It is very important to assess the skin condition for medical or cosmetical reasons. Bioimpedance... more It is very important to assess the skin condition for medical or cosmetical reasons. Bioimpedance Spectroscopy studies the frequency dependence of the electrical impedance of the biological material; the most interesting application would be the skin cancer detection. We studied electrical characteristics of the human skin, RS (series resistance), RP (parallel resistance) and C (capacitance), measuring with electrical impulses. The signal consists of electrical current impulses (width T' = 0.05÷10 ms, the “ON” period) followed by a pause (width T'' = 1÷100 ms, the “OFF” period) when the electrodes cannot receive or transmit current (high impedance status). The potential difference and the current between electrodes are displayed with the oscilloscope. The method allows measuring the characteristics of the skin in a more direct and explicit fashion, and it makes possible to discriminate more phenomena occurring into the skin. The Maxwell-Wagner effect, an interfacial rela...
Electrical methods for the assessment of materials are gaining interest because of their ease of ... more Electrical methods for the assessment of materials are gaining interest because of their ease of implementation. This paper presents some electrical techniques for cement and concrete characterization. For example, electrical resistivity of cement is correlated with its compressive strength and can be used to monitor the real-time evolution of cracking concrete. Archie's laws, which link the electrical conductivity to the material's porosity and to the structure of this porosity (tortuosity) can, estimate the ideal mix of concrete for a specific service life and environmental class. Electrical conductivity measurements can predict the fluid permeability through a porous material (Katz-Thompson formula) and this leads to a better design of pervious concretes for the maximization of water transport. Electrical measurements offer relevant information and versatility, and this makes them ideal for quality control, for designing and assessing construction and building materials.
ABSTRACT In this position paper we present our view of how water is distributed inside the skin&a... more ABSTRACT In this position paper we present our view of how water is distributed inside the skin's stratum corneum to create its electrical properties. The existence of a finite electrical resistance of the skin, especially for direct current, implies a continuous domain of water from the surface of the skin to the inner of the body. We propose water as a third compartment in stratum corneum that interpenetrates the other two compartments: intercellular lipids and corneocytes. We suppose that water exchange between the two generally accepted compartments, intercellular lipids and corneocytes, takes place at the junction between corneodesmosomes and lamellar extracellular lipids. We present the evidences from scientific literature sustaining such a view for water distribution in stratum corneum. This assumption could explain some electrical properties of the skin and why skin's permeability to hydrophilic solutes is better predicted by models that imply a substance transport through corneocytes and lipid bilayers in series.
IET Irish Signals and Systems Conference (ISSC 2008), 2008
Abstract The skin electrical properties are identified using a standard neuromuscular electrical ... more Abstract The skin electrical properties are identified using a standard neuromuscular electrical stimulation voltage pulse. The three component series equivalent electrical model was chosen to account for the skin electrical properties. A mathematical model for the ...
ABSTRACT Using a Nernst-Planck model, we show that the current density in a membrane's po... more ABSTRACT Using a Nernst-Planck model, we show that the current density in a membrane's pore as a function of voltage has three types of behavior: a quasi-ohmic behavior at low voltages, with a small slope, a non-ohmic linear dependence at large voltages, with a large slope, and a nonlinear transition region at intermediate voltages. The magnitude of the quasi-ohmic current from low voltages depends mainly on the height of energy barrier inside the pore, w, through an exponential term, ew. The low voltages domain is experimentally accessible and almost unexplored, despite the fact that it can offer direct information about the energy barrier inside a pore. The model has only two assumed parameters, the energy barrier height, w, and the relative size of the entrance region of the pore, r, with a clear physical meaning, an important advantage for fitting and interpreting experimental data. This simple model for the current-voltage nonlinearity is a good starting point for explaining the electrical behavior of the skin at low voltages. IFMBE Proceedings, 2011, Volume 36, Part 2, 156-159, DOI: 10.1007/978-3-642-22586-4_33 http://www.springerlink.com/content/q6332305485k48u2/
ABSTRACT We have studied the electrical time constants of human skin potential in response to a c... more ABSTRACT We have studied the electrical time constants of human skin potential in response to a constant current impulse (0.4-16 mA/100 us). Three relaxation times were found with values in the range 10-40 us, 100-200 us and 1-4 ms. By correlating the time constants with the electrical model of the skin we found that stratum corneum has a nonlinear resistance that diminishes and a nonlinear capacitance that increases with increasing values of current. IFMBE Proceedings, 2011, Volume 36, Part 2, 160-163, DOI: 10.1007/978-3-642-22586-4_34 http://www.springerlink.com/content/w7573u5j7513j332/
In this paper we present how the main parameters of an optimal velocity model, the velocity adapt... more In this paper we present how the main parameters of an optimal velocity model, the velocity adaptation time, τ, and the desired time gap between consecutive vehicles (time headway), T, control the structure of vehicular traffic flow. We show that the ratio between the desired time gap and the velocity adaptation time, T /τ, establishes the pattern formation in congested traffic flow. This ratio controls both the collective behavior and the individual response of vehicles in traffic. We also introduced a response (transfer) function, which shows how perturbation is transmitted between adjacent vehicles and permits the study of collective stability of traffic flow.
