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Michael F. Insana - One of the best experts on this subject based on the ideXlab platform.
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Complex Shear Modulus Estimation using Maximum Likelihood Ensemble Filters
IFMBE Proceedings, 2013Co-Authors: Tan Tran-duc, Yue Wang, Nguyen Linh-trung, Minh N., Michael F. InsanaAbstract:Ultrasound Shear wave imaging can be used to estimate quantitative information about soft tissue mechanical properties, specifically the Complex Shear Modulus (CSM). It is promising because it has the potential to bridge molecular, cellular, and tissue biology and to support for medical diagnoses. However, there is a lack of efficient methods for CSM estimation due to high Complexity and low reconstruction’s quality. To overcome these disadvantages, in this paper, we have applied the Bayesian-approach-based Maximum Likelihood Ensemble Filter (MLEF) for CSM estimation. The error performance is below 10%. Both simulated and experimental data were tested in order to assess the proposed method.
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3-D FDTD simulation of Shear waves for evaluation of Complex Modulus imaging
IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control, 2011Co-Authors: Marko Orescanin, Yue Wang, Michael F. InsanaAbstract:The Navier equation describing Shear wave propagation in 3-D viscoelastic media is solved numerically with a finite differences time domain (FDTD) method. Solutions are formed in terms of transverse scatterer velocity waves and then verified via comparison to measured wave fields in heterogenous hydrogel phantoms. The numerical algorithm is used as a tool to study the effects on Complex Shear Modulus estimation from wave propagation in heterogeneous viscoelastic media. We used an algebraic Helmholtz inversion (AHI) technique to solve for the Complex Shear Modulus from simulated and experimental velocity data acquired in 2-D and 3-D. Although 3-D velocity estimates are required in general, there are object geometries for which 2-D inversions provide accurate estimations of the material properties. Through simulations and experiments, we explored artifacts generated in elastic and dynamic-viscous Shear Modulus images related to the Shear wavelength and average viscosity.
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Model-based Complex Shear Modulus reconstruction: A Bayesian approach
2010 IEEE International Ultrasonics Symposium, 2010Co-Authors: Marko Orescanin, Michael F. InsanaAbstract:A narrow-band ultrasonic Shear-wave imaging technique for estimating the Complex Shear Modulus was applied to gelatin phantoms. This Bayesian approach incorporates the spatiotemporal geometry of Shear waves radiating from a vibrating needle into a method for estimating Modulus parameters. Compared to the phase gradient approach, this Bayesian method provides viscoelastic reconstructions for a single Shear wave frequency. Estimates compare closely to results obtained using phase gradient method but with higher spectral resolution. We validated the assumption that the Kelvin-Voigt model, commonly applied in elasticity imaging situations, is representative of gelatin dispersion within the testing bandwidth between 50 and 450 Hz.
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Shear Modulus estimation with vibrating needle stimulation
IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control, 2010Co-Authors: Marko Orescanin, Michael F. InsanaAbstract:An ultrasonic Shear wave imaging technique is being developed for estimating the Complex Shear Modulus of biphasic hydropolymers including soft biological tissues. A needle placed in the medium is vibrated along its axis to generate harmonic Shear waves. Doppler pulses synchronously track particle motion to estimate Shear wave propagation speed. Velocity estimation is improved by implementing a k-lag phase estimator. Fitting Shear-wave speed estimates to the predicted dispersion relation curves obtained from two rheological models, we estimate the elastic and viscous components of the Complex Shear Modulus. The dispersion equation estimated using the standard linear solid-body (Zener) model is compared with that from the Kelvin-Voigt model to estimate moduli in gelatin gels in the 50 to 450 Hz Shear wave frequency bandwidth. Both models give comparable estimates that agree with independent Shear rheometer measurements obtained at lower strain rates.
