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Intermicrobial interactions play a key role in the regulation of microbial populations and the colonization of various ecological niches. In the present study, we assessed the effect of cell-free supernatants (CFSs) from the vaginal isolates Corynebacterium amycolatum ICIS 53 and Corynebacterium amycolatum ICIS 82 on urogenital test strain biofilm formation of Staphylococcus aureus. Our studies showed that the CFSs of both C. amycolatum strains significantly reduced biofilm formation and disrupted preformed S. aureus biofilms. Pretreatment with C. amycolatum ICIS 53 or C. amycolatum ICIS 82 CFSs decreased the cell surface hydrophobicity and exopolysaccharide production of all the test S. aureus isolates. The scanning electron microscopy (SEM) results showed that the CFSs of corynebacteria caused the S. aureus biofilms to be small clusters scattered across the surface, there were no fibres or adhesions between cells, and the cell membrane was not damaged. Treatment of preformed biofilms with CFSs from both C. amycolatum strains resulted in a flat, scattered, and unstructured architecture. The S. aureus cell membrane was damaged. GC‒MS analysis of the CFS of C. amycolatum ICIS 53 revealed the presence of 22 chemical compounds, including long-chain fatty alcohols, esters, fatty acids and heterocyclic pyrrolizines and pyrazoles, that, according to the literature, exhibit a wide range of biological activities. The results of the present work provide insight for the study of Corynebacterium microorganisms as a source of multifunctional bioactive compounds, which may find promising applications in the medical, biotechnological and pharmaceutical industries. [ABSTRACT FROM AUTHOR]

In the paper, the structure of the hydrogen–helium upper atmosphere of hot Jupiter depending on the flux of extreme ultraviolet radiation from the host star has been studied. An aeronomic 1D model based on the approximation of single-fluid multicomponent hydrodynamics has been used for calculations. The numerical model has taken into account chemical reactions, heating-cooling processes, tidal action from the star, diffusion, and thermal conductivity. Calculations have been performed for hot Jupiter HD 209458b. In all the obtained solutions, a transonic planetary wind has been formed leading to a hydrodynamic outflow of the atmosphere. Taking into account the tidal force has led to increase the outflow of atmosphere by 2.5 times compared to the case, in which only the gravity of the planet has been considered. The dependence of the mass loss rate of the planet on the flux of extreme ultraviolet radiation has been found to be nonlinear. This may be due to a different dominant mechanism of conversion of absorbed radiant energy in the upper atmosphere within the limits of weak and strong ultraviolet fluxes. [ABSTRACT FROM AUTHOR]

In the paper, the impact of a stellar flare on the upper atmosphere of hot Jupiter has been studied using 1D aeronomic model. The atmosphere has been assumed to have a hydrogen–helium chemical composition, and calculations have been carried out for hot Jupiter HD 209458b. We have examined single and repeated flares, in which the flux of hard UV radiation has increased by 10, 100, and 1000 times compared to the quiescent state of the star. The active phase of the dynamic response of the atmosphere has lasted 12–15 h after the flare, and the characteristic period of relaxation to the initial state has been about a day. From the obtained results, it follows that the flare activity of solar-type stars has not had a significant effect on the evolution of the planetary atmospheres of hot Jupiters. However, the interpretation of transit observations of the disturbed atmospheres of hot Jupiters will make it possible to separate from each other the observational effects associated with the interaction of stellar flares and coronal mass ejections with the upper atmospheres and envelopes of these planets. This will make it possible to determine more accurately the parameters of the stellar wind and coronal mass ejections of solar-type parent stars. [ABSTRACT FROM AUTHOR]

The structural perfection of a HgCdTe epitaxial layer with a minimum number of extended structural defects is ensured by the molecular beam epitaxy method and by the growth on substrates matched to the crystal lattice parameter. CdZnTe (211)B substrates (Orion Association, Moscow, Russia) have a total thickness variation (TTV) of less than 1.5 μm and a surface roughness of Ra = 0.45 nm (rms = 0.58 nm). [ABSTRACT FROM AUTHOR]

Human rhinovirus picornain 3C is a high-value commercial cysteine protease, which is widely used to remove affinity tags and fusion proteins during the purification of the target proteins. A variant of rhinovirus A28 picornain 3C produced in this study is not annotated in the NCBI databases, shares 79% sequence identity in the PDB, and was not previously used in the protein engineering. A protocol was developed for the isolation and purification of the protein to use it in structural studies. The initial crystallization conditions were found. The determination and analysis of the structure of rhinovirus A28 picornain 3C will provide new possibilities for performing basic research on the evolution of proteolytic enzymes and for the design of the optimal variant of this protease. [ABSTRACT FROM AUTHOR]

The chemical composition, surface morphology, and electrochemical properties of Ti–Al–V alloys in the initial state and after irradiation with О+ ions and alternating irradiation with О+ and N+ ions differing in the irradiation dose of N+ ions are studied. Under irradiation with О+ ions, the active oxidation of Ti atoms is shown to occur, which is accompanied by the formation of titanium oxides and hydroxides. In the course of subsequent irradiation with N+ ions, the accumulation of nitrogen and formation of titanium nitride TiN are found to occur to lower concentrations as compared to those observed without the preliminary irradiation with О+ ions. It is assumed that this is due to the higher chemical activity of oxygen with respect to titanium atoms, as compared to that of nitrogen. [ABSTRACT FROM AUTHOR]

