Gutenberg Open Science (Univ. Mainz)
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Verbesserung des pulmonalen Outcomes bei Patienten mit Oberbaucheingriffen mittels präoperativer atemtherapeutischer Schulung und Elektrischer Impedanztomographie (EIT) als Biofeedback
No full textXVII, 80 Seiten ; Illustrationen, Diagramm
Synthesis, structures, chemical bonding, and properties of Al9–xFexMo3 with 0.5 ≤ xFe ≤ 1.8
No full textWe report the crystal structure and properties of the Al9–xFexMo3 phases. Samples with nominal xFe content up to 2.5 were synthesized by arc-melting and annealed at 600 °C. The products were analyzed by ex situ and in situ X-ray diffraction, and the phase compositions were determined. The crystal structures of the ternary phases were refined at room temperature. The τ1 phase, Al8.5Fe0.5Mo3, crystallizes in the tetragonal Al3Ti type of structure, whereas an orthorhombic distorted structure is observed for Al9–zFezMo3 with 1.0 ≤ zFe ≤ 1.8. At temperatures around ≈300 °C, a reversible orthorhombic ↔ tetragonal phase transition occurs. The τ2 phase (disordered W-type of structure) is metastable at room temperature and decomposes above ≈425 °C into the Fe-enriched orthorhombic Al9–zFezMo3 phase, AlFe, and AlMo3. DFT calculations of the formation energies of FeAl substitution are reported, and aspects of chemical bonding in Al9–xFexMo3 are provided (DOS, COHP, and ELF). The physical properties are investigated by 57Fe-Mössbauer spectroscopy and magnetic measurements, indicating spin glass behavior at low temperatures
A Lanczos-based method for computing Ornstein-Uhlenbeck representations for the generalized langevin equation
Get PDFThe generalized Langevin equation describes the velocity of a macromolecule via the convolution of the history of its velocity and a memory kernel. It employs the coarse graining approach of only simulating the macromolecule's velocity explicitly while collisions with other particles are modeled via a random force process. If the memory is a Prony series, it can be represented by an Ornstein-Uhlenbeck process by introducing auxiliary variables.
We are interested in the inverse problem, which consists in determining a good approximation of the memory kernel given the covariance function of the velocity. We present a new method for solving this problem. Instead of first approximating the memory kernel in order to determine a suitable Prony series and an Ornstein-Uhlenbeck process approximation, this method directly yields an Ornstein-Uhlenbeck process which approximates the given velocity covariance function. It is based on a variant of the (multi-dimensional) Lanczos algorithm followed by several post-processing steps and can also be applied to the multi-dimensional generalized Langevin equation.
We test this method using data from molecular dynamics simulations. For the one-dimensional case we introduce an extension of the algorithm for the setting where the macromolecule is subject to an additional constant external force.Die verallgemeinerte Langevin-Gleichung beschreibt die Geschwindigkeit eines Makromoleküls mithilfe der Faltung des Verlaufs der Geschwindigkeit mit einem Gedächtniskern. Sie verwendet einen "coarse graining" genannten Ansatz, indem nur die Geschwindigkeit des Makromoleküls explizit simuliert wird, während Kollisionen mit anderen Partikeln durch einen stochastischen Prozess für die Kraft dargestellt werden. Wenn der Gedächtniskern eine Prony-Reihe ist, kann man Hilfsvariablen einführen, um sie durch einen Ornstein-Uhlenbeck-Prozess darzustellen.
Wir interessieren uns für das inverse Problem, welches darin besteht, zu einer gegebenen Kovarianzfunktion der Geschwindigkeit eine gute Approximation des Gedächtniskerns zu bestimmen. Wir stellen eine neue Methode zur Lösung dieses Problems vor. Anstatt zuerst den Gedächtniskern zu approximieren, um anschließend eine geeignete Prony-Reihe und eine Approximation durch einen Ornstein-Uhlenbeck-Prozess zu bestimmen, konstruiert diese Methode direkt einen Ornstein-Uhlenbeck-Prozess, der die gegebene Kovarianzfunktion approximiert. Sie basiert auf einer Variante des (mehrdimensionalen) Lanczos-Algorithmus, gefolgt von mehreren weiteren Schritten, und kann auch auf die mehrdimensionale verallgemeinerte Langevin-Gleichung angewendet werden.
