Bulk-driven nonequilibrium phase transitions in a mesoscopic ring

We study a periodic one-dimensional exclusion process composed of a driven and a diffusive part. In a mesoscopic limit where both dynamics compete we identify bulk-driven phase transitions. We employ mean-field theory complemented by Monte Carlo simulations to characterize the emerging nonequilibrium steady states. Monte Carlo simulations reveal interesting correlation effects that we explain phenomenologically.     

Exfoliation of hexa-peri-hexabenzocoronene in water

Unsubstituted hexa-peri-hexabenzocoronene (HBC)-a small and well defined model system for graphite/graphene-was exfoliated and dissolved in water and the resulting individualized nano graphene sheets were characterized spectroscopically for the first time.     

Common Fibril Structures Imply Systemically Conserved Protein Misfolding Pathways In Vivo

Systemic amyloidosis is caused by the misfolding of a circulating amyloid precursor protein and the deposition of amyloid fibrils in multiple organs. Chemical and biophysical analysis of amyloid fibrils from human AL and murine AA amyloidosis reveal the same fibril morphologies in different tissues or organs of one patient or diseased animal. The observed structural similarities concerned the fibril morphology, the fibril protein primary and secondary structures, the presence of post-translational modifications and, in case of the AL fibrils, the partially folded characteristics of the polypeptide chain within the fibril. Our data imply for both analyzed forms of amyloidosis that the pathways of protein misfolding are systemically conserved; that is, they follow the same rules irrespective of where inside one body fibrils are formed or accumulated.     

Synthesis of the C59N+ carbocation. A monomeric azafullerene isoelectronic to C60

A heterofullerene isoelectronic to C60 is reported. The azafullerenium cation C59N+ can be isolated in good yield as a carborane salt via the two-electron oxidation of the C-C bond of (C59N)2 dimer. [C59N][Ag(CB11H6Cl6)2] has been characterized by electronic, IR, Raman, and 13C NMR spectroscopies, MALDI spectrometry, DFT calculations, and X-ray crystallography.     

Synthesis and properties in solution of ruthenium(II) coordination polymers

Synthetic strategies are presented for the preparation of readily soluble ruthenium(II) coordination polymers of high molecular weight. The constitutional homogeneity of the polymers is proved using high-resolution NMR spectroscopy, and their molar masses are estimated from ¹H NMR spectra, viscosity data and SAXS investigations. The polymers are shown to be conformationally rigid, and to form either densely packed coils or rods. It is mainly this difference in shape which causes the very specific properties of the respective polyelectrolytes in the solid state as well as in dilute solution. Finally, the UV-vis absorption spectra of some of these materials are presented.     

Zur Elektronenstruktur hochsymmetrischer Verbindungen der f‐Elemente. 38 [1] Kristall‐, Molekül‐ und Elektronenstruktur von Tris(hydrotris(1‐pyrazolyl)borato)‐samarium(III)

Electronic Structures of Highly Symmetrical Compounds of f Elements. 38 [1] Crystal, Molecular and Electronic Structure of Tris(hydrotris(1‐pyrazolyl)borato)samarium(III) Tris(hydrotris(1‐pyrazolyl)borato)samarium(III) (SmTp₃) crystallizes in the space group P6₃/m (No. 176) with two molecules in the unit cell. The Sm³⁺ central ion is coordinated by nine N atoms in the shape of a tricapped trigonal prism, leading to an effective crystal field (CF) of D_3h symmetry. The underlying CF splitting pattern was extracted from the absorption and luminescence spectra run at room and low temperatures, and simulated by fitting the free parameters of a phenomenological Hamiltonian achieving an r.m.s. deviation of 9.4 cm^?1 for 58 assignments. The parameters used allow the estimation of the global ligand field strength experienced by the Sm³⁺ central ion, the insertion of SmTp₃ into empirical nephelauxetic and relativistic nephelauxetic series, and the set‐up of experimentally based nonrelativistic and relativistic molecular orbital schemes in the f range.     

Electronic structure of the high symmetrical compounds of f-element. Part 33. A novel experimental crystallized trigonal-bipyramidal coordinated lanthanide(III) systems: Pr[N(SiMe3)2](CNR)2 (R = tBu, C6H11)]

The absorption und magnetic circular dichroism spectra of the dissolved trigonal-bipyramidal complex Pr[N(SiMe3)2]3(CNtBu)2 (1) as well as the luminescence and absorption spectra of both solid 1 and solid Pr[N(SiMe3)2]3(CNC6H11)2 (2) (pellets, unoriented single crystals) were measured at ambient and low temperatures. Because of the violation of the selection rules for D3h symmetry by both compounds a reliable crystal field(CF) splitting pattern for the ground manifold 3H4, but only a plausible for the f 2 configuration could be derived on the basis of these measurements. The latter could be simulated with a reduced r.m.s. deviation of 32.6 cm(-1) for 29 assignments by fitting the free parameters of a phenomenological Hamiltonian. The adequacy of the calculated wavefunctions of this fit in the low energy range is proved by the excellent agreement of calculated and experimental temperature dependence of mu2(eff) for compound 1. The CF parameters of this fit are considered as a "master set" of CF parameters for future CF analyses of the electronic structures of trigonal bipyramidally coordinated lanthanide(III) systems.     

Mesh adaptivity for the transport equation led by variational multiscale error estimators

Recently, we developed an explicit a posteriori error estimator especially suited for fluid dynamics problems solved with a stabilized method. The technology is based upon the theory that inspired stabilized methods, namely, the variational multiscale theory. The salient features of the formulation are that it can be readily implemented in existing codes, it is a very economical procedure, and it yields very accurate local error estimates uniformly from the diffusive to the advective regime. In this work, the variational multiscale error estimator is applied to develop adaptive strategies for the advection–diffusion‐reaction equation. The performance of L₁ and L₂ local error norms combined with three strategies to adapt the mesh is investigated. Emphasis is placed on flows with sharp boundary and interior layers but also attention is given to diffusion‐dominated flows. Computational results show that the method generates meshes with a smooth transition of the element size, which capture all the flow features. Copyright © 2011 John Wiley & Sons, Ltd.