A model for current-voltage nonlinearity and asymmetry is a good starting point for explaining th... more A model for current-voltage nonlinearity and asymmetry is a good starting point for explaining the electrical behavior of nanopores in synthetic or biological membranes. Using a Nernst-Planck model, we found three behaviors for the calculated current density in a membrane's pore as a function of voltage: a quasi-ohmic, slow rising linear current at low voltages; a nonlinear current at intermediate voltages; and a non-ohmic, fast rising linear current at large voltages. The slope of the quasi-ohmic current depends mainly on the height of the energy barrier inside the pore, w, through an exponential term, ew. The magnitude of the non-ohmic linear current is controlled by the potential energy gradient at the pore entrance, w/r. The current-voltage relationship is asymmetric if the ion's potential energy inside the pore has an asymmetric triangular profile. The model has only two assumed parameters, the energy barrier height, w, and the relative size of the entrance region of th...
2008 30th Annual International Conference of the Ieee Engineering in Medicine and Biology Society, Vols 1-8, 2008
The skin electrical properties are identified using a standard NeuroMuscular Electrical Stimulati... more The skin electrical properties are identified using a standard NeuroMuscular Electrical Stimulation (NMES) voltage pulse. The three component series equivalent electrical model was chosen to account for the skin electrical properties. The values of each of these three electrical components of the equivalent electrical model were identified and compared throughout 40 minute daily NMES sessions and over 5 days. Current measurements were performed during the NMES sessions in a non-invasive way, in order to assess changes occuring during each stimulation session and due to long-term NMES.
2009 Annual International Conference of the Ieee Engineering in Medicine and Biology Society, Vols 1-20, 2009
We propose a new method for extracting the electrical properties of human skin based on the time ... more We propose a new method for extracting the electrical properties of human skin based on the time constant analysis of its exponential response to impulse stimulation. As a result of this analysis an adjacent finding has arisen. We have found that stratum corneum electroporation can be detected using this analysis method. We have observed that a one time-constant model is appropriate for describing the electrical properties of human skin at low amplitude applied voltages (<30V), and a two time-constant model best describes skin electrical properties at higher amplitude applied voltages (>30V). Higher voltage amplitudes (>30V) have been proven to create pores in the skin's stratum corneum which offer a new, lower resistance, pathway for the passage of current through the skin. Our data shows that when pores are formed in the stratum corneum they can be detected, in-vivo, due to the fact that a second time constant describes current flow through them.