Wir testen diese Methode mit Daten aus Molekulardynamik-Simulationen. Für den eindimensionalen Fall führen wir eine Erweiterung des Algorithmus für die Situation ein, in der das Makromolekül von einer zusätzlichen konstanten externen Kraft beeinflusst wird.viii, 109 Seiten ; Diagramm
The cognitive style of ChatGPT
Get PDFAI might not outperform humans after all, but simply mirror our evolving metrics of value. When researchers pitted elite design students against ChatGPT in creating product ideas for college life, the AI consistently won by generating concepts that were familiar rather than revolutionary. What appears as superiority exposes how our information environment increasingly rewards immediate plausibility over thoughtful reflection. The real insight isn't about machine intelligence, but about how our evaluation systems are quietly reshaping human thinking itself—privileging the recognizable over the nuanced and thought provoking
Remodellierung des rechten Herzens und klinische Ergebnisse bei Patienten mit Trikuspidalinsuffizienz: Eine Literaturübersicht und Metaanalyse
Get PDFBACKGROUND
Functional tricuspid regurgitation (TR) can develop either because of right ventricular (RV) remodeling
(ventricular functional TR) and/or right atrial dilation (atrial functional TR).
OBJECTIVES
This meta-analysis aimed to investigate the association between right heart remodeling and long-term
(>1 year) all-cause mortality in patients with significant TR (at least moderate).
METHODS
MEDLINE, ISI Web of Science, and SCOPUS databases were searched. Studies reporting data on at least 1 RV
functional parameter and long-term all-cause mortality in patients with significant TR were included. This study was designed according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) requirements.
RESULTS
Out of 8,902 studies, a total of 14 were included, enrolling 4,394 subjects. The duration of follow-up across
the studies varied, ranging from a minimum of 15.5 months to a maximum of 73.2 months. Overall, long-term all-cause mortality was 31% (95% CI: 20%-41%; P < 0.001). By means of meta-regression analyses, an inverse relation was found between tricuspid annular plane systolic excursion (11 studies enrolling 3,551 subjects, -6.3% [95% CI: -11.1% to -1.4%]; P = 0.011), RV fractional area change (9 studies, 2,975 subjects, -4.4% [95% CI: -5.9% to -2.9%]; P < 0.001), tricuspid annular dimension (7 studies, 2,986 subjects, -4.1% [95% CI: -7.6% to -0.5%]; P = 0.026), right atrial area (6 studies, 1,920 subjects, -1.9% [95% CI: -2.5% to -1.3%]; P < 0.001) and mortality.
CONCLUSIONS
RV dysfunction parameters are associated to worse clinical outcomes in patients with TR, whereas right
atrial dilatation is linked to a better prognostic outcome. Further studies are needed to unravel the pathophysiological differences within the functional TR spectrum.getrennte Zählung ; Illustrationen, Diagramm
The nine dragon tree conjectures
Get PDFThis thesis deals with the Nine Dragon Tree conjectures, which concern partitioning the edge set of a graph into as few forests as possible while ensuring that one of the forests is as "sparse" as possible.
The well-known Nash-Williams Theorem states that the edge set of a loopless graph G can be partitioned into k forests if
γ(G) := \max_{H \subseteq G, v(H) > 1} e(H)/(v(H) - 1) <= k.
Thus, \ceil{γ(G)} is the minimum number of forests into which E(G) can be partitioned. The Nine Dragon Tree Theorem generalizes this relationship: if k, d \in N and γ(G) <= k + d/(d+k+1), then G admits a decomposition into k+1 forests, where one of the forests F has maximum degree at most d. The Strong Nine Dragon Tree Conjecture even states that a decomposition can be found in which each tree of F contains at most d edges.
While the Nine Dragon Tree Theorem has already been proven, its strong variant remains open in most cases. In this thesis, we prove it for d <= 2(k+1) and show an approximation for the remaining cases in which the sizes of the connected components are bounded by O(d^2/k).
