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Coumarins with terpene and tert‐butyl substituents were synthesized via Pechmann condensation reaction. New derivatives were investigated in different model system for the exhibition of antioxidant, radical scavenging and membrane‐protective activities. It has been found that 4‐methylcoumarin derivatives with monoterpene moieties exhibit high antioxidant activities. The most active and promising for further investigations is 5‐hydroxy‐6,8‐diisobornyl‐4‐methylcoumarin, containing two isobornyl substituents on the benzopyran ring.

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The results from studies of aerosol in the Arctic atmosphere are presented: the aerosol optical depth (AOD), the concentrations of aerosol and black carbon, as well as the chemical composition of the aerosol. The average aerosol characteristics, measured during nine expeditions (2007–2018) in the Eurasian sector of the Arctic Ocean, had been 0.068 for AOD (0.5 µm); 2.95 cm−3 for particle number concentrations; 32.1 ng/m3 for black carbon mass concentrations. Approximately two–fold decrease of the average characteristics in the eastern direction (from the Barents Sea to Chukchi Sea) is revealed in aerosol spatial distribution. The average aerosol characteristics over the Barents Sea decrease in the northern direction: black carbon concentrations by a factor of 1.5; particle concentrations by a factor of 3.7. These features of the spatial distribution are caused mainly by changes in the content of fine aerosol, namely: by outflows of smokes from forest fires and anthropogenic aerosol. We considered separately the measurements of aerosol characteristics during two expeditions in 2019: in the north of the Barents Sea (April) and along the Northern Sea Route (July–September). In the second expedition the average aerosol characteristics turned out to be larger than multiyear values: AOD reached 0.36, particle concentration up to 8.6 cm−3, and black carbon concentration up to 179 ng/m3. The increased aerosol content was affected by frequent outflows of smoke from forest fires. The main (99%) contribution to the elemental composition of aerosol in the study regions was due to Ca, K, Fe, Zn, Br, Ni, Cu, Mn, and Sr. The spatial distribution of the chemical composition of aerosols was analogous to that of microphysical characteristics. The lowest concentrations of organic and elemental carbon (OC, EC) and of most elements are observed in April in the north of the Barents Sea, and the maximal concentrations in Far East seas and in the south of the Barents Sea. The average contents of carbon in aerosol over seas of the Asian sector of the Arctic Ocean are OC = 629 ng/m3, EC = 47 ng/m3.

The purpose of the article is to substantiate the necessity and compile recommendations for improvement of the process of development and conduct of cluster policy in agrarian sphere during realization of the concept of economic growth by the example of modern Russia. As methodological provision, the research uses the proprietary methodology of analysis of development of agrarian sphere of economy. As a result of the use of this methodology and analysis of development of agrarian sphere of modern Russian, the authors come to the conclusion that it has a lot of negative tendencies, which causes necessity for improvement of policy in this sphere. For this, the authors offer to use clustering. The authors develop the Pyramid of optimal economic growth and the Model of realization of the concept of economic growth on the basis of conduct of cluster policy in agrarian sphere.