Particular neuromuscular electrical stimulation (NMES) applications require the use of the same e... more Particular neuromuscular electrical stimulation (NMES) applications require the use of the same electrodes over a long duration (>1 day) without having access to them. Under such circumstance the quality of the electrode-skin contact cannot be assessed. We used the NMES signal itself to assess the quality of the electrode-skin contact and the electrical properties of the underlying tissues over a week. A 14% decrease in the skin's stratum corneum resistance (from 20 to 17 kΩ) and a 15% decrease in the resistance of the electrodes and underlying tissues (from 550 to 460 Ω) were observed in the 14 healthy subjects investigated. A follow-on investigation of the effect of exercise-induced sweating on the electrical properties of the electrode-skin-underlying tissue composite during NMES indicated a correlation between the decrease in the resistance values observed over the course of the week and the accumulation of sweat at the electrode-skin interface. The value of the capacitance representing the dielectric properties of the skin's stratum corneum increased after exercise-induced sweating but did not change significantly over the course of the week. We conclude that valuable information about the electrode-skin-underlying tissue composite can be gathered using the NMES signal itself, and suggest that this is a practical, safe and relatively simple method for monitoring these electrical properties during long-term stimulation.
We studied the asymmetry of skin response to a constant current pulse (4mA/0.1ms) of positive or ... more We studied the asymmetry of skin response to a constant current pulse (4mA/0.1ms) of positive or negative polarity, followed by a free decay of skin's potential. Negative polarity pulse is related with a lower skin resistance and higher electrical capacity. This behavior corresponds to 2 of the 3 relaxation times found in our skin measurements.
... Romania, Medical Engineering, e-mail: [email protected]. E. Culea is with the Technic... more ... Romania, Medical Engineering, e-mail: [email protected]. E. Culea is with the Technical University of Cluj-Napoca, Romania, Physics Department, phone: +40-264-401-260; e???mail: [email protected]. ...
THE ELECTRIC CAPACITY OF THE HUMAN SKIN. Nicolae-Marius BÂRLEA, Sânziana Iulia BÂRLEA. Tehnical U... more THE ELECTRIC CAPACITY OF THE HUMAN SKIN. Nicolae-Marius BÂRLEA, Sânziana Iulia BÂRLEA. Tehnical University of Cluj-Napoca,Physics Department, Str. C. Daicoviciu 15, ROMANIA,. E-mail: [email protected]. ...
ACOUSTIC MEASUREMENT OF GAS COMPOSITION. Nicolae-Marius Bârlea. Tehnical University of Cluj-Napoc... more ACOUSTIC MEASUREMENT OF GAS COMPOSITION. Nicolae-Marius Bârlea. Tehnical University of Cluj-Napoca,Physics Department, Str. C. Daicoviciu 15, ROMANIA,. E-mail: [email protected]. The gas composition measurement ...
THE IMPORTANCE OF THE SKIN GALVANIC RESPONSE ON CERTAIN POINTS. Nicolae-Marius BÂRLEA, Adina MAN.... more THE IMPORTANCE OF THE SKIN GALVANIC RESPONSE ON CERTAIN POINTS. Nicolae-Marius BÂRLEA, Adina MAN. Technical University of Cluj-Napoca, Physics Department, Str. C. Daicoviciu 15, ROMANIA, E-mail: [email protected]. ABSTRACT. ...
ABSTRACT: Comparative total impedance measurements for normal skin and acupuncture points are pre... more ABSTRACT: Comparative total impedance measurements for normal skin and acupuncture points are presented. The behavior of the impedance and admittance with the frequency for active points and indifferent skin is analyzed. It is indicated the optimum frequency domain for the ...
A model for current-voltage nonlinearity and asymmetry is a good starting point for explaining th... more A model for current-voltage nonlinearity and asymmetry is a good starting point for explaining the electrical behavior of nanopores in synthetic or biological membranes. Using a Nernst-Planck model, we found three behaviors for the calculated current density in a membrane's pore as a function of voltage: a quasi-ohmic, slow rising linear current at low voltages; a nonlinear current at intermediate voltages; and a non-ohmic, fast rising linear current at large voltages. The slope of the quasi-ohmic current depends mainly on the height of the energy barrier inside the pore, w, through an exponential term, ew. The magnitude of the non-ohmic linear current is controlled by the potential energy gradient at the pore entrance, w/r. The current-voltage relationship is asymmetric if the ion's potential energy inside the pore has an asymmetric triangular profile. The model has only two assumed parameters, the energy barrier height, w, and the relative size of the entrance region of th...
