Hemodynamic control variables such as left atrial pressure, heart rate, and tension time index have been examined for in-series cardiac assistance using the intraaortic balloon pump. Automatic control algorithms have been constructed based on analog models of the assisted circulation. These are reviewed and a scheme for implantable automatic controlled cardiac assist devices are proposed.<>
{"title":"Control variables and algorithms for in series cardiac assistance","authors":"T. Cui, J.K. Li, W. Welkowitz, S. Petrucelli","doi":"10.1109/NEBC.1988.19328","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19328","url":null,"abstract":"Hemodynamic control variables such as left atrial pressure, heart rate, and tension time index have been examined for in-series cardiac assistance using the intraaortic balloon pump. Automatic control algorithms have been constructed based on analog models of the assisted circulation. These are reviewed and a scheme for implantable automatic controlled cardiac assist devices are proposed.<<ETX>>","PeriodicalId":165980,"journal":{"name":"Proceedings of the 1988 Fourteenth Annual Northeast Bioengineering Conference","volume":"3 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":"125501456","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 instrument which noninvasively and accurately measures the ocular pulse is described. To acquire this signal, a fiber Fizeau interferometer operating at a wavelength of 632 nm is used. A unique dithering and signal processing scheme allows standard FM demodulation techniques to recover the ocular pulse signal from the interference pattern. A detailed description of this data acquisition method is presented along with the results of test measurements made on a model eye.<>
{"title":"Interferometric measurement of the ocular pulse","authors":"D. Campagna, A. Drake","doi":"10.1109/NEBC.1988.19361","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19361","url":null,"abstract":"An instrument which noninvasively and accurately measures the ocular pulse is described. To acquire this signal, a fiber Fizeau interferometer operating at a wavelength of 632 nm is used. A unique dithering and signal processing scheme allows standard FM demodulation techniques to recover the ocular pulse signal from the interference pattern. A detailed description of this data acquisition method is presented along with the results of test measurements made on a model eye.<<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":"126866972","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}
Rheological properties of thoracic aorta in vitro have been studied by subjecting tissue samples to incremental loading and unloading using a specially developed biaxial loading apparatus. It was found that the rheological behaviour under loading is significantly different from that under unloading. Results indicate that below a threshold value of a nonlinear strain, the material does not display any time-dependent response. The observed behavior has been attributed to the microstructural makeup of the aortic wall.<>
{"title":"Rheological properties of large arteries","authors":"M. Sharma","doi":"10.1109/NEBC.1988.19377","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19377","url":null,"abstract":"Rheological properties of thoracic aorta in vitro have been studied by subjecting tissue samples to incremental loading and unloading using a specially developed biaxial loading apparatus. It was found that the rheological behaviour under loading is significantly different from that under unloading. Results indicate that below a threshold value of a nonlinear strain, the material does not display any time-dependent response. The observed behavior has been attributed to the microstructural makeup of the aortic wall.<<ETX>>","PeriodicalId":165980,"journal":{"name":"Proceedings of the 1988 Fourteenth Annual Northeast Bioengineering Conference","volume":"71 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":"115220390","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 multichannel autoregressive model and the periodogram approach are used to determine coherence and phase measures between the electrical activity in two distinct brain structures of the rat namely, the subfields CA1 and dentate gyrus in the hippocampal formation, during the vigilance states of quiet waking (QW), slow-wave sleep (SWS), and rapid-eye-movement (REM) sleep. Using both periodogram and multichannel autoregressive modeling techniques, high coherence and consistent phase differences were found to exist within the theta range of frequencies (4-11 Hz) only during REM sleep.<>
{"title":"Coherence analysis of EEG via multichannel AR modeling","authors":"M. Grewal, T. Ning, J. Bronzino","doi":"10.1109/NEBC.1988.19397","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19397","url":null,"abstract":"The multichannel autoregressive model and the periodogram approach are used to determine coherence and phase measures between the electrical activity in two distinct brain structures of the rat namely, the subfields CA1 and dentate gyrus in the hippocampal formation, during the vigilance states of quiet waking (QW), slow-wave sleep (SWS), and rapid-eye-movement (REM) sleep. Using both periodogram and multichannel autoregressive modeling techniques, high coherence and consistent phase differences were found to exist within the theta range of frequencies (4-11 Hz) only during REM sleep.<<ETX>>","PeriodicalId":165980,"journal":{"name":"Proceedings of the 1988 Fourteenth Annual Northeast Bioengineering Conference","volume":"11 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":"123870244","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 frameless stereotaxic operating microscope for neurosurgery is discussed. The microscope projects computed tomography (CT) information into the microscope, superposing a tumor outline or guidance to predetermined targets in the surgical field in the correct scale, position, and orientation. The transposition of data from CT to OR (operating-room) space is accomplished with a set of fiducial points which are localized in both CT and OR space, eliminating the need for conventional mechanical stereotaxic frame attached to the head of the patient. Once this transformation matrix has been determined, the operating microscope's position is monitored and information derived from the CT scan is projected into the operating microscope. A nonimaging ultrasonic rangefinder, consisting of microphones and sound emitters, enables the precise location of the sound emitters in OR space to be determined. Under computer control, one sound emitter is fired, and the distance from it to each of the microphones is determined. The operating microscope has three sound emitters attached to it, so its position and orientation can be uniquely determined. Sound emitters are placed on the fiducial points on the patient's scalp, and the CT-OR transformation is determined. In this way, an open surgical field is maintained, yet stereotaxic information and guidance is available.<>
