We report on the synthesis and characterization of new ruthenium indenylidene complexes bearing two unsymmetrical N-heterocyclic carbene (NHC) ligands denoted as RuCl2(3-phenyl-1-indenylidene)bis(1-mesityl-3-R-4,5-dihydroimidazole-2-ylidene) in which R is methyl 7a and cyclohexyl 7b. Complexes 7a and 7b were analyzed using single-crystal X-ray diffraction analysis, elemental analysis, IR, NMR spectroscopy, and HRMS. The catalytic activities of complexes 7a and 7b were evaluated in olefin metathesis reactions: ring-opening metathesis polymerization (ROMP) of cis,cis-1,5-cyclooctadiene (COD) and ringclosing metathesis (RCM) of diethyl diallyl malonate (DEDAM) as well as in the isomerization of allylic alcohols. Complexes 7a and 7b failed to initiate the reactions at room temperature in all tested reactions, which might be due to the high thermal stability and low degree of lability of the Ru-CNHC bonds. At 80 °C, the complex 7a showed the best performance due to an increased initiation and a decreased steric obstruction towards the incoming substrates.

The review article summarizes the results of studies conducted in the field of polymer composites obtained by various methods. An important industrial activity is structured around the development of polymeric materials and composites based on them. Composite materials having a matrix comprised of a polymeric material (polymers, oligomers, copolymers) are highly numerous and diverse. They are widely used in the industry for the manufacture of vitreous, ceramic, electrically insulating coatings, as adsorbents in the treatment of wastewater from heavy metal ions, and in the production of ion-exchange membranes. Composite materials have unique properties such as a large surface area, thermal and mechanical stability, good selectivity against various contaminants, and cost-effectiveness. The review presents the physicochemical and structural characteristics of composite materials based on synthetic polymers (polymer-carbon, polymerclay composites), polymeric heterocyclic and organosilicon compounds. Used across a variety of applications, polymer-carbon and polymer-clay composites are effective in removing organic and inorganic contaminants. However, when used as adsorbents for large-scale production, they have yet to achieve optimum performance. Hybrid materials obtained by the sol-gel method deserve special attention. This method can be conveniently used to influence the composition and structure of the surface layer of such materials as adsorbents of heavy and noble metals, catalysts, membranes and sensors for applications in biological antibiosis, ion exchange catalysis, etc. Such composites are characterized by their increased mechanical strength and thermal stability, as well as offering improved thermochemical, rheological, electrical and optical properties.

The features of the surface changes of the RbTe_1.5W_0.5O₆ photocatalyst during polymerization processes involving methyl methacrylate (MMA) under irradiation with visible light λ= 400–700 nm at a temperature of 20–25 °C, as well as regeneration conditions for its reuse, have been studied. The realization of a chemical reaction in a mixture of a photocatalyst and a monomer is determined by its kinetic parameters and the concentration of reacting particles. The formation of OH• radicals, which are active in radical polymerization, occurs in this case by both ways: interacting between water molecules adsorbed on the surface, as well as during the recovery of oxygen dissolved in water. Due to the high reactivity of the hydroxyl radical, an active process of radical polymerization of MMA could be expected. However, the formation of polymethyl methacrylate (PMMA) in the reaction takes place with a low conversion – the formation of 5–10% polymer, which is related to changes on the surface of the complex oxide RbTe_1.5W_0.5O₆ during the reaction. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) methods have been used to investigate the catalyst surface. The presence of organic and polymer substrates was revealed on the catalyst surface after the reaction. As a result of the catalyst treatment by ultrasound in an aqueous emulsion, polymer macromolecules are not identified on the surface, but chemically adsorbed monomer and oligomers formed under the ultrasound destruction of the polymer are presented. Other methods of cleaning the catalyst surface by washing in different solutions as chloroform and tetrahydrofuran also are not effective and cause the adsorbates transformations on the surface. It leads to decreasing the RbTe_1.5W_0.5O₆ catalyst's activity for repeated polymerization. Thus, to successful regeneration of the catalyst's powder not only ultrasound treatment is required, but also heating it at 300–400 °C to remove organic substrates.

