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Strategien zur metabolischen Markierung von RNA lebender Zellen mittels IEDDA-Reaktion
Get PDFSeit der Einführung der bioorthogonalen Reaktionen durch Bertozzi et al. in den frühen 2000er Jahren, hat sich die bioorthogonale Markierung zu einem leistungsfähigen und vielseitigen Werkzeug für die selektive Markierung von Biomolekülen in ihrer nativen zellulären Umgebung entwickelt. Für die Untersuchung der RNA Synthese und -Dynamik in Zellen sind effiziente Markierungsstrategien erforderlich, die nicht nur mit der zellulären Umgebung kompatibel sind, sondern auch in lebenden Zellen angewendet werden können. Im Rahmen dieser Arbeit wurden daher Strategien entwickelt, die den metabolischen Einbau von Nukleosid- bzw. Nukleotid-Analoga mit hoch reaktiven chemischen Reportergruppen in neu synthetisierte zelluläre RNA ermöglichen. Eine Detektion der markierten RNA mit einem fluorogenen Tetrazin Fluorophor Konjugat mittels IEDDA Reaktion ermöglicht eine waschfreie, kontrastreiche Echtzeit Visualisierung von RNA in lebenden Zellen. Neben dem Einsatz eines 1 MCP modifizierten Nukleosids wurden insbesondere modifizierte Nukleosidtriphosphate (NTP) synthetisiert und charakterisiert, mit dem Ziel, die Limitierungen durch die Substratspezifität endogener Kinasen zu umgehen. Die intrazelluläre Aufnahme der anionischen NTP erfolgte über den SNT Transporter oder durch die Anwendung des TriPPPro Konzepts. Zudem wurden anorganisch organische Hybridnanopartikel (IOH NP) synthetisiert und umfassend charakterisiert, um deren Potenzial als zelluläre Nukleotid-Transporter zu untersuchen
Numerical simulation and experimental validation of NO emissions in a heavy-duty HDI engine considering injector needle dynamics and multi-cycle analysis
Get PDFHydrogen direct-injection engines offer a promising pathway for decarbonizing heavy-duty transportation, but accurate
prediction of mixture formation and NO emissions remains challenging due to complex injector dynamics and strong
cycle-to-cycle variability. This work presents a comprehensive computational and experimental investigation of supersonic
H direct injection, mixing, combustion, and NO formation in a single-cylinder heavy-duty hydrogen engine operated at
1100 rpm and λ = 2.6. A detailed three-dimensional CFD model is developed, coupling a pressure-based injection bound-
ary condition with a realistic Bosch F2 prototype injector needle-lift profile to capture valve-bounce effects. The model
is validated against measured in-cylinder pressure, fuel and air mass, and NO emission data. Multi-cycle combustion
behavior and NO emission variability are analyzed using the concurrent perturbation method (CPM), with 20 statistically
independent realizations at reduced computational cost. Results show that near-spark mixtures with higher fuel concentra-
tion accelerate flame propagation and increase peak NO by a factor of two (76 ppm vs. 32 ppm). Simulations reveal that
NO forms predominantly in local pockets of high fuel concentration, with turbulent flame speeds of 11–22 m/s during the
early combustion phase. Predicted exhaust-port NO levels agree qualitatively with experiments, though unsteady RANS
tends to overpredict NO due to limited small-scale mixing. The study demonstrates that resolving the injector flow rather
than approximating boundary conditions, combined with CPM can effectively capture hydrogen combustion dynamics
and emission variability
Signal model for the radio emission of inclined cosmic-ray air-showers and energy reconstruction of event candidates for GRAND
Get PDFUltra-high-energy cosmic rays (UHECRs) originate from the most energetic and mysterious environments in the Universe. When UHECRs reach Earth, they collide with nuclei in the atmosphere, and induce massive particle cascades. Due to their rarity, we can only measure them with large surface detectors. The Giant Radio Array for Neutrino Detection (GRAND) will, next to its main goal of measuring UHE neutrinos, also be especially sensitive to inclined air showers induced by UHECRs. I use CoREAS simulations of the radio emission of inclined air-showers to adapt a previously developed signal model for this phenomenon in the 30–80 MHz frequency band to the 50–200 MHz band used by GRAND. I tune the model for the site of the GRAND prototypes GRAND@Auger, located at the Pierre Auger Observatory in Argentina, and GRANDProto300 (GP300) in the Gansu province of China. I reconstruct the geomagnetic radiation energy by fitting a lateral distribution function to the radially symmetric distribution of the energy deposited in the ground. After I correct for the air-density and geomagnetic field dependence, I correlate the radiation energy with the electromagnetic shower energy. The radio emission of air-showers changes significantly