Flow patterns are investigated in simplified three-dimensional arterial models. The blood is considered as an incompressible Newtonian fluid obeying the Navier-Stokes equations of fluid flow. Therefore, these equations are used as a mathematical model to simulate the blood flow. Since these equations are difficult to solve analytically, a computational approach is utilized. To use this approach a suitable treatment of the complex arterial geometry is required. A proper numerical technique is also needed to solve the blood flow equations. A curvilinear coordinate system is used to solve the problem of geometry where an algebraic grid generation technique is used to generate the arterial geometry. The Navier-Stokes equations are written in the new coordinates and a computer program is developed utilizing the space marching method to integrate these equations for steady blood flow. The program is used to solve many problems that are of interest to hemodynamic studies. Results for flow with separated region (89% stenosis) and flow with secondary velocities (curved aneurysm) are presented and discussed. These results show the ability of the numerical methods to calculate the velocity fields and wall shear stress for three-dimensional arterial configurations.<>
{"title":"Numerical simulation of blood flow through arteries","authors":"A. Mazher, J. Ekaterinaris","doi":"10.1109/NEBC.1988.19404","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19404","url":null,"abstract":"Flow patterns are investigated in simplified three-dimensional arterial models. The blood is considered as an incompressible Newtonian fluid obeying the Navier-Stokes equations of fluid flow. Therefore, these equations are used as a mathematical model to simulate the blood flow. Since these equations are difficult to solve analytically, a computational approach is utilized. To use this approach a suitable treatment of the complex arterial geometry is required. A proper numerical technique is also needed to solve the blood flow equations. A curvilinear coordinate system is used to solve the problem of geometry where an algebraic grid generation technique is used to generate the arterial geometry. The Navier-Stokes equations are written in the new coordinates and a computer program is developed utilizing the space marching method to integrate these equations for steady blood flow. The program is used to solve many problems that are of interest to hemodynamic studies. Results for flow with separated region (89% stenosis) and flow with secondary velocities (curved aneurysm) are presented and discussed. These results show the ability of the numerical methods to calculate the velocity fields and wall shear stress for three-dimensional arterial configurations.<<ETX>>","PeriodicalId":165980,"journal":{"name":"Proceedings of the 1988 Fourteenth Annual Northeast Bioengineering Conference","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128777646","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}
The cardiac electrophysiological phenomena of reentrant excitation has been postulated as a possible mechanism for ventricular arrhythmias. Reentrant activation has been shown with the surviving epicardial layer as the electrophysiological substrate in a four-day canine post left anterior descending artery occlusion model. The thin surviving epicardial layer was simulated by a two-dimensional finite cable model with the active membrane properties modeled by modified Beeler-Reuter kinetics. The model surface consists of the periphery-reflecting normal membrane properties with progressively depressed membrane properties and decreased cellular coupling at the center of the surface. The functional significance of the simulation study of cell-cell electrical interaction during reentrant excitation is to provide a basis for understanding the spatial gradations of conduction velocity observed as regions of slow conduction leading to functional conduction block in the reentrant circuit.<>
{"title":"Simulation of cell to cell interaction during reentrant activation","authors":"V. Kowtha, J.K. Li","doi":"10.1109/NEBC.1988.19359","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19359","url":null,"abstract":"The cardiac electrophysiological phenomena of reentrant excitation has been postulated as a possible mechanism for ventricular arrhythmias. Reentrant activation has been shown with the surviving epicardial layer as the electrophysiological substrate in a four-day canine post left anterior descending artery occlusion model. The thin surviving epicardial layer was simulated by a two-dimensional finite cable model with the active membrane properties modeled by modified Beeler-Reuter kinetics. The model surface consists of the periphery-reflecting normal membrane properties with progressively depressed membrane properties and decreased cellular coupling at the center of the surface. The functional significance of the simulation study of cell-cell electrical interaction during reentrant excitation is to provide a basis for understanding the spatial gradations of conduction velocity observed as regions of slow conduction leading to functional conduction block in the reentrant circuit.<<ETX>>","PeriodicalId":165980,"journal":{"name":"Proceedings of the 1988 Fourteenth Annual Northeast Bioengineering Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129249228","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. Erickson, B. Beynnon, C. Werthiemer, B. Fleming, M. Pope, R. Johnson, J. Howe, C. Nichols
