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The main factors governing the dimer–monomer self-assembly in 6H-1,4-diazepinoporphyrazines are shown.

The work on the development of a generator of high-power, high-frequency pulses based on a nonlinear transmission line with saturated ferrite is presented. A feature of the generator is that the ferrite rings are saturated in the field of permanent magnets, unlike traditional generators with a solenoid wrapped around the transmission line. Due to the changed structure of the inner conductor, which is a corrugated conductor, the line has spatial dispersion. The paper demonstrates the generation of high-frequency pulses with a duration of up to 6 ns and a center frequency of 2.7 GHz. This pulse duration with a frequency above 2 GHz was not previously observed in traditional nonlinear transmission line geometry. The maximal peak power achieved was 70 MW for an incident voltage pulse of 90 kV. The energy efficiency of video pulse energy conversion into radio pulse was 6% [G. Kataev, Electromagnetic Shock Waves (Sov. Radio, Moscow, 1963)]. The paper discusses the performance of RF and microwave NiZn ferrites for the purposes of radio pulse generation.

The paper highlights modern views on the metabolism of vitamin D in the human body. The analysis of the literature data on the mechanisms of the effect of vitamin D deficiency on the pathological processes occurring in the skin with psoriasis is carried out. It is known that psoriasis is associated with a high prevalence of metabolic syndrome, diabetes mellitus, and cardiovascular diseases. There is a direct correlation between a decrease in vitamin D levels and an increased risk of developing metabolic syndrome and cardiovascular mortality, including in patients with psoriasis. Data on the possibility of using vitamin D in dermatology are presented. Based on international and Russian clinical recommendations, the place of oral colecalciferol preparations in the prevention and correction of vitamin D deficiency and deficiency has been determined. The use of oral vitamin D for the simultaneous treatment of psoriasis and metabolic syndrome reduces the risk of cardiovascular diseases and type 2 diabetes mellitus. We analysed the international and domestic recommendations for the treatment of vitamin D deficiency and insufficiency, the use of which makes the oral administration of vitamin D3 (cholecalciferol) optimal for the treatment and prevention of vitamin D deficiency, as the results of several studies showed a higher efficacy of vitamin D3 vs vitamin D2. Vitamin D3 is found in vitamin D-fortified foods and is available as dietary supplements and drugs. The bioavailability of vitamin D in dietary supplements may differ depending on the used vehicle substance.

The research aims at studying the dynamics and character o f disorders in the target-organs and appraisingthe quality оf life in women with surgical menopause (SM ) on the background o f hormonal replacement therapy (HRT).Application o f Femoston as the preferable preparation was determined by functional state оf estrogen-dependent organs (cardiovascular system, bone tissue, and mamma) and accompanying extragenital diseases.Hormonal replacement therapy effectively reduces early climacterics disorders connected with menopause and promotes prophylaxis o f late complications o f menopause development (cardiovascular disease and osteoporosis). Femoston is the preparation o f choice fo r women with surgical menopause as it exerts minimum influence on the metabolism and doesnt have anabolic or glucocorticoid effects.

Theoretical studies of the shape of the linear potential sweep voltammogram for a reversible electron-transfer reaction have been overviewed. Two different expressions for the current–potential dependences have been proposed therein. Our analysis has shown that this divergency originates from the implicit difference of the assumptions on the pretreatment procedure before the beginning of the potential sweep. Two principal variants of such pretreatment have been considered in detail: (1) potentiostatic exposure to the potential equal to the starting one for the subsequent sweep, E = Ei; (2) OCP (zero current) regime. In the former variant, the potentiostatic regime during the pretreatment period shifts the surface concentrations from their bulk values to the steady-state ones (dependent on Ei). It induces current passage of a diminishing amplitude due to the diffusion-layer expansion. If the pretreatment period is sufficiently long (well over 10 s in water) a time-independent distribution of the reactant and product concentrations is established across the steady-state diffusion layer accompanied by the current stabilization, i ≅ iss. At the starting moment of the potential sweep, t = ti, both the potential and the surface concentrations are continuous as functions of time so that the amperometric response for t > ti increases in time from its steady-state value, i ≅ iss, due to the potential sweep, with its gradual approach to a universal dependence which corresponds to the response of the system if the potential sweep starts very far from the half-wave potential where the equilibrium concentration of the reaction product is extremely low. In the latter variant of pretreatment there is a stepwise change of the potential and of the surface concentrations at t = ti; it leads to a Cottrell-type contribution to voltammetric current which in the course of the potential sweep is supplemented by another contribution corresponding to the above universal response where the sweep starts very far from the half-wave potential. As a result, after a relatively short relaxation period the current responses in both variants approach its universal behavior. Method of a direct determination of the number of transferred electrons per consumed reactant species has been proposed. Approximate analytical expression for the dependence of current on time after passage of the current's peak has been derived. Predicted features have been verified with the use of a well-known reversible reaction: ferrocene oxidation in acetonitrile.

