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The effect of different concentrations of fly ash aluminosilicate cenospheres on the structure and properties of elastomeric composites is studied. Composite materials based on ethylene–propylene–diene rubber (EPDM-40) with different mass fractions of fly ash (10, 20, 30%) are obtained using laboratory rollers. The microstructure of mixtures of EPDM and aluminosilicate cenospheres is studied by optical microscopy. It is shown that the concentration of the filler of more than 30 wt % increases the concentration of larger cenosphere agglomerates in the structure, which indicates interfacial separation in the mixtures, which is probably associated with the fact that mechanical mixing on mixing equipment does not make it possible to achieve uniform distribution of the filler throughout the elastomeric matrix. The appearance of new absorption bands in the region of 1400–800 cm–1 that correspond to the stretching vibrations of Si–O–Si present in aluminosilicate cenospheres is detected in the IR spectra. According to the thermogravimetry data of the compositions under study, the introduction of aluminosilicate cenospheres promotes a slight increase in the thermal stability of the composition under study with the concentration of cenospheres of more than 30%. The influence of the concentration of aluminosilicate cenospheres on the resistance of the composites to aggressive media is analyzed, and it is found that the introduction of a cenosphere filler in the amount of 10 to 30 wt % into mixtures based on EPDM can increase the oil and petrol resistance of the materials. [ABSTRACT FROM AUTHOR]

Modern trends focused on green technologies are driving the increasingly widespread use of biodegradable polymers in agriculture. The development of composite materials based on polylactide (PLA) is aimed at increasing the efficiency of using covering materials for growing plants in agriculture, as well as reducing the amount of polymeric wastes. In this work, mixtures of polylactide/polycaprolactone (PLA/PCL) and polylactide/natural rubber (PLA/NR) have been studied. It is established that, when about 10–15 wt % of PCL and NR are added to the PLA matrix, the structure changes and almost spherical domains are formed. In the course of studying the effect of UV radiation with a wavelength of 254 nm exerted on PLA/PCL and PLA/NR polymeric materials, it has been revealed that the presence of additives in the mixture already in an amount of 10 wt % promotes the inhibition of photolytic processes. [ABSTRACT FROM AUTHOR]

The effect of different concentrations of aluminosilicate fly ash cenospheres, as well as silver-coated aluminosilicate fly ash cenospheres, on the structure and thermal properties of polymeric composites has been studied. In the scope of this work, composites based on styrene–butadiene–styrene triblock copolymer and aluminosilicate cenospheres with different ratios between components in the mixture have been studied. By using optical microscopy, it has been shown that aluminosilicate cenospheres introduced into the polymeric matrix through a solution are evenly distributed throughout the entire volume of the film, with no formation of any aggregates or agglomerates. Thermal analysis has shown that cenospheres provide an increase in the thermal resistance of composites. At the same time, the increase in the aforementioned thermal parameters is correlated to a great extent with the amount of filler. By using infrared spectroscopy, it has been shown that the IR spectra of the composites exhibit new signals corresponding to the stretching vibrations of SiO2 and metal oxides. [ABSTRACT FROM AUTHOR]

Chemical analysis of samples of ovarian fluid (OF), a secondary product of breeding of the two common species of Acipenseridae family in Russian aquaculture, was carried out in order to assess its nutritional and possible medicinal value. It has been established that the dominant organic component of OF of both species is a water-soluble or water-dispersible protein easily absorbed by the digestive tract. Proteomic analysis of the samples has shown that the main component of the protein fraction of OF is a highly nutritious protein vitellogenin. Amino acid analysis has shown that 350 g of dried sturgeon OF or 245 g of dried sterlet OF satisfy the needs of an adult human in all essential amino acids per one day. Eighty-five grams of dried sturgeon OF or 55 g of dried sterlet OF covers the daily requirement of an adult for vitamins C, B1, B2, B3 (PP) and B6, a number of macroelements (Na, K, Ca, Mg) and microelements (Fe, Cu, Mn, Zn, Cr). Furthermore, Cu content is significantly higher in sturgeon OF, and Fe content is significantly higher in sterlet OF, which is partly confirmed by the relative content of Cu and Fe carrier proteins, ceruloplasmin and transferrin, respectively. In addition, a number of proteins of physiological significance for fish were identified. The possible medicinal value of OF consists, among other things, in significant content of various antioxidant proteins in OF of both species. The use of OF as a food supplement could improve the profitability of sturgeon breeding by producing an additional valuable product, and would also expand the range of natural dietary supplements on the market. [ABSTRACT FROM AUTHOR]

