Spectral Regularities of Viscoelastic Parameters of Whole Blood Exposed to Periodic Shear Stress.

Theoretic and experimental study of viscoelastic properties of the whole blood exposed to shear stress was carried out with acoustic resonance method based on the measurement of gain-frequency characteristics of resonating needle in an ARP-01M piezoelectric thromboelastograph (Mednord). The study revealed regularities in the changes of viscoelastic parameters of the whole blood within 0-80 kHz frequency range of shear vibrations. In this frequency range, the elastic (storage) modulus G' reflecting blood elasticity increased with frequency and significantly contributed to the complex viscosity coefficient. The revealed gain-frequency regularities open the vista to employ the acoustic resonance method to determine the viscoelastic parameters of the whole blood and their coagulation-induced changes in the wide frequency range of shear vibrations.

Electrophysiological Properties of Rat Vestibular Labyrinth and Their Effect on Parameters of Transmitted Voltage Pulses.

We propose a new approach to optimization of electrical stimulation of the vestibular nerve and improving the transfer function of vestibular implant. A mathematical model of the vestibular organ is developed based on its anatomy, the model premises, 3D-analysis of MRI and CT images, and mathematical description of physical processes underlying propagation of alternating electric current across the tissues of vestibular labyrinth. This approach was tested in vitro on the rat vestibular apparatus and had been examined anatomically prior to the development of its mathematical model and equivalent electrical circuit. The experimental and theoretical values of changes of the gain-phase characteristics of vestibular tissues in relation to location of the reference electrode obtained in this study can be used to optimize the electrical stimulation of vestibular nerve.