The paper presents a one-dimensional aeronomic model of hydrogen–helium upper atmospheres of hot giant exoplanets based on the approximation of single-fluid multicomponent hydrodynamics. Chemical reactions and heating–cooling processes are taken into account. Typical cases of a hot Jupiter and a warm Neptune are considered as an example of the application of the model. Calculations were carried out for various values of the gas pressure at the photometric radius of a planet. In the solutions obtained, the transonic planetary wind is formed, which leads to a hydrodynamic outflow of the atmosphere with mass loss rates of about 1010 and 109 g/s for a hot Jupiter and a warm Neptune, respectively. At the same time, the outer layers of the atmosphere of a hot Jupiter become completely ionized, while the atmosphere of a warm Neptune mainly consists of neutral gas. In some variants of the hot Jupiter model, instability develops in the deep layers of the atmosphere, which may result in the formation of a specific cloud layer. [ABSTRACT FROM AUTHOR]

The cadmium mercury telluride solid solution is one of the most important infrared photoelectronic materials in the world. In obtaining this compound, molecular beam epitaxy has a number of advantages over other methods. At the same time, this solid solution is quite demanding on the pre-growth processing of substrates. In this study, the polishing processes are the primary development in mastering the production of cadmium mercury telluride (211) wafers. A roughness value of ~1 nm is obtained. [ABSTRACT FROM AUTHOR]

It is known that swelling of Nafion polymer membrane in water is accompanied by unwinding of polymer fibers into the bulk of the surrounding liquid. This effect is controlled by the deuterium content in water. In this paper, we report the results of studying the adsorption dynamics of methylene blue (MB) dye on the Nafion surface for MS solutions based on natural water (deuterium content 157 ppm, unwinding effect occurs) and based on deuterium-depleted water (DDW; deuterium content 3 ppm, unwinding effect is absent). In addition, we investigated the water desorption dynamics upon drying a Nafion polymer membrane after soaking in an MB solution based on natural water and DDW. It turned out that the MB adsorption rate in MB solutions based on natural water is lower than in the DDW-based MB solutions. Finally, the water desorption upon drying was found to be accompanied by a change in the Nafion absorption spectrum. Specifically, upon water desorption, the low-frequency band of the doublet in the range from 600 to 800 nm in the absorption spectrum of Nafion with MB particles on its surface undergoes transformation with a shift to the short-wavelength region. This transition occurred earlier for Nafion soaked in a DDW-based MB solution. The found effects are related to the retardation of diffusion processes in the layer of polymer fibers unwound near the membrane surface. Thus, changing the deuterium content in the aqueous solution in which the polymer membrane is swollen by very small steps (from 3 to 157 ppm), one can control the dynamics of adsorption and desorption processes. [ABSTRACT FROM AUTHOR]

A PdAg deposit containing ~ 25 at.% Ag is obtained by the electrochemical codeposition from an aqueous solution of Pd and Ag sulfates (Au support, 0.5 M H2SO4). The deposit is characterized by means of various physical, physicochemical, and electrochemical methods. The PdAg deposit demonstrates the ~ 2 times higher specific activity (per the electrochemically active surface area (EASA) of Pd) in the formic acid oxidation reaction (FAOR) as compared with the individual Pd deposit prepared under the same conditions. The effect of silver additions on the palladium activity depends on many factors. The corrosion stability of PdAg is studied in 0.5 M H2SO4 solution based on the overall cyclic voltammograms (CVAs) and also on anodic and cathodic half-cycles in the region E = 0.3 − 1.25 V (vs. reversible hydrogen electrode (RHE)). The electrochemical estimates are compared with the results of direct analytical determination of dissolution products in solution after anodic polarization of deposits. The total amounts of Pd dissolved substantially increase with incorporation of Ag, which is associated, first of all, with the considerable increase in the EASA; at the same time, the specific dissolution of Pd also substantially increases. The possible factors determining the active dissolution of PdAg deposits are discussed; in particular, the specific mechanism of their dissolution via silver adatoms is proposed. [ABSTRACT FROM AUTHOR]

