The development of new preparations for managing skin lesions is a task requiring a complex research approach. Thus, one promising direction consists in the creation of new bases for wound-healing drugs for external application. Chemical compounds that can be used as such bases include polymeric hydrogels, representing spatially cross-linked macromolecules that swell in a solvent. This property provides an opportunity to load hydrogels with drugs of both synthetic and herbal origin. A search for a gel-forming polymer acting not only as a drug carrier, but also as a healing agent presents a relevant research task. In a previous work, the authors obtained polyhexamethylene guanidine hydrochloride hydrogels by crosslinking terminal amino groups with formaldehyde. The conducted studies of the wound-healing capacity of the obtained hydrogels and compositions on their basis confirmed their comparability with such widely-used agents, as levomecol, bepanthene, etc. In addition, the obtained compositions were found to exhibit their own activity. Therefore, hydrogels based on polyhexamethylene guanidine hydrochloride can be used as a promising platform for drug design. In this work, the destruction products released during hydrolysis of the hydrogel under study were investigated. IR and UV spectroscopy methods were applied to evaluate the concentration of hydrogel destruction products over time. A mechanism of hydrogel destruction yielding the initial polyhexamethylene guanidine hydrochloride and formaldehyde in a gem-diol form is proposed.

Hydrogen as a versatile energy carrier continues to attract research attention in the field of applied chemistry. One of the fundamental issues on the way to hydrogen economy is the difficulty of hydrogen storage. Physical adsorption of hydrogen in pores is a feasible and effective method of hydrogen storage. Among existing hydrogen-adsorbing materials, carbon nanostructures possess a number of advantages due to their high adsorption capacity, significant strength and low weight. In this work, we use the modern methods of quantum chemistry (DFT, SAPT0 and IGM) to study the adsorption of molecular hydrogen in a series of simulated slit-like carbon micropores with a distance between the walls of d = 4–10 Å, including the introduction of an H₂ molecule into a pore, filling pores with these molecules and investigating the interactions between H₂ molecules inside the pores. It was found that, depending on the value of parameter d, adsorbed hydrogen molecules form one (d = 6, 7 Å) or two layers (d = 8, 9, 10 Å) inside the pore. At the same time, for pores with small d values, high potential barriers to the introduction of H₂ into a pore were observed. The decomposition of the interaction energy into components showed dispersion interactions to make a major contribution to the energy of attraction (72–82%). Moreover, an increase in the number of H₂ molecules adsorbed in the pore decreases the significance of dispersion interactions (up to 61%) and increases the contribution of electrostatic and induction interactions to intermolecular attraction. Gravimetric density (GD) values were determined for pores with d = 6, 7, 8, 9, 10 Å, comprising 1.98, 2.30, 2.93, 3.25 and 4.49 wt%, respectively. It is assumed that the revealed peculiarities of hydrogen adsorption in pores will contribute to the use of carbon porous structures as a medium for hydrogen storage.

Along with synthetic substances, various naturally-occurring pigments can response to pH variations in solutions by changing their colour. Such substances include, for example, anthocyanins. In this study, the possibility of applying a set of anthocyanins obtained from berry extracts as a potential acid-base indicator. This indicator can be a good alternative to the widely-used phenolphthalein test. Aqueous and alcoholic extracts derived from the fruit of ashberry, sea-buckthorn, lingonberry, blueberry, currant, blackberry, cranberry, rose hip, cherry and hawthorn plants were studied. The presence of anthocyanins in the test samples was confirmed by chemical and physicochemical methods of analysis, including qualitative tests, ascending thin-layer chromatography and direct spectrophotometry. Quantification of anthocyanins was carried out by pH-differential spectrophotometry. Compared to alcoholic extracts, aqueous berry extracts were found to contain anthocyanins in far lesser amounts. In order to compare the pH indicator potential of phenolphthalein and the studied set of anthocyanins, the content of ascorbic acid in the test samples was assessed by direct alkalimetry. A control experiment was performed using a 5% ascorbic acid solution for injection. The pH value of aqueous and alcoholic solutions of all berry extracts was determined by an instrumental procedure. The pH of the extracts ranged from 2.95 to 5.04. The content of the total amount of anthocyanins in aqueous and alcoholic extracts of blackberries, cranberries, black currants, blueberries and lingonberries in terms of cyanidin-3-glucoside was determined both quantitatively and qualitatively. A good agreement was achieved between the results of alkalimetric titration performed using phenolphthalein and the set of anthocyanins extracted from blackcurrant berries with 95% ethanol.

