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Sample records for two-nucleon structure form

  1. Properties of simultaneous and sequential two-nucleon transfer

    International Nuclear Information System (INIS)

    Pinkston, W.T.; Satchler, G.R.

    1982-01-01

    Approximate forms of the first- and second-order distorted-wave Born amplitudes are used to study the overall structure, particularly the selection rules, of the amplitudes for simultaneous and sequential transfer of two nucleons. The role of the spin-state assumed for the intermediate deuterons in sequential (t, p) reactions is stressed. The similarity of one-step and two-step amplitudes for (α, d) reactions is exhibited, and the consequent absence of any obvious J-dependence in their interference is noted. (orig.)

  2. The two-nucleon system above pion threshold

    International Nuclear Information System (INIS)

    Poepping, H.; Sauer, P.U.; Zhang Xizhen

    1987-01-01

    A force model is presented for the description of the two-nucleon system below and above pion threshold and its coupled inelastic channels with one pion. It uses Δ-isobar and pion degrees of freedom in addition to the nucleonic one. The force model is based on a hamiltonian approach within the framework of noncovariant quantum mechanics. It extends the traditional approach with purely nucleonic potentials in isospin-triplet partial waves. It is constructed to remain valid up to 500 MeV c.m. energy. The characteristics of the force model is its mechanism for pion production and pion absorption which is mediated by the Δ-isobar. Even without any fit of phenomenological parameters the force model is able to account for the experimental data of elastic nucleon-nucleon scattering' of the inelastic reactions pp ↔ π + d and of elastic pion-deuteron scattering with satisfactory accuracy. No need for the introduction of dibaryon degrees of freedom has been found yet. The force model is a realistic one in the two-nucleon system. In many-nucleon systems it forms the unifying basis for a microscopic description of nuclear structure and nuclear reactions at low and intermediate energies. (orig.)

  3. sdg Interacting boson model: two nucleon transfer

    International Nuclear Information System (INIS)

    Devi, Y.D.; Kota, V.K.B.

    1996-01-01

    A brief overview of the sdg interacting boson model (sdg IBM) is given. The two examples: (i) spectroscopic properties (spectra, B(E2)s, B(E4)s etc) of the rotor-γ unstable transitional Os-Pt isotopes and (ii) the analytical formulation of two nucleon transfer spectroscopic factors and sum-rule quantities are described in detail. They demonstrate that sdg IBM can be employed for systematic description of spectroscopic properties of nuclei and that large number of analytical formulas, which facilitate rapid analysis of data and provide a clear insight into the underlying structures, can be derived using sdg IBM dynamical symmetries respectively. (author). 24 refs., 5 figs., 3 tabs

  4. Parity violation in two-nucleon systems

    Energy Technology Data Exchange (ETDEWEB)

    Liu, C.-P., E-mail: cpliu@mail.ndhu.edu.tw [National Dong Hwa University, Department of Physics (China)

    2013-03-15

    Nuclear few-body systems become attractive avenues for the study of low-energy parity violation because experiments start to meet the precision requirements and theoretical calculations can be performed reliably. In this talk, an attempt of parametrizing low-energy parity-violating observables by the Danilov parameters will be introduced. Analyses of two-nucleon observables, based on the modern phenomenological potentials or the one of effective field theory, will be discussed.

  5. Parity nonconservation in two-nucleon systems

    International Nuclear Information System (INIS)

    Nagle, D.E.

    1975-01-01

    The observation of a violation of the parity symmetry in two-nucleon systems implies the presence of a weak hadronic force. The positive effect reported by Lobashov et al. in the reaction np → dγ, for the circular polarization of the gamma ray, would imply a large value for the parity nonconserving (PNC) amplitude. A transmission experiment has been undertaken for 15-MeV longitudinally polarized protons on hydrogen. A transmission experiment for 6-GeV polarized protons on Be and on H 2 O is in progress at the ZGS at Argonne National Laboratory. The current results of the latter two experiments are summarized, and the relation to theoretical calculations is discussed. (2 figures, 1 table) (U.S.)

  6. Phenomenological two-nucleon interaction operator

    International Nuclear Information System (INIS)

    Lagaris, I.E.; Pandharipande, V.R.

    1981-01-01

    We report a phenomenological two-nucleon interaction operator obtained by fitting the nucleon-nucleon phase shifts up to 425 MeV in S, P, D and F waves, and the deuteron properties. The operator has the standard eight potentials associated with the two-body operators 1, sigma 1 x sigma 2 , tau 1 x tau 2 , sigma 1 x sigma 2 tau 1 x tau 2 , S 12 , S 12 tau 1 x tau 2 , L x S and L x Stau 2 ; and six phenomenological potentials associated with operators L 2 , L 2 sigma 1 x sigma 2 , L 2 tau 1 x tau 2 , L 2 sigma 1 x sigma 2 tau 1 xtau 2 (L x S) 2 tau 1 x tau 2 . The six quadratic L terms are relatively weak, and are chosen in order to make many-body calculations with this operator simpler. (orig.)

  7. Relations between the simultaneous and sequential transfer of two nucleons

    International Nuclear Information System (INIS)

    Satchler, G.R.

    1982-01-01

    The transfer of two nucleons between projectile and target in a direct or peripheral reaction such as (p,t) or ( 16 O, 14 C) may occur in one-step or two-steps. These we refer to as simultaneous and sequential transfers, respectively. In the former, the interaction acts once and both nucleons are transferred. In the latter, the interaction acts once to transfer one nucleon, the system then propagates in one or more intermediate states and is followed by a second action of the interaction to transfer the second nucleon. This process may be symbolized for the examples as (p,d; d,t) and ( 16 O, 15 N; 15 N, 14 C), implying the intermediate formation of a deuteron or the nucleus 15 N. In terms of a perturbation theory expansion, such as the distorted-wave Born series, simultaneous transfer is possible in first order while sequential transfer requires second order. The nuclear forces are predominantly two-body in character; hence, in first-order only one of the two nucleons experiences an interaction. The possibility of finding that the other nucleon has also transferred arises only because its state within the projectile is not orthogonal to the state in the target into which it transfers. In the two-step process each nucleon is transferred under the direct influence of an interaction with the target. The one-step and two-step amplitudes are frequently comparable in magnitude for light-ion reactions while the two-step may dominate in reactions with heavy ions. Our purpose here is to gain some insight into the relationship between the two amplitudes by using a simple approximate form of the theory. For simplicity, we shall discuss a light-ion reaction and, to be specific, we choose the (t,p) reaction (or the inverse (p,t) reaction)

  8. Relations between the simultaneous and sequential transfer of two nucleons

    International Nuclear Information System (INIS)

    Satchler, G.R.

    1982-01-01

    The author discusses the perturbative treatment of simultaneous and sequential two-nucleon transfer reactions with special regards to the DWBA. As examples the (t,p), (p,t), and (α,d) reactions are considered. (HSI)

  9. Off-energy-shell variations of two-nucleon transition matrix and three-nucleon problem

    International Nuclear Information System (INIS)

    Stingl, M.; Sauer, P.U.

    1975-01-01

    For a schematic three-nucleon problem, approximate analytic expressions are derived for the functional derivatives of measurable three-particle quantities with respect to off-shell variations of the triplet-s two-nucleon transition matrix. Those quantities include neutron-deuteron scattering lengths, trinucleon binding energies, and the 3 He charge form-factor minimum; correlations between off-shell changes in the latter two are discussed. An indication is given how results of this kind may be to decide whether or not a given set of discrepancies between calculated and experimental three-nucleon observables can be reconciled in terms of off-shell variations of a nonretarded hermitean two-nucleon interaction. The treatment is not restricted to special classes of phase-shift equivalent potentials or phase-shift preserving transformations but instead makes use of a systematic parameterization of off-shell variations in terms of symmetric rational approximants of increasing order

  10. Hard breakup of two nucleons from the 3He nucleus

    International Nuclear Information System (INIS)

    Sargsian, Misak M.; Granados, Carlos

    2009-01-01

    We investigate a large angle photodisintegration of two nucleons from the 3 He nucleus within the framework of the hard rescattering model (HRM). In the HRM a quark of one nucleon knocked out by an incoming photon rescatters with a quark of the other nucleon leading to the production of two nucleons with large relative momentum. Assuming the dominance of the quark-interchange mechanism in a hard nucleon-nucleon scattering, the HRM allows the expression of the amplitude of a two-nucleon breakup reaction through the convolution of photon-quark scattering, NN hard scattering amplitude, and nuclear spectral function, which can be calculated using a nonrelativistic 3 He wave function. The photon-quark scattering amplitude can be explicitly calculated in the high energy regime, whereas for NN scattering one uses the fit of the available experimental data. The HRM predicts several specific features for the hard breakup reaction. First, the cross section will approximately scale as s -11 . Second, the s 11 weighted cross section will have the shape of energy dependence similar to that of s 10 weighted NN elastic scattering cross section. Also one predicts an enhancement of the pp breakup relative to the pn breakup cross section as compared to the results from low energy kinematics. Another result is the prediction of different spectator momentum dependencies of pp and pn breakup cross sections. This is due to the fact that the same-helicity pp-component is strongly suppressed in the ground state wave function of 3 He. Because of this suppression the HRM predicts significantly different asymmetries for the cross section of polarization transfer NN breakup reactions for circularly polarized photons. For the pp breakup this asymmetry is predicted to be zero while for the pn it is close to (2/3).

  11. Two-nucleon bound states in quenched lattice QCD

    International Nuclear Information System (INIS)

    Yamazaki, T.; Kuramashi, Y.; Ukawa, A.

    2011-01-01

    We address the issue of bound state in the two-nucleon system in lattice QCD. Our study is made in the quenched approximation at the lattice spacing of a=0.128 fm with a heavy quark mass corresponding to m π =0.8 GeV. To distinguish a bound state from an attractive scattering state, we investigate the volume dependence of the energy difference between the ground state and the free two-nucleon state by changing the spatial extent of the lattice from 3.1 fm to 12.3 fm. A finite energy difference left in the infinite spatial volume limit leads us to the conclusion that the measured ground states for not only spin triplet but also singlet channels are bounded. Furthermore the existence of the bound state is confirmed by investigating the properties of the energy for the first excited state obtained by a 2x2 diagonalization method. The scattering lengths for both channels are evaluated by applying the finite volume formula derived by Luescher to the energy of the first excited states.

  12. Relations between the simultaneous and sequential transfer of two nucleons

    International Nuclear Information System (INIS)

    Satchler, G.R.

    1982-01-01

    The transfer of two nucleons between projectile and target in a direct or peripheral reaction such as (p,t) or ( 16 O, 14 C) may occur in one-step or two-steps. These we refer to as simultaneous and sequential transfers, respectively. In the former, the interaction acts once and both nucleons are transferred. In the latter, the interaction acts once to transfer one nucleon, the system then propagates in one or more intermediate states and is followed by a second action of the interaction to transfer the second nucleon. This process may be symbolized for the above examples as (p,d;d,t) and ( 16 O, 15 N; 15 N, 14 C), implying the intermediate formation of a deuteron or the nucleus 15 N. (Of course, the intermediate system may exist in more than one state of excitation). For simplicity, the (t,p) reaction is chosen to illustrate the theory

  13. Microscopic calculation of absolute values of two-nucleon transfer cross sections

    International Nuclear Information System (INIS)

    Potel, G.; Bayman, B. F.; Barranco, F.

    2009-01-01

    Arguably, the greatest achievement of many-body physics in the fifties was that of providing the basis for a complete description and a thorough understanding of superconductivity in metals. At the basis of it one finds BCS theory and Josephson effect. The first recognized the central role played by the appearance of a macroscopic coherent field -usually viewed as a condensate of strongly overlapping Cooper pairs-, the quasiparticle vacuum. The second realized that a true gap is not essential for such a state of matter to exist, but rather a finite expectation value of the pair field. Consequently, the specific probe to study the superconducting state is Cooper pair tunneling. Important progress in the understanding of pairing in atomic nuclei may arise from the systematic study of two-particle transfer reactions. Although this subject of research started about the time of the BCS papers, the quantitative calculation of absolute cross sections taking properly into account the full non-locality of the Cooper pairs (correlation length much larger than nuclear dimensions) is still an open problem. We present in this talk the results obtained within a second order DWBA framework for two- nucleon transfer reactions around the Coulomb barrier induced both by heavy and light ions. The calculations were done using a computer code developed for this purpose including the sequential and simultaneous contributions to the process, with microscopic form factors which take into account the relevant structure aspects of the process, such as the nature of the single-particle wavefunctions, the spectroscopic factors, and the interaction potential responsible for the transfer. Reasonable agreement with the experimental absolute values of the differential cross section is obtained without any parameter adjustment (see Figure 1).(author)

  14. Proceedings of the workshop on two-nucleon system

    International Nuclear Information System (INIS)

    Kawaguchi, Masaaki; Namiki, Mikio; Fukawa, Mineo; Masaike, Akira

    1980-08-01

    The workshop on two nucleon system started its works four years ago to promote the experiment project on nucleon-nucleon system in the National Laboratory for High Energy Physics by the close cooperation of experimenters and theorists. In particular, several proposals have been made about the experiments using the polarized targets of hydrogen and deuterium, the spectrometers of large solid angle and others, and the investigation into them have been forwarded. It was decided to publish the results of the fourth meeting held in the National Laboratory for High Energy Physics on October 19 and 20, 1979, as the interim report, summarizing the contents. Some of the initial objectives have not been realized yet, but the data have been produced gradually from the experiments in the National Laboratory for High Energy Physics, and are contributing to various analyses. This report is composed of the physics of nucleon-nucleon systems and anti-nucleon-nucleon systems, the results of experiments and the projects corresponding to them, and the hypothetic round-table talk on the points which this workshop considers as problematic and the views of outside researchers on the National Laboratory for High Energy Physics. Finally, the materials distributed at the time of the meeting are added for reference as the appendix. Some numerical values are mutually different, but adjustment was not made. (Kako, I.)

  15. Microscopically-constrained Fock energy density functionals from chiral effective field theory. I. Two-nucleon interactions

    International Nuclear Information System (INIS)

    Gebremariam, B.; Bogner, S.K.; Duguet, T.

    2011-01-01

    The density matrix expansion (DME) of Negele and Vautherin is a convenient tool to map finite-range physics associated with vacuum two- and three-nucleon interactions into the form of a Skyrme-like energy density functional (EDF) with density-dependent couplings. In this work, we apply the improved formulation of the DME proposed recently in (arXiv:0910.4979) by Gebremariam et al. to the non-local Fock energy obtained from chiral effective field theory (EFT) two-nucleon (NN) interactions at next-to-next-to-leading-order (N 2 LO). The structure of the chiral interactions is such that each coupling in the DME Fock functional can be decomposed into a coupling constant arising from zero-range contact interactions and a coupling function of the density arising from the universal long-range pion exchanges. This motivates a new microscopically-guided Skyrme phenomenology where the density-dependent couplings associated with the underlying pion-exchange interactions are added to standard empirical Skyrme functionals, and the density-independent Skyrme parameters subsequently refit to data. A link to a downloadable Mathematica notebook containing the novel density-dependent couplings is provided.

  16. Comparison of different source calculations in two-nucleon channel at large quark mass

    Science.gov (United States)

    Yamazaki, Takeshi; Ishikawa, Ken-ichi; Kuramashi, Yoshinobu

    2018-03-01

    We investigate a systematic error coming from higher excited state contributions in the energy shift of light nucleus in the two-nucleon channel by comparing two different source calculations with the exponential and wall sources. Since it is hard to obtain a clear signal of the wall source correlation function in a plateau region, we employ a large quark mass as the pion mass is 0.8 GeV in quenched QCD. We discuss the systematic error in the spin-triplet channel of the two-nucleon system, and the volume dependence of the energy shift.

  17. Analytical expressions for two-nucleon transfer spectroscopic factors in sdg interacting boson model

    International Nuclear Information System (INIS)

    Devi, Y.D.; Kota, V.K.B.

    1991-01-01

    Analytical expressions for two-nucleon (l = 0,2 and 4) transfer spectroscopic factors are derived in the SU sdg (3) limit of the sdg interacting boson model. In addition, large N (boson number) limit expressions for the ratio of summed l = 0 transfer strength to excited 0 + states to that of ground state are derived in all the symmetry limits of the sdg model. Some comparisons with data are made. (author)

  18. Analytical expressions for two-nucleon transfer spectroscopic factors in sdg interacting boson model

    Energy Technology Data Exchange (ETDEWEB)

    Devi, Y.D.; Kota, V.K.B. (Physical Research Lab., Ahmedabad (India))

    1991-11-01

    Analytical expressions for two-nucleon (l = 0,2 and 4) transfer spectroscopic factors are derived in the SU{sub sdg}(3) limit of the sdg interacting boson model. In addition, large N (boson number) limit expressions for the ratio of summed l = 0 transfer strength to excited 0{sup +} states to that of ground state are derived in all the symmetry limits of the sdg model. Some comparisons with data are made. (author).

  19. Two-nucleon emitters within a pseudostate method: The case of 6Be and 16Be

    Science.gov (United States)

    Casal, J.

    2018-03-01

    Background: Since the first experimental observation, two-nucleon radioactivity has gained renewed attention since the early 2000s. The 6Be system is the lightest two-proton ground-state emitter, while 16Be was recently proposed to be the first two-neutron ground-state emitter ever observed. A proper understanding of their properties and decay modes requires a reasonable description of the three-body continuum. Purpose: Study the ground-state properties of 6Be and 16Be within a general three-body model and investigate their nucleon-nucleon correlations in the continuum. Method: The pseudostate (PS) method in hyperspherical coordinates, using the analytical transformed harmonic oscillator (THO) basis for three-body systems, is used to construct the 6Be and 16Be ground-state wave functions. These resonances are approximated as a stable PS around the known two-nucleon separation energy. Effective core-N potentials, constrained by the available experimental information on the binary subsystems 5Li and 15Be, are employed in the calculations. Results: The ground state of 16Be is found to present a strong dineutron configuration, with the valence neutrons occupying mostly an l =2 state relative to the core. The results are consistent with previous R -matrix calculations for the actual continuum. The case of 6Be shows a clear symmetry with respect to its mirror partner, the two-neutron halo 6He: The diproton configuration is dominant, and the valence protons occupy an l =1 orbit. Conclusions: The PS method is found to be a suitable tool in describing the properties of unbound core+N +N ground states. For both 16Be and 6Be, the results are consistent with previous theoretical studies and confirm the dominant dinucleon configuration. This favors the picture of a correlated two-nucleon emission.

  20. Nanodiamond particles forming photonic structures

    International Nuclear Information System (INIS)

    Grichko, Varvara; Tyler, Talmage; Grishko, Victor I; Shenderova, Olga

    2008-01-01

    Colloid suspensions of irregularly shaped, highly charged detonation nanodiamond particles are found to have unexpected optical properties, similar to those of photonic crystals. This finding is all the more surprising since the particles used in this work are far more polydisperse than those typically forming photonic crystals. Intensely iridescent structures have been fabricated using the centrifugation of aqueous suspensions of nanodiamonds

  1. Nanodiamond particles forming photonic structures

    Energy Technology Data Exchange (ETDEWEB)

    Grichko, Varvara; Tyler, Talmage; Grishko, Victor I; Shenderova, Olga [International Technology Center, 8100 Brownleigh Drive, Suite 120, Raleigh, NC 27617 (United States)], E-mail: oshenderova@itc-inc.org

    2008-06-04

    Colloid suspensions of irregularly shaped, highly charged detonation nanodiamond particles are found to have unexpected optical properties, similar to those of photonic crystals. This finding is all the more surprising since the particles used in this work are far more polydisperse than those typically forming photonic crystals. Intensely iridescent structures have been fabricated using the centrifugation of aqueous suspensions of nanodiamonds.

  2. Spin of two-nucleon system and nucleon-antinucleon combination in the S-state

    International Nuclear Information System (INIS)

    Baranik, A.T.; El-Naghy, A.; Ramadan, S.

    1988-08-01

    The spin of the two nucleon combination was studied. It was found that the resultant combination could be treated as a boson with spin one or zero, and the spin one state is more stable than the spin zero state. In the case of nucleon-antinucleon combination the spin zero state is more stable than the spin one state. The approach succeeded in describing the general features of the nucleon-nucleon and nucleon antinucleon scattering and polarization. (author). 3 refs, 4 figs

  3. Two-nucleon electromagnetic current in chiral effective field theory: One-pion exchange and short-range contributions

    International Nuclear Information System (INIS)

    Koelling, S.; Epelbaum, E.; Krebs, H.; Meissner, U.-G.

    2011-01-01

    We derive the leading one-loop contribution to the one-pion exchange and short-range two-nucleon electromagnetic current operator in the framework of chiral effective field theory. The derivation is carried out using the method of unitary transformation. Explicit results for the current and charge densities are given in momentum and coordinate space.

  4. Two-nucleon higher partial-wave scattering from lattice QCD

    Directory of Open Access Journals (Sweden)

    Evan Berkowitz

    2017-02-01

    Full Text Available We present a determination of nucleon-nucleon scattering phase shifts for ℓ≥0. The S, P, D and F phase shifts for both the spin-triplet and spin-singlet channels are computed with lattice Quantum ChromoDynamics. For ℓ>0, this is the first lattice QCD calculation using the Lüscher finite-volume formalism. This required the design and implementation of novel lattice methods involving displaced sources and momentum-space cubic sinks. To demonstrate the utility of our approach, the calculations were performed in the SU(3-flavor limit where the light quark masses have been tuned to the physical strange quark mass, corresponding to mπ=mK≈800 MeV. In this work, we have assumed that only the lowest partial waves contribute to each channel, ignoring the unphysical partial wave mixing that arises within the finite-volume formalism. This assumption is only valid for sufficiently low energies; we present evidence that it holds for our study using two different channels. Two spatial volumes of V≈(3.5 fm3 and V≈(4.6 fm3 were used. The finite-volume spectrum is extracted from the exponential falloff of the correlation functions. Said spectrum is mapped onto the infinite volume phase shifts using the generalization of the Lüscher formalism for two-nucleon systems.

  5. On some aspects of the relativistic description of the two-nucleon system

    International Nuclear Information System (INIS)

    Zuilhof, M.

    1981-01-01

    It has been shown that the Bethe-Salpeter equation (BSE) with a one-boson exchange (OBE) as the driving force is capable of giving a reasonable description of the two-nucleon system. They find it necessary to use a pseudo-vector (PV) pion-nucleon coupling, instead of the usual pseudo-scalar (PS) coupling, due to the very strong effects induced by the coupling of positive and negative-energy states in the latter case. Within such a field-theoretic model it is possible to study the electro-magnetic effects in a consistent way and the results, which are described in this thesis, do not deviate markedly from those calculated within a nonrelativistic model without corrections. A detailed analysis of the perturbative approach, is given and reveals both for PV and for PS coupling that there are effects which compensate the accepted contributions substantially. In particular, it is important to include the corrections due to special relativity in a consistent way. In addition the convergence of the quasipotential approach to the BSE has also been studied by adding higher order one-loop corrections. In general the author finds that the inclusion of corrections from the two-pion direct-box diagram to the driving force does not yield phase shifts close to the ones obtained from the BSE. The crossed-box effects are also of interest because one expects that there are cancellations with the direct-box diagram. This turns out not to be the case. Although there are essentially no problems in including these contributions in the description of the nucleon-nucleon interaction within the Blankenbeckler and Sugar framework, difficulties arise in the evaluation of the electromagnetic deuteron vertex function. (Auth.)

  6. Towards Free-Form Kinetic Structures

    DEFF Research Database (Denmark)

    Parigi, Dario; Kirkegaard, Poul Henning

    2012-01-01

    of pin-slot paths starting from the local displacements of element [2] [3]. In the design of kinetic structures, in particular when complex three dimensional and non regular configurations are involved, the functionality is frequently related to a global displacement capability of the assembly rather...... for the generation of free-form kinetic structures....

  7. Structural optimization of free-form reciprocal structures

    DEFF Research Database (Denmark)

    Parigi, Dario

    2014-01-01

    This paper presents an optimization algorithm for the design of structurally efficient free-form reciprocal structures. Because of the geometric complexity of reciprocal structures, only a few structural studies have been carried out so far, and we have a limited knowledge of the relation between...

  8. Structural information theory and visual form

    NARCIS (Netherlands)

    Leeuwenberg, E.L.J.; Kaernbach, C.; Schroeger, E.; Mueller, H.

    2003-01-01

    The paper attends to basic characteristics of visual form as approached by Structural information theory, or SIT, (Leeuwenberg, Van der Helm and Van Lier). The introduction provides a global survey of this approach. The main part of the paper focuses on three characteristics of SIT. Each one is made

  9. FILAMENTARY STRUCTURE OF STAR-FORMING COMPLEXES

    International Nuclear Information System (INIS)

    Myers, Philip C.

    2009-01-01

    The nearest young stellar groups are associated with 'hubs' of column density exceeding 10 22 cm -2 , according to recent observations. These hubs radiate multiple 'filaments' of parsec length, having lower column density and fewer stars. Systems with many filaments tend to have parallel filaments with similar spacing. Such 'hub-filament structure' is associated with all of the nine young stellar groups within 300 pc, forming low-mass stars. Similar properties are seen in infrared dark clouds forming more massive stars. In a new model, an initial clump in a uniform medium is compressed into a self-gravitating, modulated layer. The outer layer resembles the modulated equilibrium of Schmid-Burgk with nearly parallel filaments. The filaments converge onto the compressed clump, which collapses to form stars with high efficiency. The initial medium and condensations have densities similar to those in nearby star-forming clouds and clumps. The predicted structures resemble observed hub-filament systems in their size, shape, and column density, and in the appearance of their filaments. These results suggest that HFS associated with young stellar groups may arise from compression of clumpy gas in molecular clouds.

  10. Forming of shape memory composite structures

    DEFF Research Database (Denmark)

    Santo, Loredana; Quadrini, Fabrizio; De Chiffre, Leonardo

    2013-01-01

    A new forming procedure was developed to produce shape memory composite structures having structural composite skins over a shape memory polymer core. Core material was obtained by solid state foaming of an epoxy polyester resin with remarkably shape memory properties. The composite skin consisted...... of a two-layer unidirectional thermoplastic composite (glass filled polypropylene). Skins were joined to the foamed core by hot compression without any adhesive: a very good adhesion was obtained as experimental tests confirmed. The structure of the foam core was investigated by means of computer axial...... tomography. Final shape memory composite panels were mechanically tested by three point bending before and after a shape memory step. This step consisted of a compression to reduce the panel thickness up to 60%. At the end of the bending test the panel shape was recovered by heating and a new memory step...

  11. Testing two-nucleon transfer reaction mechanism with elementary modes of excitation in exotic nuclei

    CERN Document Server

    Broglia, R A; Idini, A; Barranco, F; Vigezzi, E

    2015-01-01

    Nuclear Field Theory of structure and reactions is confronted with observations made on neutron halo dripline nuclei, resulting in the prediction of a novel (symbiotic) mode of nuclear excitation, and on the observation of the virtual effect of the halo phenomenon in the apparently non-halo nucleus $^7$Li. This effect is forced to become real by intervening the virtual process with an external (t,p) field which, combined with accurate predictive abilities concerning the absolute differential cross section, reveals an increase of a factor 2 in the cross section due to the presence of halo ground state correlations, and is essential to reproduce the value of the observed $d \\sigma(^7$Li(t,p)$^9$Li)/d$\\Omega$.

  12. Universality of many-body two-nucleon momentum distributions: Correlated nucleon spectral function of complex nuclei

    Science.gov (United States)

    Ciofi degli Atti, Claudio; Morita, Hiko

    2017-12-01

    Background: The nuclear spectral function is a fundamental quantity that describes the mean-field and short-range correlation dynamics of nucleons embedded in the nuclear medium; its knowledge is a prerequisite for the interpretation of various electroweak scattering processes off nuclear targets aimed at providing fundamental information on strong and weak interactions. Whereas in the case of the three-nucleon and, partly, the four-nucleon systems, the spectral function can be calculated ab initio within a nonrelativistic many-body Schroedinger approach, in the case of complex nuclei only models of the correlated, high-momentum part of the spectral function are available so far. Purpose: The purpose of this paper is to present a new approach such that the spectral function for a specific nucleus can be obtained from a reliable many-body calculation based upon realistic nucleon-nucleon interactions, thus avoiding approximations leading to adjustable parameters. Methods: The expectation value of the nuclear many-body Hamiltonian, containing realistic nucleon-nucleon interaction of the Argonne family, is evaluated variationally by a normalization-conserving linked-cluster expansion and the resulting many-body correlated wave functions are used to calculate the one-nucleon and the two-nucleon momentum distributions; by analyzing the high-momentum behavior of the latter, the spectral function can be expressed in terms of a transparent convolution formula involving the relative and center-of-mass (c.m.) momentum distributions in specific regions of removal energy E and momentum k . Results: It is found that as a consequence of the factorization of the many-body wave functions at short internucleon separations, the high-momentum behavior of the two-nucleon momentum distributions in A =3 ,4 ,12 ,16 ,40 nuclei factorizes, at proper values of the relative and c.m. momenta, into the c.m. and relative momentum distributions, with the latter exhibiting a universal A

  13. High-quality two-nucleon potentials up to fifth order of the chiral expansion

    Science.gov (United States)

    Entem, D. R.; Machleidt, R.; Nosyk, Y.

    2017-08-01

    We present NN potentials through five orders of chiral effective field theory ranging from leading order (LO) to next-to-next-to-next-to-next-to-leading order (N4LO ). The construction may be perceived as consistent in the sense that the same power counting scheme as well as the same cutoff procedures are applied in all orders. Moreover, the long-range parts of these potentials are fixed by the very accurate π N low-energy constants (LECs) as determined in the Roy-Steiner equations analysis by Hoferichter, Ruiz de Elvira, and coworkers. In fact, the uncertainties of these LECs are so small that a variation within the errors leads to effects that are essentially negligible, reducing the error budget of predictions considerably. The NN potentials are fit to the world NN data below the pion-production threshold of the year 2016. The potential of the highest order (N4LO ) reproduces the world NN data with the outstanding χ2/datum of 1.15, which is the highest precision ever accomplished for any chiral NN potential to date. The NN potentials presented may serve as a solid basis for systematic ab initio calculations of nuclear structure and reactions that allow for a comprehensive error analysis. In particular, the consistent order by order development of the potentials will make possible a reliable determination of the truncation error at each order. Our family of potentials is nonlocal and, generally, of soft character. This feature is reflected in the fact that the predictions for the triton binding energy (from two-body forces only) converges to about 8.1 MeV at the highest orders. This leaves room for three-nucleon-force contributions of moderate size.

  14. Consistent, high-quality two-nucleon potentials up to fifth order of the chiral expansion

    Science.gov (United States)

    Machleidt, R.

    2018-02-01

    We present N N potentials through five orders of chiral effective field theory ranging from leading order (LO) to next-to-next-to-next-to-next-to-leading order (N4LO). The construction may be perceived as consistent in the sense that the same power counting scheme as well as the same cutoff procedures are applied in all orders. Moreover, the long-range parts of these potentials are fixed by the very accurate πN low-energy constants (LECs) as determined in the Roy-Steiner equations analysis by Hoferichter, Ruiz de Elvira and coworkers. In fact, the uncertainties of these LECs are so small that a variation within the errors leads to effects that are essentially negligible, reducing the error budget of predictions considerably. The N N potentials are fit to the world N N data below pion-production threshold of the year of 2016. The potential of the highest order (N4LO) reproduces the world N N data with the outstanding χ 2/datum of 1.15, which is the highest precision ever accomplished for any chiral N N potential to date. The N N potentials presented may serve as a solid basis for systematic ab initio calculations of nuclear structure and reactions that allow for a comprehensive error analysis. In particular, the consistent order by order development of the potentials will make possible a reliable determination of the truncation error at each order. Our family of potentials is non-local and, generally, of soft character. This feature is reflected in the fact that the predictions for the triton binding energy (from two-body forces only) converges to about 8.1 MeV at the highest orders. This leaves room for three-nucleon-force contributions of moderate size.

  15. Structural Encoding of Static Single Assignment Form

    DEFF Research Database (Denmark)

    Gal, Andreas; Probst, Christian; Franz, Michael

    2005-01-01

    Static Single Assignment (SSA) form is often used as an intermediate representation during code optimization in Java Virtual Machines. Recently, SSA has successfully been used for bytecode verification. However, constructing SSA at the code consumer is costly. SSAbased mobile code transport formats...... Java bytecode. While the resulting bytecode sequence can still be directly executed by traditional Virtual Machines, our novel VM can infer SSA form and confirm its safety with virtually no overhead....... have been shown to eliminate this cost by shifting SSA creation to the code producer. These new formats, however, are not backward compatible with the established Java class-file format. We propose a novel approach to transport SSA information implicitly through structural code properties of standard...

  16. Structure of Complex Verb Forms in Meiteilon

    Directory of Open Access Journals (Sweden)

    Lourembam Surjit Singh

    2016-12-01

    Full Text Available This piece of work proposes to descriptively investigate the structures of complex verbs in Meiteilon. The categorization of such verbs is based on the nature of semantic and syntactic functions of a lexeme or verbal lexeme. A lexeme or verbal lexeme in Meiteilon may have multifunctional properties in the nature of occurrence. Such lexical items can be co-occurred together in a phrase as single functional word. Specifically, in the co-occurrences of two lexical items, the first component of lexical items has different semantic and syntactic functions in comparison to semantic and syntactic functions of the second component of lexical items. Such co-occurrences of two lexical items are the forms of complex verb that are covered with the term complex predicate in this work. The investigation in constructing complex predicate is thoroughly presenting in this work. Keywords: Structures, complex verb, conjunct verb, compound verb, complex predicate

  17. Combustible structural composites and methods of forming combustible structural composites

    Science.gov (United States)

    Daniels, Michael A.; Heaps, Ronald J.; Steffler, Eric D.; Swank, W. David

    2013-04-02

    Combustible structural composites and methods of forming same are disclosed. In an embodiment, a combustible structural composite includes combustible material comprising a fuel metal and a metal oxide. The fuel metal is present in the combustible material at a weight ratio from 1:9 to 1:1 of the fuel metal to the metal oxide. The fuel metal and the metal oxide are capable of exothermically reacting upon application of energy at or above a threshold value to support self-sustaining combustion of the combustible material within the combustible structural composite. Structural-reinforcing fibers are present in the composite at a weight ratio from 1:20 to 10:1 of the structural-reinforcing fibers to the combustible material. Other embodiments and aspects are disclosed.

  18. METHODS OF FORMING THE STRUCTURE OF KNOWLEDGE

    Directory of Open Access Journals (Sweden)

    Tatyana A. Snegiryova

    2015-01-01

    Full Text Available The aim of the study is to describe the method of forming thestructure of knowledge of students on the basis of an integrated approach (expert, taxonomy and thesaurus and the presentation of the results of its use in the study of medical and biological physics at the Izhevsk State Medical Academy.Methods. The methods used in the work involve: an integrated approach that includes group expert method, developed by V. S. Cherepanov; taxonomy and thesaurus approach when creating a model of taxonomic structure of knowledge, as well as models of the formation of the knowledge structure.Results. The algorithm, stages and procedures of knowledge structure formation of trainees are considered in detail; the model of the given process is created; the technology of content selection of a teaching material due to the fixed time that has been released on studying of concrete discipline is shown.Scientific novelty and practical significance. Advantage of the proposed method and model of students’ knowledge structure formation consists in their flexibility: at certain adaptation they can be used while training to any discipline apart of its specificity and educational institution. Observance of all stages of the presented technology of content selection of a teaching material on the basis of an expert estimation will promote substantial increase of quality of training; make it possible to develop the unified method uniting the various points of view of teachers on knowledge formation of trainees.

  19. Forming the organizational structure for activities

    Directory of Open Access Journals (Sweden)

    U. S. Barash

    2013-04-01

    Full Text Available Purpose. Development of theoretical and methodological foundations of efficiency of freight cars operating companies in railway reform through improved management structure them. Methodology. A theoretical and methodological approach for building effective management structure of freight wagons operating companies of different ownership forms is proposed, its introduction will significantly reduce detention of cars on technical stations under loading operations and maintenance, and thereby to improve the quality parameters of rolling stock usage in reform conditions of Ukraine railway transport. Findings. An improved control mechanism of cargo transportation is developed, it is different from the existing by its adaptation to the conditions of the reformed sector and the organization of management companies which together with the Ukrainian Transport and Logistics Center (UTLC centralize management of all freight cars of domestic and foreign operating companies. Originality. It is proposed for management of cargo transportation in wagons operating companies of different ownership to organize a series of management companies that would have the right to dispose of universal cars of other domestic operating companies, being on leasehold basis, and to direct them to current and scheduled repairs by themselves; to organize the cargo transportation in wagons of domestic and foreign operating companies on a contractual terms, depending on the type and content of the contract, on the basis of additional contracts for a separate fee to perform current and scheduled repair of freight cars; the management company organizational structure is developed, it includes simultaneously two directions of activity: commercial and repair, it will reduce the stay time of rolling stock on the engineering stations during loading and in a non-operating park as far as this company will manage a significant part of the production cycle of the transportation process

  20. Tensegrity structures form, stability, and symmetry

    CERN Document Server

    Zhang, Jing Yao

    2015-01-01

    To facilitate a deeper understanding of tensegrity structures, this book focuses on their two key design problems: self-equilibrium analysis and stability investigation. In particular, high symmetry properties of the structures are extensively utilized. Conditions for self-equilibrium as well as super-stability of tensegrity structures are presented in detail. An analytical method and an efficient numerical method are given for self-equilibrium analysis of tensegrity structures: the analytical method deals with symmetric structures and the numerical method guarantees super-stability. Utilizing group representation theory, the text further provides analytical super-stability conditions for the structures that are of dihedral as well as tetrahedral symmetry. This book not only serves as a reference for engineers and scientists but is also a useful source for upper-level undergraduate and graduate students. Keeping this objective in mind, the presentation of the book is self-contained and detailed, with an abund...

  1. Forming foam structures with carbon foam substrates

    Science.gov (United States)

    Landingham, Richard L.; Satcher, Jr., Joe H.; Coronado, Paul R.; Baumann, Theodore F.

    2012-11-06

    The invention provides foams of desired cell sizes formed from metal or ceramic materials that coat the surfaces of carbon foams which are subsequently removed. For example, metal is located over a sol-gel foam monolith. The metal is melted to produce a metal/sol-gel composition. The sol-gel foam monolith is removed, leaving a metal foam.

  2. Rational design of fiber forming supramolecular structures

    Science.gov (United States)

    Wang, Benjamin K; Kanahara, Satoko M

    2016-01-01

    Recent strides in the development of multifunctional synthetic biomimetic materials through the self-assembly of multi-domain peptides and proteins over the past decade have been realized. Such engineered systems have wide-ranging application in bioengineering and medicine. This review focuses on fundamental fiber forming α-helical coiled-coil peptides, peptide amphiphiles, and amyloid-based self-assembling peptides; followed by higher order collagen- and elastin-mimetic peptides with an emphasis on chemical / biological characterization and biomimicry. PMID:27022140

  3. A possible form of the pion's structure function

    International Nuclear Information System (INIS)

    Long Ming; Huang Tao

    1986-01-01

    The pion's structure function behaviour is discussed by using the Fock state expansion of the hadronic wave function in QCD in this paper. As an example, we employ a model wave function of the Fock state in the light-cone and assume a Regge behaviour of a weight function for higher Fock states, and we get a possible form of the pion's structure function. This form is consistent with experimental data of the pion's structure function

  4. Measuring the Thermophysical and Structural Properties of Glass-Forming and Quasicrystal-Forming Liquids

    Science.gov (United States)

    Hyers, Robert W.; Bradshaw, Richard C.; Rogers, Jan R.; Gangopadhyay, Anup K.; Kelton, Ken F.

    2006-01-01

    The thermophysical properties of glass-forming and quasicrystal-forming alloys show many interesting features in the undercooled liquid range. Some of the features in the thermophysical property curves are expected to reflect changes in the structure and coordination of the liquid. These measurements require containerless processing such as electrostatic levitation to access the undercooled liquid regime. An overview of the state of the art in measuring the thermophysical properties and structure of undercooled liquid glass-forming and quasicrystal-forming alloys will be presented, along with the status of current measurements.

  5. Personification in discourse: linguistic forms, conceptual structures and communicative functions.

    NARCIS (Netherlands)

    Dorst, A.G.

    2011-01-01

    Drawing on examples from a corpus of 14 excerpts from novels, this article aims to present a systematic investigation of the different linguistic forms, conceptual structures and communicative functions of personification in discourse. The Metaphor Identification Procedure (Pragglejaz Group, 2007)

  6. Does a Structured Data Collection Form Improve The Accuracy of ...

    African Journals Online (AJOL)

    and multiple etiologies for similar presentation. Standardized forms may harmonize the initial assessment, improve accuracy of diagnosis and enhance outcomes. Objectives: To determine the extent to which use of a structured data collection form (SDCF) affected the diagnostic accuracy of AAP. Methodology: A before and ...

  7. Form-finding of shell structures generated from physical models

    NARCIS (Netherlands)

    Li, Q.; Su, Y; Wu, Y; Borgart, A.; Rots, J.G.

    2017-01-01

    Vector form intrinsic finite element is a recently developed and promising numerical method for the analysis of complicated structural behavior. Taking the cable-link element as example, the framework of the vector form intrinsic finite element is explained first. Based on this, a constant strain

  8. Geometric structures associated with a simple Cartan 3-form

    Czech Academy of Sciences Publication Activity Database

    Le, Hong-Van

    2013-01-01

    Roč. 70, August (2013), s. 205-223 ISSN 0393-0440 Institutional support: RVO:67985840 Keywords : Cartan 3-form * multi-symplectic form * G-structure Subject RIV: BA - General Mathematics Impact factor: 0.797, year: 2013 http://www.sciencedirect.com/science/article/pii/S0393044013000740

  9. Friction stir method for forming structures and materials

    Science.gov (United States)

    Feng, Zhili; David, Stan A.; Frederick, David Alan

    2011-11-22

    Processes for forming an enhanced material or structure are disclosed. The structure typically includes a preform that has a first common surface and a recess below the first common surface. A filler is added to the recess and seams are friction stir welded, and materials may be stir mixed.

  10. Transparent form-active system with structural glass

    NARCIS (Netherlands)

    Nikolaou, M.S.N.; Veer, F.A.; Eigenraam, P.

    2015-01-01

    Free-form transparent wide-span spatial structures which have being constructed so far, are based on the concept of three sets of components, the structural components, usually steel elements to ensure both compressive and tensional capacity; the glass cladding elements for expressing transparency;

  11. Nucleon structure functions, resonance form factors, and duality

    International Nuclear Information System (INIS)

    Davidovsky, V.V.; Struminsky, B.V.

    2003-01-01

    The behavior of nucleon structure functions in the resonance region is explored. For form factors that describe resonance production, expressions are obtained that are dependent on the photon virtuality Q 2 , which have a correct threshold behavior, and which take into account available experimental data on resonance decay. Resonance contributions to nucleon structure functions are calculated. The resulting expressions are used to investigate quark-hadron duality in electron-nucleon scattering by taking the example of the structure function F 2

  12. Ring and Volcano Structures Formed by a Metal Dipyrromethene Complex

    Energy Technology Data Exchange (ETDEWEB)

    Son, Seung Bae; Hahn, Jae Ryang [Chonbuk National Univ., Jeonju (Korea, Republic of); Miao, Qing; Shin, Jiyoung; Dolphin, David [Univ. of British Columbia, Columbia (Canada)

    2014-06-15

    Dichloromethane liquid droplets containing a cobalt dipyrromethene trimer deposited on a graphite surface were found to form coffee ring, toroid ring, or volcano dot structures due to the redistribution of the solute during solvent evaporation. The shapes and size distributions of the ring structures depended on the drying temperature. The shape differences were attributed to the fact that the solvent evaporation rate controlled the self-assembly process that yielded the coffee stain and pinhole structures.

  13. Structural disorder in metallic glass-forming liquids.

    Science.gov (United States)

    Pan, Shao-Peng; Feng, Shi-Dong; Wang, Li-Min; Qiao, Jun-Wei; Niu, Xiao-Feng; Dong, Bang-Shao; Wang, Wei-Min; Qin, Jing-Yu

    2016-06-09

    We investigated structural disorder by a new structural parameter, quasi-nearest atom (QNA), in atomistic configurations of eight metallic glass-forming systems generated through molecular dynamics simulations at various temperatures. Structural analysis reveals that the scaled distribution of the number of QNA appears to be an universal property of metallic liquids and the spatial distribution of the number of QNA displays to be clearly heterogeneous. Furthermore, the new parameter can be directly correlated with potential energy and structural relaxation at the atomic level. Some straightforward relationships between QNA and other properties (per-atom potential energy and α-relaxation time) are introduced to reflect structure-property relationship in metallic liquids. We believe that the new structural parameter can well reflect structure disorder in metallic liquids and play an important role in understanding various properties in metallic liquids.

  14. Calibrated and Interactive Modelling of Form-Active Hybrid Structures

    DEFF Research Database (Denmark)

    Quinn, Gregory; Holden Deleuran, Anders; Piker, Daniel

    2016-01-01

    Form-active hybrid structures (FAHS) couple two or more different structural elements of low self weight and low or negligible bending flexural stiffness (such as slender beams, cables and membranes) into one structural assembly of high global stiffness. They offer high load-bearing capacity...... software packages which introduce interruptions and data exchange issues in the modelling pipeline. The mechanical precision, stability and open software architecture of Kangaroo has facilitated the development of proof-of-concept modelling pipelines which tackle this challenge and enable powerful...... materially-informed sketching. Making use of a projection-based dynamic relaxation solver for structural analysis, explorative design has proven to be highly effective....

  15. Exploratory Topology Modelling of Form-Active Hybrid Structures

    DEFF Research Database (Denmark)

    Holden Deleuran, Anders; Pauly, Mark; Tamke, Martin

    2016-01-01

    The development of novel form-active hybrid structures (FAHS) is impeded by a lack of modelling tools that allow for exploratory topology modelling of shaped assemblies. We present a flexible and real-time computational design modelling pipeline developed for the exploratory modelling of FAHS...... that enables designers and engineers to iteratively construct and manipulate form-active hybrid assembly topology on the fly. The pipeline implements Kangaroo2's projection-based methods for modelling hybrid structures consisting of slender beams and cable networks. A selection of design modelling sketches...

  16. QuikForm: Intelligent deformation processing of structural alloys

    Energy Technology Data Exchange (ETDEWEB)

    Bourcier, R.J.; Wellman, G.W.

    1994-09-01

    There currently exists a critical need for tools to enhance the industrial competitiveness and agility of US industries involved in deformation processing of structural alloys. In response to this need, Sandia National Laboratories has embarked upon the QuikForm Initiative. The goal of this program is the development of computer-based tools to facilitate the design of deformation processing operations. The authors are currently focusing their efforts on the definition/development of a comprehensive system for the design of sheet metal stamping operations. The overall structure of the proposed QuikForm system is presented, and the focus of their thrust in each technical area is discussed.

  17. New forms of inequality and structures of glam-capitalism

    OpenAIRE

    IVANOV DMITRY

    2016-01-01

    The long history of capitalism can be interpreted as an evolution driven by permanently mutating socioeconomic structures. The article is devoted to new forms of inequality that emerged during the postindustrial phase of the capitalism evolution and increase the structural complexity of contemporary societies. The spatial configuration of inequality transforms while globalization has resulted not in the ‘world society’ but rather in a transnational network of the globality enclaves: the large...

  18. Decision structures in franchise systems of the plural form

    OpenAIRE

    Kranz, Sebastian; Lewin-Solomons, Shira B.

    2008-01-01

    Many successful franchise chains directly own a positive fraction of stores --- a structure referred to as plural form. We propose that this ownership structure is chosen as a commitment not to expropriate franchisees. The theoretical model is based on an empirical analysis of contract and interview data from the US fast-food sector and well known stylized facts: First, franchisees typically have strong contractual obligations to implement activities selected by the chain. Second, franchisees...

  19. Probabilistic Seismic Performance Model for Tunnel Form Concrete Building Structures

    Directory of Open Access Journals (Sweden)

    S. Bahram Beheshti Aval

    2016-12-01

    Full Text Available Despite widespread construction of mass-production houses with tunnel form structural system across the world, unfortunately no special seismic code is published for design of this type of construction. Through a literature survey, only a few studies are about the seismic behavior of this type of structural system. Thus based on reasonable numerical results, the seismic performance of structures constructed with this technique considering the effective factors on structural behavior is highly noteworthy in a seismic code development process. In addition, due to newness of this system and observed damages in past earthquakes, and especially random nature of future earthquakes, the importance of probabilistic approach and necessity of developing fragility curves in a next generation Performance Based Earthquake Engineering (PBEE frame work are important. In this study, the seismic behavior of 2, 5 and 10 story tunnel form structures with a regular plan is examined. First, the performance levels of these structures under the design earthquake (return period of 475 years with time history analysis and pushover method are assessed, and then through incremental dynamic analysis, fragility curves are extracted for different levels of damage in walls and spandrels. The results indicated that the case study structures have high capacity and strength and show appropriate seismic performance. Moreover, all three structures subjected were in immediate occupancy performance level.

  20. Form factors and structure functions of hadrons in parton model

    International Nuclear Information System (INIS)

    Volkonskij, N.Yu.

    1979-01-01

    The hadron charge form factors and their relation to the deep-inelastic lepton-production structure functions in the regions of asymptotically high and small momentum transfer Q 2 are studied. The nucleon and pion charge radii are calculated. The results of calculations are in good agreement with the experimental data. The K- and D-meson charge radii are estimated. In the region of asymptotically high Q 2 the possibility of Drell-Yan-West relation violation is analyzed. It is shown, that for pseudoscalar mesons this relation is violated. The relation between the proton and neutron form factor asymptotics is obtained

  1. Multi-Scalar Modelling for Free-form Timber Structures

    DEFF Research Database (Denmark)

    Poinet, Paul; Nicholas, Paul; Tamke, Martin

    2016-01-01

    .The research explores the design probe of free-form structures composed of glue-laminated timber beams and looks at the different types of data that need to be shared among each discipline and across multiple scales from which different levels of resolution can be defined. A particular focus lies...... in the segmentation strategy of glue-laminated timber structures that depend on structural requirements and the different types of constraints related to fabrication, transportation and assembly. Where current working practices decouple segmentation processes within a discrete digital workflow, this research aims...... and techniques as a means to work within a continuous design environment in which an abstract network of timber beams is iteratively updated through geometrical and structural optimizations at different levels of resolution....

  2. Salt-occluded zeolite waste forms: Crystal structures and transformability

    International Nuclear Information System (INIS)

    Richardson, J.W. Jr.

    1996-01-01

    Neutron diffraction studies of salt-occluded zeolite and zeolite/glass composite samples, simulating nuclear waste forms loaded with fission products, have revealed complex structures, with cations assuming the dual roles of charge compensation and occlusion (cluster formation). These clusters roughly fill the 6--8 angstrom diameter pores of the zeolites. Samples are prepared by equilibrating zeolite-A with complex molten Li, K, Cs, Sr, Ba, Y chloride salts, with compositions representative of anticipated waste systems. Samples prepared using zeolite 4A (which contains exclusively sodium cations) as starting material are observed to transform to sodalite, a denser aluminosilicate framework structure, while those prepared using zeolite 5A (sodium and calcium ions) more readily retain the zeolite-A structure. Because the sodalite framework pores are much smaller than those of zeolite-A, clusters are smaller and more rigorously confined, with a correspondingly lower capacity for waste containment. Details of the sodalite structures resulting from transformation of zeolite-A depend upon the precise composition of the original mixture. The enhanced resistance of salt-occluded zeolites prepared from zeolite 5A to sodalite transformation is thought to be related to differences in the complex chloride clusters present in these zeolite mixtures. Data relating processing conditions to resulting zeolite composition and structure can be used in the selection of processing parameters which lead to optimal waste forms

  3. Cellular structure formed by ion-implantation-induced point defect

    International Nuclear Information System (INIS)

    Nitta, N.; Taniwaki, M.; Hayashi, Y.; Yoshiie, T.

    2006-01-01

    The authors have found that a cellular defect structure is formed on the surface of Sn + ion implanted GaSb at a low temperature and proposed its formation mechanism based on the movement of the induced point defects. This research was carried out in order to examine the validity of the mechanism by clarifying the effect of the mobility of the point defects on the defect formation. The defect structure on the GaSb surfaces implanted at cryogenic temperature and room temperature was investigated by scanning electron microscopy (SEM) and cross-sectional transmission electron microscopy (TEM) observation. In the sample implanted at room temperature, the sponge-like structure (a pileup of voids) was formed and the cellular structure, as observed at a low temperature, did not develop. This behavior was explained by the high mobility of the vacancies during implantation at room temperature, and the proposed idea that the defect formation process is dominated by the induced point defects was confirmed

  4. Structure of the orthorhombic form of human inosine triphosphate pyrophosphatase

    International Nuclear Information System (INIS)

    Porta, Jason; Kolar, Carol; Kozmin, Stanislav G.; Pavlov, Youri I.; Borgstahl, Gloria E. O.

    2006-01-01

    X-ray crystallographic analysis of human inosine triphosphate pyrophosphohydrolase provided the secondary structure and active-site structure at 1.6 Å resolution in an orthorhombic crystal form. The structure gives a framework for future structure–function studies employing site-directed mutagenesis and for the identification of substrate/product-binding sites. The structure of human inosine triphosphate pyrophosphohydrolase (ITPA) has been determined using diffraction data to 1.6 Å resolution. ITPA contributes to the accurate replication of DNA by cleansing cellular dNTP pools of mutagenic nucleotide purine analogs such as dITP or dXTP. A similar high-resolution unpublished structure has been deposited in the Protein Data Bank from a monoclinic and pseudo-merohedrally twinned crystal. Here, cocrystallization of ITPA with a molar ratio of XTP appears to have improved the crystals by eliminating twinning and resulted in an orthorhombic space group. However, there was no evidence for bound XTP in the structure. Comparison with substrate-bound NTPase from a thermophilic organism predicts the movement of residues within helix α1, the loop before α6 and helix α7 to cap off the active site when substrate is bound

  5. Catalyst support structure, catalyst including the structure, reactor including a catalyst, and methods of forming same

    Science.gov (United States)

    Van Norman, Staci A.; Aston, Victoria J.; Weimer, Alan W.

    2017-05-09

    Structures, catalysts, and reactors suitable for use for a variety of applications, including gas-to-liquid and coal-to-liquid processes and methods of forming the structures, catalysts, and reactors are disclosed. The catalyst material can be deposited onto an inner wall of a microtubular reactor and/or onto porous tungsten support structures using atomic layer deposition techniques.

  6. Nuclear reactor structural material forming less radioactive corrosion product

    International Nuclear Information System (INIS)

    Nakazawa, Hiroshi.

    1988-01-01

    Purpose: To provide nuclear reactor structural materials forming less radioactive corrosion products. Constitution: Ni-based alloys such as inconel alloy 718, 600 or inconel alloy 750 and 690 having excellent corrosion resistance and mechanical property even in coolants at high temperature and high pressure have generally been used as nuclear reactor structural materials. However, even such materials yield corrosion products being attacked by coolants circulating in the nuclear reactor, which produce by neutron irradiation radioactive corrosion products, that are deposited in primary circuit pipeways to constitute exposure sources. The present invention dissolves dissolves this problems by providing less activating nuclear reactor structural materials. That is, taking notice on the fact that Ni-58 contained generally by 68 % in Ni changes into Co-58 under irradiation of neutron thereby causing activation, the surface of nuclear reactor structural materials is applied with Ni plating by using Ni with a reduced content of Ni-58 isotopes. Accordingly, increase in the radiation level of the nuclear reactor structural materials can be inhibited. (K.M.)

  7. Microtunneling techniques to form an insitu barrier around existing structures

    International Nuclear Information System (INIS)

    Coller, P.J.; Abbott, D.G.

    1994-01-01

    The use of microtunneling techniques to construct underground structures has been available for many years. The technique, typically termed pipe roofing, is well proven and, to date, has been used principally to form underground access under existing structures where the use of cut and cover or conventional tunneling techniques was either impossible or too expensive. The first project involving the use of Iseki equipment, the first use of the pipe roofing technique as far as we are aware, was in 1971. This was followed by a number of projects in Japan, together with projects in Singapore and Hong Kong, totaling 12 projects. More recently, projects have been completed in Singapore and Japan and are currently in progress in Japan and Malaysia. This paper will briefly describe the use of the technique and the use of the new Iseki Unclemole for hard rock excavation to construct the largest pipe roof project ever undertaken in the world, together with other projects. The pipe roofing technique allows the construction of underground structures, in a variety of shapes and forms, by the use of remotely operated microtunnel machines. The paper will describe the potential application of this technique in the areas of hazardous and nuclear waste management

  8. Structuring free form verbal descriptions in equipment failure reports

    International Nuclear Information System (INIS)

    Huzdovich, J.

    1983-01-01

    Information is encoded for convenience in computer sort/search routines used to manage a large number of records. The codes in use for equipment failure reports are limited due to practical considerations, and this limitation forces the reporter to leave out information to satisfy the coding requirements. The free form verbal descriptions, as found in the Generating Availability Data System (GADS) and the Nuclear Plant Reliability Data System (NPRDS), allow for reporting of this non-codable information. A systematic approach to constructing the verbal description based on rules of grammar, especially syntax, results in a structured narrative suitable for computer data management schemes. In addition, the reporter has a full range of descriptive terminology and does not have to select subjectively from a predetermined, limited vocabulary to describe the event. This paper introduces a concept that places in perspective the integration of structured, formal reporting and free form verbal description. A second benefit of this structured narrative is the systematic development of failure mode/failure cause relationships in the event

  9. Nucleon Structure and Hyperon Form Factors from Lattice QCD.

    Energy Technology Data Exchange (ETDEWEB)

    Lin,H.W.

    2007-06-11

    In this work, I report the latest lattice QCD calculations of nucleon and hyperon structure from chiral fermions in 2+1-flavor dynamical simulations. All calculations are done with a chirally symmetric fermion action, domain-wall fermions, for valence quarks. I begin with the latest lattice results on the nucleon structure, focusing on results from RBC/UKQCD using 2+1-flavor chiral fermion actions. We find the chiral-extrapolated axial coupling constant at physical pion mass point. to be 1.23(5), consistent with experimental value. The renormalization constants for the structure functions are obtained from RI/MOM-scheme non-perturbative renormalization. We find first moments of the polarized and unpolarized nucleon structure functions at zero transfer momentum to be 0.133(13) and 0.203(23) respectively, using continuum chiral extrapolation. These are consistent with the experimental values, unlike previous calculations which have been 50% larger. We also have a prediction for the transversity, which we find to be 0.56(4). The twist-3 matrix element is consistent with zero which agrees with the prediction of the Wandzura-Wilczek relation. In the second half of this work, I report an indirect dynamical estimation of the strangeness proton magnetic moments using mixed actions. With the analysis of hyperon form factors and using charge symmetry, the strangeness of proton is found to be -0.066(2G), consistent with the Adelaide-JLab Collaboration's result. The hyperon {Sigma} and {Xi} axial coupling constants are also performed for the first time in a lattice calculation, g{sub {Sigma}{Sigma}} = 0.441(14) and g{sub {Xi}{Xi}} = -0.277(11).

  10. Nucleon Structure and hyperon form factors from lattice QCD

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Huey-Wen

    2007-06-11

    In this work, I report the latest lattice QCD calculations of nucleon and hyperon structure from chiral fermions in 2+1-flavor dynamical simulations. All calculations are done with a chirally symmetric fermion action, domain-wall fermions, for valence quarks. I begin with the latest lattice results on the nucleon structure, focusing on results from RBC/UKQCD using 2+1-flavor chiral fermion actions. We find the chiral-extrapolated axial coupling constant at physical pion mass point to be 1.23(5), consistant with experimental value. The renormalization constants for the structure functions are obtained from RI/MOM-scheme non-perturbative renormalization. We find first moments of the polarized and unpolarized nucleon structure functions at zero transfer momentum to be 0.133(13) and 0.203(23) respectively, using continuum chiral extrapolation. These are consistent with the experimental values, unlike previous calculations which have been 50% larger. We also have a prediction for the transversity, which we find to be 0.56(4). The twist-3 matrix element is consistent with zero which agrees with the prediction of the Wandzura-Wilczek relation. In the second half of this work, I report an indirect dynamical estimation of the strangeness proton magnetic moments using mixed actions. With the analysis of hyperon form factors and using charge symmetry, the strangeness of proton is found to be -0.066(26), consistent with the Adelaide-JLab Collaboration's result. The hyperon Sigma and Xi axial coupling constants are also performed for the first time in a lattice calculation, g_SigmaSigma = 0.441(14) and g_XiXi = -0.277(11).

  11. Structure of initial crystals formed during human amelogenesis

    Science.gov (United States)

    Cuisinier, F. J. G.; Voegel, J. C.; Yacaman, J.; Frank, R. M.

    1992-02-01

    X-ray diffraction analysis revealed only the existence of carbonated hydroxyapatite (c.HA) during amelogenesis, whereas conventional transmission electron microscopy investigations showed that developing enamel crystals have a ribbon-like habit. The described compositional changes could be an indication for the presence of minerals different from c.HA. However, the absence of identification of such a mineral shows the need of studies by high resolution electron microscopy (HREM) of initial formed human enamel crystals. We demonstrate the existence of two crystal families involved in the early stages of biomineralization: (a) nanometer-size particles which appeared as a precursor phase; (b) ribbon-like crystals, with a structure closely related to c.HA, which by a progressive thickening process tend to attain the mature enamel crystal habit.

  12. Cationic Phospholipids Forming Cubic Phases: Lipoplex Structure and Transfection Efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Koynova, Rumiana; Wang, Li; MacDonald, Robert C. (NWU)

    2008-10-29

    The transfection activity and the phase behavior of two novel cationic O-alkyl-phosphatidylcholines, 1,2-dioleoyl-sn-glycero-3-hexylphosphocholine (C6-DOPC) and 1,2-dierucoyl-sn-glycero-3-ethylphosphocholine (di22:1-EPC), have been examined with the aim of more completely understanding the mechanism of lipid-mediated DNA delivery. Both lipids form cubic phases: C6-DOPC in the entire temperature range from -10 to 90 C, while di22:1-EPC exhibits an irreversible lamellar-cubic transition between 50 and 70 C on heating. The lipoplexes formed by C6-DOPC arrange into hexagonal phase, while the lipoplexes of di22:1-EPC are lamellar. Both lipids exhibit lower transfection activity than the lamellar-forming 1,2-dioleoyl-sn-glycero-3-ethylphosphocholine (EDOPC). Thus, for the studied cationic phospholipid-DNA systems, the lipoplex phase state is a factor that does not seem to correlate with transfection activity. The parameter that exhibits better correlation with the transfection activity within the present data set is the phase state of the lipid dispersion prior to the addition of DNA. Thus, the lamellar lipid dispersion (EDOPC) produces more efficient lipoplexes than the dispersion with coexisting lamellar and cubic aggregates (diC22:1-EPC), which is even more efficient than the purely cubic dispersions (C6-DOPC; diC22:1-EPC after heating). It could be inferred from these data and from previous research that cubic phase lipid aggregates are unlikely to be beneficial to transfection. The lack of correlation between the phase state of lipoplexes and their transfection activity observed within the present data set does not mean that lipid phase state is generally unimportant for lipofection: a viewpoint now emerging from our previous studies is that the critical factor in lipid-mediated transfection is the structural evolution of lipoplexes within the cell, upon interacting and mixing with cellular lipids.

  13. Cationic phospholipids forming cubic phases: lipoplex structure and transfection efficiency.

    Science.gov (United States)

    Koynova, Rumiana; Wang, Li; Macdonald, Robert C

    2008-01-01

    The transfection activity and the phase behavior of two novel cationic O-alkyl-phosphatidylcholines, 1,2-dioleoyl- sn-glycero-3-hexylphosphocholine (C6-DOPC) and 1,2-dierucoyl- sn-glycero-3-ethylphosphocholine (di22:1-EPC), have been examined with the aim of more completely understanding the mechanism of lipid-mediated DNA delivery. Both lipids form cubic phases: C6-DOPC in the entire temperature range from -10 to 90 degrees C, while di22:1-EPC exhibits an irreversible lamellar-cubic transition between 50 and 70 degrees C on heating. The lipoplexes formed by C6-DOPC arrange into hexagonal phase, while the lipoplexes of di22:1-EPC are lamellar. Both lipids exhibit lower transfection activity than the lamellar-forming 1,2-dioleoyl- sn-glycero-3-ethylphosphocholine (EDOPC). Thus, for the studied cationic phospholipid-DNA systems, the lipoplex phase state is a factor that does not seem to correlate with transfection activity. The parameter that exhibits better correlation with the transfection activity within the present data set is the phase state of the lipid dispersion prior to the addition of DNA. Thus, the lamellar lipid dispersion (EDOPC) produces more efficient lipoplexes than the dispersion with coexisting lamellar and cubic aggregates (diC22:1-EPC), which is even more efficient than the purely cubic dispersions (C6-DOPC; diC22:1-EPC after heating). It could be inferred from these data and from previous research that cubic phase lipid aggregates are unlikely to be beneficial to transfection. The lack of correlation between the phase state of lipoplexes and their transfection activity observed within the present data set does not mean that lipid phase state is generally unimportant for lipofection: a viewpoint now emerging from our previous studies is that the critical factor in lipid-mediated transfection is the structural evolution of lipoplexes within the cell, upon interacting and mixing with cellular lipids.

  14. THE STRUCTURE OF THE STAR-FORMING CLUSTER RCW 38

    Energy Technology Data Exchange (ETDEWEB)

    Winston, E. [ESA-ESTEC (SRE-SA), Keplerlaan 1, 2201 AZ Noordwijk ZH (Netherlands); Wolk, S. J.; Bourke, T. L.; Spitzbart, B. [Harvard Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Megeath, S. T. [Ritter Observatory, Department of Physics and Astronomy, University of Toledo, 2801 West Bancroft Avenue, Toledo, OH 43606 (United States); Gutermuth, R., E-mail: ewinston@rssd.esa.int [Five Colleges Astronomy Department, Smith College, Northampton, MA 01027 (United States)

    2011-12-20

    We present a study of the structure of the high-mass star-forming region RCW 38 and the spatial distribution of its young stellar population. Spitzer Infrared Array Camera (IRAC) photometry (3-8 {mu}m) is combined with Two Micron All Sky Survey near-IR data to identify young stellar objects (YSOs) by IR-excess emission from their circumstellar material. Chandra X-ray data are used to identify class III pre-main-sequence stars lacking circumstellar material. We identify 624 YSOs: 23 class 0/I and 90 flat spectrum protostars, 437 class II stars, and 74 class III stars. We also identify 29 (27 new) O star candidates over the IRAC field. Seventy-two stars exhibit IR-variability, including 7 class 0/I and 12 flat spectrum YSOs. A further 177 tentative candidates are identified by their location in the IRAC [3.6] versus [3.6]-[5.8] color-magnitude diagram. We find strong evidence of subclustering in the region. Three subclusters were identified surrounding the central cluster, with massive and variable stars in each subcluster. The central region shows evidence of distinct spatial distributions of the protostars and pre-main-sequence stars. A previously detected IR cluster, DB2001{sub O}bj36, has been established as a subcluster of RCW 38. This suggests that star formation in RCW 38 occurs over a more extended area than previously thought. The gas-to-dust ratio is examined using the X-ray derived hydrogen column density, N{sub H} and the K-band extinction, and found to be consistent with the diffuse interstellar medium, in contrast with Serpens and NGC 1333. We posit that the high photoionizing flux of massive stars in RCW 38 affects the agglomeration of the dust grains.

  15. Integrable couplings of relativistic Toda lattice systems in polynomial form and rational form, their hierarchies and bi-Hamiltonian structures

    Energy Technology Data Exchange (ETDEWEB)

    Xu Xixiang [College of Science, Shandong University of Science and Technology, Qingdao 266510 (China)], E-mail: xixiang_xu@yahoo.com.cn

    2009-10-02

    Integrable couplings of relativistic Toda lattice systems in polynomial form and rational form, and their hierarchies, are derived from a four-by-four discrete matrix eigenvalue problem. The bi-Hamiltonian structure for every integrable coupling in the two hierarchies obtained is established by means of the discrete variational identity. Ultimately, Liouvolle integrability of the obtained integrable couplings is demonstrated.

  16. Structure and applications of point form relativistic quantum mechanics

    International Nuclear Information System (INIS)

    Klink, W.H.

    2003-01-01

    The framework of point form relativistic quantum mechanics is used to construct mass and current operators for hadronic systems with finite degree of freedom. For the point form all of the interactions are in the four-momentum operator and, since Lorentz transformations are kinematic, the theory is manifestly covariant. In the Bakamjian-Thomas version of the point form the four-momentum operator is written as a product of the four-velocity operator and mass operator, where the mass operator is the sum of free and interacting mass operators. Interacting mass operators can be constructed from vertices, matrix elements of local field operators evaluated at the space-time point zero, where the states are eigenstates of the four-velocity. Applications include the study of the spectra and widths of vector mesons, viewed as bound states of quark-antiquark pairs. Besides mass operators, current operators are needed to compute form factors. Form factors are matrix elements of current operators on mass operator eigenstates and are often calculated with one-body current operators (in the point form this is called the point form spectator approximation); but in a properly relativistic theory there must also be many-body current operators. Minimal currents needed to satisfy current conservation in the presence of hadronic interactions (called dynamically determined currents) are shown to be easily calculated in the point form. (author)

  17. EXPLOSIVE FORMING – ECONOMICAL TECHNOLOGY FOR AEROSPACE STRUCTURES

    Directory of Open Access Journals (Sweden)

    Niculae MARIN

    2010-12-01

    Full Text Available The explosive forming represents a technological alternative for obtaining small-lot parts,with inexpensive and efficient manufacturing preparation. The explosive forming processing methodspresent a series of important advantages, being recommended for the wide-scale application in theaerospace industry. The economic benefit varies from case to case, independent from the part type,manufacturing series and user.

  18. EXPLOSIVE FORMING – ECONOMICAL TECHNOLOGY FOR AEROSPACE STRUCTURES

    OpenAIRE

    Niculae MARIN; Victor GHIZDAVU

    2010-01-01

    The explosive forming represents a technological alternative for obtaining small-lot parts,with inexpensive and efficient manufacturing preparation. The explosive forming processing methodspresent a series of important advantages, being recommended for the wide-scale application in theaerospace industry. The economic benefit varies from case to case, independent from the part type,manufacturing series and user.

  19. Hospital board structure: changing form and changing issues.

    Science.gov (United States)

    Tregoning, S

    2000-01-01

    Economic and social pressures are compelling many hospitals to consider their current board structure in an effort to position their hospital to meet changing demands. A national profile of the structures of hospital boards has been compiled from a questionnaire completed by hospital board representatives from both government and non-government sectors. Results show that hospital board structures are a hybrid of both philanthropic and corporate models. New structures may be required to meet future challenges. In developing new structures, consideration should be given to identifying the skills and processes required to undertake board business.

  20. Spatial and kinematic structure of Monoceros star-forming region

    Science.gov (United States)

    Costado, M. T.; Alfaro, E. J.

