GASTRO-PROTECTION OF ATORVASTATIN IN INDOMETHACIN-INDUCED ULCER: ROLE OF TUMOR NECROSIS FACTOR-ALPHA AND PROSTAGLANDINS

Using non-steroidal anti-inflammatory drugs as over-the-counter pain-killers may predispose to gastric ulcer as a side effect.The objective of this study is to investigate the possible benefit of a common statin used in hyperlipedemic patients;atorvastatin (AtoR), in ameliorating the ulcerogenic effect of indomethacin (IndoM), and to explore the possible mechanismsinvolved. AtoR (10 mg/kg/day) was administered orally for 7 days. At day 7, gastric ulcer was induced by a single dose ofIndoM (40 mg/kg i.p.), with or without AtoR pre-treatment. IndoM induced gastric ulcer as evident by notable gastriculceration in histopathological sections compared to normal control. Gastric tissue in rats receiving IndoM showedsignificantly higher oxidative stress markers as lipid peroxidation represented by increased malondialdehyde (MDA)content, with significant decrease in gastric tissue nitric oxide (NO) and prostaglandin E2 (PGE2) levels, as well as reductionin catalase and superoxide dismutase antioxidant enzymatic activities. In addition, IndoM induced inflammatory signs asshown by the significant increase in tumor necrosis factor-alpha (TNF-α) level assessed via ELISA. Pre-administration ofAtoR significantly decreased ulcer index (16±1) compared to that of IndoM alone (34±2). In addition, AtoR restored normalgastric histological structure and reverted oxidative and inflammatory markers tested. AtoR confers gastro-protection againstIndoM-induced ulceration via reducing gastric oxidative stress and increasing gastric NO and PGE2 levels, as well asdecreasing the inflammatory marker; TNF-α

A probabilistic characterization of adhesive wear in metals

Adhesive wear is one of the predominant mechanisms responsible for mechanical component failures that result in a huge economic loss. Adhesive wear has been studied; the deterministic model formulated by Archard is frequently used. However, its parameters, such as material-hardness and wear coefficient show a considerable variation around the nominal value; this variation necessitates a statistical framework for studying the wear law. This paper treats these parameters as probabilistic quantities. Investigation of the model involved an experiment consisting of a pin-on-bushing machine. Load and sliding speed are used as variables while the geometry and material of the friction couple are constant. The generated data are analyzed using simple statistical methods. The randomness of wear and hardness are best modeled by the Weibull distribution, whereas the wear coefficient is modeled by a log normal distribution. Scatter parameters and median life of wear are explored for various velocities as time progresses; the median life characteristics are mathematically modeled. The application of these models in accelerated wear testing is highlighted; accelerating by increasing the speed of operation provides a better extrapolation as compared to using heavier load

A probabilistic characterization of adhesive wear in metals

Adhesive wear is one of the predominant mechanisms responsible for mechanical component failures that result in a huge economic loss. Adhesive wear has been studied; the deterministic model formulated by Archard is frequently used. However, its parameters, such as material-hardness and wear coefficient show a considerable variation around the nominal value; this variation necessitates a statistical framework for studying the wear law. This paper treats these parameters as probabilistic quantities. Investigation of the model involved an experiment consisting of a pin-on-bushing machine. Load and sliding speed are used as variables while the geometry and material of the friction couple are constant. The generated data are analyzed using simple statistical methods. The randomness of wear and hardness are best modeled by the Weibull distribution, whereas the wear coefficient is modeled by a log normal distribution. Scatter parameters and median life of wear are explored for various velocities as time progresses; the median life characteristics are mathematically modeled. The application of these models in accelerated wear testing is highlighted; accelerating by increasing the speed of operation provides a better extrapolation as compared to using heavier load

Silica-based chelating resin bearing dual 8-Hydroxyquinoline moieties and its applications for solid phase extraction of trace metals from seawater prior to their analysis by ICP-MS

