A Lorentz Invariance Violating Cosmology on the DGP Brane

We study cosmological implications of a Lorentz invariance violating DGP-inspired braneworld scenario. A minimally coupled scalar field and a single, fixed-norm, Lorentz-violating timelike vector field within an interactive picture provide a wide parameter space which accounts for late-time acceleration and transition to phantom phase of the scalar field.Comment: 23 pages, 8 figures, accepted for publication in JCA

Comprehensive characterization of the Published Kinase Inhibitor Set

Despite the success of protein kinase inhibitors as approved therapeutics, drug discovery has focused on a small subset of kinase targets. Here we provide a thorough characterization of the Published Kinase Inhibitor Set (PKIS), a set of 367 small-molecule ATP-competitive kinase inhibitors that was recently made freely available with the aim of expanding research in this field and as an experiment in open-source target validation. We screen the set in activity assays with 224 recombinant kinases and 24 G protein-coupled receptors and in cellular assays of cancer cell proliferation and angiogenesis. We identify chemical starting points for designing new chemical probes of orphan kinases and illustrate the utility of these leads by developing a selective inhibitor for the previously untargeted kinases LOK and SLK. Our cellular screens reveal compounds that modulate cancer cell growth and angiogenesis in vitro. These reagents and associated data illustrate an efficient way forward to increasing understanding of the historically untargeted kinome

Chemically Modified Electrode with a Film of Nano Ruthenium Oxides Stabilizing High Valent RuO4- Species and Its Redox-Selective Sequential Transformation to Polynuclear Ruthenium Oxide-Metallocyanates

High-valent (RuO4-)-O-VII (perruthenate) is a short-lived species in aqueous solutions (pH 1-14) and has scarcely been studied through electrochemistry. By a potential-controlled oxidative deposition method at I V vs Ag/AgCl using RuCl3 in a pH 2 KCl-HCl buffer solution, chemically modified glassy carbon (GCE) and indium tin oxide (ITO) electrodes were successfully prepared with a Film of hydrous nano ruthenium oxides RuO2 and RuO3, stabilizing the high-valent perruthenate anion (Ru(VII)-RuOx-CME, x = 2 and 3, CME = chemically modified electrode). The electrodes showed three distinct redox peaks corresponding to Ru2O3/RuO2, RuO2/RuO3, and RuO42-/RuO4- redox processes at pH 2, like the classical RuO2 electrodes in alkaline conditions. Solid state UV-visible spectra of the ITO/Ru(VII)-RuOx-CME showed characteristic absorption very close to chemically generated authentic RuO4 species in alkaline solution. Further, redox-controlled sequential procedures yielded polynuclear ruthenium oxide-hexacyanometallate films (RuOMCN-CME, M = Fe and Ru), in which Ru(VII)-RuOx-CME acted as a specific template. A controlled-potential activation (> 1 V) of Ru(VII)-RuOx-CME, stabilizing the key RuO4- species, in a solution of [Fe(CN)(6)](3-) or [Ru(CN)(6)](4-), should be a critical step for the formation of polynuclear RuO-MCN matrix

Simultaneous detection of NADH and H2O2 using flow injection analysis based on a bifunctional poly(thionine)-modified electrode

We report here a novel detection scheme for simultaneous detection of NADH and H2O2 based on a bifunctional poly(thionine)-modified electrode. Electropolymerization of thionine on a "preanodized" screen-printed carbon electrode effectively lowers the oxidation potential of NADH to 0.15 V (vs. Ag/AgCl). Since poly(thionine) is also a well known electrochemical mediator for H2O2 reduction, we further developed a poly(thionine)-modified ring disk electrode for simultaneous measurement of nicotinamide adenine dinucleotide (NADH) and hydrogen peroxide (H2O2) by flow injection analysis. By applying the optimized detection potentials of 0.2 V and -0.2 V at disk and ring electrodes, respectively, this system allows the simultaneous measurement of both analytes with good sensitivity (0.13 mu A/mM for H2O2 and 0.34 mu A/mM for NADH) and limit of detection (1.74 mu M and 26.0 mu M for NADH and H2O2). This opens the possibility of a whole series of biosensor applications. (C) 2011 Elsevier B.V. All rights reserved