The processing of plant biomass into demanded and economically viable products is currently a recognized global trend. Among alternative energy directions, biomass conversion is the most predictable and sustainable carbon resource that can replace fossil fuels. Already today, plant biomass provides almost 25% of the world’s energy supply. This review provides information on the most promising areas of chemical and biotechnological processing of the biomass of such an energy plant as miscanthus. The choice of miscanthus is due to its high yield (up to 40 t/ha of sown area) and high energy yield (140–560 GJ/ha) compared to other plant materials. In addition, miscanthus is able to grow on marginal lands and does not require special agronomic measures, while in the process of its cultivation, the soil is enriched with organic substances and it is cleaned from pollutants. The review reflects the directions of processing of native biomass and pretreated biomass. Miscanthus biomass, in addition to processing into energy resources, can be fractionated and transformed into many high-value products - cellulose, cellulose nitrates, ethylene, hydroxymethylfurfural, furfural, phenols, ethylene glycol, cooking solutions after nitric acid pretreatment of miscanthus biomass can act as lignohumic fertilizers. In addition, on the basis of miscanthus cellulose hydrolysates, it is possible to obtain benign nutrient media for biotechnological transformation into bacterial nanocellulose, for the accumulation and isolation of various microbial enzymes.

Substances that have a harmful effect on living organisms include N-phenyl-2-naphthalamine and phthalates, which are synthesized and widely used in the chemical industry. At the same time, N-phenyl-2-naphthylamine was found in the aerial parts and in the roots of some plant species, phthalates were found in many plant species and in bacteria. The aim of this research was to study the protective (antimicrobial) reaction of pea (Pisum sativum L.) seedlings of the Torsdag variety to the inoculation with bacteria Rhizobium leguminosarum bv. viceae (endosymbiont) and Azotobacter chroococcum (ectosymbiont) introduced into the aqueous medium of root growth were studied. Changes in the content of negative allelopathic compounds (pisatin, N-phenyl-2-naphthylamine, phthalates) in root exudates were the reaction indicators. After the inoculation, the seedlings grew for 24 h in the BINDER KBW-240 chamber at 21 °C, with lighting of 81 μM.m^-2 . sec^-1 and a 16/8 h day/night photoperiod. In ethyl acetate extracts from the aqueous medium where the seedling roots were immersed, the content of the compounds was determined by HPLC, while changes in the composition and ratio of phthalates were determined by GC-MS. Data indicating the different ability of both bacterial species to degrade N-phenyl-2-naphthylamine to phthalates and the dependence of this process activity in the bacteria studied on its concentration in the medium were presented. N-phenyl-2-naphthylamine differently but negatively affected the viability and growth of the bacteria used in the experiments. A different effect of rhizobia and azotobacter on the content of the above named compounds and on the ratio of types of phthalates in root exudates was elicited.

Bacteria most commonly exist in nature in the form of bacterial biofilms, i.e. associations of cells attached to a substrate surrounded by a polymer matrix. Research into biofilm formation and functioning is fundamental to the management of microbial associations in ecology, biotechnology and medicine. This task requires the development of analytical approaches capable of providing timely information throughout the life cycle of microbial communities at the same time as maintaining their intact structure. In this paper, we apply scanning electron microscopy and IR spectroscopy as rapid methods for analysing microbial biofilms. To this end, the growth kinetics of a Bacillus subtilis culture cultivated on a solid substrate for 24 h was comparatively studied by the methods of classical microbiology and biochemistry, electron scanning microscopy and Fourier-transform IR spectroscopy. The biofilm morphology was found to vary from a uniform settlement of planktonic cells over the substrate surface at the initial stage of growth (6 h) followed by the accumulation of the extracellular matrix and the formation of microcolonies at the exponential and stationary stage (12–18 h) and a gradual depletion of the matrix at the stage of cell death (24 h). The results of IR spectroscopy were established to agree well with those of biochemical studies, thereby demonstrating the potential of the method for a timely evaluation of the accumulation of proteins, polysaccharides and nucleic acids and for obtaining information about their structural state in the studied biofilm. It is concluded that scanning electron microscopy and Fourier-transform IR spectroscopy can be used for obtaining complementary information about the morphology and chemical composition of microbial biofilms during their cultivation.