    2018-05-01

    The principal aim of this work is to study the velocity field in the Monoceros star-forming region using the radial velocity data available in the literature, as well as astrometric data from the Gaia first release. This region is a large star-forming complex formed by two associations named Monoceros OB1 and OB2. We have collected radial velocity data for more than 400 stars in the area of 8 × 12 deg2 and distance for more than 200 objects. We apply a clustering analysis in the subspace of the phase space formed by angular coordinates and radial velocity or distance data using the Spectrum of Kinematic Grouping methodology. We found four and three spatial groupings in radial velocity and distance variables, respectively, corresponding to the Local arm, the central clusters forming the associations and the Perseus arm, respectively.

  1. Effect of temperature on crack initiation in gas formed structures

    Energy Technology Data Exchange (ETDEWEB)

    Gohari, S.; Vrcelj, Z.; Sharifi, S.; Sharifishourabi, G.; Abadi, R. [Universiti Teknlogi Malaysia, Skudai (Malaysia)

    2013-12-15

    In the gas forming process, the work piece is formed by applying gas pressure. However, the gas pressure and the accompanying gas temperature can result in crack initiation and unstable crack growth. Thus, it is vital to determine the critical values of applied gas pressure and temperature to avoid crack and fracture failure. We studied the mechanism of fracture using an experimental approach and finite element simulations of a perfect aluminum sheet containing no inclusions and voids. The definition of crack was based on ductile damage mechanics. For inspection of initiation of crack and rupture in gas-metal forming, the ABAQUS/EXPLICIT simulation was used. In gas forming, the applied load is the pressure applied rather than the punching force. The results obtained from both the experimental approach and finite element simulations were compared. The effects of various parameters, such as temperature and gas pressure value on crack initiation, were taken into account.

  2. Crystal structure of inactive form of Rab3B

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Wei [Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Science, Huazhong Normal University, Wuhan 430079 (China); Shen, Yang [Structural Genomics Consortium, University of Toronto, 101 College St., Toronto, Ontario, Canada M5G 1L7 (Canada); Jiao, Ronghong [Department of Function Inspection, Hebei Provincial People' s Hospital, Shijiazhuang 050051 (China); Liu, Yanli; Deng, Lingfu [Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Science, Huazhong Normal University, Wuhan 430079 (China); Qi, Chao, E-mail: qichao@mail.ccnu.edu.cn [Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Science, Huazhong Normal University, Wuhan 430079 (China)

    2012-02-24

    Highlights: Black-Right-Pointing-Pointer This is the first structural information of human Rab3B. Black-Right-Pointing-Pointer To provides a structural basis for the GDP/GTP switch in controlling the activity of Rab3. Black-Right-Pointing-Pointer The charge distribution of Rab3B indicates its unique roles in vesicular trafficking. -- Abstract: Rab proteins are the largest family of ras-related GTPases in eukaryotic cells. They act as directional molecular switches at membrane trafficking, including vesicle budding, cargo sorting, transport, tethering, and fusion. Here, we generated and crystallized the Rab3B:GDP complex. The structure of the complex was solved to 1.9 A resolution and the structural base comparison with other Rab3 members provides a structural basis for the GDP/GTP switch in controlling the activity of small GTPase. The comparison of charge distribution among the members of Rab3 also indicates their different roles in vesicular trafficking.

  3. Crystal structure of inactive form of Rab3B

    International Nuclear Information System (INIS)

    Zhang, Wei; Shen, Yang; Jiao, Ronghong; Liu, Yanli; Deng, Lingfu; Qi, Chao

    2012-01-01

    Highlights: ► This is the first structural information of human Rab3B. ► To provides a structural basis for the GDP/GTP switch in controlling the activity of Rab3. ► The charge distribution of Rab3B indicates its unique roles in vesicular trafficking. -- Abstract: Rab proteins are the largest family of ras-related GTPases in eukaryotic cells. They act as directional molecular switches at membrane trafficking, including vesicle budding, cargo sorting, transport, tethering, and fusion. Here, we generated and crystallized the Rab3B:GDP complex. The structure of the complex was solved to 1.9 Å resolution and the structural base comparison with other Rab3 members provides a structural basis for the GDP/GTP switch in controlling the activity of small GTPase. The comparison of charge distribution among the members of Rab3 also indicates their different roles in vesicular trafficking.

  4. Nucleon quark structure and strong meson-nucleon form factors

    International Nuclear Information System (INIS)

    Efimov, G.V.; Ivanov, M.A.

    1987-01-01

    The nucleon is considered as a three-quark system in virton-quark model. The main statistic properties of proton and neutron are calculated: magnetic moments, electromagnetic radii, G A /G V ratio in weak neutron decay. Strong meson-nucleon form factors which determine nucleon-nucleon potential are obtained as a function of squared transfer momentum of mesons. The results are compared with phenomenological form factors used for description of phases of NN-scattering in the one-boson-, exchange model

  5. Ectoparasites and endoparasites of fish form networks with different structures.

    Science.gov (United States)

    Bellay, S; DE Oliveira, E F; Almeida-Neto, M; Mello, M A R; Takemoto, R M; Luque, J L

    2015-06-01

    Hosts and parasites interact with each other in a variety of ways, and this diversity of interactions is reflected in the networks they form. To test for differences in interaction patterns of ecto- and endoparasites we analysed subnetworks formed by each kind of parasites and their host fish species in fish-parasite networks for 22 localities. We assessed the proportion of parasite species per host species, the relationship between parasite fauna composition and host taxonomy, connectance, nestedness and modularity of each subnetwork (n = 44). Furthermore, we evaluated the similarity in host species composition among modules in ecto- and endoparasite subnetworks. We found several differences between subnetworks of fish ecto- and endoparasites. The association with a higher number of host species observed among endoparasites resulted in higher connectance and nestedness, and lower values of modularity in their subnetworks than in those of ectoparasites. Taxonomically related host species tended to share ecto- or endoparasites with the same interaction intensity, but the species composition of hosts tended to differ between modules formed by ecto- and endoparasites. Our results suggest that different evolutionary and ecological processes are responsible for organizing the networks formed by ecto- and endoparasites and fish.

  6. THE STRUCTURAL EVOLUTION OF FORMING AND EARLY STAGE STAR CLUSTERS

    International Nuclear Information System (INIS)

    Jaehnig, Karl O.; Da Rio, Nicola; Tan, Jonathan C.

    2015-01-01

    We study the degree of angular substructure in the stellar position distribution of young members of Galactic star-forming regions, looking for correlations with distance from cluster center, surface number density of stars, and local dynamical age. To this end we adopt the catalog of members in 18 young (∼1-3 Myr) clusters from the Massive Young Star-Forming Complex Study in Infrared and X-ray Survey and the statistical analysis of the angular dispersion parameter, δ ADP, N . We find statistically significant correlation between δ ADP, N and physical projected distance from the center of the clusters, with the centers appearing smoother than the outskirts, consistent with more rapid dynamical processing on local dynamical, free-fall or orbital timescales. Similarly, smoother distributions are seen in regions of higher surface density, or older dynamical ages. These results indicate that dynamical processing that erases substructure is already well-advanced in young, sometimes still-forming, clusters. Such observations of the dissipation of substructure have the potential to constrain theoretical models of the dynamical evolution of young and forming clusters

  7. Efficient Design And Fabrication Of Free-Form Reciprocal Structures

    DEFF Research Database (Denmark)

    Parigi, Dario; Kirkegaard, Poul Henning

    2013-01-01

    Structures based on the principle of reciprocity have been autonomously studied and used since the antiquity on the basis of different needs and purposes. The application of the principle of reciprocity requires the presence of at least two elements, at the same time both supporting and being sup...

  8. Putting Encyclopaedia Knowledge into Structural Form: Finite State Transducers Approach

    Directory of Open Access Journals (Sweden)

    Pajić Vesna

    2011-06-01

    Full Text Available In biology and functional genomics in particular, understanding the dependence and interplay between different genome and ecological characteristics of organisms is a very challenging problem. There are some public databases which combine this kind of information, but there is still much more information about microbes and other organisms that reside in unstructured and semi-structured documents, such as encyclopaedias. In this paper we present a method for extracting information from semi-structured resources, such as encyclopaedias, based on finite state transducers, consisting of two clearly distinguished phases. The first phase strongly relies on the analysis of the document structure and it is used for locating records of data in the text. The second phase is based on the finite state transducers created for extracting the data, which can be modified so as to achieve the preferred efficiency and it is used for extracting the particular characteristic from the text. We show how the two phase method is applied to the text of the encyclopaedia “Systematic Bacteriology”. A fully structured database with genotype and phenotype characteristics of organisms has been created from the encyclopaedia unstructured descriptions.

  9. Crystallization and Characterization of Galdieria sulphuraria RUBISCO in Two Crystal Forms: Structural Phase Transition Observed in P21 Crystal Form

    Directory of Open Access Journals (Sweden)

    Boguslaw Stec

    2007-10-01

    Full Text Available We have isolated ribulose-1,5-bisphosphate-carboxylase/oxygenase (RUBISCOfrom the red algae Galdieria Sulphuraria. The protein crystallized in two different crystalforms, the I422 crystal form being obtained from high salt and the P21 crystal form beingobtained from lower concentration of salt and PEG. We report here the crystallization,preliminary stages of structure determination and the detection of the structural phasetransition in the P21 crystal form of G. sulphuraria RUBISCO. This red algae enzymebelongs to the hexadecameric class (L8S8 with an approximate molecular weight 0.6MDa.The phase transition in G. sulphuraria RUBISCO leads from two hexadecamers to a singlehexadecamer per asymmetric unit. The preservation of diffraction power in a phasetransition for such a large macromolecule is rare.

  10. Electronic structures of interfacial states formed at polymeric semiconductor heterojunctions

    Science.gov (United States)

    Huang, Ya-Shih; Westenhoff, Sebastian; Avilov, Igor; Sreearunothai, Paiboon; Hodgkiss, Justin M.; Deleener, Caroline; Friend, Richard H.; Beljonne, David

    2008-06-01

    Heterojunctions between organic semiconductors are central to the operation of light-emitting and photovoltaic diodes, providing respectively for electron-hole capture and separation. However, relatively little is known about the character of electronic excitations stable at the heterojunction. We have developed molecular models to study such interfacial excited electronic excitations that form at the heterojunction between model polymer donor and polymer acceptor systems: poly(9,9-dioctylfluorene-co-bis-N,N-(4-butylphenyl)-bis-N,N-phenyl-1,4-phenylenediamine) (PFB) with poly(9,9-dioctylfluorene-co-benzothiadiazole) (F8BT), and poly(9,9-dioctylfluorene-co-N-(4-butylphenyl)diphenylamine) (TFB) with F8BT. We find that for stable ground-state geometries the excited state has a strong charge-transfer character. Furthermore, when partly covalent, modelled radiative lifetimes (~10-7s) and off-chain axis polarization (30∘) match observed `exciplex' emission. Additionally for the PFB:F8BT blend, geometries with fully ionic character are also found, thus accounting for the low electroluminescence efficiency of this system.

  11. Anisotropy of magnetoviscous effect in structure-forming ferrofluids

    Science.gov (United States)

    Sreekumari, Aparna; Ilg, Patrick

    2015-07-01

    The magnetoviscous effect, change in viscosity with change in magnetic field strength, and the anisotropy of the magnetoviscous effect, change in viscosity with orientation of magnetic field, have been a focus of interest for four decades. A satisfactory understanding of the microscopic origin of anisotropy of the magnetoviscous effect in magnetic fluids is still a matter of debate and a field of intense research. Here, we present an extensive simulation study to understand the relation between the anisotropy of the magnetoviscous effect and the underlying change in microstructures of ferrofluids. Our results indicate that field-induced chainlike structures respond very differently depending on their orientation relative to the direction of an externally applied shear flow, which leads to a pronounced anisotropy of viscosity. In this work, we focus on three exemplary values of dipolar interaction strengths which correspond to weak, intermediate, and strong interactions between dipolar colloidal particles. We compare our simulation results with an experimental study on cobalt-based ferrofluids as well as with an existing theoretical model called the chain model. A nonmonotonic behavior in the anisotropy of the magnetoviscous effect is observed with increasing dipolar interaction strength and is explained in terms of microstructure formation.

  12. Tensioned Fabric Structures with Surface in the Form of Chen-Gackstatter

    Directory of Open Access Journals (Sweden)

    Yee Hooi Min

    2016-01-01

    Full Text Available Form-finding has to be carried out for tensioned fabric structure in order to determine the initial equilibrium shape under prescribed support condition and prestress pattern. Tensioned fabric structures are normally designed to be in the form of equal tensioned surface. Tensioned fabric structure is highly suited to be used for realizing surfaces of complex or new forms. However, research study on a new form as a tensioned fabric structure has not attracted much attention. Another source of inspiration minimal surface which could be adopted as form for tensioned fabric structure is very crucial. The aim of this study is to propose initial equilibrium shape of tensioned fabric structures in the form of Chen-Gackstatter. Computational form-finding using nonlinear analysis method is used to determine the Chen-Gackstatter form of uniformly stressed surfaces. A tensioned fabric structure must curve equally in opposite directions to give the resulting surface a three dimensional stability. In an anticlastic doubly curved surface, the sum of all positive and all negative curvatures is zero. This study provides an alternative choice for structural designer to consider the Chen-Gackstatter applied in tensioned fabric structures. The results on factors affecting initial equilibrium shape can serve as a reference for proper selection of surface parameter for achieving a structurally viable surface.

  13. Extracting energy and structure properties of glass-forming liquids from structural relaxation time.

    Science.gov (United States)

    Wang, Lianwen

    2012-04-18

    A comprehensive examination of the kinetic liquid model (Wang et al 2010 J. Phys.: Condens. Matter 22 455104) is carried out by fitting the structural relaxation time of 26 different glass-forming liquids in a wide temperature range, including most of the well-studied materials. Careful analysis of the compiled reported data reveals that experimental inaccuracies should not be overlooked in any 'benchmark test' of relating theories or models (e.g. in Lunkenheimer et al 2010 Phys. Rev. E 81 051504). The procedure, accuracy, ability, and efficiency of the kinetic liquid model are discussed in detail and in comparison with other available fitting methods. In general, the kinetic liquid model could be verified by 17 of the 26 compiled data sets and can serve as a meaningful approximative method for analyzing these liquids. Nonetheless, further experimental examinations in a wide temperature range are needed and are called for. Through fitting, the microscopic details of these liquids are extracted, namely, the enthalpy, entropy, and cooperativity in structural relaxation, which may facilitate further quantitative analysis to both the liquidus and glassy states of these materials.

  14. Polymorphism in phenobarbital: discovery of a new polymorph and crystal structure of elusive form V.

    Science.gov (United States)

    Roy, Saikat; Goud, N Rajesh; Matzger, Adam J

    2016-03-21

    This report highlights the discovery of a new polymorph of the anticonvulsant drug phenobarbital (PB) using polymer-induced heteronucleation (PIHn) and unravelling the crystal structure of the elusive form V. Both forms are characterized by structural, thermal and VT-Raman spectroscopy methods to elucidate phase transformation behavior and shed light on stability relationships.

  15. I-motif DNA structures are formed in the nuclei of human cells

    Science.gov (United States)

    Zeraati, Mahdi; Langley, David B.; Schofield, Peter; Moye, Aaron L.; Rouet, Romain; Hughes, William E.; Bryan, Tracy M.; Dinger, Marcel E.; Christ, Daniel

    2018-06-01

    Human genome function is underpinned by the primary storage of genetic information in canonical B-form DNA, with a second layer of DNA structure providing regulatory control. I-motif structures are thought to form in cytosine-rich regions of the genome and to have regulatory functions; however, in vivo evidence for the existence of such structures has so far remained elusive. Here we report the generation and characterization of an antibody fragment (iMab) that recognizes i-motif structures with high selectivity and affinity, enabling the detection of i-motifs in the nuclei of human cells. We demonstrate that the in vivo formation of such structures is cell-cycle and pH dependent. Furthermore, we provide evidence that i-motif structures are formed in regulatory regions of the human genome, including promoters and telomeric regions. Our results support the notion that i-motif structures provide key regulatory roles in the genome.

  16. Raman spectroscopy used for structural investigations of anodically formed ZrO2

    International Nuclear Information System (INIS)

    Koneska, Zagorka; Arsova, Irena

    2003-01-01

    The structure of the oxide formed on Zr(99% + Hf) with anodic oxidation at different potentials in 1 mol/dm 3 H 3 PO 4 and 2 mol/dm 3 KOH solutions were investigated using Raman spectroscopy. Normally the anodic oxides of Zr form only crystals. Under certain circumstances, amorphous anodic ZrO 2 can be observed. Amorphous phase is observed for the anodically formed zirconium oxides in H 3 PO 4 . The oxide formed in KOH at potential of 80 V, where sparks appears on the Zr electrode showed crystalline structure. (Original)

  17. Process for forming exoergic structures with the use of a plasma

    Science.gov (United States)

    Kelly, M.D.

    1987-05-29

    A method of forming exoergic structures, as well as exoergic structures produced by the method, is provided. The method comprises the steps of passing a plasma-forming gas through a plasma spray gun, forming a plasma spray, introducing exoergic material into the plasma spray and directing the plasma spray toward a substrate, and allowing the exoergic material to become molten in the plasma spray and to thereafter impinge on the substrate to form a solid mass of exoergic material, the shape of which corresponds to the shape of the substrate.

  18. Relating structural parameters to leachability in a glass-bonded ceramic waste form

    International Nuclear Information System (INIS)

    Frank, S. M.; Johnson, S. G.; Moschetti, T. L.

    1998-01-01

    Lattice parameters for a crystalline material can be obtained by several methods, notably by analyzing x-ray powder diffraction patterns. By utilizing a computer program to fit a pattern, one can follow the evolution or subtle changes in a structure of a crystalline species in different environments. This work involves such a study for an essential component of the ceramic waste form that is under development at Argonne National Laboratory. Zeolite 4A and zeolite 5A are used to produce two different types of waste forms: a glass-bonded sodalite and a glass-bonded zeolite, respectively. Changes in structure during production of the waste forms are discussed. Specific salt-loadings in the sodalite waste form are related to relative peak intensities of certain reflections in the XRD patterns. Structural parameters for the final waste forms will also be given and related to leachability under standard conditions

  19. Sediment concentration and bed form structures of Gulf of Cambay from remote sensing

    Digital Repository Service at National Institute of Oceanography (India)

    Kunte, P.D.

    period, the bottom currents pull sediment (sand) particles supplied by major and minor rivers, rolling along the Gulf bed. These sediments perhaps participate in the formation of bed form structures. The topography of the Gulf bottom comprises of numerous...

  20. Low resolution solution structure of the Apo form of Escherichia coli haemoglobin protease Hbp.

    NARCIS (Netherlands)

    scott, D.J.; Grossman, J.G.; Tame, J.R.H.; Byron, O.; Wilson, K.S.; Otto, B.R.

    2002-01-01

    We have studied the solution properties of the apo form of the haemoglobin protease or "haemoglobinase", Hbp, a principal component of an important iron acquisition system in pathogenic Escherichia coli. Experimental determination of secondary structure content from circular dichroism (CD)

  1. A Biomimetic Structural Form: Developing a Paradigm to Attain Vital Sustainability in Tall Architecture

    OpenAIRE

    Osama Al-Sehail

    2017-01-01

    This paper argues for sustainability as a necessity in the evolution of tall architecture. It provides a different mode for dealing with sustainability in tall architecture, taking into consideration the speciality of its typology. To this end, the article develops a Biomimetic Structural Form as a paradigm to attain Vital Sustainability. A Biomimetic Structural Form, which is derived from the amalgamation of biomimicry as an approach for sustainability defining nature as source of knowledge ...

  2. Excitations of the isobaric analog states T=0, 1, 2 and 2 in isobars 60Zn (Tz=0), 60Cu (Tz=1) and 60Ni (Tz=2) by the two-nucleon (2p, pn, 2n) stripping transfer reactions of 16O ions on 58Ni nuclei

    International Nuclear Information System (INIS)

    Okuma, Yasuhiko

    1992-01-01

    The isobaric analog states (IAS's) T=0, 1, 2 and 2 in isobars 60 Zn (Tz=0), 60 Cu (Tz=1) and 60 Ni (Tz=2) were studied by the three types of two-nucleon (2p, pn, 2n) stripping transfer reactions induced by the same beams 16 O and targets 58 Ni at an incident energy 80 MeV. The excitation energies of observed IAS's are in good fits with those calculated theoretically. The g'nd state 2 + , T=1 in 60 Cu may not be populated vy the ( 16 O, 14 N) reaction. The mutual excitation ( 16 O, 14 N * ) may be considered in the present population in 50 Cu. The isospin aspects of these reactions are quite prominent. All angular distributions of these IAS's have a forward peaked shape. Those of the O + states show a strongly oscillated pattern. Those of the 2 + states have no evidences of the clear oscillations. The similarities are observed between the angular distributions of IAS's. The EFR-DWBA calculations, in which the direct one-step cluster transferrs of two nucleons are assumed, reproduce reasonably the data points. The similarities between the heavy and the light ion induced two-nucleon stripping transfer reactions appear in both the reaction mechanisms and the spectroscopies of residual nuclei. The excitations of these IAS's will be an appearances of the single particle properties of transferred two-nucleons. (author)

  3. Structural studies of disordered Mg2NiH4 formed by mechanical grinding

    DEFF Research Database (Denmark)

    Rönnebro, Ewa; Jensen, Jens Oluf; Noréus, Dag

    1999-01-01

    The low temperature phase of Mg2NiH4 was mechanically ground in argon atmosphere. The ordered monoclinic structure was destroyed to form the disordered cubic structure, previously only found above 510 K. With a Guinier-Hagg X-ray camera the cell parameter was determined to be a=6.492(3) Angstrom....

  4. Structural and reduced-form modeling and forecasting with application to Armenia

    NARCIS (Netherlands)

    Poghosyan, K.

    2012-01-01

    The thesis deals with structural and reduced-form modeling and forecasting of key macroeconomic variables (real growth of GDP, inflation, exchange rate, and policy interest rate). The central part of the thesis (Chapters 2-4) consists of three chapters. Chapter 2 considers the structural DSGE model

  5. Linking structure to fragility in bulk metallic glass-forming liquids

    International Nuclear Information System (INIS)

    Wei, Shuai; Stolpe, Moritz; Gross, Oliver; Gallino, Isabella; Hembree, William; Busch, Ralf; Evenson, Zach; Bednarcik, Jozef; Kruzic, Jamie J.

    2015-01-01

    Using in-situ synchrotron X-ray scattering, we show that the structural evolution of various bulk metallic glass-forming liquids can be quantitatively connected to their viscosity behavior in the supercooled liquid near T g . The structural signature of fragility is identified as the temperature dependence of local dilatation on distinct key atomic length scales. A more fragile behavior results from a more pronounced thermally induced dilatation of the structure on a length scale of about 3 to 4 atomic diameters, coupled with shallower temperature dependence of structural changes in the nearest neighbor environment. These findings shed light on the structural origin of viscous slowdown during undercooling of bulk metallic glass-forming liquids and demonstrate the promise of predicting the properties of bulk metallic glasses from the atomic scale structure

  6. Linking structure to fragility in bulk metallic glass-forming liquids

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Shuai, E-mail: shuai.wei@asu.edu, E-mail: m.stolpe@mx.uni-saarland.de [Department of Materials Science and Engineering, Saarland University, Campus C63, 66123 Saarbrücken (Germany); Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287 (United States); Stolpe, Moritz, E-mail: shuai.wei@asu.edu, E-mail: m.stolpe@mx.uni-saarland.de; Gross, Oliver; Gallino, Isabella; Hembree, William; Busch, Ralf [Department of Materials Science and Engineering, Saarland University, Campus C63, 66123 Saarbrücken (Germany); Evenson, Zach [Department of Materials Science and Engineering, Saarland University, Campus C63, 66123 Saarbrücken (Germany); Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft- und Raumfahrt (DLR), 51170 Köln (Germany); Bednarcik, Jozef [Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, D-22603 Hamburg (Germany); Kruzic, Jamie J. [Material Science, School of Mechanical, Industrial, and Manufacturing Engineering, Oregon State University, Corvallis, Oregon 97331 (United States)

    2015-05-04

    Using in-situ synchrotron X-ray scattering, we show that the structural evolution of various bulk metallic glass-forming liquids can be quantitatively connected to their viscosity behavior in the supercooled liquid near T{sub g}. The structural signature of fragility is identified as the temperature dependence of local dilatation on distinct key atomic length scales. A more fragile behavior results from a more pronounced thermally induced dilatation of the structure on a length scale of about 3 to 4 atomic diameters, coupled with shallower temperature dependence of structural changes in the nearest neighbor environment. These findings shed light on the structural origin of viscous slowdown during undercooling of bulk metallic glass-forming liquids and demonstrate the promise of predicting the properties of bulk metallic glasses from the atomic scale structure.

  7. Features of ultrafine-grained structure forming in Zr-1Nb alloy

    Energy Technology Data Exchange (ETDEWEB)

    Stepanova, Ekaterina N.; Prosolov, Konstantin A. [National Research Tomsk Polytechnic University, Tomsk (Russian Federation); Grabovetskaya, Galina P.; Mishin, Ivan P. [Institute of Strength Physics and Materials Science of Siberian Branch of Russian Academy of Sciences, Tomsk (Russian Federation)

    2013-07-01

    Ultrafine-grained structure forming by the method combined reversible hydrogenation and hot pressing in Zr-1Nb alloy was investigated. Preliminary hydrogenation to concentrations of (0.14–0.4) % at 873 K is found to lead to yield strength decreasing in Zr-1Nb alloy during hot pressing by 1,5–2 times. During uniaxial compression at (70–72) % under isothermal conditions at a temperature of 873 K in Zr-1Nb alloy, hydrogenated to concentration of 0.22 %, homogeneous ultrafine grained structure with an average grain size of 0,4 P m was formed. Key words: zirconium alloy, ultrafine-grained structure, hydrogen.

  8. Methods of generalizing and classifying layer structures of a special form

    Energy Technology Data Exchange (ETDEWEB)

    Viktorova, N P

    1981-09-01

    An examination is made of the problem of classifying structures represented by weighted multilayer graphs of special form with connections between the vertices of each layer. The classification of structures of such a form is based on the construction of resolving sets of graphs as a result of generalization of the elements of the training sample of each class and the testing of whether an input object is isomorphic (with allowance for the weights) to the structures of the resolving set or not. 4 references.

  9. Quantitative characterization of the atomic-scale structure of oxyhydroxides in rusts formed on steel surfaces

    International Nuclear Information System (INIS)

    Saito, M.; Suzuki, S.; Kimura, M.; Suzuki, T.; Kihira, H.; Waseda, Y.

    2005-01-01

    Quantitative X-ray structural analysis coupled with anomalous X-ray scattering has been used for characterizing the atomic-scale structure of rust formed on steel surfaces. Samples were prepared from rust layers formed on the surfaces of two commercial steels. X-ray scattered intensity profiles of the two samples showed that the rusts consisted mainly of two types of ferric oxyhydroxide, α-FeOOH and γ-FeOOH. The amounts of these rust components and the realistic atomic arrangements in the components were estimated by fitting both the ordinary and the environmental interference functions with a model structure calculated using the reverse Monte Carlo simulation technique. The two rust components were found to be the network structure formed by FeO 6 octahedral units, the network structure itself deviating from the ideal case. The present results also suggest that the structural analysis method using anomalous X-ray scattering and the reverse Monte Carlo technique is very successful in determining the atomic-scale structure of rusts formed on the steel surfaces

  10. An ontology-driven tool for structured data acquisition using Web forms.

    Science.gov (United States)

    Gonçalves, Rafael S; Tu, Samson W; Nyulas, Csongor I; Tierney, Michael J; Musen, Mark A

    2017-08-01

    Structured data acquisition is a common task that is widely performed in biomedicine. However, current solutions for this task are far from providing a means to structure data in such a way that it can be automatically employed in decision making (e.g., in our example application domain of clinical functional assessment, for determining eligibility for disability benefits) based on conclusions derived from acquired data (e.g., assessment of impaired motor function). To use data in these settings, we need it structured in a way that can be exploited by automated reasoning systems, for instance, in the Web Ontology Language (OWL); the de facto ontology language for the Web. We tackle the problem of generating Web-based assessment forms from OWL ontologies, and aggregating input gathered through these forms as an ontology of "semantically-enriched" form data that can be queried using an RDF query language, such as SPARQL. We developed an ontology-based structured data acquisition system, which we present through its specific application to the clinical functional assessment domain. We found that data gathered through our system is highly amenable to automatic analysis using queries. We demonstrated how ontologies can be used to help structuring Web-based forms and to semantically enrich the data elements of the acquired structured data. The ontologies associated with the enriched data elements enable automated inferences and provide a rich vocabulary for performing queries.

  11. 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.

  12. Method for fabricating five-level microelectromechanical structures and microelectromechanical transmission formed

    Science.gov (United States)

    Rodgers, M. Steven; Sniegowski, Jeffry J.; Miller, Samuel L.; McWhorter, Paul J.

    2000-01-01

    A process for forming complex microelectromechanical (MEM) devices having five layers or levels of polysilicon, including four structural polysilicon layers wherein mechanical elements can be formed, and an underlying polysilicon layer forming a voltage reference plane. A particular type of MEM device that can be formed with the five-level polysilicon process is a MEM transmission for controlling or interlocking mechanical power transfer between an electrostatic motor and a self-assembling structure (e.g. a hinged pop-up mirror for use with an incident laser beam). The MEM transmission is based on an incomplete gear train and a bridging set of gears that can be moved into place to complete the gear train to enable power transfer. The MEM transmission has particular applications as a safety component for surety, and for this purpose can incorporate a pin-in-maze discriminator responsive to a coded input signal.

  13. Method for fabricating five-level microelectromechanical structures and microelectromechanical transmission formed

    Energy Technology Data Exchange (ETDEWEB)

    Rodgers, M.S.; Sniegowski, J.J.; Miller, S.L.; McWhorter, P.J.

    2000-07-04

    A process is disclosed for forming complex microelectromechanical (MEM) devices having five layers or levels of polysilicon, including four structural polysilicon layers wherein mechanical elements can be formed, and an underlying polysilicon layer forming a voltage reference plane. A particular type of MEM device that can be formed with the five-level polysilicon process is a MEM transmission for controlling or interlocking mechanical power transfer between an electrostatic motor and a self-assembling structure (e.g. a hinged pop-up mirror for use with an incident laser beam). The MEM transmission is based on an incomplete gear train and a bridging set of gears that can be moved into place to complete the gear train to enable power transfer. The MEM transmission has particular applications as a safety component for surety, and for this purpose can incorporate a pin-in-maze discriminator responsive to a coded input signal.

  14. Experiences of Social and Structural Forms of Stigma Among Chinese Immigrant Consumers with Psychosis.

    Science.gov (United States)

    Cheng, Zhen Hadassah; Tu, Ming-Che; Li, Vanessa A; Chang, Rachel W; Yang, Lawrence Hsin

    2015-12-01

    Chinese immigrants tend to rely on family and close community for support given their vulnerable societal position. Yet stigma, especially from structural and familial sources, may have a particularly harmful impact upon Chinese immigrants with psychosis. Using a descriptive analysis based upon grounded theory, we examined stigma experiences of 50 Chinese immigrant consumers with psychosis, paying particular attention to frequency, sources, and themes of social and structural stigma. Although past research indicates that family is a recipient of stigma, we found instead that family members were common perpetuators of social forms of stigma. We also found that perceptions of work deficit underlie many forms of stigma, suggesting this is "what matters most" in this community. Lack of financial resources and language barriers comprised most frequent forms of structural stigma. Anti-stigma efforts should aim to improve consumer's actual and perceived employability to target what is most meaningful in Chinese immigrant communities.

  15. Turbine airfoil with dual wall formed from inner and outer layers separated by a compliant structure

    Science.gov (United States)

    Campbell,; Christian X. , Morrison; Jay, A [Oviedo, FL

    2011-12-20

    A turbine airfoil usable in a turbine engine with a cooling system and a compliant dual wall configuration configured to enable thermal expansion between inner and outer layers while eliminating stress formation is disclosed. The compliant dual wall configuration may be formed a dual wall formed from inner and outer layers separated by a compliant structure. The compliant structure may be configured such that the outer layer may thermally expand without limitation by the inner layer. The compliant structure may be formed from a plurality of pedestals positioned generally parallel with each other. The pedestals may include a first foot attached to a first end of the pedestal and extending in a first direction aligned with the outer layer, and may include a second foot attached to a second end of the pedestal and extending in a second direction aligned with the inner layer.

  16. Organizational form, local market structure and corporate social performance in retail

    OpenAIRE

    Utgård, Jakob

    2015-01-01

    I study how organizational form and local market structure influence retail firms' corporate social performance (CSP). The theoretical model is based on agency theory, which in its origin focuses on the dyad between the principal and the agent. I extend this perspective and examine how characteristics of the environment outside the dyad influence the outcomes. Retail stores vary in their organizational form and thereby in their incentives to maximize profits. I hypothesize that the different ...

  17. Structure of the cleavage-activated prefusion form of the parainfluenza virus 5 fusion protein.

    Science.gov (United States)

    Welch, Brett D; Liu, Yuanyuan; Kors, Christopher A; Leser, George P; Jardetzky, Theodore S; Lamb, Robert A

    2012-10-09

    The paramyxovirus parainfluenza virus 5 (PIV5) enters cells by fusion of the viral envelope with the plasma membrane through the concerted action of the fusion (F) protein and the receptor binding protein hemagglutinin-neuraminidase. The F protein folds initially to form a trimeric metastable prefusion form that is triggered to undergo large-scale irreversible conformational changes to form the trimeric postfusion conformation. It is thought that F refolding couples the energy released with membrane fusion. The F protein is synthesized as a precursor (F0) that must be cleaved by a host protease to form a biologically active molecule, F1,F2. Cleavage of F protein is a prerequisite for fusion and virus infectivity. Cleavage creates a new N terminus on F1 that contains a hydrophobic region, known as the FP, which intercalates target membranes during F protein refolding. The crystal structure of the soluble ectodomain of the uncleaved form of PIV5 F is known; here we report the crystal structure of the cleavage-activated prefusion form of PIV5 F. The structure shows minimal movement of the residues adjacent to the protease cleavage site. Most of the hydrophobic FP residues are buried in the uncleaved F protein, and only F103 at the newly created N terminus becomes more solvent-accessible after cleavage. The conformational freedom of the charged arginine residues that compose the protease recognition site increases on cleavage of F protein.

  18. Research Status on Reinforcement Connection Form of Precast Concrete Shear Wall Structure

    Science.gov (United States)

    Zhang, Zhuangnan; Zhang, Yan

    2018-03-01

    With the rapid development of Chinese economy and the speeding up the process of urbanization, housing industrialization has been paid more and more attention. And the fabricated structure has been widely used in China. The key of precast concrete shear wall structure is the connection of precast components. The reinforcement connection can directly affect the entirety performance and seismic behavior of the structure. Different reinforcement connections have a great impact on the overall behavior of the structure. By studying the characteristics of the reinforcement connection forms used in the vertical connection and horizontal connection of precast concrete shear wall, it can provide reference for the research and development of the reinforcement connection forms in the future.

  19. The quadratic-form identity for constructing the Hamiltonian structure of integrable systems

    International Nuclear Information System (INIS)

    Guo Fukui; Zhang Yufeng

    2005-01-01

    A usual loop algebra, not necessarily the matrix form of the loop algebra A-tilde n-1 , is also made use of for constructing linear isospectral problems, whose compatibility conditions exhibit a zero-curvature equation from which integrable systems are derived. In order to look for the Hamiltonian structure of such integrable systems, a quadratic-form identity is created in the present paper whose special case is just the trace identity; that is, when taking the loop algebra A-tilde 1 , the quadratic-form identity presented in this paper is completely consistent with the trace identity

  20. The retro-GCN4 leucine zipper sequence forms a stable three-dimensional structure

    Science.gov (United States)

    Mittl, Peer R. E.; Deillon, Christine; Sargent, David; Liu, Niankun; Klauser, Stephan; Thomas, Richard M.; Gutte, Bernd; Grütter, Markus G.

    2000-01-01

    The question of whether a protein whose natural sequence is inverted adopts a stable fold is still under debate. We have determined the 2.1-Å crystal structure of the retro-GCN4 leucine zipper. In contrast to the two-stranded helical coiled-coil GCN4 leucine zipper, the retro-leucine zipper formed a very stable, parallel four-helix bundle, which now lends itself to further structural and functional studies. PMID:10716989

  1. Factor Structure and Psychometric Properties of the Young Schema Questionnaire (Short Form) in Chinese Undergraduate Students

    Science.gov (United States)

    Cui, Lixia; Lin, Wenwen; Oei, Tian P. S.

    2011-01-01

    This study investigated cross-cultural differences in the factor structure and psychometric properties of the Young Schema Questionnaire (short form; YSQ-SF). The participants were 712 Chinese undergraduate students. The total sample was randomly divided into two sub-samples. Exploratory Factor Analysis (EFA) was conducted on questionnaire results…

  2. The Morphology of Intermediate Structures Formed During Bainite Transformation in HSLA Steels

    Science.gov (United States)

    Seidurov, Mikhail N.; Kovalev, Sergey V.; Zubkov, Alexander S.

    2017-10-01

    The paper deals with the structure of bainite formed under the influence of thermal deformation cycles of welding in low-carbon bainitic class steels. Morphology features associated with the formation of mesoferrite and granular bainite determines the high cold resistance of welded joints.

  3. THE DECISION OF FORM FOR DIFFRACTIVE STRUCTURES IN THE PROBLEM OF SCATTERING OF RADIO WAVES.

    Directory of Open Access Journals (Sweden)

    A. P. Preobrazhensky

    2017-02-01

    Full Text Available This paper considers the problem of scattering of electromagnetic waves in different diffraction structures. The solution of the scattering problem is based on the method of integral equations. On diagrams of backscattering at various frequencies of the incident wave, the decision about the form of the object is carried out.

  4. Crystal Structure of the Oligomeric Form of Lassa Virus Matrix Protein Z.

    Science.gov (United States)

    Hastie, Kathryn M; Zandonatti, Michelle; Liu, Tong; Li, Sheng; Woods, Virgil L; Saphire, Erica Ollmann

    2016-05-01

    The arenavirus matrix protein Z is highly multifunctional and occurs in both monomeric and oligomeric forms. The crystal structure of a dodecamer of Z from Lassa virus, presented here, illustrates a ring-like structure with a highly basic center. Mutagenesis demonstrates that the dimeric interface within the dodecamer and a Lys-Trp-Lys triad at the center of the ring are important for oligomerization. This structure provides an additional template to explore the many functions of Z. The arenavirus Lassa virus causes hundreds of thousands of infections each year, many of which develop into fatal hemorrhagic fever. The arenavirus matrix protein Z is multifunctional, with at least four distinct roles. Z exists in both monomeric and oligomeric forms, each of which likely serves a specific function in the viral life cycle. Here we present the dodecameric form of Lassa virus Z and demonstrate that Z forms a "wreath" with a highly basic center. This structure and that of monomeric Z now provide a pair of critical templates by which the multiple roles of Z in the viral life cycle may be interpreted. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  5. A resource-based theory of market structure and organizational form

    NARCIS (Netherlands)

    van Witteloostuijn, A.; Boone, C.A.J.J.

    We argue that combining the insights from both the industrial organization and organizational ecology perspectives is likely to produce value added. We develop a resource-based theory of market structure, where resources pertain to the environmental assets (together forming the resource space)

  6. Structure, diversity and evolution of protein toxins from spore-forming entomopathogenic bacteria

    NARCIS (Netherlands)

    Maagd, de R.A.; Bravo, A.; Berry, C.; Crickmore, N.; Schnepf, H.E.

    2003-01-01

    Gram-positive spore-forming entomopathogenic bacteria can utilize a large variety of protein toxins to help them invade, infect, and finally kill their hosts, through their action on the insect midgut. These toxins belong to a number of homology groups containing a diversity of protein structures

  7. On the structure of the space of geometric product-form models

    NARCIS (Netherlands)

    Bayer, Nimrod; Boucherie, Richardus J.

    2002-01-01

    This article deals with Markovian models defined on a finite-dimensional discrete state space and possess a stationary state distribution of a product-form. We view the space of such models as a mathematical object and explore its structure. We focus on models on an orthant [script Z]+n, which are

  8. Fortuitous structure determination of ‘as-isolated’ Escherichia coli bacterioferritin in a novel crystal form

    International Nuclear Information System (INIS)

    Eerde, André van; Wolterink-van Loo, Suzanne; Oost, John van der; Dijkstra, Bauke W.

    2006-01-01

    E. coli bacterioferritin was crystallized in a novel crystal form from different conditions and the structure was solved. The crystals belonged to space group P2 1 3 and diffracted to a resolution of 2.5 Å. Escherichia coli bacterioferritin was serendipitously crystallized in a novel cubic crystal form and its structure could be determined to 2.5 Å resolution despite a high degree of merohedral twinning. This is the first report of crystallographic data on ‘as-isolated’ E. coli bacterioferritin. The ferroxidase active site contains positive difference density consistent with two metal ions that had co-purified with the protein. X-ray fluorescence studies suggest that the metal composition is different from that of previous structures and is a mix of zinc and native iron ions. The ferroxidase-centre configuration displays a similar flexibility as previously noted for other bacterioferritins

  9. Structure of a second crystal form of Bence-Jones protein Loc: Strikingly different domain associations in two crystal forms of a single protein

    International Nuclear Information System (INIS)

    Schiffer, M.; Ainsworth, C.; Xu, Z.B.; Carperos, W.; Olsen, K.; Solomon, A.; Stevens, F.J.; Chang, C.H.

    1989-01-01

    The authors have determined the structure of the immunoglobulin light-chain dimer Loc in a second crystal form that was grown from distilled water. The crystal structure was determined to 2.8-angstrom resolution; the R factor is 0.22. The two variable domains are related by local 2-fold axes and form an antigen binding pocket. The variable domain-variable domain interaction observed in this crystal form differs from the one exhibited by the protein when crystallized from ammonium sulfate in which the two variable domains formed a protrusion. The structure attained in the distilled water crystals is similar to, but not identical with, the one observed for the Mcg light-chain dimer in crystals grown from ammonium sulfate. Thus, two strikingly different structures were attained by this multisubunit protein in crystals grown under two different, commonly used, crystallization techniques. The quaternary interactions exhibited by the protein in the two crystal forms are sufficiently different to suggest fundamentally different interpretations of the structural basis for the function of this protein. This observation may have general implications regarding the use of single crystallographic determinations for detailed identification of structural and functional relationships. On the other hand, proteins whose structures can be altered by manipulation of crystallization conditions may provide useful systems for study of fundamental structural chemistry

  10. Co thin film with metastable bcc structure formed on GaAs(111 substrate

    Directory of Open Access Journals (Sweden)

    Minakawa Shigeyuki

    2014-07-01

    Full Text Available Co thin films are prepared on GaAs(111 substrates at temperatures ranging from room temperature to 600 ºC by radio-frequency magnetron sputtering. The growth behavior and the detailed resulting film structure are investigated by in-situ reflection high-energy electron diffraction and X-ray diffraction. In early stages of film growth at temperatures lower than 200 ºC, Co crystals with metastable A2 (bcc structure are formed, where the crystal structure is stabilized through hetero-epitaxial growth. With increasing the film thickness beyond 2 nm, the metastable structure starts to transform into more stable A1 (fcc structure through atomic displacements parallel to the A2{110} close-packed planes. The crystallographic orientation relationship between the A2 and the transformed A1 crystals is A1{111} || A2{110}. When the substrate temperature is higher than 400 ºC, Ga atoms of substrate diffuse into the Co films and a Co-Ga alloy with bcc-based ordered structure of B2 is formed.

  11. Self-selection in size and structure in argon clusters formed on amorphous carbon

    Energy Technology Data Exchange (ETDEWEB)

    Krainyukova, Nina V.; Waal, Benjamin W. van de

    2004-07-01

    Argon clusters formed on an amorphous carbon substrate as deposited from the vapor phase were studied by means of transmission high energy electron diffraction using the liquid helium cryostat. Electron diffractograms were analysed on the basis of assumption that there exist a cluster size distribution in samples formed on substrate and multi-shell structures such as icosahedra, decahedra, fcc and hcp were probed for different sizes up to {approx}15 000 atoms. The experimental data were considered as a result of a superposition of diffracted intensities from clusters of different sizes and structures. The comparative analysis was based on the R-factor minimization that was found to be equal to 0.014 for the best fit between experiment and modelling. The total size and structure distribution function shows the presence of 'non-crystallographic' structures such as icosahedra and decahedra with five-fold symmetry that was found to prevail and a smaller amount of fcc and hcp structures. Possible growth mechanisms as well as observed general tendency to self-selection in sizes and structures are presumably governed by confined pore-like geometry in an amorphous carbon substrate.

  12. Structural origin of fractional Stokes-Einstein relation in glass-forming liquids.

    Science.gov (United States)

    Pan, Shaopeng; Wu, Z W; Wang, W H; Li, M Z; Xu, Limei

    2017-01-06

    In many glass-forming liquids, fractional Stokes-Einstein relation (SER) is observed above the glass transition temperature. However, the origin of such phenomenon remains elusive. Using molecular dynamics simulations, we investigate the break- down of SER and the onset of fractional SER in a model of metallic glass-forming liquid. We find that SER breaks down when the size of the largest cluster consisting of trapped atoms starts to increase sharply at which the largest cluster spans half of the simulations box along one direction, and the fractional SER starts to follows when the largest cluster percolates the entire system and forms 3-dimentional network structures. Further analysis based on the percolation theory also confirms that percolation occurs at the onset of the fractional SER. Our results directly link the breakdown of the SER with structure inhomogeneity and onset of the fraction SER with percolation of largest clusters, thus provide a possible picture for the break- down of SER and onset of fractional SER in glass-forming liquids, which is is important for the understanding of the dynamic properties in glass-forming liquids.

  13. Working Memory Training in the Form of Structured Games in Children with Attention Deficit Hyperactivity Disorder.

    Science.gov (United States)

    Khalili Kermani, Fatemeh; Mohammadi, Mohammad Reza; Yadegari, Fariba; Haresabadi, Fatemeh; Sadeghi, Seyed Mehdi

    2016-10-01

    Objective: In this study, a new training method of working memory (WM) was used in the form of structured games, and the effect of training was evaluated with a controlled design. The training method of WM in the form of structured games includes 20 sets of structured games that can improve WM and performance of executive functions. Method: Sixty children with attention deficit hyperactivity disorder (ADHD) aged 8.5 to 11.2 years (35 boys), using no stimulant medication were selected. We randomly assigned 30 participants to the experimental group and provided them with WM training. The training was in the form of structured games and was offered to the participants in two 60-minute sessions weekly for 12 weeks. Other participants were assigned to the control group, receiving no treatment. All the participants were also evaluated at follow-up 6 months later. The main measures were the Child Behavior Checklist (CBCL), the Digit Span and Symbol Search B subscale of the Wechsler Intelligence Scale for Children (WISC-IV); and scores of dictation and mathematics were used in terms of pre and post-test. Results: The results of the t-test revealed a significant improvement in the post-test measures as well as a significant reduction of parents' reports of inattentiveness, and improvement in academic performance in the experimental group. However, no significant changes were found in the control group. Conclusion : The academic and working memory improvements were primarily due to the training method of WM. Our findings suggest that the training method of WM in the form of structured games may be a practical method for treating children with ADHD, but it needs to be further investigated.

  14. Structural and optical properties of ZnO rods hydrothermally formed on polyethersulfone substrates

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Chang Mi; Jang, Jin Tak; Kim, Chang Yong; Ryu, Hyuk Hyun [Inje University, Gimhae (Korea, Republic of); Lee, Won Jae [Dong-Eui University, Busan (Korea, Republic of); Chang, Ji Ho [Korea Maritime University, Busan (Korea, Republic of); Son, Chang Sik [Silla University, Busan (Korea, Republic of); Choi, Hee Lack [Pukyong National University, Busan (Korea, Republic of)

    2012-06-15

    Various unique ZnO morphologies, such as cigar-like and belt-like structures and microrod and nanorod structures, were formed on flexible polyethersulfone (PES) substrates by using a low temperature hydrothermal route. The structural properties of ZnO depended highly on the precursor concentration. The effect of a thin ZnO seed layer deposited the on PES substrate by using atomic layer deposition on the structural and the optical properties of ZnO hydrothermally grown on the ZnO seed layer/PES substrates was studied. Field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), and photoluminescence (PL) measurements were employed to analyze the characteristics of hydrothermally-grown ZnO. The diameter of the ZnO nanorods grown on the ZnO seed layer/PES substrates increased with increasing precursor concentration from 0.025 to 0.125 M due to the Ostwald ripening process. ZnO hydrothermally-grown on the ZnO seed layer/PES substrates at a low precursor concentration showed better structural properties than ZnO formed without a seed layer. Well-formed ZnO nanorods deposited on the ZnO seed layer/PES substrates showed two PL peaks, one in the ultraviolet and the other in the visible region, whereas horizontally positioned ZnO formed on the PES substrate in the absence of a seed layer emitted only one broad PL peak in the violet region. The ZnO grown on PES substrates in this work can be used as high-quality transparent electrodes for solar cells fabricated on flexible substrates.

  15. Structural and optical properties of ZnO rods hydrothermally formed on polyethersulfone substrates

    International Nuclear Information System (INIS)

    Shin, Chang Mi; Jang, Jin Tak; Kim, Chang Yong; Ryu, Hyuk Hyun; Lee, Won Jae; Chang, Ji Ho; Son, Chang Sik; Choi, Hee Lack

    2012-01-01

    Various unique ZnO morphologies, such as cigar-like and belt-like structures and microrod and nanorod structures, were formed on flexible polyethersulfone (PES) substrates by using a low temperature hydrothermal route. The structural properties of ZnO depended highly on the precursor concentration. The effect of a thin ZnO seed layer deposited the on PES substrate by using atomic layer deposition on the structural and the optical properties of ZnO hydrothermally grown on the ZnO seed layer/PES substrates was studied. Field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), and photoluminescence (PL) measurements were employed to analyze the characteristics of hydrothermally-grown ZnO. The diameter of the ZnO nanorods grown on the ZnO seed layer/PES substrates increased with increasing precursor concentration from 0.025 to 0.125 M due to the Ostwald ripening process. ZnO hydrothermally-grown on the ZnO seed layer/PES substrates at a low precursor concentration showed better structural properties than ZnO formed without a seed layer. Well-formed ZnO nanorods deposited on the ZnO seed layer/PES substrates showed two PL peaks, one in the ultraviolet and the other in the visible region, whereas horizontally positioned ZnO formed on the PES substrate in the absence of a seed layer emitted only one broad PL peak in the violet region. The ZnO grown on PES substrates in this work can be used as high-quality transparent electrodes for solar cells fabricated on flexible substrates.

  16. Novel dextran derivatives with unconventional structure formed in an efficient one-pot reaction.

    Science.gov (United States)

    Hotzel, Konrad; Heinze, Thomas

    2016-11-03

    An efficient one-pot synthesis of new dextran derivatives is described. The functional groups of β-alanine, i.e., the carboxyl- and amine group, are converted independently in one-step by iminium chloride to form products with a single substituent. The dextran N-[(dimethylamino)methylene]-β-alanine ester is formed selectively. The structure of the resulting polymers is unambiguously determined by means of NMR- and FTIR-spectroscopy and elemental analysis. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. An efficient closed-form solution for acoustic emission source location in three-dimensional structures

    Directory of Open Access Journals (Sweden)

    Xibing Li

    2014-02-01

    Full Text Available This paper presents an efficient closed-form solution (ECS for acoustic emission(AE source location in three-dimensional structures using time difference of arrival (TDOA measurements from N receivers, N ≥ 6. The nonlinear location equations of TDOA are simplified to linear equations. The unique analytical solution of AE sources for unknown velocity system is obtained by solving the linear equations. The proposed ECS method successfully solved the problems of location errors resulting from measured deviations of velocity as well as the existence and multiplicity of solutions induced by calculations of square roots in existed close-form methods.

  18. Modelling and simulating the forming of new dry automated lay-up reinforcements for primary structures

    Science.gov (United States)

    Bouquerel, Laure; Moulin, Nicolas; Drapier, Sylvain; Boisse, Philippe; Beraud, Jean-Marc

    2017-10-01

    While weight has been so far the main driver for the development of prepreg based-composites solutions for aeronautics, a new weight-cost trade-off tends to drive choices for next-generation aircrafts. As a response, Hexcel has designed a new dry reinforcement type for aircraft primary structures, which combines the benefits of automation, out-of-autoclave process cost-effectiveness, and mechanical performances competitive to prepreg solutions: HiTape® is a unidirectional (UD) dry carbon reinforcement with thermoplastic veil on each side designed for aircraft primary structures [1-3]. One privileged process route for HiTape® in high volume automated processes consists in forming initially flat dry reinforcement stacks, before resin infusion [4] or injection. Simulation of the forming step aims at predicting the geometry and mechanical properties of the formed stack (so-called preform) for process optimisation. Extensive work has been carried out on prepreg and dry woven fabrics forming behaviour and simulation, but the interest for dry non-woven reinforcements has emerged more recently. Some work has been achieved on non crimp fabrics but studies on the forming behaviour of UDs are seldom and deal with UD prepregs only. Tension and bending in the fibre direction, along with inter-ply friction have been identified as the main mechanisms controlling the HiTape® response during forming. Bending has been characterised using a modified Peirce's flexometer [5] and inter-ply friction study is under development. Anisotropic hyperelastic constitutive models have been selected to represent the assumed decoupled deformation mechanisms. Model parameters are then identified from associated experimental results. For forming simulation, a continuous approach at the macroscopic scale has been selected first, and simulation is carried out in the Zset framework [6] using proper shell finite elements.

  19. Generating Free-Form Grid Truss Structures from 3D Scanned Point Clouds

    Directory of Open Access Journals (Sweden)

    Hui Ding

    2017-01-01

    Full Text Available Reconstruction, according to physical shape, is a novel way to generate free-form grid truss structures. 3D scanning is an effective means of acquiring physical form information and it generates dense point clouds on surfaces of objects. However, generating grid truss structures from point clouds is still a challenge. Based on the advancing front technique (AFT which is widely used in Finite Element Method (FEM, a scheme for generating grid truss structures from 3D scanned point clouds is proposed in this paper. Based on the characteristics of point cloud data, the search box is adopted to reduce the search space in grid generating. A front advancing procedure suit for point clouds is established. Delaunay method and Laplacian method are used to improve the quality of the generated grids, and an adjustment strategy that locates grid nodes at appointed places is proposed. Several examples of generating grid truss structures from 3D scanned point clouds of seashells are carried out to verify the proposed scheme. Physical models of the grid truss structures generated in the examples are manufactured by 3D print, which solidifies the feasibility of the scheme.

  20. Impact of growth temperature on the crystal habits, forms and structures of VO2 nanocrystals

    International Nuclear Information System (INIS)

    Loeffler, Stefan; Auer, Erwin; Lugstein, Alois; Bertagnolli, Emmerich; Weil, Matthias

    2011-01-01

    We investigated the impact of the process temperature on the habits, forms and crystal structure of VO 2 nanocrystals grown by a vapor-transport method on (0001) quartz substrates. Four distinct growth regimes were discerned: orthorhombic nanowires, sheets, hemispheres, and nanowires with a monoclinic structure. The nanostructures were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM). I/V characterization of individual nanowires was enabled by Ti/Au contact formation via electron beam lithography and lift-off techniques. The expected metal-insulator transition (MIT) was found in monoclinic VO 2 nanowires. (orig.)

  1. Magnetic form factors of the trinucleons

    Energy Technology Data Exchange (ETDEWEB)

    Schiavilla, R; Pandharipande, V R; Riska, Dan-Olof

    1989-11-01

    The magnetic form factors of 3H and 3He are calculated with the Monte Carlo method from variational ground-state wave functions obtained for the Argonne and Urbana two- and three-nucleon interactions. The electromagnetic current operator contains one- and two-body terms that are constructed so as to satisfy the continuity equation with the two-nucleon potential in the Hamiltonian. The results obtained with the Argonne two-nucleon interaction are in overall agreement with the empirical values. It appears that the remaining theoretical uncertainty, in the calculation of these form factors from a given interaction model, is dominated by that in the electromagnetic form factors of the nucleon. It is found that the isovector magnetic form factors are rather sensitive to the details of the isospin-dependent tensor force, and they are much better reproduced with the Argonne than the Urbana potential. The isoscalar magnetic form factors appear to be sensitive to the spin-orbit interactions, and are better reproduced with the Urbana potential. The Argonne potential has a stronger τ1∙τ2 tensor force, while the Urbana one has a shorter-range spin-orbit interaction.

  2. Structure of massive star forming clumps from the Red MSX Source Survey

    Science.gov (United States)

    Figura, Charles C.; Urquhart, J. S.; Morgan, L.

    2014-01-01

    We present ammonia (1,1) and (2,2) emission maps of 61 high-mass star forming regions drawn from the Red MSX Source (RMS) Survey and observed with the Green Bank Telescope's K-Band Focal Plane Array. We use these observations to investigate the spatial distribution of the environmental conditions associated with this sample of embedded massive young stellar objects (MYSOs). Ammonia is an excellent high-density tracer of star-forming regions as its hyperfine structure allows relatively simple characterisation of the molecular environment. These maps are used to measure the column density, kinetic gas temperature distributions and velocity structure across these regions. We compare the distribution of these properties to that of the associated dust and mid-infrared emission traced by the ATLASGAL 870 micron emission maps and the Spitzer GLIMPSE IRAC images. We present a summary of these results and highlight some of more interesting finds.

  3. The effect of form pressure on the air void structure of SCC

    DEFF Research Database (Denmark)

    Jensen, Mikkel Vibæk; Hasholt, Marianne Tange; Geiker, Mette Rica

    2005-01-01

    The high workability of self-compacting concrete (SCC) invites to high casting rates. However, casting walls at high rate may result in large pressure at the bottom of the form and subsequently compression of the air voids. This paper deals with the influence of hydrostatic pressure during setting...... on the air void structure of hardened, air entrained SCC. The subject was examined through laboratory investigations of SCC with two different amounts of air entrainment. The condition in the form was simulated by using containers making it possible to cure concrete under various pressures corresponding...... to the bottom of castings of 0, 2, 4, and 6 meters height. The laboratory investigations were supplemented with data from two full-scale wall castings. The air void structure of the hardened concretes was determined on plane sections. The results indicate that the pressure related changes of the air void...

  4. Advances in Design and Fabrication of Free-Form Reciprocal Structures

    DEFF Research Database (Denmark)

    Parigi, Dario

    2016-01-01

    The paper presents the advances in design and fabrication of free-form Reciprocal Structures, and their application a during a one-week long workshop with the students of the 1st semester of the Master of Science in Architecture and Design, fall 2015, at Aalborg University. Two new factors were...... introduced and tested: a new version of the software Reciprocalizer, and an evolution of the Reciprocalizer Robot. The workshop didactic framework Performance Aided/Assisted Design (PAD) is presented....

  5. Study of the technology of the plasma nanostructuring of silicon to form highly efficient emission structures

    Energy Technology Data Exchange (ETDEWEB)

    Galperin, V. A.; Kitsyuk, E. P. [“Technological Center” Research-and-Production Company (Russian Federation); Pavlov, A. A. [Russian Academy of Sciences, Institute of Nanotechnologies in Microelectronics (Russian Federation); Shamanaev, A. A., E-mail: artemiy.shamanaev@tcen.ru [“Technological Center” Research-and-Production Company (Russian Federation)

    2015-12-15

    New methods for silicon nanostructuring and the possibility of raising the aspect ratios of the structures being formed are considered. It is shown that the technology developed relates to self-formation methods and is an efficient tool for improving the quality of field-emission cathodes based on carbon nanotubes (CNTs) by increasing the Si–CNT contact area and raising the efficiency of the heat sink.

  6. What Factors Affect Doctors' Hours Decisions: Comparing Structural Discrete Choice and Reduced-Form Approaches

    OpenAIRE

    Kalb, Guyonne; Kühnle, Daniel; Scott, Anthony; Cheng, Terence Chai; Jeon, Sung-Hee

    2015-01-01

    Few papers examine the pecuniary and non-pecuniary determinants of doctors' labour supply despite substantial predicted shortages in many OECD countries. We contribute to the literature by applying both a structural discrete choice and a reduced-form approach. Using detailed survey data for Australian physicians, we examine how these different modelling approaches affect estimated wage elasticities at the intensive margin. We show that all modelling approaches predict small negative wage elas...

  7. Structure of a new crystal form of human Hsp70 ATPase domain.

    Science.gov (United States)

    Osipiuk, J; Walsh, M A; Freeman, B C; Morimoto, R I; Joachimiak, A

    1999-05-01

    Hsp70 proteins are highly conserved proteins induced by heat shock and other stress conditions. An ATP-binding domain of human Hsp70 protein has been crystallized in two major morphological forms at pH 7.0 in the presence of PEG 8000 and CaCl2. Both crystal forms belong to the orthorhombic space group P212121, but show no resemblance in unit-cell parameters. Analysis of the crystal structures for both forms shows a 1-2 A shift of one of the subdomains of the protein. This conformational change could reflect a 'natural' flexibility of the protein which might be relevant to ATP binding and may facilitate the interaction of other proteins with Hsp70 protein.

  8. Structural and functional changes across the visual cortex of a patient with visual form agnosia.

    Science.gov (United States)

    Bridge, Holly; Thomas, Owen M; Minini, Loredana; Cavina-Pratesi, Cristiana; Milner, A David; Parker, Andrew J

    2013-07-31

    Loss of shape recognition in visual-form agnosia occurs without equivalent losses in the use of vision to guide actions, providing support for the hypothesis of two visual systems (for "perception" and "action"). The human individual DF received a toxic exposure to carbon monoxide some years ago, which resulted in a persisting visual-form agnosia that has been extensively characterized at the behavioral level. We conducted a detailed high-resolution MRI study of DF's cortex, combining structural and functional measurements. We present the first accurate quantification of the changes in thickness across DF's occipital cortex, finding the most substantial loss in the lateral occipital cortex (LOC). There are reduced white matter connections between LOC and other areas. Functional measures show pockets of activity that survive within structurally damaged areas. The topographic mapping of visual areas showed that ordered retinotopic maps were evident for DF in the ventral portions of visual cortical areas V1, V2, V3, and hV4. Although V1 shows evidence of topographic order in its dorsal portion, such maps could not be found in the dorsal parts of V2 and V3. We conclude that it is not possible to understand fully the deficits in object perception in visual-form agnosia without the exploitation of both structural and functional measurements. Our results also highlight for DF the cortical routes through which visual information is able to pass to support her well-documented abilities to use visual information to guide actions.

  9. Structural analysis of surface film on alloy 600 formed under environment of PWR primary water

    Energy Technology Data Exchange (ETDEWEB)

    Terachi, Takumi; Totsuka, Nobuo; Yamada, Takuyo; Nakagawa, Tomokazu [Inst. of Nuclear Safety System Inc., Mihama, Fukui (Japan); Deguchi, Hiroshi [Kansai Electric Power Co., Inc., Osaka (Japan); Horiuchi, Masaki; Oshitani, Masato [Kanden Kako Co., Ltd., Osaka (Japan)

    2002-09-01

    It has been shown by one of the present authors and so forth that PWSCC of alloy 600 relates to dissolved hydrogen concentration (DH) in water and oxide film structure. However, the mechanism of PWSCC has not been clear yet. Therefore, in order to investigate relationship between them, structural analysis of the oxide film formed under the environment of PWR primary water was carried out by using X-ray diffraction, the scanning electron microscope and the transmission electron microscope. Especially, to perform accurate analysis, the synchrotron orbital radiation with SPring-8 was tried to use for thin film X-ray diffraction measurement. From the results, observed are as follows: 1. the oxide film is mainly composed of NiO, under the condition without hydrogen. 2. In the environment of DH 2.75ppm, the oxide film forms thin spinel structures. 3. On the other hand, needlelike oxides are formed at DH 1ppm. For this reason, around 1ppm of DH there would be the boundary that stable NiO and spinel oxide generate, and it agrees with the peak range of the PWSCC susceptibility on hydrogen. From this, it is suggested that the boundary of NiO/spinel oxide affects the SCC susceptibility. (author)

  10. Structural study of salt forms of amides; paracetamol, benzamide and piperine

    Science.gov (United States)

    Kennedy, Alan R.; King, Nathan L. C.; Oswald, Iain D. H.; Rollo, David G.; Spiteri, Rebecca; Walls, Aiden

    2018-02-01

    Single crystal x-ray diffraction has been used to investigate the structures of six complexes containing O-atom protonated cations derived from the pharmaceutically relevant amides benzamide (BEN), paracetamol (PAR) and piperine (PIP). The structures of the salt forms [PAR(H)][SO3C6H4Cl], [BEN(H)][O3SC6H4Cl] and [BEN(H)][Br]·H2O are reported along with those of the hemi-halide salt forms [PAR(H)][I3]. PAR, [PIP(H)][I3]·PIP and [PIP(H)][I3]0·5[I]0.5. PIP. The structure of the cocrystal BEN. HOOCCH2Cl is also presented for comparison. The geometry of the amide group is found to systematically change upon protonation, with the Cdbnd O distance increasing and the Csbnd N distance decreasing. The hemi-halide species all feature strongly hydrogen bonded amide(H)/amide pairs. The amide group Cdbnd O and Csbnd N distances for both elements of each such pair are intermediate between those found for simple neutral amide and protonated amide forms. It was found that crystallising paracetamol from aqueous solutions containing Ba2+ ions gave orthorhombic paracetamol.

  11. First principles study of structural, electronic and optical properties of polymorphic forms of Rb 2Te

    Science.gov (United States)

    Alay-e-Abbas, S. M.; Shaukat, A.

    2011-05-01

    First-principles density functional theory calculations have been performed for structural, electronic and optical properties of three polymorphic forms of rubidium telluride. Our calculations show that the sequence of pressure induced phase transitions for Rb 2Te is Fm3¯m → Pnma → P6 3/mmc which is governed by the coordination numbers of the anions. From our calculated low transition pressure value for the Fm3¯m phase to the Pnma phase transition of Rb 2Te, the experimentally observed meta-stability of Fm3¯m phase at ambient conditions seems reasonable. The electronic band structure has been calculated for all the three phases and the change in the energy band gap is discussed for the transitioning phases. The energy band gaps obtained for the three phases of Rb 2Te decrease on going from the meta-stable phase to the high-pressure phases. Total and partial density of states for the polymorphs of Rb 2Te has been computed to elucidate the contribution of various atomic states on the electronic band structure. Furthermore, optical properties for all the polymorphic forms have been presented in form of the complex dielectric function.

  12. Structure and Oxidation of Pyrrole Adducts Formed between Aflatoxin B2a and Biological Amines.

    Science.gov (United States)

    Rushing, Blake R; Selim, Mustafa I

    2017-06-19

    Aflatoxin B 2a has been shown to bind to proteins through a dialdehyde intermediate under physiological conditions. The proposed structure of this adduct has been published showing a Schiff base interaction, but adequate verification using structural elucidation instrumental techniques has not been performed. In this work, we synthesized the aflatoxin B 2a amino acid adduct under alkaline conditions, and the formation of a new product was determined using high performance liquid chromatography-time-of-flight mass spectrometry. The resulting accurate mass was used to generate a novel proposed chemical structure of the adduct in which the dialdehyde forms a pyrrole ring with primary amines rather than the previously proposed Schiff base interaction. The pyrrole structure was confirmed using 1 H, 13 C, correlation spectroscopy, heteronuclear single quantum correlation, and heteronuclear multiple bond correlation NMR and tandem mass spectrometry. Reaction kinetics show that the reaction is overall second order and that the rate increases as pH increases. Additionally, this study shows for the first time that aflatoxin B 2a dialdehyde forms adducts with phosphatidylethanolamines and does so through pyrrole ring formation, which makes it the first aflatoxin-lipid adduct to be structurally identified. Furthermore, oxidation of the pyrrole adduct produced a product that was 16 m/z heavier. When the aflatoxin B 2a -lysine (ε) adduct was oxidized, it gave a product with an accurate mass, mass fragmentation pattern, and 1 H NMR spectrum that match aflatoxin B 1 -lysine, which suggest the transformation of the pyrrole ring to a pyrrolin-2-one ring. These data give new insight into the fate and chemical properties of biological adducts formed from aflatoxin B 2a as well as possible interferences with known aflatoxin B 1 exposure biomarkers.

  13. A novel fungal fruiting structure formed by Aspergillus niger and Aspergillus carbonarius in grape berries.

    Science.gov (United States)

    Pisani, Cristina; Nguyen, Trang Thoaivan; Gubler, Walter Douglas

    2015-09-01

    Sour rot, is a pre-harvest disease that affects many grape varieties. Sour rot symptoms include initial berry cracking and breakdown of berry tissue. This is a disease complex with many filamentous fungi and bacteria involved, but is usually initiated by Aspergillus niger or Aspergillus carbonarius. Usually, by the time one sees the rot there are many other organisms involved and it is difficult to attribute the disease to one species. In this study two species of Aspergillus were shown to produce a previously unknown fruiting structure in infected berries. The nodulous morphology, bearing conidia, suggests them to be an 'everted polymorphic stroma'. This structure forms freely inside the berry pulp and assumes multiple shapes and sizes, sometimes sclerotium-like in form. It is composed of a mass of vegetative hyphae with or without tissue of the host containing spores or fruiting bodies bearing spores. Artificially inoculated berries placed in soil in winter showed the possible overwintering function of the fruiting body. Inoculated berry clusters on standing vines produced fruiting structures within 21 d post inoculation when wounds were made at veraison or after (July-September). Histological studies confirmed that the fruiting structure was indeed fungal tissue. Copyright © 2015 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.

  14. The Open Form Inducer Approach for Structure-Based Drug Design.

    Directory of Open Access Journals (Sweden)

    Daniel Ken Inaoka

    Full Text Available Many open form (OF structures of drug targets were obtained a posteriori by analysis of co-crystals with inhibitors. Therefore, obtaining the OF structure of a drug target a priori will accelerate development of potent inhibitors. In addition to its small active site, Trypanosoma cruzi dihydroorotate dehydrogenase (TcDHODH is fully functional in its monomeric form, making drug design approaches targeting the active site and protein-protein interactions unrealistic. Therefore, a novel a priori approach was developed to determination the TcDHODH active site in OF. This approach consists of generating an "OF inducer" (predicted in silico to bind the target and cause steric repulsion with flexible regions proximal to the active site that force it open. We provide the first proof-of-concept of this approach by predicting and crystallizing TcDHODH in complex with an OF inducer, thereby obtaining the OF a priori with its subsequent use in designing potent and selective inhibitors. Fourteen co-crystal structures of TcDHODH with the designed inhibitors are presented herein. This approach has potential to encourage drug design against diseases where the molecular targets are such difficult proteins possessing small AS volume. This approach can be extended to study open/close conformation of proteins in general, the identification of allosteric pockets and inhibitors for other drug targets where conventional drug design approaches are not applicable, as well as the effective exploitation of the increasing number of protein structures deposited in Protein Data Bank.

  15. Superplastic Forming/Adhesive Bonding of Aluminum (SPF/AB) Multi-Sheet Structures

    Science.gov (United States)

    Wagner, John A. (Technical Monitor); Will, Jeff D.; Cotton, James D.

