title stringlengths 0 1.13k | abstract stringlengths 1 15.7k | PMID int64 22 36.5M |
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Retention of proteins and metalloproteins in open tubular capillary electrochromatography with etched chemically modified columns. | Etched chemically modified capillaries with two different bonded groups (pentyl and octadecyl) are compared for their migration behavior of several common proteins and metalloproteins as well as metalloproteinases. Migration times, efficiency and peak shape are evaluated over the pH range of 2.1-8.1 to determine any ef... | 18,850,653 |
Elimination of exemptions for chemical mixtures containing the list I chemicals ephedrine and/or pseudoephedrine. Final rule. | The Drug Enforcement Administration (DEA) is finalizing, without change, the Interim Rule with Request for Comment published in the Federal Register on July 25, 2007 (72 FR 40738). The Interim Rule removed the Controlled Substances Act (CSA) exemptions for chemical mixtures containing ephedrine and/or pseudoephedrine w... | 18,850,676 |
Synthesis of atomic gold clusters with strong electrocatalytic activities. | Small atomic gold clusters in solution, Au n , stabilized by tetrabutyl ammonium bromide (TBABr), have been synthesized by a simple electrochemical technique, based on the anodic dissolution of a gold electrode in the presence of TBABr salt, and using acetronitrile as solvent. The presence of clusters in the range Au3-... | 18,850,689 |
Complex Langmuir-Blodgett films of SiO2 and ZnO nanoparticles with advantageous optical and photocatalytical properties. | Multifunctional Langmuir-Blodgett (LB) films were fabricated on the surface of glass substrates using sol-gel derived ZnO and SiO2 particles. ZnO particles of 6 and 110 nm diameter were synthesized according to the methods of Meulenkamp and Seelig et al. (Meulenkamp, E. A. J. Phys. Chem. B 1998, 102, 5566; Seelig, E. W... | 18,850,690 |
Relay catalysis by a metal-complex/Brønsted acid binary system in a tandem isomerization/carbon-carbon bond forming sequence. | A one-pot tandem isomerization/carbon-carbon bond forming sequence catalyzed by a ruthenium complex/Brønsted acid binary system is demonstrated. The method enables the use of readily available allylamides to deliver reactive imines under relay catalysis using a binary catalytic system. Subsequent Brønsted acid catalyze... | 18,850,704 |
Adsorption effect on the degradation of carbaryl, mecoprop, and paraquat by anodic fenton treatment in an SWy-2 montmorillonite clay slurry. | The Fenton reaction-based anodic Fenton treatment (AFT) was applied to three widely used organic agrochemicals, carbaryl, mecoprop, and paraquat, in a clay slurry. The adsorption and degradation behaviors of these neutral (carbaryl), anionic (mecoprop), and cationic (paraquat) agrochemicals were studied in a slurry of ... | 18,850,712 |
Isolated glycosaminoglycans from cooked haddock enhance nonheme iron uptake by Caco-2 cells. | This study continues previous research to confirm that glycosaminoglycans (GAGs) exert a positive effect on promoting iron uptake by Caco-2 cells. Cooked haddock was digested with papain, and GAGs were further purified on the basis of their sulfur content. Reverse phase chromatography (RP-HPLC) and digestion with chond... | 18,850,715 |
Comprehensive two-dimensional gas chromatography combustion isotope ratio mass spectrometry. | We report the first coupling of comprehensive two-dimensional gas chromatography (GC x GC) to online combustion isotope ratio mass spectrometry (C-IRMS). A GC x GC system, equipped with a longitudinally modulated cryogenic system (LMCS), was interfaced to an optimized low dead volume combustion interface to preserve &l... | 18,850,725 |
Aggregation of nanosized colloidal silica in the presence of various alkali cations investigated by the electrospray technique. | The slow aggregation process of a concentrated silica dispersion (Bindzil 40/220) in the presence of alkali chlorides (LiCl, NaCl, KCl, RbCl, and CsCl) was investigated by means of mobility measurements. At intervals during the aggregation, particles and aggregates were transferred from the liquid phase to the gas phas... | 18,850,727 |
A scalable synthesis of an azabicyclooctanyl derivative, a novel DPP-4 inhibitor. | A practical synthetic strategy to a chiral azabicycclooctanyl derivative (1), a potent DPP-4 inhibitor, starting from a commercially available nortropine is described. The stereogenic center of 1 was established employing a modified protocol of Ellman's diastereoselective addition of a benzylic nucleophile to tert-buta... | 18,850,743 |
A review of health-utility data for osteoarthritis: implications for clinical trial-based evaluation. | The objective of this review was to describe the performance of health-utility measures in valuing the quality-of-life (QOL) impact of changes in osteoarthritis (OA)-related chronic pain when administered within a clinical trial setting. Because the collection of utility data within a clinical trial is not always feasi... | 18,850,762 |
