The article presents the results of a chemical and phase composition study of ash obtained from the aerial parts of three horsetail species growing in different regions of Primorsky Krai, namely forest (Equisetum sylvaticum L.), wintering (Equisetum hyemale L.) and field (Equisetum arvense L.) horsetail. It is shown that the conditions for processing raw materials affect the content of silicon dioxide (32–98%) in the ash residues. X-ray phase analysis has shown that the amorphous or amorphous-crystalline state of ash residues depends on the conditions of their production. The absorption bands typical for amorphous silicon dioxide are observed in the IR spectra of ash samples, which correspond to bending (467 cm-1 ) and stretching vibrations (802 and 1092 cm-1 ) of Si-O-Si siloxane bonds. The elemental analysis of silicon-containing products indicates an increase of silicon dioxide content in the samples with an increase in acid concentration during the processing of the aerial part of the horsetails, which also depends on the plant species: the field horsetail contains the lowest quantity of SiO2 as compared to the forest and wintering horsetails, but is characterised by a high content of potassium and calcium compounds. The sorption characteristics of ash obtained from the aerial part of horsetails are assessed: iodine adsorption capacity (5–42%) and methylene blue (164–260 mg/g) and methyl orange (40–241 mg/g) organic dye adsorption capacities. The obtained information can be used in the development of sorbents from vegetable raw materials for the purification and after-purification treatment of natural and waste waters from pollutants of various types.

The presence of water complexes and clusters in hydrolysis and hydration reactions implies complex multi-step processes involving various mechanisms. The concentration of neutral and charged complexes and clusters in the reaction mixture affects the rate and mechanism of hydrolysis. Therefore, the aim of this work was to calculate the concentrations of the complexes and clusters involved in gas -phase hydrolysis of thionyl chloride, as well as to establish the most probable reaction channels. Based on the thermodynamic data obtained by the B3LYP/6–311++G(2d,2p), MP2/aug-cc-pVTZ and G4 methods of quantum chemical modelling, the gas-phase concentrations of the complexes and clusters of water and thionyl chloride, as well as the hydrolysis products of the latter, were calculated. The structures of water complexes of composition (H₂O)_n (n = 1-5.8) were identified and optimised. Acyclic structures of the (H2O)4 and (H2O)5 complexes were identified in the gas phase having concentrations different from those calculated in cyclic complexes. Calculated concentrations of charged complexes and clusters (H+ )∙(H₂O)_n and (H₂O)_n·(OH^-) Cl^-(H₂O)_n, SOCl⁺(H₂O)_n, (SOCl₂(H₂O)_n) - are negligible. Therefore, the assumption concerning the hydrolysis of formed or existing ionic particles in the gas phase inside water clusters can be excluded. Concentrations of SOCl₂(H₂O)_n and HCl (H₂O)_n neutral clusters range from 1014 to 101 molecules/cm3 , depending on the number of water molecules in a cluster. SOCl₂(H₂O) and HCl(H₂O) are characterised by the highest concentration. A calculation of SOCl₂(H₂O)_n cluster concentrations was performed under the assumption that the concentration of thionyl chloride is equal to the concentration of saturated water vapour, which is quite possible near industrial facilities for the production of high-capacity current sources. The most probable channels for hydrolysis are presented by reactions of complexes and clusters having the highest concentrations. These reactions of (H₂O)_n and SOCl₂(H₂O)_n neutral clusters are in a good agreement with the results of previous work. 

In this article, a description of the photochemical degradation of phenol with TiO₂ nanoparticles for the treatment of toxic substances in water basins is presented. Such research is of great relevance due to the discharge of wastewater into clean water basins resulting in a contamination of ecosystems with very ecological consequences. Due to the seemingly inevitable reduction in the world’s freshwater reservoirs, finding new methods for the high-level purification of contaminated waters so as to minimise the toxic substance content is of paramount importance. Composition and quantitative analysis of the photolysis solution was carried out using the gas chromatographic method. TiO₂ nanopowders were prepared using the sol-gel method from titanium IV isopropoxide (TTIP), isopropyl alcohol and ammonium hydroxide precursors under normal conditions without any post-heat treatment for crystallisation. The nanocrystalline rutile-phase TiO2 powders were characterised by X-ray powder diffraction (XRD). The size of nanoparticles as confirmed by transmission electron microscopy (TEM) was about 10–20 nm, while the Brunauer–Emmett–Teller (BET) specific surface area of the rutile nanopowder was 159.6 m²/g. The photocatalytic performance of the synthesised nanopowders photochemical was observed to enhance degradation of the phenol solution under UV irradiation. The phenol degradation was quantitatively analysed using a 6890N GC-MSD gas chromatograph with an Agilent 5975 highperformance mass-selective detector. Degradation of phenol in the presence of TiO2 nanopowders yielded a rate of 99%. 

