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An electromyography system, kinetics and kinematics variables are insufficient to predict the failure-to-recover an impending loss of balance 肌电图系统、动力学和运动学变量不足以预测即将失去平衡时的失误恢复情况
Q4 Engineering Pub Date : 2020-03-31 DOI: 10.15593/rjbiomech/2020.1.06
M. L. Aguiar, Caluê Papcke, E. Scheeren
The body balance maintenance is performed through synchronized motor strategies, to preserve functional mobility. The purpose of this study is to compare the balance recovery mechanisms among young adults in an impending loss of balance. Thirty healthy young adult [age 24.87±4.16; weight 72.69±14.73 kg; growth 1.72±0.08 m] participated in the study. Seven perturbations were applied with a progressive velocity of the perturbation, in the antero-posterior direction. The following variables were analyzed: active time of muscle contraction, latency and displacement amplitude of the center of pressure, and angular variation of the ankle. For each perturbation, the subjects were classified according to their ability to recover balance: “no step” and step forward or hold the rope of the safety vest support. There were no significant differences between groups in all variables analyzed. At lower velocities of displacement, the group of “no step” presented greater angular variation for the knee joint, lower pressure center displacement range, and lower active time of normalized contraction of the muscle anterior tibial. The results suggest that the variables analyzed were insufficient to identify significant differences in the adoption of strategies for recovery of balance in an impending loss of balance.
身体平衡的保持是通过同步运动策略来实现的,目的是保持功能性活动能力。本研究的目的是比较即将失去平衡的年轻成年人的平衡恢复机制。30 名健康青壮年[年龄 24.87±4.16;体重 72.69±14.73kg;身高 1.72±0.08 m]参加了研究。研究人员在前后方向以渐进的速度施加了七次扰动。对以下变量进行了分析:肌肉收缩的有效时间、压力中心的潜伏期和位移幅度以及踝关节的角度变化。对于每次扰动,受试者根据其恢复平衡的能力进行分类:"不迈步 "和向前迈步或握住安全背心支撑绳。在分析的所有变量中,各组之间均无明显差异。在较低的位移速度下,"不迈步 "组的膝关节角度变化较大,压力中心位移范围较小,胫前肌正常化收缩的活动时间较短。结果表明,所分析的变量不足以确定在即将失去平衡时采取恢复平衡策略的显著差异。
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引用次数: 0
In vitro wear investigation of polyether ether ketone biopolymer for total knee replacement 用于全膝关节置换术的聚醚醚酮生物聚合物的体外磨损研究
Q4 Engineering Pub Date : 2020-03-31 DOI: 10.15593/rjbiomech/2020.1.05
Sandeep Kumar, K.V.S. Rajeswara Rao, Sunil R. Yalamalle
Nowadays, the average life span of knee prosthesis used in total knee replacement is approximately 10 to 15 years. The prevention of failure for these implants has been a constant struggle for orthopaedic surgeons and engineers. The reason behind for implant failures includes wear, infection, instability and stiffness. The major causes of failure are wear and tear of prosthesis. The most common biomaterials used in total knee replacement rubbing against a mating component of ultra-high-molecular-weight polyethylene are titanium alloy Ti6AI4V and alloy CoCrMo. The main drawback is that implants are still restrained by tiny ultra-high molecular weight poly debris generated by long term friction between femoral component and polyethylene articulating surface. Hence, the attempt is made to reduce the wear rate by replacing with high wear-resisting biomaterial. This research investigated whether polyether ether ketone was the appropriate material for total knee replacement by examining wear performance against Ti6AI4V. The experiments are conducted with different loading and speeds. The results are optimized by developing the regression equation using analysis of variance.
