Pub Date : 2002-12-01DOI: 10.1109/IEMBS.2002.1106354
P. Kerkhof, J.K. Li
Left ventricular interaction with arterial load has been described in terms of the ratio (k) of effective arterial elastance (Ea) and maximal systolic elastance (Emax). Using the definition formulas for both elastances, a linear relationship between end-systolic volume (ESV) and end-diastolic volume (EDV) can be derived. The slope of this linearity equals k/(k+1), while the intercept can be identified as Vo/(k+1) where Vo is the extrapolated volume intercept of the linearized Emax-concept. Since the ESV vs EDV relationship refers to ventricular volume regulation, we have demonstrated that its characteristics can be exclusively expressed in terms of the coupling index k and the intercept Vo. We conclude that k and Vo are important determinants of the regulation of ventricular volume.
左心室与动脉负荷的相互作用用有效动脉弹性(Ea)和最大收缩弹性(Emax)的比值(k)来描述。利用这两种弹性的定义公式，可以推导出收缩末期体积(ESV)和舒张末期体积(EDV)之间的线性关系。这个线性的斜率等于k/(k+1)，而截距可以确定为Vo/(k+1)，其中Vo是线性化emax概念的外推体积截距。由于ESV vs EDV关系是指心室容积调节，我们已经证明其特征可以用耦合指数k和截距Vo来表达。我们得出结论，k和Vo是心室容积调节的重要决定因素。
{"title":"Identification of left ventricular volume regulation on the basis of the elastance concept","authors":"P. Kerkhof, J.K. Li","doi":"10.1109/IEMBS.2002.1106354","DOIUrl":"https://doi.org/10.1109/IEMBS.2002.1106354","url":null,"abstract":"Left ventricular interaction with arterial load has been described in terms of the ratio (k) of effective arterial elastance (Ea) and maximal systolic elastance (Emax). Using the definition formulas for both elastances, a linear relationship between end-systolic volume (ESV) and end-diastolic volume (EDV) can be derived. The slope of this linearity equals k/(k+1), while the intercept can be identified as Vo/(k+1) where Vo is the extrapolated volume intercept of the linearized Emax-concept. Since the ESV vs EDV relationship refers to ventricular volume regulation, we have demonstrated that its characteristics can be exclusively expressed in terms of the coupling index k and the intercept Vo. We conclude that k and Vo are important determinants of the regulation of ventricular volume.","PeriodicalId":60385,"journal":{"name":"中国地球物理学会年刊","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89871072","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 : 2002-12-01DOI: 10.1109/IEMBS.2002.1106594
J. R. Claycomb, C. Prodan, D. Nawarathna, J.H. Miller
We report the results of nonlinear dielectric spectroscopy measurements of living cell suspensions. The experiments are carried out at low excitation frequency (kHz) and signal amplitude of several V/cm. Harmonics in the cell response are monitored after glucose is added.
{"title":"Nonlinear dielectric spectroscopy of living cell suspensions","authors":"J. R. Claycomb, C. Prodan, D. Nawarathna, J.H. Miller","doi":"10.1109/IEMBS.2002.1106594","DOIUrl":"https://doi.org/10.1109/IEMBS.2002.1106594","url":null,"abstract":"We report the results of nonlinear dielectric spectroscopy measurements of living cell suspensions. The experiments are carried out at low excitation frequency (kHz) and signal amplitude of several V/cm. Harmonics in the cell response are monitored after glucose is added.","PeriodicalId":60385,"journal":{"name":"中国地球物理学会年刊","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77852367","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 : 2002-12-01DOI: 10.1109/IEMBS.2002.1106332
D. Sodickson
Parallel magnetic resonance imaging techniques use spatial information from arrays of radiofrequency detector coils to accelerate imaging. A number of parallel MRI techniques have been described in recent years, and numerous clinical applications are currently being explored. The advent of practical parallel imaging presents various challenges for image reconstruction and RF system design.