The purpose of this study was to evaluate the probiotic characteristics and safety and to study the antifungal activity of C. amycolatum ICIS 9 and C. amycolatum ICIS 53 against Candida spp. The probiotic potential and safety properties were assessed by standard parameters. Both strains showed good survival at pH 3 for 3 h and high tolerance to 0.3% bile salts after 4 h of incubation. The indicators of hydrophobicity, autoaggregation, and surface tension for ICIS 9 were 89.43% (n-hexane) and 73.96% (xylene) and ranged from 13.13 to 39.86% and 34.27 mN/m, respectively. For ICIS 53, they were 59.95% (n-hexane) and 45.68% (xylene), from 35.58 to 51.53% and 32.40 mN/m, respectively. The strains ICIS 9 and ICIS 53 exhibited varying levels of coaggregation with all eight examined bacterial pathogens. The ICIS 9 strain was resistant to amikacin, amoxicillin, clarithromycin, chloramphenicol, ciprofloxacin, and gentamycin. ICIS 53 was resistant only to ciprofloxacin. The cell-free supernatant of strains ICIS 9 and ICIS 53 showed good antimicrobial and antibiofilm activity against 10 pathogenic vaginal and intestinal isolates of Candida spp. The CFS of ICIS 9 was more active against intestinal isolates, and the CFS of ICIS 53 showed good antimicrobial activity against vaginal isolates while inhibiting the growth of 2 out of 5 Candida spp. isolated from the intestine. Both of the strains were capable of reducing the biofilm formation of Candida fungi. In the case of the vaginal isolates of C. krusei V1, the results showed that the inhibition levels of ICIS 9 and ICIS 53 were 36.75 and 11.4%, respectively. In the case of C. albicans (V2, V3, V7, and V8), the inhibition of biofilm formation was no more than 7.07%. ICIS 9 and ICIS 53 also significantly inhibited biofilm formation of C. krusei 2613 intestinal isolates by 42.75 and 41.87%, respectively, with ICIS 9 inhibiting biofilm formation of C. albicans (2607, 2311, 2615, and 2615) from 3.38 to 15.69% and ICIS 53 from 5.95 to 23.48%. None of the strains showed DNase, haemolytic, or gelatinase activities. The results obtained revealed that ICIS 9 and ICIS 53 have safe properties and have the potential to be developed as probiotics. [ABSTRACT FROM AUTHOR]

Biofilm formation is an important factor in the development of antibiotic resistance and chronic infection. In this study, we demonstrated that the cell-free supernatant of vaginal isolates of C. amycolatum caused a reduction in biofilm formation, destroyed the preformed biofilms, altered the cell surface properties and reduced the production of exopolysaccharides in clinical isolates of P. aeruginosa и Kl. pneumoniae. Microscopic observations showed that P. aeruginosa and Kl. pneumoniae biofilm formed small clusters scattered over the surface after treatment with cell-free supernatant of C. amycolatum ICIS 99, in contrast to the dense aggregates observed in controls, as well as the flat, scattered, and unstructured biofilm architecture after treatment of preformed biofilms cell-free supernatant. The cells were flat and relatively unstructured. Based on these results, we hypothesize that C. amycolatum likely produces secondary metabolites with antimicrobial activity and utilizes a similar mechanism of action to bacteriocins and/or biosurfactants. The data obtained open the prospect of studying the metabolic profile of the cell-free supernatant of C. amycolatum to understand the nature and mechanism of the detected antibacterial action and provide further support for the probiotic potential of C. amycolatum vaginal isolates. [ABSTRACT FROM AUTHOR]

The levels of neurotrophic factors and the protein composition of somatic nerve membranes were studied during injury and survival of nerves in rats exposed to the action of clobetasol. It was shown that the drug administered intramuscularly induced a more pronounced increase in the level of neurotrophic growth factors and structural proteins responsible for recovery processes than the drug released from a hydrogel derived from microbial polysaccharides; it also stabilized the content of the total protein fraction in the damaged somatic nerves. Proteins of the injured neural conductor degraded less in animals receiving intramuscular injections of clobetasol, probably because the drug administered by injection had better availability than the drug administered from hydrogel composite (slow drug release). In addition, an increase in the amounts of DNA and some protein fractions indicated that clobetasol contributed the activation of genes associated with remyelination. We suppose that clobetasol can stimulate synthesis of neurotrophic growth factors, thereby triggering the phosphatidylinositol-3-kinase and mitogen-activated protein kinase signaling pathways that regulate the processes of cytoskeletal reorganization and axonal growth, as well as enhance the synthesis of structural and axonal proteins necessary to restore the functional activity of the injured nerve fibers. [ABSTRACT FROM AUTHOR]

Kindia tick virus (KITV) is a novel, segmented, unclassified flavi-like virus of the Flaviviridae family. This virus is associated with ixodes ticks and is potentially pathogenic to humans. The main goal of this work was to search for structural motifs of viral polypeptides and to model the 3D structure of the NS3 and NS5 viral proteins of the multicomponent flavi-like KITV. Materials and methods. Genome-wide sequences of KITV, Zika, dengue, Japanese encephalitis, West Nile, and yellow fever viruses from the GenBank database were used. Bioinformatics analysis was performed using the AlphaFold2, RCSB PDB, UCSF Chimera, NCBI BLAST, MOTIF Search, Protomenal, Unipro UGENE, and ESPript software package. Results. Analysis of the VP1–VP3 structural proteins of the KITV showed that they have no analogues with currently known viral proteins. Spatial models of two viral nonstructural NS3 and NS5 proteins of the KITV have been obtained. These models had a high level of topological similarity to the NS3 and NS5 proteins of the tick-borne encephalitis and dengue viruses. The domains of methyltransferase and RNA-dependent RNA-polymerase were found in the NS5 KITV and this was also represented by subdomains of fingers, palm, and thumb and motifs A–F. The helicase domain and its main structural motifs I, Ia, II, III, IV, IVa, V, and VI were identified in NS3 KITV. However, the serine protease domain typical for NS3 flaviviruses was not detected. The highly conserved motives 3–7 amino acids in length, typical for unsegmented flaviviruses, were detected in the NS3 and NS5 KITV. Also, eight amino acid substitutions were detected for KITV/2018/1 and KITV/2018/2, five of which are localized in alpha-helix and three in loops of nonstructural proteins. Conclusions. Nonstructural proteins of segmented flavi-like KITV have structural and functional similarities with unsegmented flaviviruses. This confirms their possible evolutionary and taxonomic relationships. [ABSTRACT FROM AUTHOR]

