###### spectroscopy

- Electrical impedance spectroscopy (EIS) may therefore be able to aid clinicians in differentiating between benign and malignant skin lesions. (diva-portal.org)
- Electrical impedance spectroscopy and the diagnosis of bladder pathology: a pilot study. (ox.ac.uk)
- We assessed the effectiveness of electrical impedance spectroscopy, a method that measures the variation of electrical current flow with frequency through the mucosa, for differentiating various pathological changes in the urothelium. (ox.ac.uk)
- The carbonation process can be quantitatively accessed by a parameter, which can be obtained by means of the electrochemical impedance spectroscopy (EIS)-based electrochemical model. (mdpi.com)

###### cardiography

- Introduction Electric velocimetry (EV) is normally a kind of impedance cardiography, and it is a non-invasive and applicable approach to cardiac result monitoring continuously. (welbourneprimary.com)
- Launch TC-DAPK6 supplier In the 1960s, impedance cardiography originated to monitor cardiac result (CO) . (welbourneprimary.com)
- After several adjustments towards the algorithm [1- impedance cardiography (that's, electric velocimetry (EV)) gadgets have grown to be commercially available. (welbourneprimary.com)
- Impedance cardiography (ICG), also referred to as electrical impedance plethysmography (EIP) or Thoracic Electrical Bioimpedance (TEB) has been researched since the 1940s. (wikipedia.org)
- The use of impedance cardiography in psychophysiological research was pioneered by the publication of an article by Miller and Horvath in 1978. (wikipedia.org)

###### resistance

- This technique is dependant on a big change in level of resistance through the cardiac routine to a transcutaneously used electric AC Rabbit polyclonal to BMPR2 voltage, and can be used to calculate still left ventricular stroke quantity (LVSV), and CO thus. (welbourneprimary.com)
- Hemodynamics is a fluidic counterpart to the Ohm's Law in electronics: pressure is equivalent to voltage, flow to current, vascular resistance to electrical resistance and myocardial work to power. (wikipedia.org)

###### various

- Background Previous studies have shown statistically significant differences in electrical impedance between various cutaneous lesions. (diva-portal.org)

###### shown

- In fact, it is shown by this study that the electrochemical impedance behavior of mortars varies in the process of carbonation. (mdpi.com)

###### Computed Tomography

- However, in contrast to linear x-rays used in Computed Tomography, electric currents travel three dimensionally along the path of least resistivity. (wikipedia.org)

###### Constrained Electrical Impedance

- Glidewell, M., Ng, K.T.: Anatomically Constrained Electrical Impedance Tomography for Anisotropic Bodies Via a Two-step Approach. (springer.com)

###### measurements

- Electrical impedance tomography ( EIT ) is a noninvasive type of medical imaging in which the electrical conductivity , permittivity , and impedance of a part of the body is inferred from surface electrode measurements and used to form a tomographic image of that part. (wikipedia.org)
- Then a small electrical current is passed through the body and measurements are made. (thebody.com)
- Electrical Impedance Tomography (EIT)is a technique based on the injection of small currents and voltage measurements using electrodes on the skin surface generating cross-sectional images representing impedance change in a slice of the thorax. (clinicaltrials.gov)
- R. P. Henderson and J. G. Webster, "Impedance camera for spatially specific measurements of thorax," IEEE Transactions on Biomedical Engineering , vol. 25, no. 3, pp. 250-254, 1978. (hindawi.com)
- F. Yang and R. P. Patterson, "The contribution of the lungs to thoracic impedance measurements: a simulation study based on a high resolution finite difference model," Physiological Measurement , vol. 28, no. 7, pp. (hindawi.com)
- We propose a novel, variational inversion methodology for the electrical impedance tomography problem, where we seek electrical conductivity σ inside a bounded, simply connected domain Ω, given simultaneous measurements of electric currents I and potentials V at the boundary. (rice.edu)
- In electrical impedance tomography the electrical conductivity inside a physical body is computed from electro-static boundary measurements. (aimsciences.org)
- 208 tetrapolar electrical impedance measurements were obtained at 30 frame/s from a 16 electrode EIT system. (spie.org)
- Thus, by recording time-resolved impedance measurements, cell shape changes can be followed in real time with sub-microscopic resolution and can be used for bioanalytic purposes. (wikipedia.org)
- Giaever & Keese: A morphological biosensor for mammalian cells, Nature 366(1993)591-2 Wegener, Zink, Roesen, Galla: Use of electrochemical impedance measurements to monitor b-adrenergic stimulation of bovine aortic endothelial cells. (wikipedia.org)

