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A 2D Transient Computational Multi-Physics Model for Analyzing Magnetic and Non-Magnetic Particle (Red Blood Cells and E. Coli bacteria) Dynamics in a Travelling Wave Ferro-Magnetic Microfluidic Device for Potential Cell Separation and Sorting 在行波铁磁微流控装置中分析磁性和非磁性粒子(红细胞和大肠杆菌)动力学的二维瞬态计算多物理模型
Pub Date : 2023-05-18 DOI: 10.1115/1.4062571
Rodward L. Hewlin, Maegan Edwards, Michael Smith
This paper presents the theory and development, validation, and results of a transient computational multi-physics model for analyzing the magnetic field, particle dynamics, and capture efficiency of magnetic and non-magnetic (e.g., Red Blood Cells and E. Coli bacteria) microparticles in a travelling wave ferro-magnetic microfluidic device. This computational model demonstrates proof-of-concept of a method for greatly enhancing magnetic bio-separation in ferro-microfluidic systems using an array of copper conductive elements arranged in quadrature to create a periodic potential energy landscape. In contrast to previous works, our approach theoretically uses a microfluidic device with an electronic chip platform consisting of integrated copper electrodes that carry currents to generate programmable magnetic field gradients locally. Alternating currents are applied to the electrodes in quadrature (using a 90° phase change from the neighboring electrode) to create a periodic magnetic field pattern that travels along the length of the microchannel. Our previous work evaluated magnetic and non-magnetic particles in a static magnetic field within the same channel geometry. This work is a phase 2 study that expands on the previous work and analyzes the dynamics of magnetic and non-magnetic entities characterized by material magnetic susceptibility in a transient magnetic field. This is an improvement over our previous work. The model, which is described in more detail in the methods section, combines a Eulerian-Lagrangian and two-way particle-fluid coupling CFD analysis with closed-form magnetic field analysis that is used to predict magnetic separation considering dominant magnetic and hydrodynamic forces similar to our previous works in magnetic drug targeting. The model was also validated with an experimental low frequency stationary flow study on separating non-magnetic latex fluorescent particles in a water based ferrofluid. The results from the experimental study and the developed model demonstrates that the proposed device may potentially be used as an effective platform for microparticle and cellular manipulation and sorting. The developed multi-physics model could potentially be used as a design optimization tool for traveling wave ferro-microfluidic devices.
本文介绍了一种瞬态计算多物理模型的理论、发展、验证和结果,该模型用于分析行波铁磁微流控装置中磁性和非磁性(如红细胞和大肠杆菌)微粒子的磁场、粒子动力学和捕获效率。该计算模型证明了一种方法的概念验证,该方法可以极大地增强铁微流体系统中的磁性生物分离,该方法使用一组铜导电元件以正交方式排列以创建周期性势能景观。与以前的工作相比,我们的方法在理论上使用了一个带有电子芯片平台的微流体装置,该电子芯片平台由集成的铜电极组成,该电极携带电流,以在局部产生可编程的磁场梯度。交流电被施加到正交电极上(使用来自相邻电极的90°相位变化),以产生沿微通道长度传播的周期性磁场图案。我们之前的工作评估了在相同通道几何形状的静态磁场中的磁性和非磁性颗粒。本工作是第二阶段的研究,扩展了之前的工作,并分析了瞬变磁场中以材料磁化率为特征的磁性和非磁性实体的动力学。这比我们以前的工作有了改进。该模型将欧拉-拉格朗日和双向粒子-流体耦合CFD分析与封闭形式的磁场分析相结合,考虑主导磁力和流体动力,用于预测磁分离,类似于我们之前在磁性药物靶向方面的工作。该模型还通过在水基铁磁流体中分离非磁性乳胶荧光颗粒的实验低频稳态流动研究进行了验证。实验研究和开发的模型的结果表明,所提出的设备可能被用作微粒和细胞操作和分类的有效平台。所建立的多物理场模型可作为行波铁磁微流控器件的优化设计工具。
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引用次数: 5
Design and Development of Patient-specific Miniplate for the Treatment of Maxillofacial Fractures-A Finite Element Study 用于治疗颌面骨折的患者专用微型钢板的设计与研制——有限元研究
Pub Date : 2023-05-15 DOI: 10.1115/1.4062509
Sandeep Choudhury, Anik Banerjee, S. Majumder, A. Roychowdhury
