Zur Kenntnis des Härtungsprozesses von Phenol-Formaldehyd-Harzen

Zusammenfassung Durch Hydrierung, Abbau und durch Vergleich des Verhaltens linearer Mehrkernverbindungen bei diesen Reaktionen wurde neuerdings experimentell geprüft, ob die annahme, daß gewisse Härtungsprodukte von Phenolalkoholen cyclische Struktur besitzen, zutrifft.     

The determination of the magnetic structure of DyCrO4 by neutron diffraction

At room temperature DyCrO₄ has the tetragonal zircon structure. Susceptibility measurements show that DyCrO₄ is ferromagnetic below 23 K. Neutron diffraction from a powder sample yield the magnetic structure. Using a computer program, which was developed for the determination of non-collinear and spiral structures, several models allowed by symmetry were compared with the experiment. It turns out that the Dy-moments and the Cr-moments as well order parallel in the a-b-plane. For the Dy-moment a value of 12μ_B and for the ratio of the Cr- to the Dy-moment a value of $\text{1}\text{10}$ was found.     

Magnetic properties of the cerium monochalcogenides

Single crystals of CeS, CeSe and CeTe have been investigated by means of measurements of the specific heat, the thermal expansion, the magnetic susceptibility and the magnetization at low temperatures. Crystal-field effects on some of these properties are used to derive the crystal-field splitting of the 4f electron ground state. It is found that chemical composition and crystal perfection strongly influence the magnetic properties of these compounds.     

Synthesis of deuterated methyl 2,3,4,6-Tetra-o-methyl-β-d-galactopyranosides

Conclusions We have synthesized methyl 2,3,4,6-tetra-O-methyl--D-galactopyranosides selectively labeled with deuterium in positions 1–6 with deuterium content >90%.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 192–195, January, 1978.     

Synthesis of polysaccharides. Communication 15. Synthesis of β-(1 → 6)-D-galactan

Conclusions 1,2-0-(1-exo-Cyano)ethylidene-3,4-di-0-acety1-6-0-trityl- and 1,2-0-(1-exo-cyano)ethylidene-3,4-di-0-benzoyl-6-0-trityl--D-galactopyranoses were synthesized. Their polycondensation led to D-galactans, which do not contain -glycoside bonds.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya., No. 10, pp. 2358–2363, October, 1984.     

Scale dependence of branching in arterial and bronchial trees

Although models of branching in arterial and bronchial trees often predict a dependence of bifurcation parameters on the scale of the bifurcating vessels, direct verification of this dependence by comparison with data is uncommon. We compare measurements of bifurcation parameters of airways and arterial trees of different mammals as a function of scale to general features predicted by theoretical models based on minimization of pumping power and network volume. We find that the size dependence is more complex than existing theories based solely on energy and volume minimization explain, and suggest additional factors that may govern the branching at different scales.     

Spectral theory and iterative methods for the Maxwell system in nonsmooth domains

We study spectral properties of boundary integral operators which naturally arise in the study of the Maxwell system of equations in a Lipschitz domain Ω ? ?³. By employing Rellich‐type identities we show that the spectrum of the magnetic dipole boundary integral operator (composed with an appropriate projection) acting on L²(?Ω) lies in the exterior of a hyperbola whose shape depends only on the Lipschitz constant of Ω. These spectral theory results are then used to construct generalized Neumann series solutions for boundary value problems associated with the Maxwell system and to study their rates of convergence (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

A new mechanism for gravitational-wave emission in core-collapse supernovae

We present a new theory for the gravitational-wave signatures of core-collapse supernovae. Previous studies identified axisymmetric rotating core collapse, core bounce, postbounce convection, and anisotropic neutrino emission as the primary processes and phases for the radiation of gravitational waves. Our results, which are based on axisymmetric Newtonian supernova simulations, indicate that the dominant emission process of gravitational waves in core-collapse supernovae may be the oscillations of the protoneutron star core. The oscillations are predominantly of mode character, are excited hundreds of milliseconds after bounce, and typically last for several hundred milliseconds. Our results suggest that even nonrotating core-collapse supernovae should be visible to current LIGO-class detectors throughout the Galaxy, and depending on progenitor structure, possibly out to megaparsec distances.     

Evaluation of Ruthenium(II) N-Heterocyclic Carbene Complexes as Antibacterial Agents and Inhibitors of Bacterial Thioredoxin Reductase

A series of ruthenium(II) complexes with N-heterocyclic carbene (NHC) ligands of the general type (arene)(NHC)Ru(II)X₂ (where X = halide) was prepared, characterized, and evaluated as antibacterial agents in comparison to the respective metal free benzimidazolium cations. The ruthenium(II) NHC complexes generally triggered stronger bacterial growth inhibition than the metal free benzimidazolium cations. The effects were much stronger against Gram-positive bacteria (Bacillus subtilis and Staphylococcus aureus) than against Gram-negative bacteria (Escherichia coli, Acinetobacter baumannii, Pseudomonas aeruginosa), and all complexes were inactive against the fungus Candida albicans. Moderate inhibition of bacterial thioredoxin reductase was confirmed for selected complexes, indicating that inhibition of this enzyme might be a contributing factor to the antibacterial effects.