The resistance to the flow of either alternating or direct electrical current.
Recording changes in electrical impedance between electrodes placed on opposite sides of a part of the body, as a measure of volume changes in the path of the current. (Stedman, 25th ed)
A type of impedance plethysmography in which bioelectrical impedance is measured between electrodes positioned around the neck and around the lower thorax. It is used principally to calculate stroke volume and cardiac volume, but it is also related to myocardial contractility, thoracic fluid content, and circulation to the extremities.
In about 250 species of electric fishes, modified muscle fibers forming disklike multinucleate plates arranged in stacks like batteries in series and embedded in a gelatinous matrix. A large torpedo ray may have half a million plates. Muscles in different parts of the body may be modified, i.e., the trunk and tail in the electric eel, the hyobranchial apparatus in the electric ray, and extrinsic eye muscles in the stargazers. Powerful electric organs emit pulses in brief bursts several times a second. They serve to stun prey and ward off predators. A large torpedo ray can produce of shock of more than 200 volts, capable of stunning a human. (Storer et al., General Zoology, 6th ed, p672)
A technique of measuring the dielectric properties of materials, which vary over a range of frequencies depending on the physical properties of the material. The technique involves measuring, over a range of frequencies, ELECTRICAL IMPEDANCE and phase shift of an electric field as it passes through the material.
Fields representing the joint interplay of electric and magnetic forces.
An order of neotropical electric fish found chiefly in the waters of South America. They continually emit weak electric discharges, which they use in object location and communication. A most popular species of research interest is the electric eel, ELECTROPHORUS electricus.
Imaging methods that result in sharp images of objects located on a chosen plane and blurred images located above or below the plane.
Works containing information articles on subjects in every field of knowledge, usually arranged in alphabetical order, or a similar work limited to a special field or subject. (From The ALA Glossary of Library and Information Science, 1983)
Electric conductors through which electric currents enter or leave a medium, whether it be an electrolytic solution, solid, molten mass, gas, or vacuum.
Devices or objects in various imaging techniques used to visualize or enhance visualization by simulating conditions encountered in the procedure. Phantoms are used very often in procedures employing or measuring x-irradiation or radioactive material to evaluate performance. Phantoms often have properties similar to human tissue. Water demonstrates absorbing properties similar to normal tissue, hence water-filled phantoms are used to map radiation levels. Phantoms are used also as teaching aids to simulate real conditions with x-ray or ultrasonic machines. (From Iturralde, Dictionary and Handbook of Nuclear Medicine and Clinical Imaging, 1990)
The relative amounts of various components in the body, such as percentage of body fat.
Fluids composed mainly of water found within the body.
The technique that deals with the measurement of the size, weight, and proportions of the human or other primate body.
The use of specifically placed small electrodes to deliver electrical impulses across the SKIN to relieve PAIN. It is used less frequently to produce ANESTHESIA.
Surgically placed electric conductors through which ELECTRIC STIMULATION is delivered to or electrical activity is recorded from a specific point inside the body.
Application of electric current in treatment without the generation of perceptible heat. It includes electric stimulation of nerves or muscles, passage of current into the body, or use of interrupted current of low intensity to raise the threshold of the skin to pain.
Therapy for MOVEMENT DISORDERS, especially PARKINSON DISEASE, that applies electricity via stereotactic implantation of ELECTRODES in specific areas of the BRAIN such as the THALAMUS. The electrodes are attached to a neurostimulator placed subcutaneously.
Use of electric potential or currents to elicit biological responses.
Lens-shaped structure on the inner aspect of the INTERNAL CAPSULE. The SUBTHALAMIC NUCLEUS and pathways traversing this region are concerned with the integration of somatic motor function.
A procedure consisting of a sequence of algebraic formulas and/or logical steps to calculate or determine a given task.
Endoscopic examination, therapy or surgery of the bronchi.
The total volume of gas inspired or expired per unit of time, usually measured in liters per minute.
The outer covering of the calvaria. It is composed of several layers: SKIN; subcutaneous connective tissue; the occipitofrontal muscle which includes the tendinous galea aponeurotica; loose connective tissue; and the pericranium (the PERIOSTEUM of the SKULL).
A gland in males that surrounds the neck of the URINARY BLADDER and the URETHRA. It secretes a substance that liquefies coagulated semen. It is situated in the pelvic cavity behind the lower part of the PUBIC SYMPHYSIS, above the deep layer of the triangular ligament, and rests upon the RECTUM.
Complete or partial surgical removal of the prostate. Three primary approaches are commonly employed: suprapubic - removal through an incision above the pubis and through the urinary bladder; retropubic - as for suprapubic but without entering the urinary bladder; and transurethral (TRANSURETHRAL RESECTION OF PROSTATE).
Tumors or cancer of the PROSTATE.
The quantity of volume or surface area of a CELL NUCLEUS.

An intrinsic oscillation in interneurons of the rat lateral geniculate nucleus. (1/2193)

By using the whole cell patch recording technique in vitro, we examined the voltage-dependent firing patterns of 69 interneurons in the rat dorsal lateral geniculate nucleus (LGN). When held at a hyperpolarized membrane potential, all interneurons responded with a burst of action potentials. In 48 interneurons, larger current pulses produced a bursting oscillation. When relatively depolarized, some interneurons produced a tonic train of action potentials in response to a depolarizing current pulse. However, most interneurons produced only oscillations, regardless of polarization level. The oscillation was insensitive to the bath application of a combination of blockers to excitatory and inhibitory synaptic transmission, including 30 microM 6,7-dinitroquinoxaline-2,3-dione, 100 microM (+/-)-2-amino-5-phosphonopentanoic acid, 20 microM bicuculline, and 2 mM saclofen, suggesting an intrinsic event. The frequency of the oscillation in interneurons was dependent on the intensity of the injection current. Increasing current intensity increased the oscillation frequency. The maximal frequency of the oscillation was 5-15 Hz for most cells, with some ambiguity caused by the difficulty of precisely defining a transition from oscillatory to regular firing behavior. In contrast, the interneuron oscillation was little affected by preceding depolarizing and hyperpolarizing pulses. In addition to being elicited by depolarizing current injections, the oscillation could also be initiated by electrical stimulation of the optic tract when the interneurons were held at a depolarized membrane potential. This suggests that interneurons may be recruited into thalamic oscillations by synaptic inputs. These results indicate that interneurons may play a larger role in thalamic oscillations than was previously thought.  (+info)

Utilization of bioelectrical impedance to predict carcass composition of Holstein steers at 3, 6, 9, and 12 months of age. (2/2193)

The objective of this experiment was to study the usefulness of bioelectrical impedance analysis (BIA) in determining soft tissue composition (STC) and carcass fat-free mass (CFFM) of Holstein steers at different ages. Growth data and prediction of STC and CFFM were determined for four groups of Holstein steers: 12 of 3 mo, 12 of 6 mo, 15 of 9 mo, and 16 of 12 mo of age. Average weight for animals at 3, 6, 9, and 12 mo were 96.6, 204.7, 354.1, and 465.9 kg, respectively. Average fat content of carcass soft tissue at 3, 6, 9, and 12 mo were 2.6, 9.8, 18.2, and 24.6%, respectively. Average protein content of the carcass soft tissue was 20.7% at 3 mo, 20% at 6 mo, 18.30% at 9 mo, and 16.9% at 12 mo of age. Feed and water were withheld for 20 h before the BIA was applied. Steers were sedated and forced to recumbency in a lateral position on their right sides over a nonconductive surface. Two electrodes were placed on each limb of the right side (metatarsal and metacarpal regions on back and front foot, respectively). Resistance (Rs) and reactance (Xc) were obtained by attaching four terminals to the electrodes. Impedance and other predictors such as Vol1 (L/Rs), Vol2 (L2/(RS2+Xc2).5, Vol3 (geometrical animal volume), L (2 x height + body length), and L2 were calculated from Rs and Xc, and body measurements and were used to generate prediction equations for CFFM and carcass soft tissue composition. Carcass fat-free mass was predicted accurately for all age groups and the pooled data (r2 = .99 at 3 mo, .99 at 6 mo, .97 at 9 mo, .77 at 12 mo, and .98 for the pooled data). Correlation coefficients between impedance readings and CFFM and carcass composition were calculated. Carcass CFFM and kilograms of H2O for the pooled data (across age groups) were both correlated highly to Vol1 (.97), Vol2 (.95), L (.97), and L2 (.97).  (+info)

In vitro analog of operant conditioning in aplysia. I. Contingent reinforcement modifies the functional dynamics of an identified neuron. (3/2193)

Previously, an analog of operant conditioning in Aplysia was developed using the rhythmic motor activity in the isolated buccal ganglia. This analog expressed a key feature of operant conditioning, namely a selective enhancement in the occurrence of a designated motor pattern by contingent reinforcement. Different motor patterns generated by the buccal central pattern generator were induced by monotonic stimulation of a peripheral nerve (i.e., n.2,3). Phasic stimulation of the esophageal nerve (E n.) was used as an analog of reinforcement. The present study investigated the neuronal mechanisms associated with the genesis of different motor patterns and their modifications by contingent reinforcement. The genesis of different motor patterns was related to changes in the functional states of the pre-motor neuron B51. During rhythmic activity, B51 dynamically switched between inactive and active states. Bursting activity in B51 was associated with, and predicted, characteristic features of a specific motor pattern (i.e., pattern I). Contingent reinforcement of pattern I modified the dynamical properties of B51 by decreasing its resting conductance and threshold for eliciting plateau potentials and thus increased the occurrences of pattern I-related activity in B51. These modifications were not observed in preparations that received either noncontingent reinforcement (i.e., yoke control) or no reinforcement (i.e., control). These results suggest that a contingent reinforcement paradigm can regulate the dynamics of neuronal activity that is centrally programmed by the intrinsic cellular properties of neurons.  (+info)

Comparative cytotoxicity of ionic and non-ionic radiocontrast agents on MDCK cell monolayers in vitro. (4/2193)

BACKGROUND: Intravascular radiocontrast agents may cause acute renal failure, particularly in patients with pre-existing renal insufficiency. Direct cytotoxic effects of radiocontrast agents on renal tubular cells may contribute to the pathogenesis of radiocontrast-induced nephropathy. METHODS: We analysed the cytotoxicity of the ionic radiocontrast agents diatrizoate (monomeric) and ioxaglate (dimeric), as well as of the non-ionic radiocontrast agents iohexol (monomeric) and iodixanol (dimeric) on the renal epithelial Madin Darby Canine Kidney (MDCK) cell line grown on permeable supports. The toxicity assays assessed cell viability, transmonolayer resistance and inulin permeability between the apical and basal cell culture compartment. In addition, the distribution of the tight-junction-associated membrane proteins ZO-1 and occludin was analysed using immunofluorescence microscopy. RESULTS: In all assays the high osmolal ionic compound diatrizoate had significant cytotoxic effects that included the partial redistribution of the tight-junction-associated membrane proteins into a cytoplasmic compartment. To a lesser extent this redistribution also occurred with the dimeric ionic compound ioxaglate, but not with the non-ionic radiocontrast agents. With regards to cell viability, transmonolayer resistance and inulin permeability the radiocontrast agents with reduced osmolality were significantly less toxic than diatrizoate, independent of their ionic strength. CONCLUSIONS: Physicochemical factors contribute to the cytotoxicity of radiocontrast agents in vitro. The redistribution of tight-junction-associated membrane proteins by the ionic radiocontrast agents corresponds with the loss of the barrier function of the epithelial cell monolayer, which is a major pathophysiological mechanism in acute renal failure. The radiocontrast agents with reduced osmolality are less cytotoxic than diatrizoate, independent of their ionicity. Hyperosmolality appears to be a more important determinant of the cytotoxicity of diatrizoate than ionic strength.  (+info)

Fluid state and blood pressure control in patients treated with long and short haemodialysis. (5/2193)

BACKGROUND: Patients treated at the haemodialysis (HD) centre in Tassin, France have been reported to have superior survival and blood pressure (BP) control. This control has been ascribed to maintenance of an adequate fluid state, antihypertensive drugs being required in < 5% of the patients, although it could not be excluded that a high dose of HD regarding removal of uraemic toxins might also have been of value. METHODS: The aim of the study was to assess the fluid state and BP in normotensive patients on long HD (8 h) in Tassin (group TN) using bioimpedance to measure extracellular volume (ECV), ultrasound for determining the inferior vena cava diameter (IVCD), and 'on-line' monitoring of the change in blood volume (BV), and to compare them with normotensive (group SN) and hypertensive (group SH) patients on short HD (3-5 h) at centres in Sweden. ECV was normalized (ECVn) by arbitrarily setting the median ECV (in % of body weight) in SN patients at 100% for each gender, recalculating the individual values and combining the results for male and female patients in each group. RESULTS: The dose of HD (Kt/V urea) was higher for TN patients than for Swedish patients who had a similar Kt/V, whether hypertensive or not. SH patients had significantly higher ECVn and IVCD than TN and SN patients. TN and SN patients did not differ significantly regarding ECVn and IVCD before and after HD. However, in a subgroup of eight TN patients, ECVn was below the range of that in SH and SN patients, due to obesity with a high body mass index. Another subgroup of 14 TN patients had a higher ECVn than most of the SN patients and also higher than the median ECVn in the SH group, without any difference in body mass index, but they were nevertheless normotensive. The fall in BV was greater in SN than in TN patients, presumably due to a higher ultrafiltration rate in SN patients. However, SH patients had a smaller change in BV than SN patients, presumably because their state of overhydration facilitated refilling of BV from the interstitial fluid. CONCLUSIONS: Normotension can be achieved independently of the duration and dose (Kt/V urea) of HD, if the control of post-dialysis ECV is adequate. However, this is more difficult to achieve with short than with more prolonged HD during which the ultrafiltration rate is lower, BV changes are smaller and intradialysis symptoms less frequent. The results in the subgroup of patients with high ECVn at Tassin suggest that normotension may also be achieved in patients with fluid overload provided that the dialysis time is long enough to ensure more efficient removal of one or more vasoactive factors that cause or contribute to hypertension.  (+info)

Bioelectrical impedance plethysmographic analysis of body composition in critically injured and healthy subjects. (6/2193)

BACKGROUND: Determination of body composition during critical illness is complex because of various patient-related and technical factors. Bioelectrical impedance is a promising technique for the analysis of body composition; however, its clinical utility in critically injured patients is unknown. OBJECTIVE: The purpose of this study was to compare bioelectrical impedance with metabolic activity in healthy and critically injured patients. If bioelectrical impedance accurately determines body composition during critical illness, the slope between body-composition variables and oxygen consumption would be the same in critically injured and healthy subjects. DESIGN: There is a strong linear relation between body composition and metabolic activity. In the present study, body composition (fat-free mass and body cell mass) was determined by using bioelectrical impedance and resting metabolic activity (metabolic rate and oxygen consumption) by using gas exchange analysis in a group of healthy and critically injured subjects. The relation between these variables was compared by using linear regression to a similar relation established by hydrostatic weighing in a large historical control group. RESULTS: The slope of the line relating fat-free mass to resting metabolic rate was the same in the healthy and critically ill groups (P = 0.62) and each was similar to the slope of the line for the control group. However, in 37% of the critically injured group, overhydration contributed to an increase in fat-free mass, disturbing the relation with resting metabolic rate. The slope of the line relating body cell mass to oxygen consumption in our healthy and critically ill groups was almost identical. CONCLUSION: These results support the use of bioelectrical impedance to determine body cell mass in healthy and critically ill subjects.  (+info)

