Transition metal complexes with P,N-ligands and silylenes : synthesis and catalytic studies

We were interested to extend our library of P,N-ligands, and to investigate the influence of a five-memebered ring-chelate, since most of the previously tested ligands form six-membered ring-chelates. In consequence, twelve new phosphinomethyl-oxazolines and their corresponding iridium-complexes were prepared and tested in the enantioselective hydrogenation of unfunctionalized and functionalized olefins. The tetrasubstituted olefin 2- (4’-methoxyphenyl)-3-methyl-2-butene was reduced with higher enantioselectivity than reported for other iridium catalysts. Another objective was to examine the effect of a strong π-accepting and planar phosphorusmoiety. Three chiral phosphininoxazolines were prepared by dehydration of a water-adduct, wherein the phosphorus atom is present as a secondary phosphine oxide. The corresponding cationic iridium-complexes were synthesized. One of these complexes was also tested in the iridium-catalyzed hydrogenation and transfer-hydrogenation showing good conversion, but low to moderate enantioselectivity. We were interested in the scope of iridium-PHOX complexes in other catalytic reactions. Initial studies towards the application of this system in asymmetric catalytic Pauson-Khand reaction were completed regarding pressure influence, reproducability and the influence of the counteranion on the enantioselectivity of the reaction. 3-Phenylsubstituted enynes undergo cycloaddition with good to very good yields and good enantioselectivities. Steric hindrance at the alkene moiety leads to a strong drop in yield. Among the tested counteranions, small and weakly-coordinating anions, such as triflate, tetrafluoroborate, hexafluorophosphate and hexafluoroantimonate proved to give the highest enantioselectivities. Inspired by the recent success of NHCs in the iridium catalyzed hydrogenation, we envisioned the synthesis of iridium- and rhodium-complexes containing N-heterocyclic silylenes. Two cationic rhodium(I)-silylene complexes 187 and 188 were prepared from [Rh(cod)2]BArF 185 and 1,3-di-tert-butyl-2,3-dihydro-1H-1,3,2-diazasilol-2-ylidene 171 and its saturated analogue 172, respectively (Figure 1). Only catalytically inactive complexes were formed. The corresponding iridium-complexes were not accessible by the same method

Challenges in Modelling Social Conflicts: Grappling with Polysemy

This discussion paper originates from the preceding annual workshop of the Special Interest Group on Social Conflict and Social Simulation (SIG-SCSS) of the ESSA. The workshop especially focused on the need to identify and examine challenges to modeling social conflicts. It turned out that the polysemous nature of social conflicts makes it very difficult to get a grasp of their complexity. In order to deal with this complexity, various dimensions have to be taken into consideration, beginning with the question of how to identify a conflict in the first place. Other dimensions include the relation of conflict and rationality and how to include non-rational factors into conflict models. This involves a conception of organized action. Finally, guiding principles for model development are being discussed. We would like to invite readers of the Journal of Artificial Societies and Social Simulation to 'sow the seeds' of this debate.Social Conflicts, Conflict Models, Modelling Challenges, Polysemy, Rationality, Emotions

Die Paarbeziehung Erwachsener und Erinnerungen an die Eltern-Kind-Beziehung: eine Untersuchung zur Kontinuität von Bindung

