Wetting behaviour of 5CB and 8CB and their binary mixtures above the isotropic transition

High resolution optical microscopy techniques have been employed to study the wetting properties of (5CB)_x/(8CB)_100-x (x=0, 10, 30, 50, 70, 90, and 100 wt %) binary mixture liquid crystal thin films above the isotropic transitions. Dewetting is found to occurr at T_w=65 and 42.5°C for the 5CB and 8CB samples, respectively, and to depend strongly on the 5CB content in the mixtures. First-order wetting transitions were seen for pure 5CB and 8CB samples; a higher order wetting transitions were obtained for the mixtures. For thin film 5CB, a large hysteresis (ΔT=30°C) between wetting and dewetting during the heating and cooling is obtained. This hysteresis is compared with the corresponding values obtained for pure 8CB and mixture samples. Evidence of the formation of nematic layers on the surface of isotropic droplets was found. Attempts to extract values of the contact line tension for these materials are made. In this respect the applicability of the modified Young's equation is questionable.     

Normal coordinate treatment and assignment of fundamental vibrations of vinyl fluoride and the seven deuterovinyl fluorides

The results of a unified normal coordinate treatment for vinyl fluoride and the seven deuterated species are presented. Our calculation confirms the out-of-plane assignment of Scherer and Potts. For the in-plane vibrations, we have used a modified valence-force type of potential function and, on the basis of the results, we are presenting a satisfactory assignment for most of the fundamentals. Investigation of the liquid spectra is recommended to resolve the ambiguity of the remaining few undecided in-plane fundamentals.The authors wish to thank both the Data Processing Center of Texas A & M University for the generous allotment of computer time during the early part of this investigation and the Bartlesville Petroleum Research Center of the Bureau of Mines for the key punch facilities during the latter part of this research. Thanks are also due Dr. Donald W. Scott of the Bartlesville Petroleum Research Center for stimulating discussions. This work was supported in part by the Thermodynamics Research Center Data Project (formerly the Manufacturing Chemists Association Research Project) and the National Bureau of Standards Office of Standard Reference Data.     

Modeling of tsunami generation and propagation by a spreading curvilinear seismic faulting in linearized shallow-water wave theory

The processes of tsunami evolution during its generation in search for possible amplification mechanisms resulting from unilateral spreading of the sea floor uplift is investigated. We study the nature of the tsunami build up and propagation during and after realistic curvilinear source models represented by a slowly uplift faulting and a spreading slip-fault model. The models are used to study the tsunami amplitude amplification as a function of the spreading velocity and rise time. Tsunami waveforms within the frame of the linearized shallow-water theory for constant water depth are analyzed analytically by transform methods (Laplace in time and Fourier in space) for the movable source models. We analyzed the normalized peak amplitude as a function of the propagated uplift length, width and the average depth of the ocean along the propagation path.     

Lie‐group method for solving the problem of fission product behavior in nuclear fuel

Calculation of the gas atom concentration is an important feature of all physical models of fission gas release. We apply Lie‐group method for determining symmetry reductions to the diffusion equation describing the fission gas release from nuclear fuel. The resulting nonlinear ordinary differential equation is solved numerically using nonlinear finite difference method. Effects of the dimensionless group constant, the time, and the grain radius on the concentration diffusion function have been studied, and the results are plotted. It is found that the concentration of gas atoms increases as the dimensionless group constant, the power index, and the time increase, and it decreases with increase of the grain radius. Copyright © 2013 John Wiley & Sons, Ltd.     

On the singularities of multiple L-functions

We investigate the singularities of a class of multiple L-functions considered by Akiyama and Ishikawa [2].     

Application of 8-hydroxyquinoline-5-sulfonic acid in the spectrophotometric determination of some lanthanides

A simple, sensitive, and selective spectrophotometric method for the determination of trivalent praseodymium, neodymium, samarium, gadolinium, dysprosium, and erbium ions with 8-hydroxyquinoline-5-sulfonic acid is described. The optimum conditions for determination of down to 10.0 μg/ml of lanthanide ion are reported. The proposed method shows an average recovery of 99.9% with standard deviation not exceeding 0.1%. The metal-ligand ratio and stability constant of the chelates are determined.     

