An original phenobarbital anticonvulsant Halonal, 5-ethyl1-(2-fluorobenzoyl)-5-phenylpyrimidine-2,4,6(1H,3H,5H)- trione, stimulated the cellular immune and the humoral response in long-term alcoholized male (CBAxC57Bl/6) F1 mice to the level of healthy animals. Voltammetry was found to be suitable for determination of Halonal R / S-enantiomeric ratio, which was exemplified on the authentic sample with the R / S-composition of 40 : 60. Molecular docking (Schr & ouml;dinger program, Glide) showed that Halonal behaved as a benzonal derivative interacting with GABAAR via the BARB binding site, with S-Halonal having higher similarity score than its R-enantiomer because of a different orientation of the 2-fluorobenzoyl substituent.

The high catalytic activity of arenediazonium, along with the ability of gold ions to form specific bonds with amikacin, has been used in the fabrication of an electrochemical sensor based on a glassy carbon electrode modified with a gold solution and arenediazonium tosylate (Ar/GGCE) for the detection and quantification of amikacin upon its release from implants. Atomic force microscopy, cyclic voltammetry, and square-wave voltammetry were used to demonstrate that the use of a gold solution and arenediazonium tosylate for the surface modification of a glassy carbon electrode significantly enhances the electrode characteristics. The determination of amikacin was achieved using square wave voltammetry, which enabled the detection of amikacin at the Ar/GGCE in the concentration range 0.2–60 μM and ensured a limit of detection of 0.058 μM for amikacin released from implants.

In this work two strategies for the synthesis of peroxidase silver conjugates for the qualitative and quantitative determination of immunoglobulins (IgG) to ixodid tick-borne borreliosis (ITBB) (Lyme disease) in human serum were proposed. The first approach for Ab-HRP@AgNP conjugate synthesis involved silver nanoparticles (Ag NPs) capped with a commercial peroxidase conjugate (Ab-HRP) by passive adsorption. The second strategy was based on the initial coupling of Ag NPs with human anti-species antibodies (Ab) by passive adsorption followed by the introduction of horseradish peroxidase (HRP) enzyme into the reaction mixture as a blocking reagent for Ab@AgNP@HRP conjugate synthesis. The formation of peroxidase silver conjugates was proved by UV/Vis spectroscopy and Transmission Electron Microscopy (TEM). The catalytic activity of Ab-HRP@AgNP and Ab@AgNP@HRP conjugates was evaluated by Michaelis-Menten kinetics. A commercially available 96-well microtiter plate with recombinant antigens to ITBB was used as a platform for immobilization of analyzed IgG. The HRP in Ab-HRP@AgNP conjugate was found to retain a sufficient level of activity for interaction with the H2O2 substrate to form an intensely colored reaction product. Therefore Ab-HRP@AgNP conjugate can be used in enzyme-linked immunosorbent assay (ELISA) with spectrophotometric detection of 3,3',5,5'-Tetramethylbenzidine (TMB Ox) for quantitative determination of IgG to ITBB in human serum in the concentration range 12.5-800 ng ml(-1) with LOD 2 ng ml(-1). Ab@AgNP@HRP conjugate is recommended for the electrochemical determination of IgG to ITBB in human serum at LOD 3 ng ml(-1) with registration of silver oxidation by linear sweep anodic stripping voltammetry (LSASV). Ag NPs in Ab-HRP@AgNP and Ab@AgNP@HRP conjugates do not change electrochemical activity during storage and can be used as an electrochemical label in LSASV method in case of HRP inactivation. The immunoassay based on peroxidase silver conjugates expands the analytical potential for the determination of IgG to ITBB especially during the period of increasing incidence.

