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Biomedical engineering and bibliometric indices for scientific qualityEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Content Type Journal ArticleCategory EditorialDOI 10.1007/s11517-009-0546-9Authors Jos A. E. Spaan, University of Amsterdam Department Biomedical Engineering and Physics, Academic Medical Center Amsterdam The Netherlands Journal Medical and Biological Engineering and ComputingOnline ISSN 1741-0444Print ISSN 0140-0118 (Source: Medical and Biological Engineering and Computing)
Source: Medical and Biological Engineering and Computing - November 12, 2009 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: journals

First in vivo assessment of “Outwalk”: a novel protocol for clinical gait analysis based on inertial and magnetic sensorsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract A protocol named “Outwalk” was recently proposed to measure the thorax–pelvis and lower-limb kinematics during gait in free-living conditions, by means of an inertial and magnetic measurement system (IMMS). The aim of this study was to validate Outwalk on four healthy subjects when it is used in combination with a specific IMMS (Xsens Technologies, NL), against a reference protocol (CAST) and measurement system (optoelectronic system; Vicon, Oxford Metrics Group, UK). For this purpose, we developed an original approach based on three tests, which allowed to separately investigate: (1) the cons...
Source: Medical and Biological Engineering and Computing - November 12, 2009 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: journals

‘Outwalk’: a protocol for clinical gait analysis based on inertial and magnetic sensorsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract A protocol named Outwalk was developed to easily measure the thorax–pelvis and lower-limb 3D kinematics on children with cerebral palsy (CP) and amputees during gait in free-living conditions, by means of an Inertial and Magnetic Measurement System (IMMS). Outwalk defines the anatomical/functional coordinate systems (CS) for each body segment through three steps: (1) positioning the sensing units (SUs) of the IMMS on the subjects’ thorax, pelvis, thighs, shanks and feet, following simple rules; (2) computing the orientation of the mean flexion–extension axis of the knees; (3) measuring the SUs...
Source: Medical and Biological Engineering and Computing - November 12, 2009 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: journals

Stopping mechanism for capsule endoscope using electrical stimulusEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract An ingestible capsule, which has the ability to stop at certain locations in the small intestine, was designed and implemented to monitor intestinal diseases. The proposed capsule can contract the small intestine by using electrical stimuli; this contraction causes the capsule to stop when the maximum static frictional force (MSFF) is larger than the force of natural peristalsis. In vitro experiments were carried out to verify the feasibility of the capsule, and the results showed that the capsule was successfully stopped in the small intestine. Various electrodes and electrical stimulus parame...
Source: Medical and Biological Engineering and Computing - November 12, 2009 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: journals

Electroencephalographic spectral asymmetry index for detection of depressionEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This study is aimed to compare sensitivity of different electroencephalographic (EEG) indicators for detection of depression. The novel EEG spectral asymmetry index (SASI) was introduced based on balance between the powers of two special EEG frequency bands selected lower and higher of the EEG spectrum maximum and excluding the central frequency from the calculations. The efficiency of the SASI was compared to the traditional EEG inter-hemispheric asymmetry and coherence methods. EEG recordings were carried out on groups of depressive and healthy subjects of 18 female volunteers each. The resting eight-channel EEG was...
Source: Medical and Biological Engineering and Computing - November 12, 2009 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: journals

Composition of the pericellular matrix modulates the deformation behaviour of chondrocytes in articular cartilage under static loadingEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract The aim was to assess the role of the composition changes in the pericellular matrix (PCM) for the chondrocyte deformation. For that, a three-dimensional finite element model with depth-dependent collagen density, fluid fraction, fixed charge density and collagen architecture, including parallel planes representing the split-lines, was created to model the extracellular matrix (ECM). The PCM was constructed similarly as the ECM, but the collagen fibrils were oriented parallel to the chondrocyte surfaces. The chondrocytes were modelled as poroelastic with swelling properties. Deformation behaviour of...
Source: Medical and Biological Engineering and Computing - November 7, 2009 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: journals

Computer-assisted quantification of lung tumors in respiratory gated PET/CT images: phantom studyEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract A computer-aided method was developed to automatically localize tumors in lung PET images of discrete bins within the breathing cycle, followed by an algorithm that registers all the information of a complete respiratory cycle into a single reference bin. Four registration/integration algorithms: Centroid Based, Intensity Based, Rigid Body, and Optical Flow registration were compared as well as two registration schemes: Direct scheme and Successive scheme. Validation was demonstrated by conducting experiments with the computerized 4D NCAT phantom and with a dynamic lung–chest phantom imaged using ...
Source: Medical and Biological Engineering and Computing - November 5, 2009 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: journals