The present report describes a 20-year old man who developed an incessant atrial tachycardia several days after snakebite. Antiarrhythmic treatment was ineffective and six months later radiofrequency ablation of atrial tachycardia was successfully performed. A chronic arrythmia was considered as manifestation of toxic-allergic myocarditis. The possible mechanisms leading to myocarditis are discussed.

Background: Adequate diagnosis of recurrent atrial fibrillation after the surgical treatment in patients with paroxysmal forms of the disease appears to be a difficult task. Aims: The manuscript is devoted to a comparative analysis of the results of subjective and objective assessment of atrial fibrillation recurrence after cryoballoon ablation of the pulmonary veins. Material and methods: 301 patients were included in the study. All of them consequentially underwent cryoballoon ablation of the pulmonary veins in the period of October, 2016 November, 2019. The inclusion criteria were as follows: symptomatic atrial fibrillation; confirmation of atrial fibrillation by instrumental diagnostic methods. The exclusion criteria were the following: a combination of atrial fibrillation and atrial flutter at the time of surgery; history of open-heart procedures and catheter procedures to cease atrial fibrillation; the presence of concomitant cardiac and "arrhythmogenic" pathology. Results: In the period of May 01-30, 2020, 100% (n=301) of the patients included in the study were assessed by the method of targeted survey. The median duration of the postoperative period to the time of a patient's survey was 21 (3; 43) months. The interviews have shown that 136 (45%) patients noted a return of complaints associated with atrial fibrillation recurrence in the postoperative period. There was a clear tendency towards a decrease in the total number of patients with complaints of the clinical recurrence of the disease, depending on the time elapsed since the surgical procedure. The longer the period from the moment of surgery, the lower the number of patients with recurrence. Of 136 patients with recurrent complaints associated with atrial fibrillation, 97 (71%) were able to conduct the daily electrocardiogram monitoring. Of these, the instrumental recurrence of atrial fibrillation was confirmed in 59 patients, which amounted to 20% of all the patients included in the study (n=301). Conclusion: To establish the true number of atrial fibrillation recurrence after cryoballoon ablation of the pulmonary veins, a targeted survey of patients is desirable for up to 12 months after the surgery. The patients with complaints which suggest atrial fibrillation recurrence, even if these complaints do not correspond to the preoperative ones, should be invited for the instrumental diagnostics of arrhythmia.

In recent years, the key principles of the electric power industry have radically changed and the number of studies on the development of devices for electrical energy storage in a different form such as mechanical or chemical energy has rapidly increased. This review gives a brief description of these devices. The attention is focused on redox flow batteries (RFBs), a promising type of energy storage devices capable of efficiently operating in distributed power grids, in order to eliminate the imbalance between the time-varying electricity production by ‘unconventional sources’ and electricity consumption. At the design level, RFBs combine the principles of fuel cells and chemical energy sources with solid electroactive materials: transitions between electrical and chemical forms of energy in these devices occur upon oxidation and reduction of redox-active electrolytes, which are stored in separate tanks and pumped into the electrode compartments of the membrane electrode assembly (MEA) separated by a semi-permeable membrane. This approach ensures an important advantage of these devices over other types of chemical energy sources, that is, the possibility of independent scaling of the energy storage capacity and power characteristics of the system. This review provides a systematic description of the main types of RFBs and analysis of their fundamental benefits and drawbacks, which determine the prospects for practical applications of RFBs. The bibliography includes 149 references.

