Vol 23, No 5 (2016)

The goal of the research is to find out the main low-intensity radioactive anomalies as the main probable source of human light irradiation in Arkhangelsk city; give an objective estimation of radiation risks and potential health damage of the local population. Avtogamma-spectrometric method, using a mobile radiation monitoring system RS-700 was firstly used in the city. It allows to measure both natural and artificial radionuclides in real time geo-referenced. Ground gamma survey method with geological prospecting scintillation radiometer SRP-88H has been used for specification of obtained results. Soil sampling has been selected in each city block with further definition of radionuclides specific activity in the gamma spectrometer counting sample "Progress". A unique set of data on the radioactive level and the specific activity of 137Cs, 40K, 232Th, 226Ra in the soil have been collected as a part of the radio-ecological study. Nine local low-intensity anomalies have been revealed and their genesis has been set. The comparative comprehensive assessment of low doses ionizing radiation on human health has been done. Possible ways of further medical and environmental research in the field of oncological diseases and radioactivity study in the city of Arkhangelsk have been planned.

The article presents the results of workplaces certification on the Joint-Stock Company "Diversified manufacturing company "KRZ" according to working conditions. The company deals with computer-aided production of rolled- roofing materials. Content of chemical substances and aerosols of fibrogenic action in the air of working zones, as well as industrial noise levels, artificial light, microclimate, workflow severity and intensity in the shops of rolled-roofing and waterproofing materials and paper and paperboard production of the enterprise have been estimated. According to the results of hygienic investigation most of working environment was harmful (class 3 1-2 degrees). Workers of major technical professions such as operators of dipping units, turbomixers operators, bitumen unwatering operators, papermaking sorters, cardboard machine (CBM) operators, CBM couchers, CBM machinists, CBM drying operators were exposed to a complex of environment factors, the most unfavorable of which are chemical, microclimate and severity of labor process. Our recommendations for improving working conditions are to introduce technological measures: mechanization of beating-engines and thickeners cleaning, talcose emulsification, modernization of winding and wet-tissue packaging machines. Space-planning decision is isolation of automated production lines for rolled roofing material. The plan for sanitary-hygienic measures includes hoods installation on the dry end of the production line, use of the hydrodedusting system, equipment of local artificial lighting according to the workplace sanitary standards, organization of work and rest schedule with double shift work and two weekends. As mandatory respiratory protective equipment - respirators SHB-1 "Lepestok™-5" are recommended; organs of vision protective equipment - goggles; skin - hand protection water-repellant cream, hand cleansing paste, silicone hand cream; work clothing - bitumen protection cotton suit with coated fabric laps; canvas gloves.

Features of CNS development have been investigated in children and adolescents living under the severe ecological conditions in the North of Russia. The original method for estimating a time structure of the EEG frequency components interrelations was used to study the dynamics of maturation of bioelectrical brain activity pattern and age-related changes of the interplay between the main EEG rhythms. It was found that the statistical structure of the interaction of the frequency components of EEG is undergoing a significant restructuring with age and has certain topography and gender differences. The period from 7 to 18 years of age is marked by decrease the probability of interaction of wave components of the main EEG frequency bands with components of delta and theta bands while simultaneously increasing interaction with the components of beta and alpha2 frequency bands. The dynamics of studied indices EEG manifested in the parietal, temporal and occipital regions of the cerebral cortex to the greatest extent. The largest sex-related differences in the EEG parameters occur in puberty. Functional core of the wave components interaction that maintain the structure of the frequency-temporal EEG pattern is formed to 16-18 years in girls in alpha2-beta1 range, while in boys - in alpha1-alpha2 range. Intensity of age-related rearrangements of the EEG pattern reflects the gradual maturation of electrogenesis in different brain structures and has individual features due to both genetic and environmental factors. Obtained quantitative indicators of formation with age of dynamic relationships between basic EEG rhythms permit to reveal children with disturbed or delayed development of the central nervous system.

This article presents propensity score matching (PSM) - modern statistical method to control for confounding, which threatens the validity of associations in observational studies. The efficiency of PSM has been demonstrated in several international studies. The increasing use of PSM by the research community is reflected by steady growth of the number of publications with this method in the PubMed database over time. This article presents the theoretical basis of PSM and its practical application using Stata software. In the practical part of the article, detailed step by step algorithms of various PSM methods are presented allowing researchers to conduct statistical analysis of their own data and interpret results.