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We use a regional chemistry transport model (Weather Research and Forecasting model coupled with chemistry, WRF-Chem) in conjunction with surface observations of tropospheric ozone and Ozone Monitoring Instrument (OMI) satellite retrievals of tropospheric column NO2 to evaluate processes controlling the regional distribution of tropospheric ozone over western Siberia for late spring and summer in 2011. This region hosts a range of anthropogenic and natural ozone precursor sources, and it serves as a gateway for near-surface transport of Eurasian pollution to the Arctic. However, there is a severe lack of in situ observations to constrain tropospheric ozone sources and sinks in the region. We show widespread negative bias in WRF-Chem tropospheric column NO2 when compared to OMI satellite observations from May–August, which is reduced when using ECLIPSE (Evaluating the Climate and Air Quality Impacts of Short-Lived Pollutants) v5a emissions (fractional mean bias (FMB) = −0.82 to −0.73) compared with the EDGAR (Emissions Database for Global Atmospheric Research)-HTAP (Hemispheric Transport of Air Pollution) v2.2 emissions data (FMB = −0.80 to −0.70). Despite the large negative bias, the spatial correlations between model and observed NO2 columns suggest that the spatial pattern of NOx sources in the region is well represented. Scaling transport and energy emissions in the ECLIPSE v5a inventory by a factor of 2 reduces column NO2 bias (FMB = −0.66 to −0.35), but with overestimates in some urban regions and little change to a persistent underestimate in background regions. Based on the scaled ECLIPSE v5a emissions, we assess the influence of the two dominant anthropogenic emission sectors (transport and energy) and vegetation fires on surface NOx and ozone over Siberia and the Russian Arctic. Our results suggest regional ozone is more sensitive to anthropogenic emissions, particularly from the transport sector, and the contribution from fire emissions maximises in June and is largely confined to latitudes south of 60∘ N. Ozone dry deposition fluxes from the model simulations show that the dominant ozone dry deposition sink in the region is to forest vegetation, averaging 8.0 Tg of ozone per month, peaking at 10.3 Tg of ozone deposition during June. The impact of fires on ozone dry deposition within the domain is small compared to anthropogenic emissions and is negligible north of 60∘ N. Overall, our results suggest that surface ozone in the region is controlled by an interplay between seasonality in atmospheric transport patterns, vegetation dry deposition, and a dominance of transport and energy sector emissions.

On the background of a high percentage of caries incidence, the prevalence of its complications is increasing – pulpitis, apical periodontitis. Teeth with complicated caries can cause odontogenic inflammatory processes in the maxillofacial region. Being foci of chronic infection and intoxication, they have an adverse effect on the body as a whole. In connection with the above, it is obvious that determining the optimal concentration of chlorhexidine bigluconate and exposure to the dentin of the crown part of the tooth in case of carious lesion of the latter is currently very important. The purpose of the study was to evaluate the antimicrobial activity of chlorhexidine (by suspension and contact method) in various concentrations in relation to monocultures of biofilm formed on tooth sections and in U-shaped 96-well plastic plates. Material and methods. In this work, one of the most relevant pathogens for modern medicine was Staphylococcus aureus, which was one of the most powerful pathogens that form biofilms, was used as a model. The antimicrobial activity of chlorhexidine bigluconate was evaluated on S. aureus and E. coli biofilm cultures formed on dental samples and in polystyrene plastic tablets. Antimicrobial activity was evaluated by the reduction factor was determined by the difference in the number of decimal logarithms of CFU/ml in the experiment compared to the control. The obtained data was subjected to statistical processing. Results and discussion. The study revealed that 2.0 % solution of chlorhexidine bigluconate had a high level of antibacterial activity against tablet biofilm cultures of S. aureus and E. coli. When it was exposed to S. aureus and E. coli tablet biofilm cultures with exposures of 30 and 60 seconds, statistically significant differences were found (p=0.02). Secondly, statistically significant differences in the effect of sensitivity of single-species biofilm cultures of dental samples to the effect of antiseptic at the specified concentration were determined (p=0.007). At the same time, the level of antibacterial activity of 2.0 % chlorhexidine bigluconate solution in respect of tablet biofilm cultures of S. aureus and E. coli was significantly higher than in biofilm cultures of S. aureus and E. coli of dental samples (p

