An in-vitro (hydrodynamic) model of the circulatory system was developed. The model consisted of a pump, compliant tubing, and valves for resistance. The model is used to simulate aortic pressure and flow. These parameters were measured using a Konigsburg Pressure transducer and a Triton ART2 flow probe. In addition, venous pressure and flow were measured on the downstream side of the resistance. The system has a known compliance and resistance. Steady and pulsatile flow tests were conducted to determine the resistance of the model. A static compliance test was used to determine the compliance of the system. The aortic pressure and flow obtained from the hydrodynamic model will be used to test the accuracy of parameter estimation models such as the 2-element and 4-element Windkessel models and the 3-element Westkessel model. Verifying analytical models used in determining total peripheral resistance (TPR) and systemic arterial compliance (SAC) is important because it provides insight into hemodynamic parameters that indicate baroreceptor responsiveness to situations such as changes in gravitational acceleration.
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Acta Neurochir (Wien)
January 2025
Division of Neurosurgery, Beth Israel Deaconess Medical Center, Harvard Medical School, 110 Francis Street , Boston, MA, 02215, USA.
Background: Variability in long-term endovascular treatment outcomes for intracranial aneurysms has prompted questions regarding the effects of these treatments on aneurysm hemodynamics. Endovascular techniques disrupt aneurysmal blood flow and shear, but their influence on intra-aneurysmal pressure remains unclear. A better understanding of aneurysm pressure effects may aid in predicting outcomes and guiding treatment decisions.
View Article and Find Full Text PDFSci Rep
January 2025
School of Engineering, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
The use of winglet devices is an efficient technique for enhancing aerodynamic performance. This study investigates the effects of winglet cant angles on both the aerodynamics and aeroacoustics of a commercial wing, comparing them to other significant parameters using a parametric analysis. A Full Factorial Design method is employed to generate a matrix of experiments, facilitating a detailed exploration of flow physics, with lift-to-drag ratio (L/D) and the integral of Acoustic Power Level (APL) as the primary representatives of aerodynamic and acoustic performance, respectively.
View Article and Find Full Text PDFObjective: High-flow nasal cannula (HFNC) is generally considered to have fewer enteral feeding problems than nasal continuous positive airway pressure (NCPAP) or nasal intermittent positive-pressure ventilation (NIPPV). However, the effects of HFNC on the feeding outcomes in preterm infants are still controversial. The aim of this study was to assess the effect of HFNC on postnatal growth and feeding.
View Article and Find Full Text PDFMed Sci Sports Exerc
December 2024
Department of Rehabilitation Sciences, Ghent University, Ghent, BELGIUM.
Purpose: Eccentric calf training for Achilles tendinopathy shows variable success in athletes. Recent insights suggest a role for tendon fluid flow (exudation or redistribution) during exercise, which explains post-exercise reductions in thickness and increases in stiffness of the tendon. This fluid flow is thought to be beneficial as it may promote tendon remodeling, reduce intratendinous pressure, and alleviate pain.
View Article and Find Full Text PDFCardiol Rev
October 2024
From the Department of Medicine, New York Medical College, Valhalla, NY.
Resistant hypertension is defined as office blood pressure >140/90 mm Hg with a mean 24-hour ambulatory blood pressure of >130/80 mm Hg in patients who are compliant with 3 or more antihypertensive medications. Those who persistently fail pharmaceutical therapy may benefit from interventional treatment, such as renal denervation. Sympathetic nervous activity in the kidney is a known contributor to increased blood pressure because it results in efferent and afferent arteriole vasoconstriction, reduced renal blood flow, increased sodium and water reabsorption, and the release of renin.
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