{"title":"Improved accuracy for the frameless stereotaxic operating microscope","authors":"E. Friets, J. Strohbehn, D. Roberts","doi":"10.1109/NEBC.1988.19340","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19340","url":null,"abstract":"A frameless stereotaxic operating microscope for neurosurgery is discussed. The microscope projects computed tomography (CT) information into the microscope, superposing a tumor outline or guidance to predetermined targets in the surgical field in the correct scale, position, and orientation. The transposition of data from CT to OR (operating-room) space is accomplished with a set of fiducial points which are localized in both CT and OR space, eliminating the need for conventional mechanical stereotaxic frame attached to the head of the patient. Once this transformation matrix has been determined, the operating microscope's position is monitored and information derived from the CT scan is projected into the operating microscope. A nonimaging ultrasonic rangefinder, consisting of microphones and sound emitters, enables the precise location of the sound emitters in OR space to be determined. Under computer control, one sound emitter is fired, and the distance from it to each of the microphones is determined. The operating microscope has three sound emitters attached to it, so its position and orientation can be uniquely determined. Sound emitters are placed on the fiducial points on the patient's scalp, and the CT-OR transformation is determined. In this way, an open surgical field is maintained, yet stereotaxic information and guidance is available.<<ETX>>","PeriodicalId":165980,"journal":{"name":"Proceedings of the 1988 Fourteenth Annual Northeast Bioengineering Conference","volume":"168 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":"124248078","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}
J. C. Astbury, Michael H. Goldschmidt, Sydney M. Evans, Gert W. Niebauer, Kenneth R. Foster
The dielectric properties of normal canine spleens containing neoplastic lesions are discussed. Six splenic tumors were examined: two hemangiosarcomas, two mast cell tumors, one lymphosarcoma and one metastatic heart base tumor. The dielectric properties of the neoplastic tissues were compared to those of the nonneoplastic tissue. No significant differences between neoplastic and normal tissues are seen.<>
{"title":"The dielectric properties of canine and normal and neoplastic splenic tissues","authors":"J. C. Astbury, Michael H. Goldschmidt, Sydney M. Evans, Gert W. Niebauer, Kenneth R. Foster","doi":"10.1109/NEBC.1988.19357","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19357","url":null,"abstract":"The dielectric properties of normal canine spleens containing neoplastic lesions are discussed. Six splenic tumors were examined: two hemangiosarcomas, two mast cell tumors, one lymphosarcoma and one metastatic heart base tumor. The dielectric properties of the neoplastic tissues were compared to those of the nonneoplastic tissue. No significant differences between neoplastic and normal tissues are seen.<<ETX>>","PeriodicalId":165980,"journal":{"name":"Proceedings of the 1988 Fourteenth Annual Northeast Bioengineering Conference","volume":"208 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113953235","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}
Angiographic determinations of blood flow, based on either contrast wavefront velocity or appearance time, are subject to methodological inaccuracy. The inaccuracies due to variable injection flow rates, contrast reflux from a vessel orifice and location of the measurement site were studied in an in vitro model. Contrast boluses of varying volumes and rates were introduced into a nonpulsatile flow stream of normal saline. Variable-size venting needles were also inserted to permit controlled reflux. Transarterial flow was measured with both an electromagnetic flow probe and digital subtraction angiography. Regression equations relating angiographic and electromagnetic flow measurements to underlying steady-state saline, superimposed contrast injectate, and contrast reflux flows were obtained. More accurate angiographic measurements were obtained when the measurement site was moved away from the injection site, since this avoids the turbulent effects of the contrast injection. The results also indicate that for accurate contrast transit flow determinations, the amount of contrast injected and the friction lost in reflux, must be accounted for.<>
