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On the Correctness of Maximum Parsimony for Data with Few Substitutions in the NNI Neighborhood of Phylogenetic Trees
Get PDFEstimating phylogenetic trees, which depict the relationships between different species, from aligned sequence data (such as DNA, RNA, or proteins) is one of the main aims of evolutionary biology. However, tree reconstruction criteria like maximum parsimony do not necessarily lead to unique trees and in some cases even fail to recognize the “correct” tree (i.e., the tree on which the data was generated). On the other hand, a recent study has shown that for an alignment containing precisely those binary characters (sites) which require up to two substitutions on a given tree, this tree will be the unique maximum parsimony tree. It is the aim of the present paper to generalize this recent result in the following sense: We show that for a tree T with n leaves, as long as k9k-11+9k2-22k+17, which in particular holds for all n≥12k), the maximum parsimony tree for the alignment containing all binary characters which require (up to or precisely) k substitutions on T will be unique in the NNI neighborhood of T and it will coincide with T , too. In other words, within the NNI neighborhood of T , T is the unique most parsimonious tree for the said alignment. This partially answers a recently published conjecture affirmatively. Additionally, we show that for n≥8and for k being in the order of n2, there is always a pair of phylogenetic trees T and T′which are NNI neighbors, but for which the alignment of characters requiring precisely k substitutions each on T in total requires fewer substitutions on T′
Motiviert lernen und sich dabei wohl fühlen? Die Auswirkungen der Leistungsmotivation von Schüler:innen auf ihr psychisches und physisches Wohlbefinden im Verlauf eines Schuljahres
Get PDFStudents’ motivation and well-being are not only highly relevant for success at school, they also facilitate students’ inherent growth, optimal functioning, and health. However, both motivation and well-being tend to decline over the school year, presenting a risk for students’ academic achievement and health. Although both constructs are closely related, longitudinal evidence of their relationship is still lacking. Following achievement goal theory and the broaden-and-build theory of positive emotions, it is the goal of the current study to explore how achievement goal-orientation is related to students’ physical and psychological well-being. A total of 733 seventh- and eighth-grade students (MAge = 14.73, SD = 0.69; 52% girls) participated in the study, completing the questionnaire once at the beginning and again at the end of the school year. By applying path analysis in Mplus, this study shows that students who tend to exhibit an avoidance goal orientation at the beginning of the school year tend to report lower levels of psychological and physical well-being at the end of the school year. Students who exhibit appearance performance approach goals reported higher levels of physical well-being at the end of the school year. Results also indicate that boys tend to report higher physical and psychological well-being at both time points.Die Motivation und das Wohlbefinden von Schüler:innen (SuS) sind nicht nur für den schulischen Erfolg von großer Bedeutung, sondern fördern auch das innere Wachstum, die optimale Funktionsweise und die Gesundheit. Allerdings nehmen die Motivation sowie das Wohlbefinden tendenziell im Laufe des Schuljahres ab, was ein Risiko für den schulischen Erfolg und die Gesundheit der SuS darstellt. Obwohl beide Konstrukte eng miteinander verbunden sind, fehlt es bislang an längsschnittlichen Studien zum Zusammenhang von Motivation und Wohlbefinden. Basierend auf der Theorie der Lern- und Leistungsmotivation und der „broaden-and-build“ Theorie positiver Emotionen untersucht die vorliegende Studie, wie die Leistungsmotivationsorientierung mit dem physischen und psychischen Wohlbefinden der SuS zusammenhängt. Insgesamt nahmen 733 SuS der siebten und achten Klasse (MAlter = 14,73, SD = 0,69; 52 % Mädchen) an der Studie teil und füllten den Fragebogen sowohl zu Beginn als auch am Ende des Schuljahres aus. Die Ergebnisse einer Pfadanalyse in Mplus zeigen, dass SuS, die zu Beginn des Schuljahres eine Vermeidungsmotivationsorientierung aufweisen, am Ende des Schuljahres ein tendenziell niedrigeres psychisches und physisches Wohlbefinden berichten. SuS, die eine Annäherungs-Leistungszielorientierung (performance-approach goal orientation) berichten, zeigen ein höheres physisches Wohlbefinden am Ende des Schuljahres. Die Ergebnisse zeigen auch, dass Jungen tendenziell zu beiden Zeitpunkten ein höheres physisches und psychisches Wohlbefinden berichten
High nitrate and sulfate leaching in response to wetter winters in temperate beech forests
