The transformation of organic matter in the soil is largely determined by hydrolytic enzymes. Under the conditions of climate change, understanding the mechanisms of microbial response is of particular importance for predicting the carbon cycle. Until now, the effect of drought duration and frequency on soil hydrolytic enzymes has been little studied. A multifactorial field manipulation experiment was carried out, simulating in the presence of plants and without them: two short-term droughts, a long-term drought, and an optimal level of soil moisture. The maximum reaction rate V-max, Michaelis constant K-m, and catalytic efficiency K-a of five groups of enzymes involved in the carbon cycle (cellobiase, glucosidase, xylanase), phosphorus (phosphatase), and nitrogen (chitinase) were determined. In phosphatases, glucosidases, and xylanases, V-max decreased during short-term drought. During prolonged drought, the V-max value of phosphatases, cellobiohydrolases, and xylanases decreased and increased in chitinases, while remaining unchanged in glucosidases. Both long-term and short-term droughts led to an increase in K-m and a decrease in catalytic efficiency (K-a) for almost all enzymes. Short-term droughts were not a "weakened version" of a long-term drought, but had their own specifics-a decrease in K-m of glucosidases, which led to an increase in K-a. Long-term drought was characterized by an increase in V-max of chitinases and spatial variability of V-max of phosphatases and glucosidases. The influence of the presence of plants was secondary and manifested itself only during short droughts. The reversibility of the effect of drought on V-max, K-m, and K-a decreased in the series first short-term drought > second short-term drought > long-term drought due to an increase in the total duration of the stress impact.

New insoluble polymer silver-containing nanocomposites are synthesized by the thermal treatment of a polymer complex based on polyacrylonitrile without the use of an additional reducing agent. The resulting composites are paramagnetic and have a spin concentration of about 1017−1018 spin/g and an average size of silver nanoparticles of 5−8 nm. The electron paramagnetic resonance is used to monitor the synthesis of nanosystems in time. It is found that the nanocomposite is formed via two main stages through the reduction of silver ions and the further development of nanoparticles, while the polymer matrix can undergo some changes and contribute to the overall magnetism of the resulting composite.

The formation of new polymeric nanocomposites with silver nanoparticles incorporated into the matrix of 1-vinyl-1,2,4-triazole copolymers with vinyl acetate was studied. Water-soluble nanocomposites containing different amounts of silver nanoparticles with an average size of 6–13 nm were synthesized varying the reaction conditions. The physicochemical, optical, thermal, and structural properties of the nanocomposites were studied by IR and UV spectroscopy, transmission electron microscopy, X-ray diffraction and atomic absorption analyses, and thermogravimetry. The antimicrobial activity of the initial copolymers and related nanocomposites was evaluated with respect to test microorganisms.

The interaction of vinyl acetate with 1-vinyl-1,2,4-triazole under conditions of free radical initiation of functional copolymers, containing hydrophilic triazole and hydrophobic acetate fragments in their structure, are synthesised. In order to obtain copolymers of different composition that are well-soluble in water and organic solvents, the ratio of monomers in the initial reaction mixture was varied. By evaluating the reactivity of monomers, it was established that 1-vinyl-1,2,4-triazole exhibits greater reactivity compared to vinyl acetate. Copolymers exhibiting the properties of high-resistance organic semiconductors, characterised by a specific electrical conductivity of the order 10(-14)-10(-15) S/cm, have high resistance to thermal-oxidative degradation: the beginning of thermal decomposition occurs at temperatures of 300-330 degrees C. The structure, composition and physicochemical properties of the copolymers were characterised by elemental analysis methods, IR and NMR H-1 spectroscopy, turbidimetric titration, as well as thermogravimetric analysis.

New cross-linked insoluble polyfunctional copolymers with triazole fragments and vinyloxy groups in the side chain were synthesized by radical copolymerization of 1-vinyl-1,2,4-triazole with diethylene glycol divinyl ether. The dependence of the sorption activity with respect to the gold ions in acidic solutions on their nature and concentration was studied. The copolymers obtained were found to possess high sorption activity; they efficiently extracted gold ions from solutions of complex composition.

Синтезированы новые серосодержащие сополимеры на основе поливинилхлорида методом ­нуклеофильного замещения атомов хлора на атомы серы с использованием тетра- и пентасульфидов натрия. Показана возможность карбонизации таких сополимеров с образованием серосодержащих углеродных материалов и остаточным содержанием хлора около 2 мас. %.

A novel cross-linked copolymer of 1-vinyl-1,2,4-triazole and N , N ′-methylene-bis-acrylamide was synthesized via free radical copolymerization. Sorption capacity of the copolymer toward palladium chloride( ii ) in acid aqueous solutions was investigated. Sorption properties and efficiency of the polymer as a sorbent were evaluated. Mechanism of the copolymer interaction with palladium complex was identified by methods of IR- and Raman spectroscopy and elemental analysis.

New functional copolymers of different composition with triazole and acetate fragments in the macromolecules were synthesized by free radical copolymerization of 1-vinyl-1,2,4-triazole with vinyl acetate. The reactivity of the comonomers was studied and the monomer copolymerization constants were calculated. The structure and composition of the copolymers were determined by elemental analysis, IR and 1H NMR spectroscopy.

