[Computer modeling of the area of carotid endarterectomy with patches of various forms]. / Sposob komp'yuternogo modelirovaniya zony klassicheskoi karotidnoi endarterektomii s primeneniem zaplat razlichnoi formy.

OBJECTIVE: To describe geometric models of carotid artery bifurcation and computer modeling of carotid endarterectomy (CEA) with patches of various configurations. MATERIAL AND METHODS: The method was demonstrated on a reconstructed model of intact vessel based on preoperative CT of the affected vessel in a certain patient. Blood flow is modeled by computational fluid dynamics using Doppler ultrasound data. Risk factors were assessed considering hemodynamic parameters of vascular wall associated with WSS. RESULTS: We studied hemodynamic results of 10 virtual CEA with patches of various shapes on the example of a reconstructed intact artery in a particular patient. Patch implantation is aimed at prevention of carotid artery narrowing since simple suture without a patch can reduce circumference of the artery by 4-5 mm. This result adversely affects blood flow. On the other hand, too wide a patch creates aneurysm-like deformation of internal carotid artery bulb. It is not optimal due to a large recirculation zone. It was found that patch width approximately equal to 3 mm ensures an optimal hemodynamic result. Deviations from this median value, both upward and downward, impair hemodynamics while the absence of a patch results the worst result. CONCLUSION: The proposed computer modeling technique is able to provide a personalized patch selection for CEA with low risk of restenosis in long-term follow-up period.

Mathematical simulation of p53-Mdm2 protein biological system regulation.

Digital simulation of disorders in the p53 and Mdm2 protein system, involved in repair of DNA defects and in many vital processes, including tumor formation, neurodegeneration, and aging, was carried out on the base of functional nonlinear octoparametric mathematical model. Stress situations were studied, associated with emergence of imbalance in p53 and Mdm2 generation and degradation rates and with disorders in the mechanism of protein interactions, regulated within the framework of the suggested model via dissociation constants. Variants of the analyzed disorders compensation by repeated stress for the system parameters were studied numerically.

Mathematical modeling of functioning of the p53-Mdm2 protein system.

Mathematical simulation of the time course of p53 and Mdm2 protein concentrations during their interactions was carried out. The system states corresponding to threatened uncontrolled apoptotic cell death accelerating aging processes and to situation with hypersuppression of p53-dependent apoptosis fraught with high risk of cancer were modeled. New data indicate the possibility of description (within the framework of mathematical model used in the study) of the p53 and Mdm2 proteins feedback mechanism, which could guarantee adequate reaction to serious DNA damage.

Using numerical modelling to evaluate Tsunami hazard near the Kuril Island

A sequence of computer experiments is used to study questions concerning the tsunami problem as a quantitative estimate of tsunami danger, detailed geographical tsunami classificaion, determination of the parameters of critical tsunami waves, and the conditions of their development.We call a wave critical' if its impact on the coast is most hazardous. The major singularities of the wavefiel arise in the zones of the deep-water straits. The distribution of the amplification factors is determined by both the global parameters of the wavefields and the local properties of individual harbours. The results obtained for a particular harbour in the northern part of Simushir Island, formed the basis for the quantitative estimate of tsunami danger for this area (AU)