Fractures of the maxillofacial region are prevalent in both developed and developing nations. Maxillofacial fractures primarily occur as a result of incidents such as car crashes, physical assaults, and attacks. Although using miniplates to treat maxillofacial fractures is a widely accepted practice, the challenge lies in selecting the appropriate miniplate size that is tailored to the specific dimensions of the fracture in each patient. The study aims to evaluate and determine the most suitable design between a 2-hole miniplate and a 4-hole miniplate for securing a fractured mandible, with the ultimate goal of creating a customized solution for each patient. A mandible model is chosen with a diagonal length of 82mm and created perpendicular fracture gaps measuring 1mm to 3mm on the left buccolingual section of the solid model. A 2-hole and a 4-hole miniplate are designed with different thicknesses (ranging from 1mm to 2mm) and gap distances (ranging from 6mm to 12mm). The miniplates were put together in a model of the mandible. To test their effectiveness, the combination of the mandible model and plates was subjected to various muscle forces, as well as the force of biting, using finite element analysis. At the mandible location, the four-hole miniplate implantation exhibits superior stabilization in comparison to the two-hole miniplate assembly. The miniplate's size and dimensions can be adjusted depending on the size of the fracture in the mandible, resulting in a patient-specific solution for the implantation of miniplate in the mandible.
颌面骨折在发达国家和发展中国家都很普遍。颌面部骨折主要是由于车祸、人身攻击和袭击等事故造成的。尽管使用微型钢板治疗颌面部骨折是一种被广泛接受的做法,但挑战在于根据每位患者的具体骨折尺寸选择合适的微型钢板尺寸。该研究旨在评估和确定用于固定骨折下颌骨的2孔微型钢板和4孔微型钢板之间最合适的设计,最终目标是为每位患者创建定制的解决方案。选择对角线长度为82mm的下颌骨模型,在实体模型的左颊舌部分创建1mm至3mm的垂直骨折间隙。设计了不同厚度(1mm ~ 2mm)和间隙距离(6mm ~ 12mm)的2孔和4孔微型板。这些小板被放在一起做成了一个下颌骨模型。为了验证其有效性,使用有限元分析对下颌骨模型和钢板的组合进行了各种肌肉力以及咬合力的测试。在下颌骨位置,与两孔微型钢板组合相比,四孔微型钢板植入具有更好的稳定性。微型钢板的大小和尺寸可以根据下颌骨骨折的大小进行调整,从而为下颌骨植入微型钢板提供患者特异性解决方案。
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引用次数: 0
Is It Feasible to Reconstruct Aortic Pressure Waveform Based On a 1d Uniform Model of the Arterial Tree? 基于动脉树一维均匀模型重建主动脉压波形可行吗?
Pub Date : 2023-05-05 DOI: 10.1115/1.4062468
Z. Hao
Based on a 1D uniform model of the arterial tree, various machine-learning techniques have been explored to reconstruct aortic pressure waveform (APW) from peripheral pressure waveform (PPW). This study aims to examine the feasibility of such reconstruction. Based on a 1D uniform vibrating-string model, transfer function (TF) of PPW to APW contains four harmonics-dependent parameters: value and phase of reflection coefficient (i.e., load impedance) at periphery and transmission parameter and transmission loss in the aorta-periphery section, and they are all harmonics-dependent. Pressure waveforms and blood velocity waveforms at the ascending aorta (AA), the carotid artery (CA), and the radial artery (RA) at different ages in a database are analyzed to calculate 1) reflection coefficient at the CA and the RA as two peripheries, 2) TF for the AA-CA and AA-RA sections, and 3) transmission parameter and transmission loss in the two sections. Harmonics-dependence of the four parameters varies with aging for both sections, revealing unpracticality of any mathematical model for harmonics-dependence of load impedance. Compared with fluid-loading, arterial non-uniformity significantly affects wave transmission. Transmission loss dramatically alters reconstructed APW, relative to higher harmonics. A 1D uniform model allows accurate reconstruction of APW from PPW, with a caveat that baseline values for the four parameters at different harmonics under different cardiovascular (CV) conditions need to be established a priori. Alternatively, based on the baseline values, PPW can be directly utilized for inferring the CV conditions.
