Gutenberg Open Science (Univ. Mainz)
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Reading nature and cultures : interdisciplinary perspectives on Witi Ihimaera’s “The Whale Rider” and its contexts
No full text237 Seite
Artificial intelligence and intelligent matter : nanoscience, soft matter, philosophy
Full text linkX, 509 Seite
Development of a 3D transparent aortic model as a radiation-free training simulator for basic skills of endovascular aortic interventions
No full textBackground
Endovascular aortic repair (EVAR) are gradually replacing open surgical repair for aortic diseases, due to their minimally invasive nature. These procedures require a high level of expertise that is gained through extensive clinical experience, posing risks such as prolonged radiation exposure. Training on 3D-printed simulation models can offer safer environment for learning & improve procedural precision & outcome.
Method
A single-center study to evaluate whether training on radiation-free three-dimensional (3D) printed aortic training models can reduce the time required from vascular surgeons to complete the basic endovascular navigation tasks, such as navigating the guide wire & probing the different branches. We involved 15 vascular doctors, 8 in-experienced (group1) & 7-experienced (group2). Participants received a 15-min lecture on aortic interventions and guide wire handling. Two self-made 3D printed training models were used. Models either are of the entire aorta (ascending to iliacs, see model1) or thoracoabdominal aorta (model2) were used. A covering box and a camera positioned above the aortic model that mirror the intervention on a monitor, simulating the indirect vision of the intraoperative fluoroscopy. Participants were required to probe and intubate four aortic branches (two renal arteries, coeliac trunk, & superior mesenteric artery) in three steps: initial assessment, 15-min training, & post-training assessment (next day). Task completion times were recorded & analyzed.
Results
Group1 initially required 914 ± 420 s to intubate four ostia, which significantly decreased to 149 ± 48 s post-training (p = 0.001). Experts showed no significant time reductions following the training (p = 0.443). Initial times were significantly lower for Group2 (p = 0.002), but post-training times showed no significant difference between both groups (p = 0.134).
Conclusion
Using 3D-printed models in a simulation-training may help to familiarize & train participants with endovascular aortic procedures within limited material costs, leading to significant reductions in task completion time among trainees. Additionally, a significant reduction in simulated visualization time was observed, suggesting potential for reduced fluoroscopy exposure in real procedures
Raw data for "Soil formation and weathering over the past 60 kyr reconstructed using lithium isotopes from Maar records"
Full text linkChemical weathering of silicate rocks is a fundamental control on the carbon cycle, although on timescales shorter than a few tens of kyr, transient carbon storage becomes more important. However, weathering can still act as an amplifier or inhibitor of the carbon cycle on these timescales. Further, weathering produces soils, a storage reservoir of carbon, although the rate at which soils can be produced is likely highly variable, and remains uncertain. Here, we use lithium isotopes in laminated maar sediments from western Germany to examine weathering and soil formation rates, principally across the rapid warming transitions of Greenland Interstadials (GI), also known as Dansgaard Oeschger (D/O) events, and rapid cooling of Greenland Stadials (GS). Our principal finding is that Li isotope ratios are higher during cooler periods, both on glacial-interglacial and GI-GS event scales. Thus, 7Li values average -2.5 ± 1.6‰ during GI events, and -1.5 ± 1.5‰ in the intervening colder stadial events. Based on the evolution of Li isotopes with weathering, this suggests that there was more soil formation relative to primary mineral dissolution during cooler compared to warmer events. That is not to say that weathering rates were higher, but that clay formation was amplified relative to a given weathering rate when it was cooler, due to the combination of lower erosion rates, thermodynamically favoured conditions for clay formation, and enhanced water-rock contact times, promoting secondary mineral formation. Overall, the data show that soil formation responds even through rapid (~100 years) climate change events.Eifel, GermanyObservatio
Technische Umsetzung der gemeinsamen Lehrveranstaltungen
No full textDie Micromodule sind von den Studierenden mit synchronen und nicht synchronen Elementen zu absolvieren. Sie müssen wartungsfreundlich und gleichzeitig hochverfügbar, verlässlich und in Bezug auf darstellbare Medien vielfältig sein. In GeLb-DIng wurden daher verschiedene Wege zur technischen Umsetzung erprobt und evaluiert
Programmable self-destruction of artificial cells with death signaling
No full textProgrammed cell death is a crucial biological process that removes damaged or no longer needed cells and is orchestrated through complex intracellular signaling cascades. Mimicking such behavior in synthetic systems enables programmed disassembly after completing a task or releasing cargo on demand. Despite advances in engineering artificial cells (ACs) that mimic key cellular functions such as metabolism, homeostasis or communication, systems with a programmable lifetime remain unrealized. Here, we introduce a time-programmed self-destruction mechanism in ACs based on pH-responsive giant unilamellar vesicles, equipped with an internal UV-inducible acidification cascade. Upon light activation, photocaged glucose is enzymatically converted to gluconic acid, lowering the internal pH and destabilizing the pH-sensitive membrane, ultimately causing complete membrane collapse. The self-destruction is spatially confined and tunable in time, ranging from minutes to over an hour, depending on the light intensity. Furthermore, we demonstrate that collapse-induced release of DNA signals triggers defined downstream responses in neighboring ACs, including membrane labeling and aggregation. Our findings pave the way for ACs with programmed lifetimes, capable of on-demand release or disassembly in response to defined stimuli, allowing transmission of signals within complex synthetic environments
Ein neuer, schneller Bioassay als Biomarker für Endokrine Orbitopathie
No full textZiel dieser Dissertation ist es, den klinischen Nutzen des Turbo TSI-Assays als sensitiven und funktionellen Bioassay für die Diagnostik und Verlaufsbeurteilung von Morbus Basedow und der endokrinen Orbitopathie zu untersuchen. Dabei sollen die Daten des Turbo TSI anhand eines Kollektivs mit den Ergebnissen eines TRAK Bindungsassays und eines TSI Bioassays verglichen und die Korrelation mit klinischen Parametern analysiert werden. Darüber hinaus wird der Effekt eines Anti-FcRn-Antikörpers auf die Antikörpertiter betrachtet. Die Ergebnisse dieser Arbeit könnten dazu beitragen, die Diagnostik und Therapie von Autoimmunthyreopathien weiter zu optimieren und die Messung von TRAK mittels Bindungsassay mit einem neuen effizienten Assay um die Messung von TSI zu ergänzen oder vielleicht sogar in der Zukunft abzulösen.IV, 67 Seiten ; Illustrationen, Diagramm
A calorimetric wire detector for measurement of atomic hydrogen beams
No full textThe Project 8 collaboration aims to determine the absolute neutrino mass
with a sensitivity of 40 meV by measuring the tritium decay spectrum. Project 8 will use atomic tritium confined in a magnetic trap to perform CRES on decay electrons produced directly in the trap and performing cyclotron motion in the same magnetic field.