Get PDFClimate models project moderate to large increases in air temperature for most temperate ecosystems with an overall increase in winter precipitation and a shift from snow towards rain. We investigated the effects of increased winter rainfall on the ecosystem functioning of European beech forests at their north-eastern distribution range. In a large-scale field experiment we manipulated winter climate at nine forest sites by increasing the amount of rainfall and excluding snow. Nutrient availability in the topsoil and leaching in 50 cm depth as well as litter decomposition and radial growth of mature European beech trees were analysed. It was hypothesized that (1) wetter winters lead to increased nutrient deposition as well as leaching, with an overall increase in net nutrient availability, (2) decomposition decreases in response to water addition containing also additional nutrients and (3) primary production during the subsequent growing season increases as presumably not all additionally available nutrients would be leached. We found an increase in topsoil nitrate and sulfate availability during winter in response to rain addition, likely as a consequence of collecting more atmospheric deposition, and surprisingly high leaching rates of the additionally available nutrients. During the subsequent early growing season, no difference in nutrient availability could be observed anymore. Enhanced nutrient availability in the topsoil and leaching do not seem to have a strong short-term influence on forest ecosystem processes in ecosystems which are close to their critical load of N deposition. Decomposition rates during winter and early growing season as well as stem diameter growth during the following growing season were not influenced. This indicates that additional nutrients in the topsoil in response to wetter winters are not available for plant growth but pollute ground- and surface waters
The Role of –OEt Substituents in Molybdenum-Assisted Pentathiepine Formation—Access to Diversely Functionalized Azines
Get PDF1,2,3,4,5-pentathiepines (PTEs) are naturally occurring polysulfides of increasing scientific interest based on their identified pharmacological activities. Artificial PTEs with N-heterocyclic backbones are efficiently synthesized via mediation by a molybdenum–oxo-bistetrasulfido complex. A common feature of all precursor alkynes successfully used to date in this reaction is the presence of a –CH(OEt)2 group since the previously postulated mechanism requires the presence of one OEt– as the leaving group, and the second must become a transient ethoxonium moiety. This raised the question of whether there really is a need for two, maybe only one, or possibly even zero ethoxy substituents. This research problem was systematically addressed by respective variations in the precursor-alkyne derivatives and by employing one related allene species. It was found that the total absence of ethoxy substituents prevents the formation of PTEs entirely, while the presence of a single ethoxy group results in the possibility to distinctly functionalize the position on the resulting N-heterocyclic pyrrole five ring in the target compound. This position was previously exclusively occupied by an –OEt for all products of the molybdenum-mediated reaction. The allene was applied with similar success as precursor as with the related alkyne. The now-employable significant change in precursor composition gives access to a whole new PTE subfamily, allowing further modulation of (physico)-chemical properties such as solubility, and provides additional insight into the mechanism of PTE formation; it comprises a merely partial validation of the previous hypothesis. The new alkyne precursors and pentathiepines were characterized by a variety of instrumental analyses (NMR, mass spec, UV–vis) and in six cases (one alkyne precursor, one unexpected side product, and four PTEs) by single-crystal X-ray diffraction. Syntheses, isolation procedures, analytical data, and the impact of the findings on the previously proposed mechanism are described in detail herein
Selective Enzymatic C−H‐Oxyfunctionalization for the Efficient Synthesis of Grevillic Acid
Get PDFIn this study, a selective C−H‐oxyfunctionalization using an unspecific peroxygenase (UPO) enabled an efficient biosynthetic route for the synthesis of grevillic acid (GA), a natural antioxidant. The route commenced with the release of o‐coumaric acid (oCA) from trans‐2‐coumaric acid glucoside (trans‐CAG) using commercially available β‐glucosidase from almonds. In addition, a cis‐to‐trans photoisomerization of cis‐CAG was implemented to increase the synthetic access of oCA. The key step, the para‐hydroxylation relative to the existing hydroxyl group of oCA, was accomplished by an UPO with full conversion and 93% isolated yield. Despite its name, the UPO turned out to exhibit excellent regioselectivity in this C−H functionalization, requiring only H2O2 as a cosubstrate
Sex‐Dependent Effects of CYP2D6 on the Pharmacokinetics of Berberine in Humans
Get PDFAn over‐the‐counter product berberine (a major alkaloid in goldenseal) is a substrate of the uptake transporter OCT1 and the metabolizing enzyme CYP2D6. The two genes exhibit common functional polymorphisms. Approximately 9% of Europeans and white Americans are either poor CYP2D6 metabolizers or poor OCT1 transporters. In this study, we investigated the effects of OCT1 and CYP2D6 polymorphisms on berberine pharmacokinetics in humans. We confirmed in vitro that berberine is an OCT1 substrate (KM of 7.0 μM, CLint of 306 ± 29 μL/min/mg). Common OCT1 alleles *3 to *6 showed uptake reduced by at least 65% and Oct1/2 knockout mice showed 3.2‐fold higher AUCs in liver perfusion experiments. However, in humans, poor OCT1 transporters did not show any differences in berberine pharmacokinetics compared with reference participants. In contrast, CYP2D6 polymorphisms significantly affected berberine metabolism, but exclusively in