Strahlflächen als Verallgemeinerungen der Cesàro-Kurven

Ohne Zusammenfassung     

Emil Müllers Leben und Wirken

Ohne ZusammenfassungVortrag, gehalten in der Mathematischen Gesellschaft in Wien am 27. Jänner 1928.     

A top down approach to protein structural studies using chemical cross-linking and Fourier transform mass spectrometry

Mass spectrometric analysis of wild-type proteins that have been covalently modified by bifunctional cross-linking reagents and then digested proteolytically can be used to obtain low-resolution distance constraints, which can be useful for protein structure determination. Limitations of this approach include time-consuming separation steps, such as the separation of internally cross-linked protein monomers from covalent dimers, and a susceptibility to artifacts due to low levels of natural and man-made peptide modifications that can be mistaken for cross-linked species. The results presented here show that when a crude cross-linked protein mixture is injected into an electrospray ionization Fourier transform mass spectrometry (ESI-FTMS) instrument, the cross-link positions can be localized by fragmentation and mass spectrometry on the 'gas-phase purified' singly internally cross-linked monomer. Our results show that reaction of ubiquitin with the homobifunctional lysine-lysine cross-linking reagent dissuccinimidyl suberate (DSS) resulted in two cross-links consistent with the known ubiquitin tertiary structure (K6-K11 and K48-K63). Because no protein or peptide chemistry steps are needed, other than the initial cross-linking, this new top down approach appears well suited for high-throughput experiments with multiple cross-linkers and reaction conditions. Published in 2002 by John Wiley & Sons, Ltd.     

Reactions of pentafluorophenylxenon(II) hexafluoroarsenate [C6F5Ze] [AsF6] with halide anions in acetonitrile

Reactions of [C₆F₅Xe]⁺ [AsF₆]⁻ in acetonitrile with halide anions X⁻ show different results depending on X. If X = I, Br or Cl, then C₆F₅X is obtained. If X = F, then C₆F₅H and C₆F₅---C₆F₅ are produced, and if X = HF₂, then C₆F₆, C₆F₅H and C₆F₅---C₆F₅ are formed.     

Charged exciton resonances in two and three dimensions

Resonances of three-body Coulomb systems are investigated in two and three dimensions. The complex scaling method combined with the stochastic variational approach has been used to calculate the position (energy and width) of the resonance states. The dependence of the resonance states on the mass ratio of the constituents and the dimensionality of the space is studied. It is found that the width of the resonance states behaves very differently in 2D and 3D for molecule-like cation systems. The calculated lifetimes of the resonances are in the nano- and picosecond region, and these states might be experimentally observable in excitonic trions in semiconductor quantum dots. Correspondence: K. Varga, Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37235, USA     

Rapid roughening in thin film growth of an organic semiconductor (diindenoperylene)

The scaling exponents alpha, beta, and 1/z in thin films of the organic molecule diindenoperylene deposited on SiO2 under UHV conditions are determined. Atomic-force microscopy, x-ray reflectivity, and diffuse x-ray scattering were employed. The surface width displays power law scaling over more than 2 orders of magnitude in film thickness. We obtained alpha = 0.684+/-0.06, beta = 0.748+/-0.05, and 1/zeta = 0.92+/-0.20. The derived exponents point to an unusually rapid growth of vertical roughness and lateral correlations. We suggest that they could be related to lateral inhomogeneities arising from the formation of grain boundaries between tilt domains in the early stages of growth.     

Pr?parative Trennung von biologisch aktiven Ribonucleins?uren durch HPLC

Ohne Zusammenfassung

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Preparative separation of biologically active ribonucleic acids by HPLC