1,506 research outputs found

    Primordial Neutrinos, Cosmological Perturbations in Interacting Dark-Energy Model: CMB and LSS

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    We present cosmological perturbation theory in neutrinos probe interacting dark-energy models, and calculate cosmic microwave background anisotropies and matter power spectrum. In these models, the evolution of the mass of neutrinos is determined by the quintessence scalar field, which is responsible for the cosmic acceleration today. We consider several types of scalar field potentials and put constraints on the coupling parameter between neutrinos and dark energy. Assuming the flatness of the universe, the constraint we can derive from the current observation is mν<0.87eV\sum m_{\nu} < 0.87 eV at the 95 % confidence level for the sum over three species of neutrinos. We also discuss on the stability issue of the our model and on the impact of the scattering term in Boltzmann equation from the mass-varying neutrinos.Comment: 26 pages Revtex, 11 figures, Add new contents and reference

    Eugenol inhibits sodium currents in dental afferent neurons.

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    Although eugenol is widely used in dentistry, little is known about the molecular mechanisms responsible for its anesthetic properties. In addition to calcium channels, recently demonstrated by our group, there could be another molecular target for eugenol. Using a whole-cell patch-clamp technique, we investigated the effect of eugenol on voltage-gated sodium channel currents (I^sub Na^) in rat dental primary afferent neurons identified by retrograde labeling with a fluorescent dye in maxillary molars. Eugenol inhibited action potentials and I^sub Na^ in both capsaicin-sensitive and capsaicin-insensitive neurons. The pre-treatment with capsazepine, a competitive antagonist of transient receptor potential vanilloid 1 (TRPV1), failed to block the inhibitory effect of eugenol on I^sub Na^, suggesting no involvement of TRPV1. Two types of I^sub Na^, tetrodotoxin (TTX)-resistant and TTX-sensitive I^sub Na^, were inhibited by eugenol. Our results demonstrated that eugenol inhibits I^sub Na^ in a TRPV1-independent manner. We suggest that I^sub Na^ inhibition by eugenol contributes to its analgesic effect

    STK295900, a Dual Inhibitor of Topoisomerase 1 and 2, Induces G<inf>2</inf> Arrest in the Absence of DNA Damage

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    STK295900, a small synthetic molecule belonging to a class of symmetric bibenzimidazoles, exhibits antiproliferative activity against various human cancer cell lines from different origins. Examining the effect of STK295900 in HeLa cells indicates that it induces G2 phase arrest without invoking DNA damage. Further analysis shows that STK295900 inhibits DNA relaxation that is mediated by topoisomerase 1 (Top 1) and topoisomerase 2 (Top 2) in vitro. In addition, STK295900 also exhibits protective effect against DNA damage induced by camptothecin. However, STK295900 does not affect etoposide-induced DNA damage. Moreover, STK295900 preferentially exerts cytotoxic effect on cancer cell lines while camptothecin, etoposide, and Hoechst 33342 affected both cancer and normal cells. Therefore, STK295900 has a potential to be developed as an anticancer chemotherapeutic agent. © 2013 Kim et al

    Density of states, Potts zeros, and Fisher zeros of the Q-state Potts model for continuous Q

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    The Q-state Potts model can be extended to noninteger and even complex Q in the FK representation. In the FK representation the partition function,Z(Q,a), is a polynomial in Q and v=a-1(a=e^-T) and the coefficients of this polynomial,Phi(b,c), are the number of graphs on the lattice consisting of b bonds and c connected clusters. We introduce the random-cluster transfer matrix to compute Phi exactly on finite square lattices. Given the FK representation of the partition function we begin by studying the critical Potts model Z_{CP}=Z(Q,a_c), where a_c=1+sqrt{Q}. We find a set of zeros in the complex w=sqrt{Q} plane that map to the Beraha numbers for real positive Q. We also identify tilde{Q}_c(L), the value of Q for a lattice of width L above which the locus of zeros in the complex p=v/sqrt{Q} plane lies on the unit circle. We find that 1/tilde{Q}_c->0 as 1/L->0. We then study zeros of the AF Potts model in the complex Q plane and determine Q_c(a), the largest value of Q for a fixed value of a below which there is AF order. We find excellent agreement with Q_c=(1-a)(a+3). We also investigate the locus of zeros of the FM Potts model in the complex Q plane and confirm that Q_c=(a-1)^2. We show that the edge singularity in the complex Q plane approaches Q_c as Q_c(L)~Q_c+AL^-y_q, and determine the scaling exponent y_q. Finally, by finite size scaling of the Fisher zeros near the AF critical point we determine the thermal exponent y_t as a function of Q in the range 2<Q<3. We find that y_t is a smooth function of Q and is well fit by y_t=(1+Au+Bu^2)/(C+Du) where u=u(Q). For Q=3 we find y_t~0.6; however if we include lattices up to L=12 we find y_t~0.50.Comment: to appear in Physical Review

