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This review is the third part of a series devoted to the use of organotin compounds as catalysts in a number of important industrial processes, such as (trans)esterification and polyurethane production. The third part covers the use of organotin compounds as catalysts for the vulcanization of blocked isocyanates and silicones.

The possibility of increasing the stability of the surface properties of polyethylene films treated in a high-frequency gas discharge plasma has been explored. It has been shown that, to weaken the effect of reversibility of surface properties, the plasma-treatment mode should meet two conditions: (1) the treatment time should not exceed the duration of the stage of formation of oxygen-containing groups in the surface layer of the polymer and (2) the temperature of the polymer during the treatment should be 70°C. The dependence of the specific discharge power on the polyethylene film thickness corresponding to the above conditions has been determined by calculation.

The possibility of direct etherification of a single primary hydroxy group of β-cyclodextrin with a series of alcohols and diols has been demonstrated. In the reactions with diols, dimeric β-cyclodextrin could be obtained, which are interesting from the practical viewpoint. The structure of the isolated compounds has been confirmed by 1H and 13C NMR spectra.

The results of an investigation of fission gas release from mixed nitride fuel after irradiation to maximum burnup 7.5% h. a. in 10 experimental FA in BN-600 are reported. It is shown that gas release commences at burnup >2% h.a. and increases with increasing burnup. The burnup dependence of gas release for mixed and uranium nitride fuel coincide quite well. The fission gas beneath the fuel-rod cladding consists of three basic components: xenon, helium, and krypton. The content of the remaining gases (N2, Ar, O2, CO2) does not exceed tenths of a percent. Xenon has the highest specific release, followed by helium and krypton. Helium has the highest relative release (>40%). Xenon and krypton have almost identical release not exceeding 20% for most of the investigated fuel rods. A higher release of fission gas is associated with either an increase of the fuel temperature (>1500°C) or features of fuel microstructure.

A stabler ignition and combustion of the premixed air/fuel mixture remains a topic of great interest due to the high demand for effective and efficient propulsion systems in aerospace applications. Extensive experimental studies and numerical simulations have been carried out to understand and develop ignition systems using cold and non-thermal plasma in microwave streamer discharges. Use of sub-critical streamer discharge allows to ignite air/fuel mixture by an external electric field whose intensity is significantly lower than the intensity required to induce air breakdown. Ignition and combustion of air/propane mixture by microwave sub-critical streamer discharge in low- and high-speed flows is studied experimentally. Qualitative (flame structure) and quantitative (size of combustion region, temperature distributions) characteristics of the flame zone are provided for different flow speeds and equivalence fuel/air ratios, and conditions of discharge initiation with metallic microwave vibrator are studied. The streamer discharge makes it possible to create multiple ignition points providing almost instantaneous ignition of entire volume of the mixture. The results show that the sub-critical streamer discharge can potentially be used in various applications providing more rapid and efficient combustion.

The authors present the second part of a series of reviews devoted to the use of organotin compounds as catalysts in a number of important industrial processes. In this part of the series, the use of organotin compounds in the processes of polyurethane formation is considered.

The authors present the first part of a series of reviews devoted to using organotin compounds as catalysts for a number of important industrial processes. These include (trans)esterification, polyurethane production, cold silicone vulcanization, and other processes of practical importance. In the first part of this series, the use of organotin compounds in (trans)esterification processes is considered.

This article presents the results of the investigation of the properties of phenol-formaldehyde resin, obtained using the phenol-replacing fraction. A two-step method was developed for phenol-replacing fraction separation from liquid pyrolysis products with a yield up to 15%, and this fraction was used in the phenol-formaldehyde resin synthesis. Then, a work was conducted for the removal of neutrals from the modified phenol-formaldehyde resin with organic solvents, n-hexane and benzene. As a result, benzene was defined as a more efficient solvent because it removed more aromatics, like ethers and substituted phenols, that cannot react and worsen the glue line water resistance. Benzene dissolved 3.2% weight of the resin, and n-hexane dissolved 2.5% weight. The removal of neutrals increased the water resistance coefficient by more than 60%, so neutrals have a considerable effect on the resin properties. The results can be used for production of resin from renewable feedstock with the similar properties with the traditional resin.

Sodium liquid glass silicate compositions modified with boron cluster anions [B10Cl10]2− or [B10H10]2− or SiO2 nanoparticles have been studied. It is shown that in the silicate matrix, the presence of the polyhedral anions results in nanoscale supramolecular structures formed due to their interaction with silanol groups of silicates. In the range of 20–600 °C, the TMA method is used to study the formation of supramolecular associates, as well as the deformation stability of the modified silicate matrix and the softening temperature of the modified polysilicates formed upon thermal exposure. Resumen: Se han estudiado composiciones de silicato de vidrio líquido de sodio modificadas con aniones poliédricos [B10Cl10]2− o [B10H10]2− o nanopartículas de SiO2. Se muestra que en la matriz de silicato, la presencia de los aniones poliédricos da como resultado estructuras supramoleculares a nanoescala formadas debido a su interacción con grupos de silicatos de silanol. En el rango de 20–600 °C, TMA se ha utilizado para estudiar la formación de asociados supramoleculares, así como la estabilidad a la deformación de la matriz de silicato modificado y la temperatura de reblandecimiento de los polisilicatos modificados formados tras la exposición térmica.