Solid phase extraction (SPE) using chelating resins has been established as a convenient technique for samples pretreatment prior to trace metal analysis from complex matrices. Oxine chelating agents (e.g., 8-Hydroxyquinoline (8-HQ)) are popular moieties in the synthesis of chelating resins, due to their characteristic coordination chemistry. So far most of the reported silica-oxine chelators encompasses a single oxine molecule per spacer arm. In this work, two 8-HQ ligands have been covalently attached onto silica surface throughout a single linkage. The synthesized resin characterized with FTIR, elemental analysis and SEM. The main parameters affecting SPE procedures, such as pH, and sorption kinetics, investigated using batch experiments. The capacity exchange of the produced resin under optimized conditions was 0.219 and 0.161 mmol g−1 for Cu(II) and Mn(II) respectively. The resin packed into 10 ml standard cartridges and used with a typical SPE manifold for matrix removal prior to an ICP-MS analysis of transition metals (i.e., Cu, Cd, Ni, Pb, Zn, and Co) in seawater certified reference material samples and real samples from high saline seawater near the discharge zone of Yanbu desalination plant. The obtained results confirm the usefulness of the method.The authors are grateful for the Scientific Research Deanship, Taibah University for the generous financial support, grant No. 766/432

General structure of the photon self-energy in non-commutative QED

We study the behavior of the photon two point function, in non-commutative QED, in a general covariant gauge and in arbitrary space-time dimensions. We show, to all orders, that the photon self-energy is transverse. Using an appropriate extension of the dimensional regularization method, we evaluate the one-loop corrections, which show that the theory is renormalizable. We also prove, to all orders, that the poles of the photon propagator are gauge independent and briefly discuss some other related aspects.Comment: 16 pages, revtex4. This is the final version to be published in Phys. Rev.

Lattice Perturbation Theory in Noncommutative Geometry and Parity Anomaly in 3D Noncommutative QED

We formulate lattice perturbation theory for gauge theories in noncommutative geometry. We apply it to three-dimensional noncommutative QED and calculate the effective action induced by Dirac fermions. In particular "parity invariance" of a massless theory receives an anomaly expressed by the noncommutative Chern-Simons action. The coefficient of the anomaly is labelled by an integer depending on the lattice action, which is a noncommutative counterpart of the phenomenon known in the commutative theory. The parity anomaly can also be obtained using Ginsparg-Wilson fermions, where the masslessness is guaranteed at finite lattice spacing. This suggests a natural definition of the lattice-regularized Chern-Simons theory on a noncommutative torus, which could enable nonperturbative studies of quantum Hall systems.Comment: 31 pages. LaTeX, feynmf. Minor changes, references added and typos corrected. Final version published in JHE

Effects of viscous dissipation and boundary conditions on forced convection in a channel occupied by a saturated porous medium

Forced convection with viscous dissipation in a parallel plate channel filled by a saturated porous medium is investigated numerically. Three different viscous dissipation models are examined. Two different sets of wall conditions are considered: isothermal and isoflux. Analytical expressions are also presented for the asymptotic temperature profile and the asymptotic Nusselt number. With isothermal walls, the Brinkman number significantly influences the developing Nusselt number but not the asymptotic one. At constant wall heat flux, both the developing and the asymptotic Nusselt numbers are affected by the value of the Brinkman number. The Nusselt number is sensitive to the porous medium shape factor under all conditions considered

Effects of viscous dissipation and boundary conditions on forced convection in a channel occupied by a saturated porous medium

Forced convection with viscous dissipation in a parallel plate channel filled by a saturated porous medium is investigated numerically. Three different viscous dissipation models are examined. Two different sets of wall conditions are considered: isothermal and isoflux. Analytical expressions are also presented for the asymptotic temperature profile and the asymptotic Nusselt number. With isothermal walls, the Brinkman number significantly influences the developing Nusselt number but not the asymptotic one. At constant wall heat flux, both the developing and the asymptotic Nusselt numbers are affected by the value of the Brinkman number. The Nusselt number is sensitive to the porous medium shape factor under all conditions considered

Image Quality Assessment Using Spatial Frequency Component

Image quality assessment (IQA) is a crucial technique in perceptual image/video coding, because it is not only a ruler for performance evaluation of coding algorithms but also a metric for ratio-distortion optimization in coding. In this paper, inspired by the fact that distortions of both global and local information influence the perceptual image quality, we propose a novel IQA method that inspects these information in the spatial frequency components of the image. The distortion of the global information mostly existing in low spatial frequency is measured by a rectified mean absolute difference metric, and the distortion of the local information mostly existing in high spatial frequency is measured by SSIM. These two measurements are combined using a newly proposed abruptness weighting that describes the uniformity of the residual image. Experimental results on LIVE database show that the proposed metric outperforms the SSIM and achieves performance competitive with the state-of-the-art metrics. ? 2009 Springer-Verlag Berlin Heidelberg.EI