基于动脉树的一维均匀模型,研究人员探索了各种机器学习技术来从外周压力波形(PPW)重建主动脉压力波形(APW)。本研究旨在探讨这种重建的可行性。基于一维均匀振动弦模型,PPW到APW的传递函数(TF)包含四个谐波相关参数:外围反射系数(即负载阻抗)的值和相位以及主动脉-外围段的传输参数和传输损耗,它们都是谐波相关的。分析数据库中不同年龄的升主动脉(AA)、颈动脉(CA)和桡动脉(RA)的压力波形和血流速度波形,计算1)CA和RA作为两个外围的反射系数,2)AA-CA和AA-RA断面的TF, 3)两个断面的传输参数和传输损失。这四个参数的谐波依赖关系随两个部分的老化而变化,表明负载阻抗谐波依赖的任何数学模型都不实用。与流体加载相比,动脉不均匀性显著影响波的传播。相对于高次谐波,传输损耗显著地改变了重构APW。一维均匀模型可以精确地从PPW重建APW,但需要注意的是,需要先验地建立不同心血管(CV)条件下四个参数在不同谐波下的基线值。或者,基于基线值,PPW可以直接用于推断CV条件。
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引用次数: 0
Measurement of Brain Strains in a Goat Head Under Impact Loading 冲击载荷下山羊头部脑张力的测量
Pub Date : 2023-05-05 DOI: 10.1115/1.4062467
Abhilash Singh, Y. Naing, S. Ganpule
Measurements of brain deformations under dynamic loading are required to understand the biomechanics of Traumatic Brain Injury (TBI). In this work, we have experimentally measured 2D brain deformations in a sacrificed goat brain under injurious impact loading. To facilitate imaging, the goat head was dissected along the longitudinal midline. Goat head response was studied for sagittal plane rotation. Full-field, 2D deformations in the midsagittal plane of a goat brain were obtained at spatiotemporal resolutions of ~1 mm and 0.4 ms, respectively. Results elucidate the dynamic strain evolution. The goat brain underwent large deformation. The strain pattern was heterogeneous. Peak strains in various brain regions were established within ~20 ms, followed by negligible strain development due to the considerable viscous dissipation. The Cerebellum region experienced the highest strain, followed by cortical and subcortical regions. Strain concentration in the goat brain near the stiff membrane of the tentorium was observed. The strains in a brain simulant of a head surrogate (obtained previously) were also compared against the goat brain response. A response in the brain simulant was comparable to the goat brain in terms of strain pattern, peak strains in various substructures, and strain concentration near the membrane. However, the brain simulant was less dissipative than the goat brain. These results enhance the current understanding of the biomechanics of the brain under dynamic loading.
