Fluid adsorption near an apex: covariance between complete and critical wetting

Critical wetting is an elusive phenomenon for solid-fluid interfaces. Using interfacial models we show that the diverging length scales, which characterize complete wetting at an apex, precisely mimic critical wetting with the apex angle behaving as the contact angle. Transfer matrix, renormalization group, and mean-field analysis show that this covariance is obeyed in 2D and 3D and for long- and short-ranged forces. This connection should be experimentally accessible and provides a means of checking theoretical predictions for critical wetting.     

Synthesis and cytotoxicity of novel sansalvamide A derivatives

Described are the syntheses of 14 derivatives of the natural product Sansalvamide A, where two are more active against HCT 116 colon cancer cell lines than the natural product. These derivatives were synthesized using a combinatorial-type strategy that permits elucidation of the amino acid role in the cytotoxicity, and they lay the groundwork for development of new anticancer agents. [structure: see text]     

Warble in carillon bells: An investigation using neutron diffraction

It is speculated that warble in carillon bells can be caused by mode splitting as a result of internal strains produced by non-uniform cooling during casting. The neutron diffraction technique makes possible the measurement of internal strain and is here applied to a in (166 mm) carillon bell with a pronounced 3 Hz warble. Internal strain variations with a 180° periodicity about the bell circumference were detected. From symmetry considerations this periodicity requires that all partials (other than m = 0) should have their doublets split. Measurements of the bell partials confirmed this splitting. The metallographic phases present in the bell metal were also determined and found to agree with expectations.     

What controls the thickness of wetting layers near bulk criticality?

We study the thickness of wetting layers in the binary-liquid mixture cyclohexane methanol. Far from the bulk critical point, the wetting layer thickness is independent of temperature, resulting from the competition between van der Waals and gravitational forces. Upon approaching the bulk critical temperature [t=(T(c)-T)/T(c)-->0], we observe that the wetting layer thickness diverges as t(-beta) with effective critical exponent beta=0.23+/-0.06. This is characteristic of a broad, intermediate scaling regime for the crossover from van der Waals wetting to critical scaling. We predict beta=beta/3 approximately 0.11, with beta the usual bulk-order parameter critical exponent, showing a small but significant difference with experiment.     

Effects of chlorinated aliphatic hydrocarbons on the fidelity of cell division in human CYP2E1 expressing cells

Chlorinated organic chemicals are widely used in industry and are present in the environment. Five chlorinated aliphatic hydrocarbons, namely 1-2-dichloroethane, 1,1,2-trichloroethane, trichloroethylene, 2,3-dichlorobutane and 1-chlorohexane were investigated to determine their influence upon the fidelity of cell division in cultured mammalian cells. In order to determine the influence of these chemical compounds upon the fidelity of cell division, a technique known as differential staining of chromosomes and spindle was performed with one genetically engineered cell line and its parental cell line. The genetically engineered cell line used in this study expressed a human P450 enzyme, CYP2E1. Four chemicals, 1-2-dichloroethane, trichloroethylene, 2,3-dichlorobutane and 1-chlorohexane required metabolic bioactivations in order to induce spindle damage in cultured mammalian cells whereas 1,1,2-trichloroethane was a direct-acting spindle poison.     

Dual attenuation of X-rays for measurement of the concentration of metals in solution

This study examines the feasibility of dual energy attenuation metering to measure the concentration of two elements in aqueous solution, in a pipe of fixed thickness. Photon energies between 20 and 30 keV were selected in order to be able to determine mg L(-1) metal concentrations. Pairs of elements from a group with atomic numbers between 24-82 (Cr, Cu, Zn, Hg and Pb) were used to test the methodology. The sensitivity of measurement for a mixture of two elements was predicted from the ratios of the attenuation coefficients at 20 keV to the ratios at 30 keV. Experimental results confirmed that the sensitivity was greatest for the mixture of Cr and Pb, since those elements have the largest ratio of attenuation coefficients (1.108) and it was possible to accurately analyse a solution containing 0.15 g L(-1) of Cr and 0.13 g L(-1) of Pb. Other pairs of elements with ratios at 1.074 and 1.078 (Cu/Pb, Cu/Hg,) could only be determined at g L(-1) concentrations. It was not possible to differentiate between the pairs of elements with attenuation coefficient ratios below 1.03 (Cr/Zn and Cr/Cu) in this study.     

Determination by enantioselective synthesis of the absolute configuration of CPE, a potential intermediate in coronatine biosynthesis

The first enantioselective synthesis of the methyl ester of CPE, a potential intermediate in coronatine (COR) biosynthesis, is described. Comparison of the specific rotation of the synthetic ester with that of the methyl ester of natural CPE established that the latter possesses the (R) configuration. This configuration is the same as that found at the corresponding asymmetric center of coronatine. Structure: see text.