Theoretical evaluation of a simple cooling pad for inducing hypothermia in the spinal cord following traumatic injuryEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract The Pennes bioheat equation and finite element method (FEM) are used to solve for the temperature distributions in the spinal cord and cerebrospinal fluid (CSF) during 30 min of cooling for spinal cord injury (SCI) patients. The average CSF and spinal cord temperatures are reduced by 3.48 and 2.72°C, respectively. The 100-mm wide pad provides the desired cooling and uses the least amount of material. The presence of zero-average CSF oscillation under normal conditions decreases the cooling extent in the spinal cord due to the introduction of warm CSF surrounding the spinal cord. The temperatur...
Source: Medical and Biological Engineering and Computing - November 4, 2009 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: journals

Unsupervised movement onset detection from EEG recorded during self-paced real hand movementEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This article presents an unsupervised method for movement onset detection from electroencephalography (EEG) signals recorded during self-paced real hand movement. A Gaussian Mixture Model (GMM) is used to model the movement and idle-related EEG data. The GMM built along with appropriate classification and post processing methods are used to detect movement onsets using self-paced EEG signals recorded from five subjects, achieving True–False rate difference between 63 and 98%. The results show significant performance enhancement using the proposed unsupervised method, both in the sample-by-sample classification accura...
Source: Medical and Biological Engineering and Computing - November 4, 2009 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: journals

Effectiveness of thigh-to-thigh current path for the measurement of abdominal fat in bioelectrical impedance analysisEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We present a new method measuring body impedance using a thigh-to-thigh current path, which can reflect the abdominal fat portion more sensitively and can be conveniently applied during the daily use on a toilet seat. Two pairs of electrodes were installed on a toilet seat to provide current and to permit voltage measurement through a thigh-to-thigh current path. The effectiveness of the method was compared with conventional foot-to-foot and hand-to-foot current paths by simulation and by experiments referenced to computed tomography (CT) image analysis. Body impedance using three different current paths was measured,...
Source: Medical and Biological Engineering and Computing - November 4, 2009 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: journals

Forward modelling of magnetic induction tomography: a sensitivity study for detecting haemorrhagic cerebral strokeEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract For a magnetic induction tomography (MIT) system operating at 10 MHz, the signals produced by a haemorrhagic cerebral stroke were computed using an anatomically realistic, multi-layer, finite element (FE) head model comprising 12 tissues. The eddy-current problem was approximated using the commercial FE package, Comsol Multiphysics, and the numerical techniques employed were validated using a benchmark test. Mesh convergence for the head model was investigated for first- and second-order elements. MIT signals were computed for strokes of different sizes and locations in the brain to judge the s...
Source: Medical and Biological Engineering and Computing - October 15, 2009 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: journals

Control of triceps surae stimulation based on shank orientation using a uniaxial gyroscope during gaitEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This article presents a stimulation control method using a uniaxial gyroscope measuring angular velocity of the shank in the sagittal plane, to control functional electrical stimulation of the triceps surae to improve push-off of stroke subjects during gait. The algorithm is triggered during each swing phase of gait when the angular velocity of the shank is relatively high. Subsequently, the start of the stance phase is detected by a change of sign of the gyroscope signal at approximately the same time as heel strike. Stimulation is triggered when the shank angle reaches a preset value since the beginning of stance. Th...
Source: Medical and Biological Engineering and Computing - October 14, 2009 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: journals

Nonlinear finite element analysis of the vibration characteristics of the maxillary central incisor related to periodontal attachmentEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract The vibration characteristics of a maxillary central incisor were investigated by using the finite element method (FEM) according to nonlinear behavior of the human periodontal ligament (PDL). The effect of alveolar bone loss was also studied to obtain the relationship between the vibration property of the tooth in the periodontal system and the level of periodontal attachment for assessing the condition of periodontium. Three-dimensional (3D) finite element model of the tooth was constructed using CT image-reconstruction, and the elastic face foundation constraint was applied to the surface of the ...
Source: Medical and Biological Engineering and Computing - October 14, 2009 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: journals

