Transformation of the radionuclides composition of river sediments in the area of the exploited Lomonosov diamond deposit (NW Russia).

The article is devoted to the study of the activity of the natural radionuclides 40K, 232Th, 226Ra and technogenic 137Cs radionuclide in the river sediments of watercourses around the Lomonosov diamond deposit (northwestern Russia). This is the only large diamond mining and beneficiation complex in Europe. Samples of river sediments and surface waters were taken from the Zolotitsa River and its tributaries in the area of the diamond deposit. Samples of rocks were taken from quarries. Samples of kimberlites used for enrichment and rocks entering the dumps were selected. Measurements of the activity of radionuclides in bottom sediments and rocks were conducted using the low-background semiconductor gamma spectrometry method. For measurements, a detector from high-purity germanium was used. The study of uranium isotopes in bottom sediments and waters was conducted using the alpha spectrometry method. The average activity of 137Cs, 226Ra, 232Th and 40K were 5.4, 9.0, 11.2, 318.8 Bq·kg-1 respectively. The impact of the development of the field on the change in the radioecological state of the bottom sediments was evaluated. Several patterns of radionuclide accumulation have been found depending on the physicochemical parameters of river sediments. These patterns are due to the technogenic influence of the mining and beneficiation complex. The performed studies present the first evaluation of the impact of diamond mining on natural radionuclides' distribution and accumulation in the river sediments within the adjacent territories.

Influence of climatic and hydrological factors on structure and composition of peat from northern wetland territories with low anthropogenic impact.

Northern wetlands ecosystems play an important role in the hydrological balance of neighboring areas, where they act as chemical barriers against anthropogenic and technogenic contaminations. Studied region is well known for quantity of peat deposits and the volume of peat resources. Peat can be considered as a highly informative marker for assessing change in environmental conditions. The study presents the results of the first investigation of peat samples, collected from representative ecosystems of northern wetland territories with low anthropogenic impact. Component and element composition of various peat types were studied in a relation to hydrologic, climate and sampling conditions. It was found out that organic and ash contents are more dependent on the type of the bog, than geographic location. Climatic factors are more important for the formation of bitumen. The degradation degree in peat increases proportionally to content of humates. High content of biogenic and lithogenic elements was observed in transition- and low-moor peat. The content of trace elements in peat samples do not depend on the type of the peat. The structural properties of peat were studied by the light microscopy, AFM and dynamic light scattering. It was determined that the conformation of studied peat samples is characterized by elements of asymmetry. The observed particles in the solutions exist in dynamic equilibrium with separated globular macromolecules. The size of these nanoparticles is comparable with the size of the particles of other biopolymers of similar nature. Swelling of peat in liquid water was studied. The relationship between structural specificities, origin of peat and its maximum degree of swelling was found. The degree of swelling can be used as structural-sensitive parameter in further research.

[Determination of oxygen saturation of circulating blood from pulse wave amplitude]. / Opredelenie stepeni nasyshcheniia tsirkuliruiushchei krovi kislorodom po amplitude pul'sovoi volny.

The oxygen saturation of circulating blood (SaO2) can be determined from the modulation depth of luminous flux passing through the tissue filled with pulsing blood. For calculation of SaO2, an equation has been derived from the output signal amplitude of the current-voltage transducer.

[Selective activation of DNA biosynthesis in rat kidneys following ethyleneimine administration]. / Izbiratel'naia aktivatsiia biosinteza DNK v pochkakh krys pod vliianiem étilenimina.

Selective activation of RNA and DNA synthesis in response to ethylene imine accompanied by subsequent corresponding increase in amount of the nucleic acids, was found in rat kidney. Maximal efficiency of ethylene imine was manifested after administration of non-lethal doses 2.4 mg/kg; lethal doses of the poison were not effective. The alterations were characteristic for both young and adult animals. Similar phenomenon was not detected either in tissues with rapid renewal of cells (thymus, spleen) or in other tissues (liver, lungs).