Michal Teplan - Academia.edu (original) (raw)
Papers by Michal Teplan
The aim of the simulation study was Introduction The inverse solution using two dipoles was sugge... more The aim of the simulation study was Introduction The inverse solution using two dipoles was suggested in [1] for localization of two simultaneous lesions which can occur in patients with ischemic heart disease and atherosclerosis. It was supposed that each lesion can be represented by one dipole. As it is known, such inverse solution is ill-posed [2] and the obtained resulting pair of dipoles may not be the proper representative of the location of the pair of lesions. The additional question in such a computation is whether we need the a priori information about the number of lesions or we are able to determine the number of lesions (one or two) from the properties of the obtained pair of dipoles. In this simulation study groups of inverse results were computed for each case. Then various characteristics of the resulting dipoles were specified and used as discriminating features enabling to recognize the correct inverse solutions representing the two lesions and to distinguish them ...
Computing in Cardiology 2013, 2013
The aim of the simulation study was to identify cases in which an inverse solution to two dipoles... more The aim of the simulation study was to identify cases in which an inverse solution to two dipoles characterizes the existence of two simultaneous lesions with changed repolarization. Difference STT integral body surface potential maps computed for 48 single lesions and 96 pairs of lesions were used as the input data for an inverse solution to two dipoles. Additional noise with signal to noise ratio (SNR) 20, 30 and 40dB was applied to the input data. The inverse solution was obtained as several pairs of dipoles. 23 characteristics of the solution were used as features for the quadratic variant of the Fisher discriminant analysis that should distinguish the inverse solutions that correctly identify 2 lesions from those yielding incorrect results or corresponding to a single lesion. The mean localization error in cases of correct results was 1.2±0.8cm regardless of the SNR. If eight most informative features were used, the sensitivity of the classification method was from 97 to 89% an...
2021 13th International Conference on Measurement, 2021
The development of innovative measurement approaches to investigate magnetic field (MF) biologica... more The development of innovative measurement approaches to investigate magnetic field (MF) biological effects is of great importance since we currently do not have any satisfying explanation of the MF biological interactions. The impedance spectroscopy is a well-known technique in the field of biological sample growth characterization. Here we present a proof of concept for cell culture impedance monitoring during the experiment with magnetic field exposure. We also emphasize the precise temperature monitoring has a key role in the exact interpretation of results since the minor temperature differences could lead to a substantial change in cell growth parameters.
2020 XXXIIIrd General Assembly and Scientific Symposium of the International Union of Radio Science, 2020
The application of pulsed electric field (PEF) is nowadays becoming a very promising tool for app... more The application of pulsed electric field (PEF) is nowadays becoming a very promising tool for application in medicine or food industry. However, the mechanisms of PEF interaction with living matter are still not fully elucidated. The aim of the presented work is to show the potential application of biological autoluminescence (BAL) for monitoring of pulsed electric field (PEF) biological effects on yeasts. The yeast cell culture (Saccharomyces cerevisiae) is exposed to the pulsed electric field (pulse duration: 0.1-5 ms, pulse number: 1-10, electric field strength: 3kV.cm−13 kV.cm^{-1}3kV.cm−1) and the BAL is monitored during exposure. The results indicate detectable differences in BAL dynamics when PEF is applied. Due to its noninvasive and label-free application, the BAL could be used as a beneficial tool for monitoring of PEF biological effects.
Intracranial pressure (ICP) belongs among relevant physiological parameters that are advised to b... more Intracranial pressure (ICP) belongs among relevant physiological parameters that are advised to be monitored at emergency units with patients after severe traumatic brain injury. However no advanced tools in a form of alarm based on ICP time series were developed. Procedure for assessment regarding actual degree of lethality is presented. ICP time segments and its derived features are applied into Gaussian mixture model in order to form vital and lethal clusters. From consecutive processing of time evolution of posterior probabilities a monitoring tool for each patient is built. New form of alarm may attract attention of medical stuff in order to adopt appropriate intervention for patients’ stabilization.