This paper provides an overview of the features specific to the nuclear magnetic resonance (NMR) of paramagnetic molecules. These features can be attributed to the hyperfine or electronic coupling between unpaired electrons, which are localised on the coordinating ion, and resonant nuclei. That leads both to the paramagnetic broadening and to the paramagnetic shifts (contact and pseudo-contact ones) of resonance lines in the NMR spectra. A contact shift is observed when the probability of an unpaired electron location in the place of a resonant nucleus differs from zero. Therefore, these shifts constitute a source of information on the nature of the metal-ligand bond as well as on the ligand electronic structure. Pseudo-contact shifts characterise the spatial structure of the molecule, thus being important for solving various structural problems. This paper covers pioneering works describing the specifics of the NMR spectra transformed by adding paramagnetic complexes of iron-group elements on the example of cobalt and nickel complexes, as well as complexes of rare-earth elements on the example of europium. We present main features of the paramagnetic additives method, allowing resolution of difficulties associated with large paramagnetic broadening of resonance lines in high-resolution NMR spectra. Of iron-group elements, a paramagnetic ion Co²⁺ is shown to be an effective shift reagent. In some cases, a Ni²⁺ ion may also be used for this purpose. The paper covers conditions for recording the NMR spectra of samples containing paramagnetic additives; solvents used for this purpose; as well as temperature variations of the studied samples in the context of resonance signal detection. 

The paper analyses complexation of thorium(IV) with 2,3,4-trihydroxy-4’-fluoroazobenzene. A complex is formed immediately after mixing the components. Their molar ratio (1:2) was established using the methods of Starik–Barbanel relative yield, equilibrium shift and isomolar series. The maximum light absorption of the complex is observed at 440 nm, with the molar absorption coefficient being equal to 1.80×10⁴. In this work, we synthesised a new sorbent containing fragments of para-aminosalicylic acid. Identification of sorbents was carried out using IR spectroscopy. Sorption was studied in static and dynamic modes. The optimal conditions for concentration were investigated. The magnitude of the sorption and the degree of metal extraction was calculated from its residual concentration in the solution using a spectrophotometric method. Our results show that the maximum sorption is observed at pH = 4. In the course of preliminary kinetic experiments, it was found that the maximum sorption of cadmium is attained within 2 hours, remaining practically at the same level thereafter. The effect of the ionic strength of the solution was studied using the photometric method. Thorium(IV) was sorbed from solutions having an ionic strength of 0.1–1.4. It is shown that a significant decrease in the sorption of thorium(IV) occurs in solutions with an ionic strength of more than 0.2 M. The effect of metal concentration on sorption was also investigated. An isotherm of thorium sorption by the synthesised sorbent was constructed. An increased concentration of thorium(IV) in the solution leads to an increase in the amount of sorbed metal, with the maximum concentration being reached at 1856 mg/l. We also studied the effect of various acids (HClО₄, H2SО₄, HNО₃, HCl) on the desorption of thorium(IV) from the sorbent: thorium(IV) was quantitatively desorbed by 2 M nitric acid. The degree of extraction of thorium ions (IV) under optimal conditions exceeds 95%. The study has revealed the possibility of using the matrix of a copolymer of maleic anhydride and styrene modified by para-aminosalicylic acid for sorption-photometric determination of thorium(IV). Following regeneration, this sorbent can be reused. 

