The relation between cardiac 123I-mIBG scintigraphy and functional response 1 year after CRT implantation

Cardiac resynchronization therapy (CRT) is a disease-modifying therapy in patients with chronic heart failure (CHF). Current guidelines ascribe CRT eligibility on three parameters only: left ventricular ejection fraction (LVEF), QRS duration, and New York Heart Association (NYHA) functional class. However, one-third of CHF patients does not benefit from CRT. This study evaluated whether 123I-meta-iodobenzylguanidine (123I-mIBG) assessed cardiac sympathetic activity could optimize CRT patient selection

Gaussian noise and time-reversal symmetry in non-equilibrium Langevin models

We show that in driven systems the Gaussian nature of the fluctuating force and time-reversibility are equivalent properties. This result together with the potential condition of the external force drastically restricts the form of the probability distribution function, which can be shown to satisfy time-independent relations. We have corroborated this feature by explicitly analyzing a model for the stretching of a polymer and a model for a suspension of non-interacting Brownian particles in steady flow.Comment: 6 pages, submitted to PR

Metal-catalyst-free growth of carbon nanotubes and their application in field-effect transistors

The metal-catalyst-free growth of carbon nanotubes (CNTs) using chemical vapor deposition and the application in field-effect transistors (FETs) is demonstrated. The CNT growth process used a 3-nm-thick Ge layer on SiO2 that was subsequently annealed to produce Ge nanoparticles. Raman measurements show the presence of radial breathing mode peaks and the absence of the disorder induced D-band, indicating single walled CNTs with a low defect density. The synthesized CNTs are used to fabricate CNTFETs and the best device has a state-of-the-art on/off current ratio of 3×108 and a steep sub-threshold slope of 110 mV/dec

Fluctuation theorem for stochastic dynamics

The fluctuation theorem of Gallavotti and Cohen holds for finite systems undergoing Langevin dynamics. In such a context all non-trivial ergodic theory issues are by-passed, and the theorem takes a particularly simple form. As a particular case, we obtain a nonlinear fluctuation-dissipation theorem valid for equilibrium systems perturbed by arbitrarily strong fields.Comment: 15 pages, a section rewritte

Momentum of an electromagnetic wave in dielectric media

Almost a hundred years ago, two different expressions were proposed for the energy--momentum tensor of an electromagnetic wave in a dielectric. Minkowski's tensor predicted an increase in the linear momentum of the wave on entering a dielectric medium, whereas Abraham's tensor predicted its decrease. Theoretical arguments were advanced in favour of both sides, and experiments proved incapable of distinguishing between the two. Yet more forms were proposed, each with their advocates who considered the form that they were proposing to be the one true tensor. This paper reviews the debate and its eventual conclusion: that no electromagnetic wave energy--momentum tensor is complete on its own. When the appropriate accompanying energy--momentum tensor for the material medium is also considered, experimental predictions of all the various proposed tensors will always be the same, and the preferred form is therefore effectively a matter of personal choice.Comment: 23 pages, 3 figures, RevTeX 4. Removed erroneous factor of mu/mu_0 from Eq.(44

Identification of the active site residues in the nsP2 proteinase of sindbis virus

The nonstructural polyproteins of Sindbis virus are processed by a virus-encoded proteinase which is located in the C-terminal domain of nsP2. Here we have performed a mutagenic analysis to identify the active site residues of this proteinase. Substitution of other amino acids for either Cys-481 or His-558 completely abolished proteolytic processing of Sindbis virus polyproteins in vitro. Substitutions within this domain for a second cysteine conserved among alphaviruses, for four other conserved histidines, or for a conserved serine did not affect the activity of the enzyme. These results suggest that nsP2 is a papain-like proteinase whose catalytic dyad is composed of Cys-481 and His-558. Since an asparagine residue has been implicated in the active site of papain, we changed the four conserved asparagine residues in the C-terminal half of nsP2 and found that all could be substituted without total loss of activity. Among papain-like proteinases, the residue following the catalytic histidine is alanine or glycine in the plant and animal enzymes, and the presence of Trp-559 in alphaviruses is unusual. A mutant enzyme containing Ala-559 was completely inactive, implying that Trp-559 is essential for a functional proteinase. All of these mutations were introduced into a full-length clone of Sindbis virus from which infectious RNA could be transcribed in vitro, and the effects of these changes on viability were tested. In all cases it was found that mutations which abolished proteolytic activity were lethal, whether or not these mutations were in the catalytic residues, indicating that proteolysis of the nonstructural polyprotein is essential for Sindbis replication

Transport properties of highly asymmetric hard-sphere mixtures

The static and dynamic properties of binary mixtures of hard spheres with a diameter ratio of sigma(B)/sigma(A)= 0.1 and a mass ratio of m(B)/m(A)= 0.001 are investigated using event driven molecular dynamics. The contact values of the pair correlation functions are found to compare favorably with recently proposed theoretical expressions. The transport coefficients of the mixture, determined from simulation, are compared to the predictions of the revised Enskog theory using both a third-order Sonine expansion and direct simulation Monte Carlo. Overall, the Enskog theory provides a fairly good description of the simulation data, with the exception of systems at the smallest mole fraction of larger spheres (x(A)=0.01) examined. A "fines effect" was observed at higher packing fractions, where adding smaller spheres to a system of large spheres decreases the viscosity of the mixture; this effect is not captured by the Enskog theory

Poisson-Bracket Approach to the Dynamics of Nematic Liquid Crystals. The Role of Spin Angular Momentum

Nematic liquid crystals are well modeled as a fluid of rigid rods. Starting from this model, we use a Poisson-bracket formalism to derive the equations governing the dynamics of nematic liquid crystals. We treat the spin angular momentum density arising from the rotation of constituent molecules about their centers of mass as an independent field and derive equations for it, the mass density, the momentum density, and the nematic director. Our equations reduce to the original Leslie-Ericksen equations, including the inertial director term that is neglected in the hydrodynamic limit, only when the moment of inertia for angular momentum parallel to the director vanishes and when a dissipative coefficient favoring locking of the angular frequencies of director rotation and spin angular momentum diverges. Our equations reduce to the equations of nematohydrodynamics in the hydrodynamic limit but with dissipative coefficients that depend on the coefficient that must diverge to produce the Leslie-Ericksen equations.Comment: 10 pages, to be published in Phys. Rev. E 72(5

Heat exchange between two interacting nanoparticles beyond the fluctuation-dissipation regime

We show that the observed non-monotonic behavior of the thermal conductance between two nanoparticles when they are brought into contact is originated by an intricate phase space dynamics. Here it is assumed that this dynamics results from the thermally activated jumping through a rough energy landscape. A hierarchy of relaxation times plays the key role in the description of this complex phase space behaviour. Our theory enables us to analyze the heat transfer just before and at the moment of contact.Comment: 4 pages, 1 figure, approved for publication in Physical Review Letter

The thermodynamic dual structure of linear-dissipative driven systems

The spontaneous emergence of dynamical order, such as persistent currents, is sometimes argued to require principles beyond the entropy maximization of the second law of thermodynamics. I show that, for linear dissipation in the Onsager regime, current formation can be driven by exactly the Jaynesian principle of entropy maximization, suitably formulated for extended systems and nonequilibrium boundary conditions. The Legendre dual structure of equilibrium thermodynamics is also preserved, though it requires the admission of current-valued state variables, and their correct incorporation in the entropy