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quantitative estimation of Complex Shear Modulus of liver and hydrogels through Shear wave imaging
Journal of the Acoustical Society of America, 2009Co-Authors: Marko Orescanin, Muqeem A. Qayyum, Kathleen S. Toohey, Michael F. InsanaAbstract:A Doppler‐based Shear‐wave imaging technique is described for estimating the Complex Shear Modulus (μ+iωη) at Shear‐wave frequencies between 50 and 450 Hz. The developed technique involves a mechanical actuator that harmonically drives a stainless steel biopsy needle placed in the medium. Narrowband cylindrical Shear waves are imaged using pulsed Doppler techniques. Shear moduli were computed from Doppler detected velocity. A phase gradient technique is applied to measure Shear‐wave speed. Spatially averaged speeds were numerically fit to a mathematical model relating dispersion and Complex Modulus. The proposed method was used to estimate Complex Shear Modulus of the homogeneous three dimensional collagen hydrogels and of fresh and thermally‐damaged porcine liver. The elastic Shear Modulus of 4% collagen hydrogel was measured, μ=640±14 Pa, using a commercial rheometer as a standard. The phase gradient approach yielded frequency‐independent moduli μ=570±67 Pa and η=0.16±0.09 Pa s. For fresh liver Shear‐wa...
Takaharu Okajima - One of the best experts on this subject based on the ideXlab platform.
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temporal change in Complex Shear Modulus of cells an atomic force microscopy study
International Symposium on Micro-NanoMechatronics and Human Science, 2014Co-Authors: Pinggen Cai, Ryosuke Takahashi, Kaori Kuribayashishigetomi, Agus Subagyo, Kazuhisa Sueoka, Takaharu OkajimaAbstract:To sort living cells according to our needs, it is important to understand how degree cell property measured for cell sorting fluctuates in time. Mechanical property of cells is one of essential indicators for cell sorting. Thus, in this study, we attempted to measure a time evolution of viscoelastic property such as Complex Shear Modulus, G∗ of single cells adhered on substrates using atomic force microscopy (AFM). We observed that the G∗ largely fluctuated in time even the cells are placed on substrates in a confined condition. This indicates that in mechanical cell sorting, mechanical fluctuations of cells should be carefully estimated so that cells are precisely separated by taking the measured data involving cell fluctuations into account.
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MHS - Temporal change in Complex Shear Modulus of cells: An atomic force microscopy study
2014 International Symposium on Micro-NanoMechatronics and Human Science (MHS), 2014Co-Authors: Pinggen Cai, Ryosuke Takahashi, Agus Subagyo, Kazuhisa Sueoka, Kaori Kuribayashi-shigetomi, Takaharu OkajimaAbstract:To sort living cells according to our needs, it is important to understand how degree cell property measured for cell sorting fluctuates in time. Mechanical property of cells is one of essential indicators for cell sorting. Thus, in this study, we attempted to measure a time evolution of viscoelastic property such as Complex Shear Modulus, G∗ of single cells adhered on substrates using atomic force microscopy (AFM). We observed that the G∗ largely fluctuated in time even the cells are placed on substrates in a confined condition. This indicates that in mechanical cell sorting, mechanical fluctuations of cells should be carefully estimated so that cells are precisely separated by taking the measured data involving cell fluctuations into account.
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Change in the Number Distribution of Complex Shear Modulus of Single Cells by Actin Cytoskeleton Modifications Measured by Atomic Force Microscopy
Biophysical Journal, 2011Co-Authors: Pinggen Cai, Yusuke Mizutani, Masahiro Tsuchiya, Koichi Kawahara, Takaharu OkajimaAbstract:The rheological properties of living cells strongly depend on their cytoskeletal structures, which are composed of polymer networks and responsible for fundamental cellular functions. In particular, the actin network plays a major role in determining the rheological properties of living cells. In order to elucidate how the rheological properties of individual cells are affected by actin filamentous structures, we measured the number distribution of Complex Shear Modulus of single cells, which were treated by actin modification drugs and cultured on microarray substrates, by atomic force microscopy. A force modulation mode experiment was employed to measure the Complex Shear Modulus of single cells in a frequency range of 2-200Hz. When the cells were treated with actin-stabilizing drug, jasplakinolide, and actin-disrupting drug, cytochalasin D (CD), the storage Modulus G’ and loss Modulus G” increased and decreased, respectively. The changes in G” were smaller comparing to those in G’. The moduli exhibited a weak power-law dependence on frequency [1], whereas the increasing and decreasing of G’ and G” were accompanied by a decreasing and increasing power-law exponent respectively. Furthermore, their corresponding logarithmic standard deviation σ showed a slight change in the case of jasplakinolide treatment whereas it became small and attained a constant value at higher frequencies in CD treatment [2]. The results indicated that individual differences of cell rheology enhanced as actin cytoskeletal structures were stabilized. Furthermore, it was implied that the observed frequency dependence of σ was attributed to a frequency susceptibility of actin filaments.[1] B. Fabry et al., Phys. Rev. E., vol. 68, pp. 041914-041917, 2003.[2] S. Hiratsuka et al., Ultramicroscopy, vol. 109, pp. 937-941, 2009.
