Pub Date : 2015-02-26DOI: 10.1504/IJECB.2015.067679
B. Fallqvist, A. Kulachenko, M. Kroon
The actin cytoskeleton is essential for the continued function and survival of the cell. A peculiar mechanical characteristic of actin networks is their remodelling ability, providing them with a time-dependent response to mechanical forces. In cross-linked actin networks, this behaviour is typically tuned by the binding affinity of the cross-link. We propose that the debonding of a cross-link between filaments can be modelled using a stochastic approach, in which the activation energy for a bond is modified by a term to account for mechanical strain energy. By use of a finite element model, we perform numerical analyses in which we first compare the model behaviour to experimental results. The computed and experimental results are in good agreement for short time scales, but over longer time scales the stress is overestimated. However, it does provide a possible explanation for experimentally observed strain-rate dependence as well as strain-softening at longer time scales.
{"title":"Cross-link debonding in actin networks : influence on mechanical properties","authors":"B. Fallqvist, A. Kulachenko, M. Kroon","doi":"10.1504/IJECB.2015.067679","DOIUrl":"https://doi.org/10.1504/IJECB.2015.067679","url":null,"abstract":"The actin cytoskeleton is essential for the continued function and survival of the cell. A peculiar mechanical characteristic of actin networks is their remodelling ability, providing them with a time-dependent response to mechanical forces. In cross-linked actin networks, this behaviour is typically tuned by the binding affinity of the cross-link. We propose that the debonding of a cross-link between filaments can be modelled using a stochastic approach, in which the activation energy for a bond is modified by a term to account for mechanical strain energy. By use of a finite element model, we perform numerical analyses in which we first compare the model behaviour to experimental results. The computed and experimental results are in good agreement for short time scales, but over longer time scales the stress is overestimated. However, it does provide a possible explanation for experimentally observed strain-rate dependence as well as strain-softening at longer time scales.","PeriodicalId":90184,"journal":{"name":"International journal of experimental and computational biomechanics","volume":"3 1","pages":"16-26"},"PeriodicalIF":0.0,"publicationDate":"2015-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1504/IJECB.2015.067679","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66745235","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-02-26DOI: 10.1504/IJECB.2015.067681
Ahmad Chitsazan, G. Rouhi, M. Abbasi, Saeid Pezeshki, S. A. Tavakoli
The goal of this study was to determine stress distribution in ankle joint by correlating with the strain distribution and its trend around tibia adjacent to the joint. Using an in-house device, an ankle from a cadaver was kept stable and loaded in various positions: neutral, dorsiflexion, plantar flexion, inversion and eversion. A total of six strain gauges were mounted around the shaft of the tibia, near the tibiotalar joint. This arrangement allowed us to measure deformations in the shaft of tibia. Patient-specific ankle joint geometry was generated from computed tomography data. The finite element model (FEM) of the ankle was validated using the experimental data logged by the strain gauges, and used for obtaining stress on the joint surface. A strong correlation was observed between the FEM and experimentally measured strains in magnitude (R = 0.94, P = 0.008), consequently stress distribution over the joint surface was obtained.
