Rotating vortex dipoles in ferromagnets

Vortex-antivortex pairs are localized excitations and have been found to be spontaneously created in magnetic elements. In the case that the vortex and the antivortex have opposite polarities the pair has a nonzero topological charge, and it behaves as a rotating vortex dipole. We find theoretically, and confirm numerically, the form of the energy as a function of the angular momentum of the system and the associated rotation frequencies. We discuss the process of annihilation of the pair which changes the topological charge of the system by unity while its energy is monotonically decreasing. Such a change in the topological charge affects profoundly the dynamics in the magnetic system. We finally discuss the connection of our results with Bloch Points (BP) and the implications for BP dynamics.Comment: 6 pages, 2 figure

Contributions of spontaneous phase slippage to linear and non-linear conduction near the Peierls transition in thin samples of o-TaS_3

In the Peierls state very thin samples of TaS_3 (cross-section area \sim 10^{-3} mkm^2) are found to demonstrate smearing of the I-V curves near the threshold field. With approaching the Peierls transition temperature, T_P, the smearing evolves into smooth growth of conductance from zero voltage interpreted by us as the contribution of fluctuations to the non--linear conductance. We identify independently the fluctuation contribution to the linear conductance near T_P. Both linear and non-linear contributions depend on temperature with close activation energies \sim (2 - 4) x 10^3 K and apparently reveal the same process. We reject creep of the {\it continuous} charge-density waves (CDWs) as the origin of this effect and show that it is spontaneous phase slippage that results in creep of the CDW. A model is proposed accounting for both the linear and non-linear parts of the fluctuation conduction up to T_P.Comment: 6 pages, 5 Postscript figure, RevTeX, accepted for publication in PR

Human recombinant erythropoietin gradient dosage influence on ischemic and reperfusion liver injury

We investigate influence of human recombinant erythropoietin different dosage on blood flow velocity and morphological changes in liver during ischemic and reperfusion injury. It was proved what optimal preconditioning dosage is 50 IU/k

The 3d-to-4s-by-2p highway to superconductivity in cuprates

High-temperature superconductors are nowadays found in great variety and hold technological promise. It is still an unsolved mystery that the critical temperature T_c of the basic cuprates is so high. The answer might well be hidden in a conventional corner of theoretical physics, overlooked in the recent hunt for exotic explanations of new effects in these materials. A forgotten intra-atomic s-d two-electron exchange in the Cu atom is found to provide a strong (~eV) electron pairing interaction. A Bardeen-Cooper-Schrieffer approach can explain the main experimental observations and predict the correct d_{x^2-y^2} symmetry of the gap.Comment: 4 pages, 3 figures, LaTeX2

Study of the microcirculation level in bone with osteoporosis and osteoporotic fractures during therapy with recombinant erythropoietin, rosuvastatin and their combinations

The experiment was carried out in female white Wistar rats. The effects of recombinant erythropoietin, rosuvastatin and their combination were investigated based on the blood supply to the bone after a modelled experimental osteoporosis. It was found that the studied drugs prevent decrease of bone microcirculation in cases of osteoporosis and in callus tissue in experimental osteoporotic fractures, positively influencing the course of reparative regeneration of bone tissu

Classical and relativistic dynamics of supersolids: variational principle

We present a phenomenological Lagrangian and Poisson brackets for obtaining nondissipative hydrodynamic theory of supersolids. A Lagrangian is constructed on the basis of unification of the principles of non-equilibrium thermodynamics and classical field theory. The Poisson brackets, governing the dynamics of supersolids, are uniquely determined by the invariance requirement of the kinematic part of the found Lagrangian. The generalization of Lagrangian is discussed to include the dynamics of vortices. The obtained equations of motion do not account for any dynamic symmetry associated with Galilean or Lorentz invariance. They can be reduced to the original Andreev-Lifshitz equations if to require Galilean invariance. We also present a relativistic-invariant supersolid hydrodynamics, which might be useful in astrophysical applications.Comment: 22 pages, changed title and content, added reference

Pharmacological correction of retinal ischemia/reperfusion by minoxidil

The objective of this paper was to increase the effectiveness of pharmacological correction of retinal ischemia-reperfusion by using minoxidil. Minoxidil at a dose of 0.5 mg/kg of rat mass protects the retina from ischemic-reperfusion injury. Protective effects of minoxidil are carried out by a preconditioning action, as evidenced by the lack of positive effects with the administration of glibenclamid

Fermion Analogy for Layered Superconducting Films in Parallel Magnetic Field

The equivalence between the Lawrence-Doniach model for films of extreme type-II layered superconductors and a generalization of the back-scattering model for spin-1/2 electrons in one dimension is demonstrated. This fermion analogy is then exploited to obtain an anomalous $H_{\parallel}^{-1}$ tail for the parallel equilibrium magnetization of the minimal double layer case in the limit of high parallel magnetic fields $H_{\parallel}$ for temperatures in the critical regime.Comment: 11 pages of plain TeX, 1 postscript figur