Characterization of Aluminum Foam Impact Response

Strength of Materials - The paper addresses the investigation of high-strain rate compressive behavior of Al foams subjected to impact at the intermediate striking velocity ranged from 40 to...     

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.     

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.     

Photoinduced recovery of gamma-irradiated fluoride glasses

Radiation-induced changes in the optical properties of fluoride glasses (FGs) were studied on samples of zirconium fluoride and aluminum fluoride based compositions gamma-irradiated to a total dose of 1.2 MGy. Upon exposure, the fundamental absorption edge smears and shifts toward longer wavelengths. The FGs studied exhibit self-recovery of the optical properties, whereby the radiation-induced absorption decreases in the course of storage without action of any external factors. Photostimulated recovery of the optical properties of the gamma-irradiated FGs was studied in the range of light wavelengths from 400 to 1200 nm at a light intensity of 1–3 mW/cm². The maximum rate of recovery for both zirconium and aluminum fluoride based glasses was observed for the photoannealing at 600 nm.     

Precision Spectrometric Determination of Th and Pu in Solutions with Arsenazo III Using Internal Standardization

A spectrophotometric procedure with internal standardization was suggested for precision determination of the concentrations of Th and Pu in the form of colored complexes with arsenazo III in nitric acid solutions. The sensitivity of the method was significantly improved owing to the use of colored complexes. The optical density optimum (0.3-0.5) of the solutions for spectrophotometric measurements can be achieved at concentrations in solution of the element analyzed as low as (2-3) ×10^-6 M, at the arsenazo and HNO₃ concentrations of 1 ×10^-4 and 6 M, respectively. With this composition of the solution, the relative rms deviation of the results for a single run is no greater than 0.15 and 0.3% for thorium and plutonium, respectively.