The aim of our research is a development of an automated experimental platform for identification... more The aim of our research is a development of an automated experimental platform for identification of the effects of weak low frequency (LF) electromagnetic field (EMF) on cells. The platform comprises multiple measurement stations, allowing monitoring and subsequent characterization of cell cultures. Main detection approaches include the methods of electroimpedance spectroscopy (EIS), optical microscopy, and turbidimetry. EIS provides information about cell culture growth and enables electrical characterization of cell structures. Morphology and cell kinetics are investigated via computer analysis of images obtained from video-microscopy. The complex measurement system allows efficient scanning of frequencies and amplitudes of EMF while searching for possible specific response of investigated biosystem. The developing platform aspires to contribute towards general methodology of investigation into LF EMF biological effects.
2019 12th International Conference on Measurement, 2019
It is known that the excessive oxidative processes (oxidative stress) in organisms are correlated... more It is known that the excessive oxidative processes (oxidative stress) in organisms are correlated with various diseases. Here we show the non-invasive monitoring of oxidative stress of yeast Saccharomyces cerevisiae cells using biological autoluminescence (BAL). The physical nature of this specific phenomenon is briefly introduced, and the results of BAL measurements from yeast cell solutions with the presence of hydrogen peroxide and ferrous ions are presented. The results confirm the assumption that the BAL intensity is mediated by hydroxyl radical, produced by the Fenton reaction, which causes oxidation of cells and initiates biochemical reactions leading to BAL generation. Since oxidative stress induced BAL from yeast cells has not been widely analyzed before in the literature, our results could be a useful contribution to this field of research.
Electromagnetic Biology and Medicine, 2009
Computer Methods and Programs in Biomedicine, 1998
The paper deals with the iterative three-dimensional (3D) smoothing of tomograms acquired by fast... more The paper deals with the iterative three-dimensional (3D) smoothing of tomograms acquired by fast Magnetic Resonance (MR) imaging methods. The smoothing method explored, which is aimed basically at the improvement of 3D visualization quality, uses the physical concept of geometry-driven diffusion with a variable conductance function, based on a specific measure of the 3D neighborhood homogeneity. A novel stopping criterion is proposed for iterative 3D diffusion processing. A study of the transition from 2D to 3D algorithms is carried out. The main structure of the program implementation of the smoothing algorithms developed is described. Three smoothing/filtering methods, aimed at the improvement of 3D visualization of MR tomograms of the brain, are quantitatively and visually compared using real 3D MR images. The results of computer simulations with 3D smoothing, segmentation and visualization are presented and discussed.
Machine Vision and …, 2009
Journal of Electrocardiology
Physiological Measurement
International Review of Automatic Control (IREACO), 2015
Computers in biology and medicine, 2015
The method for inverse localization and identification of two distinct simultaneous lesions with ... more The method for inverse localization and identification of two distinct simultaneous lesions with changed repolarization in the ventricular myocardium (two-vessel disease) is proposed and its robustness to errors in input data is tested in this simulation study. The inverse solution was obtained from the difference between STT integral body surface potential map computed with repolarization changes and the STT integral map from normal activation. In a numerical model of ventricles 48 cases of two simultaneous lesions and 48 cases of a single lesion were modeled. The effect of the lesions was taken to be represented by two dipoles. The input data were disturbed by three types of added noise. Twenty three characteristics of every obtained inverse solution were defined and four of them were used as the features in discriminant analysis task distinguishing the correct inverse solutions identifying two lesions. The mean localization error for identified two lesions was 1.1±0.7cm. The sens...
2010 3rd International Symposium on Applied Sciences in Biomedical and Communication Technologies (ISABEL 2010), 2010
Measurement Science Review, 2014
Short-lasting psycho-physiological relaxation was investigated through an analysis of its bipolar... more Short-lasting psycho-physiological relaxation was investigated through an analysis of its bipolar electroencephalographic (EEG) characteristics. In 8 subjects, 6-channel EEG data of 3-minute duration were recorded during 88 relaxation sessions. Time course of spectral EEG features was examined. Alpha powers were decreasing during resting conditions of 3-minute sessions in lying position with eyes closed. This was followed by a decrease of total power in centro-parietal cortex regions and an increase of beta power in fronto-central areas. Represented by EEG coherences the interhemispheric communication between the parieto-occipital regions was enhanced within a frequency range of 2-10 Hz. In order to discern between higher and lower levels of relaxation distinguished according to self-rated satisfaction, EEG features were assessed and discriminating parameters were identified. Successful relaxation was determined mainly by the presence of decreased delta-1 power across the cortex. Po...
