Proceedings of the Estonian Academy of Sciences

CONTENTS & ABSTRACTS

In English. Summaries in Estonian

Proceedings of the Estonian Academy of Sciences.

Chemistry

Volume 49 No. 4 December 2000

Formation of chemical nomenclature and terminology in the Estonian language; 187–206

Hergi KARIK

Abstract. A review of the development of chemical nomenclature and terminology in the Estonian language since 1869 is presented. The use of the names of chemical elements and compounds in scientific publications and the language of chemistry textbooks is compared. The work of the Estonian Commission on the nomenclature of chemistry and adaption and translation of international rules into the mother tongue according to IUPAC’s recommendations is discussed. In Estonian, summary in English.

Key words: chemical nomenclature and terminology, Estonian language, history of Estonian chemical nomenclature and terminology, Estonian dictionaries of chemistry.

Characterization of capillary electropherogram profiles of meat extracts by entropy; 207–215

Sirli SIPP, Mihkel KOEL, and Mihkel KALJURAND

Abstract. Meat samples from a local supermarket were subjected to various sample preparation procedures and later analysed using several capillary electrophoresis separation conditions varying buffer pH and additives. Shannon’s entropy function was used for quantitative estimation of the complexity and structural richness of the pherograms of the meat extracts, aiming to find out the optimal sample preparation and analysis protocol for meat species identification by capillary electrophoresis. Modification with ethylene glycol decreases the entropy value of pherograms, offering more characteristic patterns than methods where only the pH value of the buffer is altered. Entropy is minimal for pherograms of capillary gel electrophoresis with linear, non-cross-linked gel, showing suitability of this method for profiling different meat extracts.

Key words: meat analysis, capillary electrophoresis, Shannon’s entropy.

Influence of extracellular magnesium on the antitumour efficiency of photodynamic therapy; 216–233

Vladimir CHEKULAYEV, Igor SHEVCHUK, Lyudmila CHEKULAYEVA, and Raissa JÄÄLAID

Abstract. This study was designed to evaluate the influence of extracellular Mg on the antitumour efficiency of haematoporphyrin derivative (HpD)- or chlorin-e₆ trimethyl ester (E6)-based photodynamic therapy (PDT). In vitro experiments showed that in a calcium/serum-free medium the addition of MgCl₂ (from 1 up to 5 mM) to Ehrlich ascites carcinoma (EAC) cells induced (as measured by trypan blue test) a 1.5-fold increase in HpD–PDT efficacy. Moreover, during the HpD–PDT the presence of MgCl₂ enhanced the inhibition of both glycolytic and dehydrogenase activity of EAC cells, stimulated the photo-oxidation of cellular proteins and lipids, which was associated with a more considerable decrease in the reduced glutathione content. In the experimental conditions, Mg itself was practically nontoxic towards the cells at all concentrations investigated. Nevertheless, at a physiological concentration (1 mM) of Mg²⁺, only a weak (about 10%) increase in the rate of HpD-photosensitized inactivation of EAC cells was observed. The influence of extracellular Mg on the efficiency of PDT did not depend on the nature of the sensitizer used; the in vitro effects with E6 were similar to those seen for HpD. However, in contrast to the in vitro experiments it was found that in vivo an elevated level of extracellular Mg increased essentially the viability of EAC cells pretreated (before intraperitoneal inoculation) with HpD–PDT. Although the exact molecular mechanisms are largely unknown, the in vivo results suggest that Mg is, most probably, a serum factor decreasing the antitumour efficiency of HpD–PDT.

Key words: haematoporphyrin derivative, chlorin-e_6, photodynamic therapy, tumour, magnesium.

Two-phase ozonation process for the destruction of phenolic pollutants; 234–239

Guido RAJALO, Tamila PETROVSKAYA, and Maya GLUSHKO

Abstract. A liquid–liquid ozonation technique was applied for the destruction of phenol, 4-methyl-phenol, and 4-chlorophenol from aqueous solution. The ozonation process was carried out in a reactor–absorber system with a circulating ozone carrier. Simultaneously with the oxidation of phenol in the reactor the saturation of the carrier by ozone in the absorber occurred. The two-phase ozonation of phenolic compounds is a mass transfer process accompanied by a surface reaction. The overall process rate is increasing in the order phenol–4-chlorophenol–4-methylphenol.

Key words: ozonation, fluorinated solvent, waste water, phenol, 4-methylphenol, 4-chlorophenol.

Comparative calculations of molecular vibrations of some acetylenic compounds; 240–243

Sirje MÄEORG, Peeter BURK, and Uno MÄEORG

Abstract. Normal mode vibrational frequencies of 24 acetylenic hydrocarbons and alcohols were calculated by using MM3, MMFF94, and PM3 methods. The results were compared with experimental data. The best method for the estimation of the frequencies of the stretching vibrations related to the CC triple bond was MM3, which had the relative rms error of 0.3–0.7%.

Key words: molecular vibrations, acetylenic compounds, MM3, MMFF94, PM3.