A comprehensive physico-chemical study of individual systems provides important experimental data, which can be further used both in basic and applied research. Thus, a number of systematic studies have revealed the formation of complex molybdates, which can be classified in terms of cationic composition. Many compounds belonging to this class are shown to possess valuable functional properties. In this work, we set out to generalise and complement the results obtained on phase formation in K2MoO4 – R₂(MoO₄)₃ – Zr(MoO₄)₂ salt systems (R = Al, Cr, Fe, In, Sc, Y, Bi, La –Lu) dependent on the nature of the molybdates of trivalent elements. In addition, we aim to determine synthesis conditions and to characterise properties of these triple molybdates. To this end, methods of X-ray phase analysis, differential scanning calorimetry, electron microscopy and impedance spectroscopy were used. Interaction in ternary salt systems K₂MoO₄ – R₂(MoO₄)₃ – Zr(MoO₄)₂ (R = Al, Cr, Fe, In, Sc, Y, Bi, La – Lu) was studied at subsolidus temperatures across the 723–873 K range. Transformation of phase diagrams was demonstrated; the systems were divided into ten triangulation types. The identified new triple molybdates of the K₅RZr(MoO₄)₆ (R = Al, Cr, Fe, In, Sc, Y, Bi, Dy - Lu) composition were obtained via solid-phase synthesis at temperatures of 723–773 K. Their crystallographic and thermal properties were determined. Molybdates of the K₅RZr(MoO₄)₆ composition are established to crystallize in a hexagonal crystal system and a trigonal crystal system under R = Al, Cr, Fe, In, Sc (space group P63, Z = 2) and under R = Dy - Lu, Y, Bi (space group R`3c, Z = 6), respectively. The electrical conductivity of K₅RZr(MoO₄)₆ (R = Fe, In, Er) was studied using the method of impedance spectroscopy across the temperature range of 300–900 K. It is also demonstrated that the conductivity values of this compound amount to 10^-2 S/cm at 700–850 K.

Benzylidene protecting groups are widely used in carbohydrate chemistry, as a rule, to protect the hydroxyl groups at O-4 and O-6 positions of the carbohydrate residue. With varying degrees of selectivity, 4,6-benzylidene protection allows introduction of other functional groups at O-2 and O-3 positions of sugars and is easily removed from the molecule under acidic conditions. We have previously proposed a scheme for obtaining acyl derivatives of natural glycoside salicin (glycoside of salicylic alcohol) from the intermediate glycoside helicin (glycoside of salicylic aldehyde). The aldehyde group can be reduced to alcohol during the final synthesis stages. Moreover, this group does not require additional protection during the modification of the carbohydrate residue, since it does not participate in acylation reactions, unlike the hydroxymethylene group of salicin. For the temporary protection of O-4 and O-6 hydroxyls of helicin, it was proposed to use a benzylidene protecting group. In this paper, we set out to study the reactivity of helicin in the reaction of 4,6-benzylidene formation, as well as to establish factors affecting such processes. Attempts were undertaken to introduce a benzylidene protecting group into a helicin molecule in two ways: using benzaldehyde dimethyl acetal, as well as using benzaldehyde and zinc chloride. In the former case, the conversion of the original glycoside was not observed, while the second reaction resulted in the product of an unidentified structure. Possible reactions occurring with the reagents applied were modelled using quantum-chemical calculations. It is found that the inability of benzaldehyde dimethyl acetal and benzaldehyde to react on 4,6 hydroxyls of glucose is explained by the competing reaction of the aldehyde group in the structure of helicin. Moreover, the catalysis with zinc chloride most likely produces a helicin dimer. Thus, it is found that benzylidene protection has certain limitations and cannot be applied in the case of glycosides containing aromatic aldehydes as the aglycone part.

Water is the most important component determining the structure and properties of countless elements of animate and inanimate nature. The ability to respond to even the most insignificant external influences makes it a unique object of study. In this work, we studied the effect of the low-intensity electromagnetic field of radio frequency range (f = 100–200 MHz) on the physical and chemical properties of deionized water, which depend on such intermolecular forces as heat, evaporation rate, cohesion, adhesion, etc. At atmospheric pressures, irradiated water is shown to boil at higher temperatures (Tb= 102.0 °С), with the evaporation heat of irradiated water exceeding that of non-irradiated water by 6.5%. At the temperature of 22 °C, irradiated water evaporates more slowly than non-irradiated water and is characterised by higher values of surface tension, work of cohesion and contact angle. In addition, the contact angles of irradiated water on a polystyrene surface increase by 19–23% as compared to that of non-irradiated water. The effectiveness of electromagnetic radiation depends on the frequency and time of exposure. Exposure to field frequencies of 130 MHz and 180 MHz for 1–3 hours caused maximum changes. A further increase in the duration of exposure was ineffective. Irradiated water retained its properties throughout the entire observation period. It is shown that increased cohesive forces reduce the adhesion of irradiated water to the polystyrene surface, thus decreasing its wetting ability. A minimal adhesion of water to a solid surface was observed for water exposed to a field frequency of 130 MHz. The negative values of spreading coefficients, defined as the difference between the work of adhesion and the work of cohesion, indicate that water does not spread over the polystyrene surface. The obtained experimental data prove that exposure to an electromagnetic field strengthens the supramolecular organisation of water, as well as enhances intermolecular interactions in aqueous media. Strengthening of cohesion can lead to a change in the solvation of molecules and ions dissolved in water, as well as to a disruption of their transportation through biological membranes, which affects the functioning of individual cells and the activity of the organism as a whole.