2009 2nd International Symposium on Applied Sciences in Biomedical and Communication Technologies, 2009
The aim of the simulation study was Introduction The inverse solution using two dipoles was sugge... more The aim of the simulation study was Introduction The inverse solution using two dipoles was suggested in [1] for localization of two simultaneous lesions which can occur in patients with ischemic heart disease and atherosclerosis. It was supposed that each lesion can be represented by one dipole. As it is known, such inverse solution is ill-posed [2] and the obtained resulting pair of dipoles may not be the proper representative of the location of the pair of lesions. The additional question in such a computation is whether we need the a priori information about the number of lesions or we are able to determine the number of lesions (one or two) from the properties of the obtained pair of dipoles. In this simulation study groups of inverse results were computed for each case. Then various characteristics of the resulting dipoles were specified and used as discriminating features enabling to recognize the correct inverse solutions representing the two lesions and to distinguish them ...
Computing in Cardiology 2013, 2013
The aim of the simulation study was to identify cases in which an inverse solution to two dipoles... more The aim of the simulation study was to identify cases in which an inverse solution to two dipoles characterizes the existence of two simultaneous lesions with changed repolarization. Difference STT integral body surface potential maps computed for 48 single lesions and 96 pairs of lesions were used as the input data for an inverse solution to two dipoles. Additional noise with signal to noise ratio (SNR) 20, 30 and 40dB was applied to the input data. The inverse solution was obtained as several pairs of dipoles. 23 characteristics of the solution were used as features for the quadratic variant of the Fisher discriminant analysis that should distinguish the inverse solutions that correctly identify 2 lesions from those yielding incorrect results or corresponding to a single lesion. The mean localization error in cases of correct results was 1.2±0.8cm regardless of the SNR. If eight most informative features were used, the sensitivity of the classification method was from 97 to 89% an...
2021 13th International Conference on Measurement, 2021
The development of innovative measurement approaches to investigate magnetic field (MF) biologica... more The development of innovative measurement approaches to investigate magnetic field (MF) biological effects is of great importance since we currently do not have any satisfying explanation of the MF biological interactions. The impedance spectroscopy is a well-known technique in the field of biological sample growth characterization. Here we present a proof of concept for cell culture impedance monitoring during the experiment with magnetic field exposure. We also emphasize the precise temperature monitoring has a key role in the exact interpretation of results since the minor temperature differences could lead to a substantial change in cell growth parameters.
2020 XXXIIIrd General Assembly and Scientific Symposium of the International Union of Radio Science, 2020
The application of pulsed electric field (PEF) is nowadays becoming a very promising tool for app... more The application of pulsed electric field (PEF) is nowadays becoming a very promising tool for application in medicine or food industry. However, the mechanisms of PEF interaction with living matter are still not fully elucidated. The aim of the presented work is to show the potential application of biological autoluminescence (BAL) for monitoring of pulsed electric field (PEF) biological effects on yeasts. The yeast cell culture (Saccharomyces cerevisiae) is exposed to the pulsed electric field (pulse duration: 0.1-5 ms, pulse number: 1-10, electric field strength: 3kV.cm−13 kV.cm^{-1}3kV.cm−1) and the BAL is monitored during exposure. The results indicate detectable differences in BAL dynamics when PEF is applied. Due to its noninvasive and label-free application, the BAL could be used as a beneficial tool for monitoring of PEF biological effects.
Intracranial pressure (ICP) belongs among relevant physiological parameters that are advised to b... more Intracranial pressure (ICP) belongs among relevant physiological parameters that are advised to be monitored at emergency units with patients after severe traumatic brain injury. However no advanced tools in a form of alarm based on ICP time series were developed. Procedure for assessment regarding actual degree of lethality is presented. ICP time segments and its derived features are applied into Gaussian mixture model in order to form vital and lethal clusters. From consecutive processing of time evolution of posterior probabilities a monitoring tool for each patient is built. New form of alarm may attract attention of medical stuff in order to adopt appropriate intervention for patients’ stabilization.