本研究的目的是通过与关节附近胫骨周围的应变分布及其趋势的相关性来确定踝关节的应力分布。使用内部装置，尸体脚踝保持稳定，并在不同位置加载:中性、背屈、足底屈、内翻和外翻。在胫骨轴周围，靠近胫距关节处，总共安装了6个应变片。这种安排使我们能够测量胫骨轴的变形。根据计算机断层扫描数据生成患者特定的踝关节几何形状。利用应变仪记录的实验数据对踝关节有限元模型进行了验证，并用于获取关节表面的应力。结果表明，有限元法计算的应变值与实验测量的应变值具有较强的相关性(R = 0.94, P = 0.008)，从而得到了节理表面的应力分布。
{"title":"Assessment of stress distribution in ankle joint: simultaneous application of experimental and finite element methods","authors":"Ahmad Chitsazan, G. Rouhi, M. Abbasi, Saeid Pezeshki, S. A. Tavakoli","doi":"10.1504/IJECB.2015.067681","DOIUrl":"https://doi.org/10.1504/IJECB.2015.067681","url":null,"abstract":"The goal of this study was to determine stress distribution in ankle joint by correlating with the strain distribution and its trend around tibia adjacent to the joint. Using an in-house device, an ankle from a cadaver was kept stable and loaded in various positions: neutral, dorsiflexion, plantar flexion, inversion and eversion. A total of six strain gauges were mounted around the shaft of the tibia, near the tibiotalar joint. This arrangement allowed us to measure deformations in the shaft of tibia. Patient-specific ankle joint geometry was generated from computed tomography data. The finite element model (FEM) of the ankle was validated using the experimental data logged by the strain gauges, and used for obtaining stress on the joint surface. A strong correlation was observed between the FEM and experimentally measured strains in magnitude (R = 0.94, P = 0.008), consequently stress distribution over the joint surface was obtained.","PeriodicalId":90184,"journal":{"name":"International journal of experimental and computational biomechanics","volume":"3 1","pages":"45"},"PeriodicalIF":0.0,"publicationDate":"2015-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1504/IJECB.2015.067681","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66745297","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-02-26DOI: 10.1504/IJECB.2015.067680
Xuelin Wang, Don U. Nakmali, R. Gan
To better reveal the mechanical properties of round window membrane (RWM) in normal and pathological ears, the complex modulus of chinchilla RWM was determined by measuring its dynamic behaviour together with the finite element simulation. The acute otitis media (AOM) was created by transbullar injection of Haemophilus influenzae in chinchillas and RWM specimens in AOM ears were prepared four days post inoculation. Vibration of the RWM induced by coil-magnet force stimulation was measured by laser Doppler vibrometry over frequencies of 0.2–8 kHz. A finite element model-based inverse-problem solving method was used to determine the complex modulus of each RWM specimen in the frequency domain. Experimental results of the AOM ears indicated that the resonance frequency decreased by 13.94% compared with the normal ears and the mean storage modulus and loss modulus were decreased by 65% and 32%, respectively.
{"title":"Complex modulus of round window membrane over auditory frequencies in normal and otitis media chinchilla ears","authors":"Xuelin Wang, Don U. Nakmali, R. Gan","doi":"10.1504/IJECB.2015.067680","DOIUrl":"https://doi.org/10.1504/IJECB.2015.067680","url":null,"abstract":"To better reveal the mechanical properties of round window membrane (RWM) in normal and pathological ears, the complex modulus of chinchilla RWM was determined by measuring its dynamic behaviour together with the finite element simulation. The acute otitis media (AOM) was created by transbullar injection of Haemophilus influenzae in chinchillas and RWM specimens in AOM ears were prepared four days post inoculation. Vibration of the RWM induced by coil-magnet force stimulation was measured by laser Doppler vibrometry over frequencies of 0.2–8 kHz. A finite element model-based inverse-problem solving method was used to determine the complex modulus of each RWM specimen in the frequency domain. Experimental results of the AOM ears indicated that the resonance frequency decreased by 13.94% compared with the normal ears and the mean storage modulus and loss modulus were decreased by 65% and 32%, respectively.","PeriodicalId":90184,"journal":{"name":"International journal of experimental and computational biomechanics","volume":"3 1","pages":"27"},"PeriodicalIF":0.0,"publicationDate":"2015-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1504/IJECB.2015.067680","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66745250","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-02-26DOI: 10.1504/IJECB.2015.067678
Kimberly Szucs, J. Borstad
Despite conclusions from previous research that clavicle rotation is necessary for normal shoulder motion, dynamic clavicle rotations are rarely included in shoulder studies. This is likely due to the difficult nature in capturing clavicle motion. The purpose of this study was to determine the validity of non-invasive electromagnetic measures of dynamic clavicle motion against bone pin measurements. 3D rotations of the clavicle were collected simultaneously from a surface sensor and bone pin mounted sensor from six cadaveric shoulders. Intraclass correlation coefficients (ICCs) were calculated to determine the validity of the surface sensor measurements compared to the bone pin measurements. It was determined that the electromagnetic surface sensor accurately tracks retraction and elevation, but underestimates axial rotation. A mathematical equation was developed to improve the fit of surface sensor values for axial rotation. The strong ICC values for each clavicle rotation suggest that the surface sensor...
