Biomedical subjects

A V Milovanov

Publications and source records attributed to A V Milovanov.

4 recordsLinked to original sources

PubMed2006

Superdiffusion and viscoelastic vortex flows in a two-dimensional complex plasma.

Viscoelastic vortical fluid motion in a strongly coupled particle system has been observed experimentally. Optical tracking of particle motion in a complex plasma monolayer reveals high grain mobility and large scale vortex flows coexistent with partial preservation of the global hexagonal lattice structure. The transport of particles is superdiffusive and ascribed to Lévy statistics on short time scales and to memory effects on the longer scales influenced by cooperative motion. At these longer time scales, the transport is governed by vortex flows covering a wide spectrum of temporal and spatial scales.

Journal Article↗

PubMed2001

"Strange" Fermi processes and power-law nonthermal tails from a self-consistent fractional kinetic equation.

This study advocates the application of fractional dynamics to the description of anomalous acceleration processes in self-organized turbulent systems. Such processes (termed "strange" accelerations) involve both the non-Markovian fractal time acceleration events associated with a generalized stochastic Fermi mechanism, and the velocity-space Levy flights identified with nonlocal violent accelerations in turbulent media far from the (quasi)equilibrium. The "strange" acceleration processes are quantified by a fractional extension of the velocity-space transport equation with fractional time and phase space derivatives. A self-consistent nonlinear fractional kinetic equation is proposed for the stochastic fractal time accelerations near the turbulent nonequilibrium saturation state. The ensuing self-consistent energy distribution reveals a power-law superthermal tail psi(epsilon) proportional to epsilon(-eta) with slope 6 or =eta< or =7 depending on the type of acceleration process (persistent or antipersistent). The results obtained are in close agreement with observational data on the Earth's magnetotail.

Journal Article↗

PubMed2001

Stochastic dynamics from the fractional Fokker-Planck-Kolmogorov equation: large-scale behavior of the turbulent transport coefficient.

The formulation of the fractional Fokker-Planck-Kolmogorov (FPK) equation [Physica D 76, 110 (1994)] has led to important advances in the description of the stochastic dynamics of Hamiltonian systems. Here, the long-time behavior of the basic transport processes obeying the fractional FPK equation is analyzed. A derivation of the large-scale turbulent transport coefficient for a Hamiltonian system with 11 / 2 degrees of freedom is proposed in connection with the fractal structure of the particle chaotic trajectories. The principal transport regimes (i.e., a diffusion-type process, ballistic motion, subdiffusion in the limit of the frozen Hamiltonian, and behavior associated with self-organized criticality) are obtained as partial cases of the generalized transport law. A comparison with recent numerical and experimental studies is given.

Journal Article↗

PubMedDate not supplied

[Cardiac tamponade as a complication of central line catheterization in newborns].

Two cases with cardiac tamponade in neonates, one of which eventuated in death, are presented. The total tamponade rate was 0.27%. Several hours after catheterization patients suddenly developed bradycardia, hypotension, and signs of decompensation, all within an hour. One patient died and the diagnosis was made at autopsy. In the other patient ultrasonography showed a clear echo-free space between the epicardium and pericardium, with the tip of the catheter in contact with the atrial wall. Percutaneous pericardiocentesis was performed under cardiographic guidance; 11 ml of hemorrhagic fluid containing 26 mmol/liter glucose were aspirated. The catheter tip was then repositioned to the vena cava superior. Hemodynamic status rapidly improved and this patient survived. A review of relevant publications is offered.

Cardiac Tamponade↗