Evaluation of the impact of arterial wall viscosity in pressure morphology by means of a simplified 1D model

2016 ◽  
Author(s):  
F. Gabaldon Castillo ◽  
L. J. Cymberknop ◽  
M. R. Alfonso ◽  
M. Martinez Sartore ◽  
R. L. Armentano
Keyword(s):  
Arterial Wall ◽  
1D Model ◽  
The Impact ◽  
Arterial Wall Viscosity

Abstract 1165: Impact of Gender on Serial Atherosclerotic Changes in Response to Established Medical Therapies

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Srinivasa R Kalidindi ◽  
Amy Hsu ◽  
Keon-Woong Moon ◽  
E. Murat Tuzcu ◽  
Steven E Nissen ◽  
...  
Keyword(s):  
Coronary Artery ◽  
Arterial Wall ◽  
Elastic Membrane ◽  
Single Coronary Artery ◽  
Plaque Progression ◽  
Ultrasound Evaluation ◽  
External Elastic Membrane ◽  
Remodeling Index ◽  
Medical Therapies ◽  
The Impact

Background: While the importance of coronary artery disease in females has become increasingly recognized, little is known regarding the impact of gender with regard to changes in arterial wall dimensions with progression and regression of atherosclerosis. This study investigated the remodeling response of the artery wall accompanying changes in atheroma burden in response to use of medical therapies, stratified according to gender. Methods: 1533 patients (27.5% female) underwent serial intravascular ultrasound evaluation of a single coronary artery in the context of clinical trials that assess the impact of medical therapies on plaque progression. The relationship between gender and remodeling of the arterial wall at baseline and its serial change in association with plaque progression and regression were studied. Results: Females were older (59 v 57 years, p<0.01), had a higher body mass index (31.5 v 29.5 kg/m 2 , p<0.01), were more likely to have hypertension (86 v 71.5%, p<0.01) and metabolic syndrome (57 v 49%, p<0.01) and less likely to have a history of smoking (57.5 v 73.5%, p=0.01) and myocardial infarction (27.5 v 35.5%, p<0.01). After adjusting for body surface area, females demonstrated a trend towards smaller external elastic membrane (EEM) (226.3 v 234.3 mm 3 , p=0.09) and larger lumen (143.7 v 137.7 mm 3 , p=0.01) volumes. The remodeling index at the most diseased site did not differ between genders (0.95 v 0.95, p=0.95). No differences were observed between genders with regard to changes in EEM (−5.6 v −6.2 mm 3 , p=0.29) and lumen (−4.9 v −4.5 mm 3 , p=0.82) volumes and remodeling index (−0.02 v −0.03, p=0.43) in response to use of medical therapies. Similarly, there were no differences between genders with regard to the percentage of patients undergoing expansion (34.7 v 35.5%, p=0.86) or contraction (20.4 v 21.8%, p=0.69) of lumen volume in association with regression of atherosclerotic plaque. Conclusion: A similar pattern of remodeling of the arterial wall was observed between genders in association with serial changes in atheroscle-rotic plaque. This further highlights our understanding of the pathological interactions between atherosclerosis and the arterial wall in females.

scholarly journals Effect of Gate Selection on the Non-Cohesive Sedimentation in Irrigation Schemes

Water ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2765
Author(s):  
Shaimaa Theol ◽  
Bert Jagers ◽  
Jigyasha Rai Yangkhurung ◽  
F.X. Suryadi ◽  
Charlotte de Fraiture
Keyword(s):  
Cohesive Sediment ◽  
Sediment Deposition ◽  
Hydraulic Parameters ◽  
Crop Water ◽  
Gate Operation ◽  
Control Structures ◽  
Sediment Removal ◽  
1D Model ◽  
The Impact ◽  
Selection Of

In order to cover the crop water requirements, flow control structures such as gates and weirs are used to transfer the desired amount of water from the canals to the field canals. This paper examines the impact of gate operation and the selection of gates on the deposition of non-cohesive sediment. The Delft3D model is used to simulate the effects of different scenarios regarding gate operation and the location of the gate that is opened. The model results showed that the gate selection affects not only hydraulic parameters but also morphological parameters. It was found that opening the gates closer to the offtake resulted in less sediment deposition at the entrance of the branch canal when compared to opening the gates further away. Gate selection can be used as a tool in sediment management. By alternating the opening of different gates sediments that are already deposited after opening one gate can be eroded when another gate is operated, thus minimizing the additional cost of sediment removal. The use of Delft3D proved beneficial as the selection of different gates leads to asymmetric sediment deposition patterns which would be missed when using a 1D model.