To diagnose an anterior cruciate ligament (ACL) injury, clinicians perform a Lachman test at 30 degrees of flexion or a Drawer test at 90 degrees of flexion to record how far the tibia displaces anteriorly with respect to the femur. A study was undertaken to characterize the normal strain pattern of the ACL in vivo during the Lachman and Drawer tests, and to determine if there is a significant difference between the strain patterns at clinically applied load levels. Five patients were studied. After routine arthroscopic surgery a Hall-effect displacement transducer was attached arthroscopically to the ACL to measure strain. Loads were applied by a hand-held load cell in a transverse plane directed through the midtibial tuberosity at flexion angles of 90 degrees and 30 degrees . The difference in percentage strain between the Lachman and Drawer tests was highly significant at p<0.01 level. These results clearly show that the Lachman test produces a greater elongation or strain in the ACL in comparison to the Drawer test at loads to 35 lb. From these data the authors characterize the normal ACL strain pattern.<>
{"title":"An in-vivo study of ACL strain in the normal knee during Lachman and Drawer tests","authors":"A. Erickson, B. Beynnon, C. Werthiemer, B. Fleming, M. Pope, R. Johnson, J. Howe, C. Nichols","doi":"10.1109/NEBC.1988.19332","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19332","url":null,"abstract":"To diagnose an anterior cruciate ligament (ACL) injury, clinicians perform a Lachman test at 30 degrees of flexion or a Drawer test at 90 degrees of flexion to record how far the tibia displaces anteriorly with respect to the femur. A study was undertaken to characterize the normal strain pattern of the ACL in vivo during the Lachman and Drawer tests, and to determine if there is a significant difference between the strain patterns at clinically applied load levels. Five patients were studied. After routine arthroscopic surgery a Hall-effect displacement transducer was attached arthroscopically to the ACL to measure strain. Loads were applied by a hand-held load cell in a transverse plane directed through the midtibial tuberosity at flexion angles of 90 degrees and 30 degrees . The difference in percentage strain between the Lachman and Drawer tests was highly significant at p<0.01 level. These results clearly show that the Lachman test produces a greater elongation or strain in the ACL in comparison to the Drawer test at loads to 35 lb. From these data the authors characterize the normal ACL strain pattern.<<ETX>>","PeriodicalId":165980,"journal":{"name":"Proceedings of the 1988 Fourteenth Annual Northeast Bioengineering Conference","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133748164","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}
It is shown that over a wide flow range, phasic changes in renal volume and the maximum rate of volume change may be reasonably predicted from changes in renal conductance using a model which assumes homogeneous geometric changes. However, the relationship deteriorates at high pump rates, stroke volumes, and therefore mean flow values. It is suggested that the expansion of the arteriolar bed occurring at the higher flow rates and stroke volumes causes a decrease in arteriolar compliance, which in turn causes a greater portion of the volume pulsation to be transmitted to the venous system, where the geometric assumptions may no longer be valid. The independent effect of rate is more difficult to explain. It may be due to a frequency resonance effect in which, at rates greater than the resonant frequency, the vascular bed remains at a greater state of expansion, again reducing arteriolar compliance and transmitting a greater portion of the volume pulsation to the venous system.<>
{"title":"Renal admittance plethysmography","authors":"L. Marks, D. Anaise, M. Yland","doi":"10.1109/NEBC.1988.19362","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19362","url":null,"abstract":"It is shown that over a wide flow range, phasic changes in renal volume and the maximum rate of volume change may be reasonably predicted from changes in renal conductance using a model which assumes homogeneous geometric changes. However, the relationship deteriorates at high pump rates, stroke volumes, and therefore mean flow values. It is suggested that the expansion of the arteriolar bed occurring at the higher flow rates and stroke volumes causes a decrease in arteriolar compliance, which in turn causes a greater portion of the volume pulsation to be transmitted to the venous system, where the geometric assumptions may no longer be valid. The independent effect of rate is more difficult to explain. It may be due to a frequency resonance effect in which, at rates greater than the resonant frequency, the vascular bed remains at a greater state of expansion, again reducing arteriolar compliance and transmitting a greater portion of the volume pulsation to the venous system.<<ETX>>","PeriodicalId":165980,"journal":{"name":"Proceedings of the 1988 Fourteenth Annual Northeast Bioengineering Conference","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130645901","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}
High-frequency current distribution was investigated while performing a simulated electrosurgical procedure (transurethral resection/TUR) in a canine model utilizing a function generator, spectrum analyzer, and current probes to measure current. Contour plots from recordings on integument muscle, nerve, vein, and artery tissue at sequential axial sites revealed current totals of 45% in artery, 24% in vein, 13% both in skin and muscle, and 5% in nerve. The investigations reveal that, during endoscopic (TUR) and other electrosurgical procedures, anatomic structures such as great vessels may act as preferential high-frequency current conduits and could potentially facilitate serious sequelae, such as obturator nerve-muscle spasm, electrical burns, or even cardiac arrythmias (at higher power levels).<>
