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This study aims to develop a viscoelastic database for muscles (VM: vastus medialis and Sr: sartorius) and subcutaneous adipose tissue with multifrequency magnetic resonance elastography (MMRE) coupled with rheological models. MMRE was performed on 13 subjects, at 70-90-110 Hz, to experimentally assess the elastic properties (μ) of passive and active (20% MVC) muscles. Then, numerical shear modulus (μ) and viscosity (η) were calculated using three rheological models (Voigt, Zener, Springpot). The elastic properties, obtained with the Springpot model, were closer to the experimental data for the different physiological tissues (μ_{Springpot_VM_Passive} = 3.67 ± 0.71 kPa, μ_{Springpot_Sr} = 6.89 ± 1.27 kPa, μ_{Springpot_Adipose Tissue} = 1.61 ± 0.37 kPa) and at different muscle states (μ_{Springpot_VM_20%MVC} = 11.29 ± 1.04 kPa). The viscosity parameter increased with the level of contraction (η_{_VM_Passive_Springpot} = 4.5 ± 1.64 Pa.s versus η_{_VM_20%MVC_Springpot} = 12.14 ± 1.47 Pa.s) and varied with the type of muscle. (η_{_VM_Passive_Springpot} = 4.5 ± 1.64 Pa.s versus η_{_Sr_Springpot} = 6.63 ± 1.27 Pa.s). Similar viscosities were calculated for all tissues and rheological models. These first physiologically realistic viscoelastic parameters could be used by the physicians to better identify and monitor the effects of muscle disorder, and as a database for musculoskeletal model.

The traveling wave is the most important phenomenon in cochlear macromechanics. The behaviors of the traveling wave that greatly alter the auditory discrimination, are tightly related with the mechanical properties of the basilar membrane (BM) and its surrounding lymph. As an addition to the blanks of related researches, this paper focuses on some of the key parameters that affect the cochlear response most: the BM stiffness, damping parameters and the fluid viscosity. The influence of these parameters on the traveling wave is discussed, based on our former developed 2D finite element hydrodynamic cochlear model. Moreover, the traveling wave velocity and its transmitting time are calculated based on the simulating results. Although generally a rapid fall of the velocity from the cochlear base to the characteristic frequency (CF) location is confirmed, our quantitative analysis also indicates the traveling wave velocity may be both location and frequency dependent.

Tissue elasticity and viscosity are always associated with pathological changes. As a new imaging method, ultrasound vibro-acoustic imaging is developed for quantitatively measuring tissue elasticity and viscosity which have important significance in early diagnosis of cancer. This paper developed an ultrasound vibro-acoustic imaging research platform mainly consisting of excitation part and detection part. The excitation transducer was focused at one location within the medium to generate harmonic vibration and shear wave propagation, and the detection transducer was applied to detect shear wave at other locations along shear wave propagation path using pulse-echo method. The received echoes were amplified, filtered, digitized and then processed by Kalman filter to estimate the vibration phase. According to the phase changes between different propagation locations, we estimated the shear wave speed, and then used it to calculate the tissue elasticity and viscosity. Preliminary phantom experiments based on this platform show results of phantom elasticity and viscosity close to literature values. Upcoming experiments are now in progress to obtain quantitative elasticity and viscosity in vitro tissue.

In this paper, the mathematical model of distribution of the injected compound in biological liquid flow has been described. It is considered that biological liquid contains a few phases such as water, peptides and cells. The injected compound (for example, photosensitizer) can interact with peptides and cells. At the time, viscosity of the biological liquid depends on pathology present in organism. The obtained distribution of the compound connects on changes of its fluorescence spectra which are registered during fluorescent diagnostics of tumors. It is obtained that the curves do not have monotonic nature. There is a sharp curves decline in the first few seconds after injection. Intensivity of curves rises after decreasing. It is especially pronounced for wavelength 590nm and 580nm (near the “transparency window” of biological tissues). Time of inflection point shifts from 8.4s to 6.9s for longer wavelength. However, difference between curves is little for different viscosity means of the biological liquid. Thus, additional pathology present in organism does not impact to the results of in vivo biomedical investigations.