{"title":"Breaking the speed limit in magnetic resonance imaging: an introduction to parallel MRI","authors":"D. Sodickson","doi":"10.1109/IEMBS.2002.1106332","DOIUrl":"https://doi.org/10.1109/IEMBS.2002.1106332","url":null,"abstract":"Parallel magnetic resonance imaging techniques use spatial information from arrays of radiofrequency detector coils to accelerate imaging. A number of parallel MRI techniques have been described in recent years, and numerous clinical applications are currently being explored. The advent of practical parallel imaging presents various challenges for image reconstruction and RF system design.","PeriodicalId":60385,"journal":{"name":"中国地球物理学会年刊","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77994546","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 : 2002-12-01DOI: 10.1109/IEMBS.2002.1106632
R. Patterson
An electrical impedance measuring scale (Tanita Model TBF-551) was used to make repeated estimations of the body fat of an adult male subject undergoing dietary changes that resulted in a 4.7 kg weight increase. The results showed that the body fat decreased approximately 3 kg with the weight gain. Over a period of five days of normal diet and activity the body fat change returned to the control condition. It appeared the weight gain was caused mainly by fluid changes not a body fat increase. The results suggest serious errors can occur in body fat estimates based on body impedance measurements, but use as a fluid change indicator may be possible.
{"title":"Body electrical impedance measurements: body fat or body fluid?","authors":"R. Patterson","doi":"10.1109/IEMBS.2002.1106632","DOIUrl":"https://doi.org/10.1109/IEMBS.2002.1106632","url":null,"abstract":"An electrical impedance measuring scale (Tanita Model TBF-551) was used to make repeated estimations of the body fat of an adult male subject undergoing dietary changes that resulted in a 4.7 kg weight increase. The results showed that the body fat decreased approximately 3 kg with the weight gain. Over a period of five days of normal diet and activity the body fat change returned to the control condition. It appeared the weight gain was caused mainly by fluid changes not a body fat increase. The results suggest serious errors can occur in body fat estimates based on body impedance measurements, but use as a fluid change indicator may be possible.","PeriodicalId":60385,"journal":{"name":"中国地球物理学会年刊","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78049571","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 : 2002-12-01DOI: 10.1109/IEMBS.2002.1053246
K. Lee, D. Hwang, M. Yarmush, G. Stephanopoulos
Metabolic profiling analyses were performed on metabolite measurements and intracellular fluxes obtained in liver models of injury. Classification of physiological states by projection based discrimination improved with increasing metabolite measurement number and addition of fluxes.
{"title":"Metabolic profiling: definition and use in physiological state classification","authors":"K. Lee, D. Hwang, M. Yarmush, G. Stephanopoulos","doi":"10.1109/IEMBS.2002.1053246","DOIUrl":"https://doi.org/10.1109/IEMBS.2002.1053246","url":null,"abstract":"Metabolic profiling analyses were performed on metabolite measurements and intracellular fluxes obtained in liver models of injury. Classification of physiological states by projection based discrimination improved with increasing metabolite measurement number and addition of fluxes.","PeriodicalId":60385,"journal":{"name":"中国地球物理学会年刊","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76256164","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 : 2002-12-01DOI: 10.1109/IEMBS.2002.1106369
Z. He, L. Baijens, S. Wanant, P. Shah, S. He, B. Sugimoto, M. Sacks, A. Yoganathan
Dual camera stereo photogrammetry was used to quantify the deformation of the central region of the anterior leaflet: of the mitral valve operating in a flow loop under physiological and pathological conditions. Stretches and strains were measured and analyzed. The principal stretches demonstrated a rapid rise early in leaflet closure, followed by a plateau, suggesting that the collagen fibers "locked" in place. There is a big difference between the major principal stretch and minor principal stretch. Similar to in-vitro tissue mechanics studies, the transmitral pressure-areal strain relationship during loading and unloading clearly demonstrated hysteresis. Further, this relationship demonstrated a dramatic stiffening attributed to collagen fiber locking. When the data of 3 papillary muscle positions were compared, the leaflet in the slack papillary position showed the highest areal strain rate. The valve exhibited a strongly anisotropic behavior. Papillary muscle position had a small effect on strain measured in the region.
