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Sample records for potential matrix elements

  1. Dipole transition matrix elements for systems with power-law potentials

    SciTech Connect

    Grant, A.K.; Rosner, J.L. )

    1992-11-01

    We study the behavior of dipole matrix elements for systems bound by power-law potentials of the form {ital V}({ital r}){similar to}{ital r}{sup {alpha}}, which are useful in the descriptions of quarkonium systems. The experimental feature for which further understanding is sought is the apparent suppression of the transition {Upsilon}(3{ital S}){r arrow}{chi}{sub {ital b}}{gamma}. We find that this matrix element actually vanishes in a power-law potential {ital r}{sup {alpha}} for a certain power {alpha}{sub 0}{approx}{minus}0.4. The suppression of transitions between states with different numbers of nodes in their radial wave functions is a universal property of most physically interesting power-law potentials. We derive results in the limit of large orbital angular momenta {ital l}, checking that they agree with the known answers for the Coulomb and spherical oscillator potentials. For states with {ital n}{sub {ital r}} nodes in their radial wave functions, we find that the matrix elements {l angle}{ital n}{sub {ital r}},{ital l}{vert bar}{ital r}{vert bar}{ital n}{sub {ital r}},{ital l}+1{r angle} behave as {ital l}{sup 2/(2+{alpha})} for small {ital n}{sub {ital r}} and large {ital l}. Transitions with {Delta}{ital n}{sub {ital r}}={plus minus}1 behave with respect to those with {Delta}{ital n}{sub {ital r}}=0 as const/ {radical}{ital l}, with constants calculated for each {ital n}{sub {ital r}}. Moreover, we find that {l angle}{ital n}{sub {ital r}}=0,{ital l}{vert bar}{ital r}{vert bar}{ital n}{sub {ital r}}=2,{ital l}{minus}1{r angle}/{l angle}{ital n}{sub {ital r}}=0, {ital l}{vert bar}{ital r}{vert bar}{ital n}{sub {ital r}}=0,{ital l}+1{r angle}{r arrow}{Phi}({alpha})/{ital l} as {ital l}{r arrow}{infinity}, where {Phi}({alpha}) is calculated explicitly.

  2. Relativistic Dipole Matrix Element Zeros

    NASA Astrophysics Data System (ADS)

    Lajohn, L. A.; Pratt, R. H.

    2002-05-01

    There is a special class of relativistic high energy dipole matrix element zeros (RZ), whose positions with respect to photon energy ω , only depend on the bound state l quantum number according to ω^0=mc^2/(l_b+1) (independent of primary quantum number n, nuclear charge Z, central potential V and dipole retardation). These RZ only occur in (n,l_b,j_b)arrow (ɛ , l_b+1,j_b) transitions such as ns_1/2arrow ɛ p_1/2; np_3/2arrow ɛ d_3/2: nd_5/2arrow ɛ f_5/2 etc. The nonrelativistic limit of these matrix elements can be established explicitly in the Coulomb case. Within the general matrix element formalism (such as that in [1]); when |κ | is substituted for γ in analytic expressions for matrix elements, the zeros remain, but ω^0 now becomes dependent on n and Z. When the reduction to nonrelativistic form is completed by application of the low energy approximation ω mc^2 mc^2, the zeros disappear. This nonzero behavior was noted in nonrelativistic dipole Coulomb matrix elements by Fano and Cooper [2] and later proven by Oh and Pratt[3]. (J. H. Scofield, Phys. Rev. A 40), 3054 (1989 (U. Fano and J. W. Cooper, Rev. Mod. Phys. 40), 441 (1968). (D. Oh and R. H. Pratt, Phys. Rev. A 34), 2486 (1986); 37, 1524 (1988); 45, 1583 (1992).

  3. Potential and matrix elements of the hamiltonian of internal rotation in molecules in the basis set of Mathieu functions

    NASA Astrophysics Data System (ADS)

    Turovtsev, V. V.; Orlov, Yu. D.; Tsirulev, A. N.

    2015-08-01

    The advantages of the orthonormal basis set of 2π-periodic Mathieu functions compared to the trigonometric basis set in calculations of torsional states of molecules are substantiated. Explicit expressions are derived for calculating the Hamiltonian matrix elements of a one-dimensional torsional Schrödinger equation with a periodic potential of the general form in the basis set of Mathieu functions. It is shown that variation of a parameter of Mathieu functions allows the rotation potential and the structural function to be approximated with a good accuracy by a small number of series terms. The conditions for the best choice of this parameter are specified, and approximations are obtained for torsional potentials of n-butane upon rotation about the central C-C bond and of its univalent radical n-butyl C2H5C·H2 upon rotation of the C·H2 group. All algorithms are implemented in the Maple package.

  4. Matrix Elements for Hylleraas CI

    NASA Astrophysics Data System (ADS)

    Harris, Frank E.

    The limitation to at most a single interelectron distance in individual configurations of a Hylleraas-type multiconfiguration wave function restricts significantly the types of integrals occurring in matrix elements for energy calculations, but even then if the formulation is not handled efficiently the angular parts of these integrals escalate to create expressions of great complexity. This presentation reviews ways in which the angular-momentum calculus can be employed to systematize and simplify the matrix element formulas, particularly those for the kinetic-energy matrix elements.

  5. Exact tensor hypercontraction: a universal technique for the resolution of matrix elements of local finite-range N-body potentials in many-body quantum problems.

    PubMed

    Parrish, Robert M; Hohenstein, Edward G; Schunck, Nicolas F; Sherrill, C David; Martínez, Todd J

    2013-09-27

    Configuration-space matrix elements of N-body potentials arise naturally and ubiquitously in the Ritz-Galerkin solution of many-body quantum problems. For the common specialization of local, finite-range potentials, we develop the exact tensor hypercontraction method, which provides a quantized renormalization of the coordinate-space form of the N-body potential, allowing for a highly separable tensor factorization of the configuration-space matrix elements. This representation allows for substantial computational savings in chemical, atomic, and nuclear physics simulations, particularly with respect to difficult "exchangelike" contractions. PMID:24116775

  6. POTHMF: A program for computing potential curves and matrix elements of the coupled adiabatic radial equations for a hydrogen-like atom in a homogeneous magnetic field

    NASA Astrophysics Data System (ADS)

    Chuluunbaatar, O.; Gusev, A. A.; Gerdt, V. P.; Rostovtsev, V. A.; Vinitsky, S. I.; Abrashkevich, A. G.; Kaschiev, M. S.; Serov, V. V.

    2008-02-01

    A FORTRAN 77 program is presented which calculates with the relative machine precision potential curves and matrix elements of the coupled adiabatic radial equations for a hydrogen-like atom in a homogeneous magnetic field. The potential curves are eigenvalues corresponding to the angular oblate spheroidal functions that compose adiabatic basis which depends on the radial variable as a parameter. The matrix elements of radial coupling are integrals in angular variables of the following two types: product of angular functions and the first derivative of angular functions in parameter, and product of the first derivatives of angular functions in parameter, respectively. The program calculates also the angular part of the dipole transition matrix elements (in the length form) expressed as integrals in angular variables involving product of a dipole operator and angular functions. Moreover, the program calculates asymptotic regular and irregular matrix solutions of the coupled adiabatic radial equations at the end of interval in radial variable needed for solving a multi-channel scattering problem by the generalized R-matrix method. Potential curves and radial matrix elements computed by the POTHMF program can be used for solving the bound state and multi-channel scattering problems. As a test desk, the program is applied to the calculation of the energy values, a short-range reaction matrix and corresponding wave functions with the help of the KANTBP program. Benchmark calculations for the known photoionization cross-sections are presented. Program summaryProgram title:POTHMF Catalogue identifier:AEAA_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEAA_v1_0.html Program obtainable from:CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions:Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.:8123 No. of bytes in distributed program, including test data

  7. Weak matrix elements for CP violation.

    SciTech Connect

    Lee, W.; Gupta, R.; Christ, N.; Fleming, G. T.; Kilcup, G.; Liu, G.; Mawhinney, R.; Sharpe, S.; Wu, L.; Bhattacharya, T.

    2001-01-01

    We present preliminary results of matrix elements of four fermion operators relevant to the determination of e and E ' / E using staggered fermions. To calculate the matrix elements relevant to CP violation in Kaon decays it is important to use a lattice formulation which preserves (some) chiral symmetry.

  8. Measuring strangeness matrix elements of the nucleon

    SciTech Connect

    Henley, E.M.; Pollock, S.J. ); Krein, G. Instituto de Fisica Teorica , Sao Paulo, SP ); Williams, A.G. Florida State Univ., Tallahassee, FL )

    1991-01-01

    Experiments are proposed to measure various strangeness matrix elements of the nucleon. Examples are electro- and neutrino- production of phi mesons and the difference between neutrino and antineutrino scattering from isospin zero targets, e.g., deuterons.

  9. Measuring strangeness matrix elements of the nucleon

    SciTech Connect

    Henley, E.M.; Pollock, S.J.; Krein, G. |; Williams, A.G. |

    1991-12-31

    Experiments are proposed to measure various strangeness matrix elements of the nucleon. Examples are electro- and neutrino- production of phi mesons and the difference between neutrino and antineutrino scattering from isospin zero targets, e.g., deuterons.

  10. Rolling Element Bearing Stiffness Matrix Determination (Presentation)

    SciTech Connect

    Guo, Y.; Parker, R.

    2014-01-01

    Current theoretical bearing models differ in their stiffness estimates because of different model assumptions. In this study, a finite element/contact mechanics model is developed for rolling element bearings with the focus of obtaining accurate bearing stiffness for a wide range of bearing types and parameters. A combined surface integral and finite element method is used to solve for the contact mechanics between the rolling elements and races. This model captures the time-dependent characteristics of the bearing contact due to the orbital motion of the rolling elements. A numerical method is developed to determine the full bearing stiffness matrix corresponding to two radial, one axial, and two angular coordinates; the rotation about the shaft axis is free by design. This proposed stiffness determination method is validated against experiments in the literature and compared to existing analytical models and widely used advanced computational methods. The fully-populated stiffness matrix demonstrates the coupling between bearing radial, axial, and tilting bearing deflections.

  11. Interaction matrix element fluctuations in quantum dots

    SciTech Connect

    Kaplan, L.; Alhassid, Y.

    2008-04-04

    In the Coulomb blockade regime of a ballistic quantum dot, the distribution of conductance peak spacings is well known to be incorrectly predicted by a single-particle picture; instead, matrix element fluctuations of the residual electronic interaction need to be taken into account. In the normalized random-wave model, valid in the semiclassical limit where the number of electrons in the dot becomes large, we obtain analytic expressions for the fluctuations of two-body and one-body matrix elements. However, these fluctuations may be too small to explain low-temperature experimental data. We have examined matrix element fluctuations in realistic chaotic geometries, and shown that at energies of experimental interest these fluctuations generically exceed by a factor of about 3-4 the predictions of the random wave model. Even larger fluctuations occur in geometries with a mixed chaotic-regular phase space. These results may allow for much better agreement between the Hartree-Fock picture and experiment. Among other findings, we show that the distribution of interaction matrix elements is strongly non-Gaussian in the parameter range of experimental interest, even in the random wave model. We also find that the enhanced fluctuations in realistic geometries cannot be computed using a leading-order semiclassical approach, but may be understood in terms of short-time dynamics.

  12. Proton decay matrix elements from lattice QCD

    SciTech Connect

    Aoki, Yasumichi; Shintani, Eigo; Collaboration: RBC Collaboration; UKQCD Collaboration

    2012-07-27

    We report on the calculation of the matrix elements of nucleon to pseudoscalar decay through a three quark operator, a part of the low-energy, four-fermion, baryon-number-violating operator originating from grand unified theories. The direct calculation of the form factors using domain-wall fermions on the lattice, incorporating the u, d and s sea-quarks effects yields the results with all the relevant systematic uncertainties controlled for the first time.

  13. Analytical Derivations of Single-Particle Matrix Elements in Nuclear Shell Model

    NASA Astrophysics Data System (ADS)

    Fatah, Aziz H.; Radhi, R. A.; Abdullah, Nzar R.

    2016-07-01

    We present analytical method to calculate single particle matrix elements used in atomic and nuclear physics. We show seven different formulas of matrix elements of the operator f(r)dr m where f(r) = rμ, rμ jJ(qr), V(r) corresponding to the Gaussian and the Yukawa potentials used in nuclear shell models and nuclear structure. In addition, we take into account a general integral formula of the matrix element that covers all seven matrix elements obtained analytically.

  14. Staggered fermion matrix elements using smeared operators

    NASA Astrophysics Data System (ADS)

    Kilcup, Greg; Gupta, Rajan; Sharpe, Stephen R.

    1998-02-01

    We investigate the use of two kinds of staggered fermion operators, smeared and unsmeared. The smeared operators extend over a 44 hypercube, and tend to have smaller perturbative corrections than the corresponding unsmeared operators. We use these operators to calculate kaon weak matrix elements on quenched ensembles at β=6.0, 6.2, and 6.4. Extrapolating to the continuum limit, we find BK(NDR,2 GeV)=0.62+/-0.02(stat)+/-0.02(syst). The systematic error is dominated by the uncertainty in the matching between lattice and continuum operators due to the truncation of perturbation theory at one loop. We do not include any estimate of the errors due to quenching or to the use of degenerate s and d quarks. For the ΔI=3/2 electromagnetic penguin operators we find B(3/2)7=0.62+/-0.03+/-0.06 and B(3/2)8=0.77+/-0.04+/-0.04. We also use the ratio of unsmeared to smeared operators to make a partially nonperturbative estimate of the renormalization of the quark mass for staggered fermions. We find that tadpole improved perturbation theory works well if the coupling is chosen to be αMS¯(q*=1/a).

  15. Specific interaction of mutant p53 with regions of matrix attachment region DNA elements (MARs) with a high potential for base-unpairing

    PubMed Central

    Will, Katrin; Warnecke, Gabriele; Wiesmüller, Lisa; Deppert, Wolfgang

    1998-01-01

    Mutant, but not wild-type p53 binds with high affinity to a variety of MAR-DNA elements (MARs), suggesting that MAR-binding of mutant p53 relates to the dominant-oncogenic activities proposed for mutant p53. MARs recognized by mutant p53 share AT richness and contain variations of an AATATATTT “DNA-unwinding motif,” which enhances the structural dynamics of chromatin and promotes regional DNA base-unpairing. Mutant p53 specifically interacted with MAR-derived oligonucleotides carrying such unwinding motifs, catalyzing DNA strand separation when this motif was located within a structurally labile sequence environment. Addition of GC-clamps to the respective MAR-oligonucleotides or introducing mutations into the unwinding motif strongly reduced DNA strand separation, but supported the formation of tight complexes between mutant p53 and such oligonucleotides. We conclude that the specific interaction of mutant p53 with regions of MAR-DNA with a high potential for base-unpairing provides the basis for the high-affinity binding of mutant p53 to MAR-DNA. PMID:9811860

  16. Precision measurement of transition matrix elements via light shift cancellation.

    PubMed

    Herold, C D; Vaidya, V D; Li, X; Rolston, S L; Porto, J V; Safronova, M S

    2012-12-14

    We present a method for accurate determination of atomic transition matrix elements at the 10(-3) level. Measurements of the ac Stark (light) shift around "magic-zero" wavelengths, where the light shift vanishes, provide precise constraints on the matrix elements. We make the first measurement of the 5s - 6p matrix elements in rubidium by measuring the light shift around the 421 and 423 nm zeros through diffraction of a condensate off a sequence of standing wave pulses. In conjunction with existing theoretical and experimental data, we find 0.3235(9)ea(0) and 0.5230(8)ea(0) for the 5s - 6p(1/2) and 5s - 6p(3/2) elements, respectively, an order of magnitude more accurate than the best theoretical values. This technique can provide needed, accurate matrix elements for many atoms, including those used in atomic clocks, tests of fundamental symmetries, and quantum information. PMID:23368314

  17. Excited State Effects in Nucleon Matrix Element Calculations

    SciTech Connect

    Constantia Alexandrou, Martha Constantinou, Simon Dinter, Vincent Drach, Karl Jansen, Theodoros Leontiou, Dru B Renner

    2011-12-01

    We perform a high-statistics precision calculation of nucleon matrix elements using an open sink method allowing us to explore a wide range of sink-source time separations. In this way the influence of excited states of nucleon matrix elements can be studied. As particular examples we present results for the nucleon axial charge g{sub A} and for the first moment of the isovector unpolarized parton distribution x{sub u-d}. In addition, we report on preliminary results using the generalized eigenvalue method for nucleon matrix elements. All calculations are performed using N{sub f} = 2+1+1 maximally twisted mass Wilson fermions.

  18. Analytical expressions for vibrational matrix elements of Morse oscillators

    SciTech Connect

    Zuniga, J.; Hidalgo, A.; Frances, J.M.; Requena, A.; Lopez Pineiro, A.; Olivares del Valle, F.J.

    1988-10-15

    Several exact recursion relations connecting different Morse oscillator matrix elements associated with the operators q/sup ..cap alpha../e/sup -//sup ..beta..//sup aq/ and q/sup ..cap alpha../e/sup -//sup ..beta..//sup aq/(d/dr) are derived. Matrix elements of the other useful operators may then be obtained easily. In particular, analytical expressions for (y/sup k/d/dr) and (y/sup k/d/dr+(d/dr)y/sup k/), matrix elements of interest in the study of the internuclear motion in polyatomic molecules, are obtained.

  19. Analytic formula for quadrupole-quadrupole matrix elements

    NASA Astrophysics Data System (ADS)

    Rosensteel, G.

    1990-12-01

    An analytic formula is reported for general matrix elements of the microscopic quadrupole-quadrupole operator in the U(3)-boson approximation. The complete infinite-dimensional basis of A-fermion wave functions is compatible with the harmonic-oscillator shell model and consists of np-nh configurations, with spurious center-of-mass excitations removed, which are symmetry adapted to the Elliott U(3) and symplectic Sp(3,R) models. The formula expresses the general Q2.Q2 matrix element with respect to this complete orthonormal basis as a Racah SU(3) U coefficient times a closed-shell matrix element. An oscillator closed-shell matrix element of Q2.Q2 is a square root of a rational function of the integer quantum numbers of the U(3) basis.

  20. Automatic generation of matrix element derivatives for tight binding models

    NASA Astrophysics Data System (ADS)

    Elena, Alin M.; Meister, Matthias

    2005-10-01

    Tight binding (TB) models are one approach to the quantum mechanical many-particle problem. An important role in TB models is played by hopping and overlap matrix elements between the orbitals on two atoms, which of course depend on the relative positions of the atoms involved. This dependence can be expressed with the help of Slater-Koster parameters, which are usually taken from tables. Recently, a way to generate these tables automatically was published. If TB approaches are applied to simulations of the dynamics of a system, also derivatives of matrix elements can appear. In this work we give general expressions for first and second derivatives of such matrix elements. Implemented in a tight binding computer program, like, for instance, DINAMO, they obviate the need to type all the required derivatives of all occurring matrix elements by hand.

  1. The dynamic stiffness matrix of two-dimensional elements: application to Kirchhoff's plate continuous elements

    NASA Astrophysics Data System (ADS)

    Casimir, J. B.; Kevorkian, S.; Vinh, T.

    2005-10-01

    This paper describes a procedure for building the dynamic stiffness matrix of two-dimensional elements with free edge boundary conditions. The dynamic stiffness matrix is the basis of the continuous element method. Then, the formulation is used to build a Kirchhoff rectangular plate element. Gorman's method of boundary condition decomposition and Levy's series are used to obtain the strong solution of the elementary problem. A symbolic computation software partially performs the construction of the dynamic stiffness matrix from this solution. The performances of the element are evaluated from comparisons with harmonic responses of plates obtained by the finite element method.

  2. Numerical matrix method for quantum periodic potentials

    NASA Astrophysics Data System (ADS)

    Le Vot, Felipe; Meléndez, Juan J.; Yuste, Santos B.

    2016-06-01

    A numerical matrix methodology is applied to quantum problems with periodic potentials. The procedure consists essentially in replacing the true potential by an alternative one, restricted by an infinite square well, and in expressing the wave functions as finite superpositions of eigenfunctions of the infinite well. A matrix eigenvalue equation then yields the energy levels of the periodic potential within an acceptable accuracy. The methodology has been successfully used to deal with problems based on the well-known Kronig-Penney (KP) model. Besides the original model, these problems are a dimerized KP solid, a KP solid containing a surface, and a KP solid under an external field. A short list of additional problems that can be solved with this procedure is presented.

  3. Acceleration of matrix element computations for precision measurements

    SciTech Connect

    Brandt, Oleg; Gutierrez, Gaston; Wang, M. H.L.S.; Ye, Zhenyu

    2014-11-25

    The matrix element technique provides a superior statistical sensitivity for precision measurements of important parameters at hadron colliders, such as the mass of the top quark or the cross-section for the production of Higgs bosons. The main practical limitation of the technique is its high computational demand. Using the example of the top quark mass, we present two approaches to reduce the computation time of the technique by a factor of 90. First, we utilize low-discrepancy sequences for numerical Monte Carlo integration in conjunction with a dedicated estimator of numerical uncertainty, a novelty in the context of the matrix element technique. We then utilize a new approach that factorizes the overall jet energy scale from the matrix element computation, a novelty in the context of top quark mass measurements. The utilization of low-discrepancy sequences is of particular general interest, as it is universally applicable to Monte Carlo integration, and independent of the computing environment.

  4. Neutrinoless double-β decay and nuclear transition matrix elements

    SciTech Connect

    Rath, P. K.

    2015-10-28

    Within mechanisms involving the light Majorana neutrinos, squark-neutrino, Majorons, sterile neutrinos and heavy Majorana neutrino, nuclear transition matrix elements for the neutrinoless (β{sup −}β{sup −}){sub 0ν} decay of {sup 96}Zr, {sup 100}Mo, {sup 128,130}Te and {sup 150}Nd nuclei are calculated by employing the PHFB approach. Effects due to finite size of nucleons, higher order currents, short range correlations, and deformations of parent as well as daughter nuclei on the calculated matrix elements are estimated. Uncertainties in nuclear transition matrix elements within long-ranged mechanisms but for double Majoron accompanied (β{sup −}β{sup −}ϕϕ){sub 0ν} decay modes are 9%–15%. In the case of short ranged heavy Majorona neutrino exchange mechanism, the maximum uncertainty is about 35%. The maximum systematic error within the mechanism involving the exchange of light Majorana neutrino is about 46%.

  5. Effective potential in density matrix functional theory.

    PubMed

    Nagy, A; Amovilli, C

    2004-10-01

    In the previous paper it was shown that in the ground state the diagonal of the spin independent second-order density matrix n can be determined by solving a single auxiliary equation of a two-particle problem. Thus the problem of an arbitrary system with even electrons can be reduced to a two-particle problem. The effective potential of the two-particle equation contains a term v(p) of completely kinetic origin. Virial theorem and hierarchy of equations are derived for v(p) and simple approximations are proposed. A relationship between the effective potential u(p) of the shape function equation and the potential v(p) is established.

  6. Effective potential in density matrix functional theory.

    PubMed

    Nagy, A; Amovilli, C

    2004-10-01

    In the previous paper it was shown that in the ground state the diagonal of the spin independent second-order density matrix n can be determined by solving a single auxiliary equation of a two-particle problem. Thus the problem of an arbitrary system with even electrons can be reduced to a two-particle problem. The effective potential of the two-particle equation contains a term v(p) of completely kinetic origin. Virial theorem and hierarchy of equations are derived for v(p) and simple approximations are proposed. A relationship between the effective potential u(p) of the shape function equation and the potential v(p) is established. PMID:15473719

  7. Distributions of off-diagonal scattering matrix elements: Exact results

    SciTech Connect

    Nock, A. Kumar, S. Sommers, H.-J. Guhr, T.

    2014-03-15

    Scattering is a ubiquitous phenomenon which is observed in a variety of physical systems which span a wide range of length scales. The scattering matrix is the key quantity which provides a complete description of the scattering process. The universal features of scattering in chaotic systems is most generally modeled by the Heidelberg approach which introduces stochasticity to the scattering matrix at the level of the Hamiltonian describing the scattering center. The statistics of the scattering matrix is obtained by averaging over the ensemble of random Hamiltonians of appropriate symmetry. We derive exact results for the distributions of the real and imaginary parts of the off-diagonal scattering matrix elements applicable to orthogonally-invariant and unitarily-invariant Hamiltonians, thereby solving a long standing problem. -- Highlights: •Scattering problem in complex or chaotic systems. •Heidelberg approach to model the chaotic nature of the scattering center. •A novel route to the nonlinear sigma model based on the characteristic function. •Exact results for the distributions of off-diagonal scattering-matrix elements. •Universal aspects of the scattering-matrix fluctuations.

  8. Some measurements for determining strangeness matrix elements in the nucleon

    SciTech Connect

    Henley, E.M.; Pollock, S.J.; Ying, S.; Frederico, T.; Krein,; Williams, A.G.

    1991-12-31

    Some experiments to measure strangeness matrix elements of the proton are proposed. Two of these suggestions are described in some detail, namely electro-production of phi mesons and the difference between neutrino and antineutrino scattering for isospin zero targets such as deuterium.

  9. Some measurements for determining strangeness matrix elements in the nucleon

    SciTech Connect

    Henley, E.M.; Pollock, S.J.; Ying, S. ); Frederico, T. , Sao Jose dos Campos, SP . Inst. de Estudos Avancados); Krein, . Inst. de Fisica Teorica); Williams, A.G. )

    1991-01-01

    Some experiments to measure strangeness matrix elements of the proton are proposed. Two of these suggestions are described in some detail, namely electro-production of phi mesons and the difference between neutrino and antineutrino scattering for isospin zero targets such as deuterium.

  10. Differential equation for the spherical dipole matrix elements of hydrogen

    SciTech Connect

    Price, P.N.; Harmin, D.A. )

    1990-09-01

    A differential equation in {ital l} for hydrogenic radial dipole matrix elements is generated from the recursion relations of Infeld and Hull (Rev. Mod. Phys. 23, 31 (1951)). The equation is valid for all ({ital n},{ital n}{prime}){much gt}1, for all {vert bar}{Delta}{ital n}{vert bar}{ital ieq}{vert bar}{ital n}{prime}{minus}{ital n}{vert bar}, and for bound-free transitions from excited states. Approximate solutions are obtained for the case {ital l}{much lt}{ital n} and are found to be equivalent to those of other workers when {vert bar}{Delta}{ital n}{vert bar}{much gt}1. We also present a power-series solution in {ital l} good for all {vert bar}{Delta}{ital n}{vert bar}. General features of the dependence of the matrix elements on {ital l} are explained.

  11. Magic wavelengths, matrix elements, polarizabilities, and lifetimes of Cs

    NASA Astrophysics Data System (ADS)

    Safronova, M. S.; Safronova, U. I.; Clark, Charles W.

    2016-07-01

    Motivated by recent interest in their applications, we report a systematic study of Cs atomic properties calculated by a high-precision relativistic all-order method. Excitation energies, reduced matrix elements, transition rates, and lifetimes are determined for levels with principal quantum numbers n ≤12 and orbital angular momentum quantum numbers l ≤3 . Recommended values and estimates of uncertainties are provided for a number of electric-dipole transitions and the electric dipole polarizabilities of the n s , n p , and n d states. We also report a calculation of the electric quadrupole polarizability of the ground state. We display the dynamic polarizabilities of the 6 s and 7 p states for optical wavelengths between 1160 and 1800 nm and identify corresponding magic wavelengths for the 6 s -7 p1 /2 and 6 s -7 p3 /2 transitions. The values of relevant matrix elements needed for polarizability calculations at other wavelengths are provided.

  12. Glueball Spectrum and Matrix Elements on Anisotropic Lattices

    SciTech Connect

    Y. Chen; A. Alexandru; S.J. Dong; T. Draper; I. Horvath; F.X. Lee; K.F. Liu; N. Mathur; C. Morningstar; M. Peardon; S. Tamhankar; B.L. Young; J.B. Zhang

    2006-01-01

    The glueball-to-vacuum matrix elements of local gluonic operators in scalar, tensor, and pseudoscalar channels are investigated numerically on several anisotropic lattices with the spatial lattice spacing ranging from 0.1fm - 0.2fm. These matrix elements are needed to predict the glueball branching ratios in J/{psi} radiative decays which will help identify the glueball states in experiments. Two types of improved local gluonic operators are constructed for a self-consistent check and the finite volume effects are studied. We find that lattice spacing dependence of our results is very weak and the continuum limits are reliably extrapolated, as a result of improvement of the lattice gauge action and local operators. We also give updated glueball masses with various quantum numbers.

  13. Calculation of transition matrix elements by nonsingular orbital transformations

    NASA Astrophysics Data System (ADS)

    Kývala, Mojmír

    A general strategy is described for the evaluation of transition matrix elements between pairs of full class CI wave functions built up from mutually nonorthogonal molecular orbitals. A new method is proposed for the counter-transformation of the linear expansion coefficients of a full CI wave function under a nonsingular transformation of the molecular-orbital basis. The method, which consists in a straightforward application of the Cauchy-Binet formula to the definition of a Slater determinant, is shown to be simple and suitable for efficient implementation on current high-performance computers. The new method appears mainly beneficial to the calculation of miscellaneous transition matrix elements among individually optimized CASSCF states and to the re-evaluation of the CASCI expansion coefficients in Slater-determinant bases formed from arbitrarily rotated (e.g., localized or, conversely, delocalized) active molecular orbitals.

  14. [Electron transfer between globular proteins. Evaluation of a matrix element].

    PubMed

    Lakhno, V D; Chuev, G N; Ustinin, M N

    1998-01-01

    The dependence of the matrix element of the probability of interprotein electron transfer on the mutual orientation of the donor and acceptor centers and the distance between them was calculated. The calculations were made under the assumption that electron transfer proceeds mainly by a collective excitation of polaron nature, like a solvated electron state. The results obtained are consistent with experimental data and indicate the nonexponential behavior of this dependence in the case when the distance transfer is less than 20 A.

  15. A stochastic method for computing hadronic matrix elements

    SciTech Connect

    Alexandrou, Constantia; Constantinou, Martha; Dinter, Simon; Drach, Vincent; Jansen, Karl; Hadjiyiannakou, Kyriakos; Renner, Dru B.

    2014-01-24

    In this study, we present a stochastic method for the calculation of baryon 3-point functions which is an alternative to the typically used sequential method offering more versatility. We analyze the scaling of the error of the stochastically evaluated 3-point function with the lattice volume and find a favorable signal to noise ratio suggesting that the stochastic method can be extended to large volumes providing an efficient approach to compute hadronic matrix elements and form factors.

  16. Weak matrix elements on the lattice - Circa 1995

    SciTech Connect

    Soni, A.

    1995-10-03

    Status of weak matrix elements is reviewed. In particular, e{prime}/e, B {yields} K*{gamma}, B{sub B} and B{sub B}, are discussed and the overall situation with respect to the lattice effort and some of its phenomenological implications are summarised. For e{prime}/e the need for the relevant matrix elements is stressed in view of the forthcoming improved experiments. For some of the operators, (e.g. O{sub 6}), even bound on their matrix elements would be very helpful. On B {yields} K{degrees}{gamma}, a constant behavior of T{sub 2} appears disfavored although dependence of T{sub 2} could, of course, be milder than a simple pole. Improved data is badly needed to settle this important issue firmly, especially in view of its ramification for extractions of V{sub td} from B {yields} {rho}{gamma}. On B{sub {kappa}}, the preliminary result from JLQCD appears to contradict Sharpe et al. JLQCD data seems to fit very well to linear {alpha} dependence and leads to an appreciably lower value of B{sub {kappa}}. Four studies of B{sub {kappa}} in the {open_quotes}full{close_quotes} (n{sub f} = 2) theory indicate very little quenching effects on B{sub {kappa}}; the full theory value seems to be just a little less than the quenched result. Based on expectations from HQET, analysis of B-parameter (B{sub h}{ell}) for the heavy-light mesons via B{sub h}{ell}) = constant + constants{prime}/m{sub h}{ell} is suggested. A summary of an illustrative sample of hadron matrix elements is given and constraints on CKM parameters (e.g. V{sub td}/V{sub ts}, on the unitarity triangle and on x{sub s}/x{sub d}, emerging from the lattice calculations along with experimental results are briefly discussed. In quite a few cases, for the first time, some indication of quenching errors on weak matrix elements are now becoming available.

  17. Multi-jet Merging with NLO Matrix Elements

    SciTech Connect

    Siegert, Frank; Hoche, Stefan; Krauss, Frank; Schonherr, Marek; /Dresden, Tech. U.

    2011-08-18

    In the algorithm presented here, the ME+PS approach to merge samples of tree-level matrix elements into inclusive event samples is combined with the POWHEG method, which includes exact next-to-leading order matrix elements in the parton shower. The advantages of the method are discussed and the quality of its implementation in SHERPA is exemplified by results for e{sup +}e{sup -} annihilation into hadrons at LEP, for deep-inelastic lepton-nucleon scattering at HERA, for Drell-Yan lepton-pair production at the Tevatron and for W{sup +}W{sup -}-production at LHC energies. The simulation of hard QCD radiation in parton-shower Monte Carlos has seen tremendous progress over the last years. It was largely stimulated by the need for more precise predictions at LHC energies where the large available phase space allows additional hard QCD radiation alongside known Standard Model processes or even signals from new physics. Two types of algorithms have been developed, which allow to improve upon the soft-collinear approximations made in the parton shower, such that hard radiation is simulated according to exact matrix elements. In the ME+PS approach [1] higher-order tree-level matrix elements for different final-state jet multiplicity are merged with each other and with subsequent parton shower emissions to generate an inclusive sample. Such a prescription is invaluable for analyses which are sensitive to final states with a large jet multiplicity. The only remaining deficiency of such tree-level calculations is the large uncertainty stemming from scale variations. The POWHEG method [2] solves this problem for the lowest multiplicity subprocess by combining full NLO matrix elements with the parton shower. While this leads to NLO accuracy in the inclusive cross section and the exact radiation pattern for the first emission, it fails to describe higher-order emissions with improved accuracy. Thus it is not sufficient if final states with high jet multiplicities are considered

  18. Acceleration of matrix element computations for precision measurements

    DOE PAGES

    Brandt, Oleg; Gutierrez, Gaston; Wang, M. H.L.S.; Ye, Zhenyu

    2014-11-25

    The matrix element technique provides a superior statistical sensitivity for precision measurements of important parameters at hadron colliders, such as the mass of the top quark or the cross-section for the production of Higgs bosons. The main practical limitation of the technique is its high computational demand. Using the example of the top quark mass, we present two approaches to reduce the computation time of the technique by a factor of 90. First, we utilize low-discrepancy sequences for numerical Monte Carlo integration in conjunction with a dedicated estimator of numerical uncertainty, a novelty in the context of the matrix elementmore » technique. We then utilize a new approach that factorizes the overall jet energy scale from the matrix element computation, a novelty in the context of top quark mass measurements. The utilization of low-discrepancy sequences is of particular general interest, as it is universally applicable to Monte Carlo integration, and independent of the computing environment.« less

  19. SYMBMAT: Symbolic computation of quantum transition matrix elements

    NASA Astrophysics Data System (ADS)

    Ciappina, M. F.; Kirchner, T.

    2012-08-01

    We have developed a set of Mathematica notebooks to compute symbolically quantum transition matrices relevant for atomic ionization processes. The utilization of a symbolic language allows us to obtain analytical expressions for the transition matrix elements required in charged-particle and laser induced ionization of atoms. Additionally, by using a few simple commands, it is possible to export these symbolic expressions to standard programming languages, such as Fortran or C, for the subsequent computation of differential cross sections or other observables. One of the main drawbacks in the calculation of transition matrices is the tedious algebraic work required when initial states other than the simple hydrogenic 1s state need to be considered. Using these notebooks the work is dramatically reduced and it is possible to generate exact expressions for a large set of bound states. We present explicit examples of atomic collisions (in First Born Approximation and Distorted Wave Theory) and laser-matter interactions (within the Dipole and Strong Field Approximations and different gauges) using both hydrogenic wavefunctions and Slater-Type Orbitals with arbitrary nlm quantum numbers as initial states. Catalogue identifier: AEMI_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEMI_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC license, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 71 628 No. of bytes in distributed program, including test data, etc.: 444 195 Distribution format: tar.gz Programming language: Mathematica Computer: Single machines using Linux or Windows (with cores with any clock speed, cache memory and bits in a word) Operating system: Any OS that supports Mathematica. The notebooks have been tested under Windows and Linux and with versions 6.x, 7.x and 8.x Classification: 2.6 Nature of problem

  20. Calculation of hadronic matrix elements using lattice QCD

    SciTech Connect

    Gupta, R.

    1993-08-01

    The author gives a brief introduction to the scope of lattice QCD calculations in his effort to extract the fundamental parameters of the standard model. This goal is illustrated by two examples. First the author discusses the extraction of CKM matrix elements from measurements of form factors for semileptonic decays of heavy-light pseudoscalar mesons such as D {yields} Ke{nu}. Second, he presents the status of results for the kaon B parameter relevant to CP violation. He concludes the talk with a short outline of his experiences with optimizing QCD codes on the CM5.

  1. Matrix effects in PIXE elemental analysis of thick calculi targets

    NASA Astrophysics Data System (ADS)

    Kwiatek, Wojciech M.; Lekki, Janusz; Nowak, Tomasz; Dutkiewicz, Erazm M.; Paluszkiewicz, Czeslawa

    1997-02-01

    The PIXE technique for Trace Element Analysis have been applied to the studies of mineral deposits such as kidney stones in human organism. The calculi mainly composed of phosphates, oxalates and uric acid were extracted during surgical operations and were measured at the proton beam as thick targets. Trace elements studies of such samples are influenced by the thick targets matrix effects and by the sample composition changes caused by energy deposition in the target due to the proton beam irradiation. These both difficulties are especially pronounced in the case of the biological samples. In this paper the procedure dealing with the above problems is described, basing on calculations with the use of principal formula for the detected X-ray yields and two complementary techniques for PIXE experiments such as Fourier Transform InfraRed Spectroscopy (FTIR) and Elastic Back Scattering (EBS). A rough estimation of sample chemical composition was achieved by means of the FTIR analysis, which also may serve as a tool for local sample temperature estimation during beam irradiation. Composition of major target elements, needed for beam stopping and X-rays attenuation calculations were determined using the EBS technique applied simultaneously with PIXE. The above approach was used to estimate elemental contents of several samples. Comparison between traditionally calculated and improved results is presented.

  2. Constraining neutrinoless double β decay matrix elements in 130Te

    NASA Astrophysics Data System (ADS)

    McAllister, S. A.; Kay, B. P.; Freeman, S. J.; Schiffer, J. P.; Diebel, C. M.; Bloxham, T.; Howard, A. M.; Parker, P. D.; Sharp, D. K.; Thomas, J. S.

    2012-09-01

    If a reliable measurement of a neutrinoless double beta decay (0v2β) rate is made, the effective neutrino masses can be determined from the nuclear matrix element. Theoretical calculations of nuclear matrix elements, however, show some disagreement. To test the suitability of various theoretical models, they should be benchmarked against experimentally measured nuclear properties, such as the ground-state distribution of nucleons in the parent-daughter nuclei, and how they change as a result of the decay process. Single neutron-adding reactions have been performed on the 0v2β candidate nucleus, 130Te. The Macfarlane-French sum rules have then been used to determine the single-particle vacancies. Some quasi-random phase approximations (QRPA) can greatly simplify theoretical calculations by describing the ground state of even-even nuclei using a BCS wavefunction. This assumption has been tested using two-neutron removal, (p,t) reactions. The BCS wavefunction appeared to be a valid approximation for valence neutrons.

  3. Matching tree-level matrix elements with interleaved showers

    NASA Astrophysics Data System (ADS)

    Lönnblad, Leif; Prestel, Stefan

    2012-03-01

    We present an implementation of the so-called Ckkw-l merging scheme for combining multi-jet tree-level matrix elements with parton showers. The implementation uses the transverse-momentum-ordered shower with interleaved multiple interactions as implemented in P YTHIA8. We validate our procedure using e+e--annihilation into jets and vector boson production in hadronic collisions, with special attention to details in the algorithm which are formally sub-leading in character, but may have visible effects in some observables. We find substantial merging scale dependencies induced by the enforced rapidity ordering in the default P YTHIA8 shower. If this rapidity ordering is removed the merging scale dependence is almost negligible. We then also find that the shower does a surprisingly good job of describing the hardness of multi-jet events, as long as the hardest couple of jets are given by the matrix elements. The effects of using interleaved multiple interactions as compared to more simplistic ways of adding underlying-event effects in vector boson production are shown to be negligible except in a few sensitive observables. To illustrate the generality of our implementation, we also give some example results from di-boson production and pure QCD jet production in hadronic collisions.

  4. SYMBMAT: Symbolic computation of quantum transition matrix elements

    NASA Astrophysics Data System (ADS)

    Ciappina, M. F.; Kirchner, T.

    2012-08-01

    We have developed a set of Mathematica notebooks to compute symbolically quantum transition matrices relevant for atomic ionization processes. The utilization of a symbolic language allows us to obtain analytical expressions for the transition matrix elements required in charged-particle and laser induced ionization of atoms. Additionally, by using a few simple commands, it is possible to export these symbolic expressions to standard programming languages, such as Fortran or C, for the subsequent computation of differential cross sections or other observables. One of the main drawbacks in the calculation of transition matrices is the tedious algebraic work required when initial states other than the simple hydrogenic 1s state need to be considered. Using these notebooks the work is dramatically reduced and it is possible to generate exact expressions for a large set of bound states. We present explicit examples of atomic collisions (in First Born Approximation and Distorted Wave Theory) and laser-matter interactions (within the Dipole and Strong Field Approximations and different gauges) using both hydrogenic wavefunctions and Slater-Type Orbitals with arbitrary nlm quantum numbers as initial states. Catalogue identifier: AEMI_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEMI_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC license, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 71 628 No. of bytes in distributed program, including test data, etc.: 444 195 Distribution format: tar.gz Programming language: Mathematica Computer: Single machines using Linux or Windows (with cores with any clock speed, cache memory and bits in a word) Operating system: Any OS that supports Mathematica. The notebooks have been tested under Windows and Linux and with versions 6.x, 7.x and 8.x Classification: 2.6 Nature of problem

  5. Analytical finite element matrix elements and global matrix assembly for hierarchical 3-D vector basis functions within the hybrid finite element boundary integral method

    NASA Astrophysics Data System (ADS)

    Li, L.; Wang, K.; Li, H.; Eibert, T. F.

    2014-11-01

    A hybrid higher-order finite element boundary integral (FE-BI) technique is discussed where the higher-order FE matrix elements are computed by a fully analytical procedure and where the gobal matrix assembly is organized by a self-identifying procedure of the local to global transformation. This assembly procedure applys to both, the FE part as well as the BI part of the algorithm. The geometry is meshed into three-dimensional tetrahedra as finite elements and nearly orthogonal hierarchical basis functions are employed. The boundary conditions are implemented in a strong sense such that the boundary values of the volume basis functions are directly utilized within the BI, either for the tangential electric and magnetic fields or for the asssociated equivalent surface current densities by applying a cross product with the unit surface normals. The self-identified method for the global matrix assembly automatically discerns the global order of the basis functions for generating the matrix elements. Higher order basis functions do need more unknowns for each single FE, however, fewer FEs are needed to achieve the same satisfiable accuracy. This improvement provides a lot more flexibility for meshing and allows the mesh size to raise up to λ/3. The performance of the implemented system is evaluated in terms of computation time, accuracy and memory occupation, where excellent results with respect to precision and computation times of large scale simulations are found.

  6. S-matrix pole trajectories for Yukawa potentials

    SciTech Connect

    Roriz, L.A.L.; Delfino, A.

    1988-08-01

    Using the two-body K matrix extended to the whole complex-momentum plane, we construct the S matrix as a function of the strength lambda of attractive Yukawa potentials. By varying lambda we study pole trajectories for the s, p, and d waves.

  7. Placing three-dimensional isoparametric elements into NASTRAN. [alterations in matrix assembly to simplify generation of higher order elements

    NASA Technical Reports Server (NTRS)

    Newman, M. B.; Filstrup, A. W.

    1973-01-01

    Linear (8 node), parabolic (20 node), cubic (32 node) and mixed (some edges linear, some parabolic and some cubic) have been inserted into NASTRAN, level 15.1. First the dummy element feature was used to check out the stiffness matrix generation routines for the linear element in NASTRAN. Then, the necessary modules of NASTRAN were modified to include the new family of elements. The matrix assembly was changed so that the stiffness matrix of each isoparametric element is only generated once as the time to generate these higher order elements tends to be much longer than the other elements in NASTRAN. This paper presents some of the experiences and difficulties of inserting a new element or family of elements into NASTRAN.

  8. Shell model nuclear matrix elements for competing mechanisms contributing to double beta decay

    SciTech Connect

    Horoi, Mihai

    2013-12-30

    Recent progress in the shell model approach to the nuclear matrix elements for the double beta decay process are presented. This includes nuclear matrix elements for competing mechanisms to neutrionless double beta decay, a comparison between closure and non-closure approximation for {sup 48}Ca, and an updated shell model analysis of nuclear matrix elements for the double beta decay of {sup 136}Xe.

  9. A top quark mass measurement using a matrix element method

    SciTech Connect

    Linacre, Jacob Thomas

    2009-01-01

    A measurement of the mass of the top quark is presented, using top-antitop pair (t$\\bar{t}$) candidate events for the lepton+jets decay channel. The measurement makes use of Tevatron p$\\bar{p}$ collision data at centre-of-mass energy √s = 1.96 TeV, collected at the CDF detector. The top quark mass is measured by employing an unbinned maximum likelihood method where the event probability density functions are calculated using signal (t$\\bar{t}$) and background (W+jets) matrix elements, as well as a set of parameterised jet-to-parton mapping functions. The likelihood function is maximised with respect to the top quark mass, the fraction of signal events, and a correction to the jet energy scale (JES) of the calorimeter jets. The simultaneous measurement of the JES correction (ΔJES) provides an in situ jet energy calibration based on the known mass of the hadronically decaying W boson. Using 578 lepton+jets candidate events corresponding to 3.2 fb -1 of integrated luminosity, the top quark mass is measured to be mt = 172.4± 1.4 (stat+ΔJES) ±1.3 (syst) GeV=c2, one of the most precise single measurements to date.

  10. Controlling excited-state contamination in nucleon matrix elements

    NASA Astrophysics Data System (ADS)

    Yoon, Boram; Gupta, Rajan; Bhattacharya, Tanmoy; Engelhardt, Michael; Green, Jeremy; Joó, Bálint; Lin, Huey-Wen; Negele, John; Orginos, Kostas; Pochinsky, Andrew; Richards, David; Syritsyn, Sergey; Winter, Frank; Nucleon Matrix Elements NME Collaboration

    2016-06-01

    We present a detailed analysis of methods to reduce statistical errors and excited-state contamination in the calculation of matrix elements of quark bilinear operators in nucleon states. All the calculations were done on a 2 +1 -flavor ensemble with lattices of size 323×64 generated using the rational hybrid Monte Carlo algorithm at a =0.081 fm and with Mπ=312 MeV . The statistical precision of the data is improved using the all-mode-averaging method. We compare two methods for reducing excited-state contamination: a variational analysis and a 2-state fit to data at multiple values of the source-sink separation tsep. We show that both methods can be tuned to significantly reduce excited-state contamination and discuss their relative advantages and cost effectiveness. A detailed analysis of the size of source smearing used in the calculation of quark propagators and the range of values of tsep needed to demonstrate convergence of the isovector charges of the nucleon to the tsep→∞ estimates is presented.

  11. North African geology: exploration matrix for potential major hydrocarbon discoveries

    SciTech Connect

    Kanes, W.H.; O'Connor, T.E.

    1985-02-01

    Based on results and models presented previously, it is possible to consider an exploration matrix that examines the 5 basic exploration parameters: source, reservoir, timing, structure, and seal. This matrix indicates that even those basins that have had marginal exploration successes, including the Paleozoic megabasin and downfaulted Triassic grabens of Morocco, the Cyrenaican platform of Libya, and the Tunisia-Sicily shelf, have untested plays. The exploration matrix also suggests these high-risk areas could change significantly, if one of the 5 basic matrix parameters is upgraded or if adjustments in political or financial risk are made. The Sirte basin and the Gulf of Suez, 2 of the more intensely explored areas, also present attractive matrix prospects, particularly with deeper Nubian beds or with the very shallow Tertiary sections. The Ghadames basin of Libya and Tunisia shows some potential, but its evaluation responds strongly to stratigraphic and external nongeologic matrix variations based on degree of risk exposure to be assumed. Of greatest risk in the matrix are the very deep Moroccan Paleozoic clastic plays and the Jurassic of Sinai. However, recent discoveries may upgrade these untested frontier areas. Based on the matrix generated by the data presented at a North African Petroleum Geology symposium, significant hydrocarbon accumulations are yet to be found. The remaining questions are: where in the matrix does each individual company wish to place its exploration capital and how much should be the risk exposure.

  12. Maple code for the calculation of the matrix elements of the Boltzmann collision operators for mixtures

    NASA Astrophysics Data System (ADS)

    Shizgal, Bernie D.; Dridi, Raouf

    2010-09-01

    A Maple code is provided which is used to compute the matrix elements of the collision operators in the Boltzmann equation for arbitrary differential elastic collision cross section. The present paper describes an efficient method for the calculation of the matrix elements of the collision operators in the Sonine basis set. The method employs the generating functions for these polynomials. The transport properties of gaseous mixtures of atoms and/or ions are generally determined from solutions of the Boltzmann equation. The solution of the Boltzmann equation for the velocity distribution functions requires a representation of the integral collision operators defined by the differential cross sections describing collisions between pairs of particles. Many applications have considered either the simple hard sphere cross section or the cross section corresponding to the inverse fourth power of the inter-particle distance ("Maxwell molecules"). There are a few applications where realistic quantum mechanical cross sections have been used. The basis set of Sonine (or Laguerre) polynomials is the basis set of choice used to represent the distribution functions. The Maple code provided is used to express the matrix elements of the collision operators in terms of a finite sum of the omega integrals of transport theory and defined by the differential cross section. Thus the matrix representations of the collision operators are applicable to arbitrary interaction potentials. Program summaryProgram title: MCBC Catalogue identifier: AEGJ_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEGJ_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 2422 No. of bytes in distributed program, including test data, etc.: 48 653 Distribution format: tar.gz Programming language: Maple

  13. Dirac matrices as elements of a superalgebraic matrix algebra

    NASA Astrophysics Data System (ADS)

    Monakhov, V. V.

    2016-08-01

    The paper considers a Clifford extension of the Grassmann algebra, in which operators are built from Grassmann variables and by the derivatives with respect to them. It is shown that a subalgebra which is isomorphic to the usual matrix algebra exists in this algebra, the Clifford exten-sion of the Grassmann algebra is a generalization of the matrix algebra and contains superalgebraic operators expanding matrix algebra and produces supersymmetric transformations.

  14. Destructive interference of E2 matrix elements in a triaxial rotor model

    NASA Astrophysics Data System (ADS)

    Allmond, J. M.; Wood, J. L.; Kulp, W. D.

    2010-05-01

    A triaxial rotor model with independent inertia and electric quadrupole tensors is applied to nuclei that have certain E2 matrix elements equal to zero. It is shown that such vanishing E2 matrix elements are explained by the model as a destructive interference effect. The example of Pt196 is considered.

  15. Destructive interference of E2 matrix elements in a triaxial rotor model

    SciTech Connect

    Allmond, James M; Wood, J. L.; Kulp, W. D.

    2010-01-01

    A triaxial rotor model with independent inertia and electric quadrupole tensors is applied to nuclei that have certain E2 matrix elements equal to zero. It is shown that such vanishing E2 matrix elements are explained by the model as a destructive interference effect. The example of 196Pt is considered.

  16. Application of the Finite-Element Z-Matrix Method to e-H2 Collisions

    NASA Technical Reports Server (NTRS)

    Huo, Winifred M.; Brown, David; Langhoff, Stephen R. (Technical Monitor)

    1997-01-01

    The present study adapts the Z-matrix formulation using a mixed basis of finite elements and Gaussians. This is a energy-independent basis which allows flexible boundary conditions and is amenable to efficient algorithms for evaluating the necessary matrix elements with molecular targets.

  17. Double scaling limit for matrix models with nonanalytic potentials

    NASA Astrophysics Data System (ADS)

    Shcherbina, Mariya

    2008-03-01

    We study the double scaling limit for unitary invariant ensembles of random matrices with nonanalytic potentials and find the asymptotic expansion for the entries of the corresponding Jacobi matrix. Our approach is based on the perturbation expansion for the string equations. The first order perturbation terms of the Jacobi matrix coefficients are expressed through the Hastings-McLeod solution of the Painleve II equation. The limiting reproducing kernel is expressed in terms of solutions of the Dirac system of differential equations with a potential defined by the first order terms of the expansion.

  18. Determination of configuration matrix element and outer synchronization among networks with different topologies

    NASA Astrophysics Data System (ADS)

    Lü, Ling; Liu, Shuo; Li, Gang; Zhao, Guannan; Gu, Jiajia; Tian, Jing; Wang, Zhouyang

    2016-11-01

    In this paper, we research the outer synchronization among discrete networks with different topologies. Based on Lyapunov theorem, a novel synchronization technique is designed. Further, the control inputs of the networks and the adaptive laws of configuration matrix element are obtained. In the end, a numerical example is given to illustrate the effectiveness of the synchronization technique. It is found that the designed control input of the networks ensures the convergence of the errors among the networks to zero. And the designed adaptive law of configuration matrix element can replace effectively configuration matrix element in networks.

  19. Universal evolution of Cabibbo-Kobayashi-Maskawa matrix elements

    SciTech Connect

    Barger, V.; Berger, M.S.; Ohmann, P. . Dept. of Physics)

    1993-03-01

    We derive the two-loop evolution equations for the Cabibbo-Kobayashi-Maskawa (CKM) matrix. We show that to leading order in the mass and CKM hierarchies the scaling of the mixings [vert bar][ital V][sub [ital u][ital b

  20. Motivation of concepts for the negative ion extraction from a single element of the matrix source.

    PubMed

    Lishev, St; Shivarova, A; Yordanov, D

    2016-02-01

    A single element of a matrix source of negative hydrogen ions (a planar-coil inductively driven small-radius discharge equipped with an extraction system) is studied regarding the ion extraction. Since the spatial distribution of the negative ions obeys that of the dc potential, the latter is controlled by applying a high bias to the plasma electrode of the extraction system. This leads to discharge maintenance by both rf and dc power deposition and, respectively, to similarities with the axial profile of the dc potential in the glow discharges. The discharge length, the applied rf power, and the bias to the plasma electrode and its radius are the parameters varied in determination of proper conditions for the ion extraction. PMID:26931997

  1. Zn Isotopes in Chondrites, Chondrules, and Matrix: Origin of the Volatile Element Depletion in Chondrites

    NASA Astrophysics Data System (ADS)

    Moynier, F.; Pringle, E.; Hezel, D.

    2015-07-01

    The variations of Zn isotope ratios among carbonaceous chondrites show that the volatile element depletion in solar system material occurred in the solar nebula. We will also present the Zn isotopic composition of chondrules and matrix from carbonaceous chondrites.

  2. A nodal spectral stiffness matrix for the finite-element method

    NASA Astrophysics Data System (ADS)

    Bittencourt, Marco L.; Vazquez, Thais G.

    2008-12-01

    In this paper, shape functions are proposed for the spectral finite-element method aiming to finding a nodal spectral stiffness matrix. The proposed shape functions obtain a nearly diagonal 1D stiffness matrix with better conditioning than using the Lagrange and Jacobi bases.

  3. Calculation of Radiative Corrections to E1 matrix elements in the Neutral Alkalis

    SciTech Connect

    Sapirstein, J; Cheng, K T

    2004-09-28

    Radiative corrections to E1 matrix elements for ns-np transitions in the alkali metal atoms lithium through francium are evaluated. They are found to be small for the lighter alkalis but significantly larger for the heavier alkalis, and in the case of cesium much larger than the experimental accuracy. The relation of the matrix element calculation to a recent decay rate calculation for hydrogenic ions is discussed, and application of the method to parity nonconservation in cesium is described.

  4. Calculation Of Two Neutrino Double Beta Decay Nuclear Matrix Elements For 128,130Te

    SciTech Connect

    Uenlue, S.; Salamov, D. I.; Babacan, T.; Kuecuekbursa, A.

    2006-04-26

    Based on Pyatov-Salamov method, spin-isospin (Gamow-Teller) effective interaction strength parameter has been found self-consistently. Then, the problem has been solved within the framework of QRPA. Gamow-Teller matrix elements for both {beta}- and {beta}+ transitions and two neutrino double beta decay nuclear matrix elements have been calculated for 128,130Te{yields}128,130Xe transitions. The obtained results have been compared with the corresponding experimental data and other theoretical results.

  5. Matrix inflation and the landscape of its potential

    SciTech Connect

    Ashoorioon, Amjad; Firouzjahi, Hassan; Sheikh-Jabbari, Mohammmad Mahdi E-mail: firouz@ipm.ir

    2010-05-01

    Recently we introduced an inflationary setup in which the inflaton fields are matrix valued scalar fields with a generic quartic potential, M-flation. In this work we study the landscape of various inflationary models arising from M-flation. The landscape of the inflationary potential arises from the dynamics of concentric multiple branes in appropriate flux compactifications of string theory. After discussing the classical landscape of the theory we study the possibility of transition among various inflationary models appearing at different points on the landscape, mapping the quantum landscape of M-flation. As specific examples, we study some two-field inflationary models arising from this theory in the landscape.

  6. Generalized ray-transfer matrix for an optical element having an arbitrary wavefront aberration.

    PubMed

    Jeong, Tae Moon; Ko, Do-Kyeong; Lee, Jongmin

    2005-11-15

    A generalized ray-transfer matrix for describing the action of an optical element having an arbitrary wavefront aberration is obtained. In this generalized ray-transfer matrix, the action of the aberrated optical element is represented by the product of radial ray-transfer matrices and tangential ray-transfer matrices. The refraction angle of an incident ray is calculated from the gradient of the wavefront aberration at the point of incidence, and the radial and tangential ray-transfer matrices directly use the gradient as a matrix component. To show the validity of the generalized ray-transfer matrix, intercept heights from a spot diagram are calculated with the generalized ray-transfer matrix and compared with those calculated with commercial ray-tracing software.

  7. Matrix elements and duality for type 2 unitary representations of the Lie superalgebra gl(m|n)

    SciTech Connect

    Werry, Jason L.; Gould, Mark D.; Isaac, Phillip S.

    2015-12-15

    The characteristic identity formalism discussed in our recent articles is further utilized to derive matrix elements of type 2 unitary irreducible gl(m|n) modules. In particular, we give matrix element formulae for all gl(m|n) generators, including the non-elementary generators, together with their phases on finite dimensional type 2 unitary irreducible representations which include the contravariant tensor representations and an additional class of essentially typical representations. Remarkably, we find that the type 2 unitary matrix element equations coincide with the type 1 unitary matrix element equations for non-vanishing matrix elements up to a phase.

  8. Matrix elements and duality for type 2 unitary representations of the Lie superalgebra gl(m|n)

    NASA Astrophysics Data System (ADS)

    Werry, Jason L.; Gould, Mark D.; Isaac, Phillip S.

    2015-12-01

    The characteristic identity formalism discussed in our recent articles is further utilized to derive matrix elements of type 2 unitary irreducible gl(m|n) modules. In particular, we give matrix element formulae for all gl(m|n) generators, including the non-elementary generators, together with their phases on finite dimensional type 2 unitary irreducible representations which include the contravariant tensor representations and an additional class of essentially typical representations. Remarkably, we find that the type 2 unitary matrix element equations coincide with the type 1 unitary matrix element equations for non-vanishing matrix elements up to a phase.

  9. Symbolic algorithms for the computation of Moshinsky brackets and nuclear matrix elements

    NASA Astrophysics Data System (ADS)

    Ursescu, D.; Tomaselli, M.; Kuehl, T.; Fritzsche, S.

    2005-12-01

    . Method of solution:Moshinsky's transformation brackets as well as two-nucleon matrix elements are provided within the framework of MAPLE. The transformation brackets are evaluated recursively for a given number of shells and utilized for the computation of the two-particle matrix elements for different coupling schemes and interactions. Moreover, a simple notation has been introduced to handle the two-particle nuclear states in ll-, LSJ-, and jj-coupling, both in the center-of-well and the relative and center-of-mass coordinates. Restrictions onto the complexity of the problem:The program supports in principle an arbitrary number of shell states with the only limitation given by the computer resources themselves. Typically, the time requirements for the recursive computation of the Moshinsky brackets and matrix elements increase rapidly with the number of the allowed shell states but can be reduced significantly by the pre-calculation of the transformation brackets. Unusual features of the program:Moshinsky brackets are computed and provided in either numeric, algebraic or some symbolic form. In addition, the two-particle matrix elements are calculated for a scalar potential, spin-orbit coupling and tensorial forces, both in floating-point and algebraic notation. All two-particle matrix elements are expressed in terms of the Talmi integrals but can be evaluated also explicitly for several predefined types of the interaction. To simplify the handling of the program, a short but very powerful notation has been introduced which help the user to deal with the two-particle states in various coupling notations. The main commands of the current version of the program are described in detail in Appendix B. Typical running time:The computation of all Moshinsky brackets in floating-point notation, up to ρ=6, takes about 5 s at a 2.26 GHz Intel Pentium IIII processor with 512 MB; in algebraic form, the same computations take about 13 s. Similarly, the computation of these brackets

  10. 0{nu}{beta}{beta}-decay nuclear matrix elements with self-consistent short-range correlations

    SciTech Connect

    Simkovic, Fedor; Faessler, Amand; Muether, Herbert; Rodin, Vadim; Stauf, Markus

    2009-05-15

    A self-consistent calculation of nuclear matrix elements of the neutrinoless double-beta decays (0{nu}{beta}{beta}) of {sup 76}Ge, {sup 82}Se, {sup 96}Zr, {sup 100}Mo, {sup 116}Cd, {sup 128}Te, {sup 130}Te, and {sup 136}Xe is presented in the framework of the renormalized quasiparticle random phase approximation (RQRPA) and the standard QRPA. The pairing and residual interactions as well as the two-nucleon short-range correlations are for the first time derived from the same modern realistic nucleon-nucleon potentials, namely, from the charge-dependent Bonn potential (CD-Bonn) and the Argonne V18 potential. In a comparison with the traditional approach of using the Miller-Spencer Jastrow correlations, matrix elements for the 0{nu}{beta}{beta} decay are obtained that are larger in magnitude. We analyze the differences among various two-nucleon correlations including those of the unitary correlation operator method (UCOM) and quantify the uncertainties in the calculated 0{nu}{beta}{beta}-decay matrix elements.

  11. Insights into Nuclear Triaxiality from Interference Effects in E2 Matrix Elements

    NASA Astrophysics Data System (ADS)

    Allmond, J. M.; Wood, J. L.; Kulp, W. D.

    2007-10-01

    Recently, we have introduced [1] a triaxial rotor model with independent inertia and E2 tensors. The E2 matrix elements [2] of the osmium isotopes (186, 188, 190, and 192) are studied in the framework of this model (59 of 84 E2 matrix elements deviate by 30% or less). It is shown that interference effects in the inertia tensor (K-mixing) and the E2 tensor can lead to significant reductions in the diagonal E2 matrix elements. In some instances, the diagonal E2 matrix elements may decrease with increasing spin. Additionally, a sum rule for diagonal E2 matrix elements is shown and used to explore missing strength from K-admixtures. [1] J.L. Wood, A-M. Oros-Peusquens, R. Zaballa, J.M. Allmond, and W.D. Kulp, Phys. Rev. C 70, 024308 (2004). [2] C.Y. Wu, D. Cline, T. Czosnyka, A. Backlin, C. Baktash, R.M. Diamond, G.D. Dracoulis, L. Hasselgren, H. Kluge, et al., Nucl. Phys. A607, 178 (1996).

  12. Quenched domain wall QCD with DBW2 gauge action toward nucleon decay matrix element calculation

    NASA Astrophysics Data System (ADS)

    Aoki, Yasumichi

    2001-10-01

    The domain wall fermion action is a promising way to control chiral symmetry in lattice gauge theory. By the good chiral symmetry of this approach even at finite lattice spacing, one is able to extract hadronic matrix elements, like kaon weak matrix elements, for which the symmetry is extremely important. Ordinary fermions with poor chiral symmetry make calculation difficult because of the large mixing of operators with different chiral structure. Even though the domain wall fermion action with the simple Wilson gauge action has a good chiral symmetry, one can further improve the symmetry by using a different gauge action. We take a non-perturbatively improved action, the DBW2 action of the QCD Taro group. Hadron masses are systematically examined for a range of parameters. Application to nucleon decay matrix element is also discussed.

  13. Constraining anomalous Higgs boson couplings to the heavy-flavor fermions using matrix element techniques

    NASA Astrophysics Data System (ADS)

    Gritsan, Andrei V.; Röntsch, Raoul; Schulze, Markus; Xiao, Meng

    2016-09-01

    In this paper, we investigate anomalous interactions of the Higgs boson with heavy fermions, employing shapes of kinematic distributions. We study the processes p p →t t ¯+H , b b ¯+H , t q +H , and p p →H →τ+τ- and present applications of event generation, reweighting techniques for fast simulation of anomalous couplings, as well as matrix element techniques for optimal sensitivity. We extend the matrix element likelihood approach (MELA) technique, which proved to be a powerful matrix element tool for Higgs boson discovery and characterization during Run I of the LHC, and implement all analysis tools in the JHU generator framework. A next-to-leading-order QCD description of the p p →t t ¯+H process allows us to investigate the performance of the MELA in the presence of extra radiation. Finally, projections for LHC measurements through the end of Run III are presented.

  14. Uncertainties in nuclear transition matrix elements of neutrinoless ββ decay

    SciTech Connect

    Rath, P. K.

    2013-12-30

    To estimate the uncertainties associated with the nuclear transition matrix elements M{sup (K)} (K=0ν/0N) for the 0{sup +} → 0{sup +} transitions of electron and positron emitting modes of the neutrinoless ββ decay, a statistical analysis has been performed by calculating sets of eight (twelve) different nuclear transition matrix elements M{sup (K)} in the PHFB model by employing four different parameterizations of a Hamiltonian with pairing plus multipolar effective two-body interaction and two (three) different parameterizations of Jastrow short range correlations. The averages in conjunction with their standard deviations provide an estimate of the uncertainties associated the nuclear transition matrix elements M{sup (K)} calculated within the PHFB model, the maximum of which turn out to be 13% and 19% owing to the exchange of light and heavy Majorana neutrinos, respectively.

  15. B(s) 0-mixing matrix elements from lattice QCD for the Standard Model and beyond

    NASA Astrophysics Data System (ADS)

    Bazavov, A.; Bernard, C.; Bouchard, C. M.; Chang, C. C.; DeTar, C.; Du, Daping; El-Khadra, A. X.; Freeland, E. D.; Gámiz, E.; Gottlieb, Steven; Heller, U. M.; Kronfeld, A. S.; Laiho, J.; Mackenzie, P. B.; Neil, E. T.; Simone, J.; Sugar, R.; Toussaint, D.; Van de Water, R. S.; Zhou, Ran; Fermilab Lattice; MILC Collaborations

    2016-06-01

    We calculate—for the first time in three-flavor lattice QCD—the hadronic matrix elements of all five local operators that contribute to neutral B0- and Bs-meson mixing in and beyond the Standard Model. We present a complete error budget for each matrix element and also provide the full set of correlations among the matrix elements. We also present the corresponding bag parameters and their correlations, as well as specific combinations of the mixing matrix elements that enter the expression for the neutral B -meson width difference. We obtain the most precise determination to date of the SU(3)-breaking ratio ξ =1.206 (18 )(6 ), where the second error stems from the omission of charm-sea quarks, while the first encompasses all other uncertainties. The threefold reduction in total uncertainty, relative to the 2013 Flavor Lattice Averaging Group results, tightens the constraint from B mixing on the Cabibbo-Kobayashi-Maskawa (CKM) unitarity triangle. Our calculation employs gauge-field ensembles generated by the MILC Collaboration with four lattice spacings and pion masses close to the physical value. We use the asqtad-improved staggered action for the light-valence quarks and the Fermilab method for the bottom quark. We use heavy-light meson chiral perturbation theory modified to include lattice-spacing effects to extrapolate the five matrix elements to the physical point. We combine our results with experimental measurements of the neutral B -meson oscillation frequencies to determine the CKM matrix elements |Vt d|=8.00 (34 )(8 )×10-3, |Vt s|=39.0 (1.2 )(0.4 )×10-3, and |Vt d/Vt s|=0.2052 (31 )(10 ), which differ from CKM-unitarity expectations by about 2 σ . These results and others from flavor-changing-neutral currents point towards an emerging tension between weak processes that are mediated at the loop and tree levels.

  16. Interface Cohesive Elements to Model Matrix Crack Evolution in Composite Laminates

    NASA Astrophysics Data System (ADS)

    Shi, Y.; Pinna, C.; Soutis, C.

    2014-02-01

    In this paper, the transverse matrix (resin) cracking developed in multidirectional composite laminates loaded in tension was numerically investigated by a finite element (FE) model implemented in the commercially available software Abaqus/Explicit 6.10. A theoretical solution using the equivalent constraint model (ECM) of the damaged laminate developed by Soutis et al. was employed to describe matrix cracking evolution and compared to the proposed numerical approach. In the numerical model, interface cohesive elements were inserted between neighbouring finite elements that run parallel to fibre orientation in each lamina to simulate matrix cracking with the assumption of equally spaced cracks (based on experimental measurements and observations). The stress based traction-separation law was introduced to simulate initiation of matrix cracking and propagation under mixed-mode loading. The numerically predicted crack density was found to depend on the mesh size of the model and the material fracture parameters defined for the cohesive elements. Numerical predictions of matrix crack density as a function of applied stress are in a good agreement to experimentally measured and theoretically (ECM) obtained values, but some further refinement will be required in near future work.

  17. Correlation functions of scattering matrix elements in microwave cavities with strong absorption

    NASA Astrophysics Data System (ADS)

    Schäfer, R.; Gorin, T.; Seligman, T. H.; Stöckmann, H.-J.

    2003-03-01

    The scattering matrix was measured for microwave cavities with two antennae. It was analysed in the regime of overlapping resonances. The theoretical description in terms of a statistical scattering matrix and the rescaled Breit-Wigner approximation has been applied to this regime. The experimental results for the auto-correlation function show that the absorption in the cavity walls yields an exponential decay. This behaviour can only be modelled using a large number of weakly coupled channels. In comparison to the auto-correlation functions, the cross-correlation functions of the diagonal S-matrix elements display a more pronounced difference between regular and chaotic systems.

  18. Calculation of radiative corrections to E1 matrix elements in the neutral alkali metals

    SciTech Connect

    Sapirstein, J.; Cheng, K.T.

    2005-02-01

    Radiative corrections to E1 matrix elements for ns-np transitions in the alkali-metal atoms lithium through francium are evaluated. They are found to be small for the lighter alkali metals but significantly larger for the heavier alkali metals, and in the case of cesium much larger than the experimental accuracy. The relation of the matrix element calculation to a recent decay rate calculation for hydrogenic ions is discussed, and application of the method to parity nonconservation in cesium is described.

  19. Generalization of the Mulliken-Hush treatment for the calculation of electron transfer matrix elements

    NASA Astrophysics Data System (ADS)

    Cave, Robert J.; Newton, Marshall D.

    1996-01-01

    A new method for the calculation of the electronic coupling matrix element for electron transfer processes is introduced and results for several systems are presented. The method can be applied to ground and excited state systems and can be used in cases where several states interact strongly. Within the set of states chosen it is a non-perturbative treatment, and can be implemented using quantities obtained solely in terms of the adiabatic states. Several applications based on quantum chemical calculations are briefly presented. Finally, since quantities for adiabatic states are the only input to the method, it can also be used with purely experimental data to estimate electron transfer matrix elements.

  20. Matrix elements for type 1 unitary irreducible representations of the Lie superalgebra gl(m|n)

    SciTech Connect

    Gould, Mark D.; Isaac, Phillip S.; Werry, Jason L.

    2014-01-15

    Using our recent results on eigenvalues of invariants associated to the Lie superalgebra gl(m|n), we use characteristic identities to derive explicit matrix element formulae for all gl(m|n) generators, particularly non-elementary generators, on finite dimensional type 1 unitary irreducible representations. We compare our results with existing works that deal with only subsets of the class of type 1 unitary representations, all of which only present explicit matrix elements for elementary generators. Our work therefore provides an important extension to existing methods, and thus highlights the strength of our techniques which exploit the characteristic identities.

  1. Hard photon production and matrix-element parton-shower merging

    SciTech Connect

    Hoeche, Stefan; Schumann, Steffen; Siegert, Frank

    2010-02-01

    We present a Monte Carlo approach to prompt-photon production, where photons and QCD partons are treated democratically. The photon fragmentation function is modeled by an interleaved QCD+QED parton shower. This known technique is improved by including higher-order real-emission matrix elements. To this end, we extend a recently proposed algorithm for merging matrix elements and truncated parton showers. We exemplify the quality of the Monte Carlo predictions by comparing them to measurements of the photon fragmentation function at LEP and to measurements of prompt photon and diphoton production from the Tevatron experiments.

  2. Phase space localization and matrix element distributions in systems with mixed classical phase space.

    PubMed

    Mehlig, B; Müller, K; Eckhardt, B

    1999-05-01

    We consider distributions of diagonal matrix elements for smooth observables in systems whose classical phase space has a mixture of chaotic and nearly integrable regions. The quantum distributions agree very well with distributions obtained from classical trajectory segments whose length is the Heisenberg time. Non-Gaussian wings in the distributions can be linked to classical trapping in certain parts of phase space, sometimes connected to islands, but also to regions separated by other barriers to transport. Thus classical deviations from ergodicity are quantitatively reflected in quantum matrix elements. The relation to scars is discussed.

  3. Analytic plastic potential for porous aggregates with matrix exhibiting tension-compression asymmetry

    NASA Astrophysics Data System (ADS)

    Cazacu, Oana; Stewart, Joel B.

    2009-02-01

    This paper is devoted to modeling the effects of the tension-compression asymmetry of the matrix on yielding of the void-matrix aggregate. The matrix plastic behavior is described by the Cazacu et al. [2006. Orthotropic yield criterion for hexagonal closed packed metals. Int. J. Plasticity 22, 1171-1194] isotropic yield criterion, which captures strength differential effects. Using an upper-bound approach, a new analytic isotropic plastic potential for a random distribution of spherical voids is obtained. The derived analytic potential is sensitive to the third invariant of the stress deviator and displays tension-compression asymmetry. In the case when the matrix material has the same yield in tension and compression, it reduces to Gurson's [1977. Continuum theory of ductile rupture by void nucleation and growth: Part I: Yield criteria and flow rules for porous ductile media. J. Eng. Mater. Technol. Trans. ASME Ser. H 99, 2-15.] criterion. Furthermore, the proposed criterion predicts the exact solution of a hollow sphere loaded in hydrostatic tension or compression. The accuracy of the proposed analytical criterion is assessed through comparisons with finite-element cell calculations.

  4. Investigation of Product Performance of Al-Metal Matrix Composites Brake Disc using Finite Element Analysis

    NASA Astrophysics Data System (ADS)

    Fatchurrohman, N.; Marini, C. D.; Suraya, S.; Iqbal, AKM Asif

    2016-02-01

    The increasing demand of fuel efficiency and light weight components in automobile sectors have led to the development of advanced material parts with improved performance. A specific class of MMCs which has gained a lot of attention due to its potential is aluminium metal matrix composites (Al-MMCs). Product performance investigation of Al- MMCs is presented in this article, where an Al-MMCs brake disc is analyzed using finite element analysis. The objective is to identify the potentiality of replacing the conventional iron brake disc with Al-MMCs brake disc. The simulation results suggested that the MMCs brake disc provided better thermal and mechanical performance as compared to the conventional cast iron brake disc. Although, the Al-MMCs brake disc dissipated higher maximum temperature compared to cast iron brake disc's maximum temperature. The Al-MMCs brake disc showed a well distributed temperature than the cast iron brake disc. The high temperature developed at the ring of the disc and heat was dissipated in circumferential direction. Moreover, better thermal dissipation and conduction at brake disc rotor surface played a major influence on the stress. As a comparison, the maximum stress and strain of Al-MMCs brake disc was lower than that induced on the cast iron brake disc.

  5. Comparative study and prediction of DNA fragments associated with various elements of the nuclear matrix.

    PubMed

    Glazko, G V; Rogozin, I B; Glazkov, M V

    2001-02-16

    Scaffold/matrix-associated region (S/MAR) sequences are DNA regions that are attached to the nuclear matrix, and participate in many cellular processes. The nuclear matrix is a complex structure consisting of various elements. In this paper we compared frequencies of simple nucleotide motifs in S/MAR sequences and in sequences extracted directly from various nuclear matrix elements, such as nuclear lamina, cores of rosette-like structures, synaptonemal complex. Multivariate linear discriminant analysis revealed significant differences between these sequences. Based on this result we have developed a program, ChrClass (Win/NT version, ftp.bionet.nsc.ru/pub/biology/chrclass/chrclass.zip), for the prediction of the regions associated with various elements of the nuclear matrix in a query sequence. Subsequently, several test samples were analyzed by using two S/MAR prediction programs (a ChrClass and MAR-Finder) and a simple MRS criterion (S/MAR recognition signature) indicating the presence of S/MARs. Some overlap between the predictions of all MAR prediction tools has been found. Simultaneous use of the ChrClass, MRS criterion and MAR-Finder programs may help to obtain a more clearcut picture of S/MAR distribution in a query sequence. In general, our results suggest that the proportion of missed S/MARs is lower for ChrClass, whereas the proportion of wrong S/MARs is lower for MAR-Finder and MRS.