The activity coefficient of individual ions is an important parameter in the theory of strong and weak electrolytes in aqueous and non-aqueous solutions. The physical meaning of the average ion coefficient lies in the ratio of the practical and theoretical activity coefficients. If the activity coefficient is set equal to 1 .0, as in the majority of published works, the final calculations can present multiple distorted γ± results. The activity coefficient constitutes a measure of the deviation of real (practical or experimental) parameters from the ideal ones. Ideal parameters are calculated for dilute solutions of non-electrolytes, in which no interactions are assumed to occur. Activity coefficients in high-concentration solutions may reach the values of several tens. However, some empirical data has indicated the dependence of the activity coefficient of electrolytes on their concentration, with some concentrations showing its minimal values. The coefficients equal to several tens, i.e. describing deviations from ideal parameters by the factor of ten, are difficult to adapt for practical application in solutions where association processes or other intermolecular interactions dominate. The present paper describes a number of methods for estimating the average ionic activity coefficients of such strong acids as hydrochloric, hydrobromic, hydroiodic, perchloric, nitric and sulphuric acids across the concentration range from 1 to 10 mol/l. These methods are based on the concepts of nonlinear programming and the method of multi-level modelling of various properties and parameters applied as a calculation tool. According to the performed calculations, the as-estimated activity coefficients of the acids under study are found to be in good agreement with the literature data for the concentration range from 1 to 10 mol/l.

Hawthorn berries are traditionally used as a medicinal raw material in folk medicine. This plant contains important organic acids and flavonoids, such as carotene, pectin, ascorbic acid, saponins, starch and group B vitamins, which are believed to facilitate the restoration of the cardiovascular system. Medicinal raw materials are primarily used in the form of extracts. In this work, we use three extraction technologies: one conventional technique, i.e. infusion (37 °С, 2 hours), and innovative ones involving the use of microwave (800 W, 1 min) and ultrasonic irradiation (0.5 W, 2 hours). In order to determine the most optimal method for obtaining a complex of substances exhibiting antioxidant properties from hawthorn fruit extracts, we studied the content of dry substances, phenols and flavonoids. In addition, the antioxidant activity was determined by trapping free radicals and using the FRAP method (restoring force). On the basis of the obtained experimental results, the hawthorn fruit extraction conducted using ultrasonic irradiation is found to be the most effective of all the considered technologies, since it yields the highest values for all the studied parameters as compared to other extraction methods. Thus, the following levels were achieved: phenols – 723 mg of gallic acid per 100 g; flavonoids – 194 mg of catechin per 100g; dry substances – 1.68 %; anti-radical activity – 14.5 mg/cm3 ; restoring force – 14.5 mmol of Fe2+ per 1 kg. Our results show that the extraction using microwave irradiation cannot be recommended, since the values obtained using this method are lower than those obtained by ultrasonic irradiation and infusion.

Hawthorn berries are traditionally used as a medicinal raw material in folk medicine. This plant contains important organic acids and flavonoids, such as carotene, pectin, ascorbic acid, saponins, starch and group B vitamins, which are believed to facilitate the restoration of the cardiovascular system. Medicinal raw materials are primarily used in the form of extracts. In this work, we use three extraction technologies: one conventional technique, i.e. infusion (37 °С, 2 hours), and innovative ones involving the use of microwave (800 W, 1 min) and ultrasonic irradiation (0.5 W, 2 hours). In order to determine the most optimal method for obtaining a complex of substances exhibiting antioxidant properties from hawthorn fruit extracts, we studied the content of dry substances, phenols and flavonoids. In addition, the antioxidant activity was determined by trapping free radicals and using the FRAP method (restoring force). On the basis of the obtained experimental results, the hawthorn fruit extraction conducted using ultrasonic irradiation is found to be the most effective of all the considered technologies, since it yields the highest values for all the studied parameters as compared to other extraction methods. Thus, the following levels were achieved: phenols – 723 mg of gallic acid per 100 g; flavonoids – 194 mg of catechin per 100g; dry substances – 1.68 %; anti-radical activity – 14.5 mg/cm3 ; restoring force – 14.5 mmol of Fe2+ per 1 kg. Our results show that the extraction using microwave irradiation cannot be recommended, since the values obtained using this method are lower than those obtained by ultrasonic irradiation and infusion.

