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Researchers are currently paying more and more attention to the combined pathology of the tooth pulp and periodontal. At the same time, the peculiarities of the structure of the alveolar bone, the cement of the tooth root and the root canal system that cause their interrelation and mutual influence remain insufficiently studied. The main elements of the connection between the pulp and periodontal tissues are not only apical openings and additional channels, but also other ways of interaction, the study of which is of great interest for understanding the features of pathogenesis, prognosis and treatment of combined diseases of the tooth pulp and periodontal. The aim of the study is to identify the topographical and anatomical features of the structure of the roots of teeth of different functional groups and the surfaces of their holes when studying on human cadaver material. The hypothesis of the study is that the number of openings of the Haversov channels and their localization in the moons are due to the functional affiliation of the teeth and they have their own characteristics. Material and methods. The study was conducted on jawbones with teeth obtained from embalmed corpses of adults of different genders and ages. After appropriate preparation, at the first stage, microscopy of the alveolar surfaces was performed, followed by morphometric analysis of the photos. At the second stage, scanning electron microscopy (SEM) of the surfaces of the roots of teeth previously extracted from the same wells of the jaws was performed. Results and discussion. All the preparations were systematized according to the number and topography of the identified holes of the Haversov channels. Because of the assessment of morphometric indicators, the number of holes, the density of their location and the diameter were determined, depending on the functional affiliation of the teeth. The analysis of microphotographs obtained because of SEM allowed us to determine the structural features of the surfaces of the roots of the teeth. Conclusions. The number, density and diameter of the holes of the Haversov channels are determined by the functional affiliation of the tooth. With the help of SEM, micro cracks and areas of root dentin exposure were found on the surfaces of the roots of the teeth for the first time, which can contribute to the translocation of pathogenic microbiota from the periodontal pocket to the pulp of the tooth and vice versa.

The effect of temporary radioactive waste storage on the ecological status of the sea and biota in the littoral of Andreev and Malaya Andreev bays and near the shore of Motovskii Gulf (including the mouth part of the Zapadnaya Litsa Bay) was analyzed. The littoral sediments contaminated by the 137Сs, 90Sr, 238Pu, and 239,240Pu isotopes are located in the zones of constant groundwater discharge on the shores of Andreev and Malaya Andreev bays. The littoral slopes and bottom depressions of the bays accumulate finely dispersed terrigenous material and 137Сs. The investigations have shown that the storage does not exert a significant adverse effect on the radioactive conditions and the status of the sea ecosystems beyond Andreev Bay.

The polar cod (Boreogadus saida) has a circumpolar distribution and is the most abundant planktivorous fish in the Arctic. Declining sea-ice coverage impacts polar cod directly and also facilitates expansion of human activities in the region leading to increasing anthropogenic pressures on biota. Here we summarize current data and knowledge on polar cod from the Russian sector of the Barents Sea and discuss knowledge needs for the management of polar cod under changing environmental conditions and anthropogenic impacts. We review 36 Russian historical (1935 - 2020) sources of data and knowledge largely unknown to western researchers, in addition to sources already published in the English language. This effort allowed for digitalization and visualization of 69 separate datasets on polar cod ecology, including maturation, fertility, feeding intensity, diet, lipid content, length-weight relationships and seasonal variation in larval size. Our review suggests that polar cod abundances are particularly large in the eastern Barents Sea and adjacent waters. Here, we identify and discuss key knowledge gaps. The review of polar cod in the eastern Barents Sea revealed 1) major variation in the timing and area of polar cod spawning, 2) uncertainty as to what degree the polar cod is dependent on sea ice, 3) deficient knowledge of juvenile (e.g., 0-group) distributions, particularly in the north-eastern Barents Sea, 4) deficient knowledge of the species' genetic structure and spatio-temporal distributions, and 5) insufficient understanding as to whether ongoing environmental change may induce phenological changes affecting the availability of potential food items for polar cod larvae and their match in space and time. Filling these knowledge gaps would provide an important step towards the reliable knowledge base needed in order to perform well-founded management and impact assessment under environmental changes and increasing anthropogenic impacts.

