Testing strong interaction theories
International Nuclear Information System (INIS)
Ellis, J.
1979-01-01
The author discusses possible tests of the current theories of the strong interaction, in particular, quantum chromodynamics. High energy e + e - interactions should provide an excellent means of studying the strong force. (W.D.L.)
International Nuclear Information System (INIS)
Ebata, T.
1981-01-01
With an assumed weak multiplet structure for bosonic hadrons, which is consistent with the ΔI = 1/2 rule, it is shown that the strong interaction effective hamiltonian is compatible with the weak SU(2) x U(1) gauge transformation. Especially the rho-meson transforms as a triplet under SU(2)sub(w), and this is the origin of the rho-photon analogy. It is also shown that the existence of the non-vanishing Cabibbo angle is a necessary condition for the absence of the exotic hadrons. (orig.)
Strong-interaction nonuniversality
International Nuclear Information System (INIS)
Volkas, R.R.; Foot, R.; He, X.; Joshi, G.C.
1989-01-01
The universal QCD color theory is extended to an SU(3) 1 direct product SU(3) 2 direct product SU(3) 3 gauge theory, where quarks of the ith generation transform as triplets under SU(3)/sub i/ and singlets under the other two factors. The usual color group is then identified with the diagonal subgroup, which remains exact after symmetry breaking. The gauge bosons associated with the 16 broken generators then form two massive octets under ordinary color. The interactions between quarks and these heavy gluonlike particles are explicitly nonuniversal and thus an exploration of their physical implications allows us to shed light on the fundamental issue of strong-interaction universality. Nonuniversality and weak flavor mixing are shown to generate heavy-gluon-induced flavor-changing neutral currents. The phenomenology of these processes is studied, as they provide the major experimental constraint on the extended theory. Three symmetry-breaking scenarios are presented. The first has color breaking occurring at the weak scale, while the second and third divorce the two scales. The third model has the interesting feature of radiatively induced off-diagonal Kobayashi-Maskawa matrix elements
Kinetic theory for strongly coupled Coulomb systems
Dufty, James; Wrighton, Jeffrey
2018-01-01
The calculation of dynamical properties for matter under extreme conditions is a challenging task. The popular Kubo-Greenwood model exploits elements from equilibrium density-functional theory (DFT) that allow a detailed treatment of electron correlations, but its origin is largely phenomenological; traditional kinetic theories have a more secure foundation but are limited to weak ion-electron interactions. The objective here is to show how a combination of the two evolves naturally from the short-time limit for the generator of the effective single-electron dynamics governing time correlation functions without such limitations. This provides a theoretical context for the current DFT-related approach, the Kubo-Greenwood model, while showing the nature of its corrections. The method is to calculate the short-time dynamics in the single-electron subspace for a given configuration of the ions. This differs from the usual kinetic theory approach in which an average over the ions is performed as well. In this way the effective ion-electron interaction includes strong Coulomb coupling and is shown to be determined from DFT. The correlation functions have the form of the random-phase approximation for an inhomogeneous system but with renormalized ion-electron and electron-electron potentials. The dynamic structure function, density response function, and electrical conductivity are calculated as examples. The static local field corrections in the dielectric function are identified in this way. The current analysis is limited to semiclassical electrons (quantum statistical potentials), so important quantum conditions are excluded. However, a quantization of the kinetic theory is identified for broader application while awaiting its detailed derivation.
Strong interaction phenomenology
International Nuclear Information System (INIS)
Giffon, M.
1989-01-01
A brief review of high energy hadronic data (Part I)is followed by an introduction to the standard (Weinberg Salam Glashow) model of electroweak interactions and its extension to the hadrons (Part II). Rudiments of QCD and of the parton model area given in Part III together with a quick review of the spectroscopy of heavy flavours whereas Part IV is devoted to the introduction to deep inelastic scattering and to the so-called EMC effects. (author)
Energy Technology Data Exchange (ETDEWEB)
Pelaez, Jose R
1998-12-14
We present a brief pedagogical introduction to the Effective Electroweak Chiral Lagrangians, which provide a model independent description of the WW interactions in the strong regime. When it is complemented with some unitarization or a dispersive approach, this formalism allows the study of the general strong scenario expected at the LHC, including resonances.
Strong interaction at finite temperature
Indian Academy of Sciences (India)
Abstract. We review two methods discussed in the literature to determine the effective parameters of strongly interacting particles as they move through a heat bath. The first one is the general method of chiral perturbation theory, which may be readily applied to this problem. The other is the method of thermal QCD sum rules ...
Strongly Interacting Light Dark Matter
Directory of Open Access Journals (Sweden)
Sebastian Bruggisser, Francesco Riva, Alfredo Urbano
2017-09-01
Full Text Available In the presence of approximate global symmetries that forbid relevant interactions, strongly coupled light Dark Matter (DM can appear weakly coupled at small energy and generate a sizable relic abundance. Fundamental principles like unitarity restrict these symmetries to a small class, where the leading interactions are captured by effective operators up to dimension-8. Chiral symmetry, spontaneously broken global symmetries and non-linearly realized supersymmetry are examples of this. Their DM candidates (composite fermions, pseudo Nambu-Goldstone Bosons and Goldstini are interesting targets for LHC missing-energy searches.
Strongly interacting light dark matter
International Nuclear Information System (INIS)
Bruggisser, Sebastian; Riva, Francesco; Urbano, Alfredo
2016-07-01
In the presence of approximate global symmetries that forbid relevant interactions, strongly coupled light Dark Matter (DM) can appear weakly coupled at small-energy and generate a sizable relic abundance. Fundamental principles like unitarity restrict these symmetries to a small class, where the leading interactions are captured by effective operators up to dimension-8. Chiral symmetry, spontaneously broken global symmetries and non-linearly realized supersymmetry are examples of this. Their DM candidates (composite fermions, pseudo-Nambu-Goldstone Bosons and Goldstini) are interesting targets for LHC missing-energy searches.
Scalar strong interaction hadron theory
Hoh, Fang Chao
2015-01-01
The scalar strong interaction hadron theory, SSI, is a first principles' and nonlocal theory at quantum mechanical level that provides an alternative to low energy QCD and Higgs related part of the standard model. The quark-quark interaction is scalar rather than color-vectorial. A set of equations of motion for mesons and another set for baryons have been constructed. This book provides an account of the present state of a theory supposedly still at its early stage of development. This work will facilitate researchers interested in entering into this field and serve as a basis for possible future development of this theory.
Strongly interacting photons and atoms
International Nuclear Information System (INIS)
Alge, W.
1999-05-01
This thesis contains the main results of the research topics I have pursued during the my PhD studies at the University of Innsbruck and partly in collaboration with the Institut d' Optique in Orsay, France. It is divided into three parts. The first and largest part discusses the possibility of using strong standing waves as a tool to cool and trap neutral atoms in optical cavities. This is very important in the field of nonlinear optics where several successful experiments with cold atoms in cavities have been performed recently. A discussion of the optical parametric oscillator in a regime where the nonlinearity dominates the evolution is the topic of the second part. We investigated mainly the statistical properties of the cavity output of the three interactive cavity modes. Very recently a system has been proposed which promises fantastic properties. It should exhibit a giant Kerr nonlinearity with negligible absorption thus leading to a photonic turnstile device based on cold atoms in cavity. We have shown that this model suffers from overly simplistic assumptions and developed several more comprehensive approaches to study the behavior of this system. Apart from the division into three parts of different contents the thesis is divided into publications, supplements and invisible stuff. The intention of the supplements is to reach researchers which work in related areas and provide them with more detailed information about the concepts and the numerical tools we used. It is written especially for diploma and PhD students to give them a chance to use the third part of our work which is actually the largest one. They consist of a large number of computer programs we wrote to investigate the behavior of the systems in parameter regions where no hope exists to solve the equations analytically. (author)
Remnants of strong tidal interactions
International Nuclear Information System (INIS)
Mcglynn, T.A.
1990-01-01
This paper examines the properties of stellar systems that have recently undergone a strong tidal shock, i.e., a shock which removes a significant fraction of the particles in the system, and where the shocked system has a much smaller mass than the producer of the tidal field. N-body calculations of King models shocked in a variety of ways are performed, and the consequences of the shocks are investigated. The results confirm the prediction of Jaffe for shocked systems. Several models are also run where the tidal forces on the system are constant, simulating a circular orbit around a primary, and the development of tidal radii under these static conditions appears to be a mild process which does not dramatically affect material that is not stripped. The tidal radii are about twice as large as classical formulas would predict. Remnant density profiles are compared with a sample of elliptical galaxies, and the implications of the results for the development of stellar populations and galaxies are considered. 38 refs
Algebra of strong and electroweak interactions
International Nuclear Information System (INIS)
Bolokhov, S.V.; Vladimirov, Yu.S.
2004-01-01
The algebraic approach to describing the electroweak and strong interactions is considered within the frames of the binary geometrophysics, based on the principles of the Fokker-Feynman direct interparticle interaction theories of the Kaluza-Klein multidimensional geometrical models and the physical structures theory. It is shown that in this approach the electroweak and strong elementary particles interaction through the intermediate vector bosons, are characterized by the subtypes of the algebraic classification of the complex 3 x 3-matrices [ru
The Charm and Beauty of Strong Interactions
El-Bennich, Bruno
2018-01-01
We briefly review common features and overlapping issues in hadron and flavor physics focussing on continuum QCD approaches to heavy bound states, their mass spectrum and weak decay constants in different strong interaction models.
Including virtual photons in strong interactions
International Nuclear Information System (INIS)
Rusetsky, A.
2003-01-01
In the perturbative field-theoretical models we investigate the inclusion of the electromagnetic interactions into the purely strong theory that describes hadronic processes. In particular, we study the convention for splitting electromagnetic and strong interactions and the ambiguity of such a splitting. The issue of the interpretation of the parameters of the low-energy effective field theory in the presence of electromagnetic interactions is addressed, as well as the scale and gauge dependence of the effective theory couplings. We hope, that the results of these studies are relevant for the electromagnetic sector of ChPT. (orig.)
A theory of the strong interactions
International Nuclear Information System (INIS)
Gross, D.J.
1979-01-01
The most promising candidate for a fundamental microscopic theory of the strong interactions is a gauge theory of colored quarks-Quantum Chromodynamics (QCD). There are many excellent reasons for believing in this theory. It embodies the broken symmetries, SU(3) and chiral SU(3)xSU(3), of the strong interactions and reflects the success of (albeit crude) quark models in explaining the spectrum of the observed hadrons. The hidden quantum number of color, necessary to account for the quantum numbers of the low lying hadrons, plays a fundamental role in this theory as the SU(3) color gauge vector 'gluons' are the mediators of the strong interactions. The absence of physical quark states can be 'explained' by the hypothesis of color confinement i.e. that hadrons are permanently bound in color singlet bound states. Finally this theory is unique in being asymptotically free, thus accounting for the almost free field theory behvior of quarks observed at short distances. (Auth.)
Electroweak and Strong Interactions Phenomenology, Concepts, Models
Scheck, Florian
2012-01-01
Electroweak and Strong Interaction: Phenomenology, Concepts, Models, begins with relativistic quantum mechanics and some quantum field theory which lay the foundation for the rest of the text. The phenomenology and the physics of the fundamental interactions are emphasized through a detailed discussion of the empirical fundamentals of unified theories of strong, electromagnetic, and weak interactions. The principles of local gauge theories are described both in a heuristic and a geometric framework. The minimal standard model of the fundamental interactions is developed in detail and characteristic applications are worked out. Possible signals of physics beyond that model, notably in the physics of neutrinos are also discussed. Among the applications scattering on nucleons and on nuclei provide salient examples. Numerous exercises with solutions make the text suitable for advanced courses or individual study. This completely updated revised new edition contains an enlarged chapter on quantum chromodynamics an...
Vector mesons in strongly interacting matter
Indian Academy of Sciences (India)
probes like photons, pions or protons or the heated and compressed hadronic matter generated in a heavy-ion collision. Leaving any nuclear medium without strong final-state interactions, dileptons are the optimum decay channel as they avoid any final-state distortion of the 4- momenta of the decay products entering eq.
Vector mesons in strongly interacting matter
Indian Academy of Sciences (India)
Properties of hadrons in strongly interacting matter provide a link between quantum chromodynamics in the ... Top: Spectral function of the ρ-meson at normal nuclear matter density as a function of mass and ... directly but folded with the branching ratio ΓV →p1+p2 /Γtot into the specific final channel one is investigating.
Strong interaction studies with kaonic atoms
Directory of Open Access Journals (Sweden)
Marton J.
2016-01-01
Full Text Available The strong interaction of antikaons (K− with nucleons and nuclei in the low-energy regime represents an active research field connected intrinsically with few-body physics. There are important open questions like the question of antikaon nuclear bound states - the prototype system being K−pp. A unique and rather direct experimental access to the antikaon-nucleon scattering lengths is provided by precision X-ray spectroscopy of transitions in low-lying states of light kaonic atoms like kaonic hydrogen isotopes. In the SIDDHARTA experiment at the electron-positron collider DAΦNE of LNF-INFN we measured the most precise values of the strong interaction observables, i.e. the strong interaction on the 1s ground state of the electromagnetically bound K−p atom leading to a hadronic shift ϵ1s and a hadronic broadening Γ1s of the 1s state. The SIDDHARTA result triggered new theoretical work which achieved major progress in the understanding of the low-energy strong interaction with strangeness. Antikaon-nucleon scattering lengths have been calculated constrained by the SIDDHARTA data on kaonic hydrogen. For the extraction of the isospin-dependent scattering lengths a measurement of the hadronic shift and width of kaonic deuterium is necessary. Therefore, new X-ray studies with the focus on kaonic deuterium are in preparation (SIDDHARTA2. Many improvements in the experimental setup will allow to measure kaonic deuterium which is challenging due to the anticipated low X-ray yield. Especially important are the data on the X-ray yields of kaonic deuterium extracted from a exploratory experiment within SIDDHARTA.
Kinetic Profile of Neuropeptide-Receptor Interactions.
Nederpelt, Indira; Bunnik, Julia; IJzerman, Adriaan P; Heitman, Laura H
2016-12-01
Currently, drug discovery focusses only on quantifying pharmacological parameters, sometimes including binding kinetics, of drug candidates. For a complete understanding of a drug's desired binding kinetics, the kinetics of both the target and its endogenous ligands should be considered. This is because the release and binding kinetics of endogenous ligands in addition to receptor internalization rates are significant contributors to drug-target interactions. Here, we discuss the kinetic profile of three neuropeptides and their receptors; gonadotropin-releasing hormone receptor (GnRHR), neuropeptide Y receptors, and corticotropin-releasing factor receptor 1 (CRF 1 R). These three examples provide new insights into the importance of kinetic profiles which could improve the understanding of desired drug-target binding kinetics and advance drug discovery for various neurological and psychiatric illnesses. Copyright Â© 2016 Elsevier Ltd. All rights reserved.
Directory of Open Access Journals (Sweden)
Takashi Yanagisawa
2015-01-01
Full Text Available We investigate the ground state of two-dimensional Hubbard model on the basis of the variational Monte Carlo method. We use wave functions that include kinetic correlation and doublon-holon correlation beyond the Gutzwiller ansatz. It is still not clear whether the Hubbard model accounts for high-temperature superconductivity. The antiferromagnetic correlation plays a key role in the study of pairing mechanism because the superconductive phase exists usually close to the antiferromagnetic phase. We investigate the stability of the antiferromagnetic state when holes are doped as a function of the Coulomb repulsion U. We show that the antiferromagnetic correlation is suppressed as U is increased exceeding the bandwidth. High-temperature superconductivity is possible in this region with enhanced antiferromagnetic spin fluctuation and pairing interaction.
Fundamental Structure of Matter and Strong Interaction
Energy Technology Data Exchange (ETDEWEB)
Jian-Ping Chen
2011-11-01
More than 99% of the visible matter in the universe are the protons and neutrons. Their internal structure is mostly governed by the strong interaction. Understanding their internal structure in terms of fundamental degrees-of-freedom is one of the most important subjects in modern physics. Worldwide efforts in the last few decades have lead to numerous surprises and discoveries, but major challenges still remain. An overview of the progress will be presented with a focus on the recent studies of the proton and neutron's electromagnetic and spin structure. Future perspectives will be discussed.
Strong Interaction Studies with PANDA at FAIR
International Nuclear Information System (INIS)
Schönning, Karin
2016-01-01
The Facility for Antiproton and Ion Research (FAIR) in Darmstadt, Germany, provides unique possibilities for a new generation of nuclear-, hadron- and atomic physics experiments. The future PANDA experiment at FAIR will offer a broad physics programme with emphasis on different aspects of hadron physics. Understanding the strong interaction in the perturbative regime remains one of the greatest challenges in contemporary physics and hadrons provide several important keys. In these proceedings, PANDA will be presented along with some high-lights of the planned physics programme
Strong Interactions Physics at BaBar
Energy Technology Data Exchange (ETDEWEB)
Pioppi, M.
2005-03-14
Recent results obtained by BABAR experiment and related to strong interactions physics are presented, with particular attention to the extraction of the first four hadronic-mass moments and the first three lepton-energy moments in semileptonic decays. From a simultaneous fit to the moments, the CKM element |V{sub cb}|, the inclusive B {yields} X{sub c}lv and other heavy quark parameters are derived. The second topic is the ambiguity-free measurement of cos(2{beta}) in B {yields} J/{Psi}K* decays. With approximately 88 million of B{bar B} pairs, negative solutions for cos(2{beta}) are excluded at 89%.
Strong Interaction Studies with PANDA at FAIR
Schönning, Karin
2016-10-01
The Facility for Antiproton and Ion Research (FAIR) in Darmstadt, Germany, provides unique possibilities for a new generation of nuclear-, hadron- and atomic physics experiments. The future PANDA experiment at FAIR will offer a broad physics programme with emphasis on different aspects of hadron physics. Understanding the strong interaction in the perturbative regime remains one of the greatest challenges in contemporary physics and hadrons provide several important keys. In these proceedings, PANDA will be presented along with some high-lights of the planned physics programme.
Strong Interactive Massive Particles from a Strong Coupled Theory
DEFF Research Database (Denmark)
Yu. Khlopov, Maxim; Kouvaris, Christoforos
2008-01-01
(-2). These excessive techniparticles are all captured by $^4He$, creating \\emph{techni-O-helium} $tOHe$ ``atoms'', as soon as $^4He$ is formed in Big Bang Nucleosynthesis. The interaction of techni-O-helium with nuclei opens new paths to the creation of heavy nuclei in Big Bang Nucleosynthesis. Due...
Finite temperature system of strongly interacting baryons
Energy Technology Data Exchange (ETDEWEB)
Bowers, R.L.; Gleeson, A.M.; Pedigo, R.D.; Wheeler, J.W.
1976-07-01
A fully relativistic finite temperature many body theory is constructed and used to examine the bulk properties of a system of strongly interacting baryons. The strong interactions are described by a two parameter phenomenological model fit to a simple description of nuclear matter at T = 0. The zero temperature equation of state for such a system which has already been discussed in the literature was developed to give a realistic description of nuclear matter. The model presented here is the exact finite temperature extension of that model. The effect of the inclusion of baryon pairs for T greater than or equal to 2mc/sup 2//k is discussed in detail. The phase transition identified with nuclear matter vanishes for system temperatures in excess of T/sub C/ = 1.034 x 10/sup 11/ /sup 0/K. All values of epsilon (P,T) correspond to systems that are causal in the sense that the locally determined speed of sound never exceeds the speed of light.
Finite temperature system of strongly interacting baryons
International Nuclear Information System (INIS)
Bowers, R.L.; Gleeson, A.M.; Pedigo, R.D.; Wheeler, J.W.
1976-07-01
A fully relativistic finite temperature many body theory is constructed and used to examine the bulk properties of a system of strongly interacting baryons. The strong interactions are described by a two parameter phenomenological model fit to a simple description of nuclear matter at T = 0. The zero temperature equation of state for such a system which has already been discussed in the literature was developed to give a realistic description of nuclear matter. The model presented here is the exact finite temperature extension of that model. The effect of the inclusion of baryon pairs for T greater than or equal to 2mc 2 /k is discussed in detail. The phase transition identified with nuclear matter vanishes for system temperatures in excess of T/sub C/ = 1.034 x 10 11 0 K. All values of epsilon (P,T) correspond to systems that are causal in the sense that the locally determined speed of sound never exceeds the speed of light
Convex Modeling of Interactions with Strong Heredity.
Haris, Asad; Witten, Daniela; Simon, Noah
2016-01-01
We consider the task of fitting a regression model involving interactions among a potentially large set of covariates, in which we wish to enforce strong heredity. We propose FAMILY, a very general framework for this task. Our proposal is a generalization of several existing methods, such as VANISH [Radchenko and James, 2010], hierNet [Bien et al., 2013], the all-pairs lasso, and the lasso using only main effects. It can be formulated as the solution to a convex optimization problem, which we solve using an efficient alternating directions method of multipliers (ADMM) algorithm. This algorithm has guaranteed convergence to the global optimum, can be easily specialized to any convex penalty function of interest, and allows for a straightforward extension to the setting of generalized linear models. We derive an unbiased estimator of the degrees of freedom of FAMILY, and explore its performance in a simulation study and on an HIV sequence data set.
Strongly Interacting Matter at High Energy Density
International Nuclear Information System (INIS)
McLerran, L.
2008-01-01
This lecture concerns the properties of strongly interacting matter (which is described by Quantum Chromodynamics) at very high energy density. I review the properties of matter at high temperature, discussing the deconfinement phase transition. At high baryon density and low temperature, large N c arguments are developed which suggest that high baryonic density matter is a third form of matter, Quarkyonic Matter, that is distinct from confined hadronic matter and deconfined matter. I finally discuss the Color Glass Condensate which controls the high energy limit of QCD, and forms the low x part of a hadron wavefunction. The Glasma is introduced as matter formed by the Color Glass Condensate which eventually thermalizes into a Quark Gluon Plasma
Toward a Strongly Interacting Scalar Higgs Particle
International Nuclear Information System (INIS)
Shalaby, Abouzeid M.; El-Houssieny, M.
2008-01-01
We calculate the vacuum energy of the non-Hermitian and PT symmetric (-gφ 4 ) 2+1 scalar field theory. Rather than the corresponding Hermitian theory and due to the asymptotic freedom property of the theory, the vacuum energy does not blow up for large energy scales which is a good sign to solve the hierarchy problem when using this model to break the U(1)xSU(2) symmetry in the standard model. The theory is strongly interacting and in fact, all the dimensionful parameters in the theory like mass and energy are finite even for very high energy scales. Moreover, relative to the vacuum energy for the Hermitian φ 4 theory, the vacuum energy of the non-Hermitian and PT symmetric (-gφ 4 ) 2+1 theory is tiny, which is a good sign toward the solution of the cosmological constant problem. Remarkably, these features of the non-Hermitian and PT symmetric (-gφ 4 ) 2+1 scalar field theory make it very plausible to be employed as a Higgs mechanism in the standard model instead of the problematic Hermitian Higgs mechanism
The Balescu kinetic equation with exchange interaction
International Nuclear Information System (INIS)
Belyi, V V; Kukharenko, Yu A
2009-01-01
Starting with the quantum BBGKY hierarchy for the distribution functions, we have obtained the quantum kinetic equation including the dynamical screening of the interaction potential, which exactly takes into account the exchange scattering in the plasma. The collision integral is expressed in terms of the Green function of the linearized Hartree–Fock equation. The potential energy takes into account the polarization and exchange interaction too
Nonlinear wave interactions of kinetic sound waves
Directory of Open Access Journals (Sweden)
G. Brodin
2015-08-01
Full Text Available We reconsider the nonlinear resonant interaction between three electrostatic waves in a magnetized plasma. The general coupling coefficients derived from kinetic theory are reduced here to the low-frequency limit. The main contribution to the coupling coefficient we find in this way agrees with the coefficient recently presented in Annales Geophysicae. But we also deduce another contribution which sometimes can be important, and which qualitatively agrees with that of an even more recent paper. We have thus demonstrated how results derived from fluid theory can be improved and generalized by means of kinetic theory. Possible extensions of our results are outlined.
De Sitter vacua of strongly interacting QFT
Energy Technology Data Exchange (ETDEWEB)
Buchel, Alex [Department of Applied Mathematics, University of Western Ontario,London, Ontario N6A 5B7 (Canada); Department of Physics and Astronomy, University of Western Ontario,London, Ontario N6A 5B7 (Canada); Perimeter Institute for Theoretical Physics,Waterloo, Ontario N2J 2W9 (Canada); Karapetyan, Aleksandr [Department of Applied Mathematics, University of Western Ontario,London, Ontario N6A 5B7 (Canada)
2017-03-22
We use holographic correspondence to argue that Euclidean (Bunch-Davies) vacuum is a late-time attractor of the dynamical evolution of quantum gauge theories at strong coupling. The Bunch-Davies vacuum is not an adiabatic state, if the gauge theory is non-conformal — the comoving entropy production rate is nonzero. Using the N=2{sup ∗} gauge theory holography, we explore prospects of explaining current accelerated expansion of the Universe as due to the vacuum energy of a strongly coupled QFT.
Kinetic theory for interacting Luttinger liquids
Buchhold, Michael; Diehl, Sebastian
2015-10-01
We derive a closed set of equations for the kinetics and non-equilibrium dynamics of interacting Luttinger Liquids with cubic resonant interactions. In the presence of these interactions, the Luttinger phonons become dressed but still well defined quasi-particles, characterized by a life-time much larger then the inverse energy. This enables the separation of forward time dynamics and relative time dynamics into slow and fast dynamics and justifies the so-called Wigner approximation, which can be seen as a "local-time approximation" for the relative dynamics. Applying field theoretical methods in the Keldysh framework, i.e. kinetic and Dyson-Schwinger equations, we derive a closed set of dynamic equations, describing the kinetics of normal and anomalous phonon densities, the phonon self-energy and vertex corrections for a Gaussian non-equilibrium initial state. In the limit of low phonon densities, the results from self-consistent Born approximation are recaptured, including Andreev's scaling solution for the quasi-particle life-time in a thermal state. As an application, we compute the relaxation of an excited state to its thermal equilibrium. While the intermediate time dynamics displays exponentially fast relaxation, the last stages of thermalization are governed by algebraic laws. This can be traced back to the importance of energy and momentum conservation at the longest times, which gives rise to dynamical slow modes.
Relativistic rapprochement of electromagnetic and strong interactions
International Nuclear Information System (INIS)
Strel'tsov, V.N.
1995-01-01
On the basis of the Lienard-Wiechert potential and the relativistic Yukawa potential it is shown that the corresponding interactions with velocity growth increase differently (the electromagnetic one increases faster). According to preliminary estimations they are equivalent, at distances of the 'action radius' of nuclear forces, at γ≅ 960, where γ is the Lorentz factor. 2 refs
"Strong interaction" for particle physics laboratories
2003-01-01
A new Web site pooling the communications resources of particle physics centres all over the world has just been launched. The official launching of the new particle physics website Interactions.org during the Lepton-Proton 2003 Conference at the American laboratory Fermilab was accompanied by music and a flurry of balloons. On the initiative of Fermilab, the site was created by a collaboration of communication teams from over fifteen of the world's particle physics laboratories, including KEK, SLAC, INFN, JINR and, of course, CERN, who pooled their efforts to develop the new tool. The spectacular launching of the new particle physics website Interactions.org at Fermilab on 12 August 2003. A real gateway to particle physics, the site not only contains all the latest news from the laboratories but also offers images, graphics and a video/animation link. In addition, it provides information about scientific policies, links to the universities, a very useful detailed glossary of particle physics and astrophysic...
Supersymmetry and weak, electromagnetic and strong interactions
International Nuclear Information System (INIS)
Fayet, P.
1977-01-01
A supersymmetric theory of particle interactions is discussed. It is based on the earlier model which involves gauge (or vector) superfields, and matter (or chiral) superfields; each of them describes a vector and a Majorana spinor in the first case, or a two-component Dirac spinor and a complex scalar in the second case. The new theory suggests the possible existence of spin - 1/2 gluons and heavy spin-0 quarks, besides spin - 1 gluons and spin - 1/2 quarks. To prevent scalar particles to be exchanged in processes such as μ or β decays a new class of leptons with its own quantum number is introduced; it includes charged leptons and a ''photonic neutrino''
Ion Motion in a Plasma Interacting with Strong Magnetic Fields
International Nuclear Information System (INIS)
Weingarten, A.; Grabowski, C.; Chakrabarti, N.; Maron, Y.; Fruchtmant, A.
1999-01-01
The interaction of a plasma with strong magnetic fields takes place in many laboratory experiments and astrophysical plasmas. Applying a strong magnetic field to the plasma may result in plasma displacement, magnetization, or the formation of instabilities. Important phenomena in plasma, such as the energy transport and the momentum balance, take a different form in each case. We study this interaction in a plasma that carries a short-duration (80-ns) current pulse, generating a magnetic field of up to 17 kG. The evolution of the magnetic field, plasma density, ion velocities, and electric fields are determined before and during the current pulse. The dependence of the plasma limiting current on the plasma density and composition are studied and compared to theoretical models based on the different phenomena. When the plasma collisionality is low, three typical velocities should be taken into consideration: the proton and heavier-ion Alfven velocities (v A p and v A h , respectively) and the EMHD magnetic-field penetration velocity into the plasma (v EMHD ). If both Alfven velocities are larger than v EMHD the plasma is pushed ahead of the magnetic piston and the magnetic field energy is dissipated into ion kinetic energy. If v EMHD is the largest of three velocities, the plasma become magnetized and the ions acquire a small axial momentum only. Different ion species may drift in different directions along the current lines. In this case, the magnetic field energy is probably dissipated into electron thermal energy. When vs > V EMHD > vi, as in the case of one of our experiments, ion mass separation occurs. The protons are pushed ahead of the piston while the heavier-ions become magnetized. Since the plasma electrons are unmagnetized they cannot cross the piston, and the heavy ions are probably charge-neutralized by electrons originating from the cathode that are 'born' magnetized
QCD : the theory of strong interactions Conference MT17
2001-01-01
The theory of strong interactions,Quantum Chromodynamics (QCD), predicts that the strong interaction is transmitted by the exchange of particles called gluons. Unlike the messengers of electromagnetism photons, which are electrically neutral - gluons carry a strong charge associated with the interaction they mediate. QCD predicts that the strength of the interaction between quarks and gluons becomes weaker at higher energies. LEP has measured the evolution of the strong coupling constant up to energies of 200 GeV and has confirmed this prediction.
Lateral interactions and non-equilibrium in surface kinetics
Menzel, Dietrich
2016-08-01
Work modelling reactions between surface species frequently use Langmuir kinetics, assuming that the layer is in internal equilibrium, and that the chemical potential of adsorbates corresponds to that of an ideal gas. Coverage dependences of reacting species and of site blocking are usually treated with simple power law coverage dependences (linear in the simplest case), neglecting that lateral interactions are strong in adsorbate and co-adsorbate layers which may influence kinetics considerably. My research group has in the past investigated many co-adsorbate systems and simple reactions in them. We have collected a number of examples where strong deviations from simple coverage dependences exist, in blocking, promoting, and selecting reactions. Interactions can range from those between next neighbors to larger distances, and can be quite complex. In addition, internal equilibrium in the layer as well as equilibrium distributions over product degrees of freedom can be violated. The latter effect leads to non-equipartition of energy over molecular degrees of freedom (for products) or non-equal response to those of reactants. While such behavior can usually be described by dynamic or kinetic models, the deeper reasons require detailed theoretical analysis. Here, a selection of such cases is reviewed to exemplify these points.
Intrinsic kinetics in heavy ion reactions in the strong-coupling limit
Energy Technology Data Exchange (ETDEWEB)
Isaev, P.N. (AN SSSR, Novosibirsk. Inst. Yadernoj Fiziki)
1985-02-01
A quantum statistical description is suggested for the intrinsic kinetics of nuclear systems with a strong coupling between the collective (global) dynamics and intrinsic degrees of freedom (for a double nuclear system in heavy ion reactions and mother nucleus at the descent stage of fission). The influence of the ''memory'' of the system concerning pre-history of the kinetic process on the form of the kinetic equation is studied in detail. It is shown that Markov's regime is realized at practically all evolution stages of the double nuclear system (and, certainly, in fission). The kinetic equation is written and discussed in this regime.
QCD : the theory of strong interactions Exhibition LEPFest 2000
2000-01-01
The theory of strong interactions,Quantum Chromodynamics (QCD),predicts that the strong interac- tion is transmitted by the exchange of particles called glu- ons.Unlike the messengers of electromagnetism -pho- tons,which are electrically neutral -gluons carry a strong charge associated with the interaction they mediate. QCD predicts that the strength of the interaction between quarks and gluons becomes weaker at higher energies.LEP has measured the evolution of the strong coupling constant up to energies of 200 GeV and has confirmed this prediction.
Prospects for strong interaction physics at ISABELLE. [Seven papers
Energy Technology Data Exchange (ETDEWEB)
Sidhu, D P; Trueman, T L
1977-01-01
Seven papers are presented resulting from a conference intended to stimulate thinking about how ISABELLE could be used for studying strong interactions. A separate abstract was prepared for each paper for inclusion in DOE Energy Research Abstracts (ERA). (PMA)
Strongly-Interacting Fermi Gases in Reduced Dimensions
2015-11-16
superconductivity), nuclear physics (nuclear matter), high - energy physics (effective theories of the strong interactions ), astrophysics (compact stellar objects...strongly- interacting Fermi gases confined in a standing- wave CO2 laser trap. This trap produces a periodic quasi-two-dimensional pancake geometry...predictions of the phase diagram and high temperature superfluidity. Our recent measurements reveal that pairing energy and cloud profiles can be
Quark imprisonment as the origin of strong interactions
Amati, Daniele
1974-01-01
A formal scheme is suggested in which the only dynamical ingredients are weak and electro-magnetic interactions with quarks and leptons treated on the same footing. Strong interactions are generated by the requirement that quarks do not appear physically. (7 refs).
Semicalssical quantization of interacting anyons in a strong magnetic field
International Nuclear Information System (INIS)
Levit, S.; Sivan, N.
1992-01-01
We represent a semiclassical theory of charged interacting anyons in strong magnetic fields. We apply this theory to a number of few anyons systems including two interacting anyons in the presence of an impurity and three interacting anyons. We discuss the dependence of their energy levels on the statistical parameter and find regions in which this dependence follows very different patterns. The semiclassical arguments allow to correlate these patterns with the change in the character of the classical motion of the system. (author)
Membrane-mediated interaction between strongly anisotropic protein scaffolds.
Directory of Open Access Journals (Sweden)
Yonatan Schweitzer
2015-02-01
Full Text Available Specialized proteins serve as scaffolds sculpting strongly curved membranes of intracellular organelles. Effective membrane shaping requires segregation of these proteins into domains and is, therefore, critically dependent on the protein-protein interaction. Interactions mediated by membrane elastic deformations have been extensively analyzed within approximations of large inter-protein distances, small extents of the protein-mediated membrane bending and small deviations of the protein shapes from isotropic spherical segments. At the same time, important classes of the realistic membrane-shaping proteins have strongly elongated shapes with large and highly anisotropic curvature. Here we investigated, computationally, the membrane mediated interaction between proteins or protein oligomers representing membrane scaffolds with strongly anisotropic curvature, and addressed, quantitatively, a specific case of the scaffold geometrical parameters characterizing BAR domains, which are crucial for membrane shaping in endocytosis. In addition to the previously analyzed contributions to the interaction, we considered a repulsive force stemming from the entropy of the scaffold orientation. We computed this interaction to be of the same order of magnitude as the well-known attractive force related to the entropy of membrane undulations. We demonstrated the scaffold shape anisotropy to cause a mutual aligning of the scaffolds and to generate a strong attractive interaction bringing the scaffolds close to each other to equilibrium distances much smaller than the scaffold size. We computed the energy of interaction between scaffolds of a realistic geometry to constitute tens of kBT, which guarantees a robust segregation of the scaffolds into domains.
Kinetic modelization of water-rock interaction processes
International Nuclear Information System (INIS)
Pena, J.; Gimeno, M.J.
1994-01-01
A review of basic concepts in kinetics of low temperature natural systems is given: elementary and overall reactions, steady state and reaction mechanism, sequential reactions, parallel reactions and rate-determining step, temperature dependence of rate constant and principle of detailed balancing. The current status of kinetics modeling of water/rock interaction is treated. The comparison of the mean life of the processes with the residence time of the water in the system is very useful to decide the application or not of the kinetics treatment to the water/rock interaction processes. The right application of the kinetics treatment to the water/rock interaction needs the knowledge of the magnitude of the surface through which the water/rock reaction take place and its variation with time. Two ways to treat kinetically the water/rock interaction are the Mass Transfer method and the quasi-stationary state method
Mixtures of Strongly Interacting Bosons in Optical Lattices
International Nuclear Information System (INIS)
Buonsante, P.; Penna, V.; Giampaolo, S. M.; Illuminati, F.; Vezzani, A.
2008-01-01
We investigate the properties of strongly interacting heteronuclear boson-boson mixtures loaded in realistic optical lattices, with particular emphasis on the physics of interfaces. In particular, we numerically reproduce the recent experimental observation that the addition of a small fraction of 41 K induces a significant loss of coherence in 87 Rb, providing a simple explanation. We then investigate the robustness against the inhomogeneity typical of realistic experimental realizations of the glassy quantum emulsions recently predicted to occur in strongly interacting boson-boson mixtures on ideal homogeneous lattices
Glassy states in fermionic systems with strong disorder and interactions
Schwab, David J.; Chakravarty, Sudip
2009-03-01
We study the competition between interactions and disorder in two dimensions. Whereas a noninteracting system is always Anderson localized by disorder in two dimensions, a pure system can develop a Mott gap for sufficiently strong interactions. Within a simple model, with short-ranged repulsive interactions, we show that, even in the limit of strong interaction, the Mott gap is completely washed out by disorder for an infinite system for dimensions D≤2 , leading to a glassy state. Moreover, the Mott insulator cannot maintain a broken symmetry in the presence of disorder. We then show that the probability of a nonzero gap as a function of system size falls onto a universal curve, reflecting the glassy dynamics. An analytic calculation is also presented in one dimension that provides further insight into the nature of slow dynamics.
The Use of Interactive Media in Teaching of Human Kinetics ...
African Journals Online (AJOL)
This paper x-rays how teachers of kinesiology (human kinetics) can utilize interactive media to enhance teaching of the subject. Interactive media are those media that challenges the learner to interact with the media devices as well as with each other. The Use of interactive media opens up the creativity and potentials of the ...
New results on strong-interaction effects in antiprotonic hydrogen
Gotta, D; Augsburger, M A; Borchert, G L; Castelli, C M; Chatellard, D; El-Khoury, P; Egger, J P; Gorke, H; Hauser, P R; Indelicato, P J; Kirch, K; Lenz, S; Nelms, N; Rashid, K; Schult, O W B; Siems, T; Simons, L M
1999-01-01
Lyman and Balmer transitions of antiprotonic hydrogen and deuterium have been measured at the low-energy antiproton ring LEAR at CERN in order to determine the strong interaction effects. The X-rays were detected using charge-coupled devices (CCDs) and a reflection type crystal spectrometer. The results of the measurements support the meson-exchange models describing the medium and long range part of the nucleon-antinucleon interaction. (33 refs).
New results on strong-interaction effects in antiprotonic hydrogen
International Nuclear Information System (INIS)
Anagnostopoulos, D. F.; Augsburger, M.; Borchert, G.; Castelli, C.; Chatellard, D.; El-Khoury, P.; Egger, J.-P.; Gorke, H.; Gotta, D.; Hauser, P.; Indelicato, P.; Kirch, K.; Lenz, S.; Nelms, N.; Rashid, K.; Schult, O. W. B.; Siems, Th.; Simons, L. M.
1999-01-01
Lyman and Balmer transitions of antiprotonic hydrogen and deuterium have been measured at the Low-Energy Antiproton Ring LEAR at CERN in order to determine the strong interaction effects. The X-rays were detected using Charge-Coupled Devices (CCDs) and a reflection type crystal spectrometer. The results of the measurements support the meson-exchange models describing the medium and long range part of the nucleon-antinucleon interaction
Strong light-matter interaction in graphene - Invited talk
DEFF Research Database (Denmark)
Xiao, Sanshui
of graphene with noble-metal nanostructures is currently being explored for strong light-graphene interaction. We introduce a novel hybrid graphene-metal system for studying light-matter interactions with gold-void nanostructures exhibiting resonances in the visible range[1]. The hybrid system is further......Graphene has attracted lots of attention due to its remarkable electronic and optical properties, thus providing great promise in photonics and optoelectronics. However, the performance of these devices is generally limited by the weak light-matter interaction in graphene. The combination...
Discriminative deep inelastic tests of strong interaction field theories
International Nuclear Information System (INIS)
Glueck, M.; Reya, E.
1979-02-01
It is demonstrated that recent measurements of ∫ 0 1 F 2 (x, Q 2 )dx eliminate already all strong interaction field theories except QCD. A detailed study of scaling violations of F 2 (x, Q 2 ) in QCD shows their insensitivity to the gluon content of the hadron at presently measured values of Q 2 . (orig.) [de
Strongly interacting mesoscopic systems of anyons in one dimension
DEFF Research Database (Denmark)
Zinner, N. T.
2015-01-01
Using the fractional statistical properties of so-called anyonic particles, we present exact solutions for up to six strongly interacting particles in one-dimensional confinement that interpolate the usual bosonic and fermionic limits. Specifically, we consider two-component mixtures of anyons...
Interplay of Anderson localization and strong interaction in disordered systems
Energy Technology Data Exchange (ETDEWEB)
Henseler, Peter
2010-01-15
We study the interplay of disorder localization and strong local interactions within the Anderson-Hubbard model. Taking into account local Mott-Hubbard physics and static screening of the disorder potential, the system is mapped onto an effective single-particle Anderson model, which is studied within the self-consistent theory of electron localization. For fermions, we find rich nonmonotonic behavior of the localization length {xi}, particularly in two-dimensional systems, including an interaction-induced exponential enhancement of {xi} for small and intermediate disorders and a strong reduction of {xi} due to hopping suppression by strong interactions. In three dimensions, we identify for half filling a Mott-Hubbard-assisted Anderson localized phase existing between the metallic and the Mott-Hubbard-gapped phases. For small U there is re-entrant behavior from the Anderson localized phase to the metallic phase. For bosons, the unrestricted particle occupation number per lattice site yields a monotonic enhancement of {xi} as a function of decreasing interaction, which we assume to persist until the superfluid Bose-Einstein condensate phase is entered. Besides, we study cold atomic gases expanding, by a diffusion process, in a weak random potential. We show that the density-density correlation function of the expanding gas is strongly affected by disorder and we estimate the typical size of a speckle spot, i.e., a region of enhanced or depleted density. Both a Fermi gas and a Bose-Einstein condensate (in a mean-field approach) are considered. (orig.)
Interplay of Anderson localization and strong interaction in disordered systems
International Nuclear Information System (INIS)
Henseler, Peter
2010-01-01
We study the interplay of disorder localization and strong local interactions within the Anderson-Hubbard model. Taking into account local Mott-Hubbard physics and static screening of the disorder potential, the system is mapped onto an effective single-particle Anderson model, which is studied within the self-consistent theory of electron localization. For fermions, we find rich nonmonotonic behavior of the localization length ξ, particularly in two-dimensional systems, including an interaction-induced exponential enhancement of ξ for small and intermediate disorders and a strong reduction of ξ due to hopping suppression by strong interactions. In three dimensions, we identify for half filling a Mott-Hubbard-assisted Anderson localized phase existing between the metallic and the Mott-Hubbard-gapped phases. For small U there is re-entrant behavior from the Anderson localized phase to the metallic phase. For bosons, the unrestricted particle occupation number per lattice site yields a monotonic enhancement of ξ as a function of decreasing interaction, which we assume to persist until the superfluid Bose-Einstein condensate phase is entered. Besides, we study cold atomic gases expanding, by a diffusion process, in a weak random potential. We show that the density-density correlation function of the expanding gas is strongly affected by disorder and we estimate the typical size of a speckle spot, i.e., a region of enhanced or depleted density. Both a Fermi gas and a Bose-Einstein condensate (in a mean-field approach) are considered. (orig.)
A systematic study of the strong interaction with PANDA
Messchendorp, J. G.; Hosaka, A; Khemchandani, K; Nagahiro, H; Nawa, K
2011-01-01
The theory of Quantum Chromo Dynamics (QCD) reproduces the strong interaction at distances much shorter than the size of the nucleon. At larger distance scales, the generation of hadron masses and confinement cannot yet be derived from first principles on basis of QCD. The PANDA experiment at FAIR
Measurement of strong interaction parameters in antiprotonic hydrogen and deuterium
Augsburger, M A; Borchert, G L; Chatellard, D; Egger, J P; El-Khoury, P; Gorke, H; Gotta, D; Hauser, P R; Indelicato, P J; Kirch, K; Lenz, S; Siems, T; Simons, L M
1999-01-01
In the PS207 experiment at CERN, X-rays from antiprotonic hydrogen and deuterium have been measured at low pressure. The strong interaction shift and the broadening of the K/sub alpha / transition in antiprotonic hydrogen were $9 determined. Evidence was found for the individual hyperfine components of the protonium ground state. (7 refs).
Emergence of junction dynamics in a strongly interacting Bose mixture
DEFF Research Database (Denmark)
Barfknecht, Rafael Emilio; Foerster, Angela; Zinner, Nikolaj Thomas
We study the dynamics of a one-dimensional system composed of a bosonic background and one impurity in single- and double-well trapping geometries. In the limit of strong interactions, this system can be modeled by a spin chain where the exchange coefficients are determined by the geometry of the...
Symmetry-protected collisions between strongly interacting photons.
Thompson, Jeff D; Nicholson, Travis L; Liang, Qi-Yu; Cantu, Sergio H; Venkatramani, Aditya V; Choi, Soonwon; Fedorov, Ilya A; Viscor, Daniel; Pohl, Thomas; Lukin, Mikhail D; Vuletić, Vladan
2017-02-09
Realizing robust quantum phenomena in strongly interacting systems is one of the central challenges in modern physical science. Approaches ranging from topological protection to quantum error correction are currently being explored across many different experimental platforms, including electrons in condensed-matter systems, trapped atoms and photons. Although photon-photon interactions are typically negligible in conventional optical media, strong interactions between individual photons have recently been engineered in several systems. Here, using coherent coupling between light and Rydberg excitations in an ultracold atomic gas, we demonstrate a controlled and coherent exchange collision between two photons that is accompanied by a π/2 phase shift. The effect is robust in that the value of the phase shift is determined by the interaction symmetry rather than the precise experimental parameters, and in that it occurs under conditions where photon absorption is minimal. The measured phase shift of 0.48(3)π is in excellent agreement with a theoretical model. These observations open a route to realizing robust single-photon switches and all-optical quantum logic gates, and to exploring novel quantum many-body phenomena with strongly interacting photons.
Finding strongly interacting symmetry breaking at the SSC
International Nuclear Information System (INIS)
Golden, M.
1989-02-01
Pairs of gauge bosons, W and Z, are a probe of the electroweak symmetry-breaking sector, since the numbers of two gauge boson events are much larger in strongly coupled models than weak. The doubly charged channels W + W + and W/sup /minus//W/sup/minus// are cleanest, since they do not suffer from q/bar q/ or gg fusion backgrounds. The like-charged gauge boson events are observable only if the symmetry breaking sector is strongly interacting. 19 refs., 4 figs., 2 tabs
Lifetime of dynamic heterogeneity in strong and fragile kinetically constrained spin models
International Nuclear Information System (INIS)
Leonard, Sebastien; Berthier, Ludovic
2005-01-01
Kinetically constrained spin models are schematic coarse-grained models for the glass transition which represent an efficient theoretical tool to study detailed spatio-temporal aspects of dynamic heterogeneity in supercooled liquids. Here, we study how spatially correlated dynamic domains evolve with time and compare our results to various experimental and numerical investigations. We find that strong and fragile models yield different results. In particular, the lifetime of dynamic heterogeneity remains constant and roughly equal to the alpha relaxation time in strong models, while it increases more rapidly in fragile models when the glass transition is approached
Kinetic models in spin chemistry. 1. The hyperfine interaction
DEFF Research Database (Denmark)
Mojaza, M.; Pedersen, J. B.
2012-01-01
Kinetic models for quantum systems are quite popular due to their simplicity, although they are difficult to justify. We show that the transformation from quantum to kinetic description can be done exactly for the hyperfine interaction of one nuclei with arbitrary spin; more spins are described...... with a very good approximation. The crucial points are: to represents the quantum coherent oscillations by first order rate constants, and to determine the number of kinetic channels corresponding to a given interaction. We consider a radical pair system with spin selective reactions and calculate the spin...
On the strong crack-microcrack interaction problem
Gorelik, M.; Chudnovsky, A.
1992-07-01
The problem of the crack-microcrack interaction is examined with special attention given to the iterative procedure described by Chudnovsky and Kachanov (1983), Chudnovsky et al. (1984), and Horii and Nemat-Nasser (1983), which yields erroneous results as the crack tips become closer (i.e., for strong crack interaction). To understand the source of error, the traction distributions along the microcrack line on the n-th step of iteration representing the exact and asymptotic stress fields are compared. It is shown that the asymptotic solution gives a gross overestimation of the actual traction.
Ruling out a strongly interacting standard Higgs model
International Nuclear Information System (INIS)
Riesselmann, K.; Willenbrock, S.
1997-01-01
Previous work has suggested that perturbation theory is unreliable for Higgs- and Goldstone-boson scattering, at energies above the Higgs-boson mass, for relatively small values of the Higgs quartic coupling λ(μ). By performing a summation of nonlogarithmic terms, we show that perturbation theory is in fact reliable up to relatively large coupling. This eliminates the possibility of a strongly interacting standard Higgs model at energies above the Higgs-boson mass, complementing earlier studies which excluded strong interactions at energies near the Higgs-boson mass. The summation can be formulated in terms of an appropriate scale in the running coupling, μ=√(s)/e∼√(s)/2.7, so it can be incorporated easily in renormalization-group-improved tree-level amplitudes as well as higher-order calculations. copyright 1996 The American Physical Society
A connection between the strong and weak interactions
International Nuclear Information System (INIS)
Treiman, S.B.
1989-01-01
By studying weak scattering reactions (such as pion-nucleon scattering), the author and his colleague Marvin L Goldberger became renowned in the 1950s for work on dispersion relations. As a result of their collaboration a remarkable and unexpected connection was found between strong and weak interaction quantities. Agreement with experiment was good. Work by others found the same result, but via the partially conserved axial reactor current relation between the axial current divergence and the canonical pion field. (UK)
Thermodynamics of strong-interaction matter from Lattice QCD
Ding, Heng-Tong; Karsch, Frithjof; Mukherjee, Swagato
2015-01-01
We review results from lattice QCD calculations on the thermodynamics of strong-interaction matter with emphasis on input these calculations can provide to the exploration of the phase diagram and properties of hot and dense matter created in heavy ion experiments. This review is organized as follows: 1) Introduction, 2) QCD thermodynamics on the lattice, 3) QCD phase diagram at high temperature, 4) Bulk thermodynamics, 5) Fluctuations of conserved charges, 6) Transport properties, 7) Open he...
Single molecule DNA interaction kinetics of retroviral nucleic acid chaperone proteins
Williams, Mark
2010-03-01
Retroviral nucleocapsid (NC) proteins are essential for several viral replication processes including specific genomic RNA packaging and reverse transcription. The nucleic acid chaperone activity of NC facilitates the latter process. In this study, we use single molecule biophysical methods to quantify the DNA interactions of wild type and mutant human immunodeficiency virus type 1 (HIV-1) NC and Gag and human T-cell leukemia virus type 1 (HTLV-1) NC. We find that the nucleic acid interaction properties of these proteins differ significantly, with HIV-1 NC showing rapid protein binding kinetics, significant duplex destabilization, and strong DNA aggregation, all properties that are critical components of nucleic acid chaperone activity. In contrast, HTLV-1 NC exhibits significant destabilization activity but extremely slow DNA interaction kinetics and poor aggregating capability, which explains why HTLV-1 NC is a poor nucleic acid chaperone. To understand these results, we developed a new single molecule method for quantifying protein dissociation kinetics, and applied this method to probe the DNA interactions of wild type and mutant HIV-1 and HTLV-1 NC. We find that mutations to aromatic and charged residues strongly alter the proteins' nucleic acid interaction kinetics. Finally, in contrast to HIV-1 NC, HIV-1 Gag, the nucleic acid packaging protein that contains NC as a domain, exhibits relatively slow binding kinetics, which may negatively impact its ability to act as a nucleic acid chaperone.
Viriato: a Fourier-Hermite spectral code for strongly magnetised fluid-kinetic plasma dynamics
Loureiro, Nuno; Dorland, William; Fazendeiro, Luis; Kanekar, Anjor; Mallet, Alfred; Zocco, Alessandro
2015-11-01
We report on the algorithms and numerical methods used in Viriato, a novel fluid-kinetic code that solves two distinct sets of equations: (i) the Kinetic Reduced Electron Heating Model equations [Zocco & Schekochihin, 2011] and (ii) the kinetic reduced MHD (KRMHD) equations [Schekochihin et al., 2009]. Two main applications of these equations are magnetised (Alfvnénic) plasma turbulence and magnetic reconnection. Viriato uses operator splitting to separate the dynamics parallel and perpendicular to the ambient magnetic field (assumed strong). Along the magnetic field, Viriato allows for either a second-order accurate MacCormack method or, for higher accuracy, a spectral-like scheme. Perpendicular to the field Viriato is pseudo-spectral, and the time integration is performed by means of an iterative predictor-corrector scheme. In addition, a distinctive feature of Viriato is its spectral representation of the parallel velocity-space dependence, achieved by means of a Hermite representation of the perturbed distribution function. A series of linear and nonlinear benchmarks and tests are presented, with focus on 3D decaying kinetic turbulence. Work partially supported by Fundação para a Ciência e Tecnologia via Grants UID/FIS/50010/2013 and IF/00530/2013.
The Electron-Phonon Interaction in Strongly Correlated Systems
International Nuclear Information System (INIS)
Castellani, C.; Grilli, M.
1995-01-01
We analyze the effect of strong electron-electron repulsion on the electron-phonon interaction from a Fermi-liquid point of view and show that the electron-electron interaction is responsible for vertex corrections, which generically lead to a strong suppression of the electron-phonon coupling in the v F q/ω >>1 region, while such effect is not present when v F q/ω F is the Fermi velocity and q and ω are the transferred momentum and frequency respectively. In particular the e-ph scattering is suppressed in transport properties which are dominated by low-energy-high-momentum processes. On the other hand, analyzing the stability criterion for the compressibility, which involves the effective interactions in the dynamical limit, we show that a sizable electron-phonon interaction can push the system towards a phase-separation instability. Finally a detailed analysis of these ideas is carried out using a slave-boson approach for the infinite-U three-band Hubbard model in the presence of a coupling between the local hole density and a dispersionless optical phonon. (author)
Nonperturbative Dynamics of Strong Interactions from Gauge/Gravity Duality
Energy Technology Data Exchange (ETDEWEB)
Grigoryan, Hovhannes [Louisiana State Univ., Baton Rouge, LA (United States)
2008-08-01
This thesis studies important dynamical observables of strong interactions such as form factors. It is known that Quantum Chromodynamics (QCD) is a theory which describes strong interactions. For large energies, one can apply perturbative techniques to solve some of the QCD problems. However, for low energies QCD enters into the nonperturbative regime, where di erent analytical or numerical tools have to be applied to solve problems of strong interactions. The holographic dual model of QCD is such an analytical tool that allows one to solve some nonperturbative QCD problems by translating them into a dual ve-dimensional theory de ned on some warped Anti de Sitter (AdS) background. Working within the framework of the holographic dual model of QCD, we develop a formalism to calculate form factors and wave functions of vector mesons and pions. As a result, we provide predictions of the electric radius, the magnetic and quadrupole moments which can be directly veri ed in lattice calculations or even experimentally. To nd the anomalous pion form factor, we propose an extension of the holographic model by including the Chern-Simons term required to reproduce the chiral anomaly of QCD. This allows us to nd the slope of the form factor with one real and one slightly o -shell photon which appeared to be close to the experimental ndings. We also analyze the limit of large virtualities (when the photon is far o -shell) and establish that predictions of the holographic model analytically coincide with those of perturbative QCD with asymptotic pion distribution amplitude. We also study the e ects of higher dimensional terms in the AdS/QCD model and show that these terms improve the holographic description towards a more realistic scenario. We show this by calculating corrections to the vector meson form factors and corrections to the observables such as electric radii, magnetic and quadrupole moments.
The hadronic standard model for strong and electroweak interactions
Energy Technology Data Exchange (ETDEWEB)
Raczka, R. [Soltan Inst. for Nuclear Studies, Otwock-Swierk (Poland)
1993-12-31
We propose a new model for strong and electro-weak interactions. First, we review various QCD predictions for hadron-hadron and lepton-hadron processes. We indicate that the present formulation of strong interactions in the frame work of Quantum Chromodynamics encounters serious conceptual and numerical difficulties in a reliable description of hadron-hadron and lepton-hadron interactions. Next we propose to replace the strong sector of Standard Model based on unobserved quarks and gluons by the strong sector based on the set of the observed baryons and mesons determined by the spontaneously broken SU(6) gauge field theory model. We analyse various properties of this model such as asymptotic freedom, Reggeization of gauge bosons and fundamental fermions, baryon-baryon and meson-baryon high energy scattering, generation of {Lambda}-polarization in inclusive processes and others. Finally we extend this model by electro-weak sector. We demonstrate a remarkable lepton and hadron anomaly cancellation and we analyse a series of important lepton-hadron and hadron-hadron processes such as e{sup +} + e{sup -} {yields} hadrons, e{sup +} + e{sup -} {yields} W{sup +} + W{sup -}, e{sup +} + e{sup -} {yields} p + anti-p, e + p {yields} e + p and p + anti-p {yields} p + anti-p processes. We obtained a series of interesting new predictions in this model especially for processes with polarized particles. We estimated the value of the strong coupling constant {alpha}(M{sub z}) and we predicted the top baryon mass M{sub {Lambda}{sub t}} {approx_equal} 240 GeV. Since in our model the proton, neutron, {Lambda}-particles, vector mesons like {rho}, {omega}, {phi}, J/{psi} ect. and leptons are elementary most of experimentally analysed lepton-hadron and hadron-hadron processes in LEP1, LEP2, LEAR, HERA, HERMES, LHC and SSC experiments may be relatively easily analysed in our model. (author). 252 refs, 65 figs, 1 tab.
Emergence of junction dynamics in a strongly interacting Bose mixture
DEFF Research Database (Denmark)
Barfknecht, Rafael Emilio; Foerster, Angela; Zinner, Nikolaj Thomas
We study the dynamics of a one-dimensional system composed of a bosonic background and one impurity in single- and double-well trapping geometries. In the limit of strong interactions, this system can be modeled by a spin chain where the exchange coefficients are determined by the geometry...... of the trap. We observe non-trivial dynamics when the repulsion between the impurity and the background is dominant. In this regime, the system exhibits oscillations that resemble the dynamics of a Josephson junction. Furthermore, the double-well geometry allows for an enhancement in the tunneling as compared...
Strongly modified plasmon-matter interaction with mesoscopic quantum emitters
DEFF Research Database (Denmark)
Andersen, Mads Lykke; Stobbe, Søren; Søndberg Sørensen, Anders
2011-01-01
Semiconductor quantum dots (QDs) provide useful means to couple light and matter in applications such as light-harvesting1, 2 and all-solid-state quantum information processing3, 4. This coupling can be increased by placing QDs in nanostructured optical environments such as photonic crystals...... or metallic nanostructures that enable strong confinement of light and thereby enhance the light–matter interaction. It has thus far been assumed that QDs can be described in the same way as atomic photon emitters—as point sources with wavefunctions whose spatial extent can be disregarded. Here we demonstrate...
Strongly interacting atom lasers in three-dimensional optical lattices.
Hen, Itay; Rigol, Marcos
2010-10-29
We show that the dynamical melting of a Mott insulator in a three-dimensional lattice leads to condensation at nonzero momenta, a phenomenon that can be used to generate strongly interacting atom lasers in optical lattices. For infinite on-site repulsion, the case considered here, the momenta at which bosons condense are determined analytically and found to have a simple dependence on the hopping amplitudes. The occupation of the condensates is shown to scale linearly with the total number of atoms in the initial Mott insulator. Our results are obtained by using a Gutzwiller-type mean-field approach, gauged against exact-diagonalization solutions of small systems.
Ising models of strongly coupled biological networks with multivariate interactions
Merchan, Lina; Nemenman, Ilya
2013-03-01
Biological networks consist of a large number of variables that can be coupled by complex multivariate interactions. However, several neuroscience and cell biology experiments have reported that observed statistics of network states can be approximated surprisingly well by maximum entropy models that constrain correlations only within pairs of variables. We would like to verify if this reduction in complexity results from intricacies of biological organization, or if it is a more general attribute of these networks. We generate random networks with p-spin (p > 2) interactions, with N spins and M interaction terms. The probability distribution of the network states is then calculated and approximated with a maximum entropy model based on constraining pairwise spin correlations. Depending on the M/N ratio and the strength of the interaction terms, we observe a transition where the pairwise approximation is very good to a region where it fails. This resembles the sat-unsat transition in constraint satisfaction problems. We argue that the pairwise model works when the number of highly probable states is small. We argue that many biological systems must operate in a strongly constrained regime, and hence we expect the pairwise approximation to be accurate for a wide class of problems. This research has been partially supported by the James S McDonnell Foundation grant No.220020321.
ANALYTICAL METHODS FOR KINETIC STUDIES OF BIOLOGICAL INTERACTIONS: A REVIEW
Zheng, Xiwei; Bi, Cong; Li, Zhao; Podariu, Maria; Hage, David S.
2015-01-01
The rates at which biological interactions occur can provide important information concerning the mechanism and behavior of these processes in living systems. This review discusses several analytical methods that can be used to examine the kinetics of biological interactions. These techniques include common or traditional methods such as stopped-flow analysis and surface plasmon resonance spectroscopy, as well as alternative methods based on affinity chromatography and capillary electrophoresis. The general principles and theory behind these approaches are examined, and it is shown how each technique can be utilized to provide information on the kinetics of biological interactions. Examples of applications are also given for each method. In addition, a discussion is provided on the relative advantages or potential limitations of each technique regarding its use in kinetic studies. PMID:25700721
Noise in strong laser-atom interactions: Phase telegraph noise
International Nuclear Information System (INIS)
Eberly, J.H.; Wodkiewicz, K.; Shore, B.W.
1984-01-01
We discuss strong laser-atom interactions that are subjected to jump-type (random telegraph) random-phase noise. Physically, the jumps may arise from laser fluctuations, from collisions of various kinds, or from other external forces. Our discussion is carried out in two stages. First, direct and partially heuristic calculations determine the laser spectrum and also give a third-order differential equation for the average inversion of a two-level atom on resonance. At this stage a number of general features of the interaction are able to be studied easily. The optical analog of motional narrowing, for example, is clearly predicted. Second, we show that the theory of generalized Poisson processes allows laser-atom interactions in the presence of random telegraph noise of all kinds (not only phase noise) to be treated systematically, by means of a master equation first used in the context of quantum optics by Burshtein. We use the Burshtein equation to obtain an exact expression for the two-level atom's steady-state resonance fluorescence spectrum, when the exciting laser exhibits phase telegraph noise. Some comparisons are made with results obtained from other noise models. Detailed treatments of the effects ofmly jumps, or as a model of finite laser bandwidth effects, in which the laser frequency exhibits random jumps. We show that these two types of frequency noise can be distinguished in light-scattering spectra. We also discuss examples which demonstrate both temporal and spectral motional narrowing, nonexponential correlations, and non-Lorentzian spectra. Its exact solubility in finite terms makes the frequency-telegraph noise model an attractive alternative to the white-noise Ornstein-Uhlenbeck frequency noise model which has been previously applied to laser-atom interactions
Towards a unified gauge theory of gravitational and strong interactions
International Nuclear Information System (INIS)
Hehl, F.W.; Sijacki, D.
