The acidity parameters and type of functional groups of the aminocarboxylate polyampholyte with prevailing carboxylate groups prepared from an industrial polyacrylonitrile fiber (Panion-110), have been determined. An algorithm for determining the type of functional groups based on the potentiometric titration data at different concentrations of the background electrolyte, has been proposed. Titration curves were calculated for the background electrolyte concentrations corresponding to soil and nutrient solutions for plants. It has been concluded that the ion exchanger is suitable as a component of the ion exchanging fibrous substrate for plants, carrying potassium ions.

The nanoparticles of (Mg, Zn)_xFe_3–xO₄ (x ≤ 0.3) solid solutions have been prepared by coprecipitation with Na₂CO₃ from solutions of salts. For a number of compositions (Mg_0,1Fe_2,9O₄, Mg_0,05Zn_0,1Fe_2,85O₄, Zn_0,18Fe_2,82O₄), an increase of saturation magnetization has been detected, as compared to non-substituted magnetite (MS = 64 emu/g). This can be explained by the tendency of zinc and small amounts of magnesium ions to occupy preferentially tetrahedral sites of the magnetite lattice. In the case of zinc and magnesium joint substitution in the (Mg, Zn)_xFe_3–xO₄ system up to x = 0.3, the values of saturation magnetization decrease slightly comparing to that of magnetite, but remain constant (MS ≈ 58 emu/g). By ultrasound assisted dispersion of nanopowders into polyelectrolyte aqueous solutions, colloidal solutions of non-agglomerated nanoparticles have been prepared. Тhe nanoparticles modified with a layer of positively charged polyelectrolyte demonstrate the best sedimentation stability up to 45 days. Their hydrodynamic diameter is lower than 200 nm, with predominance of the fraction with the size of 40–80 nm.

Stability of water dispersions of a polyorganosiloxane and TiO₂ or mica both in presence of surfactants and without them has been studied at pH 6.7 and 8.7 by nephelometry and granulometry. Aggregate stability of latex-TiO₂ system increases with disperse phase concentration, while decreasing for the latex-mica system. Introduction of anionic and nonionic surfactants into mixed dispersions (pH 6.7) leads to increase. Increase of dispersant pH significantly improves dispersancy of powders in the latex without dispersing agent. 

The effect of anionic surfactant alkyl chain structure on the processes occurring at oil–surfactant solution interface and structure formation in water solution, has been studied. The criteria for evaluating anionic surfactants҆ efficiency have been formulated. It has established that their behavior at the oil–water interface is governed not only by the linearity and saturation of the alkyl group, but also by its length and presence of aromatic ring in its structure. The regularities found are in agreement with the data on the ability of anionic surfactant solutions to wash off oil from metal surface, structural and rheological properties of their water solutions. It has been shown that anionic surfactants effectively reduce the interfacial tension at the oil – water and stabilize the drops of oil thus improving the processes of recovery, preparation and transportation of heavy oil.

The relationship between the temperature of silicic acid gel deposition and the structure of silica formed, has been studied. It has been shown that, with increasing deposition temperature of silicic acid gel, structural parameters of silica samples obtained change greatly. The mechanism of structure formation has been considered and the main causes responsible for this process have been identified. It has been found that with increasing concentration of sodium silicate solution at constant precipitation temperature, the sorption capacity of samples increases while the specific surface area decreases. It has been shown that treatment of washed silica gel in boiling water improves its adsorption capacity and reduces its specific surface.

The membrane composition of molybdate-selective electrodes based on higher quaternary ammonium salts (QAS) has been optimized. It has been found that electrodes with the best analytical characteristics are based on 2,3,4-tris(dodecyloxy) benzyltrimethylammonium bromide (TM), with 4-trifluoroacetylbenzoic acid heptyl ester (HE) as the solvating additive. Their analytical characteristics, such as lower detection limits (5·¹⁰⁻⁶mol/l); selectivity coefficients to interfering chloride (2·¹⁰⁻³), sulfate (9·¹⁰⁻³), oxalate (2·10−2) and tungstate (5·¹⁰⁻³) ions; working pH range (7.5−8.5); and the slope of the electrode function (28 mV/pC) have been determined. Sodium molybdate aqueous solutions have been studied with FT-IR spectrometry method at various pH, and it has been shown that at pH above 7.5 hydrolysis is not significant. However, for molybdateselective electrodes it is better to use freshly prepared solutions, as it increases the reproducibility of the experimental results. 

Method for determination of 69 pesticides from different classes (amides, anilinopyrimidines, dinitroanilines, imidazoles, carbamates, carbanilates, morpholines, neonicotinoids, organodithiophosphates, organothiophosphates, pyrethroids, simmtriazines, esters, strobilurins, thiocarbamates, triazoles, etc.) in winter wheat grain by gas chromatography with mass spectrometric detection has been developed and validated by experimental data. The developed extraction method of sample preparation is simple, quick, consumes only cheap and rather common reagents and provides extracts clean enough to obtain reproducible quantitative results without cleaning of injector liner at least for 200 injections. The recovery values of studied pesticides from winter wheat grain were between 76 and 118 % with RSD values below 9 % at 10.0, 20.0 and 200 µg·kg^–1 spiking levels. Detection limits were less or equal to 0.01 mg·kg⁻¹ for all the studied pesticides. The obtained limits of quantification were below or equal to the maximum residue levels (MRLs) which are set by Belarus and the European Union for the corresponding pesticides in cereal grains. The linear range used in the calibration curves was from 50 to 3000 µg·L^–1 with the values of the determination coefficients R² more than 0.997. The developed method was successfully used for the analysis of cereal grains for the residues of the pesticides, which were under registration trials held in Belarus in 2015. 

