University of Paderborn

About: University of Paderborn is a education organization based out in Paderborn, Nordrhein-Westfalen, Germany. It is known for research contribution in the topics: Computer science & Context (language use). The organization has 6684 authors who have published 16929 publications receiving 323154 citations.

Synthesis and cytotoxic activity of C-glycosidic nicotinamide riboside analogues.

Abstract: The C-glycosidic nicotinamide riboside analogue (2) was prepared by reaction of ribonolactone 24 with the lithiated oxazoline 19 followed by triethylsilane reduction to 26 and deprotection. Selective phosphorylation to the pseudonucleotide 34 was effected via the isopropylidene compound 33. In contrast to the benzoic acid riboside (28) the benzamide riboside (2) showed extremely high cytotoxicity at nanomolar concentrations to S49.1 lymphoma cells but only slightly increased dexamethasone toxicity.

Causal Linkages Between Domestic Terrorism and Economic Growth

Abstract: We use the Hsiao–Granger method to test for terrorism–growth causality for seven Western European countries. In bivariate settings, the impact of economic performance on domestic terrorism is very strong. In trivariate settings, the impact of performance on terrorism diminishes. In general, we find that economic performance leads terrorist violence in robust ways only for three out of seven countries. Terrorism is almost never found to causally influence growth in bivariate and trivariate specifications. Our findings indicate that the role of economic performance in determining terrorist violence appears to have been important for some countries, whereas all attacked economies have been successful in adjusting to the threat of terrorism.

Coherent optical communication: towards realtime systems at 40 Gbit/s and beyond.

Abstract: Coherent optical communication systems promise superior performance, but their realization in real time also poses big technical challenges. After an introduction the potential of coherent optical transmission systems is shown as manifested in offline experiments. Then we present key components that are necessary to realize these systems in real time. We review recent achievements in realtime coherent communication and finally present the results of a realtime QPSK transmission system with a 3×3 coupler in the receiver. The achieved BER at a data rate of 1.4 Gbit/s is well below the FEC threshold.

Fatigue crack growth behavior and mechanical properties of additively processed EN AW-7075 aluminium alloy

Abstract: Selective Laser Melting (SLM ® ), an additive manufacturing (AM) technology, allows manufacturing of geometrically complex metallic parts directly. In the SLM technology, a high energy laser beam is applied to melt a thin layer of the metallic powder according to the information provided by CAD files. This layer-wise manufacturing offers the opportunity to create complex parts for application areas e.g., aerospace and automotive industries where the lightweight design has been and still is a priority for material development in recent years. Therefore, the materials such as aluminium alloys come into focus due to their low density and high mechanical characteristics. In view of these aspects, previously unused high strength aluminium alloy EN AW-7075 powder was produced by gas atomization and processed by SLM ® as presented in this paper. Initially, specimens were produced to examine monotonic and fracture mechanical properties in different building directions. The tensile tests and the fracture examinations show an anisotropic material behaviour. The fatigue crack growth curves have the double S shape, which is typical of aluminium. Mechanical characteristics obtained from the experiments are lower in comparison to the conventionally manufactured aluminium alloy properties.

Multiple-Access Relay Channel with Network Coding and Non-Ideal Source-Relay Channels

Abstract: The multiple-access relay channel (MARC) based on network coding has been proposed in recent papers as a means to achieve diversity gain in wireless networks, at the same time reducing the number of transmissions by a relay node. In MARC, multiple sources transmit to a common destination with the assistance of a single relay. In a network-coding-based realization of MARC, the relay merges the messages received from the two sources and forwards them to the destination; at the destination, the sources' messages can be recovered from either their direct transmissions or by performing additional network coding. In this work, performance analysis in the form of outage probability and coverage area, when non-ideal source-relay links exist, is performed. The relay is assumed to operate either in static or adaptive mode, and comparisons with the conventional MARC and point-to-point transmission are made. The outage results show that the conventional MARC system perform better when the source-relay links are high quality. Network-coding- based MARC operated in adaptive mode has better performance when the quality of the source-relay links are poor, and this system has better coverage area.