{"title":"High frequency current distribution in axial body structures during electrosurgery","authors":"S. Selikowitz, J. Lacourse, G. Gerhard","doi":"10.1109/NEBC.1988.19360","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19360","url":null,"abstract":"High-frequency current distribution was investigated while performing a simulated electrosurgical procedure (transurethral resection/TUR) in a canine model utilizing a function generator, spectrum analyzer, and current probes to measure current. Contour plots from recordings on integument muscle, nerve, vein, and artery tissue at sequential axial sites revealed current totals of 45% in artery, 24% in vein, 13% both in skin and muscle, and 5% in nerve. The investigations reveal that, during endoscopic (TUR) and other electrosurgical procedures, anatomic structures such as great vessels may act as preferential high-frequency current conduits and could potentially facilitate serious sequelae, such as obturator nerve-muscle spasm, electrical burns, or even cardiac arrythmias (at higher power levels).<<ETX>>","PeriodicalId":165980,"journal":{"name":"Proceedings of the 1988 Fourteenth Annual Northeast Bioengineering Conference","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131787543","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 computer simulation of the Penn State rollerscrew electric ventricular assist device (EVAD) and the mock circulatory system has been developed for the purpose of control system design. The system model and simulation were verified for accuracy with a mock circulatory system using an EVAD. An observer based on a Luenberger observer was used to predict unmeasurable system pressures necessary for pump output control. From the simulation, accurate aortic pressure values were obtained using the observer during systole at a beat rate of 60 beats/min. The gains used in the observer were judiciously chosen, but a method for optimizing the feedback gains was developed. This method of selecting the observer gains which minimizes the error between the observer and the system is by pole placement rather than by statistical techniques.<>
{"title":"Aortic pressure estimation for the Penn State electric ventricular assist device","authors":"J. Koontz, U. Tsach, D. Geselowitz","doi":"10.1109/NEBC.1988.19375","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19375","url":null,"abstract":"A computer simulation of the Penn State rollerscrew electric ventricular assist device (EVAD) and the mock circulatory system has been developed for the purpose of control system design. The system model and simulation were verified for accuracy with a mock circulatory system using an EVAD. An observer based on a Luenberger observer was used to predict unmeasurable system pressures necessary for pump output control. From the simulation, accurate aortic pressure values were obtained using the observer during systole at a beat rate of 60 beats/min. The gains used in the observer were judiciously chosen, but a method for optimizing the feedback gains was developed. This method of selecting the observer gains which minimizes the error between the observer and the system is by pole placement rather than by statistical techniques.<<ETX>>","PeriodicalId":165980,"journal":{"name":"Proceedings of the 1988 Fourteenth Annual Northeast Bioengineering Conference","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117018980","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}
Experiments were conducted in which postures of the elbow and forearm were quasistatically maintained through deliberate cocontraction of the biceps and triceps, the principal flexor and extensor muscles acting about the elbow. The object of these experiments was to record the levels of muscular activation for the biceps and triceps as various postures of the elbow and forearm were maintained for a full range of cocontraction. Trials were conducted over a range of elbow angle from near fully flexed to near fully extended. Preliminary results from these experiments are presented. These show that for forearm postures away from the midrange of the elbow, cocontraction leads to antagonist muscle activation levels that, are significantly larger than the corresponding level of agonist activation i.e., the muscle supporting the limb against gravity is not working as hard as its antagonist counterpart. An explanation of these counterintuitive results is presented, based on assumed length-dependence of the muscle efficiency relating neural input to muscle force.<>
{"title":"Maintenance of elbow equilibrium through co-contraction","authors":"W. Murray","doi":"10.1109/NEBC.1988.19335","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19335","url":null,"abstract":"Experiments were conducted in which postures of the elbow and forearm were quasistatically maintained through deliberate cocontraction of the biceps and triceps, the principal flexor and extensor muscles acting about the elbow. The object of these experiments was to record the levels of muscular activation for the biceps and triceps as various postures of the elbow and forearm were maintained for a full range of cocontraction. Trials were conducted over a range of elbow angle from near fully flexed to near fully extended. Preliminary results from these experiments are presented. These show that for forearm postures away from the midrange of the elbow, cocontraction leads to antagonist muscle activation levels that, are significantly larger than the corresponding level of agonist activation i.e., the muscle supporting the limb against gravity is not working as hard as its antagonist counterpart. An explanation of these counterintuitive results is presented, based on assumed length-dependence of the muscle efficiency relating neural input to muscle force.<<ETX>>","PeriodicalId":165980,"journal":{"name":"Proceedings of the 1988 Fourteenth Annual Northeast Bioengineering Conference","volume":"93 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117302917","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}
