Nanostructured CuO/SrTiO3 bilayered thin films for photoelectrochemical water splitting

Bilayered thin films of CuO/SrTiO₃ with varying thickness of CuO were deposited by sol–gel spin-coating technique on indium tin oxide substrate and used as photoelectrode in the photoelectrochemical cell for water splitting reaction. Maximum photocurrent density of 1.85 mA/cm² at ?0.9 V/saturated calomel electrode was exhibited by 590-nm-thick CuO/SrTiO₃ bilayered photoelectrode, which is approximately eight times higher than that for CuO and 30 times higher than that for SrTiO₃. The bilayered system offered increased photocurrent density and enhanced photoconversion efficiency, attributed to improved conductivity, which ameliorate separation of the photo-generated carriers at the CuO/SrTiO₃ interface and higher value of flatband potential. Details about synthesis and various characterisations involving X-ray diffraction and scanning electron microscopy have been discussed. An energy band diagram has been proposed to dwell upon the mechanism of charge carrier transfer across the interface.     

Inhibitory potential of Hydroxychavicol on Ehrlich ascites carcinoma model and in silico interaction on cancer targets

Abstract

Hydroxychavicol (HC), a major phenolic derivative isolated from the leaves of Piper betle L. is well known for its antibacterial, antifungal and antimutagenic properties. The present study evaluated the in vivo antitumor activity of HC against Ehrlich Ascites Carcinoma (EAC) cells in Swiss albino mice and in silico interaction of HC with the receptors involved in the cancer. Hydroxychavicol (200 and 400?mg/kg bw) was orally administered for 21 consecutive days and was effective in inhibiting the tumor growth in ascitic mouse model. HC consistently reduced the tumor volume, viable cell count, lipid peroxidation and elevated the life span of HC treated mice. Besides the hematological profiles, SGOT and SGPT levels reverted back to normal and oxidative stress markers GSH, SOD and CAT also increased in HC treated groups. In silico docking analysis revealed that HC possessed potent antagonist activity against all the cancer targets demonstrating its inhibitory activity.     

Conformational changes in beta-endorphin as studied by electrospray ionization mass spectrometry.

Because of a wide range of physiological functions, the structure of beta-endorphin (BE) is of great interest. In this study, conformational changes in BE induced by methanol are explored with electrospray ionization-mass spectrometry (ESI-MS). Differences in the charge-state distribution (CSD) and the extent of hydrogen/deuterium (H/D) exchange were used to monitor the conformational changes. The latter experiments were conducted via time-resolved ESI-MS in a continuous-flow apparatus. Both these techniques demonstrate that BE exists in a random coil open structure in aqueous media, but it acquires a more compact conformation with increased concentration of methanol. The H/D exchange experiments reveal that BE forms 61% alpha-helix in mixed solvents.     

A class of higher order compact schemes for the unsteady two‐dimensional convection–diffusion equation with variable convection coefficients

A class of higher order compact (HOC) schemes has been developed with weighted time discretization for the two‐dimensional unsteady convection–diffusion equation with variable convection coefficients. The schemes are second or lower order accurate in time depending on the choice of the weighted average parameter μ and fourth order accurate in space. For 0.5?μ?1, the schemes are unconditionally stable. Unlike usual HOC schemes, these schemes are capable of using a grid aspect ratio other than unity. They efficiently capture both transient and steady solutions of linear and nonlinear convection–diffusion equations with Dirichlet as well as Neumann boundary condition. They are applied to one linear convection–diffusion problem and three flows of varying complexities governed by the two‐dimensional incompressible Navier–Stokes equations. Results obtained are in excellent agreement with analytical and established numerical results. Overall the schemes are found to be robust, efficient and accurate. Copyright © 2002 John Wiley & Sons, Ltd.     

Isentropic compressibility, effective pressure, classical sound absorption and shear relaxation time of aqueous lithium bromide, sodium bromide and potassium bromide solutions

Densities, speeds of sound and viscosities of aqueous lithium bromide, sodium bromide and potassium bromide solutions were measured as functions of concentration (0.0085≤m (mol kg⁻¹)≤14.06) and temperature (273.15≤T(K)≤323.15). Allied properties like isentropic compressibilities, effective pressure, classical sound absorption and shear relaxation time were calculated by using the measured data. The interaction in these three bromide solutions vary in the order of NaBr>KBr>LiBr. The primary hydration shells are saturated at 10.8, 5.1 and 5.8 mol kg⁻¹ with 5.1, 10.9 and 9.6 number of water molecules in the primary hydration shell of lithium bromide, sodium bromide and potassium bromide solutions respectively. The cationic environment is found to influence the hydration phenomena of the anion.

