Mean arterial pressure (MAP) and average blood pressure (ABP) are compared. MAP is normally computed as some weighted mean of systolic and diastolic pressures. Average blood pressure is defined here as the area under the pressure pulse contour divided by the duration of the heart cycle. Using equations for the pressure pulse contour found in the literature, a closed-form solution for the ABP was developed and compared to the expression for MAP. It is shown that, in general, MAP and ABP are different; that MAP can underestimate or overestimate ABP depending upon how the systolic and diastolic pressures are weighted. In the case of a normal adult with a pressure of 120/80 mm of mercury, the difference between MAP and ABP is on the order of 6 to 8%. It is conjectured that the error would be larger in the hypertensive patients.<>
{"title":"Mean arterial pressure and average blood pressure","authors":"J. Libii","doi":"10.1109/NEBC.1988.19386","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19386","url":null,"abstract":"Mean arterial pressure (MAP) and average blood pressure (ABP) are compared. MAP is normally computed as some weighted mean of systolic and diastolic pressures. Average blood pressure is defined here as the area under the pressure pulse contour divided by the duration of the heart cycle. Using equations for the pressure pulse contour found in the literature, a closed-form solution for the ABP was developed and compared to the expression for MAP. It is shown that, in general, MAP and ABP are different; that MAP can underestimate or overestimate ABP depending upon how the systolic and diastolic pressures are weighted. In the case of a normal adult with a pressure of 120/80 mm of mercury, the difference between MAP and ABP is on the order of 6 to 8%. It is conjectured that the error would be larger in the hypertensive patients.<<ETX>>","PeriodicalId":165980,"journal":{"name":"Proceedings of the 1988 Fourteenth Annual Northeast Bioengineering Conference","volume":"4 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":"131276422","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 parametric model for implant design has been developed and incorporated into an expert system for prosthesis design and manufacturing. The expert system acquires data concerning the physical characteristics of a patient, (e.g., age, height, weight, and anatomical details of the femoral geometry). The system conceptualizes a space-filling custom design based upon the available data and calculations. The system considers existing off-the-shelf designs and the custom design as parallel alternatives and applies geometric criteria to eliminate designs that are incompatible with the patient's data. The remaining designs are used to generate finite-element models, and are evaluated for bone/prosthesis stress levels. The system 'reasons' about the final designs in an iterative fashion.<>
{"title":"Custom implant analysis system","authors":"R. L. Dooley, A. Dingankar, G. Heimke, E. Berg","doi":"10.1109/NEBC.1988.19338","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19338","url":null,"abstract":"A parametric model for implant design has been developed and incorporated into an expert system for prosthesis design and manufacturing. The expert system acquires data concerning the physical characteristics of a patient, (e.g., age, height, weight, and anatomical details of the femoral geometry). The system conceptualizes a space-filling custom design based upon the available data and calculations. The system considers existing off-the-shelf designs and the custom design as parallel alternatives and applies geometric criteria to eliminate designs that are incompatible with the patient's data. The remaining designs are used to generate finite-element models, and are evaluated for bone/prosthesis stress levels. The system 'reasons' about the final designs in an iterative fashion.<<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":"122574096","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 finite-element model is used to determine the internal wall stresses in a rat aorta compressed with a U-shaped clip. These results are correlated with the location of various cell shapes found in vivo. Previous studies with this stenosis found polygonal cells and increased lipid deposition in small regions adjacent to each edge of the clip. The finite-element calculations suggest that the internal wall longitudinal shear stress changes sign rapidly over these small sections. By assuming that the permeability of the polygonal cells is much higher than in normal endothelial cells, the rate of lipoprotein uptake through the endothelium is calculated. As expected, the blood itself provides little resistance to the lipid uptake and significant transfer takes place only in the regions with the elevated permeability.<>