如今,用于全膝关节置换的膝关节假体的平均寿命约为 10 至 15 年。如何防止这些假体出现故障一直是矫形外科医生和工程师的难题。假体失效的原因包括磨损、感染、不稳定和僵硬。造成失败的主要原因是假体的磨损和撕裂。在全膝关节置换术中,最常用的生物材料是钛合金 Ti6AI4V 和钴铬钼合金。其主要缺点是植入物仍会受到股骨部件与聚乙烯关节表面长期摩擦产生的微小超高分子量聚乙烯碎片的限制。因此,人们试图用高耐磨的生物材料来替代,以降低磨损率。本研究通过检测聚醚醚酮与 Ti6AI4V 的磨损性能,研究聚醚醚酮是否是适合用于全膝关节置换的材料。实验以不同的负载和速度进行。利用方差分析建立回归方程,对结果进行优化。
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引用次数: 0
Biomechanical approach to dental orthopedic treatment of patients with postoperative defect of the upper jaw 对上颌骨术后缺损患者进行牙科矫形治疗的生物力学方法
Q4 Engineering Pub Date : 2020-03-31 DOI: 10.15593/rjbiomech/2020.1.03
Z. Shanidze, Sergey Muslov, Anatoly Arutyunov, Nataliya Astashina, Sergey Arutyunov
Replacement of postoperative maxillary defect of oncological origin in patients with complete absence of teeth is a difficult task. Based on the results of mechanical tests of structural materials and computer simulation of the biomechanics of the jaw prosthesis-obturator, the authors created improved obturator designs with specified design characteristics, which ensured the effectiveness of dental orthopedic treatment of this category of patients.
对于全口无牙的肿瘤患者来说,上颌骨术后缺损的修复是一项艰巨的任务。根据结构材料力学测试结果和颌骨修复体-闭锁器生物力学计算机模拟结果,作者设计出了具有特定设计特征的改良闭锁器,确保了这类患者牙科矫形治疗的有效性。
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引用次数: 1
Optimal time task in saccadic eye movement 眼球移动中的最佳时间任务
Q4 Engineering Pub Date : 2020-03-31 DOI: 10.15593/rjbiomech/2020.1.04
A. Kruchinina
This article is devoted to fast goal-directed human eye movements. Such movements are described in few ways. One of them is the time-optimal problem model. It this work, the saccade – fast single conformable ballistic eye movement, is under consideration. Saccadic eye trajectory is described by time-optimal task solution. Differential equations system are based on pendulum model. It defines control moment applied from extraocular muscles to eye globe and movement of it. Main feature of the system is all values in suggested system have physical meaning and were found in published experimental investigations. Consideration of the moment applied from extraocular muscles to eye glob as control is main difference of the system from other models for eye movement in submitted works. In this case, the open-loop system has two real roots and one zero. The particular case of the ratio of real roots of 1:3 is analyzed in the article. As a result of modelling, trajectory characteristics closed to the saccades observed in experimental studies is obtained. On the basis of the constructed model, the parameters of the synthesized saccades were compared with the parameters obtained on the experimental sample. The obtained models can be used both for problems of physiology and medicine, and for constructing virtual reality environments. For example, when developing 3D interfaces, the use of a mathematical model makes it possible to optimize the elements arrangement using game theory.
本文专门讨论人类眼球的快速目标定向运动。这种运动有几种描述方式。其中一种是时间最优问题模型。在这项工作中,考虑的是眼球的快速单顺应弹道运动。眼球运动轨迹由时间最优任务解决方案描述。微分方程系统基于钟摆模型。它定义了从眼外肌到眼球的控制力矩以及眼球的运动。该系统的主要特点是所建议系统中的所有值都具有物理意义,并在已发表的实验研究中被发现。将眼外肌对眼球施加的力矩视为控制力矩,是该系统与已提交作品中其他眼球运动模型的主要区别。在这种情况下,开环系统有两个实数根和一个零根。文章分析了实根比为 1:3 的特殊情况。建模的结果是获得了与实验研究中观察到的眼球移动轨迹特征相接近的眼球移动轨迹。在所建模型的基础上,将合成的囊状投影参数与实验样本中获得的参数进行了比较。获得的模型既可用于解决生理学和医学问题,也可用于构建虚拟现实环境。例如,在开发三维界面时,使用数学模型可以利用博弈论优化元素排列。
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引用次数: 0
Biaxial mechanical characterization and constitutive modelling of sheep sclera soft tissue 绵羊巩膜软组织的双轴机械特性和构成模型
Q4 Engineering Pub Date : 2020-03-31 DOI: 10.15593/rjbiomech/2020.1.09
Zwelihle Ndlovu, F. Nemavhola, Dagwood Desai
Constant exposure to the environment, head trauma and shaking of ocular tissues result in damage and disorders of the eye. In the United States, trauma alone causes about 30 000 people each year to lose vision in one eye. The sclera soft tissue plays a vital role in protecting, maintaining the shape of the eye and regulating the intraocular pressure, and is closely linked with glaucoma. The aim of the study was to investigate and compare the mechanical response of sheep sclera soft tissue under equibiaxial tension as data from such studies are limited. The material parameters describing the mechanical behaviour were determined using the Fung and Choi–Vito models. Sheep eyes were transported in ice and tested in saline solution at a temperature 37° C using within 4 to 6 hours after slaughter. Sheep sclera tissue was found to be nonlinear and anisotropic with average anisotropy constants (A) of 0.69 and 0.74 for the Fung and Choi–Vito models, respectively. The coefficients of correlation (R2 ) between the experimental and hyperelastic models were found to be 0.98 and 0.95 respectively, with Fung model providing the best fit and more anisotropic behaviour than the Choi–Vito model.