The paper examines the growth of Trichoderma spp. strains and their interaction at different temperatures. Trichoderma spp. is a genus of microscopic ascomycetes; these fungi belong to different ecosystems and are found in soil (rhizosphere). The study aims to analyze and compare the characteristics pertaining to the growth of Trichoderma species and the interaction between them. The experiments used the following media: a Czapek medium and a medium simulating plant root exudates (Cucumis sativus). The growth rate of Trichoderma spp. strains was determined at different temperatures. The use of a medium containing plant exudate models provided a different growth rate as compared to that obtained when using a rich growth medium; some variations in the macromorphology of colonies were also observed. The growth of Trichoderma longibrachiatum F2124 and Trichoderma viride F2001 strains was detected at 9 °С on the Czapek medium, while only the Trichoderma longibrachiatum F2124 strain was observed to grow on the medium simulating exudates. A significant growth inhibition was noted at 40 °С for all strains, except for Trichoderma longibrachiatum species. No colony growth was observed at 50 °С. All the strains grew within the temperature range of 12 to 28 °С. It was assumed that Trichoderma species growing in various media may interact differently with each other. Interaction between the three strains of Trichoderma spp. was examined via the surface culture method under different temperature conditions. The study found no significant differences in the interaction between the Trichoderma species.

It is widely believed that phthalates are xenobiotic pollutants whose prevalence in the environment is associated with their facilitated diffusion from plastic materials. Studies into the effect of synthetic phthalates on living organisms revealed their extremely negative action on the metabolism of animals and humans. The acting mechanism of these compounds is realised through a ligand-receptor pathway. Along with dioxins, polychlorinated biphenyls and similar compounds, phthalates are classified as endocrine disrupters. However, at present, sufficient evidence has been accumulated confirming the natural origin of phthalates. Thus, phthalates were de novo biosynthesised from labelled precursors in an algae culture. These compounds were detected in closed experimental systems, including cell cultures of highest plants, as well as those isolated from a number of bacterial, fungi, lowest and highest plant forms located far from the sources of technogenic pollution. The concept of phthalate biogenesis assumes the action of these compounds on living systems. Phthalates exhibit bactericidal and fungicidal action and compose allelopathic exudates, suppressing the growth of competing plant forms. Phthalates possess insecticidal and repellent properties. An analogy can be traced between the action of phthalates and endocrine disrupters of another chemical category, namely phytoestrogens, which regulate herbivorous mammal populations. A hypothesis is proposed about the biological role of endogenous plant phthalates representing secondary metabolic compounds. Exhibiting predominantly a shielding function, these compounds participate in the network of interactions between plants, animals, fungi and microorganisms. It should be noted that synthetic and endogenous phthalates are characterised by essential stereochemical differences, which can explain their different action on living organisms.

Natural zeolites are effectively used as fertilizers, substrates, and pesticide carriers, as well as sorbents in the remediation of contaminated soils. Since nanostructured minerals exhibit unique physicochemical properties, they must be tested for toxicity and genotoxicity prior to their use in practice. The mutagenic and antimutagenic properties of a nanostructured water-zeolite suspension were first tested using two bacterial test systems: Ames test and SOS-lux test. According to the obtained data, the nanostructured water-zeolite suspension exhibits no mutagenic activity within the analyzed concentration range (0.75–400 µg/mL). In order to assess the antimutagenic activity of the nanostructured water-zeolite suspension, different types of mutagens were selected: mitomycin C, ethyl methanesulfonate, 2,4-dinitrophenylhydrazine, as well as DNA-damaging agents (ofloxacin and hydrogen peroxide). A significant antimutagenic effect of the nanostructured water-zeolite suspension at 200 μg/mL was shown against mitomycin C in the SOS-lux test (50.0% inhibition of mutagenic activity) and 2,4-dinitrophenylhydrazine in the Ames test (62.0% inhibition). For the other mutagens, a weak antimutagenic effect was observed (17.0% for ethyl methanesulfonate), while no antimutagenic effect was reported for ofloxacin and hydrogen peroxide. These differences can be attributed to the negative charge in zeolites, meaning that they can capture only positive (or neutral) molecules. Therefore, the antimutagenic effect of the nanostructured water-zeolite suspension depends on the charge of the mutagen molecule. According to the obtained results, the nanostructured water-zeolite suspension can be considered environmentally friendly, which allows it to be used for agro-industrial purposes as a fertilizer in the production of crops.