{"title":"Modeling lipid transport through the transverse clip stenosis","authors":"B. MacWilliams, B. Savilonis, A. Hoffman","doi":"10.1109/NEBC.1988.19385","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19385","url":null,"abstract":"A finite-element model is used to determine the internal wall stresses in a rat aorta compressed with a U-shaped clip. These results are correlated with the location of various cell shapes found in vivo. Previous studies with this stenosis found polygonal cells and increased lipid deposition in small regions adjacent to each edge of the clip. The finite-element calculations suggest that the internal wall longitudinal shear stress changes sign rapidly over these small sections. By assuming that the permeability of the polygonal cells is much higher than in normal endothelial cells, the rate of lipoprotein uptake through the endothelium is calculated. As expected, the blood itself provides little resistance to the lipid uptake and significant transfer takes place only in the regions with the elevated permeability.<<ETX>>","PeriodicalId":165980,"journal":{"name":"Proceedings of the 1988 Fourteenth Annual Northeast Bioengineering Conference","volume":"57 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":"125021532","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 effectiveness of tactile feedback is studied in conveying screen information to the user is studied. An existing mouse design was modified to include a piezoelectric transducer which presents vibrations to the tip of the index finger when the cursor arrives at a screen target. To test the hypothesis that tactile feedback would effect a more efficient use of the mouse, a preliminary study was undertaken using a computer program which sequentially places targets randomly about the screen, with targets being assigned either tactile feedback or no feedback. One group in the study operated under conditions of normal visibility while a second group operated under conditions of reduced visibility. The results, with 2470 trials and 19 subjects indicate that, under conditions of reduced visibility, tactile feedback decreases response time by 0.10 seconds. It is concluded that despite this modest time gain, tactile feedback promises to be a useful modality for conveying screen information, especially in cases of visual impairment.<>
{"title":"Tactile feedback in a computer mouse","authors":"J. Terry, H. Hsiao","doi":"10.1109/NEBC.1988.19369","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19369","url":null,"abstract":"The effectiveness of tactile feedback is studied in conveying screen information to the user is studied. An existing mouse design was modified to include a piezoelectric transducer which presents vibrations to the tip of the index finger when the cursor arrives at a screen target. To test the hypothesis that tactile feedback would effect a more efficient use of the mouse, a preliminary study was undertaken using a computer program which sequentially places targets randomly about the screen, with targets being assigned either tactile feedback or no feedback. One group in the study operated under conditions of normal visibility while a second group operated under conditions of reduced visibility. The results, with 2470 trials and 19 subjects indicate that, under conditions of reduced visibility, tactile feedback decreases response time by 0.10 seconds. It is concluded that despite this modest time gain, tactile feedback promises to be a useful modality for conveying screen information, especially in cases of visual impairment.<<ETX>>","PeriodicalId":165980,"journal":{"name":"Proceedings of the 1988 Fourteenth Annual Northeast Bioengineering Conference","volume":"8 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":"117099424","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}
Electrical stimulation via the esophageal pathway has been demonstrated to be a relatively noninvasive and recommendable approach to cardiac pacing to the termination of arrhythmias. Hemodynamics consequences of this mode of pacing on arterial system function have not been reported. The authors anaesthetized dogs using bipolar catheter electrodes; their results show that transesophageal cardiac pacing alters arterial pulse transmission characteristics only to a limited extent.<>
{"title":"Esophageal cardiac pacing effects on arterial pulsations","authors":"P.S. Geipel, C. Jensen, J.K. Li","doi":"10.1109/NEBC.1988.19390","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19390","url":null,"abstract":"Electrical stimulation via the esophageal pathway has been demonstrated to be a relatively noninvasive and recommendable approach to cardiac pacing to the termination of arrhythmias. Hemodynamics consequences of this mode of pacing on arterial system function have not been reported. The authors anaesthetized dogs using bipolar catheter electrodes; their results show that transesophageal cardiac pacing alters arterial pulse transmission characteristics only to a limited extent.<<ETX>>","PeriodicalId":165980,"journal":{"name":"Proceedings of the 1988 Fourteenth Annual Northeast Bioengineering Conference","volume":"5 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":"121766453","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}
Experimental results of the application of a hidden-Markov-model-based isolated-word recognition procedure to nonverbal speech are presented. Effects of different model structures on the accuracy of recognition are discussed.<>
