234 research outputs found
Mono-, di-, and trimetallic complexes of the nonalternating polycondensed pi-perimeter decacyclene, C36H18: Synthesis, structure, and spectroelectrochemistry of [{(eta(5)-Me4EtC5)Co}(2)(mu-eta(5):eta(4)-C36H18)]
No full textReaction of the half-sandwich complexes [(eta (5)-Me4RC5)M(eta (2):O-acac)] (M = Co, Ni; R = Me or Et) with di- and trianions of the polycondensed pi -hydrocarbon decacyclene results in formation of the first Co and Ni triple-decker complexes of this hydrocarbon. For the title compound NMR spectra as well as a crystal structure analysis reveal an antarafacial coordination of two {(eta (5)-Me4EtC5)Co] fragments at the central six-membered ring and one of the neighboring five-membered rings of decacyclene. The bridging pi -perimeter decacyclene displays a bowl-shaped topology. In the case of Ni, coordination of two {(eta (5)-Me5C5)Ni} fragments at the central six-membered ring of decacyclene is observed, based on the results of H-1 and C-13 NMR studies. This coordination mode is without precedent for nickel organometallic compounds reported so far. The cobalt complex shows a rich spectroelectrochemistry. Results of cyclic voltammetry and coupled ESR experiments reveal a strong interaction of both metal centers in the mixed-valent monocation of [{(eta (5)-Me4EtC5)-Co}(2)(mu-eta (5):eta (4)-C36H18)]. This categorizes the title compound into Robin Day class III
Applications of a numerical model for slow moving landslides to the Valoria landslide in the Italian Apennines, and the Super Sauze mudslide in the French Alps
No full textISBN 2-95183317-1-5This research demonstrates the applicationof the dynamic SLOWMOVE model onthe Valoria case study located in the northern Apennines (Italy) and the Super-Sauze landslide in the southwestern Alps (France). The SLOWMOVE model is based on the Navier-Stokes equations. The landslide is modeled as a one-phase material with homogeneous and constant rheological properties. The slow movements of landlside materials allow for the cancellation of the inertia term from the momentum equation. At the Valoria case study site a 3.5 km long earth slide/flow with materials comprised of disaggregated Flysch, Marl and Clay-stones resumed activity in 2001 after a suspended phase. The landslide is characterized as earth slides in the upper slope, and as earth flows in the main track following complete disaggregation of the materials in the source areas. During reactivations, the earth flows can reach velocities up to 10 m·h-1. Characteristic for the landslide activity are repeated acceleration events ascribed to seasonal climatic inputs. Through continuous activity since 2001, more than 15 million cubic meters of material have been transferred down-slope. The Su-per-Sauze landslide is triggered in Callovo-Oxfordian black marls and is composed of a silty-sand matrix mixed with moraine debris. It extends over a horizontal distance of 850 m with an average slope of 25° impli-cating a volume of 560,000 m3. The complex paleo-topography covered by the landslide is made by succes-sions of crests and gullies which play an essential role in the mudslide behavior by creating sections with dis-tinct kinematical, mechanical and hydrological characteristics. The mudslide kinematics is characterized by a spatially heterogeneous displacement field with velocities ranging from 0.01 to 0.40 m day-1. For the Valoria landslide, the performance of the 1D approach of SLOWMOVE was analyzed on a representative landslide cross-section from the main track zone down to the toe zone. Multi-temporal Lidar surveys in conjunction with a large set of surface displacement data obtained from continuous monitoring since March 2008 was used to calibrate and evaluate the SLOWMOVE model. The model is capable to simulate realistic velocities and displacements but failed to achieve an accurate topographic reconstruction of the morphologic changes between 2003 and 2007. For the Super Sauze mudslide, the 2.5 D approach is used to simulate the heteroge-neous displacement field of the mudslide. The performance of the model is evaluated on multi-temporal and spatially distributed datasets of landslide displacements for the period of summer 200
The State of Carbohydrate and Lipid Metabolism in as in Women
No full textFree radical processes with the development of oxidative stress stimulate the expression of cytokines by T-lymphocytes and macrophages, are able to inhibit endothelium-dependent vasodilation (ESVD) of blood vessels and cause vasoconstrictor reactions [Landmesser U., Spickermann S., Dikalov S. et al., 2002; Davignon I., Ganz P., 2004; Lubos E., Handy D.E., Loscalzo D., 2005]
Lukian von Samosata und die Volksversammlungen
No full textАвтор раскрывает использование понятия «экклесия» («народное собрание») в произведениях Лукиана. The author describes the use of the concept "ecclesia" ("popular assemblies") in the works of Lucian
Messung der Temperaturabhangigkeit der Driftkammergeschwindigkeit von Elektronen in verschiedenen Zahlgasen
No full textA pi-stacked organometallic propeller: Experimental and theoretical studies on reactivity and bonding in the pi-arene-bridged nickel triple-decker [{(eta(5)-Me4EtC5)Ni}(2)(mu-eta(3):eta(3)-decacyclene)]
No full textSynthesis, structure, reactivity, and theoretical studies of a new type of Ni triple-decker complexes are reported. A prominent feature of its molecular structure is the (eta (3):eta (3))-bis- (enyl) coordination of two [(eta (5)-Me4EtC5)Ni] fragments to the central arene ring of the polycondensed pi -perimeter decacyclene. The central arene ring of decacyclene displays a distinct chair conformation with significant tilt angles of 25.5 and 26.1 degrees. The three naphthalene units are twisted in a propeller-like fashion with torsion angles of 16 degrees, 16.6 degrees, and 19 degrees, which is twice the twisting observed for the free decacyclene ligand. According to Extended Huckel Molecular Orbital (EHMO) calculations, a qualitative measure for arene lability in the title compound and a number of related arene-bridged metal complexes can be attributed to a subsequent filling of metal-arene antibonding orbitals. The experimentally observed reactivities of R-arene exchange in these complexes are reproduced nicely by the EHMO calculations. The title compound offers access to a number of organonickel chalcogenato complexes under mild conditions by cleavage of the S-S, Se-Se, or Te-Te bonds of diorganyl dichalcogenides R-E-E-R. The title compound is also capable of C-sp2-H activation of azobenzene and [ (dimethylamino)methyl] ferrocene resulting in orthometallated complexes containing five-membered metallacycles. PES and semi-empirical ZINDO/S calculations were used to study the product of the orthometallation of the title compound with azobenzene. These studies reveal that the HOMO of the metallacycle (IE = 6.45 eV) has dominant Ni-Cp and Ni-C-aryl pi -antibonding character
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