G.A. Gravvanis¹, K.M. Giannoutakis²

CMES-Computer Modeling in Engineering & Sciences, Vol.71, No.4, pp. 305-330, 2011, DOI:10.3970/cmes.2011.071.305

Abstract In this paper we present parallel explicit approximate inverse matrix techniques for solving sparse linear systems on shared memory systems, which are derived using the finite element method for biharmonic equations in three space variables. Our approach for solving such equations is by considering the biharmonic equation as a coupled equation approach (pair of Poisson equation), using a FE approximation scheme, yielding an inner-outer iteration method. Additionally, parallel approximate inverse matrix algorithms are introduced for the efficient solution of sparse linear systems, based on an anti-diagonal computational approach that eliminates the data dependencies. Parallel explicit More >

Ying-Hsiu Shen¹, Chein-Shan Liu^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.71, No.2, pp. 157-178, 2011, DOI:10.3970/cmes.2011.071.157

Abstract When the local differential quadrature (LDQ) has been successfully applied to solve two-dimensional problems, the global method of DQ still has a problem by requiring to solve the inversions of ill-posed matrices. Previously, when one uses (n-1)th order polynomial test functions to determine the weighting coefficients with n grid points, the resultant n ×n Vandermonde matrix is highly ill-conditioned and its inversion is hard to solve. Now we use (m-1)th order polynomial test functions by n grid points that the size of Vandermonde matrix is m×n, of which m is much less than n. We More >

J.A. Ferreira^2,3, P. de Oliveira², P. Silva⁴, J.N. Murta⁵

CMES-Computer Modeling in Engineering & Sciences, Vol.71, No.1, pp. 1-14, 2011, DOI:10.3970/cmes.2011.071.001

Abstract Mathematical models to describe drug concentration profiles of topically administered drug in the anterior chamber aqueous humor have been proposed by several authors. The aim of this paper is to present a mathematical model to predict the drug concentration in the anterior chamber when a therapeutical contact lens with the drug entrapped in nanoparticles is used. More >

V.G.Yakhno¹

CMC-Computers, Materials & Continua, Vol.21, No.1, pp. 1-16, 2011, DOI:10.3970/cmc.2011.021.001

Abstract Homogeneous non-dispersive anisotropic materials, characterized by a positive constant permeability and a symmetric positive definite conductivity tensor, are considered in the paper. In these anisotropic materials, the electric and magnetic dyadic Green's functions are defined as electric and magnetic fields arising from impulsive current dipoles and satisfying the time-dependent Maxwell's equations in quasi-static approximation. A new method of deriving these dyadic Green's functions is suggested in the paper. This method consists of several steps: equations for electric and magnetic dyadic Green's functions are written in terms of the Fourier modes; explicit formulae for the Fourier More >

Claudia Ress¹, Alexander Tschoner¹, Christian Ciardi¹, Markus W. Laimer¹, Julia W. Engl¹, Wolfgang Sturm¹, Helmut Weiss², Herbert Tilg³, Christoph F. Ebenbichler¹, Josef R. Patsch¹, Susanne Kaser¹

European Cytokine Network, Vol.21, No.1, pp. 65-70, 2010, DOI:10.1684/ecn.2009.0177

Abstract Background. Matrix metalloproteinases (MMPs) and their specific inhibitors (tissue inhibitor of metalloproteinases [TIMPs]), are involved in adipogenesis, angiogenesis and remodeling of extracellular matrix. MMPs and TIMPs have been shown to be associated with various diseases such as neurological disorders, malig-nancies and cardiovascular disease. MMPs and TIMPs are thought to play a major role in extensive reorganization of the adipose tissue in obesity. Methods and materials. To test whether significant weight loss alters circulating MMPs and TIMPs, 18 morbidly obese women, who underwent bariatric surgery for weight loss, were investigated before and one year after surgery… More >