The requirements of ecological design for materials for various environmental objects are considered. The types of glasses and glass-ceramic materials for the design of environmental objects are presented. A wide range of surface-treatment methods for glasses and glass materials is shown, which determine their high decorative expressiveness along with operational properties. A classification of glass products is given according to the methods of forming and surface treatment, which determine the artistic, operational-technical, and physicochemical properties of glasses and glass materials. Particular attention is paid to stained-glass windows and the technology of their manufacture. [ABSTRACT FROM AUTHOR]

New complex salts [Pd(NH3)4]3[Ir(NO2)6]2x[Rh(NO2)6]2 – 2x (II–VI) were prepared, which are solid solutions based on double complex salts [Pd(NH3)4]3[Ir(NO2)6]2 (I) and [Pd(NH3)4]3[Ir(NO2)6]2. The obtained compounds were characterized by X-ray powder diffraction analysis, IR spectroscopy, and elemental analysis. The compounds crystallize in the cubic system (space group ). The thermal behavior of compounds I–VI in various gas atmospheres was investigated. The final products of thermolysis of [Pd(NH3)4]3[Ir(NO2)6]2x[Rh(NO2)6]2 – 2x in reducing (H2) and inert (He) atmospheres were trimetallic porous Pd–Ir–Rh nanoalloys. The final products of thermolysis in an oxidizing atmosphere were mixtures of metal oxide phases with an admixture of a metal phase. The structural and morphological properties of the formed nanoalloys were studied. The obtained solid solutions of double complex salts [Pd(NH3)4]3[Ir(NO2)6]2x[Rh(NO2)6]2 – 2x were used to synthesize alloy nanoparticles on the surface of a γ-Al2O3 oxide support. The catalytic activity and stability of the produced catalyst samples were tested in a model reaction of CO oxidation under forced thermal aging conditions. [ABSTRACT FROM AUTHOR]

The results of X-ray diffraction analysis of bacterial nanocellulose (BNC), synthesized by Komagataeibacter xylinus В-12429 and Komagataeibacter xylinus В-12431 producers in enzymatic hydrolyzates of miscanthus, oat hull, and synthetic nutrient medium, are presented. It is found by full-profile analysis that the dominant component in all BNC samples studied, independent of the producer and nutrient medium, is allomorph Іα, whose content varies from 96 to 100%. The following characteristics of the supramolecular structure of the samples have been determined: the degree of crystallinity, sizes of elementary fibrils and the shape of their cross section, and the coherence length of elementary fibrils along the fibril axis. [ABSTRACT FROM AUTHOR]

Corynebacterium amycolatum ICIS 99 was isolated from vaginal smears of healthy women and showed promising results in antimicrobial screenings. Here, we report the draft genome sequence of this strain and analyze its main features to assess its safety and useful properties. The genome is 2,532,503 bp long and contains 2186 CDSs with an average G + C content of 59.0%. Analyses of the ICIS 99 genome revealed the absence of true virulence factors. The genome contains genes involved in the synthesis of secondary metabolites and bacteriocins of the class sactipeptide. In the genome of ICIS 99, we identified a large number of genes responsible for adaptation and survival in the vaginal environment, including acid and oxidative stress resistance genes. The genomic information of ICIS 99 provides a basis for understanding the safety and useful properties of ICIS 99 and for considering it as a potential probiotic strain. The whole genome shotgun project has been deposited at DDBJ/ENA/GenBank under the accession number JAIUSU000000000. [ABSTRACT FROM AUTHOR]

New complex salts [Pd(NH3)4][Pd(NH3)3NO2][CrOx3]·H2O I, [Pd(NH3)4][Pd(NH3)3NO2][CoOx3]·H2O II, and a series of solid solutions [Pd(NH3)4][Pd(NH3)3NO2][CoOx3]x[RhOx3]1–x·H2O III–V are obtained and characterized. The compounds are studied by powder X-ray diffraction (XRD), elemental analysis, and IR spectroscopy. Crystal structures of complex salts I, II and K5[Pd(NH3)4][CrOx3]2NO3·6H2O VI are determined by single crystal XRD. Complex salts I and II crystallize in the monoclinic crystal system (space group of I and II is P21/n); complex salt VI crystallizes in the triclinic crystal system (space group of VI is ). The thermal behavior of compounds I–V is investigated in different gas atmospheres. Final products of the thermolysis of [Pd(NH3)4][Pd(NH3)3NO2][CoOx3]·H2O and [Pd(NH3)4][Pd(NH3)3NO2][CoOx3]x[RhOx3]1–x·H2O solid solutions in the reducing atmosphere are Pd0.7Co0.3, Pd0.7CoxRh0.3–x. The thermolysis of [Pd(NH3)4][Pd(NH3)3NO2][CrOx3]·H2O complex salt under the same conditions results in the formation of a two-phase mixture Pd1–yCry + Сr2O3 where y < 0.1. In the oxidizing atmosphere, the final products are mixtures of oxide phases of initial metals. [ABSTRACT FROM AUTHOR]

