Bio-Medical Materials and Engineering - Volume 24, issue 6

Authors: Chew, Kim Mey | Seman, Norhudah | Sudirman, Rubita | Yong, Ching Yee

Article Type: Research Article

Abstract: The development of human-like brain phantom is important for data acquisition in microwave imaging. The characteristics of the phantom should be based on the real human body dielectric properties such as relative permittivity. The development of phantom includes the greymatter and whitematter regions, each with a relative permittivity of 38 and 28 respectively at 10 GHz frequency. Results were compared with the value obtained from the standard library of Computer Simulation Technology (CST) simulation application and the existing research by Fernandez and Gabriel. Our experimental results show a positive outcome, in which the proposed mixture was adequate to represent real …human brain for data acquisition. Show more

Keywords: Relative permittivity, comparison, human-like brain phantom, CST simulation application

DOI: 10.3233/BME-141027

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2161-2167, 2014

Authors: Gao, Xiaoqing | Du, Jie | Fan, Guangbi | Yang, Chaoxian | Deng, Li | Yuan, Qionglan

Article Type: Research Article

Abstract: In this study, the effects of adenoviral-mediated glial cell line-derived neurotrophic factor (Ad-GDNF) on apoptosis of cultured bone marrow mesenchymal stem cells (BMSCs) induced by hydrogen peroxide (H2 O2 ) were investigated. After BMSCs infected with Ad-GDNF were treated with 500 μM H2 O2 at 37° C for 1 h, lactate dehydrogenase (LDH), MTT and TUNEL methods were used to detect cell viability and apoptosis. In addition, the levels of GDNF in the supernatants in BMSCs cultures were detected by ELISA, pro-inflammatory cytokines IL-6 and TNF-a in the supernatants and apoptosis-related protein Bax and Bcl-2 in cell pellets were …investigated. The results showed that H2 O2 treatment significantly induced apoptosis of BMSCs and decreased the viability of BMSCs. However, Ad-GDNF significantly reversed the effects of H2 O2 on BMSCs. Furthermore, Ad-GDNF significantly decreased the levels of IL-6 and TNF-a and increased Bcl-2/Bax ratio in BMSCs treated by H2 O2 . In conclusion, Ad-GDNF inhibits apoptosis of BMSCs induced by H2 O2 , and the mechanisms may be related to down-regulating the expression of IL-6 and TNF-a and up-regulating the ratio of Bcl-2/Bax in BMSCs. Show more

Keywords: Glial cell line-derived neurotrophic factor, bone marrow mesenchymal stem cells, hydrogen peroxide, apoptosis

DOI: 10.3233/BME-141028

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2169-2176, 2014

Authors: Mirzasadeghi, Alireza | Narayanan, Sri Subanesh | Ng, Min Hwei | Sanaei, Reza | Cheng, Chen Hui | Bajuri, Mohd Yazid | Shukur, Mohammad Hassan

Article Type: Research Article

Abstract: The application of bone substitutes and cements has a long standing history in augmenting fractures as a complement to routine fracture fixation techniques. Nevertheless, such use is almost always in conjunction with definite means of fracture fixation such as intramedullary pins or bone plates. The idea of using biomaterials as the primary fixation bears the possibility of simultaneous fixation and bone enhancement. Intramedullary recruitment of bone cements is suggested in this study to achieve this goal. However, as the method needs primary testings in animal models before human implementation, and since the degree of ambulation is not predictable in animals, …this pilot study only evaluates the outcomes regarding the feasibility and safety of this method in the presence of primary bone fixators. A number of two sheep were used in this study. Tibial transverse osteotomies were performed in both animals followed by external skeletal fixation. The medullary canals, which have already been prepared by removing the marrow through proximal and distal drill holes, were then injected with calcium phosphate cement (CPC). The outcomes were evaluated postoperatively by standard survey radiographs, morphology, histology and biomechanical testings. Healing processes appeared uncomplicated until week four where one bone fracture recurred due to external fixator failure. The results showed 56% and 48% cortical thickening, compared to the opposite site, in the fracture site and proximal and distal diaphyses respectively. This bone augmentative effect resulted in 264% increase in bending strength of the fracture site and 148% increase of the same value in the adjacent areas of diaphyses. In conclusion, IMCO, using CPC in tibia of sheep, is safe and biocompatible with bone physiology and healing. It possibly can carry the osteopromotive effect of the CPCs to provide a sustained source of bone augmentation throughout the diaphysis. Although the results must be considered preliminary, this method has possible advantages over conventional methods of bone fixation at least in bones with compromised quality (i.e. osteoporosis and bone cysts), where rigid metal implants may jeopardize eggshell cortices. Show more

Keywords: Intramedullary cement osteosynthesis (IMCO), calcium phosphate cement (CPC), biomaterial, fracture, impending fracture, osteoporosis, internal fixation

DOI: 10.3233/BME-141029

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2177-2186, 2014

Authors: Feng, Xiaoli | Sun, Ting | Liu, Ruoyu | Zhang, Yanli | Chen, Aijie | Shao, Longquan

Article Type: Research Article

Abstract: This study aimed to evaluate the influence of mesoporous silica coating surface treatments on push-out bond strength of zirconia posts. Zirconia posts (Cosmopost) were treated with vehicle (control), sandblasting plus silane application (SB+SI), a combination of sandblasting, mesoporous silica coating and silane application (SB+MSC+SI) (n=10/group). Specimens were cemented with RelyX Unicem (3M ESPE, Germany) then horizontally segmented into three sections and subjected to a push-out test. Surface treatments showed significant higher bond strength than the control group, and SB+MSC+SI group presented higher values than SB+SI group (P<0.05). No significant differences were found in bond strength among root regions (P>0.05). We …conclude that the combination of mesoporous silica coating and silane application greatly enhance the push-out bond strength of zirconia posts. Show more

Keywords: Zirconia, posts, mesoporous silica coating, push-out, root region

DOI: 10.3233/BME-141030

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2187-2195, 2014

Authors: Yang, Tian | Yang, Xiao-Lu | Zhang, Yu-Shuai | Xiao, BaoLin | Hong, Jun

Article Type: Research Article

Abstract: Direct electrochemistry of glucose oxidase (GOD) was achieved when an ionic liquid/GOD-Polyhydroxy-C60 functional membrane was confined on a glassy carbon electrode (GCE). The cyclic voltammograms (CVs) of the modified GCE showed a pair of redox peaks with a formal potential (E°') of − 329±2 mV. The heterogeneous electron transfer constant (ks ) was 1.43 s-1. The modified GCE response to glucose was linear in the range from 0.02 to 2.0 mM. The detection limit was 1 μM. The apparent Michaelis-Menten constant (Km app ) was 1.45 mM.

