Magnetic resonance imaging as a tool for quality control in extrusion-based bioprinting

Bioprinting is gaining importance for the manufacturing of tailor-made hydrogel scaffolds in tissue engineering, pharmaceutical research and cell therapy. However, structure fidelity and geometric deviations of printed objects heavily influence mass transport and process reproducibility. Fast, three-dimensional and nondestructive quality control methods will be decisive for the approval in larger studies or industry. Magnetic resonance imaging (MRI) meets these requirements for characterizing heterogeneous soft materials with different properties. Complementary to the idea of decentralized 3D printing, magnetic resonance tomography is common in medicine, and image data processing tools can be transferred system-independently. In this study, a MRI measurement and image analysis protocol was evaluated to jointly assess the reproducibility of three different hydrogels and a reference material. Critical parameters for object quality, namely porosity, hole areas and deviations along the height of the scaffolds are discussed. Geometric deviations could be correlated to specific process parameters, anomalies of the ink or changes of ambient conditions. This strategy allows the systematic investigation of complex 3D objects as well as an implementation as a process control tool. Combined with the monitoring of metadata this approach might pave the way for future industrial applications of 3D printing in the field of biopharmaceutics

Monoskop Exhibition Library

The Exhibition Library reimagines the medium of art exhibition as well as that of art catalogue. Catalogues carry exhibitions through time and space, figuring as tropes for imagining arrangements and the course of works and settings they describe. However, they rarely give us a clue about what really happened, since they are often made before the show opens. Rather than documenting it, they often stand on their own, almost as if another work on display, truly as an artistic medium on its own. For this work, artists, designers, curators, poets and collectives created thirty catalogues of imaginary exhibitions. Exploring both the potential and impossible in art, the resulting exhibition library also serves as a “library of exhibitions.

pSense - Maintaining a Dynamic Localized Peer-to-Peer Structure for Position Based Multicast in Games

This paper presents an algorithm for creating and maintaining a dynamic localized peer-to-peer overlay network with its main application to massively multiplayer games. In these games, players reside in a large game world with many thousands of players but each player has typically a limited vision range. In our solution, players join the network as peers and mainly connect to neighbor peers that are close to them in the virtual game world. As players move in the game they change their neighbors dynamically with very little overhead. Peers can multicast messages that are received by peers in their locality very fast (often faster than in client-server solutions) while players that are further away receive them later or not at all. Not receiving messages from remote players is important in order to not cause the load on each peer to grow with the number of players in the game. Our performance analysis confirms that our solution allows for dynamic game worlds of practically unlimited size, only limited in scale by the number of players within the vision range. 1

Microplastic in the water cycle : sampling, sample preparation, analyses, occurrence and assessment

Gedruckt erschienen im Universitätsverlag der TU Berlin, ISBN 978-3-7983-3162-4Das interdisziplinäre Forschungsprojekt MiWa widmete sich grundlegenden Fragestellungen zur Analytik und Wirkung von Mikroplastik-Partikeln im Wasserkreislauf. Es wurden Methoden der Umweltprobennahme, der Probenaufbereitung und verschiedene Detektionsverfahren zur Charakterisierung und Quantifizierung von Mikroplastik intensiv untersucht, miteinander verglichen und weiterentwickelt. Öko- und humantoxikologische Untersuchungen dienten dem Zweck, die potenziell von Mikroplastik ausgehende Gefährdung für die aquatische Umwelt und den Menschen zu analysieren und zu bewerten. Eine Harmonisierung und Standardisierung von Methoden der Probennahme, Probenaufbereitung und Mikroplastik-Detektion sind trotz der erheblichen Fortschritte derzeit nur teilweise möglich. Die ökotoxikologischen Studien zeigen zwar die Aufnahme von Mikroplastik-Partikeln durch einige Organismen, jedoch konnte bisher keine schädigende Wirkung nachgewiesen werden. Dabei wurden für eine Auswahl aquatischer Modellspezies sowohl Szenarien direkter als auch indirekter Exposition innerhalb einer Nahrungskette betrachtet. Interaktionen mit menschlichen Modellzellen wurden bislang nur bei Mikroplastik-Partikeln mit Größen weit unterhalb von 1 µm (also Nanoplastik) beobachtet. Eine umfassende Bewertung ist bislang nicht möglich.The interdisciplinary research project MiWa focused on principle knowledge gaps of analytical detection and effects of microplastic in fresh water cycles. Methods for environmental sampling, sample preparation and different analytical identification and quantification were intensively investigated, compared and further developed. Toxicological studies were conducted to assess potential risks of microplastic particles towards the environment and human health. Harmonization and standardization are still only partially possible despite various improvements. The eco-toxicological experiments confirmed the intake of microplastic particles by different organisms but no hazardous effects could be found. Both direct ingestions and indirect exposition within food webs were tested. Interactions with exemplary human cells were only observed for particle sizes far below 1 µm (thus nanoplastic). An assessment is currently only possible to a limited extent.BMBF, 02WRS1378, Mikroplastik im Wasserkreislauf (MiWa