1980-01-01
The space-time properties of leptons and hadrons is studied and it is found necessary to extend general relativity to the gauge theory based on the four-dimensional affine group. This group translates and deforms the tetrads of the locally Minkowskian space-time. Its conserved currents, momentum, and hypermomentum, act as sources in the two field equations of gravity. A Lagrangian quadratic in torsion and curvature allows for the propagation of two independent gauge fields: translational e-gravity mediated by the tetrad coefficients, and deformational GAMMA-gravity mediated by the connection coefficients. For macroscopic matter e-gravity coincides with general relativity up to the post-Newtonian approximation of fourth order. For microscopic matter GAMMA-gravity represents a strong Yang-Mills type interaction. In the linear approximation, for a static source, a confinement potential is found. (author)
Extreme states of matter in strong interaction physics an introduction
Satz, Helmut
2018-01-01
This book is a course-tested primer on the thermodynamics of strongly interacting matter – a profound and challenging area of both theoretical and experimental modern physics. Analytical and numerical studies of statistical quantum chromodynamics provide the main theoretical tool, while in experiments, high-energy nuclear collisions are the key for extensive laboratory investigations. As such, the field straddles statistical, particle and nuclear physics, both conceptually and in the methods of investigation used. The book addresses, above all, the many young scientists starting their scientific research in this field, providing them with a general, self-contained introduction that highlights the basic concepts and ideas and explains why we do what we do. Much of the book focuses on equilibrium thermodynamics: first it presents simplified phenomenological pictures, leading to critical behavior in hadronic matter and to a quark-hadron phase transition. This is followed by elements of finite temperature latti...
Quantification of protein interaction kinetics in a micro droplet
International Nuclear Information System (INIS)
Yin, L. L.; Wang, S. P.; Shan, X. N.; Tao, N. J.; Zhang, S. T.
2015-01-01
Characterization of protein interactions is essential to the discovery of disease biomarkers, the development of diagnostic assays, and the screening for therapeutic drugs. Conventional flow-through kinetic measurements need relative large amount of sample that is not feasible for precious protein samples. We report a novel method to measure protein interaction kinetics in a single droplet with sub microliter or less volume. A droplet in a humidity-controlled environmental chamber is replacing the microfluidic channels as the reactor for the protein interaction. The binding process is monitored by a surface plasmon resonance imaging (SPRi) system. Association curves are obtained from the average SPR image intensity in the center area of the droplet. The washing step required by conventional flow-through SPR method is eliminated in the droplet method. The association and dissociation rate constants and binding affinity of an antigen-antibody interaction are obtained by global fitting of association curves at different concentrations. The result obtained by this method is accurate as validated by conventional flow-through SPR system. This droplet-based method not only allows kinetic studies for proteins with limited supply but also opens the door for high-throughput protein interaction study in a droplet-based microarray format that enables measurement of many to many interactions on a single chip
Quantification of protein interaction kinetics in a micro droplet
Energy Technology Data Exchange (ETDEWEB)
Yin, L. L. [Center for Bioelectronics and Biosensors, Biodesign Institute, Arizona State University, Tempe, Arizona 85287 (United States); College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044 (China); Wang, S. P., E-mail: shaopeng.wang@asu.edu, E-mail: njtao@asu.edu; Shan, X. N.; Tao, N. J., E-mail: shaopeng.wang@asu.edu, E-mail: njtao@asu.edu [Center for Bioelectronics and Biosensors, Biodesign Institute, Arizona State University, Tempe, Arizona 85287 (United States); Zhang, S. T. [College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044 (China)
2015-11-15
Characterization of protein interactions is essential to the discovery of disease biomarkers, the development of diagnostic assays, and the screening for therapeutic drugs. Conventional flow-through kinetic measurements need relative large amount of sample that is not feasible for precious protein samples. We report a novel method to measure protein interaction kinetics in a single droplet with sub microliter or less volume. A droplet in a humidity-controlled environmental chamber is replacing the microfluidic channels as the reactor for the protein interaction. The binding process is monitored by a surface plasmon resonance imaging (SPRi) system. Association curves are obtained from the average SPR image intensity in the center area of the droplet. The washing step required by conventional flow-through SPR method is eliminated in the droplet method. The association and dissociation rate constants and binding affinity of an antigen-antibody interaction are obtained by global fitting of association curves at different concentrations. The result obtained by this method is accurate as validated by conventional flow-through SPR system. This droplet-based method not only allows kinetic studies for proteins with limited supply but also opens the door for high-throughput protein interaction study in a droplet-based microarray format that enables measurement of many to many interactions on a single chip.
Albertin, Warren; Miot-Sertier, Cécile; Bely, Marina; Marullo, Philippe; Coulon, Joana; Moine, Virginie; Colonna-Ceccaldi, Benoit; Masneuf-Pomarede, Isabelle
2014-05-16
Yeast species of Hanseniaspora and Candida genus are predominant during the early stages of winemaking, while species of Metschnikowia, Pichia, Zygoascus, Issatchenkia, Torulaspora and other genera are present at lower population levels. The impact of common oenological practices on yeast dynamics during the prefermentative stage and the early stage of alcoholic fermentation (AF) remains elusive. In this work, the effect of four prefermentative oenological practices (clarification degree, temperature, sulphite and starter yeast addition) on yeast dynamics was evaluated in a Chardonnay grape must. The growth curves of four genus or species, namely Saccharomyces spp., Hanseniaspora spp., Candida zemplinina and Torulaspora delbrueckii, were followed by quantitative PCR. The fermentation kinetics were also recorded, as well as the production of acetic acid. Variance analysis allowed determining the effect of each practice and their interaction factors, as well as their relative importance on yeast dynamics and fermentation kinetics. Our experimental design showed that the population dynamics of the four species were differently impacted by the oenological practices, with some species being more sensitive than others to the clarification degree (C. zemplinina), sulphite addition (Saccharomyces spp.), starter yeast inoculation (Hanseniaspora spp.) or prefermentation temperature (T. delbrueckii). Significant interaction effects between practices were revealed, highlighting the interest of experimental design allowing interaction analysis, as some factors may buffer the effect of other ones. Hanseniaspora genus showed atypical behaviour: growth dynamics showed a decrease during AF that we interpreted as early cellular lysis. In conclusion, this study provides new insights on the impact of common oenological practices on the dynamics of non-Saccharomyces yeast that will be useful for a better management of mixed fermentation between S. cerevisiae and non
Directory of Open Access Journals (Sweden)
Yucel Yildirim
2011-09-01
Full Text Available A generic theory of the quasiparticle superconducting gap in underdoped cuprates is derived in the strong-coupling limit, and found to describe the experimental “second gap” in absolute scale. In drastic contrast to the standard pairing gap associated with Bogoliubov quasiparticle excitations, the quasiparticle gap is shown to originate from anomalous kinetic (scattering processes, with a size unrelated to the pairing strength. Consequently, the k dependence of the gap deviates significantly from the pure d_{x^{2}-y^{2}} wave of the order parameter. Our study reveals a new paradigm for the nature of the superconducting gap, and is expected to reconcile numerous apparent contradictions among existing experiments and point toward a more coherent understanding of high-temperature superconductivity.
BGK-type models in strong reaction and kinetic chemical equilibrium regimes
International Nuclear Information System (INIS)
Monaco, R; Bianchi, M Pandolfi; Soares, A J
2005-01-01
A BGK-type procedure is applied to multi-component gases undergoing chemical reactions of bimolecular type. The relaxation process towards local Maxwellians, depending on mass and numerical densities of each species as well as common velocity and temperature, is investigated in two different cases with respect to chemical regimes. These cases are related to the strong reaction regime characterized by slow reactions, and to the kinetic chemical equilibrium regime where fast reactions take place. The consistency properties of both models are stated in detail. The trend to equilibrium is numerically tested and comparisons for the two regimes are performed within the hydrogen-air and carbon-oxygen reaction mechanism. In the spatial homogeneous case, it is also shown that the thermodynamical equilibrium of the models recovers satisfactorily the asymptotic equilibrium solutions to the reactive Euler equations
High-energy strong interactions: from `hard' to `soft'
Ryskin, M. G.; Martin, A. D.; Khoze, V. A.
2011-04-01
We discuss the qualitative features of the recent data on multiparticle production observed at the LHC. The tolerable agreement with Monte Carlos based on LO DGLAP evolution indicates that there is no qualitative difference between `hard' and `soft' interactions; and that a perturbative QCD approach may be extended into the soft domain. However, in order to describe the data, these Monte Carlos need an additional infrared cutoff k min with a value k min ˜2-3 GeV which is not small, and which increases with collider energy. Here we explain the physical origin of the large k min . Using an alternative model which matches the `soft' high-energy hadron interactions smoothly on to perturbative QCD at small x, we demonstrate that this effective cutoff k min is actually due to the strong absorption of low k t partons. The model embodies the main features of the BFKL approach, including the diffusion in transverse momenta, ln k t , and an intercept consistent with resummed next-to-leading log corrections. Moreover, the model uses a two-channel eikonal framework, and includes the contributions from the multi-Pomeron exchange diagrams, both non-enhanced and enhanced. The values of a small number of physically-motivated parameters are chosen to reproduce the available total, elastic and proton dissociation cross section (pre-LHC) data. Predictions are made for the LHC, and the relevance to ultra-high-energy cosmic rays is briefly discussed. The low x inclusive integrated gluon PDF, and the diffractive gluon PDF, are calculated in this framework, using the parameters which describe the high-energy pp and pbar{p} ` soft' data. Comparison with the PDFs obtained from the global parton analyses of deep inelastic and related hard scattering data and from diffractive deep inelastic data looks encouraging.
Lyubarsky, Yuri
2018-02-01
This paper is the first in the series of papers aiming to study interaction of the electromagnetic precursor waves generated at the front of a relativistic shock with the upstream flow. It is motivated by a simple consideration showing that the absorption of such an electromagnetic precursor could yield an efficient transformation of the kinetic energy of the upstream flow to the energy of accelerated particles. Taking into account that the precursor is a strong wave, in which electrons oscillate with relativistic velocities, the standard plasma-radiation interaction processes should be reconsidered. In this paper, I calculate the synchrotron absorption of strong electromagnetic waves.
Theoretical & Experimental Research in Weak, Electromagnetic & Strong Interactions
Energy Technology Data Exchange (ETDEWEB)
Nandi, Satyanarayan [Oklahoma State Univ., Stillwater, OK (United States); Babu, Kaladi [Oklahoma State Univ., Stillwater, OK (United States); Rizatdinova, Flera [Oklahoma State Univ., Stillwater, OK (United States); Khanov, Alexander [Oklahoma State Univ., Stillwater, OK (United States); Haley, Joseph [Oklahoma State Univ., Stillwater, OK (United States)
2015-09-17
The conducted research spans a wide range of topics in the theoretical, experimental and phenomenological aspects of elementary particle interactions. Theory projects involve topics in both the energy frontier and the intensity frontier. The experimental research involves energy frontier with the ATLAS Collaboration at the Large Hadron Collider (LHC). In theoretical research, novel ideas going beyond the Standard Model with strong theoretical motivations were proposed, and their experimental tests at the LHC and forthcoming neutrino facilities were outlined. These efforts fall into the following broad categories: (i) TeV scale new physics models for LHC Run 2, including left-right symmetry and trinification symmetry, (ii) unification of elementary particles and forces, including the unification of gauge and Yukawa interactions, (iii) supersummetry and mechanisms of supersymmetry breaking, (iv) superworld without supersymmetry, (v) general models of extra dimensions, (vi) comparing signals of extra dimensions with those of supersymmetry, (vii) models with mirror quarks and mirror leptons at the TeV scale, (viii) models with singlet quarks and singlet Higgs and their implications for Higgs physics at the LHC, (ix) new models for the dark matter of the universe, (x) lepton flavor violation in Higgs decays, (xi) leptogenesis in radiative models of neutrino masses, (xii) light mediator models of non-standard neutrino interactions, (xiii) anomalous muon decay and short baseline neutrino anomalies, (xiv) baryogenesis linked to nucleon decay, and (xv) a new model for recently observed diboson resonance at the LHC and its other phenomenological implications. The experimental High Energy Physics group has been, and continues to be, a successful and productive contributor to the ATLAS experiment at the LHC. Members of the group performed search for gluinos decaying to stop and top quarks, new heavy gauge bosons decaying to top and bottom quarks, and vector-like quarks
Peptide-microgel interactions in the strong coupling regime.
Hansson, Per; Bysell, Helena; Månsson, Ronja; Malmsten, Martin
2012-09-06
The interaction between lightly cross-linked poly(acrylic acid) microgels and oppositely charged peptides was investigated as a function of peptide length, charge density, pH, and salt concentration, with emphasis on the strong coupling regime at high charge contrast. By micromanipulator-assisted light microscopy, the equilibrium volume response of single microgel particles upon oligolysine and oligo(lysine/alanine) absorption could be monitored in a controlled fashion. Results show that microgel deswelling, caused by peptide binding and network neutralization, increases with peptide length (3 attraction between the network chains is described using an exponential force law, and the network elasticity by the inverse Langevin theory. The model was used to calculate the composition of microgels in contact with reservoir solutions of peptides and simple electrolytes. At high electrostatic coupling, the calculated swelling curves were found to display first-order phase transition behavior. The model was demonstrated to capture pH- and electrolyte-dependent microgel swelling, as well as effects of peptide length and charge density on microgel deswelling. The analysis demonstrated that the peptide charge (length), rather than the peptide charge density, determines microgel deswelling. Furthermore, a transition between continuous and discrete network collapse was identified, consistent with experimental results in the present investigations, as well as with results from the literature on microgel deswelling caused by multivalent cations.
Kinetics and Thermodynamics of Reserpine Adsorption onto Strong Acidic Cationic Exchange Fiber
Guo, Zhanjing; Liu, Xiongmin; Huang, Hongmiao
2015-01-01
The kinetics and thermodynamics of the adsorption process of reserpine adsorbed onto the strong acidic cationic exchange fiber (SACEF) were studied by batch adsorption experiments. The adsorption capacity strongly depended on pH values, and the optimum reserpine adsorption onto the SACEF occurred at pH = 5 of reserpine solution. With the increase of temperature and initial concentration, the adsorption capacity increased. The equilibrium was attained within 20 mins. The adsorption process could be better described by the pseudo-second-order model and the Freundlich isotherm model. The calculated activation energy Ea was 4.35 kJ/mol. And the thermodynamic parameters were: 4.97thermodynamic parameters demonstrated that the adsorption was an endothermic, spontaneous and feasible process of physisorption within the temperature range between 283 K and 323 K and the initial concentration range between 100 mg/L and 300 mg/L. All the results showed that the SACEF had a good adsorption performance for the adsorption of reserpine from alcoholic solution. PMID:26422265
Effective Field Theories and Strong Interactions. Final Technical Report
International Nuclear Information System (INIS)
Fleming, Sean
2011-01-01
The framework of Effective Field Theories (EFTs) allows us to describe strong interactions in terms of degrees of freedom relevant to the energy regimes of interest, in the most general way consistent with the symmetries of QCD. Observables are expanded systematically in powers of M lo /M hi , where M lo (M hi ) denotes a low-(high-)energy scale. This organizational principle is referred to as 'power counting'. Terms of increasing powers in the expansion parameter are referred to as leading order (LO), next-to-leading order (NLO), etc. Details of the QCD dynamics not included explicitly are encoded in interaction parameters, or 'low-energy constants' (LECs), which can in principle be calculated from an explicit solution of QCD - for example via lattice simulations- but can also be determined directly from experimental data. QCD has an intrinsic scale M QCD ≅ 1 GeV, at which the QCD coupling constant α s (M QCD ) becomes large and the dynamics becomes non-perturbative. As a consequence M QCD sets the scale for the masses of most hadrons, such as the nucleon mass m N ≅ 940 MeV. EFTs can roughly be divided into two categories: those that can be matched onto QCD in perturbation theory, which we call high-energy EFTs, and those that cannot be matched perturbatively, which we call low-energy EFTs. In high-energy EFTs, M QCD typically sets the low-energy scale, and all the dynamics associated with this scale reside in matrix elements of EFT operators. These non-perturbative matrix elements are the LECs and are also referred to as long-distance contributions. Each matrix element is multiplied by a short-distance coefficient, which contains the dynamics from the high scale M hi . Since M hi >> M QCD , α s (M hi ) hi ∼ M Q , the heavy-quark mass, and in addition to M QCD there are low scales associated with the typical relative momentum ∼ M Q v and energy ∼ M Q v 2 of the heavy quarks. Depending on the sizes of M Q and the heavy-quark velocity v these scales can
Strongly interacting matter at high densities with a soliton model
Johnson, Charles Webster
1998-12-01
One of the major goals of modern nuclear physics is to explore the phase diagram of strongly interacting matter. The study of these 'extreme' conditions is the primary motivation for the construction of the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory which will accelerate nuclei to a center of mass (c.m.) energy of about 200 GeV/nucleon. From a theoretical perspective, a test of quantum chromodynamics (QCD) requires the expansion of the conditions examined from one phase point to the entire phase diagram of strongly-interacting matter. In the present work we focus attention on what happens when the density is increased, at low excitation energies. Experimental results from the Brookhaven Alternating Gradient Synchrotron (AGS) indicate that this regime may be tested in the 'full stopping' (maximum energy deposition) scenario achieved at the AGS having a c.m. collision energy of about 2.5 GeV/nucleon for two equal- mass heavy nuclei. Since the solution of QCD on nuclear length-scales is computationally prohibitive even on today's most powerful computers, progress in the theoretical description of high densities has come through the application of models incorporating some of the essential features of the full theory. The simplest such model is the MIT bag model. We use a significantly more sophisticated model, a nonlocal confining soliton model developed in part at Kent. This model has proven its value in the calculation of the properties of individual mesons and nucleons. In the present application, the many-soliton problem is addressed with the same model. We describe nuclear matter as a lattice of solitons and apply the Wigner-Seitz approximation to the lattice. This means that we consider spherical cells with one soliton centered in each, corresponding to the average properties of the lattice. The average density is then varied by changing the size of the Wigner-Seitz cell. To arrive at a solution, we need to solve a coupled set of
Interaction effects in a microscopic quantum wire model with strong spin-orbit interaction
Winkler, G. W.; Ganahl, M.; Schuricht, D.; Evertz, H. G.; Andergassen, S.
2017-06-01
We investigate the effect of strong interactions on the spectral properties of quantum wires with strong Rashba spin-orbit (SO) interaction in a magnetic field, using a combination of matrix product state and bosonization techniques. Quantum wires with strong Rashba SO interaction and magnetic field exhibit a partial gap in one-half of the conducting modes. Such systems have attracted wide-spread experimental and theoretical attention due to their unusual physical properties, among which are spin-dependent transport, or a topological superconducting phase when under the proximity effect of an s-wave superconductor. As a microscopic model for the quantum wire we study an extended Hubbard model with SO interaction and Zeeman field. We obtain spin resolved spectral densities from the real-time evolution of excitations, and calculate the phase diagram. We find that interactions increase the pseudo gap at k = 0 and thus also enhance the Majorana-supporting phase and stabilize the helical spin order. Furthermore, we calculate the optical conductivity and compare it with the low energy spiral Luttinger liquid result, obtained from field theoretical calculations. With interactions, the optical conductivity is dominated by an excotic excitation of a bound soliton-antisoliton pair known as a breather state. We visualize the oscillating motion of the breather state, which could provide the route to their experimental detection in e.g. cold atom experiments.
The colours of strong interaction; L`interaction forte sous toutes ses couleurs
Energy Technology Data Exchange (ETDEWEB)
NONE
1995-12-31
The aim of this session is to draw a consistent framework about the different ways to consider strong interaction. A large part is dedicated to theoretical work and the latest experimental results obtained at the first electron collider HERA are discussed. (A.C.)
Kinetics of chemical interactions between zirconium alloys and stainless steels
International Nuclear Information System (INIS)
Frecska, J.; Maroti, L.; Matus, L.
1995-01-01
The chemical interaction kinetics of reactor core component zirconium alloys and stainless steels at high temperatures was examined. Interaction of as-received and preoxidized Zr1%Nb with X18H10T stainless steel used in WWER type nuclear reactors, and also that of Zircaloy-4 and AISI-316 stainless steel, for comparison, were investigated. The reaction rate measurements were supplemented with post-test metallographical examinations. Results are presented and evaluated, and compared with literature data. (author). 14 refs., 31 figs., 8 tabs
Interaction of neutral particles with strong laser fields
Energy Technology Data Exchange (ETDEWEB)
Meuren, Sebastian; Keitel, Christoph H.; Di Piazza, Antonino [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany)
2013-07-01
Since the invention of the laser in the 1960s the experimentally available field strengths have continuously increased. The current peak intensity record is 2 x 10{sup 22} W/cm{sup 2} and next generation facilities such as ELI, HiPER and XCELS plan to reach even intensities of the order of 10{sup 24} W/cm{sup 2}. Thus, modern laser facilities are a clean source for very strong external electromagnetic fields and promise new and interesting high-energy physics experiments. In particular, strong laser fields could be used to test non-linear effects in quantum field theory. Earlier we have investigated how radiative corrections modify the coupling of a charged particle inside a strong plane-wave electromagnetic background field. However, a charged particle couples already at tree level to electromagnetic radiation. Therefore, we have now analyzed how the coupling between neutral particles and radiation is affected by a very strong plane-wave electromagnetic background field, when loop corrections are taken into account. In particular, the case of neutrinos is discussed.
Intensities and strong interaction attenuation of kaonic x-rays
Backenstoss, Gerhard; Koch, H; Povel, H P; Schwitter, A; Tauscher, Ludwig
1974-01-01
Relative intensities of numerous kaonic X-ray transitions have been measured for the elements C, P, S, and Cl, from which level widths due to the strong K-nucleus absorption have been determined. From these and earlier published data, optical potential parameters have been derived and possible consequences on the nuclear matter distribution are discussed. (10 refs).
Dynamical fermion mass generation by a strong Yukawa interaction
Czech Academy of Sciences Publication Activity Database
Brauner, Tomáš; Hošek, Jiří
2005-01-01
Roč. 72, č. 4 (2005), 045007 ISSN 0556-2821 R&D Projects: GA MŠk LA 080; GA ČR(CZ) GD202/05/H003 Institutional research plan: CEZ:AV0Z10480505 Keywords : dynamical mass generation * Yukawa interaction Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 4.852, year: 2005
Gauge theories of weak, electromagnetic and strong interactions
International Nuclear Information System (INIS)
Boehm, M.; Joos, H.
1978-05-01
This 10 lectures are devided into the chapters: Phenomenological basis of the quantum chromodynamics, phenomenology of weak interactions, quantum electrodynamics and gauge invariance, from the fermimodel to the quantum flavor dynamics, on the quantum theory of yang-mills-fields, spontaneous symmetry breaking - the Higgs-Kibble-mechanism, the Salam-Weinberg-model, asymptotic freedom, quark confinement and charmonium. (WL) [de
Physics Performance Report for PANDA : Strong Interaction Studies with Antiprotons
Erni, W.; Keshelashvili, I.; Krusche, B.; Steinacher, M.; Heng, Y.; Liu, Z.; Liu, H.; Shen, X.; Wang, O.; Xu, H.; Becker, J.; Feldbauer, F.; Heinsius, F. -H.; Held, T.; Koch, H.; Kopf, B.; Pelizaeus, M.; Schroeder, T.; Steinke, M.; Wiedner, U.; Zhong, J.; Bianconi, A.; Bragadireanu, M.; Pantea, D.; Tudorache, A.; Tudorache, V.; De Napoli, M.; Giacoppo, F.; Raciti, G.; Rapisarda, E.; Sfienti, C.; Bialkowski, E.; Budzanowski, A.; Czech, B.; Kistryn, M.; Kliczewski, S.; Kozela, A.; Kulessa, P.; Pysz, K.; Schaefer, W.; Siudak, R.; Szczurek, A.; Czy. zycki, W.; Domagala, M.; Hawryluk, M.; Lisowski, E.; Lisowski, F.; Wojnar, L.; Gil, D.; Hawranek, P.; Kamys, B.; Kistryn, St.; Korcyl, K.; Krzemien, W.; Magiera, A.; Moskal, P.; Rudy, Z.; Salabura, P.; Smyrski, J.; Wronska, A.; Al-Turany, M.; Augustin, I.; Deppe, H.; Flemming, H.; Gerl, J.; Goetzen, K.; Hohler, R.; Lehmann, D.; Lewandowski, B.; Luehning, J.; Maas, F.; Mishra, D.; Orth, H.; Peters, K.; Saito, T.; Schepers, G.; Schmidt, C. J.; Schmitt, L.; Schwarz, C.; Voss, B.; Wieczorek, P.; Wilms, A.; Brinkmann, K. -T.; Freiesleben, H.; Jaekel, R.; Kliemt, R.; Wuerschig, T.; Zaunick, H. -G.; Abazov, V. M.; Alexeev, G.; Arefiev, A.; Astakhov, V. I.; Barabanov, M. Yu.; Batyunya, B. V.; Davydov, Yu. I.; Dodokhov, V. Kh.; Efremov, A. A.; Fedunov, A. G.; Feshchenko, A. A.; Galoyan, A. S.; Grigoryan, S.; Karmokov, A.; Koshurnikov, E. K.; Kudaev, V. Ch.; Lobanov, V. I.; Lobanov, Yu. Yu.; Makarov, A. F.; Malinina, L. V.; Malyshev, V. L.; Mustafaev, G. A.; Olshevski, A.; . Pasyuk, M. A.; Perevalova, E. A.; Piskun, A. A.; Pocheptsov, T. A.; Pontecorvo, G.; Rodionov, V. K.; Rogov, Yu. N.; Salmin, R. A.; Samartsev, A. G.; Sapozhnikov, M. G.; Shabratova, A.; Shabratova, G. S.; Skachkova, A. N.; Skachkov, N. B.; Strokovsky, E. A.; Suleimanov, M. K.; Teshev, R. Sh.; Tokmenin, V. V.; Uzhinsky, V. V.; Vodopianov, A. S.; Zaporozhets, S. A.; Zhuravlev, N. I.; Zorin, A. G.; Branford, D.; Foehl, K.; Glazier, D.; Watts, D.; Woods, P.; Eyrich, W.; Lehmann, A.; Teufel, A.; Dobbs, S.; Metreveli, Z.; Seth, K.; Tann, B.; Tomaradze, A.; Bettoni, D.; Carassiti, V.; Cecchi, A.; Dalpiaz, P.; Fioravanti, E.; Garzia, I.; Negrini, M.; Savri`e, M.; Stancari, G.; Dulach, B.; Gianotti, P.; Guaraldo, C.; Lucherini, V.; Pace, E.; Bersani, A.; Macri, M.; Marinelli, M.; Parodi, R. F.; Brodski, I.; Doering, W.; Drexler, P.; Dueren, M.; Gagyi-Palffy, Z.; Hayrapetyan, A.; Kotulla, M.; Kuehn, W.; Lange, S.; Liu, M.; Metag, V.; Nanova, M.; Novotny, R.; Salz, C.; Schneider, J.; Schoenmeier, P.; Schubert, R.; Spataro, S.; Stenzel, H.; Strackbein, C.; Thiel, M.; Thoering, U.; Yang, S.; Clarkson, T.; Cowie, E.; Downie, E.; Hill, G.; Hoek, M.; Ireland, D.; Kaiser, R.; Keri, T.; Lehmann, I.; Livingston, K.; Lumsden, S.; MacGregor, D.; McKinnon, B.; Murray, M.; Protopopescu, D.; Rosner, G.; Seitz, B.; Yang, G.; Babai, M.; Biegun, A. K.; Bubak, A.; Guliyev, E.; Suyam Jothi, Vanniarajan; Kavatsyuk, M.; Loehner, H.; Messchendorp, J.; Smit, H.; van der Weele, J. C.; Garcia, F.; Riska, D. -O.; Buescher, M.; Dosdall, R.; Dzhygadlo, R.; Gillitzer, A.; Grunwald, D.; Jha, V.; Kemmerling, G.; Kleines, H.; Lehrach, A.; Maier, R.; Mertens, M.; Ohm, H.; Prasuhn, D.; Randriamalala, T.; Ritman, J.; Roeder, M.; Stockmanns, T.; Wintz, P.; Wuestner, P.; Kisiel, J.; Li, S.; Li, Z.; Sun, Z.; Xu, H.; Fissum, S.; Hansen, K.; Isaksson, L.; Lundin, M.; Schroeder, B.; Achenbach, P.; Mora Espi, M. C.; Pochodzalla, J.; Sanchez, S.; Sanchez-Lorente, A.; Dormenev, V. I.; Fedorov, A. A.; Korzhik, M. V.; Missevitch, O. V.; Balanutsa, V.; Chernetsky, V.; Demekhin, A.; Dolgolenko, A.; Fedorets, P.; Gerasimov, A.; Goryachev, V.; Boukharov, A.; Malyshev, O.; Marishev, I.; Semenov, A.; Hoeppner, C.; Ketzer, B.; Konorov, I.; Mann, A.; Neubert, S.; Paul, S.; Weitzel, Q.; Khoukaz, A.; Rausmann, T.; Taeschner, A.; Wessels, J.; Varma, R.; Baldin, E.; Kotov, K.; Peleganchuk, S.; Tikhonov, Yu.; Boucher, J.; Hennino, T.; Kunne, R.; Ong, S.; Pouthas, J.; Ramstein, B.; Rosier, P.; Sudol, M.; Van de Wiele, J.; Zerguerras, T.; Dmowski, K.; Korzeniewski, R.; Przemyslaw, D.; Slowinski, B.; Boca, G.; Braghieri, A.; Costanza, S.; Fontana, A.; Genova, P.; Lavezzi, L.; Montagna, P.; Rotondi, A.; Belikov, N. I.; Davidenko, A. M.; Derevschikov, A. A.; Goncharenko, Y. M.; Grishin, V. N.; Kachanov, V. A.; Konstantinov, D. A.; Kormilitsin, V. A.; Kravtsov, V. I.; Matulenko, Y. A.; Melnik, Y. M.; Meschanin, A. P.; Minaev, N. G.; Mochalov, V. V.; Morozov, D. A.; Nogach, L. V.; Nurushev, S. B.; Ryazantsev, A. V.; Semenov, P. A.; Soloviev, L. F.; Uzunian, A. V.; Vasiliev, A. N.; Yakutin, A. E.; Baeck, T.; Cederwall, B.; Bargholtz, C.; Geren, L.; Tegner, P. E.; Belostotski, S.; Gavrilov, G.; Itzotov, A.; Kisselev, A.; Kravchenko, P.; Manaenkov, S.; Miklukho, O.; Naryshkin, Y.; Veretennikov, D.; Vikhrov, V.; Zhadanov, A.; Fava, L.; Panzieri, D.; Alberto, D.; Amoroso, A.; Botta, E.; Bressani, T.; Bufalino, S.; Bussa, M. P.; Busso, L.; De Mori, F.; Destefanis, M.; Ferrero, L.; Grasso, A.; Greco, M.; Kugathasan, T.; Maggiora, M.; Marcello, S.; Serbanut, G.; Sosio, S.; Bertini, R.; Calvo, D.; Coli, S.; De Remigis, P.; Feliciello, A.; Filippi, A.; Giraudo, G.; Mazza, G.; Rivetti, A.; Szymanska, K.; Tosello, F.; Wheadon, R.; Morra, O.; Agnello, M.; Iazzi, F.; Szymanska, K.; Birsa, R.; Bradamante, F.; Bressan, A.; Martin, A.; Clement, H.; Ekstroem, C.; Calen, H.; Grape, S.; Hoeistad, B.; Johansson, T.; Kupsc, A.; Marciniewski, P.; Thome, E.; Zlomanczuk, J.; Diaz, J.; Ortiz, A.; Borsuk, S.; Chlopik, A.; Guzik, Z.; Kopec, J.; Kozlowski, T.; Melnychuk, D.; Plominski, M.; Szewinski, J.; Traczyk, K.; Zwieglinski, B.; Buehler, P.; Gruber, A.; Kienle, P.; Marton, J.; Widmann, E.; Zmeskal, J.; Lutz, M. F. M.; Pire, B.; Scholten, O.; Timmermans, R.
To study fundamental questions of hadron and nuclear physics in interactions of antiprotons with nucleons and nuclei, the universal PANDA detector will be built. Gluonic excitations, the physics of strange and charm quarks and nucleon structure studies will be performed with unprecedented accuracy
Coulomb plus strong interaction bound states - momentum space numerical solutions
International Nuclear Information System (INIS)
Heddle, D.P.; Tabakin, F.
1985-01-01
The levels and widths of hadronic atoms are calculated in momentum space using an inverse algorithm for the eigenvalue problem. The Coulomb singularity is handled by the Lande substraction method. Relativistic, nonlocal, complex hadron-nucleus interactions are incorporated as well as vacuum polarization and finite size effects. Coordinate space wavefunctions are obtained by employing a Fourier Bessel transformation. (orig.)
Many-body Anderson localization of strongly interacting bosons in random lattices
International Nuclear Information System (INIS)
Katzer, Roman
2015-05-01
In the present work, we investigate the problem of many-body localization of strongly interacting bosons in random lattices within the disordered Bose-Hubbard model. This involves treating both the local Mott-Hubbard physics as well as the non-local quantum interference processes, which give rise to the phenomenon of Anderson localization, within the same theory. In order to determine the interaction induced transition to the Mott insulator phase, it is necessary to treat the local particle interaction exactly. Therefore, here we use a mean-field approach that approximates only the kinetic term of the Hamiltonian. This way, the full problem of interacting bosons on a random lattice is reduced to a local problem of a single site coupled to a particle bath, which has to be solved self-consistently. In accordance to previous works, we find that a finite disorder width leads to a reduced size of the Mott insulating regions. The transition from the superfluid phase to the Bose glass phase is driven by the non-local effect of Anderson localization. In order to describe this transition, one needs to work within a theory that is non-local as well. Therefore, here we introduce a new approach to the problem. Based on the results for the local excitation spectrum obtained within the mean-field theory, we reduce the full, interacting model to an effective, non-interacting model by applying a truncation scheme to the Hilbert space. Evaluating the long-ranged current density within this approximation, we identify the transition from the Bose glass to the superfluid phase with the Anderson transition of the effective model. Resolving this transition using the self-consistent theory of localization, we obtain the full phase diagram of the disordered Bose-Hubbard model in the regime of strong interaction and larger disorder. In accordance to the theorem of inclusions, we find that the Mott insulator and the superfluid phase are always separated by the compressible, but insulating
Quantum memory with strong and controllable Rydberg-level interactions.
Li, Lin; Kuzmich, A
2016-11-21
Realization of distributed quantum systems requires fast generation and long-term storage of quantum states. Ground atomic states enable memories with storage times in the range of a minute, however their relatively weak interactions do not allow fast creation of non-classical collective states. Rydberg atomic systems feature fast preparation of singly excited collective states and their efficient mapping into light, but storage times in these approaches have not yet exceeded a few microseconds. Here we demonstrate a system that combines fast quantum state generation and long-term storage. An initially prepared coherent state of an atomic memory is transformed into a non-classical collective atomic state by Rydberg-level interactions in less than a microsecond. By sheltering the quantum state in the ground atomic levels, the storage time is increased by almost two orders of magnitude. This advance opens a door to a number of quantum protocols for scalable generation and distribution of entanglement.
Hadron yields and the phase diagram of strongly interacting matter
Floris, Michele
2014-01-01
This paper presents a brief review of the interpretation of measurements of hadron yields in hadronic interactions within the framework of thermal models, over a broad energy range (from SIS to LHC energies, $\\sqrt{s_{NN}} \\simeq$ 2.5 GeV -- 5 TeV). Recent experimental results and theoretical developments are reported, with an emphasis on topics discussed during the Quark Matter 2014 conference.
Theoretical studies in weak, electromagnetic and strong interactions. Attachments
International Nuclear Information System (INIS)
Nandi, S.
1999-01-01
The project covered a wide area of current research in theoretical high-energy physics. This included Standard Model (SM) as well as physics beyond the Standard Model. Specific topics included supersymmetry (SUSY), perturbative quantum chromodynamics (QCD), a new weak interaction for the third family (called topflavor), neutrino masses and mixings, topcolor model, Pade approximation, and its application to perturbative QCD and other physical processes
Conner, Kyle M; Arostegui, AnnaMaria C; Swanson, Daniel D; Brown, Seth N
2018-03-08
The 2,2'-biphenylene-bridged bis(iminosemiquinone) complexes ( t BuClip)M [ t BuClipH 4 = 4,4'-di- tert-butyl- N, N'-bis(3,5-di- tert-butyl-2-hydroxyphenyl)-2,2'-diaminobiphenyl; M = Pd, Pt] can be reduced to the bis(aminophenoxide) complexes ( t BuClipH 2 )M by reaction with hydrazobenzene (M = Pd) or by catalytic hydrogenation (M = Pt). The palladium complex with one aminophenoxide ligand and one iminosemiquinone ligand, ( t BuClipH)Pd, is generated by comproportionation of ( t BuClip)Pd with ( t BuClipH 2 )Pd in a process that is both slow (0.06 M -1 s -1 in toluene at 23 °C) and only modestly favorable ( K com = 1.9 in CDCl 3 ), indicating that both N-H bonds have essentially the same bond strength. The mono(iminoquinone) complex ( t BuClipH)Pt has not been observed, indicating that the platinum analogue shows no tendency to comproportionate ( K com < 0.1). The average bond dissociation free energies (BDFE) of the complexes have been established by equilibration with suitably substituted hydrazobenzenes, and the palladium bis(iminosemiquinone) is markedly more oxidizing than the platinum compound, with hydrogen transfer from ( t BuClipH 2 )Pt to ( t BuClip)Pd occurring with Δ G° = -8.9 kcal mol -1 . The palladium complex ( t BuClipH 2 )Pd reacts with nitroxyl radicals in two observable steps, with the first hydrogen transfer taking place slightly faster than the second. In the platinum analogue, the first hydrogen transfer is much slower than the second, presumably because the N-H bond in the monoradical complex ( t BuClipH)Pt is unusually weak. Using driving force-rate correlations, it is estimated that this bond has a BDFE of 55.1 kcal mol -1 , which is 7.1 kcal mol -1 weaker than that of the first N-H bond in ( t BuClipH 2 )Pt. The two radical centers in the platinum, but not the palladium, complex thus act in concert with each other and display a strong thermodynamic bias toward two-electron reactivity. The greater thermodynamic and kinetic coupling in
Muons probe strong hydrogen interactions with defective graphene.
Riccò, Mauro; Pontiroli, Daniele; Mazzani, Marcello; Choucair, Mohammad; Stride, John A; Yazyev, Oleg V
2011-11-09
Here, we present the first muon spectroscopy investigation of graphene, focused on chemically produced, gram-scale samples, appropriate to the large muon penetration depth. We have observed an evident muon spin precession, usually the fingerprint of magnetic order, but here demonstrated to originate from muon-hydrogen nuclear dipolar interactions. This is attributed to the formation of CHMu (analogous to CH(2)) groups, stable up to 1250 K where the signal still persists. The relatively large signal amplitude demonstrates an extraordinary hydrogen capture cross section of CH units. These results also rule out the formation of ferromagnetic or antiferromagnetic order in chemically synthesized graphene samples.
Interaction of Azobenzene and Benzalaniline with Strong Amido Bases.
Kornev, Alexander N; Sushev, Vyacheslav V; Zolotareva, Natalia V; Baranov, Evgenii V; Fukin, Georgy K; Abakumov, Gleb A
2015-12-18
The interaction of azobenzene with lithium dicyclohexylamide (Cy2NLi) in THF or Et2O afforded the ion-radical salt of azobenzene (1) structurally characterized for the first time and dicyclohexylaminyl radical, which begins a novel chain of transformations leading eventually to the imino-enamido lithium complex (3). Benzalaniline, being a relative of azobenzene, reacted with Cy2NLi without electron transfer by a proton-abstraction mechanism to form the dilithium salt of N(1),N(2),1,2-tetraphenylethene-1,2-diamine quantitatively.
Spin effects in strong-field laser-electron interactions
International Nuclear Information System (INIS)
Ahrens, S; Bauke, H; Müller, T-O; Villalba-Chávez, S; Müller, C
2013-01-01
The electron spin degree of freedom can play a significant role in relativistic scattering processes involving intense laser fields. In this contribution we discuss the influence of the electron spin on (i) Kapitza-Dirac scattering in an x-ray laser field of high intensity, (ii) photo-induced electron-positron pair production in a strong laser wave and (iii) multiphoton electron-positron pair production on an atomic nucleus. We show that in all cases under consideration the electron spin can have a characteristic impact on the process properties and their total probabilities. To this end, spin-resolved calculations based on the Dirac equation in the presence of an intense laser field are performed. The predictions from Dirac theory are also compared with the corresponding results from the Klein-Gordon equation.
Strongly-interacting mirror fermions at the LHC
Directory of Open Access Journals (Sweden)
Triantaphyllou George
2017-01-01
Full Text Available The introduction of mirror fermions corresponding to an interchange of leftwith right-handed fermion quantum numbers of the Standard Model can lead to a model according to which the BEH mechanism is just an effective manifestation of a more fundamental theory while the recently-discovered Higgs-like particle is composite. This is achieved by a non-abelian gauge symmetry encompassing three mirror-fermion families strongly coupled at energies near 1 TeV. The corresponding non-perturbative dynamics lead to dynamical mirror-fermion masses between 0.14 - 1.2 TeV. Furthermore, one expects the formation of composite states, i.e. “mirror mesons”, with masses between 0.1 and 3 TeV. The number and properties of the resulting new degrees of freedom lead to a rich and interesting phenomenology, part of which is analyzed in the present work.
A non-linear theory of strong interactions
International Nuclear Information System (INIS)
Skyrme, T.H.R.
1994-01-01
A non-linear theory of mesons, nucleons and hyperons is proposed. The three independent fields of the usual symmetrical pseudo-scalar pion field are replaced by the three directions of a four-component field vector of constant length, conceived in an Euclidean four-dimensional isotopic spin space. This length provides the universal scaling factor, all other constants being dimensionless; the mass of the meson field is generated by a φ 4 term; this destroys the continuous rotation group in the iso-space, leaving a 'cubic' symmetry group. Classification of states by this group introduces quantum numbers corresponding to isotopic spin and to 'strangeness'; one consequences is that, at least in elementary interactions, charge is only conserved module 4. Furthermore, particle states have not a well-defined parity, but parity is effectively conserved for meson-nucleon interactions. A simplified model, using only two dimensions of space and iso-space, is considered further; the non-linear meson field has solutions with particle character, and an indication is given of the way in which the particle field variables might be introduced as collective co-ordinates describing the dynamics of these particular solutions of the meson field equations, suggesting a unified theory based on the meson field alone. (author). 7 refs
Bao, Jiayin; Krylova, Svetlana M; Reinstein, Oren; Johnson, Philip E; Krylov, Sergey N
2011-11-15
Here we demonstrate a label-free solution-based approach for studying the kinetics of biopolymer-small molecule interactions. The approach utilizes kinetic capillary electrophoresis (KCE) separation and UV light absorption detection of the unlabeled small molecule. In this proof-of-concept work, we applied KCE-UV to study kinetics of interaction between a small molecule and a DNA aptamer. From the kinetic analysis of a series of aptamers, we found that dissociation rather than binding controls the stability of the complex. Because of its label-free features and generic nature, KCE-UV promises to become a practical tool for challenging kinetic studies of biopolymer-small molecule interactions.
Magnetic dynamics of weakly and strongly interacting hematite nanoparticles
DEFF Research Database (Denmark)
Hansen, Mikkel Fougt; Bender Koch, Christian; Mørup, Steen
2000-01-01
The magnetic dynamics of two differently treated samples of hematite nanoparticles from the same batch with a particle size of about 20 nm have been studied by Mossbauer spectroscopy. The dynamics of the first sample, in which the particles are coated and dispersed in water, is in accordance.......3(-0.8)(+1.0) x 10(-10) s for a rotation of the sublattice magnetization directions in the rhombohedral (111) plane. The corresponding median superparamagnetic blocking temperature is about 150 K. The dynamics of the second, dry sample, in which the particles are uncoated and thus allowed to aggregate, is slowed...... down by interparticle interactions and a magnetically split spectrum is retained at room temperature. The temperature variation or the magnetic hyperfine field, corresponding to different quantiles in the hyperfine field distribution, can be consistently described by a mean field model...
Light and neutron scattering study of strongly interacting ionic micelles
International Nuclear Information System (INIS)
Degiorgio, V.; Corti, M.; Piazza, R.
1989-01-01
Dilute solutions of ionic micelles formed by biological glycolipids (gangliosides) have been investigated at various ionic strengths by static and dynamic light scaterring and by small-angle neutron scattering. The size and shape of the micelle is not appreciably affected by the added salt concentration in the range 0-100 mM NaCL. From the measured intensity of scattered light we derive the electric charge Z of the micelle by fitting the data to a theoretical calculation which uses a screened Coulomb potential for the intermicellar interaction, and the hypernetted chain approximation for the calculation of the radial distribution function. The correlation function derived from dynamic light scattering shows the long time contribution typical of concentrated polydisperse systems (author). 15 refs.; 6 figs
Strong delayed interactive effects of metal exposure and warming
DEFF Research Database (Denmark)
Debecker, Sara; Dinh, Khuong Van; Stoks, Robby
2017-01-01
As contaminants are often more toxic at higher temperatures, predicting their impact under global warming remains a key challenge for ecological risk assessment. Ignoring delayed effects, synergistic interactions between contaminants and warming, and differences in sensitivity across species......’ ranges could lead to an important underestimation of the risks. We addressed all three mechanisms by studying effects of larval exposure to zinc and warming before, during, and after metamorphosis in Ischnura elegans damselflies from high- and lowlatitude populations. By integrating these mechanisms...... was especially remarkable in high-latitude animals, as they appeared almost insensitive to zinc during the larval stage. Second, the well-known synergism between metals and warming was manifested not only during the larval stage but also after metamorphosis, yet notably only in low-latitude damselflies...
Fourier heat conduction as a strong kinetic effect in one-dimensional hard-core gases
Zhao, Hanqing; Wang, Wen-ge
2018-01-01
For a one-dimensional (1D) momentum conserving system, intensive studies have shown that generally its heat current autocorrelation function (HCAF) tends to decay in a power-law manner and results in the breakdown of the Fourier heat conduction law in the thermodynamic limit. This has been recognized to be a dominant hydrodynamic effect. Here we show that, instead, the kinetic effect can be dominant in some cases and leads to the Fourier law for finite-size systems. Usually the HCAF undergoes a fast decaying kinetic stage followed by a long slowly decaying hydrodynamic tail. In a finite range of the system size, we find that whether the system follows the Fourier law depends on whether the kinetic stage dominates. Our Rapid Communication is illustrated by the 1D hard-core gas models with which the HCAF is derived analytically and verified numerically by molecular dynamics simulations.
Natural Cold Baryogenesis from Strongly Interacting Electroweak Symmetry Breaking
Konstandin, Thomas
2011-01-01
The mechanism of "cold electroweak baryogenesis" has been so far unpopular because its proposal has relied on the ad-hoc assumption of a period of hybrid inflation at the electroweak scale with the Higgs acting as the waterfall field. We argue here that cold baryogenesis can be naturally realized without the need to introduce any slow-roll potential. Our point is that composite Higgs models where electroweak symmetry breaking arises via a strongly first-order phase transition provide a well-motivated framework for cold baryogenesis. In this case, reheating proceeds by bubble collisions and we argue that this can induce changes in Chern-Simons number, which in the presence of new sources of CP violation commonly lead to baryogenesis. We illustrate this mechanism using as a source of CP violation an effective dimension-six operator which is free from EDM constraints, another advantage of cold baryogenesis compared to the standard theory of electroweak baryogenesis. Our results are general as they do not rely on...
Exact tensor network ansatz for strongly interacting systems
Zaletel, Michael P.
It appears that the tensor network ansatz, while not quite complete, is an efficient coordinate system for the tiny subset of a many-body Hilbert space which can be realized as a low energy state of a local Hamiltonian. However, we don't fully understand precisely which phases are captured by the tensor network ansatz, how to compute their physical observables (even numerically), or how to compute a tensor network representation for a ground state given a microscopic Hamiltonian. These questions are algorithmic in nature, but their resolution is intimately related to understanding the nature of quantum entanglement in many-body systems. For this reason it is useful to compute the tensor network representation of various `model' wavefunctions representative of different phases of matter; this allows us to understand how the entanglement properties of each phase are expressed in the tensor network ansatz, and can serve as test cases for algorithm development. Condensed matter physics has many illuminating model wavefunctions, such as Laughlin's celebrated wave function for the fractional quantum Hall effect, the Bardeen-Cooper-Schrieffer wave function for superconductivity, and Anderson's resonating valence bond ansatz for spin liquids. This thesis presents some results on exact tensor network representations of these model wavefunctions. In addition, a tensor network representation is given for the time evolution operator of a long-range one-dimensional Hamiltonian, which allows one to numerically simulate the time evolution of power-law interacting spin chains as well as two-dimensional strips and cylinders.
Strong impact of ionic strength on the kinetics of fibrilar aggregation of bovine beta-lactoglobulin
Arnaudov, L.N.; Vries, de R.J.
2006-01-01
We investigate the effect of ionic strength on the kinetics of heat-induced fibrilar aggregation of bovine -lactoglobulin at pH 2.0. Using in situ light scattering we find an apparent critical protein concentration below which there is no significant fibril formation for all ionic strengths studied.
Study of the interaction of atoms with strong laser fields
International Nuclear Information System (INIS)
Edwards, M.
1984-01-01
Three aspects of the interactions of atoms with high intensity laser fields were treated. All three were motivated by experiment. The first investigation was prompted by a recent experiment (Kruit et al. 1983) involving multiphoton ionization of Xe. In this experiment it was found that the photoelectron energy spectrum contained peaks that corresponded to the absorption of more than the minimum number of photons required to ionize the atom. A model approximation here showed good qualitative agreement with experiment. An experiment (Grove et al. 1977) designed to test a theoretical calculation of the dynamical Stark effect stimulated the second part of this thesis, namely: a study of how an adiabatically and near-adiabatically changing field intensity affects the resonance fluorescence spectrum of a two-level atom. It was found that there is an asymmetry in the spectrum for off-resonance excitation produced because the field turn-on repopulates the dressed state that is depopulated by spontaneous emission. The third part of this thesis was based on an experiment (Granneman and Van der Wiel 1976) that attempted to verify a perturbation calculation of the two-photon ionization cross section of Cs. A discrepancy of four orders of magnitude near a minimum in the cross section was found between theory and experiment. To explain this discrepancy it was suggested (Armstrong and Beers 1977) that the effective order of nonlinearity (k) for this process varied significantly around the minimum. This study involves a perturbation calculation of k. It was found that k varies rapidly around the minimum, and that this variation should be experimentally observable for laser intensities of the order of tens of GW cm -2
DEFF Research Database (Denmark)
Bellotti, Filipe Furlan; Salami Dehkharghani, Amin; Zinner, Nikolaj Thomas
2017-01-01
We investigate one-dimensional harmonically trapped two-component systems for repulsive interaction strengths ranging from the non-interacting to the strongly interacting regime for Fermi-Fermi mixtures. A new and powerful mapping between the interaction strength parameters from a continuous...
Asymptotic Completeness for Relativistic Kinetic Equations with Short-range Interaction Forces
Ha, Seung-Yeal; Kim, Yong Duck; Lee, Ho; Noh, Se Eun
2007-01-01
We present an $L^1$-asymptotic completeness results for relativistic kinetic equations with short range interaction forces. We show that the uniform phase space-time bound for nonlinear terms to the relativistic nonlinear kinetic equations yields the asymptotic completeness of the relativistic kinetic equations. For this space-time bound, we employ dispersive estimates and explicit construction of a Lyapunov functional.
Hyperspherical Treatment of Strongly-Interacting Few-Fermion Systems in One Dimension
DEFF Research Database (Denmark)
Volosniev, A. G.; Fedorov, D. V.; Jensen, A. S.
2015-01-01
We examine a one-dimensional two-component fermionic system in a trap, assuming that all particles have the same mass and interact through a strong repulsive zero-range force. First we show how a simple system of three strongly interacting particles in a harmonic trap can be treated using...
Effects of electrostatic interactions on ligand dissociation kinetics
Erbaş, Aykut; de la Cruz, Monica Olvera; Marko, John F.
2018-02-01
We study unbinding of multivalent cationic ligands from oppositely charged polymeric binding sites sparsely grafted on a flat neutral substrate. Our molecular dynamics simulations are suggested by single-molecule studies of protein-DNA interactions. We consider univalent salt concentrations spanning roughly a 1000-fold range, together with various concentrations of excess ligands in solution. To reveal the ionic effects on unbinding kinetics of spontaneous and facilitated dissociation mechanisms, we treat electrostatic interactions both at a Debye-Hückel (DH) (or implicit ions, i.e., use of an electrostatic potential with a prescribed decay length) level and by the more precise approach of considering all ionic species explicitly in the simulations. We find that the DH approach systematically overestimates unbinding rates, relative to the calculations where all ion pairs are present explicitly in solution, although many aspects of the two types of calculation are qualitatively similar. For facilitated dissociation (FD) (acceleration of unbinding by free ligands in solution) explicit-ion simulations lead to unbinding at lower free-ligand concentrations. Our simulations predict a variety of FD regimes as a function of free-ligand and ion concentrations; a particularly interesting regime is at intermediate concentrations of ligands where nonelectrostatic binding strength controls FD. We conclude that explicit-ion electrostatic modeling is an essential component to quantitatively tackle problems in molecular ligand dissociation, including nucleic-acid-binding proteins.
Critical Behavior of a Strongly-Interacting 2D Electron System
Sarachik, Myriam P.
2013-03-01
Two-dimensional (2D) electron systems that obey Fermi liquid theory at high electron densities are expected to undergo one or more transitions to spatially and/or spin-ordered phases as the density is decreased, ultimately forming a Wigner crystal in the dilute, strongly-interacting limit. Interesting, unexpected behavior is observed with decreasing electron density as the electrons' interactions become increasingly important relative to their kinetic energy: the resistivity undergoes a transition from metallic to insulating temperature dependence; the resistance increases sharply and then saturates abruptly with increasing in-plane magnetic field; a number of experiments indicate that the electrons' effective mass exhibits a substantial increase approaching a finite ``critical'' density. There has been a great deal of debate concerning the underlying physics in these systems, and many have questioned whether the change of the resistivity from metallic to insulating signals a phase transition or a crossover. In this talk, I will report measurements that show that with decreasing density ns, the thermopower S of a low-disorder 2D electron system in silicon exhibits a sharp increase by more than an order of magnitude, tending to a divergence at a finite, disorder-independent density nt, consistent with the critical form (- T / S) ~(ns -nt) x with x = 1 . 0 +/- 0 . 1 (T is the temperature). Unlike the resistivity which may not clearly distinguish between a transition and crossover behavior, the thermopower provides clear evidence that a true phase transition occurs with decreasing density to a new low-density phase. Work supported by DOE Grant DE-FG02-84ER45153, BSF grant 2006375, RFBR, RAS, and the Russian Ministry of Science.
Modeling turbulence structure. Chemical kinetics interaction in turbulent reactive flows
Energy Technology Data Exchange (ETDEWEB)
Magnussen, B.F. [The Norwegian Univ. of Science and Technology, Trondheim (Norway)
1997-12-31
The challenge of the mathematical modelling is to transfer basic physical knowledge into a mathematical formulation such that this knowledge can be utilized in computational simulation of practical problems. The combustion phenomena can be subdivided into a large set of interconnected phenomena like flow, turbulence, thermodynamics, chemical kinetics, radiation, extinction, ignition etc. Combustion in one application differs from combustion in another area by the relative importance of the various phenomena. The difference in fuel, geometry and operational conditions often causes the differences. The computer offers the opportunity to treat the individual phenomena and their interactions by models with wide operational domains. The relative magnitude of the various phenomena therefore becomes the consequence of operational conditions and geometry and need not to be specified on the basis of experience for the given problem. In mathematical modelling of turbulent combustion, one of the big challenges is how to treat the interaction between the chemical reactions and the fluid flow i.e. the turbulence. Different scientists adhere to different concepts like the laminar flamelet approach, the pdf approach of the Eddy Dissipation Concept. Each of these approaches offers different opportunities and problems. All these models are based on a sound physical basis, however none of these have general validity in taking into consideration all detail of the physical chemical interaction. The merits of the models can only be judged by their ability to reproduce physical reality and consequences of operational and geometric conditions in a combustion system. The presentation demonstrates and discusses the development of a coherent combustion technology for energy conversion and safety based on the Eddy Dissipation Concept by Magnussen. (author) 30 refs.
International Nuclear Information System (INIS)
Khan, S. Sudheer; Srivatsan, P.; Vaishnavi, N.; Mukherjee, Amitava; Chandrasekaran, N.
2011-01-01
Highlights: → Bacterial extracellular proteins stabilize the silver nanoparticles. → Adsorption process varies with pH and salt concentration of the interaction medium. → Adsorption process was strongly influenced by surface charge. → Adsorption equilibrium isotherms was fitted well by the Freundlich model. → Kinetics of adsorption was fitted by pseudo-second-order. -- Abstract: Indiscriminate and increased use of silver nanoparticles (SNPs) in consumer products leads to the release of it into the environment. The fate and transport of SNPs in environment remains unknown. We have studied the interaction of SNPs with extracellular protein (ECP) produced by two environmental bacterial species and the adsorption behavior in aqueous solutions. The effect of pH and salt concentrations on the adsorption was also investigated. The adsorption process was found to be dependent on surface charge (zeta potential). The capping of SNPs by ECP was confirmed by Fourier transform infrared spectroscopy and X-ray diffraction. The adsorption of ECP on SNPs was analyzed by Langmuir and Freundlich models, suggesting that the equilibrium adsorption data fitted well with Freundlich model. The equilibrium adsorption data were modeled using the pseudo-first-order and pseudo-second-order kinetic equations. The results indicated that pseudo-second-order kinetic equation would better describe the adsorption kinetics. The capping was stable at environmental pH and salt concentration. The destabilization of nanoparticles was observed at alkaline pH. The study suggests that the stabilization of nanoparticles in the environment might lead to the accumulation and transport of nanomaterials in the environment, and ultimately destabilizes the functioning of the ecosystem.
Quantum magnetism in strongly interacting one-dimensional spinor Bose systems
DEFF Research Database (Denmark)
Salami Dehkharghani, Amin; Volosniev, A. G.; Lindgren, E. J.
2015-01-01
-range inter-species interactions much larger than their intra-species interactions and show that they have novel energetic and magnetic properties. In the strongly interacting regime, these systems have energies that are fractions of the basic harmonic oscillator trap quantum and have spatially separated...
Qianqian Wang; Xuebing Zhao; J.Y. Zhu
2014-01-01
Cellulose nanocrytals (CNCs) are predominantly produced using the traditional strong acid hydrolysis process. In most reported studies, the typical CNC yield is low (approximately 30%) despite process optimization. This study investigated the hydrolysis of a bleached kraft eucalyptus pulp using sulfuric acid between 50 and 64 wt % at temperatures of 35−80 Â°C...
Static and kinetic friction of strongly confined polymer films under shear
Hirz, S; Subbotin, A; Frank, C; Hadziioannou, G
1996-01-01
In the present work, we investigate the dependence of relaxational processes in strongly confined polymer liquids as a function of the molecular mass and of the confining film thickness, both theoretically and experimentally. A qualitative agreement is observed between the theoretical predictions
Directory of Open Access Journals (Sweden)
Hanna Björkelund
Full Text Available The interaction of the epidermal growth factor (EGF with its receptor (EGFR is known to be complex, and the common over-expression of EGF receptor family members in a multitude of tumors makes it important to decipher this interaction and the following signaling pathways. We have investigated the affinity and kinetics of (125I-EGF binding to EGFR in four human tumor cell lines, each using four culturing conditions, in real time by use of LigandTracer®.Highly repeatable and precise measurements show that the overall apparent affinity of the (125I-EGF - EGFR interaction is greatly dependent on cell line at normal culturing conditions, ranging from K(D ≈ 200 pM on SKBR3 cells to K(D≈8 nM on A431 cells. The (125I-EGF - EGFR binding curves (irrespective of cell line have strong signs of multiple simultaneous interactions. Furthermore, for the cell lines A431 and SKOV3, gefitinib treatment increases the (125I-EGF - EGFR affinity, in particular when the cells are starved. The (125I-EGF - EGFR interaction on cell line U343 is sensitive to starvation while as on SKBR3 it is insensitive to gefitinib and starvation.The intriguing pattern of the binding characteristics proves that the cellular context is important when deciphering how EGF interacts with EGFR. From a general perspective, care is advisable when generalizing ligand-receptor interaction results across multiple cell-lines.
Energy Technology Data Exchange (ETDEWEB)
Abadli, S. [Department of Electrical Engineering, University Aout 1955, Skikda, 21000 (Algeria); LEMEAMED, Department of Electronics, University Mentouri, Constantine, 25000 (Algeria); Mansour, F. [LEMEAMED, Department of Electronics, University Mentouri, Constantine, 25000 (Algeria); Pereira, E. Bedel [CNRS-LAAS, 7 avenue du colonel Roche, 31077 Toulouse (France)
2012-10-15
We have investigated the complex behaviour of boron (B) redistribution process via silicon thin bi-layers interface. It concerns the instantaneous kinetics of B transfer, trapping, clustering and segregation during the thermal B activation annealing. The used silicon bi-layers have been obtained by low pressure chemical vapor deposition (LPCVD) method at 480 C, by using in-situ nitrogen-doped-silicon (NiDoS) layer and strongly B doped polycrystalline-silicon (P{sup +}) layer. To avoid long-range B redistributions, thermal annealing was carried out at relatively low-temperatures (600 C and 700 C) for various times ranging between 30 min and 2 h. To investigate the experimental secondary ion mass spectroscopy (SIMS) doping profiles, a redistribution model well adapted to the particular structure of two thin layers and to the effects of strong-concentrations has been established. The good adjustment of the simulated profiles with the experimental SIMS profiles allowed a fundamental understanding about the instantaneous physical phenomena giving and disturbing the complex B redistribution profiles-shoulders. The increasing kinetics of the B peak concentration near the bi-layers interface is well reproduced by the established model. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Advances in the Application of the Similarity Renormalization Group to Strongly Interacting Systems
Wendt, Kyle Andrew
The Similarity Renormalization Group (SRG) as applied in nuclear physics is a tool to soften and decouple inter-nucleon interactions. The necessity for such a tool is generated by the strong coupling of high- and low-momentum degrees of freedom in modern precision interactions. In recent years the SRG have been used with great success in enhancing few (2-12) nucleon calculations, but there are still many open questions about the nature of the SRG, and how it affects chiral forces. This thesis focuses on three topics within the study of the SRG as it applies to nuclear few-body interactions, with a focus on nuclear forces from chiral effective field theory. The typical SRG applied to nuclear physics is the T̂ rel-SRG, which uses the relative kinetic energy to generate a renormalizing flow. However, this generator explicitly violates criteria that ensure the SRG will decouple the interaction. Previous study of this generator found for a simple model that as the resolution is lowered past the momentum scales associated with a bound state, the T̂rel-SRG enhances coupling near the bound state whereas the classical Wegner generator completely decouples the bound state. In practice, this has not been an issue because the only two-body bound state is very shallow, and therefore well below the SRG softening scales. This study is extended to use leading order chiral effective field theory with large cutoffs to explore this decoupling. This builds in the same low energy physics while including spurious high energy details, including high energy bound states. The evolutions with T̂rel-SRG are compared to the evolution with Wegner's generator. During the decoupling process, the SRG can induce new non-local contributions to the interactions, which inhibits its application using Quantum Monte Carlo (QMC) methods. Separating out the non-local terms is numerically difficult. Instead an approximate separation is applied to T̂ rel-SRG evolved interactions and the nature of the
Directory of Open Access Journals (Sweden)
Yuan J
2014-07-01
Full Text Available Jing Yuan, Yanan Gao, Xinyu Wang, Hongzhuo Liu, Xin Che, Lu Xu, Yang Yang, Qifang Wang, Yan Wang, Sanming LiSchool of Pharmacy, Shenyang Pharmaceutical University, Shenyang, People’s Republic of China Abstract: Ion-exchange fibers were different from conventional ion-exchange resins in their non-cross-linked structure. The exchange was located on the surface of the framework, and the transport resistance reduced significantly, which might mean that the exchange is controlled by an ionic reaction instead of diffusion. Therefore, this work aimed to investigate the load and release characteristics of five model drugs with the strong cationic ion-exchange fiber ZB-1. Drugs were loaded using a batch process and released in United States Pharmacopoeia (USP dissolution apparatus 2. Opposing exchange kinetics, suitable for the special structure of the fiber, were developed for describing the exchange process with the help of thermodynamics, which illustrated that the load was controlled by an ionic reaction. The molecular weight was the most important factor to influence the drug load and release rate. Strong alkalinity and rings in the molecular structures made the affinity between the drug and fiber strong, while logP did not cause any profound differences. The drug–fiber complexes exhibited sustained release. Different kinds and concentrations of counter ions or different amounts of drug–fiber complexes in the release medium affected the release behavior, while the pH value was independent of it. The groundwork for in-depth exploration and further application of ion-exchange fibers has been laid. Keywords: ion-exchange fibers, ionic reaction, drug load and release, opposing exchange kinetics, thermodynamics, influences
Effects of interaction imbalance in a strongly repulsive one-dimensional Bose gas
DEFF Research Database (Denmark)
Barfknecht, Rafael Emilio; Zinner, Nikolaj Thomas; Foerster, Angela
2018-01-01
We calculate the spatial distributions and the dynamics of a few-body two-component strongly interacting Bose gas confined to an effectively one-dimensional trapping potential. We describe the densities for each component in the trap for different interaction and population imbalances. We calculate...