A highly sensitive electrochemical sensor based on arenediazonium tosylates was designed to detect meldonium in urine. The effect of the concentration of ArN2(+)OTs(-) arenediazonium tosylate modifier and various substituents was studied. Basic operating parameters for voltammetric meldonium detection were established and the procedure for urine sample preparation was developed. The following values were obtained: limit of detection (LOD) 0.005 mg .L-1 (P=0.95) and limit of quantification (LOQ) 0.01 mg .L-1. The relationship between the analytical signal and meldonium concentration in the solution ranging from 0.01 to 400 mg .L-1 was described by a linear function. The meldonium concentration error did not exceed 18 %. The analysis time for a single urine sample was reduced to 15 minutes.

A promising method for improving the functional properties of calcium-phosphate coatings is the incorporation of various antibacterial additives into their structure. The microbial contamination of a superficial wound is inevitable, even if the rules of asepsis and antisepsis are optimally applied. One of the main problems is that bacteria often become resistant to antibiotics over time. However, this does not apply to certain elements, chemical compounds and drugs with antimicrobial properties. In this study, the fabrication and properties of zinc-containing calcium-phosphate coatings that were formed via micro-arc oxidation from three different electrolyte solutions are investigated. The first electrolyte is based on calcium oxide, the second on hydroxyapatite and the third on calcium acetate. By adding zinc oxide to the three electrolyte solutions, antibacterial properties of the coatings are achieved. Although the same amount of zinc oxide has been added to each electrolyte solution, the zinc concentration in the coatings obtained vary greatly. Furthermore, this study investigates the morphology, structure and chemical composition of the coatings. The antibacterial properties of the zinc-containing coatings were tested toward three strains of bacteria-Staphylococcus aureus, methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa. Coatings of calcium acetate and zinc oxide contained the highest amount of zinc and displayed the highest zinc release. Moreover, coatings containing hydroxyapatite and zinc oxide show the highest antibacterial activity toward Pseudomonas aeruginosa, and coatings containing calcium acetate and zinc oxide show the highest antibacterial activities toward Staphylococcus aureus and methicillin-resistant Staphylococcus aureus.

A highly sensitive electrochemical sensor based on a Surface Active Modifier (SAM) consisting of Taunit-M carbon nanotubes and mesoporous carbon (NanoTechCenter LLC, Tambov, Russia) is developed for the voltammetric determination of betulin and p -nitrophenol. The effect of the modifier concentration on the electrode surface on the analytical signal of betulin was studied, and a method for modifying the surface of the SAM graphite electrode was developed. The developed method is easy to use, fast, stable, sensitive, and cost-effective procedure, which can be used to detect these analytes in real samples. Voltammograms of p -nitrophenol were obtained for the first time on the developed modified electrochemical sensor and the dependence of the height of its analytical signal on the pH of a phosphate buffer thus obtained was studied in a wide pH range from 4 to 12, a background electrolyte with optimal pH was also chosen. Proceeding from the calibration dependences of the height of the betulin analytical signal on the concentration obtained for various background electrolytes with different pH and cation-anion composition, a background electrolyte with the maximum sensitivity of the analytical signal was selected on a modified electrochemical sensor. Study of cyclic voltammograms was carried out to understand the electrode processes, exhibiting a pronounced peak of anodic oxidation observed in a potential range from 0.7 to 0.9 V. However, there was no peak in the cathodic direction which indicates the irreversible nature of the electrode process. When determining the nature of currents, the Semerano criterion equal to 1.6 was calculated, which indicates the absence of the contribution of the diffusion component of the current. Verification of the correctness of the voltammetric method for determining betulin on a new electrochemical sensor was carried out using the «spike-test» method. The data obtained show that the voltammetric determination of betulin can be carried out with a measurement error not exceeding 15%. The proposed modified electrodes were compared with previously known electrodes for the determination of pentacyclic triterpenoids and pesticides at concentrations of 0.5 × 10 –3 – 8.0 × 10 –3 mg/dm 3 .

