A Simple Nickel Catalyst Enabling an E‐Selective Alkyne Semihydrogenation

Stereoselective alkyne semihydrogenations are attractive approaches to alkenes, which are key building blocks for synthesis. With regards to the most atom economic reducing agent dihydrogen (H 2 ), only few catalysts for the challenging E ‐selective alkyne semihydrogenation have been disclosed, each with a unique substrate scope profile. Here, we show that a commercially available nickel catalyst facilitates the E ‐selective alkyne semihydrogenation of a wide variety of substituted internal alkynes. This results in a simple and broadly applicable overall protocol to stereoselectively access E ‐alkenes employing H 2 which could serve as a general method for synthesis.DFG, 352364740, Diwasserstoff-vermittelte nachhaltige BindungsknüpfungsreaktionenTU Berlin, Open-Access-Mittel - 201

Stereoselective alkyne semihydrogenations with an air-stable copper(I) catalyst

An air-stable and preactivated copper(I) hydroxide/N-heteroyclic carbene (NHC) complex for alkyne semihydrogenations is reported. Next to an enhanced practicability of the process, the resulting alkenes are obtained with high Z-selectivities and no overreduction to the corresponding alkanes

The Digital Constellation

The emergence of the digital society has become one of the most pressing research topics in social science. So far, political science has been at the margins of the debate because it has been restricted by a rather narrow focus on networked communications. The paper attempts to change this by presenting a more encompassing way to address digitalisation from within political science. After briefly criticising the development of the research in political science the paper reconstructs at length some of the most popular conceptualisations in neighbouring disciplines. While we highlight the commonalities and strengths of those approaches in theorising digitalisation, we criticise their rather derivative understanding of democratic practices and the political as such. We go on to propose a modified understanding - which we term the "digital constellation" - that looks at the changing shape of democracy by developing a much more nuanced understanding of the interplay between societies and technologies. Finally, we illustrate the argument in an exemplary analysis of the changes occurring in political representation in the context of digitalisation

Catalytic Hydrogenations with Cationic Heteroleptic Copper(I)/N-Heterocyclic Carbene Complexes

A new heteroleptic cationic copper(I) complex bearing two N-heterocyclic carbene (NHC) ligands has been prepared. In situ, a Cu-O bond can be generated which enables the complex to catalytically activate H (2) . The resulting complex shows activity in catalytic chemo- and stereoselective alkyne semihydrogenations as well as conjugate reductions of enones

Die digitale Konstellation: eine Positionsbestimmung

Die Entwicklung der digitalen Gesellschaft ist in den Sozialwissenschaften zu einem zentralen Forschungsgegenstand aufgestiegen; in der Politikwissenschaft gilt allerdings, dass die Auseinandersetzung auf eher wenige Schwerpunkte - insbesondere Digitalisierung als vernetzte Kommunikation - beschränkt geblieben ist. Der Beitrag macht einen Vorschlag für eine andere Form der politikwissenschaftlichen Auseinandersetzung indem er - nach einer kritischen Rekonstruktion der Forschungsentwicklung in der Politikwissenschaft - breit rezipierte Diagnosen der digitalen Gesellschaft in Nachbardisziplinen wie der Soziologie und Rechtswissenschaft (Baecker, Nassehi, Reckwitz, Stalder und Vesting) rekonstruiert. Er arbeitet übergreifende Erkenntnisse im Digitalisierungsverständnis dieser Ansätze heraus, kritisiert jedoch deren Konzeptualisierung von Politik und Demokratie. Auf dieser Grundlage wird sodann ein Vorschlag unterbreitet, eine in der Politikwissenschaft anschlussfähigere Perspektive mittels des Konzepts der "digitalen Konstellation" zu entwickeln. Dieses untersucht das Wechselspiel technischer und gesellschaftlicher Entwicklungen in Bezug auf den Zusammenhang zum Formwandel von Demokratie. Abschließend wird dies in einer exemplarischen Analyse von Veränderungen des Repräsentationskonzepts im digitalen Kontext veranschaulicht.The emergence of the digital society has become one of the most pressing research topics in social science. So far political science has been at the margins of the debate being restricted by a rather narrow focus on networked communications. The paper attempts to change this by presenting a more encompassing way to thematize digitalization from within political science. After briefly having criticized the research development in political science the paper reconstructs at length some of the most popular conceptualizations in neighboring disciplines. While we highlight the commonalities and strengths of those approaches in theorizing digitalization, we criticize their rather derivative understanding of democratic practices and the political as such.We go on to propose a modified understanding - labeled the "digital constellation" - that looks at the changing shape of democracy by developing a much more nuanced understanding of the interplay of societies and technology. Finally, the argument is illustrated by a short exemplary analysis of the changes occurring in political representation in the context of digitalization

Influence of utilizing hemodialysis membranes outside-in on solute clearance and filtration efficiency – One step towards a novel combined lung and kidney support device

Many membrane oxygenator patients suffer from renal disfunction. For these patients, a novel device integrating artificial lung and kidney support is being developed. Although outside-in blood flow is standard for membrane oxygenators, this is not typical for hemodialysis systems. The effect of outside-in blood flow on the efficiency of hemodialysis fibers for continuous hemodialysis and hemofiltration is yet unclear. This study evaluates the efficiency of commercial hemodialyzer membranes utilized outside-in compared to traditional inside-out mode regarding clearance of urea and creatinine, and ultrafiltration coefficient during in-vitro tests with porcine blood. Our results showed that dialyzers (1.2 m2, asymmetric hollow fibers) utilized outside-in had similar clearances of urea and creatinine compared to dialyzers used in the traditional mode (p &gt; 0.7). However, outside-in dialyzers had an ultrafiltration coefficient four times lower than dialyzers applied in a conventional way, but adequate fluid removal could be achieved by controlling pressures in the system. This in-vitro study indicates that outside-in fibers could be sufficiently effective to maintain typical continuous renal replacement therapy doses. We regard this as one step towards a novel device with a mixed membrane fiber bundle utilizing blood flow outside both hemodialysis fibers and gas exchange fibers to provide simultaneous lung and kidney support.</p

The Impacts Of Neighbourhood Traffic Management

A major traffic-related problem faced by residents is speeding, which not only causes safety concerns, but also noise issues. Traffic calming is a much favoured traffic management tool employed by road controlling authorities to primarily reduce vehicle speed, hence improve community liveability. This research aimed to investigate the impacts of traffic calming on speed, safety and traffic noise. The objectives included developing models for the prediction of speed and noise on traffic-calmed streets, and providing guidance for good design practices. Speeds of individual vehicles as they approached and crossed traffic calming devices were observed in order to identify the behaviour of individual drivers. Results indicated that the speed hump and the raised angled slow point produced the largest speed reductions and least variation in speeds, while mid-block narrowings had no significant speed changes. Inter-device speed was found to be mainly controlled by the separation between devices. 85th percentile speeds at distances from calming devices were 40 – 45 km/h for vertical deflections and 45 – 55 km/h for horizontal deflections. Speeds on approach to speed humps were found to be influenced by the distance available on the approaches, while operating speed at the speed humps were partly influenced by the hump width relative to the road width. There was evidence of safety benefits of traffic calming overall, despite mid-block crashes increasing post-calming. However, there was no association between the traffic calming and the crashes, which appeared to probably be due to other factors, human factors in particular. Noise levels produced by light vehicles across speed humps were in fact lower than on a flat section of road, given their respective mean speeds. At a reference speed of 25 km/h, noise levels produced over the 100 mm hump were 3.6 dBA higher than those produced by the 75 mm hump