{"title":"In vitro dynamic strain analysis on porcine mitral valve","authors":"Z. He, L. Baijens, S. Wanant, P. Shah, S. He, B. Sugimoto, M. Sacks, A. Yoganathan","doi":"10.1109/IEMBS.2002.1106369","DOIUrl":"https://doi.org/10.1109/IEMBS.2002.1106369","url":null,"abstract":"Dual camera stereo photogrammetry was used to quantify the deformation of the central region of the anterior leaflet: of the mitral valve operating in a flow loop under physiological and pathological conditions. Stretches and strains were measured and analyzed. The principal stretches demonstrated a rapid rise early in leaflet closure, followed by a plateau, suggesting that the collagen fibers \"locked\" in place. There is a big difference between the major principal stretch and minor principal stretch. Similar to in-vitro tissue mechanics studies, the transmitral pressure-areal strain relationship during loading and unloading clearly demonstrated hysteresis. Further, this relationship demonstrated a dramatic stiffening attributed to collagen fiber locking. When the data of 3 papillary muscle positions were compared, the leaflet in the slack papillary position showed the highest areal strain rate. The valve exhibited a strongly anisotropic behavior. Papillary muscle position had a small effect on strain measured in the region.","PeriodicalId":60385,"journal":{"name":"中国地球物理学会年刊","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74171189","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 : 2002-12-01DOI: 10.1109/IEMBS.2002.1134527
V. K. Thomas, Jianhua Wu, C. Zhu, Michael Loran Dustin
We have applied a new method for measuring two dimensional kinetic rates to the study the interactions between receptor important for the regulation of the immune response. The interaction of Cluster of Differentiation (CD) 28 with CD80 stimulates T cell activation, while the interaction of Cytotoxic T Lymphocyte Antigen (CTLA)-4 with CD80 is an antagonist to T cell activation. The new analysis provides information about free ligand diffusion in the contact area, the fraction of interactions that are stable and the kinetic off-rate. Independent data from equilibrium measurements are used to calculate the on-rate. The values for CD28-CD80 interaction reveal a 10-fold reduction in free CD80 diffusion, a small stable fraction of 9.6% and a 2D k/sub r/ of 0.057 s/sup -1/. This compares to an off-rate of 1.6 s/sup -1/ in solution, a difference of 30-fold. The CTLA-4-CD28 system is under analysis, but appears to have slower kinetics, requiring very long recovery time courses for analysis.
{"title":"Dynamics of surface receptor interactions required for an immune response","authors":"V. K. Thomas, Jianhua Wu, C. Zhu, Michael Loran Dustin","doi":"10.1109/IEMBS.2002.1134527","DOIUrl":"https://doi.org/10.1109/IEMBS.2002.1134527","url":null,"abstract":"We have applied a new method for measuring two dimensional kinetic rates to the study the interactions between receptor important for the regulation of the immune response. The interaction of Cluster of Differentiation (CD) 28 with CD80 stimulates T cell activation, while the interaction of Cytotoxic T Lymphocyte Antigen (CTLA)-4 with CD80 is an antagonist to T cell activation. The new analysis provides information about free ligand diffusion in the contact area, the fraction of interactions that are stable and the kinetic off-rate. Independent data from equilibrium measurements are used to calculate the on-rate. The values for CD28-CD80 interaction reveal a 10-fold reduction in free CD80 diffusion, a small stable fraction of 9.6% and a 2D k/sub r/ of 0.057 s/sup -1/. This compares to an off-rate of 1.6 s/sup -1/ in solution, a difference of 30-fold. The CTLA-4-CD28 system is under analysis, but appears to have slower kinetics, requiring very long recovery time courses for analysis.","PeriodicalId":60385,"journal":{"name":"中国地球物理学会年刊","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74493368","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 : 2002-12-01DOI: 10.1109/IEMBS.2002.1136925
S. Mcguire, F. Yuan
Interstitial penetration is critical for drug delivery in tumor tissues. To experimentally determine the penetration depth of macromolecules at the steady state, rat fibrosarcoma tissues were sectioned into 600 /spl mu/m slices and incubated in solutions of dextrans with molecular weights of 10 kDa, 70 kDa, and 2000 kDa, respectively. After incubation, 10 /spl mu/m cross-sections were taken and imaged to determine normalized steady-state concentration profiles as a function of molecular size. 10 kDa dextran had a relatively uniform concentration distribution. However, the concentration profile was nonuniform for 70 kDa dextran and the least uniform for 2000 kDa dextran. Stretching or incubation of tissues in 1 M mannitol solution improved the penetration of macromolecules in tissues. These results indicate that creating more interstitial space by either stretching or reducing cell size improves macromolecule distribution in tissues.