females. Females who were poor CYP2D6 metabolizers had an 80% lower M1‐to‐berberine ratio. General linear model analyses suggest strong synergistic, rather than additive, effects between female sex and CYP2D6 genotype. Overall, berberine displayed low oral bioavailability, yet females had a 2.8‐fold higher AUC and a 3.6‐fold higher Cmax than males (P < 0.001). These effects were only partially attributable to the sex‐CYP2D6 genotype interaction. In conclusion, despite berberine being an OCT1 substrate, OCT1 deficiency did not affect berberine pharmacokinetics in humans. In contrast, CYP2D6 emerges as a critical enzyme for berberine metabolism in females, but not in males, highlighting sex‐specific differences. We suggest that factors beyond CYP2D6 metabolism are determining berberine's systemic exposure, especially in males (NCT05463003)
Scalability of API-Loaded Multifilament Yarn Production by Hot-Melt Extrusion and Evaluation of Fiber-Based Dosage Forms
Get PDFFiber-based technologies are widely used in various industries, but their use in pharmaceuticals remains limited. While melt extrusion is a standard method for producing medical fibers such as sutures, it is rarely used for pharmaceutical fiber-based dosage forms. The EsoCap system is a notable exception, using a melt-extruded water-soluble filament as the drug release trigger mechanism. The challenge of producing drug-loaded fibers, particularly due to the use of spinning oils, and the processing of the fibers are addressed in this work using other approaches. The aim of this study was to develop processes for the production and processing of pharmaceutical fibers for targeted drug delivery. Fibers loaded with polyvinyl alcohol and fluorescein sodium as a model drug were successfully prepared by a continuous melt extrusion process and directly spun. These fibers exhibited uniform surface smoothness and consistent tensile strength. In addition, the fibers were further processed into tubular dosage forms using a modified knitting machine and demonstrated rapid drug release in a flow cell
Kinetic Theory of Self-Propelled Particles with Nematic Alignment
Get PDFWe present the results from kinetic theory for a system of self-propelled particles with alignment interactions of higher-order symmetry, particularly nematic ones. To this end, we use the Landau equation approach, a systematic approximation to the BBGKY hierarchy for small effective couplings. Our calculations are presented in a pedagogical way with the explicit goal of serving as a tutorial from a physicists’ perspective into applying kinetic theory ideas beyond mean-field to active matter systems with essentially no prerequisites and yield predictions without free parameters that are in quantitative agreement with direct agent-based simulation
Sustainability Science Communication: Case Study of a True Cost Campaign in Germany
Get PDFThe Anthropocene, marked by human-induced climate change, necessitates urgent action to address climate goals and respect planetary boundaries. While sustainability research provides knowledge, the first challenge lies in communicating the findings in an adequate manner to the public and several stakeholders, such as economic and political actors. Therefore, this study explores the significance of science communication in sustainability science, focusing on a case study—the True Cost Accounting (TCA) campaign by the University of Greifswald, Technical Institute of Nuremberg, and German retailer PENNY. TCA herein serves as a transparency tool, economic incentive, and discussion basis for sustainable consumption. This study investigates consumer perceptions of ecological prices of foods through a face-to-face survey during the 2023 PENNY campaign, comparing results to an informational campaign carried out in 2021. Findings indicate a high awareness of the true cost campaign in 2023, with 50.8% of participants hearing about it. Consumers’ willingness to pay true costs and potential behavior changes were explored. In comparison to results from the informational campaign of 2021, customers showed a decrease in this WTP when the true prices would actually impact their spending, indicating an attitude–behavior gap. In addition, a willingness to reduce the consumption of animal foods—if TCA was implemented—of 60.5% was determined, which suggests that TCA has the potential for sustainable behavior change. This study highlights factors that influence consumer attitudes and preferences regarding the inclusion of TCAs, such as environmental, social, and animal welfare costs. Customers’ understanding of increased prices—like, in this case, the compensation for environmental and social costs—is an argument in favor of true prices. The results emphasize the need for differentiated scientific communication strategies to bridge knowledge and action gaps in sustainability science
In-vitro-Studie zur antimikrobiellen Wirkung des blauen Lasers (445 nm)
Get PDFInfolge der fortschreitenden Entwicklung der Antibiotikaresistenzen und der sich daraus entwickelnden Suche nach alternativen antimikrobiellen Therapien hat der Laser seit Jahrzenten einen großen Stellenwert in der Patientenbehandlung. Der blaue Diodenlaser (445 nm) besitzt derzeit seine primäre Indikation in der invasiven Chirurgie. Es wird jedoch auch eine antimikrobielle Wirkung im unterschwelligen Intensitätsbereich vermutet, welche aktuell zunehmend erforscht wird.