Background: Pre-excitation syndrome (premature excitation of the ventricles) is a congenital anomaly in the structure of the cardiac conduction system and consists in the presence of an additional atrioventricular connection. The possibility to assume the presence of pre-excitation syndrome accompanied by tachycardia based on an electrocardiogram provides a clue to the correct diagnosis and subsequent treatment of the patient. Clinical case description: A clinical case of a 56-year-old patient is presented, who was admitted to the FRCC of the FMBA of Russia in January, 2021 with paroxysms of previously undiagnosed tachycardia. During Holter monitoring, an episode of heart palpitations was recorded. When analyzing an ECG fragment, it was possible, by calculating the tachycardia cycle length, to suspect the presence of a latent ventricular pre-excitation syndrome, which was accompanied by the development of orthodromic atrioventricular reciprocal tachycardia with a bundle branch block on the side of the additional atrioventricular connection (ipsilateral block). The patient underwent endocardial electrophysiological examination to confirm the presence of the bundle, followed by the catheter treatment of the atrioventricular connection. A good postoperative clinical result was obtained. Conclusion: It is important to be able to make a differential diagnosis between the presence of a latent pre-excitation syndrome with the development of orthodromic atrioventricular reciprocal tachycardia with the bundle branch block on the side of the extra atrioventricular junction (ipsilateral block) and other supraventricular tachycardias with an aberration along one of the bundle branches, in order to determine the tactics of the patient management and to control the effectiveness of the treatment.

The need for an integrated approach to the preservation and health promotion of school children, firstly due to low level of student health and its worsening dynamics; secondly, a variety of factors, including uncounted factors, that have an impact on health status and dynamics; thirdly, the narrowness and fragmentation of health preservation practice. An integrated approach has two dimensions – horizontal and vertical. The horizontal dimension provides highlighting significant aspects of health preservation, the vertical dimension – its levels. Nine aspects of an integrated approach to the health preservation of schoolchildren are highlighted and described: conceptual, political, legislative, technological, medical and educational, social, “co – participating, educational, organizational and technological. Particular attention is paid to agreement that priority lies in the health of students, along with their education and upbringing, their political and legal consolidation, organizational and technological implementation. Also, five levels of health preservation management processes are highlighted: personal, school, municipal, regional, federal.

Methodology based on a combination of experimental data obtained by in situ methods of spectroelectrochemistry and electrochemical quartz crystal microbalance has been proposed for determination of the key parameters of the conjugated polymer deposition on the electrode surface via monomer electrooxidation. These parameters are: the current efficiency of the process, the charge spent per an oxidized monomer molecule, the number of monomer units inside the deposited film, and the average number of valence bonds per one monomer unit inside the film. Besides, the electrochemical quartz crystal microbalance method applied to the discharge process of the electropolymerized film allows determining the average charging (oxidation) degree of the monomer unit at the polymerization potential and the degree of the solvent participation in the polymer’s redox transitions. The applicability of the proposed approach has been demonstrated by example of magnesium polyporphine films obtained by oxidation of unsubstituted magnesium porphine on inert electrode in acetonitrile solution at a low potential.

The quality of ion-selective membranes determines the efficiency of Vanadium Flow Batteries (VFBs), and alternatives to expensive Nafion™ materials are actively being searched for. One of the membrane architecture approaches is to imitate the Nafion™ structure with two separate phases: a conductive sulfonated polymer and an inner matrix. We introduce a new composite material based on sulfonated styrene polymerized inside the pores of a stretched PTFE matrix. Variation of polystyrene content and a sulfonation degree allowed to obtain membranes with IEC from to 0.96 to 1.84 mmol/g. Balanced vanadium permeability (ca. 5.5 ⋅ 10-6 cm2 /min) and proton conductivity (ca. 50 mS/cm) were achieved for the material with 21-23 % polystyrene content and a sulfonation degree up to 94 %. Membranes showed stable cycling with 81 % energy efficiency in a single-cell VFB. This work contributes to the existing knowledge of Nafion alternatives by providing a cheap and scalable method of membrane production.

Changes in the indicator electrode potential (at zero current) E and (quasi) equilibrium composition of aqueous solution in the anode chamber of the model electrolyzer, which initially contained 0.5 M concentration of bromide anions, provided that the solution was kept at a constant pH and constant (together with the gas phase above it) total number of Br atoms in all its compounds, are calculated. Theoretical analysis was carried out for four different hypotheses regarding the possible extent of electrolysis and the nature of the processes are theoretically analyzed. They are: (1) no formation of bromine compounds with positive oxidation states occurs, i.e., electrolysis only leads to the formation of molecular bromine in its various forms (the dissolved state of Br2, as well as phases of liquid bromine $${\text{Br}}_{{\text{2}}}^{{{\text{liq}}}}$$ , and bromine vapor in the gas space above the $${\text{Br}}_{{\text{2}}}^{{{\text{vap}}}}$$ solution); (2) oxidation of bromide ions leads to the formation of bromine compounds in its oxidation state up to +1 inclusive; (3) the process proceeds with the formation of both bromate ion (BrO3-) and compounds of bromine with lower oxidation states in solution ( $${\text{Br}}_{{\text{3}}}^{ - },$$ $${\text{Br}}_{{\text{5}}}^{ - },$$ Br2, $${\text{Br}}_{{\text{2}}}^{{{\text{liq}}}},$$ $${\text{Br}}_{{\text{2}}}^{{{\text{vap}}}},$$ BrO–, HBrO); (4) in addition to the components specified in clause (3), the formation of the perbromate anion $$\left( {{\text{BrO}}_{{\text{4}}}^{ - }} \right)$$ is also taken into consideration. All electrochemical and chemical reactions involving bromine-containing species have been taken into consideration in the hypothesis framework of the system’s evolution (1), (2), (3), or (4), are assumed to be in a (quasi)equilibrium state. Predictions for all hypotheses (1), (2), (3), or (4) have been compared at three different pH values of the solution (2, 6 and 10 of Br-containing anolyte composition’s evolution in the course of electrolysis.