Pridopidine is an investigational drug in late stage development for the treatment of Huntington disease and originally postulated to act as dopamine stabilizer by modulating dopamine-dependent motor behavior. However, preclinical studies show pridopidine has highest affinity to sigma-1 receptors. Importantly, mediated by sigma-1 receptors, pridopidine has neuroprotective properties and enhances neuronal plasticity. The aim of our study was to determine the in-vivo the target engagement (receptor occupancy) of pridopidine at clinically relevant doses in healthy volunteers and Huntington disease patients. We used sigma-1 receptor-specific (S)-(-)-[18F]Fluspidine and dopamine D2/D3 receptor-specific [18F]Fallypride PET imaging to quantify the sigma-1 and dopamine D2/D3 receptor occupancy of pridopidine. Eleven male healthy volunteers (pridopidine 0.5 to 90 mg in six dose groups) and three male Huntington disease patients (pridopidine 90 mg) were studied twice before and 2h following single oral doses of pridopidine using S-(-)-[18F]Fluspidine PET (300 MBq, 0-90min p.i.). Distribution volume VT was quantified using kinetic modeling (One-tissue compartment model; metabolite correction). Four male healthy volunteers were studied twice using [18F]Fallpride PET (200 MBq, 0-210min p.i.) before and 2h after a single oral dose of pridopidine (90 mg). Binding potential BPND was assessed by the simplified reference model. Volume-of-interest analyses were performed. For each subject/tracer, the receptor occupancy was calculated by the Lassen plot analysis. In healthy volunteers, there was high sigma-1 receptor occupancy (87 to 91%) across all brain regions at doses ranging from 22.5 to 90 mg. The sigma-1 receptor occupancy was 43% at 1 mg pridopidine. In Huntington disease patients, very similar to healthy volunteers, at 90 mg pridopidine, there was high sigma-1 receptor occupancy (87±7%, n.s.). In contrast, in healthy volunteers, there was only negligible dopamine D2/D3 receptor occupancy (3±2%) at 90 mg pridopidine. We established a sigmoid-shaped dose/sigma-1 receptor occupancy relation (Hill equation) with Hill coefficient larger than 1 in healthy volunteers, suggesting a positive cooperative binding nature of the sigma-1 receptor. Using PET, we report for the first time in the living human brain that after a single dose of 90 mg, pridopidine acts as a selective sigma-1 receptor ligand showing near to complete sigma-1 receptor occupancy (~90%) but only minimal (~3%) dopamine D2/D3 receptor occupancy. Our findings provide significant clarification about pridopidine’s mechanism of action and support further use of the 45 mg bidaily dose to achieve full and selective targeting of the sigma-1 receptor in future clinical trials in Huntington disease and amyotrophic lateral sclerosis.

The compositions of alumoboro- and alumochromophosphate with a tetratomic alcohol, pentaerythritol, which is the component forming hydrogen and chemical bonds with the phosphate groups, are considered. The extremum dependence of the softening point on the concentration of pentaerythritol accompanied by a symbatic change in the moisture resistance is found. The heat and thermal resistance, oxygen index of the cured compositions, and bending strength of the composites reinforced by a basalt fabric are measured. The energy of the intermolecular bonds of the monomeric phosphate units with pentaerythritol is calculated, and computer modeling of the conformation of the complexes is performed. The higher chemical activity of alumochromophosphate in comparison with alumoborophosphate is determined.

Hard silicon carbonitride coatings are prepared using Ar and Ar (10 vol.% He) laser plasma from hexamethyldisilazane (HMDS) [(CH3)3Si]2NH and HMDS+benzene vapors. The coatings are characterized by infrared (IR), Raman, and X-ray photoelectron spectroscopies, transmission electron microscopy, and atomic force microscopy. The obtained coatings are amorphous and uniform in composition and over the film thickness. The microhardness of coatings synthesized on steel from a HMDS+ benzene mixture increases from 12 GPa to 18 GPa provided that other parameters remain constant.

Objective To determine whether urine S-adenosylmethionine (SAM) might be an indicator of chronic kidney disease (CKD). Methods We investigated urine levels of SAM and related metabolites (S-adenosylhomocysteine and homocysteine cysteine) in 62 patients (average age, 65.9 years) with CKD (stages II–V). Results Patients with stages III–V CKD stages have significantly decreased urine levels and SAM/S-adenosylhomocysteine ratio and also cysteine/homocysteine ratio in blood plasma (P Conclusions Our study results demonstrate that urine SAM is a potent biomarker for monitoring renal function decline at early CKD stages. Urine SAM testing confers an additional advantage to healthcare professionals in that it is noninvasive.

