Liquid chromatography‐tandem mass spectrometric method for determination of E121 in mouse plasma and its application to pharmacokinetics

A rapid LC‐MS/MS method for quantification of an enaminone analog, E121 in mouse plasma using E118 as an internal standard (IS) has been developed and validated. The analyte was analyzed on C₁₈ column using a mobile phase of acetonitrile/methanol/ammonium acetate/formic acid (60:20:20:0.025, v/v/v/v) at a flow rate of 0.25 mL/min. Quantitation was achieved using ESI+ interface, employing MRM mode at m/z 308>262 and 222>194 for E121 and IS, respectively. The calibration standards were linear over a range of 0.10–20 μg/mL (r²>0.99) with an LLOQ of 0.1 μg/mL (RSD%; 11.4% and bias%; 9.5%). Intra‐ and inter‐run precision of E121 assay ranged from 3.7 to 10.9% with accuracy (bias) that varied between ?10.0 and 12.0%, demonstrating good precision and accuracy. Recoveries of E121 and the IS from plasma were above 80%. Stability of E121 in plasma showed that the analyte was stable under various conditions. The matrix effect study showed a lack of effect. The applicability of the developed method was demonstrated by measuring E121 in mouse plasma samples following intraperitoneal administration of various doses ranging from 10 to 100 mg/kg and this study demonstrates that E121 exhibits linear kinetics in the dose range studied.     

Design,fabrication and characterization of a Schottky diode on an AlGaAs/GaAs HEMT structure for on-chip RF power detection

A Schottky diode was designed and fabricated on an n-AlGaAs/GaAs high electron mobility transistor (HEMT) structure for RF power detection. The processing steps used in the fabrication were the conventional steps used in standard GaAs processing. Current–voltage measurements showed that the devices had rectifying properties with a barrier height of 0.5289–0.5468 eV. The fabricated Schottky diodes detected RF signals well and their cut-off frequencies up to 20 GHz were estimated in direct injection experiments. To achieve a high cut-off frequency, a smaller Schottky contact area is required. The feasibility of direct integration with the planar dipole antenna via a coplanar waveguide transmission line without insertion of matching circuits was discussed. A higher cut-off frequency can also be achieved by reducing the length of the coplanar waveguide transmission line. These preliminary results represent a breakthrough as regards direct on-chip integration technology, towards the realization of a ubiquitous network society.     

Approximate solutions of fractional Zakharov–Kuznetsov equations by VIM

This paper presents the approximate analytical solution of a fractional Zakharov–Kuznetsov equation with the help of the powerful variational iteration method. The fractional derivatives are described in the Caputo sense. Several examples are given and the results are compared to exact solutions. The results show that the variational iteration method is very effective, convenient and simple to use.     

Approximate analytical solution for MHD stagnation-point flow in porous media

In this paper, the steady two-dimensional laminar forced MHD Hiemenz flow against a flat plate with variable wall temperature in a porous medium which was solved numerically using the implicit finite-difference of Keller-box method [Yih KA. The effect of uniform suction/blowing on heat transfer of magnetohydrodynamic Hiemenz flow through porous media. Acta Mech 1998;130:147–58] is revisited. A simple analytic approach of the Adomian decomposition method (ADM) is employed to obtain an approximate analytical solution of the problem. The skin friction coefficient and the rate of heat transfer given by the ADM are in good agreement with the numerical solutions of the Keller-box method.     

Application of multistage homotopy-perturbation method for the solutions of the Chen system

In this paper, a new reliable algorithm based on an adaptation of the standard homotopy-perturbation method (HPM) is applied to the Chen system which is a three-dimensional system of ODEs with quadratic nonlinearities. The HPM is treated as an algorithm in a sequence of intervals for finding accurate approximate solutions to the Chen system. We shall call this technique as the multistage HPM (for short MHPM). In particular we look at the accuracy of the HPM as the Chen system changes from a nonchaotic system to a chaotic one. Numerical comparisons between the MHPM and the classical fourth-order Runge–Kutta (RK4) numerical solutions reveal that the new technique is a promising tool for the nonlinear chaotic and nonchaotic systems of ODEs.     

Muon-pair production by atmospheric muons in CosmoALEPH

Data from a dedicated cosmic ray run of the ALEPH detector were used in a study of muon trident production, i.e., muon pairs produced by muons. Here the overburden and the calorimeters are the target materials while the ALEPH time projection chamber provides the momentum measurements. A theoretical estimate of the muon trident cross section is obtained by developing a Monte Carlo simulation for muon propagation in the overburden and the detector. Two muon trident candidates were found to match the expected theoretical pattern. The observed production rate implies that the nuclear form factor cannot be neglected for muon tridents.     

Ecowood Composites Made using Citric-Acidmodified Corn and Oil Palm Starches as the Binder

Mechanics of Composite Materials - The conventional wood-based composites contain an unreacted free formaldehyde, which causes a cancerous effect on humans. To overcome this problem,...     

Dynamics of the Hantavirus infection through variational iteration method

This paper studies the dynamics of the Hantavirus infection model, which was originally developed by Abramson and Kenkre [G. Abramson, V.M. Kenkre, Spatiotemporal patterns in the hantavirus infection, Phys. Rev. E 66 (2002) 011912], by using a simple analytical method called the variational iteration method or VIM. The results obtained by the variational iteration method are compared with the classical Runge–Kutta method (fourth-order) to gauge its effectiveness. Numerical values from these analyses provide us with some useful observation on the behaviour of the infection subjected to certain conditions.     

Accuracy of the Adomian decomposition method applied to the Lorenz system

In this paper, the Adomian decomposition method (ADM) is applied to the famous Lorenz system. The ADM yields an analytical solution in terms of a rapidly convergent infinite power series with easily computable terms. Comparisons between the decomposition solutions and the fourth-order Runge–Kutta (RK4) numerical solutions are made for various time steps. In particular we look at the accuracy of the ADM as the Lorenz system changes from a non-chaotic system to a chaotic one.