Pub Date : 2023-02-01Epub Date: 2022-11-01DOI: 10.1115/1.4055877
John L Cashin, Alex J Wirtz, Guy M Genin, Mohamed Zayed
In aortoiliac occlusive disease, atherosclerotic plaques can occlude the distal aortic bifurcation and proximal bilateral iliac artery and thus cause ischemia in the lower extremity. This is typically treated by restoring patency with balloon expandable stents. Stents are typically deployed in a "kissing stent" configuration into the bilateral iliac arteries and into the distal aortic bifurcation lumen to restore antegrade arterial flow. However, these stents typically become re-occluded by plaques. To understand the reasons for this and look for solutions, we simulated flow dynamics in the aortic bifurcation in the presence and absence of stents using computational fluid dynamics. Results demonstrated that the kissing stent configuration was associated with high levels of vorticity and flow constriction. These prothrombotic variables were alleviated in an alternative, aortoiliac fenestrated (AIFEN), tapered, and balloon-expandable stent design. Our findings suggest that stent design can be tailored to improve flow fields for aortoiliac stenting.
{"title":"A Fenestrated Balloon Expandable Stent System for the Treatment of Aortoiliac Occlusive Disease.","authors":"John L Cashin, Alex J Wirtz, Guy M Genin, Mohamed Zayed","doi":"10.1115/1.4055877","DOIUrl":"https://doi.org/10.1115/1.4055877","url":null,"abstract":"<p><p>In aortoiliac occlusive disease, atherosclerotic plaques can occlude the distal aortic bifurcation and proximal bilateral iliac artery and thus cause ischemia in the lower extremity. This is typically treated by restoring patency with balloon expandable stents. Stents are typically deployed in a \"kissing stent\" configuration into the bilateral iliac arteries and into the distal aortic bifurcation lumen to restore antegrade arterial flow. However, these stents typically become re-occluded by plaques. To understand the reasons for this and look for solutions, we simulated flow dynamics in the aortic bifurcation in the presence and absence of stents using computational fluid dynamics. Results demonstrated that the kissing stent configuration was associated with high levels of vorticity and flow constriction. These prothrombotic variables were alleviated in an alternative, aortoiliac fenestrated (AIFEN), tapered, and balloon-expandable stent design. Our findings suggest that stent design can be tailored to improve flow fields for aortoiliac stenting.</p>","PeriodicalId":73734,"journal":{"name":"Journal of engineering and science in medical diagnostics and therapy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9635567/pdf/jesmdt-22-1015_011004.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"40463416","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}
Basketball players' visual and neurological characteristics may affect their sports performance. In this paper, 20 basketball players and 20 non-athletes received a motion vision test and a neurological efficiency test. The experimental stimulus was to determine whether there was a ball on the picture. The relevant visual data were obtained by an eye tracker. The brain area activity data were obtained by functional magnetic resonance imaging (fMRI). The data were processed and analyzed. The results showed that the reaction time of group A (basketball players) was 526.78 ± 75.36 ms, and the correct rate was 94.12 ± 3.45%, both of which were better than group B (non-athletes). The fixation duration and fixation frequency of group A were 204.77 ± 40.23 ms and 1.67 ± 0.41 times, suggesting good fixation stability, and group A activated fewer brain areas than group B. The experimental results verify that basketball players have better target capture ability and higher neural efficiency while consuming fewer neural resources.