    Quantum Integrals of Motion for Variable Quadratic Hamiltonians

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    We construct the integrals of motion for several models of the quantum damped oscillators in nonrelativistic quantum mechanics in a framework of a general approach to the time-dependent Schroedinger equation with variable quadratic Hamiltonians. An extension of Lewis-Riesenfeld dynamical invariant is given. The time-evolution of the expectation values of the energy related positive operators is determined for the oscillators under consideration. A proof of uniqueness of the corresponding Cauchy initial value problem is discussed as an application.Comment: 32 pages, no figure

    Fabrication of Functionalized Double-Lamellar Multifunctional Envelope-Type Nanodevices Using a Microfluidic Chip with a Chaotic Mixer Array

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    Multifunctional envelope-type nanodevices (MENDs) are very promising non-viral gene delivery vectors because they are biocompatible and enable programmed packaging of various functional elements into an individual nanostructured liposome. Conventionally MENDs have been fabricated by complicated, labor-intensive, time-consuming bulk batch methods. To avoid these problems in MEND fabrication, we adopted a microfluidic chip with a chaotic mixer array on the floor of its reaction channel. The array was composed of 69 cycles of the staggered chaotic mixer with bas-relief structures. Although the reaction channel had very large Péclet numbers (>105) favorable for laminar flows, its chaotic mixer array led to very small mixing lengths (<1.5 cm) and that allowed homogeneous mixing of MEND precursors in a short time. Using the microfluidic chip, we fabricated a double-lamellar MEND (D-MEND) composed of a condensed plasmid DNA core and a lipid bilayer membrane envelope as well as the D-MEND modified with trans-membrane peptide octaarginine. Our lab-on-a-chip approach was much simpler, faster, and more convenient for fabricating the MENDs, as compared with the conventional bulk batch approaches. Further, the physical properties of the on-chip-fabricated MENDs were comparable to or better than those of the bulk batch-fabricated MENDs. Our fabrication strategy using microfluidic chips with short mixing length reaction channels may provide practical ways for constructing more elegant liposome-based non-viral vectors that can effectively penetrate all membranes in cells and lead to high gene transfection efficiency

    Fisher zeros of the Q-state Potts model in the complex temperature plane for nonzero external magnetic field

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    The microcanonical transfer matrix is used to study the distribution of the Fisher zeros of the Q>2Q>2 Potts models in the complex temperature plane with nonzero external magnetic field HqH_q. Unlike the Ising model for Hq0H_q\ne0 which has only a non-physical critical point (the Fisher edge singularity), the Q>2Q>2 Potts models have physical critical points for Hq<0H_q<0 as well as the Fisher edge singularities for Hq>0H_q>0. For Hq<0H_q<0 the cross-over of the Fisher zeros of the QQ-state Potts model into those of the (Q1Q-1)-state Potts model is discussed, and the critical line of the three-state Potts ferromagnet is determined. For Hq>0H_q>0 we investigate the edge singularity for finite lattices and compare our results with high-field, low-temperature series expansion of Enting. For 3Q63\le Q\le6 we find that the specific heat, magnetization, susceptibility, and the density of zeros diverge at the Fisher edge singularity with exponents αe\alpha_e, βe\beta_e, and γe\gamma_e which satisfy the scaling law αe+2βe+γe=2\alpha_e+2\beta_e+\gamma_e=2.Comment: 24 pages, 7 figures, RevTeX, submitted to Physical Review
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