Fluorinated hydrazonoyl chlorides as precursors for synthesis of antimicrobial azoles

Hydrazonoyl halides have been known for their ability to react with different reagents to afford wide range of bioactive heterocyclic systems as thiazoles and imidazopyrazoles. This research work focused on the synthesis of two new fluorinated hydrazonoyl chlorides and used them in synthesis of novel series of thiazole derivatives and two imidazopyrazole systems. The mechanistic pathways and the structures of all synthesized derivatives were discussed and assured based on the available spectral data. The results of antimicrobial activity of the tested thiazoles and imidazopyrazoles showed that some derivatives have moderate to no activity against tested fungi and bacteria strains. Only one derivative namely 2-(2-(3-fluoro-4-methylphenyl)hydrazono)-7-(2-oxoindolin-3-ylidene)-2,7-dihydro-3H-imidazo[1,2-b]pyrazole-3,6(5H)-dione is the most active against Candida albicans (CA) with IZD = 20 mm, which was equipotent to ketoconazole. Furthermore, docking simulation was carried out to predict the binding pattern of the new compounds in the ATP binding site of the DNA gyrase B enzyme. The results of the docking simulation revealed that compounds 9a-e , 12 , and 13a,b fit well in the ATP binding site of DNA gyrase B with docking score values ranging from −5.883 to −6.833 kcal/mol.     

Preparation and characterization of polyaniline/manganese dioxide composites and their catalytic activity

This paper is devoted to the preparation of polyaniline/MnO2 (PANI/MnO2) composites via chemical oxidation of aniline in H2SO4 medium using beta-MnO2 as an oxidant. The parameters affecting the polymerization reaction are considered. These parameters are [aniline], amount of beta-MnO2, stirring time, and polymerization temperature. SEM, FT-IR, XRD, and TGA techniques are used to characterize the resulting composites. XRD measurements reveal the distortion of the crystal structure of beta-MnO2 after the polymerization reaction. Thus, the XRD pattern of PANI is predominating. The crystalline composites are obtained using higher molar ratio of [Ox]/[ANI] and at higher temperature. Increasing the amount of beta-MnO2 led to an increase in the acidic character of the obtained composites due to adsorption of excess H+ on the oxide surface. The thermal stability of the composites decreased with increasing both [aniline] and stirring time, while it increased with increasing amount of beta-MnO2. The applications of the composites in the oxidative degradation of Direct Red 81, Acid Blue 92, and Indigo Carmine dyes exhibited good catalytic activity in the presence of H2O2 as an oxidant. The reactions followed first-order kinetics and the rate constants were determined. The degradation reaction involved the catalytic action of the PANI counterpart of the composite toward H2O2 decomposition, which can lead to the generation of HO radicals as a highly efficient oxidant attacking the target dyes. The detailed kinetic studies and the mechanism of these catalytic reactions are under consideration in our group.     

Nanocarriers for cytoplasmic delivery: cellular uptake and intracellular fate of chitosan and hyaluronic acid-coated chitosan nanoparticles in a phagocytic cell model

The cellular uptake of hyaluronic-acid-coated, negatively charged chitosan/triphosphate nanoparticles and that of uncoated, positively charged ones is investigated by studying cellular localization, uptake kinetics and mechanism of internalization in J774.2 macrophages, using non-phagocytic L929 fibroblasts as a control for uncoated nanoparticles. Both kinds of nanoparticles undergo endosomal escape and adopt a similar clathrin-based endocytic mechanism. The surface decoration with HA profoundly influences the kinetics of cellular uptake, with an at least two orders of magnitude slower kinetics, but also the nature of the binding on the cellular surface.