{"title":"Effect of contrast injection on angiographic measurements","authors":"L. Srinivasan, W. Ohley, H. White, R. Peura","doi":"10.1109/NEBC.1988.19409","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19409","url":null,"abstract":"Angiographic determinations of blood flow, based on either contrast wavefront velocity or appearance time, are subject to methodological inaccuracy. The inaccuracies due to variable injection flow rates, contrast reflux from a vessel orifice and location of the measurement site were studied in an in vitro model. Contrast boluses of varying volumes and rates were introduced into a nonpulsatile flow stream of normal saline. Variable-size venting needles were also inserted to permit controlled reflux. Transarterial flow was measured with both an electromagnetic flow probe and digital subtraction angiography. Regression equations relating angiographic and electromagnetic flow measurements to underlying steady-state saline, superimposed contrast injectate, and contrast reflux flows were obtained. More accurate angiographic measurements were obtained when the measurement site was moved away from the injection site, since this avoids the turbulent effects of the contrast injection. The results also indicate that for accurate contrast transit flow determinations, the amount of contrast injected and the friction lost in reflux, must be accounted for.<<ETX>>","PeriodicalId":165980,"journal":{"name":"Proceedings of the 1988 Fourteenth Annual Northeast Bioengineering Conference","volume":"61 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":"124377148","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 results of a structural analysis of an ankle-foot orthosis (AFO) using beam theory with results from a three-dimensional finite-element analysis are compared. Analytical results are then compared to data obtained from a controlled load test of an AFO. Conclusions drawn indicate that while beam theory accurately predicts overall reflections, the finite-element analysis correctly locates compression zones where local buckling may govern the type of failure mode.<>
{"title":"Structural analysis of solid ankle-foot orthoses","authors":"D. Leone, S. Diemente, S. Gustave, M. Lopez-Isa","doi":"10.1109/NEBC.1988.19334","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19334","url":null,"abstract":"The results of a structural analysis of an ankle-foot orthosis (AFO) using beam theory with results from a three-dimensional finite-element analysis are compared. Analytical results are then compared to data obtained from a controlled load test of an AFO. Conclusions drawn indicate that while beam theory accurately predicts overall reflections, the finite-element analysis correctly locates compression zones where local buckling may govern the type of failure mode.<<ETX>>","PeriodicalId":165980,"journal":{"name":"Proceedings of the 1988 Fourteenth Annual Northeast Bioengineering Conference","volume":"39 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":"122267320","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}
Mathematical models of the ascending and descending parts of the pressure pulse contour in the ascending aorta were previously shown to be exponential functions of time (see A. Chatterjea and J. Njock Libii, Proc. 9th Ann. Conf. IEEE Eng. in Med. and Biol. Soc., vol.2, p.868, 1987). However, in that investigation the presence of incisura was neglected. Here, a mathematical model of the incisura is presented.<>
升主动脉压力脉冲轮廓的上升和下降部分的数学模型先前被证明是时间的指数函数(见A. Chatterjea和J. Njock Libii, Proc. 9th Ann)。IEEE工程学报。医学和生物学。Soc。，第2卷，第868页，1987年)。然而，在那次调查中，切痕的存在被忽视了。本文建立了切齿的数学模型。
{"title":"Model of incisura on pressure pulse contours in the aorta","authors":"J. Libii, A. Chatterjea","doi":"10.1109/NEBC.1988.19384","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19384","url":null,"abstract":"Mathematical models of the ascending and descending parts of the pressure pulse contour in the ascending aorta were previously shown to be exponential functions of time (see A. Chatterjea and J. Njock Libii, Proc. 9th Ann. Conf. IEEE Eng. in Med. and Biol. Soc., vol.2, p.868, 1987). However, in that investigation the presence of incisura was neglected. Here, a mathematical model of the incisura is presented.<<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":"124663980","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}
This study was designed to assess the correlation between degenerate joint disease (DJD) of the lumbar spine and early peak vertical forces attenuated through the lateral calcaneus during the gait cycle. Data was collected from 18 subjects, ranging in age from 22 to 60 years, who had been radiographically diagnosed with DJD of the lumbar spine. Measurement of vertical force over time was obtained using the electrodynograph system with standardized procedure. Results demonstrate that in patients with lumbar DJD the L-sensor, positioned on the lateral condyle of the plantar surface of the calcaneus, shows peak pressures at an early percentage of stance. These results indicate improper attenuation of initial forces through the axial skeleton during the gait cycle, potentially producing chronic overloading responsible for DJD of the lumbar spine. These findings imply that clinicians should consider the effects of high impact forces on an inverted calcaneus when evaluating and treating chronic low-back-pain patients.<>
{"title":"Degenerative changes in the lumbar spin and early pes pressures","authors":"James Krzaczek, G. McNelis, J. Eisenhardt","doi":"10.1109/NEBC.1988.19336","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19336","url":null,"abstract":"This study was designed to assess the correlation between degenerate joint disease (DJD) of the lumbar spine and early peak vertical forces attenuated through the lateral calcaneus during the gait cycle. Data was collected from 18 subjects, ranging in age from 22 to 60 years, who had been radiographically diagnosed with DJD of the lumbar spine. Measurement of vertical force over time was obtained using the electrodynograph system with standardized procedure. Results demonstrate that in patients with lumbar DJD the L-sensor, positioned on the lateral condyle of the plantar surface of the calcaneus, shows peak pressures at an early percentage of stance. These results indicate improper attenuation of initial forces through the axial skeleton during the gait cycle, potentially producing chronic overloading responsible for DJD of the lumbar spine. These findings imply that clinicians should consider the effects of high impact forces on an inverted calcaneus when evaluating and treating chronic low-back-pain patients.<<ETX>>","PeriodicalId":165980,"journal":{"name":"Proceedings of the 1988 Fourteenth Annual Northeast Bioengineering Conference","volume":"631 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":"131979439","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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