Radiofrequency ablation of Hepatocellular Carcinomas lacks electrode level feature to (a) avoid the risk of thermal injury to the neighbouring organs and (b) avoid the sacrifice of normal hepatic tissue. The absence of such a feature causes additional intrusion of the human body to overcome the first problem, while there is no solution for the latter problem. An algorithm has been developed and implemented using an unconventional multi-tine RFA electrode to incur ablations specific to the shape and position of target tumours to solve these problems. Further, this algorithm can suggest the best insertion angle for the trocar, such that minimum normal tissue is sacrificed. This suggestion is made quickly with the help of a pre-simulated database. For verification of the algorithm, pre-segmented tumours have been used as inputs and damages incurred with and without algorithm have been compared.
{"title":"Algorithm to Avoid Normal Tissue Sacrifice and Thermal Injury of Neighbouring Organs During Radiofrequency Ablation of HCC Tumours Treated Using a Multi-Tine Electrode With Separately Controlled Tines","authors":"M. Dhiman, R. Repaka","doi":"10.1115/imece2021-69744","DOIUrl":"https://doi.org/10.1115/imece2021-69744","url":null,"abstract":"\u0000 Radiofrequency ablation of Hepatocellular Carcinomas lacks electrode level feature to (a) avoid the risk of thermal injury to the neighbouring organs and (b) avoid the sacrifice of normal hepatic tissue. The absence of such a feature causes additional intrusion of the human body to overcome the first problem, while there is no solution for the latter problem. An algorithm has been developed and implemented using an unconventional multi-tine RFA electrode to incur ablations specific to the shape and position of target tumours to solve these problems. Further, this algorithm can suggest the best insertion angle for the trocar, such that minimum normal tissue is sacrificed. This suggestion is made quickly with the help of a pre-simulated database. For verification of the algorithm, pre-segmented tumours have been used as inputs and damages incurred with and without algorithm have been compared.","PeriodicalId":314012,"journal":{"name":"Volume 5: Biomedical and Biotechnology","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122141781","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}
Studies have reported the susceptibility of females to cervical spine disorders under impact loading in the military and civilian populations. Inertial loading applied to the head-neck complex at its base is an example. Morphological differences exist between female and male cervical necks. The incidence of neck pain is more in the military than in the civilian populations. While use of the head supported mass is less common in the civilian populations, military personnel use head mounted devices: helmet, night vision goggles, etc. Any added head supported mass from the helmet and its attached devices adds to the in vivo head mass. This additional weight on the human head-neck system alters the load path, affects load-sharing, changes the internal forces and moments and kinematics on the osteoligamentous cervical spine column under accelerative and chronic loads. While many studies have been conducted to delineate the role of gender associated with postero-anterior Gx loading injury via experiments, clinical investigations, modeling and epidemiological research, the effect of the added head mass on segmental motions has received less attention. The objective of the study is to determine the role of the head supported mass on the segmental motions and loads on the female cervical spinal column from Gx loading applied to the base of the spine.
{"title":"Neck Motions and Loads With Head Supported Mass Under Sagittal Accelerative Loading","authors":"Yuvaraj Purushothaman, N. Yoganandan","doi":"10.1115/imece2021-72109","DOIUrl":"https://doi.org/10.1115/imece2021-72109","url":null,"abstract":"\u0000 Studies have reported the susceptibility of females to cervical spine disorders under impact loading in the military and civilian populations. Inertial loading applied to the head-neck complex at its base is an example. Morphological differences exist between female and male cervical necks. The incidence of neck pain is more in the military than in the civilian populations. While use of the head supported mass is less common in the civilian populations, military personnel use head mounted devices: helmet, night vision goggles, etc. Any added head supported mass from the helmet and its attached devices adds to the in vivo head mass. This additional weight on the human head-neck system alters the load path, affects load-sharing, changes the internal forces and moments and kinematics on the osteoligamentous cervical spine column under accelerative and chronic loads. While many studies have been conducted to delineate the role of gender associated with postero-anterior Gx loading injury via experiments, clinical investigations, modeling and epidemiological research, the effect of the added head mass on segmental motions has received less attention. The objective of the study is to determine the role of the head supported mass on the segmental motions and loads on the female cervical spinal column from Gx loading applied to the base of the spine.","PeriodicalId":314012,"journal":{"name":"Volume 5: Biomedical and Biotechnology","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130389109","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}
Much of the population have mobility disabilities. A market analysis highlighted the lack of a low-cost mobility solution that could provide terrain versatility, torso support, combined wheelchair functionality, and sit-to-stand assistance. Furthermore, the use of common, readily available parts for device life maintenance is advantageous for the intended use in rural areas. This study describes a design for a mobility solution. A simulation and analysis are performed using multi-body software to determine the interaction between the vehicle on different types of obstacles, as well as determine forces in the riskiest parts of the design for connection strength analysis. To complete this simulation, several determinations had to be obtained to use proper constraints for the system, such as the force the caregiver would push with and the damping of the tires. A physical test is performed to find the average force required to push a wheelchair and patient over outdoor, bumpy terrain. This study makes multiple suggestions for mobility device design that contrast with trending design priorities in the medical device industry and provides evidence for these recommendations. The results of the created simulations are used to make design choices regarding wheel configuration and size.
