Percolative dielectric behavior of wet chemical synthesized lead lanthanum titanate-cobalt iron oxide composite thin films

We have investigated the electrical and magnetic properties of solution synthesized Pb_0.85La_0.15TiO₃-CoFe₂O₄ composite thin films. These composite films exhibit both polarization as well as magnetic hysteresis characteristics at room temperature. The dielectric constant of the composite films is found to increase remarkably up to 6.0 vol% CFO contents. The increase of the dielectric constant and loss tangent follow a general percolation model originally developed for metal-ceramic composites. It is argued that Maxwell-Wagner polarization, as well as diffusion of transition metal cation(s) from CFO to PLT15 lattice are responsible for the percolative behavior of the dielectric properties in these films.     

Meromorphic functions with deficiencies generating unique range sets

With the help of weighted sharing of sets we deal with the problem of unique range set for meromorphic functions with deficient values and obtain a result which improves, generalizes and extends some previous results. We provide two examples to show that the condition in one of our results is the best possible.     

Investigations of sol–gel-derived highly (100)-oriented Ba0.5Sr0.5TiO3 : MgO composite thin films for phase-shifter applications

Sol–gel deposition of highly oriented Ba_0.5Sr_0.5TiO₃:MgO composite thin films has shown desirable dielectric constant reduction and higher figure of merit for phase-shifter applications. In this multilayer configuration, MgO distributed homogeneously through the Ba_0.5Sr_0.5TiO₃ (BST50) matrix, and it helped in tailoring the dielectric constant and reducing the loss tangent significantly. In the present study, the high-frequency dielectric behavior of the films has been evaluated by fabricating an eight-element coupled microstrip phase shifter and measuring the degree of phase shift and insertion loss as a function of applied voltage at room temperature. An increase in phase-shifter figure of merit (degree of phase shift per dB insertion loss) from 28°/dB for pure BST50 to 71°/dB for a BST50:MgO film (at 14 GHz and 333 kV/cm) has been observed. PACS 77.55.+f; 81.20.Fw; 73.40.-c; 85.50.-n     

Supramolecular Arrangement and DFT analysis of Zinc(II) Schiff Bases: An Insight towards the Influence of Compartmental Ligands on Binding Interaction with Protein

We report, for the first time, a detailed crystallographic study of the supramolecular arrangement for a set of zinc(II) Schiff base complexes containing the ligand 2,6-bis((E)-((2-(dimethylamino)ethyl)imino)methyl)-4-R-phenol], where R=methyl/tert-butyl/chloro. The supramolecular study acts as a pre-screening tool for selecting the compartmental ligand R of the Schiff base for effective binding with a targeted protein, bovine serum albumin (BSA). The most stable hexagonal arrangement of the complex [Zn − Me] (R=Me) stabilises the ligand with the highest FMO energy gap (ΔE=4.22 eV) and lowest number of conformations during binding with BSA. In contrast, formation of unstable 3D columnar vertebra for [Zn − Cl] (R=Cl) tend to activate the system with lowest FMO gap (3.75 eV) with highest spontaneity factor in molecular docking. Molecular docking analyses reported in terms of 2D LigPlot+ identified site A, a cleft of domains IB, IIIA and IIIB, as the most probable protein binding site of BSA. Arg144, Glu424, Ser428, Ile455 and Lys114 form the most probable interactions irrespective of the type of compartmental ligands R of the Schiff base whereas Arg185, Glu519, His145, Ile522 act as the differentiating residues with ΔG=−7.3 kcal mol⁻¹.     

Enantioselective transacetylation of (R,S)-β-citronellol by propanol rinsed immobilized Rhizomucor miehei lipase

Background  

Use of enzymes in low water media is now widely used for synthesis and kinetic resolution of organic compounds. The frequently used enzyme form is the freeze-dried powders. It has been shown earlier that removal of water molecules from enzyme by rinsing with n-propanol gives preparation (PREP) which show higher activity in low water media. The present work evaluates PREP of the lipase (from Rhizomucor miehei) for kinetic resolution of (R,S)-β-citronellol. The acylating agent was vinyl acetate and the reaction was carried out in solvent free media.     

Effect of tip functionalization on transport through vertically oriented carbon nanotube membranes

Ionic flux through a composite membrane structure, containing vertically aligned carbon nanotubes crossing a polystyrene matrix film, was studied as a function of chemical end groups at the entrance to carbon nanotubes' (CNTs) cores. Plasma oxidation during the membrane fabrication process introduced carboxylic acid groups on the CNTs' tips that were modified using carbodiimide mediated coupling between the carboxylic acid and an accessible amine groups of the functional molecule. Functionalization molecules included straight chain alkanes, anionically charged dye molecules, and an aliphatic amine elongated by polypeptide spacers. Functionalization was confirmed by FTIR spectroscopy, and areal functional density was estimated by transmission electron microscopy studies of thiol terminated sites decorated by nanocrystalline gold. The transport through the membrane of two different sized but equally charged molecules (ruthenium bipyridine [Ru-(bipy)3(2+)] and methyl viologen [MV2+]) was quantified in a U-tube permeation cell by UV-vis spectroscopy. Relative selectivity of the permeates varied from 1.7 to 3.6 as a function of tip-functionalization chemistry. Anionic charged functional groups sharply increased the flux of the cationic permeates. This effect was reduced at higher solution ionic strength consistent with shorter Debye screening length. The observed selectivities were consistent with a hindered diffusion model with functionalization at the CNT tip and not along the length of the CNT core.     

Black hole entropy with minimal length in tunneling formalism

Here we study the effects of the Generalized Uncertainty Principle in the tunneling formalism for Hawking radiation to evaluate the quantum-corrected Hawking temperature and entropy for a Schwarzschild black hole. We compare our results with the existing results given by other candidate theories of quantum gravity. In the entropy-area relation we found some new correction terms and in the leading order we found a term which varies as $\sim \sqrt{Area}$ ～ A r e a . We also get the well known logarithmic correction in the sub-leading order. We discuss the significance of this new quantum corrected leading order term.     

Ugi-type four-component reaction for a novel synthesis of 5-oxo-perhydrofuro[3,2-b]pyran carboxylate derivatives

The four-component coupling (4CC) of sugar hydroxyaldehyde, Meldrum’s acid, isocyanide, and a secondary alcohol in dichloromethane has been accomplished at room temperature in a highly stereoselective manner to produce a novel class of carbohydrate derivatives, 5-oxo-perhydrofuro[3,2-b]pyrans in good yields with trans-selectivity. The stereochemistry of the products was assigned by various NMR experiments.     

A study of the concentration of micro and macro nutrients in blenderised liquid diet in nasogastric feeding

Neutron activation analysis was used to determine the amount of macro (Na, K, P, Ca) and trace elements (Fe, Co, Zn, Mo, Se) present in the blenderised liquid diet in nasogastric feeding of patients having throat cancer.