{"title":"Effects of Motion Vision and Neural Efficiency On Target Capture in Basketball Players","authors":"Xianghui Li","doi":"10.1115/1.4056607","DOIUrl":"https://doi.org/10.1115/1.4056607","url":null,"abstract":"\u0000 Basketball players' visual and neurological characteristics may affect their sports performance. In this paper, 20 basketball players and 20 non-athletes received a motion vision test and a neurological efficiency test. The experimental stimulus was to determine whether there was a ball on the picture. The relevant visual data were obtained by an eye tracker. The brain area activity data were obtained by functional magnetic resonance imaging (fMRI). The data were processed and analyzed. The results showed that the reaction time of group A (basketball players) was 526.78 ± 75.36 ms, and the correct rate was 94.12 ± 3.45%, both of which were better than group B (non-athletes). The fixation duration and fixation frequency of group A were 204.77 ± 40.23 ms and 1.67 ± 0.41 times, suggesting good fixation stability, and group A activated fewer brain areas than group B. The experimental results verify that basketball players have better target capture ability and higher neural efficiency while consuming fewer neural resources.","PeriodicalId":73734,"journal":{"name":"Journal of engineering and science in medical diagnostics and therapy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81040683","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}
Radiofrequency ablation (RFA) of the medial branch nerve is a widely used therapeutic intervention for back pain originating from the facet joint. However, multifidus denervation is a well-known adverse effect of this RFA procedure. Computational simulations of RFA can be used to design a new multifidus-sparing RFA procedure for facet joint pain. Unfortunately, there is not a computational model available for RFA of porcine spines (a common animal model for the translation of spinal treatments). The objective of this study is to develop and verify a computational model for bipolar radiofrequency ablation of porcine spine muscle. To do this, the electrical and thermal conductivity properties were measured over a temperature range of 20 °C to 90 °C in ex-vivo porcine spinal. A proportional, integral, and derivative (PID) controlled finite element (FE) model was developed and tuned to simulate the ablation process. Finally, tissue temperatures from simulations and experimental ablations were compared. Thermal conductivity values of spinal muscle ranged from 0.33 W/mK to 0.57 W/mK. Similarly, electrical conductivity varied from 0.36 S/m to 1.28 S/m. The tuned PID parameters for temperature-controlled model were Kp=40, Ki=0.01, and Kd=0. A close agreement between experimental measurements of tissue temperature and simulations were observed in the uncertainty range with R-squared values between 0.88 and 0.98. The model developed in this study is a valuable tool for preclinical studies exploring new RFA methods of spinal nerves.
{"title":"Finite Element Simulation of Pid-Controlled Bipolar Radiofrequency Ablation of Porcine Spinal Muscle","authors":"H. Kumru, A. Attaluri, V. Gordin, Daniel C Cortes","doi":"10.1115/1.4056516","DOIUrl":"https://doi.org/10.1115/1.4056516","url":null,"abstract":"\u0000 Radiofrequency ablation (RFA) of the medial branch nerve is a widely used therapeutic intervention for back pain originating from the facet joint. However, multifidus denervation is a well-known adverse effect of this RFA procedure. Computational simulations of RFA can be used to design a new multifidus-sparing RFA procedure for facet joint pain. Unfortunately, there is not a computational model available for RFA of porcine spines (a common animal model for the translation of spinal treatments). The objective of this study is to develop and verify a computational model for bipolar radiofrequency ablation of porcine spine muscle. To do this, the electrical and thermal conductivity properties were measured over a temperature range of 20 °C to 90 °C in ex-vivo porcine spinal. A proportional, integral, and derivative (PID) controlled finite element (FE) model was developed and tuned to simulate the ablation process. Finally, tissue temperatures from simulations and experimental ablations were compared. Thermal conductivity values of spinal muscle ranged from 0.33 W/mK to 0.57 W/mK. Similarly, electrical conductivity varied from 0.36 S/m to 1.28 S/m. The tuned PID parameters for temperature-controlled model were Kp=40, Ki=0.01, and Kd=0. A close agreement between experimental measurements of tissue temperature and simulations were observed in the uncertainty range with R-squared values between 0.88 and 0.98. The model developed in this study is a valuable tool for preclinical studies exploring new RFA methods of spinal nerves.","PeriodicalId":73734,"journal":{"name":"Journal of engineering and science in medical diagnostics and therapy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88364399","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 (MA) has emerged as a better and more promising alternative to medicate the primitive stage of cancer. Major advantages of MA include the organ-specific treatment and the prospect of treating ≥ 3 cm diameter tumors with minimal pain and nominal cost. Past studies suggest that tissue properties and input parameters play a vital role during the MA process. Hence, an in-depth study has been made to inspect the influence of these crucial parameters as follows, applied power, perfusion rate of blood, frequency, thermal conductivity, electrical conductivity, and, relative permittivity on the dimension of ablation zone attained while treating with MA on Lungs. The FEM-based analysis with a numerical approach is taken into account to signify the individual impact of the parameters on the ablation volume. Using the statistical tool, a regression equation was formulated and the data derived from the Taguchi L27 orthogonal array helped to get the maximized ablation zone. The results infer that the applied power has a remarkable effect on the response with a positive correlation. Along with the power, frequency, and blood perfusion rate were also observed to influence the treatment process significantly. The following optimal settings Power3, Frequency3, Blood Perfusion Rate3, Electrical Conductivity3, Thermal Conductivity2, and Relative Permittivity2 were found out along with the maximized ablation volume of 14.35 mm3. The results obtained from the present work would be highly helpful for the radiologist and the clinical practitioners to get pre-treatment data during the initial phase.
