The interaction between ultrasonic waves and biological tissues is the cause of cavitation phenomena. A primary scope of this paper was to set-up a measurement system for the generation of cavitation by means of forcing a low frequency (20 kHz). From the spectra and power density was evident the presence of the random component associated to the noise of cavitation was evident. For the estimate of this component the technique ARMA spectral was particularly effective. The average lifetime of transient cavitation bubbles estimated from the time constant via the ARMA spectrum, was found to be in agreement with the data in the literature.

One of the methods of medical navigation, applied for positioning of instruments inside the patient's body during investigation or surgery, is electromagnetic one. The great advantage of this method is a possibility of positioning inside the patient's body. Its shortcomings are: sensitivity to the presence of objects disturbing the magnetic field distribution, i.e. conducting and ferromagnetic objects in the operating space and a relatively small area of high accuracy measurement. The works presented in this paper are aimed to prevent or limit these disadvantages. The improved accuracy of measurement can be achieved thanks to the introduction of an additional reference channel and performance of numeric simulations enabling optimal choice of the system of magnetic field generation. The disturbing influence of conducting and ferromagnetic objects on the system accuracy have been simulated using the finite element method (FEM). Some methods of limiting these disturbances have been proposed on the basis of the results obtained.

Frictional behaviors of articulating surfaces have been recognized as critical factors affecting their service life because these behaviors play very important role on wear of ultrahigh molecular weight polyethylene (UHMWPE) which causes failure of artificial joint replacements. The objective of this study is to determine temperature rise as a function of sliding time and maximum load for the articulating surfaces of vitamin E blended UHMWPE acetabular component paired with a cobaltchromium (CoCrMo) femoral component. Additionally frictional torque between the bearing surfaces was measured and friction coefficient was calculated. Frictional measurements of the joints were carried out on a custom made hip joint friction simulator. The prostheses were in 28 mm diameter. Applied static loads were changed from 200 N to 1500 N. In flexion-extension plane, a simple harmonic oscillatory motion between ±24o was applied to the UHMWPE acetabular component. The period of motion was 1 Hz and the tests were run up to 11000 cycles. Temperature rise in acetabular and femoral component is recorded with embedded thermocouples. Also the tests are repeated with UHMWPE acetabular component. The results are compared in terms of UHMWPE and vitamin E blended UHMWPE.

Measurement of signals from biological objects usually requires complex and expensive system. This paper presents a simple, cost effective, computer controlled modular systems consisting of self developed modules and modules from a few vendors and own software developed in LabVIEW. The system enables multichannel data acquisition with sampling frequency a few kHz with nearly unlimited lengths, triggering and pretriggering records. The records are stored in signal database and processed by software in PC using various advanced digital signal processing methods for recovering distorted signal. The system was developed and has been used for biological experiments on rats focused on evoked potentials.

Executable biology at various levels of spatial scale is becoming increasingly important in order to understand the complexity exhibited in living systems. This paper describes how a multiscale systems approach can be used to integrate these models of behaviour to provide an insight into the development of cardiac valves. In particular, simulations of epithelial to mesenchymal transition using a Cellular Potts model are shown to demonstrate cell adhesion and imitate faithfully the in vivo process. As a consequence, this work also shows the importance of measurement of surface energy of adjacent cells and its effect on systemic behaviour.