The article presents the results of research into the biotechnological processing of collagencontaining raw materials (bovine rumina) to create functional foods. The patterns of biotransformation of collagen-containing raw materials by activated cultures of probiotic microorganisms (Bifidobacterium longum B379 M, Propionibacterium shermanii KM 186 and Lactobacillus helveticus Н17-18) have been studied and theoretically substantiated. It is noted that bovine rumina, following preliminary heat treatment, comprise a good nutrient medium for the development of probiotic cultures. It was revealed that low-molecular compounds formed during the heat treatment of rumina possess prebiotic properties that stimulate the growth of microorganisms. It was established that after 5–8 hours of cultivation, the number of viable cells of the studied cultures in the collagen substrate increases to 10⁹ –10¹⁰ CFU / g. It is noted that the biomodification of rumina improves their organoleptic properties and consistency, causing it to become succulent, soft and ductile. Biotransformation of collagen-containing raw materials by probiotic microorganisms leads to a significant increase in amino acids in hydrolysates in comparison with the control sample. The greatest increase in amino acids is observed during the fermentation of collagen Lactobacillus helveticus H17-18, which indicates a higher proteolytic activity of this culture. It was shown that the rumen microstructure undergoes changes under the action of probiotic microorganisms in comparison with the initial state (the muscle carcass becomes thinner and looser, as well as undergoing change in terms of the structure of its morphological elements). As a result of the research, a fundamentally new scheme of biotechnological processing of collagen-containing raw materials was developed. The obtained results open up broad prospects for the creation of BAA-synbiotics and food products intended for functional nutrition. 

A high demand for bacterial nanocellulose (BNC) in various economic sectors has resulted in intensification of studies aimed at searching for ways of reducing the cost of its production. BNC on an industrial scale is obtained using synthetic nutrient media, the cost of which may amount to 30–60% of the total cost of the process. Therefore, the study of BNC biosynthesis using low-cost nutrient media, such as food and cellulosic waste and other alternative sources of raw materials, seems to be highly relevant. The biomass of miscanthus currently used as a raw material for biofuels may become such an alternative source. Miscanthus is characterised by availability, low cost and annual renewability on an industrial scale. This study was aimed at investigating the BNC biosynthesis process from the enzymatic hydrolyzate obtained by alkaline delignification of miscanthus. The delignification process involved treatment of the plant with a dilute sodium hydroxide solution at ambient pressures. Enzymatic hydrolysis of the obtained substrate was carried out in a 11L-fermenter. For the first time, BNC was successfully obtained in a nutrient medium from an enzymatic hydrolyzate produced by alkaline delignification of miscanthus. The symbiotic culture of Medusomyces gisevii Sa-12 characterised by a high adaptive potential was used as a producer. The maximum specific growth rates were 0.360 and 0.384 day^-1 for yeast and acetic acid bacteria, respectively. Consumption of reducing substances was observed to proceed in two stages: the rate constant of substrate utilisation at the first and the second stages were equal to 0.464 day and 0.034 day^-1, respectively. The highest yield of BNC was 5.14% on the 14th day of cultivation, which is 1.8 times lower than that on a synthetic nutrient medium. Although the nutrient medium of the enzymatic hydrolyzate obtained by alkaline delignification of miscanthus is not biologically pure, Medusomyces gisevii Sa-12 shows a high technological potential and ability to synthesize a chemically pure BNC even under adverse conditions. 

This paper is aimed at developing a technology for obtaining encapsulated forms of biologically active substances exhibiting antioxidant properties from secondary agricultural materials. A technology for ultrasoundassisted extraction of antioxidants followed by their encapsulation was developed. We studied the structural and functional interactions between the structural units of biopolymer capsules using the methods of Fourier transform infrared spectroscopy. The spectrum of alginate capsules containing extract shows a number of differences as compared to those of capsules without extract, which indicates successful inclusion of biologically active plant substances (peak intensity varies within the range of 800–1600 cm-1 , 1240.30 cm-1 and 1512.26 cm-1 ). However, these changes do not suggest any significant chemical interactions between the biopolymers and the encapsulated substance. The results of the developed encapsulated antioxidants in terms of their size, moisture, encapsulation efficiency and yield, extract content, as well as other physico-chemical parameters were similar to each other and in good agreement with literature data. The experiments showed that all of the capsules began to swell to varying degrees in an artificial intestinal tract due to increased electrostatic repulsion forces. The obtained results on the change in mechanical properties of the developed capsules show the degradation of the capsules (with the values of capsule strength tending to zero) to occur with time and under the influence of alkaline conditions and monovalent ion salts. These facts confirm the feasibility of developing encapsulated antioxidant forms from secondary agricultural materials, which can help bridge the deficiency of bioactive substances in the human diet in the bioavailable form.