Relative influences of sex, race, environment, and HIV infection on body composition in adults. (7/2193)

BACKGROUND: The factors that control body composition in disease are uncertain. OBJECTIVE: We planned to compare the relative influences of HIV infection, sex, race, and environment on body composition. METHODS: We analyzed results of body composition studies performed by bioelectrical impedance analysis in 1415 adults from 2 cohorts: white and African American men and women from the United States, and African men and women (279 HIV-infected and 1136 control). The effects of sex and HIV infection on weight, body cell mass, and fat-free mass were analyzed by using both unadjusted and age-, weight-, and height-adjusted data. RESULTS: Control men weighed more and had more body cell mass and fat-free mass than did control women, although control women had more fat. The strongest correlates with body composition were height and weight, followed by sex. HIV infection, age, environment, and race. Control men and women weighed more and had more body cell mass, fat-free mass, and fat than did HIV-infected men. However, differences in body composition between HIV-infected and control groups were strongly influenced by sex. Of the differences in weight between HIV-infected and uninfected subjects, fat-free mass accounted for 51% in men but only 18% in women, in whom the remainder was fat. Sex effects were similar in African and American groups. CONCLUSIONS: Sex has a marked effect on the changes in body composition during HIV infection, with women losing disproportionately more fat than men. Sex-related differences in body composition were narrower in the HIV-infected groups. Race and environment had smaller effects than sex and HIV infection.  (+info)

The isoflavone genistein inhibits internalization of enteric bacteria by cultured Caco-2 and HT-29 enterocytes. (8/2193)

The dietary isoflavone genistein is the focus of much research involving its role as a potential therapeutic agent in a variety of diseases, including cancer and heart disease. However, there is recent evidence that dietary genistein may also have an inhibitory effect on extraintestinal invasion of enteric bacteria. To study the effects of genistein on bacterial adherence and internalization by confluent enterocytes, Caco-2 and HT-29 enterocytes (cultivated for 15-18 d and 21-24 d, respectively) were pretreated for 1 h with 0, 30, 100, or 300 micromol/L genistein, followed by 1-h incubation with pure cultures of Listeria monocytogenes, Salmonella typhimurium, Proteus mirabilis, or Escherichia coli. Pretreatment of Caco-2 and HT-29 enterocytes with genistein inhibited bacterial internalization in a dose-dependent manner (r = 0.60-0.79). Compared to untreated enterocytes, 1-h pretreatment with 300 micromol/L genistein was generally associated with decreased bacterial internalization (P < 0. 05) without a corresponding decrease in bacterial adherence. Using Caco-2 cell cultures, decreased bacterial internalization was associated with increased integrity of enterocyte tight junctions [measured by increased transepithelial electrical resistance (TEER)], with alterations in the distribution of enterocyte perijunctional actin filaments (visualized by fluorescein-labeled phalloidin), and with abrogation of the decreased TEER associated with S. typhimurium and E. coli incubation with the enterocytes (P < 0.01). Thus, genistein was associated with inhibition of enterocyte internalization of enteric bacteria by a mechanism that might be related to the integrity of the enterocyte tight junctions, suggesting that genistein might function as a barrier-sustaining agent, inhibiting extraintestinal invasion of enteric bacteria.  (+info)

