Quantum Complex Scalar Field in the Two-Dimensional Spacetime with Closed Timelike Curves and a Time-Machine Problem

It is considered the quantum complex scalar field which obeys the authomorphic condition in the two-dimensional spacetime with closed timelike curves and the chronology horizon. The renormalized stress-energy tensor is obtained. It is shown that the value of the stress-energy tensor is regular at the chronology horizon for specific authomorphic parameters. Thus the particular example of field configuration is given for which the Hawking's chronology protection conjecture is violated.Comment: 21(Latex)Postscript file of the figure may be received from author, CQG-94-100

On aspects of self-consistency in the Dyson-Schwinger approach to QED and \lambda (\phi^\star \phi)^2 theories

We investigate some aspects of the self-consistency in the Dyson-Schwinger approach to both the QED and the self-interacting scalar field theories. We prove that the set of the Dyson-Schwinger equations, together with the Green-Ward-Takahashi identity, is equivalent to the analogous set of integral equations studied in condensed matter, namely many-body perturbation theory, where it is solved self-consistently and iteratively. In this framework, we compute the non-perturbative solution of the gap equation for the self-interacting scalar field theory.Comment: 9 pages, to appear on Phys. Rev.

Supersymmetric Biorthogonal Quantum Systems

We discuss supersymmetric biorthogonal systems, with emphasis given to the periodic solutions that occur at spectral singularities of PT symmetric models. For these periodic solutions, the dual functions are associated polynomials that obey inhomogeneous equations. We construct in detail some explicit examples for the supersymmetric pairs of potentials V_{+/-}(z) = -U(z)^2 +/- z(d/(dz))U(z) where U(z) = \sum_{k>0}u_{k}z^{k}. In particular, we consider the cases generated by U(z) = z and z/(1-z). We also briefly consider the effects of magnetic vector potentials on the partition functions of these systems.Comment: Changes are made to conform to the published version. In particular, some errors are corrected on pp 12-1

Formalising the Continuous/Discrete Modeling Step

Formally capturing the transition from a continuous model to a discrete model is investigated using model based refinement techniques. A very simple model for stopping (eg. of a train) is developed in both the continuous and discrete domains. The difference between the two is quantified using generic results from ODE theory, and these estimates can be compared with the exact solutions. Such results do not fit well into a conventional model based refinement framework; however they can be accommodated into a model based retrenchment. The retrenchment is described, and the way it can interface to refinement development on both the continuous and discrete sides is outlined. The approach is compared to what can be achieved using hybrid systems techniques.Comment: In Proceedings Refine 2011, arXiv:1106.348

Divergences in the Effective Action for Acausal Spacetimes

The 1--loop effective Lagrangian for a massive scalar field on an arbitrary causality violating spacetime is calculated using the methods of Euclidean quantum field theory in curved spacetime. Fields of spin 1/2, spin 1 and twisted field configurations are also considered. In general, we find that the Lagrangian diverges to minus infinity at each of the nth polarised hypersurfaces of the spacetime with a structure governed by a DeWitt-Schwinger type expansion.Comment: 17 pages, Late

Interleukin-6 Increases Matrix Metalloproteinase-14 (MMP-14) Levels via Down-Regulation of p53 to Drive Cancer Progression

Matrix metalloproteinases (MMPs) play critical roles in cancer invasion and metastasis by digesting basement membrane and extracellular matrix (ECM). Much attention has focused on the enzymatic activities of MMPs; however, the regulatory mechanism of MMP expression remains elusive. By employing bioinformatics analysis, we identified a potential p53 response element within the MMP-14 promoter. Experimentally, we found that p53 can repress MMP-14 promoter activity, whereas deletion of this p53 response element abrogated this effect. Furthermore, we found that p53 expression decreases MMP-14 mRNA and protein levels and attenuates MMP-14-mediated cellular functions. Additional promoter analysis and chromatin immunoprecipitation studies identified a mechanism of regulation of MMP-14 expression by which p53 and transcription factor Sp1 competitively bind to the promoter. As the correlation between inflammation and cancer aggressiveness is well described, we next sought to evaluate if inflammatory cytokines could differentially affect p53 and MMP-14 levels. We demonstrate that interleukin-6 (IL-6) down-regulates p53 protein levels and thus results in a concomitant increase in MMP-14 expression, leading to enhanced cancer cell invasion and metastasis. Our data collectively indicate a novel mechanism of regulation of MMP-14 by a cascade of IL-6 and p53, demonstrating that the tumor microenvironment directly stimulates molecular changes in cancer cells to drive an invasive phenotype