Keywords: Glucose oxidase, polyhydroxy-C60, ionic liquid, direct electrochemistry

DOI: 10.3233/BME-141031

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2197-2202, 2014

Authors: Burham, Norhafizah | Hamzah, Azrul Azlan | Majlis, Burhanuddin Yeop

Article Type: Research Article

Abstract: This paper studies parameters which affect the pore size diameter of a silicon membrane. Electrochemical etching is performed in characterise the parameter involved in this process. The parameter has been studied is volume ratio of hydrofluoric acid (HF) and ethanol as an electrolyte aqueous for electrochemical etch. This electrolyte aqueous solution has been mixed between HF and ethanol with volume ratio 3:7, 5:5, 7:3 and 9:1. As a result, the higher volume of HF in this electrolyte gives the smallest pore size diameter compared to the lower volume of HF. These samples have been dipped into HF and ethanol electrolyte …aqueous with supplied 25 mA/cm2 current density for 20, 30, 40, and 50 minutes. The samples will inspect under Scanning Electron Microscope (SEM) to execute the pore formations on silicon membrane surface. Show more

Keywords: Silicon membrane, volume ratio, hydrofluoric acid (HF), electrochemical etch, nanoporous

DOI: 10.3233/BME-141032

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2203-2209, 2014

Authors: Zhang, Hong-Yu | Sun, Yan-Fang | Sun, Yu-Long | Zhou, Ming

Article Type: Research Article

Abstract: Significant progress has been achieved in the field of pH-sensitive drug delivery system in recent years. For layer-by-layer self-assembly nanocarriers, various pH values can induce the change of permeability and structural stability of the outer polyelectrolyte multi-layers, resulting in the release of the loaded drug. In the present study, carboxyl-modified mesoporous silica nanoparticles (MSNs-COOH) were prepared as reservoirs to hold model cargo, i.e. Rhodamine B (RhB). Polycations, including 1, 4-butanediamine (BDA)-modified linear poly (glycerol methacrylate) (L-B) or BDA-modified star-shaped poly (glycerol methacrylate) (S5-B) and 1,2-ethanediamine (EDA)-modified star-shaped poly (glycerol methacrylate) (S5-E), and polyanion, i.e. poly (acrylic acid) (PAA), are self-assembled …by electrostatic interactions as coating. The loading process of RhB was characterized by transmission electron microscopy, Fourier transform infrared spectroscopy, thermo-gravimetric analysis, and dynamic light scattering, and the release of RhB was controlled by changing the pH of phosphate buffer saline. The results showed that the loading capacity and entrapment efficiency of RhB were the highest for S5-B/PAA, which were 10.1% and 44.4%, respectively. In addition, the release of RhB was about 90% at pH 2.0 and 35% at pH 7.4, which was indicative of obvious pH-responsivity. The MSNs-COOH coated by S5-B/PAA proposed in the present study show potential applications in targeted drug delivery. Show more

Keywords: Layer-by-layer, mesoporous silica nanoparticles, poly (glycerol methacrylate), pH-responsivity

DOI: 10.3233/BME-141033

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2211-2218, 2014

Authors: Shen, Zhe | Wang, Lili | Zhao, Yaqian | Zhao, Qinping | Zhao, Meng

Article Type: Research Article

Abstract: Skin synthesis is important for the actual appearance of digital human models. However, it is difficult to design a general algorithm to efficiently produce high quality results. This paper proposes a parallel texture synthesis method for large scale skin of digital human models. Two major procedures are included in this method, a parallel matching procedure and a multi-pass optimizing procedure. Compared with other methods, this algorithm is easy to use, requires only a small size of skin image as input, and generates an arbitrary size of skin texture with high quality. As demonstrated by experiments, the effectiveness of this skin …texture synthesis method is confirmed. Show more

Keywords: Texture synthesis, virtual human, parallel computing, L2 normal form

DOI: 10.3233/BME-141034

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2219-2227, 2014

Authors: Gao, Jianling | Yue, Shihong | Chen, Jun | Wang, Huaxiang

Article Type: Research Article

Abstract: Biological tissue impedance spectroscopy can provide rich physiological and pathological information by measuring the variation of the complex impedance of biological tissues under various frequencies of driven current. Electrical Impedance Tomography (EIT) technique can measure the impedance spectroscopy of biological tissue in medical field. Before application, a key problem must be solved on how to generally distinguish normal tissues from the cancerous in terms of measurable EIT data. In this paper, the impedance spectroscopy characteristics of human lung tissue are studied. On the basis of the measured data of 109 lung cancer patients, Cole-Cole Circle radius (CCCR) and the complex …modulus are extracted. In terms of the two characteristics, 71.6% and 66.4% samples of cancerous and normal tissues can be correctly classified, respectively. Furthermore, two characteristics of the measured EIT data of each patient consist of a two-dimensional vector and all such vectors comprise a set of vectors. When classifying the vector set, the rate of correctly partitioning normal and cancerous tissues can be raised to 78.2%. The main factors to affect the classification results on normal and cancerous tissues are generally analyzed. The proposed method will play an important role in further working out an efficient and feasible diagnostic method for potential lung cancer patients, and provide theoretical basis and reference data for electrical impedance tomography technology in monitoring pulmonary function. Show more

Keywords: Cancerous tissue, normal tissue, classification, electrical impedance spectroscopy

DOI: 10.3233/BME-141035

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2229-2241, 2014

Authors: Su, Wen-Ta | Chen, Xiao-Wei

Article Type: Research Article

Abstract: Stem cells from human exfoliated deciduous teeth (SHEDs) are mesenchymal stem cells isolated from the exfoliated human deciduous incisor that can differentiate into a many cell types. In this study, we evaluated the effect of liquorice or angelica extracts on the hepatic differentiation potential of SHEDs cells. SHEDs cells cultured in medium containing liquorice extracts were analyzed for 1) changes in cellular morphology, 2) changes in hepatic gene expression, AFP (Alpha-fetoprotein) and ALB (Albumin), and 3) albumin secretion and urea synthesis activity. Our data show that the hepatic differentiation potential of SHEDs cells is enhanced by the presence of liquorice …or angelica extracts in the culture medium. Our findings present new therapeutic possibilities for liver damage repair. Show more

Keywords: SHEDs, liquorice, angelica, differentiation, hepatocytes

DOI: 10.3233/BME-141036

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2243-2247, 2014

Authors: Dinescu, Sorina | Ionita, Mariana | Pandele, Andreea Madalina | Galateanu, Bianca | Iovu, Horia | Ardelean, Aurel | Costache, Marieta | Hermenean, Anca

Article Type: Research Article

Abstract: Extensively studied nowadays, graphene oxide (GO) has a benefic effect on cell proliferation and differentiation, thus holding promise for bone tissue engineering (BTE) approaches. The aim of this study was not only to design a chitosan 3D scaffold improved with GO for optimal BTE, but also to analyze its physicochemical properties and to evaluate its cytocompatibility and ability to support cell metabolic activity and proliferation. Overall results show that the addition of GO in the scaffold's composition improved mechanical properties and pore formation and enhanced the bioactivity of the scaffold material for tissue engineering. The new developed CHT/GO 3 wt% …scaffold could be a potential candidate for further in vitro and in vivo osteogenesis studies and BTE approaches. Show more

Keywords: Chitosan, graphene oxide, 3D scaffold, biocompatibility, bone tissue engineering

DOI: 10.3233/BME-141037

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2249-2256, 2014

Authors: Bai, Xinlei | Yilin, Chen | Qi, Xufeng | Cai, Dongqing

Article Type: Research Article

Abstract: Recent studies revealed that BDNF-TrkB pathway plays an important role in cardiac microvascular endothelial cells (CMECs) mediated myocardial angiogenesis. Single-cell analysis is a powerful tool for studying gene expression in individuals since cellular heterogeneity and dynamic microenvironments which individual cell will experience. Little is currently known about the expression of BDNF and TrkB receptors at the single CMEC level. Our single-cell analysis of seven randomly selected CMECs for BDNF and TrkB receptors (FL, T1, T2) showed that under an in vitro culture environment, BDNF was expressed in two of the seven selected CMECs. None of the single CMEC expressed TrkB-FL. …TrkB-T1 was expressed in all seven selected CMECs, while, TrkB-T2 was expressed in three of these. In addition, none of single CMEC was found to express both BDNF and three TrkB receptors or BDNF and TrkB-FL simultaneously. These results suggest that a stochastic or random expression pattern for BDNF and their receptors might be set in each of the CMEC to response requirement of the time and spatial change, regulation or pathophysiological change. Show more

Keywords: Single cell, BDNF, TrkB receptor, cardiac microvascular endothelial cells

DOI: 10.3233/BME-141038

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2257-2264, 2014

Authors: Liu, Yun-Feng | Zhang, Peng-Yuan | Zhang, Qiao-Fang | Zhang, Jian-Xing | Chen, Jie

