James D. Turner, Manoranjan Majji, John L. Junkins

The International Conference on Computational & Experimental Engineering and Sciences, Vol.16, No.1, pp. 9-10, 2011, DOI:10.3970/icces.2011.016.009

Abstract Numerical integration methods have been developed for predicting the evolution of the response of dynamical systems. Standard algorithms approach approximate the solution at a future time by introducing using a truncated power series representation that attempts to recover an n-th order Taylor series approximation, while only numerically sampling a single derivative model. Successful applications of this approach include: (1) Runge-Kutta methods which build up an approximation for a single step; (2) Predictor-Correction methods that use several back solutions to approximate the next step, and (3) Gear methods for handling stiff differential equations. The major innovation… More >

T. Sakai, W. Li, B. Lian, N. Oguma

The International Conference on Computational & Experimental Engineering and Sciences, Vol.16, No.1, pp. 7-8, 2011, DOI:10.3970/icces.2011.016.007

Abstract Long term use of mechanical products provides us a lot of positive environmental effects such as saving resources, saving energy, reducing environmental load to globe and reducing the industrial wastes. Thus, fatigue property of metallic materials in very high cycle regime such as gigacycles has been a new important subject to ensure the long durability of actual mechanical structures during the latest decades. From this point of view, fatigue tests in the long life regime were performed for various kinds of metallic materials by many researchers and a series of experimental results were reported. One… More >

LIU Yong-jie, TIAN Ren-hui, OUYANG Qiao-lin, WANG Qing-yuan

The International Conference on Computational & Experimental Engineering and Sciences, Vol.16, No.1, pp. 5-6, 2011, DOI:10.3970/icces.2011.016.005

Abstract Ti-6Al-4V is widely used in biology engineering as well medical implant. Clinical investigations show that TC4 implant could have rupture of passivation film and visible corrosion. To predict service life of the Ti-6Al-4V implant, it is necessary to study its ultra-high cycle fatigue behaviors in physiological environment exceeding 10⁷ cycles. In this paper, using the ultrasonic fatigue testing technique, the high cycle and ultra-high cycle fatigue properties of Ti-6Al-4V subjection to simulated body fluid (SBF) in body temperature were studied and compared with that of normal Ti-6Al-4V. The experimental results show that SBF subjection has slight… More >

Q. Chen, K. Kariya

The International Conference on Computational & Experimental Engineering and Sciences, Vol.16, No.1, pp. 3-4, 2011, DOI:10.3970/icces.2011.016.003

Abstract Abstract Al alloys have been widely used as engineering materials in many machines and structures because of their excellent properties such as high specific strength, high resistance to corrosion and easy to recycle. Especially, high strength Al alloys are effective to reduce environment load through achieving low fuel consumption in automobile engines. On the other hand, high strength Al alloys have no definite fatigue limit and their fatigue strengths are very low in comparison with their high static strengths. It is important to know the fatigue strength of high strength Al alloys in the long… More >

Yoshiyuki Furuya

The International Conference on Computational & Experimental Engineering and Sciences, Vol.16, No.1, pp. 1-2, 2011, DOI:10.3970/icces.2011.016.001

Abstract Gigacycle fatigue takes place in high-strength steel. In this case, fish-eye fracture eliminates a conventional fatigue limit. This means that the fish-eye fracture is a key to understand the gigacycle fatigue of high-strength steel. Evaluation of gigacycle fatigue properties needs accelerated fatigue testing since gigacycle fatigue tests take long time. For example, a 10⁹-cycles fatigue test takes more than 3 months at conventional 100 Hz. For this acceleration, ultrasonic fatigue testing is a very powerful tool since it achieves 20 kHz and completes the 10⁹-cycles in a day. However, frequency effects must sufficiently be investigated before… More >

Shu Q. Liu^∗,†, Brandon J. Tefft^*, Di Zhang^*, Derek Roberts^*, Daniel J. Schuster^*, Allison Wu^*

Molecular & Cellular Biomechanics, Vol.8, No.4, pp. 319-338, 2011, DOI:10.3970/mcb.2011.008.319