'Von Bowlbys These ausgehend, dass die Eltern-Kind-Bindung als Modell für enge Beziehungen im weiteren Leben dient, ging es in dieser Arbeit um die Frage, inwieweit Zusammenhänge zwischen der Bindung an einen Partner im Erwachsenenalter und Erinnerungen an die Bindung an die Eltern in der Kindheit festzustellen sind. Zwei Studien wurden durchgeführt, in denen Erwachsene mit qualitativen und quantitativen Methoden zu ihrer aktuellen Bindung an einen Partner und zu ihrer früheren Bindung an die Eltern befragt wurden. Es zeigte sich, dass die Bindung an einen Partner mit zwei Dimensionen der Erinnerungen an die Eltern-Kind-Bindung zusammenhing, die Emotionale Akzeptanz seitens der Mutter in der Kindheit und die Offenheit der Befragten beim Ausdruck von Gefühlen. Emotionale Komponenten der Erinnerungen an die Eltern-Kind-Bindung erwiesen sich damit als bedeutsam für die partnerschaftliche Bindung. Keine signifikante Übereinstimmung wurde dagegen gefunden, wenn die partnerschaftliche und die kindheitsbezogene Bindung als sicher, ängstlich-ambivalent oder vermeidend klassifiziert wurden. Die Ergebnisse werden vor dem Hintergrund der These der Kontinuität von Bindung diskutiert.' (Autorenreferat)'Based on Bowlby's hypothesis that attachment to parents serves as a model for close relationships in adulthood, this study focuses on the extent to which adult attachment to a romantic partner is related to recollections of attachment to one's parents in childhood. Two studies were conducted in which adults were assessed with qualitative and quantitative methods with respect to their view of their current romantic bond and their former bond to parents. Results indicated that romantic attachment was related to two dimensions of memories of attachment to parents: feeling emotionally accepted by the mother in childhood, and the respondents' present openness in expressing feelings. Emotional components of memories of parent-child-attachment were therefore shown to be significantly related to romantic attachment. However, no significant correspondence was found when attachment to romantic partners and to parents was classified as secure, ambivalent, or avoidant. Results are discussed with respect to the continuity hypothesis of attachment.' (author's abstract)

Morphometrische Untersuchungen zur Auswirkung der Tumorlokalisation des Prostatakarzinoms auf den Wert und die Aussagekraft des PCA3-Urintests

Das Prostatakarzinom ist die häufigste Krebserkrankung des Mannes. Ergänzend zu den herkömmlichen Früherkennungsuntersuchungen mittels digital-rektaler Palpation und Messung des PSA-Wertes kann der PCA3-Score wichtige Informationen zur Entscheidung für oder gegen eine Prostatabiopsie liefern. Der PCA3-Test basiert auf der Analyse von Tumorzell-mRNA im Exprimaturin. Als Exprimaturinmarker unterliegt seine Gewinnung bestimmten physikalischen Aspekten. Neben Palpationsdruck und Loslösekraft für das Ausquetschen von Zellen als potenzielle Einflussfaktoren ist vor allem die für die Zellen zu überwindende Distanz bis zur Harnröhre zu nennen. Deshalb wurde in der vorliegenden Arbeit geprüft, ob die Höhe des PCA3-Scores von der Lokalisation der Tumoren in der Prostata in Bezug auf die Urethra und den Colliculus seminalis beeinflusst wird. Von 55 Patienten wurde das Prostatektomiepräparat nach dem Stanford-Protokoll aufgearbeitet. Für jedes einzelne Prostatektomiepräparat wurde eine exakte dreidimensionale Rekonstruktion einschließlich der Prostataoberfläche, der Tumorareale und der Harnröhre erstellt. Um die Harnröhre wurden virtuell 3 konzentrische Röhren mit einem Durchmesser von 8 mm, 16 mm und 32 mm gelegt. Um den Colliculus seminalis wurden Kugelvolumina mit 8 mm, 16 mm und 32 mm virtuell gelegt. Damit entstanden für die verschiedenen Durchmesser um die Harnröhre bzw. den Colliculus die jeweiligen Schnittvolumina zwischen dem Volumen der Tumorareale im Prostataraum und den Röhren- respektive Kugelvolumina. Diese Schnittvolumina dienen als Maßzahl für die radiale Lage der Tumorbereiche. Die Schnittvolumina wurden dann mit dem jeweiligen PCA3 Wert in Bezug gesetzt. Zudem wurden die folgenden klinischen und histopathologischen Parameter erhoben: Alter, PSA-Wert, PCA3-Score, Gleason-Score, Tumoranzahl, TNM-Stadium, Prostata- und Tumorvolumen, sowie Tumordichte. Es zeigte sich weder für die Lagebeziehung der Tumoren zur Harnröhre noch zum Colliculus seminalis ein signifikanter Zusammenhang zur Höhe des PCA3-Scores. Die klinischen und histopathologischen Parameter zeigten ebenfalls keine Korrelation zur Höhe des PCA3-Scores. Es konnte damit gezeigt werden, dass die Tumorlage in der Prostata keine Auswirkung auf die Höhe des PCA3-Scores hat. Die Tumorlage stellt keine Limitation in der Aussagekraft des PCA3-Scores dar. Damit konnte die Lage eines Prostatakarzinoms als ein als potenziell möglich erscheinender Einflussfaktor für die artifizielle Modulation des PCA3-Scores ausgeschlossen werden