    2003-01-01

    A significant fraction of airframe structure consists of stiffened panels that are costly and difficult to fabricate. This program explored a potentially lower-cost processing route for producing such panels. The alternative process sought to apply concurrent superplastic forming and adhesive bonding of aluminum alloy sheets. Processing conditions were chosen to balance adequate superplasticity of the alloy with thermal stability of the adhesive. As a first objective, an air-quenchable, superplastic aluminum-lithium alloy and a low-volatile content, low-viscosity adhesive with compatible forming/curing cycles were identified. A four-sheet forming pack was assembled which consisted of a welded two-sheet core separated from the face sheets by a layer of adhesive. Despite some preliminary success, of over 30 forming trials none was completely successful. The main problem was inadequate superplasticity in the heat-affected zones of the rib welds, which generally fractured prior to completion of the forming cycle. The welds are a necessary component in producing internal ribs by the 'four-sheet' process. Other challenges, such as surface preparation and adhesive bonding, were adequately solved. But without the larger issue of tearing at the weld locations, complex panel fabrication by SPF/AB does not appear viable.

  16. Structural Determinants of Photoreactivity of Triplex Forming Oligonucleotides Conjugated to Psoralens

    Science.gov (United States)

    Krishnan, Rajagopal; Oh, Dennis H.

    2010-01-01

    Triplex-forming oligonucleotides (TFOs) with both DNA and 2′-O-methyl RNA backbones can direct psoralen photoadducts to specific DNA sequences. However, the functional consequences of these differing structures on psoralen photoreactivity are unknown. We designed TFO sequences with DNA and 2′-O-methyl RNA backbones conjugated to psoralen by 2-carbon linkers and examined their ability to bind and target damage to model DNA duplexes corresponding to sequences within the human HPRT gene. While TFO binding affinity was not dramatically affected by the type of backbone, psoralen photoreactivity was completely abrogated by the 2′-O-methyl RNA backbone. Photoreactivity was restored when the psoralen was conjugated to the RNA TFO via a 6-carbon linker. In contrast to the B-form DNA of triplexes formed by DNA TFOs, the CD spectra of triplexes formed with 2′-O-methyl RNA TFOs exhibited features of A-form DNA. These results indicate that 2′-O-methyl RNA TFOs induce a partial B-to-A transition in their target DNA sequences which may impair the photoreactivity of a conjugated psoralen and suggest that optimal design of TFOs to target DNA damage may require a balance between binding ability and drug reactivity. PMID:20725628

  17. Form and function: Perspectives on structural biology and resources for the future

    International Nuclear Information System (INIS)

    Vaughan, D.

    1990-12-01

    The purpose of this study is largely to explore and expand on the thesis that biological structures and their functions are suited to. Form indeed follows function and if we are to understand the workings of a living system, with all that such an understanding promises, we must first seek to describe the structure of its parts. Descriptions of a few achievements of structural biology lay the groundwork, but the substance of this booklet is a discussion of important questions yet unanswered and opportunities just beyond our grasp. The concluding pages then outline a course of action in which the Department of Energy would exercise its responsibility to develop the major resources needed to extend our reach and to answer some of those unanswered questions. 22 figs

  18. Revealing the Link between Structural Relaxation and Dynamic Heterogeneity in Glass-Forming Liquids.

    Science.gov (United States)

    Wang, Lijin; Xu, Ning; Wang, W H; Guan, Pengfei

    2018-03-23

    Despite the use of glasses for thousands of years, the nature of the glass transition is still mysterious. On approaching the glass transition, the growth of dynamic heterogeneity has long been thought to play a key role in explaining the abrupt slowdown of structural relaxation. However, it still remains elusive whether there is an underlying link between structural relaxation and dynamic heterogeneity. Here, we unravel the link by introducing a characteristic time scale hiding behind an identical dynamic heterogeneity for various model glass-forming liquids. We find that the time scale corresponds to the kinetic fragility of liquids. Moreover, it leads to scaling collapse of both the structural relaxation time and dynamic heterogeneity for all liquids studied, together with a characteristic temperature associated with the same dynamic heterogeneity. Our findings imply that studying the glass transition from the viewpoint of dynamic heterogeneity is more informative than expected.

  19. Infrared spectroscopy study of structural changes in glass-forming salol.

    Science.gov (United States)

    Baran, J; Davydova, N A

    2010-03-01

    We report the investigation of glass-forming salol upon different courses of the temperature changes from liquid to glass state and back using FT-IR spectroscopy measurements in the wide spectral and temperature ranges. The formation of the ordered clusters in supercooled liquid salol has been observed at 250 K. When the temperature is decreased further to 11 K these ordered clusters become an element of the glass structure. With increasing temperature to 270 K through the glass transition noticeable evolutions of the IR spectrum occurs up till the ordered clusters are developed into crystal. So produced crystal melts in the temperature range 300-310 K, that corresponds to the melting temperature of the metastable phase (Tmelt=302 K) . Thus, the crystalline structure of the ordered clusters corresponds to the structure of metastable phase and is monoclinic.

  20. Form and function: Perspectives on structural biology and resources for the future

    Energy Technology Data Exchange (ETDEWEB)

    Vaughan, D. (ed.)

    1990-12-01

    The purpose of this study is largely to explore and expand on the thesis that biological structures and their functions are suited to. Form indeed follows function and if we are to understand the workings of a living system, with all that such an understanding promises, we must first seek to describe the structure of its parts. Descriptions of a few achievements of structural biology lay the groundwork, but the substance of this booklet is a discussion of important questions yet unanswered and opportunities just beyond our grasp. The concluding pages then outline a course of action in which the Department of Energy would exercise its responsibility to develop the major resources needed to extend our reach and to answer some of those unanswered questions. 22 figs.

  1. Revealing the Link between Structural Relaxation and Dynamic Heterogeneity in Glass-Forming Liquids

    Science.gov (United States)

    Wang, Lijin; Xu, Ning; Wang, W. H.; Guan, Pengfei

    2018-03-01

    Despite the use of glasses for thousands of years, the nature of the glass transition is still mysterious. On approaching the glass transition, the growth of dynamic heterogeneity has long been thought to play a key role in explaining the abrupt slowdown of structural relaxation. However, it still remains elusive whether there is an underlying link between structural relaxation and dynamic heterogeneity. Here, we unravel the link by introducing a characteristic time scale hiding behind an identical dynamic heterogeneity for various model glass-forming liquids. We find that the time scale corresponds to the kinetic fragility of liquids. Moreover, it leads to scaling collapse of both the structural relaxation time and dynamic heterogeneity for all liquids studied, together with a characteristic temperature associated with the same dynamic heterogeneity. Our findings imply that studying the glass transition from the viewpoint of dynamic heterogeneity is more informative than expected.

  2. Referral letter with an attached structured reply form: Is it a solution for not getting replies

    Directory of Open Access Journals (Sweden)

    R. P. J. C. Ramanayake

    2013-01-01

    Full Text Available Background: Communication between primary care doctors and specialists/hospital doctors is vital for smooth functioning of a health care system. In many instances referral and reply letters are the sole means of communication between general practitioners and hospital doctors/specialists. Despite the obvious benefits to patient care, answers to referral letters are the exception worldwide. In Sri Lanka hand written conventional letters are used to refer patients and replies are scarce. Materials and Methods: This interventional study was designed to assess if attaching a structured reply form with the referral letter would increase the rate of replies/back-referrals. It was conducted at the Family Medicine Clinic of the Faculty of Medicine, University of Kelaniya. A structured referral letter (form was designed based on guide lines and literature and it was used for referral of patients for a period of six months. Similarly a structured reply form was also designed and both the referral letter and the reply letter were printed on A4 papers side by side and these were used for the next six months for referrals. Both letters had headings and space underneath to write details pertaining to the patient. A register was maintained to document the number of referrals and replies received during both phases. Patents were asked to return the reply letters if specialists/hospital doctors obliged to reply. Results: Total of 90 patients were referred using the structured referral form during 1st phase. 80 letters (with reply form attached were issued during the next six months. Patients were referred to eight different specialties. Not a single reply during the 1 st phase and there were six 6 (7.5% replies during the 2 nd phase. Discussion: This was an attempt to improve communication between specialists/hospital doctors and primary care doctors. Even though there was some improvement it was not satisfactory. A multicenter island wide study should be

  3. Discrete-time Calogero-Moser system and Lagrangian 1-form structure

    International Nuclear Information System (INIS)

    Yoo-Kong, Sikarin; Lobb, Sarah; Nijhoff, Frank

    2011-01-01

    We study the Lagrange formalism of the (rational) Calogero-Moser (CM) system, both in discrete time and continuous time, as a first example of a Lagrangian 1-form structure in the sense of the recent paper (Lobb and Nijhoff 2009 J. Phys. A: Math. Theor.42 454013). The discrete-time model of the CM system was established some time ago arising as a pole reduction of a semi-discrete version of the Kadomtsev-Petviashvili (KP) equation, and was shown to lead to an exactly integrable correspondence (multivalued map). In this paper, we present the full KP solution based on the commutativity of the discrete-time flows in the two discrete KP variables. The compatibility of the corresponding Lax matrices is shown to lead directly to the relevant closure relation on the level of the Lagrangians. Performing successive continuum limits on both the level of the KP equation and the level of the CM system, we establish the proper Lagrangian 1-form structure for the continuum case of the CM model. We use the example of the three-particle case to elucidate the implementation of the novel least-action principle, which was presented in Lobb and Nijhoff (2009), for the simpler case of Lagrangian 1-forms. (paper)

  4. Form and function in hillslope hydrology: in situ imaging and characterization of flow-relevant structures

    Directory of Open Access Journals (Sweden)

    C. Jackisch

    2017-07-01

    Full Text Available The study deals with the identification and characterization of rapid subsurface flow structures through pedo- and geo-physical measurements and irrigation experiments at the point, plot and hillslope scale. Our investigation of flow-relevant structures and hydrological responses refers to the general interplay of form and function, respectively. To obtain a holistic picture of the subsurface, a large set of different laboratory, exploratory and experimental methods was used at the different scales. For exploration these methods included drilled soil core profiles, in situ measurements of infiltration capacity and saturated hydraulic conductivity, and laboratory analyses of soil water retention and saturated hydraulic conductivity. The irrigation experiments at the plot scale were monitored through a combination of dye tracer, salt tracer, soil moisture dynamics, and 3-D time-lapse ground penetrating radar (GPR methods. At the hillslope scale the subsurface was explored by a 3-D GPR survey. A natural storm event and an irrigation experiment were monitored by a dense network of soil moisture observations and a cascade of 2-D time-lapse GPR trenches. We show that the shift between activated and non-activated state of the flow paths is needed to distinguish structures from overall heterogeneity. Pedo-physical analyses of point-scale samples are the basis for sub-scale structure inference. At the plot and hillslope scale 3-D and 2-D time-lapse GPR applications are successfully employed as non-invasive means to image subsurface response patterns and to identify flow-relevant paths. Tracer recovery and soil water responses from irrigation experiments deliver a consistent estimate of response velocities. The combined observation of form and function under active conditions provides the means to localize and characterize the structures (this study and the hydrological processes (companion study Angermann et al., 2017, this issue.

  5. Form and function in hillslope hydrology: in situ imaging and characterization of flow-relevant structures

    Science.gov (United States)

    Jackisch, Conrad; Angermann, Lisa; Allroggen, Niklas; Sprenger, Matthias; Blume, Theresa; Tronicke, Jens; Zehe, Erwin

    2017-07-01

    The study deals with the identification and characterization of rapid subsurface flow structures through pedo- and geo-physical measurements and irrigation experiments at the point, plot and hillslope scale. Our investigation of flow-relevant structures and hydrological responses refers to the general interplay of form and function, respectively. To obtain a holistic picture of the subsurface, a large set of different laboratory, exploratory and experimental methods was used at the different scales. For exploration these methods included drilled soil core profiles, in situ measurements of infiltration capacity and saturated hydraulic conductivity, and laboratory analyses of soil water retention and saturated hydraulic conductivity. The irrigation experiments at the plot scale were monitored through a combination of dye tracer, salt tracer, soil moisture dynamics, and 3-D time-lapse ground penetrating radar (GPR) methods. At the hillslope scale the subsurface was explored by a 3-D GPR survey. A natural storm event and an irrigation experiment were monitored by a dense network of soil moisture observations and a cascade of 2-D time-lapse GPR trenches. We show that the shift between activated and non-activated state of the flow paths is needed to distinguish structures from overall heterogeneity. Pedo-physical analyses of point-scale samples are the basis for sub-scale structure inference. At the plot and hillslope scale 3-D and 2-D time-lapse GPR applications are successfully employed as non-invasive means to image subsurface response patterns and to identify flow-relevant paths. Tracer recovery and soil water responses from irrigation experiments deliver a consistent estimate of response velocities. The combined observation of form and function under active conditions provides the means to localize and characterize the structures (this study) and the hydrological processes (companion study Angermann et al., 2017, this issue).

  6. Structure of the active form of human origin recognition complex and its ATPase motor module

    Energy Technology Data Exchange (ETDEWEB)

    Tocilj, Ante; On, Kin Fan; Yuan, Zuanning; Sun, Jingchuan; Elkayam, Elad; Li, Huilin; Stillman, Bruce; Joshua-Tor, Leemor

    2017-01-23

    Binding of the Origin Recognition Complex (ORC) to origins of replication marks the first step in the initiation of replication of the genome in all eukaryotic cells. Here, we report the structure of the active form of human ORC determined by X-ray crystallography and cryo-electron microscopy. The complex is composed of an ORC1/4/5 motor module lobe in an organization reminiscent of the DNA polymerase clamp loader complexes. A second lobe contains the ORC2/3 subunits. The complex is organized as a double-layered shallow corkscrew, with the AAA+ and AAA+-like domains forming one layer, and the winged-helix domains (WHDs) forming a top layer. CDC6 fits easily between ORC1 and ORC2, completing the ring and the DNA-binding channel, forming an additional ATP hydrolysis site. Analysis of the ATPase activity of the complex provides a basis for understanding ORC activity as well as molecular defects observed in Meier-Gorlin Syndrome mutations.

  7. The structural bases of long-term anabiosis in non-spore-forming bacteria

    Science.gov (United States)

    Suzina, Natalia E.; Mulyukin, Andrey L.; Dmitriev, Vladimir V.; Nikolaev, Yury A.; Shorokhova, Anna P.; Bobkova, Yulia S.; Barinova, Ekaterina S.; Plakunov, Vladimir K.; El-Registan, Galina I.; Duda, Vitalii I.

    2006-01-01

    Peculiarities of the structural organization in non-spore-forming bacteria associated with long-term anabiosis were revealed both in laboratory cultures and in natural populations isolated from 1 3-Myr-old Eastern Siberian permafrost and tundra soil. Different advanced methods were used, including (a) high-resolution electron microscopy; (b) simulation of in situ conditions in the laboratory by varying the composition of growth medium and cultivation conditions; (c) low-temperature fractionation to isolate and concentrate microbial cells from natural soils; (d) comparative morphological analysis of microbial cells in model cultures and natural soils (in situ). Under laboratory conditions, the intense formation of resting cells by representatives of various taxa of eubacteria and halophilic archaea occurred in 2 9-month-old cultures grown in carbon-, nitrogen-, or phosphorus-limited media, in starved cell suspensions in the presence of sodium silicate, or on soil agar. Among resting cells, we revealed cystlike forms having a complicated structure and common features. These included a thick capsule; a thickened and multiprofile cell wall; the presence of large intramembrane particles on PF- and EF-fracture surfaces; fine-grained or lumpy cytoplasm; and a condensed nucleoid. The general morphological properties, ultrastructural organization, physiological features of cystlike cells, and their ability to germinate under the appropriate conditions suggest the existence of constitutive dormancy in non-spore-forming bacteria. It was found that the majority of microorganisms in permafrost and tundra soil are cystlike cells, very similar to those in laboratory cultures. Anabiotic (resting) cystlike cells are responsible for the survival of non-spore-formers in extreme Earth habitats and may be regarded as possible analogs of extraterrestrial forms of microbial life.

  8. Deuteron A(Q2) structure function and the neutron electric form factor

    International Nuclear Information System (INIS)

    Platchkov, S.; Amroun, A.; Auffret, S.; Cavedon, J.M.; Dreux, P.; Duclos, J.; Frois, B.; Goutte, D.; Hachemi, H.; Martino, J.

    1989-01-01

    We present new measurements of the deuteron A(Q 2 ) structure function in the momentum transfer region between 1 and 18 fm -2 . The accuracy of the data ranges from 2% to 6%. We investigate the sensitivity of A(Q 2 ) to the nucleon-nucleon interaction and to the neutron electric form factor G E n . Our analysis shows that below 20 fm -2 G E n can be inferred from these data with a significantly improved accuracy. The model dependence of this analysis is discussed

  9. Structure of the dimeric form of CTP synthase from Sulfolobus solfataricus

    DEFF Research Database (Denmark)

    Lauritsen, Iben; Willemoës, Martin; Jensen, Kaj Frank

    2011-01-01

    CTP synthase catalyzes the last committed step in de novo pyrimidine-nucleotide biosynthesis. Active CTP synthase is a tetrameric enzyme composed of a dimer of dimers. The tetramer is favoured in the presence of the substrate nucleotides ATP and UTP; when saturated with nucleotide, the tetramer...... completely dominates the oligomeric state of the enzyme. Furthermore, phosphorylation has been shown to regulate the oligomeric states of the enzymes from yeast and human. The crystal structure of a dimeric form of CTP synthase from Sulfolobus solfataricus has been determined at 2.5 Å resolution...

  10. Nucleon form factors and structure functions from Nf=2 Clover fermions

    International Nuclear Information System (INIS)

    Collins, S.; Goeckeler, M.; Haegler, P.

    2010-12-01

    We give an update on our ongoing efforts to compute the nucleon's form factors and moments of structure functions using N f =2 flavours of non-perturbatively improved Clover fermions. We focus on new results obtained on gauge configurations where the pseudo-scalar meson mass is in the range of 170-270 MeV. We compare our results with various estimates obtained from chiral effective theories since we have some overlap with the quark mass region where results from such theories are believed to be applicable. (orig.)

  11. Structure of haze forming proteins in white wines: Vitis vinifera thaumatin-like proteins.

    Science.gov (United States)

    Marangon, Matteo; Van Sluyter, Steven C; Waters, Elizabeth J; Menz, Robert I

    2014-01-01

    Grape thaumatin-like proteins (TLPs) play roles in plant-pathogen interactions and can cause protein haze in white wine unless removed prior to bottling. Different isoforms of TLPs have different hazing potential and aggregation behavior. Here we present the elucidation of the molecular structures of three grape TLPs that display different hazing potential. The three TLPs have very similar structures despite belonging to two different classes (F2/4JRU is a thaumatin-like protein while I/4L5H and H2/4MBT are VVTL1), and having different unfolding temperatures (56 vs. 62°C), with protein F2/4JRU being heat unstable and forming haze, while I/4L5H does not. These differences in properties are attributable to the conformation of a single loop and the amino acid composition of its flanking regions.

  12. The effects of topology on the structural, dynamic and mechanical properties of network-forming materials

    International Nuclear Information System (INIS)

    Wilson, Mark

    2012-01-01

    The effects of network topology on the static structural, mechanical and dynamic properties of MX 2 network-forming liquids (with tetrahedral short-range order) are discussed. The network topology is controlled via a single model parameter (the anion polarizability) which effectively constrains the inter-tetrahedral linkages in a physically transparent manner. Critically, it is found to control the balance between the stability of corner- and edge-sharing tetrahedra. A potential rigidity transformation is investigated. The vibrational density of states is investigated, using an instantaneous normal model analysis, as a function of both anion polarizability and temperature. A low frequency peak is seen to appear and is shown to be correlated with the fraction of cations which are linked through solely edge-sharing structural motifs. A modified effective mean atom coordination number is proposed which allows the appearance of the low frequency feature to be understood in terms of a mean field rigidity percolation threshold. (paper)

  13. Structural features of anodic oxide films formed on aluminum substrate coated with self-assembled microspheres

    International Nuclear Information System (INIS)

    Asoh, Hidetaka; Uchibori, Kota; Ono, Sachiko

    2009-01-01

    The structural features of anodic oxide films formed on an aluminum substrate coated with self-assembled microspheres were investigated by scanning electron microscopy and atomic force microscopy. In the first anodization in neutral solution, the growth of a barrier-type film was partially suppressed in the contact area between the spheres and the underlying aluminum substrate, resulting in the formation of ordered dimple arrays in an anodic oxide film. After the subsequent second anodization in acid solution at a voltage lower than that of the first anodization, nanopores were generated only within each dimple. The nanoporous region could be removed selectively by post-chemical etching using the difference in structural dimensions between the porous region and the surrounding barrier region. The mechanism of anodic oxide growth on the aluminum substrate coated with microspheres through multistep anodization is discussed.

  14. Structural features of anodic oxide films formed on aluminum substrate coated with self-assembled microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Asoh, Hidetaka [Department of Applied Chemistry, Faculty of Engineering, Kogakuin University, 2665-1 Nakano, Hachioji, Tokyo 192-0015 (Japan)], E-mail: asoh@cc.kogakuin.ac.jp; Uchibori, Kota; Ono, Sachiko [Department of Applied Chemistry, Faculty of Engineering, Kogakuin University, 2665-1 Nakano, Hachioji, Tokyo 192-0015 (Japan)

    2009-07-15

    The structural features of anodic oxide films formed on an aluminum substrate coated with self-assembled microspheres were investigated by scanning electron microscopy and atomic force microscopy. In the first anodization in neutral solution, the growth of a barrier-type film was partially suppressed in the contact area between the spheres and the underlying aluminum substrate, resulting in the formation of ordered dimple arrays in an anodic oxide film. After the subsequent second anodization in acid solution at a voltage lower than that of the first anodization, nanopores were generated only within each dimple. The nanoporous region could be removed selectively by post-chemical etching using the difference in structural dimensions between the porous region and the surrounding barrier region. The mechanism of anodic oxide growth on the aluminum substrate coated with microspheres through multistep anodization is discussed.

  15. REMOTE WORK AS A PROMISING FORM OF LABOUR ORGANIZATION FOR RUSSIAN ENTREPRENEURIAL STRUCTURES

    Directory of Open Access Journals (Sweden)

    I. Gurova

    2016-01-01

    Full Text Available Remote work (telecommuting is one of the modern technologies of the organization of the labor process, which is not yet widely used in domestic practice. However, in times of crisis, when entrepreneurial structures seek for the maximum reduction of expenses, it can be a tool to address many of the pressing issues related to the most effective use of production and labor resources.The article discusses the features of the remote work on a world level and in our country, detected its strengths and weaknesses for the participants of labour relations, as well as revealed the potential of this form of labor organization for achievement of optimum balance between expenses and efficiency of entrepreneurial structures.

  16. Nur77 forms novel nuclear structures upon DNA damage that cause transcriptional arrest

    International Nuclear Information System (INIS)

    Leseleuc, Louis de; Denis, Francois

    2006-01-01

    The orphan nuclear receptor Nur77 has been implicated in both growth and apoptosis, and its function and activity can be modulated by cellular redistribution. Green fluorescent protein-tagged Nur77 was used to evaluate the role of Nur77 intracellular redistribution in response to genotoxic stress. Selected DNA damaging agents and transcription inhibition lead to rapid redistribution of Nur77 into nuclear structures distinct from conventional nuclear bodies. These nuclear bodies formed transiently were tightly bound to the nuclear matrix and conditions that lead to their appearance were associated with Nur77 transcriptional inhibition. The formation of Nur77 nuclear bodies might be involved in programmed cell death modulation upon exposure to DNA damaging agents that inhibit transcription by sequestrating this proapoptotic factor in dense nuclear structures

  17. Structure of haze forming proteins in white wines: Vitis vinifera thaumatin-like proteins.

    Directory of Open Access Journals (Sweden)

    Matteo Marangon

    Full Text Available Grape thaumatin-like proteins (TLPs play roles in plant-pathogen interactions and can cause protein haze in white wine unless removed prior to bottling. Different isoforms of TLPs have different hazing potential and aggregation behavior. Here we present the elucidation of the molecular structures of three grape TLPs that display different hazing potential. The three TLPs have very similar structures despite belonging to two different classes (F2/4JRU is a thaumatin-like protein while I/4L5H and H2/4MBT are VVTL1, and having different unfolding temperatures (56 vs. 62°C, with protein F2/4JRU being heat unstable and forming haze, while I/4L5H does not. These differences in properties are attributable to the conformation of a single loop and the amino acid composition of its flanking regions.

  18. Distinct atomic structures of the Ni-Nb metallic glasses formed by ion beam mixing

    International Nuclear Information System (INIS)

    Tai, K. P.; Wang, L. T.; Liu, B. X.

    2007-01-01

    Four Ni-Nb metallic glasses are obtained by ion beam mixing and their compositions are measured to be Ni 77 Nb 23 , Ni 55 Nb 45 , Ni 31 Nb 69 , and Ni 15 Nb 85 , respectively, suggesting that a composition range of 23-85 at. % of Nb is favored for metallic glass formation in the Ni-Nb system. Interestingly, diffraction analyses show that the structure of the Nb-based Ni 31 Nb 69 metallic glass is distinctly different from the structure of the Nb-based Ni 15 Nb 85 metallic glass, as the respective amorphous halos are located at 2θ≅38 and 39 deg. To explore an atomic scale description of the Ni-Nb metallic glasses, an n-body Ni-Nb potential is first constructed with an aid of the ab initio calculations and then applied to perform the molecular dynamics simulation. Simulation results determine not only the intrinsic glass forming range of the Ni-Nb system to be within 20-85 at. % of Nb, but also the exact atomic positions in the Ni-Nb metallic glasses. Through a statistical analysis of the determined atomic positions, a new dominant local packing unit is found in the Ni 15 Nb 85 metallic glass, i.e., an icositetrahedron with a coordination number to be around 14, while in Ni 31 Nb 69 metallic glasses, the dominant local packing unit is an icosahedron with a coordination number to be around 12, which has been reported for the other metallic glasses. In fact, with increasing the irradiation dose, the Ni 31 Nb 69 metallic glasses are formed through an intermediate state of face-centered-cubic-solid solution, whereas the Ni 15 Nb 85 metallic glass is through an intermediate state of body-centered-cubic-solid solution, suggesting that the structures of the constituent metals play an important role in governing the structural characteristics of the resultant metallic glasses

  19. Isolation and structural elucidation of tiamulin metabolites formed in liver microsomes of pigs.

    Science.gov (United States)

    Lykkeberg, Anne Kruse; Cornett, Claus; Halling-Sørensen, Bent; Hansen, Steen Honoré

    2006-09-18

    Although the antimicrobial tiamulin is extensively metabolized in pigs, the metabolism is not well investigated. In this work the NADPH dependent metabolism of tiamulin in liver microsomes from pigs has been studied. The tiamulin metabolites formed in the incubations were analysed using LC-MS, and three major metabolites were isolated using solid phase extraction and preparative HPLC. The final structure elucidations were performed by tandem mass spectrometry and (1)H and (13)C NMR. The structures of the metabolites were found to be 2beta-hydroxy-tiamulin, 8alpha-hydroxy-tiamulin and N-deethyl-tiamulin. In addition, the LC-MS chromatograms revealed two other minor metabolites. From their chromatography and from MS(2) analysis the structures were estimated to be 2beta-hydroxy-N-deethyl-tiamulin and 8alpha-hydroxy-N-deethyl-tiamulin, but the structures were not confirmed by NMR. In these studies approximately 20% of tiamulin was deethylated, 10% was hydroxylated in the 2beta-position and 7% was hydroxylated in the 8alpha-position. About 40% of tiamulin was metabolized during the incubation conditions used. The protein precipitation in the incubations was performed using perchloric acid, and the preparative purification was performed under alkaline conditions. Therefore, the stability of the metabolites under these conditions was studied. The metabolites were found to be stable in the acid solution, but under alkaline conditions, particularly at room temperature, the stability of especially 8alpha-hydroxy-tiamulin was considerably reduced (40% loss after 1 week).

  20. Structural predictor for nonlinear sheared dynamics in simple glass-forming liquids.

    Science.gov (United States)

    Ingebrigtsen, Trond S; Tanaka, Hajime

    2018-01-02

    Glass-forming liquids subjected to sufficiently strong shear universally exhibit striking nonlinear behavior; for example, a power-law decrease of the viscosity with increasing shear rate. This phenomenon has attracted considerable attention over the years from both fundamental and applicational viewpoints. However, the out-of-equilibrium and nonlinear nature of sheared fluids have made theoretical understanding of this phenomenon very challenging and thus slower to progress. We find here that the structural relaxation time as a function of the two-body excess entropy, calculated for the extensional axis of the shear flow, collapses onto the corresponding equilibrium curve for a wide range of pair potentials ranging from harsh repulsive to soft and finite. This two-body excess entropy collapse provides a powerful approach to predicting the dynamics of nonequilibrium liquids from their equilibrium counterparts. Furthermore, the two-body excess entropy scaling suggests that sheared dynamics is controlled purely by the liquid structure captured in the form of the two-body excess entropy along the extensional direction, shedding light on the perplexing mechanism behind shear thinning.

  1. Structural predictor for nonlinear sheared dynamics in simple glass-forming liquids

    Science.gov (United States)

    Ingebrigtsen, Trond S.; Tanaka, Hajime

    2018-01-01

    Glass-forming liquids subjected to sufficiently strong shear universally exhibit striking nonlinear behavior; for example, a power-law decrease of the viscosity with increasing shear rate. This phenomenon has attracted considerable attention over the years from both fundamental and applicational viewpoints. However, the out-of-equilibrium and nonlinear nature of sheared fluids have made theoretical understanding of this phenomenon very challenging and thus slower to progress. We find here that the structural relaxation time as a function of the two-body excess entropy, calculated for the extensional axis of the shear flow, collapses onto the corresponding equilibrium curve for a wide range of pair potentials ranging from harsh repulsive to soft and finite. This two-body excess entropy collapse provides a powerful approach to predicting the dynamics of nonequilibrium liquids from their equilibrium counterparts. Furthermore, the two-body excess entropy scaling suggests that sheared dynamics is controlled purely by the liquid structure captured in the form of the two-body excess entropy along the extensional direction, shedding light on the perplexing mechanism behind shear thinning.

  2. Optimizing structure of complex technical system by heterogeneous vector criterion in interval form

    Science.gov (United States)

    Lysenko, A. V.; Kochegarov, I. I.; Yurkov, N. K.; Grishko, A. K.

    2018-05-01

    The article examines the methods of development and multi-criteria choice of the preferred structural variant of the complex technical system at the early stages of its life cycle in the absence of sufficient knowledge of parameters and variables for optimizing this structure. The suggested methods takes into consideration the various fuzzy input data connected with the heterogeneous quality criteria of the designed system and the parameters set by their variation range. The suggested approach is based on the complex use of methods of interval analysis, fuzzy sets theory, and the decision-making theory. As a result, the method for normalizing heterogeneous quality criteria has been developed on the basis of establishing preference relations in the interval form. The method of building preferential relations in the interval form on the basis of the vector of heterogeneous quality criteria suggest the use of membership functions instead of the coefficients considering the criteria value. The former show the degree of proximity of the realization of the designed system to the efficient or Pareto optimal variants. The study analyzes the example of choosing the optimal variant for the complex system using heterogeneous quality criteria.

  3. Diverse supramolecular structures formed by self‐assembling proteins of the B acillus subtilis spore coat

    Science.gov (United States)

    Jiang, Shuo; Wan, Qiang; Krajcikova, Daniela; Tang, Jilin; Tzokov, Svetomir B.; Barak, Imrich

    2015-01-01

    Summary Bacterial spores (endospores), such as those of the pathogens C lostridium difficile and B acillus anthracis, are uniquely stable cell forms, highly resistant to harsh environmental insults. B acillus subtilis is the best studied spore‐former and we have used it to address the question of how the spore coat is assembled from multiple components to form a robust, protective superstructure. B . subtilis coat proteins (CotY, CotE, CotV and CotW) expressed in E scherichia coli can arrange intracellularly into highly stable macro‐structures through processes of self‐assembly. Using electron microscopy, we demonstrate the capacity of these proteins to generate ordered one‐dimensional fibres, two‐dimensional sheets and three‐dimensional stacks. In one case (CotY), the high degree of order favours strong, cooperative intracellular disulfide cross‐linking. Assemblies of this kind could form exquisitely adapted building blocks for higher‐order assembly across all spore‐formers. These physically robust arrayed units could also have novel applications in nano‐biotechnology processes. PMID:25872412

  4. Heterogeneous Seeding of a Prion Structure by a Generic Amyloid Form of the Fungal Prion-forming Domain HET-s(218-289)

    Energy Technology Data Exchange (ETDEWEB)

    Wan, William; Bian, Wen; McDonald, Michele; Kijac, Aleksandra; Wemmer, David E.; Stubbs, Gerald [UCB; (Vanderbilt); (LBNL)

    2013-11-13

    The fungal prion-forming domain HET-s(218–289) forms infectious amyloid fibrils at physiological pH that were shown by solid-state NMR to be assemblies of a two-rung β-solenoid structure. Under acidic conditions, HET-s(218–289) has been shown to form amyloid fibrils that have very low infectivity in vivo, but structural information about these fibrils has been very limited. We show by x-ray fiber diffraction that the HET-s(218–289) fibrils formed under acidic conditions have a stacked β-sheet architecture commonly found in short amyloidogenic peptides and denatured protein aggregates. At physiological pH, stacked β-sheet fibrils nucleate the formation of the infectious β-solenoid prions in a process of heterogeneous seeding, but do so with kinetic profiles distinct from those of spontaneous or homogeneous (seeded with infectious β-solenoid fibrils) fibrillization. Several serial passages of stacked β-sheet-seeded solutions lead to fibrillization kinetics similar to homogeneously seeded solutions. Our results directly show that structural mutation can occur between substantially different amyloid architectures, lending credence to the suggestion that the processes of strain adaptation and crossing species barriers are facilitated by structural mutation.

  5. Unique hyper-thermal composting process in Kagoshima City forms distinct bacterial community structures.

    Science.gov (United States)

    Tashiro, Yukihiro; Tabata, Hanae; Itahara, Asuka; Shimizu, Natsuki; Tashiro, Kosuke; Sakai, Kenji

    2016-11-01

    A unique compost, Satsuma soil, is produced from three types of wastewater sludge using hyper-thermal processes at temperatures much higher than that of general thermophilic processes in Kagoshima City, Japan. We analyzed the bacterial community structures of this hyper-thermal compost sample and other sludges and composts by a high-throughput barcoded pyrosequencing method targeting the 16S rRNA gene. In total, 621,076 reads were derived from 17 samples and filtered. Artificial sequences were deleted and the reads were clustered based on the operational taxonomic units (OTUs) at 97% similarity. Phylum-level analysis of the hyper-thermal compost revealed drastic changes of the sludge structures (each relative abundance) from Firmicutes (average 47.8%), Proteobacteria (average 22.3%), and Bacteroidetes (average 10.1%) to two main phyla including Firmicutes (73.6%) and Actinobacteria (25.0%) with less Proteobacteria (∼0.3%) and Bacteroidetes (∼0.1%). Furthermore, we determined the predominant species (each relative abundance) of the hyper-thermal compost including Firmicutes related to Staphylococcus cohnii (13.8%), Jeotgalicoccus coquinae (8.01%), and Staphylococcus lentus (5.96%), and Actinobacteria related to Corynebacterium stationis (6.41%), and found that these species were not predominant in wastewater sludge. In contrast, we did not observe any common structures among eight other composts produced, using the hyper-thermal composts as the inoculums, under thermophilic conditions from different materials. Principle coordinate analysis of the hyper-thermal compost indicated a large difference in bacterial community structures from material sludge and other composts. These results suggested that a distinct bacterial community structure was formed by hyper-thermal composting. Copyright © 2016 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  6. Composition and molecular scale structure of nanophases formed by precipitation of biotite weathering products

    Science.gov (United States)

    Tamrat, Wuhib Zewde; Rose, Jérôme; Grauby, Olivier; Doelsch, Emmanuel; Levard, Clément; Chaurand, Perrine; Basile-Doelsch, Isabelle

    2018-05-01

    Because of their large surface area and reactivity, nanometric-size soil mineral phases have a high potential for soil organic matter stabilization, contaminant sorption or soil aggregation. In the literature, Fe and Al phases have been the main targets of batch-synthesized nanomineral studies while nano-aluminosilicates (Al and Si phases) have been mainly studied in Andic soils. In the present work, we synthesized secondary nanophases of Fe, Al and Si. To simulate a system as close as possible to soil conditions, we conducted laboratory simulations of the processes of (1) biotite alteration in acidic conditions producing a Al Si Fe Mg K leachate solution and (2) the following neoformation of secondary nanophases by titrating the leachate solution to pH 4.2, 5 and 7. The morphology of the nanophases, their size, crystallinity and chemistry were characterized by TEM-EDX on single particles and their local atomic structure by EXAFS (Extended X-ray Absorption Fine Structure) at the Fe absorption K-edge. The main nanophases formed were amorphous particles 10-60 nm in size whose composition (dominated by Fe and Si) was strongly controlled by the pH conditions at the end of the titration. At pH 4.2 and pH 7, the structure of the nanophases was dominated by the polymerization of Fe, which was hindered by Al, Si, Mg and K. Conversely, at pH 5, the polymerization of Fe was counteracted by precipitation of high amounts of Si. The synthetized nanophases were estimated to be rather analogous to nanophases formed in natural biotite-bearing soils. Because of their small size and potential high surface reactivity, the adsorption capacities of these nanophases with respect to the OM should be revisited in the framework of soil C storage.

  7. Crystalline structure of the marketed form of Rifampicin: a case of conformational and charge transfer polymorphism

    Science.gov (United States)

    de Pinho Pessoa Nogueira, Luciana; de Oliveira, Yara S.; de C. Fonseca, Jéssica; Costa, Wendell S.; Raffin, Fernanda N.; Ellena, Javier; Ayala, Alejandro Pedro

    2018-03-01

    Rifampicin is a semi-synthetic drug derived from rifamycin B, and currently integrates the fixed dose combination tablet formulations used in the treatment of tuberculosis. It is also used in the leprosy polychemotherapy and prophylaxis, which are diseases classified as neglected according to the World Health Organization. Rifampicin is a polymorphic drug and its desirable polymorphic form is labeled as II, being the main goal of this study the elucidation of its crystalline structure. Polymorph II is characterized by two molecules with different conformations in the asymmetric unit and the following lattice parameters: a = 14.0760 (10) Å, b = 17.5450 (10) Å, c = 17.5270 (10) Å, β = 92.15°. Differently to the previously reported structures, a charge transference from the hydroxyl group of the naphthoquinone of one conformer to the nitrogen of the piperazine group of the second conformer was observed. The relevance of the knowledge of this crystalline structure, which is the preferred polymorph for pharmaceutical formulations, was evidenced by analyzing raw materials with polymorphic mixtures. Thus, the results presented in this contribution close an old information gap allowing the complete solid-state characterization of rifampicin.

  8. ASSESSMENT FORM - NEW IMPROVEMENT OF ACTIONS: CONCENTRATION AND RESEARCH AREAS / CURRICULUM STRUCTURE / FUNDRAISING

    Directory of Open Access Journals (Sweden)

    Iracema MP Calderon

    Full Text Available Objective: This review aims to develop a critical and current analysis of the basic structure of a Postgraduate program for proposing improvement actions and new evaluation criteria. Method: To examine the items that are areas of concentration (AC, research lines (LP, research projects (PP, curricular structure and fundraising were consulted the Area Document, the 2013 Evaluation Report and the Assessment Sheets of Medicine III programs, evaluated in the 2010-2012 period. Results: Consistency is recommended especially among AC, LP and PP, with genuine link between activities and permanent teachers skills and based on structured curriculum in the education of the student. The Program Proposal interfere, and much, in qualifying a program. The curriculum should provide subsidy to the formation of the researcher, through the core subjects, and development of PP, being the concept of disciplines to support lines and research projects. Fundraise should be set out in research projects and in the CV-Lattes. The area recommended that at least 40-50% of permanent teachers present fundraising and the minimum 20-25% of these teachers to have productivity scholarship PQ / CNPq during the triennium. Conclusion: It is necessary to promote wide discussion and find a consensus denominator for these issues. The actions should contribute to the improvement of evaluation forms and certainly for the qualification of the programs but graduate.

  9. Cavitation structures formed during the rebound of a sphere from a wetted surface

    KAUST Repository

    Marston, Jeremy; Wang, Yong; Ng, Waikiong; Tan, Reginald; Thoroddsen, Sigurdur T

    2010-01-01

    We use high-speed imaging to observe the dynamics of cavitation, caused by the impact and subsequent rebound of a sphere from a solid surface covered with a thin layer of highly viscous liquid. We note marked qualitative differences between the cavitation structures with increase in viscosity, as well as between Newtonian and non-Newtonian liquids. The patterns observed are quite unexpected and intricate, appearing in concentric ring formations around the site of impact. In all cases, we identify a distinct radius from which the primary bubbles emanate. This radius is modelled with a modified form of Hertz contact theory. Within this radius, we show that some fine cavitation structure may exist or that it may be one large cavitation bubble. For the non-Newtonian fluids, we observe foam-like structures extending radially with diminishing bubble sizes with increase in radial position. Whereas for the Newtonian fluids, the opposite trend is observed with increasing bubble size for increasing radial position. Finally, we compare our experimental observations of cavitation to the maximum tension criterion proposed by Joseph (J Fluid Mech 366:367-378, 1998) showing that this provides the lower limit for the onset of cavitation in our experiments. © 2010 Springer-Verlag.

  10. Cavitation structures formed during the rebound of a sphere from a wetted surface

    KAUST Repository

    Marston, Jeremy

    2010-09-28

    We use high-speed imaging to observe the dynamics of cavitation, caused by the impact and subsequent rebound of a sphere from a solid surface covered with a thin layer of highly viscous liquid. We note marked qualitative differences between the cavitation structures with increase in viscosity, as well as between Newtonian and non-Newtonian liquids. The patterns observed are quite unexpected and intricate, appearing in concentric ring formations around the site of impact. In all cases, we identify a distinct radius from which the primary bubbles emanate. This radius is modelled with a modified form of Hertz contact theory. Within this radius, we show that some fine cavitation structure may exist or that it may be one large cavitation bubble. For the non-Newtonian fluids, we observe foam-like structures extending radially with diminishing bubble sizes with increase in radial position. Whereas for the Newtonian fluids, the opposite trend is observed with increasing bubble size for increasing radial position. Finally, we compare our experimental observations of cavitation to the maximum tension criterion proposed by Joseph (J Fluid Mech 366:367-378, 1998) showing that this provides the lower limit for the onset of cavitation in our experiments. © 2010 Springer-Verlag.

  11. Resilin and chitinous cuticle form a composite structure for energy storage in jumping by froghopper insects

    Directory of Open Access Journals (Sweden)

    Shaw Stephen R

    2008-09-01

    Full Text Available Abstract Background Many insects jump by storing and releasing energy in elastic structures within their bodies. This allows them to release large amounts of energy in a very short time to jump at very high speeds. The fastest of the insect jumpers, the froghopper, uses a catapult-like elastic mechanism to achieve their jumping prowess in which energy, generated by the slow contraction of muscles, is released suddenly to power rapid and synchronous movements of the hind legs. How is this energy stored? Results The hind coxae of the froghopper are linked to the hinges of the ipsilateral hind wings by pleural arches, complex bow-shaped internal skeletal structures. They are built of chitinous cuticle and the rubber-like protein, resilin, which fluoresces bright blue when illuminated with ultra-violet light. The ventral and posterior end of this fluorescent region forms the thoracic part of the pivot with a hind coxa. No other structures in the thorax or hind legs show this blue fluorescence and it is not found in larvae which do not jump. Stimulating one trochanteral depressor muscle in a pattern that simulates its normal action, results in a distortion and forward movement of the posterior part of a pleural arch by 40 μm, but in natural jumping, the movement is at least 100 μm. Conclusion Calculations showed that the resilin itself could only store 1% to 2% of the energy required for jumping. The stiffer cuticular parts of the pleural arches could, however, easily meet all the energy storage needs. The composite structure therefore, combines the stiffness of the chitinous cuticle with the elasticity of resilin. Muscle contractions bend the chitinous cuticle with little deformation and therefore, store the energy needed for jumping, while the resilin rapidly returns its stored energy and thus restores the body to its original shape after a jump and allows repeated jumping.

  12. An Examination of the Structure of the Career Decision Self-Efficacy Scale (Short Form) among Italian High School Students

    Science.gov (United States)

    Presti, Alessandro Lo; Pace, Francesco; Mondo, Marina; Nota, Laura; Casarubia, Provvidenza; Ferrari, Lea; Betz, Nancy E.

    2013-01-01

    This study aims to evaluate the factor structure of Career Decision Self-Efficacy scale-short form in a sample of Italian high school adolescents. confirmatory factor analysis (CFA) was used to test the degree to which a one-factor structure and a five-factor structure provided the best fit. In view of available research the five-factor structure…

  13. Forming a structure of the CoNiFe alloys by X-ray irradiation

    Science.gov (United States)

    Valko, Natalia; Kasperovich, Andrey; Koltunowicz, Tomasz N.

    The experimental data of electrodeposition kinetics researches and structure formation of ternary CoNiFe alloys deposited onto low-carbon steel 08kp in the presence of X-rays are presented. Relations of deposit rate, current efficiencies, element and phase compositions of CoNiFe coatings formed from sulfate baths with respect to cathode current densities (0.5-3A/dm2), electrolyte composition and irradiation were obtained. It is shown that, the CoNiFe coatings deposited by the electrochemical method involving exposure of the X-rays are characterized by more perfect morphology surfaces with less developed surface geometry than reference coatings. The effect of the X-ray irradiation on the electrodeposition of CoNiFe coatings promotes formatting of alloys with increased electropositive component and modified phase composition.

  14. Evaluation of five years of nursing home inspection forms: structural and hygiene-related violation trends.

    Science.gov (United States)

    Avery, Chris; Humphrey, Charles; Balany, Jo Anne

    2014-11-01

    Health inspections are performed at nursing homes to identify and reduce risk and to help maintain a safe environment for nursing home residents. The study described in this article aimed to identify the most frequent violations, types of violations (hygiene or structural), and repeat violations in nursing home facilities during health inspections; and to determine if the age of the facility influenced inspection scores. Nursing home health inspection forms (N = 131) completed between 2005 and 2011 in Pitt County, North Carolina, were analyzed. Results indicated that 60% of all violations were hygiene-related and could possibly be corrected without significant financial investments by management. Significant correlations occurred between the total number of violations and the facility age (p = .003) and between the number of repeat violations and total violations (p < .001). The average inspection score for nursing homes could be increased by more than three points if sanitation practices were improved.

  15. Structure of zinc particles formed by condensation for transportation to an analytic device

    Energy Technology Data Exchange (ETDEWEB)

    Barone, T.; Wochele, J.; Ludwig, C.; Schuler, A.J.; Ketterer, B.

    2002-03-01

    Aerosol containing small particles with homogeneous structural characteristics are desired for analysis in Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES). To investigate heavy metal evaporation behaviour during thermal treatment a laboratory on-line elemental analyzer has been developed. The analyzer consists of a Condensation Interface (CI) for the generation of aerosols and an ICP-OES as detector. The settings at the CI can strongly influence the particle formation, and therefore the quality of the measurements. To improve the method preliminary experiments were conducted to investigate the characteristics of zinc particles formed in the evaporation/condensation process. System conditions, such as vaporization temperature, carrier gas, and flow rate, were varied to investigate their influence on particle size, homogeneity and shape. The experiments suggest that particles vary most with temperature, lower vaporization temperatures resulted in the formation of smaller particles. (author)

  16. Field-aligned plasma-potential structure formed by local electron cyclotron resonance

    International Nuclear Information System (INIS)

    Hatakeyama, Rikizo; Kaneko, Toshiro; Sato, Noriyoshi

    2001-01-01

    The significance of basic experiments on field-aligned plasma-potential structure formed by local electron cyclotron resonance (ECR) is claimed based on the historical development of the investigation on electric double layer and electrostatic potential confinement of open-ended fusion-oriented plasmas. In the presence of a single ECR point in simple mirror-type configurations of magnetic field, a potential dip (thermal barrier) appears around this point, being followed by a subsequent potential hump (plug potential) along a collisionless plasma flow. The observed phenomenon gives a clear-cut physics to the formation of field-aligned plug potential with thermal barrier, which is closely related to the double layer formation triggered by a negative dip. (author)

  17. Structural investigation of the spinel phase formed in fuel CRUD before and after zinc injection

    International Nuclear Information System (INIS)

    Chen, J.

    2002-01-01

    Spinel phase is an important constituent of fuel CRUD. Since it can accommodate 60 Co in its crystal structure, its stability in reactor water environment is crucial for the radioactivity control in LWR plants. With increasing curiosity about zinc injection technology, the mechanism of the interaction of zinc with the spinel has drawn much attention. This paper describes the crystal and microstructures of spinel phase in the fuel CRUD collected on four fuel rods of 1- and 5-cycle, respectively, from Barsebaeck 2 BWR before and after zinc injection operation. High precision X-ray powder diffraction technique has been applied to identify the phase compositions of fuel CRUD and to measure the cell length of the spinel phase formed. The results show that, after about 1-cycle zinc injection operation, the tenacious CRUD formed on the fresh fuel rod contains defective zinc oxide, in addition to hematite and spinel as commonly seen. Moreover, the phase ratio of spinel to hematite is much increased. The cell length of the spinel is increased accordingly, which is the direct evidence for the presence of zinc in the spinel structure. For the 5-cycle rod, however, neither zinc oxide nor any change in the phase ratio has been detected. The cell length of the spinel has been increased, in a less degree, however, as compared to that for the 1-cycle rod. The cell lengths of spinel are similar in both tenacious and loose CRUD layers, indicating that zinc was able to easily penetrate through the tenacious CRUD layer. (authors)

  18. The Structure of the Nearby Giant Star-Forming Region 30 Doradus

    Science.gov (United States)

    Pellegrini, Eric; Baldwin, Jack; Hanson, Margaret; Ferland, Gary; Troland, Thomas

    2007-08-01

    The rates of star formation and chemical evolution are controlled in part by the interaction of stellar radiation and winds with the remnant molecular gas from which the stars have formed. We are carrying out a detailed, panchromatic study of these processes in the two nearest giant star-forming regions, 30 Doradus and NGC 3603, as an aide in understanding the nature of Giant Extragalactic H II Regions, starbursts, and Ultra-Luminous IR Galaxies. We recently completed our observations of NGC 3603. Here we request 2 nights on the Blanco telescope to obtain a dense grid of optical long-slit spectra criss- crossing 30 Dor. These will cover the [S II] doublet (to measure N_e) and also [O III], H(beta), [O I], H(alpha) and [N II] to measure the ionization mechanism and ionization parameter, at ~3800 different spots in the nebula. We also request 3 nights on SOAR to take K-band long slit spectra covering H^+ Br(gamma) and several H_2 lines across three representative edge-on ionization fronts in 30 Dor. The IR spectra will be taken in locations also covered by the optical spectra, and will tell us about the structure, pressure support and heating mechanisms in the photo-dissociation regions (PDRs) at these points. Either half of this project can stand on its own, but both parts together will permit the PI to complete his PhD thesis.

  19. Structure of a hexameric form of RadA recombinase from Methanococcus voltae

    International Nuclear Information System (INIS)

    Du, Liqin; Luo, Yu

    2012-01-01

    Hexameric rings of RadA recombinase from M. voltae have been crystallized. Structural comparisons suggest that homologues of RadA tend to form double-ringed assemblies. Archaeal RadA proteins are close homologues of eukaryal Rad51 and DMC1 proteins and are remote homologues of bacterial RecA proteins. For the repair of double-stranded breaks in DNA, these recombinases promote a pivotal strand-exchange reaction between homologous single-stranded and double-stranded DNA substrates. This DNA-repair function also plays a key role in the resistance of cancer cells to chemotherapy and radiotherapy and in the resistance of bacterial cells to antibiotics. A hexameric form of a truncated Methanococcus voltae RadA protein devoid of its small N-terminal domain has been crystallized. The RadA hexamers further assemble into two-ringed assemblies. Similar assemblies can be observed in the crystals of Pyrococcus furiosus RadA and Homo sapiens DMC1. In all of these two-ringed assemblies the DNA-interacting L1 region of each protomer points inward towards the centre, creating a highly positively charged locus. The electrostatic characteristics of the central channels can be utilized in the design of novel recombinase inhibitors

  20. The use of quadratic forms in the calculation of ground state electronic structures

    International Nuclear Information System (INIS)

    Keller, Jaime; Weinberger, Peter

    2006-01-01

    There are many examples in theoretical physics where a fundamental quantity can be considered a quadratic form ρ=Σ i ρ i =vertical bar Ψ vertical bar 2 and the corresponding linear form Ψ=Σ i ψ i is highly relevant for the physical problem under study. This, in particular, is the case of the density and the wave function in quantum mechanics. In the study of N-identical-fermion systems we have the additional feature that Ψ is a function of the 3N configuration space coordinates and ρ is defined in three-dimensional real space. For many-electron systems in the ground state the wave function and the Hamiltonian are to be expressed in terms of the configuration space (CS), a replica of real space for each electron. Here we present a geometric formulation of the CS, of the wave function, of the density, and of the Hamiltonian to compute the electronic structure of the system. Then, using the new geometric notation and the indistinguishability and equivalence of the electrons, we obtain an alternative computational method for the ground state of the system. We present the method and discuss its usefulness and relation to other approaches

  1. Phytosterol Profiles of Common Foods and Estimated Natural Intake of Different Structures and Forms in China.

    Science.gov (United States)

    Wang, Mengmeng; Huang, Weisu; Hu, Yinzhou; Zhang, Liangxiao; Shao, Yafang; Wang, Meng; Zhang, Fang; Zhao, Ziyan; Mei, Xiaohong; Li, Tao; Wang, Donghui; Liang, Ying; Li, Jing; Huang, Yining; Zhang, Liuquan; Xu, Tao; Song, Huaxin; Zhong, Yongheng; Lu, Baiyi

    2018-03-21

    Phytosterols are well-known for their cholesterol-lowering effects, and the structures and forms of phytosterols affect their bioactivity. We aimed to illustrate the phytosterol profiles in common foods and estimate their natural intake in five geographical regions and among different age groups in China. In total, 12 phytosterols in free and esterified forms of 119 foods from five regions across China were examined using gas chromatography-mass spectrometry. Then, the dietary intake of phytosterols was calculated combined with the dietary foods intake data of Chinese people. The total phytosterol content was highest in vegetable oils (150.4-1230.9 mg/100 g), followed by legumes (129.6-275.6 mg/100 g), nuts (18.9-255.2 mg/100 g), and cereals (11.9-93.8 mg/100 g). Vegetables and fruits contained lower contents of total phytosterols. Phytosterols were mainly esterified in most common foods except in nuts. The predominant phytosterols were β-sitosterol, campesterol, and stigmasterol, all of which belonged to plant sterols and 4-desmethylsterols. Total phytosterol intake varied across different regions, ranging between 257.7 and 473.7 mg/standard-person (sp)/day, with the highest intake in Beijing, followed by Hangzhou, Wuhan, Chongqing, and Guangzhou. However, phytosterol proportion was similar across regions, with β-sitosterol accounting for 46.5-50.3% of the natural intake. Phytosterol intake was mainly constituted by plant sterols and 4-desmethylsterols in esterified form (61.9-74.6%). At the age of 2-70 years, phytosterol intake ranged from 154.3 mg/day to 348.0 mg/day in the national scale.

  2. Structured printed referral letter (form letter; saves time and improves communication

    Directory of Open Access Journals (Sweden)

    R.P.J.C. Ramanayake

    2013-01-01

    Full Text Available Referral of patients to hospitals, specialists and other institutions is an essential part of primary health care. Patients are referred to specialists when investigation or therapeutic options are exhausted in primary care or when opinion or advice is needed from them. Referral has considerable implications for patients, health care system and health care costs. Good communication between primary and secondary care is essential for the smooth running of any health care system. Referral and reply letters are the sole means of communication between doctors most of the time and breakdown in communication could lead to poor continuity of care, delayed diagnoses, polypharmacy, increased litigation risk and unnecessary testing. A referral letter also helps to avoid patient dissatisfaction and loss of confidence in family physician. Studies of referral letters have reported that specialists are dissatisfied with their quality and content. Inclusion of letter writing skills in the medical curriculum, peer assessment and feedback have shown to improve the quality of referral letters. . Form letters have shown to enhance information content and communication in referral process. In Sri Lanka referral letters are usually hand written and frequent complaints are that these letters do not contain adequate information and retrieval of information is a problem due to poor legibility and clarity. Sometimes Primary care doctors refer patients to hospitals and specialists with only verbal instructions. To address these short comings this form letter was introduced. Based on the guidelines and systematic review of published articles, items of information to be included were decided. Printed forms of the letter are kept in the practice and the doctor has to just fill up relevant information under each heading. The objectives of introducing this structured referral letter was to improve the quality and standard of referral letters and save time for both general

  3. The plant economics spectrum is structured by leaf habits and growth forms across subtropical species.

    Science.gov (United States)

    Zhao, Yan-Tao; Ali, Arshad; Yan, En-Rong

    2017-02-01

    The plant economics spectrum that integrates the combination of leaf and wood syndromes provides a useful framework for the examination of species strategies at the whole-plant level. However, it remains unclear how species that differ in leaf habits and growth forms are integrated within the plant economics spectrum in subtropical forests. We measured five leaf and six wood traits across 58 subtropical plant species, which represented two leaf habits (evergreen vs deciduous) and two growth forms (tree vs shrub) in eastern China. Principal component analysis (PCA) was employed separately to construct the leaf (LES), wood (WES) and whole-plant (WPES) economics spectra. Leaf and wood traits are highly intra- and intercorrelated, thus defining not only the LES and WES, but also a WPES. Multi-trait variations in PCAs revealed that the traits which were representative of the acquisitive strategy, i.e., cheap tissue investment and rapid returns on that investment, were clustered at one end, while traits that represented the conservative strategy, i.e., expensive tissue investment and slower returns, were clustered at other end in each of the axes of the leaf and wood syndromes (PC1-axis) and the plant height strategy (PC2-axis). The local WPES, LES and WES were tightly correlated with each other. Evergreens shaped the conservative side, while deciduous species structured the acquisitive side of the WPES and LES. With respect to plant height strategies, trees formulated the acquisitive side and shrub species made up the conservative side of the WPES, LES and WES. In conclusion, our results suggested that the LES and WES were coordinated to a WPES for subtropical species. The finding of this local spectrum of plant form and function would be beneficial for modeling nutrient fluxes and species compositions in the changing climate, but also for understanding species strategies in an evolutionary context. © The Author 2016. Published by Oxford University Press. All rights

  4. STRUCTURAL AND FUNCTIONAL MODEL OF FORMING INFORMATIONAL COMPETENCE OF TECHNICAL UNIVERSITY STUDENTS

    Directory of Open Access Journals (Sweden)

    Taras Ostapchuk

    2016-11-01

    Full Text Available The article elaborates and analyses the structural and functional model of formation of information competence of technical university students. The system and mutual relationships between its elements are revealed. It is found out that the presence of the target structure of the proposed model, process and result-evaluative blocks ensure its functioning and the opportunity to optimize the learning process for technical school students’ information training. It is established that the formation of technical university students’ information competence based on components such as motivational value, as well as operational activity, cognitive, and reflexive one. These criteria (motivation, operational and activity, cognitive, reflective, indexes and levels (reproductive, technologized, constructive forming technical university students’ information competence are disclosed. Expediency of complex organizational and educational conditions in the stages of information competence is justified. The complex organizational and pedagogical conditions include: orientation in the organization and implementation of class work for technical university students’ positive value treatment; the issue of forming professionalism; informatization of educational and socio-cultural environment of higher technical educational institutions; orientation of technical university students’ training to the demands of European and international standards on information competence as a factor in the formation of competitiveness at the labor market; introducing a special course curriculum that will provide competence formation due to the use of information technology in professional activities. Forms (lecture, visualization, problem lecture, combined lecture, scientific online conference, recitals, excursions, etc., tools (computer lab, multimedia projector, interactive whiteboard, multimedia technology (audio, video, the Internet technologies; social networks, etc

  5. Pathologizing poverty: new forms of diagnosis, disability, and structural stigma under welfare reform.

    Science.gov (United States)

    Hansen, Helena; Bourgois, Philippe; Drucker, Ernest

    2014-02-01

    In 1996 the U.S. severely restricted public support for low income people, ending "welfare as we know it." This led to dramatic increases in medicalized forms of support for indigent people, who increasingly rely on disability benefits justified by psychiatric diagnoses of chronic mental illness. We present case studies drawn from ethnographic data involving daily participant-observation between 2005 and 2012 in public clinics and impoverished neighborhoods in New York City, to describe the subjective experience of structural stigma imposed by the increasing medicalization of public support for the poor through a diagnosis of permanent mental disability. In some cases, disability benefits enable recipients to fulfill important social roles (sustaining a vulnerable household and promoting stable parenting). The status of family members who receive a monthly disability check improves within their kin and neighborhood-based networks, counterbalancing the felt stigma of being identified by doctors as "crazy". When a diagnosis of mental pathology becomes a valuable survival strategy constituting the basis for fulfillment of household responsibilities, stigmatizing processes are structurally altered. Through the decades, the stigmatized labels applied to the poor have shifted: from being a symptom of racial weakness, to the culture of poverty, and now to permanent medical pathology. The neoliberal bureaucratic requirement that the poor must repeatedly prove their "disabled" status through therapy and psychotropic medication appears to be generating a national and policy-maker discourse condemning SSI malingerers, resurrecting the 16th century specter of the "unworthy poor". Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. Core-Shell Double Gyroid Structure Formed by Linear ABC Terpolymer Thin Films.

    Science.gov (United States)

    Antoine, Ségolène; Aissou, Karim; Mumtaz, Muhammad; Telitel, Siham; Pécastaings, Gilles; Wirotius, Anne-Laure; Brochon, Cyril; Cloutet, Eric; Fleury, Guillaume; Hadziioannou, Georges

    2018-05-01

    The synthesis and self-assembly in thin-film configuration of linear ABC triblock terpolymer chains consisting of polystyrene (PS), poly(2-vinylpyridine) (P2VP), and polyisoprene (PI) are described. For that purpose, a hydroxyl-terminated PS-b-P2VP (45 kg mol -1 ) building block and a carboxyl-terminated PI (9 kg mol -1 ) are first separately prepared by anionic polymerization, and then are coupled via a Steglich esterification reaction. This quantitative and metal-free catalyst synthesis route reveals to be very interesting since functionalization and purification steps are straightforward, and well-defined terpolymers are produced. A solvent vapor annealing (SVA) process is used to promote the self-assembly of frustrated PS-b-P2VP-b-PI chains into a thin-film core-shell double gyroid (Q 230 , space group: Ia3¯d) structure. As terraces are formed within PS-b-P2VP-b-PI thin films during the SVA process under a CHCl 3 vapor, different plane orientations of the Q 230 structure ((211), (110), (111), and (100)) are observed at the polymer-air interface depending on the film thickness. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Complexing in the systems of thorium tetrabromide-alkali metal bromide and structure of formed compounds

    International Nuclear Information System (INIS)

    Gershanovich, A.Ya.; Suglobova, I.G.

    1981-01-01

    Phase diagrams of the ThBr 4 -MBr binary systems (M=Na, K, Rb, Cs) are obtained using the methods of thermographic and X-ray phase analyses. Congruently melting compounds of the M 2 ThBr 6 form (M=K, Rb, Cs) with melting temperatures of 635, 650 and 680 deg C, respectively, and the NaThBr 5 decomposing in the solid phase reaction at 356 deg C, realized in the systems. The presence of eutectic points is established, their composition and melting temperatures are determined. Roentgenograms of all compounds prepared by the polycrystal method are obtained. K 2 ThBr 6 and Rb 2 ThBr 6 crystallize in the hexagonal crystal system (Rb 2 MnF 6 structure type) with 2 formula units in the lattice cell. The parameters of the K 2 ThBr 6 cell are a=0.752 nm, c=1.180 nm. The cell parameters of the Rb 2 ThBr 6 cell are a=0.758 nm, c=1.224 nm. The Cs 2 ThBr 6 has a pseudocubic tetragonal structure with 4 formula units in a cell. Parameters of the Cs 2 ThBr 6 cell are a=1.137 nm; c=1.069 nm [ru

  8. Assembly of alginate microfibers to form a helical structure using micromanipulation with a magnetic field

    International Nuclear Information System (INIS)

    Sun, Tao; Huang, Qiang; Shi, Qing; Wang, Huaping; Li, Pengyun; Fukuda, Toshio; Hu, Chengzhi; Nakajima, Masahiro

    2016-01-01

    Helical structures assembled using alginate microfibers have a promising spatial architecture mimicking in vivo vessels for culturing vascular cells. However, the helical structure can only be assembled at the macroscale, since a microassembly-based approach has not yet been developed. In this paper, we propose a magnetic-field-based micromanipulation method to fabricate a helical microstructure. By microfluidic spinning, alginate microfibers encapsulating magnetic nanoparticles are synthesized to enable the control of an electromagnetic needle (EMN). We developed a microrobotic system to actuate a micropipette to fix a free end of the microfiber, and then move the EMN to reel the microfiber around a micropillar. The motion of the EMN is guided using an upright microscope and a side-view camera. Because of the limitation of operation space, a spacer sleeve was designed to keep the tip of the EMN attracted to the microfiber, and simultaneously to keep the other part of the EMN isolated from the microfiber. To ensure the availability of the microfiber for continuously coiling, we enable the EMN tip to slide on the surface of the microfiber without changing the tensioning of the microfiber for positioning control. Furthermore, stable and repeatable micromanipulation was achieved to form multi-turn microfiber coils based on the motion planning of the EMN. Finally, we successfully fabricated a helical microstructure that can be applied in vascular tissue engineering in the future. (paper)

  9. High density liquid structure enhancement in glass forming aqueous solution of LiCl

    Science.gov (United States)

    Camisasca, G.; De Marzio, M.; Rovere, M.; Gallo, P.

    2018-06-01

    We investigate using molecular dynamics simulations the dynamical and structural properties of LiCl:6H2O aqueous solution upon supercooling. This ionic solution is a glass forming liquid of relevant interest in connection with the study of the anomalies of supercooled water. The LiCl:6H2O solution is easily supercooled and the liquid state can be maintained over a large decreasing temperature range. We performed simulations from ambient to 200 K in order to investigate how the presence of the salt modifies the behavior of supercooled water. The study of the relaxation time of the self-density correlation function shows that the system follows the prediction of the mode coupling theory and behaves like a fragile liquid in all the range explored. The analysis of the changes in the water structure induced by the salt shows that while the salt preserves the water hydrogen bonds in the system, it strongly affects the tetrahedral hydrogen bond network. Following the interpretation of the anomalies of water in terms of a two-state model, the modifications of the oxygen radial distribution function and the angular distribution function of the hydrogen bonds in water indicate that LiCl has the role of enhancing the high density liquid component of water with respect to the low density component. This is in agreement with recent experiments on aqueous ionic solutions.

  10. STRUCTURES OF LOCAL GALAXIES COMPARED TO HIGH-REDSHIFT STAR-FORMING GALAXIES

    International Nuclear Information System (INIS)

    Petty, Sara M.; De Mello, DuIlia F.; Gallagher, John S.; Gardner, Jonathan P.; Lotz, Jennifer M.; Matt Mountain, C.; Smith, Linda J.

    2009-01-01

    The rest-frame far-ultraviolet morphologies of eight nearby interacting and starburst galaxies (Arp 269, M 82, Mrk 8, NGC 520, NGC 1068, NGC 3079, NGC 3310, and NGC 7673) are compared with 54 galaxies at z ∼ 1.5 and 46 galaxies at z ∼ 4 observed in the Great Observatories Origins Deep Survey (GOODS) taken with the Advanced Camera for Surveys onboard the Hubble Space Telescope. The nearby sample is artificially redshifted to z ∼ 1.5 and 4 by applying luminosity and size scaling. We compare the simulated galaxy morphologies to real z ∼ 1.5 and 4 UV-bright galaxy morphologies. We calculate the Gini coefficient (G), the second-order moment of the brightest 20% of the galaxy's flux (M 20 ), and the Sersic index (n). We explore the use of nonparametric methods with two-dimensional profile fitting and find the combination of M 20 with n an efficient method to classify galaxies as having merger, exponential disk, or bulge-like morphologies. When classified according to G and M 20 20/30% of real/simulated galaxies at z ∼ 1.5 and 37/12% at z ∼ 4 have bulge-like morphologies. The rest have merger-like or intermediate distributions. Alternatively, when classified according to the Sersic index, 70% of the z ∼ 1.5 and z ∼ 4 real galaxies are exponential disks or bulge-like with n>0.8, and ∼ 30% of the real galaxies are classified as mergers. The artificially redshifted galaxies have n values with ∼ 35% bulge or exponential at z ∼ 1.5 and 4. Therefore, ∼ 20%-30% of Lyman-break galaxies have structures similar to local starburst mergers, and may be driven by similar processes. We assume merger-like or clumpy star-forming galaxies in the GOODS field have morphological structure with values n 20 > - 1.7. We conclude that Mrk 8, NGC 3079, and NGC 7673 have structures similar to those of merger-like and clumpy star-forming galaxies observed at z ∼ 1.5 and 4.

  11. Structures of butyl ions formed by electron impact ionization of isomeric butyl halides and alkanes

    International Nuclear Information System (INIS)

    Shold, D.M.; Ausloos, P.

    1978-01-01

    Using a pulsed ion cyclotron resonance (ICR) spectrometer, it is demonstrated that at pressures of about 10 -6 Torr and at observation times ranging from 10 -3 to 0.5 s, isobutane, neopentane, 2,2-dimethylbutane, isobutyl halides, and tert-butyl halides form C 4 H 9 + ions having the tertiary structure. In n-alkanes, 2-methylbutane, 3-methylpentane, n-butyl halides, and sec-butyl halides, both sec-C 4 H 9 + and t-C 4 H 9 + ions are observed, the sec-C 4 H 9 + ions surviving without rearrangement for at least 0.1 s. However, in the case of the halides, a collision-induced isomerization of the sec-C 4 H 9 + to the t-C 4 H 9 + ions occurs. The efficiency of this process increases with the basicity of the alkyl halide. Radiolysis experiments carried out at atmospheric pressures indicate, in agreement with ICR and solution experiments, that at times as short as 10 -10 s the majority of the i-C 4 H 9 + ions from isobutyl bromide rearrange to the t-C 4 H 9 + structure. On the other hand, in the radiolysis of both n-hexane and 3-methylpentane, the abundance of t-C 4 H 9 + relative to sec-C 4 H 9 + is substantially smaller than that observed in the ICR experiments, and decreases with decreasing collision interval. It is suggested that about 90% of the i-C 4 H 9 + can rearrange to t-C 4 H 9 + by simple 1,2-hydride shift without involving secondary or protonated methylcyclopropane structures as intermediates. 4 figures, 2 tables

  12. Investigation of the structure of debris beds formed from fuel rods fragmentation

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Duc-Hanh; Fichot, Florian; Topin, Vincent, E-mail: vincent.topin@irsn.fr

    2017-03-15

    This paper is a study of debris beds that can form in the core of a nuclear power plant under severe accident conditions. Such beds are formed of fragments of pellets and cladding remnants, as observed in the TMI-2 core. Many important issues are related with the morphology of those debris beds: are they coolable in case of water injection and how does molten corium progress through them if they are not coolable? The answers to those questions depend on the structure of the debris bed: porosity, number and arrangement of particles. In order to obtain relevant information, a numerical simulation of the formation of the debris bed is proposed. It relies on a granular approach of the type called “Contact Dynamics” to simulate the collapse of debris and their accumulation. Two different schemes of fuel pellet fragmentation are considered and simulations for different degrees of fragmentation of the pellets are performed. The results show that the number of axial cracks on fuel pellets strongly influences the final porosity of the debris bed. Porosities vary between 31% (less coolable cases) and 45% (similar to TMI-2 observations), with a most probable configuration around 41%. The specific surface of the bed is also evaluated. In the last part, a simple model is used to estimate the impact of the variation in geometry of the numeric debris beds on their flow properties. We show that the permeability and passability can vary respectively with a range of 30% and 15% depending on the number of fragment per pellet. The other benefits of the approach are finally discussed. Among them, the possibility to print 3D samples from the calculated images of debris beds appears as a promising perspective to perform experiments with realistic debris beds.

