Determination of homocysteine and other low-molecular-weight amino thiols in blood plasma

A current approach to determining low-molecular-weight amino thiols (cysteine, homocysteine, and glutathione) in model samples and blood plasma is considered. Procedures for determining 2–100 μM homocysteine in blood plasma with the use of microcolumn chromatography and capillary electrophoresis were developed. Photometric and fluorimetric detection techniques were used to identify amino thiols. Monobromobimane and 5-iodoacetamidofluorescein were used as labels. Mass spectrometry was used to confirm the structures of test amino thiol derivatives.     

Integration ofD-dimensional cosmological models with two factor spaces by reduction to the generalized Emden-Fowler equation

The D-dimensional cosmological model on the manifold M=R×M₁×...×M_n, describing the evolution of Einstein factor spaces M_i in the presence of a multicomponent perfect fluid source, is considered. The barotropic equation of state for the mass-energy densities and pressures of the components is assumed in each space. Where the number of non-Ricci-flat factor spaces and the number of perfect fluid components are both equal to two, the Einstein equations for the model are reduced to the generalized Emden-Fowler (second-order ordinary differential) equation, which has been recently investigated by Zaitsev and Polyanin using discrete-group analysis. We generate new integrable cosmological models using the integrable classes of this equation and present the corresponding metrics. The method is demonstrated for the special model with Ricci-flat spaces M₁ and M₂ and a two-component perfect fluid source. Translated from Teoreticheskaya i Matematicheskaya Fizika. Vol. 114, No. 3, pp. 454–469, March, 1998.     

Study of the plasma potential evolution during ECRH in the T-10 tokamak and TJ-II stellarator

Comparison of the plasma electric potential evolution in the T-10 tokamak and TJ-II stellarator was performed. The core potential was measured by the heavy-ion beam probing and the edge potential was measured by Langmuir probe. The intrinsic potentials in both devices are different in sign, positive in TJ-II low-density discharge and negative in T-10 higher-density discharges, but during ECRH they evolve similarly: the potential becomes more positive, and increase of ECRH power leads to stronger rise of core potential. Presented at the Workshop “Electric Fields, Structures and Relaxation in Edge Plasmas”, Tarragona, Spain, July 3–4, 2005.     

Brane World Corrections to Newton’s Law

We discuss possible variations of the effective gravitational constant with length scale, predicted by most of alternative theories of gravity and unified models of physical interactions. After giving a brief general exposition, we review in more detail the predicted corrections to Newton’s law of gravity in diverse brane world models. We consider various configurations in 5 dimensions (flat, de Sitter and AdS branes in Einstein and Einstein–Gauss–Bonnet theories, with and without induced gravity and possible incomplete graviton localization), 5D multi-brane systems and some models in higher dimensions. A common feature of all models considered is the existence of corrections to Newton’s law at small radii comparable with the bulk characteristic length: at such radii, gravity on the brane becomes effectively multidimensional. Many models contain superlight perturbation modes, which modify gravity at large scale and may be important for astrophysics and cosmology.     

A kinematical study of Kirchhoff-Rayleigh flow

Summary A method of calculating the separated flow of a viscous fluid is proposed, which allows to split up properly the boundary condition problem from the viscous phenomena. The theory is developed for the flow past a plate and yields wakes of finite extension having an underpressure which depends directly on the amount of vorticity diffusion and dissipation occurring in the fluid. Application of the method to real flows shows good agreement between the calculated and the measured velocity distributions in front of the plate and in the wake.

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Résumé Une méthode de calcul de l'écoulement décollé d'un fluide visqueux est proposée qui permet de séparer clairement le problème aux limites des phénomènes visqueux. La théorie est développée pour l'écoulement autour d'une plaque et donne des sillages de longueur finie ayant une dépression de culot directement dépendante de l'intensité de la diffusion et dissipation de la vorticité se produisant dans le fluide. L'application de la méthode à des écoulements réels montre une bonne concordance entre les répartitions de vitesse calculées et mesurées sur le devant de la plaque et dans le sillage.

     

Spontaneously broken symmetries in gravitational fields

In the present work we study models with material and gravitational fields unified in a self-consistent manner [2, 3]. We use a semiclassical approach, where the gravitational field is classical, but the other fields may be quantum ones. The mechanism of spontaneous symmetry breaking is due to the conformai generalization of the Higgs fields in a curved spacetime. Gravitation will be considered as a gauge field and then in the usual Einstein version.     

Investigation of ultrafast processes in photoexcited bismuth by broadband probing in the wavelength range 0.4–0.9 μm

The decay of the photoexcited state of a bismuth single crystal is investigated in the wavelength range from 400 to 900 nm by means of femtosecond laser reflection spectroscopy. Oscillations produced by coherent fully symmetric A _1g phonons have been detected in the photoinduced response, along with a relaxation component. The dynamics of the electronic subsystem of the crystal is shown to be characterized by three values of the decay time: 1 ps, 7 ps, and ∼1 ns. The spectral dependence of the reflectivity oscillation amplitude has been measured; the possible cause of the shape of the derived curve is described.     

Debye–Waller Factor in Neutron Scattering by Ferromagnetic Metals

We obtain an expression for the neutron scattering cross section in the case of an arbitrary interaction of the neutron with the crystal. We give a concise, simple derivation of the Debye–Waller factor as a function of the scattering vector and the temperature. For ferromagnetic metals above the Curie temperature, we estimate the Debye–Waller factor in the range of scattering vectors characteristic of polarized magnetic neutron scattering experiments. In the example of iron, we compare the results of harmonic and anharmonic approximations.     

W Boson production cross section at the Large Hadron cCllider with Omicron(alpha(2)(s)) corrections

We compute the Omicron(alpha(2)(s)) QCD corrections to the fully differential cross section pp --> WX --> lnuX, retaining all effects from spin correlations. The knowledge of these corrections makes it possible to calculate with high precision the boson production rate and acceptance at the CERN Large Hadron Collider (LHC), subject to realistic cuts on the lepton and missing energy distributions. For certain choices of cuts we find large corrections when going from next-to-leading order (NLO) to next-to-next-to-leading order in perturbation theory. These corrections are significantly larger than those obtained by parton-shower event generators merged with NLO calculations. Our result may be used to assess and significantly reduce the QCD uncertainties in the many studies of boson production planned at the LHC.