Due to the microbiological resistance of epoxy resins, their disposal after the completion of their lifecycle is a pressing issue. In this respect, the use of biodegradable rice and buckwheat husk derivatives as fillers may improve the service properties of epoxy materials. The results indicate that rice and buckwheat husks, as well as their ashes, can be used by soil microorganisms as a substrate. Compared to buckwheat husks, rice husks increase the biological activity of soil microbiota to a much greater extent. However, compared to rice husks, an increase in the temperature of obtaining rice husk ash leads to a decrease in its use by soil microorganisms as a substrate. This is associated with a decreased content of the X-ray amorphous phase and an increased amount of crystalline minerals in the composition of rice husk ash. At the same time, regardless of the temperature of its production, buckwheat husk ash outperforms buckwheat husks in terms of activated soil respiration, which indicates the possibility of microbiological disposal of buckwheat husk ash during its incubation in a soil. Epoxy materials, both unfilled and filled with rice and buckwheat husk ash, are not used by soil microorganisms as a substrate. At the same time, the filling of epoxy materials with rice husks leads to an improvement in their biodegradability. The biodegradation degree of rice and buckwheat husks, as well as their ashes, determines the effect of these fillers on soil respiration in the presence of epoxy materials.

The chemical stability of fuels is one of the key factors in ensuring the proper operation of combustion engines. Progressive destruction of components of diesel-biodiesel fuels during storage and transportation can adversely affect their physical and chemical parameters. Besides, the destruction of petroleum products under sunlight and the formation of toxic compounds have ecological importance. The purpose of the presented work is to investigate the influence of UV irradiation (λ = 300–450 nm) on the chemical content of petroleum diesel and B5, B10, B20, B50, and B100 fuel blends for the 24 h. As biodiesel, the product of transesterification of non-edible Alhagi oil with methanol was used. Chemical changes after irradiation were controlled by the BRUKER FT NMR spectrometer. The relationship between changes in the chemical composition and important physicochemical parameters (density, viscosity, flash point, and cetane index), before and after photochemical destructions was discussed. Based on the obtained results, it was determined that the B20 fuel mixture has more chemical stability after UV irradiation than conventional diesel and other diesel-biodiesel mixtures.

The main purpose of this study is to investigate the thermal stability and the mechanism of thermal decomposition of Mogoin gol coal, the possibility of liquefaction by pyrolysis and thermolysis, and the possibility of enriching by heavy liquids to reduce the mineral content of coal and improve its quality. Under this purpose, the Mogoin gol coal was characterized by proximate and ultimate analysis, thermogravimetry, and investigated its thermal decomposition (thermolysis and pyrolysis). Thermogravimetric analysis was performed using Japanese HITACHI TG/DTA7300 instrument and pyrolysis investigation was carried out at different heating temperatures 200–700 °C with constant heating rate 20 °C/min for 80 min. On the basis of proximate and elemental analysis results, it has been indicated that the Mogoin gol coal is high-rank coking coal. The pyrolysis of Mogoin gol coal was studied by SNOL furnace at different heating temperatures and obtained from pyrolysis products such as hard residue, tar, pyrolytic water, and gas. From pyrolysis, the yield of pyrolysis tar (6.28 %) was highest at 700 °C. The experiment of thermal decomposition (thermolysis) was carried out in air closed autoclave at 350–450 °C and using hydrogen donor solvent (tetraline) with different mass ratios of coal and solvent (1:1.75; 1:1.5). In the thermolysis experiment, the yield of liquid product is highest with the coal-solvent ratio of 1: 1.5 at 450 °C.