depending on parameters like frequency, geomagnetic field, and observation altitude. With the modifications I introduce to the model, I expect it to be viable for any configuration of the geomagnetic field, as well as lower and higher frequency bands by simply retuning the model parameters. With this work, I provide the first end-to-end event reconstruction for GRAND, including the reconstruction of the electric field from measured data, as well as a solid basis for the analysis of future GRAND measurements. The reconstruction achieves an intrinsic energy resolution better than 5% for the sites of GRAND@Auger and GP300. I benchmark the reconstruction by simulating the sparse antenna layouts of GP300 and GRAND10k, a future stage of GRAND with a 10,000 km2 detection area. Under realistic measurement conditions, the reconstruction achieves an excellent energy resolution of 7% with vanishing biases for both detectors. The reconstruction shows no inherent dependence on the cosmic-ray primary particle. I successfully apply the energy reconstruction to six of the first GRAND cosmic-ray event candidates, measured by a partial configuration of GP300. The reconstructed energies agree with expectations. Furthermore, I study the detection efficiency of GP300 and GRAND10k. I estimate for both detectors the rate of detected and reconstructed cosmic ray events. I expect GP300 and GRAND10k, respectively, to measure about 2000 and 85,000 cosmic-ray events with energies > 1018 eV within one year of exposure time. I predict that a detector like GRAND10k will detect at least 10 UHECR events with energies > 1019.75 eV within the same time period
Superconducting high-power cables and lines – Development status and technology roadmap
No full textMore than 35 years after the discovery of high-temperature superconductivity and more than 20 years after the first field-test installation of a high-temperature superconducting cable, superconducting cables and lines were developed successfully up to high voltage levels and several long-term field tests demonstrated a reliable operation. There are many different applications where superconducting cables and lines were developed in the past. The technology readiness level is very different among the applications. Whereas medium voltage cables for urban areas with a length of a km have been field tested for long times in several locations, high voltage long distance cables are still in the technology concept status. This contribution is structured in four main parts. A proper description of superconducting cables cannot be made without an overview on the present material R&D and the lessons learned from the many successful projects in the past. Presently, there are substantial activities to further develop superconducting cables for AC and high-current DC applications and they are summarized in the second part. Recently, two start-up companies were founded and their R&D is also included. The third part of this paper covers the experience with a reliable operation and the cooling aspects. These contributions focus on the experience from field test applications and on future developments in this area. Hydrogen as an energy carrier is getting more and more attractive and due to the high energy density liquid hydrogen is expected to be widely used at least in some applications. This would favour the combination with superconductors very much because of its temperature of 20 K at pool boiling conditions. The last part of this contribution summarizes present R&D activities for hybrid energy lines with chemical and electricity transport in one line
Intermodale Verknüpfung von Fahrrad und Bahn im Landkreis Dahme-Spreewald: Analyse räumlicher Unterschiede und Potenziale
Get PDFIm Beitrag wird untersucht, wie gut Bahnhöfe im Landkreis Dahme-Spreewald mit dem Fahrrad erreichbar sind und welche Bedeutung sie im Netz haben. Auf Basis von Isochronenanalysen werden Einzugsgebiete ermittelt, mit Bevölkerungsdaten verschnitten und mit den Bahnhöfen in Verbindung gesetzt. Die Ergebnisse zeigen, dass 71 % der Bevölkerung des Landkreises einen Bahnhof innerhalb von 20 Minuten erreichen können. Es bestehen jedoch räumliche Unterschiede, die Hinweise auf intermodale Potenziale für die strategische Planung liefern
Atmospheric lifetime of sulphur hexafluoride (SF6) and five other trace gases in the BASCOE model driven by three reanalyses
Get PDFElectrode Thickness Optimization in Color-Selective Inkjet-Printed Photosensitive Organic Field-Effect Transistors †