Extraction is a versatile and relatively simple method for extracting rare and scattered elements, producing good results at minimal expenses in terms of reagents and equipment. Information about the thermal effects and kinetic dependencies of the extraction process is essential for predicting and counteracting fluctuations in external conditions. In this work, the thermodynamic and kinetic parameters of the iodine extraction process were studied using model solutions that contained sodium chloride with an ionic strength of 0–5 mol/l as a background mineralization. This composition closely corresponds to natural and man-made waters of oil and gas condensate fields. A mixture of tri-n-butyl phosphate and isooctane was used as the extractant. In order to evaluate thermodynamic parameters, extraction isotherms were constructed at temperatures of 278 and 288 K. For different background ionic strength values, equilibrium extraction parameters were determined, including the extraction degree, distribution coefficient and equilibrium constant, as well as changes in the enthalpy, entropy and Gibbs energy of the process. A study of the kinetic dependencies of iodine extraction from aqueous solutions under different ionic strength values at temperatures of 278, 288 and 293 K allowed the true and apparent orders of reaction to be established, along with the activation energy of the extraction process. Across the entire range of the studied ionic strength values, iodine extraction occurs spontaneously with high distribution coefficients and an extraction degree of over 86%. The kinetic parameters of the iodine extraction process (activation energy, temporal and concentration reaction order) indicate the diffusion nature of the rate-determining step, the presence of intermediate complexation stages and the absence of temperature effects on the reaction rate.

The phytochemical study of Leptopyrum fumarioides started in 2011 and since then 14 volatile compounds have been identified by GC-MS. 7 flavonoids and 4 alkaloids have been isolated and 2 of them have been recognized as new natural compounds. The structures of the natural products have been determined and ascertained by MS, as well as IR, 1D NMR and 2D NMR spectroscopic methods. The antioxidant, antimutagenic, antiproliferative, hepatoprotective, immunomodulatory, and anticancer activity of Leptopyrum fumarioides extracts and some isolated pure compounds were examined. The new alkaloids leptopyrine (3) and leptofumarine (4) were identified. Leptopyrine (3) is a new type of dimer alkaloid of benzylisoquinoline and simple isoquinoline with imine nitrogen. Leptofumarine (4) is the first example of aporphine and benzylisoquinoline alkaloid with two ether bridges which have head-to-head and tail-to-tail coupling. This review clearly shows that the phytochemical study of plant species is just beginning and requires more detailed and comprehensive study.

In recent years, the biodegradation of polyethylene glycol terephthalate has become an important direction in solving the problem of environmental pollution with plastic waste. This review generalizes the latest data on various microorganisms capable of biodegrading polyethylene glycol terephthalate. The mechanisms of enzymatic reactions of polyethylene glycol terephthalate hydrolysis and the structure of biodegradation enzymes are elucidated. Challenges to the industrial implementation of polyethylene glycol terephthalate biodegradation are considered along with proposals on the promotion of appropriate waste disposal technologies. Biodegradation comprises a promising method for the environmentally friendly and efficient disposal of waste plastics. So far, no commercial biodegradation technologies for recycling polyethylene glycol terephthalate have been developed. This area is attracting increased research attention, which is expected to result in the appearance of cost-effective and high-tech biodegradation processes. Future advances are likely to be based on synthetic biology and metabolic engineering strategies capable of constructing artificial microbial consortia and modifying microbial polyethylene glycol terephthalate hydrolases aimed at a more complete biodegradation and bioconversion of polyethylene glycol terephthalate and other complex polymers.

This article reviews data on antimicrobial additives used in the food industry for preserving the quality of food products. The use of conventional antimicrobial additives, including artificial preservatives (benzoic and sorbic acids and their salts), causes a negative response among consumers. As a result, such products are gradually disappearing from the market. At the same time, antimicrobial additives of natural origin are gaining in popularity, increasingly attracting the attention of both Russian and foreign researchers. In this article, the main antimicrobial additives of animal, vegetable and microbial origin are considered. Antimicrobial additives of animal origin are represented by lysozyme and lactoperoxidase enzymes, lactoferrin and pleurocidin peptides, as well as by chitosan, a derivative of chitin. Plant substances that exhibit antimicrobial and antioxidant properties include herbs and spices, both in native and dried form, as well as separately extracted plant components, such as essential oils, phenolic compounds and organic acids. Substances of microbial origin, in particular bacteriocins, comprise another promising class of antimicrobial additives. These forms represent smaller polypeptide molecules synthesized on ribosomes, which exhibit antagonistic activity against closely related groups of bacteria. Bacteriocins, such as nisin, natamycin, pediocin, enterocin and plantaricin, may exhibit bactericidal properties, at the same time as having little therapeutic value and no negative effect on the human intestinal microflora. This makes them different from antibiotic preparations. The conducted review confirms the prospects of using the considered additives in the composition of both food products and active packaging systems.