The global abundance and availability of oat hulls make them a promising feedstock to produce a unique type of cellulose, the bacterial one. This is the first study examining how a chemical pretreatment method of oat hulls influences the yield and properties of bacterial cellulose (BC) in extended cultivation. Here we employed our own pretreatment methods that use dilute HNO3 and NaOH solutions in one and two stages, a total of four pretreatment methods. Further technological stages were performed in the same manner: pulps were enzymatically hydrolyzed with commercial enzymes CelloLux-A and BrewZyme BGX, and biosynthesis of BC was run using the Medusomyces gisevii Sa-12 symbiotic culture. A two-stage (HNO3 + NaOH) pretreatment of oat hulls was found to afford a biologically good medium and increase the BC yield 1.8−3.2-fold compared to the other pretreatments used. A pretreatment method of oat hulls determined the BC yield and degree of polymerization. However, a pretreatment method had no impact on the highest crystallinity index and allomorph Iα content of all the BC samples, which is explained by Medusomyces gisevii Sa-12 used. The crystallinity index and allomorph Iα content, as measured by X-ray diffractometry, are proposed for use as BC quality assessment criteria. [ABSTRACT FROM AUTHOR]

New complex salts [Pd(NH3)4][Pd(NH3)3NO2][RhOx3]·H2O and Na3[RhOx3]·4H2O are prepared. The crystal structures of obtained compounds are determined by XRD. Complex salt [Pd(NH3)4] [Pd(NH3)3NO2][RhOx3]·H2O is studied by powder XRD, IR spectroscopy, and elemental analysis. The state of rhodium(III) in oxalate solutions is studied by NMR. Thermal behavior of [Pd(NH3)4][Pd(NH3)3NO2] [RhOx3]·H2O in various gas atmospheres shows that final thermolysis products in reducing and inert atmospheres are solid solutions Pd1–xRhx. [ABSTRACT FROM AUTHOR]

Possible mechanisms of the emergence of exciton and trion traps at room temperature and the dynamics of relaxation processes occurring in them are discussed, based on an analysis of the results from experiments on photon echoes in thin films of zinc oxide and doped silicon. The current–voltage characteristics recorded for such films with traps displaying the memristor effect are studied, and the influence traps exert on the parameters of such characteristics is established. [ABSTRACT FROM AUTHOR]

The study was performed for miscanthus introduced and grown in West Siberia. Transformation of miscanthus into bacterial nanocellulose was accomplished for the first time. The microbiological synthesis of bacterial nanocellulose using the Medusomyces gisevii Sa-12 symbiotic culture gave chemically pure bacterial nanocellulose with exceptionally high crystallinity index and content of Iα allomorph. [ABSTRACT FROM AUTHOR]

A mixed electrolytic deposit (ED) of PdCu (~20 at.% Cu) is synthesized from a solution of 1 mМ PdSO4 + 5 mМ CuSO4 + 0.5 M H2SO4 in the region of copper underpotential deposition (+400 mV vs. RHE). The incorporation of copper into the Pd deposit increases its true surface area (Strue) by a factor of ~20 and changes its hydrogen sorption characteristics. The ED PdCu demonstrates higher specific activity in FAOR as compared with individual Pd deposit (Еdep = 0.4 V). The specific solubility of Pd from ED PdCu is shown to be 2–3 times lower than the solubility of ED Pd; however, its total solubility from PdCu increases due to the strong increase in Strue. [ABSTRACT FROM AUTHOR]

The uniform broadening of spectral lines associated with the quantum transitions of room-temperature trionic states localized in traps on nanoscaled surface defects within the crystal structure of a three-layer Si(P)/Si(B)/ZnO film is investigated experimentally using the phonon echo approach. [ABSTRACT FROM AUTHOR]

Bacterial nanocellulose, which was produced by Medusomyces gisevii Sa-12 cultured in enzymatic hydrolysates of Miscanthus, was studied by X-ray diffraction. The characteristics of the supramolecular structure of the crystalline component of cellulose samples, such as the degree of crystallinity and the size and shape of elementary fibrils, were determined. The atomic structure was compared with the known structural models of cellulose, and the synthesized bacterial nanocellulose was shown to be cellulose Iα. The lengths and angles of the triclinic unit cell were determined. The composition of the culture medium made from enzymatic hydrolysates of Miscanthus was found to have an effect on the shape and size of elementary fibrils and have no effect on the degree of crystallinity and the fraction of cellulose allomorph Іα. The use of Medusomyces gisevii Sa-12 as the producing organism allows the preparation of bacterial nanocellulose with a high degree of crystallinity in the range of 86–93% containing cellulose allomorph Іα as the major component. [ABSTRACT FROM AUTHOR]

