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Paper presents results of computer modeling based study of underground cavity EM response. Spherical cavity’s EM response in soil is considered in wide frequency range and different values of soil electrical conductivity. The study is related to the detection abilities of anti-personnel plastic mines by EM exposure.

Electric conductivities are measured and reported for Agarose - salt solutions at magnetic Nano Particles (mNP) hyperthermia applicably frequencies between 50 kHz and 250 kHz.

Paper presents results of computer modeling based on The Method of Auxiliary Sources. It is considered cavity’s EM response in soil, in wide frequency range and different values of soil’s electrical conductivity. The research is related to studding of the detection abilities of anti-personnel plastic mines by EM exposure.

Magnetic nanoparticle hyperthermia therapy is a promising technology for cancer treatment. The technique involves delivering magnetic nanoparticles (MNPs) into tumors, then activating the MNPs using an alternating magnetic field (AMF). The AMF generating system produces not only a magnetic field, but also an electric field. The electric field penetrates normal tissue and induces eddy currents, which result in unwanted heating of normal tissues. The magnitude of the eddy current depends, in part, on the AMF source and the size of the tissue exposed to the field. The majority of in vivo MNP hyperthermia therapy studies have been performed in small animals, which, due to the spatial distribution of the AMF relative to the size of the animals, do not reveal the potential toxicity of eddy current heating in larger tissues. This limitation has posed a nontrivial challenge for researchers who have attempted to scale up from a small animal model to clinically relevant volumes of tissue. For example, the efficacy limiting nature of eddy current heating has been observed in a recent clinical trial, where patient discomfort was reported. Until now, much of the literature regarding increasing the efficacy of MNP hyperthermia therapy has focused on increasing MNP specific absorption rate or increasing the concentration of MNPs in the tumor; i.e. - improving efficacy at what is thought to be the maximum safe field strength and frequency. There has been a relative dearth of studies focused on decreasing the maximum temperature resulting from eddy current heating, to increase therapeutic ratio. This paper presents two simple and clinically applicable techniques for decreasing maximum temperature induced by eddy currents. Computational and experimental results are presented to understand the underlying physics of eddy currents induced in conducting, biological tissues and to leverage these insights for the mitigation of eddy current heating during MNP hyperthermia therapy. Phantom studies show that these techniques, termed the displacement and motion techniques, reduce maximum temperature due to eddy currents by 74% and 19% in simulation, and by 77% and 33% experimentally. Further study is required to optimize these methods for particular scenarios; however, these results suggest larger volumes of tissue could be treated, and/or higher field strengths and frequencies could be used to attain increased MNP heating, when these eddy current mitigation techniques are employed.

Recently, nano-particles (NP) hyperthermia emerged as one of the most promising technologies for the treatment of cancers at the cell level. Studies show that cancer cells accept and accumulate NP more preferable than normal cells [1]. We have shown in [1], that heat production mechanism for Dartmouth mNP cannot be hysteresis. In this paper, we present experimental SAR measurement for Dartmouth mNP and give simulation results taking in account viscous friction loss as the main mechanism of SAR production. We have modeled eddy current heat generation in phantom as well as in the realistic human model. Results show that the eddy current heat effect is the same order as in mNP, which exhibits necessity of mechanism for eddy currents minimization.

The goal of the present work was to explore the influence of commercially available cell phone irradiation on the single neuron excitability and memory processes. A Transverse Electromagnetic Cell (TEM Cell) was used to expose single neurons of mollusk to the electromagnetic field. Finite-Difference Time-Domain (FDTD) method was used for modeling the TEM Cell and the electromagnetic field interactions with living nerve ganglion and neurons. Neuron electrophysiology was investigated using standard microelectrode technique. The specific absorption rate (SAR) deposited into the single neuron was calculated to be 0.63 W/kg with a temperature increment of 0.1°C. After acute exposure, average firing threshold of the action potentials was not changed. However, the average latent period was significantly decreased. This indicates that together with latent period the threshold and the time of habituation might be altered during exposure. However, these alterations are transient and only latent period remains on the changed level.

The influence of specific absorption rate averaging schemes on the spatial correlation between mass-averaged specific absorption rate and radio-frequency-induced steady-state temperature-rise distributions in the “Visible Human” body model exposed to plane waves in the 30–800 MHz frequency range is investigated through finite-difference time-domain modeling. The averaged specific absorption rate is computed on the basis of the IEEE Std. C95.3-2002 specific absorption rate mass-averaging algorithm, employing 1-g and 10-g averaging tissue masses and several air-inclusion factors. The analysis reveals that the 10-g average specific absorption rate yields larger global correlation with the corresponding radio-frequency-induced temperature-rise distribution for the considered plane-wave exposures, while the dependence on the air-inclusion factor features a distinctive threshold behavior.