Effects of interaction imbalance in a strongly repulsive one-dimensional Bose gas
DEFF Research Database (Denmark)
Barfknecht, Rafael Emilio; Zinner, Nikolaj Thomas; Foerster, Angela
2018-01-01
We calculate the spatial distributions and the dynamics of a few-body two-component strongly interacting Bose gas confined to an effectively one-dimensional trapping potential. We describe the densities for each component in the trap for different interaction and population imbalances. We calcula...
Directory of Open Access Journals (Sweden)
Neng-Zhong Xie
Full Text Available Three strong interactions between amino acid side chains (salt bridge, cation-π, and amide bridge are studied that are stronger than (or comparable to the common hydrogen bond interactions, and play important roles in protein-protein interactions.Quantum chemical methods MP2 and CCSD(T are used in calculations of interaction energies and structural optimizations.The energies of three types of amino acid side chain interactions in gaseous phase and in aqueous solutions are calculated using high level quantum chemical methods and basis sets. Typical examples of amino acid salt bridge, cation-π, and amide bridge interactions are analyzed, including the inhibitor design targeting neuraminidase (NA enzyme of influenza A virus, and the ligand binding interactions in the HCV p7 ion channel. The inhibition mechanism of the M2 proton channel in the influenza A virus is analyzed based on strong amino acid interactions.(1 The salt bridge interactions between acidic amino acids (Glu- and Asp- and alkaline amino acids (Arg+, Lys+ and His+ are the strongest residue-residue interactions. However, this type of interaction may be weakened by solvation effects and broken by lower pH conditions. (2 The cation- interactions between protonated amino acids (Arg+, Lys+ and His+ and aromatic amino acids (Phe, Tyr, Trp and His are 2.5 to 5-fold stronger than common hydrogen bond interactions and are less affected by the solvation environment. (3 The amide bridge interactions between the two amide-containing amino acids (Asn and Gln are three times stronger than hydrogen bond interactions, which are less influenced by the pH of the solution. (4 Ten of the twenty natural amino acids are involved in salt bridge, or cation-, or amide bridge interactions that often play important roles in protein-protein, protein-peptide, protein-ligand, and protein-DNA interactions.
Gauge unification of basic forces particularly of gravitation with strong interactions
International Nuclear Information System (INIS)
Salam, A.
1977-01-01
Corresponding to the two known types of gauge theories, Yang-Mills with spin-one mediating particles and Einstein Weyl with spin-two mediating particles, it is speculated that two distinct gauge unifications of the basic forces appear to be taking place. One is the familiar Yang-Mills unification of weak and electromagnetic forces with the strong. The second is the less familiar gauge unification of gravitation with spin-two tensor-dominated aspects of strong interactions. It is proposed that there are strongly interacting spin-two strong gravitons obeying Einstein's equations, and their existence gives a clue to an understanding of the (partial) confinement of quarks, as well as of the concept of hadronic temperature, through the use of Schwarzschild de-Sitter-like partially confining solitonic solutions of the strong gravity Einstein equation
arXiv Recent results from the strong interactions program of NA61/SHINE
Pulawski, Szymon
2017-01-01
The NA61/SHINE experiment studies hadron production in hadron+hadron, hadron+nucleus and nucleus+nucleus collisions. The strong interactions program has two main purposes: study the properties of the onset of deconfinement and search for the signatures of the critical point of strongly interacting matter. This aim is pursued by performing a two-dimensional scan of the phase diagram by varying the energy/momentum (13A-158A GeV/c) and the system size (p+p, Be+Be, Ar+Sc, Xe+La) of the collisions. This publication reviews recent results from p+p, Be+Be and Ar+Sc interactions. Measured particle spectra are discussed and compared to NA49 results from Pb+Pb collisions. The results illustrate the progress towards scanning the phase diagram of strongly interacting matter.
Strong excitonic interactions in the oxygen K-edge of perovskite oxides
Energy Technology Data Exchange (ETDEWEB)
Tomita, Kota; Miyata, Tomohiro [Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro, Tokyo 153-8505 (Japan); Olovsson, Weine [Department of Physics, Chemistry and Biology (IFM), Linköping University, SE-581 83 Linköping (Sweden); Mizoguchi, Teruyasu, E-mail: teru@iis.u-tokyo.ac.jp [Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro, Tokyo 153-8505 (Japan)
2017-07-15
Excitonic interactions of the oxygen K-edge electron energy-loss near-edge structure (ELNES) of perovskite oxides, CaTiO{sub 3}, SrTiO{sub 3}, and BaTiO{sub 3}, together with reference oxides, MgO, CaO, SrO, BaO, and TiO{sub 2}, were investigated using a first-principles Bethe–Salpeter equation calculation. Although the transition energy of oxygen K-edge is high, strong excitonic interactions were present in the oxygen K-edge ELNES of the perovskite oxides, whereas the excitonic interactions were negligible in the oxygen K-edge ELNES of the reference compounds. Detailed investigation of the electronic structure suggests that the strong excitonic interaction in the oxygen K-edge ELNES of the perovskite oxides is caused by the directionally confined, low-dimensional electronic structure at the Ti–O–Ti bonds. - Highlights: • Excitonic interaction in oxygen-K edge is investigated. • Strong excitonic interaction is found in the oxygen-K edge of perovskite oxides. • The strong excitonic interaction is ascribed to the low-dimensional and confined electronic structure.
Lau, Newman M. L.; Chu, Veni H. T.
2015-01-01
This research aimed at investigating the method of using kinetic typography and interactive approach to conduct a design experiment for children to learn vocabularies. Typography is the unique art and technique of arranging type in order to make language visible. By adding animated movement to characters, kinetic typography expresses language…
Kamat, Vishal; Rafique, Ashique
2017-08-01
The surface plasmon resonance (SPR) biosensors are being routinely used in different stages of drug discovery and development. However, the lack of high throughput SPR biosensors continues to be a primary bottleneck for the rapid kinetic screening of large panels of monoclonal antibodies (mAbs). To further increase the throughput of the Biacore 4000 biosensor, we have developed three kinetic screening assays to characterize mAb-antigen interactions - (i) 16-mAb capture kinetic, (ii) single cycle kinetic (SCK), and (iii) parallel kinetic (PK). The performance of all three kinetic assays was evaluated by characterizing the binding of kinetically diverse human mAbs to four antigens with molecular weights of 14kD, 29kD, 38kD, and 48kD and binding affinities ranging from 130pM to 200 nM. The binding rate constants measured using all three kinetic assays were reproducible across multiple experiments and correlated with the values generated using the conventional 8-mAb capture kinetic assay on the Biacore 4000 (R 2 > 0.94). Moreover, the 16-mAb capture assay decreased experiment time and analyte consumption by 35% and 50%, respectively. This work illustrates the significance of the 16-mAb capture kinetic, SCK, and PK assays to increase the throughput of Biacore 4000 and to support rapid kinetic screening of mAbs. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.
Multiscale GasKinetics/Particle (MGP) Simulation for Rocket Plume/Lunar Dust Interactions, Phase I
National Aeronautics and Space Administration — A Multiscale GasKinetic/Particle (MGP) computational method is proposed to simulate the plume-crater-interaction/dust-impingement(PCIDI) problem. The MGP method...
Spectral asymptotics of a strong δ′ interaction supported by a surface
International Nuclear Information System (INIS)
Exner, Pavel; Jex, Michal
2014-01-01
Highlights: • Attractive δ ′ interactions supported by a smooth surface are considered. • Surfaces can be either infinite and asymptotically planar, or compact and closed. • Spectral asymptotics is determined by the geometry of the interaction support. - Abstract: We derive asymptotic expansion for the spectrum of Hamiltonians with a strong attractive δ ′ interaction supported by a smooth surface in R 3 , either infinite and asymptotically planar, or compact and closed. Its second term is found to be determined by a Schrödinger type operator with an effective potential expressed in terms of the interaction support curvatures
Precision determination of the strong interaction shift and width in pionic hydrogen
International Nuclear Information System (INIS)
Anagnostopoulos, D.F.; Covita, D.D.S.; Santos, J.M.F. dos; Veloso, J.F.C.A.; Fuhrmann, H.; Gruber, A.; Hirtl, A.; Ishiwatari, T.; Marton, J.; Schmid, P.; Zmeskal, J.; Gotta, D.; Hennebach, M.; Nekipelov, M.; Indelicato, P.; Jensen, T.; Bigot, E.O. Le; Trassinelli, M.; Simons, L.M.
2005-01-01
The new pionic hydrogen experiment at PSI aims at an improvement in the determination of the strong interaction ground state shift and width of the pionic hydrogen atom. High precision x-ray crystal spectroscopy is used to extract isospin separated scattering lengths with accuracies on the percent level. Compared to previous efforts, the energy resolution and statistics could be improved considerably and the background is much reduced. The response function of the Johann-type crystal spectrometer has been determined with a novel method with unprecedented accuracy. The inherent difficulties of the exotic atom's method result, from the fact that the formation of a sufficient amount of pionic hydrogen atoms requires a hydrogen target pressure of several bar at least. For the extraction of a strong interaction shift, an extrapolation method to vacuum conditions proved to be successful. This contribution mostly discusses the strategy to extract a result for the strong interaction width from the data.(author)
International Nuclear Information System (INIS)
Chan, J.; DePorcel, L.; Dixon, L.
1997-06-01
This conference explored the role of the strong interaction in the physics of hadrons and partons. The Institute attracted 239 physicists from 16 countries to hear lectures on the underlying theory of Quantum Chromodynamics, modern theoretical calculational techniques, and experimental investigation of the strong interaction as it appears in various phenomena. Different regimes in which one can calculate reliably in QCD were addressed in series of lectures on perturbation theory, lattice gauge theories, and heavy quark expansions. Studies of QCD in hadron-hadron collisions, electron-positron annihilation, and electron-proton collisions all give differing perspectives on the strong interaction--from low-x to high-Q 2 . Experimental understanding of the production and decay of heavy quarks as well as the lighter meson states has continued to evolve over the past years, and these topics were also covered at the School. Selected papers have been indexed separately for inclusion in the Energy Science and Technology Database
Computational strong-field quantum dynamics intense light-matter interactions
2017-01-01
This graduate textbook introduces the computational techniques to study ultra-fast quantum dynamics of matter exposed to strong laser fields. Coverage includes methods to propagate wavefunctions according to the time-dependent Schrödinger, Klein-Gordon or Dirac equation, the calculation of typical observables, time-dependent density functional theory, multi-configurational time-dependent Hartree-Fock, time-dependent configuration interaction singles, the strong-field approximation, and the microscopic particle-in-cell approach.
Computational strong-field quantum dynamics. Intense light-matter interactions
Energy Technology Data Exchange (ETDEWEB)
Bauer, Dieter (ed.) [Rostock Univ. (Germany). Inst. fuer Physik
2017-09-01
This graduate textbook introduces the computational techniques to study ultra-fast quantum dynamics of matter exposed to strong laser fields. Coverage includes methods to propagate wavefunctions according to the time dependent Schroedinger, Klein-Gordon or Dirac equation, the calculation of typical observables, time-dependent density functional theory, multi configurational time-dependent Hartree-Fock, time-dependent configuration interaction singles, the strong-field approximation, and the microscopic particle-in-cell approach.
International Nuclear Information System (INIS)
Drechsler, W.
1977-01-01
A Lagrangian formalism invariant under the gauge group U 1 xUSpsub(2.2) is set up in terms of spinor fields defined on a fiber bundle with Cartan connexion. The fiber of the Cartan bundle over space-time associated with strong interactions is characterized by an elementary length parameter R related to the range of the strong forces, and the structural group USpsub(2.2) of the bundle (being the covering group of the SOsub(4.1) de Sitter group) implies a gauge description of strong interactions based on the noncompact gauge group USpsub(2.2). The U 1 factor in the total gauge group corresponds to the usual gauge formulation for the electromagnetic interactions. The positivity of the energy associated with stable extended one-particle states in this dualistic description of charged hadronic matter immersed in the fiber geometry (this dualism is called strong fiber dynamics (SFD)) requires hadrons to be assigned to representations of the compact subgroup SU 2 xSU 2 of the strong-interaction gauge group USpsub(2.2). A brief discussion of the point-particle limit R→O is given by linking the presented SFD formalism for extended hadrons to an idealized description in terms of operators in a local quantum field theory
Proceedings of Summer Institute of Particle Physics, July 27-August 7, 1981: the strong interactions
Energy Technology Data Exchange (ETDEWEB)
Mosher, A. (ed.)
1982-01-01
The ninth SLAC Summer Institute on Particle Physics was held in the period July 27 to August 7, 1981. The central topic was the strong interactions with the first seven days spent in a pedagogic mode and the last three in a topical conference. In addition to the morning lectures on experimental and theoretical aspects of the strong interactions, three were lectures on machine physics; this year it was electron-positron colliding beam machines, both storage rings and linear colliders. Twenty-three individual items from the meeting were prepared separately for the data base. (GHT)
Strong interaction effects in high-Z K sup minus atoms
Energy Technology Data Exchange (ETDEWEB)
Batty, C.J.; Eckhause, M.; Gall, K.P.; Guss, P.P.; Hertzog, D.W.; Kane, J.R.; Kunselman, A.R.; Miller, J.P.; O' Brien, F.; Phillips, W.C.; Powers, R.J.; Roberts, B.L.; Sutton, R.B.; Vulcan, W.F.; Welsh, R.E.; Whyley, R.J.; Winter, R.G. (Rutherford-Appleton Laboratory, Chilton, Didcot OX11 0QX, United Kingdom (GB) College of William and Mary, Williamsburg, Virginia 23185 Boston University, Boston, Massachusetts 02215 University of Wyoming, Laramie, Wyoming 82071 California Institute of Technology, Pasadena, California 91125 Carnegie-Mellon University, Pittsburgh, Pennsylvania 15213)
1989-11-01
A systematic experimental study of strong interaction shifts, widths, and yields from high-{ital Z} kaonic atoms is reported. Strong interaction effects for the {ital K}{sup {minus}}(8{r arrow}7) transition were measured in U, Pb, and W, and the {ital K}{sup {minus}}(7{r arrow}6) transition in W was also observed. This is the first observation of two measurably broadened and shifted kaonic transitions in a single target and thus permitted the width of the upper state to be determined directly, rather than being inferred from yield data. The results are compared with optical-model calculations.
Marri, Ivan; Govoni, Marco; Ossicini, Stefano
2014-09-24
We present density functional theory calculations of carrier multiplication properties in a system of strongly coupled silicon nanocrystals. Our results suggest that nanocrystal-nanocrystal interaction can lead to a reduction of the carrier multiplication energy threshold without altering the carrier multiplication efficiency at high energies, in agreement with experiments. The time evolution of the number of electron-hole pairs generated in a system of strongly interacting nanocrystals upon absorption of high-energy photons is analyzed by solving a system of coupled rate equations, where exciton recycling mechanisms are implemented. We reconsider the role played by Auger recombination which is here accounted also as an active, nondetrimental process.
Relaxation of strongly coupled Coulomb systems after rapid changes of the interaction potential
Gericke, D O; Semkat, D; Bonitz, M; Kremp, D
2003-01-01
The relaxation of charged particle systems after sudden changes of the pair interaction strength is investigated. As examples, we show the results for plasmas after ionization and after a rapid change of screening. Comparisons are made between molecular dynamics simulation and a kinetic description based on the Kadanoff-Baym equations. We found the latter very sensitive to the way the scattering cross section is treated. We also predict the new equilibrium state requiring only conservation of energy. In this case, the correlation energy is computed using the hypernetted chain approximation.
Engineering the Dynamics of Effective Spin-Chain Models for Strongly Interacting Atomic Gases
DEFF Research Database (Denmark)
Volosniev, A. G.; Petrosyan, D.; Valiente, M.
2015-01-01
We consider a one-dimensional gas of cold atoms with strong contact interactions and construct an effective spin-chain Hamiltonian for a two-component system. The resulting Heisenberg spin model can be engineered by manipulating the shape of the external confining potential of the atomic gas. We...
Density functional theory for strongly-interacting electrons: Perspectives for Physics and Chemistry
Gori Giorgi, P.; Seidl, M.
2010-01-01
Improving the accuracy and thus broadening the applicability of electronic density functional theory (DFT) is crucial to many research areas, from material science, to theoretical chemistry, biophysics and biochemistry. In the last three years, the mathematical structure of the strong-interaction
Czech Academy of Sciences Publication Activity Database
Exner, Pavel; Pankrashkin, K.
2014-01-01
Roč. 39, č. 2 (2014), s. 193-212 ISSN 0360-5302 R&D Projects: GA ČR GAP203/11/0701 Institutional support: RVO:61389005 Keywords : Eigenvalue * Schrödinger operator * singular interaction * strong coupling * 35Q40 * 35P15 * 35J10 Subject RIV: BE - Theoretical Physics Impact factor: 1.013, year: 2014
Spectral asymptotics of a strong delta ' interaction supported by a surface
Czech Academy of Sciences Publication Activity Database
Exner, Pavel; Jex, M.
2014-01-01
Roč. 378, 30-31 (2014), s. 2091-2095 ISSN 0375-9601 R&D Projects: GA ČR(CZ) GA14-06818S Institutional support: RVO:61389005 Keywords : delta ' surface interaction * strong coupling expansion Subject RIV: BE - Theoretical Physics Impact factor: 1.683, year: 2014
On eigenvalue asymptotics for strong delta-interactions supported by surfaces with boundaries
Czech Academy of Sciences Publication Activity Database
Dittrich, Jaroslav; Exner, Pavel; Kuhn, C.; Pankrashkin, K.
2016-01-01
Roč. 97, 1-2 (2016), s. 1-25 ISSN 0921-7134 R&D Projects: GA ČR(CZ) GA14-06818S Institutional support: RVO:61389005 Keywords : singular Schrodinger operator * delta-interaction * strong coupling * eigenvalue Subject RIV: BE - Theoretical Physics Impact factor: 0.933, year: 2016
Fractional energy states of strongly-interacting bosons in one dimension
DEFF Research Database (Denmark)
Zinner, Nikolaj Thomas; G. Volosniev, A.; V. Fedorov, D.
2014-01-01
We study two-component bosonic systems with strong inter-species and vanishing intra-species interactions. A new class of exact eigenstates is found with energies that are {\\it not} sums of the single-particle energies with wave functions that have the characteristic feature that they vanish over...
Flavor changing strong interaction effects on top quark physics at the CERN LHC
International Nuclear Information System (INIS)
Ferreira, P.M.; Santos, R.; Oliveira, O.
2006-01-01
We perform a model independent analysis of the flavor changing strong interaction vertices relevant to the LHC. In particular, the contribution of dimension six operators to single top production in various production processes is discussed, together with possible hints for identifying signals and setting bounds on physics beyond the standard model
Interaction of a neutral composite particle with a strong Coulomb field
International Nuclear Information System (INIS)
Wong, Cheuk-Yin.
1988-01-01
The author discusses the interaction of the quasi-composite (e/sup /plus//e/sup /minus//) system with an external electromagnetic field. This problem addresses the question of the origin of strong positron lines in quasi-elastic heavy-ion reactions. 3 refs
Description of meson strong and electromagnetic interactions in quantum chiral theory
International Nuclear Information System (INIS)
Volkov, M.K.; Pervushin, V.N.
1978-01-01
Strong and electromagnetic interactions of mesons in the framework of the chiral theory are considered. The pion-pion scattering phases, the pion electromagnetic form factor, the mean squared radius of a K-meson, and the electric and magnetic polarizabilities of pions are calculated using the superpropagator method. The rho-meson mass, Msub(rho)=800 MeV, is calculated too
Strongly interacting bosons in a one-dimensional optical lattice at incommensurate densities
Lazarides, A.|info:eu-repo/dai/nl/315556668; Tieleman, O.|info:eu-repo/dai/nl/341386456; de Morais Smith, C.|info:eu-repo/dai/nl/304836346
2011-01-01
We investigate quantum phase transitions occurring in a system of strongly interacting ultracold bosons in a one-dimensional optical lattice. After discussing the commensurate-incommensurate transition, we focus on the phases appearing at an incommensurate filling. We find a rich phase diagram, with
DEFF Research Database (Denmark)
Petrosyan, David; Molmer, Klaus
2013-01-01
We study two-photon excitation of Rydberg states of atoms under stimulated adiabatic passage with delayed laser pulses. We find that the combination of strong interaction between the atoms in Rydberg state and the spontaneous decay of the intermediate exited atomic state leads to the Rydberg...
The strong interaction in e+e- annihilation and deep inelastic scattering
International Nuclear Information System (INIS)
Samuelsson, J.
1996-01-01
Various aspects of strong interactions are considered. Correlation effects in the hadronization process in a string model are studied. A discrete approximation scheme to the perturbative QCD cascade in e + e - annihilation is formulated. The model, Discrete QCD, predicts a rather low phase space density of 'effective gluons'. This is related to the properties of the running coupling constant. It provides us with a simple tool for studies of the strong interaction. It is shown that it reproduces well-known properties of parton cascades. A new formalism for the Deep Inelastic Scattering (DIS) process is developed. The model which is called the Linked Dipole Chain Model provides an interpolation between regions of high Q 2 (DGLAP) and low x-moderate Q 2 (BFKL). It gives a unified treatment of the different interaction channels an a DIS process. 17 figs
Strongly interacting dark matter: Self-interactions and keV lines
Boddy, Kimberly K.; Feng, Jonathan L.; Kaplinghat, Manoj; Shadmi, Yael; Tait, Timothy M. P.
2014-11-01
We consider a simple supersymmetric hidden sector: pure SU (N ) gauge theory. Dark matter is made up of hidden glueballinos with mass mX and hidden glueballs with mass near the confinement scale Λ . For mX˜1 TeV and Λ ˜100 MeV , the glueballinos freeze out with the correct relic density and self-interact through glueball exchange to resolve small-scale structure puzzles. An immediate consequence is that the glueballino spectrum has a hyperfine splitting of order Λ2/mX˜10 keV . We show that the radiative decays of the excited state can explain the observed 3.5 keV x-ray line signal from clusters of galaxies, Andromeda, and the Milky Way.
Interaction between "dissipative solitons" stabilized by aggregation in excitable kinetics
Mangioni, Sergio E.
2014-10-01
We consider that a population of individuals governed by the Nagumo model is characterized by predisposition towards aggregation. "Dissipative solitons" interacting are solutions for such system. We changed the possibility of extinction, predicted by Nagumo model, by a uniform background of low population's density and then we observed relevant effect on interaction between "solitons".
Heavy quark mass effects and improved tests of the flavor independence of strong interactions
Energy Technology Data Exchange (ETDEWEB)
Burrows, P.N. [Univ. of Oxford (United Kingdom); SLD Collaboration
1998-08-01
A review is given of latest results on tests of the flavor independence of strong interactions. Heavy quark mass effects are evident in the data and are now taken into account at next-to-leading order in QCD perturbation theory. The strong-coupling ratios {alpha}{sub s}{sup b}/{alpha}{sub s}{sup uds} and {alpha}{sub s}{sup c}/{alpha}{sub s}{sup uds} are found to be consistent with unity. Determinations of the b-quark mass m{sub b} (M{sub Z}) are discussed.
Strong field approximation within a Faddeev-like formalism for laser-matter interactions
International Nuclear Information System (INIS)
Popov, Y.; Galstyan, A.; Piraux, B.; Mota-Furtado, F.; O'Mahony, P.F.
2017-01-01
We consider the interaction of atomic hydrogen with an intense laser field within the strong-field approximation (SFA). By using a Faddeev-like formalism, we introduce a new perturbative series in the binding potential of the atom. As a first test of this new approach, we calculate the electron energy spectrum in the very simple case of a photon energy higher than the ionisation potential. We show that by contrast to the standard perturbative series in the binding potential obtained within the strong field approximation, the first terms of the new series converge rapidly towards the results we get by solving the corresponding time-dependent Schroedinger equation. (authors)
Yokoyama, Tomohiro; Eto, Mikio; Nazarov, Yuli
2014-03-01
We theoretically investigate the Josephson junction using quasi-one dimensional semiconductor nanowires with strong spin-orbit (SO) interaction, e.g., InSb. First, we examine a simple model using a single scatterer to describe the elastic scattering due to impurities and SO interaction in the normal region.[1] The Zeeman effect is taken into account by the spin-dependent phase shift of electron and hole through the system. The interplay between SO interaction and Zeeman effect results in a finite supercurrent even when the phase difference between two superconductors is zero. Moreover, the critical current depends on its current direction if more than one conduction channel is present in the nanowire. Next, we perform a numerical simulation by the tight-binding model for the nanowire to confirm our simple model. Then, we show that a spin-dependent Fermi velocity due to the SO interaction causes the anomalous Josephson effect.
International Nuclear Information System (INIS)
Sivan, N.; Levit, S.
1992-01-01
We present a semiclassical theory of charged interacting anyons in a strong magnetic field. We derive the appropriate generalization of the WKB quantization conditions and determine the corresponding wave functions for non separable integrable anyonic systems. This theory is applies to a system of two interacting anyons, two interacting anyons in the presence of an impurity and three interacting anyons. We calculate the dependence of the semiclassical energy levels on the statistical parameter and find regions in which dependence follows very different patterns. The semiclassical treatment allows to find the correlation between these patterns and the change in the character of the classical motion of the system. We also test the accuracy of the mean field approximation for low and high energy states of the three anyons. (author)
International Nuclear Information System (INIS)
Arnold, R.C.
1975-12-01
A systematic calculus of long-range Regge cut effects in multiparticle production is constructed in the form of an infrared-divergent stochastic field theory. Total cross sections and two-body overlap integrals in such a theory may depend very sensitively upon internal quantum-numbers of incident particles, resulting in a strong symmetry breaking at ultra-high energies. Such symmetry violations will influence low energy processes through dispersion relations, and a bootstrap of weak interactions becomes possible. A rough analytic estimate of the scale of thresholds for such effects yields a BCS-type gap equation, which expresses the scale of weak and electromagnetic couplings in terms of purely strong-interaction parameters
Bogolubov–Hartree–Fock Theory for Strongly Interacting Fermions in the Low Density Limit
Energy Technology Data Exchange (ETDEWEB)
Bräunlich, Gerhard [Friedrich-Schiller-University Jena, Institute for Mathematics (Germany); Hainzl, Christian [University of Tübingen, Mathematical Institute (Germany); Seiringer, Robert, E-mail: robert.seiringer@ist.ac.at [Institute of Science and Technology Austria (Austria)
2016-06-15
We consider the Bogolubov–Hartree–Fock functional for a fermionic many-body system with two-body interactions. For suitable interaction potentials that have a strong enough attractive tail in order to allow for two-body bound states, but are otherwise sufficiently repulsive to guarantee stability of the system, we show that in the low-density limit the ground state of this model consists of a Bose–Einstein condensate of fermion pairs. The latter can be described by means of the Gross–Pitaevskii energy functional.
Strong constraints on self-interacting dark matter with light mediators
International Nuclear Information System (INIS)
Bringmann, Torsten; Walia, Parampreet
2017-04-01
Coupling dark matter to light new particles is an attractive way to combine thermal production with strong velocity-dependent self-interactions. Here we point out that in such models the dark matter annihilation rate is generically enhanced by the Sommerfeld effect, and we derive the resulting constraints from the Cosmic Microwave Background and other indirect detection probes. For the frequently studied case of s-wave annihilation these constraints exclude the entire parameter space where the self-interactions are large enough to address the small-scale problems of structure formation.
Strong enhancement of light-matter interaction in graphene coupled to a photonic crystal nanocavity.
Gan, Xuetao; Mak, Kin Fai; Gao, Yuanda; You, Yumeng; Hatami, Fariba; Hone, James; Heinz, Tony F; Englund, Dirk
2012-11-14
We demonstrate a large enhancement in the interaction of light with graphene through coupling with localized modes in a photonic crystal nanocavity. Spectroscopic studies show that a single atomic layer of graphene reduces the cavity reflection by more than a factor of one hundred, while also sharply reducing the cavity quality factor. The strong interaction allows for cavity-enhanced Raman spectroscopy on subwavelength regions of a graphene sample. A coupled-mode theory model matches experimental observations and indicates significantly increased light absorption in the graphene layer. The coupled graphene-cavity system also enables precise measurements of graphene's complex refractive index.
Equilibration Dynamics of Strongly Interacting Bosons in 2D Lattices with Disorder.
Yan, Mi; Hui, Hoi-Yin; Rigol, Marcos; Scarola, V W
2017-08-18
Motivated by recent optical lattice experiments [J.-y. Choi et al., Science 352, 1547 (2016)SCIEAS0036-807510.1126/science.aaf8834], we study the dynamics of strongly interacting bosons in the presence of disorder in two dimensions. We show that Gutzwiller mean-field theory (GMFT) captures the main experimental observations, which are a result of the competition between disorder and interactions. Our findings highlight the difficulty in distinguishing glassy dynamics, which can be captured by GMFT, and many-body localization, which cannot be captured by GMFT, and indicate the need for further experimental studies of this system.
Gauge unification of basic forces, particularly of gravitation with strong interactions
International Nuclear Information System (INIS)
Salam, A.
1977-01-01
An attempt is made to present a case for the use of both the Einstein--Weyl spin-two and the Yang--Mills spin-one gauge structures for describing strong interactions. By emphasizing both spin-one and -two aspects of this force, it is hoped that a unification of this force, on the one hand, with gravity theory and, on the other, with the electromagnetic and weak interactions can be achieved. A Puppi type of tetrahedral interralation of fundamental forces, with the strong force playing a pivotal role due to its mediation through both spin-one and -two quanta, is proposed. It is claimed that the gauge invariance of gravity theory permits the use of ambuguity-free nonpolynomial techniques and thereby the securing of relistic regularization in gravity-modified field theories with the Newtonian constant G/sub N/ providing a relistic cutoff. 37 references
Les Houches Summer School : Strongly Interacting Quantum Systems out of Equilibrium
Millis, Andrew J; Parcollet, Olivier; Saleur, Hubert; Cugliandolo, Leticia F
2016-01-01
Over the last decade new experimental tools and theoretical concepts are providing new insights into collective nonequilibrium behavior of quantum systems. The exquisite control provided by laser trapping and cooling techniques allows us to observe the behavior of condensed bose and degenerate Fermi gases under nonequilibrium drive or after quenches' in which a Hamiltonian parameter is suddenly or slowly changed. On the solid state front, high intensity short-time pulses and fast (femtosecond) probes allow solids to be put into highly excited states and probed before relaxation and dissipation occur. Experimental developments are matched by progress in theoretical techniques ranging from exact solutions of strongly interacting nonequilibrium models to new approaches to nonequilibrium numerics. The summer school Strongly interacting quantum systems out of equilibrium' held at the Les Houches School of Physics as its XCIX session was designed to summarize this progress, lay out the open questions and define dir...
On the Frequency Distribution of Neutral Particles from Low-Energy Strong Interactions
Directory of Open Access Journals (Sweden)
Federico Colecchia
2017-01-01
Full Text Available The rejection of the contamination, or background, from low-energy strong interactions at hadron collider experiments is a topic that has received significant attention in the field of particle physics. This article builds on a particle-level view of collision events, in line with recently proposed subtraction methods. While conventional techniques in the field usually concentrate on probability distributions, our study is, to our knowledge, the first attempt at estimating the frequency distribution of background particles across the kinematic space inside individual collision events. In fact, while the probability distribution can generally be estimated given a model of low-energy strong interactions, the corresponding frequency distribution inside a single event typically deviates from the average and cannot be predicted a priori. We present preliminary results in this direction and establish a connection between our technique and the particle weighting methods that have been the subject of recent investigation at the Large Hadron Collider.
Thermodynamics of strongly interacting fermions in two-dimensional optical lattices
Energy Technology Data Exchange (ETDEWEB)
Khatami, Ehsan; Rigol, Marcos [Department of Physics, Georgetown University, Washington DC, 20057 (United States); Kavli Institute for Theoretical Physics, University of California, Santa Barbara, Santa Barbara, California 93106 (United States)
2011-11-15
We study finite-temperature properties of strongly correlated fermions in two-dimensional optical lattices by means of numerical linked cluster expansions, a computational technique that allows one to obtain exact results in the thermodynamic limit. We focus our analysis on the strongly interacting regime, where the on-site repulsion is of the order of or greater than the band width. We compute the equation of state, double occupancy, entropy, uniform susceptibility, and spin correlations for temperatures that are similar to or below the ones achieved in current optical lattice experiments. We provide a quantitative analysis of adiabatic cooling of trapped fermions in two dimensions, by means of both flattening the trapping potential and increasing the interaction strength.
Limitations due to strong head-on beam-beam interactions (MD 1434)
Buffat, Xavier; Iadarola, Giovanni; Papadopoulou, Parthena Stefania; Papaphilippou, Yannis; Pellegrini, Dario; Pojer, Mirko; Crockford, Guy; Salvachua Ferrando, Belen Maria; Trad, Georges; Barranco Garcia, Javier; Pieloni, Tatiana; Tambasco, Claudia; CERN. Geneva. ATS Department
2017-01-01
The results of an experiment aiming at probing the limitations due to strong head on beam-beam interactions are reported. It is shown that the loss rates significantly increase when moving the working point up and down the diagonal, possibly due to effects of the 10th and/or 14th order resonances. Those limitations are tighter for bunches with larger beam-beam parameters, a maximum total beam-beam tune shift just below 0.02 could be reached.
Model for Thermal Relic Dark Matter of Strongly Interacting Massive Particles.
Hochberg, Yonit; Kuflik, Eric; Murayama, Hitoshi; Volansky, Tomer; Wacker, Jay G
2015-07-10
A recent proposal is that dark matter could be a thermal relic of 3→2 scatterings in a strongly coupled hidden sector. We present explicit classes of strongly coupled gauge theories that admit this behavior. These are QCD-like theories of dynamical chiral symmetry breaking, where the pions play the role of dark matter. The number-changing 3→2 process, which sets the dark matter relic abundance, arises from the Wess-Zumino-Witten term. The theories give an explicit relationship between the 3→2 annihilation rate and the 2→2 self-scattering rate, which alters predictions for structure formation. This is a simple calculable realization of the strongly interacting massive-particle mechanism.
The choice of optimal Discrete Interaction Approximation to the kinetic integral for ocean waves
Directory of Open Access Journals (Sweden)
V. G. Polnikov
2003-01-01
Full Text Available A lot of discrete configurations for the four-wave nonlinear interaction processes have been calculated and tested by the method proposed earlier in the frame of the concept of Fast Discrete Interaction Approximation to the Hasselmann's kinetic integral (Polnikov and Farina, 2002. It was found that there are several simple configurations, which are more efficient than the one proposed originally in Hasselmann et al. (1985. Finally, the optimal multiple Discrete Interaction Approximation (DIA to the kinetic integral for deep-water waves was found. Wave spectrum features have been intercompared for a number of different configurations of DIA, applied to a long-time solution of kinetic equation. On the basis of this intercomparison the better efficiency of the configurations proposed was confirmed. Certain recommendations were given for implementation of new approximations to the wave forecast practice.
arXiv Recent results and future of the NA61/SHINE strong interactions program
Lysakowski, Bartosz
2018-01-01
NA61/SHINE is a fixed target experiment at the CERN Super-Proton- Synchrotron. The main goals of the experiment are to discover the critical point of strongly interacting matter and study the properties of the onset of deconfnement. In order to reach these goals the collaboration studies hadron production properties in nucleus-nucleus, proton-proton and proton-nucleus interactions. In this talk, recent results on particle production in p+p interactions, as well as Be+Be and Ar+Sc collisions in the SPS energy range are reviewed. The results are compared with available world data. The future of the NA61/SHINE scientifc program is also presented.
Strong late-time circumstellar interaction in the peculiar supernova iPTF14hls
Andrews, Jennifer E.; Smith, Nathan
2018-03-01
We present a moderate-resolution spectrum of the peculiar Type II supernova iPTF14hls taken on day 1153 after discovery. This spectrum reveals the clear signature of shock interaction with dense circumstellar material (CSM). We suggest that this CSM interaction may be an important clue for understanding the extremely unusual photometric and spectroscopic evolution seen over the first 600 days of iPTF14hls. The late-time spectrum shows a double-peaked intermediate-width Hα line indicative of expansion speeds around 1000 km s-1, with the double-peaked shape hinting at a disc-like geometry in the CSM. If the CSM was highly asymmetric, perhaps in a disc or torus that was ejected from the star 3-6 years prior to explosion, then the CSM interaction could have been overrun and hidden below the SN ejecta photosphere from a wide range of viewing angles. In that case, CSM interaction luminosity would have been thermalized well below the photosphere, potentially sustaining the high luminosity without exhibiting the traditional observational signatures of strong CSM interaction (narrow Hα emission and X-rays). Variations in density structure of the CSM could account for the multiple rebrightenings of the lightcurve. We propose that a canonical 1× 1051 erg explosion energy with enveloped CSM interaction as seen in some recent SNe, rather than an entirely new explosion mechanism, may be adequate to explain the peculiar evolution of iPTF14hls.
Quantum kinetic exciton-LO-phonon interaction in CdSe
DEFF Research Database (Denmark)
Woggon, Ulrike; Gindele, Frank; Langbein, Wolfgang
2000-01-01
Oscillations with a period of similar to 150 fs are observed in the four-wave mixing (FWM) signal of bulk CdSe and interpreted in terms of non-Markovian exciton-LO-phonon scattering. The experiments show evidence of phonon quantum kinetics in semiconductors of strong polar coupling strength...
Role of high-order dispersion on strong-field laser-molecule interactions
Dantus, Marcos; Nairat, Muath
2016-05-01
Strong-field (1012- 1016 W/ cm2) laser-matter interactions are characterized by the extent of fragmentation and charge of the resulting ions as a function of peak intensity and pulse duration. Interactions are influenced by high-order dispersion, which is difficult to characterize and compress. Fourth-order dispersion (FOD) causes a time-symmetric pedestal, while third-order dispersion (TOD) causes a leading (negative) or following (positive) pedestal. Here, we report on strong-field interactions with pentane and toluene molecules, tracking the molecular ion and the doubly charged carbon ion C2+ yields as a function of TOD and FOD for otherwise transform-limited (TL) 35fs pulses. We find TL pulses enhance molecular ion yield and suppress C2+ yield, while FOD reverses this trend. Interestingly, the leading pedestal in negative TOD enhances C2+ yield compared to positive TOD. Pulse pedestals are of particular importance in strong-field science because target ionization or alignment can be induced well before the main pulse arrives. A pedestal following an intense laser pulse can cause sequential ionization or accelerate electrons causing cascaded ionization. Control of high-order dispersion allows us to provide strong-field measurements that can help address the mechanisms responsible for different product ions in the presence and absence of pedestals. Financial support of this work comes from the Chemical Sciences, Geosciences and Biosciences Division, Office of Basic Energy Sciences, Office of Science, U.S. Department of Energy, DOE SISGR (DE-SC0002325)
Directory of Open Access Journals (Sweden)
Aditi Gupta
2016-03-01
Full Text Available Epistatic interactions between residues determine a protein's adaptability and shape its evolutionary trajectory. When a protein experiences a changed environment, it is under strong selection to find a peak in the new fitness landscape. It has been shown that strong selection increases epistatic interactions as well as the ruggedness of the fitness landscape, but little is known about how the epistatic interactions change under selection in the long-term evolution of a protein. Here we analyze the evolution of epistasis in the protease of the human immunodeficiency virus type 1 (HIV-1 using protease sequences collected for almost a decade from both treated and untreated patients, to understand how epistasis changes and how those changes impact the long-term evolvability of a protein. We use an information-theoretic proxy for epistasis that quantifies the co-variation between sites, and show that positive information is a necessary (but not sufficient condition that detects epistasis in most cases. We analyze the "fossils" of the evolutionary trajectories of the protein contained in the sequence data, and show that epistasis continues to enrich under strong selection, but not for proteins whose environment is unchanged. The increase in epistasis compensates for the information loss due to sequence variability brought about by treatment, and facilitates adaptation in the increasingly rugged fitness landscape of treatment. While epistasis is thought to enhance evolvability via valley-crossing early-on in adaptation, it can hinder adaptation later when the landscape has turned rugged. However, we find no evidence that the HIV-1 protease has reached its potential for evolution after 9 years of adapting to a drug environment that itself is constantly changing. We suggest that the mechanism of encoding new information into pairwise interactions is central to protein evolution not just in HIV-1 protease, but for any protein adapting to a changing
The strong prognostic value of KELIM, a model-based parameter from CA 125 kinetics in ovarian cancer
DEFF Research Database (Denmark)
You, Benoit; Colomban, Olivier; Heywood, Mark
2013-01-01
Unexpected results were recently reported about the poor surrogacy of Gynecologic Cancer Intergroup (GCIG) defined CA-125 response in recurrent ovarian cancer (ROC) patients. Mathematical modeling may help describe CA-125 decline dynamically and discriminate prognostic kinetic parameters....
Ghodrat, Malihe; Naji, Ali; Komaie-Moghaddam, Haniyeh; Podgornik, Rudolf
2015-05-07
We study the effective interaction mediated by strongly coupled Coulomb fluids between dielectric surfaces carrying quenched, random monopolar charges with equal mean and variance, both when the Coulomb fluid consists only of mobile multivalent counterions and when it consists of an asymmetric ionic mixture containing multivalent and monovalent (salt) ions in equilibrium with an aqueous bulk reservoir. We analyze the consequences that follow from the interplay between surface charge disorder, dielectric and salt image effects, and the strong electrostatic coupling that results from multivalent counterions on the distribution of these ions and the effective interaction pressure they mediate between the surfaces. In a dielectrically homogeneous system, we show that the multivalent counterions are attracted towards the surfaces with a singular, disorder-induced potential that diverges logarithmically on approach to the surfaces, creating a singular but integrable counterion density profile that exhibits an algebraic divergence at the surfaces with an exponent that depends on the surface charge (disorder) variance. This effect drives the system towards a state of lower thermal 'disorder', one that can be described by a renormalized temperature, exhibiting thus a remarkable antifragility. In the presence of an interfacial dielectric discontinuity, the singular behavior of counterion density at the surfaces is removed but multivalent counterions are still accumulated much more strongly close to randomly charged surfaces as compared with uniformly charged ones. The interaction pressure acting on the surfaces displays in general a highly non-monotonic behavior as a function of the inter-surface separation with a prominent regime of attraction at small to intermediate separations. This attraction is caused directly by the combined effects from charge disorder and strong coupling electrostatics of multivalent counterions, which dominate the surface-surface repulsion due to
Pharmacology of drugs for hyperuricemia. Mechanisms, kinetics and interactions.
Pea, F
2005-01-01
The pharmacological profile of drugs for hyperuricemia is reviewed. These agents may reduce the amount of uric acid in blood by means of two different ways: (1) by reducing uric acid production through the inhibition of the enzyme xanthine oxidase (as allopurinol); (2) by increasing uric acid clearance through an inhibition of its renal tubular reabsorption (as probenecid), or through its metabolic conversion to a more soluble compound (as urate oxidase). Allopurinol is rapidly converted in the body to the active metabolite oxypurinol whose total body exposure may be 20-fold greater than that of the parent compound due to a much longer elimination half-life. Allopurinol undergoes several pharmacokinetic interactions with concomitant administered drugs, some of which may be potentially hazardous (especially with mercaptopurine and azathioprine). Probenecid is an uricosuric agent which undergoes extensive hepatic metabolism and whose elimination after high doses may become dose dependent. It may inhibit renal tubular secretion of several coadministered agents, including methotrexate and sulphonylureas. Rasburicase is a recombinant form of the enzyme urate oxidase which catalyzes the conversion of uric acid to the more soluble compound allantoin. Unlike allopurinol, it does not promote accumulation of hypoxanthine and xanthine in plasma, thus preventing the risk of xanthine nephropathy. Rasburicase showed no significant accumulation in children after administration of either 0.15 or 0.20 mg/kg/daily for 5 days. Rasburicase probably undergoes peptide hydrolysis and in in vitro studies was shown neither to inhibit or induce cytochrome P450 isoenzymes nor to interact with several drugs, so that no relevant interaction is expected during cotreatment in patients.
Observation of Spin-Polarons in a strongly interacting Fermi liquid
Zwierlein, Martin
2009-03-01
We have observed spin-polarons in a highly imbalanced mixture of fermionic atoms using tomographic RF spectroscopy. Feshbach resonances allow to freely tune the interactions between the two spin states involved. A single spin down atom immersed in a Fermi sea of spin up atoms can do one of two things: For strong attraction, it can form a molecule with exactly one spin up partner, but for weaker interaction it will spread its attraction and surround itself with a collection of majority atoms. This spin down atom ``dressed'' with a spin up cloud constitutes the spin-polaron. We have observed a striking spectroscopic signature of this quasi-particle for various interaction strengths, a narrow peak in the spin down spectrum that emerges above a broad background. The narrow width signals a long lifetime of the spin-polaron, much longer than the collision rate with spin up atoms, as it must be for a proper quasi-particle. The peak position allows to directly measure the polaron energy. The broad pedestal at high energies reveals physics at short distances and is thus ``molecule-like'': It is exactly matched by the spin up spectra. The comparison with the area under the polaron peak allows to directly obtain the quasi-particle weight Z. We observe a smooth transition from polarons to molecules. At a critical interaction strength of 1/kFa = 0.7, the polaron peak vanishes and spin up and spin down spectra exactly match, signalling the formation of molecules. This is the same critical interaction strength found earlier to separate a normal Fermi mixture from a superfluid molecular Bose-Einstein condensate. The spin-polarons determine the low-temperature phase diagram of imbalanced Fermi mixtures. In principle, polarons can interact with each other and should, at low enough temperatures, form a superfluid of p-wave pairs. We will present a first indication for interactions between polarons.
Quantum criticality of one-dimensional multicomponent Fermi gas with strongly attractive interaction
International Nuclear Information System (INIS)
He, Peng; Jiang, Yuzhu; Guan, Xiwen; He, Jinyu
2015-01-01
Quantum criticality of strongly attractive Fermi gas with SU(3) symmetry in one dimension is studied via the thermodynamic Bethe ansatz (TBA) equations. The phase transitions driven by the chemical potential μ, effective magnetic field H 1 , H 2 (chemical potential biases) are analyzed at the quantum criticality. The phase diagram and critical fields are analytically determined by the TBA equations in the zero temperature limit. High accurate equations of state, scaling functions are also obtained analytically for the strong interacting gases. The dynamic exponent z=2 and correlation length exponent ν=1/2 read off the universal scaling form. It turns out that the quantum criticality of the three-component gases involves a sudden change of density of states of one cluster state, two or three cluster states. In general, this method can be adapted to deal with the quantum criticality of multicomponent Fermi gases with SU(N) symmetry. (paper)
Adsorbate-mediated strong metal-support interactions in oxide-supported Rh catalysts.
Matsubu, John C; Zhang, Shuyi; DeRita, Leo; Marinkovic, Nebojsa S; Chen, Jingguang G; Graham, George W; Pan, Xiaoqing; Christopher, Phillip
2017-02-01
The optimization of supported metal catalysts predominantly focuses on engineering the metal site, for which physical insights based on extensive theoretical and experimental contributions have enabled the rational design of active sites. Although it is well known that supports can influence the catalytic properties of metals, insights into how metal-support interactions can be exploited to optimize metal active-site properties are lacking. Here we utilize in situ spectroscopy and microscopy to identify and characterize a support effect in oxide-supported heterogeneous Rh catalysts. This effect is characterized by strongly bound adsorbates (HCO x ) on reducible oxide supports (TiO 2 and Nb 2 O 5 ) that induce oxygen-vacancy formation in the support and cause HCO x -functionalized encapsulation of Rh nanoparticles by the support. The encapsulation layer is permeable to reactants, stable under the reaction conditions and strongly influences the catalytic properties of Rh, which enables rational and dynamic tuning of CO 2 -reduction selectivity.
Studies of the strong and electroweak interactions at the Z0 pole
International Nuclear Information System (INIS)
Hildreth, M.D.
1995-03-01
This thesis presents studies of the strong and electroweak forces, two of the fundamental interactions that govern the behavior of matter at high energies. The authors have used the hadronic decays of Z 0 bosons produced with the unique experimental apparatus of the e + e - Linear Collider at the Stanford Linear Accelerator Center (SLAC) and the SLAC Large Detector (SLD) for these measurements. Employing the precision tracking capabilities of the SLD, they isolated samples of Z 0 events containing primarily the decays of the Z 0 to a chosen quark type. With an inclusive selection technique, they have tested the flavor independence of the strong coupling, α s by measuring the rates of multi-jet production in isolated samples of light (uds), c, and b quark events. They find: α s uds /α s all 0.987 ± 0.027(stat) ± 0.022(syst) ± 0.022(theory), α s c /α s all = 1.012 ± 0.104(stat) ± 0.102(syst) ± 0.096(theory), α s b /α s all = 1.026 ± 0.041(stat) ± 0.030(theory), which implies that the strong interaction is independent of quark flavor within the present experimental sensitivity. They have also measured the extent of parity-violation in the Z 0 c bar c coupling, given by the parameter A c 0 , using a sample of fully and partially reconstructed D* and D + meson decays and the longitudinal polarization of the SLC electron beam. This sample of charm quark events was derived with selection techniques based on their kinematic properties and decay topologies. They find A c 0 = 0.73 ± 0.22(stat) ± 0.10(syst). This value is consistent with that expected in the electroweak standard model of particle interactions
Pfeiffer, Katherine A; Sorek, Hagit; Roche, Christine M; Strobel, Kathryn L; Blanch, Harvey W; Clark, Douglas S
2015-11-01
The kinetics and mechanisms of protein interactions with solid surfaces are important to fields as diverse as industrial biocatalysis, biomedical engineering, food science, and cell biology. The nonproductive adsorption of cellulase enzymes to lignin, a plant cell wall polymer, reduces their effectiveness in saccharifying biomass. Cellulase has been shown to interact with lignin, but the heterogeneity of lignin surfaces, challenges in measuring irreversible components of these interactions, and fast adsorption rates make quantifying the reaction kinetics difficult. This work employs quartz crystal microgravimetry with dissipation monitoring (QCM-D) for real-time measurement of adsorbed mass on a flat lignin surface. We have developed a method for casting homogeneous lignin films that are chemically similar to lignin found in pretreated biomass, and used QCM-D to compare three models of reversible-irreversible binding behavior: a single-site transition model, a transition model with changing adsorbate footprint, and a two-site transition model. Of the three models tested, the two-site transition model provides the only kinetic mechanism able to describe the behavior of Cel7B binding to lignin. While the direct implications of lignin-cellulase interactions may be limited to biomass deconstruction for renewable energy and green chemistry, the analytical and experimental methods demonstrated in this work are relevant to any system in which the kinetics and reaction mechanism of reversible and irreversible protein adsorption at a solid-liquid interface are important. © 2015 Wiley Periodicals, Inc.
Kinetic energy and added mass of hydrodynamically interacting gas bubbles in liquid
Kok, Jacobus B.W.
1988-01-01
By averaging the basic equations on microscale, expressions are derived for the effective added mass density and the kinetic energy density of a mixture of liquid and gas bubbles. Due to hydrodynamic interaction between the bubbles there appears to be a difference between the effective added mass
Interacting systems far from equilibrium quantum kinetic theory
Morawetz, Klaus
2018-01-01
This book presents an up-to-date formalism of non-equilibrium Green's functions covering different applications ranging from solid state physics, plasma physics, cold atoms in optical lattices up to relativistic transport and heavy ion collisions. Within the Green's function formalism, the basic sets of equations for these diverse systems are similar, and approximations developed in one field can be adapted to another field. The central object is the self-energy which includes all non-trivial aspects of the system dynamics. The focus is therefore on microscopic processes starting from elementary principles for classical gases and the complementary picture of a single quantum particle in a random potential. This provides an intuitive picture of the interaction of a particle with the medium formed by other particles, on which the Green's function is built on.
Interacting multiagent systems kinetic equations and Monte Carlo methods
Pareschi, Lorenzo
2014-01-01
The description of emerging collective phenomena and self-organization in systems composed of large numbers of individuals has gained increasing interest from various research communities in biology, ecology, robotics and control theory, as well as sociology and economics. Applied mathematics is concerned with the construction, analysis and interpretation of mathematical models that can shed light on significant problems of the natural sciences as well as our daily lives. To this set of problems belongs the description of the collective behaviours of complex systems composed by a large enough number of individuals. Examples of such systems are interacting agents in a financial market, potential voters during political elections, or groups of animals with a tendency to flock or herd. Among other possible approaches, this book provides a step-by-step introduction to the mathematical modelling based on a mesoscopic description and the construction of efficient simulation algorithms by Monte Carlo methods. The ar...
Evidence for strong Breit interaction in dielectronic recombination of highly charged heavy ions.
Nakamura, Nobuyuki; Kavanagh, Anthony P; Watanabe, Hirofumi; Sakaue, Hiroyuki A; Li, Yueming; Kato, Daiji; Currell, Fred J; Ohtani, Shunsuke
2008-02-22
Resonant strengths have been measured for dielectronic recombination of Li-like iodine, holmium, and bismuth using an electron beam ion trap. By observing the atomic number dependence of the state-resolved resonant strength, clear experimental evidence has been obtained that the importance of the generalized Breit interaction (GBI) effect on dielectronic recombination increases as the atomic number increases. In particular, it has been shown that the GBI effect is exceptionally strong for the recombination through the resonant state [1s2s(2)2p(1/2)](1).
Viscosity in strongly interacting quantum field theories from black hole physics.
Kovtun, P K; Son, D T; Starinets, A O
2005-03-25
The ratio of shear viscosity to volume density of entropy can be used to characterize how close a given fluid is to being perfect. Using string theory methods, we show that this ratio is equal to a universal value of variant Planck's over 2pi/4pik(B) for a large class of strongly interacting quantum field theories whose dual description involves black holes in anti-de Sitter space. We provide evidence that this value may serve as a lower bound for a wide class of systems, thus suggesting that black hole horizons are dual to the most ideal fluids.
Mechanism for thermal relic dark matter of strongly interacting massive particles.
Hochberg, Yonit; Kuflik, Eric; Volansky, Tomer; Wacker, Jay G
2014-10-24
We present a new paradigm for achieving thermal relic dark matter. The mechanism arises when a nearly secluded dark sector is thermalized with the standard model after reheating. The freeze-out process is a number-changing 3→2 annihilation of strongly interacting massive particles (SIMPs) in the dark sector, and points to sub-GeV dark matter. The couplings to the visible sector, necessary for maintaining thermal equilibrium with the standard model, imply measurable signals that will allow coverage of a significant part of the parameter space with future indirect- and direct-detection experiments and via direct production of dark matter at colliders. Moreover, 3→2 annihilations typically predict sizable 2→2 self-interactions which naturally address the "core versus cusp" and "too-big-to-fail" small-scale structure formation problems.
Kinetics of Endophilin N-BAR Domain Dimerization and Membrane Interactions*
Capraro, Benjamin R.; Shi, Zheng; Wu, Tingting; Chen, Zhiming; Dunn, Joanna M.; Rhoades, Elizabeth; Baumgart, Tobias
2013-01-01
The recruitment to plasma membrane invaginations of the protein endophilin is a temporally regulated step in clathrin-mediated endocytosis. Endophilin is believed to sense or stabilize membrane curvature, which in turn likely depends on the dimeric structure of the protein. The dynamic nature of the membrane association and dimerization of endophilin is thus functionally important and is illuminated herein. Using subunit exchange Förster resonance energy transfer (FRET), we determine dimer dissociation kinetics and find a dimerization equilibrium constant orders of magnitude lower than previously published values. We characterize N-BAR domain membrane association kinetics under conditions where the dimeric species predominates, by stopped flow, observing prominent electrostatic sensitivity of membrane interaction kinetics. Relative to membrane binding, we find that protein monomer/dimer species equilibrate with far slower kinetics. Complementary optical microscopy studies reveal strikingly slow membrane dissociation and an increase of dissociation rate constant for a construct lacking the amphipathic segment helix 0 (H0). We attribute the slow dissociation kinetics to higher-order protein oligomerization on the membrane. We incorporate our findings into a kinetic scheme for endophilin N-BAR membrane binding and find a significant separation of time scales for endophilin membrane binding and subsequent oligomerization. This separation may facilitate the regulation of membrane trafficking phenomena. PMID:23482561
Davis, J. C. Séamus; Lee, Dung-Hai
2013-01-01
Unconventional superconductivity (SC) is said to occur when Cooper pair formation is dominated by repulsive electron–electron interactions, so that the symmetry of the pair wave function is other than an isotropic s-wave. The strong, on-site, repulsive electron–electron interactions that are the proximate cause of such SC are more typically drivers of commensurate magnetism. Indeed, it is the suppression of commensurate antiferromagnetism (AF) that usually allows this type of unconventional superconductivity to emerge. Importantly, however, intervening between these AF and SC phases, intertwined electronic ordered phases (IP) of an unexpected nature are frequently discovered. For this reason, it has been extremely difficult to distinguish the microscopic essence of the correlated superconductivity from the often spectacular phenomenology of the IPs. Here we introduce a model conceptual framework within which to understand the relationship between AF electron–electron interactions, IPs, and correlated SC. We demonstrate its effectiveness in simultaneously explaining the consequences of AF interactions for the copper-based, iron-based, and heavy-fermion superconductors, as well as for their quite distinct IPs. PMID:24114268
Simulation of Quantum Many-Body Dynamics for Generic Strongly-Interacting Systems
Meyer, Gregory; Machado, Francisco; Yao, Norman
2017-04-01
Recent experimental advances have enabled the bottom-up assembly of complex, strongly interacting quantum many-body systems from individual atoms, ions, molecules and photons. These advances open the door to studying dynamics in isolated quantum systems as well as the possibility of realizing novel out-of-equilibrium phases of matter. Numerical studies provide insight into these systems; however, computational time and memory usage limit common numerical methods such as exact diagonalization to relatively small Hilbert spaces of dimension 215 . Here we present progress toward a new software package for dynamical time evolution of large generic quantum systems on massively parallel computing architectures. By projecting large sparse Hamiltonians into a much smaller Krylov subspace, we are able to compute the evolution of strongly interacting systems with Hilbert space dimension nearing 230. We discuss and benchmark different design implementations, such as matrix-free methods and GPU based calculations, using both pre-thermal time crystals and the Sachdev-Ye-Kitaev model as examples. We also include a simple symbolic language to describe generic Hamiltonians, allowing simulation of diverse quantum systems without any modification of the underlying C and Fortran code.
International Nuclear Information System (INIS)
Recami, E.; Tonin Zanchin, V.; Martinez, J.M.
1986-01-01
A unified geometrical approach to strong and gravitational interactions has been recently proposed, based on the classical methods of General Relativity. According to it, hadrons can be regarded as black-hole type solutions of new field equations describing two tensorial metric-field (the ordinary gravitational field, and the strong one). In this paper, we first seize the opportunity for an improved exposition of some elements of the theory relevant to our present scope. Secondly, by extending the Bekenstein-Hawking thermodynamics to the above mentioned strong black-holes (SBH), it is shown: 1) that SBH thermodynamics seems to require a new expansion of our cosmos after its Big Crunch (i.e. that a recontraction of our cosmos has to be followed by a new creation); 2) that a collapsing star with mass M approximately in the range 3 to 5 solar masses, once reached the neutron-star density, could re-explode tending to form a (radiating) object with a diameter of the order of 1 light-day: thus failing to create a gravitational black-hole
Kinetic and docking studies of the interaction of quinones with the quinone reductase active site.
Zhou, Zhigang; Fisher, Derek; Spidel, Jared; Greenfield, Jodi; Patson, Brian; Fazal, Aleem; Wigal, Carl; Moe, Owen A; Madura, Jeffry D
2003-02-25
NAD(P)H/quinone acceptor oxidoreductase type 1 (QR1) protects cells from cytotoxic and neoplastic effects of quinones though two-electron reduction. Kinetic experiments, docking, and binding affinity calculations were performed on a series of structurally varied quinone substrates. A good correlation between calculated and measured binding affinities from kinetic determinations was obtained. The experimental and theoretical studies independently support a model in which quinones (with one to three fused aromatic rings) bind in the QR1 active site utilizing a pi-stacking interaction with the isoalloxazine ring of the FAD cofactor.
Tarun, E I; Karaseva, E I; Metelitsa, D I
1997-01-01
Interactions of three horseradish peroxidase (HRP)-strophanthin conjugates containing one, two, or three glycoside molecules (HRP-Str1, 2, or 3, respectively) with polyclonal anti-HRP antibodies were studied by homogeneous enzyme immunoassay. The total peroxidase activity of free conjugates and their immune complexes was estimated from the oxidation of o-phenylenediamine. The dissociation constants of the immune complexes and the rate constants of their dissociation and formation were determined. The equilibrium and kinetic parameters were determined for the interactions of the HRP-Str2 immune complex with anti-strophanthin and anti-HRP antibodies. The determined equilibrium and kinetic parameters of the HRP-Str interactions with anti-HRP antibodies depended on the molecular weights, sizes, and structures of the antigens studied.
Tubman, Norm; Whaley, Birgitta
The development of exponential scaling methods has seen great progress in tackling larger systems than previously thought possible. One such technique, full configuration interaction quantum Monte Carlo, allows exact diagonalization through stochastically sampling of determinants. The method derives its utility from the information in the matrix elements of the Hamiltonian, together with a stochastic projected wave function, which are used to explore the important parts of Hilbert space. However, a stochastic representation of the wave function is not required to search Hilbert space efficiently and new deterministic approaches have recently been shown to efficiently find the important parts of determinant space. We shall discuss the technique of Adaptive Sampling Configuration Interaction (ASCI) and the related heat-bath Configuration Interaction approach for ground state and excited state simulations. We will present several applications for strongly correlated Hamiltonians. This work was supported through the Scientific Discovery through Advanced Computing (SciDAC) program funded by the U.S. Department of Energy, Office of Science, Advanced Scientific Computing Research and Basic Energy Sciences.
