Reductive metabolism of nitro-p-phenylenediamine by rat liver

Reductive metabolism of the hair dye constituent, nitro-p-phenylenediamine (2-nitro-1,4-diaminobenzene, NPDA), and its acetylated metabolite, NPDA N4-acetate, was investigated with rat liver subcellular fractions, microsomes and cytosol. Under anaerobic conditions, these compounds were reduced to their corresponding amines by these fractions. The microsomal nitro-reducing activity was retarded completely by air and strongly by carbon monoxide. Reduced nicotinamide adenine dinucleotide phosphate (NADPH) functioned more effectively than reduced nicotinamide adenine dinucleotide (NADH) as an electron donor in the microsomal reduction of the nitro compounds, and flavin mononucleotide (FMN) gave rise to a marked enhancement in the microsomal activity, especially when added to an anaerobic incubation mixture containing both NADH and NADPH. The cytosolic nitro-reducing activity was attributed to xanthine oxidase, aldehyde oxidase and other unknown enzyme(s), based on the results of cofactor requirements and inhibition experiments.     

Numerical verification of stationary solutions for Navier–Stokes problems

We present a numerical method to enclose stationary solutions of the Navier–Stokes equations, especially 2-D driven cavity problem with regularized boundary condition. Our method is based on the infinite dimensional Newton's method by estimating the inverse of the corresponding linearized operator. The method can be applied to the case for high Reynolds numbers and we show some numerical examples which confirm us the actual effectiveness.     

Error estimates of a Galerkin method for some nonlinear Sobolev equations in one space dimension

Summary A semidiscrete Galerkin finite element method is defined and analyzed for nonlinear evolution equations of Sobolev type in a single space variable. Optimal orderL ^p error estimates are derived for 2p. And it is shown that the rates of convergence of the approximate solution and its derivative are one order better than the optimal order at certain spatial Jacobi and Gauss points, respectively. Also the standard nodal superconvergence results are established. Futher, it is considered that an a posteriori procedure provides superconvergent approximations at the knots for the spatial derivatives of the exact solution.     

Waiakeamide, a Cyclic Hexapeptide from the Sponge Ircinia dendroides(1)

From the sponge, Ircinia dendroides, collected in Indonesia we isolated a new cyclic hexapeptide, waiakeamide (1). Its structure, consisting of three proline residues, two methionine sulfoxides, and one thiazolylphenylalanine, was elucidated by spectral analysis and chemical degradation. Isolation and structural elucidation of waiakeamide is described.