolan, Paul; Olchanski, Konstantin; Olin, Art; Povilus, Alexander; Pusa, Petteri; Robicheaux, Francis; Sarid, Eli; Nasr, Sarah Seif El; Silveira, Daniel M.; So, Chukman; Storey, James W.; Thompson, Robert I.; van der Werf, Dirk P.; Wilding, Dean; Wurtele, Jonathan S.; Yamazaki, Yasunori

    2011-01-01

    We present the results of an experiment to search for trapped antihydrogen atoms with the ALPHA antihydrogen trap at the CERN Antiproton Decelerator. Sensitive diagnostics of the temperatures, sizes, and densities of the trapped antiproton and positron plasmas have been developed, which in turn permitted development of techniques to precisely and reproducibly control the initial experimental parameters. The use of a position-sensitive annihilation vertex detector, together with the capability of controllably quenching the superconducting magnetic minimum trap, enabled us to carry out a high-sensitivity and low-background search for trapped synthesised antihydrogen atoms. We aim to identify the annihilations of antihydrogen atoms held for at least 130 ms in the trap before being released over ~30 ms. After a three-week experimental run in 2009 involving mixing of 10^7 antiprotons with 1.3 10^9 positrons to produce 6 10^5 antihydrogen atoms, we have identified six antiproton annihilation events that are consist...

  5. Scope Oriented Thermoeconomic analysis of energy systems. Part II: Formation Structure of Optimality for robust design

    International Nuclear Information System (INIS)

    Piacentino, Antonio; Cardona, Ennio

    2010-01-01

    This paper represents the Part II of a paper in two parts. In Part I the fundamentals of Scope Oriented Thermoeconomics have been introduced, showing a scarce potential for the cost accounting of existing plants; in this Part II the same concepts are applied to the optimization of a small set of design variables for a vapour compression chiller. The method overcomes the limit of most conventional optimization techniques, which are usually based on hermetic algorithms not enabling the energy analyst to recognize all the margins for improvement. The Scope Oriented Thermoeconomic optimization allows us to disassemble the optimization process, thus recognizing the Formation Structure of Optimality, i.e. the specific influence of any thermodynamic and economic parameter in the path toward the optimal design. Finally, the potential applications of such an in-depth understanding of the inner driving forces of the optimization are discussed in the paper, with a particular focus on the sensitivity analysis to the variation of energy and capital costs and on the actual operation-oriented design.

  6. A new zinc(II supramolecular square: Synthesis, crystal structure, thermal behavior and luminescence

    Directory of Open Access Journals (Sweden)

    Wang Xiu-Yan

    2015-01-01

    Full Text Available A new square-shaped Zn(II complex, namely, [Zn4(L4(phen4]•6H2O (1 (L = 2-hydroxynicotinate and phen = 1,10- phenanthroline, has been synthesized under hydrothermal condition. The crystal of 1 belongs to triclinic, space group P -1 with a = 10.773(2 Å, b = 12.641(3 Å, c = 13.573(3 Å, α = 107.44(3º, β = 102.66(3º, γ = 93.89(3°, C72H56N12O18Zn4, Mr = 1638.77, V = 1702.8(6 Å3 , Z = 1, Dc = 1.598 g/cm3 , S = 1.045, μ(MoKα = 1.475 mm-1 , F(000 = 836, R = 0.0472 and wR = 0.0919. In 1, four L ligands bridge four Zn(II atoms to form a square-shaped structure, where four phen ligands are respectively located on four corners of the square. The π-π stacking interactions extend the adjacent squares into a 1D supramolecular chain. The thermal behavior of 1 has been characterized. Moreover, its solid state luminescence property has been studied at room temperature.

  7. Magnetic oscillations and quasiparticle band structure in the mixed state of type-II superconductors

    International Nuclear Information System (INIS)

    Norman, M.R.; MacDonald, A.H.; Akera, H.

    1995-01-01

    We consider magnetic oscillations due to Landau quantization in the mixed state of type-II superconductors. Our work is based on a previously developed formalism which allows the mean-field gap equations of the Abrikosov state to be conveniently solved in a Landau-level representation. We find that the quasiparticle band structure changes qualitatively when the pairing self-energy becomes comparable to the Landau-level separation. For small pairing self-energies, Landau-level mixing due to the superconducting order is weak and magnetic oscillations survive in the superconducting state although they are damped. We find that the width of the quasiparticle Landau levels in this regime varies approximately as Δ 0 n μ -1/4 where Δ 0 is proportional to the magnitude of the order parameter and n μ is the Landau-level index at the Fermi energy. For larger pairing self-energies, the lowest energy quasiparticle bands occur in pairs which are nearly equally spaced from each other and evolve with weakening magnetic field toward the bound states of an isolated vortex core. These bands have a weak magnetic field dependence and magnetic oscillations vanish rapidly in this regime. We discuss recent observations of the de Haas--van Alphen effect in the mixed state of several type-II superconductors in light of our results

  8. Synthesis, structural characterization and cytotoxic activity of two new organoruthenium(II complexes

    Directory of Open Access Journals (Sweden)

    SANJA GRGURIC-SIPKA

    2008-06-01

    Full Text Available Two new p-cymene ruthenium(II complexes containing as additional ligands N-methylpiperazine ([(η6-p-cymeneRuCl2(CH3NH(CH24NH]PF6, complex 1 or vitamin K3-thiosemicarbazone ([(η6-p-cymeneRuCl2(K3tsc], complex 2 were synthesized starting from [(η6-p-cymene2RuCl2]2 and the corresponding ligand. The complexes were characterized by elemental analysis, IR, electronic absorption and NMR spectroscopy. The X-ray crystal structure determination of complex 1 revealed “piano-stool” geometry. The differences in the cytotoxic activity of the two complexes are discussed in terms of the ligand present.

  9. Crystal structure of bis{μ-2-[(dimethylaminomethyl]ferroceneselenolato}bis[chloridopalladium(II

    Directory of Open Access Journals (Sweden)

    Esther M. Takaluoma

    2014-10-01

    Full Text Available The dinuclear title compound, [PdCl{Se[(C5H5Fe(C5H32CH2N(CH32]}]2 was obtained by the reaction of [PdCl2(NCPh2] with 2-[(N,N′-dimethylaminomethyl]ferroceneselenolate and the crystals for the structure determination were grown from a mixture of THF and n-hexane. Both PdII atoms are coordinated by the bridging Se atoms and by the amino N atoms of the bidentate 2-[(N,N′-dimethylaminomethyl]ferroceneselenolate ligand, as well as by Cl atoms, and show a distorted square-planar coordination. The angle between the Pd—Se—Se planes of the two Pd atoms is 149.31 (3°. Weak Cl...H hydrogen bonds link the binuclear complexes into a three-dimensional network.

  10. Superconductivity in a copper(II)-based coordination polymer with perfect kagome structure

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Xing; Liu, Liyao; Xu, Wei; Zhu, Daoben [Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing (China); University of Chinese Academy of Sciences, Beijing (China); Zhang, Shuai [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing (China); Yu, Lei [Department of Chemistry, University of Kentucky, Lexington, KY (United States); Chen, Genfu [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing (China); University of Chinese Academy of Sciences, Beijing (China); Collaborative Innovation Center of Quantum Matter, Beijing (China)

    2018-01-02

    A highly crystalline copper(II) benzenehexathiolate coordination polymer (Cu-BHT) has been prepared. The two-dimensional kagome structure has been confirmed by powder X-ray diffraction, high-resolution transmission electron microscopy, and high-resolution scanning transmission electron microscopy. The as-prepared sample exhibits bulk superconductivity at about 0.25 K, which is confirmed by the zero resistivity, AC magnetic susceptibility, and specific heat measurements. Another diamagnetic transition at about 3 K suggests that there is a second superconducting phase that may be associated with a single layer or few layers of Cu-BHT. It is the first time that superconductivity has been observed in a coordination polymer. (copyright 2018 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. Structure of diphosphine complexes of Co(II) in solutions of organic compounds

    International Nuclear Information System (INIS)

    Saraev, V.V.; Mandyuk, I.M.; Ratovskii, G.V.; Dmitrieva, T.V.; Shmidt, F.K.

    1987-01-01

    The structure of the dichloride complexes of cobalt(II) with 1,2-bis(diphenylphosphino)ethane (DPPE) and 1,1-bis(diphenylphosphino)methane (DPPM) in organic solvents has been investigated by ESR and electronic spectroscopy. It has been shown that the low-spin complex Co(DPPE) 2 Cl 2 exists in dichloroethane and ethanol solutions in the form of a trigonal bipyramid. Cobalt dichloride reacts with DPPM to form 1:1 and 1:2 complexes, between which there is an equilibrium in a dichloroethane solution. The equilibrium is displaced under the action of the free diphosphine toward the formation of the 1:2 complex. Elimination of the diphosphine from the coordination sphere of cobalt occurs in an ethanol solution

  12. Crystal structure of dichloridobis(N,N′-dimethylthiourea-κSmercury(II

    Directory of Open Access Journals (Sweden)

    Muhammad Ashraf Shaheen

    2015-09-01

    Full Text Available The molecular structure of the title compound, [HgCl2(C3H8N2S2], has point group symmetry 2, with the twofold rotation axis passing through the HgII atom. The latter is coordinated by two Cl atoms and two N,N′-dimethylthiourea (Dmtu ligands through their S atoms, defining a distorted tetrahedral coordination sphere with bond angles in the range 102.47 (4–118.32 (4°. Intra- and intermolecular hydrogen bonds of the type N—H...Cl with S(6 and R22(12 ring motifs are present. The intermolecular contacts make up polymeric chains extending parallel to [101].

  13. Electronic band structures and optical properties of type-II superlattice photodetectors with interfacial effect.

    Science.gov (United States)

    Qiao, Peng-Fei; Mou, Shin; Chuang, Shun Lien

    2012-01-30

    The electronic band structures and optical properties of type-II superlattice (T2SL) photodetectors in the mid-infrared (IR) range are investigated. We formulate a rigorous band structure model using the 8-band k · p method to include the conduction and valence band mixing. After solving the 8 × 8 Hamiltonian and deriving explicitly the new momentum matrix elements in terms of envelope functions, optical transition rates are obtained through the Fermi's golden rule under various doping and injection conditions. Optical measurements on T2SL photodetectors are compared with our model and show good agreement. Our modeling results of quantum structures connect directly to the device-level design and simulation. The predicted doping effect is readily applicable to the optimization of photodetectors. We further include interfacial (IF) layers to study the significance of their effect. Optical properties of T2SLs are expected to have a large tunable range by controlling the thickness and material composition of the IF layers. Our model provides an efficient tool for the designs of novel photodetectors.

  14. Magneto-structural correlations in trinuclear Cu(II) complexes: a density functional study

    CERN Document Server

    Rodríguez-Forteá, A; Alvarez, S; Centre-De Recera-En-Quimica-Teorica; Alemany, P A; Centre-De Recera-En-Quimica-Teorica

    2003-01-01

    Density functional theoretical methods have been used to study magneto-structural correlations for linear trinuclear hydroxo-bridged copper(II) complexes. The nearest-neighbor exchange coupling constant shows very similar trends to those found earlier for dinuclear compounds for which the Cu-O-Cu angle and the out of plane displacement of the hydrogen atoms at the bridge are the two key structural factors that determine the nature of their magnetic behavior. Changes in these two parameters can induce variations of over 1000 cm sup - sup 1 in the value of the nearest-neighbor coupling constant. On the contrary, coupling between next-nearest neighbors is found to be practically independent of structural changes with a value for the coupling constant of about -60 cm sup - sup 1. The magnitude calculated for this coupling constant indicates that considering its value to be negligible, as usually done in experimental studies, can lead to considerable errors, especially for compounds in which the nearest-neighbor c...

  15. Novel Ion Trap Design for Strong Ion-Cavity Coupling

    Directory of Open Access Journals (Sweden)

    Alejandro Márquez Seco

    2016-04-01

    Full Text Available We present a novel ion trap design which facilitates the integration of an optical fiber cavity into the trap structure. The optical fibers are confined inside hollow electrodes in such a way that tight shielding and free movement of the fibers are simultaneously achievable. The latter enables in situ optimization of the overlap between the trapped ions and the cavity field. Through numerical simulations, we systematically analyze the effects of the electrode geometry on the trapping characteristics such as trap depths, secular frequencies and the optical access angle. Additionally, we simulate the effects of the presence of the fibers and confirm the robustness of the trapping potential. Based on these simulations and other technical considerations, we devise a practical trap configuration that isviable to achieve strong coupling of a single ion.

  16. HPLC-ESR techniques for detection of complex trapped radicals

    International Nuclear Information System (INIS)

    Tu Tiecheng; Dong Jirong; Lin Nianyun; Xie Leidong; Liu Rengzhong

    1992-01-01

    High performance liquid chromatography (HPLC) and ESR combined examination of radical species is an advanced techniques for separation and identification of complex radical species. At SRCL, Waters 990 HPLC has been used to separate the complex trapped radicals and Varian E-112 ESR spectrometer to record the spectra of single trapped radicals after HPLC separation. The advantages of the combined techniques are described as bellow: HPLC is used to separate the long-lived complex trapped radicals derived from reaction of short-lived radicals with spin trap. ESR spectra from single trapped radicals, obtained following HPLC separation of complex trapped radicals, are recorded one by one and well resolved. The structures of short-lived radicals can be inferred from the ESR spectra of the long-lived trapped radicals

  17. Investigation of non-corrin cobalt(II)-containing sites in protein structures of the Protein Data Bank.

    Science.gov (United States)

    Abriata, Luciano Andres

    2013-04-01

    Protein X-ray structures with non-corrin cobalt(II)-containing sites, either natural or substituting another native ion, were downloaded from the Protein Data Bank and explored to (i) describe which amino acids are involved in their first ligand shells and (ii) analyze cobalt(II)-donor bond lengths in comparison with previously reported target distances, CSD data and EXAFS data. The set of amino acids involved in Co(II) binding is similar to that observed for catalytic Zn(II) sites, i.e. with a large fraction of carboxylate O atoms from aspartate and glutamate and aromatic N atoms from histidine. The computed Co(II)-donor bond lengths were found to depend strongly on structure resolution, an artifact previously detected for other metal-donor distances. Small corrections are suggested for the target bond lengths to the aromatic N atoms of histidines and the O atoms of water and hydroxide. The available target distance for cysteine (Scys) is confirmed; those for backbone O and other donors remain uncertain and should be handled with caution in refinement and modeling protocols. Finally, a relationship between both Co(II)-O bond lengths in bidentate carboxylates is quantified.

  18. Trapping Dust to Form Planets

    Science.gov (United States)

    Kohler, Susanna

    2017-10-01

    Growing a planet from a dust grain is hard work! A new study explores how vortices in protoplanetary disks can assist this process.When Dust Growth FailsTop: ALMA image of the protoplanetary disk of V1247 Orionis, with different emission components labeled. Bottom: Synthetic image constructed from the best-fit model. [Kraus et al. 2017]Gradual accretion onto a seed particle seems like a reasonable way to grow a planet from a grain of dust; after all, planetary embryos orbit within dusty protoplanetary disks, which provides them with plenty of fuel to accrete so they can grow. Theres a challenge to this picture, though: the radial drift problem.The radial drift problem acknowledges that, as growing dust grains orbit within the disk, the drag force on them continues to grow as well. For large enough dust grains perhaps around 1 millimeter the drag force will cause the grains orbits to decay, and the particles drift into the star before they are able to grow into planetesimals and planets.A Close-Up Look with ALMASo how do we overcome the radial drift problem in order to form planets? A commonly proposed mechanism is dust trapping, in which long-lived vortices in the disk trap the dust particles, preventing them from falling inwards. This allows the particles to persist for millions of years long enough to grow beyond the radial drift barrier.Observationally, these dust-trapping vortices should have signatures: we would expect to see, at millimeter wavelengths, specific bright, asymmetric structures where the trapping occurs in protoplanetary disks. Such disk structures have been difficult to spot with past instrumentation, but the Atacama Large Millimeter/submillimeter Array (ALMA) has made some new observations of the disk V1247 Orionis that might be just what were looking for.Schematic of the authors model for the disk of V1247 Orionis. [Kraus et al. 2017]Trapped in a Vortex?ALMAs observations of V1247 Orionis are reported by a team of scientists led by Stefan

  19. Parameter Screening in Microfluidics Based Hydrodynamic Single-Cell Trapping

    Directory of Open Access Journals (Sweden)

    B. Deng

    2014-01-01

    Full Text Available Microfluidic cell-based arraying technology is widely used in the field of single-cell analysis. However, among developed devices, there is a compromise between cellular loading efficiencies and trapped cell densities, which deserves further analysis and optimization. To address this issue, the cell trapping efficiency of a microfluidic device with two parallel micro channels interconnected with cellular trapping sites was studied in this paper. By regulating channel inlet and outlet status, the microfluidic trapping structure can mimic key functioning units of previously reported devices. Numerical simulations were used to model this cellular trapping structure, quantifying the effects of channel on/off status and trapping structure geometries on the cellular trapping efficiency. Furthermore, the microfluidic device was fabricated based on conventional microfabrication and the cellular trapping efficiency was quantified in experiments. Experimental results showed that, besides geometry parameters, cellular travelling velocities and sizes also affected the single-cell trapping efficiency. By fine tuning parameters, more than 95% of trapping sites were taken by individual cells. This study may lay foundation in further studies of single-cell positioning in microfluidics and push forward the study of single-cell analysis.

  20. Structural and bioinformatic characterization of an Acinetobacter baumannii type II carrier protein

    International Nuclear Information System (INIS)

    Allen, C. Leigh; Gulick, Andrew M.

    2014-01-01

    The high-resolution crystal structure of a free-standing carrier protein from Acinetobacter baumannii that belongs to a larger NRPS-containing operon, encoded by the ABBFA-003406–ABBFA-003399 genes of A. baumannii strain AB307-0294, that has been implicated in A. baumannii motility, quorum sensing and biofilm formation, is presented. Microorganisms produce a variety of natural products via secondary metabolic biosynthetic pathways. Two of these types of synthetic systems, the nonribosomal peptide synthetases (NRPSs) and polyketide synthases (PKSs), use large modular enzymes containing multiple catalytic domains in a single protein. These multidomain enzymes use an integrated carrier protein domain to transport the growing, covalently bound natural product to the neighboring catalytic domains for each step in the synthesis. Interestingly, some PKS and NRPS clusters contain free-standing domains that interact intermolecularly with other proteins. Being expressed outside the architecture of a multi-domain protein, these so-called type II proteins present challenges to understand the precise role they play. Additional structures of individual and multi-domain components of the NRPS enzymes will therefore provide a better understanding of the features that govern the domain interactions in these interesting enzyme systems. The high-resolution crystal structure of a free-standing carrier protein from Acinetobacter baumannii that belongs to a larger NRPS-containing operon, encoded by the ABBFA-003406–ABBFA-003399 genes of A. baumannii strain AB307-0294, that has been implicated in A. baumannii motility, quorum sensing and biofilm formation, is presented here. Comparison with the closest structural homologs of other carrier proteins identifies the requirements for a conserved glycine residue and additional important sequence and structural requirements within the regions that interact with partner proteins

  1. Structural and bioinformatic characterization of an Acinetobacter baumannii type II carrier protein

    Energy Technology Data Exchange (ETDEWEB)

    Allen, C. Leigh; Gulick, Andrew M., E-mail: gulick@hwi.buffalo.edu [University at Buffalo, Buffalo, NY 14203 (United States)

    2014-06-01

    The high-resolution crystal structure of a free-standing carrier protein from Acinetobacter baumannii that belongs to a larger NRPS-containing operon, encoded by the ABBFA-003406–ABBFA-003399 genes of A. baumannii strain AB307-0294, that has been implicated in A. baumannii motility, quorum sensing and biofilm formation, is presented. Microorganisms produce a variety of natural products via secondary metabolic biosynthetic pathways. Two of these types of synthetic systems, the nonribosomal peptide synthetases (NRPSs) and polyketide synthases (PKSs), use large modular enzymes containing multiple catalytic domains in a single protein. These multidomain enzymes use an integrated carrier protein domain to transport the growing, covalently bound natural product to the neighboring catalytic domains for each step in the synthesis. Interestingly, some PKS and NRPS clusters contain free-standing domains that interact intermolecularly with other proteins. Being expressed outside the architecture of a multi-domain protein, these so-called type II proteins present challenges to understand the precise role they play. Additional structures of individual and multi-domain components of the NRPS enzymes will therefore provide a better understanding of the features that govern the domain interactions in these interesting enzyme systems. The high-resolution crystal structure of a free-standing carrier protein from Acinetobacter baumannii that belongs to a larger NRPS-containing operon, encoded by the ABBFA-003406–ABBFA-003399 genes of A. baumannii strain AB307-0294, that has been implicated in A. baumannii motility, quorum sensing and biofilm formation, is presented here. Comparison with the closest structural homologs of other carrier proteins identifies the requirements for a conserved glycine residue and additional important sequence and structural requirements within the regions that interact with partner proteins.

  2. Atom exchange between aqueous Fe(II) and structural Fe in clay minerals.

    Science.gov (United States)

    Neumann, Anke; Wu, Lingling; Li, Weiqiang; Beard, Brian L; Johnson, Clark M; Rosso, Kevin M; Frierdich, Andrew J; Scherer, Michelle M

    2015-03-03

    Due to their stability toward reductive dissolution, Fe-bearing clay minerals are viewed as a renewable source of Fe redox activity in diverse environments. Recent findings of interfacial electron transfer between aqueous Fe(II) and structural Fe in clay minerals and electron conduction in octahedral sheets of nontronite, however, raise the question whether Fe interaction with clay minerals is more dynamic than previously thought. Here, we use an enriched isotope tracer approach to simultaneously trace Fe atom movement from the aqueous phase to the solid ((57)Fe) and from the solid into the aqueous phase ((56)Fe). Over 6 months, we observed a significant decrease in aqueous (57)Fe isotope fraction, with a fast initial decrease which slowed after 3 days and stabilized after about 50 days. For the aqueous (56)Fe isotope fraction, we observed a similar but opposite trend, indicating that Fe atom movement had occurred in both directions: from the aqueous phase into the solid and from the solid into aqueous phase. We calculated that 5-20% of structural Fe in clay minerals NAu-1, NAu-2, and SWa-1 exchanged with aqueous Fe(II), which significantly exceeds the Fe atom layer exposed directly to solution. Calculations based on electron-hopping rates in nontronite suggest that the bulk conduction mechanism previously demonstrated for hematite1 and suggested as an explanation for the significant Fe atom exchange observed in goethite2 may be a plausible mechanism for Fe atom exchange in Fe-bearing clay minerals. Our finding of 5-20% Fe atom exchange in clay minerals indicates that we need to rethink how Fe mobility affects the macroscopic properties of Fe-bearing phyllosilicates and its role in Fe biogeochemical cycling, as well as its use in a variety of engineered applications, such as landfill liners and nuclear repositories.

  3. Effects of citrate on hexavalent chromium reduction by structural Fe(II) in nontronite

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xiaolei; Dong, Hailiang; Yang, Xuewei; Kovarik, Libor; Chen, Yu; Zeng, Qiang

    2018-02-01

    Iron-bearing clay minerals and organic matter are two important components in natural environments that influence hexavalent chromium (Cr(VI)) reduction. Previous studies have shown that organic ligands could influence Cr(VI) reduction by aqueous Fe2+ and pyrite. However, the effects of organic ligands on Cr(VI) reduction by structural Fe(II) in clays are not well understood. In this study, the effects of citrate on Cr(VI) reduction by nontronite (NAu-2) were investigated under near neutral pH condition (pH=6). Our results showed that the presence of citrate decreased the rate but increased the amount of Cr(VI) reduction by structural Fe(II) in NAu-2. The decreased reaction rate was likely due to competitive sorption of citrate and polyanionic dichromate (Cr2O7- ), because sorption of dichromate appeared to be the first step for subsequent Cr(VI) reduction. The increased amount of Cr(VI) reduction in the presence of citrate was likely because citrate provided additional reducing power through ligand-metal electron transfer in the presence of soluble Fe 3+ derived from dissolution of reduced NAu-2. Soluble Cr(III)-citrate complex was the possible form of reduced chromium when citrate was present. In contrast, nanometer-sized Cr2O3 particles were the product of Cr(VI) reduction by reduced NAu-2 without citrate. Our study highlights the importance of organic ligands on Cr(VI) reduction and immobilization when iron-bearing clay minerals are applied to treat Cr(VI) contaminant in organic matter rich environments.

  4. Controlling trapping potentials and stray electric fields in a microfabricated ion trap through design and compensation

    International Nuclear Information System (INIS)

    Charles Doret, S; Amini, Jason M; Wright, Kenneth; Volin, Curtis; Killian, Tyler; Ozakin, Arkadas; Denison, Douglas; Hayden, Harley; Pai, C-S; Slusher, Richart E; Harter, Alexa W

    2012-01-01

    Recent advances in quantum information processing with trapped ions have demonstrated the need for new ion trap architectures capable of holding and manipulating chains of many (>10) ions. Here we present the design and detailed characterization of a new linear trap, microfabricated with scalable complementary metal-oxide-semiconductor (CMOS) techniques, that is well-suited to this challenge. Forty-four individually controlled dc electrodes provide the many degrees of freedom required to construct anharmonic potential wells, shuttle ions, merge and split ion chains, precisely tune secular mode frequencies, and adjust the orientation of trap axes. Microfabricated capacitors on dc electrodes suppress radio-frequency pickup and excess micromotion, while a top-level ground layer simplifies modeling of electric fields and protects trap structures underneath. A localized aperture in the substrate provides access to the trapping region from an oven below, permitting deterministic loading of particular isotopic/elemental sequences via species-selective photoionization. The shapes of the aperture and radio-frequency electrodes are optimized to minimize perturbation of the trapping pseudopotential. Laboratory experiments verify simulated potentials and characterize trapping lifetimes, stray electric fields, and ion heating rates, while measurement and cancellation of spatially-varying stray electric fields permits the formation of nearly-equally spaced ion chains. (paper)

  5. Two new Zn(II) and Cd(II) coordinastion polymers based on amino-tetrazole and phenylcarboxylate: Syntheses, topological structures and photoluminescent properties

    International Nuclear Information System (INIS)

    Liu, Dong-Sheng; Sui, Yan; Chen, Weng-Tong; Huang, Jian-Gen; Chen, Jian-Zhong; Huang, Chang-Cang

    2012-01-01

    Two Zn(II) and Cd(II) compounds with the in-situ generated ligand of 5-amino-tetrazolate (atz − ) were prepared from the hydrothermal reactions of the corresponding Cd or Zn(II) salts with phenylcarboxylate, and characterized by elemental analysis, IR spectroscopy, and TGA. The results of X-ray crystallographic analysis reveal that compound [Zn 2 (BZA)(atz) 2 (OH)] n (1) (BZA=benzoic acid) presents a two-dimensional (2D) “hcb” topological network constructed from the ZnN 2 O 2 tetrahedra. In compound [Cd 6 (atz) 6 (PTA) 3 ] n (2) (PTA=terephthalic acid), the identical [Cd 3 (atz) 3 )] 3+ n clusters are connected by atz ligands to generate a 2D cationic layer, and the neighboring cationic layers are pillared by PTA giving birth to 3D network. After simplifying, the complicated 3D network of 2 can be presented as an unprecedented (4, 4, 10)-connected trinodal topology. The formations of the structures show a good example that using the combination of the in-situ generated ligand and other coligand synthetic strategy can construct interesting topological structures. The thermal stabilities and fluorescent properties of the complexes have also been studied. - Graphical abstract: Two d 10 metal complexes have been synthesized by employing mixed-ligand synthetic approach. Complex 1 presents a 2D “hcb” topological network. Complex 2 shows an unprecedented (4, 4, 10)-connected trinodal topology. Highlights: ► Coligand synthetic strategy was applied to obtain new MOFs with useful properties. ► Two new Zn(II) and Cd(II) complexes were constructed from the mixed-ligand. ► Topologically, compound 2 presented an unprecedented (4, 4, 10)-connected trinodal topology. ► The two compounds may be excellent candidates for potential photoactive material.

