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The qualitative composition of lipophilic secondary metabolites in the medicinal plant leuzea safflower ( Rhaponticum carthamoides (Willd.) Iljin) has been studied by gas chromatography - mass spectrometry. The roots and rhizomes of this plant species were used as the raw material. Hexane and methyl tert -butyl ether (MTBE) were used as extractants. Two extraction schemes were used (exhaustive and sequential), which allowed us to obtain more detailed information on the composition of components of the raw material. The obtained lipophilic extracts were separated into acid and neutral components by treating with NaOH and KOH solutions. The acid components were transformed into methyl ethers by treatment with diazomethane. The neutral components of the unsaponifiable residue were analysed without derivatisation. The fractions enriched with hydrocarbons, ketones, sterols, aliphatic and triterpene alcohols were obtained by chromatographic separation through a column with silica gel. A series of low-polar compounds were identified that have not been detected previously in this kind of raw material. By comparing the mass spectra obtained in the work with the available databases, the following compounds were identified: aliphatic acids with chain length 10-30 carbon atoms (including unsaturated and dicarboxylic), the compounds of cinnamic series, as well as benzoic, salicylic, sterculic, 9,10-octadecadienic and phenylpropanoic acids. More than 90 triterpene and aliphatic compounds of the unsaponifiable residue and 33 components of free and bound acids were identified. In addition to n- alkanes, the hydrocarbon fraction contains also squalene, as well as saturated and unsaturated hydrocarbons with shorter chains. Aliphatic and terpene aldehydes and ketones were detected. Highly active triterpene alcohols and ketones are represented mainly by ursane and oleanane derivatives. The major sterol component (β-sitosterol) is accompanied by cholesterol, campesterol, stigmasterol, stigmast-7-en-3-β-ol and stigmastan-3-β-ol.

A series of ureas containing adamantane and monoterpenoid residues has been synthesised. All compounds were tested in vitro using a pseudoviral system containing the S glycoprotein of the SARS-CoV-2 virus and infectious SARS-CoV-2 viruses of various strains on its surface. Compound 4a demonstrated high activity against four strains of SARS-CoV-2.

The areas adjacent to open coal mining facilities are affected by different kinds of anthropogenic impact, including dust pollution. To reveal the extent of technogenic impact, the parameters characterising the content and composition of 19 priority polycyclic aromatic hydrocarbons (PAHs) in chernozem soils adjacent to the haul road of the Gorlovo anthracite deposit (the Novosibirsk Region) were assessed. It is shown that the maximum total concentration of PAHs (>1000 ng/g) is reached at the distance of 100 m from the source, while the levels higher than the background are detected at a distance of 1000 m. The effect of dominating wind direction and the presence of tree shelter belts were determined to affect the total PAH content in soil but leave their group composition unchanged at a distance of 2000 m from the road. At the same time, the individual composition of PAHs in soils changes with an increase in the distance from the pollution source. The concentration of benz(a)pyrene and total PAH content, calculated for benz(a)pyrene toxic equivalents, were determined in the soils of territories adjacent to the haul road and compared with the current standards in force in the Russian federation (SanPiN). Statistical processing of the results, performed by the principal component analysis, shows that the input of black carbon in the form of anthracite coal dust into soil is most adequately represented by polyarene ratio PHE/(PHE+CHR), where PHE is phenanthrene, and CHR is chrysene. However, the threshold of technogenic load (<0.8), that was previously established for objects in which anthracite is the main source of PAHs, requires confirmation for black soils.

[1]Benzothieno[3,2-b][1]benzothiophene (BTBT) derivatives attract attention in the field of organic optoelectronics due to their stability in air, 2D film formation ability and high charge-carrier mobility. Here we present approaches to the synthesis of new furanyl-substituted BTBT derivatives. The physicochemical properties of the target compounds were studied. It is shown that all materials have high quantum yields of photoluminescence. A thorough analysis of BTBT bromination has been carried out, and the reaction conditions were optimised. It has been shown that a mixture of regioisomers is always formed in this process, but this does not necessarily interfere with further synthesis. A significant reduction in the total reaction time from 48 to 6 hours has been achieved.

Modern trends in the development of structural biology make it relevant to study the structure of biomolecules under the conditions close to natural, i.e., directly in a living cell and at temperatures close to physiological ones. One of the promising technologies that allows approaching this ideal is the targeted introduction of spin labels (for example, nitroxides), followed by investigation using pulsed electron paramagnetic resonance (EPR). Today, the greatest stability in living systems is demonstrated by sterically hindered nitroxyl radicals of the pyrrolidine series with four ethyl groups at a paramagnetic centre, but their relaxation characteristics do not allow measurements by pulsed ESR methods at a temperature above 80 K. Nitroxides with spirocycloalkane fragments surrounding the nitroxyl group are suitable for measurements at higher temperatures, but they are rapidly reduced by the components of living systems. Pyrrolidine nitroxides with two spiro-(2-hydroxymethyl)cyclopentane moieties combine high resistance to reduction with high spin relaxation times at a temperature of 120 K and above. In this work, a hydrophilic chiral radical of this series - (1 R ,5 S ,7 S ,8 R ,12 S ,13 S )-12,13-dihydroxy-1,8-bis(hydroxymethyl)-6-azadispiro[4.1.4.2]tridecane-6-oxyl was obtained and characterised by us for the first time.

The synthesis of ((9 H -(4,5-diazafluorene)-9-ylidene)methyl)arylenes is presented and their physicochemical characteristics are studied by cyclic voltammetry and optical spectroscopy. The target compounds were synthesised from commercially available reagents in three steps using a combination of Suzuki-Miyaura cross-coupling and condensation reactions. It was found that the compounds had a low photoluminescence quantum yield in solution, and 9-(4-([2,2'-bithiophen]-5-yl)phenylidene)-9 H -4,5-diazafluorene demonstrates aggregation-induced luminescence. The crystal structure of 9-(4-([2,2'-bithiophen]-5-yl)phenylidene)-9 H -4,5-diazafluorene was solved by X-ray diffraction analysis. The single crystals of this compound have the elongated plate morphology and exhibit photoluminescence quantum yield of 5 %.