The aim of present work is to explore the influence of extremely low-frequency electromagnetic fields (8.34 and 217 Hz) utilized in cell phones on habituation of the mollusk single neuron to intracellular stimuli. The isolated nervous system of the mollusk Helix Pomatia was used in the experiments. Helmholtz coils were used to expose brain ganglia to the low-frequency electromagnetic fields. Peak values of the extremely low-frequency fields were between 1 and 6 mT. Neuron electrophysiology was investigated using a standard microelectrode technique. Exposure of the neuron to the low-frequency electromagnetic fields caused dehabituation to intracellular stimulus. The effect was proportional to the magnetic induction peak value. The observed dehabituation occurs by degradation of the signal to noise ratio and by alteration of the neuron's normal function.

Finite Difference Time Domain (FDTD) method is successfully applied and used in variety of problems in applied electrodynamics. In this paper we present FDTD method for heat equation for classical Fourier model as well as for Cattaneo and Chen-Tzou models in micro and nano scales. Cattaneo Bio-Heat Equation for 1D case is investigated.

Background: Imaging plays a crucial role in the identification, localization and grading of prostate carcinoma. However current imaging methods for the prostate cancer diagnosis are complicated and partially

During exposure to the cell phone electromagnetic field (EMF), some neurons in the brain at areas of peak specific absorption rate (SAR) absorb more electromagnetic energy than is permitted by existing guidelines. The goal of the present work was to investigate the influence of cell phone-like EMF signal on excitability and memory processes in single neurons. A Transverse Electromagnetic Cell (TEM Cell) was used to expose single neurons of mollusk to the EMF. Finite-Difference Time-Domain (FDTD) method was used for modeling the TEM Cell and the EMF interactions with living nerve ganglion and neurons. Neuron electrophysiology was investigated using standard microelectrode technique. SAR deposited into the single neuron was calculated to be 8.2 W/kg with a temperature increment of 1.21°C. After acute exposure, the threshold of firing of action potentials (AP) was significantly decreased (p ≈ 0.001). Time of habituation to stimulation with the intracellular current injection was increased (p ≈ 0.003). These results indicate that acute exposure to EMF at high SARs impairs the ability of neurons to store information.

Influence of the EMF MF on the single Action potentials parameters and neuron synaptic habituation was investigated. It is shown, that AP parameters exert reduction after applying of the ELF EMF. Neuron synaptic excitability is increased due to applying ELF EMF.

This paper attempts to investigate relationship between specific absorption rate (SAR) obtained for different averaging volumes, different averaging schemes and temperature increase based on correlation analysis of their distributions in the child head for the frac14-length dipole antenna radiation at 1800 MHz. Different averaging masses and several SAR averaging procedures are considered. The goal of this investigation is to derive the best SAR related metric that describes the thermal response of the exposed tissue.

Solution of inverse problem for Pear-Shaped Monopole Antenna (PSMA) for Personal Communication Systems (PCS) is proposed together with a user-friendly program package. Antennas with dielectric coatings are numerically and experimentally studied. The proposed antenna utilizes the advantages of the simple design to match antenna structure with feeding cable and free space. PSMA contains a pear-shaped metallic core covered by a thin dielectric layer. A special shape of metallic part provides matching with feeding cable and dielectric layer keeps antenna size small. Influence of Antenna radiated field on the user body is investigated. The Method of Auxiliary Sources (MAS) and Finite Difference Time Domain Method (FDTD) are used to study mentioned problems.

In this paper, results of numerical simulation performed for assessment of human expose by EM radiation are presented. Visible human-air force model (http://www.nlm.nih.gov/research/visible/visible_human.html ) is chosen as realistic human model. Program package based on FDTD method is applied to simulate EM processes. Numerical study of EM expose is performed at discrete frequencies ranging from 35 MHz up to 1 GHz in case of different conditions of plane EM waves incident. Results of calculations - specific absorption rate (SAR) averaged to 1 g and 10 g and its distributions are presented in cross-sections and discussed for particular tissues.

Personal wireless communication device are used in immediate vicinity of the body, producing high localized RP energy deposition. The motivation of this research is to investigate possible influence of the EM devices on the live organisms, which may result of local tissues overheating. The proprietary computer program package based on the finite-difference time-domain (FDTD) method for electromagnetic (EM) and thermal analysis of inhomogeneous, as well as method of auxiliary sources (MAS) for partially homogeneous problems was developed. Temperature rise in heterogeneous realistic head model (downscaled to child head size) exposed to mobile phone radiation at 835 MHz is studied. 12 pt. SAR and power absorption in different materials is investigated.

In this paper Software Program Package (SPP) for study of the wide class of the EM problems based on the Method of Auxiliary Sources (MAS) [1] solver is described. This SPP allows solving 3D diffraction and wave propagation problems, close to the real scenarios. This SPP based on MAS as mutually complementary together with FDTD solver will be implemented into FDTDLab [2].

