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Tsai B, Xue H, Birgersson E, Ollmar S, Birgersson U. Dielectrical Properties of Living Epidermis and Dermis in the Frequency Range from 1 kHz to 1 MHz. J Electr Bioimpedance 2019; 10:14-23. [PMID: 33584878 PMCID: PMC7531215 DOI: 10.2478/joeb-2019-0003] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Indexed: 06/01/2023]
Abstract
We determine the in-vivo dielectric properties-resistivity and relative permittivity-of living epidermis and dermis of human skin soaked with a physiological saline solution for one minute between 1 kHz and 1 MHz. This is done by fitting approximate analytical solutions of a mechanistic model for the transport of charges in these layers to a training set comprising impedance measurements at two depth settings on stripped skin on the volar forearm of 24 young subjects. Here, the depth settings are obtained by varying the voltage at a second inject on the electrical-impedance-spectroscopy probe. The model and the dielectric properties are validated with a test set for a third depth setting with overall good agreement. In addition, the means and standard deviations of the thicknesses of living epidermis and dermis are estimated from a literature review as 61±7 μm and 1.0±0.2 mm respectively. Furthermore, extensions to resolve the skin layers in more detail are suggested.
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Affiliation(s)
- B. Tsai
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore, Singapore117585
| | - H. Xue
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore, Singapore117585
| | - E. Birgersson
- Department of Mechanical Engineering, National University of Singapore, 5 Engineering Drive 2, Singapore, Singapore117576
| | - S. Ollmar
- Department of Clinical Science, Intervention and Technology, Karolinska Institutet, SE-14186StockholmSweden
| | - U. Birgersson
- Department of Clinical Science, Intervention and Technology, Karolinska Institutet, SE-14186StockholmSweden
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Tsai B, Birgersson E, Birgersson U. Mechanistic Multilayer Model for Non-invasive Bioimpedance of Intact Skin. J Electr Bioimpedance 2018; 9:31-38. [PMID: 33584918 PMCID: PMC7852014 DOI: 10.2478/joeb-2018-0006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Indexed: 06/02/2023]
Abstract
An approximate semi-analytical solution based on a Hankel transform of a mechanistic model for electrical impedance spectroscopy (EIS) is derived for a non-invasive axisymmetric concentric probe with m electrodes measuring the response of n layers of human skin. We validate the semi-analytical solution for the case when the skin is treated as a three-layer entity - (i) stratum corneum, (ii) viable skin comprising living epidermis and dermis and (iii) adipose tissue - on the volar forearm in the frequency range 1 kHz to 1 MHz with experimental EIS measurements of 120 young subjects. Overall, we find good agreement for both the mean magnitude and phase of the impedance as well as the natural variability between subjects. Finally, the semi-analytical solution is verified with the full set of equations solved numerically: Good agreement is found for the point-wise potential distribution in the three skin layers.
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Affiliation(s)
- B. Tsai
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore, Singapore, 117585
| | - E. Birgersson
- Department of Mechanical Engineering, National University of Singapore, 5 Engineering Drive 2, Singapore, Singapore, 117576
| | - U. Birgersson
- Department of Clinical Science, Intervention and Technology, Karolinska Institutet, SE-14186, Stockholm, Sweden
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Massarczyk R, Schwengner R, Dönau F, Frauendorf S, Anders M, Bemmerer D, Beyer R, Bhatia C, Birgersson E, Butterling M, Elekes Z, Ferrari A, Gooden ME, Hannaske R, Junghans AR, Kempe M, Kelley JH, Kögler T, Matic A, Menzel ML, Müller S, Reinhardt TP, Röder M, Rusev G, Schilling KD, Schmidt K, Schramm G, Tonchev AP, Tornow W, Wagner A. Nuclear deformation and neutron excess as competing effects for dipole strength in the pygmy region. Phys Rev Lett 2014; 112:072501. [PMID: 24579591 DOI: 10.1103/physrevlett.112.072501] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Indexed: 06/03/2023]
Abstract
The electromagnetic dipole strength below the neutron-separation energy has been studied for the xenon isotopes with mass numbers A=124, 128, 132, and 134 in nuclear resonance fluorescence experiments using the γELBE bremsstrahlung facility at Helmholtz-Zentrum Dresden-Rossendorf and the HIγS facility at Triangle Universities Nuclear Laboratory Durham. The systematic study gained new information about the influence of the neutron excess as well as of nuclear deformation on the strength in the region of the pygmy dipole resonance. The results are compared with those obtained for the chain of molybdenum isotopes and with predictions of a random-phase approximation in a deformed basis. It turned out that the effect of nuclear deformation plays a minor role compared with the one caused by neutron excess. A global parametrization of the strength in terms of neutron and proton numbers allowed us to derive a formula capable of predicting the summed E1 strengths in the pygmy region for a wide mass range of nuclides.
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Affiliation(s)
- R Massarczyk
- Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany and Technische Universität Dresden, 01062 Dresden, Germany
| | - R Schwengner
- Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany
| | - F Dönau
- Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany
| | - S Frauendorf
- University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - M Anders
- Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany and Technische Universität Dresden, 01062 Dresden, Germany
| | - D Bemmerer
- Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany
| | - R Beyer
- Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany
| | - C Bhatia
- Duke University, Durham, North Carolina 27708, USA and Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708, USA
| | - E Birgersson
- Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany
| | - M Butterling
- Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany and Martin-Luther Universität Halle-Wittenberg, 06099 Halle, Germany
| | - Z Elekes
- Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany
| | - A Ferrari
- Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany
| | - M E Gooden
- Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708, USA and North Carolina State University, Raleigh, North Carolina 27695, USA
| | - R Hannaske
- Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany and Technische Universität Dresden, 01062 Dresden, Germany
| | - A R Junghans
- Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany
| | - M Kempe
- Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany and Technische Universität Dresden, 01062 Dresden, Germany
| | - J H Kelley
- Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708, USA and North Carolina State University, Raleigh, North Carolina 27695, USA
| | - T Kögler
- Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany and Technische Universität Dresden, 01062 Dresden, Germany
| | - A Matic
- Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany
| | - M L Menzel
- Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany
| | - S Müller
- Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany
| | - T P Reinhardt
- Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany and Technische Universität Dresden, 01062 Dresden, Germany
| | - M Röder
- Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany and Technische Universität Dresden, 01062 Dresden, Germany
| | - G Rusev
- Duke University, Durham, North Carolina 27708, USA and Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708, USA
| | - K D Schilling
- Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany and Technische Universität Dresden, 01062 Dresden, Germany
| | - K Schmidt
- Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany and Technische Universität Dresden, 01062 Dresden, Germany
| | - G Schramm
- Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany and Technische Universität Dresden, 01062 Dresden, Germany
| | - A P Tonchev
- Duke University, Durham, North Carolina 27708, USA and Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708, USA
| | - W Tornow
- Duke University, Durham, North Carolina 27708, USA and Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708, USA
| | - A Wagner
- Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany
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Ferrari A, Beyer R, Birgersson E, Claussner J, Grosse E, Hannaske R, Junghans A, Kempe M, Kögler T, Massarczyk R, Matič A, Schilling KD, Schramm G, Schwengner R, Wagner A, Weiss F, Yakorev D. Optimization aspects of the new nELBE photo-neutron source. EPJ Web of Conferences 2010. [DOI: 10.1051/epjconf/20100805002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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