  6. Biases in Drosophila melanogaster protein trap screens

    Directory of Open Access Journals (Sweden)

    Müller Ilka

    2009-05-01

    Full Text Available Abstract Background The ability to localise or follow endogenous proteins in real time in vivo is of tremendous utility for cell biology or systems biology studies. Protein trap screens utilise the random genomic insertion of a transposon-borne artificial reporter exon (e.g. encoding the green fluorescent protein, GFP into an intron of an endogenous gene to generate a fluorescent fusion protein. Despite recent efforts aimed at achieving comprehensive coverage of the genes encoded in the Drosophila genome, the repertoire of genes that yield protein traps is still small. Results We analysed the collection of available protein trap lines in Drosophila melanogaster and identified potential biases that are likely to restrict genome coverage in protein trap screens. The protein trap screens investigated here primarily used P-element vectors and thus exhibit some of the same positional biases associated with this transposon that are evident from the comprehensive Drosophila Gene Disruption Project. We further found that protein trap target genes usually exhibit broad and persistent expression during embryonic development, which is likely to facilitate better detection. In addition, we investigated the likely influence of the GFP exon on host protein structure and found that protein trap insertions have a significant bias for exon-exon boundaries that encode disordered protein regions. 38.8% of GFP insertions land in disordered protein regions compared with only 23.4% in the case of non-trapping P-element insertions landing in coding sequence introns (p -4. Interestingly, even in cases where protein domains are predicted, protein trap insertions frequently occur in regions encoding surface exposed areas that are likely to be functionally neutral. Considering the various biases observed, we predict that less than one third of intron-containing genes are likely to be amenable to trapping by the existing methods. Conclusion Our analyses suggest that the

  7. Accurate measurements of visible M1 transitions of titanium-like ions using an electron beam ion trap

    International Nuclear Information System (INIS)

    Crosby, D.N.; Gaarde-Widdowson, K.; Silver, J.D.; Tarbutt, M.R.

    2001-01-01

    Magnetic dipole transitions between the fine structure levels (3d 4 ) 5 D 3 - 5 D 2 of titanium-like silver and tin have been observed as emission lines from the Oxford electron beam ion trap (EBIT). The precision of the measurement system is validated by observation and comparison of well known lines in Kr II and He I with the database values, justifying uncertainties of 4-12 ppm. (orig.)

  8. Accurate measurements of visible M1 transitions of titanium-like ions using an electron beam ion trap

    Energy Technology Data Exchange (ETDEWEB)

    Crosby, D.N.; Gaarde-Widdowson, K.; Silver, J.D.; Tarbutt, M.R. [Oxford Univ. (United Kingdom). Dept. of Physics

    2001-07-01

    Magnetic dipole transitions between the fine structure levels (3d{sup 4}) {sup 5}D{sub 3}-{sup 5}D{sub 2} of titanium-like silver and tin have been observed as emission lines from the Oxford electron beam ion trap (EBIT). The precision of the measurement system is validated by observation and comparison of well known lines in Kr II and He I with the database values, justifying uncertainties of 4-12 ppm. (orig.)

  9. Co(II) and Cd(II) Complexes Derived from Heterocyclic Schiff-Bases: Synthesis, Structural Characterisation, and Biological Activity

    Science.gov (United States)

    Ahmed, Riyadh M.; Yousif, Enaam I.; Al-Jeboori, Mohamad J.

    2013-01-01

    New monomeric cobalt and cadmium complexes with Schiff-bases, namely, N′-[(E)-(3-hydroxy-4-methoxyphenyl)methylidene]furan-2-carbohydrazide (L1) and N′-[(E)-(3-hydroxy-4-methoxyphenyl)methylidene]thiophene-2-carbohydrazide (L2) are reported. Schiff-base ligands L1 and L2 were derived from condensation of 3-hydroxy-4-methoxybenzaldehyde (iso-vanillin) with furan-2-carboxylic acid hydrazide and thiophene-2-carboxylic acid hydrazide, respectively. Complexes of the general formula [M(L)2]Cl2 (where M = Co(II) or Cd(II), L = L1 or L2) have been obtained from the reaction of the corresponding metal chloride with the ligands. The ligands and their metal complexes were characterised by spectroscopic methods (FTIR, UV-Vis, 1H, and 13C NMR spectra), elemental analysis, metal content, magnetic measurement, and conductance. These studies revealed the formation of four-coordinate complexes in which the geometry about metal ion is tetrahedral. Biological activity of the ligands and their metal complexes against gram positive bacterial strain Bacillus (G+) and gram negative bacteria Pseudomonas (G−) revealed that the metal complexes become less resistive to the microbial activities as compared to the free ligands. PMID:24027449

  10. High-fidelity operations in microfabricated surface ion traps

    Science.gov (United States)

    Maunz, Peter

    2017-04-01

    Trapped ion systems can be used to implement quantum computation as well as quantum simulation. To scale these systems to the number of qubits required to solve interesting problems in quantum chemistry or solid state physics, the use of large multi-zone ion traps has been proposed. Microfabrication enables the realization of surface electrode ion traps with complex electrode structures. While these traps may enable the scaling of trapped ion quantum information processing (QIP), microfabricated ion traps also pose several technical challenges. Here, we present Sandia's trap fabrication capabilities and characterize trap properties and shuttling operations in our most recent high optical access trap (HOA-2). To demonstrate the viability of Sandia's microfabricated ion traps for QIP we realize robust single and two-qubit gates and characterize them using gate set tomography (GST). In this way we are able to demonstrate the first single qubit gates with a diamond norm of less than 1 . 7 ×10-4 , below a rigorous fault tolerance threshold for general noise of 6 . 7 ×10-4. Furthermore, we realize Mølmer-Sørensen two qubit gates with a process fidelity of 99 . 58(6) % also characterized by GST. These results demonstrate the viability of microfabricated surface traps for state of the art quantum information processing demonstrations. This research was funded, in part, by the Office of the Director of National Intelligence (ODNI), Intelligence Advanced Research Projects Activity (IARPA).

  11. Reaction of Pb(II) and Zn(II) with Ethyl Linoleate To Form Structured Hybrid Inorganic–Organic Complexes: A Model for Degradation in Historic Paint Films

    Energy Technology Data Exchange (ETDEWEB)

    MacDonald, Margaret G.; Palmer, Michael R.; Suchomel, Matthew R.; Berrie, Barbara H. (NGA); (Bordeaux)

    2016-09-23

    To investigate soap formation in drying oils in historic paints, the reaction between metal acetates (K+, Zn2+, Pb2+) and ethyl linoleate (EL) was studied using optical microscopy, X-ray powder diffraction, and electron microscopy. Pb(II) and Zn(II) react rapidly with EL to form highly structured, spherulitic, luminescent crystallites that aggregate. Evidence from Fourier transform infrared (FTIR) and scanning electron microscopy/energy dispersive X-ray analysis and high-resolution synchrotron powder X-ray diffraction indicates that these are organic–inorganic hybrid complexes or coordination polymers. FTIR absorbance peaks at ca. 1540 cm–1 for Pb(II) and ca. 1580 cm–1 for Zn(II) are consistent with the formation of carboxylate complexes. The complexes formed offer insight into the degradation processes observed in oil paint films, suggesting that soap formation is rapid when metal ions are solubilized and can occur with unsaturated fatty acids that are present in fresh oils. These complexes may account for the atypical luminescence observed in lead-containing cured oil paint films.

  12. Nickel(II) and copper(II) complexes of N,N-dialkyl-N‧-3-chlorobenzoylthiourea: Synthesis, characterization, crystal structures, Hirshfeld surfaces and antimicrobial activity

    Science.gov (United States)

    Binzet, Gun; Gumus, Ilkay; Dogen, Aylin; Flörke, Ulrich; Kulcu, Nevzat; Arslan, Hakan

    2018-06-01

    We synthesized four new N,N-dialkyl-N‧-3-chlorobenzoylthiourea ligands (Alkyl: Dimethyl, diethyl, di-n-propyl and di-n-butyl) and their metal complexes with copper and nickel atoms. The structure of all synthesized compounds was fully characterized by physicochemical, spectroscopic and single crystal X-ray diffraction analysis techniques. The physical, spectral and analytical data of the newly synthesized metal complexes have shown the formation of 1:2 (metal:ligand) ratio. The benzoylthiourea ligands coordinate with metal atoms through oxygen and sulphur atoms. The metal atoms are in slightly distorted square-planar coordination geometry in Ni(II) or Cu(II) complex. Two oxygen and two sulphur atoms are mutually cis to each other in Ni(II) or Cu(II) complex. The intermolecular contacts in the compounds, which are HL1 and HL3, were examined by Hirshfeld surfaces and fingerprint plots using the data obtained from X-ray single crystal diffraction measurement. Besides these, their antimicrobial activities against Gram-positive bacteria (Bacillus subtilis, Staphylococcus aureus, Streptococcus pyogenes and Enterococcus faecalis) and Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa) and anti-yeast activity (Candida glabrata, Candida parapsilosis and Candida albicans) were investigated. This exhibited some promising results towards testing organism. Among all the compounds, Ni(L1)2 complex showed high activity against Bacillus subtilis with MIC values at 7.81 μg/mL.

  13. Structure of the Hydrated Platinum(II) Ion And the Cis-Diammine-Platinum(II) Complex in Acidic Aqueous Solution: An EXAFS Study

    Energy Technology Data Exchange (ETDEWEB)

    Jalilehvand, F.; Laffin, L.J.

    2009-05-18

    Careful analysis of Pt L{sub 3}-edge extended X-ray absorption fine structure (EXAFS) spectra shows that the hydrated platinum(II) ion in acidic (HClO{sub 4}) aqueous solution binds four water molecules with the Pt-O bond distance 2.01(2) {angstrom} and one (or two) in the axial position at 2.39(2) {angstrom}. The weak axial water coordination is in accordance with the unexpectedly small activation volume previously reported for water exchange in an interchange mechanism with associative character. The hydrated cis-diammineplatinum(II) complex has a similar coordination environment with two ammine and two aqua ligands strongly bound with Pt-O/N bond distances of 2.01(2) {angstrom} and, in addition, one (or two) axial water molecule at 2.37(2) {angstrom}. This result provides a new basis for theoretical computational studies aiming to connect the function of the anticancer drug cis-platin to its ligand exchange reactions, where usually four-coordinated square planar platinum(II) species are considered as the reactant and product. {sup 195}Pt NMR spectroscopy has been used to characterize the Pt(II) complexes.

  14. Structural relationships among the multiple forms of DNA-dependent RNA polymerase II from cultured parsley cells

    International Nuclear Information System (INIS)

    Link, G.; Bogorad, L.; Kidd, G.H.; Richter, G.

    1978-01-01

    DNA-dependent RNA polymerase II (or B) was purified from cultured parsley cells, and its molecular structure was examined in detail. Upon centrifugation through glycerol gradients, RNA polymerase II sediments as a single band with an apparent sedimentation constant of 15S. No contamination with RNA polymerases I or III could be detected when the activity of purified RNA polymerase II was assayed in the presence of high concentrations of α-amanitin. Analysis of purified RNA polymerase II be nondenaturing and denaturing polyacrylamide gel electrophoresis revealed that this enzyme exists in multiple forms. They were designated II(O), II(A), and II(B). It is suggested that each form has a subunit of Mr = 140000 as well as smaller polypeptides in common. They differ, however, in the molecular weights of their largest subunits which is 220000 in form II(O), 200000 in form II(A), and 180000 in form II(B). These large subunits were labelled with 125 I, digested with trypsin, and tryptic digests were compared by two-dimensional analysis on thin-layer plates (Elder et al. (1977) J. Biol. Chem. 252, 6510-6515). Fingerprints of tryptic digests from the polypeptides with Mr = 220000, Mr = 200000, and Mr = 180000 were similar. It is, therefore, suggested that these subunits are stucturally related. A tryptic digest was also produced from the subunit with Mr = 140000. Its fingerprint was found to yield a considerably different distribution of peptides as compared to those from the three large subunits. (orig.) [de

  15. On the modular structure of the genus-one Type II superstring low energy expansion

    International Nuclear Information System (INIS)

    D’Hoker, Eric; Green, Michael B.; Vanhove, Pierre

    2015-01-01

    The analytic contribution to the low energy expansion of Type II string amplitudes at genus-one is a power series in space-time derivatives with coefficients that are determined by integrals of modular functions over the complex structure modulus of the world-sheet torus. These modular functions are associated with world-sheet vacuum Feynman diagrams and given by multiple sums over the discrete momenta on the torus. In this paper we exhibit exact differential and algebraic relations for a certain infinite class of such modular functions by showing that they satisfy Laplace eigenvalue equations with inhomogeneous terms that are polynomial in non-holomorphic Eisenstein series. Furthermore, we argue that the set of modular functions that contribute to the coefficients of interactions up to order D 10 R 4 are linear sums of functions in this class and quadratic polynomials in Eisenstein series and odd Riemann zeta values. Integration over the complex structure results in coefficients of the low energy expansion that are rational numbers multiplying monomials in odd Riemann zeta values.

  16. Impact of monovalent cations on soil structure. Part II. Results of two Swiss soils

    Science.gov (United States)

    Farahani, Elham; Emami, Hojat; Keller, Thomas

    2018-01-01

    In this study, we investigated the impact of adding solutions with different potassium and sodium concentrations on dispersible clay, water retention characteristics, air permeability, and soil shrinkage behaviour using two agricultural soils from Switzerland with different clay content but similar organic carbon to clay ratio. Three different solutions (including only Na, only K, and the combination of both) were added to soil samples at three different cation ratio of soil structural stability levels, and the soil samples were incubated for one month. Our findings showed that the amount of readily dispersible clay increased with increasing Na concentrations and with increasing cation ratio of soil structural stability. The treatment with the maximum Na concentration resulted in the highest water retention and in the lowest shrinkage capacity. This was was associated with high amounts of readily dispersible clay. Air permeability generally increased during incubation due to moderate wetting and drying cycles, but the increase was negatively correlated with readily dispersible clay. Readily dispersible clay decreased with increasing K, while readily dispersible clay increased with increasing K in Iranian soil (Part I of our study). This can be attributed to the different clay mineralogy of the studied soils (muscovite in Part I and illite in Part II).

  17. Testing and Analysis of a Composite Non-Cylindrical Aircraft Fuselage Structure . Part II; Severe Damage

    Science.gov (United States)

    Przekop, Adam; Jegley, Dawn C.; Lovejoy, Andrew E.; Rouse, Marshall; Wu, Hsi-Yung T.

    2016-01-01

    The Environmentally Responsible Aviation Project aimed to develop aircraft technologies enabling significant fuel burn and community noise reductions. Small incremental changes to the conventional metallic alloy-based 'tube and wing' configuration were not sufficient to achieve the desired metrics. One airframe concept identified by the project as having the potential to dramatically improve aircraft performance was a composite-based hybrid wing body configuration. Such a concept, however, presented inherent challenges stemming from, among other factors, the necessity to transfer wing loads through the entire center fuselage section which accommodates a pressurized cabin confined by flat or nearly flat panels. This paper discusses a finite element analysis and the testing of a large-scale hybrid wing body center section structure developed and constructed to demonstrate that the Pultruded Rod Stitched Efficient Unitized Structure concept can meet these challenging demands of the next generation airframes. Part II of the paper considers the final test to failure of the test article in the presence of an intentionally inflicted severe discrete source damage under the wing up-bending loading condition. Finite element analysis results are compared with measurements acquired during the test and demonstrate that the hybrid wing body test article was able to redistribute and support the required design loads in a severely damaged condition.

  18. On the modular structure of the genus-one Type II superstring low energy expansion

    Energy Technology Data Exchange (ETDEWEB)

    D’Hoker, Eric [Department of Physics and Astronomy,University of California, Los Angeles, CA 90095 (United States); Green, Michael B. [Department of Applied Mathematics and Theoretical Physics,Wilberforce Road, Cambridge CB3 0WA (United Kingdom); Vanhove, Pierre [Institut des Hautes Études Scientifiques, Le Bois-Marie, 35 route de Chartres,F-91440 Bures-sur-Yvette (France); Institut de physique théorique, Université Paris Saclay, CEA, CNRS,F-91191 Gif-sur-Yvette (France)

    2015-08-11

    The analytic contribution to the low energy expansion of Type II string amplitudes at genus-one is a power series in space-time derivatives with coefficients that are determined by integrals of modular functions over the complex structure modulus of the world-sheet torus. These modular functions are associated with world-sheet vacuum Feynman diagrams and given by multiple sums over the discrete momenta on the torus. In this paper we exhibit exact differential and algebraic relations for a certain infinite class of such modular functions by showing that they satisfy Laplace eigenvalue equations with inhomogeneous terms that are polynomial in non-holomorphic Eisenstein series. Furthermore, we argue that the set of modular functions that contribute to the coefficients of interactions up to order D{sup 10}R{sup 4} are linear sums of functions in this class and quadratic polynomials in Eisenstein series and odd Riemann zeta values. Integration over the complex structure results in coefficients of the low energy expansion that are rational numbers multiplying monomials in odd Riemann zeta values.

  19. Heysham II/Torness power stations: Seismic qualification of core structures and boilers

    International Nuclear Information System (INIS)

    Shepherd, D.J.

    1990-01-01

    For the advanced gas cooled reactors at Heysham II and Torness the seismic qualification of the core and support structures and boilers posed special problems. In each case the response was highly non-linear due to impacting. Within the core itself there are many thousands of degrees of freedom each dominated by impacting during the seismic event and these impact forces are transmitted to the support structure. The boilers, although supported and located in the design case by linear systems, have their motion during the seismic event controlled by seismic restraints and other components which introduce substantial impacting during seismic excitation. For both these important components a substantial programme of testing was carried out to validate an analysis approach. This testing and correlation with analysis is described in detail for both components. In the case of the core the qualification was based upon a non-linear code AGRCORE which was specifically developed to handle the large number of impact degrees of freedom for this component. The implementation of this code is also described together with a brief summary of results. The boiler analysis was ultimately carried out using conventional finite difference codes and the implementation of these together with a summary of results is also presented. (author). 13 figs, 1 tab

  20. Hydrothermal synthesis, crystal structures, and enantioselective adsorption property of bis(L-histidinato)nickel(II) monohydrate

    Science.gov (United States)

    Ramos, Christian Paul L.; Conato, Marlon T.

    2018-05-01

    Despite the numerous researches in metal-organic frameworks (MOFs), there are only few reports on biologically important amino acids, histidine in particular, on its use as bridging ligand in the construction of open-framework architectures. In this work, hydrothermal synthesis was used to prepare a compound based on Ni2+ and histidine. The coordination assembly of imidazole side chain of histidine with divalent nickel ions in aqueous condition yielded purple prismatic solids. Single crystal X-ray diffraction (XRD) analysis of the product revealed structure for Ni(C6H8N3O2)2 • H2O that has a monoclinic (C2) structure with lattice parameters, a = 29.41, b = 8.27, c = 6.31 Å, β = 90.01 ˚. Circular dichroism - optical rotatory dispersion (CD-ORD), Powder X-ray diffraction (PXRD) and Fourier transform - infrared spectroscopy (FT-IR) analyses are conducted to further characterize the crystals. Enantioselective adsorption analysis using racemic mixture of 2-butanol confirmed bis(L-histidinato)nickel(II) monohydrate MOF crystal's enantioselective property preferentially favoring the adsorption of (S)-2-butanol isomer.

  1. Crystal structures and thermodynamics/kinetics of Zn(II) coordination polymers with helical chains

    Energy Technology Data Exchange (ETDEWEB)

    He, Tian [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi’an 710069 (China); Yue, Ke-Fen, E-mail: ykflyy@nwu.edu.cn [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi’an 710069 (China); Zhao, Yi-xing; Chen, San-Ping [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi’an 710069 (China); Zhou, Chun-sheng, E-mail: slzhoucs@126.com.cn [Shaanxi Key Laboratory of Comprehensive Utilization of Tailings Resources, College of Chemical Engineering and Modern Materials, Shangluo University, Shangluo 726000 (China); Yan, Ni [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi’an 710069 (China)

    2016-07-15

    Solvothermal reactions of Zn(II) acetates and four V-shaped carboxylates ligands in the presence of 1,4-Bis(2-methyl-imidazol-1-yl)butane afforded four interesting Zn(II) coordination polymers with helical chains, namely, {[Zn(bib)(atibdc)]·2H_2O}{sub n} (1), {[Zn(bib)(atbip)]·H_2O}{sub n} (2), {[Zn(bib)(2,2′-tda)]}{sub n} (3) and {[Zn(bib)(5-tbipa)]·EtOH}{sub n} (4), (H{sub 2}atibdc=5-amino-2,4,6-triiodoisophthalic acid, H{sub 2}atbip=5-amino-2,4,6-tribromoisophthalic acid, 2,2′-H{sub 2}tad=2,2′-thiodiacetic acid, 5-H{sub 2}tbipa=5-tert-butyl-isophthalic acid). 1 reveals a 3D chiral framework with three kinds of helical chains along a, b and c axis. 2 shows a 2D step-type chiral framework with right-handed helical chains. 3 displays a wavelike 2D layer network possessing alternate left- and right-handed helical chains. 4 presents a four-connected 3D framework with zigzag and meso-helical chains. The different spacers and substituent group of carboxylic acid ligands may lead to the diverse network structures of 1–4. The fluorescent properties of complexes 1−4 were studied. In addition, the thermal decompositions properties of 1–4 were investigated by simultaneous TG/DTG–DSC technique. The apparent activation energy E and the pre-exponential factor (A) of skeleton collapse for the complexes 1–4 are calculated by the integral Kissinger's method and Ozawa–Doyle's method. The activation energy E (E{sub 1}=209.658 kJ·mol{sup −1}, E{sub 2}=250.037 kJ mol{sup −1}, E{sub 3}=225.300 kJ mol{sup −1}, E{sub 4}=186.529 kJ·mol{sup −1}) demonstrates that the reaction rate of the melting decomposition is slow. The thermodynamic parameters (ΔH{sup ‡}, ΔG{sup ‡} and ΔS{sup ‡}) at the peak temperatures of the DTG curves were also calculated. ΔG{sup ‡}>0 indicates that the skeleton collapse is not spontaneous. ΔH{sub d}>0 suggests that the skeleton collapse is endothermic, corresponding to the intense endothermic peak of the DSC

  2. Deuterium transport and trapping in polycrystalline tungsten

    International Nuclear Information System (INIS)

    Anderl, R.A.; Holland, D.F.; Longhurst, G.R.; Pawelko, R.J.; Trybus, C.L.; Sellers, C.H.

    1992-01-01

    This paper reports that deuterium permeation studies for polycrystalline tungsten foil have been conducted to provide data for estimating tritium transport and trapping in tungsten-clad divertors proposed for advanced fusion-reactor concepts. Based on a detailed transmission electron microscopy (TEM) microstructural characterization of the specimen material and on analyses of permeation data measured at temperatures ranging form 610 to 823 K for unannealed and annealed tungsten foil (25 μm thick), the authors note the following key results: deuterium transport in tungsten foil is dominated by extensive trapping that varies inversely with prior anneal temperatures of the foil material, the reduction in the trapped fraction correlates with a corresponding elimination of a high density of dislocations in cell-wall structures introduced during the foil fabrication process, trapping behavior in these foils can be modelled using trap energies between 1.3 eV and 1.5 eV and trap densities ranging from 1 x 10 -5 atom fraction

  3. The Use of Camera Traps in Wildlife

    Directory of Open Access Journals (Sweden)

    Yasin Uçarlı

    2013-11-01

    Full Text Available Camera traps are increasingly used in the abundance and density estimates of wildlife species. Camera traps are very good alternative for direct observation in case, particularly, steep terrain, dense vegetation covered areas or nocturnal species. The main reason for the use of camera traps is eliminated that the economic, personnel and time loss in a continuous manner at the same time in different points. Camera traps, motion and heat sensitive, can take a photo or video according to the models. Crossover points and feeding or mating areas of the focal species are addressed as a priority camera trap set locations. The population size can be finding out by the images combined with Capture-Recapture methods. The population density came out the population size divided to effective sampling area size. Mating and breeding season, habitat choice, group structures and survival rates of the focal species can be achieved from the images. Camera traps are very useful to obtain the necessary data about the particularly mysterious species with economically in planning and conservation efforts.

  4. Physics with Trapped Antihydrogen

    Science.gov (United States)

    Charlton, Michael

    2017-04-01

    For more than a decade antihydrogen atoms have been formed by mixing antiprotons and positrons held in arrangements of charged particle (Penning) traps. More recently, magnetic minimum neutral atom traps have been superimposed upon the anti-atom production region, promoting the trapping of a small quantity of the antihydrogen yield. We will review these advances, and describe some of the first physics experiments performed on anrtihydrogen including the observation of the two-photon 1S-2S transition, invesigation of the charge neutrailty of the anti-atom and studies of the ground state hyperfine splitting. We will discuss the physics motivations for undertaking these experiments and describe some near-future initiatives.