###### tomography based

- Three-dimensional electrical impedance tomography based on the complete electrode model. (wikipedia.org)

###### reciprocal of impedance

- The reciprocal of impedance is admittance, whose SI unit is the siemens, formerly called mho. (wikipedia.org)
- This result may seem counterintuitive since admittance is the reciprocal of impedance, but is easily proved. (wikipedia.org)

###### electrode

- Data collected using scalp electrode in humans matched known tissue impedance spectra and was stable over frequency. (mdpi.com)
- Methods/Results: In 28 healthy subjects, we assessed electrical impedance of skin and underlying subcutaneous connective tissue using a four needle-electrode approach. (harvard.edu)
- The AC impedance of the cell-covered electrode is then measured at one or several frequencies as a function of time. (wikipedia.org)
- Due to the insulating properties of their membranes the cells behave like dielectric particles so that the impedance increases with increasing coverage of the electrode until a confluent (i.e. continuous) layer of cells is established. (wikipedia.org)

###### conductivity

- Electrical conductivity varies considerably among various biological tissues (absolute EIT) or the movement of fluids and gases within tissues (difference EIT). (wikipedia.org)
- It has been used for investigation of imaging electrical activity in the brain, and monitoring conductivity changes during radio-frequency ablation. (wikipedia.org)
- The impedance has two components: electrical conductivity and dielectric constant. (wikipedia.org)

###### Inverse Problems

- H. Eckel and R. Kress, Nonlinear integral equations for the inverse electrical impedance problem ,, Inverse Problems , 23 (2007), 475. (aimsciences.org)

###### myography

- Electrical impedance myography, or EIM, is a non-invasive technique for the assessment of muscle health that is based on the measurement of the electrical impedance characteristics of individual muscles or groups of muscles. (wikipedia.org)
- These devices rely on the use of electrical impedance myography (EIM) to measure muscle quality. (wikipedia.org)
- Electrical impedance myography in the assessment of disuse atrophy. (wikipedia.org)

###### Spectroscopy

- The majority of EIT systems apply small alternating currents at a single frequency, however, some EIT systems use multiple frequencies to better differentiate between normal and suspected abnormal tissue within the same organ (multifrequency-EIT or electrical impedance spectroscopy). (wikipedia.org)
- In a more recent collaboration, the electrical impedance spectroscopy platform (EISP) was launched together with French Fluigent and Dutch Micronit for the commercialization of ready-to-use electrical impedance analysis system. (wikipedia.org)

###### reactance

- The impedance caused by these two effects is collectively referred to as reactance and forms the imaginary part of complex impedance whereas resistance forms the real part. (wikipedia.org)
- In EIM, impedance is separated into resistance and reactance, its real and imaginary components. (wikipedia.org)
- Because changes in frequency shift the relative contributions of resistance (fluid) and reactance (membrane) to impedance, multifrequency EIM may allow a more comprehensive assessment of disease. (wikipedia.org)
- In bioelectrical impedance analysis in humans, an estimate of the phase angle can be obtained and is based on changes in resistance and reactance as alternating current passes through tissues, which causes a phase shift. (wikipedia.org)
- Foster's reactance theorem is an important theorem in the fields of electrical network analysis and synthesis. (wikipedia.org)
- Reactance is the imaginary part of the complex electrical impedance. (wikipedia.org)
- If the impedance is Z = i X {\displaystyle Z=iX\,} where X {\displaystyle \scriptstyle X} is reactance and i {\displaystyle \scriptstyle i} is the imaginary unit, then the admittance is given by Y = 1 i X = − i 1 X = i B {\displaystyle Y={\frac {1}{iX}}=-i{\frac {1}{X}}=iB} where B {\displaystyle \scriptstyle B} is susceptance. (wikipedia.org)
- The impedance of an inductor is given by, Z = i ω L {\displaystyle Z=i\omega L\,} L {\displaystyle \scriptstyle L} is inductance ω {\displaystyle \scriptstyle \omega } is angular frequency so the reactance is, X = ω L {\displaystyle X=\omega L\,} which by inspection can be seen to be monotonically (and linearly) increasing with frequency. (wikipedia.org)
- The impedance of a capacitor is given by, Z = 1 i ω C {\displaystyle Z={\frac {1}{i\omega C}}} C {\displaystyle \scriptstyle C} is capacitance so the reactance is, X = − 1 ω C {\displaystyle X=-{\frac {1}{\omega C}}} which again is monotonically increasing with frequency. (wikipedia.org)
- A series LC circuit has an impedance that is the sum of the impedances of an inductor and capacitor, Z = i ω L + 1 i ω C = i ( ω L − 1 ω C ) {\displaystyle Z=i\omega L+{\frac {1}{i\omega C}}=i\left(\omega L-{\frac {1}{\omega C}}\right)} At low frequencies the reactance is dominated by the capacitor and so is large and negative. (wikipedia.org)

