Georgy Guria - Academia.edu (original) (raw)

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Università degli Studi di Firenze (University of Florence)

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Papers by Georgy Guria

Journal of Medical Devices, 2010

PLOS ONE, 2015

Increased shear stress such as observed at local stenosis may cause drastic changes in the permea... more Increased shear stress such as observed at local stenosis may cause drastic changes in the permeability of the vessel wall to procoagulants and thus initiate intravascular blood coagulation. In this paper we suggest a mathematical model to investigate how shear stress-induced permeability influences the thrombogenic potential of atherosclerotic plaques. Numerical analysis of the model reveals the existence of two hydrodynamic thresholds for activation of blood coagulation in the system and unveils typical scenarios of thrombus formation. The dependence of blood coagulation development on the intensity of blood flow, as well as on geometrical parameters of atherosclerotic plaque is described. Relevant parametric diagrams are drawn. The results suggest a previously unrecognized role of relatively small plaques (resulting in less than 50% of the lumen area reduction) in atherothrombosis and have important implications for the existing stenting guidelines.

Московский физико-технический институт (государственный университет) 141700, г. Долгопрудный Моск... more Московский физико-технический институт (государственный университет) 141700, г. Долгопрудный Московской обл., Институтский пер., 9, МФТИ Предложена модель роста оторвавшегося от стенки сосуда тромба в пристеночном потоке, учитывающая не только влияние гидродинамических потоков на протекающие в системе химические реакции, но и обратное влияние растущего тромба на картину течения. При этом использовались аналитические решения для определения поля скоростей жидкости вблизи тромба. Проведенное численное исследование модели показало, что гидродинамические потоки могут оказать существенное влияние на процессы тромбообразования. В частности, их наличие может приводить к разрушению цилиндрически-симметричных концентрационных фронтов реагентов и образованию так называемых химических пятен. В результате их эволюции образуются тромбы сложной структуры. Показано, что процесс тромбообразования зависит от соотношения характерных значений скорости крови в сосуде и скоростей химических реакций.

Zeitschrift für Physik B Condensed Matter, 1982

ABSTRACT

General physiology and biophysics, 1997

The mechanisms of autowaves propagation through local non-homogeneities in active media relevant ... more The mechanisms of autowaves propagation through local non-homogeneities in active media relevant to diverse class of physiological systems were studied by means of a computer simulation. The model proposed by Zel'dovich and Frank-Kamenetsky and that of FitzHugh-Nagumo were used for studying autowave tunneling, which in a broad sense implies underbarrier passing. It was shown that for every fixed parameter value corresponding to the degree of non-excitability of local area a critical value for non-excitable zone latitude exists. An autowave overcomes the barrier and continues to propagate when the value of zone latitude is less than critical. Critical conditions for origination of a source of periodical sequence of impulses in excitable medium were found. The source properties, as shown, can be modified by regulation of size of a non-excitable zone and a zone of higher excitability. In particular, the conditions when spatial irregularity behaves as a source of unidirectional and/...