  5. Genetic structure and evolution of the Vps25 family, a yeast ESCRT-II component

    Directory of Open Access Journals (Sweden)

    Slater Ruth

    2006-08-01

    Full Text Available Abstract Background Vps25p is the product of yeast gene VPS25 and is found in an endosomal sorting complex required for transport (ESCRT-II, along with Vps22p and Vps36p. This complex is essential for sorting of ubiquitinated biosynthetic and endosomal cargoes into endosomes. Results We found that VPS25 is a highly conserved and widely expressed eukaryotic gene, with single orthologs in chromalveolate, excavate, amoebozoan, plant, fungal and metazoan species. Two paralogs were found in Trichomonas vaginalis. An ortholog was strikingly absent from the Encephalitozoon cuniculi genome. Intron positions were analyzed in VPS25 from 36 species. We found evidence for five ancestral VPS25 introns, intron loss, and single instances of intron gain (a Paramecium species and intron slippage (Theileria species. Processed pseudogenes were identified in four mammalian genomes, with a notable absence in the mouse genome. Two retropseudogenes were found in the chimpanzee genome, one more recently inserted, and one evolving from a common primate ancestor. The amino acid sequences of 119 Vps25 orthologs are aligned, compared with the known secondary structure of yeast Vps25p, and used to carry out phylogenetic analysis. Residues in two amino-terminal PPXY motifs (motif I and II, involved in dimerization of Vps25p and interaction with Vps22p and Vps36p, were closely, but not absolutely conserved. Specifically, motif I was absent in Vps25 homologs of chromalveolates, euglenozoa, and diplomonads. A highly conserved carboxy-terminal lysine was identified, which suggests Vps25 is ubiquitinated. Arginine-83 of yeast Vps25p involved in Vps22p interaction was highly, but not absolutely, conserved. Human tissue expression analysis showed universal expression. Conclusion We have identified 119 orthologs of yeast Vps25p. Expression of mammalian VPS25 in a wide range of tissues, and the presence in a broad range of eukaryotic species, indicates a basic role in eukaryotic cell

  6. Unprecedented Hexanuclear Cobalt(II Nonsymmetrical Salamo-Based Coordination Compound: Synthesis, Crystal Structure, and Photophysical Properties

    Directory of Open Access Journals (Sweden)

    Zong-Li Ren

    2018-03-01

    Full Text Available A novel hexanuclear Co(II coordination compound with a nonsymmetrical Salamo-type bisoxime ligandH4L, namely [{Co3(HL(MeO(MeOH2(OAc2}2]·2MeOH, was prepared and characterized by elemental analyses, UV–vis, IR and fluorescence spectra, and X-ray single-crystal diffraction analysis. Each Co(II is hexacoordinated, and possesses a distorted CoO6 or CoO4N2 octahedrons. The Co(II coordination compound possesses a self-assembled infinite 2D supramolecular structure with the help of the intermolecular C–H···O interactions. Meanwhile, the photophysical properties of the Co(II coordination compound were studied.

  7. Interfacial Charge-Carrier Trapping in CH3NH3PbI3-Based Heterolayered Structures Revealed by Time-Resolved Photoluminescence Spectroscopy.

    Science.gov (United States)

    Yamada, Yasuhiro; Yamada, Takumi; Shimazaki, Ai; Wakamiya, Atsushi; Kanemitsu, Yoshihiko

    2016-06-02

    The fast-decaying component of photoluminescence (PL) under very weak pulse photoexcitation is dominated by the rapid relaxation of the photoexcited carriers into a small number of carrier-trapping defect states. Here, we report the subnanosecond decay of the PL under excitation weaker than 1 nJ/cm(2) both in CH3NH3PbI3-based heterostructures and bare thin films. The trap-site density at the interface was evaluated on the basis of the fluence-dependent PL decay profiles. It was found that high-density defects determining the PL decay dynamics are formed near the interface between CH3NH3PbI3 and the hole-transporting Spiro-OMeTAD but not at the CH3NH3PbI3/TiO2 interface and the interior regions of CH3NH3PbI3 films. This finding can aid the fabrication of high-quality heterointerfaces, which are required improving the photoconversion efficiency of perovskite-based solar cells.

  8. Nuclear structure studies in the xenon and radon region and the discovery of a new radon isotope by Penning-trap mass spectrometry

    CERN Document Server

    Neidherr, Dennis

    2010-01-01

    Nowadays high-precision mass measurements based on Penning traps allow a deep insight into the fundamental properties of nucleonic matter. To this end, the cyclotron frequency of an ion confined in a strong, homogeneous magnetic field B is determined. At the ISOLTRAP mass spectrometer at ISOLDE / CERN the masses of short-lived radioactive nuclei with half-lives down to several ten ms can be measured with an uncertainty in the order of 10$^{-8}$and below. ISOLTRAP consists of an RFQ cooler and buncher to cool and accumulate the ions coming from ISOLDE and a double Penning-trap system to first clean the ion samples and finally perform the mass measurements. Within this thesis the masses of neutron rich xenon and radon isotopes, namely $^{138-146}$Xe and $^{223-229}$Rn were determined, eleven of them for the first time. $^{229}$Rn was even discovered in this experiment and its half-life could be determined to roughly 12$^{+1.2}_{-1.3}$ s. Since the mass reflects all interactions inside the nucleus it is a unique...

  9. Ion trap device

    Science.gov (United States)

    Ibrahim, Yehia M.; Smith, Richard D.

    2016-01-26

    An ion trap device is disclosed. The device includes a series of electrodes that define an ion flow path. A radio frequency (RF) field is applied to the series of electrodes such that each electrode is phase shifted approximately 180 degrees from an adjacent electrode. A DC voltage is superimposed with the RF field to create a DC gradient to drive ions in the direction of the gradient. A second RF field or DC voltage is applied to selectively trap and release the ions from the device. Further, the device may be gridless and utilized at high pressure.

  10. Asymmetric ion trap

    Science.gov (United States)

    Barlow, Stephan E.; Alexander, Michael L.; Follansbee, James C.

    1997-01-01

    An ion trap having two end cap electrodes disposed asymmetrically about a center of a ring electrode. The inner surface of the end cap electrodes are conformed to an asymmetric pair of equipotential lines of the harmonic formed by the application of voltages to the electrodes. The asymmetry of the end cap electrodes allows ejection of charged species through the closer of the two electrodes which in turn allows for simultaneously detecting anions and cations expelled from the ion trap through the use of two detectors charged with opposite polarity.

  11. Synthesis, spectroscopic and DNA binding ability of Co{sup II}, Ni{sup II}, Cu{sup II} and Zn{sup II} complexes of Schiff base ligand (E)-1-(((1H-benzo[d]imidazol-2-yl)methylimino)methyl)naphthalen-2-ol. X-ray crystal structure determination of cobalt (II) complex

    Energy Technology Data Exchange (ETDEWEB)

    Yarkandi, Naeema H. [Chemistry Department, Faculty of Applied Science, Umm Al–Qura University, Makkah (Saudi Arabia); El-Ghamry, Hoda A., E-mail: helghamrymo@yahoo.com [Chemistry Department, Faculty of Applied Science, Umm Al–Qura University, Makkah (Saudi Arabia); Chemistry Department, Faculty of Science, Tanta University, Tanta (Egypt); Gaber, Mohamed [Chemistry Department, Faculty of Science, Tanta University, Tanta (Egypt)

    2017-06-01

    A novel Schiff base ligand, (E)-1-(((1H-benzo[d]imidazol-2-yl)methylimino)methyl)naphthalen-2-ol (HL), has been designed and synthesized in addition to its metal chelates [Co(L){sub 2}]·l2H{sub 2}O, [Ni(L)Cl·(H{sub 2}O){sub 2}].5H{sub 2}O, [Cu(L)Cl] and [Zn(L)(CH{sub 3}COO)]. The structures of the isolated compounds have been confirmed and identified by means of different spectral and physicochemical techniques including CHN analysis, {sup 1}H &{sup 13}C NMR, mass spectral analysis, molar conductivity measurement, UV–Vis, infrared, magnetic moment in addition to TGA technique. The infrared spectral results ascertained that the ligand acts as monobasic tridentate binding to the metal centers via deprotonated hydroxyl oxygen, azomethine and imidazole nitrogen atoms. The UV–Vis, magnetic susceptibility and molar conductivity data implied octahedral geometry for Co(II) & Ni(II) complexes, tetrahedral for Zn(II) complex and square planar for Cu(II) complex. X-ray structural analysis of Co(II) complex 1 has been reported and discussed. Moreover, the type of interaction between the ligand & its complexes towards salmon sperm DNA (SS-DNA) has been examined by the measurement of absorption spectra and viscosity which confirmed that the ligand and its complexes interact with DNA via intercalation interaction as concluded from the values of binding constants (K{sub b}). - Highlights: • Synthesis of Co{sup II}, Ni{sup II}, Cu{sup II} and Zn{sup II} complexes of the Schiff base ligand based on 2-(aminomethyl)benzimidazole moiety. • The constitutions and structures of the ligand and complexes were elucidated. • Molecular structure of Co{sup II} complex was confirmed by single crystal X-ray diffraction method. • The ligand and its complexes interact with SS-DNA via intercalation mods.

  12. Structural Iron (II) of Basaltic Glass as an Energy Source for Zetaproteobacteria in an Abyssal Plain Environment, Off the Mid Atlantic Ridge.

    Science.gov (United States)

    Henri, Pauline A; Rommevaux-Jestin, Céline; Lesongeur, Françoise; Mumford, Adam; Emerson, David; Godfroy, Anne; Ménez, Bénédicte

    2015-01-01

    To explore the capability of basaltic glass to support the growth of chemosynthetic microorganisms, complementary in situ and in vitro colonization experiments were performed. Microbial colonizers containing synthetic tholeitic basaltic glasses, either enriched in reduced or oxidized iron, were deployed off-axis from the Mid Atlantic Ridge on surface sediments of the abyssal plain (35°N; 29°W). In situ microbial colonization was assessed by sequencing of the 16S rRNA gene and basaltic glass alteration was characterized using Scanning Electron Microscopy, micro-X-ray Absorption Near Edge Structure at the Fe-K-edge and Raman microspectroscopy. The colonized surface of the reduced basaltic glass was covered by a rind of alteration made of iron-oxides trapped in a palagonite-like structure with thicknesses up to 150 μm. The relative abundance of the associated microbial community was dominated (39% of all reads) by a single operational taxonomic unit (OTU) that shared 92% identity with the iron-oxidizer Mariprofundus ferrooxydans PV-1. Conversely, the oxidized basaltic glass showed the absence of iron-oxides enriched surface deposits and correspondingly there was a lack of known iron-oxidizing bacteria in the inventoried diversity. In vitro, a similar reduced basaltic glass was incubated in artificial seawater with a pure culture of the iron-oxidizing M. ferrooxydans DIS-1 for 2 weeks, without any additional nutrients or minerals. Confocal Laser Scanning Microscopy revealed that the glass surface was covered by twisted stalks characteristic of this iron-oxidizing Zetaproteobacteria. This result supported findings of the in situ experiments indicating that the Fe(II) present in the basalt was the energy source for the growth of representatives of Zetaproteobacteria in both the abyssal plain and the in vitro experiment. In accordance, the surface alteration rind observed on the reduced basaltic glass incubated in situ could at least partly result from their activity.

  13. Structural diversity and fluorescence properties of three 2-sulfoterephthalate Cd{sup II}/Zn{sup II} coordination polymers employing 1,4-bisbenzimidazole

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Yixia, E-mail: renyixia1@163.com; Chai, Hongmei; Tang, Long; Hou, Xiangyang; Wang, Jijiang

    2016-02-15

    Three novel coordination polymers, namely, [Cd(2-Hstp)(1,4-bbi)(H{sub 2}O){sub 2}]·3H{sub 2}O (1), [Cd{sub 1.5}(2-stp)(1,4-bbi)(H{sub 2}O){sub 2}]·H{sub 2}O (2) and [Zn{sub 2}(2-stp)(μ{sub 2}-OH)(1,4-bbi){sub 1.5}(H{sub 2}O)]·6H{sub 2}O (3) (2-H{sub 3}stp is equal to 2-sulfoterephthalate and 1,4-bisbenzimidazole is equal to 1,4-bbi), have been synthesized by hydrothermal reaction. The structural analyses show that 1 and 2 possess different structural features despite the same raw materials, which are 1D chain structure featuring 6-member-water H-bonds cluster and 3D bbi-pillared wavy-like layer framework, respectively. As changing the metal ion to zinc ion, 3 exhibits 3D stp-pillared layer architecture, which discovers the effect of the central metal ions on the formation of metal–organic frameworks. The fluorescence studies show that the emissions of the coordination polymers are attributed to the ligand π–π* transition, which means they could be potential fluorescence materials. - Graphical abstract: Three new Cd{sup II}/Zn{sup II} 2-sulfoterephthalate (2-H{sub 3}stp) complexes with 1,4-bisbenzimidazole (1,4-bbi) are described. Complex 1 exhibits one-dimensional chain-like structure, 2 is a three-dimensional bbi-pillared wavy-like layer framework, while 3 is a three-dimensional stp-pillared layer architecture. Fluorescence spectra exhibit the π–π* transition of two organic ligands. - Highlights: • Three Cd{sup II}/Mn{sup II} 2-sulfoterephthalate complexes containing 1,4-bisbenzimidazole. • Different structural features despite the same raw materials for 1 and 2. • Fluorescence spectra exhibit the π–π* transition of organic ligands.

  14. The n-propyl 3-azido-2,3-dideoxy-β-D-arabino-hexopyranoside: Syntheses, crystal structure, physical properties and stability constants of their complexes with Cu(II), Ni(II) and VO(II)

    Science.gov (United States)

    Barabaś, Anna; Madura, Izabela D.; Marek, Paulina H.; Dąbrowska, Aleksandra M.

    2017-11-01

    The structure, conformation and configuration of the n-propyl 3-azido-2,3-dideoxy-β-D-arabino-hexopyranoside (BAra-nPr) were determined by 1H NMR, 13C NMR, and IR spectroscopy, as well as by optical rotation. The crystal structure was confirmed by single-crystal X-ray diffraction studies at room temperature. The compound crystallizes in P21 space group symmetry of the monoclinic system. The molecule has a 4C1 chair conformation with azide group in the equatorial position both in a solution as well as in the crystal. The spatial arrangement of azide group is compared to other previously determined azidosugars. The hydrogen bonds between the hydroxyl group of sugar molecules lead to a ribbon structure observed also for the ethyl homolog. The packing of ribbons is dependent on the alkyl substituent length and with the elongation changes from pseudohexagonal to lamellar. Acidity constants for the n-propyl 3-azido-2,3-dideoxy-β-D-arabino-hexopyranoside (BAra-nPr) in an aqueous solution were evaluated by the spectrophotometric and potentiometric titrations methods. Title compound exhibit blue absorption with the maximum wavelengths in the range of 266 nm and 306 nm. Based on these measurements we showed equilibria existing in a particular solution and a distribution of species which have formed during the titration. We also investigated interactions between Cu(II), Ni(II) and VO(II) and title compound (as ligand L) during complexometric titration. On these bases we identified that in [CuII-BAra-nPr]2+ the ratio of the ligand L to metal ion M(II) was 3:1, while in [NiII-BAra-nPr]2+ and [VOII-BAra-nPr]2+ complexes 2:1 ratios were found. The cumulative stability constants (as log β) occurring in an aqueous solution for the complexes of BAra-nPr with Cu(II), Ni(II) and VO(IV) were 14.57; 11.71 and 4.20, respectively.

  15. Trapped Mode Study in the LHC Rotatable Collimator

    CERN Document Server

    Xiao, L; Smith, J C; Caspers, F

    2010-01-01

    A rotatable collimator is proposed for the LHC phase II collimation upgrade. When the beam crosses the collimator, trapped modes will be excited that result in beam energy loss and collimator power dissipation. Some of the trapped modes can also generate transverse kick on the beam and affect the beam operation. In this paper the parallel eigensolver code Omega3P is used to search for all the trapped modes below 2GHz in the collimator, including longitudinal modes and transverse modes. The loss factors and kick factors of the trapped modes are calculated as function of the jaw positions. The amplitude ratio between transverse and longitudinal trapped mode intensity can be used as a direct measure of the position of the beam. We present simulation results and discuss the results.

  16. A new Pb{sup II}(ethylenediaminetetraacetate) coordination polymer with a two-dimensional layer structure

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, D., E-mail: iamzd@hpu.edu.cn; Zhang, R. H.; Li, F. F. [Henan Polytechnic University, Department of Physics and Chemistry (China)

    2016-12-15

    A new Pb{sup II}−edta{sup 4–} coordination polymer, Pb{sub 2}(edta)(H{sub 2}O){sub 0.76} (edta{sup 4–} = ethylenediaminetetraacetate) was synthesized under hydrothermal condition. Single crystal X-ray analysis reveals that it represents a novel two-dimensional (2D) Pb{sup 2+}–edta{sup 4–} layer structure with a (4,8{sup 2})-topology. Each edta{sup 4–} ligand employs its four carboxylate O and two N atoms to chelate one Pb{sup II} atom (hexa-coordinated) and connects five Pb{sup II} atoms (ennea-coordinated) via its four carboxylate groups to form 2D layer framework. Adjacent layers are packed into the overall structure through vander Waals interactions.

  17. Interface and oxide traps in high-κ hafnium oxide films

    International Nuclear Information System (INIS)

    Wong, H.; Zhan, N.; Ng, K.L.; Poon, M.C.; Kok, C.W.

    2004-01-01

    The origins of the interface trap generation and the effects of thermal annealing on the interface and bulk trap distributions are studied in detail. We found that oxidation of the HfO 2 /Si interface, removal of deep trap centers, and crystallization of the as-deposited film will take place during the post-deposition annealing (PDA). These processes will result in the removal of interface traps and deep oxide traps and introduce a large amount of shallow oxide traps at the grain boundaries of the polycrystalline film. Thus, trade-off has to be made in considering the interface trap density and oxide trap density when conducting PDA. In addition, the high interface trap and oxide trap densities of the HfO 2 films suggest that we may have to use the SiO 2 /HfO 2 stack or hafnium silicate structure for better device performance

  18. Quantum technologies for solid state physics using cold trapped ions

    International Nuclear Information System (INIS)

    Ferdinand Schmidt-Kaler

    2014-01-01

    The quantum states of ions are perfectly controlled, and may be used for fundamental research in quantum physics, as highlighted by the Nobel Prize given to Dave Wineland in 2012. Two directions of quantum technologies, followed by the Mainz group, have high impact on solid state physics: I) The delivery of single cold ions on demand for the deterministic doping of solid state materials with nm spatial precision to generate design-structures optimized for quantum processors. II) The simulation of solid state relevant Hamiltonians with AMO systems of one or two dimensional arrays of trapped ions. I will talk about the recent progress in both fields. http://www.quantenbit.de/#Number Sign#/publications/(author)

  19. Ultrahigh-performance liquid chromatography-ion trap mass spectrometry characterization of the steroidal saponins of Dioscorea panthaica Prain et Burkill and its application for accelerating the isolation and structural elucidation of steroidal saponins.

    Science.gov (United States)

    Wang, Weihao; Zhao, Ye; Jing, Wenguang; Zhang, Jun; Xiao, Hui; Zha, Qin; Liu, An

    2015-03-01

    Dioscorea panthaica is a traditional Chinese medicinal herb used in the treatment of various physiological conditions, including cardiovascular disease, gastropathy and hypertension. Steroidal saponins (SS) are the main active ingredients of this herb and have effects on myocardial ischemia and cancer. The phytochemical evaluation of SS is both time-consuming and laborious, and the isolation and structural determination steps can be especially demanding. For this reason, the development of new methods to accelerate the processes involved in the identification, isolation and structural elucidation of SS is highly desirable. In this study, a new ultrahigh performance liquid chromatography-ion trap mass spectrometry (UHPLC-IT/MS(n)) method has been developed for the identification of the SS in D. panthaica Prain et Burkill. Notably, the current method can distinguish between spirostanol and furostanol-type compounds based on the fragmentation patterns observed by electrospray ionization-ion trap mass spectrometry (ESI-IT/MS(n)) analysis. UHPLC-IT/MS(n) was used to conduct a detailed investigation of the number, structural class and order of the sugar moieties in the sugar chains of the SS present in D. panthaica. The established fragmentation features were used to analyze the compounds found in the 65% ethanol fraction of the water extracts of D. panthaica. Twenty-three SS were identified, including 11 potential new compounds and six groups of isomers. Two of these newly identified SS were selected as representative examples, and their chemical structures were confirmed by (1)H and (13)C NMR analyses. This newly developed UHPLC-IT/MS(n) method therefore allowed for the efficient identification, isolation and structural determination of the SS in D. panthaica. Copyright © 2015 Elsevier Inc. All rights reserved.

  20. Structural analysis of site-directed mutants of cellular retinoic acid-binding protein II addresses the relationship between structural integrity and ligand binding

    International Nuclear Information System (INIS)

    Vaezeslami, Soheila; Jia, Xiaofei; Vasileiou, Chrysoula; Borhan, Babak; Geiger, James H.

    2008-01-01

    A water network stabilizes the structure of cellular retionic acid binding protein II. The structural integrity of cellular retinoic acid-binding protein II (CRABPII) has been investigated using the crystal structures of CRABPII mutants. The overall fold was well maintained by these CRABPII mutants, each of which carried multiple different mutations. A water-mediated network is found to be present across the large binding cavity, extending from Arg111 deep inside the cavity to the α2 helix at its entrance. This chain of interactions acts as a ‘pillar’ that maintains the integrity of the protein. The disruption of the water network upon loss of Arg111 leads to decreased structural integrity of the protein. A water-mediated network can be re-established by introducing the hydrophilic Glu121 inside the cavity, which results in a rigid protein with the α2 helix adopting an altered conformation compared with wild-type CRABPII

  1. Influence of crystal structure on the CoII diffusion behavior in the Zn1-xCoxO system

    International Nuclear Information System (INIS)

    Peiteado, M.; Makovec, D.; Villegas, M.; Caballero, A.C.

    2008-01-01

    The solid state interaction of the Zn 1-x Co x O nominal system is investigated by means of diffusion couples and analysis of co-precipitated samples. The formation of a homogeneous Co:ZnO solid solution is found to be determined by the crystal structure from which Co II ions diffuse into the wurtzite lattice. No diffusion is observed whenever the CoO rock-salt structure is formed from the Co II precursor. On the contrary, the diffusion from the Co 3 O 4 spinel phase is feasible but has a limited temperature range defined by the reduction at a high temperature of Co III -Co II , since this process again leads to the formation of the rock-salt structure. However, when using a highly reactive and homogeneous co-precipitated starting powder, neither the spinel phase nor the rock-salt structure is formed, and a Co II :ZnO solid solution is obtained, which remains stable up to high temperatures. - Graphical abstract: Maximum diffusion distance for the ZnO-CoO x couple as a function of temperature. Dashed gray lines represent the temperature values at which the transformations between CoO and Co 3 O 4 compounds take place

  2. WATER-TRAPPED WORLDS

    International Nuclear Information System (INIS)

    Menou, Kristen

    2013-01-01

    Although tidally locked habitable planets orbiting nearby M-dwarf stars are among the best astronomical targets to search for extrasolar life, they may also be deficient in volatiles and water. Climate models for this class of planets show atmospheric transport of water from the dayside to the nightside, where it is precipitated as snow and trapped as ice. Since ice only slowly flows back to the dayside upon accumulation, the resulting hydrological cycle can trap a large amount of water in the form of nightside ice. Using ice sheet dynamical and thermodynamical constraints, I illustrate how planets with less than about a quarter the Earth's oceans could trap most of their surface water on the nightside. This would leave their dayside, where habitable conditions are met, potentially dry. The amount and distribution of residual liquid water on the dayside depend on a variety of geophysical factors, including the efficiency of rock weathering at regulating atmospheric CO 2 as dayside ocean basins dry up. Water-trapped worlds with dry daysides may offer similar advantages as land planets for habitability, by contrast with worlds where more abundant water freely flows around the globe

  3. Redesigning octopus traps

    Directory of Open Access Journals (Sweden)

    Eduarda Gomes

    2014-06-01

    In order to minimise the identified problems in the actual traps, the present work proposes a new design with the aim of reducing the volume and weight during transport, and also during onshore storage. Alternative materials to avoid corrosion and formation of encrustations were also proposed.

  4. WATER-TRAPPED WORLDS

    Energy Technology Data Exchange (ETDEWEB)

    Menou, Kristen [Department of Astronomy, Columbia University, 550 West 120th Street, New York, NY 10027 (United States)

    2013-09-01

    Although tidally locked habitable planets orbiting nearby M-dwarf stars are among the best astronomical targets to search for extrasolar life, they may also be deficient in volatiles and water. Climate models for this class of planets show atmospheric transport of water from the dayside to the nightside, where it is precipitated as snow and trapped as ice. Since ice only slowly flows back to the dayside upon accumulation, the resulting hydrological cycle can trap a large amount of water in the form of nightside ice. Using ice sheet dynamical and thermodynamical constraints, I illustrate how planets with less than about a quarter the Earth's oceans could trap most of their surface water on the nightside. This would leave their dayside, where habitable conditions are met, potentially dry. The amount and distribution of residual liquid water on the dayside depend on a variety of geophysical factors, including the efficiency of rock weathering at regulating atmospheric CO{sub 2} as dayside ocean basins dry up. Water-trapped worlds with dry daysides may offer similar advantages as land planets for habitability, by contrast with worlds where more abundant water freely flows around the globe.

  5. Two new layer structures of zinc(II) or strontium(II) diphosphonates based on N,N-dimethylaminomethane-1,1-diphosphonate ligand

    Science.gov (United States)

    Sun, Yu-Hui; Du, Zi-Yi; Zhou, Zhong-Gao; Zhang, Shi-Yong; Xu, Guo-Hai; Xie, Yong-Rong

    2011-05-01

    Hydrothermal reactions of Zn 2+ or Sr 2+ ion with N,N-dimethylaminomethane-1,1-diphosphonic acid (H 4L) afforded two new layered metal diphosphonates, namely, [Zn 2(H 2L) 2]·2H 2O ( 1) and [Sr 3(H 2L) 2(H 3L) 2(H 2O) 2]·2H 2O ( 2). The layer structure in 1 features a square-grid unit with Zn1O 6 octahedra acting as nodes, which tetradentately traps one Zn2 ion inside it. On the other hand, the layer architecture of 2 exhibits an unusual corner-sharing Sr 3O 17 tri-polyhedra unit; and such trimer unit is edge-shared with two neighboring trimers, which further chelate a third trimer to form a square-grid ring with two aqua molecules residing in it. The diphosphonate ligand in the two compounds manifests diversified coordination modes accompanying with a cooperative coordination effect of its two closely linked phosphonate moieties.

  6. Synthesis and Characterization of Cu(II), Co(II) and Ni(II) Complexes of Trithiocyanuric Acid: The Structure of {N,N'-Bis(3-Aminopropyl)-1,3-Propanediamine}-(Trithiocyanurato)Nickel(II)

    Czech Academy of Sciences Publication Activity Database

    Kopel, P.; Trávníček, Zdeněk; Kvítek, L.; Černošek, Z.; Wrzeszcz, G.; Marek, J.

    2003-01-01

    Roč. 56, č. 1 (2003), s. 1-11 ISSN 0095-8972 R&D Projects: GA ČR GA203/00/0152; GA AV ČR IBS5038351 Institutional research plan: CEZ:AV0Z5038910 Keywords : Copper(II) * cobalt(II) and nickel(II) complexes * Trithiocyanuric acid Subject RIV: CE - Biochemistry Impact factor: 0.841, year: 2003

  7. Life spans of planktonic foraminifers: New sight through sediment traps

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.; Saraswat, R.; Mazumder, A.