The aim of this study is to determine the effects of structural soil restoration on the buffering capacities of these soils, their productivity, and the efficiency of their use as a basis for sustainable management. Based on a review of literature sources and our own experimental research, the proposed article shows the possibility of improving the buffering capacities of sod-podzolic cohesive sandy soils through the use of structural amelioration as an effective measure to protect them from degradation and ensure their resilience to climate change. The use of structural ameliorants (clay and peat) in the studied soils improves the granulometric composition, has a positive effect on the pH-buffering capacities, and contributes to optimizing the moisture capacity of soil. It was found that the efficiency of the application of structural amelioration on sod-podzolic cohesive sandy soils increases significantly with the local application method (e.g., clay in a dose of 10 t/ha or a combined application of clay in a dose of 2 t/ha with lowland peat in a dose of 3 t/ha). The largest yield increase in winter wheat (27.2%) was achieved by the local application of 2 t/ha of clay combined with peat in a dose of 3 t/ha.

Results obtained in the course of unique observations (as part of the TROICA project) of the composition and state of the atmosphere over Russia have been summarized. Scientists and engineers from different countries took part in these observations. The main task of these observations was to measure atmospheric contents of trace gases and aerosols and both meteorological and radiative characteristics of the atmosphere using a mobile laboratory designed and brought into operation specially for transcontinental observations along the network of Russian electrified railroads. A large database obtained in the TROICA experiments using the mobile laboratory, in field experiments, and at scientific stations is still under analysis. In this work, the most important results published earlier and obtained recently are discussed, which makes it possible to form a comprehensive picture of the spatial distribution and temporal variability of the atmospheric composition over northern Eurasia.

This paper presents the results of a comprehensive analysis of measurements of CO total content (CO TC) at stations of the Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences (IAP RAS), in Moscow and Moscow oblast. Also CO in-situ data obtained from automated stations of the Mosecomonitoring network, satellite monitoring results and information on the parameters of the atmospheric boundary layer in Moscow and the surrounding regions are analyzed. The long-term variability of CO TC and meteorological parameters is investigated, the carbon monoxide accumulation characteristics in calm days in the atmospheric boundary layer are obtained. A decrease in the average annual values ​​of TC CO in 2000–2018 was found in Moscow (–2.56 ± 0.52%/year) and at the Zvenigorod Scientific Station (ZSS) (‒1.15 ± 0.37%/year). However, the rate of decrease in both sites is different in different seasons and periods. After about 2007–2008, the rate of CO TC reduction decreased at both sites. In 2008–2018, at the ZSS, an increase in CO TC was recorded in the summer and autumn months at a rate of about 0.7%/year. An increase in the wind speed in the atmospheric boundary layer of Moscow in different periods of 2000–2018 at a rate of 0.4–1.6%/year has been determined. At the same time, no statistically significant changes in wind speed were found in Kaluga oblast. The recurrence of calm days in Moscow in 2006–2017 decreased (–7.06 ± 3.96%/year) with a decrease in the anthropogenic part of the CO content in the same period (–6.72 ± 3.48%/year). The results indicate the influence of the climatic (meteorological) factor on air quality in Moscow.

The high-voltage converter with the input voltage of 3000 V DC is considered for use as a power supply for auxiliary circuits of commuter electric trains and passenger cars that are used on Russian railways. The limitations on the use of semiconductor devices in converters with an input voltage of 3000 V are shown. The power electrical circuits of the input units of the considered high-voltage converters are shown when using of 1700 and 6500 V IGBT. The expressions for calculating the power losses and the algorithm for selecting the switching frequency of 6500 in IGBT are given. This article is of interest to developers of high-voltage DC converters with an input voltage of 3000 V and higher, which choose IGBT for the power circuit of input units with using the high frequency principle of the electrical energy transformation.