Description of disease Bioelectric impedance analysis. Treatment Bioelectric impedance analysis. Symptoms and causes Bioelectric impedance analysis Prophylaxis Bioelectric impedance analysis
Purpose: To analyze the association between body fluid changes evaluated by bioelectrical impedance vector analysis and dilution techniques over a competitive season in athletes. Methods: A total of 58 athletes of both sexes (men: age 18.7 [4.0] y and women: age 19.2 [6.0] y) engaging in different sports were evaluated at the beginning (pre) and 6 months after (post) the competitive season. Deuterium dilution and bromide dilution were used as the criterion methods to assess total body water (TBW) and extracellular water (ECW), respectively; intracellular water (ICW) was calculated as TBW-ECW. Bioelectrical resistance and reactance were obtained with a phase-sensitive 50-kHz bioelectrical impedance analysis device; bioelectrical impedance vector analysis was applied. Dual-energy X-ray absorptiometry was used to assess fat mass and fat-free mass. The athletes were empirically classified considering TBW change (pre-post, increase or decrease) according to sex. Results: Significant mean vector ...
TY - JOUR. T1 - Bioelectrical impedance analysis. T2 - Implications for clinical practice. AU - Jacobs, Danny O.. PY - 1997/12/1. Y1 - 1997/12/1. N2 - Bioelectrical impedance analysis (BIA) has received significant attention as a means of studying body composition and the relationship of changes in the bodys conductive and other electrical properties to changes in body water or its distribution. The application of this technology to the care of patients with nutritional and metabolic disorders is presently under investigation. In this review, a broad overview of recent literature is provided, after the background and rationale for BIA and factors affecting the accuracy of measurements are reviewed.. AB - Bioelectrical impedance analysis (BIA) has received significant attention as a means of studying body composition and the relationship of changes in the bodys conductive and other electrical properties to changes in body water or its distribution. The application of this technology to the care ...
Drug and bioactive molecule screening based on a bioelectrical impedance cell culture platform Sakthivel Ramasamy,1 Devasier Bennet,1 Sanghyo Kim1,2 1Department of Bionanotechnology, Gachon University, Gyeonggi-Do, Republic of Korea; 2Graduate Gachon Medical Research Institute, Gil Medical Center, Incheon, Republic of Korea Abstract: This review will present a brief discussion on the recent advancements of bioelectrical impedance cell-based biosensors, especially the electric cell-substrate impedance sensing (ECIS) system for screening of various bioactive molecules. The different technical integrations of various chip types, working principles, measurement systems, and applications for drug targeting of molecules in cells are highlighted in this paper. Screening of bioactive molecules based on electric cell-substrate impedance sensing is a trial-and-error process toward the development of therapeutically active agents for drug discovery and therapeutics. In general, bioactive molecule
Bioelectrical Impedance Analysis (BIA) and Body Composition Analyse. Bioelectrical Impedance Analysis (BIA) and Body Composition Analyse.
Bioelectrical Impedance Analysis (BIA) and Body Composition Analyse. Bioelectrical Impedance Analysis (BIA) and Body Composition Analyse.
BACKGROUND: Little information is available on the validity of simple and indirect body-composition methods in non-Western populations. Equations for predicting body composition are population-specific, and body composition differs between blacks and whites. OBJECTIVE: We tested the hypothesis that the validity of equations for predicting total body water (TBW) from bioelectrical impedance analysis measurements is likely to depend on the racial background of the group from which the equations were derived. DESIGN: The hypothesis was tested by comparing, in 36 African women, TBW values measured by deuterium dilution with those predicted by 23 equations developed in white, African American, or African subjects. These cross-validations in our African sample were also compared, whenever possible, with results from other studies in black subjects. RESULTS: Errors in predicting TBW showed acceptable values (1.3-1.9 kg) in all cases, whereas a large range of bias (0.2-6.1 kg) was observed ind
This thesis work covered the fabrication and characterisation of impedance sensors for biological applications aiming in particular to the cytotoxicity monitoring of cultured cells exposed to different kind of chemical compounds and drugs and to the identification of different types of biological tissue (fat, muscles, nerves) using a sensor fabricated on the tip of a commercially available needle during peripheral nerve block procedures. Gold impedance electrodes have been successfully fabricated for impedance measurement on cells cultured on the electrode surface which was modified with the fabrication of gold nanopillars. These nanostructures have a height of 60nm or 100nm and they have highly ordered layout as they are fabricated through the e-beam technique. The fabrication of the threedimensional structures on the interdigitated electrodes was supposed to improve the sensitivity of the ECIS (electric cell-substrate impedance sensing) measurement while monitoring the cytotoxicity effects of ...
Arias L.R., Carla A.P., Yang L.: Real-Time Electrical Impedance Detection of Cellular Activities of Oral Cancer Cells. Biosensors and Bioelectronics 25(10), 2010, 2225-2231. DOI: https://doi.org/10.1016/j.bios.2010.02.029 Arndt S., Seebach J., Psathaki K., Galla H.J., Wegener J.: Bioelectrical Impedance Assay to Monitor Changes in Cell Shape during Apoptosis. Biosensors and Bioelectronics 19(6), 2004, 583-594. DOI: https://doi.org/10.1016/S0956-5663(03)00269-0 Bagnaninchi P.O., Drummond N.: Real-Time Label-Free Monitoring of Adipose-Derived Stem Cell Differentiation with Electric Cell-Substrate Impedance Sensing. Proceedings of the National Academy of Sciences of the United States of America 108(16), 2011, 6462-6467. DOI: https://doi.org/10.1073/pnas.1018260108 Giaever I., Keese C.R.: A Morphological Biosensor for Mammalian Cells. Nature 366(6455), 1993, 591-592. Hong J., Kandasamy K., Marimuthu M., Choi M.S., Kim S.: Electrical Cell-Substrate Impedance Sensing as a Non-Invasive Tool for Cancer ...
Background: Appendicular skeletal muscle (or lean) mass (ALM) estimated by dual-energy X-ray absorptiometry (DXA) is considered to be a preferred method for sarcopenia studies. However, DXA is expensive, has limited portability, and requires radiation exposure. Bioelectrical impedance analysis (BIA) is inexpensive, easy to use, and portable; thus BIA might be useful in sarcopenia investigations. However, a large variety of models have been commercially supplied by different companies, and for most consumer products, the equations estimating ALM are not disclosed. It is therefore difficult to use these equations for research purposes. In particular, the BIA equation is often age-dependent, which leads to fundamental difficulty in examining age-related ALM loss. The aims of the current study were: 1) to develop and validate an equation to estimate ALM using multi-frequency BIA (MF-BIA) using theoretical models, and 2) to establish sarcopenia cutoff values using the equation for the Japanese
Electric impedance tomography market is expected to gain market growth in the forecast period of 2020 to 2027. Data Bridge Market Research analyses the market to growing at a CAGR of 8.8% in the above-mentioned forecast period. Technological advancements and the rising prevalence of breast cancer are acting as the o...
TY - JOUR. T1 - Body composition in renal transplant patients: bioimpedance analysis compared to isotope dilution, dual energy X-ray absorptiometry, and anthropometry.. AU - van den Ham, E.C.H.. AU - Kooman, J.P.. AU - Christiaans, M.H.. AU - Nieman, F.H.M.. AU - van Kreel, B.K.. AU - Heidendal, G.A.K.. AU - van Hooff, J.P.. PY - 1999/1/1. Y1 - 1999/1/1. N2 - Department of Internal Medicine, University Hospital Maastricht, The Netherlands. [email protected] multifrequency bioelectrical impedance analysis (MF-BIA), a relatively new method for measuring body composition, is also applicable for accurate body composition measurements in renal transplant (RTx) patients is not known. Therefore, the use of MF-BIA is validated in 77 RTx patients with a stable renal function at least 2 yr posttransplantation. MF-BIA is compared to isotope dilution techniques for measurement of body water compartments, and to dual energy x-ray absorptiometry (DEXA) and anthropometry for measurement of ...
Bioelectrical impedance analysis (BIA) is a commonly used method for estimating body composition, and in particular body fat. Since the advent of the first commercially available devices in the mid-1980s the method has become popular owing to its ease of use, portability of the equipment. It is familiar in the consumer market as a simple instrument for estimating body fat. BIA actually determines the electrical impedance, or opposition to the flow of an electric current through body tissues which can then be used to estimate total body water (TBW), which can be used to estimate fat-free body mass and, by difference with body weight, body fat. Many of the early research studies showed that BIA was quite variable and it was not regarded by many as providing an accurate measure of body composition. In recent years technological improvements have made BIA a more reliable and therefore more acceptable way of measuring body composition. Nevertheless, it is not a gold standard or reference method. ...
In 20 mechanically ventilated patients who routinely undergo bronchoscopy Electrical Impedance Tomography (EIT) measurements whereby, evaluable data of 10 patients are needed, of about 1-2 minutes are performed directly before, directly after and 10, 30, and 60 minutes after bronchoscopy parallel to the following routine measurements: tidal volume, resistance, compliance, heart rate, blood pressure, SpO2 and blood gas values. Prior to the examination a rubber belt with 16 integrated electrocardiographic electrodes is placed around the thorax connected with an EIT- device. EIT data are generated by application of a small alternating current of 5mA and 50kHz and are stored and analyzed offline on a personal computer. The EIT provides a mapping of the distribution of the lung´s electrical impedance and exhibits a far temporal resolution of up to 40 tomograms per second. Because of electrical impedance of the pulmonal tissue is dependant to the air content, the air distribution within the lung over ...
Background: Roux-en-Y gastric bypass (RYGB) result in a marked reduction of body fat and also visceral fat (VF) decrease up to 36 % in 16 weeks. This leads to positive effects on cardiometabolic risks, which are known to be correlated with the occurrence of VF. This study analyzed the validity of bioelectrical impedance analysis (BIA) for determining VF in the postoperative course. In addition, magnetic resonance imaging (MRI) was performed for prediction of whole VF in bariatric patients on the basis of a single slice. Methods: Eighteen patients, who underwent RYGB (18), were included in this study. MRI and BIA measurements were performed 1 day before surgery, as well as 6, 12, and 24 weeks after surgery. Results: During the postoperative observation period, we found a significant decrease of both subcutaneous fat (SF) and VF. SF measured by MRI was highly correlated with the level of body fat shown by BIA. In contrast, the VF volume, as determined by MRI, showed no correlation with the body ...
Electrical bioimpedance measurement is widely used today for monitoring body condition. The applications include and go beyond, body composition assessment, nutritional status evaluation, and cancer detection. The modalities for interpreting the impedance information have also developed quickly over the recent decades from single frequency bioimpedance analysis to spectrum and to images.. Bioimpedance is measured by computing the relationship between voltage and current. In a current based bioimpedance measurement system, the stability of current source has a large influence on the performance of the system. This thesis compared three different voltage controlled current sources: enhanced Howland circuit, load-in-the-loop circuit driven by a current conveyor and double operational amplifiers circuit. These circuits were simulated in Multisim and manufactured into prototypes and tested in lab.. Effort has also been made to generate and collect signals with digital-to-analog convertor and ...
VAL104. Belarmino G,Gonzalez MC,Torrinhas RS,Sala P,Andraus W,Carneiro DAlbuquerque LA,Pereira RMR,Caparbo VF,Ravacci GR,Damiani L,Heymsfield SB,Waitzberg DL. World J Hepatol 2017 March 8; 9(7): 401-408. Background: To evaluate the prognostic value of the phase angle (PA) obtained from bioelectrical impedance analysis (BIA) for mortality prediction in patients with cirrhosis.. Subjects /Methods: In total, 134 male cirrhotic patients prospectively completed clinical evaluations and nutritional assessment by BIA to obtain PAs during a 36-mo follow-up period. Mortality risk was analyzed by applying the PA cutoff point recently proposed as a malnutrition marker (PA≤ 4.9°) in Kaplan-Meier curves and multivariate Cox regression models.. Results: The patients were divided into two groups according to the PA cutoff value (PA , 4.9°, n = 73; PA ≤ 4.9°, n = 61). Weight, height, and body mass index were similar in both groups, but patients with PAs , 4.9° were younger and had higher mid-arm muscle ...
TY - JOUR. T1 - Changes in biphasic electrode impedance with protein adsorption and cell growth. AU - Newbold, Carrie. AU - Richardson, Rachael. AU - Millard, Rodney. AU - Huang, Christie. AU - Milojevic, Dusan. AU - Shepherd, Robert. AU - Cowan, Robert. PY - 2010/10. Y1 - 2010/10. N2 - This study was undertaken to assess the contribution of protein adsorption and cell growth to increases in electrode impedance that occur immediately following implantation of cochlear implant electrodes and other neural stimulation devices. An in vitro model of the electrode-tissue interface was used. Radiolabelled albumin in phosphate buffered saline was added to planar gold electrodes and electrode impedance measured using a charge-balanced biphasic current pulse. The polarization impedance component increased with protein adsorption, while no change to access resistance was observed. The maximum level of protein adsorbed was measured at 0.5 μg cm-2, indicating a tightly packed monolayer of albumin molecules ...
Accurate measurement of body fat mass (BFM) is critical in assessing overweight and obesity that pause health implications of other non-communicable diseases (NCDs). The traditional commonly used method, body mass index (BMI) is not adequate to measure BFM because it does not account for body composition. Hence the study measured BFM and free fat mass (FFM) using bioelectrical impedance analysis (BIA) in relation to BMI. This allowed for better estimation of human nutritional status and determination of misclassification when BMI method is used alone. A total of 247 participants, comprising 54% females and 46%males aged 18-55 years were selected from University of Zambia (UNZA), Chalimbana University (CHAU), Natural Resources Development College (NRDC) and Chongwe College of Education (CCE). Participants were further categorized into young adults aged 18-39 years (77%) and old adults aged 40-55 years (23%). Both measurements of BMI and BIA were taken in the morning following overnight fasting ...
The assessment of body composition has important applications in the evaluation of nutritional status and estimating potential health risks. Bioelectrical impedance analysis (BIA) is a valid method for the assessment of body composition. BIA is an alternative to more invasive and expensive methods l …
Application of bioelectrical impedance analysis and anthropometry as interchangeable methods to assess body composition of sportspersons.
0073]1A, 1B, 1C, 1D body fat measurement device [0074]10 control unit [0075]11 calculation processing section [0076]12 impedance measuring portion [0077]13 body fat mass calculating portion [0078]14 total fat mass calculating part [0079]15 site type fat mass calculating part [0080]16 visceral fat mass calculating part [0081]17 subcutaneous fat mass calculating part [0082]18 breathing state detecting portion [0083]21 constant current generation unit [0084]22 terminal switching unit [0085]23 potential difference detection unit [0086]24 physical information measurement unit [0087]25 subject information input unit [0088]26 display unit [0089]27 operation unit [0090]28 power supply unit [0091]29 memory [0092]30 body peripheral length measurement unit [0093]100A, 100A1, 100A2, 100B, 100C, 100D, 100D1 impedance measurement abdomen attachment unit [0094]101 device main body [0095]110A, 110A1, 110D, 110D1 abdomen rear surface side base portion [0096]112 support base [0097]112a one end [0098]112b other ...
Quantifying cell growth is essential for many applications in cell biology and biotechnology. It is required for optimizing cell culture conditions, for studying substances that inhibit or promote cell growth, for studying cancer progression, cytotoxicity assessment, biocompatibility characterization, etc. Traditional cell proliferation assays are label-based endpoint assays that require sample preparation and sophisticated lab equipment. An example of an alternative, label-free technique that is being currently employed for automating cell proliferation studies is electric cell-substrate impedance sending (ECIS). However, ECIS still requires external measurement instruments such as lock-in amplifiers and impedance analyzers. Researchers at the University of Maryland have developed a novel miniaturized technique in which CMOS capacitance sensors are employed to measure the capacitive coupling between on-chip sensing electrodes and the cellular matrix cultured on them, as a means of tracking cell ...
TY - JOUR. T1 - Application of ECIS to assess FCCP-induced changes of MSC micromotion and wound healing migration. AU - Chiu, Sheng Po. AU - Lee, Yu Wei. AU - Wu, Ling Yi. AU - Tung, Tse Hua. AU - Gomez, Sofia. AU - Lo, Chun Min. AU - Wang, Jia Yi. N1 - Funding Information: This work was partially supported by grants from the Tri-Service General Hospital Songshan Branch (grant number 10808) and from the Ministry of Science and Technology of the Republic of China, Taiwan (grant number MOST-102-2628-B-010-010-MY3). Funding Information: Funding: This work was partially supported by grants from the Tri-Service General Hospital Songshan Branch (grant number 10808) and from the Ministry of Science and Technology of the Republic of China, Taiwan (grant number MOST-102-2628-B-010-010-MY3). Publisher Copyright: © 2019 by the authors. Licensee MDPI, Basel, Switzerland.. PY - 2019/7/2. Y1 - 2019/7/2. N2 - Electric cell-substrate impedance sensing (ECIS) is an emerging technique for sensitively monitoring ...