Get PDFThis work introduces a general solution for printing wavelength-selective bulk-heterojunction photosensitive organic field effect transistors (PS-OFETs) by addressing electrode thickness variation and the feasibility of color selectivity in detecting incident light. The inkjet-printed silver electrode thickness was varied from 125 to 950 nm by multilayer printing. PIF, IDFBR, and ITIC-4F were chosen as the active semiconductor materials with complementary optical absorption. Results indicate that PS-OFETs exhibit the best functionality at an electrode thickness of approximately 325 nm and an active material combination with PIF:IDFBR (1:1). For the 540 nm wavelength, a responsivity of 55 mAW was obtained. This is four-fold higher than the photoresponse obtained at 700 nm
Review of weighting methods for life cycle impact assessment under GLAM
Get PDFPurpose
Weighting is the process of assigning relative importance to life cycle inventory results or indicator results across impact categories, using weighting factors based on value choices. It is an optional step within Life Cycle Assessment (LCA) but plays an important role in interpreting and communicating the relative importance of different environmental impacts. As part of the Global LCIA Guidance (GLAM) project under the UN Life Cycle Initiative, a comprehensive review of weighting methods was conducted to better understand which approaches are most appropriate for different applications in LCA.
Methods
Members of the GLAM weighting subtask identified and reviewed twenty-seven weighting methods. These methods were grouped into four categories: Multiple Criteria Decision Analysis (MCDA), monetary, data-driven and distance-to-target methods. Classifiers based on inherent features of the weighting methods were applied to support their inclusion or exclusion from further considerations. Each method then was assessed against a set of evaluation criteria defined by the subtask members. A color-code system (green, yellow or red) was applied to indicate the degree to which each method met each criterion to facilitate comparison and communication.
Results and discussion
Each method was briefly described with appropriate references, including examples of usage in LCA studies where available. The review results are summarized in a table that highlights the performance of each method against the evaluation criteria. All monetary methods are classified as trade-off rates, whereas there are MCDA methods and data-driven methods that can be either trade-off rates or importance coefficients. All distance-to-target methods are classified as importance coefficients. The ability of each method to incorporate temporal discounting or cultural differentiation varies, depending on the data availability and study design. None of the methods reviewed fully met all evaluation criteria, especially within the scope of the GLAM project. Some criteria (like Scientific validity) are sufficiently met by almost all of these methods.
Conclusions
Existing weighting methods based on different approaches have both advantages and limitations. No single method is universally sufficient, and their validity depends on context. This comprehensive overview of available weighting methods provides a valuable starting point for practitioners seeking to identify suitable weighting method for specific LCA applications. To facilitate easy use, a software was also developed based on this review to support the selection of the most appropriate weighting method for LCA studies
Biomechanical optimization of printing paths in Fused Filament Fabrication
Get PDFAdditive Manufacturing has progressed from rapid prototyping to producing functional components. Extrusion based processes like Fused Filament Fabrication (FFF) enable fast, cost-effective fabrication of complex geometries, particularly in small quantities. However, the layer-by-layer structure leads to orthotropic mechanical properties, with strength and stiffness highest along print direction and decreasing in deviating directions. Designing robust components thus requires accounting for anisotropy and optimizing the printing paths themselves. Computer Aided Internal Optimization (CAIO), inspired by tree growth, aligns orthotropic axes with local principal stress, to match material strength and load paths. For a tensile-loaded perforated plate, the resulting orientation of orthotropic axes was translated into printing paths. Optimized specimens printed out of Polylactic Acid showed up to 28 % higher tensile strength, compared to industry-standard printing patterns using the same material amount. The Soft Kill Option (SKO), based on bone growth principles, was applied for topology optimization, targeting minimal mass and maximum stiffness. SKO optimized specimens achieved 25 % weight reduction and a 5 % increase in tensile strength over industry-standard prints. Compared to standard specimens of equal mass, breaking loads increased by nearly 70 %. These results demonstrate that CAIO and SKO significantly enhance mechanical performance and suggest strong potential for manufacturing highly robust components