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We are used the set of two plane semitransparent mirrors with the dielectric covering for the generation of multi-beam interference gradient light field. Between mirrors the air wedge is located. The generation of twodimensional distribution of interference maximums is observed in the reflected field. The controlling by the spatial distribution of multi-beam interference light field is experimental investigated.

Finite element analysis (FEA) is an effective tool for the analysis of bioelectromagnetism. It has been successfully applied to various problems over other conventional methods such as boundary element analysis and finite difference analysis. However, its use has been limited due to overwhelming computational load despite of its analytical power. We have previously developed a novel mesh generation scheme that produces FE meshes that are content-adaptive to given images. These image content-adaptive FE meshes (cMeshes) represent the electrically conducting domain more effectively with less numbers of nodes and elements, thus lessen the computational load. However, their impacts on FEA have not been assessed yet. In this study, we evaluated the impact of cMeshes on FEA via comparing the forward solutions with various cMesh head models to the solutions from the reference FE head model in which fine and equidistant FEs constitute the model. Correlation coefficient (CC), relative error (RE), and computation time (CT) are used as performance indices. The results show that there is a significant gain in computation time with minor loss in numerical accuracy. We believe that cMeshes should be useful in the FEA of bioelectromagnetic problems.

Intracardiac electrical impedance was proposed as a method of assessing of signal for pacing control since 20 years. In cardiac pacing applications of impedance method one or more intracardiac pacing leads and active pacemaker housing are used as poles for measurement procedure. The stroke volume (SV) signal can be calculated from impedance signal by specialized algorithm in typical pacing system. Our previous study has showed that in group of 42 syncopic patients developing of vasodepresive reaction the SV drop was observed significantly before blood pressure (BP) drop. We have found that the SV drop is excellent indicator of early phase of syncope. In order to confirm that impedance cardiography and Penaz plethysmographic methods for assessment of SV provide the same results additional study were performed. The group of 6 patients were enrolled in the study group. All patients underwent standard passive head up tilt test (HUT). The standard HUT with 20 min. of elevation (60%) was followed by nitroglycerine (NTG) administration of 300 mg of NTG for patients with negative (no syncope) passive result. Impedance cardiography and Penaz plethysmography were carried out parallely during whole study. The statistical ANOVA analysis of the obtained data showed no significant differences of the results obtained in two applied methods. Study has showed that SV calculated from impedance signal should be taken under consideration for early syncope detection.

An electrode array sheet was produced and an electrocardiogram (ECG) mapping was performed. A plaster figure of a breast of a subject was prepared to form the silicone rubber sheet. 32 commercial ECG electrodes were arranged on the seat and the sheet was put on the breast of a subject to perform an electrocardiogram measurement. The electrocardiogram mapping measurement became simple by using this electrode array sheet.

We developed an experimental setup dedicated to study the behaviour of cardiac pacemakers exposed to low frequency interfering signal. The experimental setup allows to deduce the detection thresholds which induce pacemaker inhibition with conducted disturbances. The pacemaker housing and the lead wire of the electrode are implanted in a gel phantom. An interfering signal Vi, applied via two plane electrodes, induce a tension Veh located between the distal electrode and the housing of stimulator. Based on the admittance method, a computer model has been developed to obtain the transfer function between the induced signal Veh and the interfering signal Vi. The analyzing results for the interference voltages at the pacemaker’s terminals are used to predict the EMI level and the predicted results are compared with the previously reported experimental results. To facilitate the study of the disturbances produced by complex signals the identification of the transfer function is done by using the method of the output error. Results obtained by numerical simulation are in good agreement with experimental values.

An equation describing the change of an extracellular potential distribution around a nerve at the moment of action potential propagation is derived using a current source model. To verify the equation, an infinite two-dimensional electrolyte band is proposed and analyzed by the conformal mapping method. In addition, a unique experiment using a simulated nerve is carried out.

Human provocation studies that investigate the effects of Global System for Mobiles (GSM) communication systems on the brain have focused on RF exposure. We wish to further extend such study by investigating the effect of both RF and ELF magnetic field exposure, the latter being emitted by the GSM handset’s battery switching. The use of a commercial handset as an exposure source for such investigations is problematic and therefore a simulated exposure source, capable of producing both RF and ELF components of exposure, is desirable. As a first step in developing such a source, we have quantified and characterized the ELF radiation from several commercial handsets (the RF characteristics being already well understood). Here we present experimental results where, field distribution, and pulse waveform characteristics at ELF frequencies are measured. Finally, an equivalent source suitable for reproducing the ELF component of human exposure to GSM handset radiation is proposed.

In magnetoencephalography (MEG) source localization, simplex method is widely used because it is simple and does not need the derivatives of the function. However, the simplex method is very sensitive to the choice of initial points. Thus, in this paper, a method of choosing the good initial starting points is proposed. First, the brain is divided into several partitions and the value of center of each partition is evaluated. Then, the point which has the lowest value is determined to be the initial point. In addition, we estimate the calculation time and the accuracy of the source localization according to increasing the number of partitions.

It is difficult to compare studies regarding energy absorption in humans from various radiofrequency (RF) sources due to the contradictions and inconsistencies in RF dosimetry literature. Assumptions used in Specific Absorption Rate (SAR) studies have been insufficiently explored, particularly with regard to the effect of natural variation in the human population of potentially key parameters such as morphology, internal tissue and bone thicknesses and location, dielectric parameters of tissues and overall size. Due to the nature of available computational models based on either complex realistic models or the simple single tissue models this issue is not easily explored since the identified parameters are not easily varied within the models. To overcome this deficiency, we have proposed an alternative compromise model which includes a reduced set of tissues in a semi-homogeneous, simplified geometry for which the key parameters may be varied parametrically. We have reviewed some of the available data which we have used to populate the new model, and have begun to investigate which of these assumptions are appropriate; what approximation can be used in physical and computational modeling of humans for SAR calculations; and what tradeoffs can be made between accuracy and modeling requirements for practical considerations. Key issues being investigated are how SAR varies between children and adults, between males and females, and how to model SAR in the fetus of pregnant females. It is hoped that this study will produce a model and methods which allow for faster, more accurate and more efficient assessment of compliance with radiofrequency exposure limits. We have previously completed work on the effect of cranial thickness, and here we present initial results pertaining to the effects of skin thickness on SAR

The primary objective of this study was to develop a preamplifier and a wireless surface EMG of a noninvasive type. The limitations of the existing system include its large size and the necessity of a wire. Therefore, this study focused on the development of a preamplifier which includes three electrodes and a wireless EMG. The EMG described herein is comprised of a preamplifier including an electrode for the measurement of the EMG signal, a main amplifier for signal processing, an A/D converter, and a Bluetooth module for wireless communication. The developed EMG utilized a UART (Universal Asynchronous serial Receiver and Transmitter) and Bluetooth protocols for communication. The sampling frequency of this system is 1,024 Hz. The developed EMG signal has relatively favorable characteristics as compared with current commercially available EMG systems. In our power spectral density analysis, the EMG signal was distributed between approximately 70 Hz and 200 Hz, and between approximately 10 Hz and about 50 Hz.