The non-Arrhenius temperature dependence of shear relaxation time were analysed by using the Vogel-Tammann-Fulcher (VTF) equation. The concentration dependence of shear relaxation time is different in these three bromide solutions. Such an effect is attributed to the competitive effects of hydrogen bonding, structure forming/breaking effect of ions and the formation of ion pairs.     

A stochastic model for solidification II. Application to binary metallic melts

A stochastic model to study the solidifcation process developed in part I is applied to various binary alloys having different values of interaction energies. The results obtained for the time evolution of temperature and concentration, rate of growth and shape of the solid-liquid interface are presented.     

On some tests of the basic properties of the neutral weak interaction. II. With massive neutrinos

Assuming a general nonderivative point interaction, and Born approximation, the angular distributions for neutrino scatterings by electrons are written, using only simple considerations, allowing all leptons to have nonzero mass. Our distributions have been previously obtained for some special cases, from general considerations by Bell et al., or in the results of explicit calculations. Applications to (i) determination of the Lorentz structure of the neutral weak interaction, and (ii) tests of lepton locality are considered. For illustration, two explicit calculations are given; one of these could hold for heavy lepton production, and the other for scattering of very low energy cosmic neutrinos.     

Effect of Radiofrequency Plasma Assisted Grafting of Polypropylene on the Properties of Muga Silk Yarn

Radiofrequency (RF) Ar/propylene glow discharge is utilized for grafting polypropylene onto muga silk yarn at working pressure of 1.2?×?10^?1 mbar and in the of RF power range of 20?C80?W. The plasma discharge is diagnosed using self-compensated emissive probe to study the variation of ion energy impinging on the substrates with RF power. From chemical compositional analysis, a possible grafting mechanism between propylene and muga yarn is proposed by considering the charge-transfer initiation through the formation of electron-donor?Cacceptor (EDA) complex. X-ray photoelectron spectroscopy reveals that at RF power values of 60?C80?W, the ion sputtering effect becomes dominant over plasma grafting thereby leading to severe destruction in chemical structure of the polypropylene grafted (PP-grafted) muga yarns. The experimental results show that PP-grafted muga yarns exhibit improved mechanical strength and hydrophobic behavior as compared to the virgin yarn. The properties of the PP-grafted muga yarns are observed to be dependent on atomic concentration, surface morphology as well as the results obtained from plasma discharge characteristics.     

Screening dependence of superconducting state parameters

Theoretical values of superconducting state parameters of a number of superconductors are presented here using linear potential with seven different forms of dielectric screening in order to exhibit the dielectric dependence of these parameters. Presently computed results on comparison with the available experimental data show that the R.P.A. screening provides the best explanation of the superconducting state in most of the metals. It has been observed that the use of a non-local pseudopotential is desirable in the case of complex metals like Al, Pb etc.     

Time-reversal invariance-like relations for spin-effects in elastic and inelastic reactions; vector-meson photoproduction versus compton scattering from nucleons

For elastic scattering, relations between spin-effects (for example, the well-known asymmetry-polarization equality) follow from time-reversal invariance. We show that if certain amplitude combinations vanish, there are strikingly similar relations between spin-effects for elastic and also inelastic reactions. This vanishing of amplitude combinations (denoted M-purity) corresponds asymptotically to purely natural or purely unnatural parity in the crossed channel. The M-purity relations hold for spin-configurations much more general than do the corresponding time-reversal invariance relations.The experimental evidence for purely natural parity exchanges in high energy vector meson photoproduction from nucleons is shown to be good for all amplitudes involving nonzero meson helicity, but less conclusive for the zero helicity ones. Using time-reversal invariance and a vector meson-dominance argument, this implies no unnatural parity contributions in high energy Compton scattering from nucleons.Because of this empirical evidence for M-purity in these two processes, a detailed application to spin-effects in Compton scattering and in vector meson photoproduction is made. Some time-reversal invariance relations in Compton scattering resemble the corresponding M-purity relations though the applicability of the two is different, and there are examples where only one of the two exists. Out of our illustrations, the only M-purity relations which change in form due to the extra amplitudes present in the inelastic reaction are the M-purity analogue and extensions of the asymmetry-polarization equality (of Compton scattering) referring to the photon; the change is the appearance of the elements ?⁰⁰ of the vector meson density-matrix ?. Our other examples of M-purity relations do not change in form in going over from the elastic reaction (Compton scattering) to the inelastic reaction (vector meson photoproduction).