We also show that, as conjectured by Kim, Kostochka, West, Wu, and Zhu, there exists a weaker density condition that still implies the stated decompositions.
Analogous conjectures can be formulated for pseudoforests, for which even the strong variant has already been proven.
In this thesis, we show that an even stronger decomposition is possible in which one of the pseudoforests F is actually a forest, and its diameter can be further restricted. We prove that the diameter bounds we establish are best possible, in the case that F is also required to have its degree bounded above by any constant.
We further show that, as in the case of the Nine Dragon Tree conjectures for forests, a weaker density condition exists for the pseudoforest variants that also allows us to achieve the additional diameter bounds.viii, 169 Seiten ; Illustratione
Multiple-Reflection Time-of-Flight Mass Spectrometer (MR-ToF MS) enhanced in-gas-jet Laser Spectroscopy of the Heavy Actinides
Get PDFLaser spectroscopy is a versatile tool to study the atomic structure and properties of exotic nuclei with high effciency and sensitivity. Electronic states of atoms can be excited via illumination with monochromatic, resonant laser light. In this work, the identifcation of excited atoms is done by either observation of their fluorescence emitted when relaxing back to an energetically lower state (light induced fluorescence, LIF), or by ionization of the atom via multi-step excitation (resonant ionization spectroscopy, RIS). This thesis presents some recent developments and applications of the JetRIS setup, a setup designed for laser spectroscopy in a gas jet. Within the context of this work, laser spectroscopy was utilized to characterize its spectral resolution, an atomic transition of 254No, multiple resonances of natSm, hyperfne components and isotope shifts and to test multiple technical developments necessary for studying on-line produced nuclides with the JetRIS setup.
A crucial part of the JetRIS setup is the nozzle and the corresponding gas jet formation. Here, the performance in terms of spectral linewidth was characterized utilizing LIF via laser excitation of Dy I using a 4f 106s2 → 4f106s6p transition at λ = 404.5nm. The spatially resolved fluorescence in dependence of the laser excitation frequency was recorded and a maximum average resolution of Δν = 212(30)MHz was obtained. JetRIS was then used in on-line experiments at the GSI facility in Darmstadt, utilizing two-step RIS and α-decay based detection measuring the 1S0→ 1P1 transition of 254No. The centroid of the transition was determined with ν = 29 961.480(12) cm−1 while a resolution of Δν = 770(300)MHz was achieved.
The last part of the thesis is dedicated towards RIS of samarium using ToF based detection utilizing and characterizing a Multiple-Reflection Time-of-Flight Mass Spectrometer (MR-ToF MS). Here six different First Excitation Step (FES) transitions were characterized, determining their mass and field shifts, as well as the hyperfine parameter A for the isotopes 147Sm and 149Sm. For five FES transitions, two Auto-Ionizing (AI) transitions were identified each, while for the remaining FES transition, only one AI transition was found. Utilizing the isotope 154Sm, the mass resolving power R, the relative effciency ϵ and the capability of in-trap-deflection of the MR-ToF MS was characterized. The MR-ToF MS will be integrated into the JetRIS setup, to enhance its detection capabilities for future on-line studies using a linear Paul trap as a radiofrequency (RF) cooler buncher. The cooler buncher and merging of both setups are planned for future work.Die Laserspektroskopie ist ein vielseitiges Werkzeug, um die atomare Struktur und Eigenschaften exotischer Kerne mit hoher Effzienz und Empfndlichkeit zu untersuchen. Elektronische Zustände von Atomen können durch Bestrahlung mit monochromatischem, resonantem Laserlicht angeregt werden. In dieser Arbeit erfolgt die Identifizierung angeregter Atome entweder durch Beobachtung ihrer Fluoreszenz, die beim Zurückfallen in einen energetisch niedrigeren Zustand emittiert wird (lichtinduzierte Fluoreszenz, LIF), oder durch Ionisierung