Charge-orbital density wave and superconductivity in the strong spin-orbit coupled IrTe2:Pd

Using transmission electron microscopy, the anomalies in resistivity and magnetic susceptibility at ~262 K in IrTe2 are found to accompany the superlattice peaks with q[over q=(1/5,0,-1/5). The wave vector is consistent with our theoretical calculation for the Fermi surface nesting vector, indicating that the ~262 K transition is of the charge-orbital density wave (DW) type. We also discovered that both Pd intercalation and substitution induce bulk superconductivity with T(c) up to ~3 K, which competes with DW in a quantum critical pointlike manner.     

Spin waves and revised crystal structure of honeycomb iridate Na2IrO3

We report inelastic neutron scattering measurements on Na2IrO3, a candidate for the Kitaev spin model on the honeycomb lattice. We observe spin-wave excitations below 5 meV with a dispersion that can be accounted for by including substantial further-neighbor exchanges that stabilize zigzag magnetic order. The onset of long-range magnetic order below T(N)=15.3 K is confirmed via the observation of oscillations in zero-field muon-spin rotation experiments. Combining single-crystal diffraction and density functional calculations we propose a revised crystal structure model with significant departures from the ideal 90° Ir-O-Ir bonds required for dominant Kitaev exchange.     

Extracting the near surface stoichiometry of BiFe0.5Mn0.5O3 thin films; a finite element maximum entropy approach

The surface and near-surface chemical composition of BiFe_0.5Mn_0.5O₃ has been studied using a combination of low photon energy synchrotron photoemission spectroscopy, and a newly developed maximum entropy finite element model from which it is possible to extract the depth dependent chemical composition. In the uppermost few unit cells, an overabundance of Bi, and a deficiency of Fe and Mn are observed. In deeper layers, the measurements are consistent with bulk-like stoichiometry.Additionally, a definitive identification of all the observed species together with their abundance and depth dependence is given, and the mixed Fe and Mn valencies are estimated. In addition to the expected bulk valencies Mn^3 + and Fe^3 +, some Fe^2 + and a small amount of Mn^4 + are also observed. The maximum entropy finite element model demonstrated here is also discussed in more general terms and its potential application to the broader field of perovskite thin films is made apparent.     

Demonstration of a state-insensitive, compensated nanofiber trap

We report the experimental realization of an optical trap that localizes single Cs atoms ?215 nm from the surface of a dielectric nanofiber. By operating at magic wavelengths for pairs of counterpropagating red- and blue-detuned trapping beams, differential scalar light shifts are eliminated, and vector shifts are suppressed by ≈250. We thereby measure an absorption linewidth Γ/2π=5.7±0.1 MHz for the Cs 6S_{1/2}, F=4→6P_{3/2}, F^{'}=5 transition, where Γ_{0}/2π=5.2 MHz in free space. An optical depth d?66 is observed, corresponding to an optical depth per atom d_{1}?0.08. These advances provide an important capability for the implementation of functional quantum optical networks and precision atomic spectroscopy near dielectric surfaces.     

Single-mode whispering gallery lasing from metal-clad GaN nanopillars

An ordered hexagonal closed-packed nanopillar array is fabricated on GaN. A metal coating is then applied to encapsulate the pillars for promoting optical confinement within the cylindrical cavity. Room-temperature lasing at 373 nm is observed under pulsed excitation, at a lasing threshold of 0.42 MW/cm2. With pillar diameters of around 980 nm, the number of modes overlapping the emission spectrum is reduced, giving rise to single-mode whispering gallery stimulated emission. Finite-difference time-domain simulations are carried out for the prediction of resonant frequencies and electric field patterns corresponding to the resonant modes.     

Light-Front Zero-Mode Issue for the Transition Form Factors Between Pseudoscalar and Vector Mesons

We study the light-front zero-mode contribution to the transition form factors (g, f, a _±, T _i ) (i = 1, 2, 3) for the exclusive semileptonic P → V ?ν _? and rare P → V ? ⁺?^? decays using a covariant fermion field theory model in (3+1) dimensions. While the zero-mode contribution in principle depends on the form of the vector meson vertex Γ ^μ  = γ ^μ ? (2k ? P _V ) ^μ /D, the six form factors (g, f, a ₊, T ₁, T ₂, T ₃) are found to be free from the zero mode if the denominator D contains the term proportional to the light-front longitudinal momentum fraction factor (1/x) ⁿ of the struck quark with the power n > 0. Although the form factor a _? is not free from the zero mode, the zero-mode contribution comes only either from the simple vertex Γ ^μ  = γ ^μ term or from the other term just with a constant D (i.e. n = 0). We identify the zero-mode operator that is convoluted with the initial- and final-state valence wave functions to generate the zero-mode contribution to a _?.     

