Extraction of neodymium(III) using binary mixture of Cyanex 272 and Cyanex 921/Cyanex 923 in kerosene

The extraction of Nd(III) using binary mixtures of Cyanex 272 (HA), Cyanex 921/Cyanex 923 (B) in kerosene from nitric acid medium has been investigated. The effect of aqueous phase acidity, extractant concentration, nitrate ion concentration and diluents on the extraction of Nd(III) has been studied. On the basis of slope analysis results, extracted species are proposed as Nd(NO₃)A₂·3HA and Nd(NO₃)₂·A·3HA·B using Cyanex 272 and its mixture with Cyanex 921/Cyanex 923, respectively. With the mixture of 0.1 M Cyanex 272 and 0.1 M Cyanex 923 in kerosene, the extraction of 0.001 M Nd(III) from 0.001 M HNO₃ solution was found to be 83.3 % whereas it was 73.3 % when 0.1 M Cyanex 921 used as synergist under same experimental conditions. The stripping data of Nd(III) from the loaded organic phase containing 0.1 M Cyanex 272 and 0.1 M Cyanex 921/Cyanex 923 with different acids indicated sulphuric acid to be the best stripping agent.     

Synthesis of polyhydroxylated indolizidines and piperidines from Garner's aldehyde: total synthesis of (−)-swainsonine, (+)-1,2-di-epi-swainsonine, (+)-8,8a-di-epi-castanospermine,pentahydroxy indolizidines, (−)-1-deoxynojirimycin, (−)-1-deoxy-altro-nojirimycin,and related diversity

Diastereoselective and diverse synthesis of polyhydroxylated indolizidines and piperidines have been described, where a common chiral intermediate 2-(hydroxymethyl) piperidine-3-ol is converted into (−)-swainsonine, (+)-1,2-di-epi-swainsonine, (+)-8,8a-di-epi-castanospermine, pentahydroxy indolizidines, (−)-1-deoxynojirimycin, (−)-1-deoxy-altro-nojirimycin, and related diversity. The key steps were hydroxy directed intramolecular aminomercuration, Mitsunobu cyclization, and diastereoselective dihydroxylation.     

Laminar diffusion of suspended particulate matter using a two phase flow model

The present paper envisages laminar mixing of a two‐dimensional jet of particulate suspension in an incompressible carrier fluid with a free stream in direction of the jet axis. Finite difference technique has been employed for finding out solution of governing equations. It is found that the diffusion parameter ε, the ratio of particle diffusion coefficient and kinematic viscosity of the carrier fluid, have significant influence on the concentration of particles. A large value of ε has the effect in increasing the perturbation velocity u_p and perturbation density ρ_p. It is observed that the volume fraction φ, has no significant effect on perturbation velocity u and u_p but has profound effect on perturbation velocity v and v_p. It is also found that the particle phase as well as the carrier fluid velocity attain free stream value for the large ξ, the modified x‐co‐ordinate. Further the magnitude of the perturbation quantities u, u_p, v, v_p decreases as ξ increases i.e. at far away from the nozzle exit. Copyright © 2002 John Wiley & Sons, Ltd.     

A new solution method for fuzzy chance constrained programming problem

This paper deals with an optimization model, where both fuzziness and randomness occur under one roof. The concept of fuzzy random variable (FRV), mean and variance of FRV is used in the model. In particular, the methodology is developed in the presence of FRV in the constraint. The methodology is verified through numerical examples.     

Analytic methods for field induced tunneling in quantum wells with arbitrary potential profiles

Electric field induced tunneling is studied in three different types of quantum wells by solving time-independent effective mass equation in analytic methods based on three different Airy function approaches. Comparison of different Airy function methods indicates that they are identical and connected to each other by the Breit-Wigner formula.     

Synthesis and Utility of Dihydropyridine Boronic Esters

When activated by an acylating agent, pyridine boronic esters react with organometallic reagents to form a dihydropyridine boronic ester. This intermediate allows access to a number of valuable substituted pyridine, dihydropyridine, and piperidine products.     

Water-soluble cyclodiphosphazanes: synthesis, gold(I) metal complexes and their in vitro antitumor studies

The newly synthesized water-soluble cyclodiphosphazane ligands and their gold(I) complexes inhibit HeLa cell proliferation by activating p53 protein and inducing apoptosis.     

Enhanced fluorescence of epicocconone in surfactant assemblies as a consequence of depth-dependent microviscosity

The extents of fluorescence enhancement of epicocconone are found to be different in the micelles of the surfactants sodium dodecyl sulfate (SDS) and Triton X100 (TX 100). A decrease in fluorescence, observed in the cationic cetyltrimethylammonium bromide (CTAB) micelles, is rationalized by the formation of anions of the fluorophore at the Stern layer. To understand the difference in the effects of SDS and TX 100, the nature of the excited-state process in the fluorophore has been investigated by fluorescence spectroscopy, supported by complementary quantum chemical calculations. The excited-state dynamics of epicocconone is found to depend on polarity and viscosity of the medium, with a more pronounced dependence on viscosity. An inspection of the molecular orbitals involved in the electronic absorption of the molecule reveals the possibility of photoisomerization, which conforms to the observed solvent dependence of the fluorescence spectral properties. An apparent mismatch between trends observed in steady-state spectra and those in temporal decays indicates a significant contribution of an ultrafast component, which cannot be detected in the time resolution of our instrument. The viscosity dependence of the fluorescence quantum yields provides an explanation for the difference in the extents of fluorescence enhancement in the two micelles, in the light of location of the fluorophore at different depths of the micelle. The enhancement of fluorescence, with an unchanged fluorescence maximum, opens up the possibility that the fluorophore could be a useful dual emitting marker for fluorescence microscopy of heterogeneous systems, as the fluorescence of protein-bound epicocconone has been previously reported to be significantly red-shifted.     

A new example of a steroid-amino acid hybrid: construction of constrained nine membered D-ring steroids

A new archetype of steroid-amino acid hybrids containing a nine membered D-ring with hetero atoms has been synthesized for the first time from estrone and amino acids by using Yamaguchi coupling reactions.     

Convenient phosphorus tribromide induced syntheses of substituted 1-arylmethylnaphthalenes from 1-tetralone derivatives

A series of 1-arylmethylnaphthalenes 7a-g and 11 have been synthesized conveniently in good yields at room temperature through phosphorus tribromide induced aromatization of 1-aryl-[3,4]-dihydronaphthyl-methanols 6a-g and 10, which were obtained from 1-tetralone derivatives.