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The number distribution of Complex Shear Modulus of single cells measured by atomic force microscopy.
Ultramicroscopy, 2009Co-Authors: Shinichiro Hiratsuka, Yusuke Mizutani, Masahiro Tsuchiya, Koichi Kawahara, Hiroshi Tokumoto, Takaharu OkajimaAbstract:Abstract The viscoelastic properties of a large number of mouse fibroblast NIH3T3 cells (n≃130) were investigated by combining atomic force microscopy (AFM) with a microarray technique. In the experiments, the cells were arranged and cultured in the wells of a microarray substrate, and a force modulation mode experiment was used to measure the Complex Shear Modulus, G*, of individual cells in a frequency range 0.5–200 Hz. The frequency dependence of G* of the cells exhibited a power-law behavior and similar frequency dependencies have been observed in several cell types cultured on flat substrates. This indicated that the NIH3T3 cells cultured in the wells of a microarray have analogous structural organization to those cells cultured on flat substrates. The number distribution of both the storage and loss moduli of G* fitted well to a log-normal distribution function, whereas the power-law exponent estimated by a power-law structural damping model showed a normal distribution function. These results showed that combining AFM with a microarray technique was a suitable approach for investigating the statistics of rheological properties of living cells without the requirement of cell surface modification.
Marko Orescanin - One of the best experts on this subject based on the ideXlab platform.
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3-D FDTD simulation of Shear waves for evaluation of Complex Modulus imaging
IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control, 2011Co-Authors: Marko Orescanin, Yue Wang, Michael F. InsanaAbstract:The Navier equation describing Shear wave propagation in 3-D viscoelastic media is solved numerically with a finite differences time domain (FDTD) method. Solutions are formed in terms of transverse scatterer velocity waves and then verified via comparison to measured wave fields in heterogenous hydrogel phantoms. The numerical algorithm is used as a tool to study the effects on Complex Shear Modulus estimation from wave propagation in heterogeneous viscoelastic media. We used an algebraic Helmholtz inversion (AHI) technique to solve for the Complex Shear Modulus from simulated and experimental velocity data acquired in 2-D and 3-D. Although 3-D velocity estimates are required in general, there are object geometries for which 2-D inversions provide accurate estimations of the material properties. Through simulations and experiments, we explored artifacts generated in elastic and dynamic-viscous Shear Modulus images related to the Shear wavelength and average viscosity.
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Model-based Complex Shear Modulus reconstruction: A Bayesian approach
2010 IEEE International Ultrasonics Symposium, 2010Co-Authors: Marko Orescanin, Michael F. InsanaAbstract:A narrow-band ultrasonic Shear-wave imaging technique for estimating the Complex Shear Modulus was applied to gelatin phantoms. This Bayesian approach incorporates the spatiotemporal geometry of Shear waves radiating from a vibrating needle into a method for estimating Modulus parameters. Compared to the phase gradient approach, this Bayesian method provides viscoelastic reconstructions for a single Shear wave frequency. Estimates compare closely to results obtained using phase gradient method but with higher spectral resolution. We validated the assumption that the Kelvin-Voigt model, commonly applied in elasticity imaging situations, is representative of gelatin dispersion within the testing bandwidth between 50 and 450 Hz.
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Shear Modulus estimation with vibrating needle stimulation
IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control, 2010Co-Authors: Marko Orescanin, Michael F. InsanaAbstract:An ultrasonic Shear wave imaging technique is being developed for estimating the Complex Shear Modulus of biphasic hydropolymers including soft biological tissues. A needle placed in the medium is vibrated along its axis to generate harmonic Shear waves. Doppler pulses synchronously track particle motion to estimate Shear wave propagation speed. Velocity estimation is improved by implementing a k-lag phase estimator. Fitting Shear-wave speed estimates to the predicted dispersion relation curves obtained from two rheological models, we estimate the elastic and viscous components of the Complex Shear Modulus. The dispersion equation estimated using the standard linear solid-body (Zener) model is compared with that from the Kelvin-Voigt model to estimate moduli in gelatin gels in the 50 to 450 Hz Shear wave frequency bandwidth. Both models give comparable estimates that agree with independent Shear rheometer measurements obtained at lower strain rates.