{"title":"Simulation of a Terrain Versatile Walker-Wheelchair With Torso Support","authors":"James Manzer, Gabriel Simon Sosa, D. Piovesan","doi":"10.1115/imece2021-73245","DOIUrl":"https://doi.org/10.1115/imece2021-73245","url":null,"abstract":"\u0000 Much of the population have mobility disabilities. A market analysis highlighted the lack of a low-cost mobility solution that could provide terrain versatility, torso support, combined wheelchair functionality, and sit-to-stand assistance. Furthermore, the use of common, readily available parts for device life maintenance is advantageous for the intended use in rural areas.\u0000 This study describes a design for a mobility solution. A simulation and analysis are performed using multi-body software to determine the interaction between the vehicle on different types of obstacles, as well as determine forces in the riskiest parts of the design for connection strength analysis.\u0000 To complete this simulation, several determinations had to be obtained to use proper constraints for the system, such as the force the caregiver would push with and the damping of the tires. A physical test is performed to find the average force required to push a wheelchair and patient over outdoor, bumpy terrain. This study makes multiple suggestions for mobility device design that contrast with trending design priorities in the medical device industry and provides evidence for these recommendations. The results of the created simulations are used to make design choices regarding wheel configuration and size.","PeriodicalId":314012,"journal":{"name":"Volume 5: Biomedical and Biotechnology","volume":"183 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124312555","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}
OpenSim is a free software platform that enables the user to preform interaction and movement simulations with human, animal, and robotic models. The software is accompanied by a vast user database of simulations and models which is available on the online community. By utilizing the resources available an accurate model can be created to represent any musculoskeletal configuration that happens in day-to-day activities. Forces and moments are calculated experimentally and verified by the OpenSim models for the Achilles Tendon. In this study, the muscle actuation of the Achilles Tendon is collected from multiple subjects and analyzed. Five subjects were tested for the data collection. Data was collected while the participant completed a concentric motion to ensure Achilles Tendon activation. The testing setup utilizes 3 miniature PCB accelerometers, a PCB 4-channel signal conditioner, a DAQ chassis, and a Modally Hand Impact Hammer in tandem with NI signal view express and MATLAB. Once the results from the study were analyzed, a virtual model was setup in the same configuration in OpenSim and the results from the simulation were compared to the results from the testing. The mechanical forces on the Achilles Tendon will be analyzed using the OpenSim software in order to better understand the muscle actuation at various loading levels. The proposed methods offer a non-invasive approach for studying in vivo muscle-tendon mechanics.
