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We test the robustness of a closed-loop treatment scheduling method to realistic HIV viral load measurement error. The purpose of the algorithm is to allow the accurate detection of an induced viral load minimum with a reduced number of samples. Therapy must be switched at or near the viral-load minimum to achieve optimal therapeutic benefit; therapeutic benefit decreases logarithmically with increased...
Bivalirudin is direct thrombin inhibitor used in patients with heparin-induced thrombocytopenia. A pharmacokinetic and — dynamic model that predicts the partial thromboplastin time (PTT) based on the past infusion rates of bivalirudin following dose adjustment would be useful to guide optimal therapy. In this retrospective study we randomized 132 patients to a derivation and a validation cohort, and...
Here, we propose a training data selection method using a Support Vector Machine (SVM) to predict the effects of anticancer drugs. Conventionally, SVM is used for distinguishing between several types of data. However, in the method proposed here, the SVM is used to distinguish areas with only one or two types of data. The proposed method treats training data selection as an optimization problem and...
An accurate knowledge of the spectral distribution emission is essential for precise dose calculations in radiotherapy treatment planning. Reconstruction of photon spectra emitted by medical accelerators from measured depth dose distributions in a water cube is an important tool for commissioning a Monte Carlo treatment planning system. However, the reconstruction problem is an inverse radiation transport...
Medical Decision Support Systems employ mathematical models to optimize therapy settings. The mathematical models are used to predict patient reactions towards alteration in the therapy regime. This prediction should not be limited to one detail but should feature a broad picture. A previously proposed framework is able to dynamically combine submodels of three model families (respiratory mechanics,...
We investigated numerical methods for predictors in a multiscale cardiovascular simulation model. The proposed method predicts initial approximations for the iterative convergence calculations of the strong coupling method using the smoothing spline to remove errors from values of past timesteps and using the linear and second-order extrapolation. The new coupling algorithm was used for coupling a...
In this study, we develop asynchronous probabilistic cell cycle models to quantitatively assess the effect of ionizing radiation on a human colon cancer cell line. We use both synchronous and asynchronous cell populations and follow treated cells for up to 2 cell cycle times. The model outputs quantify the changes in cell cycle dynamics following ionizing radiation treatment, principally in the duration...
The coagulation and fibrinolytic systems are complex, inter-connected biological systems with major physiological roles. The complex, nonlinear multi-point relationships between the molecular and cellular constituents of two systems render a comprehensive and simultaneous study of the system at the microscopic and macroscopic level a significant challenge. We have created an Agent Based Modeling and...
In medical research it is of great importance to be able to quickly obtain answers to inquiries about system response to different stimuli. Modeling the dynamics of biological regulatory networks is a promising approach to achieve this goal, but existing modeling approaches suffer from complexity issues and become inefficient with large networks. In order to improve the efficiency, we propose the...
Machine learning has been largely applied to analyze data in various domains, but it is still new to personalized medicine, especially dose individualization. In this paper, we focus on the prediction of drug concentrations using Support Vector Machines (S VM) and the analysis of the influence of each feature to the prediction results. Our study shows that SVM-based approaches achieve similar prediction...
A multiple dataset model fitting approach for improving parameter reliability in action potential modeling is presented. A robust generic cardiac ionic model employing membrane currents based on two-gate Hodgkin-Huxley kinetics is described. Its generic nature allows it to accurately reproduce action potential waveforms in heterogeneous cardiac tissue by optimizing parameters governing ion channel...
Striated muscle represents a unique type of actuator in that it depends on living tissue. Models of muscle have historically focused on the role of actuator, using properties that do not adapt over time. This paper extends the foundation of Hill-based muscle models by considering muscle as a tissue composed of well-mixed composite materials (at the level of fascicle), and identifies three specific...
In this paper we propose a new method based on finite element method for solving radiation boundary condition of heat equation inside the human eye and other applications. Using this method, we can solve heat equation inside human eye without need to model radiation boundary condition to a robin boundary condition. Using finite element method we can obtain a nonlinear equation, and finally we use...
Two types of boolean functions are considered, the locus function of n variables, and the interval function of ν = n − 1 variables. A 1–1 mapping is given that takes elements (cells) of the interval function to antidual pairs of elements in the locus function, and vice versa. A set of ν binary codewords representing the intervals are defined and used to generate the codewords of all genomic regions...
The cortical microvasculature plays a key role in cortical tissue health by transporting important molecules via blood. Disruptions to blood flow in the microvasculature due to events such as stroke can thus induce damage to the cortex. Recent developments in two-photon microscopy have enabled in vivo imaging of anesthetized rat cortex in three dimensions. The microscopy data provide information about...
Regulation of cell growth and proliferation has a fundamental role in tissue development, organogenesis, and disease progression. Conserved distribution of the number of sides of cells with a mean value of six was found in a variety of proliferating epithelia. Previous studies have shown that clones of proliferating cells bounded by quiescent cells have fewer sides than normal epithelia. However,...
Coarctation of the aorta is an obstruction of the aorta and is usually associated with other concomitant cardiovascular abnormalities especially with bicuspid aortic valve stenosis. The objectives of this study are, (1) to investigate the effects of coarctation on the hemodynamics in the aorta to gain a better understanding of the cause of certain post-surgical coarctation problems, (2) to develop...
Atherosclerotic lesions form non-randomly at locations in bends and bifurcations where the local flow can be classified as ‘disturbed flow’ and is associated with low shear stress oscillatory or reciprocating flow. Endothelial cells in vivo are constantly exposed to mechanical stimulation due to hemodynamic loading in the form of pulsatile pressure, cyclic stretch and shear stress to maintain phenotype...
This paper is concerned with computational modeling of a severe congenital defect called Hypoplastic left heart syndrome (HLHS) that is the most common cardiac malformation with the highest likelihood of deaths in newborns. A lumped parameter model of the HLHS circulation has been developed to study the hemodynamic variables in the various sections of the cardio-pulmonary circulation system. We applied...
Atherosclerosis develops from oxidized low-density lipoprotein molecules (LDL). When oxidized LDL evolves in plaque formations within an artery wall, a series of reactions occur to repair the damage to the artery wall caused by oxidized LDL. Macrophages accumulate inside arterial intima, they started to collect oxidized LDL and form foam cells. Smooth muscle cells accumulate in the atherosclerotic...
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