动态载荷下脑变形的测量是了解创伤性脑损伤(TBI)生物力学的必要条件。在这项工作中,我们通过实验测量了在损伤冲击载荷下牺牲的山羊大脑的二维脑变形。为了便于成像,沿纵向中线解剖山羊头。研究了山羊头部对矢状面旋转的响应。在~1 mm和0.4 ms的时空分辨率下,分别获得了山羊大脑中矢状面全场二维形变。结果阐明了动态应变演化。山羊的大脑发生了很大的变形。应变模式是异质的。各脑区的峰值应变在~ 20ms内建立,随后由于相当大的粘性耗散,应变发展可以忽略不计。小脑区承受的压力最大,其次是皮质区和皮质下区。观察了山羊脑幕硬膜附近的应变浓度。我们还将大脑模拟物(先前获得的)中的菌株与山羊的大脑反应进行了比较。在应变模式、各种亚结构的峰值应变和膜附近的应变浓度方面,脑模拟物的响应与山羊脑相当。然而,大脑模拟物的耗散比山羊大脑要小。这些结果增强了目前对动态负荷下大脑生物力学的理解。
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引用次数: 0
Decoupling Uniaxial Tensile Prestress and Waveguide Effects From Estimates of the Complex Shear Modulus in a Cylindrical Structure Using Transverse-Polarized Dynamic Elastography. 利用横向极化动态弹性图从圆柱结构的复合剪切模量估计中解耦单轴拉伸预应力和波导效应。
Pub Date : 2023-05-01 DOI: 10.1115/1.4056411
Melika Salehabadi, Joseph Crutison, Dieter Klatt, Thomas J Royston

Dynamic elastography, whether based on magnetic resonance, ultrasound, or optical modalities, attempts to reconstruct quantitative maps of the viscoelastic properties of biological tissue, properties altered by disease and injury, by noninvasively measuring mechanical wave motion in the tissue. Most reconstruction strategies that have been developed neglect boundary conditions, including quasi-static tensile or compressive loading resulting in a nonzero prestress. Significant prestress is inherent to the functional role of some biological tissues currently being studied using elastography, such as skeletal and cardiac muscle, arterial walls, and the cornea. In the present article a configuration, inspired by muscle elastography but generalizable to other applications, is analytically and experimentally studied. A hyperelastic polymer phantom cylinder is statically elongated in the axial direction while its response to transverse-polarized vibratory excitation is measured. We examine the interplay between uniaxial prestress and waveguide effects in this muscle-like tissue phantom using computational finite element simulations and magnetic resonance elastography measurements. Finite deformations caused by prestress coupled with waveguide effects lead to results that are predicted by a coordinate transformation approach that has been previously used to simplify reconstruction of anisotropic properties using elastography. Here, the approach estimates material viscoelastic properties that are independent of the nonhomogeneous prestress conditions without requiring advanced knowledge of those stress conditions.

动态弹性成像,无论是基于磁共振、超声还是光学模式,都试图通过无创测量组织中的机械波运动来重建生物组织粘弹性特性的定量图,这些特性因疾病和损伤而改变。大多数已经开发的重建策略忽略了边界条件,包括导致非零预应力的准静态拉伸或压缩加载。重要的预应力是固有的一些生物组织的功能作用,目前正在研究使用弹性成像,如骨骼肌和心肌,动脉壁和角膜。在本文中,一种构型,灵感来自肌肉弹性,但可推广到其他应用,是分析和实验研究。研究了超弹性聚合物模体在轴向上的静态拉伸,并测量了其对横向极化振动激励的响应。我们使用计算有限元模拟和磁共振弹性测量来研究这种肌肉样组织幻影中单轴预应力和波导效应之间的相互作用。由预应力和波导效应引起的有限变形导致的结果可以通过坐标变换方法预测,该方法先前用于简化弹性成像的各向异性特性重建。在这里,该方法估计了材料的粘弹性特性,这些特性与非均匀预应力条件无关,而不需要对这些应力条件有深入的了解。
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引用次数: 0
Biomechanical Analysis of Mandibular Bone-Implant Construct with Three Implant Screw Design: A Finite Element Study 下颌骨-种植体三种植体螺钉设计的生物力学分析:有限元研究
Pub Date : 2023-04-28 DOI: 10.1115/1.4062437
Anik Banerjee, Sandeep Choudhury, Masud Rana, Arindam Chakraborty, Abhisek Gupta, A. Chowdhury
Temporomandibular joint replacement (TMJR) is a surgical procedure that relies heavily on the biomechanical properties of the implant-bone interface for success. In this study, we investigated the effects of three commonly used implant screw thread designs (buttress, square, and triangle) on the biomechanical performance of the mandibular bone-implant construct, with the aim of improving osseointegration. Using finite element analysis, we simulated the mechanical behavior of the prosthesis and mandible and examined the biomechanics of the temporomandibular joint. We considered five coefficients of friction ranging from 0.1 to 0.5 in our analyses. Our hypothesis was that changing the screw thread shape while keeping the pitch, height, and depth constant could enhance the biomechanical environment at the peri-implant bone. Our results indicate that the square thread design produced the highest stress concentration, while the triangle thread design exhibited the most favorable distribution of stress around the implant. Furthermore, increasing the coefficient of friction led to an increase in stress concentration in the implant and surrounding bone. Our findings offer valuable insights into the biomechanical performance of different screw thread designs in the mandibular bone-implant construct. They highlight the significance of considering screw thread shape and coefficient of friction in TMJR implant design. Future studies should incorporate the viscoelastic properties of bone to improve the accuracy of finite element analysis. This research contributes to the optimization of TMJR implants and ultimately enhances patient outcomes.