We analyzed frequency, duration and structure of songs of Thrush and Common nightingales in the recently established contact zone in the Ciscaucasia as well as in allopatric populations of the Kursk and Krasnodar regions. In the western Ciscaucasia, where the Common Nightingale bred in the 1970s, it was currently not found, being completely replaced by the Thrush Nightingale. At the same time, a large mixed population of these species with approximately equal species ratio was found in western Kalmykia and in the adjoining parts of the Stavropol region. The songs of the Common Nightingale and the Thrush Nightingale from allopatric populations differ significantly from each other in a set of variables as well as in the PCA analysis. By contrast, in the contact zone in the Ciscaucasia, a distinct mutual convergence of the songs of these species was found. We assume that there are two independent mechanisms for the exchange of songs between different species of nightingales. One of the mechanisms is the obvious borrowing by the Thrush nightingale of the integral song types of a Common nightingale through vocal learning. Another mechanism may be inherited changes in song patterns that have occurred due to hybridization. [ABSTRACT FROM AUTHOR]

The article analyzes the factors involved in making polyoxadiazole fiber-forming systems through spinneret capillaries under dry-wet method conditions. The drawbacks of the wet polyoxadiazole fiber forming method were identified. A method of two-stage extrusion of solutions of polyoxadiazole fiber-forming systems, the first of which is carried out through spinneret holes into a gaseous medium and the second, in a precipitating dilute sulfuric acid bath, is proposed. A mathematical interpretation of the technological factors of polymer solution flow through spinneret capillaries, including the rate of solution flow through capillaries with different diameters and spinneret drafting, is offered. [ABSTRACT FROM AUTHOR]

The results of theoretical and experimental studies of impact ionization processes and charge carrier heating in multi-valley AIIIBV semiconductors at high electric field are presented and their relationship with the features of the band structure is discussed. A role of subsidiary L- and X-valleys, complex structure of the valence band and orientation dependence of the ionization coefficients are taken into account. A new approach to the choice of semiconductor materials with a large ratio of the ionization coefficients of holes and electrons to create the noiseless avalanche photodiodes due to monopolarity of hot charge carrier multiplication is proposed. [ABSTRACT FROM AUTHOR]

A general geographic characteristic of the Vistula basin and mouth area is given; brief data on the modern hydrological regime of the river mouth are presented. The history of floods in the Vistula delta and their studies is considered in detail, as well as delta evolution and the dynamics of its hydrographic network. [ABSTRACT FROM AUTHOR]

A stable diradical 2-{N-[(3s,5s,7s)-adamantyl-1]-N-oxylamino}-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-3-oxide-1-oxyl—a heteroatomic analogue of trimethylenemethane—has been synthesized by reacting lithiated 4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-3-oxide-1-oxyl with 1-nitroso-adamantane, followed by oxidation of the intermediate hydroxylamine. According to X-ray diffraction data, the dihedral angle between the planes of paramagnetic moieties in the paramagnet is close to 60°. Magnetochemical measurements have shown that the energy gap between the triplet and singlet states (2J/kB; H = –2JS1/2S1/2) in the diradical is 880 K. The EPR spectrum of the diradical was simulated using the parameters: S = 1, gxx = 2.007, gyy = 2.005, gzz = 2.006, D = 825 MHz, E = 60 MHz. According to the data of cyclic voltammetry in the anodic region, the diradical undergoes electrochemical oxidation at potentials of 0.79, 1.63, 1.89, and 2.25 V, the first process being chemically and electrochemically reversible. In the cathodic region, the diradical is reduced quasi-reversibly at –1.18 and irreversibly at –2.59 V. [ABSTRACT FROM AUTHOR]

Abstract—Boris Izrailevich Khudy-Khodorov was a biophysicist-electrophysiologist and neurophysiologist, professor, author of a number of monographs and dozens of articles in leading scientific journals, and the founder of a scientific school, who educated a Pleiad of neurophysiologists and neurobiologists who head laboratories or work in research, both in domestic and in foreign scientific institutes and universities. Boris Khodorov passed away in 2014. This year, students and former colleagues of Boris Khodorov celebrated his 100th birthday, and in honor of this event, a conference was organized at the Institute of General Pathology and Pathophysiology, where he worked until his final days. This work was written by disciples of Boris Khodorov. It briefly outlines his biography, and also provides an overview of the scientific areas in which Boris Khodorov was engaged throughout his productive scientific activity: from the study of reflexes, to the analysis of the mechanisms of action of anesthetics and functioning of channels, and ending with studies on the mechanisms of regulation of intracellular calcium levels during toxic glutamate exposure. [ABSTRACT FROM AUTHOR]

