scholarly journals A coupled biventricular finite element and lumped-parameter circulatory system model of heart failure

2013 ◽  
Vol 16 (8) ◽  
pp. 807-818 ◽  
Author(s):  
Jonathan F. Wenk ◽  
Liang Ge ◽  
Zhihong Zhang ◽  
Mehrdad Soleimani ◽  
D. Dean Potter ◽  
...  
Keyword(s):  
Heart Failure ◽  
Finite Element ◽  
Circulatory System ◽  
System Model ◽  
Lumped Parameter

scholarly journals Osteoprotegerin and RANKL-RANK-OPG-TRAIL signalling axis in heart failure and other cardiovascular diseases

2021 ◽  
Author(s):  
Mieczysław Dutka ◽  
Rafał Bobiński ◽  
Wojciech Wojakowski ◽  
Tomasz Francuz ◽  
Celina Pająk ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Heart Failure ◽  
Cardiovascular Diseases ◽  
Vascular Endothelial Cells ◽  
Circulatory System ◽  
Prognostic Indicator ◽  
High Plasma ◽  
Mechanisms Of Action ◽  
Left Ventricular ◽  
High Ratio

AbstractOsteoprotegerin (OPG) is a glycoprotein involved in the regulation of bone remodelling. OPG regulates osteoclast activity by blocking the interaction between the receptor activator of nuclear factor kappa B (RANK) and its ligand (RANKL). More and more studies confirm the relationship between OPG and cardiovascular diseases. Numerous studies have confirmed that a high plasma concentration of OPG and a low concentration of tumour necrosis factor–related apoptosis inducing ligand (TRAIL) together with a high OPG/TRAIL ratio are predictors of poor prognosis in patients with myocardial infarction. A high plasma OPG concentration and a high ratio of OPG/TRAIL in the acute myocardial infarction are a prognostic indicator of adverse left ventricular remodelling and of the development of heart failure. Ever more data indicates the participation of OPG in the regulation of the function of vascular endothelial cells and the initiation of the atherosclerotic process in the arteries. Additionally, it has been shown that TRAIL has a protective effect on blood vessels and exerts an anti-atherosclerotic effect. The mechanisms of action of both OPG and TRAIL within the cells of the vascular wall are complex and remain largely unclear. However, these mechanisms of action as well as their interaction in the local vascular environment are of great interest to researchers. This article presents the current state of knowledge on the mechanisms of action of OPG and TRAIL in the circulatory system and their role in cardiovascular diseases. Understanding these mechanisms may allow their use as a therapeutic target in cardiovascular diseases in the future.

An Efficient Preconditioner for Linear System Solution in Multi-Domain Modeling of the Circulatory System

2013 ◽  
Author(s):  
Mahdi Esmaily Moghadam ◽  
Yuri Bazilevs ◽  
Tain-Yen Hsia ◽  
Alison Marsden
Keyword(s):  
Strong Coupling ◽  
Large Scale ◽  
Computational Cost ◽  
Circulatory System ◽  
Flow Simulation ◽  
Global Dynamics ◽  
Domain Modeling ◽  
Computationally Efficient ◽  
Lumped Parameter ◽  
System Solution

A closed-loop lumped parameter network (LPN) coupled to a 3D domain is a powerful tool that can be used to model the global dynamics of the circulatory system. Coupling a 0D LPN to a 3D CFD domain is a numerically challenging problem, often associated with instabilities, extra computational cost, and loss of modularity. A computationally efficient finite element framework has been recently proposed that achieves numerical stability without sacrificing modularity [1]. This type of coupling introduces new challenges in the linear algebraic equation solver (LS), producing an strong coupling between flow and pressure that leads to an ill-conditioned tangent matrix. In this paper we exploit this strong coupling to obtain a novel and efficient algorithm for the linear solver (LS). We illustrate the efficiency of this method on several large-scale cardiovascular blood flow simulation problems.

Performance of a Stirling Engine Regenerator Having Finite Mass

1986 ◽  
Vol 108 (4) ◽  
pp. 669-673 ◽  
Author(s):  
J. D. Jones
Keyword(s):  
Finite Element ◽  
Pressure Variation ◽  
Stirling Engine ◽  
System Model ◽  
Finite Mass ◽  
Element System ◽  
The Matrix ◽  
Cyclic Variations ◽  
Good Agreement ◽  
Engine Power

The performance of a Stirling engine regenerator subjected to sinusoidal mass flow rate and pressure variation is analyzed. It is shown that cyclic variations in the temperature of the matrix due to its finite mass lead to an increase in the apparent regenerator effectiveness, but a decrease in engine power. Approximate closed-form expressions for both of these effects are deduced. The results of this analysis are compared with the predictions of a finite-element system model, and good agreement is found.

Development of an Engine System Model for Predicting Structural Vibration

1995 ◽  
Author(s):  
S. H. Sung ◽  
D. J. Nefske
Keyword(s):  
Finite Element ◽  
Narrow Band ◽  
Vibration Response ◽  
System Model ◽  
Structural Vibration ◽  
Octave Band ◽  
Engine System ◽  
Excitation Frequencies ◽  
Engine Components ◽  
Structural Mass

Abstract A finite-element based engine system model is developed for predicting the structural vibration of the engine. The engine system model combines modal models of the major bolted-together sub-structures of the engine, with non-structural mass models of the remaining engine components added to bring the inertial properties to those of the running engine. The model is developed and experimentally evaluated with impact and shaker excitation tests. Comparisons are made of the predicted and measured vibration response for various partially assembled engine configurations, as well as for the fully assembled engine. The comparisons illustrate the accuracy of the model in predicting the narrow-band and one-third octave-band vibration response for excitation frequencies up to 2 kHz.

scholarly journals Efficient finite element hyperelasticity solver for blood vessel simulations

2020 ◽  
Vol 14 ◽  
pp. 174830262093101
Author(s):  
Xinhong Wang ◽  
Zhengzheng Yan ◽  
Yi Jiang ◽  
Rongliang Chen
Keyword(s):  
Finite Element ◽  
Blood Vessel ◽  
Blood Vessels ◽  
High Performance ◽  
Soft Tissues ◽  
Circulatory System ◽  
Numerical Algorithms ◽  
External Pressure ◽  
Patient Specific ◽  
Schwarz Method

The blood vessels play a key role in the human circulatory system. As a tremendous amount of efforts have been devoted to develop mathematical models for investigating the elastic behaviors of human blood vessels, high performance numerical algorithms aiming at solving these models have attracted attention. In this work, we present an efficient finite element solver for an elastodynamic model which is commonly used for simulating soft tissues under external pressure loadings. In particular, the elastic material is assumed to satisfy the Saint–Venant–Kirchhoff law, the governing equation is spatially discretized by a finite element method, and a fully implicit backward difference method is used for the temporal discretization. The resulting nonlinear system is then solved by a Newton–Krylov–Schwarz method. It is the first time to apply the Newton–Krylov–Schwarz method to the Saint–Venant–Kirchhoff model for a patient-specific blood vessel. Numerical tests verify the efficiency of the proposed method and demonstrate its capability for bioengineering applications.

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