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quantitative estimation of Complex Shear Modulus of liver and hydrogels through Shear wave imaging
Journal of the Acoustical Society of America, 2009Co-Authors: Marko Orescanin, Muqeem A. Qayyum, Kathleen S. Toohey, Michael F. InsanaAbstract:A Doppler‐based Shear‐wave imaging technique is described for estimating the Complex Shear Modulus (μ+iωη) at Shear‐wave frequencies between 50 and 450 Hz. The developed technique involves a mechanical actuator that harmonically drives a stainless steel biopsy needle placed in the medium. Narrowband cylindrical Shear waves are imaged using pulsed Doppler techniques. Shear moduli were computed from Doppler detected velocity. A phase gradient technique is applied to measure Shear‐wave speed. Spatially averaged speeds were numerically fit to a mathematical model relating dispersion and Complex Modulus. The proposed method was used to estimate Complex Shear Modulus of the homogeneous three dimensional collagen hydrogels and of fresh and thermally‐damaged porcine liver. The elastic Shear Modulus of 4% collagen hydrogel was measured, μ=640±14 Pa, using a commercial rheometer as a standard. The phase gradient approach yielded frequency‐independent moduli μ=570±67 Pa and η=0.16±0.09 Pa s. For fresh liver Shear‐wa...
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Complex Shear Modulus of thermally-damaged liver
2009 IEEE International Ultrasonics Symposium, 2009Co-Authors: Marko Orescanin, Muqeem A. Qayyum, Kathleen S. Toohey, Michael F. InsanaAbstract:The Complex Shear Modulus of fresh and thermally damaged porcine liver has been measured, in vitro, using an ultrasonic Shear wave imaging technique. Measurements were compared to two constitutive models, Kelvin-Voigt and Zener, to estimate the Complex Modulus of liver for Shear wave frequencies between 50 and 300 Hz. An axially vibrated needle placed in the liver excites harmonic Shear waves that are imaged using a pulsed Doppler technique. Liver heated to 47°C for 90 min was found to have little measurable cellular damage, and yet the elastic Shear Modulus increased by a factor of two and the viscous Shear Modulus increased by a factor of three in this frequency range. These observations imply that elastic properties, especially the viscous Shear Modulus, may be a sensitive indicator of thermal damage. Also, within the testing bandwidth for Shear waves, the Zener model represented the data better than the Kelvin-Voigt model.
O. Surel - One of the best experts on this subject based on the ideXlab platform.
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Complex Shear Modulus determination in a large range of frequency by interconversion of the compliance for a starch/gluten blend [Détermination du module Complexe de cisaillement dans un domaine élargi de fréquence pour un mélange gluten-amidon par i
2002Co-Authors: F. Errera, Christophe Derail, Frédéric Leonardi, O. SurelAbstract:Starch/gluten/water blends have been tested on a controlled stress rotational rheometer at room temperature. Rheological characterization of these blends was performed by measuring the Complex Shear Modulus G* as a function of frequency at various water contents. For one of the blends we have performed a transient test by measuring the compliance, J, as a function of time. A Fourier transform has been applied to the function J(t) and we established a good correlation between the results of the dynamic test and of the transient test. This interconversion led to observe a cross over between G′ and G″ in the terminal zone never described in the litterature for doughs.
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Complex Shear Modulus determination in a large range of frequency by interconversion of the compliance for a starch gluten blend determination du module Complexe de cisaillement dans un domaine elargi de frequence pour un melange gluten amidon par in
2002Co-Authors: F. Errera, Christophe Derail, Frédéric Leonardi, O. SurelAbstract:Starch/gluten/water blends have been tested on a controlled stress rotational rheometer at room temperature. Rheological characterization of these blends was performed by measuring the Complex Shear Modulus G* as a function of frequency at various water contents. For one of the blends we have performed a transient test by measuring the compliance, J, as a function of time. A Fourier transform has been applied to the function J(t) and we established a good correlation between the results of the dynamic test and of the transient test. This interconversion led to observe a cross over between G′ and G″ in the terminal zone never described in the litterature for doughs.
