Preselection and expert advice

We study the effects of preselection on an expert’s advice about the execution of a project if its execution yields more precise estimates about the expert’s expertise. The introduction of a preselection stage, in which the decision maker evaluates the project before asking for advice, alters the expert’s perception of the problem. We identify conditions under which preselection occurs in equilibrium. We show that if the expert adjusts his behavior, the option to preselect may reduce the expected utility of the decision maker.     

Convergence to a propagating front in a degenerate Fisher-KPP equation with advection

We consider a Fisher-KPP equation with density-dependent diffusion and advection, arising from a chemotaxis–growth model. We study its behavior as a small parameter, related to the thickness of a diffuse interface, tends to zero. We analyze, for small times, the emergence of transition layers induced by a balance between reaction and drift effects. Then we investigate the propagation of the layers. Convergence to a free boundary limit problem is proved and a sharp estimate of the thickness of the layers is provided.     

Use of supercritical CO2‐aided and conventional melt extrusion for enhancing the dissolution rate of an active pharmaceutical ingredient

Dispersing at the molecular level a drug in a polymer matrix is a major challenge to be addressed by the pharmaceutical industry to enhance its bioavailability or to control its release. Melt extrusion and supercritical CO₂‐aided melt extrusion of solid pharmaceutical formulations were performed to enhance the dissolution rate of carvedilol, taken as a model of poorly soluble drug. The presence of the drug improved the processability of the polyacrylate matrix (Eudragit E) through its plasticizing effect. The supercritical method was found gentle compared with melt extrusion owing to the shorter residence time and lower processing temperature and melt viscosity. No traces of decomposition of the drug could be detected after the supercritical extrusion process based on capillary electrophoresis results. This extrusion process resulted in effective homogenization of the components and amorphization of the drug according to Raman mapping, Fourier transform infrared spectrometry, X‐ray diffraction, and polarized light microscopy. The kinetics of dissolution can be dramatically improved. Copyright © 2011 John Wiley & Sons, Ltd.