Gezielte synthese dreikerniger heterometall-cluster mit vier verschiedenen gerüstatomen

The trinuclear heterometallic clusters Va—Vc possessing a tetrahedral framework of four different atoms (MPdPtC) have been prepared from (μ-2-MeC₃H₄)(μ-Br)PdPt(PPrⁱ₃)₂ (IV) and [C₅H₅(CO)₃M]Na (M = Cr, Mo, W). Complex IV is obtained from (μ-2-MeC₃H₄)(μ-C₅H₅)PdPt(PPrⁱ₃)₂ and Me₃SiBr by bridge—ligand exchange. Following the same concept, the synthesis of the Pt₂Mo and Pt₂W heterometallic clusters VIIIa, VIIIb has also been achieved.     

On the quark mass dependence of the parameters of quantum chromodynamics

The running coupling constant and quark masses in QCD are calculated in the one-loop approximation using the 3-gluon vertex to define the coupling constant. Our results differ for finite quark masses from those reported previously in the literature. We discuss the origin of this apparent discrepancy. We also make some comments on the gauge dependence of the QCD parameters.     

Zur Kondition des linearen Ausgleichsproblems mit linearen Gleichungen als Nebenbedingungen

Summary F.L. Bauer has treated in several papers [1, 3, 4] the condition related to the solution of linear equations and to the algebraic eigenvalue problem. We study the condition for the linear least squares problem with linear equality constraints (problem LSE). A perturbation theory of problem LSE is presented and three condition numbers are defined. Problem LSE includes the linear least squares problem (problem LS). There are examples with identical solution of problem LSE and of problem LS. Sometimes the condition of problem LSE is better and sometimes the condition of problem LS is better. Several numerical tests illustrate the theory.

Herrn Prof. Dr. Dr. F.L. Bauer zum 60. Geburtstag gewidmet     

Pseurotin B,C, D,and E. Further New Metabolites of Pseudeurotium ovalis STOLK

The structures 2–5 are assigned to the pseurotin B, C, D and E, which are new metabolites of Pseudeutorium ovalis STOLK , based on spectroscopic data and chemical transformations.     

Abschnittskonvergenz und Umkehrsätze beim Euler-Verfahren

Ohne ZusammenfassungViktor Garten zum Gedenken     

Isotachophoresis as a useful tool for monitoring neurological complications of acute leukaemia in children

Cerebrospinal fluid proteins from 42 children with acute lymphoblastic leukaemia were analysed by isotachophoresis. The isotachopherograms of cerebrospinal fluid taken from patients undergoing central nervous system prophylaxis with neurological complications showed an increase of several peaks (albumin, prealbumin, and an unidentified peak), and changes in the globulin zone, compared with those from patients who had completed central nervous system prophylaxis for at least six months. The most striking finding was that these alterations were not associated with any other biochemical changes in the cerebrospinal fluid, as assayed by routine analysis. Isotachophoresis may be useful in the monitoring of therapy in children affected with acute lymphoblastic leukaemia.