It is very important to assess the skin condition for medical or cosmetical reasons. Bioimpedance... more It is very important to assess the skin condition for medical or cosmetical reasons. Bioimpedance Spectroscopy studies the frequency dependence of the electrical impedance of the biological material; the most interesting application would be the skin cancer detection. We studied electrical characteristics of the human skin, RS (series resistance), RP (parallel resistance) and C (capacitance), measuring with electrical impulses. The signal consists of electrical current impulses (width T' = 0.05÷10 ms, the “ON” period) followed by a pause (width T'' = 1÷100 ms, the “OFF” period) when the electrodes cannot receive or transmit current (high impedance status). The potential difference and the current between electrodes are displayed with the oscilloscope. The method allows measuring the characteristics of the skin in a more direct and explicit fashion, and it makes possible to discriminate more phenomena occurring into the skin. The Maxwell-Wagner effect, an interfacial rela...
Electrical methods for the assessment of materials are gaining interest because of their ease of ... more Electrical methods for the assessment of materials are gaining interest because of their ease of implementation. This paper presents some electrical techniques for cement and concrete characterization. For example, electrical resistivity of cement is correlated with its compressive strength and can be used to monitor the real-time evolution of cracking concrete. Archie's laws, which link the electrical conductivity to the material's porosity and to the structure of this porosity (tortuosity) can, estimate the ideal mix of concrete for a specific service life and environmental class. Electrical conductivity measurements can predict the fluid permeability through a porous material (Katz-Thompson formula) and this leads to a better design of pervious concretes for the maximization of water transport. Electrical measurements offer relevant information and versatility, and this makes them ideal for quality control, for designing and assessing construction and building materials.
ABSTRACT In this position paper we present our view of how water is distributed inside the skin&a... more ABSTRACT In this position paper we present our view of how water is distributed inside the skin's stratum corneum to create its electrical properties. The existence of a finite electrical resistance of the skin, especially for direct current, implies a continuous domain of water from the surface of the skin to the inner of the body. We propose water as a third compartment in stratum corneum that interpenetrates the other two compartments: intercellular lipids and corneocytes. We suppose that water exchange between the two generally accepted compartments, intercellular lipids and corneocytes, takes place at the junction between corneodesmosomes and lamellar extracellular lipids. We present the evidences from scientific literature sustaining such a view for water distribution in stratum corneum. This assumption could explain some electrical properties of the skin and why skin's permeability to hydrophilic solutes is better predicted by models that imply a substance transport through corneocytes and lipid bilayers in series.
IET Irish Signals and Systems Conference (ISSC 2008), 2008
Abstract The skin electrical properties are identified using a standard neuromuscular electrical ... more Abstract The skin electrical properties are identified using a standard neuromuscular electrical stimulation voltage pulse. The three component series equivalent electrical model was chosen to account for the skin electrical properties. A mathematical model for the ...
ABSTRACT Using a Nernst-Planck model, we show that the current density in a membrane's po... more ABSTRACT Using a Nernst-Planck model, we show that the current density in a membrane's pore as a function of voltage has three types of behavior: a quasi-ohmic behavior at low voltages, with a small slope, a non-ohmic linear dependence at large voltages, with a large slope, and a nonlinear transition region at intermediate voltages. The magnitude of the quasi-ohmic current from low voltages depends mainly on the height of energy barrier inside the pore, w, through an exponential term, ew. The low voltages domain is experimentally accessible and almost unexplored, despite the fact that it can offer direct information about the energy barrier inside a pore. The model has only two assumed parameters, the energy barrier height, w, and the relative size of the entrance region of the pore, r, with a clear physical meaning, an important advantage for fitting and interpreting experimental data. This simple model for the current-voltage nonlinearity is a good starting point for explaining the electrical behavior of the skin at low voltages. IFMBE Proceedings, 2011, Volume 36, Part 2, 156-159, DOI: 10.1007/978-3-642-22586-4_33 http://www.springerlink.com/content/q6332305485k48u2/
ABSTRACT We have studied the electrical time constants of human skin potential in response to a c... more ABSTRACT We have studied the electrical time constants of human skin potential in response to a constant current impulse (0.4-16 mA/100 us). Three relaxation times were found with values in the range 10-40 us, 100-200 us and 1-4 ms. By correlating the time constants with the electrical model of the skin we found that stratum corneum has a nonlinear resistance that diminishes and a nonlinear capacitance that increases with increasing values of current. IFMBE Proceedings, 2011, Volume 36, Part 2, 160-163, DOI: 10.1007/978-3-642-22586-4_34 http://www.springerlink.com/content/w7573u5j7513j332/
In this paper we present how the main parameters of an optimal velocity model, the velocity adapt... more In this paper we present how the main parameters of an optimal velocity model, the velocity adaptation time, τ, and the desired time gap between consecutive vehicles (time headway), T, control the structure of vehicular traffic flow. We show that the ratio between the desired time gap and the velocity adaptation time, T /τ, establishes the pattern formation in congested traffic flow. This ratio controls both the collective behavior and the individual response of vehicles in traffic. We also introduced a response (transfer) function, which shows how perturbation is transmitted between adjacent vehicles and permits the study of collective stability of traffic flow.