Biocompatible poly(lactide-co-glycolide) scaffolds fabricated via electrospinning are having promising properties as implants for the regeneration of fast-growing tissues, which are able to degrade in the body. The hereby-presented research work investigates the surface modification of these scaffolds in order to improve antibacterial properties of this type of scaffolds, as it can increase their application possibilities in medicine. Therefore, the scaffolds were surface-modified by means of pulsed direct current magnetron co-sputtering of copper and titanium targets in an inert atmosphere of argon. In order to obtain different amounts of copper and titanium in the resulting coatings, three different surface-modified scaffold samples were produced by changing the magnetron sputtering process parameters. The success of the antibacterial properties' improvement was tested with the methicillin-resistant bacterium Staphylococcus aureus. In addition, the resulting cell toxicity of the surface modification by copper and titanium was examined using mouse embryonic and human gingival fibroblasts. As a result, the scaffold samples surface-modified with the highest copper to titanium ratio show the best antibacterial properties and no toxicity against mouse fibroblasts, but have a toxic effect to human gingival fibroblasts. The scaffold samples with the lowest copper to titanium ratio display no antibacterial effect and toxicity. The optimal poly(lactide-co-glycolide) scaffold sample is surface-modified with a medium ratio of copper and titanium that has antibacterial properties and is non-toxic to both cell cultures.

A high chemical resistance inherent in the alloys based on platinum group metals is one of the reasons for a number of difficulties that arise when dissolving such materials. Nowadays, the dissolution in aqua regia is one of the most effective methods for dissolving corrosion-resistant alloys. The main disadvantage of this method is a release of toxic gaseous substances such as nitrosyl chloride and nitrogen oxides. To decrease the volume of gases thus released without reducing the redox potential of the system, we proposed a method of dissolving a Pt – Rh alloy in HCl-HNO3 with a controlled dosed supply of HNO3 at a given value of the oxidation-reduction potential (ORP) of the system. The potential of the system has been chosen proceeding from the potential for HNO3 – HCl – Pt and HNO3 – HCl-Rh systems and amounted to 0.85 and 0.9 V. The impact of the dispersion and the inherent flaw of PtRh alloys on the dissolution indices of the alloy was also considered. It is shown that the dissolution of a Pt – Rh alloy with a rhodium content of 15 % in HCl – HNO3 at a constant value of ORP = 0.9 V compared to the use of the classic mixture (HCl:HNO3 = 1:3 vol.) provides a decrease in nitric acid consumption by 40%, reduction of the process time, increase in the recovery factor for both platinum and rhodium, and a two-fold reduction of the volume of released nitrogen oxides (theoretical calculation). It is also revealed that the process of mechanical activation of the alloy reduces the dissolution time and leads to almost quantitative dissolution of the sample.

Current article presents the results of using a solid carbon-containing electrochemical sensor modified with arenediazonium salts (ME-ADT-COOH) for the joint determination of copper and mercury in human hair. The sensitivity of the determination of copper and mercury ions using a graphite electrode modified with gold and arenediazonium salts with a substituent carboxy group is higher compared to the other carbon-containing modified electrodes. The influence of the concentration of arenediazonium tosylates with various substituents on the obtained analytical signal was studied. The conditions for the manufacturing the new carbon-containing modified electrochemical sensor have been developed. The effective surface area of the modified electrode was calculated, which was estimated using a cyclic voltammogram against the background of 0.1 M KCl with the addition of potassium hexacyanoferrate (С=5*10-4mol/l) salts and calculated using the Randles-Ševčík equation for the reversible electrode process. A linear range of determined concentrations in the voltametric determination of microelements on the arendiazonium-modified gold-graphite electrode was established - from 0.1 to 12 µg/g. The error of the determination did not exceed 25 %. The correctness of the results of the determination of copper and mercury in real objects by the “introduced-found” method, which correlates well with the known values, has been verified.

