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4. Digitally Controllable Multifrequency Impedance Emulator for Bioimpedance Hardware Validation.

Author

Semenov, Dmitrii and Freeborn, Todd J.

Subjects
*ELECTRIC impedance, *TISSUES, *IMPEDANCE control, *ELECTRIC capacity, *ALGORITHMS
Abstract

ABSTRACT The accurate emulation of the electrical impedance of biological tissues is crucial for the development and validation of bioimpedance measurement devices and algorithms. This paper describes a digitally controllable impedance emulator capable of reproducing values representative of tissue bioimpedance in user‐specified resistance, reactance, and frequency ranges up to 1 MHz. The presented solution uses a 2R‐1C impedance model to emulate the impedance characteristics of a biological tissue. Specific selection of each element value in this model is achieved using analog multiplexers with low Ron$$ {R}_{on} $$ resistance. A MATLAB algorithm was developed for value estimation using target impedance requirements. An example design to emulate impedance from 1 kHz to 1 MHz with 10 Ω$$ \Omega $$ to 400 Ω$$ \Omega $$ resistance and −45Ω$$ -45\Omega $$ maximum reactance is provided. The nonideal behavior of this design was evaluated and compared against experimentally collected impedance measurements. Deviations of <1% were observed between experimental and theoretical resistances for values >50Ω$$ >50\Omega $$ up to 100 kHz (with approximately 5% deviations up to 1 MHz) and reactance deviations were also <1% up to 10 kHz. High frequency deviations are attributed to the parasitic capacitance in the realization of the design. The experimental results validate the design approach and realization for low frequencies. Overall, the innovation of the proposed approach is the control of both resistance and reactance for emulating electrical impedance representative of biological tissues. [ABSTRACT FROM AUTHOR]

Published
2024
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11. Fractional-Order Equivalent Circuit Representation of Kohlrabi Tissue Samples

Author

Van Fleet, Olivia, Conway, Lucy, Herencsár, Norbert, Freeborn, Todd, Van Fleet, Olivia, Conway, Lucy, Herencsár, Norbert, and Freeborn, Todd

Abstract

In an effort to investigate the electrical impedance properties of kohlrabi (Brassica oleracea var. gongylodes L.) plants, the range/variability of kohlrabi impedance from a collection of 16 similarly sized samples were explored. The impedance data was collected in a bipolar configuration interfacing copper wires into discs of sliced kohlrabi plants. An optimization algorithm was used to fit the collected data to a fractional-order equivalent circuit model. The model used to represent the approximated data consisted of a fractional-order capacitor in series with a parallel CPE-R. The electrical impedance of all samples represented by this model had less than 10% deviation in the band from 40 Hz to 1 MHz. Despite having similar dimensions and electrode configurations (material, insertion depth, spacing), there was a high variability (up to 70%) between fractional-order model parameters of the samples.