Effects of the infectious load of the causal agent Clavibacter michiganensis sps. Sepedonicus (Cms) of ring rot of potatoes on hydrogen peroxide and cAMP levels in potato plants in vitro were studied on three transgenic lines of the Scarb cultivar: line L17.2 – plants transformed with the native gene of glucose oxidase gox from the highly active fungal strain Penicillium funiculosum 46.1; line M7.3 – plants transformed with the modified gene gox-mod; and line Pb14.10 – plants transformed with a vector without a target gene. In addition, non-transgenic plants of the same cultivar (medium resistant against Cms), Lugovskaya (resistant against Cms) and Lukyanovsky (susceptible to Cms) were examined. In the plants infected with Cms (0.2х10⁸ cells/ml), the dynamics of cAMP and Н2О2 indicated a balanced system signal “root–stem”. The Cms titre (2х10⁸cells/ml) caused a systemic increase in the concentration of Н₂О₂ in the organs of almost all plant cultivars; however, a systemic increase in the level of cAMP occurred only in the Lugovskaya cultivar. In all the studied transgenic lines, cAMP levels remained at the control level, accompanied by both local and extensive necrosis. In transgenic potato lines, the observed decrease in protective responses (both local and extensive necrosis) is likely to be associated with an extremely high baseline level of endogenous hydrogen peroxide and an imbalance in cAMP levels. The introduction of the gox gene into potato plants was found to increase their resistance against high Cms titres.

A research study into the molecular weight distribution of inulins of various origin was conducted to elucidate the mechanism of their self-organization in concentrated solutions. Using the conventional turbidimetric titration method based on integral and differential molecular weight distribution curves, the following inulin samples were examined: commercial girasol (A), experimental girasol (B) and experimental chicory (C). Inulin A and B samples were found to include three macromolecular fractions (isoforms), each exhibiting a narrow molecular weight distribution. An increase in inulin concentration in the solution leads to selforganization of macromolecules, resulting in a more turbid solution at the point of maximum and the appearance of new isoforms. An increase in polymer concentration in inulin A leads to an increase in the aggregates of isoforms 3 and 5. Conversely, in inulin B, aggregates dissolve making isoforms convert from high- to low molecular weights. In inulin C, all four inulin isoforms are clearly represented. An analysis of the interaction of macromolecules in a concentrated solution confirmed the applicability of turbidimetric titration for determining the molecular weight distribution of polymers, along with such costly procedures, as highperformance size exclusion liquid chromatography, ultracentrifugation and light scattering. Research into the properties of unique inulins may significantly expand the range of their practical application.

The performed condensation of p-aminobenzoic acid with D-mannose produced N-mannopyranosylamine with ? configuration at the anomeric centre, which was confirmed by vibrational spectroscopy. The reactivity of the synthesized product in the processes of acid hydrolysis and thermal oxidation in a freely aerated medium was studied. A hydrolytic stability study showed p-(N-β-D-mannopyranosyl)- aminobenzoic acid, which is stable in ethanolic media, to gradually hydrolyse upon heating (50 °C) in acidic aqueous solutions, as confirmed by FTIR spectroscopy and thin-layer chromatography. Upon thermal oxidation, the synthesized product shows sufficient stability when heated up to 30–50 °C. However, a further increase in temperature to 70 °C accelerates destruction, which is manifested in an increase in the band intensity of 1690 cm^-1 (vO=C–C=N) in the spectra of the second derivatives of thermostated samples. This process is assumed to involve direct oxidation of N-glycosylamine, most likely in the acyclic form of enaminol. Additionally, the nature of N-glycosylation by-products was studied by electron and oscillatory spectroscopy. These studies indicated the formation of melanoids – coloured products of deep destruction, which might exhibit growth-regulating and other types of biological activity. The main structural fragments of melanoids are assumed to be formed in solutions through the interaction of enaminol forms with α-dicarbonyl derivatives. Our experimental data obtained earlier also indicate the biological activity of melanoids in arylaminocarbonyl reactions, thereby allowing the technology of obtaining functional products of different stages of sugar-amine interactions to be combined within a single synthesis operation. The feasibility of this approach is determined by the availability of reagents, mild synthesis and product separation conditions, as well as by their environmental friendliness.

