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Pumps are mainly used when transferring sterile culture broths in biopharmaceutical and biotechnological production processes. However, during the pumping process shear forces occur which can lead to qualitative and/or quantitative product loss. To calculate the mechanical stress with limited experimental expense, an oil-water emulsion system was used, whose suitability was demonstrated for drop size detections in bioreactors 1 . As drop breakup of the oil-water emulsion system is a function of mechanical stress, drop sizes need to be counted over the experimental time of shear stress investigations. In previous studies, the inline endoscopy has been shown to be an accurate and reliable measurement technique for drop size detections in liquid/liquid dispersions. The aim of this protocol is to show the suitability of the inline endoscopy technique for drop size measurements in pumping processes. In order to express the drop size, the Sauter mean diameter d 32 was used as the representative diameter of drops in the oil-water emulsion. The results showed low variation in the Sauter mean diameters, which were quantified by standard deviations of below 15%, indicating the reliability of the measurement technique.

Pumps are mainly used when transferring sterile culture broths in biopharmaceutical and biotechnological production processes. However, during the pumping process shear forces occur which can lead to qualitative and/or quantitative product loss. To calculate the mechanical stress with limited experimental expense, an oil-water emulsion system was used, whose suitability was demonstrated for drop size detections in bioreactors 1 . As drop breakup of the oil-water emulsion system is a function of mechanical stress, drop sizes need to be counted over the experimental time of shear stress investigations. In previous studies, the inline endoscopy has been shown to be an accurate and reliable measurement technique for drop size detections in liquid/liquid dispersions. The aim of this protocol is to show the suitability of the inline endoscopy technique for drop size measurements in pumping processes. In order to express the drop size, the Sauter mean diameter d 32 was used as the representative diameter of drops in the oil-water emulsion. The results showed low variation in the Sauter mean diameters, which were quantified by standard deviations of below 15%, indicating the reliability of the measurement technique. Video LinkThe video component of this article can be found at

Since early 1990, discussions concerning the continued publication of the Marx-Engels-Gesamtausgabe (MEGA) have been held in Amsterdam, Berlin and Moscow. They have involved representatives of the International Institute of Social History (IISH) in Amsterdam, the Institute of Marxism-Leninism of the Central Committee of the Communist Party of the Soviet Union (IML) in Moscow, the Academy of Sciences of the German Democratic Republic (AdW) in Berlin and the Karl Marx House of the Friedrich Ebert Foundation (KMH) in Trier. There was agreement that, in view of the status of the ideas of Karl Marx and Friedrich Engels in the history of social science and the impact their ideas have had on world events, the publication of a complete critical edition of their collected works, manuscripts and correspondence must remain a priority for international research. It was agreed that the IISH (which possesses the largest part of the Marx-Engels papers), the IML (which possesses a smaller part), the AdW and the KMH would make joint efforts to ensure that the publication of the MEGA is continued. To this end, the International Marx-Engels Foundation (IMEF) was set up on 2 October 1990. Based in Amsterdam, it will henceforward act as the publisher of the MEGA. The board of the IMEF includes a representative from each of the founding institutions: E. J. Fischer (IISH), M. P. Mchedlov (IML), H. Pelger (KMH) and W. Schmidt (AdW). At its constituent meeting on 2 November 1990 in Amsterdam, the board decided, among other things, to: (a) establish a secretariat at the IISH under the direction of J. Rojahn; (b) establish an international editorial commission, which will eventually number ten to twelve members, but will initially consist of B. A. Bagaturiya (IML), J. Grandjonc (KMH), M. Hundt (AdW) and J. Rojahn (IISH); and (c) convene an international advisory board consisting of leading specialists in the field.

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