  13. Process and structures for fabrication of solar cells with laser ablation steps to form contact holes

    Science.gov (United States)

    Harley, Gabriel; Smith, David D; Dennis, Tim; Waldhauer, Ann; Kim, Taeseok; Cousins, Peter John

    2013-11-19

    Contact holes of solar cells are formed by laser ablation to accomodate various solar cell designs. Use of a laser to form the contact holes is facilitated by replacing films formed on the diffusion regions with a film that has substantially uniform thickness. Contact holes may be formed to deep diffusion regions to increase the laser ablation process margins. The laser configuration may be tailored to form contact holes through dielectric films of varying thickness.

  14. Trigonometric parallaxes of high mass star forming regions: the structure and kinematics of the Milky Way

    Energy Technology Data Exchange (ETDEWEB)

    Reid, M. J.; Dame, T. M. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Menten, K. M.; Brunthaler, A.; Wu, Y.; Zhang, B.; Sanna, A.; Sato, M.; Choi, Y. K.; Immer, K. [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Zheng, X. W. [Department of Astronomy, Nanjing University Nanjing 210093 (China); Xu, Y. [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China); Hachisuka, K. [Shanghai Astronomical Observatory, 80 Nandan Rd., Shanghai (China); Moscadelli, L. [Arcetri Observatory, Firenze (Italy); Rygl, K. L. J. [European Space Agency (ESA-ESTEC), Keplerlaan 1, P.O. Box 299, 2200 AG, Noordwijk (Netherlands); Bartkiewicz, A. [Centre for Astronomy, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Grudziadzka 5, 87-100 Torun (Poland)

    2014-03-10

    Over 100 trigonometric parallaxes and proper motions for masers associated with young, high-mass stars have been measured with the Bar and Spiral Structure Legacy Survey, a Very Long Baseline Array key science project, the European VLBI Network, and the Japanese VLBI Exploration of Radio Astrometry project. These measurements provide strong evidence for the existence of spiral arms in the Milky Way, accurately locating many arm segments and yielding spiral pitch angles ranging from about 7° to 20°. The widths of spiral arms increase with distance from the Galactic center. Fitting axially symmetric models of the Milky Way with the three-dimensional position and velocity information and conservative priors for the solar and average source peculiar motions, we estimate the distance to the Galactic center, R {sub 0}, to be 8.34 ± 0.16 kpc, a circular rotation speed at the Sun, Θ{sub 0}, to be 240 ± 8 km s{sup –1}, and a rotation curve that is nearly flat (i.e., a slope of –0.2 ± 0.4 km s{sup –1} kpc{sup –1}) between Galactocentric radii of ≈5 and 16 kpc. Assuming a 'universal' spiral galaxy form for the rotation curve, we estimate the thin disk scale length to be 2.44 ± 0.16 kpc. With this large data set, the parameters R {sub 0} and Θ{sub 0} are no longer highly correlated and are relatively insensitive to different forms of the rotation curve. If one adopts a theoretically motivated prior that high-mass star forming regions are in nearly circular Galactic orbits, we estimate a global solar motion component in the direction of Galactic rotation, V {sub ☉} = 14.6 ± 5.0 km s{sup –1}. While Θ{sub 0} and V {sub ☉} are significantly correlated, the sum of these parameters is well constrained, Θ{sub 0} + V {sub ☉} = 255.2 ± 5.1 km s{sup –1}, as is the angular speed of the Sun in its orbit about the Galactic center, (Θ{sub 0} + V {sub ☉})/R {sub 0} = 30.57 ± 0.43 km s{sup –1} kpc{sup –1}. These parameters improve the accuracy

  15. Cavitation structures formed during the collision of a sphere with an ultra-viscous wetted surface

    KAUST Repository

    Mansoor, Mohammad M.

    2016-05-05

    We investigate the inception of cavitation and resulting structures when a sphere collides with a solid surface covered with a layer of non-Newtonian liquid having a kinematic viscosity of up to (Formula presented.) cSt. We show the existence of shear-stress-induced cavitation during sphere approach towards the base wall (i.e. the pressurization stage) in ultra-viscous films using a synchronized dual-view high-speed imaging system. For the experimental parameters employed, liquids having viscoelastic properties of (Formula presented.) are shown to enable sphere rebound without any prior contact with the solid wall. Cavitation by depressurization (i.e. during rebound) in such non-contact cases is observed to onset after a noticeable delay from when the minimum gap distance is reached. Also, the cavities created originate from remnant bubbles, being the remains of the primary bubble entrapment formed by the lubrication pressure of the air during film entry. Cases where physical contact occurs (contact cases) in 10 000 cSt (Formula presented.) cSt films produce cavities attached to the base wall, which extend into an hourglass shape. In contrast, strikingly different structures occur in the most viscous liquids due to the disproportionality in radial expansion and longitudinal extension along the cavity length. Horizontal shear rates calculated using particle image velocimetry (PIV) measurements show the apparent fluid viscosity to vary substantially as the sphere approaches and rebounds away from the base wall. A theoretical model based on the lubrication assumption is solved for the squeeze flow in the regime identified for shear-induced cavity events, to investigate the criterion for cavity inception in further detail. © 2016 Cambridge University Press

  16. Cavitation structures formed during the collision of a sphere with an ultra-viscous wetted surface

    KAUST Repository

    Mansoor, Mohammad M.; Marston, J. O.; Uddin, J.; Christopher, G.; Zhang, Z.; Thoroddsen, Sigurdur T

    2016-01-01

    We investigate the inception of cavitation and resulting structures when a sphere collides with a solid surface covered with a layer of non-Newtonian liquid having a kinematic viscosity of up to (Formula presented.) cSt. We show the existence of shear-stress-induced cavitation during sphere approach towards the base wall (i.e. the pressurization stage) in ultra-viscous films using a synchronized dual-view high-speed imaging system. For the experimental parameters employed, liquids having viscoelastic properties of (Formula presented.) are shown to enable sphere rebound without any prior contact with the solid wall. Cavitation by depressurization (i.e. during rebound) in such non-contact cases is observed to onset after a noticeable delay from when the minimum gap distance is reached. Also, the cavities created originate from remnant bubbles, being the remains of the primary bubble entrapment formed by the lubrication pressure of the air during film entry. Cases where physical contact occurs (contact cases) in 10 000 cSt (Formula presented.) cSt films produce cavities attached to the base wall, which extend into an hourglass shape. In contrast, strikingly different structures occur in the most viscous liquids due to the disproportionality in radial expansion and longitudinal extension along the cavity length. Horizontal shear rates calculated using particle image velocimetry (PIV) measurements show the apparent fluid viscosity to vary substantially as the sphere approaches and rebounds away from the base wall. A theoretical model based on the lubrication assumption is solved for the squeeze flow in the regime identified for shear-induced cavity events, to investigate the criterion for cavity inception in further detail. © 2016 Cambridge University Press

  17. Detection of G-Quadruplex Structures Formed by G-Rich Sequences from Rice Genome and Transcriptome Using Combined Probes.

    Science.gov (United States)

    Chang, Tianjun; Li, Weiguo; Ding, Zhan; Cheng, Shaofei; Liang, Kun; Liu, Xiangjun; Bing, Tao; Shangguan, Dihua

    2017-08-01

    Putative G-quadruplex (G4) forming sequences (PQS) are highly prevalent in the genome and transcriptome of various organisms and are considered as potential regulation elements in many biological processes by forming G4 structures. The formation of G4 structures highly depends on the sequences and the environment. In most cases, it is difficult to predict G4 formation by PQS, especially PQS containing G2 tracts. Therefore, the experimental identification of G4 formation is essential in the study of G4-related biological functions. Herein, we report a rapid and simple method for the detection of G4 structures by using a pair of complementary reporters, hemin and BMSP. This method was applied to detect G4 structures formed by PQS (DNA and RNA) searched in the genome and transcriptome of Oryza sativa. Unlike most of the reported G4 probes that only recognize part of G4 structures, the proposed method based on combined probes positively responded to almost all G4 conformations, including parallel, antiparallel, and mixed/hybrid G4, but did not respond to non-G4 sequences. This method shows potential for high-throughput identification of G4 structures in genome and transcriptome. Furthermore, BMSP was observed to drive some PQS to form more stable G4 structures or induce the G4 formation of some PQS that cannot form G4 in normal physiological conditions, which may provide a powerful molecular tool for gene regulation.

  18. Structural and functional characteristics of myocard in patients with different forms of atrial fibrillation

    Directory of Open Access Journals (Sweden)

    L. I. Vasilyeva

    2015-02-01

    Full Text Available Aim. To study structural and functional characteristics of myocard in patients with different forms of atrial fibrillation. Atrial fibrillation is the most prevalent arrhythmia in clinical practice. Atrial fibrillation is a progressive disease: the duration of paroxysms increases over time and paroxysmal atrial fibrillation transforms to persistent, the last one becomes refractory to pharmacological and electrical cardioversion in time and transforms to permanent. So assessment of myocardial remodeling in patients with persistent and permanent atrial fibrillation is very actual. Methods and results. According to the aim of the study 133 patients with persistent atrial fibrillation and 100 patients with permanent atrial fibrillation were included into the study. Echocardiographic parameters of left and right atria function were studied. Conclusion. It was found that patients with persistent and permanent atrial fibrillation are characterized with both left and right atrias remodeling. Remodeling of the atrias is less pronounced in patients with permanent atrial fibrillation in comparison with persistent atrial fibrillation patients and arrhythmia recurrence.

  19. Design and strength evaluation of structural joint made by electro-magnetic forming (EMF)

    International Nuclear Information System (INIS)

    Park, Young-Bae; Oh, Soo-Ik; Kim, Heon-Young

    2004-01-01

    Recently, weight reduction of vehicles has been of great interest, and consequently, the use of low-density materials in the automotive industry is increasing every year. Materials should not be substituted such a way that material of component parts is simply changed because there is a problem in achieving stiffness and strength. To achieve these requirements, the automobile should be redesigned totally. Aluminum spaceframe is rapidly being adopted as a body structure for accommodating lightness, stiffness and strength requirement. In aluminum spaceframe manufacturing, it is often required to join aluminum tube. But there are few suitable methods for joining aluminum tube, so that much interest has been focused on testing suitable joining methods. Joining by electromagnetic forming(EMF) can be useful method in joining aluminum tube, which offers some advantages compared with the conventional joining method. In this paper, joining by EMF was investigated as a pre-study for applying an automotive spaceframe. Finite element simulations and strength tests were performed to analyze the influence of geometric parameters on joint strength. Based on these results, configurations of axial joint and torque joint were suggested and guidelines for designing EMF joint were established

  20. Structure and fertilizer properties of byproducts formed in the synthesis of EDDHA.

    Science.gov (United States)

    Hernández-Apaolaza, Lourdes; García-Marco, Sonia; Nadal, Paloma; Lucena, Juan J; Sierra, Miguel A; Gómez-Gallego, Mar; Ramírez-López, Pedro; Escudero, Rosa

    2006-06-14

    The synthesis of commercial EDDHA produces o,o-EDDHA as the main reaction product, together with a mixture of regioisomers (o,p-EDDHA and p,p-EDDHA) and other unknown byproducts also able to complex Fe3+. These compounds have been obtained by direct synthesis, and their structures have been determined by ESI-MS analysis as oligomeric EDDHA-like products, formed by polysubstitution in the phenolic rings. Short-term experiments show that the iron complexes of samples enriched in these oligomeric byproducts have adequate stability in solution, but a significant amount of them is lost after interaction with soils and soil materials. Mildly chlorotic cucumber plants are able to reduce iron better from o,p-EDDHA/Fe3+ than from the iron complexes of the oligomeric byproducts. In hydroponics, the chlorotic soybean susceptible plants have a lower potential for Fe absorption from these byproducts than from o,o-EDDHA/Fe3+ and from o,p-EDDHA/Fe3+. In the studied conditions, the iron chelates of EDDHA byproducts do not have the long-lasting effect shown by o,o-EDDHA/Fe3+ and present a less efficient fast-action effect than the o,p-EDDHA/Fe3+.

  1. Laser micromachining of screen-printed graphene for forming electrode structures

    International Nuclear Information System (INIS)

    Chang, Tien-Li; Chen, Zhao-Chi; Tseng, Shih-Feng

    2016-01-01

    Highlights: • Homogeneous graphene films were prepared by the screen-printing process. • Optimal single-line ablation was performed by ultraviolet nanosecond laser pulses. • Influence of ablation parameters on graphene/glass substrate was clarified. • Electrical measurements of ablated graphene-based device can be investigated. - Abstract: There has been increasing research interest in electronic applications of graphene-based devices fabricated using electrode patterning techniques. This study presents a laser ablation technique along with a screen printing process for fabricating graphene patterns on a glass substrate. First, homogeneous multilayer films on the glass substrate are coated with graphene ink by using the screen printing process. Subsequently, optimal ablation was performed using an ultraviolet nanosecond laser, and the effective number of pulses decreased with an increase in the scanning speed and a decrease in the overlapping rate. Here, the pulsed overlap of a laser spot was determined to be approximately 90% for 75 pulses at a scanning speed of 250 mm/s. Experimental results showed continuous single-line ablation along the laser scanning path in the graphene films. Furthermore, linear current–voltage (I–V) curves showed the multilayer graphene characteristics of ablated devices for forming electrode structures.

  2. The Structure and Form of Folksonomy Tags: The Road to the Public Library Catalog

    Directory of Open Access Journals (Sweden)

    Louise F. Spiteri

    2007-09-01

    Full Text Available This article examines the linguistic structure of folksonomy tags collected over a thirty-day period from the daily tag logs of Del.icio.us, Furl, and Technorati. The tags were evaluated against the National Information Standards Organization (NISO guidelines for the construction of controlled vocabularies. The results indicate that the tags correspond closely to the NISO guidelines pertaining to types of concepts expressed, the predominance of single terms and nouns, and the use of recognized spelling. Problem areas pertain to the inconsistent use of count nouns and the incidence of ambiguous tags in the form of homographs, abbreviations, and acronyms. With the addition of guidelines to the construction of unambiguous tags and links to useful external reference sources, folksonomies could serve as a powerful, flexible tool for increasing the user-friendliness and interactivity of public library catalogs, and also may be useful for encouraging other activities, such as informal online communities of readers and user-driven readers’ advisory services.

  3. Ag nanoparticles formed by femtosecond pulse laser ablation in water: self-assembled fractal structures

    Energy Technology Data Exchange (ETDEWEB)

    Santillán, Jesica M. J. [CONICET La Plata-CIC, Centro de Investigaciones Ópticas (CIOp) (Argentina); Fernández van Raap, Marcela B., E-mail: raap@fisica.unlp.edu.ar; Mendoza Zélis, Pedro; Coral, Diego [CONICET, Instituto de Física La Plata (IFLP) (Argentina); Muraca, Diego [Universidade Estadual de Campinas, Instituto de Física “Gleb Wataghin” (IFGW) (Brazil); Schinca, Daniel C.; Scaffardi, Lucía B., E-mail: lucias@ciop.unlp.edu.ar [CONICET La Plata-CIC, Centro de Investigaciones Ópticas (CIOp) (Argentina)

    2015-02-15

    We report for the first time on the formation of self-assembled fractals of spherical Ag nanoparticles (Nps) fabricated by femtosecond pulse laser ablation of a solid silver target in water. Fractal structures grew both in two and three Euclidean dimensions (d). Ramified-fractal assemblies of 2 nm height and 5–14 μm large, decorated with Ag Nps of 3 nm size, were obtained in a 2d geometry when highly diluted drops of colloidal suspension were dried at a fast heating rate over a mica substrate. When less-diluted drops were dried at slow heating rate, isolated single Nps or rosette-like structures were formed. Fractal aggregates about 31 nm size in 3d geometry were observed in the as-prepared colloidal suspension. Electron diffraction and optical extinction spectroscopy (OES) analyses performed on the samples confirmed the presence of Ag and Ag{sub 2}O. The analysis of the optical extinction spectrum, using the electrostatic approximation of Mie theory for small spheres, showed the existence of Ag bare core, Ag–Ag{sub 2}O and air–Ag core–shell Nps, Ag–Ag{sub 2}O being the most frequent type [69 % relative abundance (r.a.)]. Core-size and shell-thickness distribution was derived from OES. In situ scattering measurements of the Ag colloidal suspension, carried out by small-angle X-ray scattering, indicate a mass fractal composed of packaged 〈D{sub SAXS}〉 = (5 ± 1) nm particles and fractal dimension d{sub f} = 2.5. Ex situ atomic force microscopy imaging displayed well-ramified structures, which, analyzed with box-counting method, yield a fractal dimension d{sub f} = 1.67. The growing behavior of these 2d and 3d self-assembled fractals is consistent with the diffusion-limited aggregation model.

  4. Structure of the Unbound Form of HIV-1 Subtype A Protease: Comparison with Unbound Forms of Proteases from other HIV Subtypes

    Energy Technology Data Exchange (ETDEWEB)

    Robbins, Arthur H.; Coman, Roxana M.; Bracho-Sanchez, Edith; Fernandez, Marty A.; Gilliland, C.Taylor; Li, Mi; Agbandje-McKenna, Mavis; Wlodawer, Alexander; Dunn, Ben M.; McKenna, Robert (NCI); (Florida)

    2010-03-12

    The crystal structure of the unbound form of HIV-1 subtype A protease (PR) has been determined to 1.7 {angstrom} resolution and refined as a homodimer in the hexagonal space group P6{sub 1} to an R{sub cryst} of 20.5%. The structure is similar in overall shape and fold to the previously determined subtype B, C and F PRs. The major differences lie in the conformation of the flap region. The flaps in the crystal structures of the unbound subtype B and C PRs, which were crystallized in tetragonal space groups, are either semi-open or wide open. In the present structure of subtype A PR the flaps are found in the closed position, a conformation that would be more anticipated in the structure of HIV protease complexed with an inhibitor. The amino-acid differences between the subtypes and their respective crystal space groups are discussed in terms of the differences in the flap conformations.

  5. Effect of the strange axial form factor on structure functions for neutral current neutrino scattering in the quasielastic region

    International Nuclear Information System (INIS)

    Kim, Kyungsik

    2011-01-01

    We study the effect of the strange axial form factor on various structure functions for the neutral reaction of neutrino-nucleus scattering in the quasielastic region within the framework of a relativistic single particle model. We use 12 C as the target nucleus, and the incident neutrino energy range is between 150 MeV and 1.5 GeV. The structure functions are extracted at a fixed three momentum transfer and energy transfer by using the intrinsic helicity of neutrino. While the effect of the strange axial form factor is very small, the effect on various structure functions is exhibited explicitly.

  6. An Integrated Modelling and Toolpathing Approach for a Frameless Stressed Skin Structure, Fabricated Using Robotic Incremental Sheet Forming

    DEFF Research Database (Denmark)

    Nicholas, Paul; Stasiuk, David; Nørgaard, Esben Clausen

    2016-01-01

    with performance implications at material, element and structural scales. This paper briefly presents ISF as a method of fabrication, and introduces the context of structures where the skin plays an integral role. It describes the development of an integrated approach for the modelling and fabrication of Stressed...... Skins, an incrementally formed sheet metal structure. The paper then focus upon the use of prototypes and empirical testing as means to inform digital models about fabrication and material parameters including: material forming limits and thinning; the parameterisation of macro and meso simulations...

  7. The emergence of shared leadership in newly-formed teams with an initial structure of vertical leadership: A longitudinal analysis

    OpenAIRE

    Fransen, Katrien; Delvaux, Ellen; Mesquita, Batja; Van Puyenbroeck, Stef

    2018-01-01

    The importance of high-quality leadership for team effectiveness is widely recognized, with recent viewpoints arguing shared leadership to be a more powerful predictor than vertical leadership. To identify changes in leadership structures over time, we longitudinally tracked the leadership structure of 27 newly-formed teams (N = 195), all having an initial structure of vertical leadership. Our findings demonstrated that the average team leadership strengthened over the course of the 24-week p...

  8. Phenotypic and Causal Structure of Conduct Disorder in the Broader Context of Prevalent Forms of Psychopathology

    Science.gov (United States)

    Lahey, Benjamin B.; Waldman, Irwin D.

    2011-01-01

    Background A better understanding of the nature and etiology of conduct disorder (CD) can inform nosology and vice-versa. We posit that any prevalent form of psychopathology, including CD, can be best understood if it is studied in the context of other correlated forms of child and adolescent psychopathology using formal models to guide inquiry. Methods Review of both cross-sectional and longitudinal studies of the place of CD in the phenotypic and causal structure of prevalent psychopathology, with an emphasis on similarities and differences between CD and oppositional defiant disorder (ODD). Papers were located using Web of Science by topic searches with no restriction on year of publication. Results Although some important nosologic questions remain unanswered, the dimensional phenotype of CD is well defined. CD differs from other disorders in its correlates, associated impairment, and course. Nonetheless, it is robustly correlated with many other prevalent dimensions of psychopathology both concurrently and predictively, including both other “externalizing” disorders and some “internalizing” disorders. Based on emerging evidence, we hypothesize that these concurrent and predictive correlations result primarily from widespread genetic pleiotropy, with some genetic factors nonspecifically influencing risk for multiple correlated dimensions of psychopathology. In contrast, environmental influences mostly act to differentiate dimensions of psychopathology from one another both concurrently and over time. CD and ODD share half of their genetic influences, but their genetic etiologies are distinct in other ways. Unlike most other dimensions of psychopathology, half of the genetic influences on CD appear to be unique to CD. In contrast, ODD broadly shares nearly all of its genetic influences with other disorders and has little unique genetic variance. Conclusions CD is a relatively distinct syndrome at both phenotypic and etiologic levels, but much is revealed

  9. Structural Basis of a Thiol-Disulfide Oxidoreductase in the Hedgehog-Forming Actinobacterium Corynebacterium matruchotii.

    Science.gov (United States)

    Luong, Truc Thanh; Tirgar, Reyhaneh; Reardon-Robinson, Melissa E; Joachimiak, Andrzej; Osipiuk, Jerzy; Ton-That, Hung

    2018-05-01

    The actinobacterium Corynebacterium matruchotii has been implicated in nucleation of oral microbial consortia leading to biofilm formation. Due to the lack of genetic tools, little is known about basic cellular processes, including protein secretion and folding, in this organism. We report here a survey of the C. matruchotii genome, which encodes a large number of exported proteins containing paired cysteine residues, and identified an oxidoreductase that is highly homologous to the Corynebacterium diphtheriae thiol-disulfide oxidoreductase MdbA (MdbA Cd ). Crystallization studies uncovered that the 1.2-Å resolution structure of C. matruchotii MdbA (MdbA Cm ) possesses two conserved features found in actinobacterial MdbA enzymes, a thioredoxin-like fold and an extended α-helical domain. By reconstituting the disulfide bond-forming machine in vitro , we demonstrated that MdbA Cm catalyzes disulfide bond formation within the actinobacterial pilin FimA. A new gene deletion method supported that mdbA is essential in C. matruchotii Remarkably, heterologous expression of MdbA Cm in the C. diphtheriae Δ mdbA mutant rescued its known defects in cell growth and morphology, toxin production, and pilus assembly, and this thiol-disulfide oxidoreductase activity required the catalytic motif CXXC. Altogether, the results suggest that MdbA Cm is a major thiol-disulfide oxidoreductase, which likely mediates posttranslocational protein folding in C. matruchotii by a mechanism that is conserved in Actinobacteria IMPORTANCE The actinobacterium Corynebacterium matruchotii has been implicated in the development of oral biofilms or dental plaque; however, little is known about the basic cellular processes in this organism. We report here a high-resolution structure of a C. matruchotii oxidoreductase that is highly homologous to the Corynebacterium diphtheriae thiol-disulfide oxidoreductase MdbA. By biochemical analysis, we demonstrated that C. matruchotii MdbA catalyzes disulfide

  10. Structures, Compositions, and Activities of Live Shewanella Biofilms Formed on Graphite Electrodes in Electrochemical Flow Cells.

    Science.gov (United States)

    Kitayama, Miho; Koga, Ryota; Kasai, Takuya; Kouzuma, Atsushi; Watanabe, Kazuya

    2017-09-01

    An electrochemical flow cell equipped with a graphite working electrode (WE) at the bottom was inoculated with Shewanella oneidensis MR-1 expressing an anaerobic fluorescent protein, and biofilm formation on the WE was observed over time during current generation at WE potentials of +0.4 and 0 V (versus standard hydrogen electrodes), under electrolyte-flow conditions. Electrochemical analyses suggested the presence of unique electron-transfer mechanisms in the +0.4-V biofilm. Microscopic analyses revealed that, in contrast to aerobic biofilms, current-generating biofilm (at +0.4 V) was thin and flat (∼10 μm in thickness), and cells were evenly and densely distributed in the biofilm. In contrast, cells were unevenly distributed in biofilm formed at 0 V. In situ fluorescence staining and biofilm recovery experiments showed that the amounts of extracellular polysaccharides (EPSs) in the +0.4-V biofilm were much smaller than those in the aerobic and 0-V biofilms, suggesting that Shewanella cells suppress the production of EPSs at +0.4 V under flow conditions. We suggest that Shewanella cells perceive electrode potentials and modulate the structure and composition of biofilms to efficiently transfer electrons to electrodes. IMPORTANCE A promising application of microbial fuel cells (MFCs) is to save energy in wastewater treatment. Since current is generated in these MFCs by biofilm microbes under horizontal flows of wastewater, it is important to understand the mechanisms for biofilm formation and current generation under water-flow conditions. Although massive work has been done to analyze the molecular mechanisms for current generation by model exoelectrogenic bacteria, such as Shewanella oneidensis , limited information is available regarding the formation of current-generating biofilms over time under water-flow conditions. The present study developed electrochemical flow cells and used them to examine the electrochemical and structural features of current

  11. A new crystal form of Aspergillus oryzae catechol oxidase and evaluation of copper site structures in coupled binuclear copper enzymes.

    Science.gov (United States)

    Penttinen, Leena; Rutanen, Chiara; Saloheimo, Markku; Kruus, Kristiina; Rouvinen, Juha; Hakulinen, Nina

    2018-01-01

    Coupled binuclear copper (CBC) enzymes have a conserved type 3 copper site that binds molecular oxygen to oxidize various mono- and diphenolic compounds. In this study, we found a new crystal form of catechol oxidase from Aspergillus oryzae (AoCO4) and solved two new structures from two different crystals at 1.8-Å and at 2.5-Å resolutions. These structures showed different copper site forms (met/deoxy and deoxy) and also differed from the copper site observed in the previously solved structure of AoCO4. We also analysed the electron density maps of all of the 56 CBC enzyme structures available in the protein data bank (PDB) and found that many of the published structures have vague copper sites. Some of the copper sites were then re-refined to find a better fit to the observed electron density. General problems in the refinement of metalloproteins and metal centres are discussed.

  12. A new crystal form of Aspergillus oryzae catechol oxidase and evaluation of copper site structures in coupled binuclear copper enzymes.

    Directory of Open Access Journals (Sweden)

    Leena Penttinen

    Full Text Available Coupled binuclear copper (CBC enzymes have a conserved type 3 copper site that binds molecular oxygen to oxidize various mono- and diphenolic compounds. In this study, we found a new crystal form of catechol oxidase from Aspergillus oryzae (AoCO4 and solved two new structures from two different crystals at 1.8-Å and at 2.5-Å resolutions. These structures showed different copper site forms (met/deoxy and deoxy and also differed from the copper site observed in the previously solved structure of AoCO4. We also analysed the electron density maps of all of the 56 CBC enzyme structures available in the protein data bank (PDB and found that many of the published structures have vague copper sites. Some of the copper sites were then re-refined to find a better fit to the observed electron density. General problems in the refinement of metalloproteins and metal centres are discussed.

  13. Incremental electrohydraulic forming - A new approach for the manufacture of structured multifunctional sheet metal blanks

    Science.gov (United States)

    Djakow, Eugen; Springer, Robert; Homberg, Werner; Piper, Mark; Tran, Julian; Zibart, Alexander; Kenig, Eugeny

    2017-10-01

    Electrohydraulic Forming (EHF) processes permit the production of complex, sharp-edged geometries even when high-strength materials are used. Unfortunately, the forming zone is often limited as compared to other sheet metal forming processes. The use of a special industrial-robot-based tool setup and an incremental process strategy could provide a promising solution for this problem. This paper describes such an innovative approach using an electrohydraulic incremental forming machine, which can be employed to manufacture the large multifunctional and complex part geometries in steel, aluminium, magnesium and reinforced plastic that are employed in lightweight constructions or heating elements.

  14. Structural Origin of the Enhanced Glass-Forming Ability Induced by Microalloying Y in the ZrCuAl Alloy

    Directory of Open Access Journals (Sweden)

    Gu-Qing Guo

    2016-03-01

    Full Text Available In this work, the structural origin of the enhanced glass-forming ability induced by microalloying Y in a ZrCuAl multicomponent system is studied by performing synchrotron radiation experiments combined with simulations. It is revealed that the addition of Y leads to the optimization of local structures, including: (1 more Zr-centered and Y-centered icosahedral-like clusters occur in the microstructure; (2 the atomic packing efficiency inside clusters and the regularity of clusters are both enhanced. These structural optimizations help to stabilize the amorphous structure in the ZrCuAlY system, and lead to a high glass-forming ability (GFA. The present work provides an understanding of GFAs in multicomponent alloys and will shed light on the development of more metallic glasses with high GFAs.

  15. Chemical and Charge Imbalance Induced by Radionuclide Decay: Effects on Waste Form Structure

    Energy Technology Data Exchange (ETDEWEB)

    Van Ginhoven, Renee M.; Jaffe, John E.; Jiang, Weilin; Strachan, Denis M.

    2011-04-01

    This is a milestone document covering the activities to validate theoretical calculations with experimental data for the effect of the decay of 90Sr to 90Zr on materials properties. This was done for a surragate waste form strontium titanate.

  16. Charge form factors and alpha-cluster internal structure of 12C

    International Nuclear Information System (INIS)

    Luk'yanov, V.K.; Zemlyanaya, E.V.; Kadrev, D.N.; Antonov, A.N.; Spasova, K.; Anagnostatos, G.S.; Ginis, P.; Giapitzakis, J.

    1999-01-01

    The transition densities and form factors of 0 + , 2 + , and 3 - states in 12 C are calculated in alpha-cluster model using the triangle frame with clusters in the vertices. The wave functions of nucleons in the alpha clusters are taken as they were obtained in the framework of the models used for the description of the 4 He form factor and momentum distribution which are based on the one-body density matrix construction. They contain effects of the short-range NN correlations, as well as the d-shell admixtures in 4 He. Calculations and the comparison with the experimental data show that visible effects on the form and magnitude of the 12 C form factors take place, especially at relatively large momentum transfers

  17. The Use of Explosive Forming for Fastening and Joining Structural and Pressure Components

    Science.gov (United States)

    Schroeder, J. W.

    1985-01-01

    Explosive expansion of tubes into tubesheets has been used for over 20 years in the fabrication and repair of shell and tube heat exchangers. The use of explosives to perform these expansions has offered several distinct advantages over other methods. First, the process is fast and economical and can be performed with minimal training of personnel. Secondly, explosive forming does not cause the deleterious metallurgical effects which often result from other forming operations. In addition, the process can be performed remotely without the need for sophisticated handling equipment. The expansion of tubes into tubesheets is only one of many possible fastening and joining applications for which explosive forming can be used to achieve highly successful results. The explosive forming process and where it has been used are described. In addition, some possible adaptations to other joining applications are identified and discussed.

  18. Exploring the role of cognitive and structural forms of social capital in ...

    African Journals Online (AJOL)

    The article presents a synthesis of data from three village case studies focusing on how structural and cognitive social capital may have influenced the progression of the HIV epidemic in the Kagera region of Tanzania. Grounded theory was used to develop a theoretical model describing the possible links between structural ...

  19. Synthesis, structure and complex forming ability of phosphorylated derivatives of heterocyclic compounds

    International Nuclear Information System (INIS)

    Babaev, B.N.

    2004-01-01

    Full text: The derivatives of acids of phosphorus, due to variety of properties, are a subject of numerous researches. Now it is known, that the derivatives of acids of phosphorus apart from insect, neurotoxic, antienzym and other kinds of physiological activity have also complex forming properties. As extra gents of noble metals particularly are analyzed by the derivatives of dithio phosphor of acids although organ phosphorus compounds with one nuclear of sulfur make extraction properties. Therefore, with the purpose of detection of effective extra gents of ions of argentum the phosphorylated derivatives of heterogeneous ring compounds were synthesized: Ph(RO)P(O)Cl + HOCH(CH 3 )CH 2 -R ' -> Ph(RO)P(O)OCH(CH 3 )CH 2 -R ' + HCl. R C 2 H 5 - C 6 H 13 , R ' = a piperidine, morpholine, anabasine Structure of the obtained connections is confirmed by the results IR -, Pm- and mass- spectrometry. In an IR-spectrum O-hexyl-O - [piperidynoisopropyl] phenylphosphonate has lines of absorption bands of the following functional groups (ν, cm -1 ): (P-O-C 5 H 11 ) 990-1000, (P = 0) 1260, (P-C 6 H 5 )1450, (C-N in cycle) 1550. In an IR-spectrum O-pentyl-[anabasinoisopropyl] phenylphosphonate has lines of absorption bands of the following functional groups (ν, cm -1 ): (P-O-C 5 H 11 ) 990-1000, (P = 0) 1250, (P-C 6 H 5 )1450, (C-N in cycle) 1550. In a spectrum PMR about O-pentyl-[morpholyniisopropyl] phenylphosphonate in the field of a weak field (7, 18-7, 29 p.m.) the multiplet about tones of phenyl group is watched. Me tin proton resonate at 4,66 m.d.as multiplet The signals O-CH 2 of protons of morpholinic cycle appear at 3,58 m.d.. 4H) by the way of triplet. The protons N-CH 2 (6H) three methylene groups will derivate a composite multiple at 2, 10-2, 70 m.d.. The signal of metil group's protons (3H) is watched at 1,15m.d.as doublet. Final metal group resonates at 0, 87 p.m. Six of C-CH 2 of groups give a complex signal in the field of 1, 2-1, 8 m.d. The obtained connections

  20. Laser rapid forming technology of high-performance dense metal components with complex structure

    Science.gov (United States)

    Huang, Weidong; Chen, Jing; Li, Yanming; Lin, Xin

    2005-01-01

    Laser rapid forming (LRF) is a new and advanced manufacturing technology that has been developed on the basis of combining high power laser cladding technology with rapid prototyping (RP) to realize net shape forming of high performance dense metal components without dies. Recently we have developed a set of LRF equipment. LRF experiments were carried out on the equipment to investigate the influences of processing parameters on forming characterizations systematically with the cladding powder materials as titanium alloys, superalloys, stainless steel, and copper alloys. The microstructure of laser formed components is made up of columnar grains or columnar dendrites which grow epitaxially from the substrate since the solid components were prepared layer by layer additionally. The result of mechanical testing proved that the mechanical properties of laser formed samples are similar to or even over that of forging and much better than that of casting. It is shown in this paper that LRF technology is providing a new solution for some difficult processing problems in the high tech field of aviation, spaceflight and automobile industries.

  1. Mechanical properties of regular hexahedral lattice structure formed by selective laser melting

    International Nuclear Information System (INIS)

    Sun, Jianfeng; Yang, Yongqiang; Wang, Di

    2013-01-01

    The Ti–6Al–4V lattice structure is widely used in the aerospace field. This research first designs a regular hexahedral unit, processes the lattice structure composed of the Ti–6Al–4V units by selective laser melting technology, obtains the experimental fracture load and the compression deformation of them through compression tests, then conducts a simulation of the unit and the lattice structure through ANSYS to analyze the failure point. Later, according to the force condition of the point, the model of maximum load is built, through which the analytical formula of the fracture load of the unit and the lattice structure are obtained. The results of groups of experiments demonstrate that there exists an exponential relationship between the practical fracture load and the porosity of the lattice structure. There also exists a trigonometric function relationship between the compression deformation and the porosity of the lattice structure. The fracture analysis indicates that fracture of the units and lattice structure is brittle fracture due to cleavage fracture. (paper)

  2. Structural evidence for the partially oxidized dipyrromethene and dipyrromethanone forms of the cofactor of porphobilinogen deaminase: structures of the Bacillus megaterium enzyme at near-atomic resolution

    International Nuclear Information System (INIS)

    Azim, N.; Deery, E.; Warren, M. J.; Wolfenden, B. A. A.; Erskine, P.; Cooper, J. B.; Coker, A.; Wood, S. P.; Akhtar, M.

    2014-01-01

    The enzyme porphobilinogen deaminase (PBGD; hydroxymethylbilane synthase; EC 2.5.1.61) catalyses a key early step in the biosynthesis of tetrapyrroles in which four molecules of the monopyrrole porphobilinogen are condensed to form a linear tetrapyrrole. Two near-atomic resolution structures of PBGD from B. megaterium are reported that demonstrate the time-dependent accumulation of partially oxidized forms of the cofactor, including one that possesses a tetrahedral C atom in the terminal pyrrole ring. The enzyme porphobilinogen deaminase (PBGD; hydroxymethylbilane synthase; EC 2.5.1.61) catalyses an early step of the tetrapyrrole-biosynthesis pathway in which four molecules of the monopyrrole porphobilinogen are condensed to form a linear tetrapyrrole. The enzyme possesses a dipyrromethane cofactor, which is covalently linked by a thioether bridge to an invariant cysteine residue (Cys241 in the Bacillus megaterium enzyme). The cofactor is extended during the reaction by the sequential addition of the four substrate molecules, which are released as a linear tetrapyrrole product. Expression in Escherichia coli of a His-tagged form of B. megaterium PBGD has permitted the X-ray analysis of the enzyme from this species at high resolution, showing that the cofactor becomes progressively oxidized to the dipyrromethene and dipyrromethanone forms. In previously solved PBGD structures, the oxidized cofactor is in the dipyromethenone form, in which both pyrrole rings are approximately coplanar. In contrast, the oxidized cofactor in the B. megaterium enzyme appears to be in the dipyrromethanone form, in which the C atom at the bridging α-position of the outer pyrrole ring is very clearly in a tetrahedral configuration. It is suggested that the pink colour of the freshly purified protein is owing to the presence of the dipyrromethene form of the cofactor which, in the structure reported here, adopts the same conformation as the fully reduced dipyrromethane form

  3. Environment as a basis for the design of advertising structures by forming

    Science.gov (United States)

    Khmelevsky, Y. P.; Seryakov, V. A.; Mamontov, G. Y.; Tsarenko, D. T.

    2017-01-01

    A few different neighbouring styles of architectural forms are quite frequent in the cities of great historical past. As a result, a designer or architect has to solve the complex problem while designing the objects within such environment, i.e. one has to fit them naturally into the existing site development. Often, form making is found to be hard, due to the fact that the existing architectural forms of totally different stylistic execution coexist in the visual proximity. Presently, placement of the advertising bills in urban environment is both an urgent and debatable issue. On the one hand, advertising providers are keen to present their product bigger and brighter, on the other hand, the overall and eye-catching exhibition stands can be disharmonious with the surrounding architectural ensemble of the city. This situation is relevant for every cultural city.

  4. Relativistic instant-form approach to the structure of two-body composite systems

    International Nuclear Information System (INIS)

    Krutov, A.F.; Troitsky, V.E.

    2002-01-01

    An approach to the electroweak properties of two-particle composite systems is developed. The approach is based on the use of the instant form of relativistic Hamiltonian dynamics. The main feature of this approach is the method of construction of the matrix element of the electroweak current operator. The electroweak current matrix element satisfies the relativistic covariance conditions and in the case of the electromagnetic current also the conservation law automatically. The properties of the system as well as the approximations are formulated in terms of form factors. The approach makes it possible to formulate relativistic impulse approximation in such a way that the Lorentz covariance of the current is ensured. In the electromagnetic case the current conservation law is also ensured. Our approach gives good results for the pion electromagnetic form factor in the whole range of momentum transfers available for experiments at present time, as well as for the lepton decay constant of pions

  5. Production of Curved Precast Concrete Elements for Shell Structures and Free-form Architecture using the Flexible Mould Method

    NARCIS (Netherlands)

    Schipper, H.R.; Grünewald, S.; Eigenraam, P.; Raghunath, P.; Kok, M.A.D.

    2014-01-01

    Free-form buildings tend to be expensive. By optimizing the production process, economical and well-performing precast concrete structures can be manufactured. In this paper, a method is presented that allows producing highly accurate double curved-elements without the need for milling two expensive

  6. Ability of nitrones of various structures to control the radical polymerization of styrene mediated by in situ formed nitroxides.

    NARCIS (Netherlands)

    Sciannamea, V.; Guerrero-Sanchez, C.A.; Schubert, U.S.; Catala, J.-M.; Jerome, R.; Detrembleur, C.

    2005-01-01

    The ability of several nitrones to control the radical polymerization of styrene at 110 °C has been investigated by high-throughput experimentation. The nitrone/free radical initiator pair dictates the structure of the nitroxide and the alkoxyamine formed in situ, which determines the position of

  7. Relativity, Symmetry, and the Structure of Quantum Theory, Volume 2; Point form relativistic quantum mechanics

    Science.gov (United States)

    Klink, William H.; Schweiger, Wolfgang

    2018-03-01

    This book covers relativistic quantum theory from the point of view of a particle theory, based on the irreducible representations of the Poincaré group, the group that expresses the symmetry of Einstein relativity. There are several ways of formulating such a theory; this book develops what is called relativistic point form quantum mechanics, which, unlike quantum field theory, deals with a fixed number of particles in a relativistically invariant way. A chapter is devoted to applications of point form quantum mechanics to nuclear physics.

  8. Advanced Structures and Compositions for 3D Forming of Cellulosic Fibers

    OpenAIRE

    Khakalo, Alexey

    2017-01-01

    The objective of this thesis was to systematically investigate strategies to endow fiber-based materials with toughness and formability. Bio-based polymers and green treatments were applied to develop 3D packaging structures. Formability, the material's ability for three-dimensional shaping, was achieved by plastic deformations in paper structures that were defect-free in terms of appearance and functionality. A set of methods to improve paper toughness was explored, including: (a) combined m...

  9. The capital structure impact on forming company’s accounting policy

    OpenAIRE

    Česnavičiūtė, Giedrė

    2011-01-01

    KEWORDS: Accounting policy, accounting policy choice, disclosure of accounting policies, capital structure, financial leverage, legitimacy theory, agency theory, signal theory, stakeholder theory. The optimal structure of the capital has a huge impact assuring its goals and financial stability. The company’s appropriate situation of financial condition depends on the accounting policies formation as well. In this paper there was made the investigation of correlation of company’s capital struc...

  10. METHODICAL APPROACHES TO FORMING INNOVATIVE PROJECT AND ENTERPRISE MANAGEMENT ORGANIZATIONAL STRUCTURES

    Directory of Open Access Journals (Sweden)

    A. O. Baklanov

    2011-01-01

    Full Text Available The following principles are discussed as methodical bases of the choice of innovative project and enterprise management organizational structures: hierarchism, bureaucratization, adhocratie, tent organization, lean business engineering, rational organization, amorphous organization, teaching organization. Conditions that complicate industrial and technological processes influence enterprise management process dynamics. The variety of existing types of organizational structures is determined by industrial, economic, psychological and social conditions.

  11. Conditional activation of associative semantic structures:forming and transmitting impressions of personality

    OpenAIRE

    Nunes, Ludmila Duarte da Silva

    2012-01-01

    Tese de doutoramento, Psicologia (Cognição Social), Universidade de Lisboa, Faculdade de Psicologia, 2012 In the presented line of research we intended to systematically study the importance of memory to the formation and transmission of impressions of personality. We consider that impressions of personality are grounded in associative structures (e.g., Asch, 1946), which should be prone to similar memory distortions that other associative memory structures are (e.g., Roediger& McDermott, ...

  12. Structural biologists capture detailed image of gene regulator’s fleeting form | Center for Cancer Research

    Science.gov (United States)

    Using an ultrafast, high-intensity radiation source called an X-ray free-electron laser (XFEL), scientists have captured an atomic-level picture of an RNA structure called a riboswitch as it reorganizes itself to regulate protein production. The structure they visualized has never before been seen, and likely exists for only milliseconds after the riboswitch first encounters its activating molecule.  Read more...  

  13. Characterization of bainitic/martensitic structures formed in isothermal treatments below the M

    NARCIS (Netherlands)

    Navarro Lopez, A.; Hidalgo Garcia, J.; Sietsma, J.; Santofimia Navarro, M.J.

    2017-01-01

    Advanced Multiphase High Strength Steels are generally obtained by applying isothermal treatments around the martensite start temperature (Ms). Previous investigations have shown that bainitic ferrite can form from austenite in isothermal treatments below Ms, where its

  14. On the crystalline structures of iron oxides formed during the removal process of iron in water

    International Nuclear Information System (INIS)

    Cho, Bongyeon; Fujita, Kenji; Oda, Katsuro; Ino, Hiromitsu

    1993-01-01

    The iron oxide samples collected from both filtration and batch reactors were analysed by X-ray diffraction and Moessbauer spectroscopy. In the filtration of water containing iron, the oxidized form of iron was determined to be ferrihydrite. In contrast, in the batch experiment without filtration, iron was oxidized to microcrystalline goethite. (orig.)

  15. Development of millimeter-wave accelerating structures using precision metal forming technology

    Energy Technology Data Exchange (ETDEWEB)

    None

    2003-06-03

    High gradients in radio-frequency (RF) driven accelerators require short wavelengths that have the concomitant requirements of small feature size and high tolerances, 1-2 {micro}m for millimeter wavelengths. Precision metal-forming stampling has the promise of meeting those tolerances with high production rates. This STI will evaluate that promise.

  16. Methods of forming and using porous structures for energy efficient separation of light gases by capillary condensation

    Science.gov (United States)

    Calamur, Narasimhan; Carrera, Martin E.; Devlin, David J.; Archuleta, Tom

    2000-01-01

    The present invention relates to an improved method and apparatus for separating one or more condensable compounds from a mixture of two or more gases of differing volatilities by capillary fractionation in a membrane-type apparatus, and a method of forming porous structures therefor. More particularly, the invention includes methods of forming and using an apparatus consisting, at least in part, of a porous structure having capillary-type passages extending between a plurality of small openings on the first side and larger openings on a second side of the structure, the passages being adapted to permit a condensed liquid to flow therethrough substantially by capillary forces, whereby vapors from the mixture are condensed, at least in part, and substantially in and adjacent to the openings on the first side, and are caused to flow in a condensed liquid state, substantially in the absence of vapor, from the openings on the first side to the openings on the second side.

  17. DO22-(Cu,Ni)3Sn intermetallic compound nanolayer formed in Cu/Sn-nanolayer/Ni structures

    International Nuclear Information System (INIS)

    Liu Lilin; Huang, Haiyou; Fu Ran; Liu Deming; Zhang Tongyi

    2009-01-01

    The present work conducts crystal characterization by High Resolution Transmission Electron Microscopy (HRTEM) on Cu/Sn-nanolayer/Ni sandwich structures associated with the use of Energy Dispersive X-ray (EDX) analysis. The results show that DO 22 -(Cu,Ni) 3 Sn intermetallic compound (IMC) ordered structure is formed in the sandwich structures at the as-electrodeposited state. The formed DO 22 -(Cu,Ni) 3 Sn IMC is a homogeneous layer with a thickness about 10 nm. The DO 22 -(Cu,Ni) 3 Sn IMC nanolayer is stable during annealing at 250 deg. C for 810 min. The formation and stabilization of the metastable DO 22 -(Cu,Ni) 3 Sn IMC nanolayer are attributed to the less strain energy induced by lattice mismatch between the DO 22 IMC and fcc Cu crystals in comparison with that between the equilibrium DO 3 IMC and fcc Cu crystals.

  18. Evolution and mechanism of the periodical structures formed on Ti plate under femtosecond laser irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Dong, E-mail: ld20501@126.com; Chen, Chuansong, E-mail: chencs@sdnu.edu.cn; Man, Baoyuan, E-mail: byman@sdnu.edu.cn; Meng, Xue; Sun, Yanna, E-mail: sunyuannaa@163.com; Li, Feifei

    2016-08-15

    Highlights: • Investigate the evolution and succession of three types of fs-laser induced periodic surface structures (FLIPSSs). • Achieve the laser processing window of each type of the FLIPSS. • Explain the formation and evolvement of the ripple structure in the respective of surface plasma wave (SPW). • Ascribe the interaction between the transmitted laser and the reflected laser at the two surfaces of the biconvex lens to the formation of ring structure. - Abstract: This work investigates the femtosencond laser (fs-laser) induced periodical surface structures (FLIPSS) on titanium plate including the concentric rings, microgrooves and subwavelength ripples. The evolution of the three types of the structures at different laser fluence and shot number is investigated experimentally in detail. The competition mechanisms exist among the different FLIPSS. A processing window for each resulting FLIPSS is obtained. In order to give an overall understanding of the FLIPSS, the formation mechanisms of each type of FLIPSS are discussed. The formation of the ripples is well explained by the propagating of the surface plasma wave (SPW) on the air/Ti interface. The evolutions of the ripple distribution are well understood according to this model as well. It is concluded that the interaction of the scattered wave of the laser light with the surface wave is concluded to give rise to the microgroove structure. According to our observation, the shape of the concentric rings does not change with the variation of the laser fluence and pulse number. The structure could be originated from the optical interference between the transmitted and reflected laser beams by the two surfaces of the biconvex lens. This investigation could not only make a further understanding of the formations of FLIPSS but also provide the possibility to control the surface morphologies in laser processing.

  19. Structure and properties of cerium oxides in bulk and nanoparticulate forms

    International Nuclear Information System (INIS)

    Gangopadhyay, Shruba; Frolov, Dmitry D.; Masunov, Artëm E.; Seal, Sudipta

    2014-01-01

    The experimental and computational studies on the cerium oxide nanoparticles, as well as stoichiometric phases of bulk ceria are reviewed. Based on structural similarities of these phases in hexagonal aspect, electroneutral and non-polar pentalayers are identified as building blocks of type A sesquioxide structure. The idealized core/shell structure of the ceria nanoparticles is described as dioxide core covered by a single pentalayer of sesquioxide, which explains the exceptional stability of subsurface vacancies in nanoceria. The density functional theory (DFT) predictions of the lattice parameters and elastic moduli for the Ce(IV) and Ce(III) oxides at the hybrid DFT level are also presented. The calculated values for both compounds agree with available experimental data and allow predicting changes in the lattice parameter with decreasing size of the nanoparticles. The lattice parameter is calculated as equilibrium between contraction of sesquioxide structure in the core, and expansion of dioxide structure in the shell of the nanoparticle. This is consistent with available XRD data on ceria NPs obtained in mild aqueous conditions. The core/shell model, however, breaks down when applied to the size dependence of lattice parameter in NPs obtained by the laser ablation techniques

  20. The structural and phase state formed in construction titanium alloy by radial forging

    Energy Technology Data Exchange (ETDEWEB)

    Shlyakhova, Galina V.; Danilov, Vladimir I.; Orlova, Dina V.; Zuev, Lev B. [Institute of Strength Physics and Materials Science SB RAS, Tomsk (Russian Federation); Zavodchikov, Aleksandr S. [Perm State Technical University, Perm (Russian Federation)

    2011-07-01

    The feasibility of rod manufacture from construction titanium alloy using radial forging on a high duty machine SXK16 was investigated. The investigations were carried on for titanium rod samples using the methods of metallography, electron transmission microscophy and X-ray analysis. The results obtained are described herein. It is found that radial forging results in the formation of homogeneous fine-grained structure.Using radial forging process, high-quality items are produced. As-worked material has submicrocrystalline globular structure and an optimal α:β phase ratio. Besides, the technology is more cost-effective relative to conventional flow charts. Key words: forging, titanium alloy, fine-grain structure, substructure, pore size.

  1. Process for growing a film epitaxially upon an oxide surface and structures formed with the process

    Science.gov (United States)

    McKee, Rodney A.; Walker, Frederick J.

    1995-01-01

    A process and structure wherein a film comprised of a perovskite or a spinel is built epitaxially upon a surface, such as an alkaline earth oxide surface, involves the epitaxial build up of alternating constituent metal oxide planes of the perovskite or spinel. The first layer of metal oxide built upon the surface includes a metal element which provides a small cation in the crystalline structure of the perovskite or spinel, and the second layer of metal oxide built upon the surface includes a metal element which provides a large cation in the crystalline structure of the perovskite or spinel. The layering sequence involved in the film build up reduces problems which would otherwise result from the interfacial electrostatics at the first atomic layers, and these oxides can be stabilized as commensurate thin films at a unit cell thickness or grown with high crystal quality to thicknesses of 0.5-0.7 .mu.m for optical device applications.

  2. Form Exploration of Folded Plate Timber Structures based on Performance Criteria

    DEFF Research Database (Denmark)

    Falk, Andreas; Buelow, Peter Von

    2011-01-01

    This paper presents an explorative study on applications of cross-laminated timber (CLT) elements in shell structures. Previous studies of plate tensegrity, folded plate roofs interacting with stabilising steel-based systems and studies inspired by origami show a widening range of possibilities...... to develop timber-based shells. Steadily rising interest in rationality during pre-fabrication, transport and on-site construction in contemporary industrialised production increases the competitiveness of CLT-based elements and systems and the architectural applications are getting more common and more...... experimental. Folded plate structures which are the focus of this paper present several issues of structural importance – potential mechanisms, subdivision of surfaces etc. – and the hereby presented study aims at exploring developed typologies, using computer tools for developed optimisation procedures...

  3. Crystal structures of the free and inhibited forms of plasmepsin I (PMI) from Plasmodium falciparum.

    Science.gov (United States)

    Bhaumik, Prasenjit; Horimoto, Yasumi; Xiao, Huogen; Miura, Takuya; Hidaka, Koushi; Kiso, Yoshiaki; Wlodawer, Alexander; Yada, Rickey Y; Gustchina, Alla

    2011-07-01

    Plasmepsin I (PMI) is one of the four vacuolar pepsin-like proteases responsible for hemoglobin degradation by the malarial parasite Plasmodium falciparum, and the only one with no crystal structure reported to date. Due to substantial functional redundancy of these enzymes, lack of inhibition of even a single plasmepsin can defeat efforts in creating effective antiparasitic agents. We have now solved crystal structures of the recombinant PMI as apoenzyme and in complex with the potent peptidic inhibitor, KNI-10006, at the resolution of 2.4 and 3.1Å, respectively. The apoenzyme crystallized in the orthorhombic space group P2(1)2(1)2(1) with two molecules in the asymmetric unit and the structure has been refined to the final R-factor of 20.7%. The KNI-10006 bound enzyme crystallized in the tetragonal space group P4(3) with four molecules in the asymmetric unit and the structure has been refined to the final R-factor of 21.1%. In the PMI-KNI-10006 complex, the inhibitors were bound identically to all four enzyme molecules, with the opposite directionality of the main chain of KNI-10006 relative to the direction of the enzyme substrates. Such a mode of binding of inhibitors containing an allophenylnorstatine-dimethylthioproline insert in the P1-P1' positions, previously reported in a complex with PMIV, demonstrates the importance of satisfying the requirements for the proper positioning of the functional groups in the mechanism-based inhibitors towards the catalytic machinery of aspartic proteases, as opposed to binding driven solely by the specificity of the individual enzymes. A comparison of the structure of the PMI-KNI-10006 complex with the structures of other vacuolar plasmepsins identified the important differences between them and may help in the design of specific inhibitors targeting the individual enzymes. Published by Elsevier Inc.

  4. Generation of forming limit bands for ultra-high-strength steels in car body structures

    Science.gov (United States)

    Bayat, Hamid Reza; Sarkar, Sayantan; Italiano, Francesco; Bach, Aleksandar; Wulfinghoff, Stephan; Reese, Stefanie

    2018-05-01

    The application of ultra-high-strength steels in safety-related automotive components has led to higher safety levels as well as weight reduction. Nevertheless, this class of advanced high-strength steels (AHSS) show material scatter due to its manufacturing processes. To address this problem in advance, it is of significance not only to model the failure of the sheet metal but also to specify a band for the necking regime. The former is described by a forming limit curve (FLC), whereas a forming limit band (FLB) introduces the upper and lower bounds for the permissible strains. The objective of the present work is to generate a robust prediction of the strain-based failure of the sheet metal during a car crash. The FLCs are generated numerically applying a modified Marciniak-Kuczynski (MK) model, where the existence of an angled groove is mandatory. This assures to obtain the maximum admissible strain. In addition, a zero extension angle is utilized for the left hand side of the FLC (tension-compression). The material scatter is captured in experiments and applied in the hardening relations. Necking strains are recorded experimentally by a digital image correlation based system (ARAMIS). Later, they are fit into the FLC based on an inhomogeneity parameter fi from the MK model. In order to generate a theoretical FLB, first a statistical approach is exploited to take the experimental data into consideration. Eventually, the forming limit band distinguishes between safe, necking and failed regions.

  5. An Assessment of Binary Metallic Glasses: Correlations Between Structure, Glass Forming Ability and Stability (Preprint)

    Science.gov (United States)

    2011-07-01

    volume (via indentation, relaxation or positron annihilation ) are expected to significantly clarify structural descriptions. Further insights may be... applicability of the concept of smaller spheres filling the interstices of larger spheres diminishes with decreasing difference in size, the efficient...alloys observed by Mossbauer spectroscopy and calorimetry’, Rapidly Quenched Metals, Proc. 4th International Conference on Rapidly Quenched Metals

  6. Improvement of formability for fabricating thin continuously corrugated structures in sheet metal forming process

    International Nuclear Information System (INIS)

    Choi, Sung Woo; Park, Sang Hu; Park, Seong Hun; Ha, Man Yeong; Jeong, Ho Seung; Cho, Jong Rae

    2012-01-01

    A stamping process is widely used for fabricating various sheet metal parts for vehicles, airplanes, and electronic devices by the merit of low processing cost and high productivity. Recently, the use of thin sheets with a corrugated structure for sheet metal parts has rapidly increased for use in energy management devices, such as heat exchangers, separators in fuel cells, and many others. However, it is not easy to make thin corrugated structures directly using a single step stamping process due to their geometrical complexity and very thin thickness. To solve this problem, a multi step stamping (MSS) process that includes a heat treatment process to improve formability is proposed in this work: the sequential process is the initial stamping, heat treatment, and final shaping. By the proposed method, we achieved successful results in fabricating thin corrugated structures with an average thickness of 75μm and increased formability of about 31% compared to the single step stamping process. Such structures can be used in a plate-type heat exchanger requiring low weight and a compact shape

  7. Weak form of Stokes-Dirac structures and geometric discretization of port-Hamiltonian systems

    Science.gov (United States)

    Kotyczka, Paul; Maschke, Bernhard; Lefèvre, Laurent

    2018-05-01

    We present the mixed Galerkin discretization of distributed parameter port-Hamiltonian systems. On the prototypical example of hyperbolic systems of two conservation laws in arbitrary spatial dimension, we derive the main contributions: (i) A weak formulation of the underlying geometric (Stokes-Dirac) structure with a segmented boundary according to the causality of the boundary ports. (ii) The geometric approximation of the Stokes-Dirac structure by a finite-dimensional Dirac structure is realized using a mixed Galerkin approach and power-preserving linear maps, which define minimal discrete power variables. (iii) With a consistent approximation of the Hamiltonian, we obtain finite-dimensional port-Hamiltonian state space models. By the degrees of freedom in the power-preserving maps, the resulting family of structure-preserving schemes allows for trade-offs between centered approximations and upwinding. We illustrate the method on the example of Whitney finite elements on a 2D simplicial triangulation and compare the eigenvalue approximation in 1D with a related approach.

  8. Structure and properties of fixed joints formed by ultrasonic-assisted friction-stir welding

    Energy Technology Data Exchange (ETDEWEB)

    Fortuna, S. V., E-mail: s-fortuna@ispms.ru; Ivanov, K. V., E-mail: ikv@ispms.ru; Eliseev, A. A., E-mail: alan@ispms.ru [Institute of Strength Physics and Materials ScienceTomsk, 634055 (Russian Federation); Tarasov, S. Yu., E-mail: tsy@ispms.ru; Ivanov, A. N., E-mail: ivan@ispms.ru; Rubtsov, V. E., E-mail: rvy@ispms.ru; Kolubaev, E. A., E-mail: eak@ispms.ru [Institute of Strength Physics and Materials ScienceTomsk, 634055 (Russian Federation); National Research Tomsk Polytechnic University, Tomsk, 634050 (Russian Federation)

    2015-10-27

    This paper deals with structure and properties of aluminum alloy 7475 and its joints obtained by friction stir welding including under ultrasonic action. Microhardness measurements show that ultrasonic action increases strength properties of the joints. Optical and transmission electron microscopy reveals that this effect is related to the precipitation of tertiary coherent S-and T-phase particles.

  9. The general form of the relaxation of a purely interfacial energy for structured deformations

    Czech Academy of Sciences Publication Activity Database

    Šilhavý, Miroslav

    2017-01-01

    Roč. 5, č. 2 (2017), s. 191-215 ISSN 2326-7186 Institutional support: RVO:67985840 Keywords : structured deformations * relaxation * subadditive envelope * interfacial energy Subject RIV: BA - General Mathematics OBOR OECD: Applied mathematics http://msp.org/memocs/2017/5-2/p04.xhtml

  10. Data Structuring and Modeling of Dental Documentation in a Form of Interactive Dental Cross

    Czech Academy of Sciences Publication Activity Database

    Dostálová, T.; Zvárová, Jana; Seydlová, M.; Teuberová, Z.; Pieš, Martin; Hanzlíček, Petr

    2007-01-01

    Roč. 5, č. 3 (2007), s. 288-290 ISSN 1881-4581 R&D Projects: GA AV ČR 1ET200300413 Institutional research plan: CEZ:AV0Z10300504 Keywords : electronic health record * structured data entry Subject RIV: IN - Informatics, Computer Science

  11. Innovative Forms of Regional Structural Policy in Europe: the Role of Dominant Concepts and Knowledge Flows

    NARCIS (Netherlands)

    Lagendijk, A.

    1999-01-01

    The last decade has witnessed a revival of regional structural policy in the Western world. The new style of policy-making which has emerged differs markedly from the top-down distributional models that dominated the post-war period, but is also more pro-active than the hands-off approach of the

  12. Structural Insights into the Quadruplex-Duplex 3' Interface Formed from a Telomeric Repeat: A Potential Molecular Target.

    Science.gov (United States)

    Russo Krauss, Irene; Ramaswamy, Sneha; Neidle, Stephen; Haider, Shozeb; Parkinson, Gary N

    2016-02-03

    We report here on an X-ray crystallographic and molecular modeling investigation into the complex 3' interface formed between putative parallel stranded G-quadruplexes and a duplex DNA sequence constructed from the human telomeric repeat sequence TTAGGG. Our crystallographic approach provides a detailed snapshot of a telomeric 3' quadruplex-duplex junction: a junction that appears to have the potential to form a unique molecular target for small molecule binding and interference with telomere-related functions. This unique target is particularly relevant as current high-affinity compounds that bind putative G-quadruplex forming sequences only rarely have a high degree of selectivity for a particular quadruplex. Here DNA junctions were assembled using different putative quadruplex-forming scaffolds linked at the 3' end to a telomeric duplex sequence and annealed to a complementary strand. We successfully generated a series of G-quadruplex-duplex containing crystals, both alone and in the presence of ligands. The structures demonstrate the formation of a parallel folded G-quadruplex and a B-form duplex DNA stacked coaxially. Most strikingly, structural data reveals the consistent formation of a TAT triad platform between the two motifs. This triad allows for a continuous stack of bases to link the quadruplex motif with the duplex region. For these crystal structures formed in the absence of ligands, the TAT triad interface occludes ligand binding at the 3' quadruplex-duplex interface, in agreement with in silico docking predictions. However, with the rearrangement of a single nucleotide, a stable pocket can be produced, thus providing an opportunity for the binding of selective molecules at the interface.

  13. Structure and interactions of a malarial vaccine candidate, AMA1, form the parasite plasmodium falciparum

    International Nuclear Information System (INIS)

    Miles, L.A.; Keizer, D.W.; Hodder, A.N.; Nair, M.; Hinds, M.G.; Norton, R.S.; Li, F.; Foley, M.; Coley, A.; Anders, R.F.

    2001-01-01

    Full text: Apical membrane antigen 1 (AMA1), a merozoite surface protein found in all species of Plasmodium and other apicomplexan parasites, is a strong candidate for inclusion in a malarial vaccine. Recombinant AMA1 protected against P. fragile in monkeys and P. chabaudi adami in mice. P. falciparum AMA1 which has a 62-kDa ectodomain consisting of three disulphide-stabilised domains, is a target of antibodies that inhibit merozoite invasion in vitro. Here we describe the solution structure of domain III (14 kDa), determined by NMR on 15 N- and 13 C/ 15 N-labelled samples. It has a well-defined disulphide-stabilised core interrupted by a disordered loop, and both the N- and C-terminal regions of the molecule are unstructured. The structured region includes all three disulphide bonds. Naturally-occurring mutations across 11 different P falciparum strains that are located far apart in the sequence cluster around the disulphide core in the 3D structure of domain III, suggesting that this region contains the major epitopes recognised by neutralising antibodies. Consistent with this, the disulphide-bond stabilised conformation of the ectodomain was essential for protection, as the antigen was not an effective vaccine after reduction and alkylation. Peptides have been found by phage display that bind to AMA1 and block merozoite invasion of erythrocytes. We have investigated their solution structures and interaction with full-length AMA1 ectodomain in an effort to understand the structure-function relationships of this important vaccine candidate

  14. Closed-form critical earthquake response of elastic-plastic structures on compliant ground under near-fault ground motions

    Directory of Open Access Journals (Sweden)

    Kotaro eKojima

    2016-01-01

    Full Text Available The double impulse is introduced as a substitute of the fling-step near-fault ground motion. A closed-form solution of the elastic-plastic response of a structure on compliant (flexible ground by the ‘critical double impulse’ is derived for the first time based on the solution for the corresponding structure with fixed base. As in the case of fixed-base model, only the free-vibration appears under such double impulse and the energy approach plays an important role in the derivation of the closed-form solution of a complicated elastic-plastic response on compliant ground. It is remarkable that no iteration is needed in the derivation of the critical elastic-plastic response. It is shown via the closed-form expression that, in the case of a smaller input level of double impulse to the structural strength, as the ground stiffness becomes larger, the maximum plastic deformation becomes larger. On the other hand, in the case of a larger input level of double impulse to the structural strength, as the ground stiffness becomes smaller, the maximum plastic deformation becomes larger. The criticality and validity of the proposed theory are investigated through the comparison with the response analysis to the corresponding one-cycle sinusoidal input as a representative of the fling-step near-fault ground motion. The applicability of the proposed theory to actual recorded pulse-type ground motions is also discussed.

  15. Structure analysis of aluminium silicon manganese nitride precipitates formed in grain-oriented electrical steels

    International Nuclear Information System (INIS)

    Bernier, Nicolas; Xhoffer, Chris; Van De Putte, Tom; Galceran, Montserrat; Godet, Stéphane

    2013-01-01

    We report a detailed structural and chemical characterisation of aluminium silicon manganese nitrides that act as grain growth inhibitors in industrially processed grain-oriented (GO) electrical steels. The compounds are characterised using energy dispersive X-ray spectrometry (EDX) and energy filtered transmission electron microscopy (EFTEM), while their crystal structures are analysed using X-ray diffraction (XRD) and TEM in electron diffraction (ED), dark-field, high-resolution and automated crystallographic orientation mapping (ACOM) modes. The chemical bonding character is determined using electron energy loss spectroscopy (EELS). Despite the wide variation in composition, all the precipitates exhibit a hexagonal close-packed (h.c.p.) crystal structure and lattice parameters of aluminium nitride. The EDX measurement of ∼ 900 stoichiometrically different precipitates indicates intermediate structures between pure aluminium nitride and pure silicon manganese nitride, with a constant Si/Mn atomic ratio of ∼ 4. It is demonstrated that aluminium and silicon are interchangeably precipitated with the same local arrangement, while both Mn 2+ and Mn 3+ are incorporated in the h.c.p. silicon nitride interstitial sites. The oxidation of the silicon manganese nitrides most likely originates from the incorporation of oxygen during the decarburisation annealing process, thus creating extended planar defects such as stacking faults and inversion domain boundaries. The chemical composition of the inhibitors may be written as (AlN) x (SiMn 0.25 N y O z ) 1−x with x ranging from 0 to 1. - Highlights: • We study the structure of (Al,Si,Mn)N inhibitors in grain oriented electrical steels. • Inhibitors have the hexagonal close-packed symmetry with lattice parameters of AlN. • Inhibitors are intermediate structures between pure AlN and (Si,Mn)N with Si/Mn ∼ 4. • Al and Si share the same local arrangement; Mn is incorporated in both Mn 2+ and Mn 3+ . • Oxygen

  16. Isolation and structural elucidation of tiamulin metabolites formed in liver microsomes of pigs

    DEFF Research Database (Denmark)

    Lykkeberg, Anne Kruse; Cornett, Claus; Halling-Sørensen, Bent

    2006-01-01

    Although the antimicrobial tiamulin is extensively metabolized in pigs, the metabolism is not well investigated. In this work the NADPH dependent metabolism of tiamulin in liver microsomes from pigs has been studied. The tiamulin metabolites formed in the incubations were analysed using LC-MS, an...... 20% of tiamulin was deethylated, 10% was hydroxylated in the 2beta-position and 7% was hydroxylated in the 8alpha-position. About 40% of tiamulin was metabolized during the incubation conditions used. The protein precipitation in the incubations was performed using perchloric acid...

  17. [Incidence of anaplastic tumor in structure of other histologic forms of the thyroid gland cancer].

    Science.gov (United States)

    Vinnik, Iu A; Gorbenko, V N; Vas'ko, A R; Kikhtenko, E V; Gargin, V V

    2014-01-01

    The degrees of invasiveness, proliferative activity, morphofunctional activity of nuclei in the thyroidal gland tumors were studied, while analyzing material, obtained in 1343 patients, suffering thyroidal gland cancer (THGC) and operated on in 2000-2013 yrs. Morphological point quantity of malignancy (as a criterion of the tumor progression grade) and mitotic activity in cellular population were determined in various kinds of THGC. Undifferentiated (anaplastic carcinoma) type of THGC is the most malignant one. There were determined a spindle-like, giant-cell and squamous-cell forms of undifferentiated THGC. The presence of sites of differentiated cancer in 33% of histological preparations witnesses the interrelationship with the earlier existed pathological process.