Violation of the action-reaction principle and self-forces induced by nonequilibrium fluctuations. | We show that the extension of Casimir-like forces to fluctuating fluids driven out of equilibrium can exhibit two interrelated phenomena forbidden at equilibrium: self-forces can be induced on single asymmetric objects and the action-reaction principle between two objects can be violated. These effects originate in asy... | 18,850,772 |
Simulation of dendritic growth into an undercooled melt using kinetic Monte Carlo techniques. | We consider the growth of a single fcc dendrite into an undercooled melt. Unlike most simulations of this well-studied phenomenon, we adopt an atomistic growth model that uses a kinetic Monte Carlo technique to track the free boundary. The model allows for both phase change and exchange between liquid and solid atoms o... | 18,850,777 |
Fluctuation theorem for the renormalized entropy change in the strongly nonlinear nonequilibrium regime. | A nonlinear relaxation process is considered for a macroscopic thermodynamic quantity, generalizing recent work by Taniguchi and Cohen [J. Stat. Phys. 126, 1 (2006)] that was based on the Onsager-Machlup theory. It is found that the fluctuation theorem holds in the nonlinear nonequilibrium regime if the change of entro... | 18,850,780 |
Random fiber bundle with many discontinuities in the threshold distribution. | We study the breakdown of a random fiber bundle model (RFBM) with n discontinuities in the threshold distribution using the global load sharing scheme. In other words, n+1 different classes of fibers identified on the basis of their threshold strengths are mixed such that the strengths of the fibers in the ith class ar... | 18,850,797 |
Numerical diagonalization analysis of the criticality of the (2+1)-dimensional XY model: off-diagonal Novotny's method. | The criticality of the (2+1)-dimensional XY model is investigated with the numerical diagonalization method. So far, it has been considered that the diagonalization method would not be very suitable for analyzing the criticality in large dimensions (d> or =3) ; in fact, the tractable system size with the diagonaliza... | 18,850,814 |
Molière theory of multiple Coulomb scattering with ionization and the transport mechanism of the multiple scattering process. | The Molière theory of multiple Coulomb scattering is improved to take account of ionization loss by applying a differential formulation of the theory. Distributions for the deflection angle theta over, as well as for any linear combination between theta over and the lateral displacement r over, under the ionization pro... | 18,850,815 |
Barchan dunes in two dimensions: experimental tests for minimal models. | A well-defined two-dimensional single barchan dune under the force of a shearing water flow is investigated experimentally. From an initially prepared triangular heap a rapid relaxation to a steady-state solution is observed with constant mass, shape, and velocity. This attractor exhibits all characteristic features of... | 18,850,828 |
Third-order thermodynamic perturbation theory for effective potentials that model complex fluids. | We have performed Monte Carlo simulations to obtain the thermodynamic properties of fluids with two kinds of hard-core plus attractive-tail or oscillatory potentials. One of them is the square-well potential with small well width. The other is a model potential with oscillatory and decaying tail. Both model potentials ... | 18,850,837 |
Spatiotemporal nematodynamics in wormlike micelles en route to rheochaos. | We show through polarized light scattering experiments the spatially inhomogeneous orientational dynamics for shear-thinning wormlike micellar gels (cetyltrimethylammonium tosylate+sodium chloride+H2O ) en route to rheochaos. For shear rates in the plateau of the flow curve, we see alternating bright and dark birefring... | 18,850,838 |
Shear-induced tilt in smectic-A elastomers. | Smectic-A elastomers combine the positional long-range order of mesogenic molecules in one dimension with the rubber elasticity of a polymer network. While the influence of uniaxial mechanical fields on the phase structure has been investigated intensively during recent years, the impact of shear forces on the orientat... | 18,850,849 |
Surface-induced morphology and free-energy pathways in breakup of a nematic liquid crystalline cylinder. | We compute the surface-induced morphology and the free-energy pathways as a cylindrical liquid crystalline filament with preferred homeotropic (orthogonal) interface orientation passes through a sequence of growing sinusoidal perturbations and breaks up into droplets. Liquid crystalline morphology is determined using a... | 18,850,851 |
Membrane lipid segregation in endocytosis. | We explore the equilibrium mechanics of a binary lipid membrane that wraps around a spherical or cylindrical particle. One of the lipid membrane components induces a positive spontaneous curvature, while the other induces a negative local curvature. Using a Hamiltonian approach, we derive the equations governing the me... | 18,850,866 |
Optimum size of a molecular bond cluster in adhesion. | The strength of a bonded interface is considered for the case in which bonding is the result of clusters of discrete bonds distributed along the interface. Assumptions appropriate for the case of adhesion of biological cells to an extracellular matrix are introduced as a basis for the discussion. It is observed that th... | 18,850,867 |