Article Type: Research Article

Abstract: Three dimensional (3D) forces are the key factors for determining movement of teeth during orthodontic treatment. Designing precise forces and torques on tooth before treatment can result accurate tooth movements, but it is too difficult to realize. In orthodontic biomechanical systems, the periodontal tissues, including bones, teeth, and periodontal ligaments (PDL), are affected by braces, and measuring the forces applied on the teeth by braces should be based on a simulated model composed of these three types of tissues. This study explores the design and fabrication of a simulated oral model for 3D orthodontic force measurements. Based on medical image …processing, tissue reconstruction, 3D printing, and PDL simulation and testing, a model for measuring force was designed and fabricated, which can potentially be used for force prediction, design of treatment plans, and precise clinical operation. The experiment illustrated that bi-component silicones with 2:8 ratios had similar mechanical properties to PDL, and with a positioning guide, the teeth were assembled in the mandible sockets accurately, and so a customized oral model for 3D orthodontic force measurement was created. Show more

Keywords: Orthodontic force measurement, oral model, reconstruction, 3D printing

DOI: 10.3233/BME-141039

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2265-2271, 2014

Authors: Kwon, Yuri | Park, Sang-Hoon | Kim, Ji-Won | Ho, Yeji | Jeon, Hyeong-Min | Bang, Min-Jung | Koh, Seong-Beom | Kim, Jong-Hyun | Eom, Gwang-Moon

Article Type: Research Article

Abstract: This study aims at the quantification of fine change in parkinsonian rigidity at the wrist during deep brain stimulation (DBS) using a portable measurement system and objective mechanical measures. The rigidity of fourteen limbs was evaluated during DBS surgery. The resistive torque to imposed movement was measured for every setting where a reduction in rigidity was perceived by a neurologist. Quantitative mechanical measures derived from experimental data included viscoelastic properties, work, impulse and mechanical impedance. Most mechanical measures could discriminate the optimal setting from baseline (electrode at stereotactic initial position without electrical stimulation) and the highest significance was achieved by …viscous damping constant (p<0.001). Spearman correlation coefficients between mechanical measures and clinical score for multiple settings (averaged for 14 limbs) were 0.51–0.77 and the best correlation was shown for viscosity (ρ=0.77±0.22). The results suggest that intraoperative quantification of rigidity during DBS surgery is possible with the suggested system and measures, which would be helpful for the adjustment of electrode position and stimulation parameters. Show more

Keywords: Intraoperative, quantification, rigidity, DBS surgery, Parkinson's disease

DOI: 10.3233/BME-141040

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2273-2281, 2014

Authors: Wanyan, Xiaoru | Zhuang, Damin | Zhang, Huan

Article Type: Research Article

Abstract: Behavioral performance, subjective assessment based on NASA Task Load Index (NASA-TLX), as well as physiological measures indexed by electrocardiograph (ECG), event-related potential (ERP), and eye tracking data were used to assess the mental workload (MW) related to flight tasks. Flight simulation tasks were carried out by 12 healthy participants under different MW conditions. The MW conditions were manipulated by setting the quantity of flight indicators presented on the head-up display (HUD) in the cruise phase. In this experiment, the behavioral performance and NASA-TLX could reflect the changes of MW ideally. For physiological measures, the indices of heart rate variability (HRV), …P3a, pupil diameter and eyelid opening were verified to be sensitive to MW changes. Our findings can be applied to the comprehensive evaluation of MW during flight tasks and the further quantitative classification. Show more

Keywords: Mental workload, physiological measures, comprehensive evaluation, flight simulation, ergonomics

DOI: 10.3233/BME-141041

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2283-2290, 2014

Authors: Kwon, Yuri | Kim, Ji-Won | Ho, Yeji | Jeon, Hyeong-Min | Bang, Min-Jung | Eom, Gwang-Moon | Koh, Seong-Beom

Article Type: Research Article

Abstract: Patients with Parkinson's disease (PD) suffer from an increased resistance to passive movement of a joint, called as rigidity. Stretch reflex and shortening reaction were suggested to be associated to the rigidity, however, the mechanism is still poorly understood. We hypothesized that the co-contraction of antagonistic muscle pairs is enhanced in patients with PD and this induces resistance persisting throughout its range of motion. To test the hypothesis, we developed a motorized device for application of passive movement of the wrist joint and investigated the co-contraction of muscles during passive movement. It consisted of a servo motor connected to a …rotating axis with a timing belt, load cell for the measurement of resistance, and other elements for the fixation of arm and hand. Repetitive passive movement was applied to the wrist joint of patients. Co-contraction of antagonistic muscle pairs was significantly greater in patients than in normal subjects (p<0.001), suggesting that the enhanced co-contraction is associated with the mechanical resistance during passive movement, i.e. rigidity. Co-contraction during extended state was greater than the other states (p<0.001), which implies that the length-feedback mechanism may play the important role in co-contraction. Show more

Keywords: Parkinson's disease, rigidity, co-contraction, motorized device, passive movement

DOI: 10.3233/BME-141042

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2291-2297, 2014

Authors: Li, Xin | Zhong, Yongmin | Jazar, Reza | Subic, Aleksandar

Article Type: Research Article

Abstract: Modeling of thermal-induced mechanical behaviors of soft tissues is of great importance for thermal ablation. This paper presents a method by integrating the heating process with thermal-induced mechanical deformations of soft tissues for simulation and analysis of the thermal ablation process. This method combines bio-heat transfer theories, constitutive elastic material law under thermal loads as well as non-rigid motion dynamics to predict and analyze thermal-mechanical deformations of soft tissues. The 3D governing equations of thermal-mechanical soft tissue deformation are discretized by using the finite difference scheme and are subsequently solved by numerical algorithms. Experimental results show that the proposed method …can effectively predict the thermal-induced mechanical behaviors of soft tissues, and can be used for the thermal ablation therapy to effectively control the delivered heat energy for cancer treatment. Show more

Keywords: Thermal ablation, soft tissue, bio-heat transfer, thermo-mechanical deformation

DOI: 10.3233/BME-141043

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2299-2310, 2014

Authors: Liu, Shuang | Wanyan, Xiaoru | Zhuang, Damin

Article Type: Research Article

Abstract: To predict changes of situation awareness (SA) for pilot operating with different display interfaces and tasks, a qualitative analysis and quantitative calculation joint SA model was proposed. Based on the situational awareness model according to the attention allocation built previously, the pilot cognitive process for the situation elements was analyzed according to the ACT-R (Adaptive Control of Thought, Rational) theory, which explained how the SA was produced. To verify the validity of this model, 28 subjects performed an instrument supervision task under different experiment conditions. Situation Awareness Global Assessment Technique (SAGAT), 10-dimensional Situational Awareness Rating Technique (10-D SART), performance measure …and eye movement measure were adopted for evaluating SAs under different conditions. Statistical analysis demonstrated that the changing trend of SA calculated by this model was highly correlated with the experimental results. Therefore the situational awareness model can provide a reference for designing new cockpit display interfaces and help reducing human errors. Show more

Keywords: Situation awareness, ACT-R, analysis model, mathematical model, ergonomics

DOI: 10.3233/BME-141044

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2311-2318, 2014

Authors: Kim, Byeong Sam | Lim, Tae-Hong | Kwon, Tae Kyu | Han, Kap-Soo

Article Type: Research Article

Abstract: This study investigated that the spinal MFs can create compressive follower loads (CFLs) in the lumbar spine in a dynamic state. Three-dimensional optimization and finite element (FE) models of the spinal system were developed and validated using reported experimental data. An optimization analysis was performed to determine the MFs that create CFLs in the lumbar spine in various sagittal postures from 10° extension to 40° flexion. Optimization solutions for the MFs, CFLs, and follower load path (FLP) location were feasible for all studied postures. The FE predictions demonstrated that MFs which created CFLs along the base spinal curve connecting the …geometrical centers or along a curve in its vicinity (within anterior or posterior shift by 2 mm) produced stable deformation of the lumbar spine in the neutral standing and flexed postures, whereas the MFs which created the smallest CFLs resulted in unstable deformation. For extended postures, however, finding CFLs creating MFs that produce stable deformation of the extended spine was not possible. The results of this study support the hypothesis that the spinal muscles may stabilize the spine via the CFL mechanism. Show more

Keywords: Compressive follower load, muscle forces, finite element model, lumbar Spine, spine biomechanics

DOI: 10.3233/BME-141045

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2319-2329, 2014

Authors: Awoukeng-Goumtcha, A. | Taddei, L. | Tostain, F. | Roth, S.