持续暴露在环境中、头部外伤和眼部组织的晃动都会导致眼睛受损和失明。在美国,每年仅外伤就会导致约 3 万人单眼失明。巩膜软组织在保护、维持眼球形状和调节眼压方面起着至关重要的作用,与青光眼密切相关。这项研究的目的是调查和比较绵羊巩膜软组织在等轴张力下的机械响应,因为此类研究的数据有限。使用 Fung 和 Choi-Vito 模型确定了描述机械性能的材料参数。绵羊眼睛在屠宰后 4 至 6 小时内用冰运输,并在温度为 37°C 的生理盐水溶液中进行测试。研究发现,绵羊巩膜组织是非线性和各向异性的,Fung 和 Choi-Vito 模型的平均各向异性常数 (A) 分别为 0.69 和 0.74。实验模型和超弹性模型之间的相关系数(R2)分别为 0.98 和 0.95,其中 Fung 模型的拟合效果最好,各向异性也比 Choi-Vito 模型更强。
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引用次数: 10
Aspect ratio as a factor predicting rupture of cerebral aneurysms 纵横比是预测脑动脉瘤破裂的一个因素
Q4 Engineering Pub Date : 2020-03-31 DOI: 10.15593/rjbiomech/2020.1.01
Dmitriy Ivanov, Aleksandr V. Dol, Leonid Kossovich
Cerebral vascular aneurysms are abnormalities present in 2–5% of the population. Aneurysm rupture often leads to the development of a hemorrhagic stroke. Among its consequences are disability and death. Despite this, preventive surgical treatment of aneurysms is not always justified, since it leads to serious postoperative complications. In this regard, there is the problem of developing and justifying reliable and convenient criteria for assessing the risk of aneurysm rupture. Aspect ratio (the ratio of the height of the aneurysm to the diameter of the neck) is the relative size of the aneurysms used to classify them as prone to rupture and not prone to rupture. This characteristic is also used as predictor of aneurysm rupture. In this paper, we carried out a series of numerical biomechanical calculations aimed at substantiating the critical value of the aspect ratio characterizing aneurysms prone to rupture. In the simulation, the average shear stresses on the aneurysm wall were compared for different aspect ratios from 0.5 to 2.25 with a step of 0.25 for asymmetric models and for aspect ratios from 0.5 to 2.1 with a step of 0.2 for symmetrical models. It was revealed that average wall shear stresses on the aneurysm significantly decrease when the aspect ratio is greater than critical. An abrupt decrease in the average wall shear stresses on the aneurysm with aspect ratio greater than the critical value was revealed.
