scholarly journals Analysis of impedance measurements of a suspension of microcapsules using a variable length impedance measurement cell

2019 ◽  
Vol 3 (1) ◽  
pp. 42-50 ◽  
Author(s):  
Dejan Križaj ◽  
Borut Pečar
Keyword(s):  
Electrical Properties ◽  
Double Layer ◽  
Electrical Impedance ◽  
Impedance Measurement ◽  
Measured Data ◽  
Electrode Impedance ◽  
Impedance Measurements ◽  
Measuring Cell ◽  
Lumped Models ◽  
Measurement Cell

Abstract Electrical impedance measurements of a suspension have to take into account the double layer impedance that results from a very thin charged layer formed at the electrode-electrolyte interface. A dedicated measuring cell that enables variation of the distance between the electrodes was developed to investigate the electrical properties of suspensions using two-electrode impedance measurements. By varying the distance between the electrodes it is possible to separate the double layer and the suspension impedance from the measured data. Electrical ‘lumped’ models have been developed from measured and extracted impedances. The error of non-inclusion of the double layer impedance has been analyzed. The error depends on the frequency of the measurement as well as the distance between the electrodes.

scholarly journals Low Cost Instrumentation for Electrical Impedance Tomography in Biomedical Applications

2015 ◽  
Author(s):  
Stewart Smith ◽  
Hancong Wu ◽  
Jiabin Jia
Keyword(s):  
Electrical Impedance Tomography ◽  
Integrated Circuit ◽  
Biomedical Applications ◽  
Electrical Impedance ◽  
Low Cost ◽  
Impedance Measurement ◽  
Impedance Tomography ◽  
Impedance Measurements ◽  
Additional Circuitry ◽  
Initial Results

This poster reports the design, implementation and testing of a portable and inexpensive bio-impedance measurement system intended for electrical impedance tomography (EIT) in cell cultures. The system is based on the AD5933 impedance analyser integrated circuit with additional circuitry to enable four-terminal measurement. Initial results of impedance measurements are reported along with an EIT image reconstructed using the open source EIDORS package.

Electrical Impedance Measurements of PZT Nanofiber Sensors

2016 ◽  
Author(s):  
Richard Galos ◽  
Xin Li
Keyword(s):  
Dielectric Constant ◽  
Material Properties ◽  
Electrical Impedance ◽  
Impedance Measurement ◽  
Low Frequencies ◽  
Impedance Measurements ◽  
Conductive Afm ◽  
Electrical Impedance Measurement ◽  
Microfabrication Techniques

Electrical Impedance Measurement of PZT Nanofiber sensors are performed and material properties including resistivity and dielectric constant are derived from the measurements. Nanofibers formed by electro-spinning with diameters ranging from 10 to 150 nm were collected and integrated into sensors using microfabrication techniques. The nanosensor impedance was extremely high at low frequencies and special matching circuitry was fabricated to detect output. The resulting impedance measurements are also compared with those of individual nanofibers that were tested using Scanning Conductive Microscopy (SCM) and Conductive AFM.

scholarly journals Apple Bruise Detection by Electrical Impedance Measurement

HortScience ◽  
2000 ◽  
Vol 35 (1) ◽  
pp. 104-107 ◽  
Author(s):  
Phillipa J. Jackson ◽  
F. Roger Harker
Keyword(s):  
Electrical Impedance ◽  
Impedance Measurement ◽  
Apple Fruit ◽  
Fruit Weight ◽  
Electrical Impedance Spectroscopy ◽  
Apple Cultivar ◽  
Impedance Measurements ◽  
Before And After ◽  
Electrical Impedance Measurement ◽  
Further Development

Electrical impedance was used to determine the extent of tissue damage that occurred as a result of bruising of apple fruit (Malus ×domestica Borkh, cvs. Granny Smith and Splendour). Impedance measurements were made before and after bruising. Plots of reactance against resistance at 36 spot frequencies between 50 Hz and 1 MHz traced a semicircular arc, which contracted in magnitude after bruising. A number of characteristics of these curves were then related to bruise weight. The change in resistance that occurred as a result of fruit impact (ΔR50Hz) was the best predictor of bruise weight, with r2 values up to 0.71. Before bruising, resistance of fruit was higher in `Splendour' than in `Granny Smith' (P < 0.001), and at 0 °C than at 20 °C (P < 0.001), but was not influenced by fruit weight. The influence of apple cultivar and temperature on electrical impedance may cause difficulties when implementing these measurements in a commercial situation. However, further development of electrical impedance spectroscopy methodologies may result in convenient research techniques for assessing bruise weight without having to wait for browning of the flesh.

scholarly journals Assessing ischemic injury in human intestine ex vivo with electrical impedance spectroscopy