Composites of various composition are obtained by the solid-phase mixing of thermoplastic polyesters poly(3-hydroxybutyrate) and polylactide under conditions of shear deformation in the presence of poly(ethylene glycol) as a plasticizer. The thermophysical parameters in primary and secondary heating scans are measured. It is shown that the original polyesters are immiscible polymers. The degree of crystallinity and the enthalpy of melting of the polymers in the individual state and in blends are calculated. It is found that upon secondary heating the temperature transitions and the degree of crystallinity of these polymers change. The mechanical and rheological properties of the composites are investigated. A study of mold fungi resistance demonstrates that, unlike polylactide, poly(3-hydroxybutyrate) is a completely biodegradable polymer, while the biodegradability of the composites is determined by their composition.

The mechanical characteristics of bacterial cellulose (one of the most promising cellulose-based nanomaterials) fundamentally depend on its moisture content. It has been found that the effect of aqueous solutions of alkali metal chlorides on its strength and deformation properties is determined by the mobility of water molecules in the near coordination spheres of cation hydration shells.

The thermal and thermomechanical properties of polyurethanes based on isophorone diisocyanate and polyfurit crosslinked using various curing agents are studied by differential scanning calorimetry and dynamic mechanical analysis. Two transitions are observed on thermograms in the temperature range from –100 to +150°С. The first transition detected at a temperature below –60°С corresponds to the glass transition temperature of soft ester segments. A broad endothermic region (near 100°С) is related to the melting of crystal-like ordered structures formed by strong hydrogen bonding between hard segments. The relationship between the spectral-kinetic behavior of the photochromic compound introduced into the polymer matrix and the properties of the polyurethanes is investigated. The rate of photochemical transformations of the photochromic compound covalently bonded to the matrix may depend on the stage of the polymerization process at which it is introduced into the polymer.

It has been shown that two competing processes occur in a system of water glass (WG) silicates and [BnXn]2– (n = 10, 12; X = H, Cl) boron cluster anions (WG/[An]) in the range 100–200°C: the formation of a supramolecular structure due to cation–anion contacts of the silanol groups of the silicate with [An]'s at t ≤ 100°C and the condensation of the silanol groups of the silicate, resulting in the formation of polysiloxane chains (t ≥ 180°C). The difference in temperature conditions between these processes leads to inhibition of the silicate condensation process. The detailed structure of the silicate component of the WG/[An] systems has been studied as a function of [An] content.

The article presents the results of systematic measurements (2009−2017) of the total column abundances of methane (TC_CH4 ) and the column-averaged concentration (X_CH4 ) at the Antarctic station Novolazarevskaya. Solar radiation is recorded in the range 2990 – 3006 cm–1 using a diffraction spectrometer with 0.2 cm–1 resolution. The inverse task CH4 total column determining is achieved using the SFIT4 v0.9.4.4 code. The analysis shows that during the measurement period the average TC_CH4 was (3.4±0.8).1019 molecules/cm2 during the measurement period, and the average X_CH4 is (1663±34) ppbv. TC_CH4 trend is (4.5±2.2).1015 molecules/cm2 /month, and X_CH4 trend is (0.28 ± 0.11) ppbv/month. The average TC_CH4 values and trend at Novolazarevskaya are in good agreement with the measurements by the Brucker120HR instrument at the Arrival Heights station. Seasonal variations of atmospheric methane have the maximum in October–November and the minimum in May–July. The trends of surface methane concentrations at Sywa, the Halley station and the Amundsen-Scott South Pole station are 0.59 – 0.61 ppbv/month and exceed the trend of the column-averaged concentration at Novolazarevskaya and AIRS trends for the troposphere (0.24 – 0.32) ppbv/month, due to a decrease in the maximal values of TC_CH4 in the period after 2014. The closest agreement of X_CH4 variations at Novolazarevskaya with AIRS data is observed at the levels of 150–200 hPa. Significant semiannual harmonics varied with height are characteristic of CH4 variations according to the AIRS data. The interference of annual and semiannual harmonics leads to the appearance of two maxima in the seasonal variations of methane with relative position to each other varies with height. The statistical model is developed for all the series considered. It approximates the trend, annual and semi-annual components of CH4 oscillations.The authors have no competing interests.

The reactions of oligomeric aluminoborophosphates with hexamethylenediamine and pentylamine are studied, as are the properties of the obtained products which are polycomplexes with the participation of hydrogen bonds, which is confirmed by the results of quantum chemical calculations. The changes in the relaxation properties of the polycomplexes are determined by the softening and flow temperatures measured by thermomechanical analysis. It is shown that the modification of polyphosphates by primary amines under mild conditions leads to an increase in the water resistance of the obtained polycomplexes.

The possibility of synthesizing and processing incombustible materials based on oligomer and polymer oxides and their hybrids with organic and organoelement compounds at temperatures of 20–200°C is explored. Inorganic thermosetting plastics with a wide range of pour points (100–700°C) are synthesized. A more intense heat treatment can provide the formation of fireproof materials. Cast polymer–polymer blends of inorganic/organic polymers prepared by melt blending are studied. Possible areas of application of reinforced materials based on inorganic and hybrid impregnation composites are determined.

The synthesis of amphiphilic cationic β-cyclodextrin derivatives that contain the residues of some pharmacologically important acids have been proposed. The acid residues have been attached to cyclodextrins through the linker of different lengths at the primary hydroxyl groups. The hydrophobic fragments of palmitic acid have been attached to both the primary and secondary hydroxyl groups.