{"title":"Capturing three-dimensional clavicle kinematics: a validation of surface sensor measurements","authors":"Kimberly Szucs, J. Borstad","doi":"10.1504/IJECB.2015.067678","DOIUrl":"https://doi.org/10.1504/IJECB.2015.067678","url":null,"abstract":"Despite conclusions from previous research that clavicle rotation is necessary for normal shoulder motion, dynamic clavicle rotations are rarely included in shoulder studies. This is likely due to the difficult nature in capturing clavicle motion. The purpose of this study was to determine the validity of non-invasive electromagnetic measures of dynamic clavicle motion against bone pin measurements. 3D rotations of the clavicle were collected simultaneously from a surface sensor and bone pin mounted sensor from six cadaveric shoulders. Intraclass correlation coefficients (ICCs) were calculated to determine the validity of the surface sensor measurements compared to the bone pin measurements. It was determined that the electromagnetic surface sensor accurately tracks retraction and elevation, but underestimates axial rotation. A mathematical equation was developed to improve the fit of surface sensor values for axial rotation. The strong ICC values for each clavicle rotation suggest that the surface sensor...","PeriodicalId":90184,"journal":{"name":"International journal of experimental and computational biomechanics","volume":"3 1","pages":"1"},"PeriodicalIF":0.0,"publicationDate":"2015-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1504/IJECB.2015.067678","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66745225","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-12-03DOI: 10.1504/IJECB.2014.066081
B. Terry, Xin Wang, J. Schoen, M. Rentschler
Understanding the biomechanical properties of the small intestine is necessary for developing in vivo mobility systems for miniature robots. In this work, we have experimentally determined preconditioning parameters and then performed in-plane biaxial biomechanical characterisation of small intestinal tissue. Excised tissue samples underwent uniaxial tension tests for two physiological Piola-stress values and multiple cycles. The percent change in the length of the tissue reached equilibrium after approximately 13 preconditioning cycles for both loading values. The mechanical behaviour of the tissue did not appear to be affected by the loading values. Thirty-three tissue samples from the proximal, middle, and distal regions of the small intestine of three pigs underwent preconditioning and subsequent in-plane biaxial biomechanical characterisation. The mean moduli for all samples in the low and high modulus regions were, respectively, 307.25 ± 29.67 kPa and 2,211.72 ± 316.88 kPa along the longitudinal dir...
{"title":"A preconditioning protocol and biaxial mechanical measurement of the small intestine","authors":"B. Terry, Xin Wang, J. Schoen, M. Rentschler","doi":"10.1504/IJECB.2014.066081","DOIUrl":"https://doi.org/10.1504/IJECB.2014.066081","url":null,"abstract":"Understanding the biomechanical properties of the small intestine is necessary for developing in vivo mobility systems for miniature robots. In this work, we have experimentally determined preconditioning parameters and then performed in-plane biaxial biomechanical characterisation of small intestinal tissue. Excised tissue samples underwent uniaxial tension tests for two physiological Piola-stress values and multiple cycles. The percent change in the length of the tissue reached equilibrium after approximately 13 preconditioning cycles for both loading values. The mechanical behaviour of the tissue did not appear to be affected by the loading values. Thirty-three tissue samples from the proximal, middle, and distal regions of the small intestine of three pigs underwent preconditioning and subsequent in-plane biaxial biomechanical characterisation. The mean moduli for all samples in the low and high modulus regions were, respectively, 307.25 ± 29.67 kPa and 2,211.72 ± 316.88 kPa along the longitudinal dir...","PeriodicalId":90184,"journal":{"name":"International journal of experimental and computational biomechanics","volume":"2 1","pages":"293"},"PeriodicalIF":0.0,"publicationDate":"2014-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1504/IJECB.2014.066081","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66745097","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-12-03DOI: 10.1504/IJECB.2014.066086
Gustav Lindberg, A. Shokry, W. Reheman, I. Svensson
Measuring the diffusivity of various substances in cortical bone is in general difficult. For instance, making use of micro computed tomography requires agents that can be separated from bone, blood and other substances that exist in cortical bone. Here a more easily accessible method is presented. A series of cortical bovine bone samples were put in a saturated solution of potassium chloride for a time period that was long enough for the samples to be regarded as saturated. The samples were removed from the solution and moulded in polyester leaving only the radial directions open. In the next step, the bone samples were put in distilled water and the conductivity of the water was registered over time. An analytical model fulfilling Ficks law was introduced and by means of Kalman filtering an estimation for the diffusion coefficient of potassium chloride in bovine bone is presented.