Detection of the expression levels of the dehydrin gene in plants is increasingly becoming a widespread technique for testing plant resistance to cold, drought, salinity or high heavy metal concentrations in soils. The simplest way to determine the content of dehydrins consists in using specific antibodies (antibody specificity is critical). The experience of dehydrin detection in various plants provided a basis for this work. In this study, we set out to compare the reactions of antibodies with reactive proteins derived from three most accessible sources, as well as to assess their specificity. The comparability of detected proteins in terms of their quantity and molecular weight was studied for several plants: 1) total and thermostable protein in scots pine needles; 2) mitochondrial protein in peas; 3) total and thermostable protein in winter wheat; 4) total and thermostable protein in arabidopsis. In all the cases, either slight or significant differences in the quantity and molecular weight of the detected protein groups were observed. These differences can be attributed to the three possible reasons: K-segment variability; different carrier proteins used by manufacturers; as well as the presence of shared reactive epitopes in some groups of proteins that are not dehydrins. The analysis of differences in the number of the groups detected using antibodies from different manufacturers reveals their amount to be minimal for cereal plants and becoming larger for dicotyledons and conifers. The largest number of the groups was detected in pea mitochondria. Some of the antibody-binding protein groups are definitely not dehydrins. The abovementioned differences are smaller for thermostable proteins. Thus, obtaining a thermostable protein fraction can be recommended as a simple procedure increasing the dehydrins detection level. The comparison of the dehydrin amounts should not be used as a measure of the relative plant resistance when comparing evolutionarily distant species, since the antibody reactivity to the dehydrins of distant species may differ significantly. At the same time, this method can be used in agrobiology for the molecular-level assessment of the initial or induced resistance of plant varieties (same or related species) to cold, drought, as well as other adverse conditions associated with water deficiency.

This paper presents data on cloning, heterogeneous expression and characterization of recombinant homologs of a DNA-binding protein contained in the Thermotoga naphthophila (TnaDBP, TnaDBP-mut) hyperthermophilic microorganism. Initially, the nucleotide sequence of the original thermostable TnaDBP protein was subjected to codon optimisation in accordance with the structural and operational features of the nucleic acid metabolism system of the Escherichia coli mesophilic bacterium subsequently used as a laboratory strain-producer. Expression vector constructs were designed to ensure efficient production of TnaDBP and TnaDBP-mut proteins in E. coli cells. Optimal conditions for the cultivation of transformed strains for the biosynthesis of the soluble form of the target protein product were selected. A trial aerobic cultivation of the microorganisms was carried out under controlled conditions. Specific features of the growth kine - tics for transformed E. coli BL21 (DE3) [pET-TnaDBP-mut] cells were studied. It shown that, under cultivation in a liquid nutrient medium, the E. coli BL21 (DE3) [pET-TnaDBP-mut] culture producing the mutant DNA-binding protein reaches the stationary growth phase 10 hours after the inducer has been administered. A scheme consisting of a few stages is proposed for purifying the obtained proteins using thermolysis. A preliminary assessment of the solubility and thermal stability of the protein according to its primary amino acid sequence was carried out. Possibilities for the practical application of recombinant variants of the thermostable TnaDBP DNA binding protein are considered. Our results evidently demo nstrate that such proteins, due to their unique physicochemical properties, present great interest from a biotechnological point of view and can be used in various industries as sources of essential L -amino acids for cultures of eukaryotic cells as a basis for enteral nutrition of farm animals, as well as a necessary component base in the development of non-viral vector systems and carrier proteins in the field of biomedicine and fundamental science.