The paper studies how the nature of the plasticizer affects the properties of polymer-bitumen compositions using the fluorescence microscopy. The current petroleum road bitumen used for the construction of road, bridge, and airfield pavements does not meet the requirements for cracking/heat resistance, elasticity, and adhesion to the mineral material surface. Pavement performance characteristics can be significantly improved by introducing thermoplastic elastomers, plasticizers, and surfactants into the composition of petroleum road bitumen. The best results were obtained when using a block copolymer of styrene and butadiene, industrial oil, and cationic surfactant on the basis of polyaminoamides and polyaminoimidazolines. The choice of industrial oil as a plasticizer is attributed to its good compatibility with bitumen and polymer, as well as its high flash point (200 °С). The content of paraffin-naphthenic hydrocarbons in industrial oil is over 70%. Although industrial oil is produced in large quantities, an acute shortage of this petrochemical product is observed due to its wide application; thus, intensive studies are underway to replace industrial oil in the composition of the polymer-bitumen binder. It is proposed to use heavy gas oil produced via catalytic cracking and delayed coking, heavy pyrolysis tar, solvent-extracted oil, and tall oil as plasticizers in the creation of the polymer-bitumen binder. In this connection, the effect of proposed plasticizers on the colloidal structure of the polymer-bitumen binder was studied using the method of fluorescence microscopy. Initial polymer-bitumen binders were produced at ANHK (Angarsk) according to GOST R 52056-2003 Polymer-Bitumen Road Binders Based on Styrene-Butadiene-Styrene-Type Block Polymers. The group composition of the plasticizers under study was determined. It was shown that in order to obtain a polymer-bitumen binder resistant to stratification, plasticizers having a content of aromatic compounds of over 60% are required.

Biosynthetically-produced Pseudomonas poly-3-hydroxyalkanoates (PHAs) are a promising substitute for conventional plastics. Costs involved with the production of PHAs can be reduced by optimizing power consumption, which can be achieved using nutrient media without preliminary steam sterilization. Cultivation of Pseudomonas bacteria resistant to sodium dodecyl sulfate (SDS) on SDS-containing non-sterile media yields a biomass consisting predominantly of a PHA producer. SDS plays the role of an antimicrobial agent that inhibits the growth of foreign microorganisms. In this work, an SDS-resistant culture of Pseudomonas helmanticensis and media containing glycerol and SDS were used. The concentrations of carbon (glycerol) and nitrogen sources were optimized using an experiment performed according to a central composite rotatable design. The concentration of substrate C and the C/N ratio between the glycerol and nitrogen content were varied. The dependence of the degree of substrate conversion in PHA on C and C/N was derived in the R programming environment. The constructed model adequately describes the experimental data at a significance level of 0.05 (adequacy variance of the regression equation 4.1×10^-2; R² =0.98). According to the constructed model, the conversion of glycerol to PHA equals 6.9±0.4%. Under optimized conditions (0.61 g/L nitrogen source; 8.4 g/L glycerol; 96 h), P. helmanticensis converts 7.0% of the substrate to PHA with an average monomer unit length. Using a 16S rRNA metagenomic assay, the proportion of foreign bacteria in P. helmanticensis cultures on non-sterile media containing 0.5 g/L SDS was shown to be 2%.

In order to manage field crop production, reduce the negative impact of abiotic factors, and increase productivity and product quality, the modern agricultural industry uses chemical compounds analogous to endogenous phytohormones. Some of these substances are physiologically valuable due to their capability to improve the resistance of plants to adverse environmental factors. The increased interest in such preparations can be attributed to their low cost and effectiveness at low concentrations. The effect of a protatrane mixture (a, b, c) on changes in the physiological parameters (growth characteristics; water status) of spring wheat (Triticum aestivum L.) was studied at low concentrations (10⁻⁶ and 10⁻⁹ g/L) under chloride salinity conditions. The plants were grown under laboratory conditions in a CLF PlantClimatics chamber, in which untreated and chemically treated spring wheat seeds were evaluated for changes in morphological and physiological parameters under salt stress conditions (150 mM NaCl). The analysis of obtained data revealed that protatranes have a positive effect on the morphometric parameters and water status of plants under chloride salinity conditions. Thus, the examined substances decrease the inhibition of growth processes under chloride salinity conditions. The treatment of seeds with the studied substances increases the tissue water content while decreasing the osmotic potential drop in leaves and roots. Irrespective of the mix ratio, protatranes help to improve the plant water status and mitigate the negative effects of chloride salinity on plant growth.