{"title":"Modeling the Biomechanics Parameters on Achilles Tendon Using OpenSim Simulations and Validating the Sensor Accuracy","authors":"Muhammad Salman, Zachary Contois, M. H. Tanveer","doi":"10.1115/imece2021-72108","DOIUrl":"https://doi.org/10.1115/imece2021-72108","url":null,"abstract":"\u0000 OpenSim is a free software platform that enables the user to preform interaction and movement simulations with human, animal, and robotic models. The software is accompanied by a vast user database of simulations and models which is available on the online community. By utilizing the resources available an accurate model can be created to represent any musculoskeletal configuration that happens in day-to-day activities. Forces and moments are calculated experimentally and verified by the OpenSim models for the Achilles Tendon. In this study, the muscle actuation of the Achilles Tendon is collected from multiple subjects and analyzed. Five subjects were tested for the data collection. Data was collected while the participant completed a concentric motion to ensure Achilles Tendon activation. The testing setup utilizes 3 miniature PCB accelerometers, a PCB 4-channel signal conditioner, a DAQ chassis, and a Modally Hand Impact Hammer in tandem with NI signal view express and MATLAB. Once the results from the study were analyzed, a virtual model was setup in the same configuration in OpenSim and the results from the simulation were compared to the results from the testing. The mechanical forces on the Achilles Tendon will be analyzed using the OpenSim software in order to better understand the muscle actuation at various loading levels. The proposed methods offer a non-invasive approach for studying in vivo muscle-tendon mechanics.","PeriodicalId":314012,"journal":{"name":"Volume 5: Biomedical and Biotechnology","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126087257","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}
Carotid artery is the major blood vessel which carries oxygenated blood to the brain and the face. Atherosclerosis is a major arterial disease characterized by a progressive contraction of the blood vessel. It occurs due to the deposition of cholesterol and lipids beneath the internal layer of the artery which is called stenosis. Carotid artery stenosis causes serious implications which considered one of the leading causes of morbidity and mortality in most countries. The existence of stenosis had a significant effect on the blood flow dynamic factors. Adding the arterial wall response through the wall elasticity will achieve more accurate and realistic flow characteristics. In this study, the arterial wall elasticity through two-way Fluid-Structure Interaction (FSI) was considered to the developed model to calculate the blood flow dynamics. Moreover, blood dynamic factors will be used to investigate the flow characteristics with rigid and elastic arterial wall and temporal blood responses. To estimate the blood dynamic factors, a three-dimensional reconstructed patient-specific carotid artery geometry with realistic boundary conditions is considered. Hence, a three-dimensional comprehensive model including the non-Newtonian Carreau blood flow viscosity model under pulsatile flow conditions is developed. The two-way FSI procedure was performed by applying an arbitrary Lagrangian-Eulerian (ALE) formulation to calculate the arterial response. Results indicated that using FSI has a crucial role in investigating the blood flow dynamic factors which resulted in low shear stress, pressure gradient, and velocity distribution comparing to the rigid arterial wall response. The efficient use of Computational Fluid Dynamics (CFD) has the potential to shed light on the assessment of the stenosis severity by adding the arterial wall and temporal blood response to the developed model.
{"title":"Influence of Arterial Wall Elasticity on Blood Flow Dynamic Factors of Stenotic Carotid Artery","authors":"Muhamed Albadawi, Yasser Abuouf, Mahmoudi Ahmed","doi":"10.1115/imece2021-71625","DOIUrl":"https://doi.org/10.1115/imece2021-71625","url":null,"abstract":"\u0000 Carotid artery is the major blood vessel which carries oxygenated blood to the brain and the face. Atherosclerosis is a major arterial disease characterized by a progressive contraction of the blood vessel. It occurs due to the deposition of cholesterol and lipids beneath the internal layer of the artery which is called stenosis. Carotid artery stenosis causes serious implications which considered one of the leading causes of morbidity and mortality in most countries. The existence of stenosis had a significant effect on the blood flow dynamic factors. Adding the arterial wall response through the wall elasticity will achieve more accurate and realistic flow characteristics. In this study, the arterial wall elasticity through two-way Fluid-Structure Interaction (FSI) was considered to the developed model to calculate the blood flow dynamics. Moreover, blood dynamic factors will be used to investigate the flow characteristics with rigid and elastic arterial wall and temporal blood responses. To