Modified structure and electrical properties of BSZT doped KNN hybrid ceramic

Lead free (1?x)(K_0.5Na_0.5)NbO₃–x(Ba_0.9Sr_0.1)(Zr_0.1Ti_0.9)O₃ [(1?x)KNN–xBSZT] (x=0,0.02,0.04 and 0.06) ceramic were synthesized by a solid-state reaction method and the effects of BSZT doping on the electrical properties of KNN have been studied. X-ray diffraction (XRD) indicates that all the samples have single-phase perovskite structure and addition of BSZT forms a morphotropic phase boundary (MPB) i.e. the coexistence of orthorhombic and tetragonal phase in the region 0.02≤x≤0.04. Field emission scanning electron microscopy (FESEM) indicates the reduction in the grain size with the addition of BSZT. Small broadening in the dielectric peak arises at higher concentration of BSZT. The value of remnant polarization at x=0.04 is found to be higher than any other value of x except x=0 and also results in enhancement of dielectric constant at room temperature. Thereby it makes it useful for application at room temperature.     

Existence and numerical results of a transient lubrication problem with cavitation

This work is devoted to an existence result of a transient lubrication problem with a time dependent velocity and in the presence of cavitation which is modeled by the Elrod–Adams method. The existence of a solution is based on the time semi-discretization method which yields to a sequence of a second kind variational inequalities. We also give some numerical results for a journal bearing system.     

Cholesterol Sequestration from Caveolae/Lipid Rafts Enhances Cationic Liposome-Mediated Nucleic Acid Delivery into Endothelial Cells

Delivering nucleic acids into the endothelium has great potential in treating vascular diseases. However, endothelial cells, which line the vasculature, are considered as sensitive in nature and hard to transfect. Low transfection efficacies in endothelial cells limit their potential therapeutic applications. Towards improving the transfection efficiency, we made an effort to understand the internalization of lipoplexes into the cells, which is the first and most critical step in nucleic acid transfections. In this study, we demonstrated that the transient modulation of caveolae/lipid rafts mediated endocytosis with the cholesterol-sequestrating agents, nystatin, filipin III, and siRNA against Cav-1, which significantly increased the transfection properties of cationic lipid-(2-hydroxy-N-methyl-N,N-bis(2-tetradecanamidoethyl)ethanaminium chloride), namely, amide liposomes in combination with 1,2-Dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) (AD Liposomes) in liver sinusoidal endothelial cells (SK-Hep1). In particular, nystatin was found to be highly effective with 2–3-fold enhanced transfection efficacy when compared with amide liposomes in combination with Cholesterol (AC), by switching lipoplex internalization predominantly through clathrin-mediated endocytosis and macropinocytosis.     

Synthesis and Characterization of a Block Copolymer Containing Regioregular Poly(3‐hexylthiophene) and Poly(γ‐benzyl‐L‐glutamate)

Poly(3‐hexylthiophene)‐b‐poly(γ‐benzyl‐L ‐glutamate) (P3HT‐b‐PBLG) rod–rod diblock copolymer was synthesized by a ring‐opening polymerization of γ‐benzyl‐L ‐glutamate‐N‐carboxyanhydride using a benzylamine‐terminated regioregular P3HT macroinitiator. The opto‐electronic properties of the diblock copolymer have been investigated. The P3HT precursor and the P3HT‐b‐PBLG have similar UV–Vis spectra both in solution and solid state, indicating that the presence of PBLG block does not decrease the effective conjugation length of the semiconducting polythiophene segment. The copolymer displays solvatochromic behavior in THF/water mixtures. The morphology of the diblock copolymer depends upon the solvent used for film casting and annealing results in morphological changes for both films deposited from chloroform and trichlorobenzene.

     

Production of Keratinase by Free and Immobilized Cells of <Emphasis Type="Italic">Bacillus halodurans</Emphasis> Strain PPKS-2: Partial Characterization and Its Application in Feather Degradation and Dehairing of the Goat Skin

An extremely alkaliphilic bacterial strain, Bacillus sp. PPKS-2, was isolated from rice mill effluents and screened for the production of extracellular keratinase. The maximum production of keratinase occurred after 48 h in shaking culture at pH 11.0 and 37 °C in a medium containing 0.5% soybean flour. The strain grew and produced alkaline keratinase using chicken feather and horn meal as the sole source of carbon and nitrogen. An addition of 0.1% soybean flour or feather hydrolysate and sodium sulfite to feather medium increased the production and complete solubilization of feather took place within 5 days under solid-state fermentation conditions. The partially purified enzyme displayed maximum activity at pH 11.0 and 60 °C in a broad range of NaCl, 0–16%, and was not inhibited by sodium dodecyl sulfate (10%), ethylenediaminetetraacetic acid (10 mM), H₂O₂ (15%), and other commercial detergents. Immobilization of the whole cells proved to be useful for continuous production of keratinase and feather degradation. The enzyme was effectively used to remove hair from goat hide. The strain PPKS-2 can be effectively used for solid waste management of poultry feather in submerged as well as solid-state fermentation.     

