Starch - polyvinylalcohol - acetal: A watersoluble film

To ensure more comfort, dosage units of active ingredients may be packed in water soluble film prior to application. In the mean time plasticised polyvinylalcohol (PVAL), with limited metabolitic degradability in common water epuration units, is used for present purpose. In this work we found that the reducing chain ends of degraded starch molecules form semi acetals with the hydroxyl moieties of (PVAL). Reaction conditions could be selected for processing in a twin screw extruder. Due to replacement of around 50% of the polyvinylalcohol by starch the production costs are significantly lower than that of pure PVAL-films. The acetal films show better mechanical properties, seal easier, dissolve faster in water and mineralise at lower temperatures if compared with pure PVAL.     

Energy spectra for decaying 2D turbulence in a bounded domain

We use results derived in the framework of the replica approach to study the liquid-glass thermodynamic transition. The main results are derived without using replicas and applied to the study of the Lennard-Jones binary mixture introduced by Kob and Andersen. We find that there is a phase transition due to the entropy crisis. We compute both analytically and numerically the value of the phase transition point T(K) and the specific heat in the low temperature phase.     

Starch alkanoates as models for thermoplastic polysaccharides

The low degree of internal molecular mobility of stiff polysaccharide chains prevent any thermal transition in the temperature range of their chemical stability. Substituted starches were synthesised to find the structural range, i.e. the necessary amount and length of mobile side chains which support the molecule with high enough level of internal degrees of freedom. Esterification and transesterification with hydroxy alkanoates, their polymers and lactones were used. The reaction was best catalysed with strong delocalised bases. The thermal properties of these model substances were characterised.     

89Y NMR Studies of MBE Grown DyFe2/YFe2 Multilayer Films

Hyperfine Interactions - 89Y (spin I=1/2) NMR studies of DyFe2/YFe2 multilayer films at 4.2 K are reported and discussed. Results are presented for a 1000 Å thick film of YFe2, and a 24,000...     

Complex degree of mutual anisotropy of extracellular matrix of biological tissues

We study the possibility of the differentiation of optical anisotropy properties of biological tissues in different physiological states by means of statistical analysis of coordinate distributions of a new analytical parameter, the complex degree of mutual anisotropy of a network of birefringent filament-like protein crystals.     

Geometric phase contribution to quantum nonequilibrium many-body dynamics

We study the influence of geometry of quantum systems underlying space of states on its quantum many-body dynamics. We observe an interplay between dynamical and topological ingredients of quantum nonequilibrium dynamics revealed by the geometrical structure of the quantum space of states. As a primary example we use the anisotropic XY ring in a transverse magnetic field with an additional time-dependent flux. In particular, if the flux insertion is slow, nonadiabatic transitions in the dynamics are dominated by the dynamical phase. In the opposite limit geometric phase strongly affects transition probabilities. This interplay can lead to a nonequilibrium phase transition between these two regimes. We also analyze the effect of geometric phase on defect generation during crossing a quantum-critical point.     

Volume dependence of NMR of ordered correlated electron systems

The importance of NMR high pressure studies of ordered magnetic materials for the understanding of the ground and excited states of magnetic conductors is discussed with examples from recent work on the manganese perovskites and the rare earth compounds SmMn₂Ge₂ and CeIn₃. A brief discussion is given of the difference between true pressure experiments and the “chemical pressure” introduced by changing the composition of a material. This revised version was published online in July 2006 with corrections to the Cover Date.