A New 3D Reconstruction Method for Human Coronary Bifurcations for Shear Stress Computations

2012 ◽  
Author(s):  
Frank Gijsen ◽  
Hans Schuurbiers ◽  
Michiel Schaap ◽  
Anton van der Steen ◽  
Jolanda Wentzel
Keyword(s):  
Shear Stress ◽  
Coronary Arteries ◽  
Arterial Wall ◽  
Plaque Formation ◽  
Atherosclerotic Plaques ◽  
Reconstruction Method ◽  
Human Coronary Artery ◽  
Multislice Computer Tomography ◽  
Stress Influences ◽  
The Impact

Atherosclerosis is characterized by lipid accumulation in the arterial wall, followed by an inflammatory response. Plaque formation is generally observed near bifurcations in coronary arteries. The composition of atherosclerotic plaques depends on the location, and it was hypothesized that blood flow induced shear stress influences plaque composition2. To study the impact of shear stress on atherosclerotic disease in human coronary arteries, we developed a technique that enables us to generate 3D lumen reconstruction based on multislice computer tomography (MSCT) and intravascular ultrasound (IVUS).We describe two approaches to generate 3D reconstructions of human coronary artery bifurcations and apply them to coronary segments with bifurcations. We will evaluate the effect on shear stress distribution and its relationship to wall thickness.

scholarly journals The impact of multiple operations on the importance of arterial wall cultures

1987 ◽  
Vol 5 (1) ◽  
pp. 160-169 ◽  
Author(s):  
J.R. Durham ◽  
J.M. Malone ◽  
V.M. Bernhard
Keyword(s):  
Arterial Wall ◽  
The Impact

Arterial Wall Viscosity Is Associated With Cardiorespiratory Fitness Independently Of Aging

2014 ◽  
Vol 46 ◽  
pp. 537
Author(s):  
Hiroshi Kawano ◽  
Kenta Yamamoto ◽  
Yuko Gando ◽  
Michiya Tanimoto ◽  
Haruka Murakami ◽  
...  
Keyword(s):  
Cardiorespiratory Fitness ◽  
Arterial Wall ◽  
Arterial Wall Viscosity

Effects of Manufacturing Noise on Microturbine Centrifugal Impeller Performance

2012 ◽  
Author(s):  
A. Javed ◽  
R. Pecnik ◽  
M. Olivero ◽  
J. P. van Buijtenen
Keyword(s):  
Performance Analysis ◽  
Three Dimensional ◽  
Geometric Parameters ◽  
Tip Clearance ◽  
Centrifugal Impeller ◽  
Analysis Tool ◽  
Modeling Tools ◽  
Output Performance ◽  
1D Model ◽  
The Impact

This paper presents a study on a small centrifugal impeller for microturbine application from a manufacturing perspective. The aim is to analyze the impact of geometric deviations on part performance using adequate performance modeling tools and statistical methods. A one-dimensional (1D) performance analysis tool has been developed in-house derived from the meanline and two-zone modeling methods. The 1D model has proved to be a simple and computationally inexpensive tool for having a quick performance analysis of the impeller using basic geometric information extracted from part drawings. For the sensitivity analysis, a total of eight input geometric parameters including radii, tip-clearance and blade angles have been varied individually within specific limits in the 1D tool for classifying their influence on the output performance. Since the 1D model is a simplified version of a much complex three-dimensional (3D) model, a commercial computational fluid dynamics (CFD) tool has been used to provide a comparison with the 1D model and scrutinize the effects of such deviations on the fluid behavior inside the impeller passage at a detailed level. For uncertainty quantification, Monte Carlo simulation has been performed using the 1D model to assess the variability of overall impeller output performance to simultaneous random deviations in the input geometric parameters. The study is useful to evaluate the possibility of designing gas turbine parts for manufacturability and superior production cost-effectiveness.

