The coronary sinus occlusion pressure exhibits complicated frequency characteristics which can be modeled by either a nonlinear system approach or a high-order LTI (linear time-invariant) system approach. The LTI system presents a superior modeling methodology, due to the applicability of powerful analytical tools such as Fourier analysis. Using linear system identification techniques, a fifth-order LTI system was obtained to characterize coronary sinus occlusion pressure waveforms. Linear systems of lower order were found to have insufficient degree of freedom to model the hemodynamics of the coronary sinus occlusion. The resulting model from the systematic identification process was stable within a broad range of variations of heart rate and time constant of the coronary sinus occlusion pressure. This model provides a mathematical basis to study distributive properties in the coronary venous circulation and to optimize various treatment procedures of myocardium diseases via the coronary sinus.<>
{"title":"Hemodynamics of coronary sinus occlusion: a linear model","authors":"A. Mo, Y. Sun","doi":"10.1109/NEBC.1988.19406","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19406","url":null,"abstract":"The coronary sinus occlusion pressure exhibits complicated frequency characteristics which can be modeled by either a nonlinear system approach or a high-order LTI (linear time-invariant) system approach. The LTI system presents a superior modeling methodology, due to the applicability of powerful analytical tools such as Fourier analysis. Using linear system identification techniques, a fifth-order LTI system was obtained to characterize coronary sinus occlusion pressure waveforms. Linear systems of lower order were found to have insufficient degree of freedom to model the hemodynamics of the coronary sinus occlusion. The resulting model from the systematic identification process was stable within a broad range of variations of heart rate and time constant of the coronary sinus occlusion pressure. This model provides a mathematical basis to study distributive properties in the coronary venous circulation and to optimize various treatment procedures of myocardium diseases via the coronary sinus.<<ETX>>","PeriodicalId":165980,"journal":{"name":"Proceedings of the 1988 Fourteenth Annual Northeast Bioengineering Conference","volume":"19 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":"127868672","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}
An anatomically based mathematical model of the passive constraints, including both surface contacts and ligaments and based on screw theory, is presented as a method of assessing the instantaneous total freedom of the knee. Screw theory address the full three-dimensional kinematics and allows consideration of motions that release or violate constraints. Models for the ligamentous and articular surface constraints are proposed and procedures for formulating and solving model equations are presented.<>
{"title":"Passive constraint analysis of the knee","authors":"M. Murphy, R. Mann","doi":"10.1109/NEBC.1988.19337","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19337","url":null,"abstract":"An anatomically based mathematical model of the passive constraints, including both surface contacts and ligaments and based on screw theory, is presented as a method of assessing the instantaneous total freedom of the knee. Screw theory address the full three-dimensional kinematics and allows consideration of motions that release or violate constraints. Models for the ligamentous and articular surface constraints are proposed and procedures for formulating and solving model equations are presented.<<ETX>>","PeriodicalId":165980,"journal":{"name":"Proceedings of the 1988 Fourteenth Annual Northeast Bioengineering Conference","volume":"281 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":"115553240","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}
An experimental method utilizing a high-speed computerized image analysis system to measure the cross-sectional area of ligament tissue was developed. The method consists of flash-freezing ligament tissue in liquid nitrogen and then sectioning the tissue at discrete locations along its length. A nondestructive casting technique was also developed to determine the cross-sectional area of ligament specimens prior to sectioning. Images of individual cross-sections for both ligament and cast sections were acquired using a high-resolution video-camera system. A comparison study was performed for an average area value of ligament cross sections and an average area value for cast cross sections. The variations between these are within 8.3%. A section-by-section comparison of ligament versus casting was also performed. In most cases, the variations between ligament section and cast section was less than 10%. The casting technique utilizing the image analysis system in an accurate, nondestructive way to determine the cross-sectional area of ligament tissue. It does not assume a shape for the area and can detect concavities on the surface of the tissue.<>
{"title":"Measurements of ligament tissue cross-sectional area","authors":"D.J. Lanzendorf, M. Murphy, R. Mann","doi":"10.1109/NEBC.1988.19333","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19333","url":null,"abstract":"An experimental method utilizing a high-speed computerized image analysis system to measure the cross-sectional area of ligament tissue was developed. The method consists of flash-freezing ligament tissue in liquid nitrogen and then sectioning the tissue at discrete locations along its length. A nondestructive casting technique was also developed to determine the cross-sectional area of ligament specimens prior to sectioning. Images of individual cross-sections for both ligament and cast sections were acquired using a high-resolution video-camera system. A comparison study was performed for an average area value of ligament cross sections and an average area value for cast cross sections. The variations between these are within 8.3%. A section-by-section comparison of ligament versus casting was also performed. In most cases, the variations between ligament section and cast section was less than 10%. The casting technique utilizing the image analysis system in an accurate, nondestructive way to determine the cross-sectional area of ligament tissue. It does not assume a shape for the area and can detect concavities on the surface of the tissue.<<ETX>>","PeriodicalId":165980,"journal":{"name":"Proceedings of the 1988 Fourteenth Annual Northeast Bioengineering Conference","volume":"38 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":"115641618","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 linear array of three high sensitivity piezoelectric crystals are spaced 0.75 cm apart and bonded to a plastic block. The crystals are used in the thickness compression mode to measure the pressure pulse. The signal from each crystal is amplified and processed for noise reduction. The array is aligned perpendicular to the artery, and information from the off-axis sensors is averaged and subtracted from the on-axis signal. In addition, the sensors are aligned on-axis for determination of blood velocity from the phase difference between sensors. Experimental results indicate that motion artifact is mostly common-mode and that the contact stress on the surface of the skin is therefore uniform. Preliminary cancellation techniques provided are simple yet effective in restoring disturbed pulse recordings.<>