Development of predictive pharmacophore model for in silico screening,and 3D QSAR CoMFA and CoMSIA studies for lead optimization,for designing of potent tumor necrosis factor alpha converting enzyme inhibitors

A chemical feature-based pharmacophore model was developed for Tumor Necrosis Factor-α converting enzyme (TACE) inhibitors. A five point pharmacophore model having two hydrogen bond acceptors (A), one hydrogen bond donor (D) and two aromatic rings (R) with discrete geometries as pharmacophoric features was developed. The pharmacophore model so generated was then utilized for in silico screening of a database. The pharmacophore model so developed was validated by using four compounds having proven TACE inhibitory activity which were grafted into the database. These compounds mapped well onto the five listed pharmacophoric features. This validated pharmacophore model was also used for alignment of molecules in CoMFA and CoMSIA analysis. The contour maps of the CoMFA/CoMSIA models were utilized to provide structural insight for activity improvement of potential novel TACE inhibitors. The pharmacophore model so developed could be used for in silico screening of any commercial/in house database for identification of TACE inhibiting lead compounds, and the leads so identified could be optimized using the developed CoMSIA model. The present work highlights the tremendous potential of the two mutually complementary ligand-based drug designing techniques (i.e. pharmacophore mapping and 3D-QSAR analysis) using TACE inhibitors as prototype biologically active molecules.     

Micropolar fluid flow through the membrane composed of impermeable cylindrical particles coated by porous layer under the effect of magnetic field

In the present work, the magnetohydrodynamic flow of a micropolar fluid through the membrane composed of impermeable cylindrical particles coated by porous layer is considered. The flow of a fluid is taken parallel to an axis of cylinder and a uniform magnetic field is applied in transverse direction of the flow. The problem is solved by using the cell model technique for the flow through assemblage of cylindrical particles. The solution of the problem has been obtained by using no-slip condition, continuity of velocity and stresses at interfaces along with Happle's no-couple stress condition as the boundary conditions. The expressions for the linear velocity, micro-rotational velocity, flow rate and hydrodynamic permeability of the membrane are achieved in this work. The obtained solution for velocities is used to plot the graph against various transport parameters such as, Hartmann number, coupling parameter, porosity, scaling parameter etc. The effect of these transport parameters on the flow velocity, micro-rotational velocity, and the hydrodynamic permeability of the membrane have been presented and discussed in this work.     

Compositionally controlled semimetal to superconducting transition in NaF doped LaOFeAs: Enhancement in Tc due to Na-doping

We report the synthesis of LaOFeAs based oxypnictide superconductors (La_1?xNa_xO_1?xF_xFeAs) using sodium fluoride as a fluorinating agent. NaF doping leads to a systematic decrease in both the a and c lattice parameters. Resistivity measurements show the onset resistivity transition temperature at 30.9 (±0.05) K and corresponding Meissner transition at 28 (±0.05) K in La_0.85Na_0.15O_0.85F_0.15FeAs which is highest in LaOFeAs type superconductors synthesized at ambient pressure. Further increase of NaF content in LaOFeAs leads to suppression of T_c. The above superconductors show a negative value of the Seebeck coefficient which indicates that electrons are the dominant charge carriers.     

The lithiation of 2-chloroglucal derivatives

Lithiation of 2-chloroglucal derivatives provides ready access to the corresponding 1-lithioglucals which undergo a variety of serve useful intermediates for further elaboration of the carbohydrate nucleus. Removal of the 2-chloro substituent may be affected using a Birch-type reduction.     

Volume visualization of payoff regions for derivatives risk management

Recently there has been research efforts to develop models and to use derivatives within a risk management program. However there has been not much effort to provide some insight into the type of conditions that tend to accompany the uses of derivatives. Once the type of risk has been identified, the next issue becomes the objective quantification of that risk. Regardless of the specific modeling approach employed, there are at least three key elements that need to be included in the quantification effort to enable subsequent risk management decisions: the volatility changes in risk profiling (direction of risk exposure), the Option's value determinant based on the underlying spot price (underlying assets and liabilities creating the risk exposure) and the days to maturity (term of risk exposure). As a result of addressing the above mentioned risk identification and quantification issues, we propose a new approach whereby it is fairly easy to construct a visual representation of the performance profile of the underlying portfolio. This research attempts to use volume visualization as the visual representation mechanism to quantify the risk and to visually estimate the payoff for derivatives risk management.