  18. Extreme value predictions and critical wave episodes for marine structures by FORM

    DEFF Research Database (Denmark)

    Jensen, Jørgen Juncher

    2007-01-01

    The aim of the present paper is to advocate for a very effective stochastic procedure, based on the First Order Reliability Method (FORM), for extreme value predictions related to wave induced loads. Three different applications will be illustrated. The first deals with a jack-up rig where second...... order stochastic waves are included in the analysis. The second application is parametric roll motions of ships. Finally, the motion of a TLP floating foundation for an offshore wind turbine is analysed taking into account large motions....

  19. Extreme value predictions and critical wave episodes for marine structures by FORM

    DEFF Research Database (Denmark)

    Jensen, Jørgen Juncher

    2008-01-01

    The aim of the present paper is to advocate for a very effective stochastic procedure, based on the First Order Reliability Method (FORM), for extreme value predictions related to wave induced loads. Three different applications will be illustrated. The first deals with a jack-up rig where second...... order stochastic waves are included in the analysis. The second application is parametric roll motions of ships. Finally, the motion of a TLP floating foundation for an offshore wind turbine is analysed taking into account large motions....

  20. Tubular House - Form Follows Technology, Concrete Shell Structure with Inner Thermal Insulation

    Science.gov (United States)

    Idem, Robert; Kleczek, Paweł; Pawłowski, Krzysztof; Chudoba, Piotr

    2017-10-01

    The aim of this paper is the theoretical analysis of the possibilities and limitations of using an unconventional technology and the original architectural form stemming from it - the building with external construction and internal insulation. In Central European climatic conditions, the traditional solution for the walls of heated buildings relies on using external thermal insulation. This stems from building physics: it prevents interstitial condensation of water vapour in the wall. Internal insulation is used exceptionally. This is done e.g. in historical buildings undergoing thermal modernization (due to the impossibility of interfering with facade). In such cases, a thermal insulation layer is used on the internal wall surface, along with an additional layer of vapour barrier. The concept of building concerns the intentional usage of an internal insulation. In this case, the construction is a tight external reinforced concrete shell. The architectural form of such building is strongly interrelated with the technology, which was used to build it. The paper presents the essence of this concept in descriptive and drawing form. The basic elements of such building are described (the external construction, the internal insulation and ventilation). As a case study, authors present a project of a residential building along with the description of the applied materials and installation solutions, and the results obtained from thermal, humidity and energetic calculations. The discussion presents the advantages and disadvantages of the proposed concept. The basic advantage of this solution is potentially low building cost. This stems from minimizing the ground works, the simplicity of the joints and the outer finish, as well as from the possibility of prefabrication of the elements. The continuity of the thermal insulation allows to reduce the amount of thermal bridges. The applied technology and form are applicable most of all for small buildings, due to limited

  1. Reproducible and recyclable SERS substrates: Flower-like Ag structures with concave surfaces formed by electrodeposition

    Science.gov (United States)

    Bian, Juncao; Shu, Shiwei; Li, Jianfu; Huang, Chao; Li, Yang Yang; Zhang, Rui-Qin

    2015-04-01

    Direct synthesis of three-dimensional Ag structures on solid substrates for the purposes of producing reproducible and recyclable surface-enhanced Raman scattering (SERS) applications remains challenging. In this work, flower-like Ag structures with concave surfaces (FACS) were successfully electrodeposited onto ITO glass using the double-potentiostatic method. The FACS, with an enhancement factor of the order of 108, exhibited a SERS signal intensity 3.3 times stronger than that measured from Ag nanostructures without concave surfaces. A cleaning procedure involving lengthy immersion of the sample in ethanol and KNO3 was proposed to recycle the substrate and confirmed by using rhodamine 6G, adenine, and 4-aminothiophenol as target molecules. The findings can help to advance the practical applications of Ag nanostructure-based SERS substrates.

  2. Crystal Structure of Tetragonal Form of La2NiO4+x

    Science.gov (United States)

    Kajitani, Tsuyoshi; Hosoya, Syoichi; Hirabayashi, Makoto; Fukuda, Tsuguo; Onozuka, Takashi

    1989-10-01

    The crystal structure of the title oxide was studied by means of the X-ray and neutron single crystal diffraction measurements. At room temperature, the tetragonal crystal structure is P42/ncm-type (No. 138), which is one of the subgroup of the space group I4/mmm. The lattice parameters of a sample annealed and slowly cooled in oxygen atmosphere from 673 K are a{=}b{=}5.4640(1) Å and c{=}12.6719(2) Å, while the oxygen content, x{=}0.10(4), was determined from obtained neutron data. The title oxide undergoes a tetragonal (P42/ncm)/tetragonal (I4/mmm) phase transition at about 560 K. The transition temperature is almost identical both in the annealed and as-grown crystals.

  3. Crystal structure of the low-temperature forms of cesium and rubidium orthophosphates

    International Nuclear Information System (INIS)

    Voronin, V.I.; Proskurina, N.V.; Goshchitskij, B.N.; Berger, I.F.; Sheptyakov, D.V.; Burmakin, E.I.; Stroev, S.S.; Shekhtman, G.Sh.

    2008-01-01

    Making use of the neutron diffraction data base Rietveld method one for the first time determined and made more clear the crystal structure of the low-temperature modifications of Cs 3 PO 4 cesium and Rb 3 PO 4 rubidium orthophosphates. Cs 3 PO 4 and Rb 3 PO 4 were found to be isostructural one as to K 3 PO 4 . The structure is a rhombic one (Pnma, Z=4 sp.gr.) with the following elementary cell parameters: a = 1.23177(6) nm, b=0.88948(4) nm, c=0.64197(3) nm and a = 1.17362(2) nm, b=0.81046(1) nm, c=0.615167(9) nm for Cs 3 PO 4 and Rb 3 PO 4 respectively [ru

  4. Small angle neutron scattering form polymer melts: structural investigation and phase behaviour

    International Nuclear Information System (INIS)

    Ertugrul, O.

    2004-01-01

    The Small-Angle Neutron Scattering (SANS) techniques have been used to study the structural properties and phase behavior of polymer melts. A model based on Random Phase Approximation (RPA) is proposed to predict the experimental data. By fitting the model to data we could be able to obtain radius of gyration (a measure of size of a polymer) and phase transition for the sample. (author)

  5. Dynamical, structural and chemical heterogeneities in a binary metallic glass-forming liquid

    Science.gov (United States)

    Puosi, F.; Jakse, N.; Pasturel, A.

    2018-04-01

    As it approaches the glass transition, particle motion in liquids becomes highly heterogeneous and regions with virtually no mobility coexist with liquid-like domains. This complex dynamic is believed to be responsible for different phenomena including non-exponential relaxation and the breakdown of the Stokes-Einstein relation. Understanding the relationships between dynamical heterogeneities and local structure in metallic liquids and glasses is a major scientific challenge. Here we use classical molecular dynamics simulations to study the atomic dynamics and microscopic structure of Cu50Zr50 alloy in the supercooling regime. Dynamical heterogeneities are identified via an isoconfigurational analysis. We demonstrate the transition from isolated to clustering low mobility with decreasing temperature. These slow clusters, whose sizes grow upon cooling, are also associated with concentration fluctuations, characterized by a Zr-enriched phase, with a composition CuZr2 . In addition, a structural analysis of slow clusters based on Voronoi tessellation evidences an increase with respect of the bulk system of the fraction of Cu atoms having a local icosahedral order. These results are in agreement with the consolidated scenario of the relevant role played by icosahedral order in the dynamic slowing-down in supercooled metal alloys.

  6. Hybrid structures formed by homo- and heteroleptic aliphatic dicarboxylates of lead with 2-D inorganic connectivity

    International Nuclear Information System (INIS)

    Thirumurugan, A.; Rao, C.N.R.

    2008-01-01

    Three-dimensional homoleptic (single type of ligand) lead dicarboxylates with hybrid structures involving Pb-O-Pb linkages of the compositions, Pb(C 5 H 6 O 4 ), I, and Pb(C 6 H 8 O 4 ), II and III, have been synthesized and characterized. Three-dimensional heteroleptic (mixed ligands) lead dicarboxylates of the formulae, Pb 2 (C 2 O 4 )(C 4 H 4 O 4 ), IV and Pb 2 (C 2 O 4 )(C 6 H 8 O 4 ), V, with hybrid structures involving Pb-O-Pb linkages have also been prepared and characterized along with a novel two-dimensional lead nitrate-oxalate of the composition, (OPb 2 ) 2 (C 2 O 4 )(NO 3 ) 2 , VI. In all these dicarboxylates, there is two-dimensional inorganic connectivity and the lead (II) cation has hemi- or holo-directed coordination geometry. Depending upon the torsional angle and the coordination mode of the dicarboxylate anions as well as the geometry of the lead (II) cations, these hybrid compounds exhibit two types of two-dimensional inorganic connectivities. - Graphical abstract: Three homoleptic and two heteroleptic three-dimensional lead aliphatic dicarboxylates along with a novel two-dimensional lead nitrate-oxalate with hybrid structures involving Pb-O-Pb linkages have been synthesized and charecterized. In all these dicarboxylates, there is two-dimensional inorganic connectivity. The lead (II) cation has hemi- or holo-directed coordination geometry

  7. Plate-impact loading of cellular structures formed by selective laser melting

    International Nuclear Information System (INIS)

    Winter, R E; Cotton, M; Harris, E J; Maw, J R; Chapman, D J; Eakins, D E; McShane, G

    2014-01-01

    Porous materials are of great interest because of improved energy absorption over their solid counterparts. Their properties, however, have been difficult to optimize. Additive manufacturing has emerged as a potential technique to closely define the structure and properties of porous components, i.e. density, strut width and pore size; however, the behaviour of these materials at very high impact energies remains largely unexplored. We describe an initial study of the dynamic compression response of lattice materials fabricated through additive manufacturing. Lattices consisting of an array of intersecting stainless steel rods were fabricated into discs using selective laser melting. The resulting discs were impacted against solid stainless steel targets at velocities ranging from 300 to 700 m s −1 using a gas gun. Continuum CTH simulations were performed to identify key features in the measured wave profiles, while 3D simulations, in which the individual cells were modelled, revealed details of microscale deformation during collapse of the lattice structure. The validated computer models have been used to provide an understanding of the deformation processes in the cellular samples. The study supports the optimization of cellular structures for application as energy absorbers. (paper)

  8. Modelling size and structure of nanoparticles formed from drying of submicron solution aerosols

    International Nuclear Information System (INIS)

    Bandyopadhyay, Arpan A.; Pawar, Amol A.; Venkataraman, Chandra; Mehra, Anurag

    2015-01-01

    Drying of submicron solution aerosols, under controlled conditions, has been explored to prepare nanoparticles for drug delivery applications. A computational model of solution drop evaporation is developed to study the evolution of solute gradients inside the drop and predict the size and shell thickness of precipitating nanoparticles. The model considers evaporation as a two-stage process involving droplet shrinkage and shell growth. It was corroborated that droplet evaporation rate controls the solute distribution within a droplet and the resulting particle structure (solid or shell type). At higher gas temperatures, rapid build-up of solute near drop surface from high evaporation rates results in early attainment of critical supersaturation solubility and a steeper solute gradient, which favours formation of larger, shell-type particles. At lower gas temperatures, formation of smaller, solid nanoparticles is indicated. The computed size and shell thickness are in good agreement with experimentally prepared lipid nanoparticles. This study indicates that solid or shell structure of precipitated nanoparticles is strongly affected by evaporation rate, while initial solute concentration in the precursor solution and atomized droplet size affect shell thickness. For the gas temperatures considered, evaporative cooling leads to droplet temperature below the melting point of the lipid solute. Thus, we conclude that control over nanoparticle size and structure, of thermolabile precursor materials suitable for drug delivery, can be achieved by controlling evaporation rates, through selection of aerosol processing conditions

  9. Modelling size and structure of nanoparticles formed from drying of submicron solution aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Bandyopadhyay, Arpan A.; Pawar, Amol A.; Venkataraman, Chandra; Mehra, Anurag, E-mail: mehra@iitb.ac.in [Indian Institute of Technology Bombay, Department of Chemical Engineering (India)

    2015-01-15

    Drying of submicron solution aerosols, under controlled conditions, has been explored to prepare nanoparticles for drug delivery applications. A computational model of solution drop evaporation is developed to study the evolution of solute gradients inside the drop and predict the size and shell thickness of precipitating nanoparticles. The model considers evaporation as a two-stage process involving droplet shrinkage and shell growth. It was corroborated that droplet evaporation rate controls the solute distribution within a droplet and the resulting particle structure (solid or shell type). At higher gas temperatures, rapid build-up of solute near drop surface from high evaporation rates results in early attainment of critical supersaturation solubility and a steeper solute gradient, which favours formation of larger, shell-type particles. At lower gas temperatures, formation of smaller, solid nanoparticles is indicated. The computed size and shell thickness are in good agreement with experimentally prepared lipid nanoparticles. This study indicates that solid or shell structure of precipitated nanoparticles is strongly affected by evaporation rate, while initial solute concentration in the precursor solution and atomized droplet size affect shell thickness. For the gas temperatures considered, evaporative cooling leads to droplet temperature below the melting point of the lipid solute. Thus, we conclude that control over nanoparticle size and structure, of thermolabile precursor materials suitable for drug delivery, can be achieved by controlling evaporation rates, through selection of aerosol processing conditions.

  10. Synthesis and new structure shaping mechanism of silica particles formed at high pH

    International Nuclear Information System (INIS)

    Zhang, Henan; Zhao, Yu; Akins, Daniel L.

    2012-01-01

    For the sol–gel synthesis of silica particles under high pH catalytic conditions (pH>12) in water/ethanol solvent, we have deduced that the competing dynamics of chemical etching and sol–gel process can explain the types of silica particles formed and their morphologies. We have demonstrated that emulsion droplets that are generated by adding tetraethyl orthosilicate (TEOS) to a water–ethanol solution serve as soft templates for hollow spherical silica (1–2 μm). And if the emulsion is converted by the sol–gel process, one finds that suspended solid silica spheres of diameter of ∼900 nm are formed. Moreover, several other factors are found to play fundamental roles in determining the final morphologies of silica particles, such as by variation of the pH (in our case, using OH – ) to a level where condensation dominates; by changing the volume ratios of water/ethanol; and using an emulsifier (specifically, CTAB) - Graphical abstract: “Local chemical etching” and sol–gel process have been proposed to interpret the control of morphologies of silica particles through varying initial pHs in syntheses. Highlights: ► Different initial pHs in our syntheses provides morphological control of silica particles. ► “Local chemical etching” and sol–gel process describes the formation of silica spheres. ► The formation of emulsions generates hollow silica particles.

  11. Structural study of anodic films formed on aluminum in nitric acid electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Yakovleva, N.M.; Anicai, L.; Yakovlev, A.N.; Dima, L.; Khanina, E.Ya.; Buda, M.; Chupakhina, E.A

    2002-09-02

    The paper presents the results of investigations of porous Al anodic films formed in HNO{sub 3} electrolytes carried out by means of electrochemical techniques and X-ray diffraction as well as scanning electron microscopy (SEM). It was assumed that both electrochemical formation of a porous oxide and anodic dissolution of metal take place at Al/oxide interface at the same time. The analysis of short-range order (SRO) parameters for relatively high current density, 1x10{sup 3} A/m{sup 2}, and anodizing time, 10 min, leads to the conclusion that films mainly consist of amorphous alumina with {gamma}'-Al{sub 2}O{sub 3}-like SRO and a small amount ({approx}10%) of amorphous aluminum oxyhydroxide. SEM investigation of the films revealed strong dependence of the surface relief on different applied forming conditions. This marked change in the surface relief is discussed taking into account the relatively complex behavior of Al during anodization in HNO{sub 3} electrolytes, that involves both electrochemical growth and dissolution processes of anodic film associated with an electrochemical dissolution of aluminum substrate.

  12. Structural study of anodic films formed on aluminum in nitric acid electrolyte

    International Nuclear Information System (INIS)

    Yakovleva, N.M.; Anicai, L.; Yakovlev, A.N.; Dima, L.; Khanina, E.Ya.; Buda, M.; Chupakhina, E.A.

    2002-01-01

    The paper presents the results of investigations of porous Al anodic films formed in HNO 3 electrolytes carried out by means of electrochemical techniques and X-ray diffraction as well as scanning electron microscopy (SEM). It was assumed that both electrochemical formation of a porous oxide and anodic dissolution of metal take place at Al/oxide interface at the same time. The analysis of short-range order (SRO) parameters for relatively high current density, 1x10 3 A/m 2 , and anodizing time, 10 min, leads to the conclusion that films mainly consist of amorphous alumina with γ'-Al 2 O 3 -like SRO and a small amount (∼10%) of amorphous aluminum oxyhydroxide. SEM investigation of the films revealed strong dependence of the surface relief on different applied forming conditions. This marked change in the surface relief is discussed taking into account the relatively complex behavior of Al during anodization in HNO 3 electrolytes, that involves both electrochemical growth and dissolution processes of anodic film associated with an electrochemical dissolution of aluminum substrate

  13. A structural study of lamellar phases formed by nucleoside-functionalized lipids

    Energy Technology Data Exchange (ETDEWEB)

    Berti, D.; Fratini, E.; Baglioni, P. [Department of Chemistry and CSGI, University of Florence, Via G. Capponi 9, 50121 Florence (Italy); Dante, S.; Hauss, T. [Berlin Neutron Scattering Center, Hahn Meitner Institut, Glienicker Strasse 100, Wannsee, 14109 Berlin (Germany)

    2002-07-01

    We report a neutron-scattering investigation of lamellar phases formed by novel phospholipids bearing nucleosides at the polar-head-group region. These nucleolipids can interact through stacking and H-bond interactions, following a pattern that resembles base-base coupling in natural nucleic acids (DNA, RNA), i.e. they have similar recognition properties. Bilayer stacks formed of DPP-adenosine, DPP-uridine and their 1:1 mixture were investigated after equilibration in a 98% relative humidity atmosphere. The DPP-adenosine spectrum can be accounted for (in analogy to DPPC) by a lamellar phase with a smectic period of about 60 A. DPP-uridine displays a not so straightforward behavior that we have tentatively ascribed to the coexistence of lamellae with different smectic periods. In the 1:1 mixture the lamellar mesophase of DPP-uridine is retained, suggesting a specific interaction of the uridine polar-head group with the adenosine moiety of DPP-adenosine. It should be stressed that this behavior can be considered as an indication of the recognition process occurring at the polar-head-group region of the mixed phospholiponucleoside membrane. (orig.)

  14. Structural aspects of fish skin collagen which forms ordered arrays via liquid crystalline states.

    Science.gov (United States)

    Giraud-Guille, M M; Besseau, L; Chopin, C; Durand, P; Herbage, D

    2000-05-01

    The ability of acid-soluble type I collagen extracts from Soleidae flat fish to form ordered arrays in condensed phases has been compared with data for calf skin collagen. Liquid crystalline assemblies in vitro are optimized by preliminary treatment of the molecular population with ultrasounds. This treatment requires the stability of the fish collagen triple helicity to be controlled by X-ray diffraction and differential scanning calorimetry and the effect of sonication to be evaluated by viscosity measurements and gel electrophoresis. The collagen solution in concentrations of at least 40 mg ml(-1) showed in polarized light microscopy birefringent patterns typical of precholesteric phases indicating long-range order within the fluid collagen phase. Ultrastructural data, obtained after stabilization of the liquid crystalline collagen into a gelated matrix, showed that neutralized acid-soluble fish collagen forms cross-striated fibrils, typical of type I collagen, following sine wave-like undulations in precholesteric domains. These ordered geometries, approximating in vivo situations, give interesting mechanical properties to the material.

  15. A structural study of lamellar phases formed by nucleoside-functionalized lipids

    CERN Document Server

    Berti, D; Baglioni, P; Dante, S; Hauss, T

    2002-01-01

    We report a neutron-scattering investigation of lamellar phases formed by novel phospholipids bearing nucleosides at the polar-head-group region. These nucleolipids can interact through stacking and H-bond interactions, following a pattern that resembles base-base coupling in natural nucleic acids (DNA, RNA), i.e. they have similar recognition properties. Bilayer stacks formed of DPP-adenosine, DPP-uridine and their 1:1 mixture were investigated after equilibration in a 98% relative humidity atmosphere. The DPP-adenosine spectrum can be accounted for (in analogy to DPPC) by a lamellar phase with a smectic period of about 60 A. DPP-uridine displays a not so straightforward behavior that we have tentatively ascribed to the coexistence of lamellae with different smectic periods. In the 1:1 mixture the lamellar mesophase of DPP-uridine is retained, suggesting a specific interaction of the uridine polar-head group with the adenosine moiety of DPP-adenosine. It should be stressed that this behavior can be considere...

  16. Structural evolution during fragile-to-strong transition in CuZr(Al) glass-forming liquids

    DEFF Research Database (Denmark)

    Zhou, C.; Hu, L.N.; Sun, Q.J.

    2015-01-01

    In the present work, we show experimental evidence for the dynamic fragile-to-strong (F-S) transition in a series of CuZr(Al) glass-forming liquids (GFLs). A detailed analysis of the dynamics of 98 glass-forming liquids indicates that the F-S transition occurs around Tf-s ≈ 1.36 Tg. Using...... the hyperquenching-annealing-x-ray scattering approach, we have observed a three-stage evolution pattern of medium-range ordering (MRO) structures during the F-S transition, indicating a dramatic change of the MRO clusters around Tf-s upon cooling. The F-S transition in CuZr(Al) GFLs is attributed to the competition...... among the MRO clusters composed of different locally ordering configurations. A phenomenological scenario has been proposed to explain the structural evolution from the fragile to the strong phase in the CuZr(Al) GFLs....

  17. Universal divergenceless scaling between structural relaxation and caged dynamics in glass-forming systems.

    Science.gov (United States)

    Ottochian, A; De Michele, C; Leporini, D

    2009-12-14

    On approaching the glass transition, the microscopic kinetic unit spends increasing time rattling in the cage of the first neighbors, whereas its average escape time, the structural relaxation time tau(alpha), increases from a few picoseconds up to thousands of seconds. A thorough study of the correlation between tau(alpha) and the rattling amplitude, expressed by the Debye-Waller factor, was carried out. Molecular-dynamics simulations of both a model polymer system and a binary mixture were performed by varying the temperature, the density rho, the potential and the polymer length to consider the structural relaxation as well as both the rotational and the translation diffusion. The present simulations, together with MD studies on other glassformers, evidence the scaling between the structural relaxation and the caged dynamics. An analytic model of the master curve is developed in terms of two characteristic length scales a(2) (1/2) and sigma(a(2) ) (1/2), pertaining to the distance to be covered by the kinetic unit to reach a transition state. The model does not imply tau(alpha) divergences. The comparison with the experiments supports the numerical evidence over a range of relaxation times as wide as about eighteen orders of magnitude. A comparison with other scaling and correlation procedures is presented. In particular, the density scaling of the length scales a(2) (1/2), sigma(a(2) ) (1/2) proportional to rho(-1/3) is shown to be not supported by the present simulations. The study suggests that the equilibrium and the moderately supercooled states of the glassformers possess key information on the huge slowing-down of their relaxation close to the glass transition. The latter, according to the present simulations, exhibits features consistent with the Lindemann melting criterion and the free-volume model.

  18. ALS-causing profilin-1-mutant forms a non-native helical structure in membrane environments.

    Science.gov (United States)

    Lim, Liangzhong; Kang, Jian; Song, Jianxing

    2017-11-01

    Despite having physiological functions completely different from superoxide dismutase 1 (SOD1), profilin 1 (PFN1) also carries mutations causing amyotrophic lateral sclerosis (ALS) with a striking similarity to that triggered by SOD1 mutants. Very recently, the C71G-PFN1 has been demonstrated to cause ALS by a gain of toxicity and the acceleration of motor neuron degeneration preceded the accumulation of its aggregates. Here by atomic-resolution NMR determination of conformations and dynamics of WT-PFN1 and C71G-PFN1 in aqueous buffers and in membrane mimetics DMPC/DHPC bicelle and DPC micelle, we deciphered that: 1) the thermodynamic destabilization by C71G transforms PFN1 into coexistence with the unfolded state, which is lacking of any stable tertiary/secondary structures as well as restricted ps-ns backbone motions, thus fundamentally indistinguishable from ALS-causing SOD1 mutants. 2) Most strikingly, while WT-PFN1 only weakly interacts with DMPC/DHPC bicelle without altering the native structure, C71G-PFN1 acquires abnormal capacity in strongly interacting with DMPC/DHPC bicelle and DPC micelle, energetically driven by transforming the highly disordered unfolded state into a non-native helical structure, similar to what has been previously observed on ALS-causing SOD1 mutants. Our results imply that one potential mechanism for C71G-PFN1 to initiate ALS might be the abnormal interaction with membranes as recently established for SOD1 mutants. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. STRUCTURAL AND FUNCTIONAL MODEL OF FORMING FUTURE MUSIC TEACHER’S CREATIVE THINKING IN INSTRUMENTAL AND PERFORMING TRAINING

    Directory of Open Access Journals (Sweden)

    Nadiia Lavrentieva

    2016-11-01

    Full Text Available In the article conceptual bases of forming students’ creative thinking in the instrumental and performing activities are revealed, taking current training trends into account. The contradictions between the requirements of society to create favorable conditions to realize future music teachers’ creative potential and current directions of a higher educational establishment to ‘a result”, which causes a specific system of promotion and support students’ value orientations and encourages students to master existing knowledge, algorithms, and performing models, depict the relevant problems of making out the system of the future music teachers’ instrumental and performing training that is aimed at developing their creative thinking. It is noted that while defining such phenomena as creative thinking and cognitive work a great number of scientists emphasizes on the word “create” which means finding and creating something that hasn’t been found in the previous individual or social experience. The aim of the article is to disclose the content and stages of implementing structural and functional model of forming future music teachers’ creative thinking The model is formed as an alternative to information and reproductive approach to training future specialists. The concept model is based on the target of forming future music teachers’ creative and methodological thinking, professional competence, activity and approaches to the students’ training to complete fulfillment of modern needs of professional and music education. The author specifies criteria of structural model of future music teachers’ creative thinking. They are value and motivational, cognitive and educational, action and technological, creative and modulating ones The effectiveness of the future music teachers’ creative thinking in instrumental and performing training depends on the level of forming clear science-based system that has a certain conceptual

  20. Incorporating Structural Health Monitoring in the design of slip formed concrete wind turbine towers

    DEFF Research Database (Denmark)

    Hovgaard, Mads Knude

    , where the development of riskbased inspection for offshore structures has been economically motivated, the economic value added by SHM has been somewhat neglected. With a starting point in the business case of wind turbine towers made of concrete, this thesis sets up the framework for the assessing...... is different which require a different approach. As exact solution is intractable, various approximations using surrogate objective functions from detection theory, filters, decision rules and Limited Memory Influence Diagrams (LIMID) are investigated. The main focus is on damage detection but the value...

  1. Structural and mechanical properties of hydroxyapatite coatings formed by ion-beam assisted deposition

    Science.gov (United States)

    Zykova, A.; Safonov, V.; Dudin, S.; Yakovin, S.; Donkov, N.; Ghaemi, M. H.; Szkodo, M.; Antoszkiewicz, M.; Szyfelbain, M.; Czaban, A.

    2018-03-01

    The ion-beam assisted deposition (IBAD) is an advanced method capable of producing crystalline coatings at low temperatures. We determined the characteristics of hydroxyapatite Ca10(PO4)6(OH)2 target and coatings formed by IBAD using X-ray photoemission spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and energy dispersive X-ray (EDX). The composition of the coatings’ cross-section and surface was close to those of the target. The XPS spectra showed that the binding energy values of Ca (2p1/2, 2p3/2), P (2p3/2), and O 1s levels are related to the hydroxyapatite phase. The coatings demonstrate an optimal H/E ratio, and a good resistance to scratch tests.

  2. Structural studies of formic acid using partial form-factor analysis

    International Nuclear Information System (INIS)

    Swan, G.; Dore, J.C.; Bellissent-Funel, M.C.

    1993-01-01

    Neutron diffraction measurements have been made of liquid formic acid using H/D isotopic substitution. Data are recorded for samples of DCOOD, HCOOD and a (H/D)COOD mixture (α D =0.36). A first-order difference method is used to determine the intra-molecular contribution through the introduction of a partial form-factor analysis technique incorporating a hydrogen-bond term. The method improves the sensitivity of the parameters defining the molecular geometry and avoids some of the ambiguities arising from terms involving spatial overlap of inter- and intra-molecular features. The possible application to other systems is briefly reviewed. (authors). 8 figs., 2 tabs., 8 refs

  3. Reconnaissance de formes moléculaires dans les relations structure-activité

    OpenAIRE

    Mathis , Hervé

    1992-01-01

    Non disponible / Not available; Cette thèse présente un logiciel qui a pour but de mieux comprendre les relations entre caractéristiques structurales et propriétés thérapeutiques de molécules envisagées comme médicaments. L'idée majeure est de soumettre une famille de composés, d'une part à des calculs de chimie quantique, d'autre part à des méthodes de reconnaissance de formes, afin d'observer si certaines propriétés moléculaires sont discriminantes vis-à-vis d'une activité pharmacologique m...

  4. [The electron microscopic observation of the effect of monoclonal antibody on the form and structure of mutans streptococci OMZ176].

    Science.gov (United States)

    Wen, L; Yue, S

    1996-01-01

    The effect of monoclonal antibody on the form and structure of Mutans Streptococci OMZ176 was studied. The result showed that a great number of Mutans Streptococci OMZ176 was agglutianated after treating with monoclonal antibody prepared by a cell wall protein antigen (molecular weight 220 kd) of Mutans Streptococci OMZ176. Bacterial cells were swollen obviously. The gap between cell wall and cytoplasmic was widened. The electronic density of cell plasm was greatly decreased.

  5. Unusual glass-forming ability induced by changes in the local atomic structure in Ti-based bulk metallic glass

    International Nuclear Information System (INIS)

    Kim, Y C; Chang, H J; Kim, D H; Kim, W T; Cha, P R

    2007-01-01

    The effect of partial replacement of Cu by Be in Ti 50 Cu 32 Ni 15 Sn 3 alloy on the thermal properties, structure, and forming ability of an amorphous phase were investigated by differential scanning calorimetry (DSC), x-ray diffraction (XRD), extended x-ray absorption fine structure (EXAFS), and high-resolution transmission electron microscopy (HRTEM). Ti 50 Cu 25 Ni 15 Sn 3 Be 7 alloy shows enhanced glass-forming ability, enabling one to fabricate a fully amorphous bulk metallic glass sample 2 mm in diameter by injection casting. With the replacement, the supercooled liquid region ΔT x (= T x -T g , where T x is the crystallization temperature and T g is the glass transition temperature) decreased from 73 to 45 K and the reduced glass transition temperature T rg (= T g /T 1 , where T 1 is the liquidus temperature) increased from 0.53 to 0.57. The amorphous Ti 50 Cu 25 Ni 15 Sn 3 Be 7 phase showed a formation of short-range-ordered clusters 1-2 nm in size, which is attributed to the strong interaction between Ti and Be. The results show that ΔT x can be used as a thermal parameter reflecting the glass-forming ability of the alloy only when the phase formed during crystallization is the same as the phase competing with the glass transition during solidification

  6. Hydrophobic radical influence on structure and vibration spectra of zwitter-ionic forms of glycine and alanine in condensed state

    International Nuclear Information System (INIS)

    Ten, G.N.; Kadrov, D.M.; Baranov, V.I.

    2014-01-01

    Structure and vibrational spectra of the zwitter-ionic forms of glycine and alanine in water solution and solid state have been calculated in the B3LYP/6-311++G(d,p) approximation. The environment influence has been taken into account by two methods: the self-consistent reaction field (SCRF) method and one of modeling the glycine and alanine complexes with molecules of water. The structure, energy and spectral properties have been determined which allow establishing an influence of the hydrophobic radical on the glycine and alanine ability to form the hydrogen bonds. It is shown by comparison with experiment that for the calculation of vibrational (IR and Raman) spectra of the zwitter-ionic forms of glycine and alanine in the condensed states they must be surrounded with three molecules of water, one of which is located between the N + H 3 and COO - ionic groups. The value of energy necessary to form the Ala complexes with water compared to Gly ones is 56.47 and 12.55 kcal/mol higher in the case of the complex formation with 1and 3 molecules of water, respectively, located between bipolar groups. (authors)

  7. Minicollagen-15, a novel minicollagen isolated from Hydra, forms tubule structures in nematocysts.

    Science.gov (United States)

    Adamczyk, Patrizia; Meier, Sebastian; Gross, Thomas; Hobmayer, Bert; Grzesiek, Stephan; Bächinger, Hans Peter; Holstein, Thomas W; Ozbek, Suat

    2008-02-29

    Minicollagens constitute a family of unusually short collagen molecules isolated from cnidarians. They are restricted to the nematocyst, a cylindrical explosive organelle serving in defense and capture of prey. The nematocyst capsule contains a long tubule inside of its matrix, which is expelled and everted during an ultrafast discharge process. Here, we report the cloning and characterization of a novel minicollagen in Hydra, designated minicollagen-15 (NCol-15). NCol-15, like NCol-3 and NCol-4, shows deviations from the canonical cysteine pattern in its terminal cysteine-rich domains (CRDs). Minicollagens share common domain architectures with a central collagen sequence flanked by polyproline stretches and short N- and C-terminal CRDs. The CRDs are involved in the formation of a highly resistant cysteine network, which constitutes the basic structure of the nematocyst capsule. Unlike NCol-1, which is part of the capsule wall, NCol-15 is localized to tubules, arguing for a functional differentiation of minicollagens within the nematocyst architecture. NMR analysis of the altered C-terminal CRD of NCol-15 showed a novel disulfide-linked structure within the cysteine-containing region exhibiting similar folding kinetics and stability as the canonical CRDs. Our data provide evidence for evolutionary diversification among minicollagens, which probably facilitated alterations in the morphology of the nematocyst wall and tubule.

  8. Structural transitions and hysteresis in clump- and stripe-forming systems under dynamic compression

    International Nuclear Information System (INIS)

    McDermott, Danielle; Reichhardt, Charles

    2016-01-01

    In using numerical simulations, we study the dynamical evolution of particles interacting via competing long-range repulsion and short-range attraction in two dimensions. The particles are compressed using a time-dependent quasi-one dimensional trough potential that controls the local density, causing the system to undergo a series of structural phase transitions from a low density clump lattice to stripes, voids, and a high density uniform state. The compression proceeds via slow elastic motion that is interrupted with avalanche-like bursts of activity as the system collapses to progressively higher densities via plastic rearrangements. The plastic events vary in magnitude from small rearrangements of particles, including the formation of quadrupole-like defects, to large-scale vorticity and structural phase transitions. In the dense uniform phase, the system compresses through row reduction transitions mediated by a disorder-order process. We also characterize the rearrangement events by measuring changes in the potential energy, the fraction of sixfold coordinated particles, the local density, and the velocity distribution. At high confinements, we find power law scaling of the velocity distribution during row reduction transitions. We observe hysteresis under a reversal of the compression when relatively few plastic rearrangements occur. The decompressing system exhibits distinct phase morphologies, and the phase transitions occur at lower compression forces as the system expands compared to when it is compressed.

  9. Interactions between concentric form-from-structure and face perception revealed by visual masking but not adaptation

    Science.gov (United States)

    Feczko, Eric; Shulman, Gordon L.; Petersen, Steven E.; Pruett, John R.

    2014-01-01

    Findings from diverse subfields of vision research suggest a potential link between high-level aspects of face perception and concentric form-from-structure perception. To explore this relationship, typical adults performed two adaptation experiments and two masking experiments to test whether concentric, but not nonconcentric, Glass patterns (a type of form-from-structure stimulus) utilize a processing mechanism shared by face perception. For the adaptation experiments, subjects were presented with an adaptor for 5 or 20 s, prior to discriminating a target. In the masking experiments, subjects saw a mask, then a target, and then a second mask. Measures of discriminability and bias were derived and repeated measures analysis of variance tested for pattern-specific masking and adaptation effects. Results from Experiment 1 show no Glass pattern-specific effect of adaptation to faces; results from Experiment 2 show concentric Glass pattern masking, but not adaptation, may impair upright/inverted face discrimination; results from Experiment 3 show concentric and radial Glass pattern masking impaired subsequent upright/inverted face discrimination more than translational Glass pattern masking; and results from Experiment 4 show concentric and radial Glass pattern masking impaired subsequent face gender discrimination more than translational Glass pattern masking. Taken together, these findings demonstrate interactions between concentric form-from-structure and face processing, suggesting a possible common processing pathway. PMID:24563526

  10. Modelling and simulation of the influence of forming processes on the structural behavior of high strength steels

    International Nuclear Information System (INIS)

    Gelin, J.C.; Thibaud, S.; Boudeau, N.

    2005-01-01

    The paper first describes experiments and modeling concerning the identification of material behavior for high strength steels with phase transformations associated to plastic deformation. The experiments consist of tensile and bulging tests carried out on 316L stainless steels and TRIP 700 steels used in automotive industry. These experiments have permitted to determine the hardening curves of such materials vs. the martensite volume fraction associated to plastic deformation. It has been demonstrated that the stress triaxiality has a major role in the martenstic transformation and a model is proposed to define the flow stress vs. effective strain accounting planar anisotropy and variation of martenstic volume fraction. Then a plasticity model has been proposed in an anisotropic form and the related flow rules have been defined. The resulting model has been implemented in different finite elements software, and applied in numerical simulations of stamping and hydroforming of typical components to prove the effects of forming processes on the resulting properties of the components. Finally, the structural behavior of the resulting components is investigated and the effects of forming processes on the resulting structural behaviour are analyzed. Two cases are presented, one concerns the deep drawing of a cylindrical cup and the other concerns the stamping of a closed U channel used as a structural part for crash frames. Is has been clearly proved that the variation of martensite volume fraction arising during processing has a strong influence on the resulting behaviour of the parts considering springback and crash resistance

  11. Crystal Structures, Thermal Analysis, and Dissolution Behavior of New Solid Forms of the Antiviral Drug Arbidol with Dicarboxylic Acids

    Directory of Open Access Journals (Sweden)

    Alex N. Manin

    2015-12-01

    Full Text Available Salts of the antiviral drug arbidol (umifenovir (Arb with maleate (Mlc and fumarate (Fum anions have been obtained, and their crystal structures have been described. The crystal structure of arbidol maleate has been redetermined by single crystal X-ray diffraction at 180K. A new arbidol cocrystal in zwitterion form with succinic acid (Suc has also been found and characterized. The arbidol zwitterion was not previously seen in any of the drug crystal forms, and the [Arb + Suc] cocrystal seems to be the first found instance. Analysis of the conformational preferences of the arbidol molecule in the crystal structures has shown that it adopts two types of conformations, namely “open” and “closed” ones. Thermal stability of the arbidol salts and cocrystal have been analyzed by means of differential scanning calorimetry, thermogravimetric, and mass-spectrometry analysis. The dissolution study of the arbidol salts and cocrystal performed in aqueous buffer solutions with pH 1.2 and 6.8 has shown that both the salts and the cocrystal dissolve incongruently to form an arbidol hydrochloride monohydrate at pH 1.2 and an arbidol base at pH 6.8, respectively. The cocrystal reaches the highest solubility level in both pH 1.2 and pH 6.8 solutions.

  12. Changes to the structure of blood clots formed in the presence of fine particulate matter

    International Nuclear Information System (INIS)

    Metassan, Sofian; Routledge, Michael N; Ariens, Robert A S; Scott, D Julian

    2009-01-01

    Both long-term and short-term exposure (one to two hours) to particulate matter are associated with morbidity and mortality caused by cardiovascular diseases. The underlying mechanisms leading to cardiovascular events are unclear, however, changes to blood coagulability upon exposure to ultrafine particulate matter (UFPM, the smallest of which can enter the circulation) is a plausible mechanism. Objectives: This study aims to investigate the direct effects of particulate matter on fibrin polymerization, lateral aggregation and the formation of fibrin network structure. Methods: Standard Urban Particulate Matter (PM) was suspended in Tris buffer centrifuged and filtered with <200nm filter to obtain ultrafine PM or their water-soluble components. Purified normal fibrinogen was made to clot by adding thrombin and calcium chloride in the presence of varying concentrations of PM. Permeation properties (Darcy constant [Ks]) and turbidity of clots were measured to investigate the effects on flow-rate, pore size, and fibrin polymerization. In addition, confocal microscopy was performed to study detailed clot structure. Results: Total PM increased the Ks of clots in a dose dependant manner (Ks = 4.4, 6.9 and 13.2 x 10-9 cm2 for 0, 50 and 100 |ag/ml total PM concentrations, respectively). Filtered PM also produced a significant increase in Ks at PM concentration of 17 |ag/ml. Final turbidity measurements at 20min were obtained for varying concentrations of PM. Maximum optical density (OD) for 1 mg/ml fibrinogen at 0, 50, 100 and 200 |ag/ml total PM concentrations were 0.39, 0.42, 0.45 and 0.46, respectively. The maximum OD for 0, 17, 34 and 68 |ag/ml filtered PM concentrations were 0.39, 0.42 0.47 and 0.51, respectively, suggesting an increase in fibre diameter with increasing particulate concentration. The lag phase was significantly shorter and the rate of polymerisation was significantly faster in the presence of 68 |ag/ml filtered PM. Confocal microscopy results showed

  13. Italianization Accomplished. Forms and Structures of Albanian Television’s Dependency on Italian Media and Culture

    Directory of Open Access Journals (Sweden)

    Paolo Carelli

    2014-06-01

    Full Text Available After the fall of the Berlin Wall and the end of communist regimes in 1989, national media systems of the Eastern European countries belonging to the Soviet bloc began a process of transformation along the way of liberalization and commercialization. In Albania, this process occurred in different phases, but with a common trend, that is the Italian television as a structural, economic and cultural model to inspire. In this article, I try to outline the deep influences and legacies between Italian and Albanian television systems (dating back to the last years of the regime showing how, despite a progressive sliding towards americanization, they remain a typical landmark of Albanian media. From the formats of the first programmes after the regime to the recent appearances of Italian Tv presenters (in particular, from Berlusconi's channels on Albanian private channels, we can observe a subtle but rooted and continuous dependency from the country on the other side of the Adriatic Sea.  

  14. Process for growing a film epitaxially upon a MGO surface and structures formed with the process

    Science.gov (United States)

    McKee, Rodney Allen; Walker, Frederick Joseph

    1998-01-01

    A process and structure wherein optical quality perovskites, such as BaTiO.sub.3 or SrTiO.sub.3, are grown upon a single crystal MgO substrate involves the epitaxial build up of alternating planes of TiO.sub.2 and metal oxide wherein the first plane grown upon the MgO substrate is a plane of TiO.sub.2. The layering sequence involved in the film build up reduces problems which would otherwise result from the interfacial electrostatics at the first atomic layers, and these oxides can be stabilized as commensurate thin films at a unit cell thickness or grown with high crystal quality to thicknesses of 0.5-0.7 .mu.m for optical device applications.

  15. The pseudo-Boolean optimization approach to form the N-version software structure

    Science.gov (United States)

    Kovalev, I. V.; Kovalev, D. I.; Zelenkov, P. V.; Voroshilova, A. A.

    2015-10-01

    The problem of developing an optimal structure of N-version software system presents a kind of very complex optimization problem. This causes the use of deterministic optimization methods inappropriate for solving the stated problem. In this view, exploiting heuristic strategies looks more rational. In the field of pseudo-Boolean optimization theory, the so called method of varied probabilities (MVP) has been developed to solve problems with a large dimensionality. Some additional modifications of MVP have been made to solve the problem of N-version systems design. Those algorithms take into account the discovered specific features of the objective function. The practical experiments have shown the advantage of using these algorithm modifications because of reducing a search space.

  16. Composite Films Formed by Cellulose nanocrystals and Latex Nanoparticles: Optical, Structural, and Mechanical Properties

    Science.gov (United States)

    Vollick, Brandon McRae

    This thesis describes the preparation of iridescent, birefringent, composite films composed of cellulose nanocrystals (CNCs), latex nanoparticles (NPs) and a NP crosslinker; hexanediamine (HDA). First, aqueous suspensions were prepared with varying quantities of CNCs, NPs and HDA before equilibrating for one week. The cholesteric (Ch) phase was then cast and dried into a film. The optical, structural and mechanical properties of the film was analyzed. Second, films with identical compositions of CNCs, NPs, and HDA were fabricated in three different ways to yield films of different morphology, (i) fast drying of an isotropic suspension, yielding an isotropic film, (ii) slow drying of an isotropic suspension, yielding a partially Ch films, (iii) slow drying of an equilibrated suspension, yielding a highly Ch film. The optical and mechanical properties of the films was analyzed.

  17. Cold spraying of aluminum bronze on profiled submillimeter cermet structures formed by laser cladding

    Science.gov (United States)

    Ryashin, N. S.; Malikov, A. G.; Shikalov, V. S.; Gulyaev, I. P.; Kuchumov, B. M.; Klinkov, S. V.; Kosarev, V. F.; Orishich, A. M.

    2017-10-01

    The paper presents results of the cold spraying of aluminum bronze coatings on substrates profiled with WC/Ni tracks obtained by laser cladding. Reinforcing cermet frames shaped as grids with varied mesh sizes were clad on stainless steel substrates using a CO2 laser machine "Siberia" (ITAM SB RAS, Russia). As a result, surfaces/substrates with heterogeneous shape, composition, and mechanical properties were obtained. Aluminum bronze coatings were deposited from 5lF-NS powder (Oerlikon Metco, Switzerland) on those substrates using cold spraying equipment (ITAM SB RAS). Data of profiling, microstructure diagnostics, EDS analysis, and mechanical tests of obtained composites is reported. Surface relief of the sprayed coatings dependence on substrate structure has been demonstrated.

  18. Structural aspects of cold-formed steel section designed as U-shape composite beam

    Science.gov (United States)

    Saggaff, Anis; Tahir, Mahmood Md.; Azimi, Mohammadamin; Alhajri, T. M.

    2017-11-01

    Composite beam construction usually associated with old-style Hot-Rolled Steel Section (HRSS) has proven to act much better in compare with Cold-Formed Steel Section (CFSS) sections due to thicker section. Due, it's getting popular to replace HRSS with CFSS in some aspects as a composite beam. The advantages such as lightweight, cost effective and easy to install have contributed to the apply CFSS as a preferred construction material for composite beam. There is a few technical data available regarding the application of the usage of CFSS as a composite system, despite the potentials use for residential and light-weight industrial constructions. This paper presents an experimental tests results which have been conducted using CFSS as composite beam. Composite action of CFSS arranged as double beam with Self-Compacting Concrete (SCC) slab are integrated together with bolted shear connectors were used. A full-scale test comprised of 3 proposed composite beam specimens with bolted shear connector spaced at 300 mm interval of grade 8.8 was using single nut with washer on flange of CFS, cast to the slab and loaded until failed. The test show that the bolted shear connector yielded better capacity of ultimate strength and ultimate moment for the proposed composite beam. It can be concluded that, bolted shear connectors of 16 mm in diameter performed better than the other diameter size of bolted shear connectors.

  19. Chemical structure of the adducts formed by the oxidation of benzidine in the presence of phenols

    International Nuclear Information System (INIS)

    Josephy, P.D.; Mason, R.P.; Eling, T.

    1982-01-01

    Bioactivation of carcinogens by peroxidases has received increasing attention since the discovery of the oxidation of carcinogens by prostaglandin hydroperoxidase. Benzidine and 3,5,3',5'-tetramethylbenzidine are oxidized by horseradish peroxidase and prostaglandin synthase to two-electron oxidation products (di-imines). Di-imines readily react with the phenolic anti-oxidant butylated hydroxyanisole to form adducts. In this paper, we have studied the oxidation of benzidine by horseradish peroxidase in the presence of phenolic compounds and characterized the resultant benzidine/phenol adducts. A benzidine/2,6-dimethylphenol adduct was isolated and characterized by mass spectrometry and high field n.m.r. The reaction of [ 14 C]benzidine in the presence of horseradish peroxidase and phenol yielded only the benzidine/phenol adduct. Our results indicate that the benzidine/phenol adducts are analogous to the indoaniline dyes, differing only in substitution of a biphenyl group for a benzene ring. The reaction of benzidine di-imine with endogenous phenols may represent a new pathway for detoxication, removing potentially harmful metabolites of benzidine

  20. Truncated forms of the prion protein PrP demonstrate the need for complexity in prion structure

    Energy Technology Data Exchange (ETDEWEB)

    Wan, William; Stöhr, Jan; Kendall, Amy; Stubbs, Gerald

    2015-09-01

    Self-propagation of aberrant protein folds is the defining characteristic of prions. Knowing the structural basis of self-propagation is essential to understanding prions and their related diseases. Prion rods are amyloid fibrils, but not all amyloids are prions. Prions have been remarkably intractable to structural studies, so many investigators have preferred to work with peptide fragments, particularly in the case of the mammalian prion protein PrP. We compared the structures of a number of fragments of PrP by X-ray fiber diffraction, and found that although all of the peptides adopted amyloid conformations, only the larger fragments adopted conformations that modeled the complexity of self-propagating prions, and even these fragments did not always adopt the PrP structure. It appears that the relatively complex structure of the prion form of PrP is not accessible to short model peptides, and that self-propagation may be tied to a level of structural complexity unobtainable in simple model systems. The larger fragments of PrP, however, are useful to illustrate the phenomenon of deformed templating (heterogeneous seeding), which has important biological consequences.

  1. Truncated forms of the prion protein PrP demonstrate the need for complexity in prion structure.

    Science.gov (United States)

    Wan, William; Stöhr, Jan; Kendall, Amy; Stubbs, Gerald

    2015-01-01

    Self-propagation of aberrant protein folds is the defining characteristic of prions. Knowing the structural basis of self-propagation is essential to understanding prions and their related diseases. Prion rods are amyloid fibrils, but not all amyloids are prions. Prions have been remarkably intractable to structural studies, so many investigators have preferred to work with peptide fragments, particularly in the case of the mammalian prion protein PrP. We compared the structures of a number of fragments of PrP by X-ray fiber diffraction, and found that although all of the peptides adopted amyloid conformations, only the larger fragments adopted conformations that modeled the complexity of self-propagating prions, and even these fragments did not always adopt the PrP structure. It appears that the relatively complex structure of the prion form of PrP is not accessible to short model peptides, and that self-propagation may be tied to a level of structural complexity unobtainable in simple model systems. The larger fragments of PrP, however, are useful to illustrate the phenomenon of deformed templating (heterogeneous seeding), which has important biological consequences.

  2. Structure of the protein core of translation initiation factor 2 in apo, GTP-bound and GDP-bound forms

    International Nuclear Information System (INIS)

    Simonetti, Angelita; Marzi, Stefano; Fabbretti, Attilio; Hazemann, Isabelle; Jenner, Lasse; Urzhumtsev, Alexandre; Gualerzi, Claudio O.; Klaholz, Bruno P.

    2013-01-01

    The crystal structures of the eubacterial translation initiation factor 2 in apo form and with bound GDP and GTP reveal conformational changes upon nucleotide binding and hydrolysis, notably of the catalytically important histidine in the switch II region. Translation initiation factor 2 (IF2) is involved in the early steps of bacterial protein synthesis. It promotes the stabilization of the initiator tRNA on the 30S initiation complex (IC) and triggers GTP hydrolysis upon ribosomal subunit joining. While the structure of an archaeal homologue (a/eIF5B) is known, there are significant sequence and functional differences in eubacterial IF2, while the trimeric eukaryotic IF2 is completely unrelated. Here, the crystal structure of the apo IF2 protein core from Thermus thermophilus has been determined by MAD phasing and the structures of GTP and GDP complexes were also obtained. The IF2–GTP complex was trapped by soaking with GTP in the cryoprotectant. The structures revealed conformational changes of the protein upon nucleotide binding, in particular in the P-loop region, which extend to the functionally relevant switch II region. The latter carries a catalytically important and conserved histidine residue which is observed in different conformations in the GTP and GDP complexes. Overall, this work provides the first crystal structure of a eubacterial IF2 and suggests that activation of GTP hydrolysis may occur by a conformational repositioning of the histidine residue

  3. Structure of the protein core of translation initiation factor 2 in apo, GTP-bound and GDP-bound forms

    Energy Technology Data Exchange (ETDEWEB)

    Simonetti, Angelita [IGBMC (Institute of Genetics and of Molecular and Cellular Biology), Centre National de la Recherche Scientifique (CNRS) UMR 7104/Institut National de la Santé de la Recherche Médicale - INSERM U964/Université de Strasbourg, 1 Rue Laurent Fries, 67404 Illkirch (France); Marzi, Stefano [Architecture et Réactivité de l’ARN, UPR 9002 CNRS, IBMC (Institute of Molecular and Cellular Biology), 15 Rue R. Descartes, 67084 Strasbourg, France, Université de Strasbourg, 67000 Strasbourg (France); Fabbretti, Attilio [University of Camerino, 62032 Camerino (Monaco) (Italy); Hazemann, Isabelle; Jenner, Lasse [IGBMC (Institute of Genetics and of Molecular and Cellular Biology), Centre National de la Recherche Scientifique (CNRS) UMR 7104/Institut National de la Santé de la Recherche Médicale -INSERM U964/Université de Strasbourg, 1 Rue Laurent Fries, 67404 Illkirch (France); Urzhumtsev, Alexandre [IGBMC (Institute of Genetics and of Molecular and Cellular Biology), Centre National de la Recherche Scientifique (CNRS) UMR 7104/Institut National de la Santé de la Recherche Médicale - INSERM U964/Université de Strasbourg, 1 Rue Laurent Fries, 67404 Illkirch (France); Université de Lorraine, 54506 Vandoeuvre-lès-Nancy (France); Gualerzi, Claudio O. [University of Camerino, 62032 Camerino (Monaco) (Italy); Klaholz, Bruno P., E-mail: klaholz@igbmc.fr [IGBMC (Institute of Genetics and of Molecular and Cellular Biology), Centre National de la Recherche Scientifique (CNRS) UMR 7104/Institut National de la Santé de la Recherche Médicale - INSERM U964/Université de Strasbourg, 1 Rue Laurent Fries, 67404 Illkirch (France)

    2013-06-01

    The crystal structures of the eubacterial translation initiation factor 2 in apo form and with bound GDP and GTP reveal conformational changes upon nucleotide binding and hydrolysis, notably of the catalytically important histidine in the switch II region. Translation initiation factor 2 (IF2) is involved in the early steps of bacterial protein synthesis. It promotes the stabilization of the initiator tRNA on the 30S initiation complex (IC) and triggers GTP hydrolysis upon ribosomal subunit joining. While the structure of an archaeal homologue (a/eIF5B) is known, there are significant sequence and functional differences in eubacterial IF2, while the trimeric eukaryotic IF2 is completely unrelated. Here, the crystal structure of the apo IF2 protein core from Thermus thermophilus has been determined by MAD phasing and the structures of GTP and GDP complexes were also obtained. The IF2–GTP complex was trapped by soaking with GTP in the cryoprotectant. The structures revealed conformational changes of the protein upon nucleotide binding, in particular in the P-loop region, which extend to the functionally relevant switch II region. The latter carries a catalytically important and conserved histidine residue which is observed in different conformations in the GTP and GDP complexes. Overall, this work provides the first crystal structure of a eubacterial IF2 and suggests that activation of GTP hydrolysis may occur by a conformational repositioning of the histidine residue.

  4. Detection of the electronic structure of iron-(iii)-oxo oligomers forming in aqueous solutions.

    Science.gov (United States)

    Seidel, Robert; Kraffert, Katrin; Kabelitz, Anke; Pohl, Marvin N; Kraehnert, Ralph; Emmerling, Franziska; Winter, Bernd

    2017-12-13

    The nature of the small iron-oxo oligomers in iron-(iii) aqueous solutions has a determining effect on the chemical processes that govern the formation of nanoparticles in aqueous phase. Here we report on a liquid-jet photoelectron-spectroscopy experiment for the investigation of the electronic structure of the occurring iron-oxo oligomers in FeCl 3 aqueous solutions. The only iron species in the as-prepared 0.75 M solution are Fe 3+ monomers. Addition of NaOH initiates Fe 3+ hydrolysis which is followed by the formation of iron-oxo oligomers. At small enough NaOH concentrations, corresponding to approximately [OH]/[Fe] = 0.2-0.25 ratio, the iron oligomers can be stabilized for several hours without engaging in further aggregation. Here, we apply a combination of non-resonant as well as iron 2p and oxygen 1s resonant photoelectron spectroscopy from a liquid microjet to detect the electronic structure of the occurring species. Specifically, the oxygen 1s partial electron yield X-ray absorption (PEY-XA) spectra are found to exhibit a peak well below the onset of liquid water and OH - (aq) absorption. The iron 2p absorption gives rise to signal centered between the main absorption bands typical for aqueous Fe 3+ . Absorption bands in both PEY-XA spectra are found to correlate with an enhanced photoelectron peak near 20 eV binding energy, which demonstrates the sensitivity of resonant photoelectron (RPE) spectroscopy to mixing between iron and ligand orbitals. These various signals from the iron-oxo oligomers exhibit maximum intensity at [OH]/[Fe] = 0.25 ratio. For the same ratio, we observe changes in the pH as well as in complementary Raman spectra, which can be assigned to the transition from monomeric to oligomeric species. At approximately [OH]/[Fe] = 0.3 we begin to observe particles larger than 1 nm in radius, detected by small-angle X-ray scattering.

  5. Neural Integration of Information Specifying Human Structure from Form, Motion, and Depth

    Science.gov (United States)

    Jackson, Stuart; Blake, Randolph

    2010-01-01

    Recent computational models of biological motion perception operate on ambiguous two-dimensional representations of the body (e.g., snapshots, posture templates) and contain no explicit means for disambiguating the three-dimensional orientation of a perceived human figure. Are there neural mechanisms in the visual system that represent a moving human figure’s orientation in three dimensions? To isolate and characterize the neural mechanisms mediating perception of biological motion, we used an adaptation paradigm together with bistable point-light (PL) animations whose perceived direction of heading fluctuates over time. After exposure to a PL walker with a particular stereoscopically defined heading direction, observers experienced a consistent aftereffect: a bistable PL walker, which could be perceived in the adapted orientation or reversed in depth, was perceived predominantly reversed in depth. A phase-scrambled adaptor produced no aftereffect, yet when adapting and test walkers differed in size or appeared on opposite sides of fixation aftereffects did occur. Thus, this heading direction aftereffect cannot be explained by local, disparity-specific motion adaptation, and the properties of scale and position invariance imply higher-level origins of neural adaptation. Nor is disparity essential for producing adaptation: when suspended on top of a stereoscopically defined, rotating globe, a context-disambiguated “globetrotter” was sufficient to bias the bistable walker’s direction, as were full-body adaptors. In sum, these results imply that the neural signals supporting biomotion perception integrate information on the form, motion, and three-dimensional depth orientation of the moving human figure. Models of biomotion perception should incorporate mechanisms to disambiguate depth ambiguities in two-dimensional body representations. PMID:20089892

  6. A infância enquanto categoria estrutural Childhood as a structural form

    Directory of Open Access Journals (Sweden)

    Jens Qvortrup

    2010-08-01

    tenham como objeto a infância como categoria social, portanto diversa e complementar às outras categorias. A leitura do texto remete a outros temas, tratados por diferentes autores nos demais capítulos, o que faz os pesquisadores brasileiros almejarem a tradução integral do livro.In northern countries, a symbol of the consolidation of a knowledge area is the publication of a handbook - in Portuguese, manual or compendium - whose chapters give a state-of-the-art overview of their respective subjects. In 2009, The Palgrave Handbook of Childhood Studies was published as recognition of the area of childhood studies. It is known that children were mainly investigated by psychology or by pedagogy and that social sciences have produced little about them, giving priority to studies on the family or the school. Just over twenty years, however, children become the focus of social studies of childhood, as social phenomenon. In this sense, there is the field that investigates children as social agents, producing culture, and childhood as category in the social structure, which increased significantly the production of knowledge about the social relations established between the children themselves (their peers and with adults (intra and intergenerational relations on their skills as actors in their lives, as social agents whose actions modify / transform the social worlds in which they are inserted. The text of Professor Jens Qvortrup, responsible for the foundation of the first research group in sociology of childhood (RC53 at the International Sociological Association (ISA, and one of the organizers of the Handbook, focuses childhood as a social structure. Published as first chapter of The Palgrave Handbook of Childhood Studies, the study shows childhood as a segment in a social structure and the applications of a structural perspective, i.e. inserted in the theoretical studies of childhood, the chapter outlines an approach that differs from both research on socialization and

  7. Solid state characterization and crystal structure from X-ray powder diffraction of two polymorphic forms of ranitidine base.

    Science.gov (United States)

    de Armas, Héctor Novoa; Peeters, Oswald M; Blaton, Norbert; Van Gyseghem, Elke; Martens, Johan; Van Haele, Gerrit; Van Den Mooter, Guy

    2009-01-01

    Ranitidine hydrochloride (RAN-HCl), a known anti-ulcer drug, is the product of reaction between HCl and ranitidine base (RAN-B). RAN-HCl has been extensively studied; however this is not the case of the RAN-B. The solid state characterization of RAN-B polymorphs has been carried out using different analytical techniques (microscopy, thermal analysis, Fourier transform infrared spectrometry in the attenuated total reflection mode, (13)C-CPMAS-NMR spectroscopy and X-ray powder diffraction). The crystal structures of RAN-B form I and form II have been determined using conventional X-ray powder diffraction in combination with simulated annealing and whole profile pattern matching, and refined using rigid-body Rietveld refinement. RAN-B form I is a monoclinic polymorph with cell parameters: a = 7.317(2), b = 9.021(2), c = 25.098(6) A, beta = 95.690(1) degrees and space group P2(1)/c. The form II is orthorhombic: a = 31.252(4), b = 13.052(2), c = 8.0892(11) A with space group Pbca. In RAN-B polymorphs, the nitro group is involved in a strong intramolecular hydrogen bond responsible for the existence of a Z configuration in the enamine portion of the molecules. A tail to tail packing motif can be denoted via intermolecular hydrogen bonds. The crystal structures of RAN-B forms are compared to those of RAN-HCl polymorphs. RAN-B polymorphs are monotropic polymorphic pairs. (c) 2008 Wiley-Liss, Inc. and the American Pharmacists Association

  8. Seismic Failure Mechanism of Reinforced Cold-Formed Steel Shear Wall System Based on Structural Vulnerability Analysis

    Directory of Open Access Journals (Sweden)

    Jihong Ye

    2017-02-01

    Full Text Available A series of structural vulnerability analyses are conducted on a reinforced cold-formed steel (RCFS shear wall system and a traditional cold-formed steel (CFS shear wall system subjected to earthquake hazard based on forms in order to investigate their failure mechanisms. The RCFS shear wall adopts rigid beam-column joints and continuous concrete-filled CFS tube end studs rather than coupled-C section end studs that are used in traditional CFS shear walls, to achieve the rigid connections in both beam-column joints and column bases. The results show that: the RCFS and traditional CFS shear wall systems both exhibit the maximum vulnerability index associated with the failure mode in the first story. Therefore, the first story is likely to be a weakness of the CFS shear wall system. Once the wall is damaged, the traditional CFS shear wall system would collapse because the shear wall is the only lateral-resisting component. However, the collapse resistance of the RCFS shear wall system is effectively enhanced by the second defense, which is provided by a framework integrated by rigid beam-column joints and fixed column bases. The predicted collapse mode with maximum vulnerability index that was obtained by structural vulnerability analysis agrees well with the experimental result, and the structural vulnerability method is thereby verified to be reasonable to identify the weaknesses of framed structures and predict their collapse modes. Additionally, the quantitative vulnerability index indicates that the RCFS shear wall system exhibits better robustness compared to the traditional one. Furthermore, the “strong frame weak wallboard” and the “strong column weak beam” are proposed in this study as conceptional designations for the RCFS shear wall systems.

  9. Comparison of various molecular forms of bovine trypsin: Correlation of infrared spectra with X-ray crystal structures

    Energy Technology Data Exchange (ETDEWEB)

    Prestrelski, S.J. (Mount Sinai School of Medicine of the City Univ. of New York (USA)); Byler, D.M. (U.S. Department of Agriculture, Philadelphia, PA (USA)); Liebman, M.N. (AMOCO Technology Corporation, Naperville, IL (USA))

    1991-01-01

    Fourier-transform infrared spectroscopy is a valuable method for the study of protein conformation in solution primarily because of the sensitivity to conformation of the amide I band (1700-1620 cm{sup {minus}1}) which arises from the backbone C{double bond}O stretching vibration. Combined with resolution-enhancement techniques such as derivative spectroscopy and self-deconvolution, plus the application of iterative curve-fitting techniques, this method provides a wealth of information concerning protein secondary structure. Further extraction of conformational information from the amide I band is dependent upon discerning the correlations between specific conformation types and component bands in the amide I region. In this paper the authors report spectra-structure correlations derived from conformational perturbations in bovine trypsin which arise from autolytic processing, zymogen activation, and active-site inhibition. IR spectra were collected for the single-chain ({beta}-trypsin) and once-cleaved, double-chain ({alpha}-trypsin) forms as well as at various times during the course of autolysis and also for zymogen, trypsinogen, and {beta}-trypsin inhibited with diisopropyl fluorophosphate. Spectral differences among the various molecular forms were interpreted in light of previous biochemical studies of autolysis and the known three-dimensional structures of the zymogen, the active enzyme, and the DIP-inhibited form. The spectroscopic results from these proteins in D{sub 2}O imply that certain loop structures may absorb in the region of 1655 cm{sup {minus}1}. They estimate that this approach to data analysis and interpretation is sensitive to changes of 0.01 unit or less in the relative integrated intensities of component bands in spectra whose peaks are well resolved.

  10. Structural-energetic interpretation of competition between complex forms in the UBr3-MBr systems

    International Nuclear Information System (INIS)

    Suglobova, I.G.; Chirkst, D.Eh.

    1978-01-01

    The calorimetric method has been used for determining standard enthalpy values of the formation of bromouranates of alkali metals (M 2 UBr 5 ) and for checking the enthalpy value of the uranium tribromide formation. ΔH 0 of UBr 3 formation is -182.2+-0.5 kcal/mol. Enthalpies of the formation of pentabromouranates from binary bromides (and from simple substances) are: -6.6(-384.3) for K 2 VBr 5 , -9.7(-390.9) for Rb 2 VBr 5 , -10.21(-395.0) kcal/mol for Cs 2 VBr 5 . The error is +-0.5(+-10) kcal/mol. For Cs 3 VBr 6 the enthalpy of the formation is -10+-2 (-496+-3) kcal/mol. The M 2 VBr 5 compounds have rhombic lattices of the Tl 2 AlF 5 type. Sizes of elementary cells and uranium-alkali metal distances in polycrystals of the complexes have been determined on the base of X-ray diffraction patterns. Obtained picnometric densities of 4.51 (M=K), 4.79 (M=Rb), and 4.86+-0.01 g/cm 3 (M=Cs) agree with calculated values. The energy of the V(3)-Br bond is 53+-2 kcal/mol when the uranium coordination number equals 6. A new method has been proposed for evaluating the energy of the crystal lattice of the complexes by interionic distance with the aid of linear extrapolation of expeimental data for binary compounds in logarythmic coordinates. The relationship has been shown between the values and the nature of outer-spherical energetic effects and crystal structure of the complexes

  11. The structure environment, rock-magma system, mineral-forming series and pattern of volcanic mineral-forming of uranium deposit in southeast of China

    International Nuclear Information System (INIS)

    Yu Dagan

    1992-01-01

    The Volcanic uranium deposit of rock-magma belt-the Mid-Cz Volcano in the Southeast of China mainly formed around 120 ∼ 130 Ma and 90 ∼ 100 Ma Which is in harmony with the two rock magma activities of k within the region. The rock-magma system of this period formed around the turning period from pressure to tension in the continent margin of southeast China, which is mainly characterized by the appearance of A-type granite and alkaline, sub-alkaline rocks (trachyte, trachyandensite, trachybasalt, basic rock alkaline basalt). The uranium deposit is controlled by the base rift of dissection to the mantle, the volcanic basin is of the double characteristics of transversal rift valley basin (early period) ad tension rift valley basin (laster period). The leading role of the deep source is stressed in terms of internal-forming series of volcanic uranium deposits is considered to exist; and also in terms of internal-forming series of volcanic uranium deposits is considered to exist; and also in terms of mineral-forming patterns, the multi-pattern led by the deep-source is stressed, including the mineral-forming pattern of uranium deposit of continental thermos, repeated periphery mineral-forming pattern of uranium deposit and the mineral-forming pattern of uranium deposit of rising pole-like thermos. Ten suggestions are put forward to the next mineral-search according to the above thoughts

  12. The Structures of Coiled-Coil Domains from Type III Secretion System Translocators Reveal Homology to Pore-Forming Toxins

    Energy Technology Data Exchange (ETDEWEB)

    Barta, Michael L.; Dickenson, Nicholas E.; Patil, Mrinalini; Keightley, Andrew; Wyckoff, Gerald J.; Picking, William D.; Picking, Wendy L.; Geisbrecht, Brian V. (UMKC); (OKLU)

    2012-03-26

    Many pathogenic Gram-negative bacteria utilize type III secretion systems (T3SSs) to alter the normal functions of target cells. Shigella flexneri uses its T3SS to invade human intestinal cells to cause bacillary dysentery (shigellosis) that is responsible for over one million deaths per year. The Shigella type III secretion apparatus is composed of a basal body spanning both bacterial membranes and an exposed oligomeric needle. Host altering effectors are secreted through this energized unidirectional conduit to promote bacterial invasion. The active needle tip complex of S. flexneri is composed of a tip protein, IpaD, and two pore-forming translocators, IpaB and IpaC. While the atomic structure of IpaD has been elucidated and studied, structural data on the hydrophobic translocators from the T3SS family remain elusive. We present here the crystal structures of a protease-stable fragment identified within the N-terminal regions of IpaB from S. flexneri and SipB from Salmonella enterica serovar Typhimurium determined at 2.1 {angstrom} and 2.8 {angstrom} limiting resolution, respectively. These newly identified domains are composed of extended-length (114 {angstrom} in IpaB and 71 {angstrom} in SipB) coiled-coil motifs that display a high degree of structural homology to one another despite the fact that they share only 21% sequence identity. Further structural comparisons also reveal substantial similarity to the coiled-coil regions of pore-forming proteins from other Gram-negative pathogens, notably, colicin Ia. This suggests that these mechanistically separate and functionally distinct membrane-targeting proteins may have diverged from a common ancestor during the course of pathogen-specific evolutionary events.

  13. Mapping local structural perturbations in the native state of stefin B (cystatin B under amyloid forming conditions

    Directory of Open Access Journals (Sweden)

    Robert eParamore

    2012-10-01

    Full Text Available Unlike a number of amyloid-forming proteins, stefins, in particular stefin B (cystatin B form amyloids under conditions where the native state predominates. In order to trigger oligomerization processes, the stability of the protein needs to be compromised, favoring structural re-arrangement however, accelerating fibril formation is not a simple function of protein stability. We report here on how optimal conditions for amyloid formation lead to the destabilization of dimeric and tetrameric states of the protein in favor of the monomer. Small, highly localized structural changes can be mapped out that allow us to visualize directly areas of the protein which eventually become responsible for triggering amyloid formation. These regions of the protein overlap with the Cu (II-binding sites which we identify here for the first time. We hypothesize that in vivo modulators of amyloid formation may act similarly to painstakingly optimized solvent conditions developed in vitro. We discuss these data in the light of current structural models of stefin B amyloid fibrils based on H-exchange data, where the detachment of the helical part and the extension of loops were observed.