The conceptual possibility to synthesize bacterial cellulose nitrates with the use of commercial mixed acid was demonstrated. The initial bacterial cellulose was produced by the Medusomyces gisevii Sa-12 symbiotic culture in a synthetic nutrient broth in a Binder constant climate chamber. The resulting bacterial cellulose nitrate sample had 11.45% nitrogen content, 1900 cP viscosity, 15.8% solubility in ethanol—diethyl ether mixture, and 0.10% ash content. An extremely high sample viscosity (organogelation) in a ∼2% solution in acetone was observed. [ABSTRACT FROM AUTHOR]

Tick-borne encephalitis viruses (TBEVs) are usually divided into three major subtypes: European (TBEV-Eu), Siberian (TBEV-Sib) and Far Eastern (TBEV-FE). The TBEV-Eu strains have the longest genomes, and TBEV-FE strains have the smallest genomes. Changes in the variable region of the untranslated region (V3′ UTR) play a major role in determining the viral genome length. Analyses of the 3′ UTRs of the different subtypes of TBEV have revealed significant changes in the secondary structures of the V3′ UTR of TBEV. More complex secondary structures of the V3′ UTR regions are typical for TBEV-Eu. The Siberian strain Tomsk-PT122 was isolated from birds and has an unusual 3′ UTR. Several short fragment (24–26 nucleotides) insertions derived from the viral E (2) and NS4a (1) genes have been found in the V3′ UTR of Tomsk-PT122. Additionally, the length of the V3′ UTR increases from 21 to 37 nucleotides during passages of the C11-13 strain of TBEV-Sib into PEK, 293 and Neuro-2a cells. The elongation of the V3′ UTRs of Tomsk-PT122 and C11-13 is the first direct evidence of an intragenomic 3′ UTR modification (insertion) for TBEV. Thus, the obtained results suggest that changing the length of the V3′ UTR in the genome is typical for different TBEV subtypes and can play an essential role in effective TBEV replication in different host cells. [ABSTRACT FROM AUTHOR]

Abstract: This study evaluates how bacterial cellulose (BC) properties influence the efficiency of enzymatic hydrolysis. BC was produced by the Medusomyces gisevii Sa-12 symbiotic culture in an enzymatic hydrolyzate obtained from oat hulls and was characterized by Fourier-transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, and X-ray diffraction. The enzymatic hydrolysis was examined with dried BCs unwashed and washed of culture medium components and cell debris, as well as with wet BC washed of culture medium components, at initial solid loadings of 10 and 30 g/L. The enzymatic hydrolysis of the BC sample unwashed of culture medium components and cell debris exhibited a substrate conversion degree of 56.3-66.6%. The conversion degree of the BC samples washed of culture medium components and cell debris was 89.4-99.5%. The removal of culture medium components and cell debris increased the conversion degree by 1.5 times. The drying of wet BC was found to decrease the enzymatic hydrolysis rate but it did not affect the conversion degree: the maximum yield of reducing sugars of 99.5% was achieved in 56 h for dried BC and in 16 h for wet BC. The substrate's impurity content (growth medium components and cells) and moisture had the greatest effect on the performance of enzymatic hydrolysis of BC. The high BC crystallinity index of 90% was found to be not a determinant for the enzymatic hydrolysis efficiency.Graphical abstract: [ABSTRACT FROM AUTHOR]

Abstract: Bacterial nanocellulose (BNC) samples were produced by the symbiotic culture Мedusomyces gisevii Sa-12 in synthetic nutrient medium and enzymatic hydrolysates of chemically treated oat hulls and studied by X-ray diffraction. The structural characteristics of the crystalline component of BNC samples were determined. A comparison of the X-ray diffraction patterns recorded in reflection and transmission geometry shows that the samples have an anisotropic structure. All BNC samples are characterized by a high degree of crystallinity (from 86 to 93%) and are mainly composed of the low-symmetry metastable phase Iα (its fraction is 93.6-100%). The Мedusomyces gisevii Sa-12 culture was found to produce highly crystalline BNC, with the low-symmetry phase Iα prevailing, regardless of the composition of the nutrient medium. [ABSTRACT FROM AUTHOR]

The effect of culture conditions on the bacterial cellulose (BC) yield synthesized by symbiotic culture Medusomyces gisevii Sa-12 grown in synthetic nutrient medium was studied for the first time. The conditions providing the maximum yield of bacterial cellulose were evaluated: the initial glucose concentration in the culture medium was 20-25 g/L, the temperature was 24-27°C, the ratio of the nutrient medium to the air volume was 1 : 10, and the content of the black tea extracts comprised 1.6-4.8 g/L. A sample of chemically pure BC with the following characteristics was obtained under the selected culture conditions: moisture--99.0%, degree of polymerization--4800, average width of microfibrillar ribbons--30.6 nm, degree of crystallinity--86%, and the content of triclinic modification Ia--98%. [ABSTRACT FROM AUTHOR]

