• fluid
  • A fluid is circulated through the tubing at a constant flow rate. (google.co.uk)
  • 128-349) ABSTRACT OF THE DISCLOSURE A catheter having a valve for controlling the flow of fluid therethrough comprising an elongated tube of flexible material having a closed end, an open end and a fluid entrance hole in the wall thereof adjacent the closed end. (google.com.au)
  • Since a continuous drainage is usually not necessary, it would be desirable to have a catheter which includes means operable by the user to control the flow of fluid therethrough. (google.com.au)
  • It is another object of the present invention to provide a catheter having means operable by the user for controlling the flow of fluid therethrough. (google.com.au)
  • It is a further object of the present invention to provide a catheter having a valve therein operable by the user to permit and stop the flow of fluid therethrough. (google.com.au)
  • Once fluid flow begins, biomechanical and hemodynamic inputs are applied to the system set up by vasculogenesis, and the active remodelling process can begin. (wikipedia.org)
  • Aqueductal stenosis is a narrowing of the aqueduct of Sylvius which blocks the flow of cerebrospinal fluid (CSF) in the ventricular system. (wikipedia.org)
  • transient
  • Taken together, our results suggest that Alk1 plays a role in transducing hemodynamic forces into a biochemical signal required to limit nascent vessel caliber, and support a novel two-step model for HHT-associated AVM development in which pathological arterial enlargement and consequent altered blood flow precipitate a flow-dependent adaptive response involving retention of normally transient arteriovenous connections, thereby generating AVMs. (biologists.org)
  • Transient flow reversal occurred almost everywhere in the branch, and a transient separated region was found corresponding to the low-shear region in the daughter vessel. (ahajournals.org)
  • shear stress
  • High local SD at near-wall measurements suggests that further refinement is required before proceeding to in vivo quantification studies of wall shear stress in complex flow environments. (deepdyve.com)
  • velocity profiles
  • This relationship between genetics and environment is not clearly understood, but researchers are attempting to clarify it by combining reliable genetic techniques, such as genetically-ablated model organisms and tissues, with new technologies developed to measure and track flow patterns, velocity profiles, and pressure fluctuations in vivo. (wikipedia.org)
  • resistance
  • When the internal pressure of the tubing is greater than the external pressure, the bubble expands and there is no increase in the flow resistance of the system. (google.co.uk)
  • When the pressure on the outside exceeds the normal system operating pressure, the thin wall section or bubble contacts, resistance to flow increases, and the system pressure increases. (google.co.uk)
  • stenosis
  • As a result of a number of disease processes, both acquired and congenital, any one of the four heart valves may malfunction and result in either stenosis (impeded forward flow) and/or backward flow (regurgitation). (wikipedia.org)
  • tissue
  • Given these findings, the surgical team recommended an attempt at distal revascularization of the digits to prevent further tissue loss. (eplasty.com)
  • This blockage causes ventricle volume to increase because the CSF cannot flow out of the ventricles and cannot be effectively absorbed by the surrounding tissue of the ventricles. (wikipedia.org)
  • Tissue heart valves, in contrast, do not require the use of anticoagulant drugs due to the improved blood flow dynamics resulting in less red cell damage and hence less clot formation. (wikipedia.org)
  • anterior
  • After controlling for age, pulse, blood pressure, anterior MI location, epicardial flow, and creatine kinase, pulsatile flow remained associated with an increased risk of death/MI (odds ratio 3.1, p = 0.006). (onlinejacc.org)
  • calculation
  • The calculation and modeling of vascular input impedance are based on the assumption that pressure and flow are linearly related in the frequency domain. (ahajournals.org)
  • The calculation of vascular impedance by Fourier methods and Windkessel-type lumped parameter models is based on the assumption that pressure and flow are linearly related in the frequency domain. (ahajournals.org)
  • Independence of harmonics ensures a unique relationship between corresponding harmonics of pressure and flow and, therefore, justifies the calculation of vascular impedance and hydraulic energy. (ahajournals.org)
