scholarly journals Comparación entre la función de cole-cole y la función de Debye para modelar el tejido biológico

2019 ◽  
pp. 1-5
Author(s):  
Celia María Calderón-Ramón ◽  
Héctor Daniel López-Calderón ◽  
Jesús Enríque Escalante-Martínez ◽  
María Inés Cruz-Orduña
Keyword(s):  
Biological Tissue ◽  
Breast Tissue ◽  
Relaxation Times ◽  
Biological Tissues ◽  
Electromagnetic Signal ◽  
Frequency Range ◽  
Electrical Parameters ◽  
Debye Function ◽  
Advantages And Disadvantages ◽  
The Time Domain

The study of the biological tissue varies its behavior, in function of the frequency to which it is subjected. The functions of Cole-Cole, Debye and Lorentz are considered the most used to study the parameters of conductivity and permittivity of biological tissue such as: liver, stomach, gray matter, pancreas, blood, breast tissue to name a few. Depending on the frequency, there may be three different relaxation times. These depend on the nature and physical characteristics of the tissue and its effect in the presence of an electromagnetic signal. The Cole-Cole function is most appropriate when considering a study in the frequency domain, and the Debye function is established to perform the study in the time domain. It is of particular interest to make a comparison between the methods of Cole-Cole and Debye, to define the advantages and disadvantages of each of them. The Lorentz function is used for frequencies of the Tera-Hertz order. Comparative graphs are obtained between both for the biological tissues mentioned above. For each of them the electrical parameters are calculated in a frequency range between 100 Hz and 10 GHz.

scholarly journals Dosimetry of Various Human Bodies Exposed to Microwave Broadband Electromagnetic Pulses

2021 ◽  
Vol 9 ◽  
Author(s):  
Jerdvisanop Chakarothai ◽  
Kanako Wake ◽  
Katsumi Fujii
Keyword(s):  
Microwave Frequency ◽  
Biological Tissues ◽  
Ultra Wideband ◽  
Inverse Laplace Transform ◽  
Frequency Range ◽  
Reflection And Transmission ◽  
Electromagnetic Pulses ◽  
Prony Method ◽  
The Time Domain ◽  
Cole Model

In this paper, human exposures to ultra-wideband (UWB) electromagnetic (EM) pulses in the microwave region are assessed using a frequency-dependent FDTD scheme previously proposed by the authors. Complex permittivity functions of all biological tissues used in the numerical analyses are accurately expressed by the four-term Cole–Cole model. In our method, we apply the fast inverse Laplace transform to determine the time-domain impulse response, utilize the Prony method to find the Z-domain representation, and extract residues and poles for use in the FDTD formulation. Update equations for the electric field are then derived via the Z-transformation. Firstly, we perform reflection and transmission analyses of a multilayer composed of six different biological tissues and then confirm the validity of the proposed method by comparison with analytical results. Finally, numerical dosimetry of various human bodies exposed to EM pulses from the front in the microwave frequency range is performed, and the specific energy absorption is evaluated and compared with that prescribed in international guidelines.

scholarly journals Continuous-Wave THz Imaging for Biomedical Samples

2020 ◽  
Vol 11 (1) ◽  
pp. 71
Author(s):  
Yaya Zhang ◽  
Chuting Wang ◽  
Bingxin Huai ◽  
Shiyu Wang ◽  
Yating Zhang ◽  
...  
Keyword(s):  
Medical Imaging ◽  
Biomedical Imaging ◽  
Continuous Wave ◽  
Biological Tissues ◽  
Thz Spectroscopy ◽  
Label Free ◽  
Thz Imaging ◽  
Malignant Tumours ◽  
Advantages And Disadvantages ◽  
Imaging Application

In the past few decades, the applications of terahertz (THz) spectroscopy and imaging technology have seen significant developments in the fields of biology, medical diagnosis, food safety, and nondestructive testing. Label-free diagnosis of malignant tumours has been obtained and also achieved significant development in THz biomedical imaging. This review mainly presents the research status and prospects of several common continuous-wave (CW) THz medical imaging systems and applications of THz medical imaging in biological tissues. Here, we first introduce the properties of THz waves and how these properties play a role in biomedical imaging. Then, we analyse both the advantages and disadvantages of the CW THz imaging methods and the progress of these methods in THz biomedical imaging in recent ten years. Finally, we summarise the obstacles in the way of the application of THz bio-imaging application technology in clinical detection, which need to be investigated and overcome in the future.

