Spatial and geometrical control of silicification using a patterned poly-l-lysine template

A simple process to achieve patterned silica films is described. The patterning of the catalyst poly-l-lysine via photolithography and liftoff enables the spatial and geometrical control of silicification. Microscopy and chemical characterization demonstrate that this process enables consistent patterning of silica with 10 μm resolution in a variety of geometries. In addition, the spatial and geometrical control of the silica is demonstrated under different reaction conditions and yields various silica morphologies. The ability to simultaneously pattern bio-inspired silica and control its morphology may allow the tailoring of silica and other silicon-based materials for future applications.     

Characterising Semi-Cohesive Powders using angle of repose

When properly measured and interpreted angle of repose (AOR) can be a useful method of characterising a powder. Unfortunately, a multitude of definitions and measuring equipment is used. A review of the inherent problems is presented in the first part of this paper. The second part of the paper describes the improvements made to a measuring device developed originally for measuring the angle of repose of soda ash, so that a wider range of powders can be tested. In the improved design, the tendency of cohesive and semi-cohesive powders to block the device's funnel has been eliminated. A total of 73 powders consisting of four different materials, and covering Groups A, A/C and C of Geldart's classification, have been tested using the new equipment. The results show that AOR increases systematically with decrease in mean particle size. Combination of AOR measured in the new device with aerated bulk density provides a quick, sensitive and effective method for characterising a wide range of powders.     

Resolution and assignement of absolute configuration to the (+)- and (−)-cis and trans 3,4-diol metabolites of the anti-juvenile hormone precocene I

The cis and trans 3,4-diol metabolites of precocene I have been prepared inoptically pure form and their absolute configurations have been assigned by independent nmr and CD techniques.