{"title":"Effects of tissue stretching or cell shrinkage on penetration depth of macromolecules in a rat fibrosarcoma","authors":"S. Mcguire, F. Yuan","doi":"10.1109/IEMBS.2002.1136925","DOIUrl":"https://doi.org/10.1109/IEMBS.2002.1136925","url":null,"abstract":"Interstitial penetration is critical for drug delivery in tumor tissues. To experimentally determine the penetration depth of macromolecules at the steady state, rat fibrosarcoma tissues were sectioned into 600 /spl mu/m slices and incubated in solutions of dextrans with molecular weights of 10 kDa, 70 kDa, and 2000 kDa, respectively. After incubation, 10 /spl mu/m cross-sections were taken and imaged to determine normalized steady-state concentration profiles as a function of molecular size. 10 kDa dextran had a relatively uniform concentration distribution. However, the concentration profile was nonuniform for 70 kDa dextran and the least uniform for 2000 kDa dextran. Stretching or incubation of tissues in 1 M mannitol solution improved the penetration of macromolecules in tissues. These results indicate that creating more interstitial space by either stretching or reducing cell size improves macromolecule distribution in tissues.","PeriodicalId":60385,"journal":{"name":"中国地球物理学会年刊","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74656965","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 : 2002-12-01DOI: 10.1109/IEMBS.2002.1134487
C. Choi, Y.P. Chen
Although there are a lot of studies of the cochlear implant, there is no study directly compare the current focus performance and the neural excitation patterns of different cochlear implant electrode design. Volume conduction analyses using 3D finite element method and nerve fiber model were used to evaluate the neural excitation patterns of the ball electrodes, banded electrodes, half banded electrodes, and planar electrodes for the first half turn of a human cochlea model for monopolar, common mode, bipolar, and tripolar stimulating modes.
{"title":"Neural excitation patterns of four cochlear implant electrode array configurations","authors":"C. Choi, Y.P. Chen","doi":"10.1109/IEMBS.2002.1134487","DOIUrl":"https://doi.org/10.1109/IEMBS.2002.1134487","url":null,"abstract":"Although there are a lot of studies of the cochlear implant, there is no study directly compare the current focus performance and the neural excitation patterns of different cochlear implant electrode design. Volume conduction analyses using 3D finite element method and nerve fiber model were used to evaluate the neural excitation patterns of the ball electrodes, banded electrodes, half banded electrodes, and planar electrodes for the first half turn of a human cochlea model for monopolar, common mode, bipolar, and tripolar stimulating modes.","PeriodicalId":60385,"journal":{"name":"中国地球物理学会年刊","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80855386","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 : 2002-12-01DOI: 10.1109/IEMBS.2002.1053292
T. Akkin, H. Rylander, D. Dave, T. Milner
A fiber based dual channel phase-sensitive optical low coherence tomography system is proposed for birefringence imaging neural tissues. The system measures relative optical path length differences between the orthogonal modes of the polarization-maintaining fiber in highly scattering media with high lateral and longitudinal spatial resolution. Because of the ability of detecting ultra-small changes in refractive index, system has uses in many bio-medical optical imaging applications such as monitoring cell and tissue dynamics, imaging of phase objects, and functional studies.
{"title":"Fiber-based phase-sensitive optical low coherence reflectometer for birefringence imaging of nerves","authors":"T. Akkin, H. Rylander, D. Dave, T. Milner","doi":"10.1109/IEMBS.2002.1053292","DOIUrl":"https://doi.org/10.1109/IEMBS.2002.1053292","url":null,"abstract":"A fiber based dual channel phase-sensitive optical low coherence tomography system is proposed for birefringence imaging neural tissues. The system measures relative optical path length differences between the orthogonal modes of the polarization-maintaining fiber in highly scattering media with high lateral and longitudinal spatial resolution. Because of the ability of detecting ultra-small changes in refractive index, system has uses in many bio-medical optical imaging applications such as monitoring cell and tissue dynamics, imaging of phase objects, and functional studies.","PeriodicalId":60385,"journal":{"name":"中国地球物理学会年刊","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74545435","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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