727 research outputs found
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Zipping up Tetraazaperylene: Synthesis of Tetraazacoronenes via Double Coupling in the Bay Positions [data]
No full textSubstituted tetraazacoronene fluorophores have been obtained selectively by double Suzuki–Miyaura cross coupling of symmetrically substituted 1,2-bis(pinacolatoboryl)alkenes with a bay-substituted octaazaperopyrenedioxide (OAPPDO). Subsequent Scholl reaction of the dimethoxyphenylated derivative allowed further π-extension of the azaperylene core, yielding a highly redox-active bis(phenanthro)tetraazacoronene
CO-NNECT
No full textThis repository contains our path generation framework Co-NNECT, in which we combine two models for establishing knowledge relations and paths between concepts from sentences, as a form of explicitation of implicit knowledge: COREC-LM (COmmonsense knowledge RElation Classification using Language Models), a relation classification system that we developed for classifying commonsense knowledge relations (CO-NNECT/COREC-LM); and COMET, a target prediction system developed by Bosselut et al., 2019, which we adapt for Forwardchaining (CO-NNECT/Forwardchaining)
Multi-material single-vat dual-wavelength DLP 4D printing of shape memory polymers [data]
No full textShape memory polymers (SMP) are a fascinating class of responsive materials with potential in various fields, especially when combined with precise structuring by 3D printing strategies such as digital light processing (DLP). However, such 3D printing techniques are usually limited to homogeneous single material 4D structures restricting potential applicability. In this study we present a dual-wavelength multi-material DLP-based strategy for the fabrication of 4D multi-material structures with a spatial controllable shape memory effect from a single ink formulation. To achieve this, we designed an ink system, allowing generation of static as well as responsive parts depending on the applied curing wavelength with a high spatial control. Specifically, the multi-material ink formulations are composed of epoxide-based, (meth)acrylate-based monomers and a radical photoinitiator – providing appropriate selectivity of the polymerization mechanism. A germanium-based derivative has been selected as a suitable radical photoinitiator active in the blue wavelength regime (460 nm), enabling the exclusive formation of poly(meth)acrylate-based networks exhibiting shape memory properties. When printing with UV light (365 nm), simultaneous formation of epoxy and polymethacrylate networks results in a non-responsive material. Finally, by exploiting these capabilities, the fabrication of multi-material 4D structures with spatially controllable shape memory properties are successfully demonstrated
An Automatic Iterative Random Forest approach to derive gully activity maps in large areas with training data scarcity [Data and Source Code]
No full textGullies are landforms with specific patterns of shape, topography, hydrology, vegetation, and soil characteristics. Remote sensing products (TanDEM-X, Sentinel-1, and Sentinel-2) serve as inputs into an iterative algorithm, initialized using a micro-mapping simulation as training data, to map gullies in the northwestern of Namibia. A Random Forest Classifier examines pixels with similar characteristics in a pool of unlabeled data, and gully objects are detected where high densities of gully pixels are enclosed by an alpha shape. Gully objects are used in subsequent iterations following a mechanism where the algorithm uses the most reliable pixels as gully training samples. The gully class continuously grows until an optimal scenario in terms of accuracy is achieved. Results are benchmarked with manually tagged gullies (initial gully labeled area 98%, with 60% in the gully class, Cohen Kappa >0.5, Matthews Correlation Coefficient >0.5, and receiver operating characteristic Area Under the Curve >0.89. Hence, our method outlines gullies keeping low false-positive rates while the classification quality has a good balance for the two classes (gully/no gully). Results show the most significant gully descriptors as the high temporal radar signal coherence (22.4%) and the low temporal variability in Normalized Difference Vegetation Index (21.8%). This research builds on previous studies to face the challenge of identifying and outlining gully-affected areas with a shortage of training data using global datasets, which are then transferable to other large (semi-) arid regions
Ergänzungsdaten zu: The osseous industry of the LGM site Kammern-Grubgraben (Lower Austria), excavations 1985–1994, and its position within the European Late Upper Palaeolithic
No full textThe well-known Upper Palaeolithic open-air site of Kammern-Grubgraben (Lower Austria) is so far the only Central European Last Glacial Maximum (LGM) site with preserved bone industry. This contribution presents the antler, ivory, and bone artefacts recovered during the 1985–1994 excavations. Among several thousand marrow-fractured osseous fragments, only 65 pieces, most of which are attributable to the 23.5–22 ka calBP main occupation, were identified as artefacts related to tool production. Shed antler, predominantly from reindeer, mammoth ivory, and longbones of large mammals served as raw materials. Transversal sectioning and production of pre-forms were carried out exclusively by direct percussion, and pre-forms were modified into tools by invasive longitudinal scraping. Eyed needles, predominantly produced on bone, are the most frequent tool type, followed by projectile points. Noticeable are two perforated batons. The osseous industry of Grubgraben mirrors its intermediate geographic location in the cultural landscape of the LGM: whereas massive-based projectile points and perforated rods connect it to the Eastern European early Epigravettian sphere, a projectile point with a single-bevelled base finds parallels in the Western European Badegoulian. Debitage by fracturing and eyed needles appear to be common traits of many LGM traditions and hence attest to a quick dissemination of certain typo-technological features throughout Europe. Similar observations can be made regarding the lithic industry. Of note is a decorated perforated baton from the uppermost archaeological horizon AL1. Although we consider the single, conspicuously young radiocarbon date of 20.5 ka calBP from AL1 as unreliable, the perforated baton and peculiarities in both the lithic industry and the faunal record nevertheless suggest another later, early post-LGM occupation at Grubgraben. This might relate to the 19–18 ka calBP, early Middle Magdalenian that is attested 300 km to the north at Maszycka cave in Poland. Like other Central European sites north of 47°, Grubgraben does not provide any conclusive evidence for human presence during the second half of the LGM (22–19 ka calBP), and thus the precise conduct of the post-LGM recolonisation of Central Europe remains an open question
Codices Palatini latini – Juristische Handschriften
No full textHere you can find the descriptions of the Latin Palatine manuscripts as published in the manuscripts catalog "Die juristischen Handschriften der Codices Palatini Latini in der Vatikanischen Bibliothek (Cod. Pal. lat. 621-813)", edited by Thorsten Huthwelker, Wolfgang Metzger und Christoph Winterer, Heidelberg 2024 (Kataloge der Universitätsbibliothek Heidelberg 13). The description for each manuscript was subsequently recorded as TEI-XML file by XML encoding in accordance with TEI-P5 using GND standard vocabulary.