颞下颌关节置换术(TMJR)是一种外科手术,其成功与否很大程度上依赖于种植体-骨界面的生物力学特性。在这项研究中,我们研究了三种常用的种植体螺纹设计(支撑型、方形和三角形)对下颌骨-种植体结构生物力学性能的影响,目的是改善骨整合。采用有限元方法模拟假体和下颌骨的力学行为,并对颞下颌关节的生物力学进行了研究。在我们的分析中,我们考虑了从0.1到0.5的五个摩擦系数。我们的假设是,在保持牙距、高度和深度不变的情况下改变螺纹形状可以改善种植体周围骨的生物力学环境。我们的研究结果表明,方螺纹设计产生了最高的应力集中,而三角形螺纹设计在种植体周围表现出最有利的应力分布。此外,增加摩擦系数导致种植体和周围骨的应力集中增加。我们的研究结果对不同设计的下颌骨种植体的生物力学性能提供了有价值的见解。他们强调了在TMJR种植体设计中考虑螺纹形状和摩擦系数的重要性。未来的研究应纳入骨的粘弹性特性,以提高有限元分析的准确性。本研究有助于TMJR种植体的优化,最终提高患者的预后。
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引用次数: 0
Tissue Growth Model for Maintaining Tensional Homeostasis with Applications to Hypertension and Stented Artery 维持张力稳态的组织生长模型及其在高血压和支架动脉中的应用
Pub Date : 2023-04-21 DOI: 10.1115/1.4062387
Pengfei Dong, K. Nunes, Linxia Gu
In this work, a theoretical growth model for maintaining a homeostatic mechanical environment was developed to capture the growth behavior of the artery and its association with its mechanical environment. The multiplicative decomposition approach was adopted to decompose the deformation matrix into an elastic term and a growth term. A growth factor in relation to homeostatic stress was used to regulate the progressive changes in the arterial morphology. In addition, a growth coefficient was adopted to avoid unlimited growth. Arterial growth model was implemented in a commercial finite element software and tested in the cases of hypertension and stenting. Results have demonstrated that the arterial growth induced by hypertension can mitigate abnormal arterial stresses and restore the stress level in the artery back to its homeostasis. Following stenting, the arterial growth pattern was consistent with the distribution of the von Mises stresses in the artery. The arterial growth homogenized the stress distribution in the artery, except for the regions under the stent struts. The heterogeneous growth of the artery disrupted the alignment of the maximum principal stresses in the artery, elongated the stent, reduced lumen area, and aggregated the tissue prolapse. It is expected that the growth model developed in this work could help to understand and regulate the chronic response of the tissue. Appropriate modeling of arterial growth in connection with tensional homeostasis provided insights for predicting alterations to the arterial mechanical environment, identifying biomechanical factors leading to restenosis, and design therapeutic strategies to regulate the tissue adaptations.