The C11-13 strain from the Siberian subtype of tick-borne encephalitis virus (TBEV) was isolated from human brain using pig embryo kidney (PEK), 293, and Neuro-2a cells. Analysis of the complete viral genome of the C11-13 variants during six passages in these cells revealed that the cell-adapted C11-13 variants had multiple amino acid substitutions as compared to TBEV from human brain. Seven out of eight amino acids substitutions in the high-replicating C11-13(PEK) variant mapped to non-structural proteins; 13 out of 14 substitutions in the well-replicating C11-13(293) variant, and all four substitutions in the low-replicating C11-13(Neuro-2a) variant were also localized in non-structural proteins, predominantly in the NS2a (2), NS3 (6) and NS5 (3) proteins. The substitutions NS2a (Asn → Asp), NS2a(Leu → Val) in the N-terminus of NS2a and NS3(His → Gln) in the helicase domain of NS3 were found in all selected variants. We postulate that multiple substitutions in the NS2a, NS3 and NS5 genes play a key role in adaptation of TBEV to different cells. [ABSTRACT FROM AUTHOR]

A method for determining the rms deviation of the heights of surface inhomogeneities based on an algorithm for calculating the spectral density of the one-dimensional correlation function over a wide range of spatial frequencies is developed and justified scientifically. The methodological errors of the algorithm are analyzed using experimental data from studies on a test stand under production conditions. [ABSTRACT FROM AUTHOR]

Mo/Al/Mo/Au metallization scheme as an ohmic contact to undoped AlGaN/GaN heterostructures was investigated. The optimal thicknesses of the metal layers were determined: Mo (10 nm)/Al (60 nm)/ Mo (50 nm)/Au (50 nm). The specific contact resistance of the fabricated ohmic contact is 4.7 × 10 Ohm cm (0.14 Ohm mm). The microstructure of the contact after annealing was investigated using scanning and transmission electron microscopy, X-ray diffractometry and energy-dispersive X-ray spectroscopy. It is shown that a noticeable alloying of metallization into semiconductor upon annealing does not occur, but strong mixing of metals takes place. X-ray diffraction analysis demonstrated the presence of interfacial compounds, namely, AlAu, AlMo, AlMo, AlMo, GaMo and GaAu. Investigations of the phase composition of films depending on the thickness ratio of the metallization layers have shown that the formation of AlAu phase has a negative effect on the contact surface morphology, and the formation of GaMo, AlMo phases likely plays the most important role in the ohmic contact formation, which was also confirmed by the method of energy-dispersive analysis. [ABSTRACT FROM AUTHOR]

Nanocrystalline СаО was synthesized using microwave technology. Vacuum and microwave drying was shown to yield nanosized calcium peroxide without organic dispersants. The size of synthesized particles was shown to have an effect on the thermal and CO chemosorption properties of calcium peroxide. [ABSTRACT FROM AUTHOR]

The efficiency of using a fluoropolymer dispersion in preparation of sheet lime chemisorbent was demonstrated. The surface morphology and the thermal and sorption properties of the СО absorbent were studied. The use of the fluoropolymer dispersion as a component of the sorption material allows elimination of alkali from the formulation, improvement of the sorption, moisture retention, and strength characteristics, and expansion of the application field of the material. [ABSTRACT FROM AUTHOR]

An absolute calibration algorithm has been implemented using the two-plane method. Optical surface profile recovery error is analyzed using mathematical modeling and experimental data. [ABSTRACT FROM AUTHOR]

The phase composition of the carbonatization products of nanocrystalline KO deposited on a glass fiber matrix has been studied using differential thermal analysis, X-ray diffractometry, and Raman spectroscopy. The results demonstrate that the possible carbonatization products of potassium superoxide and alkali nanocrystals are potassium carbonate (KCO), potassium bicarbonate (KHCO), and mixtures of these, depending on the reaction temperature. No new phases or chemical compounds with glass fiber were detected. [ABSTRACT FROM AUTHOR]

The Tunguska catastrophe occurred in the area of the East Siberian magnetic anomaly on June 30, 1908. The epicenter of the explosive destruction of the Tunguska cosmic body (TCB) was above the central neck of a paleovolcano (Mt. Stoikovich). According to the paleomagnetic data available, the bedrocks on the top of Mt. Stoikovich carry remanent magnetization, which is substantially higher than that in rocks from neighboring mountains. Analysis of the results of paleomagnetic measurements of rock samples collected in the vicinity of the Tunguska catastrophe epicenter showed that the destruction of the cosmic body was accompanied by the formation of multidirectional magnetic fields, which provide disturbances spreading over a distance of 25 km from the epicenter. The chaotic distribution pattern of magnetization vectors measured in the soil in the vicinity of the Tunguska catastrophe epicenter confirms the previously expressed assumption that destruction of the TCB was accompanied with multiple discharges. According to this, we can conclude that the matter of the Tunguska cosmic body was dispersed around the epicenter in a zone approximately 25 km in diameter. [ABSTRACT FROM AUTHOR]

Kinetics of carbon dioxide chemisorption and oxygen release under the natural convection kinetics at temperatures of 20 and 5°C by nanocrystalline KO deposited on a fiber-glass matrix was studied. The processes of oxygen release and carbon dioxide absorption are well described by the contracting-sphere equation. The reaction rate constants were calculated and the activation energy of the processes was estimated. To verify the suggested physical model, the concentrations of carbon dioxide and oxygen were calculated at other process parameters. It was demonstrated that nanocrystalline KO on a fiber-glass matrix can be effectively used to create local atmospheres in life-support systems. [ABSTRACT FROM AUTHOR]