  14. Energy band structure and electrical properties of Ga-oxide/GaN interface formed by remote oxygen plasma

    Science.gov (United States)

    Yamamoto, Taishi; Taoka, Noriyuki; Ohta, Akio; Truyen, Nguyen Xuan; Yamada, Hisashi; Takahashi, Tokio; Ikeda, Mitsuhisa; Makihara, Katsunori; Nakatsuka, Osamu; Shimizu, Mitsuaki; Miyazaki, Seiichi

    2018-06-01

    The energy band structure of a Ga-oxide/GaN structure formed by remote oxygen plasma exposure and the electrical interface properties of the GaN metal–oxide–semiconductor (MOS) capacitors with the SiO2/Ga-oxide/GaN structures with postdeposition annealing (PDA) at various temperatures have been investigated. Reflection high-energy electron diffraction and X-ray photoelectron spectroscopy clarified that the formed Ga-oxide layer is neither a single nor polycrystalline phase with high crystallinity. We found that the energy band offsets at the conduction band minimum and at the valence band maximum between the Ga-oxide layer and the GaN surface were 0.4 and 1.2 ± 0.2 eV, respectively. Furthermore, capacitance–voltage (C–V) characteristics revealed that the interface trap density (D it) is lower than the evaluation limit of Terman method without depending on the PDA temperatures, and that the SiO2/Ga-oxide stack can work as a protection layer to maintain the low D it, avoiding the significant decomposition of GaN at the high PDA temperature of 800 °C.

  15. Composition, structure and morphology of oxide layers formed on austenitic stainless steel by oxygen plasma immersion ion implantation

    International Nuclear Information System (INIS)

    Anandan, C.; Rajam, K.S.

    2007-01-01

    Oxygen ions were implanted in to austenitic stainless steel by plasma immersion ion implantation at 400 deg. C. The implanted samples were characterized by XPS, GIXRD, micro-Raman, AFM, optical and scanning electron microscopies. XPS studies showed the presence of Fe in elemental, as Fe 2+ in oxide form and as Fe 3+ in the form of oxyhydroxides in the substrate. Iron was present in the oxidation states of Fe 2+ and Fe 3+ in the implanted samples. Cr and Mn were present as Cr 3+ and Mn 2+ , respectively, in both the substrate and implanted samples. Nickel remained unaffected by implantation. GIXRD and micro-Raman studies showed the oxide to be a mixture of spinel and corundum structures. Optical and AFM images showed an island structure on underlying oxide. This island structure was preserved at different thicknesses. Further, near the grain boundaries more oxide growth was found. This is explained on the basis of faster diffusion of oxygen in the grain boundary regions. Measurement of total hemispherical optical aborptance, α and emittance, ε of the implanted sample show that it has good solar selective properties

  16. Thermal Analysis by Structural Characterization as a Method for Assessing Heterogeneity in Complex Solid Pharmaceutical Dosage Forms.

    Science.gov (United States)

    Alhijjaj, Muqdad; Reading, Mike; Belton, Peter; Qi, Sheng

    2015-11-03

    Characterizing inter- and intrasample heterogeneity of solid and semisolid pharmaceutical products is important both for rational design of dosage forms and subsequent quality control during manufacture; however, most pharmaceutical products are multicomponent formulations that are challenging in this regard. Thermal analysis, in particular differential scanning calorimetry, is commonly used to obtain structural information, such as degree of crystallinity, or identify the presence of a particular polymorph, but the results are an average over the whole sample; it cannot directly provide information about the spatial distribution of phases. This study demonstrates the use of a new thermo-optical technique, thermal analysis by structural characterization (TASC), that can provide spatially resolved information on thermal transitions by applying a novel algorithm to images acquired by hot stage microscopy. We determined that TASC can be a low cost, relatively rapid method of characterizing heterogeneity and other aspects of structure. In the examples studied, it was found that high heating rates enabled screening times of 3-5 min per sample. In addition, this study demonstrated the higher sensitivity of TASC for detecting the metastable form of polyethylene glycol (PEG) compared to conventional differential scanning calorimetry (DSC). This preliminary work suggests that TASC will be a worthwhile additional tool for characterizing a broad range of materials.

  17. Single-Point Incremental Forming of Two Biocompatible Polymers: An Insight into Their Thermal and Structural Properties

    Directory of Open Access Journals (Sweden)

    Luis Marcelo Lozano-Sánchez

    2018-04-01

    Full Text Available Sheets of polycaprolactone (PCL and ultra-high molecular weight polyethylene (UHMWPE were fabricated and shaped by the Single-Point Incremental Forming process (SPIF. The performance of these biocompatible polymers in SPIF was assessed through the variation of four main parameters: the diameter of the forming tool, the spindle speed, the feed rate, and the step size based on a Box–Behnken design of experiments of four variables and three levels. The design of experiments allowed us to identify the parameters that most affect the forming of PCL and UHMWPE. The study was completed by means of a deep characterization of the thermal and structural properties of both polymers. These properties were correlated to the performance of the polymers observed in SPIF, and it was found that the polymer chains are oriented as a consequence of the SPIF processing. Moreover, by X-ray diffraction it was proved that polymer chains behave differently on each surface of the fabricated parts, since the chains on the surface in contact with the forming tool are oriented horizontally, while on the opposite surface they are oriented in the vertical direction. The unit cell of UHMWPE is distorted, passing from an orthorhombic cell to a monoclinic due to the slippage between crystallites. This slippage between crystallites was observed in both PCL and UHMWPE, and was identified as an alpha star thermal transition located in the rubbery region between the glass transition and the melting point of each polymer.

  18. Morphological, structural and optical properties of ZnO thin solid films formed by nanoleafs or micron/submicron cauliflowers

    International Nuclear Information System (INIS)

    Angulo-Rocha, Jorge; Velarde-Escobar, Oscar; Yee-Rendón, Cristo; Atondo-Rubio, Gelacio; Millan-Almaraz, Roberto; Camarillo-García, Enrique

    2017-01-01

    Thin films of ZnO formed by nano and microstructures with hexagonal crystal phase were successfully synthesized by using pyrolysis technique. At first glance the films resulted divided in 7 zones that were morphologically analyzed and showed the presence of three types of particles: nano-leafs, single microparticles, and particles formed by the addition of microparticles, “clusters”. The largest and therefore the main zone was formed by nanoleafs. Studies on morphology, structure and optical properties of these nanoleafs were obtained and correlated too. The knowledge acquired from these studies allowed the synthesis of nanostructured films entirely formed by nanoleafs with a width of 25 nm and a length 200 nm long regardless of the roughness of the substrate. Energy gap of 3.26 eV was invariant to changes in synthesis parameters. The studies on optical properties of nanoleafs and micro-cauliflower give an energy diagram that account for the location of the energy states introduced by native crystalline defects into the energy band gap and their radiative electronic transitions.

  19. Morphological, structural and optical properties of ZnO thin solid films formed by nanoleafs or micron/submicron cauliflowers

    Energy Technology Data Exchange (ETDEWEB)

    Angulo-Rocha, Jorge [Laboratorio de Síntesis de Materiales-Facultad de Ciencias Físico-Matemáticas – Universidad Autónoma de Sinaloa, Ciudad Universitaria S/N, CP. 80000, Culiacán, Sinaloa, México (Mexico); Velarde-Escobar, Oscar; Yee-Rendón, Cristo; Atondo-Rubio, Gelacio [Laboratorio de Óptica-Facultad de Ciencias Físico-Matemáticas – Universidad Autónoma de Sinaloa, Ciudad Universitaria S/N, CP. 80000, Culiacán, Sinaloa, México (Mexico); Millan-Almaraz, Roberto [Facultad de Ciencias Físico-Matemáticas – Universidad Autónoma de Sinaloa, Ciudad Universitaria S/N, CP. 80000, Culiacán, Sinaloa, México (Mexico); Camarillo-García, Enrique [Instituto de Física, Universidad Nacional Autónoma de México, AP 20-364, Álvaro Obregón 01000, DF, México (Mexico); and others

    2017-05-15

    Thin films of ZnO formed by nano and microstructures with hexagonal crystal phase were successfully synthesized by using pyrolysis technique. At first glance the films resulted divided in 7 zones that were morphologically analyzed and showed the presence of three types of particles: nano-leafs, single microparticles, and particles formed by the addition of microparticles, “clusters”. The largest and therefore the main zone was formed by nanoleafs. Studies on morphology, structure and optical properties of these nanoleafs were obtained and correlated too. The knowledge acquired from these studies allowed the synthesis of nanostructured films entirely formed by nanoleafs with a width of 25 nm and a length 200 nm long regardless of the roughness of the substrate. Energy gap of 3.26 eV was invariant to changes in synthesis parameters. The studies on optical properties of nanoleafs and micro-cauliflower give an energy diagram that account for the location of the energy states introduced by native crystalline defects into the energy band gap and their radiative electronic transitions.

  20. Structure of 1,5-Anhydro-D-Fructose: X-ray Analysis of Crystalline Acetylated Dimeric Forms

    DEFF Research Database (Denmark)

    Lundt, Inge; Andersen, Søren Møller; Marcussen, Jan

    1998-01-01

    Acetylation of 1,5-anhydro-D-fructose under acidic conditions gave two crystalline acetylated dimeric forms, which by X-ray analysis were shown to be diastereomeric spiroketals formed between C-2 and C-2´/C-3´. The structures of the compounds differed only at the configuration at C-2. Acetylation...... or benzoylation of 1,5-anhydro-D-fructose in pyridine yielded 3,6-di-O-acetyl-1,5-anhydro-4-deoxy-D-glycero-hex-3-enos-2-ulopyra -nose or crystalline 1,5-anhydro-3,6-di-O-benzoyl-4-deoxy-D-glycero-hex-3-enos-2-ulo-py ranose....

  1. High-resolution structure of AKR1a4 in the apo form and its interaction with ligands

    International Nuclear Information System (INIS)

    Faucher, Frédérick; Jia, Zongchao

    2012-01-01

    Despite its high affinity for NADPH, AKR1a4 crystallized in the apo form, which is very rare for aldo-keto reductase enzymes. Aldo-keto reductase 1a4 (AKR1a4; EC 1.1.1.2) is the mouse orthologue of human aldehyde reductase (AKR1a1), the founding member of the AKR family. As an NADPH-dependent enzyme, AKR1a4 catalyses the conversion of d-glucuronate to l-gulonate. AKR1a4 is involved in ascorbate biosynthesis in mice, but has also recently been found to interact with SMAR1, providing a novel mechanism of ROS regulation by ATM. Here, the crystal structure of AKR1a4 in its apo form at 1.64 Å resolution as well as the characterization of the binding of AKR1a4 to NADPH and P44, a peptide derived from SMAR1, is presented

  2. Canopy-forming seaweeds in urchin-dominated systems in eastern Canada: structuring forces or simple prey for keystone grazers?

    Directory of Open Access Journals (Sweden)

    Caitlin Blain

    Full Text Available Models of benthic community dynamics for the extensively studied, shallow rocky ecosystems in eastern Canada emphasize kelp-urchin interactions. These models may bias the perception of factors and processes that structure communities, for they largely overlook the possible contribution of other seaweeds to ecosystem resilience. We examined the persistence of the annual, acidic (H2SO4, brown seaweed Desmarestia viridis in urchin barrens at two sites in Newfoundland (Canada throughout an entire growth season (February to October. We also compared changes in epifaunal assemblages in D. viridis and other conspicuous canopy-forming seaweeds, the non-acidic conspecific Desmarestia aculeata and kelp Agarum clathratum. We show that D. viridis can form large canopies within the 2-to-8 m depth range that represent a transient community state termed "Desmarestia bed". The annual resurgence of Desmarestia beds and continuous occurrence of D. aculeata and A. clathratum, create biological structure for major recruitment pulses in invertebrate and fish assemblages (e.g. from quasi-absent gastropods to >150,000 recruits kg(-1 D. viridis. Many of these pulses phase with temperature-driven mass release of acid to the environment and die-off in D. viridis. We demonstrate experimentally that the chemical makeup of D. viridis and A. clathratum helps retard urchin grazing compared to D. aculeata and the highly consumed kelp Alaria esculenta. In light of our findings and related studies, we propose fundamental changes to the study of community shifts in shallow, rocky ecosystems in eastern Canada. In particular, we advocate the need to regard certain canopy-forming seaweeds as structuring forces interfering with top-down processes, rather than simple prey for keystone grazers. We also propose a novel, empirical model of ecological interactions for D. viridis. Overall, our study underscores the importance of studying organisms together with cross-scale environmental

  3. [Forming of the visual cognitive structures in the monkey conditioned-reflex behaviour: the dependence on the sensory information].

    Science.gov (United States)

    Dudkin, K N; Chueva, I V

    2008-01-01

    In monkeys, changes in size and shape of figures led to a significant decrease of correct solutions in training and a considerable increase of refusals from solution of tasks as well as the time of their motor response. The invariance of differentiation in this case was achieved after additional training. The data obtained show that, based on the stimulus sensory processing in conditioned-reflex training, in the long-term memory some differentiating signs are formed: the cognitive structures (the functional neurophysiological mechanisms) maintaining the classification of visual images. With these structures, temporary conditioned connection will be established. Their formation will be determined by the type of sensory information and provided for by existence in the long-term memory of separate subsystems for spatial as well as non-spatial information.

  4. 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

  5. Effect of Extracted Compositions of Liquefaction Residue on the Structure and Properties of the Formed-coke

    Directory of Open Access Journals (Sweden)

    Song Yong-hui

    2016-01-01

    Full Text Available The purpose of this paper is to study the effect of extracted compositions of the de-ash liquefaction residue (D-DCLR on pyrolysis products yields, compressive strength and composition of the formed-coke, which was prepared by co-pyrolysis of the low metamorphic pulverized coal and D-DCLR. The scanning electron microscope (SEM and the Fourier Transform Infrared (FT-IR were used to characterize the morphology and functional group of the formed-coke, respectively. The results showed that the extracted compositions of D-DCLR were heavy oil (HS, asphaltene (A, pre-asphaltene (PA and tetrahydrofuran isolusion (THFIS, whose contents were 5.10%, 40.90%, 14.4%, 39.60%, respectively. During the pyrolysis process, HS was the main source of tar, and HS, A as well as PA were conducive to improve gas yields. The THFIS helped to improve the yield of the formed-coke up to 89.5%, corresponding to the compressive strength was only 147.7N/ball for the coke. A and PA were the key factors affecting the compressive strength and surface structure of the formed-coke. The compressive strength of coke could be up to 728.0N/ball with adding D-DCLR, which reduced by 50% after the removal of A and PA. The FT-IR analysis showed that the types of surface functional groups of the formed-coke were remained the same after co-pyrolysis, but the absorption peak intensity of each functional group was changed.

  6. Electronic structure of SnF{sub 3}: An example of valence skipper which forms charge density wave

    Energy Technology Data Exchange (ETDEWEB)

    Hase, I., E-mail: i.hase@aist.go.jp [National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8568 (Japan); Yanagisawa, T. [National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8568 (Japan); Kawashima, K. [IMRA Material R& D Co., LTD., Kariya, Aichi 448-0032 (Japan)

    2016-11-15

    Highlights: • We calculated the electronic structure of SnF{sub 3} and BaBiO{sub 3} from first principles. • As for SnF{sub 3}, charge-density-wave (CDW) is found, which agrees with the experiment. • As for BaBiO{sub 3}, CDW is not found, contrary to the experiment. • We conclude that the CDW is hard in SnF{sub 3} and is soft in BaBiO{sub 3}. - Abstract: In the present study we calculated the electronic structure of the valence skipping compound SnF{sub 3} and BaBiO{sub 3} from first-principles. We confirmed that the charge-density-wave (CDW) is formed in SnF{sub 3}, and the Sn atoms in two crystallographic different sites take the valence Sn{sup 2+} and Sn{sup 4+}. Structure optimization study reveals that this CDW is stable, though the atomic position is slightly different from the experimental data. This behavior is in contrast with the case of BaBiO{sub 3}, where the structure optimization leads to the uniform state, which means that two Bi sites are equivalent. The CDW state is hard in SnF{sub 3}, which means that the CDW gap is large enough and it is difficult to melt this CDW order.

  7. The quadratic-form identity for constructing Hamiltonian structures of the NLS-MKdV hierarchy and multi-component Levi hierarchy

    International Nuclear Information System (INIS)

    Dong Huanhe; Wang Xiangrong

    2008-01-01

    The trace identity is extended to the quadratic-form identity. The Hamiltonian structures of the NLS-MKdV hierarchy, and integrable coupling of multi-component Levi hierarchy are obtained by the quadratic-form identity. The method can be used to produce the Hamiltonian structures of the other integrable couplings or multi-component hierarchies

  8. Valles Marineris as a Cryokarstic Structure Formed by a Giant Dyke System: Support From New Analogue Experiments

    Science.gov (United States)

    Ozeren, M. S.; Sengor, A. M. C.; Acar, D.; Ülgen, S. C.; Onsel, I. E.

    2014-12-01

    Valles Marineris is the most significant near-linear depression on Mars. It is some 4000 km long, up to about 200 km wide and some 7 km deep. Although its margins look parallel at first sight, the entire structure has a long spindle shape with significant enlargement in its middle (Melas Chasma) caused by cuspate slope retreat mechanisms. Farther to its north is Hebes Chasma which is an entirely closed depression with a more pronounced spindle shape. Tithonium Chasma is a parallel, but much narrower depression to its northeast. All these chasmae have axes parallel with one another and such structures occur nowhere else on Mars. A scabland surface exists to the east of the Valles Marineris and the causative water mass seems to have issued from it. The great resemblance of these chasmae on mars to poljes in the karstic regions on earth have led us to assume that they owed their existence to dissolution of rock layers underlying them. We assumed that the dissolving layer consisted of water ice forming substantial layers, in fact entirely frozen seas of several km depth. We have simulated this geometry by using bentonite and flour layers (in different experiments) overlying layers of ice in which a resistant coil was used to simulate a dyke. We used different thicknesses of bentonite and flour overlying ice layers again of various thicknesses. The flour seems to simulate the Martian crust better because on Mars, g is only about 3/8ths of its value on Earth, so (for equal crustal density) the depth to which the cohesion term C remains important in the Mohr-Coulomb shear failure criterion is about 8/3 times greater. As examples we show two of those experiments in which both the rock analogue and ice layers were of 1.5 cm. thick. Perfect analogues of the Valles Marineris formed above the dyke analogue thermal source complete with the near-linear structure, overall flat spindle shape, cuspate margins, a central ridge, parallel side faults, parallel depressions resembling

  9. Determination of the Structure of Vitrified Hydroceramic/CBC Waste Form Glasses Manufactured from DOE Reprocessing Waste

    International Nuclear Information System (INIS)

    Scheetz, B.E.; White, W. B.; Chesleigh, M.; Portanova, A.; Olanrewaju, J.

    2005-01-01

    industry with decades of practical experience. The research undertaken in the present investigation builds on a previous study under the NEER program. The earlier studies identified an optimal formulation for the immobilization of the calcine that is both compositionally adequate to retain radionuclides as well as hazardous constituents and which has a reaction rate that will allow the technical employment of the process. The study established in a general way the glass-forming region in the system M 2 O-MO-Al 2 O 3 -SiO 2 (M 2 0 = alkali metal oxides; MO = alkaline earth metal oxide) which provides the base for these hydroceramic/CBC materials (Fig. 1). The objectives of the present program are to track the structural changes that take place during formulation, chemical reaction, and HIPing. Compositions must be varied through the glass-forming region, structures of the crystals and glass matrix of the glass-ceramic determined, and the structural characteristics in turn related to stability and leachability of the final products

  10. Chemical and structural analyses of subsurface crevices formed during spontaneous deposition of cerium-based conversion coatings

    Energy Technology Data Exchange (ETDEWEB)

    Heller, Daimon K, E-mail: dkheller@mmm.com; Fahrenholtz, William G., E-mail: billf@mst.edu; O' Keefe, Matthew J., E-mail: mjokeefe@mst.edu

    2011-11-15

    Subsurface crevices formed during the deposition of cerium-based conversion coatings were analyzed in cross-section to assess the effect of deposition and post-treatment on the structure and chemistry of phases present. An Al-O containing phase, believed to be amorphous Al(OH){sub 3}, was formed in crevices during coating deposition. Analysis by energy dispersive X-ray spectroscopy revealed the presence of up to 1.6 at.% chlorine within the Al-O phase, which was likely a product of soluble chlorides that were present in the coating solution. Cerium was not detected within crevices. After post-treatment in an 85 deg. C aqueous phosphate solution, the chloride concentration was reduced to {<=} 0.30 at.% and electron diffraction of the Al-O phase produced ring patterns, indicating it had crystallized. Some diffraction patterns could be indexed to gibbsite (Al(OH){sub 3}), but others are believed to be a combination of hydrated aluminum hydroxides and/or oxides. Aluminum phosphate was not identified. Separately from its effect on cerium-based conversion coatings, phosphate post-treatment improved the corrosion resistance of Al 2024-T3 substrates by acting to crystallize Al(OH){sub 3} present on interior surfaces of crevices and by reducing the chloride concentration in this phase. - Highlights: {yields} Analysis of subsurface crevices formed during deposition of Ce-based conversion coatings. {yields} Phosphate post-treatment improved corrosion protection in salt spray testing. {yields} Post-treatment affected the composition and structure of regions within crevices. {yields} Crystallized Al(OH){sub 3} within crevices acted as a more effective barrier to chloride ions.

  11. Role of string-like collective atomic motion on diffusion and structural relaxation in glass forming Cu-Zr alloys

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Hao [International Center for New-Structured Materials (ICNSM), Zhejiang University and Laboratory of New-Structured Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 2V4 (Canada); Zhong, Cheng; Wang, Xiaodong; Cao, Qingping; Jiang, Jian-Zhong, E-mail: jiangjz@zju.edu.cn, E-mail: jack.douglas@nist.gov [International Center for New-Structured Materials (ICNSM), Zhejiang University and Laboratory of New-Structured Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou 310027 (China); Douglas, Jack F., E-mail: jiangjz@zju.edu.cn, E-mail: jack.douglas@nist.gov [Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Zhang, Dongxian [State Key Laboratory of Modern Optical Instrumentation, Zhejiang University, Hangzhou 310027 (China)

    2015-04-28

    We investigate Cu-Zr liquid alloys using molecular dynamics simulation and well-accepted embedded atom method potentials over a wide range of chemical composition and temperature as model metallic glass-forming (GF) liquids. As with other types of GF materials, the dynamics of these complex liquids are characterized by “dynamic heterogeneity” in the form of transient polymeric clusters of highly mobile atoms that are composed in turn of atomic clusters exhibiting string-like cooperative motion. In accordance with the string model of relaxation, an extension of the Adam-Gibbs (AG) model, changes in the activation free energy ΔG{sub a} with temperature of both the Cu and Zr diffusion coefficients D, and the alpha structural relaxation time τ{sub α} can be described to a good approximation by changes in the average string length, L. In particular, we confirm that the strings are a concrete realization of the abstract “cooperatively rearranging regions” of AG. We also find coexisting clusters of relatively “immobile” atoms that exhibit predominantly icosahedral local packing rather than the low symmetry packing of “mobile” atoms. These two distinct types of dynamic heterogeneity are then associated with different fluid structural states. Glass-forming liquids are thus analogous to polycrystalline materials where the icosahedrally packed regions correspond to crystal grains, and the strings reside in the relatively disordered grain boundary-like regions exterior to these locally well-ordered regions. A dynamic equilibrium between localized (“immobile”) and wandering (“mobile”) particles exists in the liquid so that the dynamic heterogeneity can be considered to be type of self-assembly process. We also characterize changes in the local atomic free volume in the course of string-like atomic motion to better understand the initiation and propagation of these fluid excitations.

  12. Femtometer toroidal structures in nuclei

    International Nuclear Information System (INIS)

    Forest, J.L.; Pandharipande, V.R.; Pieper, S.C.; Wiringa, R.B.; Schiavilla, R.; Arriaga, A.

    1996-01-01

    The two-nucleon density distributions in states with isospin T=0, spin S=1, and projection M S =0 and ±1 are studied in 2 H, 3,4 He, 6,7 Li, and 16 O. The equidensity surfaces for M S =0 distributions are found to be toroidal in shape, while those of M S =±1 have dumbbell shapes at large density. The dumbbell shapes are generated by rotating tori. The toroidal shapes indicate that the tensor correlations have near maximal strength at r 3 He, 4 He, and 6 Li. The toroidal distribution has a maximum-density diameter of ∼1 fm and a half-maximum density thickness of ∼0.9 fm. Many realistic models of nuclear forces predict these values, which are supported by the observed electromagnetic form factors of the deuteron, and also predicted by classical Skyrme effective Lagrangians, related to QCD in the limit of infinite colors. Due to the rather small size of this structure, it could have a revealing relation to certain aspects of QCD. Experiments to probe this structure and its effects in nuclei are suggested. Pair distribution functions in other T,S channels are also discussed; those in T,S=1,1 have anisotropies expected from one-pion-exchange interactions. The tensor correlations in T,S=0,1 states are found to deplete the number of T,S=1,0 pairs in nuclei and cause a reduction in nuclear binding energies via many-body effects. copyright 1996 The American Physical Society

  13. TDP-43 inclusion bodies formed in bacteria are structurally amorphous, non-amyloid and inherently toxic to neuroblastoma cells.

    Directory of Open Access Journals (Sweden)

    Claudia Capitini

    Full Text Available Accumulation of ubiquitin-positive, tau- and α-synuclein-negative intracellular inclusions of TDP-43 in the central nervous system represents the major hallmark correlated to amyotrophic lateral sclerosis and frontotemporal lobar degeneration with ubiquitin-positive inclusions. Such inclusions have variably been described as amorphous aggregates or more structured deposits having an amyloid structure. Following the observations that bacterial inclusion bodies generally consist of amyloid aggregates, we have overexpressed full-length TDP-43 and C-terminal TDP-43 in E. coli, purified the resulting full-length and C-terminal TDP-43 containing inclusion bodies (FL and Ct TDP-43 IBs and subjected them to biophysical analyses to assess their structure/morphology. We show that both FL and Ct TDP-43 aggregates contained in the bacterial IBs do not bind amyloid dyes such as thioflavin T and Congo red, possess a disordered secondary structure, as inferred using circular dichroism and infrared spectroscopies, and are susceptible to proteinase K digestion, thus possessing none of the hallmarks for amyloid. Moreover, atomic force microscopy revealed an irregular structure for both types of TDP-43 IBs and confirmed the absence of amyloid-like species after proteinase K treatment. Cell biology experiments showed that FL TDP-43 IBs were able to impair the viability of cultured neuroblastoma cells when added to their extracellular medium and, more markedly, when transfected into their cytosol, where they are at least in part ubiquitinated and phosphorylated. These data reveal an inherently high propensity of TDP-43 to form amorphous aggregates, which possess, however, an inherently high ability to cause cell dysfunction. This indicates that a gain of toxic function caused by TDP-43 deposits is effective in TDP-43 pathologies, in addition to possible loss of function mechanisms originating from the cellular mistrafficking of the protein.

  14. Crystal structure of the fluorescent protein from Dendronephthya sp. in both green and photoconverted red forms

    Energy Technology Data Exchange (ETDEWEB)

    Pletneva, Nadya V.; Pletnev, Sergei; Pakhomov, Alexey A.; Chertkova, Rita V.; Martynov, Vladimir I.; Muslinkina, Liya; Dauter, Zbigniew; Pletnev, Vladimir Z.

    2016-07-13

    The fluorescent protein fromDendronephthyasp. (DendFP) is a member of the Kaede-like group of photoconvertible fluorescent proteins with a His62-Tyr63-Gly64 chromophore-forming sequence. Upon irradiation with UV and blue light, the fluorescence of DendFP irreversibly changes from green (506 nm) to red (578 nm). The photoconversion is accompanied by cleavage of the peptide backbone at the Cα—N bond of His62 and the formation of a terminal carboxamide group at the preceding Leu61. The resulting double Cα=Cβbond in His62 extends the conjugation of the chromophore π system to include imidazole, providing the red fluorescence. Here, the three-dimensional structures of native green and photoconverted red forms of DendFP determined at 1.81 and 2.14 Å resolution, respectively, are reported. This is the first structure of photoconverted red DendFP to be reported to date. The structure-based mutagenesis of DendFP revealed an important role of positions 142 and 193: replacement of the original Ser142 and His193 caused a moderate red shift in the fluorescence and a considerable increase in the photoconversion rate. It was demonstrated that hydrogen bonding of the chromophore to the Gln116 and Ser105 cluster is crucial for variation of the photoconversion rate. The single replacement Gln116Asn disrupts the hydrogen bonding of Gln116 to the chromophore, resulting in a 30-fold decrease in the photoconversion rate, which was partially restored by a further Ser105Asn replacement.

  15. A 3D model of the membrane protein complex formed by the white spot syndrome virus structural proteins.

    Directory of Open Access Journals (Sweden)

    Yun-Shiang Chang

    Full Text Available BACKGROUND: Outbreaks of white spot disease have had a large negative economic impact on cultured shrimp worldwide. However, the pathogenesis of the causative virus, WSSV (whit spot syndrome virus, is not yet well understood. WSSV is a large enveloped virus. The WSSV virion has three structural layers surrounding its core DNA: an outer envelope, a tegument and a nucleocapsid. In this study, we investigated the protein-protein interactions of the major WSSV structural proteins, including several envelope and tegument proteins that are known to be involved in the infection process. PRINCIPAL FINDINGS: In the present report, we used coimmunoprecipitation and yeast two-hybrid assays to elucidate and/or confirm all the interactions that occur among the WSSV structural (envelope and tegument proteins VP51A, VP19, VP24, VP26 and VP28. We found that VP51A interacted directly not only with VP26 but also with VP19 and VP24. VP51A, VP19 and VP24 were also shown to have an affinity for self-interaction. Chemical cross-linking assays showed that these three self-interacting proteins could occur as dimers. CONCLUSIONS: From our present results in conjunction with other previously established interactions we construct a 3D model in which VP24 acts as a core protein that directly associates with VP26, VP28, VP38A, VP51A and WSV010 to form a membrane-associated protein complex. VP19 and VP37 are attached to this complex via association with VP51A and VP28, respectively. Through the VP26-VP51C interaction this envelope complex is anchored to the nucleocapsid, which is made of layers of rings formed by VP664. A 3D model of the nucleocapsid and the surrounding outer membrane is presented.

  16. 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.

  17. Factor structure and item level psychometrics of the Social Problem Solving Inventory-Revised: Short Form in traumatic brain injury.

    Science.gov (United States)

    Li, Chih-Ying; Waid-Ebbs, Julia; Velozo, Craig A; Heaton, Shelley C

    2016-01-01

    Social problem-solving deficits characterise individuals with traumatic brain injury (TBI), and poor social problem solving interferes with daily functioning and productive lifestyles. Therefore, it is of vital importance to use the appropriate instrument to identify deficits in social problem solving for individuals with TBI. This study investigates factor structure and item-level psychometrics of the Social Problem Solving Inventory-Revised: Short Form (SPSI-R:S), for adults with moderate and severe TBI. Secondary analysis of 90 adults with moderate and severe TBI who completed the SPSI-R:S was performed. An exploratory factor analysis (EFA), principal components analysis (PCA) and Rasch analysis examined the factor structure and item-level psychometrics of the SPSI-R:S. The EFA showed three dominant factors, with positively worded items represented as the most definite factor. The other two factors are negative problem-solving orientation and skills; and negative problem-solving emotion. Rasch analyses confirmed the three factors are each unidimensional constructs. It was concluded that the total score interpretability of the SPSI-R:S may be challenging due to the multidimensional structure of the total measure. Instead, we propose using three separate SPSI-R:S subscores to measure social problem solving for the TBI population.

  18. Factor Structure and Item Level Psychometrics of the Social Problem Solving Inventory Revised-Short Form in Traumatic Brain Injury

    Science.gov (United States)

    Li, Chih-Ying; Waid-Ebbs, Julia; Velozo, Craig A.; Heaton, Shelley C.

    2016-01-01

    Primary Objective Social problem solving deficits characterize individuals with traumatic brain injury (TBI). Poor social problem solving interferes with daily functioning and productive lifestyles. Therefore, it is of vital importance to use the appropriate instrument to identify deficits in social problem solving for individuals with TBI. This study investigates factor structure and item-level psychometrics of the Social Problem Solving Inventory-Revised Short Form (SPSI-R:S), for adults with moderate and severe TBI. Research Design Secondary analysis of 90 adults with moderate and severe TBI who completed the SPSI-R:S. Methods and Procedures An exploratory factor analysis (EFA), principal components analysis (PCA) and Rasch analysis examined the factor structure and item-level psychometrics of the SPSI-R:S. Main Outcomes and Results The EFA showed three dominant factors, with positively worded items represented as the most definite factor. The other two factors are negative problem solving orientation and skills; and negative problem solving emotion. Rasch analyses confirmed the three factors are each unidimensional constructs. Conclusions The total score interpretability of the SPSI-R:S may be challenging due to the multidimensional structure of the total measure. Instead, we propose using three separate SPSI-R:S subscores to measure social problem solving for the TBI population. PMID:26052731

  19. Deforming black hole and cosmological solutions by quasiperiodic and/or pattern forming structures in modified and Einstein gravity

    Science.gov (United States)

    Bubuianu, Laurenţiu; Vacaru, Sergiu I.

    2018-05-01

    We elaborate on the anholonomic frame deformation method, AFDM, for constructing exact solutions with quasiperiodic structure in modified gravity theories, MGTs, and general relativity, GR. Such solutions are described by generic off-diagonal metrics, nonlinear and linear connections and (effective) matter sources with coefficients depending on all spacetime coordinates via corresponding classes of generation and integration functions and (effective) matter sources. There are studied effective free energy functionals and nonlinear evolution equations for generating off-diagonal quasiperiodic deformations of black hole and/or homogeneous cosmological metrics. The physical data for such functionals are stated by different values of constants and prescribed symmetries for defining quasiperiodic structures at cosmological scales, or astrophysical objects in nontrivial gravitational backgrounds some similar forms as in condensed matter physics. It is shown how quasiperiodic structures determined by general nonlinear, or additive, functionals for generating functions and (effective) sources may transform black hole like configurations into cosmological metrics and inversely. We speculate on possible implications of quasiperiodic solutions in dark energy and dark matter physics. Finally, it is concluded that geometric methods for constructing exact solutions consist an important alternative tool to numerical relativity for investigating nonlinear effects in astrophysics and cosmology.

  20. Planar waveguide structure formed on Nd:YVO{sub 4} by Kr{sup 8+} ion irradiation at ultralow fluences

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Lian; Liu, Peng; Liu, Tao; Zhou, Yu-Fan [School of Physics, State Key Laboratory of Crystal Materials and Key Laboratory of Particle and Particle Irradiation (MOE), Shandong University, Jinan 250100 (China); Sun, Jian-Rong; Wang, Zhi-Guang [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Wang, Xue-Lin, E-mail: xuelinwang@sdu.edu.cn [School of Physics, State Key Laboratory of Crystal Materials and Key Laboratory of Particle and Particle Irradiation (MOE), Shandong University, Jinan 250100 (China)

    2013-11-15

    We report on the fabrication of a planar waveguide structure on Nd:YVO{sub 4} laser crystal. The waveguide structure was formed by Kr{sup 8+} ion irradiation with energy of 30 MeV at fluences of 2 × 10{sup 12} cm{sup −2}. The guiding modes of the planar waveguide were measured by the prism-coupling method at wavelengths of 633 nm and 1539 nm. The reflectivity calculation method (RCM) was used to reconstruct the refractive index profiles. Relatively large positive changes in the ordinary refractive index occur in the waveguide region. The refractive index profile of the planar waveguide was a typical “well” + “barrier” distribution, and we used the finite-difference beam propagation method (FD-BPM) to simulate light propagation in the waveguide. Using the Stopping and Range of Ions in Matter (SRIM 2008) software, the energy loss during ion irradiation was simulated to obtain a better understanding of the formation of the waveguide structure. The investigation of the absorption bands demonstrated that the transmission properties of the bulk Nd:YVO{sub 4} crystal have been preserved after ion irradiation.

  1. High performances of dual network PVA hydrogel modified by PVP using borax as the structure-forming accelerator.

    Science.gov (United States)

    Huang, Min; Hou, Yi; Li, Yubao; Wang, Danqing; Zhang, Li

    2017-01-01

    A dual network hydrogel made up of polyvinylalcohol (PVA) crosslinked by borax and polyvinylpyrrolidone (PVP) was prepared by means of freezing-thawing circles. Here PVP was incorporated by linking with PVA to form a network structure, while the introduction of borax played the role of crosslinking PVA chains to accelerate the formation of a dual network structure in PVA/PVP composite hydrogel, thus endowing the hydrogel with high mechanical properties. The effects of both PVP and borax on the hydrogels were evaluated by comparing the two systems of PVA/PVP/borax and PVA/borax hydrogels. In the former system, adding 4.0% PVP not only increased the water content and the storage modulus but also enhanced the mechanical strength of the final hydrogel. But an overdose of PVP just as more than 4.0% tended to undermine the structure of hydrogels, and thus deteriorated hydrogels' properties because of the weakened secondary interaction between PVP and PVA. Likewise, increasing borax could promote the gel crosslinking degree, thus making gels show a decrease in water content and swelling ratio, meanwhile shrinking the pores inside the hydrogels and finally enhancing the mechanical strength of hydrogels prominently. The developed hydrogel with high performances holds great potential for applications in biomedical and industrial fields.

  2. Ultra-high resolution X-ray structures of two forms of human recombinant insulin at 100 K.

    Science.gov (United States)

    Lisgarten, David R; Palmer, Rex A; Lobley, Carina M C; Naylor, Claire E; Chowdhry, Babur Z; Al-Kurdi, Zakieh I; Badwan, Adnan A; Howlin, Brendan J; Gibbons, Nicholas C J; Saldanha, José W; Lisgarten, John N; Basak, Ajit K

    2017-08-01

    The crystal structure of a commercially available form of human recombinant (HR) insulin, Insugen (I), used in the treatment of diabetes has been determined to 0.92 Å resolution using low temperature, 100 K, synchrotron X-ray data collected at 16,000 keV (λ = 0.77 Å). Refinement carried out with anisotropic displacement parameters, removal of main-chain stereochemical restraints, inclusion of H atoms in calculated positions, and 220 water molecules, converged to a final value of R = 0.1112 and R free  = 0.1466. The structure includes what is thought to be an ordered propanol molecule (POL) only in chain D(4) and a solvated acetate molecule (ACT) coordinated to the Zn atom only in chain B(2). Possible origins and consequences of the propanol and acetate molecules are discussed. Three types of amino acid representation in the electron density are examined in detail: (i) sharp with very clearly resolved features; (ii) well resolved but clearly divided into two conformations which are well behaved in the refinement, both having high quality geometry; (iii) poor density and difficult or impossible to model. An example of type (ii) is observed for the intra-chain disulphide bridge in chain C(3) between Sγ6-Sγ11 which has two clear conformations with relative refined occupancies of 0.8 and 0.2, respectively. In contrast the corresponding S-S bridge in chain A(1) shows one clearly defined conformation. A molecular dynamics study has provided a rational explanation of this difference between chains A and C. More generally, differences in the electron density features between corresponding residues in chains A and C and chains B and D is a common observation in the Insugen (I) structure and these effects are discussed in detail. The crystal structure, also at 0.92 Å and 100 K, of a second commercially available form of human recombinant insulin, Intergen (II), deposited in the Protein Data Bank as 3W7Y which remains otherwise unpublished is compared here

  3. Teaching Form as Form

    DEFF Research Database (Denmark)

    Keiding, Tina Bering

    2012-01-01

    understanding of form per se, or, to use an expression from this text, of form as form. This challenge can be reduced to one question: how can design teaching support students in achieving not only the ability to recognize and describe different form-related concepts in existing design (i.e. analytical...

  4. Mechanism of growth, composition and structure of oxide films formed on ferrous alloys in molten salt electrolytes - a review

    International Nuclear Information System (INIS)

    Tzvetkoff, Tz.; Kolchakov, J.

    2004-01-01

    The growth kinetics, chemical composition and structure of scales formed during corrosion of Fe and its alloys in molten salts are reviewed. Special attention is paid to the effect of the composition of the molten salt mixture and the gas atmosphere on the stability and protective ability of corrosion layers. First, the thermodynamical background of the corrosion and oxidation of Fe-base engineering materials in molten salt media is briefly commented. A concise review of the growth kinetics of passivating oxide films is also presented. These two introductory chapters serve as a guide for the extensive survey of the growth mechanism, nature and properties of oxide and related scales on ferrous alloys in a range of molten electrolytes - chlorides, nitrates, sulphates, carbonates, hydroxides and mixtures thereof in gas atmospheres containing O 2 , CO 2 , SO 2 , SO 3 and HCl

  5. Chemical composition and electronic structure of the passive layer formed on stainless steels in a glucose-oxidase solution

    Energy Technology Data Exchange (ETDEWEB)

    Marconnet, C. [Laboratoire de Genie des Procedes et des Materiaux, Ecole Centrale Paris, Grande Voie des Vignes, 92290 CHATENAY-MALABRY (France)], E-mail: cyril.marconnet@yahoo.fr; Wouters, Y. [Science et Ingenierie des Materiaux et Procedes, Institut National Polytechnique de Grenoble, F-38402 Saint-Martin d' Heres Cedex (France); Miserque, F. [Laboratoire de Reactivite des Surfaces et des Interfaces, CEA Saclay, Bat. 391, 91191 GIF-SUR-YVETTE (France); Dagbert, C. [Laboratoire de Genie des Procedes et des Materiaux, Ecole Centrale Paris, Grande Voie des Vignes, 92290 CHATENAY-MALABRY (France)], E-mail: catherine.dagbert@ecp.fr; Petit, J.-P. [Laboratoire d' Electrochimie et de Physico-chimie des Materiaux et des Interfaces, INPG, F-38402 Saint-Martin d' Heres Cedex (France); Galerie, A. [Science et Ingenierie des Materiaux et Procedes, Institut National Polytechnique de Grenoble, F-38402 Saint-Martin d' Heres Cedex (France); Feron, D. [Service de Corrosion et du Comportement des Materiaux dans leur Environnement, CEA Saclay, Bat. 458, 91191 GIF-SUR-YVETTE (France)

    2008-12-01

    This article deals with the interaction between the passive layer formed on UNS S30403 and S31254 stainless steels and an enzymatic solution containing glucose oxidase (GOx) and its substrate D-glucose. This enzymatic solution is often used to reproduce in laboratory the ennoblement occuring in non-sterile aerated aqueous environments because of the biofilm settlement on the surface of the metallic material. GOx catalyses the oxidation of D-glucose to gluconic acid by reducing oxygen to hydrogen peroxide and produces an organic acid. Thanks to photocurrent measurements, XPS analysis and Mott-Schottky diagrams, it is here shown that such an environment generates modifications in the chemical composition and electronic structure of the passive layer: it induces a relative enrichment of the n-type semi-conducting phase containing chromium (chromine Cr{sub 2}O{sub 3}) and an increase of the donors density in the space charge region.

  6. Chemical composition and electronic structure of the passive layer formed on stainless steels in a glucose-oxidase solution

    International Nuclear Information System (INIS)

    Marconnet, C.; Wouters, Y.; Miserque, F.; Dagbert, C.; Petit, J.-P.; Galerie, A.; Feron, D.

    2008-01-01

    This article deals with the interaction between the passive layer formed on UNS S30403 and S31254 stainless steels and an enzymatic solution containing glucose oxidase (GOx) and its substrate D-glucose. This enzymatic solution is often used to reproduce in laboratory the ennoblement occuring in non-sterile aerated aqueous environments because of the biofilm settlement on the surface of the metallic material. GOx catalyses the oxidation of D-glucose to gluconic acid by reducing oxygen to hydrogen peroxide and produces an organic acid. Thanks to photocurrent measurements, XPS analysis and Mott-Schottky diagrams, it is here shown that such an environment generates modifications in the chemical composition and electronic structure of the passive layer: it induces a relative enrichment of the n-type semi-conducting phase containing chromium (chromine Cr 2 O 3 ) and an increase of the donors density in the space charge region

  7. FORMA Y VARIACIÓN EN LA ESTRUCTURA DE ALDEA BALINESA / Form and variation in a balinese village structure

    Directory of Open Access Journals (Sweden)

    Clifford Geertz

    2013-07-01

    Full Text Available El texto originalmente apareció bajo el título "Form and variation in a balinese village structure", en American Anthropologist, New Series, Vol. 61, N° 6 (Diciembre de 1959, pp. 991-1012. Agradecemos a American Anthropologist por la autorización a publicar esta traducción. Elegimos traducir y editar este texto de Clifford Geertz en la RMA, por considerarlo una pieza clave para los debates de la “era estructuralista”, por sus cualidades intrínsecas y su trascendencia para la teoría – etnografía, así como por tratarse de un texto primario de un autor fundamental.

  8. The structural evolution of Milky-Way-like star-forming galaxies since z ∼ 1.3

    International Nuclear Information System (INIS)

    Patel, Shannon G.; Fumagalli, Mattia; Franx, Marijn; Labbé, Ivo; Muzzin, Adam; Van Dokkum, Pieter G.; Leja, Joel; Skelton, Rosalind E.; Momcheva, Ivelina; Nelson, Erica June; Van der Wel, Arjen; Rix, Hans-Walter; Brammer, Gabriel; Whitaker, Katherine E.; Lundgren, Britt; Wake, David A.; Quadri, Ryan F.

    2013-01-01

    We follow the structural evolution of star-forming galaxies (SFGs) like the Milky Way by selecting progenitors to z ∼ 1.3 based on the stellar mass growth inferred from the evolution of the star-forming sequence. We select our sample from the 3D-HST survey, which utilizes spectroscopy from the HST/WFC3 G141 near-IR grism and enables precise redshift measurements for our sample of SFGs. Structural properties are obtained from Sérsic profile fits to CANDELS WFC3 imaging. The progenitors of z = 0 SFGs with stellar mass M = 10 10.5 M ☉ are typically half as massive at z ∼ 1. This late-time stellar mass growth is consistent with recent studies that employ abundance matching techniques. The descendant SFGs at z ∼ 0 have grown in half-light radius by a factor of ∼1.4 since z ∼ 1. The half-light radius grows with stellar mass as r e ∝M 0.29 . While most of the stellar mass is clearly assembling at large radii, the mass surface density profiles reveal ongoing mass growth also in the central regions where bulges and pseudobulges are common features in present day late-type galaxies. Some portion of this growth in the central regions is due to star formation as recent observations of Hα maps for SFGs at z ∼ 1 are found to be extended but centrally peaked. Connecting our lookback study with galactic archeology, we find the stellar mass surface density at R = 8 kpc to have increased by a factor of ∼2 since z ∼ 1, in good agreement with measurements derived for the solar neighborhood of the Milky Way.

  9. Atomic Scale Investigation of Structural Properties and Glass Forming Ability of Ti100- x Al x Metallic Glasses

    Science.gov (United States)

    Tahiri, M.; Hasnaoui, A.; Sbiaai, K.

    2018-06-01

    In this work, we employed molecular dynamics (MD) simulations to study Ti-Al metallic glasses (MGs) using the embedded atom method (EAM) potential to model the atomic interaction with different compositions. The results showed evidence of the metallic glass formation induced by the split occurring in the second peak of the radial distribution function (RDF) curves implying both Ti and Al atoms. The common neighbor analysis (CNA) method confirmed the presence of the icosahedral clusters with a maximum amount observed for an alloy with 75 pct of Al. Analysis of coordination numbers (CNs) indicated that the total CNs are nearly unchanged in these systems. Finally, Voronoi tessellation analyses (VTA) showed a higher value of the number of icosahedral units at Ti25Al75 composition. This specific composition represents a nearby peritectic point localized at a low melting point in the Ti-Al binary phase diagram. The glass forming ability (GFA) becomes important when the fraction of Al increases by forming and connecting "icosahedral-like" clusters (12-coordinated and 13-coordinated ) and by playing a main role in the structure stability of the Ti-Al MGs.

  10. The Iranian version of 12-item Short Form Health Survey (SF-12: factor structure, internal consistency and construct validity

    Directory of Open Access Journals (Sweden)

    Mousavi Sayed

    2009-09-01

    Full Text Available Abstract Background The 12-item Short Form Health Survey (SF-12 as a shorter alternative of the SF-36 is largely used in health outcomes surveys. The aim of this study was to validate the SF-12 in Iran. Methods A random sample of the general population aged 15 years and over living in Tehran, Iran completed the SF-12. Reliability was estimated using internal consistency and validity was assessed using known groups comparison and convergent validity. In addition, the factor structure of the questionnaire was extracted by performing both exploratory factor analysis (EFA and confirmatory factor analysis (CFA. Results: In all, 5587 individuals were studied (2721 male and 2866 female. The mean age and formal education of the respondents were 35.1 (SD = 15.4 and 10.2 (SD = 4.4 years respectively. The results showed satisfactory internal consistency for both summary measures, that are the Physical Component Summary (PCS and the Mental Component Summary (MCS; Cronbach's α for PCS-12 and MCS-12 was 0.73 and 0.72, respectively. Known-groups comparison showed that the SF-12 discriminated well between men and women and those who differed in age and educational status (P Conclusion In general the findings suggest that the SF-12 is a reliable and valid measure of health related quality of life among Iranian population. However, further studies are needed to establish stronger psychometric properties for this alternative form of the SF-36 Health Survey in Iran.

  11. Analysis of sulfidic linkages formed in natural rubber latex medical gloves by using X-ray absorption near edge structure

    Science.gov (United States)

    Chankrachang, M.; Limphirat, W.; Yongyingsakthavorn, P.; Nontakaew, U.; Tohsan, A.

    2017-09-01

    A study of sulfidic linkages formed in natural rubber (NR) latex medical gloves by using X-ray Absorption Near Edge Structure (XANES) is presented in this paper. The NR latex compound was prepared by using prevulcanization method, that is, it was prevulcanized at room temperature for 24 hrs before utilization. After the 24 hrs of prevulcanization, the latex film samples were obtained by dipping process. The dipped films were subjected to vulcanize at 110°C for 5 to 25 min. It was observed that after the compound was prevulcanized for 24 hrs, polysulfidic linkages were mainly formed in the sample. It was however found that after curing at 110°C for 5-25 min, the polysulfidic linkages are tended to change into disulfide linkages. Especially, in the case of 25 minutes cured sample, disulfide linkages are found to be the main linkages. In term of tensile strength, it was observed that when cure time increased from 5 - 10 min, tensile strengths were also increased. But when the cure time of the film is 25 minutes, tensile strength was slightly dropped. The dropped of tensile strength when cure time is longer than 10 minutes can be ascribed to a degradation of polysulfidic and disulfidic linkages during curing. Therefore, by using XANES analysis, it was found to be very useful to understand the cure characteristic, thus it can be very helpful to optimize cure time and tensile properties of the product.

  12. Atomic Scale Investigation of Structural Properties and Glass Forming Ability of Ti100-x Al x Metallic Glasses

    Science.gov (United States)

    Tahiri, M.; Hasnaoui, A.; Sbiaai, K.

    2018-03-01

    In this work, we employed molecular dynamics (MD) simulations to study Ti-Al metallic glasses (MGs) using the embedded atom method (EAM) potential to model the atomic interaction with different compositions. The results showed evidence of the metallic glass formation induced by the split occurring in the second peak of the radial distribution function (RDF) curves implying both Ti and Al atoms. The common neighbor analysis (CNA) method confirmed the presence of the icosahedral clusters with a maximum amount observed for an alloy with 75 pct of Al. Analysis of coordination numbers (CNs) indicated that the total CNs are nearly unchanged in these systems. Finally, Voronoi tessellation analyses (VTA) showed a higher value of the number of icosahedral units at Ti25Al75 composition. This specific composition represents a nearby peritectic point localized at a low melting point in the Ti-Al binary phase diagram. The glass forming ability (GFA) becomes important when the fraction of Al increases by forming and connecting "icosahedral-like" clusters (12-coordinated and 13-coordinated ) and by playing a main role in the structure stability of the Ti-Al MGs.

  13. Investigation of Antileishmanial Activities of Acridines Derivatives against Promastigotes and Amastigotes Form of Parasites Using Quantitative Structure Activity Relationship Analysis

    Directory of Open Access Journals (Sweden)

    Samir Chtita

    2016-01-01

    Full Text Available In a search of newer and potent antileishmanial (against promastigotes and amastigotes form of parasites drug, a series of 60 variously substituted acridines derivatives were subjected to a quantitative structure activity relationship (QSAR analysis for studying, interpreting, and predicting activities and designing new compounds by using multiple linear regression and artificial neural network (ANN methods. The used descriptors were computed with Gaussian 03, ACD/ChemSketch, Marvin Sketch, and ChemOffice programs. The QSAR models developed were validated according to the principles set up by the Organisation for Economic Co-operation and Development (OECD. The principal component analysis (PCA has been used to select descriptors that show a high correlation with activities. The univariate partitioning (UP method was used to divide the dataset into training and test sets. The multiple linear regression (MLR method showed a correlation coefficient of 0.850 and 0.814 for antileishmanial activities against promastigotes and amastigotes forms of parasites, respectively. Internal and external validations were used to determine the statistical quality of QSAR of the two MLR models. The artificial neural network (ANN method, considering the relevant descriptors obtained from the MLR, showed a correlation coefficient of 0.933 and 0.918 with 7-3-1 and 6-3-1 ANN models architecture for antileishmanial activities against promastigotes and amastigotes forms of parasites, respectively. The applicability domain of MLR models was investigated using simple and leverage approaches to detect outliers and outsides compounds. The effects of different descriptors in the activities were described and used to study and design new compounds with higher activities compared to the existing ones.

  14. Roles of viroplasm-like structures formed by nonstructural protein NSs in infection with severe fever with thrombocytopenia syndrome virus.

    Science.gov (United States)

    Wu, Xiaodong; Qi, Xian; Liang, Mifang; Li, Chuan; Cardona, Carol J; Li, Dexin; Xing, Zheng

    2014-06-01

    Severe fever with thrombocytopenia syndrome (SFTS) virus is an emerging bunyavirus that causes a hemorrhagic fever with a high mortality rate. The virus is likely tick-borne and replicates primarily in hemopoietic cells, which may lead to disregulation of proinflammatory cytokine induction and loss of leukocytes and platelets. The viral genome contains L, M, and S segments encoding a viral RNA polymerase, glycoproteins G(n) and G(c), nucleoprotein (NP), and a nonstructural S segment (NSs) protein. NSs protein is involved in the regulation of host innate immune responses and suppression of IFNβ-promoter activities. In this article, we demonstrate that NSs protein can form viroplasm-like structures (VLSs) in infected and transfected cells. NSs protein molecules interact with one another, interact with NP, and were associated with viral RNA in infected cells, suggesting that NSs protein may be involved in viral replication. Furthermore, we observed that NSs-formed VLS colocalized with lipid droplets and that inhibitors of fatty acid biosynthesis decreased VLS formation or viral replication in transfected and infected cells. Finally, we have demonstrated that viral dsRNAs were also localized in VLS in infected cells, suggesting that NSs-formed VLS may be implicated in the replication of SFTS bunyavirus. These findings identify a novel function of nonstructural NSs in SFTSV-infected cells where it is a scaffolding component in a VLS functioning as a virus replication factory. This function is in addition to the role of NSs protein in modulating host responses that will broaden our understanding of viral pathogenesis of phleboviruses. © FASEB.

  15. Multicultural counseling self-efficacy scale-racial diversity form: factor structure and test of a social cognitive model.

    Science.gov (United States)

    Sheu, Hung-Bin; Rigali-Oiler, Marybeth; Lent, Robert W

    2012-01-01

    This study was conducted to gather evidence on the factor structure and concurrent criterion validity of the multicultural counseling self-efficacy scale-racial diversity form (MCSE-RD; Sheu & Lent, 2007). The MCSE-RD was designed to assess therapists' perceived capabilities in performing culturally relevant in-session behaviors in cross-racial counseling. Participants were 209 students in counseling-related graduate programs in the USA. Confirmatory factor analyses identified a bifactor structure in which responses to MCSE-RD items could be explained by one generic and three multicultural-specific counseling self-efficacy factors. Support was also found for a social cognitive model in which self-efficacy and interests in multicultural counseling mediated the effects of prior cross-racial client contacts and perceptions of multicultural training environments on intent to perform multicultural counseling in the future. Additionally, outcome expectations were predictive of multicultural counseling interests and choice goals. Implications for multicultural training and directions for future research are highlighted.

  16. Ducks in space: from nonlinear absolute instability to noise-sustained structures in a pattern-forming system

    Science.gov (United States)

    Avitabile, D.; Desroches, M.; Knobloch, E.; Krupa, M.

    2017-11-01

    A subcritical pattern-forming system with nonlinear advection in a bounded domain is recast as a slow-fast system in space and studied using a combination of geometric singular perturbation theory and numerical continuation. Two types of solutions describing the possible location of stationary fronts are identified, whose origin is traced to the onset of convective and absolute instability when the system is unbounded. The former are present only for non-zero upstream boundary conditions and provide a quantitative understanding of noise-sustained structures in systems of this type. The latter correspond to the onset of a global mode and are present even with zero upstream boundary conditions. The role of canard trajectories in the nonlinear transition between these states is clarified and the stability properties of the resulting spatial structures are determined. Front location in the convective regime is highly sensitive to the upstream boundary condition, and its dependence on this boundary condition is studied using a combination of numerical continuation and Monte Carlo simulations of the partial differential equation. Statistical properties of the system subjected to random or stochastic boundary conditions at the inlet are interpreted using the deterministic slow-fast spatial dynamical system.

  17. Polarization Properties and Magnetic Field Structures in the High-mass Star-forming Region W51 Observed with ALMA

    Science.gov (United States)

    Koch, Patrick M.; Tang, Ya-Wen; Ho, Paul T. P.; Yen, Hsi-Wei; Su, Yu-Nung; Takakuwa, Shigehisa

    2018-03-01

    We present the first ALMA dust polarization observations toward the high-mass star-forming regions W51 e2, e8, and W51 North in Band 6 (230 GHz) with a resolution of about 0\\buildrel{\\prime\\prime}\\over{.} 26 (∼5 mpc). Polarized emission in all three sources is clearly detected and resolved. Measured relative polarization levels are between 0.1% and 10%. While the absolute polarization shows complicated structures, the relative polarization displays the typical anticorrelation with Stokes I, although with a large scatter. Inferred magnetic (B) field morphologies are organized and connected. Detailed substructures are resolved, revealing new features such as comet-shaped B-field morphologies in satellite cores, symmetrically converging B-field zones, and possibly streamlined morphologies. The local B-field dispersion shows some anticorrelation with the relative polarization. Moreover, the lowest polarization percentages together with largest dispersions coincide with B-field convergence zones. We put forward \\sin ω , where ω is the measurable angle between a local B-field orientation and local gravity, as a measure of how effectively the B field can oppose gravity. Maps of \\sin ω for all three sources show organized structures that suggest a locally varying role of the B field, with some regions where gravity can largely act unaffectedly, possibly in a network of narrow magnetic channels, and other regions where the B field can work maximally against gravity.

  18. A structural model of the pore-forming region of the skeletal muscle ryanodine receptor (RyR1.

    Directory of Open Access Journals (Sweden)

    Srinivas Ramachandran

    2009-04-01

    Full Text Available Ryanodine receptors (RyRs are ion channels that regulate muscle contraction by releasing calcium ions from intracellular stores into the cytoplasm. Mutations in skeletal muscle RyR (RyR1 give rise to congenital diseases such as central core disease. The absence of high-resolution structures of RyR1 has limited our understanding of channel function and disease mechanisms at the molecular level. Here, we report a structural model of the pore-forming region of RyR1. Molecular dynamics simulations show high ion binding to putative pore residues D4899, E4900, D4938, and D4945, which are experimentally known to be critical for channel conductance and selectivity. We also observe preferential localization of Ca(2+ over K(+ in the selectivity filter of RyR1. Simulations of RyR1-D4899Q mutant show a loss of preference to Ca(2+ in the selectivity filter as seen experimentally. Electrophysiological experiments on a central core disease mutant, RyR1-G4898R, show constitutively open channels that conduct K(+ but not Ca(2+. Our simulations with G4898R likewise show a decrease in the preference of Ca(2+ over K(+ in the selectivity filter. Together, the computational and experimental results shed light on ion conductance and selectivity of RyR1 at an atomistic level.

  19. The Iranian version of 12-item Short Form Health Survey (SF-12): factor structure, internal consistency and construct validity.

    Science.gov (United States)

    Montazeri, Ali; Vahdaninia, Mariam; Mousavi, Sayed Javad; Omidvari, Speideh

    2009-09-16

    The 12-item Short Form Health Survey (SF-12) as a shorter alternative of the SF-36 is largely used in health outcomes surveys. The aim of this study was to validate the SF-12 in Iran. A random sample of the general population aged 15 years and over living in Tehran, Iran completed the SF-12. Reliability was estimated using internal consistency and validity was assessed using known groups comparison and convergent validity. In addition, the factor structure of the questionnaire was extracted by performing both exploratory factor analysis (EFA) and confirmatory factor analysis (CFA). In all, 5587 individuals were studied (2721 male and 2866 female). The mean age and formal education of the respondents were 35.1 (SD = 15.4) and 10.2 (SD = 4.4) years respectively. The results showed satisfactory internal consistency for both summary measures, that are the Physical Component Summary (PCS) and the Mental Component Summary (MCS); Cronbach's alpha for PCS-12 and MCS-12 was 0.73 and 0.72, respectively. Known-groups comparison showed that the SF-12 discriminated well between men and women and those who differed in age and educational status (P < 0.001). In addition, correlations between the SF-12 scales and single items showed that the physical functioning, role physical, bodily pain and general health subscales correlated higher with the PCS-12 score, while the vitality, social functioning, role emotional and mental health subscales more correlated with the MCS-12 score lending support to its good convergent validity. Finally the principal component analysis indicated a two-factor structure (physical and mental health) that jointly accounted for 57.8% of the variance. The confirmatory factory analysis also indicated a good fit to the data for the two-latent structure (physical and mental health). In general the findings suggest that the SF-12 is a reliable and valid measure of health related quality of life among Iranian population. However, further studies are needed to

  20. Structural analysis of salt cavities formed by solution mining: I. Method of analysis and preliminary results for spherical cavities

    International Nuclear Information System (INIS)

    Fossum, A.F.

    1976-01-01

    The primary objective of this effort is an analysis of the structural stability of cavities formed by solution mining in salt domes. In particular, the effects of depth (i.e. initial state of in situ stress), shape, volume (i.e. physical dimensions of the cavity), and sequence of salt excavation/fluid evacuation on the timewise structural stability of a cavity are of interest. It is anticipated that an assessment can be made of the interrelation between depth, cavern size, and cavern shape or of the practical limits therewith. In general, the cavity shape is assumed to be axisymmetric and the salt is assumed to exhibit nonlinear creep behavior. The primary emphasis is placed on the methodology of the finite element analysis, and the results of preliminary calculations for a spherically shaped cavity. It is common practice for engineers to apply elasticity theory to the behavior of rock in order to obtain near field stresses and displacements around an underground excavation in an effort to assess structural stability. Rock masses, particularly at depth, may be subjected to a rather complex state of initial stress, and may be nonhomogeneous and anisotropic. If one also includes complex geometrical excavation shape, the use of analytical techniques as an analysis tool is practically impossible. Thus, it is almost a necessity that approximate solution techniques be employed. In this regard, the finite element method is ideal as it can handle complex geometries and nonlinear material behavior with relative ease. An unusual feature of the present study is the incorporation into the finite element code of a procedure for handling the gradual creation or excavation of an underground cavity. During the excavation sequence, the salt is permitted to exhibit nonlinear stress-strain-time dependence. The bulk of this report will be devoted to a description of the analysis procedures, together with a preliminary calculation for a spherically shaped cavity

  1. Acemetacin cocrystals and salts: structure solution from powder X-ray data and form selection of the piperazine salt

    Directory of Open Access Journals (Sweden)

    Palash Sanphui

    2014-03-01

    Full Text Available Acemetacin (ACM is a non-steroidal anti-inflammatory drug (NSAID, which causes reduced gastric damage compared with indomethacin. However, acemetacin has a tendency to form a less soluble hydrate in the aqueous medium. We noted difficulties in the preparation of cocrystals and salts of acemetacin by mechanochemical methods, because this drug tends to form a hydrate during any kind of solution-based processing. With the objective to discover a solid form of acemetacin that is stable in the aqueous medium, binary adducts were prepared by the melt method to avoid hydration. The coformers/salt formers reported are pyridine carboxamides [nicotinamide (NAM, isonicotinamide (INA, and picolinamide (PAM], caprolactam (CPR, p-aminobenzoic acid (PABA, and piperazine (PPZ. The structures of an ACM–INA cocrystal and a binary adduct ACM–PABA were solved using single-crystal X-ray diffraction. Other ACM cocrystals, ACM–PAM and ACM–CPR, and the piperazine salt ACM–PPZ were solved from high-resolution powder X-ray diffraction data. The ACM–INA cocrystal is sustained by the acid...pyridine heterosynthon and N—H...O catemer hydrogen bonds involving the amide group. The acid...amide heterosynthon is present in the ACM–PAM cocrystal, while ACM–CPR contains carboxamide dimers of caprolactam along with acid–carbonyl (ACM hydrogen bonds. The cocrystals ACM–INA, ACM–PAM and ACM–CPR are three-dimensional isostructural. The carboxyl...carboxyl synthon in ACM–PABA posed difficulty in assigning the position of the H atom, which may indicate proton disorder. In terms of stability, the salts were found to be relatively stable in pH 7 buffer medium over 24 h, but the cocrystals dissociated to give ACM hydrate during the same time period. The ACM–PPZ salt and ACM–nicotinamide cocrystal dissolve five times faster than the stable hydrate form, whereas the ACM–PABA adduct has 2.5 times faster dissolution rate. The pharmaceutically acceptable

  2. Acemetacin cocrystals and salts: structure solution from powder X-ray data and form selection of the piperazine salt.

    Science.gov (United States)

    Sanphui, Palash; Bolla, Geetha; Nangia, Ashwini; Chernyshev, Vladimir

    2014-03-01

    Acemetacin (ACM) is a non-steroidal anti-inflammatory drug (NSAID), which causes reduced gastric damage compared with indomethacin. However, acemetacin has a tendency to form a less soluble hydrate in the aqueous medium. We noted difficulties in the preparation of cocrystals and salts of acemetacin by mechanochemical methods, because this drug tends to form a hydrate during any kind of solution-based processing. With the objective to discover a solid form of acemetacin that is stable in the aqueous medium, binary adducts were prepared by the melt method to avoid hydration. The coformers/salt formers reported are pyridine carboxamides [nicotinamide (NAM), isonicotinamide (INA), and picolinamide (PAM)], caprolactam (CPR), p-aminobenzoic acid (PABA), and piperazine (PPZ). The structures of an ACM-INA cocrystal and a binary adduct ACM-PABA were solved using single-crystal X-ray diffraction. Other ACM cocrystals, ACM-PAM and ACM-CPR, and the piperazine salt ACM-PPZ were solved from high-resolution powder X-ray diffraction data. The ACM-INA cocrystal is sustained by the acid⋯pyridine heterosynthon and N-H⋯O catemer hydrogen bonds involving the amide group. The acid⋯amide heterosynthon is present in the ACM-PAM cocrystal, while ACM-CPR contains carboxamide dimers of caprolactam along with acid-carbonyl (ACM) hydrogen bonds. The cocrystals ACM-INA, ACM-PAM and ACM-CPR are three-dimensional isostructural. The carboxyl⋯carboxyl synthon in ACM-PABA posed difficulty in assigning the position of the H atom, which may indicate proton disorder. In terms of stability, the salts were found to be relatively stable in pH 7 buffer medium over 24 h, but the cocrystals dissociated to give ACM hydrate during the same time period. The ACM-PPZ salt and ACM-nicotinamide cocrystal dissolve five times faster than the stable hydrate form, whereas the ACM-PABA adduct has 2.5 times faster dissolution rate. The pharmaceutically acceptable piperazine salt of acemetacin exhibits superior

  3. Enhancement of heat transfer rate with structural modification of double pipe heat exchanger by changing cylindrical form of tubes into conical form

    International Nuclear Information System (INIS)

    Hashemian, Mehran; Jafarmadar, Samad; Nasiri, Javid; Sadighi Dizaji, Hamed

    2017-01-01

    Highlights: • An improved geometry is presented by changing tubes form into conical. • Enhancement of heat transfer rate is investigated. • Frictional characteristics for novel geometry are studied. • For a proper understanding of the subject, the exact physical interpretation is added. • The effect of flow, geometry and thermodynamic parameters is considered. - Abstract: In this paper, cylindrical tubes of a double pipe heat exchanger were changed into the conical tubes as an innovative design which causes improvement of thermal performance of heat exchanger without increment of its weight. Utilization of conical tube instead of cylindrical tube can impress both thermal and frictional characteristics of heat exchanger. Hence, the effect of conical tubes on Nusselt number, friction factor and thermal performance factor are evaluated in present research which was not covered already. Moreover, the effects of hydrodynamic, thermodynamic and geometrical characteristics are analyzed. All said parameters are numerically investigated for nine different combinations of flow direction and conical tubes geometry. The results of simulations of the said configurations are presented to compare the cases from different points of view and determine the most thermally efficient case. The results reveal modified geometry makes 63% increment in Nu number and 54% increment in heat transfer rate at optimum condition.

  4. Structure of light mass (exotic) nuclei as evidenced by scattering from hydrogen

    International Nuclear Information System (INIS)

    Amos, K.; Dortmans, P.J.

    1998-01-01

    Microscopic optical model potentials generated by full folding of realistic two-nucleon (n/N) interactions with nuclear structure specified by large basis shell model calculations have been constructed. With those (nonlocal) optical potentials, predictions of light mass nuclei-hydrogen scattering were obtained at intermediate energies (65 to 800 MeV) that agree well with observations of cross sections and analyzing powers

  5. Joint Convention on the Safety of Spent Fuel Management and on the Safety of Radioactive Waste Management. Guidelines regarding the Form and Structure of National Reports

    International Nuclear Information System (INIS)

    2006-01-01

    The 'Guidelines regarding the Form and Structure of National Reports' adopted at the Preparatory Meeting of the Contracting Parties to the Joint Convention held from 10 to 12 December 2001 were modified at the Second Review Meeting of the Contracting Parties held from 15 to 24 May 2006. The modified 'Guidelines regarding the Form and Structure of National Reports' are set forth in the Attachment hereto

  6. Processes for forming exoergic structures with the use of a plasma and for producing dense refractory bodies of arbitrary shape therefrom

    International Nuclear Information System (INIS)

    Holt, J.B.; Kelly, M.D.