Исследования изменчивости спектральных биооптических показателей вод Атлантического сектора Антарктики проводили в 79-м рейсе НИС «Академик Мстислав Келдыш» в период с 11.01.2020 по 04.02.2020. Получено, что концентрация хлорофилла a в сумме с феопигментами изменялась в исследованном слое на большинстве станций от 0,1 до 1,8 мг·м−3, за исключением двух станций, где достигала 2,2 и 4,4 мг·м−3. Установлена связь показателей поглощения света пигментами фитопланктона с концентрацией хлорофилла a на длинах волн, соответствующих основным максимумам спектра: aph(438) = 0,044 × Ca1,2, r2 = 0,84 (n = 117); aph(678) = 0,021 × Ca1,1, r2 = 0,89 (n = 117). Спектры показателей поглощения света неживым взвешенным веществом и окрашенным растворённым органическим веществом описаны экспоненциальной зависимостью. Подобраны коэффициенты параметризации: (1) показатели поглощения света неживым взвешенным (0,001–0,027 м−1) и растворённым органическим веществом (0,016–0,19 м−1) на длине волны 438 нм; (2) коэффициенты наклона экспоненты спектров этих компонент (0,005–0,016 и 0,009–0,022 нм−1 соответственно).

The possibility of intraspecific typing the fungi of the genus Candida according to the spectrum of their sensitivity to antiseptics has been studied. The analysis of the maximum inhibitory dilution (MIR) of 16 antiseptics demonstrated the presence of both interspecies and intraspecific heterogeneity of clinical Candida isolates. The index of intraspecific heterogeneity of the studied species of the genus Candida in relation to various antiseptic agents, under experimental conditions, varied from 1 to 5. The maximum intraspecific heterogeneity of fungi was manifested in relation to the antiseptics Chlorhexidine bigluconate, hydrogen peroxide, combined antiseptics containing poly-ligexamethylene biguanidine ("Mukosanin" and "Septal"), "Hospisept Gel". According to the results of the study, an algorithm for intraspecific typing of Candida spp was proposed, based on an assessment of the phenotypic sensitivity of Candida to antiseptics. Typing of 20 clinical isolates of C.albicans was carried out. Comparative analysis of phenotypic sensitivity profiles to 4 different antiseptics made it possible to divide 20 clinical isolates of C. albicans into 12 variants, of which 6 isolates of C.albicans represented individual variants.

Based on the obtained kinetic regularities and the mixture of the products of the reaction of ethylbenzene oxidation with ozone in acetic acid, the scientific bases of the technology of synthesis of acetophenone was developed. It is shown that in the ozonation conditions, in the presence of manganese (II) acetate, it is possible to direct oxidation mainly through the ethyl group of the substrate with the formation of aromatic products. The technological parameters are studied and the optimal conditions for the process realization are ascertained. The obtained experimental and theoretical results allowed us to propose a new low-temperature low-waste method of acetophenone production, which ensures the efficiency of the process due to the mild oxidation conditions (288 K, atmospheric pressure) and the reduction of toxic waste. The technology can be an alternative to existing methods of the synthesis of aromatic ketones.