Driving neural oscillations with correlated spatial input and topographic feedback. | We consider how oscillatory activity in networks of excitable systems depends on spatial correlations of random inputs and the spatial range of feedback coupling. Analysis of a neural field model with topographic delayed recurrent feedback reveals how oscillations in certain frequency bands, including the gamma band, a... | 18,850,869 |
Characterization of multiple spiral wave dynamics as a stochastic predator-prey system. | A perspective on systems containing many action potential waves that, individually, are prone to spiral wave breakup is proposed. The perspective is based on two quantities, "predator" and "prey," which we define as the fraction of the system in the excited state and in the excitable but unexcited state, respectively. ... | 18,850,871 |
Solutions of the Maxwell viscoelastic equations for displacement and stress distributions within the arterial wall. | Mechanical events within the thickness of the vessel wall caused by pulsatile blood flow are considered, with focus on axial dynamics of the wall, driven by the oscillatory drag force exerted by the fluid on the endothelial layer of the wall. It is shown that the focus on the axial direction makes it possible to derive... | 18,850,872 |
Phase synchronization in mutually coupled chaotic diode lasers. | Semiconductor lasers with optical feedback have chaotically pulsating output behavior. When two similar chaotic lasers are optically coupled, they can become synchronized in their optical fluctuations. Here we show that the synchronization is not only in the amplitude and in the timing of the pulses but that the short ... | 18,850,883 |
Turing instability in reaction-subdiffusion systems. | We determine the conditions for the occurrence of Turing instabilities in activator-inhibitor systems, where one component undergoes subdiffusion and the other normal diffusion. If the subdiffusing species has a nonlinear death rate, then coupling between the nonlinear kinetics and the memory effects of the non-Markovi... | 18,850,906 |
Interface-selected waves and their influence on wave competition. | In this paper we study nonlinear oscillatory systems consisting of two media, one supporting forward propagating waves and the other inwardly propagating waves, separated by an interface. We find that the interface can select the type of wave. Under certain well-defined parameter condition, these waves propagate in two... | 18,850,916 |
Torus doubling resonances and breather stability. | Discrete breathers that arise in doped alkali halides lead us to study two properties of these localized excitations. First, we note a bifurcation phenomenon, which we dub torus doubling, in which resonant coupling in the nonlinear modes induces a period doubling of the phase space structure. Second, we find that altho... | 18,850,926 |
Testing for Markovian character and modeling of intermittency in solar wind turbulence. | We present results of statistical analysis of solar wind turbulence using an approach based on the theory of Markov processes. It is shown that the Chapman-Kolmogorov equation is approximately satisfied for the turbulent cascade. We evaluate the first two Kramers-Moyal coefficients from experimental data and show that ... | 18,850,953 |
Transverse stability of solitary waves propagating in coupled nonlinear dispersive transmission lines. | In the semidiscrete limit and in suitably scaled coordinates, the voltage of a system of coupled nonlinear dispersive transmission lines is described by a nonlinear Schrödinger equation. This equation is used to study the transverse stability of solitary waves of the system. Exact results for the growth rate and the co... | 18,850,958 |
Unified approach to split absorbing boundary conditions for nonlinear Schrödinger equations. | An efficient method is proposed for numerical solutions of nonlinear Schrödinger equations on an unbounded domain. Through approximating the kinetic energy term by a one-way equation and uniting it with the potential energy equation, absorbing boundary conditions are designed to truncate the unbounded domain, which are... | 18,850,975 |
Elasticity-mediated nematiclike bacterial organization in model extracellular DNA matrix. | DNA is a common extracellular matrix component of bacterial biofilms. We find that bacteria can spontaneously order in a matrix of aligned concentrated DNA, in which rod-shaped cells of Pseudomonas aeruginosa follow the orientation of extended DNA chains. The alignment of bacteria is ensured by elasticity and liquid cr... | 18,850,984 |
No many-scallop theorem: collective locomotion of reciprocal swimmers. | To achieve propulsion at low Reynolds number, a swimmer must deform in a way that is not invariant under time-reversal symmetry; this result is known as the scallop theorem. However, there is no many-scallop theorem. We demonstrate here that two active particles undergoing reciprocal deformations can swim collectively;... | 18,850,986 |
Cavity approach to the spectral density of sparse symmetric random matrices. | The spectral density of various ensembles of sparse symmetric random matrices is analyzed using the cavity method. We consider two cases: matrices whose associated graphs are locally treelike, and sparse covariance matrices. We derive a closed set of equations from which the density of eigenvalues can be efficiently ca... | 18,851,002 |