###### Reconstruction

- In electrical impedance tomography (EIT), various image reconstruction algorithms have been used in order to compute the internal resistivity distribution of the unknown object with its electric potential data at the boundary. (springer.com)
- EIDORS is an open-source software tool box written mainly in MATLAB/GNU Octave designed primarily for image reconstruction from electrical impedance tomography(EIT) data, in a biomedical, industrial or geophysical setting. (wikipedia.org)
- The name was originally an acronym for Electrical Impedance Tomography and Diffuse Optical Reconstruction Software. (wikipedia.org)
- Polydorides N, Lionheart WRB, A Matlab toolkit for three-dimensional electrical impedance tomography: a contribution to the Electrical Impedance and Diffuse Optical Reconstruction Software project, Meas. (wikipedia.org)

###### 1990

- Electrical termination Electrical impedance Grid resistor Kleinschmidt, Kirk, ed. (1990). (wikipedia.org)

###### admittance

- It is often the case in network theory that a principle or procedure applies equally well to impedance or admittance-reflecting the principle of duality for electric networks. (wikipedia.org)
- It is convenient in these circumstances to use the concept of immittance, which can mean either impedance or admittance. (wikipedia.org)
- The impedance function of the capacitor is identical to the admittance function of the inductor and vice versa. (wikipedia.org)

###### capacitance

- The introduction of the concept of impedance in AC circuit is justified by the fact that there are two additional impeding mechanisms to be taken into account besides the normal resistance of DC circuits: the induction of voltages in conductors self-induced by the magnetic fields of currents (inductance), and the electrostatic storage of charge induced by voltages between conductors (capacitance). (wikipedia.org)
- These can generate an impedance equivalent to a negative inductance or capacitance. (wikipedia.org)

###### displaystyle

- Quantitatively, the impedance of a two-terminal network is represented as a complex quantity Z {\displaystyle \scriptstyle Z} , defined in Cartesian form as Z = R + j X . {\displaystyle \ Z=R+jX. (wikipedia.org)
- j {\displaystyle \scriptstyle j} is the imaginary unit, and is used instead of i {\displaystyle \scriptstyle i} in this context to avoid confusion with the symbol for electric current. (wikipedia.org)
- The impedance of a two-terminal circuit element is represented as a complex quantity Z {\displaystyle \scriptstyle Z} and the term complex impedance may also be used. (wikipedia.org)
- The Poincaré-Steklov operator is defined to be the operator mapping the time-harmonic (that is, dependent on time as e i ω t {\displaystyle e^{i\omega t}} ) tangential electric field on the boundary of a region to the equivalent electric current on its boundary. (wikipedia.org)

###### circuits

- Impedance extends the concept of resistance to AC circuits, and possesses both magnitude and phase, unlike resistance, which has only magnitude. (wikipedia.org)
- In alternating current circuits, electrical impedance is also measured in ohms. (wikipedia.org)

