Weak convergence of infinite-dimensional diffusions 1

Continuous dependence - in the sense of weak convergence of laws - of martingale solutions to stochastic partial differential equations on coefficients is studied, the results obtained being applicable to equations with rapidly oscillating coefficients. In the proofs, Gatarek's and Goldys’ recent approach to martingale solutions is substantially used     

Exponential Integrability of Stochastic Convolutions

Sufficient conditions are found for stochastic convolution integralsdriven by a Wiener process in a Hilbert space to belong to theOrlicz space exp L²; standard exponential tail estimates followfrom these results. Proofs are based on the extrapolation theoryand are rather simple.     

Vibrational excitation energies from vibrational coupled cluster response theory

Response theory in the context of vibrational coupled cluster (VCC) theory is introduced and used to obtain vibrational excitation energies. The relation to the vibrational configuration interaction (VCI) approach is described, and the increase in accuracy of VCC response energies relative to VCI energies is discussed theoretically in terms of a perturbational order expansion and demonstrated numerically. To illustrate the theory, a pilot implementation is used to obtain anharmonic vibrational frequencies for fundamental, first overtone and combination excitations of formaldehyde as well as for the fundamental transitions of ethylene.     

Analysis of oversulfation in a chondroitin sulfate oligosaccharide fraction from bovine aorta by nanoelectrospray ionization quadrupole time-of-flight and fourier-transform ion cyclotron resonance mass spectrometry

A combination of negative ion nano-electrospray ionization Fourier-transform ion cyclotron resonance and quadrupole time-of-flight mass spectrometry was applied to analysis of oversulfation in glycosaminoglycan oligosaccharides of the chondroitin sulfate type from bovine aorta. Taking advantage of the high-resolution and high mass accuracy provided by the FT-ICR instrument, a direct compositional assignment of all species present in the mixture can be obtained. An oligosaccharide fraction containing mainly hexasaccharides exhibited different levels of sulfation, indicated by the presence of species with regular sulfation pattern as well as oversulfated oligosaccharides with one additional sulfate group. Oversulfation can be directly identified from the high-resolution/high mass accuracy FT-ICR mass spectra according to their specific isotopic fine structure. Location of sulfate groups was analyzed by Q-TOF MS and low-energy CID MS/MS. Tetrasulfated hexasaccharides were analyzed by use of collision-induced dissociation at variable collision energy for an unambiguous assignment of the attachment site of the sulfate groups by minimizing unspecific neutral losses. Cleavage of glycosidic bonds gave rise to B- and C-type ions and their respective complementary Y- and Z-type fragment ions.     

Application of the crack resistance concept to the toughness characterization of high-impact thermoplastics

Heterophasic reactor-grade polypropylene-ethylene copolymers were diluted with a propylene-ethylene random copolymer to obtain materials with a constant EPR/PE-particle diameter but various interparticle distances. In addition to these copolymers, PP/EPR blends were investigated. According to the results of instrumented impact tests, brittle-to-tough transitions were found at different temperatures. In the materials with PP matrix, two transitions in the load-deflection behaviour were seen. The first transition occurs from the elastic to the elastic-plastic material behaviour, the second from the unstable to stable crack growth. “Critical” interparticle distances could be determined in the region of predominantly unstable crack growth as well as in the region of predominantly stable crack growth. With increasing test temperature, both transitions shift to higher interparticle distances. From this theoretically similar behaviour of fracture mechanical values quantifying different proportions of the crack growth process, one can conclude that different processes must be occurring.     

Efficient iron-mediated approach to pyrano[3,2-a]carbazole alkaloids--first total syntheses of O-methylmurrayamine A and 7-methoxymurrayacine, first asymmetric synthesis and assignment of the absolute configuration of (-)-trans-dihydroxygirinimbine

Iron-mediated oxidative cyclisation provides an efficient approach to pyrano[3,2-a]carbazole alkaloids. Thus, improved routes to girinimbine and murrayacine as well as the first total syntheses of O-methylmurrayamine A and 7-methoxymurrayacine are reported. Asymmetric epoxidation of girinimbine led to (-)-trans-dihydroxygirinimbine and the assignment of its absolute configuration.