A model for current-voltage nonlinearity and asymmetry is a good starting point for explaining th... more A model for current-voltage nonlinearity and asymmetry is a good starting point for explaining the electrical behavior of nanopores in synthetic or biological membranes. Using a Nernst-Planck model, we found three behaviors for the calculated current density in a membrane's pore as a function of voltage: a quasi-ohmic, slow rising linear current at low voltages; a nonlinear current at intermediate voltages; and a non-ohmic, fast rising linear current at large voltages. The slope of the quasi-ohmic current depends mainly on the height of the energy barrier inside the pore, w, through an exponential term, ew. The magnitude of the non-ohmic linear current is controlled by the potential energy gradient at the pore entrance, w/r. The current-voltage relationship is asymmetric if the ion's potential energy inside the pore has an asymmetric triangular profile. The model has only two assumed parameters, the energy barrier height, w, and the relative size of the entrance region of th...
2008 30th Annual International Conference of the Ieee Engineering in Medicine and Biology Society, Vols 1-8, 2008
The skin electrical properties are identified using a standard NeuroMuscular Electrical Stimulati... more The skin electrical properties are identified using a standard NeuroMuscular Electrical Stimulation (NMES) voltage pulse. The three component series equivalent electrical model was chosen to account for the skin electrical properties. The values of each of these three electrical components of the equivalent electrical model were identified and compared throughout 40 minute daily NMES sessions and over 5 days. Current measurements were performed during the NMES sessions in a non-invasive way, in order to assess changes occuring during each stimulation session and due to long-term NMES.
2009 Annual International Conference of the Ieee Engineering in Medicine and Biology Society, Vols 1-20, 2009
We propose a new method for extracting the electrical properties of human skin based on the time ... more We propose a new method for extracting the electrical properties of human skin based on the time constant analysis of its exponential response to impulse stimulation. As a result of this analysis an adjacent finding has arisen. We have found that stratum corneum electroporation can be detected using this analysis method. We have observed that a one time-constant model is appropriate for describing the electrical properties of human skin at low amplitude applied voltages (<30V), and a two time-constant model best describes skin electrical properties at higher amplitude applied voltages (>30V). Higher voltage amplitudes (>30V) have been proven to create pores in the skin's stratum corneum which offer a new, lower resistance, pathway for the passage of current through the skin. Our data shows that when pores are formed in the stratum corneum they can be detected, in-vivo, due to the fact that a second time constant describes current flow through them.