  6. Numerical Modeling of Combined Matrix Cracking and Delamination in Composite Laminates Using Cohesive Elements

    NASA Astrophysics Data System (ADS)

    Kumar, Deepak; Roy, Rene; Kweon, Jin-Hwe; Choi, Jin-ho

    2016-06-01

    Sub-laminate damage in the form of matrix cracking and delamination was simulated by using interface cohesive elements in the finite element (FE) software ABAQUS. Interface cohesive elements were inserted parallel to the fiber orientation in the transverse ply with equal spacing (matrix cracking) and between the interfaces (delamination). Matrix cracking initiation in the cohesive elements was based on stress traction separation laws and propagated under mixed-mode loading. We expanded the work of Shi et al. (Appl. Compos. Mater. 21, 57-70 2014) to include delamination and simulated additional [45/-45/0/90]s and [02/90n]s { n = 1,2,3} CFRP laminates and a [0/903]s GFRP laminate. Delamination damage was quantified numerically in terms of damage dissipative energy. We observed that transverse matrix cracks can propagate to the ply interface and initiate delamination. We also observed for [0/90n/0] laminates that as the number of 90° ply increases past n = 2, the crack density decreases. The predicted crack density evolution compared well with experimental results and the equivalent constraint model (ECM) theory. Empirical relationships were established between crack density and applied stress by linear curve fitting. The reduction of laminate elastic modulus due to cracking was also computed numerically and it is in accordance with reported experimental measurements.

  7. Probing the many-body localization transition with matrix elements of local operators

    NASA Astrophysics Data System (ADS)

    Serbyn, Maksym; Papic, Zlatko; Abanin, Dmitry

    2015-03-01

    We propose the statistics of matrix elements of local operators as a new probe of the many-body localized (MBL) phase. Matrix elements of a given local operator V encode many physical properties, such as the response of the system to a local perturbation induced by the action of V, spectral functions, and dynamics of the system. The distribution of matrix elements of a local operator between system's eigenstates exhibits qualitatively different behavior in the many-body localized and ergodic phases, allowing for an accurate determination of the two phases. To characterize this distribution, for a given system size L, we introduce a parameter g (L) = < log Vi,i+1/Δ >, which is a disorder-averaged ratio of the matrix element of operator V between adjacent eigenstates, and Δ is the level spacing. We find that g (L) decreases with L in the MBL phase, and grows in the ergodic phase. We propose that at the MBL-delocalization transition g (L) is independent of system size, g (L) =gc ~ 1 , and use this criterion to map out the phase diagram of a disordered 1D XXZ spin-1/2 chain. By studying the scaling of g (L) as a function of energy density, we locate the many-body mobility edge. We discuss implications for delocalization phase transition.

  8. Potential of Organic Matrix Composites for Liquid Oxygen Tank

    NASA Technical Reports Server (NTRS)

    Davis, Samuel E.; Herald, Stephen D.; Stolzfus, Joel M.; Engel, Carl D.; Bohlen, James W.; Palm, Tod; Robinson, Michael J.

    2005-01-01

    Composite materials are being considered for the tankage of cryogenic propellants in access to space because of potentially lower structural weights. A major hurdle for composites is an inherent concern about the safety of using flammable structural materials in contact with liquid and gaseous oxygen. A hazards analysis approach addresses a series of specific concerns that must be addressed based upon test data. Under the 2nd Generation Reusable Launch Vehicle contracts, testing was begun for a variety of organic matrix composite materials both to aid in the selection of materials and to provide needed test data to support hazards analyses. The work has continued at NASA MSFC and the NASA WSTF to provide information on the potential for using composite materials in oxygen systems. Appropriate methods for oxygen compatibility testing of structural materials and data for a range of composite materials from impact, friction, flammability and electrostatic discharge testing are presented. Remaining concerns and conclusions about composite tank structures, and recommendations for additional testing are discussed. Requirements for system specific hazards analysis are identified.

  9. [Regulatory potential of S/MAR elements in transient expression].

    PubMed

    Sass, A V; Ruda, V M; Akopov, S B; Snezhkov, E V; Nikolaev, L G; Sverdlov, E D

    2005-01-01

    S/MARs (scaffold/matrix attachment regions) are the DNA regions that are involved in the interaction with the nuclear matrix and are identified by in vitro methods. According to the available information, S/MARs possess an insulating activity, i.e., the ability to block the interaction between the enhancer and promoter in vivo, and are, probably, intact insulators or their fragments. Nevertheless, there is still no direct proof for this correspondence. To obtain additional information on the insulator activity of S/MARs, we selected five DNA fragments of different lengths and affinities for the nuclear matrix from the previously constructed library of S/MARs and tested their ability to serve as insulators. Two of five elements exhibited an insulator (enhancer-blocking) activity upon the transient transfection of CHO cells. None of the S/MARs displayed either promoter or enhancer/silencer activities in these cells. PMID:15787217

  10. Matrix-Assisted Plasma Atomization Emission Spectrometry for Surface Sampling Elemental Analysis

    PubMed Central

    Yuan, Xin; Zhan, Xuefang; Li, Xuemei; Zhao, Zhongjun; Duan, Yixiang

    2016-01-01

    An innovative technology has been developed involving a simple and sensitive optical spectrometric method termed matrix-assisted plasma atomization emission spectrometry (MAPAES) for surface sampling elemental analysis using a piece of filter paper (FP) for sample introduction. MAPAES was carried out by direct interaction of the plasma tail plume with the matrix surface. The FP absorbs energy from the plasma source and releases combustion heating to the analytes originally present on its surface, thus to promote the atomization and excitation process. The matrix-assisted plasma atomization excitation phenomenon was observed for multiple elements. The FP matrix served as the partial energy producer and also the sample substrate to adsorb sample solution. Qualitative and quantitative determinations of metal ions were achieved by atomic emission measurements for elements Ba, Cu, Eu, In, Mn, Ni, Rh and Y. The detection limits were down to pg level with linear correlation coefficients better than 0.99. The proposed MAPAES provides a new way for atomic spectrometry which offers advantages of fast analysis speed, little sample consumption, less sample pretreatment, small size, and cost-effective. PMID:26762972

  11. Matrix-Assisted Plasma Atomization Emission Spectrometry for Surface Sampling Elemental Analysis

    NASA Astrophysics Data System (ADS)

    Yuan, Xin; Zhan, Xuefang; Li, Xuemei; Zhao, Zhongjun; Duan, Yixiang

    2016-01-01

    An innovative technology has been developed involving a simple and sensitive optical spectrometric method termed matrix-assisted plasma atomization emission spectrometry (MAPAES) for surface sampling elemental analysis using a piece of filter paper (FP) for sample introduction. MAPAES was carried out by direct interaction of the plasma tail plume with the matrix surface. The FP absorbs energy from the plasma source and releases combustion heating to the analytes originally present on its surface, thus to promote the atomization and excitation process. The matrix-assisted plasma atomization excitation phenomenon was observed for multiple elements. The FP matrix served as the partial energy producer and also the sample substrate to adsorb sample solution. Qualitative and quantitative determinations of metal ions were achieved by atomic emission measurements for elements Ba, Cu, Eu, In, Mn, Ni, Rh and Y. The detection limits were down to pg level with linear correlation coefficients better than 0.99. The proposed MAPAES provides a new way for atomic spectrometry which offers advantages of fast analysis speed, little sample consumption, less sample pretreatment, small size, and cost-effective.

  12. Matrix-Assisted Plasma Atomization Emission Spectrometry for Surface Sampling Elemental Analysis.

    PubMed

    Yuan, Xin; Zhan, Xuefang; Li, Xuemei; Zhao, Zhongjun; Duan, Yixiang

    2016-01-01

    An innovative technology has been developed involving a simple and sensitive optical spectrometric method termed matrix-assisted plasma atomization emission spectrometry (MAPAES) for surface sampling elemental analysis using a piece of filter paper (FP) for sample introduction. MAPAES was carried out by direct interaction of the plasma tail plume with the matrix surface. The FP absorbs energy from the plasma source and releases combustion heating to the analytes originally present on its surface, thus to promote the atomization and excitation process. The matrix-assisted plasma atomization excitation phenomenon was observed for multiple elements. The FP matrix served as the partial energy producer and also the sample substrate to adsorb sample solution. Qualitative and quantitative determinations of metal ions were achieved by atomic emission measurements for elements Ba, Cu, Eu, In, Mn, Ni, Rh and Y. The detection limits were down to pg level with linear correlation coefficients better than 0.99. The proposed MAPAES provides a new way for atomic spectrometry which offers advantages of fast analysis speed, little sample consumption, less sample pretreatment, small size, and cost-effective. PMID:26762972

  13. $$B^0_{(s)}$$-mixing matrix elements from lattice QCD for the Standard Model and beyond

    DOE PAGES

    Bazavov, A.; Bernard, C.; Bouchard, C. M.; Chang, C. C.; DeTar, C.; Du, Daping; El-Khadra, A. X.; Freeland, E. D.; Gamiz, E.; Gottlieb, Steven; et al

    2016-06-28

    We calculate—for the first time in three-flavor lattice QCD—the hadronic matrix elements of all five local operators that contribute to neutral B0- and Bs-meson mixing in and beyond the Standard Model. We present a complete error budget for each matrix element and also provide the full set of correlations among the matrix elements. We also present the corresponding bag parameters and their correlations, as well as specific combinations of the mixing matrix elements that enter the expression for the neutral B-meson width difference. We obtain the most precise determination to date of the SU(3)-breaking ratio ξ=1.206(18)(6), where the second errormore » stems from the omission of charm-sea quarks, while the first encompasses all other uncertainties. The threefold reduction in total uncertainty, relative to the 2013 Flavor Lattice Averaging Group results, tightens the constraint from B mixing on the Cabibbo-Kobayashi-Maskawa (CKM) unitarity triangle. Our calculation employs gauge-field ensembles generated by the MILC Collaboration with four lattice spacings and pion masses close to the physical value. We use the asqtad-improved staggered action for the light-valence quarks and the Fermilab method for the bottom quark. We use heavy-light meson chiral perturbation theory modified to include lattice-spacing effects to extrapolate the five matrix elements to the physical point. We combine our results with experimental measurements of the neutral B-meson oscillation frequencies to determine the CKM matrix elements |Vtd| = 8.00(34)(8)×10-3, |Vts| = 39.0(1.2)(0.4)×10-3, and |Vtd/Vts| = 0.2052(31)(10), which differ from CKM-unitarity expectations by about 2σ. In addition, these results and others from flavor-changing-neutral currents point towards an emerging tension between weak processes that are mediated at the loop and tree levels.« less

  14. Study of matrix crack-tilted fiber bundle interaction using caustics and finite element method.

    PubMed

    Hao, Wenfeng; Zhu, Jianguo; Zhu, Qi; Yuan, Yanan

    2016-02-01

    In this work, the interaction between the matrix crack and a tilted fiber bundle was investigated via caustics and the finite element method (FEM). First, the caustic patterns at the crack tip with different distances from the tilted fiber were obtained and the stress intensity factors were extracted from the geometry of the caustic patterns. Subsequently, the shielding effect of the fiber bundle in front of the crack tip was analyzed. Furthermore, the interaction between the matrix crack and the broken fiber bundle was discussed. Finally, a finite element simulation was carried out using ABAQUS to verify the experimental results. The results demonstrate that the stress intensity factors extracted from caustic experiments are in excellent agreement with the data calculated by FEM. PMID:26931836

  15. Study of matrix crack-tilted fiber bundle interaction using caustics and finite element method

    NASA Astrophysics Data System (ADS)

    Hao, Wenfeng; Zhu, Jianguo; Zhu, Qi; Yuan, Yanan

    2016-02-01

    In this work, the interaction between the matrix crack and a tilted fiber bundle was investigated via caustics and the finite element method (FEM). First, the caustic patterns at the crack tip with different distances from the tilted fiber were obtained and the stress intensity factors were extracted from the geometry of the caustic patterns. Subsequently, the shielding effect of the fiber bundle in front of the crack tip was analyzed. Furthermore, the interaction between the matrix crack and the broken fiber bundle was discussed. Finally, a finite element simulation was carried out using ABAQUS to verify the experimental results. The results demonstrate that the stress intensity factors extracted from caustic experiments are in excellent agreement with the data calculated by FEM.

  16. Calculation of reflection matrix elements of a grating for growing evanescent waves.

    SciTech Connect

    Kumar, V.; Kim, K.-J.; Accelerator Systems Division

    2006-01-01

    Reflection matrix elements of a grating play an important role in the study of Smith-Purcell (SP) free-electron lasers (FELs). Especially, the matrix element R00, which couples the incident co-propagating evanescent wave to the reflected co-propagating evanescent wave, is important for evaluation of the gain of an SP-FEL system [1]. We present a calculation of R00for rectangular grating and study its frequency dependence for a given phase velocity of incident wave. For the numerical calculation, we use the modal expansion method and extend it to include waves having slowly varying amplitude. The singularity of R00is studied in some detail and we find that it is possible to get a simple formula for the location of the singularity if we choose the eigenmodes of the groove as a basis set as done by Andrews et al. [2].

  17. Shell-model analysis of the 136Xe double beta decay nuclear matrix elements.

    PubMed

    Horoi, M; Brown, B A

    2013-05-31

    Neutrinoless double beta decay, if observed, could distinguish whether the neutrino is a Dirac or a Majorana particle, and it could be used to determine the absolute scale of the neutrino masses. 136Xe is one of the most promising candidates for observing this rare event. However, until recently there were no positive results for the allowed and less rare two-neutrino double beta decay mode. The small nuclear matrix element associated with the long half-life represents a challenge for nuclear structure models used for its calculation. We report a new shell-model analysis of the two-neutrino double beta decay of 136Xe, which takes into account all relevant nuclear orbitals necessary to fully describe the associated Gamow-Teller strength. We further use the new model to analyze the main contributions to the neutrinoless double beta decay matrix element, and show that they are also diminished.

  18. Nuclear matrix elements for 0{nu}{beta}{beta} decay with improved short-range correlations

    SciTech Connect

    Kortelainen, M.; Suhonen, J.

    2007-10-12

    Nuclear matrix elements for the neutrinoless double beta minus (0{nu}{beta}{sup -}{beta}{sup -}) decays of all interesting (nearly) spherical nuclei are calculated for the light-neutrino exchange mechanism by using the proton-neutron quasiparticle random-phase approximation (pnQRPA) with a realistic nucleon-nucleon force. The finite size of a nucleon, the higher-order terms of nucleonic weak currents, and the nucleon-nucleon short-range correlations (s.r.c) are taken into account. The s.r.c. are computed by the use of the unitary correlation operator method (UCOM), superior to the traditional Jastrow method. The UCOM computed matrix elements turn out to be considerably larger than the Jastrow computed ones.

  19. Short-distance matrix elements for $D$-meson mixing for 2+1 lattice QCD

    SciTech Connect

    Chang, Chia Cheng

    2015-01-01

    We study the short-distance hadronic matrix elements for D-meson mixing with partially quenched Nf = 2+1 lattice QCD. We use a large set of the MIMD Lattice Computation Collaboration's gauge configurations with a2 tadpole-improved staggered sea quarks and tadpole-improved Lüscher-Weisz gluons. We use the a2 tadpole-improved action for valence light quarks and the Sheikoleslami-Wohlert action with the Fermilab interpretation for the valence charm quark. Our calculation covers the complete set of five operators needed to constrain new physics models for D-meson mixing. We match our matrix elements to the MS-NDR scheme evaluated at 3 GeV. We report values for the Beneke-Buchalla-Greub-Lenz-Nierste choice of evanescent operators.

  20. Addressable test matrix for measuring analog transfer characteristics of test elements used for integrated process control and device evaluation

    NASA Technical Reports Server (NTRS)

    Buehler, Martin G. (Inventor)

    1988-01-01

    A set of addressable test structures, each of which uses addressing schemes to access individual elements of the structure in a matrix, is used to test the quality of a wafer before integrated circuits produced thereon are diced, packaged and subjected to final testing. The electrical characteristic of each element is checked and compared to the electrical characteristic of all other like elements in the matrix. The effectiveness of the addressable test matrix is in readily analyzing the electrical characteristics of the test elements and in providing diagnostic information.

  1. Lidar investigations of hydrosols: notes on the determination of scattering matrix elements.

    PubMed

    Reuter, R

    1982-10-15

    The feasibility of lidar remote sensing of marine particulate matter is discussed. An evaluation of the elements of the scattering matrix requires a bistatic configuration of the instrument. The influence of the rough water surface transmission on the lidar signal is investigated. It is shown that, when using circular polarized laser light, two signals can be obtained without interference of the surface waves. These signals render characteristic signatures concerning the nature of hydrosols.

  2. Useful extremum principle for the variational calculation of matrix elements. II

    NASA Technical Reports Server (NTRS)

    Gerjuoy, E.; Rosenberg, L.; Spruch, L.

    1975-01-01

    Recent work (Gerjuoy et al., 1974) on variational principles for diagonal bound state matrix elements of arbitrary Hermitian operators is extended. In particular, it is shown that the previously derived minimum principle for the trial auxiliary function appearing in such variational principles can be constructed using a modified Hamiltonian possessing not heretofore recognized positive definite properties. Thus there is at least one alternative to the particular modified Hamiltonian on which the results of Gerjuoy et al. (1974) originally were based.

  3. An improved method for extracting matrix elements from lattice three-point functions

    SciTech Connect

    C. Aubin, K. Orginos

    2011-12-01

    The extraction of matrix elements from baryon three-point functions is complicated by the fact that the signal-to-noise drops rapidly as a function of time. Using a previously discussed method to improve the signal-to-noise for lattice two-point functions, we use this technique to do so for lattice three-point functions, using electromagnetic form factors for the nucleon and Delta as an example.

  4. Urinary stones as a novel matrix for human biomonitoring of toxic and essential elements.

    PubMed

    Kuta, J; Smetanová, S; Benová, D; Kořistková, T; Machát, J

    2016-02-01

    Monitoring of body burden of toxic elements is usually based on analysis of concentration of particular elements in blood, urine and/or hair. Analysis of these matrices, however, predominantly reflects short- or medium-term exposure to trace elements or pollutants. In this work, urinary stones were investigated as a matrix for monitoring long-term exposure to toxic and essential elements. A total of 431 samples of urinary calculi were subjected to mineralogical and elemental analysis by infrared spectroscopy and inductively coupled plasma mass spectrometry. The effect of mineralogical composition of the stones and other parameters such as sex, age and geographical location on contents of trace and minor elements is presented. Our results demonstrate the applicability of such approach and confirm that the analysis of urinary calculi can be helpful in providing complementary information on human exposure to trace metals and their excretion. Analysis of whewellite stones (calcium oxalate monohydrate) with content of phosphorus <0.6 % has been proved to be a promising tool for biomonitoring of trace and minor elements.

  5. Quantum pumping by a moving modulated potential and finite matrix methods

    NASA Astrophysics Data System (ADS)

    Corvino, Frank A.

    Quantum pumping holds great potential for future applications in micro- and nanotechnology. Its main feature, dissipationless charge transport, is theoretically possible via several different mechanisms. Here we study quantum pumping in a one dimensional electron waveguide with a single time-dependent barrier. The quantum pumping of electrons using a potential barrier whose height and position are harmonically varied is analyzed analytically and by numerically solving the time-dependent Schrodinger equation. The pumped charge is modeled analytically by including two contributions in linear response theory. First, the scattering of electrons off a potential moving slowly through matter-waves gives a contribution independent of the translational velocity of the potential. Second, Doppler-shifted scattering events give rise to a velocity dependent contribution, which is found in general to be small in comparison with the first one. The relative phase between the oscillations of the height and position is found to be the factor that determines to what extent either contribution is present. We also test the recently developed Generalized Moments Expansion,GMX( n,m) where, associated with each matrix element, there is a unique expansion for the ground state energy in terms of the connected moments Ik of the Hamiltonian. Here we wish to study the eigenvectors and eigenvalues of the GMX matrix itself. Furthermore we investigate the interplay between the set {n,m} and the order L of the matrix in determining which combination {n,m,L} yields the best" (i.e. most convergent) result for the ground state energy for two. Here we apply the above GMX-matrix formalism to two well-known Hamiltonian systems in quantum chemistry. The first model Hamiltonian is that which describes a set of N one-dimensional oscillators. A second (and related) model Hamiltonian system is the Pullen-Edmonds Hamiltonian which describes a two-dimensional anharmonic oscillator. In another application of

  6. A Data Matrix Method for Improving the Quantification of Element Percentages of SEM/EDX Analysis

    NASA Technical Reports Server (NTRS)

    Lane, John

    2009-01-01

    A simple 2D M N matrix involving sample preparation enables the microanalyst to peer below the noise floor of element percentages reported by the SEM/EDX (scanning electron microscopy/ energy dispersive x-ray) analysis, thus yielding more meaningful data. Using the example of a 2 3 sample set, there are M = 2 concentration levels of the original mix under test: 10 percent ilmenite (90 percent silica) and 20 percent ilmenite (80 percent silica). For each of these M samples, N = 3 separate SEM/EDX samples were drawn. In this test, ilmenite is the element of interest. By plotting the linear trend of the M sample s known concentration versus the average of the N samples, a much higher resolution of elemental analysis can be performed. The resulting trend also shows how the noise is affecting the data, and at what point (of smaller concentrations) is it impractical to try to extract any further useful data.

  7. Evaluation of Solid Modeling Software for Finite Element Analysis of Woven Ceramic Matrix Composites

    NASA Technical Reports Server (NTRS)

    Nemeth, Noel N.; Mital, Subodh; Lang, Jerry

    2010-01-01

    Three computer programs, used for the purpose of generating 3-D finite element models of the Repeating Unit Cell (RUC) of a textile, were examined for suitability to model woven Ceramic Matrix Composites (CMCs). The programs evaluated were the open-source available TexGen, the commercially available WiseTex, and the proprietary Composite Material Evaluator (COMATE). A five-harness-satin (5HS) weave for a melt-infiltrated (MI) silicon carbide matrix and silicon carbide fiber was selected as an example problem and the programs were tested for their ability to generate a finite element model of the RUC. The programs were also evaluated for ease-of-use and capability, particularly for the capability to introduce various defect types such as porosity, ply shifting, and nesting of a laminate. Overall, it was found that TexGen and WiseTex were useful for generating solid models of the tow geometry; however, there was a lack of consistency in generating well-conditioned finite element meshes of the tows and matrix. TexGen and WiseTex were both capable of allowing collective and individual shifting of tows within a ply and WiseTex also had a ply nesting capability. TexGen and WiseTex were sufficiently userfriendly and both included a Graphical User Interface (GUI). COMATE was satisfactory in generating a 5HS finite element mesh of an idealized weave geometry but COMATE lacked a GUI and was limited to only 5HS and 8HS weaves compared to the larger amount of weave selections available with TexGen and WiseTex.

  8. On the possibility to measure 0{nu}{beta}{beta}-decay nuclear matrix element for {sup 48}Ca

    SciTech Connect

    Rodin, Vadim

    2011-12-16

    As shown in Ref. [2], the Fermi part M{sub F}{sup 0{nu}} of the total 0{nu}{beta}{beta}-decay nuclear matrix element M{sup 0{nu}} can be related to the single Fermi transition matrix element between the isobaric analog state (IAS) of the ground state of the initial nucleus and the ground state of the final nucleus. The latter matrix element could be measured in charge-exchange reactions. Here we discuss a possibility of such a measurement for {sup 48}Ca and estimate the cross-section of the reaction {sup 48}Ti(n,p){sup 48}Sc(IAS).

  9. Model independent analysis of gluonic pole matrix elements and universality of transverse-momentum-dependent fragmentation functions

    SciTech Connect

    Gamberg, L. P.; Mukherjee, A.; Mulders, P. J.

    2011-04-01

    Gluonic pole matrix elements explain the appearance of single spin asymmetries (SSA) in high-energy scattering processes. They involve a combination of operators which are odd under time reversal (T-odd). Such matrix elements appear in principle both for parton distribution functions and parton fragmentation functions. We show that for parton fragmentation functions, these gluonic pole matrix elements vanish as a consequence of the analytic structure of scattering amplitudes in quantum chromodynamics. This result is important in the study of the universality of transverse-momentum-dependent (TMD) fragmentation functions.

  10. A triangular element based on generalized potential energy concepts

    NASA Technical Reports Server (NTRS)

    Thomas, G. R.; Gallagher, R. H.

    1976-01-01

    Stiffness equations are formulated for a doubly-curved triangular thin shell finite element. The strain energy component of the potential energy is first expressed in terms of displacements and displacement gradients with the aid of consistent deep shell strain-displacement equations. The element in-plane and normal displacement fields are approximated by complete cubic polynomials. These functions do not satisfy the interelement displacement admissibility conditions. Satisfaction is forced by the imposition of constraint conditions on the interelement boundaries; the constraints represent the modification of the potential energy. Some numerical results for a pinched cylinder, a cylindrical sphere, and a pinched sphere are examined.

  11. Experimental studies of nuclear matrix elements for neutrino-less ββ decays

    SciTech Connect

    Ejiri, H.

    2013-12-30

    Nuclear matrix elements M{sup 0ν} for neutrino less double beta decays (0νββ) are crucial for neutrino studies in 0νββ experiments. The neutrino mass to be studied is sensitive to M{sup 0ν}, while theoretical calculations for M{sup 0ν} are hard. Thus experimental studies of nuclear structures and single β matrix elements M{sub β} associated with 0νββ are useful to confirm and help the theoretical calculations. This reports briefly experimental methods and recent charge exchange reaction studies for M{sub β}. The single β elements for M{sup ±}(2{sup −}) associated with M{sup 0ν}(2{sup −}), which is the major component of M{sup 0ν}, are found to be reduced (quenched) much by the spin isospin correlation and the nuclear medium (non-nucleonic isobar) effect. The present result suggests that the spin isospin components of M{sup 0ν} is fairly reduced (quenched)

  12. On- and off-resonance radiation-atom-coupling matrix elements involving extended atomic wave functions

    NASA Astrophysics Data System (ADS)

    Komninos, Yannis; Mercouris, Theodoros; Nicolaides, Cleanthes A.

    2014-01-01

    In continuation of our earlier works, we present results concerning the computation of matrix elements of the multipolar Hamiltonian (MPH) between extended wave functions that are obtained numerically. The choice of the MPH is discussed in connection with the broader issue of the form of radiation-atom (or -molecule) interaction that is appropriate for the systematic solution of various problems of matter-radiation interaction. We derive analytic formulas, in terms of the sine-integral function and spherical Bessel functions of various orders, for the cumulative radial integrals that were obtained and calculated by Komninos, Mercouris, and Nicolaides [Phys. Rev. A 71, 023410 (2005), 10.1103/PhysRevA.71.023410]. This development allows the much faster and more accurate computation of such matrix elements, a fact that enhances the efficiency with which the time-dependent Schrödinger equation is solved nonperturbatively, in the framework of the state-specific expansion approach. The formulas are applicable to the general case where a pair of orbitals with angular parts |ℓ1,m1> and |ℓ2,m2> are coupled radiatively. As a test case, we calculate the matrix elements of the electric field and of the paramagnetic operators for on- and off-resonance transitions, between hydrogenic circular states of high angular momentum, whose quantum numbers are chosen so as to satisfy electric dipole and electric quadrupole selection rules. Because of the nature of their wave function (they are nodeless and the large centrifugal barrier keeps their overwhelming part at large distances from the nucleus), the validity of the electric dipole approximation in various applications where the off-resonance couplings must be considered becomes precarious. For example, for the transition from the circular state with n = 20 to that with n = 21, for which ≈400 a.u., the dipole approximation starts to fail already at XUV wavelengths (λ <125nm).

  13. Potential energy landscapes of elemental and heterogeneous chalcogen clusters

    SciTech Connect

    Mauro, John C.; Loucks, Roger J.; Balakrishnan, Jitendra; Varshneya, Arun K.

    2006-02-15

    We describe the potential energy landscapes of elemental S{sub 8}, Se{sub 8}, and Te{sub 8} clusters using disconnectivity graphs. Inherent structures include both ring and chain configurations, with rings especially dominant in Se{sub 8}. We also map the potential energy landscapes of heterogeneous Se{sub n}(S,Te){sub 8-n} clusters, which offer insights into the structure of heterogeneous chalcogen glasses.

  14. Spanwise variation of potential form drag. [finite element method

    NASA Technical Reports Server (NTRS)

    Clever, W. C.

    1977-01-01

    The finite element method is used to calculate the spanwise variation of potential form drag of a wing at subsonic and supersonic speeds using linearly varying panels. The wing may be of arbitrary planform and nonplanar provided the wing panels are parallel to the aircraft axis.

  15. Electron-H2 Collisions Studied Using the Finite Element Z-Matrix Method

    NASA Technical Reports Server (NTRS)

    Huo, Winifred M.; Brown, David; Langhoff, Stephen R. (Technical Monitor)

    1997-01-01

    We have applied the Z-matrix method, using a mixed basis of finite elements and Gaussians, to study e-H2 elastic and inelastic collisions. Special attention is paid to the quality of the basis set and the treatment of electron correlation. The calculated cross sections are invariant, to machine accuracy, with respect to the choice of parameters a, b, d, e as long as they satisfy Equation (3). However, the log derivative approach, i.e., the choice a = -e = 1, b = d = 0 appears to converge slightly faster than other choices. The cross sections agree well with previous theoretical results. Comparison will be made with available experimental data.

  16. Shape and pairing fluctuation effects on neutrinoless double beta decay nuclear matrix elements.

    PubMed

    López Vaquero, Nuria; Rodríguez, Tomás R; Egido, J Luis

    2013-10-01

    Nuclear matrix elements (NME) for the most promising candidates to detect neutrinoless double beta decay have been computed with energy density functional methods including deformation and pairing fluctuations explicitly on the same footing. The method preserves particle number and angular momentum symmetries and can be applied to any decay without additional fine tunings. The finite range density dependent Gogny force is used in the calculations. An increase of 10%-40% in the NME with respect to the ones found without the inclusion of pairing fluctuations is obtained, reducing the predicted half-lives of these isotopes.

  17. Many-body correlations of QRPA in nuclear matrix elements of double-beta decay

    SciTech Connect

    Terasaki, J.

    2015-10-28

    We present two new ideas on the quasiparticle random-phase approximation (QRPA) approach for calculating nuclear matrix elements of double-beta decay. First, it is necessary to calculate overlaps of the QRPA states obtained on the basis of the ground states of different nuclei. We calculate this overlap using quasiboson vacua as the QRPA ground states. Second, we show that two-particle transfer paths are possible to use for the calculation under the closure approximation. A calculation is shown for {sup 150}Nd→{sup 150}Sm using these two new ideas, and their implication is discussed.

  18. Nuclear matrix elements from direct lifetime or cross-section measurements

    SciTech Connect

    Werner, V.; Cooper, N.; Hinton, M.; Ilie, G.; Radeck, D.

    2012-11-20

    The method of simultaneous lifetime and g factor measurements using a plunger device and the RDDS and TDRIV techniques is introduced. Results on lifetimes and hyperfine-interaction parameters for 2{sup +}{sub 1} states in {sup 104-108}Pd, {sup 96,98,104}Ru, and {sup 92,94}Zr, using a plunger device. Another method to obtain electromagnetic matrix elements is direct cross section measurements using NRF. The method is outlined, and some recent results on {sup 76}Se are shown.

  19. Differential cross sections and spin density matrix elements for the reaction gamma p -> p omega

    SciTech Connect

    M. Williams, D. Applegate, M. Bellis, C.A. Meyer

    2009-12-01

    High-statistics differential cross sections and spin density matrix elements for the reaction gamma p -> p omega have been measured using the CLAS at Jefferson Lab for center-of-mass (CM) energies from threshold up to 2.84 GeV. Results are reported in 112 10-MeV wide CM energy bins, each subdivided into cos(theta_CM) bins of width 0.1. These are the most precise and extensive omega photoproduction measurements to date. A number of prominent structures are clearly present in the data. Many of these have not previously been observed due to limited statistics in earlier measurements.

  20. Derivation of a general expression for the momentum matrix elements within the envelope-function approximation

    NASA Astrophysics Data System (ADS)

    Szmulowicz, Frank

    1995-01-01

    A general expression for the momentum matrix elements for both intrasubband and intersubband transitions in n- or p-type doped quantum wells, wires, and dots is derived within the envelope-function approximation, in the process unifying the description of optical absorption in n- and p-type heterostructures. The derivation is nontrivially extended to the case of wave-function penetration into the barrier in a way that satisfies the principle of microscopic reversibility. The contribution of the valence-band anisotropy is shown to contribute to normal-incidence absorption in p-type heterostructures.

  1. An accurate quantum expression of the z-dipole matrix element between nearby Rydberg parabolic states and the correspondence principle

    NASA Astrophysics Data System (ADS)

    Dewangan, D. P.

    2008-01-01

    We give an exact quantum formula for the z-component of the dipole matrix element between parabolic states of a hydrogen atom in terms of the Jacobi polynomials. The formula extends the range of numerical computation to larger values of the parabolic quantum numbers for which computation from the standard textbook formula, which is in terms of the hypergeometric functions, is defined. We obtain an accurate quantum expression of the z-dipole matrix element in terms of the ordinary Bessel functions for transition between nearby Rydberg parabolic states. We derive for the first time the formula of the z-dipole matrix element of the correspondence principle method directly from the quantum expression, and in the process of derivation, clarify the nature of classical-quantum correspondence. The expressions obtained in this work solve the problem of computation of the z-dipole matrix element of hydrogen to a large extent.

  2. A hybrid finite element-transfer matrix model for vibroacoustic systems with flat and homogeneous acoustic treatments.

    PubMed

    Alimonti, Luca; Atalla, Noureddine; Berry, Alain; Sgard, Franck

    2015-02-01

    Practical vibroacoustic systems involve passive acoustic treatments consisting of highly dissipative media such as poroelastic materials. The numerical modeling of such systems at low to mid frequencies typically relies on substructuring methodologies based on finite element models. Namely, the master subsystems (i.e., structural and acoustic domains) are described by a finite set of uncoupled modes, whereas condensation procedures are typically preferred for the acoustic treatments. However, although accurate, such methodology is computationally expensive when real life applications are considered. A potential reduction of the computational burden could be obtained by approximating the effect of the acoustic treatment on the master subsystems without introducing physical degrees of freedom. To do that, the treatment has to be assumed homogeneous, flat, and of infinite lateral extent. Under these hypotheses, simple analytical tools like the transfer matrix method can be employed. In this paper, a hybrid finite element-transfer matrix methodology is proposed. The impact of the limiting assumptions inherent within the analytical framework are assessed for the case of plate-cavity systems involving flat and homogeneous acoustic treatments. The results prove that the hybrid model can capture the qualitative behavior of the vibroacoustic system while reducing the computational effort.

  3. Multipole operators in semileptonic weak and electromagnetic interactions with nuclei. II. General single-particle matrix elements

    SciTech Connect

    Donnelly, T.W.; Haxton, W.C.

    1980-01-01

    We extend our previous harmonic oscillator analysis to a treatment of general single-particle matrix elements of the multipole operators arising in studies of semileptonic weak and electromagnetic interactions with nuclei. Together with the earlier harmonic oscillator tables the present work will allow the reader to express these general matrix elements compactly in terms of specific radial integrals, which then usually must be evaluated numerically.

  4. Measurement of the top quark mass in the lepton+jets final state with the matrix element method

    SciTech Connect

    Abazov, V.M.; Abbott, B.; Abolins, M.; Acharya, B.S.; Adams, M.; Adams, T.; Agelou, M.; Aguilo, E.; Ahn, S.H.; Ahsan, M.; Alexeev, G.D.; /Buenos Aires U. /Rio de Janeiro, CBPF /Sao Paulo, IFT /Alberta U. /Simon Fraser U. /York U., Canada /McGill U. /Hefei, CUST /Andes U., Bogota /Charles U. /Prague, Tech. U.

    2006-09-01

    We present a measurement of the top quark mass with the Matrix Element method in the lepton+jets final state. As the energy scale for calorimeter jets represents the dominant source of systematic uncertainty, the Matrix Element likelihood is extended by an additional parameter, which is defined as a global multiplicative factor applied to the standard energy scale. The top quark mass is obtained from a fit that yields the combined statistical and systematic jet energy scale uncertainty.

  5. Comparative Study of Various Algorithms for the Merging of Parton Showers and Matrix Elements in Hadronic Collisions

    SciTech Connect

    Alwall, J.; Hoche, S.; Krauss, F.; Lavesson, N.; Lonnblad, L.; Maltoni, F.; Mangano, M.L.; Moretti, M.; Papadopoulos, C.G.; Piccinini, F.; Schumann, S.; Treccani, M.; Winter, J.; Worek, M.; /SLAC /Durham U., IPPP /Lund U. /Louvain U. /CERN /Ferrara U. /INFN, Ferrara /Athens U. /INFN, Pavia /Dresden, Tech. U. /Karlsruhe U., TP /Silesia U.

    2007-06-27

    We compare different procedures for combining fixed-order tree-level matrix-element generators with parton showers. We use the case of W-production at the Tevatron and the LHC to compare different implementations of the so-called CKKW and MLM schemes using different matrix-element generators and different parton cascades. We find that although similar results are obtained in all cases, there are important differences.

  6. Potential sources of analytical bias and error in selected trace element data-quality analyses

    USGS Publications Warehouse

    Paul, Angela P.; Garbarino, John R.; Olsen, Lisa D.; Rosen, Michael R.; Mebane, Christopher A.; Struzeski, Tedmund M.

    2016-09-28

    Potential sources of analytical bias and error associated with laboratory analyses for selected trace elements where concentrations were greater in filtered samples than in paired unfiltered samples were evaluated by U.S. Geological Survey (USGS) Water Quality Specialists in collaboration with the USGS National Water Quality Laboratory (NWQL) and the Branch of Quality Systems (BQS).Causes for trace-element concentrations in filtered samples to exceed those in associated unfiltered samples have been attributed to variability in analytical measurements, analytical bias, sample contamination either in the field or laboratory, and (or) sample-matrix chemistry. These issues have not only been attributed to data generated by the USGS NWQL but have been observed in data generated by other laboratories. This study continues the evaluation of potential analytical bias and error resulting from matrix chemistry and instrument variability by evaluating the performance of seven selected trace elements in paired filtered and unfiltered surface-water and groundwater samples collected from 23 sampling sites of varying chemistries from six States, matrix spike recoveries, and standard reference materials.Filtered and unfiltered samples have been routinely analyzed on separate inductively coupled plasma-mass spectrometry instruments. Unfiltered samples are treated with hydrochloric acid (HCl) during an in-bottle digestion procedure; filtered samples are not routinely treated with HCl as part of the laboratory analytical procedure. To evaluate the influence of HCl on different sample matrices, an aliquot of the filtered samples was treated with HCl. The addition of HCl did little to differentiate the analytical results between filtered samples treated with HCl from those samples left untreated; however, there was a small, but noticeable, decrease in the number of instances where a particular trace-element concentration was greater in a filtered sample than in the associated

  7. Experimental Identification of the Transmittance Matrix for any Element of the Pulsating Gas Manifold

    NASA Astrophysics Data System (ADS)

    CYKLIS, P.

    2001-07-01

    In positive-displacement compressor manifolds there are pressure pulsations due to their cyclic operation. The analysis of pressure pulsations in the compressor manifolds is important for various reasons: they directly affect the quantity of energy required for medium compression due to dynamic pressure charging, or inversely, dynamic suppression of suction and discharge processes; they cause mechanical vibrations of compressed gas piping network, they cause aerodynamic and mechanical noise; they affect the dynamics of working valves in valve compressors, they intensify the process of heat convection in heat exchangers in the gas network. The Helmholtz model used so far, which is the basis for users, who deal with pressure pulsation damping, contains many simplifying assumptions. This is because; a straight pipe segment substitutes each element of the piping system. In many cases this model is insufficient. An attempt of the analysis of other shapes was presented in references [1-3] but only simple geometry elements were considered. In other papers [4-8] the influence of the mean flow velocity caused problems. In the presented method, on the basis of pressure pulsation measurement results, firstly a division into the forward and backward going wave is determined, then the elements of the scattering (transmittance) matrix are calculated defining the installation element. This allows introducing the correction for gas mean velocity. The results of the method using correction for the gas mean velocity have been compared with the results without correction and Helmholtz model showing better accuracy.

  8. Discrete element modeling of boudinage: Insights on rock rheology, matrix flow, and evolution of geometry

    NASA Astrophysics Data System (ADS)

    Abe, Steffen; Urai, Janos L.

    2012-01-01

    We use discrete element model simulations to model the full boudinage process from initial fracturing of intact material to post-fracture flow of material into gaps between fragments and to investigate the role which the material properties of the weak and strong layers play in this process. The models are deformed in 2D plane strain under a range of confining stresses, in coaxial bulk flow. Results show that the material properties, i.e. Mohr-Coulomb or quasi-viscous for the matrix and elastic-brittle for the competent layer, lead to the development of natural looking boudin morphologies and deformation patterns in the matrix. The details of the matrix rheology only have a minor influence on the morphology of the boudins. By varying the material properties of the competent layer between fully brittle and semi-ductile we obtain a wide range of deformation patterns ranging from pinch-and-swell structures to a variety of boudin types including drawn, shear band and straight sided torn boudins. In a number of models we observe rotation of the boudin blocks despite the applied deformation being purely coaxial. These rotations are generally related to asymmetrical (rhombic) boudin shapes. Some features observed in natural boudins such as concave block faces or the formation of veins between fragments are not modeled because pore fluids are not yet included in our model.

  9. Measurement of single top quark production at D0 using a matrix element method

    SciTech Connect

    Mitrevski, Jovan Pavle

    2007-01-01

    Until now, the top quark has only been observed produced in pairs, by the strong force. According to the standard model, it can also be produced singly, via an electroweak interaction. Top quarks produced this way provide powerful ways to test the charged-current electroweak interactions of the top quark, to measure |Vtb|, and to search for physics beyond the standard model. This thesis describes the application of the matrix element analysis technique to the search for single top quark production with the D0 detector using 0.9 fb-1 of Run II data. From a comparison of the matrix element discriminants between data and the background model, assuming a Standard Model s-channel to t-channel cross section ratio of σst = 0.44, we measure the single top quark production cross section: σ(p$\\bar{p}$ → tb + X, tqb + X) = 4.8$-1.4\\atop{+1.6}$ pb. This result has a p-value of 0.08%, corresponding to a 3.2 standard deviation Gaussian equivalent significance.

  10. Many-body-localization transition: strong multifractality spectrum for matrix elements of local operators

    NASA Astrophysics Data System (ADS)

    Monthus, Cécile

    2016-07-01

    For short-ranged disordered quantum models in one dimension, the many-body-localization is analyzed via the adaptation to the many-body context (Serbyn et al 2015 Phys. Rev. X 5 041047) of the Thouless point of view on the Anderson transition: the question is whether a local interaction between two long chains is able to reshuffle completely the eigenstates (delocalized phase with a volume-law entanglement) or whether the hybridization between tensor states remains limited (many-body-localized phase with an area-law entanglement). The central object is thus the level of hybridization induced by the matrix elements of local operators, as compared with the difference of diagonal energies. The multifractal analysis of these matrix elements of local operators is used to analyze the corresponding statistics of resonances. Our main conclusion is that the critical point is characterized by the strong-multifractality spectrum f(0≤slant α ≤slant 2)=\\fracα{2} , well known in the context of Anderson localization in spaces of effective infinite dimensionality, where the size of the Hilbert space grows exponentially with the volume. Finally, the possibility of a delocalized non-ergodic phase near criticality is discussed.

  11. Measurement of single top quark production at D0 Using a matrix element method

    NASA Astrophysics Data System (ADS)

    Mitrevski, Jovan

    Until now, the top quark has only been observed produced in pairs, by the strong force. According to the standard model, it can also be produced singly, via an electroweak interaction. Top quarks produced this way provide powerful ways to test the charged-current electroweak interactions of the top quark, to measure |Vtb|, and to search for physics beyond the standard model. This thesis describes the application of the matrix element analysis technique to the search for single top quark production with the D0 detector using 0.9 fb-1 of Run II data. From a comparison of the matrix element discriminants between data and the background model, assuming a Standard Model s-channel to t-channel cross section ratio of sigmas/sigma t = 0.44, we measure the single top quark production cross section: spp¯→ tb+X,tqb+X=4.8+1.6-1.4 pb. This result has a p-value of 0.08%, corresponding to a 3.2 standard deviation Gaussian equivalent significance.

  12. Precision Measurement of the Neutron Twist-3 Matrix Element dn2: Probing Color Forces

    SciTech Connect

    Posik, Matthew; Flay, David; Parno, Diana; Allada, Kalyan; Armstrong, Whitney; Averett, Todd; Benmokhtar, Fatiha; Bertozzi, William; Camsonne, Alexandre; Canan, Mustafa; Cates, Gordon; Chen, Chunhua; Chen, Jian-Ping; Choi, Seonho; Chudakov, Eugene; Cusanno, Francesco; Dalton, Mark; Deconinck, Wouter; De Jager, Cornelis; Deng, Xiaoyan; Deur, Alexandre; Dutta, Chiranjib; El Fassi, Lamiaa; Franklin, Gregg; Friend, Megan; Gao, Haiyan; Garibaldi, Franco; Gilad, Shalev; Gilman, Ronald; Glamazdin, Oleksandr; Golge, Serkan; Gomez, Javier; Guo, Lei; Hansen, Jens-Ole; Higinbotham, Douglas; Holmstrom, Timothy; Huang, J; Hyde, Charles; Ibrahim Abdalla, Hassan; Jiang, Xiaodong; Jin, Ge; Katich, Joseph; Kelleher, Aidan; Kolarkar, Ameya; Korsch, Wolfgang; Kumbartzki, Gerfried; LeRose, John; Lindgren, Richard; Liyanage, Nilanga; Long, Elena; Lukhanin, Oleksandr; Mamyan, Vahe; McNulty, Dustin; Meziani, Zein-Eddine; Michaels, Robert; Mihovilovic, Miha; Moffit, Bryan; Muangma, Navaphon; Nanda, Sirish; Narayan, Amrendra; Nelyubin, Vladimir; Norum, Blaine; Nuruzzaman, nfn; Oh, Yongseok; Peng, Jen-chieh; Qian, Xin; Qiang, Yi; Rakhman, Abdurahim; Riordan, Seamus; Saha, Arunava; Sawatzky, Bradley; Hashemi Shabestari, Mitra; Shahinyan, Albert; Sirca, Simon; Solvignon-Slifer, Patricia; Subedi, Ramesh; Sulkosky, Vincent; Tobias, William; Troth, Wolfgang; Wang, Diancheng; Wang, Y; Wojtsekhowski, Bogdan; Yan, X; Yao, Huan; Ye, Yunxiu; Ye, Zhihong; Yuan, Lulin; Zhan, X; Zhang, Y; Zhang, Y -W; Zhao, Bo; Zheng, Xiaochao

    2014-07-01

    Double-spin asymmetries and absolute cross sections were measured at large Bjorken x (0.25 lte x lte 0.90), in both the deep-inelastic and resonance regions, by scattering longitudinally polarized electrons at beam energies of 4.7 and 5.9 GeV from a transversely and longitudinally polarized 3He target. In this dedicated experiment, the spin structure function g2 on 3He was determined with precision at large x, and the neutron twist-three matrix element dn2 was measured at ?Q2? of 3.21 and 4.32 GeV2/c2, with an absolute precision of about 10?5. Our results are found to be in agreement with lattice QCD calculations and resolve the disagreement found with previous data at ?Q2?= 5 GeV2/c2. Combining dn2 and a newly extracted twist-four matrix element, fn2, the average neutron color electric and magnetic forces were extracted and found to be of opposite sign and about 60 MeV/fm in magnitude.

  13. Top Quark Mass Measurement in the Lepton plus Jets Channel Using a Modified Matrix Element Method

    SciTech Connect

    Aaltonen, T.; Adelman, J.; Akimoto, T.; Alvarez Gonzalez, B.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A.; Antos, J.; Apollinari, G.; Apresyan, A.; /Purdue U. /Waseda U.

    2008-12-01

    The authors report a measurement of the top quark mass, m{sub t}, obtained from p{bar p} collisions at {radical}s = 1.96 TeV at the Fermilab Tevatron using the CDF II detector. They analyze a sample corresponding to an integrated luminosity of 1.9 rfb{sup -1}. They select events with an electron or muon, large missing transverse energy, and exactly four high-energy jets in the central region of the detector, at least one of which is tagged as coming from a b quark. They calculate a signal likelihood using a matrix element integration method, where the matrix element is modified by using effective propagators to take into account assumptions on event kinematics. The event likelihood is a function of m{sub t} and a parameter JES that determines in situ the calibration of the jet energies. They use a neural network discriminant to distinguish signal from background events. They also apply a cut on the peak value of each event likelihood curve to reduce the contribution of background and badly reconstructed events. Using the 318 events that pass all selection criteria, they find m{sub t} = 172.7 {+-} 1.8 (stat. + JES) {+-} 1.2(syst.) GeV/c{sup 2}.

  14. SU(3) flavor breaking in hadronic matrix elements for B-B¯ oscillations

    NASA Astrophysics Data System (ADS)

    Bernard, C.; Blum, T.; Soni, A.

    1998-07-01

    Results in the quenched approximation for SU(3) breaking ratios of the heavy-light decay constants and the ΔF=2 mixing matrix elements are reported. Using lattice simulations at 6/g2=5.7, 5.85, 6.0, and 6.3, we directly compute the mixing matrix element Mhl=. Extrapolating to the physical B meson states, B0 and B0s, we obtain Mbs/Mbd=1.76(10)+57-42 in the continuum limit. The systematic error includes the errors within the quenched approximation but not the errors of quenching. We also obtain the ratio of decay constants, fbs/fbd=1.17(2)+12-6. For the B parameters we find Bbs(2 GeV)=Bbd(2 GeV)=1.02(13); we cannot resolve the SU(3) breaking effects in this case.

  15. Overcoming Matrix Effects in a Complex Sample: Analysis of Multiple Elements in Multivitamins by Atomic Absorption Spectroscopy

    ERIC Educational Resources Information Center

    Arnold, Randy J.; Arndt, Brett; Blaser, Emilia; Blosser, Chris; Caulton, Dana; Chung, Won Sog; Fiorenza, Garrett; Heath, Wyatt; Jacobs, Alex; Kahng, Eunice; Koh, Eun; Le, Thao; Mandla, Kyle; McCory, Chelsey; Newman, Laura; Pithadia, Amit; Reckelhoff, Anna; Rheinhardt, Joseph; Skljarevski, Sonja; Stuart, Jordyn; Taylor, Cassie; Thomas, Scott; Tse, Kyle; Wall, Rachel; Warkentien, Chad

    2011-01-01

    A multivitamin tablet and liquid are analyzed for the elements calcium, magnesium, iron, zinc, copper, and manganese using atomic absorption spectrometry. Linear calibration and standard addition are used for all elements except calcium, allowing for an estimate of the matrix effects encountered for this complex sample. Sample preparation using…

  16. Hyperon-nucleus folding potentials in the complex G-matrix approach

    NASA Astrophysics Data System (ADS)

    Furumoto, T.; Sakuragi, Y.; Yamamoto, Y.

    2010-04-01

    We have constructed the hyperon-nucleus optical potential based on the complex G-matrix folding model. The complex G-matrix interactions are derived from the extended-soft core (ESC) model interactions, ESC04a and ESC08. The elastic cross sections and analyzing powers are calculated using the folding-model potentials (FMPs) based on the complex G-matrix interactions. The strength functions for the ( π, K) reaction are also obtained using the FMPs and are compared with the result calculated with a phenomenological repulsive optical potential. The ESC08 interaction gives a better result than does ESC04a.

  17. Single element of the matrix source of negative hydrogen ions: Measurements of the extracted currents combined with diagnostics.

    PubMed

    Yordanov, D; Lishev, St; Shivarova, A

    2016-02-01

    Combining measurements of the extracted currents with probe and laser-photodetachment diagnostics, the study is an extension of recent tests of factors and gas-discharge conditions stimulating the extraction of volume produced negative ions. The experiment is in a single element of a rf source with the design of a matrix of small-radius inductively driven discharges. The results are for the electron and negative-ion densities, for the plasma potential and for the electronegativity in the vicinity of the plasma electrode as well as for the currents of the extracted negative ions and electrons. The plasma-electrode bias and the rf power have been varied. Necessity of a high bias to the plasma electrode and stable linear increase of the extracted currents with the rf power are the main conclusions.

  18. Analytical expressions for the transfer matrix to standardize scalp potentials to infinity reference.

    PubMed

    Thuraisingham, Ranjit Arulnayagam

    2011-11-01

    A procedure based on the multiple expansion of the brain electrical generator is used here to derive analytical expressions for the transfer matrix necessary to obtain potentials referenced to infinity. Its features include: avoidance of computations that involve a large number of discrete dipole sources; faster evaluation compared to the use of the dipole layer; and a transparency showing the parameters that constitute the transfer matrix. The paper also proposes the construction of the standardization matrix without the use of the general inverse of a non-symmetrical matrix.

  19. Measurement of the first ionization potential of lawrencium, element 103.

    PubMed

    Sato, T K; Asai, M; Borschevsky, A; Stora, T; Sato, N; Kaneya, Y; Tsukada, K; Düllmann, Ch E; Eberhardt, K; Eliav, E; Ichikawa, S; Kaldor, U; Kratz, J V; Miyashita, S; Nagame, Y; Ooe, K; Osa, A; Renisch, D; Runke, J; Schädel, M; Thörle-Pospiech, P; Toyoshima, A; Trautmann, N

    2015-04-01

    The chemical properties of an element are primarily governed by the configuration of electrons in the valence shell. Relativistic effects influence the electronic structure of heavy elements in the sixth row of the periodic table, and these effects increase dramatically in the seventh row--including the actinides--even affecting ground-state configurations. Atomic s and p1/2 orbitals are stabilized by relativistic effects, whereas p3/2, d and f orbitals are destabilized, so that ground-state configurations of heavy elements may differ from those of lighter elements in the same group. The first ionization potential (IP1) is a measure of the energy required to remove one valence electron from a neutral atom, and is an atomic property that reflects the outermost electronic configuration. Precise and accurate experimental determination of IP1 gives information on the binding energy of valence electrons, and also, therefore, on the degree of relativistic stabilization. However, such measurements are hampered by the difficulty in obtaining the heaviest elements on scales of more than one atom at a time. Here we report that the experimentally obtained IP1 of the heaviest actinide, lawrencium (Lr, atomic number 103), is 4.96(+0.08)(-0.07) electronvolts. The IP1 of Lr was measured with (256)Lr (half-life 27 seconds) using an efficient surface ion-source and a radioisotope detection system coupled to a mass separator. The measured IP1 is in excellent agreement with the value of 4.963(15) electronvolts predicted here by state-of-the-art relativistic calculations. The present work provides a reliable benchmark for theoretical calculations and also opens the way for IP1 measurements of superheavy elements (that is, transactinides) on an atom-at-a-time scale.

  20. Measurement of the first ionization potential of lawrencium, element 103

    NASA Astrophysics Data System (ADS)

    Sato, T. K.; Asai, M.; Borschevsky, A.; Stora, T.; Sato, N.; Kaneya, Y.; Tsukada, K.; Düllmann, Ch. E.; Eberhardt, K.; Eliav, E.; Ichikawa, S.; Kaldor, U.; Kratz, J. V.; Miyashita, S.; Nagame, Y.; Ooe, K.; Osa, A.; Renisch, D.; Runke, J.; Schädel, M.; Thörle-Pospiech, P.; Toyoshima, A.; Trautmann, N.

    2015-04-01

    The chemical properties of an element are primarily governed by the configuration of electrons in the valence shell. Relativistic effects influence the electronic structure of heavy elements in the sixth row of the periodic table, and these effects increase dramatically in the seventh row--including the actinides--even affecting ground-state configurations. Atomic s and p1/2 orbitals are stabilized by relativistic effects, whereas p3/2, d and f orbitals are destabilized, so that ground-state configurations of heavy elements may differ from those of lighter elements in the same group. The first ionization potential (IP1) is a measure of the energy required to remove one valence electron from a neutral atom, and is an atomic property that reflects the outermost electronic configuration. Precise and accurate experimental determination of IP1 gives information on the binding energy of valence electrons, and also, therefore, on the degree of relativistic stabilization. However, such measurements are hampered by the difficulty in obtaining the heaviest elements on scales of more than one atom at a time. Here we report that the experimentally obtained IP1 of the heaviest actinide, lawrencium (Lr, atomic number 103), is electronvolts. The IP1 of Lr was measured with 256Lr (half-life 27 seconds) using an efficient surface ion-source and a radioisotope detection system coupled to a mass separator. The measured IP1 is in excellent agreement with the value of 4.963(15) electronvolts predicted here by state-of-the-art relativistic calculations. The present work provides a reliable benchmark for theoretical calculations and also opens the way for IP1 measurements of superheavy elements (that is, transactinides) on an atom-at-a-time scale.

  1. Measurement of the first ionization potential of lawrencium, element 103.

    PubMed

    Sato, T K; Asai, M; Borschevsky, A; Stora, T; Sato, N; Kaneya, Y; Tsukada, K; Düllmann, Ch E; Eberhardt, K; Eliav, E; Ichikawa, S; Kaldor, U; Kratz, J V; Miyashita, S; Nagame, Y; Ooe, K; Osa, A; Renisch, D; Runke, J; Schädel, M; Thörle-Pospiech, P; Toyoshima, A; Trautmann, N

    2015-04-01

    The chemical properties of an element are primarily governed by the configuration of electrons in the valence shell. Relativistic effects influence the electronic structure of heavy elements in the sixth row of the periodic table, and these effects increase dramatically in the seventh row--including the actinides--even affecting ground-state configurations. Atomic s and p1/2 orbitals are stabilized by relativistic effects, whereas p3/2, d and f orbitals are destabilized, so that ground-state configurations of heavy elements may differ from those of lighter elements in the same group. The first ionization potential (IP1) is a measure of the energy required to remove one valence electron from a neutral atom, and is an atomic property that reflects the outermost electronic configuration. Precise and accurate experimental determination of IP1 gives information on the binding energy of valence electrons, and also, therefore, on the degree of relativistic stabilization. However, such measurements are hampered by the difficulty in obtaining the heaviest elements on scales of more than one atom at a time. Here we report that the experimentally obtained IP1 of the heaviest actinide, lawrencium (Lr, atomic number 103), is 4.96(+0.08)(-0.07) electronvolts. The IP1 of Lr was measured with (256)Lr (half-life 27 seconds) using an efficient surface ion-source and a radioisotope detection system coupled to a mass separator. The measured IP1 is in excellent agreement with the value of 4.963(15) electronvolts predicted here by state-of-the-art relativistic calculations. The present work provides a reliable benchmark for theoretical calculations and also opens the way for IP1 measurements of superheavy elements (that is, transactinides) on an atom-at-a-time scale. PMID:25855457

  2. Measurement of the top quark mass using the matrix element technique in dilepton final states

    DOE PAGES

    Abazov, V. M.; Abbott, B.; Acharya, B. S.; Adams, M.; Adams, T.; Agnew, J. P.; Alexeev, G. D.; Alkhazov, G.; Alton, A.; Askew, A.; et al

    2016-08-18

    Here, we present a measurement of the top quark mass in pp collisions at a center-of-mass energy of 1.96 TeV at the Fermilab Tevatron collider. The data were collected by the D0 experiment corresponding to an integrated luminosity of 9.7 fb-1. The matrix element technique is applied to tt events in the final state containing leptons (electrons or muons) with high transverse momenta and at least two jets. The calibration of the jet energy scale determined in the lepton+jets final state of tt decays is applied to jet energies. This correction provides a substantial reduction in systematic uncertainties. We obtain amore » top quark mass of mt = 173.93±1.84 GeV.« less

  3. Measurement of the top quark mass using the matrix element technique in dilepton final states

    NASA Astrophysics Data System (ADS)

    Abazov, V. M.; Abbott, B.; Acharya, B. S.; Adams, M.; Adams, T.; Agnew, J. P.; Alexeev, G. D.; Alkhazov, G.; Alton, A.; Askew, A.; Atkins, S.; Augsten, K.; Aushev, V.; Aushev, Y.; Avila, C.; Badaud, F.; Bagby, L.; Baldin, B.; Bandurin, D. V.; Banerjee, S.; Barberis, E.; Baringer, P.; Bartlett, J. F.; Bassler, U.; Bazterra, V.; Bean, A.; Begalli, M.; Bellantoni, L.; Beri, S. B.; Bernardi, G.; Bernhard, R.; Bertram, I.; Besançon, M.; Beuselinck, R.; Bhat, P. C.; Bhatia, S.; Bhatnagar, V.; Blazey, G.; Blessing, S.; Bloom, K.; Boehnlein, A.; Boline, D.; Boos, E. E.; Borissov, G.; Borysova, M.; Brandt, A.; Brandt, O.; Brochmann, M.; Brock, R.; Bross, A.; Brown, D.; Bu, X. B.; Buehler, M.; Buescher, V.; Bunichev, V.; Burdin, S.; Buszello, C. P.; Camacho-Pérez, E.; Casey, B. C. K.; Castilla-Valdez, H.; Caughron, S.; Chakrabarti, S.; Chan, K. M.; Chandra, A.; Chapon, E.; Chen, G.; Cho, S. W.; Choi, S.; Choudhary, B.; Cihangir, S.; Claes, D.; Clutter, J.; Cooke, M.; Cooper, W. E.; Corcoran, M.; Couderc, F.; Cousinou, M.-C.; Cuth, J.; Cutts, D.; Das, A.; Davies, G.; de Jong, S. J.; De La Cruz-Burelo, E.; Déliot, F.; Demina, R.; Denisov, D.; Denisov, S. P.; Desai, S.; Deterre, C.; DeVaughan, K.; Diehl, H. T.; Diesburg, M.; Ding, P. F.; Dominguez, A.; Dubey, A.; Dudko, L. V.; Duperrin, A.; Dutt, S.; Eads, M.; Edmunds, D.; Ellison, J.; Elvira, V. D.; Enari, Y.; Evans, H.; Evdokimov, A.; Evdokimov, V. N.; Fauré, A.; Feng, L.; Ferbel, T.; Fiedler, F.; Filthaut, F.; Fisher, W.; Fisk, H. E.; Fortner, M.; Fox, H.; Franc, J.; Fuess, S.; Garbincius, P. H.; Garcia-Bellido, A.; García-González, J. A.; Gavrilov, V.; Geng, W.; Gerber, C. E.; Gershtein, Y.; Ginther, G.; Gogota, O.; Golovanov, G.; Grannis, P. D.; Greder, S.; Greenlee, H.; Grenier, G.; Gris, Ph.; Grivaz, J.-F.; Grohsjean, A.; Grünendahl, S.; Grünewald, M. W.; Guillemin, T.; Gutierrez, G.; Gutierrez, P.; Haley, J.; Han, L.; Harder, K.; Harel, A.; Hauptman, J. M.; Hays, J.; Head, T.; Hebbeker, T.; Hedin, D.; Hegab, H.; Heinson, A. P.; Heintz, U.; Hensel, C.; Heredia-De La Cruz, I.; Herner, K.; Hesketh, G.; Hildreth, M. D.; Hirosky, R.; Hoang, T.; Hobbs, J. D.; Hoeneisen, B.; Hogan, J.; Hohlfeld, M.; Holzbauer, J. L.; Howley, I.; Hubacek, Z.; Hynek, V.; Iashvili, I.; Ilchenko, Y.; Illingworth, R.; Ito, A. S.; Jabeen, S.; Jaffré, M.; Jayasinghe, A.; Jeong, M. S.; Jesik, R.; Jiang, P.; Johns, K.; Johnson, E.; Johnson, M.; Jonckheere, A.; Jonsson, P.; Joshi, J.; Jung, A. W.; Juste, A.; Kajfasz, E.; Karmanov, D.; Katsanos, I.; Kaur, M.; Kehoe, R.; Kermiche, S.; Khalatyan, N.; Khanov, A.; Kharchilava, A.; Kharzheev, Y. N.; Kiselevich, I.; Kohli, J. M.; Kozelov, A. V.; Kraus, J.; Kumar, A.; Kupco, A.; Kurča, T.; Kuzmin, V. A.; Lammers, S.; Lebrun, P.; Lee, H. S.; Lee, S. W.; Lee, W. M.; Lei, X.; Lellouch, J.; Li, D.; Li, H.; Li, L.; Li, Q. Z.; Lim, J. K.; Lincoln, D.; Linnemann, J.; Lipaev, V. V.; Lipton, R.; Liu, H.; Liu, Y.; Lobodenko, A.; Lokajicek, M.; Lopes de Sa, R.; Luna-Garcia, R.; Lyon, A. L.; Maciel, A. K. A.; Madar, R.; Magaña-Villalba, R.; Malik, S.; Malyshev, V. L.; Mansour, J.; Martínez-Ortega, J.; McCarthy, R.; McGivern, C. L.; Meijer, M. M.; Melnitchouk, A.; Menezes, D.; Mercadante, P. G.; Merkin, M.; Meyer, A.; Meyer, J.; Miconi, F.; Mondal, N. K.; Mulhearn, M.; Nagy, E.; Narain, M.; Nayyar, R.; Neal, H. A.; Negret, J. P.; Neustroev, P.; Nguyen, H. T.; Nunnemann, T.; Orduna, J.; Osman, N.; Pal, A.; Parashar, N.; Parihar, V.; Park, S. K.; Partridge, R.; Parua, N.; Patwa, A.; Penning, B.; Perfilov, M.; Peters, Y.; Petridis, K.; Petrillo, G.; Pétroff, P.; Pleier, M.-A.; Podstavkov, V. M.; Popov, A. V.; Prewitt, M.; Price, D.; Prokopenko, N.; Qian, J.; Quadt, A.; Quinn, B.; Ratoff, P. N.; Razumov, I.; Ripp-Baudot, I.; Rizatdinova, F.; Rominsky, M.; Ross, A.; Royon, C.; Rubinov, P.; Ruchti, R.; Sajot, G.; Sánchez-Hernández, A.; Sanders, M. P.; Santos, A. S.; Savage, G.; Savitskyi, M.; Sawyer, L.; Scanlon, T.; Schamberger, R. D.; Scheglov, Y.; Schellman, H.; Schott, M.; Schwanenberger, C.; Schwienhorst, R.; Sekaric, J.; Severini, H.; Shabalina, E.; Shary, V.; Shaw, S.; Shchukin, A. A.; Simak, V.; Skubic, P.; Slattery, P.; Snow, G. R.; Snow, J.; Snyder, S.; Söldner-Rembold, S.; Sonnenschein, L.; Soustruznik, K.; Stark, J.; Stefaniuk, N.; Stoyanova, D. A.; Strauss, M.; Suter, L.; Svoisky, P.; Titov, M.; Tokmenin, V. V.; Tsai, Y.-T.; Tsybychev, D.; Tuchming, B.; Tully, C.; Uvarov, L.; Uvarov, S.; Uzunyan, S.; Van Kooten, R.; van Leeuwen, W. M.; Varelas, N.; Varnes, E. W.; Vasilyev, I. A.; Verkheev, A. Y.; Vertogradov, L. S.; Verzocchi, M.; Vesterinen, M.; Vilanova, D.; Vokac, P.; Wahl, H. D.; Wang, M. H. L. S.; Warchol, J.; Watts, G.; Wayne, M.; Weichert, J.; Welty-Rieger, L.; Williams, M. R. J.; Wilson, G. W.; Wobisch, M.; Wood, D. R.; Wyatt, T. R.; Xie, Y.; Yamada, R.; Yang, S.; Yasuda, T.; Yatsunenko, Y. A.; Ye, W.; Ye, Z.; Yin, H.; Yip, K.; Youn, S. W.; Yu, J. M.; Zennamo, J.; Zhao, T. G.; Zhou, B.; Zhu, J.; Zielinski, M.; Zieminska, D.; Zivkovic, L.; D0 Collaboration

    2016-08-01

    We present a measurement of the top quark mass in p p ¯ collisions at a center-of-mass energy of 1.96 TeV at the Fermilab Tevatron collider. The data were collected by the D0 experiment corresponding to an integrated luminosity of 9.7 fb-1 . The matrix element technique is applied to t t ¯ events in the final state containing leptons (electrons or muons) with high transverse momenta and at least two jets. The calibration of the jet energy scale determined in the lepton +jets final state of t t ¯ decays is applied to jet energies. This correction provides a substantial reduction in systematic uncertainties. We obtain a top quark mass of mt=173.93 ±1.84 GeV .

  4. Influence of Pairing on the Nuclear Matrix Elements of the Neutrinoless {beta}{beta} Decays

    SciTech Connect

    Caurier, E.; Nowacki, F.

    2008-02-08

    We study in this Letter the neutrinoless double beta decay nuclear matrix elements (NME's) in the framework of the interacting shell model. We analyze them in terms of the total angular momentum of the decaying neutron pair and as a function of the seniority truncations in the nuclear wave functions. This point of view turns out to be very adequate to gauge the accuracy of the NME's predicted by different nuclear models. In addition, it gives back the protagonist role in this process to the pairing interaction, the one which is responsible for the very existence of double beta decay emitters. We show that low seniority approximations, comparable to those implicit in the quasiparticle RPA in a spherical basis, tend to overestimate the NME's in several decays.

  5. Spin dipole nuclear matrix elements for double beta decay nuclei by charge-exchange reactions

    NASA Astrophysics Data System (ADS)

    Ejiri, H.; Frekers, D.

    2016-11-01

    Spin dipole (SD) strengths for double beta-decay (DBD) nuclei were studied experimentally for the first time by using measured cross sections of (3He, t) charge-exchange reactions (CERs). Then SD nuclear matrix elements (NMEs) {M}α ({{SD}}) for low-lying 2‑ states were derived from the experimental SD strengths by referring to the experimental α = GT (Gamow–Teller) and α = F (Fermi) strengths. They are consistent with the empirical NMEs M({{SD}}) based on the quasi-particle model with the empirical effective SD coupling constant. The CERs are used to evaluate the SD NME, which is associated with one of the major components of the neutrino-less DBD NME.

  6. Differential cross sections and spin density matrix elements for the reaction γp→pω

    NASA Astrophysics Data System (ADS)

    Williams, M.; Applegate, D.; Bellis, M.; Meyer, C. A.; Adhikari, K. P.; Anghinolfi, M.; Baghdasaryan, H.; Ball, J.; Battaglieri, M.; Bedlinskiy, I.; Berman, B. L.; Biselli, A. S.; Bookwalter, C.; Briscoe, W. J.; Brooks, W. K.; Burkert, V. D.; Careccia, S. L.; Carman, D. S.; Cole, P. L.; Collins, P.; Crede, V.; D'Angelo, A.; Daniel, A.; Vita, R. De; Sanctis, E. De; Deur, A.; Dey, B.; Dhamija, S.; Dickson, R.; Djalali, C.; Dodge, G. E.; Doughty, D.; Dugger, M.; Dupre, R.; Alaoui, A. El; Elouadrhiri, L.; Eugenio, P.; Fedotov, G.; Fegan, S.; Fradi, A.; Gabrielyan, M. Y.; Garçon, M.; Gevorgyan, N.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Gohn, W.; Golovatch, E.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Guo, L.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Hassall, N.; Hicks, K.; Holtrop, M.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jawalkar, S. S.; Jo, H. S.; Johnstone, J. R.; Joo, K.; Keller, D.; Khandaker, M.; Khetarpal, P.; Kim, W.; Klein, A.; Klein, F. J.; Krahn, Z.; Kubarovsky, V.; Kuleshov, S. V.; Kuznetsov, V.; Livingston, K.; Lu, H. Y.; Mayer, M.; McAndrew, J.; McCracken, M. E.; McKinnon, B.; Mikhailov, K.; Mirazita, M.; Mokeev, V.; Moreno, B.; Moriya, K.; Morrison, B.; Moutarde, H.; Munevar, E.; Nadel-Turonski, P.; Nepali, C. S.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Niroula, M. R.; Niyazov, R. A.; Osipenko, M.; Ostrovidov, A. I.; Paris, M.; Park, K.; Park, S.; Pasyuk, E.; Pereira, S. Anefalos; Perrin, Y.; Pisano, S.; Pogorelko, O.; Pozdniakov, S.; Price, J. W.; Procureur, S.; Protopopescu, D.; Raue, B. A.; Ricco, G.; Ripani, M.; Ritchie, B. G.; Rosner, G.; Rossi, P.; Sabatié, F.; Saini, M. S.; Salamanca, J.; Salgado, C.; Schott, D.; Schumacher, R. A.; Seraydaryan, H.; Sharabian, Y. G.; Smith, E. S.; Sober, D. I.; Sokhan, D.; Stepanyan, S. S.; Stoler, P.; Strakovsky, I. I.; Strauch, S.; Taiuti, M.; Tedeschi, D. J.; Tkachenko, S.; Ungaro, M.; Vineyard, M. F.; Voutier, E.; Watts, D. P.; Weinstein, L. B.; Weygand, D. P.; Wood, M. H.; Zhang, J.; Zhao, B.

    2009-12-01

    High-statistics differential cross sections and spin-density matrix elements for the reaction γp→pω have been measured using the CEBAF large acceptance spectrometer (CLAS) at Jefferson Lab for center-of-mass (c.m.) energies from threshold up to 2.84 GeV. Results are reported in 11210-MeV wide c.m. energy bins, each subdivided into cosθc.m.ω bins of width 0.1. These are the most precise and extensive ω photoproduction measurements to date. A number of prominent structures are clearly present in the data. Many of these have not previously been observed due to limited statistics in earlier measurements.

  7. OMC studies for the matrix elements in ββ decay

    SciTech Connect

    Zinatulina, D.; Brudanin, V.; Egorov, V.; Shirchenko, M.; Vasiliev, R.; Yyutlandov, I.; Briançon, Ch.; Petitjean, C.

    2013-12-30

    Energy and time spectra of gamma-rays following μ-capture in natural Kr, Se, Cd and Sm, as well as isotopic enriched {sup 82}Kr, {sup 76}Se, {sup 106}Cd and {sup 150}Sm, have been measured. Total life-times of muons in different isotopes, as well as partial μ-capture rates to the excited states of {sup 48}Sc, {sup 76}As and {sup 106}Ag, were extracted. These results are discussed in the context of the double-beta decay matrix elements. The data are also compared with data from theoretical calculations and with data from charge-exchange reactions on {sup 48}Ti. It is the first time that μ-capture and charge-exchange reaction data are being compared in the context of ββ decay.

  8. Three-dimensional display utilizing a diffractive optical element and an active matrix liquid crystal display

    NASA Astrophysics Data System (ADS)

    Nordin, Gregory P.; Jones, Michael W.; Kulick, Jeffrey H.; Lindquist, Robert G.; Kowel, Stephen T.

    1996-12-01

    We describe the design, construction, and performance of the first real-time autostereoscopic 3D display based on the partial pixel 3D display architecture. The primary optical components of the 3D display are an active-matrix liquid crystal display and a diffractive optical element (DOE). The display operates at video frame rates and is driven with a conventional VGA signal. 3D animations with horizontal motion parallax are readily viewable as sets of stereo images. Formation of the virtual viewing slits by diffraction from the partial pixel apertures is experimentally verified. The measured contrast and perceived brightness of the display are excellent, but there are minor flaws in image quality due to secondary images. The source of these images and how they may be eliminated is discussed. The effects of manufacturing-related systematic errors in the DOE are also analyzed.

  9. HELAC-Onia: An automatic matrix element generator for heavy quarkonium physics

    NASA Astrophysics Data System (ADS)

    Shao, Hua-Sheng

    2013-11-01

    By the virtues of the Dyson-Schwinger equations, we upgrade the published code HELAC to be capable to calculate the heavy quarkonium helicity amplitudes in the framework of NRQCD factorization, which we dub HELAC-Onia. We rewrote the original HELAC to make the new program be able to calculate helicity amplitudes of multi P-wave quarkonium states production at hadron colliders and electron-positron colliders by including new P-wave off-shell currents. Therefore, besides the high efficiencies in computation of multi-leg processes within the Standard Model, HELAC-Onia is also sufficiently numerical stable in dealing with P-wave quarkonia (e.g. h,χ) and P-wave color-octet intermediate states. To the best of our knowledge, it is a first general-purpose automatic quarkonium matrix elements generator based on recursion relations on the market.

  10. An iterative parallel sparse matrix equation solver with application to finite element modeling of electromagnetic scattering

    SciTech Connect

    Cwik, T.; Jamnejad, V.; Zuffada, C.