A study into the effect of low concentrations of caffeine and colchicine alkaloids on the growth and biofilm formation of rhizospheric microorganisms – Gram-positive Rhodococcus qingshengii and Gramnegative Rhizobium radiobacter – is presented. Alkaloids present in plants effectively protect them from being eaten by animals of various taxa, as well as from fungal and bacterial infections. Forming part of a complex, evolutionary system of plant-microbial interactions, they occur naturally in the medium at low concentrations. One of the decisive factors in the spread of microorganisms is the formation of biofilms. In the study, alkaloids were added to the bacterial suspension at time intervals corresponding to distinct phases of biofilm formation. In order to determine the level of biofilm formation, bacterial cells were stained with crystal violet. The optical density of the suspension was used to assess the effect of alkaloids on bacterial growth and biofilm formation. The effect of caffeine and colchicine in concentrations of 10-5 g/L on the growth and biofilm formation of microorganisms is revealed for the first time. Although alkaloids did not affect the growth of the suspension of Gram-positive Rhodococcus qingshengii, they effectively suppressed the suspension of Gram-negative Rhizobium radiobacter. While Rhodococcus qingshengii showed greater sensitivity to alkaloids at the stage of biofilm formation, Rhizobium radiobacter was more sensitive at the stage of "mature" biofilms. The effect of alkaloids could be expressed both in terms of suppression and enhancement of biofilm growth. It can be assumed that the mechanism of action of plant alkaloids at the level of signaling systems and bacterial quorum sensing allows the protective function to be maintained even with a significant decrease in the number of alkaloids under conditions of permanent antagonism in which they are constantly being destroyed by phytopathogens.

A humic preparation obtained through alkaline extraction of humic-containing raw materials at the All-Russian Research Institute of Reclaimed Lands (branch of the V. V. Dokuchaev Soil Science Institute) is presented. The aim of the work is to study the effect of the humic preparation – named BoGum – on the remediation of oil-contaminated podzols. In a model experiment for soil remediation, artificially contaminated with oil in an amount of 5%, BoGum was used in 3 doses: as a stimulant of aboriginal microflora (300 l/ha), as a fertiliser (3000 l/ha), and as a sorbent (30000 l/ha). BoGum was found to be more effective as a stimulator of aboriginal microflora, whose maximum was observed one month following application, while the degree of destruction of oil over the two months of the experiment was 40.1%. Over the course of the experiment, it was determined that humic substances of the preparation were a more affordable source of nutrition for the soil microflora when BoGum was used as a sorbent; the breakdown of oil was the lowest when petroleum hydrocarbons were inaccessible to microorganisms due to sorption. The maximum degree of breakdown (44.9%) occurred with the combined use of the microbial preparation MicroBak (development of the Institute of Biochemistry and Physiology of Microorganisms of the Russian Academy of Sciences) and the humic preparation BoGum at a dosage of 300 l/ha. The preparation demonstrated a synergistic effect, which affected the active development of both hydrocarbon-oxidising microorganisms and aboriginal microflora. The percentage of the hydrocarbon-oxidising microorganisms from the total number of heterotrophs in all experimental variants was maximum in two weeks; this was reduced at different intensities. Calculated multiple regression equations were used to estimate the physiological influence of the groups of microorganisms on the degree of degradation being investigated.