Particular neuromuscular electrical stimulation (NMES) applications require the use of the same e... more Particular neuromuscular electrical stimulation (NMES) applications require the use of the same electrodes over a long duration (>1 day) without having access to them. Under such circumstance the quality of the electrode-skin contact cannot be assessed. We used the NMES signal itself to assess the quality of the electrode-skin contact and the electrical properties of the underlying tissues over a week. A 14% decrease in the skin's stratum corneum resistance (from 20 to 17 kΩ) and a 15% decrease in the resistance of the electrodes and underlying tissues (from 550 to 460 Ω) were observed in the 14 healthy subjects investigated. A follow-on investigation of the effect of exercise-induced sweating on the electrical properties of the electrode-skin-underlying tissue composite during NMES indicated a correlation between the decrease in the resistance values observed over the course of the week and the accumulation of sweat at the electrode-skin interface. The value of the capacitance representing the dielectric properties of the skin's stratum corneum increased after exercise-induced sweating but did not change significantly over the course of the week. We conclude that valuable information about the electrode-skin-underlying tissue composite can be gathered using the NMES signal itself, and suggest that this is a practical, safe and relatively simple method for monitoring these electrical properties during long-term stimulation.
We studied the asymmetry of skin response to a constant current pulse (4mA/0.1ms) of positive or ... more We studied the asymmetry of skin response to a constant current pulse (4mA/0.1ms) of positive or negative polarity, followed by a free decay of skin's potential. Negative polarity pulse is related with a lower skin resistance and higher electrical capacity. This behavior corresponds to 2 of the 3 relaxation times found in our skin measurements.
... Romania, Medical Engineering, e-mail: [email protected]. E. Culea is with the Technic... more ... Romania, Medical Engineering, e-mail: [email protected]. E. Culea is with the Technical University of Cluj-Napoca, Romania, Physics Department, phone: +40-264-401-260; e???mail: [email protected]. ...
THE ELECTRIC CAPACITY OF THE HUMAN SKIN. Nicolae-Marius BÂRLEA, Sânziana Iulia BÂRLEA. Tehnical U... more THE ELECTRIC CAPACITY OF THE HUMAN SKIN. Nicolae-Marius BÂRLEA, Sânziana Iulia BÂRLEA. Tehnical University of Cluj-Napoca,Physics Department, Str. C. Daicoviciu 15, ROMANIA,. E-mail: [email protected]. ...
ACOUSTIC MEASUREMENT OF GAS COMPOSITION. Nicolae-Marius Bârlea. Tehnical University of Cluj-Napoc... more ACOUSTIC MEASUREMENT OF GAS COMPOSITION. Nicolae-Marius Bârlea. Tehnical University of Cluj-Napoca,Physics Department, Str. C. Daicoviciu 15, ROMANIA,. E-mail: [email protected]. The gas composition measurement ...
THE IMPORTANCE OF THE SKIN GALVANIC RESPONSE ON CERTAIN POINTS. Nicolae-Marius BÂRLEA, Adina MAN.... more THE IMPORTANCE OF THE SKIN GALVANIC RESPONSE ON CERTAIN POINTS. Nicolae-Marius BÂRLEA, Adina MAN. Technical University of Cluj-Napoca, Physics Department, Str. C. Daicoviciu 15, ROMANIA, E-mail: [email protected]. ABSTRACT. ...
ABSTRACT: Comparative total impedance measurements for normal skin and acupuncture points are pre... more ABSTRACT: Comparative total impedance measurements for normal skin and acupuncture points are presented. The behavior of the impedance and admittance with the frequency for active points and indifferent skin is analyzed. It is indicated the optimum frequency domain for the ...
A model for current-voltage nonlinearity and asymmetry is a good starting point for explaining th... more A model for current-voltage nonlinearity and asymmetry is a good starting point for explaining the electrical behavior of nanopores in synthetic or biological membranes. Using a Nernst-Planck model, we found three behaviors for the calculated current density in a membrane's pore as a function of voltage: a quasi-ohmic, slow rising linear current at low voltages; a nonlinear current at intermediate voltages; and a non-ohmic, fast rising linear current at large voltages. The slope of the quasi-ohmic current depends mainly on the height of the energy barrier inside the pore, w, through an exponential term, ew. The magnitude of the non-ohmic linear current is controlled by the potential energy gradient at the pore entrance, w/r. The current-voltage relationship is asymmetric if the ion's potential energy inside the pore has an asymmetric triangular profile. The model has only two assumed parameters, the energy barrier height, w, and the relative size of the entrance region of th...
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