Oligomerisierungseigenschaften von Trialkylsilylphosphanyltrielen und Synthese neuer Phosphanidliganden

Im Rahmen der vorliegenden Arbeit werden die Eigenschaften, insbesondere die Oligomerisierung, von Organometallphosphaniden der Gruppe 13 untersucht und neue Liganden entwickelt, die einen niedrigen Oligomerisierungsgrad ermöglichen können. Die Synthese von Trialkylsilylphosphanylgallanen, –alanen und -indanen führt in Abhängigkeit der Größe der organischen Reste an den Metallen zu monomeren und dimeren Verbindungen, deren Eigenschaften durch quantenmechanische Rechnungen (DFT) untersucht wurden. Anders als allein durch sterische Effekte zur kinetischen Stabilisierung monomerer Spezies wird das freie Elektronenpaar in den neuen Phosphanid-Liganden durch Koordination einer Wolframpentacarbonyl-Einheit an das Phosphoratom abgesättigt. Damit steht es nicht mehr für eine Oligomerisierungsreaktion zur Verfügung. Eine neue, einstufige Synthese der Monowolframpentacarbonyl-Verbindung Li[W(CO)5PH2] und der Biswolframpentacarbonyl-Verbindung Li[(W(CO)5)2PH2] wurde entwickelt, wobei das Syntheseprodukt über die Wahl der Stöchiometrie gesteuert wird. Ausgehend von diesen Lithiumphosphaniden und Kalium-trialkylsilylphosphaniden konnten die Mono- und Biswolframpentacarbonyl-Liganden des Typs [W(CO)5P(H)SiR3]- und [(W(CO)5)2P(H)SiR3]- hergestellt werden. Zusammenfassend liefert die vorliegende Arbeit neue Erkenntnisse über Oligomerisierungsprozesse sowie deren Beeinflussung und Steuerbarkeit und stellt neue Liganden für die Organometallchemie zur Verfügung

Photoelektrochemische Ätz- und Oxidationstechnik für AlGaN und Anwendung in Heterostruktur-Feldeffekttransistoren

[no abstract

Barriers to and facilitators of the implementation of multi-disciplinary care pathways in primary care: a systematic review

Background: Care pathways (CPWs) are complex interventions that have the potential to reduce treatment errors and optimize patient outcomes by translating evidence into local practice. To design an optimal implementation strategy, potential barriers to and facilitators of implementation must be considered. The objective of this systematic review is to identify barriers to and facilitators of the implementation of CPWs in primary care (PC). Methods: A systematic search via Cochrane Library, CINAHL, and MEDLINE via PubMed supplemented by hand searches and citation tracing was carried out. We considered articles reporting on CPWs targeting patients at least 65 years of age in outpatient settings that were written in the English or German language and were published between 2007 and 2019. We considered (non-)randomized controlled trials, controlled before-after studies, interrupted time series studies (main project reports) as well as associated process evaluation reports of either methodology. Two independent researchers performed the study selection; the data extraction and critical appraisal were duplicated until the point of perfect agreement between the two reviewers. Due to the heterogeneity of the included studies, a narrative synthesis was performed. Results: Fourteen studies (seven main project reports and seven process evaluation reports) of the identified 8154 records in the search update were included in the synthesis. The structure and content of the interventions as well as the quality of evidence of the studies varied. The identified barriers and facilitators were classified using the Context and Implementation of Complex Interventions framework. The identified barriers were inadequate staffing, insufficient education, lack of financial compensation, low motivation and lack of time. Adequate skills and knowledge through training activities for health professionals, good multi-disciplinary communication and individual tailored interventions were identified as facilitators. Conclusions: In the implementation of CPWs in PC, a multitude of barriers and facilitators must be considered, and most of them can be modified through the careful design of intervention and implementation strategies. Furthermore, process evaluations must become a standard component of implementing CPWs to enable other projects to build upon previous experience

An Approach to Catheter Ablation of Cavotricuspid Isthmus Dependent Atrial Flutter

Much of our understanding of the mechanisms of macro re-entrant atrial tachycardia comes from study of cavotricuspid isthmus (CTI) dependent atrial flutter. In the majority of cases, the diagnosis can be made from simple analysis of the surface ECG. Endocardial mapping during tachycardia allows confirmation of the macro re-entrant circuit within the right atrium while, at the same time, permitting curative catheter ablation targeting the critical isthmus of tissue located between the tricuspid annulus and the inferior vena cava. The procedure is short, safe and by demonstration of an electrophysiological endpoint - bidirectional conduction block across the CTI - is associated with an excellent outcome following ablation. It is now fair to say that catheter ablation should be considered as a first line therapy for patients with documented CTI-dependent atrial flutter