شبيه سازي پديده پلاكت خون به روش Dissipative particle Dynamics

چكيده انگليسي :

Investigating the Effect of Blood Flow Velocity on Platelet Thrombi Formation using Dissipative Particle Dynamics Method Abbas Asadpanah a asadpanah@me iut ac ir 16st March 2010 Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Ahmad Reza Pishevar apishe@cc iut ac ir Mohammad Said Saidi mssaidi@sharif ir Abstract Platelet aggregation a vital phenomenon which occurs hundreds of times daily in blood vessels is themain cause of closing minute ruptures This paper seeks to simulate platelet aggregation with a uniqueparticle base method as to monitor the impact of blood velocity during thrombi formation Related literaturesapplied various computational methods and determined that the rate of growth of aggregated platelet dependsmarkedly on blood flow velocity Dissipative Particle Dynamics DPD method is potentially effective in simulating mesoscalehydrodynamics This is an advantageous idea behind this method which enables it to run with lowercomputational cost in comparison with other methods such as Molecular Dynamics MD Therefore in thiswork we investigate the dependence of the adhered platelets growth rate to the blood flow velocity usingDPD method In our model the boundary conditions in a Poiseuille flow were considered periodic along with the flowdirection which is initially free of platelets The platelets are modeled as rigid spheres by grouping the DPDparticles The modeled platelets can be in three different biological states passive triggered and activated Inpassive state platelets are not adhesive this is a normal state of the platelets in blood If a passive plateletinteracts with an injured wall or an activated platelet it becomes triggered and after the activation delay time a time interval required for a passive platelet to go through the activation process and develop its ability toadhere it is activated and becomes adhesive This biological interaction was taken into account when tworepulsive and two other attraction forces were applied in addition to DPD conventional forces The activationdelay time was confined in a specified range and was chosen in a random manner uniformly We found that the exponential aggregation growth rate initially rose with the blood flow rate reaching toa peak and for higher flow rates it would then fall This was ascribed to the effect of the activation delaytime At higher flow rates more activated platelets escaped from the primary thrombus We detected an early up to about 3 seconds phase of rapid growth of the thrombus a result which has never been discernedexperimentally due to the difficulty of seeing a distinctly mural grouping of so few platelets Distribution ofsizes of simulated clots in a number of coagulated platelets obtained after 10 s for different blood flowvelocities This distribution is very similar to the one observed by Begent Born the simulation resultsquantitatively agree with the experimental data meaning that simulation and experimental data are of thesame order of magnitude The simulations also demonstrate that growth of the thrombus is strongly affectedby two opposing factors the rate at which the platelets are supplied by the blood flow to the thrombus andthe intensity of shear force that prevents platelets from adhering to the thrombus When the blood flow rate is

اسدپناه، عباس

شبيه سازي پديده پلاكت خون به روش Dissipative particle Dynamics

تجمع پلاكتها , روش DPD , ضريب نرخ رشد