###### tissue

- Studies using an electrical impedance probe indicate that early tissue cell abnormalities can be immediately identified, effectively meaning that women could be sent for further investigation and treatment much more quickly. (medgadget.com)
- In tissue cells, low frequency electrical currents travel around cells and can inform doctors of cell shapes and how they are arranged. (medgadget.com)
- Like all impedance-based methods, EIM hinges on a simplified model of muscle tissue as an RC circuit. (wikipedia.org)
- EIM captures these changes in the tissue as a whole by measuring its impedance characteristics across multiple frequencies and at multiple angles relative to the major muscle fiber direction. (wikipedia.org)
- Because of electrical impedance of the pulmonal tissue is dependant to the air content, the air distribution within the lung over a certain period can be monitored. (clinicaltrials.gov)
- Past studies have suggested that acupuncture meridians are physiologically characterized by low electrical impedance and anatomically associated with connective tissue planes. (harvard.edu)

###### Device

- To overcome this difficulty it has been proposed to provide a device known as a gyrator, which has the property of producing at one port an impedance which is proportional to the inverse of the impedance connected across another port, so that if a capacitor is connected across the other port the device, together with the capacitor, when viewed from the one port behaves like an inductor. (google.com)
- We used a commercial impedance sensing device (ECIS®) to assess the migration of the cells following irradiation. (aps.org)
- A dummy load is a device used to simulate an electrical load, usually for testing purposes. (wikipedia.org)

###### Webster

- John O.G. Webster is an American electrical engineer and a founding pioneer in the field of biomedical engineering. (wikipedia.org)
- In his spare time, Webster works with undergraduate biomedical engineering design teams at the University of Wisconsin-Madison, including ongoing projects with impedance cardiography and atrial fibrillation. (wikipedia.org)

###### electrodes

- Time difference EIT (td-EIT) has one major advantage over absolute EIT (a-EIT): inaccuracies resulting from interindividual anatomy, insufficient skin contact of surface electrodes or impedance transfer can be dismissed because most artifacts will eliminate themselves due to simple image subtraction in f-EIT. (wikipedia.org)
- For the two dimensional inverse electrical impedance problem in the case of piecewise constant conductivities with the currents injected at adjacent point electrodes and the resulting voltages measured between the remaining electrodes, in the authors proposed a nonlinear integral equation approach that extends a method that has been suggested by Kress and Rundell for the case of perfectly conducting inclusions. (aimsciences.org)

###### linearly

- In multiple port networks, the two-terminal definition of impedance is inadequate, but the complex voltages at the ports and the currents flowing through them are still linearly related by the impedance matrix. (wikipedia.org)

###### relates

- For a sinusoidal current or voltage input, the polar form of the complex impedance relates the amplitude and phase of the voltage and current. (wikipedia.org)
- Ava/rs S Huron/cu INVENTOR BY zaa iid dar ATTORNEY ELECTRICAL IMPEDANCE CONVERTING NETWORKS This invention relates to electrical impedance networks of the type which are capable of simulating inductances without the use of physical inductors. (google.com)

###### Electromagnetic

- Electromagnetic waves traveling along Transmission Line (TL) enter in soil medium whose impedance is different from TL a part of the energy is reflected back to transmitter. (wikipedia.org)
- These units had the great advantage of simplifying the equations used in the solution of electromagnetic problems, and eliminated conversion factors in calculations about electrical quantities. (wikipedia.org)

###### frequency

- Impedance is defined as the frequency domain ratio of the voltage to the current. (wikipedia.org)
- Avery J, Dowrick T, Faulkner M, Goren N, Holder D. A Versatile and Reproducible Multi-Frequency Electrical Impedance Tomography System. (mdpi.com)

###### differences

- We are interested in seeing whether acupuncture meridians are associated with lower electrical impedance and whether ultrasound-derived measures - specifically echogenic collagenous bands - can account for these impedance differences. (harvard.edu)
- Age- and gender-associated differences in electrical impedance values of skeletal muscle. (wikipedia.org)

###### measurement

- Influence of heart motion on cardiac output estimation by means of electrical impedance tomography: a case study Physiological Measurement 2015 36 1075 Kirill Y. Aristovich et al Imaging fast electrical activity in the brain with electrical impedance tomography NeuroImage 2016 124 204 Hun Wi et al. (wikipedia.org)

###### inductive

- When a network is capacitively terminated it input port impedance is inductive. (google.com)