Ehrenfest model for condensation and evaporation processes in degrading aggregates with multiple bonds. | We present an explicit theory of the degradation and thermal fragmentation kinetics of polymerlike systems and aggregates with multiple bonds in the presence of stochastic evaporation and condensation (restoration) of bonds. The analysis is conducted on the basis of the determination of the first passage time to state ... | 18,851,003 |
Dynamics and structure of an aging binary colloidal glass. | We study aging in a colloidal suspension consisting of micron-sized particles in a liquid. This system is made glassy by increasing the particle concentration. We observe samples composed of particles of two sizes, with a size ratio of 1:2.1 and a volume fraction ratio 1:6, using fast laser scanning confocal microscopy... | 18,851,041 |
Kinetic Monte Carlo study on the decay of two-dimensional nanostructures: influence of the activation energy of diffusion on kinetic and morphological properties. | Surface diffusion-mediated decay of two-dimensional nanostructures is studied by means of a kinetic Monte Carlo model. We consider several possible choices for the activation energies associated with possible diffusion paths, including simple phenomenological models, as well as results provided by the embedded atom mod... | 18,851,043 |
Biaxial nematic and smectic phases of parallel particles with different cross sections. | We have calculated the phase diagrams of one-component fluids made of five types of biaxial particles differing in their cross sections. The orientation of the principal particle axis is fixed in space, while the second axis is allowed to freely rotate. We have constructed a free-energy density functional based on fund... | 18,851,053 |
Structural study of coacervation in protein-polyelectrolyte complexes. | Coacervation is a dense liquid-liquid phase separation and herein we report coacervation of protein bovine serum albumin (BSA) in the presence of polyelectrolyte sodium polystyrene sulfonate (NaPSS) under varying solution conditions. Small-angle neutron scattering (SANS) measurements have been performed on above protei... | 18,851,071 |
Swarming in three dimensions. | We consider a three-dimensional model of active Brownian particles interacting via a Morse-type potential. The system exhibits two modes of motion: translation and a coherent rotation in a torus-shape structure. We observe noise-induced transitions in both directions between the two states. These occur at different noi... | 18,851,085 |
Secular series and renormalization group for amplitude equations. | We have developed a technique that circumvents the process of elimination of secular terms [L.-Y. Chen, N. Goldenfeld, and Y. Oono, Phys. Rev. E 54, 376 (1996)] and reproduces the uniformly valid approximations, amplitude equations, and first integrals. The technique is based on a rearrangement of secular terms and the... | 18,851,089 |
Theory of DNA translocation through narrow ion channels and nanopores with charged walls. | Translocation of a single-stranded DNA molecule through genetically engineered alpha -hemolysin channels with positively charged walls is studied. It is predicted that transport properties of such channels are dramatically different from neutral wild-type alpha -hemolysin channels. We assume that the wall charges compe... | 18,851,091 |
Time-resolved spectra of single-bubble sonoluminescence in sulfuric acid with a streak camera. | The time-resolved spectra of single-bubble sonoluminescence (SBSL) in sulfuric acid have been observed with a streak camera after a spectrograph. The spectral center evolves from infrared to ultraviolet gradually within a SBSL duration, which corresponds to an increase of temperature. The peak temperature within one so... | 18,851,095 |
Spectral centrality measures in complex networks. | Complex networks are characterized by heterogeneous distributions of the degree of nodes, which produce a large diversification of the roles of the nodes within the network. Several centrality measures have been introduced to rank nodes based on their topological importance within a graph. Here we review and compare ce... | 18,851,105 |
Static and dry friction due to multiscale surface roughness. | It is shown on the basis of scaling arguments that a disordered interface between two elastic solids will quite generally exhibit static and dry friction (i.e., kinetic friction which does not vanish as the sliding velocity approaches zero) because of Tomlinson-model instabilities that occur for small-length-scale aspe... | 18,851,109 |
Quantum ratchet accelerator without a bichromatic lattice potential. | In a quantum ratchet accelerator system, a linearly increasing directed current can be dynamically generated without using a biased field. Generic quantum ratchet acceleration with full classical chaos [J. B. Gong and P. Brumer, Phys. Rev. Lett. 97, 240602 (2006)] constitutes a new element of quantum chaos and an inter... | 18,851,133 |