2021 ◽  
Vol 12 (1) ◽  
pp. 82-88
Author(s):  
Jie Hou ◽  
Runar Strand-Amundsen ◽  
Stina Hødnebø ◽  
Tor Inge Tønnessen ◽  
Jan Olav Høgetveit
Keyword(s):  
Electrical Properties ◽  
Impedance Spectroscopy ◽  
Electrical Impedance ◽  
Electrical Impedance Spectroscopy ◽  
Time Interval ◽  
Human Intestine ◽  
Impedance Measurements ◽  
Intestinal Segments ◽  
Small Intestinal ◽  
Passive Electrical Properties

Abstract Electrical impedance spectroscopy is a well-established tool for monitoring changes in the electrical properties of tissue. Most tissue and organ types have been investigated in various studies. As for the small intestine, there are several published studies conducted on pig and rat models. This study investigates the changes in passive electrical properties of the complete wall of the human intestine non-invasively during ischemia. We aim to use the passive electrical properties to assess intestinal viability. The bioimpedance measurements were performed using a two-electrode set-up with a Solartron 1260 Impedance/gain-phase analyser. The small intestinal samples were resected from patients who underwent pancreaticoduodenectomy. Impedance measurements were conducted following resection by placing the electrodes on the surface of the intestine. A voltage was applied across the intestinal sample and the measured electrical impedance was obtained in the ZPlot software. Impedance data were further fitted into a Cole model to obtain the Cole parameters. The Py value was calculated from the extracted Cole parameters and used to assess the cell membrane integrity, thus evaluate the intestinal viability. Eight small intestinal segments from different patients were used in this study and impedance measurements were performed once an hour for a ten-hour period. One hour after resection, the impedance decreased, then increased the next two hours, before decreasing until the end of the experiment. For all the intestinal segments, the Py values first increased and reached a plateau which lasted for 1 - 2 hours, before it decreased irreversibly. The time interval where Py value reached the maximum is consistent with reported viable/non-viable limits from histological analysis.

Measurement of Electrical Properties of Sickle Cells From Electrical Impedance of Cell Suspension

2017 ◽  
Author(s):  
Jia Liu ◽  
Yuhao Qiang ◽  
E. Du
Keyword(s):  
Electrical Properties ◽  
Cell Suspension ◽  
Sickle Cell ◽  
Electrical Impedance ◽  
Single Cells ◽  
Impedance Measurement ◽  
Mixture Theory ◽  
Electrical Impedance Spectroscopy ◽  
Electrical Impedance Measurement ◽  
Characteristic Features

Analysis of the electrical properties of a biological cell can provide useful information about its characteristic features, such as the intracellular composition, charge distribution and composition changes in cell membrane, as well as the extracellular environment. Electrical impedance spectroscopy of a cell suspension can be used to extract an average measure of the electrical properties of single cells. In sickle cell disease, the disease state of a sickle red blood cell is closely related to the intracellular hemoglobin composition and concentration. This study presents an electrical impedance measurement of sickle cell suspension with normal red blood cells as control. Electrical impedance spectra of cell suspensions are obtained in the range of 1000 Hz to 1MHz. Based on Maxwell’s mixture theory, average values of membrane capacitance and cytoplasm resistance of single cells are extracted for both normal and sickle blood samples. Comparing to traditional parallel-plate setup for cell suspension subjected to frequency sweep, this method requires low quantity of blood specimens and can be potentially valuable for patients that are already anemic.

scholarly journals Electrical Impedance Spectroscopy as Electrical Biopsy for Monitoring Radiation Sequelae of Intestine in Rats

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Pei-Ju Chao ◽  
Eng-Yen Huang ◽  
Kuo-Sheng Cheng ◽  
Yu-Jie Huang
Keyword(s):  
Electrical Properties ◽  
Impedance Spectroscopy ◽  
Integrated Circuits ◽  
Electrical Impedance ◽  
Roc Analysis ◽  
Electrical Impedance Spectroscopy ◽  
Electrical Characteristics ◽  
Injury Score ◽  
Histological Changes ◽  
Radiation Sequelae

Electrical impedance is one of the most frequently used parameters for characterizing material properties. The resistive and capacitive characteristics of tissue may be revealed by electrical impedance spectroscopy (EIS) as electrical biopsy. This technique could be used to monitor the sequelae after irradiation. In this study, rat intestinal tissues after irradiation were assessed by EIS system based on commercially available integrated circuits. The EIS results were fitted to a resistor-capacitor circuit model to determine the electrical properties of the tissue. The variations in the electrical characteristics of the tissue were compared to radiation injury score (RIS) by morphological and histological findings. The electrical properties, based on receiver operation curve (ROC) analysis, strongly reflected the histological changes with excellent diagnosis performance. The results of this study suggest that electrical biopsy reflects histological changes after irradiation. This approach may significantly augment the evaluation of tissue after irradiation. It could provide rapid results for decision making in monitoring radiation sequelae prospectively.

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