    ), indicated by black arrows are remarkably present for all three trap locations. (Modified after Curry et l.t 1992). 2002; Eguchi, Ujiie, Kawahata and Taira 2003), (ii) all the traps can not stop functioning simultaneously and that for the same time... estimates of the life spans of planktonic foraminifera based on extrapolation of lab culture observations. According to Be et al (1981), an inverse relationship exists between feeding frequency and survival time, and that planktonic foraminifers under...

  8. Synthesis, structural, photoluminescence, vibrational and DFT investigation of the bis (4-aminopyridinium) tetrachloridocuprate(II) monohydrate

    International Nuclear Information System (INIS)

    Kessentini, A.; Belhouchet, M.; Suñol, J.J.; Abid, Y.; Mhiri, T.

    2014-01-01

    The crystals of the family of alkylammonuim tetrachloridocuprate (II), (C 5 H 7 N 2 ) 2 CuCl 4 H 2 O, have been grown, structurally characterized and their vibrational as well as optical properties been studied. A preliminary single crystal X-ray diffraction structural analysis has revealed that the title compound belongs to the monoclinic system with space group C2/c. Its unit cell dimensions are: a=8.454 (2) Å, b=14.279 (2) Å, c=14.363 (3) Å, β=95.813 (4)°, with Z=4 and its crystal structure was determined and refined down to R 1 =0.029 and wR 2 =0.080. The crystal lattice is composed of discrete [CuCl 4 ] 2− tetrahedra surrounded by 4-aminopyridinium cations and water molecules which are interconnected by means of hydrogen bonding contacts [N–H…Cl, O–H…Cl and N–H…O]. Furthermore, the room temperature IR and Raman spectra of the title compound were recorded and analyzed. The optimized molecular structure and the vibrational spectra were calculated by the density functional theory (DFT) method using the B3LYP function. The organic–inorganic hybrid crystal thin film can be easily prepared by spin-coating method from the ethanol solution of the (C 5 H 7 N 2 ) 2 CuCl 4 H 2 O perovskite and it showed characteristic absorptions of CuCl-based layered perovskite centered at 288 and 400 nm, as well as the photoluminescence peak at around 443 nm. The unaided-eye-detectable blue luminescence emission comes from the excitonic transition in the CuCl 4 anions. - Highlights: • A new hybrid compound (C 5 H 7 N 2 ) 2 CuCl 4 H 2 O was synthesized. • Vibrational properties were studied by IR and Raman spectroscopy and examined theoretically using the DFT/B3LYP/LanL2DZ level of theory. • The UV–vis spectrum shows two absorption peaks at 288 and at 400 nm. • This compound show a strong blue emission at 443 nm

  9. Structural oxidation state studies of the manganese cluster in the oxygen evolving complex of photosystem II

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Wenchuan [Univ. of California, Berkeley, CA (United States)

    1994-11-01

    X-ray absorption spectroscopy (XAS) was performed on Photosystem II (PSII)-enriched membranes prepared from spinach to explore: (1) the correlation between structure and magnetic spin state of the Mn cluster in the oxygen evolving complex (OEC) in the S2 state; and (2) the oxidation state changes of the Mn cluster in the flash-induced S-states. The structure of the Mn cluster in the S2 state with the g~4 electron paramagnetic resonance (EPR) signal (S2-g4 state) was compared with that in the S2 state with multiline signal (S2-MLS state) and the S1 state. The S2-g4 state has a higher XAS inflection point energy than that of the S1 state, indicating the oxidation of Mn in the advance from the S1 to the S2-g4 state. Differences in the edge shape and in the extended X-ray absorption fine structure (EXAFS) show that the structure of the Mn cluster in the S2-g4 state is different from that in the S2-MLS or the S1 state. In the S2-g4 state, the second shell of backscatterers from the Mn absorber contains two Mn-Mn distances of 2.73 Å and 2.85 Å. Very little distance disorder exists in the second shell of the S1 or S2-MLS states. The third shell of the S2-g4 state at about 3.3 Å also contains increased heterogeneity relative to that of the S2-MLS or the S1 state. Various S-states were prepared at room-temperature by saturating, single-turnover flashes. The flash-dependent oscillation in the amplitude of the MLS was used to characterize the S-state composition and to construct "pure" S-state Mn K-edge spectra. The edge position shifts to higher energy by 1.8 eV upon the S1 → S2 transition.

  10. Synthesis, structural, photoluminescence, vibrational and DFT investigation of the bis (4-aminopyridinium) tetrachloridocuprate(II) monohydrate

    Energy Technology Data Exchange (ETDEWEB)

    Kessentini, A., E-mail: kessentiniabir@gmail.com [Laboratoire Physico-Chimie de l’Etat Solide, Département de Chimie, Faculté des Sciences de Sfax, Université de Sfax, B. P. 1171, 3000 Sfax (Tunisia); Belhouchet, M. [Laboratoire Physico-Chimie de l’Etat Solide, Département de Chimie, Faculté des Sciences de Sfax, Université de Sfax, B. P. 1171, 3000 Sfax (Tunisia); Suñol, J.J. [Departamento De Fisica, Universita de Girona, Compus Montilivi, Girona 17071 (Spain); Abid, Y. [Laboratoire de Physique appliquée, Faculté des Sciences de Sfax, Université de Sfax, B. P. 1171, 3000 Sfax (Tunisia); Mhiri, T. [Laboratoire Physico-Chimie de l’Etat Solide, Département de Chimie, Faculté des Sciences de Sfax, Université de Sfax, B. P. 1171, 3000 Sfax (Tunisia)

    2014-05-01

    The crystals of the family of alkylammonuim tetrachloridocuprate (II), (C{sub 5}H{sub 7}N{sub 2}){sub 2}CuCl{sub 4}H{sub 2}O, have been grown, structurally characterized and their vibrational as well as optical properties been studied. A preliminary single crystal X-ray diffraction structural analysis has revealed that the title compound belongs to the monoclinic system with space group C2/c. Its unit cell dimensions are: a=8.454 (2) Å, b=14.279 (2) Å, c=14.363 (3) Å, β=95.813 (4)°, with Z=4 and its crystal structure was determined and refined down to R{sub 1}=0.029 and wR{sub 2}=0.080. The crystal lattice is composed of discrete [CuCl{sub 4}]{sup 2−} tetrahedra surrounded by 4-aminopyridinium cations and water molecules which are interconnected by means of hydrogen bonding contacts [N–H…Cl, O–H…Cl and N–H…O]. Furthermore, the room temperature IR and Raman spectra of the title compound were recorded and analyzed. The optimized molecular structure and the vibrational spectra were calculated by the density functional theory (DFT) method using the B3LYP function. The organic–inorganic hybrid crystal thin film can be easily prepared by spin-coating method from the ethanol solution of the (C{sub 5}H{sub 7}N{sub 2}){sub 2}CuCl{sub 4}H{sub 2}O perovskite and it showed characteristic absorptions of CuCl-based layered perovskite centered at 288 and 400 nm, as well as the photoluminescence peak at around 443 nm. The unaided-eye-detectable blue luminescence emission comes from the excitonic transition in the CuCl{sub 4} anions. - Highlights: • A new hybrid compound (C{sub 5}H{sub 7}N{sub 2}){sub 2}CuCl{sub 4}H{sub 2}O was synthesized. • Vibrational properties were studied by IR and Raman spectroscopy and examined theoretically using the DFT/B3LYP/LanL2DZ level of theory. • The UV–vis spectrum shows two absorption peaks at 288 and at 400 nm. • This compound show a strong blue emission at 443 nm.

  11. Organic derivatives of tin (II/IV): Investigation of their structure

    Energy Technology Data Exchange (ETDEWEB)

    Szirtes, L., E-mail: szirtes@iki.kfki.h [Institute of Isotopes of the Hungarian Academy of Sciences, Budapest H-1525, P.O. Box 77 (Hungary); Megyeri, J., E-mail: megyeri@iki.kfki.h [Institute of Isotopes of the Hungarian Academy of Sciences, Budapest H-1525, P.O. Box 77 (Hungary); Kuzmann, E. [Laboratory of Nuclear Chemistry, CRC of the Hungarian Academy of Science at Eoetvoes University, H-1518 Budapest, P.O. Box 32 (Hungary); Beck, A. [Institute of Isotopes of the Hungarian Academy of Sciences, Budapest H-1525, P.O. Box 77 (Hungary)

    2011-07-15

    The structures of tin(II)-oxalate, tin(IV)Na-EDTA and tin(IV)Na{sub 8}-inositol hexaphosphate were investigated using XRD analysis. Samples were identified using the Moessbauer study, thermal analysis and FTIR spectrometry. The Moessbauer study determined two different oxidation states of tin atoms, and consequently two different tin surroundings in the end products. The tin oxalate was found to be orthorhombic with space group Pnma, a=9.2066(3) A, b=9.7590(1) A, c=13.1848(5) A, V=1184.62 A{sup 3} and Z=8. SnNa-EDTA was found to be monoclinic with space group P2{sub 1}/c{sub 1}, a=10.7544(3) A, b=10.1455(3) A, c=16.5130(6) A, {beta}=98.59(2){sup o}, V=1781.50(4) A{sup 3} and Z=4. Sn(C{sub 6}H{sub 6}Na{sub 8}O{sub 24}P{sub 6}) was found to be amorphous.

  12. Damage analysis of TRIGA MARK II Bandung reactor tank material structure

    International Nuclear Information System (INIS)

    Soedardjo; Sumijanto

    2000-01-01

    Damage of Triga Mark II Bandung reactor tank material structure has been analyzed. The analysis carried out was based on ultrasonic inspection result in 1996 and the monthly reports of reactor operation by random data during 1988 up to 1995. Ultrasonic test data had shown that thinning processes on south and west region of reactor out side wall at upper part of water level had happened. Reactor operation data had shown the demineralized water should be added monthly to the reactor and bulk shielding water tank. Both reactor and bulk shielding tank are shielded by concrete of Portland type I cement consisting of CaO content about 58-68 %. The analysis result shows that the reaction between CaO and seepage water from bulk shielding wall had taken place and consequently the reactor out sidewall surroundings became alkaline. Based on Pourbaix diagram, the aluminum reactor tank made of aluminum alloy 6061 T6 would be corroded easily at pH equal an greater than 8.6. The passive layer AI 2 O 3 aluminum metal surface would be broken due to water reaction taken place continuously at high pH and produces hydrogen gas. The light hydrogen gas would expand the concrete cement and its expanding power would open the passive layer of aluminum metal upper tank. The water sea pages from adding water into reactor tank could indicate the upper water level tank corrosion is worse than the lower water level tank. (author)

  13. Synthesis and Crystal Structure of Dinuclear Cadmium(II) Complex with Dipodal Ligand

    International Nuclear Information System (INIS)

    Kang, Young Jin; Moon, Suk Hee; Byun, Jong Chul; Park, Ki Min

    2010-01-01

    the preparation and structural characterization of the discrete dinuclear cadmium(II) complex with the formula [Cd(μ 2 -Cl) 2 Cl 2 ]· 2 (H 2 O)·0.5(CH 3 OH)·0.5(CH 3 CN) obtained from the reaction of CdCl 2 ·2.5H 2 O and podal ligand with quinoline end-groups has been reported. In two cadmium ions are triply bridged by two chloride and one donor atoms of ligand L and adopt distorted pentagonal bipyramidal geometries with seven coordinations. It is notable that example of discrete dinuclear complex which one podal ligand accommodates simultaneously two metal ions is very rare. During the last four decades, the chemistry of macrocyclic and non-cyclic polyethers has attracted an increasing attention because of their selective complexation, cation transport and enzyme chemistry. In the field of coordination chemistry, generally, non-cyclic, crown-type polyether affords the low complexation ability because of its conformational freedom while macrocyclic polyethers such as 18-crown-6 show the excellent complexing ability

  14. Tuning the structural and optical properties of gold/silver nanoalloys prepared by laser ablation in liquids for ultra-sensitive spectroscopy and optical trapping

    Directory of Open Access Journals (Sweden)

    F. Neri

    2011-09-01

    Full Text Available The plasmon resonance of metallic Au/Ag alloys in the colloidal state was tuned from 400 nm to 500 nm using a laser irradiated technique, performed directly in the liquid state. Interesting optical nonlinearities, trapping effects and spectroscopic enhancements were detected as function of gold concentration in the nanoalloys. In particular a reduction of the limiting threshold was observed by increasing the gold amount. The SERS activity of the Au/Ag alloys was tested in liquid and in solid state in presence of linear carbon chains as probe molecules. The dependence of the increased Raman signals on the nanoparticle Au/Ag atomic ratio is presented and discussed. Finally preliminary studies and prospects for optical and Raman tweezers experiments are discussed.

  15. Nuclear structure studies in the xenon and radon region and the discovery of a new radon isotope by Penning trap mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Neidherr, Dennis

    2010-04-28

    Nowadays high-precision mass measurements based on Penning traps allow a deep insight into the fundamental properties of nucleonic matter. To this end, the cyclotron frequency {nu}{sub c}=qB=(2{pi}m) of an ion confined in a strong, homogeneous magnetic field B is determined. At the ISOLTRAP mass spectrometer at ISOLDE / CERN the masses of short-lived radioactive nuclei with half-lives down to several ten ms can be measured with an uncertainty in the order of 10{sup -8} and below. ISOLTRAP consists of an RFQ cooler and buncher to cool and accumulate the ions coming from ISOLDE and a double Penning trap system to first clean the ion samples and finally perform the mass measurements. Within this thesis the masses of neutron rich xenon and radon isotopes, namely {sup 138-146}Xe and {sup 223-229}Rn were determined, eleven of them for the first time. {sup 229}Rn was even discovered in this experiment and its half-life could be determined to 12{sub -1.3}{sup +1.2} s. Since the mass reflects all interactions inside the nucleus it is a unique fingerprint of the nuclide of interest. One of these interactions, the proton-neutron interaction, leads for example to the onset of deformation. The aim of this thesis is to investigate a possible connection be- tween collective effects in nuclei, like the onset of deformation, and double-differences of binding energies, so called {delta}V{sub pn} values. Especially in the here presented areas these {delta}V{sub pn} values show a very unusual behavior and can not be explained with simple orbital overlapping arguments. One explanation could be the occurrence of octupolar deformation in these regions, which is usually probed with other experimental techniques. However, a quantitative description of the influence of such type of deformation on {delta}V{sub pn} is still not possible with modern theories. (orig.)

  16. Nuclear structure studies in the xenon and radon region and the discovery of a new radon isotope by Penning trap mass spectrometry

    International Nuclear Information System (INIS)

    Neidherr, Dennis

    2010-01-01

    Nowadays high-precision mass measurements based on Penning traps allow a deep insight into the fundamental properties of nucleonic matter. To this end, the cyclotron frequency ν c =qB=(2πm) of an ion confined in a strong, homogeneous magnetic field B is determined. At the ISOLTRAP mass spectrometer at ISOLDE / CERN the masses of short-lived radioactive nuclei with half-lives down to several ten ms can be measured with an uncertainty in the order of 10 -8 and below. ISOLTRAP consists of an RFQ cooler and buncher to cool and accumulate the ions coming from ISOLDE and a double Penning trap system to first clean the ion samples and finally perform the mass measurements. Within this thesis the masses of neutron rich xenon and radon isotopes, namely 138-146 Xe and 223-229 Rn were determined, eleven of them for the first time. 229 Rn was even discovered in this experiment and its half-life could be determined to 12 -1.3 +1.2 s. Since the mass reflects all interactions inside the nucleus it is a unique fingerprint of the nuclide of interest. One of these interactions, the proton-neutron interaction, leads for example to the onset of deformation. The aim of this thesis is to investigate a possible connection be- tween collective effects in nuclei, like the onset of deformation, and double-differences of binding energies, so called δV pn values. Especially in the here presented areas these δV pn values show a very unusual behavior and can not be explained with simple orbital overlapping arguments. One explanation could be the occurrence of octupolar deformation in these regions, which is usually probed with other experimental techniques. However, a quantitative description of the influence of such type of deformation on δV pn is still not possible with modern theories. (orig.)

  17. Adverse Effects of Excess Residual PbI2 on Photovoltaic Performance, Charge Separation, and Trap-State Properties in Mesoporous Structured Perovskite Solar Cells.

    Science.gov (United States)

    Wang, Hao-Yi; Hao, Ming-Yang; Han, Jun; Yu, Man; Qin, Yujun; Zhang, Pu; Guo, Zhi-Xin; Ai, Xi-Cheng; Zhang, Jian-Ping

    2017-03-17

    Organic-inorganic halide perovskite solar cells have rapidly come to prominence in the photovoltaic field. In this context, CH 3 NH 3 PbI 3 , as the most widely adopted active layer, has been attracting great attention. Generally, in a CH 3 NH 3 PbI 3 layer, unreacted PbI 2 inevitably coexists with the perovskite crystals, especially following a two-step fabrication process. There appears to be a consensus that an appropriate amount of unreacted PbI 2 is beneficial to the overall photovoltaic performance of a device, the only disadvantageous aspect of excess residual PbI 2 being viewed as its insulating nature. However, the further development of such perovskite-based devices requires a deeper understanding of the role of residual PbI 2 . In this work, PbI 2 -enriched and PbI 2 -controlled perovskite films, as two extreme cases, have been prepared by modulating the crystallinity of a pre-deposited PbI 2 film. The effects of excess residual PbI 2 have been elucidated on the basis of spectroscopic and optoelectronic studies. The initial charge separation, the trap-state density, and the trap-state distribution have all been found to be adversely affected in PbI 2 -enriched devices, to the detriment of photovoltaic performance. This leads to a biphasic recombination process and accelerates the charge carrier recombination dynamics. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. A new photoactive Ru(II)tris(2,2'-bipyridine) templated Zn(II) benzene-1,4-dicarboxylate metal organic framework: structure and photophysical properties.

    Science.gov (United States)

    Whittington, Christi L; Wojtas, Lukasz; Gao, Wen-Yang; Ma, Shengqian; Larsen, Randy W

    2015-03-28

    It has now been demonstrated that Ru(ii)tris(2,2'-bipyridine) (RuBpy) can be utilized to template the formation of new metal organic framework (MOF) materials containing crystallographically resolved RuBpy clusters with unique photophysical properties. Two such materials, RWLC-1 and RWLC-2, have now been reported from our laboratory and are composed of RuBpy encapsulated in MOFs composed of Zn(ii) ions and 1,3,5-tris(4-carboxyphenyl)benzene ligands (C. L. Whittington, L. Wojtas and R. W. Larsen, Inorg. Chem., 2014, 53, 160-166). Here, a third RuBpy templated photoactive MOF is described (RWLC-3) that is derived from the reaction between Zn(ii) ions and 1,4-dicarboxybenzene in the presence of RuBpy. Single Crystal X-ray diffraction studies determined the position of RuBpy cations within the crystal lattice. The RWLC-3 structure is described as a 2-fold interpenetrated pillared honeycomb network (bnb) containing crystallographically resolved RuBpy clusters. The two bnb networks are weakly interconnected. The encapsulated RuBpy exhibits two emission decay lifetimes (τ-fast = 120 ns, τ-slow = 453 ns) and a bathochromic shift in the steady state emission spectrum relative to RuBpy in ethanol.

  19. Thermal and hydraulic analyses of the System 81 cold traps

    Energy Technology Data Exchange (ETDEWEB)

    Kim, K.

    1977-06-15

    Thermal and hydraulic analyses of the System 81 Type I and II cold traps were completed except for thermal transients analysis. Results are evaluated, discussed, and reported. Analytical models were developed to determine the physical dimensions of the cold traps and to predict the performance. The FFTF cold trap crystallizer performances were simulated using the thermal model. This simulation shows that the analytical model developed predicts reasonably conservative temperatures. Pressure drop and sodium residence time calculations indicate that the present design will meet the requirements specified in the E-Specification. Steady state temperature data for the critical regions were generated to assess the magnitude of the thermal stress.

  20. Theoretical modeling of the electronic structure and exchange interactions in a Cu(II)Pc one-dimensional chain

    Science.gov (United States)

    Wu, Wei; Fisher, A. J.; Harrison, N. M.

    2011-07-01

    We calculate the electronic structure and exchange interactions in a copper(II)phthalocyanine [Cu(II)Pc] crystal as a one-dimensional molecular chain using hybrid exchange density functional theory (DFT). In addition, the intermolecular exchange interactions are also calculated in a molecular dimer using Green’s function perturbation theory (GFPT) to illustrate the underlying physics. We find that the exchange interactions depend strongly on the stacking angle, but weakly on the sliding angle (defined in the text). The hybrid DFT calculations also provide an insight into the electronic structure of the Cu(II)Pc molecular chain and demonstrate that on-site electron correlations have a significant effect on the nature of the ground state, the band gap, and magnetic excitations. The exchange interactions predicted by our DFT calculations and GFPT calculations agree qualitatively with the recent experimental results on newly found η-Cu(II)Pc and the previous results for the α and β phases. This work provides a reliable theoretical basis for the further application of Cu(II)Pc to molecular spintronics and organic-based quantum information processing.

  1. Structural characterization of copper(II) binding to α-synuclein: Insights into the bioinorganic chemistry of Parkinson's disease

    Science.gov (United States)

    Rasia, Rodolfo M.; Bertoncini, Carlos W.; Marsh, Derek; Hoyer, Wolfgang; Cherny, Dmitry; Zweckstetter, Markus; Griesinger, Christian; Jovin, Thomas M.; Fernández, Claudio O.

    2005-01-01

    The aggregation of α-synuclein (AS) is characteristic of Parkinson's disease and other neurodegenerative synucleinopathies. We demonstrate here that Cu(II) ions are effective in accelerating AS aggregation at physiologically relevant concentrations without altering the resultant fibrillar structures. By using numerous spectroscopic techniques (absorption, CD, EPR, and NMR), we have located the primary binding for Cu(II) to a specific site in the N terminus, involving His-50 as the anchoring residue and other nitrogen/oxygen donor atoms in a square planar or distorted tetragonal geometry. The carboxylate-rich C terminus, originally thought to drive copper binding, is able to coordinate a second Cu(II) equivalent, albeit with a 300-fold reduced affinity. The NMR analysis of AS–Cu(II) complexes reveals the existence of conformational restrictions in the native state of the protein. The metallobiology of Cu(II) in Parkinson's disease is discussed by a comparative analysis with other Cu(II)-binding proteins involved in neurodegenerative disorders. PMID:15767574

  2. Synthesis, spectroscopic and DNA binding ability of CoII, NiII, CuII and ZnII complexes of Schiff base ligand (E)-1-(((1H-benzo[d]imidazol-2-yl)methylimino)methyl)naphthalen-2-ol. X-ray crystal structure determination of cobalt (II) complex.

    Science.gov (United States)

    Yarkandi, Naeema H; El-Ghamry, Hoda A; Gaber, Mohamed

    2017-06-01

    A novel Schiff base ligand, (E)-1-(((1H-benzo[d]imidazol-2-yl)methylimino)methyl)naphthalen-2-ol (HL), has been designed and synthesized in addition to its metal chelates [Co(L) 2 ]·l2H 2 O, [Ni(L)Cl·(H 2 O) 2 ].5H 2 O, [Cu(L)Cl] and [Zn(L)(CH 3 COO)]. The structures of the isolated compounds have been confirmed and identified by means of different spectral and physicochemical techniques including CHN analysis, 1 H & 13 C NMR, mass spectral analysis, molar conductivity measurement, UV-Vis, infrared, magnetic moment in addition to TGA technique. The infrared spectral results ascertained that the ligand acts as monobasic tridentate binding to the metal centers via deprotonated hydroxyl oxygen, azomethine and imidazole nitrogen atoms. The UV-Vis, magnetic susceptibility and molar conductivity data implied octahedral geometry for Co(II) & Ni(II) complexes, tetrahedral for Zn(II) complex and square planar for Cu(II) complex. X-ray structural analysis of Co(II) complex 1 has been reported and discussed. Moreover, the type of interaction between the ligand & its complexes towards salmon sperm DNA (SS-DNA) has been examined by the measurement of absorption spectra and viscosity which confirmed that the ligand and its complexes interact with DNA via intercalation interaction as concluded from the values of binding constants (K b ). Copyright © 2017 Elsevier B.V. All rights reserved.

  3. [Trapping techniques for Solenopsis invicta].

    Science.gov (United States)

    Liang, Xiao-song; Zhang, Qiang; Zhuang, Yiong-lin; Li, Gui-wen; Ji, Lin-peng; Wang, Jian-guo; Dai, Hua-guo

    2007-06-01

    A field study was made to investigate the trapping effects of different attractants, traps, and wind directions on Solenopsis invicta. The results showed that among the test attractants, TB1 (50 g fishmeal, 40 g peptone, 10 ml 10% sucrose water solution and 20 ml soybean oil) had the best effect, followed by TB2 (ham), TB6 (100 g cornmeal and 20 ml soybean oil) and TB4 (10 ml 10% sucrose water solution, 100 g sugarcane powder and 20 ml soybean oil), with a mean capture efficiency being 77.6, 58.7, 29 and 7.7 individuals per trap, respectively. No S. invicta was trapped with TB3 (10 ml 10% sucrose water solution, 100 g cornmeal and 20 ml soybean oil) and TB5 (honey). Tube trap was superior to dish trap, with a trapping efficiency of 75.2 and 35 individuals per trap, respectively. The attractants had better effects in leeward than in windward.

  4. Optical trapping of gold aerosols

    DEFF Research Database (Denmark)

    Schmitt, Regina K.; Pedersen, Liselotte Jauffred; Taheri, S. M.

    2015-01-01

    Aerosol trapping has proven challenging and was only recently demonstrated.1 This was accomplished by utilizing an air chamber designed to have a minimum of turbulence and a laser beam with a minimum of aberration. Individual gold nano-particles with diameters between 80 nm and 200 nm were trapped...... in air using a 1064 nm laser. The positions visited by the trapped gold nano-particle were quantified using a quadrant photo diode placed in the back focal plane. The time traces were analyzed and the trapping stiffness characterizing gold aerosol trapping determined and compared to aerosol trapping...... of nanometer sized silica and polystyrene particles. Based on our analysis, we concluded that gold nano-particles trap more strongly in air than similarly sized polystyrene and silica particles. We found that, in a certain power range, the trapping strength of polystyrene particles is linearly decreasing...

  5. Synthesis, crystal structures, molecular docking and urease inhibition studies of Ni(II) and Cu(II) Schiff base complexes

    Science.gov (United States)

    Sangeeta, S.; Ahmad, K.; Noorussabah, N.; Bharti, S.; Mishra, M. K.; Sharma, S. R.; Choudhary, M.

