The biosynthesis of broussonetines: origin of the carbon skeleton

Broussonetines are glycosidase-inhibitory alkaloids obtained from Broussonetia kazinoki. Feeding experiments using [1-13C]glucose and 13C-NMR spectroscopic studies showed that broussonetines are biosynthesized through routes similar to those of sphingosine and phytosphingosine.     

A remarkable stereoselectivity switching upon solid-state versus solution-phase enantiodifferentiating photocyclodimerization of 2-anthracenecarboxylic acid mediated by native and 3,6-anhydro-γ-cyclodextrins

The enantiodifferentiating [4+4] photocyclodimerization of anthracenecarboxylic acid (AC) mediated by native, mono- and di-3,6-anhydro-γ-cyclodextrins was investigated in both aqueous solution and solid-state. The solid-state photolyses gave inherently disfavored head-to-head photodimers in much higher chemical and optical yields than in the aqueous solution.     

Surface Modification of Fine Particles with a SnO<Subscript>2</Subscript> Film by Using a Polyhedral-Barrel Sputtering System

Fine particles were modified with a thin film of SnO₂ by using a barrel sputtering system that is a dry process. The conditions for the preparation of SnO₂ were studied by reactive sputtering onto a glass plate substrate. The optimal conditions for the preparation of tetragonal SnO₂ were identified as 60% partial oxygen pressure and 1.0 Pa total gas pressure with the substrate at room temperature. Under the optimized conditions, the surfaces of Al flake particles were modified with a thin film of SnO₂. XRD and SEM/EDS analysis of the prepared samples showed that the Al particle surfaces were uniformly modified by a thin film of SnO₂ in all cases. The film thicknesses were 80, 130, and 180 nm at RF outputs of 195, 350, and 490 W. These measured thicknesses coincided with the values estimated from the interference colors of the samples.     

Electrode reaction of zinc ions at a dropping mercury electrode in ammonium sulphate solutions

The electrode reaction of Zn(II) at a DME in aqueous solutions of (NH₄)₂SO₄ has been studied by d.c. and square-wave polarography at 25.0±0.1°C. The electrochemical kinetic parameters for the reaction are determined. The appearance of the second wave in the square-wave polarogram has been attributed to the low values of the rate parameter and the transfer coefficient.