Influence of EM radiation at 900 MHz on mollusk neuron placed in TEM cell is investigated. TEM cell model for 900 MHz after numerical study is manufactured and validated. Spatial absorption Rate and temperature rise is calculated using FDTD method. Performed series of experiments with experimental results are presented and discussed. Results of experimental investigation RF EMF influence on the neuron functional activity- habituation, which is regarded as simplest kind of learning are presented.

Imitating waveguide aperture (IWGA) source for FDTD modeling is introduced and studied. IWGA source's mathematical expression is sufficient approximation of the near field, radiated from the fiber waveguide, in the process of computer simulation of the EM phenomena in PhCs; it could be used as excited source expression by the fiber waveguide

Temperature rise evaluation in human body exposed to RF energy is becoming increasingly important topic related to the future development of the RF exposure safety standards. Therefore the validation of the existing methods like FDTD used in such complex multidisciplinary studies is very important. The accuracy of the FDTD solution of the bio-heat equation which is most often used in this type if studies have been analyzed based on the developed program package. The effect of stair case geometry representation in FDTD grid has been investigated by comparing the test case with analytical solution. In addition comparison was made with the published results. Preliminary data show that in case of constant temperature boundary conditions FDTD results slightly differ from the analytical solution during the transition state of the heat transfer process while there is a much better agreement in steady state regime. In case of convective boundary conditions the steady state temperature distribution at the convective boundary obtained by FDTD method also differ insignificantly from the FEM results reported in literature and temperature values inside the model are almost identical with that from FEM models. The results point to the conclusion that the error in FDTD simulations may be attributed to faster heat exchange which is due to the difference of surface area between the smooth and stair case boundaries of the modeled structures. These results are similar to those reported in T. Samaras et al. (2006). The impact on temperature inside the body far from the boundary is less than 1% while at the boundary is in the range of 4-7% for the models with 0.5 mm grid resolution and tissue like thermal properties

This paper presents an approach to estimate the main characteristics (specific absorption rate (SAR), total absorbed EM power and temperature rise) related to human exposure to EM energy. The assessment is done numerically using a proprietary software package, which is based on the finite difference time domain (FDTD) method and the method of auxiliary sources (MAS) (used here for partially homogeneous models). The general goal is to provide an efficient and sufficiently accurate method to assess human exposure to EM fields in a wide frequency range and for different types of exposure conditions: far field exposure (from cellular base stations) and near field exposure (from personal wireless communication devices). Dependence of exposure on different posture and EM field distribution inside the body is considered.

The RF power absorption and specific absorption rate (SAR) distribution in a simplified three layer head phantom is investigated using a recently developed computational suit for electromagnetic and thermal analysis of biological objects exposed to RF energy. The simulations are based on FDTD methodology which is implemented in the code. The program is suitable for parametric analysis based on various thermal properties of the tissues including blood perfusion to study their influence on temperature change and its distribution associated with RF exposure. Various SAR averaging volumes are considered to find the one that is best correlated with temperature change distribution. The computations are performed at frequencies from 0.3 GHz to 3 GHz.

The Brooks visible Human model downscaled to a 10 years old child size, exposed to a mobile Phone operating at 835 MHz is studied. Using a custom program, based on the Finite-Difference Time-Domain (FDTD) method, point SAR as well as 1g and lOg averaged SAR values are compared to the results obtained using a commercial FDTD program. Temperature rise in the child head model under analysis for 0.6W output power is investigated using the Bio Heat equation.

The thermal effects of a cellular phone electromagnetic (EM) field on the human head were studied by computer simulation. A structural heterogeneous realistic model of the human head was used. EM analysis was performed via the finite-difference time-domain (FDTD) method (Taflove, A. and Hagness, S.C., "Computational Electrodynamics: the finite difference time-domain method", Artech House, 2000). Specific absorption rate (SAR) was evaluated and further thermal effects were investigated using the bioheat (BH) equation (Bernardi, P. and Pisa, S., IEEE Trans. Microwave Theory Tech., vol.48, p.1118-26, 1998); the temperature field distribution and temperature rise were investigated for different frequencies, powers and exposure times. The results show that exposure time and environmental temperature must be two of the characteristic quantities in a safety standard.

We investigate thermal effects in the human head exposed to the electromagnetic (EM) radiation of a mobile antenna at 0.9 GHz frequency. Computer simulation of EM and thermal phenomena in the given problem was performed. The simulation code is based on the finite-difference time-domain (FDTD) method for Maxwell's equations (Taflove, A. and Hagness, S., "Computational Electrodynamics: the finite difference time-domain method", 2nd edition, Artech House, 2000) and bio heat equations (Bernardi, P. and Pisa, S., IEEE Trans. Microwave Theory Tech., vol.48, p.1118-26, 1998) for the EM and thermal problems respectively.