Instability of a leaky dielectric coaxial jet in both axial and radial electric fields. | The temporal linear instability of a coaxial jet with two immiscible Newtonian liquids in both the axial and radial electric fields is studied. The outer liquid is supposed to be a leaky dielectric and the inner liquid a perfect dielectric. The eigenvalue problem for both axisymmetric instability and helical instabilit... | 18,851,138 |
Waves on the surface of a vapor film under conditions of intensive heat fluxes. | We investigate surface waves on the interface between a thin vapor film and a layer of liquid in the presence of a high steady heat flux. This problem arises when a metal surface heated to a high temperature is immersed into a cold liquid. The general boundary conditions, which take into account the temperature depende... | 18,851,154 |
Hydrodynamic correlations in the translocation of a biopolymer through a nanopore: theory and multiscale simulations. | We investigate the process of biopolymer translocation through a narrow pore using a multiscale approach which explicitly accounts for the hydrodynamic interactions of the molecule with the surrounding solvent. The simulations confirm that the coupling of the correlated molecular motion to hydrodynamics results in sign... | 18,851,186 |
Controllable scattering of a single photon inside a one-dimensional resonator waveguide. | We analyze the coherent transport of a single photon, which propagates in a one-dimensional coupled-resonator waveguide and is scattered by a controllable two-level system located inside one of the resonators of this waveguide. Our approach, which uses discrete coordinates, unifies low and high energy effective theorie... | 18,851,197 |
Hydrodynamics of nanoscopic capillary waves. | The dynamics of nanoscopic capillary waves on simple liquid surfaces is analyzed using molecular dynamics simulations. Each Fourier mode of the surface is obtained from the molecular positions, and its time behavior compared with the hydrodynamic prediction. We trace the transition from propagating to overdamped modes,... | 18,851,230 |
Dissipation-driven quantum phase transition in superconductor-graphene systems. | We show that a system of Josephson junctions coupled via low-resistance tunneling contacts to graphene substrate(s) may effectively operate as a current switching device. The effect is based on the dissipation-driven superconductor-to-insulator quantum phase transition, which happens due to the interplay of the Josephs... | 18,851,232 |
Influence of the core-valence interaction and of the pseudopotential approximation on the electron self-energy in semiconductors. | State-of-the-art theory addresses single-electron excitations in condensed matter by linking density-functional theory (DFT) with many-body perturbation theory. In actual calculations it is common to employ the pseudopotential (PP) approach, where pseudo-wave-functions enter the calculation of the self-energy, and the ... | 18,851,234 |
Cosmological perturbation theory in slow-roll spacetimes. | We present a gauge-invariant argument that a nonlocal measure of second-order metric and matter perturbations dominates that of linear fluctuations in its effect on the gravitational field in "slow-rolling" spacetimes. | 18,851,270 |
Optical Tamm states in one-dimensional magnetophotonic structures. | We demonstrate the existence of a spectrally narrow localized surface state, the so-called optical Tamm state, at the interface between one-dimensional magnetophotonic and nonmagnetic photonic crystals. The state is spectrally located inside the photonic band gaps of each of the photonic crystals comprising this magnet... | 18,851,281 |
Meandering fluid streams in the presence of flow-rate fluctuations. | We report that meandering of a rivulet flowing down a nonerodible, partially wetting incline is triggered by flow-rate fluctuations and sustained by external noise forcing. In our experiments, the former is provided by an electronically controlled valve, and the latter is due to fluid droplets left on the surface by pr... | 18,851,285 |
Inclusive K(S);(0)K(S);(0) resonance production in ep collisions at HERA. | Inclusive K_{S};{0}K_{S};{0} production in ep collisions at the DESY ep collider HERA was studied with the ZEUS detector using an integrated luminosity of 0.5 fb;{-1}. Enhancements in the mass spectrum were observed and are attributed to the production of f_{2}(1270)/a_{2};{0}(1320), f_{2};{'}(1525) and f_{0}(1710). Ma... | 18,851,276 |
Thickness induced structural changes in polystyrene films. | Changes to the structure of polystyrene melt films as measured through the spectrum of density fluctuations have been observed as a function of film thickness down to the polymer radius of gyration (Rg). Films thicker than 4Rg show bulklike density fluctuations. Thinner films exhibit a peak in S(q) near q=0 which grows... | 18,851,293 |
Multifractality at the quantum Hall transition: beyond the parabolic paradigm. | We present an ultrahigh-precision numerical study of the spectrum of multifractal exponents Deltaq characterizing anomalous scaling of wave function moments |psi|2q at the quantum Hall transition. The result reads Deltaq=2q(1-q)[b0+b1(q-1/2)2+cdots, three dots, centered], with b0=0.1291+/-0.0002 and b1=0.0029+/-0.0003.... | 18,851,310 |
