A short,highly efficient synthesis of coenzyme Q(10)

The most efficient synthesis reported to date of ubiquinone (CoQ10) is described. A sequence consisting of six operations is involved which leads to crystalline material in an overall yield of >64%.     

Fine hexaferrite particles for perpendicular recording prepared by the coprecipitation method in the presence of an inert component

The modified coprecipitation method has been shown to be suitable for preparing BaFe_2y−2χCo_χTi_χO₁₉ powder with narrow particle size distribution (50–80 nm). The phase composition of the intermediate products during the synthesis has been investigated by DTA, TG, X-ray analysis and Mössbauer spectroscopy. The dependence of the dc measured specific magnetization and coercivity on the Ti-Co content and annealing temperature is presented.     

On shortest cocycle covers of graphs

A cocycle (resp. cycle) cover of a graph G is a family C of cocycles (resp. cycles) of G such that each edge of G belongs to at least one member of C. The length of C is the sum of the cardinalities of its members. While it is known (see [5, 6]) that every bridgeless graph G = (V, E) has a cycle cover of length not greater than $\text{5}\text{3}\text{|E|}$, it is shown that there exists no α < 2 such that every loopless graph G = (V, E) has a cocycle cover with length not greater than α |E|. To do this, cocycle covers of minimal length are determined for the complete graphs, thus solving a problem stated at the end of [6].     

A multilevel characteristics method for periodic convection‐dominated diffusion problems

In this article we introduce a multilevel method in space and time for the approximation of a convection‐diffusion equation. The spatial discretization is of pseudo‐spectral Fourier type, while the time discretization relies on the characteristics method. The approximate solution is obtained as the sum of two components that are advanced in time using different time‐steps. In particular, this requires the introduction of two sets of discretized characteristics curves and of two interpolation operators. We investigate the stability of the scheme and derive some error estimates. They indicate that the high‐frequency term can be integrated with a larger time‐step. Numerical experiments illustrate the gain in computing time due to the multilevel strategy. © 2000 John Wiley & Sons, Inc. Numer Methods Partial Differential Eq 16: 107–132, 2000     

Tricarboranyl pentaerythritol-based building block

A new tricarborane building block based on pentaerythritol was prepared for applications in boron neutron capture therapy (BNCT). Its X-ray single-crystal structure revealed a high degree of steric congestion. To enable the attachment of the building block to other moieties, a succinimidyl linker has been introduced at the focal point, and a generation-2 hexacarborane-containing dendron carrying 60 boron atoms has been prepared using a 2,2-bis(hydroxymethyl)propionic acid core.     

On domination numbers of Cartesian product of paths

We show the link between the existence of perfect Lee codes and minimum dominating sets of Cartesian products of paths and cycles. From the existence of such a code we deduce the asymptotical values of the domination numbers of these graphs.