Article Type: Research Article

Abstract: This study aims to investigate the penetration of a projectile into a surrogate human tissue numerically, using Finite Element (FE) simulation. 20% Balistic Gelatin material (BG) is simulated with an elasto-plastic hydrodynamic constitutive law, and then impacted by steel spheres at different velocities. The results from the FE simulations are compared with existing experimental data and other analytical equations from the literature. To our knowledge, this is the first study to investigate a projectile penetration by numerical simulation, and then compare the results with analytical and experimental data from previous studies. This developed model gives encouraging results for further investigations …of penetrating impact of projectile in the human body. Show more

Keywords: Penetrating impact, finite element analysis, ballistic, biomechanics, human surrogate

DOI: 10.3233/BME-141046

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2331-2339, 2014

Authors: Pan, Qing | Wang, Ruofan | Reglin, Bettina | Fang, Luping | Pries, Axel R. | Ning, Gangmin

Article Type: Research Article

Abstract: Estimation of the boundary condition is a critical problem in simulating hemodynamics in microvascular networks. This paper proposed a boundary estimation strategy based on a particle swarm optimization (PSO) algorithm, which aims to minimize the number of vessels with inverted flow direction in comparison to the experimental observation. The algorithm took boundary values as the particle swarm and updated the position of the particles iteratively to approach the optimization target. The method was tested in a real rat mesenteric network. With random initial boundary values, the method achieved a minimized 9 segments with an inverted flow direction in the network …with 546 vessels. Compared with reported literature, the current work has the advantage of a better fit with experimental observations and is more suitable for the boundary estimation problem in pulsatile hemodynamic models due to the experiment-based optimization target selection. Show more

Keywords: Microcirculation, particle swarm optimization, mathematical model, boundary condition

DOI: 10.3233/BME-141047

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2341-2347, 2014

Authors: Zhao, Qiuyun | Qian, Xiuqing | Li, Lin | Sun, Weijian | Huang, Shan | Liu, Zhicheng

Article Type: Research Article

Abstract: The aim of this study was to examine shape the changes of the lamina cribrosa (LC) under different intraocular pressures (IOPs) with different periods. Images of the optic nerve head were obtained using enhanced depth imaging spectral domain optical coherence tomography (EDI SD-OCT). After an initial scan of the IOP at native pressure, subsequent scanning was taken when the IOP values reached 40, 60, 80 and 100 mm Hg. Then scans continued with the IOP maintained at 100 mm Hg for 1 hour, 2 hours, 3 hours and 4 hours. The thicknesses of the LC and prelaminar tissue were measured …and the curvature of the LC was calculated. Our study found that as IOP increased, the thicknesses of both LC and prelaminar tissue decreased and the thickness variation of the LC correlated significantly with the increases of IOP when IOP was higher than 60 mm Hg. An exponential function was proposed to express the relationship between IOP and the thickness variations of LC and prelaminar tissue. Creep curves of the LC and prelaminar tissue was also obtained using the Prony model. In conclusion, both the thickness of the prelaminar tissue and LC thinned as the IOP elevated. The thickness of the LC also decreased after 4 hours of constant 100 mm Hg pressure. Show more

Keywords: Laminar cribrosa, prelaminar tissue, curvature, high intraocular pressure, EDI-OCT

DOI: 10.3233/BME-141048

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2349-2360, 2014

Authors: Ye, Xia | Wang, Ze | Zhang, Xianghua | Zhou, Ming | Cai, Lan

Article Type: Research Article

Abstract: In order to study how the geometric parameters and shape of the micro-structure surface of a bionic heart valve affects hemocompatibility, mastoid micro-structures with different periodic space were fabricated using a femtosecond laser on a polyurethane (PU) surface. The apparent contact angles of droplets on the micro-structure surfaces were measured to characterize their wettability. Then a series of blood compatibility experiments, including platelet adhesion, dynamic coagulation and hemolysis were completed. The experimental results showed that the micro-structure on the biomaterial surface helped improve its hydrophobicity and hemocompatibility. Also, the periodic space affected not only the hydrophobicity but also the hemocompatibility …of the biomaterial. With the increasing of the periodic space, the apparent contact angle increased, the number of platelet adhesion decreased, the dynamic clotting time became longer and the hemolysis ratio reduced. In addition, the shape of the micro-structure also affected the hemocompatibility of the biomaterial. Show more

Keywords: Hemocompatibility, micro-structure surface, polyurethane, periodic space, bionic heart valve

DOI: 10.3233/BME-141049

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2361-2369, 2014

Authors: Zhang, Chi | Li, Shuyu | Pu, Fang | Fan, Yubo | Li, Deyu

Article Type: Research Article

Abstract: The anatomic variation of Circle of Willis (CoW) has great impact on its compensatory capacity during stroke and cerebral ischemia. In the present study, a series of lumped parameter models were developed and used to simulate the effect of postural changes on the cerebral blood flow in ICA stenosis patients with different anatomic variants of the CoW. The results showed that the asymmetric distribution of cerebral blood flow caused by stenosis was attenuated in standing position in complete and half-complete CoW. However, in incomplete CoW, the decrease in blood flow in the ipsilateral cerebral arteries caused by unilateral ICA stenosis …was dramatic in both supine and standing positions, a likely result of inadequate collateral circulation within the CoW. In conclusion, the anatomic variation of CoW plays a significant role in maintaining the balance of cerebral blood supply in patients with ICA stenosis, especially during postural change. Show more

Keywords: Circle of Willis, internal carotid artery stenosis, anatomic variation, lumped parameter model, posture change

DOI: 10.3233/BME-141050

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2371-2380, 2014

Authors: Fu, Rongchang | Mahemut, Dilinaer | Tiyipujiang, Rexiati | Aihemaiti, Kuwahan | Ainiwaierjiang, Nuerya

Article Type: Research Article

Abstract: This paper studies the effect of Uyghur sand therapy on dynamics of arterial flow of knee joints via experiments and numerical simulations. Experiments have been carried out on 30 volunteers, with their diameter and flow rate of arteries of knee joints measured before and after Uyghur sand therapy. It has been found that Uyghur sand therapy will increase the inner diameter of knee arteries and speed up the blood flow. Experimental results show that Uyghur sand therapy can help relieve obstacles in local blood flow. By choosing one volunteer for CT scanning, three-dimensional reconstruction of knee-joint arteries via MIMICS software …is achieved. Calculation model is the established with numerical calculations performed by ANSYS software. According to the calculations, the blood flow of the knee arteries speeds up and the uniform distribution of velocity enlarges after Uyghur sand therapy, which further confirms the experimental results. Besides, the research also suggests that Uyghur sand therapy has stronger effect on blood flow of knee-joint arteries than the inner diameter. Show more

Keywords: Uyghur sand therapy, hemodynamics, finite element analysis, velocity of blood flow

