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41.
Marie-Louise Wind Beatrice Braun-Cula Fabian Schax Christian Herwig Prof. Christian Limberg 《Israel journal of chemistry》2020,60(10-11):1057-1060
The isolation and identification of intermediates formed in the course of the activation of dioxygen at transition metal centers reveals important mechanistic insights concerning such processes. We previously reported the reaction of the dinuclear CrII complex [L2Cr2(MeCN)2][Li(MeCN)]2 (L=PhSi(OSiPh2O−)3) ( 5 ) with dioxygen, which resulted in the formation of the CrIV oxo complex [L2Cr2O2][Li(THF)2]2 ( 6 ), as the final room temperature stable product. Here we now report the isolation and characterization of an intermediate en route to 6 , namely the dinuclear CrIII superoxo complex [L2Cr2(O2)2][Li(MeCN)]2 ( 7 ). 7 is the first example of a structurally characterized dinuclear CrIII superoxo complex with two independent side-on bound superoxo ligands. Reactivity studies outline the capability of this superoxo complex to activate weak O−H bonds. 相似文献
42.
Allie E. Auld Fabian Mueller Keyue Ma Smedley Scott Samuelsen Jack Brouwer 《Journal of power sources》2008
Adding distributed generation (DG) is a desirable strategy for providing highly efficient and environmentally benign services for electric power, heating, and cooling. The interface between a solid oxide fuel cell (SOFC), typical loads, and the electrical grid is simulated in Matlab/Simulink and analyzed to assess the interactions between DG and the electrical grid. A commercial building load profile is measured during both steady-state and transient conditions. The load data are combined with the following models that are designed to account for physical features: a One-Cycle Control grid-connected inverter, a One-Cycle Control active power filter, an SOFC, and capacitor storage. High penetration of DG without any power filter increases the percentage of undesirable harmonics provided by the grid, but combined use of an inverter and active power filter allows the DG system interconnection to improve the grid tie-line flow by lowering total harmonic distortion and increasing the power factor to unity. 相似文献
43.
MO-LCAO Calculations on Polymethines. XI. Local Spectral Excitations in Polynuclear Cyanine Dyes Various branched-conjugated cyanine dyes display long-wavelength absorption bands similar in position to those of their straight-chain substructures. According to the analysis of results of PPP-type calculations this close similarity results from a partial localization of the electronic transitions, whereas the participating electronic states are highly delocalized. The long-wavelength absorptions of symmetrically-branched trinuclear cyanine dyes have an entire molecular chromophore origin resulting from twofold degenerate electronic transitions. Lowering of the symmetry brings about a splitting of the colour-band. In contrast to the branched-conjugated cyanine dyes various tetranuclear cyanine dyes can be considered as being composed of two subchromophores either directly linked or joined through a conjugative bridge. In accordance with PPP configuration analyses and LHM-type calculations the splitting of the colour band is best understood by composite-molecule approaches. In this context the applicability of the simple molecular exciton theory is discussed. 相似文献
44.
45.
Patrick J. Riss Dr. Fabian Debus Dr. René Hummerich Ulrich Schmidt Dr. Patrick Schloss Dr. Hartmut Lueddens Dr. Frank Roesch Dr. 《ChemMedChem》2009,4(9):1480-1487
N‐4‐Fluorobut‐2‐yn‐1‐yl‐2β‐carbomethoxy‐3β‐phenyltropane (PR04.MZ) has been developed as dopamine transporter (DAT) ligand for molecular imaging. It contains a terminally fluorinated, conformationally constrained nitrogen substituent that is well suited for the introduction of fluorine‐18. The present report describes the pharmacological characterisation of [18F]PR04.MZ. The ligand shows an IC50 value of 2 nM against human DAT, whereas the IC50 value against human serotonin transporter and human noradrenalin transporter are lower (110 nM and 22 nM , respectively). Furthermore, its ex vivo organ distribution, its binding profile in the rat brain and reversibility of binding were examined. A μPET study illuminates a fast kinetic profile and specific binding to rat DAT. 相似文献
46.