An analysis on the Frequency-dependent grounding impedance based on the ground current dissipation of counterpoises in the two-layered soils

Because of the increased usage of power conversion equipment and their susceptibility to lightning strikes, high frequency fault currents flowing through grounding systems are increased. As grounding systems change from individual groundings to common or integrated groundings, the improved performance of grounding systems against high frequency fault currents is urgently required. When regarding the common or integrated grounding systems, most of them are required to satisfy the ground resistance defined by standards or regulations. The grounding system performance against high frequency fault currents is defined by the grounding impedance. A number of studies have reported that grounding system performance is reduced due to the increase of the grounding impedance with increasing of the frequency of fault currents. In this paper, in order to investigate the characteristics of the frequency-dependent grounding impedances of counterpoises installed in the two-layered soils, the ground current dissipation rates in each 10 m section of the counterpoises were measured and analyzed as functions of the length of grounding electrodes and the current injection point. As a result, most of the ground currents above the frequency of 100 kHz are dissipated into the earth near the current injection point and the high frequency grounding impedance of long counterpoises is converged into that of short counterpoises. The high frequency grounding impedance measured at the low soil-resistivity end of the counterpoise buried in the two-layered soils is much lower than that measured at the high soil-resistivity end.     

Synergy between adiponectin and interleukin-1β on the expression of interleukin-6, interleukin-8, and cyclooxygenase-2 in fibroblast-like synoviocytes

To determine whether adiponectin may have synergistic effects in combination with the proinflammatory cytokine interleukin (IL)-1β regarding the production of proinflammatory mediators during arthritic joint inflammation, synovial cells from rheumatoid arthritis (RA) patients were treated with adiponectin, IL-1β, and their combination for 24 h. Culture supernatant was collected and analyzed by enzyme-linked immunosorbent assay for levels of IL-6, IL-8, prostaglandin E(2) (PGE(2)), vascular endothelial growth factor (VEGF), and matrix metalloproteinases (MMPs). Adiponectin-mediated intracellular signaling pathways were investigated to elucidate the molecular mechanisms underlying their synergy. The association of proinflammatory mediators with adiponectin was investigated in the synovial fluid of arthritis patients. Adiponectin functioned synergistically with IL-1β to activate IL-6, IL-8, and PGE2 expression in RA fibroblast-like synoviocytes; Levels of VEGF, MMP-1, and MMP-13 were not synergistically stimulated. Adiponectin and IL-1β each increased the expression of both adiponectin receptor 1 and IL-1 receptor 1. However, adiponectin and IL-1β did not synergistically support the degradation of IκB-α or the nuclear translocation of NF-κB. Synergistically increased gene expression was significantly inhibited by MG132, an NF-κB inhibitor. Supporting the in vitro results, IL-6 and IL-8 levels were positively associated with adiponectin in synovial joint fluid from patients with RA, but not osteoarthritis (OA). In conclusion, adiponectin and IL-1β may synergistically stimulate the production of proinflammatory mediators through unknown signaling pathways during arthritic joint inflammation. Adiponectin may be more important to the pathogenesis of RA than previously thought.     

Highly sensitive turn-on detection of Ag+ in aqueous solution and live cells with a symmetric fluorescent peptide

This communication presents a symmetric fluorescent peptide (K(d) = 17.4 nM) for hypersensitively detecting Ag(+) in 100% aqueous solution by turn-on response. The peptide penetrated live HeLa cells and detected intracellular Ag(+) by turn-on response.     

J-aggregation induced low bandgap anthracene-based conjugated molecule for solution-processed solar cells

A new anthracene-based X-shaped conjugated molecule, HBTATHT, was synthesized. Thin film transistors based on unannealed HBTATHT showed a carrier mobility of 0.15 cm(2) V(-1) s(-1) (I(on/off) = 7.9 × 10(6)). Further, a solution processed solar cell made of HBTATHT exhibited promising power conversion efficiencies of 4.84% and 4.70% with PC(61)BM (1?:?0.8 wt ratio) and PC(71)BM (1?:?0.6 wt ratio), respectively.