Linköping University, Department of Clinical and Experimental Medicine, Burn Center. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Department of Plastic Surgery, Hand surgery UHL. Östergötlands Läns Landsting, Sinnescentrum, Department of Anaesthesiology and Surgery UHL. ...
TY - JOUR. T1 - Bioelectrical impedance analysis-derived phase angle at admission as a predictor of 90-day mortality in intensive care patients. AU - Stapel, Sandra N. AU - Looijaard, Wilhelmus G P M. AU - Dekker, Ingeborg M. AU - Girbes, Armand R J. AU - Weijs, Peter J M. AU - Oudemans-van Straaten, Heleen M. PY - 2018/7. Y1 - 2018/7. N2 - BACKGROUND/OBJECTIVES: A low bioelectrical impedance analysis (BIA)-derived phase angle (PA) predicts morbidity and mortality in different patient groups. An association between PA and long-term mortality in ICU patients has not been demonstrated before. The purpose of the present study was to determine whether PA on ICU admission independently predicts 90-day mortality.SUBJECTS/ METHODS: This prospective observational study was performed in a mixed university ICU. BIA was performed in 196 patients within 24 h of ICU admission. To test the independent association between PA and 90-day mortality, logistic regression analysis was performed using the APACHE IV ...
The analysis of electrical signals originating from biological cells and tissues have yielded a large amount of useful information over the past years. Technologies have been developed, wherein we can monitor the health of the biological material of interest using these electrical signals. Instruments for the study of living cells have historically been of significant importance for such things as basic neuroscience, cell biology, pharmaceutical screening, environmental monitoring, and toxin detection. One of the practical realizations of these methods was successfully implemented by Giaver and Keese with their Electric Cell-Substrate Impedance Sensing (ECIS) system. The purpose of this Masters Thesis is to showcase the use of a Cellular Impedance Biosensor setup based on the ECIS system in real-time monitoring of endothelial barrier function and quantify the dynamic changes of the cytoskeleton filaments induced by different drugs. The filaments of the endothelial cell cytoskeleton play a ...
A simple and very accurate method for measuring the viscosity of liquids is presented. A vibrating lead zirconate titanate (PZT) ceramic polycrystalline resonator is totally immersed in a liquid and the oscillation behavior is studied both analytically and experimentally. The vibrating ceramic generates a shear wave traveling in the surrounding fluid normal to the surface of the resonator with heavy damping. The PZT is modeled as a vibrating thin plate. The resulting one-dimensional governing equation of motion, which includes the effect of damping, is solved with the appropriate damped boundary conditions using impedance methods. The resonance frequency of a PZT immersed in a fluid is shown to be a function of the PZT parameters and the product of the fluid density and viscosity. Fluid loading is shown to lower the resonance frequency of the ceramic and both diminish and broaden the impedance plot near resonance. Unlike previous methods utilizing crystal shear-mode resonators, this method is ...
More soldiers become ill or injured from disease and non-battle injuries than from combat, and providing good quality water supplies to the warfighter is a key element in preventing such injuries. Basic field water tests can detect only a few high priority threat chemicals, and comprehensive testing for additional chemicals can takes days or weeks. The ESB provides rapid toxicity identification for many industrial and agricultural chemicals in water. Rather than evaluating individual chemical constituents, the ESB system uses two individual biological-based sensors to identify toxic responses associated with the presence of chemicals: an electric cell-substrate impedance sensing (ECIS) device that measures changes electrical characteristics of a layer of vertebrate cells grown on fluidic biochips, and a pesticide sensor (also known as the ACE™ Rapid Test for Acetylcholinesterase Inhibitors, or ACE™ sensor) that measures enzyme inhibition caused primarily by carbamate and organophosphorus ...
Interelectrode impedance or electric field potential measurements are used to determine the relative orientation of one lead to other leads in the spinal column or other body/tissue location. Interelectrode impedance is determined by measuring impedance vectors. The value of the impedance vector is due primarily to the electrode-electrolyte interface, and the bulk impedance between the electrodes. The bulk impedance between the electrodes is, in turn, made up of (1) the impedance of the tissue adjacent to the electrodes, and (2) the impedance of the tissue between the electrodes. In one embodiment, the present invention makes both monopolar and bipolar impedance measurements, and then corrects the bipolar impedance measurements using the monopolar measurements to eliminate the effect of the impedance of the tissue adjacent the electrodes. The orientation and position of the leads may be inferred from the relative minima of the corrected bipolar impedance values. These corrected impedance values may also
Using a recombinant mini-laminin-332, we showed that truncation of the three C-terminal amino acids of the gamma 2 chain, but not of the C-terminal amino acid of the 133 chain, completely abolished alpha 3 beta 1 integrin binding and its cellular functions, such as attachment and spreading. However, a synthetic peptide mimicking the gamma 2 chain C-terminus did not interfere with 0 l integrin binding or cell adhesion and spreading on laminin-332 as measured by protein interaction assays and electric cell-substrate impedance sensing. Nor was the soluble peptide able to restore the loss of integrin-mediated cell adhesiveness to mini-laminin-332 after deletion of the gamma 2 chain C-terminus. These findings spoke against the hypothesis that the gamma 2 chain C-terminus of laminin-332 is a part of the 0[ l integrin interaction site. in addition, structural studies with electron microscopy showed that truncation of the gamma 2 chain C-terminus opened up the compact supradomain structure of LG1-3 ...
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In this study, the bioelectrical impedance analysis (BIA), skinfold thickness measurement (STM) and dual-energy X-ray absorptiometry (DXA), as a reference method, were compared with each other in the assessment of body composition in elderly (62-72-year-old) Finnish women (n=93). BIA had better agreement with DXA in the assessment of fat free mass (FFM, R2=0.70, Sres=2.1) and fat mass (FM, R2=0.93, Sres=2.3) than the STM (FFM, R2=0.62, Sres=2.4; FM, R2=0.89,Sres=2.8). There was quite a large variation in the estimates when different BIA prediction equations were used. The equation developed in this study, FFM (kg)=-128.06 + 1.85 x BMI-0.63 x weight + 1.07 x height - 0.03 x resistance +10.0 x waist-hip ratio, yielded a small and unbiased error (0.5 +/- 1.6 kg), with a small residual standard deviation (R2=0.83, Sres=1.6). However, error associated with the estimate of FM was positively related to the degree of FM. BIA(Heitmann) equation yielded unbiased estimates of both FFM and FM (FFM, R2=0.77, ...
Use of multifrequency bioelectrical impedance analysis for estimation of total body water and extracellular and intracellular fluid volumes in horses ...
SUNNYVALE, CA - November 17, 2008 - MDS Analytical Technologies, a leader in innovative solutions for drug-discovery and life-sciences research, today announced the delivery of the first three CellKeyTM384 Systems, the worlds first impedance-based, label-free, high-throughput instrument for use in drug-discovery research. Additional systems are scheduled to be delivered before the close of the calendar year.
TY - JOUR. T1 - Total body fat and the risk of Barretts oesophagus - A bioelectrical impedance study. AU - Kendall, Bradley J. AU - Macdonald, Graeme. AU - Prins, Johannes. AU - OBrien, Suzanne. AU - Whiteman, David. AU - Green, Adele. AU - Hayward, Nicholas. AU - Parsons, Peter. AU - Pavey, Sandra. AU - Purdie, David. AU - Webb, Penelope. AU - Gotley, David. AU - Smithers, B. AU - Jamieson, Glyn. AU - Drew, Paul. AU - Watson, David. AU - Clouston, Andrew. PY - 2014. Y1 - 2014. N2 - Background: Body mass index is associated with the risk of Barretts oesophagus (BO). It is uncertain whether this is related to total body fat or other factors that correlate with body mass index. We aimed to quantify the association between total body fat (measured by bioelectrical impedance) and risk of BO and examine if this association was modified by gastro-oesophageal reflux (GOR) and abdominal obesity. Methods: In 2007-2009, we surveyed 235 cases (69% Males, Mean age 62.1 years) and 244 age and sex matched ...
This handbook introduces the basics of impedance measurements using Keysights LCR meters and impedance analyzers. Learn some great impedance measurement techniques!
Two hundred and fifty seven male Caucasian ultra endurance athletes were recruited, pre-race, before different swimming, cycling, running and triathlon races. Fat mass and skeletal muscle mass were estimated using bioelectrical impedance analysis (BIA) and anthropometric methods in order to investigate whether the use of BIA or anthropometry would be useful under field conditions. Total body fat estimated using BIA was significantly high (P , 0.001) compared with anthropometry. When the results between BIA and anthropometry were compared, moderate to low levels of agreement were found. These results were in accordance with the differences found in the Bland-Altman analysis, indicating that the anthropometric equation of Ball et al. had the highest level of agreement (Bias = -3.0 ± 5.8 kg) with BIA, using Stewart et al. (Bias = -6.4 ± 6.3 kg), Faulkner (Bias = -4.7 ± 5.8 kg)and Wilmore-Siri (Bias = -4.8 ± 6.2 kg). The estimation of skeletal muscle mass using BIA was significantly (P , 0.001) ...
RFS5005A is a development platform for Electrical Impedance Tomography systems. It allows to use single RCL bridge or Impedance analyzer and switch its terminals between up to 16 electrodes. The design ensures low crosstalk and fast switching times. The RFS5005A contains: RFS5003B T-switch multiplexer board, linear- regulated power supply (+5V; -5V; +15V; -15V) and a universal metal rack 19
TY - JOUR. T1 - Identification of the human electrical impedance indifferent point. T2 - A surrogate for the volume indifferent point?. AU - Jarvis, Sara S.. AU - Pawelczyk, James A.. PY - 2009/8/12. Y1 - 2009/8/12. N2 - Head-up tilt (HUT) redistributes ∼700 mL of blood to the dependent regions. In a gravitational field, hydrostatic pressure is balanced against vascular compliance, resulting in a hydrostatic indifferent point (HIP) whose location should be coincident with an indifferent point for volume (VIP). Cardiac filling is determined by the hydrostatic gradient between the HIP/VIP and right atrium. We employed segmental impedance to examine blood volume redistribution during HUT and estimate the location of the VIP. During HUT, impedance increased in the chest and decreased in the lower abdomen, presumably due to blood volume shifts. Using a non-linear model to relate blood volume shifts to the hydrostatic gradient, we estimated the location of the electrical impedance indifferent point ...
Non-invasive single cell analyses are increasingly required for the medicaldiagnostics of test substances or the development of drugs and therapies on the single celllevel. For the non-invasive characterisation of cells, impedance spectroscopy whichprovides the frequency dependent electrical properties has been used. Recently,microfludic systems have been investigated to manipulate the single cells and tocharacterise the electrical properties of embedded cells. In this article, the impedance ofpartially embedded single cells dependent on the cellular behaviour was investigated byusing the microcapillary. An analytical equation was derived to relate the impedance ofembedded cells with respect to the morphological and physiological change ofextracellular interface. The capillary system with impedance measurement showed afeasibility to monitor the impedance change of embedded single cells caused bymorphological and physiological change of cell during the addition of DMSO. By fittingthe derived equation to
The ultra-wideband impedance sensor (UWBZ sensor, or Z-sensor) is implemented in differential and single-ended configurations. The differential UWBZ sensor employs a sub-nanosecond impulse to determine the balance of an impedance bridge. The bridge is configured as a differential sample-and-hold circuit that has a reference impedance side and an unknown impedance side. The unknown impedance side includes a short transmission line whose impedance is a function of the near proximity of objects. The single-ended UWBZ sensor eliminates the reference side of the bridge and is formed of a sample and hold circuit having a transmission line whose impedance is a function of the near proximity of objects. The sensing range of the transmission line is bounded by the two-way travel time of the impulse, thereby eliminating spurious Doppler modes from large distant objects that would occur in a microwave CW impedance bridge. Thus, the UWBZ sensor is a range-gated proximity sensor. The Z-sensor senses the near
La tunisie medicale : Article medicale COPD patients body composition and its impact on lung function par Meriem Mjid , Houda Snène , Abir Hedhli , Sana Cheikh Rouhou , Sonia Toujani , Besma Dhahri
Experimental setup. (a) Interface impedance measurement (schematic of impedance measurement (left), fabricated MEA on PCB (right)); (b) Charge injection limit m
A portable bioelectric impedance monitor for monitoring extracellular fluid levels includes a tetrapolar electrode array lead with four electrodes arranged sequentially and axially along the lead, and circuitry coupled with the at least four electrodes configured to measure bioelectric impedance extracellular fluid in a human subject at a frequency of less than 15 kHz. The electrodes are adhered to a human subject/patient on the patients torso or one of the patients limbs. One embodiment includes a Tetrapolar Analog Front End Patient Interface circuit configured to convert two electrode operation of a commercial Impedance Converter, Network Analyzer into a tetrapolar operation for excitation and impedance measurement of the human subject.
TY - JOUR. T1 - Myocardial electrical impedance responds to ischemia and reperfusion in humans. AU - Dzwonczyk, Roger. AU - Del Rio, C.. AU - Brown, D. A.. AU - Michler, R. E.. AU - Wolf, R. K.. AU - Howie, M. B.. PY - 2002/12/1. Y1 - 2002/12/1. N2 - Myocardial electrical impedance (MEI) is correlated to ischemia and reperfusion of the heart muscle. The entire body of work with MEI to this point has been carried out in nonhuman animal subjects and excised tissue samples. In this study we measured MEI clinically for the first time in human patients who were undergoing off-pump coronary artery bypass (OPCAB) surgery. Our patient population had a 70-100% stenosis of the coronary artery targeted for bypass. We measured MEI continuously during surgery and at 3, 6, 24 and 72hrs postop from two temporary pacing electrodes attached to heart. MEI increased with occlusion of the diseased artery prior to bypass. The percent increase from baseline was correlated to the percent stenosis of the artery. MEI ...
Electrical properties of food materials can give information about the inner structure and physiological state of biological tissues. Generally, the process of drying of fruits and vegetables is followed by weight loss. The aim of this study was to measure the impedance spectra of carrot slices during drying and to correlate impedance parameters to moisture content in different drying periods. Cylindrical slices were cut out from the carrot root along the axis. The slices were dried in a Venticell 111 air oven at 50°C. The weight of the slices was measured with a DenverSI-603 electronic analytical and precision balance. The weighing of the samples was performed every 30 min at the beginning of drying and every 60 min after the process. The moisture content of the samples was calculated on wet basis. The magnitude and phase angle of electrical impedance of the slices were mea-sured with HP 4284A and 4285A precision LCR meters in thefrequency range from 30 Hz to 1 MHz and from 75 kHz to 30 ...
BIOPAC Biopotential Amplifiers are specialized differential amplifiers designed to amplify the uV and mV level biopotentials that are generated by living organisms. Biopotentials are electrical signals (voltages) that are generated by physiological processes occurring within the body. Biopotentials are produced by the electrochemical activity of a type of cell, called an excitable cell. Excitable cells are found in the nervous, muscular and glandular systems in the body. When an excitable cell is stimulated, it generates an action potential, which is the essential source of biopotentials in the body. The body sources other biopotentials that are not directly related to action potentials. Examples include the corneal-retinal (corneoretinal) potential, skin potential and the electromechanical behavior of bone. In addition, many physiological processes in the body contribute to measurable impedance changes. Impedance changes are sensed by applying external excitation signals that convert impedance ...
In children 8-12 years old, BMI gives a good estimation of the total body fat as measured on MRI. The estimation will be improved when both BEI and BMI are used in the prediction. Bioelectrical impedance has a low correlation with total body fat and its use alone in estimating total body fat is not …
High-frequency digital sign processors suffer from electro-magnetic disturbance, because of its ever-increasing integration procedure and level acceleration. can be proportional to range can be inversely proportional to range and C inversely. Therefore, simplified equivalence, as well as the impedance can be depicted in Fig.?3. Fig.?3 Comparative circuit magic size As is demonstrated in Fig.?4, to be able to determine guidelines from the circuit, means the exterior impedance from the source, for the same internal current way to obtain the LSI/IC under measurement, as well as for the same internal impedance of these devices under measured. These devices internal impedance could be assessed by an impedance analyser, as can be proven in Fig.?5. The resonance frequency could be observed through the impedance diagram then. The resulting guidelines (and with an impedance analyser The exterior circuit current could KW-2449 be assessed by a range analyser as well as the particular sketch can be ...