    1994-12-31

    The usefulness of finite element modeling follows from the ability to accurately simulate the geometry and three-dimensional fields on the scale of a fraction of a wavelength. To make this modeling practical for engineering design, it is necessary to integrate the stages of geometry modeling and mesh generation, numerical solution of the fields-a stage heavily dependent on the efficient use of a sparse matrix equation solver, and display of field information. The stages of geometry modeling, mesh generation, and field display are commonly completed using commercially available software packages. Algorithms for the numerical solution of the fields need to be written for the specific class of problems considered. Interior problems, i.e. simulating fields in waveguides and cavities, have been successfully solved using finite element methods. Exterior problems, i.e. simulating fields scattered or radiated from structures, are more difficult to model because of the need to numerically truncate the finite element mesh. To practically compute a solution to exterior problems, the domain must be truncated at some finite surface where the Sommerfeld radiation condition is enforced, either approximately or exactly. Approximate methods attempt to truncate the mesh using only local field information at each grid point, whereas exact methods are global, needing information from the entire mesh boundary. In this work, a method that couples three-dimensional finite element (FE) solutions interior to the bounding surface, with an efficient integral equation (IE) solution that exactly enforces the Sommerfeld radiation condition is developed. The bounding surface is taken to be a surface of revolution (SOR) to greatly reduce computational expense in the IE portion of the modeling.

  11. Matrix elements of four-fermion operators with quenched Wilson fermions

    NASA Astrophysics Data System (ADS)

    Gupta, Rajan; Bhattacharya, Tanmoy; Sharpe, Stephen R.

    1997-04-01

    We present results for the matrix elements of a variety of four-fermion operators calculated using quenched Wilson fermions. Our simulations are done on 170 lattices of size 323×64 at β=6.0. We find BK=0.74+/-0.04+/-0.05, BD=0.78+/-0.01, B3/27=0.58+/-0.02+0.07-0.03, B3/28=0.81+/-0.03+0.03-0.02, with all results being in the NDR scheme at μ=2 GeV. We also calculate the B parameter for the operator Qs, which is needed in the study of the difference of B-meson lifetimes. Our best estimate is BS(NDR,μ=1/a=2.33 GeV) =0.80+/-0.01. This is given at the lattice scale since the required two-loop anomalous dimension matrix is not known. In all these estimates, the first error is statistical, while the second is due to the use of truncated perturbation theory to match continuum and lattice operators. Errors due to quenching and lattice discretization are not included. We also present new results for the perturbative matching coefficients, extending the calculation to all Lorentz scalar four-fermion operators, and using NDR as the continuum scheme.

  12. Nuclear-Structure Data Relevant to Neutinoless-Double-Beta-Decay Matrix Elements

    NASA Astrophysics Data System (ADS)

    Kay, Benjamin

    2015-10-01

    An observation of neutrinoless double beta decay is one of the most exciting prospects in contemporary physics. It follows that calculations of the nuclear matrix elements for this process are of high priority. The change in the wave functions between the initial and final states of the neutrinoless-double-beta-decay candidates 76Ge-->76Se, 100Mo-->100Ru, 130Te-->130Xe, and 136Xe-->136Ba have been studied with transfer reactions. The data are focused on the change in the occupancies of the valence orbitals in the ground states as two neutrons decay into two protons. The results set a strict constraint on any theoretical calculations describing this rearrangement and thus on the magnitude of the nuclear matrix elements for this process, which currently exhibit uncertainties at the factor of 2-4 level. Prior to these measurements there were limited experimental data were available A = 76 and 100 systems, and very limited data for the A = 130 and 136 systems, in a large part due to the gaseous Xe isotopes involved. The uncertainties on most of these data are estimated to range from 0.1-0.3 nucleons. The program started with the A = 76 system, with subsequent calculations, modified to reproduce the experimental occupancies, exhibiting a significant reduction in the discrepancy between various models. New data are available for the A = 100 , 130, and 136 systems. I review the program, making detailed comparisons between the latest theoretical calculations and the experimental data where available. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, under Contract Number DE-AC02-06CH11357.

  13. FRODO: a MuPAD program to calculate matrix elements between contracted wavefunctions

    NASA Astrophysics Data System (ADS)

    Angeli, C.; Cimiraglia, R.

    2005-09-01

    A symbolic program performing the Formal Reduction of Density Operators (FRODO) has been developed in the MuPAD computer algebra system with the purpose of evaluating the matrix elements of the electronic Hamiltonian between internally contracted functions in a complete active space (CAS) scheme. The program is illustrated making use of two meaningful examples. Program summaryTitle of program:FRODO Catalogue identifier:ADVY Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADVY Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland Computer:Any computer on which the MuPAD computer algebra system can be installed Operating systems under which the program has been tested:Linux Programming language used:MuPAD vs. 2.5.3 for Linux No. of lines in distributed program, including test data, etc.:3939 No. of bytes in distributed program, including test data, etc.:19 661 Distribution format:tar.gz Nature of physical problem: In order to improve on the CAS-SCF wavefunction one can resort to multireference perturbation theory or configuration interaction based on internally contracted functions (ICF) which are obtained by application of the excitation operators to the reference CAS-SCF wavefunction. The formulation of such matrix elements is quite cumbersome and a computer algebra system like MuPAD appears ideally suited to perform such a task. Method of solution: The method adopted consists in successively eliminating all occurrences of inactive orbital indices (core and virtual) from the products of excitation operators which appear in the definition of the ICF's and in the electronic Hamiltonian expressed in the second quantization formalism. Restrictions due to the complexity of the problem: The program is limited to no more than doubly excited ICF's.

  14. s-wave repulsion in the pion-nucleus optical potential and the subthreshold pion-nucleon T matrix

    NASA Astrophysics Data System (ADS)

    Bhalerao, R. S.; Shakin, C. M.

    1981-05-01

    A covariant theory of the pion-nucleus interaction has been used to calculate off-shell matrix elements of the first-order pion-nucleus optical potential in momentum space. The matrix elements are calculated for 16O and 40Ca, as a function of k, the momentum in the π-nucleus center-of-mass system, for W=mπ+MN. (As in our previous studies we have carried out a full integration over the Fermi motion of the target nucleons. Off-shell effects related to nuclear binding are treated carefully.) As this calculation is sensitively dependent upon the subthreshold πN T matrix, two different models for the T matrix are studied. One is the well known separable model of Londergan, McVoy, and Moniz. The second model includes terms describing the direct and crossed Born terms and therefore has the appropriate s- and u-channel nucleon poles. (In the calculations using this model both the pion and the nucleon are allowed to go off the mass shell.) The remaining part of the amplitude in the second model is represented by a separable form. For small k, the matrix elements of the optical potential calculated with these two models are significantly larger than those obtained when use is made of the fixed-scatterer approximation. Phenomenological optical potentials which describe low-energy pion-nucleus scattering data or pionic-atom data exhibit s-wave repulsion which is about 2-8 times that obtained from calculations made in the fixed-scatterer approximation. (The uncertainty in this enhancement factor reflects the uncertainty in the free-space values of the πN scattering lengths). We conclude that the explanation of a significant fraction of the s-wave repulsion in the low energy pion-nucleus interaction may lie in a careful treatment of off-shell effects using a good model for the subthreshold πN T matrix. NUCLEAR REACTIONS Pion-nucleus interactions, off-shell effects in the pion-nucleus interaction at low energy; pionic atoms.

  15. Modes of occurrence of potentially hazardous elements in coal: levels of confidence

    USGS Publications Warehouse

    Finkelman, R.B.

    1994-01-01

    The modes of occurrence of the potentially hazardous elements in coal will be of significance in any attempt to reduce their mobilization due to coal combustion. Antimony and selenium may be present in solid solution in pyrite, as minute accessory sulfides dispersed throughout the organic matrix, or in organic association. Because of these modes of occurrence it is anticipated that less than 50% of these elements will be routinely removed by conventional coal cleaning procedures. Arsenic and mercury occur primarily in late-stage coarse-grained pyrite therefore physical coal cleaning procedures should be successful in removing substantial proportions of these elements. Cadmium occurs in sphalerite and lead in galena. Both of these minerals exhibit a wide range of particle sizes and textural relations. Depending on the particle size and textural relations, physical coal cleaning may remove as little as 25% of these elements or as much as 75%. Manganese in bituminous coal occurs in carbonates, especially siderite. Physical coal cleaning should remove a substantial proportion of this element. More information is needed to elucidate the modes of occurrence of beryllium, chromium, cobalt, and nickel. ?? 1994.

  16. Spin Density Matrix Elements in Exclusive Production of Omega Mesons at HERMES

    NASA Astrophysics Data System (ADS)

    Marukyan, Hrachya

    2016-02-01

    Exclusive electroproduction of ω mesons on unpolarized hydrogen and deuterium targets is studied at HERMES in the kinematic region of Q2 > 1.0GeV2, 3.0GeV < W < 6.3GeV, and ‑ t‧ < 0.2GeV2. The data were accumulated during the 1996-2007 running period using the 27.6GeV longitudinally polarized electron or positron beams at HERA. The determination of the virtual-photon longitudinal-to-transverse cross-section ratio shows that a considerable part of the cross section arises from transversely polarized photons. Spin density matrix elements are derived and presented in projections of Q2 or ‑ t‧. Violation of s-channel helicity conservation is observed for some of these elements. A sizable contribution from unnatural-parity-exchange amplitudes is found and the phase shift between those amplitudes that describe transverse ω production by longitudinal and transverse virtual photons is determined for the first time. Good agreement is found between the HERMES proton data and results of a pQCD-inspired phenomenological model that includes pion-pole contributions.

  17. Trace Element Geochemistry of Matrix Glass from the Bedout Impact Structure,Canning Basin NW Australia

    NASA Astrophysics Data System (ADS)

    Poreda, R. J.; Basu, A. R.; Chakrabarti, R.; Becker, L.

    2004-12-01

    We report on geochemical and petrographic analysis of separated matrix glass from Lagrange-1 and Bedout-1 drill cores that penetrated the Bedout structure offshore NW Australia. The results support the conclusion that the Bedout structure was produced by a a major ET impact at the end-Permian that generated shock melted glass and impact breccias (Becker et al., Science, v.304, p.1469, 2004) The Bedout structure is a 30 km, circular, 1.5 km uplifted basment high that occurs on the passive margin offshore NW Australia. The isolated feature, covered by 3 km of Triassic to Recent sediments,is not consistent with any typical volcanic province (i.e. arc or hotspot volcanism). This hypothesis is supported by the unique mineralogy and chemistry of the matrix glass. At Lagrange, major elements crudely resemble low-K, Fe-Ti basalts while the trace element patterns have two distinct signatures. The lower 250 m of Lagrange (3260 - 3010 m depth) have essentially flat REE and "spider" patterns that superficially resemble some E-MORB; a signal not typically found in arc, hotspot or continental margin settings. The upper 150 meters (3000 - 2850m) of Lagrange and the entire Bedout core (3030 - 3070m) have similar light REE-enriched patterns but low levels of alkalis, alkaline-earths and high field strength elements. Again, the chemistry is not consistent with an arc or hotspot setting, based on the low Ba and extremely low Sr (30-110 ppm) concentrations. Based on the geophysical, chemical and petrologic evidence, we hypothesize that the Bedout structure formed as the result` of an ET impact with Permian age rift margin basalts and continental sediment. The basalts did not completely melt as evidenced by the abundance of large (1 mm) An50 plagioclase,that exist as both crystalline plag and shock melted maskelynite. Plagioclase is the major repository of Sr in basalts and the lack of a plagioclase contribution to the melt glass is reflected in the low Sr abundance. Shock

  18. Potential sources of analytical bias and error in selected trace element data-quality analyses

    USGS Publications Warehouse

    Paul, Angela P.; Garbarino, John R.; Olsen, Lisa D.; Rosen, Michael R.; Mebane, Christopher A.; Struzeski, Tedmund M.

    2016-09-28

    Potential sources of analytical bias and error associated with laboratory analyses for selected trace elements where concentrations were greater in filtered samples than in paired unfiltered samples were evaluated by U.S. Geological Survey (USGS) Water Quality Specialists in collaboration with the USGS National Water Quality Laboratory (NWQL) and the Branch of Quality Systems (BQS).Causes for trace-element concentrations in filtered samples to exceed those in associated unfiltered samples have been attributed to variability in analytical measurements, analytical bias, sample contamination either in the field or laboratory, and (or) sample-matrix chemistry. These issues have not only been attributed to data generated by the USGS NWQL but have been observed in data generated by other laboratories. This study continues the evaluation of potential analytical bias and error resulting from matrix chemistry and instrument variability by evaluating the performance of seven selected trace elements in paired filtered and unfiltered surface-water and groundwater samples collected from 23 sampling sites of varying chemistries from six States, matrix spike recoveries, and standard reference materials.Filtered and unfiltered samples have been routinely analyzed on separate inductively coupled plasma-mass spectrometry instruments. Unfiltered samples are treated with hydrochloric acid (HCl) during an in-bottle digestion procedure; filtered samples are not routinely treated with HCl as part of the laboratory analytical procedure. To evaluate the influence of HCl on different sample matrices, an aliquot of the filtered samples was treated with HCl. The addition of HCl did little to differentiate the analytical results between filtered samples treated with HCl from those samples left untreated; however, there was a small, but noticeable, decrease in the number of instances where a particular trace-element concentration was greater in a filtered sample than in the associated

  19. Matrix elements in the coupled-cluster approach - With application to low-lying states in Li

    NASA Technical Reports Server (NTRS)

    Martensson-Pendrill, Ann-Marie; Ynnerman, Anders

    1990-01-01

    A procedure is suggested for evaluating matrix elements of an operator between wavefunctions in the coupled-cluster form. The use of the exponential ansatz leads to compact exponential expressions also for matrix elements. Algorithms are developed for summing all effects of one-particle clusters and certain chains of two-particle clusters (containing the well-known random-phase approximation as a subset). The treatment of one-particle perturbations in single valence states is investigated in detail. As examples the oscillator strength for the 2s-2p transition in Li as well as the hyperfine structure for the two states are studied and compared to earlier work.

  20. Elastic-plastic finite element analyses of an unidirectional, 9 vol percent tungsten fiber reinforced copper matrix composite

    NASA Technical Reports Server (NTRS)

    Sanfeliz, Jose G.

    1993-01-01

    Micromechanical modeling via elastic-plastic finite element analyses were performed to investigate the effects that the residual stresses and the degree of matrix work hardening (i.e., cold-worked, annealed) have upon the behavior of a 9 vol percent, unidirectional W/Cu composite, undergoing tensile loading. The inclusion of the residual stress-containing state as well as the simulated matrix material conditions proved to be significant since the Cu matrix material exhibited plastic deformation, which affected the subsequent tensile response of the composite system. The stresses generated during cooldown to room temperature from the manufacturing temperature were more of a factor on the annealed-matrix composite, since they induced the softened matrix to plastically flow. This event limited the total load-carrying capacity of this matrix-dominated, ductile-ductile type material system. Plastic deformation of the hardened-matrix composite during the thermal cooldown stage was not considerable, therefore, the composite was able to sustain a higher stress before showing any appreciable matrix plasticity. The predicted room temperature, stress-strain response, and deformation stages under both material conditions represented upper and lower bounds characteristic of the composite's tensile behavior. The initial deformation stage for the hardened material condition showed negligible matrix plastic deformation while for the annealed state, its initial deformation stage showed extensive matrix plasticity. Both material conditions exhibited a final deformation stage where the fiber and matrix were straining plastically. The predicted stress-strain results were compared to the experimental, room temperature, tensile stress-strain curve generated from this particular composite system. The analyses indicated that the actual thermal-mechanical state of the composite's Cu matrix, represented by the experimental data, followed the annealed material condition.

  1. LATTICE MATRIX ELEMENTS AND CP VIOLATION IN B AND KA PHYSICS: STATUS AND OUTLOOK.

    SciTech Connect

    SONI,A.

    2003-01-03

    Status of lattice calculations of hadron matrix elements along with CP violation in B and in K systems is reviewed. Lattice has provided useful input which, in conjunction with experimental data, leads to the conclusion that CP-odd phase in the CKM matrix plays the dominant role in the observed asymmetry in B {yields} {psi}K{sub s}. It is now quite likely that any beyond the SM, CP-odd, phase will cause only small deviations in B-physics. Search for the effects of the new phase(s) will consequently require very large data samples as well as very precise theoretical predictions. Clean determination of all the angles of the unitarity triangle therefore becomes essential. In this regard B {yields} KD{sup 0} processes play a unique role. Regarding K-decays, remarkable progress made by theory with regard to maintenance of chiral symmetry on the lattice is briefly discussed. First application already provide quantitative information on B{sub K} and the {Delta}I = 1/2 rule. The enhancement in ReA{sub 0} appears to arise solely from tree operators, esp. Q{sub 2}; penguin contribution to ReA{sub 0} appears to be very small. However, improved calculations are necessary for {epsilon}{prime}/{epsilon} as there the contributions of QCD penguins and electroweak penguins largely seem to cancel. There are good reasons, though, to believe that these cancellations will not survive improvements that are now underway. Importance of determining the unitarity triangle purely from K-decays is also emphasized.

  2. Potentially toxic element release by fenton oxidation of sewage sludge.

    PubMed

    Andrews, J P; Asaadi, M; Clarke, B; Ouki, S

    2006-01-01

    The presence, in sewage sludge, of excess levels of the potentially toxic elements (PTE) copper, zinc, chromium, cadmium, nickel, lead and mercury, could impact on our ability to recycle these residues in the future. Far stricter limits on the levels of PTEs are likely in proposed legislation. A method involving the dosing of Fenton's reagent, a mixture of ferrous iron and hydrogen peroxide, under acidic conditions was evaluated for its potential to reduce metal levels. The [Fe]:[H2O2] (w/w) ratio was found to give a good indication of the percentage copper and zinc elution obtainable. Sites with no iron dosing as part of wastewater treatment required extra iron to be added in order to initiate the Fenton's reaction. A significant reduction, in excess of 70%, of the copper and zinc was eluted from both raw primary and activated sludge solid fractions. Cadmium and nickel could be reduced to below detection limits but elution of mercury, lead and chromium was less than 40%. The iron catalyst concentration was found to be a crucial parameter. This process has the potential to reduce the heavy metal content of the sludge and allow the recycling of sludge to continue in a sustainable manner. PMID:17087386

  3. Characterization of metal matrix composites by linear ultrasonics and finite element modeling.

    PubMed

    Chen, Xuesheng; Sharples, Steve D; Clark, Matt; Wright, David

    2013-02-01

    Titanium metal matrix composites (TiMMCs) offer advantages over traditional materials for aerospace applications due to the increased mechanical strength of the materials. But the non-destructive inspection of these materials, especially with ultrasound, is in an infancy stage. If the manufacturing process of TiMMC is not correctly controlled, then disbonds and voids between the fibers can result. The effective microstructure of the composite makes difficulty to interpret results from traditional ultrasound techniques because of the scattering caused by fibers; the scattering prevents the ultrasound from penetrating far into the composite region and produces a background signal masking any reflections from voids. In this paper, relatively low frequency ultrasound is used to probe the composite region, and the state of the composite (porosity) is inferred from the velocity of the ultrasound traversing the composite. The relationship between the velocity and porosity is complex in this regime, so finite element (FE) analysis is used to model the composite regions and relate the velocity to the porosity. The FE simulated results are validated by ultrasound velocity measurements. PMID:23363095

  4. Calculating three loop ladder and V-topologies for massive operator matrix elements by computer algebra

    NASA Astrophysics Data System (ADS)

    Ablinger, J.; Behring, A.; Blümlein, J.; De Freitas, A.; von Manteuffel, A.; Schneider, C.

    2016-05-01

    Three loop ladder and V-topology diagrams contributing to the massive operator matrix element AQg are calculated. The corresponding objects can all be expressed in terms of nested sums and recurrences depending on the Mellin variable N and the dimensional parameter ε. Given these representations, the desired Laurent series expansions in ε can be obtained with the help of our computer algebra toolbox. Here we rely on generalized hypergeometric functions and Mellin-Barnes representations, on difference ring algorithms for symbolic summation, on an optimized version of the multivariate Almkvist-Zeilberger algorithm for symbolic integration, and on new methods to calculate Laurent series solutions of coupled systems of differential equations. The solutions can be computed for general coefficient matrices directly for any basis also performing the expansion in the dimensional parameter in case it is expressible in terms of indefinite nested product-sum expressions. This structural result is based on new results of our difference ring theory. In the cases discussed we deal with iterative sum- and integral-solutions over general alphabets. The final results are expressed in terms of special sums, forming quasi-shuffle algebras, such as nested harmonic sums, generalized harmonic sums, and nested binomially weighted (cyclotomic) sums. Analytic continuations to complex values of N are possible through the recursion relations obeyed by these quantities and their analytic asymptotic expansions. The latter lead to a host of new constants beyond the multiple zeta values, the infinite generalized harmonic and cyclotomic sums in the case of V-topologies.

  5. Symmetry of Isoscalar Matrix Elements and Systematics in the sd and beginning of fp shells

    NASA Astrophysics Data System (ADS)

    Orce, J. N.; Petkov, P.; Velázquez, V.; McKay, C. J.; Lesher, S. R.; Choudry, S.; Mynk, M.; Linnemann, A.; Jolie, J.; von Brentano, P.; Werner, V.; Yates, S. W.; McEllistrem, M. T.

    2006-03-01

    A careful determination of the lifetime and measurement of the branching ratio for decay of the first 2T=1+ state in 42Sc has allowed an accurate experimental test of charge independence in the A = 42 isobaric triplet. A lifetime of 69(17) fs was measured at the University of Kentucky, while relative intensities for the 975 keV and 1586 keV transitions depopulating the first 2T=1+ state have been determined at the University of Cologne as 100(1) and 8(1), respectively. Both measurements give an isoscalar matrix element, M0, of 6.4(9) (W.u.)1/2. This result confirms charge independence for the A=42 isobaric triplet. Shell model calculations have been carried out for understanding the global trend of M0 values for A = 4n + 2 isobaric triplets ranging from A = 18 to A = 42. The 21 (T=1)+ → 01 (T=1)+ transition energies, reduced transition probabilities and M0 values are reproduced to a high degree of accuracy. The trend of M0 strength along the sd shell is interpreted in terms of the shell structure. Certain discrepancies arise at the extremes of the sd shell, for the A = 18 and A = 38 isobaric triplets, which might be explained in terms of the low valence space at the extremes of the sd shell.

  6. A measurement of the top quark mass with a matrix element method

    SciTech Connect

    Gibson, Adam Paul

    2006-01-01

    The authors present a measurement of the mass of the top quark. The event sample is selected from proton-antiproton collisions, at 1.96 TeV center-of-mass energy, observed with the CDF detector at Fermilab's Tevatron. They consider a 318 pb-1 dataset collected between March 2002 and August 2004. They select events that contain one energetic lepton, large missing transverse energy, exactly four energetic jets, and at least one displaced vertex b tag. The analysis uses leading-order t$\\bar{t}$ and background matrix elements along with parameterized parton showering to construct event-by-event likelihoods as a function of top quark mass. From the 63 events observed with the 318 pb-1 dataset they extract a top quark mass of 172.0 ± 2.6(stat) ± 3.3(syst) GeV/c2 from the joint likelihood. The mean expected statistical uncertainty is 3.2 GeV/c2 for m $\\bar{t}$ = 178 GTeV/c2 and 3.1 GeV/c2 for m $\\bar{t}$ = 172.5 GeV/c2. The systematic error is dominated by the uncertainty of the jet energy scale.

  7. Theoretical uncertainties in the nuclear matrix elements of neutrinoless double beta decay: The transition operator

    SciTech Connect

    Menéndez, Javier

    2013-12-30

    We explore the theoretical uncertainties related to the transition operator of neutrinoless double-beta (0νββ) decay. The transition operator used in standard calculations is a product of one-body currents, that can be obtained phenomenologically as in Tomoda [1] or Šimkovic et al. [2]. However, corrections to the operator are hard to obtain in the phenomenological approach. Instead, we calculate the 0νββ decay operator in the framework of chiral effective theory (EFT), which gives a systematic order-by-order expansion of the transition currents. At leading orders in chiral EFT we reproduce the standard one-body currents of Refs. [1] and [2]. Corrections appear as two-body (2b) currents predicted by chiral EFT. We compute the effects of the leading 2b currents to the nuclear matrix elements of 0νββ decay for several transition candidates. The 2b current contributions are related to the quenching of Gamow-Teller transitions found in nuclear structure calculations.

  8. Characterization of metal matrix composites by linear ultrasonics and finite element modeling.

    PubMed

    Chen, Xuesheng; Sharples, Steve D; Clark, Matt; Wright, David

    2013-02-01

    Titanium metal matrix composites (TiMMCs) offer advantages over traditional materials for aerospace applications due to the increased mechanical strength of the materials. But the non-destructive inspection of these materials, especially with ultrasound, is in an infancy stage. If the manufacturing process of TiMMC is not correctly controlled, then disbonds and voids between the fibers can result. The effective microstructure of the composite makes difficulty to interpret results from traditional ultrasound techniques because of the scattering caused by fibers; the scattering prevents the ultrasound from penetrating far into the composite region and produces a background signal masking any reflections from voids. In this paper, relatively low frequency ultrasound is used to probe the composite region, and the state of the composite (porosity) is inferred from the velocity of the ultrasound traversing the composite. The relationship between the velocity and porosity is complex in this regime, so finite element (FE) analysis is used to model the composite regions and relate the velocity to the porosity. The FE simulated results are validated by ultrasound velocity measurements.

  9. Automated evaluation of matrix elements between contracted wavefunctions: A Mathematica version of the FRODO program

    NASA Astrophysics Data System (ADS)

    Angeli, C.; Cimiraglia, R.

    2013-02-01

    A symbolic program performing the Formal Reduction of Density Operators (FRODO), formerly developed in the MuPAD computer algebra system with the purpose of evaluating the matrix elements of the electronic Hamiltonian between internally contracted functions in a complete active space (CAS) scheme, has been rewritten in Mathematica. New version : A program summaryProgram title: FRODO Catalogue identifier: ADV Y _v2_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADVY_v2_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 3878 No. of bytes in distributed program, including test data, etc.: 170729 Distribution format: tar.gz Programming language: Mathematica Computer: Any computer on which the Mathematica computer algebra system can be installed Operating system: Linux Classification: 5 Catalogue identifier of previous version: ADV Y _v1_0 Journal reference of previous version: Comput. Phys. Comm. 171(2005)63 Does the new version supersede the previous version?: No Nature of problem. In order to improve on the CAS-SCF wavefunction one can resort to multireference perturbation theory or configuration interaction based on internally contracted functions (ICFs) which are obtained by application of the excitation operators to the reference CAS-SCF wavefunction. The previous formulation of such matrix elements in the MuPAD computer algebra system, has been rewritten using Mathematica. Solution method: The method adopted consists in successively eliminating all occurrences of inactive orbital indices (core and virtual) from the products of excitation operators which appear in the definition of the ICFs and in the electronic Hamiltonian expressed in the second quantization formalism. Reasons for new version: Some years ago we published in this journal a couple of papers [1, 2

  10. Automated evaluation of matrix elements between contracted wavefunctions: A Mathematica version of the FRODO program

    NASA Astrophysics Data System (ADS)

    Angeli, C.; Cimiraglia, R.

    2013-02-01

    A symbolic program performing the Formal Reduction of Density Operators (FRODO), formerly developed in the MuPAD computer algebra system with the purpose of evaluating the matrix elements of the electronic Hamiltonian between internally contracted functions in a complete active space (CAS) scheme, has been rewritten in Mathematica. New version : A program summaryProgram title: FRODO Catalogue identifier: ADV Y _v2_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADVY_v2_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 3878 No. of bytes in distributed program, including test data, etc.: 170729 Distribution format: tar.gz Programming language: Mathematica Computer: Any computer on which the Mathematica computer algebra system can be installed Operating system: Linux Classification: 5 Catalogue identifier of previous version: ADV Y _v1_0 Journal reference of previous version: Comput. Phys. Comm. 171(2005)63 Does the new version supersede the previous version?: No Nature of problem. In order to improve on the CAS-SCF wavefunction one can resort to multireference perturbation theory or configuration interaction based on internally contracted functions (ICFs) which are obtained by application of the excitation operators to the reference CAS-SCF wavefunction. The previous formulation of such matrix elements in the MuPAD computer algebra system, has been rewritten using Mathematica. Solution method: The method adopted consists in successively eliminating all occurrences of inactive orbital indices (core and virtual) from the products of excitation operators which appear in the definition of the ICFs and in the electronic Hamiltonian expressed in the second quantization formalism. Reasons for new version: Some years ago we published in this journal a couple of papers [1, 2

  11. Green's functions and matrix elements in the Furry picture for the electroweak theory with a non-Abelian external field

    NASA Astrophysics Data System (ADS)

    Gavrilov, S. P.; Gitman, D. M.

    1993-05-01

    We obtain explict expressions of all types of Green's functions in the Furry picture of the electroweak theory with a free, non-Abelian external field, by solving the corresponding one-particle equations. We also give the expressions for the matrix elements of simple processes in an external field.

  12. A comparison of measured and calculated thermal stresses in a hybrid metal matrix composite spar cap element

    NASA Technical Reports Server (NTRS)

    Jenkins, J. M.; Taylor, A. H.; Sakata, I. F.

    1985-01-01

    A hybrid spar of titanium with an integrally brazed composite, consisting of an aluminum matrix reinforced with boron-carbide-coated fibers, was heated in an oven and the resulting thermal stresses were measured. Uniform heating of the spar in an oven resulted in thermal stresses arising from the effects of dissimilar materials and anisotropy of the metal matrix composite. Thermal stresses were calculated from a finite element structural model using anisotropic material properties deduced from constituent properties and rules of mixtures. Comparisons of calculated thermal stresses with measured thermal stresses on the spar are presented. It was shown that failure to account for anisotropy in the metal matrix composite elements would result in large errors in correlating measured and calculated thermal stresses. It was concluded that very strong material characterization efforts are required to predict accurate thermal stresses in anisotropic composite structures.

  13. Electronic coupling matrix elements from charge constrained density functional theory calculations using a plane wave basis set

    NASA Astrophysics Data System (ADS)

    Oberhofer, Harald; Blumberger, Jochen

    2010-12-01

    We present a plane wave basis set implementation for the calculation of electronic coupling matrix elements of electron transfer reactions within the framework of constrained density functional theory (CDFT). Following the work of Wu and Van Voorhis [J. Chem. Phys. 125, 164105 (2006)], the diabatic wavefunctions are approximated by the Kohn-Sham determinants obtained from CDFT calculations, and the coupling matrix element calculated by an efficient integration scheme. Our results for intermolecular electron transfer in small systems agree very well with high-level ab initio calculations based on generalized Mulliken-Hush theory, and with previous local basis set CDFT calculations. The effect of thermal fluctuations on the coupling matrix element is demonstrated for intramolecular electron transfer in the tetrathiafulvalene-diquinone (Q-TTF-Q-) anion. Sampling the electronic coupling along density functional based molecular dynamics trajectories, we find that thermal fluctuations, in particular the slow bending motion of the molecule, can lead to changes in the instantaneous electron transfer rate by more than an order of magnitude. The thermal average, ( {< {| {H_ab } |^2 } > } )^{1/2} = 6.7 {mH}, is significantly higher than the value obtained for the minimum energy structure, | {H_ab } | = 3.8 {mH}. While CDFT in combination with generalized gradient approximation (GGA) functionals describes the intermolecular electron transfer in the studied systems well, exact exchange is required for Q-TTF-Q- in order to obtain coupling matrix elements in agreement with experiment (3.9 mH). The implementation presented opens up the possibility to compute electronic coupling matrix elements for extended systems where donor, acceptor, and the environment are treated at the quantum mechanical (QM) level.

  14. An Investigation of Reliability Models for Ceramic Matrix Composites and their Implementation into Finite Element Codes

    NASA Technical Reports Server (NTRS)

    Duffy, Stephen F.

    1998-01-01

    The development of modeling approaches for the failure analysis of ceramic-based material systems used in high temperature environments was the primary objective of this research effort. These materials have the potential to support many key engineering technologies related to the design of aeropropulsion systems. Monolithic ceramics exhibit a number of useful properties such as retention of strength at high temperatures, chemical inertness, and low density. However, the use of monolithic ceramics has been limited by their inherent brittleness and a large variation in strength. This behavior has motivated material scientists to reinforce the monolithic material with a ceramic fiber. The addition of a second ceramic phase with an optimized interface increases toughness and marginally increases strength. The primary purpose of the fiber is to arrest crack growth, not to increase strength. The material systems of interest in this research effort were laminated ceramic matrix composites, as well as two- and three- dimensional fabric reinforced ceramic composites. These emerging composite systems can compete with metals in many demanding applications. However, the ongoing metamorphosis of ceramic composite material systems, and the lack of standardized design data has in the past tended to minimize research efforts related to structural analysis. Many structural components fabricated from ceramic matrix composites (CMC) have been designed by "trial and error." The justification for this approach lies in the fact that during the initial developmental phases for a material system fabrication issues are paramount. Emphasis is placed on demonstrating feasibility rather than fully understanding the processes controlling mechanical behavior. This is understandable during periods of rapid improvements in material properties for any composite system. But to avoid the ad hoc approach, the analytical methods developed under this effort can be used to develop rational structural

  15. Trajectories of S-matrix poles in a new finite-range potential

    SciTech Connect

    Racz, A.; Salamon, P.; Vertse, T.

    2011-09-15

    The trajectories of S-matrix poles are calculated in the finite-range phenomenological potential introduced recently by Salamon and Vertse [Phys. Rev. C 77, 037302 (2008)] (SV). The potential is similar to a Woods-Saxon (WS) interaction, but it is exactly zero beyond a radius, without any cutoff. The trajectories of the resonance poles in this SV potential are compared to the corresponding trajectories in a cutoff WS potential for l>0. The dependence on the cutoff radius is demonstrated. The starting points of the trajectories turn out to be related to the average ranges of the two terms in the SV potential.

  16. Assessment of a hybrid finite element-transfer matrix model for flat structures with homogeneous acoustic treatments.

    PubMed

    Alimonti, Luca; Atalla, Noureddine; Berry, Alain; Sgard, Franck

    2014-05-01

    Modeling complex vibroacoustic systems including poroelastic materials using finite element based methods can be unfeasible for practical applications. For this reason, analytical approaches such as the transfer matrix method are often preferred to obtain a quick estimation of the vibroacoustic parameters. However, the strong assumptions inherent within the transfer matrix method lead to a lack of accuracy in the description of the geometry of the system. As a result, the transfer matrix method is inherently limited to the high frequency range. Nowadays, hybrid substructuring procedures have become quite popular. Indeed, different modeling techniques are typically sought to describe complex vibroacoustic systems over the widest possible frequency range. As a result, the flexibility and accuracy of the finite element method and the efficiency of the transfer matrix method could be coupled in a hybrid technique to obtain a reduction of the computational burden. In this work, a hybrid methodology is proposed. The performances of the method in predicting the vibroacoutic indicators of flat structures with attached homogeneous acoustic treatments are assessed. The results prove that, under certain conditions, the hybrid model allows for a reduction of the computational effort while preserving enough accuracy with respect to the full finite element solution.

  17. Constrained positive matrix factorization: Elemental ratios, spatial distinction, and chemical transport model source contributions

    NASA Astrophysics Data System (ADS)

    Sturtz, Timothy M.

    Source apportionment models attempt to untangle the relationship between pollution sources and the impacts at downwind receptors. Two frameworks of source apportionment models exist: source-oriented and receptor-oriented. Source based apportionment models use presumed emissions and atmospheric processes to estimate the downwind source contributions. Conversely, receptor based models leverage speciated concentration data from downwind receptors and apply statistical methods to predict source contributions. Integration of both source-oriented and receptor-oriented models could lead to a better understanding of the implications sources have on the environment and society. The research presented here investigated three different types of constraints applied to the Positive Matrix Factorization (PMF) receptor model within the framework of the Multilinear Engine (ME-2): element ratio constraints, spatial separation constraints, and chemical transport model (CTM) source attribution constraints. PM10-2.5 mass and trace element concentrations were measured in Winston-Salem, Chicago, and St. Paul at up to 60 sites per city during two different seasons in 2010. PMF was used to explore the underlying sources of variability. Information on previously reported PM10-2.5 tire and brake wear profiles were used to constrain these features in PMF by prior specification of selected species ratios. We also modified PMF to allow for combining the measurements from all three cities into a single model while preserving city-specific soil features. Relatively minor differences were observed between model predictions with and without the prior ratio constraints, increasing confidence in our ability to identify separate brake wear and tire wear features. Using separate data, source contributions to total fine particle carbon predicted by a CTM were incorporated into the PMF receptor model to form a receptor-oriented hybrid model. The level of influence of the CTM versus traditional PMF was

  18. Reanalysis of nuclear spin matrix elements for dark matter spin-dependent scattering

    NASA Astrophysics Data System (ADS)

    Cannoni, M.

    2013-04-01

    We show how to include in the existing calculations for nuclei other than Xe129 and Xe131 the corrections to the isovector coupling arising in chiral effective field theory recently found in Menendez et al. [Phys. Rev. D 86, 103511 (2012)PRVDAQ1550-7998]. The dominant, momentum-independent, two-body current effect can be taken into account by formally redefining the static spin matrix elements ⟨Sp,n⟩. By further using the normalized form factor at q≠0 built with the one-body level structure functions, we show that the weakly interacting massive particles (WIMP)-nucleus cross section and the upper limits on the WIMP-nucleon cross sections coincide with the ones derived by using the exact functions at the two-body level. We explicitly show it in the case of XENON100 limits on the WIMP-neutron cross section, and we recalculate the limits on the WIMP-proton spin-dependent cross section set by COUPP. We also give practical formulas to obtain ⟨Sp,n⟩ given the structure functions in the various formalisms and notations existing in the literature. We argue that the standard treatment of the spin-dependent cross section in terms of three independent isospin functions, S00(q), S11(q), and S01(q), is redundant in the sense that the interference function S01(q) is the double product |S01(q)|=2S00(q)S11(q) even when including the new effective field theory corrections.

  19. Cancer Cell Stiffness: Integrated Roles of Three-Dimensional Matrix Stiffness and Transforming Potential

    PubMed Central

    Baker, Erin L.; Lu, Jing; Yu, Dihua; Bonnecaze, Roger T.; Zaman, Muhammad H.

    2010-01-01

    While significant advances have been made toward revealing the molecular mechanisms that influence breast cancer progression, much less is known about the associated cellular mechanical properties. To this end, we use particle-tracking microrheology to investigate the interplay among intracellular mechanics, three-dimensional matrix stiffness, and transforming potential in a mammary epithelial cell (MEC) cancer progression series. We use a well-characterized model system where human-derived MCF10A MECs overexpress either ErbB2, 14-3-3ζ, or both ErbB2 and 14-3-3ζ, with empty vector as a control. Our results show that MECs possessing ErbB2 transforming potential stiffen in response to elevated matrix stiffness, whereas non-transformed MECs or those overexpressing only 14-3-3ζ do no exhibit this response. We further observe that overexpression of ErbB2 alone is associated with the highest degree of intracellular sensitivity to matrix stiffness, and that the effect of transforming potential on intracellular stiffness is matrix-stiffness-dependent. Moreover, our intracellular stiffness measurements parallel cell migration behavior that has been previously reported for these MEC sublines. Given the current knowledge base of breast cancer mechanobiology, these findings suggest that there may be a positive relationship among intracellular stiffness sensitivity, cell motility, and perturbed mechanotransduction in breast cancer. PMID:20923638

  20. Cancer cell stiffness: integrated roles of three-dimensional matrix stiffness and transforming potential.

    PubMed

    Baker, Erin L; Lu, Jing; Yu, Dihua; Bonnecaze, Roger T; Zaman, Muhammad H

    2010-10-01

    While significant advances have been made toward revealing the molecular mechanisms that influence breast cancer progression, much less is known about the associated cellular mechanical properties. To this end, we use particle-tracking microrheology to investigate the interplay among intracellular mechanics, three-dimensional matrix stiffness, and transforming potential in a mammary epithelial cell (MEC) cancer progression series. We use a well-characterized model system where human-derived MCF10A MECs overexpress either ErbB2, 14-3-3ζ, or both ErbB2 and 14-3-3ζ, with empty vector as a control. Our results show that MECs possessing ErbB2 transforming potential stiffen in response to elevated matrix stiffness, whereas non-transformed MECs or those overexpressing only 14-3-3ζ do no exhibit this response. We further observe that overexpression of ErbB2 alone is associated with the highest degree of intracellular sensitivity to matrix stiffness, and that the effect of transforming potential on intracellular stiffness is matrix-stiffness-dependent. Moreover, our intracellular stiffness measurements parallel cell migration behavior that has been previously reported for these MEC sublines. Given the current knowledge base of breast cancer mechanobiology, these findings suggest that there may be a positive relationship among intracellular stiffness sensitivity, cell motility, and perturbed mechanotransduction in breast cancer.

  1. Direct measurement of excited-state dipole matrix elements using electromagnetically induced transparency in the hyperfine Paschen-Back regime

    NASA Astrophysics Data System (ADS)

    Whiting, Daniel J.; Keaveney, James; Adams, Charles S.; Hughes, Ifan G.

    2016-04-01

    Applying large magnetic fields to gain access to the hyperfine Paschen-Back regime can isolate three-level systems in a hot alkali metal vapors, thereby simplifying usually complex atom-light interactions. We use this method to make the first direct measurement of the |<5 P ||e r ||5 D >| matrix element in 87Rb. An analytic model with only three levels accurately models the experimental electromagnetically induced transparency spectra and extracted Rabi frequencies are used to determine the dipole matrix element. We measure |<5 P3 /2||e r ||5 D5 /2>| =(2.290 ±0 .002stat±0 .04syst) e a0 , which is in excellent agreement with the theoretical calculations of Safronova, Williams, and Clark [Phys. Rev. A 69, 022509 (2004), 10.1103/PhysRevA.69.022509].

  2. Expressions for the second-order mixed partial derivatives of Slater-Koster matrix elements at spherical coordinate singularities

    NASA Astrophysics Data System (ADS)

    Meister, Matthias

    2005-10-01

    In a recent publication it has been shown how to generate derivatives with respect to atom coordinates of Slater-Koster matrix elements for the tight binding modeling of a system. For the special case of a mixed second partial derivative at coordinate singularities only the results were stated in that publication. In this work, the derivation of these results is given in detail. Though it may seem rather technical and only applicable to a very special case, atomic configurations where the connecting vector between the two atoms involved in a two-center matrix element is aligned along the z axis (in the usual approach) require results for precisely this case. The expressions derived in this work have been implemented in the DINAMO code.

  3. Diagnosis potential of near infrared Mueller Matrix imaging for colonic adenocarcinoma

    NASA Astrophysics Data System (ADS)

    Wang, Jianfeng; Zheng, Wei; Lin, Kan; Huang, Zhiwei

    2016-03-01

    Mueller matrix imaging along with polar decomposition method was employed for the colonic adenocarcinoma detection by polarized light in the near-infrared spectral range (700-1100 nm). A high-speed (<5s) Muller matrix imaging system with dual-rotating waveplates was developed. 16 (4 by 4) full Mueller matrices of the colonic tissues (i.e., normal and caner) were acquired. Polar decomposition was further implemented on the 16 images to derive the diattentuation, depolarization, and the retardance images. The decomposed images showed clear margin between the normal and adenocarcinomaous colon tissue samples. The work shows the potential of near-infrared Mueller matrix imaging for the early diagnosis and detection of malignant lesions in the colon.

  4. Identification of scaffold/Matrix Attachment (S/MAR) like DNA element from the gastrointestinal protozoan parasite Giardia lamblia

    PubMed Central

    2010-01-01

    Background Chromatin in the nucleus of all eukaryotes is organized into a system of loops and domains. These loops remain fastened at their bases to the fundamental framework of the nucleus, the matrix or the scaffold. The DNA sequences which anchor the bases of the chromatin loops to the matrix are known as Scaffold/Matrix Attachment Regions or S/MARs. Though S/MARs have been studied in yeast and higher eukaryotes and they have been found to be associated with gene organization and regulation of gene expression, they have not been reported in protists like Giardia. Several tools have been discovered and formulated to predict S/MARs from a genome of a higher eukaryote which take into account a number of features. However, the lack of a definitive consensus sequence in S/MARs and the randomness of the protozoan genome in general, make it a challenge to predict and identify such sequences from protists. Results Here, we have analysed the Giardia genome for the probable S/MARs predicted by the available computational tools; and then shown these sequences to be physically associated with the nuclear matrix. Our study also reflects that while no single computational tool is competent to predict such complex elements from protist genomes, a combination of tools followed by experimental verification is the only way to confirm the presence of these elements from these organisms. Conclusion This is the first report of S/MAR elements from the protozoan parasite Giardia lamblia. This initial work is expected to lay a framework for future studies relating to genome organization as well as gene regulatory elements in this parasite. PMID:20565887

  5. Analysis of the influence of external magnetic field on transition matrix elements in quantum well and quantum cascade laser structures

    NASA Astrophysics Data System (ADS)

    Demić, Aleksandar; Radovanović, Jelena; Milanović, Vitomir

    2016-08-01

    We present a method for modeling nonparabolicity effects (NPE) in quantum nanostructures in presence of external electric and magnetic field by using second order perturbation theory. The method is applied to analysis of quantum well structure and active region of a quantum cascade laser (QCL). This model will allow us to examine the influence of magnetic field on dipole matrix element in QCL structures, which will provide a better insight to how NPE can affect the gain of QCL structures.

  6. Land Application of Wastes: An Educational Program. Potentially Toxic Elements - Module 11.

    ERIC Educational Resources Information Center

    Clarkson, W. W.; And Others

    Five elements are identified as being potentially hazardous in this module. These are boron, cadmium, copper, molybdenum, and nickel. The hazards to plants and animals posed by these elements are discussed in some detail. The sources of toxic elements in sewage and the factors that effect the uptake of toxic elements by sewage sludge are also…

  7. FERM3D: A finite element R-matrix electron molecule scattering code

    NASA Astrophysics Data System (ADS)

    Tonzani, Stefano

    2007-01-01

    FERM3D is a three-dimensional finite element program, for the elastic scattering of a low energy electron from a general polyatomic molecule, which is converted to a potential scattering problem. The code is based on tricubic polynomials in spherical coordinates. The electron-molecule interaction is treated as a sum of three terms: electrostatic, exchange, and polarization. The electrostatic term can be extracted directly from ab initio codes ( GAUSSIAN 98 in the work described here), while the exchange term is approximated using a local density functional. A local polarization potential based on density functional theory [C. Lee, W. Yang, R.G. Parr, Phys. Rev. B 37 (1988) 785] describes the long range attraction to the molecular target induced by the scattering electron. Photoionization calculations are also possible and illustrated in the present work. The generality and simplicity of the approach is important in extending electron-scattering calculations to more complex targets than it is possible with other methods. Program summaryTitle of program:FERM3D Catalogue identifier:ADYL_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADYL_v1_0 Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland Computer for which the program is designed and others on which it has been tested:Intel Xeon, AMD Opteron 64 bit, Compaq Alpha Operating systems or monitors under which the program has been tested:HP Tru64 Unix v5.1, Red Hat Linux Enterprise 3 Programming language used:Fortran 90 Memory required to execute with typical data:900 MB (neutral CO 2), 2.3 GB (ionic CO 2), 1.4 GB (benzene) No. of bits in a word:32 No. of processors used:1 Has the code been vectorized?:No No. of lines in distributed program, including test data, etc.:58 383 No. of bytes in distributed program, including test data, etc.:561 653 Distribution format:tar.gzip file CPC Program library subprograms used:ADDA, ACDP Nature of physical problem:Scattering of an

  8. Superconducting axisymmetric finite elements based on a gauged potential variational principle. Part 1: Formulation

    NASA Technical Reports Server (NTRS)

    Schuler, James J.; Felippa, Carlos A.

    1994-01-01

    The present work is part of a research program for the numerical simulation of electromagnetic (EM) fields within conventional Ginzburg-Landau (GL) superconductors. The final goal of this research is to formulate, develop and validate finite element (FE) models that can accurately capture electromagnetic thermal and material phase changes in a superconductor. The formulations presented here are for a time-independent Ginzburg-Landau superconductor and are derived from a potential-based variational principle. We develop an appropriate variational formulation of time-independent supercontivity for the general three-dimensional case and specialize it to the one-dimensional case. Also developed are expressions for the material-dependent parameters alpha and beta of GL theory and their dependence upon the temperature T. The one-dimensional formulation is then discretized for finite element purposes and the first variation of these equations is obtained. The resultant Euler equations contain nonlinear terms in the primary variables. To solve these equations, an incremental-iterative solution method is used. Expressions for the internal force vector, external force vector, loading vector and tangent stiffness matrix are therefore developed for use with the solution procedure.

  9. The Dynamic Response of an Euler-Bernoulli Beam on an Elastic Foundation by Finite Element Analysis using the Exact Stiffness Matrix

    NASA Astrophysics Data System (ADS)

    Kim, Jeong Soo; Kyum Kim, Moon

    2012-08-01

    In this study, finite element analysis of beam on elastic foundation, which received great attention of researchers due to its wide applications in engineering, is performed for estimating dynamic responses of shallow foundation using exact stiffness matrix. First, element stiffness matrix based on the closed solution of beam on elastic foundation is derived. Then, we performed static finite element analysis included exact stiffness matrix numerically, comparing results from the analysis with some exact analysis solutions well known for verification. Finally, dynamic finite element analysis is performed for a shallow foundation structure under rectangular pulse loading using trapezoidal method. The dynamic analysis results exist in the reasonable range comparing solution of single degree of freedom problem under a similar condition. The results show that finite element analysis using exact stiffness matrix is evaluated as a good tool of estimating the dynamic response of structures on elastic foundation.

  10. Analytic structure of the multichannel Jost matrix for potentials with Coulombic tails

    SciTech Connect

    Rakityansky, S. A.; Elander, N.

    2013-12-15

    A quantum system is considered that can move in N two-body channels with the potentials that may include the Coulomb interaction. For this system, the Jost matrix is constructed in such a way that all its dependencies on the channel momenta and Sommerfeld parameters are factorized in the form of explicit analytic expressions. It is shown that the two remaining unknown matrices are single-valued analytic functions of the energy and therefore can be expanded in the Taylor series near an arbitrary point within the domain of their analyticity. It is derived a system of first-order differential equations whose solutions determine the expansion coefficients of these series. Alternatively, the unknown expansion coefficients can be used as fitting parameters for parametrizing experimental data similarly to the effective-range expansion. Such a parametrization has the advantage of preserving proper analytic structure of the Jost matrix and can be done not only near the threshold energies, but around any collision or even complex energy. As soon as the parameters are obtained, the Jost matrix (and therefore the S-matrix) is known analytically on all sheets of the Riemann surface, and thus enables one to locate possible resonances.

  11. Polydispersity for Tuning the Potential of Mean Force between Polymer Grafted Nanoparticles in a Polymer Matrix

    NASA Astrophysics Data System (ADS)

    Martin, Tyler B.; Dodd, Paul M.; Jayaraman, Arthi

    2013-01-01

    We present an integrated theory and simulation study of polydisperse polymer grafted nanoparticles in a polymer matrix to demonstrate the effect of polydispersity in graft length on the potential of mean force between the grafted nanoparticles. In dense polymer solutions, increasing polydispersity in graft length reduces the strength of repulsion at contact and weakens the attractive well at intermediate interparticle distances, completely eliminating the latter at high polydispersity index. The reduction in contact repulsion is attributable to polydispersity relieving monomer crowding near the particle surface, especially at high grafting densities. The elimination of the midrange attractive well is attributable to the longer grafts in the polydisperse graft length distribution that introduce longer range steric repulsion and alter the wetting of the grafted layer by matrix chains. Dispersion of the grafted particles is stabilized by increased penetration or wetting of the polydisperse grafted layer by the matrix chains. This work demonstrates that at high grafting densities, polydispersity in graft length can be used to stabilize dispersions of grafted nanoparticles in a polymer matrix at conditions where monodisperse grafts would cause aggregation.

  12. Elemental concentrations in Triticale straw, a potential bioenergy feedstock

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Triticale (X Triticosecale Wittmack) is produced on more than three million ha world wide including 344,000 ha in the USA. Straw resulting from triticale production could provide feedstock for bioenergy production in many regions of the world, but high concentrations of certain elements, including s...

  13. Potential inert matrix materials: Materials synthesis and evaluation of in-service engineering parameters

    NASA Astrophysics Data System (ADS)

    Xu, Peng

    Containing no fertile materials, inert matrix fuel (IMF) has been introduced as a potential transmutation solution for the increasing inventory of both weapon grade and reactor grade plutonium (Pu). In the present work, the MgO-pyrochlore (Nd2Zr2O7) composites and spinel magnesium stannate (Mg2SnO4) were selected as potential inert matrix (IM) materials. A comprehensive investigation was conducted on evaluation of the engineering parameters of the potential IM materials. The MgO-Nd2Zr2O7 composites and Mg 2SnO4 were fabricated through conventional solid state processing. The crystal structure and microstructure of the synthesized composites and Mg2SnO4 were studied. The irradiation tolerance of the potential IM materials was first assessed. The resistance of Mg2SnO 4 against irradiation induced amorphization was assessed experimentally using in situ TEM technique. The critical amorphization doses for Mg2SnO4 irradiated by 1 MeV Kr2+ ions were determined to be 5.5 dpa at 50 K and 11.0 dpa at 150 K, respectively. The obtained results were compared with other spinels especially MgAl 2O4, and the radiation tolerance of spinels were discussed. The next evaluation was water corrosion resistance of the potential IM materials. Homogeneous MgO-Nd2Zr2O7 composites exhibited an improved hydrothermal corrosion resistance than inhomogeneous composites and pure MgO. Even though spinel Mg2SnO4 was not stable in water at 300°C and saturation pressure, the corrosion was limited only to the surface, and the volume and mass changes were less than 1 % after 720 h corrosion. Feasibility of aqueous reprocessing was evaluated by studying the dissolution behavior of the potential IM materials in acidic solutions, with an emphasis on nitric acid. Dissolution of the MgO-Nd2Zr2O 7 composites in HNO3 resulted in a selective dissolution of MgO. Mechanical agitation such as magnetic bar stirring was necessary to achieve a completed dissolution of MgO and disintegration of porous Nd 2Zr2O7

  14. SevenOperators, a Mathematica script for harmonic oscillator nuclear matrix elements arising in semileptonic electroweak interactions

    NASA Astrophysics Data System (ADS)

    Haxton, Wick; Lunardini, Cecilia

    2008-09-01

    Semi-leptonic electroweak interactions in nuclei—such as β decay, μ capture, charged- and neutral-current neutrino reactions, and electron scattering—are described by a set of multipole operators carrying definite parity and angular momentum, obtained by projection from the underlying nuclear charge and three-current operators. If these nuclear operators are approximated by their one-body forms and expanded in the nucleon velocity through order |p→|/M, where p→ and M are the nucleon momentum and mass, a set of seven multipole operators is obtained. Nuclear structure calculations are often performed in a basis of Slater determinants formed from harmonic oscillator orbitals, a choice that allows translational invariance to be preserved. Harmonic-oscillator single-particle matrix elements of the multipole operators can be evaluated analytically and expressed in terms of finite polynomials in q, where q is the magnitude of the three-momentum transfer. While results for such matrix elements are available in tabular form, with certain restriction on quantum numbers, the task of determining the analytic form of a response function can still be quite tedious, requiring the folding of the tabulated matrix elements with the nuclear density matrix, and subsequent algebra to evaluate products of operators. Here we provide a Mathematica script for generating these matrix elements, which will allow users to carry out all such calculations by symbolic manipulation. This will eliminate the errors that may accompany hand calculations and speed the calculation of electroweak nuclear cross sections and rates. We illustrate the use of the new script by calculating the cross sections for charged- and neutral-current neutrino scattering in 12C. Program summaryProgram title: SevenOperators Catalogue identifier: AEAY_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEAY_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland

  15. The Conservation/Solution Element (STE) Method for Linear Potential Flow Problems

    NASA Technical Reports Server (NTRS)

    Adeyeye, John O.; Attia, Naguib F.; Jackson, Joy; Hunter, Timothy

    1996-01-01

    The potential equation is discretized on rectangular domains using the Conservation/Solution Element Method (STE) approach. Computational examples with a discussion of numerical experience gained are given.

  16. Time-dependent wave-packet method for the complete determination of S-matrix elements for reactive molecular collisions in three dimensions

    NASA Technical Reports Server (NTRS)

    Judson, Richard S.; Kouri, Donald J.; Neuhauser, Daniel; Baer, Michael

    1990-01-01

    An alternative time-dependent wave-packet method for treating three-dimensional gas phase reactive atom-diatom collisions is presented. The method employs a nonreactive body-frame wave packet propagation procedure, made possible by judicious use of absorbing optical potentials, a novel scheme for interpolating the wave function from coordinates in one arrangement to those in another and the fact that the time-dependent Schroedinger equation is an initial-value problem. The last feature makes possible a computationally viable and accurate procedure for changing from one arrangement's coordinates to another. In addition, the method allows the determination of S-matrix elements over a wide range of energies from a single wave-packet propagation. The method is illustrated by carrying out detailed calculations of inelastic and reactive scattering in the H + H2 system using the Liu-Siegbahn-Truhlar-Horowitz potential surface.

  17. Qualitative Analysis of Teeth and Evaluation of Amalgam Elements Penetration into Dental Matrix Using Laser Induced Breakdown Spectroscopy

    PubMed Central

    Gazmeh, Meisam; Bahreini, Maryam; Tavassoli, Seyed Hassan; Asnaashari, Mohammad

    2015-01-01

    Introduction: In this study, laser induced breakdown spectroscopy (LIBS) is used for qualitative analysis of healthy and carious teeth. The technique of laser ablation is receiving increasing attention for applications in dentistry, specifically for the treatment of teeth such as drilling of micro-holes and plaque removal. Methods: A quality-switched (Q-switched) Neodymium-Doped Yttrium Aluminium Garnet (Nd:YAG) laser operating at wavelength of 1064 nm, pulse energy of 90 mJ/pulse, repetition rate of 2Hz and pulse duration of 6 ns was used in this analysis. In the process of ablation a luminous micro-plasma is normally generated which may be exploited for on-line elemental analysis via laser induced breakdown spectroscopy technique. We propose laser induced breakdown spectroscopy as a rapid, in situ and easy method for monitoring drilling process. Results: The results of elemental analysis show the presence of some trace elements in teeth including P, Ca, Mg, Zn, K, Sr, C, Na, H, O and the permeability of some amalgam (teeth filling materials) elements including Hg, Ag, Cu and Sn into dental matrix. Conclusion: This study addresses the ability of LIBS in elemental analysis of teeth and its feasibility in acute identification of healthy and carious teeth during drilling process for future clinical applications. PMID:25987971

  18. Division of focal plane polarimeter-based 3 × 4 Mueller matrix microscope: a potential tool for quick diagnosis of human carcinoma tissues

    NASA Astrophysics Data System (ADS)

    Chang, Jintao; He, Honghui; Wang, Ye; Huang, Yi; Li, Xianpeng; He, Chao; Liao, Ran; Zeng, Nan; Liu, Shaoxiong; Ma, Hui

    2016-05-01

    A polarization microscope is a useful tool to reveal the optical anisotropic nature of a specimen and can provide abundant microstructural information about samples. We present a division of focal plane (DoFP) polarimeter-based polarization microscope capable of simultaneously measuring both the Stokes vector and the 3×4 Mueller matrix with an optimal polarization illumination scheme. The Mueller matrix images of unstained human carcinoma tissue slices show that the m24 and m34 elements can provide important information for pathological observations. The characteristic features of the m24 and m34 elements can be enhanced by polarization staining under illumination by a circularly polarized light. Hence, combined with a graphics processing unit acceleration algorithm, the DoFP polarization microscope is capable of real-time polarization imaging for potential quick clinical diagnoses of both standard and frozen slices of human carcinoma tissues.

  19. Transposable Element ‘roo’ Attaches to Nuclear Matrix of the Drosophila melanogaster

    PubMed Central

    Mamillapalli, Anitha; Pathak, Rashmi U.; Garapati, Hita S.; Mishra, Rakesh K.

    2013-01-01

    The genome of eukaryotes is organized into structural units of chromatin loops. This higher order organization is supported by a nuclear skeleton called the nuclear matrix. The genomic DNA associated with the nuclear matrix is called the matrix associated region (MAR). Only a few genome-wide screens have been attempted, although many studies have characterized locusspecific MAR DNA sequences. In this study, a MAR DNA library was prepared from the Drosophila melanogaster Meigen (Diptera: Drosophilidae) genome. One of the sequences identified as a MAR was from a long terminal repeat region of ‘roo’ retrotransposon (roo MAR). Sequence analysis of roo MAR showed its distribution across the D. melanogaster genome. roo MAR also showed high sequence similarity with a previously identified MAR in Drosophila, namely the ‘gypsy’ retrotransposon. Analysis of the genes flanking roo MAR insertions in the Drosophila genome showed that genes were co-ordinately expressed. The results from the present study in D. melanogaster suggest this sequence plays an important role in genome organization and function. The findings point to an evolutionary role of retrotransposons in shaping the genomic architecture of eukaryotes. PMID:24735214

  20. NUMEN Project @ LNS : Heavy ions double charge exchange reactions towards the 0νββ nuclear matrix element determination

    SciTech Connect

    Agodi, C. Calabretta, L.; Calanna, A.; Carbone, D.; Cavallaro, M.; Colonna, M.; Cuttone, G.; Finocchiaro, P.; Pandola, L.; Rifuggiato, D.; Tudisco, S.; Cappuzzello, F.; Greco, V.; Bonanno, D. L.; Bongiovanni, D. G.; Longhitano, F.; Branchina, V.; Foti, A.; Lo Presti, D.; Lanzalone, G.; and others

    2015-10-28

    In the NUMEN Project it is proposed an innovative technique to access the nuclear matrix elements entering in the expression of the life-time of the neutrinoless double beta decay, using relevant cross sections of double charge exchange reactions. A key aspect is the use of MAGNEX large acceptance magnetic spectrometer, for the detection of the ejectiles, and of the INFN Laboratori Nazionali del Sud (LNS) K800 Superconducting Cyclotron (CS), for the acceleration of the required high resolution and low emittance heavy-ion beams.

  1. The matrix effect of blueberry, oat meal and milk on polyphenols, antioxidant activity and potential bioavailability.

    PubMed

    Cebeci, Fatma; Şahin-Yeşilçubuk, Neşe

    2014-02-01

    In recent years, ready-to eat breakfast cereals prepared with fruit ingredients have gained particular attention due to their polyphenolic contents and health promoting effects. In this study, the matrix effect of blueberry, oat meal, whole milk or skimmed milk on polyphenols, antioxidative potential as well as their potential bioavailability were investigated. The phenolic properties of whole milk, skimmed milk, blueberry and oat meal were investigated and the changes in combinations of the ingredients were determined. Milk addition decreased the total phenolic, flavonoid and anthocyanin content of samples statistically and had negative effect on antioxidant activity showing differences among different methods. According to HPLC results, it was not possible to detect catechin in mixtures due to milk addition. In vitro digestion method was used to determine potential bioavailability of phenolic compounds. According to in vitro digestion procedure results, whole or skimmed milk did not affect the total phenolic content of the proportion passing to the blood from intestine.

  2. Calculation of Steady-state Evaporation for an Arbitrary Matrix Potential at Ground Surface

    NASA Astrophysics Data System (ADS)

    Liu, X.; Zhan, H.

    2014-12-01

    The water loss from soil by evaporation and the amount of ground water available to plants due to the upward movement of water from a water table is an important topic in many disciplines such as soil science, hydrology, and plant physiology. Although water evaporation in actual field setting is a highly complex process, a nearly steady upward flow from a water table to a bare soil surface may be established if the daily evaporative demand is reasonably uniform for a long period of time. While the maximum potential rate of evaporation from the ground surface depends on atmospheric conditions, the actual flux across the soil surface is limited by the ability of the porous medium for transmitting water from the unsaturated zone.The purpose of this study is to calculate the steady-state evaporation for an arbitrary matrix potential at bare soil surface above a shallow water table, while the unsaturated hydraulic conductivity is a nonlinear function of water content or matrix potential. The Haverkamp function and the Brooks-Corey function for the unsaturated hydraulic conductivity are used, and the study results are contrast among the solution developed from the two retention equation and HYDRUS simulation.

  3. R-matrix and Potential Model Extrapolations for NACRE Update and Extension Project

    NASA Astrophysics Data System (ADS)

    Aikawa, Masayuki; Arai, Koji; Katsuma, Masahiko; Takahashi, Kohji; Arnould, Marcel; Utsunomiya, Hiroaki

    2006-07-01

    NACRE, the `nuclear astrophysics compilation of reaction rates', has been widely utilized in stellar evolution and nucleosynthesis studies. Its update and extension programme started within a Konan-Université Libre de Bruxelles (ULB) collaboration. At the present moment, experimental data in refereed journals have been collected, and their theoretical extrapolations are being performed using the R-matrix or potential models. For the 3H(d,n)4He and 2H(p,γ)3He reactions, we present preliminary results that could well reproduce the experimental data.

  4. Fluorinated matrix metalloproteinases inhibitors--Phosphonate based potential probes for positron emission tomography.

    PubMed

    Beutel, Bernd; Daniliuc, Constantin G; Riemann, Burkhard; Schäfers, Michael; Haufe, Günter

    2016-02-15

    Fluorine-containing inhibitors of matrix metalloproteinases (MMPs) can serve as lead structures for the development of (18)F-labeled radioligands. These compounds might be useful as non-invasive imaging probes to characterize pathologies associated with increased MMP activity. Results with a series of fluorinated analogs of a known biphenyl sulfonamide inhibitor have shown that fluorine can be incorporated into two different positions of the molecular scaffold without significant loss of potency in the nanomolar range. Additionally, the potential of a hitherto unknown fluorinated tertiary sulfonamide as MMP inhibitor has been demonstrated.

  5. R-matrix and Potential Model Extrapolations for NACRE Update and Extension Project

    SciTech Connect

    Aikawa, Masayuki; Katsuma, Masahiko; Takahashi, Kohji; Arnould, Marcel; Arai, Koji; Utsunomiya, Hiroaki

    2006-07-12

    NACRE, the 'nuclear astrophysics compilation of reaction rates', has been widely utilized in stellar evolution and nucleosynthesis studies. Its update and extension programme started within a Konan-Universite Libre de Bruxelles (ULB) collaboration. At the present moment, experimental data in refereed journals have been collected, and their theoretical extrapolations are being performed using the R-matrix or potential models. For the 3H(d,n)4He and 2H(p,{gamma})3He reactions, we present preliminary results that could well reproduce the experimental data.

  6. Characteristic element of matrix attachment region mediates vector attachment and enhances nerve growth factor expression in Chinese hamster ovary cells.

    PubMed

    Wang, X Y; Zhang, J H; Sun, Q L; Yao, Z Y; Deng, B G; Guo, W Y; Wang, L; Dong, W H; Wang, F; Zhao, C P; Wang, T Y

    2015-08-07

    Preliminary studies have suggested that a characteristic element of the matrix attachment region (MAR) in human interferon-β mediates the adhesion of vectors to Chinese hamster ovary (CHO) cells. In this study, we investigated if vector adhesion increased nerve growth factor (NGF) expression in CHO cells. The MAR characteristic element sequence of human interferon-β was inserted into the multiple-cloning site of the pEGFP-C1 vector. The target NGF gene was inserted upstream of the MAR characteristic element sequence to construct the MAR/NGF expression vector. The recombinant plasmid was transfected into CHO cells and stable monoclonal cells were selected using G418. NGF mRNA and protein expression was detected by reverse transcriptase-polymerase chain reaction and enzyme-linked immunosorbent assay, respectively. Plasmid reduction experiments were used to determine the state of transfected plasmid in mammalian cells. The insertion of MAR into the vector increased NGF expression levels in CHO cells (1.93- fold) compared to the control. The recombinant plasmid expressing the MAR sequence was digested into a linear space vector. The inserted MAR and NGF sequences were consistent with those inserted into the plasmid before recombination. Therefore, we concluded that the MAR characteristic element mediates vector adhesion to CHO cells and enhances the stability and efficiency of the target gene expression.

  7. Pericellular Matrix Mechanics in the Anulus Fibrosus Predicted by a Three-Dimensional Finite Element Model and In Situ Morphology

    PubMed Central

    Cao, Li; Guilak, Farshid; Setton, Lori A.

    2009-01-01

    Anulus fibrosus (AF) cells have been demonstrated to exhibit dramatic differences in morphology and biologic responses to different types of mechanical stimuli. AF cells may reside as single cell, paired or multiple cells in a contiguous pericellular matrix (PCM), whose structure and properties are expected to have a significant influence on the mechanical stimuli that these cells may experience during physiologic loading of the spine, as well as in tissue degeneration and regeneration. In this study, a computational model was developed to predict the micromechanical stimuli, such as stress and strain, fluid pressure and flow, of cells and their surrounding PCM in the AF tissue using three-dimensional (3D) finite element models based on in situ morphology. 3D solid geometries of cell-PCM regions were registered from serial confocal images obtained from mature rat AF tissues by custom codes. Distinct cell-matrix units were modeled with a custom 3D biphasic finite element code (COMSOL Multiphysics), and simulated to experience uni-axial tensile strain along the local collagen fiber direction. AF cells were predicted to experience higher volumetric strain with a strain amplification ratio (relative to that in the extracellular matrix) of ~ 3.1 – 3.8 at equilibrium, as compared to the PCM domains (1.3 – 1.9). The strain concentrations were generally found at the cell/PCM interface and stress concentration at the PCM/ECM interface. Increased numbers of cells within a contiguous PCM was associated with an apparent increase of strain levels and decreased rate of fluid pressurization in the cell, with magnitudes dependent on the cell size, shape and relative position inside the PCM. These studies provide spatio-temporal information on micromechanics of AF cells in understanding the mechanotransduction in the intervertebral disc. PMID:19946619

  8. Flexible matrix composites: Dynamic characterization, modeling, and potential for driveshaft applications

    NASA Astrophysics Data System (ADS)

    Shan, Ying

    Flexible matrix composites (FMCs) utilize the high elongation capability of elastomers such as polyurethane to withstand large strains in the direction transverse to the fiber reinforcement while retaining strength and stiffness in the longitudinal direction. FMCs are highly anisotropic and can therefore be tailored to achieve distinctive mechanical characteristics that are difficult to obtain using conventional rigid matrix composites. In the current study, the potential of using an FMC to construct a flexurally-soft, torsionally-stiff driveshaft is examined. The FMC selected for the current investigation is a carbon fiber/polyurethane matrix material system. Both quasi-static and dynamic tests have been performed to characterize the properties of the FMC material. By modeling viscoelastic FMC lamina properties with a fractional derivative approach, a novel damping model that accounts for the frequency and temperature dependence of the FMC material is developed. This is the first time fractional derivative model has been applied to a fiber composite. Good agreement between the damping model and experimental data for angle-ply tubes was obtained. Based on the validated damping model, a self-heating model to predict the temperature increase caused by internal damping of a FMC shaft under misaligned rotation is also proposed. A laboratory-scale, misaligned FMC shaft rotation test stand was built to validate the proposed model. Good agreement is shown between the self-heating model predictions and experiment results. This model can be valuable in the selection of constituent materials for FMCs and also in the design of FMC shafts. Preliminary fatigue test results show that FMC materials have potentially good fatigue performance in shaft applications.

  9. Matrix equation decomposition and parallel solution of systems resulting from unstructured finite element problems in electromagnetics

    SciTech Connect

    Cwik, T.; Katz, D.S.

    1996-12-31

    Finite element modeling has proven useful for accurately simulating scattered or radiated electromagnetic fields from complex three-dimensional objects whose geometry varies on the scale of a fraction of an electrical wavelength. An unstructured finite element model of realistic objects leads to a large, sparse, system of equations that needs to be solved efficiently with regard to machine memory and execution time. Both factorization and iterative solvers can be used to produce solutions to these systems of equations. Factorization leads to high memory requirements that limit the electrical problem size of three-dimensional objects that can be modeled. An iterative solver can be used to efficiently solve the system without excessive memory use and in a minimal amount of time if the convergence rate is controlled.

  10. Study on Hankel matrix-based SVD and its application in rolling element bearing fault diagnosis

    NASA Astrophysics Data System (ADS)

    Jiang, Huiming; Chen, Jin; Dong, Guangming; Liu, Tao; Chen, Gang

    2015-02-01

    Based on the traditional theory of singular value decomposition (SVD), singular values (SVs) and ratios of neighboring singular values (NSVRs) are introduced to the feature extraction of vibration signals. The proposed feature extraction method is called SV-NSVR. Combined with selected SV-NSVR features, continuous hidden Markov model (CHMM) is used to realize the automatic classification. Then the SV-NSVR and CHMM based method is applied in fault diagnosis and performance assessment of rolling element bearings. The simulation and experimental results show that this method has a higher accuracy for the bearing fault diagnosis compared with those using other SVD features, and it is effective for the performance assessment of rolling element bearings.

  11. Chiral random matrix model at finite chemical potential: Characteristic determinant and edge universality

    NASA Astrophysics Data System (ADS)

    Liu, Yizhuang; Nowak, Maciej A.; Zahed, Ismail

    2016-08-01

    We derive an exact formula for the stochastic evolution of the characteristic determinant of a class of deformed Wishart matrices following from a chiral random matrix model of QCD at finite chemical potential. In the WKB approximation, the characteristic determinant describes a sharp droplet of eigenvalues that deforms and expands at large stochastic times. Beyond the WKB limit, the edges of the droplet are fuzzy and described by universal edge functions. At the chiral point, the characteristic determinant in the microscopic limit is universal. Remarkably, the physical chiral condensate at finite chemical potential may be extracted from current and quenched lattice Dirac spectra using the universal edge scaling laws, without having to solve the QCD sign problem.

  12. Notch Sensitivity of Woven Ceramic Matrix Composites Under Tensile Loading: An Experimental, Analytical, and Finite Element Study

    NASA Technical Reports Server (NTRS)

    Haque, A.; Ahmed, L.; Ware, T.; Jeelani, S.; Verrilli, Michael J. (Technical Monitor)

    2001-01-01

    The stress concentrations associated with circular notches and subjected to uniform tensile loading in woven ceramic matrix composites (CMCs) have been investigated for high-efficient turbine engine applications. The CMC's were composed of Nicalon silicon carbide woven fabric in SiNC matrix manufactured through polymer impregnation process (PIP). Several combinations of hole diameter/plate width ratios and ply orientations were considered in this study. In the first part, the stress concentrations were calculated measuring strain distributions surrounding the hole using strain gages at different locations of the specimens during the initial portion of the stress-strain curve before any microdamage developed. The stress concentration was also calculated analytically using Lekhnitskii's solution for orthotropic plates. A finite-width correction factor for anisotropic and orthotropic composite plate was considered. The stress distributions surrounding the circular hole of a CMC's plate were further studied using finite element analysis. Both solid and shell elements were considered. The experimental results were compared with both the analytical and finite element solutions. Extensive optical and scanning electron microscopic examinations were carried out for identifying the fracture behavior and failure mechanisms of both the notched and notched specimens. The stress concentration factors (SCF) determined by analytical method overpredicted the experimental results. But the numerical solution underpredicted the experimental SCF. Stress concentration factors are shown to increase with enlarged hole size and the effects of ply orientations on stress concentration factors are observed to be negligible. In all the cases, the crack initiated at the notch edge and propagated along the width towards the edge of the specimens.

  13. Potential hydrodynamic effects on structures by the boundary element method

    NASA Astrophysics Data System (ADS)

    Ouazar, D.; Benmansour, N.

    Problems based on a potential or streamfunction formulation of the BEM for the studying of hydrodynamic forces are addressed, with particular attention given to fluid applications of the constant conventional BEM (CBEM) and the regular BEM (RBEM). Comparison of the two methods for three numerical examples (the flow past a circular obstacle in an infinite medium, the flow past a circular obstacle in a channel, and the flow past a symmetric NACA 0018 airfoil) demonstrates the superiority of the RBEM over the CBEM in both accuracy and computational cost. It is noted that the optimal location of the singular points outside the domain remains unsolved on a rational basis.

  14. Optical elements formed by compressed gases: Analysis and potential applications

    NASA Technical Reports Server (NTRS)

    Howes, W. L.

    1986-01-01

    Spherical, cylindrical, and conical shock waves are optically analogous to gas lenses. The geometrical optics of these shock configurations are analyzed as they pertain to flow visualization instruments, particularly the rainbow schlieren apparatus and single-pass interferometers. It is proposed that a lens or mirror formed by gas compressed between plastic sheets has potential as a fluid visualization test object; as the objective mirror in a very large space-based telescope, communication antenna, or energy collector; as the objective mirror in inexpensive commercial telescopes; and as a component in fluid visualization apparatuses.

  15. Singular-potential random-matrix model arising in mean-field glassy systems

    NASA Astrophysics Data System (ADS)

    Akemann, Gernot; Villamaina, Dario; Vivo, Pierpaolo

    2014-06-01

    We consider an invariant random matrix ensemble where the standard Gaussian potential is distorted by an additional single pole of arbitrary fixed order. Potentials with first- and second-order poles have been considered previously and found applications in quantum chaos and number theory. Here we present an application to mean-field glassy systems. We derive and solve the loop equation in the planar limit for the corresponding class of potentials. We find that the resulting mean or macroscopic spectral density is generally supported on two disconnected intervals lying on the two sides of the repulsive pole, whose edge points can be completely determined imposing the additional constraint of traceless matrices on average. For an unbounded potential with an attractive pole, we also find a possible one-cut solution for certain values of the couplings, which is ruled out when the traceless condition is imposed. Motivated by the calculation of the distribution of the spin-glass susceptibility in the Sherrington-Kirkpatrick spin-glass model, we consider in detail a second-order pole for a zero-trace model and provide the most explicit solution in this case. In the limit of a vanishing pole, we recover the standard semicircle. Working in the planar limit, our results apply to matrices with orthogonal, unitary, and symplectic invariance. Numerical simulations and an independent analytical Coulomb fluid calculation for symmetric potentials provide an excellent confirmation of our results.