DOI: 10.3233/BME-141051

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2381-2388, 2014

Authors: Lee, Jeong Jae | Lee, Jae Jin | Kim, Do Hyun | You, Sung (Joshua) Hyun

Article Type: Research Article

Abstract: An instrument-assisted soft tissue mobilization (IASTM) technique has recently been used specifically to inhibit hypertonic muscles and to lengthen muscle fiber shortness. However, it is unknown whether IASTM will show such promising inhibition effects on excessive ankle plantarflexion following stroke. Therefore, the purpose of this study was to use electromyographic (EMG) analysis to determine the ability of IASTM to reduce gastrocnemius (GCM) hypertonicity and concurrently facilitate tibialis anterior (TA) lengthening in a stroke patient. EMG activity on the patient's TA and GCM was measured before and after applying IASTM. After the intervention, the GCM was deactivated by 43%, and TA …activity increased by 150%, indicating IASTM-induced inhibition of the overactive GCM. The neuromobilization technique using IASTM showed a promising improvement of neuromuscular imbalance between TA and GCM activations, which can increase gait performance in a stroke case. Show more

Keywords: Instrument-Assisted Soft Tissue Mobilization (IASTM), Electromyography (EMG), stroke, gait

DOI: 10.3233/BME-141052

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2389-2394, 2014

Authors: Yu, Chang Ho | Hong, Chul Un | Kang, Seung Rok | Kwon, Tae Kyu

Article Type: Research Article

Abstract: The aim of this study is to verify the effect of indoor horse riding exercise on basal physical exercise and lumbar muscular function. The subjects included were 20 healthy females, who participated in the horse riding exercise using SRider (Rider Co. & ChonbuK National Univ, Korea) for 30 minutes per day, 3 days per week, over a period of 8 weeks. The subjects were divided into 4 groups as follows, with 10 subjects in each group: Postural Balance Exercise mode (PBE), Abdomen Exercise mode (ADE), Whole body Exercise mode (WBE), and Multiple Exercise (MTE). Isokinetic muscular function test was performed …before and after the horse riding exercise, to assess the effect of horse riding on basal physical exercise and lumbar muscular function. The test result on basal physical exercise and isokinetic muscular function showed improvements with variable degree in the back muscle strength, maximum joint torque, total work, and muscular acceleration time. The result signifies that the horse riding is an antagonistic exercise mainly performed on waist and abdomen area, and the machine induces persistent muscle contraction and causes myotonic induction enhancing the muscle strength. Indoor horse riding exercise proved its effectiveness for senior or the disabled people who need muscle exercises but have difficulties performing outdoor activities. Show more

Keywords: Horse riding, exercise effect, exercise instrument for indoor

DOI: 10.3233/BME-141053

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2395-2405, 2014

Authors: Yu, Chang Ho | Kim, Ui Ryeong | Kwon, Tae Kyu

Article Type: Research Article

Abstract: In this study, we assessed indoor horse riding exercise's effects on basal physical exercise and activities of daily living (ADL) function using horse riding equipment, involving elderly test subjects (in their sixties). The participants were 20 people with no impediment to activity. They participated in experiments that lasted 60 min per day, 3 days per week, over 8 weeks, using the “SRider” (Rider Co. and Chonbuk National University Korea).We measured trunk flexion, sit-up, whole-body reaction, leg strength, and maximal oxygen uptake as basal physical fitness parameters. Also, 3-m gait, single stance with eyes open, and single stance with eyes closed, …as ADL functions, were estimated once per month. The leg strength and whole body reaction result were significantly higher than before the exercise program. Moreover, the results of the 3-m walking ability alone increased significantly among the ADL functions. These findings indicate that the horse riding exercise may activate continuous muscular contraction, maintaining the tonus of the muscles. The continuous movement of horse riding could be lead to isometric muscle contraction in the lower limbs. These results suggest that the horse riding exercise develops muscle power and muscle reactions with exercise. Show more

Keywords: Horse riding, exercise effect, exercise instrument for indoor, the aged

DOI: 10.3233/BME-141054

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2407-2415, 2014

Authors: Yu, Chang Ho | Kwon, Tae Kyu

Article Type: Research Article

Abstract: The effect of stent design parameters such as porosity, pore density, number of strands, and strut angle to the artery were studied in vitro using particle image velocimetry (PIV). Five mesh stents were implanted into a sidewall aneurysm model. The flow features in a sidewall aneurysm silicone phantom model were investigated at a Reynolds number of 300. It was found that the lowest porosity stent had the best value for velocity and vorticity reduction in an aneurysm pocket. The stent with higher pore density had a tendency to decrease the mean and maximum velocities, but it was not superior to …the effects of porosity. In addition, investigation of the evaluation system confirmed that higher stent strut angles to the parent artery had a tendency to lower mean velocity, as shown by PIV and CFD. However, this effect was relatively smaller compared to porosity and pore density. Our evaluation system suggested the best combinations of parameters for the development of an ideal stent would be lower porosity, higher pore density, and higher strut angle. The results obtained in this study indicated that our evaluation system could be useful for various purposes related to evaluation of endovascular interventional devices. Show more

Keywords: Particle Image Velocimetry (PIV), stent, sidewall aneurysm, porosity, pore density

DOI: 10.3233/BME-141055

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2417-2424, 2014

Authors: Kang, Seung Rok | Yu, Chang Ho | Han, Kap Soo | Kwon, Tae Kyu

Article Type: Research Article

Abstract: The purpose of this study was to evaluate muscle function and basal physical fitness in relation to muscle balance pattern using rowing machines. Twenty four subjects participated in this study, using three different rowing machines. Rowing exercises were performed for twenty-five times a set, four sets a day, 3 days a week, for 8 weeks. Biodex system 3(Biodex Medical Systems Co., New York, USA) was used to measure joint torques in the elbow, shoulder, lumbar and knee of subjects, for analyzing muscle function. The evaluation of basal physical fitness included body composition, muscle strength, muscle endurance, muscle reaction, agility, flexibility …and explosive power. Before the experiment, significant differences of joint torques in the elbow, shoulder, lumbar and knee were present between subjects in the group. After the rowing exercise, significant improvement in every joint was witnessed. All aspects of basic fitness increased significantly, and the most improvement was observed in muscle strength from the joint torque results. As shown in the following results, every joint it was evident to have improved by more than 30% with the use of dependent load deviation type over the previously used water load method. This means that it is more effective for enhancing muscle strength and endurance to keep the muscle balance using dependent load deviation. The human body maintains motor coordination of muscle contraction during exercise. The muscle balances in the upper-lower and left-right arms could assist with effective activation of motor coordination. In this paper, an exercise method using dependent load deviation was demonstrated to be more efficient for improving muscle imbalance and strengthening muscles. Show more

Keywords: Muscle function, basal physical fitness, muscle balance pattern, rowing exercise

DOI: 10.3233/BME-141056

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2425-2435, 2014

Authors: Yu, Chang Ho | Kang, Seung Rok | Kwon, Tae Kyu

Article Type: Research Article

Abstract: This research was performed to assess the effects of angled whole body vibration on muscle activity of the lower limbs, by examining adults in their twenties during squat exercises, taking into account two variables of exercise intensity (vibration frequency and gradient). Twenty healthy males in their twenties with previous experience of more than 6 month's weight training and no past medical history were included in this study. The experiment was performed by participating in squat exercises which consisted of 3 sets (1 set = 5 seconds x 3 repetitions of exercise), and the muscle activities of the Rectus Femoris, Vastus …Lateralis, Vastus Medialis were measured with variation in the gradients of 0°, 10°, and 20°, and vibration frequencies of 20, 30, and 40 Hz. At 30 and 40 Hz, the vastus lateralis showed the highest change in muscle activity, while activity of the vastus medialis also increased significantly. Analysis of muscle activity according to the gradient showed a significant increase of the vastus lateralis at 20°, while the highest muscle activity at 20° was observed for the vastus medialis. In comparison of the change in lower limb muscle activity according to simultaneous stimulation, at a gradient of 10°, high activity was shown in muscle, while at 20°, high muscle activities were produced at 40 Hz in the vastus lateralis, 40 Hz in the rectus femoris, and both 30 and 40 Hz in the vastus medialis Show more