Arctic marine ecosystems are a very sensitive indicator of global climate change. Their reaction to climate anomalies predetermine the bioresource potential of the Arctic seas and the ecological safety of marine activities in the zone of the Northern Sea Route. This article, based on a paper presented at the RAS Presidium meeting on May 24, 2016, evaluates the current natural processes in the Arctic from the point of view of the theory of large marine ecosystems, which are viewed as the entirety of the marine environment and biota taking into account the totality of external climate and anthropogenic effects. The necessity of technical modernization and optimization of integrated monitoring of such ecosystems is noted, including their biological, ecological, and socioeconomic components.

Taking into account the interrelated vibration dynamics of cutting and the temperature in the cutting zone allows you to determine the most successful state or cutting mode in terms of energy costs. Purpose of the work: by forming a consistent model, determine the most convenient mechanism for the mode of operation of the cutting system, in which the further wear of the cutting wedge will be stabilized, the cutting force will also be stabilized, as well as the temperature in the cutting zone and the vibration of the tool. The paper examines: The process of metal processing by cutting on a lathe for the case of longitudinal turning of the product. Research methods: The research consists of a series of field experiments on real equipment using a modern measuring stand STD. 201-1, as well as using an experimental complex developed by us. Results and discussion. The results of processing experimental data, in particular, the results of measuring cutting forces, temperature and tool vibrations, are presented. The mechanism of stabilization of the processing process due to the relationship between temperature and vibrations during cutting and the formation of a quasi-stationary cutting mode is experimentally proved. It is assumed that due to the practical application of the results obtained in the work, it will be possible to increase the energy efficiency of metal processing by reducing the energy cost of vibration of the cutting wedge.

As practice of using and edge tool in metal-cutting units, wear progression during cutting leads to changes of generated forces. The present work presents the possibility of diagnosing the tool wear degree based on results of monitoring the cutting force components. The paper is founded on the high-scale examination of experiments carried out on the advanced equipment with plotting characteristic curves in Matlab. Analysis of experimental data enabled to deeply imagine how wear of an edge tool affects cutting forces during metal working. Eventually, the paper proposes the new method for diagnosing critical wear of the tool based on evaluation of the force component that inhibits shape-generating movements in the axial feed direction (it is found out herein that this component is the most meaningful one). Using this approach simplifies the existing diagnosing systems and allows for evaluating the wear degree based on the engine input current that provides for tool feed when cutting.

In paper the developing of geoinformation technology for estimation of Atlantic-origin waters inflow and polar front parameters is presented. It is based on common issues, best practices, modern theoretical studies, heuristics and software development tools applied to research in the Barents Sea. Main hydrographic datasets are long-term in situ measurements values stored in World Ocean Database and in database of Murmansk Marine Biological Institute. Spatial distribution is investigated in details in the areas of Kola Transect. Some results concerning seasonal and inter-annual variability of salinity are described and prospects of research are formulated.

Present climatic trends in the Barents Sea and Kara Sea Large Marine Ecosystems are estimated using Russian observational data and external information sources. It is shown that a warming period which reached its maximum in the beginning of the 21st Century was replaced by a cooling trend of water masses and a decrease in ice covered area. Regularities of large warm anomalies formation in the Arctic were accompanied by a strong cold event in Southern Europe.

This paper analyses the anomalous hydrometeorological situation that occurred at the beginning of 2012 in the seas of the Russian Arctic and Russian South. Atmospheric blocking in the temperate zone and the extension of the Siberian High to the Iberian Peninsula (known as the Voeikov et al. axis) led to a positive anomaly of air and water temperatures and a decrease in the ice extent in the Barents and Kara Seas. At the same time a prolonged negative air temperature anomaly was recorded in central and southern Europe and led to anomalously severe ice conditions in the Sea of Azov. Winter hydrographic conditions in the Barents and Kara Seas are illustrated by a unique set of observations made using expendable bathythermosalinographs (XCTD).