This article presents a method for fractionating and separating phenolic compounds from liquid pyrolysis products of lignocellulosic biomass by a three-stage method, in which up to 30% of phenolic compounds can be extracted. The composition of the phenol-substituting fraction was analyzed by the gas chromatography–mass spectrometry (GCMS) method. The isolated phenolic compounds were used in the synthesis of phenol–formaldehyde resins as a phenol-substituting fraction, with the replacement of 40% of the synthetic phenol in the recipe. Various molar ratios of phenol/formaldehyde and phenol/sodium hydroxide in the resin synthesis recipe were considered, as well as their influence on the strength of the adhesive joint and the proportion of free formaldehyde in the finished modified resin. The results of the studies showed that the optimal molar ratio of phenol/formaldehyde is 1:1.98, with a tensile strength of 1.63 MPa and a free formaldehyde fraction of 0.10% in the resin. The phenol/sodium hydroxide molar ratios considered in this paper did not show an optimal molar ratio, but a tendency to reduce the free formaldehyde content in the resin with a decrease in the introduction of an alkaline catalyst into the resin recipe was revealed, while the strength of the adhesive joint remains normal.

Thermal transitions have been determined for different ternary compositions of polylactide and poly-3-hydroxybutyrate with chitosan from their TGA and DSC data. The sorption capacity of the ternary mixtures for FeIII ion has been evaluated using the Langmuir model and found to increase with the chitosan content.

Hydrophobic derivatives of polysaccharides possess an amphiphilic behavior and are widely used as rheological modifiers, selective sorbents, and stabilizers for compositions intended for various applications. In this work, we studied the mechanochemical reactions of chitosan alkylation when interacting with docosylglycidyl and hexadecylglycidyl ethers in the absence of solvents at shear deformation in a pilot twin-screw extruder. The chemical structure and physical properties of the obtained derivatives were characterized by elemental analysis, FT-IR spectroscopy, dynamic light scattering, scanning electron microscopy, and mechanical tests. According to calculations for products soluble in aqueous media, it was possible to introduce about 5–12 hydrophobic fragments per chitosan macromolecule with a degree of polymerization of 500–2000. The length of the carbon chain of the alkyl substituent significantly affects its reactivity under the chosen conditions of mechanochemical synthesis. It was shown that modification disturbs the packing ability of the macromolecules, resulting in an increase of plasticity and drop in the elastic modulus of the film made from the hydrophobically modified chitosan samples.

The results of systematic (2003–2017) measurements of the total content and height-averaged relative volume concentration of CO at st. Novolazarevskaya with a spectrometer with a resolution of 0.2 cm–1 are presented. The inverse problem of determining the total content of CO as well as interfering gases (H2O and N2O) was solved using the SFIT4 software package. A data analysis indicated that during the measurements the average total CO content at st. Novolazarevskaya was (8 ± 2) 1017 molecules/cm2 and the height-averaged volume concentration was (37 ± 8) ppb. The resulting data were compared with variations in the total CO content at st. Arrival-Heights, MOPITT satellite data, and CO surface concentrations at st. Syowa. The maximum and minimum values of CO were observed in September and January–February, respectively. For all the data series considered, the trends are insignificant; in this case, an increased CO content was observed in 2010, and an increasing trend of the minimum values of CO was observed in recent years (2014–2017). Both stations (Novolazarevskaya and Arrival-Heights) are characterized by an excess of satellite data over ground-based measurement data (19% and 14%, respectively); here, a seasonal dependence of the deviation was observed with minimal deviations in December–January. Data of surface measurements of the total content at st. Novolazarevskaya and Arrival-Heights are rather well consistent, and the average deviation since 2010 was 2.4%. The average concentration of CO at st. Syowa (51 ppb) is higher than the height-averaged concentration at st. Novolazarevskaya. According to spectral, wavelet, and composite analyzes, all data series considered include oscillations in the range of 6–45 months with almost identical periods and phase relationships.

To optimize heating conditions during the Thellier procedure and to improve the reliability of paleofield determination, thermal stability experiments with titanomagnetite and titanomaghemite obtained by laboratory heating were conducted. The experiments were performed on P72/2 and P72/4 basalts of the rift zone of the Red Sea that contain titanomagnetite with a concentration of the magnetite component equal to (44.7 ± 3.9)% and (46 ± 5)%, respectively. It has been shown that the single-phase oxidation process prevails in annealing of titanomagnetite for 10 hours in a temperature range of 290–410°C in air. An increase in the annealing temperature up to 460–535°C means that single-phase oxidation is replaced by oxi-exsolution. The temperature range of thermal stability of the single-phase oxidized titanomagnetite expands with the degree of oxidation. In particular, at an oxidation state close to 0.9, titanomaghemite is stable up to temperatures of 410–460°C. The use of the Thellier technique for studying the properties of the chemical remanent magnetization of single-phase oxidized titanomagnetite with an oxidation state above z ≥ 0.6 is limited to approximately 20% of its value. It is possible to stabilize the single-phase oxidized state of titanomagnetite at temperatures above 460°C and thereby to improve the quality of CRM research using the Thellier method by adjusting the value of the oxygen partial pressure.