New sulfur-containing copolymers based on poly(vinyl chloride) have been prepared by the nucleophilic substitution of chlorine atoms by sulfur atoms using sodium tetra- and pentasulfides. It has been shown that these copolymers can be carbonized to produce sulfur-containing carbon materials with residual chlorine content about 2 wt %.

New copolymers containing reactive vinyltriazole units and polyvinylene blocks with conjugation system promising as materials with special electrical, physical, catalytic, and sorption properties have been prepared by the reaction of poly(vinyl chloride) with sodium salts of 1,2,4-triazole and 1,2,3-benzotriazole in a dimethylformamide medium.

New polymer silver nanocomposites were synthesized using a copolymer of 1-vinyl-1,2,4-triazole with crotonaldehyde as the silver ion reducing agent and stabilizer of metal nanoparticles. The formation of the metallic phase in the nanoscale state was confirmed by UV spectroscopy and X-ray phase analysis. According to the transmission electron microscopy, nanoparticles have sizes of 2—14 nm and are uniformly distributed in the volume of the polymeric matrix.

A radical copolymerization of 1-vinyl-1,2,4-triazole (VTA) with 1-vinyl-4,5,6,7-tetrahy-droindole (VTHI) was studied. New thermally stable functional copolymers of different composition, well soluble in organic solvents were synthesized. It was found that VTA has higher reactivity as compared to VTHI. A new soluble polymeric nanocomposite with metallic silver nanoparticles encapsulated into the matrix of synthesized copolymer was obtained.

Magnetic fluid-loaded liposomes (MFLs) were fabricated using magnetite nanoparticles (MNPs) and natural phospholipids via the thin film hydration method followed by extrusion. The size distribution and composition of MFLs were studied using dynamic light scattering and spectrophotometry. The effective ranges of magnetite concentration in MNPs hydrosol and MFLs for contrasting at both T2 and T1 relaxation were determined. On T2 weighted images, the MFLs effectively increased the contrast if compared with MNPs hydrosol, while on T1 weighted images, MNPs hydrosol contrasting was more efficient than that of MFLs. In vivo magnetic resonance imaging (MRI) contrasting properties of MFLs and their effects on tumor and normal tissues morphology, were investigated in rats with transplanted renal cell carcinoma upon intratumoral administration of MFLs. No significant morphological changes in rat internal organs upon intratumoral injection of MFLs were detected, suggesting that the liposomes are relatively safe and can be used as the potential contrasting agents for MRI.

Sorbtion conditions, the mechanism of interaction and sorption characteristics of cross-linked copolymers of 1-vinyl-1,2,4-triazole with divinylsulfide with various ratio of components were determined.

Hydrophilic copolymer was obtained by radical copolymerization of 1-vinyl-1,2,4-triazole with sodium acrylate and used as a stabilizing matrix for metallic silver nanoparticles. The synthesis of metallopolymer nanocomposite was performed by chemical reduction of silver ions up to the zerovalent state. The formation of the metallic phase in the nanoscale state was confirmed by UV spectroscopy and transmission electron microscopy. Silver nanoparticles have the sizes of 2–12 nm and are uniformly distributed in the volume of the polymer matrix. Antimicrobial activity of the initial copolymer and polymer nanocomposite in relation to grampositive and gram-negative microorganisms was studied. It was found that the obtained nanocomposite is characterized by a high antimicrobial activity: bacteriostatic concentration varies in the range from 0.5 to 8 g mL–1, the bactericidal concentration is from 1 to 18 g mL –1 .

Бифенил 2,3-диоксигеназа – ключевой фермент в бактериальной деструкции бифенила и полихлорированных бифенилов (ПХБ), являющихся высокотоксичными устойчивыми соединениями. Исследовано разнообразие bphA1-генов, кодирущих -субъединицу бифенил 2,3-диоксигеназы, бактерий-деструкторов бифенила, входящих в состав микробного сообщества донных отложений прибрежной части Берингова моря (район порта Анадырь). Из накопительной культуры, полученной в результате инкубации образцов донных отложений с бифенилом, была выделена тотальная ДНК для дальнейшего ПЦР-анализа с использованием вырожденных праймеров, комплементарных бактериальным генам -субъединиц бифенил 2,3-диоксигеназ. Методом клонирования ПЦР-продукта выявлены три типа генов ароматических диоксигеназ, филогенетически близких генам подсемейства бифенил/толуол диоксигеназ и 3-фенилпропионат диоксигеназ бактерий порядка Actinomycetales.

The results on investigation of the catalytic properties of platinum-containing, tungstate-modified zirconium dioxide in the hydroisomerization reaction of n -heptane or a n -heptane-benzene mixture have been presented. It has been shown that n -heptane isomerization on the catalysts synthesized was effective in the presence of benzene at 200–225°C. It has been found that the catalytic activity of the Pt/WO 4 2− /ZrO 2 catalyst decreases with increasing reaction temperature (250–280°C). The catalysts have been examined by the DSC method. It has been shown that the amount of coke deposed on the catalyst surface increases and its resistance to burning in regeneration is enhanced with an increase in the hydroisomerization reaction temperature.

New copolymers of 1-vinyl-1,2,4-triazole with N-vinyl-4,5,6,7-tetrahydroindole of different compositions were synthesized. The processes of doping them with diiodine and electrophysical properties were studied. An increase in the electrical conductivity of the diiodinedoped copolymers by seven orders of magnitude due to the formation of charge-transfer complexes was observed.