{"title":"Analysis and Optimization of Crucial Factors Affecting Efficacy of Microwave Ablation","authors":"Shubhamshree Avishek, S. Samantaray","doi":"10.1115/1.4056409","DOIUrl":"https://doi.org/10.1115/1.4056409","url":null,"abstract":"\u0000 Microwave Ablation (MA) has emerged as a better and more promising alternative to medicate the primitive stage of cancer. Major advantages of MA include the organ-specific treatment and the prospect of treating ≥ 3 cm diameter tumors with minimal pain and nominal cost. Past studies suggest that tissue properties and input parameters play a vital role during the MA process. Hence, an in-depth study has been made to inspect the influence of these crucial parameters as follows, applied power, perfusion rate of blood, frequency, thermal conductivity, electrical conductivity, and, relative permittivity on the dimension of ablation zone attained while treating with MA on Lungs. The FEM-based analysis with a numerical approach is taken into account to signify the individual impact of the parameters on the ablation volume. Using the statistical tool, a regression equation was formulated and the data derived from the Taguchi L27 orthogonal array helped to get the maximized ablation zone. The results infer that the applied power has a remarkable effect on the response with a positive correlation. Along with the power, frequency, and blood perfusion rate were also observed to influence the treatment process significantly. The following optimal settings Power3, Frequency3, Blood Perfusion Rate3, Electrical Conductivity3, Thermal Conductivity2, and Relative Permittivity2 were found out along with the maximized ablation volume of 14.35 mm3. The results obtained from the present work would be highly helpful for the radiologist and the clinical practitioners to get pre-treatment data during the initial phase.","PeriodicalId":73734,"journal":{"name":"Journal of engineering and science in medical diagnostics and therapy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88218634","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) is a minimally invasive thermal ablation technique that has the advantages of obtaining high intratumoral temperatures, less treatment time and large ablation region as compared to other thermal ablation techniques. The ablation region obtained during MWA procedure mainly depends on the design and type of the trocar being used. The trocar plays an essential role in the MWA system by governing the energy distribution during tissue ablation. In this study, a novel MWA trocar design has been considered to achieve concentrated ablation region along the tumor's spatial distribution. A dual tine trocar with each tine supplied with energy at different frequencies (2.45 GHz and 6 GHz) has been considered for tumor ablation. Commercially available Finite Element based software has been used (COMSOL-Multiphysics) to analyze the extent of ablation zone. Coupled bioheat and electromagnetic physics interfaces have been utilized. Results showed that the proposed trocar with tines operating at 6 GHz on both the tines leads to a large ablation region (3 cm in diameter) with spherical in shape. Irregularly shaped ablation region can also be achieved by this trocar with tines operating at different frequencies. The minimum time required for complete tumor ablation by the trocar operated at 6 GHz is 4 minutes, followed by 6 minutes for the trocar operated at 2.45 GHz. The proposed trocar can become a part of a better treatment planning system (TPS) based on tumor shape, nearby blood vessel presence, and the trocar's precise insertion.