{"title":"Determination of diffusion coefficients in bovine bone by means of conductivity measurement","authors":"Gustav Lindberg, A. Shokry, W. Reheman, I. Svensson","doi":"10.1504/IJECB.2014.066086","DOIUrl":"https://doi.org/10.1504/IJECB.2014.066086","url":null,"abstract":"Measuring the diffusivity of various substances in cortical bone is in general difficult. For instance, making use of micro computed tomography requires agents that can be separated from bone, blood and other substances that exist in cortical bone. Here a more easily accessible method is presented. A series of cortical bovine bone samples were put in a saturated solution of potassium chloride for a time period that was long enough for the samples to be regarded as saturated. The samples were removed from the solution and moulded in polyester leaving only the radial directions open. In the next step, the bone samples were put in distilled water and the conductivity of the water was registered over time. An analytical model fulfilling Ficks law was introduced and by means of Kalman filtering an estimation for the diffusion coefficient of potassium chloride in bovine bone is presented.","PeriodicalId":90184,"journal":{"name":"International journal of experimental and computational biomechanics","volume":"2 1","pages":"324-342"},"PeriodicalIF":0.0,"publicationDate":"2014-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1504/IJECB.2014.066086","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66745146","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-12-03DOI: 10.1504/IJECB.2014.066090
D. B. Coelho, M. Duarte
The way humans control the balance in the upright posture is not yet fully understood and complications due to deficiency in the postural control are of relevant concern. In order to achieve an early diagnosis on disorders affecting human postural control, the theoretical modelling coupled with computer simulation emerges as an option used by researchers. Looking for a model for a greater understanding of human postural control system, this paper presents a new computational model dedicated to the study of human upright posture, with the presentation of a model of muscle-tendon actuator. The way in which the subsystems of human control, such as the dynamic muscle, neural control, visual, vestibular and somatosensory contribute to the stable posture was also focused. This model simulate the responses of fluctuations in the centre of mass and centre of pressure and offers the possibility of measuring neural activation, decomposition of reactive torque and participation of each set of muscle groups to maintain posture. It reproduces, in a model of feedback, the existing cross-correlation between experimentally observed and the neural signal and the centre of pressure.
