Thermophysical properties of neat and radiolytically degraded acidic extractants present in room temperature ionic liquid

In the present work, radon concentrations were measured in surface and underground water samples in Faridabad District of Southern Haryana, India using an active radon monitor based on alpha scintillation technique and results have been inter-compared. The average radon concentration in the underground water samples was observed to be 4 times higher than in the surface water samples. The estimated annual effective dose varied from 5.7 to 58.5 μSvy^?1 with an average of 24.2 μSvy^?1 for underground water samples and 1.1 to 12.5 μSvy^?1 with an average of 6.7 μSvy^?1 for surface water samples. The estimated annual effective dose for both type of samples was found to be less than 0.1 mSvy^?1, which is the safe limit as suggested by World Health Organisation and EU Council.

     

Chemical agents for binding post-translationally methylated lysines and arginines

Post-translational methylation, discovered more than half a century ago, encodes information in the form of a structural modification on a peptide or protein. The addition of a CH₃ group is one of the most subtle covalent modifications that exist in biology. In spite of this, recent years have revealed the many profound functional effects that arise from protein methylation in the cell. In an effort to open the doors to new assays and detection methods that would enable new basic and applied research into methylation pathways, chemical agents that can recognise and bind to methylated sites are now being pursued. In this review, we describe the supramolecular approaches to the recognition of methylated amino acids, peptides and proteins that have arisen in the last few years.     

A novel [Cu II 4] cluster from the assembly of two [Cu II 2L]+ units by a central mu4-1,1,2,2 perchlorate ligand

A perchlorate ligand in the rare mu4-1,1,2,2 binding mode is seen for the first time as the sole support for the assembly of two cationic [Cu II 2L]+ fragments (H3L = a dinucleating ligand) in the formation of a magnetically-exchanged tetranuclear cluster.     

Adsorption of basic fuchsin using waste materials--bottom ash and deoiled soya--as adsorbents

Basic fuchsin, a triaminotriphenylmethane dye, was removed by adsorption utilizing two waste materials--"bottom ash," a power plant waste material, and "deoiled soya," an agriculture waste product. The adsorbents were characterized through IR spectroscopy and differential thermal analysis (DTA). Batch adsorption experiments were carried out by measuring effects of pH, adsorbate concentration, sieve size, amount of adsorbent, contact time, temperature, etc. The results have been verified on the basis of Langmuir and Freundlich adsorption isotherm models and data obtained have been applied to calculate thermodynamic parameters. Specific rate constants for the processes were calculated by kinetic measurements and a pseudo-second-order adsorption kinetics was observed in each case. To identify whether the ongoing process is particle diffusion or film diffusion, the treatment given by Boyd and Reichenberg was employed. To assess the practical utility of the adsorbent, the aqueous adsorbate samples were eluted through fixed-bed columns of respective adsorbents. Attempts were also made to recover the adsorbed dyes by passing suitable solvent through the columns.     

Photodynamic efficacy of chlorin p6: a pH dependent study in aqueous and lipid environment

Photodynamic efficacy of chlorin p6, a potential candidate of photodynamic therapy (PDT), has been studied at pH 5.0, 6.0 and 7.6 in aqueous and lipid environment. Increased chlorin p6 mediated photodynamic bleaching of N,N-dimethyl-4-nitrosoaniline (RNO), a measure of singlet oxygen yield, was obtained at higher pH. Rate of photodynamic bleaching of RNO was also higher at higher pH and the rate decreased with lowering in pH of irradiated solution. Photodynamic oxidation of tryptophan was also found to be higher at higher pH. Diminished oxidation of RNO was obtained with decrease in pH of irradiated solution. Both, RNO bleaching and tryptophan oxidation was significantly reduced by sodium azide, a known quencher of singlet oxygen. At lower pH, chlorin p6 mediated photodynamic malondialdehyde (MDA) and lipid hydroperoxide formation in egg lecithin liposome was higher. At higher pH chlorin p6 was found to be photodynamically more effective in aqueous environment whereas at lower pH chlorin p6 was photodynamically more effective in hydrophobic environment.     