The AURA experiment is part of a series of astrophysical radio-ice experiments, one of the goals of which is to search for cosmogenic neutrinos. This paper presents the capabilities of AURA for detecting neutrinos with energies above 1017 eV, presents the results of calculating the effective volume of the detector and analyzing data for 2009–2011, and presents preliminary estimates of the upper limit of the neutrino diffusion flux established by the AURA experiment. [ABSTRACT FROM AUTHOR]

This paper examines key features of the preparation of high-purity Ga from electronic and electrical engineering industry waste. The decrease in the melting point of impurity-containing Ga is assessed thermodynamically in the ideal solution approximation. It is proposed that the purity of gallium in the final crystallization purification step can be monitored via precision measurement of the temperature of the melt with a pyrometer. [ABSTRACT FROM AUTHOR]

River deltas which are among the most variable and vulnerable geographic objects may be considered as effective indicators of large-scale global and regional, natural and anthropogenic changes of environment. The up-to-date state of deltas of the main rivers in Russia and all over the world are described in the Register which is presented in this paper. The Register includes geographic characteristics of deltas (including their hydrologic-ecologic state), hydrographic, morphometric and hydrologic characteristics of the deltas. [ABSTRACT FROM AUTHOR]

The article examines delta formation processes and suggests a new approach to their study. In the paper, delta formation is divided into its active and passive component. The article assesses natural and anthropogenic external factors that impact delta formation, as well as modern trends in changing of the world's deltas. [ABSTRACT FROM AUTHOR]

The current state, the hydrological problems of river mouths, and the history of their studies as specific geographic objects are discussed, and the main lines and schools of researches in river mouths are characterized. Special attention is paid to the theoretical results of river mouth studies: water flow dynamics and water regime, river water and seawater mixing, and morphological processes. Finally, the urgent problems in river mouth hydrology are discussed. [ABSTRACT FROM AUTHOR]

The electronic structure has been calculated for new CoGeN2, CrGeN2, MnSiN2, and MnGeN2 crystals with a chalcopyrite structure in the antiferromagnetic (AFM) and ferromagnetic (FM) phases. It has been found that the AFM state is energetically favorable for all four materials. For the first time, the electronic properties of CoGeN2 and CrGeN2 have been studied using two exchange-correlation functionals, namely, GGA-PBE and PBE0. The second approach differs from the first one in that it includes the correction for the Coulomb self-interaction error (SIE) for strongly correlated 3d electrons. For example, without applying this correction, the bandgap in CoGeN2, MnSiN2, and MnGeN2 in the AFM phase is 0.11, 1.45, and 0.91 eV, and with inclusion of the SIE correction, it is 1.46, 3.47, and 1.37 eV, respectively. Without the SIE correction, CoGeN2 has metal properties for both spin orientations, and when the SIE correction is applied, it is a direct-gap semiconductor with a bandgap of 1.38 eV for spin up and 1.77 eV for spin down. The crystals under consideration are promising materials for magnetoelectronic applications. [ABSTRACT FROM AUTHOR]

The article describes a multiparametric approach to the assessment of cutaneous microcirculation in dermatological patients (using the example of psoriasis patients). The multiparametric diagnostic approach consisted of three stages of successive measurements performed according to the methodology of laser speckle contrast imaging (LSCI), laser Doppler flowmetry (LDF), and videocapillaroscopy (VCS). Experimental studies on hemodynamic parameters were conducted in psoriatic patients with a course of conservative treatment. A combined application of optical noninvasive diagnostic methods allowed physicians to record changes taking place in the microcirculatory bed during treatment. It has been found that microcirculatory disorders observed before the start of treatment in the field of psoriatic plaques (an increase in the density of the capillary network, an increase in the indicator of microcirculation, nutritive blood flow and the amplitudes of myogenic and cardiac oscillations) were normalized due to the applied treatment, on which the assessment of its efficacy may be based. The suggested approach may be used for diagnosing microcirculatory disorders emerging in psoriasis in its preclinical stage, as well as for developing and testing new pharmacological means for its treatment. [ABSTRACT FROM AUTHOR]