  16. Singular-potential random-matrix model arising in mean-field glassy systems.

    PubMed

    Akemann, Gernot; Villamaina, Dario; Vivo, Pierpaolo

    2014-06-01

    We consider an invariant random matrix ensemble where the standard Gaussian potential is distorted by an additional single pole of arbitrary fixed order. Potentials with first- and second-order poles have been considered previously and found applications in quantum chaos and number theory. Here we present an application to mean-field glassy systems. We derive and solve the loop equation in the planar limit for the corresponding class of potentials. We find that the resulting mean or macroscopic spectral density is generally supported on two disconnected intervals lying on the two sides of the repulsive pole, whose edge points can be completely determined imposing the additional constraint of traceless matrices on average. For an unbounded potential with an attractive pole, we also find a possible one-cut solution for certain values of the couplings, which is ruled out when the traceless condition is imposed. Motivated by the calculation of the distribution of the spin-glass susceptibility in the Sherrington-Kirkpatrick spin-glass model, we consider in detail a second-order pole for a zero-trace model and provide the most explicit solution in this case. In the limit of a vanishing pole, we recover the standard semicircle. Working in the planar limit, our results apply to matrices with orthogonal, unitary, and symplectic invariance. Numerical simulations and an independent analytical Coulomb fluid calculation for symmetric potentials provide an excellent confirmation of our results.

  17. First order nonadiabatic coupling matrix elements between excited states: Implementation and application at the TD-DFT and pp-TDA levels

    NASA Astrophysics Data System (ADS)

    Li, Zhendong; Suo, Bingbing; Liu, Wenjian

    2014-12-01

    The recently proposed rigorous yet abstract theory of first order nonadiabatic coupling matrix elements (fo-NACME) between electronically excited states [Z. Li and W. Liu, J. Chem. Phys. 141, 014110 (2014)] is specified in detail for two widely used models: The time-dependent density functional theory and the particle-particle Tamm-Dancoff approximation. The actual implementation employs a Lagrangian formalism with atomic-orbital based direct algorithms, which makes the computation of fo-NACME very similar to that of excited-state gradients. Although the methods have great potential in investigating internal conversions and nonadiabatic dynamics between excited states of large molecules, only prototypical systems as a first pilot application are considered here to illustrate some conceptual aspects.

  18. First order nonadiabatic coupling matrix elements between excited states: Implementation and application at the TD-DFT and pp-TDA levels

    SciTech Connect

    Li, Zhendong; Suo, Bingbing; Liu, Wenjian

    2014-12-28

    The recently proposed rigorous yet abstract theory of first order nonadiabatic coupling matrix elements (fo-NACME) between electronically excited states [Z. Li and W. Liu, J. Chem. Phys. 141, 014110 (2014)] is specified in detail for two widely used models: The time-dependent density functional theory and the particle-particle Tamm-Dancoff approximation. The actual implementation employs a Lagrangian formalism with atomic-orbital based direct algorithms, which makes the computation of fo-NACME very similar to that of excited-state gradients. Although the methods have great potential in investigating internal conversions and nonadiabatic dynamics between excited states of large molecules, only prototypical systems as a first pilot application are considered here to illustrate some conceptual aspects.

  19. Bacteria inside semiconductors as potential sensor elements: biochip progress.

    PubMed

    Sah, Vasu R; Baier, Robert E

    2014-01-01

    It was discovered at the beginning of this Century that living bacteria-and specifically the extremophile Pseudomonas syzgii-could be captured inside growing crystals of pure water-corroding semiconductors-specifically germanium-and thereby initiated pursuit of truly functional "biochip-based" biosensors. This observation was first made at the inside ultraviolet-illuminated walls of ultrapure water-flowing semiconductor fabrication facilities (fabs) and has since been, not as perfectly, replicated in simpler flow cell systems for chip manufacture, described here. Recognizing the potential importance of these adducts as optical switches, for example, or probes of metabolic events, the influences of the fabs and their components on the crystal nucleation and growth phenomena now identified are reviewed and discussed with regard to further research needs. For example, optical beams of current photonic circuits can be more easily modulated by integral embedded cells into electrical signals on semiconductors. Such research responds to a recently published Grand Challenge in ceramic science, designing and synthesizing oxide electronics, surfaces, interfaces and nanoscale structures that can be tuned by biological stimuli, to reveal phenomena not otherwise possible with conventional semiconductor electronics. This short review addresses only the fabrication facilities' features at the time of first production of these potential biochips.

  20. Bacteria inside semiconductors as potential sensor elements: biochip progress.

    PubMed

    Sah, Vasu R; Baier, Robert E

    2014-01-01

    It was discovered at the beginning of this Century that living bacteria-and specifically the extremophile Pseudomonas syzgii-could be captured inside growing crystals of pure water-corroding semiconductors-specifically germanium-and thereby initiated pursuit of truly functional "biochip-based" biosensors. This observation was first made at the inside ultraviolet-illuminated walls of ultrapure water-flowing semiconductor fabrication facilities (fabs) and has since been, not as perfectly, replicated in simpler flow cell systems for chip manufacture, described here. Recognizing the potential importance of these adducts as optical switches, for example, or probes of metabolic events, the influences of the fabs and their components on the crystal nucleation and growth phenomena now identified are reviewed and discussed with regard to further research needs. For example, optical beams of current photonic circuits can be more easily modulated by integral embedded cells into electrical signals on semiconductors. Such research responds to a recently published Grand Challenge in ceramic science, designing and synthesizing oxide electronics, surfaces, interfaces and nanoscale structures that can be tuned by biological stimuli, to reveal phenomena not otherwise possible with conventional semiconductor electronics. This short review addresses only the fabrication facilities' features at the time of first production of these potential biochips. PMID:24961215

  1. Bacteria Inside Semiconductors as Potential Sensor Elements: Biochip Progress

    PubMed Central

    Sah, Vasu R.; Baier, Robert E.

    2014-01-01

    It was discovered at the beginning of this Century that living bacteria—and specifically the extremophile Pseudomonas syzgii—could be captured inside growing crystals of pure water-corroding semiconductors—specifically germanium—and thereby initiated pursuit of truly functional “biochip-based” biosensors. This observation was first made at the inside ultraviolet-illuminated walls of ultrapure water-flowing semiconductor fabrication facilities (fabs) and has since been, not as perfectly, replicated in simpler flow cell systems for chip manufacture, described here. Recognizing the potential importance of these adducts as optical switches, for example, or probes of metabolic events, the influences of the fabs and their components on the crystal nucleation and growth phenomena now identified are reviewed and discussed with regard to further research needs. For example, optical beams of current photonic circuits can be more easily modulated by integral embedded cells into electrical signals on semiconductors. Such research responds to a recently published Grand Challenge in ceramic science, designing and synthesizing oxide electronics, surfaces, interfaces and nanoscale structures that can be tuned by biological stimuli, to reveal phenomena not otherwise possible with conventional semiconductor electronics. This short review addresses only the fabrication facilities' features at the time of first production of these potential biochips. PMID:24961215

  2. Three dimensional magnetostatic finite element for gaps and iron shells using magnetic scalar potentials

    SciTech Connect

    Guerin, C.; Tanneau, G.; Meunier, G.; Brunotte, X.; Albertini, J.B.

    1994-09-01

    This paper deals with magnetostatic finite element formulations for modeling narrow gaps in an iron core, as well as thin iron shells. These special elements have been developed for gaps in transformers or motors. Nodal elements are used with magnetic scalar potentials as state variable. The principle and the formulations of the new finite elements are described. Three numerical examples are then presented so as to validate and verify the usefulness of the special elements in terms of reduction of number of unknowns and CPU time.

  3. Elemental biochemical analysis of the polysaccharides in the extracellular matrix of the yeast Saccharomyces cerevisiae.

    PubMed

    Faria-Oliveira, Fábio; Carvalho, Joana; Belmiro, Celso L R; Ramalho, Gustavo; Pavão, Mauro; Lucas, Cândida; Ferreira, Célia

    2015-06-01

    In yeast multicellular aggregates, such as biofilms and colonies, cells are supported by a yeast extracellular matrix (yECM) of glycosidic nature, the composition of which is mostly unknown. Saccharomyces cerevisiae ECM was produced, extracted and partitioned. An analytical-grade pure glycoside fraction was obtained, fractionated by anionic exchange liquid chromatography and analyzed by gas chromatography-mass spectrometry and polyacrylamide gel electrophoresis. Two different molecular weight polysaccharides were found, composed of glucose, mannose and small relative amounts of galactose. One of the polysaccharides had a low molecular weight, compatible with the association with glycoproteins abundantly occurring in yECM. In addition, these polysaccharide species were separated by diaminopropane agarose gel electrophoresis and induced metachromatic shift, suggesting chemical substitution, which was corroborated by anticoagulation activity. This was shown to be associated with the double deletion of the yeast homologues of the mammalian Hedgehog modulators Hhatl and Hhat, respectively yeast Gup1 and Gup2. These results pioneer the study of the molecular biology of the ECM supporting S. cerevisiae multicellular aggregates such as biofilms.

  4. Discrete Element Framework for Modelling Extracellular Matrix, Deformable Cells and Subcellular Components

    PubMed Central

    Gardiner, Bruce S.; Wong, Kelvin K. L.; Joldes, Grand R.; Rich, Addison J.; Tan, Chin Wee; Burgess, Antony W.; Smith, David W.

    2015-01-01

    This paper presents a framework for modelling biological tissues based on discrete particles. Cell components (e.g. cell membranes, cell cytoskeleton, cell nucleus) and extracellular matrix (e.g. collagen) are represented using collections of particles. Simple particle to particle interaction laws are used to simulate and control complex physical interaction types (e.g. cell-cell adhesion via cadherins, integrin basement membrane attachment, cytoskeletal mechanical properties). Particles may be given the capacity to change their properties and behaviours in response to changes in the cellular microenvironment (e.g., in response to cell-cell signalling or mechanical loadings). Each particle is in effect an ‘agent’, meaning that the agent can sense local environmental information and respond according to pre-determined or stochastic events. The behaviour of the proposed framework is exemplified through several biological problems of ongoing interest. These examples illustrate how the modelling framework allows enormous flexibility for representing the mechanical behaviour of different tissues, and we argue this is a more intuitive approach than perhaps offered by traditional continuum methods. Because of this flexibility, we believe the discrete modelling framework provides an avenue for biologists and bioengineers to explore the behaviour of tissue systems in a computational laboratory. PMID:26452000

  5. Extracellular matrix family proteins that are potential targets of Dd-STATa in Dictyostelium discoideum.

    PubMed

    Shimada, Nao; Nishio, Keiko; Maeda, Mineko; Urushihara, Hideko; Kawata, Takefumi

    2004-10-01

    Dd-STATa is a functional Dictyostelium homologue of metazoan STAT (signal transducers and activators of transcription) proteins, which is activated by cAMP and is thereby translocated into the nuclei of anterior tip cells of the prestalk region of the slug. By using in situ hybridization analyses, we found that the SLF308 cDNA clone, which contains the ecmF gene that encodes a putative extracellular matrix protein and is expressed in the anterior tip cells, was greatly down-regulated in the Dd-STATa-null mutant. Disruption of the ecmF gene, however, resulted in almost no phenotypic change. The absence of any obvious mutant phenotype in the ecmF-null mutant could be due to a redundancy of similar genes. In fact, a search of the Dictyostelium whole genome database demonstrates the existence of an additional 16 homologues, all of which contain a cellulose-binding module. Among these homologues, four genes show Dd-STATa-dependent expression, while the others are Dd-STATa-independent. We discuss the potential role of Dd-STATa in morphogenesis via its effect on the interaction between cellulose and these extracellular matrix family proteins.

  6. An Arnoldi-Based Iterative Scheme for Nonsymmetric Matrix Pencils Arising in Finite Element Stability Problems

    NASA Astrophysics Data System (ADS)

    Natarajan, Ramesh

    1992-05-01

    A method for computing the desired eigenvalues and corresponding eigenvectors of a large-scale, nonsymmetric, complex generalized eigenvalue problem is described. This scheme is primarily intended for the normal mode analysis and the stability characterization of the stationary states of parameterized time-dependent partial differential equations, in particular, when a finite element method is used for the numerical discretization. The algorithm, which is based on the previous work of Saad, may be succintly described as a multiple shift-and-invert, restarted Arnoldi procedure which uses reorthogonalization and automatic shift selection to provide stability and convergence, while minimizing the overall computational effort. The application and efficiency of the method is illustrated using two representative test problems.

  7. Measurement of the electroweak top quark production cross section and the CKM matrix element Vtb with the D0 experiment

    SciTech Connect

    Kirsch, Matthias

    2009-06-29

    At particle accelerators the Standard Model has been tested and will be tested further to a great precision. The data analyzed in this thesis have been collected at the world's highest energetic-collider, the Tevatron, located at the Fermi National Accelerator Laboratory (FNAL) in the vicinity of Chicago, IL, USA. There, protons and antiprotons are collided at a center-of-mass energy of {radical}s = 1.96 TeV. The discovery of the top quark was one of the remarkable results not only for the CDF and D0 experiments at the Tevatron collider, but also for the Standard Model, which had predicted the existence of the top quark because of symmetry arguments long before already. Still, the Tevatron is the only facility able to produce top quarks. The predominant production mechanism of top quarks is the production of a top-antitop quark pair via the strong force. However, the Standard Model also allows the production of single top quarks via the electroweak interaction. This process features the unique opportunity to measure the |Vtb| matrix element of the Cabbibo-Kobayashi-Maskawa (CKM) matrix directly, without assuming unitarity of the matrix or assuming that the number of quark generations is three. Hence, the measurement of the cross section of electroweak top quark production is more than the technical challenge to extract a physics process that only occurs one out of ten billion collisions. It is also an important test of the V-A structure of the electroweak interaction and a potential window to physics beyond the Standard Model in the case where the measurement of |V{sub tb}| would result in a value significantly different from 1, the value predicted by the Standard Model. At the Tevatron two production processes contribute significantly to the production of single top quarks: the production via the t-channel, also called W-gluon fusion, and the production via the s-channel, known as well as W* process. This analysis searches for the combined s+t channel

  8. The nuclear matrix elements of 0vββ decay and the NUMEN project at INFN-LNS

    NASA Astrophysics Data System (ADS)

    Cappuzzello, F.; Agodi, C.; Aciksoz, E.; Acosta, L.; Aslanouglou, X.; Auerbach, N.; Bijker, R.; Bonanno, D.; Bongiovanni, D.; Borello, T.; Boudhaim, S.; Bouhssa, M. L.; Boztosun, I.; Calabretta, L.; Calanna, A.; Carbone, D.; Cavallaro, M.; Calvo, D.; Chávez Lomelí, E. R.; Colonna, M.; D'Agostino, G.; Deshmukh, N.; de Faria, P. N.; Ferrero, A.; Foti, A.; Finocchiaro, P.; Gomes, P. R. S.; Greco, V.; Hacisalihoglu, A.; Housni, Z.; Khouaja, A.; Inchaou, J.; Lanzalone, G.; La Via, F.; Lay, J. A.; Lenske, H.; Linares, R.; Lubian, J.; Iazzi, F.; Introzzi, R.; Lavagno, A.; Lo Presti, D.; Medina, N.; Mendes, D. R.; Muoio, A.; Oliveira, J. R. B.; Pakou, A.; Pandola, L.; Rifuggiato, D.; Rodrigues, M. R. D.; Santagati, G.; Santopinto, E.; Scaltrito, L.; Sgouros, O.; Solakcı, S. O.; Soukeras, V.; Tudisco, S.; Vsevolodovna, R. I. M.; Zagatto, V.

    2016-07-01

    An innovative technique to access the nuclear matrix elements entering the expression of the life time of the double beta decay by relevant cross section measurements of double charge exchange reactions is proposed. A key aspect of the project is the use of the MAGNEX large acceptance magnetic spectrometer, for the detection of the ejectiles, and of the LNS K800 Superconducting Cyclotron (CS), for the acceleration of the required high resolution and low emittance heavy-ion beams, already in operation at INFN Laboratory Nazionali del Sud in Catania (Italy). However, a major upgrade is foreseen for the INFN-LNS research infrastructure to cope with beam currents as high as several ppA required by the project.

  9. Differential cross sections and spin density matrix elements for the reaction {gamma}p{yields}p{omega}

    SciTech Connect

    Williams, M.; Applegate, D.; Bellis, M.; Meyer, C. A.; Dey, B.; Dickson, R.; Krahn, Z.; McCracken, M. E.; Moriya, K.; Schumacher, R. A.; Adhikari, K. P.; Careccia, S. L.; Dodge, G. E.; Klein, A.; Mayer, M.; Nepali, C. S.; Niroula, M. R.; Seraydaryan, H.; Tkachenko, S.; Weinstein, L. B.

    2009-12-15

    High-statistics differential cross sections and spin-density matrix elements for the reaction {gamma}p{yields}p{omega} have been measured using the CEBAF large acceptance spectrometer (CLAS) at Jefferson Lab for center-of-mass (c.m.) energies from threshold up to 2.84 GeV. Results are reported in 112 10-MeV wide c.m. energy bins, each subdivided into cos{theta}{sub c.m.}{sup {omega}} bins of width 0.1. These are the most precise and extensive {omega} photoproduction measurements to date. A number of prominent structures are clearly present in the data. Many of these have not previously been observed due to limited statistics in earlier measurements.

  10. Occupancies of individual orbits, and the nuclear matrix element of the {sup 76}Ge neutrinoless {beta}{beta} decay

    SciTech Connect

    Menendez, J.; Poves, A.

    2009-10-15

    We discuss the variation of the nuclear matrix element (NME) for the neutrinoless double beta (0{nu}{beta}{beta}) decay of {sup 76}Ge when the wave functions are constrained to reproduce the experimental occupancies of the two nuclei involved in the transition. In the interacting shell model description the value of the NME is enhanced about 15% compared to previous calculations, whereas in the QRPA the NME's are reduced by 20%-30%. This diminishes the discrepancies between both approaches. In addition, we discuss the effect of the short-range correlations on the NME in light of the recently proposed parametrizations based on a consistent renormalization of the 0{nu}{beta}{beta} transition operator.

  11. The (d,2He) reaction on Se76 and the double-β-decay matrix elements for A=76

    NASA Astrophysics Data System (ADS)

    Grewe, E.-W.; Bäumer, C.; Dohmann, H.; Frekers, D.; Harakeh, M. N.; Hollstein, S.; Johansson, H.; Popescu, L.; Rakers, S.; Savran, D.; Simon, H.; Thies, J. H.; van den Berg, A. M.; Wörtche, H. J.; Zilges, A.

    2008-10-01

    The (d,2He) charge-exchange reaction on Se76 was studied at an incident energy of 183 MeV. The outgoing two protons in the 1S0 state, referred to as He2, were both momentum analyzed and detected by the same spectrometer and detector. The experiment was performed at KVI, Groningen, using the magnetic spectrometer BBS at three angular positions: 0°,2.5°, and 5°. Excitation-energy spectra of the residual nucleus As76 were obtained with an energy resolution of about 120 keV (FWHM). Gamow-Teller (GT+) transition strengths were extracted up to 5 MeV and compared with those from an (n,p) experiment at low resolution. Together with the GT- transition strengths from the 76Ge(p,n) experiment leading to the same intermediate nucleus, the nuclear matrix element of the two-neutrino double-β decay of Ge76 was evaluated.

  12. Verification of Threshold Voltage Variation of Scaled Transistors with Ultralarge-Scale Device Matrix Array Test Element Group

    NASA Astrophysics Data System (ADS)

    Tsunomura, Takaaki; Nishida, Akio; Hiramoto, Toshiro

    2009-12-01

    Randomness of threshold voltage (VT) variations of negative channel field effect transistors (NFETs) and positive channel field effect transistors (PFETs) in the 65 nm technology is precisely examined. For this purpose, an ultralarge-scale device matrix array test element group (DMA-TEG) that contains 1 million single-size metal-oxide-semiconductor field-effect transistors (MOSFETs) has been designed and fabricated, and a very rapid measurement system has been developed. By evaluating VT of a very large number of MOSFETs, VT variation can be precisely evaluated. This rapid measurement is achieved by parallel address signal input, optimization of the measurement program, and 4-chip parallel measurements. The measured VT variations are decomposed into random and systematic components. The results reveal that the random component is overwhelmingly dominant in the VT variations in the 65 nm technology and that the VT variations exhibit a normal distribution up to ±5σ.

  13. Am phases in the matrix of a U–Pu–Zr alloy with Np, Am, and rare-earth elements

    SciTech Connect

    Janney, Dawn E.; Kennedy, J. Rory; Madden, James W.; O’Holleran, Thomas P.

    2015-01-01

    Phases and microstructures in the matrix of an as-cast U-Pu-Zr alloy with 3 wt% Am, 2% Np, and 8% rare-earth elements were characterized by scanning and transmission electron microscopy. The matrix consists primarily of two phases, both of which contain Am: ζ-(U, Np, Pu, Am) (~70 at% U, 5% Np, 14% Pu, 1% Am, and 10% Zr) and δ-(U, Np, Pu, Am)Zr2 (~25% U, 2% Np, 10-15% Pu, 1-2% Am, and 55-60 at% Zr). These phases are similar to those in U-Pu-Zr alloys, although the Zr content in ζ-(U, Np, Pu, Am) is higher than that in ζ-(U, Pu) and the Zr content in δ-(U, Np, Pu, Am)Zr2 is lower than that in δ-UZr2. Nanocrystalline actinide oxides with structures similar to UO2 occurred in some areas, but may have formed by reactions with the atmosphere during sample handling. Planar features consisting of a central zone of ζ-(U, Np, Pu, Am) bracketed by zones of δ-(U, Np, Pu, Am)Zr2 bound irregular polygons ranging in size from a few micrometers to a few tens of micrometers across. The rest of the matrix consists of elongated domains of ζ-(U, Np, Pu, Am) and δ-(U, Np, Pu, Am)Zr2. Each of these domains is a few tens of nanometers across and a few hundred nanometers long. The domains display strong preferred orientations involving areas a few hundred nanometers to a few micrometers across.

  14. Dirac electrons in the presence of a matrix potential barrier: application to graphene and topological insulators.

    PubMed

    Erementchouk, Mikhail; Mazumder, Pinaki; Khan, M A; Leuenberger, Michael N

    2016-03-23

    Scattering of 2D Dirac electrons on a rectangular matrix potential barrier is considered using the formalism of spinor transfer matrices. It is shown, in particular, that in the absence of the mass term, the Klein tunneling is not necessarily suppressed but occurs at oblique incidence. The formalism is applied to studying waveguiding modes of the barrier, which are supported by the edge and bulk states. The condition of the existence of the uni-directionality property is found. We show that the band of edge states is always finite with massless excitations, while the spectrum of the bulk states, depending on the parameters of the barrier, may consist of the infinite or finite band with both, massive and massless, low-energy excitations. The effect of the Zeeman term is considered and the condition of the appearance of two distinct energy-dependent directions corresponding to the Klein tunneling is found. PMID:26902304

  15. Dirac electrons in the presence of a matrix potential barrier: application to graphene and topological insulators

    NASA Astrophysics Data System (ADS)

    Erementchouk, Mikhail; Mazumder, Pinaki; Khan, M. A.; Leuenberger, Michael N.

    2016-03-01

    Scattering of 2D Dirac electrons on a rectangular matrix potential barrier is considered using the formalism of spinor transfer matrices. It is shown, in particular, that in the absence of the mass term, the Klein tunneling is not necessarily suppressed but occurs at oblique incidence. The formalism is applied to studying waveguiding modes of the barrier, which are supported by the edge and bulk states. The condition of the existence of the uni-directionality property is found. We show that the band of edge states is always finite with massless excitations, while the spectrum of the bulk states, depending on the parameters of the barrier, may consist of the infinite or finite band with both, massive and massless, low-energy excitations. The effect of the Zeeman term is considered and the condition of the appearance of two distinct energy-dependent directions corresponding to the Klein tunneling is found.

  16. Determination of trace elements in dolomite and gypsum by atomic absorption spectrometry: overcoming the matrix interference by flotation separation

    NASA Astrophysics Data System (ADS)

    Stafilov, Trajče; Zendelovska, Dragica; Pavlovska, Gorica; Čundeva, Katarina

    2002-05-01

    The interferences of Ca and Mg as matrix elements in dolomite and gypsum on Ag, Cd, Cr, Mn, Tl and Zn absorbances during their electrothermal atomic absorption spectrometric (ETAAS) determination are investigated. The results reveal that Ca and Mg do not interfere on Zn and Mn, tend to decrease absorbances of Ag, Cd and Cr, while Tl suffers the most significant influence. A flotation separation method is proposed to eliminate matrix interferences. Hydrated iron(III) oxide, Fe 2O 3· xH 2O, and iron(III) hexamethylenedithiocarbamate, Fe(HMDTC) 3, are applied as flotation collectors. The influence of hydrophobic dithiocarbamate anion, HMDTC, on flotation recoveries of each analyte is studied. The most suitable concentrations of dolomite and gypsum solutions for flotation are determined. To avoid flotation suppression due to the reaction of Ca 2+ and Mg 2+ with surfactant ions, a fit foaming agent was selected. The elements present in dolomite and gypsum as traces have been analyzed by ETAAS. Their ETAAS limits of detection following flotation are found to be 0.021 μg·g -1 for Ag, 0.019 μg·g -1 for Cd, 0.014 μg·g -1 for Cr and 0.11 μg·g -1 for Tl. The determination of Mn and Zn can be performed by flame AAS (FAAS). The limit of detection for Mn is 1.5 μg·g -1, while for Zn 0.8 μg·g -1.

  17. Multi-scale damage modelling in a ceramic matrix composite using a finite-element microstructure meshfree methodology.

    PubMed

    Saucedo-Mora, L; Marrow, T J

    2016-07-13

    The problem of multi-scale modelling of damage development in a SiC ceramic fibre-reinforced SiC matrix ceramic composite tube is addressed, with the objective of demonstrating the ability of the finite-element microstructure meshfree (FEMME) model to introduce important aspects of the microstructure into a larger scale model of the component. These are particularly the location, orientation and geometry of significant porosity and the load-carrying capability and quasi-brittle failure behaviour of the fibre tows. The FEMME model uses finite-element and cellular automata layers, connected by a meshfree layer, to efficiently couple the damage in the microstructure with the strain field at the component level. Comparison is made with experimental observations of damage development in an axially loaded composite tube, studied by X-ray computed tomography and digital volume correlation. Recommendations are made for further development of the model to achieve greater fidelity to the microstructure. This article is part of the themed issue 'Multiscale modelling of the structural integrity of composite materials'.

  18. Multi-scale damage modelling in a ceramic matrix composite using a finite-element microstructure meshfree methodology.

    PubMed

    Saucedo-Mora, L; Marrow, T J

    2016-07-13

    The problem of multi-scale modelling of damage development in a SiC ceramic fibre-reinforced SiC matrix ceramic composite tube is addressed, with the objective of demonstrating the ability of the finite-element microstructure meshfree (FEMME) model to introduce important aspects of the microstructure into a larger scale model of the component. These are particularly the location, orientation and geometry of significant porosity and the load-carrying capability and quasi-brittle failure behaviour of the fibre tows. The FEMME model uses finite-element and cellular automata layers, connected by a meshfree layer, to efficiently couple the damage in the microstructure with the strain field at the component level. Comparison is made with experimental observations of damage development in an axially loaded composite tube, studied by X-ray computed tomography and digital volume correlation. Recommendations are made for further development of the model to achieve greater fidelity to the microstructure. This article is part of the themed issue 'Multiscale modelling of the structural integrity of composite materials'. PMID:27242308

  19. [Potential and usefulness of the analysis of metallic elements in blood platelets].

    PubMed

    Catalani, S; Marini, M; Consolandi, O; Gilberti, M E; Apostoli, P

    2008-01-01

    Platelets represent an important fraction of blood, whose composition and interactions in many physiological and pathological processes were a subject of several studies. Determination of trace elements in this component was investigated in past studies (70-80's) on small samples and by analytical techniques giving rise to not always reliable results. This study was aimed at the development of a simple method for platelet isolation and determination of trace elements by inductively coupled plasma-mass spectrometry (ICP-MS). The method was applied on blood samples from 35 healthy males with mean age of 42.5 years. The obtained results gave us the opportunity to establish a reference range of trace elements in this matrix that can be used for the interpretation of results in occupationally/environmentally exposed people or hill subjects.

  20. Structural Anomalies Detected in Ceramic Matrix Composites Using Combined Nondestructive Evaluation and Finite Element Analysis (NDE and FEA)

    NASA Technical Reports Server (NTRS)

    Abdul-Aziz, Ali; Baaklini, George Y.; Bhatt, Ramakrishna T.

    2003-01-01

    Most reverse engineering approaches involve imaging or digitizing an object and then creating a computerized reconstruction that can be integrated, in three dimensions, into a particular design environment. The rapid prototyping technique builds high-quality physical prototypes directly from computer-aided design files. This fundamental technique for interpreting and interacting with large data sets is being used here via Velocity2 (an integrated image-processing software, ref. 1) using computed tomography (CT) data to produce a prototype three-dimensional test specimen model for analyses. A study at the NASA Glenn Research Center proposes to use these capabilities to conduct a combined nondestructive evaluation (NDE) and finite element analysis (FEA) to screen pretest and posttest structural anomalies in structural components. A tensile specimen made of silicon nitrite (Si3N4) ceramic matrix composite was considered to evaluate structural durability and deformity. Ceramic matrix composites are being sought as candidate materials to replace nickel-base superalloys for turbine engine applications. They have the unique characteristics of being able to withstand higher operating temperatures and harsh combustion environments. In addition, their low densities relative to metals help reduce component mass (ref. 2). Detailed three-dimensional volume rendering of the tensile test specimen was successfully carried out with Velocity2 (ref. 1) using two-dimensional images that were generated via computed tomography. Subsequent, three-dimensional finite element analyses were performed, and the results obtained were compared with those predicted by NDE-based calculations and experimental tests. It was shown that Velocity2 software can be used to render a three-dimensional object from a series of CT scan images with a minimum level of complexity. The analytical results (ref. 3) show that the high-stress regions correlated well with the damage sites identified by the CT scans

  1. Transforming potential and matrix stiffness co-regulate confinement sensitivity of tumor cell migration

    PubMed Central

    Pathak, Amit

    2013-01-01

    It is now well established that tumor cell invasion through tissue is strongly regulated by the microstructural and mechanical properties of the extracellular matrix (ECM). However, it remains unclear how these physical microenvironmental inputs are jointly processed with oncogenic lesions to drive invasion. In this study, we address this open question by combining a microfabricated polyacrylamide channel (μPAC) platform that enables independent control of ECM stiffness and confinement with an isogenically-matched breast tumor progression series in which the oncogenes ErbB2 and 14-3-3ζ are overexpressed independently or in tandem. We find that increasing channel confinement and overexpressing ErbB2 both promote cell migration to a similar degree when other parameters are kept constant. In contrast, 14-3-3ζ overexpression slows migration speed, and does so in a fashion that dwarfs effects of ECM confinement and stiffness. We also find that ECM stiffness dramatically enhances cell motility when combined with ErbB2 overexpression, demonstrating that biophysical cues and cell-intrinsic parameters promote cell invasion in an integrative manner. Morphometric analysis of cells inside the μPAC platform reveals that the rapid cell migration induced by narrow channels and ErbB2 overexpression both are accompanied by increased cell polarization. Disruption of this polarization by pharmacological inhibition of Rac GTPase phenocopies 14-3-3ζ overexpression by reducing cell polarization and slowing migration. By systematically measuring migration speed as a function of matrix stiffness and confinement, we also quantify for the first time the sensitivity of migration speed to microchannel properties and transforming potential. These results demonstrate that oncogenic lesions and ECM biophysical properties can synergistically interact to drive invasive migration, and that both inputs may act through common molecular mechanisms to enhance migration speed. PMID:23832051

  2. Expression of matrix metalloproteinase-9 in oral potentially malignant disorders: A systematic review

    PubMed Central

    Venugopal, Archana; Uma Maheswari, TN

    2016-01-01

    Matrix metalloproteinase-9 (MMP-9) is an inducible enzyme. Oral potentially malignant disorders (OPMDs) are considered as the early tissue changes that happen due to various habits such as smoking tobacco, chewing tobacco or stress. This alteration in the tissues alters the expression of MMP-9. The rationale of the review is to know the expression of MMP-9 in OPMDs. Hand searching and electronic databases such as PubMed and ScienceDirect were done for mesh terms such as OPMDs and MMP-9. Eight articles were obtained, after applying inclusion and exclusion criteria. These articles were assessed with QUADAS and data were extracted and evaluated. The included eight studies were done in 182 oral squamous cell carcinoma cases, 430 OPMDs (146 oral lichen planus, 264 leukoplakia and 20 oral submucous fibrosis) and 352 healthy controls evaluated for MMP-9. MMP-9 expression was found to be elevated in tissue, serum and saliva samples of OPMDs than in healthy controls. There is only one study in each serum and saliva samples to evaluate MMP-9. Saliva being noninvasive and serum being minimally invasive, more studies need to be done in both serum and saliva to establish MMP-9 as an early diagnostic marker in OPMDs to know its potential in malignant transformation. PMID:27721614

  3. Evaluation of the Technical-Economic Potential of Particle- Reinforced Aluminum Matrix Composites and Electrochemical Machining

    NASA Astrophysics Data System (ADS)

    Schubert, A.; Götze, U.; Hackert-Oschätzchen, M.; Lehnert, N.; Herold, F.; Meichsner, G.; Schmidt, A.

    2016-03-01

    Compared to conventional cutting, the processing of materials by electrochemical machining offers some technical advantages like high surface quality, no thermal or mechanical impact on the work piece and preservation of the microstructure of the work piece material. From the economic point of view, the possibility of process parallelization and the absence of any process-related tool wear are mentionable advantages of electrochemical machining. In this study, based on experimental results, it will be evaluated to what extent the electrochemical machining is technically and economically suitable for the finish-machining of particle- reinforced aluminum matrix composites (AMCs). Initial studies showed that electrochemical machining - in contrast to other machining processes - has the potential to fulfil demanding requirements regarding precision and surface quality of products or components especially when applied to AMCs. In addition, the investigations show that processing of AMCs by electrochemical machining requires less energy than the electrochemical machining of stainless steel. Therefore, an evaluation of electrochemically machined AMCs - compared to stainless steel - from a technical and an economic perspective will be presented in this paper. The results show the potential of electro-chemically machined AMCs and contribute to the enhancement of instruments for technical-economic evaluations as well as a comprehensive innovation control.

  4. Transient and stability analysis of large scale rotor-bearing system with strong nonlinear elements by the mode summation-transfer matrix method

    NASA Astrophysics Data System (ADS)

    Gu, Zhiping

    This paper extends Riccati transfer matrix method to the transient and stability analysis of large scale rotor-bearing systems with strong nonlinear elements, and proposes a mode summation-transfer matrix method, in which the field transfer matrix of a distributed mass uniform shaft segment is obtained with the aid of the idea of mode summation and Newmark beta formulation, and the Riccati transfer matrix method is adopted to stablize the boundary value problem of the nonlinear systems. In this investigation, the real nonlinearity of the strong nonlinear elements is considered, not linearized, and the advantages of the Riccati transfer matrix are retained. So, this method is especially applicable to analyze the transient response and stability of large-scale rotor-bear systems with strong nonlinear elements. One example, a single-spool rotating system with strong nonlinear elements, is given. The obtained results show that this method is superior to that of Gu and Chen (1990) in accuracy, stability, and economy.

  5. Source apportionment of trace element pollution in surface sediments using positive matrix factorization combined support vector machines: application to the Jinjiang River, China.

    PubMed

    Chen, Haiyang; Teng, Yanguo; Wang, Jinsheng; Song, Liuting; Zuo, Rui

    2013-03-01

    In this study, a method of positive matrix factorization (PMF) combined support vector machines (SVMs) was adopted to identify possible sources and apportion contributions for trace element pollution in surface sediments from the Jinjiang River, Southeastern China. Utilizing diagnostics tools, four significant factors were extracted from sediment samplers, which were collected in December 2010 at 15 different sites. By treating source identification as a pattern recognition problem, the factor loadings derived from PMF were classified by SVM classifiers which have been trained and validated with fingerprints of eight potential source categories. Using SVM, industrial wastewater from lead ore mining and metal handcraft manufacture, atmospheric deposition, and natural background were identified as main sources of trace element pollution in surface sediments from the Jinjiang River, which were affirmed by visually comparing compound patterns and the differences between the predicted and actual fractional compositions. Apportionment results showed that source of lead ore mining made the largest contribution (33.62 %), followed by atmospheric deposition (30.99 %), metal handcraft manufacture (30.09 %), and natural background (5.29 %).

  6. Matrix elements of intraband transitions in quantum dot intermediate band solar cells: the influence of quantum dot presence on the extended-state electron wave-functions

    NASA Astrophysics Data System (ADS)

    Nozawa, Tomohiro; Arakawa, Yasuhiko

    2014-04-01

    The intraband transitions which are essential for quantum dot intermediate band solar cells (QD IBSCs) are theoretically investigated by estimating the matrix elements from a ground bound state, which is often regarded as an intermediate band (IB), to conduction band (CB) states for a structure with a quantum dot (QD) embedded in a matrix (a QD/matrix structure). We have found that the QD pushes away the electron envelope functions (probability densities) from the QD region in almost all quantum states above the matrix CB minimum. As a result, the matrix elements of the intraband transitions in the QD/matrix structure are largely reduced, compared to those calculated assuming the envelope functions of free electrons (i.e., plane-wave envelope functions) in a matrix structure as the final states of the intraband transitions. The result indicates the strong influence of the QD itself on the intraband transitions from the IB to the CB states in QD IBSC devices. This work will help in better understanding the problem of the intraband transitions and give new insight, that is, engineering of quantum states is indispensable for the realization of QD IBSCs with high solar energy conversion efficiencies.

  7. The Potential Impacts on Aquatic Ecosystems from the Release of Trace Elements in Geothermal Fluids

    SciTech Connect

    Cushman, R.M.

    2000-03-14

    Geothermal energy will likely constitute an increasing percentage of our nation's future energy ''mix,'' both for electrical and nonelectrical uses. Associated with the exploitation of geothermal resources is the handling and disposal of fluids which contain a wide variety of potentially toxic trace elements. We present analyses of 14 trace elements found in hydrothermal fluids from various geothermal reservoirs in the western United States. The concentrations of these elements vary over orders of magnitude between reservoirs. Potential impacts are conservatively assessed on the basis of (1) toxicity to freshwater biota, and (2) bioaccumulation in food fish to the point where consumption might be hazardous to human health. Trace element concentrations generally range from benign levels to levels which might prove toxic to freshwater biota and contaminate food fisheries. We stress the need for site-specific analyses and careful handling of geothermal fluids in order to minimize potential impacts.

  8. Nuclear transition matrix elements for Majoron-accompanied neutrinoless double-β decay within a projected-Hartree-Fock-Bogoliubov model

    NASA Astrophysics Data System (ADS)

    Rath, P. K.; Chandra, R.; Chaturvedi, K.; Lohani, P.; Raina, P. K.

    2016-02-01

    The model-dependent uncertainties in the nuclear transition matrix elements for the Majoron-accompanied neutrinoless double-β decay (0+→0+transition) of Zr,9694, 100Mo, Te,130128, and 150Nd isotopes are calculated by employing the projected-Hartree-Fock-Bogoliubov formalism with four different parametrizations of the pairing plus multipolar two-body interactions and three different parametrizations of the Jastrow short-range correlations. Uncertainties in the nuclear transition matrix elements turn out to be less than 15% and 21% for decays involving the emission of single and double Majorons, respectively.

  9. Matrix metalloproteinase-3 gene promoter polymorphisms: A potential risk factor for pelvic organ prolapse

    PubMed Central

    Karachalios, Charalampos; Bakas, Panagiotis; Kaparos, Georgios; Demeridou, Styliani; Liapis, Ilias; Grigoriadis, Charalampos; Liapis, Aggelos

    2016-01-01

    Pelvic organ prolapse (POP) is a common multifactorial condition. Matrix metalloproteinases (MMPs) are enzymes capable of breaking down various connective tissue elements. Single-nucleotide polymorphisms (SNPs) in regulatory areas of MMP-encoding genes can alter their transcription rate, and therefore the possible effect on pelvic floor supporting structures. The insertion of an adenine (A) base in the promoter of the MMP-3 gene at position −1612/−1617 produces a sequence of six adenines (6A), whereas the other allele has five (5A). The aim of the present study was to investigate the possible association of MMP-3 gene promoter SNPs with the risk of POP. The patient group comprised 80 women with clinically significant POP [Stage II, III or IV; POP quantification (POP-Q) system]. The control group consisted of 80 females without any or important pelvic floor support defects (Stages 0 or I; POP-Q system). All the participants underwent the same preoperative evaluation. SNP detection was determined with whole blood sample DNA analysis by quantitative polymerase chain reaction (PCR) in LightCycler® PCR platforms, using the technique of sequence-specific hybridization probe-binding assays and melting temperature curve analysis. The results showed there was no statistically significant difference between 5A/5A, 5A/6A and 6A/6A MMP-3 gene promoter variants in the two study groups (P=0.4758). Therefore, MMP-3 gene promoter SNPs alone is insufficient to increase the genetic susceptibility to POP development. PMID:27588175

  10. Electrochemical sensor for dopamine based on imprinted silica matrix-poly(aniline boronic acid) hybrid as recognition element.

    PubMed

    Li, Jian; Zhang, Ning; Sun, Qingqing; Bai, Zhanming; Zheng, Jianbin

    2016-10-01

    A novel imprinted silica matrix-poly(aniline boronic acid) hybrid for electrochemical detection of dopamine (DA) was developed. Boronic acid functionalized conducting polymer was electrochemically prepared on Au electrode. The number of covalent binding sites toward DA templates was controlled by potential cycles. A precursory sol solution of ammonium fluorosilicate (as cross-linking monomer) containing DA was spin-coated on the polymer modified electrode. Under NH3 atmosphere, the hydroxyl ions were generated in the solution and catalyzed the hydrolysis of fluorosilicate to form silica matrix. After this aqueous sol-gel process, an inorganic framework around the DA template was formed and the imprinted hybrid for DA was also produced. As revealed by scanning electron microscopy, UV-vis spectroscopy and cyclic voltammetry characterization, DA was embedded in the imprinted hybrid successfully. The affinity and selectivity of the imprinted hybrid were also characterized by cyclic voltammetry. The imprinted hybrid showed higher affinity for DA than that for epinephrine, and little or no affinity for ascorbic acid and uric acid due to the combined effects of covalent interaction, cavities matching and electrostatic repulsion. The imprinted hybrid sensor exhibited a quick response (within 5min) to DA in the concentration range from 0.05 to 500μmolL(-1) with a detection limit of 0.018μmolL(-1). The prepared sensor was also applied to detect DA in real samples with a satisfactory result. PMID:27474321

  11. Potentially toxic element phytoavailability assessment in Technosols from former smelting and mining areas.

    PubMed

    Qasim, Bashar; Motelica-Heino, Mikael; Joussein, Emmanuel; Soubrand, Marilyne; Gauthier, Arnaud

    2015-04-01

    This study reports the chemical bioavailability of several potentially toxic elements (Zn, Pb, Cd, As, and Sb) in contaminated Technosols from two former smelting and mining areas. Though these elements have long been recognized as potentially harmful elements, understanding of their toxicity and environmental behavior in Technosols developed on former mining and smelting sites are more limited, particularly for As and Sb. Surface soils were sampled from metallophyte grassland contaminated with Zn, Pb, and Cd located at Mortagne-du-Nord (North France) and from a former mining settling basin contaminated with As, Pb, and Sb located at la Petite Faye (Limoges, France). Various selective single extraction procedures (CaCl2, NaNO3, NH4NO3, DTPA, and EDTA) were used together with germination tests with dwarf beans whose shoots were analyzed for their potentially toxic element concentrations after 21 days of growth. The extraction capacity of the potentially toxic elements followed the order EDTA > DTPA > NH4NO3 > CaCl2 > NaNO3 for both studied areas. Pearson's correlation coefficient analysis between the concentrations of potentially toxic elements accumulated in bean primary leaves or their mineral mass with their extractable concentrations showed a positive significant correlation with dilute CaCl2 and nitrate solutions extraction procedures. In contrast, for all studied elements, except Pb, the complexing and chelating extractants (EDTA and DTPA) exhibited poor correlation with the dwarf bean leaves concentrations. Moreover, results showed that the 0.01 M CaCl2 extraction procedure was the most suitable and provided the most useful indications of metal phytoavailability for studied elements.

  12. Internal one-particle density matrix for Bose-Einstein condensates with finite number of particles in a harmonic potential

    SciTech Connect

    Yamada, Taiichi; Funaki, Yasuro; Horiuchi, Hisashi; Roepke, Gerd; Schuck, Peter; Tohsaki, Akihiro

    2009-05-15

    Investigations on the internal one-particle density matrix in the case of Bose-Einstein condensates with a finite number (N) of particles in a harmonic potential are performed. We solve the eigenvalue problem of the Pethick-Pitaevskii-type internal density matrix and find a fragmented condensate. On the contrary the condensate Jacobi-type internal density matrix gives complete condensation into a single state. The internal one-particle density matrix is, therefore, shown to be different in general for different choices of the internal coordinate system. We propose two physically motivated criteria for the choice of the adequate coordinate systems that give us a unique answer for the internal one-particle density matrix. One criterion is that in the infinite particle number limit (N={infinity}) the internal one-particle density matrix should have the same eigenvalues and eigenfunctions as those of the corresponding ideal Bose-Einstein condensate in the laboratory frame. The other criterion is that the coordinate of the internal one-particle density matrix should be orthogonal to the remaining (N-2) internal coordinates, though the (N-2) coordinates, in general, do not need to be mutually orthogonal. This second criterion is shown to imply the first criterion. It is shown that the internal Jacobi coordinate system satisfies these two criteria while the internal coordinate system adopted by Pethick and Pitaevskii for the construction of the internal one-particle density matrix does not. It is demonstrated that these two criteria uniquely determine the internal one-particle density matrix that is identical to that calculated with the Jacobi coordinates. The relevance of this work concerning {alpha}-particle condensates in nuclei, as well as bosonic atoms in traps, is pointed out.

  13. Plasma gelsolin and matrix metalloproteinase 3 as potential biomarkers for Alzheimer disease.

    PubMed

    Peng, Mao; Jia, Jianping; Qin, Wei

    2015-05-19

    Gelsolin (GSN) levels and matrix metalloproteinase 3 (MMP3) activity have been found to be altered in the plasma in patients with Alzheimer disease (AD). The aim of this study was to determine whether a combination of these proteins with clinical data is specific and sensitive enough for AD diagnosis. In 113 non-demented controls and 113 patients with probable AD, the plasma GSN levels were determined using the enzyme-linked immunosorbent assay (ELISA), and the plasma MMP3 activity was determined using casein zymography. Logistic regression and receiver operating characteristic (ROC) curve analysis were used to determine the diagnostic accuracy of these proteins combined with clinical data. Compared with the controls, the AD patients had significantly lower GSN levels and significantly higher MMP3 activity. Moreover, both the GSN level and MMP3 activity were significantly correlated with the MMSE scores. In AD patients, the GSN level was negatively correlated with MMP3 activity. ROC curve analysis showed that the specificity and sensitivity were 77% and 75.2%, respectively, for the combination of the following candidate biomarkers: GSN level/the total amount of Aβ42 and Aβ40, plasma MMP3 activity and clinical data. With its relatively high sensitivity and specificity, this combined biomarker panel may have potential for the screening of AD patients.

  14. A Regularized Galerkin Boundary Element Method (RGBEM) for Simulating Potential Flow About Zero Thickness Bodies

    SciTech Connect

    GHARAKHANI,ADRIN; WOLFE,WALTER P.

    1999-10-01

    The prediction of potential flow about zero thickness membranes by the boundary element method constitutes an integral component of the Lagrangian vortex-boundary element simulation of flow about parachutes. To this end, the vortex loop (or the panel) method has been used, for some time now, in the aerospace industry with relative success [1, 2]. Vortex loops (with constant circulation) are equivalent to boundary elements with piecewise constant variation of the potential jump. In this case, extending the analysis in [3], the near field potential velocity evaluations can be shown to be {Omicron}(1). The accurate evaluation of the potential velocity field very near the parachute surface is particularly critical to the overall accuracy and stability of the vortex-boundary element simulations. As we will demonstrate in Section 3, the boundary integral singularities, which arise due to the application of low order boundary elements, may lead to severely spiked potential velocities at vortex element centers that are near the boundary. The spikes in turn cause the erratic motion of the vortex elements, and the eventual loss of smoothness of the vorticity field and possible numerical blow up. In light of the arguments above, the application of boundary elements with (at least) a linear variation of the potential jump--or, equivalently, piecewise constant vortex sheets--would appear to be more appropriate for vortex-boundary element simulations. For this case, two strategies are possible for obtaining the potential flow field. The first option is to solve the integral equations for the (unknown) strengths of the surface vortex sheets. As we will discuss in Section 2.1, the challenge in this case is to devise a consistent system of equations that imposes the solenoidality of the locally 2-D vortex sheets. The second approach is to solve for the unknown potential jump distribution. In this case, for commonly used C{sup o} shape functions, the boundary integral is singular at

  15. A fiber matrix model for fluid flow and streaming potentials in the canaliculi of an osteon

    NASA Technical Reports Server (NTRS)

    Zeng, Y.; Cowin, S. C.; Weinbaum, S.

    1994-01-01

    A theoretical model is developed to predict the fluid shear stress and streaming potential at the surface of osteocytic processes in the lacunar-canalicular porosity of an osteon when the osteon is subject to mechanical loads that are parallel or perpendicular to its axis. The theory developed in Weinbaum et al. (31) for the flow through a proteoglycan matrix in a canaliculus is employed in a poroelastic model for the osteon. Our formulation is a generalization of that of Petrov et al. (17). Our model predicts that, in order to satisfy the measured frequency dependence of the phase and magnitude of the SGP in macroscopic bone samples, the fiber spacing in the fluid annulus must lie in the narrow range 6-7 nm typical of the spacing of GAG sidechains along a protein monomer. The model predictions for the local SGP profiles in the osteon agree with the experimental observations of Starkebaum et al. (24). The theory predicts that the pore pressure relaxation time, tau d, for a 150-300 microns diameter osteon with the foregoing matrix structure is approximately 0.03-0.13 sec, and that the amplitude of the mean fluid shear stress on the membrane of the osteocytic process at the mean areal radius of the osteon has a maximum at 28 Hz if tau d = 0.06 sec. This maximum, which is independent of the magnitude of the loading, could be important in vivo since the recent experiments of Turner et al. (28) and McLeod et al. (15) have a peak in the strain frequency spectrum between 20 and 30 Hz that also appears to be independent of the type (magnitude) of loading. Numerical predictions for the amplitude of the average fluid shear stress on the osteocytic membrane at the mean areal radius of the osteon show that the fluid shear stress associated with the low amplitude 20-30 Hz spectral strain component is at least as large as the average fluid shear stress associated with the high amplitude 1 Hz stride component, although the latter loading is an order of magnitude larger, and has a

  16. Determinations of the matrix element V(ub) from inclusive semileptonic B decays with reduced model dependency

    NASA Astrophysics Data System (ADS)

    Hill, Edward J.

    This thesis presents several measurements of the CKM quark mixing matrix element |Vub| with reduced theoretical model dependency. The data sample for these results consists of about 90 million Upsilon(4 S) → BB¯ decays collected between 1999 and 2002 with the BABAR detector at the PEP-II asymmetric-energy e+e- collider, located at the Stanford Linear Accelerator Center. The determinations of | Vub| are performed by measuring the invariant hadronic mass spectrum from inclusive semileptonic B meson decays recoiling from a fully reconstructed B meson decaying hadronically. In one method, the partial rate extracted from the charmless semileptonic hadronic mass spectrum below 1.67 GeV/c2 is combined with a weighted integral over the endpoint of the photon energy spectrum from b → sgamma decays and the result |Vub| = (4.43 +/- 0.38stat +/- 0.25syst +/- 0.28theo ) x 10-3 is obtained. In a second method, the charmless hadronic mass spectrum is measured up to 2.50 GeV/c 2, corresponding to 96.5% of the simulated hadronic mass spectrum. The charmless semileptonic branching fraction is deduced from this measurement and results in B (B¯ → Xuℓ n¯ ) = (1.64 +/- 0.60stat +/- 0.25 syst) x 10-3 which yields |V ub| = (3.84 +/- 0.70stat +/- 0.30syst +/- 0.19theo) x 10-3.

  17. Matrix attachment region elements have small and variable effects on transgene expression and stability in field-grown Populus.

    PubMed

    Li, Jingyi; Brunner, Amy M; Meilan, Richard; Strauss, Steven H

    2008-12-01

    Matrix attachment regions (MARs) are thought to buffer transgenes from the influence of surrounding chromosomal sequences, and therefore to reduce transgene silencing and variation in expression. The statistical properties of more than 400 independent transgenic events produced in Populus, with and without flanking MAR elements from the tobacco root gene RB7, were analysed. The expression of two reporter genes in two poplar clones during three phases of vegetative growth, and the association of T-DNA characteristics with expression, was examined. It was found that MARs did not show a consistent effect on transgene expression levels; they had no effect on the green fluorescent protein (GFP) reporter gene, but reduced expression in the Basta resistance (BAR) reporter gene by 23%. The presence of MARs reduced expression variability within transformant populations, apparently by reducing the number of silenced or weakly expressing events. Transgene expression was highly stable over vegetative growth cycles that spanned 3 years of growth in the glasshouse and field, but MARs showed no association with the strength of correlations in expression over the years. Nonetheless, MARs increased the correlation in expression between a p35S::GFP and prbcS::BAR transgene linked on the same vector, but the effect was small and varied between the years. The presence of MARs had no effect on the transgene copy number, but was positively associated with T-DNA truncations, as well as with the formation of direct over inverted repeats at the same chromosomal locus. PMID:19548343

  18. A measurement of the top quark mass in 1.96 TeV proton-antiproton collisions using a novel matrix element method

    SciTech Connect

    Freeman, John C

    2007-01-01

    A measurement of the top quark mass in t$\\bar{t}$ → l + jets candidate events, obtained from p$\\bar{p}$ collisions at √s = 1.96 TeV at the Fermilab Tevatron using the CDF II detector, is presented. The measurement approach is that of a matrix element method. For each candidate event, a two dimensional likelihood is calculated in the top pole mass and a constant scale factor, 'JES', where JES multiplies the input particle jet momenta and is designed to account for the systematic uncertainty of the jet momentum reconstruction. As with all matrix elements techniques, the method involves an integration using the Standard Model matrix element for tt production and decay. however, the technique presented is unique in that the matrix element is modified to compensate for kinematic assumptions which are made to reduce computation time. Background events are dealt with through use of an event observable which distinguishes signal from background, as well as through a cut on the value of an event's maximum likelihood. Results are based on a 955 pb-1 data sample, using events with a high-pT lepton and exactly four high-energy jets, at least one of which is tagged as coming from a b quark; 149 events pass all the selection requirements. They find Mmeas = 169.8 ± 2.3(stat.) ± 1.4(syst.) GeV/c2.

  19. A Measurement of the Top Quark Mass in 1.96 TeV Proton-Antiproton Collisions Using a Novel Matrix Element Method

    SciTech Connect

    Freeman, John

    2007-01-01

    A measurement of the top quark mass in t$\\bar{t}$ → l + jets candidate events, obtained from p$\\bar{p}$ collisions at √s = 1.96 TeV at the Fermilab Tevatron using the CDF II detector, is presented. The measurement approach is that of a matrix element method. For each candidate event, a two dimensional likelihood is calculated in the top pole mass and a constant scale factor, 'JES', where JES multiplies the input particle jet momenta and is designed to account for the systematic uncertainty of the jet momentum reconstruction. As with all matrix element techniques, the method involves an integration using the Standard Model matrix element for t$\\bar{t}$ production and decay. However, the technique presented is unique in that the matrix element is modified to compensate for kinematic assumptions which are made to reduce computation time. Background events are dealt with through use of an event observable which distinguishes signal from background, as well as through a cut on the value of an event's maximum likelihood. Results are based on a 955 pb-1 data sample, using events with a high-pT lepton and exactly four high-energy jets, at least one of which is tagged as coming from a b quark; 149 events pass all the selection requirements. They find Mmeas = 169.8 ± 2.3(stat.) ± 1.4(syst.) GeV/c2.

  20. Influence of soil texture on nutrients and potentially hazardous elements in Eremanthus erythropappus.

    PubMed

    Figueiredo, Maurilio Assis; Leite, Mariangela Garcia Praça; Kozovits, Alessandra Rodrigues

    2016-01-01

    Understanding the factors that control uptake rates and allocation of chemical elements among plant organs is a fundamental prerequisite to improve phytostabilization techniques of hazardous elements in contaminated areas. The present study shows evidence that different substrate textures (coarse and fine laterite) do not significantly change the partitioning of root and shoot dry biomass and with few exceptions, do not significantly affect the final average concentration of elements in Eremanthus erythropappus, but change the root:shoot allocation of both essential nutrients and elements potentially toxic to biota. Growth on coarse laterite resulted in significant higher K (30%), Mg (34%), P (25%), S (32%), Cu (58%), and Na (43%) concentrations in roots and lower Cd concentration (29%). In shoots, coarse laterite led to reduction in K, Fe, Al, and Cr and increase in Na and Sr concentrations. Changes in element allocation could be, in part, a result of differences in the water availability of substrates. Matric potential in coarse laterite was significantly lower in at least 47% of the days analyzed throughout the year. Changes in element phytoextraction or phytostabilization potential could influence the efficiency of rehabilitation projects in areas degraded by mining activities. PMID:26588605

  1. Influence of soil texture on nutrients and potentially hazardous elements in Eremanthus erythropappus.

    PubMed

    Figueiredo, Maurilio Assis; Leite, Mariangela Garcia Praça; Kozovits, Alessandra Rodrigues

    2016-01-01

    Understanding the factors that control uptake rates and allocation of chemical elements among plant organs is a fundamental prerequisite to improve phytostabilization techniques of hazardous elements in contaminated areas. The present study shows evidence that different substrate textures (coarse and fine laterite) do not significantly change the partitioning of root and shoot dry biomass and with few exceptions, do not significantly affect the final average concentration of elements in Eremanthus erythropappus, but change the root:shoot allocation of both essential nutrients and elements potentially toxic to biota. Growth on coarse laterite resulted in significant higher K (30%), Mg (34%), P (25%), S (32%), Cu (58%), and Na (43%) concentrations in roots and lower Cd concentration (29%). In shoots, coarse laterite led to reduction in K, Fe, Al, and Cr and increase in Na and Sr concentrations. Changes in element allocation could be, in part, a result of differences in the water availability of substrates. Matric potential in coarse laterite was significantly lower in at least 47% of the days analyzed throughout the year. Changes in element phytoextraction or phytostabilization potential could influence the efficiency of rehabilitation projects in areas degraded by mining activities.

  2. Plant-soil distribution of potentially toxic elements in response to elevated atmospheric CO2.

    PubMed

    Duval, Benjamin D; Dijkstra, Paul; Natali, Susan M; Megonigal, J Patrick; Ketterer, Michael E; Drake, Bert G; Lerdau, Manuel T; Gordon, Gwyneth; Anbar, Ariel D; Hungate, Bruce A

    2011-04-01

    The distribution of contaminant elements within ecosystems is an environmental concern because of these elements' potential toxicity to animals and plants and their ability to hinder microbial ecosystem services. As with nutrients, contaminants are cycled within and through ecosystems. Elevated atmospheric CO2 generally increases plant productivity and alters nutrient element cycling, but whether CO2 causes similar effects on the cycling of contaminant elements is unknown. Here we show that 11 years of experimental CO2 enrichment in a sandy soil with low organic matter content causes plants to accumulate contaminants in plant biomass, with declines in the extractable contaminant element pools in surface soils. These results indicate that CO2 alters the distribution of contaminant elements in ecosystems, with plant element accumulation and declining soil availability both likely explained by the CO2 stimulation of plant biomass. Our results highlight the interdependence of element cycles and the importance of taking a broad view of the periodic table when the effects of global environmental change on ecosystem biogeochemistry are considered.

  3. Event-related potentials in a moving matrix modification of the P300 brain-computer interface paradigm.

    PubMed

    Shishkin, Sergei L; Ganin, Ilya P; Kaplan, Alexander Ya

    2011-06-01

    In the standard design of the brain-computer interfaces (BCI) based on the P300 component of the event-related potentials (ERP), target and non-target stimuli are presented at fixed positions in a motionless matrix. Can we let this matrix be moving (e.g., if attached to a robot) without loosing the efficiency of BCI? We assessed changes of the positive peak at Pz in the time interval 300-500 ms after the stimulus onset (P300) and the negative peak at the occipital electrodes in the range 140-240 ms (N1), both important for the operation of the P300 BCI, during fixating a target cell of a moving matrix in healthy participants (n=12). N1 amplitude in the difference (target-non-target) waveforms decreased with the velocity, although remained high (M=-4.3, SD=2.1) even at highest velocity (20°/s). In general, the amplitudes and latencies of these ERP components were remarkably stable in studied types of matrix movement and all velocities of horizontal movement (5, 10 and 20°/s) comparing to matrix in fixed position. These data suggest that, for the users controlling their gaze, the P300 BCI design can be extended to modifications requiring stimuli matrix motion.

  4. Assessment of antimicrobial resistance transfer between lactic acid bacteria and potential foodborne pathogens using in vitro methods and mating in a food matrix.

    PubMed

    Toomey, Niamh; Monaghan, Aine; Fanning, Séamus; Bolton, Declan J

    2009-10-01

    The transferability of antimicrobial resistance from lactic acid bacteria (LAB) to potential pathogenic strains was studied using in vitro methods and mating in a food matrix. Five LAB donors containing either erythromycin or tetracycline resistance markers on transferable elements were conjugally mated with LAB (Enterococcus faecalis, Lactococcus lactis) and pathogenic strains (Listeria spp., Salmonella ssp., Staphylococcus aureus, and Escherichia coli). In vitro transfer experiments were carried out with the donors and recipients using both the filter and plate mating methods. The food matrix consisted of fermented whole milk (fermented with the LAB donors) with the pathogenic recipients added as contaminants during the production process. All transconjugants were confirmed by phenotypic and molecular methods. Erythromycin resistance transfer from LAB strains to Listeria spp. was observed using both in vitro mating methods at high transfer frequencies of up to 5.1 x 10(-4) transconjugants per recipient. Also, high frequency transfer (ranging from 2.7 x 10(-8) up to 1.1 x 10(-3) transconjugants per recipient) of both erythromycin and tetracycline-resistance was observed between LAB species using in vitro methods. No resistance transfer was observed to Salmonella spp., Staphylococcus aureus, and E. coli. The only conjugal transfer observed in the fermented milk matrix was for tetracycline resistance between two LAB strains (at a transfer frequency of 2.6 x 10(-7) transconjugants per recipients). This study demonstrates the transfer of antimicrobial resistance from LAB to Listeria spp. using in vitro methods and also the transfer of resistance between LAB species in a food matrix. It highlights the involvement of LAB as a potential source of resistance determinants that may be disseminated between LAB and pathogenic strains including Listeria spp. Furthermore, it indicates that food matrices such as fermented milks may provide a suitable environment to support gene

  5. [Evoked Potential Blind Extraction Based on Fractional Lower Order Spatial Time-Frequency Matrix].

    PubMed

    Long, Junbo; Wang, Haibin; Zha, Daifeng

    2015-04-01

    The impulsive electroencephalograph (EEG) noises in evoked potential (EP) signals is very strong, usually with a heavy tail and infinite variance characteristics like the acceleration noise impact, hypoxia and etc., as shown in other special tests. The noises can be described by a stable distribution model. In this paper, Wigner-Ville distribution (WVD) and pseudo Wigner-Ville distribution (PWVD) time-frequency distribution based on the fractional lower order moment are presented to be improved. We got fractional lower order WVD (FLO-WVD) and fractional lower order PWVD (FLO-PWVD) time-frequency distribution which could be suitable for a stable distribution process. We also proposed the fractional lower order spatial time-frequency distribution matrix (FLO-STFM) concept. Therefore, combining with time-frequency underdetermined blind source separation (TF-UBSS), we proposed a new fractional lower order spatial time-frequency underdetermined blind source separation (FLO-TF-UBSS) which can work in a stable distribution environment. We used the FLO-TF-UBSS algorithm to extract EPs. Simulations showed that the proposed method could effectively extract EPs in EEG noises, and the separated EPs and EEG signals based on FLO-TF-UBSS were almost the same as the original signal, but blind separation based on TF-UBSS had certain deviation. The correlation coefficient of the FLO-TF-UBSS algorithm was higher than the TF-UBSS algorithm when generalized signal-to-noise ratio (GSNR) changed from 10 dB to 30 dB and a varied from 1. 06 to 1. 94, and was approximately e- qual to 1. Hence, the proposed FLO-TF-UBSS method might be better than the TF-UBSS algorithm based on second order for extracting EP signal under an EEG noise environment. PMID:26211238

  6. Thick Acellular Heart Extracellular Matrix with Inherent Vasculature: A Potential Platform for Myocardial Tissue Regeneration

    PubMed Central

    Sarig, Udi; Au-Yeung, Gigi C.T.; Wang, Yao; Bronshtein, Tomer; Dahan, Nitsan; Boey, Freddy Y.C.; Venkatraman, Subbu S.

    2012-01-01

    The decellularization of porcine heart tissue offers many opportunities for the production of physiologically relevant myocardial mimetic scaffolds. Earlier, we reported the successful isolation of a thin porcine cardiac extracellular matrix (pcECM) exhibiting relevant bio-mechanical properties for myocardial tissue engineering. Nevertheless, since native cardiac tissue is much thicker, such thin scaffolds may offer limited regeneration capacity. However, generation of thicker myocardial mimetic tissue constructs is hindered by diffusion limitations (∼100 μm), and the lack of a proper vascular-like network within these constructs. In our present work, we focused on optimizing the decellularization procedure for thicker tissue slabs (10–15 mm), while retaining their inherent vasculature, and on characterizing the resulting pcECM. The trypsin/Triton-based perfusion procedure that resulted in a nonimmunogenic and cell-supportive pcECM was found to be more effective in cell removal and in the preservation of fiber morphology and structural characteristics than stirring, sonication, or sodium dodecyl sulfate/Triton-based procedures. Mass spectroscopy revealed that the pcECM is mainly composed of ECM proteins with no apparent cellular protein remains. Mechanical testing indicated that the obtained pcECM is viscoelastic in nature and possesses the typical stress-strain profile of biological materials. It is stiffer than native tissue yet exhibits matched mechanical properties in terms of energy dissipation, toughness, and ultimate stress behavior. Vascular network functionality was maintained to the first three–four branches from the main coronary vessels. Taken together, these results reaffirm the efficiency of the decellularization procedure reported herein for yielding thick nonimmunogenic cell-supportive pcECM scaffolds, preserving both native tissue ultra-structural properties and an inherent vascular network. When reseeded with the appropriate progenitor

  7. Extracellular matrix protein in calcified endoskeleton: a potential additive for crystal growth and design

    NASA Astrophysics Data System (ADS)

    Azizur Rahman, M.; Fujimura, Hiroyuki; Shinjo, Ryuichi; Oomori, Tamotsu

    2011-06-01

    In this study, we demonstrate a key function of extracellular matrix proteins (ECMPs) on seed crystals, which are isolated from calcified endoskeletons of soft coral and contain only CaCO 3 without any living cells. This is the first report that an ECMP protein extracted from a marine organism could potentially influence in modifying the surface of a substrate for designing materials via crystallization. We previously studied with the ECMPs from a different type of soft coral ( Sinularia polydactyla) without introducing any seed crystals in the process , which showed different results. Thus, crystallization on the seed in the presence of ECMPs of present species is an important first step toward linking function to individual proteins from soft coral. For understanding this interesting phenomenon, in vitro crystallization was initiated in a supersaturated solution on seed particles of calcite (1 0 4) with and without ECMPs. No change in the crystal growth shape occurred without ECMPs present during the crystallization process. However, with ECMPs, the morphology and phase of the crystals in the crystallization process changed dramatically. Upon completion of crystallization with ECMPs, an attractive crystal morphology was found. Scanning electron microscopy (SEM) was utilized to observe the crystal morphologies on the seeds surface. The mineral phases of crystals nucleated by ECMPs on the seeds surface were examined by Raman spectroscopy. Although 50 mM Mg 2+ is influential in making aragonite in the crystallization process, the ECMPs significantly made calcite crystals even when 50 mM Mg 2+ was present in the process. Crystallization with the ECMP additive seems to be a technically attractive strategy to generate assembled micro crystals that could be used in crystals growth and design in the Pharmaceutical and biotechnology industries.

  8. Analysis of superconducting electromagnetic finite elements based on a magnetic vector potential variational principle

    NASA Technical Reports Server (NTRS)

    Schuler, James J.; Felippa, Carlos A.

    1991-01-01

    Electromagnetic finite elements are extended based on a variational principle that uses the electromagnetic four potential as primary variable. The variational principle is extended to include the ability to predict a nonlinear current distribution within a conductor. The extension of this theory is first done on a normal conductor and tested on two different problems. In both problems, the geometry remains the same, but the material properties are different. The geometry is that of a 1-D infinite wire. The first problem is merely a linear control case used to validate the new theory. The second problem is made up of linear conductors with varying conductivities. Both problems perform well and predict current densities that are accurate to within a few ten thousandths of a percent of the exact values. The fourth potential is then removed, leaving only the magnetic vector potential, and the variational principle is further extended to predict magnetic potentials, magnetic fields, the number of charge carriers, and the current densities within a superconductor. The new element produces good results for the mean magnetic field, the vector potential, and the number of superconducting charge carriers despite a relatively high system condition number. The element did not perform well in predicting the current density. Numerical problems inherent to this formulation are explored and possible remedies to produce better current predicting finite elements are presented.

  9. Achieving Finite Element Mesh Quality via Optimization of the Jacobian Matrix Norm and Associated Quantities, Part II - A Framework for Volume Mesh Optimization and the Condition Number of the Jacobian Matrix

    SciTech Connect

    Knupp, P.M.

    1999-03-26

    Three-dimensional unstructured tetrahedral and hexahedral finite element mesh optimization is studied from a theoretical perspective and by computer experiments to determine what objective functions are most effective in attaining valid, high quality meshes. The approach uses matrices and matrix norms to extend the work in Part I to build suitable 3D objective functions. Because certain matrix norm identities which hold for 2 x 2 matrices do not hold for 3 x 3 matrices. significant differences arise between surface and volume mesh optimization objective functions. It is shown, for example, that the equivalence in two-dimensions of the Smoothness and Condition Number of the Jacobian matrix objective functions does not extend to three dimensions and further. that the equivalence of the Oddy and Condition Number of the Metric Tensor objective functions in two-dimensions also fails to extend to three-dimensions. Matrix norm identities are used to systematically construct dimensionally homogeneous groups of objective functions. The concept of an ideal minimizing matrix is introduced for both hexahedral and tetrahedral elements. Non-dimensional objective functions having barriers are emphasized as the most logical choice for mesh optimization. The performance of a number of objective functions in improving mesh quality was assessed on a suite of realistic test problems, focusing particularly on all-hexahedral ''whisker-weaved'' meshes. Performance is investigated on both structured and unstructured meshes and on both hexahedral and tetrahedral meshes. Although several objective functions are competitive, the condition number objective function is particularly attractive. The objective functions are closely related to mesh quality measures. To illustrate, it is shown that the condition number metric can be viewed as a new tetrahedral element quality measure.

  10. Nonorthogonal orbital based N-body reduced density matrices and their applications to valence bond theory. I. Hamiltonian matrix elements between internally contracted excited valence bond wave functions.

    PubMed

    Chen, Zhenhua; Chen, Xun; Wu, Wei

    2013-04-28

    In this series, the n-body reduced density matrix (n-RDM) approach for nonorthogonal orbitals and their applications to ab initio valence bond (VB) methods are presented. As the first paper of this series, Hamiltonian matrix elements between internally contracted VB wave functions are explicitly provided by means of nonorthogonal orbital based RDM approach. To this end, a more generalized Wick's theorem, called enhanced Wick's theorem, is presented both in arithmetical and in graphical forms, by which the deduction of expressions for the matrix elements between internally contracted VB wave functions is dramatically simplified, and the matrix elements are finally expressed in terms of tensor contractions of electronic integrals and n-RDMs of the reference VB self-consistent field wave function. A string-based algorithm is developed for the purpose of evaluating n-RDMs in an efficient way. Using the techniques presented in this paper, one is able to develop new methods and efficient algorithms for nonorthogonal orbital based many-electron theory much easier than by use of the first quantized formulism.

  11. Nonorthogonal orbital based N-body reduced density matrices and their applications to valence bond theory. I. Hamiltonian matrix elements between internally contracted excited valence bond wave functions

    NASA Astrophysics Data System (ADS)

    Chen, Zhenhua; Chen, Xun; Wu, Wei

    2013-04-01

    In this series, the n-body reduced density matrix (n-RDM) approach for nonorthogonal orbitals and their applications to ab initio valence bond (VB) methods are presented. As the first paper of this series, Hamiltonian matrix elements between internally contracted VB wave functions are explicitly provided by means of nonorthogonal orbital based RDM approach. To this end, a more generalized Wick's theorem, called enhanced Wick's theorem, is presented both in arithmetical and in graphical forms, by which the deduction of expressions for the matrix elements between internally contracted VB wave functions is dramatically simplified, and the matrix elements are finally expressed in terms of tensor contractions of electronic integrals and n-RDMs of the reference VB self-consistent field wave function. A string-based algorithm is developed for the purpose of evaluating n-RDMs in an efficient way. Using the techniques presented in this paper, one is able to develop new methods and efficient algorithms for nonorthogonal orbital based many-electron theory much easier than by use of the first quantized formulism.

  12. Nonorthogonal orbital based N-body reduced density matrices and their applications to valence bond theory. I. Hamiltonian matrix elements between internally contracted excited valence bond wave functions.

    PubMed

    Chen, Zhenhua; Chen, Xun; Wu, Wei

    2013-04-28

    In this series, the n-body reduced density matrix (n-RDM) approach for nonorthogonal orbitals and their applications to ab initio valence bond (VB) methods are presented. As the first paper of this series, Hamiltonian matrix elements between internally contracted VB wave functions are explicitly provided by means of nonorthogonal orbital based RDM approach. To this end, a more generalized Wick's theorem, called enhanced Wick's theorem, is presented both in arithmetical and in graphical forms, by which the deduction of expressions for the matrix elements between internally contracted VB wave functions is dramatically simplified, and the matrix elements are finally expressed in terms of tensor contractions of electronic integrals and n-RDMs of the reference VB self-consistent field wave function. A string-based algorithm is developed for the purpose of evaluating n-RDMs in an efficient way. Using the techniques presented in this paper, one is able to develop new methods and efficient algorithms for nonorthogonal orbital based many-electron theory much easier than by use of the first quantized formulism. PMID:23635123

  13. Positive Matrix Factorization of hourly size-segregated PM elemental concentration at a street canyon: effect of street cleaning

    NASA Astrophysics Data System (ADS)

    Amato, Fulvio; Nava, Silvia; Lucarelli, Franco; Querol, Xavier; Alastuey, Andrés.

    2010-05-01

    Despite the high environmental and health burden of road dust emissions in urban environments, there is still a dearth of knowledge on the effectiveness of some possible remediation measures such as street cleaning activities. As a consequence of the recent notification from the EU commission for the exceedances of PM limit values (1999/30/EC), several EU countries (Austria, Germany and UK among others) have introduced street cleaning as one of the main measures to be taken in order to meet these limits in the next future. Nevertheless, the effectiveness of street cleaning is still far from being definitively determined since only few tests have been carried out so far and with very different local conditions. An intensive campaign was carried out during spring 2009 in the city centre of Barcelona (NE of Spain) by means of the application of innovative techniques: i) the hourly elemental composition of size segregated PM was used to investigate short term variability of specific tracers of road dust resuspension; ii) a Positive Matrix Factorization was applied in order to identify the daily pattern of each PM source. Hourly elemental concentrations were obtained by a two-stage streaker sampler, where particles are separated on different stages: an impactor deposits the aerosol coarse fraction (aerodynamic diameter between 2.5-10 µm) on a Kapton foil while the fine fraction (<2.5 µm) is collected on a Nuclepore filter having 0.4 µm pores. The two collecting plates (Kapton and Nuclepore) are paired on a cartridge which rotates at constant speed for a week: this produces a circular continuous deposition of particulate matter (streak) on both stages. Totally 349 samples were collected onto three pairs of stages and analyzed by Proton Induced X-Ray Emission (PIXE) external beam facility in Florence, based on a Van de Graaff accelerator. This facility has been used several times in the past for aerosol studies. A Positive Matrix Factorization (PMF) model was applied

  14. Investigation of the behavior of potentially hazardous trace elements in Kentucky coals and combustion byproducts

    SciTech Connect

    Robertson, J.D.; Blanchard, L.J.; Srikantapura, S.; Parekh, B.K.; Lafferty, C.J.

