Solution structure of copper-seamed C-alkylpyrogallol[4]arene nanocapsules with varying chain lengths

The stability of copper-seamed C-alkylpyrogallol[4]arene hexamers with varying chain lengths in solution has been studied using small-angle neutron scattering (SANS). The progression in diameter of spherical capsules with increasing alkyl chain lengths of copper-seamed hexamers in solution suggests both robustness as well as a close correlation between the solid phase and solution phase structures.     

A rapid and simple route for the synthesis of lead and palladium nanoparticles in tetrazolium based ionic liquid

In the present work, we report a novel method for the synthesis of palladium and lead nanoparticles by the reduction method in tetrazolium ring based ionic liquid. Palladium and lead nanoparticles so-prepared were well characterized by powder X-ray diffraction measurements (pXRD), transmission electron microscopy (TEM) and quasi elastic light scattering (QELS) techniques. Powder X-ray diffraction (pXRD) analysis revealed all relevant Bragg's reflection for crystal structure of palladium and lead. Powder X-ray diffraction plots also revealed no oxidized material of palladium and lead nanoparticles. TEM showed nearly uniform distribution of the particles in methanol and confirmed by QELS. Typical applications of palladium nanoparticles include in vitro use and sensor design applications. Palladium nanoparticles is also ideal for spin coating, self-assembly and monolayer formation. Palladium nanoparticles can also be considered as potential new catalysts.     

Antimicrobial investigation of Linum usitatissimum for the treatment of acne

Light petroleum, dichloromethane and methanolic extracts of Linum usitatissimum were investigated using GC/MS. The main components of three sequential extracts were methyl linolenate (11.9-33.9%) and methyl linoleate (3.4-9.1%). Components possessing antimicrobial activity against acne causing bacteria, namely alpha-linolenic acid (7.0 -7.1%), alpha-terpinene (1.7-3.1%), terpinen-4-ol (1.3-4.6%), 4-cymene (1.6-7.1%) and alpha-pinene (1.1%), were found in varying amounts. Antimicrobial screening indicated that the light petroleum extract was more active against aerobic and anaerobic test strains with a MIC value of 1.25 mg/mL and a MBC of 2.5 mg/mL against S. aureus and P. acnes. A MIC of 2.5 mg/mL was observed against S. epidermidis.     

Thermosolutal convection in a Maxwellian viscoelastic fluid in porous medium

The thermosolutal convection in a layer of Maxwellian viscoelastic fluid heated and soluted from below in porous medium is considered. The effects of uniform magnetic field and uniform rotation on the thermosolutal convection are also considered. For stationary convection, the Maxwellian viscoelastic fluid behaves like a Newtonian fluid. The sufficient conditions for the nonexistence of overstability are obtained. The critical Rayleigh number is found to increase with the increase in magnetic field, rotation and stable solute gradient.     

Orientational order in liquid crystals exhibited by some binary mixtures of rod-like and bent-core molecules

We report measurements of the temperature variations of the optical birefringence in the nematic (N) and partial bilayer SmA (SmA_d) phases in 4-n-octyloxy 4^′ -cyanobiphenyl made of rod-like (R) molecules and five mixtures of this compound with 1,3-phenylene bis[4-(3-methylbenzoyloxy)] 4^′ -n- dodecylbiphenyl 4^′ -carboxylate, made of bent-core (BC) molecules. The birefringence decreases with the concentration x of the BC molecules but the macroscopic order parameter initially decreases upto 11mol% of BC molecules and subsequently increases with x . This is attributed to the possible formation of polar clusters of BC molecules. Orientation of BC molecules changes between the N and SmA_d phases and the birefringence data in the two phases imply that the kink angle of the BC molecules is ∼ 90^° rather than ∼ 110^° as obtained from calculations which minimize the energy of the molecule. IR spectroscopic measurements on the mixture with 11mol% of BC molecules have been used to estimate the molecular order parameter S of the R molecules, and to provide additional support for a relatively small kink angle of BC molecules.     

Charged Analogue of Whittaker’s Interior Solution

Charged analogue of Whittaker’s interior solution is derived which possess constant gravitational mass density (ρ+3p). The solution joins smoothly to Nordstörm solution at the pressure free interface. The solution has increasing energy density away from the center which is unphysical however such model can very well represent the situations when density undergoes abrupt changes during the tug of war between the gravitational attraction and electrostatic repulsion.     

Electric field and temperature dependence of hole mobility in electroluminescent PDY 132 polymer thin films

The current density–voltage ($J\text{–}V$) behavior of polymer PDY 132 thin films has been investigated in hole-only device configuration, viz., ITO/poly(ethylene-dioxthiophene):polystyrenesulphonate (PEDOT:PSS)/PDY 132/Au, as a function of polymer (PDY) film thickness (150 nm and 200 nm) and temperature (290–90 K). Hole current density was found to follow two distinct modes of conduction, (i) low electric field region I: ohmic conduction where slope $～1$, and (ii) intermediate and high electric field region II: non ohmic conduction where slope $～2$. Region I has been attributed to the transport of intrinsic background charge carriers while region II has been found to be governed by space charge limited currents (SCLC) with hole mobility strongly dependent on electric field and temperature. The respective hole transport parameters determined from the SCLC regime, ${\mu }_{p0}$ is $3.7\times 10^{?3}{m}^2/Vs$, ${\mu }_p(0,T)$ is $3.7\times 10^{?8}{m}^2/Vs$, and zero field activation energy (${\Delta }_0$) of 0.48 eV is obtained.     

A parameter-uniform scheme for singularly perturbed partial differential equations with a time lag

A numerical scheme for a class of singularly perturbed delay parabolic partial differential equations which has wide applications in the various branches of science and engineering is suggested. The solution of these problems exhibits a parabolic boundary layer on the lateral side of the rectangular domain which continuously depends on the perturbation parameter. For the small perturbation parameter, the standard numerical schemes for the solution of these problems fail to resolve the boundary layer(s) and the oscillations occur near the boundary layer. Thus, in this paper to resolve the boundary layer the extended cubic B-spline basis functions consisting of a free parameter λ are used on a fitted-mesh. The extended B-splines are the extension of classical B-splines. To find the best value of λ the optimization technique is adopted. The extended cubic B-splines are an advantage over the classical B-splines as for some optimized value of λ the solution obtained by the extended B-splines is better than the solution obtained by classical B-splines. The method is shown to be first-order accurate in t and almost the second-order accurate in x. It is also shown that this method is better than some existing methods. Several test problems are encountered to validate the theoretical results.