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Search Results: 1 - 10 of 209428 matches for " Valery L. Shnyrov "
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Steady-state kinetics of Roystonea regia palm tree peroxidase  [PDF]
Laura Sánchez Zamorano, Nazaret Hidalgo Cuadrado, Patricia Pérez Galende, Manuel G. Roig, Valery L. Shnyrov
Journal of Biophysical Chemistry (JBPC) , 2012, DOI: 10.4236/jbpc.2012.31002
Abstract: Royal palm tree peroxidase (RPTP) has been isolated to homogeneity from leaves of Roystonea regia palm trees. The enzyme purification steps included homogenization, (NH4)SO4 precipitation, extraction of palm leaf colored compounds and consecutive chromatography on Phenyl-Sepharose, TSK-Gel DEAE-5PW and Superdex-200. The novel peroxidase was characterized as having a molecular weight of 48.2 ± 3.0 kDa and an isoelectric point pI 5.4 ± 0.1. The enzyme forms dimers in solution with approximate molecular weight of 92 ± 2 kDa. Here we investigated the steady-state kinetic mechanism of the H2O2-supported oxidation of different organic substrates by RPTP. The results of the analysis of the initial rates vs. H2O2 and reducing substrate concentrations were seen to be consistent with a substrate-inhibited Ping-Pong Bi-Bi reaction mechanism. The phenomenological approach used expresses the peroxidase Ping-Pong mechanism in the form of the Michaelis-Menten equation and affords an interpretation of the effects in terms of the kinetic parameters KmH2O2, KmAH2, kcat, KSIH2O2, KSIAH2 and of the microscopic rate constants k1 and k3 of the shared three-step peroxidase catalytic cycle. Furthermore, the concentration and time-dependences and the mechanism of the suicide inactivation of RPTP by hydrogen peroxide were studied kinetically with guaiacol as co-substrate. The turnover number (r) of H2O2 required to complete the inactivation of the enzyme was 2154 ± 100 and the apparent rate constants of catalysis 185 s–1 and 18 s–1.
Tubular immunostimulating complex based on cucumarioside A2-2 and monogalactosyldiacylglycerol from marine macrophytes
Eduard Y Kostetsky, Nina M Sanina, Andrey N Mazeika, Alexander V Tsybulsky, Natalia S Vorobyeva, Valery L Shnyrov
Journal of Nanobiotechnology , 2011, DOI: 10.1186/1477-3155-9-35
Abstract: The cucumarioside A2-2 - cholesterol - MGalDG ratio of 6:2:4 (by weight) was found to provide the most effective formation of TI-complexes and the minimum hemolytic activity in vitro. Tubules of TI-complexes have an outer diameter of about 16 nm, an inner diameter of 6 nm, and a length of 500 nm. A significant dilution by the buffer gradually destroyed the tubular nanoparticles. The TI-complex was able to increase the immunogenicity of the protein antigens from Yersinia pseudotuberculosis by three to four times.We propose an optimized methodology for the preparation of homogeneous TI-complexes containing only tubular particles, which would achieve reproducible immunization results. We suggest that the elaborated TI-complexes apply as a universal delivery system for different subunit antigens within anti-infectious vaccines and enhance their economic efficacy and safety.Immunostimulating complexes (ISCOMs) are a commonly known adjuvant that represents a supramolecular combination of saponins from Quillaja saponaria, cholesterol, and phosphatidylcholine. It has been shown that ISCOMs display high adjuvant activity against a broad range of bacterial and viral antigens [1-5]. However, the side effects of ISCOMs are their toxicity, caused by the presence of the hemolytic saponins of Q. saponaria [2,6], a consistently insufficient adjuvant activity, and the absence of a satisfactory method of preparing them for industrial applications [6-9]. The development of the ISCOMATRIX? adjuvant, based on purified saponin fractions from Quil A substantially overcomes these shortcomings [1,10]. However, we proposed principally new biologically active components, glycoglycerolipids and triterpene glycosides isolated from marine macrophytes and invertebrates, respectively, to modify and optimize ISCOM vehicles for microbial antigens. The immunologically inert phospholipid phosphatidylcholine (PC) of ISCOMs was replaced by glycolipid monogalactosyldiacylglycerol (MGalDG) from marine mac
The New Form of Mixed Economy with Rationing: Agent-Based Approach  [PDF]
Valery L. Makarov, Albert R. Bakhtizin
Open Journal of Social Sciences (JSS) , 2014, DOI: 10.4236/jss.2014.24019
Abstract: In the paper, we explore the rationing as a way to implement a variety of incentives for people’s activity. We assume that the population is divided into six social clusters with different incentives to work. The first social cluster (business oriented people) has standard incentive: getting profit. Other clusters’ members (state and military servants, scientists, art workers, priests, etc.) try to lift on the social stairs, getting higher rank. Having a position of a certain rank, a person obtains the possibility to consume goods according to fixed norms.
Plasma Oscillations in Layered Superconductors
Valery L. Pokrovsky
Physics , 1996, DOI: 10.1117/12.241743
Abstract: This is a Review of experimental observations and theoretical developments on the c-axis plasma oscillations in High-temperature superconductors.
