Nano-star formation in Al-doped ZnO thin film deposited by dip-dry method and its characterization using atomic force microscopy, electron probe microscopy, photoluminescence and laser Raman spectroscopy

Zinc oxide doped with Al (AZO) thin films were prepared on borosilicate glass substrates by dip and dry technique using sodium zincate bath. Effects of doping on the structural and optical properties of ZnO film were investigated by XRD, EPMA, AFM, optical transmittance, PL and Raman spectroscopy. The band gap for ZnO:Al (5.0 at. wt.%) film was found to be 3.29 eV compared with 3.25 eV band gap for pure ZnO film. Doping with Al introduces aggregation of crystallites to form micro-size clusters affecting the smoothness of the film surface. Al³⁺ ion was found to promote chemisorption of oxygen into the film, which in turn affects the roughness of the sample. Six photoluminescence bands were observed at 390, 419, 449, 480, 525 and 574 nm in the emission spectra. Excitation spectra of ZnO film showed bands at 200, 217, 232 and 328 nm, whereas bands at 200, 235, 257 and 267 nm were observed for ZnO:Al film. On the basis of transitions from conduction band or deep donors (CB, Zn_i or V_OZn_i) to valence band and/or deep acceptor states (VB, V_Zn or O_i or O_Zn), a tentative model has been proposed to explain the PL spectra. Doping with Al³⁺ ions reduced the polar character of the film. This has been confirmed from laser Raman studies.     

Limits on an energy dependence of the speed of light from a flare of the active galaxy PKS 2155-304

In the past few decades, several models have predicted an energy dependence of the speed of light in the context of quantum gravity. For cosmological sources such as active galaxies, this minuscule effect can add up to measurable photon-energy dependent time lags. In this Letter a search for such time lags during the High Energy Stereoscopic System observations of the exceptional very high energy flare of the active galaxy PKS 2155-304 on 28 July 2006 is presented. Since no significant time lag is found, lower limits on the energy scale of speed of light modifications are derived.     

Experimental signature of entrance channel effect in heavy mass region via evaporation residue cross section and spin distribution measurements

Evaporation residue (ER) cross sections and gamma multiplicity distributions have been measured for ¹⁶O + ¹⁸⁴W and ¹⁹F + ¹⁸¹Ta systems in the excitation energy range of 50–90 MeV, leading to the same compound nucleus ²⁰⁰Pb^∗. Comparison of experimental results of both the systems shows that ER cross sections and moments of gamma multiplicity distribution of ¹⁶O + ¹⁸⁴W system are significantly higher than those of ¹⁹F + ¹⁸¹Ta system at higher excitation energies. Present measurements directly shows the experimental signature of entrance channel effect even with the systems which are not very different with respect to their entrance channel mass asymmetry. It is further demonstrated that the reduction in the ER cross section and moments of spin distribution for ¹⁹F + ¹⁸¹Ta system is mainly due to the suppression of fusion of higher l values.     

Further results on the Drazin inverse of even‐order tensors

The notion of the Drazin inverse of an even‐order tensors with the Einstein product was introduced, very recently [J. Ji and Y. Wei. Comput. Math. Appl., 75(9), (2018), pp. 3402‐3413]. In this article, we further elaborate this theory by establishing a few characterizations of the Drazin inverse and $\mathrm{??}$‐weighted Drazin inverse of tensors. In addition to these, we compute the Drazin inverse of tensors using different types of generalized inverses and full rank decomposition of tensors. We also address the solution of multilinear systems by using the Drazin inverse and iterative (higher order Gauss‐Seidel) method of tensors. Besides these, the convergence analysis of the iterative technique is also investigated within the framework of the Einstein product.     

Sulfur-Containing Foldamer-Based Artificial Lithium Channels

Unlike many other biologically relevant ions (Na⁺, K⁺, Ca²⁺, Cl⁻, etc) and protons, whose cellular concentrations are closely regulated by highly selective channel proteins, Li⁺ ion is unusual in that its concentration is well tolerated over many orders of magnitude and that no lithium-specific channel proteins have so far been identified. While one naturally evolved primary pathway for Li⁺ ions to traverse across the cell membrane is through sodium channels by competing with Na⁺ ions, highly sought-after artificial lithium-transporting channels remain a major challenge to develop. Here we show that sulfur-containing organic nanotubes derived from intramolecularly H-bonded helically folded aromatic foldamers of 3.6 Å in hollow cavity diameter could facilitate highly selective and efficient transmembrane transport of Li⁺ ions, with high transport selectivity factors of 15.3 and 19.9 over Na⁺ and K⁺ ions, respectively.     

Antioxidant and Hepatoprotective Activity of a Lichen Usnea ghattensis in Vitro

Antioxidative and hepatoprotective activity of a cultured lichen Usnea ghattensis has been studied. The methanolic extract of cultured lichen U. ghattensis showed good antioxidant activity by preventing lipid peroxidation by 67% and 86% in Trolox-equivalent antioxidant capacity at 20 microg/ml. It also showed superoxide, 1,1-diphenyl-2-picrylhydrazyl, nitric oxide, and hydroxyl radical-scavenging activity, 89%, 89.6%, 94.8%, and 89.6%, respectively, and found levels higher then that known for the synthetic antioxidants butylated hydroxytoluene, butylated hydroxyanisol, and quercetin at 20 microg/ml concentration. The cultured lichen extract also showed hepatoprotection against ethanol-induced toxicity in the mice liver slice culture model by a significant decrease in the antioxidant enzymes, glutathione peroxidase, catalase, and superoxide dismutase, along with a decrease in lipid peroxidation and lactate dehydrogenase release.     