    2018-03-01

    [Ni(L)2] 1 and [Cu(L)2] 2 [HL = 2-((E)-(2-methoxyphenylimino)methyl)-4,6-dichlorophenol] Schiff base complexes have been successfully synthesized and were characterized by FT-IR, UV-Vis, fluorescence spectroscopy and thermogravimetric analysis. The crystal structures of the two complexes were determined through X-ray crystallography. Its inhibitory activity against Helicobacter pylori urease was evaluated in vitro and showed strong inhibitory activity against H. pylori urease compared with acetohydroxamic acid (IC50 = 42.12 μmolL-1), which is a positive reference. A docking analysis using the AutoDock 4.0 program could explain the inhibitory activity of the complex against urease.

  6. Functional and structural analysis of photosystem II core complexes from spinach with high oxygen evolution capacity

    NARCIS (Netherlands)

    Haag, Elisabeth; Irrgang, Klaus-D.; Boekema, Egbert J.; Renger, Gernot

    1990-01-01

    Oxygen-evolving photo system II core complexes were prepared from spinach by solubilizing photosystem II membrane fragments with dodecyl-β-D-maltoside. The core complexes consist of the intrinsic 47-kDa, 43-kDa, D1 and D2 polypeptides, the two subunits of cytochrome b559 and the extrinsic 33-kDa

  7. Palladium(II)-Stabilized Pyridine-2-Diazotates: Synthesis, Structural Characterization, and Cytotoxicity Studies.

    Science.gov (United States)

    Tskhovrebov, Alexander G; Vasileva, Anna A; Goddard, Richard; Riedel, Tina; Dyson, Paul J; Mikhaylov, Vladimir N; Serebryanskaya, Tatiyana V; Sorokoumov, Viktor N; Haukka, Matti

    2018-02-05

    Well-defined diazotates are scarce. Here we report the synthesis of unprecedented homoleptic palladium(II) diazotate complexes. The palladium(II)-mediated nitrosylation of 2-aminopyridines with NaNO 2 results in the formation of metal-stabilized diazotates, which were found to be cytotoxic to human ovarian cancer cells.

  8. Synthesis of new electroactive polymers by ion-exchange replacement of Mg(II) by 2H+ or Zn(II) cations inside Mg(II) polyporphine film, with their subsequent electrochemical transformation to condensed-structure materials

    International Nuclear Information System (INIS)

    Konev, Dmitry V.; Devillers, Charles H.; Lizgina, Ksenia V.; Zyubina, Tatiana S.; Zyubin, Alexander S.; Maiorova- Valkova, Larisa A.; Vorotyntsev, Mikhail A.

    2014-01-01

    It has been demonstrated that the treatment of the magnesium polyporphine of type I, pMgP-I, by trifluoroacetic acid in acetonitrile may be used to replace initial central Mg(II) cations inside the monomeric macrocycle units by protons, to get a new electroactive polymer, “free-base polyporphine of type I”, pH 2 P-I. In its turn, these inserted protons may be replaced by Zn(II) cations via the film treatment with zinc acetate in organic solvent, to get another new electroactive polymer, “zinc polyporphine of type I”, pZnP-I. These changes of central ions inside monomer units manifest themselves by characteristic modifications of their electroactive properties as well as of UV–visible and IR spectra. Similar to the magnesium polyporphine of type I, pMgP-I, studied in our previous paper (Electrochim. Acta, 2010, 55, 6703) both new polymers are subject to an irreversible electrooxidative transformation into the corresponding polyporphines of type II, pH 2 P-II and pZnP-II. All these polyporphines of type II demonstrate a very broad range of their redox activity, without any potential interval of non-electroactivity. It means that they represent electroactive polymers with a zero-width band gap in the neutral state of the polymer and the Fermi level is located into a broad electronic band for a wide range of the positive and negative oxidation states. Expected molecular structures of all these polymers are discussed

  9. Coordination-organometallic hybrid materials based on the trinuclear M(II)-Ru(II) (M=Ni and Zn) complexes: Synthesis, structural characterization, luminescence and electrochemical properties

    Science.gov (United States)

    Pawal, S. B.; Lolage, S. R.; Chavan, S. S.

    2018-02-01

    A new series of trinuclear complexes of the type Ni[R-C6H4Ndbnd CH(O)C6H3Ctbnd CRu(dppe)2Cl]2 (1a-c) and Zn[Rsbnd C6H4Ndbnd CH(O)C6H3Ctbnd CRu(dppe)2Cl]2 (2a-c) have been prepared from the reaction of trans-[RuCl(dppe)2Ctbnd Csbnd C6H3(OH)(CHO)] (1) with aniline, 4-nitroaniline and 4-methoxyaniline (R1-3) in presence of nickel acetate and zinc acetate in CH2Cl2/MeOH (1:1) mixture. The structural properties of the complexes have been characterized by elemental analyses and spectroscopic techniques viz. FTIR, UV-Visible, 1H NMR and 31P NMR spectral studies. The crystal structure and morphology of the hybrid complexes was investigated with the help of X-ray powder diffraction (XRPD), Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM). The thermal properties of 1a-c and 2a-c were studied by thermogravimetric (TG) analysis. The electrochemical behaviour of the complexes reveals that all complexes displayed a quasireversible redox behaviour corresponding to Ru(II)/Ru(III) and Ni(II)/Ni(III) couples for 1a-c and only Ru(II)/Ru(III) couple for 2a-c. All complexes are emissive in solution at room temperature revealing the influence of substituents and solvent polarity on emission properties of the complexes.

  10. Photonic crystals for light trapping in solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Gjessing, Jo

    2012-07-25

    Solar energy is an abundant and non-polluting source of energy. Nevertheless, the installation of solar cells for energy production is still dependent on subsidies in most parts of the world. One way of reducing the costs of solar cells is to decrease their thickness. This will reduce material consumption and, at the same time, unlock the possibility of using cheaper lower quality solar cell material. However, a thinner solar cell will have a higher optical loss due to insufficient absorption of long wavelength light. Therefore, light-trapping must be improved in order to make thin solar cells economically viable. In this thesis I investigate the potential for light-trapping in thin silicon solar cells by the use of various photonic crystal back-side structures. The first structure I study consists of a periodic array of cylinders in a configuration with a layer of silicon oxide separating the periodic structure from the rear metal reflector. This configuration reduces unwanted parasitic absorption in the reflector and the thickness of the oxide layer provides a new degree of freedom for improving light trapping from the structure. I use a large-period and a small-period approximation to analyze the cylinder structure and to identify criteria that contributes to successful light-trapping. I explore the light-trapping potential of various periodic structures including dimples, inverted pyramids, and cones. The structures are compared in an optical model using a 20 m thick Si slab. I find that the light trapping potential differs between the structures, that the unit cell dimensions for the given structure is more important for light trapping than the type of structure, and that the optimum lattice period does not differ significantly between the different structures. The light-trapping effect of the structures is investigated as a function on incidence angle. The structures provide good light trapping also under angles of incidence up to 60 degrees. The behavior

  11. Photonic crystals for light trapping in solar cells

    International Nuclear Information System (INIS)

    Gjessing, Jo

    2012-01-01

    Solar energy is an abundant and non-polluting source of energy. Nevertheless, the installation of solar cells for energy production is still dependent on subsidies in most parts of the world. One way of reducing the costs of solar cells is to decrease their thickness. This will reduce material consumption and, at the same time, unlock the possibility of using cheaper lower quality solar cell material. However, a thinner solar cell will have a higher optical loss due to insufficient absorption of long wavelength light. Therefore, light-trapping must be improved in order to make thin solar cells economically viable. In this thesis I investigate the potential for light-trapping in thin silicon solar cells by the use of various photonic crystal back-side structures. The first structure I study consists of a periodic array of cylinders in a configuration with a layer of silicon oxide separating the periodic structure from the rear metal reflector. This configuration reduces unwanted parasitic absorption in the reflector and the thickness of the oxide layer provides a new degree of freedom for improving light trapping from the structure. I use a large-period and a small-period approximation to analyze the cylinder structure and to identify criteria that contributes to successful light-trapping. I explore the light-trapping potential of various periodic structures including dimples, inverted pyramids, and cones. The structures are compared in an optical model using a 20 m thick Si slab. I find that the light trapping potential differs between the structures, that the unit cell dimensions for the given structure is more important for light trapping than the type of structure, and that the optimum lattice period does not differ significantly between the different structures. The light-trapping effect of the structures is investigated as a function on incidence angle. The structures provide good light trapping also under angles of incidence up to 60 degrees. The behavior

  12. Structure and dynamics of solvated Ba(II) in dilute aqueous solution - an ab initio QM/MM MD approach

    International Nuclear Information System (INIS)

    Hofer, Thomas S.; Rode, Bernd M.; Randolf, Bernhard R.

    2005-01-01

    Structural properties of the hydrated Ba(II) ion have been investigated by ab initio quantum mechanical/molecular mechanical (QM/MM) molecular dynamics (MD) simulations at double zeta HF quantum mechanical level. The first shell coordination number was found to be 9.3, and several other structural parameters such as angular distribution functions, radial distribution functions and tilt- and θ-angle distributions allowed the full characterization of the hydration structure of the Ba(II) ion in dilute aqueous solution. Velocity autocorrelation functions were used to calculate librational and vibrational motions, ion-ligand motions as well as reorientation times. Different dynamical parameters such as water reorientation, mean ligand residence time, the number of ligand exchange processes and rate constants were also analyzed and the ligand exchange rate constant for the first shell was determined as k = 5.3 x 10 10 s -1

  13. Structural elucidation of the polysaccharide moiety of a glycopeptide (GLPCW-II) from Ganoderma lucidum fruiting bodies.

    Science.gov (United States)

    Ye, LiBin; Zhang, JingSong; Ye, XiJun; Tang, QingJiu; Liu, YanFang; Gong, ChunYu; Du, XiuJui; Pan, YingJie

    2008-03-17

    A water-soluble glycopeptide (GLPCW-II) was isolated from the fruiting bodies of Ganoderma lucidum by DEAE-Sepharose Fast-Flow and Sephacryl S-300 High Resolution Chromatography. The glycopeptide had a molecular weight of 1.2x10(4)Da (determined by HPLC), and consisted of approximately 90% carbohydrate and approximately 8% protein as determined using the phenol-sulfuric acid method and the BCA protein assay reagent kit, respectively. The polysaccharide moiety was composed mainly of D-Glc, L-Fuc, and D-Gal in the ratio of 1.00:1.09:4.09. To facilitate structure-activity studies, the structure of the GLPCW-II polysaccharide moiety was elucidated using 1H and 13C NMR spectroscopy including COSY, TOCSY, HMBC, HSQC, and ROESY, combined with GC-MS of methylated derivatives, and shown to consist of repeating units with the following structure: [Formula: see text].

  14. DIRECT TUNNELLING AND MOSFET BORDER TRAPS

    Directory of Open Access Journals (Sweden)

    Vladimir Drach

    2015-09-01

    Full Text Available The border traps, in particular slow border traps, are being investigated in metal-oxide-semiconductor structures, utilizing n-channel MOSFET as a test sample. The industrial process technology of test samples manufacturing is described. The automated experimental setup is discussed, the implementation of the experimental setup had made it possible to complete the entire set of measurements. The schematic diagram of automated experimental setup is shown. The charging time characteristic of the ID-VG shift reveals that the charging process is a direct tunnelling process and highly bias dependent.

  15. Telomerase Repeated Amplification Protocol (TRAP).

    Science.gov (United States)

    Mender, Ilgen; Shay, Jerry W

    2015-11-20

    Telomeres are found at the end of eukaryotic linear chromosomes, and proteins that bind to telomeres protect DNA from being recognized as double-strand breaks thus preventing end-to-end fusions (Griffith et al. , 1999). However, due to the end replication problem and other factors such as oxidative damage, the limited life span of cultured cells (Hayflick limit) results in progressive shortening of these protective structures (Hayflick and Moorhead, 1961; Olovnikov, 1973). The ribonucleoprotein enzyme complex telomerase-consisting of a protein catalytic component hTERT and a functional RNA component hTR or hTERC - counteracts telomere shortening by adding telomeric repeats to the end of chromosomes in ~90% of primary human tumors and in some transiently proliferating stem-like cells (Shay and Wright, 1996; Shay and Wright, 2001). This results in continuous proliferation of cells which is a hallmark of cancer. Therefore, telomere biology has a central role in aging, cancer progression/metastasis as well as targeted cancer therapies. There are commonly used methods in telomere biology such as Telomere Restriction Fragment (TRF) (Mender and Shay, 2015b), Telomere Repeat Amplification Protocol (TRAP) and Telomere dysfunction Induced Foci (TIF) analysis (Mender and Shay, 2015a). In this detailed protocol we describe Telomere Repeat Amplification Protocol (TRAP). The TRAP assay is a popular method to determine telomerase activity in mammalian cells and tissue samples (Kim et al. , 1994). The TRAP assay includes three steps: extension, amplification, and detection of telomerase products. In the extension step, telomeric repeats are added to the telomerase substrate (which is actually a non telomeric oligonucleotide, TS) by telomerase. In the amplification step, the extension products are amplified by the polymerase chain reaction (PCR) using specific primers (TS upstream primer and ACX downstream primer) and in the detection step, the presence or absence of telomerase is

  16. Atlas of fine structures of dynamic spectra of solar type IV-dm and some type II radio bursts

    International Nuclear Information System (INIS)

    Slottje, C.

    1982-01-01

    The author presents an atlas of spectral fine structures of solar radio bursts of types IV and II around 1 m wavelength, as obtained with a multichannel spectrograph at Dwingeloo. The structures form largely a collection of observations of these events during late 1968 through 1974, thus covering almost entirely the declining branch of solar cycle 20. The spectrograph has an extra enhanced contrast output with properties quite different from those of the commonly used swept frequency spectrographs. The corresponding instrumental characteristics and effects are discussed. A classification of fine structures and an analysis of their statistical properties and of those of the pertinent radio events are also given. (Auth.)

  17. Exploring the water-binding pocket of the type II dehydroquinase enzyme in the structure-based design of inhibitors.

    Science.gov (United States)

    Blanco, Beatriz; Sedes, Antía; Peón, Antonio; Otero, José M; van Raaij, Mark J; Thompson, Paul; Hawkins, Alastair R; González-Bello, Concepción

    2014-04-24

    Structural and computational studies to explore the WAT1 binding pocket in the structure-based design of inhibitors against the type II dehydroquinase (DHQ2) enzyme are reported. The crystal structures of DHQ2 from M. tuberculosis in complex with four of the reported compounds are described. The electrostatic interaction observed between the guanidinium group of the essential arginine and the carboxylate group of one of the inhibitors in the reported crystal structures supports the recently suggested role of this arginine as the residue that triggers the release of the product from the active site. The results of the structural and molecular dynamics simulation studies revealed that the inhibitory potency is favored by promoting interactions with WAT1 and the residues located within this pocket and, more importantly, by avoiding situations where the ligands occupy the WAT1 binding pocket. The new insights can be used to advantage in the structure-based design of inhibitors.

  18. Escaping the tolerance trap

    International Nuclear Information System (INIS)

    Hammoudeh, S.; Madan, V.

    1994-01-01

    In order to examine the implications of the weakening of OPEC's responsiveness in adjusting its production levels, this paper explicitly incorporates rigidity in the quantity adjustment mechanism, thereby extending previous research which assumed smooth quantity adjustments. The rigidity is manifested in a tolerance range for the discrepancy between the declared target price and that of the market. This environment gives rise to a 'tolerance trap' which impedes the convergence process and inevitably brings the market to a standstill before its reaches the targeted price and revenue objectives. OPEC's reaction to the standstill has important implications for the achievement of the target-based equilibrium and for the potential collapse of the market price. This paper examines OPEC's policy options in the tolerance trap and reveals that the optional policy in order to break this impasse and move closer to the equilibrium point is gradually to reduce output and not to flood the market. (Author)

  19. Trapped Ion Qubits

    Energy Technology Data Exchange (ETDEWEB)

    Maunz, Peter Lukas Wilhelm

    2017-04-01

    Qubits can be encoded in clock states of trapped ions. These states are well isolated from the environment resulting in long coherence times [1] while enabling efficient high-fidelity qubit interactions mediated by the Coulomb coupled motion of the ions in the trap. Quantum states can be prepared with high fidelity and measured efficiently using fluorescence detection. State preparation and detection with 99.93% fidelity have been realized in multiple systems [1,2]. Single qubit gates have been demonstrated below rigorous fault-tolerance thresholds [1,3]. Two qubit gates have been realized with more than 99.9% fidelity [4,5]. Quantum algorithms have been demonstrated on systems of 5 to 15 qubits [6–8].

  20. Synthesis, structure, DNA binding and anticancer activity of mixed ligand ruthenium(II) complex

    Science.gov (United States)

    Gilewska, Agnieszka; Masternak, Joanna; Kazimierczuk, Katarzyna; Trynda, Justyna; Wietrzyk, Joanna; Barszcz, Barbara

    2018-03-01

    In order to obtain a potential chemotherapeutic which is not affected on the normal BALB/3T3 cell line, a new arene ruthenium(II) complex {[RuCl(L1)(η6-p-cymene)]PF6}2 · H2O has been synthesized by a direct reaction of precursor, [{(η6-p-cymene)Ru(μ-Cl)}2Cl2], with N,N-chelating ligand (L1 - 2,2‧-bis(4,5-dimethylimidazole). The compound has been fully characterized by elemental analysis, X-ray diffraction, IR, UV-Vis and 1H, 13C NMR spectroscopies. X-ray analysis have confirmed that the compound crystallized in the monoclinic group Cc as an inversion twin. The asymmetric unit contains two symmetrically independent cationic complexes [RuCl(L1)(η6-p-cymene)]+ whose charge is balanced by two PF6- counterions. The shape of each cationic coordination polyhedral can be described as a distorted dodecahedron and shows a typical piano-stool geometry. In addition, an analysis of the crystal structure and the Hirshfeld surface analysis were used to detect and visualize important hydrogen bonds and intermolecular interaction. Moreover, the antiproliferative behavior of the obtained complex was assayed against three human cells: MV-4-11, LoVo, MCF-7 and BALB/3T3 - normal mice fibroblast cells. To predict a binding mode, a potential interaction of ruthenium complex with calf thymus DNA (CT-DNA) has been explored using UV absorption and circular dichroism (CD).

  1. Sediment Trapping in Estuaries

    Science.gov (United States)

    Burchard, Hans; Schuttelaars, Henk M.; Ralston, David K.

    2018-01-01

    Estuarine turbidity maxima (ETMs) are generated by a large suite of hydrodynamic and sediment dynamic processes, leading to longitudinal convergence of cross-sectionally integrated and tidally averaged transport of cohesive and noncohesive suspended particulate matter (SPM). The relative importance of these processes for SPM trapping varies substantially among estuaries depending on topography, fluvial and tidal forcing, and SPM composition. The high-frequency dynamics of ETMs are constrained by interactions with the low-frequency dynamics of the bottom pool of easily erodible sediments. Here, we use a transport decomposition to present processes that lead to convergent SPM transport, and review trapping mechanisms that lead to ETMs at the landward limit of the salt intrusion, in the freshwater zone, at topographic transitions, and by lateral processes within the cross section. We use model simulations of example estuaries to demonstrate the complex concurrence of ETM formation mechanisms. We also discuss how changes in SPM trapping mechanisms, often caused by direct human interference, can lead to the generation of hyperturbid estuaries.

  2. Rare azido-bridged manganese(II) systems: syntheses, crystal structures, and magnetic properties.

    Science.gov (United States)

    Ghosh, A K; Ghoshal, D; Zangrando, E; Ribas, J; Ray Chaudhuri, N

    2005-03-21

    Two new polymeric azido-bridged manganese complexes of formulas [Mn(N3)2 (bpee)]n (1) and {[Mn(N3)(dpyo)Cl(H2O)2](H2O)}n (2) [bpee, trans-1,2-bis(4-pyridyl)ethylene; dpyo, 4,4'-dipyridyl N,N'-dioxide] have been synthesized and characterized by single-crystal X-ray diffraction analysis and low-temperature magnetic study. Both the complexes 1 and 2 crystallize in the triclinic system, space group P1, with a = 8.877(3) A, b = 11.036(3) A, c = 11.584(4) A, alpha = 72.62(2) degrees, beta = 71.06(2) degrees, gamma = 87.98(3) degrees, and Z = 1 and a = 7.060(3) A, b = 10.345(3) A, c = 11.697(4) A, alpha = 106.86(2) degrees, beta = 113.33(2) degrees, gamma = 96.39(3) degrees, and Z = 2, respectively. Complex 1 exhibits a 2D structure of [-Mn(N3)2-]n chains, connected by bpee ligands, whose pyridine rings undergo pi-pi and C-H...pi interactions. This facilitates the rare arrangement of doubly bridged azide ligands with one end-on and two end-to-end (EO-EE-EE) sequence. Complex 2 is a neutral 1D polymer built up by [Mn(N3)(dpyo)Cl(H2O)2] units and lattice water molecules. The metals are connected by single EE azide ligands, which are arranged in a cis position to the Mn(II) center. The 1D zipped chains are linked by H-bonds involving lattice water molecules and show pi-pi stacking of dpyo pyridine rings to form a supramolecular 2D layered structure. The magnetic studies were performed in 2-300 K temperature range, and the data were fitted by considering an alternating chain of exchange interactions with S = 5/2 (considered as classical spin) with the spin Hamiltonians H = -Ji sigma(S(3i)S(3i+1) + S(3i+1)S(3i+2)) - J2 sigmaS(3i-1)S(3i) and H = -Ji sigmaS(2i)S(2i+1) - J2 sigmaS(2i+1)S(2i+2) for complexes 1 and 2, respectively. Complex 2 exhibits small antiferromagnetic coupling between the metal centers, whereas 1 exhibits a new case of topological ferromagnetism, which is very unusual.

  3. Measuring sunscreen protection against solar-simulated radiation-induced structural radical damage to skin using ESR/spin trapping: development of an ex vivo test method.

    Science.gov (United States)

    Haywood, Rachel; Volkov, Arsen; Andrady, Carima; Sayer, Robert

    2012-03-01

    The in vitro star system used for sunscreen UVA-testing is not an absolute measure of skin protection being a ratio of the total integrated UVA/UVB absorption. The in vivo persistent-pigment-darkening method requires human volunteers. We investigated the use of the ESR-detectable DMPO protein radical-adduct in solar-simulator-irradiated skin substitutes for sunscreen testing. Sunscreens SPF rated 20+ with UVA protection, reduced this adduct by 40-65% when applied at 2 mg/cm(2). SPF 15 Organic UVA-UVB (BMDBM-OMC) and TiO(2)-UVB filters and a novel UVA-TiO(2) filter reduced it by 21, 31 and 70% respectively. Conventional broad-spectrum sunscreens do not fully protect against protein radical-damage in skin due to possible visible-light contributions to damage or UVA-filter degradation. Anisotropic spectra of DMPO-trapped oxygen-centred radicals, proposed intermediates of lipid-oxidation, were detected in irradiated sunscreen and DMPO. Sunscreen protection might be improved by the consideration of visible-light protection and the design of filters to minimise radical leakage and lipid-oxidation.

  4. A Pneumatic Actuated Microfluidic Beads-Trapping Device

    Energy Technology Data Exchange (ETDEWEB)

    Shao, Guocheng; Cai, Ziliang; Wang, Jun; Wang, Wanjun; Lin, Yuehe

    2011-08-20

    The development of a polydimethylsiloxane (PDMS) microfluidic microbeads trapping device is reported in this paper. Besides fluid channels, the proposed device includes a pneumatic control chamber and a beads-trapping chamber with a filter array structure. The pneumatic flow control chamber and the beads-trapping chamber are vertically stacked and separated by a thin membrane. By adjusting the pressure in the pneumatic control chamber, the membrane can either be pushed against the filter array to set the device in trapping mode or be released to set the device in releasing mode. In this paper, a computational fluid dynamics simulation was conducted to optimize the geometry design of the filter array structure; the device fabrication was also carried out. The prototype device was tested and the preliminary experimental results showed that it can be used as a beads-trapping unit for various biochemistry and analytical chemistry applications, especially for flow injection analysis systems.

  5. Space Qualified Non-Destructive Evaluation and Structural Health Monitoring Technology, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Encouraged by Phase I accomplishments, the proposed Phase II program will significantly mature and align the development of a Space Qualified Non-Destructive...

  6. Hyperfine interactions and structures of ferrous hydroxide and green rust II in sulfated aqueous media

    International Nuclear Information System (INIS)

    Olowe, A.A.; Genin, J.M.R.; Bauer, P.

    1988-01-01

    A sulfated ferrous hydroxide is obtained by mixing NaOH with melanterite depending on the R = [SO 4 -- ]/[OH - ] ratio and leading by oxidation to the green rust II transient compound. Hyperfine parameters are presented. (orig.)

  7. An EPR study of positive hole transfer and trapping in irradiated frozen solutions containing aromatic traps

    International Nuclear Information System (INIS)

    Egorov, A.V.; Zezin, A.A.; Feldman, V.I.

    2002-01-01

    Complete text of publication follows. Processes of positive hole migration and trapping are of basic significance for understanding of the primary events in the radiation chemistry of solid molecular systems. Specific interest is concerned with the case, when ionization energies of 'hole traps' are rather close, so one may expect 'fine tuning' effects resulting from variations in conformation, weak interactions, molecular packing, etc. In this contribution we report the results of EPR study of formation of radical cations in irradiated frozen halocarbon solutions containing aromatic molecules of different structure. Using the 'two-trap' model made it possible to obtain an evidence for efficient long-range trap-to-trap positive hole transfer between alkyl benzene molecules with close ionization energies distributed in the matrices with high ionization potentials. The distance of transfer was found to be 2-4 nm. In the case of frozen solutions containing ethylbenzene and toluene, it was found that the efficiency and direction of hole transfer was controlled by the conformation of ethylbenzene radical cation. The study of positive hole localization in 'bridged' diphenyls of Ph(CH 2 ) n Ph type revealed that the structure of radical cations of these species was affected by local environment (type of halocarbon matrix) and the conformational flexibility of 'bridge'. In summary, we may conclude that migration and localization of positive hole in rigid systems containing aromatic 'traps' is quite sensitive to rather subtle effects. This conclusion may be of common significance for the radiation chemistry of systems with physical dispersion of the traps of similar chemical structure (e.g. macromolecules, adsorbed molecules, etc.)

