Bio-Medical Materials and Engineering - Volume 24, issue 1

Authors: Wan, Chao | Hao, Zhi-Xiu | Wen, Shi-Zhu

Article Type: Research Article

Abstract: It is known that the anterior cruciate ligament (ACL) plays a role in providing joint stabilities under tibial varus/valgus torques and the material behavior of the ACL has changed with ageing. However, the effect of this variation of the ACL material property on joint kinematics and biomechanics under tibial varus/valgus torques has still not been clarified. In this paper, three finite element (FE) models of an intact tibiofemoral joint were reconstructed with different ACL material properties, corresponding to the ACL on the younger, middle and older ages, respectively. The joint kinematics, the stress distribution and resultant force of the …ACL were obtained under a tibial varus or valgus torque load. It was found that the variation in the ACL material property would result in great changes in some joint displacements (i.e., the tibial anterior translation and external rotation). The maximal stress value in the ACL had also altered while the stress distribution did not varied obviously. The great change in the tibial anterior translation illustrated that ACL played an important role against varus/valgus torques by controlling the coupled tibial anterior translation//external rotation rather than the corresponding varus/valgus rotation. Show more

Keywords: material property change, ageing, anterior cruciate ligament, tibiofemoral joint, finite element

DOI: 10.3233/BME-130941

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 1375-1382, 2014

Authors: Chen, Wen-Pei | Hung, Che-Lun | Tsai, Suh-Jen Jane | Lin, Yaw-Ling

Article Type: Research Article

Abstract: SNPs are the most abundant forms of genetic variations amongst species; the association studies between complex diseases and SNPs or haplotypes have received great attention. However, these studies are restricted by the cost of genotyping all SNPs; thus, it is necessary to find smaller subsets, or tag SNPs, representing the rest of the SNPs. In fact, the existing tag SNP selection algorithms are notoriously time-consuming. An efficient algorithm for tag SNP selection was presented, which was applied to analyze the HapMap YRI data. The experimental results show that the proposed algorithm can achieve better performance than the existing tag SNP …selection algorithms; in most cases, this proposed algorithm is at least ten times faster than the existing methods. In many cases, when the redundant ratio of the block is high, the proposed algorithm can even be thousands times faster than the previously known methods. Tools and web services for haplotype block analysis integrated by hadoop MapReduce framework are also developed using the proposed algorithm as computation kernels. Show more

Keywords: SNP, haplotype block, tag SNP selection, hadoop, non-redundant site, redundant ratio

DOI: 10.3233/BME-130942

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 1383-1389, 2014

Authors: Geng, D.Y. | Li, C.H. | Wan, X.W. | Xu, G.Z.

Article Type: Research Article

Abstract: To study the mechanism of cells subjected to external electromagnetic fields, the expression of cyclin kinase inhibitor p27 is analyzed in the four cell cycle phases. The regulatory functions are investigated in gap phase1 to synthesis, gap phase 2 to mitotic phase and post mitotic phase transition in the mammalian cell cycle processes. A mathematical model is developed to meet the general cell cycle regulatory network based on the molecular dynamics method. Phase plane analysis results show that the p27 over-expression can lead to the hysteresis effect of cell cycle processes and phase transition delay. It is an universal approach …to predict the key regulatory gene in signal transduction pathway. Show more

Keywords: Electromagnetic fields, Mathematical model, Molecular dynamics method, Cell cycle, Phase plane analysis

DOI: 10.3233/BME-130943

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 1391-1397, 2014

Authors: Wang, Huiya | Zhang, Shanwen

Article Type: Research Article

Abstract: Gene expression profiles have great potential for accurate tumor diagnosis. It is expected to enable us to diagnose tumors precisely and systematically, and also bring the researchers of machine learning two challenges, the curse of dimensionality and the small sample size problems. We propose a manifold learning based dimensional reduction algorithm named orthogonal local discriminant embedding (O-LDE) and apply it to tumor classification. Comparing with the classical local discriminant embedding (LDE), O-LDE aims to obtain an orthogonal linear projection matrix by solving an optimization problem. After being projected into a low-dimensional subspace by O-LDE, the data points of the same …class maintain their intrinsic neighbor relations, whereas the neighboring points of the different classes are far from each other. Experimental results on a public tumor dataset validate the effectiveness and feasibility of the proposed algorithm. Show more

Keywords: Tumor classification, local discriminant embedding (LDE), orthogonal local discriminant embedding (O-LDE)

DOI: 10.3233/BME-130944

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 1399-1405, 2014

Authors: Huang, You-Min | Chou, I-Chiang | Jiang, Cho-Pei | Wu, Yi-Syun | Lee, Shyh-Yuan

Article Type: Research Article

Abstract: The purpose of this study is to investigate the effect of implant neck design and cortical bone thickness by means of 3-D linearly elastic finite element analysis and to analyze primary and secondary stability of clinical evidence based on micromotion and principal stress. Four commercial dental implants, comparable in size, for a type IV bone and mandibular segments were created. Various parameters were considered, including the osseointegration condition (non- and full bonded), force direction (vertical and horizontal) and cortical bone thickness (0.3, 0.5 and 1mm). The force was considered a static load applied at the top of the platform. The …magnitudes of the vertical and horizontal loading direction were 500 N and 250 N. Micromotion and principal stresses were employed to evaluate the failure of osseointegration and bone overloading, respectively. The results show that Maximum stress of the peri-implant bone decreased as cortical bone thickness increased. The stress concentration regions were located at the implant neck between the cortical bone and cancellous bone. The micromotion level in full osseointegration is less than that in non-osseointegration and it also decreases as a increasing of cortical bone thickness. Consequently, cortical bone thickness is a key factor for primary stability. Show more

Keywords: Dental, Neck, Osseointegration, Mandible

DOI: 10.3233/BME-130945

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 1407-1415, 2014

Authors: Liu, Ke | Yao, Guangming | Yu, Zeyun

Article Type: Research Article

Abstract: Spatial-temporal calcium dynamics due to calcium release, buffering, and re-uptaking plays a central role in studying excitation-contraction (E-C) coupling in both healthy and defected cardiac myocytes. In our previous work, partial differential equations (PDEs) had been used to simulate calcium dynamics with realistic geometries extracted from electron microscopic imaging data. However, the computational costs of such simulations are very high on a single processor. To alleviate this problem, we have accelerated the numerical simulations of calcium dynamics by using graphics processing units (GPUs). Computational performance and simulation accuracy are compared with those based on a single CPU and another popular …parallel computing technique, OpenMP. Show more

Keywords: calcium dynamics, PDEs, parallel, OpenMP, CUDA, GPU

DOI: 10.3233/BME-130946

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 1417-1424, 2014