脑血管动脉瘤是一种异常现象,发病率占总人口的 2-5%。动脉瘤破裂通常会导致出血性中风。其后果包括残疾和死亡。尽管如此,动脉瘤的预防性手术治疗并不总是合理的,因为它会导致严重的术后并发症。在这方面,有一个问题是如何制定和证明评估动脉瘤破裂风险的可靠而方便的标准。纵横比(动脉瘤高度与颈部直径之比)是动脉瘤的相对大小,用于将动脉瘤分为易破裂和不易破裂两种。这一特征也被用作动脉瘤破裂的预测指标。在本文中,我们进行了一系列生物力学数值计算,旨在证实动脉瘤易破裂特征的纵横比临界值。在模拟中,我们比较了不同纵横比的动脉瘤壁平均剪应力,非对称模型的纵横比从 0.5 到 2.25,步长为 0.25;对称模型的纵横比从 0.5 到 2.1,步长为 0.2。结果表明,当纵横比大于临界值时,动脉瘤的平均壁剪应力会明显降低。当纵横比大于临界值时,动脉瘤壁上的平均剪切应力突然下降。
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引用次数: 0
Analysis of kinematics of the approach run in long jump event among Jordanian male team 约旦男队跳远项目接近跑运动学分析
Q4 Engineering Pub Date : 2020-03-31 DOI: 10.15593/rjbiomech/2020.1.02
Osama Abdel Fattah, A. Bataineh
The purpose of this investigation was to study kinematic variables at the approach run and take-off phase. Furthermore, to study the relationships between these kinematic variables among Jordanian male team in long jump event. To achieve this, four elite male jumpers from the Jordanian male team (age 18±0.6 years; height 180±2 cm; mass 72±2 kg; the leg length 87±1 cm; training age 4±0.58 years) were studied. Subjects were filmed by digital video cameras (Nikon D3400, 60 fps). The first camera was placed 20 m lateral from the center of the approach run to capture the steps, vertical height of the camera was 1.2 m. The second camera was positioned to capture the last two strides and take-off phase, this camera was placed 8 m lateral from the last two stride to capture other study variables, vertical height of the camera was 1 m. The video data were performed with Kinovea analysis program (version 0.8.2764 × 64), where the best attempt was analyzed. This study involved 15 kinematic variables. According to the results obtained in this study, we can conclude that the subjects of this study show asymmetrical results in most study variables except touch-down time variable. Furthermore, one interesting finding is that a height of center of mass at take-off variable is the only one that has a statistically significant relationship with the achievement distance (r = 0.949). Finally, it is recommended the establishment of a kinetic file for each long jumpers.
本次调查的目的是研究接近跑和起飞阶段的运动学变量。此外,还研究约旦男子跳远队中这些运动变量之间的关系。为此,对约旦男子跳远队的四名精英运动员(年龄 18±0.6 岁;身高 180±2 厘米;体重 72±2 公斤;腿长 87±1 厘米;训练年龄 4±0.58 岁)进行了研究。研究对象由数码摄像机(尼康 D3400,60 fps)拍摄。第一台摄像机放置在距离进场跑中心外侧 20 米处,以捕捉步法,摄像机垂直高度为 1.2 米;第二台摄像机放置在距离最后两步和起飞阶段外侧 8 米处,以捕捉其他研究变量,摄像机垂直高度为 1 米。这项研究涉及 15 个运动学变量。根据本研究获得的结果,我们可以得出结论:除了触地时间变量外,本研究的受试者在大多数研究变量上都表现出不对称的结果。此外,一个有趣的发现是,起飞时的质心高度变量是唯一一个与成绩距离有显著统计学关系的变量(r = 0.949)。最后,建议为每位跳远运动员建立一份运动档案。
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引用次数: 1
The problem of "gymnast" motion control in free flight and during the transition in the state of contact with the support 体操运动员 "在自由飞行和与支撑物接触状态过渡期间的运动控制问题
Q4 Engineering Pub Date : 2020-03-31 DOI: 10.15593/rjbiomech/2020.1.07
Eduard Lavrovskii
The study from the position of theoretical mechanics discusses some aspects of the jump down of the "gymnast" – athlete (or the robot – "gymnast") from the "crossbar". We discuss all phases of the jump in the planar case. "Gymnast" body is modeled as three-links physical pendulum, however, after departing from the "crossbar" and lowering the "hands" model the dynamic system becomes two-links pendulum. For a two-links model in the regime of "kinematic" control, we deal with the process of lowering hands, free flight, the output of the "legs" on the frame (absolutely inelastic impact) and holding operation in support phase with the aim of vertical stabilize of the pendulum system. Mode "kinematic control" means the ability to instantly change the angle between the links of the body (in some limits). For each of the phases of movement, we found a convenient form of describing dynamical equations. These equations are based on the use as a variable momentum of the system relative to various points of the body or space. The order of this system of equations is lower than for the full order system. The stage of calm "gymnast" that occurs after the foot on the surface of the support, will also be examined on the basis of special system of equations of this type. It was shown, that we can use numerical analysis to build the region of controllability for transition of the two-links model in a state of stabilization, corresponding to the equality of the horizontal coordinate of the support foot and the center of gravity of the two-links pendulum system. The algorithm of stabilizing control is designed. The results of presented of the analysis of the problem allow us to construct a convenient approximate model of the phenomenon as a whole, and to use it to control a robotic counterpart. As an example, it is considered one of the cases of motion that corresponds to the anthropomorphic model.