Challenges in modelling social conflicts: grappling with polysemy

International audienceThis discussion paper originates from the preceding annual workshop of the Special Interest Group on Social Conflict and Social Simulation (SIG-SCSS) of the ESSA. The workshop especially focused on the need to identify and examine challenges to modeling social conflicts. It turned out that the polysemous nature of social conflicts makes it very difficult to get a grasp of their complexity. In order to deal with this complexity, various dimensions have to be taken into consideration, beginning with the question of how to identify a conflict in the first place. Other dimensions include the relation of conflict and rationality and how to include non-rational factors into conflict models. This involves a conception of organized action. Finally, guiding principles for model development are being discussed. We would like to invite readers of the Journal of Artificial Societies and Social Simulation to 'sow the seeds' of this debate

What’s mathematics doing here? The role of mathematics in German Physics Olympiad tasks

Physics competitions target at motivating students for engaging in physics and at promoting students talented in physics. Physics competitions also aim at conveying a picture of physics as a scientific discipline, going beyond regular physics classes in school, and should thus also include a more intense mathematization of physics problems. Given that physics students often struggle with mathematics, mathematics in the competition may pose a challenge beyond the intended physics challenge. The present paper therefore presents an analysis of theoretical tasks employed in the German Physics Olympiad. Mathematical requirements were (1) identified by analyzing sample solutions and (2) compared to mathematics curricula. Then, (3) the solutions were categorized regarding whether the mathematics employed was used in a tool-like manner, a structuring manner, or both. Findings indicate that the first competition round typically includes rather basic mathematical requirements which are addressed in lower secondary mathematics education. In the higher rounds, more advanced mathematics is needed, which is only taught in the last years of high school, or not taught at all. The structural role of mathematics proved to be essential in the analyzed tasks. Beside the (intended) physics challenges, participants thus have to deal with mathematics they have not learned at school and have to apply mathematics in a different way than is often done at school when participating in the competition. As a consequence, unintended negative effects may occur, potentially counteracting the aim to promote students talented in physics. Implications for science education and future research are discussed

Introduction of an Assistance System to Support Domain Experts in Programming Low-code to Leverage Industry 5.0

The rapid technological leaps of Industry 4.0 increase the pressure and demands on humans working in automation, which is one of the main motivators of Industry 5.0. In particular, automation software development for mechatronic systems becomes increasingly challenging, as both domain knowledge and programming skills are required for high-quality, maintainable software. Especially for small companies from automation and robotics without dedicated software engineering departments, domain-specific low-code platforms become indispensable that enable domain experts to develop code intuitively using visual programming languages, e.g., for tasks such as retrofitting mobile machines. However, for extensive functionalities, visual programs may become overwhelming due to the scaling-up problem. In addition, the ever-shortening time-to-market increases the time pressure on programmers. Thus, an assistance system concept is introduced that can be implemented by low-code platform suppliers based on combining data mining and static code analysis. Domain experts are supported in developing low-code by targeted recommendations, metric-based complexity measurement, and reducing complexity by encapsulating functionalities. The concept is implemented for the industrial low-code platform HAWE eDesign to program hydraulic components in mobile machines, and its benefits are confirmed in a user study and an industrial expert workshop.Comment: 8 pages, https://ieeexplore.ieee.org/abstract/document/983945