New alkaloids from Phoebe grandis (Nees) Merr

The alkaloidal extract of the leaves of Phoebe grandis (nees) merr. have provided two new minor alkaloids; phoebegrandine D (1), a proaporphine-tryptamine dimer, and phoebegrandine E (2), an indoloquinolizidine. This is the first report on the occurrence of an indoloquinolizidine in the Phoebe species. The crude extract also exhibited antiplasmodial activity (IC50<8 microg mL-1). The structures of the novel compounds were elucidated by spectroscopic methods, notably 2D NMR and HRMS.     

On an Implicit Method for Nonconvex Variational Inequalities

In this paper, we suggest and analyze an implicit iterative method for solving nonconvex variational inequalities using the technique of the projection operator. We also discuss the convergence of the iterative method under partially relaxed strongly monotonicity, which is a weaker condition than cocoerciveness. Our method of proof is very simple.     

On the Parametric Cubic Spline Approach for Solving Second Order Boundary Value Problems

In this article some comments on the paper “parametric cubic spline approach to the solution of a system of second order boundary value problems” in (Khan and Aziz, J. Optim. Theory Appl. 118:45–54, 2003) are given. This paper concerns with a numerical method for solving a second order boundary value problem associated with obstacle, unilateral and contact problems. Corrections are given for the convergence analysis of the numerical method and the computational experiments.     

Projection iterative methods for extended general variational inequalities

In this paper, we introduce and study a new class of variational inequalities involving three operators, which is called the extended general variational inequality. Using the projection technique, we show that the extended general variational inequalities are equivalent to the fixed point and the extended general Wiener-Hopf equations. This equivalent formulation is used to suggest and analyze a number of projection iterative methods for solving the extended general variational inequalities. We also consider the convergence of these new methods under some suitable conditions. Since the extended general variational inequalities include general variational inequalities and related optimization problems as special cases, results proved in this paper continue to hold for these problems.     

Falkner-Skan equation for flow past a stretching surface with suction or blowing: Analytical solutions

The simultaneous effects of suction and injection on tangential movement of a nonlinear power-law stretching surface governed by laminar boundary layer flow of a viscous and incompressible fluid beneath a non-uniform free with stream pressure gradient is considered. The self-similar flow is governed by Falkner-Skan equation, with transpiration parameter γ, wall slip velocity λ and stretching sheet (or pressure gradient) parameter β. The exact solution for β = −1 and three closed form asymptotic solutions for β large, large suction γ, and λ → 1 have also been presented. Dual solutions are found for β = −1 for each value of the transpiration parameter, including the non-permeable surface, for each prescribed value of the wall slip velocity λ. The large β asymptotic solution also dual with respect to wall slip velocity λ, but do not depend on suction and blowing. The critical values of γ, β and λ are obtained and their significance on the skin friction and velocity profiles is discussed. An approximate solution by integral method for a trial velocity profile is presented and results are compared with the exact solutions.     

Simplified SCF calculations on the diatomic alkali metal molecules

An account is given of a new formalism for calculating energy levels in molecules using techniques that derive from the band theory of metals. After showing how the molecular potential may be transformed into a cellular potential we define the basis set of muffin-tin orbitals and discuss some of their properties. The relationship between the scattered wave formulation of Johnson, which is restricted to muffin-tin potentials, and our more general approach based on the use of a linear combination of muffin-tin orbitals (L.C.M.T.O.) is explicitly indicated. We then show how the properties of the muffin-tin orbitals, together with the technique of cellular integration, give rise to a hamiltonian matrix. This matrix is as general as, but simpler than that obtained by the use of atomic orbitals, and it is linear in energy and therefore computationally faster than the secular matrix of the scattered wave method.     

Boundary Layer Flow over a Curved Surface Imbedded in Porous Medium

This research is made to visualize the boundary layer flow by a curved stretching sheet embedded in porous medium. The geometry is bended(curved), therefore the curvilinear coordinates are used to model the present problem.Fluid is electrically conducting with the presence of uniform magnetic field. The governing non-linear partial differential equation reduces to non-linear ordinary differential equations by using the dimensionless suitable transformations. The numerical solutions are obtained by using the method bvp4c from MATLAB. The effects of curvature parameter, nondimensional magnetic parameter, and porosity parameter on the velocity field and skin friction coefficient are examined.The skin friction profile enhances with enhancing the values of porosity and magnetic parameter. Comparison of the present results with the existing results in the literature for the flat surface is also given.     

Synthesis,Characterization, Antimicrobial Activity Screening,and Molecular Docking Study of Pyrimidine Carbonitrile Derivatives

Russian Journal of Organic Chemistry - The present work describes the synthesis of 4-amino-6-(2-benzylidenehydrazinyl)-pyrimidine-5-carbonitrile derivatives,...     

Rapid Estimation of Octanol–Water Partition Coefficient for Triazole Fungicides by MEKC with Sodium Deoxycholate as Surfactant

A rapid estimation of octanol–water partition coefficient (log P _ow) was developed for triazole fungicides by micellar electrokinetic chromatography (MEKC). Five standard compounds with known log P _ow values from 2.9 to 4.3 (cyproconazole, bromuconazole, epoxiconazole, bitertanol and difenoconazole) were used for constructing the calibration curve of the log P _ow against the MEKC retention factor, log k. A linear relationship was achieved between log P _ow and log k, in the MEKC system containing 40 mM sodium deoxycholate (SDC) and 4 mM borate buffer at pH 9.3, with a correlation of determination, r ² = 0.9905. The log P _ow values of four test compounds of triazole fungicides (triadimenol, myclobutanil, propiconazole and penconazole) were calculated based on the log k values measured by MEKC and the slope and intercept of the calibration curve. This MEKC method can give good estimation of the log P _ow of the four test compounds of triazole fungicides with the differences between the literature log P _ow values and estimated log P _ow from the MEKC method were from 0.15 to 0.23 log units.     

Synthesis of a palladium(II) complex of a <Emphasis Type="Italic">N</Emphasis>-heterocylic carbene via transmetalation: crystal structure and antibacterial studies

An Ag(I)-N-heterocylic carbene (NHC) complex, [Ag(L)₂]PF₆ (L = 1-(2′-methylbenzyl)-3-(2″-propyl)benzimidazolium), was used as a transfer agent for the synthesis of a Pd(II)–NHC complex, formulated as [PdCl(L)₂(MeCN)]PF₆ (Pd1). The complex Pd1 was characterized by ¹H and ¹³C NMR, FTIR spectroscopy and elemental analysis. Single crystal X-ray diffraction analysis reveals that the Pd(II) atom has a square planar geometry. This complex was screened for its antibacterial potential against the Gram-negative bacteria Escherichia coli (ATCC 25922) and the Gram-positive bacteria Staphylococcus aureus (ATCC 12600). These results are compared with those obtained for a standard antibiotic, ampicillin, and also the corresponding Ag(I)–NHC complex.