Re-entrant activity and its control in a model of mammalian ventricular tissue

We characterize the meander of re-entrant excitation in a model of a sheet of mammalian ventricular tissue, and its control by resonant drift under feedback driven stimulation. The Oxsoft equations for excitability in a guinea pig single ventricular cell were incorporated in a two dimensional reaction-diffusion system to model homogeneous, isotropic tissue with a plane wave conduction velocity of 0.35 m s-1. Re-entrant spiral wave solutions have a spatially extended transient motion (linear core) that settles down into rotation with an irregular period of 100-110 ms around an irregular, multi-lobed spiky core. In anisotropic tissue this would appear as a linear conduction block. The typical velocity of drift of the spiral wave induced by low amplitude resonant forcing is 0.4 cm s-1.     

Nanofabrication with Pulsed Lasers

An overview of pulsed laser-assisted methods for nanofabrication, which are currently developed in our Institute (LP3), is presented. The methods compass a variety of possibilities for material nanostructuring offered by laser–matter interactions and imply either the nanostructuring of the laser-illuminated surface itself, as in cases of direct laser ablation or laser plasma-assisted treatment of semiconductors to form light-absorbing and light-emitting nano-architectures, as well as periodic nanoarrays, or laser-assisted production of nanoclusters and their controlled growth in gaseous or liquid medium to form nanostructured films or colloidal nanoparticles. Nanomaterials synthesized by laser-assisted methods have a variety of unique properties, not reproducible by any other route, and are of importance for photovoltaics, optoelectronics, biological sensing, imaging and therapeutics.     

Effect of flameout on Combustion of small particles in an acoustically oscillating flow

Combustion of magnesium and titanium particles in an acoustically oscillating flow is experimentally studied for the case where the particle dimensions are smaller than the amplitude of gas displacement in an acoustic wave. An increase in the combustion time of magnesium particles and a decrease in the combustion time of titanium particles upon application of acoustic vibrations is found. Characteristic features of fluctuations of the intensity of the luminous flux of a burning magnesium particle as a response to vapor-phase burning of a metal drop to an external acoustic action are revealed. An explanation of the shape of registered fluctuations is offered on the basis of an assumption about flame-front blowoff from the frontal point of the drop. Conditions necessary for flameout in an oscillating flow and effects that can be induced by flameout from the drop in the case of burning of sprayed fuels in intermittent burning devices are discussed. Translated fromFizika Goreniya i Vzryva, Vol. 36, No. 2, pp. 10–16, March–April, 2000.     

The use of laser and phototherapy in the comprehensive treatment of malignant tumors and leukemia in children

The report deals with the development of procedures, evaluation of laser application and prevention of complications involved in intensive chemoradiation therapy of neoplasms of hemopoietic and lymphoid tissue in childhood. The clinical data on 548 patients, aged 2 months-15 years, with leukemia and solid tumor were evaluated. Laser application for treatment of different complications of chemoradiation therapy of pediatric leukemia proved a valuable innovation. It had a pronounced antiinflammatory and analgetic effect, promoted tissue regeneration processes and cut down the duration of complication treatment drastically.