Superconductivity at 22 K in Co-doped BaFe2As2 crystals. | Here we report bulk superconductivity in BaFe1.8Co0.2As2 single crystals below Tc=22 K, as demonstrated by resistivity, magnetic susceptibility, and specific heat data. Hall data indicate that the dominant carriers are electrons, as expected from simple chemical reasoning. This is the first example of superconductivity... | 18,851,319 |
Strain softening in stretched DNA. | The microscopic mechanics of DNA stretching was characterized using extensive molecular dynamics simulations. By employing an anisotropic pressure-control method, realistic force-extension dependences of effectively infinite DNA molecules were obtained. A coexistence of B and S DNA domains was observed during the overs... | 18,851,334 |
Accurate coarse-grained modeling of red blood cells. | We develop a systematic coarse-graining procedure for modeling red blood cells (RBCs) using arguments based on mean-field theory. The three-dimensional RBC membrane model takes into account the bending energy, in-plane shear energy, and constraints of fixed surface area and fixed enclosed volume. The coarse-graining pr... | 18,851,338 |
Single-molecule observation of anomalous electrohydrodynamic orientation of microtubules. | We use fluorescence microscopy to measure the orientation and shape of microtubules-which serve as a model system for semiflexible rods-that are electrophoretically driven. Surprisingly, a bimodal orientation distribution is observed, with microtubules in either parallel or perpendicular orientations to the electric fi... | 18,851,339 |
Statistics of the work done on a quantum critical system by quenching a control parameter. | We study the statistics of the work done on a quantum critical system by quenching a control parameter in the Hamiltonian. We elucidate the relation between the probability distribution of the work and the Loschmidt echo, a quantity emerging usually in the context of dephasing. Using this connection we characterize the... | 18,851,354 |
Production of new heavy isotopes in low-energy multinucleon transfer reactions. | It is shown that the multinucleon transfer reactions in low-energy collisions of heavy ions may be used for production of new neutron-rich nuclei at the "northeast" part of the nuclear map along the neutron closed shell N=126 which plays an important role in the r process of nucleosynthesis. More than 50 unknown nuclei... | 18,851,367 |
Simultaneous spatial and spectral transparency in ultralong fiber lasers. | We demonstrate that ultralong Raman lasers can be used to generate a transmission medium with simultaneous transparency over the spatial and the spectral domains. Numerical calculations show this cross-domain transparency to be preserved when the medium is used for transmitting high-intensity signals, which makes ultra... | 18,851,373 |
Analytical light bullet solutions to the generalized (3+1)-dimensional nonlinear Schrödinger equation. | We obtain exact spatiotemporal periodic traveling wave solutions to the generalized (3+1)-dimensional nonlinear Schrödinger equation with distributed coefficients. We utilize these solutions to construct analytical light bullet soliton solutions of nonlinear optics. | 18,851,374 |
Positron injection and acceleration on the wake driven by an electron beam in a foil-and-gas plasma. | A novel approach for generating and accelerating positron bunches in a plasma wake is proposed and modeled. The system consists of a plasma with an embedded thin foil into which two electron beams are shot. The first beam creates a region for accelerating and focusing positrons and the second beam provides positrons to... | 18,851,378 |
Quantum delocalization of molecular hydrogen in alkali-graphite intercalates. | The adsorption of molecular hydrogen (H2) in the graphite intercalation compound KC24 is studied both experimentally and theoretically. High-resolution inelastic neutron data show spectral features consistent with a strong pinning of H2 along a single axis. First-principles calculations provide novel insight into the n... | 18,851,392 |
Uncompensated moments in the MnPd/Fe exchange bias system. | The element-specific magnetic structure of an epitaxially grown Mn_52Pd_48/Fe bilayer showing exchange bias was investigated with atomic-layer depth sensitivity at the antiferromagnet/ferromagnet interface by soft-x-ray magnetic circular dichroism and magnetic reflectivity. A complex magnetic interfacial configuration,... | 18,851,395 |
Universal critical exponent in class D superconductors. | We study a physical system consisting of noninteracting quasiparticles in disordered superconductors that have neither time-reversal nor spin-rotation invariance. This system belongs to class D within the recent classification scheme of random matrix ensembles, and its phase diagram contains three different phases: met... | 18,851,403 |
One-way quantum computing in the optical frequency comb. | One-way quantum computing allows any quantum algorithm to be implemented easily using just measurements. The difficult part is creating the universal resource, a cluster state, on which the measurements are made. We propose a scalable method that uses a single, multimode optical parametric oscillator (OPO). The method ... | 18,851,426 |