These TEI files follow an outdated TEI schema originally developed at the Herzog August Bibliothek Wolfenbüttel and contain some ad hoc solutions which were chosen pragmatically in Heidelberg and which do not always comply with the TEI Guidelines. A future migration of the dataset into a fully TEI-compliant format is considered as desirable
Pentacene to Octacene: The Limit of Fourfold TIPS-Ethynylation [data]
No full textSoluble acenes beyond hexacene are rare. Their sensitivity complicates isolation, purification and application in devices. To increase the stability of acenes, functionalization with trialkylsilylethynyl substituents prevents [4+4] dimerization and oxidation. At the same time such acenes are soluble and processible. Here we present the modular synthesis of fourfold TIPS-ethynylated pentacenes to octacenes and investigate their optical and redox properties, frontier orbital positions (CV, DFT calculations) as well as their stability in solution (UV/vis, NMR spectroscopy). We also investigated their magnetic properties as a function of acene length. Pentacene, hexacene and heptacene are sufficiently stable to serve as semiconductors in thin-film transistors - the octacene rapidly decays to its butterfly dimer evidence by time-dependent NMR spectroscopy and crystal structure analysis
Ergänzungsdaten zu: Marco Cornaglia: GIS analysis and the abandoned settlements in Pausanias’ Periegesis: a methodological proposal
No full textThe paper aims to provide a methodological proposal for applying GIS softwares to the literary analysis of classical texts. The descriptions from Pausanias' Periegesis have been georeferenced in a digital maps after being adapted to a specific taxonomy, aimed to facilitate the search for the mapped data. From the complete digitization of the work, a series of case studies were derived in order to illustrate possible applications, particularly in light of the specific phenomenon of the distribution of abandoned settlements in Roman-era Greece, part of the author's narration.
Human resource needs and costs for nurse-led HIV pre-exposure prophylaxis provision in primary care in Eswatini and opportunities for task sharing [Research Data]
No full textBackground: The global expansion of HIV pre-exposure prophylaxis (PrEP) includes health systems that face a shortage of skilled health care workers (HCWs). We estimated the human resource needs and costs for providing PrEP in nurse-led primary care clinics in Eswatini. Furthermore, we assessed potential cost savings from task sharing between nurses and other HCW cadres.
Methods: We conducted a time-and-motion and costing study in a PrEP demonstration project between August 2017 and January 2019. A form for recording time and performed activities (“motion”) was filled by HCWs of six primary care clinics. To estimate the human resource needs for specific PrEP activities, we allocated recorded times to performed PrEP activities using linear regression with and without adjusting for a workflow interruption, that is, if a client was seen by different HCWs or by the same HCW at different times. We assessed a base case in which a nurse provides all PrEP activities and five task shifting scenarios, of which four include workflow interruptions due to task sharing between different HCW cadres.
Results: On average, PrEP initiation required 29 min (95% CI 25–32) of HCW time and PrEP follow-up 16 min (95% CI 14–18). The HCW time cost 2.54 (UI 1.07–4.64) for PrEP follow-up when all activities were performed by a nurse. Time costs were 1.06–2.60 (UI 0.30–5.44) for PrEP follow-up when nurses shared tasks with HCWs from lower cadres. Interruptions of the workflow added, on average, 3.4 min (95% CI 0.69–6.0) to the time HCWs needed for a given number of PrEP activities. The cost of an interrupted workflow was estimated at $0.048–0.87 (UI 0.0098–1.63) depending on whose time need increased.
Conclusions: A global shortage of skilled HCWs could slow the expansion of PrEP. Task shifting to lower-cadre HCW in nurse-led PrEP provision can free up nurse time and reduce the cost of PrEP provision even if interruptions associated with task sharing increase the overall human resource need
Two-Photon Laser Printing of 3D Multicolor Emissive Polymer Microstructures [data]
No full textIn this study, we aim for the fabrication of precise multi-color 3D microstructures utilizing organic emitters. We have carefully selected dyes with red, green, and blue (RGB) emission characteristics and incorporated them into printable formulations suitable for two-photon laser printing (2PLP). Specifically, we have chosen an OAPPDO derivative, a boron dipyrromethene difluoride (BODIPY), and a coumarin derivative as red, green, and blue emitters, respectively, each functionalized with acrylate groups. The photopolymerizable groups allow for covalent linking to the polymer network formed in the subsequent step, enabling precise control over the incorporation of the desired emitter. The formulations including these three photopolymerizable dyes have been employed to print emissive 3D microstructures via 2PLP. Furthermore, we have studied and optimized their printability, resolution, and emission properties for each case. In a last step, we have fabricated complex multi-material 3D microstructures, demonstrating the versatility and potential application of our method in displays or anti-counterfeiting systems