Keywords: Lower limb, muscle activity, exercise instrument for whole body vibration

DOI: 10.3233/BME-141057

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2437-2445, 2014

Authors: Son, Jongsang | Ryu, Jeseong | Kim, Jungyoon | Kim, Youngho

Article Type: Research Article

Abstract: In this study, a simple method based on the dynamic equation of motion was introduced to determine the moment of inertia using a commercial dynamometer, and an optimization technique was utilized to estimate inertial parameters with the determined moment of inertia. To evaluate the feasibility of the developed method, three different passive speeds (i.e. 240, 270 and 300°/s) were chosen to confirm whether the moment of inertia values are the same irrespective of angular speeds. Moreover, the estimated inertial parameters (i.e., the mass, center of mass and moment of inertia) of the elbow attachment and the disk-like 3 kg-weight were …compared with solutions of uniform square cube and solid disk, respectively. As a result, the values of moments of inertia of the elbow attachment were 0.216 ± 0.017, 0.215 ± 0.016 and 0.216 ± 0.017 kg·m2 at angular speeds of 240, 270 and 300°/s, respectively. The values of the moment of inertia of both the attachment and weight were 0.821 ± 0.054, 0.823 ± 0.058 and 0.824 ± 0.053 kg·m2 at angular speeds of 240, 270 and 300°/s, respectively. There were no significant differences among the speeds. The estimated inertial parameters of the attachment or the weight were very similar to the theoretical values. Therefore, it is expected that the developed method has the potential to estimate inertial parameters of a human body segment and to improve the accuracy and reliability of the studies on human dynamics. Show more

Keywords: Inertial parameters, mass, center of mass, radius of gyration, moment of inertia

DOI: 10.3233/BME-141058

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2447-2455, 2014

Authors: He, Wenbo | Wang, Yuan | Gong, Xiaoyan

Article Type: Research Article

Abstract: Generating an artificial blood flow in a circle system is an important step in hemodynamic research; thus, the influence of circle system components on the pulsatile flow wave forms should be investigated. In this study, a circle system was built, in which two solenoid valves were controlled by a timer to transform a constant flow into a pulsatile one, and two customized compliances with five different aeration volumes were set up upstream and downstream of the test chamber, achieving twenty-five different wave forms. Then, the influence of the compliance settings on the flow rate wave form was investigated. From the …experimental data, it can be concluded that the absolute value of the maximum value and the minimum value of the wave forms increases along the aeration of the downstream compliance but decreases along the aeration of the upstream compliance. For the second maximum value and the offset between the maximum value and the minimum value, remarkable differences were obtained between runs with aeration of zero compliance and nonzero compliance. Finally, an emulational flow was achieved with the up- and downstream aeration volume equaling 360mL and 180mL, respectively, which fit the realistic wave form well. Show more

Keywords: Pulsatile flow, compliance, particle image velocimetry, circle system, abdominal aortic aneurysms

DOI: 10.3233/BME-141059

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2457-2463, 2014

Authors: Zhu, Zhiwen | Zhang, Wendi | Xu, Jia

Article Type: Research Article

Abstract: A kind of shape memory alloy (SMA) hysteretic nonlinear model is developed, and the stochastic bifurcation characteristics of SMA intravascular stents subjected to radial and axial excitations are studied in this paper. A new nonlinear differential item is introduced to interpret the hysteretic phenomena of SMA strain-stress curves, and the dynamic model of SMA intravascular stent subjected to radial and axial stochastic excitations is established. The conditions of the system's stochastic stability are determined, and the probability density function of the system response is obtained. Finally, the stochastic Hopf bifurcation characteristics of the system are analyzed. Theoretical analysis and numerical …simulation show that the system stability varies with bifurcation parameters, and stochastic Hopf bifurcation occurs in the process; there are two limit cycles in the stationary probability density of the system response in some cases, which means that there are two vibration amplitudes whose probability are both very high; jumping phenomena between the two vibration amplitudes appears with the change of conditions, which may cause stent fracture or loss. The results of this paper are helpful for application of SMA intravascular stent in biomedical engineering fields. Show more

Keywords: Shape Memory Alloy (SMA), intravascular stent, stochastic load, global stability, stochastic bifurcation

DOI: 10.3233/BME-141060

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2465-2473, 2014

Authors: Yu, Chang Ho | Kang, Seung Rok | Jeong, Ho Choon | Kim, Kyung | Kwon, Tae Kyu

Article Type: Research Article

Abstract: This study was performed to assess the improvement of muscle strength imbalance in the lower limbs using a four point weight bearing reduction system with a two-belt treadmill. Participants, each having differences in muscle function of the left and right legs of over 20%, were divided into two groups of ten. The participants were involved in experiments progressing 40 minutes per day, 3 days per week, during a period of 4 weeks. The maximal peak torque and average power were measured for testing joint torque in the hip, knee and ankle. The results showed the improvement of muscle imbalance as …assessed by the maximal muscle strength was the most effective in the hip joint, while the improvement of muscular reaction was the most effective in the knee joint. We suggest that the method of weight bearing reduction could be sufficient to reduce muscle imbalance in the lower limbs. Show more

Keywords: Reduction of weight bearing, joint torque, gait, muscle imbalance, two-belt treadmill

DOI: 10.3233/BME-141061

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2475-2483, 2014

Authors: Seo, Jeong-Woo | Kang, Dong-Won | Kim, Ju-Young | Yang, Seung-Tae | Kim, Dae-Hyeok | Choi, Jin-Seung | Tack, Gye-Rae

Article Type: Research Article

Abstract: In this study, the accuracy of the inputs required for finite element analysis, which is mainly used for the biomechanical analysis of bones, was improved. To ensure a muscle force and joint contact force similar to the actual values, a musculoskeletal model that was based on the actual gait experiment was used. Gait data were obtained from a healthy male adult aged 29 who had no history of musculoskeletal disease and walked normally (171cm height and 72kg weight), and were used as inputs for the musculoskeletal model simulation to determine the muscle force and joint contact force. Among the phases …of gait, which is the most common activity in daily life, the stance phase is the most affected by the load. The results data were extracted from five events in the stance phase: heel contact (ST1), loading response (ST2), early mid-stance (ST2), late mid-stance (ST4), and terminal stance (ST5). The results were used as the inputs for the finite element model that was formed using 1.5mm intervals computed tomography (CT) images and the maximum Von-Mises stress and the maximum Von-Mises strain of the right femur were examined. The maximum stress and strain were lowest at the ST4. The maximum values for the femur occurred in the medial part and then in the lateral part after the mid-stance. In this study, the results of the musculoskeletal model simulation using the inverse-dynamic analysis were utilized to improve the accuracy of the inputs, which affected the finite element analysis results, and the possibility of the bone-specific analysis according to the lapse of time was examined. Show more

Keywords: Musculoskeletal modeling, finite element analysis, inverse dynamics

DOI: 10.3233/BME-141062

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2485-2493, 2014

Authors: Chen, Duanduan | Zhong, Yi | Shinohara, Kyosuke | Nishida, Tomoki | Hasegawa, Toshiaki | Hamada, Hiroshi

