There is currently considerable interest in using mainly solid reaction mixtures for enzymic catalysis. In these reactions starting materials dissolve into, and product materials crystalize out of, a small amount of liquid phase in which the catalytic reaction occurs. An initial mathematical model for mass transfer effects in such systems is constructed using some physically reasonable approximations. The model equations are solved numerically to determine how the reactant concentrations vary with time and position. To evaluate the extent to which mass transfer limits the overall rate of product formation, an effectiveness factor is defined as the ratio of the observed total reaction rate to the total reaction rate in the reaction limited limit. As expected, the value of the effectiveness factor in steady state is strongly dependent on the Thiele modulus. However, it is also observed that the effectiveness factor can vary widely as a result of changes in the other dimensionless groups characterizing the system. For example, there are situations with Thiele modulus equal to unity in which the value of the effectiveness factor varies between approximately 0.1 and 0.8 as the other parameters are varied in physically reasonable ranges. Analytical asymptotic solutions that provide good approximations to the numerically calculated results in various physically important limiting cases are also presented.

A uniform and comprehensive terminology is essential in the correct documentation of diagnostic or therapeutic endoscopic procedure. In the German-speaking world, the standard terminology available so far is based on a previous version published in 1999. Therefore, the German Society for Gastroenterology, Digestive and Metabolic Diseases (DGVS) has undergone a comprehensive revision and re-structuring of the terminology. This appeared mandatory due to various changes, new diagnoses and new endoscopic procedures. The suggestions drawn up by individual working groups were approved by consensus and are now available as an online document (https://doi.org/10.1055/s-0043-121167) for modifying current software systems. In order to ensure an up-to-date documentation in the future, it was decided that annual updates will be performed by the DGVS to check respective software packages for modifications and new contents.