{"title":"Microwave Ablation Trocar Operated At Dual Tine Dual-frequency: A Numerical Analysis","authors":"Satish Vellavalapalli, R. Repaka","doi":"10.1115/1.4056410","DOIUrl":"https://doi.org/10.1115/1.4056410","url":null,"abstract":"\u0000 Microwave ablation (MWA) is a minimally invasive thermal ablation technique that has the advantages of obtaining high intratumoral temperatures, less treatment time and large ablation region as compared to other thermal ablation techniques. The ablation region obtained during MWA procedure mainly depends on the design and type of the trocar being used. The trocar plays an essential role in the MWA system by governing the energy distribution during tissue ablation. In this study, a novel MWA trocar design has been considered to achieve concentrated ablation region along the tumor's spatial distribution. A dual tine trocar with each tine supplied with energy at different frequencies (2.45 GHz and 6 GHz) has been considered for tumor ablation. Commercially available Finite Element based software has been used (COMSOL-Multiphysics) to analyze the extent of ablation zone. Coupled bioheat and electromagnetic physics interfaces have been utilized. Results showed that the proposed trocar with tines operating at 6 GHz on both the tines leads to a large ablation region (3 cm in diameter) with spherical in shape. Irregularly shaped ablation region can also be achieved by this trocar with tines operating at different frequencies. The minimum time required for complete tumor ablation by the trocar operated at 6 GHz is 4 minutes, followed by 6 minutes for the trocar operated at 2.45 GHz. The proposed trocar can become a part of a better treatment planning system (TPS) based on tumor shape, nearby blood vessel presence, and the trocar's precise insertion.","PeriodicalId":73734,"journal":{"name":"Journal of engineering and science in medical diagnostics and therapy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86015135","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}
Viscoelasticity of the spinal nerve roots may play a significant role in predicting nerve root damage caused by overall spinal motion. However, only a few studies have investigated the complex mechanical behavior of this tissue. The current study presents a theoretical protocol for predicting mechanical responses of soft biological materials, and this method was used to a uniaxially stretched neural fiber bundle isolated from porcine spinal nerve roots with various loading configurations. Stress relaxation tests were performed to systematically determine a set of parameters dictating the stress decaying process, i.e., a set of relaxation moduli and the corresponding time constants. Based on the obtained experimental and numerical test data, it was confirmed that the proposed method is effective even for the prediction of mechanical response to a cyclic stretch immediately after the ramp-hold test. In addition, an elastic response, i.e., a stress-strain relationship under a high-rate loading regime, was determined analytically. The results demonstrated that instantaneous mechanical responses of neural fiber bundles can be stiffened against very rapid stretch (>10 s-1); however, the fibers are relatively insensitive to moderate loading rates (<1 s-1). The ultimate tensile strength was estimated to be approximately 8 MPa at the structural failure strain (15%). This information will enable the computational assessment of traumatic nerve root injuries sustained during traffic accidents and contact sports.
{"title":"Prediction of Mechanical Responses of a Uniaxially Stretched Neural Fiber Bundle: Theoretical Approach for a Traumatic Loading Condition","authors":"A. Tamura, Junichi Hongu","doi":"10.1115/1.4056304","DOIUrl":"https://doi.org/10.1115/1.4056304","url":null,"abstract":"\u0000 Viscoelasticity of the spinal nerve roots may play a significant role in predicting nerve root damage caused by overall spinal motion. However, only a few studies have investigated the complex mechanical behavior of this tissue. The current study presents a theoretical protocol for predicting mechanical responses of soft biological materials, and this method was used to a uniaxially stretched neural fiber bundle isolated from porcine spinal nerve roots with various loading configurations. Stress relaxation tests were performed to systematically determine a set of parameters dictating the stress decaying process, i.e., a set of relaxation moduli and the corresponding time constants. Based on the obtained experimental and numerical test data, it was confirmed that the proposed method is effective even for the prediction of mechanical response to a cyclic stretch immediately after the ramp-hold test. In addition, an elastic response, i.e., a stress-strain relationship under a high-rate loading regime, was determined analytically. The results demonstrated that instantaneous mechanical responses of neural fiber bundles can be stiffened against very rapid stretch (>10 s-1); however, the fibers are relatively insensitive to moderate loading rates (<1 s-1). The ultimate tensile strength was estimated to be approximately 8 MPa at the structural failure strain (15%). This information will enable the computational assessment of traumatic nerve root injuries sustained during traffic accidents and contact sports.","PeriodicalId":73734,"journal":{"name":"Journal of engineering and science in medical diagnostics and therapy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88860363","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}