Material and charge balances in the course of the electropolymerization process of the non-substituted Mg(II) porphine (MgP) at a low oxidation potential from its acetonitrile solutions of various concentrations have been studied via the in situ electrochemical quartz crystal microbalance method (EQCM). Thus, registered electrode mass increase due to the MgP oxidation at its surface has been used, in combination with in situ spectroelectrochemical data, for determination of the key parameters of the polymerization process and of the magnesium polyporphine films deposited on the electrode surface: current efficiency of the film deposition process, average charge spent for transformation of a monomer molecule into monomer unit inside the film, number of monomer units inside the deposited film, average number of valence bonds per one monomer unit inside the film. Besides, the EQCM method applied to the discharge process of the electropolymerized film has allowed us to estimate the average charging (oxidation) degree of the monomer unit inside the film at the polymerization potential and the degree of the solvent participation in the course of the polymer’s redox transitions. It has been established that the number of bonds between porphine units is within the range of 2.2 to 2.4, with its slight increase for films deposited at higher monomer concentrations. Conclusions on the structure of polyporphine chains have been made.

The vanadium redox flow battery (VRFB) is the most promising type of rechargeable power sources for medium- and large-scale energy storage devices for modern power systems. The intensive research and development activity of leading world centers aimed at optimizing the key element of the VRFB—the membrane electrode assembly (MEA)—necessarily includes testing new electrode materials, catalytic layers, electrolytes, and membranes, as well as their combination in the test cell. Here, an original design of an MEA test cell is proposed that significantly simplifies the assemblage procedure and makes it possible to increase the flow field variability by replacing massive graphite or graphite/polymer plates with sheets of extruded thermally expanded graphite. The current–voltage and power density characteristics have been measured and charge–discharge cycle tests of the MEA operation have been performed for an acidified vanadium electrolyte. The peak power density, charge–discharge cycle energy efficiency, and capacity utilization are comparable with those reported by leading research teams.

Technical carbon CH210 was processed by chemical reduction of the diazo derivative of anthraquinone for surface modification. The presence of anthraquinone groups on the carbon surface was confirmed by attenuated total internal reflection (ATR) IR spectroscopy. Carbon with the anthraquinone-modified surface was deposited on a glassy carbon support using a polymer binder. The behavior of the thus obtained catalyst in oxygen electroreduction in an alkaline medium was studied by the rotating disk electrode method. The kinetic characteristics of the reaction were determined: half-wave potential, limiting current, number of electrons, Tafel slope, exchange current, and charge transfer coefficient. Hydrogen peroxide is formed on the surface of the carbon–polymer composite at higher positive potentials than on technical carbon and glassy carbon electrodes. Therefore, the proposed material can be used as an effective electrocatalyst for this reaction.

An electrodynamic model of the redox sorption of oxygen from water on metal-ion-exchange nanocomposites’ (NCs) granular layers is proposed. It features a simultaneous description of the oxygen reduction process along the electrochemical and chemical routes. Due to the inhomogeneous oxidation of metal nanoparticles by oxygen, the granular layer of the NC ohmic resistance, which varies in height and time, is taken into account. The adequacy of the model was tested on a copper-containing NC.

