2,490 research outputs found

    Completely assembled virus particles detected by transmission electron microscopy in proximal and mid-axons of neurons infected with herpes simplex virus type 1, herpes simplex virus type 2 and pseudorabies virus

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    The morphology of alphaherpesviruses during anterograde axonal transport from the neuron cell body towards the axon terminus is controversial. Reports suggest that transport of herpes simplex virus type 1 (HSV-1) nucleocapsids and envelope proteins occurs in separate compartments and that complete virions form at varicosities or axon termini (subassembly transport model), while transport of a related alphaherpesvirus, pseudorabies virus (PRV) occurs as enveloped capsids in vesicles (assembled transport model). Transmission electron microscopy of proximal and mid-axons of primary superior cervical ganglion (SCG) neurons was used to compare anterograde axonal transport of HSV-1, HSV-2 and PRV. SCG cell bodies were infected with HSV-1 NS and 17, HSV-2 2.12 and PRV Becker. Fully assembled virus particles were detected intracellularly within vesicles in proximal and mid-axons adjacent to microtubules after infection with each virus, indicating that assembled virions are transported anterograde within axons for all three alphaherpesviruses

    Universal quantum interfaces

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    To observe or control a quantum system, one must interact with it via an interface. This letter exhibits simple universal quantum interfaces--quantum input/output ports consisting of a single two-state system or quantum bit that interacts with the system to be observed or controlled. It is shown that under very general conditions the ability to observe and control the quantum bit on its own implies the ability to observe and control the system itself. The interface can also be used as a quantum communication channel, and multiple quantum systems can be connected by interfaces to become an efficient universal quantum computer. Experimental realizations are proposed, and implications for controllability, observability, and quantum information processing are explored.Comment: 4 pages, 3 figures, RevTe

    Solutions of a certain class of fractional differintegral equations

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    AbstractRecently, several authors demonstrated the usefulness of fractional calculus in obtaining particular solutions of a number of such familiar second-order differential equations as those associated with Gauss, Legendre, Jacobi, Chebyshev, Coulomb, Whittaker, Euler, Hermite, and Weber equations. The main object of this paper is to show how some of the latest contributions on the subject by Tu et al. [1], involving the associated Legendre, Euler, and Hermite equations, can be presented in a unified manner by suitably appealing to a general theorem on particular solutions of a certain class of fractional differintegral equations

    A New Approach to Analytic, Non-Perturbative and Gauge-Invariant QCD

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    Following a previous calculation of quark scattering in eikonal approximation, this paper presents a new, analytic and rigorous approach to the calculation of QCD phenomena. In this formulation a basic distinction between the conventional "idealistic" description of QCD and a more "realistic" description is brought into focus by a non-perturbative, gauge-invariant evaluation of the Schwinger solution for the QCD generating functional in terms of the exact Fradkin representations of the Green's functional and the vacuum functional. Because quarks exist asymptotically only in bound states, their transverse coordinates can never be measured with arbitrary precision; the non-perturbative neglect of this statement leads to obstructions that are easily corrected by invoking in the basic Lagrangian a probability amplitude which describes such transverse imprecision. The second result of this non-perturbative analysis is the appearance of a new and simplifying output called "Effective Locality", in which the interactions between quarks by the exchange of a "gluon bundle" - which "bundle" contains an infinite number of gluons, including cubic and quartic gluon interactions - display an exact locality property that reduces the several functional integrals of the formulation down to a set of ordinary integrals. It should be emphasized that "non-perturbative" here refers to the effective summation of all gluons between a pair of quark lines, but does not (yet) include a summation over all closed-quark loops which are tied by gluon-bundle exchange to the rest of the "Bundle Diagram". As an example of the power of these methods we offer as a first analytic calculation the quark-antiquark binding potential of a pion, and the corresponding three-quark binding potential of a nucleon, obtained in a simple way from relevant eikonal scattering approximations.Comment: 38 pages, 3 figures in REVTeX. Collections of follow-on work of Eur. Phys. J. C65, pp. 395-411 (2010). arXiv admin note: text overlap with arXiv:1103.4179, arXiv:1104.4663, arXiv:1003.293

    Transient Analysis of Lossy Transmission Lines: an Efficient Approach Based on the Method of Characteristics

