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- ItemRing-Closure Mechanisms Mediated by Laccase to Synthesize Phenothiazines, Phenoxazines, and Phenazines(Washington, DC : ACS Publications, 2020) Hahn, Veronika; Mikolasch, Annett; Weitemeyer, Josephine; Petters, Sebastian; Davids, Timo; Lalk, Michael; Lackmann, Jan-Wilm; Schauer, FriederThe green and environmentally friendly synthesis of highly valuable organic substances is one possibility for the utilization of laccases (EC 1.10.3.2). As reactants for the herein described syntheses, different o-substituted arylamines or arylthiols and 2,5-dihydroxybenzoic acid and its derivatives were used. In this way, the formation of phenothiazines, phenoxazines, and phenazines was achieved in aqueous solution mediated by the laccase of Pycnoporus cinnabarinus in the presence of oxygen. Two types of phenothiazines (3-hydroxy- and 3-oxo-phenothiazines) formed in one reaction assay were described for the first time. The cyclization reactions yielded C–N, C–S, or C–O bonds. The syntheses were investigated with regard to the substitution pattern of the reaction partners. Differences in C–S and C–N bond formations without cyclization are discussed.
- ItemEVENTSKG: A 5-Star Dataset of Top-Ranked Events in Eight Computer Science Communities(Berlin ; Heidelberg : Springer, 2019) Fathalla, Said; Lange, Christoph; Auer, Sören; Hitzler, Pascal; Fernández, Miriam; Janowicz, Krzysztof; Zaveri, Amrapali; Gray, Alasdair J.G.; Lopez, Vanessa; Haller, Armin; Hammar, KarlMetadata of scientific events has become increasingly available on the Web, albeit often as raw data in various formats, disregarding its semantics and interlinking relations. This leads to restricting the usability of this data for, e.g., subsequent analyses and reasoning. Therefore, there is a pressing need to represent this data in a semantic representation, i.e., Linked Data. We present the new release of the EVENTSKG dataset, comprising comprehensive semantic descriptions of scientific events of eight computer science communities. Currently, EVENTSKG is a 5-star dataset containing metadata of 73 top-ranked event series (almost 2,000 events) established over the last five decades. The new release is a Linked Open Dataset adhering to an updated version of the Scientific Events Ontology, a reference ontology for event metadata representation, leading to richer and cleaner data. To facilitate the maintenance of EVENTSKG and to ensure its sustainability, EVENTSKG is coupled with a Java API that enables users to add/update events metadata without going into the details of the representation of the dataset. We shed light on events characteristics by analyzing EVENTSKG data, which provides a flexible means for customization in order to better understand the characteristics of renowned CS events.
- ItemSperm Micromotors for Cargo Delivery through Flowing Blood(Washington, DC : American Chemical Society, 2020) Xu, Haifeng; Medina-Sánchez, Mariana; Maitz, Manfred F.; Werner, Carsten; Schmidt, Oliver G.Micromotors are recognized as promising candidates for untethered micromanipulation and targeted cargo delivery in complex biological environments. However, their feasibility in the circulatory system has been limited due to the low thrust force exhibited by many of the reported synthetic micromotors, which is not sufficient to overcome the high flow and complex composition of blood. Here we present a hybrid sperm micromotor that can actively swim against flowing blood (continuous and pulsatile) and perform the function of heparin cargo delivery. In this biohybrid system, the sperm flagellum provides a high propulsion force while the synthetic microstructure serves for magnetic guidance and cargo transport. Moreover, single sperm micromotors can assemble into a train-like carrier after magnetization, allowing the transport of multiple sperm or medical cargoes to the area of interest, serving as potential anticoagulant agents to treat blood clots or other diseases in the circulatory system.