des Atoms mittels mehrstufiger Anregung (resonante Ionisationsspektroskopie, RIS). Diese Arbeit stellt einige Neuerungen und Anwendungen des JetRIS vor, eines Versuchsaufbaus, welcher für die Laserspektroskopie in einem Gasstrahl entwickelt wurde. Im Rahmen dieser Arbeit wurde die Laserspektroskopie genutzt, um seine spektrale Auflösung, einen atomaren Übergang von 254No, mehrere Resonanzen von natSm, Hyperfeinkomponenten und Isotopieverschiebungen zu charakterisieren und mehrere technische Entwicklungen zu testen, die für die Untersuchung von beschleunigerproduzierten Nukliden mit dem JetRIS-Aufbau erforderlich sind. Ein wesentlicher Bestandteil des JetRIS ist die Düse und die entsprechende Gasstrahlbildung. Hier wurde die Leistung in Bezug auf die spektrale Linienbreite unter Verwendung von LIF durch Laseranregung von Dy I eines 4f106s2 → 4f106s6p Übergangs bei λ = 404.5nm charakterisiert. Die räumlich
aufgelöste Fluoreszenz wurde in Abhängigkeit der Laseranregungsfrequenz aufgezeichnet und eine maximale durchschnittliche Auflösung von Δν = 212(30)MHz erzielt. Anschlieÿend wurde JetRIS in Beschleunigerexperimenten an der GSI in Darmstadt eingesetzt, um zweistufige RIS in Kombination mit α Zerfall Detektion verwendet wurde, um den Übergang von 1S0→ 1P1 in 254No zu messen. Der Schwerpunkt des Übergangs wurde mit ν = 29 961.480(12) cm−1 bestimmt, während eine Auflösung von Δν = 770(300)MHz erreicht wurde.
Der letzte Teil der Arbeit widmet sich der RIS von Samarium unter Verwendung einer ToF basierten Detektion unter Einsatz und Charakterisierung eines Mehrfachreflexionsflugzeitmassenspektrometers (MR-ToF MS). Hier wurden sechs verschiedene erste Anregunsschritte (FES) charakterisiert und ihre Masse- und Feldverschiebungen sowie der Hyperfeinparameter A für die Isotope 147Sm und 149Sm bestimmt. Bei fünf FES wurden jeweils zwei Autoionisationsübergänge (AI) identifiziert, während bei dem verbleibenden FES nur ein AI gefunden wurde. Mit Hilfe des Isotops 154Sm wurden das Massenauflösungsvermögen R, die relative Effzienz ϵ und die Fähigkeit zur in-trap-Ablenkung des MR-ToF-MS charakterisiert. Das MR-ToF MS wird in den JetRIS-Aufbau integriert, um dessen Detektionsfähigkeiten für zukünftige Experimente unter Verwendung einer linearen Paulfalle als Radiofrequenz (RF) cooler buncher zu verbessern. Der cooler buncher und die Kombinierung beider Aufbauten sind Teile zukünftiger Arbeiten.x, 81 Seiten ; Illustrationen, Diagramm
Helicobacter pylori, gastric cancer and socioeconomic factors in an urban area: Evaluating the strengths and limitations of spatial analysis
Get PDFObjective:
Spatial epidemiology provides a valuable opportunity to utilize routinely collected clinical data for analyzing disease distribution. This study evaluates the potential of such data to model the geographical distribution of Helicobacter pylori (H. pylori) colonization and gastric cancer in Mainz, Germany. We aimed to assess the feasibility of spatial statistical analyses of clinical routine data, identify factors influencing H. pylori colonization, and investigate whether H. pylori colonization and gastric cancer share common spatial patterns and risk factors relevant for prevention strategies.
Methods:
Data on H. pylori colonization was extracted from routine gastric biopsy reports (2008–2019), while gastric cancer cases were derived from local cancer registry data (2019–2022). Geospatial data and socioeconomic variables were integrated into generalized linear mixed-effects models (GLMMs) to explore their associations with the diseases. The Moran's I statistic was used to assess spatial autocorrelation.
Results
Among 19,727 biopsies analyzed, 24.7 % were H. pylori-positive, with colonization varying widely across districts (10.7 %–38.9 %). Significant associations were found with unemployment rates, household size, and foreign or immigrant background populations. In contrast, the GLMM for gastric cancer revealed no significant predictors, likely due to low case numbers (108 cases) and limited variation across districts. Nonetheless, the observed association between H. pylori and gastric cancer aligns with established literature.