This article presents the results on using a new electrochemical sensor modified with arenediazonium salts (MGE-Cu-COOH) to determine selenium in biological fluids (blood serum). It was shown that the sensitivity of the determination of selenite ions using this modified electrode is higher compared to that of the unmodified one (MGE-Cu). The effect of the concentration of arenediazonium tosylates on various substituents was studied, and the conditions for the production of the electrochemical sensor were developed. The surface of the modified electrode was investigated using SEM. The increase in the effective surface area of the electrode was found to be due to the formation of a system of ultramicroelectrodes. In biological samples, the LOD and LOQ of selenium were established at the levels of 0.057 and 0.166 μg l-1, respectively. Finally, the correctness of the results on selenium determination in real samples by the "input-found" method, which correlates well with the known value, was verified.

Selenium (Se) is an essential atom in living organisms but some aspects of its metabolism and function remain unknown. Se large deficiencies cause significant disturbances of cardiovascular system and left ventricle (LV) fibrosis. The studies are needed to characterize the significance of Se in post-infarct LV dysfunction and postoperative remodeling. In Tomsk region, the level of Se in hair of healthy people and in myocardium of patients with ischemic cardiomyopathy was not changed. Chemical analysis of hair samples and myocardium of LV for Se content was based on a stripping voltammetry for determining the mass concentrations of this microelement. Nevertheless, a significant number of cardiac surgical patients showed a negative dynamics of postoperative LV myocardial remodeling with progression of heart failure. We obtained preliminary results on the direct relationship between favorable outcomes of postoperative adaptive myocardial remodeling (AR) and maladaptive myocardial remodeling (MALR) with variations in Se concentrations in the myocardium. At the same time, there were 84 % of cases with abnormal postoperative MALR of LV in the presence of extremely high (toxic) Se content in the myocardium. Further in-depth studies are required to translate novel data from the laboratory bench to the clinics.

Selenium (Se) is an essential micronutrient in living organisms; however, some aspects of its metabolism and function remain unknown. Se deficiency causes significant disturbances in the cardiovascular system along with left ventricular (LV) fibrosis. Simultaneously, an understanding of pathways that influence Se role in heart failure progression is insufficient. Therefore, clinical studies are needed to characterize Se importance in developing post-infarct LV dysfunction and postoperative remodeling. In the Tomsk region, the level of Se in healthy people and the myocardium of patients with ischemic cardiomyopathy was close to normal. Quantitative chemical analysis of Se content in hair samples and LV myocardium was based on stripping voltammetry to determine mass concentrations of the micro-element. Nevertheless, a significant number of cardiac surgery patients showed negative dynamics of postoperative LV myocardium remodeling with the development of heart failure. We obtained preliminary results of a direct correlation between favorable outcomes of postoperative adaptive myocardial remodeling (AR) and maladaptive myocardial remodeling (MALR) with different Se concentrations in the myocardium. Simultaneously, about 84% of patients showed abnormal postoperative LV MALR in high Se in the myocardium. Further in-depth studies are required to translate novel data from the laboratory bench to the clinics.

30% of industrial workers have a chronic (at least 3-4 months) zinc deficiency as a vital trace element necessary for the functioning of a significant amount of metalloproteins. The cause of zinc deficiency may be copper intoxication noted earlier, which together is important for the development of structural pathology of internal organs.

The kinetics of salicin acid hydrolysis in aqueous solutions were studied. The salicin content in the reaction mixtures was determined by HPLC with UV detection. The salicin hydrolysis rate depended more on the solution acidity than on the temperature. The dependences of the salicin hydrolysis rate constant on temperature and solution acidity were established. Salicin was most reactive in aqueous solutions at 90°C and pH < 1.0. Salicin preparations could be stored for more than one year without noticeable decomposition at room temperature and pH > 2.0

