Accurate Multiscale Skin Model Suitable for Determining the Sensitivity and Specificity of Changes of Skin Components

Fröhlich, Jürg; Huclova, Sonja; Beyer, Christian; Erni, Daniel

doi:10.1201/b17205-17

Cited by 2 publications

(3 citation statements)

References 60 publications

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“…Another future step would be to simulate multicellular structures to determine the effects of different model details (e.g. the density of the ER) on the effective material properties of tissues in the context of multiscale modeling as developed in Froehlich et al [2014]. This would allow the determination of the EM energy intake at the microstructural level in cells and their organelles as part of a realistic exposure scenario.…”

Section: Discussionmentioning

confidence: 99%

“…Due to this setup, the (computational) unit cell is effectively periodically extended in each direction indicated by the PBC. This approach was used in the past to investigate the effective material parameters of randomized (bio‐)composites [Krakovsky and Myroshnychenko, 2002; Jerbic et al, 2020], and single cells [Huclova et al, 2010; Froehlich et al, 2014]. A description of how these simulations are verified by mixing rules is given in the Appendix.…”

Section: Methodsmentioning

confidence: 99%

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The Importance of Subcellular Structures to the Modeling of Biological Cells in the Context of Computational Bioelectromagnetics Simulations

Jerbic

Svejda

Sievert

et al. 2023

Bioelectromagnetics

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Numerical investigation of the interaction of electromagnetic fields with eukaryotic cells requires specifically adapted computer models. Virtual microdosimetry, used to investigate exposure, requires volumetric cell models, which are numerically challenging. For this reason, a method is presented here to determine the current and volumetric loss densities occurring in single cells and their distinct compartments in a spatially accurate manner as a first step toward multicellular models within the microstructure of tissue layers. To achieve this, 3D models of the electromagnetic exposure of generic eukaryotic cells of different shape (i.e. spherical and ellipsoidal) and internal complexity (i.e. different organelles) are performed in a virtual, finite element method-based capacitor experiment in the frequency range from 10 Hz to 100 GHz. In this context, the spectral response of the current and loss distribution within the cell compartments is investigated and any effects that occur are attributed either to the dispersive material properties of these compartments or to the geometric characteristics of the cell model investigated in each case. In these investigations, the cell is represented as an anisotropic body with an internal distributed membrane system of low conductivity that mimics the endoplasmic reticulum in a simplified manner. This will be used to determine which details of the cell interior need to be modeled, how the electric field and the current density will be distributed in this region, and where the electromagnetic energy is absorbed in the microstructure regarding electromagnetic microdosimetry. Results show that for 5 G frequencies, membranes make a significant contribution to the absorption losses. Bioelectromagnetics. 44:26-46, 2023.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

The Importance of Subcellular Structures to the Modeling of Biological Cells in the Context of Computational Bioelectromagnetics Simulations

Jerbic

Svejda

Sievert

et al. 2023

Bioelectromagnetics

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“…A more rigorous approach builds upon a hierarchically organized multiscale EM model that is rooted in the skin's proper cellular structure, in conjunction with a numerical homogenization procedure of the tissue's microstructure aiming at both the dispersive and tensorial EM material properties. Such multiscale approach has been pioneered by Huclova et al [13] for human tissue analysis up to 1GHz including the full skin layer morphology together with macroscopic textures like, e.g., the upper and deeper vessel plexus [14] arXiv:2007.00635v3 [physics.app-ph] 10 Aug 2020 to determine sensitivity and specificity of changes in skin components [15]. An extension to this model up to 1 THz has been provided by Saviz et al [16] using classical mixing formulas for the homogenization of the various tissue layers, and was later complemented by Spathmann et al [17] to include macroscopic features such as hair follicles and skin wrinkles for frequencies in the range of 100 GHz -10 THz.…”

Section: Introductionmentioning

confidence: 99%

Limits of Effective Material Properties in the Context of an Electromagnetic Tissue Model

et al. 2020

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Most calibration schemes for reflection-based tissue spectroscopy in the mm-wave/THzfrequency range are based on homogenized, frequency-dependent tissue models where macroscopic material parameters have either been determined by measurement or calculated using effective material theory. However, as the resolution of measurement at these frequencies captures the underlying microstructure of the tissue, we will investigate the validity limits of such effective material models over a wide frequency range (10 MHz -200 GHz). Embedded in a parameterizable virtual workbench, we implemented a numerical homogenization method using a hierarchical multiscale approach to capture both the dispersive and tensorial electromagnetic properties of the tissue, and determined at which frequency this homogenized model deviated from a full-wave electromagnetic reference model within the framework of a Monte-Carlo analysis. Simulations were carried out using a generic hypodermal tissue that emulated the morphology of the microstructure. Results showed that the validity limit occurred at surprisingly low frequencies and thus contradicted the traditional usage of homogenized tissue models. The reasons for this are explained in detail and thus it is shown how both the lower "allowed" and upper "forbidden" frequency ranges can be used for frequency-selective classification/identification of specific material and structural properties employing a supervised machine-learning approach. Using the implemented classifier, we developed a method to identify specific frequency bands in the forbidden frequency range to optimize the reliability of material classification.

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Accurate Multiscale Skin Model Suitable for Determining the Sensitivity and Specificity of Changes of Skin Components

Cited by 2 publications

References 60 publications

The Importance of Subcellular Structures to the Modeling of Biological Cells in the Context of Computational Bioelectromagnetics Simulations

The Importance of Subcellular Structures to the Modeling of Biological Cells in the Context of Computational Bioelectromagnetics Simulations

Limits of Effective Material Properties in the Context of an Electromagnetic Tissue Model

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