Studies of the strong and electroweak interactions at the Z^{0} pole
Energy Technology Data Exchange (ETDEWEB)
Hildreth, Michael Douglas [Stanford Univ., CA (United States)
1995-03-01
This thesis presents studies of the strong and electroweak forces, two of the fundamental interactions that govern the behavior of matter at high energies. The authors have used the hadronic decays of Z^{0} bosons produced with the unique experimental apparatus of the e^{+}e^{-} Linear Collider at the Stanford Linear Accelerator Center (SLAC) and the SLAC Large Detector (SLD) for these measurements. Employing the precision tracking capabilities of the SLD, they isolated samples of Z^{0} events containing primarily the decays of the Z^{0} to a chosen quark type. With an inclusive selection technique, they have tested the flavor independence of the strong coupling, α_{s} by measuring the rates of multi-jet production in isolated samples of light (uds), c, and b quark events. They find: α$s\\atop{uds}$/α$s\\atop{all}$ 0.987 ± 0.027(stat) ± 0.022(syst) ± 0.022(theory), α$c\\atop{s}$/α$all\\atop{s}$ = 1.012 ± 0.104(stat) ± 0.102(syst) ± 0.096(theory), α$b\\atop{s}$/α$all\\atop{s}$ = 1.026 {+-} 0.041(stat) ± 0.030(theory), which implies that the strong interaction is independent of quark flavor within the present experimental sensitivity. They have also measured the extent of parity-violation in the Z^{0} c$\\bar{c}$ coupling, given by the parameter A $0\\atop{c}$, using a sample of fully and partially reconstructed D* and D^{+} meson decays and the longitudinal polarization of the SLC electron beam. This sample of charm quark events was derived with selection techniques based on their kinematic properties and decay topologies. They find A$0\\atop{c}$ = 0.73 ± 0.22(stat) ± 0.10(syst). This value is consistent with that expected in the electroweak standard model of particle interactions.
Uniform strongly interacting soliton gas in the frame of the Nonlinear Schrodinger Equation
Gelash, Andrey; Agafontsev, Dmitry
2017-04-01
The statistical properties of many soliton systems play the key role in the fundamental studies of integrable turbulence and extreme sea wave formation. It is well known that separated solitons are stable nonlinear coherent structures moving with constant velocity. After collisions with each other they restore the original shape and only acquire an additional phase shift. However, at the moment of strong nonlinear soliton interaction (i.e. when solitons are located close) the wave field are highly complicated and should be described by the theory of inverse scattering transform (IST), which allows to integrate the KdV equation, the NLSE and many other important nonlinear models. The usual approach of studying the dynamics and statistics of soliton wave field is based on relatively rarefied gas of solitons [1,2] or restricted by only two-soliton interactions [3]. From the other hand, the exceptional role of interacting solitons and similar coherent structures - breathers in the formation of rogue waves statistics was reported in several recent papers [4,5]. In this work we study the NLSE and use the most straightforward and general way to create many soliton initial condition - the exact N-soliton formulas obtained in the theory of the IST [6]. We propose the recursive numerical scheme for Zakharov-Mikhailov variant of the dressing method [7,8] and discuss its stability with respect to increasing the number of solitons. We show that the pivoting, i.e. the finding of an appropriate order for recursive operations, has a significant impact on the numerical accuracy. We use the developed scheme to generate statistical ensembles of 32 strongly interacting solitons, i.e. solve the inverse scattering problem for the high number of discrete eigenvalues. Then we use this ensembles as initial conditions for numerical simulations in the box with periodic boundary conditions and study statics of obtained uniform strongly interacting gas of NLSE solitons. Author thanks the
Modeling a nonperturbative spinor vacuum interacting with a strong gravitational wave
Energy Technology Data Exchange (ETDEWEB)
Dzhunushaliev, Vladimir [Al-Farabi Kazakh National University, Department of Theoretical and Nuclear Physics, Almaty (Kazakhstan); Al-Farabi Kazakh National University, Institute of Experimental and Theoretical Physics, Almaty (Kazakhstan); Folomeev, Vladimir [Institute of Physicotechnical Problems and Material Science, NAS of the Kyrgyz Republic, Bishkek (Kyrgyzstan)
2015-07-15
We consider the propagation of strong gravitational waves interacting with a nonperturbative vacuum of spinor fields. To described the latter, we suggest an approximate model. The corresponding Einstein equation has the form of the Schroedinger equation. Its gravitational-wave solution is analogous to the solution of the Schroedinger equation for an electron moving in a periodic potential. The general solution for the periodic gravitational waves is found. The analog of the Kronig-Penney model for gravitational waves is considered. It is shown that the suggested gravitational-wave model permits the existence of weak electric charge and current densities concomitant with the gravitational wave. Based on this observation, a possible experimental verification of the model is suggested. (orig.)
Phase transitions, nonequilibrium dynamics, and critical behavior of strongly interacting systems
Energy Technology Data Exchange (ETDEWEB)
Mottola, E.; Bhattacharya, T.; Cooper, F. [and others
1998-12-31
This is the final report of a three-year, Laboratory Directed Research and Development project at Los Alamos National Laboratory. In this effort, large-scale simulations of strongly interacting systems were performed and a variety of approaches to the nonequilibrium dynamics of phase transitions and critical behavior were investigated. Focus areas included (1) the finite-temperature quantum chromodynamics phase transition and nonequilibrium dynamics of a new phase of matter (the quark-gluon plasma) above the critical temperature, (2) nonequilibrium dynamics of a quantum fields using mean field theory, and (3) stochastic classical field theoretic models with applications to spinodal decomposition and structural phase transitions in a variety of systems, such as spin chains and shape memory alloys.
Description of meson strong weak and electromagnetic interactions in quantum chiral theory
International Nuclear Information System (INIS)
Volkov, M.K.; Ehbert, D.
1979-01-01
The picture of all the principal meson decays of the basic octet has been obtained in the framework of the SU(3)xSU(3) symmetric chiral model of the field theory. An attempt is made to generalize the nonlinear chiral model for the case of charmed hadrons, i.e., a transition from the SU(3)xSU(3) group to the SU(4)xSU(4) group. The authors have succeeded in elucidating unambiguously the role of the Kabibbo angle both in weak and strong interactions (it defines the structure of weak hadron currents and hadron mass splitting in isotopic multiplets). Proceeding from decays of the basic octet mesons it has been shown that the nonlinear chiral SU(3)xSU(3) symmetric theory may be considered as the quantum field theory, which satisfactorily describes the low-energy meson physics in two first orders of the perturbation theory (tree and single-loop approximations)
Particle-Hole Character of the Higgs and Goldstone Modes in Strongly Interacting Lattice Bosons
Di Liberto, M.; Recati, A.; Trivedi, N.; Carusotto, I.; Menotti, C.
2018-02-01
We study the low-energy excitations of the Bose-Hubbard model in the strongly interacting superfluid phase using a Gutzwiller approach. We extract the single-particle and single-hole excitation amplitudes for each mode and report emergent mode-dependent particle-hole symmetry on specific arc-shaped lines in the phase diagram connecting the well-known Lorentz-invariant limits of the Bose-Hubbard model. By tracking the in-phase particle-hole symmetric oscillations of the order parameter, we provide an answer to the long-standing question about the fate of the pure amplitude Higgs mode away from the integer-density critical point. Furthermore, we point out that out-of-phase symmetric oscillations in the gapless Goldstone mode are responsible for a full suppression of the condensate density oscillations. Possible detection protocols are also discussed.
Magnetism and local symmetry breaking in a Mott insulator with strong spin orbit interactions.
Lu, L; Song, M; Liu, W; Reyes, A P; Kuhns, P; Lee, H O; Fisher, I R; Mitrović, V F
2017-02-09
Study of the combined effects of strong electronic correlations with spin-orbit coupling (SOC) represents a central issue in quantum materials research. Predicting emergent properties represents a huge theoretical problem since the presence of SOC implies that the spin is not a good quantum number. Existing theories propose the emergence of a multitude of exotic quantum phases, distinguishable by either local point symmetry breaking or local spin expectation values, even in materials with simple cubic crystal structure such as Ba 2 NaOsO 6 . Experimental tests of these theories by local probes are highly sought for. Our local measurements designed to concurrently probe spin and orbital/lattice degrees of freedom of Ba 2 NaOsO 6 provide such tests. Here we show that a canted ferromagnetic phase which is preceded by local point symmetry breaking is stabilized at low temperatures, as predicted by quantum theories involving multipolar spin interactions.
Smolyansky, S. A.; Prozorkevich, A. V.; Dmitriev, V. V.; Tarakanov, A. V.
2014-11-01
In this paper, the dynamical Schwinger effect of vacuum creation of electron-positron pairs driven by an intense laser pulse is studied on the basis of correct quantum kinetic theory. In the general case, the numerical solutions of corresponding system of kinetic equations exhibit complex time dependence which makes the analysis of the physical processes complicated. In particular, the question of secondary effects, such as creation of annihilation photons from the focus spot of the colliding laser beams, remains an important open problem. In our previous work [S. A. Smolyansky, M. Bonitz and A. V. Prozorkevich, Contrib. Plasma Phys.53 (2013) 788], we presented a perturbation theory which is able to capture the dominant time dependence of the produced electron-positron pair distribution during the pulse (quasiparticle excitations). In the present work, we develop appreciably this approximation scheme. We demonstrate effectiveness of the proposed method for solution of such kind nonstationary problems in the simplest models of the laser field. However, this approach opens perspective for search of the relevant approximate solutions in kinetic theory of the e+e- quasiparticle plasma for the more realistic field models (arbitrary polarization, space inhomogeneous, etc).
Li, Xiangrong; Wang, Kaiwei; Peng, Yanru
2018-04-25
The interaction of nanoparticles (NPs) with proteins is a topic of high relevance for the medical application of nanomaterials. In the study, a comprehensive investigation was performed for the binding properties of silver nanoparticles (AgNPs) to pepsin. The results indicate that the binding of AgNPs to pepsin may be a static quenching mechanism. Thermodynamic analysis reveals that AgNPs binds to pepsin is synergistically driven by enthalpy and entropy, and the major driving forces are hydrophobic and electrostatic interactions. Synchronous fluorescence spectroscopy shows that AgNPs may induce microenvironmental changes of pepsin. The hydrophobicity of Trp is increased while the hydrophility of Tyr is increased. The adsorption of pepsin on AgNPs was analyzed by Langmuir and Freundlich models, suggesting that the equilibrium adsorption data fit well with Freundlich model. The equilibrium adsorption data were modeled using the pseudo-first-order and pseudo-second-order kinetic equations. The results indicate that pseudo-second-order kinetic equation better describes the adsorption kinetics. The study provides an accurate and full basic data for clarifying the binding mechanism, adsorption isotherms and kinetic behaviors of AgNPs with pepsin. These fundamental works will provide some new insights into the safe and effective application of AgNPs in biological and medical areas. Copyright © 2018 Elsevier B.V. All rights reserved.
Thermodynamic activity-based intrinsic enzyme kinetic sheds light on enzyme-solvent interactions.
Grosch, Jan-Hendrik; Wagner, David; Nistelkas, Vasilios; Spieß, Antje C
2017-01-01
The reaction medium has major impact on biocatalytic reaction systems and on their economic significance. To allow for tailored medium engineering, thermodynamic phenomena, intrinsic enzyme kinetics, and enzyme-solvent interactions have to be discriminated. To this end, enzyme reaction kinetic modeling was coupled with thermodynamic calculations based on investigations of the alcohol dehydrogenase from Lactobacillus brevis (LbADH) in monophasic water/methyl tert-butyl ether (MTBE) mixtures as a model solvent. Substrate concentrations and substrate thermodynamic activities were varied separately to identify the individual thermodynamic and kinetic effects on the enzyme activity. Microkinetic parameters based on concentration and thermodynamic activity were derived to successfully identify a positive effect of MTBE on the availability of the substrate to the enzyme, but a negative effect on the enzyme performance. In conclusion, thermodynamic activity-based kinetic modeling might be a suitable tool to initially curtail the type of enzyme-solvent interactions and thus, a powerful first step to potentially understand the phenomena that occur in nonconventional media in more detail. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 33:96-103, 2017. © 2016 American Institute of Chemical Engineers.
Kanske, Philipp; Böckler, Anne; Trautwein, Fynn-Mathis; Parianen Lesemann, Franca H; Singer, Tania
2016-09-01
Although the processes that underlie sharing others' emotions (empathy) and understanding others' mental states (mentalizing, Theory of Mind) have received increasing attention, it is yet unclear how they relate to each other. For instance, are people who strongly empathize with others also more proficient in mentalizing? And (how) do the neural networks supporting empathy and mentalizing interact? Assessing both functions simultaneously in a large sample (N = 178), we show that people's capacities to empathize and mentalize are independent, both on a behavioral and neural level. Thus, strong empathizers are not necessarily proficient mentalizers, arguing against a general capacity of social understanding. Second, we applied dynamic causal modeling to investigate how the neural networks underlying empathy and mentalizing are orchestrated in naturalistic social settings. Results reveal that in highly emotional situations, empathic sharing can inhibit mentalizing-related activity and thereby harm mentalizing performance. Taken together, our findings speak against a unitary construct of social understanding and suggest flexible interplay of distinct social functions. © The Author (2016). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.
Observation of quantum-limited spin transport in strongly interacting two-dimensional Fermi gases
Olsen, Ben A.; Luciuk, Chris; Smale, Scott; Böttcher, Florian; Sharum, Haille; Trotzky, Stefan; Enss, Tilman; Thywissen, Joseph H.
2017-04-01
Conjectured quantum bounds on transport appear to be respected in many strongly interacting many-body systems. Since transport occurs as a system relaxes to equilibrium, many such bounds can be recast as an upper bound on the local relaxation rate kB T / ℏ . Systems saturating this ``Planckian'' bound lack well defined quasiparticles promoting transport. We measure the transport properties of 2D ultracold Fermi gases of 40K during transverse demagnetization in a magnetic field gradient. Using a phase-coherent spin-echo sequence, we distinguish bare spin diffusion from the Leggett-Rice effect, in which demagnetization is slowed by the precession of spin current around the local magnetization. When the 2D scattering length is tuned near an s-wave Feshbach resonance to be comparable to the inverse Fermi wave vector kF- 1 , we find that the bare transverse spin diffusivity reaches a minimum of 1 . 7(6) ℏ / m . Demagnetization is also reflected in the growth rate of the s-wave contact, observed using time-resolved rf spectroscopy. At unitarity, the contact rises to 0 . 28(3) kF2 per particle, measuring the breaking of scaling symmetry. Our observations support the conjecture that under strong scattering, the local relaxation rate is bounded from above by kB T / ℏ .
New precision era of experiments on strong interaction with strangeness at DAFNE/LNF-INFN
Directory of Open Access Journals (Sweden)
Ishiwatari T.
2014-03-01
Full Text Available The strong-interaction shifts and widths of kaonic hydrogen, deuterium, 3He, and 4He were measured in the SIDDHARTA experiment. The most precise values of the shift and width of the kaonic hydrogen 1s state were determined to be ϵ1s = −283 ± 36(stat±6(syst eV and Γ1s = 541±89(stat±22(syst eV. The upper limit of the kaonic deuterium Kα yield was found to be ≤ 0.39%. In addition, the shifts and widths of the kaonic 3He and 4He 2p states were determined to be ϵ2p(3He = −2 ± 2(stat ± 4(syst eV and Γ2p(3He = 6 ± 6(stat ± 7(syst eV; ϵ2p(4He = +5 ± 3(stat ± 4(syst eV and Γ2p(4He = 14 ± 8(stat ± 5(syst eV. These values are important for the constraints of the low-energy K¯N$\\bar KN$ interaction in theoretical approaches.
Interaction of a strong stellar wind with a mutiphase interstellar medium
International Nuclear Information System (INIS)
Wolff, M.T.
1986-01-01
The interaction of a strong stellar wind with the interstellar medium produces a hot, low density cavity surrounded by a swept-up shell of gas. This cavity-plus-shell structure is collectively called an interstellar bubble. In calculations prior to this work, researchers assumed that the interstellar medium surrounding the wind-blowing star was described by a constant density and temperature (i.e., was homogeneous). This dissertation improves on these earlier calculations by assuming that the interstellar medium surrounding the star is inhomogeneous or multiphase. Gas flows are modeled by assuming that the inhomogeneous phases of the interstellar medium (the clouds) and the intercloud gas form two distinct but interacting fluid that can exchange mass momentum and energy with each other. In one set of calculations, it is assumed that thermal conductive evaporation of clouds brought about by the clouds sitting inside a region of hot (T ≅ 10 6 K) gas is the only mass exchange process operation between the clouds and intercloud fluid. It was found that the mass injection from the clouds to the intercloud gas via the process of thermal evaporation can significantly modify the structure of the interstellar bubble from that found in previous studies
Budget of Turbulent Kinetic Energy in a Shock Wave Boundary-Layer Interaction
Vyas, Manan A.; Waindim, Mbu; Gaitonde, Datta V.
2016-01-01
Implicit large-eddy simulation (ILES) of a shock wave/boundary-layer interaction (SBLI) was performed. Quantities present in the exact equation of the turbulent kinetic energy transport were accumulated and used to calculate terms like production, dissipation, molecular diffusion, and turbulent transport. The present results for a turbulent boundary layer were validated by comparison with direct numerical simulation data. It was found that a longer development domain was necessary for the boundary layer to reach an equilibrium state and a finer mesh resolution would improve the predictions. In spite of these findings, trends of the present budget match closely with that of the direct numerical simulation. Budgets for the SBLI region are presented at key axial stations. These budgets showed interesting dynamics as the incoming boundary layer transforms and the terms of the turbulent kinetic energy budget change behavior within the interaction region.
Kinetic theory for radiation interacting with sound waves in ultrarelativistic pair plasmas
International Nuclear Information System (INIS)
Marklund, Mattias; Shukla, Padma K.; Stenflo, Lennart
2006-01-01
A kinetic theory for radiation interacting with sound waves in an ultrarelativistic electron-positron plasma is developed. It is shown that the effect of a spatial spectral broadening of the electromagnetic pulse is to introduce a reduction of the growth rates for the decay and modulational instabilities. Such spectral broadening could be due to a finite pulse coherence length, or through the use of random phase filters, and would stabilize the propagation of electromagnetic pulses
Kinetic contributions to gating by interactions unique to N-methyl-D-aspartate (NMDA) receptors.
Borschel, William F; Cummings, Kirstie A; Tindell, LeeAnn K; Popescu, Gabriela K
2015-10-30
Among glutamate-gated channels, NMDA receptors produce currents that subside with unusually slow kinetics, and this feature is essential to the physiology of central excitatory synapses. Relative to the homologous AMPA and kainate receptors, NMDA receptors have additional intersubunit contacts in the ligand binding domain that occur at both conserved and non-conserved sites. We examined GluN1/GluN2A single-channel currents with kinetic analyses and modeling to probe these class-specific intersubunit interactions for their role in glutamate binding and receptor gating. We found that substitutions that eliminate such interactions at non-conserved sites reduced stationary gating, accelerated deactivation, and imparted sensitivity to aniracetam, an AMPA receptor-selective positive modulator. Abolishing unique contacts at conserved sites also reduced stationary gating and accelerated deactivation. These results show that contacts specific to NMDA receptors, which brace the heterodimer interface within the ligand binding domain, stabilize actively gating receptor conformations and result in longer bursts and slower deactivations. They support the view that the strength of the heterodimer interface modulates gating in both NMDA and non-NMDA receptors and that unique interactions at this interface are responsible in part for basic differences between the kinetics of NMDA and non-NMDA currents at glutamatergic synapses. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.
Kinetic Contributions to Gating by Interactions Unique to N-methyl-d-aspartate (NMDA) Receptors*
Borschel, William F.; Cummings, Kirstie A.; Tindell, LeeAnn K.; Popescu, Gabriela K.
2015-01-01
Among glutamate-gated channels, NMDA receptors produce currents that subside with unusually slow kinetics, and this feature is essential to the physiology of central excitatory synapses. Relative to the homologous AMPA and kainate receptors, NMDA receptors have additional intersubunit contacts in the ligand binding domain that occur at both conserved and non-conserved sites. We examined GluN1/GluN2A single-channel currents with kinetic analyses and modeling to probe these class-specific intersubunit interactions for their role in glutamate binding and receptor gating. We found that substitutions that eliminate such interactions at non-conserved sites reduced stationary gating, accelerated deactivation, and imparted sensitivity to aniracetam, an AMPA receptor-selective positive modulator. Abolishing unique contacts at conserved sites also reduced stationary gating and accelerated deactivation. These results show that contacts specific to NMDA receptors, which brace the heterodimer interface within the ligand binding domain, stabilize actively gating receptor conformations and result in longer bursts and slower deactivations. They support the view that the strength of the heterodimer interface modulates gating in both NMDA and non-NMDA receptors and that unique interactions at this interface are responsible in part for basic differences between the kinetics of NMDA and non-NMDA currents at glutamatergic synapses. PMID:26370091
Role of strongly interacting additives in tuning the structure and properties of polymer systems
Daga, Vikram Kumar
Block copolymer (BCP) nanocomposites are an important class of hybrid materials in which the BCP guides the spatial location and the periodic assembly of the additives. High loadings of well-dispersed nanofillers are generally important for many applications including mechanical reinforcing of polymers. In particular the composites shown in this work might find use as etch masks in nanolithography, or for enabling various phase selective reactions for new materials development. This work explores the use of hydrogen bonding interactions between various additives (such as homopolymers and non-polymeric additives) and small, disordered BCPs to cause the formation of well-ordered morphologies with small domains. A detailed study of the organization of homopolymer chains and the evolution of structure during the process of ordering is performed. The results demonstrate that by tuning the selective interaction of the additive with the incorporating phase of the BCP, composites with significantly high loadings of additives can be formed while maintaining order in the BCP morphology. The possibility of high and selective loading of additives in one of the phases of the ordered BCP composite opens new avenues due to high degree of functionalization and the proximity of the additives within the incorporating phase. This aspect is utilized in one case for the formation of a network structure between adjoining additive cores to derive mesoporous inorganic materials with their structures templated by the BCP. The concept of additive-driven assembly is extended to formulate BCPadditive blends with an ability to undergo photo-induced ordering. Underlying this strategy is the ability to transition a weakly interacting additive to its strongly interacting form. This strategy provides an on-demand, non-intrusive route for formation of well-ordered nanostructures in arbitrarily defined regions of an otherwise disordered material. The second area explored in this dissertation deals
Kivotides, Demosthenes
2018-03-01
The interactions between vortex tubes and magnetic-flux rings in incompressible magnetohydrodynamics are investigated at high kinetic and magnetic Reynolds numbers, and over a wide range of the interaction parameter. The latter is a measure of the turnover time of the large-scale fluid motions in units of the magnetic damping time, or of the strength of the Lorentz force in units of the inertial force. The small interaction parameter results, which are related to kinematic turbulent dynamo studies, indicate the evolution of magnetic rings into flattened spirals wrapped around the vortex tubes. This process is also observed at intermediate interaction parameter values, only now the Lorentz force creates new vortical structures at the magnetic spiral edges, which have a striking solenoid vortex-line structure, and endow the flattened magnetic-spiral surfaces with a curvature. At high interaction parameter values, the decisive physical factor is Lorentz force effects. The latter create two (adjacent to the magnetic ring) vortex rings that reconnect with the vortex tube by forming an intriguing, serpentinelike, vortex-line structure, and generate, in turn, two new magnetic rings, adjacent to the initial one. In this regime, the morphologies of the vorticity and magnetic field structures are similar. The effects of these structures on kinetic and magnetic energy spectra, as well as on the direction of energy transfer between flow and magnetic fields, are also indicated.
Revisiting the density scaling of the non-interacting kinetic energy.
Borgoo, Alex; Teale, Andrew M; Tozer, David J
2014-07-28
Scaling relations play an important role in the understanding and development of approximate functionals in density functional theory. Recently, a number of these relationships have been redefined in terms of the Kohn-Sham orbitals [Calderín, Phys. Rev. A: At., Mol., Opt. Phys., 2013, 86, 032510]. For density scaling the author proposed a procedure involving a multiplicative scaling of the Kohn-Sham orbitals whilst keeping their occupation numbers fixed. In the present work, the differences between this scaling with fixed occupation numbers and that of previous studies, where the particle number change implied by the scaling was accommodated through the use of the grand canonical ensemble, are examined. We introduce the terms orbital and ensemble density scaling for these approaches, respectively. The natural ambiguity of the density scaling of the non-interacting kinetic energy functional is examined and the ancillary definitions implicit in each approach are highlighted and compared. As a consequence of these differences, Calderín recovered a homogeneity of degree 1 for the non-interacting kinetic energy functional under orbital scaling, contrasting recent work by the present authors [J. Chem. Phys., 2012, 136, 034101] where the functional was found to be inhomogeneous under ensemble density scaling. Furthermore, we show that the orbital scaling result follows directly from the linearity and the single-particle nature of the kinetic energy operator. The inhomogeneity of the non-interacting kinetic energy functional under ensemble density scaling can be quantified by defining an effective homogeneity. This quantity is shown to recover the homogeneity values for important approximate forms that are exact for limiting cases such as the uniform electron gas and one-electron systems. We argue that the ensemble density scaling provides more insight into the development of new functional forms.
Numerical simulation of wave-current interaction under strong wind conditions
Larrañaga, Marco; Osuna, Pedro; Ocampo-Torres, Francisco Javier
2017-04-01
Although ocean surface waves are known to play an important role in the momentum and other scalar transfer between the atmosphere and the ocean, most operational numerical models do not explicitly include the terms of wave-current interaction. In this work, a numerical analysis about the relative importance of the processes associated with the wave-current interaction under strong off-shore wind conditions in Gulf of Tehuantepec (the southern Mexican Pacific) was carried out. The numerical system includes the spectral wave model WAM and the 3D hydrodynamic model POLCOMS, with the vertical turbulent mixing parametrized by the kappa-epsilon closure model. The coupling methodology is based on the vortex-force formalism. The hydrodynamic model was forced at the open boundaries using the HYCOM database and the wave model was forced at the open boundaries by remote waves from the southern Pacific. The atmospheric forcing for both models was provided by a local implementation of the WRF model, forced at the open boundaries using the CFSR database. The preliminary analysis of the model results indicates an effect of currents on the propagation of the swell throughout the study area. The Stokes-Coriolis term have an impact on the transient Ekman transport by modifying the Ekman spiral, while the Stokes drift has an effect on the momentum advection and the production of TKE, where the later induces a deepening of the mixing layer. This study is carried out in the framework of the project CONACYT CB-2015-01 255377 and RugDiSMar Project (CONACYT 155793).
Strongly self-interacting vector dark matter via freeze-in
Duch, Mateusz; Grzadkowski, Bohdan; Huang, Da
2018-01-01
We study a vector dark matter (VDM) model in which the dark sector couples to the Standard Model sector via a Higgs portal. If the portal coupling is small enough the VDM can be produced via the freeze-in mechanism. It turns out that the electroweak phase transition have a substantial impact on the prediction of the VDM relic density. We further assume that the dark Higgs boson which gives the VDM mass is so light that it can induce strong VDM self-interactions and solve the small-scale structure problems of the Universe. As illustrated by the latest LUX data, the extreme smallness of the Higgs portal coupling required by the freeze-in mechanism implies that the dark matter direct detection bounds are easily satisfied. However, the model is well constrained by the indirect detections of VDM from BBN, CMB, AMS-02, and diffuse γ/X-rays. Consequently, only when the dark Higgs boson mass is at most of O (keV) does there exist a parameter region which leads to a right amount of VDM relic abundance and an appropriate VDM self-scattering while satisfying all other constraints simultaneously.
Strongly interacting Fermi systems in 1/N expansion: From cold atoms to color superconductivity
International Nuclear Information System (INIS)
Abuki, Hiroaki; Brauner, Tomas
2008-01-01
We investigate the 1/N expansion proposed recently as a strategy to include quantum fluctuation effects in the nonrelativistic, attractive Fermi gas at and near unitarity. We extend the previous results by calculating the next-to-leading order corrections to the critical temperature along the whole crossover from Bardeen-Cooper-Schrieffer (BCS) superconductivity to Bose-Einstein condensation. We demonstrate explicitly that the extrapolation from the mean-field approximation, based on the 1/N expansion, provides a useful approximation scheme only on the BCS side of the crossover. We then apply the technique to the study of strongly interacting relativistic many-fermion systems. Having in mind the application to color superconductivity in cold dense quark matter, we develop, within a simple model, a formalism suitable to compare the effects of order parameter fluctuations in phases with different pairing patterns. Our main conclusion is that the relative correction to the critical temperature is to a good accuracy proportional to the mean-field ratio of the critical temperature and the chemical potential. As a consequence, it is significant even rather deep in the BCS regime, where phenomenologically interesting values of the quark-quark coupling are expected. Possible impact on the phase diagram of color-superconducting quark matter is discussed.
Three-dimensional RAGE Simulations of Strong Shocks Interacting with Sapphire Balls
Wilde, B. H.; Coker, R. F.; Rosen, P. A.; Foster, J. M.; Hartigan, P.; Carver, R.; Blue, B. E.; Hansen, J. F.
2007-11-01
The goal of our 2007-2008 NLUF experiments at the OMEGA laser facility is to investigate the physics associated with the interaction of strong shocks and jets with clumpy media. These experiments have close analogs with structures observed in a variety of astrophysical flows, including jets from young stars, outflows from planetary nebulae, and extragalactic jets. In these experiments, a multi-mega bar shock is created in a plastic layer by heating a hohlraum to 190 eV temperature with 5 kJ of laser energy. The shock enters a 0.3 g/cc RF foam into which are embedded 500 micron diameter sapphire balls. The shock shears off the ball such that it creates thin two-dimensional sheets of sapphire which subsequently break up and undergo the three-dimensional Widnall instability (Widnall, S. E., Bliss, D. B., & Tsai, C. 1974, J. Fluid Mech., 66, 35). The time evolution of the ball/balls is diagnosed with dual-axes point-projection radiography. In this poster, we discuss the results of high-resolution three-dimensional radiation-hydrodynamic simulations with the adaptive-mesh-refinement RAGE code of single and multiple balls. Comparisons with data from our August shots will be made.
Introduction to gauge theories of the strong, weak, and electromagnetic interactions
International Nuclear Information System (INIS)
Quigg, C.
1980-07-01
The plan of these notes is as follows. Chapter 1 is devoted to a brief evocative review of current beliefs and prejudices that form the context for the discussion to follow. The idea of Gauge Invariance is introduced in Chapter 2, and the connection between conservation laws and symmetries of the Lagrangian is recalled. Non-Abelian gauge field theories are constructed in Chapter 3, by analogy with the familiar case of electromagnetism. The Yang-Mills theory based upon isospin symmetry is constructed explicitly, and the generalization is made to other gauge groups. Chapter 4 is concerned with spontaneous symmetry breaking and the phenomena that occur in the presence or absence of local gauge symmetries. The existence of massless scalar fields (Goldstone particles) and their metamorphosis by means of the Higgs mechanism are illustrated by simple examples. The Weinberg-Salam model is presented in Chapter 5, and a brief resume of applications to experiment is given. Quantum Chromodynamics, the gauge theory of colored quarks and gluons, is developed in Chapter 6. Asymptotic freedom is derived schematically, and a few simple applications of perturbative QCD ae exhibited. Details of the conjectured confinement mechanism are omitted. The strategy of grand unified theories of the strong, weak, and electromagnetic interactions is laid out in Chapter 7. Some properties and consequences of the minimal unifying group SU(5) are presented, and the gauge hierarchy problem is introduced in passing. The final chapter contains an essay on the current outlook: aspirations, unanswered questions, and bold scenarios
International Nuclear Information System (INIS)
Dubovitskii, V.A.; Pavlov, G.A.; Krasnikov, Yu.G.
1996-01-01
Thermodynamic analysis of media with strong interparticle (Coulomb) interaction is presented. A method for constructing isotherms is proposed for a medium described by a closed multicomponent thermodynamic model. The method is based on choosing an appropriate nondegenerate frame of reference in the extended space of thermodynamic variables and provides efficient thermodynamic calculations in a wide range of parameters, for an investigation of phase transitions of the first kind, and for determining both the number of phases and coexistence curves. A number of approximate thermodynamic models of hydrogen plasma are discussed. The approximation corresponding to the n5/2 law, in which the effects of particle attraction and repulsion are taken into account qualitatively, is studied. This approximation allows studies of thermodynamic properties of a substance for a wide range of parameters. In this approximation, for hydrogen at a constant temperature, various properties of the degree of ionization are revealed. In addition, the parameters of the second critical point are found under conditions corresponding to the Jovian interior
International Nuclear Information System (INIS)
Carruthers, P.; Thews, R.L.
1988-01-01
This paper contains progress information on the following topics in High Energy Physics: strong, electromagnetic, and weak interactions; aspects of quark-gluon models for hadronic interactions, decays, and structure; the dynamical generation of a mass gap and the role and truthfulness of perturbation theory; statistical and dynamical aspects of hadronic multiparticle production; and realization of chiral symmetry and temperature effects in supersymmetric theories
Interaction and kinetic analysis for coal and biomass co-gasification by TG-FTIR.
Xu, Chaofen; Hu, Song; Xiang, Jun; Zhang, Liqi; Sun, Lushi; Shuai, Chao; Chen, Qindong; He, Limo; Edreis, Elbager M A
2014-02-01
This study aims to investigate the interaction and kinetic behavior of CO2 gasification of coal, biomass and their blends by thermogravimetry analysis (TG). The gas products evolved from gasification were measured online with Fourier Transform Infrared Spectroscopy (FTIR) coupled with TG. Firstly, TG experiments indicated that interaction between the coals and biomasses mainly occurred during co-gasification process. The most significant synergistic interaction occurred for LN with SD at the blending mass ratio 4:1. Furthermore, thermal kinetic analysis indicated that the activation energy involved in co-gasification decreased as the SD content increased until the blending ratio of SD with coal reached 4:1. The rise of the frequency factor indicated that the increase of SD content favored their synergistic interaction. Finally, FTIR analysis of co-gasification of SD with LN indicated that except for CO, most gases including CH3COOH, C6H5OH, H2O, etc., were detected at around 50-700°C. Copyright © 2014. Published by Elsevier Ltd.
A Uniﬁed Theory of Interaction: Gravitation, Electrodynamics and the Strong Force
Directory of Open Access Journals (Sweden)
Wagener P.
2009-01-01
Full Text Available A unified model of gravitation and electromagnetism is extended to derive the Yukawa potential for the strong force. The model satisfies the fundamental characteristics of the strong force and calculates the mass of the pion.
Multia, Evgen; Sirén, Heli; Andersson, Karl; Samuelsson, Jörgen; Forssén, Patrik; Fornstedt, Torgny; Öörni, Katariina; Jauhiainen, Matti; Riekkola, Marja-Liisa
2017-02-01
Two complementary instrumental techniques were used, and the data generated was processed with advanced numerical tools to investigate the interactions between anti-human apoB-100 monoclonal antibody (anti-apoB-100 Mab) and apoB-100 containing lipoproteins. Partial Filling Affinity Capillary Electrophoresis (PF-ACE) combined with Adsorption Energy Distribution (AED) calculations provided information on the heterogeneity of the interactions without any a priori model assumptions. The AED calculations evidenced a homogenous binding site distribution for the interactions. Quartz Crystal Microbalance (QCM) studies were used to evaluate thermodynamics and kinetics of the Low-Density Lipoprotein (LDL) and anti-apoB-100 Mab interactions. High affinity and selectivity were observed, and the emerging data sets were analysed with so called Interaction Maps. In thermodynamic studies, the interaction between LDL and anti-apoB-100 Mab was found to be predominantly enthalpy driven. Both techniques were also used to study antibody interactions with Intermediate-Density (IDL) and Very Low-Density (VLDL) Lipoproteins. By screening affinity constants for IDL-VLDL sample in a single injection we were able to distinguish affinity constants for both subpopulations using the numerical Interaction Map tool. Copyright © 2016 Elsevier Inc. All rights reserved.
International Nuclear Information System (INIS)
Markin, Craig J.; Spyracopoulos, Leo
2012-01-01
NMR-monitored chemical shift titrations for the study of weak protein–ligand interactions represent a rich source of information regarding thermodynamic parameters such as dissociation constants (K D ) in the micro- to millimolar range, populations for the free and ligand-bound states, and the kinetics of interconversion between states, which are typically within the fast exchange regime on the NMR timescale. We recently developed two chemical shift titration methods wherein co-variation of the total protein and ligand concentrations gives increased precision for the K D value of a 1:1 protein–ligand interaction (Markin and Spyracopoulos in J Biomol NMR 53: 125–138, 2012). In this study, we demonstrate that classical line shape analysis applied to a single set of 1 H– 15 N 2D HSQC NMR spectra acquired using precise protein–ligand chemical shift titration methods we developed, produces accurate and precise kinetic parameters such as the off-rate (k off ). For experimentally determined kinetics in the fast exchange regime on the NMR timescale, k off ∼ 3,000 s −1 in this work, the accuracy of classical line shape analysis was determined to be better than 5 % by conducting quantum mechanical NMR simulations of the chemical shift titration methods with the magnetic resonance toolkit GAMMA. Using Monte Carlo simulations, the experimental precision for k off from line shape analysis of NMR spectra was determined to be 13 %, in agreement with the theoretical precision of 12 % from line shape analysis of the GAMMA simulations in the presence of noise and protein concentration errors. In addition, GAMMA simulations were employed to demonstrate that line shape analysis has the potential to provide reasonably accurate and precise k off values over a wide range, from 100 to 15,000 s −1 . The validity of line shape analysis for k off values approaching intermediate exchange (∼100 s −1 ), may be facilitated by more accurate K D measurements from NMR
Zwierlein, Martin
2017-04-01
Strongly interacting fermions govern physics at all length scales, from nuclear matter to modern electronic materials and neutron stars. The interplay of the Pauli principle with strong interactions can give rise to exotic properties that we do not understand even at a qualitative level. In recent years, ultracold Fermi gases of atoms have emerged as a new type of strongly interacting fermionic matter that can be created and studied in the laboratory with exquisite control. Feshbach resonances allow for unitarity limited interactions, leading to scale invariance, universal thermodynamics and a superfluid phase transition already at 17 Trapped in optical lattices, fermionic atoms realize the Fermi-Hubbard model, believed to capture the essence of cuprate high-temperature superconductors. Here, a microscope allows for single-atom, single-site resolved detection of density and spin correlations, revealing the Pauli hole as well as anti-ferromagnetic and doublon-hole correlations. Novel states of matter are predicted for fermions interacting via long-range dipolar interactions. As an intriguing candidate we created stable fermionic molecules of NaK at ultralow temperatures featuring large dipole moments and second-long spin coherence times. In some of the above examples the experiment outperformed the most advanced computer simulations of many-fermion systems, giving hope for a new level of understanding of strongly interacting fermions.
Directory of Open Access Journals (Sweden)
A.Y. Klimenko
2017-05-01
Full Text Available This work investigates the influence of directional properties of decoherence on kinetics rate equations. The physical reality is understood as a chain of unitary and decoherence events. The former are quantum-deterministic, while the latter introduce uncertainty and increase entropy. For interactions of matter and antimatter, two approaches are considered: symmetric decoherence, which corresponds to conventional symmetric (CP-invariant thermodynamics, and antisymmetric decoherence, which corresponds to antisymmetric (CPT-invariant thermodynamics. Radiation, in its interactions with matter and antimatter, is shown to be decoherence-neutral. The symmetric and antisymmetric assumptions result in different interactions of radiation with matter and antimatter. The theoretical predictions for these differences are testable by comparing absorption (emission of light by thermodynamic systems made of matter and antimatter. Canonical typicality for quantum mixtures is briefly discussed in Appendix A.
Kinetics of interaction from low-energy-ion bombardment of surfaces
International Nuclear Information System (INIS)
Horton, C.C.
1988-01-01
The kinetics of interaction from low energy oxygen ion bombardment of carbon and Teflon surfaces have been investigated. The surfaces were bombarded with 4.5 to 93 eV oxygen ions and emitted species were observed with a mass spectrometer. To obtain the kinetic information, the ion beam was square pulse modulated and reaction products were observed as a function of time. The kinetic information is contained in the response of the emitted species to the pulsed ion beam. Oxygen bombardment of carbon produced CO in three parallel branches with each following an adsorption-desorption process. The fast branch, with a rate constants of 12,000/sec, appeared to be sputter induced an was absent below about 19 eV. The medium and slow branches, with rate constants of 850/sec and 45/sec respectively, has little energy dependence and appeared to be due to chemical sputtering from two sites. The ratio of the fraction of the medium branch to that of the slow was constant at 1:3. The bombardment of Teflon produced CF in two parallel branches, with one following a series process and the other an adsorb-desorb process. The rate constant of the other branch were 22,000/sec and 7,000/sec and the rate constant of the other branch was 90/sec. The total signal fell monotonically with decreasing ion energy with the fraction for each branch holding constant at 71% for the series and 29% for the adsorb-desorb
Energy Technology Data Exchange (ETDEWEB)
Chan, J.; DePorcel, L.; Dixon, L. [eds.
1997-06-01
This conference explored the role of the strong interaction in the physics of hadrons and partons. The Institute attracted 239 physicists from 16 countries to hear lectures on the underlying theory of Quantum Chromodynamics, modern theoretical calculational techniques, and experimental investigation of the strong interaction as it appears in various phenomena. Different regimes in which one can calculate reliably in QCD were addressed in series of lectures on perturbation theory, lattice gauge theories, and heavy quark expansions. Studies of QCD in hadron-hadron collisions, electron-positron annihilation, and electron-proton collisions all give differing perspectives on the strong interaction--from low-x to high-Q{sup 2}. Experimental understanding of the production and decay of heavy quarks as well as the lighter meson states has continued to evolve over the past years, and these topics were also covered at the School. Selected papers have been indexed separately for inclusion in the Energy Science and Technology Database.
International Nuclear Information System (INIS)
Santilli, R.M.
1981-01-01
A primary objective of the research is the achievement of clear experimental knowledge on the intrinsic characteristics of particles (such as magnetic moment, spin, space parity, etc.) under strong interactions. These characteristics, when known, have been measured a number of times, but all times for particles under long range electromagnetic interactions (e.g., for bubble chamber techniques). The same characteristics are then generally assumed to persist under the different physical conditions of the strong interactions, while no direct or otherwise final measurement under strong interactions exists at this time. The advocated physical knowledge is clearly important for controlled fusion, as well as for a serious study of the foundations of strong interactions. The paper initiates the study by considering the following alternatives. A: the electromagnetic characteristics of particles persist in the transition to the strong; or B: variations in these characteristics are physically conceivable, mathematically treatable, and experimentally detectable. The need to conduct additional experiments, and achieve a final resolution of the issue, is stressed throughout the paper. In the hope of contributing toward this future goal, the paper then reviews the quantitative treatment of possible deviations via the Lie-admissible generalization of Lie's theory, with particular reference to the Lie-admissible generalizations of Lie group, Lie algebras, and enveloping associative algebras. A generalized notion of extended particle under nonlocal nonpotential strong interactions emerge from these studies. The theory is applied to the re-elaboration of the data on the spinor symmetry via neutron interferometers. It is shown that the data are indeed consistent with a breaking of the SU(2)-spin symmetry due to nonlocal nonpotential forces. A number of experiments for the future resolution of the issue are indicated
International Nuclear Information System (INIS)
Boreham, B. W.; Hora, H.
1997-01-01
We have recently developed a correspondence principle for electromagnetic interaction. When applied to laser interactions with electrons this correspondence principle identifies a critical laser intensity I*. This critical intensity is a transition intensity separating classical mechanical and quantum mechanical interaction regimes. In this paper we discuss the further application of I* to the interaction of bound electrons in atoms. By comparing I* with the ionisation threshold intensities as calculated from a cycle-averaged simple-atom model we conclude that I* can be usefully interpreted as a lower bound to the classical regime in studies of ionisation of gas atoms by intense laser beams
Kinetics of two-dimensional electron plasma, interacting with fluctuating potential
International Nuclear Information System (INIS)
Boiko, I.I.; Sirenko, Y.M.
1990-01-01
In this paper, from the first principles, after the fashion of Klimontovich, the authors derive quantum kinetic equation for electron gas, inhomogeneous in z-direction and homogeneous in XY-plane. Special attention is given to the systems with quasi-two-dimensional electron gas (2 DEG), which are widely explored now. Both interaction between the particles of 2 DEG (in general, of several sorts), and interaction with an external system (phonons, impurities, after change carries etc.) are considered. General theory is used to obtain energy and momentum balance equations and relaxation frequencies for 2 DEG in the basis of plane waves. The case of crossed electric and magnetic fields is also treated. As an illustration the problems of 2 DEG scattering on semibounded three-dimensional electron gas and on two-dimensional hole gas are considered; transverse conductivity of nondegenerate 2 DEG, scattered by impurities in ultraquantum magnetic field, is calculated
International Nuclear Information System (INIS)
Pashinkin, A.S.; Buketov, E.A.; Isabaeva, S.M.; Kasenov, B.K.
1985-01-01
The thermodynamic analysis of solid-phase reactions of alkali metal carbonates with arsenic pentoxide showing the possibility of formation of all arsenates at a higher than the room temperature is performed. Energetically most advantageous is formation of meta-arsenates. It is shown that temperature increase favours the reaction process. By Gibbs standard energy decrease the reactions form the Li>Na>K>Rb>Cs series. On the base of calculation data linear dependence of Gibbs standard energy in reactions on the atomic number of alkali metalis established. By the continuous weighing method the kinetics of interaction of alkali metal carbonates with arsenic pentoxide under isothermal conditions in the 450-500 deg C range is studied. Studies is the dependence of apparent energy of interaction of carbonates wih As 2 0 5 an atomic parameters of al
Directory of Open Access Journals (Sweden)
Hakuba Kitagawa
2016-07-01
Full Text Available The isolation and characterization of small sulfur allotropes have long remained unachievable because of their extreme lability. This study reports the first direct observation of disulfur (S2 with X-ray crystallography. Sulfur gas was kinetically trapped and frozen into the pores of two Cu-based porous coordination networks containing interactive iodide sites. Stabilization of S2 was achieved either through physisorption or chemisorption on iodide anions. One of the networks displayed shape selectivity for linear molecules only, therefore S2 was trapped and remained stable within the material at room temperature and higher. In the second network, however, the S2 molecules reacted further to produce bent-S3 species as the temperature was increased. Following the thermal evolution of the S2 species in this network using X-ray diffraction and Raman spectroscopy unveiled the generation of a new reaction intermediate never observed before, the cyclo-trisulfur dication (cyclo-S32+. It is envisaged that kinetic guest trapping in interactive crystalline porous networks will be a promising method to investigate transient chemical species.
Zhao, Bingwei; Wang, Xin; Yang, Xiaoyi
2015-12-01
Co-pyrolysis characteristics of Isochrysis (high lipid) and Chlorella (high protein) were investigated qualitatively and quantitatively based on DTG curves, biocrude yield and composition by individual pyrolysis and co-pyrolysis. DTG curves in co-pyrolysis have been compared accurately with those in individual pyrolysis. An interaction has been detected at 475-500°C in co-pyrolysis based on biocrude yields, and co-pyrolysis reaction mechanism appear three-dimensional diffusion in comparison with random nucleation followed by growth in individual pyrolysis based on kinetic analysis. There is no obvious difference in the maximum biocrude yields for individual pyrolysis and co-pyrolysis, but carboxylic acids (IC21) decreased and N-heterocyclic compounds (IC12) increased in co-pyrolysis. Simulation results of biocrude yield by Components Biofuel Model and Kinetics Biofuel Model indicate that the processes of co-pyrolysis comply with those of individual pyrolysis in solid phase by and large. Variation of percentage content in co-pyrolysis and individual pyrolysis biocrude indicated interaction in gas phase. Copyright © 2015. Published by Elsevier Ltd.
Uncovering new strong dynamics via topological interactions at the 100 TeV collider
DEFF Research Database (Denmark)
Molinaro, Emiliano; Sannino, Francesco; Thomsen, Anders Eller
2017-01-01
In models of composite Higgs dynamics, new composite pseudoscalars can interact with the Higgs and electroweak gauge bosons via anomalous interactions, stemming from the topological sector of the underlying theory. We show that a future 100 TeV proton-proton collider (FCC-pp) will be able to test...
Analysis of thermoluminescence kinetics of Mg2SiO4:Tb compounds employing an interactive model
International Nuclear Information System (INIS)
Marcazzo, J.; Prokic, M.; Santiago, M.; Molina, P.; Caselli, E.
2009-01-01
The kinetics involved in the thermoluminescence (TL) of Mg 2 SiO 4 :Tb compounds has been investigated by unfolding glow curves employing both the General Order model and a model that takes into account interactions among traps. The dependence of the glow curve shape on dose is only correctly described if interaction among traps is included in the analysis.
High-precision measurement of strong-interaction effects in pionic deuterium
Energy Technology Data Exchange (ETDEWEB)
Strauch, Thomas
2009-06-30
The hadronic ground state shift {epsilon}{sub 1s} and width {gamma}{sub 1s} in pionic deuterium were measured with high precision at the pion factory of the Paul Scherrer Institut (PSI), Switzerland (PSI-Experiment R-06.03). In this experiment the {pi}D(3p-1s) X-ray transition of about 3 keV was measured using a high-resolution Bragg crystal spectrometer equipped with a large-area position sensitive CCD detector. The characteristic X-radiation stems from a de-excitation cascade of the pionic atom. In order to produce an intense X-ray source, the cyclotron trap was used to stop pions in a cryogenic D{sub 2} target after winding up the pion beam in a magnetic field. The hadronic shift {epsilon}{sub 1s} is obtained from the measured transition energy by comparison to the pure electromagnetic value, where the determination of the broadening {gamma}{sub 1s} requires the precise knowledge of the spectrometer response, obtained from measurements of narrow X-ray transitions from highly ionised atoms, produced in an electron cyclotron resonance ion trap. As the formation rate is assumed to be density dependent, the {pi}D(3p-1s) X-ray energy was measured at three different D{sub 2} pressures. Another cascade process (Coulomb de-excitation) transforms the energy release of de-excitation steps into kinetic energy of the collision partners leading to a Doppler broadening of subsequent X-ray transitions. The hadronic broadening {gamma}{sub 1s} is only obtained after deconvolution of the spectrometer response function and the contributions from Doppler broadening. No energy dependence of the {pi}D(3p-1s) was found, and it is concluded that radiative de-excitation from molecular states is negligible within the experimental accuracy. Hence, the result for the shift reads {epsilon}{sub 1s} = (-2.325{+-}0.031) eV, corresponding to an accuracy of 1.3% and represents the average of the three measured densities. The uncertainty is dominated by the accuracy of the gallium K{alpha}{sub 2
High-precision measurement of strong-interaction effects in pionic deuterium
International Nuclear Information System (INIS)
Strauch, Thomas
2009-01-01
The hadronic ground state shift ε 1s and width Γ 1s in pionic deuterium were measured with high precision at the pion factory of the Paul Scherrer Institut (PSI), Switzerland (PSI-Experiment R-06.03). In this experiment the πD(3p-1s) X-ray transition of about 3 keV was measured using a high-resolution Bragg crystal spectrometer equipped with a large-area position sensitive CCD detector. The characteristic X-radiation stems from a de-excitation cascade of the pionic atom. In order to produce an intense X-ray source, the cyclotron trap was used to stop pions in a cryogenic D 2 target after winding up the pion beam in a magnetic field. The hadronic shift ε 1s is obtained from the measured transition energy by comparison to the pure electromagnetic value, where the determination of the broadening Γ 1s requires the precise knowledge of the spectrometer response, obtained from measurements of narrow X-ray transitions from highly ionised atoms, produced in an electron cyclotron resonance ion trap. As the formation rate is assumed to be density dependent, the πD(3p-1s) X-ray energy was measured at three different D 2 pressures. Another cascade process (Coulomb de-excitation) transforms the energy release of de-excitation steps into kinetic energy of the collision partners leading to a Doppler broadening of subsequent X-ray transitions. The hadronic broadening Γ 1s is only obtained after deconvolution of the spectrometer response function and the contributions from Doppler broadening. No energy dependence of the πD(3p-1s) was found, and it is concluded that radiative de-excitation from molecular states is negligible within the experimental accuracy. Hence, the result for the shift reads ε 1s = (-2.325±0.031) eV, corresponding to an accuracy of 1.3% and represents the average of the three measured densities. The uncertainty is dominated by the accuracy of the gallium Kα 2 transition used for the energy calibration. From the analysis of the Doppler broadening no
Energy Technology Data Exchange (ETDEWEB)
Ismail, I M.K.; Walker, P L
1979-01-01
In processes involving the hydrogasification of coal, the coal is first exposed to hydrogen at elevated temperatures and pressures during which devolatilization and gasification of the more reactive parts of the coal occur. A microporous coal char, which is relatively unreactive, is also produced. The char, in turn, can be reacted with steam to generate the hydrogen needed in the first part of the process. Or the char, in part, can be used in a boiler to raise steam. In any case, characterization of coal chars and the relation of character to behavior during gasification and/or combustion is important. This report is primarily concerned with laying the experimental base for the measurement of the heat of interaction of a gas (oxygen in this case) with chars. Following the laying of this base, using a char produced from a reproducible polymer system, heats of interaction of oxygen with chars produced from American coals, ranging in rank from anthracite to lignite, were measured. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were used to study the exothermicity and kinetics of interaction between Saran chars and oxygen at selected isothermal temperatures in the range 75 to 850/sup 0/C. The combination of measuring heats of oxygen interaction with chars (using the DSC technique) and weight changes during the interaction opens up a valuable new technique to characterize coal chars. Heats of interaction at 100/sup 0/C are found to be related to rates of char gasification at higher temperatures. Both heats of interaction and gasification rates are, in turn, seen to increase sharply as the rank of coal from which the char is produced is decreased.
Kamat, Vishal; Rafique, Ashique
2017-11-01
The Octet biosensors provide a high-throughput alternative to the well-established surface plasmon resonance (SPR) and SPR imaging (SPRi) biosensors to characterize antibody-antigen interactions. However, the utility of the Octet biosensors for accurate and reproducible measurement of binding rate constants of monoclonal antibodies (mAbs) is limited due to challenges such as analyte rebinding, and mass transport limitation (MTL). This study focuses on addressing these challenges and provides experimental conditions to reliably measure kinetics of mAb-antigen interactions. The mAb capture density of less than 0.6 nm was found to be optimal to measure a wide range of binding affinities on Octet HTX biosensor. The titration kinetic and single cycle kinetic assays performed on Octet HTX generated reproducible binding kinetic parameters and correlated with the values measured on Biacore 4000 and MASS-1. Kinetic assays performed on 0.1 nm density mAb surfaces significantly reduced MTL and enabled characterization of picomolar affinity mAbs. Finally, kinetic analysis performed on 150 antibodies to 10 antigens with molecular weights ranging from 21kD to 105kD showed concordance between Octet HTX, Biacore 4000 and MASS-1 (R 2 > 0.90). The data presented in this study suggest that under optimal experimental conditions, Octet biosensor is capable of generating kinetic values comparable to SPR/SPRi biosensors. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.
Scale-up of Λ3 : Massive gravity with a higher strong interaction scale
Gabadadze, Gregory
2017-10-01
Pure massive gravity is strongly coupled at a certain low scale, known as Λ3. I show that the theory can be embedded into another one, with new light degrees of freedom, to increase the strong scale to a significantly larger value. Certain universal aspects of the proposed mechanism are discussed, notably that the coupling of the longitudinal mode to a stress tensor is suppressed, thus making the linear theory consistent with the fifth-force exclusion. An example of the embedding theory studied in detail is five-dimensional anti-de Sitter massive gravity, with a large cosmological constant. In this example, the four-dimensional (4D) strong scale can be increased by 19 orders of magnitude. Holographic duality then suggests that the strong scale of the 4D massive gravity can be increased by coupling it to a 4D nonlocal conformal field theory, endowed with a UV cutoff; however, the five-dimensional classical gravity picture appears to be more tractable.
Veljković, Dušan Ž
2018-03-01
Energies of CH/O interactions between water molecule and polycyclic aromatic hydrocarbons with a different number of aromatic rings were calculated using ab initio calculations at MP2/cc-PVTZ level. Results show that an additional aromatic ring in structure of polycyclic aromatic hydrocarbons significantly strengthens CH/O interactions. Calculated interaction energies in optimized structures of the most stable tetracene/water complex is -2.27 kcal/mol, anthracene/water is -2.13 kcal/mol and naphthalene/water is -1.97 kcal/mol. These interactions are stronger than CH/O contacts in benzene/water complex (-1.44 kcal/mol) while CH/O contacts in tetracene/water complex are even stronger than CH/O contacts in pyridine/water complexes (-2.21 kcal/mol). Electrostatic potential maps for different polycyclic aromatic hydrocarbons were calculated and used to explain trends in the energies of interactions. Copyright © 2017 Elsevier Inc. All rights reserved.
Metal-insulator transition in SrIrO3 with strong spin-orbit interaction.
Wu, Fei-Xiang; Zhou, Jian; Zhang, L Y; Chen, Y B; Zhang, Shan-Tao; Gu, Zheng-Bin; Yao, Shu-Hua; Chen, Yan-Feng
2013-03-27
The thickness-dependent metal-insulator transition is observed in meta-stable orthorhombic SrIrO3 thin films synthesized by pulsed laser deposition. SrIrO3 films with thicknesses less than 3 nm demonstrate insulating behaviour, whereas those thicker than 4 nm exhibit metallic conductivity at high temperature, and insulating-like behaviour at low temperature. Weak/Anderson localization is mainly responsible for the observed thickness-dependent metal-insulator transition in SrIrO3 films. Temperature-dependent resistance fitting shows that electrical-conductivity carriers are mainly scattered by the electron-boson interaction rather than the electron-electron interaction. Analysis of the magneto-conductance proves that the spin-orbit interaction plays a crucial role in the magneto-conductance property of SrIrO3.
Strongly interacting vector bosons at the CERN LHC Quartic anomalous couplings
Belyaev, A; González-Garciá, M Concepción; Mizukoshi, J K; Novaes, S F; Zacharov, I E
1999-01-01
We analyze the potential of the CERN Large Hadron Collider to study anomalous quartic vector--boson interactions through the production of vector--boson pairs accompanied by jets. In the framework of $SU(2)_L \\otimes U(1)_Y$ chiral Lagrangians, we examine all effective operators of order $p^4$ that lead to new four--gauge--boson interactions but do not alter trilinear vertices. In our analyses, we perform the full tree level calculation of the processes leading to two jets plus vector--boson pairs, $W^+W^-$, $W^\\pm W^\\pm$, $W^\\pm Z$, or $ZZ$, taking properly into account the interference between the standard model and the anomalous contributions. We obtain the bounds that can be placed on the anomalous quartic interactions and we study the strategies to distinguish the possible new couplings.
A model-independent description of few-body system with strong interaction
International Nuclear Information System (INIS)
Simenog, I.V.
1985-01-01
In this contribution, the authors discuss the formulation of equations that provide model-independent description of systems of three and more nucleons irrespective of the details of the interaction, substantiate the approach, estimate the correction terms with respect to the force range, and give basic qualitative results obtained by means of the model-independent procedure. They consider three nucleons in the doublet state (spin S=I/2) taking into account only S-interaction. The elastic nd-scattering amplitude may be found from the model-independent equations that follow from the Faddeev equations in the short-range-force limit. They note that the solutions of several model-independent equations and basic results obtained with the use of this approach may serve both as a standard solution and starting point in the discussion of various conceptions concerning the details of nuclear interactions
The strong interaction at the collider and cosmic-rays frontiers
d'Enterria, David; Pierog, Tanguy; Ostapchenko, Sergey; Werner, Klaus
2012-01-01
First data on inclusive particle production measured in proton-proton collisions at the Large Hadron Collider (LHC) are compared to predictions of various hadron-interaction Monte Carlos (QGSJET, EPOS and SIBYLL) used commonly in high-energy cosmic-ray physics. While reasonable overall agreement is found for some of the models, none of them reproduces consistently the sqrt(s) evolution of all the measured observables. We discuss the implications of the new LHC data for the modeling of the non-perturbative and semihard parton dynamics in hadron-hadron and cosmic-rays interactions at the highest energies studied today.
Karakostas, Vassilios; Papadimitriou, Eleftheria; Jin, Xueshen; Liu, Zhihui; Paradisopoulou, Parthena; He, Zhang
2013-10-01
Northeast China, a densely populated area, is affected by intense seismic activity, which includes large events that caused extensive disaster and tremendous loss of life. For contributing to the continuous efforts for seismic hazard assessment, the earthquake potential from the active faults near the cities of Zhangjiakou and Langfang in Hebei Province is examined. We estimate the effect of the coseismic stress changes of strong (M ⩾ 5.0) earthquakes on the major regional active faults, and mapped Coulomb stress change onto these target faults. More importantly our calculations reveal that positive stress changes caused by the largest events of the 1976 Tangshan sequence make the Xiadian and part of Daxing fault, thus considered the most likely sites of the next strong earthquake in the study area. The accumulated static stress changes that reached a value of up to 0.4 bar onto these faults, were subsequently incorporated in earthquake probability estimates for the next 30 years.
Spectral asymptotics of a strong delta ' interaction on a planar loop
Czech Academy of Sciences Publication Activity Database
Exner, Pavel; Jex, M.
2013-01-01
Roč. 46, č. 34 (2013), s. 345201 ISSN 1751-8113 R&D Projects: GA ČR GAP203/11/0701 Institutional support: RVO:61389005 Keywords : Schrodinger operators * strong coupling asymptotics Subject RIV: BE - Theoretical Physics Impact factor: 1.687, year: 2013 http://iopscience.iop.org/1751-8121/46/34/345201/pdf/1751-8121_46_34_345201.pdf
Maria J. Lombardero; Matthew P. Ayres; Richard W. Hofstetter; John C. Moser; Kier D. Lepzig
2003-01-01
Phoretic mites of bark beetles are classic examples of commensal ectosymbionts. However, many such mites appear to have mutualisms with fungi that could themselves interact with beetles. We tested for indirect effects of phoretic mites on Dendroctonus frontalis, which auacks and kills pine trees in North America. Tarsonemus mites...
Numerical investigation into strong axis bending shear interaction in rolled I-shaped steel sections
Dekker, R.W.A.; Snijder, B.H.; Maljaars, J.
2016-01-01
Clause 6.2.8 of EN 1993-1-1 covers the design rules on bending-shear resistance, taking presence of shear into account by a reduced yield stress for the shear area. Numerical research on bending-shear interaction by means of the Abaqus Finite Element modelling soft-ware is presented. The numerical
Shantappa, A.; Hanagodimath, S. M.
2014-01-01
Effective atomic numbers, electron densities of some vitamins (Retinol, Riboflavin, Niacin, Biotin, Folic acid, Cobalamin, Phylloquinone and Flavonoids) composed of C, H, O, N, Co, P and S have been calculated for total and partial photon interactions by the direct method for energy range 1 keV-100 GeV by using WinXCOM and kinetic energy released in matter (Kerma) relative to air is calculated in energy range of 1 keV-20 MeV. Change in effective atomic number and electron density with energy is calculated for all photon interactions. Variation of photon mass attenuation coefficients with energy are shown graphically only for total photon interaction. It is observed that change in mass attenuation coefficient with composition of different chemicals is very large below 100 keV and moderate between 100 keV and 10 MeV and negligible above 10 MeV. Behaviour of vitamins is almost indistinguishable except biotin and cobalamin because of large range of atomic numbers from 1(H) to 16 (S) and 1(H) to 27(Co) respectively. K a value shows a peak due to the photoelectric effect around K-absorption edge of high- Z constituent of compound for biotin and cobalamin.