The animal breeding properties may be improved through the integrated use of the common breeding methods and the modern technologies for DNA-based molecular genetic markers associated with the economically important traits. Livestock breeding industry requirements for effective DNA marking the animal production performance traits tend to increase each year, which ensures the real relevance of research in this sphere. The objective of the surveys is to evaluate the Yorkshire and Landrace pigs with regard to the lineage assignment with the PRKAG3, MC4R, and MYOD1 marker-gene panel. The surveys were carried out with the populations of Yorkshire and Landrace animals within the lineages in Minsk oblast in 2019–2020. At the first stage of surveys, the pedigree young stock was evaluated based on the production performance parameters. At the second stage, fattening and meat-quality parameters were assessed. In order to study polymorphisms in the PRKAG3, MC4R, and MYOD1 genes, the ear tissue biosamples taken from the analyzed animals were used. DNA isolation was performed with the Nucleo-Sorb reagents (Praimtech, Belarus). The analysis of gene polymorphisms was performed with the PCR-RFLP method. In the analyzed animals, the frequencies of occurrence of the preference alleles at the gene markers for fattening and meat-quality performance traits were recorded. They comprised 0.171–0.288, 0.243–0.315, and 0.064–0.477 for PRKAG3I, MC4RA, and MYOD1C, respectively. With respect to the Yorkshire breed, the lineage of Dobryi 2313 was considered best among the analyzed lineages. Its representatives were more efficient in the fattening and meat-quality performance than the animals of the other lineages by 1.2–19.3%. With respect to the Landrace breed, the lineage of Dantes 5440 was considered most efficient, since its values for production performance were 0.3–9.8% higher than the breed averages. The use of the tested development in the pig breeding industry can provide the opportunity to accelerate the management of selective-breeding practice in order to improve the fattening and meat-quality performance in the breeding herds of the analyzed animals built at the lineage level. [ABSTRACT FROM AUTHOR]

Regularities of spasmodic delta formation, a rare type of the process, accompanied by breakthroughs and radical transformations of delta hydrographic network, are discussed. The physical prerequisites of this type of delta development are identified; a new scheme of process development and its new division into stages are proposed. Examples are given. [ABSTRACT FROM AUTHOR]

A high prevalence of immunodeficiency states has been a global challenge in recent decades. There are numerous factors that lead to immune deficiency, including the removal of the spleen (splenectomy) associated with the development of postsplenectomy syndrome. This syndrome is characterized by manifestations of secondary immunodeficiency and accidental involution of the thymus. This can negatively affect the reactivity of cells of the offspring's immune system, thus increasing the risk of tumor growth. The aim of this research was to study the reactivity of populations of CD68+ cells, CD45RO+ cells, and cells containing catecholamines in the spleen of the offspring of splenectomized female rats at the age of 3 and 6 months in response to tumor development in the colon. The features of changes in CD68+- and CD45RO+ cell number and biogenic catecholamine levels were studied using the fluorescence and immune histochemiсal methods. It was shown that the reactivity of cells of the macrophage–monocytic system and spleen T-lymphocytes to tumor development in the colon was less pronounced in the offspring of splenectomized rats than in the offspring of intact rats against a background of a low level of catecholamines in the fluorescent structures of the white and red pulps of the spleen. Thus, the course of pregnancy in a state of immunodeficiency caused by splenectomy leads to a decrease in the catecholamine level in spleen of the offspring against a background of carcinogenesis, accompanied by a low reactivity of macrophages and T-lymphocytes. [ABSTRACT FROM AUTHOR]

The causes and features of storm surges formation in the Venetian Lagoon are discussed. The experience of sea level observations in Venice and the history of floods caused by storm surges, in particular, acqua alta of 1966 and 2019, are described. The recurrence of storm surges was found to increase in the recent 60 years. The hydroengineering measures aimed to protect Venice against floods are considered. [ABSTRACT FROM AUTHOR]

Changes in the adhesive characteristics of polyethylene, polypropylene, polystyrene, polyethylene terephthalate, polyvinyl chloride, and polycarbonate films and powders as a result of irradiation with 3-MeV electrons in air have been studied. Radiolytic oxidation forms polar groups on the surface of the plastics and thus increases the surface hydrophilicity. At a dose of 100 kGy, the contact angle decreases by 6° for polyvinyl chloride and by 20° for polyethylene. The radiation-induced improvement in adhesion is mainly due to an increase in the polar component of surface energy. For polypropylene, the adhesion increases by a factor of 2.5. The use of irradiated polypropylene powder in epoxy compositions improves their stress–strain characteristics. [ABSTRACT FROM AUTHOR]

The tobacco mosaic virus was used as a stabilizer and reductant for silver nanoparticles. The conditions for obtaining a narrow distribution of silver nanoparticles were determined for the first time by varying the concentration of the initial silver nitrate solution. This result was confirmed by a wide range of mutually complementary methods such as spectrophotometry, dynamic light scattering, velocity sedimentation, and atomic force microscopy. The characteristics of the initial sample of the tobacco mosaic virus and silver nanoparticles stabilized by it both in solution and on a substrate were determined. [ABSTRACT FROM AUTHOR]

The short lifetimes of multibranch delta systems are proved based on the theory of dynamic stability of delta branches and causes of its violation. Typical cases of such brevity and natural causes of the decay of some branches and the activation of others are considered. Examples of such processes in different deltas are given. [ABSTRACT FROM AUTHOR]