Article Type: Research Article

Abstract: The cilia, presenting a rotational movement in the embryonic nodes, play a crucial role in the left-right specification during embryogenesis. The characteristic architecture of these cilia is based on a cylindrical arrangement of 9 doublet microtubules and the motion of the cilia is triggered by the dynein motors located between adjacent doublets by converting the chemical energy into mechanical work. Restricted by the inherent difficulties of experiments, the dynein activation patterns in moving cilia cannot be directly observed. Thus, the mechanism of nodal ciliary movement is still unclear. In this study, we present computational models of the nodal ciliary ultrastructure …based on tomographic images of the ciliary body. By employing time accurate three-dimensional solid mechanics analysis, we investigate the dynein-triggered sliding between adjacent doublet microtubules and simulate the induced ciliary bending. As an exploratory study, two dynein activation patterns are proposed and their rationality is discussed. The mathematical model presented by this paper provides a platform to investigate various assumptions of dynein activity, facilitating us to propose the most possible dynein activation pattern and therefore improving our understandings regarding the protein-beating problems of cilia. Show more

Keywords: Cilia, dynein, ultrastructure, embryonic node, finite element analysis

DOI: 10.3233/BME-141063

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2495-2501, 2014

Authors: Shin, Dong Ho | Lim, Hyung-Gyu | Jung, Eui Sung | Wei, Qun | Seong, Ki Woong | Lee, Jyung Hyun | Lee, Seung-ha | Cho, Jin Ho

Article Type: Research Article

Abstract: Since the 1980's, various types of implantable hearing aids using unique means for delivering acoustic power to the inner ear have been developed. Recently, implantable hearing aids that stimulate the round window by the middle ear transducer have received great attention because it reduces loading effect at the ossicular chain. In this study, we have implemented a direct install 3-pole type EM transducer in round window niche for implantable middle ear hearing aid. The 3-pole type EM transducer consists of two permanent magnets and three coils and exhibit structural features that minimize leakage flux, thereby permitting high efficiency and low …magnetic field interference. The stapes velocity was measured using a laser Doppler vibrometer in response to the round window stimulation from the transducer. To verify the usefulness of the 3-pole type EM transducer, we compared the stapes vibration characteristics produced by the transducer and those from a sound source. The magnitude of stapes velocity due to the round window stimulation at 1 mArms was equivalent to that of stapes velocity at 94 dB SPL sound stimulation. Thus, the evaluation study shows that the 3-pole type EM transducer is suitable for implantable hearing devices. Show more

Keywords: 3-pole type EM transducer, round window, stapes velocity, implantable hearing aids

DOI: 10.3233/BME-141064

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2503-2510, 2014

Authors: Wang, Tong | Xing, Zhongwen

Article Type: Research Article

Abstract: This paper presents a fluid-particle interaction algorithm using the distributed Lagrange multiplier based fictitious domain method. The application of this method to the numerical investigation of motion and aggregation of red blood cells in two-dimensional microvessels is discussed. The cells are modelled as rigid biconcave-shaped neutrally buoyant particles. The aggregating force between two cells is derived from a Morse type potential function. The cell-cell interaction is coupled with the fluid-cell interaction through a time splitting scheme. Simulation results of multiple red blood cells in Poiseuille flow are presented. Because of its modular nature, this algorithm is applicable to a large …class of problems involving the processes of particle aggregation and fluid-particle interaction. Show more

Keywords: Fluid-particle interaction, red blood cells, aggregation, mathematical modelling

DOI: 10.3233/BME-141065

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2511-2517, 2014

Authors: Veshkina, Natalia | Zbicinski, Ireneusz | Stefańczyk, Ludomir

Article Type: Research Article

Abstract: In this study, a fluid-structure interaction analysis based on the application of patient-specific mechanical parameters of the aneurismal walls was carried out to predict the rupture side during an abdominal aortic aneurysm (AAA). Realistic geometry of the aneurysm was reconstructed from CT data acquired from the patient, and patient-specific flow conditions were applied as boundary conditions. A newly developed non-invasive methodology for determining the mechanical parameters of the patient-specific aortic wall was employed to simulate realistic aortic wall behaviors. Analysis of the results included time-averaged wall shear stress (TAWSS), oscillatory shear index (OSI), and von Mises stress (VMS). Results of …the TAWSS, OSI, and VMS were compared to identify the most probable region of the AAA's rupture. High OSI, which identified the region of wall degradation, coincided with the location of maximum VMS, meaning that the anterior part of the aneurismal wall was a potential region of rupture. Show more

Keywords: Fluid-structure interaction, abdominal aortic aneurysm, mechanical parameters of the aortic wall, computed tomography, computational fluid dynamics

DOI: 10.3233/BME-141066

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2519-2526, 2014

Authors: Chen, Yanyan | Li, Ge | Zhu, Yanhe | Zhao, Jie | Cai, Hegao

Article Type: Research Article

Abstract: In this paper, a 6-DOF wearable upper limb exoskeleton with parallel actuated joints which perfectly mimics human motions is proposed. The upper limb exoskeleton assists the movement of physically weak people. Compared with the existing upper limb exoskeletons which are mostly designed using a serial structure with large movement space but small stiffness and poor wearable ability, a prototype for motion assistance based on human anatomy structure has been developed in our design. Moreover, the design adopts balls instead of bearings to save space, which simplifies the structure and reduces the cost of the mechanism. The proposed design also employs …deceleration processes to ensure that the transmission ratio of each joint is coincident. Show more

Keywords: Upper limb, parallel actuated joints, exoskeleton, rehabilitation

DOI: 10.3233/BME-141067

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2527-2535, 2014

Authors: Han, Kap Soo | Shin, Sun Hye | Yu, Chang Ho | Kwon, Tae Kyu

Article Type: Research Article

Abstract: This study investigated the characteristics of dynamic postural responses when subjects attempted to maintain an upright standing position on a support plate during continuous sinusoidal perturbation in the anterior-posterior direction. Fifteen healthy young subjects participated in the experiment. Body movement patterns during the perturbation were captured and analyzed using a 3D motion analysis system (APAS 3D motion analysis, Ariel Dynamics Inc.). Seven markers were attached on the subject's body to measure and analyze the motion patterns. The markers were positioned at the head, chest, hip, right knee, left knee, right ankle, and left ankle. Five different frequencies of motion were …applied to the support surface: 0.1, 0.5, 1.0, 1.5, and 2.0 Hz with a 4-cm path of motion at the base. The experiments measured dynamic postural responses in a condition were subjects had their eyes open. The results showed that the median frequency of the knee and ankle increased in all frequency bands. Following an increase in the frequency of the perturbation, the postural control strategy was changed from the ankle strategy to a combined strategy. These experimental results could be applied to the dynamic postural training for the elderly and to rehabilitation training for patients to improve their ability for postural control. Show more

Keywords: Postural control, dynamic postural balance, motion base, horizontal translation

DOI: 10.3233/BME-141068

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2537-2545, 2014

Authors: Ma, Jingtao | Xu, Yuanqing | Tian, Fangbao | Tang, Xiaoying

Article Type: Research Article

Abstract: Separation of two categories of cells in pinched flow fractionation(PFF) device is simulated by employing IB-LBM. The separation performances at low Reynolds number (about 1) under different pinched segment widths, flow ratios, cell features, and distances between neighboring cells are studied and the results are compared with those predicted by the empirical formula. The simulation indicates that the diluent flow rate should approximate to or more than the flow rate of particle solution in order to get a relatively ideal separation performance. The discrepancy of outflow position between numerical simulation and the empirical prediction enlarges, when the cells become more …flexible. Too short distance between two neighboring cells could lead to cell banding which would result in incomplete separation, and the relative position of two neighboring cells influences the banding of cells. The present study will probably provide some new applications of PFF, and make some suggestions on the design of PFF devices. Show more

Keywords: IB-LBM, pinched ow fractionation, cell separation

DOI: 10.3233/BME-141069

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2547-2554, 2014

Authors: Chen, Baoming | Song, Tianyi | Guo, Tao | Xiang, Haiyan | Liu, Yanyong | Qin, Yufei | Cao, Zhengtao | Yu, Mengsun