- ItemRapid Colorimetric Detection of Pseudomonas aeruginosa in Clinical Isolates Using a Magnetic Nanoparticle Biosensor(Washington, DC : ACS Publications, 2019) Alhogail, Sahar; Suaifan, Ghadeer A.R.Y; Bikker, Floris J.; Kaman, Wendy E.; Weber, Karina; Cialla-May, Dana; Popp, Jürgen; Zourob, Mohammed M.A rapid, sensitive, and specific colorimetric biosensor based on the use of magnetic nanoparticles (MNPs) was designed for the detection of Pseudomonas aeruginosa in clinical samples. The biosensing platform was based on the measurement of P. aeruginosa proteolytic activity using a specific protease substrate. At the N-terminus, this substrate was covalently bound to MNPs and was linked to a gold sensor surface via cystine at the C-terminus of the substrates. The golden sensor appears black to naked eyes because of the coverage of the MNPs. However, upon proteolysis, the cleaved peptide–MNP moieties will be attracted by an external magnet, revealing the golden color of the sensor surface, which can be observed by the naked eye. In vitro, the biosensor was able to detect specifically and quantitatively the presence of P. aeruginosa with a detection limit of 102 cfu/mL in less than 1 min. The colorimetric biosensor was used to test its ability to detect in situ P. aeruginosa in clinical isolates from patients. This biochip is anticipated to be useful as a rapid point-of-care device for the diagnosis of P. aeruginosa-related infections.
- ItemFe3O4 Nanoparticles Grown on Cellulose/GO Hydrogels as Advanced Catalytic Materials for the Heterogeneous Fenton-like Reaction(Washington, DC : ACS Publications, 2019) Chen, Yian; Pötschke, Petra; Pionteck, Jürgen; Voit, Brigitte; Qi, HaisongCellulose/graphene oxide (GO)/iron oxide (Fe3O4) composites were prepared by coprecipitating iron salts onto cellulose/GO hydrogels in a basic solution. X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared, and X-ray diffraction characterization showed that Fe3O4 was successfully coated on GO sheets and cellulose. Cellulose/GO/Fe3O4 composites showed excellent catalytic activity by maintaining almost 98% of the removal of acid orange 7 (AO7) and showed stability over 20 consecutive cycles. This performance is attributable to the synergistic effect of Fe3O4 and GO during the heterogeneous Fenton-like reaction. Especially, the cellulose/GO/Fe3O4 composites preserve their activity by keeping the ratio of Fe3+/Fe2+ at 2 even after 20 catalysis cycles, which is supported by XPS analysis.
- ItemDevulcanization of Waste Rubber and Generation of Active Sites for Silica Reinforcement(Washington, DC : ACS Publications, 2019) Ghorai, Soumyajit; Mondal, Dipankar; Hait, Sakrit; Ghosh, Anik Kumar; Wiessner, Sven; Das, Amit; De, DebapriyaEach year, hundreds of millions of tires are produced and ultimately disposed into nature. To address this serious environmental issue, devulcanization could be one of the sustainable solutions that still remains as one of the biggest challenges across the globe. In this work, sulfur-vulcanized natural rubber (NR) is mechanochemically devulcanized utilizing a silane-based tetrasulfide as a devulcanizing agent, and subsequently, silica (SiO2)-based rubber composites are prepared. This method not only breaks the sulfur–sulfur cross-links but also produces reactive poly(isoprene) chains to interact with silica. The silica natural rubber composites are prepared by replacing 30% fresh NR by devulcanized NR with varying contents of silica. The composites exhibit excellent mechanical properties, tear strength, abrasion resistance, and dynamic mechanical properties as compared with the fresh natural rubber silica composites. The tensile strength of devulcanized rubber-based silica composites is ∼20 MPa, and the maximum elongation strain is ∼921%. The devulcanized composites are studied in detail by chemical, mechanical, and morphological analyses. Thus, the value added by the devulcanized rubber could attract the attention of recycling community for its sustainable applications.
- ItemThe Research Core Dataset (KDSF) in the Linked Data context(Amsterdam [u.a.] : Elsevier, 2019) Walther, Tatiana; Hauschke, Christian; Kasprzik, Anna; Sicilia, Miguel-Angel; Simons, Ed; Clements, Anna; de Castro, Pablo; Bergström, JohanThis paper describes our efforts to implement the Research Core Dataset (“Kerndatensatz Forschung”; KDSF) as an ontology in VIVO. KDSF is used in VIVO to record the required metadata on incoming data and to produce reports as an output. While both processes need an elaborate adaptation of the KDSF specification, this paper focusses on the adaptation of the KDSF basic data model for recording data in VIVO. In this context, the VIVO and KDSF ontologies were compared with respect to domain, syntax, structure, and granularity in order to identify correspondences and mismatches. To produce an alignment, different matching approaches have been applied. Furthermore, we made necessary modifications and extensions on KDSF classes and properties.
