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

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Li Gun ◽  
Du Ning ◽  
Zhang Liang
Keyword(s):  
Electromagnetic Fields ◽  
Biological Tissue ◽  
Volume Fraction ◽  
Biological Effects ◽  
Effective Permittivity ◽  
Theoretical Perspective ◽  
Critical Issue ◽  
Biological Tissues ◽  
Fat Liver ◽  
Lcr Meter

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.

Electrical Properties Measurement of Rat Blood in 10 kHz-10 MHz

2013 ◽  
Vol 774-776 ◽  
pp. 836-839
Author(s):  
Gun Li
Keyword(s):  
Electromagnetic Fields ◽  
Biological Effects ◽  
Low Frequency ◽  
Electromagnetic Property ◽  
Critical Issue ◽  
Dielectric Dispersion ◽  
Frequency Range ◽  
Electrical Parameters ◽  
Rat Blood ◽  
Lcr Meter

Electromagnetic property of biological tissue is a critical issue for studying the biological effects of electromagnetic fields. In order to investigate the electrical parameters of rat blood and dispersion spectrum within the low-frequency, dielectric and conductivity parameters of rat blood was measured via HP4275A Multi Frequency LCR Meter in low frequency range (10 kHz-10 MHz), dispersive characteristics of blood electrical parameters was defined within the low-frequency. Dielectric properties of the measurement were used to compare with the theory of Cole-Cole fitting, and the fitting result shows that the Cole-Cole theory can well reflect the dielectric dispersion characteristics of rat blood. These results can be used to studying further biological effects of different frequencies electromagnetic fields.

Monte Carlo Simulation of Photon Transport for Computing Fluence Rate in Biological Tissue

2018 ◽  
Vol 13 (10) ◽  
pp. 1505-1513
Author(s):  
S. O. Bazara ◽  
R. S. Alanazi ◽  
A. Laref
Keyword(s):  
Monte Carlo ◽  
Absorption Coefficient ◽  
Blood Vessels ◽  
Biological Tissue ◽  
Theoretical Perspective ◽  
Biological Tissues ◽  
Point Sources ◽  
Fluence Rate ◽  
Photon Transport ◽  
Collimated Beam

In this research, we applied the Monte Carlo method to simulate photon transport in a biological tissue, consisting of epidermal, dermis, and blood vessels. Particularly, we computed the fluence rate of the system at a wavelength of 400 nm using different beam sources, such as collimated beam, Gaussian beam, and isotropic point sources. In addition, the fluence rate is calculated within the collimated beam at different wavelengths between 300–1000 nm by considering the absorption coefficient (μa) for blood, dermis, and epidermis. For the collimated beam, the resulting fluence rate was found almost similar in the case of the epidermis and dermis at wavelengths between 600–1000 nm, whereas the blood vessels occur at a wavelength of 400 nm with a maximum absorption coefficient of blood (μa) of 3586 cm–1. The present study illustrated the ability of the penetration of light in biological tissues and the escaped light could provide the information about the components of the biological tissue. From the theoretical perspective, the comprehension of light-tissue interactions can support the field of biomedical optics.

scholarly journals Effects of a Wireless Charging System Built for An Electric Kick Scooter on Human Biological Tissue

2020 ◽  
Vol 17 (8) ◽  
pp. 2662
Author(s):  
Ibrahim Dergham ◽  
Yasser Alayli ◽  
Rodrigue Imad ◽  
Yskandar Hamam
Keyword(s):  
Electromagnetic Fields ◽  
Biological Tissue ◽  
Biological Tissues ◽  
Magnetic Flux Density ◽  
International Electrotechnical Commission ◽  
Body Parts ◽  
Wireless Charging ◽  
Electrical Field ◽  
Charging System ◽  
The Magnetic Field

