Chromosome damage and the spectrum of aberrations induced by low doses of gamma-irradiation, X-rays and accelerated carbon ions (195 MeV/u, LET 16.6 keV/microm) in peripheral blood lymphocytes of four donors were studied. G0-lymphocytes were exposed to 1-100 cGy, stimulated by PHA, and analyzed for chromosome aberrations at 48 h post-irradiation by the metaphase method. A complex nonlinear dose-effect dependence was observed over the range of 1 to 50 cGy. At 1-7 cGy, the cells showed the highest radiosensitivity per unit dose (hypersensitivity, HRS), which was mainly due to chromatid-type aberration. According to the classical theory of aberration formation, chromatid-type aberrations should not be induced by irradiation of unstimulated lymphocytes. With increasing dose, the frequency of aberrations decreased significantly, and in some cases it even reached the control level. At above 50 cGy the dose-effect curves became linear. In this dose range, the frequency of chromatid aberrations remained at a low constant level, while the chromosome-type aberrations increased linearly with dose. The high yield of chromatid-type aberrations observed in our experiments at low doses confirms the idea that the molecular mechanisms which underlie the HRS phenotype may differ from the classical mechanisms of radiation-induced aberration formation. The data presented, as well as recent literature data on bystander effects and genetic instability expressed as chromatid-type aberrations on a chromosomal level, are discussed with respect to possible common mechanisms underlying all low-dose phenomena.

The article summarizes the natural increase / decrease in the population of the regions and macroregions of the Russian Federation for 1992-2019. Depopulation is a steady natural population decline, it's characteristic of most European territories (countries or parts thereof), whose population was heavily affected in World War II. This applies to both sides of the conflict — and fascist Germany (as well as militaristic Asian Japan), on the one hand; and the territories of modern Poland, the Republic of Belarus, Ukraine, the European part of the Russian Federation, parts of the former Yugoslavia, on the other hand. As a result, since the 1970s the population of these territories began to enter a period of depopulation, the excess of mortality over fertility. This happened as a result of a downward demographic wave, the so-called «first echo of the Second World War», as well as due to global trends of declining birth rates in the entire developed and rapidly developing world. In general, over the 28 years of the post-Soviet period from the beginning of 1992 to the beginning of2020, depopulation covered all European regions of Russia with the exception of 5 republics of the North Caucasus and the Republic of Kalmykia. A somewhat different picture was observed beyond the Ural Range. Here, the depopulation in most large industrial regions was primarily due to the post-Soviet migration outflow of the population to the European part of the country — to the capital regions and plains of Southern Russia with a favorable climate. Positive natural growth was only in the oil and gas bearing Tyumen oblast, the Republic of Yakutia (Sakha), Chukotka Autonomous Okrug, as well as in the republics of Southern Siberia, whose indigenous population professes Buddhism. The article presents an analysis for each of the typical groups of Russian regions, provides statistics for 28 years of the demographic (reproductive) development of territories, substantiates conclusions, among which the main one is the following. The decrease in the volume of current and upcoming demographic human losses in Russia depends on the consistency, scientific justification, efficiency, effectiveness and selectivity of the country's demographic policy.

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The article shows how political, economic, environmental and other events, phenomena and processes (external factors) lead to sharp changes in the age structure of the population of the regions of Russia, creating structural waves, that is, steep changes in population by age. It is revealed how various components of the demographic balance (internal factors) in dynamics affect the perturbation and smoothing of age-related structural waves. Taking into account the experience of previous studies and on the basis of a large array of empirical data, the use of two generalizing meters of demographic structural waves of the regions of the Russian Federation is justified. The first indicator is the coefficient of unevenness of th7e age structure of the population regarding the structure of the calculated series of "Numbers living in a given age interval". The second indicator is a combination of two coefficients of structural differences (shifts) used in practice, A. Szalai and K. Gatev. The results of a comparative analysis of structural demographic waves in all regions of Russia for the last year before the start of the pandemic in 2019 are reflected. All regions of Russia are ranked according to the proposed coefficients of unevenness. Fourmain groups of territories have been identified from the regions according to the degree of unevenness of the age structure of the population. The main factors that caused this unevenness are revealed. The task of smoothing the structural demographic waves in the young population (0-45 years old) by building and implementing a time-emphasized and regionally accentuated concept of demographic policy in the field of fertility, interregional and international migration has been substantiated. This concept should be coordinated with the strategy of Russia's demographic development.