  • pressure
  • When the compartmental pressure rises above normal, (pressure of approximately 0 to 30mm Hg) functional capillary flow through the capillary beds stops. (google.co.uk)
  • The return of a pink color after pressure application to the distal parts was believed to indicate a satisfactory blood supply. (google.co.uk)
  • Therefore, we investigated the linearity of pulsatile pressure-flow relations in vivo with acute alterations in cycle length. (ahajournals.org)
  • The quantitative analysis of pulsatile pressure-flow relationships provides insight into the structure and regulation of the cardiovascular system. (ahajournals.org)
  • The direct proof of linearity was obtained in vitro by driving an isolated vascular system with a pure sinusoidal flow input and then determining pulsatile pressure-flow relationships with the use of Fourier analysis. (ahajournals.org)
  • To compensate for the partial blockage and increase the CSF flow to normal rates, the pressure in the third ventricle is increased thereby also increasing the velocity of the CSF. (wikipedia.org)
  • When blood pressure in the chamber of the heart exceeds that of the pressure on the outside of the chamber the ball is pushed against the cage and allows blood to flow. (wikipedia.org)
  • development
  • To understand the etiology of AVMs and the role of blood flow in their development, we analyzed AVM development in zebrafish embryos harboring a mutation in activin receptor-like kinase I ( alk1 ), which encodes a TGFβ family type I receptor implicated in the human vascular disorder hereditary hemorrhagic telangiectasia type 2 (HHT2). (biologists.org)
  • Pulsatile energy may be a potential promoter of vascular development. (ahajournals.org)
  • The shear profiles and the calculated separated region were influenced to some degree by the extent of flow development at the branch inlet and markedly by the branch area ratio. (ahajournals.org)
  • legs
  • This severe lack of blood flow can lead to painful legs while walking or at rest and can result in foot sores, ulcers, gangrene, and even amputation. (clinicaltrials.gov)
  • arterial
  • Numerical simulations of pulsatile blood flow through a symmetrical branch modeling the aortic bifurcation were carried out to assess several hemodynamic theories of atherogenesis by comparing the distribution of hemodynamic variables with that of early lesions in arterial branches. (ahajournals.org)
  • functional
  • Similar to other neuroimaging techniques such as functional magnetic resonance imaging (fMRI) and positron emission tomography (PET), fTCD is based on a close coupling between regional cerebral blood flow changes and neural activation. (wikipedia.org)
  • Natural heart valves are evolved to forms that perform the functional requirement of inducing unidirectional blood flow through the valve structure from one chamber of the heart to another. (wikipedia.org)
  • release
  • For example, discharge from human settlement including runoff and water flowing out of wastewater treatment plants release a large amount of xenoestrogens into streams, which lead to immense alterations in aquatic life. (wikipedia.org)
  • lower
  • If successful, this treatment could improve blood flow to the lower limb, reduce pain, and reduce the frequency of limb amputations. (clinicaltrials.gov)
  • Both of these deformations disrupt the laminar flow of CSF through the ventricular system, causing the force by the aqueduct on its surroundings to be lower than the compressive force being applied to the aqueduct. (wikipedia.org)
  • values
  • the highest values occurred at the convex corner on the outer wall of the branch and in the neighborhood of the flow divider tip, and the lowest shears were experienced by the outer wall of the daughter vessel a short distance distal to the corner. (ahajournals.org)
  • He used diluted plasma or serum as the perfusate and pointed out the necessity for low perfusate pressures to prevent kidney swelling, but admitted that the optimum values for such variables as perfusate temperature, Po2, and flow, remained unknown. (wikipedia.org)
  • vivo
  • Johnston, Clifton 2014-09-16 00:00:00 Echo particle image velocimetry (Echo PIV) presents itself as an attractive in vivo flow quantification technique to traditional approaches. (deepdyve.com)
  • greater
  • This greater compressive force could effectively stop the flow of CSF if the aqueduct closes due to the force. (wikipedia.org)