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- Author or Editor: M. Novák x
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Abstract
A simple, sensitive and reliable method was developed for the determintion of hydrazine in technological waters of NPPs. A pulverized mixture of oxalic acid and p-dimethylaminobenzal dehyde is added to a sample. As low as 1.5 
g.dm–3 hydrazine can be determined. The method is dependent of the sample temperature. The agent is stable, readily soluble in water, and not hygroscopic.
Abstract
A short overview of HPLC column packings is presented. The properties of chromatographic carriers and the possibilities to combine the solid matrices with organic polymeric stationary phases are elucidated in detail. The latest achievements and anticipated future developments in the area are outlined.
Solid inclusion complexes of TolperisoneHCl with five various cyclodextrins were prepared by kneading and spray drying. The complex formation between the drug and the cyclodextrins were proven using thermoanalytical methods, X-ray diffraction, IR spectroscopy. The results of the solid state investigations were supported by the liquid phase investigations, such solubility and parition constant measurements and stability constant determination. Among all cyclodextrins used the β- and γ-CD-s were found to be the best complexing agents.
Abstract
Differential scanning calorimetry (DSC) is applicable to studying the thermal properties of bacteria when treated with heat, cold, or antibiotics. Foodborne pathogens are inactivated by heat, and denaturation transitions observed by DSC indicate potential sites of cellular injury. Ribosomes, which are the sites for messenger RNA translation, are one critical component of thermal damage as evidenced by characteristic denaturation transitions in the 66-74C range. These transitions disappear when cells of Clostridium perfringens are subjected to heat, suggesting structural or conformational changes to ribosomal proteins, and when cells of Listeria monocytogenes are cold-shocked by refrigeration, indicating ribosomal dissociation. DSC can be used to show that refrigeration followed by heat treatment improves the killing of dangerous microorganisms.
Mutant soybean germplasm was developed from a Carpathian-Ukrainian local variety, using 100–300 Gy chronic gamma irradiation to obtain lines with improved oil and/or protein content. The mutant germplasm was developed by the pedigree method. Selection for high oil and protein content started in the M3 generation. Plants with 24.1 and 23.6% oil content in the seeds were detected in the M4 generation. There were negative, moderate (r = –0.4) and significant (P<0.1 and P<0.01) correlations between the oil content and the 1000-seed weight in both the M3 and M4 generations. The fatty acid composition in the seeds of plants with high oil content was favourable. It is suggested that selection for oil content in the seeds should be started in the M4 generation. Due to the limited genetic variation for protein content no mutant genotypes with higher protein content than that of the control could be identified.
Abstract
A rapid method for the determination of uranium at nanogram levels in geological and biological materials is described. The method is based on the separation of 23.5 min239U, produced on neutron activation, by solvent extraction with TBP from nitric acid medium in the presence of HF, which prevents interference from Th; a number of other possibly interfering elements were shown to be negligibly extracted. The method is selective and sensitive enough for the determination of nanogram levels of uranium in soils, ores and biological samples. Results for some standard reference materials were in good agreement with certified values.
Non-conventional geoelectric arrays — Results of the OTKA project K49604
Theoretical basis
In frames of a Hungarian Scientific Research Fund (OTKA) project (No. K49604), we systematically investigated all published surface geoelectric arrays, since a part of them are out of use, even completely forgotten. Even in case of these latter ones we were optimistic in their potential renaissance, due to the rapid advance in geophysical knowledge and technical development. Therefore at first we collected all surface geophysical arrays, ever used in geophysical exploration. We presented all of them in a standard way, and we classified them. This collection proved to be the basis of still on-going inter-comparisons. We revealed the original motivation of their design, as well. Then we produced parameter sensitivity maps for all possible arrays, by using a new analytical approach. Parameter sensitivity maps for non-linear and focussed arrays had never been presented before. Through examples (mainly for null-arrays, one of the focal points of our project) we presented, how these maps can be applied. Then another characterizing parameter, the depth of investigation was studied. The so-called depth of investigation characteristics (DIC) was computed for all the 30 arrays, where it exists, both in terms of Roy and Apparao (1971) and Edwards (1977). We carried out various comparisons, and revealed a complex relation among vertical resolution, depth of investigation and noise. We showed how the depth of investigation is constrained by the noise level. Therefore the maximal (theoretical) depths of investigation for 6 arrays were studied at various noise levels. Besides some further theoretical studies, our further work will concentrate on measurements. The general characterization of so many geoelectric arrays provides a better knowledge about them, and it will be hopefully useful also for other teams to select always the optimal arrays in their field problem. It should be mentioned, that this paper does not contain mathematical details. If the reader would like to reproduce the results demonstrated on the figures, the referred previous publications of the authors should be studied.
A new unstable organ-specific Adh1 mutant was isolated from autotetraploid S 25 Wf9 maize line after germinating kernels under water for two days. Adh1-Fm4x-1 expresses normal and/or reduced levels of ADH1 in anaerobic scutellum. No activity or approximately 33–75% of wild type level of ADH1 in pollen grains was observed. The organ-specific phenotype of the Adh1-Fm4x-1 could be maintained by selfing for ten subsequent generations. After crossing with the wild-type allele the Adh1 mutation transmitted to the next generation both by female and male gametophytes. The appearance of one- and two-banded patterns in anaerobic scutellum and pollen grains of heterozygous F 1 plants showed the lack of F·F homodimers.DNA sequence analyses of the wild type allele, the Adh1-Fm4x-1 mutant allele and four F 1 revertants revealed that the Adh1-Fm4x-1 mutation contains a Dissociation (Ds1) transposable element in the 5′ untranslated leader of the maize Adh1 gene, which regulates organ-specific expression at a quantitative level.