Electrochemical investigation of glucose sensor fabricated at copper-plated screen-printed carbon electrodes

Copper-plated screen-printed carbon electrode (CuSPE) provides a suitable catalytic surface for the amperometric detection of hydrogen peroxide, Glucose oxidase (GOD) is immobilized on the top of the CuSPF to form a glucose sensor. The interaction of copper oxide with GOD was found to be an important factor in the glucose detection. Preliminary investigation under hydrodynamic conditions showed a linear calibration plot up to 26.7 mM glucose with a slope and regression coefficient of 4.5 muA/mM and 0.9902. respectively. The Michaelis-Menten kinetics by nonlinear curve fitting yielded a K-m value close to that in solution indicating the ideality and suitability of the present system. Classical mixed potential mechanism is for the first time applied to the enzyme-coated CuSPE to further understand the system

A selective voltammetric method for uric acid detection at Nafion (R)-coated carbon paste electrodes

A square-wave voltammetric method together with Nafion(R)-coated carbon paste electrodes were used for the selective determination of uric acid in the presence of a high concentration of ascorbic acid. Since the oxidation potential of uric acid is about 200 mV more positive than that of ascorbic acid at the Nafion(R)-coated carbon paste electrode, the selectivity can be greatly improved simply by applying an electrolysis potential of + 0.4 V vs. Ag/AgCl where only ascorbic acid is oxidised. The acceptable tolerance of ascorbic acid concentration for the determination of uric acid is as high as 1.5 mM. With 30 s of electrolysis time, a linear calibration curve is obtained over the 0-50 mu M range in 0.05 hi citrate buffer solution, pH 4.0, with slope (mu A/mu M) and correlation coefficient of 0.34 and 0.9984, respectively. The detection limit (30) is 0.25 mu M. The practical analytical utility is illustrated by selective measurements of uric acid in human urine without any preliminary treatment. (C) 1998 Elsevier Science B.V. All rights reserved

Characteristic and electrocatalytic behavior of ruthenium Prussian blue analogue film in strongly acidic media

The remarkable stability of ruthenium Prussian blue analogue (designated as RuOx-PB) in strongly acidic media and for the enzymeless electrocatalytic oxidation of glucose was demonstrated in this study. The RuOx-PB combinative film neither dissolves nor denatures in concentrated acids, such as HClO4, HCl, H2SO4, and HNO3, investigated in this study. The catalytic response was found to directly proportional to [H+]. Such features are unique since neither RuOx- nor PB-based compounds are effective for direct carbohydrate oxidation in acidic media. The RuOx-PB film showed a highly reversible redox peak at similar to 1.2 V in 5 M HClO4 as a result of the fast proton-coupled electron transfer behavior of high valent ruthenium intermediate, Ru-VII/VI. The formation of internal multiple-hydrogen bond as well as the generation of the > Ru-VII=O species in strongly acidic media were proposed to play a key role in this feature. The RuOx-PB holds high potential for use in catalytic oxidation, corrosion protection, biofuel cell, etc. (c) 2006 Elsevier B.V All rights reserved

Voltammetric determination of kojic acid in cosmetic bleaching products using a disposable screen-printed carbon electrode

A preanodized screen-printed carbon electrode is used for the determination of kojic acid in cosmetic bleaching products by square-wave voltammetry. The preanodization process leads to a marked enhancement of the current response of kojic acid at the screen-printed carbon electrode. The linear range is up to 260 mu M in pH 10 Britton-Robinson buffer with a detection limit (S/N=3) of 0.17 mu M. The electrode has the advantages of low cost, of being easy to handle, and it can be either disposable or reused since the renewal gives a reproducible surface. Quantitative analysis for the kojic acid content in cosmetic products was performed by the standard addition method