Z. Hao, Md. Mahfuzur Rahman, J. Au, Chloe E Athaide, L. Jutlah
As compared with its radial wall displacement, axial wall displacement at the common carotid artery (CCA) carries independent clinical values, but its physical mechanisms are unclear. This study aims to investigate whether axial wall displacement at the CCA is solely from Young waves. A pulse wave propagation theory is utilized to identify two types of waves, Young waves and Lamb waves, in an artery, and identifies two sources for axial wall displacement, wall shear stress and radial wall displacement gradient with a factor of the difference between axial and circumferential initial tension, which reveals the influence of axial initial tension on the waveform of axial wall displacement. Theoretical expressions are derived for calculating the waveforms of axial wall displacement and its two sources in the Young waves. With the measured pulsatile pressure and blood velocity at the CA of three healthy adults as the inputs, the waveforms of axial wall displacement in the Young waves are calculated at different values of axial initial tension, and are found to greatly differ from their measured counterparts. As such, the Lamb waves may contribute to axial wall displacement at the CCA and the associated physical and physiological implications are discussed. Given the clinical values of axial wall displacement at the CCA, the Lamb waves may play a non-negligible role in determining arterial health and needs to be further studied for a comprehensive assessment of arterial wall mechanics.
{"title":"Axial Wall Displacement At the Common Carotid Artery is Associated with the Lamb Waves","authors":"Z. Hao, Md. Mahfuzur Rahman, J. Au, Chloe E Athaide, L. Jutlah","doi":"10.1115/1.4056267","DOIUrl":"https://doi.org/10.1115/1.4056267","url":null,"abstract":"\u0000 As compared with its radial wall displacement, axial wall displacement at the common carotid artery (CCA) carries independent clinical values, but its physical mechanisms are unclear. This study aims to investigate whether axial wall displacement at the CCA is solely from Young waves. A pulse wave propagation theory is utilized to identify two types of waves, Young waves and Lamb waves, in an artery, and identifies two sources for axial wall displacement, wall shear stress and radial wall displacement gradient with a factor of the difference between axial and circumferential initial tension, which reveals the influence of axial initial tension on the waveform of axial wall displacement. Theoretical expressions are derived for calculating the waveforms of axial wall displacement and its two sources in the Young waves. With the measured pulsatile pressure and blood velocity at the CA of three healthy adults as the inputs, the waveforms of axial wall displacement in the Young waves are calculated at different values of axial initial tension, and are found to greatly differ from their measured counterparts. As such, the Lamb waves may contribute to axial wall displacement at the CCA and the associated physical and physiological implications are discussed. Given the clinical values of axial wall displacement at the CCA, the Lamb waves may play a non-negligible role in determining arterial health and needs to be further studied for a comprehensive assessment of arterial wall mechanics.","PeriodicalId":73734,"journal":{"name":"Journal of engineering and science in medical diagnostics and therapy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81444222","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}
Type I diabetes is a chronic disease in which insulin is not adequately produced by the pancreatic β-cells, which leads to a high glucose concentration. In practice, external Insulin delivery is the only method to deal with this disease. To this end, a multi-objective optimal control for insulin delivery is introduced in this paper. Three conflicting objectives are considered: minimizing the risk of hypoglycemia and hyperglycemia, and reducing the amount of injected insulin. These objectives are simultaneously minimized while tuning the closed-loop system parameters that include the design details of the linear-quadratic regulator(LQR) and estimator speed of convergence. The lower and upper bounds of the LQR setup parameters are determined by Bryson's rule taking into account the nominal glucose range (70 – 160 mg/dL) and maximum and minimum pump infusion rates (0.0024 –15 mU/min). The lower and upper bounds of the estimator convergence speed are chosen such that the estimator is faster than the fastest mode of the closed-loop system. For computer simulations, Bergman's minimal model, which is one of the commonly used models, is employed to simulate glucose-insulin dynamics in Type-I diabetic patients. The non-dominated sorting genetic algorithm (NSGA-II) solves the optimization problem, one of the widely used algorithms in solving multi-objective optimization problems (MOPs). The optimal solutions in terms of the Pareto set and its image, the Pareto front, are obtained and analyzed. The results show that the MOP solution introduces many optimal options from which the decision-maker can choose to implement. Furthermore, under high initial glucose levels, parametric variations of Bergman's model, and external disturbance; the optimal control performance is tested to show that the system can bring glucose levels quickly to the desired value regardless of high initial glucose concentrations, can efficiently work for different patients, and is robust against irregular snacks or meals.