Hydrogen-bromate flow battery is a promising hybrid current source for air-deficient environment that functions by electrocatalyzed reactions of hydrogen oxidation and aqueous LiBrO3 reduction. The flow cell consists of porous carbonaceous cathode, platinum catalyzed hydrogen oxidation gas diffusion anode, and separating proton exchange membrane. Performance of the hydrogen-bromate flow battery single cell has been optimized by varying the catholyte feed rate, LiBrO3 concentration in catholyte, hydrogen pressure, membrane thickness, amount of porous carbon at cathode, and Pt loading at anode. Shape of the I-V curve is characterized by a sharp maximum of current, which indicates passivation of one of the electrodes. Combination of conventional reference electrode and home-made thin-film Luggin capillary has been used to monitor separately the polarizations of both flow cell electrodes. Poisoning of platinum hydrogen oxidation electrocatalyst by bromine species, which permeated the membrane, is shown as a major source of performance losses of hydrogen-bromate flow battery at high power density. Hypothesis supported by experiments claims that the degree of the platinum electrocatalyst poisoning is determined by the balance between the rates of the bromine species supply to anode and their removal by liquid water that permeates the membrane. Use of thinner proton exchange membrane and thinner carbonaceous cathode is a prerequisite to achieving high power density of the cell at high current efficiency of the cathode process. At 40 °C, area-specific power reaches 0.74 W cm−2 at the level of catholyte utilization equal to 0.93.

Mesoporous polymer networks were prepared via the cross-linking radical copolymerization of non-toxic hydrophilic N-vinylpyrrolidone (VP) with triethylene glycol dimethacrylate (TEGDM) and poly(ethylene glycol) methyl ester methacrylate (PEGMMA) in bulk, using appropriate soluble and thermodynamically compatible macromolecular additives with a branched structure as porogens. The branched copolymers of various monomer compositions were obtained by radical copolymerization in toluene, controlled by 1-decanethiol, and these materials were characterized by a wide set of physical chemical methods. The specific surface areas and surface morphology of the polymer networks were determined by nitrogen low-temperature adsorption or Rose Bengal (RB) sorption, depending on the copolymer compositions and scanning electron microscopy. The electrochemical properties of RB before and after its encapsulation into a branched VP copolymer were studied on a glassy carbon electrode and the interaction between these substances was observed. Quantum chemical modeling of RB-VP or RB-copolymer complexes has been carried out and sufficiently strong hydrogen bonds were found in these systems. The experimental and modeling data demonstrate the high potency of such mesoporous polymer networks as precursors of molecularly imprinted polymers for the recognition of fluorescent dyes as nanomarkers for biomedical practice.

Heat-insulating mixtures developed on the basis of local raw materials are considered. Their properties are determined using Russian-made installations and their application at domestic metallurgical enterprises.

Acid-base flow batteries (ABFB) are a promising and environmentally benign class of flow batteries that utilize neutralization energy. Among the other flow batteries, ABFBs stand out with low cost and high solubility of the electrolytes and the possibility to harvest neutralization energy of acidic and alkaline wastewaters. However, the main ABFB issues, such as low power caused by discharge current limitation and low energy density, are limiting the possibility of their implementation. In this work, a novel two-membrane ABFB with two hydrogen electrodes was developed to overcome main ABFB issues. The proposed concept demonstrated high power density up to 6.1 mW cm-2 at 13 mA cm-2 . It was shown that battery performance was greatly limited by negative electrode overvoltage. Analysis of the voltage losses allowed to estimate main power losses and highlight the possible ways to its minimization.

The conditions for obtaining stable aqueous solutions of a lipophilic aminonitroxyl platinum complex, namely, e-amine-d-(4-amino-2,2,6,6-tetramethylpiperidine 1-oxyl)-a, f-bis(octanoato)-b, c-dichloroplatinum(iv), by means of its encapsulation into nanoparticles of copolymers of N-vinylpyrrolidone with triethylene glycol dimethacrylate with various monomer compositions and topologies were found. Aqueous solutions of the complex encapsulated into polymer particles were investigated by dynamic light scattering, the temperature dependence of nanostructure sizes was studied. Transmission electron microscopy established that the hybrid nanostructures are core—shell particles, in which the platinum complex forms small clusters (∼4 nm). The parameters of ESR spectra of aqueous dispersions indicate a high mobility of nitroxyl contained in hybrid nanostructures. Voltammetric measurements demonstrate a similarity of the redox reactions related to the free radical fragment of the aminonitroxyl PtIV complex and of the 4-acetylamino-2,2,6,6-tetramethylpiperidine 1-oxyl radical. Polymer products containing the platinum complex were studied by IR spectroscopy, TGA, and DSC. The cytotoxicity index (IC50) of the free and the encapsulated complex was determined for HeLa tumor cells. The cytotoxicity of the latter (IC50 47–205 nmol L−1) depends on the monomeric composition of the nanoparticles and the incubation time.