  8. Multipole electrodynamic ion trap geometries for microparticle confinement under standard ambient temperature and pressure conditions

    Energy Technology Data Exchange (ETDEWEB)

    Mihalcea, Bogdan M., E-mail: bogdan.mihalcea@inflpr.ro; Vişan, Gina T.; Ganciu, Mihai [National Institute for Laser, Plasma and Radiation Physics (INFLPR), Atomiştilor Str. Nr. 409, 077125 Măgurele, Ilfov (Romania); Giurgiu, Liviu C. [University of Bucharest, Faculty of Physics, Atomistilor Str. Nr. 405, 077125 Măgurele (Romania); Stan, Cristina [Department of Physics, Politehnica University, 313 Splaiul Independenţei, RO-060042 Bucharest (Romania); Filinov, Vladimir; Lapitsky, Dmitry, E-mail: dmitrucho@yandex.ru; Deputatova, Lidiya; Syrovatka, Roman [Joint Institute for High Temperatures, Russian Academy of Sciences, Izhorskaya Str. 13, Bd. 2, 125412 Moscow (Russian Federation)

    2016-03-21

    Trapping of microparticles and aerosols is of great interest for physics and chemistry. We report microparticle trapping in case of multipole linear Paul trap geometries, operating under standard ambient temperature and pressure conditions. An 8- and 12-electrode linear trap geometries have been designed and tested with an aim to achieve trapping for larger number of particles and to study microparticle dynamical stability in electrodynamic fields. We report emergence of planar and volume ordered structures of microparticles, depending on the a.c. trapping frequency and particle specific charge ratio. The electric potential within the trap is mapped using the electrolytic tank method. Particle dynamics is simulated using a stochastic Langevin equation. We emphasize extended regions of stable trapping with respect to quadrupole traps, as well as good agreement between experiment and numerical simulations.

  9. Multipole electrodynamic ion trap geometries for microparticle confinement under standard ambient temperature and pressure conditions

    International Nuclear Information System (INIS)

    Mihalcea, Bogdan M.; Vişan, Gina T.; Ganciu, Mihai; Giurgiu, Liviu C.; Stan, Cristina; Filinov, Vladimir; Lapitsky, Dmitry; Deputatova, Lidiya; Syrovatka, Roman

    2016-01-01

    Trapping of microparticles and aerosols is of great interest for physics and chemistry. We report microparticle trapping in case of multipole linear Paul trap geometries, operating under standard ambient temperature and pressure conditions. An 8- and 12-electrode linear trap geometries have been designed and tested with an aim to achieve trapping for larger number of particles and to study microparticle dynamical stability in electrodynamic fields. We report emergence of planar and volume ordered structures of microparticles, depending on the a.c. trapping frequency and particle specific charge ratio. The electric potential within the trap is mapped using the electrolytic tank method. Particle dynamics is simulated using a stochastic Langevin equation. We emphasize extended regions of stable trapping with respect to quadrupole traps, as well as good agreement between experiment and numerical simulations.

  10. Al2O3 influence on structural, elastic, thermal properties of Yb(3+) doped Ba-La-tellurite glass: evidence of reduction in self-radiation trapping at 1μm emission.

    Science.gov (United States)

    Balaji, S; Biswas, K; Sontakke, A D; Gupta, G; Ghosh, D; Annapurna, K

    2014-12-10

    Ba-La-tellurite glasses doped with Yb(3+) ions have been prepared through melt quenching technique by modifying their composition with the inclusion of varied concentration of Al2O3 to elucidate its effects on glass structural, elastic, thermal properties and Yb(3+) ion NIR luminescence performance. The FTIR spectral analysis indicates Al2O3 addition is promoting the conversion of BOs from NBOs which have been generated during the process of depolymerisation of main glass forming TeO4 units. The elastic properties of the glass revealed an improved rigidity of the glass network on addition of Al2O3. In concurrence to this, differential thermal analysis showed an increase in glass transition temperature with improved thermal stability factor. Also, Yb(3+) fluorescence dynamics demonstrated that, Al2O3 inclusion helps in restraining the detrimental radiation trapping of ∼1μm emission. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Synthesis, crystal structures, spectral, thermal and antimicrobial properties of new Zn(II) 5-iodo- and 5-bromosalicylates

    Science.gov (United States)

    Košická, Petra; Győryová, Katarína; Smolko, Lukáš; Gyepes, Róbert; Hudecová, Daniela

    2018-03-01

    Two new analogous zinc(II) complexes containing 5-iodo- and 5-bromosalicylate ligands, respectively, were prepared in single-crystal form and characterized by IR spectroscopy, thermal analysis and elemental analysis. The solid-state structures of prepared complexes were determined by single crystal X-ray crystallography. Both complexes are isostructural and their crystal structures composed of neutral molecules [Zn(5-Xsal)2(H2O)2] (where X = Br, I, sal = salicylato). Central Zn(II) atom is in both complexes coordinated by six oxygen atoms, four of which are from two chelate bonded 5-halosalicylates and remaining two from coordinated water molecules. The found chelate binding mode is in line with the Δ values calculated from IR spectral data. Antimicrobial activity of prepared complexes was studied against selected bacteria, yeast and filamentous fungi. Obtained results indicate that 5-iodosalicylate complex is more antimicrobially active than its 5-bromo substituted analogue.

  12. Structural basis of carbohydrate recognition by lectin II from Ulex europaeus, a protein with a promiscuous carbohydrate-binding site.

    Science.gov (United States)

    Loris, R; De Greve, H; Dao-Thi, M H; Messens, J; Imberty, A; Wyns, L

    2000-08-25

    Protein-carbohydrate interactions are the language of choice for inter- cellular communication. The legume lectins form a large family of homologous proteins that exhibit a wide variety of carbohydrate specificities. The legume lectin family is therefore highly suitable as a model system to study the structural principles of protein-carbohydrate recognition. Until now, structural data are only available for two specificity families: Man/Glc and Gal/GalNAc. No structural data are available for any of the fucose or chitobiose specific lectins. The crystal structure of Ulex europaeus (UEA-II) is the first of a legume lectin belonging to the chitobiose specificity group. The complexes with N-acetylglucosamine, galactose and fucosylgalactose show a promiscuous primary binding site capable of accommodating both N-acetylglucos amine or galactose in the primary binding site. The hydrogen bonding network in these complexes can be considered suboptimal, in agreement with the low affinities of these sugars. In the complexes with chitobiose, lactose and fucosyllactose this suboptimal hydrogen bonding network is compensated by extensive hydrophobic interactions in a Glc/GlcNAc binding subsite. UEA-II thus forms the first example of a legume lectin with a promiscuous binding site and illustrates the importance of hydrophobic interactions in protein-carbohydrate complexes. Together with other known legume lectin crystal structures, it shows how different specificities can be grafted upon a conserved structural framework. Copyright 2000 Academic Press.

  13. Synthesis, crystal structure, fluorescence and electrochemical studies of a new tridentate Schiff base ligand and its nickel(II) and palladium(II) complexes

    Science.gov (United States)

    Shafaatian, Bita; Soleymanpour, Ahmad; Kholghi Oskouei, Nasim; Notash, Behrouz; Rezvani, Seyyed Ahmad

    2014-07-01

    A new unsymmetrical tridentate Schiff base ligand was derived from the 1:1 M condensation of ortho-vanillin with 2-mercaptoethylamine. Nickel and palladium complexes were obtained by the reaction of the tridentate Schiff base ligand with nickel(II) acetate tetrahydrate and palladium(II) acetate in 2:1 M ratio. In nickel and palladium complexes the ligand was coordinated to metals via the imine N and enolic O atoms. The S groups of Schiff bases were not coordinated to the metals and S-S coupling was occured. The complexes have been found to possess 1:2 Metal:Ligand stoichiometry and the molar conductance data revealed that the metal complexes were non-electrolytes. The complexes exhibited octahedral coordination geometry. The emission spectra of the ligand and its complexes were studied in methanol. Electrochemical properties of the ligand and its metal complexes were investigated in the CH3CN solvent at the 100 mV s-1 scan rate. The ligand and metal complexes showed both reversible and quasi-reversible processes at this scan rate. The Schiff base and its complexes have been characterized by IR, 1H NMR, UV/Vis, elemental analyses and conductometry. The crystal structure of nickel complex has been determined by single crystal X-ray diffraction.

  14. New fluorescent azo-Schiff base Cu(II) and Zn(II) metal chelates; spectral, structural, electrochemical, photoluminescence and computational studies

    Science.gov (United States)

    Purtas, Fatih; Sayin, Koray; Ceyhan, Gokhan; Kose, Muhammet; Kurtoglu, Mukerrem

    2017-06-01

    A new Schiff base containing azo chromophore group obtained by condensation of 2-hydroxy-4-[(E)-phenyldiazenyl]benzaldehyde with 3,4-dimethylaniline (HL) are used for the syntheses of new copper(II) and zinc(II) chelates, [Cu(L)2], and [Zn(L)2], and characterized by physico-chemical and spectroscopic methods such as 1H and 13C NMR, IR, UV.-Vis. and elemental analyses. The solid state structure of the ligand was characterized by single crystal X-ray diffraction study. X-ray diffraction data was then used to calculate the harmonic oscillator model of aromaticity (HOMA) indexes for the rings so as to investigate of enol-imine and keto-amine tautomeric forms in the solid state. The phenol ring C10-C15 shows a considerable deviation from the aromaticity with HOMA value of 0.837 suggesting the shift towards the keto-amine tautomeric form in the solid state. The analytical data show that the metal to ligand ratio in the chelates was found to be 1:2. Theoretical calculations of the possible isomers of the ligand and two metal complexes are performed by using B3LYP method. Electrochemical and photoluminescence properties of the synthesized azo-Schiff bases were also investigated.

  15. Performance improvement of charge trap flash memory by using a composition-modulated high-k trapping layer

    International Nuclear Information System (INIS)

    Tang Zhen-Jie; Li Rong; Yin Jiang

    2013-01-01

    A composition-modulated (HfO 2 ) x (Al 2 O3) 1−x charge trapping layer is proposed for charge trap flash memory by controlling the Al atom content to form a peak and valley shaped band gap. It is found that the memory device using the composition-modulated (HfO 2 ) x (Al 2 O 3 ) 1−x as the charge trapping layer exhibits a larger memory window of 11.5 V, improves data retention even at high temperature, and enhances the program/erase speed. Improvements of the memory characteristics are attributed to the special band-gap structure resulting from the composition-modulated trapping layer. Therefore, the composition-modulated charge trapping layer may be useful in future nonvolatile flash memory device application. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  16. Structural myocardial changes in chronic heart failure of II functional class based on overweight and abdominal obesity

    Directory of Open Access Journals (Sweden)

    V. Z. Netyazhenko

    2014-04-01

    Full Text Available Abstract. 153 patients with CHF of II functional class, with normal weight, overweight and abdominal obesity I-III degrees Examined. Studied structural myocardial changes at CHF depending on the degree of excess weight. Structural changes of the heart, the extent and type of myocardial hypertrophy of left ventricle depending on the availability of overweight and obesity were revealed. Actuality. Chronic heart failure (CHF is characterized by a high mortality rate and frequency of hospitalization of patients, a significant decline in their quality of life and significant financial burden. CHF is a medical and social problem that a certain dominant in the near future all over the world, because the average life expectancy of patients with the diagnosis ranges from 1,7 to 7 years and the long-term observation is evidence of the increased risk of death, that 5 year more than four times the initial value. The main etiological factors of occurrence, progression and adverse exit of CHF are age, coronary heart disease (CHD, arterial hypertension, valvular heart disease, diabetes and obesity. In general, structural changes of heart in obesity can be divided into the following main components: left ventricle hypertrophy, changes in the structural composition of cardiac tissue, heart obesity, change of the sizes of the right ventricle and left atrium (PL, valvular heart disease. Research objective: to establish the structural changes of CHF of II functional class depending on the availability of overweight and abdominal type of obesity various degrees. Material and methods: 153 patients with CHF of II functional class were examined. Etiological factors of development CHF were hypertensive disease, chronic forms of CAD and the combination of these pathologies. The diagnosis of CHF installed according to WHO criteria, the European society of cardiology and the Association of cardiologists of Ukraine, and classified according to functional classification of

  17. Cd (II) and holodirected lead (II) 3D-supramolecular coordination polymers based on nicotinic acid: Structure, fluorescence property and photocatalytic activity

    Science.gov (United States)

    Etaiw, Safaa El-din H.; Abd El-Aziz, Dina M.; Marie, Hassan; Ali, Elham

    2018-05-01

    Two new supramolecular coordination polymers namely {[Cd(NA)2(H2O)]}, SCP 1 and {[Pb(NA)2]}, SCP 2, (NA = nicotinate ligand) were synthesized by self-assembly method and structurally characterized by different analytical and spectroscopic methods. Single-crystal X-ray diffraction showed that SCP 1 extend in three dimensions containing bore structure where the 3D- network is constructed via interweaving zigzag chains. The Cd atom coordinates to (O4N2) atoms forming distorted-octahedral configuration. The structure of SCP 2 extend down the projection of the b-axis creating parallel zigzag 1D-chains connected by μ2-O2 atoms and H-bonds forming a holodirected lead (II) hexagonal bi-pyramid configuration. SCP 2 extend to 3D-network via coordinate and hydrogen bonds. The thermal stability, photoluminescence properties, photocatalytic activity for the degradation of methylene blue dye (MB) under UV-irradiation and sunlight irradiation were also studied.

  18. Synthesis, structure and magnetic properties of cobalt(II) and copper(II) coordination polymers assembled by phthalate and 4-methylimidazole

    International Nuclear Information System (INIS)

    Baca, S.G.; Malinovskii, S.T.; Franz, Patrick; Ambrus, Christina; Stoeckli-Evans, Helen; Gerbeleu, Nicolae; Decurtins, Silvio

    2004-01-01

    New coordination polymers [M(Pht)(4-MeIm) 2 (H 2 O)] n (M=Co (1), Cu (2); Pht 2- =dianion of o-phthalic acid; 4-MeIm=4-methylimidazole) have been synthesized and characterized by IR spectroscopy, X-ray crystallography, thermogravimetric analysis and magnetic measurements. The crystal structures of 1 and 2 are isostructural and consist of [M(4-MeIm) 2 (H 2 O)] building units linked in infinite 1D helical chains by 1,6-bridging phthalate ions which also act as chelating ligands through two O atoms from one carboxylate group in the case of 1. In complex 1, each Co(II) atom adopts a distorted octahedral N 2 O 4 geometry being coordinated by two N atoms from two 4-MeIm, three O atoms of two phthalate residues and one O atom of a water molecule, whereas the square-pyramidal N 2 O 3 coordination of the Cu(II) atom in 2 includes two N atoms of N-containing ligands, two O atoms of two carboxylate groups from different Pht, and a water molecule. An additional strong O-H↑··O hydrogen bond between a carboxylate group of the phthalate ligand and a coordinated water molecule join the 1D helical chains to form a 2D network in both compounds. The thermal dependences of the magnetic susceptibilities of the polymeric helical Co(II) chain compound 1 were simulated within the temperature range 20-300 K as a single ion case, whereas for the Cu(II) compound 2, the simulations between 25 and 300 K, were made for a linear chain using the Bonner-Fisher approximation. Modelling the experimental data of compound 1 with MAGPACK resulted in: g=2.6, vertical bar D vertical bar=62 cm -1 . Calculations using the Bonner-Fisher approximation gave the following result for compound 2: g=2.18, J=-0.4 cm -1

  19. Stable Trapping of Multielectron Helium Bubbles in a Paul Trap

    Science.gov (United States)

    Joseph, E. M.; Vadakkumbatt, V.; Pal, A.; Ghosh, A.

    2017-06-01

    In a recent experiment, we have used a linear Paul trap to store and study multielectron bubbles (MEBs) in liquid helium. MEBs have a charge-to-mass ratio (between 10^{-4} and 10^{-2} C/kg) which is several orders of magnitude smaller than ions (between 10^6 and 10^8 C/kg) studied in traditional ion traps. In addition, MEBs experience significant drag force while moving through the liquid. As a result, the experimental parameters for stable trapping of MEBs, such as magnitude and frequency of the applied electric fields, are very different from those used in typical ion trap experiments. The purpose of this paper is to model the motion of MEBs inside a linear Paul trap in liquid helium, determine the range of working parameters of the trap, and compare the results with experiments.

  20. Microwave quantum logic gates for trapped ions.

    Science.gov (United States)

    Ospelkaus, C; Warring, U; Colombe, Y; Brown, K R; Amini, J M; Leibfried, D; Wineland, D J

    2011-08-10

    Control over physical systems at the quantum level is important in fields as diverse as metrology, information processing, simulation and chemistry. For trapped atomic ions, the quantized motional and internal degrees of freedom can be coherently manipulated with laser light. Similar control is difficult to achieve with radio-frequency or microwave radiation: the essential coupling between internal degrees of freedom and motion requires significant field changes over the extent of the atoms' motion, but such changes are negligible at these frequencies for freely propagating fields. An exception is in the near field of microwave currents in structures smaller than the free-space wavelength, where stronger gradients can be generated. Here we first manipulate coherently (on timescales of 20 nanoseconds) the internal quantum states of ions held in a microfabricated trap. The controlling magnetic fields are generated by microwave currents in electrodes that are integrated into the trap structure. We also generate entanglement between the internal degrees of freedom of two atoms with a gate operation suitable for general quantum computation; the entangled state has a fidelity of 0.76(3), where the uncertainty denotes standard error of the mean. Our approach, which involves integrating the quantum control mechanism into the trapping device in a scalable manner, could be applied to quantum information processing, simulation and spectroscopy.

  1. Temperature-dependent structural changes in intrinsically disordered proteins: formation of alpha-helices or loss of polyproline II?

    DEFF Research Database (Denmark)

    Kjærgaard, Magnus; Nørholm, Ann-Beth; Hendus-Altenburger, Ruth

    2010-01-01

    temperature, which most likely reflects formation of transient alpha-helices or loss of polyproline II (PPII) content. Using three IDPs, ACTR, NHE1, and Spd1, we show that the temperature-induced structural change is common among IDPs and is accompanied by a contraction of the conformational ensemble...... with increasing temperature, and accordingly these were not responsible for the change in the CD spectra. In contrast, the nonhelical regions exhibited a general temperature-dependent structural change that was independent of long-range interactions. The temperature-dependent CD spectroscopic signature of IDPs...

  2. Structure and dynamics of hydrated Fe(II) and Fe(III) ions. Quantum mechanical and molecular mechanical simulations

    International Nuclear Information System (INIS)

    Remsungnen, T.

    2002-11-01

    Classical molecular dynamics (MD) and combined em ab initio quantum mechanical/molecular mechanical molecular dynamics (QM/MM-MD) simulations have been performed to investigate structural, dynamical and energetical properties of Fe(II), and Fe(III) transition metal ions in aqueous solution. In the QM/MM-MD simulations the ion and its first hydration sphere were treated at the Hartree-Fock ab initio quantum mechanical level, while ab initio generated pair plus three-body potentials were employed for the remaining system. For the classical MD simulation the pair plus three-body potential were employed for all ion-water interactions. The coordination number of the first hydration shell is 100 % of 6 in both cases. The number of waters in the second hydration shell obtained from classical simulations are 13.4 and 15.1 for Fe(II) and Fe(III), respectively, while QM/MM-MD gives the values of 12.4 and 13.4 for Fe(II) and Fe(III). The energies of hydration obtained from MD and QM/MM-MD for Fe(II) are 520 and 500 kcal/mol, and for Fe(III) 1160 and 1100 kcal/mol respectively. The mean residence times of water in the second shell obtained from QM/MM-MD are 24 and 48 ps for Fe(II) and Fe(III), respectively. In contrast to the data obtained from classical MD simulation, the QM/MM-MD values are all in good agreement with the experimental data available. These investigations and results clearly indicate that many-body effects are essential for the proper description of all properties of the aqueous solution of both Fe(II) and Fe(III) ions. (author)

  3. Trapping of light by metal arrays

    Science.gov (United States)

    Khardikov, Vyacheslav V.; Iarko, Ekaterina O.; Prosvirnin, Sergey L.

    2010-04-01

    The problem of the near-IR light reflection from and transmittance through a planar 2D periodic metal-dielectric structure with a square periodic cell of two complex-shaped asymmetric metal elements has been solved. Conditions of the light confinement by excitation of the trapped mode resonances in certain structures, both polarization-sensitive and polarization-insensitive, were studied. For the first time, the existence of a high-order trapped mode resonance with the greater quality factor than that of the lowest one has been shown. It was ascertained that the Babinet principle provides a good prediction of the resonance properties of the complementary structures, despite the very high Joule losses in the metal strips in near-IR, a finite thickness of the metal elements and the presence of a dielectric substrate.

  4. Trapping of light by metal arrays

    International Nuclear Information System (INIS)

    Khardikov, Vyacheslav V; Iarko, Ekaterina O; Prosvirnin, Sergey L

    2010-01-01

    The problem of the near-IR light reflection from and transmittance through a planar 2D periodic metal–dielectric structure with a square periodic cell of two complex-shaped asymmetric metal elements has been solved. Conditions of the light confinement by excitation of the trapped mode resonances in certain structures, both polarization-sensitive and polarization-insensitive, were studied. For the first time, the existence of a high-order trapped mode resonance with the greater quality factor than that of the lowest one has been shown. It was ascertained that the Babinet principle provides a good prediction of the resonance properties of the complementary structures, despite the very high Joule losses in the metal strips in near-IR, a finite thickness of the metal elements and the presence of a dielectric substrate

  5. Atom trap trace analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Z.-T.; Bailey, K.; Chen, C.-Y.; Du, X.; Li, Y.-M.; O' Connor, T. P.; Young, L.

    2000-05-25

    A new method of ultrasensitive trace-isotope analysis has been developed based upon the technique of laser manipulation of neutral atoms. It has been used to count individual {sup 85}Kr and {sup 81}Kr atoms present in a natural krypton sample with isotopic abundances in the range of 10{sup {minus}11} and 10{sup {minus}13}, respectively. The atom counts are free of contamination from other isotopes, elements,or molecules. The method is applicable to other trace-isotopes that can be efficiently captured with a magneto-optical trap, and has a broad range of potential applications.

  6. Atom trap trace analysis

    International Nuclear Information System (INIS)

    Lu, Z.-T.; Bailey, K.; Chen, C.-Y.; Du, X.; Li, Y.-M.; O'Connor, T. P.; Young, L.

    2000-01-01

    A new method of ultrasensitive trace-isotope analysis has been developed based upon the technique of laser manipulation of neutral atoms. It has been used to count individual 85 Kr and 81 Kr atoms present in a natural krypton sample with isotopic abundances in the range of 10 -11 and 10 -13 , respectively. The atom counts are free of contamination from other isotopes, elements,or molecules. The method is applicable to other trace-isotopes that can be efficiently captured with a magneto-optical trap, and has a broad range of potential applications

  7. A Novel 3D Printer to Support Additive Manufacturing of Gradient Metal Alloy Structures, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Gradient metal alloy structures possess multi-functional properties that conventional monolithic metal counterparts do not have. Such structures can potentially...

  8. Red trap colour of the carnivorous plant Drosera rotundifolia does not serve a prey attraction or camouflage function.

    Science.gov (United States)

    Foot, G; Rice, S P; Millett, J

    2014-01-01

    The traps of many carnivorous plants are red in colour. This has been widely hypothesized to serve a prey attraction function; colour has also been hypothesized to function as camouflage, preventing prey avoidance. We tested these two hypotheses in situ for the carnivorous plant Drosera rotundifolia. We conducted three separate studies: (i) prey attraction to artificial traps to isolate the influence of colour; (ii) prey attraction to artificial traps on artificial backgrounds to control the degree of contrast and (iii) observation of prey capture by D. rotundifolia to determine the effects of colour on prey capture. Prey were not attracted to green traps and were deterred from red traps. There was no evidence that camouflaged traps caught more prey. For D. rotundifolia, there was a relationship between trap colour and prey capture. However, trap colour may be confounded with other leaf traits. Thus, we conclude that for D. rotundifolia, red trap colour does not serve a prey attraction or camouflage function.

  9. Structural and antimicrobial studies of coordination compounds of VO(II, Co(II, Ni(II and Cu(II with some Schiff bases involving 2-amino-4-chlorophenol

    Directory of Open Access Journals (Sweden)

    A. P. MISHRA

    2009-05-01

    Full Text Available Complexes of tailor-made ligands with life essential metal ions may be an emerging area to answer the problem of multi-drug resistance (MDR. The coordination complexes of VO(II, Co(II, Ni(II and Cu(II with the Schiff bases derived from 2-hydroxyacetophenone/2-chlorobenzaldehyde with 2-ami¬no-4-chlorophenol were synthesized and characterized by elemental analysis, molar conductance, electronic spectra, FT-IR, ESR, FAB mass, thermal and magnetic susceptibility measurements. The FAB mass and thermal data show degradation of the complexes. The ligand A (2-hydroxyacetophenone-2amino-4-chlorophenol behaved as tridentate and ligand B (2-chlorobenzylidene-2-amino-4-chlorophenol as bidentate, coordinating through O and N donors. The complexes [VO(A(H2O]×xH2O, [M(A(H2On]×xH2O for Co and Ni, [Cu(A(H2O] and [VO(B2]×xH2O, [M(B2(H2On] for Co and Cu and [Ni(B2] exhibited coordination numbers 4, 5 or 6. X-ray powder diffraction data (a = 11.00417 Å, b = 11.706081 Å and c = 54.46780 Å showed that [Cu(CACP2(H2O2], complex 8, crystallized in the orthorhombic system. The in vitro biological screening effects of the investigated compounds were tested against the bacteria Escherichia coli, Staphylococcus aureus and Streptococcus fecalis and the fungi Aspergillus niger, Trichoderma polysporum and Candida albicans by the serial dilution method. A comparative study of the MIC values of the Schiff base and their [M(B2(H2O2] complexes (Co(II, complex 6 and Cu(II, complex 8, indicated that the metal complexes exhibited a higher or lower antimicrobial activity than 2-chlorobenzylidene-2-amino-4-chlorophenol as the free ligand (B.

  10. Seven new Zn(II)/Cd(II) coordination polymers with 2-(hydroxymethyl)-1H-benzo[d]imidazole-5-carboxylic acid: Synthesis, structures and properties

    Science.gov (United States)

    Wang, Xin-Fang; Zhou, Sheng-Bin; Du, Ceng-Ceng; Wang, Duo-Zhi; Jia, Dianzeng

    2017-08-01

    Using a new simi-rigid multitopic ligand 2-(hydroxymethyl)-1H-benzo[d]imidazole-5-carboxylic acid (H2L), seven new coordination polymers [Zn3(L)2(μ2-OH)2]n (1), {[Zn2(HL)2(H2O)2]·SiF6}n (2), [Zn(HL)(SCN)]n (3), {[Zn2(HL)2(SO4)]·(4,4‧-bpy)}n (4) [4,4‧-bpy =4,4‧-bipyridine], {[Zn(HL)2]·2H2O}n (5), {[Cd(HL)2]·2H2O}n (6) and [Cd2(HL)2(H2O)2(SO4)]n (7) have been successfully obtained from H2L ligand under solvothermal conditions and structurally characterized by single-crystal X-ray diffraction, elemental analysis, thermogravimetric analysis, powder X-ray diffraction and IR spectroscopy. In addition, UV-vis diffuse-reflectance spectra demonstrate wide band gaps. Complex 1 features a 3D topological net of {412·63} with the stoichiometry (6-c), contains 1D channels with the accessible solvent volume of 42.1%. 3, 4, 5 and 6 have a 1D chain structure, 5 and 6 further assemble to form 2D sheet and 3D supramolecular frameworks by hydrogen-bonding interactions, respectively. Complexes 2 and 7 possess a 2D layered structure, and the 2D supramolecular network of 2 can be rationalized to be four-connected {44·62} topological sql network with the dinuclear units, while 7 shows a 3-nodal 2D net with a point symbol of {63}. Moreover, the fluorescent emission, fluorescence lifetimes of 1-7 have been investigated and discussed. Interesting enough, complex 1 showed high efficiency for catalyzing the Knoevenagel condensation reaction between 4-substituted aromatic aldehydes and malononitrile as selective heterogeneous catalyst. The CPs combining catalytic and fluorescent properties could further meet the requirement as a multifunctional material. Seven new Zn(II)/Cd(II) coordination polymers with simi-rigid multitopic ligand, [(2-(hydroxymethyl)-1H-benzo[d]imidazole-5-carboxylic acid) (H2L)] have been successfully obtained and structurally characterized by single-crystal X-ray diffraction, elemental analysis, thermogravimetric analysis, powder X-ray diffraction and IR

  11. EBR-II Cover Gas Cleanup System upgrade process control system structure

    International Nuclear Information System (INIS)

    Carlson, R.B.; Staffon, J.D.