Thermodynamics and bulk viscosity of approximate black hole duals to finite temperature quantum chromodynamics. | We consider classes of translationally invariant black hole solutions whose equations of state closely resemble that of QCD at zero chemical potential. We use these backgrounds to compute the ratio zeta/s of bulk viscosity to entropy density. For a class of black holes that exhibits a first-order transition, we observe... | 18,851,435 |
Nanoscale stratification of local optical fields in low-dimensional atomic lattices. | We predict nanoscale field and dipole patterns due to the broken uniformity of a laser-driven local field in 1D and 2D lattices. They may result in size-related resonances and large field enhancement, which in turn can give rise to low-intensity nonlinear optical effects, e.g., optical bistability, even in the ultimate... | 18,851,449 |
93Nb NMR spin echo spectroscopy in single crystal NbSe3. | We report electric field induced phase displacements of the charge density wave (CDW) in a single crystal of NbSe3 using 93Nb NMR spin-echo spectroscopy. CDW polarizations in the pinned state induced by unipolar and bipolar pulses are linear and reversible up to at least E = (0.96)ET. The polarizations have a broad dis... | 18,851,473 |
Magnetic friction in Ising spin systems. | A new contribution to friction is predicted to occur in systems with magnetic correlations: Tangential relative motion of two Ising spin systems pumps energy into the magnetic degrees of freedom. This leads to a friction force proportional to the area of contact. The velocity and temperature dependence of this force ar... | 18,851,490 |
Stochastic metallic-glass cellular structures exhibiting benchmark strength. | By identifying the key characteristic "structural scales" that dictate the resistance of a porous metallic glass against buckling and fracture, stochastic highly porous metallic-glass structures are designed capable of yielding plastically and inheriting the high plastic yield strength of the amorphous metal. The stren... | 18,851,542 |
Quantum anomalous hall effect in Hg1-yMnyTe quantum wells. | The quantum Hall effect is usually observed when a two-dimensional electron gas is subjected to an external magnetic field, so that their quantum states form Landau levels. In this work we predict that a new phenomenon, the quantum anomalous Hall effect, can be realized in Hg{1-y}Mn{y}Te quantum wells, without an exter... | 18,851,555 |
Spin resonance in three-dimensional superconductors: the case of CeCoIn5. | The recent observation of resonance spin excitation at (1/2, 1/2, 1/2) in the superconducting state of CeCoIn5 [C. Stock, Phys. Rev. Lett. 100, 087001 (2008)10.1103/Phys. Rev. Lett.100.087001] was interpreted as evidence for d{x{2}-y{2}} gap symmetry, by analogy with cuprates. This is true if the resonance is a spin ex... | 18,851,562 |
Determining exchange splitting in a magnetic semiconductor by spin-filter tunneling. | A large exchange splitting of the conduction band in ultrathin films of the ferromagnetic semiconductor EuO was determined quantitatively, by using EuO as a tunnel barrier and fitting the current-voltage characteristics and temperature dependence to tunneling theory. This exchange splitting leads to different tunnel ba... | 18,851,564 |
Counting atoms using interaction blockade in an optical superlattice. | We report on the observation of an interaction blockade effect for ultracold atoms in optical lattices, analogous to the Coulomb blockade observed in mesoscopic solid state systems. When the lattice sites are converted into biased double wells, we detect a discrete set of steps in the well population for increasing bia... | 18,851,591 |
Ab initio many-body calculations of n-3H, n-4He, p-3,4He, and n-10Be scattering. | We develop a new ab initio many-body approach capable of describing simultaneously both bound and scattering states in light nuclei, by combining the resonating-group method with the use of realistic interactions, and a microscopic and consistent description of the nucleon clusters. This approach preserves translationa... | 18,851,604 |
Study of B meson decays with excited eta and eta' mesons. | Using 383 x 10(6) BBover pairs from the BABAR data sample, we report results for branching fractions of six charged B-meson decay modes, where a charged kaon recoils against a charmless resonance decaying to KKover* or etapipi final states with mass in the range (1.2-1.8) GeV/c2. We observe a significant enhancement at... | 18,851,601 |
Defect mediated desorption of the KBr(001) surface induced by single highly charged ion impact. | The individual impacts of slow (300 eV/amu) highly charged Xe ions induce nanometer sized pitlike structures on the KBr (001) surface. The volume of these structures shows a strong dependence on the ions potential energy. Total potential sputter yields from atomically flat (001) terraces are determined by imaging singl... | 18,851,625 |
Time-dependent density-functional theory with a self-interaction correction. | We discuss an implementation of the self-interaction correction for the local-density approximation to time-dependent density-functional theory. A variational formulation is given, taking care of the necessary constraints. A manageable and transparent propagation scheme using two sets of wave functions is proposed and ... | 18,851,631 |
