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Dielectrical properties of living epidermis and dermis in the frequency range from 1 kHz to 1 MHz

.00±0.13 20 15 - 76 US 20MHz B scanner [25] 1.02±0.21 17 16 - 50 Biopsy [26] 0.85±0.11 5 26 - 74 US 22 MHz B scanner [27] Mathematical Model We consider conservation of charge—ohmic and displacement currents—in the electrodes of the EIS probe and two layers—living epidermis and dermis—in the stripped skin as illustrated schematically in Fig. 1b and summarized in Appendix A. We further employ scaling arguments [ 10 ] to reduce the living epidermis and electrodes to boundary conditions, as illustrated in Fig. 1c , which yields a

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The effect of heart pulsatile on the measurement of artery bioimpedance

, the important parts in this study are the pressure forces (the pressure during systolic and diastolic) and viscous forces (the viscosity of the blood). Eq.5 is always solved together with the continuity equation eq.6 . However, Eq.5 represents the conservation of momentum, while the continuity equation ( Eq.6 ) represents the conservation of mass. Furthermore, Fig.5 (B) describes the distribution of blood pressure along the artery Eq. (2 , 3 , 4 ) [ 14 ]. Discussion The effect of inserting a pulse, which is an extension in the diameter of the artery

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Mechanistic multilayer model for non-invasive bioimpedance of intact skin

differing thicknesses and electrical properties, other factors come into play such as aging, skin moisture and variation of blood flow due to ambient conditions. Fig. 1 Schematic of skin layers. In our earlier work, we derived a mathematical model based on conservation of charge for EIS measurements of human skin [ 1 , 2 , 3 ] between 1 kHz and 1 MHz by grouping the skin layers into three layers: viz., stratum corneum (SC), viable skin (VS) and adipose tissue (AT). The model, which was calibrated and validated with experimental EIS measurements, was

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Design and simulation of microfluidic device for metabolite screening and quantitative monitoring of drug uptake in cancer cells

represents compound speed (m/s). The first part of the equation equals to zero when an in-compressible fluidic compound flows as a response for conservation of fluidic compound mass. Availability of a certain solution to the convection formula provided an exact initial concentration profile c0(r), and a steady speed u: c ( r , t ) = c 0 ( r − u t ) $$\begin{array}{} \displaystyle c({\rm r},t)=c_{\rm 0}({\rm r}-{\rm u}t) \end{array}$$ Mask design After deciding the final geometry and drawing its model in COMSOL, a photo mask is designed for the fabrication of

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Estimating electrical properties and the thickness of skin with electrical impedance spectroscopy: Mathematical analysis and measurements

temperature was maintained at 21.7 ±0.3 C. Mathematical model A mathematical model based on conservation of charge in both the time- and frequency-domain for an alternating, sinusoidal current in the rotation-symmetric gold-plated electrodes (EL) of the probe and the skin – stratum corneum (SC), viable skin (VS) and adipose tissue (AT) – in the vicinity of the probe was derived in our earlier work [ 8 ]. In short, the model can be expressed as follows in the frequency domain: (1a) ∇ ⋅ J =0, $$\nabla \cdot \mathbf{J}\text{=0,}$$ (1b) J = − ( σ

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Impedance cardiography: Pulsatile blood flow and the biophysical and electrodynamic basis for the stroke volume equations

Mohapatra SN, Hill DW. Origin of the impedance cardiogram. In: Mohapatra SN. Non-invasive cardiovascular monitoring by electrical impedance technique. London: Pitman Medical Limited.;1981. P. 41. Mohapatra SN Hill DW Origin of the impedance cardiogram Mohapatra SN Non-invasive cardiovascular monitoring by electrical impedance technique London Pitman Medical Limited 1981 41 51 Seitz WS, McIlroy MB. Interpretation of the HJ interval of the normal ballistocardiogram based on the principle of conservation of momentum and aortic ultrasonic Doppler

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Analysis of a Mechanistic Model for Non-invasive Bioimpedance of Intact Skin

-circuit constructs are the most common [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , ], where the electrical properties of the skin are estimated through a tissue-equivalent circuit comprising real and hypothetical electrical components. Mechanistic models based on the Maxwell equations and various degrees of resolution of the various skin layers have also been derived [ 11 , 12 , 13 , 14 , 15 , 16 ,]. The key advantage of the mechanistic models is that they are based on actual physical phenomena in the form of conservation equations, as opposed to theoretical

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