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A fast method to estimate body capacitance to ground at mid frequencies

measurements, either bipolar with direct contact [ 13 ] or capacitive electrodes [ 16 ], or tetrapolar [ 10 ] warrant the interest of its measurement. Measurement method In a scenario where bipolar impedances are measured on the human body, we propose to estimate the capacitance from the body to ground by connecting a known capacitor between each electrode and the impedance analyzer. Figure 2 shows the resulting equivalent circuit. If the capacitance of the added capacitors C is small enough for its impedance to be much larger than that of the body and the

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Rectifying memristor bridge circuit realized with human skin

three times for different frequencies (0.005 Hz, 0.05 Hz and 0.5 Hz) in randomized order. The time between runs during which no voltage was applied was 4 seconds. Instrumentation A custom-built measurement system (see Fig. 1c top) was used for the recordings. A data acquisition card (DAQ) (type USB-6356 from National instruments) enabled the application of two constant voltages and simultaneous reading (both was performed with 500 samples per period). The DAQ was connected to a personal computer and controlled by a custom-made software, which was written in NI

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A new system for measuring electrical conductivity of water as a function of admittance

frequencies (0.05, 2, 20, 60 and 100 kHz) for the 2-inner electrodes system. Table (2) Calculated values of admittance and measured conductivity for different frequencies by the two-inner electrode system 2-Inner Electrodes f = 0.05 kHz f = 2 kHz f = 20 kHz f = 60 kHz f = 100 kHz Admittance (μS) Conductivity (μS/cm) Admittance (μS) Conductivity (μS/cm) Admittance (μS) Conductivity (μS/cm) Admittance (μS) Conductivity (μS/cm) Admittance (μS) Conductivity (μS/cm) Distilled Water 2.91 16.20 3.77 16.20 10.38 16

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Relating membrane potential to impedance spectroscopy

, the permittivity spectra present a clear dependency of α dispersion on the membrane potential. However, for cells with radius ~2 μm, the spectra of impedance magnitude relative to the value at 1 kHz (impedance level prior to β dispersion) reveal ( fig. 1B) very small decrements related to α dispersion, ΔZr ≤ 5×10 -3 % raising tough experimental constraints. The same challenge is related to phase variations in the α dispersion ( fig 1C) where changes Δθ ≤ 2×10 -3 degrees are emphasized. When considering suspensions of larger cells ( R 1 ~ 0.5 mm), impedance

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Estimation of body composition and water data depends on the bioelectrical impedance device

.5 (-29 to -20) -19 1 FM (kg) 14±4 5±4.4 0.07* 0.27* 8.8+5.1 (81+202.4) 7.2 to 10 (15 to 147) -1.1 19 Normal weight subjects (n=120) Bland-Altman 95% limits of agreement Data analysed BIS SFBIA ICC r Bias a (%) b 95%CI Bias c (%) d Lower Upper R (ohm) 718±99 621±97 -0.02 -0.05 97+141 (14.6+20.6) 71 to 122 (11 to 18) -180 374 Xc (ohm) 82±9.6 63±8.9 0.04 0.13 19+12 (25.8+16.9) 16 to 21 (23 to 29) -5.3 43 PA ( ₒ ) 6.6±0.8 5

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Screening post-menopausal women for bone mineral level by bioelectrical impedance spectroscopy of dominant arm

/m 2 ) Normal 21 30.76 ± 5.51 [19.82, 43.57] NS NS Osteopenia 22 29.97 ± 6.02 [16.41, 43.42] - NS Osteoporosis 5 25.25 ± 1.33 [24.03, 27.33] - - Dominant arm Characteristic Frequency (kHz) Normal 21 51.72 ± 8.57 [39.92, 69.57] NS P < 0.005 Osteopenia 22 55.91 ± 10.01 [39.96, 75,68] - NS Osteoporosis 5 65.42 ± 12.96 [57.98, 88.30] - - Total Lumbar Spine BMD (g∙cm -2 ) Normal 21 1.048 ± 0.08 [0.934, 1.259] P < 0.001 P < 0.001 Osteopenia 22 0.855 ± 0.05 [0.784, 0

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Impedimetric characterization of human blood using three-electrode based ECIS devices

Design 1 Design 2 Design 3 Design 4 Data e % Data e % Data e % Data e % R S (Ω) 1353 1.83 1112 1.85 906.5 1.79 654.8 1.74 C S (Fs n-1 ) ×10 -9 46.12 4.98 55.13 5.01 66.43 4.81 90.19 4.64 (RΩ I ) 1588 3.01 1306 2.99 1060 2.81 767 2.67 Q M (Fs n-1 ) ×10 -9 5.05 3.16 6.14 3.16 7.52 3 10.36 2.87 n 0.92 0.03 0.92 0.03 0.92 0.03 0.92 0.03 χ 2 value 1.06×10 -3 1.06×10 -3 9.66×10 -4 8.96×10 -4 From the Table 2 , it is

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A single differential equation description of membrane properties underlying the action potential and the axon electric field

}^{0.5e}}\sin \pi t \right)}{{{\left( 0.5\pi \right)}^{\tanh \left( 4\pi \frac{\mu B}{kT} \right)}}\left( {{G}_{in}}\cosh \pi \text{X} \right)} - 67.9 \times 10^{-3}V}$$ Figure 1 is a plot of V m vs. t from (4b)† and demonstrates the classical action potential voltage cycle in nerve under stable equilibrium conditions [ 11 , 18 , 23 , 25 , 61 , 63 ]. VI Discussion A Inference of Ionic Current Flow In the classical Hodgkin-Huxley model, it’s well-known that the lipid bilayer of the axon membrane is modeled as a lumped-capacitance C m (F) [ 11

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Finite difference model of a four-electrode conductivity measurement system

{bnd}}}+{{\text C}_{6\text{bnd}}}) \\ \end{align}$$ Where C 1 bnd = C 6 * | z ctr − z bnd | ( x ctr − x bnd ) 2 + ( y ctr − y bnd ) 2 + ( z ctr − z br $${{\text C}_{1\text{bnd}}}={{\text C}_{6}}*\frac{\left| {{\text{z}}_{\text{ctr}}}-{{\text{z}}_{\text{bnd}}} \right|}{\sqrt{{{\left( {{\text{x}}_{\text{ctr}}}-{{\text{x}}_{\text{bnd}}} \right)}^{2}}+{{\left( {{\text{y}}_{\text{ctr}}}-{{\text{y}}_{\text{bnd}}} \right)}^{2}}+\text{(} {{\text{z}}_{\text{ctr}}}-{{\text{z}}_{\text{br}}} }}$$ So the discretization of Equation (10) is: (17) C 1 ϕ 1

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Investigating the quasi-oscillatory behavior of electrical parameters with the concentration of D-glucose in aqueous solution

different sets of volume fractions of glucose in DI water. Results and Discussion Fig. 3 (a) – (c) depicts the plots of variation of impedance, capacitance and conductance with volume fraction of glucose in the DI water-glucose solution for the frequencies 1 kHz, 10 kHz and 100 kHz. The experiment has been performed within the volume fraction range of 0.1 to 0.5. It is apparent from all such plots that the variation of electrical parameters of interest exhibits a quasi-oscillatory behavior with the volume fraction of glucose in the solution, instead of showing a

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