The Nappi-Witten string in the light-cone gauge

Some of the motivations for as well as the main points of the quantization of the Nappi-Witten string in the light-cone gauge are reviewed.     

Local automorphisms of operator algebras on Banach spaces

In this paper we extend a result of Semrl stating that every 2-local automorphism of the full operator algebra on a separable infinite dimensional Hilbert space is an automorphism. In fact, besides separable Hilbert spaces, we obtain the same conclusion for the much larger class of Banach spaces with Schauder bases. The proof rests on an analogous statement concerning the 2-local automorphisms of matrix algebras for which we present a short proof. The need to get such a proof was formulated in Semrl's paper.

     

On tolerance lattices of algebras in congruence modular varieties

We prove that the tolerance lattice TolA of an algebra A from a congruence modular variety V is 0-1 modular and satisfies the general disjointness property. If V is congruence distributive, then the lattice Tol A is pseudocomplemented. If V admits a majority term, then Tol A is 0-modular. This revised version was published online in June 2006 with corrections to the Cover Date.     

Calculation of cyclodextrin-mediated enantiomer ratio shifting of racem norgestrel in aqueous solutions

Enantioselective solubility of rac-norgestrel was found in the presence of γ-cyclodextrin or hydroxypropyl-γ-cyclodextrin. In both cases the efficacious enantiomer was dissolved in greater extent. Calculating the molar absorptivity and molar ellipticity spectra of the γ- and hydroxypropyl-γ-cyclodextrin aqueous complexes, a simple and rapid direct circular dichroism (CD) spectrometric method was obtained for the determination of the enantiomer ratio in aqueous solutions.     

Two Stage Solid Phase Extraction with Subsequent HPLC Isolation for Structure Elucidation of Major Metabolites of (+)-(R)-2-{3-(benzo[1,4]dioxan-2-yl-methylamino)-1-propyl}-3(2H)-pyridazinone (GYKI-16084)

GYKI-16084 – (+)-(R)-2-{3-(benzo[1,4]dioxan-2-yl-methylamino)-1-propyl}-3(2H)-pyridazinone hydrochloride – is a new drug candidate for the treatment of benign prostatic hyperplasia. In our study the major metabolites formed in the rat and dog were isolated from dog and rat urine, then their structures were elucidated by means of MS and NMR. A two stage solid phase extraction (SPE) procedure and a semi-preparative HPLC method were developed utilizing various mechanisms of separation. The major metabolites proved to be isomeric glucuronides of the benzodioxane moiety hydroxylated at positions 6 or 7 and {2-(2-carboxyethyl)-3(2H)-pyridazinone}.     

Mimicking catalase and catecholase enzymes by copper(II)-containing complexes

An imidazolate-bridged copper(II)-zinc(II) complex (Cu(II)-diethylenetriamino-μ-imidazolato-Zn(II)-tris(2-aminoethyl)amine perchlorate (denoted as “Cu,Zn complex”) and a simple copper(II) complex (Cu(II)-tris(2-aminoethyl) amine chloride (“Cu-tren”) were prepared and immobilised on silica gel (by hydrogen or covalent bonds) and montmorillonite (by ion exchange). The immobilised substances were characterised by FT-IR spectroscopy and their thermal characteristics were also studied. The obtained materials were tested in two probe reactions: catalytic oxidation of 3,5-di-tert-butyl catechol (DTBC) (catecholase activity) and the decomposition of hydrogen peroxide (catalase activity). It was found that the catecholase activity of the Cu,Zn complex increased considerably upon immobilization on silica gel via hydrogen bonds and intercalation by ion exchange among the layers of montmorillonite. The imidazolate-bridged copper(II)-zinc(II) complex and its immobilised versions were inactive in hydrogen peroxide decomposition. The Cu(II)-tris(2-aminoethyl)amine chloride complex displayed good catalase activity; however, immobilisation could not improve it.     

A remark on the Kochen-Specker theorem and some characterizations of the determinant on sets of Hermitian matrices

In this paper we describe the general forms of all (nonlinear) continuous functionals on the sets of positive definite, positive semi-definite and Hermitian matrices which are multiplicative on the commuting elements. As a consequence, we obtain some new characterizations of the determinant on those classes of matrices.

     

Characterization and TLC-Bioautographic Detection of Essential Oils from Some Thymus Taxa. Determination of the Activity of the Oils and their Components Against Plant Pathogenic Bacteria

JPC – Journal of Planar Chromatography – Modern TLC - The chemical composition of the oils of four thyme (Lamiaceae) chemotypes (Thymus vulgaris L., Thymus serpyllum L., Thymus x...