{"title":"Multi-Objective Optimal Regulation of Glucose Concentration in Type I Diabetes Mellitus","authors":"Raya Abushaker, Y. Sardahi, Ahmad M. Alshorman","doi":"10.1115/1.4056176","DOIUrl":"https://doi.org/10.1115/1.4056176","url":null,"abstract":"\u0000 Type I diabetes is a chronic disease in which insulin is not adequately produced by the pancreatic β-cells, which leads to a high glucose concentration. In practice, external Insulin delivery is the only method to deal with this disease. To this end, a multi-objective optimal control for insulin delivery is introduced in this paper. Three conflicting objectives are considered: minimizing the risk of hypoglycemia and hyperglycemia, and reducing the amount of injected insulin. These objectives are simultaneously minimized while tuning the closed-loop system parameters that include the design details of the linear-quadratic regulator(LQR) and estimator speed of convergence. The lower and upper bounds of the LQR setup parameters are determined by Bryson's rule taking into account the nominal glucose range (70 – 160 mg/dL) and maximum and minimum pump infusion rates (0.0024 –15 mU/min). The lower and upper bounds of the estimator convergence speed are chosen such that the estimator is faster than the fastest mode of the closed-loop system. For computer simulations, Bergman's minimal model, which is one of the commonly used models, is employed to simulate glucose-insulin dynamics in Type-I diabetic patients. The non-dominated sorting genetic algorithm (NSGA-II) solves the optimization problem, one of the widely used algorithms in solving multi-objective optimization problems (MOPs). The optimal solutions in terms of the Pareto set and its image, the Pareto front, are obtained and analyzed. The results show that the MOP solution introduces many optimal options from which the decision-maker can choose to implement. Furthermore, under high initial glucose levels, parametric variations of Bergman's model, and external disturbance; the optimal control performance is tested to show that the system can bring glucose levels quickly to the desired value regardless of high initial glucose concentrations, can efficiently work for different patients, and is robust against irregular snacks or meals.","PeriodicalId":73734,"journal":{"name":"Journal of engineering and science in medical diagnostics and therapy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77541735","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-11-01Epub Date: 2022-07-07DOI: 10.1115/1.4054856
Yuvaraj Purushothaman, Narayan Yoganandan
While many studies have been conducted to delineate the role of gender in rear impact 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 cervical spinal column from rear impact loading. The study used finite element modeling. The model was subjected to mesh convergence studies. It was validated with human cadaver experimental data by applying the rear impact acceleration pulse to the base of the spine. At all levels of the subaxial spinal column, a comparison was made between male and female spines and with and without the use of an army combat helmet. For this purpose, segmental motions, forces, and bending moments were used as biomechanical parameters. Results showed that female spines responded with increased motions than males, and the presence of a helmet increased motions and loads in males and female spines at all levels. Numerical data are given. Head supported mass affects spine responses at all levels. The present computational modeling study, from one geometry for the male spine and one geometry for the female spine (limitations are addressed in the paper), provided insights into the mechanisms of the internal load transfer with the presence of head supported mass, prevalent in certain civilian occupations and active-duty Service members in the military.