Electrical impedance tomography (EIT) maps out the electrical conductivity of the ground using a two-dimensional grid of ... "Electrical impedance tomography". Cite journal requires ,journal= (help) In MacDonald & Lockwood 2003, pp. 161-168. McFee, J. E ... "Acoustic compliance, inertance and impedance". Physclips. University of New South Wales. Retrieved 3 April 2019. Phillips, ... and the resulting changes in electric potential can be used to detect metal objects. Similar devices are used by hobbyists. ...
Low-impedance electric discharge device. U.S. Patent No. 1,629,009. System for converting sound waves into electrical waves. U. ... 17 May 1927). Low-impedance electric discharge device. U.S. Patent No. 1,629,009.Washington, DC: U.S. Patent and Trademark ... Electrical cut-out. U.S. Patent No. 1,480,225. Oscillation generator. U.S. Patent No. 1,579,895. Electric ignition system. U.S ... His present occupation was electrical engineer and employed by the Western Electric Co. located at 463 West Street in New York ...
The impedance can be measured from difference in amplitude. The impedance has two components: electrical conductivity and ... This method measures the electrical impedance. Electromagnetic waves traveling along Transmission Lines (TL) enter in soil ... medium whose impedance is different from TL a part of the energy is reflected back to transmitter. The reflected wave ...
Electrical Impedance of Suspensions of Spheres. Journal of General Physiology PMID 19872446 Cole, K.S. 1979. Mostly membranes. ... The impedance Z {\displaystyle Z} is given by: Z = R ∞ + R 0 − R ∞ 1 + ( j f f c ) 1 − α {\displaystyle Z=R_{\infty }+{\frac {R ... His studies of electrical resistance in nerve cells, especially those of squid, laid the foundation for the rapid advance of ... Kenneth S. Cole, winner of the National Medal of Science and a pioneer in the study of the electrical properties of nerves and ...
Magnetic impedance is analogous to electrical impedance. Magnetic complex impedance (SI unit: Ω−1) is determined by: Z M = F Φ ... Model elements in the magnetic circuit that represent electrical elements are typically the electrical dual of the electrical ... A magnetic inductor can represent an electrical capacitor. A shunt capacitance in the electrical circuit, such as intra-winding ... Complex magnetic impedance can be presented in following form: Z M = z M e j ϕ = z M cos ⁡ ϕ + j z M sin ⁡ ϕ = r M + j x M {\ ...
Electrical impedance tomography, Adam Hilger, Bristol, England, 1990. Webster, J. G. (ed.), Teaching design in electrical ... He first proposed the idea of electrical impedance tomography as a medical imaging technique in a publication in 1978. In his ... of Electrical Eng., Univ. of Wisconsin-Madison 1976-80 Director of Biomedical Eng. Ctr., Univ. of Wisconsin-Madison 1973-1999 ... John G. Webster is an American electrical engineer and a founding pioneer in the field of biomedical engineering. In 2008, ...
... is a passive electrical component described by its electrical impedance, Z. The impedance can be broken up into ... Copper conductor Electrical impedance Loudspeaker enclosure Psychoacoustics "Auxiliary Loudspeaker". Popular Science. Bonnier ... As speaker impedance drops, lower gauge (heavier) wire is needed to prevent degradation to damping factor - a measure of the ... A speaker wire's impedance takes into account the wire's resistance, the wire's path, and the dielectric properties of local ...
Cole KS, Curtis HJ (May 1939). "Electric Impedance of the Squid Giant Axon During Activity". The Journal of General Physiology ... Electric Biology, the study of the electrical processes in the organism represented on a modern basis]. Braunschweig: Vieweg ... The electrical properties of a cell are determined by the structure of the membrane that surrounds it. A cell membrane consists ... Even the electrical activity of the cell itself may play a role in channel expression. If action potentials in Xenopus myocytes ...
This is the mathematical formulation of electrical impedance tomography. The solution of partial differential equation in an ... tangential electric field on the boundary of a region to the equivalent electric current on its boundary. Fluid-structure ...
Cole KS (1939). "Electrical impedance of the squid giant axon during activity". J. Gen. Physiol. 22 (5): 649-670. doi:10.1085/ ... Hodgkin and Andrew Huxley later presented a mathematical model for transmission of electrical signals in neurons of the giant ... Richard Caton presented his findings in 1875 about electrical phenomena of the cerebral hemispheres of rabbits and monkeys. In ... The hypotheses of the neuron doctrine were supported by experiments following Galvani's pioneering work in the electrical ...
Electrical termination Electrical impedance Grid resistor Kleinschmidt, Kirk, ed. (1990). ARRL Handbook for the Radio Amateur. ... Load banks are connected to electrical power supplies to simulate the supply's intended electrical load for testing purposes. ... A dummy load is a device used to simulate an electrical load, usually for testing purposes. In radio a dummy antenna is ... The dummy load ordinarily should be a pure resistance; the amount of resistance should be the same as the impedance of the ...
The other is bioelectrical impedance analysis which uses electrical resistance. Bioelectrical impedance has not been shown to ...
Ringing can be due to signal reflection, in which case it may be minimized by impedance matching. In video circuits, electrical ... Microphonics Ripple (electrical) Impedance matching Oxford English Dictionary (2nd ed.). Oxford University Press. 1989. f. The ... In electrical circuits, ringing is an unwanted oscillation of a voltage or current. It happens when an electrical pulse causes ...
Modern SDRAM chips exemplify the problem of electrical impedance discontinuity.[clarification needed] Fully Buffered DIMM is an ... A multidrop bus (MDB) is a computer bus in which all components are connected to the electrical circuit. A process of ... Multidrop buses have the advantage of simplicity and extensibility, but their differing electrical characteristics make them ...
The negative impedance converter is an example of such a circuit. Reactance is the imaginary part of the complex electrical ... 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 ( ... This is sometimes referred to as the driving point impedance because it is the impedance at the place in the network at which ... This result may seem counterintuitive since admittance is the reciprocal of impedance, but is easily proved. If the impedance ...
Electrical voltage V, current I, resistivity R, impedance Z, wattage P. ... electric pressure or electric tension is the difference in electric potential between two points, which (in a static electric ... Similarly, in an electrical circuit, the work done to move electrons or other charge-carriers is equal to "electrical pressure ... Electric potential differences between points can be caused physically by electric charge build up or imbalance (eg. well known ...
AC impedance spectroscopy Electrical resistivity measurement of concrete Reynolds, John (1997). An Introduction to Applied and ... complex impedance, equivalent to the amount of resistance and phase shift between electric current and voltage. The usual ...
A simple solution is to add electrical impedance to the circuit. This limits the rate at which current can increase, which ... Electric power distribution systems include circuit breakers to disconnect power in case of a fault, but to maximize ... A fault current limiter is a nonlinear element which has a low impedance at normal current levels, but presents a higher ... In normal operation, current flows through the superconductor without resistance and negligible impedance. If a fault develops ...
From 1959 until 1973 Ranck analyzed the flow of electric current in brain, electrical properties of glia, electric impedance of ... Electrical impedance in the subicular area of rats during paradoxical sleep. Ranck JB Jr. Exp Neurol. 1966 Dec;16(4):416-37. ... In the early phase Ranck studied impedance in the brain, providing basic data for any studies or procedures that employ ... Which elements are excited in electrical stimulation of mammalian central nervous system: a review. Ranck JB Jr. Brain Res. ...
Ohm's Law Thévenin's theorem Current source Voltage source Electrical impedance CPP. https://www.cpp.edu/~elab/projects/project ... which is an ideal voltage source in series with the impedance. The impedance Z {\displaystyle Z} retains its value and the new ... If there is a voltage source in series with an impedance, it is possible to find the value of the equivalent current source in ... The converse also holds: if a current source in parallel with an impedance is present, multiplying the value of the current ...
... electrical impedance is also measured in ohms. The siemens (symbol: S) is the SI derived unit of electric conductance and ... It is desirable that one unit of electrical potential will force one unit of electric current through one unit of electrical ... Electrical units so defined were not a coherent system with the units for energy, mass, length, and time, requiring conversion ... Alternatively, the electrical units can be related to the mechanical units by defining, for example, a unit of current that ...
Termination resistors also reduce electrical noise sensitivity due to the lower impedance.[further explanation needed] The ... Electrical signaling is balanced, and multipoint systems are supported. The standard is jointly published by the ... RS-485, also known as TIA-485(-A) or EIA-485, is a standard defining the electrical characteristics of drivers and receivers ... Grounds between buildings may vary by a small voltage, but with very low impedance and hence the possibility of catastrophic ...
A label-free approach to follow the cytotoxic response of adherent animal cells in real-time is based on electric impedance ... This technology is referred to as electric cell-substrate impedance sensing (ECIS). Label-free real-time techniques provide the ...
Kim, K. Y., Kim, B. S., Kim, M. C., Lee, K. J., Ko, Y. J. and Kim, S. (2005). "Electrical impedance imaging of two-phase flows ... Electrical impedance tomography (EIT) is a non-invasive imaging modality in which a cross sectional image of the conductivity ... Boundary estimation in EIT is the term used in the field of electrical impedance tomography, if the inverse problem is the ... Vauhkonen, M. (1997). "Electrical impedance tomography and prior information", PhD Thesis University of Kuopio, Finland online ...
There are visible and infrared spectroscopy, fluorescence spectroscopy, and electric impedance spectroscopy. Each spectroscopy ...
... impedance and capacitance. Electrical conductors such as metals and alloys are contrasted with electrical insulators such as ... A dielectric, or electrical insulator, is a substance that is highly resistant to the flow of electric current. A dielectric, ... Thus, electrical power grids rely on metal cables to distribute electricity. Home electrical systems, for example, are wired ... A capacitor is an electrical device that can store energy in the electric field between a pair of closely spaced conductors ( ...
"Beef meat electrical impedance spectroscopy and anisotropy sensing for non-invasive early assessment of meat ageing". Journal ... An electrical impedance study". New Zealand Journal of Crop and Horticultural Science. 25 (2): 149-157. doi:10.1080/ ... Mabrook, M.F.; Petty, M.C. (2003). "Effect of composition on the electrical conductance of milk". Journal of Food Engineering. ... Rehman, M.; Abu Izneid, J.A.; Abdullha, M.Z.; Arshad, M.R. (2011). "Assessment of quality of fruits using impedance ...
Electrical impedance myography is being studied as a way to measure muscle damage. Muscle MRI is useful for assessment of all ... Electromyogram (EMG) measures the electrical activity in the muscle. EMG can show nonspecific signs of muscle damage or ...
Electrical impedance sensor, which consists of soil probes and using electrical impedance measurement. The most common ... The oscillator signal is propagated along the transmission line into the soil probe, and if the probe's impedance differs from ... However, because of the complex electrical field around the probe, the sensor needs to be calibrated for different soil types. ... Measurement of soil water content using a simplified impedance measuring technique. Journal of Agricultural Engineering ...
DI or DI unit An electronic device that alters the impedance of electric instrument signals (e.g. electric guitar, electric ... With electric guitars, electric basses, Hammond organs, electric piano, and other electric instruments, performers often ... The DI box converts a high-impedance, unbalanced signal from an electric guitar into a low-impedance, balanced signal. Many DI ... clean In reference to the sound of an electric guitar, Fender Rhodes electric piano, or other electric or electronic instrument ...
Electrical Network. Electrical conduction • Electrical resistance • Capacitance • Inductance • Impedance • Resonant cavities • ... Electric charge • Coulomb's law • Electric field • Electric flux • Gauss's law • Electric potential energy • Electric potential ... Ampère's law • Electric current • Magnetic field • Magnetization • Magnetic flux • Biot-Savart law • Magnetic dipole moment • ...
"Amplifier For Electric Currents". United States Patent and Trademark Office.. *^ "Device For Controlling Electric Current". ... Unlike the field-effect transistor (see below), the BJT is a low-input-impedance device. Also, as the base-emitter voltage (VBE ... Institute of Electrical and Electronics Engineers. Retrieved July 4, 2019.. *^ "The Breakthrough Advantage for FPGAs with Tri- ... Also, both devices operate in the depletion-mode, they both have a high input impedance, and they both conduct current under ...
... layer to form an anti-reflection coating can be thought of as analogous to the technique of impedance matching of electrical ...
Wave impedance[edit]. See also: Wave impedance. The wave impedance of a plane electromagnetic wave in a non-conductive medium ... The strong electric field of high intensity light (such as output of a laser) may cause a medium's refractive index to vary as ... Thus refractive index in a non-magnetic media is the ratio of the vacuum wave impedance to the wave impedance of the medium. ... is the vacuum wave impedance, μ and ϵ are the absolute permeability and permittivity of the medium, εr is the material's ...
dB electrical.. dBo. dB optical. A change of 1 dBo in optical power can result in a change of up to 2 dBe in electrical signal ... dB(VRMS) - voltage relative to 1 volt, regardless of impedance.. dBVU. dB volume unit. dBW. dB(W) - power relative to 1 watt.. ... "Electrical Engineering. 73 (6): 550-555. doi:10.1109/EE.1954.6438830.. *^ "Meeting minutes" (PDF). Consultative Committee for ... dB electrical.. dBf. dB(fW) - power relative to 1 femtowatt.. dBFS. dB(full scale) - the amplitude of a signal compared with ...
Derived electrical parameters[edit]. *Characteristic impedance in ohms (Ω). The complex impedance Z of an infinite length of ... The characteristic impedance is given by[9] Z. 0. =. 1. 2. π. μ. ϵ. ln. ⁡. D. d. ≈. 60. Ω. ϵ. r. ln. ⁡. D. d. ≈. 138. Ω. ϵ. r. ... That value is Z0, the characteristic impedance of the cable: Z. 0. =. s. L. s. C. =. L. C. {\displaystyle Z_{0}={\sqrt {\frac { ... Choice of impedance[edit]. The best coaxial cable impedances in high-power, high-voltage, and low-attenuation applications were ...
The most practical dissociation method is probably an electrical discharge.[ambiguous] Argon-hydrogen gas compositions with ... leading to random malfunctions on circuits with high impedances. Different types of fluxes are differently prone to cause these ... Electrical solder with a rosin core, visible as a dark spot in the cut end of the solder wire. ... Deterioration of electrical properties of printed circuit boards, as soldering temperatures are above the glass transition ...
Institute of Electrical and Electronic Engineers. 40 (10): 640. doi:10.1109/81.246140. Retrieved February 6, 2014.. ... One version of Chua's circuit, where the nonlinear Chua's diode is synthesized by an op amp negative impedance converter (OPA1 ... Institute of Electrical and Electronic Engineers. 40 (10): 658. doi:10.1109/81.246141. Retrieved February 6, 2014.. ... The function f(x) describes the electrical response of the nonlinear resistor, and its shape depends on the particular ...
Impedance: A test to measure lead integrity. Large and/or sudden increases in impedance can be indicative of a lead fracture ... "IEEE Milestone in Electrical Engineering and Computing". Retrieved September 5, 2009.. *^ Harvard News Office. "Harvard Gazette ... In 1950, Canadian electrical engineer John Hopps designed and built the first external pacemaker based upon observations by ... Note the circle around one of the sharp electrical spike in the position where one would expect the P wave. ...
Lastly, more efficient battery characteristics tools, for instance, electrochemical impedance spectroscopy (EIS) should be used ... "US NREL: Electric Vehicle Battery Thermal Issues and Thermal Management" (PDF).. *^ "Electric cars wait in the wings". Manawatu ... is a battery used to power the electric motors of a battery electric vehicle (BEV) or hybrid electric vehicle (HEV). These ... "Modec electric truck - DIY Electric Car Forums". www.diyelectriccar.com. Retrieved 26 April 2020.. ...
The load that a driver presents to an amplifier consists of a complex electrical impedance-a combination of resistance and both ... When an electrical signal is applied to the voice coil, a magnetic field is created by the electric current in the voice coil, ... In the examples that follow, assume (for simplicity) that the drivers being compared have the same electrical impedance, are ... Electrical characteristics of dynamic loudspeakers[edit]. Main article: Electrical characteristics of dynamic loudspeakers ...
The fourth unit could be chosen to be electric current, voltage, or electrical resistance.[50] Electric current with named unit ... resistance, impedance, reactance V/A kg⋅m2⋅s−3⋅A−2. ... electric charge or quantity of electricity s⋅A volt V voltage ( ... Giorgi later identified the need for an electrical base unit, for which the unit of electric current was chosen for SI. Another ... electrical conductance is the inverse of electrical resistance, with the consequence that the siemens is the inverse of the ohm ...
Also of help in the action of peristalsis is the basal electrical rhythm that determines the frequency of contractions.[35] The ...
A high-voltage, direct current (HVDC) electric power transmission system (also called a power superhighway or an electrical ... A detailed knowledge of the harmonic impedance of the AC system, at a wide range of frequencies, is needed in order to design ... Electric power distribution. Electricity economics. Power station technology. Portals. Energy. Renewable energy. Sustainable ... Corona discharge is the creation of ions in a fluid (such as air) by the presence of a strong electric field. Electrons are ...