{"title":"Applying hidden Markov models to recognition of nonverbal speech","authors":"D. Hsu, J. Deller","doi":"10.1109/NEBC.1988.19392","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19392","url":null,"abstract":"Experimental results of the application of a hidden-Markov-model-based isolated-word recognition procedure to nonverbal speech are presented. Effects of different model structures on the accuracy of recognition are discussed.<<ETX>>","PeriodicalId":165980,"journal":{"name":"Proceedings of the 1988 Fourteenth Annual Northeast Bioengineering Conference","volume":"62 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":"125888107","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 simple model representing the quasistatic behavior of skeleton muscle in which the force produced by the muscle is a bilinear function of the muscle length and the neural activation of the muscle is presented. Using two such muscles to represent the biceps and triceps, a biomechanical model of the elbow and forearm is developed. Predictions for the quasistatic maintenance of posture are given. The competence of this model is assessed on the basis of preliminary experimental data.<>
{"title":"Modelling elbow equilibrium in the presence of co-contraction","authors":"W. Murray","doi":"10.1109/NEBC.1988.19381","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19381","url":null,"abstract":"A simple model representing the quasistatic behavior of skeleton muscle in which the force produced by the muscle is a bilinear function of the muscle length and the neural activation of the muscle is presented. Using two such muscles to represent the biceps and triceps, a biomechanical model of the elbow and forearm is developed. Predictions for the quasistatic maintenance of posture are given. The competence of this model is assessed on the basis of preliminary experimental data.<<ETX>>","PeriodicalId":165980,"journal":{"name":"Proceedings of the 1988 Fourteenth Annual Northeast Bioengineering Conference","volume":"08 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":"130565862","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}
C. Stanley, M. Pathak, G. Nuñez, J. Sneckenberger, T. Whitmoyer
Frequency analysis of acoustic waves sent into, and reflected from, lung airways is being studied as a possible early indicator of lung disease. To help evaluate the acoustic impedance of the lung, a method has been developed to determine which parts of the surface of an excised lung are responding to the acoustic excitation via the trachea. Holographic interferometry, a very sensitive technique that can measure movements of a few mu m, is being used to detect the lung-surface movement. Lungs from normal guinea pigs are being analyzed. Acoustic waves at selected frequencies are sent into the trachea and a double-exposure holograph is made of the lung. Each exposure is approximately 4 ms in duration with a separation of 2 ms. The laser pulse is obtained by interrupting the beam from a 0.5-w argon ion laser. Fringe patterns produced are an indication of lung movement. Work is continuing to distinguish normal and diseased lungs using a combination of acoustic excitation and holographic interferometric techniques.<>
{"title":"Technique to apply holographic interferometry to excised animal lungs","authors":"C. Stanley, M. Pathak, G. Nuñez, J. Sneckenberger, T. Whitmoyer","doi":"10.1109/NEBC.1988.19349","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19349","url":null,"abstract":"Frequency analysis of acoustic waves sent into, and reflected from, lung airways is being studied as a possible early indicator of lung disease. To help evaluate the acoustic impedance of the lung, a method has been developed to determine which parts of the surface of an excised lung are responding to the acoustic excitation via the trachea. Holographic interferometry, a very sensitive technique that can measure movements of a few mu m, is being used to detect the lung-surface movement. Lungs from normal guinea pigs are being analyzed. Acoustic waves at selected frequencies are sent into the trachea and a double-exposure holograph is made of the lung. Each exposure is approximately 4 ms in duration with a separation of 2 ms. The laser pulse is obtained by interrupting the beam from a 0.5-w argon ion laser. Fringe patterns produced are an indication of lung movement. Work is continuing to distinguish normal and diseased lungs using a combination of acoustic excitation and holographic interferometric techniques.