The determination of I, P, B, S, As and Sn by inductively coupled plasma emission spectroscopy using lines at vacuum ultra-violet wavelengths

The application of ICP atomic emission spectroscopy (ICP-AES) for the quantitative determination of I, P, B, S, As and Sn with the aid of their lines between 170 and 200 nm is described. The spectrometer used was kept under vacuum at a pressure below 0.1 Pa and the optical path was purged with Ar gas (99.99% pure) at a flow rate of 3.5 l min⁻¹. The analytical method investigated was applied to the determination of the stated elements in iron and steel and in sea water. No spectral interferences from the close lines of the various concomitants were observed, nor matrix effects from Fe or K, Na, Mg and Ca at the concentration levels found in steel samples or sea water.     

Determination of selenium by atomic absorption spectrometry with miniaturized suction-flow hydride generation and on-line removal of interferences

On-line removal of transition metal interferences in microscale suction-flow hydride generation atomic absorption spectrometry is described for the determination of selenium at μg l^?1 levels. A mini-column of a chelating resin with iminodiacetate groups is used. Selenium in solutions containing ? 2.5 mg of copper or nickel was determined at a rate of 30 samples per hour; the detection limit was 0.1 ng of selenium. The relative standard deviation for ten replicate measurements of 5 ng of selenium was 3.8%. The method was applied successfully to the determination of selenium in standard copper alloys and nickel sponge.     

Optimization of Fe/SiO<Subscript>2</Subscript> based metal oxides as selective oxidation catalyst of propane with combinatorial approach

A combinatorial optimization with genetic algorism was performed on the five generations of 0.05 atm% Fe/SiO₂ added multi-metal oxides to be used as catalytic materials for the selective oxidation of propane to give aldehydes at 623-773 K. The loaded multi-metal oxides consist of some elements selected from seven elements with various atomic charges or redox properties. For the best materials, selectivity toward aldehydes from 35% at 1st generation to 45% at 4th generation were achieved at 5% propane conversion. Further rational optimization of the best performance catalyst also improves the selectivity up to 49.5%.     

On the Gorenstein property of Rees Algebras

Let (A,M) be a noetherian local ring. For certain equimultiple ideals I in A we try to relate the Gorenstein property of the Rees algebraⁿ and of A itself. In particular we n0 treat the case of equimultiple prime ideals of height two and the case I=M. The results underscore a natural conjecture, s. Thm. 2.6. and 3.2.     

The Effects of Cyclodextrins on Autoinducer Activities of Quorum Sensing in Pseudomonas aeruginosa

Inclusion complex formation between cyclodextrin and autoinducer of gram negative bacteria in aqueous solution was investigated by 1D ¹H-NMR and ROESY spectra. An inhibitioneffect was observed on autoinducer activities of quorum sensing in Pseudomonas aeruginosa by adding cyclodextrins to the bacterial culture medium.     

Preferable tautomer of dihydropyrazolo[5, 1-c][1, 2, 4]triazines in solution

Dihydropyrazolo[5, 1-c][1, 2, 4]triazines 6, 7 and 8 were found to predominate as the 4, 6-dihydro tautomeric form in solution by the measurement of ID NOE different spectra.     

Ultraviolet-Laser-Induced Crystallization of Sol-Gel Derived Indium Oxide Films

Modification of sol-gel derived indium oxide thin films using ultraviolet lasers was investigated. Irradiation by an ArF excimer (6.4 eV) and the fourth harmonic generation of a Nd : YAG laser (4.7 eV) was found to be effective in crystallization with a loss of hydroxyl groups and a decrease in the sheet resistance of the sol-gel films. Transparent crystalline indium oxide films were successfully obtained by 6.4 eV laser irradiation at fluences below 20 mJ/(cm2·shot), whereas degradation of the films was induced by a relatively high-fluence beam.     

Determination of prostatic androgens in 10 mg of tissue using liquid chromatography–tandem mass spectrometry with charged derivatization

A practical liquid chromatography–tandem mass spectrometric (LC-MS-MS) method for the determination of prostatic 5-dihydrotestosterone (DHT) and testosterone (T) has been developed. The prostatic androgens were extracted with MeOH–H₂O (3: 7, v/v), purified with an Oasis HLB cartridge, derivatized with the permanently charged reagent 2-hydrazino-1-methylpyridine (HMP), and subjected to LC–MS-MS analysis using electrospray ionization (ESI) operated in the positive ion mode. The derivatization with HMP was very effective at increasing the detectability using the positive-ESI-MS. The method allowed the reproducible and accurate quantification of ng g^–1 tissue levels of prostatic androgens in 10 mg of tissue. That is, the intra- and inter-assay coefficients of variation were below 8.1 and 9.3%, respectively, and the analytical recoveries of the androgens were quantitative. The limits of quantitation for DHT and T were both 1.0 ng g^–1 tissue. The developed method was used to determine DHT and T in the prostates of patients with benign prostatic hyperplasia and prostate cancer, and satisfactory results were obtained.