Energy Technology Data Exchange (ETDEWEB)
Lee, Seok Woo; /Stanford U., Geballe Lab.; Lee, Hyun-Wook; /Stanford U., Materials Sci. Dept.; Ryu, Ill; /Brown U.; Nix, William D.; /Stanford U., Materials Sci. Dept.; Gao, Huajian; /Brown U.; Cui, Yi; /Stanford U., Materials Sci. Dept. /SLAC
2015-06-01
Following an explosion of studies of silicon as a negative electrode for Li-ion batteries, the anomalous volumetric changes and fracture of lithiated single Si particles have attracted significant attention in various fields, including mechanics. However, in real batteries, lithiation occurs simultaneously in clusters of Si in a confined medium. Hence, understanding how the individual Si structures interact during lithiation in a closed space is necessary. Herein, we demonstrate physical/mechanical interactions of swelling Si structures during lithiation using well-defined Si nanopillar pairs. Ex situ SEM and in situ TEM studies reveal that compressive stresses change the reaction kinetics so that preferential lithiation occurs at free surfaces when the pillars are mechanically clamped. Such mechanical interactions enhance the fracture resistance of This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering, under Contract No. DE-AC02-76SF00515. SLAC-PUB-16300 2 lithiated Si by lessening the tensile stress concentrations in Si structures. This study will contribute to improved design of Si structures at the electrode level for high performance Li-ion batteries.
Wu, Ning; Feist, Johannes; Garcia-Vidal, Francisco J.
2016-11-01
We present a microscopic semianalytical theory for the description of organic molecules interacting strongly with a cavity mode. Exciton-vibration coupling within the molecule and exciton-cavity interaction are treated on an equal footing by employing a temperature-dependent variational approach. The interplay between strong exciton-vibration coupling and strong exciton-cavity coupling gives rise to a hybrid ground state, which we refer to as the lower polaron polariton. Explicit expressions for the ground-state wave function, the zero-temperature quasiparticle weight of the lower polaron polariton, the photoluminescence line strength, and the mean number of vibrational quanta are obtained in terms of the optimal variational parameters. The dependence of these quantities upon the exciton-cavity coupling strength reveals that strong cavity coupling leads to an enhanced vibrational dressing of the cavity mode, and at the same time a vibrational decoupling of the dark excitons, which in turn results in a lower polaron polariton resembling a single-mode dressed bare lower polariton in the strong-coupling regime. Thermal effects on several observables are briefly discussed.
International Nuclear Information System (INIS)
Biebel, O.
1993-11-01
A study of possible flavour dependence of the strong interaction is presented using data collected with the OPAL detector at the e + e - collider LEP. Four subsamples of events, highly enriched in bottom, charm, strange and light quarks are obtained from high momentum electrons and muons, D *± mesons, K s 0 mesons, and highly energetic stable charged particles, respectively. From the jet production rates of each of these four samples a strong coupling constant α s f for the dominant quark flavour is derived. The ratios of α s for a specific quark flavour f and its complementary flavours are determined to be α s b /α s udsc =1.017±0.036, α s c /α s udsb =0.918±0.115, α s s /α s udcb =1.158±0.164, α s uds /α s cb =1.038 ± 0.221, where the errors are combinations of statistical and systematic uncertainties. In combining the relevant data samples, a systematic study of possible dependence of the strong interaction on quark mass, weak isospin, and generation is performed. No evidence for any such dependence of the strong coupling constant α s is observed. Finally all samples are combined to determine the strong coupling constant of each flavour individually. Again the results are well consistent with the flavour independence of QCD. (orig.)
Strong electron-phonon interaction in the high-Tc superconductors: Evidence from the infrared
International Nuclear Information System (INIS)
Timusk, T.; Porter, C.D.; Tanner, D.B.
1991-01-01
We show that low-frequency structure in the infrared reflectance of the high-temperature superconductor YBa 2 Cu 3 O 7 results from the electron-phonon interaction. Characteristic antiresonant line shapes are seen in the phonon region of the spectrum and the frequency-dependent scattering rate of the mid-infrared electronic continuum has peaks at 150 cm -1 (19 meV) and at 360 cm -1 (45 meV) in good agreement with phonon density-of-states peaks in neutron time-of-flight spectra that develop in superconducting samples. The interaction between the phonons and the charge carriers can be understood in terms of a charged-phonon model
Application of the CIP Method to Strongly Nonlinear Wave-Body Interaction Problems
Zhu, Xinying
2006-01-01
Water entry and exit, green water on deck, sloshing in tanks and capsizing in intact and damaged conditions are examples on violent fluid motion. The combination of model tests, theoretical analysis and Computational Fluid Dynamics (CFD) methods is emphasized in treating these problems. Because mixing of air and liquid may occur, the interaction between the flow in the air and in the liquid ought to be considered in numerical simulations. Further, the mixing of air and liquid represents a sca...
On the starting process of strongly nonlinear vortex/Rayleigh-wave interactions
BROWN, P. G.; BROWN, S. N.; SMITH, F. T.; TIMOSHIN, S. N.
1993-01-01
An oncoming two-dimensional laminar boundary layer that develops an unstable inflection point and becomes three-dimensional is described by the Hall-Smith (1991) vortex/wave interaction equations. These equations are now examined in the neighbourhood of the position where the critical surface starts to form. A consistent structure is established in which an inviscid core flow is matched to a viscous buffer-layer solution where the appropriate jump condition on the transverse shear stress is s...
Second sound in a two-dimensional Bose gas: From the weakly to the strongly interacting regime
Ota, Miki; Stringari, Sandro
2018-03-01
Using Landau's theory of two-fluid hydrodynamics, we investigate first and second sounds propagating in a two-dimensional (2D) Bose gas. We study the temperature and interaction dependence of both sound modes and show that their behavior exhibits a deep qualitative change as the gas evolves from the weakly interacting to the strongly interacting regime. Special emphasis is placed on the jump of both sounds at the Berezinskii-Kosterlitz-Thouless transition, caused by the discontinuity of the superfluid density. We find that the excitation of second sound through a density perturbation becomes weaker and weaker as the interaction strength increases as a consequence of the decrease in the thermal expansion coefficient. Our results could be relevant for future experiments on the propagation of sound on the Bose-Einstein condensate (BEC) side of the BCS-BEC crossover of a 2D superfluid Fermi gas.
Bertini, Lorenzo; Cirillo, Emilio N. M.; Olivieri, Enzo
1999-12-01
In this paper we study a renormalization-group map: the block averaging transformation applied to Gibbs measures relative to a class of finite-range lattice gases, when suitable strong mixing conditions are satisfied. Using a block decimation procedure, cluster expansion, and detailed comparison between statistical ensembles, we are able to prove Gibbsianness and convergence to a trivial (i.e., Gaussian and product) fixed point. Our results apply to the 2D standard Ising model at any temperature above the critical one and arbitrary magnetic field.
CLEO-c and CESR-c: A new frontier in strong and weak interactions
Energy Technology Data Exchange (ETDEWEB)
Richichi, Stephen J
2003-06-01
We report on the physics potential of a charm and QCD factory, based on a proposal for the conversion of the existing CESR machine and CLEO detector: ''CESR-c and OLEO-c''. Such a facility will make major contributions to the field of quark flavor physics in this decade. It may also provide the best chance for understanding non-perturbative QCD, which is essential to understanding the strongly-coupled sectors of the new physics that lies beyond the Standard Model.
CLEO-c and CESR-c: A new frontier in strong and weak interactions
Richichi, Stephen J.
2003-06-01
We report on the physics potential of a charm and QCD factory, based on a proposal for the conversion of the existing CESR machine and CLEO detector: "CESR-c and OLEO-c". Such a facility will make major contributions to the field of quark flavor physics in this decade. It may also provide the best chance for understanding non-perturbative QCD, which is essential to understanding the strongly-coupled sectors of the new physics that lies beyond the Standard Model.
CLEO-c and CESR-c: A new frontier in strong and weak interactions
International Nuclear Information System (INIS)
Richichi, Stephen J.
2003-01-01
We report on the physics potential of a charm and QCD factory, based on a proposal for the conversion of the existing CESR machine and CLEO detector: ''CESR-c and OLEO-c''. Such a facility will make major contributions to the field of quark flavor physics in this decade. It may also provide the best chance for understanding non-perturbative QCD, which is essential to understanding the strongly-coupled sectors of the new physics that lies beyond the Standard Model
Energy Technology Data Exchange (ETDEWEB)
Quinn, John
2009-11-30
Work related to this project introduced the idea of an effective monopole strength Q* that acted as the effective angular momentum of the lowest shell of composite Fermions (CF). This allowed us to predict the angular momentum of the lowest band of energy states for any value of the applied magnetic field simply by determining N{sub QP} the number of quasielectrons (QE) or quasiholes (QH) in a partially filled CF shell and adding angular momenta of the N{sub QP} Fermions excitations. The approach reported treated the filled CF level as a vacuum state which could support QE and QH excitations. Numerical diagonalization of small systems allowed us to determine the angular momenta, the energy, and the pair interaction energies of these elementary excitations. The spectra of low energy states could then be evaluated in a Fermi liquid-like picture, treating the much smaller number of quasiparticles and their interactions instead of the larger system of N electrons with Coulomb interactions.
Guo, Dong; Heitman, Laura H; IJzerman, Adriaan P
2017-01-11
Ligand-receptor binding kinetics is an emerging topic in the drug research community. Over the past years, medicinal chemistry approaches from a kinetic perspective have been increasingly applied to G protein-coupled receptors including the adenosine receptors (AR), which are involved in a plethora of physiological and pathological conditions. The study of ligand-AR binding kinetics offers room for detailed structure-kinetics relationships next to more traditional structure-activity relationships. Their combination may facilitate the triage of candidate compounds in hit-to-lead campaigns. Furthermore, kinetic studies also help in understanding AR allosterism. Allosteric modulation may yield a change in the activity and conformation of a receptor resulting from the binding of a compound at a site distinct from where the endogenous agonist adenosine binds. Hence, in this Review, we summarize available data and evidence for the binding kinetics of orthosteric and allosteric AR ligands. We hope this Review will raise awareness to consider the kinetic aspects of drug-target interactions on both ARs and other drug targets.
Strong electromagnetic pulses generated in high-intensity laser-matter interactions
Rączka, P.; Dubois, J.-L.; Hulin, S.; Rosiński, M.; Zaraś-Szydłowska, A.; Badziak, J.
2018-01-01
Results are reported of an experiment performed at the Eclipse laser facility in CELIA, Bordeaux, on the generation of strong electromagnetic pulses. Measurements were performed of the target neutralization current, the total target charge and the tangential component of the magnetic field for the laser energies ranging from 45 mJ to 92 mJ with the pulse duration approximately 40 fs, and for the pulse durations ranging from 39 fs to 1000 fs, with the laser energy approximately 90 mJ. It was found that the values obtained for thick (mm scale) Cu targets are visibly higher than values reported in previous experiments, which is argued to be a manifestation of a strong dependence of the target electric polarization process on the laser contrast and hence on the amount of preplasma. It was also found that values obtained for thin (μm scale) Al foils were visibly higher than values for thick Cu targets, especially for pulse durations longer than 100 fs. The correlations between the total target charge versus the maximum value of the target neutralization current, and the maximum value of the tangential component of the magnetic field versus the total target charge were analysed. They were found to be in very good agreement with correlations seen in data from previous experiments, which provides a good consistency check on our experimental procedures.
DEFF Research Database (Denmark)
Wiuf, Carsten Henrik; Feliu, Elisenda
2013-01-01
is derived from the determinant of the Jacobian of the species formation rate function. Using this characterization, we further derive similar determinant criteria applicable to general sets of kinetics. The criteria are conceptually simple, computationally tractable, and easily implemented. Our approach...... embraces and extends previous work on multistationarity, such as work in relation to chemical reaction networks with dynamics defined by mass-action or noncatalytic kinetics, and also work based on graphical analysis of the interaction graph associated with the system. Further, we interpret the criteria...... and how the species influence each reaction. We characterize families of so-called power-law kinetics for which the associated species formation rate function is injective within each stoichiometric class and thus the network cannot exhibit multistationarity. The criterion for power-law kinetics...
Metastability and avalanche dynamics in strongly correlated gases with long-range interactions
Hruby, Lorenz; Dogra, Nishant; Landini, Manuele; Donner, Tobias; Esslinger, Tilman
2018-03-01
We experimentally study the stability of a bosonic Mott insulator against the formation of a density wave induced by long-range interactions and characterize the intrinsic dynamics between these two states. The Mott insulator is created in a quantum degenerate gas of 87-Rubidium atoms, trapped in a 3D optical lattice. The gas is located inside and globally coupled to an optical cavity. This causes interactions of global range, mediated by photons dispersively scattered between a transverse lattice and the cavity. The scattering comes with an atomic density modulation, which is measured by the photon flux leaking from the cavity. We initialize the system in a Mott-insulating state and then rapidly increase the global coupling strength. We observe that the system falls into either of two distinct final states. One is characterized by a low photon flux, signaling a Mott insulator, and the other is characterized by a high photon flux, which we associate with a density wave. Ramping the global coupling slowly, we observe a hysteresis loop between the two states—a further signature of metastability. A comparison with a theoretical model confirms that the metastability originates in the competition between short- and global-range interactions. From the increasing photon flux monitored during the switching process, we find that several thousand atoms tunnel to a neighboring site on the timescale of the single-particle dynamics. We argue that a density modulation, initially forming in the compressible surface of the trapped gas, triggers an avalanche tunneling process in the Mott-insulating region.
Li, Haoyuan
2017-05-18
Kinetic Monte Carlo (KMC) simulations have emerged as an important tool to help improve the efficiency of organic electronic devices by providing a better understanding of their device physics. In the KMC simulation of an organic device, the reliability of the results depends critically on the accuracy of the chosen charge-transfer rates, which are themselves strongly influenced by the site-energy differences. These site-energy differences include components coming from the electrostatic forces present in the system, which are often evaluated through electric potentials described by the Poisson equation. Here we show that the charge-carrier self-interaction errors that appear when evaluating the site-energy differences can lead to unreliable simulation results. To eliminate these errors, we propose two approaches that are also found to reduce the impact of finite-size effects. As a consequence, reliable results can be obtained at reduced computational costs. The proposed methodologies can be extended to other device simulation techniques as well.
Energy Technology Data Exchange (ETDEWEB)
Daily, Michael D.; Baer, Marcel D.; Mundy, Christopher J.
2016-03-10
The description of peptides and the use of molecular dynamics simulations to refine structures and investigate the dynamics on an atomistic scale are well developed. Through a consensus in this community over multiple decades, parameters were developed for molecular interactions that only require the sequence of amino-acids and an initial guess for the three-dimensional structure. The recent discovery of peptoids will require a retooling of the currently available interaction potentials in order to have the same level of confidence in the predicted structures and pathways as there is presently in the peptide counterparts. Here we present modeling of peptoids using a combination of ab initio molecular dynamics (AIMD) and atomistic resolution classical forcefield (FF) to span the relevant time and length scales. To properly account for the dominant forces that stabilize ordered structures of peptoids, namely steric-, electrostatic, and hydrophobic interactions mediated through sidechain-sidechain interactions in the FF model, those have to be first mapped out using high fidelity atomistic representations. A key feature here is not only to use gas phase quantum chemistry tools, but also account for solvation effects in the condensed phase through AIMD. One major challenge is to elucidate ion binding to charged or polar regions of the peptoid and its concomitant role in the creation of local order. Here, similar to proteins, a specific ion effect is observed suggesting that both the net charge and the precise chemical nature of the ion will need to be described. MDD was supported by MS3 (Materials Synthesis and Simulation Across Scales) Initiative at Pacific Northwest National Laboratory. Research was funded by the Laboratory Directed Research and Development program at Pacific Northwest National Laboratory. MDB acknowledges support from US Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Material & Engineering. CJM acknowledges
International Nuclear Information System (INIS)
Yu Zengqiang; Zhai Hui; Zhang Shizhong
2011-01-01
We study the properties of dilute bosons immersed in a single-component Fermi sea across a broad boson-fermion Feshbach resonance. The stability of the mixture requires that the bare interaction between bosons exceeds a critical value, which is a universal function of the boson-fermion scattering length, and exhibits a maximum in the unitary region. We calculate the quantum depletion, momentum distribution, and the boson contact parameter across the resonance. The transition from condensate to molecular Fermi gas is also discussed.
Energy Technology Data Exchange (ETDEWEB)
Schriber, Jeffrey B.; Evangelista, Francesco A. [Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322 (United States)
2016-04-28
We introduce a new procedure for iterative selection of determinant spaces capable of describing highly correlated systems. This adaptive configuration interaction (ACI) determines an optimal basis by an iterative procedure in which the determinant space is expanded and coarse grained until self-consistency. Two importance criteria control the selection process and tune the ACI to a user-defined level of accuracy. The ACI is shown to yield potential energy curves of N{sub 2} with nearly constant errors, and it predicts singlet-triplet splittings of acenes up to decacene that are in good agreement with the density matrix renormalization group.
Wan, Sijie; Peng, Jingsong; Li, Yuchen; Hu, Han; Jiang, Lei; Cheng, Qunfeng
2015-10-27
Graphene is the strongest and stiffest material, leading to the development of promising applications in many fields. However, the assembly of graphene nanosheets into macrosized nanocomposites for practical applications remains a challenge. Nacre in its natural form sets the "gold standard" for toughness and strength, which serves as a guide to the assembly of graphene nanosheets into high-performance nanocomposites. Here we show the strong, tough, conductive artificial nacre based on graphene oxide through synergistic interactions of hydrogen and covalent bonding. Tensile strength and toughness was 4 and 10 times higher, respectively, than that of natural nacre. The exceptional integrated strong and tough artificial nacre has promising applications in aerospace, artificial muscle, and tissue engineering, especially for flexible supercapacitor electrodes due to its high electrical conductivity. The use of synergistic interactions is a strategy for the development of high-performance nanocomposites.
Equilibration of a strongly interacting plasma: holographic analysis of local and nonlocal probes
Directory of Open Access Journals (Sweden)
Bellantuono Loredana
2016-01-01
Full Text Available The relaxation of a strongly coupled plasma towards the hydrodynamic regime is studied by analyzing the evolution of local and nonlocal observables in the holographic approach. The system is driven in an initial anisotropic and far-from equilibrium state through an impulsive time-dependent deformation (quench of the boundary spacetime geometry. Effective temperature and entropy density are related to the position and area of a black hole horizon, which has formed as a consequence of the distortion. The behavior of stress-energy tensor, equal-time correlation functions and Wilson loops of different shapes is examined, and a hierarchy among their thermalization times emerges: probes involving shorter length scales thermalize faster.
Nonlinear interaction of charged particles with strong laser pulses in a gaseous media
Directory of Open Access Journals (Sweden)
H. K. Avetissian
2007-07-01
Full Text Available The charged particles nonlinear dynamics in the field of a strong electromagnetic wave pulse of finite duration and certain form of the envelope, in the refractive medium with a constant and variable refraction indexes, is investigated by means of numerical integration of the classical relativistic equations of motion. The particle energy dependence on the pulse intensity manifests the nonlinear threshold phenomenon of a particle reflection and capture by actual laser pulses in dielectric-gaseous media that takes place for a plane electromagnetic wave in the induced Cherenkov process. Laser acceleration of the particles in the result of the reflection from the pulse envelope and in the capture regime with the variable refraction index along the pulse propagation direction is investigated.
Strongly coupled interaction between a ridge of fluid and an inviscid airflow
Paterson, C.
2015-07-01
© 2015 AIP Publishing LLC. The behaviour of a steady thin sessile or pendent ridge of fluid on an inclined planar substrate which is strongly coupled to the external pressure gradient arising from an inviscid airflow parallel to the substrate far from the ridge is described. When the substrate is nearly horizontal, a very wide ridge can be supported against gravity by capillary and/or external pressure forces; otherwise, only a narrower (but still wide) ridge can be supported. Classical thin-aerofoil theory is adapted to obtain the governing singular integro-differential equation for the profile of the ridge in each case. Attention is focused mainly on the case of a very wide sessile ridge. The effect of strengthening the airflow is to push a pinned ridge down near to its edges and to pull it up near to its middle. At a critical airflow strength, the upslope contact angle reaches the receding contact angle at which the upslope contact line de-pins, and continuing to increase the airflow strength beyond this critical value results in the de-pinned ridge becoming narrower, thicker, and closer to being symmetric in the limit of a strong airflow. The effect of tilting the substrate is to skew a pinned ridge in the downslope direction. Depending on the values of the advancing and receding contact angles, the ridge may first de-pin at either the upslope or the downslope contact line but, in general, eventually both contact lines de-pin. The special cases in which only one of the contact lines de-pins are also considered. It is also shown that the behaviour of a very wide pendent ridge is qualitatively similar to that of a very wide sessile ridge, while the important qualitative difference between the behaviour of a very wide ridge and a narrower ridge is that, in general, for the latter one or both of the contact lines may never de-pin.
Strong interaction between graphene layer and Fano resonance in terahertz metamaterials
Xiao, Shuyuan; Wang, Tao; Jiang, Xiaoyun; Yan, Xicheng; Cheng, Le; Wang, Boyun; Xu, Chen
2017-05-01
Graphene has emerged as a promising building block in modern optics and optoelectronics due to its novel optical and electrical properties. In the mid-infrared and terahertz (THz) regime, graphene behaves like metals and supports surface plasmon resonances (SPRs). Moreover, the continuously tunable conductivity of graphene enables active SPRs and gives rise to a range of active applications. However, the interaction between graphene and metal-based resonant metamaterials has not been fully understood. In this work, a simulation investigation on the interaction between the graphene layer and THz resonances supported by the two-gap split ring metamaterials is systematically conducted. The simulation results show that the graphene layer can substantially reduce the Fano resonance and even switch it off, while leaving the dipole resonance nearly unaffected, which is well explained with the high conductivity of graphene. With the manipulation of graphene conductivity via altering its Fermi energy or layer number, the amplitude of the Fano resonance can be modulated. The tunable Fano resonance here together with the underlying physical mechanism can be strategically important in designing active metal-graphene hybrid metamaterials. In addition, the ‘sensitivity’ to the graphene layer of the Fano resonance is also highly appreciated in the field of ultrasensitive sensing, where the novel physical mechanism can be employed in sensing other graphene-like two-dimensional materials or biomolecules with the high conductivity.
DEFF Research Database (Denmark)
Loft, N. J. S.; Marchukov, O. V.; Petrosyan, D.
2016-01-01
We have developed an efficient computational method to treat long, one-dimensional systems of strongly-interacting atoms forming self-assembled spin chains. Such systems can be used to realize many spin chain model Hamiltonians tunable by the external confining potential. As a concrete...... demonstration, we consider quantum state transfer in a Heisenberg spin chain and we show how to determine the confining potential in order to obtain nearly-perfect state transfer....
Directory of Open Access Journals (Sweden)
Jing Zhou
Full Text Available For adoptive cell transfer (ACT immunotherapy of tumor-reactive T cells, an effective therapeutic outcome depends upon cell dose, cell expansion in vivo through a minimally differentiated phenotype, long term persistence, and strong cytolytic effector function. An incomplete understanding of the biological coupling between T cell expansion, differentiation, and response to stimulation hinders the co-optimization of these factors. We report on a biophysical investigation of how the short-term kinetics of T cell functional activation, through molecular stimulation and cell-cell interactions, competes with phenotype differentiation. T cells receive molecular stimulation for a few minutes to a few hours in bulk culture. Following this priming period, the cells are then analyzed at the transcriptional level, or isolated as single cells, with continuing molecular stimulation, within microchambers for analysis via 11-plex secreted protein assays. We resolve a rapid feedback mechanism, promoted by T cell-T cell contact interactions, which strongly amplifies T cell functional performance while yielding only minimal phenotype differentiation. When tested in mouse models of ACT, optimally primed T cells lead to complete tumor eradication. A similar kinetic process is identified in CD8+ and CD4+ T cells collected from a patient with metastatic melanoma.
Li, S H; Jen, C P
2001-01-01
This work investigates the colloid-facilitated migration of radionuclides with radioactive decay in porous media. The sorption processes for radionuclides with both the solid matrix and colloids are treated as equilibrium or nonequilibrium. An analytical solution is obtained from a simplified linear equilibrium interaction mechanism. In addition, the adsorption processes for radionuclides with colloids and porous rock can be assumed as nonequilibrium and modeled by the linear kinetic adsorption. The numerical method is employed to solve the coupled colloid and radionuclide transport equations under nonequilibrium sorption assumption. Moreover, the reaction rates of the adsorption processes for radionuclides with the solid matrix and colloids affect the transport characteristics of radionuclides. The fast reaction rate of radionuclides with colloids causes a higher concentration of radionuclides adsorbed on colloids in a dispersed phase and enlarges acceleration caused by colloids. However, the fast reaction rate for radionuclides with solid matrix increases the retardation effect caused by the solid matrix. This work developed a predictive model for the transport of colloid-facilitated radionuclides in porous medium and to assess the importance of various phenomenological coefficients, particularly parameters for the adsorption interactions.
Strong electromagnetic pulses generated in laser-matter interactions with 10TW-class fs laser
Rączka, Piotr; Rosiński, Marcin; Zaraś-Szydłowska, Agnieszka; Wołowski, Jerzy; Badziak, Jan
2018-01-01
The results of an experiment on the generation of electromagnetic pulses (EMP) in the interaction of 10TW fs pulses with thick (mm scale) and thin foil (μm scale) targets are described. Such pulses, with frequencies in the GHz range, may pose a threat to safe and reliable operation of high-power, high-intensity laser facilities. The main point of the experiment is to investigate the fine temporal structure of such pulses using an oscilloscope capable of measurements at very high sampling rate. It is found that the amazing reproducibility of such pulses is confirmed at this high sampling rate. Furthermore, the differences between the EMP signals generated from thick and thin foil targets are clearly seen, which indicates that besides electric polarization of the target and the target neutralization current there may be other factors essential for the EMP emission.
Radio and X-Ray Observations of SN 2006jd: Another Strongly Interacting Type IIn Supernova
Chandra, Poonam; Chevalier, Roger A.; Chugai, Nikolai; Fransson, Claes; Irwin, Christopher M.; Soderberg, Alicia M.; Chakraborti, Sayan; Immler, Stefan
2012-01-01
We report four years of radio and X-ray monitoring of the Type IIn supernova SN 2006jd at radio wavelengths with the Very Large Array, Giant Metrewave Radio Telescope and Expanded Very Large Array at X-ray wavelengths with Chandra, XMM-Newton and Swift-XRT. We assume that the radio and X-ray emitting particles are produced by shock interaction with a dense circumstellar medium. The radio emission shows an initial rise that can be attributed to free-free absorption by cool gas mixed into the nonthermal emitting region external free-free absorption is disfavored because of the shape of the rising light curves and the low gas column density inferred along the line of sight to the emission region. The X-ray luminosity implies a preshock circumstellar density approximately 10(exp 6) per cubic meter at a radius r approximately 2 x 10(exp 16) centimeter, but the column density inferred from the photoabsorption of X-rays along the line of sight suggests a significantly lower density. The implication may be an asymmetry in the interaction. The X-ray spectrum shows Fe line emission at 6.9 keV that is stronger than is expected for the conditions in the X-ray emitting gas. We suggest that cool gas mixed into the hot gas plays a role in the line emission. Our radio and X-ray data both suggest the density profile is flatter than r2 because of the slow evolution of the unabsorbed emission.
DEFF Research Database (Denmark)
Jochumsen, Nicholas; Marvig, Rasmus Lykke; Pedersen, Søren Damkiær
2016-01-01
Colistin is an antimicrobial peptide that has become the only remaining alternative for the treatment of multidrug-resistant Gram-negative bacterial infections, but little is known of how clinical levels of colistin resistance evolve. We use in vitro experimental evolution and whole-genome sequen......Colistin is an antimicrobial peptide that has become the only remaining alternative for the treatment of multidrug-resistant Gram-negative bacterial infections, but little is known of how clinical levels of colistin resistance evolve. We use in vitro experimental evolution and whole......-genome sequencing of colistin-resistant Pseudomonas aeruginosa isolates from cystic fibrosis patients to reconstruct the molecular evolutionary pathways open for high-level colistin resistance. We show that the evolution of resistance is a complex, multistep process that requires mutation in at least five...... independent loci that synergistically create the phenotype. Strong intergenic epistasis limits the number of possible evolutionary pathways to resistance. Mutations in transcriptional regulators are essential for resistance evolution and function as nodes that potentiate further evolution towards higher...
Voltage-Controlled Switching of Strong Light-Matter Interactions using Liquid Crystals.
Hertzog, Manuel; Rudquist, Per; Hutchison, James A; George, Jino; Ebbesen, Thomas W; Börjesson, Karl
2017-12-22
We experimentally demonstrate a fine control over the coupling strength of vibrational light-matter hybrid states by controlling the orientation of a nematic liquid crystal. Through an external voltage, the liquid crystal is seamlessly switched between two orthogonal directions. Using these features, for the first time, we demonstrate electrical switching and increased Rabi splitting through transition dipole moment alignment. The C-N str vibration on the liquid crystal molecule is coupled to a cavity mode, and FT-IR is used to probe the formed vibropolaritonic states. A switching ratio of the Rabi splitting of 1.78 is demonstrated between the parallel and the perpendicular orientation. Furthermore, the orientational order increases the Rabi splitting by 41 % as compared to an isotropic liquid. Finally, by examining the influence of molecular alignment on the Rabi splitting, the scalar product used in theoretical modeling between light and matter in the strong coupling regime is verified. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
Inelastic strong interactions at high energies. Annual progress report, June 1, 1979-May 1, 1980
International Nuclear Information System (INIS)
Suranyi, P.
1980-02-01
Investigations in the area of Grand Unified Field Theories were begun. Various ways of breaking the SU(5) symmetric theory of Georgi and Glashow were studied. As usual, an approx. 24 of Higgs breaks the symmetry from SU(5) to SU(3)/sub c/xSU(2)xU(1). It was found that an approx. 45 of Higgs is acceptable for breaking the symmetry from SU(3)/sub c/xSU(2)xU(1) to SU(3)/sub c/xU(1)/sub em/. In addition phenomenologically correct quark-lepton mass ratios are obtained by use of renormalization-group techniques if there are 6 generations of particles in the theory. Efforts directed at the development of approximate methods for extracting information from quantum field theories were continued. The quantum mechanics of polynomial potentials as a model for quantum field theories was investigated. A perturbation expansion for the energy levels and wave functions was constructed and has been proven to be convergent for arbitrary values of the coupling constants, in contrast to ordinary perturbation expansions that have a zero radius of convergence. The physical significance of the new perturbation expansions was explored both in the weak and strong coupling limits
International Nuclear Information System (INIS)
Sherman, A.; Schreiber, M.
1995-01-01
We use the Eliashberg formalism for calculating T c in a model of cuprate perovskites with pairing mediated by both magnons and apex-oxygen vibrations. The influence of strong correlations on the energy spectrum is taken into account in the spin-wave approximation. It is shown that the hole-magnon interaction alone cannot yield high T c . But together with a moderate hole-phonon interaction it does lead to d-wave superconductivity at temperatures and hole concentrations observed in cuprates. High T c are connected with a large density of states due to extended Van Hove singularities, a conformity of the two interactions for the d symmetry, and high phonon frequencies
Powers, Lydia
The National Museum of Play at The Strong's Dancing Wings Butterfly Garden is a tropical rainforest that allows visitors to step into the world of butterflies, but lacks a more comprehensive educational element to teach visitors additional information about butterflies. Flutter-by Interactive Butterfly is a thesis project designed to enhance younger visitors' experience of the Dancing Wings Butterfly Garden with an interactive educational application that aligns with The Strong's mission of encouraging learning, creativity, and discovery. This was accomplished through a series of fun and educational games and animations, designed for use as a kiosk outside the garden and as a part of The Strong's website. Content, planning, and organization of this project has been completed through research and observation of the garden in the following areas: its visitors, butterflies, best usability practices for children, and game elements that educate and engage children. Flutter-by Interactive Butterfly teaches users about the butterfly's life cycle, anatomy, and characteristics as well as their life in the Dancing Wings Butterfly Garden. Through the use of the design programs Adobe Illustrator, Flash, and After Effects; the programming language ActionScript3.0; a child-friendly user interface and design; audio elements and user takeaways, Flutter-by Interactive Butterfly appeals to children of all ages, interests, and learning styles. The project can be viewed at lydiapowers.com/Thesis/FlutterByButterfly.html
Some issues linked to the description of systems in strong interaction
International Nuclear Information System (INIS)
Theussl, L.
2001-06-01
In the first part of this work we have dealt with some issues that are relevant in the area of nucleonic resonances within different constituent quark models. In this context we have concentrated on the theoretical description of Pi and Nu decays for N and Delta resonances. The results obtained point to the necessity of a more microscopic description of the dynamics which is at the same time responsible for the binding of quarks inside baryons and the decay of the latter ones. In the second part we have contributed to the study of crossed two-boson exchanges in the Bethe-Salpeter equation as well as to the investigation of different three-dimensional approaches that follow from the Bethe-Salpeter equation in a certain non-relativistic reduction scheme. These one include in particular an equation whose interaction depends on the total energy of the system. It was shown that such an equation is able to account for a certain number of properties of Bethe-Salpeter equation, in particular, that there also arise abnormal solutions in such an approach. (author)
Strong Hydrogen Bonded Molecular Interactions between Atmospheric Diamines and Sulfuric Acid.
Elm, Jonas; Jen, Coty N; Kurtén, Theo; Vehkamäki, Hanna
2016-05-26
We investigate the molecular interaction between methyl-substituted N,N,N',N'-ethylenediamines, propane-1,3-diamine, butane-1,4-diamine, and sulfuric acid using computational methods. Molecular structure of the diamines and their dimer clusters with sulfuric acid is studied using three density functional theory methods (PW91, M06-2X, and ωB97X-D) with the 6-31++G(d,p) basis set. A high level explicitly correlated CCSD(T)-F12a/VDZ-F12 method is used to obtain accurate binding energies. The reaction Gibbs free energies are evaluated and compared with values for reactions involving ammonia and atmospherically relevant monoamines (methylamine, dimethylamine, and trimethylamine). We find that the complex formation between sulfuric acid and the studied diamines provides similar or more favorable reaction free energies than dimethylamine. Diamines that contain one or more secondary amino groups are found to stabilize sulfuric acid complexes more efficiently. Elongating the carbon backbone from ethylenediamine to propane-1,3-diamine or butane-1,4-diamine further stabilizes the complex formation with sulfuric acid by up to 4.3 kcal/mol. Dimethyl-substituted butane-1,4-diamine yields a staggering formation free energy of -19.1 kcal/mol for the clustering with sulfuric acid, indicating that such diamines could potentially be a key species in the initial step in the formation of new particles. For studying larger clusters consisting of a diamine molecule with up to four sulfuric acid molecules, we benchmark and utilize a domain local pair natural orbital coupled cluster (DLPNO-CCSD(T)) method. We find that a single diamine is capable of efficiently stabilizing sulfuric acid clusters with up to four acid molecules, whereas monoamines such as dimethylamine are capable of stabilizing at most 2-3 sulfuric acid molecules.
Voskresenskaya, O O
2002-01-01
It is shown that the relations between probabilities of A_{2\\pi}-atoms creation in ns-states, derived with neglecting of strong interaction between pions, hold practically unchanged if the strong interaction is taken into account in the first order of perturbation theory. The formulation of Deser equation for the energy levels shift of the hadronic atoms (HA) is given in terms of effective range of strong interaction and relative correction to the coulombic wave function of HA at origin, caused by strong interaction.
Cirhin up-regulates a canonical NF-{kappa}B element through strong interaction with Cirip/HIVEP1
Energy Technology Data Exchange (ETDEWEB)
Yu, Bin; Mitchell, Grant A. [Genetique Medicale, Centre de Recherche CHU Sainte-Justine, Departement de Pediatrie, Universite de Montreal, Montreal, QC (Canada); Richter, Andrea, E-mail: andrea.richter@umontreal.ca [Genetique Medicale, Centre de Recherche CHU Sainte-Justine, Departement de Pediatrie, Universite de Montreal, Montreal, QC (Canada)
2009-11-01
North American Indian childhood cirrhosis (NAIC/CIRH1A) is a severe autosomal recessive intrahepatic cholestasis. All NAIC patients have a homozygous mutation in CIRH1A that changes conserved Arg565 to Trp (R565W) in Cirhin, a nucleolar protein of unknown function. Subcellular localization is unaffected by the mutation. Yeast two-hybrid screening identified Cirip (Cirhin interaction protein) and found that interaction between Cirip and R565W-Cirhin was weakened. Co-immunoprecipitation of the two proteins from nuclear extracts of HeLa cells strongly supports the yeast two hybrid results. Cirip has essentially the same sequence as the C-terminal of HIVEP1, a regulator of a canonical NF-{kappa}B sequence. Since Cirip has the zinc fingers required for this interaction, we developed an in vitro assay based on this element in mammalian cells to demonstrate functional Cirhin-Cirip interaction. The strong positive effect of Cirip on the NF-{kappa}B sequence was further increased by both Cirhin and R565W-Cirhin. Importantly, the effect of R565W-Cirhin was weaker than that of the wild type protein. We observed increased levels of Cirhin-Cirip complex in nuclear extracts in the presence of this NF-{kappa}B sequence. Our hypothesis is that Cirhin is a transcriptional regulatory factor of this NF-{kappa}B sequence and could be a participant in the regulation of other genes with NF-{kappa}B responsive elements. Since the activities of genes regulated through NF-{kappa}B responsive elements are especially important during development, this interaction may be a key to explain the perinatal appearance of NAIC.
Czech Academy of Sciences Publication Activity Database
Sauvan, P.; Dalimier, E.; Riconda, C.; Oks, E.; Renner, Oldřich; Weber, S.
2010-01-01
Roč. 1, č. 2 (2010), s. 123-128 ISSN 2229-3159 R&D Projects: GA MŠk(CZ) LC528 Institutional research plan: CEZ:AV0Z10100523 Keywords : laser-plasma interaction * PIC plasma model ing * strong quasimonochromatic electric fields * x-ray line broadening * stark effect * floquet theory Subject RIV: BH - Optics, Masers, Lasers http://www.auburn.edu/academic/cosam/departments/physics/iramp/1_2/sauvan_et_al.pdf
International Nuclear Information System (INIS)
Lundberg, Pernilla; Koskinen, Cecilia; Baldock, Paul A.; Loethgren, Hanna; Stenberg, Asa; Lerner, Ulf H.; Oldenborg, Per-Arne
2007-01-01
Physical interaction between the cell surface receptors CD47 and signal regulatory protein alpha (SIRPα) was reported to regulate cell migration, phagocytosis, cytokine production, and macrophage fusion. However, it is unclear if the CD47/SIRPα-interaction can also regulate macrophage colony-stimulating factor (M-CSF) and receptor activator of nuclear factor (NF)-κB ligand (RANKL)-stimulated formation of osteoclasts. Here, we show that functional blocking antibodies to either CD47 or SIRPα strongly reduced formation of multinucleated tartrate-resistant acid phosphatase (TRAP) + osteoclasts in cultures of murine hematopoietic cells, stimulated in vitro by M-CSF and RANKL. In addition, the numbers of osteoclasts formed in M-CSF/RANKL-stimulated bone marrow macrophage cultures from CD47 -/- mice were strongly reduced, and bones of CD47 -/- mice exhibited significantly reduced osteoclast numbers, as compared with wild-type controls. We conclude that the CD47/SIRPα interaction is important for M-CSF/RANKL-stimulated osteoclast formation both in vivo and in vitro, and that absence of CD47 results in decreased numbers of osteoclasts in CD47 -/- mice
Brito, Paula M.; Antunes, Fernando
2014-01-01
The lack of kinetic data concerning the biological effects of reactive oxygen species is slowing down the development of the field of redox signaling. Herein, we deduced and applied equations to estimate kinetic parameters from typical redox signaling experiments. H2O2-sensing mediated by the oxidation of a protein target and the switch-off of this sensor, by being converted back to its reduced form, are the two processes for which kinetic parameters are determined. The experimental data requ...
Jovian Plasma Torus Interaction with Europa: 3D Hybrid Kinetic Simulation. First results
Lipatov, A. S.; Cooper, J. F.; Paterson, W. R.; Sittler, E. C.; Hartle, R. E.; Simpson, D. G.
2010-01-01
The hybrid kinetic model supports comprehensive simulation of the interaction between different spatial and energetic elements of the Europa-moon-magnetosphere system with respect to variable upstream magnetic field and flux or density distributions of plasma and energetic ions, electrons, and neutral atoms. This capability is critical for improving the interpretation of the existing Europa flyby measurements from the Galileo orbiter mission, and for planning flyby and orbital measurements, (including the surface and atmospheric compositions) for future missions. The simulations are based on recent models of the atmosphere of Europa (Cassidy etal.,2007;Shematovichetal.,2005). In contrast to previous approaches with MHD simulations, the hybrid model allows us to fully take into account the finite gyro radius effect and electron pressure, and to correctly estimate the ion velocity distribution and the fluxes along the magnetic field (assuming an initial Maxwellian velocity distribution for upstream background ions).Non-thermal distributions of upstream plasma will be addressed in future work. Photoionization,electron-impact ionization, charge exchange and collisions between the ions and neutrals are also included in our model. We consider two models for background plasma:(a) with O(++) ions; (b) with O(++) and S(++) ions. The majority of O2 atmosphere is thermal with an extended cold population (Cassidyetal.,2007). A few first simulations already include an induced magnetic dipole; however, several important effects of induced magnetic fields arising from oceanic shell conductivity will be addressed in later work.
Non-additive non-interacting kinetic energy of rare gas dimers.
Jiang, Kaili; Nafziger, Jonathan; Wasserman, Adam
2018-03-14
Approximations of the non-additive non-interacting kinetic energy (NAKE) as an explicit functional of the density are the basis of several electronic structure methods that provide improved computational efficiency over standard Kohn-Sham calculations. However, within most fragment-based formalisms, there is no unique exact NAKE, making it difficult to develop general, robust approximations for it. When adjustments are made to the embedding formalisms to guarantee uniqueness, approximate functionals may be more meaningfully compared to the exact unique NAKE. We use numerically accurate inversions to study the exact NAKE of several rare-gas dimers within partition density functional theory, a method that provides the uniqueness for the exact NAKE. We find that the NAKE decreases nearly exponentially with atomic separation for the rare-gas dimers. We compute the logarithmic derivative of the NAKE with respect to the bond length for our numerically accurate inversions as well as for several approximate NAKE functionals. We show that standard approximate NAKE functionals do not reproduce the correct behavior for this logarithmic derivative and propose two new NAKE functionals that do. The first of these is based on a re-parametrization of a conjoint Perdew-Burke-Ernzerhof (PBE) functional. The second is a simple, physically motivated non-decomposable NAKE functional that matches the asymptotic decay constant without fitting.
Zhao, Yuanyuan; Jiang, Guoliang; Hu, Jiandong; Hu, Fengjiang; Wei, Jianguang; Shi, Liang
2010-10-01
In the immunology, there are two important types of biomolecular interaction: antigens-antibodies and receptors-ligands. Monitoring the response rate and affinity of biomolecular interaction can help analyze the protein function, drug discover, genomics and proteomics research. Moreover the association rate constant and dissociation rate constant of receptors-ligands are the important parameters for the study of signal transmission between cells. Recent advances in bioanalyzer instruments have greatly simplified the measurement of the kinetics of molecular interactions. Non-destructive and real-time monitoring the response to evaluate the parameters between antigens and antibodies can be performed by using optical surface plasmon resonance (SPR) biosensor technology. This technology provides a quantitative analysis that is carried out rapidly with label-free high-throughput detection using the binding curves of antigens-antibodies. Consequently, the kinetic parameters of interaction between antigens and antibodies can be obtained. This article presents a low cost integrated SPR-based bioanalyzer (HPSPR-6000) designed by ourselves. This bioanalyzer is mainly composed of a biosensor TSPR1K23, a touch-screen monitor, a microprocessor PIC24F128, a microflow cell with three channels, a clamp and a photoelectric conversion device. To obtain the kinetic parameters, sensorgrams may be modeled using one of several binding models provided with BIAevaluation software 3.0, SensiQ or Autolab. This allows calculation of the association rate constant (ka) and the dissociation rate constant (kd). The ratio of ka to kd can be used to estimate the equilibrium constant. Another kind is the analysis software OriginPro, which can process the obtained data by nonlinear fitting and then get some correlative parameters, but it can't be embedded into the bioanalyzer, so the bioanalyzer don't support the use of OriginPro. This paper proposes a novel method to evaluate the kinetic parameters
Huang, Haoliang; Huang, Junying; Liu, Weipeng; Fang, Yueping; Liu, Yingju
2017-11-15
As one of the most promising Pt alternatives for cost-effective hydrogen production, molybdenum disulfide (MoS 2 ), although has been studied extensively to improve its electrocatalytic activity, suffers from scarce active sites, low conductivity, and lack of interaction with substrates. To this end, we anchor ultradispersed and single-layered MoS 2 nanoflakes on graphene sheets via a hybrid intermediate (MoO x -cysteine-graphene oxide), which not only confines the subsequent growth of MoS 2 on the graphene surface but also ensures the intimate interaction between Mo species and graphene at the initial stage. Mo-O-C bond and a possible residual MoO 3-x layer are proposed to comprise the interface bridging the two inherent incompatible phases, MoS 2 and graphene. This strongly coupled structure together with the highly exposed MoS 2 morphology accelerates the electron injection from graphene to the active sites of MoS 2 , and thus the hydrogen evolution reaction (HER) can achieve an overpotential of ∼275 mV at ∼-740 mA cm -2 , and a Pt-like Tafel slope of ∼35 mV dec -1 . Our results shed light on the indispensable role of interfacial interaction within semiconducting material-nanocarbon composites and provide a new insight into the actual activity of MoS 2 toward the HER.
Probing Sub-GeV Mass Strongly Interacting Dark Matter with a Low-Threshold Surface Experiment.
Davis, Jonathan H
2017-11-24
Using data from the ν-cleus detector, based on the surface of Earth, we place constraints on dark matter in the form of strongly interacting massive particles (SIMPs) which interact with nucleons via nuclear-scale cross sections. For large SIMP-nucleon cross sections, the sensitivity of traditional direct dark matter searches using underground experiments is limited by the energy loss experienced by SIMPs, due to scattering with the rock overburden and experimental shielding on their way to the detector apparatus. Hence, a surface-based experiment is ideal for a SIMP search, despite the much larger background resulting from the lack of shielding. We show using data from a recent surface run of a low-threshold cryogenic detector that values of the SIMP-nucleon cross section up to approximately 10^{-27} cm^{2} can be excluded for SIMPs with masses above 100 MeV.
Energy Technology Data Exchange (ETDEWEB)
Burbery, N.J. [Department of Mechanical Engineering, University of Auckland, Auckland 1010 (New Zealand); Das, R., E-mail: r.das@auckland.ac.nz [Department of Mechanical Engineering, University of Auckland, Auckland 1010 (New Zealand); Ferguson, W.G. [Department of Chemical and Materials Engineering, University of Auckland, Auckland 1010 (New Zealand)
2016-08-15
Grain boundaries (GBs) provide a source and/or a sink for crystal defects and store elastic energy due to the non-uniform atomic bonding structure of the GB core. GB structures are thermodynamically driven to transition to the lowest energy configuration possible; however to date there has been little evidence to explain why specific GB structures have a low energy state. Furthermore, there is little quantitative demonstration of the significance of physical and GB structure characteristics on the GB energy, thermal stability, and the effect of temporary local GB structure transformations on defect interactions. This paper evaluates the defect interactions and structure stability of multiple Σ5(310) GB structures in bi-crystals of pure aluminium, and systematically investigates the features at 0 K to characterise multiple metastable structures. Structure stability is evaluated by utilising unstable vacancy defects to initiate GB transformations, and using nudged elastic band simulations to quantify this with the activation energy. The emission of stable vacancy defects from the ‘stable’ and metastable grain boundaries is also evaluated in the same manner. A detailed analysis of dislocation nucleation at the atomistic scale demonstrates that local transformations of GB structure between stable and metastable intermediates can provide a mechanism to accommodate the generation of crystal defects. Kinetic (time-dependent) effects that compete with energetic driving forces for structural transformations of GBs are shown to cause a significant effect on the activation properties that may exceed the influence of GB potential energy. The results demonstrate that GB structural multiplicity can be associated with the generation and absorption of dislocations and vacancies. This paper demonstrates the suitability of atomistic simulations coupled with nudged elastic band simulations to evaluate fundamental thermodynamic properties of pure FCC metals. Overall, this paper
Strong interactions - quark models
International Nuclear Information System (INIS)
Goto, M.; Ferreira, P.L.
1979-01-01
The variational method is used for the PSI and upsilon family spectra reproduction from the quark model, through several phenomenological potentials, viz.: linear, linear plus coulomb term and logarithmic. (L.C.) [pt
International Nuclear Information System (INIS)
Vugman, N.V.
1973-08-01
The radiation effects in ]Ir III (CN) 6 ] 3- diamagnetic complexe inserted in the KCl lattice and irradiated with electrons of 2MeV by electron spin resonance (ESR) are analysed. Formulas for g and A tensors in the ligand field approximation, are derivated to calculate non coupling electron density in the metal. The X polarization field of inner shells is positive, indicating a 6s function mixture in the non coupling electron molecular orbital. The observed hyperfine structure is assigned to 4 equivalent nitrogen and one non equivalent nitrogen. This hypothesis is verified by experience of isotope substitution with 15 N. The s and p spin density in ligands are calculated and discussed in terms of molecular obitals. The effects of strong quadrupole interaction into the EPR spectra of ]Ir II (CN) 5 ] 3- complex are analysed by MAGNSPEC computer program to diagonalize the Spin Hamiltonian of the system. Empiric rules for EPR espectrum interpretation with strong quadrupole interaction. A review of EPR technique and a review of main concepts of crystal-field and ligand field theories, are also presented. (M.C.K.) [pt
Han, Lin; Fang, Chun; Zhu, Ruixue; Peng, Qiang; Li, Ding; Wang, Min
2017-02-01
As the aglycone of phloridzin, phloretin belongs to dihydrochalcone with antioxidant, anti-inflammatory and antimicrobial activities. In this study, multispectroscopic techniques and molecular docking analysis were used to investigate the inhibitory activity and mechanisms of phloretin on α-glucosidase. The results showed that phloretin reversibly inhibited α-glucosidase in a mixed-type manner and the value of IC 50 was 31.26μgL -1 . The intrinsic fluorescence of α-glucosidase was quenched by the interactions with phloretin through a static quenching mechanism and spontaneously formed phloretin-α-glucosidase complex by the driving forces of van der Waals force and hydrogen bond. Atomic force microscope (AFM) studies and FT-IR measurements suggested that the interactions could change the micro-environments and conformation of the enzymes and the molecular docking analysis displayed the exact binding site of phloretin on α-glucosidase. These results indicated that phloretin is a strong α-glucosidase inhibitor, thus could be contribute to the improvement of diabetes mellitus. Copyright © 2016 Elsevier B.V. All rights reserved.
Guo, Zhen; Wu, Fei; Singh, Vikramjeet; Guo, Tao; Ren, Xiaohong; Yin, Xianzhen; Shao, Qun; York, Peter; Patterson, Laurence H; Zhang, Jiwen
2017-06-05
Cyclodextrins (CD) are widely used bitter taste masking agents, for which the binding equilibrium constant (K) for the drug-CD complex is a conventional parameter for quantitating the taste masking effects. However, some exceptions have been reported to the expected relationship between K and bitterness reduction and the relationship between kinetic parameters of a drug-CD interaction, including association rate constant (K a ) and disassociation rate constant (K d ), and taste masking remains unexplored. In this study, based upon a database of kinetic parameters of drugs-HP-β-CD generated by Surface Plasmon Resonance Imaging for 485 drugs, the host-guest kinetic interactions between drugs and HP-β-CD for prediction of taste masking effects have been investigated. The taste masking effects of HP-β-CD for 13 bitter drugs were quantitatively determined using an electronic gustatory system (α-Astree e-Tongue). Statistical software was used to establish a model based on Euclidean distance measurements, K a and K d of the bitter drugs/HP-β-CD-complexes (R 2 =0.96 and Pkinetics of drug-CD interactions and taste masking was established and providing a new strategy for predicting the cyclodextrin mediated bitter taste masking. Copyright © 2017 Elsevier B.V. All rights reserved.
Miao, Yuxuan; Zhou, Jia; Chen, Cuicui; Shen, Delong; Song, Wei; Feng, Yongjun
2008-12-01
Pantoea (formerly Enterobacter) agglomerans YS19 is a dominant diazotrophic endophyte isolated from rice (Oryza sativa cv. Yuefu) grown in a temperate-climate region in west Beijing, China. In vitro adsorption and invasion of YS19 on host plant root were studied in this research. Adsorption of YS19 on rice seedling roots closely resembled the Langmuir adsorption and showed a higher adsorption quantity than the control strains Paenibacillus polymyxa WY110 (a rhizospheric bacterium from the same rice cultivar) and Escherichia coli HB101 (a general model bacterium). Adsorption dynamics study revealed high rates and a long duration of the YS19-rice root adsorption process. Adsorption of YS19 was mainly observed on the root hair, though which it enters the plant. This in vitro adsorption study revealed an apparent strong interaction between YS19 and rice at the early endophyte-host recognition stage.
Measurement of the strong-interaction shift and broadening of the ground state of the panti p atom
International Nuclear Information System (INIS)
Ziegler, M.; Duch, K.D.; Heel, M.; Kalinowsky, H.; Kayser, F.; Klempt, E.; Rieger, R.; Schreiber, O.; Straumann, U.; Weidenauer, P.; Ahmad, S.; Comyn, M.; Armenteros, R.; Bailey, D.; Barlag, S.; Gastaldi, U.; Landua, R.; Auld, E.G.; Axen, D.A.; Erdman, K.L.; Howard, B.; Howard, R.; White, B.L.; Beer, G.A.; Marshall, G.M.; Robertson, L.P.; Bizot, J.C.; Delcourt, B.; Jeanjean, J.; Nguyen, H.; Dahme, W.; Feld-Dahme, F.; Schaefer, U.; Wodrich, W.R.; Prevot, N.; Sabev, C.
1988-01-01
The K α X-rays from panti p atoms formed in H 2 gas at normal temperature and pressure are unambiguously identified by coincidences with L X-rays populating the 2P level. Background due to inner bremsstrahlung is suppressed by selecting events annihilating into neutral final states only. The K α line is observed with a significance of more than 25 standard deviations at an energy of 8.67(15) keV. From fits to the K α line we obtain a strong-interaction shift and width of the 1S level, averaged over the unresolved spin singlet and triplet contributions, of ΔE + iΓ/2 = [-0.70(15) + i0.80(2)] keV. (orig.)
Indian Academy of Sciences (India)
Collapse of a Bose gas: Kinetic approach ... Thermodynamical, statistical and static properties of condensates; Ultracold and trapped gases; matter waves. ... of a harmonically trapped attractively interacting Bose gas below the condensation point by introducing a kinetic approach within the Hartee-Fock approximation.
Tarun, E I; Savenkova, M I; Metelitsa, D I
1995-07-01
Using solid phase enzyme-linked immunoassay (ELISA), rate constants for the formation and dissociation as well as equilibrium dissociation constants for strophanthin complexes interaction with specific antibodies (both soluble and immobilized on activated polystyrene beads and polyamide membranes) have been determined. A satisfactory correlation was found between dissociation constants for immune complexes determined by ELISA (both soluble and immobilized ones) and associations constants for these complexes determined by the Scatchard method. The experimental values of kinetic and equilibrium constants for strophanthin K and its peroxidase complexes interaction reflect the difference in the nature of interacting particles and their environment. Strophanthin complexes with antibodies appeared to be more stable when formed on adsorbents (in comparison with those formed in solution). Strophanthin interaction with immobilized antibodies occurred at a slower rate than that with soluble antibodies. Strophanthin reacts with antibodies more readily than its complexes both in solution and on solid matrices of various polymeric nature.
Bondza, Sina; Stenberg, Jonas; Nestor, Marika; Andersson, Karl; Björkelund, Hanna
2014-11-03
Antibody-drug conjugates (ADC) have shown promising effects in cancer therapy by combining the target specificity of an antibody with the toxicity of a chemotherapeutic drug. As the number of therapeutic antibodies is significantly larger than those used as ADCs, there is unused potential for more effective therapies. However, the conjugation of an additional molecule to an antibody may affect the interaction with its target, altering association rate, dissociation rate, or both. Any changes of the binding kinetics can have subsequent effects on the efficacy of the ADCs, thus the kinetics are important to monitor during ADC development and production. This paper describes a method for the analysis of conjugation effects on antibody binding to its antigen, using the instrument LigandTracer and a fluorescent monovalent anti-IgG binder denoted FIBA, which did not affect the interaction. All measurements were done in real time using living cells which naturally expressed the antigens. With this method the binding profiles of different conjugations of the therapeutic anti-EGFR antibody cetuximab and the anti-CD44v6 antibody fragment AbD15171 were evaluated and compared. Even comparatively small modifications of cetuximab altered the interaction with the epidermal growth factor receptor (EGFR). In contrast, no impact on the AbD15171-CD44v6 interaction was observed upon conjugation. This illustrates the importance to study the binding profile for each ADC combination, as it is difficult to draw any general conclusion about conjugation effects. The modification of interaction kinetics through conjugation opens up new possibilities when optimizing an antibody or an ADC, since the conjugations can be used to create a binding profile more apt for a specific clinical need.
International Nuclear Information System (INIS)
Senda Ikuo.
1991-05-01
We propose dynamical models of hadrons, the nucleation model and the free-decay model, in which results of string model are used to represent interactions. The dynamical properties of hadrons, which are obtained by string model, are examined and their parameters are fitted by experimental data. The equilibrium properties of hadrons at high density are investigated by the nucleation model and we found a singular behaviour at energy density 3 ∼ 5 GeV/fm 3 , where hadrons coalesce to create highly excited states. We argue that this singular behaviour corresponds to the phase transition to quark-gluon plasma. The possibility to observe the production of high density strongly interacting matter at collider experiments are discussed using the free-decay model, which produces pion distributions as decay products of resonances. We show that our free-decay model recovers features of hadron distributions obtained in hadron collision experiments. Finally the perspectives and extensions are discussed. (author). 34 refs, 19 figs, 2 tabs
Kinetic description of the interaction between energetic particles and waves in fusion plasmas
International Nuclear Information System (INIS)
Zarzoso, D.
2012-09-01
The impact of energetic particle transport on turbulence has been so far little explored and constitutes the main focus of this thesis. We investigate two critical issues: (1) the properties of one of the generation mechanisms of energetic particles and (2) the impact of energetic particles on turbulence. The generation of energetic particles is studied in ICRH discharges. We quantify the energetic particle kinetic effects on the discharge properties. For this purpose, we introduce the velocity anisotropy, which is essential to model ICRH scenarios, characterized by perpendicular heating rather than parallel. This is done by means of a full-wave 3D solver called EVE coupled to a module called AQL. This module solves the Fokker-Planck equation in both parallel and perpendicular directions in velocity space. The coupling EVE-AQL provides the self-consistent response of the plasma. The importance of the anisotropy is evidenced by the formation of a long tail in the distribution function for high perpendicular velocities, modifying the properties of the discharge. The impact of energetic particles on electrostatic turbulence is evidenced by means of the full-f 5D gyrokinetic GYSELA code. This is done in two steps. First, the excitation of a particular class of energetic modes in the acoustic range of frequency (EGAMs) is demonstrated. We predict a theoretical linear threshold for the excitation of EGAMs that is verified numerically in neoclassical GYSELA simulations. In addition, the structure of the distribution function is found to impact the excitation and saturation of the modes. Second, EGAMs are excited for the first time in global, full-f and flux-driven turbulent simulations. For this purpose, a heating source is implemented in GYSELA. The effects of this source on turbulence are predicted analytically and corroborated numerically, in particular the possibility of turbulence suppression. In the simulations presented in this thesis, EGAMs are found to interact
Effects of strong interactions between Ti and ceria on the structures of Ti/CeO2.
Yao, Xiao-Dan; Zhu, Kong-Jie; Teng, Bo-Tao; Yu, Cao-Ming; Zhang, Yun-Lei; Liu, Ya; Fan, Maohong; Wen, Xiao-Dong
2016-11-30
The effects of strong interactions between Ti and ceria on the structures of Ti/CeO 2 (111) are systematically investigated by density functional theory calculation. To our best knowledge, the adsorption energy of a Ti atom at the hollow site of CeO 2 is the highest value (-7.99 eV) reported in the literature compared with those of Au (-0.88--1.26 eV), Ag (-1.42 eV), Cu (-2.69 eV), Pd (-1.75 eV), Pt (-2.62 eV) and Sn (-3.68 eV). It is very interesting to find that Ti adatoms disperse at the hollow site of CeO 2 (111) to form surface TiO x species, instead of aggregating to form Ti metal clusters for the Ti-CeO 2 interactions that are much stronger than those of Ti-Ti ones. Ti adatoms are completely oxidized to Ti 4+ ions if they are monatomically dispersed on the next near hollow sites of CeO 2 (111) (xTi-NN-hollow); while Ti 3+ ions are observed when they locate at the near hollow sites (xTi-N-hollow). Due to the electronic repulsive effects among Ti 3+ ions, the adsorption energies of xTi-N-hollow are slightly weaker than those of xTi-NN-hollow. Simultaneously, the existence of unstable Ti 3+ ions on xTi-N-hollow also leads to the restructuring of xTi-N-hollow by surface O atoms of ceria transferring to the top of Ti 3+ ions, or oxidation by O 2 adsorption and dissociation. Both processes improve the stability of the xTi/CeO 2 system by Ti 3+ oxidation. Correspondingly, surface TiO 2 -like species form. This work sheds light into the structures of metal/CeO 2 catalysts with strong interactions between the metal and the ceria support.
You, Benoit; Colomban, Olivier; Heywood, Mark; Lee, Chee; Davy, Margaret; Reed, Nicholas; Pignata, Sandro; Varsellona, Nenzi; Emons, Günter; Rehman, Khalid; Steffensen, Karina Dahl; Reinthaller, Alexander; Pujade-Lauraine, Eric; Oza, Amit
2013-08-01
Unexpected results were recently reported about the poor surrogacy of Gynecologic Cancer Intergroup (GCIG) defined CA-125 response in recurrent ovarian cancer (ROC) patients. Mathematical modeling may help describe CA-125 decline dynamically and discriminate prognostic kinetic parameters. Data from CALYPSO phase III trial comparing 2 carboplatin-based regimens in ROC patients were analyzed. Based on population kinetic approach, serum [CA-125] concentration-time profiles during first 50 treatment days were fit to a semi-mechanistic model with following parameters: "d[CA-125]/dt=(KPROD∗exp (BETA∗t))∗Effect-KELIM∗[CA-125]" with time, t; tumor growth rate, BETA; CA-125 tumor production rate, KPROD; CA-125 elimination rate, KELIM and K-dependent treatment indirect Effect. The predictive values of kinetic parameters were tested regarding progression-free survival (PFS) against other reported prognostic factors. Individual CA-125 kinetic profiles from 895 patients were modeled. Three kinetic parameters categorized by medians had predictive values using univariate analyses: K; KPROD and KELIM (all PCA-125 response (favoring carboplatin-paclitaxel arm), treatment arm, platinum free-interval, measurable lesions and KELIM (HR=0.53; 95% CI 0.45-0.61; PCA-125 kinetics in ROC patients enables understanding of the time-change components during chemotherapy. The contradictory surrogacy of GCIG-defined CA-125 response was confirmed. The modeled CA-125 elimination rate KELIM, potentially assessable in routine, may have promising predictive value regarding PFS. Further validation of this predictive marker is warranted. Copyright © 2013 Elsevier Inc. All rights reserved.
Directory of Open Access Journals (Sweden)
S. A. Bobrovnik
2016-06-01
Full Text Available The discovered earlier phenomenon of the enhancment of polyreactive immunoglobulines (PRIGs binding to antigens in the presence of protamine and Tween 20 was investigated in more details. The comparative analysis of PRIGs reaction dynamics with immobilized antigen was provided. In addition, the rate constants for the reaction and the affinity constants of PRIGs-antigen binding in the presence or absence of optimal protamine concentration were determined. The rate constant of PRIGs-antigen reaction did not increase in the presence of protamine optimal concentration and was even reduced approximately twice. However, in the presence of protamine the concentration of reactive PRIGs molecules, that were able to interact with antigen, increased approximately 30 times, and this led to strong reaction rate increase. Protamine also influenced the affinity constant of PRIGs-antigen binding, which increased approximately three times. The suggestion was made that such protamine effect was due to its influence on the PRIGs molecules special structure, and, as a result of the conformational change PRIGs became able to bind more effectively to the antigens.