    1992-01-01

    The Experimental Breeder Reactor II (EBR-II) Cover Gas Cleanup System (CGCS) control system was upgraded in 1991 to improve control and provide a graphical operator interface. The upgrade consisted of a main control computer, a distributed control computer, a front end input/output computer, a main graphics interface terminal, and a remote graphics interface terminal. This paper briefly describes the Cover Gas Cleanup System and the overall control system; describes the main control computer hardware and system software features in more detail; and, then, describes the real-time control tasks, and how they interact with each other, and how they interact with the operator interface task

  12. Identification of Virulence Factors in Nematode-Trapping Fungi - Insights from Genomics, Transcriptomics and Proteomics

    OpenAIRE

    Andersson, Karl-Magnus

    2013-01-01

    Nematode-trapping fungi are soil-living organisms with the unique ability to capture and infect free-living nematodes. The interest in studying these fungi arises from their potential use as biological control agents for plant- and animal-parasitic nematodes. To enter the parasitic stage, nematode-trapping fungi develop different kinds of trapping structures. In order to understand more about the evolution of parasitism in the nematode-trapping fungi and to identify virulence factors in these...

  13. Crystal Structure of [Bis(DIMETHYLFORMAMIDE Bis (2,2’-PYRIDYLQUINOLINE Iron (II] Bis-(TETRAPHENYLBORATE

    Directory of Open Access Journals (Sweden)

    Bohari M. Yamin

    2009-11-01

    Full Text Available The goal of this research is to obtain single crystal and structural information of iron(II complex with 2,(2'-pyridylquinoline(pq ligands. The reaction of iron(II salt with 2,(2'-pyridylquinoline ligand and sodiumtetraphenylborate in the molar ratio of 1:3:2 in methanol-N,N-dimethylformamide(dmf solution results in an iron(IIcomplex. The formula of the [Fe(pq2(dmf2](BPh42 complex has been obtained from the iron(II and C, H, N contents.Single crystal of [Fe(pq2(dmf2](BPh42 suitable for X-ray investigation was obtained by evaporation of the complexsolution in N,N-dimethylformamide at room temperature after 24 hours. This compound crystallizes in monoclinicsystem with C2/c space group, a = 27.950(4, b = 14.169(7, c = 17.717(9 Å and b = 105.669(11°. The structureconsist of iron(II is chelated by two pq ligands through the N atoms and two dmf molecules in a six-coordinationenvironment. The charge of the [Fe(pq2(dmf2]2+ cation is balanced by two tetraphenylborate (BPh4- anions.

  14. ATRAP - Progress Towards Trapped Antihydrogen

    International Nuclear Information System (INIS)

    Grzonka, D.; Goldenbaum, F.; Oelert, W.; Sefzick, T.; Zhang, Z.; Comeau, D.; Hessels, E.A.; Storry, C.H.; Gabrielse, G.; Larochelle, P.; Lesage, D.; Levitt, B.; Speck, A.; Haensch, T.W.; Pittner, H.; Walz, J.

    2005-01-01

    The ATRAP experiment at the CERN antiproton decelerator AD aims for a test of the CPT invariance by a high precision comparison of the 1s-2s transition in the hydrogen and the antihydrogen atom.Antihydrogen production is routinely operated at ATRAP and detailed studies have been performed in order to optimize the production efficiency of useful antihydrogen.For high precision measurements of atomic transitions cold antihydrogen in the ground state is required which must be trapped due to the low number of available antihydrogen atoms compared to the cold hydrogen beam used for hydrogen spectroscopy. To ensure a reasonable antihydrogen trapping efficiency a magnetic trap has to be superposed the nested Penning trap. First trapping tests of charged particles within a combined magnetic/Penning trap have started at ATRAP

  15. ATRAP Progress Towards Trapped Antihydrogen

    CERN Document Server

    Grzonka, D; Gabrielse, G; Goldenbaum, F; Hänsch, T W; Hessels, E A; Larochelle, P; Le Sage, D; Levitt, B; Oelert, W; Pittner, H; Sefzick, T; Speck, A; Storry, C H; Walz, J; Zhang, Z

    2005-01-01

    The ATRAP experiment at the CERN antiproton decelerator AD aims for a test of the CPT invariance by a high precision comparison of the 1s‐2s transition in the hydrogen and the antihydrogen atom. Antihydrogen production is routinely operated at ATRAP and detailed studies have been performed in order to optimize the production efficiency of useful antihydrogen. For high precision measurements of atomic transitions cold antihydrogen in the ground state is required which must be trapped due to the low number of available antihydrogen atoms compared to the cold hydrogen beam used for hydrogen spectroscopy. To ensure a reasonable antihydrogen trapping efficiency a magnetic trap has to be superposed the nested Penning trap. First trapping tests of charged particles within a combined magnetic/Penning trap have started at ATRAP.

  16. Three-dimensional electromagnetic strong turbulence. II. Wave packet collapse and structure of wave packets during strong turbulence

    International Nuclear Information System (INIS)

    Graham, D. B.; Robinson, P. A.; Cairns, Iver H.; Skjaeraasen, O.

    2011-01-01

    Large-scale simulations of wave packet collapse are performed by numerically solving the three-dimensional (3D) electromagnetic Zakharov equations, focusing on individual wave packet collapses and on wave packets that form in continuously driven strong turbulence. The collapse threshold is shown to decrease as the electron thermal speed ν e /c increases and as the temperature ratio T i /T e of ions to electrons decreases. Energy lost during wave packet collapse and dissipation is shown to depend on ν e /c. The dynamics of density perturbations after collapse are studied in 3D electromagnetic strong turbulence for a range of T i /T e . The structures of the Langmuir, transverse, and total electric field components of wave packets during strong turbulence are investigated over a range of ν e /c. For ν e /c e /c > or approx. 0.17, transverse modes become trapped in density wells and contribute significantly to the structure of the total electric field. At all ν e /c, the Langmuir energy density contours of wave packets are predominantly oblate (pancake shaped). The transverse energy density contours of wave packets are predominantly prolate (sausage shaped), with the major axis being perpendicular to the major axes of the Langmuir component. This results in the wave packet becoming more nearly spherical as ν e /c increases, and in turn generates more spherical density wells during collapse. The results obtained are compared with previous 3D electrostatic results and 2D electromagnetic results.

  17. Reinforced soil structures. Volume II, Summary of research and systems information

    Science.gov (United States)

    1989-11-01

    Volume II was essentially prepared as an Appendix of supporting information for Volume I. This volume contains much of the supporting theory and a summary of the research used to verify the design approach contained in Volume I, as well as general in...

  18. Synthesis, crystal structure and DFT calculations of a new Hg (II) metal-organic polymer

    Czech Academy of Sciences Publication Activity Database

    Mirtamizdoust, B.; Roodsari, M.S.; Shaabani, B.; Dušek, Michal; Fejfarová, Karla

    2016-01-01

    Roč. 15, č. 3 (2016), s. 257-266 ISSN 1024-1221 Grant - others:AV ČR(CZ) Praemium Academiae Institutional support: RVO:68378271 Keywords : mercury (II) iodide * coordination polymer * square planar * tetrahedral geometry * density functional calculation Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.565, year: 2016

  19. Calibration of optically trapped nanotools

    Energy Technology Data Exchange (ETDEWEB)

    Carberry, D M; Simpson, S H; Grieve, J A; Hanna, S; Miles, M J [H H Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); Wang, Y; Schaefer, H; Steinhart, M [Institute for Chemistry, University of Osnabrueck, Osnabrueck (Germany); Bowman, R; Gibson, G M; Padgett, M J, E-mail: m.j.miles@bristol.ac.uk [SUPA, Department of Physics and Astronomy, University of Glasgow, Science Road, Glasgow G12 8QQ (United Kingdom)

    2010-04-30

    Holographically trapped nanotools can be used in a novel form of force microscopy. By measuring the displacement of the tool in the optical traps, the contact force experienced by the probe can be inferred. In the following paper we experimentally demonstrate the calibration of such a device and show that its behaviour is independent of small changes in the relative position of the optical traps. Furthermore, we explore more general aspects of the thermal motion of the tool.

  20. Tracing of border trap behavior by noise analysis in microelectronics

    International Nuclear Information System (INIS)

    Sharshar, K.A.A.; Shaalan, A.A.M.; Gomaa, E.I.

    2008-01-01

    The present state of art of this work is to study the electrical defects of the silicon- silicon dioxide interface created by gamma rays (Co 60 ) in submicron MOS devices used in telecommunication systems. We focus our investigation on a particular class of trapped charge located near the interface characterized as the border traps. The expected physical location and chemical structure of the traps were discussed. The low frequency 1/f noise measurement is used in the estimation of border trap densities before and after irradiation; the results are reported for n-MOS transistor exposed to doses (0.3, 0.5, 1 and 10 Mrad). The border trap population in the irradiated samples increased from 7.6*10 10 up to 1.03*10 11 eV -1 Cm -2

  1. Structural and Molecular Properties of Insect Type II Motor Axon Terminals

    Directory of Open Access Journals (Sweden)

    Bettina Stocker

    2018-03-01

    Full Text Available A comparison between the axon terminals of octopaminergic efferent dorsal or ventral unpaired median neurons in either desert locusts (Schistocerca gregaria or fruit flies (Drosophila melanogaster across skeletal muscles reveals many similarities. In both species the octopaminergic axon forms beaded fibers where the boutons or varicosities form type II terminals in contrast to the neuromuscular junction (NMJ or type I terminals. These type II terminals are immunopositive for both tyramine and octopamine and, in contrast to the type I terminals, which possess clear synaptic vesicles, only contain dense core vesicles. These dense core vesicles contain octopamine as shown by immunogold methods. With respect to the cytomatrix and active zone peptides the type II terminals exhibit active zone-like accumulations of the scaffold protein Bruchpilot (BRP only sparsely in contrast to the many accumulations of BRP identifying active zones of NMJ type I terminals. In the fruit fly larva marked dynamic changes of octopaminergic fibers have been reported after short starvation which not only affects the formation of new branches (“synaptopods” but also affects the type I terminals or NMJs via octopamine-signaling (Koon et al., 2011. Our starvation experiments of Drosophila-larvae revealed a time-dependency of the formation of additional branches. Whereas after 2 h of starvation we find a decrease in “synaptopods”, the increase is significant after 6 h of starvation. In addition, we provide evidence that the release of octopamine from dendritic and/or axonal type II terminals uses a similar synaptic machinery to glutamate release from type I terminals of excitatory motor neurons. Indeed, blocking this canonical synaptic release machinery via RNAi induced downregulation of BRP in neurons with type II terminals leads to flight performance deficits similar to those observed for octopamine mutants or flies lacking this class of neurons (Brembs et al., 2007.

  2. Synthesis, crystal structure and electrochemical and DNA binding studies of oxygen bridged-copper(II) carboxylate

    Science.gov (United States)

    Iqbal, Muhammad; Ali, Saqib; Tahir, Muhammad Nawaz; Muhammad, Niaz; Shah, Naseer Ali; Sohail, Manzar; Pandarinathan, Vedapriya

    2015-08-01

    A new binuclear O-bridged Cu(II) complex with 4-chlorophenyl acetate and 2,2‧-bipyridine has been synthesized and characterized using FT-IR, powder and single crystal XRD and electrochemical solution studies. The results revealed that the two penta-coordinated Cu(II) centers are linked by two carboxylate ligands in end-on bonding fashion. The coordination geometry is slightly distorted square pyramidal (SP) with bridging oxygen atoms occupying the apical position and other ligands lying in the equatorial plane. The striking difference in Cu-O bond distance of the bridging oxygen atom in the complex may be responsible for the SP geometry of Cu(II) ion. The complex gave rise to metal centered irreversible electro-activity where one electron Cu(II)/Cu(III) oxidation process and a single step two electron Cu(II)/Cu(0) reduction process was observed. The redox processes were found predominantly adsorption controlled. The values of diffusion coefficient and heterogeneous rate constant for oxidation process were 6.98 × 10-7 cm2 s-1 and 4.60 × 10-5 cm s-1 while the corresponding values for reduction were 5.30 × 10-8 cm2 s-1 and 5.41 × 10-6 cm s-1, respectively. The formal potential and charge transfer coefficient were also calculated. The DNA-binding ability was explored through cyclic voltammetry and UV-Visible spectroscopy. Diminution in the value of Do for oxidation indicated the binding of the complex with DNA corresponding to Kb = 8.58 × 104 M-1. UV-Visible spectroscopy yielded ε = 49 L mol-1 cm-1 and Kb = 2.96 × 104 M-1. The data of both techniques support each other. The self-induced redox activation of the complex, as indicated by cyclic voltammetry heralds its potential applications in redox catalysis and anticancer activity.

  3. Catecholase activity of dicopper(II)-bispidine complexes: stabilities and structures of intermediates, kinetics and reaction mechanism.

    Science.gov (United States)

    Born, Karin; Comba, Peter; Daubinet, André; Fuchs, Alexander; Wadepohl, Hubert

    2007-01-01

    A mechanism for the oxidation of 3,5-di-tert-butylcatechol (dtbc) with dioxygen to the corresponding quinone (dtbq), catalyzed by bispidine-dicopper complexes (bispidines are various mono- and dinucleating derivatives of 3,7-diazabicyclo[3.3.1]nonane with bis-tertiary-amine-bispyridyl or bis-tertiary-amine-trispyridyl donor sets), is proposed on the basis of (1) the stoichiometry of the reaction as well as the stabilities and structures [X-ray, density functional theory (B3LYP, TZV)] of the bispidine-dicopper(II)-3,4,5,6-tetrachlorcatechol intermediates, (2) formation kinetics and structures (molecular mechanics, MOMEC) of the end-on peroxo-dicopper(II) complexes and (3) kinetics of the stoichiometric (anaerobic) and catalytic (aerobic) copper-complex-assisted oxidation of dtbc. This involves (1) the oxidation of the dicopper(I) complexes with dioxygen to the corresponding end-on peroxo-dicopper(II) complexes, (2) coordination of dtbc as a bridging ligand upon liberation of H(2)O(2) and (3) intramolecular electron transfer to produce dtbq, which is liberated, and the dicopper(I) catalyst. Although the bispidine complexes have reactivities comparable to those of recently published catalysts with macrocyclic ligands, which seem to reproduce the enzyme-catalyzed process in various reaction sequences, a strikingly different oxidation mechanism is derived from the bispidine-dicopper-catalyzed reaction.

  4. Optical traps with geometric aberrations

    International Nuclear Information System (INIS)

    Roichman, Yael; Waldron, Alex; Gardel, Emily; Grier, David G.

    2006-01-01

    We assess the influence of geometric aberrations on the in-plane performance of optical traps by studying the dynamics of trapped colloidal spheres in deliberately distorted holographic optical tweezers. The lateral stiffness of the traps turns out to be insensitive to moderate amounts of coma, astigmatism, and spherical aberration. Moreover holographic aberration correction enables us to compensate inherent shortcomings in the optical train, thereby adaptively improving its performance. We also demonstrate the effects of geometric aberrations on the intensity profiles of optical vortices, whose readily measured deformations suggest a method for rapidly estimating and correcting geometric aberrations in holographic trapping systems

  5. Investigating the Theoretical Structure of the DAS-II Core Battery at School Age Using Bayesian Structural Equation Modeling

    Science.gov (United States)

    Dombrowski, Stefan C.; Golay, Philippe; McGill, Ryan J.; Canivez, Gary L.

    2018-01-01

    Bayesian structural equation modeling (BSEM) was used to investigate the latent structure of the Differential Ability Scales-Second Edition core battery using the standardization sample normative data for ages 7-17. Results revealed plausibility of a three-factor model, consistent with publisher theory, expressed as either a higher-order (HO) or a…

  6. Some neutronic studies on flux-trap type moderator

    International Nuclear Information System (INIS)

    Kiyanagi, Y.; Watanabe, N.

    1991-01-01

    The neutronic performance of a flux-trap type moderator was studied by computer simulation in connection with the KENS-II target-moderator system. It was confirmed that this system can provide 1.3-1.4 times higher neutron intensity than a traditional wing-geometry moderator system. (author)

  7. Practical aspects of trapped ion mass spectrometry, 5 applications of ion trapping devices

    CERN Document Server

    March, Raymond E

    2009-01-01

    Examines ion/neutral and ion/ion reactions, ion spectroscopy, and the structural characterization of proteins and peptides using quadropole ion trap mass spectrometry, Fourier transform - ion cyclotron resonance (FT-ICR) mass spectrometry, and traveling wave ion mobility mass spectrometry.

  8. Structural zinc(II thiolate complexes relevant to the modeling of Ada repair protein: Application toward alkylation reactions

    Directory of Open Access Journals (Sweden)

    Mohamed M. Ibrahim

    2014-11-01

    Full Text Available The TtZn(II-bound perchlorate complex [TtZn–OClO3] 1 (Ttxyly = hydrotris[N-xylyl-thioimidazolyl]borate was used for the synthesis of zinc(II-bound ethanthiothiol complex [TtZn–SCH2CH3] 2 and its hydrogen-bond containing analog Tt–ZnSCH2CH2–NH(COOC(CH33 3. These thiolate complexes were examined as structural models for the active sites of Ada repair protein toward methylation reactions. The Zn[S3O] coordination sphere in complex 1 includes three thione donors from the ligand Ttixyl and one oxygen donor from the perchlorate coligand in ideally tetrahedral arrangement around the zinc center. The average Zn(1–S(thione bond length is 2.344 Å, and the Zn(1–O(1 bond length is 1.917 Å.

  9. Structural analysis and differentiation of reducing and nonreducing neutral model starch oligosaccharides by negative-ion electrospray ionization ion-trap mass spectrometry

    Czech Academy of Sciences Publication Activity Database

    Čmelík, Richard; Chmelík, Josef

    2010-01-01

    Roč. 291, 1-2 (2010), s. 33-40 ISSN 1387-3806 R&D Projects: GA MŠk 2B06037 Institutional research plan: CEZ:AV0Z40310501 Keywords : structural analysis * oligosaccharides * electrospray mass spectrometry Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 2.009, year: 2010

  10. A live-trap and trapping technique for fossorial mammals

    African Journals Online (AJOL)

    mammals. G.C. Hickman. An effective live-trap was designed for Cryptomys hottentotus .... that there is an animal in the burrow system, and to lessen the likelihood of the .... the further testing and modification of existing trap types. Not only is it ...

  11. Electron traps in semiconducting polymers : Exponential versus Gaussian trap distribution

    NARCIS (Netherlands)

    Nicolai, H. T.; Mandoc, M. M.; Blom, P. W. M.

    2011-01-01

    The low electron currents in poly(dialkoxy-p-phenylene vinylene) (PPV) derivatives and their steep voltage dependence are generally explained by trap-limited conduction in the presence of an exponential trap distribution. Here we demonstrate that the electron transport of several PPV derivatives can

  12. Electron traps in semiconducting polymers: exponential versus Gaussian trap distribution

    NARCIS (Netherlands)

    Nicolai, H.T.; Mandoc, M.M.; Blom, P.W.M.

    2011-01-01

    The low electron currents in poly(dialkoxy-p-phenylene vinylene) (PPV) derivatives and their steep voltage dependence are generally explained by trap-limited conduction in the presence of an exponential trap distribution. Here we demonstrate that the electron transport of several PPV derivatives can

  13. Crystal structures of bis- and hexakis[(6,6′-dihydroxybipyridinecopper(II] nitrate coordination complexes

    Directory of Open Access Journals (Sweden)

    Deidra L. Gerlach

    2015-12-01

    Full Text Available Two multinuclear complexes synthesized from Cu(NO32 and 6,6′-dihydroxybipyridine (dhbp exhibit bridging nitrate and hydroxide ligands. The dinuclear complex (6,6′-dihydroxybipyridine-2κ2N,N′[μ-6-(6-hydroxypyridin-2-ylpyridin-2-olato-1:2κ3N,N′:O2](μ-hydroxido-1:2κ2O:O′(μ-nitrato-1:2κ2O:O′(nitrato-1κOdicopper(II, [Cu2(C10H7N2O2(OH(NO32(C10H8N2O2] or [Cu(6-OH-6′-O-bpy(NO3(μ-OH(μ-NO3Cu(6,6′-dhbp], (I, with a 2:1 ratio of nitrate to hydroxide anions and one partially deprotonated dhbp ligand, forms from a water–ethanol mixture at neutral pH. The hexanuclear complex bis(μ3-bipyridine-2,2′-diolato-κ3O:N,N′:O′tetrakis(6,6′-dihydroxybipyridine-κ2N,N′tetrakis(μ-hydroxido-κ2O:O′bis(methanol-κOtetrakis(μ-nitrato-κ2O:O′hexacopper(II, [Cu6(C10H6N2O22(CH4O2(OH4(NO34(C10H8N2O24] or [Cu(6,6′-dhbp(μ-NO32(μ-OHCu(6,6′-O-bpy(μ-OHCu(6,6′dhbp(CH3OH]2, (II, with a 1:1 NO3–OH ratio and two fully protonated and fully deprotonated dhbp ligands, was obtained by methanol recrystallization of material obtained at pH 3. Complex (II lies across an inversion center. Complexes (I and (II both display intramolecular O—H...O hydrogen bonding. Intermolecular O—H...O hydrogen bonding links symmetry-related molecules forming chains along [100] for complex (I with π-stacking along [010] and [001]. Complex (II forms intermolecular O—H...O hydrogen-bonded chains along [010] with π-stacking along [100] and [001].

  14. CCDC 1515632: Experimental Crystal Structure Determination : hexakis(dimethyl sulfoxide)-manganese(ii) tetraiodide

    KAUST Repository

    Haque, M.A.; Davaasuren, Bambar; Rothenberger, Alexander; Wu, Tao

    2016-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from

  15. Data Analysis Algorithm Suitable for Structural Health Monitoring Based on Dust Network, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposed project will attempt to develop a data analysis system for structural health monitoring on space structures. The data analysis software will be a key...

  16. TRAP230/ARC240 and TRAP240/ARC250 Mediator subunits are functionally conserved through evolution

    DEFF Research Database (Denmark)

    Samuelsen, Camilla O; Baraznenok, Vera; Khorosjutina, Olga

    2003-01-01

    In Saccharomyces cerevisiae Mediator, a subgroup of proteins (Srb8, Srb9, Srb10, and Srb11) form a module, which is involved in negative regulation of transcription. Homologues of Srb10 and Srb11 are found in some mammalian Mediator preparations, whereas no clear homologues have been reported...... for Srb8 and Srb9. Here, we identify a TRAP240/ARC250 homologue in Schizosaccharomyces pombe and demonstrate that this protein, spTrap240, is stably associated with a larger form of Mediator, which also contains conserved homologues of Srb8, Srb10, and Srb11. We find that spTrap240 and Sch. pombe Srb8 (sp......Srb8) regulate the same distinct subset of genes and have indistinguishable phenotypic characteristics. Importantly, Mediator containing the spSrb8/spTrap240/spSrb10/spSrb11 subunits is isolated only in free form, devoid of RNA polymerase II. In contrast, Mediator lacking this module associates...

  17. Short-interval test-retest interrater reliability of the Dutch version of the structured clinical interview for DSM-IV personality disorders (SCID-II)

    NARCIS (Netherlands)

    Weertman, A; ArntZ, A; Dreessen, L; van Velzen, C; Vertommen, S

    2003-01-01

    This study examined the short-interval test-retest reliability of the Structured Clinical Interview (SCID-II: First, Spitzer, Gibbon, & Williams, 1995) for DSM-IV personality disorders (PDs). The SCID-II was administered to 69 in- and outpatients on two occasions separated by 1 to 6 weeks. The

  18. Segmented trapped vortex cavity

    Science.gov (United States)

    Grammel, Jr., Leonard Paul (Inventor); Pennekamp, David Lance (Inventor); Winslow, Jr., Ralph Henry (Inventor)

    2010-01-01

    An annular trapped vortex cavity assembly segment comprising includes a cavity forward wall, a cavity aft wall, and a cavity radially outer wall there between defining a cavity segment therein. A cavity opening extends between the forward and aft walls at a radially inner end of the assembly segment. Radially spaced apart pluralities of air injection first and second holes extend through the forward and aft walls respectively. The segment may include first and second expansion joint features at distal first and second ends respectively of the segment. The segment may include a forward subcomponent including the cavity forward wall attached to an aft subcomponent including the cavity aft wall. The forward and aft subcomponents include forward and aft portions of the cavity radially outer wall respectively. A ring of the segments may be circumferentially disposed about an axis to form an annular segmented vortex cavity assembly.

  19. Detection of trapped antihydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Hydomako, Richard [Calgary Univ., AB (Canada). Dept. of Physics and Astronomy

    2013-02-01

    A landmark thesis describing the first ever trapping of antihydrogen atoms in CERN's ALPHA apparatus. Opens the way to crucial tests of fundamental theories. Nominated as an outstanding contribution by the University of Calgary. In 2010, the ALPHA collaboration achieved a first for mankind: the stable, long-term storage of atomic antimatter, a project carried out a the Antiproton Decelerator facility at CERN. A crucial element of this observation was a dedicated silicon vertexing detector used to identify and analyze antihydrogen annihilations. This thesis reports the methods used to reconstruct the annihilation location. Specifically, the methods used to identify and extrapolate charged particle tracks and estimate the originating annihilation location are outlined. Finally, the experimental results demonstrating the first-ever magnetic confinement of antihydrogen atoms are presented. These results rely heavily on the silicon detector, and as such, the role of the annihilation vertex reconstruction is emphasized.