In this paper, the authors present an evaluation of the electromagnetic fields generated by a static wireless charging system designed for an electric kick scooter on the human biological tissue. The guidelines on the exposure to the electromagnetic fields are previously specified. In this work, a model is designed under COMSOL multi-physics to study the effects of the magnetic field on two possible body parts of a person, which might be exposed to this field, namely the head and the hands is analysed. The magnetic flux density, the induced electrical field, the specific absorption rate, and the resulting increase of temperature of biological tissues are modelled and compared to the limits and guidelines prescribed in the regulation established to limit the exposure of people to electromagnetic fields. Furthermore, the used wireless charging system is modified to operate at higher frequencies to study its effect. The obtained results are below the guidelines and limits of exposure to the electromagnetic fields specified by the International Commission on Non-Ionizing Radiation Protection, European Commission, Institute of Electrical and Electronics Engineers and International Electrotechnical Commission.

Biological effects of low-intensity radiofrequency fields and risk assessment for biota

2020 ◽  
Vol 60 (9) ◽  
pp. 592-596
Author(s):  
Elena I. Sarapultseva ◽  
Darya V. Uskalova ◽  
Ksenya V. Ustenko
Keyword(s):  
Radio Frequency ◽  
Electromagnetic Radiation ◽  
Electromagnetic Fields ◽  
Negative Impact ◽  
Biological Effects ◽  
High Sensitivity ◽  
Communication Technologies ◽  
Natural Ecosystems ◽  
Low Intensity ◽  
Different Levels

Despite the fact that there are still conflicting opinions about the damage caused by modern wireless communication technologies, most scientists report on the negative biological effects of low-intensity radio frequency electromagnetic radiation at different levels of the organization of live nature. There is no doubt that there is a need not only for a sanitary and hygienic assessment of man-made electromagnetic effects on humans, but also for an environmental assessment for biota. The purpose of the study was to assess the potential environmental risk of electromagnetic impact in the centimeter range on natural ecosystems. The initial data were the authors' own results in the field of radiobiology of non-ionizing radiation, as well as published of other researchers. The article analyzes the biological effects of radio frequency electromagnetic fields detected in organisms of different systematic groups and levels of organization. The data on the non-thermal biological effects of electromagnetic fields indicate a high sensitivity of different species to this factor. The analyzed research results emphasize the need to take into account the features of non-thermal effects of electromagnetic radiation on biota, since these radiations can have a negative impact on different hierarchical levels in natural ecosystems.

SIMULATION OF SINGLE CHANNEL BIOLOGICAL TISSUE SPECTROSCOPY USING COMSOL MULTIPHYSICS

2015 ◽  
Vol 77 (28) ◽  
Author(s):  
Azmi Abou Basaif ◽  
Nashrul Fazli Mohd Nasir ◽  
Zulkarnay Zakaria ◽  
Ibrahim Balkhis ◽  
Shazwani Sarkawi ◽  
...  
Keyword(s):  
Magnetic Induction ◽  
Biological Tissue ◽  
Single Channel ◽  
Medical Condition ◽  
Biological Tissues ◽  
Comsol Multiphysics ◽  
Accurate Information ◽  
Tissue Properties ◽  
Biological Soft Tissue

The enhanced ability to detect accurate location and measure the depth of a   metal inside a biological tissue is very useful in the assessment of medical condition and treatment. This manuscript proposed a solution via the measurement of the tissue properties using magnetic induction spectroscopy (MIS) method to describe the characterization of biological soft tissue. The objective of this study is to explore the viability of locating embedded metal inside a biological tissue by measuring the differences the biological tissue electrical properties using principle of Magnetic Induction Spectroscopy (MIS). Simulation is done using COMSOL Multiphysics software for accurate information on the involved parameters for both metal and biological tissues. Simulation has confirmed that MIS capable of detecting and locate embedded metal inside a biological tissue.

