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Trypsins were crystallized by using membrane crystallization techniques, both in static and dynamic configurations. Crystal size distribution analysis revealed the high uniformity in size of the products that is achievable. Crystals produced by using membrane crystallization methods are more uniform than those obtained in conventional batch experiments. Crystals produced in forced solution flow are even more uniform than those obtained in a quiescent membrane system. Typical values obtained of percent standard deviation and Span are comparable to or even better than those reported in the literature. Crystal growth rate is favorably affected by solution convective motions in forced solution flow, by increasing solution velocity up to a maximum, which, in the best case, has been observed to be ca. 1500 μm/s. These high values of suitable velocities are characteristics of the membrane system; as with traditional method, growth rate deceleration was already visible at 250 μm/s. The maximum seems to be shifted according to the kinematic viscosity of the crystallizing solutions. Some crystals were assessed by X-ray crystallographic analysis, which demonstrated that dynamically grown crystals show no loss in diffraction quality with respect to static membrane crystallized proteins.

Switchable nematic emulsions are dispersions of micron-sized liquid crystal droplets in a monomer matrix, which can be switched from an opaque OFF state to a transparent ON state by application of very low electric fields. In this paper, we present our preliminary results concerning the behavior of switchable nematic emulsions operating in a reverse mode, that is, droplets characterized by a transparent OFF state that can be electrically turned into an opaque ON state. Radial droplets of liquid crystal with a negative dielectric anisotropy have been prepared with a well-defined transparent state by choosing a monomer mixture that matched the average refractive index of the liquid crystal droplets. The application of an electric field determines the reorientation of liquid crystal directors through an elastic distortion and the achievement of a more scattering state. The effect of temperature on the electro-optical response is also reported.