{"title":"Human postural control during standing posture with a muscle-tendon actuator","authors":"D. B. Coelho, M. Duarte","doi":"10.1504/IJECB.2014.066090","DOIUrl":"https://doi.org/10.1504/IJECB.2014.066090","url":null,"abstract":"The way humans control the balance in the upright posture is not yet fully understood and complications due to deficiency in the postural control are of relevant concern. In order to achieve an early diagnosis on disorders affecting human postural control, the theoretical modelling coupled with computer simulation emerges as an option used by researchers. Looking for a model for a greater understanding of human postural control system, this paper presents a new computational model dedicated to the study of human upright posture, with the presentation of a model of muscle-tendon actuator. The way in which the subsystems of human control, such as the dynamic muscle, neural control, visual, vestibular and somatosensory contribute to the stable posture was also focused. This model simulate the responses of fluctuations in the centre of mass and centre of pressure and offers the possibility of measuring neural activation, decomposition of reactive torque and participation of each set of muscle groups to maintain posture. It reproduces, in a model of feedback, the existing cross-correlation between experimentally observed and the neural signal and the centre of pressure.","PeriodicalId":90184,"journal":{"name":"International journal of experimental and computational biomechanics","volume":"187 1","pages":"343"},"PeriodicalIF":0.0,"publicationDate":"2014-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1504/IJECB.2014.066090","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66745157","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-12-03DOI: 10.1504/IJECB.2014.066091
Y. Hsu, C. Lupton, J. Tong, A. Cossey, A. Au
Loading from daily activities or from intensive exercise can lead to increased risk of fracture. Implants designed for load bearing purposes, such as repair of articular cartilage and underlying subchondral bone in knees must have the necessary mechanical competence under long term physiological loadings. In this study, the mechanical behaviour of a polymer-based osteochondral scaffold was examined under monotonic and cyclic loading conditions in a phosphate buffered saline solution at 37°C. Monotonic compression tests at selected strain rates were performed in both confined and unconfined conditions to investigate the influence of confinement. The effects of strain rate and sample composition on mechanical properties were also studied. Multi-step cyclic tests were carried out with increasing compressive loads. Changes in secant modulus and residual strain accumulation are monitored. The secant modulus and the number of cycles to failure of the scaffold are obtained and compared with those of human trabecular bone (Topolinski et al., 2011).
日常活动或剧烈运动带来的负荷会增加骨折的风险。为承载目的而设计的植入物，如膝关节关节软骨和软骨下骨的修复，必须在长期生理负荷下具有必要的机械能力。在这项研究中，在37°C的磷酸盐缓冲盐水溶液中，研究了聚合物基骨软骨支架在单调和循环加载条件下的力学行为。在选定的应变速率下进行了密闭和非密闭条件下的单调压缩试验，以研究约束的影响。研究了应变速率和试样成分对材料力学性能的影响。随着压缩载荷的增加，进行了多步循环试验。割线模量和残余应变积累的变化被监测。获得了支架的割线模量和失效循环次数，并与人小梁骨进行了比较(Topolinski et al.， 2011)。
{"title":"Mechanical characterisation of a scaffold under monotonic and cyclic loading conditions","authors":"Y. Hsu, C. Lupton, J. Tong, A. Cossey, A. Au","doi":"10.1504/IJECB.2014.066091","DOIUrl":"https://doi.org/10.1504/IJECB.2014.066091","url":null,"abstract":"Loading from daily activities or from intensive exercise can lead to increased risk of fracture. Implants designed for load bearing purposes, such as repair of articular cartilage and underlying subchondral bone in knees must have the necessary mechanical competence under long term physiological loadings. In this study, the mechanical behaviour of a polymer-based osteochondral scaffold was examined under monotonic and cyclic loading conditions in a phosphate buffered saline solution at 37°C. Monotonic compression tests at selected strain rates were performed in both confined and unconfined conditions to investigate the influence of confinement. The effects of strain rate and sample composition on mechanical properties were also studied. Multi-step cyclic tests were carried out with increasing compressive loads. Changes in secant modulus and residual strain accumulation are monitored. The secant modulus and the number of cycles to failure of the scaffold are obtained and compared with those of human trabecular bone (Topolinski et al., 2011).","PeriodicalId":90184,"journal":{"name":"International journal of experimental and computational biomechanics","volume":"2 1","pages":"359-375"},"PeriodicalIF":0.0,"publicationDate":"2014-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1504/IJECB.2014.066091","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66745166","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-04-14DOI: 10.1504/IJECB.2014.060402
A. Al-Fahoum, Khaled Gharaibeh
A novel alternative method reducing the need for direct inverse dynamics to solve the muscle redundancy problem at human lower limbs is proposed. It aims at computing lower limb joints moments under dynamic conditions using only electromyographic (EMG) signals in combination with an auto regressive moving average (ARMA) model. The experimental protocol is conducted by practicing full gait cycle trials in an effort to calculate joint moments. Quantitative comparisons with the output of a biological-based model showed that the proposed method is able to: 1) produce accurate estimates of the resultant moment; 2) maintain the obtained accuracy regardless of the information about status of the angle or its derivatives. The joint moment prediction by the ARMA model attained an average of R2 = 1.73. The model is characterised by stability, accuracy and minimum number of input variables. These characteristics represent an added value to be utilised in lower limbs rehabilitation.