The Effects of Cinnamon Supplementation on Plasma Lipid Concentrations: A Systematic Review and Meta-Analysis

Background: Cinnamon is a rich botanical source of polyphenols, whose positive effects on blood lipid concentrations have been hypothesized, but have not been conclusively studied. Objective: To systematically review and evaluate the effect of administration of cinnamon on blood lipid concentrations. Methods: We assessed 13 RCTs with 750 participants investigating the effect of cinnamon supplementation on blood lipid concentrations. A meta-analysis was performed using randomeffect models, with weighted mean differences (with 95% CI) for endpoints calculated using a random-effects model. Results: No statistically significant effect of cinnamon was observed on blood LDL-C (WMD: - 0.16 mmol/L [-6.19 mg/dL], 95% CI: -0.35, 0.03 [-13.53, 1.16], p = 0.10) and HDL-C (WMD: 0.05 mmol/L [1.92 mg/dL], 95% CI: -0.03, 0.12 [-0.03, 4.64], p = 0.21) concentrations. However, a statistically significant reduction in blood triglycerides (WMD: -0.27 mmol/L [- 23.91 mg/dL], 95% CI: -0.39, -0.14 [-34.54, -12.40], p < 0.01) and total cholesterol concentrations (WMD: -0.36 mmol/L [-13.92 mg/dL], 95% CI: -0.63, -0.09 [-24.36, -3.48], p < 0.01) was observed. HDL-C was significantly elevated following the omission of one study (WMD: 0.04 mmol/L [1.54 mg/dL], 95% CI: 0.03, 0.06 [1.16, 2.32], p < 0.01) during our sensitivity analysis. A meta-regression analysis was conducted and no significant association was found between changes in lipid parameters and cinnamon dose. In contrast, changes in blood levels of total cholesterol (slope: 0.09; 95% CI: 0.02, 0.16; p < 0.01), LDL-C (slope: 0.05; 95% CI: 0.001, 0.10; p = 0.05) and triglycerides (slope: 0.06; 95% CI: 0.04, 0.09; p < 0.01) were significantly and positively associated with the duration of supplementation. No statistically significant association was found between blood HDL-C changes and duration of supplementation. Conclusion: Cinnamon supplementation significantly reduced blood triglycerides and total cholesterol concentrations without any significant effect on LDL-C and HDL-C

Ecophysiology and dynamics of nitrogen removal bacteria in a sequencing batch reactor during wastewater treatment start‑up

Nitrogen removal communities performing wastewater treatment consist of ammonia oxidisers, nitrite oxidisers, denitrifiers, and anammox bacteria, and the proportion and activity of particular microbial groups depend not only on the physiochemical parameters of the bioreactor, but also on the composition of the inoculum. Nitrifiers and denitrifiers usually dominate in conventional wastewater treatment systems due to the fact that nitrification and denitrification are the most commonly used nitrogen removal processes. However, from the economical point of view in case of wastewater with high ammonia concentrations, anammox-based technologies are desirable for their treatment. The disadvantage of such systems is slow anammox bacteria growth, which extends an effective technological start-up. Thus, in this study, a fast start-up of the anammox process supported with an anammox-rich inoculum was performed in a sequencing batch reactor (SBR). Using anammox inoculation of SBR laboratory system, the start-up can be fastened to 85 days with 84.5% of nitrogen removal efficacy. The spatial distribution of nitrogen removal bacteria analysed with fluorescent in situ hybridisation revealed that anammox and nitrifiers are located side by side in the flocs and the relative number of ammonia and nitrite oxidisers decreased after 85 days of the experiment