Structural relaxation due to electronic correlations in the paramagnetic insulator KCuF3. | A computational scheme for the investigation of complex materials with strongly interacting electrons is formulated which is able to treat atomic displacements, and hence structural relaxation, caused by electronic correlations. It combines ab initio band structure and dynamical mean-field theory and is implemented in ... | 18,851,632 |
Vanishing hall coefficient in the extreme quantum limit in photocarrier-doped SrTiO3. | We explore the extreme quantum limit of photogenerated electrons in quantum paraelectric SrTiO3. This regime is distinct from conventional semiconductors, due to the large electron effective mass and large dielectric constant. At low temperature, the magnetoresistance and Hall resistivity saturate at a high magnetic fi... | 18,851,634 |
Emergence and visualization of an interface state during contact formation with a single molecule. | Contact formation dynamics and electronic perturbations arising from the interaction of a metallic probe and a single molecule (1,3 cyclohexadiene) bound on the Si (100) surface are examined using a series of plane wave, density functional theory calculations. The approach of the probe induces a relaxation of the molec... | 18,851,635 |
Temperature-dependent transport in suspended graphene. | The resistivity of ultraclean suspended graphene is strongly temperature (T) dependent for 5<T<240 K. At T-5 K transport is near-ballistic in a device of approximately 2 microm dimension and a mobility approximately 170,000 cm2/V s. At large carrier density, n>0.5 x 10(11) cm(-2), the resistivity increases wit... | 18,851,636 |
Detection of coherent magnons via ultrafast pump-probe reflectance spectroscopy in multiferroic Ba0.6Sr1.4Zn2Fe12O22. | We report the detection of a magnetic resonance mode in multiferroic Ba0.6Sr1.4Zn2Fe12O22 using time-domain pump-probe reflectance spectroscopy. Magnetic sublattice precession is coherently excited via picosecond thermal modification of the exchange energy. Importantly, this precession is recorded as a change in reflec... | 18,851,660 |
Ranking vertices or edges of a network by loops: a new approach. | We introduce loop ranking, a new ranking measure based on the detection of closed paths, which can be computed in an efficient way. We analyze it with respect to several ranking measures which have been proposed in the past, and are widely used to capture the relative importance of the vertices in complex networks. We ... | 18,851,664 |
Packed with Salmonella--investigation of an international outbreak of Salmonella Senftenberg infection linked to contamination of prepacked basil in 2007. | Salmonella Senftenberg is uncommon in the United Kingdom. In January-June 2007, the Health Protection Agency reported on 55 primary human cases of Salmonella Senftenberg in England and Wales. In May 2007, fresh basil sold in the United Kingdom was found to be contaminated with Salmonella Senftenberg. We launched an inv... | 18,851,676 |
Antimicrobial activity of commercial citrus-based natural extracts against Escherichia coli O157:H7 isolates and mutant strains. | Due to increasing concerns about the development of antimicrobial resistance amongst pathogenic bacteria, alternative strategies have been sought that do not use antibiotics to reduce pathogenic bacteria from foods and patients. A natural compound that has potent antimicrobial properties is citrus peel, which contains ... | 18,851,678 |
Identification of a possible ancestor of the subtype A1 HIV Type 1 variant circulating in the former Soviet Union. | The HIV-1 subsubtype A1 epidemic of the former Soviet Union (FSU) was caused by an A1 variant apparently derived from a single introduction event. We identified an A1 variant highly related to the A1 lineage circulating in the FSU in a patient from Conakry, Republic of Guinea, who was diagnosed with HIV-1 when he moved... | 18,851,681 |
The cannabinoid CB1 receptor and the endocannabinoid anandamide: possible antidepressant targets. | Major depression has the highest rate of prevalence and incidence of morbidity among all mental disoders. The limited efficacies of current antidepressant treatments necessitate the development of alternative pharmacotherapies. Recent preclinical findings suggesting that cannabinoid CB(1) receptor agonists and endocann... | 18,851,692 |
Challenges in developing targeted therapy for pancreatic adenocarcinoma. | Pancreatic adenocarcinoma is a leading cause of cancer deaths in the US. Gemcitabine-based chemotherapy remains the cornerstone treatment for advanced pancreatic cancers. Research into the molecular pathogenesis of pancreatic cancers has allowed scientists to understand the complex heterogeneous signals associated with... | 18,851,695 |
The COXIB experience: a look in the rearview mirror. | Non-steroidal anti-inflammatory drugs (NSAIDs) are among the most widely used prescription and nonprescription drugs in the world. The discovery of cyclooxygenase (COX) as the target of NSAIDs, the subsequent identification of two isoforms of COX (COX-1 and COX-2), and studies of their regulation and sites of expressio... | 18,851,701 |
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