  20. Atmospheric structure deduced from disturbed line profiles application to Ca II lines

    International Nuclear Information System (INIS)

    Mein, N.; Mein, P.; Malherbe, J.-M.; Dame, L.; Dumont, S.; CNRS, Laboratoire de Physique Stellaire et Planetaire, Verrieres-le-Buisson, France; College de France, Paris)

    1985-01-01

    A new method is described in order to derive physical quantities (temperature, pressure, radial velocities) from the observation of disturbed line profiles. A method of Fourier analysis is suggested with double profiles and a nonlinear expansion of the coefficient of the Fourier terms. An application to a sequence of H-Ca II lines is attempted. The method is a powerful tool allowing for the simultaneous determination of at least four physical quantities. 9 references

  1. Backbone assignment and secondary structure of the PsbQ protein from Photosystem II

    Czech Academy of Sciences Publication Activity Database

    Horničáková, M.; Kohoutová, Jaroslava; Schlagnitweit, J.; Wohlschlager, Ch.; Ettrich, Rüdiger; Fiala, R.; Schoefberger, W.; Müller, N.

    2011-01-01

    Roč. 5, č. 2 (2011), s. 169-175 ISSN 1874-2718 R&D Projects: GA MŠk(CZ) LC06010 Institutional research plan: CEZ:AV0Z60870520 Keywords : Photosystem II * PsbQ * Missing link * NMR resonance assignment * Protein-protein interaction Subject RIV: BO - Biophysics Impact factor: 0.720, year: 2011 http://www.springerlink.com/content/3n38075w5h1l1082/fulltext.pdf

  2. Comparison of Solar Fine Structure Observed Simultaneously in Lyα and Mg II h

    Science.gov (United States)

    Schmit, D.; Sukhorukov, A. V.; De Pontieu, B.; Leenaarts, J.; Bethge, C.; Winebarger, A.; Auchère, F.; Bando, T.; Ishikawa, R.; Kano, R.; Kobayashi, K.; Narukage, N.; Trujillo Bueno, J.

    2017-10-01

    The Chromospheric Lyman Alpha Spectropolarimeter (CLASP) observed the Sun in H I Lyα during a suborbital rocket flight on 2015 September 3. The Interface Region Imaging Telescope (IRIS) coordinated with the CLASP observations and recorded nearly simultaneous and co-spatial observations in the Mg II h and k lines. The Mg II h and Lyα lines are important transitions, energetically and diagnostically, in the chromosphere. The canonical solar atmosphere model predicts that these lines form in close proximity to each other and so we expect that the line profiles will exhibit similar variability. In this analysis, we present these coordinated observations and discuss how the two profiles compare over a region of quiet Sun at viewing angles that approach the limb. In addition to the observations, we synthesize both line profiles using a 3D radiation-MHD simulation. In the observations, we find that the peak width and the peak intensities are well correlated between the lines. For the simulation, we do not find the same relationship. We have attempted to mitigate the instrumental differences between IRIS and CLASP and to reproduce the instrumental factors in the synthetic profiles. The model indicates that formation heights of the lines differ in a somewhat regular fashion related to magnetic geometry. This variation explains to some degree the lack of correlation, observed and synthesized, between Mg II and Lyα. Our analysis will aid in the definition of future observatories that aim to link dynamics in the chromosphere and transition region.

  3. Comparison of Solar Fine Structure Observed Simultaneously in Ly α and Mg ii h

    Energy Technology Data Exchange (ETDEWEB)

    Schmit, D. [Bay Area Environmental Research Institute, 625 2nd Street, Suite 209, Petaluma, CA 94952 (United States); Sukhorukov, A. V.; Leenaarts, J. [Institute for Theoretical Astrophysics, University of Oslo, P.O. Box 1029, Blindern NO-0315 Oslo (Norway); De Pontieu, B. [Lockheed Martin Solar and Astrophysics Laboratory, Building 252, 3176 Porter Drive, Palo Alto, CA 94304 (United States); Bethge, C.; Winebarger, A.; Kobayashi, K. [NASA Marshall Space Flight Center, ZP 13, Huntsville, AL 35812 (United States); Auchère, F. [Institut d’Astrophysique Spatiale, CNRS/Univ. Paris-Sud 11, Bâtiment 121, F-91405 Orsay (France); Bando, T.; Kano, R.; Narukage, N. [National Astronomical Observatory of Japan, National Institutes of Natural Sciences, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Ishikawa, R. [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan); Bueno, J. Trujillo [Instituto de Astrofísica de Canarias, E-38205 La Laguna, Tenerife (Spain)

    2017-10-01

    The Chromospheric Lyman Alpha Spectropolarimeter (CLASP) observed the Sun in H i Ly α during a suborbital rocket flight on 2015 September 3. The Interface Region Imaging Telescope ( IRIS ) coordinated with the CLASP observations and recorded nearly simultaneous and co-spatial observations in the Mg ii h and k lines. The Mg ii h and Ly α lines are important transitions, energetically and diagnostically, in the chromosphere. The canonical solar atmosphere model predicts that these lines form in close proximity to each other and so we expect that the line profiles will exhibit similar variability. In this analysis, we present these coordinated observations and discuss how the two profiles compare over a region of quiet Sun at viewing angles that approach the limb. In addition to the observations, we synthesize both line profiles using a 3D radiation-MHD simulation. In the observations, we find that the peak width and the peak intensities are well correlated between the lines. For the simulation, we do not find the same relationship. We have attempted to mitigate the instrumental differences between IRIS and CLASP and to reproduce the instrumental factors in the synthetic profiles. The model indicates that formation heights of the lines differ in a somewhat regular fashion related to magnetic geometry. This variation explains to some degree the lack of correlation, observed and synthesized, between Mg ii and Ly α . Our analysis will aid in the definition of future observatories that aim to link dynamics in the chromosphere and transition region.

  4. Structure-antiproliferative activity studies on l-proline- and homoproline-4-N-pyrrolidine-3-thiosemicarbazone hybrids and their nickel(ii), palladium(ii) and copper(ii) complexes.

    Science.gov (United States)

    Dobrova, Aliona; Platzer, Sonja; Bacher, Felix; Milunovic, Miljan N M; Dobrov, Anatolie; Spengler, Gabriella; Enyedy, Éva A; Novitchi, Ghenadie; Arion, Vladimir B

    2016-09-14

    Two water-soluble thiosemicarbazone-proline (H2L(1)) and thiosemicarbazone-homoproline hybrids (H2L(2)) were synthesised. By reaction of H2L(1) with NiCl2·6H2O, PdCl2 and CuCl2·2H2O in ethanol, the series of square-planar complexes [Ni(H2L(1))Cl]Cl·1.3H2O (1·1.3H2O), [Pd(H2L(1))Cl]Cl·H2O (2·H2O) and [Cu(H2L(1))Cl]Cl·0.7H2O (3·0.7H2O) was prepared, and starting from H2L(2) and CuCl2·2H2O in methanol, the complex [Cu(H2L(2))Cl2]·H2O (4·H2O) was obtained. The compounds have been characterised by elemental analysis, spectroscopic methods (IR, UV-vis and NMR spectroscopy), ESI mass spectrometry and single crystal X-ray crystallography (H2L(1), 1, 2 and 4). As a solid, 1 is diamagnetic, while it is paramagnetic in methanolic solution. The effective magnetic moment of 3.26 B.M. at room temperature indicates the change in coordination geometry from square-planar to octahedral upon dissolution. The in vitro anticancer potency of ligand precursors H2L(1) and H2L(2) and metal complexes 1-4 was studied in three human cancer cell lines (A549, CH1 and SW480) and in noncancerous murine embryonal fibroblasts (NIH/3T3), and the mechanism of cell death was also assayed by flow cytometry. Clear-cut structure-activity relationships have been established. The metal ions exert marked effects in a divergent manner: copper(ii) increases, whereas nickel(ii) and palladium(ii) decrease the cytotoxicity of the hybrids. The antiproliferative activity of H2L(1) and metal complexes 1-3 decreases in all three tumour cell lines in the following rank order: 3 > H2L(1) > 1 > 2. The role of square-planar geometry in the underlying mechanism of cytotoxicity of the metal complexes studied seems to be negligible, while structural modifications at the terminal amino group of thiosemicarbazide and proline moieties are significant for enhancing the antiproliferative activity of both hybrids and copper(ii) complexes.

  5. Four thiophene-pyridyl-amide-based Zn{sup II}/Cd{sup II} coordination polymers: Assembly, structures, photocatalytic properties and fluorescent recognition for Fe{sup 3+}

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiu-Li; Wu, Xiao-Mei; Liu, Guo-Cheng; Li, Qiao-Min; Lin, Hong-Yan; Wang, Xiang

    2017-05-15

    By tuning metal ions and combining with different dicarboxylates, four new semi-rigid thiophene-bis-pyridyl-bis-amide-based coordination polymers, namely, [Zn(3-bptpa)(1,3-BDC)]·DMA·2H{sub 2}O (1), [Zn(3-bptpa)(5-MIP)] (2), [Cd(3-bptpa)(1,3-BDC)]·2H{sub 2}O (3) and [Cd(3-bptpa)(5-MIP)]·4H{sub 2}O (4) (3-bptpa=N,N′-bis(pyridine-3-yl)thiophene-2,5-dicarboxamide, 1,3-H{sub 2}BDC=1,3-benzenedicarboxylic acid, 5-H{sub 2}MIP=5-methylisophthalic acid, DMA=N,N-dimethylacetamide), were solvothermally/hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction analyses, IR spectra, UV–vis diffuse-reflectance spectra (DRS), powder X-ray diffraction (PXRD) and thermal gravimetric analyses (TG). The structural analysis reveals that Zn-complexes 1 and 2 are similar 2D networks. While Cd-complexes 3 and 4 exhibit similar 2-fold interpenetrating 3D α-Po frameworks with the (4{sup 12}·6{sup 3}) topology. The photocatalytic properties for the degradation of methylene blue (MB) under ultraviolet light irradiation of the title complexes have been investigated in detail. Furthermore, the luminescent sensing behaviors for metal cations of 1–4 have been studied, the results indicate that 3 is an excellent fluorescent probe, with high sensitivity, selectivity, and simple regeneration, for environmentally relevant Fe{sup 3+} ions. - Graphical abstract: Four Zn{sup II}/Cd{sup II} coordination polymers with a thiophene-pyridyl-amide ligand have been prepared. The photocatalytic activities and fluorescent sensing properties for metal ions of the title complexes have been investigated. - Highlights: • Four coordination polymers with thiophene-pyridyl-amide ligands have been obtained. • The central metal ions play an important role in the formation of the frameworks. • The photoluminescent sensing and the photocatalytic properties have been investigated.

  6. Light effect in photoionization of traps in GaN MESFETs

    Directory of Open Access Journals (Sweden)

    H. Arabshahi

    2009-09-01

    Full Text Available Trapping of hot electron behavior by trap centers located in buffer layer of a wurtzite phase GaN MESFET has been simulated using an ensemble Monte Carlo simulation. The results of the simulation show that the trap centers are responsible for current collapse in GaN MESFET at low temperatures. These electrical traps degrade the performance of the device at low temperature. On the opposite, a light-induced increase in the trap-limited drain current, results from the photoionization of trapped carriers and their return to the channel under the influence of the built in electric field associated with the trapped charge distribution. The simulated device geometries and doping are matched to the nominal parameters described for the experimental structures as closely as possible, and the predicted drain current and other electrical characteristics for the simulated device including trapping center effects show close agreement with the available experimental data.

  7. Crystal Structures and Characterizations of Bis(1-benzoyl methyl-benzotriazole-N3)dichoro Metal(II) Complex:[MCl2-(C6H4N3CH2COPh)2] [M=Zn(II), Co(II)

    Institute of Scientific and Technical Information of China (English)

    JIAN,Fang-Fang(建方方); SUN,Ping-Ping(孙萍萍); XIAO,Hai-Lian(肖海连); JIAO,Kui(焦奎)

    2004-01-01

    The structures of [MCl2(C6H4N3CH2COPh)2] [M=Zn(II) (1), Co(II) (2)] have been determined by X-ray crystallography. They were characterized by elemental analysis, IR spectrum, electronic spectrum and thermogravimetric-differential thermal analysis. They all crystallize in the triclinic system, space group Pī, with lattice parameters a=0.9449(2) nm, b=1.1291(2) nm, c=1.3637(3) nm, α=111.70(3)°, β=94.33(3)°, γ=90.97(3), Z=2 for compound 1; a=0.9437(2) nm, b=1.1277(2) nm, c=1.3650(3) nm, α=111.76(3)°, β=94.50(3)°, γ=90.80(3)°, Z=2 for compound 2. The metal ions are all coordinated by two Cl- anions and two nitrogen atoms of 1-benzoylmethyl-benzotriazole ligands, forming the distorted tetrahedral geometry. The Zn-Cl and Zn-N bond lengths are 0.2209(2), 0.2210(2) nm and 0.2059(4), 0.2067(4) nm, respectively. The Co-Cl and Co-N bond lengths are 0.2215(2), 0.2222(2) nm and 0.2028(5), 0.2045(5) nm, respectively. The thermogravimetric (TG) data indicate that they are nearly similar in TG curve, and there are not structural transitions in the two compounds. They all have a high thermal stability. But, there is little difference in DTG (differential thermogravimetric) curves of those two compounds. Elemental analysis, electronic and IR spectra are in agreement with the structural data.

  8. Structural information on the coordination compounds formed by manganese(II), cobalt(II), nickel(II), zinc(II), cadmium(II) and mercury(II) thiocyanates with 4-cyanopyridine N-oxide from their magnetic moments, electronic and infrared spectra

    Science.gov (United States)

    Ahuja, I. S.; Yadava, C. L.; Singh, Raghuvir

    1982-05-01

    Coordination compounds formed by the interaction of 4-cyanopyridine. N-oxide (4-CPO), a potentially bidentate ligand, with manganese(II), cobalt(II), nickel(II), zinc(II), cadmium(II) and rnercury(II) thiocyanates have been prepared and characterized from their elemental analyses, magnetic susceptibilities, electronic and infrared spectral studies down to 200 cm -1 in the solid state. The compounds isolated are: Mn(4-CPO) 2(NCS) 2, Co(4-CPO) 2(NCS) 2,Ni(4-CPO) 2(NCS) 2,Zn(4-CPO) 2(NCS) 2, Cd(4-CPO)(NCS) 2 and Hg(4-CPO) 2(SCN) 2. It is shown that 4-CPO acts as a terminal N-oxide oxygen bonded monodentate ligand in all the metal(II) thiocyanate complexes studied. Tentative stereochemistries of the complexes in the solid state are discussed. The ligand field parameters 10 Dq, B, β and λ calculated for the manganese(II), cobalt(II) and nickel(II) complexes are consistent with their proposed stereochemistries.

  9. The range of attraction for light traps catching Culicoides biting midges (Diptera: Ceratopogonidae).

    Science.gov (United States)

    Kirkeby, Carsten; Græsbøll, Kaare; Stockmarr, Anders; Christiansen, Lasse E; Bødker, René

    2013-03-15

    Culicoides are vectors of e.g. bluetongue virus and Schmallenberg virus in northern Europe. Light trapping is an important tool for detecting the presence and quantifying the abundance of vectors in the field. Until now, few studies have investigated the range of attraction of light traps. Here we test a previously described mathematical model (Model I) and two novel models for the attraction of vectors to light traps (Model II and III). In Model I, Culicoides fly to the nearest trap from within a fixed range of attraction. In Model II Culicoides fly towards areas with greater light intensity, and in Model III Culicoides evaluate light sources in the field of view and fly towards the strongest. Model II and III incorporated the directionally dependent light field created around light traps with fluorescent light tubes. All three models were fitted to light trap collections obtained from two novel experimental setups in the field where traps were placed in different configurations. Results showed that overlapping ranges of attraction of neighboring traps extended the shared range of attraction. Model I did not fit data from any of the experimental setups. Model II could only fit data from one of the setups, while Model III fitted data from both experimental setups. The model with the best fit, Model III, indicates that Culicoides continuously evaluate the light source direction and intensity. The maximum range of attraction of a single 4W CDC light trap was estimated to be approximately 15.25 meters. The attraction towards light traps is different from the attraction to host animals and thus light trap catches may not represent the vector species and numbers attracted to hosts.

  10. Zinc(II) halide complexes with 2-methoxyaniline ligand: Synthesis, characterization, thermal analyses, crystal structure determination and luminescent properties

    Science.gov (United States)

    Amani, Vahid

    2018-03-01

    Three new mononuclear zinc(II) complexes, [Zn(2-MeO-C6H4NH2)2X2] (X is Cl in 1, Br in 2 and I in 3), were prepared from the reactions of ZnX2 with 2-methoxyaniline (2-MeO-C6H4NH2) ligand in methanol. Suitable crystals of these complexes were obtained for X-ray diffraction measurements by slow evaporation of methanol solution at room temperature. The three complexes were thoroughly characterized by thermogravimetric analysis, elemental analysis (CHNO), spectral methods (IR, UV-Vis, 13C{1H}NMR, 1H NMR and luminescence), and single crystal X-ray diffraction. The X-ray structural analysis indicated that in the structures of these complexes, the zinc(II) cation is four-coordinated in a distorted tetrahedral configuration by two N atoms from two 2-methoxyanyline ligands and two halide anions. Also, in these complexes intermolecular interactions, for example Nsbnd H⋯X hydrogen bonds (in 1-3), Csbnd H⋯X hydrogen bonds (in 3), Csbnd H⋯π interactions (in 1 and 2) and π⋯π interactions (in 3), are effective in the stabilization of the crystal structures. In addition, the luminescence spectra of all complexes in methanolic solution show that the intensity of their emission bands is stronger than that for free 2-methoxyaniline ligand.

  11. Flux trapping in superconducting cavities

    International Nuclear Information System (INIS)

    Vallet, C.; Bolore, M.; Bonin, B.; Charrier, J.P.; Daillant, B.; Gratadour, J.; Koechlin, F.; Safa, H.

    1992-01-01

    The flux trapped in various field cooled Nb and Pb samples has been measured. For ambient fields smaller than 3 Gauss, 100% of the flux is trapped. The consequences of this result on the behavior of superconducting RF cavities are discussed. (author) 12 refs.; 2 figs

  12. Injection into electron plasma traps

    International Nuclear Information System (INIS)

    Gorgadze, Vladimir; Pasquini, Thomas A.; Fajans, Joel; Wurtele, Jonathan S.

    2003-01-01

    Computational studies and experimental measurements of plasma injection into a Malmberg-Penning trap reveal that the number of trapped particles can be an order of magnitude higher than predicted by a simple estimates based on a ballistic trapping model. Enhanced trapping is associated with a rich nonlinear dynamics generated by the space-charge forces of the evolving trapped electron density. A particle-in-cell simulation is used to identify the physical mechanisms that lead to the increase in trapped electrons. The simulations initially show strong two-stream interactions between the electrons emitted from the cathode and those reflected off the end plug of the trap. This is followed by virtual cathode oscillations near the injection region. As electrons are trapped, the initially hollow longitudinal phase-space is filled, and the transverse radial density profile evolves so that the plasma potential matches that of the cathode. Simple theoretical arguments are given that describe the different dynamical regimes. Good agreement is found between simulation and theory

  13. Electromagnetic trapping of neutral atoms

    International Nuclear Information System (INIS)

    Metcalf, H.J.

    1986-01-01

    Cooling and trapping of neutral atoms is a new branch of applied physics that has potential for application in many areas. The authors present an introduction to laser cooling and magnetic trapping. Some basic ideas and fundamental limitations are discussed, and the first successful experiments are reviewed. Trapping a neutral object depends on the interaction between an inhomogeneous electromagnetic field and a multiple moment that results in the exchange of kinetic for potential energy. In neutral atom traps, the potential energy must be stored as internal atomic energy, resulting in two immediate and extremely important consequences. First, the atomic energy levels will necessarily shift as the atoms move in the trap, and, second, practical traps for ground state neutral atoms atr necessarily very shallow compared to thermal energy. This small depth also dictates stringent vacuum requirements because a trapped atom cannot survive a single collision with a thermal energy background gas molecule. Neutral trapping, therefore, depends on substantial cooling of a thermal atomic sample and is inextricably connected with the cooling process

  14. Quantum computing with trapped ions

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, R.J.

    1998-01-01

    The significance of quantum computation for cryptography is discussed. Following a brief survey of the requirements for quantum computational hardware, an overview of the ion trap quantum computation project at Los Alamos is presented. The physical limitations to quantum computation with trapped ions are analyzed and an assessment of the computational potential of the technology is made.

  15. Trapped surfaces in spherical stars

    International Nuclear Information System (INIS)

    Bizon, P.; Malec, E.; O'Murchadha, N.

    1988-01-01

    We give necessary and sufficient conditions for the existence of trapped surfaces in spherically symmetric spacetimes. These conditions show that the formation of trapped surfaces depends on both the degree of concentration and the average flow of the matter. The result can be considered as a partial validation of the cosmic-censorship hypothesis

  16. Structural, spectral and magnetic studies of two Co(II)-N-heterocyclic diphosphonates based on multinuclear units

    Science.gov (United States)

    Zhao, Chen; Ma, Kui-Rong; Zhang, Yu; Kan, Yu-He; Li, Rong-Qing; Hu, Hua-You

    2016-01-01

    Two examples of Co(II)-N-heterocyclic coordination polymers based on 1-hydroxyethylidenediphosphonic acid (H5L = CH3C(OH)(PO3H2)2), namely 0.5(H3NCH2CH2NH3)·[Co6(Cl2)(H3L)2(H2L)(HL)(2,2‧-bipy)6] 1 and 2(NH4)·[Co3(HL)2(H2O)2(phen)2]·2(H2O) 2, have been solvothermally obtained by introducing the second ligands 2,2‧-bipyridine/1,10-phenanthroline (2,2‧-bipy/phen) and characterized by powder X-ray diffraction (PXRD), elemental analysis, IR, TG-DSC. The single-crystal X-ray diffractions show that compound 1 possesses a 0-D structure with hexa-nuclear cluster [Co6(O-P-O)8] built through single/double O-P-O bridges and compound 2 displays a 1-D ladder-like chain structure with magnetic topology building blocks [Co4(O-P-O)4]n. Then H-bonding and π-π stacking interactions further expand the two low-dimensional structures into three-dimensional supramolecular frameworks. Fluorescent measurements reveal that both the maximum emission peaks of 1-2 are centered at 423 nm, mainly deriving from intraligand π*-π transition state of N-heterocyclic ligand 2,2‧-bipy/phen, respectively. Magnetism data indicate that 1 exhibits antiferromagnetic behavior within hexa-nuclear Co(II) clusters, while 2 shows weak ferromagnetic interactions in 1-D topology Co(II)-chain, showing promising potential as magnetic materials.

  17. Aromatic carboxylate effect on dimensionality of three bis(benzimidazole)-based cobalt(II) coordination polymers: Syntheses, structures and properties

    International Nuclear Information System (INIS)

    Zhang, Ju-Wen; Gong, Chun-Hua; Hou, Li-Li; Tian, Ai-Xiang; Wang, Xiu-Li

    2013-01-01

    Three new metal-organic coordination polymers [Co(4-bbc) 2 (bbbm)] (1), [Co(3,5-pdc)(bbbm)]·2H 2 O (2) and [Co(1,4-ndc)(bbbm)] (3) (4-Hbbc=4-bromobenzoic acid, 3,5-H 2 pdc=3,5-pyridinedicarboxylic acid, 1,4-H 2 ndc=1,4-naphthalenedicarboxylic acid and bbbm=1,1-(1,4-butanediyl)bis-1H-benzimidazole) were hydrothermally synthesized and structurally characterized. Polymer 1 is a 1D chain formed by the bbbm ligands and Co II ions. Polymer 2 exhibits a 2D network with a (3·4·5)(3 2 ·4·5·6 2 ·7 4 ) topology. Polymer 3 possesses a 3D three-fold interpenetrating framework. The versatile structures of title polymers indicate that the aromatic carboxylates have an important influence on the dimensionality of 1–3. Moreover, the thermal stability, electrochemical and luminescent properties of 1–3 were investigated. - graphical abstract: Three bis(benzimidazole)-based cobalt(II) coordination polymers tuned by aromatic carboxylates were hydrothermally synthesized and structurally characterized. The aromatic carboxylates play a key role in the dimensionality of three polymers. The electrochemical and luminescent properties of three polymers were investigated. Display Omitted - Highlights: • Three bis(benzimidazole)-based cobalt(II) coordination polymers tuned by aromatic carboxylates were obtained. • The aromatic carboxylates have an important influence on the dimensionality of three polymers. • The electrochemical and luminescent properties of three polymers were investigated

  18. Spin resonance with trapped ions

    Energy Technology Data Exchange (ETDEWEB)

    Wunderlich, Ch; Balzer, Ch; Hannemann, T; Mintert, F; Neuhauser, W; Reiss, D; Toschek, P E [Institut fuer Laser-Physik, Universitaet Hamburg, Jungiusstrasse 9, 20355 Hamburg (Germany)

    2003-03-14

    A modified ion trap is described where experiments (in particular related to quantum information processing) that usually require optical radiation can be carried out using microwave or radio frequency electromagnetic fields. Instead of applying the usual methods for coherent manipulation of trapped ions, a string of ions in such a modified trap can be treated like a molecule in nuclear magnetic resonance experiments taking advantage of spin-spin coupling. The collection of trapped ions can be viewed as an N-qubit molecule with adjustable spin-spin coupling constants. Given N identically prepared quantum mechanical two-level systems (qubits), the optimal strategy to estimate their quantum state requires collective measurements. Using the ground state hyperfine levels of electrodynamically trapped {sup 171}Yb{sup +}, we have implemented an adaptive algorithm for state estimation involving sequential measurements on arbitrary qubit states.

  19. Spin resonance with trapped ions

    International Nuclear Information System (INIS)

    Wunderlich, Ch; Balzer, Ch; Hannemann, T; Mintert, F; Neuhauser, W; Reiss, D; Toschek, P E

    2003-01-01

    A modified ion trap is described where experiments (in particular related to quantum information processing) that usually require optical radiation can be carried out using microwave or radio frequency electromagnetic fields. Instead of applying the usual methods for coherent manipulation of trapped ions, a string of ions in such a modified trap can be treated like a molecule in nuclear magnetic resonance experiments taking advantage of spin-spin coupling. The collection of trapped ions can be viewed as an N-qubit molecule with adjustable spin-spin coupling constants. Given N identically prepared quantum mechanical two-level systems (qubits), the optimal strategy to estimate their quantum state requires collective measurements. Using the ground state hyperfine levels of electrodynamically trapped 171 Yb + , we have implemented an adaptive algorithm for state estimation involving sequential measurements on arbitrary qubit states

  20. MIDAS phase II. A program for the modal analysis of structures

    International Nuclear Information System (INIS)

    Durrans, R.F.

    1980-10-01

    The application of Modal Analysis to the experimental characterisation of structures is described. A program MIDAS (Modal Identification for the Dynamic Analysis of Structures) has been developed at B.N.L. to perform this function and this report presents a full description of its use. The structures within the coolant circuits of nuclear reactors must be designed to withstand large flow and acoustic forces. (U.K.)