    1996-12-31

    The minor- and trace-element content of coal is of great interest because of the potentially hazardous impact on human health and the environment resulting from their release during coal combustion. Of the one billion tons of coal mined annually in the United States, 85-90% is consumed by coal-fired power plants. Potentially toxic elements present at concentrations as low as a few egg can be released in large quantities from combustion of this magnitude. Of special concern are those trace elements that occur naturally in coal which have been designated as potential hazardous air pollutants (HAPs) in the 1990 Amendments to the Clean Air Act. The principle objective of this work was to investigate a combination of physical and chemical coal cleaning techniques to remove 90 percent of HAP trace elements at 90 percent combustibles recovery from Kentucky No. 9 coal. Samples of this coal were first subjected to physical separation by flotation in a Denver cell. The float fraction from the Denver cell was then used as feed material for hydrothermal leaching tests in which the efficacy of dilute alkali (NaOH) and acid (HNO{sub 3}) solutions at various temperatures and pressures was investigated. The combined column flotation and mild chemical cleaning strategy removed 60-80% of trace elements with greater than 85, recovery of combustibles from very finely ground (-325 mesh) coal. The elemental composition of the samples generated at each stage was determined using particle induced X-ray emission (PIXE) analysis. PIXE is a rapid, instrumental technique that, in principle, is capable of analyzing all elements from sodium through uranium with sensitivities as low as 1 {mu}g/g.

  15. Grounded or submerged bulk carrier: the potential for leaching of coal trace elements to seawater.

    PubMed

    Lucas, Steven Andrew; Planner, John

    2012-05-01

    This study investigates the potential for leaching of coal trace elements to seawater from a grounded bulk carrier. The coal type and ecological scenario was based on the grounding of the "Shen Neng" (April 2010) at Douglas Shoal located within the Great Barrier Reef (Queensland, Australia). The area is of high ecological value and the Queensland Water Quality Guidelines (2009) provided threshold limits to interpret potential impacts. Coal contains many trace elements that are of major and moderate concern to human health and the environment although many of these concerns are only realised when coal is combusted. However, "unburnt" coal contains trace elements that may be leached to natural waterways and few studies have investigated the potential ecological impact of such an occurrence. For example, coal maritime transport has increased by almost 35% over the last five reported years (Jaffrennou et al., 2007) and as a result there is an increased inherent risk of bulk carrier accidents. Upon grounding or becoming submerged, coal within a bulk carrier may become saturated with seawater and potentially leach trace elements to the environment and impact on water quality and ecological resilience. The worst case scenario is the breakup of a bulk carrier and dispersal of cargo to the seafloor. PMID:22417390

  16. First measurements of the {rho}{sup 3} spin density matrix elements in {gamma}p --> p {omega} using CLAS at JLAB

    SciTech Connect

    Vernarsky, Brian J.

    2014-01-01

    In an effort towards a ''complete'' experiment for the ω meson, we present studies from an experiment with an unpolarized target and a circularly polarized photon beam (g1c), carried out using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. The experiment was analyzed using an extended maximum likelihood fit with partial wave amplitudes. New likelihood functions were calculated to account for the polarization of the photon beam. Both circular and linear polarizations are explored. The results of these fits are then used to project out the spin density matrix for the {omega}. First measurements of the {rho}{sup 3} spin density matrix elements will be presented using this method.

  17. Major and trace element geochemistry of Archean sulfidic black shale horizons as a potential vectoring tool for VMS exploration

    NASA Astrophysics Data System (ADS)

    Chapman, J. B.; Peter, J. M.; Layton-Matthews, D.; Gemmell, J. B.

    2009-05-01

    Metalliferous black shale horizons are a common but minor component of many subaqueous volcanic successions. These horizons are commonly drilled during volcanogenic massive sulfide (VMS) deposit exploration programs. Although ore metal enrichment can be identified by conventional assay methods, matrix dilution and post-burial hydrothermal and metamorphic activity may obscure information on the type and mechanism of metal addition to the shale. We used a combination of geochemical investigations at a variety of scales to discriminate between VMS-prospective and VMS-barren horizons. In addition, element signatures associated with hydrothermal plume fallout were identified and used and to determine relative direction to the palaeo-venting centre. Portable x-ray fluorescence (pXRF) analysers were used to identify and correlate prospective horizons within exploration drill cores. pXRF is a rapid and relatively inexpensive method of analysis that can deliver quantitative geochemical information at a cm-scale and help to identify intervals meriting further, more costly and time-consuming analyses. Subsequently, laser-ablation ICP-MS analysis of metal sulfides was used to constrain hydrothermal, hydrogenous and diagenetic end-member compositions, and to quantify element remobilization during post-burial alteration. These data were then used to refine the pXRF survey methodology and develop primary vectors toward potential concealed base metal deposits.

  18. Potential effect of matrix stiffness on the enrichment of tumor initiating cells under three-dimensional culture conditions.

    PubMed

    Liu, Chang; Liu, Yang; Xu, Xiao-xi; Wu, Hao; Xie, Hong-guo; Chen, Li; Lu, Ting; Yang, Li; Guo, Xin; Sun, Guang-wei; Wang, Wei; Ma, Xiao-jun; He, Xin

    2015-01-01

    Cancer stem cell (CSC) or tumor initiating cell (TIC) plays an important role in tumor progression and metastasis. Biophysical forces in tumor microenvironment have an important effect on tumor formation and development. In this study, the potential effect of matrix stiffness on the biological characteristics of human head and neck squamous cell carcinoma (HNSCC) TICs, especially the enrichment of HNSCC TICs, was investigated under three-dimensional (3D) culture conditions by means of alginate gel (ALG) beads with different matrix stiffnesses. ALG beads with soft (21 kPa), moderate (70 kPa) and hard (105 kPa) stiffness were generated by changing alginate concentration. It was found that significant HNSCC TIC enrichment was achieved in the ALG beads with moderate matrix stiffness (70 kPa). The gene expression of stemness markers Oct3/4 and Nanog, TIC markers CD44 and ABCG2 was enhanced in cells under this moderate (70 kPa) stiffness. HNSCC TIC proportion was also highly enriched under moderate matrix stiffness, accompanying with higher tumorigenicity, metastatic ability and drug resistance. And it was also found that the possible molecular mechanism underlying the regulated TIC properties by matrix stiffness under 3D culture conditions was significantly different from 2D culture condition. Therefore, the results achieved in this study indicated that 3D biophysical microenvironment had an important effect on TIC characteristics and alginate-based biomimetic scaffolds could be utilized as a proper platform to investigate the interaction between tumor cells and 3D microenvironment.

  19. A recursion relation for matrix elements of the quantum bouncer. Comment on "A quantum bouncing ball," by Julio Gea-Banacloche [Am. J. Phys. 67 (9), 776-782 (1999)

    NASA Astrophysics Data System (ADS)

    Goodmanson, David M.

    2000-09-01

    This paper describes a recursion relation for matrix elements of the quantum bouncer. The relation provides an exact expression for the normalization integral, and allows recursive calculation of matrix elements of the form , where z is the spatial coordinate and |m>,|n> are quantum bouncer eigenstates.

  20. The use of Ixaru's method in locating the poles of the S-matrix in strictly finite-range potentials

    SciTech Connect

    Vertse, Tamas; Lovas, R. G.; Racz, A.; Salamon, P.

    2012-09-26

    Energies of the S-matrix poles are calculated by solving the radial Schroedinger equation numerically by using Ixaru's CPM(2) method. The trajectories of the poles in the complex wave number plane are determined for two nuclear potentials that are zero beyond finite distances. These are the Woods-Saxon form with cutoff and the Salamon-Vertse potential, which goes to zero smoothly at a finite distance. Properties of the trajectories are analyzed for real and complex values of the depths of the corresponding potentials.

  1. Calculation of subsonic and supersonic steady and unsteady aerodynamic forces using velocity potential aerodynamic elements

    NASA Technical Reports Server (NTRS)

    Haviland, J. K.; Yoo, Y. S.

    1976-01-01

    Expressions for calculation of subsonic and supersonic, steady and unsteady aerodynamic forces are derived, using the concept of aerodynamic elements applied to the downwash velocity potential method. Aerodynamic elements can be of arbitrary out of plane polygon shape, although numerical calculations are restricted to rectangular elements, and to the steady state case in the supersonic examples. It is suggested that the use of conforming, in place of rectangular elements, would give better results. Agreement with results for subsonic oscillating T tails is fair, but results do not converge as the number of collocation points is increased. This appears to be due to the form of expression used in the calculations. The methods derived are expected to facilitate automated flutter analysis on the computer. In particular, the aerodynamic element concept is consistent with finite element methods already used for structural analysis. The method is universal for the complete Mach number range, and, finally, the calculations can be arranged so that they do not have to be repeated completely for every reduced frequency.

  2. Non-uniform FFT for the finite element computation of the micromagnetic scalar potential

    NASA Astrophysics Data System (ADS)

    Exl, L.; Schrefl, T.

    2014-08-01

    We present a quasi-linearly scaling, first order polynomial finite element method for the solution of the magnetostatic open boundary problem by splitting the magnetic scalar potential. The potential is determined by solving a Dirichlet problem and evaluation of the single layer potential by a fast approximation technique based on Fourier approximation of the kernel function. The latter approximation leads to a generalization of the well-known convolution theorem used in finite difference methods. We address it by a non-uniform FFT approach. Overall, our method scales O(M+N+Nlog N) for N nodes and M surface triangles. We confirm our approach by several numerical tests.

  3. Stochastic resonance with Woods-Saxon potential for rolling element bearing fault diagnosis

    NASA Astrophysics Data System (ADS)

    Lu, Siliang; He, Qingbo; Kong, Fanrang

    2014-04-01

    This paper proposes a weak signal detection strategy for rolling element bearing fault diagnosis by investigating a new mechanism to realize stochastic resonance (SR) based on the Woods-Saxon (WS) potential. The WS potential has the distinct structure with smooth potential bottom and steep potential wall, which guarantees a stable particle motion within the potential and avoids the unexpected noises for the SR system. In the Woods-Saxon SR (WSSR) model, the output signal-to-noise ratio (SNR) can be optimized just by tuning the WS potential's parameters, which delivers the most significant merit that the limitation of small parameter requirement of the classical bistable SR can be overcome, and thus a wide range of driving frequencies can be detected via the SR model. Furthermore, the proposed WSSR model is also insensitive to the noise, and can detect the weak signals with different noise levels. Additionally, the WS potential can be designed accurately due to its parameter independence, which implies that the proposed method can be matched to different input signals adaptively. With these properties, the proposed weak signal detection strategy is indicated to be beneficial to rolling element bearing fault diagnosis. Both the simulated and the practical bearing fault signals verify the effectiveness and efficiency of the proposed WSSR method in comparison with the traditional bistable SR method.

  4. Nuclear-structure dependence of O (. alpha. ) corrections to Fermi decays and the value of the Kobayashi-Maskawa matrix element V sub ud

    SciTech Connect

    Jaus, W.; Rasche, G. )

    1990-01-01

    We calculate nuclear-structure corrections to the {ital ft} values of the eight accurately measured superallowed {beta}{sup +} decays. The statistical fit for the average {ital ft} value is very good. The resulting new value for the matrix element of the Kobayashi-Maskawa (KM) matrix is {vert bar}{ital V}{sub {ital ud}}{vert bar}=0.9735(5). The error in {vert bar}{ital V}{sub {ital ud}}{vert bar} has thus been reduced by 50%. Combining this value for {vert bar}{ital V}{sub {ital ud}}{vert bar} with the presently accepted results from kaon-, hyperon-, and {ital B}-decay constraints, the unitarity of the KM matrix for three generations of quarks seems to be violated.

  5. Element analysis and calculation of the attenuation coefficients for gold, bronze and water matrixes using MCNP, WinXCom and experimental data

    NASA Astrophysics Data System (ADS)

    Esfandiari, M.; Shirmardi, S. P.; Medhat, M. E.

    2014-06-01

    In this study, element analysis and the mass attenuation coefficient for matrixes of gold, bronze and water with various impurities and the concentrations of heavy metals (Cu, Mn, Pb and Zn) are evaluated and calculated by the MCNP simulation code for photons emitted from Barium-133, Americium-241 and sources with energies between 1 and 100 keV. The MCNP data are compared with the experimental data and WinXCom code simulated results by Medhat. The results showed that the obtained results of bronze and gold matrix are in good agreement with the other methods for energies above 40 and 60 keV, respectively. However for water matrixes with various impurities, there is a good agreement between the three methods MCNP, WinXCom and the experimental one in low and high energies.

  6. The O(αs3) massive operator matrix elements of O(nf) for the structure function F2(x,Q2) and transversity

    PubMed Central

    Ablinger, J.; Blümlein, J.; Klein, S.; Schneider, C.; Wißbrock, F.

    2011-01-01

    The contributions ∝nf to the O(αs3) massive operator matrix elements describing the heavy flavor Wilson coefficients in the limit Q2≫m2 are computed for the structure function F2(x,Q2) and transversity for general values of the Mellin variable N. Here, for two matrix elements, Aqq,QPS(N) and Aqg,Q(N), the complete result is obtained. A first independent computation of the contributions to the 3-loop anomalous dimensions γqg(N), γqqPS(N), and γqqNS,(TR)(N) is given. In the computation advanced summation technologies for nested sums over products of hypergeometric terms with harmonic sums have been used. For intermediary results generalized harmonic sums occur, while the final results can be expressed by nested harmonic sums only. PMID:27293308

  7. Improved short-range correlations and 0{nu}{beta}{beta} nuclear matrix elements of {sup 76}Ge and {sup 82}Se

    SciTech Connect

    Kortelainen, Markus; Suhonen, Jouni

    2007-05-15

    We calculate the nuclear matrix elements of the neutrinoless double beta (0{nu}{beta}{beta}) decays of {sup 76}Ge and {sup 82}Se for the light neutrino exchange mechanism. The nuclear wave functions are obtained by using realistic two-body forces within the proton-neutron quasiparticle random-phase approximation (pnQRPA). We include the effects that come from the finite size of a nucleon, from the higher-order terms of nucleonic weak currents, and from the nucleon-nucleon short-range correlations. Most importantly, we improve on the presently available calculations by replacing the rudimentary Jastrow short-range correlations by the more advanced unitary correlation operator method (UCOM). The UCOM-corrected matrix elements turn out to be notably larger in magnitude than the Jastrow-corrected ones. This has drastic consequences for the detectability of 0{nu}{beta}{beta} decay in present and future double beta experiments.

  8. Potential health and environmental effects of trace elements and radionuclides from increased coal utilization.

    PubMed Central

    Van Hook, R I

    1979-01-01

    This report addresses the effects of coal-derived trace and radioactive elements. A summary of our current understanding of health and environmental effects of trace and radioactive elements released during coal mining, cleaning, combustion, and ash disposal is presented. Physical and biological transport phenomena which are important in determining organism exposure are also discussed. Biological concentration and transformation as well as synergistic and antagonistic actions among trace contaminants are discussed in terms of their importance in mobility, persistence, availability, and ultimate toxicity. The consequences of implementing the President's National Energy Plan are considered in terms of the impact of the NEP in 1985 and 2000 on the potential effects of trace and radioactive elements from the coal fuel cycle. Areas of needed research are identified in specific recommendations. PMID:540619

  9. On the use of finite difference matrix-vector products in Newton-Krylov solvers for implicit climate dynamics with spectral elements

    DOE PAGES

    Woodward, Carol S.; Gardner, David J.; Evans, Katherine J.

    2015-01-01

    Efficient solutions of global climate models require effectively handling disparate length and time scales. Implicit solution approaches allow time integration of the physical system with a step size governed by accuracy of the processes of interest rather than by stability of the fastest time scales present. Implicit approaches, however, require the solution of nonlinear systems within each time step. Usually, a Newton's method is applied to solve these systems. Each iteration of the Newton's method, in turn, requires the solution of a linear model of the nonlinear system. This model employs the Jacobian of the problem-defining nonlinear residual, but thismore » Jacobian can be costly to form. If a Krylov linear solver is used for the solution of the linear system, the action of the Jacobian matrix on a given vector is required. In the case of spectral element methods, the Jacobian is not calculated but only implemented through matrix-vector products. The matrix-vector multiply can also be approximated by a finite difference approximation which may introduce inaccuracy in the overall nonlinear solver. In this paper, we review the advantages and disadvantages of finite difference approximations of these matrix-vector products for climate dynamics within the spectral element shallow water dynamical core of the Community Atmosphere Model.« less

  10. On the Use of Finite Difference Matrix-Vector Products in Newton-Krylov Solvers for Implicit Climate Dynamics with Spectral Elements

    SciTech Connect

    Gardner, David; Woodward, Carol S.; Evans, Katherine J

    2015-01-01

    Efficient solution of global climate models requires effectively handling disparate length and time scales. Implicit solution approaches allow time integration of the physical system with a time step dictated by accuracy of the processes of interest rather than by stability governed by the fastest of the time scales present. Implicit approaches, however, require the solution of nonlinear systems within each time step. Usually, a Newton s method is applied for these systems. Each iteration of the Newton s method, in turn, requires the solution of a linear model of the nonlinear system. This model employs the Jacobian of the problem-defining nonlinear residual, but this Jacobian can be costly to form. If a Krylov linear solver is used for the solution of the linear system, the action of the Jacobian matrix on a given vector is required. In the case of spectral element methods, the Jacobian is not calculated but only implemented through matrix-vector products. The matrix-vector multiply can also be approximated by a finite-difference which may show a loss of accuracy in the overall nonlinear solver. In this paper, we review the advantages and disadvantages of finite-difference approximations of these matrix-vector products for climate dynamics within the spectral-element based shallow-water dynamical-core of the Community Atmosphere Model (CAM).

  11. On the use of finite difference matrix-vector products in Newton-Krylov solvers for implicit climate dynamics with spectral elements

    SciTech Connect

    Woodward, Carol S.; Gardner, David J.; Evans, Katherine J.

    2015-01-01

    Efficient solutions of global climate models require effectively handling disparate length and time scales. Implicit solution approaches allow time integration of the physical system with a step size governed by accuracy of the processes of interest rather than by stability of the fastest time scales present. Implicit approaches, however, require the solution of nonlinear systems within each time step. Usually, a Newton's method is applied to solve these systems. Each iteration of the Newton's method, in turn, requires the solution of a linear model of the nonlinear system. This model employs the Jacobian of the problem-defining nonlinear residual, but this Jacobian can be costly to form. If a Krylov linear solver is used for the solution of the linear system, the action of the Jacobian matrix on a given vector is required. In the case of spectral element methods, the Jacobian is not calculated but only implemented through matrix-vector products. The matrix-vector multiply can also be approximated by a finite difference approximation which may introduce inaccuracy in the overall nonlinear solver. In this paper, we review the advantages and disadvantages of finite difference approximations of these matrix-vector products for climate dynamics within the spectral element shallow water dynamical core of the Community Atmosphere Model.

  12. Matching NLO parton shower matrix element with exact phase space: case of W→ lν( γ) and γ ∗→ π + π -( γ)

    NASA Astrophysics Data System (ADS)

    Nanava, G.; Xu, Qingjun; WaŞ, Z.

    2010-12-01

    Monte Carlo is often used for simulation of QED effects in decay of intermediate particles and resonances. Momenta are generated in such a way that samples of events cover the whole bremsstrahlung phase space. With the help of selection cuts, experimental acceptance can then be taken into account. The program is based on an exact multi-photon phase space. A crude matrix element is obtained by iteration of a universal multidimensional kernel. It ensures exact distribution in the soft photon region. The algorithm is compatible with exclusive exponentiation. To evaluate the program's precision, it is necessary to control the kernel with the help of perturbative results. If available, the kernel is constructed from the exact first order matrix element. This ensures that all terms necessary for non-leading logarithms are taken into account. In the present paper we will focus on the W→ lν and γ ∗→ π + π - decays. The Born level cross sections for both processes approach zero in some points of the phase space. A process dependent compensating weight is constructed to incorporate the exact matrix element, but is recommended for use in tests only. In the hard photon region, where scalar QED is not expected to be reliable, the compensating weight for γ ∗ decay can be large. With respect to the total rate, the effect remains at the permille level. It is nonetheless of interest. The terms leading to the effect are analogous to some terms appearing in QCD. The present paper can be understood either as a contribution to discussion on how to match two collinear emission chains resulting from charged sources in a way compatible with the exact and complete phase space, exclusive exponentiation and the first order matrix element of QED (scalar QED), or as the practical study of predictions for accelerator experiments.

  13. A Measurement of the Top Quark Mass with the D0 Detector at s**(1/2) = 1.96-TeV using the Matrix Element Method

    SciTech Connect

    Kroeninger, Kevin Alexander; /Bonn U.

    2004-04-01

    Using a data set of 158 and 169 pb{sup -1} of D0 Run-II data in the electron and muon plus jets channel, respectively, the top quark mass has been measured using the Matrix Element Method. The method and its implementation are described. Its performance is studied in Monte Carlo using ensemble tests and the method is applied to the Moriond 2004 data set.

  14. Simplified Boson Realization of the soq Subalgebra of u_q(3) and Matrix Elements of so_q(3) Quadrupole Operators

    NASA Astrophysics Data System (ADS)

    Raychev, P. P.; Roussev, R. P.; Terziev, P. A.; Bonatsos, D.; Iudice, N. Lo

    1997-04-01

    A simplified boson realization of the soq subalgebra of u_q(3) is constructed. A simplified form of the corresponding so_q(3) basis states is obtained. The reduced matrix elements of a special second-rank tensor operator (quadrupole operator) are calculated in the so_q(3) basis (P. P. Raychev, R. P. Roussev, P. A. Terziev, D. Bonatsos and N. Lo Iudice, J. Phys. A (1996) in press).

  15. High-energy anomaly in the angle-resolved photoemission spectra of Nd(2-x)Ce(x)CuO₄: evidence for a matrix element effect.

    PubMed

    Rienks, E D L; Ärrälä, M; Lindroos, M; Roth, F; Tabis, W; Yu, G; Greven, M; Fink, J

    2014-09-26

    We use polarization-dependent angle-resolved photoemission spectroscopy (ARPES) to study the high-energy anomaly (HEA) in the dispersion of Nd(2-x)Ce(x)CuO₄, x=0.123. We find that at particular photon energies the anomalous, waterfall-like dispersion gives way to a broad, continuous band. This suggests that the HEA is a matrix element effect: it arises due to a suppression of the intensity of the broadened quasiparticle band in a narrow momentum range. We confirm this interpretation experimentally, by showing that the HEA appears when the matrix element is suppressed deliberately by changing the light polarization. Calculations of the matrix element using atomic wave functions and simulation of the ARPES intensity with one-step model calculations provide further evidence for this scenario. The possibility to detect the full quasiparticle dispersion further allows us to extract the high-energy self-energy function near the center and at the edge of the Brillouin zone. PMID:25302914

  16. High-Energy Anomaly in the Angle-Resolved Photoemission Spectra of Nd2-xCexCuO4: Evidence for a Matrix Element Effect

    NASA Astrophysics Data System (ADS)

    Rienks, E. D. L.; ńrrälä, M.; Lindroos, M.; Roth, F.; Tabis, W.; Yu, G.; Greven, M.; Fink, J.

    2014-09-01

    We use polarization-dependent angle-resolved photoemission spectroscopy (ARPES) to study the high-energy anomaly (HEA) in the dispersion of Nd2-xCexCuO4, x =0.123. We find that at particular photon energies the anomalous, waterfall-like dispersion gives way to a broad, continuous band. This suggests that the HEA is a matrix element effect: it arises due to a suppression of the intensity of the broadened quasiparticle band in a narrow momentum range. We confirm this interpretation experimentally, by showing that the HEA appears when the matrix element is suppressed deliberately by changing the light polarization. Calculations of the matrix element using atomic wave functions and simulation of the ARPES intensity with one-step model calculations provide further evidence for this scenario. The possibility to detect the full quasiparticle dispersion further allows us to extract the high-energy self-energy function near the center and at the edge of the Brillouin zone.

  17. Coupling finite and boundary element methods for two-dimensional potential problems

    NASA Technical Reports Server (NTRS)

    Krishnamurthy, T.; Raju, I. S.

    1992-01-01

    A finite element-boundary element (FE-BE) coupling method based on a weighted residual variational method is presented for potential problems, governed by either the Laplace or the Poisson equations. In this method, a portion of the domain of interest is modeled by finite elements (FE) and the remainder of the region by boundary elements (BE). Because the BE fundamental solutions are valid for infinite domains, a procedure that limits the effects of the BE fundamental solution to a small region adjacent to the FE region, called the transition region (TR), is developed. This procedure involves a judicious choice of functions called the transition (T) functions that have unit values on the BE-TR interface and zero values on the FE-TR interface. The present FE-BE coupling algorithm is shown to be independent of the extent of the transition region and the choice of the transition functions. Therefore, transition regions that extend to only one layer of elements between FE and BE regions and the use of simple linear transition functions work well.

  18. Distributions of the S-matrix poles in Woods-Saxon and cut-off Woods-Saxon potentials

    NASA Astrophysics Data System (ADS)

    Salamon, P.; Baran, Á.; Vertse, T.

    2016-08-01

    The positions of the l = 0S-matrix poles are calculated in generalized Woods-Saxon (GWS) potential and in cut-off generalized Woods-Saxon (CGWS) potential. The solutions of the radial equations are calculated numerically for the CGWS potential and analytically for GWS using the formalism of Gy. Bencze [1]. We calculate CGWS and GWS cases at small non-zero values of the diffuseness in order to approach the square well potential and to be able to separate effects of the radius parameter and the cut-off radius parameter. In the case of the GWS potential the wave functions are reflected at the nuclear radius therefore the distances of the resonant poles depend on the radius parameter of the potential. In CGWS potential the wave function can be reflected at larger distance where the potential is cut to zero and the derivative of the potential does not exist. The positions of most of the resonant poles do depend strongly on the cut-off radius of the potential, which is an unphysical parameter. Only the positions of the few narrow resonances in potentials with barrier are not sensitive to the cut-off distance. For the broad resonances the effect of the cut-off cannot be corrected by using a suggested analytical form of the first order perturbation correction.

  19. Potentially toxic elements in foodcrops: Triticum aestivum L., Zea mays L.

    NASA Astrophysics Data System (ADS)

    Bini, Claudio; Fontana, Silvia; Squizzato, Stefania; Minello, Fabiola; Fornasier, Flavio; Wahsha, Mohammad

    2013-04-01

    Soil is the basis of the ecosystems and of our system of food production. Crops can uptake heavy metals and potentially toxic elements from the soil and store them in the roots or translocate them to the aerial parts. Excessive content of these elements in edible parts can produce toxic effects and, through the food chain and food consumption, result in a potential hazard for human health. In this study soils and plants (spring wheat, Triticum aestivum L. and maize, Zea mays L.) from a tannery district in North-East Italy were analyzed to determine pedological characters, soil microbial indicators and the content of some major and micro-nutrients and potentially toxic elements (Al, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Ni, P, Pb, S, Zn, V). The soils of the area are moderately polluted; Cr is the most important inorganic contaminant, followed by Ni, Cu and V. Factor analysis evidenced that the contaminants are in part anthropogenic and in part geogenic. Major anthropogenic origin was detected for Cr, Ni (from industrial activities), Zn, Cu, Cd (from agriculture practices). Biological Absorption Coefficient (BAC) from soil to plant roots and Translocation factor (TF) within the plant were calculated; major nutrients (K, P, S) and some micronutrients (Cu, Zn, Mg, Mn) are easily absorbed and translocated, whilst other nutrients (Ca, Fe) and potentially toxic elements or micronutrients (Al, Cd, Cr, Ni, Pb, V) are not accumulated in the seeds of the two considered species. However, the two edible species proved differently able to absorb and translocate elements, and this suggests to consider separately every species as potential PHEs transporter to the food chain and to humans. Cr concentrations in seeds and other aerial parts (stem and leaves) of the examined plants are higher than the values found for the same species and for other cereals grown on unpolluted soils. Comparing the Cr levels in edible parts with recommended dietary intake, besides other possible Cr sources

  20. Simulation of 2D Brain's Potential Distribution Based on Two Electrodes ECVT Using Finite Element Method

    NASA Astrophysics Data System (ADS)

    Sirait, S. H.; Edison, R. E.; Baidillah, M. R.; Taruno, W. P.; Haryanto, F.

    2016-08-01

    The aim of this study is to simulate the potential distribution of 2D brain geometry based on two electrodes ECVT. ECVT (electrical capacitance tomography) is a tomography modality which produces dielectric distribution image of a subject from several capacitance electrodes measurements. This study begins by producing the geometry of 2D brain based on MRI image and then setting the boundary conditions on the boundaries of the geometry. The values of boundary conditions follow the potential values used in two electrodes brain ECVT, and for this reason the first boundary is set to 20 volt and 2.5 MHz signal and another boundary is set to ground. Poisson equation is implemented as the governing equation in the 2D brain geometry and finite element method is used to solve the equation. Simulated Hodgkin-Huxley action potential is applied as disturbance potential in the geometry. We divide this study into two which comprises simulation without disturbance potential and simulation with disturbance potential. From this study, each of time dependent potential distributions from non-disturbance and disturbance potential of the 2D brain geometry has been generated.

  1. Arabidopsis and the Genetic Potential for the Phytoremediation of Toxic Elemental and Organic Pollutants

    PubMed Central

    Cobbett, Christopher S.; Meagher, Richard B.

    2002-01-01

    In a process called phytoremediation, plants can be used to extract, detoxify, and/or sequester toxic pollutants from soil, water, and air. Phytoremediation may become an essential tool in cleaning the environment and reducing human and animal exposure to potential carcinogens and other toxins. Arabidopsis has provided useful information about the genetic, physiological, and biochemical mechanisms behind phytoremediation, and it is an excellent model genetic organism to test foreign gene expression. This review focuses on Arabidopsis studies concerning: 1) the remediation of elemental pollutants; 2) the remediation of organic pollutants; and 3) the phytoremediation genome. Elemental pollutants include heavy metals and metalloids (e.g., mercury, lead, cadmium, arsenic) that are immutable. The general goal of phytoremediation is to extract, detoxify, and hyperaccumulate elemental pollutants in above-ground plant tissues for later harvest. A few dozen Arabidopsis genes and proteins that play direct roles in the remediation of elemental pollutants are discussed. Organic pollutants include toxic chemicals such as benzene, benzo(a)pyrene, polychlorinated biphenyls, trichloroethylene, trinitrotoluene, and dichlorodiphenyltrichloroethane. Phytoremediation of organic pollutants is focused on their complete mineralization to harmless products, however, less is known about the potential of plants to act on complex organic chemicals. A preliminary survey of the Arabidopsis genome suggests that as many as 700 genes encode proteins that have the capacity to act directly on environmental pollutants or could be modified to do so. The potential of the phytoremediation proteome to be used to reduce human exposure to toxic pollutants appears to be enormous and untapped. PMID:22303204

  2. Non-negative matrix factorization for the near real-time interpretation of absorption effects in elemental distribution images acquired by X-ray fluorescence imaging.

    PubMed

    Alfeld, Matthias; Wahabzada, Mirwaes; Bauckhage, Christian; Kersting, Kristian; Wellenreuther, Gerd; Barriobero-Vila, Pere; Requena, Guillermo; Boesenberg, Ulrike; Falkenberg, Gerald

    2016-03-01

    Elemental distribution images acquired by imaging X-ray fluorescence analysis can contain high degrees of redundancy and weakly discernible correlations. In this article near real-time non-negative matrix factorization (NMF) is described for the analysis of a number of data sets acquired from samples of a bi-modal α+β Ti-6Al-6V-2Sn alloy. NMF was used for the first time to reveal absorption artefacts in the elemental distribution images of the samples, where two phases of the alloy, namely α and β, were in superposition. The findings and interpretation of the NMF results were confirmed by Monte Carlo simulation of the layered alloy system. Furthermore, it is shown how the simultaneous factorization of several stacks of elemental distribution images provides uniform basis vectors and consequently simplifies the interpretation of the representation. PMID:26917147

  3. Measurement of the top quark mass with the matrix element method in the semileptonic decay channel at D0

    SciTech Connect

    Haefner, Petra

    2008-07-31

    The top quark plays a special role in the Standard Model of Particle Physics. With its enormous mass of about 170 GeV it is as heavy as a gold atom and is the only quark with a mass near the electroweak scale. Together with theW boson mass, the top quark mass allows indirect constraints on the mass of the hypothetical Higgs boson, which might hold the clue to the origin of mass. Top pair production with a semileptonic decay t $\\bar{t}$ →W±W b$\\bar{b}$ →q $\\bar{t}$lnb$\\bar{b}$ is the ”golden channel” for mass measurements, due to a large branching fraction and a relatively low background contamination compared to other decay channels. Top mass measurements based on this decay, performed with the matrix element method, have always been among the single best measurements in the world. In 2007, the top mass world average broke the 1% level of precision. Its measurement is no longer dominated by statistical but instead by systematic uncertainties. The reduction of systematic uncertainties has therefore become a key issue for further progress. This thesis introduces two new developments in the treatment of b jets. The first improvement is an optimization in the way b identification information is used. It leads to an enhanced separation between signal and background processes and reduces the statistical uncertainty by about 16%. The second improvement determines differences in the detector response and thus the energy scales of light jets and b jets. Thereby, it addresses the major source of systematic uncertainty in the latest top mass measurements. The method was validated on Monte Carlo events at the generator level, calibrated with fully simulated events, including detector simulation, and applied to D0 Run II data corresponding to 1 fb-1 of integrated luminosity. Possible sources of systematic uncertainties were studied. The top mass is measured to be: mt = (169.2±3.5(stat.)±1.0(syst.)) GeV . The

  4. Potentially hazardous elements in coal: Modes of occurrence and summary of concentration data for coal components

    USGS Publications Warehouse

    Kolker, A.; Finkelman, R.B.

    1998-01-01

    Mode-of-occurrence data are summarized for 13 potentially hazardous elements (Be, Cr, Mn, Co, Ni, As, Se, Cd, Sb, Hg, Pb, Th, U) in coal. Recent work has refined mode-of-occurrence data for Ni, Cr, and As, as compared to previous summaries. For Cr, dominant modes of occurrence include the clay mineral illite, an amorphous CrO(OH) phase, and Cr-bearing spinels. Nickel is present in Fe-sulfides (pyrite and marcasite) and is also organically bound. Arsenic-bearing pyrite may be the dominant host of As in bituminous coals. Concentration data for the 13 HAPs, obtained primarily by quantitative microanalysis techniques, are compiled for mineral and organic portions of coal. HAPs element concentrations are greatest in Fe-sulfides, and include maxima of 2,300 ppm (Co), 4,500 ppm (Ni), 4.9wt.% (As), 2,000 ppm (Se), 171 ppm (Hg), and 5,500 ppm (Pb). Trace-element microanalysis is a significant refinement over bulk methods, and shows that there is considerable trace-element variation on a fine scale for a given coal, and from one coal to another. ?? 1998 OPA (Overseas Publishers Association) N.V. Published by license under the Gordon and Breach Science Publishers imprint.

  5. The Kronig-Penney model extended to arbitrary potentials via numerical matrix mechanics

    NASA Astrophysics Data System (ADS)

    Pavelich, R. L.; Marsiglio, F.

    2015-09-01

    The Kronig-Penney model is a common starting point for studying the quantum mechanics of electrons in a confining periodic potential. This model uses a square-well potential; the energies and eigenstates can be obtained analytically for a single well, and then Bloch's theorem allows one to extend these solutions to the periodically repeating potential. In this work, we describe how to obtain simple numerical solutions for the eigenvalues and eigenstates for any confining one-dimensional potential within a unit cell and then extend this procedure, with virtually no extra effort, to the case of arbitrary periodically repeating potentials. In this way, one can study the band structure effects that arise from differently shaped potentials. One of these effects is the electron-hole mass asymmetry; more realistic unit cell potentials generally give rise to higher electron-hole mass asymmetries.

  6. LMAN1 (ERGIC-53) is a potential carrier protein for matrix metalloproteinase-9 glycoprotein secretion

    PubMed Central

    Duellman, Tyler; Burnett, John; Shin, Alice; Yang, Jay

    2015-01-01

    Matrix metalloproteinase-9 (MMP-9) is a secreted glycoprotein with a major role in shaping the extra-cellular matrix and a detailed understanding of the secretory mechanism could help identify methods to correct diseases resulting from dysregulation of secretion. MMP-9 appears to follow a canonical secretory pathway through a quality control cycle in the endoplasmic reticulum (ER) before transport of the properly folded protein to the Golgi apparatus and beyond for secretion. Through a complementation assay, we determined that LMAN1, a well-studied lectin-carrier protein, interacts with a secretion-competent N-glycosylated MMP-9 in the ER while N-glycosylation-deficient secretion-compromised MMP-9 does not. In contrast, co-immunoprecipitation demonstrated protein interaction between LMAN1 and secretion-compromised N-glycosylation-deficient MMP-9. MMP-9 secretion was reduced in the LMAN1 knockout cell line compared to control cells confirming the functional role of LMAN1. These observations support the role of LMAN1 as a lectin-carrier protein mediating efficient MMP-9 secretion. PMID:26150355

  7. Detection of Matrix Elements and Trace Impurities in Cu(In, Ga)Se2 Photovoltaic Absorbers Using Surface Analytical Techniques.

    PubMed

    Kim, Min Jung; Lee, Jihye; Kim, Seon Hee; Kim, Haidong; Lee, Kang-Bong; Lee, Yeonhee

    2015-10-01

    Chalcopyrite Cu(In, Ga)Se2 (CIGS) thin films are well known as the next-generation solar cell materials notable for their high absorption coefficient for solar radiation, suitable band gap, and ability for deposition on flexible substrate materials, allowing the production of highly flexible and lightweight solar panels. To improve solar cell performances, a quantitative and depth-resolved elemental analysis of photovoltaic thin films is much needed. In this study, Cu(In, Ga)Se2 thin films were prepared on molybdenum back contacts deposited on soda-lime glass substrates via three-stage evaporation. Surface analyses via AES and SIMS were used to characterize the CIGS thin films and compare their depth profiles. We determined the average concentration of the matrix elements, Cu, In, Ga, and Se, using ICP-AES, XRF, and EPMA. We also obtained depth profiling results using TOF-SIMS, magnetic sector SIMS and AES, and APT, a sub-nanometer resolution characterization technique that enables three-dimensional elemental mapping. The SIMS technique, with its high detection limit and ability to obtain the profiles of elements in parallel, is a powerful tool for monitoring trace elements in CIGS thin films. To identify impurities in a CIGS layer, the distribution of trace elements was also observed according to depth by SIMS and APT.

  8. Long-term analysis of elemental content in airborne particulate matter by PIXE and positive matrix factorization: Annual trends and seasonal variability during 2003 and 2008

    NASA Astrophysics Data System (ADS)

    Pražnikar, Jure; Cepak, Franka; Žibert, Janez

    2014-09-01

    In the presented study a comprehensive statistical analysis of the chemical composition of atmospheric particulate matter was carried out. The data were collected from April 2003 to August 2008 with a 7-day time resolution in the Northern Adriatic Port of Koper and analyzed by the Proton Induced X-ray method (PIXE). The Positive Matrix Factorization (PMF) analysis of fifteen chemical elements identified six source factors, three natural-regional sources and three local-anthropogenic sources. Heavy machinery, industry and iron ore factor were marked as anthropogenic sources. Heavy machinery source was represented by the elements V, Ni and Cu. The elements Fe and Mn are attributed to the Iron ore source and were explained by the proximity of the bulk-cargo warehouse and the intense handling of iron ore in Port of Koper. The heavy industry source represented by Pb and Zn was the only anthropogenic factor, which shows clear seasonal pattern. In contrast to the local-anthropogenic source factors, natural and regional source factors show significant negative trend. The reduction of the crustal elements Ca, Ti and Sr, joined in a soil source, and sulfur-biomass source, represented by elements K and S, have been attributed to more intense precipitation and to the negative trend of the North Atlantic Oscillation (NAO) index. The negative trend of the Cl and Br elements was in line with the negative trend of the wind speed above the sea surface and the significant sea-wave height.

  9. Detection of Matrix Elements and Trace Impurities in Cu(In, Ga)Se2 Photovoltaic Absorbers Using Surface Analytical Techniques.

    PubMed

    Kim, Min Jung; Lee, Jihye; Kim, Seon Hee; Kim, Haidong; Lee, Kang-Bong; Lee, Yeonhee

    2015-10-01

    Chalcopyrite Cu(In, Ga)Se2 (CIGS) thin films are well known as the next-generation solar cell materials notable for their high absorption coefficient for solar radiation, suitable band gap, and ability for deposition on flexible substrate materials, allowing the production of highly flexible and lightweight solar panels. To improve solar cell performances, a quantitative and depth-resolved elemental analysis of photovoltaic thin films is much needed. In this study, Cu(In, Ga)Se2 thin films were prepared on molybdenum back contacts deposited on soda-lime glass substrates via three-stage evaporation. Surface analyses via AES and SIMS were used to characterize the CIGS thin films and compare their depth profiles. We determined the average concentration of the matrix elements, Cu, In, Ga, and Se, using ICP-AES, XRF, and EPMA. We also obtained depth profiling results using TOF-SIMS, magnetic sector SIMS and AES, and APT, a sub-nanometer resolution characterization technique that enables three-dimensional elemental mapping. The SIMS technique, with its high detection limit and ability to obtain the profiles of elements in parallel, is a powerful tool for monitoring trace elements in CIGS thin films. To identify impurities in a CIGS layer, the distribution of trace elements was also observed according to depth by SIMS and APT. PMID:26726401

  10. Study of road dust magnetic phases as the main carrier of potentially harmful trace elements.

    PubMed

    Bourliva, Anna; Papadopoulou, Lambrini; Aidona, Elina

    2016-05-15

    Mineralogical and morphological characteristics and heavy metal content of different fractions (bulk, non-magnetic fraction-NMF and magnetic fraction-MF) of road dusts from the city of Thessaloniki (Northern Greece) were investigated. Main emphasis was given on the magnetic phases extracted from these dusts. High magnetic susceptibility values were presented, whereas the MFs content of road dust samples ranged in 2.2-14.7 wt.%. Thermomagnetic analyses indicated that the dominating magnetic carrier in all road dust samples was magnetite, while the presence of hematite and iron sulphides in the investigated samples cannot be excluded. SEM/EDX analyses identified two groups of ferrimagnetic particles: spherules with various surface morphologies and textures and angular/aggregate particles with elevated heavy metal contents, especially Cr. The road dusts (bulk samples) were dominated by calcium, while the mean concentrations of trace elements decreased in the order Zn > Mn > Cu > Pb > Cr > Ni > V > Sn > As > Sb > Co > Mo > W > Cd. MFs exhibited significantly higher concentrations of trace elements compared to NMFs indicating that these potentially harmful elements (PHEs) are preferentially enriched in the MFs and highly associated with the ferrimagnetic particles. Hazard Index (HI) obtained for both adults and children through exposure to bulk dust samples were lower or close to the safe level (=1). On the contrary, the HIs for the magnetic phases indicated that both children and adults are experiencing potential health risk since HI for Cr was significantly higher than safe level. Cancer risk due to road dust exposure is low.

  11. Potentially-toxic and essential elements profile of AH1N1 patients in Mexico City

    PubMed Central

    Moya, Mireya; Bautista, Edgar G.; Velázquez-González, Antonio; Vázquez-Gutiérrez, Felipe; Tzintzun, Guadalupe; García-Arreola, María Elena; Castillejos, Manuel; Hernández, Andrés

    2013-01-01

    During spring of 2009, a new influenza virus AH1N1 spread in the world causing acute respiratory illness and death, resulting in the first influenza pandemic since 1968. Blood levels of potentially-toxic and essential elements of 40 pneumonia and confirmed AH1N1 were evaluated against two different groups of controls, both not infected with the pandemic strain. Significant concentrations of potentially-toxic elements (lead, mercury, cadmium, chromium, arsenic) along with deficiency of selenium or increased Zn/Cu ratios characterized AH1N1 cases under study when evaluated versus controlled cases. Deficiency of selenium is progressively observed from controls I (influenza like illness) through controls II (pneumonia) and finally pneumonia -AH1N1 infected patients. Cases with blood Se levels greater than the recommended for an optimal cut-off to activate glutathione peroxidase (12.5 μg/dL) recovered from illness and survived. Evaluation of this essential element in critical pneumonia patients at the National Institutes is under evaluation as a clinical trial. PMID:23422930

  12. Preliminary Assessment of Health Risks of Potentially Toxic Elements in Settled Dust over Beijing Urban Area

    PubMed Central

    Wan, Dejun; Zhan, Changlin; Yang, Guanglin; Liu, Xingqi; Yang, Jinsong

    2016-01-01

    To examine levels, health risks, sources, and spatial distributions of potentially toxic elements in settled dust over Beijing urban area, 62 samples were collected mostly from residential building outdoor surfaces, and their <63 μm fractions were measured for 12 potentially toxic elements. The results show that V, Cr, Mn, Co, Ni, and Ba in dust are from predominantly natural sources, whereas Cu, Zn, As, Cd, Sb, and Pb mostly originate from anthropogenic sources. Exposure to these elements in dust has significant non-cancer risks to children but insignificant to adults. Cancer risks of Cr, Co, Ni, As, and Cd via inhalation and dermal contact are below the threshold of 10−6–10−4 but As via dust ingestion shows a tolerable risk. The non-cancer risks to children are contributed mainly (75%) by As, Pb, and Sb, and dominantly (92%) via dust ingestion, with relatively higher risks mainly occurring in the eastern and northeastern Beijing urban areas. Although Cd, Zn, and Cu in dust are heavily affected by anthropogenic sources, their health risks are insignificant. Source appointments suggest that coal burning emissions, the dominant source of As, are likely the largest contributors to the health risk, and traffic-related and industrial emissions are also important because they contribute most of the Pb and Sb in dust. PMID:27187427

  13. Coupling Finite Element and Meshless Local Petrov-Galerkin Methods for Two-Dimensional Potential Problems

    NASA Technical Reports Server (NTRS)

    Chen, T.; Raju, I. S.

    2002-01-01

    A coupled finite element (FE) method and meshless local Petrov-Galerkin (MLPG) method for analyzing two-dimensional potential problems is presented in this paper. The analysis domain is subdivided into two regions, a finite element (FE) region and a meshless (MM) region. A single weighted residual form is written for the entire domain. Independent trial and test functions are assumed in the FE and MM regions. A transition region is created between the two regions. The transition region blends the trial and test functions of the FE and MM regions. The trial function blending is achieved using a technique similar to the 'Coons patch' method that is widely used in computer-aided geometric design. The test function blending is achieved by using either FE or MM test functions on the nodes in the transition element. The technique was evaluated by applying the coupled method to two potential problems governed by the Poisson equation. The coupled method passed all the patch test problems and gave accurate solutions for the problems studied.

  14. The use of cation exchange matrix separation coupled with ICP-MS to directly determine platinum group element (PGE) and other trace element emissions from passenger cars equipped with diesel particulate filters (DPF).

    PubMed

    Cairns, Warren R L; De Boni, Antonella; Cozzi, Giulio; Asti, Massimo; Borla, Edoardo Merlone; Parussa, Flavio; Moretto, Ezio; Cescon, Paolo; Boutron, Claude; Gabrieli, Jacopo; Barbante, Carlo

    2011-03-01

    Inductively coupled plasma-mass spectrometry coupled with cation exchange matrix separation has been optimised for the direct determination of platinum group element (PGE) and trace element emissions from a diesel engine car. After matrix separation method detection limits of 1.6 ng g(-1) for Pd, 0.4 ng g(-1) for Rh and 4.3 ng g(-1) for Pt were achieved, the method was validated against the certified reference material BCR 723, urban road dust. The test vehicle was fitted with new and aged catalytic converters with and without diesel particulate filters (DPF). Samples were collected after three consecutive New European Driving Cycle (NEDC) of the particulate and "soluble" phases using a home-made sampler optimised for trace element analysis. Emission factors for the PGEs ranged from 0.021 ng km(-1) for Rh to 70.5 ng km(-1) for Pt; when a DPF was fitted, the emission factors for the PGEs actually used in the catalysts dropped by up to 97% (for Pt). Trace element emission factors were found to drop by a maximum of 92% for Ni to a minimum of 18% for Y when a DPF was fitted; a new DPF was also found to cause a reduction of up to 86% in the emission of particulate matter.

  15. Feature extraction and recognition for rolling element bearing fault utilizing short-time Fourier transform and non-negative matrix factorization

    NASA Astrophysics Data System (ADS)

    Gao, Huizhong; Liang, Lin; Chen, Xiaoguang; Xu, Guanghua

    2015-01-01

    Due to the non-stationary characteristics of vibration signals acquired from rolling element bearing fault, the time-frequency analysis is often applied to describe the local information of these unstable signals smartly. However, it is difficult to classify the high dimensional feature matrix directly because of too large dimensions for many classifiers. This paper combines the concepts of time-frequency distribution(TFD) with non-negative matrix factorization(NMF), and proposes a novel TFD matrix factorization method to enhance representation and identification of bearing fault. Throughout this method, the TFD of a vibration signal is firstly accomplished to describe the localized faults with short-time Fourier transform(STFT). Then, the supervised NMF mapping is adopted to extract the fault features from TFD. Meanwhile, the fault samples can be clustered and recognized automatically by using the clustering property of NMF. The proposed method takes advantages of the NMF in the parts-based representation and the adaptive clustering. The localized fault features of interest can be extracted as well. To evaluate the performance of the proposed method, the 9 kinds of the bearing fault on a test bench is performed. The proposed method can effectively identify the fault severity and different fault types. Moreover, in comparison with the artificial neural network(ANN), NMF yields 99.3% mean accuracy which is much superior to ANN. This research presents a simple and practical resolution for the fault diagnosis problem of rolling element bearing in high dimensional feature space.

  16. Leaves of Phragmites australis as potential atmospheric biomonitors of Platinum Group Elements.

    PubMed

    Bonanno, Giuseppe; Pavone, Pietro

    2015-04-01

    The increasing emissions of Platinum Group Elements (PGEs), namely Pt, Pd and Rh, may pose a significant risk to ecosystem processes and human health. A periodic assessment of PGEs distribution in the environment is thus of the utmost importance for the implementation of timely measures of mitigation. Although several studies have quantified PGEs in different life forms such as mammals, birds, fish, crustaceans, algae, mosses and even human beings, data about vascular plants need further surveys. This study aimed to test the suitability of the grass Phragmites australis (common reed) as a biomonitor of PGEs atmospheric pollution. The results showed that Pd and Pt concentrations in leaves are significantly higher in urban areas. In particular, Pd showed the highest range of values in line with current studies that consider palladium as the main element of traffic-related pollution. Overall, the leaves of Phragmites australis reflected the different gradient of PGEs emissions, and may thus be considered as potential biomonitors of atmospheric pollution.

  17. EFFECT OF COULOMB COLLISIONS ON THE GRAVITATIONAL SETTLING OF LOW AND HIGH FIRST IONIZATION POTENTIAL ELEMENTS

    SciTech Connect

    Bo, Iselin M. Th.; Esser, Ruth; Lie-Svendsen, Oystein E-mail: ruth.esser@uit.no

    2013-05-20

    We model the effect of gravitational settling in the upper chromosphere on O, Fe, Si, and Ne, studying whether Coulomb collisions between ionized low First Ionization Potential (FIP) elements and protons is sufficient to cause abundance enhancements relative to oxygen. We find that low-FIP abundance enhancements comparable to observed values can be obtained provided the hydrogen ionization degree lies in the approximate range 10%-30%, which agrees with chromospheric models. Lower or higher hydrogen ionization causes the FIP-effect to become smaller or absent (depletion of all heavy elements). Iron must be almost fully ionized in order to become enriched relative to high-FIP elements, and this requires a high iron photoionization rate. The time scale necessary to produce the enrichment increases rapidly with increasing H ionization. For iron in a background from a semiempirical chromospheric model, with an H ion fraction of the order of 30%-40% in the upper chromosphere, 1-2 hr of settling is required to produce enhancements comparable to observations. The absolute abundance (relative to H), which monotonically decreases with time during settling, has by that time decreased by less than 50% in the same altitude region. With the same background conditions, the silicon abundance is more strongly enhanced by the settling than the iron abundance. The high-FIP element neon is depleted, relative to O and low-FIP elements, in the same background and altitude region where iron is enhanced, typically by 50% or more relative to O after 1-2 hr of settling.

  18. Extracellular matrix macromolecules: potential tools and targets in cancer gene therapy.

    PubMed

    Sainio, Annele; Järveläinen, Hannu

    2014-01-01

    Tumour cells create their own microenvironment where they closely interact with a variety of soluble and non-soluble molecules, different cells and numerous other components within the extracellular matrix (ECM). Interaction between tumour cells and the ECM is bidirectional leading to either progression or inhibition of tumourigenesis. Therefore, development of novel therapies targeted primarily to tumour microenvironment (TME) is highly rational. Here, we give a short overview of different macromolecules of the ECM and introduce mechanisms whereby they contribute to tumourigenesis within the TME. Furthermore, we present examples of individual ECM macromolecules as regulators of cell behaviour during tumourigenesis. Finally, we focus on novel strategies of using ECM macromolecules as tools or targets in cancer gene therapy in the future.

  19. Matrix Metalloproteinases as Potential Targets in the Venous Dilation Associated with Varicose Veins

    PubMed Central

    Kucukguven, Arda; Khalil, Raouf A.

    2013-01-01

    Varicose veins (VVs) are a common venous disease of the lower extremity characterized by incompetent valves, venous reflux, and dilated and tortuous veins. If untreated, VVs could lead to venous thrombosis, thrombophlebitis and chronic venous leg ulcers. Various genetic, hormonal and environmental factors may lead to structural changes in the vein valves and make them incompetent, leading to venous reflux, increased venous pressure and vein wall dilation. Prolonged increases in venous pressure and vein wall tension are thought to increase the expression/activity of matrix metalloproteinases (MMPs). Members of the MMPs family include collagenases, gelatinases, stromelysins, matrilysins, membrane-type MMPs and others. MMPs are known to degrade various components of the extracellular matrix (ECM). MMPs may also affect the endothelium and vascular smooth muscle, causing changes in the vein relaxation and contraction mechanisms. ECs injury also triggers leukocyte infiltration, activation and inflammation, which lead to further vein wall damage. The vein wall dilation and valve dysfunction, and the MMP activation and superimposed inflammation and fibrosis would lead to progressive venous dilation and VVs formation. Surgical ablation is an effective treatment for VVs, but may be associated with high recurrence rate, and other less invasive approaches that target the cause of the disease are needed. MMP inhibitors including endogenous tissue inhibitors (TIMPs) and pharmacological inhibitors such as zinc chelators, doxycycline, batimastat and marimastat, have been used as diagnostic and therapeutic tools in cancer, autoimmune and cardiovascular disease. However, MMP inhibitors may have side effects especially on the musculoskeletal system. With the advent of new genetic and pharmacological tools, specific MMP inhibitors with fewer undesirable effects could be useful to retard the progression and prevent the recurrence of VVs. PMID:23316963

  20. Matrix metalloproteinases as potential targets in the venous dilation associated with varicose veins.

    PubMed

    Kucukguven, Arda; Khalil, Raouf A

    2013-03-01

    Varicose veins (VVs) are a common venous disease of the lower extremity characterized by incompetent valves, venous reflux, and dilated and tortuous veins. If untreated, VVs could lead to venous thrombosis, thrombophlebitis and chronic venous leg ulcers. Various genetic, hormonal and environmental factors may lead to structural changes in the vein valves and make them incompetent, leading to venous reflux, increased venous pressure and vein wall dilation. Prolonged increases in venous pressure and vein wall tension are thought to increase the expression/activity of matrix metalloproteinases (MMPs). Members of the MMPs family include collagenases, gelatinases, stromelysins, matrilysins, membrane- type MMPs and others. MMPs are known to degrade various components of the extracellular matrix (ECM). MMPs may also affect the endothelium and vascular smooth muscle, causing changes in the vein relaxation and contraction mechanisms. Endothelial cell injury also triggers leukocyte infiltration, activation and inflammation, which lead to further vein wall damage. The vein wall dilation and valve dysfunction, and the MMP activation and superimposed inflammation and fibrosis would lead to progressive venous dilation and VVs formation. Surgical ablation is an effective treatment for VVs, but may be associated with high recurrence rate, and other less invasive approaches that target the cause of the disease are needed. MMP inhibitors including endogenous tissue inhibitors (TIMPs) and pharmacological inhibitors such as zinc chelators, doxycycline, batimastat and marimastat, have been used as diagnostic and therapeutic tools in cancer, autoimmune and cardiovascular disease. However, MMP inhibitors may have side effects especially on the musculoskeletal system. With the advent of new genetic and pharmacological tools, specific MMP inhibitors with fewer undesirable effects could be useful to retard the progression and prevent the recurrence of VVs.

  1. Minor and potentially toxic trace elements in milk and blood serum of dairy donkeys.

    PubMed

    Fantuz, F; Ferraro, S; Todini, L; Piloni, R; Mariani, P; Malissiova, E; Salimei, E

    2015-08-01

    Cs. In the current experimental conditions, in agreement with the low levels in drinking water and feedstuff, donkey milk concentration of potentially toxic elements was very low and did not raise health concerns for human consumption.

  2. Processing of single-walled carbon-nanotube metal matrix composites and a finite element model for the process

    NASA Astrophysics Data System (ADS)

    Wilson, Kenneth

    In the present investigation, single-walled carbon nanotube (SWCNT or SWNT) reinforced titanium (Ti) matrix composites have been produced by powder metallurgy (PM) and induction heating methods. It has been found that a nickel coating and a fast processing time associated with the induction heating method enables carbon nanotubes to survive the high-temperature (above 1950 K) processing conditions. The result has been a Ti-SWCNT metal-matrix composite (MMC) which is three times stronger and harder than Ti alone, a consequence that has never been accomplished before. This is a promising new development in the application of SWCNT technology to materials science. A mathematical model is given to support the experimental findings.

  3. Tests on the extracted current density of negative hydrogen ions from a single element of the matrix source

    SciTech Connect

    Lishev, St.; Yordanov, D. Shivarova, A.

    2015-04-08

    Concepts for the extraction of volume-produced negative hydrogen ions from a rf matrix source (a matrix of small-radius discharges with a planar-coil inductive driving) are presented and discussed based on experimental results for the current densities of the extracted ions and the co-extracted electrons. The experiment has been carried out in a single discharge of the source: a rf discharge with a radius of 2.25 cm inductively driven by a 3.5-turn planar coil. The length of the discharge tube, the area of the reference electrode inserted in the discharge volume, the discharge modes, the magnetic filter and its position along the discharge length, the position of the permanent magnets for the separation of the co-extracted electrons from the extracted ions in the extraction device and the bias applied to its first electrode are considered as factors influencing the extracted currents of negative ions.

  4. Phytoextraction of potentially toxic elements by Indian mustard, rapeseed, and sunflower from a contaminated riparian soil.

    PubMed

    Shaheen, Sabry M; Rinklebe, Jörg

    2015-12-01

    The objective of this study was to quantify the phytoextraction of the potentially toxic elements Al, As, Cd, Co, Cr, Cu, Mo, Ni, Pb, Se, V, and Zn by Indian mustard, rapeseed, and sunflower from a contaminated riparian soil. To achieve this goal, a greenhouse pot experiment was established using a highly contaminated grassland soil collected at the Wupper River (Germany). The impact of ethylene-diamine-tetra-acetic acid (EDTA), humate (HK), and phosphate potassium (PK) on the mobility and uptake of the elements by rapeseed also was investigated. Indian mustard showed the highest efficiency for phytoextraction of Al, Cr, Mo, Se, and V; sunflower for Cd, Ni, Pb, and Zn, and rapeseed for Cu. The bioconcentration ratios were higher than 1 for the elements (except As and Cu), indicating the suitability of the studied plants for phytoextraction. Application of EDTA to the soil increased significantly the solubility of Cd, Co, Cr, Ni, and Pb and decreased the solubility of Al, As, Se, V, and Mo. Humate potassium decreased significantly the concentrations of Al and As in rapeseed but increased the concentrations of Cu, Se, and Zn. We may conclude that HK can be used for immobilization of Al and As, while it can be used for enhancing the phytoextraction of Cu, Se, and Zn by rapeseed. Phosphate potassium immobilized Al, Cd, Pb, and Zn, but enhanced phytoextraction of As, Cr, Mo, and Se by rapeseed.

  5. The structure of the human peripherin gene (PRPH) and identification of potential regulatory elements

    SciTech Connect

    Foley, J.; Ley, C.A.; Parysek, L.M.

    1994-07-15

    The authors determined the complete nucleotide sequence of the coding region of the human peripherin gene (PRPH), as well as 742 bp 5{prime} to the cap site and 584 bp 3{prime} to the stop codon, and compared its structure and sequence to the rat and mouse genes. The overall structure of 9 exons separated by 8 introns is conserved among these three mammalian species. The nucleotide sequences of the human peripherin gene exons were 90% identical to the rat gene sequences, and the predicted human peripherin protein differed from rat peripherin at only 18 of 475 amino acid residues. Comparison of the 5{prime} flanking regions of the human peripherin gene and rodent genes revealed extensive areas of high homology. Additional conserved segments were found in introns 1 and 2. Within the 5{prime} region, potential regulatory sequences, including a nerve growth factor negative regulatory element, a Hox protein binding site, and a heat shock element, were identified in all peripherin genes. The positional conservation of each element suggests that they may be important in the tissue-specific, developmental-specific, and injury-specific expression of the peripherin gene. 24 refs., 2 figs., 1 tab.

  6. Phytoextraction of potentially toxic elements by Indian mustard, rapeseed, and sunflower from a contaminated riparian soil.

    PubMed

    Shaheen, Sabry M; Rinklebe, Jörg

    2015-12-01

    The objective of this study was to quantify the phytoextraction of the potentially toxic elements Al, As, Cd, Co, Cr, Cu, Mo, Ni, Pb, Se, V, and Zn by Indian mustard, rapeseed, and sunflower from a contaminated riparian soil. To achieve this goal, a greenhouse pot experiment was established using a highly contaminated grassland soil collected at the Wupper River (Germany). The impact of ethylene-diamine-tetra-acetic acid (EDTA), humate (HK), and phosphate potassium (PK) on the mobility and uptake of the elements by rapeseed also was investigated. Indian mustard showed the highest efficiency for phytoextraction of Al, Cr, Mo, Se, and V; sunflower for Cd, Ni, Pb, and Zn, and rapeseed for Cu. The bioconcentration ratios were higher than 1 for the elements (except As and Cu), indicating the suitability of the studied plants for phytoextraction. Application of EDTA to the soil increased significantly the solubility of Cd, Co, Cr, Ni, and Pb and decreased the solubility of Al, As, Se, V, and Mo. Humate potassium decreased significantly the concentrations of Al and As in rapeseed but increased the concentrations of Cu, Se, and Zn. We may conclude that HK can be used for immobilization of Al and As, while it can be used for enhancing the phytoextraction of Cu, Se, and Zn by rapeseed. Phosphate potassium immobilized Al, Cd, Pb, and Zn, but enhanced phytoextraction of As, Cr, Mo, and Se by rapeseed. PMID:26040974

  7. A potentially functional mariner transposable element in the protist Trichomonas vaginalis.

    PubMed

    Silva, Joana C; Bastida, Felix; Bidwell, Shelby L; Johnson, Patricia J; Carlton, Jane M

    2005-01-01

    Mariner transposable elements encoding a D,D34D motif-bearing transposase are characterized by their pervasiveness among, and exclusivity to, animal phyla. To date, several hundred sequences have been obtained from taxa ranging from cnidarians to humans, only two of which are known to be functional. Related transposons have been identified in plants and fungi, but their absence among protists is noticeable. Here, we identify and characterize Tvmar1, the first representative of the mariner family to be found in a species of protist, the human parasite Trichomonas vaginalis. This is the first D,D34D element to be found outside the animal kingdom, and its inclusion in the mariner family is supported by both structural and phylogenetic analyses. Remarkably, Tvmar1 has all the hallmarks of a functional element and has recently expanded to several hundred copies in the genome of T. vaginalis. Our results show that a new potentially active mariner has been found that belongs to a distinct mariner lineage and has successfully invaded a nonanimal, single-celled organism. The considerable genetic distance between Tvmar1 and other mariners may have valuable implications for the design of new, high-efficiency vectors to be used in transfection studies in protists.

  8. Conserved elements in the 3' untranslated region of flavivirus RNAs and potential cyclization sequences.

    PubMed

    Hahn, C S; Hahn, Y S; Rice, C M; Lee, E; Dalgarno, L; Strauss, E G; Strauss, J H

    1987-11-01

    We have isolated a cDNA clone after reverse transcription of the genomic RNA of Asibi yellow fever virus whose structure suggests it was formed by self-priming from a 3'-terminal hairpin of 87 nucleotides in the genomic RNA. We have also isolated a clone from cDNA made to Murray Valley encephalitis virus RNA that also appears to have arisen by self-priming from a 3'-terminal structure very similar or identical to that of yellow fever. In addition, 3'-terminal sequencing of the S1 strain of dengue 2 RNA shows that this RNA is also capable of forming a 3'-terminal hairpin of 79 nucleotides. Furthermore, we have identified two 20-nucleotide sequence elements which are present in the 3' untranslated region of all three viruses; one of these sequence elements is repeated in Murray Valley encephalitis and dengue 2 RNA but not in yellow fever RNA. In all three viruses, which represent the three major serological subgroups of the mosquito-borne flaviviruses, the 3'-proximal conserved sequence element, which is found immediately adjacent to the potential 3'-terminal hairpin, is complementary to another conserved domain near the 5' end of the viral RNAs, suggesting that flavivirus RNAs can cyclize (calculated delta G less than -11 kcal; 1 kcal = 4.184 kJ).

  9. Matrix-mediated retention of osteogenic differentiation potential by human adult bone marrow stromal cells during ex vivo expansion.

    PubMed

    Mauney, Joshua R; Kaplan, David L; Volloch, Vladimir

    2004-07-01

    During prolonged cultivation ex vivo, adult bone marrow stromal stem cells (BMSCs) undergo two probably interdependent processes, replicative aging and a decline in differentiation potential. Recently, our results with primary human fibroblasts indicated that growth on denatured collagen (DC) matrix results in the reduction of the rate of cellular aging. The present study has been undertaken to test whether the growth of human BMSCs under the same conditions would translate into preservation of cellular aging-attenuated functions, such as the ability to express HSP70 in response to stress as well as of osteogenic differentiation potential. We report here that growth of BMSCs on a DC matrix versus tissue culture polystyrene significantly reduced one of the main manifestations of cellular aging, the attenuation of the ability to express a major protective stress response component, HSP70, increased the proliferation capacity of ex vivo expanded BMSCs, reduced the rate of morphological changes, and resulted in a dramatic increase in the retention of the potential to express osteogenic-specific functions and markers upon treatment with osteogenic stimulants. BMSCs are a promising and increasingly important cell source for tissue engineering as well as cell and gene therapeutic strategies. For use of BMSCs in these applications, ex vivo expansion is necessary to obtain a sufficient, therapeutically useful, number of cells; however, this results in the loss of differentiation potential. This problem is especially acute in older patients where more extensive in vitro expansion of smaller number of stem/progenitor cells is needed. The finding that growth on certain biomaterials preserves aging-attenuated functions, enhances proliferation capacity, and maintains differentiation potential of BMSCs indicates a promising approach to address this problem.

  10. A unified derivation of Hamiltonian and optical transition matrix elements for open shell diatomic and polyatomic molecules using transformation tools of modern quantum mechanics.

    PubMed

    Schwenke, David W

    2015-04-14

    In this work, we systematically derive the matrix elements of the nuclear rotation operators for open shell diatomic and polyatomic molecules in a parity adapted Hund's case (a) basis. Our expressions are valid for an arbitrary number of electrons and arbitrary electronic configurations. The common ad hoc sign changes of angular momentum operators are shown to be equivalent to a change in phase of basis functions. We show how to relate this basis to that required for scattering calculations. We also give the expressions for Einstein A coefficients for electric dipole, electric quadrupole, and magnetic dipole transitions.

  11. A unified derivation of Hamiltonian and optical transition matrix elements for open shell diatomic and polyatomic molecules using transformation tools of modern quantum mechanics

    SciTech Connect

    Schwenke, David W.

    2015-04-14

    In this work, we systematically derive the matrix elements of the nuclear rotation operators for open shell diatomic and polyatomic molecules in a parity adapted Hund’s case (a) basis. Our expressions are valid for an arbitrary number of electrons and arbitrary electronic configurations. The common ad hoc sign changes of angular momentum operators are shown to be equivalent to a change in phase of basis functions. We show how to relate this basis to that required for scattering calculations. We also give the expressions for Einstein A coefficients for electric dipole, electric quadrupole, and magnetic dipole transitions.

  12. Nuclear matrix elements for 0νβ{sup −}β{sup −} decays: Comparative analysis of the QRPA, shell model and IBM predictions

    SciTech Connect

    Civitarese, Osvaldo; Suhonen, Jouni

    2013-12-30

    In this work we report on general properties of the nuclear matrix elements involved in the neutrinoless double β{sup −} decays (0νβ{sup −}β{sup −} decays) of several nuclei. A summary of the values of the NMEs calculated along the years by the Jyväskylä-La Plata collaboration is presented. These NMEs, calculated in the framework of the quasiparticle random phase approximation (QRPA), are compared with those of the other available calculations, like the Shell Model (ISM) and the interacting boson model (IBA-2)

  13. Matrix elements for the ground-state to ground-state 2{nu}{beta}{sup -}{beta}{sup -} decay of Te isotopes in a hybrid model

    SciTech Connect

    Bes, D. R.; Civitarese, O.

    2010-01-15

    Theoretical matrix elements, for the ground-state to ground-state two-neutrino double-{beta}-decay mode (2{nu}{beta}{sup -}{beta}{sup -}gs->gs) of {sup 128,130}Te isotopes, are calculated within a formalism that describes interactions between neutrons in a superfluid phase and protons in a normal phase. The elementary degrees of freedom of the model are proton-pair modes and pairs of protons and quasineutrons. The calculation is basically a parameter-free one, because all relevant parameters are fixed from the phenomenology. A comparison with the available experimental data is presented.

  14. FMO3-LCMO study of electron transfer coupling matrix element and pathway: Application to hole transfer between two tryptophans through cis- and trans-polyproline-linker systems

    NASA Astrophysics Data System (ADS)

    Kitoh-Nishioka, Hirotaka; Ando, Koji

    2016-09-01

    The linear-combination of fragment molecular orbitals with three-body correction (FMO3-LCMO) is examined for electron transfer (ET) coupling matrix elements and ET pathway analysis, with application to hole transfer between two tryptophans bridged by cis- and trans-polyproline linker conformations. A projection to the minimal-valence-plus-core FMO space was found to give sufficient accuracy with significant reduction of computational cost while avoiding the problem of linear dependence of FMOs stemming from involvement of bond detached atoms.

  15. A potential role for glia-derived extracellular matrix remodeling in postinjury epilepsy.

    PubMed

    Kim, Soo Young; Porter, Brenda E; Friedman, Alon; Kaufer, Daniela

    2016-09-01

    Head trauma and vascular injuries are known risk factors for acquired epilepsy. The sequence of events that lead from the initial injury to the development of epilepsy involves complex plastic changes and circuit rewiring. In-depth, comprehensive understanding of the epileptogenic process is critical for the identification of disease-modifying targets. Here we review the complex interactions of cellular and extracellular components that may promote epileptogenesis, with an emphasis on the role of astrocytes. Emerging evidence demonstrates that astrocytes promptly respond to brain damage and play a critical role in the development of postinjury epilepsy. Astrocytes have been shown to regulate extracellular matrix (ECM) remodeling, which can affect plasticity and stability of synapses and, in turn, contribute to the epileptogenic process. From these separate lines of evidence, we present a hypothesis suggesting a possible role for astrocyte-regulated remodeling of ECM and perineuronal nets, a specialized ECM structure around fast-spiking inhibitory interneurons, in the development and progression of posttraumatic epilepsies. © 2016 Wiley Periodicals, Inc. PMID:27265805

  16. Lability of potentially toxic elements in soils affected by smelting activities.

    PubMed

    Popescu, I; Biasioli, M; Ajmone-Marsan, F; Stănescu, R

    2013-01-01

    Determination of total concentration of potentially toxic elements (PTEs) in soil is not a reliable tool for evaluating potential exposure risk for humans. PTE lability (EDTA, SBET and solution extraction) and chemical speciation (BCR sequential extraction) were investigated for Pb, Cd, Cu, and Zn, as well as how these could be affected by flooding in soils polluted by smelting activities. The flooding experiment was performed in pots from which soil solution was extracted at different time intervals using Rhizon Moisture Samplers. After experiments, the soil was again subjected to the previous extractions (EDTA, SBET, and BCR) in order to reveal the changes which occurred during anoxia. From the results we can conclude that PTE lability is very high and flooding caused the increase in their mobility up to 100% (for bioaccessible Pb). The experiment demonstrated that temporary reducing conditions can increase the risk of contaminants passing to other environmental compartments and the food chain.

  17. Lability of potentially toxic elements in soils affected by smelting activities.

    PubMed

    Popescu, I; Biasioli, M; Ajmone-Marsan, F; Stănescu, R

    2013-01-01

    Determination of total concentration of potentially toxic elements (PTEs) in soil is not a reliable tool for evaluating potential exposure risk for humans. PTE lability (EDTA, SBET and solution extraction) and chemical speciation (BCR sequential extraction) were investigated for Pb, Cd, Cu, and Zn, as well as how these could be affected by flooding in soils polluted by smelting activities. The flooding experiment was performed in pots from which soil solution was extracted at different time intervals using Rhizon Moisture Samplers. After experiments, the soil was again subjected to the previous extractions (EDTA, SBET, and BCR) in order to reveal the changes which occurred during anoxia. From the results we can conclude that PTE lability is very high and flooding caused the increase in their mobility up to 100% (for bioaccessible Pb). The experiment demonstrated that temporary reducing conditions can increase the risk of contaminants passing to other environmental compartments and the food chain. PMID:23127724

  18. Matrix superpotentials

    NASA Astrophysics Data System (ADS)

    Nikitin, Anatoly G.; Karadzhov, Yuri

    2011-07-01

    We present a collection of matrix-valued shape invariant potentials which give rise to new exactly solvable problems of SUSY quantum mechanics. It includes all irreducible matrix superpotentials of the generic form W=kQ+\\frac{1}{k} R+P, where k is a variable parameter, Q is the unit matrix multiplied by a real-valued function of independent variable x, and P and R are the Hermitian matrices depending on x. In particular, we recover the Pron'ko-Stroganov 'matrix Coulomb potential' and all known scalar shape invariant potentials of SUSY quantum mechanics. In addition, five new shape invariant potentials are presented. Three of them admit a dual shape invariance, i.e. the related Hamiltonians can be factorized using two non-equivalent superpotentials. We find discrete spectrum and eigenvectors for the corresponding Schrödinger equations and prove that these eigenvectors are normalizable.

  19. Apparatus and method for identification of matrix materials in which transuranic elements are embedded using thermal neutron capture gamma-ray emission

    DOEpatents

    Close, D.A.; Franks, L.A.; Kocimski, S.M.

    1984-08-16

    An invention is described that enables the quantitative simultaneous identification of the matrix materials in which fertile and fissile nuclides are embedded to be made along with the quantitative assay of the fertile and fissile materials. The invention also enables corrections for any absorption of neutrons by the matrix materials and by the measurement apparatus by the measurement of the prompt and delayed neutron flux emerging from a sample after the sample is interrogated by simultaneously applied neutrons and gamma radiation. High energy electrons are directed at a first target to produce gamma radiation. A second target receives the resulting pulsed gamma radiation and produces neutrons from the interaction with the gamma radiation. These neutrons are slowed by a moderator surrounding the sample and bathe the sample uniformly, generating second gamma radiation in the interaction. The gamma radiation is then resolved and quantitatively detected, providing a spectroscopic signature of the constituent elements contained in the matrix and in the materials within the vicinity of the sample. (LEW)

  20. Induction of transcription within chromosomal DNA loops flanked by MAR elements causes an association of loop DNA with the nuclear matrix

    PubMed Central

    Iarovaia, Olga V.; Akopov, Sergey B.; Nikolaev, Lev G.; Sverdlov, Eugene D.; Razin, Sergey V.

    2005-01-01

    The spatial organization of an ∼170 kb region of human chromosome 19, including CD22 and GPR40–GPR43 genes, was studied using in situ hybridization of a set of cosmid and PAC probes with nuclear halos prepared from proliferating and differentiated HL60 cells. The whole region under study was found to be looped out into the nuclear halo in proliferating cells. It is likely that the loop observed was attached to the nuclear matrix via MAR elements present at the flanks of the area under study. Upon dimethyl sulfoxide-induced differentiation of the cells the looped fragment became associated with the nuclear matrix. This change in the spatial organization correlated with the activation of transcription of at least two (CD22 and GPR43) genes present within the loop. The data obtained are discussed in the framework of the hypothesis postulating that the spatial organization of chromosomal DNA is maintained via constitutive (basic) and facultative (transcription-related) interactions of the latter with the nuclear matrix. PMID:16049024

  1. Induction of transcription within chromosomal DNA loops flanked by MAR elements causes an association of loop DNA with the nuclear matrix.