{"title":"Gender Differences in Cervical Spine Motions and Loads With Head Supported Mass Using Finite Element Models.","authors":"Yuvaraj Purushothaman, Narayan Yoganandan","doi":"10.1115/1.4054856","DOIUrl":"https://doi.org/10.1115/1.4054856","url":null,"abstract":"<p><p>While many studies have been conducted to delineate the role of gender in rear impact 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 cervical spinal column from rear impact loading. The study used finite element modeling. The model was subjected to mesh convergence studies. It was validated with human cadaver experimental data by applying the rear impact acceleration pulse to the base of the spine. At all levels of the subaxial spinal column, a comparison was made between male and female spines and with and without the use of an army combat helmet. For this purpose, segmental motions, forces, and bending moments were used as biomechanical parameters. Results showed that female spines responded with increased motions than males, and the presence of a helmet increased motions and loads in males and female spines at all levels. Numerical data are given. Head supported mass affects spine responses at all levels. The present computational modeling study, from one geometry for the male spine and one geometry for the female spine (limitations are addressed in the paper), provided insights into the mechanisms of the internal load transfer with the presence of head supported mass, prevalent in certain civilian occupations and active-duty Service members in the military.</p>","PeriodicalId":73734,"journal":{"name":"Journal of engineering and science in medical diagnostics and therapy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9341196/pdf/jesmdt-22-1001_041004.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"40454224","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}
Pub Date : 2022-11-01Epub Date: 2022-05-11DOI: 10.1115/1.4054386
Jacob Herrmann, Michaela Kollisch-Singule, Joshua Satalin, Gary F Nieman, David W Kaczka
The mammalian lung is characterized by heterogeneity in both its structure and function, by incorporating an asymmetric branching airway tree optimized for maintenance of efficient ventilation, perfusion, and gas exchange. Despite potential benefits of naturally occurring heterogeneity in the lungs, there may also be detrimental effects arising from pathologic processes, which may result in deficiencies in gas transport and exchange. Regardless of etiology, pathologic heterogeneity results in the maldistribution of regional ventilation and perfusion, impairments in gas exchange, and increased work of breathing. In extreme situations, heterogeneity may result in respiratory failure, necessitating support with a mechanical ventilator. This review will present a summary of measurement techniques for assessing and quantifying heterogeneity in respiratory system structure and function during mechanical ventilation. These methods have been grouped according to four broad categories: (1) inverse modeling of heterogeneous mechanical function; (2) capnography and washout techniques to measure heterogeneity of gas transport; (3) measurements of heterogeneous deformation on the surface of the lung; and finally (4) imaging techniques used to observe spatially-distributed ventilation or regional deformation. Each technique varies with regard to spatial and temporal resolution, degrees of invasiveness, risks posed to patients, as well as suitability for clinical implementation. Nonetheless, each technique provides a unique perspective on the manifestations and consequences of mechanical heterogeneity in the diseased lung.
{"title":"Assessment of Heterogeneity in Lung Structure and Function During Mechanical Ventilation: A Review of Methodologies.","authors":"Jacob Herrmann, Michaela Kollisch-Singule, Joshua Satalin, Gary F Nieman, David W Kaczka","doi":"10.1115/1.4054386","DOIUrl":"https://doi.org/10.1115/1.4054386","url":null,"abstract":"<p><p>The mammalian lung is characterized by heterogeneity in both its structure and function, by incorporating an asymmetric branching airway tree optimized for maintenance of efficient ventilation, perfusion, and gas exchange. Despite potential benefits of naturally occurring heterogeneity in the lungs, there may also be detrimental effects arising from pathologic processes, which may result in deficiencies in gas transport and exchange. Regardless of etiology, pathologic heterogeneity results in the maldistribution of regional ventilation and perfusion, impairments in gas exchange, and increased work of breathing. In extreme situations, heterogeneity may result in respiratory failure, necessitating support with a mechanical ventilator. This review will present a summary of measurement techniques for assessing and quantifying heterogeneity in respiratory system structure and function during mechanical ventilation. These methods have been grouped according to four broad categories: (1) inverse modeling of heterogeneous mechanical function; (2) capnography and washout techniques to measure heterogeneity of gas transport; (3) measurements of heterogeneous deformation on the surface of the lung; and finally (4) imaging techniques used to observe spatially-distributed ventilation or regional deformation. Each technique varies with regard to spatial and temporal resolution, degrees of invasiveness, risks posed to patients, as well as suitability for clinical implementation. Nonetheless, each technique provides a unique perspective on the manifestations and consequences of mechanical heterogeneity in the diseased lung.</p>","PeriodicalId":73734,"journal":{"name":"Journal of engineering and science in medical diagnostics and therapy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9132008/pdf/jesmdt-21-1060_040801.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"40520191","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}
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