estimate the blood dynamic factors, a three-dimensional reconstructed patient-specific carotid artery geometry with realistic boundary conditions is considered. Hence, a three-dimensional comprehensive model including the non-Newtonian Carreau blood flow viscosity model under pulsatile flow conditions is developed. The two-way FSI procedure was performed by applying an arbitrary Lagrangian-Eulerian (ALE) formulation to calculate the arterial response. Results indicated that using FSI has a crucial role in investigating the blood flow dynamic factors which resulted in low shear stress, pressure gradient, and velocity distribution comparing to the rigid arterial wall response. The efficient use of Computational Fluid Dynamics (CFD) has the potential to shed light on the assessment of the stenosis severity by adding the arterial wall and temporal blood response to the developed model.","PeriodicalId":314012,"journal":{"name":"Volume 5: Biomedical and Biotechnology","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122314192","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}
Traditional trajectory planning approaches are currently lacking in intelligence and autonomy. We used the reinforcement learning approach to solve the autonomous trajectory planning of the robot arm to avoid obstacles with uniform motion and hit the target point quickly with obstacle avoidance planning for surgical robots taken as the practical background. We used the algorithm of experience playback mechanism combined with off-policy DDPG based on reinforcement learning, and after several iterations, the robot completed trajectory planning with obstacle avoidance autonomously. Moving obstacles were added to roughly simulate the autonomous obstacle avoidance of a surgical robotic arm with moving medical personnel or mobile instruments in the operating room, based on the simple trajectory planning example of Open-AI Open-Source Project Baseline, combined with the research context. Sparse rewards were used for each iteration based on the HER algorithm, so that each attempt could gain experience. The HER-DDPG method can quickly complete the manipulator’s trajectory planning in a simulation environment, which is critical for the surgical robot’s autonomous positioning in the real world. Furthermore, the experience playback system has been tested to allow full use of sparse rewards and handle parallel tasks equally well.
{"title":"Dynamic Trajectory Planning of a 7-DOF Surgical Robot Based on HER-DDPG Algorithm","authors":"Qitao Hou, Chenchen Gu, Xiaoyu Wang, Yating Zhang, Ping Zhao","doi":"10.1115/imece2021-70294","DOIUrl":"https://doi.org/10.1115/imece2021-70294","url":null,"abstract":"\u0000 Traditional trajectory planning approaches are currently lacking in intelligence and autonomy. We used the reinforcement learning approach to solve the autonomous trajectory planning of the robot arm to avoid obstacles with uniform motion and hit the target point quickly with obstacle avoidance planning for surgical robots taken as the practical background. We used the algorithm of experience playback mechanism combined with off-policy DDPG based on reinforcement learning, and after several iterations, the robot completed trajectory planning with obstacle avoidance autonomously. Moving obstacles were added to roughly simulate the autonomous obstacle avoidance of a surgical robotic arm with moving medical personnel or mobile instruments in the operating room, based on the simple trajectory planning example of Open-AI Open-Source Project Baseline, combined with the research context. Sparse rewards were used for each iteration based on the HER algorithm, so that each attempt could gain experience. The HER-DDPG method can quickly complete the manipulator’s trajectory planning in a simulation environment, which is critical for the surgical robot’s autonomous positioning in the real world. Furthermore, the experience playback system has been tested to allow full use of sparse rewards and handle parallel tasks equally well.","PeriodicalId":314012,"journal":{"name":"Volume 5: Biomedical and Biotechnology","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128987818","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}
As human beings age, their bodies tend to deteriorate. It is the task of an engineer to counteract this natural process to ensure that humans can have a high quality of life for as long as possible. A condition that affects a wide range of people life is a discomfort and pain in the knee. This is most often caused by osteoarthritis, which occurs when the cartilage in the knee deteriorates causing the bones to rub against each other creating extreme discomfort. In this study, the attempt is to design an inexpensive and practical prosthesis to maintain and preserve the patient’s anterior cruciate ligament. The other design goals of this prosthesis are to be manufacturable and applicable by surgeons. Further, the finite element analysis has been conducted to assure the designed prosthesis can withstand the physiological loads applied on knees during daily activities.