本研究从理论力学的角度讨论了 "体操运动员"--运动员(或机器人--"体操运动员")从 "横杆 "上向下跳跃的某些方面。我们讨论了平面情况下跳跃的所有阶段。"体操运动员 "的身体被建模为三连杆物理摆,然而,在离开 "横杆 "并放下 "手 "模型后,动态系统变成了两连杆摆。对于 "运动学 "控制模式下的双连杆模型,我们处理的是手的下降过程、自由飞行、"腿 "在框架上的输出(绝对无弹性冲击)和支撑阶段的保持操作,目的是使摆锤系统垂直稳定。运动控制 "模式指的是瞬间改变身体各环节之间角度的能力(在一定范围内)。对于每个运动阶段,我们都找到了一种方便的动态方程描述形式。这些方程以系统相对于身体或空间各点的可变动量为基础。该方程系统的阶数低于全阶系统。在脚踏上支撑物表面之后出现的 "体操运动员 "的平静阶段,也将根据这种类型的特殊方程组进行研究。结果表明,我们可以使用数值分析来建立双连杆模型在稳定状态下过渡的可控区域,稳定状态对应于支撑脚的水平坐标和双连杆摆系统的重心相等。设计了稳定控制算法。根据对问题的分析结果,我们可以方便地构建一个整体现象的近似模型,并用它来控制对应的机器人。作为一个例子,我们考虑了与拟人模型相对应的一种运动情况。
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引用次数: 0
Effectiveness of Blalock–Taussig shunt performance in the congenital heart disease children 布洛克-陶西格分流术在先天性心脏病患儿中的应用效果
Q4 Engineering Pub Date : 2020-03-31 DOI: 10.15593/rjbiomech/2020.1.08
A. Kuchumov, A. Khairulin, A. Biyanov, A. Porodikov, Vagram Aratyunyan, Yuriy Sinelnikov
A problem of congenital heart defects with obstruction of the right ventricle output tract is urgent because of disease severity and need for multistage surgical treatment. The first stage of surgical correction is system–pulmonary shunt installation. Nevertheless, there are controversial views on the choice of the shunt optimal diameter and the implantation place selection. Anastomosis should provide sufficient, but no excessive pulmonary blood flow without reducing cardiac output, pulmonary vessels damage, and provide uniform growth of pulmonary arteries. In this paper, the model of blood flow in "aorta–shunt–pulmonary artery" is considered. A set of geometric images was obtained in four patients for the further import into ANSYS CFX finite element solver to solve the hemodynamic problem. Three variants of the modified Blalock–Taussig shunt installation were analyzed with by using widely adopted hemodynamic indices (wall shear stress, time averaged wall shear stress, oscillatory shear index, relative residence time). It was shown that shunting options differ for the various patients. Moreover, flow asymmetry in the pulmonary arteries at different implantation sites was noticed. Also, a comparison of hemodynamic performance was made to assess the effectiveness of the modified Blalock– Taussig shunt. An objectivized and personalized approach to specific treatment of each patient will significantly reduce child mortality and improve the quality of rehabilitation.
先天性心脏缺陷合并右心室输出道梗阻的问题,由于病情严重,急需进行多阶段手术治疗。手术矫正的第一阶段是安装系统-肺分流管。然而,对于分流管最佳直径的选择和植入位置的选择还存在争议。吻合器应提供充足但不过量的肺血流,同时不降低心输出量、不损伤肺血管,并使肺动脉均匀生长。本文考虑了 "主动脉-分流-肺动脉 "的血流模型。本文获得了四名患者的一组几何图像,并将其进一步导入 ANSYS CFX 有限元求解器,以解决血流动力学问题。利用广泛采用的血液动力学指标(壁剪切应力、时间平均壁剪切应力、振荡剪切指数、相对停留时间)分析了改良布洛克-陶西格分流装置的三种变体。结果表明,不同患者的分流方案各不相同。此外,还发现不同植入部位的肺动脉血流不对称。此外,还对血液动力学表现进行了比较,以评估改良布洛克-陶西格分流术的有效性。针对每位患者的具体治疗采取客观化和个性化的方法,将大大降低儿童死亡率并提高康复质量。
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引用次数: 3
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Russian Journal of Biomechanics
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