Semidiscrete Galerkin method for equations of motion arising in Kelvin‐Voigt model of viscoelastic fluid flow

Finite element Galerkin method is applied to equations of motion arising in the Kelvin–Voigt model of viscoelastic fluids for spatial discretization. Some new a priori bounds which reflect the exponential decay property are obtained for the exact solution. For optimal L^∞( L ²) estimate in the velocity, a new auxiliary operator which is based on a modification of the Stokes operator is introduced and analyzed. Finally, optimal error bounds for the velocity in L^∞( L ²) as well as in L^∞( H )‐norms and the pressure in L^∞(L²)‐norm are derived which again preserves the exponential decay property. © 2012 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2013     

Dynamics of solid-melt front migration from a reaction–diffusion model

Using physical experiments we investigated the evolution of thermally driven melt patterns in a semi-infinite solid crystalline phase subjected to uniform heating from one side, maintaining melting temperature. We treat the melt initiation phenomenon theoretically in the perspective of two-phase interactions on the microscopic level, and propose a new reaction–diffusion model based on the prey–predator dynamics. This model predicts the fractal behavior of melt fronts observed in the experiments.     

Conformational aspects of caryophyllene. Population of stable conformers and ring inversion barrier of trans cyclononene ring portion

Cmr measurements of caryophyllene revealed two major conformers equilibrating in a ratio 76:24 at room temperature. The energy ordering of four possible conformers of caryophyllene predicted by molecular mechanics calculations agrees well with the experimental observation. The barrier of interconversion between the two conformers was determined as 16.25 kcal/mol.     

Twin tree hierarchy: a regularized approach to construction of signature matrices for overloaded CDMA

Overloaded code division multiple access being the only means of the capacity extension for conventional code division multiple access accommodates more number of signatures than the spreading gain. Recently, ternary Signature Matrices with Orthogonal Subsets (SMOS) has been proposed, where the capacity maximization is 200%. The proposed multi‐user detector using matched filter exploits the twin tree hierarchy of correlation among the subsets to guarantee the errorless recovery. In this paper, we feature the non‐ternary version of SMOS (i.e., 2k‐ary SMOS) of same capacity, where the binary alphabets in all the k constituent (orthogonal) subsets are unique. Unlike ternary, the tree hierarchy for 2k‐ary SMOS is non‐uniform. However, the errorless detection of the multi‐user detector remains undeviated. For noisy transmission, simulation results show the error performance of the right child for each subset of 2k‐ary to be significantly improved over the left. The optimality of the right child of the largest (Hadamard) subset is also discovered. At higher loading, for larger and smaller subsets the superiority is reported for the 2k‐ary and ternary, respectively, and the counter‐intuitive deviations observed for the lower loading scenarios are logically explained. For the overall capacity maximization being 150%, superiority is featured by the 2k‐ary, but beyond, it becomes a conditional entity. Copyright © 2016 John Wiley & Sons, Ltd.     

Interaction of ZnS nanoparticles with flavins and glucose oxidase: A fluorimetric investigation

Interactions of luminescence, water soluble ZnS nanoparticles (NPs) with flavins and glucose oxidase have been thoroughly investigated through optical spectroscopy. The photoluminescence of ZnS nanoparticles was quenched severely (～60%) by riboflavin while other flavins such as flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) show quenching to different extents under analogous conditions. However, interestingly no effect in luminescence intensity of ZnS NPs was observed with protein bound flavins such as in glucose oxidase. Fluorescence lifetime measurement confirmed the quenching to be static in nature. Scavenging of photo-generated electron of ZnS nanoparticles by the flavin molecules may be attributed to the decrease in luminescence intensity. Quenching of ZnS nanoparticles with flavins follows the linear Stern–Volmer plot. The Stern–Volmer constants decreased in the following order: K_S?V (Riboflavin)> K_S?V (FAD)> K_S?V (FMN). This interaction study could generate useful protocol for the fluorimetric determination of riboflavin (vitamin B₂) content and also riboflavin status in biological systems.     

Syntheses of Tri- and Tetrahydroxylated 1-Amino-Heptanes

Syntheses of tri- and tetrahydroxylated 1-amino-heptanes from α-D-glucose are described.     

A Mild and Efficient Alumina-Promoted Synthesis of t-Butyl Esters

A wide variety of aliphatic acid chlorides including an optically active one has been efficiently converted to their t-butyl esters under very mild reaction conditions by employing activated alumina as a catalyst.     

Thermodynamic and Fluorescence Studies on the Interaction of Cholesterol with Palmitoyl-Oleoyl Phosphatidylcholine and Sphingomyelin

Studies on the interaction of cholesterol (CHOL) with palmitoyl-oleoyl phosphatidylcholine (POPC) and sphingomyelin (SPM) are considered to be important because of the occurrence of strong interactions between sphingolipids and CHOL, which lead to the formation of microdomains or rafts within biological membranes. In the present investigation, studies on the surface pressure (π)-area ( A ) measurements and fluorescence microscopic studies on monolayers of the above mentioned system have been reported. Ideality/nonideality of mixing, excess area, and free energy changes during the formation of the monolayers at different surface pressures for the mixed lipid systems were evaluated from the π– A data. Interactions were found to be repulsive at lower CHOL content, which became associative at higher CHOL content. Condensing effects of CHOL on the mixed monolayers were found. Fluorescence studies on the systems revealed similar overall results.     

Cinnamoyl shikonin

The title compound, 1-(5,8-di­hydro-1,4-di­hydroxy-5,8-dioxo-2-naphthyl)-4-methyl­pent-3-en-1-yl cinnamate, C₂₅H₂₂O₆, crystallizes in space group P2₁. The phenyl ring of the cinnamate is anti to the carbonyl group of the same moiety [C—C—C—C = −175.6 (2)°] and is nearly parallel to the naphthyl ring system. Two six-membered rings formed by intramolecular hydrogen bonds, with O—H⃛O distances of 2.587 (2) and 2.589 (2) Å, occur on either side of the fused ring system, creating a tetracyclic pyrene-shaped system. The phenyl ring forms an intermolecular stack with the benzo­quinone ring, as a result of aromatic π–π interactions.