Since a small loop antenna is essentially a coil, its electrical impedance is inductive, with an inductive reactance much ... Since the transverse magnetic and electric fields of a propagating electromagnetic wave are at right angles, the electric field ... In addition to other common impedance matching techniques such as a gamma match, transmitting loops are sometimes impedance ... impedance. A parallel resonance, on the other hand, leads to a very large impedance seen at the feedpoint when the capacitor's ...
Electrical impedance. *Extra-sensory perception. *Human Potential Movement. *Hypnosis. *Large Group Awareness Training ...
Micro hybrid electric vehicles batteries were tested at a 70% SoC in a pulse charge-discharge pattern. UltraBattery had about ... The 'smart building' system, which includes 163 UltraBattery cells (500 Ah, 2 volts), also monitors cell voltage, impedance and ... PNM, the leading electric utility company in New Mexico, United States, has integrated an UltraBattery energy storage system ... UltraBattery can be used for a range of energy storage applications, such as: In hybrid electric vehicles (HEVs) To store ...
The charge remains until it is able to move away by means of an electric current or electrical discharge. Static electricity is ... Transformer oil is part of the electrical insulation system of large power transformers and other electrical apparatus. Re- ... and at least one of the surfaces has a high resistance to electric current (and is therefore an electrical insulator). The ... J. J. Lowke (1992). "Theory of electrical breakdown in air". Journal of Physics D: Applied Physics. 25 (2): 202-210. Bibcode: ...
"University of Maryland; Electrical Engineering Department. Retrieved 2009-07-07.. *^ Ward, David W.; Nelson, Keith A; Webb, ... Since the flow of energy remains the same in both materials (media), the impedance of the NIM matches the RHM. Hence, the sign ... In ordinary optical materials, the curl equation for the electric field show a "right hand rule" for the directions of the ... This first composite metamaterial is then composed of split-ring resonators and electrical conducting posts.[5] ...
Grossi, M.; Lazzarini, R.; Lanzoni, M.; Riccò, B. (2011). "A novel technique to control ice-cream freezing by electrical ... Grossi, M.; Lanzoni, M.; Lazzarini, R.; Riccò, B. (2012). "Automatici ce-cream characterization by impedance measurements for ...
Electrical engineeringWikipedia:WikiProject Electrical engineeringTemplate:WikiProject Electrical engineeringelectrical ... The impedance has a rectangular box, but it is filled with black, not empty like a resistor. -Preceding unsigned comment added ... Why is power(electric) transmitted at high voltage when power loss due to ohmic heating is V2/R as well as I2R? Why does the ... Pretty much every electrical circuit uses resistors for one purpose or another. The simplest application I can think of would ...
Propagation of electric pulses in cables is used to detect and localize defects in electric wiring. Ultrasonic reflectometry: A ... The waves reflected at the interface travel back to the transducer, then the impedance of a sample is determined by measuring ...
the intrinsic wave impedance of a medium (e.g. the impedance of free space) ... the SI unit measure of electrical resistance, the ohm. *angular velocity / radian frequency (rev/min) ...
Distortion is most commonly used with the electric guitar, but may also be used with other electric instruments such as bass ... With no change in flux there is no back E.M.F. and hence no reflected impedance. The transformer and valve combination then ... These effects are used with electric guitars, electric basses (fuzz bass), electronic keyboards, and more rarely as a special ... A. J., Millard (2004). The Electric Guitar: A History of an American Icon. JHU Press. p. 136.. ...
Electrical properties include conductivity, resistance, impedance and capacitance. Electrical conductors such as metals and ... Thus, electrical power grids rely on metal cables to distribute electricity. Home electrical systems, for example, are wired ... A capacitor is an electrical device that can store energy in the electric field between a pair of closely spaced conductors ( ... A dielectric, or electrical insulator, is a substance that is highly resistant to the flow of electric current. A dielectric, ...
... electrical activity refers to sharp bursts of electrical activity followed by low frequency waves. "Trace alternant" electrical ... Therefore, it can be difficult getting a usable signal because of impedance between the skin and the electrode.[60][59] Some ... The electric potential generated by an individual neuron is far too small to be picked up by EEG or MEG.[49] EEG activity ... Nunez PL, Srinivasan R (1981). Electric fields of the brain: The neurophysics of EEG. Oxford University Press. ISBN ...
is the electrical conductivity, ω. {\displaystyle \omega }. is the field frequency, and i. {\displaystyle i}. is the imaginary ... impedance sensing: particles collecting at the electrode edge have an influence on the impedance of the electrodes - this ... Dielectrophoresis occurs when a polarizable particle is suspended in a non-uniform electric field. The electric field polarizes ... Pohl, H. A. (1978). Dielectrophoresis: The Behavior of Neutral in Nonuniform Electric Fields. Cambridge University Press. ISBN ...
A generic vector wave for the electric field. E. =. E. 0. f. (. k. ^. ⋅. x. −. c. 0. t. ). {\displaystyle \mathbf {E} =\mathbf ... Impedance of free space. *Radiation reaction. *Risks and benefits of sun exposure ... In electrical conductors, such induced bulk movement of charges (electric currents) results in absorption of the EMR, or else ... In fact, magnetic fields can be viewed as electric fields in another frame of reference, and electric fields can be viewed as ...
The impedance seen by the panel determines the operating point of the solar panel. Thus by varying the impedance seen by the ... For most purposes, FF, Voc, and Isc are enough information to give a useful approximate model of the electrical behavior of a ... Changing the duty ratio of the DC-DC converter results in an impedance change as seen by the panel. At a particular impedance ( ... Electrical circuits can be designed to present arbitrary loads to the photovoltaic cells and then convert the voltage, current ...
"Recent Patents on Electrical & Electronic Engineering (Formerly Recent Patents on Electrical Engineering). 2 (1): 27-39. doi: ... For low impedance loads near zero ohms, as the generator resistance rises the power delivered to the load decreases. To lower ... Unlike heat engines, the solid state electrical components typically used to perform thermal to electric energy conversion have ... A direct electric current will flow in the circuit when there is a temperature difference between the ends of the materials. ...
a b c d e f g h i Brown B.H. (2003) "Electrical Impedance Tomography (EIT) - A Review". J. Med. Eng. Technol. 27(3): 97-108. ... a b c d e f g h i Holder D.S., Electrical Impedance Tomography: Methods, History and Applications, Institute of Physics, 2004. ... Electrical impedance tomography (EIT) is a noninvasive type of medical imaging in which the electrical conductivity, ... a b c d e f g Bodenstein M., David M., Markstaller K. (2009) "Principles of electrical impedance tomography and its clinical ...
Bio-electrical Impedance Analysis (BIA) is a simple painless procedure which enables a doctor or healthcare provider to analyze ... Bio-electrical Impedance Analysis (BIA) is a simple painless procedure which enables a doctor or healthcare provider to analyze ... Then a small electrical current is passed through the body and measurements are made. The electrical current is so small that ...
... loudspeakers High impedance Immittance Impedance analyzer Impedance bridging Impedance cardiography Impedance control Impedance ... Instruments used to measure the electrical impedance are called impedance analyzers. The term impedance was coined by Oliver ... In electrical engineering, electrical impedance is the measure of the opposition that a circuit presents to a current when a ... to rapidly measure the electrical impedance of various electrical devices. The LCR meter (Inductance (L), Capacitance (C), and ...
Electrical impedance myography, or EIM, is a non-invasive technique for the assessment of muscle health that is based on the ... Interest in electrical impedance dates back to the turn of the 20th century, when physiologist Louis Lapicque postulated an ... Electrical impedance of muscle tissue is anisotropic; current flowing parallel to muscle fibers flows differently from current ... Standard bioelectrical impedance analysis (BIA), like EIM, also employs a weak, high frequency electric current to measure ...
Further adjustment of the electrical conductivity may also be achieved by varying the conductivity of individual fibers ... and electrical shunt means disposed along the conductive material for causing more uniform resistivity between any two equally ... A flexible transcutaneous electrical nerve and/or muscle stimulation electrode is provided which utilizes a conductive material ... spaced apart points on the conductive material than without the electrical shunt means. ...
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... ... Genetic Algorithm Electrical Impedance Tomography Resistivity Distribution Mesh Group Resistivity Profile These keywords were ... In electrical impedance tomography (EIT), various image reconstruction algorithms have been used in order to compute the ...
... with the factorization method to derive a new non-iterative algorithm for the detection of inclusions in electrical impedance ... In this work we study localized electric potentials that have an arbitrarily high energy on some given subset of a domain and ... Localized potentials in electrical impedance tomography. Bastian Gebauer 1, 1. Institut für Mathematik, Johannes Gutenberg- ... Keywords: Electrical impedance tomography, factorization method., Calderon problem. Mathematics Subject Classification: 35J25, ...
A. Abbasi, B. V. Vahdat and G. E. Fakhim, An inverse solution for 2D electrical impedance tomography based on electrical ... A. Abbasi, B. V. Vahdat and G. E. Fakhim, An inverse solution for 2D electrical impedance tomography based on electrical ... Electrical impedance tomography with multiplicative regularization. Ke Zhang 1, , Maokun Li 1,, , Fan Yang 1, , Shenheng Xu 1, ... D. Liu, A. K. Khambampati and J. Du, A parametric level set method for electrical impedance tomography, IEEE Trans. Med. Imag. ...
Cell based impedance sensing is becoming a new biophysical and cellular technology in cell based analyses. The technology has ... Application of Electric Cell-Substrate Impedance Sensing in Evaluation of Traditional Medicine on the Cellular Functions of ... Electrical Cell-Substrate Impedance Sensing for Measuring Cellular Transformation, Migration, Invasion, and Anticancer Compound ... Electric Cell-Substrate Impedance Sensing as a Screening Tool for Wound Healing Agents ...
Few effective technologies exist for sensing in dark or murky underwater situations. For this reason, we have been exploring the use of a novel biologicall
Electrical Impedance Test for Cervical Cancer Developed. April 21st, 2005 Editors Ob/Gyn ... Studies using an electrical impedance probe indicate that early tissue cell abnormalities can be immediately identified, ... In tissue cells, low frequency electrical currents travel around cells and can inform doctors of cell shapes and how they are ...
To test whether electrical skin impedance at each of three acupuncture points (APs) is significantly lower than at nearby sites ... Electric Conductivity. Electric Impedance / classification*. Female. Galvanic Skin Response*. Humans. Male. Meridians / ... OBJECTIVES: To test whether electrical skin impedance at each of three acupuncture points (APs) is significantly lower than at ... Impedance values at APs were not significantly less than at MPs or NPs. Impedance values at MPs were also not significantly ...
Magnetic resonance driven electrical impedance tomography: a simulation study.. Negishi M1, Tong T, Constable RT. ... Magnetic resonance electrical impedance tomography (MREIT) is a method for reconstructing a three-dimensional image of the ... In this paper, we present a new method called magnetic resonance driven electrical impedance tomography (MRDEIT), where the ... a vector wave equation for the electric field is used as the basis of the analysis instead of a quasi-static approximation. ...
Airway Closure Could Be Confirmed by Electrical Impedance Tomography.. Sun XM1, Chen GQ1, Zhou YM1, Yang YL2, Zhou JX1. ... 2 Beijing Electric Power Hospital, Capital Medical University Beijing, China.. Comment on. *Airway Closure in Acute Respiratory ...
... Fei Yang,1 Jie Zhang,2 ... M. J. Moskowitz, T. P. Ryan, K. D. Paulsen, and S. E. Mitchell, "Clinical implementation of electrical impedance tomography ... I. Frerichs, J. Scholz, and N. Weiler, "10: electrical impedance tomography and its perspectives in intensive care medicine," ... electric impedance tomography versus gamma scintigraphy," Clinical Nutrition, vol. 25, no. 4, pp. 671-680, 2006. View at ...
VENTILATION INHOMOGENEITY ANALYSIS USING ELECTRICAL IMPEDANCE TOMOGRAPHY IMAGE PROCESSING. Syedah Sadaf Zehra, Inam Ul Ahad , ... a validation study on electrical impedancetomography, Am J Respir Crit Care Med. 169(7), 2004,791-800 ...
Establishing Muscle Impedance Parameters With Electrical Impedance Myography. The safety and scientific validity of this study ... Device: electrical impedance myography (EIM) EIM is a measure of impedance. EIM is a measure of the obstruction of flow of ... Device: electrical impedance myography (EIM) EIM is a measure of impedance. EIM is a measure of the obstruction of flow of ... Application of Electrical Impedance Myography (EIM) to Establish Muscle Impedance Parameters as a Potential Biomarker of ...
... provides functional images of an electrical conductivity distribution inside the human body. Since the 1980s, many po ...
... Mustapha Azzouz,1 Martin Hanke,2 ... Mustapha Azzouz, Martin Hanke, Chantal Oesterlein, and Karl Schilcher, "The Factorization Method for Electrical Impedance ...
... s electrical impedance and exhibits a far temporal resolution of up to 40 tomograms per second. Because of electrical impedance ... Electric Impedance Tomography Bronchoscopy Change in Lung Impedance Due to Ventilation Recruitment Improvement the Treatment of ... Bronchoscopy and Electric Impedance Tomography (EIT) Pilot Study (Broncho-EIT). The safety and scientific validity of this ... Electrical Impedance Tomography (EIT)is a technique based on the injection of small currents and voltage measurements using ...
... which utilizes coupling between electric and acoustic modalities. Based on the forward solver along different current ... Ultrasound modulated electrical impedance tomography (UMEIT) is a novel hybrid imaging technique, ... An Instrumental Electrode Configuration for 3D Ultrasound Modulated Electrical Impedance Tomography IEEE Sens J. 2017;17(24): ... Ultrasound modulated electrical impedance tomography (UMEIT) is a novel hybrid imaging technique, which utilizes coupling ...
Data collected using scalp electrode in humans matched known tissue impedance spectra and was stable over frequency. The ... A highly versatile Electrical Impedance Tomography (EIT) system, nicknamed the ScouseTom, has been developed. The system allows ... Electrical Impedance Tomography; brain imaging; long term monitoring; evoked activity; open source hardware; Arduino Electrical ... A Versatile and Reproducible Multi-Frequency Electrical Impedance Tomography System. James Avery * , Thomas Dowrick. ...
electric stress exceeds 500 kV/m.. Soil Ionization starts at field strengths above 300 kV/m.. Strength=(400+710 t-0.75) kV/m (8 ... Surge impedance coupling from driven (OHGW) to. In the time after the adjacent-tower reflection, from 3 to. undriven (phase) ... Surge impedance coupling, modified by. 6. CALCULATION OF CRITICAL CURRENT. using the geometric mean of the corona and geometric ... electrical strength of insulator combinations such as wood [7] W. Janischewskyj, W.A.Chisholm and J. Beattie,LightningGround. ...
In electrical impedance tomography the electrical conductivity inside a physical body is computed from electro-static boundary ... In electrical impedance tomography the electrical conductivity inside a physical body is computed from electro-static boundary ... 3D reconstruction for partial data electrical impedance tomography using a sparsity prior. Henrik Garde 1, and Kim Knudsen 2, ... H. Garde and K. Knudsen, Sparsity prior for electrical impedance tomography with partial data,, Inverse Probl. Sci. Eng., (2015 ...
Development of electrical impedance tomography of microwave ablation Author(s): A. McEwan; H. Wi; D. T. Nguyen; P. Jones; V. ... 208 tetrapolar electrical impedance measurements were obtained at 30 frame/s from a 16 electrode EIT system. In the porcine ... In this study we assess the feasibility of electrical impedance tomography (EIT) to track the temperature changes during ... model ventilation artefact was removed by low pass filtering and successful ablation related impedance change image sequences ...
... electrical engineering) abbreviated? MB-IIN stands for Multi-Band Impedance Inverter Network (electrical engineering). MB-IIN ... is defined as Multi-Band Impedance Inverter Network (electrical engineering) rarely. ... a href=https://www.acronymfinder.com/Multi_Band-Impedance-Inverter-Network-(electrical-engineering)-(MB_IIN).html,MB-IIN,/a, ... S.v. "MB-IIN." Retrieved October 22 2020 from https://www.acronymfinder.com/Multi_Band-Impedance-Inverter-Network-(electrical- ...
For the two dimensional inverse electrical impedance problem in the case of piecewise constant conductivities with the currents ... Electrical impedance tomography using a point electrode inverse scheme for complete electrode data. Fabrice Delbary 1, and ... Keywords: boundary integral equations, Newton scheme., Electrical impedance tomography, point electrode model, complete ... F. Delbary and R. Kress, Electrical impedance tomography with point electrodes,, J. Integral Equations Appl., 22 (2010), 193. ...
... DTU Health Tech Share on ... Postdoc in MR Electric Impedance Tomography for Dose Control of Transcranial Electric Stimulation ... We are seeking a highly motivated Postdoc candidate to work on novel reconstruction methods for MR Electric Impedance ... overarching aim in this project is to leverage our recently developed MREIT methods and FEM models of the TDCS-induced electric ...
Electrical Impedance Tomography of Neonatal Brain Activity A T Tidswell ; A T Tidswell ... A T Tidswell, JS Wyatt, RH Bayford, DS Holder; Electrical Impedance Tomography of Neonatal Brain Activity. Clin Sci (Lond) 1 ... Detection of Changes in Intrathoracic Fluid in Man Using Electrical Impedance Tomography Clin Sci (Lond) (July,1994) ...