{"title":"Design of Knee Prosthesis to Sustain ACL/PCL Ligaments and Alleviate Osteoarthritis","authors":"Peyman Honarmandi, Erwan Malki","doi":"10.1115/imece2021-72166","DOIUrl":"https://doi.org/10.1115/imece2021-72166","url":null,"abstract":"\u0000 As human beings age, their bodies tend to deteriorate. It is the task of an engineer to counteract this natural process to ensure that humans can have a high quality of life for as long as possible. A condition that affects a wide range of people life is a discomfort and pain in the knee. This is most often caused by osteoarthritis, which occurs when the cartilage in the knee deteriorates causing the bones to rub against each other creating extreme discomfort. In this study, the attempt is to design an inexpensive and practical prosthesis to maintain and preserve the patient’s anterior cruciate ligament. The other design goals of this prosthesis are to be manufacturable and applicable by surgeons. Further, the finite element analysis has been conducted to assure the designed prosthesis can withstand the physiological loads applied on knees during daily activities.","PeriodicalId":314012,"journal":{"name":"Volume 5: Biomedical and Biotechnology","volume":"146 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115741335","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}
Microwave ablation (MWA) cures cancer by inserting slender antennas into tumors and producing large amounts of heat to kill cancerous cells. A key challenge is the selective heating of cancer cells without damaging the surrounding tissue, which requires a control of heating power for appropriate temperature distribution. This study established a theoretical simulation model for the microwave ablation of a porcine liver by using a coaxial-slot antenna with 10 slots at high frequencies. The axisymmetric finite element method (FEM) with temperature dependent thermal and dielectric properties was used to describe the MWA distribution in the liver tissue by coupling the electromagnetic wave equations and the bio-heat transfer equations. The results demonstrated that the increase of microwave frequency could improve the therapeutic effect of tumor significantly since it had less collateral damage, more concentrated heated region, and better material response than conventional microwave ablations. For a spherical tumor with 10 mm of radius, the 12 GHz MWA reveals an optimum ablation performance with 21.0% of the collateral damage at the radius direction, and 5.5% of the collateral damage at the axial direction, respectively. The results show that the 12 GHz MWA produces more concentrated heat, causes the greatest difference in temperature-rise between the tumor tissues and the healthy tissues, and significantly reduces the over-treatment region for spherical tumor.
{"title":"Theoretical Evaluation of Heat Transfer in Liver Tumor Microwave Ablation Using a 10-Slot Antenna at High Frequencies","authors":"Yanbin Qin, Nanxi Li, Baolin Liu","doi":"10.1115/imece2021-73846","DOIUrl":"https://doi.org/10.1115/imece2021-73846","url":null,"abstract":"\u0000 Microwave ablation (MWA) cures cancer by inserting slender antennas into tumors and producing large amounts of heat to kill cancerous cells. A key challenge is the selective heating of cancer cells without damaging the surrounding tissue, which requires a control of heating power for appropriate temperature distribution. This study established a theoretical simulation model for the microwave ablation of a porcine liver by using a coaxial-slot antenna with 10 slots at high frequencies. The axisymmetric finite element method (FEM) with temperature dependent thermal and dielectric properties was used to describe the MWA distribution in the liver tissue by coupling the electromagnetic wave equations and the bio-heat transfer equations. The results demonstrated that the increase of microwave frequency could improve the therapeutic effect of tumor significantly since it had less collateral damage, more concentrated heated region, and better material response than conventional microwave ablations. For a spherical tumor with 10 mm of radius, the 12 GHz MWA reveals an optimum ablation performance with 21.0% of the collateral damage at the radius direction, and 5.5% of the collateral damage at the axial direction, respectively. The results show that the 12 GHz MWA produces more concentrated heat, causes the greatest difference in temperature-rise between the tumor tissues and the healthy tissues, and significantly reduces the over-treatment region for spherical tumor.","PeriodicalId":314012,"journal":{"name":"Volume 5: Biomedical and Biotechnology","volume":"40 6","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113936807","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}
A. Tamura, K. Makabe, Hatsune Yamashita, Junichi Hongu
Vascular smooth muscle cells (SMCs) in the extracellular matrix adapt to their surrounding environment in vivo with its contraction and relaxation. As blood pressure increases, the circumferential stress on the aortic wall also increases. The major components of the media are SMCs, so SMCs should regulate the vessel diameter and the mechanical balance of the aortic medial ring. Thus, it is important to clarify how external forces on SMCs are transmitted through the intracellular components. Nuclei may sense changes in the applied mechanical stretch via stress fibers (SFs) or focal adhesions (FAs). However, there is little quantitative information available about the mechanical contribution of SFs and FAs to whole-cell mechanical events such as uniaxial stretching. In the present study, therefore, we developed a finite element model of a cultured SMC, with contractile SFs, on a silicone substrate, and applied a uniaxial stretch, to investigate the mechanotransduction pathways involved in SMCs. We revealed that the initial orientation angle of the SFs was closely correlated with their resultant stretch, and the magnitude of the biomechanical force exerted by SFs.