The method of carbon containing electrode ( CCE ) modification with tosylated arendiazonium salts ( ADT ) was proposed for the voltammetric ( VA ) determination of caffeine in beverages. The comparison of chemical spontaneous and electrochemical modification approaches was carried out for ADT modified CCE for VA caffeine determination for the first time. A new class of ADT is characterized by high solubility and stability for one month that plays significant role in the process of electrode surface modification. Salts with nitro and carboxy substituents were tested. The optimal conditions for the spontaneous chemical modification of the CCE were selected: ADT modifier with NO 2 substituent, electrode immersion time in the modifier solution for 10 seconds, modifier concentration of 5 mg / dm 3 . ADT deposition on the electrode surface was confirmed by the IR spectroscopy and scanning electron microscopy with the formation of covalent bonds between the carbon atoms of electrode surface and the benzene rings of the modifier. It was shown that the electroactive surface area increases by two times after the modification. Consequently, the technique sensitivity increasing the detection limit of 51 mg / dm 3 and linear range extension from 154 up to 500 mg / dm 3 was observed. While applying the modified electrode, the analysis time was reduced to 15 minutes. Furthermore, the suitability of CCE modified with NO 2 substituent was tested for the analytical purposes. As a result, the caffeine was determined in some tonic and carbonated drinks. The comparison of the results obtained by the proposed method with ADT modified CCE and the level declared by the manufacturer was carried out. The high compliance was established. In addition, the obtained data was consistent with the results by the independent spectrophotometric method.

In this study, mechanical-electrical transformations were excited in heterogeneous solid materials. Electromagnetic signals were excited in rock samples via determined acoustic pulses. The main patterns of changes in the electromagnetic signals' amplitude–frequency parameters at the contacts of the rock samples with distilled and mineralised water were determined. We find that contact with distilled water decreases the electromagnetic signal and spectral component amplitudes, while contact with brine leads expands the spectrum. The laws determining the changes in the parameters of the electromagnetic signals and their spectra in porous sandstone samples saturated with water or salt solutions are given. Based on our results, a method is proposed to quantify the salinity of natural water contained in oil or other sources based on changes in the electromagnetic signal parameters when such water comes into contact with rocks.

The issues of good health and well-being for people have been reflected in the UN Sustainable Development Goal No. 3. The presented paper focuses on the increase in the copper content in the body by 3-4 times within 3-4 months. It is established that such an increase is not accompanied by a change in the biochemical parameters of blood and the structure of somatic pathology characteristic of the population of Tomsk, who are not engaged in industrial production.

Aim: to review current scientific literature concerning the main advances and problems of magnesium (Mg) alloys for traumatology and orthopedics. Methodology of the study. Analytical review based the comprehensive investigation of public scientific and technological sources. Results of the study. Modern knowledge about classification, in vitro and in vivo biodegradation, biomechanics, local and general biocompatibilities, clinical efficacy, and hazards of infectious complications in conditions of osteosynthesis with implants made of Mg alloys with or without protective (anticorrosion and antimicrobial) coatings is presented. Conclusion. Fast degradation and a risk of periprosthetic infection strongly limit clinical application of implants made of Mg and its alloys. Development of novel Mg alloys and their modification by incorporating antimicrobial elements into their body or protective coating is a promising direction to control biomedical characteristics of Mg alloys.

The electrochemical behavior of a number of benzoyl barbiturates was studied using a glassy carbon electrode (GCE). The kinetics of the electrode process is determined, the contribution of physical adsorption to the electrochemical process is estimated, and the mechanism of the possible electrochemical reaction is proposed. It is shown that the electrochemical reduction potentials of benzoyl phenobarbital derivatives are determined by the LUMO energies, calculated by the B3LYP 6-311+G method. It is established that the process is quasi-reversible, complicated by adverse reactions. The influence of halogen type and its position in the benzoyl residue of the studied substances on the analytical signal is established. The effective values of the dissociation constants of various forms of benzoyl derivatives were calculated using the example of halonal, for which the values 3.16 center dot 10(-8) and 6.31 center dot 10(-12), respectively, were found.