The processes of radiative recombination and impact ionization in light-emitting structures based on bulk semiconductors, heterostructures with high potential barriers, nanostructures with deep quantum wells, and nanocrystals with quantum dots are reviewed. It is shown that enhancement of the quantum efficiency and luminescence optical power in all the investigated structures is caused by a common physical mechanism, specifically, the creation of additional electron–hole pairs during impact ionization by hot carriers heated at the high band offset at the heterointerface under current pumping or by the multiplication of carriers in nanocrystals upon multiexciton generation under illumination by high-energy photons. [ABSTRACT FROM AUTHOR]

Hydrodynamic methods and light scattering were used in the studies of solutions of a surface active monomer 11-acryloyloxyundecyltrimethylammonium bromide (AUTA-Br) and its polymers in 0.05 M NaCl. Aqueous solutions of AUTA-Br monomer in the concentration range of 4 to 16 CMC contain individual molecules and near-spherical AUTA-Br aggregates. The pAUTA-Br polymers possess rather high equilibrium rigidity (11.8 nm). This high value of equilibrium rigidity found for pAUTA-Br macromolecules is apparently caused by two factors: the presence of a bulky side substituent in each AUTA-Br monomer unit and incomplete suppression of electrostatic interactions between neighboring monomer units in the backbone. [ABSTRACT FROM AUTHOR]

The study describes antifouling coatings with low surface energy designed to prevent marine biological fouling. A non-biocidal enamel has been synthesized from film-forming epoxy made on the basis of aromatically conjugated hydroxyphenylene and modified with pre-fluoropolyester fluids. The results of laboratory and field tests are presented; a pilot industrial production of enamel is organized. [ABSTRACT FROM AUTHOR]

Alcohol is the third most important risk factor for disease in Russia and throughout the world. WHO data indicate that alcohol abuse kills 2.5 million people a year around the world, which is the population of a large city; of these, 600–700,000 occur in Russia. Despite the development of science and medicine, the mechanisms underlying the development of alcohol dependence remain unclear. An understanding of these mechanisms will help create novel approaches to the treatment of alcohol dependence. It is now known that the mesolimbic dopamine system plays a key role in forming addictive disorders, particularly alcohol dependence. Fast scanning cyclic voltammetry (FSCV) is a widely used method for studying dopamine. An advantage of this method is its high time and spatial resolution, making FSCV a powerful method for detecting changes in monoamine neurotransmitter concentrations in vivo. Our studies using FSCV in freely moving animals demonstrated that electrical stimulation of the ventral tegmental area (VTA) leads to detection of dopamine release in the nucleus accumbens (NAcc). We showed that acute ethanol injections (0.5 g/kg) lead to significant decreases in dopamine release in the NAcc induced by electrical stimulation of the VTA in freely moving rats. Use of the selective dopamine D2 autoreceptor antagonist raclopride significantly increased the measured signal, indicating that the incoming signal measured in the NAcc is dopaminergic rather than noradrenergic. [ABSTRACT FROM AUTHOR]

The determination of the carnosine level in fish muscle tissues is helpful for the purposes of general biology and comparative muscle physiology of various fish species; it may be also useful for estimation of the nutritional value of fish products. The mass-spectrometric method of the determination of carnosine in muscle tissues has been improved and tested in this work. The carnosine levels in the muscles of the Russian sturgeon, Siberian sturgeon, sterlet, hybrid of sterlet and kaluga, hybrid of Siberian sturgeon and kaluga have been determined for the first time with this method. The starlet-and-kaluga hybrid, regardless of sex, contains 3.33 times more carnosine than the sterlet (p < 0.01). The female hybrid of Siberian sturgeon and kaluga contains 1.50 times less carnosine than the female Siberian sturgeon (p < 0.1). Since carnosine consumption is important for carnosine biosynthesis in human muscles, the hybridization of sterlet with kaluga is more efficient in terms of nutrition value than pure sterlet breeding, and the hybridization of Siberian sturgeon with kaluga is less effective than sturgeon breeding. [ABSTRACT FROM AUTHOR]

The relationships between various hydrological and morphometric characteristics of branch channels in the backwater zone are analyzed in the case of the Chilia channel system in the large nontidal Danube delta. This zone shows a stabilizing effect of the weakly varying Black Sea level. Criteria for determining the boundaries of this zone are discussed. [ABSTRACT FROM AUTHOR]

We report the electrochemical deposition of Sn–Ni and In–Ni alloys containing 20 and 45 wt % of the lower melting point component. The percentage of nickel in the deposited alloys has been determined by gravimetric analysis. We have studied the thermal behavior of the deposited materials in heating–cooling cycles in the temperature ranges 50–250, 50–300, and 50–400°C. The results of this study can be useful in high-density mounting using Pb-free solder materials with a preset soldering temperature. [ABSTRACT FROM AUTHOR]

