Abstract:
:Temporal changes in the impedance spectra of bioelectrodes in contact with skin provide useful data for comparisons between differing electrode materials and skin preparation methods. Traditional impedance measuring systems employ swept frequency methods which will distort results in the impedance spectra of a sample which has nonstationary electrical characteristics. The system reported here obtains impedance spectra by applying a digitally constructed waveform consisting of many frequency components. This allows impedance values to be measured at a number of frequencies simultaneously. Sample data are provided and compared with data obtained using similar square wave techniques.
journal_name
Physiol Measjournal_title
Physiological measurementauthors
Searle A,Kirkup Ldoi
10.1088/0967-3334/20/1/008subject
Has Abstractpub_date
1999-02-01 00:00:00pages
103-14issue
1eissn
0967-3334issn
1361-6579journal_volume
20pub_type
杂志文章abstract::The increasing use of EIT in clinical research on severely ill lung patients requires a clarification of the influence of pathologic impedance distributions on the validity of the resulting tomograms. Significant accumulation of low-conducting air (e.g. pneumothorax or emphysema) or well-conducting liquid (e.g. haemat...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/27/5/S16
更新日期:2006-05-01 00:00:00
abstract:OBJECTIVE:Manganese (Mn) is a neurotoxin. However, the impact of elevated, chronic Mn exposure is not well understood, partially due to the lack of a cumulative exposure biomarker. To address this gap, our group developed a compact in vivo neutron activation analysis (IVNAA) system to quantify Mn concentration in bone ...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/1361-6579/aaa749
更新日期:2018-03-23 00:00:00
abstract::Alzheimer's disease (AD) is a degenerative disease which causes serious cognitive decline. Studies suggest that effective treatments for AD may be aided by the detection of the disease in its early stages, prior to extensive neuronal degeneration. In this paper, we propose a set of novel techniques which could help to...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/28/4/001
更新日期:2007-04-01 00:00:00
abstract::Nasal obstruction disturbs comfort during daytime, and sleep quality. Convenient objective assessment of nasal ventilation would be desirable. Therefore, we developed a technique for unobtrusive monitoring of bilateral nasal airflow. Nasal cannulae with separated left- and right-sided tubings were connected to two pre...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/26/1/007
更新日期:2005-02-01 00:00:00
abstract::Body surface potential maps recorded during catheter pace mapping can facilitate the localization of the site of origin of ventricular tachycardia. In this study, we investigated the value of a realistic computer model of the human ventricular myocardium in generating body surface potential maps as templates for ident...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/18/4/010
更新日期:1997-11-01 00:00:00
abstract::In this paper a description is given of the development, characterisation and first results of a thermal imaging device aimed at significantly reducing the incidence of diabetic foot ulceration (DFU). These devices will be used in three clinical centres and in two preliminary clinical trials. The first will be on heal...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/1361-6579/aa56b1
更新日期:2017-03-01 00:00:00
abstract::The pre-ejection period (PEP) has recently been described as a potential parameter for monitoring cardiac preload. This study further investigated the influence of changes in intravascular volume status and the application of positive end-expiratory pressure (PEEP) on the pre-ejection period. In ten pigs, ECG, arteria...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/26/6/012
更新日期:2005-12-01 00:00:00
abstract::The effects of mechanical stimulation on hemodynamics, such as due to mechanotransduction in vascular endothelial cells, have been widely discussed recently. We previously proposed a resonance model in which the arterial system is treated as a pressure-transmitting system, and suggested that the application of externa...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/27/2/004
更新日期:2006-02-01 00:00:00
abstract:OBJECTIVE:To investigate the effect of maternal hyperoxygenation on fetal heart rate (FHR) when applied for suspected fetal distress during the second stage of term labor. APPROACH:A single-center randomized controlled trial was conducted in a tertiary care hospital in The Netherlands. Participants were included durin...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/1361-6579/abc0b6
更新日期:2020-12-11 00:00:00
abstract::In this paper we present a method for recognising three fundamental movements of the human arm (reach and retrieve, lift cup to mouth, rotation of the arm) by determining the orientation of a tri-axial accelerometer located near the wrist. Our objective is to detect the occurrence of such movements performed with the ...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/35/9/1751
更新日期:2014-09-01 00:00:00
abstract::A method is described that accounts for multichannel brain field data (EEG) epochs, after transformation into the frequency domain, by a single oscillating dipole source in terms of phase angles. The method produces a potential distribution for each frequency point ('FFT dipole approximation'). These maps can be subje...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/14/4a/004
更新日期:1993-11-01 00:00:00
abstract::A time-varying parametric spectrum estimation method for analysing non-stationary heart rate variability signals is presented. As a case study, the dynamics of heart rate variability during an orthostatic test is examined. In this method, the non-stationary signal is first modelled with a time-varying autoregressive m...