Right atrial organization and wavefront analysis in atrial fibrillationEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract The purpose of this study was to develop techniques to quantify the propagation pattern of the electrical activation during atrial fibrillation (AF) along a one-dimensional catheter. Taking intra-atrial signal organization aspects into account, the atrial activations are detected and combined into wavefronts. Parameters describing wavefront consistency and activation order along the catheter are defined, and the relationship of wavefront consistency to body surface parameters, namely AF frequency and exponential decay, is investigated. The database consisted of 26 10-s recordings from patients durin...
Source: Medical and Biological Engineering and Computing - October 14, 2009 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: journals

Computerised electronic foetal heart rate monitoring in labour: automated contraction identificationEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We describe here a novel technique for automated detection of uterus contractions. In addition, we present a comparison of the new method with four other computerised approaches. During training, OxSys achieved sensitivity above 95% and positive predictive value (PPV) of up to 90% for traces of good quality. During testing, OxSys achieved sensitivity = 87% and PPV = 75%. For comparison, a second clinical expert obtained sensitivity = 93% and PPV = 80%, and all other computerised approaches achieved lower values. It was concluded that the proposed method can be employed with confi...
Source: Medical and Biological Engineering and Computing - October 14, 2009 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: journals

A procedure for evaluation of non-invasive blood pressure simulatorsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract Non-invasive blood pressure (NIBP) simulators are used in clinical environment for quick checks of blood pressure monitors as a part of technical maintenance and health-care quality assurance system. They are also included in various tests within the procedures for testing NIBP monitors. In practice simulators are often subject to mechanical and electromagnetic shocks which could effect their measuring function. Our objective was to design a procedure for testing the reliability and quality of simulators in order to ensure reliable testing of NIBP monitors. Procedure for evaluation of NIBP simulator...
Source: Medical and Biological Engineering and Computing - October 13, 2009 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: journals

The Nightingale Award 2008Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Content Type Journal ArticleCategory EditorialDOI 10.1007/s11517-009-0536-yAuthors Jos A. E. Spaan, Academic Medical Center, University of Amsterdam Meibergdreef 9 1105 Amsterdam The Netherlands Journal Medical and Biological Engineering and ComputingOnline ISSN 1741-0444Print ISSN 0140-0118 (Source: Medical and Biological Engineering and Computing)
Source: Medical and Biological Engineering and Computing - October 13, 2009 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: journals

Multilayer imaging and compositional analysis of human male breast by laser reflectometry and Monte Carlo simulationEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The objective of this work is to study the point-to-point compositional variation of male breast tissues as this site has been prone to cancer development. The normalized backscattered intensity (NBI) profiles at various locations of human chest region of five subjects by multi-probe laser reflectometer are obtained. Based on these data the images of tissue composition, showing the point-to-point changes at various depths from the tissue surface, are reconstructed. The analysis of data shows that the maximum NBI variation is at the pectoralis major muscle and minimum variation is observed at the sternum. The optical p...
Source: Medical and Biological Engineering and Computing - October 10, 2009 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: journals

Evaluating the accuracy of wear formulae for acetabular cup linersEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This study proposes two methods for exploring the wear volume of a worn liner. The first method is a numerical method, in which SolidWorks® software is used to create models of the worn out regions of liners at various wear directions and depths. The second method is an experimental one, in which a machining center is used to mill polyoxymethylene to manufacture worn and unworn liner models, then the volumes of the models are measured. The results show that the SolidWorks® software is a good tool for presenting the wear pattern and volume of a worn liner. The formula provided by Ilchmann is the most suitable for comp...
Source: Medical and Biological Engineering and Computing - October 10, 2009 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: journals

Frequency-domain reconstruction of signals in electrical bioimpedance spectroscopyEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract The use of an amplitude/phase retrieval algorithm in electrical bioimpedance spectroscopy (EIS) that allows a new technique to reconstruct the impedance spectrum in the frequency-domain is reported. To the authors’ knowledge this is the first time the proposed algorithm has been used to calculate the modulus or phase of a bioimpedance in EIS from one of these two experimentally obtained parameters. The algorithmic technique is demonstrated in EIS, when wide-bandwidth amplifiers, phase-detectors, and high speed converters determine spectra over frequencies up to 500 kHz at isolated points in t...
Source: Medical and Biological Engineering and Computing - October 10, 2009 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: journals