Energy Technology Data Exchange (ETDEWEB)
Morrison, Glenn Charles [Univ. of California, Berkeley, CA (United States)
1999-12-01
In this dissertation, results are presented of laboratory investigations and mathematical modeling efforts designed to better understand the interactions of ozone with surfaces. In the laboratory, carpet and duct materials were exposed to ozone and measured ozone uptake kinetics and the ozone induced emissions of volatile organic compounds. To understand the results of the experiments, mathematical methods were developed to describe dynamic indoor aldehyde concentrations, mass transport of reactive species to smooth surfaces, the equivalent reaction probability of whole carpet due to the surface reactivity of fibers and carpet backing, and ozone aging of surfaces. Carpets, separated carpet fibers, and separated carpet backing all tended to release aldehydes when exposed to ozone. Secondary emissions were mostly n-nonanal and several other smaller aldehydes. The pattern of emissions suggested that vegetable oils may be precursors for these oxidized emissions. Several possible precursors and experiments in which linseed and tung oils were tested for their secondary emission potential were discussed. Dynamic emission rates of 2-nonenal from a residential carpet may indicate that intermediate species in the oxidation of conjugated olefins can significantly delay aldehyde emissions and act as reservoir for these compounds. The ozone induced emission rate of 2-nonenal, a very odorous compound, can result in odorous indoor concentrations for several years. Surface ozone reactivity is a key parameter in determining the flux of ozone to a surface, is parameterized by the reaction probability, which is simply the probability that an ozone molecule will be irreversibly consumed when it strikes a surface. In laboratory studies of two residential and two commercial carpets, the ozone reaction probability for carpet fibers, carpet backing and the equivalent reaction probability for whole carpet were determined. Typically reaction probability values for these materials were 10
International Nuclear Information System (INIS)
Raymond, D.P.; Clough, P.N.
1989-09-01
Heterogeneous reactions may cause enhanced release of radionuclides during the core-concrete interaction (CCl) stage of a PWR severe accident. The VANESA computer code models these CCI releases using chemical equilibrium assumptions; however, the possibility that chemical kinetics could prevent equilibrium from being achieved is considered in this report. Direct experimental evidence is lacking on these reactions. Therefore, some analogues studies are reviewed, including examples of Eyring's surface reaction rate theory; sequential vaporisation-oxidation processes; iron and steelmaking chemistry; radionuclide evaporation from solid UO 2 . This circumstantial evidence appeared to agree with the current assumptions, in VANESA and some UK modelling studies, that mass transfer, rather than chemical kinetics will limit the rate at which equilibrium is attained. (author)
Energy Technology Data Exchange (ETDEWEB)
Misguich, J.H
2004-04-01
As a first step toward a nonlinear renormalized description of turbulence phenomena in magnetized plasmas, the lowest order quasi-linear description is presented here from a unified point of view for collisionless as well as for collisional plasmas in a constant magnetic field. The quasi-linear approximation is applied to a general kinetic equation obtained previously from the Klimontovich exact equation, by means of a generalised Dupree-Weinstock method. The so-obtained quasi-linear description of electromagnetic turbulence in a magnetoplasma is applied to three separate physical cases: -) weak electrostatic turbulence, -) purely magnetic field fluctuations (the classical quasi-linear results are obtained for cosmic ray diffusion in the 'slab model' of magnetostatic turbulence in the solar wind), and -) collisional kinetic equations of magnetized plasmas. This mathematical technique has allowed us to derive basic kinetic equations for turbulent plasmas and collisional plasmas, respectively in the quasi-linear and Landau approximation. In presence of a magnetic field we have shown that the systematic use of rotation matrices describing the helical particle motion allows for a much more compact derivation than usually performed. Moreover, from the formal analogy between turbulent and collisional plasmas, the results derived here in detail for the turbulent plasmas, can be immediately translated to obtain explicit results for the Landau kinetic equation.
International Nuclear Information System (INIS)
Misguich, J.H.
2004-04-01
As a first step toward a nonlinear renormalized description of turbulence phenomena in magnetized plasmas, the lowest order quasi-linear description is presented here from a unified point of view for collisionless as well as for collisional plasmas in a constant magnetic field. The quasi-linear approximation is applied to a general kinetic equation obtained previously from the Klimontovich exact equation, by means of a generalised Dupree-Weinstock method. The so-obtained quasi-linear description of electromagnetic turbulence in a magnetoplasma is applied to three separate physical cases: -) weak electrostatic turbulence, -) purely magnetic field fluctuations (the classical quasi-linear results are obtained for cosmic ray diffusion in the 'slab model' of magnetostatic turbulence in the solar wind), and -) collisional kinetic equations of magnetized plasmas. This mathematical technique has allowed us to derive basic kinetic equations for turbulent plasmas and collisional plasmas, respectively in the quasi-linear and Landau approximation. In presence of a magnetic field we have shown that the systematic use of rotation matrices describing the helical particle motion allows for a much more compact derivation than usually performed. Moreover, from the formal analogy between turbulent and collisional plasmas, the results derived here in detail for the turbulent plasmas, can be immediately translated to obtain explicit results for the Landau kinetic equation
Large-time behavior of discrete kinetic equations with non-symmetric interactions
Arnold, Anton; Carrillo, Jose A.; Tidriri, Moulay D.
2002-01-01
We consieder the initial-boundary value problem for general linear discrete velocity models appearing in kinetic theory. With time independent inflow boundary data we prove the existence of a unique steady state and the exponential convergence in time towards the steady state. The proof is based on the construction of suitable multiplyers used in a weighted L^{2}-norm.
Gálvez, Loli; González, Esther M; Arrese-Igor, Cesar
2005-09-01
Symbiotic N2 fixation in legume nodules declines under a wide range of environmental stresses. A high correlation between N2 fixation decline and sucrose synthase (SS; EC 2.4.1.13) activity down-regulation has been reported, although it has still to be elucidated whether a causal relationship between SS activity down-regulation and N2 fixation decline can be established. In order to study the likely C/N interactions within nodules and the effects on N2 fixation, pea plants (Pisum sativum L. cv. Sugar snap) were subjected to progressive water stress by withholding irrigation. Under these conditions, nodule SS activity declined concomitantly with apparent nitrogenase activity. The levels of UDP-glucose, glucose-1-phosphate, glucose-6-phosphate, and fructose-6-phosphate decreased in water-stressed nodules compared with unstressed nodules. Drought also had a marked effect on nodule concentrations of malate, succinate, and alpha-ketoglutarate. Moreover, a general decline in nodule adenylate content was detected. NADP+-dependent isocitrate dehydrogenase (ICDH; EC 1.1.1.42) was the only enzyme whose activity increased as a result of water deficit, compensating for a possible C/N imbalance and/or supplying NADPH in circumstances that the pentose phosphate pathway was impaired, as suggested by the decline in glucose-6-phosphate dehydrogenase (G6PDH; EC 1.1.1.49) activity. The overall results show the occurrence of strong C/N interactions in nodules subjected to water stress and support a likely limitation of carbon flux that might be involved in the decline of N2 fixation under drought.
Tsuchimochi, Takashi
2015-10-14
Spin-flip approaches capture static correlation with the same computational scaling as the ordinary single reference methods. Here, we extend spin-flip configuration interaction singles (SFCIS) by projecting out intrinsic spin-contamination to make it spin-complete, rather than by explicitly complementing it with spin-coupled configurations. We give a general formalism of spin-projection for SFCIS, applicable to any spin states. The proposed method is viewed as a natural unification of SFCIS and spin-projected CIS to achieve a better qualitative accuracy at a low computational cost. While our wave function ansatz is more compact than previously proposed spin-complete SF approaches, it successfully offers more general static correlation beyond biradicals without sacrificing good quantum numbers. It is also shown that our method is invariant with respect to open-shell orbital rotations, due to the uniqueness of spin-projection. We will report benchmark calculations to demonstrate its qualitative performance on strongly correlated systems, including conical intersections that appear both in ground-excited and excited-excited degeneracies.
Energy Technology Data Exchange (ETDEWEB)
Liao, J. [Brookhaven National Lab. (BNL), Upton, NY (United States); Venugopalan, R. [Brookhaven National Lab. (BNL), Upton, NY (United States); Berges, J. [Brookhaven National Lab. (BNL), Upton, NY (United States); Blaizot, J. -P. [Brookhaven National Lab. (BNL), Upton, NY (United States); Gelis, F. [Brookhaven National Lab. (BNL), Upton, NY (United States)
2014-04-09
The RIKEN BNL Research Center (RBRC) was established in April 1997 at Brookhaven National Laboratory*. It is funded by the ''Rikagaku Kenkyusho'' (RIKEN, The Institute of Physical and Chemical Research) of Japan and the U. S. Department of Energy’s Office of Science. The RBRC is dedicated to the study of strong interactions, including spin physics, lattice QCD, and RHIC physics through the nurturing of a new generation of young physicists. The RBRC has theory, lattice gauge computing and experimental components. It is presently exploring the possibility of an astrophysics component being added to the program. The purpose of this Workshop is to critically review the recent progress on the theory and phenomenology of early time dynamics in relativistic heavy ion collisions from RHIC to LHC energies, to examine the various approaches on thermalization and existing issues, and to formulate new research efforts for the future. Topics slated to be covered include Experimental evidence for equilibration/isotropization, comparison of various approaches, dependence on the initial conditions and couplings, and turbulent cascades and Bose-Einstein condensation.
Measurement of the strong interaction coupling constant αs by jet study in the H1 experiment
International Nuclear Information System (INIS)
Squinabol, F.
1997-01-01
The H1 experiment allows to study hadronic jets produced in deep inelastic lepton (27.5 GeV) scattering off protons (820 GeV). The coupling constant of the strong interaction α s can be extracted from the measurement of the 2-jets rate in the final state. The use of the JADE algorithm is optimal for events with high energy transfer (100-4,000 GeV 2 ), corresponding to the 1994 and 1995 data. The error on α s (M Z 0 2 ) is dominated by the uncertainty from the hadronic energy measurement and the experimental resolution effects on jets. The theoretical error is dominated by the renormalization scale dependence. The final result is (M Z 0 2 ) 0.118 -0.008 +0.008 . This analysis is extended to smaller momentum transfers (25-100 GeV 2 ) using the factorizable K t algorithm, taking the transferred momentum as energy scale of the particle re-clustering. The result α s (M Z 0 2 ) 0.117 -0.008 +0.009 is compatible with the previous one. The precision of the measurement performed in this thesis is 7%. A precision of 4% could be achieved after progresses in the theoretical framework and/or after a significant increase of the luminosity. (author)
Energy Technology Data Exchange (ETDEWEB)
Ruhl, Hartmut [Munich Univ. (Germany). Chair for Computational and Plasma Physics
2016-11-01
Since the installation of SuperMUC phase 2 the 9216 nodes of phase 1 are more easily available for large scale runs allowing for the thin foil and AWAKE simulations. Besides phase 2 could be used in parallel for high throughput of the ion acceleration simulations. Challenging to our project were the full-volume checkpoints required by PIC that strained the I/O-subsystem of SuperMUC to its limits. New approaches considered for the next generation system, like burst buffers could overcome this bottleneck. Additionally, as the FDTD solver in PIC is strongly bandwidth bound, PSC will benefit profoundly from high-bandwidth memory (HBM) that most likely will be available in future HPC machines. This will be of great advantage as in 2018 phase II of AWAKE should begin, with a longer plasma channel further increasing the need for additional computing resources. Last but not least, it is expected that our methods used in plasma physics (many body interaction with radiation) will be more and more adapted for medical diagnostics and treatments. For this research field we expect centimeter sized volumes with necessary resolutions of tens of micro meters resulting in boxes of >10{sup 12} voxels (100-200 TB) on a regular basis. In consequence the demand for computing time and especially for data storage and data handling capacities will also increase significantly.
Lokhande, R. S.; Singare, P. U.; Karthikeyan, P.
2007-11-01
In the present investigation, 82Br radioactive isotope was used as a tracer to study the kinetics and mechanism of exchange reaction between an ion exchange resin and an external bromide ion solution. In an attempt to study the reversible bromide ion isotopic exchange reaction kinetics, it was expected that whether the initial step was the exchange of radioactive bromide ions from the solution into the ion exchange resin (forward reaction) or from the ion exchange resin into the solution (reverse reaction), two ion isotopic exchange reactions should occur simultaneously, which was further confirmed by the experimental specific reaction rates of 0.130 and 0.131 min-1, respectively. The results can be used to standardize process parameters so as to optimize the utilization of ion exchange resins in various industrial applications.
Kolta, A; Lynch, G; Ambros-Ingerson, J
1998-03-30
The modulatory influence of aniracetam, a drug which reversibly modifies the kinetic properties of AMPA-type glutamate receptors, on synaptic responses is reported to be detectably changed by the induction of long-term potentiation (LTP). The present study used hippocampal slices to examine three issues arising from this result. First, possible contributions of inhibitory currents and postsynaptic spiking to the aniracetam/LTP interaction were investigated with infusions of GABA receptor antagonists and topical applications of tetrodotoxin. Second, tests were carried out to determine if the altered response to aniracetam is sufficiently persistent to be a plausible substrate for the extremely stable LTP effect. Third, the nature of the change responsible for the aniracetam/LTP interaction was explored with waveform analyses and a kinetic model of the AMPA receptor. The following results were obtained. LTP reduced the effect of aniracetam on the amplitude but increased its effect on the decay time constant of field EPSPs recorded under conditions in which local spiking and inhibitory responses were blocked. The LTP-induced change in the effect of aniracetam was extremely stable in that it was still evident 75 min after induction of potentiation. Finally, the waveform distortions introduced by LTP and aniracetam could be corrected by uniform stretching of the responses, suggesting that the changes introduced by each of the manipulations are unitary in nature. These distortions and the interactions between them could be reproduced in the AMPA receptor model by representing LTP as an acceleration of channel gating kinetics. Copyright 1998 Elsevier Science B.V.
Directory of Open Access Journals (Sweden)
Faranak Ghaderi
Full Text Available ABSTRACT The Maillard reaction of hydrochlorothiazide (HCTZ and lactose has been previously demonstrated in pharmaceutical formulations. In this study, the activation energy of - hydrohlorothiazide and lactose interaction in the liquid state was ascertained under basic and neutral conditions. Conventional isothermal High Performance Liquid Chromatography (HPLC technique was employed to ascertain the kinetic parameters using Arrhenius method. Results: The activation energy obtained was 82.43 and 100.28 kJ/mol under basic and neutral conditions, respectively. Consequently, it can be inferred that Maillard reaction is significantly affected by pH, which can be used as a control factor whenever the reaction potentially occurs.
International Nuclear Information System (INIS)
Spasennykh, M.Yu.; Apps, J.A.
1995-05-01
A model is developed describing one dimensional radionuclide transport in porous media coupled with locally reversible radionuclide water-mineral exchange reactions and radioactive decay. Problems are considered in which radionuclide transport by diffusion and infiltration processes occur in cases where radionuclide water-solid interaction are kinetically and thermodynamically controlled. The limits of Sr-90 and Cs-137 migration are calculated over a wide range of the problem variables (infiltration velocity, distribution coefficients, and rate constants of water-mineral radionuclide exchange reactions)
International Nuclear Information System (INIS)
Swart, C.A.M. de.
1983-01-01
The author has studied the kinetics of heparin and heparin fractions after intravenous administration in humans and in this thesis the results of this study are reported. Basic knowledge about the physico-chemical properties of heparin and its interactions with proteins resulting in anticoagulant and lipolytic effects are discussed in a review (chapter II), which also comprises some clinical aspects of heparin therapy. In chapter III the kinetics of the anticoagulant effect are described after intravenous administration of five commercial heparin preparations. A mathematical model is presented that fits best to these kinetics. The kinetics of the anticoagulant and lipolytic effects after intravenous injection of various 35 S-radiolabelled heparin fractions and their relationship with the disappearance of the radiolabel are described in chapter IV. Chapter V gives a description of the kinetics of two radiolabels after injection of in vitro formed complexes consisting of purified, 125 I-radiolabelled antithrombin III and various 35 S-radiolabelled heparin fractions. (Auth.)
Costa, Luiz Antônio S.; Hambley, Trevor W.; Rocha, Willian R.; Almeida, Wagner B. De; Dos Santos, Hélio F.
The interaction of cisplatin with guanine DNA bases has been investigated using ab initio Hartree-Fock (HF) and density functional levels of theory in gas phase and aqueous solution. The overall process was divided into three steps: the reaction of the monoaqua [Pt(NH3)2Cl(H2O)]+ species with guanine (G) (reaction 1), the hydrolysis process yielding the adduct [Pt(NH3)2(G) (H2O)]2+ (reaction 2) and the reaction with a second guanine leading to the product [Pt(NH3)2(G)2]2+ (reaction 3). The functionals B3LYP, BHandH, and mPW1PW91 were used in the present study, to develop an understanding of the role of the distinct models. The geometries presented for the intermediate structures were obtained by IRC calculations from the transition state structure for each reaction. The structural analysis for the intermediates and transition states showed that hydrogen bonds with the guanine O6 atom play an important role in stabilizing these species. The geometries were not very sensitive to the level of theory applied with the HF level, giving a satisfactory overall performance. However, the energy barriers and the rate constants were found to be strongly dependent on the level of calculation and basis set, with the DFT calculations giving more accurate results. For reaction 1 the rate constant calculated in aqueous solution at PCM-BHandH/6-311G* (k1 = 7.55 × 10-1 M-1 s-1) was in good agreement with the experiment (5.4 × 10-1 M-1 s-1). The BHandH/6-31G* calculated gas phase rate constants for reactions 2 and 3 were: k2 = 0.9 × 10-6 M-1 s-1 and k3 = 2.99 × 10-4 M-1 s-1 in fairly good accordance with the experimental findings for reaction 2 (1.0 × 10-6 M-1 s-1) and reaction 3 (3.0 × 10-4 M-1 s-1).
Directory of Open Access Journals (Sweden)
Rachid Rezgui
Full Text Available As DNA repair enzymes are essential for preserving genome integrity, understanding their substrate interaction dynamics and the regulation of their catalytic mechanisms is crucial. Using single-molecule imaging, we investigated the association and dissociation kinetics of the bipolar endonuclease NucS from Pyrococcus abyssi (Pab on 5' and 3'-flap structures under various experimental conditions. We show that association of the PabNucS with ssDNA flaps is largely controlled by diffusion in the NucS-DNA energy landscape and does not require a free 5' or 3' extremity. On the other hand, NucS dissociation is independent of the flap length and thus independent of sliding on the single-stranded portion of the flapped DNA substrates. Our kinetic measurements have revealed previously unnoticed asymmetry in dissociation kinetics from these substrates that is markedly modulated by the replication clamp PCNA. We propose that the replication clamp PCNA enhances the cleavage specificity of NucS proteins by accelerating NucS loading at the ssDNA/dsDNA junctions and by minimizing the nuclease interaction time with its DNA substrate. Our data are also consistent with marked reorganization of ssDNA and nuclease domains occurring during NucS catalysis, and indicate that NucS binds its substrate directly at the ssDNA-dsDNA junction and then threads the ssDNA extremity into the catalytic site. The powerful techniques used here for probing the dynamics of DNA-enzyme binding at the single-molecule have provided new insight regarding substrate specificity of NucS nucleases.
Shin, H C; Quinn, D M
1992-01-28
The interaction of lipoprotein lipase with p-nitrophenyl N-alkylcarbamates [PNPOC(=O)-NHCnH2n+1; n = 4, 8, and 12] proceeds by the three-stage mechanism shown below. After reversible [formula: see text] formation of the enzyme-carbamate complex (EC), rapid carbamylation (kc) precedes slow decarbamylation. Therefore, in short-term assays (less than or equal to 30 min) of lipoprotein lipase catalyzed hydrolysis of p-nitrophenyl butyrate, activity is rapidly lost. The inhibition by p-nitrophenyl N-butylcarbamate follows saturation kinetics, which allows determination of Kc = 5.4 +/- 0.9 microM and kc = (4.9 +/- 0.7) x 10(-2)s-1. Saturation kinetics are not observed for the longer inhibitors p-nitrophenyl N-octylcarbamate and p-nitrophenyl N-dodecylcarbamate. Rather, plots of the pseudo-first-order rate constant for activity loss versus inhibitor concentration are concave upward, consistent with inhibitor binding to two sites on the enzyme. The inhibition phase is sufficiently rapid that p-nitrophenyl N-octylcarbamate can be used to titrate enzyme active sites. On the other hand, long-term assays (greater than 5 h) show sequential inhibition and activity return phases, and from the activity return phase kd is calculated. The long-term activity time course is accurately simulated by Runge-Kutta integration of the differential equations for the three-stage mechanism. These approaches have been used to characterize the kinetics of interaction of the enzyme with the carbamate inhibitors.(ABSTRACT TRUNCATED AT 250 WORDS)
Wille, Timo; Kaltenbach, Lisa; Thiermann, Horst; Worek, Franz
2013-12-05
Carbamates are widely used for pest control and act primarily by inhibition of insect and mammalian acetylcholinesterase (AChE). Accidental or intentional uptake of carbamates may result in typical signs and symptoms of cholinergic overstimulation which cannot be discriminated from those of organophosphorus pesticide poisoning. There is an ongoing debate whether standard treatment with atropine and oximes should be recommended for human carbamate poisoning as well, since in vitro and in vivo animal data indicate a deleterious effect of oximes when used in combination with the N-methyl carbamate carbaryl. Therefore, we performed an in vitro kinetic study to investigate the effect of clinically used oximes on carbamoylation and decarbamoylation of human AChE. It became evident that pralidoxime and obidoxime in therapeutic concentrations aggravate the inhibition of AChE by carbaryl and propoxur, with obidoxime being substantially more potent compared to 2-PAM. However, obidoxime had no impact on the decarbamoylation kinetics. Hence, the administration of 2-PAM and especially of obidoxime to severely propoxur and carbaryl poisoned humans cannot be recommended. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.
A thermodynamic and kinetic model for paste–aggregate interactions and the alkali–silica reaction
International Nuclear Information System (INIS)
Guthrie, George D.; Carey, J. William
2015-01-01
A new conceptual model is developed for ASR formation based on geochemical principles tied to aqueous speciation, silica solubility, kinetically controlled mineral dissolution, and diffusion. ASR development is driven largely by pH and silica gradients that establish geochemical microenvironments between paste and aggregate, with gradients the strongest within the aggregate adjacent to the paste boundary (i.e., where ASR initially forms). Super-saturation of magadiite and okenite (crystalline ASR surrogates) occurs in the zone defined by gradients in pH, dissolved silica, Na + , and Ca 2 + . This model provides a thermodynamic rather than kinetic explanation of why quartz generally behaves differently from amorphous silica: quartz solubility does not produce sufficiently high concentrations of H 4 SiO 4 to super-saturate magadiite, whereas amorphous silica does. The model also explains why pozzolans do not generate ASR: their fine-grained character precludes formation of chemical gradients. Finally, these gradients have interesting implications beyond the development of ASR, creating unique biogeochemical environments
Interactions among contaminant exposure route, kinetics and toxicity in marine deposit-feeders
DEFF Research Database (Denmark)
Selck, Henriette
of a contaminant is bioavailable. The relationship among different combinations of exposure route (water vs. sediment), kinetics (i.e. uptake, internal fate, elimination) and toxicity were investigated in the polychaete Capitella species I and the brittle star Amphiura filiformis. Fluoranthene was used......Many of the chemicals having the greatest likelihood of causing damage in ecological systems, such as polycyclic aromatic hydrocarbons (PAHs) and metals are of persistent and/or hydrophobic character. Deposit-feeders may be important in facilitating the removal of organic contaminants from bulk...... and more ecologically relevant methods for use in risk assessment, relationships among adverse effects, time-dependent availability, internal transport and potential for trophic transfer need to be addressed....
Alvarado, F; Robinson, J W
1979-10-01
1. The influx of amino acids into guinea-pig intestinal rings in vitro is inhibited by monosaccharides, and that of monosaccharides by amino acids. Two hypotheses have been proposed to account for these heterologous interactions. According to the first, the cis hypothesis, there is an allosteric interaction between substrates binding to separate but related sites at the outer face of the brush-border membrane matrix. In contrast, the trans hypothesis envisages the interaction to result from a partial dissipation of the electrochemical sodium gradient due to the cotransport of each substrate with sodium ions. 2. In an attempt to distinguish between the merits of the two hypotheses, we examined the kinetics of the inhibition of phenylalanine influx by two sugars of widely different affinities, galactose and beta-methylglucoside. Since beta-methylglucoside carries more sodium into the cell than galactose, the trans hypothesis would predict it to be the stronger inhibitor, but in fact the opposite result is found. 3. Equations were developed to describe the inhibitions in accordance with the cis hypothesis. The satisfactory agreement between experimental observations and theoretical predictions provides support for the applicability of the model. Further implications of the polyfunctional carrier model are discussed.
Henrickson, Sarah E; Perro, Mario; Loughhead, Scott M; Senman, Balimkiz; Stutte, Susanne; Quigley, Michael; Alexe, Gabriela; Iannacone, Matteo; Flynn, Michael P; Omid, Shaida; Jesneck, Jonathan L; Imam, Sabrina; Mempel, Thorsten R; Mazo, Irina B; Haining, W Nicholas; von Andrian, Ulrich H
2013-09-19
T cells are activated by antigen (Ag)-bearing dendritic cells (DCs) in lymph nodes in three phases. The duration of the initial phase of transient, serial DC-T cell interactions is inversely correlated with Ag dose. The second phase, characterized by stable DC-T cell contacts, is believed to be necessary for full-fledged T cell activation. Here we have shown that this is not the case. CD8⁺ T cells interacting with DCs presenting low-dose, short-lived Ag did not transition to phase 2, whereas higher Ag dose yielded phase 2 transition. Both antigenic constellations promoted T cell proliferation and effector differentiation but yielded different transcriptome signatures at 12 hr and 24 hr. T cells that experienced phase 2 developed long-lived memory, whereas conditions without stable contacts yielded immunological amnesia. Thus, T cells make fate decisions within hours after Ag exposure, resulting in long-term memory or abortive effector responses, correlating with T cell-DCs interaction kinetics. Copyright © 2013 Elsevier Inc. All rights reserved.
Directory of Open Access Journals (Sweden)
Elbager M.A. Edreis
2017-04-01
Full Text Available In this study the effects of iron chloride (FeCl3 on the CO2 gasification kinetics of lower sulphur petroleum coke (PC and sugar cane bagasse (SCB via thermogravimetric analyser (TGA were investigated. The FeCl3 loading effects on the thermal behaviour and reactivity of CO2 gasification of PC were studied. The possible synergistic interaction between the PC and SCB was also examined. Then the homogeneous model or first order chemical reaction (O1 and shrinking core models (SCM or phase boundary controlled reactions (R2 and R3 were employed through Coats–Redfern method in order to detect the optimum mechanisms for the catalytic CO2 gasification, describe the best reaction behaviour and determine the kinetic parameters. The results showed that the thermal behaviour of PC is significantly affected by the FeCl3 loading. Among various catalyst loadings, the addition of 7 wt% FeCl3 to PC leads to improve the PC reactivity up to 39% and decrease the activation energy up to 22%. On the other hand, for char gasification stage of SCB and blend, the addition 5 wt% FeCl3 improved their reactivities to 18.7% and 29.8% and decreased the activation energies to 10% and 17%, respectively. The synergistic interaction between the fuel blend was observed in both reaction stages of the blend and became more significant in the pyrolysis stage. For all samples model R2 shows the lowest values of activation energy (E and the highest reaction rates constant (k. Finally, model R2 was the most suitable to describe the reactions of non-catalytic and catalytic CO2 gasification.
Structural and Kinetic Analyses of Macrophage Migration Inhibitory Factor Active Site Interactions
Energy Technology Data Exchange (ETDEWEB)
Crichlow, G.; Lubetsky, J; Leng, L; Bucala, R; Lolis, E
2009-01-01
Macrophage migration inhibitory factor (MIF) is a secreted protein expressed in numerous cell types that counters the antiinflammatory effects of glucocorticoids and has been implicated in sepsis, cancer, and certain autoimmune diseases. Interestingly, the structure of MIF contains a catalytic site resembling the tautomerase/isomerase sites of microbial enzymes. While bona fide physiological substrates remain unknown, model substrates have been identified. Selected compounds that bind in the tautomerase active site also inhibit biological functions of MIF. It had previously been shown that the acetaminophen metabolite, N-acetyl-p-benzoquinone imine (NAPQI), covalently binds to the active site of MIF. In this study, kinetic data indicate that NAPQI inhibits MIF both covalently and noncovalently. The structure of MIF cocrystallized with NAPQI reveals that the NAPQI has undergone a chemical alteration forming an acetaminophen dimer (bi-APAP) and binds noncovalently to MIF at the mouth of the active site. We also find that the commonly used protease inhibitor, phenylmethylsulfonyl fluoride (PMSF), forms a covalent complex with MIF and inhibits the tautomerase activity. Crystallographic analysis reveals the formation of a stable, novel covalent bond for PMSF between the catalytic nitrogen of the N-terminal proline and the sulfur of PMSF with complete, well-defined electron density in all three active sites of the MIF homotrimer. Conclusions are drawn from the structures of these two MIF-inhibitor complexes regarding the design of novel compounds that may provide more potent reversible and irreversible inhibition of MIF.
Kinetic analysis of interaction between N atoms and O-covered Ru(0001)
Kang, Kai; Kleyn, A. W.; Gleeson, M. A.
2015-10-01
Eley-Rideal (ER) reactions involving neutral atoms heavier than hydrogen reacting with adsorbed atoms of similar mass were first observed in recent molecular beam experiments by Zaharia et al. [Phys. Rev. Lett. 113, 053201 (2014)]. Through analysis of two types of measurements, they obtained different estimations for the N-O ER reaction cross section, one of which is unexpectedly high. This was qualitatively accounted for by invoking a secondary effect whereby the presence of N adatoms on the surface acted to "shield" O adatoms from prompt recombinative desorption. We apply a rate equation model that includes two ER processes involving different adsorbed species (N-Oad and N-Nad) and an N-adsorption process to the full-beam exposure subset of the experimental data in order to study the reaction kinetics. Values for the individual reaction cross sections are derived. The measured N2 response can be well described by the model, but it is insufficient to completely describe the NO response. Modeling of different exposures is used to evaluate the qualitative picture presented by Zaharia et al.
Directory of Open Access Journals (Sweden)
Saha Sushanta
2007-10-01
Full Text Available Abstract Background The anticancer properties of cisplatin and palladium(II complexes stem from the ability of the cis-MCl2 fragment to bind to DNA bases. However, cisplatin also interacts with non-cancer cells, mainly through bonding molecules containing -SH groups, resulting in nephrotoxicity. This has aroused interest in the design of palladium(II complexes of improved activity and lower toxicity. The reaction of DNA bases with palladium(II complexes with chelating N,N/donors of the cis-MCl2 configuration constitutes a model system that may help explore the mechanism of cisplatin's anticancer activity. Heterocyclic compounds are found widely in nature and are essential to many biochemical processes. Amongst these naturally occurring compounds, the most thoroughly studied is that of pyrimidine. This was one of the factors that encouraged this study into the kinetics and mechanism of the interaction of 2-aminopyrimidine (2-NH2-Pym with dichloro-{1-alkyl-2-(α-naphthylazoimidazole}palladium(II [Pd(α-NaiRCl2, 1] and dichloro-{1-alkyl-2-(β-naphthylazoimidazole}palladium(II [Pd(β-NaiRCl2, 2] complexes where the alkyl R = Me (a, Et (b, or Bz (c. Results 2-NH2-Pym reacts with 1a, 1b, and 1c to yield [{1-alkyl-2-(α-naphthylazoimidazole}bis(2-aminopyrimidine]palladium(II (3a, 3b, 3c dichloride and with 2a, 2b, and 2c to yield [{1-alkyl-2-(β-naphthylazoimidazole}bis(2-aminopyrimidine]palladium(II (4a, 4b, 4c dichloride in an acetonitrile (MeCN medium. The products were characterized using spectroscopic techniques (FT-IR, UV-Vis, NMR. The ligand substitution reactions follow second order kinetics – first order dependence on the concentration of the Pd(II complex and 2-NH2-Pym. Addition of LiCl to the reaction does not influence its rate. The thermodynamic parameters (standard enthalpy of activation, Δ‡H° and standard entropy of activation, Δ‡S° were determined from variable temperature kinetic studies. The magnitude of the second order
Yu, Bryan Lei; Han, Jun; Hammond, Matthew; Wang, Xuemei; Zhang, Qingchun; Clausen, Andrew; Forster, Ronald; Eu, Mingda
Ethylene oxide (ETO) is commonly used to sterilize plastic containers, but the effects of residual amounts left after sterilization on protein therapeutics are still not well understood. Here we focus primarily on the factors that influence concentrations of ETO migrating from ETO-treated plastic containers into aqueous solution. A study was designed to investigate the kinetics of this process at various temperatures, and the kinetic data could be fit with a model based on a combination of Fickean diffusion and first-order chemical reaction (to account for observed hydrolysis of ETO). The diffusion and reaction rate constants thus obtained obey Arrhenius-like temperature dependence. These results indicate that for analytical methods involving extraction into water, measurements of residual ETO in a container must account for the effects of ETO hydrolysis. Further, the effects of salt concentration and pH of the fluid in the container on accumulated ETO levels were explored. Finally, interactions of ETO with anti-streptavidin (AntiSA) Immunoglobulin G1 (IgG1) and IgG2 antibodies were studied, with ETO adducts found on all methionine residues when incubated in solutions spiked with ETO at concentrations that could be reached (based on the kinetic studies) in ETO-treated plastic vials. Overall, the likelihood of observable ETO-protein modifications upon storage in ETO-sterilized containers will depend on a complex interplay of protein properties, formulation details, storage conditions, and amount of residual ETO initially in the container. Ethylene oxide (ETO) is commonly used to sterilize plastic containers, but the effects of residual amounts left after sterilization on protein therapeutics are still not well understood. Here we describe experiments exploring the factors that influence concentrations of ETO migrating from ETO-treated plastic containers into aqueous solution over time. Additionally, interactions of ETO with model antibodies were studied, with ETO
DEFF Research Database (Denmark)
Van Vlack, C.; Kristensen, Philip Trøst; Hughes, S.
2012-01-01
the dot to the detector, we demonstrate that the strong-coupling regime should be observable in the far-field spontaneous emission spectrum, even at room temperature. The vacuum-induced emission spectra show that the usual vacuum Rabi doublet becomes a rich spectral triplet or quartet with two of the four...
Energy Technology Data Exchange (ETDEWEB)
Casalderrey-Solana, Jorge [Departament d' Estructura i Constituents de la Matèria and Institut de Ciències del Cosmos (ICCUB), Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona (Spain); Rudolf Peierls Centre for Theoretical Physics, University of Oxford, 1 Keble Road, Oxford OX1 3NP (United Kingdom); Gulhan, Doga Can [Laboratory for Nuclear Science and Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Milhano, José Guilherme [CENTRA, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, P-1049-001 Lisboa (Portugal); Physics Department, Theory Unit, CERN, CH-1211 Genève 23 (Switzerland); Pablos, Daniel [Departament d' Estructura i Constituents de la Matèria and Institut de Ciències del Cosmos (ICCUB), Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona (Spain); Rajagopal, Krishna [Laboratory for Nuclear Science and Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)
2016-12-15
Within a hybrid strong/weak coupling model for jets in strongly coupled plasma, we explore jet modifications in ultra-relativistic heavy ion collisions. Our approach merges the perturbative dynamics of hard jet evolution with the strongly coupled dynamics which dominates the soft exchanges between the fast partons in the jet shower and the strongly coupled plasma itself. We implement this approach in a Monte Carlo, which supplements the DGLAP shower with the energy loss dynamics as dictated by holographic computations, up to a single free parameter that we fit to data. We then augment the model by incorporating the transverse momentum picked up by each parton in the shower as it propagates through the medium, at the expense of adding a second free parameter. We use this model to discuss the influence of the transverse broadening of the partons in a jet on intra-jet observables. In addition, we explore the sensitivity of such observables to the back-reaction of the plasma to the passage of the jet.
Kinetic investigation of myeloperoxidase upon interaction with copper, cadmium, and lead ions
International Nuclear Information System (INIS)
Shabani, M.; Ani, M.; Movahedian, A.; Samsam Shariat, Z. A.
2011-01-01
Myeloperoxidase, which is abundantly expressed in neutrophils, catalyzes the formation of a number of reactive oxidant species. However, evidence has emerged that Myeloperoxidase-derived oxidants contribute to tissue damage and initiation and propagation of inflammatory diseases, particularly, cardiovascular diseases. Therefore, studying the regulatory mechanisms of the enzyme activity is of great importance. For clarifying some possible mechanism of the enzyme activity, kinetic investigations of Myeloperoxidase in the presence of Copper, Cadmium, and Lead ions were carried out in vitro. Methods: Myeloperoxidase was partially purified from human white blood cells using ion-exchange and gel-filtration chromatography techniques. Its activity was measured spectrophotometrically by using tetramethyl benzidine as substrate. Results: Purified enzyme had a specific activity of 21.7 U/mg protein with a purity index of about 0.71. Copper inhibited Myeloperoxidase activity progressively up to a concentration of 60 m M at which about 80% of inhibition achieved. The inhibition was non-competitive with respect to tetramethyl benzidine. An inhibitory constant (Ki) of about 19 m M was calculated from the slope of repot. Cadmium and Lead did not show any significant inhibitory effect on the enzyme activity. Conclusion: The results of the present study may indicate that there are some places on the enzyme and enzyme-substrate complex for Copper ions. Binding of Copper ions to these places result in conformational changes of the enzyme and thus, enzyme inhibition. This inhibitory effect of Copper on the enzyme activity might be considered as a regulatory mechanism on Myeloperoxidase activity.
Keren, Yonatan; Borisover, Mikhail; Schaumann, Gabriele E.; Diehl, Dörte; Tamimi, Nisreen; Bukhanovsky, Nadezhda
2017-04-01
Sorption interactions with soils are well known to control the environmental fate of multiple organic compounds including pesticides. Pesticide-soil interactions may be affected by organic amendments or organic matter (OM)-containing wastewater brought to the field. Specifically, land spreading of olive mill wastewater (OMW), occurring intentionally or not, may also influence pesticide-soil interactions. The effects of the OMW disposed in the field on soil properties, including their ability to interact with pesticides, become of great interest due to the increasing demand for olive oil and a constant growth of world oil production. This paper summarizes some recent findings related to the effect of prior OMW land application on the ability of soils to interact with the organic compounds including pesticides, diuron and simazine. The major findings are as following: (1) bringing OMW to the field increases the potential of soils to sorb non-ionized pesticides; (2) this sorption increase may not be related solely to the increase in soil organic carbon content but it can reflect also the changes in the soil sorption mechanisms; (3) increased pesticide interactions with OMW-affected soils may become irreversible, due, assumedly, to the swelling of some components of the OMW-treated soil; (4) enhanced pesticide-soil interactions mitigate with the time passed after the OMW application, however, in the case of diuron, the remaining effect could be envisioned at least 600 days after the normal OMW application; (5) the enhancement effect of OMW application on soil sorption may increase with soil depth, in the 0-10 cm interval; (6) at higher pesticide (diuron) concentrations, larger extents of sorption enhancement, following the prior OMW-soil interactions, may be expected; (7) disposal of OMW in the field may be seasonal-dependent, and, in the case studied, it led to more distinct impacts on sorption when carried out in spring and winter, as compared with summer. It appears
Energy Technology Data Exchange (ETDEWEB)
Brun, Ch
1998-04-02
In the context of thermal-hydraulics of nuclear reactors, strong interaction between wakes is encountered in the bottom of reactor vessels where control and measurement rods of variable size and disposition interact with the overall wakes generated in these flow zones. This study deals with the strong interaction between two wakes developed downstream of two parallel cylinders with a small spacing. The analysis focusses on the effect of the Reynolds regime which controls the equilibrium between the inertia and viscosity forces of the fluid and influences the large scale behaviour of the flow with the development of hydrodynamic instabilities and turbulence. The document is organized as follows: the characteristic phenomena of wakes formation downstream of cylindrical obstacles are recalled in the first chapter (single cylinder, interaction between two tubes, case of a bundle of tubes perpendicular to the flow). The experimental setup (hydraulic loop, velocity and pressure measurement instrumentation) and the statistical procedures applied to the signals measured are detailed in chapters 2 and 3. Chapter 4 is devoted to the experimental study of the strong interaction between two tubes. Laser Doppler velocity measurements in the wakes close to cylinders and pressure measurements performed on tube walls are reported in this chapter. In chapter 5, a 2-D numerical simulation of two typical cases of interaction (Re = 1000 and Re = 5000) is performed. In the last chapter, a more complex application of strong interactions inside and downstream of a bunch of staggered tubes is analyzed experimentally for equivalent Reynolds regimes. (J.S.)
Bogodaev, N. V.; Zozulya, A. A.; Ivleva, Lyudmila I.; Korshunov, A. S.; Mamaev, A. V.; Polozkov, N. M.
1992-05-01
Most photorefractive crystals suitable for four-wave systems of phase self-conjugation and mutual conjugation have a fairly high level of light-induced scattering (fanning). This may imply that the nonlinearity of a crystal is too strong for optimal operation and a reduction in this nonlinearity would improve the characteristics. This statement is illustrated theoretically and experimentally using the geometry of a loop parametric oscillator as an example.
International Nuclear Information System (INIS)
Flambaum, V.V.; Shuryak, E.V.
2002-01-01
Recent data on the cosmological variation of the electromagnetic fine structure constant from distant quasar (QSO) absorption spectra have inspired a more general discussion of the possible variation of other constants. We discuss the variation of strong scale and quark masses. We derive limits on their relative change from (i) primordial big bang nucleosynthesis, (ii) the Oklo natural nuclear reactor, (iii) quasar absorption spectra, and (iv) laboratory measurements of hyperfine intervals
Energy Technology Data Exchange (ETDEWEB)
Cao, Jinjia; Gong, Xueyu; Xiang, Dong; Huang, Qianhong [School of Nuclear Science and Technology, University of South China, Hengyang 421001 (China); Wang, Aike [Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041 (China); Yu, Jun [School of Mathematics and Physics, University of South China, Hengyang 421001 (China)
2016-01-15
The enhanced transport of passing energetic ions (PEIs) in presence of the resonant interactions with a rotating magnetic island is investigated within the drift kinetic framework. When the island rotation plays a role in the resonant interaction, we find that the velocities of PEIs satisfy a constraint relation of resonant flux surface in phase space. The resonant flux surfaces overlap with the magnetic flux surfaces in real space. A new transport channel responsible for the PEIs moving across the magnetic flux surfaces, i.e., continuously overlapping, is found. Two kinds of radial motions can be induced by the surface overlapping: one arises from the coupling between the resonance and the collision with the background plasma and the other from not completely overlapping of the two surfaces. The two radial motions and the symmetry-breaking induced radial motion constitute the total radial motion. When the pitch-angle scattering rate is very weak, the surface-shear induced transport is dominant. Only a small increase in the collision rate can significantly influence the total transport.
AUTHOR|(INSPIRE)INSPIRE-00508100
The strong interaction is one of the four fundamental forces of nature. It binds together quarks inside protons and neutrons (which are example of baryons - particles composed of three quarks) and assures the stability of the atomic nucleus. Parameters describing the strong potential are also crucial for the neutron stars models used in astrophysics. What is more, a precise study of strongly interacting particles may help to better understand the process of baryon annihilation. The current knowledge of the strong interactions between baryons other than nucle- ons is limited - there exist only a few measurements of the cross sections for pairs of (anti)baryons. The reason is that in many cases it is not possible to perform scattering experiments with beams of particles and antiparticles, as the exotic matter (such as Λ, Ξ or Σ baryons) is very shot-living. This issue can be solved thanks to the recent particle colliders like the Large Hadron Collider and experiments dedicated to study the heavy-ion collisio...
Directory of Open Access Journals (Sweden)
Kawasaki Masahiro
2012-02-01
Full Text Available The plateau of 7Li abundance as a function of the iron abundance by spectroscopic observations of metal-poor halo stars (MPHSs indicates its primordial origin. The observed abundance levels are about a factor of three smaller than the primordial 7Li abundance predicted in the standard Big Bang Nucleosynthesis (BBN model. This discrepancy might originate from exotic particle and nuclear processes operating in BBN epoch. Some particle models include heavy (m >> 1 GeV long-lived colored particles which would be confined inside exotic heavy hadrons, i.e., strongly interacting massive particles (SIMPs. We have found reactions which destroy 7Be and 7Li during BBN in the scenario of BBN catalyzed by a long-lived sub-strongly interacting massive particle (sub-SIMP, X. The reactions are non radiative X captures of 7 Be and 7Li which can be operative if the X particle interacts with nuclei strongly enough to drive 7 Be destruction but not strongly enough to form a bound state with 4 He of relative angular momentum L = 1. We suggest that 7Li problem can be solved as a result of a new process beyond the standard model through which the observable signature was left on the primordial Li abundance.
Kinetics of drug-ribosome interactions defines the cidality of macrolide antibiotics.
Svetlov, Maxim S; Vázquez-Laslop, Nora; Mankin, Alexander S
2017-12-26
Antibiotics can cause dormancy (bacteriostasis) or induce death (cidality) of the targeted bacteria. The bactericidal capacity is one of the most important properties of antibacterial agents. However, the understanding of the fundamental differences in the mode of action of bacteriostatic or bactericidal antibiotics, especially those belonging to the same chemical class, is very rudimentary. Here, by examining the activity and binding properties of chemically distinct macrolide inhibitors of translation, we have identified a key difference in their interaction with the ribosome, which correlates with their ability to cause cell death. While bacteriostatic and bactericidal macrolides bind in the nascent peptide exit tunnel of the large ribosomal subunit with comparable affinities, the bactericidal antibiotics dissociate from the ribosome with significantly slower rates. The sluggish dissociation of bactericidal macrolides correlates with the presence in their structure of an extended alkyl-aryl side chain, which establishes idiosyncratic interactions with the ribosomal RNA. Mutations or chemical alterations of the rRNA nucleotides in the drug binding site can protect cells from macrolide-induced killing, even with inhibitor concentrations that significantly exceed those required for cell growth arrest. We propose that the increased translation downtime due to slow dissociation of the antibiotic may damage cells beyond the point where growth can be reinitiated upon the removal of the drug due to depletion of critical components of the gene-expression pathway.
Directory of Open Access Journals (Sweden)
Finkelstein Alexei V
2007-07-01
Full Text Available Abstract Background The prediction of ligand binding or protein structure requires very accurate force field potentials – even small errors in force field potentials can make a 'wrong' structure (from the billions possible more stable than the single, 'correct' one. However, despite huge efforts to optimize them, currently-used all-atom force fields are still not able, in a vast majority of cases, even to keep a protein molecule in its native conformation in the course of molecular dynamics simulations or to bring an approximate, homology-based model of protein structure closer to its native conformation. Results A strict analysis shows that a specific coupling of multi-atom Van der Waals interactions with covalent bonding can, in extreme cases, increase (or decrease the interaction energy by about 20–40% at certain angles between the direction of interaction and the covalent bond. It is also shown that on average multi-body effects decrease the total Van der Waals energy in proportion to the square root of the electronic component of dielectric permittivity corresponding to dipole-dipole interactions at small distances, where Van der Waals interactions take place. Conclusion The study shows that currently-ignored multi-atom Van der Waals interactions can, in certain instances, lead to significant energy effects, comparable to those caused by the replacement of atoms (for instance, C by N in conventional pairwise Van der Waals interactions.
Physics of Strongly Coupled Plasma
Energy Technology Data Exchange (ETDEWEB)
Kraeft, Wolf-Dietrich [Universitat Rostock (Germany)
2007-07-15
Strongly coupled plasmas (or non-ideal plasmas) are multi-component charged many-particle systems, in which the mean value of the potential energy of the system is of the same order as or even higher than the mean value of the kinetic energy. The constituents are electrons, ions, atoms and molecules. Dusty (or complex) plasmas contain still mesoscopic (multiply charged) particles. In such systems, the effects of strong coupling (non-ideality) lead to considerable deviations of physical properties from the corresponding properties of ideal plasmas, i.e., of plasmas in which the mean kinetic energy is essentially larger than the mean potential energy. For instance, bound state energies become density dependent and vanish at higher densities (Mott effect) due to the interaction of the pair with the surrounding particles. Non-ideal plasmas are of interest both for general scientific reasons (including, for example, astrophysical questions), and for technical applications such as inertially confined fusion. In spite of great efforts both experimentally and theoretically, satisfactory information on the physical properties of strongly coupled plasmas is not at hand for any temperature and density. For example, the theoretical description of non-ideal plasmas is possible only at low densities/high temperatures and at extremely high densities (high degeneracy). For intermediate degeneracy, however, numerical experiments have to fill the gap. Experiments are difficult in the region of 'warm dense matter'. The monograph tries to present the state of the art concerning both theoretical and experimental attempts. It mainly includes results of the work performed in famous Russian laboratories in recent decades. After outlining basic concepts (chapter 1), the generation of plasmas is considered (chapter 2, chapter 3). Questions of partial (chapter 4) and full ionization (chapter 5) are discussed including Mott transition and Wigner crystallization. Electrical and
Sowole, Modupeola A; Konermann, Lars
2014-07-01
Hydrogen/deuterium exchange (HDX) methods are widely used for monitoring protein-ligand interactions. This approach relies on the fact that ligand binding can modulate the extent of protein structural fluctuations that transiently disrupt hydrogen bonds and expose backbone amides to the solvent. It is commonly observed that ligand binding causes a reduction of HDX rates. This reduction can be restricted to elements adjacent to the binding site, but other regions can be affected as well. Qualitatively, ligand-induced HDX protection can be rationalized on the basis of two-state models that equate structural dynamics with global unfolding/refolding. Unfortunately, such models tend to be unrealistic because the dynamics of native proteins are dominated by subglobal transitions and local fluctuations. Ligand binding lowers the ground-state free energy. It is not obvious why this should necessarily be accompanied by a depletion of excited-state occupancies, which would be required for a reduction of HDX rates. Here, we propose a framework that implies that ligand binding can either slow or accelerate amide deuteration throughout the protein. These scenarios are referred to as "type 1" and "type 2", respectively. Evidence for type 1 binding is abundant in the literature, whereas the viability of type 2 interactions is less clear. Using HDX mass spectrometry (MS), we demonstrate that the oxygenation of hemoglobin (Hb) provides a dramatic example of a type 2 scenario. The observed behavior is consistent with cooperative T → R switching, where part of the intrinsic O2 binding energy is reinvested for destabilization of the ground state. This destabilization increases the Boltzmann occupancy of unfolded conformers, thereby enhancing HDX rates. Surprisingly, O2 binding to myoglobin (Mb) also induces elevated HDX rates. These Mb data reveal that type 2 behavior is not limited to cooperative multisubunit systems. Although enhanced protection from deuteration is widely
International Nuclear Information System (INIS)
Son, Minho; Urbano, Alfredo
2016-01-01
We interpret the recently observed excess in the diphoton invariant mass as a new spin-0 resonant particle. On theoretical grounds, an interesting question is whether this new scalar resonance belongs to a strongly coupled sector or a well-defined weakly coupled theory. A possible UV-completion that has been widely considered in literature is based on the existence of new vector-like fermions whose loop contributions — Yukawa-coupled to the new resonance — explain the observed signal rate. The large total width preliminarily suggested by data seems to favor a large Yukawa coupling, at the border of a healthy perturbative definition. This potential problem can be fixed by introducing multiple vector-like fermions or large electric charges, bringing back the theory to a weakly coupled regime. However, this solution risks to be only a low-energy mirage: large multiplicity or electric charge can dangerously reintroduce the strong regime by modifying the renormalization group running of the dimensionless couplings. This issue is also tightly related to the (in)stability of the scalar potential. First, we study — in the theoretical setup described above — the parametric behavior of the diphoton signal rate, total width, and one-loop β functions. Then, we numerically solve the renormalization group equations, taking into account the observed diphoton signal rate and total width, to investigate the fate of the weakly coupled theory. We find that — with the only exception of few fine-tuned directions — weakly coupled interpretations of the excess are brought back to a strongly coupled regime if the running is taken into account.
Energy Technology Data Exchange (ETDEWEB)
Treiner, C. (Universite Pierre et Marie Curie, Paris (France)); Nortz, M.; Vaution, C. (Faculte de Pharmacie de Paris-sud, Chatenay-Malabry (France))
1990-07-01
The apparent partition coefficient P of barbituric acids between micelles and water has been determined in mixed binary surfactant solutions from solubility measurements in the whole micellar composition range. The binary systems chosen ranged from the strongly interacting system dodecyltrimethylammonium chloride + sodium dodecyl sulfate to weakly interacting systems such as benzyldimethyltetradecylammonium chloride + tetradecyltrimethyammonium chloride. In all cases studied, mixed micelle formation is unfavorable to micellar solubilization. A correlation is found between the unlike surfactants interaction energy, as measured by the regular solution parameter {beta} and the solute partition coefficient change upon surfactant mixing. By use of literature data on micellar solubilization in binary surfactant solutions, it is shown that the change of P for solutes which are solubilized by surface adsorption is generally governed by the sign and amplitude of the interaction parameter {beta}.
Strong Cation···π Interactions Promote the Capture of Metal Ions within Metal-Seamed Nanocapsule
2015-01-01
Thallium ions are transported to the interior of gallium-seamed pyrogallol[4]arene nanocapsules. In comparison to the capture of Cs ions, the extent of which depends on the type and position of the anion employed in the cesium salt, the enhanced strength of Tl···π vs Cs···π interactions facilitates permanent entrapment of Tl+ ions on the capsule interior. “Stitching-up” the capsule seam with a tertiary metal (Zn, Rb, or K) affords new trimetallic nanocapsules in solid state. PMID:25405777
Czech Academy of Sciences Publication Activity Database
Borunda, M.F.; Liu, X.; Kovalev, A.A.; Liu, X.-J.; Jungwirth, Tomáš; Sinova, J.
2008-01-01
Roč. 78, č. 24 (2008), 245315/1-245315/9 ISSN 1098-0121 R&D Projects: GA MŠk LC510; GA AV ČR KAN400100652; GA ČR GEFON/06/E002 EU Projects: European Commission(XE) 015728 - NANOSPIN Institutional research plan: CEZ:AV0Z10100521 Keywords : Aharonov-Casher effect * spin Hall effect * spin-orbit interaction Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.322, year: 2008
Jiang, Yuzhu; He, Peng; Guan, Xi-Wen
2016-01-01
It was shown [Chin. Phys. Lett. 28, 020503 (2011)] that at zero temperature the ground state of the one-dimensional (1D) $w$-component Fermi gas coincides with that of the spinless Bose gas in the limit $\\omega\\to \\infty$. This behaviour was experimentally evidenced through a quasi-1D tightly trapping ultracold ${}^{173}$Yb atoms in the recent paper [Nature Physics 10, 198 (2014)]. However, understanding of low temperature behaviour of the Fermi gases with a repulsive interaction acquires spi...
A Test of the Flavor Independence of Strong Interactions in e+e- Annihilation at the Z0 Pole
Energy Technology Data Exchange (ETDEWEB)
Muller, David
1999-09-03
This thesis presents a comparison of the strong coupling of the gluons to light (q_{l} = u + d + s), c, and b quarks, determined from multijet rates in flavor-tagged samples of approximately 150,000 hadronic Z^{0} decays recorded with the SLC Large Detector at the SLAC Linear Collider between 1993 and 1995. Flavor separation among primary q_{l} {anti q_{l}} , c{anti c} and b {anti b} final states was made on the basis of the reconstructed mass of long-lived heavy-hadron decay vertices, yielding tags with high purity and low bias against {>=} 3-jet final states. The data obtained imply no flavor dependence within our sensitivity.
International Nuclear Information System (INIS)
Gregori, G.; Hansen, S.B.; Key, M.H.; King, J.; Mackinnon, A.J.; Park, H.; Patel, P.K.; Shepard, R.; Snavely, R.A.; Wilks, S.C.; Glenzer, S.H.
2005-01-01
We have measured high resolution copper Kα spectra from a picosecond high intensity laser produced plasma. By fitting the shape of the experimental spectra with a self-consistent-field model which includes all the relevant line shifts from multiply ionized atoms, we are able to infer time and spatially averaged electron temperatures (T e ) and ionization state (Z) in the foil. Our results show increasing values for T e and Z when the overall mass of the target is reduced. In particular, we measure temperatures in excess of 200 eV with Z ∼ 13-14. For these conditions the ion-ion coupling constant is Λ ii ∼ 8-9, thus suggesting the achievement of a strongly coupled plasma regime
Vafek, Oskar; Chubukov, Andrey V.
2017-02-01
We present a novel mechanism of s -wave pairing in Fe-based superconductors. The mechanism involves holes near dx z/dy z pockets only and is applicable primarily to strongly hole doped materials. We argue that as long as the renormalized Hund's coupling J exceeds the renormalized interorbital Hubbard repulsion U', any finite spin-orbit coupling gives rise to s -wave superconductivity. This holds even at weak coupling and regardless of the strength of the intraorbital Hubbard repulsion U . The transition temperature grows as the hole density decreases. The pairing gaps are fourfold symmetric, but anisotropic, with the possibility of eight accidental nodes along the larger pocket. The resulting state is consistent with the experiments on KFe2 As2 .
Heidmann, T; Changeux, J P
1979-02-15
Preincubation of receptor-rich membrane fragments from Torpedo marmorata with tertiary amine local anesthetics and several toxins such as histrionicotoxin, crotoxin and cerulotoxin, modifies the amplitude and time course of the relaxation processes monitored upon rapid mixing of the membrane fragments with the fluorescent agonist, Dns-C6-Cho. In particular, the amplitude of the rapid relaxation process, which is proportional to the fraction of acetylcholine receptor sites in a high-affinity state, increases; accordingly, the rate constant of the 'slow' and 'intermediate' relaxation processes also increases up to ten times (except with histrionicotoxin) whereas in a higher range of local anesthetic concentrations the rate constant of the 'rapid' relaxation process decreases. The data are accounted for by a two-state model of the acetylcholine regulator, assuming distinct binding sites for cholinergic agonists and local anesthetics and allosteric interactions between these two classes of sites; local anesthetics stabilize the regulator in a high-affinity state for agonists even in the absence of agonist, and modify the rate constants for th interconversions between the low-affinity and high-affinity states. The model accounts for the 'slow' fluorescence increase monitored upon addition of local anesthetics to a suspension of receptor-rich membranes supplemented with trace amounts of Dns-C6-Cho. The effect of local anesthetics on the apparent rate constant of the 'rapid' relaxation process can be accounted for on the basis of an additional low-affinity binding of local anesthetics to the acetylcholine receptor site. Finally the increase of the apparent rate constant of the 'intermediate' relaxation process can be simply accounted for by assuming the existence of a third state, corresponding to the 'active' state, to which local anesthetics bind and block ionic transport.
International Nuclear Information System (INIS)
Olaniyi, B.; Shor, A.; Cheng, S.C.; Dugan, G.; Wu, C.S.
1981-05-01
The effective quadrupole moments Q sub(eff) of the nuclei of 165 Ho, 175 Lu, 176 Lu, 179 Hf and 181 Ta were accurately measured by detecting the pionic atom 5g-4f x-rays of the elements. The spectroscopic quadrupole moments, Q sub(spec), were obtained by correcting Q sub(eff) for nuclear finite size effect, distortion of the pion wave function by the pion-nucleus strong interaction, and contribution to the energy level splittings by the strong interaction. The intrinsic quadrupole moments, Q 0 , were obtained by projecting Q sub(spec) into the frame of reference fixed on the nucleus. The shift, epsilon 0 , and broadening, GAMMA 0 , of the 4f energy level due to the strong interactions between the pion and the nucleons for all the elements were also measured. Theoretical values of epsilon 0 and GAMMA 0 were calculated and compared to the experimental values. The measured values of Q 0 were compared with the existing results in muonic and pionic atoms. The measured values of epsilon 0 and GAMMA 0 were also compared with existing values. (auth)
Romasanta, Pablo N; Curto, Lucrecia M; Sarratea, María B; Noli Truant, Sofía; Antonoglou, María B; Fernández Lynch, María J; Delfino, José M; Mariuzza, Roy A; Fernández, Marisa M; Malchiodi, Emilio L
2017-01-01
Natural killer (NK) cells are lymphocytes of the innate immune system that eliminate virally infected or malignantly transformed cells. NK cell function is regulated by diverse surface receptors that are both activating and inhibitory. Among them, the homodimeric Ly49 receptors control NK cell cytotoxicity by sensing major histocompatibility complex class I molecules (MHC-I) on target cells. Although crystal structures have been reported for Ly49/MHC-I complexes, the underlying binding mechanism has not been elucidated. Accordingly, we carried out thermodynamic and kinetic experiments on the interaction of four NK Ly49 receptors (Ly49G, Ly49H, Ly49I and Ly49P) with two MHC-I ligands (H-2D d and H-2D k ). These Ly49s embrace the structural and functional diversity of the highly polymorphic Ly49 family. Combining surface plasmon resonance, fluorescence anisotropy and far-UV circular dichroism (CD), we determined that the best model to describe both inhibitory and activating Ly49/MHC-I interactions is one in which the two MHC-I binding sites of the Ly49 homodimer present similar binding constants for the two sites (∼10 6 M -1 ) with a slightly positive co-operativity in some cases, and without far-UV CD observable conformational changes. Furthermore, Ly49/MHC-I interactions are diffusion-controlled and enthalpy-driven. These features stand in marked contrast with the activation-controlled and entropy-driven interaction of Ly49s with the viral immunoevasin m157, which is characterized by strong positive co-operativity and conformational selection. These differences are explained by the distinct structures of Ly49/MHC-I and Ly49/m157 complexes. Moreover, they reflect the opposing roles of NK cells to rapidly scan for virally infected cells and of viruses to escape detection using immunoevasins such as m157. © 2017 The Author(s); published by Portland Press Limited on behalf of the Biochemical Society.
Myofilament kinetics in isometric twitch dynamics.
Campbell, K B; Razumova, M V; Kirkpatrick, R D; Slinker, B K
2001-05-01
To better understand the relationship between kinetic processes of contraction and the dynamic features of an isometric twitch, studies were conducted using a mathematical model that included: (1) kinetics of cross bridge (XB) cycling; (2) kinetics of thin filament regulatory processes; (3) serial and feedback interactions between these two kinetic processes; and (4) time course of calcium activation. Isometric twitch wave forms were predicted, morphometric features of the predicted twitch wave form were evaluated, and sensitivities of wave form morphometric features to model kinetic parameters were assessed. Initially, the impulse response of the XB cycle alone was analyzed with the findings that dynamic constants of the twitch transient were much faster than turnover number of steady-state XB cycling, and, although speed and duration of the twitch wave form were sensitive to XB cycle kinetic constants. parameters of wave shape were not. When thin filament regulatory unit (RU) kinetics were added to XB cycle kinetics, the system impulse response was slowed with only little effect on wave shape. When cooperative neighbor interactions between RU and XB were added, twitch wave shape (as well as amplitude, speed and duration) proved to be sensitive to variation in cooperativity. Importantly, persistence and shape of the falling phase could be strongly modified. When kinetic coefficients of XB attachment were made to depend on sarcomere length, changes in wave shape occurred that did not occur when only sliding filament mechanisms were operative. Indeed, the force-length relationship proved to be highly sensitive to length-dependent XB attachment in combination with cooperative interactions. These model findings are the basis of hypotheses for the role of specific kinetic events of contraction in generating twitch wave form features.
