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B. Tsai, E. Birgersson and U. Birgersson

= [0, 0, αV 0 , V 0 ] T ): I 1 = V 0 D ( − A 12 A 23 + A 33 A 12 − A 32 A 13A 23 α A 42 + A 13 α A 42 − A 13 α A 22 − A 12 A 43 α + A 12 A 23 α     + A 43 α A 22 + A 32 A 23 − A 33 A 22 + A 13 A 22 ) , $$\begin{array}{} I_{1}=\displaystyle \frac{V_{0}}{D}(-A_{12}A_{23}+A_{33}A_{12}-A_{32}A_{13}-A_{23}\alpha A_{42}\\ \quad+A_{13}\alpha A_{42}-A_{13}\alpha A_{22}-A_{12}A_{43}\alpha+A_{12}A_{23}\alpha\\ \quad~~+A_{43}\alpha A_{22}+A_{32}A_{23}-A_{33}A_{22}+A_{13}A_{22})\ , \end{array}$$ (83) I 2 = − V 0 D ( A 11 A 33 − A 11 A 43 α − A 11 A 23 + A 11 A 23

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B. Tsai, H. Xue, E. Birgersson, S. Ollmar and U. Birgersson

reduced model, outlined in Appendix B. The reduced model is then solved with a Hankel transform (see Appendix C), resulting in the following approximate analytical solution for the predicted impedance, Z l , for a given depth setting l : (2) Z l = A 33 A 41 A 12 − A 33 A 41 A 22 − A 13 A 21 A 42 + − A 31 A

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Dejan Križaj and Borut Pečar

already by Geddes [ 2 ] and is covered in several books [ 12 , 13 , 14 ]. Mostly, the phenomena is explained and discussed through a dispersion of relaxation times that can be described by the Cole-Cole model or similar equations. In our investigation we modeled the electrode/electrolyte “capacitor” as a series combination of a resistor and a constant phase element. More sophisticated models could possibly improve the fitting error but at the price of added complexity. The procedure used in this research is cumbersome to a certain extent as it involves mechanically

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Tushar Kanti Bera, Nagaraju Jampana and Gilles Lubineau

distinguish real from imaginary parts of bioimpedance and serve as a guide to define equivalent electrical circuit parameters. Because equivalent electrical circuit models or equivalent circuit models (ECM) [ 6 , 13 ] are very useful for understanding the anatomical, physiological and compositional aspects of biological tissues, an accurate analysis of data plots is required for effective assessment of a tissue’s properties. Impedance analyzers are used either to measure the electrical impedance of materials at a single frequency or to study impedance variation over a

Open access

C. Canali, K. Aristovich, L. Ceccarelli, L.B Larsen, Ø. G. Martinsen, A. Wolff, M. Dufva, J. Emnéus and A. Heiskanen

electrode pairs. Both impedance [ 4 ] or changes in impedance with time [ 5 ] or frequency [ 6 ] have been imaged in different fields, spanning from geological studies [ 7 ] to medical research [ 8 ]. The main advantages of EIT in medicine and biology are non-invasiveness, low cost and good temporal resolution [ 9 , 10 ]. It has been applied for diagnosis of a number of pathological conditions, such as breast cancer [ 11 , 12 ] and stroke [ 13 , 14 ], but also for monitoring brain function [ 15 , 16 ], lung ventilation [ 17 , 18 ] and gastric emptying [ 19 , 20

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T. Schlebusch, J. Orschulik, J. Malmivuo, S. Leonhardt, D. Leonhäuser, J. Grosse, M. Kowollik, R. Kirschner-Hermanns and M. Walter

cystovolumetry has been reported by our group in 2011 [ 7 ]. In this study, nine male paraplegic patients have been monitored by EIT during regular urodynamic examination. A total volume of 99–585 ml contrast agent (conductivity of 13.35 mS/cm) has been instilled. An elastic electrode belt of 16 conductive silicone electrodes has been attached to the lower torso of the patient and an experimental EIT System (EEK2, Dr¨ager Medical, Lübeck, Germany) was connected for impedance measurement. The device uses adjacent injection and measurement patterns, which means that neighbouring

Open access

Tushar Kanti Bera and J. Nagaraju

-11 Mean Nyquist plots: (a) R Muscle Paste vs -X Muscle Paste , (b) R Fat vs -X Fat . It is observed that, STDV of Z Muscle Paste ( Fig.-12a) , θ Muscle Paste ( Fig.-12b) , R Muscle Paste ( Fig.-12c ) and X Muscle Paste ( Fig.-12d ) are less than the STDV of the corresponding impedance parameters of the fat tissue. STDV of the θMuscle Paste is found to be higher than the STDV of the θ Fat up to 100 kHz. It is also observed that the MDR of Z Muscle Paste ( Fig.-13a ), θ Muscle Paste ( Fig.-13b) , R Muscle Paste ( Fig.-13c ) and X Muscle Paste

Open access

O. Wahlsten and P. Apell

the basic response properties. In this aspect we can consider the presence of a wound as a perturbation and by studying this gain information about the electrical properties of the unwounded skin. Recently Nuccitelli et al. [ 13 , 14 ] measured the potential in the wound area of mice and humans using a non-invasive vibrating probe. These experimental results will be compared with our model of the skin. Main factors which determine the field strength in skin are dielectric permittivities and geometrical factors. With a detailed knowledge of the electrical

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Leo Koziol, John J. Pitre, Joseph L. Bull, Robert E. Dodde, Grant Kruger, Alan Vollmer and William F. Weitzel

improvements in assessment and management of fluid status essential [ 12 , 13 ]. We therefore are investigating a quantitative approach to assess edema using a modification of conventional segmental BIS methods [ 14 , 15 , 16 ]. BIS measurements have been used in various ways to improve the assessment of dry weight in dialysis [ 10 , 17 , 18 ]. Fig. 1 shows graphically the principle behind how the flattening of BIS over time can be used to estimate the arrival at a near-dry weight status in dialysis patients. Dry-weight in dialysis has been conventionally defined as

Open access

Barry Belmont, Robert E. Dodde and Albert J. Shih

admittance (like their corresponding stress counterparts) were found to be constant throughout each of the levels of strain tested. However, these variables are slightly misleading, as we have introduced a pair of concepts (an elastic modulus for admittance, E Y , and a time constant of admittance relaxation, τ R ,Y ) for which there is no basis aside from mathematical convenience. However, E Y and τ R ,Y can be expressed wholly in terms of mechanical deformation by postulating: (13) E Y E σ = f ( ε 0 ) $$\frac{{{E}_{Y}}}{{{E}_{\sigma }}}=f