Time domain algorithm for accelerated determination of the first order moment of photo current fluctuations in high speed laser Doppler perfusion imagingEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This study shows that the TD-algorithm is twice as fast as the FFT-algorithm without loss of accuracy. Compared to FFT, the TD-algorithm is efficient in terms of processor time, memory usage and data transport. Content Type Journal ArticleCategory Original ArticleDOI 10.1007/s11517-009-0537-xAuthors Matthijs Draijer, University of Twente Biophysical Engineering Group, MIRA Institute for Biomedical Technology and Technical Medicine Enschede The NetherlandsErwin Hondebrink, University of Twente Biophysical Engineering Group, MIRA Institute for Biomedical Technology and Technical Medicine Enschede The NetherlandsTon van...
Source: Medical and Biological Engineering and Computing - October 10, 2009 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: journals

Transient and steady state estimation of human oxygen uptake based on noninvasive portable sensor measurementsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract The main motivation of this study is to establish an ambulatory cardio-respiratory analysis system for the monitoring and evaluation of exercise and regular daily physical activity. We explored the estimation of oxygen uptake by using noninvasive portable sensors. These sensors are easy to use but may suffer from malfunctions under free living environments. A promising solution is to combine sensors with different measuring mechanisms to improve both reliability and accuracy of the estimation results. For this purpose, we selected a wireless heart rate sensor and a tri-axial accelerometer to form a ...
Source: Medical and Biological Engineering and Computing - October 1, 2009 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: journals

Upper limb muscle forces during a simple reach-to-grasp movement: a comparative studyEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract Muscle force knowledge during reaching is an important research field and tools development for measuring those forces is a challenging task, especially for clinical routines. The purpose of this study was, during a simple reach-to-grasp movement, to compare forces estimation from a Hill-type model and from the EMG-to-Force Processing (EFP) method. Ten healthy male volunteers were tested. Surface EMG signals were recorded from deltoid scapular, deltoid clavicular, triceps brachii, and biceps brachii. Ten repeated measures of right upper limb kinematics had been recorded. Three reaching distances wer...
Source: Medical and Biological Engineering and Computing - September 28, 2009 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: journals

Helical axis calculation based on Burmester theory: experimental comparison with traditional techniques for human tibiotalar joint motionEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract In prosthetics and orthotics design, it is sometimes necessary to approximate the multiaxial motion of several human joints to a simple rotation about a single fixed axis. A new technique for the calculation of this axis is proposed, originally based on Burmester’s theory. This was compared with traditional approaches based on the mean and finite helical axes. The three techniques were assessed by relevant optimal axis estimation in in vitro measurements of tibiotalar joint motion. A standard jig and radiostereometry were used in two anatomical specimens to obtain accurate measurements of joi...
Source: Medical and Biological Engineering and Computing - September 17, 2009 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: journals

On the EEG/MEG forward problem solution for distributed cortical sourcesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, we analyze the different errors induced by this approximation on the EEG/MEG forward problem. Our results show that in order to obtain more accurate solutions of the forward problems with the multiple dipoles approximation, the moments of the dipoles should be weighted by the area of the surrounding triangles, or using an alternative approximation of the primary current as a constant or linearly varying current density over plane triangular elements of the cortical surface tessellation. This should be taken into account when computing the lead field matrix for solving the EEG/MEG inverse problem in brai...
Source: Medical and Biological Engineering and Computing - September 17, 2009 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: journals

Identification of task parameters from movement-related cortical potentialsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract The study investigates the accuracy in discriminating rate of torque development (RTD) and target torque (TT) (task parameters) from electroencephalography (EEG) signals generated during imaginary motor tasks. Signals were acquired from nine healthy subjects during four imaginary isometric plantar-flexions of the right foot involving two RTDs (ballistic and moderate) and two TTs (30 and 60% of the maximal voluntary contraction torque), each repeated 60 times in random order. The single-trial EEG traces were classified with a pattern recognition approach based on wavelet coefficients as features and ...
Source: Medical and Biological Engineering and Computing - September 17, 2009 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: journals

Non-invasive atrial fibrillation organization follow-up under successive attempts of electrical cardioversionEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract The development of non-invasive tools able to provide valuable information about the effectiveness of a shock in external electrical cardioversion (ECV) is clinically relevant to enhance these protocols in the treatment of atrial fibrillation (AF). The present contribution analyzes the ability of a non-linear regularity index, such as sample entropy (SampEn), to follow-up non-invasively AF organization under successive attempts of ECV and to predict the effectiveness of every single shock. To this respect, the atrial activity (AA) preceding each delivered shock was extracted by using a QRST cancella...
Source: Medical and Biological Engineering and Computing - September 16, 2009 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: journals

