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Transient bioimpedance monitoring of mechanotransduction in artificial tissue during indentation

and contains the inlet and outlet holes and the microchannels through which S-DMEM (Dulbecco’s Modified Eagle’s Medium (DMEM) supplemented with 10 % (v/v) foetal bovine serum (FBS, PAA, Germany)) flows, which nourishes and so maintains the viability of the artificial skin. The microchannels also incorporate a 20x20 mm section which encloses an array of 50 μm diameter micropillars (see Fig. 2 ) which support a polycarbonate nanoporous membrane permitting the medium to diffuse through to the skin whilst also providing a platform to support the impedance sensor. The

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Testing miniaturized electrodes for impedance measurements within the β-dispersion – a practical approach

predominantly flow around the cells [ 31 , 32 , 33 ]. Only at higher frequencies (f > 1 MHz), when the membranes are electrically shortened, the impedance decreases due to the accessibility of the cytoplasm as current path which yields the β-dispersion. The impedance at low frequencies gives information about the cell volume fraction since isolating cell membranes decrease the current path. This however, needs either calibration with known cell densities or the knowledge of the conductivity of the extracellular electrolytes as well as the electrode geometry. More advanced

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Optically isolated current source

follows: The light emitting diode (LED) produces light that falls on two closely matched photodiodes, PD 1 and PD 2 . This causes current to flow in the reverse direction in the photodiodes. The current gain from the LED to photodiode PD 1 is K 1 and the current gain from the LED to photodiode PD 2 is K 2 . The ratio between the two current gains is K 3 = K 2 K 1 . ${{K}_{3}}=\frac{{{K}_{2}}}{{{K}_{1}}}.$ The factor K 3 will vary between different optocouplers, but a sorting is done by the manufacturers

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Geometric parameters optimization of planar interdigitated electrodes for bioimpedance spectroscopy

total impedance corresponds to the double layer capacitance and solution resistance in series. Total impedance becomes essentially resistive at frequencies lower than F Low , and C DL it contributes mainly to the total impedance value (6) Z ≈ 2 + jω ⋅ CDL ⋅ RSol j ⋅ ω ⋅ CDL $$\text{Z}\approx \frac{2+\text{j }\!\!\omega\!\!\text{ }\cdot \text{CDL}\cdot \text{RSol}}{\text{j}\cdot \text{ }\!\!\omega\!\!\text{ }\cdot \text{CDL}}$$ (7) FLow ≈ 1 π ⋅ RSol ⋅ CDL $$\text{FLow}\approx \frac{1}{\pi \cdot \text{RSol}\cdot \text{CDL}}$$ At lower

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Spatial resolution in electrical impedance tomography: A topical review

to lose their local character of measurements. They also found out that it can still be used for monitoring average features of spatially homogenous flows. However, this alternative cannot be used for non-homogenous flows because the measuring volumes should be as narrow as possible to get accurate information. It is difficult to have countermeasures for this effect because there has not yet been actual studies of the cause of the fringe effect over distances between dispersed non-conductive objects and the measuring plane. ii) The topography of the field

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Diagnosis of mitral insufficiency using impedance cardiography technique ICG

flow from the left ventricle into the left atrium [ 23 ]. MI is the most-frequent valvular heart disease in the world and it is constituted as the second most prevalent valve disease after aortic valve stenosis. The major complication of MI is heart failure, pulmonary hypertension, atrial fibrillation, and death [ 24 ]. There are several diagnostic tools in assessing Mitral Insufficiency such as the chest X-ray, the echocardiography, and catheterization. The most interesting diagnostic technique that can provide important information about MI is echo

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Cole Parameter Estimation from the Modulus of the Electrical Bioimpeadance for Assessment of Body Composition. A Full Spectroscopy Approach

the volunteers. The body parameters of the volunteers can be observed in Table I . Subject 5 is female and all the others are male. Table I Subjects body features Subjects Features Age (years) Height (cm) Weight (kg) Subject 1 32 176 99.0 Subject 2 30 165 60.0 Subject 3 26 174 94.4 Subject 4 26 182 83.8 Subject 5 24 175 72.5 D EBI Data Analysis and Comparison As the work flow on Fig. 1 indicates, the Cole curve fitting and BCA parameters estimation were performed on a total of 500

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Analysis of impedance measurements of a suspension of microcapsules using a variable length impedance measurement cell

parallel describe the current flow in the liquid surrounding the capsules. This model is very similar to the model in Figure 7 obtained by starting from a simple parallel connection of a resistor and a capacitor. A comparison of the measured impedance and the impedance predicted from the model from Figure 8 is shown in Figure 9 . Fig. 7 The final model that modeled suspension impedance with smallest fitting error. By fitting the measured data, the electrical parameters of the elements can be obtained. Table 1 presents fitted electrical parameters for

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Assessment of body composition in oncologic patients: Experimental survey on the role of bioimpedentiometric analysis

slightly apart and upper limb away from the body. The device generates a low intensity alternate current, which flows into the patient’s body. Final data are expressed in kilograms and in percent of total body weight. Impedentiometric data were collected from the instrument BIA 101 (Akern Bioresearch srl, Italy), and processed by the related software BIVA SOFTWARE 2002. BIA allows the assessment of body composition, defining total body water (TBW), intracellular water (ICW), extracellular water (ECW), fat free mass (FFM), body cell mass (BCM), fat mass (FM). Using

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Compression-dependency of soft tissue bioimpedance for in-vivo and in-vitro tissue testing

in lower frequencies, current flows between the cells and through the extracellular space, therefore the resistance measured at lower frequencies is mostly an indicator of the extracellular resistance. While at higher frequencies permeability of the cells’ membrane increases, which allows current to cross the cell membrane, and therefore both intracellular and extracellular resistances of tissue influence the measured resistance. The Cole model of biological tissue also supports this idea by the fact that open circuit occurs at lower frequencies at branches

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