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    This paper is devoted to transient analysis of lossy transmission lines characterized by frequency-dependent parameters. A public dataset of parameters for three line examples (a module, a board, and a cable) is used, and a new example of on-chip interconnect is introduced. This dataset provides a well established and realistic benchmark for accuracy and timing analysis of interconnect analysis tools. Particular attention is devoted to the intrinsic consistency and causality of these parameters. Several implementations based on generalizations of the well-known method-of-characteristics are presented. The key feature of such techniques is the extraction of the line modal delays. Therefore, the method is highly optimized for long interconnects characterized by significant propagation delay. Nonetheless, the method is also successfully applied here to a short high/loss on-chip line, for which other approaches based on lumped matrix rational approximations can also be used with high efficiency. This paper shows that the efficiency of delay extraction techniques is strongly dependent on the particular circuit implementation and several practical issues including generation of rational approximations and time step control are discussed in detail

    B→KB\to K Transition Form Factor up to O(1/mb2){\cal O}(1/m^2_b) within the kTk_T Factorization Approach

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    In the paper, we apply the kTk_T factorization approach to deal with the B→KB\to K transition form factor F+,0B→K(q2)F^{B\to K}_{+,0}(q^2) in the large recoil regions. The B-meson wave functions ΨB\Psi_B and ΨˉB\bar\Psi_B that include the three-particle Fock states' contributions are adopted to give a consistent PQCD analysis of the form factor up to O(1/mb2){\cal O} (1/m^2_b). It has been found that both the wave functions ΨB\Psi_B and ΨˉB\bar\Psi_B can give sizable contributions to the form factor and should be kept for a better understanding of the BB meson decays. Then the contributions from different twist structures of the kaon wavefunction are discussed, including the SUf(3)SU_f(3)-breaking effects. A sizable contribution from the twist-3 wave function Ψp\Psi_p is found, whose model dependence is discussed by taking two group of parameters that are determined by different distribution amplitude moments obtained in the literature. It is also shown that F+,0B→K(0)=0.30±0.04F^{B\to K}_{+,0}(0)=0.30\pm0.04 and [F+,0B→K(0)/F+,0B→π(0)]=1.13±0.02[F^{B\to K}_{+,0}(0)/F^{B\to \pi}_{+,0}(0)]=1.13\pm0.02, which are more reasonable and consistent with the light-cone sum rule results in the large recoil regions.Comment: 22 pages and 6 figure

    An interleaved sampling scheme for the characterization of single qubit dynamics

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    In this paper, we demonstrate that interleaved sampling techniques can be used to characterize the Hamiltonian of a qubit and its environmental decoherence rate. The technique offers a significant advantage in terms of the number of measurements that are required to characterize a qubit. When compared to the standard Nyquist-Shannon sampling rate, the saving in the total measurement time for the interleaved method is approximately proportional to the ratio of the sample rates.Comment: 9 pages, 4 figure

    Study of the Anti-Proliferative Activity of 5-Substituted 4,7-Dimethoxy-1,3-Benzodioxole Derivatives of SY-1 from Antrodia camphorata on Human COLO 205 Colon Cancer Cells

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    A set of 10 4,7-dimethoxy-1,3-benzodioxole derivatives based on a lead compound previously discovered by our group, SY-1, which was isolated from Antrodia camphorata, were evaluated for their in vitro inhibitory activity on human colorectal carcinoma cells (COLO 205). Structure-activity relationship studies of the 10 compounds indicated the importance of the chain length of the alkyl group at the 5-position, and the 2-propenyl substituent named “apiole” exhibited the most potent inhibitory activity. In the present study, we demonstrate that the SY-1 analogue “apiole” decreased the proliferation of COLO 205 cells, but not that of normal human colonic epithelial cells (FHC). The G0/G1 cell cycle arrest induced by apiole (75–225 μM) was associated with significantly increased levels of p53, p21 and p27 and decreased levels of cyclin D1. Concerning COLO 205 cell apoptosis, apiole (>150 μM) treatment significantly increased the levels of cleaved caspases 3, 8, 9 and bax/bcl-2 ratio and induced ladder formation in DNA fragmentation assay and sub-G1 peak in flow cytometry analysis. These findings suggest that apiole can suppress COLO 205 cell growth; however, the detailed mechanisms of these processes require further investigation
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