Dielectric relaxation of normothermic and hypothermic rat corneas

Marzec, E.; Sosnowski, Przemysław; Olszewski, Jan; Krauss, Hanna; Bahloul, K.; Samborski, Włodzimierz; Krawczyk-Wasielewska, Agnieszka

doi:10.1016/j.bioelechem.2014.08.023

Cited by 8 publications

(5 citation statements)

References 43 publications

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“…These experiments were carried out in the wet and dry states of the sample in the air atmosphere using the measuring chamber described in the previous article [13]. The wet and dry conditions concerned the same sample.…”

Section: Methodsmentioning

confidence: 99%

Influence of water and temperature on the electrical conductivity of the human nail

Marzec

Olszewski

2019

J Therm Anal Calorim

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The human toenail was measured in vitro in the alpha-dispersion region of the electric field and the temperature from 22 to 150°C. The values of dielectric properties are much higher in the wet nails than in those without water of the same temperature and frequency. The peak temperature of dielectric parameters near 100°C for wet nails is attributed to the water removal process. The dielectric spectra of the nail revealed high-frequency relaxation at 25 kHz irrespective of the water content in the tissue. Our dielectric studies of the nail plate enable deeper analysis of the matrix-keratin-water system, which can facilitate the assessment of the electrical conductivity of this tissue in the state of health and diseased.

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Section: Methodsmentioning

confidence: 99%

Influence of water and temperature on the electrical conductivity of the human nail

Marzec

Olszewski

2019

J Therm Anal Calorim

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“…Only this in-phase component contributes to power consumption or loss. The dielectric loss tangent is proportional to the dielectric loss [4][5][6][7][8][9][10][11][12][13]. In addition, the complex dielectric constant due to the parallel plate capacitor due to the difference in materials is described in the literature [14], the difference in the frequency characteristics of pure water and blood is described in [15], and the effects of weak microwave exposure are described in [16].…”

Section: Half-power Depthmentioning

confidence: 99%

System for Monitoring Avian Cardiac Output and Breathing Patterns Using Transmission-Type Microwaves

Nakajima¹,

Kuwahira²,

Hata³

2022

J Multimed Inf Syst

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We report the development of a non-contact monitoring device for avian cardiac output and breathing patterns based on the anterior thoracic air sac pressure that uses transmission-type microwaves (2,400−2,500 MHz, continuous wave). Since the phase waveform represents the dielectric constant change, the phase reflects −j/ωc and the dielectric constant change is related to blood flow. The magnitude waveform is reflected from the electronic resistance of tissues due to the expansion of the anterior thoracic air sac, which mainly consists of the thoracic wall. To confirm these waveforms, pigeons and chickens were used for testing. To validate the output waveforms of the developed transmission-type microwave device, data from esophageal catheters and pressure sensors in the anterior thoracic air sac, abdominal air sac, and intraoral cavity were obtained. The waveform for the esophageal catheter, where electrocardiogram electrodes and an angular velocity sensor were installed, correlates with cardiac output. A heart sound microphone was used to confirm the closing sound of the arterial and mitral valves. The experimental results confirm that a linear waveform synchronized with the cardiac blood flow and the anterior thoracic air sac pressure of birds was obtained using transmission-type microwaves. The proposed device, which can monitor cardiac output and respiratory patterns, may enable the early screening of cytokine storms caused by avian influenza viruses. Existing devices use Doppler radar in the 10 to 77 GHz band; these high frequencies are reflected by the chest wall and do not reach deep into body, making it impossible to monitor the blood flow inside the body.

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“…In order to clearly express the volume fraction, we transform (4), (5), and (6). Here, we concern volume fraction ; from the Bottcher-Bordewijk model (see (4)), we get…”

Section: Comparison Of Theory and Experimentsmentioning

confidence: 99%

“…It can be predicted that the effective permittivity of the material will be underestimated by using the simply tandem model (see (4)). The serial-parallel models (see (5) and (6)) will overestimate the predicted value. The main reason for the above phenomenon is that the tissues also have the characteristics of dielectric dispersion.…”

Section: Comparison Of Theory and Experimentsmentioning

confidence: 99%

“…Many techniques and principles of testing permittivity in biological tissue are similar to the traditional engineering materials. Capacitance of the tissue is measured first, and then permittivity can be calculated by the test results via relationship between the tissue morphology and the electromagnetic theory [4][5][6]. That is, the experimental study on permittivity of biological tissue is conducted via calculation from the test result (capacitance).…”

Section: Introductionmentioning

confidence: 99%

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Effective Permittivity of Biological Tissue: Comparison of Theoretical Model and Experiment

Ning

Zhang

2017

Mathematical Problems in Engineering

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Permittivity of biological tissue is a critical issue for studying the biological effects of electromagnetic fields. Many theories and experiments were performed to measure or explain the permittivity characteristics in biological tissue. In this paper, we investigate the permittivity parameter in biological tissues via theoretical and experimental analysis. Firstly, we analyze the permittivity characteristic in tissue by using theories on composite material. Secondly, typical biological tissues, such as blood, fat, liver, and brain, are measured by HP4275A Multi-Frequency LCR Meter within 10 kHz to 10 MHz. Thirdly, experimental results are compared with the Bottcher-Bordewijk model, the Skipetrov equation, and the Maxwell-Gannett theory. From the theoretical perspective, blood and fat are regarded as the composition of liver and brain because of the high permittivity in blood and the opposite in fat. Volume fraction of blood in liver and brain is analyzed theoretically, and the applicability and the limitation of the models are also discussed. These results benefit further study on local biological effects of electromagnetic fields.

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Dielectric relaxation of normothermic and hypothermic rat corneas

Cited by 8 publications

References 43 publications

Influence of water and temperature on the electrical conductivity of the human nail

Influence of water and temperature on the electrical conductivity of the human nail

System for Monitoring Avian Cardiac Output and Breathing Patterns Using Transmission-Type Microwaves

Effective Permittivity of Biological Tissue: Comparison of Theoretical Model and Experiment

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