scholarly journals Imaging-Based Biomarkers: Characterization of Post-Kawasaki Vasculitis in Infants and Hypertension Phenotype in Rat Model

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Roch Listz Maurice ◽  
Nagib Dahdah ◽  
Johanne Tremblay
Keyword(s):  
Mechanical Properties ◽  
Arterial Wall ◽  
Turning Point ◽  
Aortic Wall ◽  
Brown Norway ◽  
Carotid Stiffness ◽  
Old Rats ◽  
The Impact

Background. Investigating the mechanical properties of the arteries is essential in cardiovascular diseases. Recent imaging modalities allow mapping mechanical properties within the arterial wall.Aims. We report the potential ofimaging-based biomarker(ImBioMark) to investigate the effect of aging on the rat. We also present preliminary data with ImBioMark characterizing vascular sequelae of Kawasaki disease (KD) in young humans.Methods. We investigatedin vivothe effect of aging on male Brown Norway (BN) rats' (n=5) carotid stiffness. In a second experiment, the impact of KD on the ascending aorta (AA) was examined in KD children (n=2) aged 13 ± 1.41 years old compared to KD-free children (n=5) aged 13.13 ± 0.18 years old.Results. The stiffness of BN's carotid artery was three times stiffer in the old rats, with a turning point at 40 weeks old (P=0.001). KD had a very significant impact on the AA stiffness with strain estimates of 2.39 ± 0.51% versus 4.24 ± 0.65% in controls (P<0.001).Conclusion. ImBioMark phenotypes hypertension in rat models noninvasivelyin vivowithout resorting to euthanasia. Quantifying aortic wall remodeling is also feasible in humans. Future investigations target human cardiovascular disease.

scholarly journals Dynamic Force on an Elbow Caused by a Traveling Liquid Slug

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Darcy Q. Hou ◽  
Arris S. Tijsseling ◽  
Zafer Bozkus
Keyword(s):  
Experimental Data ◽  
Impact Force ◽  
Initial Conditions ◽  
Flow Direction ◽  
Dynamic Force ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
1D Model ◽  
High Reynolds ◽  
The Impact

The impact force on an elbow induced by traveling isolated liquid slugs in a horizontal pipeline is studied. A literature review reveals that the force on the elbow is mainly due to momentum transfer in changing the fluid flow direction around the elbow. Therefore, to accurately calculate the magnitude and duration of the impact force, the slug arrival velocity at the elbow needs to be well predicted. The hydrodynamic behavior of the slug passing through the elbow needs to be properly modeled too. A combination of 1D and 2D models is used in this paper to analyze this problem. The 1D model is used to predict the slug motion in the horizontal pipeline. With the obtained slug arrival velocity, slug length, and driving air pressure as initial conditions, the 2D Euler equations are solved by the smoothed particle hydrodynamics (SPH) method to analyze the slug dynamics at the elbow. The 2D SPH solution matches experimental data and clearly demonstrates the occurrence of flow separation at the elbow, which is a typical effect of high Reynolds flows. Using the obtained flow contraction coefficient, an improved 1D model with nonlinear elbow resistance is proposed and solved by SPH. The 1D SPH results show the best fit with experimental data obtained so far.

P10 LOSS OF ENDOTHELIUM-DEPENDENT REGULATION OF ARTERIAL WALL VISCOSITY IN ESSENTIAL HYPERTENSION

2017 ◽  
Vol 20 (C) ◽  
pp. 64
Author(s):  
Frederic Roca ◽  
Jeremy Bellien ◽  
Michele Lacob ◽  
Robinson Joannides
Keyword(s):  
Essential Hypertension ◽  
Arterial Wall ◽  
Arterial Wall Viscosity
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