The Barents Sea is a transition zone between North Atlantic and Arctic waters, so its marine ecosystem is highly sensitive to climate dynamics. Understanding of marine biota response to climate changes is necessary to assess the environmental stability and the state of marketable biological resources. These processes are analyzed using a database from the Murmansk Marine Biological Institute which holds oceanographic and hydrobiological data sets collected for more than 100 years along the meridional Kola Transect in the Barents Sea. The data demonstrate high variability in thermal state of the upper layer of the Barents Sea, which is regulated by varying the inflow of Atlantic water and by regional climate. At irregular intervals, cold periods with extended seasonal ice cover are followed by warm periods. The most recent warm period started in the late 1980s and reached its maximum from 2001 to 2006. These cyclic changes in hydrologic regime across the twentieth century and first decade of the twenty-first century are reflected (with a specific lag of 1–5 years) by changes in species composition, as well as abundance and distribution of boreal and arctic groups of macrozoobenthos and fish fauna. For instance, cod and cod fisheries in the Barents Sea are closely linked to the marine climate. Furthermore, Kamchatka crab stock recruitment benefited from the warm climate of 1989 and 1990. In general, studies in this region have shown that climatic dynamics may be assessed using biological indices of abundance, biomass, and migration of marine organisms, including commercial species.

Based on the results of multiannual oceanographic research at the Murmansk Marine Biological Institute in the “Kola Meridian” secular section, the recent tendencies of cyclic climate changes in the Barents Sea are discussed on the basis of the data on ice coverage and coastal meteorological conditions. It has been shown that a return from the extremely warm and warm state to the normal one was observed in the period of winter 2005/06–winter 2010/11. Further, this may be changed both to cooling and warming, which verifies the hypothesis about predominance of cyclic natural variability in the thermal and ice characteristics of the Arctic Region.

This paper discusses the role of glacial shelf topography in the formation of general oceanological and biological mechanisms in the Barents Sea. Analysis of geomorphological data and oceanographic observations obtained on board MMBI research vessels in 2001-08 has shown that: fluxes of Atlantic-origin waters pass along glacial troughs; the inflow of Atlantic waters to the Barents Sea from the west increased from 2001 till 2007, although this advection began to weaken in 2008; vertical and horizontal thermohaline gradients intensified during the investigated period; a warm period similar to that of the 1930s was observed in the Barents Sea at the beginning of the 21st century.

Connectivity between the terrestrial and marine environment in the Artic is changing as a result of climate change, influencing both freshwater budgets and the supply of carbon to the sea. This study characterizes the optical properties of dissolved organic matter (DOM) within the Lena Delta region and evaluates the behavior of DOM across the fresh water-marine gradient. Six fluorescent components (four humic-like; one marine humic-like; one protein-like) were identified by Parallel Factor Analysis (PARAFAC) with a clear dominance of allochthonous humic-like signals. Colored DOM (CDOM) and dissolved organic carbon (DOC) were highly correlated and had their distribution coupled with hydrographical conditions. Higher DOM concentration and degree of humification were associated with the low salinity waters of the Lena River. Values decreased towards the higher salinity Laptev Sea shelf waters. Results demonstrate different responses of DOM mixing in relation to the vertical structure of the water column, as reflecting the hydrographical dynamics in the region. Two mixing curves for DOM were apparent. In surface waters above the pycnocline there was a sharper decrease in DOM concentration in relation to salinity indicating removal. In the bottom water layer the DOM decrease within salinity was less. We propose there is a removal of DOM occurring primarily at the surface layer, which is likely driven by photodegradation and flocculation.

A model for solving the problem of heat distribution along the front surface of a tool with a shaped profile is considered. Analytical dependencies for estimating the temperature of the tool of elliptic profile for turning with radial feed in Cartesian and polar coordinate systems are obtained for the model under consideration. As a result, the obtained dependences can be applied to similar thermal calculations of instruments with other forms of plane curves both in turning with radial feed and in milling conditions. The calculation of a flat temperature field on the front surface of a shaped tool has been carried out and it has revealed areas with the highest temperatures at the contact area and the maximum wear values.