A comparative study of the allele pool and the genetic structure of two Russian and one Belarusian populations of the wisent Bison bonasus against the representatives of the species of Bison bison and the genus Bos taurus was carried out. Russian populations were represented by samples of the Oka State Natural Biosphere Reserve (n = 42) and the Prioksko-Terrasny Nature Biosphere Reserve (n = 69), the Belarusian population was represented by samples of the Reserve "Belovezhskaya Pushcha" (n = 42), bison samples (n = 8) and cattle (n = 55) were used as an outgroup. The analysis of the mtDNA D-loop 630 bp fragment polymorphism for the presence of bison and cattle haplotypes, was performed. It was shown that there was a single haplotype for all wisent (Bison bonasus) which was different from the sequences of bison (Bison bison) and cattle. The analysis of population genetic parameters, calculated using 11 microsatellite markers, showed reduced diversity in wisent (Bison bonasus) groups compared to bison (Bison bison) and cattle. The largest number of monomorphic loci as well as the absence of private alleles were found in the group of Belarusian wisent. The analysis of the DJost pairwise genetic distances allowed us to establish clear genetic differentiation of the wisent from the outgroups. This fact was also confirmed by PCA analysis, carried out in the context of population identity and the analysis of population structure which demonstrated some proximity of bison (Bison bison) to wisent (Bison bonasus), which is due to their belonging to the same genus. The data obtained from this study showed differentiation between wisent (Bison bonasus) from bison (Bison bison) and cattle. It can be used in assessing the population genetic parameters of wisent, identifying and eliminating hybrid individuals. It also can be used in developing strategies and measures for the preservation and improvement of the wisent genetic resources. [ABSTRACT FROM AUTHOR]

A method for producing a material for filtering air mixtures consisting of nonwoven material combined with a form-stable mesh is proposed. The nonwoven fabric is made from Arselon fibres. [ABSTRACT FROM AUTHOR]

The article presents the results from comprehensive investigation of the physicomechanical and physicochemical properties of polyoxadiazole fibers by thermogravimetric, differential scanning colorimetric, and thermomechanical methods. It was established that the fiber retains its strength up to 85% after exposure in air for 300 hours at 250 °C. [ABSTRACT FROM AUTHOR]

The authors propose a textile filtering material based on a fabric on the receiving side, which is connected with a nonwoven fabric using a needle-punching machine followed by calendering. The technical characteristics of the proposed material, including its thickness, surface density, thread linear density, and raw material composition are determined. The physical, mechanical, and operational characteristics of the textile material for filtration of hot process gases and industrial air are specified. [ABSTRACT FROM AUTHOR]

The types and specific features of the internal and external water exchange in nontidal deltas are discussed. The results of hydraulic calculation of water exchange in the branch–bypass–delta lake are given. The conclusions are confirmed by data of observations in several large nontidal and microtidal deltas. [ABSTRACT FROM AUTHOR]

At present, 75–80% of the current operating costs of conventional transport are expended for fuel. According to the International Maritime Organization, the world fleet burns 300 million tons of fuel annually, releasing into the atmosphere 960 million tons of СО2 and 9 million tons of SO2. As a result of fouling, the speed of ships may decrease by 50%. By 2020, without new technologies that reduce fuel consumption, air emissions can grow 40%, taking into account constantly increasing volumes of traffic. Therefore, defense methods against marine overgrowth are an urgent topic, and many leading firms are developing antifouling solutions. The paper considers the main means of protection against fouling with the help of polymer coatings, namely, contact active coatings, nonleaching coatings, self-polishing coatings, and non-biocidal coatings. The mechanism of using polymer coatings, as well as their advantages and disadvantages, is described. [ABSTRACT FROM AUTHOR]

Ground (expedition) and remote (space-based) methods have been used to carry out detail studies of variations of Danube delta coastline (DC). The displacements of the DC (the progradation or retreat) have been shown to be an effective indicator of the process of delta formation as a whole: the dynamics of the channel network and the redistribution of water and sediment flow between branches, as well as the effect on the delta of external factors (river water and sediment runoff, wind, sea waves, and sea level rise and drop). The contributions of different factors to sand sediment balance have been assessed in seven genetically homogeneous areas to find the causes and features of variations of Danube DC. The areas of DC progradation and retreat have been identified. The comparison of the results of studying the dynamics of Danube DC with the data on changes in the structure and regime of other large deltas can be used to reveal the causes and trends in the modern processes in river deltas. [ABSTRACT FROM AUTHOR]

