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Li)ZnFeO ferrites ( x = 0.2; 0.4) were produced by thermal and radiation-thermal (RT) synthesis from LiCO-FeO-ZnO powder mixtures and then studied using x-ray diffraction (XRD) and saturation magnetization analysis. The RT synthesis was carried out by 2.4 MeV electron beam heating of samples from the first batch at the temperatures of 600°C, 700°C, 750°C and isothermal exposure time of 0 min, 10 min, 20 min, 30 min, 60 min, and 120 min. For comparative analysis, thermal heating of samples from the second batch was performed in a resistance laboratory furnace using the same time and temperature regimes. XRD analysis of samples showed the formation of lithium-zinc ferrites with greater homogeneous phase composition at lower values of temperature and time during RT synthesis compared to the samples obtained by thermal heating. Also, RT-synthesized ferrites are characterized by significantly higher values of saturation magnetization at all time and temperature regimes. It was established that a regime of RT synthesis at 750°C-30 min provides the formation of lithium-zinc ferrites with a high degree of final phase composition. [ABSTRACT FROM AUTHOR]

We tested the hypothesis that strength exercise after intermittent aerobic exercise might activate signaling pathways that regulate mitochondrial biogenesis (activation of the AMPK and p38 pathways; the expression of PGC-1α, NT-PGC-1α, TFAM, and VEGFA mRNA), protein synthesis (phosphorylation level of p70S6K1 and eEF2; the expression IGF-1Ea, IGF-1Ec (MGF), and REDD1 mRNA) and proteolysis (phosphorylation level of FOXO1; the expression of MURF1, MAFbx, and Myostatin mRNA) in trained skeletal muscles. Nine amateur endurance-trained athletes performed an intermittent aerobic cycling (70 min), followed by one-leg strength exercise (ES: four sets of knee extensions till exhaustion), while the other leg was resting (E). Gene expression and protein level were evaluated in samples from m. vastus lateralis taken before the exercise, 40 min, 5 and 22 h after the aerobic exercise. The phosphorylation level of the АСС (an endogenous marker of AMPK activity) and the expression of PGC-1α-related gene TFAM (a marker of mitochondrial biogenesis) were increased after E exercise and did not changed after ES exercise. The expression of PGC-1α and truncated isoform NT-PGC-1α was increased in both legs as well. Insulin concentration in blood was decreased significantly (7.5-fold) after aerobic exercise; the phosphorylation level of FOXO (a regulator of ubiquitin-related proteolysis) was decreased in both legs, which means that it was activated in both types of exercises; at the same time, the expression of the E3-ubiquitin ligase gene MURF1, its target, was only increased after E exercise. Neither aerobic or combined exercise had a significant effect on the regulation of protein synthesis: there were no changes in either expression of IGF-1Ea and IGF-1Ec(MGF) mRNA isoforms or the phosphorylation levels of markers of protein synthesis p70S6K1 and eEF2. Thus, the performance of strength exercise immediately after aerobic one prevented the activation of mitochondrial biogenesis in endurance-trained muscles: activation of AMPK pathway and the expression of TFAM are decreased, while protein synthesis regulation is not affected. At the same time, the strength exercise inhibited the expression of MURF1 gene (a marker of ubiquitin proteasome system), which was induced by aerobic exercise. We suggest that strength exercise performed immediately after intense intermittent aerobic exercise may have a negative effect on aerobic performance if used chronically. [ABSTRACT FROM AUTHOR]

The effect of the chain length of oligomer acrylic acid obtained in the presence of a low-molecularmass trithiocarbonate and the position of trithiocarbonate fragment (within the chain or at the chain end) on the process of emulsion polymerization of n-butyl acrylate and characteristics of the resulting dispersions has been studied for the first time. It has been found that, when using an oligomer with trithiocarbonate group located within the chain in the emulsion polymerization of n-butyl acrylate in a wide range of monomer-water phase compositions, triblock copolymers self-organizing in aqueous medium to give stable particles with the core-shell structure are formed. Oligomers with M ∼ (5-10) × 10 are optimal for synthesis of stable dispersions. In this case, block copolymers with the controlled length of hydrophobic block and a rather narrow MWD may be obtained. Thin films formed from these copolymers retain the structure of the initial dispersions on solvent removal. If the trithiocarbonate group in the oligomer is located at the chain end, the main polymerization product is a diblock copolymer. In this case, the formation of polymer-monomer particles occurs during a longer period of time, the control of MWD is weakened, and the dispersions of particles lose the aggregative stability after thin film formation. [ABSTRACT FROM AUTHOR]

