Early and late postinfarct dilatation of the left ventricle: the connection to electrophysiological disorders and the risk of developing ventricular tachyarrhythmias

The aim of the study was to discover determinants of the onset of life threatening ventricular tachyarrhythmia. 102 patients with acute myocardial infarction and 32 patients with postinfarction cardiosclerosis were examined. The data gained at programmed ventricular stimulation, high resolution ECG, Holter ECG monitoring, spectral analysis of cardiac rhythm variability and two-dimension echocardiography proved the importance of early postinfarction left ventricular dilatation in the onset of electrical cardiac instability, establishment of anatomic substrate of monomorphic ventricular tachycardias, low variability of cardiac rhythm. The findings evidence that MI patients with late ventricular potentials and end-diastolic left ventricular index above 100 ml/m2 in subacute period may be considered as a group of high risk in need of individual approach and further therapy. The discovered lowering of informative value of non-invasive methods in patients late after MI dictates the necessity of new approaches to detection of electrophysiological disturbances and sudden death risk in registration of postinfarction dilatation of the heart.     

Laser with rapid tuning of the spectrum shape

We have studied a laser system with quick electronic tuning of the spectrum shape and continuous distribution. The proposed method is based on separate control of phase and amplitude spatial distributions of resonator transmittance. Evolution of the spectral function of the diffractively coupled dispersive resonators and the model for the formation of the resonator with the spectral function given by its moments are studied theoretically. The synthesis of continuous spectra is investigated experimentally in the laser with a novel control element including a spatial acousto-optic modulator and a tunable lens telescope.     

Small-angle neutron scattering investigation of the substructure of nickel irradiated with fast neutrons

The method of small-angle neutron scattering has been used to investigate the samples of pure nickel before and after irradiation with fast neutron fluences of Φ = 10¹⁸, 10¹⁹, and 10²⁰ cm^?2 (E _n ≥ 0.1 MeV). It has been found that the substructure of the samples consists of vacancy clusters with two characteristic sizes of 2.5–4 and ～7 nm. The sizes of precipitates weakly depend on fast neutron fluence. The magnitude of their density is on the order of 10²² and 10¹⁹ m^?3, respectively, and increases by three to ten times as the fluence grows.     

Neodymium-calcium cobaltates: Features of synthesis,phase composition,activity and selectivity in partial methane oxidation

Nd_{2 ? x} Ca _x CoO_{4 ± δ}-based materials demonstrated high effectiveness in partial methane oxidation into synthesis gas with almost 100% selectivity. It has been determined that Nd_{2 ? x} Ca _x CoO_{4 ± δ} materials synthesized via the solid-state or cryochemical methods are single-phase in the range of 0.6 ≤ x ≤ 1 at a synthesis temperatures of 1100–1200°C. Synthesis at t ≤ 1100°C allows to prepare solid solutions in the range of 0.9 < x < 1.05.     

Determination of the Complex Permittivity of Materials by a Modified Resonator Method Based on the Theory of Small Perturbations Using a Resonator of the Reflective Type

Journal of Communications Technology and Electronics - A modified resonator method for determining the complex permittivity of materials based on the theory of small perturbations where a resonator...     

Ferromagnetic semiconducting materials: Methods of studies and control of parameters (Review)

Methods used for designing and controlling parameters of prototypes of ferromagnetic semicon-ducting materials are described. Examples of applications of the above methods are given. The up-to-date ferromagnetic semiconductor design level for spin applications is briefly considered.     

Regularization of space-time integral equations in the problem of diffraction of electromagnetic pulses by N slots

Space-time integral equations describing diffraction of ultrashort electromagnetic pulses by slots in a screen located on a media interface are solved. The solution is based on separation of the static components of the kernels of the integral equations and the subsequent application of the collocation method.     

Construction of maximum cycles in faulty binary hypercubes

Consideration was given to the following problem. In the binary hypercube, given is a Hamiltonian cycle with faulty edges, or vertices, or both. Needed is to construct a length-maximum cycle without faulty components of the hypercube. The cycles are defined by the ring sequences of the weights of the hypercube edges belonging to them. The discussion was based on the example of a binary 4-dimensional hypercube.Translated from Avtomatika i Telemekhanika, No. 4, 2005, pp. 141–155.Original Russian Text Copyright © 2005 by Parkhomenko.This paper was recommended for publication by P.Yu. Chebotarev, a member of the Editorial Board