Solid state dehydration processes: mechanism of water loss from crystalline inosine dihydrate

The solid state dehydration of inosine dihydrate has been investigated using powder X-ray diffraction, differential scanning calorimetry, thermal gravimetric analysis, dynamic vapor sorption, hot stage microscopy, 13C solid state NMR, and variable temperature Fourier transform infrared spectroscopy. The information obtained from these experiments has been combined with an analysis of the crystallographic packing of inosine dihydrate and its two anhydrous polymorphs to yield mechanistic insights into the modes of water loss. The results allow an understanding of why, surprisingly, the dehydration of the dihydrate is always found to give the anhydrous, metastable, alpha-form.     

Viability of plant cell suspensions exposed to homogeneous ultrasonic fields of different energy density and wave type

Exposure of Petunia hybrida cell suspensions to ultrasound at a frequency of 2.43 MHz in a standing wave field at an energy density of 70 Jm-3 (pressure amplitude of 0.78 MPa) decreased their mean viability to 35% after 20 min of sonication. A comparison of propagating wave and standing wave treatments at equal frequency (2.15 MHz) and energy density (8.5 Jm-3) showed, in the first case, a rapid decline in mean viability of cells (to 30% after 10 min of sonication) and, in the second case, a retaining of the initial viability (95%), respectively. Cells sonicated 4 days after subculture were more sensitive than cells sonicated 2 or 6 days after transfer to new culture medium. It was concluded that cellular viability depends primarily on the acoustic energy density, the exposure time, and the mechanical properties of the cells determined by age. As a consequence of the trapping of cells in the anti-node planes of the standing wave, propagating wave fields reduced cellular viability compared with standing wave fields at equal energy density.     

Binary homomorphisms and natural dualities

We investigate ways in which certain binary homomorphisms of a finite algebra can guarantee its dualisability. Of particular interest are those binary homomorphisms which are lattice, flat-semilattice or group operations. We prove that a finite algebra which has a pair of lattice operations amongst its binary homomorphisms is dualisable. As an application of this result, we find that every finite unary algebra can be embedded into a dualisable algebra. We develop some general tools which we use to prove the dualisability of a large number of unary algebras. For example, we show that the endomorphisms of a finite cyclic group are the operations of a dualisable unary algebra.     

Laser desorption sources and time-of-flight injection for RFQ traps

Pulsed laser desorption sources are well suited to the production of ions to be stored in Paul radio-frequency quadrupole traps. With external injection, ions of different masses may be cleanly separated by time-of-flight and efficiently captured. Resonant ionization techniques may be used at the source for element selection.     

From the subalgebras of the square to the discriminator

Presented by A. F. Pixley.     

Guaranteed error bounds for the initial value problem using polytope arithmetic

In this paper we propose and compare modifications of the method of co-ordinate transformations for finding guaranteed bounds for the numerical solution of the initial value problem. These modifications are judged on their success in overcoming exponentially too large growth of the computed error bound.     

Highly efficient liquid-phase oxidation of primary alcohols to aldehydes with oxygen catalysed by Ru-Co oxide

RuIV-CoIII (1:1.5) binary oxide, prepared by co-precipitation, is a highly efficient solid catalyst for the oxidation of primary alcohols to aldehydes with O2 (76-95% selectivity at 54-100% conversion) in a liquid phase under atmospheric pressure.