Cubic and Quartic Convergence for First-Order Periodic Boundary-Value Problems

In this paper, the results of Lakshmikantham et al. (Ref. 1) for first-order periodic boundary-value problems are extended, by using the extended method of quaislinearization and rapid convergence for initial-value problems of Mohapatra et al. (Ref. 2). Also, it is shown that monotone sequences converge cubically to the unique solution when the forcing function in the differential equation is 2–hyperconvex and converge quartically when the forcing function is 3–hyperconvex. Several other generalizations of the problem are also presented.     

An unusual extraction behavior of americium (III) and dioxouranium (VI) from picric acid medium using 18-crown-6 as neutral oxodonor

The extraction behavior of Am³⁺ and UO₂ ²⁺ is investigated employing chloroform solution of 18-crown-6 as the organic phase and picrate solution at pH 3.0 as the aqueous phase. In contrast to the commonly observed behavior, the extraction of Am³⁺ is preferred to that of UO₂ ²⁺. This unusual separation behavior is investigated as a function of several variable parameters such as crown ether concentration, picric acid concentration, inert electrolyte concentration, nature of diluent etc. Thermodynamic parameters are also evaluated.     

Separation of Aminoglycosides by Normal- and Reversed-Phase TLC

JPC – Journal of Planar Chromatography – Modern TLC - The normal-phase (NP) and reversed-phase (RP) thin-layer chromatographic separations of aminoglycosides (streptomycin, kanamycin,...     

A carbohydrate-based total syntheses of (+)-pyrenolide D and (-)-4-epi-pyrenolide D

Efficient total syntheses of (+)-pyrenolide D (5) and (-)-4-epi-pyrenolide D (6) have been achieved from a known 5-deoxy-d-xylose derivative 9 in ten steps with 19% overall yield either exclusively as 5 or as pure 5 and 6 in a 3:2 ratio. Key steps involved are one-pot epoxidation-cyclization by Corey-Chaykvosky reagent, reductive Barton-McCombie deoxygenation, and per-acid mediated oxidative spiroketalization.     

Effects of lattice dispersion and elastic anisotropy on the thermal properties of fcc metals

New parameters which separately take into account the effects of elastic anisotropy and phonon dispersion on the lattice specific heat in the case of fcc metals have been evaluated. A new graded mesh method which uses 162-direction approximation in (1/16) part of the Brillouin zone has been developed to evaluate the two new parameters.     

Double intramolecular oxymercuration: stereoselective synthesis of highly substituted bis-tetrahydrofuran

Stereoselective intramolecular oxymercuration has been demonstrated as the key reaction for the efficient preparation of mono- and dihydroxylated unsymmetrical bis-tetrahydrofuran skeletons present in naturally occurring biologically active acetogenins using carbohydrates. These trans- and syn-selective intramolecular oxymercurations were explored in an enantioselective synthesis of the bis-tetrahydrofuran skeleton of mucoxin.     

Quantitative Analysis of Corosolic Acid,a Type-II Anti-Diabetic Agent,in Different Parts of Lagerstroemia speciosa Linn.

JPC – Journal of Planar Chromatography – Modern TLC - An HPTLC method has been established for rapid and simple quantitative determination of corosolic acid, a type-II (non-insulin...     

Mixed Ligand Complexes of Zinc Acetylacetonate with substituted pyridines and quinolines-penta co-ordination

Zinc acetylacetonate was reacted in methanolic medium with substituted pyridines and quinolines, and eleven non-electrolytic, pentacoordinated mixed-ligand complexes [Zn(acac)₂L] have been isolated and characterised. The infra-red spectra indicate the presence of both acetylacetone and the bonded ligand.