    PubMed

    Iarovaia, Olga V; Akopov, Sergey B; Nikolaev, Lev G; Sverdlov, Eugene D; Razin, Sergey V

    2005-01-01

    The spatial organization of an approximately 170 kb region of human chromosome 19, including CD22 and GPR40-GPR43 genes, was studied using in situ hybridization of a set of cosmid and PAC probes with nuclear halos prepared from proliferating and differentiated HL60 cells. The whole region under study was found to be looped out into the nuclear halo in proliferating cells. It is likely that the loop observed was attached to the nuclear matrix via MAR elements present at the flanks of the area under study. Upon dimethyl sulfoxide-induced differentiation of the cells the looped fragment became associated with the nuclear matrix. This change in the spatial organization correlated with the activation of transcription of at least two (CD22 and GPR43) genes present within the loop. The data obtained are discussed in the framework of the hypothesis postulating that the spatial organization of chromosomal DNA is maintained via constitutive (basic) and facultative (transcription-related) interactions of the latter with the nuclear matrix. PMID:16049024

  2. Evaluation of matrix elements l angle n , l t bar r sup. beta. t bar n , l prime r angle for arbitrary. beta

    SciTech Connect

    Shertzer, J. )

    1991-09-01

    Simple expressions are obtained for diagonal matrix elements {l angle}{ital n},{ital l}{vert bar}{ital r}{sup {beta}}{vert bar}{ital n},{ital l}{r angle}, for arbitrary {beta} and fixed {ital l}, where {ital l}={ital n}{minus}1, {ital n}{minus}2, {ital n}{minus}3, {ital n}{minus}4, {ital n}{minus}5, {ital n}{minus}6, and {ital n}{minus}7. Off-diagonal matrix elements are also calculated for the special cases {l angle}{ital n},{ital l}{vert bar}{ital r}{sup {beta}}{vert bar}{ital n},{ital l}{plus minus}1{r angle} and {l angle}{ital n},{ital l}{vert bar}{ital r}{sup {beta}}{vert bar}{ital n},{ital l}{plus minus}2{r angle}. The expressions are valid for any real {beta}{ge}{minus}({ital l}+{ital l}{prime}+2).

  3. Relativistic correction to e{sup +}e{sup -{yields}}J/{psi}+gg at B factories and constraint on color-octet matrix elements

    SciTech Connect

    He Zhiguo; Fan Ying; Chao Kuangta

    2010-03-01

    We calculate the relativistic correction to J/{psi} production in the color-singlet process e{sup +}e{sup -{yields}}J/{psi}+gg at B factories. We employ the nonrelativistic QCD factorization approach, where the short-distance coefficients are calculated perturbatively and the long-distance matrix elements are extracted from the decays of J/{psi} into e{sup +}e{sup -} and light hadrons. We find that the O(v{sup 2}) relativistic correction can enhance the cross section by a factor of 20-30%, comparable to the enhancement due to the O({alpha}{sub s}) radiative correction obtained earlier. Combining the relativistic correction with the QCD radiative correction, we find that the color-singlet contribution to e{sup +}e{sup -{yields}}J/{psi}+gg can saturate the latest observed cross section {sigma}(e{sup +}e{sup -{yields}}J/{psi}+X{sub non-cc})=0.43{+-}0.09{+-}0.09 pb by Belle, thus leaving little room to the color-octet contributions. This gives a very stringent constraint on the color-octet contribution, and may imply that the values of color-octet matrix elements are much smaller than expected earlier by using the naive velocity scaling rules or extracted from fitting experimental data with the leading-order calculations.

  4. Potential of elemental sulfur fertigation to reduce high soil pH for production of highbush blueberry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Blueberry is adapted to acidic soil conditions but is often planted in high pH soils by adding elemental sulfur (S) prior to planting. Two pot experiments were carried out in a glasshouse to determine the potential of applying elemental S by fertigation through a drip irrigation system. In the first...

  5. Relativistic Quantum Chemistry of Heavy Elements: Interatomic potentials and Lines Shift for Systems 'Alkali Elements-Inert Gases'

    SciTech Connect

    Glushkov, A. V.; Khetselius, O.; Gurnitskaya, E.; Loboda, A.; Mischenko, E.

    2009-03-09

    New relativistic approach, based on the gauge-invariant perturbation theory (PT) with using the optimized wave functions basis's, is applied to calculating the inter atomic potentials, hyper fine structure (hfs) collision shift for alkali atoms in atmosphere of inert gases. Data for inter atomic potentials, collision shifts of the Rb and Cs atoms in atmosphere of the inert gas He are presented.

  6. The ab initio model potential method. Second series transition metal elements

    SciTech Connect

    Barandiaran, Z.; Seijo, L. ); Huzinaga, S. )

    1990-10-15

    The {ital ab} {ital initio} core method potential model (AIMP) has already been presented in its nonrelativistic version and applied to the main group and first series transition metal elements (J. Chem. Phys. {bold 86}, 2132 (1987); {bold 91}, 7011 (1989)). In this paper we extend the AIMP method to include relativistic effects within the Cowan--Griffin approximation and we present relativistic Zn-like core model potentials and valence basis sets, as well as their nonrelativistic Zn-like core and Kr-like core counterparts. The pilot molecular calculations on YO, TcO, AgO, and AgH reveal that the 4{ital p} orbital is indeed a core orbital only at the end part of the series, whereas the 4{ital s} orbital can be safely frozen from Y to Cd. The all-electron and model potential results agree in 0.01--0.02 A in {ital R}{sub {ital e}} and 25--50 cm{sup {minus}1} in {bar {nu}}{sub {ital e}} if the same type of valence part of the basis set is used. The comparison of the relativistic results on AgH with those of the all-electron Dirac--Fock calculations by Lee and McLean is satisfactory: the absolute value of {ital R}{sub {ital e}} is reproduced within the 0.01 A margin and the relativistic contraction of 0.077 A is also very well reproduced (0.075 A). Finally, the relative magnitude of the effects of the core orbital change, mass--velocity potential, and Darwin potential on the net relativistic effects are analyzed in the four molecules studied.

  7. Invertibility of retarded response functions for Laplace transformable potentials: Application to one-body reduced density matrix functional theory.

    PubMed

    Giesbertz, K J H

    2015-08-01

    A theorem for the invertibility of arbitrary response functions is presented under the following conditions: the time dependence of the potentials should be Laplace transformable and the initial state should be a ground state, though it might be degenerate. This theorem provides a rigorous foundation for all density-functional-like theories in the time-dependent linear response regime. Especially for time-dependent one-body reduced density matrix (1RDM) functional theory, this is an important step forward, since a solid foundation has currently been lacking. The theorem is equally valid for static response functions in the non-degenerate case, so can be used to characterize the uniqueness of the potential in the ground state version of the corresponding density-functional-like theory. Such a classification of the uniqueness of the non-local potential in ground state 1RDM functional theory has been lacking for decades. With the aid of presented invertibility theorem presented here, a complete classification of the non-uniqueness of the non-local potential in 1RDM functional theory can be given for the first time.

  8. Two-electron R-matrix approach to calculations of potential-energy curves of long-range Rydberg molecules

    NASA Astrophysics Data System (ADS)

    Tarana, Michal; Čurík, Roman

    2016-05-01

    We introduce a computational method developed for study of long-range molecular Rydberg states of such systems that can be approximated by two electrons in a model potential of the atomic cores. The method is based on a two-electron R-matrix approach inside a sphere centered on one of the atoms. The wave function is then connected to a Coulomb region outside the sphere via a multichannel version of the Coulomb Green's function. This approach is applied to a study of Rydberg states of Rb2 for internuclear separations R from 40 to 320 bohrs and energies corresponding to n from 7 to 30. We report bound states associated with the low-lying 3Po resonance and with the virtual state of the rubidium atom that turn into ion-pair-like bound states in the Coulomb potential of the atomic Rydberg core. The results are compared with previous calculations based on single-electron models employing a zero-range contact-potential and short-range modele potential. Czech Science Foundation (Project No. P208/14-15989P).

  9. GENERAL: An improved boundary element-free method (IBEFM) for two-dimensional potential problems

    NASA Astrophysics Data System (ADS)

    Ren, Hong-Ping; Cheng, Yu-Min; Zhang, Wu

    2009-10-01

    The interpolating moving least-squares (IMLS) method is discussed first in this paper. And the formulae of the IMLS method obtained by Lancaster are revised. Then on the basis of the boundary element-free method (BEFM), combining the boundary integral equation (BIE) method with the IMLS method, the improved boundary element-free method (IBEFM) for two-dimensional potential problems is presented, and the corresponding formulae of the IBEFM are obtained. In the BEFM, boundary conditions are applied directly, but the shape function in the MLS does not satisfy the property of the Kronecker δ function. This is a problem of the BEFM, and must be solved theoretically. In the IMLS method, when the shape function satisfies the property of the Kronecker δ function, then the boundary conditions, in the meshless method based on the IMLS method, can be applied directly. Then the IBEFM, based on the IMLS method, is a direct meshless boundary integral equation method in which the basic unknown quantity is the real solution of the nodal variables, and the boundary conditions can be applied directly and easily, thus it gives a greater computational precision. Some numerical examples are presented to demonstrate the method.

  10. A potential link among antioxidant enzymes, histopathology and trace elements in canine visceral leishmaniasis

    PubMed Central

    Souza, Carolina C; Barreto, Tatiane de O; da Silva, Sydnei M; Pinto, Aldair W J; Figueiredo, Maria M; Ferreira Rocha, Olguita G; Cangussú, Silvia D; Tafuri, Wagner L

    2014-01-01

    Canine visceral leishmaniasis (CVL) is a severe and fatal systemic chronic inflammatory disease. We investigated the alterations in, and potential associations among, antioxidant enzymes, trace elements and histopathology in CVL. Blood and tissue levels of Cu-Zn superoxide dismutase, catalase and glutathione peroxidase were measured in mixed-breed dogs naturally infected with Leishmania infantum chagasi, symptomatic (n = 19) and asymptomatic (n = 11). Serum levels of copper, iron, zinc, selenium and nitric oxide, and plasma lipid peroxidation were measured. Histological and morphometric analyses were conducted of lesions in liver, spleen and lymph nodes. We found lower blood catalase and glutathione peroxidase activity to be correlated with lower iron and selenium respectively. However, higher activity of Cu-Zn superoxide dismutase was not correlated with the increase in copper and decreased in zinc observed in infected animals compared to controls. Organ tissue was characterized by lower enzyme activity in infected dogs than in controls, but this was not correlated with trace elements. Lipid peroxidation was higher in symptomatic than in asymptomatic and control dogs and was associated with lesions such as chronic inflammatory reaction, congestion, haemosiderin and fibrosis. Systemic iron deposition was observed primarily in the symptomatic dogs showing a higher tissue parasite load. Dogs with symptomatic CVL displayed enhanced LPO and Fe tissue deposition associated with decreased levels of antioxidant enzymes. These results showed new points in the pathology of CVL and might open new treatment perspectives associated with antioxidants and the role of iron in the pathogenesis of CVL. PMID:24766461

  11. The potential of pulsed low intensity ultrasound to stimulate chondrocytes matrix synthesis in agarose and monolayer cultures.

    PubMed

    Vaughan, Natalie M; Grainger, James; Bader, Dan L; Knight, Martin M

    2010-12-01

    Pulsed low intensity ultrasound (PLIUS) has been used successfully for bone fracture repair and has therefore been suggested for cartilage regeneration. However, previous in vitro studies with chondrocytes show conflicting results as to the effect of PLIUS on the elaboration of extracellular matrix. This study tests the hypothesis that PLIUS, applied for 20 min/day, stimulates the synthesis of sulphated glycosaminoglycan (sGAG) by adult bovine articular chondrocytes cultured in either monolayer or agarose constructs. For both culture models, PLIUS at either 30 or 100 mW/cm(2) intensity had no net effect on the total sGAG content. Although PLIUS at 100 mW/cm(2) did induce a 20% increase in sGAG content at day 2 of culture in agarose, this response was lost by day 5. Intensities of 200 and 300 mW/cm(2) resulted in cell death probably due to heating from the ultrasound transducers. The lack of a sustained up-regulation of sGAG synthesis may reflect the suggestion that PLIUS only induces a stimulatory effect in the presence of a tissue injury response. These results suggest that PLIUS has a limited potential to provide an effective method of stimulating matrix production as part of a tissue engineering strategy for cartilage repair. PMID:20938751

  12. Expression of Matrix Metalloproteinase (MMP)-20 and Potential Interaction with Dentin Sialophosphoprotein (DSPP) in Human Major Salivary Glands.

    PubMed

    Koli, Komal; Saxena, Geetu; Ogbureke, Kalu U E

    2015-07-01

    Matrix metalloproteinase-20 (MMP-20) expression is widely regarded as tooth-specific, with expression limited to dental hard tissues. Necessary for sound enamel formation, MMP-20 and MMP-2 proteolytically process dentin sialophosphoprotein (DSPP) into dentin sialoprotein, dentin phosphoprotein, and dentin glycoprotein during tooth formation. In the mid-2000s, three members of the small integrin-binding ligand N-linked glycoproteins (SIBLINGs) were reported to bind specifically with high affinity (nM) to, and activate, three MMPs in vitro: bone sialoprotein with MMP-2; osteopontin with MMP-3; and dentin matrix protein1 with MMP-9. The SIBLING-MMP interaction was confirmed in biological systems such as the ducts of salivary glands, where all five members of the SIBLINGs are expressed. Recently, we documented MMP-20 expression and interaction with DSPP (another member of the SIBLING family) in human oral squamous cell carcinoma. Here we report the expression of MMP-20, and confirm its co-expression and potential interaction with DSPP in human major salivary gland tissues and cell line using immunohistochemistry, immunofluorescence, western blot, quantitative RT-PCR, and proximity ligation assay. This report reinforces our earlier suggestion that the SIBLING-MMP complexes may be involved in the turnover of extracellular proteins damaged by oxidation byproducts in metabolically active duct epithelial systems.

  13. Phytobarriers: Plants capture particles containing potentially toxic elements originating from mine tailings in semiarid regions.

    PubMed

    Sánchez-López, Ariadna S; Carrillo-González, Rogelio; González-Chávez, Ma Del Carmen Angeles; Rosas-Saito, Greta Hanako; Vangronsveld, Jaco

    2015-10-01

    Retention of particles containing potentially toxic elements (PTEs) on plants that spontaneously colonize mine tailings was studied through comparison of washed and unwashed shoot samples. Zn, Pb, Cd, Cu, Ni, Co and Mn concentrations were determined in plant samples. Particles retained on leaves were examined by Scanning Electronic Microscopy and energy dispersive X-Ray analysis. Particles containing PTEs were detected on both washed and unwashed leaves. This indicates that the thorough washing procedure did not remove all the particles containing PTEs from the leaf surface, leading to an overestimation of the concentrations of PTEs in plant tissues. Particularly trichomes and fungal mycelium were retaining particles. The quantity and composition of particles varied among plant species and place of collection. It is obvious that plants growing on toxic mine tailings form a physical barrier against particle dispersion and hence limit the spread of PTEs by wind.

  14. Arsenic: A Review of the Element's Toxicity, Plant Interactions, and Potential Methods of Remediation.

    PubMed

    Hettick, Bryan E; Cañas-Carrell, Jaclyn E; French, Amanda D; Klein, David M

    2015-08-19

    Arsenic is a naturally occurring element with a long history of toxicity. Sites of contamination are found worldwide as a result of both natural processes and anthropogenic activities. The broad scope of arsenic toxicity to humans and its unique interaction with the environment have led to extensive research into its physicochemical properties and toxic behavior in biological systems. The purpose of this review is to compile the results of recent studies concerning the metalloid and consider the chemical and physical properties of arsenic in the broad context of human toxicity and phytoremediation. Areas of focus include arsenic's mechanisms of human toxicity, interaction with plant systems, potential methods of remediation, and protocols for the determination of metals in experimentation. This assessment of the literature indicates that controlling contamination of water sources and plants through effective remediation and management is essential to successfully addressing the problems of arsenic toxicity and contamination.

  15. A finite-element visualization of quantum reactive scattering. II. Nonadiabaticity on coupled potential energy surfaces

    NASA Astrophysics Data System (ADS)

    Warehime, Mick; Kłos, Jacek; Alexander, Millard H.

    2015-01-01

    This is the second in a series of papers detailing a MATLAB based implementation of the finite element method applied to collinear triatomic reactions. Here, we extend our previous work to reactions on coupled potential energy surfaces. The divergence of the probability current density field associated with the two electronically adiabatic states allows us to visualize in a novel way where and how nonadiabaticity occurs. A two-dimensional investigation gives additional insight into nonadiabaticity beyond standard one-dimensional models. We study the F(2P) + HCl and F(2P) + H2 reactions as model applications. Our publicly available code (http://www2.chem.umd.edu/groups/alexander/FEM) is general and easy to use.

  16. A finite-element visualization of quantum reactive scattering. II. Nonadiabaticity on coupled potential energy surfaces

    SciTech Connect

    Warehime, Mick; Kłos, Jacek; Alexander, Millard H.

    2015-01-21

    This is the second in a series of papers detailing a MATLAB based implementation of the finite element method applied to collinear triatomic reactions. Here, we extend our previous work to reactions on coupled potential energy surfaces. The divergence of the probability current density field associated with the two electronically adiabatic states allows us to visualize in a novel way where and how nonadiabaticity occurs. A two-dimensional investigation gives additional insight into nonadiabaticity beyond standard one-dimensional models. We study the F({sup 2}P) + HCl and F({sup 2}P) + H{sub 2} reactions as model applications. Our publicly available code (http://www2.chem.umd.edu/groups/alexander/FEM) is general and easy to use.

  17. Temporal dissolution of potentially toxic elements from silver smelting slag by synthetic environmental solutions.

    PubMed

    Ash, Christopher; Borůvka, Luboš; Tejnecký, Václav; Šebek, Ondřej; Nikodem, Antonín; Drábek, Ondřej

    2013-11-15

    Waste slag which is created during precious metal smelting contains high levels of potentially toxic elements (PTE) which can be mobilised from unconfined deposits into the local environment. This paper examines the extractability of selected PTE (Pb, Zn, Cd, Mn) from slag samples by synthetic solutions designed to replicate those in the environment. Extracting agents were used to replicate potential leaching scenarios which are analogous to natural chemical weathering. Slag was submersed in a rainwater simulation solution (RSS), weak citric acid solution (representing rhizosphere secretions) and control solutions (deionised water) for a one month period with solution analyses made at intervals of 1, 24, 168 and 720 h. In 1 mM citric acid, dissolution of Cd and Zn showed little change with time, although for Zn the initial dissolution was considerable. Lead in citric acid was characterized by overall poor extractability. Mn solubility increased until an equilibrium state occurred within 24 h. The solubility of studied metals in citric acid can be characterized by a short time to equilibrium. RSS proved to be an effective solvent that, unlike citric acid solution, extracted increasing concentrations of Cd, Mn and Zn with time. Solubility of Pb in RSS was again very low. When taken as a proportion of a single 2 M HNO3 extraction which was applied to slag samples, Cd was the element most readily leached into RSS and control samples. In both studied solvents, slag heterogeneity is prominent in the case of Cd and Zn solubility. Contact time with solvent appears to be an important variable for the release of PTE from slag into solution. The purpose of this study was to provide insight into the environmental chemical dissolution of PTE from slag, which causes their enrichment in surrounding soils and surface waters. PMID:23920416

  18. Differential bioaccumulation of potentially toxic elements in benthic and pelagic food chains in Lake Baikal.

    PubMed

    Ciesielski, Tomasz M; Pastukhov, Mikhail V; Leeves, Sara A; Farkas, Julia; Lierhagen, Syverin; Poletaeva, Vera I; Jenssen, Bjørn M

    2016-08-01

    Lake Baikal is located in eastern Siberia in the center of a vast mountain region. Even though the lake is regarded as a unique and pristine ecosystem, there are existing sources of anthropogenic pollution to the lake. In this study, the concentrations of the potentially toxic trace elements As, Cd, Pb, Hg, and Se were analyzed in water, plankton, invertebrates, and fish from riverine and pelagic influenced sites in Lake Baikal. Concentrations of Cd, Hg, Pb and Se in Lake Baikal water and biota were low, while concentrations of As were similar or slightly higher compared to in other freshwater ecosystems. The bioaccumulation potential of the trace elements in both the pelagic and the benthic ecosystems differed between the Selenga Shallows (riverine influence) and the Listvenichnyĭ Bay (pelagic influence). Despite the one order of magnitude higher water concentrations of Pb in the Selenga Shallows, Pb concentrations were significantly higher in both pelagic and benthic fish from the Listvenichnyĭ Bay. A similar trend was observed for Cd, Hg, and Se. The identified enhanced bioavailability of contaminants in the pelagic influenced Listvenichnyĭ Bay may be attributed to a lower abundance of natural ligands for contaminant complexation. Hg was found to biomagnify in both benthic and pelagic Baikal food chains, while As, Cd, and Pb were biodiluted. At both locations, Hg concentrations were around seven times higher in benthic than in pelagic fish, while pelagic fish had two times higher As concentrations compared to benthic fish. The calculated Se/Hg molar ratios revealed that, even though Lake Baikal is located in a Se-deficient region, Se is still present in excess over Hg and therefore the probability of Hg induced toxicity in the endemic fish species of Lake Baikal is assumed to be low. PMID:27130338

  19. Temporal dissolution of potentially toxic elements from silver smelting slag by synthetic environmental solutions.

    PubMed

    Ash, Christopher; Borůvka, Luboš; Tejnecký, Václav; Šebek, Ondřej; Nikodem, Antonín; Drábek, Ondřej

    2013-11-15

    Waste slag which is created during precious metal smelting contains high levels of potentially toxic elements (PTE) which can be mobilised from unconfined deposits into the local environment. This paper examines the extractability of selected PTE (Pb, Zn, Cd, Mn) from slag samples by synthetic solutions designed to replicate those in the environment. Extracting agents were used to replicate potential leaching scenarios which are analogous to natural chemical weathering. Slag was submersed in a rainwater simulation solution (RSS), weak citric acid solution (representing rhizosphere secretions) and control solutions (deionised water) for a one month period with solution analyses made at intervals of 1, 24, 168 and 720 h. In 1 mM citric acid, dissolution of Cd and Zn showed little change with time, although for Zn the initial dissolution was considerable. Lead in citric acid was characterized by overall poor extractability. Mn solubility increased until an equilibrium state occurred within 24 h. The solubility of studied metals in citric acid can be characterized by a short time to equilibrium. RSS proved to be an effective solvent that, unlike citric acid solution, extracted increasing concentrations of Cd, Mn and Zn with time. Solubility of Pb in RSS was again very low. When taken as a proportion of a single 2 M HNO3 extraction which was applied to slag samples, Cd was the element most readily leached into RSS and control samples. In both studied solvents, slag heterogeneity is prominent in the case of Cd and Zn solubility. Contact time with solvent appears to be an important variable for the release of PTE from slag into solution. The purpose of this study was to provide insight into the environmental chemical dissolution of PTE from slag, which causes their enrichment in surrounding soils and surface waters.

  20. A Fast, Robust Matrix-Free Multi-level Preconditioner for Hybrid Marker-In-Cell Q2-P1 Finite Element Discretisations with Applications to Lithospheric Deformation

    NASA Astrophysics Data System (ADS)

    May, D. A.; Le Pourhiet, L.

    2012-12-01

    The use of a mixed finite element formulation to discretise Stokes equations, coupled with a particle based Lagrangian representation of the material lithology is a common numerical technique employed within geodynamics to study large deformation processes. The extension of this methodology to enable high-resolution, three-dimensional simulations still represents a number of significant computational challenges. Of most concern are the high computational memory requirements of the favoured Q2-P1 element, and the development of efficient, 'light-weight' and robust linear and non-linear solvers, which are performant on multi-core, massively parallel computational hardware. Our objective is to develop a 'cheap' and efficient methodology utilizing the mixed element Q2-P1, to study 3D geodynamic processes including subduction, rifting and folding with the inclusion of visco-plastic materials. For this class of problems, careful treatment of all of the aforementioned technical challenges is essential to achieve high resolution simulations. Here, I describe a flexible methodology which aims to rectify all of these issues. The key to the approach is 1) always pose the discrete problem in defect-correction form and 2) utilise a mixture of assembled and matrix-free operations to evaluate the non-linear residual and apply the operators and smoothers required to define the multi-level preconditioner for the Jacobian. The performance characteristics of the matrix-free, multi-level preconditioning strategy is demonstrated by considering several 3D visco-plastic models. The robustness of the preconditioner and non-linear solver with respect to the viscosity contrast and the topology of the viscosity field, together with the parallel scalability will be demonstrated.

  1. Trace element behaviour at cold seeps and the potential export of dissolved iron to the ocean

    NASA Astrophysics Data System (ADS)

    Lemaitre, Nolwenn; Bayon, Germain; Ondréas, Hélène; Caprais, Jean-Claude; Freslon, Nicolas; Bollinger, Claire; Rouget, Marie-Laure; de Prunelé, Alexis; Ruffine, Livio; Olu-Le Roy, Karine; Sarthou, Géraldine

    2014-10-01

    Seawater samples were collected by submersible above methane seeps in the Gulf of Guinea (Regab and Baboon pockmarks) in order to investigate the behaviour of iron (Fe), manganese (Mn) and rare earth elements (REE) during fluid seepage. Our aim was to determine whether cold seeps may represent potential sources of dissolved chemical species to the ocean. Dissolved (<0.45 μm filtered samples) and total dissolvable (unfiltered samples) concentrations were determined over ∼50 m long vertical transects above the seafloor and at various discrete locations within the pockmarks. We show that substantial amounts of Fe and Mn are released into seawater during seepage of methane-rich fluids. Mn is exported almost quantitatively in the dissolved form (more than 90% of total Mn; mean MnDISS∼12±11 nmol/kg). Although a significant fraction of Fe is bound to particulate phases, the dissolved iron pool still accounts on average for approximately 20 percent of total iron flux at vent sites (mean FeDISS∼22±11 nmol/kg). This dissolved Fe fraction also appears to remain stable in the water column. In contrast, there was no evidence for any significant benthic fluxes of pore water REE associated with fluid seepage at the studied sites. Overall, our results point towards distinct trace element behaviour during fluid seepage, with potential implications for the marine geochemical budget. The absence of any dissolved REE enrichments in bottom waters clearly indicates effective removal in sub-surface sediments. Most likely, precipitation of authigenic mineral phases at cold seeps (i.e. carbonates) represents a net sink for these elements. While Mn appears to behave near-conservatively during fluid seepage, the observed relative stability of dissolved Fe in the water column above seepage sites could be explained by complexation with strong organic ligands and/or the presence of Fe-bearing sulfide nanoparticles, as reported previously for submarine hydrothermal systems. Considering

  2. The Force Exerted by the Membrane Potential During Protein Import into the Mitochondrial Matrix

    NASA Technical Reports Server (NTRS)

    Shariff, Karim; Ghosal, Sandip; Matouschek, Andreas

    2002-01-01

    The electrostatic force exerted on a targeting sequence by the electrical potential across the inner mitochondrial membrane is calculated and found to vary from 1.4 pN to 2.2 pN (per unit elementary charge) as the radius of the inner membrane pore (assumed aqueous) is varied from 12 to 6.5 Angstroms, its measured range. Since the pore is not very much wider than the distance between water molecules, the full shielding effect of water may not be present; the extreme case of a nonaqueous pore gives a force of 3.1 pN per unit charge, which represents an upper limit. When applied to mitochondrial import experiments on the protein harness, these results imply that a force of 11 plus or minus 4 pN is sufficient to catalyze the unfolding of harness during import. Comparison of these results with unfolding forces measured using atomic force microscopy suggests that the two are not inconsistent.

  3. The force exerted by the membrane potential during protein import into the mitochondrial matrix

    NASA Technical Reports Server (NTRS)

    Shariff, Karim; Ghosal, Sandip; Matouschek, Andreas

    2004-01-01

    The force exerted on a targeting sequence by the electrical potential across the inner mitochondrial membrane is calculated on the basis of continuum electrostatics. The force is found to vary from 3.0 pN to 2.2 pN (per unit elementary charge) as the radius of the inner membrane pore (assumed aqueous) is varied from 6.5 to 12 A, its measured range. In the present model, the decrease in force with increasing pore width arises from the shielding effect of water. Since the pore is not very much wider than the distance between water molecules, the full shielding effect of water may not be present; the extreme case of a purely membranous pore without water gives a force of 3.2 pN per unit charge, which should represent an upper limit. When applied to mitochondrial import experiments on the protein barnase, these results imply that forces between 11 +/- 2 pN and 13.5 +/- 2.5 pN catalyze the unfolding of barnase in those experiments. A comparison of these results with unfolding forces measured using atomic force microscopy is made.

  4. Preliminary in vivo studies on the osteogenic potential of bone morphogenetic proteins delivered from an absorbable puttylike polymer matrix.

    PubMed

    Andriano, K P; Chandrashekar, B; McEnery, K; Dunn, R L; Moyer, K; Balliu, C M; Holland, K M; Garrett, S; Huffer, W E

    2000-01-01

    This article describes preliminary in vivo studies evaluating the osteogeneic potential of bone morphogenetic proteins (BMPs) delivered from an absorbable puttylike polymer matrix. In the first study, bovine-derived bone morphogenetic proteins were incorporated in an polymer matrix consisting of 50:50 poly(DL-lactide-co-glycolide) dissolved in N-methyl-2-pyrrolidone. The matrix was implanted in an 8 mm critical-size calvarial defect created in the skull of adult Sprague-Dawley rats (n = 5 per treatment group). After 28 days, the implant sites were removed and examined for new bone formation, polymer degradation, and tissue reaction. Gamma-irradiated polymer matrices appeared to give more bone formation than nonirradiated samples (histological analysis; 2. 76 + 1.34 mm(2) of bone versus 1.30 + 0.90 mm(2) of bone, respectively and x-ray analysis; 27.2 + 15.9 mm(2) of bone versus 20. 7 + 16.7 mm(2) of bone, respectively) and less residual polymer (0.0 + 0.0 versus 0.2 + 0.4, respectively). The polymer implants with bone morphogenetic protein also gave less inflammatory response than the polymer controls (gamma irradiated polymer/BMP = 1.8 + 0.4 and nonirradiated polymer/BMP = 1.2 + 0.4 versus polymer only = 3.0 + 1. 2, respectively). However, despite trends in both the x-ray and histological data there was no statistical difference in the amount of new bone formed among the four treatment groups (P > 0.05). This was most likely due to the large variance in the data scatter and the small number of animals per group. In the second animal study, bovine-derived BMPs and the polymeric carrier were gamma irradiated separately, at doses of 1.5 or 2.5 Mrad, and their ability to form bone in a rat skull onlay model was evaluated using Sprague-Dawley rats (n = 5 per treatment group). Histomorphometry of skull caps harvested 28 days after implantation showed no significant differences as compared to non-irradiated samples, in implant area, new bone area, and percent new bone (P

  5. Beam studies of the segmented resistive WELL: A potential thin sampling element for digital hadron calorimetry

    NASA Astrophysics Data System (ADS)

    Arazi, Lior; Davide Rocha Azevedo, Carlos; Breskin, Amos; Bressler, Shikma; Moleri, Luca; Natal da Luz, Hugo; Oliveri, Eraldo; Pitt, Michael; Rubin, Adam; Marques Ferreira dos Santos, Joaquim; Filipe Calapez de Albuquerque Veloso, João; Paul White, Andrew

    2013-12-01

    Thick Gas Electron Multipliers (THGEMs) have the potential of constituting thin, robust sampling elements in Digital Hadron Calorimetry (DHCAL) at future colliders. We report on recent beam studies of new single- and double-THGEM-like structures: the multiplier is a Segmented Resistive WELL (SRWELL) - a single-faced THGEM in contact with a segmented resistive layer inductively coupled to readout pads. Several 10×10 cm2 configurations with a total thickness of 5-6 mm (excluding electronics) with 1 cm2 pads were investigated with muons and pions. The pads were coupled to a scalable readout system APV chip, APV-SRS (Raymond et al. [22]). Detection efficiencies in the 98% range were recorded with an average pad-multiplicity of ~1.1. The resistive anode resulted in efficient discharge damping, with potential drops of a few volts; the discharge probabilities were ~10-7 for muons and ~10-6 for pions, at rates of a few kHz/cm2 and for detectors in the double-stage configuration. Further optimization work and research on larger detectors are underway.

  6. Measurement of the Top Quark Mass at D0 Run II with the Matrix Element Method in the Lepton+Jets Final State

    SciTech Connect

    Schieferdecker, Philipp

    2005-08-05

    The mass of the top quark is a fundamental parameter of the Standard Model. Its precise knowledge yields valuable insights into unresolved phenomena in and beyond the Standard Model. A measurement of the top quark mass with the matrix element method in the lepton+jets final state in D0 Run II is presented. Events are selected requiring an isolated energetic charged lepton (electron or muon), significant missing transverse energy, and exactly four calorimeter jets. For each event, the probabilities to originate from the signal and background processes are calculated based on the measured kinematics, the object resolutions and the respective matrix elements. The jet energy scale is known to be the dominant source of systematic uncertainty. The reference scale for the mass measurement is derived from Monte Carlo events. The matrix element likelihood is defined as a function of both, m{sub top} and jet energy scale JES, where the latter represents a scale factor with respect to the reference scale. The top mass is obtained from a two-dimensional correlated fit, and the likelihood yields both the statistical and jet energy scale uncertainty. Using a dataset of 320 pb-1 of D0 Run II data, the mass of the top quark is measured to be: m$ℓ+jets\\atop{top}$ = 169.5 ± 4.4(stat. + JES)$+1.7\\atop{-1.6}$(syst.) GeV; m$e+jets\\atop{top}$ = 168.8 ± 6.0(stat. + JES)$+1.9\\atop{-1.9}$(syst.) GeV; m$μ+jets\\atop{top}$ = 172.3 ± 9.6(stat.+JES)$+3.4\\atop{-3.3}$(syst.) GeV. The jet energy scale measurement in the ℓ+jets sample yields JES = 1.034 ± 0.034, suggesting good consistency of the data with the simulation. The measurement forecasts significant improvements to the total top mass uncertainty during Run II before the startup of the LHC, as the data sample will grow by a factor of ten and D0's tracking capabilities will be employed in jet energy reconstruction and flavor identification.

  7. Top Quark Produced Through the Electroweak Force: Discovery Using the Matrix Element Analysis and Search for Heavy Gauge Bosons Using Boosted Decision Trees

    SciTech Connect

    Pangilinan, Monica

    2010-05-01

    The top quark produced through the electroweak channel provides a direct measurement of the Vtb element in the CKM matrix which can be viewed as a transition rate of a top quark to a bottom quark. This production channel of top quark is also sensitive to different theories beyond the Standard Model such as heavy charged gauged bosons termed W'. This thesis measures the cross section of the electroweak produced top quark using a technique based on using the matrix elements of the processes under consideration. The technique is applied to 2.3 fb-1 of data from the D0 detector. From a comparison of the matrix element discriminants between data and the signal and background model using Bayesian statistics, we measure the cross section of the top quark produced through the electroweak mechanism σ(p$\\bar{p}$ → tb + X, tqb + X) = 4.30-1.20+0.98 pb. The measured result corresponds to a 4.9σ Gaussian-equivalent significance. By combining this analysis with other analyses based on the Bayesian Neural Network (BNN) and Boosted Decision Tree (BDT) method, the measured cross section is 3.94 ± 0.88 pb with a significance of 5.0σ, resulting in the discovery of electroweak produced top quarks. Using this measured cross section and constraining |Vtb| < 1, the 95% confidence level (C.L.) lower limit is |Vtb| > 0.78. Additionally, a search is made for the production of W' using the same samples from the electroweak produced top quark. An analysis based on the BDT method is used to separate the signal from expected backgrounds. No significant excess is found and 95% C.L. upper limits on the production cross section are set for W' with masses within 600-950 GeV. For four general models of W{prime} boson production using decay channel W' → t$\\bar{p}$, the lower mass limits are the following: M(W'L with SM couplings) > 840 GeV; M(W'R) > 880 GeV or 890 GeV if the right-handed neutrino is

  8. Exact analytical expressions and numerical analysis of two-center Franck Condon factors and matrix elements over displaced harmonic oscillator wave functions

    NASA Astrophysics Data System (ADS)

    Guseinov, I. I.; Mamedov, B. A.; Ekenoğlu, A. S.

    2006-08-01

    A detailed study is undertaken, using various techniques, in deriving analytical formula of Franck-Condon overlap integrals and matrix elements of various functions of power (x), exponential (exp(-2cx)) and Gaussian (exp(-cx)) over displaced harmonic oscillator wave functions with arbitrary frequencies. The results suggested by previous experience with various algorithms are presented in mathematically compact form and consist of generalization. The relationships obtained are valid for the arbitrary values of parameters and the computation results are in good agreement with the literature. The numerical results illustrate clearly a further reduction in calculation times. Program summaryProgram name:FRANCK Catalogue identifier:ADXX_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADXX_v1_0 Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland Programming language:Mathematica 5.0 Computer:Pentium M 1.4 GHz Operating system:Mathematica 5.0 RAM:512 MB No. of lines in distributed program, including test data, etc.:825 No. of bytes in distributed program, including test data, etc.:16 344 Distribution format:tar.gz Nature of problem:The programs calculate the Franck-Condon factors and matrix elements over displaced harmonic oscillator wave functions with arbitrary quantum numbers (n,n), frequencies (a,a) and displacement (d) for the various functions of power (x), exponential (exp(-2cx)) and Gaussian (exp(-cx)). Solution method:The Franck-Condon factors and matrix elements are evaluated using binomial coefficients and basic integrals. Restrictions:The results obtained by the present programs show great numerical stability for arbitrary quantum numbers (n,n), frequencies (a,a) and displacement (d). Unusual features:None Running time:As an example, for the value of Franck-Condon Overlap Integral I(d;α,α)=0.004405001887372332 with n=3, n=2, a=4, a=3, d=2, the compilation time in a Pentium M 1.4 GHz computer is 0.18 s. Execution

  9. Fault diagnosis of rolling element bearing based on S transform and gray level co-occurrence matrix

    NASA Astrophysics Data System (ADS)

    Zhao, Minghang; Tang, Baoping; Tan, Qian

    2015-08-01

    Time-frequency analysis is an effective tool to extract machinery health information contained in non-stationary vibration signals. Various time-frequency analysis methods have been proposed and successfully applied to machinery fault diagnosis. However, little research has been done on bearing fault diagnosis using texture features extracted from time-frequency representations (TFRs), although they may contain plenty of sensitive information highly related to fault pattern. Therefore, to make full use of the textural information contained in the TFRs, this paper proposes a novel fault diagnosis method based on S transform, gray level co-occurrence matrix (GLCM) and multi-class support vector machine (Multi-SVM). Firstly, S transform is chosen to generate the TFRs due to its advantages of providing frequency-dependent resolution while keeping a direct relationship with the Fourier spectrum. Secondly, the famous GLCM-based texture features are extracted for capturing fault pattern information. Finally, as a classifier which has good discrimination and generalization abilities, Multi-SVM is used for the classification. Experimental results indicate that the GLCM-based texture features extracted from TFRs can identify bearing fault patterns accurately, and provide higher accuracies than the traditional time-domain and frequency-domain features, wavelet packet node energy or two-direction 2D linear discriminant analysis based features of the same TFRs in most cases.

  10. The rare earth element potential of kaolin deposits in the Bohemian Massif (Czech Republic, Austria)

    NASA Astrophysics Data System (ADS)

    Höhn, S.; Frimmel, H. E.; Pašava, J.

    2014-12-01

    Four kaolin deposits in the Bohemian Massif were studied in order to assess the potential for the recovery of rare earth elements (REE) as by-products from the residue after extraction and refining of the raw kaolin. The behaviour of REE + Y during kaolinitization was found to be largely a function of pre-alteration mineralogy. In the examples studied, i.e. granite-derived deposits of Kriechbaum (Austria) and Božičany, and arkose-derived deposits of Kaznějov and Podbořany (all Czech Republic), the REE + Y are predominantly hosted by monazite which has remained unaffected by kaolinitization. The overall REE + Y content of the variably kaolinitized rocks is strongly dependent on their genesis. While ion adsorption plays only a minor role in the concentration of REE + Y in the studied kaolinitized rocks, the processing and refining of the raw kaolin leads to residues that are enriched in REE + Y by a factor of up to 40. The use of a magnetic separator and a hydrocyclone in the processing of the raw material can yield REE + Y contents of as much as 0.77 wt%. Although this value compares well with the REE + Y concentration in some potentially economic REE + Y projects elsewhere, the overall tonnage of the (REE + Y)-enriched residue is by far not sufficient to consider economic extraction of REE + Y as by-product. Our results are most probably applicable also to other kaolin deposits derived from the weathering of Hercynian basement granites elsewhere (e.g. in Saxonia and Bavaria, Germany). Overall, the potential for REE + Y production as by-product from kaolin mining has to be regarded as minimal.

  11. Distribution of potentially hazardous trace elements in coals from Shanxi province, China

    USGS Publications Warehouse

    Zhang, J.Y.; Zheng, C.G.; Ren, D.Y.; Chou, C.-L.; Liu, J.; Zeng, R.-S.; Wang, Z.P.; Zhao, F.H.; Ge, Y.T.

    2004-01-01

    Shanxi province, located in the center of China, is the biggest coal base of China. There are five coal-forming periods in Shanxi province: Late Carboniferous (Taiyuan Formation), Early Permian (Shanxi Formation), Middle Jurassic (Datong Formation), Tertiary (Taxigou Formation), and Quaternary. Hundred and ten coal samples and a peat sample from Shanxi province were collected and the contents of 20 potentially hazardous trace elements (PHTEs) (As, B, Ba, Cd, Cl, Co, Cr, Cu, F, Hg, Mn, Mo, Ni, Pb, Sb, Se, Th, U, V and Zn) in these samples were determined by instrumental neutron activation analysis, atomic absorption spectrometry, cold-vapor atomic absorption spectrometry, ion chromatography spectrometry, and wet chemical analysis. The result shows that the brown coals are enriched in As, Ba, Cd, Cr, Cu, F and Zn compared with the bituminous coals and anthracite, whereas the bituminous coals are enriched in B, Cl, Hg, and the anthracite is enriched in Cl, Hg, U and V. A comparison with world averages and crustal abundances (Clarke values) shows that the Quaternary peat is highly enriched in As and Mo, Tertiary brown coals are highly enriched in Cd, Middle Jurassic coals, Early Permian coals and Late Carboniferous coals are enriched in Hg. According to the coal ranks, the bituminous coals are highly enriched in Hg, whereas Cd, F and Th show low enrichments, and the anthracite is also highly enriched in Hg and low enrichment in Th. The concentrations of Cd, F, Hg and Th in Shanxi coals are more than world arithmetic means of concentrations for the corresponding elements. Comparing with the United States coals, Shanxi coals show higher concentrations of Cd, Hg, Pb, Se and Th. Most of Shanxi coals contain lower concentrations of PHTEs. ?? 2004 Elsevier Ltd. All rights reserved.

  12. Relations between matrix elements of different weak interactions and interpretation of the parity-nonconserving and electron electric-dipole-moment measurements in atoms and molecules

    SciTech Connect

    Dzuba, V. A.; Flambaum, V. V.; Harabati, C.

    2011-11-15

    The relations between matrix elements of different (P,T)-odd weak interactions are derived. We demonstrate that similar relations hold for parity-nonconserving transition amplitudes and electron electric dipole moments (EDMs) of atoms and molecules. This allows one to express P- and T-odd effects in many-electron systems caused by different symmetry-breaking mechanisms via each other using simple analytical formulas. We use these relations for the interpretation of the anapole moment measurements in cesium and thallium and for the analysis of the relative contributions of the scalar-pseudoscalar CP-odd weak interaction and electron EDMs to the EDMs of Cs, Tl, Fr, and other atoms and many polar molecules (YbF, PbO, ThO, etc.). Model-independent limits on electron EDMs and the parameter of the scalar-pseudoscalar CP-odd interaction are found from the analysis of the EDM measurements for Tl and YbF.

  13. NUMEN Project @ LNS : Heavy Ions Double Charge Exchange as a tool towards the 0νββ Nuclear Matrix Element

    NASA Astrophysics Data System (ADS)

    Agodi, C.; Cappuzzello, F.; Bonanno, D. L.; Bongiovanni, D. G.; Branchina, V.; Calabrese, S.; Calabretta, L.; Calanna, A.; Carbone, D.; Cavallaro, M.; Colonna, M.; Foti, A.; Finocchiaro, P.; Greco, V.; Lanzalone, G.; Lo Presti, D.; Longhitano, F.; Muoio, A.; Pandola, L.; Rifuggiato, D.; Tudisco, S.

    2016-06-01

    The NUMEN Project, proposed at INFN Laboratori Nazionali del Sud (LNS) in Catania, has the aim to access the nuclear matrix elements, entering the expression of the life time of double beta decay, by relevant cross sections of double charge exchange reactions. The basic point, on which it is based this innovative technique, is the coincidence of the initial and final state wave-functions in the two classes of processes and the similarity of the transition operators. A key aspect of the Project is the use of MAGNEX large acceptance magnetic spectrometer, for the detection of the ejectiles, and of the INFN LNS K800 Superconducting Cyclotron (CS), for the acceleration of the required high resolution and low emittance heavy-ion beams.

  14. Finite-volume corrections to the CP-odd nucleon matrix elements of the electromagnetic current from the QCD vacuum angle

    NASA Astrophysics Data System (ADS)

    Akan, Tarik; Guo, Feng-Kun; Meißner, Ulf-G.

    2014-09-01

    Nucleon electric dipole moments originating from strong CP-violation are being calculated by several groups using lattice QCD. We revisit the finite volume corrections to the CP-odd nucleon matrix elements of the electromagnetic current, which can be related to the electric dipole moments in the continuum, in the framework of chiral perturbation theory up to next-to-leading order taking into account the breaking of Lorentz symmetry. A chiral extrapolation of the recent lattice results of both the neutron and proton electric dipole moments is performed, which results in dn=(-2.7±1.2)×10-16eθ0 cm and dp=(2.1±1.2)×10-16eθ0 cm.

  15. Top Quark Mass Measurement in the lepton+jets Channel Using a Matrix Element Method and in situ Jet Energy Calibration

    SciTech Connect

    Aaltonen, T.; Brucken, E.; Devoto, F.; Mehtala, P.; Orava, R.; Alvarez Gonzalez, B.; Casal, B.; Gomez, G.; Palencia, E.; Rodrigo, T.; Ruiz, A.; Scodellaro, L.; Vila, I.; Vilar, R.; Amerio, S.; Dorigo, T.; Gresele, A.; Lazzizzera, I.; Amidei, D.; Campbell, M.

    2010-12-17

    A precision measurement of the top quark mass m{sub t} is obtained using a sample of tt events from pp collisions at the Fermilab Tevatron with the CDF II detector. Selected events require an electron or muon, large missing transverse energy, and exactly four high-energy jets, at least one of which is tagged as coming from a b quark. A likelihood is calculated using a matrix element method with quasi-Monte Carlo integration taking into account finite detector resolution and jet mass effects. The event likelihood is a function of m{sub t} and a parameter {Delta}{sub JES} used to calibrate the jet energy scale in situ. Using a total of 1087 events in 5.6 fb{sup -1} of integrated luminosity, a value of m{sub t}=173.0{+-}1.2 GeV/c{sup 2} is measured.

  16. Top Quark Mass Measurement in the lepton+jets Channel Using a Matrix Element Method and in situ Jet Energy Calibration

    NASA Astrophysics Data System (ADS)

    Aaltonen, T.; Álvarez González, B.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A.; Antos, J.; Apollinari, G.; Appel, J. A.; Apresyan, A.; Arisawa, T.; Artikov, A.; Asaadi, J.; Ashmanskas, W.; Auerbach, B.; Aurisano, A.; Azfar, F.; Badgett, W.; Barbaro-Galtieri, A.; Barnes, V. E.; Barnett, B. A.; Barria, P.; Bartos, P.; Bauce, M.; Bauer, G.; Bedeschi, F.; Beecher, D.; Behari, S.; Bellettini, G.; Bellinger, J.; Benjamin, D.; Beretvas, A.; Bhatti, A.; Binkley, M.; Bisello, D.; Bizjak, I.; Bland, K. R.; Blumenfeld, B.; Bocci, A.; Bodek, A.; Bortoletto, D.; Boudreau, J.; Boveia, A.; Brau, B.; Brigliadori, L.; Brisuda, A.; Bromberg, C.; Brucken, E.; Bucciantonio, M.; Budagov, J.; Budd, H. S.; Budd, S.; Burkett, K.; Busetto, G.; Bussey, P.; Buzatu, A.; Calancha, C.; Camarda, S.; Campanelli, M.; Campbell, M.; Canelli, F.; Canepa, A.; Carls, B.; Carlsmith, D.; Carosi, R.; Carrillo, S.; Carron, S.; Casal, B.; Casarsa, M.; Castro, A.; Catastini, P.; Cauz, D.; Cavaliere, V.; Cavalli-Sforza, M.; Cerri, A.; Cerrito, L.; Chen, Y. C.; Chertok, M.; Chiarelli, G.; Chlachidze, G.; Chlebana, F.; Cho, K.; Chokheli, D.; Chou, J. P.; Chung, W. H.; Chung, Y. S.; Ciobanu, C. I.; Ciocci, M. A.; Clark, A.; Compostella, G.; Convery, M. E.; Conway, J.; Corbo, M.; Cordelli, M.; Cox, C. A.; Cox, D. J.; Crescioli, F.; Cuenca Almenar, C.; Cuevas, J.; Culbertson, R.; Dagenhart, D.; D'Ascenzo, N.; Datta, M.; de Barbaro, P.; de Cecco, S.; de Lorenzo, G.; Dell'Orso, M.; Deluca, C.; Demortier, L.; Deng, J.; Deninno, M.; Devoto, F.; D'Errico, M.; di Canto, A.; di Ruzza, B.; Dittmann, J. R.; D'Onofrio, M.; Donati, S.; Dong, P.; Dorigo, T.; Ebina, K.; Elagin, A.; Eppig, A.; Erbacher, R.; Errede, D.; Errede, S.; Ershaidat, N.; Eusebi, R.; Fang, H. C.; Farrington, S.; Feindt, M.; Fernandez, J. P.; Ferrazza, C.; Field, R.; Flanagan, G.; Forrest, R.; Frank, M. J.; Franklin, M.; Freeman, J. C.; Furic, I.; Gallinaro, M.; Galyardt, J.; Garcia, J. E.; Garfinkel, A. F.; Garosi, P.; Gerberich, H.; Gerchtein, E.; Giagu, S.; Giakoumopoulou, V.; Giannetti, P.; Gibson, K.; Ginsburg, C. M.; Giokaris, N.; Giromini, P.; Giunta, M.; Giurgiu, G.; Glagolev, V.; Glenzinski, D.; Gold, M.; Goldin, D.; Goldschmidt, N.; Golossanov, A.; Gomez, G.; Gomez-Ceballos, G.; Goncharov, M.; González, O.; Gorelov, I.; Goshaw, A. T.; Goulianos, K.; Gresele, A.; Grinstein, S.; Grosso-Pilcher, C.; Group, R. C.; Guimaraes da Costa, J.; Gunay-Unalan, Z.; Haber, C.; Hahn, S. R.; Halkiadakis, E.; Hamaguchi, A.; Han, J. Y.; Happacher, F.; Hara, K.; Hare, D.; Hare, M.; Harr, R. F.; Hatakeyama, K.; Hays, C.; Heck, M.; Heinrich, J.; Herndon, M.; Hewamanage, S.; Hidas, D.; Hocker, A.; Hopkins, W.; Horn, D.; Hou, S.; Hughes, R. E.; Hurwitz, M.; Husemann, U.; Hussain, N.; Hussein, M.; Huston, J.; Introzzi, G.; Iori, M.; Ivanov, A.; James, E.; Jang, D.; Jayatilaka, B.; Jeon, E. J.; Jha, M. K.; Jindariani, S.; Johnson, W.; Jones, M.; Joo, K. K.; Jun, S. Y.; Junk, T. R.; Kamon, T.; Karchin, P. E.; Kato, Y.; Ketchum, W.; Keung, J.; Khotilovich, V.; Kilminster, B.; Kim, D. H.; Kim, H. S.; Kim, H. W.; Kim, J. E.; Kim, M. J.; Kim, S. B.; Kim, S. H.; Kim, Y. K.; Kimura, N.; Kirby, M.; Klimenko, S.; Kondo, K.; Kong, D. J.; Konigsberg, J.; Kotwal, A. V.; Kreps, M.; Kroll, J.; Krop, D.; Krumnack, N.; Kruse, M.; Krutelyov, V.; Kuhr, T.; Kurata, M.; Kwang, S.; Laasanen, A. T.; Lami, S.; Lammel, S.; Lancaster, M.; Lander, R. L.; Lannon, K.; Lath, A.; Latino, G.; Lazzizzera, I.; Lecompte, T.; Lee, E.; Lee, H. S.; Lee, J. S.; Lee, S. W.; Leo, S.; Leone, S.; Lewis, J. D.; Lin, C.-J.; Linacre, J.; Lindgren, M.; Lipeles, E.; Lister, A.; Litvintsev, D. O.; Liu, C.; Liu, Q.; Liu, T.; Lockwitz, S.; Lockyer, N. S.; Loginov, A.; Lucchesi, D.; Lueck, J.; Lujan, P.; Lukens, P.; Lungu, G.; Lys, J.; Lysak, R.; Madrak, R.; Maeshima, K.; Makhoul, K.; Maksimovic, P.; Malik, S.; Manca, G.; Manousakis-Katsikakis, A.; Margaroli, F.; Marino, C.; Martínez, M.; Martínez-Ballarín, R.; Mastrandrea, P.; Mathis, M.; Mattson, M. E.; Mazzanti, P.; McFarland, K. S.; McIntyre, P.; McNulty, R.; Mehta, A.; Mehtala, P.; Menzione, A.; Mesropian, C.; Miao, T.; Mietlicki, D.; Mitra, A.; Miyake, H.; Moed, S.; Moggi, N.; Mondragon, M. N.; Moon, C. S.; Moore, R.; Morello, M. J.; Morlock, J.; Movilla Fernandez, P.; Mukherjee, A.; Muller, Th.; Murat, P.; Mussini, M.; Nachtman, J.; Nagai, Y.; Naganoma, J.; Nakano, I.; Napier, A.; Nett, J.; Neu, C.; Neubauer, M. S.; Nielsen, J.; Nodulman, L.; Norniella, O.; Nurse, E.; Oakes, L.; Oh, S. H.; Oh, Y. D.; Oksuzian, I.; Okusawa, T.; Orava, R.; Ortolan, L.; Pagan Griso, S.; Pagliarone, C.; Palencia, E.; Papadimitriou, V.; Paramonov, A. A.; Patrick, J.; Pauletta, G.; Paulini, M.; Paus, C.; Pellett, D. E.; Penzo, A.; Phillips, T. J.; Piacentino, G.; Pianori, E.; Pilot, J.; Pitts, K.; Plager, C.; Pondrom, L.; Potamianos, K.; Poukhov, O.; Prokoshin, F.; Pronko, A.; Ptohos, F.; Pueschel, E.; Punzi, G.; Pursley, J.; Rahaman, A.; Ramakrishnan, V.; Ranjan, N.; Redondo, I.; Renton, P.; Rescigno, M.; Rimondi, F.; Ristori, L.; Robson, A.; Rodrigo, T.; Rodriguez, T.; Rogers, E.; Rolli, S.; Roser, R.; Rossi, M.; Rubbo, F.; Ruffini, F.; Ruiz, A.; Russ, J.; Rusu, V.; Safonov, A.; Sakumoto, W. K.; Santi, L.; Sartori, L.; Sato, K.; Saveliev, V.; Savoy-Navarro, A.; Schlabach, P.; Schmidt, A.; Schmidt, E. E.; Schmidt, M. P.; Schmitt, M.; Schwarz, T.; Scodellaro, L.; Scribano, A.; Scuri, F.; Sedov, A.; Seidel, S.; Seiya, Y.; Semenov, A.; Sforza, F.; Sfyrla, A.; Shalhout, S. Z.; Shears, T.; Shepard, P. F.; Shimojima, M.; Shiraishi, S.; Shochet, M.; Shreyber, I.; Siegrist, J.; Simonenko, A.; Sinervo, P.; Sissakian, A.; Sliwa, K.; Smith, J. R.; Snider, F. D.; Soha, A.; Somalwar, S.; Sorin, V.; Squillacioti, P.; Stanitzki, M.; Denis, R. St.; Stelzer, B.; Stelzer-Chilton, O.; Stentz, D.; Strologas, J.; Strycker, G. L.; Sudo, Y.; Sukhanov, A.; Suslov, I.; Takemasa, K.; Takeuchi, Y.; Tang, J.; Tecchio, M.; Teng, P. K.; Thom, J.; Thome, J.; Thompson, G. A.; Thomson, E.; Ttito-Guzmán, P.; Tkaczyk, S.; Toback, D.; Tokar, S.; Tollefson, K.; Tomura, T.; Tonelli, D.; Torre, S.; Torretta, D.; Totaro, P.; Trovato, M.; Tu, Y.; Turini, N.; Ukegawa, F.; Uozumi, S.; Varganov, A.; Vataga, E.; Vázquez, F.; Velev, G.; Vellidis, C.; Vidal, M.; Vila, I.; Vilar, R.; Volobouev, I.; Vogel, M.; Volpi, G.; Wagner, P.; Wagner, R. L.; Wakisaka, T.; Wallny, R.; Wang, S. M.; Warburton, A.; Waters, D.; Weinberger, M.; Wester, W. C., III; Whitehouse, B.; Whiteson, D.; Wicklund, A. B.; Wicklund, E.; Wilbur, S.; Wick, F.; Williams, H. H.; Wilson, J. S.; Wilson, P.; Winer, B. L.; Wittich, P.; Wolbers, S.; Wolfe, H.; Wright, T.; Wu, X.; Wu, Z.; Yamamoto, K.; Yamaoka, J.; Yang, T.; Yang, U. K.; Yang, Y. C.; Yao, W.-M.; Yeh, G. P.; Yi, K.; Yoh, J.; Yorita, K.; Yoshida, T.; Yu, G. B.; Yu, I.; Yu, S. S.; Yun, J. C.; Zanetti, A.; Zeng, Y.; Zucchelli, S.

    2010-12-01

    A precision measurement of the top quark mass mt is obtained using a sample of tt¯ events from pp¯ collisions at the Fermilab Tevatron with the CDF II detector. Selected events require an electron or muon, large missing transverse energy, and exactly four high-energy jets, at least one of which is tagged as coming from a b quark. A likelihood is calculated using a matrix element method with quasi-Monte Carlo integration taking into account finite detector resolution and jet mass effects. The event likelihood is a function of mt and a parameter ΔJES used to calibrate the jet energy scale in situ. Using a total of 1087 events in 5.6fb-1 of integrated luminosity, a value of mt=173.0±1.2GeV/c2 is measured.

  17. Constraint on 0νββ matrix elements from a novel decay channel of the scissors mode: the case of 154Gd.

    PubMed

    Beller, J; Pietralla, N; Barea, J; Elvers, M; Endres, J; Fransen, C; Kotila, J; Möller, O; Richter, A; Rodríguez, T R; Romig, C; Savran, D; Scheck, M; Schnorrenberger, L; Sonnabend, K; Werner, V; Zilges, A; Zweidinger, M

    2013-10-25

    The nucleus (154)Gd is located in a region of the nuclear chart where rapid changes of nuclear deformation occur as a function of particle number. It was investigated using a combination of γ-ray scattering experiments and a γγ-coincidence study following electron capture decay of (154)Tb(m). A novel decay channel from the scissors mode to the first excited 0(+) state was observed. Its transition strength was determined to B(M1;1(sc)(+)→0(2)(+))=0.031(4)μ(N)(2). The properties of the scissors mode of (154)Gd imply a much larger matrix element than previously thought for the neutrinoless double-β decay to the 0(2)(+) state in such a shape-transitional region. Theory indicates an even larger effect for (150)Nd.

  18. First-order nonadiabatic coupling matrix elements between excited states: A Lagrangian formulation at the CIS, RPA, TD-HF, and TD-DFT levels

    SciTech Connect

    Li, Zhendong; Liu, Wenjian

    2014-07-07

    Analytic expressions for the first-order nonadiabatic coupling matrix elements between electronically excited states are first formulated exactly via both time-independent equation of motion and time-dependent response theory, and are then approximated at the configuration interaction singles, particle-hole/particle-particle random phase approximation, and time-dependent density functional theory/Hartree-Fock levels of theory. Note that, to get the Pulay terms arising from the derivatives of basis functions, the standard response theory designed for electronic perturbations has to be extended to nuclear derivatives. The results are further recast into a Lagrangian form that is similar to that for excited-state energy gradients and allows to use atomic orbital based direct algorithms for large molecules.

  19. Top Quark Mass Measurement in the Lepton + Jets Channel Using a Matrix Element Method and \\textit{in situ} Jet Energy Calibration

    SciTech Connect

    Aaltonen, T.; Alvarez Gonzalez, B.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A.; Antos, J.; Apollinari, G.; Appel, J.A.; Apresyan, A.; Arisawa, T.; /Waseda U. /Dubna, JINR

    2010-10-01

    A precision measurement of the top quark mass m{sub t} is obtained using a sample of t{bar t} events from p{bar p} collisions at the Fermilab Tevatron with the CDF II detector. Selected events require an electron or muon, large missing transverse energy, and exactly four high-energy jets, at least one of which is tagged as coming from a b quark. A likelihood is calculated using a matrix element method with quasi-Monte Carlo integration taking into account finite detector resolution and jet mass effects. The event likelihood is a function of m{sub t} and a parameter {Delta}{sub JES} used to calibrate the jet energy scale in situ. Using a total of 1087 events, a value of m{sub t} = 173.0 {+-} 1.2 GeV/c{sup 2} is measured.

  20. Potentially toxic element contamination in soil and accumulation in maize plants in a smelter area in Kosovo.

    PubMed

    Nannoni, Francesco; Rossi, Sara; Protano, Giuseppe

    2016-06-01

    A biogeochemical field study was carried out in the industrial area of Kosovska Mitrovica in northern Kosovo, where agricultural soils were contaminated by potentially toxic elements due to smelting activity. Total and bioavailable contents of As, Cd, Co, Cu, Pb, Sb, U and Zn in soil and their concentrations in maize roots and grains were determined. Soil contamination by As, Cd, Cu, Pb, Sb and Zn was variable from slightly to highly contaminated soils and influenced both the bioavailable fraction and accumulation of these potentially toxic elements in maize tissues. The comparison between potentially toxic element concentrations in roots and grains indicated that maize is able to limit the transfer of non-essential elements to edible parts. The plant-to-soil bioconcentration indices suggested that the transfer of potentially toxic elements from soil to plant was predicted better by bioavailable concentrations than by the total contents. These indices further identified some competitions and interactions among these elements in root uptake and root-to-grain translocation. PMID:26961525

  1. Marine phosphorites as potential resources for heavy rare earth elements and yttrium

    USGS Publications Warehouse

    Hein, James; Koschinsky, Andrea; Mikesell, Mariah; Mizell, Kira; Glenn, Craig R.; Wood, Ray

    2016-01-01

    Marine phosphorites are known to concentrate rare earth elements and yttrium (REY) during early diagenetic formation. Much of the REY data available are decades old and incomplete, and there has not been a systematic study of REY distributions in marine phosphorite deposits that formed over a range of oceanic environments. Consequently, we initiated this study to determine if marine phosphorite deposits found in the global ocean host REY concentrations of high enough grade to be of economic interest. This paper addresses continental-margin (CM) and open-ocean seamount phosphorites. All 75 samples analyzed are composed predominantly of carbonate fluorapatite and minor detrital and authigenic minerals. CM phosphorites have low total REY contents (mean 161 ppm) and high heavy REY (HREY) complements (mean 49%), while seamount phosphorites have 4–6 times higher individual REY contents (except for Ce, which is subequal; mean ΣREY 727 ppm), and very high HREY complements (mean 60%). The predominant causes of higher concentrations and larger HREY complements in seamount phosphorites compared to CM phosphorites are age, changes in seawater REY concentrations over time, water depth of formation, changes in pH and complexing ligands, and differences in organic carbon content in the depositional environments. Potential ore deposits with high HREY complements, like the marine phosphorites analyzed here, could help supply the HREY needed for high-tech and green-tech applications without creating an oversupply of the LREY.

  2. Potential of minicomputer/array-processor system for nonlinear finite-element analysis

    NASA Technical Reports Server (NTRS)

    Strohkorb, G. A.; Noor, A. K.

    1983-01-01

    The potential of using a minicomputer/array-processor system for the efficient solution of large-scale, nonlinear, finite-element problems is studied. A Prime 750 is used as the host computer, and a software simulator residing on the Prime is employed to assess the performance of the Floating Point Systems AP-120B array processor. Major hardware characteristics of the system such as virtual memory and parallel and pipeline processing are reviewed, and the interplay between various hardware components is examined. Effective use of the minicomputer/array-processor system for nonlinear analysis requires the following: (1) proper selection of the computational procedure and the capability to vectorize the numerical algorithms; (2) reduction of input-output operations; and (3) overlapping host and array-processor operations. A detailed discussion is given of techniques to accomplish each of these tasks. Two benchmark problems with 1715 and 3230 degrees of freedom, respectively, are selected to measure the anticipated gain in speed obtained by using the proposed algorithms on the array processor.

  3. Bioconcentration factors and the risk concentrations of potentially toxic elements in garden soils.

    PubMed

    Boim, Alexys Giorgia Friol; Melo, Leônidas Carrijo Azevedo; Moreno, Fabio Netto; Alleoni, Luís Reynaldo Ferracciú

    2016-04-01

    Empirical models describe soil-plant transfers to explain the variations in the occurrence of potentially toxic elements (PTE) in soils and to estimate the Bioconcentration Factor (BCF). In this study, results were selected based on data in the literature on soils of humid tropical and temperate regions to evaluate soil-plant transfer models, to calculate the BCF and to derive risk concentrations of Cu, Cr, Pb, Ni and Zn present in the exposure pathway leading to the consumption of contaminated vegetables. The Cetesb (Environmental Agency of the State of Sao Paulo, Brazil) mathematical model was used to derive the risk posed by soil concentrations in urban and rural exposure scenarios. The results of the pseudo total contents of PTE in the soil and the contents absorbed by plants were compared and the BCFs were calculated by the use of geometric means, including a correction factor appropriate to each particular type of soil. Differences were observed between BCFs calculated for each climate region: humid tropical (HTR) and temperate (TE), which the first one presented the highest values to BCF in leaves and the lowest BCF values for root, except Ni, compared to second one. The soil concentrations with the highest risk were found in humid tropical regions as compared with those found in temperate regions, except for Ni. The obtained BCFs may contribute to any future revisions of guideline values as well as help other state environmental agencies to establish their own guideline values.

  4. A fault diagnosis scheme of rolling element bearing based on near-field acoustic holography and gray level co-occurrence matrix

    NASA Astrophysics Data System (ADS)

    Lu, Wenbo; Jiang, Weikang; Wu, Haijun; Hou, Junjian

    2012-07-01

    Vibration signal analysis is the most widely used technique in condition monitoring or fault diagnosis, whereas in some cases vibration-based diagnosis is restrained because of its contact measurement. Acoustic-based diagnosis (ABD) with non-contact measurement has received little attention, although sound field may contain abundant information related to fault pattern. A new scheme of ABD for rolling element bearing fault diagnosis based on near-field acoustic holography (NAH) and gray level co-occurrence matrix (GLCM) is presented in this paper. It focuses on applying the distribution information of sound field to bearing fault diagnosis. A series of rolling element bearings with different types of fault are experimentally studied. Sound fields and corresponding acoustic images in different bearing conditions are obtained by fast Fourier transform (FFT) based NAH. GLCM features are extracted for capturing fault pattern information underlying sound fields. The optimal feature subset selected by improved F-score is fed into multi-class support vector machine (SVM) for fault pattern identification. The feasibility and effectiveness of our proposed scheme is demonstrated on the good experimental results and the comparison with the traditional ABD method. Considering test cost, the quantized level and the number of GLCM features for each characteristic frequency is suggested to be 4 and 32, respectively, with the satisfactory accuracy rate 97.5%.

  5. Reduction of Matrix-Induced Oxide Interferences on Rare Earth Elements and Platinum Using a Desolvating Nebulizer System with Quadrupole Inductively Coupled Plasma Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Smith, F.

    2013-12-01

    This paper will examine the use of a specialized low-flow desolvating nebulizer system for reduction of oxide mass spectral interferences that can occur in quadrupole inductively coupled plasma mass spectrometry (Q-ICP-MS). This nebulizer system uses an inert low-flow nebulizer (100 microliters/min) coupled to an inert, heated membrane desolvator for efficient water vapor removal before sample aerosol injection to the Q-ICP-MS instrument. Water vapor from conventional nebulizer / spray chamber systems used with Q-ICP-MS can cause numerous mass spectral interferences. One general example is metal oxides formed from the combination of oxygen (from injected water) with sample matrix components. Two specific examples of metal oxide interferences will be investigated with and without membrane desolvation: Ba and Ce oxides on several low-mass rare earth elements (Sm, Eu, and Gd) and Hf oxides on platinum. Rare earth elements are critically important components of modern electronics (ex. magnets, lasers, cell phones, computers) and platinum is a widely used catalyst. Figures of merit for both a conventional nebulizer/spray chamber and the desolvating nebulizer systems will include operating conditions, interference intensities and reduction factors, background equivalent concentrations (BECs), and instrument detection limits (IDLs).

  6. Determination of elemental constituents in different matrix materials and flow injection studies by the electrolyte cathode glow discharge technique with a new design

    SciTech Connect

    Shekhar, R.; Karunasagar, D.; Ranjit, M.; Arunachalam, J.

    2009-10-15

    An open-to-air type electrolyte cathode discharge (ELCAD) has been developed with a new design. The present configuration leads to a stable plasma even at low flow rates (0.96 mL/min). Plasma fluctuations arising from the variations in the gap between solid anode and liquid cathode were eliminated by providing a V-groove to the liquid glass-capillary. Cathode (ground) connection is given to the solution at the V-groove itself. Interfaced to atomic emission spectrometry (AES), its analytical performance is evaluated. The optimized molarity of the solution is 0.2 M. The analytical response curves for Ca, Cu, Cd, Pb, Hg, Fe, and Zn demonstrated good linearity. The limit of detections of Ca, Cu, Cd, Pb, Hg, Fe, and Zn are determined to be 17, 11, 5, 45, 15, 28, and 3 ng mL{sup -1}. At an integration time of 0.3 s, the relative standard deviation (RSD) values of the acid blank solutions are found to be less than 10% for the elements Ca, Cu, Cd, Hg, Fe, and Zn and 18% for Pb. The method is applied for the determination of the elemental constituents in different matrix materials such as tuna fish (IAEA-350), oyster tissue (NIST SRM 1566a), and coal fly ash (CFA SRM 1633b). The obtained results are in good agreement with the certified values. The accuracy is found to be between 7% and 0.6% for major to trace levels of constituent elements and the precision between 11% and 0.6%. For the injection of 100 {mu} L of 200 ng mL{sup -1} mercury solution at the flow rate of 0.8 mL/min, the flow injection studies resulted in the relative standard deviation (RSD) of 8%, concentration detection limit of 10 ng/mL, and mass detection limit of 1 ng for mercury.

  7. Determination of elemental constituents in different matrix materials and flow injection studies by the electrolyte cathode glow discharge technique with a new design.

    PubMed

    Shekhar, R; Karunasagar, D; Ranjit, Manjusha; Arunachalam, J

    2009-10-01

    An open-to-air type electrolyte cathode discharge (ELCAD) has been developed with a new design. The present configuration leads to a stable plasma even at low flow rates (0.96 mL/min). Plasma fluctuations arising from the variations in the gap between solid anode and liquid cathode were eliminated by providing a V-groove to the liquid glass-capillary. Cathode (ground) connection is given to the solution at the V-groove itself. Interfaced to atomic emission spectrometry (AES), its analytical performance is evaluated. The optimized molarity of the solution is 0.2 M. The analytical response curves for Ca, Cu, Cd, Pb, Hg, Fe, and Zn demonstrated good linearity. The limit of detections of Ca, Cu, Cd, Pb, Hg, Fe, and Zn are determined to be 17, 11, 5, 45, 15, 28, and 3 ng mL(-1). At an integration time of 0.3 s, the relative standard deviation (RSD) values of the acid blank solutions are found to be less than 10% for the elements Ca, Cu, Cd, Hg, Fe, and Zn and 18% for Pb. The method is applied for the determination of the elemental constituents in different matrix materials such as tuna fish (IAEA-350), oyster tissue (NIST SRM 1566a), and coal fly ash (CFA SRM 1633b). The obtained results are in good agreement with the certified values. The accuracy is found to be between 7% and 0.6% for major to trace levels of constituent elements and the precision between 11% and 0.6%. For the injection of 100 microL of 200 ng mL(-1) mercury solution at the flow rate of 0.8 mL/min, the flow injection studies resulted in the relative standard deviation (RSD) of 8%, concentration detection limit of 10 ng/mL, and mass detection limit of 1 ng for mercury. PMID:19715301

  8. Predictions of thermal buckling strengths of hypersonic aircraft sandwich panels using minimum potential energy and finite element methods

    NASA Technical Reports Server (NTRS)

    Ko, William L.

    1995-01-01

    Thermal buckling characteristics of hypersonic aircraft sandwich panels of various aspect ratios were investigated. The panel is fastened at its four edges to the substructures under four different edge conditions and is subjected to uniform temperature loading. Minimum potential energy theory and finite element methods were used to calculate the panel buckling temperatures. The two methods gave fairly close buckling temperatures. However, the finite element method gave slightly lower buckling temperatures than those given by the minimum potential energy theory. The reasons for this slight discrepancy in eigensolutions are discussed in detail. In addition, the effect of eigenshifting on the eigenvalue convergence rate is discussed.

  9. Predictions of thermal buckling strengths of hypersonic aircraft sandwich panels using minimum potential energy and finite element methods

    NASA Astrophysics Data System (ADS)

    Ko, William L.

    1995-05-01

    Thermal buckling characteristics of hypersonic aircraft sandwich panels of various aspect ratios were investigated. The panel is fastened at its four edges to the substructures under four different edge conditions and is subjected to uniform temperature loading. Minimum potential energy theory and finite element methods were used to calculate the panel buckling temperatures. The two methods gave fairly close buckling temperatures. However, the finite element method gave slightly lower buckling temperatures than those given by the minimum potential energy theory. The reasons for this slight discrepancy in eigensolutions are discussed in detail. In addition, the effect of eigenshifting on the eigenvalue convergence rate is discussed.

  10. Differential cross sections, charge production asymmetry, and spin-density matrix elements for D ∗±(2010) produced in 500 GeV/ cπ--nucleon interactions

    NASA Astrophysics Data System (ADS)

    Aitala, E. M.; Amato, S.; Anjos, J. C.; Appel, J. A.; Ashery, D.; Banerjee, S.; Bediaga, I.; Blaylock, G.; Bracker, S. B.; Burchat, P. R.; Burnstein, R. A.; Carter, T.; Carvalho, H. S.; Copty, N. K.; Cremaldi, L. M.; Darling, C.; Denisenko, K.; Devmal, S.; Fernandez, A.; Fox, G. F.; Gagnon, P.; Gobel, C.; Gounder, K.; Halling, A. M.; Herrera, G.; Hurvits, G.; James, C.; Kasper, P. A.; Kwan, S.; Langs, D. C.; Leslie, J.; Lundberg, B.; Magnin, J.; Massafferri, A.; MayTal-Beck, S.; Meadows, B.; de Mello Neto, J. R. T.; Mihalcea, D.; Milburn, R. H.; de Miranda, J. M.; Napier, A.; Nguyen, A.; d'Oliveira, A. B.; O'Shaughnessy, K.; Peng, K. C.; Perera, L. P.; Purohit, M. V.; Quinn, B.; Radeztsky, S.; Rafatian, A.; Reay, N. W.; Reidy, J. J.; dos Reis, A. C.; Rubin, H. A.; Sanders, D. A.; Santha, A. K. S.; Santoro, A. F. S.; Schwartz, A. J.; Sheaff, M.; Sidwell, R. A.; Slaughter, A. J.; Sokoloff, M. D.; Solano Salinas, C. J.; Stanton, N. R.; Stefanski, R. J.; Stenson, K.; Summers, D. J.; Takach, S.; Thorne, K.; Tripathi, A. K.; Watanabe, S.; Weiss-Babai, R.; Wiener, J.; Witchey, N.; Wolin, E.; Yang, S. M.; Yi, D.; Yoshida, S.; Zaliznyak, R.; Zhang, C.; Fermilab E791 Collaboration

    2002-07-01

    We report differential cross sections for the production of D ∗±(2010) produced in 500 GeV/ cπ--nucleon interactions from experiment E791 at Fermilab, as functions of Feynman- x ( xF) and transverse momentum squared ( pT2). We also report the D ∗± charge asymmetry and spin-density matrix elements as functions of these variables. Investigation of the spin-density matrix elements shows no evidence of polarization. The average values of the spin alignment are < η>=0.01±0.02 and -0.01±0.02 for leading and non-leading particles, respectively.

  11. Fluid Shear Stress Regulates the Invasive Potential of Glioma Cells via Modulation of Migratory Activity and Matrix Metalloproteinase Expression

    PubMed Central

    Qazi, Henry; Shi, Zhong-Dong; Tarbell, John M.