The problem of unsupervised segmentation of coronary angiograms is investigated. An algorithm which uses an iterative line search procedure to adapt the segmentation thresholds is proposed. This algorithm is parallel in nature, and could be implemented on a disturbed computer architecture. Based on the angiogram's histogram, two thresholds are obtained which classify the pixels into three types: artery, background, and unclassified, The threshold adaptation is an iterative process. A heuristic line search is conducted throughout the neighborhoods of the unclassified pixels. The results of the search are used to adapt the thresholds. The process is continued until all pixels are classified as either artery or background. The algorithm was implemented on an IBM PC/AT-based imaging system and tested with coronary arteriogram images. Preliminary results demonstrated the algorithm's usefulness in enhancing the arterial structure, even under low signal-to-noise ratios. Furthermore, the segmentation was achieved within a few iterations.<>
{"title":"Adaptive segmentation of coronary angiograms","authors":"D. Kottke, Ying Sun","doi":"10.1109/NEBC.1988.19408","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19408","url":null,"abstract":"The problem of unsupervised segmentation of coronary angiograms is investigated. An algorithm which uses an iterative line search procedure to adapt the segmentation thresholds is proposed. This algorithm is parallel in nature, and could be implemented on a disturbed computer architecture. Based on the angiogram's histogram, two thresholds are obtained which classify the pixels into three types: artery, background, and unclassified, The threshold adaptation is an iterative process. A heuristic line search is conducted throughout the neighborhoods of the unclassified pixels. The results of the search are used to adapt the thresholds. The process is continued until all pixels are classified as either artery or background. The algorithm was implemented on an IBM PC/AT-based imaging system and tested with coronary arteriogram images. Preliminary results demonstrated the algorithm's usefulness in enhancing the arterial structure, even under low signal-to-noise ratios. Furthermore, the segmentation was achieved within a few iterations.<<ETX>>","PeriodicalId":165980,"journal":{"name":"Proceedings of the 1988 Fourteenth Annual Northeast Bioengineering Conference","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131607869","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}
Several design variations were tested in Guy muscle equivalent phantom. A phantom experiment was set up to measure power deposition at 221 or 425 points in the plane of a single antenna or pair of antennas. Antennas were constructed and tested with different helical designs. Antennas with helical-tip vs. helical-junction connections were compared. Oppositely wound pairs were tested and compared with identically wound helixes. The effect of a large junction gap was investigated. A dual-density winding antenna was tested to improve power deposition. All antennas were tested singly and in pairs to gauge interaction. The control antennas were Dartmouth dipoles used in clinical hyperthermia. Finally, actual human temperature data are shown and compared to power deposition patterns. Clinical implications for the antenna array data are discussed.<>
{"title":"Variations in the design of a helical tip microwave antenna for hyperthermia","authors":"T. Ryan, J. Strohbehn","doi":"10.1109/NEBC.1988.19364","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19364","url":null,"abstract":"Several design variations were tested in Guy muscle equivalent phantom. A phantom experiment was set up to measure power deposition at 221 or 425 points in the plane of a single antenna or pair of antennas. Antennas were constructed and tested with different helical designs. Antennas with helical-tip vs. helical-junction connections were compared. Oppositely wound pairs were tested and compared with identically wound helixes. The effect of a large junction gap was investigated. A dual-density winding antenna was tested to improve power deposition. All antennas were tested singly and in pairs to gauge interaction. The control antennas were Dartmouth dipoles used in clinical hyperthermia. Finally, actual human temperature data are shown and compared to power deposition patterns. Clinical implications for the antenna array data are discussed.<<ETX>>","PeriodicalId":165980,"journal":{"name":"Proceedings of the 1988 Fourteenth Annual Northeast Bioengineering Conference","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131841575","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}
Recent literature suggests a correlation between the acoustic signals produced by working muscles and the health, effort, and fatigue levels of the muscles. Practical experience gained in setting up a computer-based system to acquire and analyze the myoacoustic signal is discussed. Topics discussed include: obtaining the low frequency (5-50-Hz) signals; signal-to-noise ratio; protocol; and artifact considerations. Preliminary results indicate that large artifact signals are inherent in the frequency range of interest. A simple signal and transducer model is proposed to explain these observations.<>
{"title":"Practical experience obtaining acoustic myographic signals","authors":"C. Tupper, G. Gerhard","doi":"10.1109/NEBC.1988.19370","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19370","url":null,"abstract":"Recent literature suggests a correlation between the acoustic signals produced by working muscles and the health, effort, and fatigue levels of the muscles. Practical experience gained in setting up a computer-based system to acquire and analyze the myoacoustic signal is discussed. Topics discussed include: obtaining the low frequency (5-50-Hz) signals; signal-to-noise ratio; protocol; and artifact considerations. Preliminary results indicate that large artifact signals are inherent in the frequency range of interest. A simple signal and transducer model is proposed to explain these observations.<<ETX>>","PeriodicalId":165980,"journal":{"name":"Proceedings of the 1988 Fourteenth Annual Northeast Bioengineering Conference","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134496607","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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