Disentangling weak and strong interactions in B → K*(→ Kπ)π Dalitz-plot analyses
Energy Technology Data Exchange (ETDEWEB)
Charles, Jerome [CNRS, Aix-Marseille Univ., Universite de Toulon, CPT UMR 7332, Marseille (France); Descotes-Genon, Sebastien [CNRS, Univ. Paris-Sud, Universite Paris-Saclay, Laboratoire de Physique Theorique (UMR 8627), Orsay (France); Ocariz, Jose [Sorbonne Universites, UPMC Univ. Paris 06, UMR 7585, LPNHE, Paris (France); Universite Paris Diderot, LPNHE UMR 7585, Sorbonne Paris Cite, Paris (France); Perez Perez, Alejandro [Universite de Strasbourg, CNRS, IPHC UMR 7178, Strasbourg (France); Collaboration: For the CKMfitter Group
2017-08-15
Dalitz-plot analyses of B → Kππ decays provide direct access to decay amplitudes, and thereby weak and strong phases can be disentangled by resolving the interference patterns in phase space between intermediate resonant states. A phenomenological isospin analysis of B → K*(→ Kπ)π decay amplitudes is presented exploiting available amplitude analyses performed at the BaBar, Belle and LHCb experiments. A first application consists in constraining the CKM parameters thanks to an external hadronic input. A method, proposed some time ago by two different groups and relying on a bound on the electroweak penguin contribution, is shown to lack the desired robustness and accuracy, and we propose a more alluring alternative using a bound on the annihilation contribution. A second application consists in extracting information on hadronic amplitudes assuming the values of the CKM parameters from a global fit to quark flavour data. The current data yields several solutions, which do not fully support the hierarchy of hadronic amplitudes usually expected from theoretical arguments (colour suppression, suppression of electroweak penguins), as illustrated from computations within QCD factorisation. Some prospects concerning the impact of future measurements at LHCb and Belle II are also presented. Results are obtained with the CKMfitter analysis package, featuring the frequentist statistical approach and using the Rfit scheme to handle theoretical uncertainties. (orig.)
International Nuclear Information System (INIS)
Hamid, M.A.
1994-01-01
The association of porcine trypsin with soybean trypsin inhibitor (Kunitz) resulted in characteristic changes in absorption spectrum, indicating an alteration of the micro environments of the enzyme chromophores as a consequence of the interaction. The rates of formation of the stable trypsin - inhibitor complexes from porcine - alpha - trypsin and soybean trypsin inhibitor and from porcine - beta - trypsin and either intact or modified soybean trypsin inhibitor were measured by mixing the equimolar concentration of the reactants in a Stopped - Flow apparatus at pH (4.5 to 10.0). The reaction of trypsin with soybean trypsin inhibitor was of first order with respect to the concentration of the reactants used. The rates of dissociation of the stable complexes, alpha - trypsin - soybean trypsin inhibitor, beta -trypsin - soybean trypsin inhibitor and beta -trypsin modified soybean trypsin inhibitor were also measured at pH (1.92 to 3.58). The values of first order rate constant, k/sub D/ obtained for the dissociation of all the three complexes were identical with one another. The kinetics results obtained for the porcine trypsin were compared with those of bovine trypsin system and it was suggested that the reaction mechanisms in both these systems were identical. (author)
Strečka, Jozef
2018-01-01
The mixed spin-1/2 and spin-S Ising model on the Union Jack (centered square) lattice with four different three-spin (triplet) interactions and the uniaxial single-ion anisotropy is exactly solved by establishing a rigorous mapping equivalence with the corresponding zero-field (symmetric) eight-vertex model on a dual square lattice. A rigorous proof of the aforementioned exact mapping equivalence is provided by two independent approaches exploiting either a graph-theoretical or spin representation of the zero-field eight-vertex model. An influence of the interaction anisotropy as well as the uniaxial single-ion anisotropy on phase transitions and critical phenomena is examined in particular. It is shown that the considered model exhibits a strong-universal critical behaviour with constant critical exponents when considering the isotropic model with four equal triplet interactions or the anisotropic model with one triplet interaction differing from the other three. The anisotropic models with two different triplet interactions, which are pairwise equal to each other, contrarily exhibit a weak-universal critical behaviour with critical exponents continuously varying with a relative strength of the triplet interactions as well as the uniaxial single-ion anisotropy. It is evidenced that the variations of critical exponents of the mixed-spin Ising models with the integer-valued spins S differ basically from their counterparts with the half-odd-integer spins S.
SN 2011A: A Low-luminosity Interacting Transient with a Double Plateau and Strong Sodium Absorption
de Jaeger, T.; Anderson, J. P.; Pignata, G.; Hamuy, M.; Kankare, E.; Stritzinger, M. D.; Benetti, S.; Bufano, F.; Elias-Rosa, N.; Folatelli, G.; Förster, F.; González-Gaitán, S.; Gutiérrez, C. P.; Inserra, C.; Kotak, R.; Lira, P.; Morrell, N.; Taddia, F.; Tomasella, L.
2015-07-01
We present optical photometry and spectroscopy of the optical transient SN 2011A. Our data span 140 days after discovery including {BVRI} u\\prime g\\prime r\\prime i\\prime z\\prime photometry and 11 epochs of optical spectroscopy. Originally classified as a type IIn supernova (SN IIn) due to the presence of narrow Hα emission, this object shows exceptional characteristics. First, the light curve shows a double plateau, a property only observed before in the impostor SN 1997bs. Second, SN 2011A has a very low luminosity ({M}V=-15.72), placing it between normal luminous SNe IIn and SN impostors. Third, SN 2011A shows low velocity and high equivalent width absorption close to the sodium doublet, which increases with time and is most likely of circumstellar origin. This evolution is also accompanied by a change in line profile; when the absorption becomes stronger, a P Cygni profile appears. We discuss SN 2011A in the context of interacting SNe IIn and SN impostors, which appears to confirm the uniqueness of this transient. While we favor an impostor origin for SN 2011A, we highlight the difficulty in differentiating between terminal and non-terminal interacting transients. This paper includes data obtained with the 6.5 m Magellan Telescopes and du Pont telescope; the Gemini-North Telescope, Mauna Kea, USA (Gemini Program GN-2010B-Q67, PI: Stritzinger); the PROMPT telescopes at Cerro Tololo Inter-American Observatory in Chile; with the Liverpool Telescope operated on the island of La Palma by Liverpool John Moores University in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias with financial support from the UK Science and Technology Facilities Council; based on observations made with the Nordic Optical Telescope, operated by the Nordic Optical Telescope Scientific Association at the Observatorio del Roque de los Muchachos, La Palma, Spain, of the Instituto de Astrofisica de Canarias; the NTT from ESO Science Archive
International Nuclear Information System (INIS)
Konorov, S. O.; Hepburn, J. W.; Milner, V.
2011-01-01
Understanding the effect of strong laser pulses on the evolution of an atomic or molecular wave function is important in the context of coherent control in the strong-field regime, when power broadening and dynamic Stark shifts become comparable with or bigger than the bandwidth of the control field. We experimentally demonstrate the method of complete characterization of a complex-valued amplitude of a quantum state driven by a strong two-photon field. The method is based on coherent scattering of a weak probe pulse from the strong-field-induced atomic coherence, followed by the detection of the time- and frequency-resolved parametric four-wave-mixing signal. We show that the proposed technique corresponds to a cross-correlation frequency-resolved optical gating (XFROG) of the highly perturbed evolution of an atomic quantum state. Utilizing the XFROG retrieval algorithm, we determine both the amplitude and phase of an atomic wave function at any time moment throughout the interaction with the driving field. The direct retrieval of the time-dependent phase of the wave function, rather than the population dynamics only, enables us to observe the strong-field effects with arbitrary time and frequency resolution.
Rybczynski, Maciej; Baatar, B.; Barna, D.; Bartke, J.; Beck, H.; Betev, L.; Bialkowska, H.; Blume, C.; Bogusz, M.; Boimska, B.; Book, J.; Botje, M.; Buncic, P.; Cetner, T.; Christakoglou, P.; Chung, P.; Chvala, O.; Cramer, J.G.; Eckardt, V.; Fodor, Z.; Foka, P.; Friese, V.; Gazdzicki, M.; Grebieszkow, K.; Hohne, C.; Kadija, K.; Karev, A.; Kolesnikov, V.I.; Kowalski, M.; Kresan, D.; Laszlo, A.; Lacey, R.; van Leeuwen, M.; Mackowiak-Pawlowska, M.; Makariev, M.; Malakhov, A.I.; Mateev, M.; Melkumov, G.L.; Mitrovski, M.; Mrowczynski, St.; Nicolic, V.; Palla, G.; Panagiotou, A.D.; Peryt, W.; Pluta, J.; Prindle, D.; Puhlhofer, F.; Renfordt, R.; Roland, C.; Roland, G.; Rybczynski, M.; Rybicki, A.; Sandoval, A.; Schmitz, N.; Schuster, T.; Seyboth, P.; Sikler, F.; Skrzypczak, E.; Slodkowski, M.; Stefanek, G.; Stock, R.; Strobele, H.; Susa, T.; Szuba, M.; Utvic, M.; Varga, D.; Vassiliou, M.; Veres, G.I.; Vesztergombi, G.; Vranic, D.; Wlodarczyk, Z.; Wojtaszek-Szwarc, A.
2013-01-01
The exploration of the QCD phase diagram particularly the search for a phase transition from hadronic to partonic degrees of freedom and possibly a critical endpoint, is one of the most challenging tasks in present heavy-ion physics. As observed by the NA49 experiment, several hadronic observables in central Pb+Pb collisions at the CERN SPS show qualitative changes in their energy dependence. These features are not observed in elementary interactions and indicate the onset of a phase transition in the SPS energy range. The existence of a critical point is expected to result in the increase of event-by-event fluctuations of various hadronic observables provided that the freeze-out of the measured hadrons occurs close to its location in the phase diagram and the evolution of the final hadron phase does not erase the fluctuations signals. A selection of NA49 results on di-pion and proton intermittency from the scan of the phase diagram will be discussed.
Rybczyński, Maciej
2014-01-01
The exploration of the QCD phase diagram particularly the search for a phase transition from hadronic to partonic degrees of freedom and possibly a critical endpoint, is one of the most challenging tasks in present heavy-ion physics. As observed by the NA49 experiment, several hadronic observables in central Pb+Pb collisions at the CERN SPS show qualitative changes in their energy dependence. These features are not observed in elementary interactions and indi- cate the onset of a phase transition in the SPS energy range. The existence of a critical point is expected to result in the increase of event-by-event fluctuations of various hadronic observables provided that the freeze-out of the measured hadrons occurs close to its location in the phase di- agram and the evolution of the final hadron phase does not erase the fluctuations signals. Further information about the existence and nature of a phase transition in the SPS energy range can be gained from the studies of event-by-event fluctuations of final stat...
Carleo, Giuseppe; Cevolani, Lorenzo; Sanchez-Palencia, Laurent; Holzmann, Markus
2017-07-01
We introduce the time-dependent variational Monte Carlo method for continuous-space Bose gases. Our approach is based on the systematic expansion of the many-body wave function in terms of multibody correlations and is essentially exact up to adaptive truncation. The method is benchmarked by comparison to an exact Bethe ansatz or existing numerical results for the integrable Lieb-Liniger model. We first show that the many-body wave function achieves high precision for ground-state properties, including energy and first-order as well as second-order correlation functions. Then, we study the out-of-equilibrium, unitary dynamics induced by a quantum quench in the interaction strength. Our time-dependent variational Monte Carlo results are benchmarked by comparison to exact Bethe ansatz results available for a small number of particles, and are also compared to quench action results available for noninteracting initial states. Moreover, our approach allows us to study large particle numbers and general quench protocols, previously inaccessible beyond the mean-field level. Our results suggest that it is possible to find correlated initial states for which the long-term dynamics of local density fluctuations is close to the predictions of a simple Boltzmann ensemble.
Rączka, P.; Dubois, J.-L.; Hulin, S.; Tikhonchuk, V.; Rosiński, M.; Zaraś-Szydłowska, A.; Badziak, J.
2017-12-01
Measurements are reported of the target neutralization current, the target charge, and the tangential component of the magnetic field generated as a result of laser-target interaction by pulses with the energy in the range of 45 mJ to 92 mJ on target and the pulse duration from 39 fs to 1000 fs. The experiment was performed at the Eclipse facility in CELIA, Bordeaux. The aim of the experiment was to extend investigations performed for the thick (mm scale) targets to the case of thin (micrometer thickness) targets in a way that would allow for a straightforward comparison of the results. We found that thin foil targets tend to generate 20 to 50 percent higher neutralization current and the target charge than the thick targets. The measurement of the tangential component of the magnetic field had shown that the initial spike is dominated by the 1 ns pulse consistent with the 1 ns pulse of the neutralization current, but there are some differences between targets of different type on sub-ns scale, which is an effect going beyond a simple picture of the target acting as an antenna. The sub-ns structure appears to be reproducible to surprising degree. We found that there is in general a linear correlation between the maximum value of the magnetic field and the maximum neutralization current, which supports the target-antenna picture, except for pulses hundreds of fs long.
Wang, Jihong; Palzkill, Timothy; Chow, Dar-Chone
2009-01-02
In a previous study, we examined thermodynamic parameters for 20 alanine mutants in beta-lactamase inhibitory protein (BLIP) for binding to TEM-1 beta-lactamase. Here we have determined the structures of two thermodynamically distinctive complexes of BLIP mutants with TEM-1 beta-lactamase. The complex BLIP Y51A-TEM-1 is a tight binding complex with the most negative binding heat capacity change (DeltaG = approximately -13 kcal mol(-1) and DeltaCp = approximately -0.8 kcal mol(-1) K(-1)) among all of the mutants, whereas BLIP W150A-TEM-1 is a weak complex with one of the least negative binding heat capacity changes (DeltaG = approximately -8.5 kcal mol(-1) and DeltaCp = approximately -0.27 kcal mol(-1) K(-1)). We previously determined that BLIP Tyr51 is a canonical and Trp150 an anti-canonical TEM-1-contact residue, where canonical refers to the alanine substitution resulting in a matched change in the hydrophobicity of binding free energy. Structure determination indicates a rearrangement of the interactions between Asp49 of the W150A BLIP mutant and the catalytic pocket of TEM-1. The Asp49 of W150A moves more than 4 angstroms to form two new hydrogen bonds while losing four original hydrogen bonds. This explains the anti-canonical nature of the Trp150 to alanine substitution, and also reveals a strong long distance coupling between Trp150 and Asp49 of BLIP, because these two residues are more than 25 angstroms apart. Kinetic measurements indicate that the mutations influence the dissociation rate but not the association rate. Further analysis of the structures indicates that an increased number of interface-trapped water molecules correlate with poor interface packing in a mutant. It appears that the increase of interface-trapped water molecules is inversely correlated with negative binding heat capacity changes.
Energy Technology Data Exchange (ETDEWEB)
Alcaraz, Francisco Castilho
1977-07-01
Using the propagator's technique in the grand ensemble developed by Montroll and Ward we investigate the magnetic properties of an interacting electron gas in a strong magnetic field. The free propagator properly constructed shows that the spin paramagnetism does not have a term with strong temperature dependence, contrary to the result of Isihara. Considering the electron density to be constant, the dHVA oscillations in the magnetic susceptibility and sound velocity, considering the effects of first exchange interactions, show only one phase in agreement with experimental result, while Ichimura and Isihara obtained two phases differing by {pi}/2. The effects of first order exchange interactions in the dHVA oscillations of the magnetic susceptibility and sound velocity give rise to an exponential factor in the amplitudes of oscillator (Dingle factor), being the Dingle temperature linearly dependent of the Fermi velocity. The calculations of the ring diagram contribution to the grand partition function, show that the approximation used by Isihara for this calculations is not good and the dHVA oscillations of the contributions from the ring diagrams for the grand partition function have a phase differing by {pi}/2 from that obtained by Isihara. (author)
Energy Technology Data Exchange (ETDEWEB)
Andreev, Pavel A., E-mail: andreevpa@physics.msu.ru [Faculty of Physics, Lomonosov Moscow State University, Moscow (Russian Federation)
2015-06-15
We discuss the complete theory of spin-1/2 electron-positron quantum plasmas, when electrons and positrons move with velocities mach smaller than the speed of light. We derive a set of two fluid quantum hydrodynamic equations consisting of the continuity, Euler, spin (magnetic moment) evolution equations for each species. We explicitly include the Coulomb, spin-spin, Darwin and annihilation interactions. The annihilation interaction is the main topic of the paper. We consider the contribution of the annihilation interaction in the quantum hydrodynamic equations and in the spectrum of waves in magnetized electron-positron plasmas. We consider the propagation of waves parallel and perpendicular to an external magnetic field. We also consider the oblique propagation of longitudinal waves. We derive the set of quantum kinetic equations for electron-positron plasmas with the Darwin and annihilation interactions. We apply the kinetic theory to the linear wave behavior in absence of external fields. We calculate the contribution of the Darwin and annihilation interactions in the Landau damping of the Langmuir waves. We should mention that the annihilation interaction does not change number of particles in the system. It does not related to annihilation itself, but it exists as a result of interaction of an electron-positron pair via conversion of the pair into virtual photon. A pair of the non-linear Schrodinger equations for the electron-positron plasmas including the Darwin and annihilation interactions is derived. Existence of the conserving helicity in electron-positron quantum plasmas of spinning particles with the Darwin and annihilation interactions is demonstrated. We show that the annihilation interaction plays an important role in the quantum electron-positron plasmas giving the contribution of the same magnitude as the spin-spin interaction.
Experimental evidence of the decrease of kinetic energy of hadrons in passing through atomic nuclei
Strugalski, Z.
1985-01-01
Hadrons with kinetic energies higher than the pion production threshold lose their kinetic energies monotonically in traversing atomic nuclei, due to the strong interactions in nuclear matter. This phenomenon is a crude analogy to the energy loss of charged particles in their passage through materials. Experimental evidence is presented.
Boudreau, Thomas F; Peck, Gregory M; O'Keefe, Sean F; Stewart, Amanda C
2017-01-01
Fungicide residues on fruit may adversely affect yeast during cider fermentation, leading to sluggish or stuck fermentation or the production of hydrogen sulfide (H 2 S), which is an undesirable aroma compound. This phenomenon has been studied in grape fermentation but not in apple fermentation. Low nitrogen availability, which is characteristic of apples, may further exacerbate the effects of fungicides on yeast during fermentation. The present study explored the effects of three fungicides: elemental sulfur (S 0 ) (known to result in increased H 2 S in wine); fenbuconazole (used in orchards but not vineyards); and fludioxonil (used in post-harvest storage of apples). Only S 0 led to increased H 2 S production. Fenbuconazole (≥0.2 mg L -1 ) resulted in a decreased fermentation rate and increased residual sugar. An interactive effect of yeast assimilable nitrogen (YAN) concentration and fenbuconazole was observed such that increasing the YAN concentration alleviated the negative effects of fenbuconazole on fermentation kinetics. Cidermakers should be aware that residual fenbuconazole (as low as 0.2 mg L -1 ) in apple juice may lead to stuck fermentation, especially when the YAN concentration is below 250 mg L -1 . These results indicate that fermentation problems attributed to low YAN may be caused or exacerbated by additional factors such as fungicide residues, which have a greater impact on fermentation performance under low YAN conditions. © 2016 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. © 2016 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
Raseda, Nasrin; Hong, Soonho; Kwon, O Yul; Ryu, Keungarp
2014-12-28
The interactive inhibitory effects of pH and chloride on the catalysis of laccase from Trametes versicolor were investigated by studying the alteration of inhibition characteristics of sodium chloride at different pHs for the oxidation of 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid). At pH 3.0, the addition of sodium chloride (50 mM) brought about a 40-fold increase in Km(app) and a 4-fold decrease in Vmax(app). As the pH increased to 7.0, the inhibitory effects of sodium chloride became significantly weakened. The mixed-inhibition mechanism was successfully used to quantitatively estimate the competitive and uncompetitive inhibition strengths by chloride at two different pHs (pH 3.0 and 6.0). At pH 3.0, the competitive inhibition constant, Ki, was 0.35 mM, whereas the uncompetitive inhibition constant, Ki', was 18.1 mM, indicating that the major cause of the laccase inhibition by chloride is due to the competitive inhibition step. At a higher pH of 6.0, where the inhibition of the laccase by hydroxide ions takes effect, the inhibition of the laccase by chloride diminished to a great extent, showing increased values of both the competitive inhibition constant (Ki= 23.7 mM) and uncompetitive inhibition constant (Ki' = 324 mM). These kinetic results evidenced that the hydroxide anion and chloride share a common mechanism to inhibit the laccase activity.
Lipatov, A. S.; Cooper, J F.; Paterson, W. R.; Sittler, E. C., Jr.; Hartle, R. E.; Simpson, David G.
2013-01-01
The hybrid kinetic model supports comprehensive simulation of the interaction between different spatial and energetic elements of the Europa moon-magnetosphere system with respect to a variable upstream magnetic field and flux or density distributions of plasma and energetic ions, electrons, and neutral atoms. This capability is critical for improving the interpretation of the existing Europa flyby measurements from the Galileo Orbiter mission, and for planning flyby and orbital measurements (including the surface and atmospheric compositions) for future missions. The simulations are based on recent models of the atmosphere of Europa (Cassidy et al., 2007; Shematovich et al., 2005). In contrast to previous approaches with MHD simulations, the hybrid model allows us to fully take into account the finite gyroradius effect and electron pressure, and to correctly estimate the ion velocity distribution and the fluxes along the magnetic field (assuming an initial Maxwellian velocity distribution for upstream background ions). Photoionization, electron-impact ionization, charge exchange and collisions between the ions and neutrals are also included in our model. We consider the models with Oþ þ and Sþ þ background plasma, and various betas for background ions and electrons, and pickup electrons. The majority of O2 atmosphere is thermal with an extended non-thermal population (Cassidy et al., 2007). In this paper, we discuss two tasks: (1) the plasma wake structure dependence on the parameters of the upstream plasma and Europa's atmosphere (model I, cases (a) and (b) with a homogeneous Jovian magnetosphere field, an inductive magnetic dipole and high oceanic shell conductivity); and (2) estimation of the possible effect of an induced magnetic field arising from oceanic shell conductivity. This effect was estimated based on the difference between the observed and modeled magnetic fields (model II, case (c) with an inhomogeneous Jovian magnetosphere field, an inductive
Angelopoulos, Angelos; Backenstoss, Gerhard; Bargassa, P; Behnke, O; Benelli, A; Bertin, V; Blanc, F; Bloch, P; Carlson, P J; Carroll, M; Cawley, E; Chertok, M B; Danielsson, M; Dejardin, M; Derré, J; Ealet, A; Eleftheriadis, C; Fetscher, W; Fidecaro, Maria; Filipcic, A; Francis, D; Fry, J; Gabathuler, Erwin; Gamet, R; Gerber, H J; Go, A; Haselden, A; Haymen, P J; Henry-Coüannier, F; Hollander, R W; Jon-And, K; Kettle, P R; Kokkas, P; Kreuger, R; Le Gac, R; Leimgruber, F; Mandic, I; Manthos, N; Marel, Gérard; Mikuz, M; Miller, J; Montanet, François; Müller, A; Nakada, Tatsuya; Pagels, B; Papadopoulos, I M; Pavlopoulos, P; Polivka, G; Rickenbach, R; Roberts, B L; Ruf, T; Sakelliou, L; Schäfer, M; Schaller, L A; Schietinger, T; Schopper, A; Tauscher, Ludwig; Thibault, C; Touchard, F; Touramanis, C; van Eijk, C W E; Vlachos, S; Weber, P; Wigger, O; Wolter, M; Zavrtanik, D; Zimmerman, D
2001-01-01
The CPLEAR set-up (modified) has been used to determine the K/sub L/- K/sub S/ mass difference by a method where neutral-kaon strangeness oscillations are monitored through kaon strong interactions, rather than semileptonic decays, thus requiring no assumptions on CPT invariance for the decay amplitudes. The result, Delta m= (0.5343+or-0.0063/sub stat/+or-0.0025/sub syst/)*10/sup 10/ h(cross) /s, provides a valuable input for CPT tests. (22 refs).
Park, Sarah S; Hendon, Christopher H; Fielding, Alistair J; Walsh, Aron; O'Keeffe, Michael; Dincă, Mircea
2017-03-15
The structure-directing role of the inorganic secondary building unit (SBU) is key for determining the topology of metal-organic frameworks (MOFs). Here we show that organic building units relying on strong π interactions that are energetically competitive with the formation of common inorganic SBUs can also play a role in defining the topology. We demonstrate the importance of the organic SBU in the formation of Mg 2 H 6 (H 3 O)(TTFTB) 3 (MIT-25), a mesoporous MOF with the new ssp topology. A delocalized electronic hole is critical in the stabilization of the TTF triad organic SBUs and exemplifies a design principle for future MOF synthesis.
Directory of Open Access Journals (Sweden)
B BOUHAFS
2003-12-01
Full Text Available The attractive potential energy between the atoms of rubidium vapor and a dielectric wall has been investigated by monitoring the reflection light at the interface. The atom- wall interaction potential of the form V(z = - C /z3 (z: atom-wall allows to predict experimental results only for weak regime, i.e., where C<< 0.2 kHzmm3. In the strong interaction case, the dispersive line shape is turned into an absorption-type line shape. The influence of atomic density on the shift of the selective reflection resonance relatively to the frequency of unperturbed atomic transition is found to be red with a negative slope. This technique opens the way to characterize the windows made of different materials thin films.
International Nuclear Information System (INIS)
Kura, H; Takahashi, M; Ogawa, T
2011-01-01
High-volume fraction α-Fe nanoparticle (NP) agglomerates were prepared using chemically synthesized NPs. In the agglomerate, NPs are separated by surfactant and NP superlattice with a hexagonal close-packed structure is locally realized. Volume fractions of NPs at 20% and 42% were obtained in agglomerates consisting of 2.9 nm and 8.2 nm diameter NPs, respectively. The high saturation magnetization of α-Fe NPs and high volume fraction of NPs in the agglomerate provide strong magnetic dipole-dipole interaction. The interaction energy of the agglomerate became much larger than the anisotropic energy of individual NPs. As a result, the blocking temperature of the 8.2 nm NP agglomerate was significantly enhanced from 52.2 K to around 500 K. (fast track communication)
M. Ammann; U. Pöschl
2007-01-01
International audience; A kinetic model framework with consistent and unambiguous terminology and universally applicable rate equations and parameters for aerosol and cloud surface chemistry and gas-particle interactions has been presented in the preceding companion paper by Pöschl, Rudich and Ammann (Pöschl et al., 2005), abbreviated PRA. It allows to describe mass transport and chemical reaction at the gas-particle interface and to link aerosol and cloud surface processes with gas phase and...
Aisina, R B; Mukhametova, L I; Gulin, D A; Gershkovich, K B; Varfolomeyev, S D
2015-01-01
Comparative in vitro study of the kinetics of various reactions involved in the process of thrombolysis initiated by streptokinase (SK) and staphylokinase (STA) was carried out. It was shown that at the interaction of an equimolar ratio of plasminogen (Pg) with SK or STA the rate of formation and the specific esterase activity of the complex plasmin (Pm) · SK are higher than those of the complex Pm · STA. The catalytic efficiency (kcat/Km) of hydrolysis of the chromogenic plasmin substrates by Pm · SK complex was 2 times higher than by Pm · STA complex. In the absence of fibrin catalytic efficiency (kPg/K(Pg)) of activation of Glu-plasminogen and Lys-plasminogen glycoform II by Pm · SK complex was higher than by Pm · STA complex, but the pres- ence of fibrin increased kPg/K(Pg)) activation of both plasminogens by Pm · STA complex significantly stronger than by Pm · SK complex due to the decrease in K(Pg)). In contrast to STA (15.5 kDa), SK molecule (47 kDa) creates significant steric hindrances for the interaction of plasmin in Pm · SK complex with protein inhibi- tors. In addition, SK caused greater fibrinogen degradation than STA. It is shown that Pm · SK and Pm · STA complexes lyse fibrin clots in buffer with similar rates, while the rate of lysis of plasma clots, immersed in plas- ma, by Pm · STA complex are significantly higher than those by Pm · SK complex. It was revealed that the species specificity of STA and S K is determined mainly by the rate of formation and the efficiency of Pm · SK and Pm · STA complexes in the activation of autologous plasminogen. The lysis efficiency of plasma clots of mammals fell in the series: human > dog > rabbit for SK and the dog > human > rabbit for STA. The results show that in the purified system SK is a more effective activator of plasminogen than STA. In the system con- taining fibrin and α2-AP, the activator and fibrinolytic activities of STA are higher than those of SK, due to the increased stability in
Strongly interacting matter under rotation
Jiang, Yin; Lin, Zi-Wei; Huang, Xu-Guang; Liao, Jinfeng
2018-02-01
The vorticity-driven effects are systematically studied in various aspects. With AMPT the distributions of vorticity has been investigated in heavy ion collisions with different collision parameters. Taking the rotational polarization effect into account a generic condensate suppression mechanism is discussed and quantitatively studied with NJL model. And in chiral restored phase the chiral vortical effects would generate a new collective mode, i.e. the chiral vortical wave. Using the rotating quark-gluon plasma in heavy ion collisions as a concrete example, we show the formation of induced flavor quadrupole in QGP and estimate the elliptic flow splitting effect for Λ baryons.
Strongly interacting matter under rotation
Directory of Open Access Journals (Sweden)
Jiang Yin
2018-01-01
Full Text Available The vorticity-driven effects are systematically studied in various aspects. With AMPT the distributions of vorticity has been investigated in heavy ion collisions with different collision parameters. Taking the rotational polarization effect into account a generic condensate suppression mechanism is discussed and quantitatively studied with NJL model. And in chiral restored phase the chiral vortical effects would generate a new collective mode, i.e. the chiral vortical wave. Using the rotating quark-gluon plasma in heavy ion collisions as a concrete example, we show the formation of induced flavor quadrupole in QGP and estimate the elliptic flow splitting effect for Λ baryons.
Strong interaction at finite temperature
Indian Academy of Sciences (India)
Saha Institute of Nuclear Physics, 1/AF, Bidhan Nagar, Kolkata 700 064, India. Abstract. We review two ... tem, from which its energy density, pressure etc. can be obtained. But to describe the heavy-ion ... quantity follows the same steps as for its vacuum counterpart, with the replacement of free vacuum propagators by free ...
Strong interaction at finite temperature
Indian Academy of Sciences (India)
The ﬁrst one is the general method of chiral perturbation theory, which may be readily applied to this problem. The other is the method of thermal QCD sum rules. We show that, when the spectral sides of the sum rules are calculated correctly, they do not lead to any new results, but reproduce those of the vacuum sum rules.
Li, Siwei; Xu, Yao; Chen, Yifu; Li, Weizhen; Lin, Lili; Li, Mengzhu; Deng, Yuchen; Wang, Xiaoping; Ge, Binghui; Yang, Ce; Yao, Siyu; Xie, Jinglin; Li, Yongwang; Liu, Xi; Ma, Ding
2017-08-28
A one-step ligand-free method based on an adsorption-precipitation process was developed to fabricate iridium/cerium oxide (Ir/CeO 2 ) nanocatalysts. Ir species demonstrated a strong metal-support interaction (SMSI) with the CeO 2 substrate. The chemical state of Ir could be finely tuned by altering the loading of the metal. In the carbon dioxide (CO 2 ) hydrogenation reaction it was shown that the chemical state of Ir species-induced by a SMSI-has a major impact on the reaction selectivity. Direct evidence is provided indicating that a single-site catalyst is not a prerequisite for inhibition of methanation and sole production of carbon monoxide (CO) in CO 2 hydrogenation. Instead, modulation of the chemical state of metal species by a strong metal-support interaction is more important for regulation of the observed selectivity (metallic Ir particles select for methane while partially oxidized Ir species select for CO production). The study provides insight into heterogeneous catalysts at nano, sub-nano, and atomic scales. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
Energy Technology Data Exchange (ETDEWEB)
Wang, Yan [Univ. of Tennessee, Knoxville, TN (United States); Rademaker, Louk [Univ. of California, Santa Barbara, CA (United States); Dagotto, Elbio R. [Univ. of Tennessee, Knoxville, TN (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Johnston, Steven [Univ. of Tennessee, Knoxville, TN (United States)
2017-08-18
Here, the discovery of an enhanced superconducting transition temperature T_{c} in monolayers of FeSe grown on several oxide substrates has opened a new route to high-T_{c} superconductivity through interface engineering. One proposal for the origin of the observed enhancement is an electronphonon (e-ph) interaction across the interface that peaked at small momentum transfers. In this paper, we examine the implications of such a coupling on the phononic properties of the system. We show that a strong forward scattering leads to a sizable broadening of phonon lineshape, which may result in charge instabilities at long-wavelengths. However, we further find that the inclusion of Coulombic screening significantly reduces the phonon broadening. Our results show that one might not expect anomalously broad phonon linewidths in the FeSe interface systems, despite the fact that the e-ph interaction has a strong peak in the forward scattering (small \\bfq ) direction.
Ocampo-Torres, F. J.; García-Nava, H.; Durazo, R.; Osuna, P.; Díaz Méndez, G. M.; Graber, H. C.
2011-03-01
The Gulf of Tehuantepec air-sea interaction experiment ( intOA) took place from February to April 2005, under the Programme for the Study of the Gulf of Tehuantepec (PEGoT, Spanish acronym for Programa para el Estudio del Golfo de Tehuantepec). PEGoT is underway aiming for better knowledge of the effect of strong and persistent offshore winds on coastal waters and their natural resources, as well as performing advanced numerical modelling of the wave and surface current fields. One of the goals of the intOA experiment is to improve our knowledge on air-sea interaction processes with particular emphasis on the effect of surface waves on the momentum flux for the characteristic and unique conditions that occur when strong Tehuano winds blow offshore against the Pacific Ocean long period swell. For the field campaign, an air-sea interaction spar (ASIS) buoy was deployed in the Gulf of Tehuantepec to measure surface waves and the momentum flux between the ocean and the atmosphere. High frequency radar systems (phase array type) were in operation from two coastal sites and three acoustic Doppler current profilers were deployed near-shore. Synthetic aperture radar images were also acquired as part of the remote sensing component of the experiment. The present paper provides the main results on the wave and wind fields, addressing the direct calculation of the momentum flux and the drag coefficient, and gives an overview of the intOA experiment. Although the effect of swell has been described in recent studies, this is the first time for the very specific conditions encountered, such as swell persistently opposing offshore winds and locally generated waves, to show a clear evidence of the influence on the wind stress of the significant steepness of swell waves.
Ma, Quanli; Pavlov, Evgeny; Britvina, Tatiana; Zamponi, Gerald W; French, Robert J
2008-11-01
R13X derivatives of mu-conotoxin GIIIA bind externally to single sodium channels and block current incompletely with mean "blocked" durations of several seconds. We studied interactions between two classes of blockers (mu-conotoxins and amines) by steady state, kinetic analysis of block of BTX-modified Na channels in planar bilayers. The amines cause all-or-none block at a site internal to the selectivity filter. TPrA and DEA block single Na channels with very different kinetics. TPrA induces discrete, all-or-none, blocked events (mean blocked durations, approximately 100 ms), whereas DEA produces a concentration-dependent reduction of the apparent single channel amplitude ("fast" block). These distinct modes of action allow simultaneous evaluation of block by TPrA and DEA, showing a classical, competitive interaction between them. The apparent affinity of TPrA decreases with increasing [DEA], based on a decrease in the association rate for TPrA. When an R13X mu-conotoxin derivative and one of the amines are applied simultaneously on opposite sides of the membrane, a mutually inhibitory interaction is observed. Dissociation constants, at +50 mV, for TPrA ( approximately 4 mM) and DEA ( approximately 30 mM) increase by approximately 20%-50% when R13E (nominal net charge, +4) or R13Q (+5) is bound. Analysis of the slow blocking kinetics for the two toxin derivatives showed comparable decreases in affinity of the mu-conotoxins in the presence of an amine. Although this mutual inhibition seems to be qualitatively consistent with an electrostatic interaction across the selectivity filter, quantitative considerations raise questions about the mechanistic details of the interaction.
International Nuclear Information System (INIS)
Trifonov, A.Z.; Kuzmanova, R.B.; Stefanova, R.; Shishedjiev, B.K.
1983-01-01
An approach is offered for determining the reaction rate constant (k) between two liquid substances, the one penetrating into the other. The procedure is based on the experimental measurement of the diffusion coefficient (D). As model reaction the isotopic exchange process in the ketone octanone-2 molecule is chosen, whose active hydrogen atoms undergo deuteration by the strong base trioctyl-methyl-ammonium deuteroxide (TOMA-OD). The diffusion coefficient of the penetrating TOMA-OD, when this reaction takes place, and the rate constant of the latter are determined by an attenuated total reflection (ATR) spectroscopic method on the grounds of appropriate mathematical modeling. The application of this simple and comparatively rapid approach results in the k-value of 1.04x10 -2 sec -1 for the monomolecular interaction mentioned above. The reasons for such an assumption arise from the only initial process stage treatment, where the reactant (TOMA-OD) particles enter the substrate (the ketone) surrounded by an excess of its own molecules. This further allows an analytical solution of the resulting diffusion problem. (orig.) [de
Dudin, G. N.; Ledovskiy, A. V.
2013-06-01
The flow in a spatial hypersonic laminar boundary layer on a planar wing with a point of inflection in the leading edge is considered in the regime of strong viscous-inviscid interaction. The boundary problems are formulated for two cases: self-similar flow near the point of inflection of the leading edge and full three-dimensional (3D) boundary layer on a wing with variable sweep angle. The numerical solution is obtained using the finite-difference method. The results of parametric calculations of influence of a wing shape and the temperature factor on flow characteristics in the boundary layer are presented. The possibility of formation of local regions with high shear stress and heat flux is shown.
DEFF Research Database (Denmark)
Marchukov, O. V.; Eriksen, E. H.; Midtgaard, J. M.
2016-01-01
One-dimensional multi-component Fermi or Bose systems with strong zero-range interactions can be described in terms of local exchange coefficients and mapping the problem into a spin model is thus possible. For arbitrary external confining potentials the local exchanges are given by highly non...... to the computational complexity of the high-dimensional integrals involved. An approach using the local density approximation would therefore be a most welcome approximation due to its simplicity. Here we assess the accuracy of the local density approximation by going beyond the simple harmonic oscillator that has...... been the focus of previous studies and consider some double-wells of current experimental interest. We find that the local density approximation works quite well as long as the potentials resemble harmonic wells but break down for larger barriers. In order to explore the consequences of applying...
Numata, Munenori; Kozawa, Tomohiro
2014-05-19
Self-assembly of porphyrin molecules can be controlled kinetically to form structures with lengths extending from the nano- to the micrometer scale, through a programmed solvent-diffusion process in designed microflow spaces. Temporal solvent structures generated in the microflow were successfully transcribed into molecular architectures. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Detailed kinetic analysis of the interaction between the FOXO4–DNA-binding domain and DNA
Czech Academy of Sciences Publication Activity Database
Vácha, P.; Zusková, Iva; Bumba, Ladislav; Večeř, J.; Obšilová, Veronika; Obšil, T.
2013-01-01
Roč. 184, DEC 31 (2013), s. 68-78 ISSN 0301-4622 R&D Projects: GA ČR(CZ) GAP207/11/0717 Institutional support: RVO:67985823 ; RVO:61388971 Keywords : binding kinetics * DNA-binding domain * FOXO4 forkhead transcription factor Subject RIV: BO - Biophysics; CE - Biochemistry (MBU-M) Impact factor: 2.319, year: 2013
Gaona, Jaime; Lewandowski, Jörg
2017-04-01
The quantification of groundwater-surface water interactions is not only required for budgets but also for an understanding of the complex relations between hyporheic exchange flows (HEF) and the associated chemical and biological processes that take place in hyporheic zones (HZ). Thus, there is a strong need to improve methods for flux estimation.The present study aims to quantify the vertical fluxes across the riverbed from data of temperature depth profiles recorded at the River Schlaube in East Brandenburg, Germany. In order to test the capabilities and limitations of existing methods, fluxes were calculated with an analytical (VFLUX, based on the amplitude attenuation and phase shift analysis) and a numerical (1DTempPro, parametrization based on observed values) approach for heat conduction. We conclude that the strong limitations of the flux estimates are caused by thermal and hydraulic heterogeneities of the sediment properties. Consequently, upscaling of fluxes must include other thermal techniques able to portray the spatial variability of thermal patterns, along with further developments of methods to link thermal depth profiles, thermal patterns of the surface of the streambed and all the other factors involved. Considering time and costs of temperature depth profiles of riverbeds, and the need for multiple devices to cover larger areas, it is additionally tested whether vertical fluxes can be infered from the uppermost temperature sensors of a data set. That would ease hyporheic investigations at larger scales.
International Nuclear Information System (INIS)
Garcia, E.A.; Denis, A.
1990-01-01
A description is made of the chemical interaction between Inconel spacing grids and the Zircaloy of the sheaths. Experiments performed at 1000, 1100 and 1200 deg C with base Zircaloy and with a previously formed layer of ZrO 2 , show that the kinetics is parabolic. The difference between both types of experiments is that the oxide layer delays the initiation of the Inconel-Zry interaction. A model is presented, for the description of the solid/solid interaction, which leads to the formation of eutectic that is liquid at the experiment temperature. Also a model, which represents the oxide layer dissolution and predicts the instant in which it disappears completely, is presented. (Author) [es
International Nuclear Information System (INIS)
Hurley, Caitlin-Mae
2015-01-01
In France all of the nuclear power plant facilities in service today are pressurized water reactors (PWR). Some parts of the PWR in contact with the primary circuit medium, such as the steam generator tubes (fabricated in nickel base alloy A600) and some reactor core internal components (fabricated in stainless steel 316L), can fall victim to environmental degradation phenomena such as stress corrosion cracking (SCC). In the late 1950's, H. Coriou observed experimentally and predicted this type of cracking in alloys traditionally renowned for their SCC resistance (A600). Just some 20 to 30 years later his predictions became a reality. Since then, numerous studies have focused on the description and comprehension of the SCC phenomenon in primary water under reactor operating conditions. In view of reactor lifetime extension, it has become both critical and strategic to be capable of simulating SCC phenomenon in order to optimize construction materials, operating conditions, etc. and to understand the critical parameters in order to limit the damage done by SCC. This study focuses on the role hydrogen plays in SCC phenomenon and in particular H-material interactions. Hydrogen, from primary medium in the form of dissolved H gas or H from the water, can be absorbed by the alloy during the oxidation process taking place under reactor operating conditions. Once absorbed, hydrogen may be transported across the material, diffusing in the interstitial sites of the crystallographic structure and interacting with local defects, such as dislocations, precipitates, vacancies, etc. The presence of these [local defect] sites can slow the hydrogen transport and may provoke local H accumulation in the alloy. This accumulation could modify the local mechanical properties of the material and favor premature rupture. It is therefore essential to identify the nature of these H-material interactions, specifically the rate of H diffusion and hydrogen trapping kinetics at these
González-Durruthy, Michael; Werhli, Adriano V; Seus, Vinicius; Machado, Karina S; Pazos, Alejandro; Munteanu, Cristian R; González-Díaz, Humberto; Monserrat, José M
2017-10-16
The current molecular docking study provided the Free Energy of Binding (FEB) for the interaction (nanotoxicity) between VDAC mitochondrial channels of three species (VDAC1-Mus musculus, VDAC1-Homo sapiens, VDAC2-Danio rerio) with SWCNT-H, SWCNT-OH, SWCNT-COOH carbon nanotubes. The general results showed that the FEB values were statistically more negative (p (SWCNT-VDAC1-Mus musculus) > (SWCNT-VDAC1-Homo sapiens) > (ATP-VDAC). More negative FEB values for SWCNT-COOH and OH were found in VDAC2-Danio rerio when compared with VDAC1-Mus musculus and VDAC1-Homo sapiens (p r 2 > 0.97) was observed between n-Hamada index and VDAC nanotoxicity (or FEB) for the zigzag topologies of SWCNT-COOH and SWCNT-OH. Predictive Nanoparticles-Quantitative-Structure Binding-Relationship models (nano-QSBR) for strong and weak SWCNT-VDAC docking interactions were performed using Perturbation Theory, regression and classification models. Thus, 405 SWCNT-VDAC interactions were predicted using a nano-PT-QSBR classifications model with high accuracy, specificity, and sensitivity (73-98%) in training and validation series, and a maximum AUROC value of 0.978. In addition, the best regression model was obtained with Random Forest (R 2 of 0.833, RMSE of 0.0844), suggesting an excellent potential to predict SWCNT-VDAC channel nanotoxicity. All study data are available at https://doi.org/10.6084/m9.figshare.4802320.v2 .
Miller, A. A.; Cao, Y.; Piro, A. L.; Blagorodnova, N.; Bue, B. D.; Cenko, S. B.; Dhawan, S.; Ferretti, R.; Fox, O. D.; Fremling, C.; Goobar, A.; Howell, D. A.; Hosseinzadeh, G.; Kasliwal, M. M.; Laher, R. R.; Lunnan, R.; Masci, F. J.; McCully, C.; Nugent, P. E.; Sollerman, J.; Taddia, F.; Kulkarni, S. R.
2018-01-01
Early observations of Type Ia supernovae (SNe Ia) provide a unique probe of their progenitor systems and explosion physics. Here we report the intermediate Palomar Transient Factory (iPTF) discovery of an extraordinarily young SN Ia, iPTF 16abc. By fitting a power law to our early light curve, we infer that first light for the SN, that is, when the SN could have first been detected by our survey, occurred only 0.15{+/- }0.070.15 days before our first detection. In the ∼24 hr after discovery, iPTF 16abc rose by ∼2 mag, featuring a near-linear rise in flux for ≳ 3 days. Early spectra show strong C II absorption, which disappears after ∼7 days. Unlike the extensively observed Type Ia SN 2011fe, the {(B-V)}0 colors of iPTF 16abc are blue and nearly constant in the days after explosion. We show that our early observations of iPTF 16abc cannot be explained by either SN shock breakout and the associated, subsequent cooling or the SN ejecta colliding with a stellar companion. Instead, we argue that the early characteristics of iPTF 16abc, including (i) the rapid, near-linear rise, (ii) the nonevolving blue colors, and (iii) the strong C II absorption, are the result of either ejecta interaction with nearby, unbound material or vigorous mixing of radioactive 56Ni in the SN ejecta, or a combination of the two. In the next few years, dozens of very young normal SNe Ia will be discovered, and observations similar to those presented here will constrain the white dwarf explosion mechanism.
Terletska, Kateryna; Maderich, Vladimir; Brovchenko, Igor; Jung, Kyung Tae
2013-04-01
In the freshwater lakes in moderate latitudes stratification occurs as a result of the seasonal warming of the surface water layer. Than the intense wind surges (usually in autumn) tilt the surface and generate long basin-scale low-frequency standing internal waves (seiches). Depending on the initial interface tilt and stratification wide spectra of possible flow regimes can be observed [1]-[2].They varied from small amplitude symmetric seiches to large amplitude nonlinear waves.Nonlinearity leads to an asymmetry of internal waves and appearance of the surge or bore and further disintegration of it on a sequence of solitary waves. In present study degeneration of the strongly nonlinear internal seiches in elongated lakes with a concave "spoon-like" topography is investigated.Two different three-dimensional non-hydrostatic free-surface numerical models are used to investigate degeneration of large internal waves and its subsequent interaction with the concave lake slope. One of this model is non-hydrostatic model [3] and the other is a well-known MIT model. At first we consider idealized elongated elliptic-shape lake with the dimension of 5 km X 1 km with the maximal depth 30 m. The stratification in lake is assumed to be given in a form of the tangent function with a density difference between upper and lower layers 2 kgm-3 . It is assumed that motion in such lake is initiated by inclination of thermocline on a certain angle. Than lake adjusts to return to its original state producing internal seiches which begin interacting with a bottom topography. The process of degeneration of internal seiches in the lake with concave ends consist of chain of elementary processes: 1) steeping of long basin scale large amplitude wave, that evolve into internal surge, 2) surge interact with concave lake ends that leads the concentration of the flow and formation of down slope bottom jet along the lake axis, 3) due to cumulative effect local velocity in the jet accelerates up to
Zhao, Yun; Law, Henry C H; Zhang, Zaijun; Lam, Herman C; Quan, Quan; Li, Guohui; Chu, Ivan K
2015-10-09
In this study we developed a fully automated three-dimensional (3D) liquid chromatography methodology-comprising hydrophilic interaction separation as the first dimension, strong cation exchange fractionation as the second dimension, and low-pH reversed-phase (RP) separation as the third dimension-in conjunction downstream with additional complementary porous graphitic carbon separation, to capture non-retained hydrophilic analytes, for both shotgun proteomics and N-glycomics analyses. The performance of the 3D system alone was benchmarked through the analysis of the total lysate of Saccharomyces cerevisiae, leading to improved hydrophilic peptide coverage, from which we identified 19% and 24% more proteins and peptides, respectively, relative to those identified from a two-dimensional hydrophilic interaction liquid chromatography and low-pH RP chromatography (HILIC-RP) system over the same mass spectrometric acquisition time; consequently, the 3D platform also provided enhanced proteome and protein coverage. When we applied the integrated technology to analyses of the total lysate of primary cerebellar granule neurons, we characterized a total of 2201 proteins and 16,937 unique peptides for this primary cell line, providing one of its most comprehensive datasets. Our new integrated technology also exhibited excellent performance in the first N-glycomics analysis of cynomolgus monkey plasma; we successfully identified 122 proposed N-glycans and 135 N-glycosylation sites from 122 N-glycoproteins, and confirmed the presence of 38 N-glycolylneuraminic acid-containing N-glycans, a rare occurrence in human plasma, through tandem mass spectrometry for the first time. Copyright © 2015 Elsevier B.V. All rights reserved.
Transport Theory for Plasmas that are Strongly Magnetized and Strongly Coupled
Baalrud, Scott; Daligault, Jerome
2016-10-01
Plasmas with components that are magnetized, strongly coupled, or both arise in a variety of frontier plasma physics experiments including magnetized dusty plasmas, nonneutral plasmas, magnetized ICF concepts, as well as from self-generated fields in ICF. Here, a species is considered strongly magnetized if the gyroradius is smaller than the spatial scale over which Coulomb interactions occur. A theory for transport properties is described that treats a wide range of both coupling and magnetization strengths. The approach is based on an extension of the recent effective potential transport theory to include a strong magnetic field. The underlying kinetic theory is based on an extension of the Boltzmann equation to include a strong magnetic field in the dynamics of binary scattering events. Corresponding magnetohydrodynamic equations are derived by solving the kinetic equation using a Chapman-Enskog like spectral method. Results are compared with classical molecular dynamics simulations of self-diffusion of the one component plasmas, and with simulations of parallel to perpendicular temperature equilibration of an initially anisotropic distribution. This material is based upon work supported by AFOSR Award FA9550-16-1-0221 and DOE OFES Award DE-SC0016159.
Pereira, Jorge F B; Barber, Patrick S; Kelley, Steven P; Berton, Paula; Rogers, Robin D
2017-10-11
The properties of double salt ionic liquids based on solutions of cholinium acetate ([Ch][OAc]), ethanolammonium acetate ([NH 3 (CH 2 ) 2 OH][OAc]), hydroxylammonium acetate ([NH 3 OH][OAc]), ethylammonium acetate ([NH 3 CH 2 CH 3 ][OAc]), and tetramethylammonium acetate ([N(CH 3 ) 4 ][OAc]) in 1-ethyl-3-methylimidazolium acetate ([C 2 mim][OAc]) were investigated by NMR spectroscopy and X-ray crystallography. Through mixture preparation, the solubility of [N(CH 3 ) 4 ][OAc] is the lowest, and [Ch][OAc] shows a 3-fold lower solubility than the other hydroxylated ammonium acetate-based salts in [C 2 mim][OAc] at room temperature. NMR and X-ray crystallographic studies of the pure salts suggest that the molecular-level mechanisms governing such miscibility differences are related to the weaker interactions between the -NH 3 groups and [OAc] - , even though three of these salts possess the same strong 1 : 1 hydrogen bonds between the cation -OH group and the [OAc] - ion. The formation of polyionic clusters between the anion and those cations with unsatisfied hydrogen bond donors seems to be a new tool by which the solubility of these salts in [C 2 mim][OAc] can be controlled.
Kakwere, Hamilton
2015-04-03
Herein we prepare nanohybrids by incorporating iron oxide nanocubes (cubic-IONPs) within a thermo-responsive polymer shell that can act as drug carriers for doxorubicin(doxo). The cubic-shaped nanoparticles employed are at the interface between superparamagnetic and ferromagnetic behavior and have an exceptionally high specific absorption rate (SAR) but their functionalization is extremely challenging compared to bare superparamagnetic iron oxide nanoparticles as they strongly interact with each other. By conducting the polymer grafting reaction using reversible addition-fragmentation chain transfer (RAFT) polymerization in a viscous solvent medium, we have here developed a facile approach to decorate the nanocubes with stimuli-responsive polymers. When the thermo-responsive shell is composed of poly(N-isopropyl acrylamide-co-polyethylene glycolmethylether acrylate), nanohybrids have a phase transition temperature, the lower critical solution temperature (LCST), above 37 °C in physiological conditions. Doxo loaded nanohybrids exhibited a negligible drug release below 37 °C but showed a consistent release of their cargo on demand by exploiting the capability of the nanocubes to generate heat under an alternating magnetic field (AMF). Moreover, the drug free nanocarrier does not exhibit cytotoxicity even when administered at high concentration of nanocubes (1g/L of iron) and internalized at high extent (260 pg of iron per cell). We have also implemented the synthesis protocol to decorate the surface of nanocubes with poly(vinylpyridine) polymer and thus prepare pH-responsive shell coated nanocubes.
Strongly Correlated Topological Insulators
2016-02-03
Strongly Correlated Topological Insulators In the past year, the grant was used for work in the field of topological phases, with emphasis on finding...surface of topological insulators. In the past 3 years, we have started a new direction, that of fractional topological insulators. These are materials...in which a topologically nontrivial quasi-flat band is fractionally filled and then subject to strong interactions. The views, opinions and/or
Tolkovsky, A M; Braun, S; Levitzki, A
1982-01-01
The kinetics of turkey erythrocyte membrane adenylate cyclase activation by beta-agonists and guanyl-5'-yl imidodiphosphate is explored as a function of the concentration of the GTP regulatory protein and of the catalytic unit. It was found that the overall kinetics of activation is first order and is independent of the concentration of the GTP regulatory unit N, the catalytic unit C, and of hormone over a very wide concentration range. It was established that the rate-limiting step does not involve GDP dissociation from the inactive N unit or the association between activated N' and C. Also, it was found that guanyl-5'-yl imidodiphosphate binding occurs in a random fashion and is not hormone dependent. These results enable us to exclude models of the sequential type in which N in its inactive form is bound to receptor R, is released in an active form N' upon hormone activation, and then binds to C, activating the latter. An acceptable model that accounts for all of the data conforms to the original formulation of "collision coupling" in which N is tightly associated to C at all times.
Bryan, Louise C; Weilandt, Daniel R; Bachmann, Andreas L; Kilic, Sinan; Lechner, Carolin C; Odermatt, Pascal D; Fantner, Georg E; Georgeon, Sandrine; Hantschel, Oliver; Hatzimanikatis, Vassily; Fierz, Beat
2017-10-13
Chromatin recruitment of effector proteins involved in gene regulation depends on multivalent interaction with histone post-translational modifications (PTMs) and structural features of the chromatin fiber. Due to the complex interactions involved, it is currently not understood how effectors dynamically sample the chromatin landscape. Here, we dissect the dynamic chromatin interactions of a family of multivalent effectors, heterochromatin protein 1 (HP1) proteins, using single-molecule fluorescence imaging and computational modeling. We show that the three human HP1 isoforms are recruited and retained on chromatin by a dynamic exchange between histone PTM and DNA bound states. These interactions depend on local chromatin structure, the HP1 isoforms as well as on PTMs on HP1 itself. Of the HP1 isoforms, HP1α exhibits the longest residence times and fastest binding rates due to DNA interactions in addition to PTM binding. HP1α phosphorylation further increases chromatin retention through strengthening of multivalency while reducing DNA binding. As DNA binding in combination with specific PTM recognition is found in many chromatin effectors, we propose a general dynamic capture mechanism for effector recruitment. Multiple weak protein and DNA interactions result in a multivalent interaction network that targets effectors to a specific chromatin modification state, where their activity is required. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.
International Nuclear Information System (INIS)
Gencheva, R.; Stefanova, A.; Groudev, P.
2013-01-01
Highlights: • We model an ex-vessel MCCI severe accident with ASTECv2/MEDICIS computer code. • Represented NPP is VVER1000 nuclear power plant. • MCCI analyses concern different H 2 O and CO 2 contents in the reactor pit concrete. • Analyses demonstrate significant influence of H 2 O and CO 2 on the ablation kinetics. • Analyses demonstrate significant influence of H 2 O and CO 2 on the melt-through time. - Abstract: This investigation was done in the frame of SARNET2 European Network of Excellence on Severe Accidents project (6-th Framework Program of the European Commission), joint program activity JPA-2, WP6-4. ASTECv2/MEDICIS computer code was used to simulate the ex-vessel corium–concrete interaction cases. This code, jointly developed by the IRSN (France) and GRS (Germany) for simulation of severe accidents, is now considered as the European reference simulation tool. As a reference nuclear power plant for these ASTECv2/MEDICIS calculations the VVER1000 reactor type was used. The main goal of this paper is to investigate the influence of water content (H 2 O) and the content of carbon dioxide (CO 2 ) in the concrete on the kinetics of molten corium–concrete interaction (MCCI) between the molten corium and reactor basemat concrete. In this paper, there are investigated different concentrations of H 2 O and CO 2 in the concrete interacting with the corium poured after reactor vessel failure during a severe accident in VVER1000 nuclear power plant
International Nuclear Information System (INIS)
Raković, Milun J
2011-01-01
The standard quantum mechanical description of the motion of a charged particle in the field of a stationary magnetic monopole is notorious for the presence of unnatural singularities in the Hamiltonian operator originating in the vector potential A(r) used to describe the magnetic field of the monopole. In this paper, an elementary quantum mechanical formulation of the problem which involves only the physically observable field B(r) is presented. This is achieved by treating as a fundamental observable of the charged particle its kinetic momentum instead of the linear momentum p. An irreducible representation of the fundamental commutation relations involving the operators r-hat. It is shown that the existence of an irreducible representation requires that Dirac’s charge quantization condition is satisfied. Also, it is demonstrated that, from the quantum mechanical perspective, the singularities (appearing when the vector potential is introduced) are in fact properties of coordinate representations of the fundamental commutation relations. (paper)
Shiraiwa, M.; Pfrang, C.; Koop, T.; Pöschl, U.
2012-03-01
We present a novel kinetic multi-layer model for gas-particle interactions in aerosols and clouds (KM-GAP) that treats explicitly all steps of mass transport and chemical reaction of semi-volatile species partitioning between gas phase, particle surface and particle bulk. KM-GAP is based on the PRA model framework (Pöschl-Rudich-Ammann, 2007), and it includes gas phase diffusion, reversible adsorption, surface reactions, bulk diffusion and reaction, as well as condensation, evaporation and heat transfer. The size change of atmospheric particles and the temporal evolution and spatial profile of the concentration of individual chemical species can be modeled along with gas uptake and accommodation coefficients. Depending on the complexity of the investigated system and the computational constraints, unlimited numbers of semi-volatile species, chemical reactions, and physical processes can be treated, and the model shall help to bridge gaps in the understanding and quantification of multiphase chemistry and microphysics in atmospheric aerosols and clouds. In this study we demonstrate how KM-GAP can be used to analyze, interpret and design experimental investigations of changes in particle size and chemical composition in response to condensation, evaporation, and chemical reaction. For the condensational growth of water droplets, our kinetic model results provide a direct link between laboratory observations and molecular dynamic simulations, confirming that the accommodation coefficient of water at ~270 K is close to unity (Winkler et al., 2006). Literature data on the evaporation of dioctyl phthalate as a function of particle size and time can be reproduced, and the model results suggest that changes in the experimental conditions like aerosol particle concentration and chamber geometry may influence the evaporation kinetics and can be optimized for efficient probing of specific physical effects and parameters. With regard to oxidative aging of organic aerosol
T. Koop; U. Pöschl; S. T. Martin; S. Vlasenko; E. Mikhailov
2009-01-01
Interactions with water are crucial for the properties, transformation and climate effects of atmospheric aerosols. Here we outline characteristic features and differences in the interaction of amorphous and crystalline aerosol particles with water vapor. Using a hygroscopicity tandem differential mobility analyzer (H-TDMA), we performed hydration, dehydration and cyclic hydration&dehydration experiments with aerosol particles composed of levoglucosan, oxalic acid and ammonium sulfate (diamet...
Wang, Caifen; Wang, Xiaobo; Xu, Xiaonan; Liu, Botao; Xu, Xu; Sun, Lixin; Li, Haiyan; Zhang, Jiwen
2016-02-25
The individual determination of the apparent dissociation rate constant (kd,app) using high performance affinity chromatography (HPAC) is a tedious process requiring numerous separate tests and massive data fitting, unable to provide the apparent association rate constant (ka) and equilibrium binding constant (Ka). In this study, a HPAC with mass spectrometry detection (HPAC-MS/MS) was employed to determine the drug-cyclodextrin (CD) interaction kinetics with low sample loading quantity (drugs determined in one injection. The kd,app measured by HPAC-MS/MS approach were 0.89 ± 0.07, 4.34 ± 0.01, 1.48 ± 0.01 and 7.77 ± 0.04 s(-1) for ketoprofen, trimethoprim, indapamide and acetaminophen, with kd,app for acetaminophen consistent with that from the HPAC method with UV detector in our previous studies. For twenty drugs with diverse structures and chemical properties, good correlationship was found between kd,app measured by single compound analysis method and high-throughput HPAC-MS/MS approach, with the correlation coefficient of 0.987 and the significance F less than 0.001. Comprehensive quantification of ka,app, kd,app and Ka values was further performed based on the measurement of kd,app by peak profiling method and Ka by the peak fitting method. And the investigation of the drug-CD interaction kinetics under different conditions indicated that the column temperature and mobile phase composition significantly affected the determination of ka,app, kd,app and Ka while also dependent on the acidity and basicity of drugs. In summary, the high-throughput HPAC-MS/MS approach has been demonstrated high efficiency in determination of the drug-CD primary interaction kinetic parameter, especially, kd,app, being proven as a novel tool in screening the right CD for the solubilization of the right drug. Copyright © 2016 Elsevier B.V. All rights reserved.
Kinetic modelling of enzymatic starch hydrolysis
Bednarska, K.A.
2015-01-01
<strong>Kinetic modelling of enzymatic starch hydrolysis – a summarystrong>
K.A. Bednarska
The dissertation entitled ‘Kinetic modelling of enzymatic starch hydrolysis’ describes the enzymatic hydrolysis and kinetic modelling of liquefaction and saccharification of wheat starch.
Energy Technology Data Exchange (ETDEWEB)
Avila, Ivonete; Silva, Eugenio A.G.; Mortari, Daniela A.; Crnkovic, Paula M.; Milioli, Fernando E. [University of Sao Paulo (EESC/USP), Sao Carlos, SP (Brazil). Engineering School. Group of Thermal and Fluids Engineering], Emails: iavila@sc.usp.br, eugenio.silva@usp.br, paulam@sc.usp.br, milioli@sc.usp.br
2010-07-01
This paper evaluates the behavior of kinetic energy for different heating rates ({alpha}) and particle sizes of the material in the study of the coal combustion process. It aims to obtain a response surface in a large range of particle size, using heating rates between the minimum and maximum values allowed by the equipment. Therefore it searches for a model to evaluate the interaction effect between particle size and the heating rate and to predict the activation energy of the process studied. The activation energy of the process was determined using the isoconversional model Model Free Kinetics. In this model, the activation energy (E{sub {alpha}}) is obtained as a function of the reaction extent ({alpha}). The subscript in E{sub {alpha}} designates the values related to a given value of conversion ({alpha}). All experiments were conducted in thermogravimetric balance using samples of a Brazilian coal (EC4500) witch average particle size between 163 to 650 {mu}m and heating rates between 10 and 40 deg C min{sup -1} in dynamic atmosphere of air. A central rotatable composite design was applied for the 2{sup 2} factorial design including 4 tests under the axial conditions and 3 repetitions in the central point. As expected, the results show that both the particle size and the heating rate affected significantly the values of activation energy of the coal combustion process obtained by the model used. (author)
International Nuclear Information System (INIS)
Keskin, Mustafa; Canko, Osman; Deviren, Bayram
2007-01-01
We analyze, within a mean-field approach, the stationary states of the kinetic spin-32 Blume-Capel (BC) model by the Glauber-type stochastic dynamics and subject to a time-dependent oscillating external magnetic field. The dynamic phase transition (DPT) points are obtained by investigating the behavior of the dynamic magnetization as a function of temperature and as well as calculating the Liapunov exponent. Phase diagrams are constructed in the temperature and crystal-field interaction plane. We find five fundamental types of phase diagrams for the different values of the reduced magnetic field amplitude parameter (h) in which they present a disordered, two ordered phases and the coexistences phase regions. The phase diagrams also exhibit a dynamic double-critical end point for 0 5.06
International Nuclear Information System (INIS)
Keskin, M.; Canko, O.; Temizer, U.