    2011-01-01

    Background Glioma cells are exposed to elevated interstitial fluid flow during the onset of angiogenesis, at the tumor periphery while invading normal parenchyma, within white matter tracts, and during vascular normalization therapy. Glioma cell lines that have been exposed to fluid flow forces in vivo have much lower invasive potentials than in vitro cell motility assays without flow would indicate. Methodology/Principal Findings A 3D Modified Boyden chamber (Darcy flow through collagen/cell suspension) model was designed to mimic the fluid dynamic microenvironment to study the effects of fluid shear stress on the migratory activity of glioma cells. Novel methods for gel compaction and isolation of chemotactic migration from flow stimulation were utilized for three glioma cell lines: U87, CNS-1, and U251. All physiologic levels of fluid shear stress suppressed the migratory activity of U87 and CNS-1 cell lines. U251 motility remained unaltered within the 3D interstitial flow model. Matrix Metalloproteinase (MMP) inhibition experiments and assays demonstrated that the glioma cells depended on MMP activity to invade, and suppression in motility correlated with downregulation of MMP-1 and MMP-2 levels. This was confirmed by RT-PCR and with the aid of MMP-1 and MMP-2 shRNA constructs. Conclusions/Significance Fluid shear stress in the tumor microenvironment may explain reduced glioma invasion through modulation of cell motility and MMP levels. The flow-induced migration trends were consistent with reported invasive potentials of implanted gliomas. The models developed for this study imply that flow-modulated motility involves mechanotransduction of fluid shear stress affecting MMP activation and expression. These models should be useful for the continued study of interstitial flow effects on processes that affect tumor progression. PMID:21637818

  12. Long interspersed nuclear element-1 hypomethylation and oxidative stress: correlation and bladder cancer diagnostic potential.

    PubMed

    Patchsung, Maturada; Boonla, Chanchai; Amnattrakul, Passakorn; Dissayabutra, Thasinas; Mutirangura, Apiwat; Tosukhowong, Piyaratana

    2012-01-01

    Although, increased oxidative stress and hypomethylation of long interspersed nuclear element-1 (LINE-1) associate with bladder cancer (BCa) development, the relationship between these alterations is unknown. We evaluated the oxidative stress and hypomethylation of the LINE-1 in 61 BCa patients and 45 normal individuals. To measure the methylation levels and to differentiate the LINE-1 loci into hypermethylated, partially methylated and hypomethylated, peripheral blood cells, urinary exfoliated cells and cancerous tissues were evaluated by combined bisulfite restriction analysis PCR. The urinary total antioxidant status (TAS) and plasma protein carbonyl content were determined. The LINE-1 methylation levels and patterns, especially hypomethylated loci, in the blood and urine cells of the BCa patients were different from the levels and patterns in the healthy controls. The urinary TAS was decreased, whereas the plasma protein carbonyl content was increased in the BCa patients relative to the controls. A positive correlation between the methylation of LINE-1 in the blood-derived DNA and urinary TAS was found in both the BCa and control groups. The urinary hypomethylated LINE-1 loci and the plasma protein carbonyl content provided the best diagnostic potential for BCa prediction. Based on post-diagnostic samples, the combination test improved the diagnostic power to a sensitivity of 96% and a specificity of 96%. In conclusion, decreased LINE-1 methylation is associated with increased oxidative stress both in healthy and BCa subjects across the various tissue types, implying a dose-response association. Increases in the LINE-1 hypomethylation levels and the number of hypomethylated loci in both the blood- and urine-derived cells and increase in the oxidative stress were found in the BCa patients. The combination test of the urinary hypomethylated LINE-1 loci and the plasma protein carbonyl content may be useful for BCa screening and monitoring of treatment.

  13. Potential for improvement in high heat flux HyperVapotron element performance using nanofluids

    NASA Astrophysics Data System (ADS)

    Sergis, A.; Hardalupas, Y.; Barrett, T. R.

    2013-11-01

    HyperVapotron (HV) elements have been used extensively as high heat flux beam stopping components in nuclear fusion research facilities. These water-cooled heat exchangers use a boiling heat transfer mechanism and so are inherently limited by their critical heat flux (CHF). The use of a nanofluid as the coolant, instead of water, promises to enhance the heat transfer performance of the HV and increase the CHF by a factor of 2 or 3, which would lead to a step-change improvement in the power handling capability. This paper reports on computational and experimental analyses which have indicated mechanisms for the enhanced thermal performance of nanofluids. A molecular dynamics simulation code has been developed which has identified heat transfer augmentation mechanisms that depart from classical thermodynamics associated with the presence of nanoparticles. In addition, an experiment has been conducted which uses particle image velocimetry to measure the flow field in a full-scale HV. Past studies have yielded qualitative experimental results, but the measurements reported here provide quantitative data to aid the understanding of the initial flow field inside the HV (i.e., before a heat flux is applied). Further, the experiment is conducted using both water and Al2O3-water nanofluid as the flow medium. Thus, these velocity measurements offer a first indication for potentially enhanced heat transfer in HV devices when nanofluids are used as the coolant. The improved understanding of the HV flow regime and the cooling advantage of nanofluids could assist the design of advanced high heat flux components for future fusion machines.

  14. Modeling of the Through-the-Thickness Electric Potentials of a Piezoelectric Bimorph Using the Spectral Element Method

    PubMed Central

    Dong, Xingjian; Peng, Zhike; Hua, Hongxing; Meng, Guang

    2014-01-01

    An efficient spectral element (SE) with electric potential degrees of freedom (DOF) is proposed to investigate the static electromechanical responses of a piezoelectric bimorph for its actuator and sensor functions. A sublayer model based on the piecewise linear approximation for the electric potential is used to describe the nonlinear distribution of electric potential through the thickness of the piezoelectric layers. An equivalent single layer (ESL) model based on first-order shear deformation theory (FSDT) is used to describe the displacement field. The Legendre orthogonal polynomials of order 5 are used in the element interpolation functions. The validity and the capability of the present SE model for investigation of global and local responses of the piezoelectric bimorph are confirmed by comparing the present solutions with those obtained from coupled 3-D finite element (FE) analysis. It is shown that, without introducing any higher-order electric potential assumptions, the current method can accurately describe the distribution of the electric potential across the thickness even for a rather thick bimorph. It is revealed that the effect of electric potential is significant when the bimorph is used as sensor while the effect is insignificant when the bimorph is used as actuator, and therefore, the present study may provide a better understanding of the nonlinear induced electric potential for bimorph sensor and actuator. PMID:24561399

  15. The potential of asymmetric flow field-flow fractionation hyphenated to multiple detectors for the quantification and size estimation of silica nanoparticles in a food matrix.

    PubMed

    Heroult, Julien; Nischwitz, Volker; Bartczak, Dorota; Goenaga-Infante, Heidi

    2014-06-01

    This work represents a first systematic approach to the size-based elemental quantification and size estimation of metal(loid) oxide nanoparticles such as silica (SiO2) in a real food matrix using asymmetric flow field-flow fractionation coupled online with inductively coupled plasma mass spectrometry (ICP-MS) and multi-angle light scattering (MALS) and offline with transmission electron microscopy (TEM) with energy-dispersive X-ray analysis (EDAX). Coffee creamer was selected as the model sample since it is known to contain silica as well as metal oxides such as titania at the milligramme per kilogramme levels. Optimisation of sample preparation conditions such as matrix-to-solvent ratio, defatting with organic solvents and sonication time that may affect nanoparticle size and size distribution in suspensions was investigated. Special attention was paid to the selection of conditions that minimise particle transformation during sample preparation and analysis. The coffee creamer matrix components were found to stabilise food grade SiO2 particles in comparison with water suspensions whilst no significant effect of defatting using hexane was found. The use of sample preparation procedures that mimic food cooking in real life was also investigated regarding their effect on particle size and particle size distribution of silica nanoparticles in the investigated food matrix; no significant effect of the water temperature ranging from ambient temperature to 60 °C was observed. Field-flow fractionation coupled to inductively coupled plasma-mass spectrometry (FFF-ICP-MS) analysis of extracts of both unspiked coffee creamer and coffee creamer spiked with food grade silicon dioxide, using different approaches for size estimation, enabled determination of SiO2 size-based speciation. Element-specific detection by ICP-MS and post-FFF calibration with elemental calibration standards was used to determine the elemental composition of size fractions separated online by FFF

  16. Trace elements in scalp hair from potentially exposed individuals in the vicinity of the Bayan Obo mine in Baotou, China.

    PubMed

    Pan, Yuxue; Li, Haitao

    2015-11-01

    Mining activities including mineral excavation and ore transportation produce and release large amounts of pollutants to the surrounding environment, raising concerns regarding the effects of environmental exposure to pollutants on human health. The concentration of elements in hair can be used as a biomarker of exposure to chemical elements. In the present study, hair samples from 89 relatively healthy volunteers aged 11-77 years old (57 living near Bayan Obo giant REE-Nb-Fe ore deposit and 32 in non-mining areas) from Baotou (Inner Mongolia, China) were analyzed to determine the contents of 25 chemical elements (Ag, Al, As, Ba, Bi, Ca, Cd, Co, Cr, Cs, Cu, Fe, Ga, Li, Mg, Mn, Mo, Ni, Pb, Rb, Se, Tl, U, V and Zn) with the aim of gaining insights about the potential exposure to chemical elements of the population living within the Bayan Obo opencast mining area. The effects of gender and living area on element concentrations in hair were also investigated. The results showed that the mean concentrations of the target elements (Ag, Al, Ba, Cd, Co, Li, Mn, Ni, Pb, Tl, V, Cs, Ga, Rb, U, Bi, Mo, As, Ca, Fe, Mg and Zn) in human hair from the mining area (MA) were primarily higher than that in non-mining areas (NMA). The area of residence had an influence on the presence of select trace elements (As, Cd, Mg, Pb, Tl, U and Zn) in human hair. In addition, the hair samples from MA showed statistically significant differences between males and females for a larger number of elements than those in NMA in which only Ag, Bi and Se were significantly different. This result implies a potential influence of mining activities on residents living in the vicinity. These findings confirm the need for competent authorities to act as early as possible and to implement strategies aimed to protect exposed populations and the entire ecosystem.

  17. Trace elements in scalp hair from potentially exposed individuals in the vicinity of the Bayan Obo mine in Baotou, China.

    PubMed

    Pan, Yuxue; Li, Haitao

    2015-11-01

    Mining activities including mineral excavation and ore transportation produce and release large amounts of pollutants to the surrounding environment, raising concerns regarding the effects of environmental exposure to pollutants on human health. The concentration of elements in hair can be used as a biomarker of exposure to chemical elements. In the present study, hair samples from 89 relatively healthy volunteers aged 11-77 years old (57 living near Bayan Obo giant REE-Nb-Fe ore deposit and 32 in non-mining areas) from Baotou (Inner Mongolia, China) were analyzed to determine the contents of 25 chemical elements (Ag, Al, As, Ba, Bi, Ca, Cd, Co, Cr, Cs, Cu, Fe, Ga, Li, Mg, Mn, Mo, Ni, Pb, Rb, Se, Tl, U, V and Zn) with the aim of gaining insights about the potential exposure to chemical elements of the population living within the Bayan Obo opencast mining area. The effects of gender and living area on element concentrations in hair were also investigated. The results showed that the mean concentrations of the target elements (Ag, Al, Ba, Cd, Co, Li, Mn, Ni, Pb, Tl, V, Cs, Ga, Rb, U, Bi, Mo, As, Ca, Fe, Mg and Zn) in human hair from the mining area (MA) were primarily higher than that in non-mining areas (NMA). The area of residence had an influence on the presence of select trace elements (As, Cd, Mg, Pb, Tl, U and Zn) in human hair. In addition, the hair samples from MA showed statistically significant differences between males and females for a larger number of elements than those in NMA in which only Ag, Bi and Se were significantly different. This result implies a potential influence of mining activities on residents living in the vicinity. These findings confirm the need for competent authorities to act as early as possible and to implement strategies aimed to protect exposed populations and the entire ecosystem. PMID:26407230

  18. Sylvester theorem and the multichannel transfer matrix method for arbitrary transverse potential profile inside a wave guide

    SciTech Connect

    Anzaldo-Meneses, A.; Pereyra, P. . E-mail: ppereyra@correo.azc.uam.mx

    2007-09-15

    Based on the Sylvester and Frobenius theorems, we drastically enhance the feasibility of the transfer-matrix approach to deal with problems involving a large number of propagating and interfering modes, which require the solution of coupled differential equations and the evaluation of functions of matrix variables. We report closed formulas for the spectral decomposition of this type of functions. As specific example, besides the calculation of simple and well-known 1D one channel transfer matrices, we derive the multi-channel transfer matrix for an electron gas in the presence of a transverse electric field.

  19. First performance tests of a digital photon counter (DPC) array coupled to a CsI(Tl) crystal matrix for potential use in SPECT.

    PubMed

    Georgiou, Maria; Borghi, Giacomo; Spirou, Spiridon V; Loudos, George; Schaart, Dennis R

    2014-05-21

    The digital photon counter (DPC) is a recently developed type of digital silicon photomultiplier that combines low dark count rates, low readout noise, and fully digital, integrated readout circuitry with neighbor logic capability, system scalability, and MR compatibility. These are desirable properties for application in scintillation detectors for single photon emission computed tomography (SPECT). In this work, the feasibility of using a DPC array in combination with a CsI(Tl) crystal matrix as a potential detector for SPECT is investigated for the first time. Given the relatively long decay time of CsI(Tl), an important consideration is the influence on the detector performance of the DPC dark count rate as a function of temperature. We present a preliminary characterization of a detector assembled with an array of 2 × 2 × 3 mm(3) CsI(Tl) crystals. Preparatory measurements were acquired with a (57)Co source in order to optimize the light-guide thickness and the sensor settings. The spatial resolution of the detector was tested by acquiring flood maps with (57)Co as well as (99m)Tc sources. Three crystal identification algorithms were compared for the reconstruction of the flood maps. All crystal elements could be visualized clearly and high values of peak-to-valley ratios were achieved. Energy resolutions of ∼18.5% FWHM and ∼15% FWHM were measured at 122 keV and 140 keV, respectively. Temperature-dependent measurements indicate that the detector can work satisfactorily up to about 15 °C. PMID:24743522

  20. Influence of decellularized matrix derived from human mesenchymal stem cells on their proliferation, migration and multi-lineage differentiation potential.

    PubMed

    Lin, Hang; Yang, Guang; Tan, Jian; Tuan, Rocky S

    2012-06-01

    Developing biomaterials to promote stem cell proliferation and differentiation is a critical requirement in tissue engineering and regeneration. Extracellular matrix (ECM) derived from mesenchymal stem cells (MSCs) has recently been shown to be able to maintain the differentiation potential of MSCs during culture expansion and to restore the activities of aging MSCs, suggesting that MSC ECM (MECM) may be a suitable culture substrate to enhance the bioactivity of biomaterial scaffolds for MSCs. This investigation aims to characterize the biological nature and specificity of the influence of the MECM on MSCs. Native ECM produced by human MSC in vitro was extracted in urea, and the residual pellet was further processed with pepsin digestion (denoted as U-MECM and HP-MECM, respectively). The MECM products were then coated as a substrate on standard tissue culture plastic, and the behavior of MSCs seeded on the coated surfaces was studied. Our results showed that U-MECM coating dramatically accelerated MSC proliferation, attachment, spread, migration and multi-lineage differentiation (i.e., osteogenesis and adipogenesis), compared to collagen type I and HP-MECM coating. Non-collagenous proteins are likely the bioactive components in U-MECM, as MSCs cultured on collagen type I and HP-MECM showed similar biological activities, and collagen type I appeared to be the major protein components remaining in HP-MECM based on SDS-PAGE. These findings support the biological utility of MECM in the formulation of biomaterial scaffolds to enhance MSC bioactivities, including proliferation, migration and multi-lineage differentiation, for tissue regeneration applications.

  1. Influence of hydro-climatic conditions, soil type, and application matrix on potential vadose zone export of PPCPs

    NASA Astrophysics Data System (ADS)

    Gall, H. E.; Rao, P.; O'Connor, G.

    2013-12-01

    The land-application of biosolids and animal manure to agricultural fields has the potential to negatively impact the quality of nearby surface and subsurface water due to the presence of emerging contaminants in these residuals. We investigated the extent to which the vadose zone acts as a hydrologic and biogeochemical filter of two emerging contaminants, Triclosan (TCS) and estrone (E1) using a coupled source zone and vadose zone modeling approach. Monte Carlo simulations were run for a year following residual applications to explore the following research questions: (1) how does the application matrix (e.g., de-watered solids, liquid lagoon effluent, etc.) affect PPCP mass fluxes?; (2) how do hydro-climatic conditions and soil type affect PPCP mass fluxes?; (3) what role does the presence of macropore pathways play in PPCP export from the vadose zone; and (4) does the long-term, repeated application of residuals affect the ability of the vadose zone to act as an effective biogeochemical filter? The simulations were conducted for a sub-tropical climate with sand (e.g., Florida) and a humid climate with a silty clay loam (e.g., Midwestern United States). Simulation results suggest that the potential mobility of emerging contaminants increases linearly with increasing fraction applied to the mobile phase of the source zone (i.e., higher PPCP mass fraction in the dissolved phase during application). Following a single application, the total amount of PPCP mass exported from the source zone over the course of a year can be as high as 70% in a sub-tropical climate with sand soil. However, these types of soils do not have macropore flow pathways and the annual PPCP mass exported from the vadose zone is less than 1% of the mass applied. The higher organic carbon content in a silty clay loam reduces the amount of PPCP mass released from the source zone to less than 5% of the mass applied. In the presence of macropore pathways, the silty clay loam's vadose zone acts as a

  2. Calculation of electronic coupling matrix elements for ground and excited state electron transfer reactions: Comparison of the generalized Mulliken-Hush and block diagonalization methods

    NASA Astrophysics Data System (ADS)

    Cave, Robert J.; Newton, Marshall D.

    1997-06-01

    Two independent methods are presented for the nonperturbative calculation of the electronic coupling matrix element (Hab) for electron transfer reactions using ab initio electronic structure theory. The first is based on the generalized Mulliken-Hush (GMH) model, a multistate generalization of the Mulliken Hush formalism for the electronic coupling. The second is based on the block diagonalization (BD) approach of Cederbaum, Domcke, and co-workers. Detailed quantitative comparisons of the two methods are carried out based on results for (a) several states of the system Zn2OH2+ and (b) the low-lying states of the benzene-Cl atom complex and its contact ion pair. Generally good agreement between the two methods is obtained over a range of geometries. Either method can be applied at an arbitrary nuclear geometry and, as a result, may be used to test the validity of the Condon approximation. Examples of nonmonotonic behavior of the electronic coupling as a function of nuclear coordinates are observed for Zn2OH2+. Both methods also yield a natural definition of the effective distance (rDA) between donor (D) and acceptor (A) sites, in contrast to earlier approaches which required independent estimates of rDA, generally based on molecular structure data.

  3. Distal Interleukin-1β (IL-1β) Response Element of Human Matrix Metalloproteinase-13 (MMP-13) Binds Activator Protein 1 (AP-1) Transcription Factors and Regulates Gene Expression*

    PubMed Central

    Schmucker, Adam C.; Wright, Jason B.; Cole, Michael D.; Brinckerhoff, Constance E.

    2012-01-01

    The collagenase matrix metalloproteinase-13 (MMP-13) plays an important role in the destruction of cartilage in arthritic joints. MMP-13 expression is strongly up-regulated in arthritis, largely because of stimulation by inflammatory cytokines such as IL-1β. Treatment of chondrocytes with IL-1β induces transcription of MMP-13 in vitro. IL-1β signaling converges upon the activator protein-1 transcription factors, which have been shown to be required for IL-1β-induced MMP-13 gene expression. Using chromatin immunoprecipitation (ChIP), we detected activator protein-1 binding within an evolutionarily conserved DNA sequence ∼20 kb 5′ relative to the MMP-13 transcription start site (TSS). Also using ChIP, we detected histone modifications and binding of RNA polymerase II within this conserved region, all of which are consistent with transcriptional activation. Chromosome conformation capture indicates that chromosome looping brings this region in close proximity with the MMP-13 TSS. Finally, a luciferase reporter construct driven by a component of the conserved region demonstrated an expression pattern similar to that of endogenous MMP-13. These data suggest that a conserved region at 20 kb upstream from the MMP-13 TSS includes a distal transcriptional response element of MMP-13, which contributes to MMP-13 gene expression. PMID:22102411

  4. Search for a standard model Higgs boson produced in association with a top-quark pair and decaying to bottom quarks using a matrix element method

    DOE PAGES

    Khachatryan, Vardan

    2015-06-09

    A search for a standard model Higgs boson produced in association with a top-quark pair and decaying to bottom quarks is presented. Events with hadronic jets and one or two oppositely charged leptons are selected from a data sample corresponding to an integrated luminosity of 19.5fb-1 collected by the CMS experiment at the LHC in pp collisions at a centre-of-mass energy of 8TeV. In order to separate the signal from the larger tt¯ + jets background, this analysis uses a matrix element method that assigns a probability density value to each reconstructed event under signal or background hypotheses. The ratiomore » between the two values is used in a maximum likelihood fit to extract the signal yield. The results are presented in terms of the measured signal strength modifier, μ, relative to the standard model prediction for a Higgs boson mass of 125GeV. The observed (expected) exclusion limit at a 95 % confidence level is μ < 4.2 (3.3), corresponding to a best fit value μ^ = 1.2+1.6-1.5.« less

  5. A Search for the Higgs Boson Produced in Association with $Z\\to \\ell^+\\ell^-$ Using the Matrix Element Method at CDF II

    SciTech Connect

    Aaltonen, T.; Adelman, J.; Akimoto, T.; Alvarez Gonzalez, B.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A.; Antos, J.; Apollinari, G.; Apresyan, A.; /Purdue U. /Waseda U.

    2009-08-01

    We present a search for associated production of the standard model (SM) Higgs boson and a Z boson where the Z boson decays to two leptons and the Higgs decays to a pair of b quarks in p{bar p} collisions at the Fermilab Tevatron. We use event probabilities based on SM matrix elements to construct a likelihood function of the Higgs content of the data sample. In a CDF data sample corresponding to an integrated luminosity of 2.7 fb{sup -1} we see no evidence of a Higgs boson with a mass between 100 GeV/c{sup 2} and 150 GeV/c{sup 2}. We set 95% confidence level (C.L.) upper limits on the cross-section for ZH production as a function of the Higgs boson mass m{sub H}; the limit is 8.2 times the SM prediction at m{sub H} = 115 GeV/c{sup 2}.

  6. Spectral diagnostics based on Doppler-broadened H{sub α} line shape in a single element of a matrix source

    SciTech Connect

    Iordanova, S.; Pashov, A.

    2015-04-08

    The study is on optical emission spectroscopy diagnostics of a single element of a matrix source of negative hydrogen ions. The method developed for description of the hydrogen atoms behaviour is based on analysis of the Balmer H{sub α} line profile, and it can be readily applied to various low pressure hydrogen discharges. The present observations reveal the existence of thermal as well as of non-thermal fast hydrogen atoms in the discharge. For processing of the experimental data a line shape model, which accounts for details of the plasma kinetics and the fine structure of the Balmer lines is developed. The fit of this model to the recorded at different experimental conditions line shapes results in the temperature of the thermal atoms, the mean energy of the fast atoms, the ratio between the densities of these two group of atoms and the relative populations of the fine structure components of the n = 3 hydrogen state. The present study indicates that the reactions leading to production of fast atoms and the process of energy exchange between thermal and fast atoms may be important for the correct modeling of the plasma kinetics.

  7. Search for a standard model Higgs boson produced in association with a top-quark pair and decaying to bottom quarks using a matrix element method

    SciTech Connect

    Khachatryan, Vardan

    2015-06-09

    A search for a standard model Higgs boson produced in association with a top-quark pair and decaying to bottom quarks is presented. Events with hadronic jets and one or two oppositely charged leptons are selected from a data sample corresponding to an integrated luminosity of 19.5fb-1 collected by the CMS experiment at the LHC in pp collisions at a centre-of-mass energy of 8TeV. In order to separate the signal from the larger tt¯ + jets background, this analysis uses a matrix element method that assigns a probability density value to each reconstructed event under signal or background hypotheses. The ratio between the two values is used in a maximum likelihood fit to extract the signal yield. The results are presented in terms of the measured signal strength modifier, μ, relative to the standard model prediction for a Higgs boson mass of 125GeV. The observed (expected) exclusion limit at a 95 % confidence level is μ < 4.2 (3.3), corresponding to a best fit value μ^ = 1.2+1.6-1.5.

  8. Novel approaches for correction against the soft matrix effects in the quantitative elemental imaging of human substantia nigra tissue using synchrotron X-ray fluorescence

    NASA Astrophysics Data System (ADS)

    Surowka, A. D.; Wrobel, P.; Marzec, M. M.; Adamek, D.; Szczerbowska-Boruchowska, M.

    2016-09-01

    The inherent structural heterogeneity of biological specimens poses a number of problems for analytical techniques to assess for the elemental composition of a sample, and this is the case with quantitative X-ray fluorescence (XRF). Differences in density along with any possible variation in thickness upon frequently used freeze drying of thin samples could influence the results of the quantification and therefore underlie one of the most critical matrix effects in XRF, often referred to as the mass thickness effect. In our study, we analyzed substantia nigra tissue samples of various thicknesses mounted onto silicon nitride membranes. The aim was to show up the variation in the mass thickness of the different substantia nigra tissue compartments: the neuromelanine pigmented neurons and neuropil could influence the final quantitative results. In that respect, the main goal was to derive several semi- and fully-quantitative methods to correct for the mass thickness effects using either a membrane Si transmission signal or the intensity of incoherently scattered primary X-ray radiation. Also, the pioneer topographic studies on dried substantia nigra tissue specimens demonstrated the drying procedure is accompanied by an around 80% reduction in the samples' thickness. The correction scheme is presented together with the semi-theoretical procedure developed to compute for the mass thickness for substantia nigra tissue structures, and the correction scheme's robustness is also presented.

  9. Potential of Cultivated Ganoderma lucidum Mushrooms for the Production of Supplements Enriched with Essential Elements.

    PubMed

    Rzymski, Piotr; Mleczek, Mirosław; Niedzielski, Przemysław; Siwulski, Marek; Gąsecka, Monika

    2016-03-01

    Ganoderma lucidum is an important medicinal mushroom species and there is continuous interest in its bioactive properties. This study evaluated whether it may additionally serve as a nutritional supplement for the trace elements: selenium (Se), copper (Cu), and zinc (Zn). Mushrooms were cultivated on substrates enriched with 0.1 to 0.8 mM of inorganic Se alone or in combination with Zn and/or Cu. Supplementation increased accumulation of the elements in fruiting bodies regardless of the applied cultivation model. G. lucidum demonstrated the ability to accumulate significant amounts of organic Se, maximally amounting to (i) over 44 mg/kg when the substrate was supplemented only with Se, (ii) over 20 mg/kg in the Se+Cu model, (iii) over 25 mg/kg in the Se+Zn model, and (iv) 15 mg/kg in the Se+Cu+Zn model. The accumulation of Cu and Zn steadily increased with their initial substrate concentrations. Maximum concentrations found after supplementation with 0.8 mM amounted to over 55 mg/kg (Se+Zn) and 52 mg/kg (Se+Cu+Zn) of Zn, and 29 mg/kg (Se+Cu) and over 31 mg/kg (Se+Cu+Zn) of Cu. The greater the supplemented concentration and number of supplemented elements, the lower the biomass of G. lucidum fruiting bodies. Nevertheless, it still remained high when the substrate was supplemented up to 0.4 mM with each element. These results highlight that G. lucidum can easily incorporate elements from the substrate and that, when biofortified, its dried fruiting bodies may serve as a nutritional source of these essential elements. PMID:26799621

  10. Potential of Cultivated Ganoderma lucidum Mushrooms for the Production of Supplements Enriched with Essential Elements.

    PubMed

    Rzymski, Piotr; Mleczek, Mirosław; Niedzielski, Przemysław; Siwulski, Marek; Gąsecka, Monika

    2016-03-01

    Ganoderma lucidum is an important medicinal mushroom species and there is continuous interest in its bioactive properties. This study evaluated whether it may additionally serve as a nutritional supplement for the trace elements: selenium (Se), copper (Cu), and zinc (Zn). Mushrooms were cultivated on substrates enriched with 0.1 to 0.8 mM of inorganic Se alone or in combination with Zn and/or Cu. Supplementation increased accumulation of the elements in fruiting bodies regardless of the applied cultivation model. G. lucidum demonstrated the ability to accumulate significant amounts of organic Se, maximally amounting to (i) over 44 mg/kg when the substrate was supplemented only with Se, (ii) over 20 mg/kg in the Se+Cu model, (iii) over 25 mg/kg in the Se+Zn model, and (iv) 15 mg/kg in the Se+Cu+Zn model. The accumulation of Cu and Zn steadily increased with their initial substrate concentrations. Maximum concentrations found after supplementation with 0.8 mM amounted to over 55 mg/kg (Se+Zn) and 52 mg/kg (Se+Cu+Zn) of Zn, and 29 mg/kg (Se+Cu) and over 31 mg/kg (Se+Cu+Zn) of Cu. The greater the supplemented concentration and number of supplemented elements, the lower the biomass of G. lucidum fruiting bodies. Nevertheless, it still remained high when the substrate was supplemented up to 0.4 mM with each element. These results highlight that G. lucidum can easily incorporate elements from the substrate and that, when biofortified, its dried fruiting bodies may serve as a nutritional source of these essential elements.

  11. Ionization potentials, electron affinities, resonance excitation energies, oscillator strengths, and ionic radii of element Uus (Z = 117) and astatine.

    PubMed

    Chang, Zhiwei; Li, Jiguang; Dong, Chenzhong

    2010-12-30

    Multiconfiguration Dirac-Fock (MCDF) method was employed to calculate the first five ionization potentials, electron affinities, resonance excitation energies, oscillator strengths, and radii for the element Uus and its homologue At. Main valence correlation effects were taken into account. The Breit interaction and QED effects were also estimated. The uncertainties of calculated IPs, EAs, and IR for Uus and At were reduced through an extrapolation procedure. The good consistency with available experimental and other theoretical values demonstrates the validity of the present results. These theoretical data therefore can be used to predict some unknown physicochemical properties of element Uus, Astatine, and their compounds. PMID:21141866

  12. Ionization potentials, electron affinities, resonance excitation energies, oscillator strengths, and ionic radii of element Uus (Z = 117) and astatine.

    PubMed

    Chang, Zhiwei; Li, Jiguang; Dong, Chenzhong

    2010-12-30

    Multiconfiguration Dirac-Fock (MCDF) method was employed to calculate the first five ionization potentials, electron affinities, resonance excitation energies, oscillator strengths, and radii for the element Uus and its homologue At. Main valence correlation effects were taken into account. The Breit interaction and QED effects were also estimated. The uncertainties of calculated IPs, EAs, and IR for Uus and At were reduced through an extrapolation procedure. The good consistency with available experimental and other theoretical values demonstrates the validity of the present results. These theoretical data therefore can be used to predict some unknown physicochemical properties of element Uus, Astatine, and their compounds.

  13. [Comparison of event-related potentials components characteristics obtained during stimulation of symbolical and alphabetic matrixes used in brain-computer interface paradigm].

    PubMed

    Saltykov, K A; Bark, E D; Kulikov, M A

    2014-01-01

    In order to create a brain-computer interface (BCI) on the basis of paradigm P300 (the so-called Farwell-Donchin paradigm, FD) with a symbolical matrix used as stimuli, there were compared characteristics of event-related potentials (ERP) obtained from stimulation both by symbolical and alphabetical matrixes. The matrixes contained 6 x 6 signs (cyrillic letters or symbols-pictograms). Nine healthy adults were examined in 18 experiments during which 28 channel EEG were recorded while matrixes of two types (containing either cyrillic letters or symbols-pictograms) were used for stimulation. The obtained ERP data, i.e. amplitudes and peak latencies of the following components of ERP: N1, P3 with sub-components P3a and P3b, N4 were compared and analized for different types of the stimulation matrixes. Similar changes in amplitude or peak latency received from 7 or more out of 9 examinees were taken into consideration, matching the criteria of significance. It was discovered that for components P3a, P3b and N4 the amplitudes of ERP in response to a symbolic matrix were bigger than to a letter matrix, the opposite being true for component N1. Latent periods of ERP components were shorter for a symbolic matrix than for a letter matrix in case of components N1 and P3a, and longer in case of P3b and N4. In order to find out which zones of the brain react to stimulation the most, there was conducted a pair t-test (series of pair t-tests) to analize the topography of variety of ERP responses to different types of stimuli, and, through comparing the amplitudes of ERP components, a topographical map detailing the variety of responses to the different types of matrixes was obtained. The data about the differences were analized separately for each of 28 channels, then the (absolute magnitude t-test) were summed up algebraically for all the nine examinees. Thus, it was shown, for amplitudes of all the tested ERP components in the case of pair "significant-insignificant letters

  14. Potential Novel Mechanism for Axenfeld-Rieger Syndrome: Deletion of a Distant Region Containing Regulatory Elements of PITX2

    PubMed Central

    Volkmann, Bethany A.; Zinkevich, Natalya S.; Mustonen, Aki; Schilter, Kala F.; Bosenko, Dmitry V.; Reis, Linda M.; Broeckel, Ulrich; Link, Brian A.

    2011-01-01

    Purpose. Mutations in PITX2 are associated with Axenfeld-Rieger syndrome (ARS), which involves ocular, dental, and umbilical abnormalities. Identification of cis-regulatory elements of PITX2 is important to better understand the mechanisms of disease. Methods. Conserved noncoding elements surrounding PITX2/pitx2 were identified and examined through transgenic analysis in zebrafish; expression pattern was studied by in situ hybridization. Patient samples were screened for deletion/duplication of the PITX2 upstream region using arrays and probes. Results. Zebrafish pitx2 demonstrates conserved expression during ocular and craniofacial development. Thirteen conserved noncoding sequences positioned within a gene desert as far as 1.1 Mb upstream of the human PITX2 gene were identified; 11 have enhancer activities consistent with pitx2 expression. Ten elements mediated expression in the developing brain, four regions were active during eye formation, and two sequences were associated with craniofacial expression. One region, CE4, located approximately 111 kb upstream of PITX2, directed a complex pattern including expression in the developing eye and craniofacial region, the classic sites affected in ARS. Screening of ARS patients identified an approximately 7600-kb deletion that began 106 to 108 kb upstream of the PITX2 gene, leaving PITX2 intact while removing regulatory elements CE4 to CE13. Conclusions. These data suggest the presence of a complex distant regulatory matrix within the gene desert located upstream of PITX2 with an essential role in its activity and provides a possible mechanism for the previous reports of ARS in patients with balanced translocations involving the 4q25 region upstream of PITX2 and the current patient with an upstream deletion. PMID:20881290

  15. Objective Assessment of an Ionic Footbath (IonCleanse): Testing Its Ability to Remove Potentially Toxic Elements from the Body

    PubMed Central

    Kennedy, Deborah A.; Cooley, Kieran; Einarson, Thomas R.; Seely, Dugald

    2012-01-01

    Ionic footbaths are often used in holistic health centres and spas to aid in detoxification; however, claims that these machines eliminate toxins from the body have not been rigorously evaluated. In this proof-of-principle study, we sought to measure the release of potentially toxic elements from ionic footbaths into distilled and tap water with and without feet. Water samples were collected and analyzed following 30-minute ionic footbath sessions without feet using both distilled (n = 1) and tap water (n = 6) and following four ionic footbaths using tap water (once/week for 4 weeks) in six healthy participants. Urine collection samples were analyzed at four points during the study. Hair samples were analyzed for element concentrations at baseline and study conclusion. Contrary to claims made for the machine, there does not appear to be any specific induction of toxic element release through the feet when running the machine according to specifications. PMID:22174728

  16. Objective assessment of an ionic footbath (IonCleanse): testing its ability to remove potentially toxic elements from the body.

    PubMed

    Kennedy, Deborah A; Cooley, Kieran; Einarson, Thomas R; Seely, Dugald

    2012-01-01

    Ionic footbaths are often used in holistic health centres and spas to aid in detoxification; however, claims that these machines eliminate toxins from the body have not been rigorously evaluated. In this proof-of-principle study, we sought to measure the release of potentially toxic elements from ionic footbaths into distilled and tap water with and without feet. Water samples were collected and analyzed following 30-minute ionic footbath sessions without feet using both distilled (n = 1) and tap water (n = 6) and following four ionic footbaths using tap water (once/week for 4 weeks) in six healthy participants. Urine collection samples were analyzed at four points during the study. Hair samples were analyzed for element concentrations at baseline and study conclusion. Contrary to claims made for the machine, there does not appear to be any specific induction of toxic element release through the feet when running the machine according to specifications. PMID:22174728

  17. Long-term use of biosolids as organic fertilizers in agricultural soils: potentially toxic elements occurrence and mobility.

    PubMed

    Marguí, E; Iglesias, M; Camps, F; Sala, L; Hidalgo, M

    2016-03-01

    The presence of potentially toxic elements (PTEs) may hinder a more widespread application of biosolids in agriculture. At present, the European Directive 86/278/CEE limit the total concentrations of seven metals (Cu, Cr, Ni, Pb, Zn, Cd and Hg) in agricultural soils and in sewage sludges used as fertilizers but it has not taken into consideration the potential impacts of other emerging micropollutants that may be present in the biosolids as well as their mobility. The aim of this study was to evaluate the accumulation and mobility of 13 elements (including regulated metals and other inorganic species) in agricultural soils repeatedly amended with biosolids for 15 years. Firstly, three digestions programs using different acid mixtures were tested to evaluate the most accurate and efficient method for analysis of soil and sludge. Results demonstrated that sewage sludge application increased concentrations of Pb and Hg in soil, but values did not exceed the quality standard established by legislation. In addition, other elements (As, Co, Sb, Ag, Se and Mn) that at present are not regulated by the Spanish and European directives were identified in the sewage sludge, and significant differences were found between Ag content in soils amended with biosolids in comparison with control soils. This fact can be related to the increasing use of silver nanoparticles in consumer products due to their antibacterial properties. Results from the leaching tests show up that, in general, the mobility degree for both regulated and non-regulated elements in soils amended with biosolids was quite low (<10 %).

  18. The Kuril Islands as a potential region for aquaculture: Trace elements in chum salmon.

    PubMed

    Khristoforova, Nadezhda K; Tsygankov, Vasiliy Yu; Lukyanova, Olga N; Boyarova, Margarita D

    2016-06-01

    The Kuril Islands region is considered promising for development of salmon aquaculture. There are 41 salmon fish hatcheries in the Sakhalin Island and the Kuril Islands, 34 of them are hatcheries of the chum. Therefore, concentrations of six elements (Zn, Cu, Cd, Pb, As, and Hg) were determined in chum salmon were caught in this region. The contents of toxic elements (Cd, Pb, As, and Hg) don't exceed their maximum permissible concentrations (MPC) according to the Russian sanitary standards, but concentration of Pb are closely to MPC. Increased concentrations of Pb in wild chum have the natural origin. The unusual conditions of the Western Pacific are formed under the influence such factors as volcanism and upwelling.

  19. The feasibility of RIMS for the analysis of potentially toxic element accumulation in neural tissue

    SciTech Connect

    Jones, O. Rhodri; Abraham, Christopher J.; Telle, Helmut H.; Oakley, Arthur E.

    1997-01-15

    A feasibility study was conducted into the possibility of using resonance ionisation mass spectrometry for the detection of focal accumulation of neuro-toxic elements in neural tissue. Experiments were performed using a ToFMS system in conjunction with an Ar{sup +} source for target sputtering and a pulsed tuneable dye laser system for resonance ionisation. Detection limits of {approx}3 ppm for Al in brain tissue homogenates were achieved, with a spatial resolution of less than 100 {mu}m.

  20. Data analysis techniques, differential cross sections, and spin density matrix elements for the reaction γp → Φp

    DOE PAGES

    Dey, B.; Meyer, C. A.; Bellis, M.; Williams, M.; Adhikari, K. P.; Adikaram, D.; Aghasyan, M.; Amaryan, M. J.; Anderson, M. D.; Anefalos Pereira, S.; et al

    2014-05-27

    High-statistics measurements of differential cross sections and spin density matrix elements for the reaction γ p → Φp have been made using the CLAS detector at Jefferson Lab. We cover center-of-mass energies (√s) from 1.97 to 2.84 GeV, with an extensive coverage in the Φ production angle. The high statistics of the data sample made it necessary to carefully account for the interplay between the Φ natural lineshape and effects of the detector resolution, that are found to be comparable in magnitude. We study both the charged- (Φ → K⁺K⁻) and neutral- (Φ → K0SK0L)more » $$K\\bar{K}$$ decay modes of the Φ. Further, for the charged mode, we differentiate between the cases where the final K⁻ track is directly detected or its momentum reconstructed as the total missing momentum in the event. The two charged-mode topologies and the neutral-mode have different resolutions and are calibrated against each other. Extensive usage is made of kinematic fitting to improve the reconstructed Φ mass resolution. Our final results are reported in 10- and mostly 30-MeV-wide √s bins for the charged- and the neutral-mode, respectively. Possible effects from K⁺Λ* channels with p$$K\\bar{K}$$ final-states are discussed. These present results constitute the most precise and extensive Φ photoproduction measurements to date and in conjunction with the ω photoproduction results recently published by CLAS, will greatly improve our understanding of low energy vector meson photoproduction.« less

  1. Determination of the Form Factors for the Decay B0 -> D*-l+nu_l and of the CKM Matrix Element |Vcb|

    SciTech Connect

    Aubert, B.

    2006-09-26

    The authors present a combined measurement of the Cabibbo-Kobayashi-Maskawa matrix element |V{sub cb}| and of the parameters {rho}{sup 2}, R{sub 1}, and R{sub 2}, which fully characterize the form factors of the B{sup 0} {yields} D*{sup -}{ell}{sup +}{nu}{sub {ell}} decay in the framework of HQET, based on a sample of about 52,800 B{sup 0} {yields} D*{sup -}{ell}{sup +}{nu}{sub {ell}} decays recorded by the BABAR detector. The kinematical information of the fully reconstructed decay is used to extract the following values for the parameters (where the first errors are statistical and the second systematic): {rho}{sup 2} = 1.156 {+-} 0.094 {+-} 0.028, R{sub 1} = 1.329 {+-} 0.131 {+-} 0.044, R{sub 2} = 0.859 {+-} 0.077 {+-} 0.022, F(1)|V{sub cb}| = (35.03 {+-} 0.39 {+-} 1.15) x 10{sup -3}. By combining these measurements with the previous BABAR measurements of the form factors which employs a different technique on a partial sample of the data, they improve the statistical accuracy of the measurement, obtaining: {rho}{sup 2} = 1.179 {+-} 0.048 {+-} 0.028, R{sub 1} = 1.417 {+-} 0.061 {+-} 0.044, R{sub 2}, = 0.836 {+-} 0.037 {+-} 0.022, and F(1)|V{sub cb}| = (34.68 {+-} 0.32 {+-} 1.15) x 10{sup -3}. Using the lattice calculations for the axial form factor F(1), they extract |V{sub cb}| = (37.74 {+-} 0.35 {+-} 1.25 {+-} {sub 1.44}{sup 1.23}) x 10{sup -3}, where the third error is due to the uncertainty in F(1).

  2. Precision measurement of the top quark mass in the lepton + jets channel using a matrix element method with Quasi-Monte Carlo integration

    SciTech Connect

    Lujan, Paul Joseph

    2009-12-01

    This thesis presents a measurement of the top quark mass obtained from p$\\bar{p}$ collisions at √s = 1.96 TeV at the Fermilab Tevatron using the CDF II detector. The measurement uses a matrix element integration method to calculate a t$\\bar{t}$ likelihood, employing a Quasi-Monte Carlo integration, which enables us to take into account effects due to finite detector angular resolution and quark mass effects. We calculate a t$\\bar{t}$ likelihood as a 2-D function of the top pole mass mt and ΔJES, where ΔJES parameterizes the uncertainty in our knowledge of the jet energy scale; it is a shift applied to all jet energies in units of the jet-dependent systematic error. By introducing ΔJES into the likelihood, we can use the information contained in W boson decays to constrain ΔJES and reduce error due to this uncertainty. We use a neural network discriminant to identify events likely to be background, and apply a cut on the peak value of individual event likelihoods to reduce the effect of badly reconstructed events. This measurement uses a total of 4.3 fb-1 of integrated luminosity, requiring events with a lepton, large ET, and exactly four high-energy jets in the pseudorapidity range |η| < 2.0, of which at least one must be tagged as coming from a b quark. In total, we observe 738 events before and 630 events after applying the likelihood cut, and measure mt = 172.6 ± 0.9 (stat.) ± 0.7 (JES) ± 1.1 (syst.) GeV/c2, or mt = 172.6 ± 1.6 (tot.) GeV/c2.

  3. ({sup 3}He,t) reaction on the double {beta} decay nucleus {sup 48}Ca and the importance of nuclear matrix elements

    SciTech Connect

    Grewe, E.-W.; Frekers, D.; Rakers, S.; Baeumer, C.; Dohmann, H.; Thies, J.; Adachi, T.; Fujita, Y.; Shimbara, Y.; Botha, N. T.; Fujita, H.; Hatanaka, K.; Nakanishi, K.; Sakemi, Y.; Shimizu, Y.; Tameshige, Y.; Tamii, A.; Negret, A.; Popescu, L.; Neveling, R.

    2007-11-15

    High-resolution ({sup 3}He,t) measurements on the double {beta}-decay ({beta}{beta}) nucleus {sup 48}Ca have been performed at RCNP (Osaka, Japan) to determine Gamow-Teller (GT{sup -}) transitions to the nucleus {sup 48}Sc, which represents the intermediate nucleus in the second-order perturbative description of the {beta}{beta} decay. At a bombarding energy of E{sub {sup 3}He}=420 MeV an excitation energy resolution of 40 keV was achieved. The measurements were performed at two angle positions of the Grand Raiden Spectrometer (GRS): 0 deg. and 2.5 deg. The results of both settings were combined to achieve angular distributions, by which the character of single transitions could be determined. To characterize the different multipoles, theoretical angular distributions for states with J{sup {pi}}=1{sup +},2{sup +},2{sup -}, and 3{sup +} were calculated using the distorted-wave Born approximation (DWBA) Code DW81. The GT{sup -} strength was extracted up to E{sub x}=7 MeV and combined with corresponding GT{sup +} strength deduced from the {sup 48}Ti(d,{sup 2}He){sup 48}Sc data to calculate the low-energy part of the {beta}{beta}-decay matrix element for the {sup 48}Ca 2{nu}{beta}{beta} decay. We show that after applying trivial momentum corrections to the ({sup 3}He,t) spectrum, the two reaction probes (p,n) and ({sup 3}He,t) reveal a spectral response to an impressively high degree of similarity in the region of low momentum transfer.

  4. The generalization of the extended Stevens operators to higher ranks and spins, and a systematic review of the tables of the tensor operators and their matrix elements

    NASA Astrophysics Data System (ADS)

    Rudowicz, C.; Chung, C. Y.

    2004-08-01

    Spherical (S) and tesseral (T) tensor operators (TOs) have been extensively used in, for example, EMR and optical spectroscopy of transition ions. To enable a systematic review of the published tables of the operators and their matrix elements (MEs) we have generated the relevant tables by computer, using Mathematica programs. Our review reveals several misprints/errors in the major sources of TTOs—the conventional Stevens operators (CSOs—components q\\ge 0 ) and the extended ones (ESOs—all q) for rank k = 2,4, and 6—as well as of some STOs with k\\le 8 . The implications of using incorrect operators and/or MEs for the reliability of EMR-related programs and interpretation of experimental data are discussed. Studies of high-spin complexes like Mn12 (S = 10) and Fe19 (S = 33/2) require operator and ME listings up to k = 2S, which are not presently available. Using the algorithms developed recently by Ryabov, the generalized ESOs and their MEs for arbitrary rank k and spin S are generated by computer, using Mathematica. The extended tables enable simulation of the energy levels for arbitrary spin systems and symmetry cases. Tables are provided for the ESOs not available in the literature, with odd k = 3,5, and 7 for completeness; however, for the newly generalized ESOs with the most useful even rank k = 8,10, and 12 only, in view of the large listings sizes. General source codes for the generation of the ESO listings and their ME tables are available from the authors.

  5. Laboratory assessment of the antifouling potential of a soluble-matrix paint laced with the natural compound polygodial.

    PubMed

    Cahill, Patrick Louis; Heasman, Kevin; Jeffs, Andrew; Kuhajek, Jeanne

    2013-09-01

    Polygodial is a potent and selective inhibitor of ascidian metamorphosis that shows promise for controlling fouling by ascidians in bivalve aquaculture. The current study examined the potency of, and associated effects of seawater exposure on, a rosin-based soluble-matrix paint laced with 0.08-160 ng polygodial g(-1) wet paint matrix. Paint-coated surfaces were soaked in seawater for 0, 2, 4 or 12 weeks prior to screening for antifouling activity using a bioassay based on the nuisance ascidian Ciona savignyi Herdman. Mortality was greater (mean 50% lethal concentration: 5 ± 2 ng g(-1); mean 75% lethal concentration: 17 ± 4 ng g(-1)) and metamorphosis was inhibited (mean 50% anti-metamorphic concentration: 2 ± 0.4 ng g(-1); mean 75% anti-metamorphic concentration: 15 ± 10 ng g(-1)) in C. savignyi larvae exposed to polygodial-laced soluble-matrix paints, relative to control paints without polygodial. Soaking in seawater prior to testing reduced the efficacy of the formulation up to nearly 12-fold, but even after soaking for 12 weeks paints laced with polygodial at 160 ng g(-1) wet paint matrix prevented ⩾90% of the larvae of C. savignyi from completing metamorphosis. The outcome of this experiment provides a positive first step in evaluating the suitability of polygodial-laced soluble-matrix paints for use in aquaculture.

  6. Improved 206Pb/238U microprobe geochronology by the monitoring of a trace-element-related matrix effect; SHRIMP, ID-TIMS, ELA-ICP-MS and oxygen isotope documentation for a series of zircon standards

    USGS Publications Warehouse

    Black, L.P.; Kamo, S.L.; Allen, C.M.; Davis, D.W.; Aleinikoff, J.N.; Valley, J.W.; Mundil, R.; Campbell, I.H.; Korsch, R.J.; Williams, I.S.; Foudoulis, C.

    2004-01-01

    Precise isotope dilution-thermal ionisation mass spectrometry (ID-TIMS) documentation is given for two new Palaeozoic zircon standards (TEMORA 2 and R33). These data, in combination with results for previously documented standards (AS3, SL13, QGNG and TEMORA 1), provide the basis for a detailed investigation of inconsistencies in 206Pb/238U ages measured by microprobe. Although these ages are normally consistent between any two standards, their relative age offsets are often different from those established by ID-TIMS. This is true for both sensitive high-resolution ion-microprobe (SHRIMP) and excimer laser ablation-inductively coupled plasma-mass spectrometry (ELA-ICP-MS) dating, although the age offsets are in the opposite sense for the two techniques. Various factors have been investigated for possible correlations with age bias, in an attempt to resolve why the accuracy of the method is worse than the indicated precision. Crystallographic orientation, position on the grain-mount and oxygen isotopic composition are unrelated to the bias. There are, however, striking correlations between the 206Pb/238U age offsets and P, Sm and, most particularly, Nd abundances in the zircons. Although these are not believed to be the primary cause of this apparent matrix effect, they indicate that ionisation of 206Pb/238U is influenced, at least in part, by a combination of trace elements. Nd is sufficiently representative of the controlling trace elements that it provides a quantitative means of correcting for the microprobe age bias. This approach has the potential to reduce age biases associated with different techniques, different instrumentation and different standards within and between laboratories. Crown Copyright ?? 2004 Published by Elsevier B.V. All rights reserved.

  7. Impact of the Parameter Identification of Plastic Potentials on the Finite Element Simulation of Sheet Metal Forming

    SciTech Connect

    Rabahallah, M.; Bouvier, S.; Bacroix, B.; Teodosiu, C.; Balan, T.

    2007-04-07

    In this work, an implicit, backward Euler time integration scheme is developed for an anisotropic, elastic-plastic model based on strain-rate potentials. The constitutive algorithm includes a sub-stepping procedure to deal with the strong nonlinearity of the plastic potentials when applied to FCC materials. The algorithm is implemented in the static implicit version of the Abaqus finite element code. Several recent plastic potentials have been implemented in this framework. The most accurate potentials require the identification of about twenty material parameters. Both mechanical tests and micromechanical simulations have been used for their identification, for a number of BCC and FCC materials. The impact of the identification procedure on the prediction of ears in cup drawing is investigated.

  8. Impact of the Parameter Identification of Plastic Potentials on the Finite Element Simulation of Sheet Metal Forming

    NASA Astrophysics Data System (ADS)

    Rabahallah, M.; Bouvier, S.; Balan, T.; Bacroix, B.; Teodosiu, C.

    2007-04-01

    In this work, an implicit, backward Euler time integration scheme is developed for an anisotropic, elastic-plastic model based on strain-rate potentials. The constitutive algorithm includes a sub-stepping procedure to deal with the strong nonlinearity of the plastic potentials when applied to FCC materials. The algorithm is implemented in the static implicit version of the Abaqus finite element code. Several recent plastic potentials have been implemented in this framework. The most accurate potentials require the identification of about twenty material parameters. Both mechanical tests and micromechanical simulations have been used for their identification, for a number of BCC and FCC materials. The impact of the identification procedure on the prediction of ears in cup drawing is investigated.

  9. Element accumulation, distribution, and phytoremediation potential in selected metallophytes growing in a contaminated area.

    PubMed

    Nadgórska-Socha, Aleksandra; Kandziora-Ciupa, Marta; Ciepał, Ryszard

    2015-07-01

    The distribution of elements in three pseudometallophytes species Cardaminopsis arenosa, Plantago lanceolata, and Plantago major, naturally occurring at metalliferous and non-metalliferous sites in southern Poland, was investigated. The accumulation of Al, Cd, Cu, Fe, Mn, Pb, Zn, as well as Ca, P, Na, and K in shoots and roots was measured. The level of the accumulated trace elements (ATE) was visibly higher in C. arenosa and P. lanceolata from metalliferous sites than non-contaminated ones. However, the level of the accumulated nutrient elements (ANE) was visibly higher only in C. arenosa plants. Also, higher potassium share in ANE was found in the shoots of C. arenosa and Plantago species from metalliferous sites than non-contaminated ones. The highest content of Cd, Zn, Pb, Al, Fe, and Mn was found in C. arenosa, which better reflected metal concentrations in the metalliferous and non-metalliferous soil than other plants. In the studied Plantago species, in almost all cases in all sites TF (translocation coefficient) and MR (mobility ratio) were below 1, which indicates they use the excluder strategy. The best accumulation ability was found for C. arenosa. The higher translocation coefficients (TF > 1) for Zn and Cd in C. arenosa shoots make it suitable for phytoextraction from soil, while the lower translocation ratios (TF < 1) for Zn and Cd in Plantago species and also for Pb in C. arenosa make them suitable for phytostabilization. Almost in all cases the plants had enrichment coefficient >2, which suggested that they may act as indicators of the soil metal contamination.

  10. Element accumulation, distribution, and phytoremediation potential in selected metallophytes growing in a contaminated area.

    PubMed

    Nadgórska-Socha, Aleksandra; Kandziora-Ciupa, Marta; Ciepał, Ryszard

    2015-07-01

    The distribution of elements in three pseudometallophytes species Cardaminopsis arenosa, Plantago lanceolata, and Plantago major, naturally occurring at metalliferous and non-metalliferous sites in southern Poland, was investigated. The accumulation of Al, Cd, Cu, Fe, Mn, Pb, Zn, as well as Ca, P, Na, and K in shoots and roots was measured. The level of the accumulated trace elements (ATE) was visibly higher in C. arenosa and P. lanceolata from metalliferous sites than non-contaminated ones. However, the level of the accumulated nutrient elements (ANE) was visibly higher only in C. arenosa plants. Also, higher potassium share in ANE was found in the shoots of C. arenosa and Plantago species from metalliferous sites than non-contaminated ones. The highest content of Cd, Zn, Pb, Al, Fe, and Mn was found in C. arenosa, which better reflected metal concentrations in the metalliferous and non-metalliferous soil than other plants. In the studied Plantago species, in almost all cases in all sites TF (translocation coefficient) and MR (mobility ratio) were below 1, which indicates they use the excluder strategy. The best accumulation ability was found for C. arenosa. The higher translocation coefficients (TF > 1) for Zn and Cd in C. arenosa shoots make it suitable for phytoextraction from soil, while the lower translocation ratios (TF < 1) for Zn and Cd in Plantago species and also for Pb in C. arenosa make them suitable for phytostabilization. Almost in all cases the plants had enrichment coefficient >2, which suggested that they may act as indicators of the soil metal contamination. PMID:26088758

  11. Bioinformatic Identification of Novel Elements Potentially Involved in Messenger RNA Fate Control During Spermatogenesis1

    PubMed Central

    Idler, R. Keegan; Hennig, Grant W.; Yan, Wei

    2012-01-01

    ABSTRACT In eukaryotic cells, 3′ untranslated regions (3′ UTRs) of mRNA transcripts contain conserved sequence elements (motifs), which, once bound by RNA-binding proteins, can affect mRNA stability and translational efficacy. Despite abundant sequences contained within the 3′ UTRs, only a limited number of motifs are known to interact with RNA-binding proteins and have a role in mRNA fate control. Spermatogenesis represents an excellent in vivo model for studying posttranscriptional regulation of gene expression because numerous mRNAs are transcribed in late pachytene spermatocytes and/or round spermatids, but their translation will not occur until many hours or even days later, when they have developed into elongated spermatids, in which transcription has long been shut off because of the increasingly condensed chromatin. Translationally suppressed mRNAs are sequestered and confined to ribonuclear protein particles, and their loading onto the ribosomes marks their translation. By bioinformatic sequence analyses of the 3′ UTRs of translationally suppressed mRNAs during spermatogenesis, we identified numerous novel sequence elements overrepresented in the transcripts subject to posttranscriptional regulation than in the unregulated transcripts. These include AU(U/A)(U/A)UGAGU and (A/U)AUUA(U/C/G) for genes translationally upregulated in early spermiogenesis, and (G/A)GUACG(U/C/A)(A/U)(A/U) and UGUAGC for genes translationally upregulated in late spermiogenesis. The bioinformatic approach reported in this study can be adapted for rapid discovery of novel regulatory elements involved in mRNA fate control in a wide range of tissues or organs. PMID:23053435

  12. Discrete-element modelling and smoothed particle hydrodynamics: potential in the environmental sciences.

    PubMed

    Cleary, Paul W; Prakash, Mahesh

    2004-09-15

    Particle-based simulation methods, such as the discrete-element method and smoothed particle hydrodynamics, have specific advantages in modelling complex three-dimensional (3D) environmental fluid and particulate flows. The theory of both these methods and their relative advantages compared with traditional methods will be discussed. Examples of 3D flows on realistic topography illustrate the environmental application of these methods. These include the flooding of a river valley as a result of a dam collapse, coastal inundation by a tsunami, volcanic lava flow and landslides. Issues related to validation and quality data availability are also discussed. PMID:15306427

  13. Finite Element Simulation of Sheet Metal Forming Using Anisotropic Strain-Rate Potentials

    NASA Astrophysics Data System (ADS)

    Rabahallah, Meziane; Balan, Tudor; Bouvier, Salima; Bacroix, Brigitte; Teodosiu, Cristian

    2007-05-01

    In continuum mechanics, plastic anisotropy is described using anisotropic stress potentials or, alternatively, strain-rate potentials. In this work, a stress update algorithm is developed for this later case. The implicit, backward Euler method is adopted. A specific numerical treatment is required to deal with the plasticity criterion, which is not defined explicitly. Also, a sub-stepping procedure is adopted in order to deal with the strong nonlinearity of the yield surfaces when applied to FCC materials. The resulting algorithm is implemented in the static implicit version of the Abaqus FE code. Several recent plastic potentials have been implemented in this framework and their parameters identified for a number of BCC and FCC materials. Numerical simulations of a cup drawing process are performed in order to address the robustness of the implementation and the ability of these potentials to predict e.g. earing for materials with different anisotropy.

  14. Coal quality trends and distribution of potentially hazardous trace elements in Eastern Kentucky coals

    USGS Publications Warehouse

    Eble, C.F.; Hower, J.C.

    1997-01-01

    Coal in the Eastern Kentucky coalfield has been, and continues to be, a valuable energy resource, especially for the electric utility industry. However, Federal mandates in Titles III and IV of the Clean Air Act Amendments of 1990 have placed increasingly stringent demands on the type and grade of coal that can be burnt in an environmentally acceptable manner. Therefore, a greater understanding of the spatial and temporal distribution of thickness and quality parameters, and the geologic factors that control their distribution, is critical if the Eastern Kentucky coalfield is to continue to be a major producer of high-quality coal. Information from the Kentucky Geological Survey's Coal Resource Information System database is used in this paper to document the geographic and stratigraphic distribution of important factors such as bed thickness, calorific value, ash yield and total sulfur content. The distribution of 15 elements that naturally occur in trace amounts in Kentucky coal is also discussed, as these elements may require monitoring with passage of Title III of the Clean Air Act Amendments of 1990. ?? 1997 Elsevier Science Ltd.

  15. Accumulation of potentially toxic elements in plants and their transfer to human food chain.

    PubMed

    Dudka, S; Miller, W P

    1999-07-01

    Contaminated soils can be a source for crop plants of such elements like As, Cd, Cr, Cu, Ni, Pb, and Zn. The excessive transfer of As, Cu, Ni, and Zn to the food chain is controlled by a "soil-plant barrier"; however, for some elements, including Cd, the soil-plant barrier fails. The level of Cd ingested by average person in USA is about 12 micrograms/day, which is relatively low comparing to Risk Reference Dose (70 micrograms Cd/day) established by USEPA. Food of plant origin is a main source of Cd intake by modern society. Fish and shellfish may be a dominant dietary sources of Hg for some human populations. About half of human Pb intake is through food, of which more than half originates from plants. Dietary intake of Cd and Pb may be increased by application of sludges on cropland with already high levels of these metals. Soils amended with sludges in the USA will be permitted (by USEPA-503 regulations) to accumulate Cr, Cd, Cu, Pb, Hg, Ni, and Se, and Zn to levels from 10 to 100 times the present baseline concentrations. These levels are very permissive by international standards. Because of the limited supply of toxicity data obtained from metals applied in sewage sludge, predictions as to the new regulations will protect crop plants from metal toxicities, and food chain from contamination, are difficult to make.

  16. Matrix fractional systems

    NASA Astrophysics Data System (ADS)

    Tenreiro Machado, J. A.

    2015-08-01

    This paper addresses the matrix representation of dynamical systems in the perspective of fractional calculus. Fractional elements and fractional systems are interpreted under the light of the classical Cole-Cole, Davidson-Cole, and Havriliak-Negami heuristic models. Numerical simulations for an electrical circuit enlighten the results for matrix based models and high fractional orders. The conclusions clarify the distinction between fractional elements and fractional systems.

  17. A new approach to the solution of large, full matrix equations: A two-dimensional potential flow feasibility study

    NASA Technical Reports Server (NTRS)

    James, R. M.; Clark, R. W.

    1979-01-01

    An approach to the solution of matrix problems resulting from integral equations of mathematical physics is presented. Based on the inherent smoothness in such equations, the problem is reformulated using a set of orthogonal basis vectors, leading to an equivalent coefficient problem which can be of lower order without significantly impairing the accuracy of the solution. This approach was evaluated using a two-dimensional Neumann problem describing the inviscid, incompressible flow over an airfoil. Two different kinds of mode functions were investigated, namely eigenfunction series and Fourier series. The method using Fourier series was found preferable. It uses all of the coefficients from a Fast Fourier Transform algorithm in an approximate method which exploits the known structure of the transformed coefficient matrix and very promising results for the flow over a realistic airfoil are obtained. On the basis of the results presented here, an order of magnitude reduction in this computer time can be expected for such problems as compared with the time for a direct matrix solution.

  18. Concentrations of arsenic and other elements in groundwater of Bangladesh and West Bengal, India: potential cancer risk.

    PubMed

    Rahman, Mohammad Mahmudur; Dong, Zhaomin; Naidu, Ravi

    2015-11-01

    We investigated the concentrations of 23 elements in groundwater from arsenic (As) contaminated areas of Bangladesh and West Bengal, India to determine the potential human exposure to metals and metalloids. Elevated concentrations of As was found in all five study areas that exceeded the World Health Organization (WHO) guideline value of 10μg/L. The mean As concentrations in groundwater of Noakhali, Jalangi and Domkal, Dasdia Nonaghata, Deganga and Baruipur were 297μg/L, 262μg/L, 115μg/L, 161μg/L and 349μg/L, respectively. Elevated concentrations of Mn were also detected in all areas with mean concentrations were 139μg/L, 807μg/L, 341μg/L, 579μg/L and 584μg/L for Noakhali, Jalangi and Domkal, Dasdia Nonaghata, Deganga and Baruipur, respectively. Daily As intakes from drinking water for adults and the potential cancer risk for all areas was also estimated. Results suggest that mitigation activities such as water treatment should not only be focused on As but must also consider other elements including Mn, B and Ba. The groundwater used for public drinking purposes needs to be tested periodically for As and other elements to ensure the quality of drinking water is within the prescribed national guidelines.

  19. Forward problem solution as the operator of filtered and back projection matrix to reconstruct the various method of data collection and the object element model in electrical impedance tomography

    SciTech Connect

    Ain, Khusnul; Kurniadi, Deddy; Suprijanto; Santoso, Oerip; Wibowo, Arif

    2015-04-16

    Back projection reconstruction has been implemented to get the dynamical image in electrical impedance tomography. However the implementation is still limited in method of adjacent data collection and circular object element model. The study aims to develop the methods of back projection as reconstruction method that has the high speed, accuracy, and flexibility, which can be used for various methods of data collection and model of the object element. The proposed method uses the forward problem solution as the operator of filtered and back projection matrix. This is done through a simulation study on several methods of data collection and various models of the object element. The results indicate that the developed method is capable of producing images, fastly and accurately for reconstruction of the various methods of data collection and models of the object element.

  20. Accumulation of potentially toxic elements in road deposited sediments in residential and light industrial neighborhoods of Singapore.

    PubMed

    Yuen, J Q; Olin, P H; Lim, H S; Benner, S G; Sutherland, R A; Ziegler, A D

    2012-06-30

    Road deposited sediments (RDS) are a valuable environmental medium for characterizing contaminant levels in urban areas; and their associated potentially toxic elements (PTEs) can directly impact both human and aquatic health. In this study, RDS were collected from 15 co-located industrial and residential roads throughout Singapore to determine the effect of land use on contaminant levels. A second pilot study was designed to quantify the efficiency of road sweeping in removing different RDS grain size fractions from industrial and residential roads. The fine fraction (<63 μm) of all RDSs was analyzed for over 40 elements. Eleven elements that reflect geogenic and anthropogenic sources were examined in detail (Al, Co, Cr, Cu, Fe, Ni, Pb, Sb, Sc, Si, and Zn). Industrial RDS had statistically higher concentrations of Co, Cr, Fe, and Ni than residential RDS. Potentially toxic elements Cu, Pb, Sb, and Zn were enriched >10-fold at all locations compared to upper continental crust values. Concentrations of Cu, Pb and Zn exceeded aquatic sediment probable effect concentration levels, suggesting they could generate a toxic response in bottom-dwelling aquatic organisms. Traffic was equally heavy at both industrial and residential sites, but large trucks and machinery comprised a larger proportion of the traffic in the industrial areas. Traffic was not significantly correlated with the PTE (i.e., Cu, Pb, Sb and Zn) concentrations. Plausible anthropogenic contaminant sources include vehicles (e.g., brake and tire wear, vehicle emissions) and several industrial activities including metal works, oil processing, and waste incineration. Street sweeping was effective in removal of large organic debris and inorganic RDS, but it was ineffective in removing the geochemically important fraction, i.e., <125 μm.

  1. Risk assessment of total and bioavailable potentially toxic elements (PTEs) in urban soils of Baghdad-Iraq.

    PubMed

    Hamad, Samera H; Schauer, James J; Shafer, Martin M; Al-Rheem, Esam Abd; Skaar, Pamela S; Heo, Jongbae; Tejedor-Tejedor, Isabel

    2014-10-01

    The solubility of soil-associated potentially toxic elements (PTEs) in surrogate biological fluids provides valuable information about their potential health hazard. This work addresses the concentrations and bioaccessibility of nine PTEs (As, Co, Cr, Cu, Mn, Ni, Pb, V, and Zn) in thirty eight agricultural land and playground soils collected from a semi-arid urban area of Baghdad-Iraq. Two surrogate biological fluids (SBFs), macrophage vacuole (MS) and gastric (GS) solutions, were used to extract the metals to simulate the biological availability of the PTEs via inhalation and ingestion exposure routes. ICP/AES was used to quantify PTEs in both strong acid digests (for total concentration), and in the SBF extracts. Soil contamination factors showed that some sites exhibited elevated levels of As (36 ± 10 mg/kg), however, these levels of As are not likely to have significant human health impacts whether the particulate arsenic is ingested or/and inhaled. Soil-geochemical variables (including: pH, EC, CO3(=), soil organic carbon (SOC)) and major elements (e.g. Al, Ca, and Fe) were used to interpret the lability of PTEs in the soils. Hazardous index (HI) based non-cancer risk of inhalation and ingestion of PTEs was estimated to be 2-fold higher for that based on total element concentrations compared with that for bioavailable fractions for both children and adults. A similar conclusion was reached for the estimated cancer risk (which was lower than the threshold level of concern for children and adults). A sensitivity analysis showed that there is a 97% chance for children and 90% for adults to have hazardous indices of the total PTEs >1 (the acceptable value); the corresponding metrics for the bioavailable fraction of the elements were 39% for children, and 3% for adults; these results were sensitive to the concentrations of "airborne" soil particles.

  2. Long-term use of biosolids as organic fertilizers in agricultural soils: potentially toxic elements occurrence and mobility.

    PubMed

    Marguí, E; Iglesias, M; Camps, F; Sala, L; Hidalgo, M

    2016-03-01

    The presence of potentially toxic elements (PTEs) may hinder a more widespread application of biosolids in agriculture. At present, the European Directive 86/278/CEE limit the total concentrations of seven metals (Cu, Cr, Ni, Pb, Zn, Cd and Hg) in agricultural soils and in sewage sludges used as fertilizers but it has not taken into consideration the potential impacts of other emerging micropollutants that may be present in the biosolids as well as their mobility. The aim of this study was to evaluate the accumulation and mobility of 13 elements (including regulated metals and other inorganic species) in agricultural soils repeatedly amended with biosolids for 15 years. Firstly, three digestions programs using different acid mixtures were tested to evaluate the most accurate and efficient method for analysis of soil and sludge. Results demonstrated that sewage sludge application increased concentrations of Pb and Hg in soil, but values did not exceed the quality standard established by legislation. In addition, other elements (As, Co, Sb, Ag, Se and Mn) that at present are not regulated by the Spanish and European directives were identified in the sewage sludge, and significant differences were found between Ag content in soils amended with biosolids in comparison with control soils. This fact can be related to the increasing use of silver nanoparticles in consumer products due to their antibacterial properties. Results from the leaching tests show up that, in general, the mobility degree for both regulated and non-regulated elements in soils amended with biosolids was quite low (<10 %). PMID:26507732

  3. Rare earth elements and critical metal content of extracted landfilled material and potential recovery opportunities

    SciTech Connect

    Gutiérrez-Gutiérrez, Silvia C.; Coulon, Frédéric; Jiang, Ying; Wagland, Stuart

    2015-08-15

    Highlights: • Samples from multiple core drills were obtained from 4× landfill sites in the UK. • Each sample analysed for rare earth elements, critical metals and valuable metals. • Two stage microwave digestion method ensuring high yield. • High quantities of copper and aluminium were observed in the soil layers of landfill. • Across 4× landfills aluminium and copper present has a value of around $400 million. - Abstract: Rare earth elements (REEs), Platinum group metals (PGMs) and other critical metals currently attract significant interest due to the high risks of supply shortage and substantial impact on the economy. Their uses in many applications have made them present in municipal solid waste (MSW) and in commercial and industrial waste (C&I), since several industrial processes produce by-products with high content of these metals. With over 4000 landfills in the UK alone, the aim of this study was to assess the existence of these critical metals within landfills. Samples collected from four closed landfills in UK were subjected to a two-step acid digestion to extract 27 metals of interest. Concentrations across the four landfill sites were 58 ± 6 mg kg{sup −1} for REEs comprising 44 ± 8 mg kg{sup −1} for light REEs, 11 ± 2 mg kg{sup −1} for heavy REEs and 3 ± 1 mg kg{sup −1} for Scandium (Sc) and 3 ± 1.0 mg kg{sup −1} of PGMs. Compared to the typical concentration in ores, these concentrations are too low to achieve a commercially viable extraction. However, content of other highly valuable metals (Al and Cu) was found in concentrations equating to a combined value across the four landfills of around $400 million, which increases the economic viability of landfill mining. Presence of critical metals will mainly depend on the type of waste that was buried but the recovery of these metals through landfill mining is possible and is economically feasible only if additional materials (plastics, paper, metallic items and other) are

  4. Vibration analysis of single-walled carbon nanocones using multiscale atomistic finite element method incorporating Tersoff-Brenner potential

    NASA Astrophysics Data System (ADS)

    Gajbhiye, Sachin O.; Singh, S. P.

    2015-07-01

    This research work addresses the free and forced vibration characteristics of single-walled carbon nanocones (SWCNCs) using multiscale atomistic finite element method (AFEM) incorporating Tersoff-Brenner (TB) potential. The multibody interatomic TB potential is used to represent the energy between two carbon atoms. Based on the TB potential, new set of force constant parameters is established for carbon nanocones, and the equivalent geometric and elastic properties of the space frame element to represent carbon-carbon bond are derived which are consistent with the material constitutive relations. The eigenvalues of clamped and cantilevered SWCNCs with different disclination angles are extracted using AFEM, and the effect of these angles on the resonant frequencies is investigated. A computational sine sweep test is carried out on the atomic structure of SWCNCs within the frequency range of 0-10 THz to investigate the steady-state forced vibration response under harmonic excitation. The frequency response of the SWCNCs to the cyclic and impulse load over an applied frequency range is calculated. Based on the forced vibration response spectra, the resonant frequency components of SWCNCs are identified. The results have been validated using molecular dynamics simulation.

  5. Erosion/abrasion-preventing potential of NaF and F/Sn/chitosan toothpastes in dentine and impact of the organic matrix.

    PubMed

    Ganss, C; Klimek, J; Schlueter, N

    2014-01-01

    The study investigated the erosion/abrasion-preventing potential of experimental NaF (1,400 ppm F(-)) and amine fluoride (AmF)/NaF/SnCl2/chitosan (1,400 ppm F(-), 3,500 ppm Sn(2+), 0.5% chitosan) toothpastes relative to placebo and SnF2 gel (970 ppm F(-), 3,000 ppm Sn(2+)), and the impact of the demineralised dentine matrix on toothpaste effects. The study was a cyclic erosion/intervention experiment (10 days). Samples were stored in mineral salt solution either without or with collagenase (from Clostridium histolyticum type VII; 100 U/ml) for continuous removal of the organic matrix. To produce a comparable order of tissue loss, erosion was performed 6 × 30 s/day with 0.5% citric acid in the latter and 6 × 90 s/day with 1% citric acid in the former. Intervention was toothpaste slurry immersion (2 × 2 min/day); half of the samples were additionally brushed for 15 s within this time (brushing machine, load 200 g). Tissue loss was determined profilometrically (mean ± SD; µm). Tissue loss values (without/with brushing) for placebo, NaF, AmF/NaF/SnCl2/chitosan and SnF2 gel, respectively, were 11.6 ± 3.1/12.2 ± 2.5, 12.7 ± 3.1/10.7 ± 4.5, 8.7 ± 2.1/9.7 ± 2.1 and 8.8 ± 1.8/​10.9 ± 1.8 in the presence of the organic matrix and 10.7 ± 3.2/11.9 ± 2.1, 8.2 ± 4.0/10.1 ± 4.1, 8.7 ± 2.9/9.1 ± 1.8 and 8.4 ± 1.9/7.5 ± 1.5 in the absence of the organic matrix. Relative to placebo, the NaF formulation had no significant effects; the AmF/NaF/SnCl2/chitosan formulation significantly reduced tissue loss between 20 and 25% except when applied without brushing in the absence of the organic matrix. The effects of the formulations were similar both in the presence and absence of the organic matrix. Sn(2+)/F(-)-​containing formulations have the potential to reduce erosion/abrasion even in the absence of demineralised collagen; seeking for more effective formulations is desirable.

  6. Matrix Metalloproteinase 2 as a Potential Mediator of Vascular Smooth Muscle Cell Migration and Chronic Vascular Remodeling in Hypertension.