Article Type: Research Article

Abstract: Non-invasive pressure simulators that regenerate oscillometric waveforms promise an alternative to expensive clinical trials for validating oscillometric noninvasive blood pressure devices. However, existing simulators only provide oscillometric pressure in cuff and thus have a limited accuracy. It is promising to build a physical simulator that contains a synthetic arm with a built-in brachial artery and an affiliated hydraulic model of cardiovascular system. To guide the construction of this kind of simulator, this paper presents a computer model of cardiovascular system with a relatively simple structure, where the distribution of pressures and flows in aorta root and brachial artery can be …simulated, and the produced waves are accordant with the physical data. This model can be used to provide the parameters and structure that will be needed to build the new simulator. Show more

Keywords: Computer model, cardiovascular system, brachial artery, non-invasive pressure simulator

DOI: 10.3233/BME-141070

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2555-2561, 2014

Authors: Magdás, Annamária | Szilágyi, László | Belényi, Boglárka | Incze, Alexandru

Article Type: Research Article

Abstract: Hypertension in the elderly is characterized by isolated systolic hypertension and high variability, but its clinical significance is not yet fully understood. The goal of this paper was to assess circadian blood pressure variability (BPV) in elderly hypertensives, and to determine its relationship to cardiovascular risk factors. To achieve this goal, a number of 75 inefficiently treated hypertensive patients were studied, 45 elderly, aged over 60 years, 30 middle-aged, younger than 60 years. After 24-hour ambulatory blood pressure monitoring (ABPM), blood pressure (BP) values, pulse pressure (PP), morning surge were compared between the groups. BPV was calculated using average real …variability (ARV). The relationships between BPV, pulse pressure, left ventricular mass index (LVMI), and cardiovascular risk factors were assessed in both groups. As a result, it was found that left ventricular mass (p=0.01), PP, morning surge, 24-hour systolic ARV were significantly higher in the elderly group (p<0.05). In both groups, higher 24-hour BPV was associated with an increase in LVMI. In the elderly population 24-hour BPV was positively correlated to increased PP, total cholesterol and triglyceride levels (p<0.05). Moreover, it was concluded that ABPM-derived BP variability index could be an early predictive marker of end-organ damage in hypertension. Its reduction might be an important objective of hypertension management in elderly. Show more

Keywords: ABPM, blood pressure variability, cardiovascular risk factors, elderly

DOI: 10.3233/BME-141071

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2563-2569, 2014

Authors: Xiao, Jinzhuang | Gao, Junmin | Wang, Hongrui | Yang, Xincai

Article Type: Research Article

Abstract: More and more people suffer from lumbar muscle strain due to lack of exercise. Cycling serves as both a stylish model of fitness and a training method in exercise and rehabilitation. A few of previous studies have examined the changes in lower extremity muscle activities during indoor cycling, but fewer data pertain to the low back muscles. This study aims to analyze the functional status of erector spinae during cycling by learning the regularity and characteristics of changes in sEMG frequency domain index-mean frequency (MF) within ten minutes. The statistical results showed that the values of 70% subjects fluctuated within …the range of (0.04688±0.00125) Hz within the first 30 s and the values raised rapidly to the (150±10) Hz range after the 30 s. Moreover, the values trended to decline slowly in a fluctuating way after a while. However, no obvious regularity was observed among the remaining 30% of the subjects. Results of this study demonstrated that the muscle fatigue with a smaller level of low back began to emerge gradually after 30 s. Moreover, it is evident that cycling can be an incentive to the low back muscles in most people. Show more

Keywords: Cycling, sEMG, MF, erector spinae, muscle fatigue

DOI: 10.3233/BME-141072

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2571-2576, 2014

Authors: Zhang, Junxia | Si, Ying | Zhang, Yan | Liu, Yefang

Article Type: Research Article

Abstract: The first metatarsophalangeal (MTP) joint is a critical component for normal walking. The present study aimed to investigate the effects of restricting the flexion-extension motion of the first MTP joint on human walking gait. Ten male participants were recruited to perform walking trials under barefoot (BF) and the first MTP joint constraint (FMJC) conditions, respectively. The results showed that there were statistically significant differences in walking speed and stride length. The characteristics of angular displacement in three lower limb joints and ground reaction force (GRF) were almost identical in BF and FMJC. However, maxima, minima and range of motion of …three joint angles were significantly different. The utilized coefficient of friction (UCOF) increased significantly after FMJC, indicating that there may be a greater risk of slippage and falling when FMJC. Show more

Keywords: The first metatarsophalangeal joint, constraint, gait analysis

DOI: 10.3233/BME-141073

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2577-2584, 2014

Authors: Zhang, Yang | Wang, Yuan | He, Wenbo | Yang, Bin

Article Type: Research Article

Abstract: A novel Particle Tracking Velocimetry (PTV) algorithm based on Voronoi Diagram (VD) is proposed and briefed as VD–PTV. The robustness of VD–PTV for pulsatile flow is verified through a test that includes a widely used artificial flow and a classic reference algorithm. The proposed algorithm is then applied to visualize the flow in an artificial abdominal aortic aneurysm included in a pulsatile circulation system that simulates the aortic blood flow in human body. Results show that, large particles tend to gather at the upstream boundary because of the backflow eddies that follow the pulsation. This qualitative description, together with VD–PTV, …has laid a foundation for future works that demand high-level quantification. Show more

Keywords: Particle tracking velocimetry, Voronoi diagram, aortic blood flow, abdominal aortic aneurysm, pulsatile circulation system

DOI: 10.3233/BME-141074

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2585-2591, 2014

Authors: Sui, Jianfeng | Shull, Pete | Ji, Linhong

Article Type: Research Article

Abstract: Robot-assisted therapy has been proved effective for dyskinesia, and has many unique advantages compared with traditional treatment, such as repeatability, accuracy, objectivity. But some studies show that the effect of the robot-assisted rehabilitation for improving patients' activities of daily life (ADLs) is not obvious. This study introduces a novel auxiliary method-vibration stimulation combined with robots which may improve patients' ADLs. In controlled trials, two kinds of feedback-vibration and visual feedback are applied to prompt subjects for rehabilitation, and electromyographic signals (EMGs) and motion parameters are recorded in real time. Experimental results show that subjects' EMGs using vibration feedback are similar …to healthy people, and characteristics of motion are closer to the theoretical value compared with control group. Vibration stimulation may serve as a kind of efficient auxiliary means to improve the efficiency of neurological rehabilitation. Show more

Keywords: Vibration stimulation, neurological rehabilitation, neuroplasticity, rehabilitation robot

DOI: 10.3233/BME-141075

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2593-2601, 2014

Authors: Park, Ji H. | Shurtleff, Timothy | Engsberg, Jack | Rafferty, Sandy | You, Joshua Y. | You, Isaac Y. | You, Sung H.

Article Type: Research Article

Abstract: While the novel robotic hippotherapy system has gradually gained clinical application for therapeutic intervention on postural and locomotor control in individuals with neurological or musculoskeletal impairments, the system's validity and reliability for the robotic hippotherapy system has not been well established. The objective of the current study was to investigate the validity and test-retest reliability of the robotic hippotherapy system by comparing with real horse movements. The 3-axis accelerometer sensors attached on the robotic and real horse saddles were used to collect 3-dimensional acceleration data at a preferred walking velocity. Linear regression analysis showed an excellent correlation in the time-to-peak …acceleration (TPA) (R2 =0.997), but little correlation in X-axis acceleration between the real and robotic horses (R2 =0.177), thus confirming consistent time control and a certain degree of variability between the robotic and real horse movements. The mean resultant accelerations for a real horse and robotic horse were 3.22 m/s2 and 0.67 m/s2 , respectively, accounting for almost five times greater acceleration in the real horse than the robotic horse. Show more

Keywords: Robotic hippotherapy, acceleration

DOI: 10.3233/BME-141076

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2603-2610, 2014