A waveform inversion technique for measuring elastic wave attenuation in cylindrical bars

Geophysics ◽  
1992 ◽  
Vol 57 (6) ◽  
pp. 854-859 ◽  
Author(s):  
Xiao Ming Tang
Keyword(s):  
Elastic Wave ◽  
Wave Attenuation ◽  
Waveform Inversion ◽  
Finite Size ◽  
Low Frequency ◽  
Frequency Range ◽  
Multiple Reflections ◽  
Low Frequencies ◽  
The Time Domain ◽  
Attenuation Values

A new technique for measuring elastic wave attenuation in the frequency range of 10–150 kHz consists of measuring low‐frequency waveforms using two cylindrical bars of the same material but of different lengths. The attenuation is obtained through two steps. In the first, the waveform measured within the shorter bar is propagated to the length of the longer bar, and the distortion of the waveform due to the dispersion effect of the cylindrical waveguide is compensated. The second step is the inversion for the attenuation or Q of the bar material by minimizing the difference between the waveform propagated from the shorter bar and the waveform measured within the longer bar. The waveform inversion is performed in the time domain, and the waveforms can be appropriately truncated to avoid multiple reflections due to the finite size of the (shorter) sample, allowing attenuation to be measured at long wavelengths or low frequencies. The frequency range in which this technique operates fills the gap between the resonant bar measurement (∼10 kHz) and ultrasonic measurement (∼100–1000 kHz). By using the technique, attenuation values in a PVC (a highly attenuative) material and in Sierra White granite were measured in the frequency range of 40–140 kHz. The obtained attenuation values for the two materials are found to be reliable and consistent.

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.

Design and Analysis of Force Sensor for Condition Monitoring System of Ball Cold Heading Forming

2013 ◽  
Vol 364 ◽  
pp. 253-256 ◽  
Author(s):  
Qi Zhang ◽  
Ying Jun Li ◽  
Ru Jian Ma ◽  
Xiu Hua Men
Keyword(s):  
Condition Monitoring ◽  
Dynamic Performance ◽  
Force Sensor ◽  
Dynamic Measurement ◽  
Wide Frequency Range ◽  
Force Sensing ◽  
Frequency Range ◽  
Advantages And Disadvantages ◽  
Condition Monitoring System ◽  
Forming Defects

In order to solve the forming defects in the steel ball cold heading process, a novel force sensor which chooses the PVDF piezoelectric films as force-sensing elements is designed. The advantages and disadvantages of piezoelectric force sensor on measurement of the cold heading force are compared with existing force sensors. By using FEM, sensor’s linearity and the structure size are analyzed. Compared with the traditional sensor, this structure is more reasonable. The presented PVDF piezoelectric force sensor has wide frequency range, good dynamic performance, and can realize dynamic measurement.

scholarly journals Construction and calibration of TDR probes for volumetric water content estimation in a Distroferric Red Latosol

2013 ◽  
Vol 33 (5) ◽  
pp. 919-928 ◽  
Author(s):  
Rosimaldo Soncela ◽  
Silvio C. Sampaio ◽  
Marcio A. Vilas Boas ◽  
Maria H. F. Tavares ◽  
Adriana Smanhotto
Keyword(s):  
Water Content ◽  
Irrigation Management ◽  
Time Domain Reflectometry ◽  
Volumetric Water Content ◽  
Coefficient Of Determination ◽  
Calibration Model ◽  
Advantages And Disadvantages ◽  
Disturbed Soil ◽  
Red Latosol ◽  
The Time Domain

The determination of volumetric water content of soils is an important factor in irrigation management. Among the indirect methods for estimating, the time-domain reflectometry (TDR) technique has received a significant attention. Like any other technique, it has advantages and disadvantages, but its greatest disadvantage is the need of calibration and high cost of acquisition. The main goal of this study was to establish a calibration model for the TDR equipment, Trase System Model 6050X1, to estimate the volumetric water content in a Distroferric Red Latosol. The calibration was carried out in a laboratory with disturbed soil samples under study, packed in PVC columns of a volume of 0.0078m³. The TDR probes were handcrafted with three rods and 0.20m long. They were vertically installed in soil columns, with a total of five probes per column and sixteen columns. The weightings were carried out in a digital scale, while daily readings of dielectric constant were obtained in TDR equipment. The linear model θν = 0.0103 Ka + 0.1900 to estimate the studied volumetric water content showed an excellent coefficient of determination (0.93), enabling the use of probes in indirect estimation of soil moisture.

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.

Mathematical modeling of biological tissues electrical conductivity based on the ion electrodiffusion equations

2021 ◽  
Author(s):  
N.V. Kovalenko ◽  
K.V. Sovin ◽  
O.A. Ryabushkin
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
Electrical Properties ◽  
Biological Tissue ◽  
Physiological State ◽  
Biological Tissues ◽  
Radiation Heating ◽  
Tissue Degradation ◽  
Simulation Results ◽  
Electrical Properties Of Tissues

Problem formulating. The vital processes of biological tissues are closely related to their electrical properties. An important task is to create a physical and mathematical model that will link the electrical properties of tissues to their physiological state. Goal. Construction of a model of biological tissue electrical properties based on the equations of ion electrodiffusion. Result. The paper presents the model of biological tissue electrical properties based on the ion electrodiffusion equations, and compares the simulation results with the experimental results presented in the literature. Practical meaning. The presented model can be used to describe processes occurring in tissue at the level of concentration and conductivity of ions in individual cells and cell membranes. In particular, the process of tissue degradation during laser radiation heating can be described.

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