In this work, nine varieties of red currant cultivars, recognized for use in the Sverdlovsk Oblast, were studied. According to the conducted analysis, the Epsilon cultivar demonstrated the highest antioxidant indicators (mmol/dm3eq) of 13.772 ±0.275. For comparison, the Ilyinka and Luchezarnaya cultivars showed the values of 12.826 ±0.257 and 11.933±0.239, respectively. The late ripening cultivar Zeta showed the lowest antioxidant value of 6.428±0.129 mmol/dm3eq. At the same time, the highest content of flavonoids was characteristic of such red currant cultivars (mg/100 g of edible part, variety) as Epsilon – 50.3±0.9, Beta – 44.2±0.9, Ogni Urala – 45.7±0.9 and Zeta – 17.3±0.3, while the Lychezarnaya cultivar showed the lowest value of 16.1±0.3. In terms of anthocyanins, the highest values (mg of cyanidin-3-glycoside/100 g of edible part) were observed in the Kapitalina, Ilyinka and Lychezarnaya cultivars, equalling 29.1±0.6, 38.1±0.7 and 41.2±0.8, respectively. The average ripening cultivar Alaya Zorka showed the lowest anthocyanin value of 11.9±0.2. The Kapitalina, Ilyinka and Luchezarnaya cultivars demonstrated the highest amounts of phenolic substances (mg of gallic acid/100 g of edible part) of 212.9±4.3, 235.1±4.7 and 168.3±3.3, respectively. In terms of this indicator, the Beta cultivar showed the lowest value of 114.1±2.3. The consumer characteristics of the cultivars were studied, including their acidity, as well as the content of total and reducing sugars. The obtained results can be used when selecting dietary supplements based on red currant berries and determining the nutritional value of diets in order to increase their overall antioxidant activity.

In conformity with a constant tightening of environmental requirements, sulfur compounds are removed from the composition of diesel fuel using the hydrotreating method. However, this has led to a significant deterioration in the anti-wear properties of diesel fuel. To restore the lubricity, oxygen-containing compounds are added to diesel fuel, including carboxylic acids and their amide derivatives, as well as esters, polyamines and other organic compounds. The recommended concentration of the additive, which ranges from 0.015 to 1.0 wt %, is dependent on its specific properties. In addition to anti-wear additives, cetaneenhancing, depressant-dispersing and other additives are added to diesel fuel to correct the properties of the fuel. A method for producing an esterification product for improving the properties of diesel fuel is described. It is shown that an esterification product containing up to 65% fatty acid esters can be obtained at a temperature of 110–115 °С and a process duration of 120–240 minutes when using 3–5 wt % ion-exchange resins for fatty acids. The effect of the additive content on the lubricating properties of diesel fuel is investigated. When 0.5 wt % or more is added, the corrected wear spot diameter is reduced from 615 to 420 µm; when 1.5 wt % is added, it is further reduced to 230 µm. The addition of esterification product to the diesel fuel is shown to result in an increase in the cetane number of initial fuel. When adding 6.0 wt % of the esterification product under development, the cetane number of the fuel is increased from the original 43.0 units to 51.6. In this case, the esterification product can be used as a component for preparing a mixture of biodiesel fuel B6-B20, according to GOST 33131-2014.

The cleaning of industrial gases from dust is one of the most significant current environmental protection problems. The search for new, more advanced and effective ways to clean dust gases and dust collector designs is based on the diversity of technological conditions for dust formation, the physicochemical properties of gases and trapped particles, and an increase in technical and economic requirements for cleaning processes. When cleaning hot or chemically aggressive gases and capturing abrasive dust, the use of electrostatic precipitators, bag, fibrous and granular filters is often associated with difficulties in protecting the devices from harmful factors or ensuring sufficient cleaning efficiency. The design features of slotted filters permit their use in solving such problems. An engineering method for calculating slotted filters developed on the basis of theoretical ideas and experimental studies is used to model and design slotted filters with specified performance indicators to ensure high cleaning efficiency and low hydraulic resistance. This technique is based on theoretical patterns of filtration using basic dust particle deposition mechanisms on isolated cylinders in relation to the stationary stage of the filtration process. A computer program that simulates the process of cleaning dusty gases in slotted filters has been developed. This makes it possible to determine the optimal operating parameters, design dimensions and regeneration conditions of slotted filters based on a specified cleaning efficiency and hydraulic resistance, taking into account the properties of dust and gas during prolonged continuous operation of the filter.