Transitivity conditions in infinite graphs

We study transitivity properties of graphs with more than one end. We completely classify the distance-transitive such graphs and, for all k≥3, the k-CS-transitive such graphs.     

Carleson's counterexample and a scale of Lorentz-BMO spaces on the bitorus

We introduce a full scale of Lorentz-BMO spaces BMO _L ^p,q on the bidisk, and show that these spaces do not coincide for different values ofp andq. Our main tool is a detailed analysis of Carleson's construction in [C]. The first author gratefully acknowledges support by the LMS and Proyecto BFM2002-04013. The second author gratefully acknowledges support by EPSRC and by the Nuffield Foundation.     

Ueber die Verbindung der Eiweissk?rper mit Kupferoxyd

Ohne Zusammenfassung     

The mann test for divisible difference sets

Generalizing a result of Jungnickel for affine difference sets, we present an existence test for arbitrary divisible difference setsD which is analogous to the well-known and powerful test of Mann for ordinary difference sets. Several applications show that this approach is of interest also in the general case.Research partially supported by NSA grant # MDA 904-87-H-2018 and by an Alexandervon-Humboldt fellowship. The author would like to thank the Mathematisches Institut der Justus-Liebig-Universität Giessen for its hospitality during the time of this research.     

Luminescence of Mn ions in ordered and disordered LiAl5O8

The phosphorescence and excitation spectra of Mn ions in the ordered and disordered phases of LiAl₅O₈ have been measured. In both phases Mn²⁺ ions substitute for Al³⁺ ions in two different tetrahedral sites of the LiAl₅O₈ lattice. In both sites in the ordered phase, sharp zero-phonon transitions have been observed in the low temperature phosphorescence and excitation spectra - these transitions were considerably broadened in the disordered phase due to crystal field inhomogeneity in that phase. The deviation from neutrality caused by the Mn²⁺ ions in the ordered phase is largely compensated by Mn⁴⁺ ions occupying octahedral Al³⁺ sites. On disordering, a large proportion of Mn⁴⁺ is reduced to Mn²⁺, while the remainder takes up a site with a higher proportion of Li⁺ ions as next nearest neighbours. This leads to an increase in the ionicity of the Mn⁴⁺ site in the disordered phase and hence to a larger value of the Racah parameter B.     

On abelian difference sets with multiplier — 1

Archiv der Mathematik -     

Optical conductivity of CePd3, YPd3 and PrPd3

The optical conductivity of intermediate valence CePd₃ at 300 K exhibits a maximum near 16 meV, which is absent in the reference materials YPd₃ and PrPd₃. Using a modified Drude model with a memory function ansatz this anomaly has been identified as a resonant electron-electron scattering process of conduction electrons at the localized 4f states near the Fermi level E_F. The model fit gives estimates of the width of the 4f states, of their separation from E_F and of the f-d hybridization energy. Intra-4f transitions of CePd₃ are stronger compared to those of PrPd₃ due to the stronger f-d hybirdization. 4d→4f transition energies of CePd₃ are reduced due to an electron-hole Coulomb binding energy.     

Nanoscale coordination polymers for platinum-based anticancer drug delivery

Pt-containing nanoscale coordination polymer (NCP) particles with the formula of Tb2(DSCP)3(H2O)12 (where DSCP represents disuccinatocisplatin), NCP-1, were precipitated from an aqueous solution of Tb3+ ions and DSCP bridging ligands via the addition of a poor solvent. SEM and TEM images showed that as-synthesized NCP-1 exhibited a spherical morphology with a DLS diameter of 58.3 +/- 11.3 nm. NCP-1 particles were stabilized against rapid dissolution in water by encapsulation in shells of amorphous silica. The resulting silica-coated particles NCP-1' exhibited significantly longer half-lives for DSCP release from the particles (a t1/2 of 9 h for NCP-1' with 7 nm silica coating vs t1/2 of 1 h for as-synthesized NCP-1). In vitro cancer cell cytotoxicity assays with the human colon carcinoma cell line (HT-29) showed that internalized NCP-1' particles readily released the DSCP moieties which were presumably reduced to cytotoxic Pt(II) species to give the Pt-containing NCPs anticancer efficacy superior to the cisplatin standard. The generality of this degradable nanoparticle formulation should allow for the design of NCPs as effective delivery vehicles for a variety of biologically and medically important cargoes such as therapeutic and imaging agents.