scholarly journals Biological Effects of Atmospheric Fields and Radiation

2020 ◽  
Vol 8 (10S2) ◽  
pp. 38-40
Keyword(s):  
Electromagnetic Fields ◽  
Video Game ◽  
Biological Effects ◽  
Base Station ◽  
Microwave Oven ◽  
Line Radiation ◽  
Electrical Systems ◽  
Geomagnetic Fields ◽  
Mobile Phone Radiation ◽  
Harmful Effects

Our atmosphere is full of electromagnetic fields emitted from wireless communication transmitters. At the same time the bio-systems (including humans, animals & birds and vegetation as well) are complex electrical systems. Naturally therefore, they are likely to have interaction and to be affected in some way or the other. Research into this field started with the knowledge about pleasing presence of negative charges and unpleasant presence of positive charges around us, concentrating effects of static or pulsating fields. Also came the explanation (and experimental verification) of Hindu mythological effects of geomagnetic fields coupled with solar activity. The effects of power line radiation and radiation from video game TV sets, microwave oven and other domestic instruments like electric blankets also figured in the research. At last the fastest emerging mobile telephony overpowered all others. Though the results of researches into possible harmful effects of mobile phone radiation and those of radiation from base station towers remain inconclusive partly because of influencing pressure from manufacturing and service providing companies, some of the researchers conclusively assert the harmfulness of the radiation at some level of field intensity present near the tower or the handset relating it to the specific absorption ratio (SAR) value. Recent increased observation of infertility among young couples is also attributed by some researchers to the effect of radiation from mobile kept in pantaloons pockets which becomes near their genitals affecting sperm or ovum. This review explains all these researches into bio-effects of electromagnetic fields and concludes that there is certainly some possible harmfulness of radiation above some level of intensity of fields.

scholarly journals Impact of secondary particles on microdistribution of deposited dose in biological tissue in the presence of gold and gadolinium nanoparticles under photon beam irradiation

2019 ◽  
Vol 5 (2) ◽  
pp. 109-116
Author(s):  
Ivan A. Konobeev ◽  
Yurij A. Kurachenko ◽  
Igor’ N. Sheino
Keyword(s):  
Biological Tissue ◽  
Biological Tissues ◽  
Photon Beam ◽  
Additional Dose ◽  
Tissue Water ◽  
Secondary Particles ◽  
Photon Sources ◽  
Initial Spectrum ◽  
Photon Spectra ◽  
The Impact

It is experimentally proven that nanoparticles of high-Z materials can be used as radiosensitizers for photon beam therapy. In the authors’ opinion, data available as of today on the impact of secondary particles (electrons, photons and positrons generated in biological tissue by penetrating beam of primary photons) on the distribution of deposited dose during photon beam therapy in the presence of nanoparticles, are insufficient. Investigation of this impact constituted the main goal of this work. Two-stage simulation was performed using Geant4 platform. During the first stage a layer of biological tissue (water) was irradiated by monoenergetic photon sources with energies ranging from 10 keV to 6 MeV. As the result of this modeling spectra of electrons, photons and positrons were obtained at the depth of 5 cm. During the second stage the obtained photon spectra were used to irradiate gold, gadolinium and water nanoparticles. Radial distributions of energy deposited around nanoparticles were obtained as the result of this modeling. Radial DEF (Dose Enhancement Factor) values around nanoparticles of gold and gadolinium positioned in water at the depth of 5 cm were obtained after processing the collected data. Contributions from primary photons and secondary particles (electrons, photons and positrons generated in the layer of water with 5-cm thickness by the penetrating beam of primary photons) in the additional dose deposited around the nanoparticles were calculated as well. It was demonstrated that layer of biological tissue placed between the source of photons and nanoparticles considerably changes the initial spectrum of photons and this change is significant in the analysis of mechanism of radiosensitization of biological tissues by nanoparticles for all energies of photon sources (up to 6 MeV). It was established that interaction of electrons and positrons with nanoparticles does not lead to significant increase of additional dose in the vicinity of their surfaces and can be most likely excluded from consideration in the analysis of radiosensitization mechanism of nanoparticles.

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