Carlos H. F. Chan, Assaad El-Hakim, Sero Andonian

Canadian Journal of Urology, Vol.17, No.2, pp. 5127-5130, 2010

Abstract Introduction: Matrix stones are rare types of urinary calculi composed of mucoproteins and mucopolysaccharides. Since isolated flank pain may be the only presenting symptom and routine radiographic studies are usually non-informative, diagnosis of such urinary calculi represents a clinical challenge. Traditionally, these matrix stones have been managed by either open pyelolithotomy or percutaneous nephrolithotomy (PCNL). Ureteroscopic management of a patient with matrix renal stones and review of literature is presented.
Case report: A 34-year-old woman presented with chronic right flank pain. Abdominal ultrasound found a 5.3 cm heterogeneous right renal pelvic mass with 9.7 mm stone. CT… More >

VANINA ANDREA FONTANA¹, MELISA SANCHEZ¹, ELISA CEBRAL² AND JUAN CARLOS CALVO^1,3*

BIOCELL, Vol.34, No.1, pp. 37-44, 2010, DOI:10.32604/biocell.2010.34.037

Abstract Implantation is one of the most regulated processes in human reproduction, by endocrine and immunological systems. Cytokines are involved in embryo-maternal communication and an impaired balance could result in pregnancy loss. Here we investigated the effect of interleukin 1-β on the activity of two important metalloproteinases (MMP-2 and MMP-9) that are involved in extracellular matrix remodeling as well as the secretion of leptin, one of the reproductive hormones actively regulating their activity and secretion. We found that IL-1β activates matrix metalloproteinase activity as well as increases leptin secretion. We propose that this interleukin, through the More >

Rami K Korhonen^∗,†, Sang-Kuy Han^‡, Walter Herzog^‡

Molecular & Cellular Biomechanics, Vol.7, No.3, pp. 125-134, 2010, DOI:10.3970/mcb.2010.007.125

Abstract Changes in the osmotic environment cause changes in volume of isolated cells and cells in tissue explants, and the osmotic environment becomes hypotonic in cartilage diseases such as osteoarthritis (OA). However, it is not known how cells respond to a hypotonic osmotic challenge when situated in the fully intact articular cartilage.
A confocal laser scanning microscope was used to image chondrocytes of intact rabbit patellae in an isotonic (300 mOsm) and hypotonic (172 mOsm) immersion medium. Cell volumes were calculated before and 5, 15, 60, 120 and 240 minutes after the change in saline concentration. Local… More >

Chein-Shan Liu¹, Hong-Ki Hong¹, Satya N. Atluri²

CMES-Computer Modeling in Engineering & Sciences, Vol.60, No.3, pp. 279-308, 2010, DOI:10.3970/cmes.2010.060.279

Abstract We propose novel algorithms to calculate the inverses of ill-conditioned matrices, which have broad engineering applications. The vector-form of the conjugate gradient method (CGM) is recast into a matrix-form, which is named as the matrix conjugate gradient method (MCGM). The MCGM is better than the CGM for finding the inverses of matrices. To treat the problems of inverting ill-conditioned matrices, we add a vector equation into the given matrix equation for obtaining the left-inversion of matrix (and a similar vector equation for the right-inversion) and thus we obtain an over-determined system. The resulting two modifications… More >

Metin Kök^1,2, Erdogan Kanca³

CMC-Computers, Materials & Continua, Vol.18, No.3, pp. 213-236, 2010, DOI:10.3970/cmc.2010.018.213

Abstract In this investigation, a new model was developed to predict the wear rate of Al2O3 particle-reinforced aluminum alloy composites by Genetic Expression Programming (GEP). The training and testing data sets were obtained from the well established abrasive wear test results. The volume fraction of particle, particle size of reinforcement, abrasive grain size and sliding distance were used as independent input variables, while wear rate (WR) as dependent output variable. Different models for wear rate were predicted on the basis of training data set using genetic programming and accuracy of the best model was proved with More >