在这项工作中,建立了一个维持稳态机械环境的理论生长模型,以捕捉动脉的生长行为及其与机械环境的关联。采用乘法分解方法将变形矩阵分解为弹性项和生长项。一种与内稳态应激相关的生长因子被用来调节动脉形态的进行性变化。此外,为了避免无限生长,还采用了生长系数。动脉生长模型在商业有限元软件中实现,并在高血压和支架置入的情况下进行测试。结果表明,高血压引起的动脉生长可以减轻动脉异常应激,使动脉应激水平恢复到稳态。支架植入术后动脉生长模式与von Mises应力在动脉内的分布一致。动脉生长均匀化了动脉内的应力分布,除了支架支撑下的区域。动脉的不均匀生长破坏了动脉内最大主应力的排列,延长了支架,缩小了管腔面积,并聚集了组织脱垂。期望本研究建立的生长模型有助于理解和调节组织的慢性反应。适当的动脉生长模型与张力稳态相关,为预测动脉力学环境的改变、识别导致再狭窄的生物力学因素以及设计治疗策略来调节组织适应提供了见解。
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引用次数: 0
Evaluating the in Vitro Mechanical Responses of Stem Cell Under Fluid Perfusion in Different Porous Scaffolds 不同多孔支架液体灌注下干细胞体外力学反应的评价
Pub Date : 2023-04-17 DOI: 10.1115/1.4062340
S. Majumder, Abhisek Gupta, Sandeep Choudhury, Amit Roy Chowdhury
A suitable scaffold architecture is always desirable to get a favorable tissue response for bone tissue engineering. In this regard, a fluid-structure interaction analysis was carried out on different porous scaffolds to observe the in vitro mechanical responses due to fluid flow, followed by a submodeling method to obtain the cellular deformation and strain. Different types of scaffolds were designed based on different porosity and architecture. The cell was modelled with cytoplasm, nucleus, cell membrane, and cytoskeletons. The main objective of the study is to examine the variation of cellular responses due to different porosity and architecture of the scaffold. The results of this study highlight that permeability is higher in the case of gyroid structure and wall shear stress (WSS) is higher in the case of diamond structure. The permeability of all scaffolds increases with the increase of porosity. The opposite trend is shown in the case of WSS within scaffolds. The cell is showing higher deformation when it is placed on the front position of the scaffold towards the direction of fluid flow. This study will guide us in predicting an ideal scaffold for better cell growth.
在骨组织工程中,合适的支架结构是获得良好组织响应的关键。为此,我们对不同多孔支架进行流固耦合分析,观察其在流体流动作用下的体外力学响应,并采用子建模方法获得细胞变形和应变。根据不同的孔隙率和结构设计了不同类型的支架。用细胞质、细胞核、细胞膜和细胞骨架来模拟细胞。该研究的主要目的是研究由于支架的不同孔隙度和结构而引起的细胞反应的变化。研究结果表明,螺旋结构的渗透率较高,金刚石结构的壁剪应力(WSS)较高。各支架的透气性随孔隙率的增加而增加。支架内的WSS则呈现相反的趋势。当细胞朝向流体流动的方向放置在支架的前端位置时,细胞表现出更高的变形。这项研究将指导我们预测更好的细胞生长的理想支架。
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引用次数: 0
Design and Implementation of a Behavioral Sequence Framework for Human-robot Interaction Utilizing Brain-computer Interface and Haptic Feedback 基于脑机接口和触觉反馈的人机交互行为序列框架的设计与实现
Pub Date : 2023-04-17 DOI: 10.1115/1.4062341
Sudip Hazra, Shane Whitaker, P. Shiakolas
In assistive robotics, research in Brain-Computer-Interface aims to understand human intent with the goal to enhance Human-Robot-Interaction. In this research, a framework to enable a person with an upper limb disability to use an assistive system and maintain self-reliance is introduced and its implementation and evaluation are discussed. The framework interlinks functional components and establishes a behavioral sequence to operate the assistive system in three stages; action classification, verification, and execution. An action is classified based on identified human intent and verified through haptic and/or visual feedback before execution. The human intent is conveyed through facial expressions and verification through head movements. The interlinked functional components are an EEG sensing device, a head movement recorder, a dual-purpose glove, a visual feedback environment, and a robotic arm. The ability of the system to recognize a facial expression, time required to respond using head movements, convey information through vibrotactile feedback effects, and the ability to follow the established behavioral sequence are evaluated. Based on the evaluation, personalized training data set should be used to calibrate facial expression recognition and define the time required to respond during verification. Custom vibrotactile effects were effective in conveying system information to the user. Initial evaluation of the developed framework using three volunteers exhibited a 100% success rate in their ability to follow the behavioral sequence and control the system providing confidence to recruit more volunteers to identify and address improvements and expand the operational capability of the framework.
