M.T. MARTIN^*, H.E. PEDRANZANI^**, R. SIERRA DE GRADO

BIOCELL, Vol.31, No.1, pp. 41-49, 2007, DOI:10.32604/biocell.2007.31.041

Abstract An in vitro collection has been established with selected European aspen from Palencia province (Spain). Currently, this collection includes 32 high quality clones, selected for their good bearing and healthy state. Most of them belong to different discrete local populations.
Populus tremula L. was propagated in proliferation Aspen Culture Medium; they required subculture every 3 months. The purpose of this study was, therefore, to select a medium which allows the maintenance of 32 clones for a period longer than 3 months without subculture and to observe the behavior of those clones in 15 different culture medium compositions. Seven… More >

B. Gatmiri¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.4, No.3, pp. 159-166, 2007, DOI:10.3970/icces.2007.004.159

Abstract This document summarizes the basic concepts and steps of establishment of the set of equations of wave propoagation in far field and of the dynamic behaviour of porous media in the near field. A breif description of HYBRID software as a powerful tool for evaluation of local seismic site effect is presented. The Combination of the FEM and BEM and improvement of numerical algorithm for the time truncation are described. More >

S. Okamoto¹, H. Noguchi²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.2, No.4, pp. 131-136, 2007, DOI:10.3970/icces.2007.002.131

Abstract This paper presents a control of walking robot by using inverse dynamics of link mechanisms, which has already been proposed and applied in several in-plane motions. In this method, FEM is used for the discretization of equations of motion. This method calculates nodal forces by evaluating equations of motion in a matrix form, and thus information from the entire system can be handled efficiently, and the torques input to each joint of link mechanisms to achieve required motion are calculated easily. This method is suitable to the feed-forward control of closed-loop or continuously link mechanisms. More >

Christine M. Scotti¹, Sergio L. Cornejo², Ender A. Finol³

The International Conference on Computational & Experimental Engineering and Sciences, Vol.1, No.1, pp. 41-48, 2007, DOI:10.3970/icces.2007.001.041

Abstract Abdominal aortic aneurysm (AAA) rupture is believed to represent the culmination of a complex vascular mechanism partially driven by the forces exerted on the arterial wall. In the present investigation, we present fully coupled fluid-structure interaction (FSI) and finite element analysis (FEA) computations of a patient-specific AAA model. This work advances previous FSI AAA modeling by including localized intraluminal thrombus and the comparison of FSI- and FEA-predicted wall stress distributions. The FSI transient fluid and wall dynamics resulted in a maximum wall stress 21% higher than that obtained with FEA, demonstrating the importance of modeling More >

F. Gao¹, D. Tang^2∗, Z. Guo³, Makoto Sakamoto⁴, T. Matsuzawa⁵

The International Conference on Computational & Experimental Engineering and Sciences, Vol.1, No.1, pp. 21-28, 2007, DOI:10.3970/icces.2007.001.021

Abstract Patients with aortic aneurysm, especially aortic arch aneurysm, are prone to aortic dissection. For investigation of the effects of aneurysm and wall stiffness on wall stress distribution, a nonaneurysm arch model as well as an aneurysm arch model was constructed. The fluid structure interaction was implemented in the arch model of aorta. The results show that the stresses are much higher at inflection points in the aneurysm model than in nonaneurysm model, and the stresses at media in stiffened wall are higher than in unstiffened wall. The high composite stress is located at inflection points More >

Christopher J. Hunter^∗,†, Sophia Bianchi^*, Phil Cheng^‡, Ken Muldrew^∗,‡

Molecular & Cellular Biomechanics, Vol.4, No.4, pp. 227-238, 2007, DOI:10.3970/mcb.2007.004.227

Abstract The nucleus pulposi of many species contain residual cells from the embryonic notochord, which exhibit a very unusual appearance (large vacuoles occupying ~80% of the cell volume, surrounded by an actin cytoskeleton). While the vacuoles have been qualitatively described, their composition and function has remained elusive. Given that these cells are believed to generate and experience significant osmotic pressures in both the notochord and intervertebral disc, we hypothesized that the vacuoles may serve as osmoregulatory organelles. Using both experimental and theoretical means, we demonstrated that the vacuoles contain a low-osmolality solution, generated via ion pumps More >

A. Sinha Roy^*, K. West^†, R. S. Rontala¹, R. K. Greenberg², R. K. Banerje^1,‡

Molecular & Cellular Biomechanics, Vol.4, No.4, pp. 211-226, 2007, DOI:10.3970/mcb.2007.004.211

Abstract Interventional treatment of aortic aneurysms using endovascular stentgrafting is a minimally invasive technique. Following device implantation, transient drag forces act on the stentgraft. When the drag force exceeds the fixation force, complications like stentgraft migration, endoleaks and stentgraft failure occur. In such a scenario the device becomes unstable, causing concern over the long-term durability of endovascular repairs. The objective of this study is: 1) to measure the drag force on iliac limb stentgraft, having a distal diameter that is half the size of the proximal end, in an in vitro experiment; 2) to calculate the drag… More >

Anat Ratnovsky^∗,†, Matthew Mellema^*, Steven S. An^∗,‡, Jeffrey J. Fredberg^*, Stephanie A. Shore^*

Molecular & Cellular Biomechanics, Vol.4, No.3, pp. 143-158, 2007, DOI:10.3970/mcb.2007.004.143

Abstract Obesity is a risk factor for asthma. The purpose of this study was to determine whether metformin, an agent used in the treatment of an obesity-related condition (type II diabetes), might have therapeutic potential for modifying the effects of obesity on airway smooth muscle (ASM) function. Metformin acts via activation of AMP-activated protein kinase (AMPK), a cellular sensor of energy status. In cultured murine ASM cells, metformin (0.2--2 mM) caused a dose-dependent inhibition of cell proliferation induced by PDGF (10^-8 M) and serotonin (10^-4 M). Another AMPK activator, 5-aminoimidazole-4-carboxamide-1-ß-D-riboruranoside (AICAR), also inhibited PDGF-induced proliferation. Furthermore, cells More >

J. S. Ren^*

Molecular & Cellular Biomechanics, Vol.4, No.1, pp. 55-66, 2007, DOI:10.3970/mcb.2007.004.055

Abstract Formation and rupture of aneurysms due to the inflation of an artery with collagen fibers distributed in two preferred directions, subjected to internal pressure and axial stretch are examined within the framework of nonlinear elasticity. A two layer tube model with a fiber-reinforced composite based incompressible anisotropic hyperelastic constitutive material is employed to model the stress-strain behavior of the artery wall with distributed collagen fibers. The artery wall takes up a uniform inflation deformation, and there are no aneurysms in the artery under the normal condition. But an aneurysm may be formed in arteries when… More >

Yan Liu¹, Xiong Zhang¹, K. Y. Sze², Min Wang¹

CMES-Computer Modeling in Engineering & Sciences, Vol.20, No.3, pp. 177-192, 2007, DOI:10.3970/cmes.2007.020.177

Abstract In molecular simulations, the frequencies of the low-frequency modes are many orders of magnitude lower than those of the high-frequency modes. Compared with the amplitudes of the low-frequency modes, the amplitudes of the high-frequency modes are often negligible and, thus, least interesting. As dictated by the period of the highest frequency mode, the critical time step for stable time integration can be significantly increased by suppressing the negligible high-frequency modes yet the solution remains virtually intact. In this light, a smoothed molecular dynamics (SMD) approach is proposed to eliminate the high-frequency modes from the dynamical… More >