The results of experimental studies of combustion of propane–air gaseous mixture when it was ignited by a microwave discharge have been described. The mixture with different propane content fills a sealed radio-transparent tube placed along the axis of a focused linearly polarized quasi-optical microwave beam at atmospheric pressure. Multi-point ignition of the mixture is carried out near one end of the tube by a pulsed microwave discharge with a surface-developed streamer structure. The growth of gas pressure in the tube as propane burned was recorded in the experiments. The microwave pulse energy being invested in high-temperature discharge plasma has been estimated in them. The minimum percentage of propane in the mixture at which the microwave discharge ignites it has been determined in experiments. The time dependence of the pressure increase in the tube as the propane burns determines the combustion process dynamics.

There have been consistent efforts in developing more efficient combustion for propulsion systems. Ignition and combustion control using cold and non-thermal plasma in microwave discharges have become a major topic of interest. In this study, a microwave subcritical streamer discharge is used to initiate ignition and combustion of premixed air/fuel mixture in a long cylindrical tube. The streamer discharge is arising on the internal surface of the dielectric tube using a passive vibrator in a single pulse regime at atmospheric pressure and temperature. The propagation speed of the combustion front in the quartz cylindrical tube filled by the air/propane mixture is analyzed experimentally and numerically. The streamer discharge creating a multitude of ignition points provides practically instantaneous ignition of the mixture in the entire volume. The speed of streamer induced combustion front has been shown to be higher compared to that initiated by a spark. Increasing the length of streamer discharge leads to increasing the flame propagation speed. The combustion efficiency has also been shown to be higher when using the microwave streamer ignition.

The development of a specific inflammation in mice that had been infected by two influenza virus strains, A/chicken/Kurgan/5/2005 (H5N1) and A/Hamburg/2009 MA (H1N1), was studied. We investigated the effect of a non-toxic lipopolysaccharide from Rhodobacter capsulatus PG on the survival and body weight of the mice, production of IgG antibodies, and the induction of pro- and anti-inflammatory cytokines in blood serum. The administration of the R. capsulatus PG lipopolysaccharide was shown to induce interferon- synthesis, both in healthy and influenza A virus-infected mice, and to promote production of antiviral antibodies in the blood of the influenza-infected animals.

The polycondensation of silicates of sodium liquid glass containing silanol groups is studied by thermogravimetry analysis, differential scanning calorimetry, thermomechanical analysis, and IR spectroscopy. The studies are carried out in a temperature range of 100–600°C. The degree of polycondensation depending on the thermolysis conditions is estimated.

—Spin labeling EPR spectroscopy was used to study the structural and conformational characteristics of human serum albumin and human erythrocyte membranes under normal conditions and with symptoms of heart failure. 5-Doxyl stearic acid and 16-doxyl stearic acid were used as spin labels, whose paramagnetic NO fragments are bound to different sites of the hydrocarbon chain. The EPR spectra of 16-doxyl stearic acid indicate that in the physiological temperature range serum albumin molecules are characterized by several types of fatty acid binding sites, which differ in parameters of spin-label rotational diffusion. This distribution of fatty-acid binding sites was typical for the blood serum of all patients who participated in our study, regardless of deviations from the normal blood parameters. The microviscosity of erythrocyte membranes from patient blood was measured using both 5-doxyl stearic and 16-doxyl stearic spin labels, whose paramagnetic fragments are located at different depths inside the lipid bilayer. It was found that in patients with an increased erythrocyte distribution width, the membrane lipid microviscosity is statistically significantly higher than under normal conditions.

A validated approach to determine various methionine cycle metabolites (S-adenosylmethionine, S-adenosylhomocysteine, and methylthioadenosine) in human blood plasma is offered. The approach is based on solid-phase extraction (with grafted phenylboronic acid) and derivatization with chloroacetaldehyde followed by ultra-performance liquid chromatography with fluorescence detection. We used a 100 × 2.1 mm × 1.8 μm C18 column for the selective separation of analytes. Chromatographic separation was achieved with gradient elution of acetonitrile (flow rate 0.2 mL/min) from 2 to 20%. The eluent was initially composed of 10 mM KH2PO4 with 10 mM acetic acid and 25 μM heptafluorobutyric acid. The total analysis time was 11 min. Validation of the method included detection of the limit of detection (2 nM), limit of quantification (5 nM), accuracy (97.2–101%), and intra- and interday precision (2.2–9.0%). Analysis of plasma samples from healthy volunteers revealed that the average levels of S-adenosylmethionine, S-adenosylhomocysteine, and methylthioadenosine were 93.6, 20.9 and 14.8 nM, respectively.

