NCOS and D-branes in Time-dependent Backgrounds

We study noncommutative open string (NCOS) theories realized in string theory with time-dependent backgrounds. Starting from a noncommutative Yang-Mills theory (NCYM) with a constant space-space noncommutativity but in a time-dependent background and making an S-dual transformation, we show that the resulting theory is an NCOS also in a time-dependent background but now with a time-dependent time-space noncommutativity and a time-dependent string scale. The corresponding dual gravity description is also given. A general SL(2,Z) transformation on the NCYM results in an NCOS with a time-dependent time-space noncommutativity and a constant space-space noncommutativity, and also in a time-dependent background.Comment: 12 pages, references added; v3: minor correction, to appear in PL

Time-varying Reliability Analysis of Long-span Continuous Rigid Frame bridge under Cantilever Construction Stage based on the Monitored Strain Data

Abstract: In general, the material properties, loads, resistance of the prestressed concrete continuous rigid frame bridge in different construction stages are time-varying. So, it is essential to monitor the internal force state when the bridge is in construction. Among them, how to assess the safety is one of the challenges. As the continuous monitoring over a long-term period can increase the reliability of the assessment, so, based on a large number of monitored strain data collected from the structural health monitoring system (SHMS) during construction, a calculation method of the punctiform time-varying reliability is proposed in this paper to evaluate the stress state of this type bridge in cantilever construction stage by using the basic reliability theory. At the same time, the optimal stress distribution function in the bridge mid-span base plate is determined when the bridge is closed. This method can provide basis and direction for the internal force control of this type bridge in construction process. So, it can reduce the bridge safety and quality accidents in construction stages

Lusin-type approximation of Sobolev by Lipschitz functions, in Gaussian and RCD(K,∞)RCD(K,\infty) spaces

We establish new approximation results, in the sense of Lusin, of Sobolev functions by Lipschitz ones, in some classes of non-doubling metric measure structures. Our proof technique relies upon estimates for heat semigroups and applies to Gaussian and $RCD(K, \infty)$ spaces. As a consequence, we obtain quantitative stability for regular Lagrangian flows in Gaussian settings

Synthesis of Bis-β-Diketonate Lanthanide Complexes with an Azobenzene Bridge and Studies of Their Reversible Photo/Thermal Isomerization Properties.

The ligand, bis-β-diketone with an azobenzene bridge (4,4’-(4,4,4-trifluoro-1,3-butanedione)azobenzene, H 2 L ), was prepared for the synthesis of a series of dinuclear lanthanide complexes with the formula [Ln 2 L 3 (DMSO) 4 ] (Ln = Eu3+, Gd3+, Tb3+, and DMSO = dimethyl sulfoxide). X-ray crystallographic analysis reveals that the three complexes are triple-stranded dinuclear structures formed by three bis-β-diketonate ligands with two lanthanide ions (Ln3+). The trans-to-cis photoisomerization rates of the azobenzene group of the three [Ln 2 L 3 (DMSO) 4 ] complexes in ethanol and acetonitrile solutions are similar to those of the pure H 2 L ligand and other azobenzene-containing mononuclear lanthanide complexes, but the trans-to-cis quantum yields (Φt→c = 10-3) are 1 order of magnitude smaller. The first-order rate constant for the cis-to-trans thermal isomerization at 50 °C of the H 2 L ligand is similar to those of azobenzene derivatives, while those for the [Ln 2 L 3 (DMSO) 4 ] complexes ( k iso = 10-4 s-1) are higher than those of the mononuclear azobenzene-containing lanthanide complexes. Furthermore, as the lanthanide ionic radius becomes smaller from Eu3+ to Gd3+ to Tb3+, the thermal isomerization rate constant decreases and the half-life increases. All these results are proposed to arise from the rigidity at both ends of the azo group by coordination to the dinuclear lanthanide ions and the different isomerization mechanisms. These are the first examples of bis-β-diketonate dinuclear lanthanide complexes with an azobenzene bridge and help illustrate the mechanism of azobenzene isomerization

