Theory of electric-field-induced metal-insulator transition in doped manganites

The insulator to metal transition (IMT) induced by the application of an electric field in doped manganites is investigated theoretically. Starting from the double-exchange mechanism with the long-range Coulomb interaction included, we find that the electric field may suppress the charge ordering and drive the system from the antiferromagnetic and charge-ordered state with an energy gap at the Fermi level to the ferromagnetic and gapless state, resulting in the IMT. A numerical simulation is performed for manganite films with intrinsic inhomogeneities, and an important impact of the inhomogeneities on this electric-field-induced transition is obtained. Our results can naturally account for the recently observed electric-filed-induced IMT phenomenon in manganites.published_or_final_versio

Vortex charges in high-temperature superconductors

The vortex charge in high-temperature superconductors was investigated. It was found that the vortex charge was negative when a sufficient strength of antiferromagnetic (AF) order was induced inside the vortex core. The vortex charge at optimal doping was studied as a function of magnetic field. The results showed that the AF order was absent inside the vortex core for small Coulomb repulsion.published_or_final_versio

Ginzburg-Landau equations for layered p-wave superconductors

Based on Gor'kov's theory of weakly coupled superconductors, the Ginzburg-Landau equations for layered p-wave superconductors are derived, the order parameter of which is assumed to belong to a nontrivial two-dimensional representation. This calculation allows us to microscopically determine the expansion coefficients of the Ginzburg-Landau free-energy functional with respect to the order parameter. The main feature of the vortex solution is briefly discussed. It is found that the extreme condition for the nonaxisymmetric singly quantized vortices is not ensured in the weak-coupling limit. If the discrete crystal symmetry is included, the axisymmetric singly quantized vortex is stable. In addition, the upper critical field is also solely determined within the weak-coupling framework.published_or_final_versio

Enhanced superconducting proximity effect in strongly correlated heterostructures

The electronic properties of a strongly correlated heterostructure consisting of t-J layer and metallic layer have been investigated by using the Gutzwiller projected mean-field approximation. Considering the proximity effect due to the large pseudogap energy scale of t-J layer, a large superconducting gap could be induced on the metallic layer. This enhanced superconducting gap may be even larger than that of the t-J layer. Related physical quantities including spectral functions and density of states are obtained. The consequences of these results on experiments are discussed. © 2010 The American Physical Society.published_or_final_versio

Out-Of-Plane Transverse Resistivity in High-T-C Superconductors as a Signature of Flow of Rigid Vortex Lines

Journals published by the American Physical Society can be found at http://journals.aps.org/When the transport current is applied parallel to the CuO2 layers, say, along the a axis, of a high-T-c superconductor, and the magnetic field B is in a direction which makes a polar angle theta with the c axis and an azimuthal angle phi with the ac plane, for the case of rigid flux lines, in addition to the usual longitudinal resistivity rho(perpendicular to), there should also exist an out-of-plane transverse resistivity rho(perpendicular to), which is of the same order of magnitude as rho(perpendicular to) and satisfies the relation rho(perpendicular to)/rho(parallel to) =tan theta cos phi in the high anisotropy limit and for theta being not very close to pi/2. For less rigid flux lines, reduction in rho(perpendicular to)rho(parallel to) from this prediction should be observed, and for a set of decoupled pancake vortices, rho(perpendicular to) should vanish entirely

Consistency between the Lorentz-Force Independence of the Resistive Transition in the High-T-C Superconductors and the Standard Theory of Flux-Flow

Journals published by the American Physical Society can be found at http://journals.aps.org

Quasiparticle resonant states induced by a unitary impurity in a d-wave superconductor

Journals published by the American Physical Society can be found at http://journals.aps.org/The quasiparticle resonant states around a single nonmagnetic impurity with unitary scattering in a d-wave superconductor is studied by solving the Bogoliubov-de Gennes equations based on a t-J model. Both the spatial variation of the order parameter and the local density of states (LDOS) around the impurity have been investigated. We find that (i) a particle-hole symmetric system has a single symmetric zero-energy peak in the LDOS regardless of the size of the superconducting coherence length xi(0); (ii) for the particle-hole asymmetric case, an asymmetric splitting of the zero-energy peak is intrinsic to a system with a small value of k(F)xi(0)

Efficient Surveillance of Plasmodium knowlesi Genetic Subpopulations, Malaysian Borneo, 2000-2018.

Population genetic analysis revealed that Plasmodium knowlesi infections in Malaysian Borneo are caused by 2 divergent parasites associated with long-tailed (cluster 1) and pig-tailed (cluster 2) macaques. Because the transmission ecology is likely to differ for each macaque species, we developed a simple genotyping PCR to efficiently distinguish between and survey the 2 parasite subpopulations. This assay confirmed differences in the relative proportions in areas of Kapit division of Sarawak state, consistent with multilocus microsatellite analyses. Analyses of 1,204 human infections at Kapit Hospital showed that cluster 1 caused approximately two thirds of cases with no significant temporal changes from 2000 to 2018. We observed an apparent increase in overall numbers in the most recent 2 years studied, driven mainly by increased cluster 1 parasite infections. Continued monitoring of the frequency of different parasite subpopulations and correlation with environmental alterations are necessary to determine whether the epidemiology will change substantially

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

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