{"title":"Array sensor for arterial pulse recording-reduction of motion artifact","authors":"E. Ciaccio, G. Drzewiecki","doi":"10.1109/NEBC.1988.19345","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19345","url":null,"abstract":"A linear array of three high sensitivity piezoelectric crystals are spaced 0.75 cm apart and bonded to a plastic block. The crystals are used in the thickness compression mode to measure the pressure pulse. The signal from each crystal is amplified and processed for noise reduction. The array is aligned perpendicular to the artery, and information from the off-axis sensors is averaged and subtracted from the on-axis signal. In addition, the sensors are aligned on-axis for determination of blood velocity from the phase difference between sensors. Experimental results indicate that motion artifact is mostly common-mode and that the contact stress on the surface of the skin is therefore uniform. Preliminary cancellation techniques provided are simple yet effective in restoring disturbed pulse recordings.<<ETX>>","PeriodicalId":165980,"journal":{"name":"Proceedings of the 1988 Fourteenth Annual Northeast Bioengineering Conference","volume":"19 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":"114197210","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 effect of sodium nitroprusside (NP) infusion on systemic arterial compliance in hypertensive subjects was assessed using pulse-contour analysis (PCA). Seven male patients aged 41 to 71 years (mean age 59 years) were studied after 30 minutes rest in the supine position and during continuous NP infusion. Proximal arterial compliance, C1, and distal arterial compliance, C2, were determined by analyzing the diastolic portion of a brachial artery pressure pulse and cardiac output (CO). During NP infusion, mean arterial pressure (MAP) decreased by 19% (p<0.02), heart rate (HR) increased by 11% (p< 0.02), and CO decreased by 12%. Systemic vascular resistance (SVR) tended to decrease (6%), but this response was somewhat variable. Both C1 and C2 exhibited a significant increase, with C1 rising by 17% (p<0.10) and C2 rising by 326% (p<0.02). These data indicate that NP may be exerting its pressure-lowering effects both by dilating arterial vessels and by making them more compliant. Furthermore, it appears that both C1 and C2 are more sensitive indicators of changes in vascular functional state than SVR.<>
{"title":"Vascular compliance after nitroprusside in hypertension","authors":"W. Feske, S. Finkelstein, G. Francis, J. Cohn","doi":"10.1109/NEBC.1988.19405","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19405","url":null,"abstract":"The effect of sodium nitroprusside (NP) infusion on systemic arterial compliance in hypertensive subjects was assessed using pulse-contour analysis (PCA). Seven male patients aged 41 to 71 years (mean age 59 years) were studied after 30 minutes rest in the supine position and during continuous NP infusion. Proximal arterial compliance, C1, and distal arterial compliance, C2, were determined by analyzing the diastolic portion of a brachial artery pressure pulse and cardiac output (CO). During NP infusion, mean arterial pressure (MAP) decreased by 19% (p<0.02), heart rate (HR) increased by 11% (p< 0.02), and CO decreased by 12%. Systemic vascular resistance (SVR) tended to decrease (6%), but this response was somewhat variable. Both C1 and C2 exhibited a significant increase, with C1 rising by 17% (p<0.10) and C2 rising by 326% (p<0.02). These data indicate that NP may be exerting its pressure-lowering effects both by dilating arterial vessels and by making them more compliant. Furthermore, it appears that both C1 and C2 are more sensitive indicators of changes in vascular functional state than SVR.<<ETX>>","PeriodicalId":165980,"journal":{"name":"Proceedings of the 1988 Fourteenth Annual Northeast Bioengineering Conference","volume":"23 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":"132130390","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}
Bispectral analyses were utilized to study the rat electroencephalogram (EEG) to extract information regarding phase coupling. The results indicate that the EEG recorded from the hippocampus exhibits a strong phase coupling between frequencies in the theta band (6-8 Hz) primarily during REM sleep, while the cortical EEG exhibits a weak coupling between flow frequencies in the delta band (0-3 Hz) during quiet-waking. The degree of phase coupling was further quantified using the biocoherence function. This study provides data not available from traditional power-spectral analysis.<>
{"title":"Detecting phase coupling of sleep EEG via bispectra","authors":"T. Ning, J. Bronzino","doi":"10.1109/NEBC.1988.19383","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19383","url":null,"abstract":"Bispectral analyses were utilized to study the rat electroencephalogram (EEG) to extract information regarding phase coupling. The results indicate that the EEG recorded from the hippocampus exhibits a strong phase coupling between frequencies in the theta band (6-8 Hz) primarily during REM sleep, while the cortical EEG exhibits a weak coupling between flow frequencies in the delta band (0-3 Hz) during quiet-waking. The degree of phase coupling was further quantified using the biocoherence function. This study provides data not available from traditional power-spectral analysis.<<ETX>>","PeriodicalId":165980,"journal":{"name":"Proceedings of the 1988 Fourteenth Annual Northeast Bioengineering Conference","volume":"19 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":"126519443","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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