###### current

- This means, that a part of the electric current leaves the transverse plane and results in an impedance transfer. (wikipedia.org)
- The electrical current is so small that it can not be felt at all. (thebody.com)
- Electrical impedance is the measure of the opposition that a circuit presents to a current when a voltage is applied. (wikipedia.org)
- Quantitatively, the impedance of a two-terminal circuit element is the ratio of the complex representation of a sinusoidal voltage between its terminals to the complex representation of the current flowing through it. (wikipedia.org)
- the phase of the complex impedance is the phase shift by which the current lags the voltage. (wikipedia.org)
- If cell shape changes occur, the current pathways through and around the cell bodies change as well, leading to a corresponding increase or decrease of impedance. (wikipedia.org)
- This then causes more channels to open, producing a greater electric current across the cell membrane, and so on. (wikipedia.org)
- The devices are handheld and are pressed against the skin area corresponding to a specific muscle group, an electrical current flows, impedance is measured and the output is a muscle quality score. (wikipedia.org)
- In this case, the phase angle is the phase difference between the voltage applied to the impedance and the current driven through it. (wikipedia.org)
- A fault current limiter is a nonlinear element which has a low impedance at normal current levels, but presents a higher impedance at fault current levels. (wikipedia.org)
- From 1959 until 1973 Ranck analyzed the flow of electric current in brain, electrical properties of glia, electric impedance of brain, release of potassium from neurons in a seizure, and which elements are activated in electric stimulation of brain. (wikipedia.org)
- Alternatively, the electrical units can be related to the mechanical units by defining, for example, a unit of current that gives a specified force between two wires, or a unit of charge that gives a unit of force between two unit charges. (wikipedia.org)

###### Grid

- This poses a particular problem when distributed generation, such as wind farms and rooftop solar power, is added to an existing electric grid. (wikipedia.org)

###### amplitude

- The impedance can be measured from difference in amplitude. (wikipedia.org)

###### methods

- Two different methods of establishing a system of electrical units can be chosen. (wikipedia.org)

###### imaginary

- The network consequently must consist entirely of inductors and capacitors and the impedance will be purely an imaginary number with zero real part. (wikipedia.org)

###### phase angle

- the latter can be thought of as impedance with zero phase angle. (wikipedia.org)

###### frequencies

- The impedances were obtained at 10 kHz and 100 kHz frequencies and at three body sites - upper arm (Large Intestine meridian), thigh (Liver), and lower leg (Bladder). (harvard.edu)
- We found significantly reduced electrical impedance at the Large Intestine meridian compared to adjacent control for both frequencies. (harvard.edu)

###### increases

- Using a unique and proprietary concept of magnetic-flux alteration - requiring no superconducting or cryogenic components - the self-triggered FCL instantaneously increases its impedance tenfold upon fault condition. (wikipedia.org)

###### parallel

- A circuit calculation, such as finding the total impedance of two impedances in parallel, may require conversion between forms several times during the calculation. (wikipedia.org)

###### decrease

- No significant decrease in impedance was found at the Liver or Bladder meridian. (harvard.edu)

###### procedure

- Bio-electrical Impedance Analysis (BIA) is a simple painless procedure which enables a doctor or healthcare provider to analyze the amounts of fat, muscle and water in the body. (thebody.com)

###### data

- In the early phase Ranck studied impedance in the brain, providing basic data for any studies or procedures that employ electrical stimulation of the CNS. (wikipedia.org)

###### Imaging

- Electrical impedance tomography (EIT) is a noninvasive tool that allows real-time imaging of regional ventilation. (ovid.com)
- He first proposed the idea of electrical impedance tomography as a medical imaging technique in a publication in 1978. (wikipedia.org)

###### currents

- The notion of impedance is useful for performing AC analysis of electrical networks, because it allows relating sinusoidal voltages and currents by a simple linear law. (wikipedia.org)

###### liver

- In this study we assess the feasibility of electrical impedance tomography (EIT) to track the temperature changes during ablation in an ex-vivo ovine liver and in-vivo porcine model. (spie.org)
- In the porcine model ventilation artefact was removed by low pass filtering and successful ablation related impedance change image sequences were reconstructed from four of nine liver ablations. (spie.org)

###### detection

- S. OLLMAR and L. EMTESTAM, "Electrical impedance applied to non-invasive detection of irritation in skin", Contact Dermatitus, in press . (springer.com)