Short summary We summarize results during the last 5 years in the northern Eurasian region, especially from Russia, and introduce recent observations of the air quality in the urban environments in China. Although the scientific knowledge in these regions has increased, there are still gaps in our understanding of large-scale climate–Earth surface interactions and feedbacks. This arises from limitations in research infrastructures and integrative data analyses, hindering a comprehensive system analysis. The Pan-Eurasian Experiment (PEEX) Science Plan, released in 2015, addressed a need for a holistic system understanding and outlined the most urgent research needs for the rapidly changing Arctic-boreal region. Air quality in China, together with the long-range transport of atmospheric pollutants, was also indicated as one of the most crucial topics of the research agenda. These two geographical regions, the northern Eurasian Arctic-boreal region and China, especially the megacities in China, were identified as a “PEEX region”. It is also important to recognize that the PEEX geographical region is an area where science-based policy actions would have significant impacts on the global climate. This paper summarizes results obtained during the last 5 years in the northern Eurasian region, together with recent observations of the air quality in the urban environments in China, in the context of the PEEX programme. The main regions of interest are the Russian Arctic, northern Eurasian boreal forests (Siberia) and peatlands, and the megacities in China. We frame our analysis against research themes introduced in the PEEX Science Plan in 2015. We summarize recent progress towards an enhanced holistic understanding of the land–atmosphere–ocean systems feedbacks. We conclude that although the scientific knowledge in these regions has increased, the new results are in many cases insufficient, and there are still gaps in our understanding of large-scale climate–Earth surface interactions and feedbacks. This arises from limitations in research infrastructures, especially the lack of coordinated, continuous and comprehensive in situ observations of the study region as well as integrative data analyses, hindering a comprehensive system analysis. The fast-changing environment and ecosystem changes driven by climate change, socio-economic activities like the China Silk Road Initiative, and the global trends like urbanization further complicate such analyses. We recognize new topics with an increasing importance in the near future, especially “the enhancing biological sequestration capacity of greenhouse gases into forests and soils to mitigate climate change” and the “socio-economic development to tackle air quality issues”.

During 2020–2021, a comprehensive experiment was conducted to study the composition of near-surface atmospheric aerosol in Moscow. The paper considers the experimental data together with synoptic and meteorological conditions. Attention is focused on six episodes of extremely high aerosol mass concentration values: in March and October 2020, as well in March, April, May and July 2021. In all these cases (and only in them), the average daily mass concentration of PM10 aerosol exceeded the Maximum Permissible Concentration (MPC) value (according to Russian standards, 60 μg/m3). The origin of the aerosol during these periods of extreme pollution is revealed, which is the main result of the work. It was shown that the July episode of 2021 was associated with a local intensive anthropogenic source that arose as a result of the active dismantling and demolition of multistory industrial buildings. The remaining spring and autumn episodes were caused by atmospheric transport of both smoke aerosol from various regions with strong biomass fires and dust aerosol from arid zones of the south of European territory of Russia (ETR) with dust wind storms. The cases of atmospheric pollution transport to Moscow region from the other regions are confirmed with the help of air mass transport trajectories (HYSPLIT 4 model) and MERRA-2 reanalysis data on black carbon and/or dust distribution in the atmosphere over ETR. Differences in the elemental composition of the near-surface aerosol of Moscow air during periods with extremely high aerosol concentrations are analyzed in comparison with each other and with unperturbed conditions for the season.

This study considers usage of high-resolution data on CO and NO2 of newest orbital spectrometer TROPOMI.First, using our own software package Level 2 data (15 NetCdf files for every day) were converted to Level 3 (one daily mat-file) while maintaining spatial resolution. Then CO total content (CO TC) and NO2 tropospheric (NO2 TrC) and total content (NO2 TC) OFFL diurnal data were compared with OIAP ground-based measurements in Moscow and at Zvenigorod Scientific station (ZSS, Moscow province, 53 km West from Moscow) as well as with AIRS CO TC observations.The character of dependence between ground-based and satellite data was chosen as linear:Ugr = KUstl + A, were Ugr and Ustl are ground-based and satellite contents of an impurity, respectively; A is the constant.High correlation between TROPOMI CO OFFL and ground-based CO TC measurements was obtained, with R~ 0.79-0.85, K~0.78-0.91, A~2.3-5.0*1017 molec/cm2 in dependence on orbital data resolution.Correlation parameters depend on viewing azimuth angle VZA (the best correlation was obtained for VZA≤50º) and do not significantly depende on the Earth albedo.For diurnal NO2 TrC OFFL for ZSS were obtained R~ 0.41-0.48, K~3.3-4.3, A~0.9-1.1*1015 molec/cm2and for NO2 TC OFFL R~0.59-0.61, K~6.7-7.0, A~ (-)0.76-0.86 *1015 molec/cm2.Additional possibilities to calculate averaged spatial and trend distributions of different atmospheric species based on TROPOMI data using our original software are presented. The study was supported by Russian Science Foundation under grant №21-17-00210. NO2 data comparison was supported by the Russian Foundation for Basic Research, grant №20-05-00274.