Abstract Myocardial ischemia, a disorder causing myocardial infarction and malfunction, can activate various adaptive mechanisms that protect cardiomyocytes from ischemic injury. During the early hours post myocardial ischemia, injured cardiac cells can release several molecules, including adenosine, opioids, and bradykinin, which promote myocardial survival by activating the G protein signaling pathways. During a later phase about several days, myocardial ischemia induces upregulation of growth factors and cytokines, including VEGF, ILGF, HGF, and SDF-1, in the injured myocardium, contributing to cardioprotection. In addition to the injured heart, the liver participates in cardioprotection. In response to myocardial ischemia, More >

Hana Chang^*, Melissa L. Knothe Tate^∗,†,‡

Molecular & Cellular Biomechanics, Vol.8, No.4, pp. 297-318, 2011, DOI:10.3970/mcb.2011.008.297

Abstract In the preceding study (Part A), we showed that prescribed seeding conditions as well as seeding density can be used to subject multipotent stem cells (MSCs) to volume changing stresses and that changes in volume of the cell are associated with changes in shape, but not volume, of the cell nucleus. In the current study, we aim to control the mechanical milieu of live cells using these prescribed seeding conditions concomitant to delivery of shape changing stresses via fluid flow, while observing adaptation of the cytoskeleton, a major cellular transducer that modulates cell shape, stiffness… More >

Joshua A. Zimmermann^*, Melissa L. Knothe Tate^∗,†,‡

Molecular & Cellular Biomechanics, Vol.8, No.4, pp. 275-296, 2011, DOI:10.3970/mcb.2011.008.275

Abstract Shape and fate are intrinsic manifestations of form and function at the cell scale. Here we hypothesize that seeding density and protocol affect the form and function of live embryonic murine mesenchymal stem cells (MSCs) and their nuclei. First, the imperative for study of live cells was demonstrated in studies showing changes in cell nucleus shape that were attributable to fixation per se. Hence, we compared live cell and nuclear volume and shape between groups of a model MSC line (C3H10T1/2) seeded at, or proliferated from 5,000 cells/cm2 to one of three target densities to… More >

Wangping Duan^∗, Lei Wei^†, Juntao Zhang^∗, Yongzhuang Hao^∗, Chunjiang Li^∗, Hao Li^∗, Qi Li^∗, Quanyou Zhang^‡, Weiyi Chen^‡, Xiaochun Wei^∗,§

Molecular & Cellular Biomechanics, Vol.8, No.4, pp. 253-274, 2011, DOI:10.3970/mcb.2011.008.253

Abstract The cytoskeleton network is believed to play an important role in the biomechanical properties of the chondrocyte. Ours and other laboratories have demonstrated that chondrocytes exhibit a viscoelastic solid creep behavior in vitro and that viscoelastic properties decrease in osteoarthritic chondrocytes. In this study, we aimed to understand whether the alteration of viscoelastic properties is associated with changes in cytoskeleton components of ageing chondrocytes from rabbit knee articular cartilage. Three age groups were used for this study: young (2-months-old, N=23), adult (8-months-old, N=23), and old (31-months-old, N=23) rabbit groups. Cartilage structure and proteoglycan and type II… More >

Di Pan^*, Yuhua Song^∗,†

Molecular & Cellular Biomechanics, Vol.8, No.3, pp. 233-252, 2011, DOI:10.3970/mcb.2011.008.233

Abstract Cytoskeletal restraints affect force-regulated integrin function in cell adhesion. However, the structural and molecular basis underlying the effect of cytoskeletal restraints on b1 integrin binding to fibronectin is still largely unknown. In this study, we used steered molecular dynamics simulations to investigate the changes in glycosylated b1 integrin-fibronectin binding and in conformation and structure of the glycosylated b1 I-like domain-FN-III9 - 10 complex caused by altered restraints applied to b1 I-like domain. The results revealed that imposition of the increased constraints on b1 integrin increased resistance to force-induced dissociation of the b1 I-like domain-fibronectin complex.… More >