Universal transition state scaling relations for (de)hydrogenation over transition metals.

We analyse the transition state energies for 249 hydrogenation/dehydrogenation reactions of atoms and simple molecules over close-packed and stepped surfaces and nanoparticles of transition metals using Density Functional Theory. Linear energy scaling relations are observed for the transition state structures leading to transition state scaling relations for all the investigated reactions. With a suitable choice of reference systems the transition state scaling relations form a universality class that can be approximated with one single linear relation describing the entire range of reactions over all types of surfaces and nanoclusters.

Electronic structure calculations with GPAW: a real-space implementation of the projector augmented-wave method.

Electronic structure calculations have become an indispensable tool in many areas of materials science and quantum chemistry. Even though the Kohn-Sham formulation of the density-functional theory (DFT) simplifies the many-body problem significantly, one is still confronted with several numerical challenges. In this article we present the projector augmented-wave (PAW) method as implemented in the GPAW program package (https://wiki.fysik.dtu.dk/gpaw) using a uniform real-space grid representation of the electronic wavefunctions. Compared to more traditional plane wave or localized basis set approaches, real-space grids offer several advantages, most notably good computational scalability and systematic convergence properties. However, as a unique feature GPAW also facilitates a localized atomic-orbital basis set in addition to the grid. The efficient atomic basis set is complementary to the more accurate grid, and the possibility to seamlessly switch between the two representations provides great flexibility. While DFT allows one to study ground state properties, time-dependent density-functional theory (TDDFT) provides access to the excited states. We have implemented the two common formulations of TDDFT, namely the linear-response and the time propagation schemes. Electron transport calculations under finite-bias conditions can be performed with GPAW using non-equilibrium Green functions and the localized basis set. In addition to the basic features of the real-space PAW method, we also describe the implementation of selected exchange-correlation functionals, parallelization schemes, ΔSCF-method, x-ray absorption spectra, and maximally localized Wannier orbitals.

Anisotropic multiband many-body interactions in LuNi2B2C.

We present a comprehensive de Haas-van Alphen study on the nonmagnetic borocarbide superconductor LuNi2B2C. The analysis of the angular-dependent effective masses for different bands in combination with full-potential density functional calculations allowed us to determine the mass-enhancement factors, lambda, for the different electronic bands and their wave-vector dependences. Our data clearly show the anisotropic multiband character of the superconductivity in LuNi2B2C.

[Combined endoscopic and percutaneous transhepatic approach in postsurgical common bile duct occlusion]. / Kombiniertes endoskopisches und transhepatisch-perkutanes Vorgehen bei postoperativer kompletter Gallengangsokklusion.

UNLABELLED: Combined endoscopic and percutaneous transhepatic approach in postsurgical common bile duct occlusion. HISTORY AND CLINICAL FINDINGS: A 48-year-old patient was transferred to our hospital suffering from acute cholangitis due to complete bile duct occlusion one year after a laparoscopic cholecystectomy. Main complaints were fever over 40;C and chills, accompanied by right upper quadrant abdominal pain and jaundice. INVESTIGATIONS: Cholestastic enzymes, transaminases and leucocytes were increased. Transabdominal utrasound showed massive dilatation of the intrahepatic bile ducts. ERCP was performed and revealed a complete and impassable obstruction of the proximal common bile duct. TREATMENT AND COURSE: The bile duct occlusion following cholecystectomy was the reason for the patient inverted question marks cholangitis. Neither via ERCP nor via the percutaneous transhepatic approach was it possible to make a communication between the proximal and the distal biliary system, none of the guidewires being able to pass the obstruction. However, we finally managed to pass the obstruction in a combined endoscopic-percutaneous transhepatic rendezvous technique. The patient received a percutaneous large-calibre plastic prosthesis (Yamakawa type). 4 months after the procedure the stenosis could hardly be detected. CONCLUSION: Endoscopic treatment is successful in most patients with post-cholecystectomy bile duct strictures. Therefore, repeated surgery is usually not necessary. Even in complete bile duct occlusions, the combined endoscopic-percutaneous transhepatic method can re-open the obstruction and is therefore a possible alternative to surgery in selected cases.

[Billroth II. Surgery of the stomach]. / Nach Billroth II operierter Magen

In different intervals 220 patients were examined after a resection of the stomach with Billroth's second operation. 179 of them spoke about complaints of different degrees of severity. The cases in question were an early dumping syndrome in 83 patients, which, with the exception of 7 patients, could be removed by simple dietetic measures, such as the elimination of incompatible foodstuff. Again and again the symptoms could be evoked by provocation with it. The method described by Henley proved as correcting operation. Apart from a few exception the fitness for work was not restricted by Billroth's second operation. In shift work or severe physical work a change of the working place was striven for. The body-weight which was reduced already before the operation again increased after operation in 50%, but reached the normal only in 20%. Recidivation ulcera and anastomositis of a suture were rare findings. Stump gastritis is no own clinical picture. Also in this case in histologically still normal mucous membrane earlier histochemical changes develop in the sense of a chronic gastritis with a reduction of the adenosin triphosphatase, the acid tissue phosphatase and succinodehydrogenase.