Reaching the desired sensitivity will require the observation of a large number of tritium decays, since a tiny fraction (\qty{e-13}) of all decays produce an electron sufficiently close to the endpoint to be informative for the neutrino mass.
Additionally, since molecular tritium sensitivity receives a large statistical penalty to energy resolution caused by the molecular final state distribution, atomic tritium must be used for the desired sensitivity.
Project 8 must develop an atomic tritium beamline capable of injecting into the CRES detection volume. Due to losses in cooling, injection, and trapping, we anticipate that this will require an atomic tritium source that initially produces an atom flux of . The development of such a source is currently underway, and a candidate, the HABS, is used for measurements presented in this thesis.
This thesis focuses on the development of a calorimetric wire detector capable of measuring the intensity and distribution of atomic hydrogen beams as required by Project 8.
The detector uses a wire with a micrometer-scale diameter intersecting the beam on which a small fraction of the beam's hydrogen atoms recombine into molecules. The energy released heats
the wire and produces a measurable change in its resistance.
We present measurements performed with such a detector to determine the distribution of hydrogen atoms across a beam produced by the test source, and present limits on the total flux of atoms that are produced by this source. We also present a theoretical description of the wire detector, including a simulation.
The results directly contributed to a better understanding of the HABS showing the utility of the calorimetric wire detector in further development of the atomic tritium beamline.V, 135 Seiten ; Illustrationen, Diagramm
Does Ramadan fasting influence time-motion metrics and psychophysiological responses in soccer players during small-sided games performed in fed and fasted states?
Full text linkWe explored how Ramadan fasting (RF) influences GPS-derived time-motion metrics and psychophysiological responses in soccer players during small-sided games (SSG). Twelve semi-professional male players (mean age 21.1 ± 0.7 y; estimated V ̇ O2max 54.5 ± 2.2 mL/min/kg) participated in four experimental SSG sessions in a within-subject, counterbalanced design. These sessions were scheduled at 15:00 and 21:00 before Ramadan, in a fed state (i.e., BR15fed and BR21fed), and during the fourth week of Ramadan at 15:00 in a fasted state (DR15fasted) and at 21:00 in a fed state (DR21fed). Sleep patterns, dietary intake, and insomnia symptoms were evaluated during the week preceding and final week-of-Ramadan. Participants’ Hooper index (wellness) and daytime sleepiness and mood measures were assessed before each session. Time-motion metrics using GPS and exercise heart rate (HR) were assessed during all sessions, and ratings of perceived exertion (RPE) were collected after each session. Except for a higher number of decelerations in DR21fed session (p < 0.001), RF had no significant effect on other time-motion metrics. Absolute and relative exercise HR were higher at BR15fed than at BR21fed and at DR15fasted. RPE, Hooper index scores, and perceptual stress and muscle soreness components were higher at DR15fasted compared to BR15fed. Additionally, RF was associated with decreased sleep duration (by ~45 minutes) and increased insomnia symptoms and daytime sleepiness, while mood states and dietary intake were unchanged. RF induced physiological and perceptual changes in response to exercise, particularly in the fasted state. However, SSG performance metrics remained stable, suggesting fasted athletes can maintain short-duration SSG performance regardless of fasting status
Conversion of novel bimetallic metal organic frameworks into hierarchically structured electrocatalysts for high performance hydrogen evolution
Full text linkDeveloping economically viable and high-performance electrocatalysts for the hydrogen evolution reaction (HER) is crucial for achieving sustainable hydrogen production. However, achieving a combination of high catalytic activity and long-term stability remains a challenge. In this study, we report the development of hierarchically porous hollow Co–Ni doped carbon electrocatalysts synthesized via pyrolysis. The optimized CoNi-MOF@850 °C catalyst exhibited excellent HER kinetics in alkaline media, requiring only 148 mV overpotential at 10 mA cm−2 with a Tafel slope of 65 mV dec−1, surpassing the monometallic Co and Ni catalysts and approaching the performance of the commercial Pt/C (95 mV, 43 mV dec−1). Notably, when employed in an AEM electrolyzer, the CoNi-MOF@850 °C catalyst maintained ∼96% potential retention over 100 h at 200 mA cm−2, demonstrating an exceptional stability. The synergistic interaction between Co and Ni, combined with the hierarchical porous structure, enhances electronic conductivity, increases active site density, and facilitates efficient charge transfer, leading to the observed superior catalytic performance. These results demonstrate the potential of bimetallic MOF-derived catalysts as cost-effective and sustainable alternatives to noble-metal-based electrocatalysts for large-scale green hydrogen production technologies