The development of functional nano-crystalline cellulose hybrid suspensions has been in the focus of many areas of industry and academia for the past decades. The attention is elucidated from a unique biocompatible, mechanical, solution etc. properties of cellulose based systems. Fabrication of functional cellulose hybrids with customized features requires detailed knowledge of their final properties as well as understanding the structure–property relationships between the initial ingredients. The reported study investigates the formation and corresponding fundamental solution and molecular characteristics of highly disperse nano-crystalline cellulose hybrids with aluminum oxide nanoparticles. The characterization of the final complexes and its primary components was performed mainly in solution, using basic complementary hydrodynamic approaches, substantially—sedimentation velocity analysis in the analytical ultracentrifuge and related techniques. The analysis of the solution behavior resolved information about the hydrodynamic size, molar mass, shape, asymmetry and composition of the complexes. Additionally morphology of the cellulose hybrids was investigated by scanning force microscopy. To this end we demonstrate complete structural examination of highly disperse colloidal suspensions of crystal nano-cellulose modified by aluminum nanoparticles using classical solution characterization techniques. [ABSTRACT FROM AUTHOR]

It has been shown that a cationic copolymer based on poly(aminoethyl methacrylate) is capable of stabilizing silver nanoparticle dispersions in aqueous media. Nanoparticles have been prepared via chemical reduction of AgNO3 in an aqueous solution with sodium borohydride in the presence of a cationic random terpolymer—poly(2-aminoethyl methacrylate-co-N-methyl-2-aminoethyl methacrylate-co-N,N-dimethyl-2-aminoethyl methacrylate). Spectrophotometry has been employed to show that silver dispersions formed in the presence of the copolymer are stable for a long time (more than half a year). Using dynamic light scattering and scanning electron microscopy, consistent information has been obtained on the sizes and size distribution of the stabilized nanoparticles. [ABSTRACT FROM AUTHOR]

Reducing and stabilizing abilities of three poly(ethylene glycol) (PEG) samples modified with primary amino groups in one or two terminal positions of the polymer chains, as well as with dendrons based on L-aspartic acid in both terminal positions of the polymer chains, have been studied. Stable dispersions of silver nanoparticles have been formed at room temperature in aqueous solutions of AgNO3 in the presence of the modified PEGs without additional reducing agents. Spectrophotometric examinations have shown that an increase in the number of amino groups per polymer molecule results in accelerating the formation of nanoparticles and improving the stabilizing ability of the modified PEGs. Molecular hydrodynamic methods (analytical centrifugation and dynamic light scattering) have been used to determine the absolute values of the molecular mass of silver nanoparticles stabilized with dendronized PEGs and the hydrodynamic sizes of the particles. Molecular hydrodynamics and electron microscopy have yielded interconsistent estimates of silver nanoparticle sizes. [ABSTRACT FROM AUTHOR]

This overview is devoted to the discovery, development of the technology, and investigation of III–V semiconductors performed at the Ioffe Institute, where the first steps in fabricating III–V semiconductors were taken in 1950 and investigations into their fundamental properties were begun under the leadership of two outstanding scientists—Nina Aleksandrovna Goryunova and Dmitry Nikolayevich Nasledov. Further development of these investigations is reflected in the works of followers and pupils of D.N. Nasledov, who have worked and continue to work at subsidiaries of the Ioffe Institute. The contribution of these investigations to studying heterostructures based on III–V compounds as well as to the development of semiconductor devices for electronics, optoelectronics, and photonics is considered. [ABSTRACT FROM AUTHOR]

The electroluminescent characteristics of a type-II n-GaSb/n-InAs/p-GaSb heterostructure with a single deep quantum well grown by metalorganic vapor-phase epitaxy are investigated. The energy-band diagram of the structure and the positions of the electron and heavy-hole energy levels are calculated. The analysis of the current–voltage characteristics demonstrates that the dark current in the structure under study flows via the tunneling mechanism. Intense electroluminescence characterized by a weak temperature dependence was observed in the spectral range of 3–4 μm at T = 77 and 300 K. The main electroluminescence band (hν = 0.40 eV at 77 K) corresponds to direct radiative transitions between electrons from level E1 in the InAs quantum well and heavy holes from the continuum at the n-GaSb/n-InAs heterointerface. A low-intensity electroluminescence band at hν = 0.27 eV (T = 77 K) originates from indirect (tunneling) transitions from the first electron level in the quantum well to the second level of heavy holes localized in the valence-band "notch" at the n-InAs/p-GaSb heterointerface. [ABSTRACT FROM AUTHOR]

