Paclitaxel is an antineoplastic agent derived from the bark of the Pacific Yew Tree (Taxus brevifolia). Oral administration of the pure drug is problematic as it has a poor absorption due to its poor solubility in aqueous media. A specific water-soluble prodrug - PP7 - has been introduced by coupling the drug with a water-soluble polymer. For any kind of medical application and administration, knowledge of the binary isobaric phase-diagram is important since it gives information about solubility, phase transitions and the corresponding compositions. The system PP7 + H2O was studied calorimetrically from -20°C and shows the typical behaviour of an eutectic system. The properties of the phase diagram are discussed in view of other solution properties of the system presented earlier.

The hydrophobic anti‐cancer drug paclitaxel was modified with the hydrophilic poly(ethylene oxide) to a water‐soluble predrug. The modification of the polymer chain results in a different solution behaviour of the macromolecules compared with the unmodified polymer. The phase diagram of the (quasi)binary system predrug‐water was investigated, and molecular simulations of the predrug were executed in vacuum and in the presence of water. The results are important for further engineering on active drug systems.

In this paper some evidence is reported for the change of the bending modulus of a hollow tube oscillator, filled with a solution, during the gelation of the mixture which makes exact density measurements impossible.The principle of the method to measure densities with a density oscillator was founded by Kratky, Leopold and Stabinger'**). It depends on the stimulation of the resonance frequency of a U-shaped quartz tube. If the tube is filled with a fluid, the resonance frequency is a function of the density of the fluid at constant pressure and temperature. The time t for one period of oscillation is given by Eq. (1): where m and V are the mass and the inner volume of the oscillator tube, respectively, and p is the density of the fluid inside the tube; k is the elastic constant of the oscillator. If t is measured for two different fluid substances (indices 1 and 2) with known density, a constant A can be calculated from Eq. (1)under the assumption that the densities are not very differentwhich is given by:It is known that A depends on the temperature. The density p, of an unknown substance is obtained from Eq. (3): 1;t;with i = 1, 2. It is the advantage of this method that the density of fluids can be determined with high precision which corresponds to & 1,s * g . ~m -~. The temperature dependence of the elastic coefficient can be reduced by measuring densities in a reference mode using two oscillators, one of which is filled by a liquid of known density, the other one with the liquid of unknown density. Because of the high accuracy the time dependence of the density of gelatin solutions with concentrations above the critical one for gel formation was measured. The gelatin was a pig skin gelatin, that has been freed from low-molecular-weight compounds by dialysis. For these investigations the system DMA 60/DMA 602 from A. E a r , Graz,

ScalaLab and GroovyLab are both MATLAB-like environments for the Java Virtual Machine. ScalaLab is based on the Scala programming language and GroovyLab is based on the Groovy programming language. They present similar user interfaces and functionality to the user. They also share the same set of Java scientific libraries and of native code libraries. From the programmer's point of view though, they have significant differences. This paper compares some aspects of the two environments and highlights some of the strengths and weaknesses of Scala versus Groovy for scientific computing. The discussion also examines some aspects of the dilemma of using dynamic typing versus static typing for scientific programming. The performance of the Java platform is continuously improved at a fast pace. Today Java can effectively support demanding high-performance computing and scales well on multicore platforms. Thus, both systems can challenge the performance of the traditional C/C++/Fortran scientific code with an easier to use and more productive programming environment.

When liquid droplets touch a sufficiently hot surface the Leidenfrost effect leads to levitation of the droplets on a steam layer. At the same time the heat flux from hot surface to droplet is strongly reduced and the droplet lifetime is increased. The understanding of this effect, which can readily be observed on a standard stove, requires knowledge of fluid dynamics, basic mechanics and thermodynamics. It therefore combines appealing experiments with interdisciplinary physics and is well-suited for teaching physical principles, experimentation, modelling and data analysis in schools and in the early stages of university physics. The aim of this work is to present some guidance for projects in this area. Video analysis was used to quantitatively measure droplet sizes and lifetimes of water and liquid nitrogen droplets placed on a hot plate. A simple model for a levitating droplet was developed and compared to the data. The findings indicate that video analysis is a suitable way to examine the Leidenfrost effect for droplet diameters between about 3 and 10 mm. From the analysis the effective thermal conductivities of the steam layers were determined and were found to be two to three orders of magnitude smaller than the thermal conductivities of the corresponding gases at rest. By measuring several different droplets under varying parameters it was concluded that the precision of the experimental setup is sufficient to provide a practical tool for pupils and undergraduate students to explore this fascinating everyday phenomenon.