###### ratio

- The ideal dummy load provides a standing wave ratio (SWR) of 1:1 at the given impedance. (wikipedia.org)

###### evaluation

- Evaluation of Electrical Impedance as a Biomarker of Myostatin Inhibition in Wild Type and Muscular Dystrophy Mice. (wikipedia.org)

###### 1967

- of Rochester, NY 1967 Instructor in Electrical Eng. (wikipedia.org)
- In 1967, while analyzing the biophysical properties of the subiculum he found that impedance increased in REM sleep. (wikipedia.org)

###### stimulation

- Which elements are excited in electrical stimulation of mammalian central nervous system: a review. (wikipedia.org)

###### measures

- Muscle composition and microscopic structure change with disease, and EIM measures alterations in impedance that occur as a result of disease pathology. (wikipedia.org)
- This method measures the electrical impedance. (wikipedia.org)

###### amplifiers

- Used for small venue PA cabinets and small stage monitor speakers (with a horn), and lightweight bass guitar or electric guitar combination amplifiers ("combos") and cabinets designed for rehearsal monitoring or practice. (wikipedia.org)

###### technique

- A technique similar to EIT is used in geophysics and industrial process monitoring - electrical resistivity tomography. (wikipedia.org)
- The potential for dental materials to irritate human oral mucosal membranes was assessed by an electrical impedance technique. (springer.com)

###### cell

- Scientists experimented with variations on this model until 1940, when Kenneth Cole developed a circuit model that accounted for the impedance properties of both cell membranes and intracellular fluid. (wikipedia.org)
- Electric cell-substrate impedance sensing or ECISTM (a trademark of Applied BioPhysics Inc.) refers to a non-invasive biophysical approach to monitor living animal cells in vitro, i.e. within a well-defined laboratory environment. (wikipedia.org)
- In confluent cell layers the measured impedance is mainly determined by the three-dimensional shape of the cells. (wikipedia.org)
- The electrical properties of a cell are determined by the structure of the membrane that surrounds it. (wikipedia.org)

###### Analysis

- B. Jin and P. Maass, An analysis of electrical impedance tomography with applications to Tikhonov regularization,, ESAIM: Control , 18 (2012), 1027. (aimsciences.org)

###### changes

- Impedance changes in lung ventilation are investigated in mechanically ventilated patients who routinely undergo bronchoscopy in intensive care medicine. (clinicaltrials.gov)

###### skin

- Skin impedance was reduced by inundation with ECG-gel. (springer.com)

###### quantities

- The rapid rise of electrotechnology in the last half of the 19th century created a demand for a rational, coherent, consistent, and international system of units for electrical quantities. (wikipedia.org)

###### found

- Electrical impedance technology was found to be more sensitive than traditional visual registration of mucosal reactions. (springer.com)

###### model

- Interest in electrical impedance dates back to the turn of the 20th century, when physiologist Louis Lapicque postulated an elementary circuit to model membranes of nerve cells. (wikipedia.org)

###### case

- Electric power distribution systems include circuit breakers to disconnect power in case of a fault, but to maximize reliability, they wish to disconnect the smallest possible portion of the network. (wikipedia.org)

###### CIRCUITS

- Impedance extends the concept of resistance to AC circuits, and possesses both magnitude and phase, unlike resistance, which has only magnitude. (wikipedia.org)

###### Measurement

- Influence of heart motion on cardiac output estimation by means of electrical impedance tomography: a case study Physiological Measurement 2015 36 1075 Kirill Y. Aristovich et al Imaging fast electrical activity in the brain with electrical impedance tomography NeuroImage 2016 124 204 Hun Wi et al. (wikipedia.org)

###### Transmission Line

- Electromagnetic waves traveling along Transmission Line (TL) enter in soil medium whose impedance is different from TL a part of the energy is reflected back to transmitter. (wikipedia.org)

###### measure

- hence, a muscle's impedance can be used to measure the tissue's degradation in disease progression. (wikipedia.org)

###### circuit

- The negative impedance converter is an example of such a circuit. (wikipedia.org)
- A simple solution is to add electrical impedance to the circuit. (wikipedia.org)

###### phase

- the latter can be thought of as impedance with zero phase angle. (wikipedia.org)