The aim of our research is a development of an automated experimental platform for identification... more The aim of our research is a development of an automated experimental platform for identification of the effects of weak low frequency (LF) electromagnetic field (EMF) on cells. The platform comprises multiple measurement stations, allowing monitoring and subsequent characterization of cell cultures. Main detection approaches include the methods of electroimpedance spectroscopy (EIS), optical microscopy, and turbidimetry. EIS provides information about cell culture growth and enables electrical characterization of cell structures. Morphology and cell kinetics are investigated via computer analysis of images obtained from video-microscopy. The complex measurement system allows efficient scanning of frequencies and amplitudes of EMF while searching for possible specific response of investigated biosystem. The developing platform aspires to contribute towards general methodology of investigation into LF EMF biological effects.
2019 12th International Conference on Measurement, 2019
It is known that the excessive oxidative processes (oxidative stress) in organisms are correlated... more It is known that the excessive oxidative processes (oxidative stress) in organisms are correlated with various diseases. Here we show the non-invasive monitoring of oxidative stress of yeast Saccharomyces cerevisiae cells using biological autoluminescence (BAL). The physical nature of this specific phenomenon is briefly introduced, and the results of BAL measurements from yeast cell solutions with the presence of hydrogen peroxide and ferrous ions are presented. The results confirm the assumption that the BAL intensity is mediated by hydroxyl radical, produced by the Fenton reaction, which causes oxidation of cells and initiates biochemical reactions leading to BAL generation. Since oxidative stress induced BAL from yeast cells has not been widely analyzed before in the literature, our results could be a useful contribution to this field of research.
Electromagnetic Biology and Medicine, 2009
Computer Methods and Programs in Biomedicine, 1998
The paper deals with the iterative three-dimensional (3D) smoothing of tomograms acquired by fast... more The paper deals with the iterative three-dimensional (3D) smoothing of tomograms acquired by fast Magnetic Resonance (MR) imaging methods. The smoothing method explored, which is aimed basically at the improvement of 3D visualization quality, uses the physical concept of geometry-driven diffusion with a variable conductance function, based on a specific measure of the 3D neighborhood homogeneity. A novel stopping criterion is proposed for iterative 3D diffusion processing. A study of the transition from 2D to 3D algorithms is carried out. The main structure of the program implementation of the smoothing algorithms developed is described. Three smoothing/filtering methods, aimed at the improvement of 3D visualization of MR tomograms of the brain, are quantitatively and visually compared using real 3D MR images. The results of computer simulations with 3D smoothing, segmentation and visualization are presented and discussed.
Machine Vision and …, 2009
Journal of Electrocardiology
Physiological Measurement
International Review of Automatic Control (IREACO), 2015
Computers in biology and medicine, 2015
The method for inverse localization and identification of two distinct simultaneous lesions with ... more The method for inverse localization and identification of two distinct simultaneous lesions with changed repolarization in the ventricular myocardium (two-vessel disease) is proposed and its robustness to errors in input data is tested in this simulation study. The inverse solution was obtained from the difference between STT integral body surface potential map computed with repolarization changes and the STT integral map from normal activation. In a numerical model of ventricles 48 cases of two simultaneous lesions and 48 cases of a single lesion were modeled. The effect of the lesions was taken to be represented by two dipoles. The input data were disturbed by three types of added noise. Twenty three characteristics of every obtained inverse solution were defined and four of them were used as the features in discriminant analysis task distinguishing the correct inverse solutions identifying two lesions. The mean localization error for identified two lesions was 1.1±0.7cm. The sens...
2010 3rd International Symposium on Applied Sciences in Biomedical and Communication Technologies (ISABEL 2010), 2010
Measurement Science Review, 2014
Short-lasting psycho-physiological relaxation was investigated through an analysis of its bipolar... more Short-lasting psycho-physiological relaxation was investigated through an analysis of its bipolar electroencephalographic (EEG) characteristics. In 8 subjects, 6-channel EEG data of 3-minute duration were recorded during 88 relaxation sessions. Time course of spectral EEG features was examined. Alpha powers were decreasing during resting conditions of 3-minute sessions in lying position with eyes closed. This was followed by a decrease of total power in centro-parietal cortex regions and an increase of beta power in fronto-central areas. Represented by EEG coherences the interhemispheric communication between the parieto-occipital regions was enhanced within a frequency range of 2-10 Hz. In order to discern between higher and lower levels of relaxation distinguished according to self-rated satisfaction, EEG features were assessed and discriminating parameters were identified. Successful relaxation was determined mainly by the presence of decreased delta-1 power across the cortex. Po...
2009 2nd International Symposium on Applied Sciences in Biomedical and Communication Technologies, 2009