Na-LTA membranes have been synthesized on porous nickel supports by in situ crystallization from a true solution. K-LTA and Ca-LTA membranes have been prepared from Na-LTA membranes by ion exchange in 1 M KCl and CaCl2 solutions, respectively. The formation of the LTA structure, its preservation during ion exchange, and achievement of nearly 100% replacement in the near-surface layer of the zeolite membranes have been proven by means of XPD and SEM-EDX. All the zeolite membranes synthesized have been tested in pervaporation of isopropanol–water, ethanol–water, and methanol–water mixtures containing 10 wt % water. It has been found that the mass flux of alcohol does not depend on the nature of alcohol or zeolite cation if the kinetic diameter of alcohol molecule is greater the effective diameter of zeolite pores. A new method for evaluating of the mass flux through nonzeolite pores based on pervaporation data has been proposed. The estimated mass flux through nonzeolite pores for all the zeolite membranes tested is 15 ± 3 g m−2 h−1 which is 1.6 to 7.6% of the total transmembrane mass flux depending on the alcohol chosen.

Domestic and foreign literature on methods for obtaining graphene and its derivatives [graphene oxide (GO) and reduced GO] as representatives of the family of 2D layered materials is analyzed. Particular attention is paid to GO. Great potential of post-synthetic modification as well as unique properties of the material and its derivatives make them promising for a variety of applications including biomedicine, ecology, optoelectronics, etc. Chemical and physical methods for the reduction of GO to obtain graphene-like materials similar in structure and properties to pure graphene obtained by direct mechanical cleavage are considered. Functionalization strategies of graphene materials are discussed. The preparation of hydro- and organogels as well as Pickering emulsions from graphene derivatives as precursors of porous monoliths are considered. The formation of aerogels based on graphene materials and methane adsorption on these porous structures are discussed. Basic information about hybrid materials containing graphene derivatives and metal-organic frameworks is given and their adsorption characteristics with respect to methane are evaluated. Covalent and noncovalent interactions in graphene – porphyrin hybrids are considered from the standpoint of formation of porphyrin architectures on the surface of graphene materials. Examples of the use of porphyrin – graphene composite materials in photo- and electrocatalysis, fuel cells and gas separation membranes are given. The bibliography includes 243 references.

Bacterial cellulose is a product of the vital activity of some types of bacteria. In contrast to plant cellulose, it is characterized by high purity, strength, and elasticity. Together with nontoxicity and biocompatibility, these properties make bacterial cellulose to be applicable in biotechnology, medicine, and production of composites as a reinforcing component. The nanoscopic sizes of the structural units of bacterial cellulose provide it with a large specific surface area and, as a consequence, a pronounced dependence of many properties of a material on surface interactions with an environment. This review is devoted to discussing the structure and mechanical properties of bacterial cellulose, with especial attention being focused on its behavior in the presence of water and aqueous solutions. “Bacteria make no mistakes…” S. Gandlevskii

Objective To evaluate the association of S-adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH) in urine with chronic kidney disease (CKD). Methods Case-control study including 50 patients with CKD and 20 healthy volunteers. Results SAM level and SAM/SAH ratio in urine were significantly lower in patients than in control individuals (P Conclusion CKD is associated not only with the decline in the SAM level but also with the decrease in the SAM/SAH ratio in urine. Thus, use of the urinary SAM/SAH ratio as a noninvasive diagnostic indicator of renal function seems promising.

The results of systematic (2003–2017) measurements of the total content and the volume mixing ratio of CO at Novolazarevskaya station with a spectrometer with a resolution of 0.2 cm– 1 are presented. The inverse problem of determining the total CO content, as well as interfering gases (H2O and N2O), was solved using the SFIT4 software package. Data analysis showed that over the measurement period the average total CO content at Novolazarevskaya amounted to (8 ± 2) 1017 molec/cm2, and the average volume mixing ratio amounted to (37 ± 8) ppb. The obtained data are compared with variations in the total content of CO in Arrival-Heights station, with MOPITT satellite data, as well as with surface values of CO concentration at Syova station. The maximum values of CO are observed in September, the minimum — in January–February. For all the considered series, the trends are insignificant, while there are periods of increased CO content (2010). In recent years (2014–2017) there is a tendency towards an increase in the minimum values of CO. For Novolazarevskaya and Arrival-Heights satellite data are characterized by the excess of over ground data, amounting to 19% and 14%, respectively, while there is a seasonal dependence of the deviation with the minimum in December–January. Surface measurements of the total CO content are in fairly good agreement at Novolazarevskaya and Arrival-Heights, and since 2010 the average deviation is 2.4%. The average value of the concentration of CO on Syova 51 ppb is higher than the average volume mixing ratio at Novolazarevskaya. According to the spectral, wavelet and composite analyzes, in all the considered series there are oscillations in the range of 6–45 months with closely coinciding periods and phases.

Amphiphilic conjugates were obtained containing fragments of pharmacologically important monocarboxylic aromatic acids, which are of interest for biomedical research, have been obtained basing on 6-O-tert-butyldimethylsilyl β-cyclodextrin derivative.

Regioselective mono- and diphosphorylation of 1,4:3,6-dianhydro-d-sorbitol containing two hydroxyl groups differing in steric availability has been studied. The nature of the amine acting as activator and acceptor of hydrogen chloride have had significant impact on the direction of phosphorylation and the structure of the resulting products.

