Speciation of silica in high-purity water

A 1-l water sample was concentrated to 20ml by freezing and analyzed for soluble, colloidal and insoluble silica by the spectrophotometric heteropoly blue method and by inductively coupled plasma/atomic emission spectrometry. High-purity water obtained from a vitreous-silica sub-boiling distillation still contained a few micrograms of insoluble silica per liter.     

High-performance gel filtration of water-soluble samples on polyvinyl alcohol columns

The chromatographic behaviour in aqueous solution of pullulans, polyethylene glycols, peptides and proteins with different molecular weights on newly developed polyvinyl alcohol columns (Asahipak GS column series: GS-310, GS-320, GS-510 and GS-520) has been investigated. Pullulans and polyethylene glycols eluted according to the gel filtration mode, so both series of compounds produced almost equal calibration curves for GS-310 and GS-320 and for GS-510 and GS-520; the exclusion limits on GS-310 and GS-320 and on GS-510 and GS-520 were found to be ca. 40,000 and 300,000, respectively. Peptides and proteins were found to adsorb slightly on the columns. However, the plots of the elution volumes against the logarithm of the molecular weights for many of the substrates tested gave rise to the linear calibration curves. Recovery of several crude proteins was also studied for the columns and high values were obtained (81–100%). The effects of changes in the flow-rate, temperature and concentration of electrolytes added to the eluents, on the retention of all four types of compound are also reported.     

Organocatalytic asymmetric direct alkylation of alpha-diazoester via C-H bond cleavage

A new variant of phosphoric acid-catalyzed C-C bond forming reaction, direct alkylation of alpha-diazoester, via C-H bond cleavage is presented. The resulting products, beta-amino-alpha-diazoesters, are highly functionalized and useful synthetic precursors for various types of beta-amino acids.     

Multiparticle production in pTa interactions at 8 GeV/c

pTa interactions have been studied. The total inelastic cross section, multiplicities, net charge distributions and inclusive momentum and rapidity spectra for produced particles are reported. The correlations between fast and slow particles are presented and the reaction mechanisms for multiparticle production in pTa interactions are discussed.     

Caesium-selective PVC membrane electrodes based on bis(crown ether)s

Caesium-selective PVC membrane electrodes based on bis(crown ether)s containing benzo-18-crown-6 moieties were prepared using two kinds of plasticizers. Selectivity coefficients for various interfering monovalent ions were determined by the mixed solution method, and were found to relfect the complexing property and extractability of the bis-(benzo-18-crown-6)s. The electrochemical selectivity was also compared with that of the corresponding monocyclic analog and valinomycin.     

4.6-dimethyl-7-hydroxy-nonan-3-one,a sex pheromone of the cigarette beetle (Lasioderma serricorne F.)

A structure of the sex pheromone produced by the female cigarette beetle (Lasioderma serricorne F.) is established as 4,6-dimethyl-7-hydroxy-nonan-3-one (Ia) by chemical and spectroscopic evidences.