In der hier vorliegenden Studie wurde der antimikrobielle Effekt des blauen Lasers (SIROLaser Blue, Firma Dentsply Sirona, Bensheim, Deutschland) mit einer Wellenlänge von 445 nm auf drei Mikroorganismen Candida albicans, Enterococcus faecalis und Streptococcus mutans untersucht. Dafür wurden die Mikroorganismen auf Keramikprobekörper aufgetragen und diese auf einem Positioniertisch mit dem Laser behandelt, welcher in einer Haltevorrichtung justiert wurde. Die Auswertung der Bestrahlung erfolgte in den Vorversuchen optisch über eine Vitalfärbung mittels MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromid) und in den Hauptversuchen durch die Auswertung der koloniebildenden Einheiten.
In Vorbereitung auf die Versuche wurden vorab verschiedene Trägerlösungen (PBS, H2O, K-Phosphat, Na-K-Phosphat und Tris-HCl) getestet, um eine erfolgreiche Vitalfärbung zu gewährleisten. Dabei stellten sich H2O für C. a. und E. f. und K Phosphat für S. m. am geeignetsten heraus. Außerdem wurden Vorversuche zu Positiv- und Negativkontrollen und zur Ablösung der Mikroorganismen (Wiederfindungsrate) durchgeführt. Darüber hinaus wurde der Einfluss verschiedener Laserparameter auf die Mikroorganismen getestet, um eine möglichst klinisch effektive antimikrobielle Lasereinstellung zu finden. Hierbei kristallisierte sich vor allen Dingen der Parameter Geschwindigkeit, mit der der Laser über die zu behandelnde Probe gleitet (4 mm/s, 2 mm/s, 1 mm/s), heraus. Die restlichen einstellbaren Parameter blieben in den Hauptversuchen konstant: Leistung 1 W, Abstand 1 mm, zwei Wiederholungen.
In den Hauptversuchen konnten bei allen drei Mikroorganismen statistisch signifikante Unterschiede zwischen den unbehandelten Kontrollproben (Negativkontrolle) und den behandelten Proben festgestellt werden. Die besten Ergebnisse im Sinne einer Keimreduktion wurden bei S. m. erzielt, gefolgt von E. f. und C. a.
Bei S. m. wurde eine Keimreduktion (Differenz zwischen Negativkontrolle und Behandlung) zwischen 2,0 log10 KbE/ml (4 mm/s) und 2,54 log10 KbE/ml (1 mm/s) ermittelt. Bei E. f. betrug die Keimreduktion maximal 1,78 log10 KbE/ml (1 mm/s) und bei C. a. maximal 1,02 log10 KbE/ml (1 mm/s).
Innerhalb der behandelten Gruppen konnten die mit 1 mm/s behandelten Proben verglichen mit den beiden anderen Parametern statistisch signifikante Keimreduktionen erreichen: bei S. m. und E. f. maximal 0,54 log10 KbE/ml (1 mm/s versus 4 mm/s) und bei C. a. 0,65 log10 KbE/ml (1 mm/s versus 2 mm/s). Zwischen 2 mm/s und 4 mm/s gab es bei allen drei Mikroorganismen keine statistisch signifikanten Unterschiede in den Keimreduktionen.
Gleichzeitig wurde durch die Infrarotkamera ein thermischer Einfluss auf die antimikrobielle Wirkung als vernachlässigbar klein bestätigt.
Insgesamt konnte festgestellt werden, dass die Behandlung der drei Mikroorganismen mit dem blauen Laser zu einer statistisch signifikanten Keimreduktion geführt hat. Weitere Entwicklungsarbeiten und Studien zur antimikrobiellen Wirkung sollten durchgeführt werden, um die getestete Indikationserweiterung des blauen Lasers in die Praxis überführen zu können