We report a four-component mixture comprising bisstyryl dyes, HP-β-CD and CB[7] that undergoes self-sorting in aqueous solution based on ion–dipole, electrostatic, charge–transfer interactions, as well as the hydrophobic effect. The formation of 1:1 and 1:2 complexes between the bisstyryl guests and HP-β-CD, CB[7] has been confirmed by optical and NMR spectroscopy as well as ESI-MS data. The studied supramolecular systems are stimuli responsive. Thus, protonation of bisstyryl dye based on pyridine heterocyclic residue leads to the destruction of its complexes with HP-β-CD. Whereas, complex of the bisstyryl dye with CB[7] based on N-methylpyridinium moiety can be replaced by Ba2+ cation. The work demonstrates that HP-β-CD and CB[7] are molecular containers suitable for the creation of stimuli-responsive and self-sorting systems.

We have studied the EPR of Mn2+ ions in three samples of cubic nano-ZnS made by different technologies and having different nanoparticle sizes. Manganese occurs in the samples as an uncontrolled impurity. The EPR spectra can be described by two components: the spectrum of the Mn2+ in a cubic environment (Mn2+(C)) with parameters g = 2.0022 ± 0.0002, A = (–63.5 ± 0.5)·10–4 cm–1, 0 b4 ≥ 3.5·10–4 cm–1; and the spectrum of the Mn2+ ion associated with a planar lattice stacking fault (Mn2+ (F)), with parameters g = 2.0022 ± 0.0002, A = (–63.5 ± 0.5)·10–4 cm–1, $$ {b}_2^0 $$ = (–36 ± 1)·10–4 cm–1. The ratio of the number of centers Mn2+(C)/Mn2+(F) is 2.1:1 for sample 1 and 1.7:1 for samples 2 and 3. Planar stacking faults are typical lattice faults for cubic nano-ZnS. EPR of the Mn2+ ions lets us monitor the presence of these ions.

A model developed for the description of experimental data on heterogeneous nucleation in disperse systems with metastable dispersed phases is applied to the case of ice nucleation in a water emulsion in decane under methane pressure . Activity spectra are obtained for ice-forming particles in the water–decane–methane system. The frequency of ice nucleation on these particles is calculated. Activities of ice- and clathrate-forming particles in this system are compared. It is shown that small amounts of active particles incorporated into the system from an environment can have a significant effect on ice nucleation.

In this work the model which allowes to receive information about characteristics (number, content and relative activity) of heterogeneous nucleation centers in dispersed systems with metastable di...

A subcritical microwave streamer discharge is used to initiate ignition of premixed air/fuel mixture. The streamer is arising on the internal surface of the dielectric tube using a passive vibrator in a single-pulse regime at atmospheric pressure and temperature. The propagation speed of the combustion front in the quartz cylindrical tube filled by the air/propane mixture is analyzed numerically. The performed studies showed that the streamer discharge, which creates a multitude of ignition points, provides practically instantaneous ignition of the mixture in the entire volume of the tube, where the streamers reach. The results of numerical simulation are compared with the experimental data. Increasing the length of streamer discharge leads to increasing the flame propagation speed.

A subcritical microwave streamer discharge is used to initiate ignition of premixed air/fuel mixture. The streamer is arising on the internal surface of the dielectric tube using a passive vibrator in a single-pulse regime at atmospheric pressure and temperature. The propagation speed of the combustion front in the quartz cylindrical-tube filled by the air/propane mixture is analyzed experimentally. Ignition of lean fuel mixtures by a streamer has been demonstrated at the atmospheric pressure. The performed studies showed that the streamer discharge, which creates a multitude of ignition points, provides practically instantaneous ignition of the mixture in the entire volume, where the streamers reach. Measurements have shown that the front velocity increases with an increasing discharge length. The speed of streamer-induced combustion has been shown to be higher compared with that initiated by a spark. The combustion efficiency has also been shown to be higher when using the microwave streamer ignition.

The solvent-free synthesis of allyl-substituted chitosan derivatives through reactive co-extrusion of chitosan powder with allyl bromide at shear deformation was performed. For the structural characterization, FTIR and NMR methods were employed. The results were confirmed by chemical analysis. The total content of allyl substituents from 5 to 50 per 100 chitosan units as a function of the component ratio in the reactive mixtures was revealed. Carrying out the reaction without any additives leads to the selective formation of N-alkylated derivatives, whereas in the presence of alkali the ethers of chitosan were preferentially formed. The results suggest that the proposed approach allows significantly higher yield of products to be obtained at high process speeds and significantly lower reagent consumption as compared with the liquid-phase synthesis in organic medium. The synthesized unsaturated derivatives are promising photosensitive components for use in laser stereolithography for fabrication of three-dimensional biocompatible structures with well-defined architectonics.

Products are obtained from interaction between oligomeric aluminoborophosphate (ABP) and aniline, both complexes based on hydrogen bonds, as confirmed with IR spectroscopy and quantum chemical calculations. Nitrogen and hydrogen atoms of an amino group in aniline form hydrogen bonds with hydrogen and oxygen atoms of a phosphate group in ABP, respectively, with a total energy of 14.2 kcal/mol. Aniline, when added to ABP surrounded with a shell of water molecules, displaces two water molecules from the surface of the chain. The energy gain is 9.1 kcal/mol. IR spectroscopy data show that there are strong donor-acceptor interactions between water molecules and aluminum and phosphorus atoms of ABP in the solid-state polycomplex sample. The thermoplastic oligomeric complexes leads to an increase in the softening temperature and fluidity with an increase in an amount of aniline. This means that polyoxide inorganic polymer (metal phosphate) is possible to be modified with a monofunctional amine under “mild” conditions. We showed that the water resistance of the polycomplex is greater than that of ABP.