This article compares conventional (FeCl₃, Al₂(SO₄)₃) and innovative (Biokat P 500 и Nanofloc) reagents used in the combined biological and chemical wastewater treatment for coagulating medium components and microbial suspensions. In this study, we aimed to assess the effect of these reagents on the quantitative and species composition of microorganisms present in activated sludge. To that end, we modelled the processes of the combined biological and chemical wastewater treatment; cultivated samples of activated sludge and transferred them to selective media in order to establish the number of different physiological groups of microorganisms; as well as determined the taxonomic identity of bacterial colonies (nitrogen-fixing and phosphate-mobilizing bacteria). Changes in the biocoenosis of activated sludge were assessed for such agronomically important groups of microorganisms as diazotrophs, phosphate-mobilizing bacteria, actinobacteria, micromycetes, etc. It is established that combined biological and chemical wastewater treatment in most cases leads to a decrease in the number of these microorganisms. A notable decrease in the number of microorganisms in activated sludge samples containing a conventional reagent Al₂(SO₄)₃ is experimentally confirmed. FeCl3 is shown to be the second most effective reagent in this respect. It is demonstrated that Nanofloc, despite inhibiting many studied groups of microorganisms, contributes to an increase in the number of diazotrophs; whereas the use of Biokat P 500 leads to the least negative consequences in terms of the number and composition of microorganisms present in activated sludge. In the course of identifying predominant nitrogen-fixing and phosphate-mobilizing bacteria via proteomic analysis, it is established that the following bacterial cultures are present in the control sample: Klebsiella oxytoca, Pseudomonas putida, Acinetobacter johnsonii, Rhodococcus erythropolis. These microorganisms are known for playing a significant role in ecology and biotechnology. Following addition of FeCl3 to the test samples, only one bacterial culture (K. oxytoca) was found to be predominant; whereas addition of innovative reagents resulted in two predominant bacterial cultures (Biokat P 500 – Enterobacter ludwigii and Aeromonas veronii; Nanofloc – Enterobacter cloacae and R. erythropolis). The presence of several dominant bacterial species, belonging to other groups than nitrogen-fixing or phosphate-mobilizing bacteria, may indicate the syntrophic nature of activated sludge communities. 

Petroleum and coal pitches are known to be among the most important sources of raw materials for the production of carbon materials, including electro-carbon, heat- and chemical-resistant structural products, metal-carbon and carbon-carbon composite materials, graphite electrodes, self-baking anode paste, carbon fibres, blast furnace and cupola coke. The quality of the pitches is determined by the elemental and group composition, as well as their structural and physical-chemical properties. The study of the molecular structure and group composition of the organic components of the pitch and the identification of the effect of the composition on the performance of the products is of great interest for assessing the prediction of the behaviour of pitches during processing and the properties of the products obtained from them. The present work is devoted to the study of the group composition of two petroleum and two coal pitches using high-resolution NMR spectroscopy. The data of the ¹H and ¹³C NMR spectra allow the composition of the pitch product to be estimated without separation into fractions, which, in turn, combined with the accuracy of the method and the recording speed of the ¹H NMR spectra, increases the rapidity of this method of analysis. The combination of ¹N and ¹³C NMR data allows additional information on the correlation of physical parameters and pitch composition to be established. The calculation of the (H_ar/H_al) parameter, corresponding to the ratio of the integral intensities of signals of aromatic and aliphatic hydrogen atoms, provides the possibility of using it as a structural characteristic for a particular sample. In order to ensure the correct contribution to the integral intensity of the signals, ¹³C NMR spectra were recorded in a pulse sequence with suppression of the spin-spin proton interaction only for the period of data reading for the purposes of minimising the nuclear Overhauser effect. The relaxation delay between pulses was set to 10 s. The study of petroleum and coal pitches using NMR spectroscopy showed the proton spectra of NMR data to be sufficiently informative and suitable for monitoring the technological process of pitch production.

A large number of different packing elements are applied in the chemical, oil refining, petrochemical, food and other industries for implementing heat-and-mass transfer processes in columns. The advantage of packed columns consists in their high efficiency, low flow resistance and stable operation. The most important requirements for packing elements include their high specific surface area, large free volume proportion, ease of manufacture and low material consumption. However, few available packing elements meet all of the aforementioned requirements. In this work, we developed a helical packing element for implementing heat-and-mass transfer processes in distillation, absorption and extraction columns, as well as in cooling towers, and carried out a series of respective hydraulic tests. The novel packing element is characterized by a simple design, implying coiling a metal strip into a helix. Such a shape excludes the contact with neighbouring elements, which prevents blocking of the packing surface and formation of stagnant zones. A specific feature of this design consists in the smooth surface of the element, which prevents the formation of drops and streams, thus reducing the mass transfer efficiency. The film-like flow through the packing element ensures high mass transfer characteristics with minimum entrainment, thus contributing to the reduction of flow resistance. On the basis of experimental data, empirical equations were obtained for calculating the flow resistance of dry and wet packing patterns. A comparative analysis of the developed packing element with Pall Rings and Inzhekhim-2000 is provided. It is shown that the developed helical packing element is characterized by a large surface area, significant free volume and low flow resistance. In addition, the simple design of the element significantly reduces its production costs.

