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    Optimized expression and purification of a soluble BMP2 variant based on in-silico design

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    Bone morphogenetic protein 2 (BMP21) is a highly interesting therapeutic growth factor due to its strong osteogenic/osteoinductive potential. However, its pronounced aggregation tendency renders recombinant and soluble production troublesome and complex. While prokaryotic expression systems can provide BMP2 in large amounts, the typically insoluble protein requires complex denaturation-renaturation procedures with medically hazardous reagents to obtain natively folded homodimeric BMP2. Based on a detailed aggregation analysis of wildtype BMP2, we designed a hydrophilic variant of BMP2 additionally containing an improved heparin binding site (BMP2-2Hep-7M). Consecutive optimization of BMP2-2Hep-7M expression and purification enabled production of soluble dimeric BMP2-2Hep-7M in high yield in E. coli. This was achieved by a) increasing protein hydrophilicity via introducing seven point mutations within aggregation hot spots of wildtype BMP2 and a longer N-terminus resulting in higher affinity for heparin, b) by employing E. coli strain SHuffle® T7, which enables the structurally essential disulfide-bond formation in BMP2 in the cytoplasm, c) by using BMP2 variant characteristic soluble expression conditions and application of L-arginine as solubility enhancer. The BMP2 variant BMP2-2Hep-7M shows strongly attenuated although not completely eliminated aggregation tendency

    Experimental Examination of Radiation Doses Of Dual-and Single-Energy Computed Tomography in Chest And Upper Abdomen in a Phantom Study

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    The aim of this phantom study is to examine radiation doses of dual- and single-energy computed tomography (DECT and SECT) in the chest and upper abdomen for three different multi-slice CT scanners. A total of 34 CT protocols were examined with the phantom N1 LUNGMAN. Four different CT examination types of different anatomic regions were performed both in single- and dual-energy technique: chest, aorta, pulmonary arteries for suspected pulmonary embolism and liver. Radiation doses were examined for the CT dose index CTDIvol and dose-length product (DLP). Radiation doses of DECT were significantly higher than doses for SECT. In terms of CTDIvol, radiation doses were 1.1–3.2 times higher, and in terms of DLP, these were 1.1–3.8 times higher for DECT compared with SECT. The third-generation dual-source CT applied the lowest dose in 7 of 15 different examination types of different anatomic regions

    Enhancing optical-flow-based control by learning visual appearance cues for flying robots

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    Flying insects employ elegant optical-flow-based strategies to solve complex tasks such as landing or obstacle avoidance. Roboticists have mimicked these strategies on flying robots with only limited success, because optical flow (1) cannot disentangle distance from velocity and (2) is less informative in the highly important flight direction. Here, we propose a solution to these fundamental shortcomings by having robots learn to estimate distances to objects by their visual appearance. The learning process obtains supervised targets from a stability-based distance estimation approach. We have successfully implemented the process on a small flying robot. For the task of landing, it results in faster, smooth landings. For the task of obstacle avoidance, it results in higher success rates at higher flight speeds. Our results yield improved robotic visual navigation capabilities and lead to a novel hypothesis on insect intelligence: behaviours that were described as optical-flow-based and hardwired actually benefit from learning processes

    A Crypto-Token Based Charging Incentivization Scheme for Sustainable Light Electric Vehicle Sharing

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    The ecological impact of shared light electric vehicles (LEV) such as kick scooters is still widely discussed. Especially the fact that the vehicles and batteries are collected using diesel vans in order to charge empty batteries with electricity of unclear origin is perceived as unsustainable. A better option could be to let the users charge the vehicles themselves whenever it is necessary. For this, a decentralized,flexible and easy to install network of off-grid solar charging stations could bring renewable electricity where it is needed without sacrificing the convenience of a free float sharing system. Since the charging stations are powered by solar energy the most efficient way to utilize them would be to charge the vehicles when the sun is shining. In order to make users charge the vehicle it is necessary to provide some form of benefit for them doing so. This could be either a discount or free rides. A particularly robust and well-established mechanism is controlling incentives via means of blockchain-based cryptotokens. This paper demonstrates a crypto-token based scheme for incentivizing users to charge sharing vehicles during times of considerable solar irradiation in order to contribute to more sustainable mobility services

    Investigation of the saving potential of noble catalyst material in polymer electrolyte membrane fuel cells

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    The energy transition towards renewable energies for the overall energy supply (electricity, heat, mobility, etc.) is already well advanced and the further expansion is planned. The volatility of renewable energies is being addressed by the hydrogen technology. However, there is still a need for optimization of the cost-efficient reconversion of stored energy in the form of hydrogen, e.g. in applications for decarbonization of the power grid or of the mobility sector. For instance, the cost of an automotive low-temperature polymer electrolyte membrane fuel cell (PEMFC) must be lowered by reducing the platinum loading and the lifetime must be further improved to achieve the competitiveness of this technology. The aim of the present thesis was to develop membrane electrode assemblies (MEAs) with ultra-low platinum loading, high performance and increased lifetime for the use in PEMFCs. They are fabricated by an innovative MEA preparation process based on the pulse electrodeposition of platinum (Pt) using carbon nanofibers (CNFs) as a catalyst support with enhanced resistance to carbon oxidation reaction. The design of the MEA preparation process and the development of ultra-low Pt-loaded anodes and cathodes was the starting point of this thesis. It was found that the Pt/CNF catalyst used on the anode side had better characteristics than a commercial Pt/C catalyst, since the same power output of 0.525 W cm-2 was obtained with 10 ....

    Verfassungsmäßigkeit der Regulierung des Immobilienmarktes durch den Landesgesetzgeber

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    Der Aufsatz untersucht die materielle und formelle Verfassungsmäßigkeit des Mietendeckels nach Landesrecht am Beispiel Berlin

    Grundlagen der Informatik und Programmierung 1 (WS 2020/21) -- "4.5 Datentypen und ihre Darstellung: Zeichen und Zeichenketten"

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    Vorlesung im Wintersemester 2020/21, B.Sc. Informatik.Softwaresysteme, B.Sc. Elektrotechnik - Automation Themen: - einzelne Zeichen - Zeichenketten/Strings = Zeichen-Arrays - Terminator - Ein- und Ausgab

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