journal_title:Physiological measurement
pub_type: 临床试验,杂志文章
doi:10.1088/0967-3334/27/3/002
更新日期:2006-03-01 00:00:00
abstract::Myoelectrical pattern classification is a crucial part in multi-functional prosthesis control. This paper investigates a discriminant Fourier-derived cepstrum (DFC) and feature-level post-processing (FLPP) to discriminate hand and wrist motions using the surface electromyographic signal. The Fourier-derived cepstrum t...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/30/12/008
更新日期:2009-12-01 00:00:00
abstract:OBJECTIVE:Brain waves vary between people. This work aims to improve automatic sleep staging for longitudinal sleep monitoring via personalization of algorithms based on individual characteristics extracted from sleep data recorded during the first night. APPROACH:As data from a single night are very small, thereby ma...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/1361-6579/ab921e
更新日期:2020-07-01 00:00:00
abstract::Electrical impedance tomography (EIT) is expected to become a valuable tool for monitoring mechanically ventilated patients due to its ability to continuously assess regional lung ventilation and aeration. Several sources of interference with EIT examinations exist in intensive care units (ICU). Our objectives are to ...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/32/12/F01
更新日期:2011-12-01 00:00:00
abstract::It has previously been shown that extreme changes in ambient air temperature can affect whole-body bioelectrical impedance. The purpose of this study was to determine if more moderate changes in ambient air temperature, such as those experienced in most laboratory settings, would also affect bioelectric impedance anal...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/25/1/011
更新日期:2004-02-01 00:00:00
abstract:OBJECTIVE:Metal exposures have been linked with many adverse health outcomes affecting nearly every system in the body. Exposure to metals has been tracked primarily using blood. Blood metal concentrations have drawbacks as biomarkers stemming from the metals' short biologic half-lives, shipping and storage requirement...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/1361-6579/aad947
更新日期:2018-08-31 00:00:00
abstract:OBJECTIVE:Though the mutual influence of cardiovascular and respiratory rhythms in healthy newborns has been documented, its full characterization is still pending. In general, the activity of many physiological subsystems has a well-expressed rhythmic character, and often an interdependency between physiological rhyth...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/1361-6579/aac553
更新日期:2018-06-19 00:00:00
abstract::The results of a preliminary clinical evaluation of a one-frequency electrical impedance tomography (EIT) system enabling static in vivo imaging are presented. The design of the measuring system and image reconstruction software are described. Thirty-one subjects were examined and divided into four clinical groups. Th...
journal_title:Physiological measurement
pub_type: 临床试验,杂志文章
doi:10.1088/0967-3334/23/1/304
更新日期:2002-02-01 00:00:00
abstract::Virtual shunt describes the overall loss of O2 content between the alveolar gas and arterial blood. Clinicians indirectly estimate the magnitude of the virtual shunt by monitoring peripheral blood oxygen saturation (SpO2) using non-invasive pulse oximetry. An inherent limitation of this method is the variable precisio...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/36/5/967
更新日期:2015-05-01 00:00:00
abstract::A multi-frequency electrical impedance tomography system for cardiopulmonary monitoring has been designed with specialized digital signal processors developed primarily for the telecommunications sector. The system consists of two modules: a scan-head and a base-station. The scan-head, located close to the patient's t...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/30/6/S04
更新日期:2009-06-01 00:00:00
abstract::Pulmonary blood volume increase during systole was measured in patients by analysing chest images obtained during ECG gated radionuclide angiography examination. The difference in the total radiation counts between systole and diastole in regions of interest, which included the lungs and the left ventricle, was measur...
journal_title:Physiological measurement
pub_type: 临床试验,杂志文章
doi:10.1088/0967-3334/15/4/010
更新日期:1994-11-01 00:00:00
abstract::Linear methods of reconstruction play an important role in medical electrical impedance tomography (EIT) and there is a wide variety of algorithms based on several assumptions. With the Graz consensus reconstruction algorithm for EIT (GREIT), a novel linear reconstruction algorithm as well as a standardized framework ...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/36/6/1161
更新日期:2015-06-01 00:00:00
abstract::The state-dependent portion of cardio-vagal baroreflex control is called baroreflex hyteresis: we observe hysteresis when RR interval and carotid diameter depend on both the direction and value of arterial pressure. The elasticity of arterial walls, as well as the responsiveness of central command reset controls the r...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/31/6/009
更新日期:2010-06-01 00:00:00
abstract::Electroneurograms (ENGs) from the vagus nerve (VN), the splanchnic nerve (SN) and the pancreatic nerve (PN) innervating the pancreas of a dog, were recorded with chronically implanted 33-electrode spiral cuffs (cuff) before and after the pancreas were stimulated with intravenously (i.v.) administered glucose. In the c...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/23/4/309
更新日期:2002-11-01 00:00:00
abstract::Idiopathic normal pressure hydrocephalus (INPH) patients have a disturbance in the dynamics of the cerebrospinal fluid (CSF) system. The outflow conductance, C, of the CSF system has been suggested to be prognostic for positive outcome after treatment with a CSF shunt. All current methods for estimation of C have draw...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/28/11/003
更新日期:2007-11-01 00:00:00
abstract::During voluntary contractions in humans, the subcutaneous tissues between surface electrodes and active motor units have been shown to attenuate surface electromyographic (EMG) signal amplitude. The purpose of this investigation was to examine the relationship between adipose tissue thickness and the electromechnical ...
journal_title:Physiological measurement
pub_type: 临床试验,杂志文章
doi:10.1088/0967-3334/37/3/418
更新日期:2016-03-01 00:00:00
abstract:OBJECTIVE:PaCO2 affects cerebral blood flow (CBF) and its regulatory mechanisms, but the effects of CO2 measurement technique on cerebrovascular parameters are unknown. In order to determine if the two most commonly used approaches, face mask (FM) or nasal cannulae (NC), are interchangeable or not, we tested the hypoth...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/1361-6579/aa6f9f
更新日期:2017-06-22 00:00:00
abstract::High-frequency percussive ventilation (HFPV) may be defined as flow-regulated time-cycled ventilation that creates controlled pressure and delivers a series of high-frequency subtidal volumes in combination with low-frequency breathing cycles. In recent years, the usefulness of HFPV has been clinically assessed as an ...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/32/6/002
更新日期:2011-06-01 00:00:00
abstract::Conventional bioimpedance spectrometers measure resistance and reactance over a range of frequencies and, by application of a mathematical model for an equivalent circuit (the Cole model), estimate resistance at zero and infinite frequencies. Fitting of the experimental data to the model is accomplished by iterative, ...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/27/9/007
更新日期:2006-09-01 00:00:00