An implementation of locally adaptive penalized spline smoothing using a class of heavy-tailed shrinkage priors for the estimation of functional forms with highly varying curvature or discontinuities is presented. These priors utilize scale mixtures of normals with locally varying exponential-gamma distributed variances for the differences of the P-spline coefficients. A fully Bayesian hierarchical structure is derived with inference about the posterior being based on Markov Chain Monte Carlo techniques. Three increasingly flexible and automatic approaches are introduced to estimate the spatially varying structure of the variances. An extensive simulation study for Gaussian, Poisson, and Binomial responses shows that the performance of this approach on a number of benchmark functions is competitive to that of previous approaches. Results from applications with Gaussian and Poisson responses support the simulation results. 相似文献
47.
Dominik M. Wittmann Daniel Schmidl Florian Blchl Fabian J. Theis 《Theoretical computer science》2009,410(38-40):3826-3838
The analysis of complex networks is of major interest in various fields of science. In many applications we face the challenge that the exact topology of a network is unknown but we are instead given information about distances within this network. The theoretical approaches to this problem have so far been focusing on the reconstruction of graphs from shortest path distance matrices. Often, however, movements in networks do not follow shortest paths but occur in a random fashion. In these cases an appropriate distance measure can be defined as the mean length of a random walk between two nodes — a quantity known as the mean first hitting time.In this contribution we investigate whether a graph can be reconstructed from its mean first hitting time matrix and put forward an algorithm for solving this problem. A heuristic method to reduce the computational effort is described and analyzed. In the case of trees we can even give an algorithm for reconstructing graphs from incomplete random walk distance matrices. 相似文献
48.
Fabian Heinemann Meike Gummich Manfred Radmacher Monika Fritz 《Materials science & engineering. C, Materials for biological applications》2011,31(2):99-105
Mineral growth in nacre and other CaCO3-containing biominerals is controlled by biopolymers. Water-soluble proteins were extracted from nacre of the sea snail Haliotis laevigata by dissolving the mineral phase with 6% acetic acid. The influence of this protein mixture on CaCO3 precipitation rates was investigated at different concentrations. A well-established assay for measuring the pH-value during CaCO3 precipitation with and without protein additives was extended by calculating maximum precipitation rates from the pH-values. It could be shown that precipitation rates are greatly influenced by the mixtures of water-soluble nacre proteins. At very low protein concentrations (0.02 μg/ml) a rate enhancement in comparison to the pure supersaturated calcium carbonate solution by a factor of 1.4 was observed. At higher protein concentrations, a strong inhibitory effect occurred, with total inhibition at concentrations of 1.0 μg/ml and higher. Two unspecific proteins (bovine serum albumin and lysozyme) showed little or no modification of precipitation rates. In vivo, the function of the strong inhibition of CaCO3 precipitation by nacre proteins at higher concentrations is presumably to prevent uncontrolled crystallization in the extrapallial fluid. The rate-enhancing capability of proteins at low concentrations may be explained by the presence of acidic and/or hydrophilic moieties. 相似文献
49.
Andrea D Lehmann Fabian Blank Oliver Baum Peter Gehr Barbara M Rothen-Rutishauser 《Particle and fibre toxicology》2009,6(1):26
Background
Using an in vitro triple cell co-culture model consisting of human epithelial cells (16HBE14o-), monocyte-derived macrophages and dendritic cells, it was recently demonstrated that macrophages and dendritic cells create a transepithelial network between the epithelial cells to capture antigens without disrupting the epithelial tightness. The expression of the different tight junction proteins in macrophages and dendritic cells, and the formation of tight junction-like structures with epithelial cells has been demonstrated. Immunofluorescent methods combined with laser scanning microscopy and quantitative real-time polymerase chain reaction were used to investigate if exposure to diesel exhaust particles (DEP) (0.5, 5, 50, 125 μg/ml), for 24 h, can modulate the expression of the tight junction mRNA/protein of occludin, in all three cell types. 相似文献50.
Fabian C. Hadipriono Richard E. Larew Barry Wong 《Civil Engineering and Environmental Systems》2013,30(2):99-103
This paper demonstrates the use of a rule-based weighted rating system (RWRS) developed for improving the rating of concrete culverts. RWRS combines the qualitative rating based on a guideline commonly used by the Department of Transportation, the quantitative rating based on a regression model, and the inspector's own judgment on the culvert's rating. Weight on each rating is provided by the supervisor. A case study is presented to demonstrate the use of RWRS. 相似文献