Ritter’s reaction of pulegone with a number of both aliphatic and aromatic nitriles in the presence of catalytic amount of concentrated sulfuric acid proceeding through formation of a tertiary carbocation with the subsequent addition of nitrile molecule and formation of ketoamides, has been performed.

Human glutathione S-transferase P1-1 (GSTP1-1) is an important enzyme in clinical diagnostics since its overexpression in solid tumours and lymphomas largely contributes to multiple drug resistance of cancer cells. Small amounts of the enzyme can also be isolated from erythrocytes. However, known isolation methods are disadvantageous and do not allow to obtain the purified enzyme in good yield and with high specific activity (≥ 100 U/mg protein). In order to elaborate more effective purification procedure for the erythrocyte GSTP1-1, we have for the first time synthesized and investigated glutathione-containing affinity membranes based on chemically modified cellulose paper. The membranes have been shown to successfully replace conventional glutathione-agarose affinity gels in the enzyme purification. To isolate and purify GSTP1-1 from erythrocyte hemolysate, a novel two-step method has been developed involving preliminary hemoglobin removal on a small anion exchange column and further affinity chromatography on the cartridge with glutathione-containing membranes. In terms of activity yield (76.5%), purification factor (23589-fold), and specific activity of the purified enzyme (104.5 U/mg), the method is notably superior to previously published procedures. Gel electrophoretic and MALDI-TOF mass spectrometric analyses reveal apparent homogeneity (≥ 95%) of the obtained preparation. Steady-state kinetic parameters have been determined for the purified GSTP1-1 in the conjugation reaction between glutathione and 1-chloro-2,4-dinitrobenzene at pH 6.5 and 25 °С: for the former substrate, K_m = 0.19 mМ, k_cat = 47.8 s^–1; for the latter, K_m = 0.68 mМ, k_cat = 54.3 s^–1. The results of the present work may be useful for screening new enzyme inhibitors with possible antitumour activity. The affinity membranes may also find application in isolating native and recombinant glutathione S-transferase (GST) isoforms from various sources, as well as fusion proteins with GST tag. 

The results of comprehensive research on improving the quality of majolica ware by harmonizing in the system «ceramic base – glazed coating» are presented in the article. A modern approach to solving problems, including hierarchical modeling, part of which is to create a cluster of structures, combining the technological steps of preparing a ceramic product of the desired quality in a single entity – the technological process was used in the work. Experimental studies, confirming the correctness of this approach, have improved physicochemical properties of majolica and ensure the operational reliability during thermal processing of dishes in dishwashers of various types. It has been shown that the production of high-quality majolica ware is based on the harmonization of the ceramic base and the decorative coating, so the development of a ceramic mass and glaze coating with a specific set of technological and physicochemical properties should be given absolutely equal attention. The above approach provides efficient and logically sound improvement of the production technology for high-quality majolica products.

The effect of the parameters for extraction process of chamomile and peppermint with 1,2-propylene glycol upon the efficiency of extracting has been studied. Dependencies upon the temperature, the process duration and the extractant – extractive ratio upon the content of extractives in the extracts have been studied. It has been established that with decreasing the ratio of raw materials to solvent, and increasing the temperature and the duration of the process, the content of extractives increases reaching the maximum at 240 mg/g for peppermint and 160 mg/g for chamomile. This content of extractive substances is provided under the following conditions: for chamomile – ratio of raw materials: 1,2-monopropylene glycol – 1: 10, temperature – 56 °C, extraction time – 50 min; For peppermint: 1: 10, 60 °C, 50 min respectively.

Antibodies are an essential tool being a part of immunodiagnostics, therapeutics and life science research instruments. In this paper we analyze the recent developments in recombinant antibodies generation by means of phage display technology. We also provide our own results dedicated to antibodies development process. Analysis of antibody-antigen complexes with resolved structures allow to create synthetic phage display library of Fab antibody fragments with the diversity of 1010 independent clones. Utilizing a negative selection approach, we succeeded in generation and characterization of specific single-domain antibodies that has substantially different binding kinetics to CYP11B2 and CYP11B1 isoenzymes – proteins with 93% sequence identity. We also generated specific binders to a few high-molecular weight human antigens – erytropoetin, growth hormone and thyroperoxidase.

The review article summarizes data on synthesis of new derivatives of maleopimaric acid (the most available diterpenoid acid, isolated from maleated rosin) – esters, amides, imides, imido amides, imido esters, diimido acids etc. and of oxygen- and nitrogen containing derivatives of previously unknown citraconopimaric acid. The article mainly covers the literature data since 2000 year as well as work carried out in the Institute of Chemistry of New Materials of NAS of Belarus.