Pinggen Cai - One of the best experts on this subject based on the ideXlab platform.
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temporal change in Complex Shear Modulus of cells an atomic force microscopy study
International Symposium on Micro-NanoMechatronics and Human Science, 2014Co-Authors: Pinggen Cai, Ryosuke Takahashi, Kaori Kuribayashishigetomi, Agus Subagyo, Kazuhisa Sueoka, Takaharu OkajimaAbstract:To sort living cells according to our needs, it is important to understand how degree cell property measured for cell sorting fluctuates in time. Mechanical property of cells is one of essential indicators for cell sorting. Thus, in this study, we attempted to measure a time evolution of viscoelastic property such as Complex Shear Modulus, G∗ of single cells adhered on substrates using atomic force microscopy (AFM). We observed that the G∗ largely fluctuated in time even the cells are placed on substrates in a confined condition. This indicates that in mechanical cell sorting, mechanical fluctuations of cells should be carefully estimated so that cells are precisely separated by taking the measured data involving cell fluctuations into account.
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MHS - Temporal change in Complex Shear Modulus of cells: An atomic force microscopy study
2014 International Symposium on Micro-NanoMechatronics and Human Science (MHS), 2014Co-Authors: Pinggen Cai, Ryosuke Takahashi, Agus Subagyo, Kazuhisa Sueoka, Kaori Kuribayashi-shigetomi, Takaharu OkajimaAbstract:To sort living cells according to our needs, it is important to understand how degree cell property measured for cell sorting fluctuates in time. Mechanical property of cells is one of essential indicators for cell sorting. Thus, in this study, we attempted to measure a time evolution of viscoelastic property such as Complex Shear Modulus, G∗ of single cells adhered on substrates using atomic force microscopy (AFM). We observed that the G∗ largely fluctuated in time even the cells are placed on substrates in a confined condition. This indicates that in mechanical cell sorting, mechanical fluctuations of cells should be carefully estimated so that cells are precisely separated by taking the measured data involving cell fluctuations into account.
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Change in the Number Distribution of Complex Shear Modulus of Single Cells by Actin Cytoskeleton Modifications Measured by Atomic Force Microscopy
Biophysical Journal, 2011Co-Authors: Pinggen Cai, Yusuke Mizutani, Masahiro Tsuchiya, Koichi Kawahara, Takaharu OkajimaAbstract:The rheological properties of living cells strongly depend on their cytoskeletal structures, which are composed of polymer networks and responsible for fundamental cellular functions. In particular, the actin network plays a major role in determining the rheological properties of living cells. In order to elucidate how the rheological properties of individual cells are affected by actin filamentous structures, we measured the number distribution of Complex Shear Modulus of single cells, which were treated by actin modification drugs and cultured on microarray substrates, by atomic force microscopy. A force modulation mode experiment was employed to measure the Complex Shear Modulus of single cells in a frequency range of 2-200Hz. When the cells were treated with actin-stabilizing drug, jasplakinolide, and actin-disrupting drug, cytochalasin D (CD), the storage Modulus G’ and loss Modulus G” increased and decreased, respectively. The changes in G” were smaller comparing to those in G’. The moduli exhibited a weak power-law dependence on frequency [1], whereas the increasing and decreasing of G’ and G” were accompanied by a decreasing and increasing power-law exponent respectively. Furthermore, their corresponding logarithmic standard deviation σ showed a slight change in the case of jasplakinolide treatment whereas it became small and attained a constant value at higher frequencies in CD treatment [2]. The results indicated that individual differences of cell rheology enhanced as actin cytoskeletal structures were stabilized. Furthermore, it was implied that the observed frequency dependence of σ was attributed to a frequency susceptibility of actin filaments.[1] B. Fabry et al., Phys. Rev. E., vol. 68, pp. 041914-041917, 2003.[2] S. Hiratsuka et al., Ultramicroscopy, vol. 109, pp. 937-941, 2009.