{"title":"Finite Element Model of a Cultured Vascular Smooth Muscle Cell Subjected to Uniaxial Stretch: Effect of Orientation Angle of Stress Fibers on Biomechanical Responses","authors":"A. Tamura, K. Makabe, Hatsune Yamashita, Junichi Hongu","doi":"10.1115/imece2021-68844","DOIUrl":"https://doi.org/10.1115/imece2021-68844","url":null,"abstract":"Vascular smooth muscle cells (SMCs) in the extracellular matrix adapt to their surrounding environment in vivo with its contraction and relaxation. As blood pressure increases, the circumferential stress on the aortic wall also increases. The major components of the media are SMCs, so SMCs should regulate the vessel diameter and the mechanical balance of the aortic medial ring.\u0000 Thus, it is important to clarify how external forces on SMCs are transmitted through the intracellular components. Nuclei may sense changes in the applied mechanical stretch via stress fibers (SFs) or focal adhesions (FAs). However, there is little quantitative information available about the mechanical contribution of SFs and FAs to whole-cell mechanical events such as uniaxial stretching.\u0000 In the present study, therefore, we developed a finite element model of a cultured SMC, with contractile SFs, on a silicone substrate, and applied a uniaxial stretch, to investigate the mechanotransduction pathways involved in SMCs. We revealed that the initial orientation angle of the SFs was closely correlated with their resultant stretch, and the magnitude of the biomechanical force exerted by SFs.","PeriodicalId":314012,"journal":{"name":"Volume 5: Biomedical and Biotechnology","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131980616","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}
In this paper, an investigation into the dynamics flow behaviour of a humidifier unit is carried out using the numerical simulation method. The Computational Aeroacoustics (CAA) with a hybrid approach is conducted in the ANSYS software environment. The CFD simulations were used to investigate the internal flow behaviours of the humification fluid model. The predicted results have shown the internal flow characteristics combined with scatters, circulations, and separation behaviours. These behaviours are due to the installation of a baffle unit inside the humification unit. Turbulent and pressure fluctuations were used to predict the noise level generated within the system. The predicted results are compared with the experimental results for validation. The comparison shows the predicted results agreed with the experimental result with some differences in frequency analysis. In summary, the numerical model was developed for the CPAP humidifier unit to study the internal flow behaviours and the potential noise source location. The predicted results have explained and identified some locations of interest. These findings were used as guidelines to optimise and further develop to improve the future product. It also concludes that the CAA approach can be considered as a potential cost-effective tool in the early product development process for a better product design.
{"title":"Computational Modeling and Analysis of Turbulent Flows in the Humidification Unit of the Continuous Positive Airways Pressure Device","authors":"T. Vuong, A. Al-Jumaily","doi":"10.1115/imece2021-68573","DOIUrl":"https://doi.org/10.1115/imece2021-68573","url":null,"abstract":"\u0000 In this paper, an investigation into the dynamics flow behaviour of a humidifier unit is carried out using the numerical simulation method. The Computational Aeroacoustics (CAA) with a hybrid approach is conducted in the ANSYS software environment.\u0000 The CFD simulations were used to investigate the internal flow behaviours of the humification fluid model. The predicted results have shown the internal flow characteristics combined with scatters, circulations, and separation behaviours. These behaviours are due to the installation of a baffle unit inside the humification unit. Turbulent and pressure fluctuations were used to predict the noise level generated within the system. The predicted results are compared with the experimental results for validation. The comparison shows the predicted results agreed with the experimental result with some differences in frequency analysis.\u0000 In summary, the numerical model was developed for the CPAP humidifier unit to study the internal flow behaviours and the potential noise source location. The predicted results have explained and identified some locations of interest. These findings were used as guidelines to optimise and further develop to improve the future product. It also concludes that the CAA approach can be considered as a potential cost-effective tool in the early product development process for a better product design.","PeriodicalId":314012,"journal":{"name":"Volume 5: Biomedical and Biotechnology","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129073594","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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