A Helson-Lowdenslager-deBranges Theorem in

This paper presents a generalization of the invariant subspace theorem of Helson and Lowdenslager along the lines of de Branges' generalization of Beurling's theorem.

     

Matrix-valued interpolation and hyperconvex sets

We prove that it is possible for two uniform algebras to have the same scalar interpolating sets, yet still have different matrix-valued interpolating sets.We prove a result for tensor products of uniform algebras that extends Agler's interpolation formula for the bidisk to more general product domains. This is accomplished by introducing a dual object for interpolation problems, which we call a Schur ideal, and proving that the Schur ideal for a tensor product is the intersection of the corresponding Schur ideals.Research supported in part by a grant from the NSF     

Beiträge zur Koordinationschemie von Rhenium(III)chlorid in nichtwäßrigen Lösungen

Coordination reactions of solutions of Re₃Cl₉ in acetonitrile, propanediol-1,2-carbonate, acetone and dimethylsulfoxide yield compounds with unchanged metal-cluster structures. The following compounds were isolated and characterised: [Et ₄N]₃[Re₃Cl₉(N₃)₃], [Et ₄N]₃[Re₃Cl₆(N₃)₆], [Et ₄N]₃[Re₃Cl₃(N₃)₉], [Et ₄N]₃[Re₃Cl₉(CN)₃], [Et ₄N]₃[Re₃Cl₃(CN)₉],Et ₄N]₃[Re₃Cl₉(NCS)₃], [Et ₄N]₃[Re₃Cl₆(NCS)₆], [Et ₄N]₃[Re₃Cl₃(NCS)₉], Re₃Cl₉·(DMSO)₃, Re₃Cl₉·(HMPT)₃.     

Comparative analytical quantitation of clenbuterol in biological matrices using GC-MS and EIA

A simple and sensitive procedure utilizing GC-MS for the identification and quantitation of clenbuterol in biofluids and tissues is described. This improved method utilizes trimethylboroxine for the derivatization of clenbuterol, requires only 1 mL/g of biological sample, and most importantly does not require an extra cleaning step for urine specimens prior to extraction. Linear quantitative response curves have been generated for derivatized clenbuterol over a concentration range of 5-200 ng/mL. The extraction efficiency at four representative points of the standard curve exceeded 90% in both specimen types (plasma and urine). Linear regression analyses of the standard curve in both specimen types exhibited correlation coefficients ranging from 0.997 to 1.000. The Limit of detection (LOD) and Limit of quantitation (LOQ) values for plasma specimens were determined to be 0.5 and 1.5 ng/mL respectively. For urine specimens, LOD and LOQ values were 0.2 and 0.7 ng/microL respectively. Percentage recoveries ranged from 91 to 95% for urine and 89 to 101% for plasma. Precision and accuracy (within-run and between-run) studies reflected a high level of reliability and reproducibility of the method. In addition to its reliability, sensitivity and simplicity, this modified procedure is more efficient and cost effective, requiring less time, only 1 mL of sample, and minimal amounts of extraction solvents. The applicability of the method for the detection and quantitation of clenbuterol in biological tissues of rats treated with the drug was demonstrated successfully. For comparative analysis of clenbuterol in plasma and liver samples, both GC-MS and enzyme immunoassay (EIA) methods are found to be suitable. Due to potential antibody-cross reactivity with EIA, the GC-MS method is the method of choice for most samples because of its specificity. However, the EIA method is considered the method of choice for analysis of clenbuterol found in concentrations below the limits of quantitation by GC-MS due to its sensitivity.     

Synthese von oligosaccharid-determinanten des T-antigens mit amid-spacer zur darstellung synthetischer antigene

The β (1 → 3) -linked disaccharide $\text{1}$$\text{5}$ was synthesized from $\text{D}$-galactose and a $\text{D}$-galactosamine unit with a watersoluble amide spacer. This represents the hapten of T-antigen and, when coupled to a protein, is suitable for use as an artificial antigen. Other O-β-$\text{D}$-galactosylated derivatives of galactosamine were synthesized.