Key Words: Electrical impedance tomography, prostate cancer, surgical margin assessment, radical prostatectomy ... Towards Microendoscopic Electrical Impedance Tomography for Intraoperative Surgical Margin Assessment Featured Articles ... we have developed a novel Microendoscopic Electrical Impedance Tomography (EIT) probe that can be introduced into the surgical ... Significantly different electrical property signatures have been observed between benign and malignant prostate tissues, and we ...
  • [4] However, in contrast to linear x-rays used in Computed Tomography, electric currents travel three dimensionally along the path of least resistivity. (wikipedia.org)
  • Quantification of ventilation distribution in regional lung injury by electrical impedance tomography and xenon computed tomography. (semanticscholar.org)
  • 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)
  • Studying the electrical impedance variations in banana ripening using electrical impedance spectroscopy. (academicjournals.org)
  • Determination of mango ripening degree by electrical impedance spectroscopy. (academicjournals.org)
  • Electrical impedance spectroscopy (EIS) for biological analysis and food characterization: a review. (academicjournals.org)
  • Assessment of Ripening Degree of Avocado by Electrical Impedance Spectroscopy and Support Vector Machine. (academicjournals.org)
  • Electrical impedance spectroscopy (EIS) is a noninvasive method that aims to help diagnose skin cancer. (uzh.ch)
  • Electrical impedance spectroscopy (EIS) may therefore be able to aid clinicians in differentiating between benign and malignant skin lesions. (diva-portal.org)
  • Electric impedance spectroscopy (EIS) can provide cellular information of biological tissue. (fraunhofer.de)
  • Since ECIS and its associated model to transform the impedance spectroscopy data in biologically relevant parameters was introduced in its current form to the scientific community by Giaever and Keese in 1991 2 , it has often been referred to as a system for the measurement of TEER (trans-epithelial electrical resistance), which is not accurate. (jove.com)
  • BACKGROUND: Acquisition of electrical impedance spectroscopy (EIS) measurements enables one to obtain information about the features of cell cultures, which can be applied for real-time and on-linemonitoring purposes. (upc.edu)
  • Electrical impedance spectroscopy is a widely recognised, non-destructive method for examining the properties of different materials and objects. (eliko.ee)
  • The above notwithstanding, impedance spectroscopy of doped cells in the frequency range customarily employed by liquid crystal devices, 100 Hz?10 kHz, shows a relatively simple resistor/capacitor response where the components of the cell can be univocally assigned to single components of the electrical equivalent circuit. (upm.es)
  • The low-frequency complex electrical conductivity in the mHz to kHz range has been shown to enable an improved textural, hydraulic, and biogeochemical characterization of the subsurface using electrical impedance spectroscopy (EIS) methods. (uni-bonn.de)
  • Electrical impedance spectroscopy of a cell suspension can be used to extract an average measure of the electrical properties of single cells. (asme.org)
  • Impedance spectroscopy has been used to investigate the conductivity displayed by diamond doped with boron in an intrinsic-delta-layer-intrinsic multilayer system with differing delta-layer thicknesses. (ucl.ac.uk)
  • Airway Closure Could Be Confirmed by Electrical Impedance Tomography. (nih.gov)
  • 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)
  • Electrical conductivity varies considerably among various biological tissues (absolute EIT) or the movement of fluids and gases within tissues (difference EIT). (wikipedia.org)
  • Further adjustment of the electrical conductivity may also be achieved by varying the conductivity of individual fibers utilized in the conductive fabric. (google.com)
  • Magnetic resonance electrical impedance tomography (MREIT) is a method for reconstructing a three-dimensional image of the conductivity distribution in a target volume using magnetic resonance (MR). In MREIT, currents are applied to the volume through surface electrodes and their effects on the MR induced magnetic fields are analyzed to produce the conductance image. (nih.gov)
  • In electrical impedance tomography the electrical conductivity inside a physical body is computed from electro-static boundary measurements. (aimsciences.org)
  • 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)
  • Electrical Impedance Tomography (BIT) is the problem to estimate the conductivity distribution of an object, by injecting currents through its surface and measuring the resulting voltage distribution on the surface. (witpress.com)
  • The impedance and electrical conductivity behavior of gellan gum hydrogels containing the conducting fillers poly(3,4- ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) and vapour grown carbon nanofibers (VGCNF) is presented. (spie.org)
  • Electrical impedance tomography (EIT) is a technique for reconstructing the conductivity distribution inside an inhomogeneous distribution by injecting currents at the boundary of a subject and measuring the resulting changes in voltage. (harvard.edu)
  • Laboratory measurements of the complex electrical conductivity in a broad frequency range (i.e. mHz to kHz) using spectral induced polarization (SIP) measurements have shown great promise to characterize important hydrological properties (e.g. hydraulic conductivity) and biogeochemical processes. (uni-bonn.de)
  • However, translating these findings to field applications remains challenging, and significant improvements in spectral electrical impedance tomography (EIT) are still required to obtain images of the complex electrical conductivity with sufficient accuracy in the field. (uni-bonn.de)
  • The aim of this study is to present recent improvements in the inversion and processing of broadband field EIT measurements, and to evaluate the accuracy and spectral consistency of the obtained images of the real and imaginary part of the electrical conductivity. (uni-bonn.de)
  • In a first case study, time-lapse surface EIT measurements were performed during an infiltration experiment to investigate the spectral complex electrical conductivity as a function of water content. (uni-bonn.de)
  • State-of-the-art data processing and inversion approaches were used to obtain images of the complex electrical conductivity in a frequency range of 100 mHz to 1 kHz, and integral parameters were obtained using Debye decomposition. (uni-bonn.de)
  • Results showed consistent spectral and spatial variation of the phase of the complex electrical conductivity in a broad frequency range, and a complex dependence on water saturation that was reasonably consistent with laboratory EIT measurements. (uni-bonn.de)
  • Integral representations for the solution of two-layer inhomogeneous conductivity problem are derived and asymptotic expansions of a perturbed electrical field are obtained. (global-sci.org)
  • In Electrical Impedance Tomography (EIT) one wants to image the conductivity distribution of a body from current and voltage measurements carried out on its boundary. (arxiv.org)
  • Electrical Impedance Tomography (EIT) problem consists of finding the electric conductivity inside a conductive body from simultaneous measurements of electric potential and current at its boundary. (rice.edu)
  • In order to investigate the contribution of arterial radius and center-line velocity to the blood conductivity and electrical impedance of pulsatile flow in the human common carotid artery, we proposed three simplified mathematical models to describe the relationship between the center-line velocity, the arterial radius, and the blood conductivity. (springer.com)
  • Moreover, the change in arterial radius contributed much more to the electrical impedance than the change in blood conductivity induced by the center-line velocity. (springer.com)
  • These nanoparticles are known to reorient with liquid crystals in electric fields, causing significant variations of conductivity at minute concentrations of tens or hundreds ppm. (upm.es)
  • However, the required accuracy of 1 mrad in the phase measurements is difficult to achieve for a broad frequency bandwidth because of electromagnetic (EM) coupling effects at high frequencies and the lack of inversion schemes that consider the spectral nature of the complex electrical conductivity. (uni-bonn.de)
  • The objective of electrical impedance tomography is to reconstruct the internal conductivity of a physical body based on measurements of current and potential at a finite number of electrodes attached to its boundary. (dtu.dk)
  • Although the conductivity is the quantity of main interest in impedance tomography, a real-world measurement configuration includes other unknown parameters as well: The information on the contact resistances, electrode positions, and body shape is almost always incomplete. (dtu.dk)
  • abstract = "The monotonicity-based approach has become one of the fundamental methods for reconstructing inclusions in the inverse problem of electrical impedance tomography. (aau.dk)
  • Glidewell, M., Ng, K.T.: Anatomically Constrained Electrical Impedance Tomography for Anisotropic Bodies Via a Two-step Approach. (springer.com)
  • 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)
  • The primary aim of this study is to assess the changes in the impedance parameters of muscles in inclusion body myositis (IBM) through electrical impedance myography (EIM), an emerging non-invasive electrodiagnostic technology. (clinicaltrials.gov)
  • In this pilot study, the electrical impedance myography (EIM) parameters of individuals with inclusion body myositis (IBM) will be compared with age and sex matched normal data. (clinicaltrials.gov)
  • Electrical impedance myography (EIM) is a technique for the evaluation of neuromuscular diseases, including amyotrophic lateral sclerosis and muscular dystrophy. (mit.edu)
  • Electrical impedance myography (EIM) is a non-invasive, painless, objective technique to quantify muscle pathology. (nih.gov)
  • The purpose of this study is to assess Electrical Impedance Myography (EIM) as an outcome measure in patients with Idiiopathic Inflammatory Myopathies (IIM) or Myositis. (mayo.edu)
  • Electrical impedance myography in spinal muscular atrophy: a longitudinal study. (harvard.edu)
  • 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)
  • 1 Tianjin Key Laboratory of Process Measurement and Control, School of Electrical and Information Engineering, Tianjin University, Tianjin 300072, China. (nih.gov)
  • As a patient is already equipped with cardiac leads connected to a stimulation device which can also record the cardiac electrical activity, the main idea of this work is to investigate the use of an electrical measurement that could characterize the fibrotic lead encapsulation, with the final objective to embed this characterization method in the implanted circuit. (archives-ouvertes.fr)
  • In addition, an axis studying the feasibility of embedded impedance measurement for in vivo mimicking conditions is also discussed. (archives-ouvertes.fr)
  • The use of a four-electrodes measurement system decreased the dependency on the electrode interface's impedance, and thus resulted in a systemmore sensitive to the cell features. (upc.edu)
  • Ebrahim M, Hegde S, Printz B, Abcede M, Proudfoot JA, Davis C (2016) Evaluation of impedance cardiography for measurement of stroke volume in congenital heart disease. (springer.com)
  • The compact impedance-mapping technology can be used for creating portable connected devices or large-scale measurement systems. (eliko.ee)
  • This study evaluates the measurement of CO in normal pregnant women by non-invasive, thoracic electrical bio-impedance. (journals.co.za)
  • The limitations of CO measurement by thoracic electrical bio-impedance and thermodilution method are discussed, and refinements in methods are suggested to achieve acceptable repeatability of these measurements. (journals.co.za)
  • This study presents an electrical impedance measurement of sickle cell suspension with normal red blood cells as control. (asme.org)
  • Studies have shown that the developed virtual bench is suitable for preliminary testing of all analog components of the channel.The use of the developed virtual bench will allow optimizing the time and material costs for conducting experimental research in the process of developing hardware for technical means of electrical impedance tomography. (eduzhai.net)
  • We also show how to construct such potentials numerically and use a connection with the factorization method to derive a new non-iterative algorithm for the detection of inclusions in electrical impedance tomography. (aimsciences.org)
  • B. Gebauer and N. Hyvönen, Factorization method and irregular inclusions in electrical impedance tomography ,, Inverse Problems , 23 (2007), 2159. (aimsciences.org)
  • Explicit characterization of inclusions in electrical impedance tomography ," SIAM Journal on Mathematical Analysis, Vol. (thefreedictionary.com)
  • TY - JOUR T1 - Reconstruction of Small Inclusions in Electrical Impedance Tomography Problems JO - East Asian Journal on Applied Mathematics VL - 2 SP - 280 EP - 294 PY - 2019 DA - 2019/03 SN - 9 DO - http://doi.org/10.4208/eajam.030518.210918 UR - https://global-sci.org/intro/article_detail/eajam/13083.html KW - Electrical impedance tomography, small inclusion, inverse problem, uniqueness. (global-sci.org)
  • The present study concerns with determination of an optimal spot-electrodes array for voltage pick-up through the detailed measurements of pulsatile components of the thoracic impedance along the medial line of the thorax using an 11x2 channels impedance mapping system. (biomedsearch.com)
  • Electrical impedance tomography (EIT) is a non-invasive imaging technique that can measure cardiac-related intra-thoracic impedance changes. (csem.ch)
  • Experimental and numerical study on optimal spot-electrodes arrays in transthoracic electrical impedance cardiography. (biomedsearch.com)
  • Transthoracic electrical impedance (or admittance) cardiography is a simple technique for the non-invasive and continuous monitoring of stroke volume or cardiac output by detecting the electrical impedance of a thorax which is roughly assumed to be a two-compartment coaxial cylindrical model composed of the aorta and its surrounding thoracic tissues. (biomedsearch.com)
  • Tomsin K, Mesens T, Molenberghs G, Gyselaers W (2011) Diurnal and position-induced variability of impedance cardiography measurements in healthy subjects. (springer.com)
  • The ex vivo part presents the characterization of tissue of different natures, healthy or collagenous, it was developed with the IHU LIRYC laboratory, on porcine or ovine cardiac tissue (ventricles mainly), with stimulation electrodes used on patients The impedance spectra are analyzed using a known electrical model from which characteristic parameters of the two tissue types are extracted. (archives-ouvertes.fr)
  • The in vitro part presents the electrical characterization, using impedance measurements, in parallel to the biological characterization, using immunocytochemistry, of a cellular fibrosis model. (archives-ouvertes.fr)
  • After a statistical analysis, the impedance values show a significantly different signature for cultures with growth factor, with respect to sham cultures, while the biological characterization confirmed the presence of more activated and differentiated cells over time. (archives-ouvertes.fr)
  • The reciprocal of impedance is admittance, whose SI unit is the siemens, formerly called mho. (wikipedia.org)
  • Objective tests of middle ear function based on the difficulty (impedance) or ease (admittance) of sound flow through the middle ear. (bioportfolio.com)
  • 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)
  • 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)
  • 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)
  • 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)
  • Data collected using scalp electrode in humans matched known tissue impedance spectra and was stable over frequency. (mdpi.com)
  • Past studies have suggested that acupuncture meridians are physiologically characterized by low electrical impedance and anatomically associated with connective tissue planes. (harvard.edu)
  • 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)
  • This phenomenon jeopardizes the device biocompatibility, because it encapsulates the stimulation lead with an "insulating" tissue, creating adherences along the lead and often leading to an increase of the stimulation threshold over time and a larger electrical consumption. (archives-ouvertes.fr)
  • Electrical medical leads having active fixation electrodes, particularly helix electrodes intended to be screwed into body tissue, e.g., the heart, are disclosed having selectively applied insulation to optimize exposed electrode surface area and dispose the exposed electrode surface area toward tissue that is less traumatized by injury caused by screwing in the fixation helix. (google.com)
  • Implantable medical electrical stimulation and/or sensing leads (electrical medical leads) are well known in the fields of tissue stimulation and monitoring, including cardiac pacing and cardioversion/defibrillation, and in other fields of electrical stimulation or monitoring of electrical signals or other physiologic parameters. (google.com)
  • Electrical impedance measurements were performed on 13 atherosclerotic human aortic segments at 67 measuring spots in order to determine whether or not on the basis of these data a distinction can be made between atherosclerotic lesions and normal tissue. (eur.nl)
  • We hypothesized that segments of acupuncture meridians that are associated with loose connective tissue planes (between muscles or between muscle and bone) visible by ultrasound have greater electrical conductance (less electrical impedance) than non-meridian, parallel control segments. (biomedcentral.com)
  • Tissue impedance between the two inner needles was calculated based on Ohm's law (ratio of voltage to current intensity). (biomedcentral.com)
  • At the Pericardium location, mean tissue impedance was significantly lower at meridian segments (70.4 ± 5.7 Ω) compared with control segments (75.0 ± 5.9 Ω) ( p = 0.0003). (biomedcentral.com)
  • Tissue impedance was on average lower along the Pericardium meridian, but not along the Spleen meridian, compared with their respective controls. (biomedcentral.com)
  • Ultrasound imaging of meridian and control segments suggested that contact of the needle with connective tissue may explain the decrease in electrical impedance noted at the Pericardium meridian. (biomedcentral.com)
  • Further studies are needed to determine whether tissue impedance is lower in (1) connective tissue in general compared with muscle and (2) meridian-associated vs. non meridian-associated connective tissue. (biomedcentral.com)
  • 10. Why is the measured impedance of the bladder tissue different from the computational modelling results? (ellibs.com)