    PubMed

    Belo, V A; Guimarães, Danielle A; Castro, Michele Mazzaron

    2015-01-01

    For vascular remodeling in hypertension, it is essential that vascular smooth muscle cells (VSMCs) reshape in order to proliferate and migrate. The extracellular matrix (ECM) needs to be degraded to favor VSMC migration. Many proteases, including matrix metalloproteinases (MMPs), contribute to ECM proteolysis and VSMC migration. Bioactive peptides, hemodynamic forces and reactive oxygen-nitrogen species regulate MMP-2 expression and activity. Increased MMP-2 activity contributes to hypertension-induced maladaptive arterial changes and sustained hypertension. New ECM is synthesized to supply VSMCs with bioactive mediators, which stimulate hypertrophy. MMP-2 stimulates the interaction of VSMCs with newly formed ECM, which triggers intracellular signaling via integrins to induce a phenotypic switch and persistent migration. VSMCs switch from a contractile to a synthetic phenotype in order to migrate and contribute to vascular remodeling in hypertension. MMPs also disrupt growth factors bound to ECM, thus contributing to their capacity to regulate VSMC migration. This review sheds light on the proteolytic effects of MMP-2 on ECM and non-ECM substrates in the vasculature and how these effects contribute to VSMC migration in hypertension. The inhibition of MMP activity as a therapeutic target may make it possible to reduce arterial maladaptation caused by hypertension and prevent the resulting fatal cardiovascular events. PMID:26731549

  7. Rare earth elements and critical metal content of extracted landfilled material and potential recovery opportunities.

    PubMed

    Gutiérrez-Gutiérrez, Silvia C; Coulon, Frédéric; Jiang, Ying; Wagland, Stuart

    2015-08-01

    Rare earth elements (REEs), Platinum group metals (PGMs) and other critical metals currently attract significant interest due to the high risks of supply shortage and substantial impact on the economy. Their uses in many applications have made them present in municipal solid waste (MSW) and in commercial and industrial waste (C&I), since several industrial processes produce by-products with high content of these metals. With over 4000 landfills in the UK alone, the aim of this study was to assess the existence of these critical metals within landfills. Samples collected from four closed landfills in UK were subjected to a two-step acid digestion to extract 27 metals of interest. Concentrations across the four landfill sites were 58±6mgkg(-1) for REEs comprising 44±8mgkg(-1) for light REEs, 11±2mgkg(-1) for heavy REEs and 3±1mgkg(-1) for Scandium (Sc) and 3±1.0mgkg(-1) of PGMs. Compared to the typical concentration in ores, these concentrations are too low to achieve a commercially viable extraction. However, content of other highly valuable metals (Al and Cu) was found in concentrations equating to a combined value across the four landfills of around $400 million, which increases the economic viability of landfill mining. Presence of critical metals will mainly depend on the type of waste that was buried but the recovery of these metals through landfill mining is possible and is economically feasible only if additional materials (plastics, paper, metallic items and other) are also recovered for reprocessing.

  8. Rare earth elements and critical metal content of extracted landfilled material and potential recovery opportunities.

    PubMed

    Gutiérrez-Gutiérrez, Silvia C; Coulon, Frédéric; Jiang, Ying; Wagland, Stuart

    2015-08-01

    Rare earth elements (REEs), Platinum group metals (PGMs) and other critical metals currently attract significant interest due to the high risks of supply shortage and substantial impact on the economy. Their uses in many applications have made them present in municipal solid waste (MSW) and in commercial and industrial waste (C&I), since several industrial processes produce by-products with high content of these metals. With over 4000 landfills in the UK alone, the aim of this study was to assess the existence of these critical metals within landfills. Samples collected from four closed landfills in UK were subjected to a two-step acid digestion to extract 27 metals of interest. Concentrations across the four landfill sites were 58±6mgkg(-1) for REEs comprising 44±8mgkg(-1) for light REEs, 11±2mgkg(-1) for heavy REEs and 3±1mgkg(-1) for Scandium (Sc) and 3±1.0mgkg(-1) of PGMs. Compared to the typical concentration in ores, these concentrations are too low to achieve a commercially viable extraction. However, content of other highly valuable metals (Al and Cu) was found in concentrations equating to a combined value across the four landfills of around $400 million, which increases the economic viability of landfill mining. Presence of critical metals will mainly depend on the type of waste that was buried but the recovery of these metals through landfill mining is possible and is economically feasible only if additional materials (plastics, paper, metallic items and other) are also recovered for reprocessing. PMID:25957938

  9. Potential health concerns of trace elements and mineral content in commonly consumed greenhouse vegetables in Isfahan, Iran

    PubMed Central

    Abdi, Mohammad Reza; Rezaee-Ebrahim-Saraee, Khadijeh; Fard, Mehdi Rezvani; Baradaran-Ghahfarokhi, Milad

    2015-01-01

    Background: This study aimed to investigate the potential health concerns of trace elements and mineral content of commonly consumed greenhouse vegetables in Isfahan, Iran. Materials and Methods: Six kinds of greenhouse vegetables namely; Raphanus sativus (Radish), Cucumis sativus (Cucumber), Solanum lycopersicum (Tomato), green Capsicum annuum (Green bell pepper), yellow C. annuum (Yellow bell pepper), and red C. annuum (Red bell pepper) were collected from Isfahan greenhouses, between December 2012 and March 2013. The vegetables were analyzed in order to determine the concentrations of trace elements and trace minerals using instrumental neutron activation analysis (INAA). Results: The results of INAA showed that the concentrations of aluminum, bromine, cobalt, rubidium and strontium of these vegetables were varied from 7.2 to 28.4 mg/kg, 0.6–11.7 mg/kg, 0.1–0.5 mg/kg, 4.2–8.4 mg/kg, and 12.0–141.0 mg/kg, respectively. The trace mineral concentrations of As, Cr, Cs, Sc, Th, and U in all of the samples were less than the defined tolerable upper intake level. Conclusion: The results of this study revealed that considering the measured trace elements and mineral content levels, Isfahan greenhouse vegetables do not impose any serious health harmful effects for individuals in the studied area due to their meal consumptions. PMID:26605243

  10. Risk assessment of potentially toxic elements in agricultural soils and maize tissues from selected districts in Tanzania.

    PubMed

    Marwa, Ernest M M; Meharg, Andrew A; Rice, Clive M

    2012-02-01

    A field survey was conducted to investigate the contamination of potentially toxic elements (PTEs) arsenic (As), lead (Pb), chromium (Cr), and nickel (Ni) in Tanzanian agricultural soils and to evaluate their uptake and translocation in maize as proxy to the safety of maize used for human and animal consumption. Soils and maize tissues were sampled from 40 farms in Tanzania and analyzed using inductively coupled plasma-mass spectrometry in the United Kingdom. The results showed high levels of PTEs in both soils and maize tissues above the recommended limits. Nickel levels of up to 34.4 and 56.9mgkg(-1) respectively were found in some maize shoots and grains from several districts. Also, high Pb levels >0.2mgkg(-1) were found in some grains. The grains and shoots with high levels of Ni and Pb are unfit for human and animal consumption. Concentrations of individual elements in maize tissues and soils did not correlate and showed differences in uptake and translocation. However, Ni showed a more efficient transfer from soils to shoots than As, Pb and Cr. Transfer of Cr and Ni from shoots to grains was higher than other elements, implying that whatever amount is assimilated in maize shoots is efficiently mobilized and transferred to grains. Thus, the study recommended to the public to stop consuming and feeding their animals maize with high levels of PTEs for their safety. PMID:22226395

  11. Elemental Fingerprinting of Mussel Shells to Predict Population Sources and Redistribution Potential in the Gulf of Maine

    PubMed Central

    Sorte, Cascade J. B.; Etter, Ron J.; Spackman, Robert; Boyle, Elizabeth E.; Hannigan, Robyn E.

    2013-01-01

    As the climate warms, species that cannot tolerate changing conditions will only persist if they undergo range shifts. Redistribution ability may be particularly variable for benthic marine species that disperse as pelagic larvae in ocean currents. The blue mussel, Mytilus edulis, has recently experienced a warming-related range contraction in the southeastern USA and may face limitations to northward range shifts within the Gulf of Maine where dominant coastal currents flow southward. Thus, blue mussels might be especially vulnerable to warming, and understanding dispersal patterns is crucial given the species' relatively long planktonic larval period (>1 month). To determine whether trace elemental “fingerprints” incorporated in mussel shells could be used to identify population sources (i.e. collection locations), we assessed the geographic variation in shell chemistry of blue mussels collected from seven populations between Cape Cod, Massachusetts and northern Maine. Across this ∼500 km of coastline, we were able to successfully predict population sources for over two-thirds of juvenile individuals, with almost 80% of juveniles classified within one site of their collection location and 97% correctly classified to region. These results indicate that significant differences in elemental signatures of mussel shells exist between open-coast sites separated by ∼50 km throughout the Gulf of Maine. Our findings suggest that elemental “fingerprinting” is a promising approach for predicting redistribution potential of the blue mussel, an ecologically and economically important species in the region. PMID:24244724

  12. Matrix Embedded Organic Synthesis

    NASA Astrophysics Data System (ADS)

    Kamakolanu, U. G.; Freund, F. T.

    2016-05-01

    In the matrix of minerals such as olivine, a redox reaction of the low-z elements occurs. Oxygen is oxidized to the peroxy state while the low-Z-elements become chemically reduced. We assign them a formula [CxHyOzNiSj]n- and call them proto-organics.

  13. Baseline levels of potentially toxic elements in soils: a case study in Puren, La Araucania, Chile

    NASA Astrophysics Data System (ADS)

    Bech, Jaume; Roca, Núria; Tume, Pedro; Salazar, Ignacio; Martínez-Sánchez, Maria Jose; Pérez-Sirvent, Carmen

    2013-04-01

    The distribution patterns of element concentration are primarily influenced by the lithology of parent material, and secondly by the soil forming processes that modify the basic geochemical composition and redistribute the content of metals within the soil profile. To evaluate the heavy metal contamination in soils it is necessary to survey heavy metal background levels in order to understand their migration and distribution during pedogenesis. Four soil profiles of the forest area of Puren (IX region, Chile) have been investigated and the variability in the natural background of four metals (i.e., As, Cu, Mn and Zn) has been examined. Sampling sites with minimal anthropogenic influence were selected. Soil samples were collected from every horizon in each profile and samples were digested in Teflon vessels with concentrated HF and HNO3 acid solutions for the determination of total heavy metal concentrations. The Zn content was determined by flame atomic absorption spectrometry (FAAS). The Cu and Mn contents were determined by electrothermal atomization atomic absorption spectrometry (ETAAS). The As content was measured by atomic fluorescence spectrometry using an automated continuous flow hydride generation spectrometer (PSA for As). The range of total soil values in mgkg-1 is as follows: As 0.51 and 2.66; Cu: 4.00 and 32.10; Mn 373 and 1563; Zn 73.2 and 193.2 mg•kg-1, respectively. Soils had acid pH (5.2±0.5), organic matter contents ranging from 3.1 to 7.2 at surface, and decreases with depth (range 0.1-0.3). Cation exchange capacity (CEC) is generally high (average 38.4 cmol(+)•kg-1) at surface and decreases with depth (range 24.3-6.7). In this study, no association between heavy metals and organic carbon content was found. However, Cu and Mn was strongly positive correlated with CEC. Transformation and translocation of soil constituents as the clay illuviaton represent the soil forming processes that have greater relevance in the distribution of heavy

  14. Assessment of toxicity potential of metallic elements in discarded electronics: a case study of mobile phones in China.

    PubMed

    Wu, B Y; Chan, Y C; Middendorf, A; Gu, X; Zhong, H W

    2008-01-01

    The electronic waste (e-waste) is increasingly flooding Asia, especially China. E-waste could precipitate a growing volume of toxic input to the local environment if it was not handed properly. This makes the evaluation of environmental impact from electronics an essentially important task for the life cycle assessment (LCA) and the end-of-life management of electronic products. This study presented a quantitative investigation on the environmental performance of typical electronics. Two types of disposed mobile phones (MPs), as a representative of consumer electronics, were evaluated in terms of toxicity potential indicator (TPI) with an assumption of worst-case scenario. It is found that the composition and the percentages of constituents in MPs are similar. More than 20 metallic elements make up 35 wt.%-40 wt.% of the total weight, of which 12 elements are identified to be highly hazardous and 12 are less harmful. With the TPI technique, the environmental performance of Pb is attributed to be 20.8 mg(-1). The total TPIs of metallic elements in the old and new type MP is 255,403 and 127,639 units, respectively, which is equivalent to the effect of releasing 6.14 and 12.28 g Pb into the environment. The average TPI of the old and new type MP is 4.1 and 4.5 mg(-1), respectively, which suggests a similar eco-efficiency per unit mass. The new model of MP is more eco-effective than the old one, which is not due to a reduction in the type of hazardous elements, but rather due to a significant miniaturization of the package with less weight. A single MP can have a considerable toxicity to the environment as referred to Pb, which suggests a major concern for the environmental impact of the total e-waste with a huge quantity and a heavy mass in China.

  15. Natural Selection and Functional Potentials of Human Noncoding Elements Revealed by Analysis of Next Generation Sequencing Data.

    PubMed

    Jha, Pankaj; Lu, Dongsheng; Xu, Shuhua

    2015-01-01

    Noncoding DNA sequences (NCS) have attracted much attention recently due to their functional potentials. Here we attempted to reveal the functional roles of noncoding sequences from the point of view of natural selection that typically indicates the functional potentials of certain genomic elements. We analyzed nearly 37 million single nucleotide polymorphisms (SNPs) of Phase I data of the 1000 Genomes Project. We estimated a series of key parameters of population genetics and molecular evolution to characterize sequence variations of the noncoding genome within and between populations, and identified the natural selection footprints in NCS in worldwide human populations. Our results showed that purifying selection is prevalent and there is substantial constraint of variations in NCS, while positive selectionis more likely to be specific to some particular genomic regions and regional populations. Intriguingly, we observed larger fraction of non-conserved NCS variants with lower derived allele frequency in the genome, indicating possible functional gain of non-conserved NCS. Notably, NCS elements are enriched for potentially functional markers such as eQTLs, TF motif, and DNase I footprints in the genome. More interestingly, some NCS variants associated with diseases such as Alzheimer's disease, Type 1 diabetes, and immune-related bowel disorder (IBD) showed signatures of positive selection, although the majority of NCS variants, reported as risk alleles by genome-wide association studies, showed signatures of negative selection. Our analyses provided compelling evidence of natural selection forces on noncoding sequences in the human genome and advanced our understanding of their functional potentials that play important roles in disease etiology and human evolution.

  16. Generation of priming mesenchymal stem cells with enhanced potential to differentiate into specific cell lineages using extracellular matrix proteins.

    PubMed

    Han, Na Rae; Yun, Jung Im; Park, Young Hyun; Ahn, Ji Yeon; Kim, Choonghyo; Choi, Jung Hoon; Lee, Eunsong; Lim, Jeong Mook; Lee, Seung Tae

    2013-07-01

    Poor understanding of the differentiation of mesenchymal stem cells (MSCs) has resulted in a low differentiation yield, and has hindered their application in medicine. As a solution, priming MSCs sensitive to signaling, thus stimulating differentiation into a specific cell lineage, may improve the differentiation yield. To demonstrate this, priming MSCs were produced by using a gelatin matrix for the isolation of primary MSCs from bone-marrow-derived primary cells. Subsequently, cellular characteristics and sensitivity to specific differentiation signals were analyzed at passage five. Compared to non-priming MSCs, priming MSCs showed no significant differences in cellular characteristics, but demonstrated a significant increase in sensitivity to neurogenic differentiation signals. These results demonstrate that generation of priming MSCs by specific extracellular signaling increases the rate of differentiation into a cell-specific lineage.

  17. Negative regulatory element associated with potentially functional promoter and enhancer elements in the long terminal repeats of endogenous murine leukemia virus-related proviral sequences.

    PubMed Central

    Ch'ang, L Y; Yang, W K; Myer, F E; Yang, D M

    1989-01-01

    Three series of recombinant DNA clones were constructed, with the bacterial chloramphenicol acetyltransferase (CAT) gene as a quantitative indicator, to examine the activities of promoter and enhancer sequence elements in the 5' long terminal repeat (LTR) of murine leukemia virus (MuLV)-related proviral sequences isolated from the mouse genome. Transient CAT expression was determined in mouse NIH 3T3, human HT1080, and mink CCL64 cultured cells transfected with the LTR-CAT constructs. The 700-base-pair (bp) LTRs of three polytropic MuLV-related proviral clones and the 750-bp LTRs of four modified polytropic proviral clones, in complete structures either with or without the adjacent downstream sequences, all showed very little or negligible activities for CAT expression, while ecotropic MuLV LTRs were highly active. The MuLV-related LTRs were divided into three portions and examined separately. The 3' portion of the MuLV-related LTRs that contains the CCAAC and TATAA boxes was found to be a functional promoter, being about one-half to one-third as active as the corresponding portion of ecotropic MuLV LTRs. A MboI-Bg/II fragment, representing the distinct 190- to 200-bp inserted segment in the middle, was found to be a potential enhancer, especially when examined in combination with the simian virus 40 promoter in CCL64 cells. A PstI-MboI fragment of the 5' portion, which contains the protein-binding motifs of the enhancer segment as well as the upstream LTR sequences, showed moderate enhancer activities in CCL6 cells but was virtually inactive in NIH 3T3 cells and HT1080 cells; addition of this fragment to the ecotropic LTR-CAT constructs depressed CAT expression. Further analyses using chimeric LTR constructs located the presence of a strong negative regulatory element within the region containing the 5' portion of the enhancer and the immediate upstream sequences in the MuLV-related LTRs. Images PMID:2542587

  18. Concentration of potentially toxic elements in field crops grown near and far from cities of the Pampas (Argentina).

    PubMed

    Lavado, Raúl S

    2006-07-01

    Soils of the Pampas show no signs of contamination with potentially toxic elements (PTEs), except in the areas that surround cities. The concentration of PTE in crops grown in this region is in most cases unknown. Our objective was to determine the PTE concentration in main field crops and pastures grown in 'a priori' non-contaminated areas and in potentially contaminated areas around cities. Forty-eight plots from farms located far from cities or roads and 36 plots from farms located very close to cities or to high traffic roads were sampled. The area ranged from 33 degrees 40' S to 36 degrees 0' S and from 57 degrees 35' W to 61 degrees 22' W. Maize, soybean, wheat, grazed grassland and pastures, and their top soils were sampled. All samples were acid digested. Cadmium, zinc, chromium, copper, nickel and lead were determined using ICPES. Standard t-tests were performed. All soils were within the known normal values of soil PTE concentrations, with the exception of a few cases around cities. PTE accumulation on grains and aerial biomass is considered almost negligible in crops grown in both studied areas, with the exception of a few elements in soybean. PTE concentrations in crops and pastures are in keeping with the low content of trace metals found in soils of the Pampas.

  19. Structures, Bonding, and Energetics of Potential Triatomic Circumstellar Molecules Containing Group 15 and 16 Elements.

    PubMed

    Turner, Walter E; Agarwal, Jay; Schaefer, Henry F

    2015-12-01

    The recent discovery of PN in the oxygen-rich shell of the supergiant star VY Canis Majoris points to the formation of several triatomic molecules involving oxygen, nitrogen, and phosphorus; these are also intriguing targets for main-group synthetic inorganic chemistry. In this research, high-level ab initio electronic structure computations were conducted on the potential circumstellar molecule OPN and several of its heavier group 15 and 16 congeners (SPN, SePN, TePN, OPP, OPAs, and OPSb). For each congener, four isomers were examined. Optimized geometries were obtained with coupled cluster theory [CCSD(T)] using large Dunning basis sets [aug-cc-pVQZ, aug-cc-pV(Q+d)Z, and aug-cc-pVQZ-PP], and relative energies were determined at the complete basis set limit of CCSDT(Q) from focal point analyses. The linear phosphorus-centered molecules were consistently the lowest in energy of the group 15 congeners by at least 6 kcal mol(-1), resulting from double-triple and single-double bond resonances within the molecule. The linear nitrogen-centered molecules were consistently the lowest in energy of the group 16 congeners by at least 5 kcal mol(-1), due to the electronegative central nitrogen atom encouraging electron delocalization throughout the molecule. For OPN, OPP, and SPN, anharmonic vibrational frequencies and vibrationally corrected rotational constants are predicted; good agreement with available experimental data is observed.

  20. Structures, Bonding, and Energetics of Potential Triatomic Circumstellar Molecules Containing Group 15 and 16 Elements.

    PubMed

    Turner, Walter E; Agarwal, Jay; Schaefer, Henry F

    2015-12-01

    The recent discovery of PN in the oxygen-rich shell of the supergiant star VY Canis Majoris points to the formation of several triatomic molecules involving oxygen, nitrogen, and phosphorus; these are also intriguing targets for main-group synthetic inorganic chemistry. In this research, high-level ab initio electronic structure computations were conducted on the potential circumstellar molecule OPN and several of its heavier group 15 and 16 congeners (SPN, SePN, TePN, OPP, OPAs, and OPSb). For each congener, four isomers were examined. Optimized geometries were obtained with coupled cluster theory [CCSD(T)] using large Dunning basis sets [aug-cc-pVQZ, aug-cc-pV(Q+d)Z, and aug-cc-pVQZ-PP], and relative energies were determined at the complete basis set limit of CCSDT(Q) from focal point analyses. The linear phosphorus-centered molecules were consistently the lowest in energy of the group 15 congeners by at least 6 kcal mol(-1), resulting from double-triple and single-double bond resonances within the molecule. The linear nitrogen-centered molecules were consistently the lowest in energy of the group 16 congeners by at least 5 kcal mol(-1), due to the electronegative central nitrogen atom encouraging electron delocalization throughout the molecule. For OPN, OPP, and SPN, anharmonic vibrational frequencies and vibrationally corrected rotational constants are predicted; good agreement with available experimental data is observed. PMID:26566183

  1. Possibilities and potential roles of the functional peptides based on enamel matrix proteins in promoting the remineralization of initial enamel caries.

    PubMed

    Ieong, Cheng Cheng; Zhou, Xue Dong; Li, Ji Yao; Li, Wei; Zhang, Ling Lin

    2011-03-01

    Dental caries is the most common oral diseases, and it gives a serious threat to oral and general health. Fluoride, a classic anti-caries agent, has a profound effect on caries prevention and treatment. However, fluorosis and fluoride-resistant strains limit the further application of fluoride treatment. Therefore, it is still of significant benefit to seek alternatives, bringing more effective anti-caries agents. The potential role of enamel matrix proteins(EMPs) in promoting the regeneration of periodontal tissue and inducing bone have been proved. EMPs have been successfully applied in the field of periodontal disease and dental implants in recent years. Previous researches revealed that enamel matrix proteins had an important role in the synthesis of hydroxyapatite in vitro. Some experiments about the degeneration or removal of EMP suggest that enamel matrix proteins are related to the occurrence and development of caries. Based on evidences illustrated by these experiments, this paper hypothesizes that functional peptides based on the function and structure of EMPs could promote remineralization of enamel caries, which could perform as a suitable treatment to enamel caries. The hypothesis may lead a new direction in the study on the prevention and treatment of enamel caries, and further study of the anti-caries mechanisms of EMP will enable researchers to find out the most effective anti-caries peptides, which could be developed into a bionics anti-cariogenic agent.

  2. Water clusters in an argon matrix: infrared spectra from molecular dynamics simulations with a self-consistent charge density functional-based tight binding/force-field potential.

    PubMed

    Simon, Aude; Iftner, Christophe; Mascetti, Joëlle; Spiegelman, Fernand

    2015-03-19

    The present theoretical study aims at investigating the effects of an argon matrix on the structures, energetics, dynamics, and infrared (IR) spectra of small water clusters (H2O)n (n = 1-6). The potential energy surface is obtained from a hybrid self-consistent charge density functional-based tight binding/force-field approach (SCC-DFTB/FF) in which the water clusters are treated at the SCC-DFTB level and the matrix is modeled at the FF level by a cluster consisting of ∼340 Ar atoms with a face centered cubic (fcc) structure, namely (H2O)n/Ar. With respect to a pure FF scheme, this allows a quantum description of the molecular system embedded in the matrix, along with all-atom geometry optimization and molecular dynamics (MD) simulations of the (H2O)n/Ar system. Finite-temperature IR spectra are derived from the MD simulations. The SCC-DFTB/FF scheme is first benchmarked on (H2O)Arn clusters against correlated wave function results and DFT calculations performed in the present work, and against FF data available in the literature. Regarding (H2O)n/Ar systems, the geometries of the water clusters are found to adapt to the fcc environment, possibly leading to intermolecular distortion and matrix perturbation. Several energetical quantities are estimated to characterize the water clusters in the matrix. In the particular case of the water hexamer, substitution and insertion energies for the prism, bag, and cage are found to be lower than that for the 6-member ring isomer. Finite-temperature MD simulations show that the water monomer has a quasifree rotation motion at 13 K, in agreement with experimental data. In the case of the water dimer, the only large-amplitude motion is a distortion-rotation intermolecular motion, whereas only vibration motions around the nuclei equilibrium positions are observed for clusters with larger sizes. Regarding the IR spectra, we find that the matrix environment leads to redshifts of the stretching modes and almost no shift of the

  3. Water clusters in an argon matrix: infrared spectra from molecular dynamics simulations with a self-consistent charge density functional-based tight binding/force-field potential.

    PubMed

    Simon, Aude; Iftner, Christophe; Mascetti, Joëlle; Spiegelman, Fernand

    2015-03-19

    The present theoretical study aims at investigating the effects of an argon matrix on the structures, energetics, dynamics, and infrared (IR) spectra of small water clusters (H2O)n (n = 1-6). The potential energy surface is obtained from a hybrid self-consistent charge density functional-based tight binding/force-field approach (SCC-DFTB/FF) in which the water clusters are treated at the SCC-DFTB level and the matrix is modeled at the FF level by a cluster consisting of ∼340 Ar atoms with a face centered cubic (fcc) structure, namely (H2O)n/Ar. With respect to a pure FF scheme, this allows a quantum description of the molecular system embedded in the matrix, along with all-atom geometry optimization and molecular dynamics (MD) simulations of the (H2O)n/Ar system. Finite-temperature IR spectra are derived from the MD simulations. The SCC-DFTB/FF scheme is first benchmarked on (H2O)Arn clusters against correlated wave function results and DFT calculations performed in the present work, and against FF data available in the literature. Regarding (H2O)n/Ar systems, the geometries of the water clusters are found to adapt to the fcc environment, possibly leading to intermolecular distortion and matrix perturbation. Several energetical quantities are estimated to characterize the water clusters in the matrix. In the particular case of the water hexamer, substitution and insertion energies for the prism, bag, and cage are found to be lower than that for the 6-member ring isomer. Finite-temperature MD simulations show that the water monomer has a quasifree rotation motion at 13 K, in agreement with experimental data. In the case of the water dimer, the only large-amplitude motion is a distortion-rotation intermolecular motion, whereas only vibration motions around the nuclei equilibrium positions are observed for clusters with larger sizes. Regarding the IR spectra, we find that the matrix environment leads to redshifts of the stretching modes and almost no shift of the

  4. Identification of potential sources and source regions of fine ambient particles measured at Gosan background site in Korea using advanced hybrid receptor model combined with positive matrix factorization - article no. D22217

    SciTech Connect

    Han, J.S.; Moon, K.J.; Kim, Y.J.

    2006-11-15

    The size- and time-resolved measurement of particulate trace elements was made using an eight-stage Davis Rotating Unit for Monitoring sampler and synchrotron X-ray fluorescence system from 29 March to 29 May in 2002 at Gosan, Korea, which is one of the representative background sites in east Asia. A sa result, continuous 3-hour average concentrations were obtained for 19 elements including S, Si, Al, Fe, Ca, Cl, Cu, Zn, Ti, K, Mn, Pb, Ni, V, Se, As, Rb, Cr, and Br. Positive matrix factorization (PMF) method was applied to the size-resolved aerosol data sets in order to identify the possible sources and to estimate their contribution to particulate matter mass in each size range. Twelve sources were then resolved in the fine size range ( 0.07 to 1.15 {mu}m), including continental aerosol, biomass burning, coal combustion, oil heating furnace, residual oil-fired boiler, municipal incineration, nonferrous metal source, ferrous metal source, gasoline vehicle, diesel vehicle, copper smelter, and volcanic emission. A newly developed hybrid receptor model, concentration, retention time, and source emission weighted trajectory (CRSWT) was then applied to the source intensities derived from the PMF analysis by incorporating meteorological and source inventory information of the study region in order to suggest the regional information of long-range transported fine aerosol sources. The CRSWT model was able to resolve highly potential source areas and pathways for the fine ambient aerosol at the Gosan background site.

  5. Fluvial geomorphic elements in modern sedimentary basins and their potential preservation in the rock record: A review

    NASA Astrophysics Data System (ADS)

    Weissmann, G. S.; Hartley, A. J.; Scuderi, L. A.; Nichols, G. J.; Owen, A.; Wright, S.; Felicia, A. L.; Holland, F.; Anaya, F. M. L.

    2015-12-01

    Since tectonic subsidence in sedimentary basins provides the potential for long-term facies preservation into the sedimentary record, analysis of geomorphic elements in modern continental sedimentary basins is required to understand facies relationships in sedimentary rocks. We use a database of over 700 modern sedimentary basins to characterize the fluvial geomorphology of sedimentary basins. Geomorphic elements were delineated in 10 representative sedimentary basins, focusing primarily on fluvial environments. Elements identified include distributive fluvial systems (DFS), tributive fluvial systems that occur between large DFS or in an axial position in the basin, lacustrine/playa, and eolian environments. The DFS elements include large DFS (> 30 km in length), small DFS (< 30 km in length), coalesced DFS in bajada or piedmont plains, and incised DFS. Our results indicate that over 88% of fluvial deposits in the evaluated sedimentary basins are present as DFS, with tributary systems covering a small portion (1-12%) of the basin. These geomorphic elements are commonly arranged hierarchically, with the largest transverse rivers forming large DFS and smaller transverse streams depositing smaller DFS in the areas between the larger DFS. These smaller streams commonly converge between the large DFS, forming a tributary system. Ultimately, most transverse rivers become tributary to the axial system in the sedimentary basin, with the axial system being confined between transverse DFS entering the basin from opposite sides of the basin, or a transverse DFS and the edge of the sedimentary basin. If axial systems are not confined by transverse DFS, they will form a DFS. Many of the world's largest rivers are located in the axial position of some sedimentary basins. Assuming uniformitarianism, sedimentary basins from the past most likely had a similar configuration of geomorphic elements. Facies distributions in tributary positions and those on DFS appear to display

  6. Potential use of a polycarbonate-urethane matrix reinforced with polyethylene fibers for shock-absorbing dental implants.

    PubMed

    Sheikhhassani, Ramtin; Anvari, Pasha; Taei, Simin; Sheikhhassani, Yasmin

    2015-09-01

    The absence of a shock-absorbing mechanism in commercial dental implants is a likely factor in the resulting bone loss and possible implant failure. The aim of the current study is to generate a shock-absorbing dental implant that resembles the periodontal ligament, which naturally absorbs occlusal overloading forces. To achieve this, a polycarbonate-urethane composite reinforced with polyethylene fibers will be constructed. Tests based on finite element analysis and mechanical testing are proposed to further examine this novel implant type.

  7. Search for the Standard Model Higgs Boson associated with a W Boson using Matrix Element Technique in the CDF detector at the Tevatron

    SciTech Connect

    Gonzalez, Barbara Alvarez

    2010-05-01

    method used to estimate the background contribution. The Matrix Element method, that was successfully used in the single top discovery analysis and many other analyses within the CDF collaboration, is the multivariate technique used in this thesis to discriminate signal from background events. With this technique is possible to calculate a probability for an event to be classified as signal or background. These probabilities are then combined into a discriminant function called the Event Probability Discriminant, EPD, which increases the sensitivity of the WH process. This method is described in detail in Chapter 7. As no evidence for the signal has been found, the results obtained with this work are presented in Chapter 8 in terms of exclusion regions as a function of the mass of the Higgs boso, taking into account the full systematics. The conclusions of this work to obtain the PhD are presnted in Chapter 9.

  8. Property Evaluation and Damage Evolution of Environmental Barrier Coatings and Environmental Barrier Coated SiC/SiC Ceramic Matrix Composite Sub-Elements

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Halbig, Michael; Jaskowiak, Martha; Hurst, Janet; Bhatt, Ram; Fox, Dennis S.

    2014-01-01

    This paper describes recent development of environmental barrier coatings on SiC/SiC ceramic matrix composites. The creep and fatigue behavior at aggressive long-term high temperature conditions have been evaluated and highlighted. Thermal conductivity and high thermal gradient cyclic durability of environmental barrier coatings have been evaluated. The damage accumulation and complex stress-strain behavior environmental barrier coatings on SiCSiC ceramic matrix composite turbine airfoil subelements during the thermal cyclic and fatigue testing of have been also reported.

  9. Biological effect of Acidithiobacillus thiooxidans on some potentially toxic elements during alteration of SON 68 nuclear glass

    NASA Astrophysics Data System (ADS)

    Bachelet, M.; Crovisier, J. L.; Stille, P.; Vuilleumier, S.; Geoffroy, V.

    2009-04-01

    Although underground nuclear waste repositories are not expected to be favourable places for microbial activity, one should not exclude localized action of extremophilic bacteria on some materials involved in the storage concept. Among endogenous or accidentally introduced acidophiles, some are susceptible to lead to a locally drastic decreased in pH, with potential consequences on materials corrosion. Experiments were performed with Acidithiobacillus thiooxidans on 100-125 m french reference nuclear glass SON68 grains in a mineral medium under static conditions during 60 days at 25degC. Growth medium was periodically renewed and analyzed by ICP-AES and ICP-MS spectrometry for both major, trace and ultra-trace elements. Biofilm formation was evidenced by confocal laser microscopy, staining DNA with ethidium bromide and exopolysaccharides with calcofluor white. Biofilm thickness around material grains exceeded 20 m under the chosen experimental conditions. It can be noticed that while numerous studies on biofilm formation upon interaction between Acidithiobacillus ferrooxidans and materials are found in the literature, evidence for biofilm formation is still scarce for the case of the acidophilic bacterium A. thiooxidans. Presence of biofilm is a key parameter for material alteration at the solid/solution interface in biotic systems. Indeed, various constitutive elements of materials trapped in the polyanionic polymer of biofilm may also influence the alteration process. In particular, biofilm may reduce the alteration rate of materials by forming a protective barrier at their surface (Aouad et al., 2008). In this study, glass alteration rates, determined using strontium as tracer, showed that the progressive formation of a biofilm on the surface of glass has a protective effect against its alteration. Uranium and rare earth elements (REE) are efficiently trapped in the biogenic compartment of the system (exopolysaccharides + bacterial cells). Besides, the ratio

  10. Transient finite element method using edge elements for moving conductor

    SciTech Connect

    Tani, Koji; Nishio, Takayuki; Yamada, Takashi ); Kawase, Yoshihiro . Dept. of Information Science)

    1999-05-01

    For the next generation of high speed railway systems and automobiles new braking systems are currently under development. These braking systems take into account the eddy currents, which are produced by the movement of the conductor in the magnetic field. For their optimum design, it is necessary to know the distribution of eddy currents in the moving conductor. The finite element method (FEM) is often used to simulate them. Here, transient finite element method using edge elements for moving conductor is presented. Here the magnetic vector potential is interpolated at the upwind position and the time derivative term is discretized by the backward difference method. As a result, the system matrix becomes symmetric and the ICCG method is applicable to solve the matrix. This method is used to solve an eddy current rail brake system. The results demonstrate that this approach is suitable to solve transient problems involving movement.

  11. A Novel Compound Rasatiol Isolated from Raphanus sativus Has a Potential to Enhance Extracellular Matrix Synthesis in Dermal Fibroblasts

    PubMed Central

    Roh, Seok-Seon; Park, Seung-Bae; Park, Seong-Mo; Choi, Byoung Wook; Lee, Min-Ho; Hwang, Yul-Lye; Kim, Chang Hun; Jeong, Hyun-Ah; Kim, Chang Deok

    2013-01-01

    Background The fibrous proteins of extracellular matrix (ECM) produced by dermal fibroblast contributes to the maintenance of connective tissue integrity. Objective This study is carried out to identify the bioactive ingredient from natural products that enhances ECM production in dermal fibroblasts. Methods Bioassay-directed fractionation was used to isolate the active ingredient from natural extracts. The effects of rasatiol (isolated from Raphanus sativus) on ECM production in primary cultured human dermal fibroblasts was investigated by enzyme linked immunosorbent assay and western blot analysis. Results Rasatiol accelerated fibroblast growth in a dose-dependent manner and increased the production of type 1 collagen, fibronectin and elastin. Phosphorylation of p42/44 extracellular signal-regulated kinase, p38 mitogen-activated protein kinase, and Akt was remarkably increased by rasatiol, indicating that enhanced ECM production is linked to the activation of intracellular signaling cascades. Conclusion These results indicate that rasatiol stimulates the fibrous components of ECM production, and may be applied to the maintenance of skin texture. PMID:24003274

  12. Nonorthogonal orbital based N-body reduced density matrices and their applications to valence bond theory. II. An efficient algorithm for matrix elements and analytical energy gradients in VBSCF method.

    PubMed

    Chen, Zhenhua; Chen, Xun; Wu, Wei

    2013-04-28

    In this paper, by applying the reduced density matrix (RDM) approach for nonorthogonal orbitals developed in the first paper of this series, efficient algorithms for matrix elements between VB structures and energy gradients in valence bond self-consistent field (VBSCF) method were presented. Both algorithms scale only as nm(4) for integral transformation and d(2)n(β)(2) for VB matrix elements and 3-RDM evaluation, while the computational costs of other procedures are negligible, where n, m, d, and n(β )are the numbers of variable occupied active orbitals, basis functions, determinants, and active β electrons, respectively. Using tensor properties of the energy gradients with respect to the orbital coefficients presented in the first paper of this series, a partial orthogonal auxiliary orbital set was introduced to reduce the computational cost of VBSCF calculation in which orbitals are flexibly defined. Test calculations on the Diels-Alder reaction of butadiene and ethylene have shown that the novel algorithm is very efficient for VBSCF calculations. PMID:23635124

  13. Surface-Deacetylated Chitin Nano-Fiber/Hyaluronic Acid Composites as Potential Antioxidative Compounds for Use in Extended-Release Matrix Tablets

    PubMed Central

    Anraku, Makoto; Tabuchi, Ryo; Ifuku, Shinsuke; Ishiguro, Takako; Iohara, Daisuke; Hirayama, Fumitoshi

    2015-01-01

    In this study, we examined a possible use of a surface-deacetylated chitin nano-fiber (SDCH-NF) and hyaluronic acid (HA) interpolymer complex (IPC) tablet as a potential antioxidative compound in extended-release matrix tablets. The antioxidant properties of untreated chitin (UCH), SDCH-NF, and HA were examined using N-centered radicals derived from 1,1′-diphenyl-2-picrylhydrazyl (DPPH) and 2,2′-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS). SDCH-NF and HA had acceptable scavenging abilities and were relatively efficient radical scavengers, but UCH was much less effective. The results suggest that SDCH-NF and HA could serve as scavengers of compounds related to the development of oxidative stress. An SDCH-NF/HA IPC tablet was prepared and evaluated as an extended-release tablet matrix using famotidine (FMT) as a model drug. The release of FMT from the IPC tablet (DCF-NF:HA = 1:1) was slower than that from a SDCH-NF only tablet. Turbidity measurements and X-ray diffraction (XRD) data also indicated that the optimum complexation ratio for IPC between SDCH-NF/HA is 1/1, resulting in a good relationship between turbidity or XRD of the complex and the release ratio of FMT. These results suggest that an SDCH-NF/HA tablet has the potential for use in an extended-release IPC tablet with a high antioxidant activity. PMID:26501272

  14. Harmful potential toxic elements in greenhouse soils under long-term cultivation in Almería (Spain)

    NASA Astrophysics Data System (ADS)

    Joaquin Ramos-Miras, Jose; Rodríguez Martín, Jose Antonio; Boluda, Rafael; Bech, Jaume; Gil, Carlos

    2014-05-01

    Heavy metals (HM) are considered highly significant environmental contaminants and are the object of many scientific research works into the soil environment. Activities like agriculture or industry can increase the concentration of these contaminants in soils and waters, which can affect the food chain. Intensification of certain agricultural practices, constant and excessive use of fertilizers and phytosanitary products, and using machinery, increase the HM content in agricultural soils. Many studies have dealt with HM accumulation over time. Despite these works, the influence of long periods of time on these contents, the dynamics and evolution of these elements in agricultural soils, especially soils used for intensive farming purposes under greenhouse conditions, remain unknown to a certain extent. The western Almería region (Spain) is a very important area from both the socio-economic and agricultural viewpoints. A common practice in greenhouse agriculture is the addition of agrochemicals to soils and crops to improve nutrient supply or crop protection and disease control. Such intense agricultural activity has a strong impact, which may have negative repercussions on both these greenhouse soils and the environment. A research has been carried out to determine the total and available levels of six harmful potentially toxic elements (Cd, Cu, Pb, Ni, Zn and Co), and to assess long-term variations in the greenhouse soils of western Almeria. The results indicate that managing soils in the greenhouse preparation stage determines major changes in total and available HM contents. Furthermore, Cd, Cu and Pb enrichment in soil was observed depending on the element and years of growth.

  15. The comparison of element partitioning in two types of thermal treatment facilities and the effects on potential radiation dose

    SciTech Connect

    Aaberg, R.L.; Burger, L.L.; Baker, D.A.; Wallo, A. III; Vazquez, G.A.; Beck, W.L.

    1995-05-01

    The US Department of Energy (DOE) is performing a technical analysis to support the potential development of risk-based, numerical radiological control criteria (RCC) for mixed waste from DOE operations. As part of the technical analysis, potential future radiation doses are being calculated for workers at thermal treatment facilities and members of the public residing near such facilities. This study compared two types of thermal treatment systems: a conventional combustion chamber with excess air, represented by a rotary kiln with afterburner, and an oxygen-deficient pyrolysis unit, represented by a plasma arc furnace. The purpose of the first part of this study is to estimate the partitioning for significant radionuclides and elements in the two types of thermal treatment systems. Excess-air systems are generally found to produce heavy-metal chlorides, oxides, and sulfates; plasma-arc systems tend to produce more volatile free metals. This difference causes a change in source term dominance from halide volatility to free metal volatility. Chemical thermodynamic methodology is used to estimate partitioning in the two treatment systems. The second part of the study examines how the potential radiation dose to workers handling residue materials is affected by partitioning of radionuclides at the different types of facilities.

  16. Matrix Metalloproteinase (MMP) Proteolysis of the Extracellular Loop of Voltage-gated Sodium Channels and Potential Alterations in Pain Signaling*

    PubMed Central

    Remacle, Albert G.; Kumar, Sonu; Motamedchaboki, Khatereh; Cieplak, Piotr; Hullugundi, Swathi; Dolkas, Jennifer; Shubayev, Veronica I.; Strongin, Alex Y.

    2015-01-01

    Congenital insensitivity to pain (CIP) or congenital analgesia is a rare monogenic hereditary condition. This disorder is characterized by the inability to perceive any form of pain. Nonsense mutations in Nav.1.7, the main pain signaling voltage-gated sodium channel, lead to its truncations and, consequently, to the inactivation of the channel functionality. However, a non-truncating homozygously inherited missense mutation in a Bedouin family with CIP (Nav1.7-R907Q) has also been reported. Based on our currently acquired in-depth knowledge of matrix metalloproteinase (MMP) cleavage preferences, we developed the specialized software that predicts the presence of the MMP cleavage sites in the peptide sequences. According to our in silico predictions, the peptide sequence of the exposed extracellular unstructured region linking the S5–S6 transmembrane segments in the DII domain of the human Nav1.7 sodium channel is highly sensitive to MMP-9 proteolysis. Intriguingly, the CIP R907Q mutation overlaps with the predicted MMP-9 cleavage site sequence. Using MMP-9 proteolysis of the wild-type, CIP, and control peptides followed by mass spectrometry of the digests, we demonstrated that the mutant sequence is severalfold more sensitive to MMP-9 proteolysis relative to the wild type. Because of the substantial level of sequence homology among sodium channels, our data also implicate MMP proteolysis in regulating the cell surface levels of the Nav1.7, Nav1.6, and Nav1.8 channels, but not Nav1.9. It is likely that the aberrantly accelerated MMP-9 proteolysis during neurogenesis is a biochemical rational for the functional inactivation in Nav1.7 and that the enhanced cleavage of the Nav1.7-R907Q mutant is a cause of CIP in the Bedouin family. PMID:26283785

  17. Matrix Metalloproteinase (MMP) Proteolysis of the Extracellular Loop of Voltage-gated Sodium Channels and Potential Alterations in Pain Signaling.

    PubMed

    Remacle, Albert G; Kumar, Sonu; Motamedchaboki, Khatereh; Cieplak, Piotr; Hullugundi, Swathi; Dolkas, Jennifer; Shubayev, Veronica I; Strongin, Alex Y

    2015-09-18

    Congenital insensitivity to pain (CIP) or congenital analgesia is a rare monogenic hereditary condition. This disorder is characterized by the inability to perceive any form of pain. Nonsense mutations in Nav.1.7, the main pain signaling voltage-gated sodium channel, lead to its truncations and, consequently, to the inactivation of the channel functionality. However, a non-truncating homozygously inherited missense mutation in a Bedouin family with CIP (Nav1.7-R907Q) has also been reported. Based on our currently acquired in-depth knowledge of matrix metalloproteinase (MMP) cleavage preferences, we developed the specialized software that predicts the presence of the MMP cleavage sites in the peptide sequences. According to our in silico predictions, the peptide sequence of the exposed extracellular unstructured region linking the S5-S6 transmembrane segments in the DII domain of the human Nav1.7 sodium channel is highly sensitive to MMP-9 proteolysis. Intriguingly, the CIP R907Q mutation overlaps with the predicted MMP-9 cleavage site sequence. Using MMP-9 proteolysis of the wild-type, CIP, and control peptides followed by mass spectrometry of the digests, we demonstrated that the mutant sequence is severalfold more sensitive to MMP-9 proteolysis relative to the wild type. Because of the substantial level of sequence homology among sodium channels, our data also implicate MMP proteolysis in regulating the cell surface levels of the Nav1.7, Nav1.6, and Nav1.8 channels, but not Nav1.9. It is likely that the aberrantly accelerated MMP-9 proteolysis during neurogenesis is a biochemical rational for the functional inactivation in Nav1.7 and that the enhanced cleavage of the Nav1.7-R907Q mutant is a cause of CIP in the Bedouin family. PMID:26283785

  18. Mannose-binding lectin (MBL) mutants are susceptible to matrix metalloproteinase proteolysis: potential role in human MBL deficiency.

    PubMed

    Butler, Georgina S; Sim, Derek; Tam, Eric; Devine, Dana; Overall, Christopher M

    2002-05-17

    Mannose-binding lectin (MBL) plays a critical role in innate immunity. Point mutations in the collagen-like domain (R32C, G34D, or G37E) of MBL cause a serum deficiency, predisposing patients to infections and diseases such as rheumatoid arthritis. We examined whether MBL mutants show enhanced susceptibility to proteolysis by matrix metalloproteinases (MMPs), which are important mediators in inflammatory tissue destruction. Human and rat MBL were resistant to proteolysis in the native state but were cleaved selectively within the collagen-like domain by multiple MMPs after heat denaturation. In contrast, rat MBL with mutations homologous to those of the human variants (R23C, G25D, or G28E) was cleaved efficiently without denaturation in the collagen-like domain by MMP-2 and MMP-9 (gelatinases A and B) and MMP-14 (membrane type-1 MMP), as well as by MMP-1 (collagenase-1), MMP-8 (neutrophil collagenase), MMP-3 (stromelysin-1), neutrophil elastase, and bacterial collagenase. Sites and order of cleavage of the rat MBL mutants for MMP-2 and MMP-9 were: Gly(45)-Lys(46) --> Gly(51)-Ser(52) --> Gly(63)-Gln(64) --> Asn(80)-Met(81) which differed from that of MMP-14, Gly(39)-Leu(40) --> Asn(80)-Met(81), revealing that the MMPs were not functionally interchangeable. These sites were homologous to those cleaved in denatured human MBL. Hence, perturbation of the collagen-like structure of MBL by natural mutations or by denaturation renders MBL susceptible to MMP cleavage. MMPs are likely to contribute to MBL deficiency in individuals with variant alleles and may also be involved in clearance of MBL and modulation of the host response in normal individuals.

  19. Matrix metalloproteinase proteolysis of the mycobacterial HSP65 protein as a potential source of immunogenic peptides in human tuberculosis.

    PubMed

    Shiryaev, Sergey A; Cieplak, Piotr; Aleshin, Alexander E; Sun, Qing; Zhu, Wenhong; Motamedchaboki, Khatereh; Sloutsky, Alexander; Strongin, Alex Y

    2011-09-01

    Mycobacterium tuberculosis is the causative agent of human tuberculosis (TB). Mycobacterial secretory protein ESAT-6 induces matrix metalloproteinase (MMP)-9 in epithelial cells neighboring infected macrophages. MMP-9 then enhances recruitment of uninfected macrophages, which contribute to nascent granuloma maturation and bacterial growth. Disruption of MMP-9 function attenuates granuloma formation and bacterial growth. The abundant mycobacterial 65 kDa heat shock protein (HSP65) chaperone is the major target for the immune response and a critical component in M. tuberculosis adhesion to macrophages. We hypothesized that HSP65 is susceptible to MMP-9 proteolysis and that the resulting HSP65 immunogenic peptides affect host adaptive immunity. To identify MMPs that cleave HSP65, we used MMP-2 and MMP-9 gelatinases, the simple hemopexin domain MMP-8, membrane-associated MMP-14, MMP-15, MMP-16 and MMP-24, and glycosylphosphatidylinositol-linked MMP-17 and MMP-25. We determined both the relative cleavage efficiency of MMPs against the HSP65 substrate and the peptide sequence of the cleavage sites. Cleavage of the unstructured PAGHG474L C-terminal region initiates the degradation of HSP65 by MMPs. This initial cleavage destroys the substrate-binding capacity of the HSP65 chaperone. Multiple additional cleavages of the unfolded HSP65 then follow. MMP-2, MMP-8, MMP-14, MMP-15 and MMP-16, in addition to MMP-9, generate the known highly immunogenic N-terminal peptide of HSP65. Based on our biochemical data, we now suspect that MMP proteolysis of HSP65 in vivo, including MMP-9 proteolysis, also results in the abundant generation of the N-terminal immunogenic peptide and that this peptide, in addition to intact HSP65, contributes to the complex immunomodulatory interplay in the course of TB infection.

  20. Regenerative potential of decellularized porcine nucleus pulposus hydrogel scaffolds: stem cell differentiation, matrix remodeling, and biocompatibility studies.

    PubMed

    Mercuri, Jeremy J; Patnaik, Sourav; Dion, Grace; Gill, Sanjitpal S; Liao, Jun; Simionescu, Dan T

    2013-04-01

    Nucleus pulposus (NP) tissue regeneration has been proposed as an early stage interventional therapy to combat intervertebral disc degeneration. We have previously reported on the development and characterization of a novel biomimetic acellular porcine NP (APNP) hydrogel. Herein, we aimed to evaluate this material for use as a suitable scaffold for NP tissue regeneration. Human-adipose-derived stem cells (hADSCs) were cultured for 14 days on APNP hydrogels in chemically defined differentiation media and were analyzed for an NP-cell-like mRNA expression profile, evidence of hydrogel remodeling including hydrogel contraction measurements, extracellular matrix production, and compressive dynamic mechanical properties. The innate capacity of the hydrogel itself to induce stem cell differentiation was also examined via culture in media lacking soluble differentiation factors. Additionally, the in vivo biocompatibility of non-crosslinked and ethyldimethylaminopropyl carbodiimide/N-hydroxysuccinimide and pentagalloyl glucose crosslinked hydrogels was evaluated in a rat subdermal model. Results indicated that hADSCs expressed putative NP-cell-positive gene transcript markers when cultured on APNP hydrogels. Additionally, glycosaminoglycan and collagen content of hADSC-seeded hydrogels was significantly greater than nonseeded controls and cell-seeded hydrogels exhibited evidence of contraction and tissue inhibitors of metalloproteinase-1 production. The dynamic mechanical properties of the hADSC-seeded hydrogels increased with time in culture in comparison to noncell-seeded controls and approached values reported for native NP tissue. Immunohistochemical analysis of explants illustrated the presence of mononuclear cells, including macrophages and fibroblasts, as well as blood vessel infiltration and collagen deposition within the implant interstices after 4 weeks of implantation. Taken together, these results suggest that APNP hydrogels, in concert with autologous ADSCs

  1. The spatial distribution, accumulation and potential source of seldom monitored trace elements in sediments of Three Gorges Reservoir, China

    PubMed Central

    Han, Lanfang; Gao, Bo; Zhou, Huaidong; Xu, Dongyu; Wei, Xin; Gao, Li

    2015-01-01

    The alteration of hydrologic condition of Three Gorges Reservoir (TGR) after impoundment has caused numerous environmental changes. This study investigated the distribution, accumulation and potential sources of the seldom monitored trace elements (SMTEs) in sediments from three tributaries (ZY, MX and CT) and one mainstream (CJ) in TGR during different seasons. The average contents of most SMTEs excluding Sb in the winter were similar to that in the summer. For Sb, its average concentrations in the summer and winter were roughly six and three times higher than its background value, respectively. Contamination factor (CF) and geoaccumulation index (Igeo) demonstrated that most of the sediments were obviously contaminated by Sb. The enrichment factors (EF) of Ga and Sb were higher than 2.0, revealing the possible anthropogenic inputs; However, the EFs of other SMTEs were lower than 1.5, indicating the natural inputs. Correlation and principal component analysis suggested the most SMTEs were positively correlated with major elements (Cr, Mn, Cu, Zn, As, Cd and Pb) and clay contents, which implies that SMTEs had the same sources with these major metals, and the fine particles might be a major carrier for transporting SMTEs from the rivers to the TGR. PMID:26538153

  2. The spatial distribution, accumulation and potential source of seldom monitored trace elements in sediments of Three Gorges Reservoir, China.

    PubMed

    Han, Lanfang; Gao, Bo; Zhou, Huaidong; Xu, Dongyu; Wei, Xin; Gao, Li

    2015-11-05

    The alteration of hydrologic condition of Three Gorges Reservoir (TGR) after impoundment has caused numerous environmental changes. This study investigated the distribution, accumulation and potential sources of the seldom monitored trace elements (SMTEs) in sediments from three tributaries (ZY, MX and CT) and one mainstream (CJ) in TGR during different seasons. The average contents of most SMTEs excluding Sb in the winter were similar to that in the summer. For Sb, its average concentrations in the summer and winter were roughly six and three times higher than its background value, respectively. Contamination factor (CF) and geoaccumulation index (Igeo) demonstrated that most of the sediments were obviously contaminated by Sb. The enrichment factors (EF) of Ga and Sb were higher than 2.0, revealing the possible anthropogenic inputs; However, the EFs of other SMTEs were lower than 1.5, indicating the natural inputs. Correlation and principal component analysis suggested the most SMTEs were positively correlated with major elements (Cr, Mn, Cu, Zn, As, Cd and Pb) and clay contents, which implies that SMTEs had the same sources with these major metals, and the fine particles might be a major carrier for transporting SMTEs from the rivers to the TGR.

  3. RNA aptamers as genetic control devices: the potential of riboswitches as synthetic elements for regulating gene expression.

    PubMed

    Berens, Christian; Groher, Florian; Suess, Beatrix

    2015-02-01

    RNA utilizes many different mechanisms to control gene expression. Among the regulatory elements that respond to external stimuli, riboswitches are a prominent and elegant example. They consist solely of RNA and couple binding of a small molecule ligand to the so-called "aptamer domain" with a conformational change in the downstream "expression platform" which then determines system output. The modular organization of riboswitches and the relative ease with which ligand-binding RNA aptamers can be selected in vitro against almost any molecule have led to the rapid and widespread adoption of engineered riboswitches as artificial genetic control devices in biotechnology and synthetic biology over the past decade. This review highlights proof-of-principle applications to demonstrate the versatility and robustness of engineered riboswitches in regulating gene expression in pro- and eukaryotes. It then focuses on strategies and parameters to identify aptamers that can be integrated into synthetic riboswitches that are functional in vivo, before finishing with a reflection on how to improve the regulatory properties of engineered riboswitches, so that we can not only further expand riboswitch applicability, but also finally fully exploit their potential as control elements in regulating gene expression. PMID:25676052

  4. The spatial distribution, accumulation and potential source of seldom monitored trace elements in sediments of Three Gorges Reservoir, China.

    PubMed

    Han, Lanfang; Gao, Bo; Zhou, Huaidong; Xu, Dongyu; Wei, Xin; Gao, Li

    2015-01-01

    The alteration of hydrologic condition of Three Gorges Reservoir (TGR) after impoundment has caused numerous environmental changes. This study investigated the distribution, accumulation and potential sources of the seldom monitored trace elements (SMTEs) in sediments from three tributaries (ZY, MX and CT) and one mainstream (CJ) in TGR during different seasons. The average contents of most SMTEs excluding Sb in the winter were similar to that in the summer. For Sb, its average concentrations in the summer and winter were roughly six and three times higher than its background value, respectively. Contamination factor (CF) and geoaccumulation index (Igeo) demonstrated that most of the sediments were obviously contaminated by Sb. The enrichment factors (EF) of Ga and Sb were higher than 2.0, revealing the possible anthropogenic inputs; However, the EFs of other SMTEs were lower than 1.5, indicating the natural inputs. Correlation and principal component analysis suggested the most SMTEs were positively correlated with major elements (Cr, Mn, Cu, Zn, As, Cd and Pb) and clay contents, which implies that SMTEs had the same sources with these major metals, and the fine particles might be a major carrier for transporting SMTEs from the rivers to the TGR. PMID:26538153

  5. Occurrence, distribution, and ecological risk assessment of potentially toxic elements in surface sediments of Lake Awassa and Lake Ziway, Ethiopia.

    PubMed

    Mekonnen, Kebede N; Ambushe, Abayneh A; Chandravanshi, Bhagwan S; Redi-Abshiro, Mesfin; McCrindle, Robert I

    2015-01-01

    Microwave-assisted acid digestion and modified aqua regia (HNO3:HCl:HF:H3BO3) leaching techniques were used for the determination of 15 potentially toxic elements (V, Cr, Fe, Mn, Co, Ni, Cu, Zn, As, Se, Ag, Cd, Sn, Hg and Pb) in sediment samples from Lake Awassa and Lake Ziway, Ethiopia. The digests were subsequently analyzed by inductively coupled plasma-mass spectrometry (ICP-MS) and inductively coupled plasma-optical emission spectrometry (ICP-OES). Mercury was directly determined in the solid samples using an elemental mercury analyzer. The precision and accuracy of the digestion procedures were verified using certified reference materials. The experimental results were in good agreement with the certified values (P < 0.05) and the recoveries were quantitative (>90%). The average relative standard deviations were below 10%. There is significant correlation between the two lakes at the 0.01 level (2-tailed). Using the sediment quality guidelines, both lakes are heavily polluted with Zn and some of the sites are heavily polluted with Cu, Ni and Pb. Based on effect range low (ERL) - effect range medium (ERM), in both lakes for Ag were greater than the ERM, indicating that the areas could be toxic to aquatic organisms, while for Cr, Cu, As and Hg the values were less than ERL. PMID:25438135

  6. Difficulties in using soil-based methods to assess plant availability of potentially toxic elements in biochars and their feedstocks.

    PubMed

    Farrell, Mark; Rangott, Glen; Krull, Evelyn

    2013-04-15

    The use of biochars in agriculture to improve soil function and carbon sequestration is expected to increase into the future. We aimed to identify the most suitable chemical extractants for the risk assessment of potentially toxic element (PTE) availability in biochars produced from a range of feedstocks, and to investigate the changes in PTE extractability that occur as a result of feedstock pyrolysis using five common extraction methods. We evaluated these methods with regard to their ability to predict PTE phytoavailability in four different biochars against metal uptake by wheat. No single extractant significantly correlated well with ≥ 4 PTEs from the 10 examined, highlighting that the availability and binding mechanism of individual PTEs differed by biochar type. Commonly used PTE extraction methods need to be reviewed for use with biochars, and that some biochars may be able to stabilise PTEs, reducing risks of contamination upon land application.

  7. Bioavailability and soil-to-plant transfer factors as indicators of potentially toxic element contamination in agricultural soils.

    PubMed

    Adamo, Paola; Iavazzo, Pietro; Albanese, Stefano; Agrelli, Diana; De Vivo, Benedetto; Lima, Annamaria

    2014-12-01

    Soil pollution in agricultural lands poses a serious threat to food safety, and suggests the need for consolidated methods providing advisory indications for soil management and crop production. In this work, the three-step extraction procedure developed by the EU Measurement and Testing Programme and two soil-to-plant transfer factors (relative to total and bioavailable concentration of elements in soil) were applied on polluted agricultural soils from southern Italy to obtain information on the retention mechanisms of metals in soils and on their level of translocation to edible vegetables. The study was carried out in the Sarno river plain of Campania, an area affected by severe environmental degradation potentially impacting the health of those consuming locally produced vegetables. Soil samples were collected in 36 locations along the two main rivers flowing into the plain. In 11 sites, lettuce plants were collected at the normal stage of consumption. According to Italian environmental law governing residential soils, and on the basis of soil background reference values for the study area, we found diffuse pollution by Be, Sn and Tl, of geogenic origin, Cr and Cu from anthropogenic sources such as tanneries and intensive agriculture, and more limited pollution by Pb, Zn and V. It was found that metals polluting soils as a result of human activities were mainly associated to residual, oxidizable and reducible phases, relatively immobile and only potentially bioavailable to plants. By contrast, the essential elements Zn and Cu showed a tendency to become more readily mobile and bioavailable as their total content in soil increased and were more easily transported to the edible parts of lettuce than other pollutants. According to our results, current soil pollution in the studied area does not affect the proportion of metals taken up by lettuce plants and there is a limited health risk incurred.

  8. Matrix method for acoustic levitation simulation.

    PubMed

    Andrade, Marco A B; Perez, Nicolas; Buiochi, Flavio; Adamowski, Julio C

    2011-08-01

    A matrix method is presented for simulating acoustic levitators. A typical acoustic levitator consists of an ultrasonic transducer and a reflector. The matrix method is used to determine the potential for acoustic radiation force that acts on a small sphere in the standing wave field produced by the levitator. The method is based on the Rayleigh integral and it takes into account the multiple reflections that occur between the transducer and the reflector. The potential for acoustic radiation force obtained by the matrix method is validated by comparing the matrix method results with those obtained by the finite element method when using an axisymmetric model of a single-axis acoustic levitator. After validation, the method is applied in the simulation of a noncontact manipulation system consisting of two 37.9-kHz Langevin-type transducers and a plane reflector. The manipulation system allows control of the horizontal position of a small levitated sphere from -6 mm to 6 mm, which is done by changing the phase difference between the two transducers. The horizontal position of the sphere predicted by the matrix method agrees with the horizontal positions measured experimentally with a charge-coupled device camera. The main advantage of the matrix method is that it allows simulation of non-symmetric acoustic levitators without requiring much computational effort. PMID:21859587

  9. Assessment of entrainment and deposition for a potential landslide in Lushan area, central Taiwan by 3D discrete element simulation

    NASA Astrophysics Data System (ADS)

    Lu, C.; Tang, C.; Hu, J.; Chan, Y.; Chi, C.

    2011-12-01

    The subtropical climate and annual average about four typhoons, combined with frequent earthquakes trigger the landslide hazards in mountainous area in Taiwan. The potential Lushan landslide area is located at a famous hotspring district of Nantou County in central Taiwan which slides frequently due to heavy rainfall during pouring rain or typhoon seasons. Lushan landslide demonstrates a typical deep-seated (up to 80 meters) creep deformation of a slate rock slope with high dip angles. Under the weathering effects, the slide surface is currently extending to the lower slope was formed by the coalescing of the joints on the upper eastern slope as well as the interface between the sandy slate and the slate on the upper western slope. In this study, we simulate the process of Lushan landslide by using PFC3D, which is conducted by adopting the 3D granular discrete element method. In this simulation, we assume the whole sliding block as an inhomogeneous layer of weaken slate. We extrapolate the slip plane depth according to the result of borehole, TDR and RIF profiles. The main landslide area is about 18 hectares and the volume is about 9 million cubic meters, which is filled with 30 thousand ball elements. The topography is represented by 25,620 wall elements based on the 5m digital elevation model. We set 9 monitoring balls on surface to monitor the velocity and run-out path. According to the field work, we defined the weak planes by the strike and dip of cleavage and joint. From our results, the run-out zone is about 40 hectares. The debris will cover whole Lushan hotspring district in 20 seconds and all rock mass will almost stop after 150 seconds. The predicted maximum velocity is about 40m/s. According to the velocity profile, we can see three and four times accelerations from monitored particles. The collision of particles during sliding and complex terrain explains the fluctuation of velocity profile with time. The numerical results of this study will provide

  10. A matrix effect and accuracy evaluation for the determination of elements in milk powder LIBS and laser ablation/ICP-OES spectrometry.

    PubMed

    Gilon, N; El-Haddad, J; Stankova, A; Lei, W; Ma, Q; Motto-Ros, V; Yu, J

    2011-11-01

    Laser ablation coupled to inductively coupled plasma optical emission spectrometry (LA-ICP-OES) and laser-induced breakdown spectroscopy (LIBS) were investigated for the determination of Ca, Mg, Zn and Na in milk samples. The accuracy of both methods was evaluated by comparison of the concentration found using LA-ICP-OES and LIBS with classical wet digestion associated with ICP-OES determination. The results were not fully acceptable, with biases from less than 1% to more than 60%. Matrix effects were also investigated. The sample matrix can influence the temperature, electron number density (n (e)) and other excitation characteristics in the ICP. These ICP characteristics were studied and evaluated during ablation of eight milk samples. Differences in n (e) (from 8.9 to 13.8 × 10(14) cm(-3)) and rotational temperature (ranging from 3,400 to 4,400 K) occurred with no correlation with trueness. LIBS results obtained after classical external calibration procedure gave degraded accuracy, indicating a strong matrix effect. The LIBS measurements clearly showed that the major problem in LA-ICP was related to the ablation process and that LIBS spectroscopy is an excellent diagnostic tool for LA-ICP techniques. PMID:21573840

  11. Complete determination of the photoionization dynamics of a polyatomic molecule. II. Determination of radial dipole matrix elements and phases from experimental photoelectron angular distributions from A1Au acetylene.

    PubMed

    Hockett, Paul; Reid, Katharine L

    2007-10-21

    We present a fit to photoelectron angular distributions (PADs) measured following the photoionization of rotationally selected A1Au state acetylene. In the case of the 4(1)2Sigmau- vibronic state of the ion, we are able to use this fit to make a complete determination of the radial dipole matrix elements and phases connecting the prepared level to each photoelectron partial wave. We have also investigated other Renner-Teller subbands with a view to disentangling geometrical and dynamical contributions to the resulting PADs.

  12. Gray level entropy matrix is a superior predictor than multiplex ELISA in the detection of reactive stroma and metastatic potential of high-grade prostatic adenocarcinoma.

    PubMed

    Jia, Xiaopeng; Sun, Yanan; Wang, Baozhi

    2014-12-01

    Recent reports have indicated that not only the primary glandular tissue but also the surrounding stromal tissue plays an active role in the progression of carcinoma. Such is true for cancer tissues arising in the prostate. However, the precise role of stromal tissue in benign prostatic hyperplasia (BPH) and prostate adenocarcinoma is not well described. We undertook this current investigation to examine the changes in orientation of the extracellular matrix and correlate with prostatic cancer progression. We used a novel form of image analysis called gray level entropy matrix (GLEM) texture analysis to evaluate morphometric changes in stromal tissues. We used normal prostatic tissue obtained from cadaveric specimen and compared with BPH, prostatic intraepithelium neoplastic, hormone responsive prostatic adenocarcinoma and castration-resistant prostatic adenocarcinoma tissues. GLEM showed higher entropy in disease-resistant prostatic tissues, compared with benign forms of all spectra of pathologically diagnosed prostatic tissues (P < 0.05, ANOVA, between groups). Higher entropy is reflective of the disorganized morphological organization of the stroma, possibly reflecting the reactive matrix. In contrast, ELISA revealed that although individually correlated with the progressive stages of benign and carcinomatous prostatic tissues and trend correlation between groups, intergroup comparisons failed to arrive at statistical significance of comparisons between markers of neovasculogenesis, vascular endothelial growth factor, epithelial-mesenchymal transition (beta1-integrin, E-cadherin, MMP3) and osteogenic metastasis (RANKL and osteoprotegerin). The results of our study demonstrate the potential of GLEM entropy of gray level pixel in providing quasiquantitative estimate of a reactive stroma in advance stages of prostatic adenocarcinoma and thus can be routinely used in clinical decision making.

  13. Potential and limitations of finite element modelling in assessing structural integrity of coralline algae under future global change

    NASA Astrophysics Data System (ADS)

    Melbourne, L. A.; Griffin, J.; Schmidt, D. N.; Rayfield, E. J.

    2015-02-01

    Coralline algae are important habitat formers found on all rocky shores. While the impact of future ocean acidification on the physiological performance of the species has been well studied, little research has focussed on potential changes in structural integrity in response to climate change. A previous study using 2-D Finite Element Analysis (FEA), suggested increased vulnerability to fracture (by wave action or boring) in algae grown under high CO2 conditions. To assess how realistically 2-D simplified models represent structural performance, a series of increasingly biologically accurate 3-D FE-models that represent coralline algal growth were developed. Simplified geometric 3-D models of the genus Lithothamnion were compared to models created from computed tomography (CT) scan data of the same genus. The biologically accurate model and the simplified geometric model representing individual cells had similar average stresses and stress distributions, emphasizing the importance of the cell walls in dissipating the stress throughout the structure. In contrast models without the accurate representation of the cell geometry resulted in larger stress and strain results. Our more complex 3-D model reiterated the potential of climate change to diminish the structural integrity of the organism. This suggests that under future environmental conditions the weakening of the coralline algal skeleton along with increased external pressures (wave and bioerosion) may negatively influence the ability for coralline algae to maintain a habitat able to sustain high levels of biodiversity.

  14. Potential and limitations of finite element modelling in assessing structural integrity of coralline algae under future global change

    NASA Astrophysics Data System (ADS)

    Melbourne, L. A.; Griffin, J.; Schmidt, D. N.; Rayfield, E. J.

    2015-10-01

    Coralline algae are important habitat formers found on all rocky shores. While the impact of future ocean acidification on the physiological performance of the species has been well studied, little research has focused on potential changes in structural integrity in response to climate change. A previous study using 2-D Finite Element Analysis (FEA) suggested increased vulnerability to fracture (by wave action or boring) in algae grown under high CO2 conditions. To assess how realistically 2-D simplified models represent structural performance, a series of increasingly biologically accurate 3-D FE models that represent different aspects of coralline algal growth were developed. Simplified geometric 3-D models of the genus Lithothamnion were compared to models created from computed tomography (CT) scan data of the same genus. The biologically accurate model and the simplified geometric model representing individual cells had similar average stresses and stress distributions, emphasising the importance of the cell walls in dissipating the stress throughout the structure. In contrast models without the accurate representation of the cell geometry resulted in larger stress and strain results. Our more complex 3-D model reiterated the potential of climate change to diminish the structural integrity of the organism. This suggests that under future environmental conditions the weakening of the coralline algal skeleton along with increased external pressures (wave and bioerosion) may negatively influence the ability for coralline algae to maintain a habitat able to sustain high levels of biodiversity.

  15. Sn Spheres Embedded in a SiO2 Matrix: Synthesis and Potential Application As Self-Destructing Materials.

    PubMed

    Hien, Vu Xuan; Heo, Young-Woo

    2016-08-24

    We introduce a simple process for the fabrication of SiO2 films embedded with β-Sn-rich nano/microspheres. Sn spheres with maximum and minimum sizes of 10 μm (near the SiO2 surface) and 5 nm (at the Si/SiO2 interface) were grown within a 0.7-5.7 μm-thick SiO2 layer by evaporating SnO powders onto an Si (100) substrate for 1-600 min at 600-900 °C and 0.001-5.0 Torr. A possible growth mechanism of these materials is discussed. The current-voltage characteristics of the as-fabricated samples were investigated to identify potential applications. During these tests, small flashes of light and the presence of damaged areas were observed at the oxide surfaces of the samples using an optical camera and a field emission scanning electron microscope, respectively. The electrical breakdown and shutdown of the devices observed in the current-voltage curves were attributed to the destruction of the SiO2 surface. In addition, the current-time responses show that the size of the damaged regions can be controlled by the voltage and duration of the applied stress, and are independent of the size and shape of the electrodes. The present materials thus possess great potential for applications in self-destructing devices. PMID:27463945

  16. Grassmann matrix quantum mechanics

    DOE PAGES

    Anninos, Dionysios; Denef, Frederik; Monten, Ruben

    2016-04-21

    We explore quantum mechanical theories whose fundamental degrees of freedom are rectangular matrices with Grassmann valued matrix elements. We study particular models where the low energy sector can be described in terms of a bosonic Hermitian matrix quantum mechanics. We describe the classical curved phase space that emerges in the low energy sector. The phase space lives on a compact Kähler manifold parameterized by a complex matrix, of the type discovered some time ago by Berezin. The emergence of a semiclassical bosonic matrix quantum mechanics at low energies requires that the original Grassmann matrices be in the long rectangular limit.more » In conclusion, we discuss possible holographic interpretations of such matrix models which, by construction, are endowed with a finite dimensional Hilbert space.« less

  17. A simple but accurate potential for the naphthalene-argon complex: applications to collisional energy transfer and matrix isolated IR spectroscopy.

    PubMed

    Calvo, F; Falvo, Cyril; Parneix, Pascal

    2013-01-21

    An explicit polarizable potential for the naphthalene-argon complex has been derived assuming only atomic contributions, aiming at large scale simulations of naphthalene under argon environment. The potential was parametrized from dedicated quantum chemical calculations at the CCSD(T) level, and satisfactorily reproduces available structural and energetic properties. Combining this potential with a tight-binding model for naphthalene, collisional energy transfer is studied by means of dedicated molecular dynamics simulations, nuclear quantum effects being accounted for in the path-integral framework. Except at low target temperature, nuclear quantum effects do not alter the average energies transferred by the collision or the collision duration. However, the distribution of energy transferred is much broader in the quantum case due to the significant zero-point energy and the higher density of states. Using an ab initio potential for the Ar-Ar interaction, the IR absorption spectrum of naphthalene solvated by argon clusters or an entire Ar matrix is computed via classical and centroid molecular dynamics. The classical spectra exhibit variations with growing argon environment that are absent from quantum spectra. This is interpreted by the greater fluxional character experienced by the argon atoms due to vibrational delocalization.

  18. Hybrid matrix amplifier

    DOEpatents

    Martens, J.S.; Hietala, V.M.; Plut, T.A.

    1995-01-03

    The present invention comprises a novel matrix amplifier. The matrix amplifier includes an active superconducting power divider (ASPD) having N output ports; N distributed amplifiers each operatively connected to one of the N output ports of the ASPD; and a power combiner having N input ports each operatively connected to one of the N distributed amplifiers. The distributed amplifier can included M stages of amplification by cascading superconducting active devices. The power combiner can include N active elements. The resulting (N[times]M) matrix amplifier can produce signals of high output power, large bandwidth, and low noise. 6 figures.

  19. Hybrid matrix amplifier

    DOEpatents

    Martens, Jon S.; Hietala, Vincent M.; Plut, Thomas A.

    1995-01-01

    The present invention comprises a novel matrix amplifier. The matrix amplifier includes an active superconducting power divider (ASPD) having N output ports; N distributed amplifiers each operatively connected to one of the N output ports of the ASPD; and a power combiner having N input ports each operatively connected to one of the N distributed amplifiers. The distributed amplifier can included M stages of amplification by cascading superconducting active devices. The power combiner can include N active elements. The resulting (N.times.M) matrix amplifier can produce signals of high output power, large bandwidth, and low noise.

  20. Transforming growth factor-beta 3 stimulates cartilage matrix elaboration by human marrow-derived stromal cells encapsulated in photocrosslinked carboxymethylcellulose hydrogels: potential for nucleus pulposus replacement.

    PubMed

    Gupta, Michelle S; Cooper, Elana S; Nicoll, Steven B

    2011-12-01

    Degeneration of the nucleus pulposus (NP) has been implicated as a major cause of low back pain. Tissue engineering strategies using marrow-derived stromal cells (MSCs) have been used to develop cartilaginous tissue constructs, which may serve as viable NP replacements. Supplementation with growth factors, such as transforming growth factor-beta 3 (TGF-β3), has been shown to enhance the differentiation of MSCs and promote functional tissue development of such constructs. A potential candidate material that may be useful as a scaffold for NP tissue engineering is carboxymethylcellulose (CMC), a biocompatible, cost-effective derivative of cellulose. Photocrosslinked CMC hydrogels have been shown to support NP cell viability and promote phenotypic matrix deposition capable of maintaining mechanical properties when cultured in serum-free, chemically defined medium (CDM) supplemented with TGF-β3. However, MSCs have not been characterized using this hydrogel system. In this study, human MSCs (hMSCs) were encapsulated in photocrosslinked CMC hydrogels and cultured in CDM with and without TGF-β3 to determine the effect of the growth factor on the differentiation of hMSCs toward an NP-like phenotype. Constructs were evaluated for matrix elaboration and functional properties consistent with native NP tissue. CDM supplemented with TGF-β3 resulted in significantly higher glycosaminoglycan content (762.69±220.79 ng/mg wet weight) and type II collagen (COL II) content (6.25±1.64 ng/mg wet weight) at day 21 compared with untreated samples. Immunohistochemical analyses revealed uniform, pericellular, and interterritorial staining for chondroitin sulfate proteoglycan and COL II in growth factor-supplemented constructs compared with faint, strictly pericellular staining in untreated constructs at 21 days. Consistent with matrix deposition, mechanical properties of hydrogels treated with TGF-β3 increased over time and exhibited the highest peak stress in stress-relaxation (