A bicolor photodetector of ultraviolet radiation based on a ZnCdS/ZnMgS/GaP heterostructure is designed and analyzed. At low bias voltages, the detector has a narrowband response at a wavelength of 350 nm, which is determined by the composition of the ZnCdS quantum well. As the bias increases to 80-100 V, the maximum sensitivity of the detector is shifted to a wavelength of 450 nm with subsequent rapid decrease. In this case, the spectral sensitivity characteristic of the detector covers the region of the maximum pigmentation effect of solar radiation. [ABSTRACT FROM AUTHOR]

The concept of manufacturing valuable bacterial nanocellulose (BNC) from plant raw materials having a zero prime cost is substantiated. The process flowsheet involves the chemical transformation of the feedstock to obtain a pulp; enzymatic hydrolysis of the pulp to furnish a solution of reducing sugars, chiefly glucose; preparation of a nutrient broth based on the enzymatic hydrolysate; biosynthesis of nanocellulose microfibrils by the symbiotic Medusomyces gisevii Sa-12 culture; and purification of BNC. BNC has for the first time been synthesized from oat hulls and has a high degree of crystallinity of 88 ± 5% and is composed of 99% Iα-allomorph. [ABSTRACT FROM AUTHOR]

The kinetics of free moisture removal from a CaO paste under the conditions of convective drying and UHF field at atmospheric pressure were compared. Drying under the action of UHF radiation is characterized by the absence of the heat-up period. The use of the microwave radiation at atmospheric pressure decreases the drying time in production of anhydrous calcium peroxide by a factor of approximately 10 compared to convective drying. [ABSTRACT FROM AUTHOR]

Currently, the development of regenerative products based on highly porous glass fiber matrix, has proved to be one of the most promising trends in the field of creating regenerative products for air cleaning devices. The authors have developed a new technology for obtaining a regenerative product based on nanocrystals of potassium superoxide, which comprises the impregnation of porous fiberglass matrix with the alkaline solution of hydrogen peroxide followed by its further dehydration. The regenerative product based on the matrix has been shown to possess the better sorption characteristics, as compared to those of the serially manufactured ones. The developed regenerative product can be applied for lightweight design options of a self-rescuer, corresponding to the international standards. [ABSTRACT FROM AUTHOR]

The composition of solid products of vacuum decomposition of KO · 2HO ( I) on a glass fiber matrix was determined by Raman spectroscopy. The products were mainly mechanical mixtures of potassium superoxide KO ( II) with KOH · nHO ( III) and, in some cases, with KOH ( IV). The n value in III varies from sample to sample (most often, from 0.2 to 1). Component II is represented by the typical tetragonal phase (the ν(O-O) stretching maximum at 1146 ± 1 cm). The transformation of the tetragonal phase of II into cubic phase upon sample irradiation with a focused laser beam was studied. The phase transition was initiated by increasing the power of monochromatic radiation (λ = 514.5 nm). The formation of the cubic phase was indicated by a sharp increase in the width of the ν(O-O) stretching mode. Reaching the threshold power facilitates warming up of the sample in the focusing point to ∼120°C. In pure II, the phase transition is enantiotropic; when the laser radiation power drops to the initial minimal level, the tetragonal phase is formed again. When III or IV is present in the sample, this does not take place. Stabilization of the cubic phase of II is attributable to the chemical reaction with IV taking place at phase transition temperature to give a binary compound or a solid solution of the KO · KOH type ( V). The crystals of V correspond to the cubic system. [ABSTRACT FROM AUTHOR]

We have studied Raman spectra of single- and polycrystalline Pb 1 − xSn xTe (0 ≤ x ≤ 1) films on different substrates in relation to the intensity of the laser action. The composition of oxide phases on the surface of lead-tin telluride films has been described, and their modification as a result of photostimulated oxidation of the surface during measurements of spectra has been analyzed. We have shown that, for films with a small mole fraction of tin telluride ( x ≤ 0.26), irrespective of the crystalline state, predominant oxidation of tellurium with the formation of the compound TeO 2 takes place during the laser action. In films with a high content of tin, at a laser-action intensity higher than 1000 μW, tellurium dioxide TeO 2 on the surface is replaced with tin dioxide SnO 2. [ABSTRACT FROM AUTHOR]

An investigation of the Tunguska cosmic body's epicenter showed that both dried trees and those that survived the catastrophe are marked with characteristic deteriorations. For the trees that survived near the epicenter (the distance is <4 km), cracks of up to 7 m in length are found on their stems. All the vegetation near the explosion epicenter has traces of uniform scorch that covered the trees even on the land parts isolated by water. On the background of this uniform scorch, a notable feature is carbonization that touched the tree tops and the earth-directed ends of broken branches. All tops of both living and dried trees in the central zone are burned and dead. Carbonization of tops and branch ends was observed up to a distance of 10-15 km from the epicenter; i.e., charge processes took place over an area of more than 500 km in size. Carbonized branch ends have a characteristic 'bird's nail' shape, which has no analogs on the Earth. Similar deterioration is typical for the crater shape that obtains an anode during arc discharge combustion. It is supposed that the duration of these charge processes could be ≥1 min. [ABSTRACT FROM AUTHOR]