We report here on dipolar coupling of spin waves propagating as guided modes of adjacent yttrium iron garnet stripes. Three stripes are placed parallel to each other and separated by gaps that are small enough to provide nearest-neighbor coupling. The origin of the coupling is the dipole field of the precessing magnetization vector. The micromagnetic numerical simulation, yielded spectra of spin waves through the magnonic structure. Analysis of those spectra revealed that the lateral structure can be used as a functional unit in planar magnonic networks – they can be utilized as a directional coupler, spin-wave multiplexer, or microwave power divider. Using Brillouin light scattering spectroscopy, we experimentally demonstrated spin-wave transport along the lateral stripes. We were able to control the spin-wave routing between the stripes by varying the bias angle of the magnetic field.

The antioxidant effect of dinitrosyl iron complexes (DNICs) was studied in various model systems. DNICs with glutathione ligands effectively inhibited Cu2+-induced peroxidation of low density lipoproteins (LDL). The antioxidant effect of DNICs with phosphate ligands and free reduced glutathione (GSH) was less pronounced. In addition, DNICs with glutathione suppressed the formation of reactive oxygen species during co-oxidation of lecithin liposomes and glucose. Free radical oxidation in this system was induced with a lipophilic azo initiator and evaluated by luminol-dependent chemiluminescence. NO sharply stimulated chemiluminescence during co-oxidation of glucose and liposomes, thus suggesting the formation of potent oxidants under these conditions. Glutathione DNICs scavenge the superoxide radical anion generated in the xanthine-xanthine oxidase system. Superoxide production was assessed by lucigenin-dependent chemiluminescence and electron paramagnetic resonance (EPR) spectroscopy. Chemiluminescence revealed the dose-dependent character of antiradical effect of glutathione DNICs; moreover, these complexes turned out to be more efficient than GSH. EPR spectra of the adducts of the DEPMPO spin trap with free radicals suggest that the interaction of glutathione DNICs and superoxide does not result in the formation of the thiyl radical of glutathione. Here we propose a mechanism of the antioxidant action of glutathione DNICs, suggesting that unstable intermediate complexes are formed upon their interaction with superoxide or lipid radicals. Further, as a result of intramolecular rearrangement, these intermediates decompose without the free radical as the by-products.V razlichnykh model'nykh sistemakh issledovali antioksidantnoe deĭstvie dinitrozil'nykh kompleksov zheleza (DNKZh). Pokazano, chto DNKZh s glutationovymi ligandami (GS-DNKZh) éffektivno ingibiruiut indutsirovannoe ionami Cu2+ perekisnoe okislenie lipoproteinov nizkoĭ plotnosti (LNP). Antioksidantnoe deĭstvie DNKZh s fosfatnymi ligandami i svobodnogo vosstanovlennogo glutationa (GSH) bylo menee vyrazhennym. Krome togo, GS-DNKZh podavliaiut obrazovanie aktivnykh form kisloroda pri sookislenii letsitinovykh liposom i gliukozy. Svobodnoradikal'noe okislenie v étoĭ sisteme indutsirovali lipofil'nym azoinitsiatorom (AIBN) i otsenivali s pomoshch'iu liuminol-zavisimoĭ khemiliuminestsentsii. NO rezko stimuliroval khemiliuminestsentsiiu pri sookislenii gliukozy i liposom, chto ukazyvaet na obrazovanie v étikh usloviiakh sil'nykh okisliteleĭ. Takzhe ustanovleno, chto GS-DNKZh perekhvatyvaiut superoksidnyĭ radikal (O2 •−), generiruemyĭ v sisteme ksantin-ksantinoksidaza. Produktsiiu O2 •− otsenivali metodami liutsigenin-zavisimoĭ khemiliuminestsentsii i spektroskopii élektronnogo paramagnitnogo rezonansa (ÉPR). S ispol'zovaniem khemiliuminestsentsii pokazano, chto antiradikal'noe deĭstvie GS-DNKZh bylo dozozavisimym, prichem éti kompleksy byli bolee éffektivny, chem GSH. Analiz spektrov ÉPR adduktov spinovoĭ lovushki DEPMPO c svobodnymi radikalami pozvoliaet zakliuchit', chto pri vzaimodeĭstvii glutation-soderzhashchikh DNKZh i O2 •− ne obrazuetsia tiil'nogo radikala glutationa. Predlozhen mekhanizm antioksidantnogo deĭstviia GS-DNKZh, predpolagaiushchiĭ obrazovanie pri ikh vzaimodeĭstvii s O2 •− ili lipidnymi radikalami nestabil'nykh promezhutochnykh kompleksov. Dalee v rezul'tate vnutrimolekuliarnoĭ peregruppirovki éti intermediaty raspadaiutsia bez obrazovaniia svobodnoradikal'nykh produktov.