Ionic liquid induced changes in the properties of aqueous zwitterionic surfactant solution

Modifying properties of aqueous surfactant solutions by addition of external additives is an important area of research. Unusual properties of ionic liquids (ILs) make them ideal candidates for this purpose. Changes in important physicochemical properties of aqueous zwitterionic N-dodecyl- N, N-dimethyl-3-ammonio-1-propanesulfonate (SB-12) surfactant solution upon addition of hydrophilic IL 1-butyl-3-methylimidazolium tetrafluoroborate, [bmim][BF 4], are reported. Dynamic light scattering results indicate a dramatic reduction in the average micellar size in the presence of [bmim][BF 4]; micellar (or micelle-like) aggregation in the presence of as high as 30 wt % [bmim][BF 4] is confirmed. Responses from fluorescence probes are used to obtain critical micelle concentration (cmc), aggregation number ( N agg), and dipolarity and microfluidity of the micellar pseudophase of aqueous SB-12 in the presence of [bmim][BF 4]. In general, increasing the amount of [bmim][BF 4] to 30 wt % results in decrease in N agg and increase in cmc. Increase in the dipolarity and the microfluidity of the probe cybotactic region within the micellar pseudophase is observed on increasing [bmim][BF 4] concentration in the solution. It is attributed to increased water penetration into the micellar pseudophase as [bmim][BF 4] is added to aqueous SB-12. It is proposed that IL [bmim][BF 4] behaves similar to an electrolyte and/or a cosurfactant when present at low concentrations and as a polar cosolvent when present at high concentrations. Electrostatic attraction between cation of IL and anion of zwitterion, and anion of IL and cation of zwitterion at low concentrations of [bmim][BF 4] is evoked to explain the observed changes. Presence of IL as cosolvent appears to reduce the efficiency of micellization process by reducing the hydrophobic effect.     

Modulating properties of aqueous sodium dodecyl sulfate by adding hydrophobic ionic liquid

Altering and modifying important physicochemical properties of aqueous surfactant solutions is highly desirable as far as potential applications of such systems are concerned. Changes in the properties of aqueous solutions of a common anionic surfactant sodium dodecyl sulfate (SDS) are assessed in the presence of a common and popular 'hydrophobic' ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate (bmimPF(6)). Upon addition of up to approximately 0.10 wt% bmimPF(6), a dramatic decrease in critical micelle concentration (cmc) is accompanied by an increase in the degree of counterion dissociation (alpha) and micellar aggregation number (N(agg)) indicating micellar growth. However, in the range 0.10 wt% < or = bmimPF(6) 2.00 wt%, relatively gradual decrease in alpha and N(agg) is observed along with no change in cmc. Significantly decreased microfluidity of the aqueous SDS solutions on addition of bmimPF(6) is indicated by a fluorescence microviscosity probe 1,3-bis-(1-pyrenyl)propane which suggests partitioning of bmimPF(6) into the SDS micellar phase. Behavior of solvatochromic fluorescence probes, pyrene, pyrene-1-carboxaldehyde, and 2-(p-toluidino)naphthalene-6-sulfonate, confirms interaction, and possible complexation, between IL bmimPF(6) and anionic micellar surface. Increased solubility of bmimPF(6) with increasing SDS concentration further confirms SDS-bmimPF(6) interactions. Presence of strong electrostatic attraction between bmim(+) and anionic micellar surface is proposed to be the most dominant reason for these observations. All-in-all, unique role of a hydrophobic ionic liquid bmimPF(6) in modifying the properties of aqueous anionic sodium dodecyl sulfate is demonstrated.     

Further results on generalized inverses of tensors via the Einstein product

The notion of the Moore–Penrose inverse of tensors with the Einstein product was introduced, very recently. In this paper, we further elaborate on this theory by producing a few characterizations of different generalized inverses of tensors. A new method to compute the Moore–Penrose inverse of tensors is proposed. Reverse order laws for several generalized inverses of tensors are also presented. In addition to these, we discuss general solutions of multilinear systems of tensors using such theory.     

Measurement of B(0)(d)-B_(0)(d) mixing rate from the time evolution of dilepton events at the upsilon(4S)

We report a determination of the B(0)(d)-&B_(0)(d) mixing parameter Deltam(d) based on the time evolution of dilepton yields in Upsilon(4S) decays. The measurement is based on a 5.9 fb(-1) data sample collected by the Belle detector at KEKB. The proper-time difference distributions for same-sign and opposite-sign dilepton events are simultaneously fitted to an expression containing Deltam(d) as a free parameter. Using both muons and electrons, we obtain Deltam(d) = 0.463+/-0.008 (stat)+/-0.016 (syst) ps(-1). This is the first determination of Deltam(d) from time evolution measurements at the Upsilon(4S). We also place limits on possible CPT violations.