  • Written by experts in the area of cell impedance sensing, including the Nobel Laureate Dr Ivar Giaever, this books covers the background of electric cell-substrate impedance sensing, their applications in cell based investigations, particularly in the area of cancer biology. (springer.com)
  • This protocol reviews Electric Cell-substrate Impedance Sensing, a method to record and analyze the impedance spectrum of adherent cells for the quantification of cell attachment, proliferation, motility, and cellular responses to pharmacological and toxic stimuli. (jove.com)
  • Electric Cell-substrate Impedance Sensing (ECIS) is an in vitro impedance measuring system to quantify the behavior of cells within adherent cell layers. (jove.com)
  • ΩΩΩHere we present Electric Cell-substrate Impedance Sensing, known as ECIS, a specific method to measure and analyze the impedance spectrum of adherent cells in culture 1 . (jove.com)
  • Instruments used to measure the electrical impedance are called impedance analyzers. (wikipedia.org)
  • We used a four-electrode method to measure the electrical impedance along segments of the Pericardium and Spleen meridians and corresponding parallel control segments in 23 human subjects. (biomedcentral.com)
  • Cell based impedance sensing is becoming a new biophysical and cellular technology in cell based analyses. (springer.com)
  • We used a commercial impedance sensing device (ECIS®) to assess the migration of the cells following irradiation. (aps.org)
  • The relaxation spectra obtained were fitted to a Cole impedance model and the corresponding parameters analyzed. (upc.edu)
  • Electrical impedance spectra of cell suspensions are obtained in the range of 1000 Hz to 1MHz. (asme.org)
  • The method is illustrated with one typical nonlinear inverse problem, electrical impedance tomography with complete electrode model, under sparsity constraints. (osti.gov)
  • Impedance changes in lung ventilation are investigated in mechanically ventilated patients who routinely undergo bronchoscopy in intensive care medicine. (clinicaltrials.gov)
  • 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)
  • The provision of guidance in ventilator therapy by continuous monitoring of regional lung ventilation, aeration and respiratory system mechanics is the main clinical benefit of electrical impedance to. (bioportfolio.com)
  • Electrical impedance tomography (EIT) is a noninvasive tool that allows real-time imaging of regional ventilation. (ovid.com)
  • Electrical impedance tomography (EIT) is a noninvasive, radiation-free monitoring tool that provides real-time imaging of ventilation at the bedside. (scielo.br)
  • Mechanical ventilation guided by electrical impedance tomography in experimental acute lung injury. (semanticscholar.org)
  • We present a case in which monitoring of trans-pulmonary pressure and ventilation distribution using Electrical Impedance Tomography (EIT) provided essential information for preventing VILI. (eur.nl)
  • In 15 patients with early, mild, diffuse acute respiratory distress syndrome, application of an open lung approach ( vs. a standard management protocol that does not target an "open" lung) resulted in lower driving pressure, improved oxygenation, and more homogeneous distribution of ventilation (assessed by electric impedance tomography). (asahq.org)
  • 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)
  • In our previous reports, we have confirmed that a thorax is nearly assumed as an electrical cylinder model when a pair of current injection spot-electrodes are placed far from the thorax like a placement of the forehead - left medial knee or the mastoid process - lower right abdomen, and that the changes in current distributions associated with cardiac blood ejection are roughly homogeneous around the medial line of the thorax. (biomedsearch.com)
  • This brings us to the main question of our project: does the fibrosis developing around the cardiac leads have an electrical signature?My thesis work is organized along three axes. (archives-ouvertes.fr)
  • Kubicek WG, Karnegis JN, Patterson RP, Witsoe DA, Mattson RH (1966) Development and evaluation of an impedance cardiac output system. (springer.com)
  • Respiratory mechanics, gas exchange, electrical impedance tomography (EIT), cardiac index, and stroke volume variation were measured at baseline and 20 min after OLA implementation (post-OLA). (asahq.org)
  • EIT-based cardiac output estimation relies on the assumption that the amplitude of the impedance change in the ventricular region is representative of stroke volume (SV). (csem.ch)
  • A. Abbasi , B. V. Vahdat and G. E. Fakhim , An inverse solution for 2D electrical impedance tomography based on electrical properties of material blocks, Journal of Applied Sciences , 9 (2009), 1962-1967. (aimsciences.org)
  • 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)
  • We are seeking a highly motivated Postdoc candidate to work on novel reconstruction methods for MR Electric Impedance Tomography (MREIT). (dtu.dk)
  • The multiplicative regularization scheme is applied to three-dimensional electrical impedance tomography (EIT) image reconstruction problem to alleviate its ill-posedness. (bioportfolio.com)
  • A type of impedance plethysmography in which bioelectrical impedance is measured between electrodes positioned around the neck and around the lower thorax. (bioportfolio.com)
  • The aim of this protocol is to offer a generally applicable guide for the usage of this particular type of impedance based cellular assays and provide protocols for some of the key functions from the constantly growing number of applications. (jove.com)
  • Electrical skin impedance at acupuncture points. (biomedsearch.com)
  • OBJECTIVES: To test whether electrical skin impedance at each of three acupuncture points (APs) is significantly lower than at nearby sites on the meridian (MP) and off the meridian (NP). (biomedsearch.com)
  • CONCLUSIONS: Within the reliability limits of our study methods, none of the three APs tested has lower skin impedance than at either of the nearby control points. (biomedsearch.com)
  • These results are not consistent with previous studies that detected lower skin impedance at APs than nearby sites. (biomedsearch.com)
  • Further study is necessary to determine whether MPs have lower skin impedance than nearby NPs. (biomedsearch.com)
  • To apply electrical impedance tomography (EIT) and the new evaluation approach (the functional EIT) in monitoring the development of artificial lung injury. (semanticscholar.org)
  • This is a combined conference for the XIV th International Conference on Electrical Bioimpedance and the 11th Conference on Biomedical Applications of EIT. (eit.org.uk)
  • When developing and determining the principles of construction and algorithms for the operation of electrical impedance tomography devices, it is necessary to verify the adequacy of the adopted circuitry solutions, their technical level and the possibility of practical implementation. (eduzhai.net)
  • M. Brühl and M. Hanke, Numerical implementation of two noniterative methods for locating inclusions by impedance tomography ,, Inverse Problems , 16 (2000), 1029. (aimsciences.org)
  • The goal of this feasibility study is to evaluate the ability of Electrical Impedance Tomography (EIT) for providing regional and quantitative information about the extent and nature of br. (bioportfolio.com)
  • Gaw RL, Cornish BH, Thomas BJ (2007) Comparison of a theoretical impedance model with experimental measurements of pulsatile blood flow. (springer.com)
  • OBJECTIVE A new noninvasive method, electrical impedance tomography (EIT), was used to make pressure-impedance (PI) curves in a lung lavage model of acute lung injury in pigs. (semanticscholar.org)
  • In this report, we propose the application of the Cramer Rao Lower Bound (CRLB) as a performance measure for optimal design of experimental setups in electrical impedance tomography. (actapress.com)
  • We tested the feasibility of intravascular EIS by using a new impedance catheter system with integrated microelectrodes in an experimental animal model. (fraunhofer.de)
  • Considering that the devices for electrical impedance tomography being developed are hardware and software solutions, and their components are complete electronic units that interact with each other, it seems possible to develop an experimental bench.The development of a virtual automated experimental bench for preliminary tests of the main components of the electrical impedance tomography channel is proposed. (eduzhai.net)
  • These expressions are applied to experimental configurations in which the external excitation is either predominately magnetic or electric, and the internal loading is configured to exclude either the electrically or magnetically induced internal currents. (dtic.mil)
  • The experimental results are compared with theoretical calculations appearing in the literature, and the relative importance of the electric and magnetic coupling effects is discussed. (dtic.mil)
  • Muscle impedance parameters can potentially serve as an objective biomarker reflecting disease progression and severity. (clinicaltrials.gov)
  • The correspondence of the main elements of hardware and virtual benches in terms of their functional purpose is shown.For each of the software components of the virtual bench, input actions and output parameters are determined.A schematic diagram of the analog part of the electrical impedance tomography channel has been developed to test the performance of the virtual bench. (eduzhai.net)
  • Electric and magnetic coupling parameters are measured for a braided- shield cable. (dtic.mil)
  • Gaw RL, Cornish BH, Thomas BJ (2008) The electrical impedance of pulsatile blood flowing through rigid tubes: a theoretical investigation. (springer.com)
  • Raaijmakers E, Marcus JT, Goovaerts HG, De Vries PMJM, Faes TJC, Heethaar RM (1996) The influence of pulsatile flow on blood resistivity in impedance cardiograp. (springer.com)
  • 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)
  • Ultrasound modulated electrical impedance tomography (UMEIT) is a novel hybrid imaging technique, which utilizes coupling between electric and acoustic modalities. (nih.gov)
  • Ultrasound modulated electrical impedance tomography. (nih.gov)
  • Combined ultrasound and electrical impedance tomography (EIT) puts 3-D ultrasound imaging together with EIT data in a co-registered volume. (dartmouth.edu)
  • Combining ultrasound and EIT has the potential to greatly improve the quality and spatial resolution of the reconstructed electrical properties. (dartmouth.edu)
  • 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)
  • Conclusion/Significance: Collagenous bands, represented by increased ultrasound echogenicity, are significantly associated with lower electrical impedance and may account for reduced impedances previously reported at acupuncture meridians. (harvard.edu)
  • Impedance is defined as the frequency domain ratio of the voltage to the current. (wikipedia.org)
  • In this paper, we present a new method called magnetic resonance driven electrical impedance tomography (MRDEIT), where the magnetic resonance in each voxel is used as the applied magnetic field source, and the resultant electromagnetic field is measured through surface electrodes or radio-frequency (RF) detectors placed near the surface. (nih.gov)
  • Because the applied magnetic field is at the RF frequency and eddy currents are the integral components in the method, a vector wave equation for the electric field is used as the basis of the analysis instead of a quasi-static approximation. (nih.gov)
  • Avery J, Dowrick T, Faulkner M, Goren N, Holder D. A Versatile and Reproducible Multi-Frequency Electrical Impedance Tomography System. (mdpi.com)
  • Bi-frequency symmetry difference electrical impedance tomography - a novel technique for perturbation detection in static scenes. (bioportfolio.com)
  • The impedance was recorded at a frequency ranging from 1 Hz to 1 MHz. (fraunhofer.de)
  • Alternating current impedance measurements have been made over a wide frequency range on the giant axon from the stellar nerve of the squid, Loligo pealii , during the passage of a nerve impulse. (rupress.org)
  • An instrumental electrode model (IEM) capable of describing the performance of electrical impedance tomography (EIT) systems in the MHz frequency range has been proposed. (strath.ac.uk)
  • Here, we overcome these deficiencies by (i) extending the standard spatial-smoothness constraint in EIT to the frequency dimension, thus enforcing smooth spectral signatures, and (ii) implementing an advanced EM coupling removal procedure using a newly formulated forward electrical model and calibration measurements. (uni-bonn.de)
  • The overarching aim in this project is to leverage our recently developed MREIT methods and FEM models of the TDCS-induced electric fields (www.simnibs.org) to quantify the physical stimulation strength of TDCS in the brain at the individual level. (dtu.dk)
  • Regional pressure volume curves by electrical impedance tomography in a model of acute lung injury. (semanticscholar.org)
  • M. Azzouz, M. Hanke, C. Oesterlein and K. Schilcher, The factorization method for electrical impedance tomography data from a new planar device ,, International Journal of Biomedical Imaging , (2007). (aimsciences.org)
  • DESIGN: Two instruments - Prognos (MedPrevent GmbH, Waldershof, Germany), a constant-current (DC) device, and PT Probe (designed for this study), a 100-Hz sinusoidal-current (AC) device-were used to record electrical impedance at three APs (right Gallbladder 14, right Pericardium 8, and left Triple Energizer 1), and two control sites for each AP. (biomedsearch.com)
  • 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)
  • The EIS device consists of a handheld probe with a disposable electrode that is applied directly on the skin and uses electrical impendence differences to differentiate between normal and abnormal skin lesions. (uzh.ch)
  • A device is described for measuring electrical characteristics of biological tissues with plurality of electrodes and a processor controlling the stimulation. (patents.com)
  • Cross-sectional body imaging that reconstructs pictures of internal organs based on measurements of their electrical activity as detected by electrodes placed on the surface of the body. (thefreedictionary.com)
  • A flexible transcutaneous electrical nerve and/or muscle stimulation electrode is provided which utilizes a conductive material, preferably a conductive fabric, and electrical shunt means disposed along the conductive material for causing more uniform resistivity between any two equally spaced apart. (google.com)
  • 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 [3] the authors proposed a nonlinear integral equation approach that extends a method that has been suggested by Kress and Rundell [10] for the case of perfectly conducting inclusions. (aimsciences.org)
  • A novel method for the imaging of static scenes using Electrical Impedance Tomography (EIT) is reported with implementation and validation using numerical and phantom models. (bioportfolio.com)
  • Electrical impedance scanning (EIS) is a new adjunctive diagnostic method for women breast cancer examination. (eurekamag.com)
  • This paper discusses the electric circuit simulation method in the inverse and direct problems in electrical impedance tomography. (bath.ac.uk)
  • A method includes storing baseline data representing at least one local or global electrical characteristics for at least a portion of a region of interest. (patents.com)
  • K. Eppler and H. Harbrecht, A regularized Newton method in electrical impedance tomography using shape Hessian information. (esaim-cocv.org)
  • Among them is electrical impedance tomography (EIT), a low-cost and label-free imaging method based on electrical stimulations. (escholarship.org)
  • 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)
  • Bernstein DP, Henry IC, Banet MJ, Dittrich T (2012) Stroke volume obtained by electrical interrogation of the brachial artery: transbrachial electrical bioimpedance velocimetry. (springer.com)
  • 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)
  • Muscle composition and microscopic structure change with disease, and EIM measures alterations in impedance that occur as a result of disease pathology. (wikipedia.org)
  • These include static impedance and dynamic impedance (i.e., tympanometry and impedance tests in conjunction with intra-aural muscle reflex elicitation). (bioportfolio.com)
  • To correlate the data obtained by Electrical impedance tomography (EIT) during the spontaneous breathing trials (SBT) on a T-piece, in children, with failure in the trial and Extubation failure. (clinicaltrials.gov)
  • EIT relies on the mathematical processing of impedance data collected non-invasively from patients to reconstruct the 3-D distribution of the electrical properties of the tissues inside the patient. (dartmouth.edu)
  • The impedance inside and outside the stent was analysed and compared with the histomorphometric data. (fraunhofer.de)
  • For an enhanced user experience of this Electric Impedance Tomography Market report, all the facts and figures of statistical and numerical data are represented very well throughout the report. (pharmiweb.com)
  • The impedance data is used for mapping and correlation with a phenomenon of interest. (eliko.ee)
  • Both methodological advances are independently validated, and the improved imaging capability of the overall methodology with respect to spectral electrical properties is demonstrated using borehole EIT measurements in a heterogeneous aquifer. (uni-bonn.de)
  • Impedance values at APs were not significantly less than at MPs or NPs. (biomedsearch.com)
  • Significantly different electrical property signatures have been observed between benign and malignant prostate tissues, and we hypothesize that gauging these properties intraoperatively has the potential to provide clinically relevant information regarding surgical margin pathology. (embs.org)
  • We found significantly reduced electrical impedance at the Large Intestine meridian compared to adjacent control for both frequencies. (harvard.edu)
  • Greater subcutaneous echogenic densities were significantly associated with reduced impedances in both within-site (meridian vs. adjacent control) and between-site (arm vs. thigh vs. lower leg) analyses. (harvard.edu)
  • At the Spleen location, mean impedance for meridian (67.8 ± 6.8 Ω) and control segments (68.5 ± 7.5 Ω) were not significantly different ( p = 0.70 ). (biomedcentral.com)
  • However, other factors such as heart motion can significantly affect this ventricular impedance change. (csem.ch)
  • Measuring cellular impedance in this manner allows the automated study of cell attachment, growth, morphology, function, and motility. (jove.com)
  • We start by studying electrical properties of cells and build a scalable model of cellular electrical response. (escholarship.org)
  • Apfel H (1990) Electrical impedance of the carotid artery in response to various types of stress. (springer.com)