2-(2-Selenocyanic acid ethyl ester)-1H-benz[de] isoquinoline-1,3-(2H)-dione, synthesis photophysics and interaction with bovine serum albumin: a spectroscopic approach

The compound 2-(2-selenocyanic acid ethyl ester)-1H-benz[de] isoquinoline-1,3-(2H)-dione (SEBID), a ubiquitous, bioactive naphthalimide derivative is expected to possess an anticancer, anti-tumor and other important therapeutic activities of significant potency with low systematic toxicity. In this paper, the synthesis of the compound, photophysics of the newly prepared naphthalimide derivative and its interaction with model transport protein Bovine serum albumin (BSA) have been reported using the absorption and steady state fluorescence spectroscopic techniques exploiting the intrinsic fluorescence emission properties of BSA as a probe. Interaction of this organoselenium compound in different dioxane-water mixtures with increase in the polarity of the medium has been studied spectroscopically. Interaction of SEBID with BSA leads to a dramatic decrease in the fluorescence intensity of BSA, which suggests the binding of SEBID with the tryptophan residue of BSA. Furthermore, different thermodynamic parameters for SEBID-BSA interaction have been calculated. Rationalization of the data has been attempted, particularly in relation to prospective applications in the biomedical research.     

An interesting ring contraction of a class of bromohydrins and trans-dibromides

An efficient ring contraction of stereoisomeric 1,2-benzo-4-bromo-3-hydroxycyclohept-1-ene and their derivatives (1a-e) to (2a-c) is reported, and a probable mechanism for this ring contraction has been suggested.     

Spectrophotometric determination of bismuth,cobalt, and nickel after extraction of their xanthates with molten naphthalene

Summary A new method for the spectrophotometric determination of bismuth, cobalt and nickel after extraction of their xanthates into molten naphthalene is described. The optimum pH values are 2.4–4.5 for Bi, 7.5–9.0 for Co, 5.5–7.5 for Ni. The naphthalene containing the metal chelates is dissolved in chloroform, and the absorbance is measured against a reagent blank at 362, 350 and 420 nm for Bi, Co and Ni and respectively. Few ions interfere and the method has been applied successfully for the determination of these metal ions in various complex materials.

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Zusammenfassung Eine neue Methode für die spektrophotometrische Bestimmung von Wismuth, Kobalt und Nickel nach Extraktion ihrer Xanthate mit geschmolzenem Naphthalin wurde beschrieben. Das optimale pH für Wismut beträgt 2,4–4,5, für Kobalt 7,5–9,0 und für Nickel 5,5–7,5. Das die Metallchelate enthaltende Naphthalin wird in Chloroform gelöst und die Extinktion gegen eine Reagens-Leerlösung bei 362, 350 bzw. 420 nm für Bi, Co bzw. Ni gemessen. Nur wenige Ionen stören. Das Verfahren wurde mit Erfolg zur Bestimmung der genannten Ionen in verschiedenen komplexen Gemischen angewandt.

     

Molecular-dynamics simulation of model polymer nanocomposite rheology and comparison with experiment

The shear-rate dependence of viscosity is studied for model polymer melts containing various concentrations of spherical filler particles by molecular-dynamics simulations, and the results are compared with the experimental results for calcium-carbonate-filled polypropylene. Although there are some significant differences in scale between the simulated model polymer composite and the system used in the experiments, some important qualitative similarities in shear behavior are observed. The trends in the steady-state shear viscosities of the simulated polymer-filler system agree with those seen in the experimental results; shear viscosities, zero-shear viscosities, and the rate of shear thinning are all seen to increase with filler content in both the experimental and simulated systems. We observe a significant difference between the filler volume fraction dependence of the zero-shear viscosity of the simulated system and that of the experimental system that can be attributed to a large difference in the ratio of the filler particle radius to the radius of gyration of the polymer molecules. In the simulated system, the filler particles are so small that they only have a weak effect on the viscosity of the composite at low filler volume fraction, but in the experimental system, the viscosity of the composite increases rapidly with increasing filler volume fraction. Our results indicate that there exists a value of the ratio of the filler particle radius to the polymer radius of gyration such that the zero-shear-rate viscosity of the composite becomes approximately independent of the filler particle volume fraction.     

Microwave assisted green chemical synthesis of novel spiro[indole-pyrido thiazines]: a system reluctant to be formed under thermal conditions

Spiro [3H-indole-3,2′-[4H] pyrido [3,2-e]-1,3-thiazine]-2,4′ (1H) diones, a class of previously unknown compound which does not form under conventional conditions, can be prepared by treatment of ‘in situ’ generated 3-indolylimine derivatives with 2-mercaptonicotinic acid under microwave irradiation in absence of any solvent or solid support in 85-92% yields in 3-8 min. The facile one pot reaction is generalized for a variety of ketones and amines to give pure pyrido [3,2-e] thiazine derivatives, which do not require further purification processes.     

Mixed-ligand and binuclear complexes of oxovanadium(IV)

Summary Mixed ligand complexes of the type [VOLA]ClO₄ where L=5-bromosalicylaldehyde (L) or 5-nitrosalicylaldehyde (L) and A=2, 2-dipyridyl (A) or 1, 10-phenanthroline (A) have been prepared. Treatment of the mononuclear complexes, [VOLA]ClO₄, withp-phenylenediamine (ppd) orm-phenylenediamine (mpd) yielded homobinuclear [VOLA-NC₆H₄N-LAVO](ClO₄)₂, complexes, which were characterised by elemental analyses, spectra, magnetic susceptibility and molar conductance measurements.     

Partitioning of quencher ions in the micellar microenvironment of polyoxyethylene nonyl phenol

This paper has explored the quenching of fluorescence of the dye safranine T (ST) by the inorganic cations viz Cu2+, Co2+, Ni2+ and Mn2+ in micellar solutions of the surfactant dioxyethylene nonyl phenol (Igepal CO-210), pentaoxyethylene nonyl phenol (Igepal CO-520) and dodecaoxyethylene nonyl phenol (Igepal CO-720). The quenching results have been calculated in light of stern volmer equation (SV) to evaluate the extent of interaction between the fluorophore (ST) and quencher. The average concentration of the quencher ions in the micelle have been determined. The quenching efficiency of ST by inorganic ions in micellar medium is lower than that in aqueous medium. The results show that the ions get partitioned in the micellar medium. The values of the partition coefficient of the ions decrease with increase in HLB value and number of oxyethylene groups in Igepal.     

Rearrangement correction to higher polarizabilities of two-electron systems

In this paper we include the rearrangement correction (discussed in the preceding paper) in a coupled Hartree–Fock (CHF) calculation of atomic hyperpolarizabilities and other related properties. We have studied the effect of these corrections on properties like electric dipole hyperpolarizabilities, uniform electric field quadrupole polarizabilities and shielding factors in two-electron ions and have noticed significant changes in the computed values over the CHF results.     

A Pollution Sensitive Marxian Production Inventory Model with Deterioration Under Fuzzy System

Journal of Optimization Theory and Applications - This article deals with an economic production quantity (EPQ) model with deterioration under the effect of environmental pollution in fuzzy...     

Superconvergence error estimates of discontinuous Galerkin time stepping for singularly perturbed parabolic problems

Numerical Algorithms - A parabolic convection-diffusion-reaction problem is discretized by the non-symmetric interior penalty Galerkin (NIPG) method in space and discontinuous Galerkin (DG) method...