Fast quantum noise in Landau-Zener transition
Valery L. Pokrovsky,Deqiang Sun
Physics , 2007, DOI: 10.1103/PhysRevB.76.024310
Abstract: We show by direct calculation starting from a microscopic model that the two-state system with time-dependent energy levels in the presence of fast quantum noise obeys the master equation. The solution of master equation is found analytically and analyzed in a broad range of parameters. The fast transverse noise affects the transition probability during much longer time (the accumulation time) than the longitudinal one. The action of the fast longitudinal noise is restricted by the shorter Landau-Zener time, the same as in the regular Landau-Zener process. The large ratio of time scales allows solving the Landau-Zener problem with longitudinal noise only, then solving the same problem with the transverse noise only and matching the two solutions. The correlation of the longitudinal and transverse noise renormalizes the Landau-Zener transition matrix element and can strongly enhance the survival probability, whereas the transverse noise always reduces it. Both longitudinal and transverse noise reduce the coherence. The decoherence time is inverse proportional to the noise intensity. If the noise is fast, its intensity at which the multi-quantum processes become essential corresponds to a deeply adiabatic regime. We briefly discuss possible applications of the general theory to the problem of the qubit decoherence and to the spin relaxation of molecular magnets.
Oscillations of Spherical and Cylindrical Shells
Serkan Erdin,Valery L. Pokrovsky
Physics , 2000, DOI: 10.1142/S021797920100721X
Abstract: We have found the complete spectrum and eigenstates for harmonic oscillations of ideal spherical and cylindrical shells, both being infinitely thin. The spectrum of the cylindrical shell has an infinite number of Goldstone modes corresponding to folding deformations. This infrared catostrophe is overcome by accounting for curvature-part of energy.
Superconducting Transition Temperature in Heterogeneous Ferromagnet-Superconductor Systems
Valery L. Pokrovsky,Hongduo Wei
Physics , 2003, DOI: 10.1103/PhysRevB.69.104530
Abstract: We study the shift of the the superconducting transition temperature $T_c$ in ferromagnetic-superconducting bi-layers and in a superconducting film supplied a square array of ferromagnetic dots. We find that the transition temperature in these two cases change presumably in opposite direction and that its change is not too small. We extend these results to multilayer structures. We predict that rather small external magnetic field $\sim 10$ Oe can change the transition temperature of the bilayer by 10% .
Spin Correlations in Quantum Wires
Chen Sun,Valery L. Pokrovsky
Physics , 2014, DOI: 10.1103/PhysRevB.91.161305
Abstract: We consider theoretically spin correlations in an 1D quantum wire with Rashba-Dresselhaus spin-orbit interaction (RDI). The correlations of non-interacting electrons display electron-spin resonance at a frequency proportional to the RDI coupling. Interacting electrons on varying the direction of external magnetic field transit from the state of Luttinger liquid (LL) to the spin density wave (SDW) state. We show that the two-time total spin correlations of these states are significantly different. In the LL the projection of total spin to the direction of the RDI induced field is conserved and the corresponding correlator is equal to zero. The correlators of two components perpendicular to the RDI field display a sharp ESR driven by RDI induced intrinsic field. In contrast, in the SDW state the longitudinal projection of spin dominates, whereas the transverse components are suppressed. This prediction indicates a simple way for experimental diagnostic of the SDW in a quantum wire.
Magnetic properties of a long, thin-walled ferromagnetic nanotube
Chen Sun,Valery L. Pokrovsky
Physics , 2013, DOI: 10.1016/j.jmmm.2013.12.011
Abstract: We consider magnetic properties of a long, thin-walled ferromagnetic nanotube. We assume that the tube consists of isotropic homogeneous magnet whose spins interact via the exchange energy, the dipole-dipole interaction energy, and also interact with an external field via Zeeman energy. Possible stable states are the parallel state with the magnetization along the axis of the tube, and the vortex state with the magnetization along azimuthal direction. For a given material, which of them has lower energy depends on the value \gamma=R^2d/(L \lambda_x^2), where R is the radius of the tube, d is its thickness, L is its length and \lambda_x is an intrinsic scale of length characterizing the ration of exchange and dipolar interaction. At \gamma<1 the parallel state wins, otherwise the vortex state is stable. A domain wall in the middle of the tube is always energy unfavorable, but it can exist as a metastable structure. Near the ends of a tube magnetized parallel to the axis a half-domain structure transforming gradually the parallel magnetization to a vortex just at the edge of the tube is energy favorable. We also consider the equilibrium magnetization textures in an external magnetic field either parallel or perpendicular to the tube. Finally, magnetic fields produced by a nanotube and an array of tubes is analyzed.
A Lie algebra attached to a projective variety
Eduard Looijenga,Valery L. Lunts
Mathematics , 1996, DOI: 10.1007/s002220050166
Abstract: Each choice of a K\"ahler class on a compact complex manifold defines an action of the Lie algebra $\slt$ on its total complex cohomology. If a nonempty set of such K\"ahler classes is given, then we prove that the corresponding $\slt$-copies generate a semisimple Lie algebra. We investigate the formal properties of the resulting representation and we work things out explicitly in the case of complex tori, hyperk\"ahler manifolds and flag varieties. We pay special attention to the cases where this leads to a Jordan algebra structure or a graded Frobenius algebra.
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