在辅助机器人中,脑机接口的研究旨在理解人的意图,以增强人与机器人的交互。在本研究中,介绍了一个框架,使上肢残疾者能够使用辅助系统并保持自力更生,并讨论了其实施和评估。该框架将功能组件相互连接,并建立了三个阶段的辅助系统运行行为序列;动作分类、验证和执行。动作是基于识别的人类意图进行分类,并在执行前通过触觉和/或视觉反馈进行验证。人类的意图通过面部表情传达,并通过头部动作验证。相互连接的功能组件是一个脑电图传感装置,一个头部运动记录仪,一个两用手套,一个视觉反馈环境和一个机械臂。系统识别面部表情的能力、通过头部运动做出反应所需的时间、通过振动触觉反馈效果传达信息的能力以及遵循既定行为序列的能力都将被评估。在评估的基础上,使用个性化的训练数据集来校准面部表情识别,并定义验证过程中响应所需的时间。自定义振动触觉效果在向用户传达系统信息方面是有效的。使用三名志愿者对开发的框架进行的初步评估显示,他们遵循行为顺序和控制系统的能力的成功率为100%,这为招募更多志愿者来识别和解决改进问题并扩展框架的操作能力提供了信心。
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引用次数: 0
A Computational Study Evaluating the Effects of Diffuser Length and Pullback Distance on the Ablation Zone During Laser Ablation Treatment of Liver Cancer 肝癌激光消融治疗中扩散器长度和回拉距离对消融区影响的计算研究
Pub Date : 2023-03-31 DOI: 10.1115/1.4062246
Zhi Q. Tan, E. Ooi, E. Ooi
Although laser ablation is not commonly used for liver cancer treatment, there are several benefits that make it an appealing alternative. Nevertheless, investigations on the efficacy of laser ablation for liver cancer has been limited to few clinical trials. Therefore, not much is known regarding the efficacy of the technique especially when operating under different protocols and device parameters. In this study, we performed a numerical study to investigate the effects of diffuser length, power density and the pullback technique on the coagulation zone formation during laser ablation of a spherical liver cancer. The objective is to demarcate the influence of diffuser length from power density, and to compare their performance to that when pullback is implemented. Four diffuser lengths (10, 15, 20 and 25 mm), and three pullback distances (5, 10 and 15 mm), were considered. Results showed that laser power density is a factor that limits the coagulation zone size when the diffuser length increases. A longer diffuser must be accompanied by an increase in laser power to achieve the desired treatment outcome. The pullback technique increases the effective diffuser length, but the coagulation volume obtained was smaller than that of a longer diffuser at the same power density. This suggests that increasing both the diffuser length and laser power is better at increasing the coagulation zone than the pullback technique. To obtain coagulation zone that is sufficiently large to cover the entire tumour, careful selection of the diffuser length, power density, and pullback distance is critical.
虽然激光消融不常用于肝癌治疗,但有几个好处使它成为一个有吸引力的选择。然而,关于激光消融治疗肝癌疗效的研究仅限于少数临床试验。因此,对于该技术的功效,特别是在不同的协议和设备参数下操作时,所知不多。在这项研究中,我们进行了数值研究,探讨扩散器长度、功率密度和回拉技术对球形肝癌激光消融过程中凝血区形成的影响。目的是区分扩散器长度与功率密度的影响,并将其性能与实现回拉时的性能进行比较。考虑了四种扩散器长度(10,15,20和25mm)和三种回拉距离(5,10和15mm)。结果表明,当扩散器长度增加时,激光功率密度是限制混凝区大小的一个因素。一个更长的扩散器必须伴随着激光功率的增加,以达到预期的治疗效果。拉回技术增加了扩散器的有效长度,但在相同功率密度下获得的混凝体积小于较长的扩散器。这表明增加扩散器长度和激光功率比回拉技术更能增加凝聚区。为了获得足够大的覆盖整个肿瘤的凝血区,仔细选择扩散器的长度、功率密度和回拉距离至关重要。
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Journal of engineering and science in medical diagnostics and therapy
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