A one-dimensional energy diffusion approach to multidimensional dynamical processes in the condensed phase

We propose a generalized one-dimensional energy diffusion approach for describing the dynamics of multidimensional dynamical processes in the condensed phase. On the basis of a formalism originally due to Zwanzig, we obtain a one-dimensional kinetic equation for a properly selected relevant dynamical quantity and derive new analytical results for the dynamics of a multidimensional electron-transfer process, nonequilibrium solvation, and diffusive escape from a potential well. The calculated results for electron-transfer reactions in solvent-separated and contact ion pair systems are found to be in good agreement with the experimental results. We are able to explain the rate of the electron-transfer reaction using much smaller and reasonable values of the solvent reorganization energy in contrast to earlier works that had to use a much larger value. The proposed theory is not only conceptually simpler than the conventional approaches but is also free from many of their limitations. More importantly, it provides a single theoretical framework for describing a wide class of dynamical phenomena.     

Crystal structure of an ammonium thiocyanate complex of 18–crown–6

The title compound (C₁₃H₃₀N₂O₇S) has been determined from three‐dimensional X‐ray diffraction data. The crystals are monoclinic, a = 22.654(8) Å, b = 8.652(4) Å, c = 23.925(9) Å, β = 123.880(9)°, V = 3893(3) ų, Z = 8, D_calc = 1.192 g/cm³, space group C2/c. The structure was solved by direct methods and refined by full‐matrix least squares method (R = 0.051). The ammonium cation is displaced by 1.08 Å from the mean plane of the ligand causing hydrogen bonding with the macrocyclic O atoms in a perching arrangement. The thiocyanate anion forms an extended hydrogen bonded chain with the cation via the occluded water molecule. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Alterations in peristaltic pumping of Jeffery nanoliquids with electric and magnetic fields

The combined effects of electric and magnetic fields on peristaltic flow of Jeffery nanoliquids are analytically investigated. Double-diffusive convection in the asymmetric microchannel is also carried out. The walls of the microchannel are propagating with a finite phase difference in a sinusoidal manner. Rosseland diffusion flux model is employed to examine the thermal radiation effect. The zeta potential on the walls is considered very low to apply Hückel–Debye approximations. The coupled non-linear governing equations are simplified by using dimensional analysis and lubrication theory. The closed form solutions for potential function, nanoparticle fraction field, solute concentration field, temperature field, stream function, and axial velocity are derived under the appropriate boundary conditions. It is noteworthy that the pumping characteristics strongly depend on the magnetic fields, electric fields, electric double layer thickness, Jeffery parameter, thermal radiation and Grashof number. Furthermore, trapping phenomenon is analyzed under the effects of Hartmann number, Jeffrey parameter, Grashof number and Helmholtz–Smoluchowski velocity. The novelty of the present work is the amalgamation of biomimetics (peristaltic propulsion), electro-magneto-hydrodynamics and nanofluid dynamics to produce a smart pump system model for smart drug delivery systems.     

Dielectric properties of lanthanum-doped CaCu3Ti4O12 synthesized by semi-wet route

Effect of La³⁺ doping at Ca²⁺ site in CaCu₃Ti₄O₁₂ has been examined. Compositions with x=0.10, 0.20 and 0.30 were synthesized in the system Ca_(1−3x/2)La_xCu₃Ti₄O₁₂ by semi-wet method. Powder X-ray diffraction confirmed the formation of monophasic compounds. The structure remains cubic similar to CaCu₃Ti₄O₁₂. Lattice parameter increases slightly with increasing La³⁺ concentration. Microstructure has been studied using scanning electron microscopy (SEM). Average grain size is in the range 2-4 μm for various compositions. Energy-dispersive spectrometer (EDS) studies confirm the stoichiometry of the synthesized materials. Dielectric constant, dielectric loss and conductivity of the samples decrease with increasing lanthanum concentrations.     

Adsorption of Safranin-T from wastewater using waste materials- activated carbon and activated rice husks

Textile effluents are major industrial polluters because of high color content, about 15% unfixed dyes and salts. The present paper is aimed to investigate and develop cheap adsorption methods for color removal from wastewater using waste materials activated carbon and activated rice husk-as adsorbents. The method was employed for the removal of Safranin-T and the influence of various factors such as adsorbent dose, adsorbate concentration, particle size, temperature, contact time, and pH was studied. The adsorption of the dye over both the adsorbents was found to follow Langmuir and Freundlich adsorption isotherm models. Based on these models, different useful thermodynamic parameters have been evaluated for both the adsorption processes. The adsorption of Safranin-T over activated carbon and activated rice husks follows first-order kinetics and the rate constants for the adsorption processes decrease with increase in temperature.