A Mode-Sum Prescription for Vacuum Polarization in Even Dimensions

We present a mode-sum regularization prescription for computing the vacuum polarization of a scalar field in static spherically-symmetric black hole spacetimes in even dimensions. This is the first general and systematic approach to regularized vacuum polarization in higher even dimensions, building upon a previous scheme we developed for odd dimensions. Things are more complicated here since the even-dimensional propagator possesses logarithmic singularities which must be regularized. However, in spite of this complication, the regularization parameters can be computed in closed form in arbitrary even dimensions and for arbitrary metric function $f(r)$. As an explicit example of our method, we show plots for vacuum polarization of a massless scalar field in the Schwarzschild-Tangherlini spacetime for even $d=4,...,10$. However, the method presented applies straightforwardly to massive fields or to nonvacuum spacetimes.Comment: arXiv admin note: text overlap with arXiv:1609.0816

Robust high-temperature magnetic pinning induced by proximity in YBa2Cu3O7-8/La0.67Sr0.33MnO3 hybrids

An elaborately designed bilayer consisting of superconducting YBa2Cu3O7-6 (YBCO) and ferromagnetic La0.67Sr0.33MnO3-6 (LSMO) was prepared on a single crystal LaAlO3 substrate by pulsed laser deposition (PLD), with a view to understanding the mechanism behind the influence of superconductor/ferromagnet proximity on the critical current density, Jc. The present bilayer system shows significant modifications in Jc, as evidenced by the suppressed decay of its temperature dependence, as well as the crossing behavior of the magnetic field dependence of Jc at high temperatures. This indicates that enhanced flux pinning emerges at high temperatures, and it is believed to arise from the special magnetic inhomogeneity, i.e., the ferromagnet/antiferromagnet clusters caused by phase separation due to the epitaxial stress between LSMO and the substrate

Critical behavior for the dilaton black holes

We study the critical behavior in the black p-branes and four dimensional charged dilaton black holes. We calculate the thermodynamic fluctuations in the various (microcanonical, canonical, and grandcanonical) ensembles. It is found that the extremal limit of some black configurations has a critical point and a phase transition takes place from the extremal to nonextremal black configurations. Some critical exponents are obtained, which satisfy the scaling laws. This is related to the fact that the entropy of these black configurations is a homogeneous function.Comment: 33 pages, RevTex, no figure

High expression of transcriptional coactivator p300 correlates with aggressive features and poor prognosis of hepatocellular carcinoma

<p>Abstract</p> <p>Background</p> <p>It has been suggested that p300 participates in the regulation of a wide range of cell biological processes and mutation of p300 has been identified in certain types of human cancers. However, the expression dynamics of p300 in hepatocellular carcinoma (HCC) and its clinical/prognostic significance are unclear.</p> <p>Methods</p> <p>In this study, the methods of reverse transcription-polymerase chain reaction (RT-PCR), Western blotting and immunohistochemistry (IHC) were utilized to investigate protein/mRNA expression of p300 in HCCs. Receiver operating characteristic (ROC) curve analysis, spearman's rank correlation, Kaplan-Meier plots and Cox proportional hazards regression model were used to analyze the data.</p> <p>Results</p> <p>Up-regulated expression of p300 mRNA and protein was observed in the majority of HCCs by RT-PCR and Western blotting, when compared with their adjacent non-malignant liver tissues. According to the ROC curves, the cutoff score for p300 high expression was defined when more than 60% of the tumor cells were positively stained. High expression of p300 was examined in 60/123 (48.8%) of HCCs and in 8/123 (6.5%) of adjacent non-malignant liver tissues. High expression of p300 was correlated with higher AFP level, larger tumor size, multiplicity, poorer differentiation and later stage (<it>P </it>< 0.05). In univariate survival analysis, a significant association between overexpression of p300 and shortened patients' survival was found (<it>P </it>= 0.001). In different subsets of HCC patients, p300 expression was also a prognostic indicator in patients with stage II (<it>P </it>= 0.007) and stage III (<it>P </it>= 0.011). Importantly, p300 expression was evaluated as an independent prognostic factor in multivariate analysis (<it>P </it>= 0.021). Consequently, a new clinicopathologic prognostic model with three poor prognostic factors (p300 expression, AFP level and vascular invasion) was constructed. The model could significantly stratify risk (low, intermediate and high) for overall survival (<it>P </it>< 0.0001).</p> <p>Conclusions</p> <p>Our findings provide a basis for the concept that high expression of p300 in HCC may be important in the acquisition of an aggressive phenotype, suggesting that p300 overexpression, as examined by IHC, is an independent biomarker for poor prognosis of patients with HCC. The combined clinicopathologic prognostic model may become a useful tool for identifying HCC patients with different clinical outcomes.</p