    1990-01-01

    Plasma spraying methods of forming exoergic structures and coatings, as well as exoergic structures produced by such methods, are presented. The methods include the plasma spraying of reactive exoergic materials that are capable of sustaining a combustion synthesis reaction onto a flat substrate or into molds of arbitrary shape and igniting the plasma sprayed materials, either under an inert gas pressure or not, to form refractory materials of varying densities and of varying shapes

  7. The structure of apo and holo forms of xylose reductase, a dimeric aldo-keto reductase from Candida tenuis.

    Science.gov (United States)

    Kavanagh, Kathryn L; Klimacek, Mario; Nidetzky, Bernd; Wilson, David K

    2002-07-16

    Xylose reductase is a homodimeric oxidoreductase dependent on NADPH or NADH and belongs to the largely monomeric aldo-keto reductase superfamily of proteins. It catalyzes the first step in the assimilation of xylose, an aldose found to be a major constituent monosaccharide of renewable plant hemicellulosic material, into yeast metabolic pathways. It does this by reducing open chain xylose to xylitol, which is reoxidized to xylulose by xylitol dehydrogenase and metabolically integrated via the pentose phosphate pathway. No structure has yet been determined for a xylose reductase, a dimeric aldo-keto reductase or a family 2 aldo-keto reductase. The structures of the Candida tenuis xylose reductase apo- and holoenzyme, which crystallize in spacegroup C2 with different unit cells, have been determined to 2.2 A resolution and an R-factor of 17.9 and 20.8%, respectively. Residues responsible for mediating the novel dimeric interface include Asp-178, Arg-181, Lys-202, Phe-206, Trp-313, and Pro-319. Alignments with other superfamily members indicate that these interactions are conserved in other dimeric xylose reductases but not throughout the remainder of the oligomeric aldo-keto reductases, predicting alternate modes of oligomerization for other families. An arrangement of side chains in a catalytic triad shows that Tyr-52 has a conserved function as a general acid. The loop that folds over the NAD(P)H cosubstrate is disordered in the apo form but becomes ordered upon cosubstrate binding. A slow conformational isomerization of this loop probably accounts for the observed rate-limiting step involving release of cosubstrate. Xylose binding (K(m) = 87 mM) is mediated by interactions with a binding pocket that is more polar than a typical aldo-keto reductase. Modeling of xylose into the active site of the holoenzyme using ordered waters as a guide for sugar hydroxyls suggests a convincing mode of substrate binding.

  8. Social structure of the harem-forming promiscuous fruit bat, Cynopterus sphinx, is the harem truly important?

    Science.gov (United States)

    Garg, Kritika M; Chattopadhyay, Balaji; Ramakrishnan, Uma

    2018-02-01

    Bats are social animals and display a diverse variety of mating and social systems, with most species exhibiting some form of polygyny. Their social organization is fluid and individuals frequently switch partners and roosting sites. While harem-like social organization is observed in multiple tropical species, its importance is contested in many of them. In this study, we investigated the role of harems in the social organization of the old world fruit bat Cynopterus sphinx . Based on regular behavioural observations over a period of 20 months and genetic data from microsatellite markers, we observed that the social organization is flexible, individuals regularly shift between roosts and the social organization resembles a fission-fusion society. Behavioural and genetic analyses suggest that the harems are not strict units of social structure, and the colony does not show signatures of subdivision with harems as behavioural units. We also observed that there was no correlation between individuals with high association index and pairwise relatedness. Our findings indicate that similar to the mating system, the social organization of C. sphinx can also be categorized as a fission-fusion society, and hence the term 'harem' is a misnomer. We conclude that the social system of C. sphinx is flexible, with multi-male multi-female organization, and individuals tend to be loyal to a given area rather than a roost.

  9. Water-limiting conditions alter the structure and biofilm-forming ability of bacterial multispecies communities in the alfalfa rhizosphere.

    Directory of Open Access Journals (Sweden)

    Pablo Bogino

    Full Text Available Biofilms are microbial communities that adhere to biotic or abiotic surfaces and are enclosed in a protective matrix of extracellular compounds. An important advantage of the biofilm lifestyle for soil bacteria (rhizobacteria is protection against water deprivation (desiccation or osmotic effect. The rhizosphere is a crucial microhabitat for ecological, interactive, and agricultural production processes. The composition and functions of bacterial biofilms in soil microniches are poorly understood. We studied multibacterial communities established as biofilm-like structures in the rhizosphere of Medicago sativa (alfalfa exposed to 3 experimental conditions of water limitation. The whole biofilm-forming ability (WBFA for rhizospheric communities exposed to desiccation was higher than that of communities exposed to saline or nonstressful conditions. A culture-dependent ribotyping analysis indicated that communities exposed to desiccation or saline conditions were more diverse than those under the nonstressful condition. 16S rRNA gene sequencing of selected strains showed that the rhizospheric communities consisted primarily of members of the Actinobacteria and α- and γ-Proteobacteria, regardless of the water-limiting condition. Our findings contribute to improved understanding of the effects of environmental stress factors on plant-bacteria interaction processes and have potential application to agricultural management practices.

  10. Endosulfine, endogenous ligand for the sulphonylurea receptor: isolation from porcine brain and partial structural determination of the alpha form.

    Science.gov (United States)

    Virsolvy-Vergine, A; Salazar, G; Sillard, R; Denoroy, L; Mutt, V; Bataille, D

    1996-02-01

    Anti-diabetic sulphonylureas act via high affinity binding sites coupled to K-ATP channels. Endosulfine, an endogenous ligand for these binding sites, was shown to exist in two molecular forms, alpha and beta, in both the pancreas and the central nervous system. We describe here the isolation, and partial structural characterization of alpha endosulfine derived from porcine brains by means of a series of chromatography runs and gel electrophoresis. Porcine alpha endosulfine is a protein with a molecular mass of 13,196 daltons as determined by mass spectrometry and which is N-terminally blocked. Tryptic digestion followed by separation of the fragments by HPLC and automated Edman degradation yielded a total of 72 amino acids in four partial sequences. Comparison of these sequences with that present in the National Biomedical Research Foundation protein data bank indicated a 82% identity with a 112-amino acid protein with a molecular mass of 12,353 daltons called "cyclic AMP-regulated phosphoprotein-19', isolated from the bovine brain as a substrate for protein kinase A.

  11. Structural properties of films and rheology of film-forming solutions of chitosan gallate for food packaging.

    Science.gov (United States)

    Wu, Chunhua; Tian, Jinhu; Li, Shan; Wu, Tiantian; Hu, Yaqin; Chen, Shiguo; Sugawara, Tatsuya; Ye, Xingqian

    2016-08-01

    The chitosan gallates (CG) were obtained by free-radical-initiated grafting of gallic acid (GA) onto chitosan (CS) in this work. The chemical structures of the CG were corroborated by UV-vis, GPC and (1)H NMR analysis. The grafting reaction was accompanied with a degradation of the CS molecule. The shear-thinning flow behavior of CG film-forming solutions (CG FFS) decreased with the grafting amount of GA into CS chain, while the CG FFS grafted at a lower GA value behaved like a networks containing entangled or cross-linked polymer chains with a more elastic behavior. The increasing of GA grafting onto the CS chain led to a reduction of tensile strength, elongation at break and water resistance in the corresponding films, but increases in the antioxidant and antimicrobial activities were observed. The microstructure of the film was investigated using scanning electron and atomic force microscope, and the results were closely related to the observed film properties. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Structural and optical properties of Cu-doped ZnS nanoparticles formed in chitosan/sodium alginate multilayer films.

    Science.gov (United States)

    Wang, Liping; Sun, Yujie; Xie, Xiaodong

    2014-05-01

    Chitosan/alginate multilayers were fabricated using a spin-coating method, and ZnS:Cu nanoparticles were generated within the network of two natural polysaccharides, chitosan and sodium alginate. The synthesized nanoparticles were characterized using an X-ray diffractometer (XRD), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS) and atomic force microscopy (AFM). The results showed that cubic zinc blende-structured ZnS:Cu nanoparticles with an average crystal size of ~ 3 nm were uniformly distributed. UV-vis spectra indicate a large quantum size effect and the absorption edge for the ZnS:Cu nanoparticles slightly shifted to longer wavelengths with increasing Cu ion concentrations. The photoluminescence of the Cu-doped ZnS nanoparticles reached a maximum at a 1% doping level. The ZnS:Cu nanoparticles form and are distributed uniformly in the composite multilayer films with a surface average height of 25 nm. Copyright © 2013 John Wiley & Sons, Ltd.

  13. Quantum chemical studies on molecular structural conformations and hydrated forms of salicylamide and O-hydroxybenzoyl cyanide

    Science.gov (United States)

    Anandan, K.; Kolandaivel, P.; Kumaresan, R.

    Ab initio and density functional theory (DFT) methods have been employed to study the molecular structural conformations and hydrated forms of both salicylamide (SAM) and O-hydroxybenzoyl cyanide (OHBC). Molecular geometries and energetics have been obtained in the gaseous phase by employing the Møller-Plesset type 2 MP2/6-311G(2d,2p) and B3LYP/6-311G(2d,2p) levels of theory. The presence of an electron-releasing group (SAM) leads to an increase in the energy of the molecular system, while the presence of an electron-withdrawing group (OHBC) drastically decreases the energy. Chemical reactivity parameters (η and μ) have been calculated using the energy values of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) obtained at the Hartree-Fock (HF)/6-311G(2d,2p) level of theory for all the conformers and the principle of maximum hardness (MHP) has been tested. The condensed Fukui functions have been calculated using the atomic charges obtained through the natural bond orbital (NBO) analysis scheme for all the optimized structures at the B3LYP/6-311G(2d,2p) level of theory, and the most reactive sites of the molecules have been identified. Nuclear magnetic resonance (NMR) studies have been carried out at the B3LYP/6-311G(2d,2p) level of theory for all the conformers in the gaseous phase on the basis of the method of Cheeseman and coworkers. The calculated chemical shift values have been used to discuss the delocalization activity of the electron clouds. The dimeric structures of the most stable conformers of both SAM and OHBC in the gaseous phase have been optimized at the B3LYP/6-311G(2d,2p) level of theory, and the interaction energies have been calculated. The most stable conformers of both compounds bear an intramolecular hydrogen bond, which gives rise to the formation of a pseudo-aromatic ring. These conformers have been allowed to interact with the water molecule. Special emphasis has been given to analysis of the

  14. Skyrme-model πNN form factor and nucleon-nucleon interaction

    International Nuclear Information System (INIS)

    Holzwarth, G.; Machleidt, R.

    1997-01-01

    We apply the strong πNN form factor, which emerges from the Skyrme model, in the two-nucleon system using a one-boson-exchange (OBE) model for the nucleon-nucleon (NN) interaction. Deuteron properties and phase parameters of NN scattering are reproduced well. In contrast to the form factor of monopole shape that is traditionally used in OBE models, the Skyrme form factor leaves low-momentum transfers essentially unaffected while it suppresses the high-momentum region strongly. It turns out that this behavior is very appropriate for models of the NN interaction and makes it possible to use a soft pion form factor in the NN system. As a consequence, the πN and the NN systems can be described using the same πNN form factor, which is impossible with the monopole. copyright 1997 The American Physical Society

  15. Annual research review: phenotypic and causal structure of conduct disorder in the broader context of prevalent forms of psychopathology.

    Science.gov (United States)

    Lahey, Benjamin B; Waldman, Irwin D

    2012-05-01

    A better understanding of the nature and etiology of conduct disorder (CD) can inform nosology and vice versa. We posit that any prevalent form of psychopathology, including CD, can be best understood if it is studied in the context of other correlated forms of child and adolescent psychopathology using formal models to guide inquiry. Review of both cross-sectional and longitudinal studies of the place of CD in the phenotypic and causal structure of prevalent psychopathology, with an emphasis on similarities and differences between CD and oppositional defiant disorder (ODD). Papers were located using Web of Science by topic searches with no restriction on year of publication. Although some important nosologic questions remain unanswered, the dimensional phenotype of CD is well defined. CD differs from other disorders in its correlates, associated impairment, and course. Nonetheless, it is robustly correlated with many other prevalent dimensions of psychopathology both concurrently and predictively, including both other 'externalizing' disorders and some 'internalizing' disorders. Based on emerging evidence, we hypothesize that these concurrent and predictive correlations result primarily from widespread genetic pleiotropy, with some genetic factors nonspecifically influencing risk for multiple correlated dimensions of psychopathology. In contrast, environmental influences mostly act to differentiate dimensions of psychopathology from one another both concurrently and over time. CD and ODD share half of their genetic influences, but their genetic etiologies are distinct in other ways. Unlike most other dimensions of psychopathology, half of the genetic influences on CD appear to be unique to CD. In contrast, ODD broadly shares nearly all of its genetic influences with other disorders and has little unique genetic variance. Conduct disorder is a relatively distinct syndrome at both phenotypic and etiologic levels, but much is revealed by studying CD in the context of

  16. The comparison of the structures of some cationic forms of clinoptilolite obtained from Manisa-Gordes in Turkey using their XRD spectrums

    International Nuclear Information System (INIS)

    Izci, E.; Orhun, O.

    2000-01-01

    In this study, at room temperature, XRD spectrums of Na, Ca, Li, Pb and natural forms of clinoptilolite, which is a natural zeolite obtained from Manisa-Gordes in Turkey, were taken and compared with each other according to their structures. Firstly, clinoptilolite samples, whose, diameters are smaller than 63 μm, were purified by HCl. Thus, impurities through the channels of clinoptilolite samples, were removed from their structures. Then, the samples washed several times by deionised water and filtered. So, HCl was removed from structures of these samples. Na, Ca, Li, Pb ionic forms of clinoptilolite were prepared by using batch method. XRD apparatus from Rigaku-Rint 2000 series. Comparing of XRD spectrums of these ionic and natural forms of clinoptilolite and finding the variations of their spectrums, what changes in their structures could be, were investigated. (authors)

  17. Ostreolysin A/Pleurotolysin B and Equinatoxins: Structure, Function and Pathophysiological Effects of These Pore-Forming Proteins

    Directory of Open Access Journals (Sweden)

    Robert Frangež

    2017-04-01

    Full Text Available Acidic ostreolysin A/pleurotolysin B (OlyA/PlyB, formerly known as ostreolysin (Oly, and basic 20 kDa equinatoxins (EqTs are cytolytic proteins isolated from the edible mushroom Pleurotus ostreatus and the sea anemone Actinia equina, respectively. Both toxins, although from different sources, share many similar biological activities: (i colloid-osmotic shock by forming pores in cellular and artificial membranes enriched in cholesterol and sphingomyelin; (ii increased vascular endothelial wall permeability in vivo and perivascular oedema; (iii dose-dependent contraction of coronary vessels; (iv haemolysis with pronounced hyperkalaemia in vivo; (v bradycardia, myocardial ischemia and ventricular extrasystoles accompanied by progressive fall of arterial blood pressure and respiratory arrest in rodents. Both types of toxins are haemolytic within nanomolar range concentrations, and it seems that hyperkalaemia plays an important role in toxin cardiotoxicity. However, it was observed that the haemolytically more active EqT III is less toxic than EqT I, the most toxic and least haemolytic EqT. In mice, EqT II is more than 30 times more toxic than OlyA/PlyB when applied intravenously. These observations imply that haemolysis with hyperkalaemia is not the sole cause of the lethal activity of both toxins. Additional mechanisms responsible for lethal action of the two toxins are direct effects on heart, coronary vasoconstriction and related myocardial hypoxia. In this review, we appraise the pathophysiological mechanisms related to the chemical structure of OlyA/PlyB and EqTs, as well as their toxicity.

  18. How much structuring is beneficial with regard to examination scores? A prospective study of three forms of active learning.

    Science.gov (United States)

    Reinhardt, Claus H; Rosen, Evelyne N

    2012-09-01

    Many studies have demonstrated a superiority of active learning forms compared with traditional lecture. However, there is still debate as to what degree structuring is necessary with regard to high exam outcomes. Seventy-five students from a premedical school were randomly attributed to an active lecture group, a cooperative group, or a collaborative learning group. The active lecture group received lectures with questions to resolve at the end of the lecture. At the same time, the cooperative group and the collaborative group had to work on a problem and prepare presentations for their answers. The collaborative group worked in a mostly self-directed manner; the cooperative group had to follow a time schedule. For the additional work of preparing the poster presentation, the collaborative and cooperative groups were allowed 50% more working time. In part 1, all groups worked on the citric acid cycle, and in part 2, all groups worked on molecular genetics. Collaborative groups had to work on tasks and prepare presentations for their answers. At the end of each part, all three groups were subjected to the same exam. Additionally, in the collaborative and cooperative groups, the presentations were marked. All evaluations were performed by two independent examiners. Exam results of the active lecture groups were highest. Results of the cooperative group were nonsignificantly lower than the active lecture group and significantly higher than the collaborative group. The presentation quality was nonsignificantly higher in the collaborative group compared with the cooperative group. This study shows that active lecturing produced the highest exam results, which significantly differed from collaborative learning results. The additional elaboration in the cooperative and collaborative learning setting yielded the high presentation quality but apparently could not contribute further to exam scores. Cooperative learning seems to be a good compromise if high exam and

  19. Chiral nucleon-nucleon forces in nuclear structure calculations

    Directory of Open Access Journals (Sweden)

    Coraggio L.

    2016-01-01

    Full Text Available Realistic nuclear potentials, derived within chiral perturbation theory, are a major breakthrough in modern nuclear structure theory, since they provide a direct link between nuclear physics and its underlying theory, namely the QCD. As a matter of fact, chiral potentials are tailored on the low-energy regime of nuclear structure physics, and chiral perturbation theory provides on the same footing two-nucleon forces as well as many-body ones. This feature fits well with modern advances in ab-initio methods and realistic shell-model. Here, we will review recent nuclear structure calculations, based on realistic chiral potentials, for both finite nuclei and infinite nuclear matter.

  20. Annual Research Review: Phenotypic and Causal Structure of Conduct Disorder in the Broader Context of Prevalent Forms of Psychopathology

    Science.gov (United States)

    Lahey, Benjamin B.; Waldman, Irwin D.

    2012-01-01

    Background: A better understanding of the nature and etiology of conduct disorder (CD) can inform nosology and vice versa. We posit that any prevalent form of psychopathology, including CD, can be best understood if it is studied in the context of other correlated forms of child and adolescent psychopathology using formal models to guide inquiry.…

  1. Emotional Responses to Suicidal Patients: Factor Structure, Construct, and Predictive Validity of the Therapist Response Questionnaire-Suicide Form

    Directory of Open Access Journals (Sweden)

    Shira Barzilay

    2018-04-01

    Full Text Available BackgroundMental health professionals have a pivotal role in suicide prevention. However, they also often have intense emotional responses, or countertransference, during encounters with suicidal patients. Previous studies of the Therapist Response Questionnaire-Suicide Form (TRQ-SF, a brief novel measure aimed at probing a distinct set of suicide-related emotional responses to patients found it to be predictive of near-term suicidal behavior among high suicide-risk inpatients. The purpose of this study was to validate the TRQ-SF in a general outpatient clinic setting.MethodsAdult psychiatric outpatients (N = 346 and their treating mental health professionals (N = 48 completed self-report assessments following their first clinic meeting. Clinician measures included the TRQ-SF, general emotional states and traits, therapeutic alliance, and assessment of patient suicide risk. Patient suicidal outcomes and symptom severity were assessed at intake and one-month follow-up. Following confirmatory factor analysis of the TRQ-SF, factor scores were examined for relationships with clinician and patient measures and suicidal outcomes.ResultsFactor analysis of the TRQ-SF confirmed three dimensions: (1 affiliation, (2 distress, and (3 hope. The three factors also loaded onto a single general factor of negative emotional response toward the patient that demonstrated good internal reliability. The TRQ-SF scores were associated with measures of clinician state anger and anxiety and therapeutic alliance, independently of clinician personality traits after controlling for the state- and patient-specific measures. The total score and three subscales were associated in both concurrent and predictive ways with patient suicidal outcomes, depression severity, and clinicians’ judgment of patient suicide risk, but not with global symptom severity, thus indicating specifically suicide-related responses.ConclusionThe TRQ-SF is a brief and reliable measure with a

  2. Emotional Responses to Suicidal Patients: Factor Structure, Construct, and Predictive Validity of the Therapist Response Questionnaire-Suicide Form.

    Science.gov (United States)

    Barzilay, Shira; Yaseen, Zimri S; Hawes, Mariah; Gorman, Bernard; Altman, Rachel; Foster, Adriana; Apter, Alan; Rosenfield, Paul; Galynker, Igor

    2018-01-01

    Mental health professionals have a pivotal role in suicide prevention. However, they also often have intense emotional responses, or countertransference, during encounters with suicidal patients. Previous studies of the Therapist Response Questionnaire-Suicide Form (TRQ-SF), a brief novel measure aimed at probing a distinct set of suicide-related emotional responses to patients found it to be predictive of near-term suicidal behavior among high suicide-risk inpatients. The purpose of this study was to validate the TRQ-SF in a general outpatient clinic setting. Adult psychiatric outpatients ( N  = 346) and their treating mental health professionals ( N  = 48) completed self-report assessments following their first clinic meeting. Clinician measures included the TRQ-SF, general emotional states and traits, therapeutic alliance, and assessment of patient suicide risk. Patient suicidal outcomes and symptom severity were assessed at intake and one-month follow-up. Following confirmatory factor analysis of the TRQ-SF, factor scores were examined for relationships with clinician and patient measures and suicidal outcomes. Factor analysis of the TRQ-SF confirmed three dimensions: (1) affiliation, (2) distress, and (3) hope. The three factors also loaded onto a single general factor of negative emotional response toward the patient that demonstrated good internal reliability. The TRQ-SF scores were associated with measures of clinician state anger and anxiety and therapeutic alliance, independently of clinician personality traits after controlling for the state- and patient-specific measures. The total score and three subscales were associated in both concurrent and predictive ways with patient suicidal outcomes, depression severity, and clinicians' judgment of patient suicide risk, but not with global symptom severity, thus indicating specifically suicide-related responses. The TRQ-SF is a brief and reliable measure with a 3-factor structure. It demonstrates

  3. The institutions forming the socioeconomic structure of Turkish private enterprises between the 13th and the 19th centuries

    Directory of Open Access Journals (Sweden)

    Mehmet Özbirecikli

    2015-04-01

    principios éticos de la vida empresarial, en esencia, son los mismos. Dentro de este contexto, nos atrevemos a sugerir que las raíces del código ético de la vida empresarial turca se retrotraen en la historia a hace más de 800 años. Además, la similitud entre el funcionamiento presente y pasado indica que el origen de la formación de los aprendices para las empresas turcas tiene, igualmente, más de 800 años de historia.This study investigates three institutions forming the socioeconomic structure of Turkish private enterprises between the 13th and 19th Centuries: Akhism (13th-16th century, the Lonca System (the Guilds (16th-18th century, and the Gedik (Monopoly System (18th-20th century. The study particularly focuses on the social and economic rules, vocational training process, and organizational structure of the said institutions in order to discuss the effects of the socioeconomic structure of Turkish enterprises on economic and social development of private enterprises. The study also struggles to link between the relevant current applications and the applications in the past such as the social rules and vocational training. From economic point of view, both the statist structure of the State and the economic rules of the institutions herein caused private enterprises to remain small, and prevented them from having a competitive environment and having capital accumulation. As a result, enterprises could not benefit from new production techniques and the Turkish enterprise mentality fell behind modern developments On the other hand, although these three systems were completely abolished in the early 20th Century, it is seen that especially traces of the Akhism and Lonca systems have still been surviving. Both the most of rules of Akhism and some of the duties of the board of directors of Lonca such as keeping moral standards of production and trade remind us of professional code of ethics of today's modern business life. In other saying, there was code of

  4. Native aggregation as a cause of origin of temporary cellular structures needed for all forms of cellular activity, signaling and transformations

    Directory of Open Access Journals (Sweden)

    Matveev Vladimir V

    2010-06-01

    Full Text Available Abstract According to the hypothesis explored in this paper, native aggregation is genetically controlled (programmed reversible aggregation that occurs when interacting proteins form new temporary structures through highly specific interactions. It is assumed that Anfinsen's dogma may be extended to protein aggregation: composition and amino acid sequence determine not only the secondary and tertiary structure of single protein, but also the structure of protein aggregates (associates. Cell function is considered as a transition between two states (two states model, the resting state and state of activity (this applies to the cell as a whole and to its individual structures. In the resting state, the key proteins are found in the following inactive forms: natively unfolded and globular. When the cell is activated, secondary structures appear in natively unfolded proteins (including unfolded regions in other proteins, and globular proteins begin to melt and their secondary structures become available for interaction with the secondary structures of other proteins. These temporary secondary structures provide a means for highly specific interactions between proteins. As a result, native aggregation creates temporary structures necessary for cell activity. "One of the principal objects of theoretical research in any department of knowledge is to find the point of view from which the subject appears in its greatest simplicity." Josiah Willard Gibbs (1839-1903

  5. Native aggregation as a cause of origin of temporary cellular structures needed for all forms of cellular activity, signaling and transformations.

    Science.gov (United States)

    Matveev, Vladimir V

    2010-06-09

    According to the hypothesis explored in this paper, native aggregation is genetically controlled (programmed) reversible aggregation that occurs when interacting proteins form new temporary structures through highly specific interactions. It is assumed that Anfinsen's dogma may be extended to protein aggregation: composition and amino acid sequence determine not only the secondary and tertiary structure of single protein, but also the structure of protein aggregates (associates). Cell function is considered as a transition between two states (two states model), the resting state and state of activity (this applies to the cell as a whole and to its individual structures). In the resting state, the key proteins are found in the following inactive forms: natively unfolded and globular. When the cell is activated, secondary structures appear in natively unfolded proteins (including unfolded regions in other proteins), and globular proteins begin to melt and their secondary structures become available for interaction with the secondary structures of other proteins. These temporary secondary structures provide a means for highly specific interactions between proteins. As a result, native aggregation creates temporary structures necessary for cell activity."One of the principal objects of theoretical research in any department of knowledge is to find the point of view from which the subject appears in its greatest simplicity."Josiah Willard Gibbs (1839-1903).

  6. The fundamental structural factor in determining the glass-forming ability and mechanical behavior in the Cu-Zr metallic glasses

    International Nuclear Information System (INIS)

    Sha, Z.D.; Feng, Y.P.; Li, Y.

    2011-01-01

    Research highlights: → A weak but significant hump in trend of the coordinate number and density was observed, respectively. → Our findings indicate our simulation is more accurate to describe the atomic structure of Cu-Zr MGs. The composition-structure-properties correlation was established. → And the effective structural unit for this correlation is the Cu-centered full icosahedra. - Abstract: Using the large-scale atomic/molecular massively parallel simulator, the quantitative composition-structure-properties (including glass-forming ability (GFA) and mechanical behavior) correlations in the Cu-Zr metallic glasses were established. The atomic-level origin of these correlations was tracked down. It was found that the Cu-centered full icosahedron is the microscopic factor that fundamentally influences both GFA and mechanical behavior. Our findings have implications for understanding the nature, forming ability and properties of metallic glasses, and for searching novel metallic glasses with unique functional properties.

  7. Areas and forms of regional cooperation in multi-structured (matreshka-style) regions (Tyumen region, Russia)

    OpenAIRE

    LARIONOV ANDREY V.

    2015-01-01

    The problem of the administrative, economic and social sustainability of a group consisting of neighboring regions with close ties has no clear solution yet. Should closely-tied regions in the long run form a centralized system of administrative bodies, compress their budgets into one, and construct unified social programs, or not? To answer this question, in the article we describe a case that represents the paramount form of cooperation amongst closely-tied regions. It is the case of the so...

  8. Rubber pad forming - Efficient approach for the manufacturing of complex structured sheet metal blanks for food industry

    Science.gov (United States)

    Spoelstra, Paul; Djakow, Eugen; Homberg, Werner

    2017-10-01

    The production of complex organic shapes in sheet metals is gaining more importance in the food industry due to increasing functional and hygienic demands. Hence it is necessary to produce parts with complex geometries promoting cleanability and general sanitation leading to improvement of food safety. In this context, and especially when stainless steel has to be formed into highly complex geometries while maintaining desired surface properties, it is inevitable that alternative manufacturing processes will need to be used which meet these requirements. Rubber pad forming offers high potential when it comes to shaping complex parts with excellent surface quality, with virtually no tool marks and scratches. Especially in cases where only small series are to be produced, rubber pad forming processes offers both technological and economic advantages. Due to the flexible punch, variation in metal thickness can be used with the same forming tool. The investments to set-up Rubber pad forming is low in comparison to conventional sheet metal forming processes. The process facilitates production of shallow sheet metal parts with complex contours and bends. Different bending sequences in a multiple tool set-up can also be conducted. The planned contribution thus describes a brief overview of the rubber pad technology. It shows the prototype rubber pad forming machine which can be used to perform complex part geometries made from stainless steel (1.4301). Based on an analysis of the already existing systems and new machines for rubber pad forming processes, together with their process properties, influencing variables and areas of application, some relevant parts for the food industry are presented.

  9. Crystal Structure, Vibrational Spectroscopy and ab Initio Density Functional Theory Calculations on the Ionic Liquid forming 1,1,3,3-Tetramethylguanidinium bis{(trifluoromethyl)sulfonyl}amide

    DEFF Research Database (Denmark)

    Berg, Rolf W.; Riisager, Anders; Nguyen van Buu, Olivier

    2009-01-01

    The salt 1,1,3,3-tetramethylguanidinium bis{(trifluoromethyl)sulfonyl}amide, [((CH3)(2)N)(2)C=NH2](+)[N(SO2-CF3)(2)](-) or [tmgH][NTf2], easily forms an ionic liquid with high SO2 absorbing capacity. The crystal structure of the salt was determined at 120(2) K by X-ray diffraction. The structure...

  10. An Analysis of Density and Degree-Centrality According to the Social Networking Structure Formed in an Online Learning Environment

    Science.gov (United States)

    Ergün, Esin; Usluel, Yasemin Koçak

    2016-01-01

    In this study, we assessed the communication structure in an educational online learning environment using social network analysis (SNA). The communication structure was examined with respect to time, and instructor's participation. The course was implemented using ELGG, a network learning environment, blended with face-to-face sessions over a…

  11. Structure of the Mature Streptococcal Cysteine Protease Exotoxin mSpeB in Its Active Dimeric Form

    DEFF Research Database (Denmark)

    Olsen, Johan G; Dagil, Robert; Niclasen, Louise Meinert

    2009-01-01

    Invasive infections of Streptococcus pyogenes are dependent on the cysteine protease streptococcal pyrogenic exotoxin B. Previous structures of the enzyme have not disclosed the proper active-site configuration. Here, the crystal structure of the mature enzyme is presented to 1.55 A, disclosing...

  12. PHYSICAL, CHEMICAL, AND STRUCTURAL EVOLUTION OF ZEOLITE-CONTAINING WASTE FORMS PRODUCED FROM METAKAOLINITE AND CALCINED HLW

    International Nuclear Information System (INIS)

    Pareizs, J. M.; Jantzenm, C.M.

    2000-01-01

    Natural and synthetic zeolites are extremely versatile materials. They can adsorb a variety of liquids and gases, and also take part in cation exchange reactions. Zeolites have the ability to sequester ions in lattice positions or within their networks of channels and voids. The zeolites can host alkali, alkaline earth and a variety of higher valance cations. As such they may be a viable alternative for immobilization of low activity waste (LAW) salts and calcines. The process for synthesizing zeolites is well documented for pure starting materials. A reactive aluminosilicate is reacted with an alkaline hydroxide at low temperature (<300 C) to form a zeolite. Processing time and temperature and specific reactants determine the type of zeolite formed. Zeolites are easy to make, and can be synthesized from a wide variety of natural and man made materials. However, relatively little is known about the process if one of the starting materials is a poorly characterized complex mixture of oxides (waste) containing nearly every element in the periodic table. The purpose of this work is to develop a clearer understanding of the advantages and limitations of producing a zeolite waste form from radioactive waste. Dr. M. W. Grutzeck at the Pennsylvania State University is investigating the production of a zeolite waste form using nonradioactive simulants. Dr. C. M. Jantzen and J. M. Pareizs at the Savannah River Technology Center will use the results from simulant work as a starting point for producing a zeolite waste form from an actual Savannah River Site radioactive waste stream

  13. Physical, chemical, and structural evolution of zeolite-containing waste forms produced from metakaolinite and calcined HLW

    International Nuclear Information System (INIS)

    Pareizs, J.M.

    2000-01-01

    Natural and synthetic zeolites are extremely versatile materials. They can adsorb a variety of liquids and gases, and also take part in cation exchange reactions. Zeolites have the ability to sequester ions in lattice positions or within their networks of channels and voids. The zeolites can host alkali, alkaline earth and a variety of higher valence cations. As such they may be a viable alternative for immobilization of low activity waste (LAW) salts and calcines. The process for synthesizing zeolites is well documented for pure starting materials. A reactive aluminosilicate is reacted with an alkaline hydroxide at low temperature to form a zeolite. Processing time and temperature and specific reactants determine the type of zeolite formed. Zeolites are easy to make, and can be synthesized from a wide variety of natural and man made materials. However, relatively little is known about the process if one of the starting materials is a poorly characterized complex mixture of oxides (waste) containing nearly every element in the periodic table. The purpose of this work is to develop a clearer understanding of the advantages and limitations of producing a zeolite waste form from radioactive waste. Dr. M. W. Grutzeck at the Pennsylvania State University is investigating the production of a zeolite waste form using non-radioactive simulants. Dr. C. M. Jantzen and J. M. Pareizs at the Savannah River Technology Center will use the results from simulant work as a starting point for producing a zeolite waste form from an actual Savannah River Site radioactive waste stream

  14. A comparative study on the interaction of phenazinium dyes with low pH induced protonated structure and B-form structure of naturally occurring deoxyribonucleic acid

    International Nuclear Information System (INIS)

    Pradhan, Ankur Bikash; Das, Shubhajit; Haque, Lucy; Bhuiya, Sutanwi; Das, Suman

    2016-01-01

    The interaction of two phenazinium dyes namely Phenosafranine (PSF) and Safranin T (ST) with right-handed B-form and left-handed protonated form of Calf Thymus (CT) DNA was investigated using different spectroscopic techniques. Both the dyes have been shown to bind strongly to the right-handed B-form of DNA by the mechanism intercalation as revealed from fluorescence quenching, circular dichroism (CD) and viscosity measurement. From circular dichroic studies it was evidenced that both of them convert the low pH induced left-handed protonated form of DNA back to the bound right-handed form. Scatchard analysis showed that both the dyes bound strongly to B-form of DNA in a non-cooperative manner. In case of protonated form, there was sequential conversion of the polynucleotide from left-handed to the bound right-handed conformation. Our results suggest that the binding environment of the dyes in the two forms of DNA is similar and our data predict that PSF is more effective in the conversion than ST. Experimental data enabled the calculation of the number of base pairs of protonated-form that adopted a right-handed conformation for each bound dye. Our data revealed that PSF is more effective in the conversion compard to that of ST. These results are attributed to greater steric crowd in ST compared to PSF which restricts the former to intercalate between DNA base pairs. The results of these studies allow a better understanding of dye-polymorphic nucleic acid interactions at a molecular level.

  15. Influence of MgO containing strontium on the structure of ceramic film formed on grain oriented silicon steel surface

    Directory of Open Access Journals (Sweden)

    Daniela C. Leite Vasconcelos

    1999-07-01

    Full Text Available The oxide layer formed on the surface of a grain oriented silicon steel was characterized by SEM and EDS. 3% Si steel substrates were coated by two types of slurries: one formed by MgO and water and other formed by MgO, water and SrSO4. The ceramic films were evaluated by SEM, EDS and X-ray diffraction. Depth profiles of Fe, Si and Mg were obtained by GDS. The magnetic core losses (at 1.7 Tesla, 60 Hz of the coated steel samples were evaluated as well. The use of MgO containing strontium reduced the volume fraction of forsterite particles beneath the outermost ceramic layer. It was observed a reduced magnetic core loss with the use of the slurry with MgO containing strontium.

  16. The Psychometric Properties and Factor Structure of a Welsh Translation of the School Short Form of the Coopersmith Self-Esteem Inventory

    Science.gov (United States)

    Hills, Peter R.; Francis, Leslie J.; Thomas, Enlli

    2007-01-01

    The psychometric properties and factor structure of a Welsh translation of the school short form of the Coopersmith Self-esteem Inventory (SEI-SSF), which is widely used as a measure of children's global self-esteem, was investigated among a sample of 681 pupils attending Welsh-medium primary schools in Wales. It has generally been assumed that…

  17. An assessment of factorial structure and health-related quality of life in problem drug users using the Short Form 36 Health Survey

    NARCIS (Netherlands)

    Buchholz, Angela; Krol, Anneke; Rist, Fred; Nieuwkerk, Pythia T.; Schippers, Gerard M.

    2008-01-01

    AIMS: To confirm the factorial structure of the Short Form 36 Health Survey (SF-36) in problem drug users and to compare their health-related quality of life (HRQOL) with general Dutch population norms. METHOD: Data of 394 participants from the Amsterdam Cohort Study among drug users, who had

  18. Impact of the rate of the additive process of forming a heavy structure deforming in creep on the development of its technological stresses

    Science.gov (United States)

    Parshin, Dmitry A.

    2018-05-01

    The additive process of forming a semicircular arched structure by means of layer-by-layer addition of material to its inner surface is simulated. The impact of this process running mode on the development of the technological stresses fields in the structure being formed under the action of gravity under properties of the material creep and aging is examined. In the framework of the linear mechanics of accreted solids a mathematical model of the process under study is offered and numerical experiments are conducted. It is shown that the stress-strain state of the additively formed heavy objects decisively depends on their formation mode. Various practically important trends and features of this dependence are studied.

  19. Parametric study of self-forming ZnO Nanowall network with honeycomb structure by Pulsed Laser Deposition

    KAUST Repository

    El Zein, B.; Boulfrad, Samir; Jabbour, Ghassan E.; Doghè che, Elhadj Hadj

    2014-01-01

    The successful synthesis of catalyst free zinc oxide (ZnO) Nanowall networks with honeycomb like structure by Pulsed Laser Deposition (PLD) is demonstrated in this paper. The synthesis was conducted directly on Silicon (Si) (1 0 0) and Glass

  20. Towards Prediction Of Crystal Structure Of Al-Rich Intermetallides Formed In Al-T-A Systems

    International Nuclear Information System (INIS)

    Bram, Avraham I.; Meshic, Louisa; Ilse Katz institute for nanotechnology, Ben Gurion University of the Negev; Venkert, Arie

    2014-01-01

    Crystal structure of the material has a significant contribution on its properties. However, there is no universal model that can predict precisely the crystallographic structure of a stable material at specific composition and temperature. Since the 1950's, various prediction approaches were developed and yielded many different methods of computer simulation and innovative theories which are summarized in the review of Woodley et al. These methods are based on complicated calculations of quantum sizes

  1. The effect of concentration on the structure and crystallinity of a cementitious waste form for caustic wastes

    International Nuclear Information System (INIS)

    Chung, Chul-Woo; Turo, Laura A.; Ryan, Joseph V.; Johnson, Bradley R.; McCloy, John S.

    2013-01-01

    Highlights: ► Cast Stone: Portland cement, fly ash, blast furnace slag, and simulated nuclear waste. ► Caustic secondary waste from the off-gas of a vitrification process was targeted. ► Crystallinity, micro- and mesostructure, and engineering properties characterized. ► Waste concentration varied from 0 to 2.5 M, but caused minimal changes. ► Cast Stone shows good compositional versatility as a secondary waste form. -- Abstract: Cement-based waste forms have long been considered economical technologies for disposal of various types of waste. A solidified cementitious waste form, Cast Stone, has been identified to immobilize the radioactive secondary waste from vitrification processes. In this work, Cast Stone was considered for a Na-based caustic liquid waste, and its physical properties were analyzed as a function of liquid waste loading up to 2 M Na. Differences in crystallinity (phase composition), microstructure, mesostructure (pore size distribution and surface area), and macrostructure (density and compressive strength) were investigated using various analytical techniques, in order to assess the suitability of Cast Stone as a chemically durable waste. It was found that the concentration of secondary waste simulant (caustic waste) had little effect on the relevant engineering properties of Cast Stone, showing that Cast Stone could be an effective and tolerant waste form for a wide range of concentrations of high sodium waste

  2. Linking Organisational Training and Development Practices with New Forms of Career Structure: A Cross-National Exploration.

    Science.gov (United States)

    Kelly, Aidan; Brannick, Teresa; Hulpke, John; Levine, Jacqueline; To, Michelle

    2003-01-01

    Human resource management data were collected from 149 Irish, 201 Hong Kong, 92 Singaporean, and 144 Chinese organizations. Career patterns and training practices showed distinct differences. Irish organizations were more likely to have lower levels of career paths; their training practices suggested more new forms of careers. Fewer paths indicate…

  3. Structure-based design of a disulfide-linked oligomeric form of the simian virus 40 (SV40) large T antigen DNA-binding domain

    International Nuclear Information System (INIS)

    Meinke, Gretchen; Phelan, Paul; Fradet-Turcotte, Amélie; Archambault, Jacques; Bullock, Peter A.

    2011-01-01

    With the aim of forming the ‘lock-washer’ conformation of the origin-binding domain of SV40 large T antigen in solution, using structure-based analysis an intermolecular disulfide bridge was engineered into the origin-binding domain to generate higher order oligomers in solution. The 1.7 Å resolution structure shows that the mutant forms a spiral in the crystal and has the de novo disulfide bond at the protein interface, although structural rearrangements at the interface are observed relative to the wild type. The modular multifunctional protein large T antigen (T-ag) from simian virus 40 orchestrates many of the events needed for replication of the viral double-stranded DNA genome. This protein assembles into single and double hexamers on specific DNA sequences located at the origin of replication. This complicated process begins when the origin-binding domain of large T antigen (T-ag ODB) binds the GAGGC sequences in the central region (site II) of the viral origin of replication. While many of the functions of purified T-ag OBD can be studied in isolation, it is primarily monomeric in solution and cannot assemble into hexamers. To overcome this limitation, the possibility of engineering intermolecular disulfide bonds in the origin-binding domain which could oligomerize in solution was investigated. A recent crystal structure of the wild-type T-ag OBD showed that this domain forms a left-handed spiral in the crystal with six subunits per turn. Therefore, we analyzed the protein interface of this structure and identified two residues that could potentially support an intermolecular disulfide bond if changed to cysteines. SDS–PAGE analysis established that the mutant T-ag OBD formed higher oligomeric products in a redox-dependent manner. In addition, the 1.7 Å resolution crystal structure of the engineered disulfide-linked T-ag OBD is reported, which establishes that oligomerization took place in the expected manner

  4. Single-subject structural networks with closed-form rotation invariant matching mprove power in developmental studies of the cortex.

    Science.gov (United States)

    Kandel, Benjamin M; Wang, Danny J J; Gee, James C; Avants, Brian B

    2014-01-01

    Although much attention has recently been focused on single-subject functional networks, using methods such as resting-state functional MRI, methods for constructing single-subject structural networks are in their infancy. Single-subject cortical networks aim to describe the self-similarity across the cortical structure, possibly signifying convergent developmental pathways. Previous methods for constructing single-subject cortical networks have used patch-based correlations and distance metrics based on curvature and thickness. We present here a method for constructing similarity-based cortical structural networks that utilizes a rotation-invariant representation of structure. The resulting graph metrics are closely linked to age and indicate an increasing degree of closeness throughout development in nearly all brain regions, perhaps corresponding to a more regular structure as the brain matures. The derived graph metrics demonstrate a four-fold increase in power for detecting age as compared to cortical thickness. This proof of concept study indicates that the proposed metric may be useful in identifying biologically relevant cortical patterns.

  5. ODMSummary: A Tool for Automatic Structured Comparison of Multiple Medical Forms Based on Semantic Annotation with the Unified Medical Language System.

    Science.gov (United States)

    Storck, Michael; Krumm, Rainer; Dugas, Martin

    2016-01-01

    Medical documentation is applied in various settings including patient care and clinical research. Since procedures of medical documentation are heterogeneous and developed further, secondary use of medical data is complicated. Development of medical forms, merging of data from different sources and meta-analyses of different data sets are currently a predominantly manual process and therefore difficult and cumbersome. Available applications to automate these processes are limited. In particular, tools to compare multiple documentation forms are missing. The objective of this work is to design, implement and evaluate the new system ODMSummary for comparison of multiple forms with a high number of semantically annotated data elements and a high level of usability. System requirements are the capability to summarize and compare a set of forms, enable to estimate the documentation effort, track changes in different versions of forms and find comparable items in different forms. Forms are provided in Operational Data Model format with semantic annotations from the Unified Medical Language System. 12 medical experts were invited to participate in a 3-phase evaluation of the tool regarding usability. ODMSummary (available at https://odmtoolbox.uni-muenster.de/summary/summary.html) provides a structured overview of multiple forms and their documentation fields. This comparison enables medical experts to assess multiple forms or whole datasets for secondary use. System usability was optimized based on expert feedback. The evaluation demonstrates that feedback from domain experts is needed to identify usability issues. In conclusion, this work shows that automatic comparison of multiple forms is feasible and the results are usable for medical experts.

  6. Crystal structure of a human single domain antibody dimer formed through V(H-V(H non-covalent interactions.

    Directory of Open Access Journals (Sweden)

    Toya Nath Baral

    Full Text Available Single-domain antibodies (sdAbs derived from human V(H are considered to be less soluble and prone to aggregate which makes it difficult to determine the crystal structures. In this study, we isolated and characterized two anti-human epidermal growth factor receptor-2 (HER2 sdAbs, Gr3 and Gr6, from a synthetic human V(H phage display library. Size exclusion chromatography and surface plasmon resonance analyses demonstrated that Gr3 is a monomer, but that Gr6 is a strict dimer. To understand this different molecular behavior, we solved the crystal structure of Gr6 to 1.6 Å resolution. The crystal structure revealed that the homodimer assembly of Gr6 closely mimics the V(H-V(L heterodimer of immunoglobulin variable domains and the dimerization interface is dominated by hydrophobic interactions.

  7. Size-dependent structure of CdSe nanoclusters formed after ion implantation in MgO

    International Nuclear Information System (INIS)

    Huis, M.A. van; Veen, A. van; Schut, H.; Eijt, S.W.H.; Kooi, B.J.; Hosson, J.Th.M. de

    2005-01-01

    The band gap as well as the optical and structural properties of semiconductor CdSe nanoclusters change as a function of the nanocluster size. Embedded CdSe nanoclusters in MgO were created by means of sequential Cd and Se ion implantation followed by thermal annealing. Changes during annealing were monitored using optical absorption and positron annihilation spectroscopy. High-resolution TEM on cross-sections after annealing at a temperature of 1300 K showed that clusters with a size below 5 nm have the high-pressure rock-salt structure and are in a cube-on-cube orientation relation with MgO, whereas clusters larger than 5 nm adopt the stable wurtzite crystal structure and were observed in two different orientation relations with MgO

  8. 3D cellular structures and co-cultures formed through the contactless magnetic manipulation of cells on adherent surfaces.

    Science.gov (United States)

    Abdel Fattah, Abdel Rahman; Mishriki, Sarah; Kammann, Tobias; Sahu, Rakesh P; Geng, Fei; Puri, Ishwar K

    2018-02-27

    A magnet array is employed to manipulate diamagnetic cells that are contained in paramagnetic medium to demonstrate for the first time the contactless bioprinting of three-dimensional (3D) cellular structures and co-cultures of breast cancer MCF-7 and endothelial HUVEC at prescribed locations on tissue culture treated well plates. Sequential seeding of different cell lines and the spatial displacement of the magnet array creates co-cultured cellular structures within a well without using physically intrusive well inserts. Both monotypic and co-culture experiments produce morphologically rich 3D cell structures that are otherwise absent in regular monolayer cell cultures. The magnetic contactless bioprinting of cells provides further insight into cell behaviour, invasion strategies and transformations that are useful for potential applications in drug screening, 3D cell culture formation and tissue engineering.

  9. Spherical cauliflower-like carbon dust formed by interaction between deuterium plasma and graphite target and its internal structure

    Energy Technology Data Exchange (ETDEWEB)

    Ohno, N. [Department of Energy Engineering and Science, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan)], E-mail: ohno@ees.nagoya-u.ac.jp; Yoshimi, M. [Department of Energy Engineering and Science, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Tokitani, M. [National Institute for Fusion Science, Oroshi 322-6, Toki 509-5292 (Japan); Takamura, S. [Department of Electronics, Aichi Institute of Technology, Yakusa-cho, Toyota 470-0392 (Japan); Tokunaga, K.; Yoshida, N. [Research Institute for Applied Mechanics, Kyushu University, Kasuga, Fukuoka 816-8580 (Japan)

    2009-06-15

    Simulated experiments to produce carbon dust particles with cauliflower structure have been performed in a liner plasma device, NAGDIS-II by exposing high density deuterium plasma to a graphite sample (IG-430U). Formation of carbon dust depends on the surface temperature and the incident ion energy. At a surface temperature 600-700 K, a lot of isolated spherical dust particles are observed on the graphite target. The internal structure of an isolated dust particle was observed with Focused Ion Beam (FIB) system and Transmission Electron Microscope (TEM) in detail. FIB analysis clearly shows there exist honey-combed cell structure with thin carbon walls in the dust particle and the dust particle grows from the graphite surface. TEM image also shows that the dust particle is made of amorphous carbon with crystallized grains with diameters of 10-50 nm.

  10. Parametric study of self-forming ZnO Nanowall network with honeycomb structure by Pulsed Laser Deposition

    KAUST Repository

    El Zein, B.

    2014-02-01

    The successful synthesis of catalyst free zinc oxide (ZnO) Nanowall networks with honeycomb like structure by Pulsed Laser Deposition (PLD) is demonstrated in this paper. The synthesis was conducted directly on Silicon (Si) (1 0 0) and Glass-ITO substrates without the intermediate of metal catalyst, template or chemical etching. Kinetic of growth and effects of gas pressure and substrate temperature were studied by depositing ZnO films on P type Si (1 0 0) substrates with different deposition parameters. The optimized growth parameters were found as: 10 mTorr oxygen pressure, 600 C substrate temperature, and deposition duration equal or higher than 10 min. X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Photoluminescence (PL) measurements were used to investigate structural, microstructural and optical properties of ZnO Nanowall networks produced. They exhibit a non-uniform size high quality honeycomb structure with low deep level defects. © 2013 Elsevier B.V.

  11. Rapid change with depth in megabenthic structure-forming communities of the Makapu'u deep-sea coral bed

    Science.gov (United States)

    Long, Dustin J.; Baco, Amy R.

    2014-01-01

    Seamounts are largely unexplored undersea mountains rising abruptly from the ocean floor, which can support an increased abundance and diversity of organisms. Deep-sea corals are important benthic structure-formers on current-swept hard substrates in these habitats. While depth is emerging as a factor structuring the fauna of seamounts on a large spatial scale, most work addressing deep-sea coral and seamount community structure has not considered the role of small-scale variation in species distributions. Video from six ROV dives over a depth range of ~320-530 m were analyzed to assess the diversity and density of benthic megafaunal invertebrates across the Makapu'u deep-sea coral bed, offshore of Oahu, Hawaii. At the same time, the physical environment along the dive track was surveyed to relate biotic patterns with abiotic variables including depth, aspect, rugosity, substrate, slope and relief to test the factors structuring community assemblages. Despite the narrow range examined, depth was found to be the strongest structuring gradient, and six unique macrobenthic communities were found, with a 93% faunal dissimilarity over the depth surveyed. Relief, rugosity and slope were also factors in the final model. Alcyonacean octocorals were the dominant macrofaunal invertebrates at all but the deepest depth zone. The commercially harvested precious coral C. secundum was the dominant species at depths 370-470 m, with a distribution that is on average deeper than similar areas. This may be artificial due to the past harvesting of this species on the shallower portion of its range. Primnoid octocorals were the most abundant octocoral family overall. This work yields new insight on the spatial ecology of seamounts, pointing out that community changes can occur over narrow depth ranges and that communities can be structured by small-scale physiography.

  12. Functional characterization and crystal structure of thermostable amylase from Thermotoga petrophila, reveals high thermostability and an unusual form of dimerization

    DEFF Research Database (Denmark)

    Hameed, Uzma; Price, Ian; Ikram-Ul-Haq

    2017-01-01

    and able to hydrolyze starch into dextrin between 90 and 100°C, with optimum activity at 98°C and pH8.5. The activity increased in the presence of Rb(1+), K(1+) and Ca(2+) ions, whereas other ions inhibited activity. The crystal structure of Tp-AmyS at 1.7Å resolution showed common features of the GH-13...... of salivary amylase from a previous crystal structure, and thus could be a functional feature of some amylases....

  13. Numerical study on the thermal and flow characteristics of periodically formed inner wavy structures in a cooling channel

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ju Chul; Park, Sang Hu; Son, Chang Min; Min, June Kee; Ha, Man Yeong [Pusan National University, Busan (Korea, Republic of); Cho, Jong Rae [Korea Maritime University, Busan (Korea, Republic of)

    2015-09-15

    In industrial fields of machine and aerospace, cooling systems consisting of channels are widely used to increase energy efficiency and prevent system overheat. In cooling channels, a reduced pressure drop, an enhanced heat transfer, and a short channel length are considered key design requirements for optimizing the total volume and weight of a system. In this work, we improved heat transfer efficiency by using milli-scale wavy structures inside the channel. By optimizing the inner structures through computational fluid dynamics analysis and Taguchi method, the Nusselt number increased by approximately 11.7% with a similar pressure drop compared with that of a normal channel for a Reynolds number of 1000.

  14. Estimation of Length and Order of Polynomial-based Filter Implemented in the Form of Farrow Structure

    Directory of Open Access Journals (Sweden)

    S. Vukotic

    2016-08-01

    Full Text Available Digital polynomial-based interpolation filters implemented using the Farrow structure are used in Digital Signal Processing (DSP to calculate the signal between its discrete samples. The two basic design parameters for these filters are number of polynomial-segments defining the finite length of impulse response, and order of polynomials in each polynomial segment. The complexity of the implementation structure and the frequency domain performance depend on these two parameters. This contribution presents estimation formulae for length and polynomial order of polynomial-based filters for various types of requirements including attenuation in stopband, width of transitions band, deviation in passband, weighting in passband/stopband.

  15. [The effect of structure of benzimidazoles on the character of forming intramolecular cross-links in DNA and chromatin].

    Science.gov (United States)

    Mil', E M; Zhil'tsova, V M; Biniukov, V I; Zhizhina, G P; Stoliarova, L G; Kuznetsov, Iu P

    1994-01-01

    An investigation of a number of benzimidazole class preparations, being distinguished by a position of aminomethyl substitutes, has been carried out. It has been shown, that the non-substituted preparation BIO-10 does not form UV-cross-links in DNA and chromatine; BIO-40, having one substitute in the position 2, causes the formation of inter-molecular cross-links DNA-DNA. The preparation BIO-50, having 2 aminomethyl groups in the imidazole nucleus positions 2 and 6, forms cross-links DNA-DNA and DNA-protein in chromatine. The generation of radicals by the preparations BIO-10 and BIO-50 has been studied by the EPR-method by use of spin trap. It has been demonstrated, that BIO-10, unlike BIO-50, actively generates superoxide. A supposition has been made, that an UV-formation of superoxide-radical in the presence of BIO-10 might be a reason of DNA-macromolecule destruction.

  16. Flavor structure of the nucleon electromagnetic form factors and transverse charge densities in the chiral quark-soliton model

    Science.gov (United States)

    Silva, António; Urbano, Diana; Kim, Hyun-Chul

    2018-02-01

    We investigate the flavor decomposition of the electromagnetic form factors of the nucleon, based on the chiral quark-soliton model (χQSM) with symmetry-conserving quantization. We consider the rotational 1/N_c and linear strange-quark mass (ms) corrections. We discuss the results of the flavor-decomposed electromagnetic form factors in comparison with the recent experimental data. In order to see the effects of the strange quark, we compare the SU(3) results with those of SU(2). Finally, we discuss the transverse charge densities for both unpolarized and polarized nucleons. The transverse charge density inside a neutron turns out to be negative in the vicinity of the center within the SU(3) χQSM, which can be explained by the contribution of the strange quark.

  17. Emotional Responses to Suicidal Patients: Factor Structure, Construct, and Predictive Validity of the Therapist Response Questionnaire-Suicide Form

    OpenAIRE

    Shira Barzilay; Zimri S. Yaseen; Zimri S. Yaseen; Mariah Hawes; Bernard Gorman; Rachel Altman; Adriana Foster; Alan Apter; Paul Rosenfield; Igor Galynker; Igor Galynker

    2018-01-01

    BackgroundMental health professionals have a pivotal role in suicide prevention. However, they also often have intense emotional responses, or countertransference, during encounters with suicidal patients. Previous studies of the Therapist Response Questionnaire-Suicide Form (TRQ-SF), a brief novel measure aimed at probing a distinct set of suicide-related emotional responses to patients found it to be predictive of near-term suicidal behavior among high suicide-risk inpatients. The purpose o...

  18. A pile-up phenomenon during arsenic diffusion in silicon-on-insulator structures formed by oxygen implantation

    Science.gov (United States)

    Normand, P.; Tsoukalas, D.; Guillemot, N.; Chenevier, P.

    1989-10-01

    Arsenic diffusion in silicon-on-insulator formed by deep oxygen implantation is studied by secondary ion mass spectroscopy and speading resistance measurements. An enhanced diffusivity as well as a pile-up phenomenon are observed in the thin silicon layer. The McNabb and Foster equations [Trans. TMS-AIME 22, 618 (1963)] for diffusion with trapping are solved in order to simulate this last effect.

  19. The Legal Structure of Commercial Banks and Financial Regulation : does organizational form matter for the design of bank regulation?

    OpenAIRE

    Cedeno-Brea, Enmanuel

    2017-01-01

    markdownabstractDo the different ways that commercial banks are legally organized matter for the design of financial regulation? It is often assumed that most commercial banks are setup as investor owned business corporations. However, this is not always the case In many jurisdictions, banks are legally organized using a plethora of organizational forms, which include: co-operatives, mutual associations and even nonprofit entities. Thus, some of the distinctive legal attributes and features o...

  20. Long-term succession of structure and diversity of a biofilm formed in a model drinking water distribution system

    DEFF Research Database (Denmark)

    Martiny, A.C.; Jørgensen, T.M.; Albrechtsen, Hans-Jørgen

    2003-01-01

    from an initial attachment of single cells through the formation of independent microcolonies reaching 30 mum in thickness to a final looser structure with an average thickness of 14.1 mum and covering 76% of the surface. An analysis of the community composition by use of terminal restriction fragment...

  1. The structure formed by inverted repeats in p53 response elements determines the transactivation activity of p53 protein

    Czech Academy of Sciences Publication Activity Database

    Brázda, Václav; Čechová, Jana; Battistin, M.; Coufal, Jan; Jagelská, Eva; Raimondi, I.; Inga, A.

    2017-01-01

    Roč. 483, č. 1 (2017), s. 516-521 ISSN 0006-291X R&D Projects: GA ČR GA15-21855S Institutional support: RVO:68081707 Keywords : tumor-suppressor p53 * cruciform structures * dna-conformation Subject RIV: CE - Biochemistry OBOR OECD: Biochemistry and molecular biology Impact factor: 2.466, year: 2016

  2. Size-dependent structure of CdSe nanoclusters formed after ion implantation in MgO

    NARCIS (Netherlands)

    van Huis, MA; van Veen, A; Schut, H; Eijt, SWH; Kooi, BJ; De Hosson, JTM

    The band gap as well as the optical and structural properties of semiconductor CdSe nanoclusters change as a function of the nanocluster size. Embedded CdSe nanoclusters in MgO were created by means of sequential Cd and Se ion implantation followed by thermal annealing. Changes during annealing were

  3. Structural and dynamic studies of the 12 kDa form of protease from Mason-Pfizer monkey virus

    Czech Academy of Sciences Publication Activity Database

    Veverka, V.; Lang, J.; Bauerová, Helena; Pichová, Iva; Hrabal, R.

    2003-01-01

    Roč. 10, č. 1 (2003), s. 40 ISSN 1211-5894. [Meeting of the Czech and Slovak Structural Biologists /2./. 13.03.2002-15.03.2002, Nové Hrady] R&D Projects: GA ČR GA203/00/1241 Institutional research plan: CEZ:AV0Z4055905 Keywords : M-PMV PR Subject RIV: CE - Biochemistry

  4. Demonstration for the Applicability of the EPRI ETSS on the SG Tube Wear Defects Formed at the Tube Support Structure

    International Nuclear Information System (INIS)

    Shin, Ki Seok; Cheon, Keun Young; Nam, Min Woo; Min, Kyong Mahn

    2013-01-01

    In this paper, the authorized EPRI ETSS 27906.2 applied to the detection of tapered wear volumetric indications and depth sizing within the free span area, loose part not present was reviewed and applied to the site SG tubes for getting the actual value of the wear depth and providing structural integrity interpretation based on engineering evaluation. The experiment to demonstrate the applicability of EPRI ETSS was performed by the employment of the newly prepared STD tube and resulted in ensuring the effectiveness and equivalency of the EPRI ETSS as well. The authorized EPRI ETSS 27906.2 for getting the actual value of the wear depth and providing structural integrity interpretation based on engineering evaluation was reviewed and applied to the site SG tubes. The testing results were reviewed with the influences of SG tube material and the support structure. The impact of the tube materials was insignificant and that of the tube support structure showed somewhat conservative results. The testing resulted in successful demonstration of applicability of the EPRI ETSS on the SG tube wear defects at the tube support. One of the major flaw mechanisms detected in the currently operating domestic OPR-1000 pressurized water reactors(PWR's) steam generator(SG) tubes is wear defect. In general, wear defect has been constantly detected in the upper tube bundle imposed to the flow induced vibration interaction between tube and its support structure, and the quantity of the affected tubes has also shown the tendency to increase as plant operation life is added. In order to take appropriate measures and maintain the structural integrity for the SG tubes, wear defect is currently categorized as active damage mechanism and the tubes containing 40% or greater wear depth of the nominal tube wall thickness shall be plugged per SGMP(SG Management Program) Recently, a fairly large amplitude of wear defects on the Batwing(BW), one of the upper tube support structures in the SG tubes

  5. Demonstration for the Applicability of the EPRI ETSS on the SG Tube Wear Defects Formed at the Tube Support Structure

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Ki Seok; Cheon, Keun Young; Nam, Min Woo [Korea Hydro and Nuclear Power Co. Ltd, Daejeon (Korea, Republic of); Min, Kyong Mahn [Universal Monitoring and Inspection Inc., Daejeon (Korea, Republic of)

    2013-10-15

    In this paper, the authorized EPRI ETSS 27906.2 applied to the detection of tapered wear volumetric indications and depth sizing within the free span area, loose part not present was reviewed and applied to the site SG tubes for getting the actual value of the wear depth and providing structural integrity interpretation based on engineering evaluation. The experiment to demonstrate the applicability of EPRI ETSS was performed by the employment of the newly prepared STD tube and resulted in ensuring the effectiveness and equivalency of the EPRI ETSS as well. The authorized EPRI ETSS 27906.2 for getting the actual value of the wear depth and providing structural integrity interpretation based on engineering evaluation was reviewed and applied to the site SG tubes. The testing results were reviewed with the influences of SG tube material and the support structure. The impact of the tube materials was insignificant and that of the tube support structure showed somewhat conservative results. The testing resulted in successful demonstration of applicability of the EPRI ETSS on the SG tube wear defects at the tube support. One of the major flaw mechanisms detected in the currently operating domestic OPR-1000 pressurized water reactors(PWR's) steam generator(SG) tubes is wear defect. In general, wear defect has been constantly detected in the upper tube bundle imposed to the flow induced vibration interaction between tube and its support structure, and the quantity of the affected tubes has also shown the tendency to increase as plant operation life is added. In order to take appropriate measures and maintain the structural integrity for the SG tubes, wear defect is currently categorized as active damage mechanism and the tubes containing 40% or greater wear depth of the nominal tube wall thickness shall be plugged per SGMP(SG Management Program) Recently, a fairly large amplitude of wear defects on the Batwing(BW), one of the upper tube support structures in the SG

  6. LAYER STRUCTURES FORMED BY SILICA NANOPARTICLES AND CELLULOSE NANOFIBRILS WITH CATIONIC POLYACRYLAMIDE (C-PAM ON CELLULOSE SURFACE AND THEIR INFLUENCE ON INTERACTIONS

    Directory of Open Access Journals (Sweden)

    Jani Salmi

    2009-05-01

    Full Text Available A quartz crystal microbalance with dissipation monitoring (QCM-D was used to study the adsorption of the layer formed by silica nanoparticles (SNP and cellulose nanofibrils (NFC together with cationic polyacrylamide (C-PAM on cellulose surface, accompanied by use of atomic force microscope (AFM to study the interactions between cellulose surfaces. The purpose was to understand the multilayer build-up compared to complex structure adsorption. The layer thickness and consequently also the repulsion between surfaces increased with each addition step during layer formation in the SNP-C-PAM systems, whereas the second addition of C-PAM decreased the repulsion in the case of NFC-C-PAM multilayer formation. An exceptionally high repulsion between surfaces was observed when nanofibrillar cellulose was added. This together with the extremely high dissipation values recorded with QCM-D indicated that nanofibrillar cellulose formed a loose and thick layer containing a lot of water. The multilayer systems formed fully and uniformly covered the surfaces. Silica nanoparticles were able to penetrate inside the loose C-PAM structure due to their small size. In contrast, NFC formed individual layers between C-PAM layers. The complex of C-PAM and SNP formed only a partly covered surface, leading to long-ranged pull-off force. This might explain the good flocculation properties reported for polyelectrolyte-nanoparticle systems.

  7. Influence of university network structures on forming the network environment of regional economy (on the example of national research universities of Tatarstan Republic

    Directory of Open Access Journals (Sweden)

    Darya-Anna Alekseevna Kaibiyainen

    2015-03-01

    Full Text Available Objective to elaborate theoretical and applied aspects of the processes of forming the new network institutional environment of the Russian regional economy under the influence of the developing integral educational network structures basing on the study of the experience of national research universities of Tatarstan Republic Methods general scientific logical methods of analysis and synthesis induction and deduction scientific abstraction as well as the method of systemicfunctional analysis. Results the practical examples are revealed and analyzed of introducing the new network integral principles into the functioning of national research universities which have a real economic effect and influencing such indicators of regional economy as the growth of employment reduction of unemployment etc. Scientific novelty problems of network structures development in the Russian education have not been thoroughly studied yet. The article analyzes the experience reveals and describes the methods and techniques of forming the network educational structures in the functioning of national research universities in Tatarstan Republic Practical value the author shows the ability of network university structures not only to play a significant role forming the new institutional environment of the regional economy but also to influence the macro and microeconomic indicators of development of the region and the country. nbsp

  8. Micro-scale truss structures with three-fold and six-fold symmetry formed from self-propagating polymer waveguides

    Energy Technology Data Exchange (ETDEWEB)

    Jacobsen, Alan J. [HRL Laboratories LLC, Sensors and Materials Laboratory, 3011 Malibu Canyon Road, Malibu, CA 90265-4797 (United States); Department of Aerospace and Mechanical Engineering, University of Southern California, Los Angeles, CA (United States)], E-mail: ajjacobsen@hrl.com; Barvosa-Carter, William [HRL Laboratories LLC, Sensors and Materials Laboratory, 3011 Malibu Canyon Road, Malibu, CA 90265-4797 (United States); Nutt, Steven [Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA (United States)

    2008-06-15

    A process for interconnecting a three-dimensional pattern of self-propagating polymer waveguides was used to form micro-truss structures with two new unit cell architectures. The structures were formed using a two-dimensional mask with a hexagonal pattern of apertures. Distinct unit cell architectures were possible by exposing the mask to a different number of incident UV exposure beams, which are used to form the waveguides. One unit cell design featured three intersecting waveguides per node, resulting in a structure with three-fold symmetry. The second unit cell design had six-fold symmetry and was characterized by primary nodes with six intersecting waveguides and secondary nodes with two intersecting waveguides. Compression loading experiments were conducted on micro-truss samples with comparable relative density values ({rho}/{rho}{sub s} = 6.5%), but different unit cell architectures. The addition of secondary nodes in the structures based on the second design led to an increase in compressive modulus of up to 70% and an average increase in peak strength of 42%. The increase in compressive strength and modulus was attributed to a reduction in the truss-member slenderness ratio achieved through increased waveguide connectivity.

  9. Micro-scale truss structures with three-fold and six-fold symmetry formed from self-propagating polymer waveguides

    International Nuclear Information System (INIS)

    Jacobsen, Alan J.; Barvosa-Carter, William; Nutt, Steven

    2008-01-01

    A process for interconnecting a three-dimensional pattern of self-propagating polymer waveguides was used to form micro-truss structures with two new unit cell architectures. The structures were formed using a two-dimensional mask with a hexagonal pattern of apertures. Distinct unit cell architectures were possible by exposing the mask to a different number of incident UV exposure beams, which are used to form the waveguides. One unit cell design featured three intersecting waveguides per node, resulting in a structure with three-fold symmetry. The second unit cell design had six-fold symmetry and was characterized by primary nodes with six intersecting waveguides and secondary nodes with two intersecting waveguides. Compression loading experiments were conducted on micro-truss samples with comparable relative density values (ρ/ρ s = 6.5%), but different unit cell architectures. The addition of secondary nodes in the structures based on the second design led to an increase in compressive modulus of up to 70% and an average increase in peak strength of 42%. The increase in compressive strength and modulus was attributed to a reduction in the truss-member slenderness ratio achieved through increased waveguide connectivity

  10. Structural relaxation and thermal conductivity of high-pressure formed, high-density di-n-butyl phthalate glass and pressure induced departures from equilibrium state.

    Science.gov (United States)

    Johari, G P; Andersson, Ove

    2017-06-21

    We report a study of structural relaxation of high-density glasses of di-n-butyl phthalate (DBP) by measuring thermal conductivity, κ, under conditions of pressure and temperature (p,T) designed to modify both the vibrational and configurational states of a glass. Various high-density glassy states of DBP were formed by (i) cooling the liquid under a fixed high p and partially depressurizing the glass, (ii) isothermal annealing of the depressurized glass, and (iii) pressurizing the glass formed by cooling the liquid under low p. At a given low p, κ of the glass formed by cooling under high p is higher than that of the glass formed by cooling under low p, and the difference increases as glass formation p is increased. κ of the glass formed under 1 GPa is ∼20% higher at ambient p than κ of the glass formed at ambient p. On heating at low p, κ decreases until the glass to liquid transition range is reached. This is the opposite of the increase in κ observed when a glass formed under a certain p is heated under the same p. At a given high p, κ of the low-density glass formed by cooling at low p is lower than that of the high-density glass formed by cooling at that high p. On heating at high p, κ increases until the glass to liquid transition range is reached. The effects observed are due to a thermally assisted approach toward equilibrium at p different from the glass formation p. In all cases, the density, enthalpy, and entropy would change until the glasses become metastable liquids at a fixed p, thus qualitatively relating κ to variation in these properties.

  11. Physical, Chemical and Structural Evolution of Zeolite-Containing Waste Forms Produced from Metakaolinite and Calcined HLW

    International Nuclear Information System (INIS)

    Grutzeck, Michael; Jantzen, Carol M.