In order to increase the yield of light oil products, it is proposed to use the following heavy fractions obtained by JSC Angarsk Petrochemical Company in the course of oil refining as components for lowviscosity marine fuel: light coker gas oil, heavy diesel fractions removed from vacuum columns of primary-oilrefining units, heavy diesel fractions obtained from atmospheric columns and vacuum distillates of various fractional compositions. The results of tests conducted according to standardised procedures showed that an introduction of depressor (VES-410D) and depressor-dispersing (VES-410DDP) additives into the components of low-viscosity marine fuel significantly depresses the pour points of these components. In this article, the authors propose depressor and depressor-dispersing additives, as well as determine their optimal concentrations for high depression rates allowing the pour point to be reduced to a standardised value for the compound composition using heavy diesel fractions of primary and secondary refining processes. In addition, the authors determined the optimal basic formulation of the low-viscosity marine fuel including products of primary and secondary oil processing with heavy fractional composition. A number of commercial depressordispersing additives were tested using this basic formulation in order to explore alternatives and study the additives market. Five of these commercial additives provide good chemmotological indicators for lowviscosity marine fuel (including low-temperature characteristics, filterability and sedimentation stability) and can be recommended for further industrial use. The optimal composition of the mixtures was modelled on the basis of the obtained data, allowing a determination of the most rational technology for producing low-viscosity marine fuel in conformity with regulatory requirements.

An increased fire hazard of lignite drives the need to study its propensity to self-combust resulting from possible self-heating, which eventually leads to its ignition. Coals formed by low-grade metamorphism are subject to these dangerous processes to a greater degree. Availability, large reserves and low cost of these natural coals, as well as appropriate physical and chemical properties make them indispensable in carbon activation. Activated carbons, in turn, are employed for carrying out various processes in hydrometallurgy; for removing impurities of inorganic and organic origin from industrial wastewater; for purifying industrial gases. Moreover, activated carbons are used in medicine and other economic sectors. In this study, we determined the kinetic parameters characterising the fire hazard associated with spontaneous combustion of lignite during its treatment in the course of carbon activation. Lignite from a well-known large Irsha-Borodino deposit of the Kansk-Achinsk basin was selected as the object of study. Dispersity was chosen as the main physico-chemical parameter, since its value has a significant impact on the creation of hazardous conditions for self-heating of dispersed materials. In order to choose a research procedure, an analysis of known methods for evaluating the propensity of dispersed substances to spontaneous combustion was performed. Spontaneous combustion of lignite was studied using an improved method of calorimetry, allowing investigation of this process in terms of materials dispersity. The rate of heat release during spontaneous combustion of lignite, as well as the main kinetic parameters (effective activation energy and pre-exponential factor), were determined. The obtained values of the kinetic parameters show that a decrease in the dispersity and consolidation of crushed lignite particles (Irsha-Borodino deposit, Kansk-Achinsk basin) significantly raises the propensity of these coals to self-heating and eventual spontaneous combustion. The obtained results can be used for developing measures aimed at reducing the fire hazard involved in lignite processing technologies employed in the course of carbon activation. Compliance with specific recommendations on controlling the self-heating process and resulting spontaneous combustion can be achieved by forecasting conditions for the increase of coal temperature through controlling kinetic parameters.

This article describes the formation of an effective sorbent for heavy metal ions by modifying natural zeolite (clinoptilolite type, Kholinskoye deposit). The modification was carried out by applying the network of a sulphur-containing polymer on the zeolite surface. For the formation of a polymer network, elemental sulphur was dissolved in the hydrasine hydrate–monoethanolamine system to generate polysulphide anions (in particular, S2^2-). During the contact of the obtained sulphur solution with zeolite, polysulphide anions and the monoethanolamine entering the zeolite pores were concentrated on the surface. Further polycondensation of S2^2- anions with 1,2,3-trichloropropane (epichlorohydrine production waste) resulted in the formation of a reticulated sulphur-containing polymer covering the zeolite surface. Such a sorbent provides immediate solution to the problems concerned with utilisation of organochlorine wastes and purification of technological media containing heavy metals. Extraction of metals by the obtained sorbent was studied using model solutions with a metal concentration of 5000 mg/L. Encouraging results were obtained for five metals. Detailed information on the extraction of copper ions from aqueous solutions is presented. Experimental data was obtained on the effect of pH on the sorption efficiency of copper ions, as well as on the thermodynamic and kinetic characteristics of adsorption under static and dynamic conditions. The complex coordination mechanism of Cu (II) sorption by modified zeolite was confirmed using IR-spectroscopy. Since the thermodynamic and kinetic dependencies frequently deviate from the classical laws during sorption by the complex coordination mechanism, regression analysis was used to process the experimental data. As the result, nonlinear models were obtained fairly accurately describing experimental data on the extraction of copper ions by modified zeolite. The obtained regression models can be applied in further research of the new sorbent and in designing installations for extracting copper compounds from technological media.