Conclusions:
This study demonstrates the potential of routine data in spatial epidemiology for identifying at-risk populations. While challenges remain, particularly for rarer diseases, this approach provides valuable insights into disease distributions and can support targeted prevention strategies
Climate and parasite pressure jointly shape traits mediating the coevolution between an ant social parasite and its host
Get PDFHost–parasite relationships are often shaped by coevolutionary arms races. While abiotic influences on these dynamics are well documented, a combined analysis of abiotic and biotic factors is essential for understanding coevolution, particularly under climate change. In this study, we analysed the interactions of the obligate social parasite Temnothorax americanus, a dulotic ant, and its primary host, the ant T. longispinosus, focusing on behavioural and cuticular hydrocarbon (CHC) traits that govern parasite invasion and host defence. We studied the link between these traits and local climate as well as parasite prevalence. Our results revealed that behavioural interactions were more strongly associated with climate than parasite prevalence. Hosts from warmer, drier regions exhibited reduced aggression during parasite encounters, opting to pick up the brood and flee, while parasites from these regions exhibited greater aggression and activity. CHCs mediating enemy recognition in these ants were linked to local climate and parasite prevalence in both species. As all colonies were maintained under standardized conditions for a year, we attribute the observed phenotypic traits to evolutionary adaptation rather than phenotypic plasticity. Our findings suggest that both abiotic and biotic factors play critical roles in shaping co-evolving traits, sometimes leading to unexpected patterns that would potentially be overlooked when considering only a single factor. These insights provide a framework for understanding how climate influences coevolution of interacting species
Prognostic value of blood-based biomarkers in multiple sclerosis patients in the absence of clinical relapses or new MRI lesions
Get PDFBackground:
In multiple sclerosis (MS), an increase in whole-brain lesion volume (LV) on MRI can be observed even in the absence of newly demarcated focal lesions or clinical relapses. However, it is unknown whether the presence of increasing LV alone is enough to justify changes in the therapeutic regimen. At this point, blood-based biomarkers may aid to identify patients at risk for progression.
Objective:
To determine the prognostic value of blood-based biomarkers (serum neurofilament (sNfL) and serum glial fibrillary acidic protein (sGFAP)) on disability progression in MS patients without newly demarcated lesions or clinical relapses.
Design:
Longitudinal cohort study.
Methods:
In total, out of 291 MS patients who were retrospectively screened for this study, 171 patients underwent a detailed clinical and MRI assessment and were finally included in the analysis: 100 patients with increasing LV (mean baseline Expanded Disability Status Scale (EDSS) = 1.5) and 71 with stable LV over 2 years (mean baseline EDSS = 1.0). Baseline blood-based measures (sNfL and sGFAP) and MRI metrics (total T2-weighted LV, gray matter (GM) volume) were acquired. EDSS worsening served as a clinical outcome measure and was determined through a 2-year follow-up. Receiver operator characteristic analyses were conducted to determine the predictive discriminative power of both blood-based biomarkers. Multivariate logistic regressions were performed to identify independent risk factors for EDSS progression in both cohorts.
Results:
MS patients with increasing LV had lower GM volume (p = 0.0109, q = 0.0490) and worse EDSS scores (p = 0.0065, q = 0.0650) at clinical follow-up compared to patients with stable LV. Patients with increasing LV and EDSS progression had significantly higher sNfL (p = 0.0049, q = 0.0196), but not sGFAP (p = 0.7425, q = 0.9900) levels. In the logistic regression model, sNfL levels remained an independent risk factor for EDSS progression in patients with increasing LV (odds ratio = 1.344, 95% confidence interval: 1.038–1.739, p = 0.025), but not in patients with stable LV. Finally, in patients with increasing LV, sNfL levels, but not sGFAP levels, discriminated progressive from non-progressive MS patients upon clinical follow-up (area under the curve = 0.67, p = 0.004; q = 0.016).
Conclusion:
sNfL enhances the prediction of disease progression in MS patients with merely increasing LV on MRI but no new T2 lesions or other signs of inflammatory activity. These findings may support treatment decisions in seemingly stable patients