We report on the unusually large blue shift of electroluminescence spectrum with increase of the drive current at 77 K in a double-barrier nanoheterostructure with a deep AlSb/InAs0.83Sb0.17/AlSb quantum well grown by MOVPE on n-GaSb:Te substrate. The rise of drive current from 20 to 220 mA led to shift of the electroluminescence spectrum maximum towards higher photon energies by 100 meV. It was shown that this effect is due to indirect (tunneling) radiative transitions between electrons in InAsSb quantum well and heavy holes localized near AlSb/p-GaSb heterointerface. Energy of radiative transition was linearly dependent on applied voltage. In the drive current range of 50–220 mA electroluminescence blue shift was accompanied by the spectrum narrowing by 40 meV and noticeable change of the spectrum shape. With rise in drive current superlinear increase of electroluminescence intensity caused by the nonlinear dependence of tunneling radiative recombination rate on transition energy was observed at 300 and 77 K. [ABSTRACT FROM AUTHOR]

A comprehensive investigation of the properties of poly(paraphenylene-1,3,4-oxadiazole) fibers showed that items based on them were dimensionally stable during operation up to 400°C and retained high strength indicators after prolonged action of soil microorganisms. The fiber tensile strength remained at 78-80% after exposure to light for 2,000 h; at 93-95%, if a stabilizer was added. The investigation results predict high retention of mechanical properties of cloth based on Arselon® fiber during operation of items made from them under Russian Northwest and similar conditions. [ABSTRACT FROM AUTHOR]

Colorectal tumors were studied 5 months after carcinogen injection to outbred albino rats with secondary immunodeficiency by common histological and immunobiochemical methods with the use of monoclonal and polyclonal antibodies to Ki-67, Bcl-2, p53, and VEGF. Injection of carcinogen to intact animals led to the formation of adenocarcinomas with high and moderate cell differentiation in the colon, while injection of carcinogen to animals with immunodeficiency was associated with a 1.5-fold higher incidence of GRADE 2 and GRADE 3 adenocarcinomas with more aggressive morphological phenotype and appearance of distant metastases. [ABSTRACT FROM AUTHOR]

Significant photocurrent/photoconductivity amplification is observed at low reverse biases in a type-II n-GaSb/InAs/p-GaSb heterostructure with a single quantum well (QW), grown by metal-organic vapor phase epitaxy. A sharp increase in the photocurrent by more than two orders of magnitude occurs under exposure of the heterostructure to monochromatic light with a wavelength of 1.2-1.6 μm (at 77 K) and the application of a reverse bias in the range 5-200 mV. The optical gain depends on the applied voltage and increases to 2.5 × 102 at a reverse bias of 800 mV. Theoretical analysis demonstrated that the main role in the phenomenon is played by the screening of the external electric field by electrons accumulated in the deep InAs QW and by the mechanism of the tunneling transport of carriers with a small effective mass. It is shown that the effect under study is common to both isotype and anisotype type-II heterojunctions, including structures with QWs and superlattices. [ABSTRACT FROM AUTHOR]

The paper considers the major geographic features of the modern Huang He delta, which ranks among the most rapidly varying in the world. The structure of the hydrographic network and the combination of the natural and anthropogenic geosystems of the delta are characterized. The major external riverine and marine, as well as local anthropogenic factors that have affected the development of the Huang He delta in the recent half century are identified. The regularities of the jump-like development of the Huang He delta in the XIX-early XXI centuries are considered. Special attention is paid to the development of the delta after the artificial redistribution of flow in its boundaries in 1996. Satellite images and methods of their interpretation improved by the authors were used. The trends in Huang He delta development are shown to have changed since the last quarter of the XX century under the effect of an abrupt decrease in river sediment load and the growing impact of marine factors. The active progradation of the delta into the sea slowed down significantly, accompanied by erosion and retreat in many segments of its coastline. Huang He delta was used to establish the conditions of changes in the development trends of other deltas under the effect of changes in the climate and economic activity. [ABSTRACT FROM AUTHOR]

n-GaSb/n-InAs/p-GaSb heterostructure with a single InAs QW was grown for the first time by MOVPE. Photocurrent spectra were obtained at reverse bias in the range from 0 to 0.8 V. It was shown that the photocurrent increases nonlinearly. The maximum of differential photoconductivity is archived at low applied voltage up to 0.2 V. This effect was explained by electrostatic screening of electrons localized in QW. [ABSTRACT FROM AUTHOR]

The hydrographic, climate, hydrological, and landscape features of the Huanghe R. Basin are considered. Water runoff and suspended sediment load in the Huanghe R. are shown to have dropped significantly in 1950-2009 under the effect of regional climate changes and economic activity in the basin. Water balance method and the concept of flow transport competency were used to assess the contribution of natural and anthropogenic factors (decline in precipitation, water withdrawal for economic needs, and the effect of reservoirs) to the decrease in river water runoff and suspended sediment load. [ABSTRACT FROM AUTHOR]