- ItemAn OER Recommender System Supporting Accessibility Requirements(New York : Association for Computing Machinery, 2020) Elias, Mirette; Tavakoli, Mohammadreza; Lohmann, Steffen; Kismihok, Gabor; Auer, Sören; Gurreiro, Tiago; Nicolau, Hugo; Moffatt, KarynOpen Educational Resources are becoming a significant source of learning that are widely used for various educational purposes and levels. Learners have diverse backgrounds and needs, especially when it comes to learners with accessibility requirements. Persons with disabilities have significantly lower employment rates partly due to the lack of access to education and vocational rehabilitation and training. It is not surprising therefore, that providing high quality OERs that facilitate the self-development towards specific jobs and skills on the labor market in the light of special preferences of learners with disabilities is difficult. In this paper, we introduce a personalized OER recommeder system that considers skills, occupations, and accessibility properties of learners to retrieve the most adequate and high-quality OERs. This is done by: 1) describing the profile of learners with disabilities, 2) collecting and analysing more than 1,500 OERs, 3) filtering OERs based on their accessibility features and predicted quality, and 4) providing personalised OER recommendations for learners according to their accessibility needs. As a result, the OERs retrieved by our method proved to satisfy more accessibility checks than other OERs. Moreover, we evaluated our results with five experts in educating people with visual and cognitive impairments. The evaluation showed that our recommendations are potentially helpful for learners with accessibility needs.
- ItemLas Pailas geothermal field - Central America case study: Deciphering a volcanic geothermal play type through the combination of optimized geophysical exploration methods and classic geological conceptual models of volcano-tectonic systems(London [u.a.] : Institute of Physics, 2019) Salguero, Leonardo Solís; Rioseco, Ernesto MenesesSustainable exploitation strategies of high-enthalpy geothermal reservoirs in a volcanic geothermal play type require an accurate understanding of key geological structures such as faults, cap rock and caldera boundaries. Of same importance is the recognition of possible magmatic body intrusions and their morphology, whether they are tabular like dikes, layered like sills or domes. The relative value of those magmatic bodies, their age, shape and location rely on the role they play as possible local heat sources, hydraulic barriers between reservoir compartments, and their far-reaching effect on the geochemistry and dynamics of fluids. Obtaining detailed knowledge and a more complete understanding at the early stages of exploration through integrated geological, geophysical and geochemical methods is essential to determine promising geothermal drilling targets for optimized production/re-injection schemes and for the development of adequate exploitation programs. Valuable, extensive geophysical data gathered at Las Pailas high-enthalpy geothermal field at northwestern Costa Rica combined with detailed understanding of the geological structures in the underground may represent a sound basis for an in-depth geoscientific discussion on this topic. Currently, the German cooperation for the identification of geothermal resources in Central America, implemented by the Federal Institute for Geosciences and Natural Resources (BGR), supports an international and interdisciplinary effort, driven by the Instituto Costarricense de Electricidad (ICE) with different international and national research institutions, including the Leibniz Institute for Applied Geophysics (LIAG). The discussions and joint studies refer to the optimized utilization of geophysical and geological methods for geothermal exploration in the Central American region, using the example of Las Pailas Geothermal Field. The results should contribute to a better understanding of the most appropriate geothermal exploration concepts for complex volcanic field settings in Central America.
- ItemCheck square at CheckThat! 2020: Claim Detection in Social Media via Fusion of Transformer and Syntactic Features(Aachen, Germany : RWTH Aachen, 2020) Cheema, Gullasl S.; Hakimov, Sherzod; Ewerth, Ralph; Cappellato, Linda; Eickhoff, Carsten; Ferro, Nicola; Névéol, AurélieIn this digital age of news consumption, a news reader has the ability to react, express and share opinions with others in a highly interactive and fast manner. As a consequence, fake news has made its way into our daily life because of very limited capacity to verify news on the Internet by large companies as well as individuals. In this paper, we focus on solving two problems which are part of the fact-checking ecosystem that can help to automate fact-checking of claims in an ever increasing stream of content on social media. For the first prob-lem, claim check-worthiness prediction, we explore the fusion of syntac-tic features and deep transformer Bidirectional Encoder Representations from Transformers (BERT) embeddings, to classify check-worthiness of a tweet, i.e. whether it includes a claim or not. We conduct a detailed feature analysis and present our best performing models for English and Arabic tweets. For the second problem, claim retrieval, we explore the pre-trained embeddings from a Siamese network transformer model (sentence-transformers) specifically trained for semantic textual similar-ity, and perform KD-search to retrieve verified claims with respect to a query tweet.