tailieunhanh - Báo cáo y học: "Pulsatile blood flow, shear force, energy dissipation and Murray's Law"

Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học quốc tế cung cấp cho các bạn kiến thức về ngành y đề tài:Pulsatile blood flow, shear force, energy dissipation and Murray's Law | Theoretical Biology and Medical Modelling BioMed Central Research Open Access Pulsatile blood flow shear force energy dissipation and Murray s Law Page R Painter 1 Patrik Edén2 and Hans-Uno Bengtsson2 Address 1Office of Environmental Health Hazard Assessment California Environmental Protection Agency P. O. Box 4010 Sacramento California 95812 USA and 2Department of Theoretical Physics Lund University S-223 62 Soelvegatan 14A Lund Sweden Email Page R Painter - ppainter@ Patrik Edén - patrik@ Hans-Uno Bengtsson - Corresponding author Published 21 August 2006 Received 14 March 2006 Theoretical Biology and Medical Modelling 2006 3 3 I doi 1742-4682-3-31 Accepted 21 August 2006 This article is available from http content 3 1 31 2006 Painter et al licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License http licenses by which permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited. Abstract Background Murray s Law states that when a parent blood vessel branches into daughter vessels the cube of the radius of the parent vessel is equal to the sum of the cubes of the radii of daughter blood vessels. Murray derived this law by defining a cost function that is the sum of the energy cost of the blood in a vessel and the energy cost of pumping blood through the vessel. The cost is minimized when vessel radii are consistent with Murray s Law. This law has also been derived from the hypothesis that the shear force of moving blood on the inner walls of vessels is constant throughout the vascular system. However this derivation like Murray s earlier derivation is based on the assumption of constant blood flow. Methods To determine the implications of the constant shear force hypothesis and to extend Murray s energy cost minimization to the pulsatile .