{"title":"Prediction of sagittal lower limb joints moments under dynamic condition: feasibility of using EMG and ARMA model identification techniques","authors":"A. Al-Fahoum, Khaled Gharaibeh","doi":"10.1504/IJECB.2014.060402","DOIUrl":"https://doi.org/10.1504/IJECB.2014.060402","url":null,"abstract":"A novel alternative method reducing the need for direct inverse dynamics to solve the muscle redundancy problem at human lower limbs is proposed. It aims at computing lower limb joints moments under dynamic conditions using only electromyographic (EMG) signals in combination with an auto regressive moving average (ARMA) model. The experimental protocol is conducted by practicing full gait cycle trials in an effort to calculate joint moments. Quantitative comparisons with the output of a biological-based model showed that the proposed method is able to: 1) produce accurate estimates of the resultant moment; 2) maintain the obtained accuracy regardless of the information about status of the angle or its derivatives. The joint moment prediction by the ARMA model attained an average of R2 = 1.73. The model is characterised by stability, accuracy and minimum number of input variables. These characteristics represent an added value to be utilised in lower limbs rehabilitation.","PeriodicalId":90184,"journal":{"name":"International journal of experimental and computational biomechanics","volume":"2 1","pages":"245"},"PeriodicalIF":0.0,"publicationDate":"2014-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1504/IJECB.2014.060402","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66745041","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-04-14DOI: 10.1504/IJECB.2014.060398
A. Rezaei, M. S. Jazi, S. Javid, G. Karami, M. Ziejewski
We examine the effects of blast waves in a confined space on a human head model. A finite element human model (FEHM) is exposed to blast waves from explosions, as well as, to the reflected waves from the confinement walls. The intensity of the travelling blast shock waves is measured computationally and compared with experimental results. We monitor the mechanical response of the brain of the FEHM at different stand-off positions, either close to, or away from the surrounding walls in interaction with the travelling blast waves. The skull pressure, brain intracranial pressure (ICP), acceleration, shear stress, and principal stresses and strains are measured as the biomechanical parameters for injury diagnosis and compared for all the situations and stand-off positions considered. The results illustrate that the additional reflected shock waves due to the surrounding walls can dramatically change the brain biomechanical parameters.
{"title":"Confined blasts, and the impact of shock wave reflections on a human head and the related traumatic brain injury","authors":"A. Rezaei, M. S. Jazi, S. Javid, G. Karami, M. Ziejewski","doi":"10.1504/IJECB.2014.060398","DOIUrl":"https://doi.org/10.1504/IJECB.2014.060398","url":null,"abstract":"We examine the effects of blast waves in a confined space on a human head model. A finite element human model (FEHM) is exposed to blast waves from explosions, as well as, to the reflected waves from the confinement walls. The intensity of the travelling blast shock waves is measured computationally and compared with experimental results. We monitor the mechanical response of the brain of the FEHM at different stand-off positions, either close to, or away from the surrounding walls in interaction with the travelling blast waves. The skull pressure, brain intracranial pressure (ICP), acceleration, shear stress, and principal stresses and strains are measured as the biomechanical parameters for injury diagnosis and compared for all the situations and stand-off positions considered. The results illustrate that the additional reflected shock waves due to the surrounding walls can dramatically change the brain biomechanical parameters.","PeriodicalId":90184,"journal":{"name":"International journal of experimental and computational biomechanics","volume":"2 1","pages":"205"},"PeriodicalIF":0.0,"publicationDate":"2014-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1504/IJECB.2014.060398","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66745010","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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