1-N-acylation of aminocyclitol antibiotics via zinc chelation and regiospecific N-trifluoroacetylation

Amikacin and 1-N-[(S)-4-amino-2-hydroxybutyryl]-3′,4′-dideoxykanamycin B have been prepared from kanamycin A and dibekacin by a novel, efficient sequence of reactions involving complex formation with Zn²⁺ and regiospecific N-trifluoroacetylation using ethyl trifluoroacetate.     

Thermogravimetric Analysis of Aromatic Polyamides with Various Benzimidazolyl Contents

The TG analyses are given for variously meta- and/or para-linked aromatic polyamides with various benzimidazolyl (BI)contents. The TG curves of the polymers were evaluated within 600°C by use of an equation for multiple events. The TG curves of BI-substituted polymers are expressed for triple events, though the TG curves of unsubstituted polymer are expressed for double events. The amount of residue of BI-substituted polymers at 800°C is larger than that of unsubstituted polymers, perhaps because moieties concerning BI degrade at higher temperatures. This revised version was published online in July 2006 with corrections to the Cover Date.     

Laser-induced luminescence from an excited HgNH3 complex

When a Hg/NH₃ mixture is irradiated at 260 nm or longer wavelengths luminescence appears around 340 nm. The luminescence originates from an excited HgNH³ complex formed through a bound—free transition. Both the luminescence excitation spectrum and the dispersed spectrum have been analysed in terms of postulated potentials for the ground and excited-state HgNH₃ complexes.     

High performance liquid chromatographic analysis of time-dependent changes in urinary excretion of indoleamines following tryptophan administration

Analytical conditions of prepurification extraction and HPLC separation were optimized for determination of urinary serotonin and tryptamine. Under optimal conditions, serotonin, tryptamine and an internal standard were extracted with 15% v/v n-propanol in diethyl ether from urine samples alkalized with a phosphate buffer (0.75 mol/L, pH 10.0), and then they were re-extracted into an HCl solution (0.1 mol/L). Purified indoleamines were simultaneously separated by reversed-phase ion-pair HPLC with native fluorescence detection. Urinary serotonin and tryptamine were selectively determined within about 45 min per sample for the whole procedure. Analytical recovery, reproducibility and detection sensitivity were satisfactory for pursuing time-dependent changes in indoleamine levels. Urinary excretion profiles of serotonin and tryptamine in subjects dosed with L-tryptophan were successfully analyzed by our method.     

Vertex operators in the conformal field theory on P 1 and monodromy representations of the braid group

Vertex operators (primary fields) are constructed for the conformal field theory on P ¹ by means of A ₁ ⁽¹⁾ modules. The commutation relations of vertex operators induce monodromy representations of the braid group on the spaces of vacuum expectations of compositions of vertex operators.     

Photochemical arylation by oxime esters in benzene and pyridine: simple synthesis of biaryl compounds

Irradiation of benzophenone O-arenecarbonyloximes in benzene and pyridine affords the corresponding arylbenzenes and arylpyridines, respectively, in high yields.     

Use of an immobilized glucose oxidase cation-exchange resin column in the determination of glucose

A thermal flow system for glucose determination is described, that utilizes a column of glucose oxidase immobilized on a cation-exchange resin (Amberlite CG50). The response is linear for glucose concentrations in the range 0.01-0.4mM. Stability and the factors influencing the response have been examined.     

An in situ RBS system for measuring nuclides adsorbed at the liquid-solid interface

An in situ RBS system has been developed for measuring heavier nuclides adsorbed at the inner surface of a thin lighter window specimen of a liquid container in order to determine the rate constants for their sorption and release at the liquid-solid interface. The tolerance of a thin silicon window of the sample assembly, in which Xe gas of one atmosphere is enclosed, against the bombardment of the probing ion beam has been tested. A desorption behaviour of a lead layer adsorbed at the SiO₂ surface layer of the silicon window into deionized water has been measured as a preliminary experiment.