Published
2024

14. Contributors

Author

Akbar, Umer, primary, Akbari, Ali, additional, Alinia, Parastoo, additional, Amato, Francesco, additional, Amendola, Sara, additional, Balaban, Ertan, additional, Beach, Christopher, additional, Bertschi, Mattia, additional, Braun, Fabian, additional, Caldani, Laura, additional, Camera, Francesca, additional, Casson, Alexander J., additional, Cauwenberghs, Gert, additional, Cay, Gozde, additional, Chi, Yu M., additional, Constant, Nicholas, additional, Di Rienzo, Marco, additional, Ding, Xiaorong, additional, Diouf, Rassoul, additional, Farooq, Muhammad, additional, Fazio, Timothy, additional, Ferrario, Damien, additional, Fontana, Juan Manuel, additional, Freeborn, Todd J., additional, Genzoni, Elsa, additional, Ghasemzadeh, Hassan, additional, Ghovanloo, Maysam, additional, Ha, Sohmyung, additional, Harrer, Stefan, additional, Jafari, Roozbeh, additional, Jayaraman, Sundaresan, additional, Jiang, Yuqi, additional, Kassanos, Panagiotis, additional, Keshavarz, Meysam, additional, Kim, Chul, additional, Koh, Amanda, additional, Korhonen, Ilkka, additional, Kurita, Yuichi, additional, Kuroda, Tomohiro, additional, Lemay, Mathieu, additional, Leonhardt, Steffen, additional, Lüken, Markus, additional, Luo, Ningqi, additional, Mankodiya, Kunal, additional, Mansano, Andre L., additional, Marrocco, Gaetano, additional, Martins, Gustavo C., additional, Masuda, Atsuji, additional, Mercier, Patrick P., additional, Miozzi, Carolina, additional, Mirmomeni, Mahtab, additional, Mühlsteff, Jens, additional, Nappi, Simone, additional, Occhiuzzi, Cecilia, additional, Paradiso, Rita, additional, Parak, Jakub, additional, Park, Sungmee, additional, Petkov, Nicolai, additional, Piccirillo, Sara, additional, Poon, Carmen C.Y., additional, Proença, Martin, additional, Radeva, Petia, additional, Ravichandran, Vignesh, additional, Renevey, Philippe, additional, Rosa, Bruno Gil, additional, Sazonov, Edward, additional, Serdijn, Wouter A., additional, Sola, Josep, additional, Stoopman, Mark, additional, Takahashi, Hideya, additional, Talavera, Estefania, additional, Ulbrich, Mark, additional, Vikas, Vishesh, additional, von Cavallar, Stefan, additional, Wang, Hui, additional, Yang, Guang-Zhong, additional, Zhang, Yuan Ting, additional, and Zheng, Yali, additional

Published
2021
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17. Impact of head-down-tilt body position on abdomen resistance for urinary bladder monitory applications.

Author

Freeborn, Todd J., Critcher, Shelby, and Hooper, Gwendolyn L.

Subjects
POSTURE, ABDOMEN, YOUNG adults, ELECTRIC impedance, BODY fluids, BLADDER, TISSUES
Abstract

Tissue electrical impedance (or bioimpedance) is a quantity related to the passive, frequency-dependent electrical properties of a biological tissue and is a promising modality for continuous monitoring of relative bladder volume and bladder activity. In this study, the impact of body position [specifically 6° headdown tilt (HDT)] intended to induce fluid redistribution and, therefore, result in a change in the electrical resistance of the abdomen is evaluated. The abdomen resistance (10 kHz-100 kHz) of nine healthy young adults was measured before and after 240 min in a 6° HDT position. Over this period, the resistance increase was not statistically significant even though the average bladder volume increased by 506 mL. It was expected that the abdomen resistance would decrease with an increase in bladder volume over this period. The masking of the expected resistance decrease is attributed to the shift in the fluid from the legs/abdomen to the neck/chest caused by the HDT body position over this period. Overall, this suggests that methods to differentiate bladder volume changes from other types of fluid shifts in the body are needed for resistance-based monitoring under free-living conditions. [ABSTRACT FROM AUTHOR]

Published
2024
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30. Distinguishing Liquid Solutions With Alcohol Using Electrical Impedance Measurements: Preliminary Study for Food Safety Applications

Author

Slay, John, Šotner, Roman, Freeborn, Todd, Jeřábek, Jan, Polák, Ladislav, Petržela, Jiří, Vyplel, Vojtěch, Slay, John, Šotner, Roman, Freeborn, Todd, Jeřábek, Jan, Polák, Ladislav, Petržela, Jiří, and Vyplel, Vojtěch

Abstract

Methods for identifying contaminants in liquids (such as wine) typically require laboratory analyses of samples using precision equipment, which is expensive in terms of both time and required resources. Therefore, there is a need to identify alternative measurement approaches to reduce the cost in terms of equipment, personnel, and time. One sensing approach to characterize liquid properties and potentially identify contaminants is electrical impedance spectroscopy (EIS). In this work, the electrical impedance of 25-mL samples of three solutions with alcohol (plum distillate, isopropyl alcohol, and winter windshield solution) and a control sample of distilled water were measured using a Keysight 4294A. The liquids with alcohol content (plum distillate, isopropyl alcohol, and winter windshield solution) have lower impedance magnitude in the frequency band below 100 kHz, with specific values of 139, 76, and 7 k at 40 Hz, compared to the reference distilled water sample (approximately 315 k ). This suggests that solutions with alcohol (and other chemicals) have increased conductivity in comparison to the distilled water and that impedance may be a suitable approach to differentiate liquids with and without contaminants.

