A new, gentle enzymatic method was developed for a controlled removal of casein layers from medieval wall paintings. These casein layers were applied over the last 60 years on wall paintings in order to decrease substantial damage due to a peeling off of the frescoes from the roughcast surface due to environmental effects. However, due to the aging of the casein layers (at 40±50 years), a more drastic peeling occurred and the danger of total destruction of the wall paintings is severe. Thus, screening was performed to ®nd the most suitable enzyme for casein digestion. Alcalase 2.5 DX L was the most appropriate enzyme for an effective proteolysis reaction. The enzyme was immobilized on functionalized cellulose membrane. A membrane pad system with immobilized enzymes was developed which could be pressed on the casein layers on the wall painting. A controlled removal of the casein layers by proteolytic digestion was observed and it was possible to continuously wash off the hydrolyzed casein fragments from the wall painting surface by an aqueous carbonate buffer¯owing through the membrane pad. The removal and the digestion was monitored by reverse HPLC. Additionally, an on-line monitoring system was set up in order to continuously follow the casein layer removal and the digestion procedure directly on the wall painting. This technique is based on noninvasive 2D-¯uorescence monitoring. Optical ®ber systems were used to continuously monitor the¯uorescence intensity of casein-bound tryptophan. The off-line data were veri®ed with the on-line 2D-¯uorescence data. Based on the scienti®c result an appropriate technique for the controlled enzymatic removal of damaging casein layers on the surface of medieval wall paintings using immobilized enzyme is now available. It is now applied to remove such casein layers from medieval wall paintings in the Allerheiligen-Kapelle Cloister,

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In decentralized university library systems department libraries act as interfaces between scientists and students that qualifies them to promote information literacy in particular. The following article describes the development of a concept for the promotion of information literacy courses at the Department of Political Science at RWTH Aachen University. The concept, based on the results of a survey among teaching staff, is influenced by accepted standards and guidelines of information literacy skills and it will take didactical requirements into consideration.

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