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.
{"title":"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","authors":"Rodward L. Hewlin, Maegan Edwards, Michael Smith","doi":"10.1115/1.4062571","DOIUrl":"https://doi.org/10.1115/1.4062571","url":null,"abstract":"\u0000 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.","PeriodicalId":73734,"journal":{"name":"Journal of engineering and science in medical diagnostics and therapy","volume":"27 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89862560","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}
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.
{"title":"Design and Development of Patient-specific Miniplate for the Treatment of Maxillofacial Fractures-A Finite Element Study","authors":"Sandeep Choudhury, Anik Banerjee, S. Majumder, A. Roychowdhury","doi":"10.1115/1.4062509","DOIUrl":"https://doi.org/10.1115/1.4062509","url":null,"abstract":"\u0000 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.","PeriodicalId":73734,"journal":{"name":"Journal of engineering and science in medical diagnostics and therapy","volume":"51 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84526074","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}
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.
{"title":"Is It Feasible to Reconstruct Aortic Pressure Waveform Based On a 1d Uniform Model of the Arterial Tree?","authors":"Z. Hao","doi":"10.1115/1.4062468","DOIUrl":"https://doi.org/10.1115/1.4062468","url":null,"abstract":"\u0000 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.","PeriodicalId":73734,"journal":{"name":"Journal of engineering and science in medical diagnostics and therapy","volume":"54 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84722848","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}
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.
{"title":"Measurement of Brain Strains in a Goat Head Under Impact Loading","authors":"Abhilash Singh, Y. Naing, S. Ganpule","doi":"10.1115/1.4062467","DOIUrl":"https://doi.org/10.1115/1.4062467","url":null,"abstract":"\u0000 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.","PeriodicalId":73734,"journal":{"name":"Journal of engineering and science in medical diagnostics and therapy","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72729640","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}
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.
{"title":"Decoupling Uniaxial Tensile Prestress and Waveguide Effects From Estimates of the Complex Shear Modulus in a Cylindrical Structure Using Transverse-Polarized Dynamic Elastography.","authors":"Melika Salehabadi, Joseph Crutison, Dieter Klatt, Thomas J Royston","doi":"10.1115/1.4056411","DOIUrl":"https://doi.org/10.1115/1.4056411","url":null,"abstract":"<p><p>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.</p>","PeriodicalId":73734,"journal":{"name":"Journal of engineering and science in medical diagnostics and therapy","volume":"6 2","pages":"021003"},"PeriodicalIF":0.0,"publicationDate":"2023-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9793439/pdf/jesmdt-22-1030_021003.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10833469","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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.
{"title":"Biomechanical Analysis of Mandibular Bone-Implant Construct with Three Implant Screw Design: A Finite Element Study","authors":"Anik Banerjee, Sandeep Choudhury, Masud Rana, Arindam Chakraborty, Abhisek Gupta, A. Chowdhury","doi":"10.1115/1.4062437","DOIUrl":"https://doi.org/10.1115/1.4062437","url":null,"abstract":"\u0000 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.","PeriodicalId":73734,"journal":{"name":"Journal of engineering and science in medical diagnostics and therapy","volume":"35 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73418642","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 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.
{"title":"Tissue Growth Model for Maintaining Tensional Homeostasis with Applications to Hypertension and Stented Artery","authors":"Pengfei Dong, K. Nunes, Linxia Gu","doi":"10.1115/1.4062387","DOIUrl":"https://doi.org/10.1115/1.4062387","url":null,"abstract":"\u0000 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.","PeriodicalId":73734,"journal":{"name":"Journal of engineering and science in medical diagnostics and therapy","volume":"23 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79078006","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}
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.
{"title":"Evaluating the in Vitro Mechanical Responses of Stem Cell Under Fluid Perfusion in Different Porous Scaffolds","authors":"S. Majumder, Abhisek Gupta, Sandeep Choudhury, Amit Roy Chowdhury","doi":"10.1115/1.4062340","DOIUrl":"https://doi.org/10.1115/1.4062340","url":null,"abstract":"\u0000 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.","PeriodicalId":73734,"journal":{"name":"Journal of engineering and science in medical diagnostics and therapy","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75773946","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 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.
{"title":"Design and Implementation of a Behavioral Sequence Framework for Human-robot Interaction Utilizing Brain-computer Interface and Haptic Feedback","authors":"Sudip Hazra, Shane Whitaker, P. Shiakolas","doi":"10.1115/1.4062341","DOIUrl":"https://doi.org/10.1115/1.4062341","url":null,"abstract":"\u0000 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.","PeriodicalId":73734,"journal":{"name":"Journal of engineering and science in medical diagnostics and therapy","volume":"55 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77850623","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}
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.
{"title":"A Computational Study Evaluating the Effects of Diffuser Length and Pullback Distance on the Ablation Zone During Laser Ablation Treatment of Liver Cancer","authors":"Zhi Q. Tan, E. Ooi, E. Ooi","doi":"10.1115/1.4062246","DOIUrl":"https://doi.org/10.1115/1.4062246","url":null,"abstract":"\u0000 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.","PeriodicalId":73734,"journal":{"name":"Journal of engineering and science in medical diagnostics and therapy","volume":"53 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81124426","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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