Changes in the atmospheric composition in different periods of 2020 in Moscow, associated with the COVID-19 pandemic preventing measures of varying intensity and with corresponding reduction in emissions of pollutants, were investigated. Surface concentrations of nitrogen dioxide NO2, carbon monoxide CO, ozone O3, aerosol fraction PM10 and meteorological parameters in different periods of 2020 are compared with similar data for the previous 5 years. The analysis of ground-based measurements, as well as high-resolution satellite distributions of CO and NO2, indicated that the content of major pollutants and its spatial distribution in the Moscow region were significantly affected by both restrictive measures and abnormal meteorological conditions in 2020. It is possible to obtain quantitative estimates of the contribution of both factors using transport and chemical modeling based on detailed inventory of anthropogenic emissions.Additionally, some characteristics of atmospheric composition long-term trends in Moscow region are analyzed and discussed.The study was supported by Russian Science Foundation under grant №21-17-00210.

The results of an intensive complex experiment to study the composition and temporal variability of urban aerosol in near-surface air in the center of Moscow include daily data for two years on concentrations of PM10 and PM2.5 particles. In addition, in each season (for 35-40 days), measurements of the total aerosol mass concentration (by gravimetric method) and 65 chemical elements included in its composition are also carried out daily. For winter seasons, it is from January 10 to February 14, 2020 and 2021. Winter is the season with minimal aerosol pollution in Moscow. The total aerosol mass was 20.8 μg/m3 and 32.0 μg/m3 in the 2019-20 and 2020-21 seasons, respectively. Concentrations of all measured components in near-surface air did not exceed the MPC values for residential areas during both winters. However, the ratios of mass concentrations for particles PM2.5, PM10 and larger particles were different in these years. Mass ratios (in %) of aerosols of different sizes (10 μm) were 23:27:50 and 33:8:59 for 2020 and 2021, respectively. According to weather conditions, these two winters in Moscow were very different: the winter of 2019-2020 was abnormally warm with the shortest duration of snow cover for all the years of observations. On the contrary, the next winter of 2020-2021 was close to normal in terms of the main meteorological parameters, although the wind rose was characterized by an increased frequency of winds from the south. Studies have shown the leading role of meteorological conditions (in particular, humidity and air pressure), as well as long-range atmospheric transport in changing the level of aerosol pollution of near-surface air in Moscow. Analysis of the variability of the chemical element concentrations and enrichment factors (relative to the composition of the Earth's crust) identifies elements of predominantly anthropogenic (for example, Cd, Sb, Pb) or terrigenous (Co, Fe, Al, Cr), as well as global (S, P, B, Se, Bi) or local (Ca, Ni, W) origin. The results of winter observations of urban aerosol in Moscow are compared with the spring data of 2020 [1] and 2021. The work was financially supported of RFBR, grant No. 19-05-50088. [1] Gubanova, D.P., Vinogradova, A.A., Iordanskii, M.A., Skorokhod A.I. Time Variations in the Composition of Atmospheric Aerosol in Moscow in Spring 2020. , Atmospheric and Oceanic Physics. 2021. V. 57, No. 3. P. 297–309. https://doi.org/10.1134/S0001433821030051