Investigating people’s preferences for car-free city centers: A discrete choice experiment

In the face of climate change and growing health hazards due to air pollution in urban centers, private car use is being increasingly criticized. At the same time, research suggests that there is an unsatisfied demand for modes of transportation other than private cars. In fact, many cities all over Europe have already established car-restricted or car-free areas. This paper uses a discrete choice experiment to learn more about people’s preferences regarding a car-free city center in Berlin, Germany. We find that, given the current infrastructure, around 60% of our respondents are willing to accept a car-free city center. By improving infrastructure for cyclists, willingness to accept a car-free city center strongly increases. Similarly, improving the network of bus stops and train stations as well as rededicating released streets to recreational uses would contribute to a higher acceptance of a car-free city center. Using a random parameters logit model, we have also identified observed and unobserved sources of heterogeneity

Computed tomography-3D-volumetry: a valuable adjunctive diagnostic tool after bariatric surgery

Aim: After bariatric surgery, a variety of complaints may arise. Identification of the causes of such symptoms is often challenging due to the postoperatively modified anatomy. While standard examinations with upper endoscopy and upper gastrointestinal series might miss the three-dimensional anatomic nature of the problem, quantitative three-dimensional computed tomography volumetry (3D-CT) of the upper gastrointestinal tract offers a novel, adjunctive examination, revealing the detailed anatomy. The aim of this study was to analyse the clinical value of 3D-CT in post-bariatric patients.Methods: Prospective data of 279 patients, who underwent 3D-CT due to complications after different bariatric procedures, were retrospectively analysed. Directly before examination, the surgical-modified stomach was distended with an effervescent-powder. CT images were 3D-reconstructed and, further, gastric volume was calculated.Results: In total, 279 patients were examined. Time between surgery and examination was significantly different between Roux-en-Y gastric bypass (n = 168) (54.3 ± 38.6 months) and sleeve gastrectomy (n = 78) (27.8 ± 21.7 months) (P = 0.0001). Others, less numerous, but included procedures were one-anastomosis/mini gastric bypass (n = 11), and dated procedures, such as the vertical banded gastrostomy. The examination allowed calculation of the gastric volume, and the 3D-reconstructions depicted accurately the pivotable anatomic details of the modified upper gastrointestinal tract with 360° view. As a robust result, patients with a higher gastric volume showed more weight regain after sleeve gastrectomy.Conclusion: 3D-CT is easy-to-perform and facilitates identification of the post-surgical three-dimensional gastric anatomy. It represents a valuable additional diagnostic tool in post-bariatric patients with post-procedural complications. 3D-CT might be an important preoperative tool prior to revisional surgery. In addition, this is the only exact and reproducible calculation of the gastric volume

Transition Metal-Catalysed Intermolecular Reaction of Allenes With Oxygen Nucleophiles: A Perspective

Transition metal catalysed hydroalkoxylation of allenes has received much attention in recent years, and both the intra- and intermolecular versions have been reported. Gold(I) complexes are among the most active catalysts for these processes. This critical perspective article will cover the progress in this field, analysing the intermolecular metal-catalysed reaction of allenes using palladium, iridium, rhodium, ruthenium, gold and platinum, in the presence of alcohols, water or carboxylic acids, and the mechanistic implications of these processes depending on the metal used

Enantioselective Redox-Neutral Rh-Catalyzed Coupling of Terminal Alkynes with Carboxylic Acids Toward Branched Allylic Esters

We report on the first enantioselective variant of the atom-economic and redox-neutral coupling of carboxylic acids with terminal alkynes under rhodium catalysis utilizing the chiral, bidentate (<i>R</i>,<i>R</i>)-Cp-DIOP ligand. This represents the first example of this convenient asymmetric access to valuable branched allylic esters. The utility of this methodology is demonstrated by both a reaction performed on large scale and a short three-step synthesis of two naturally occurring γ-butyrolactones. A stereochemical model explaining the observed absolute configuration of the products based on DFT calculations is given

Enantioselective Synthesis of Branched Allylic Esters via Rhodium-Catalyzed Coupling of Allenes with Carboxylic Acids

We report on the first intermolecular asymmetric catalytic regio- and enantioselective addition of carboxylic acids to terminal allenes to form valuable branched allylic esters, employing a rhodium­(I)/(<i>R,R</i>)-DIOP catalyst system