Chelate von Chinolin-8-ol-Derivaten. XII. Die Kristall- und Molekülstruktur von Bis(7-isopropylchinolin-8-olato)nickel(II)

Chelates of 8-Quinolinol Derivatives. XII. Crystal and Molecular Structure of Bis(7-isopropyl-8-quinolinato)nickel(II) The crystal and molecular structure of bis(7-isopropyl-8-quinolinato)nickel(II) was determined by X-ray diffraction. The structure is monoclinic with the space group P2₁/n (Z = 2, 1403 observed independent reflections, R = 0.049. Lattice dimensions at 20°C: a = 1328.3(5) pm, b = 632.8(2) pm, c = 1330.0(5) pm, β = 112.99(3)°). The coordination of the nickel atom is planar with the quinoline rings in trans position.     

Ion chromatographic determination of platinum in biotic materials

A method for the determination of platinum is presented. The procedure consists of a high-pressure digestion of the sample followed by an ion Chromatographic separation. Then the platinum chloro complex is detected by UV-absorption.     

Intra- and intergroup vocal behavior in resident killer whales, Orcinus orca

Vocal communication within and between groups of individuals has been described extensively in birds and terrestrial mammals, however, little is known about how cetaceans utilize their sounds in their natural environment. Resident killer whales, Orcinus orca, live in highly stable matrilines and exhibit group-specific vocal dialects. Single call types cannot exclusively be associated with particular behaviors and calls are thought to function in group identification and intragroup communication. In the present study call usage of three closely related matrilines of the Northern resident community was compared in various intra- and intergroup contexts. In two out of the three matrilines significant changes in vocal behavior depending both on the presence and identity of accompanying whales were found. Most evidently, family-specific call subtypes, as well as aberrant and variable calls, were emitted at higher rates, whereas "low arousal" call types were used less in the presence of matrilines from different pods, subclans, or clans. Ways in which the observed changes may function both in intra- and intergroup communication.     

Beam-helicity asymmetry in photon and pion electroproduction in the Δ(1232)-resonance region at Q2 = 0.35(GeV/c)2

The beam-helicity asymmetry has been measured simultaneously for the reactions p→epγ and p→epπ ⁰ in the Δ(1232)-resonance region at Q ² = 0.35(GeV/c)². The experiment was performed at MAMI with a longitudinally polarized beam and an out-of-plane detection of the proton. The results are compared with calculations based on dispersion relations for virtual Compton scattering and with the MAID model for pion electroproduction. There is an overall good agreement between experiment and theoretical calculations. The remaining discrepancies may be ascribed to an imperfect parametrization of some γ ^(*) N→πN multipoles, mainly contributing to the non-resonant background. The beam-helicity asymmetry in both channels (γ and π ⁰) shows a good sensitivity to these multipoles and should allow future improvement in their parametrization.     

Local fracture resistance based on microstructural efficiency concept and simulation of injection molding

Local fracture resistance (FR) of short (SGF) and discontinuous long glass fibre (LGF) reinforced polypropylene (PP) was predicted using the ‘microstructural efficiency concept’ together with a simulation program for fibre orientation in injection molding. The ‘microstructural efficiency concept’ describes the relation between microstructural parameters such as the fibre content, the fibre aspect ratio and the processing (injection molding) induced layer structure taking also into account the local fibre orientation. The local fibre orientation in injection molding was predicted with the MOLDFLOW^®-software. The predicted local FR was compared with the measured one, which was determined by using compact tension samples and linear elastic fracture mechanics (LEFM). The comparison showed, that for SGF-PP good consistence between the predicted and measured FR existed, for LGF-PP the discrepancy was higher. Yet for both materials, the ‘microstructural efficiency concept’ together with the results obtained from the simulation of the fibre orientation can be used for FR prediction of an injection molded workpiece.     

The Cauchy Relations in Linear Elasticity Theory

In linear elasticity, we decompose the elasticity tensor into two irreducible pieces with 15 and 6 independent components, respectively. The vanishing of the piece with 6 independent components corresponds to the Cauchy relations. Thus, for the first time, we recognize the group-theoretical underpinning of the Cauchy relations.     

Interaction of isotropic turbulence with a normal shock wave

The evolution of incompressible and compressible isotropic 2-d turbulent fields interacting with a normal shock wave up to Mach numbers of 2.4 was investigated by means of direct numerical simulation using an ENO scheme. A comparison of statistics with linear analysis results is presented. Vorticity amplification in the DNS agrees well with the linear theory. Energy spectra are enhanced more in the small scales than in the large scales for incoming incompressible turbulence. The amplification rate for initially compressible turbulence is comparatively small.     

Ultraviolet Absorption Induces Hydrogen‐Atom Transfer in G⋅C Watson–Crick DNA Base Pairs in Solution

Ultrafast deactivation pathways bestow photostability on nucleobases and hence preserve the structural integrity of DNA following absorption of ultraviolet (UV) radiation. One controversial recovery mechanism proposed to account for this photostability involves electron‐driven proton transfer (EDPT) in Watson–Crick base pairs. The first direct observation is reported of the EDPT process after UV excitation of individual guanine–cytosine (G?C) Watson–Crick base pairs by ultrafast time‐resolved UV/visible and mid‐infrared spectroscopy. The formation of an intermediate biradical species (G[?H]?C[+H]) with a lifetime of 2.9 ps was tracked. The majority of these biradicals return to the original G?C Watson–Crick pairs, but up to 10 % of the initially excited molecules instead form a stable photoproduct G*?C* that has undergone double hydrogen‐atom transfer. The observation of these sequential EDPT mechanisms across intermolecular hydrogen bonds confirms an important and long debated pathway for the deactivation of photoexcited base pairs, with possible implications for the UV photochemistry of DNA.