2007-01-01
Within a mean-field approach, the stationary states of the kinetic spin-1 Blume-Capel model in the presence of a time-dependent oscillating external magnetic field is studied. The Glauber-type stochastic dynamics is used to describe the time evolution of the system and obtain the mean-field dynamic equation of motion. The dynamic phase-transition points are calculated and phase diagrams are presented in the temperature and crystal-field interaction plane. According to the values of the magnetic field amplitude, three fundamental types of phase diagrams are found: One exhibits a dynamic tricritical point, while the other two exhibit a dynamic zero-temperature critical point
Energy Technology Data Exchange (ETDEWEB)
Keskin, Mustafa [Department of Physics, Erciyes University, 38039 Kayseri (Turkey)]. E-mail: keskin@erciyes.edu.tr; Canko, Osman [Department of Physics, Erciyes University, 38039 Kayseri (Turkey); Deviren, Bayram [Department of Physics, Erciyes University, 38039 Kayseri (Turkey)
2007-06-15
We analyze, within a mean-field approach, the stationary states of the kinetic spin-32 Blume-Capel (BC) model by the Glauber-type stochastic dynamics and subject to a time-dependent oscillating external magnetic field. The dynamic phase transition (DPT) points are obtained by investigating the behavior of the dynamic magnetization as a function of temperature and as well as calculating the Liapunov exponent. Phase diagrams are constructed in the temperature and crystal-field interaction plane. We find five fundamental types of phase diagrams for the different values of the reduced magnetic field amplitude parameter (h) in which they present a disordered, two ordered phases and the coexistences phase regions. The phase diagrams also exhibit a dynamic double-critical end point for 0
Energy Technology Data Exchange (ETDEWEB)
Yourshaw, Ivan [Univ. of California, Berkeley, CA (United States)
1998-07-09
The diatomic halogen atom-rare gas diatomic complexes KrBr^{-}, XeBr^{-}, and KrCl^{-} are studied in this work by zero electron kinetic energy (ZEKE) spectroscopy in order to characterize the weak intermolecular diatomic potentials of these species. Also, the ZEKE and threshold photodetachment spectra of the polyatomic clusters Ar_{n}Br^{-} (n = 2-9) and Ar_{n}I^{-} (n = 2-19) are studied to obtain information about the non-additive effects on the interactions among the atoms. This work is part of an ongoing effort to characterize the pair and many-body potentials of the complete series of rare gas halide clusters. In these studies we obtain information about both the anionic and neutral clusters.
DEFF Research Database (Denmark)
van Leeuwen, Theo; Djonov, Emilia
2014-01-01
After discussing broad cultural drivers behind the development of kinetic typography, the chapter outlines an approach to analysing kinetic typography which is based on Halliday's theory of transitivity, as applied by Kress and Van Leeuwen to visual images....
DEFF Research Database (Denmark)
van Leeuwen, Theo; Djonov, Emilia
2014-01-01
After discussing broad cultural drivers behind the development of kinetic typography, the chapter outlines an approach to analysing kinetic typography which is based on Halliday's theory of transitivity, as applied by Kress and Van Leeuwen to visual images.......After discussing broad cultural drivers behind the development of kinetic typography, the chapter outlines an approach to analysing kinetic typography which is based on Halliday's theory of transitivity, as applied by Kress and Van Leeuwen to visual images....
Lokhande, R. S.; Singare, P. U.; Prabhavalkar, T. S.
2008-09-01
In the present investigation, the 82Br radioactive isotope was used as a tracer to study the kinetics and mechanism of the exchange reaction between an ion exchange resin and an external solution of bromide ions. In an attempt to study the reversible bromide isotope exchange reaction kinetics, it was expected that whether the initial step was the exchange of radioactive bromide ions from the solution to the ion exchange resin (forward reaction) or from the ion exchange resin to the solution (reverse reaction), the two ion-isotope exchange reactions should occur simultaneously, which was further confirmed by the experimental values of specific reaction rates, 0.142 and 0.141 min-1, respectively. The results will be useful to standardize the process parameters so as to achieve optimum use of ion exchange resins in various industrial applications.
Litvinov, Rustem I.; Mekler, Andrey; Shuman, Henry; Bennett, Joel S.; Barsegov, Valeri; Weisel, John W.
2012-01-01
Using a combined experimental and theoretical approach named binding-unbinding correlation spectroscopy (BUCS), we describe the two-dimensional kinetics of interactions between fibrinogen and the integrin αIIbβ3, the ligand-receptor pair essential for platelet function during hemostasis and thrombosis. The methodology uses the optical trap to probe force-free association of individual surface-attached fibrinogen and αIIbβ3 molecules and forced dissociation of an αIIbβ3-fibrinogen complex. This novel approach combines force clamp measurements of bond lifetimes with the binding mode to quantify the dependence of the binding probability on the interaction time. We found that fibrinogen-reactive αIIbβ3 pre-exists in at least two states that differ in their zero force on-rates (kon1 = 1.4 × 10−4 and kon2 = 2.3 × 10−4 μm2/s), off-rates (koff1 = 2.42 and koff2 = 0.60 s−1), and dissociation constants (Kd1 = 1.7 × 104 and Kd2 = 2.6 × 103 μm−2). The integrin activator Mn2+ changed the on-rates and affinities (Kd1 = 5 × 104 and Kd2 = 0.3 × 103 μm−2) but did not affect the off-rates. The strength of αIIbβ3-fibrinogen interactions was time-dependent due to a progressive increase in the fraction of the high affinity state of the αIIbβ3-fibrinogen complex characterized by a faster on-rate. Upon Mn2+-induced integrin activation, the force-dependent off-rates decrease while the complex undergoes a conformational transition from a lower to higher affinity state. The results obtained provide quantitative estimates of the two-dimensional kinetic rates for the low and high affinity αIIbβ3 and fibrinogen interactions at the single molecule level and offer direct evidence for the time- and force-dependent changes in αIIbβ3 conformation and ligand binding activity, underlying the dynamics of fibrinogen-mediated platelet adhesion and aggregation. PMID:22893701
Energy Technology Data Exchange (ETDEWEB)
Calamini, Barbara; Santarsiero, Bernard D.; Boutin, Jean A.; Mesecar, Andrew D. (IdRS); (UIC)
2008-09-12
Melatonin exerts its biological effects through at least two transmembrane G-protein-coupled receptors, MT1 and MT2, and a lower-affinity cytosolic binding site, designated MT3. MT3 has recently been identified as QR2 (quinone reductase 2) (EC 1.10.99.2) which is of significance since it links the antioxidant effects of melatonin to a mechanism of action. Initially, QR2 was believed to function analogously to QR1 in protecting cells from highly reactive quinones. However, recent studies indicate that QR2 may actually transform certain quinone substrates into more highly reactive compounds capable of causing cellular damage. Therefore it is hypothesized that inhibition of QR2 in certain cases may lead to protection of cells against these highly reactive species. Since melatonin is known to inhibit QR2 activity, but its binding site and mode of inhibition are not known, we determined the mechanism of inhibition of QR2 by melatonin and a series of melatonin and 5-hydroxytryptamine (serotonin) analogues, and we determined the X-ray structures of melatonin and 2-iodomelatonin in complex with QR2 to between 1.5 and 1.8 {angstrom} (1 {angstrom} = 0.1 nm) resolution. Finally, the thermodynamic binding constants for melatonin and 2-iodomelatonin were determined by ITC (isothermal titration calorimetry). The kinetic results indicate that melatonin is a competitive inhibitor against N-methyldihydronicotinamide (K{sub i} = 7.2 {mu}M) and uncompetitive against menadione (K{sub i} = 92 {mu}M), and the X-ray structures shows that melatonin binds in multiple orientations within the active sites of the QR2 dimer as opposed to an allosteric site. These results provide new insights into the binding mechanisms of melatonin and analogues to QR2.
Calamini, Barbara; Santarsiero, Bernard D; Boutin, Jean A; Mesecar, Andrew D
2008-07-01
Melatonin exerts its biological effects through at least two transmembrane G-protein-coupled receptors, MT1 and MT2, and a lower-affinity cytosolic binding site, designated MT3. MT3 has recently been identified as QR2 (quinone reductase 2) (EC 1.10.99.2) which is of significance since it links the antioxidant effects of melatonin to a mechanism of action. Initially, QR2 was believed to function analogously to QR1 in protecting cells from highly reactive quinones. However, recent studies indicate that QR2 may actually transform certain quinone substrates into more highly reactive compounds capable of causing cellular damage. Therefore it is hypothesized that inhibition of QR2 in certain cases may lead to protection of cells against these highly reactive species. Since melatonin is known to inhibit QR2 activity, but its binding site and mode of inhibition are not known, we determined the mechanism of inhibition of QR2 by melatonin and a series of melatonin and 5-hydroxytryptamine (serotonin) analogues, and we determined the X-ray structures of melatonin and 2-iodomelatonin in complex with QR2 to between 1.5 and 1.8 A (1 A=0.1 nm) resolution. Finally, the thermodynamic binding constants for melatonin and 2-iodomelatonin were determined by ITC (isothermal titration calorimetry). The kinetic results indicate that melatonin is a competitive inhibitor against N-methyldihydronicotinamide (K(i)=7.2 microM) and uncompetitive against menadione (K(i)=92 microM), and the X-ray structures shows that melatonin binds in multiple orientations within the active sites of the QR2 dimer as opposed to an allosteric site. These results provide new insights into the binding mechanisms of melatonin and analogues to QR2.
Loveridge, E Joel; Allemann, Rudolf K
2010-06-29
Dihydrofolate reductase from the hyperthermophile Thermotoga maritima (TmDHFR) is unique among structurally characterized chromosomal DHFRs in that it forms a stable homodimer. Dimerization is believed to play a key role in the high thermal stability of TmDHFR, which is reflected in a melting temperature in excess of 85 degrees C. The dimer interface of TmDHFR is composed of a hydrophobic core with charged residues around the periphery. In particular, Lys129 of each subunit forms three-membered salt bridges with Glu136 and Glu138 of the other subunit. To probe the role of these salt bridges in the dimerization and thermal stability of TmDHFR, we generated a series of variants (TmDHFR-K129E, TmDHFR-E136K, TmDHFR-E138K, and TmDHFR-E136K/E138K) in which these residues were exchanged for residues whose side chains bear the opposite charge. Our results indicate that these salt bridges are key for the high thermal stability of TmDHFR but are not a requirement for dimerization. Although the rate of dihydrofolate reduction by TmDHFR is not significantly affected by the loss of the K129-E136-E138 salt bridges, changes to the temperature dependence of the kinetic isotope effect on hydride transfer are observed. These changes are in agreement with the proposal that DHFR catalysis may be affected by changes to the conformational ensemble of the enzyme rather than only to the coupling of protein motions to the reaction coordinate.
Strong Electroweak Symmetry Breaking
Grinstein, Benjamin
2011-01-01
Models of spontaneous breaking of electroweak symmetry by a strong interaction do not have fine tuning/hierarchy problem. They are conceptually elegant and use the only mechanism of spontaneous breaking of a gauge symmetry that is known to occur in nature. The simplest model, minimal technicolor with extended technicolor interactions, is appealing because one can calculate by scaling up from QCD. But it is ruled out on many counts: inappropriately low quark and lepton masses (or excessive FCNC), bad electroweak data fits, light scalar and vector states, etc. However, nature may not choose the minimal model and then we are stuck: except possibly through lattice simulations, we are unable to compute and test the models. In the LHC era it therefore makes sense to abandon specific models (of strong EW breaking) and concentrate on generic features that may indicate discovery. The Technicolor Straw Man is not a model but a parametrized search strategy inspired by a remarkable generic feature of walking technicolor,...
A group-kinetic theory of turbulent collective collisions
International Nuclear Information System (INIS)
Tchen, C.M.; Misguich, J.H.
1983-05-01
The main objective is the derivation of the kinetic equation of turbulence which has a memory in the turbulent collision integral. We consider the basic pair-interaction, and the interaction between a fluctuation and the organized cluster of other fluctuations in the collection systems, called the multiple interaction. By a group-scaling procedure, a fluctuation is decomposed into three groups to represent the three coupled transport processes of evolution, transport coefficient, and relaxation. The kinetic equation of the scaled singlet distribution is capable of investigating the spectrum of turbulence without the need of the knowledge of the pair distribution. The exact propagator describes the detailed trajectory in the phase space, and is fundamental to the Lagrangian-Eulerian transformation. We calculate the propagator and its scaled groups by means of a probability of retrograde transition. Thus our derivation of the kinetic equation of the distribution involves a parallel development of the kinetic equations of the propagator and the transition probability. In this way, we can avoid the assumptions of independence and normality. Our result shows that the multiple interaction contributes to a shielding and an enchancement of the collision in weak turbulence and strong turbulence, respectively. The weak turbulence is dominated by the wave resonance, and the strong turbulence is dominated by the diffusion
Xie, Fan; Wang, Shaoyun; Zhang, Li; Wu, Jinhong; Wang, Zhengwu
2018-03-01
We synthesised a novel sericin peptide (SP-GI) with α-d-glucosidase inhibitory activity, which has a sequence of SEDSSEVDIDLGN. The kinetics of its peptide-induced inhibition on α-d-glucosidase activity and its interaction mechanism merging with molecular docking were both investigated. SP-GI exhibited significant inhibitory activity with an IC 50 of 2.9 ± 0.1 µmol L -1 and this inhibition was reversible and non-competitive with a K i value of 1.0 ± 0.1 µmol L -1 . An interaction study with SP-GI revealed it bound to α-d-glucosidase at a single binding site, resulting in alterations in α-d-glucosidase secondary structure. This led to quenching of intrinsic α-d-glucosidase fluorescence by a static quenching mechanism. Molecular docking results showed that the SP-GI binding site on α-d-glucosidase differed from acarbose, with hydrogen bonding and van der Waals forces being the main binding drivers. These findings suggest the potential use for SP-GI or other natural sericin peptides as dietary supplements for the treatment of type 2 diabetes. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.
Directory of Open Access Journals (Sweden)
M. Ammann
2007-12-01
Full Text Available A kinetic model framework with consistent and unambiguous terminology and universally applicable rate equations and parameters for aerosol and cloud surface chemistry and gas-particle interactions has been presented in the preceding companion paper by Pöschl, Rudich and Ammann (Pöschl et al., 2007, abbreviated PRA. It allows to describe mass transport and chemical reaction at the gas-particle interface and to link aerosol and cloud surface processes with gas phase and particle bulk processes. Here we present multiple exemplary model systems and calculations illustrating how the general mass balance and rate equations of the PRA framework can be easily reduced to compact sets of equations which enable a mechanistic description of time and concentration dependencies of trace gas uptake and particle composition in systems with one or more chemical components and physicochemical processes. Time-dependent model scenarios show the effects of reversible adsorption, surface-bulk transport, and chemical aging on the temporal evolution of trace gas uptake by solid particles and solubility saturation of liquid particles. They demonstrate how the transformation of particles and the variation of trace gas accommodation and uptake coefficients by orders of magnitude over time scales of microseconds to days can be explained and predicted from the initial composition and basic kinetic parameters of model systems by iterative calculations using standard spreadsheet programs. Moreover, they show how apparently inconsistent experimental data sets obtained with different techniques and on different time scales can be efficiently linked and mechanistically explained by application of consistent model formalisms and terminologies within the PRA framework. Steady-state model scenarios illustrate characteristic effects of gas phase composition and basic kinetic parameters on the rates of mass transport and chemical reactions. They demonstrate how adsorption and
Directory of Open Access Journals (Sweden)
M. Shiraiwa
2012-03-01
Full Text Available We present a novel kinetic multi-layer model for gas-particle interactions in aerosols and clouds (KM-GAP that treats explicitly all steps of mass transport and chemical reaction of semi-volatile species partitioning between gas phase, particle surface and particle bulk. KM-GAP is based on the PRA model framework (Pöschl-Rudich-Ammann, 2007, and it includes gas phase diffusion, reversible adsorption, surface reactions, bulk diffusion and reaction, as well as condensation, evaporation and heat transfer. The size change of atmospheric particles and the temporal evolution and spatial profile of the concentration of individual chemical species can be modeled along with gas uptake and accommodation coefficients. Depending on the complexity of the investigated system and the computational constraints, unlimited numbers of semi-volatile species, chemical reactions, and physical processes can be treated, and the model shall help to bridge gaps in the understanding and quantification of multiphase chemistry and microphysics in atmospheric aerosols and clouds.
In this study we demonstrate how KM-GAP can be used to analyze, interpret and design experimental investigations of changes in particle size and chemical composition in response to condensation, evaporation, and chemical reaction. For the condensational growth of water droplets, our kinetic model results provide a direct link between laboratory observations and molecular dynamic simulations, confirming that the accommodation coefficient of water at ~270 K is close to unity (Winkler et al., 2006. Literature data on the evaporation of dioctyl phthalate as a function of particle size and time can be reproduced, and the model results suggest that changes in the experimental conditions like aerosol particle concentration and chamber geometry may influence the evaporation kinetics and can be optimized for efficient probing of specific physical effects and parameters. With regard to oxidative
Directory of Open Access Journals (Sweden)
P. Bochsler
2010-02-01
Full Text Available STEREO/PLASTIC determines three-dimensional distributions of solar wind iron ions with unprecedented time resolution. Typically 300 to 1000 counts are registered within each 5 min time interval. For the present study we use the information contained in these distributions to characterize CIRs (Corotating Interaction Regions in two test cases. We perform a consistency test for both the derived physical parameters and for the analytical model of CIRs of Lee (2000. At 1 AU we find that apart from compositional changes the most indicative parameter for marking the time when a CIR passes a spacecraft is the angular deflection of the flow vector of particles. Changes in particle densities and the changes in magnitudes of speeds are apparently less reliable indicators of stream interfaces.
Xie, Fan; Gong, Shengxiang; Zhang, Wei; Wu, Jinhong; Wang, Zhengwu
2017-02-01
In this study, we extracted lignin from Canna edulis ker residue. Its chemical structure, inhibitory activity on α-d-glucosidase, and kinetics as well as interaction mechanism were investigated by using spectrum analysis and docking simulation. The isolated lignin was composed by guaiacyl and syringal units, and exhibited stronger inhibition on α-d-glucosidase than acarbose with the half maximal inhibitory concentration at 5.3±0.3μM. It was a non-competitive inhibitior with K m and K i values of 0.53±0.02mM and 0.92±0.12μM, respectively. It could quench the intrinsic fluorescence of α-d-glucosidase through a static quenching mode. The calculated values of enthalpy and entropy change were 20.8±2.5kJmol -1 and 172.7±0.8Jmol -1 K -1 , respectively. There was a single binding site on α-d-glucosidase for lignin, and the binding distance was 3.2nm. The molecular docking analysis exhibited that the hydrogen bonds, hydropholic interaction, and van der Waals forces were the main forces for lignin bind to α-d-glucosidase. This work provides a new insight into the interaction between the lignin and α-d-glucosidase, which might be beneficial to type 2 diabetes with the application of lignin in functional food and pharmacy fields. Copyright © 2016 Elsevier B.V. All rights reserved.
Directory of Open Access Journals (Sweden)
E. Marsch
1998-01-01
Full Text Available Based on quasilinear theory, a closure scheme for anisotropic multi-component fluid equations is developed for the wave-particle interactions of ions with electromagnetic Alfvén and ion-cyclotron waves propagating along the mean magnetic field. Acceleration and heating rates are calculated. They may be used in the multi-fluid momentum and energy equations as anomalous transport terms. The corresponding evolution equation for the average wave spectrum is established, and the effective growth/damping rate for the spectrum is calculated. Given a simple power-law spectrum, an anomalous collision frequency can be derived which depends on the slope and average intensity of the spectrum, and on the gyrofrequency and the differential motion (with respect to the wave frame of the actual ion species considered. The wave-particle interaction terms attain simple forms resembling the ones for collisional friction and temperature anisotropy relaxation (due to pitch angle scattering with collision rates that are proportional to the gyrofrequency but diminished substantially by the relative wave energy or the fluctuation level with respect the background field. In addition, a set of quasilinear diffusion equations is derived for the reduced (with respect to the perpendicular velocity component velocity distribution functions (VDFs, as they occur in the wave dispersion equation and the related dielectric function for parallel propagation. These reduced VDFs allow one to describe adequately the most prominent observed features, such as an ion beam and temperature anisotropy, in association with the resonant interactions of the particles with the waves on a kinetic level, yet have the advantage of being only dependent upon the parallel velocity component.
From particle to kinetic and hydrodynamic descriptions of flocking
Ha, Seung-Yeal; Tadmor, Eitan
2008-01-01
We discuss the Cucker-Smale's (C-S) particle model for flocking, deriving precise conditions for flocking to occur when pairwise interactions are sufficiently strong long range. We then derive a Vlasov-type kinetic model for the C-S particle model and prove it exhibits time-asymptotic flocking behavior for arbitrary compactly supported initial data. Finally, we introduce a hydrodynamic description of flocking based on the C-S Vlasov-type kinetic model and prove flocking behavior \\emph{without...
Energy Technology Data Exchange (ETDEWEB)
Mangas, Iris; Vilanova, Eugenio; Estevez, Jorge, E-mail: jorge.estevez@umh.es
2011-11-15
Some published studies suggest that low level exposure to organophosphorus esters (OPs) may cause neurological and neurobehavioral effects at long term exposure. These effects cannot be explained by action on known targets. In this work, the interactions (inhibition, spontaneous reactivation and 'ongoing inhibition') of two model OPs (paraoxon, non neuropathy-inducer, and mipafox, neuropathy-inducer) with the chicken brain soluble esterases were evaluated. The best-fitting kinetic model with both inhibitors was compatible with three enzymatic components. The amplitudes (proportions) of the components detected with mipafox were similar to those obtained with paraoxon. These observations confirm the consistency of the results and the model applied and may be considered an external validation. The most sensitive component (E{alpha}) for paraoxon (11-23% of activity, I{sub 50} (30 min) = 9-11 nM) is also the most sensitive for mipafox (I{sub 50} (30 min) = 4 nM). This component is spontaneously reactivated after inhibition with paraoxon. The second sensitive component to paraoxon (E{beta}, 71-84% of activity; I{sub 50} (30 min) = 1216 nM) is practically resistant to mipafox. The third component (E{gamma}, 5-8% of activity) is paraoxon resistant and has I{sub 50} (30 min) of 3.4 {mu}M with mipafox, similar to NTE (neuropathy target esterase). The role of these esterases remains unknown. Their high sensitivity suggests that they may either play a role in toxicity in low-level long-term exposure of organophosphate compounds or have a protective effect related with the spontaneous reactivation. They will have to be considered in further metabolic and toxicological studies. -- Research Highlights: Black-Right-Pointing-Pointer Paraoxon and mipafox interactions have been evaluated with chicken soluble brain esterases. Black-Right-Pointing-Pointer The paraoxon inhibition was analyzed considering the simultaneous spontaneous reactivation. Black
Joneta Witabora; Jonata Witabora
2014-01-01
Kinetic Sculpture was born from a long process of searching new approach in sculpture. The artists tried to escape from 'static' paradigm and tried to implement movement into their works: a sculpture that is mobile. Movement is always a fascinating phenomenon to eyes. Kinetic sculpture strength lies in its unique character in combining science and art. Kinetic Sculptures are really interesting pieces of art. It succeeds to fascinate human everytime.
Katsyuba, Sergey A.; Vener, Mikhail V.; Zvereva, Elena E.; Brandenburg, J. Gerit
2017-03-01
Two variants of density functional theory computations have been applied to characterization of hydrogen bonds of the 1-(2-hydroxylethyl)-3-methylimidazolium acetate ([C2OHmim][OAc]), i.e. with and without inclusion of dispersion interactions. A comparison of the results demonstrates that London dispersion interactions have very little impact on the energetical, geometrical, infrared spectroscopic and electron density parameters of charge-assisted intermolecular hydrogen bonds functioning both in the crystal of the [C2OHmim][OAc] and in the isolated [C2OHmim]+ [OAc]- ion pairs.
International Nuclear Information System (INIS)
Thews, R.L.
1986-01-01
The research reported includes: low energy quark-hadron dynamics; quark-gluon models for hadronic interactions, decays and structure; mathematical and physical properties of nonlinear sigma models, Yang-Mills theories, and Coulomb gases, which are of interest in both particle physics and condensed matter physics; statistical and dynamical aspects of hadronic multiparticle production. 28 refs
Wang, Y.; Nakatsukasa, K.; Rademaker, L.; Berlijn, T.; Johnston, S.
2016-05-01
Mono- and multilayer FeSe thin films grown on SrTiO3 and BiTiO3 substrates exhibit a greatly enhanced superconductivity over that found in bulk FeSe. A number of proposals have been advanced for the mechanism of this enhancement. One possibility is the introduction of a cross-interface electron-phonon (e-ph) interaction between the FeSe electrons and oxygen phonons in the substrates that is peaked in the forward scattering (small {q}) direction due to the two-dimensional nature of the interface system. Motivated by this, we explore the consequences of such an interaction on the superconducting state and electronic structure of a two-dimensional system using Migdal-Eliashberg (ME) theory. This interaction produces not only deviations from the expectations of conventional phonon-mediated pairing but also replica structures in the spectral function and density of states, as probed by angle-resolved photoemission spectroscopy, scanning tunneling microscopy/spectroscopy, and quasiparticle interference imaging. We also discuss the applicability of ME theory for a situation where the e-ph interaction is peaked at small momentum transfer and in the FeSe/STO system.
Czech Academy of Sciences Publication Activity Database
Johnston, S.; Monney, C.; Bisogni, V.; Zhou, K.J.; Kraus, R.; Behr, G.; Strocov, V.N.; Málek, Jiří; Drechsler, S.L.; Geck, J.; Schmitt, T.; van den Brink, J.
2016-01-01
Roč. 7, Feb (2016), 1-7, č. článku 10653. ISSN 2041-1723 Institutional support: RVO:68378271 Keywords : X-ray scattering * electron-lattice interactions * spin-chain cuprates * renormalization of charge- transfer energy Subject RIV: BE - Theoretical Physics Impact factor: 12.124, year: 2016
A consistent description of kinetics and hydrodynamics of quantum Bose-systems
Directory of Open Access Journals (Sweden)
P.A.Hlushak
2004-01-01
Full Text Available A consistent approach to the description of kinetics and hydrodynamics of many-Boson systems is proposed. The generalized transport equations for strongly and weakly nonequilibrium Bose systems are obtained. Here we use the method of nonequilibrium statistical operator by D.N. Zubarev. New equations for the time distribution function of the quantum Bose system with a separate contribution from both the kinetic and potential energies of particle interactions are obtained. The generalized transport coefficients are determined accounting for the consistent description of kinetic and hydrodynamic processes.
Directory of Open Access Journals (Sweden)
Biplab K. Bera
2013-01-01
Full Text Available The kinetics of the interaction of three glycine-containing dipeptides, namely, glycyl-L-alanine (L1-L′H, glycyl-L-asparagine (L2-L′H, and glycyl-L-tyrosine (L3-L′H with has been studied spectrophotometrically in aqueous medium as a function of the molar concentration of , [dipeptide], pH, and temperature at constant ionic strength. Reactions were studied at pH 4.3, where the substrate complex exists predominantly as the hydroxopentaaqua species and dipeptides as the zwitterion. The reaction has been found to proceed via two parallel paths: both processes are ligand dependent. The rate constant for the processes are and . The activation parameters for both the steps were evaluated using Eyring’s equation. The low and large negative value of as well as and indicate an associative mode of activation for both the aqua ligand substitution processes for both the parallel paths. The product of the reaction has been characterized by IR and ESI-mass spectroscopic analyses.
Solyanikova, Inna P; Borzova, Oksana V; Emelyanova, Elena V
2017-07-01
Benzoate 1,2-dioxygenase (BDO) of Rhodococcus opacus 1CP, which carried out the initial attack on benzoate, was earlier shown to be the enzyme with a narrow substrate specificity. A kinetics of interaction between benzoate 1,2-dioxygenase and substituted benzoates was assessed taking into account the enlarged list of the type of inhibition and using whole cells grown on benzoate. The type of inhibition was determined and the constants of a reaction of BDO with benzoate in the presence of 2-chlorobenzoate (2CBA), 3,5-dichlorobenzoate (3,5DCBA), and 3-methylbenzoate (3MBA) were calculated. For 2CBA and 3MBA, the types of inhibition were classified as biparametrically disсoordinated inhibition and transient inhibition (from activation towards inhibition), respectively. The process of not widely recognized pseudoinhibition of a BDO reaction with benzoate by 3,5DCBA was assessed by the vector method for the representation of enzymatic reactions. Ki value was determined for 2CBA, 3MBA, and 3,5DCBA as 337.5, 870.3, and 14.7 μM, respectively.
Lehman, Sean E; Mudunkotuwa, Imali A; Grassian, Vicki H; Larsen, Sarah C
2016-01-26
Understanding complex chemical changes that take place at nano-bio interfaces is of great concern for being able to sustainably implement nanomaterials in key applications such as drug delivery, imaging, and environmental remediation. Typical in vitro assays use cell viability as a proxy to understanding nanotoxicity but often neglect how the nanomaterial surface can be altered by adsorption of solution-phase components in the medium. Protein coronas form on the nanomaterial surface when incubated in proteinaceous solutions. Herein, we apply a broad array of techniques to characterize and quantify protein corona formation on silica nanoparticle surfaces. The porosity and surface chemistry of the silica nanoparticles have been systematically varied. Using spectroscopic tools such as FTIR and circular dichroism, structural changes and kinetic processes involved in protein adsorption were evaluated. Additionally, by implementing thermogravimetric analysis, quantitative protein adsorption measurements allowed for the direct comparison between samples. Taken together, these measurements enabled the extraction of useful chemical information on protein binding onto nanoparticles in solution. Overall, we demonstrate that small alkylamines can increase protein adsorption and that even large polymeric molecules such as poly(ethylene glycol) (PEG) cannot prevent protein adsorption in these systems. The implications of these results as they relate to further understanding nano-bio interactions are discussed.
Pauwels, Petrus J; Colpaert, Francis C
2000-01-01
Activation of the recombinant human α2C-adrenoceptor (α2C AR) by (−)-adrenaline in CHO-K1 cells transiently co-expressing a chimeric Gαq/i1 protein induced a rapid, transient Ca2+ response with a high-magnitude followed by a low-magnitude phase which continued throughout the recorded time period (15 min). Activation of the α2C AR by various α2 AR agonists revealed the following rank order of high-magnitude Ca2+ response [Emax (%) versus 10 μM (−)-adrenaline]: UK 14304 (102±4)=talipexole (101±3)=(−)-adrenaline (100)=d-medetomidine (98±1)>oxymetazoline (81±4)⋍clonidine (75±5). The methoxy- (RX 821002) and ethoxy-derivatives (RX 811059) of idazoxan and the dexefaroxan analogue atipamezole were fully effective as antagonists of both the high- and the low-magnitude Ca2+ response. However, though acting as full antagonists of the high-magnitude response, the further putative α2 AR antagonists idazoxan (27%), SKF 86466 (29%) and dexefaroxan (59%) reversed the low-magnitude response only partially. In conclusion, kinetic analyses of agonist : antagonist interactions at the α2C AR demonstrate a wide spectrum of partial to complete antagonism of the low-magnitude Ca2+ response for structurally related α2 AR ligands. PMID:11090111
Energy Technology Data Exchange (ETDEWEB)
Rho, H.; Jones, C.N.; Rose, R.B. (NCSU)
2010-12-07
The two disparate functions of DCoH1 (dimerization cofactor of HNF-1)/PCD (pterin-4a-carbinolamine dehydratase) are associated with a change in oligomeric state. DCoH dimers enhance the activity of the diabetes-associated transcription factor HNF-1{alpha} (hepatocyte nuclear factor-1{alpha}), while the PCD activity of DCoH1 homotetramers aids in aromatic amino acid metabolism. These complexes compete for the same interface of the DCoH dimer. Formation of the DCoH1/HNF-1{alpha} complex requires cofolding. The homotetramer of the DCoH1 paralogue, DCoH2, interacts with HNF-1{alpha} through simple mixing. To further investigate regulation of DCoH/HNF-1{alpha} complex formation, we measured the stability of the DCoH1 homotetramer through unfolding studies by intrinsic tryptophan fluorescence. DCoH2 unfolding is reversible. Surprisingly, the DCoH1 homotetramer is resistant to guanidine unfolding but refolds at a much lower guanidine concentration. We show that a point mutation at the DCoH1 tetramer interface, Thr 51 Ser, overcomes the dissociation barrier of the homotetramer and increases the interaction with HNF-1{alpha}. The 1.8 {angstrom} resolution crystal structure of DCoH1 T51S shows the presence of an ordered water molecule at the tetramer interface, as in DCoH2, which may destabilize the homotetramer. The equilibrium unfolding data were fit to a two-state model with no apparent intermediate. Folding intermediates were detectable by size exclusion chromatography. For wild-type DCoH1 the intermediates changed with time, suggesting a kinetic origin for the unfolding barrier of the homotetramer. We propose an unfolding pathway in which the tetramer unfolds slowly, but the dimer folds reversibly. Implications for regulation of DCoH1/HNF-1{alpha} complex formation are discussed.
Guiliano, David B; North, Helen; Panayoitou, Eleni; Campbell, Elaine C; McHugh, Kirsty; Cooke, Fiona G M; Silvestre, Marine; Bowness, Paul; Powis, Simon J; Antoniou, Antony N
2017-03-01
HLA-B27 is associated with the inflammatory spondyloarthritides (SpA), although subtypes HLA-B*27:06 and HLA-B*27:09 are not. These subtypes differ from the HLA-B*27:05 disease-associated allele primarily at residues 114 and 116 of the heavy chain, part of the F pocket of the antigen-binding groove. Dimerization of HLA-B27 during assembly has been implicated in disease onset. The purpose of this study was to investigate the factors that influence differences in dimerization between disease-associated and non-disease-associated HLA-B27 alleles. HLA-B*27:05 and mutants resembling the HLA-B*27:06 and 09 subtypes were expressed in the rat C58 T cell line, the human CEM T cell line and its calnexin-deficient variant CEM.NKR. Immunoprecipitation, pulse-chase experiments, flow cytometry, and immunoblotting were performed to study the assembly kinetics, heavy-chain dimerization, and chaperone associations. By expressing HLA-B*27:05, 06-like, and 09 alleles on a restrictive rat transporter associated with antigen processing background, we demonstrate that a tyrosine expressed at p116, either alone or together with an aspartic acid residue at p114, inhibited HLA-B27 dimerization and increased the assembly rate. F-pocket residues altered the associations with chaperones of the early major histocompatibility complex class I folding pathway. Calnexin was demonstrated to participate in endoplasmic reticulum (ER) stress-mediated degradation of dimers, whereas the oxidoreductase ERp57 does not appear to influence dimerization. Residues within the F pocket of the peptide-binding groove, which differ between disease-associated and non-disease-associated HLA-B27 subtypes, can influence the assembly process and heavy-chain dimerization, events which have been linked to the initiation of disease pathogenesis. © 2016, American College of Rheumatology.
Kinetics of the chiral phase transition
Energy Technology Data Exchange (ETDEWEB)
Hees, Hendrik van [Johann-Wolfgang-Goethe-Universitaet Frankfurt, Institut fuer Theoretische Physik, Frankfurt (Germany); Frankfurt Institute for Advanced Studies (FIAS), Frankfurt (Germany); Wesp, Christian; Meistrenko, Alex; Greiner, Carsten [Johann-Wolfgang-Goethe-Universitaet Frankfurt, Institut fuer Theoretische Physik, Frankfurt (Germany)
2016-07-01
We simulate the kinetics of the chiral phase transition in hot and dense strongly interacting matter within a novel kinetic-theory approach. Employing an effective linear σ model for quarks, σ mesons, and pions we treat the quarks within a test-particle ansatz for solving the Boltzmann transport equation and the mesons in terms of classical fields. The decay-recombination processes like σ <-> anti q+q are treated using a kind of wave-particle dualism using the exact conservation of energy and momentum. After demonstrating the correct thermodynamic limit for particles and fields in a ''box calculation'' we apply the simulation to the dynamics of an expanding fireball similar to the medium created in ultrarelativistic heavy-ion collisions.
Czech Academy of Sciences Publication Activity Database
Vavrinská, A.; Zelinka, J.; Šebera, Jakub; Sychrovský, Vladimír; Fiala, R.; Boelens, R.; Sklenář, V.; Trantírek, L.
2016-01-01
Roč. 64, č. 1 (2016), s. 53-62 ISSN 0925-2738 R&D Projects: GA ČR GA13-27676S Grant - others:AV ČR(CZ) M200551205 Institutional support: RVO:61388963 Keywords : NMR * DFT calculations * spin-spin interactions * magnetic field Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.410, year: 2016 http://link.springer.com/article/10.1007/s10858-015-0005-x
Energy Technology Data Exchange (ETDEWEB)
Ongonwou, F., E-mail: fred.ongonwou@gmail.com [Département de Physique, Faculté des Sciences, Université des Sciences et Techniques de Masuku, B.P. 943 Franceville (Gabon); Tetchou Nganso, H.M., E-mail: htetchou@yahoo.com [Atoms and Molecules Laboratory, Centre for Atomic Molecular Physics and Quantum Optics (CEPAMOQ), Faculty of Science, University of Douala, P.O. Box 8580, Douala (Cameroon); Ekogo, T.B., E-mail: tekogo@yahoo.fr [Département de Physique, Faculté des Sciences, Université des Sciences et Techniques de Masuku, B.P. 943 Franceville (Gabon); Kwato Njock, M.G., E-mail: mkwato@yahoo.com [Atoms and Molecules Laboratory, Centre for Atomic Molecular Physics and Quantum Optics (CEPAMOQ), Faculty of Science, University of Douala, P.O. Box 8580, Douala (Cameroon)
2016-12-15
In this study we present a model that we have formulated in the momentum space to describe atoms interacting with intense laser fields. As a further step, it follows our recent theoretical approach in which the kernel of the reciprocal-space time-dependent Schrödinger equation (TDSE) is replaced by a finite sum of separable potentials, each of them supporting one bound state of atomic hydrogen (Tetchou Nganso et al. 2013). The key point of the model is that the nonlocal interacting Coulomb potential is expanded in a Coulomb Sturmian basis set derived itself from a Sturmian representation of Bessel functions of the first kind in the position space. As a result, this decomposition allows a simple spectral treatment of the TDSE in the momentum space. In order to illustrate the credibility of the model, we have considered the test case of atomic hydrogen driven by a linearly polarized laser pulse, and have evaluated analytically matrix elements of the atomic Hamiltonian and dipole coupling interaction. For various regimes of the laser parameters used in computations our results are in very good agreement with data obtained from other time-dependent calculations.
Ongonwou, F.; Tetchou Nganso, H. M.; Ekogo, T. B.; Kwato Njock, M. G.
2016-12-01
In this study we present a model that we have formulated in the momentum space to describe atoms interacting with intense laser fields. As a further step, it follows our recent theoretical approach in which the kernel of the reciprocal-space time-dependent Schrödinger equation (TDSE) is replaced by a finite sum of separable potentials, each of them supporting one bound state of atomic hydrogen (Tetchou Nganso et al. 2013). The key point of the model is that the nonlocal interacting Coulomb potential is expanded in a Coulomb Sturmian basis set derived itself from a Sturmian representation of Bessel functions of the first kind in the position space. As a result, this decomposition allows a simple spectral treatment of the TDSE in the momentum space. In order to illustrate the credibility of the model, we have considered the test case of atomic hydrogen driven by a linearly polarized laser pulse, and have evaluated analytically matrix elements of the atomic Hamiltonian and dipole coupling interaction. For various regimes of the laser parameters used in computations our results are in very good agreement with data obtained from other time-dependent calculations.
Vereshchagin, Gregory V.; Aksenov, Alexey G.
2017-02-01
Preface; Acknowledgements; Acronyms and definitions; Introduction; Part I. Theoretical Foundations: 1. Basic concepts; 2. Kinetic equation; 3. Averaging; 4. Conservation laws and equilibrium; 5. Relativistic BBGKY hierarchy; 6. Basic parameters in gases and plasmas; Part II. Numerical Methods: 7. The basics of computational physics; 8. Direct integration of Boltzmann equations; 9. Multidimensional hydrodynamics; Part III. Applications: 10. Wave dispersion in relativistic plasma; 11. Thermalization in relativistic plasma; 12. Kinetics of particles in strong fields; 13. Compton scattering in astrophysics and cosmology; 14. Self-gravitating systems; 15. Neutrinos, gravitational collapse and supernovae; Appendices; Bibliography; Index.
Pöschl, U.; Rudich, Y.; Ammann, M.
2007-12-01
Aerosols and clouds play central roles in atmospheric chemistry and physics, climate, air pollution, and public health. The mechanistic understanding and predictability of aerosol and cloud properties, interactions, transformations, and effects are, however, still very limited. This is due not only to the limited availability of measurement data, but also to the limited applicability and compatibility of model formalisms used for the analysis, interpretation, and description of heterogeneous and multiphase processes. To support the investigation and elucidation of atmospheric aerosol and cloud surface chemistry and gas-particle interactions, we present a comprehensive kinetic model framework with consistent and unambiguous terminology and universally applicable rate equations and parameters. It enables a detailed description of mass transport and chemical reactions at the gas-particle interface, and it allows linking aerosol and cloud surface processes with gas phase and particle bulk processes in systems with multiple chemical components and competing physicochemical processes. The key elements and essential aspects of the presented framework are: a simple and descriptive double-layer surface model (sorption layer and quasi-static layer); straightforward flux-based mass balance and rate equations; clear separation of mass transport and chemical reactions; well-defined and consistent rate parameters (uptake and accommodation coefficients, reaction and transport rate coefficients); clear distinction between gas phase, gas-surface, and surface-bulk transport (gas phase diffusion, surface and bulk accommodation); clear distinction between gas-surface, surface layer, and surface-bulk reactions (Langmuir-Hinshelwood and Eley-Rideal mechanisms); mechanistic description of concentration and time dependences (transient and steady-state conditions); flexible addition of unlimited numbers of chemical species and physicochemical processes; optional aggregation or resolution
Onda, Ken; Ogihara, Sho; Yonemitsu, Kenji; Maeshima, Nobuya; Ishikawa, Tadahiko; Okimoto, Yoichi; Shao, Xiangfeng; Nakano, Yoshiaki; Yamochi, Hideki; Saito, Gunzi; Koshihara, Shin-Ya
2008-08-01
The quasistable state in the photoinduced phase transition for the quasi-one-dimensional quarter-filled organic conductor (EDO-TTF)2PF6 has been examined by ultrafast reflective measurements and time-dependent model calculations incorporating both electron-electron and electron-phonon interactions. The transient optical conductivity spectrum over a wide probe photon-energy range revealed that photoexcitation induced a new type of charge-disproportionate state. Additionally, coherent and incoherent oscillations dependent on probe photon energies were found, as predicted by the calculation.
Strong-strong beam-beam simulation on parallel computer
Energy Technology Data Exchange (ETDEWEB)
Qiang, Ji
2004-08-02
The beam-beam interaction puts a strong limit on the luminosity of the high energy storage ring colliders. At the interaction points, the electromagnetic fields generated by one beam focus or defocus the opposite beam. This can cause beam blowup and a reduction of luminosity. An accurate simulation of the beam-beam interaction is needed to help optimize the luminosity in high energy colliders.
Strong-strong beam-beam simulation on parallel computer
International Nuclear Information System (INIS)
Qiang, Ji
2004-01-01
The beam-beam interaction puts a strong limit on the luminosity of the high energy storage ring colliders. At the interaction points, the electromagnetic fields generated by one beam focus or defocus the opposite beam. This can cause beam blowup and a reduction of luminosity. An accurate simulation of the beam-beam interaction is needed to help optimize the luminosity in high energy colliders
Kumar, Vineet; Dixit, Nitin; Zhou, Liqiang Lisa; Fraunhofer, Wolfgang
2011-12-12
The purpose of this work was to determine the nature of long and short-range forces governing protein aggregation kinetics at low and high concentrations for a monoclonal antibody (IgG1) and a dual-variable-domain immunoglobulin (DVD-Ig). Protein-protein interactions (PPI) were studied under dilute conditions by utilizing the methods of static (B(22)) and dynamic light scattering (k(D)). PPI in solutions containing minimal ionic strengths were characterized to get detailed insights into the impact of ionic strength on aggregation. Microcalorimetry and susceptibility to denature at air-liquid interface were used to assess the tertiary structure and quiescent stability studies were conducted to study aggregation characteristics. Results for IgG1 showed that electrostatic interactions governed protein aggregation kinetics both under dilute and concentrated conditions (i.e., 5 mg/mL and 150 mg/mL). For DVD-Ig molecules, on the other hand, although electrostatic interactions governed protein aggregation under dilute conditions, hydrophobic forces clearly determined the kinetics at high concentrations. This manuscript shows for the first time that short-range hydrophobic interactions can outweigh electrostatic forces and play an important role in determining protein aggregation at high concentrations. Additionally, results show that although higher-order virial coefficients become significant under low ionic strength conditions, removal of added charges may be used to enhance the aggregation stability of dilute protein formulations. Copyright © 2011 Elsevier B.V. All rights reserved.
Adsorption analysis equilibria and kinetics
Do, Duong D
1998-01-01
This book covers topics of equilibria and kinetics of adsorption in porous media. Fundamental equilibria and kinetics are dealt with for homogeneous as well as heterogeneous particles. Five chapters of the book deal with equilibria and eight chapters deal with kinetics. Single component as well as multicomponent systems are discussed. In kinetics analysis, we deal with the various mass transport processes and their interactions inside a porous particle. Conventional approaches as well as the new approach using Maxwell-Stefan equations are presented. Various methods to measure diffusivity, such
Kinetics of protein unfolding at interfaces
International Nuclear Information System (INIS)
Yano, Yohko F
2012-01-01
The conformation of protein molecules is determined by a balance of various forces, including van der Waals attraction, electrostatic interaction, hydrogen bonding, and conformational entropy. When protein molecules encounter an interface, they are often adsorbed on the interface. The conformation of an adsorbed protein molecule strongly depends on the interaction between the protein and the interface. Recent time-resolved investigations have revealed that protein conformation changes during the adsorption process due to the protein-protein interaction increasing with increasing interface coverage. External conditions also affect the protein conformation. This review considers recent dynamic observations of protein adsorption at various interfaces and their implications for the kinetics of protein unfolding at interfaces. (topical review)
DEFF Research Database (Denmark)
Buch, Line Hjortø; Sørensen, Morten Kargo; Berg, Peer
2012-01-01
) a positive interaction exists between the use of genotypic information and a short generation interval on ΔGAG and (iii) the inclusion of an indicator trait in the selection index will only result in a negligible increase in ΔGAG if genotypic information about the breeding goal trait is known. We examined......We tested the following hypotheses: (i) breeding schemes with genomic selection are superior to breeding schemes without genomic selection regarding annual genetic gain of the aggregate genotype (ΔGAG), annual genetic gain of the functional traits and rate of inbreeding per generation (ΔF), (ii...... four breeding schemes with or without genomic selection and with or without intensive use of young bulls using pseudo-genomic stochastic simulations. The breeding goal consisted of a milk production trait and a functional trait. The two breeding schemes with genomic selection resulted in higher ΔGAG...
Energy Technology Data Exchange (ETDEWEB)
Moretto-Capelle, P.; Benhenni, M.; Bordenave-Montesquieu, D.; Bordenave-Montesquieu, A. [Toulouse-3 Univ., 31 (France)
1996-05-28
The three-body post-collisional interaction (PCI) between the scattered proton, recoil target ion and emitted electron has been investigated by electron spectrometry near the 2l2l` helium resonances, in the 20-100 keV energy range (V{sub p} 0.9-2 au). Particular attention has been paid to the PCI deformations of the Fano lineshapes when V-vector``{sub p} {approx_equal} V-vector {sub e}(2l2l`). Their angle and collision velocity dependences have been studied for the first time experimentally. A large variety of lineshapes have been observed, all of them successfully described by a single formula. At the lowest proton velocities the rescattering effect (also called Coulomb two-path scattering) is seen. (Author).
Plasmons in strong superconductors
International Nuclear Information System (INIS)
Baldo, M.; Ducoin, C.
2011-01-01
We present a study of the possible plasmon excitations that can occur in systems where strong superconductivity is present. In these systems the plasmon energy is comparable to or smaller than the pairing gap. As a prototype of these systems we consider the proton component of Neutron Star matter just below the crust when electron screening is not taken into account. For the realistic case we consider in detail the different aspects of the elementary excitations when the proton, electron components are considered within the Random-Phase Approximation generalized to the superfluid case, while the influence of the neutron component is considered only at qualitative level. Electron screening plays a major role in modifying the proton spectrum and spectral function. At the same time the electron plasmon is strongly modified and damped by the indirect coupling with the superfluid proton component, even at moderately low values of the gap. The excitation spectrum shows the interplay of the different components and their relevance for each excitation modes. The results are relevant for neutrino physics and thermodynamical processes in neutron stars. If electron screening is neglected, the spectral properties of the proton component show some resemblance with the physical situation in high-T c superconductors, and we briefly discuss similarities and differences in this connection. In a general prospect, the results of the study emphasize the role of Coulomb interaction in strong superconductors.
Lyons, T P; Okano, C K; Kuhnle, J A; Bruins, M R; Darwin, W D; Moolchan, E T; Huestis, M A
2001-10-01
In this study, we investigated the effectiveness of the Roche Kinetic Interaction of Microparticles in Solution (KIMS) screening assay for cannabinoid metabolites. Urine specimens (N = 1689) were collected during elimination of cannabinoids from 25 subjects with a history of marijuana use. Specimens were analyzed concurrently for cannabinoid metabolites by a customized Department of Defense (DOD) cannabinoid KIMS kit (50-ng/mL cutoff) and for 11-nor-9-carboxy-delta9-tetrahydrocannabinol (THC-COOH) by GC-MS (15-ng/mL cutoff). As compared to GC-MS results, the sensitivity, specificity, and efficiency of the KIMS assay were 69.7%, 99.8%, and 88.6%, respectively. Many of the false-negative results had GC-MS concentrations between 15 and 26 ng/mL (N = 151). The cannabinoid screening results for the DOD samples tested by the laboratory during the same 8-month period were also evaluated. The linear regression analyses of GC-MS results in the 15-50 ng/mL range and KIMS data resulted in regression coefficients of 0.689 for the research specimens and 0.546 for DOD specimens. The results suggest that the KIMS cannabinoid screening assay is deficient in detecting positives around the cutoff (15-25 ng/mL THC-COOH). This limitation of the KIMS cannabinoid screening method compromises the identification of true positive specimens, therefore reducing the effectiveness of the assay. The success of the DOD program is dependent on sensitive and specific screening assays; the high prevalence of false-negative cannabinoid results compromises the program's primary objective of drug deterrence.
York, Larry M; Silberbush, Moshe; Lynch, Jonathan P
2016-06-01
Increasing maize nitrogen acquisition efficiency is a major goal for the 21st century. Nitrate uptake kinetics (NUK) are defined by I max and K m, which denote the maximum uptake rate and the affinity of transporters, respectively. Because NUK have been studied predominantly at the molecular and whole-root system levels, little is known about the functional importance of NUK variation within root systems. A novel method was created to measure NUK of root segments that demonstrated variation in NUK among root classes (seminal, lateral, crown, and brace). I max varied among root class, plant age, and nitrate deprivation combinations, but was most affected by plant age, which increased I max, and nitrate deprivation time, which decreased I max K m was greatest for crown roots. The functional-structural simulation SimRoot was used for sensitivity analysis of plant growth to root segment I max and K m, as well as to test interactions of I max with root system architectural phenes. Simulated plant growth was more sensitive to I max than K m, and reached an asymptote near the maximum I max observed in the empirical studies. Increasing the I max of lateral roots had the largest effect on shoot growth. Additive effects of I max and architectural phenes on nitrate uptake were observed. Empirically, only lateral root tips aged 20 d operated at the maximum I max, and simulations demonstrated that increasing all seminal and lateral classes to this maximum rate could increase plant growth by as much as 26%. Therefore, optimizing I max for all maize root classes merits attention as a promising breeding goal. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.
Zhang, R.; Zhang, X.; Hu, S.
2013-12-01
C. The rSi, Mx occurred at 300°C. rAl, Mx is at 374°C and rK, Mx is near at 350°C, rCa, Mx and rFe, Mx are at 200°C and rMg, Mx is at 100°C. The upper-middle crust is usually at T range from 300 to 450°C, where, high conductivity zone occurs. Geophysical survey indicated that plate collision are ultimately responsible for inducing horizontal faults, detachments (cracking), generating porosity, decreasing pressure, and moving fluids through continents. These processes probably lead to the migration of aqueous fluid in the mid-crust accompanying pressure lowering (possible close to the critical state of aqueous solution) at 300 to 450°C. Therefore, strong water rock interactions occur in mid-crust, cause strong leaching of Si, breakage of silicate framework and rock collapse. Those reactions will further lead to increase rock porosity and drive fluid flow. Those events take important role in enhancing the electric conductivity of rocks in the mid-crust. Simultaneously, water and NaCl-H2O at 350-450°C in the mid crust have high electric conductivity. Key words: chemical kinetics, critical state, basalt-water interaction, electric conductance, high conductivity zone, high temperature experiment.
Energy Technology Data Exchange (ETDEWEB)
Glowacki, David R., E-mail: drglowacki@gmail.com [School of Chemistry, University of Bristol, Bristol BS8 1TS (United Kingdom); Department of Computer Science, University of Bristol, Bristol BS8 1UB (United Kingdom); PULSE Institute and Department of Chemistry, Stanford University, Stanford, California 94305 (United States); SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Orr-Ewing, Andrew J. [School of Chemistry, University of Bristol, Bristol BS8 1TS (United Kingdom); Harvey, Jeremy N. [Department of Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001 Heverlee (Belgium)
2015-07-28
We describe a parallelized linear-scaling computational framework developed to implement arbitrarily large multi-state empirical valence bond (MS-EVB) calculations within CHARMM and TINKER. Forces are obtained using the Hellmann-Feynman relationship, giving continuous gradients, and good energy conservation. Utilizing multi-dimensional Gaussian coupling elements fit to explicitly correlated coupled cluster theory, we built a 64-state MS-EVB model designed to study the F + CD{sub 3}CN → DF + CD{sub 2}CN reaction in CD{sub 3}CN solvent (recently reported in Dunning et al. [Science 347(6221), 530 (2015)]). This approach allows us to build a reactive potential energy surface whose balanced accuracy and efficiency considerably surpass what we could achieve otherwise. We ran molecular dynamics simulations to examine a range of observables which follow in the wake of the reactive event: energy deposition in the nascent reaction products, vibrational relaxation rates of excited DF in CD{sub 3}CN solvent, equilibrium power spectra of DF in CD{sub 3}CN, and time dependent spectral shifts associated with relaxation of the nascent DF. Many of our results are in good agreement with time-resolved experimental observations, providing evidence for the accuracy of our MS-EVB framework in treating both the solute and solute/solvent interactions. The simulations provide additional insight into the dynamics at sub-picosecond time scales that are difficult to resolve experimentally. In particular, the simulations show that (immediately following deuterium abstraction) the nascent DF finds itself in a non-equilibrium regime in two different respects: (1) it is highly vibrationally excited, with ∼23 kcal mol{sup −1} localized in the stretch and (2) its post-reaction solvation environment, in which it is not yet hydrogen-bonded to CD{sub 3}CN solvent molecules, is intermediate between the non-interacting gas-phase limit and the solution-phase equilibrium limit. Vibrational
International Nuclear Information System (INIS)
Glowacki, David R.; Orr-Ewing, Andrew J.; Harvey, Jeremy N.
2015-01-01
We describe a parallelized linear-scaling computational framework developed to implement arbitrarily large multi-state empirical valence bond (MS-EVB) calculations within CHARMM and TINKER. Forces are obtained using the Hellmann-Feynman relationship, giving continuous gradients, and good energy conservation. Utilizing multi-dimensional Gaussian coupling elements fit to explicitly correlated coupled cluster theory, we built a 64-state MS-EVB model designed to study the F + CD 3 CN → DF + CD 2 CN reaction in CD 3 CN solvent (recently reported in Dunning et al. [Science 347(6221), 530 (2015)]). This approach allows us to build a reactive potential energy surface whose balanced accuracy and efficiency considerably surpass what we could achieve otherwise. We ran molecular dynamics simulations to examine a range of observables which follow in the wake of the reactive event: energy deposition in the nascent reaction products, vibrational relaxation rates of excited DF in CD 3 CN solvent, equilibrium power spectra of DF in CD 3 CN, and time dependent spectral shifts associated with relaxation of the nascent DF. Many of our results are in good agreement with time-resolved experimental observations, providing evidence for the accuracy of our MS-EVB framework in treating both the solute and solute/solvent interactions. The simulations provide additional insight into the dynamics at sub-picosecond time scales that are difficult to resolve experimentally. In particular, the simulations show that (immediately following deuterium abstraction) the nascent DF finds itself in a non-equilibrium regime in two different respects: (1) it is highly vibrationally excited, with ∼23 kcal mol −1 localized in the stretch and (2) its post-reaction solvation environment, in which it is not yet hydrogen-bonded to CD 3 CN solvent molecules, is intermediate between the non-interacting gas-phase limit and the solution-phase equilibrium limit. Vibrational relaxation of the nascent DF results
Glowacki, David R; Orr-Ewing, Andrew J; Harvey, Jeremy N
2015-07-28
We describe a parallelized linear-scaling computational framework developed to implement arbitrarily large multi-state empirical valence bond (MS-EVB) calculations within CHARMM and TINKER. Forces are obtained using the Hellmann-Feynman relationship, giving continuous gradients, and good energy conservation. Utilizing multi-dimensional Gaussian coupling elements fit to explicitly correlated coupled cluster theory, we built a 64-state MS-EVB model designed to study the F + CD3CN → DF + CD2CN reaction in CD3CN solvent (recently reported in Dunning et al. [Science 347(6221), 530 (2015)]). This approach allows us to build a reactive potential energy surface whose balanced accuracy and efficiency considerably surpass what we could achieve otherwise. We ran molecular dynamics simulations to examine a range of observables which follow in the wake of the reactive event: energy deposition in the nascent reaction products, vibrational relaxation rates of excited DF in CD3CN solvent, equilibrium power spectra of DF in CD3CN, and time dependent spectral shifts associated with relaxation of the nascent DF. Many of our results are in good agreement with time-resolved experimental observations, providing evidence for the accuracy of our MS-EVB framework in treating both the solute and solute/solvent interactions. The simulations provide additional insight into the dynamics at sub-picosecond time scales that are difficult to resolve experimentally. In particular, the simulations show that (immediately following deuterium abstraction) the nascent DF finds itself in a non-equilibrium regime in two different respects: (1) it is highly vibrationally excited, with ∼23 kcal mol(-1) localized in the stretch and (2) its post-reaction solvation environment, in which it is not yet hydrogen-bonded to CD3CN solvent molecules, is intermediate between the non-interacting gas-phase limit and the solution-phase equilibrium limit. Vibrational relaxation of the nascent DF results in a spectral
DEFF Research Database (Denmark)
2009-01-01
A kinetic interface for orientation detection in a video training system is disclosed. The interface includes a balance platform instrumented with inertial motion sensors. The interface engages a participant's sense of balance in training exercises.......A kinetic interface for orientation detection in a video training system is disclosed. The interface includes a balance platform instrumented with inertial motion sensors. The interface engages a participant's sense of balance in training exercises....
Hydrogen interaction kinetics of Ge dangling bonds at the Si0.25Ge0.75/SiO2 interface
International Nuclear Information System (INIS)
Stesmans, A.; Nguyen Hoang, T.; Afanas'ev, V. V.
2014-01-01
The hydrogen interaction kinetics of the GeP b1 defect, previously identified by electron spin resonance (ESR) as an interfacial Ge dangling bond (DB) defect occurring in densities ∼7 × 10 12 cm −2 at the SiGe/SiO 2 interfaces of condensation grown (100)Si/a-SiO 2 /Ge 0.75 Si 0.25 /a-SiO 2 structures, has been studied as function of temperature. This has been carried out, both in the isothermal and isochronal mode, through defect monitoring by capacitance-voltage measurements in conjunction with ESR probing, where it has previously been demonstrated the defects to operate as negative charge traps. The work entails a full interaction cycle study, comprised of analysis of both defect passivation (pictured as GeP b1 -H formation) in molecular hydrogen (∼1 atm) and reactivation (GeP b1 -H dissociation) in vacuum. It is found that both processes can be suitably described separately by the generalized simple thermal (GST) model, embodying a first order interaction kinetics description based on the basic chemical reactions GeP b1 + H 2 → GeP b1 H + H and GeP b1 H → GeP b1 + H, which are found to be characterized by the average activation energies E f = 1.44 ± 0.04 eV and E d = 2.23 ± 0.04 eV, and attendant, assumedly Gaussian, spreads σE f = 0.20 ± 0.02 eV and σE d = 0.15 ± 0.02 eV, respectively. The substantial spreads refer to enhanced interfacial disorder. Combination of the separately inferred kinetic parameters for passivation and dissociation results in the unified realistic GST description that incorporates the simultaneous competing action of passivation and dissociation, and which is found to excellently account for the full cycle data. For process times t a ∼ 35 min, it is found that even for the optimum treatment temperature ∼380 °C, only ∼60% of the GeP b1 system can be electrically silenced, still far remote from device grade level. This
Moravcova, Radka; Melkes, Barbora; Novotny, Jiri
2018-02-01
Extensive research has been dedicated to elucidating the mechanisms of signal transduction through different G protein-coupled receptors (GPCRs). However, relatively little is known about the regulation of receptor movement within the cell membrane upon ligand binding. In this study we focused our attention on the thyrotropin-releasing hormone (TRH) receptor that typically couples to G q/11 proteins. We monitored receptor diffusion in the plasma membrane of HEK293 cells stably expressing yellow fluorescent protein (YFP)-tagged TRH receptor (TRHR-YFP) by fluorescence recovery after photobleaching (FRAP). FRAP analysis indicated that the lateral movement of the TRH receptor was markedly reduced upon TRH binding as the value of its diffusion coefficient fell down by 55%. This effect was prevented by the addition of the TRH receptor antagonist midazolam. We also found that siRNA-mediated knockdown of G q/11 α, Gβ, β-arrestin2 and phospholipase Cβ1, but not of G i α1, β-arrestin1 or G protein-coupled receptor kinase 2, resulted in a significant decrease in the rate of TRHR-YFP diffusion, indicating the involvement of the former proteins in the regulation of TRH receptor behavior. The observed partial reduction of the TRHR-YFP mobile fraction caused by down-regulation of G i α1 and β-arrestin1 suggests that these proteins may also play distinct roles in THR receptor-mediated signaling. These results demonstrate for the first time that not only agonist binding but also abundance of some signaling proteins may strongly affect TRH receptor dynamics in the plasma membrane.