<<ETX>>","PeriodicalId":165980,"journal":{"name":"Proceedings of the 1988 Fourteenth Annual Northeast Bioengineering Conference","volume":"222 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":"131621076","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 pattern-recognition algorithm and the required instrumentation to apply it for in vivo human liver tissue differentiation are discussed. The algorithm has been tested successfully, with a confidence interval of 68.27%, on 25 subjects with no history of liver diseases and 15 subjects with different types of abnormalities. Differentiation between normal and abnormal liver tissue is accomplished by calculating the Euclidean distance between a reference vector and a pattern vector. The elements of the reference vector are the precalculated values of the average attenuation and backscattering coefficients of normal liver tissue at each frequency interval in the range from 1.5 to 4.5 MHz. Elements of the pattern vector are the average values of the two coefficients for the liver tissue under consideration at each frequency interval. This distance is a measure of the probability that the liver under consideration is normal. An empirical threshold is selected such that if the distance is less than the threshold, then the liver is declared normal otherwise it is abnormal. The instrumentation implemented is a high speed microprocessor-based data acquisition and analysis system. The system digitizes the backscattered ultrasound signal and stores the digitized data in a microcomputer where it is analyzed.<>
{"title":"In-vivo human liver tissue differentiation","authors":"N. Botros","doi":"10.1109/NEBC.1988.19346","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19346","url":null,"abstract":"A pattern-recognition algorithm and the required instrumentation to apply it for in vivo human liver tissue differentiation are discussed. The algorithm has been tested successfully, with a confidence interval of 68.27%, on 25 subjects with no history of liver diseases and 15 subjects with different types of abnormalities. Differentiation between normal and abnormal liver tissue is accomplished by calculating the Euclidean distance between a reference vector and a pattern vector. The elements of the reference vector are the precalculated values of the average attenuation and backscattering coefficients of normal liver tissue at each frequency interval in the range from 1.5 to 4.5 MHz. Elements of the pattern vector are the average values of the two coefficients for the liver tissue under consideration at each frequency interval. This distance is a measure of the probability that the liver under consideration is normal. An empirical threshold is selected such that if the distance is less than the threshold, then the liver is declared normal otherwise it is abnormal. The instrumentation implemented is a high speed microprocessor-based data acquisition and analysis system. The system digitizes the backscattered ultrasound signal and stores the digitized data in a microcomputer where it is analyzed.<<ETX>>","PeriodicalId":165980,"journal":{"name":"Proceedings of the 1988 Fourteenth Annual Northeast Bioengineering Conference","volume":"2 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":"116625335","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 advances in the theory of bioheat transfer suggest that perfused tissue might be modeled best by a thermally conductive solid with a perfusion-dependent conductivity. The blood perfusion is believed to enhance the conductivity anisotropically in the direction of thermally significant counter current blood vessels. Traditionally, heat transfer in tissue has been modeled as an isotropic heat sink. Due to the directional nature of recent theory, single point probes cannot adequately quantify the thermal characteristics of tissue. The theoretical analysis and hardware design of a multiple sensor probe that can be used to determine the coefficients of the thermal conductivity tensor are presented. The probe consists of an array of thermistors with the central thermistor acting as a heat source and the surrounding thermistors as temperature sensors. The system is computer-controlled and heating is done either in a pulse-decay mode or as a step input of power. Results of model calculations and of tests on a prototype are presented.<>
{"title":"A multi-sensor array to measure anisotropic thermal conductivity of tissue","authors":"E. Cheever, J. Baish, M.L. Wennemyr","doi":"10.1109/NEBC.1988.19329","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19329","url":null,"abstract":"Recent advances in the theory of bioheat transfer suggest that perfused tissue might be modeled best by a thermally conductive solid with a perfusion-dependent conductivity. The blood perfusion is believed to enhance the conductivity anisotropically in the direction of thermally significant counter current blood vessels. Traditionally, heat transfer in tissue has been modeled as an isotropic heat sink. Due to the directional nature of recent theory, single point probes cannot adequately quantify the thermal characteristics of tissue. The theoretical analysis and hardware design of a multiple sensor probe that can be used to determine the coefficients of the thermal conductivity tensor are presented. The probe consists of an array of thermistors with the central thermistor acting as a heat source and the surrounding thermistors as temperature sensors. The system is computer-controlled and heating is done either in a pulse-decay mode or as a step input of power. Results of model calculations and of tests on a prototype are presented.<<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":"123564307","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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