Narrowly dispersed hydrophilic block and random copolymers of acrylic acid and N-isopropylacrylamide of various compositions and molecular masses are synthesized for the first time by controlled radical polymerization via the reversible addition-fragmentation chain-transfer mechanism. The copolymers are used for the synthesis of ternary copolymers with n-butyl acrylate. As shown by dynamic light scattering, the resulting amphiphilic copolymers can form stable dispersions in diluted aqueous solutions. It is found that the effective hydrodynamic radii of dispersion particles may be controlled via variation both in the primary structure of the ternary copolymer, i.e., the amount and sequence of hydrophilic and hydrophobic units, and in the external stimuli, i.e., the temperature and pH of a solution. [ABSTRACT FROM AUTHOR]

N-Chloro-1,4-benzoquinone imines reacted with arenethiols to give different products, depending on the conditions and initial quinone imine structure. N-(Arylsulfanyl)-1,4-benzoquinone imines were obtained as a result of nucleophilic substitution of the chlorine atom, and 1,4-benzoquinone imines containing an aryl-sulfanyl substituent in the quinoid ring were formed according to the radical mechanism. The reactions of N-chloro-1,4-benzoquinone imines with heterocyclic thiols afforded only the corresponding chlorine substitution products. [ABSTRACT FROM AUTHOR]

The construction of the piston groove seal of a volumetric hybrid energy-converting piston machine is proposed and investigated. A technique of assessing the overall performance of the proposed groove seal is developed and the influence of the basic construction and regime parameters on the overall performance of the seal is estimated. [ABSTRACT FROM AUTHOR]

N-Arenesulfonyl-1,4-benzoquinone imines reacted with acetylacetone to afford different products, depending on the isolation procedure. Crystallization from polar protic solvents gave N-[4-hydroxy- 3-(2-hydroxy-4-oxopent-2-en-3-yl)phenyl]arenesulfonamides and 6-(2-oxopropyl)-4-(arenesulfonamido)phenyl acetates, whereas N-(3-acetyl-2,6-dimethyl-1-benzofuran-5-yl)arenesulfonamides were isolated by crystallization from nonpolar aprotic solvents. [ABSTRACT FROM AUTHOR]

Effects of the amount of chemically dissimilar blocks (two or three) and their polarity on the aggregative behavior of АВ and АВС linear block copolymers of various compositions that are based on polystyrene, poly( n-butyl acrylate), and either poly(acrylic acid) or poly( tert-butyl acrylate) in bulk and in the nonselective solvent DMF are studied via differential scanning calorimetry and dynamic light scattering. АВ block copolymers composed of two chemically dissimilar blocks in the diluted solution in DMF are fully dispersed into macromolecular coils. However, the simultaneous incorporation of three incompatible blocks of different polarities (polystyrene, poly(acrylic acid), and poly( n-butyl acrylate)) into the copolymer is accompanied by a well-defined segregation of blocks in the nonselective solvent, regardless of the composition of the block copolymer and the length and sequence of blocks. This phenomenon makes itself evident as the formation of intermacromolecular aggregates in diluted solutions with a mean hydrodynamic radius of 60-120 nm that are stable in the range 10-60°C. A decrease in the level of the thermodynamic incompatibility of blocks (replacement of a poly(acrylic acid) polar block with a less polar poly( tert-butyl acrylate) block) or the selective improvement of solvent quality with respect to the polar block (the addition of LiBr to DMF) suppresses the segregation of blocks and may lead to the formation of a molecularly dispersed solution of the block copolymer. [ABSTRACT FROM AUTHOR]