The results of studies of the Ice Complex, lacustrine, and lacustrine-alluvial sediments from the Mamontova Gora section performed in 2022-2023 are analyzed. Optically stimulated luminescence dating indicates that the formation of the lacustrine-alluvial sands of the Elga Group ended 250-242 ka ago, at the end of cold MIS 8, while the overlying lacustrine silts accumulated until 138-126 ka ago corresponding to the late cold MIS 6 - early warm MIS 5e. The average isotopic composition of the Yedoma Ice Complex (MIS 3) syngenetic wedge ice is -(31 ± 2)‰ for δ¹⁸O, -(239 ± 15)‰ for δD, and (8 ± 2)‰ for d_exc. For the first time, we quantify the isotopic composition of the Yedoma Ice Complex textural ice with the average values of -(26 ± 2)‰ for δ¹⁸O, -(201 ± 17)‰ for δD, and (10 ± 4)‰ for d_exc. The formation of lacustrine and lacustrine-alluvial sequences during MIS 7 and MIS 5e was fostered by warmer and likely longer thaw periods and associated permafrost thaw. The degree of warming remains to be estimated for this region.

A classification of periglacial lakes that formed in Svalbard after the Little Ice Age due to the reduction of glaciation is presented. The classification is based on three morphological features: the position of the lake relative to the boundaries of the glacier and the terminal moraine, contact with the glacier, and the damming condition. Combinations of these features allow us to distinguish five types of lakes. Based on the Norwegian Polar Institute cartographic service as of 2008-2012, 705 periglacial lakes of the archipelago were analyzed. Among them, glacier-dammed lakes make up 24%; moraine-dammed lakes, 22%; lakes in contact with the glacier front, 17%; thermokarst lakes over the moraine, 27%; and lakes in contact with the terminal moraine located beyond it, 10%. Dammed lakes and lakes in contact with glaciers compose about 90% of the total area of periglacial lakes in Svalbard. They are actively forming at present due to the destruction of ice banks and moraine ridges. Despite the differences in the relief, type of glaciation, climate, and rate of glaciation reduction in different parts of the archipelago, the ratios between different types of periglacial lakes are similar. This attests to their common genesis and similar features of the moraine landscape. Noticeable differences appear in the ratio of moraine-dammed lakes and lakes in contact with mountain glaciers and cover glaciers. It is likely that during the further deglaciation of the archipelago, the distribution of these types of lakes will be preserved, which makes it possible to assess lake resources and identify potentially dangerous objects and objects of climate monitoring.

This paper provides a detailed review of the methods of active temperature stabilization of frozen soils with an emphasis on stabilization systems with a horizontal evaporator. The experience of Russian and foreign authors in the field of single seasonal cooling devices is presented. The range of seasonal cooling devices applied in Russia and the objects, at which they are installed, are considered. The mechanism of action of both single cooling devices and temperature stabilization systems with a horizontal evaporator is shown. The paper also presents a new experimental installation for thermal stabilization of frozen ground with a horizontal evaporator, on which a number of experiments have been conducted to study refrigerant flows in the circulation circuit of the proposed system under different thermal conditions affecting the evaporator. A description of a full-scale stand is given, and the principle of supplying positive temperature to the evaporator in order to simulate heat removal from the ground and its further dissipation into the atmosphere is described. At present, systems of this type usually use ammonia as a refrigerant; in the proposed system, carbon dioxide is used. It has been shown that the capacity of the installation based on carbon dioxide can be significantly higher than that based on ammonia. The study results make it possible to optimize the configuration of the ground temperature stabilization system with a horizontal evaporator for particular construction sites. The efficiency of the developed system is much better compared to the analogues, which significantly reduces the risk of thawing of frozen ground at operational sites. This is especially relevant at hazardous production facilities working with harmful substances, the ingress of which into the soil imposes a significant ecological trace.

The study and prediction of subsea permafrost conditions hold profound significance in the context of global climate change, the formation of gas hydrates, and the assessment of natural hazards arising from the permafrost thawing. This study presents a forecast of relict subsea permafrost distribution across the Eurasian Arctic shelf through the resolution of a one-dimensional, non-stationary Stefan problem using finite difference methods, facilitated by contemporary software tools and libraries. The mathematical description of the model is presented. Particular attention is paid to the boundary conditions of the model and their synthesis. Calculations take into account the climate clustering of the expansive Eurasian shelf, considering zonal variations in both near-surface air temperature and the temperature and salinity of subsea waters. For the first time, model estimates of the position of the upper boundary of subsea permafrost are presented, and its position is compared with drilling data. Analysis of the influence of boundary conditions on the simulation results and comparison of our results with seismoacoustic and drilling data confirm the good quality of the model. The evolution of subsea relict permafrost in time is represented by a set of three maps for the Late Pleistocene-Holocene time spans. As a result, a high-resolution global two-dimensional map of the thickness of underwater permafrost on the Eurasian shelf was created. Detailed modelling and forecast mapping of the distribution of permafrost table was carried out in well-studied areas. According to our forecasts, a wide distribution of subsea relict permafrost is predicted throughout the Eurasian Arctic shelf. The greatest thickness of relict frozen deposits is confined to the littoral zone of the Laptev and East Siberian seas, as well as the offshore of the New Siberian Islands. In the Pechora and Chukchi seas, mostly poorly developed, close to complete degradation, relict subsea permafrost is predicted.