Published
2023

35. Contributors

Author

Abdel-Malek, Hany L., primary, AbdelAty, Amr M., additional, Abdelwahab, M.M., additional, Aboelela, Magdy A.S., additional, Al-Mekhlafi, S.M., additional, Attia, A.M., additional, Azar, Ahmad Taher, additional, Belkhatir, Zehor, additional, Biswas, Karabi, additional, Cattani, Carlo, additional, Dimeas, Ilias, additional, Duy, Vo Hoang, additional, Dvorak, Jan, additional, Ebid, Shaimaa E.K., additional, Elwakil, Ahmed S., additional, Elwy, Omar, additional, Freeborn, Todd J., additional, Gao, Feng, additional, Hamed, Esraa M., additional, Hennas, Rania Helmy Mansour, additional, Ibrahim, Ahmed M., additional, Jerabek, Jan, additional, Joshi, Vrunda, additional, Kamal, Nashwa A., additional, Kathuria, Tribhi, additional, Kler, Dhruv, additional, Koton, Jaroslav, additional, Kubanek, David, additional, Kumar, Vineet, additional, Laleg-Kirati, Taous Meriem, additional, Machado, J.A. Tenreiro, additional, Madian, A.H., additional, Madian, Ahmed H., additional, Mehta, Utkal, additional, Mohamed, Ahmed S.A., additional, Mohamed, N.A., additional, N’Doye, Ibrahima, additional, Ostalczyk, Piotr, additional, Pham, Viet-Thanh, additional, Psychalinos, Costas, additional, Radwan, Ahmed G., additional, Raj, Balwinder, additional, Rana, K.P.S., additional, Rashad, Somia H., additional, Said, Lobna A., additional, Sharma, Pallavi, additional, Soliman, Ahmed M., additional, Sweilam, N.H., additional, Thakar, Ujjwala, additional, Tolba, Mohammed F., additional, Vaidyanathan, Sundarapandian, additional, Vastarouchas, Costas, additional, Volos, Christos, additional, Vyawahare, Vishwesh A., additional, Wang, Xiong, additional, Yang, Xiao-Jun, additional, Yousri, D.A., additional, and Zahran, D.M., additional

Published
2018
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46. Flexible PCB Failures From Dynamic Activity and Their Impacts on Bioimpedance Measurements: A Wearable Case Study

Author

CRITCHER, SHELBY and FREEBORN, TODD J.

Subjects
trace cracking, Computer science, wearable sensors, bioimpedance, Hardware_INTEGRATEDCIRCUITS, Wearable computer, Flexible printed circuits, Electric apparatus and materials. Electric circuits. Electric networks, TK452-454.4, failure analysis, Article, Simulation
Abstract

Wearable health monitoring systems that collect data in free-living environments are becoming increasingly popular. Flexible printed circuits provide a commercially available option that can conform to the shape of a wearable system and support electronic sensing and flexible interconnect. However, repetitive dynamic activity can stress and damage the interconnect of flexible PCBs which degrades data quality. This case study evaluated the performance of flexible PCBs providing interconnect between electrodes and sensing electronics for tissue bioimpedance measurements in a wearable system. Resistance data (1 kHz to 128 kHz) was collected from localized knee tissues of 3 participants using the wearable design with flexible PCBs over 7 days of free-living. From electrical and optical inspection after use trace cracking of the flexible PCBs occurred, degrading tissue resistances reported by the wearable system. Exploration of these results advances understanding of how flexible PCBs perform in free-living conditions for wearable bioimpedance applications.

Published
2021

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