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The flow profiles was first derived by John R. Womersley (1907–1958) in his work with blood flow in arteries. [1] The cardiovascular system of chordate animals is a very good example where pulsatile flow is found, but pulsatile flow is also observed in engines and hydraulic systems, as a result of rotating mechanisms pumping the fluid.
It is a dimensionless expression of the pulsatile flow frequency in relation to viscous effects. It is named after John R. Womersley (1907–1958) for his work with blood flow in arteries. [1] The Womersley number is important in keeping dynamic similarity when scaling an experiment. An example of this is scaling up the vascular system for ...
Endothelial activation is a proinflammatory and procoagulant state of the endothelial cells lining the lumen of blood vessels. [1] It is most characterized by an increase in interactions with white blood cells (leukocytes), and it is associated with the early states of atherosclerosis and sepsis , among others. [ 2 ]
The theory of the velocity of the transmission of the pulse through the circulation dates back to 1808 with the work of Thomas Young. [9] The relationship between pulse wave velocity (PWV) and arterial wall stiffness can be derived from Newton's second law of motion (=) applied to a small fluid element, where the force on the element equals the product of density (the mass per unit volume ...
For this reason, the blood flow velocity is the fastest in the middle of the vessel and slowest at the vessel wall. In most cases, the mean velocity is used. [18] There are many ways to measure blood flow velocity, like videocapillary microscoping with frame-to-frame analysis, or laser Doppler anemometry. [19]
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Pulsatile secretion is a biochemical phenomenon observed in a wide variety of cell and tissue types, in which chemical products are secreted in a regular temporal pattern. The most common cellular products observed to be released in this manner are intercellular signaling molecules such as hormones or neurotransmitters .
EXCOR is a paracorporeal, pulsatile flow VAD. [10] The device provides left ventricular, right ventricular or biventricular assistance. [11] The EXCOR system includes paracorporeal, pneumatically-driven polyurethane blood pumps. Each pump consists of a blood chamber and an air chamber which are separated by a multilayer flexible membrane. [12]