Complexes with Dative Bonds between d‐ and s‐Block Metals: Synthesis and Structure of [(Cy3P)2Pt?Be(Cl)X] (X=Cl,Me)

A platinum–beryllium adduct (see structure) was prepared by the reaction of [Pt(PCy₃)₂] and BeCl₂. Treatment with methyllithium resulted in ligand substitution at the beryllium center. Both complexes were structurally characterized and display unprecedented two‐center two‐electron bonds between a transition metal and beryllium.

     

On the computation of <Emphasis Type="Italic">C</Emphasis>* certificates

The cone of completely positive matrices C* is the convex hull of all symmetric rank-1-matrices xx ^T with nonnegative entries. While there exist simple certificates proving that a given matrix \({B\in C^*}\) is completely positive it is a rather difficult problem to find such a certificate. We examine a simple algorithm which—for a given input B—either determines a certificate proving that \({B\in C^*}\) or converges to a matrix \({\bar S}\) in C* which in some sense is “close” to B. Numerical experiments on matrices B of dimension up to 200 conclude the presentation.     

A large class of solutions for the instationary Navier–Stokes system

We investigate very weak solutions to the instationary Navier–Stokes system being contained in where is a bounded domain and . The chosen space of data is small enough to guarantee uniqueness of solutions and existence in case of small data or short time intervals. On the other hand, the data space is large enough that every vector field in is a very weak solution for appropriate data. The solutions and the data depend continuously on each other.      

Massively Parallel Particle Simulations on Graphics Processing Units with CUDA

Particle methods are a powerful tool to model dynamic systems. Thereby, the system is discretized by a large number of particles, which are interacting via local, predefined particle-particle interaction laws. The resulting computational effort includes neighborhood search, computation of interaction forces and state update via time integration. Particle methods are used in a lot of different fields of applications like computer science, physics and engineering sciences. As the analyzed systems' number of particles constantly grow, performance enhancement has become an important part of present algorithm development. Besides the well-established approach of algorithm parallelization on multi-core CPUs or CPU clusters, modern graphics processing units (GPUs) present a different and trend-setting possibility for massive parallelization even on desktop computers. Among the top four supercomputers of the world, three are already using NVIDIA GPUs. In late 2006, NVIDIA introduced the first GPUs optimized for general purpose calculations. This was followed by the introduction of a new computing architecture differing from the standard graphics user-interface like OpenGL. This architecture is called Compute Unified Device Architecture (CUDA). It enables the user to program the GPU using standard C commands with few additional runtime functions. The differences in architecture between CPU and GPU result in a completely different algorithm implementation. So, a performance evaluation of different types of particle systems implemented on a GPU using CUDA and on a standard CPU is presented. (© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Highly efficient atom transfer radical addition reactions with a RuIII complex as a catalyst precursor

The combination of the air-stable RuIII complex [Cp*RuCl2(PPh3)] with AIBN can be used to catalyze the atom transfer radical addition reactions of polychlorinated compounds and of sulfonyl chlorides to olefins with unprecedented turnover numbers of up to 44 000.     

Separation and quantification of inulin in selected artichoke (Cynara scolymus L.) cultivars and dandelion (Taraxacum officinale WEB. ex WIGG.) roots by high-performance anion exchange chromatography with pulsed amperometric detection

The profile of fructooligosaccharides and fructopolysaccharides in artichoke heads and dandelion roots was investigated. For this purpose, a suitable method for high-performance anion exchange chromatography with pulsed amperometic detection was developed. The separation of monomers, oligomers and polymers up to a chain length of 79 sugar residues was achieved in one single run. Glucose, fructose, sucrose and individual fructooligosaccharides (kestose, nystose, fructofuranosylnystose) were quantified in six different artichoke cultivars and in dandelion roots. The contents ranged from 12.9 g/kg DM to 71.7 g/kg DM for glucose, from 15.8 g/kg DM to 67.2 g/kg DM for fructose, and from 16.8 g/kg DM to 55.2 g/kg DM for sucrose in the artichoke heads. Kestose was the predominant fructooligosaccharide, followed by nystose and fructofuranosylnystose. In four cultivars fructofuranosylnystose was only detectable in traces and reached its maximum value of 3.6 g/kg DM in the cultivar Le Castel. Furthermore, an average degree of polymerization of 5.3 to 16.7 was calculated for the individual artichoke cultivars, which is noticeably lower than hitherto reported. In contrast, the contents of kestose, nystose and fructofuranosylnystose in dandelion root exceeded that of artichoke, reflecting the short chain characteristic of the inulin, which was confirmed by chromatographic analysis.     

Visualization of Protein‐Specific Glycosylation inside Living Cells

Protein glycosylation is a ubiquitous post‐translational modification that is involved in the regulation of many aspects of protein function. In order to uncover the biological roles of this modification, imaging the glycosylation state of specific proteins within living cells would be of fundamental importance. To date, however, this has not been achieved. Herein, we demonstrate protein‐specific detection of the glycosylation of the intracellular proteins OGT, Foxo1, p53, and Akt1 in living cells. Our generally applicable approach relies on Diels–Alder chemistry to fluorescently label intracellular carbohydrates through metabolic engineering. The target proteins are tagged with enhanced green fluorescent protein (EGFP). Förster resonance energy transfer (FRET) between the EGFP and the glycan‐anchored fluorophore is detected with high contrast even in presence of a large excess of acceptor fluorophores by fluorescence lifetime imaging microscopy (FLIM).     

Raffinose + Raffinase = Raffinade: Raffiniert!

Raffinose has been obtained by extraction with 50% ethanol from the seeds of the Sweet Blue Lupine and purified first via a Cation exchange column and finally by analytical HPLC using a RI‐detector. All analytical spectra were recorded and are reproduced either in the main part or in the supporting information. The NMR‐ and mass‐spectra have been interpreted and compared with theoretical calculations of the ¹³C chemical shifts. The project is a follow up of the recent book “Classics in Spectroscopy” by S. Berger und D. Sicker (Wiley‐VCH 2009).     

Miniaturized highly brilliant diode laser modules for future display applications

We demonstrate diode laser modules with high spectral radiance larger than 1 GW/cm²/sr/nm in the visible spectral range. These highly brilliant laser light sources enable the development of next-generation 3D displays. About 1W output power from small-sized modules was achieved at 635 nm by direct diode laser emission and at 530 nm using single pass second harmonic generation (SHG) of a highly brilliant near-infrared laser diode.