    1999-01-01

    Natural and synthetic zeolites are extremely versatile materials. They can adsorb a variety of liquids and gases, and also take part in cation exchange reactions. Zeolites are easy to synthesize from a wide variety of natural and man made materials. One combination of starting materials that exhibits a great deal of promise is a mixture of metakaolinite and/or Class F fly ash and concentrated sodium hydroxide solution. Once these ingredients are mixed and cured at elevated temperatures, they react to form a hard, dense, ceramic-like material that contains significant amounts of crystalline tectosilicates (zeolites and feldspathoids). Zeolites have the ability to sequester ions in lattice positions or within their networks of channels and voids. As such they are nearly perfect waste forms, the zeolites can host alkali, alkaline earth and a variety of higher valance cations. In addition to zeolites, it has been found that the zeolites are accompanied by an alkali aluminosilicate hydrate matrix that is a host, not only to the zeolites, but to residual amounts of insoluble hydroxide phases as well. A previous publication has established the fact that a mixture of a calcined equivalent ICPP waste (sodium aluminate/hydroxide solution containing ∼3:1 Na:Al) and fly ash and/or metakaolinite could be cured at various temperatures to produce a monolith containing Zeolite A (80 C) or Na-P1 plus hydroxy sodalite (130 C) crystals dispersed in an alkali aluminosilicate hydrate matrix. Dissolution tests have shown these materials (so-called hydroceramics) to have superior retention for alkali, alkaline earth and heavy metal ions. The zeolitization process is a simple one. Metakaolinite and/or Class F fly ash is mixed with a caustic sodium-bearing calcine and enough water to make a thick paste. The paste is transferred to a metal canister and ''soaked'' for a few hours at 70-80 C prior to steam autoclaving the sample at ∼200 C for 6-8 hours. The waste form produced in this

  12. Alternating twist structures formed by electroconvection in the nematic phase of an achiral bent-core molecule.

    Science.gov (United States)

    Tanaka, Shingo; Dhara, Surajit; Sadashiva, B K; Shimbo, Yoshio; Takanishi, Yoichi; Araoka, Fumito; Ishikawa, Ken; Takezoe, Hideo

    2008-04-01

    We report an unusual electroconvection in the nematic phase of a bent-core liquid crystal. In a voltage-frequency diagram, two frequency regions exhibiting prewavy stripe patterns were found, as reported by Wiant We found that these stripes never show extinction dark when cells were rotated under crossed polarizers. Based on the color interchange in between neighboring stripes by the rotation of the cells or an analyzer, twisted molecular orientation is suggested; i.e., the directors are alternately twisted from the top to the bottom surfaces with a pretilt angle in adjacent stripes, which is an analogue of the twisted (splayed) structure observed in surface-stabilized ferroelectric liquid crystal cells. The transmittance spectra calculated using the 4x4 matrix method from the model structure are consistent with the experimental observation.

  13. Electroluminescence properties of Si MOS structures with incorporation of FeSi2 precipitates formed by iron implantation

    International Nuclear Information System (INIS)

    Chow, C.F.; Wong, S.P.; Gao, Y.; Ke, N.; Li, Q.; Cheung, W.Y.; Lourenco, M.A.; Homewood, K.P.

    2005-01-01

    Silicon MOS structures with FeSi 2 precipitates embedded in the MOS active region have been fabricated and the electroluminescence (EL) properties from these FeSi 2 -Si MOS structures were measured as a function of temperature from 80 K to 300 K. Clear EL signals were observed even at room temperature for samples prepared at appropriate processing conditions. The EL spectra consist of two peaks, one attributed to FeSi 2 and the other attributed to Si band edge emission. While the intensity of the FeSi 2 peak showed the usual thermal quenching behavior, the Si band edge emission showed the opposite trend with its intensity increased with increasing temperature. Details of the line shapes and their temperature dependence are analyzed and discussed

  14. Chemical structure, biosynthesis and synthesis of free and glycosylated pyridinolines formed by cross-link of bone and synovium collagen.

    Science.gov (United States)

    Anastasia, Luigi; Rota, Paola; Anastasia, Mario; Allevi, Pietro

    2013-09-21

    This review focuses on the chemical structure, biosynthesis and synthesis of free and glycosylated pyridinolines (Pyds), fluorescent collagen cross-links, with a pyridinium salt structure. Pyds derive from the degradation of bone collagen and have attracted attention for their use as biochemical markers of bone resorption and to assess fracture risk prediction in persons suffering from osteoporosis, bone cancer and other bone or collagen diseases. We consider and critically discuss all reported syntheses of free and glycosylated Pyds evidencing an unrevised chemistry, original and of general utility, analysis of which allows us to also support a previously suggested non-enzymatic formation of Pyds in collagen better rationalizing and justifying the chemical events.

  15. Effect of the Cationic Block Structure on the Characteristics of Sludge Flocs Formed by Charge Neutralization and Patching

    Directory of Open Access Journals (Sweden)

    Huaili Zheng

    2017-05-01

    Full Text Available In this study, a template copolymer (TPAA of (3-Acrylamidopropyl trimethylammonium chloride (AATPAC and acrylamide (AM was successfully synthesized though ultrasonic-initiated template copolymerization (UTP, using sodium polyacrylate (PAAS as a template. TPAA was characterized by an evident cationic microblock structure which was observed through the analyses of the reactivity ratio, Fourier transform infrared spectroscopy (FTIR, 1H (13C nuclear magnetic resonance spectroscopy (1H (13C NMR, and thermogravimetry/differential scanning calorimetry (TG/DSC. The introduction of the template could improve the monomer (AATPAC reactivity ratio and increase the length and amount of AATPAC segments. This novel cationic microblock structure extremely enhanced the ability of charge neutralization, patching, and bridging, thus improving the activated sludge flocculation performance. The experiments of floc formation, breakage, and regrowth revealed that the cationic microblock structure in the copolymer resulted in large and compact flocs, and these flocs had a rapid regrowth when broken. Finally, the larger and more compact flocs contributed to the formation of more channels and voids, and therefore the specific resistance to filtration (SRF reached a minimum.

  16. Atomic force microscopy study of the structure function relationships of the biofilm-forming bacterium Streptococcus mutans

    Science.gov (United States)

    Cross, Sarah E.; Kreth, Jens; Zhu, Lin; Qi, Fengxia; Pelling, Andrew E.; Shi, Wenyuan; Gimzewski, James K.

    2006-02-01

    Atomic force microscopy (AFM) has garnered much interest in recent years for its ability to probe the structure, function and cellular nanomechanics inherent to specific biological cells. In particular, we have used AFM to probe the important structure-function relationships of the bacterium Streptococcus mutans. S. mutans is the primary aetiological agent in human dental caries (tooth decay), and is of medical importance due to the virulence properties of these cells in biofilm initiation and formation, leading to increased tolerance to antibiotics. We have used AFM to characterize the unique surface structures of distinct mutants of S. mutans. These mutations are located in specific genes that encode surface proteins, thus using AFM we have resolved characteristic surface features for mutant strains compared to the wild type. Ultimately, our characterization of surface morphology has shown distinct differences in the local properties displayed by various S. mutans strains on the nanoscale, which is imperative for understanding the collective properties of these cells in biofilm formation.

  17. Experimental and numerical CHT-investigations of cooling structures formed by lost cores in cast housings for optimal heat transfer

    Science.gov (United States)

    Kohlstädt, S.; Vynnycky, M.; Gebauer-Teichmann, A.

    2018-05-01

    This paper investigates the cooling performance of six different lost core designs for automotive cast houses with regard to their cooling efficiency. For this purpose, the conjugate heat transfer (CHT) solver, chtMultiregion, of the freely available CFD-toolbox OpenFOAM in its implementation of version 2.3.1 is used. The turbulence contribution to the Navier-Stokes equations is accounted for by using the RANS Menter SST k - ω model. The results are validated for one of the geometries by comparing with experimental data. Of the six investigated cooling structures, the one that forces the fluid flow to change its direction the most produces the lowest temperatures on the surface of the cast housing. This good cooling performance comes at the price of the highest pressure loss in the cooling fluid and hence increased pump power. It is also found that the relationship between performance and pressure drop is by no means generally linear. Slight changes in the design can lead to a structure which cools almost as well, but at much decreased pressure loss. Regarding the absolute values, the simulations showed that the designed cooling structures are suitable for handling the cooling requirements in the particular applications and that the maximum temperature stays below the critical limits of the electronic components.

  18. Optical properties and oxidation of carbonized and cross-linked structures formed in polycarbonate by plasma immersion ion implantation

    Energy Technology Data Exchange (ETDEWEB)

    Kosobrodova, E., E-mail: elenak@physics.usyd.edu.au [Department of Applied Plasma and Physics, School of Physics, University of Sydney, NSW 2006 (Australia); Kondyurin, A. [Department of Applied Plasma and Physics, School of Physics, University of Sydney, NSW 2006 (Australia); Chrzanowski, W. [Faculty of Pharmacy, University of Sydney, NSW 2006 (Australia); Department of Nanobiomedical Science and BK21 PLUS NBM Global Research, Center for Regenerative Medicine, Dankook University, Cheonan 330-714 (Korea, Republic of); McCulloch, D.G. [School of Applied Sciences, RMIT University, Melbourne, Victoria 3001 (Australia); McKenzie, D.R.; Bilek, M.M.M. [Department of Applied Plasma and Physics, School of Physics, University of Sydney, NSW 2006 (Australia)

    2014-06-01

    Highlights: • Structure and properties of polycarbonate films spin-coated on silicon are studied. • The films have two thicknesses: thicker and thinner than a depth of ion penetration. • Effect of radio frequency plasma and plasma immersion ion implantation is compared. - Abstract: At ion fluences higher than 5 · 10{sup 15} ions/cm{sup 2}, plasma immersion ion implantation (PIII) of polycarbonate (PC) results in a formation of a carbonized surface layer. The thickness of this layer is close to the depth of ion penetration. A comparison of PIII treated, spin-coated PC films with pre-treatment thicknesses designed to match and exceed the carbonized layer thickness is employed to study the properties of the carbonised layer independently from the less modified underlying structure. At ion fluencies higher than 10{sup 16} ions/cm{sup 2}, the thinner PC film is completely transformed into an amorphous carbon-like material with no traces of the initial PC structure. The thicker films, however, incorporated two layers: a top carbonised layer and a cross-linked layer below. Compared to the two-layered PC film, the completely carbonized layer was found to have a much higher concentration of C=O bonds and much lower concentration of O–H bonds after exposure to atmospheric oxygen. The refractive index of the thicker PC films PIII treated with high ion fluencies is close to the refractive index of diamond-like carbon. Anomalous dispersion of the refractive index of the thicker PC films is observed after formation of the carbonised layer. The refractive index of the thinner PC film has normal dispersion at all ion fluences. At ion fluences of 2 · 10{sup 16} ions/cm{sup 2}, both PC films were found to have the same etching rate as polystyrene. Washing in dichloromethane had no effect on the carbonised layer but affected the underlying material in the case of the thicker PC films leading to a wrinkled structure up to ion fluences of 2 · 10{sup 16} ions/cm{sup 2}. At

  19. Quadruplexes in 'Dicty': crystal structure of a four-quartet G-quadruplex formed by G-rich motif found in the Dictyostelium discoideum genome.

    Science.gov (United States)

    Guédin, Aurore; Lin, Linda Yingqi; Armane, Samir; Lacroix, Laurent; Mergny, Jean-Louis; Thore, Stéphane; Yatsunyk, Liliya A

    2018-06-01

    Guanine-rich DNA has the potential to fold into non-canonical G-quadruplex (G4) structures. Analysis of the genome of the social amoeba Dictyostelium discoideum indicates a low number of sequences with G4-forming potential (249-1055). Therefore, D. discoideum is a perfect model organism to investigate the relationship between the presence of G4s and their biological functions. As a first step in this investigation, we crystallized the dGGGGGAGGGGTACAGGGGTACAGGGG sequence from the putative promoter region of two divergent genes in D. discoideum. According to the crystal structure, this sequence folds into a four-quartet intramolecular antiparallel G4 with two lateral and one diagonal loops. The G-quadruplex core is further stabilized by a G-C Watson-Crick base pair and a A-T-A triad and displays high thermal stability (Tm > 90°C at 100 mM KCl). Biophysical characterization of the native sequence and loop mutants suggests that the DNA adopts the same structure in solution and in crystalline form, and that loop interactions are important for the G4 stability but not for its folding. Four-tetrad G4 structures are sparse. Thus, our work advances understanding of the structural diversity of G-quadruplexes and yields coordinates for in silico drug screening programs and G4 predictive tools.

  20. Estimation Of Young’s Modulus Of Elesticity By The Form Finding Of Grid Shell Structures By The Dynamic Relaxation Method

    Directory of Open Access Journals (Sweden)

    Grančičová Ivana

    2015-12-01

    Full Text Available The paper is basically focused on the process of form finding by the dynamic relaxation method (DRM with the aid of computational tools that enable us to make many calculations with different inputs. There are many important input values with a significant impact on the course of the calculations and the resulting displacement of a structure. One of these values is Young’s modulus of elasticity. This value has a considerable impact on the final displacement of a grid shell structure and the resulting internal forces.

  1. Both structural and non-structural forms of the readthrough protein of cucurbit aphid-borne yellows virus are essential for efficient systemic infection of plants.

    Directory of Open Access Journals (Sweden)

    Sylvaine Boissinot

    Full Text Available Cucurbit aphid-borne yellows virus (CABYV is a polerovirus (Luteoviridae family with a capsid composed of the major coat protein and a minor component referred to as the readthrough protein (RT. Two forms of the RT were reported: a full-length protein of 74 kDa detected in infected plants and a truncated form of 55 kDa (RT* incorporated into virions. Both forms were detected in CABYV-infected plants. To clarify the specific roles of each protein in the viral cycle, we generated by deletion a polerovirus mutant able to synthesize only the RT* which is incorporated into the particle. This mutant was unable to move systemically from inoculated leaves inferring that the C-terminal half of the RT is required for efficient long-distance transport of CABYV. Among a collection of CABYV mutants bearing point mutations in the central domain of the RT, we obtained a mutant impaired in the correct processing of the RT which does not produce the RT*. This mutant accumulated very poorly in upper non-inoculated leaves, suggesting that the RT* has a functional role in long-distance movement of CABYV. Taken together, these results infer that both RT proteins are required for an efficient CABYV movement.

  2. Both structural and non-structural forms of the readthrough protein of cucurbit aphid-borne yellows virus are essential for efficient systemic infection of plants.

    Science.gov (United States)

    Boissinot, Sylvaine; Erdinger, Monique; Monsion, Baptiste; Ziegler-Graff, Véronique; Brault, Véronique

    2014-01-01

    Cucurbit aphid-borne yellows virus (CABYV) is a polerovirus (Luteoviridae family) with a capsid composed of the major coat protein and a minor component referred to as the readthrough protein (RT). Two forms of the RT were reported: a full-length protein of 74 kDa detected in infected plants and a truncated form of 55 kDa (RT*) incorporated into virions. Both forms were detected in CABYV-infected plants. To clarify the specific roles of each protein in the viral cycle, we generated by deletion a polerovirus mutant able to synthesize only the RT* which is incorporated into the particle. This mutant was unable to move systemically from inoculated leaves inferring that the C-terminal half of the RT is required for efficient long-distance transport of CABYV. Among a collection of CABYV mutants bearing point mutations in the central domain of the RT, we obtained a mutant impaired in the correct processing of the RT which does not produce the RT*. This mutant accumulated very poorly in upper non-inoculated leaves, suggesting that the RT* has a functional role in long-distance movement of CABYV. Taken together, these results infer that both RT proteins are required for an efficient CABYV movement.

  3. Constant Electric and Magnetic Fields Effect on the Structuring and Thermomechanical and Thermophysical Properties of Nanocomposites Formed from Pectin-Cu(2+)-Polyethyleneimine Interpolyelectrolyte-Metal Complexes.

    Science.gov (United States)

    Demchenko, V; Shtompel', V; Riabov, S; Lysenkov, E

    2015-12-01

    Applying wide-angle X-ray scattering method, thermomechanical analysis, and differential scanning calorimetry, the structural organization and properties of nanocomposites formed by chemical reduction of Сu(2+) cations in the interpolyelectrolyte-metal complex (pectin-Cu(2+)-polyethyleneimine) under the influence of a constant magnetic and electric fields have been studied. It has been found that the chemical reduction of Cu(2+) cations in the interpolyelectrolyte-metal complex bulk under constant electric and magnetic fields leads to formation of nanocomposite consisting of interpolyelectrolyte complex, including pectin-polyethyleneimine and nanoparticles of the metal Cu phase, whereas nanocomposite with Cu/Cu2O nanoparticles is formed in original state (without any field). It was observed that, under constant field, nanocomposites obtained have higher structural glass-transition temperatures and thermal stability.

  4. Micrometer scale guidance of mesenchymal stem cells to form structurally oriented large-scale tissue engineered cartilage.

    Science.gov (United States)

    Chou, Chih-Ling; Rivera, Alexander L; Williams, Valencia; Welter, Jean F; Mansour, Joseph M; Drazba, Judith A; Sakai, Takao; Baskaran, Harihara

    2017-09-15

    Current clinical methods to treat articular cartilage lesions provide temporary relief of the symptoms but fail to permanently restore the damaged tissue. Tissue engineering, using mesenchymal stem cells (MSCs) combined with scaffolds and bioactive factors, is viewed as a promising method for repairing cartilage injuries. However, current tissue engineered constructs display inferior mechanical properties compared to native articular cartilage, which could be attributed to the lack of structural organization of the extracellular matrix (ECM) of these engineered constructs in comparison to the highly oriented structure of articular cartilage ECM. We previously showed that we can guide MSCs undergoing chondrogenesis to align using microscale guidance channels on the surface of a two-dimensional (2-D) collagen scaffold, which resulted in the deposition of aligned ECM within the channels and enhanced mechanical properties of the constructs. In this study, we developed a technique to roll 2-D collagen scaffolds containing MSCs within guidance channels in order to produce a large-scale, three-dimensional (3-D) tissue engineered cartilage constructs with enhanced mechanical properties compared to current constructs. After rolling the MSC-scaffold constructs into a 3-D cylindrical structure, the constructs were cultured for 21days under chondrogenic culture conditions. The microstructure architecture and mechanical properties of the constructs were evaluated using imaging and compressive testing. Histology and immunohistochemistry of the constructs showed extensive glycosaminoglycan (GAG) and collagen type II deposition. Second harmonic generation imaging and Picrosirius red staining indicated alignment of neo-collagen fibers within the guidance channels of the constructs. Mechanical testing indicated that constructs containing the guidance channels displayed enhanced compressive properties compared to control constructs without these channels. In conclusion, using a novel

  5. Morphological Studies on the Triatoma brasiliensis Neiva, 1911 (Hemiptera, Reduviidae, Triatominae Genital Structures and Eggs of Different Chromatic Forms

    Directory of Open Access Journals (Sweden)

    Jane Costa

    1997-07-01

    Full Text Available Triatoma brasiliensis is considered one of the most important Chagas disease vectors being a widespread species in semiarid areas of northeastern Brazil. The species displays distinct chromatic patterns of the cuticle in different localities. Four populations were analyzed in this study: 1-Caicó, Rio Grande do Norte, it will be called the brasiliensis population; 2-Espinosa, Minas Gerais, the melanica population; 3-Petrolina, Pernambuco, the macromelasoma population, and 4-Juazeiro, Bahia, the darker one in overall cuticle coloration, the Juazeiro population. In order to differentiate the four populations of T. brasiliensis, a comparative morphological analysis of external genital structures and of eggs were carried out. The analysis of the male genital structures evidenced minor individual structural variations that did not correlate with chromatic differences or the geographical origins, emphasizing the importance of examining sufficiently large and representative samples before using minor genital variations for taxonomic diagnosis. By scanning electron microscopy of the egg exochorion, each chromatic population presented a distinct ornamentation pattern. The melanica population differed mainly from the other populations studied since it had about 40.6%, 69.6% and 76.6% more perforations, on each cell exochorion, than the brasiliensis, the Juazeiro and the macromelasoma populations respectively. In the melanica population the perforation layout is also peculiar, with densely distributed perforations over all the egg surface. Morphometric measures of the eggs showed statistically significant differences: the macromelasoma population presented the longest length (2.43 mm while the shortest was recorded in the brasiliensis population (2.29 mm.

  6. X-ray structures of the Pseudomonas cichorii D-tagatose 3-epimerase mutant form C66S recognizing deoxy sugars as substrates.

    Science.gov (United States)

    Yoshida, Hiromi; Yoshihara, Akihide; Ishii, Tomohiko; Izumori, Ken; Kamitori, Shigehiro

    2016-12-01

    Pseudomonas cichorii D-tagatose 3-epimerase (PcDTE), which has a broad substrate specificity, efficiently catalyzes the epimerization of not only D-tagatose to D-sorbose but also D-fructose to D-psicose (D-allulose) and also recognizes the deoxy sugars as substrates. In an attempt to elucidate the substrate recognition and catalytic reaction mechanisms of PcDTE for deoxy sugars, the X-ray structures of the PcDTE mutant form with the replacement of Cys66 by Ser (PcDTE_C66S) in complexes with deoxy sugars were determined. These X-ray structures showed that substrate recognition by the enzyme at the 1-, 2-, and 3-positions is responsible for enzymatic activity and that substrate-enzyme interactions at the 4-, 5-, and 6-positions are not essential for the catalytic reaction of the enzyme leading to the broad substrate specificity of PcDTE. They also showed that the epimerization site of 1-deoxy 3-keto D-galactitol is shifted from C3 to C4 and that 1-deoxy sugars may bind to the catalytic site in the inhibitor-binding mode. The hydrophobic groove that acts as an accessible surface for substrate binding is formed through the dimerization of PcDTE. In PcDTE_C66S/deoxy sugar complex structures, bound ligand molecules in both the linear and ring forms were detected in the hydrophobic groove, while bound ligand molecules in the catalytic site were in the linear form. This result suggests that the sugar-ring opening of a substrate may occur in the hydrophobic groove and also that the narrow channel of the passageway to the catalytic site allows a substrate in the linear form to pass through.

  7. Size-dependent structure of CdSe nanoclusters formed after ion implantation in MgO

    OpenAIRE

    van Huis, MA; van Veen, A; Schut, H; Eijt, SWH; Kooi, BJ; De Hosson, JTM

    2005-01-01

    The band gap as well as the optical and structural properties of semiconductor CdSe nanoclusters change as a function of the nanocluster size. Embedded CdSe nanoclusters in MgO were created by means of sequential Cd and Se ion implantation followed by thermal annealing. Changes during annealing were monitored using optical absorption and positron annihilation spectroscopy. High-resolution TEM on cross-sections after annealing at a temperature of 1300 K showed that clusters with a size below 5...

  8. Combining 3D printed forms with textile structures - mechanical and geometrical properties of multi-material systems

    International Nuclear Information System (INIS)

    Sabantina, L; Kinzel, F; Ehrmann, A; Finsterbusch, K

    2015-01-01

    The 3D printing belongs to the rapidly emerging technologies which have the chance to revolutionize the way products are created. In the textile industry, several designers have already presented creations of shoes, dresses or other garments which could not be produced with common techniques. 3D printing, however, is still far away from being a usual process in textile and clothing production. The main challenge results from the insufficient mechanical properties, especially the low tensile strength, of pure 3D printed products, prohibiting them from replacing common technologies such as weaving or knitting. Thus, one way to the application of 3D printed forms in garments is combining them with textile fabrics, the latter ensuring the necessary tensile strength. This article reports about different approaches to combine 3D printed polymers with different textile materials and fabrics, showing chances and limits of this technique. (paper)

  9. A study on structure and tribological properties of the electroerosion coating Mo-Ni-Cu, formed by the mixed method on copper

    Science.gov (United States)

    Romanov, D. A.; Goncharova, E. N.; Gromov, V. E.; Ivanov, Yu F.

    2016-09-01

    Multi-layered coating from immiscible components based on the system Mo-Ni-Cu was formed by the combined method of electro-explosive sputtering and subsequent irradiation by high-intensity pulse electron beam of submillisecond duration of influence on the surface of electrical copper contact (M00 grade of copper). The structure and phase composition studies of the applied coating as well as its mechanical and tribological properties are carried out.

  10. The structure of carbon nanotubes formed of graphene layers L4-8, L5-7, L3-12, L4-6-12

    Science.gov (United States)

    Shapovalova, K. E.; Belenkov, E. A.

    2017-11-01

    We geometrically calculate the optimized structure of nanotubes based on the graphene layers, using the method of molecular mechanics MM+. It was found that only the nanotubes, based on the graphene layers L4-8, L5-7, L3-12, L4-6-12, have a cylindrical form. Calculations of the sublimation energy, carried out using the semi-empirical quantum-mechanic method PM3, show that energy increases with the increase of nanotube diameters.

  11. EFFECT OF THE PHASE STRUCTURE EVOLUTION ON THE PROPERTIES OF FILMS FORMED FROM PBA/P(ST-CO-MMA)COMPOSITE LATEX

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A group of heterogeneous latexes poly(butyl acrylate)/poly(styrene-co-methyl methacrylate)(PBA/P(St-co-MMA))were prepared by a semi-continuous seeded emulsion polymerization process under monomer starved conditions.The glass transition temperature(Tg)and the mechanical properties of the film formed from the composite latex changed with the evolution of the particle morphology.A photon transmission method was used to monitor the phase structure evolution of films which were prepared from core-shell PBA/P(St-co-MMA)latex at room temperature and annealed at 383 K above Tg of the polymers.In addition,the changes of the surface of the film formed from the composite latex with time at 383 K were observed by AFM.The evidence illustrated that the film formed from the core-shell latex particles was metastable.The rearrangement of the phases could occur under proper conditions.

  12. Myroides odoratimimus Forms Structurally Complex and Inherently Antibiotic-Resistant Biofilm in a Wound-Like in vitro Model

    Directory of Open Access Journals (Sweden)

    Arianna Pompilio

    2017-12-01

    Full Text Available Myroides odoratimimus is an aerobic, non-fermenting Gram-negative multidrug-resistant bacterium widely distributed in nature that rarely causes infections in immunocompromised patients. We recently described in a diabetic patient a case of recurrent calcaneal ulcer infection caused by a M. odoratimimus strain showing potential for biofilm formation. For the first time, we therefore evaluated the ability of M. odoratimimus to form biofilm under different pH values and glucose concentrations using an in vitro “skin-like” model, and its susceptibility to levofloxacin, meropenem, and tigecycline. The expression of some antibiotic-resistance related genes was also monitored by RT-PCR during planktonic-to-biofilm transition. Our results indicated that M. odoratimimus can produce relevant amounts of biofilm biomass, in a time-dependent manner, especially at acidic pH and regardless of glucose concentration tested. The comparative analysis of MIC and MBC values between planktonic and sessile cells showed that resistance to antibiotics increased during the planktonic-to-biofilm transition. Viable cell count indicated that none of the tested antibiotics were able to completely eradicate preformed biofilms, although meropenem and levofloxacin were the most active causing a significant, dose-independent, reduction of biofilm's viability, as also confirmed by microscopic analysis. RT-PCR showed that antibiotic-resistance related gyrA and acrB genes are over-expressed during the transition from planktonic to sessile (biofilm lifestyle. Overall, our findings showed that M. odoratimimus can form relevant amounts of inherently antibiotic-resistant biofilm under conditions relevant to wound site, therefore suggesting a role in the pathogenesis of chronic ulcer infections.

  13. Growth and Anatomical Parameters of Adventitious Roots Formed on Mung Bean Hypocotyls Are Correlated with Galactoglucomannan Oligosaccharides Structure

    Directory of Open Access Journals (Sweden)

    K. Kollárová

    2012-01-01

    Full Text Available The effect of galactoglucomannan oligosaccharides (GGMOs compared with chemically modified oligosaccharides, GGMOs-g (with reduced number of D-galactose side chains and GGMOs-r (with reduced reducing ends on mung bean (Vigna radiata (L. Wilczek adventitious roots formation, elongation, and anatomical structure have been studied. All types of oligosaccharides influenced adventitious root formation in the same way: stimulation in the absence of exogenous auxin and inhibition in the presence of exogenous auxin. Both reactions are probably related with the presence/content of endogenous auxin in plant cuttings. However, the adventitious root length was inhibited by GGMOs both in the absence as well as in the presence of auxin (IBA or NAA, while GGMOs-g inhibition was significantly weaker compared with GGMOs. GGMOs-r were without significant difference on both processes, compared with GGMOs. GGMOs affected not only the adventitious root length but also their anatomy in dependence on the combination with certain type of auxin. The oligosaccharides influenced cortical cells division, which was reflected in the cortex area and in the root diameter. All processes followed were dependent on oligosaccharides chemical structure. The results suggest also that GGM-derived oligosaccharides may play an important role in adventitious roots elongation but not in their formation.

  14. Dynamics of water around the complex structures formed between the KH domains of far upstream element binding protein and single-stranded DNA molecules

    Energy Technology Data Exchange (ETDEWEB)

    Chakraborty, Kaushik; Bandyopadhyay, Sanjoy, E-mail: sanjoy@chem.iitkgp.ernet.in [Molecular Modeling Laboratory, Department of Chemistry, Indian Institute of Technology, Kharagpur 721302 (India)

    2015-07-28

    Single-stranded DNA (ss-DNA) binding proteins specifically bind to the single-stranded regions of the DNA and protect it from premature annealing, thereby stabilizing the DNA structure. We have carried out atomistic molecular dynamics simulations of the aqueous solutions of two DNA binding K homology (KH) domains (KH3 and KH4) of the far upstream element binding protein complexed with two short ss-DNA segments. Attempts have been made to explore the influence of the formation of such complex structures on the microscopic dynamics and hydrogen bond properties of the interfacial water molecules. It is found that the water molecules involved in bridging the ss-DNA segments and the protein domains form a highly constrained thin layer with extremely retarded mobility. These water molecules play important roles in freezing the conformational oscillations of the ss-DNA oligomers and thereby forming rigid complex structures. Further, it is demonstrated that the effect of complexation on the slow long-time relaxations of hydrogen bonds at the interface is correlated with hindered motions of the surrounding water molecules. Importantly, it is observed that the highly restricted motions of the water molecules bridging the protein and the DNA components in the complexed forms originate from more frequent hydrogen bond reformations.

  15. On the role of individualized Regge poles in forming refractive structures in light and heavy ion scattering at large angles

    International Nuclear Information System (INIS)

    Kuznichenko, A.V.; Onyshchenko, G.M.; Pilipenko, V.V.; Burtebaev, N.; Zhurunbayeva, G.S.

    2002-01-01

    Investigation of the refraction structures in cross sections of nuclear scattering is a well-known method of probing the interior parts of the interaction region of colliding nuclei and attracts much attention. During recent years essential success was achieved in the experimental studies of scattering of light and heavy ions in wide scattering angle range. The studies were carried out not only in the energy region with standard nuclear rainbow behavior but also at energies near and below the critical energy of nuclear rainbow E cr which revealed well pronounced refractive structures in the angular distributions of the processes studied including rainbow-like maximums and anomalous large angle scattering. To analyze evolution of the refraction effects with energy a new S-matrix model, which can supplement the results of the analyses on the basis of commonly used optical potential approach. The S-matrix model takes into account of some Regge poles near the real axis ('individualized' poles), which addresses the case of energies near and below E cr . Basing on developed model a number a scattering patterns for system α+A, 16 O+ 16 O and 16 O+ 12 C at different energy values have been analyzed. The comparison with results of optical model analyses have been made. The studies were complemented by the analysis on basis of the modified Fuller procedure of decomposition of cross sections into near and far components with removing unphysical contributions. The results of analysis performed suggest the conclusion that the observed refractive structures at large angles (both the rainbow-like ones and ALAS) at E≤E cr are strongly affected by the above mentioned individualized Regge poles. Strictly saying, the scattering in this energy region is not a pure rainbow one, but is of transition character. The arising Regge poles can be considered as a quantum analog for the transition to the orbiting regime in the case of classical scattering. The notch test of the sensitivity

  16. Structural Disorder within Paramyxoviral Nucleoproteins and Phosphoproteins in Their Free and Bound Forms: From Predictions to Experimental Assessment

    Directory of Open Access Journals (Sweden)

    Johnny Habchi

    2015-07-01

    Full Text Available We herein review available computational and experimental data pointing to the abundance of structural disorder within the nucleoprotein (N and phosphoprotein (P from three paramyxoviruses, namely the measles (MeV, Nipah (NiV and Hendra (HeV viruses. We provide a detailed molecular description of the mechanisms governing the disorder-to-order transition that the intrinsically disordered C-terminal domain (NTAIL of their N proteins undergoes upon binding to the C-terminal X domain (PXD of the homologous P proteins. We also show that NTAIL–PXD complexes are “fuzzy”, i.e., they possess a significant residual disorder, and discuss the possible functional significance of this fuzziness. Finally, we emphasize the relevance of N–P interactions involving intrinsically disordered proteins as promising targets for new antiviral approaches, and end up summarizing the general functional advantages of disorder for viruses.

  17. Microbial Community Structure and Arsenic Biogeochemistry in an Acid Vapor-Formed Spring in Tengchong Geothermal Area, China.

    Directory of Open Access Journals (Sweden)

    Zhou Jiang

    Full Text Available Arsenic biogeochemistry has been studied extensively in acid sulfate-chloride hot springs, but not in acid sulfate hot springs with low chloride. In this study, Zhenzhuquan in Tengchong geothermal area, a representative acid sulfate hot spring with low chloride, was chosen to study arsenic geochemistry and microbial community structure using Illumina MiSeq sequencing. Over 0.3 million 16S rRNA sequence reads were obtained from 6-paired parallel water and sediment samples along its outflow channel. Arsenic oxidation occurred in the Zhenxhuquan pool, with distinctly high ratios of arsenate to total dissolved arsenic (0.73-0.86. Coupled with iron and sulfur oxidation along the outflow channel, arsenic accumulated in downstream sediments with concentrations up to 16.44 g/kg and appeared to significantly constrain their microbial community diversity. These oxidations might be correlated with the appearance of some putative functional microbial populations, such as Aquificae and Pseudomonas (arsenic oxidation, Sulfolobus (sulfur and iron oxidation, Metallosphaera and Acidicaldus (iron oxidation. Temperature, total organic carbon and dissolved oxygen significantly shaped the microbial community structure of upstream and downstream samples. In the upstream outflow channel region, most microbial populations were microaerophilic/anaerobic thermophiles and hyperthermophiles, such as Sulfolobus, Nocardia, Fervidicoccus, Delftia, and Ralstonia. In the downstream region, aerobic heterotrophic mesophiles and thermophiles were identified, including Ktedonobacteria, Acidicaldus, Chthonomonas and Sphingobacteria. A total of 72.41-95.91% unassigned-genus sequences were derived from the downstream high arsenic sediments 16S rRNA clone libraries. This study could enable us to achieve an integrated understanding on arsenic biogeochemistry in acid hot springs.

  18. Microbial Community Structure and Arsenic Biogeochemistry in an Acid Vapor-Formed Spring in Tengchong Geothermal Area, China.

    Science.gov (United States)

    Jiang, Zhou; Li, Ping; Jiang, Dawei; Dai, Xinyue; Zhang, Rui; Wang, Yanhong; Wang, Yanxin

    2016-01-01

    Arsenic biogeochemistry has been studied extensively in acid sulfate-chloride hot springs, but not in acid sulfate hot springs with low chloride. In this study, Zhenzhuquan in Tengchong geothermal area, a representative acid sulfate hot spring with low chloride, was chosen to study arsenic geochemistry and microbial community structure using Illumina MiSeq sequencing. Over 0.3 million 16S rRNA sequence reads were obtained from 6-paired parallel water and sediment samples along its outflow channel. Arsenic oxidation occurred in the Zhenxhuquan pool, with distinctly high ratios of arsenate to total dissolved arsenic (0.73-0.86). Coupled with iron and sulfur oxidation along the outflow channel, arsenic accumulated in downstream sediments with concentrations up to 16.44 g/kg and appeared to significantly constrain their microbial community diversity. These oxidations might be correlated with the appearance of some putative functional microbial populations, such as Aquificae and Pseudomonas (arsenic oxidation), Sulfolobus (sulfur and iron oxidation), Metallosphaera and Acidicaldus (iron oxidation). Temperature, total organic carbon and dissolved oxygen significantly shaped the microbial community structure of upstream and downstream samples. In the upstream outflow channel region, most microbial populations were microaerophilic/anaerobic thermophiles and hyperthermophiles, such as Sulfolobus, Nocardia, Fervidicoccus, Delftia, and Ralstonia. In the downstream region, aerobic heterotrophic mesophiles and thermophiles were identified, including Ktedonobacteria, Acidicaldus, Chthonomonas and Sphingobacteria. A total of 72.41-95.91% unassigned-genus sequences were derived from the downstream high arsenic sediments 16S rRNA clone libraries. This study could enable us to achieve an integrated understanding on arsenic biogeochemistry in acid hot springs.

  19. The Logical Structures of Comparison: Its Forms, Styles, Problems, and the Role of History in Social and Political Research

    Directory of Open Access Journals (Sweden)

    Fabio de Nardis

    2014-11-01

    Full Text Available All political sciences share the same logic and methods as the empirical social sciences and therefore produce perceptive knowledge. Empirical knowledge is based on a specific kind of observation driven by a set of theoretically developed concepts related to clearly observable social phenomena. Not all the concepts, however, are readily amenable to observational terms. We usually need to proceed to their operationalization. The formulation and the operational definition of the empirical concepts does not exhaust the analytic process. It is also necessary to observe how the phenomenon occurs in the reality, proceeding to classification or typological constructions and, sometimes, to the production of multi-dimensional models. Only after this process will the formulation of hypotheses be possible. They will later be verified through the use of methods of empirical control. The most frequently used activity in political sociology is comparison, which is the main method of any social science according to most scholars. Comparison can be carried out both among a certain number of cases or within a single case by comparing it in its historical development. The temporal dimension becomes crucial when one wishes to produce historically rooted generalizations and theories, therefore confined to a spatial and temporal dimension. Before proceeding with the comparison we must make sure that the cases selected are actually comparable and that they possess at least one property in common. The objective of this paper is therefore to describe forms and styles of comparison within the logic of social and political sciences

  20. Structural and Morphological Difference Between Ti/TiN/TiCN Coatings Grown in Multilayer and Graded Form

    International Nuclear Information System (INIS)

    Restrepo, E.; Baena, A.; Agudelo, C.; Castillo, H.; Devia, A.; Marino, A.

    2006-01-01

    Thin films can be grown in super-lattice, multilayers and graded form, having each one advantages and disadvantages. The difference between multilayer and graded coatings is the interface. In multilayers the interface is abrupt and in graded coatings it is diffuse. The interface influences many chemical and physical properties of the materials, and its choice depends on the application. Graded coatings have the advantage of having gradual properties such as thermal expansion coefficient and lattice parameter, avoiding adherence problems due to good match between their component materials. In this work the comparison between some properties of coatings grown as multilayer and graded is performed. The materials are produced using the sputtering DC technique because of its facility to control the deposition parameters and generate a slow growth. The target is a disc of titanium and the samples are made of stainless steel 304. The working gases are argon, nitrogen and methane, which are mixed according to the material to be produced, i.e. Ti layer is grown with argon, the TiN film is produced with a mixture of argon and nitrogen, and the TiCN material is obtained mixing argon, nitrogen and methane. These materials are characterized with AFM in order to determine grain size and with XPS studying the chemical composition and performing depth profiles

  1. Three-dimensional structure of phosphopantetheine adenylyltransferase from Mycobacterium tuberculosis in the apo form and in complexes with coenzyme A and dephosphocoenzyme A

    International Nuclear Information System (INIS)

    Timofeev, V. I.; Smirnova, E. A.; Chupova, L. A.; Esipov, R. S.; Kuranova, I. P.

    2012-01-01

    Crystals of phosphopantetheine adenylyltransferase (PPAT) from Mycobacterium tuberculosis in the apo form and in complexes with coenzyme A (PPAT/CoA) and dephosphocoenzyme A (PPAT/dPCoA) were grown in microgravity by the capillary counter-diffusion method. The structures of PPAT Mt in the apo form and in complexes with ligands were solved based on the X-ray diffraction data collected from the grown crystals. The crystal structures were refined at 1.76, 1.59, and 1.59 Å resolution to Rf factors of 0.175, 0.159, and 0.157 and Rfree of 0.224, 0.208, and 0.206 for PPAT, PPAT/CoA, and PPAT/dPCoA, respectively. The atomic coordinates of the structures were deposited in the Protein Data Bank (PDB ID: 3RFF, 3RHS, and 3RBA). In these structures, the ligand-binding sites were determined, the environment of these sites was characterized, and the conformational changes accompanying the ligand binding were analyzed.

  2. 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.

  3. Crystal structure of the complex of carboxypeptidase A with a strongly bound phosphonate in a new crystalline form: comparison with structures of other complexes.

    Science.gov (United States)

    Kim, H; Lipscomb, W N

    1990-06-12

    O-[[(1R)-[[N-(Phenylmethoxycarbonyl)-L-alanyl]amino]ethyl] hydroxyphosphinyl]-L-3-phenyllacetate [ZAAP(O)F], an analogue of (benzyloxycarbonyl)-Ala-Ala-Phe or (benzyloxycarbonyl)-Ala-Ala-phenyllactate, binds to carboxypeptidase A with great affinity (Ki = 3 pM). Similar phosphonates have been shown to be transition-state analogues of the CPA-catalyzed hydrolysis [Hanson, J. E., Kaplan, A. P., & Bartlett, P. A. (1989) Biochemistry 28, 6294-6305]. In the present study, the structure of the complex of this phosphonate with carboxypeptidase A has been determined by X-ray crystallography to a resolution of 2.0 A. The complex crystallizes in the space group P2(1)2(1)2(1) with cell dimensions a = 61.9 A, b = 67.2 A, and c = 76.2 A. The structure of the complex was solved by molecular replacement. Refinement of the structure against 20,776 unique reflections between 10.0 and 2.0 A yields a crystallographic residual of 0.193, including 140 water molecules. The two phosphinyl oxygens of the inhibitor bind to the active-site zinc at 2.2 A on the electrophilic (Arg-127) side and 3.1 A on the nucleophilic (Glu-270) side. Various features of the binding mode of this phosphonate inhibitor are consistent with the hypothesis that carboxypeptidase A catalyzed hydrolysis proceeds through a general-base mechanism in which the carbonyl carbon of the substrate is attacked by Zn-hydroxyl (or Zn-water). An unexpected feature of the bound inhibitor, the cis carbamoyl ester bond at the benzyloxycarbonyl linkage to alanine, allows the benzyloxycarbonyl phenyl ring of the inhibitor to interact favorably with Tyr-198. This complex structure is compared with previous structures of carboxypeptidase A, including the complexes with the potato inhibitor, a hydrated keto methylene substrate analogue, and a phosphonamidate inhibitor. Comparisons are also made with the complexes of thermolysin with some phosphonamidate inhibitors.

  4. Full-scale experimental and numerical study about structural behaviour of a thin-walled cold-formed steel building affected by ground settlements due to land subsidence

    Directory of Open Access Journals (Sweden)

    J. A. Ortiz

    2015-11-01

    Full Text Available Land subsidence due to ground water withdrawal is a problem in many places around the world (Poland, 1984. This causes differential ground settlements that affect masonry structures, because these structural materials do not exhibit an adequate performance beyond a certain level of angular distortion. This work presents the experimental and numerical results about a study regarding the performance of a full-scale thin-walled cold-formed steel building affected by ground differential settlements due to land subsidence. The experimental stage consisted in the construction of a test-building to be subjected to differential settlements in laboratory. The numerical stage consisted in performing a numerical non-linear static pull-down analysis simulating the differential ground settlements of the test-building. The results show that the structural performance of the tested building was very suitable in terms of ductility.

  5. Pushing the size limit of de novo structure ensemble prediction guided by sparse SDSL-EPR restraints to 200 residues: The monomeric and homodimeric forms of BAX

    Science.gov (United States)

    Fischer, Axel W.; Bordignon, Enrica; Bleicken, Stephanie; García-Sáez, Ana J.; Jeschke, Gunnar; Meiler, Jens

    2016-01-01

    Structure determination remains a challenge for many biologically important proteins. In particular, proteins that adopt multiple conformations often evade crystallization in all biologically relevant states. Although computational de novo protein folding approaches often sample biologically relevant conformations, the selection of the most accurate model for different functional states remains a formidable challenge, in particular, for proteins with more than about 150 residues. Electron paramagnetic resonance (EPR) spectroscopy can obtain limited structural information for proteins in well-defined biological states and thereby assist in selecting biologically relevant conformations. The present study demonstrates that de novo folding methods are able to accurately sample the folds of 192-residue long soluble monomeric Bcl-2-associated X protein (BAX). The tertiary structures of the monomeric and homodimeric forms of BAX were predicted using the primary structure as well as 25 and 11 EPR distance restraints, respectively. The predicted models were subsequently compared to respective NMR/X-ray structures of BAX. EPR restraints improve the protein-size normalized root-mean-square-deviation (RMSD100) of the most accurate models with respect to the NMR/crystal structure from 5.9 Å to 3.9 Å and from 5.7 Å to 3.3 Å, respectively. Additionally, the model discrimination is improved, which is demonstrated by an improvement of the enrichment from 5% to 15% and from 13% to 21%, respectively. PMID:27129417

  6. Characterization of dimethacrylate polymeric networks: a study of the crosslinked structure formed by monomers used in dental composites.

    Science.gov (United States)

    Pfeifer, Carmem S; Shelton, Zachary R; Braga, Roberto R; Windmoller, Dario; Machado, José C; Stansbury, Jeffrey W

    2011-02-01

    The resin phase of dental composites is mainly composed of combinations of dimethacrylate comonomers, with final polymeric network structure defined by monomer type/reactivity and degree of conversion. This fundamental study evaluates how increasing concentrations of the flexible triethylene glycol dimethacrylate (TEGDMA) influences void formation in bisphenol A diglycidyl dimethacrylate (BisGMA) co-polymerizations and correlates this aspect of network structure with reaction kinetic parameters and macroscopic volumetric shrinkage. Photopolymerization kinetics was followed in real-time by a near-infrared (NIR) spectroscopic technique, viscosity was assessed with a viscometer, volumetric shrinkage was followed with a linometer, free volume formation was determined by positron annihilation lifetime spectroscopy (PALS) and the sol-gel composition was determined by extraction with dichloromethane followed by (1)H-NMR analysis. Results show that, as expected, volumetric shrinkage increases with TEGDMA concentration and monomer conversion. Extraction/(1)H-NMR studies show increasing participation of the more flexible TEGDMA towards the limiting stages of conversion/crosslinking development. As the conversion progresses, either based on longer irradiation times or greater TEGDMA concentrations, the network becomes more dense, which is evidenced by the decrease in free volume and weight loss after extraction in these situations. For the same composition (BisGMA/TEGDMA 60-40 mol%) light-cured for increasing periods of time (from 10 to 600 s), free volume decreased and volumetric shrinkage increased, in a linear relationship with conversion. However, the correlation between free volume and macroscopic volumetric shrinkage was shown to be rather complex for variable compositions exposed for the same time (600 s). The addition of TEGDMA decreases free-volume up to 40 mol% (due to increased conversion), but above that concentration, in spite of the increase in conversion

  7. Textured surface structures formed using new techniques on transparent conducting Al-doped zinc oxide films prepared by magnetron sputtering

    International Nuclear Information System (INIS)

    Minami, Tadatsugu; Miyata, Toshihiro; Uozaki, Ryousuke; Sai, Hitoshi; Koida, Takashi

    2016-01-01

    Surface-textured Al-doped ZnO (AZO) films formed using two new techniques based on magnetron sputtering deposition were developed by optimizing the light scattering properties to be suitable for transparent electrode applications in thin-film silicon solar cells. Scrambled egg-like surface-textured AZO films were prepared using a new texture formation technique that post-etched pyramidal surface-textured AZO films prepared under deposition conditions suppressing c-axis orientation. In addition, double surface-textured AZO films were prepared using another new texture formation technique that completely removed, by post-etching, the pyramidal surface-textured AZO films previously prepared onto the initially deposited low resistivity AZO films; simultaneously, the surface of the low resistivity films was slightly etched. However, the obtained very high haze value in the range from the near ultraviolet to visible light in the scrambled egg-like surface-textured AZO films did not contribute significantly to the obtainable photovoltaic properties in the solar cells fabricated using the films. Significant light scattering properties as well as a low sheet resistance could be achieved in the double surface-textured AZO films. In addition, a significant improvement of external quantum efficiency in the range from the near ultraviolet to visible light was achieved in superstrate-type n-i-p μc-Si:H solar cells fabricated using a double surface-textured AZO film prepared under optimized conditions as the transparent electrode. - Highlights: • Double surface-textured AZO films prepared using a new texture formation technique • Extensive light scattering properties with low sheet resistance achieved in the double surface-textured AZO films • Improved external quantum efficiency of μc-Si:H solar cells using a double surface-textured AZO film

  8. Textured surface structures formed using new techniques on transparent conducting Al-doped zinc oxide films prepared by magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Minami, Tadatsugu [Optoelectronic Device System R& D Center, Kanazawa Institute of Technology, Nonoichi, Ishikawa 921-8501 (Japan); Miyata, Toshihiro, E-mail: tmiyata@neptune.kanazawa-it.ac.jp [Optoelectronic Device System R& D Center, Kanazawa Institute of Technology, Nonoichi, Ishikawa 921-8501 (Japan); Uozaki, Ryousuke [Optoelectronic Device System R& D Center, Kanazawa Institute of Technology, Nonoichi, Ishikawa 921-8501 (Japan); Sai, Hitoshi; Koida, Takashi [Research Center for Photovoltaics, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568 (Japan)

    2016-09-01

    Surface-textured Al-doped ZnO (AZO) films formed using two new techniques based on magnetron sputtering deposition were developed by optimizing the light scattering properties to be suitable for transparent electrode applications in thin-film silicon solar cells. Scrambled egg-like surface-textured AZO films were prepared using a new texture formation technique that post-etched pyramidal surface-textured AZO films prepared under deposition conditions suppressing c-axis orientation. In addition, double surface-textured AZO films were prepared using another new texture formation technique that completely removed, by post-etching, the pyramidal surface-textured AZO films previously prepared onto the initially deposited low resistivity AZO films; simultaneously, the surface of the low resistivity films was slightly etched. However, the obtained very high haze value in the range from the near ultraviolet to visible light in the scrambled egg-like surface-textured AZO films did not contribute significantly to the obtainable photovoltaic properties in the solar cells fabricated using the films. Significant light scattering properties as well as a low sheet resistance could be achieved in the double surface-textured AZO films. In addition, a significant improvement of external quantum efficiency in the range from the near ultraviolet to visible light was achieved in superstrate-type n-i-p μc-Si:H solar cells fabricated using a double surface-textured AZO film prepared under optimized conditions as the transparent electrode. - Highlights: • Double surface-textured AZO films prepared using a new texture formation technique • Extensive light scattering properties with low sheet resistance achieved in the double surface-textured AZO films • Improved external quantum efficiency of μc-Si:H solar cells using a double surface-textured AZO film.

  9. Structural, thermal, morphological and biological studies of proton-transfer complexes formed from 4-aminoantipyrine with quinol and picric acid

    Science.gov (United States)

    Adam, Abdel Majid A.

    2013-03-01

    4-Aminoantipyrine (4AAP) is widely used in the pharmaceutical industry, biochemical experiments and environmental monitoring. However, residual amounts of 4AAP in the environment may pose a threat to human health. To provide basic data that can be used to extract or eliminate 4AAP from the environment, the proton-transfer complexes of 4AAP with quinol (QL) and picric acid (PA) were synthesized and spectroscopically investigated. The interactions afforded two new proton-transfer salts named 1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-aminium-4-hydroxyphenolate and 1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-aminium-2,4,6-trinitrophenolate for QL and PA, respectively, via a 1:1 stoichiometry. Elemental analysis (CHN), electronic absorption, spectrophotometric titration, IR, Raman, 1H NMR and X-ray diffraction were used to characterize the new products. The thermal stability of the synthesized CT complexes was investigated using thermogravimetric (TG) analyses, and the morphology and particle size of these complexes were obtained from scanning electron microscopy (SEM). It was found that PA and 4AAP immediately formed a yellow precipitate with a remarkable sponge-like morphology and good thermal stability up to 180 °C. Finally, the biological activities of the newly synthesized CT complexes were tested for their antibacterial and antifungal activities. The results indicated that the [(4AAP)(QL)] complex exhibited strong antimicrobial activities against various bacterial and fungal strains compared with standard drugs.

  10. Crystal Structure of a Monomeric Form of Severe Acute Respiratory Syndrome Coronavirus Endonuclease Nsp15 Suggests a Role for Hexamerization As An Allosteric Switch

    Energy Technology Data Exchange (ETDEWEB)

    Joseph, J.S.; Saikatendu, K.S.; Subramanian, V.; Neuman, B.W.; Buchmeier, M.J.; Stevens, R.C.; Kuhn, P.; /Scripps Res. Inst.

    2007-07-09

    Mature nonstructural protein-15 (nsp15) from the severe acute respiratory syndrome coronavirus (SARS-CoV) contains a novel uridylate-specific Mn{sup 2+}-dependent endoribonuclease (NendoU). Structure studies of the full-length form of the obligate hexameric enzyme from two CoVs, SARS-CoV and murine hepatitis virus, and its monomeric homologue, XendoU from Xenopus laevis, combined with mutagenesis studies have implicated several residues in enzymatic activity and the N-terminal domain as the major determinant of hexamerization. However, the tight link between hexamerization and enzyme activity in NendoUs has remained an enigma. Here, we report the structure of a trimmed, monomeric form of SARS-CoV nsp15 (residues 28 to 335) determined to a resolution of 2.9 Angstroms. The catalytic loop (residues 234 to 249) with its two reactive histidines (His 234 and His 249) is dramatically flipped by {approx}120 degrees into the active site cleft. Furthermore, the catalytic nucleophile Lys 289 points in a diametrically opposite direction, a consequence of an outward displacement of the supporting loop (residues 276 to 295). In the full-length hexameric forms, these two loops are packed against each other and are stabilized by intimate intersubunit interactions. Our results support the hypothesis that absence of an adjacent monomer due to deletion of the hexamerization domain is the most likely cause for disruption of the active site, offering a structural basis for why only the hexameric form of this enzyme is active.

  11. Structure-forming corals and sponges and their use as fish habitat in Bering Sea submarine canyons.

    Directory of Open Access Journals (Sweden)

    Robert J Miller

    Full Text Available Continental margins are dynamic, heterogeneous settings that can include canyons, seamounts, and banks. Two of the largest canyons in the world, Zhemchug and Pribilof, cut into the edge of the continental shelf in the southeastern Bering Sea. Here currents and upwelling interact to produce a highly productive area, termed the Green Belt, that supports an abundance of fishes and squids as well as birds and marine mammals. We show that in some areas the floor of these canyons harbors high densities of gorgonian and pennatulacean corals and sponges, likely due to enhanced surface productivity, benthic currents and seafloor topography. Rockfishes, including the commercially important Pacific ocean perch, Sebastes alutus, were associated with corals and sponges as well as with isolated boulders. Sculpins, poachers and pleuronectid flounders were also associated with corals in Pribilof Canyon, where corals were most abundant. Fishes likely use corals and sponges as sources of vertical relief, which may harbor prey as well as provide shelter from predators. Boulders may be equivalent habitat in this regard, but are sparse in the canyons, strongly suggesting that biogenic structure is important fish habitat. Evidence of disturbance to the benthos from fishing activities was observed in these remote canyons. Bottom trawling and other benthic fishing gear has been shown to damage corals and sponges that may be very slow to recover from such disturbance. Regulation of these destructive practices is key to conservation of benthic habitats in these canyons and the ecosystem services they provide.

  12. Structure-forming corals and sponges and their use as fish habitat in Bering Sea submarine canyons.

    Science.gov (United States)

    Miller, Robert J; Hocevar, John; Stone, Robert P; Fedorov, Dmitry V

    2012-01-01

    Continental margins are dynamic, heterogeneous settings that can include canyons, seamounts, and banks. Two of the largest canyons in the world, Zhemchug and Pribilof, cut into the edge of the continental shelf in the southeastern Bering Sea. Here currents and upwelling interact to produce a highly productive area, termed the Green Belt, that supports an abundance of fishes and squids as well as birds and marine mammals. We show that in some areas the floor of these canyons harbors high densities of gorgonian and pennatulacean corals and sponges, likely due to enhanced surface productivity, benthic currents and seafloor topography. Rockfishes, including the commercially important Pacific ocean perch, Sebastes alutus, were associated with corals and sponges as well as with isolated boulders. Sculpins, poachers and pleuronectid flounders were also associated with corals in Pribilof Canyon, where corals were most abundant. Fishes likely use corals and sponges as sources of vertical relief, which may harbor prey as well as provide shelter from predators. Boulders may be equivalent habitat in this regard, but are sparse in the canyons, strongly suggesting that biogenic structure is important fish habitat. Evidence of disturbance to the benthos from fishing activities was observed in these remote canyons. Bottom trawling and other benthic fishing gear has been shown to damage corals and sponges that may be very slow to recover from such disturbance. Regulation of these destructive practices is key to conservation of benthic habitats in these canyons and the ecosystem services they provide.

  13. A slow-forming isopeptide bond in the structure of the major pilin SpaD from Corynebacterium diphtheriae has implications for pilus assembly

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Hae Joo; Paterson, Neil G. [University of Auckland, Private Bag 92019, Auckland 1142 (New Zealand); Kim, Chae Un [Cornell University, Ithaca, NY 14853 (United States); Middleditch, Martin [University of Auckland, Private Bag 92019, Auckland 1142 (New Zealand); Chang, Chungyu; Ton-That, Hung [University of Texas–Houston Medical School, Houston, TX 77030 (United States); Baker, Edward N., E-mail: ted.baker@auckland.ac.nz [University of Auckland, Private Bag 92019, Auckland 1142 (New Zealand)

    2014-05-01

    Two crystal structures of the major pilin SpaD from C. diphtheriae have been determined at 1.87 and 2.5 Å resolution. The N-terminal domain is found to contain an isopeptide bond that forms slowly over time in the recombinant protein. Given its structural context, this provides insight into the relationship between internal isopeptide-bond formation and pilus assembly. The Gram-positive organism Corynebacterium diphtheriae, the cause of diphtheria in humans, expresses pili on its surface which it uses for adhesion and colonization of its host. These pili are covalent protein polymers composed of three types of pilin subunit that are assembled by specific sortase enzymes. A structural analysis of the major pilin SpaD, which forms the polymeric backbone of one of the three types of pilus expressed by C. diphtheriae, is reported. Mass-spectral and crystallographic analysis shows that SpaD contains three internal Lys–Asn isopeptide bonds. One of these, shown by mass spectrometry to be located in the N-terminal D1 domain of the protein, only forms slowly, implying an energy barrier to bond formation. Two crystal structures, of the full-length three-domain protein at 2.5 Å resolution and of a two-domain (D2-D3) construct at 1.87 Å resolution, show that each of the three Ig-like domains contains a single Lys–Asn isopeptide-bond cross-link, assumed to give mechanical stability as in other such pili. Additional stabilizing features include a disulfide bond in the D3 domain and a calcium-binding loop in D2. The N-terminal D1 domain is more flexible than the others and, by analogy with other major pilins of this type, the slow formation of its isopeptide bond can be attributed to its location adjacent to the lysine used in sortase-mediated polymerization during pilus assembly.

  14. Self-powdering and nonlinear optical domain structures in ferroelastic β'-Gd2(MoO4)3 crystals formed in glass

    International Nuclear Information System (INIS)

    Tsukada, Y.; Honma, T.; Komatsu, T.

    2009-01-01

    Ferroelastic β'-Gd 2 (MoO 4 ) 3 , (GMO), crystals are formed through the crystallization of 21.25Gd 2 O 3 -63.75MoO 3 -15B 2 O 3 glass (mol%), and two scientific curious phenomena are observed. (1) GMO crystals formed in the crystallization break into small pieces with a triangular prism or pyramid shape having a length of 50-500 μm spontaneously during the crystallizations in the inside of an electric furnace, not during the cooling in air after the crystallization. This phenomenon is called 'self-powdering phenomenon during crystallization' in this paper. (2) Each self-powdered GMO crystal grain shows a periodic domain structure with different refractive indices, and a spatially periodic second harmonic generation (SHG) depending on the domain structure is observed. It is proposed from polarized micro-Raman scattering spectra and the azimuthal dependence of second harmonic intensities that GMO crystals are oriented in each crystal grain and the orientation of (MoO 4 ) 2- tetrahedra in GMO crystals changes periodically due to spontaneous strains in ferroelastic GMO crystals. - Graphical abstract: This figure shows the polarized optical photograph at room temperature for a particle (piece) obtained by a heat treatment of the glass at 590 deg. C for 2 h in an electric furnace in air. This particle was obtained through the self-powdering behavior in the crystallization of glass. The periodic domain structure is observed. Ferroelastic β'-Gd 2 (MoO 4 ) 3 crystals are formed in the particle, and second harmonic generations are detected, depending on the domain structure.

  15. Escherichia coli DnaA forms helical structures along the longitudinal cell axis distinct from MreB filaments.

    Science.gov (United States)

    Boeneman, Kelly; Fossum, Solveig; Yang, Yanhua; Fingland, Nicholas; Skarstad, Kirsten; Crooke, Elliott

    2009-05-01

    DnaA initiates chromosomal replication in Escherichia coli at a well-regulated time in the cell cycle. To determine how the spatial distribution of DnaA is related to the location of chromosomal replication and other cell cycle events, the localization of DnaA in living cells was visualized by confocal fluorescence microscopy. The gfp gene was randomly inserted into a dnaA-bearing plasmid via in vitro transposition to create a library that included internally GFP-tagged DnaA proteins. The library was screened for the ability to rescue dnaA(ts) mutants, and a candidate gfp-dnaA was used to replace the dnaA gene of wild-type cells. The resulting cells produce close to physiological levels of GFP-DnaA from the endogenous promoter as their only source of DnaA and somewhat under-initiate replication with moderate asynchrony. Visualization of GFP-tagged DnaA in living cells revealed that DnaA adopts a helical pattern that spirals along the long axis of the cell, a pattern also seen in wild-type cells by immunofluorescence with affinity purified anti-DnaA antibody. Although the DnaA helices closely resemble the helices of the actin analogue MreB, co-visualization of GFP-tagged DnaA and RFP-tagged MreB demonstrates that DnaA and MreB adopt discrete helical structures along the length of the longitudinal cell axis.

  16. Schizosaccharomyces pombe Rad22A and Rad22B have similar biochemical properties and form multimeric structures

    Energy Technology Data Exchange (ETDEWEB)

    Vries, Femke A.T. de [Department of Toxicogenetics, Leiden University Medical Center, P.O. Box 9600, 2300 RC Leiden (Netherlands); Zonneveld, Jose B.M. [Department of Toxicogenetics, Leiden University Medical Center, P.O. Box 9600, 2300 RC Leiden (Netherlands); Groot, Anton J. de [Department of Toxicogenetics, Leiden University Medical Center, P.O. Box 9600, 2300 RC Leiden (Netherlands); Koning, Roman I. [Department of Molecular Cell Biology, Leiden University Medical Center, Leiden (Netherlands); Zeeland, Albert A. van [Department of Toxicogenetics, Leiden University Medical Center, P.O. Box 9600, 2300 RC Leiden (Netherlands); Pastink, Albert [Department of Toxicogenetics, Leiden University Medical Center, P.O. Box 9600, 2300 RC Leiden (Netherlands)]. E-mail: A.Pastink@lumc.nl

    2007-02-03

    The Saccharomyces cerevisiae Rad52 protein has a crucial role in the repair of DNA double-strand breaks by homologous recombination. In vitro, Rad52 displays DNA binding and strand annealing activities and promotes Rad51-mediated strand exchange. Schizosaccharomyces pombe has two Rad52 homologues, Rad22A and Rad22B. Whereas rad22A deficient strains exhibit severe defects in repair and recombination, rad22B mutants have a much less severe phenotype. To better understand the role of Rad22A and Rad22B in double-strand break repair, both proteins were purified to near homogeneity. Using gel retardation and filter binding assays, binding of Rad22A and Rad22B to short single-stranded DNAs was demonstrated. Binding of Rad22A to double-stranded oligonucleotides or linearized plasmid molecules containing blunt ends or short single-stranded overhangs could not be detected. Rad22B also does not bind efficiently to short duplex oligonucleotides but binds readily to DNA fragments containing 3'-overhangs. Rad22A as well as Rad22B efficiently promote annealing of complementary single-stranded DNAs. In the presence of Rad22A annealing of complementary DNAs is almost 90%. Whereas in reactions containing Rad22B the maximum level of annealing is 60%, most likely due to inhibition of the reaction by duplex DNA. Gel-filtration experiments and electron microscopic analyses indicate self-association of Rad22A and Rad22B and the formation of multimeric structures as has been observed for Rad52 in yeast and man.

  17. EVOLUTION OF GASEOUS DISK VISCOSITY DRIVEN BY SUPERNOVA EXPLOSION. II. STRUCTURE AND EMISSIONS FROM STAR-FORMING GALAXIES AT HIGH REDSHIFT

    International Nuclear Information System (INIS)

    Yan Changshuo; Wang Jianmin

    2010-01-01

    High spatial resolution observations show that high-redshift galaxies are undergoing intensive evolution of dynamical structure and morphologies displayed by the Hα, Hβ, [O III], and [N II] images. It has been shown that supernova explosion (SNexp) of young massive stars during the star formation epoch, as kinetic feedback to host galaxies, can efficiently excite the turbulent viscosity. We incorporate the feedback into the dynamical equations through mass dropout and angular momentum transportation driven by the SNexp-excited turbulent viscosity. The empirical Kennicutt-Schmidt law is used for star formation rates (SFRs). We numerically solve the equations and show that there can be intensive evolution of structure of the gaseous disk. Secular evolution of the disk shows interesting characteristics: (1) high viscosity excited by SNexp can efficiently transport the gas from 10 kpc to ∼1 kpc forming a stellar disk whereas a stellar ring forms for the case with low viscosity; (2) starbursts trigger SMBH activity with a lag of ∼10 8 yr depending on SFRs, prompting the joint evolution of SMBHs and bulges; and (3) the velocity dispersion is as high as ∼100 km s -1 in the gaseous disk. These results are likely to vary with the initial mass function (IMF) that the SNexp rates rely on. Given the IMF, we use the GALAXEV code to compute the spectral evolution of stellar populations based on the dynamical structure. In order to compare the present models with the observed dynamical structure and images, we use the incident continuum from the simple stellar synthesis and CLOUDY to calculate emission line ratios of Hα, Hβ, [O III], and [N II], and Hα brightness of gas photoionized by young massive stars formed on the disks. The models can produce the main features of emission from star-forming galaxies. We apply the present model to two galaxies, BX 389 and BX 482 observed in the SINS high-z sample, which are bulge and disk-dominated, respectively. Two successive

  18. Using ALMA to Resolve the Nature of the Early Star-Forming Large-Scale Structure G073

    Science.gov (United States)

    Hill, R.; Kneissl, R.; Polletta, M.; Clarenc, B.; Dole, H. A.; Nesvadba, N. P. H.; Scott, D.; Béthermin, M.; Lagache, G.; Montier, L.

    2017-07-01

    Galaxy clusters at large redshift are key targets for understanding the nature of the early Universe, yet locating them has proven to be very challenging. Recently, a large sample of over 2000 high-z candidate structures have been found using Planck's all-sky submillimetre maps, and a subset of 234 have been followed up with Herschel-SPIRE, which showed that the emission can be attributed to large far-infrared overdensities. However, the individual galaxies giving rise to the emission seen by Planck and Herschel have not yet been resolved nor characterized, so we do not yet know whether these sources are the progenitors of present-day, massive galaxy clusters. In an attempt to address this, we targeted the eight brightest Herschel-SPIRE peaks in the centre of the Planck peak G073.4-57.5 using ALMA at 1.3 mm, and complemented these observations with multi-wavelength data from Spitzer-IRAC at 3.6 and 4.5 μm and from CFHT-WIRCam at 1.2 and 2.2 μm. We also utilize data on G073.4-57.5 at 850 μm from JCMT's SCUBA-2 instrument. We detect a total of 18 millimetre galaxies brighter than 0.3mJy in 2.4arcmin2. In every case we are able to match these to their NIR counterparts, and while the most significant SCUBA-2 sources are not included in the ALMA pointings, we find an 8σ detection when stacking the ALMA source positions in the 850 μm data. We derive photometric redshifts, IR luminosities, star-formation rates, stellar masses, dust temperatures, and dust masses; the photometric redshifts are concentrated around z ≃ 1 and z ≃ 2 and the NIR colours show a "red" sequence, while the star-formation rates indicate that three of the galaxies are "starbursts". Serendipitous CO line detections of two of the galaxies appear to match their photometric redshifts with z = 2.05. We find that the ALMA source density is 8-30 times higher than average background estimates, and thus also larger than seen in typical "proto-cluster" fields. The evidence seems to be indicating the

  19. [Structure of Relationships Formed by Occupational Health Nurses for Co-operating with Managers to Support Workers with Mental Health Concerns].

    Science.gov (United States)

    Hatanaka, Junko; Takasaki, Masako; Hatanaka, Michiyo

    2018-05-31

    Occupational health staff and managers play important roles in supporting workers with mental health concerns and mutual co-operation among them is a necessary element. However, when co-operating with other professionals, several problems arise that often make such co-operation a challenge. Effective mutual actions are needed to promote such co-operation, and relationships must be formed for this purpose. Therefore, in this study, we aimed to clarify how occupational health nurses form relationships for facilitating co-operation with managers to provide support to workers with mental health concerns. Data were collected using semi-structured interviews with 11 occupational health nurses who provide individualized mental health support and who have at least 5 years of experience as occupational health nurses. Analysis of the recorded interviews was performed using a qualitative statistical method (KJ method). Six elements that constitute the formation of relationships were identified. When occupational health nurses form relationships for facilitating co-operation with a manager to provide support to workers, they "form relationships through strategic communication" with them and when co-operation is required, they form a relationship by "acting in a manner that suits the manager," such as his/her character and the situation. To support this relationship, occupational health nurses "provide mental support to the manager" by listening to his/her anxiety or real intention about supporting the subordinate with mental health concerns and provide relief while understanding their burdens during the co-operation. Occupational health nurses even "provide support to the manager in their activities," which assessed the situation at the workplace as the specialist and advised the manager to understand how to concern to the subordinate specifically. In addition, they "indirectly support the manager" which included coordinating with the concerned persons so as to not excessively

  20. Structural Basis for Catalysis by the Mono and Dimetalated forms of the dapE-encoded N-succinyl-L,L-Diaminopimelic Acid Desuccinylase

    Science.gov (United States)

    Nocek, Boguslaw P.; Gillner, Danuta M.; Fan, Yao; Holz, Richard C.; Joachimiak, Andrzej

    2010-01-01

    Biosynthesis of lysine and meso-diaminopimelic acid in bacteria provides essential components for protein synthesis and construction of the bacterial peptidoglycan cell wall. The dapE operon enzymes synthesize both meso-diaminopimelic acid and lysine and, therefore, represent a potential targets for novel antibacterials. The dapE-encoded N-succinyl-L,L-diaminopimelic acid desuccinylase functions in a late step of the pathway and converts N-succinyl-L,L-diaminopimelic acid (L,L-SDAP) to L,L-diaminopimelic acid and succinate. Deletion of the dapE gene is lethal to Helicobacter pylori and Mycobacterium smegmatis indicating that DapE’s are essential for cell growth and proliferation. Since there are no similar pathways in humans, inhibitors that target DapE may have selective toxicity against only bacteria. A major limitation in developing antimicrobial agents that target DapE has been the lack of structural information. Herein we report the high-resolution X-ray crystal structures of the DapE from Haemophilus influenzae with one and two zinc ions bound in the active site, respectively. These two forms show different activity. Based on these newly determined structures we propose a revised catalytic mechanism of peptide bond cleavage by DapE enzymes. These structures provide important insight into catalytic mechanism of DapE enzymes as well as a structural foundation that is critical for the rational design of DapE inhibitors. PMID:20138056