Time filter

Source Type

Pipin V.V.,Russian Academy of Sciences | Ragulskaya M.V.,Russian Academy of Sciences | Chibisov S.M.,Russian University of People Friendship
Bulletin of Experimental Biology and Medicine | Year: 2010

The paper analyzes theoretical models of the adaptive modes of generation and stability of human heart as a nonlinear point source. The analysis encompasses only ECG time-domain dynamics. To solve the general problem of the study of the adaptive changes of the cardiosignal under the action of external periodic force and parametric noise, a new dynamic model is proposed, which incorporates two control physical parameters: power of signal generation and coefficient of diffuse signal scattering. For the entire set of parameters, the examined modeled nonlinear system demonstrated a number of various performance modes ranging from steady-state periodic and quasi-periodic states to chaos. The model showed that variations in cosmic, geophysical, and weather conditions in the frequency range of 0.1-0.9 Hz produce the greatest biotropic influence. © 2010 Springer Science+Business Media, Inc.

Blagonravov M.L.,Russian University of People Friendship | Frolov V.A.,Russian University of People Friendship | Azova M.M.,Russian University of People Friendship | Goryachev V.A.,Russian University of People Friendship
Bulletin of Experimental Biology and Medicine | Year: 2013

The specific features of circadian rhythm of BP were investigated in freely moving male SHR rats using telemetry monitoring technique. BP was recorded in the abdominal aorta according to 24-h/4-month schedule. The data were obtained from 22, 26, 30, 34, and 38-week-old animals. Normotensive Wistar rats (22 weeks) served as the control. It was found that the mean 24-h, daytime, and nighttime systolic and diastolic BP in hypertensive rats significantly surpassed the control throughout the observation period and practically did not change during prolonged hypertension. Some prognostically negative changes in the circadian rhythm of the basic hemodynamics system parameters appeared with time. For instance, the maximum 24-h systolic BP significantly increased in comparison with the initial level. © 2013 Springer Science+Business Media New York.

Discover hidden collaborations