Antepartum non-invasive evaluation of opening and closing timings of the cardiac valves in fetal cardiac cycleEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, we propose a non-invasive algorithm to recognize the timings of fetal cardiac events on the basis of analysis of fetal ECG (FECG) and Doppler ultrasound signals. Multiresolution wavelet analysis enabled the frequency contents of the Doppler signals to be linked to the opening (o) and closing (c) of the heart’s valves (Aortic (A) and Mitral (M)). M-mode, B-mode and pulsed Doppler ultrasound were used to verify the timings of opening and closure of these valves. In normal fetuses, the time intervals from Q-wave of QRS complex of FECG to opening and closing of aortic valve, i.e., Q-Ao and Q-Ac were found ...
Source: Medical and Biological Engineering and Computing - August 27, 2009 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: journals

Computer-aided analysis of gait rhythm fluctuations in amyotrophic lateral sclerosisEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract Deterioration of motor neurons due to amyotrophic lateral sclerosis (ALS) would affect the strides from one gait cycle to the next. Computer-assisted techniques are useful for gait analysis, and also have high potential in quantitatively monitoring the pathological progression. In this paper, we applied the signal turns count method to measure the fluctuations in the swing-interval time series recorded from 16 healthy control subjects and 13 patients with ALS. The swing-interval turns count (SWITC) parameter derived with the threshold of 0.06 s presented a significant difference (p <&nb...
Source: Medical and Biological Engineering and Computing - August 25, 2009 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: journals

Alterations of human electroencephalographic activity caused by multiple extremely low frequency magnetic field exposuresEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This study aims at extending our ELF pilot study to investigate whether MF exposures at ELF in series from 50, 16.66, 13, 10, 8.33 to 4 Hz could alter relative power within the corresponding EEG bands. 33 human subjects were tested under a double-blind and counter-balanced conditions. The multiple repeated three-way analysis of variance (ANOVA) mixed design (within and between-subject) analysis was employed followed by post-hoc t-tests and Bonferroni alpha-correction. The results from this study have shown that narrow alpha1 (7.5–9.5 Hz) and alpha2 (9–11 Hz) bands, associated with 8.33 and 10 Hz MF e...
Source: Medical and Biological Engineering and Computing - August 25, 2009 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: journals

Comparative evaluation of motor unit architecture modelsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We present a statistical evaluation and comparison of the simulation outcomes of nine different motor unit architecture modeling approaches, which derive from combinations of four motor unit territory placement algorithms with two innervation pattern algorithms (one of the combinations allows for a double approach). We test how well the outcomes of these models agree with well-established physiological principles. Our results show that algorithms based on independent and uniformly distributed territory placement always lead to an unwanted edge effect consisting in a decay of the number of overlapping motor unit territo...
Source: Medical and Biological Engineering and Computing - August 25, 2009 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: journals

A state transition-based method for quantifying EEG sleep fragmentationEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract Sleep fragmentation is the predominant factor causing excessive daytime sleepiness in diseases such as sleep apnea and periodic leg movement syndrome. The reference standard for quantifying sleep fragmentation is the arousal index (ArI), which is defined as the average number of arousals per hour of sleep. Arousal scoring is tedious and subjective resulting in considerable inter- and intra-rater variability. Moreover, ArI is only weakly correlated with other indicators of sleep fragmentation such as the total sleep time (TST) and the sleep efficiency (SE). This introduces consistency problems, makin...
Source: Medical and Biological Engineering and Computing - August 25, 2009 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: journals

Adaptive windowing for gait phase discrimination in Parkinsonian gait using 3-axis acceleration signalsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract In order to robustly analyze the gait of Parkinson’s disease (PD) patients, a new gait phase discrimination method was developed for analyzing the three-axis accelerations of the ankle during walking. The magnitude of acceleration was compared with the lowpass-filtered signal of itself and pseudo foot-flat phases were determined. Four narrow windows were made sequentially and adaptively from the pseudo foot-flat phases. Each window contained a characteristic peak that discriminated the gait phases. From these windows, the initial contact (IC) point and end contact (EC) point were determined by fin...
Source: Medical and Biological Engineering and Computing - August 20, 2009 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: journals

List of ReviewersEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Content Type Journal ArticleCategory List of ReviewersDOI 10.1007/s11517-009-0520-6 Journal Medical and Biological Engineering and ComputingOnline ISSN 1741-0444Print ISSN 0140-0118 (Source: Medical and Biological Engineering and Computing)
Source: Medical and Biological Engineering and Computing - August 11, 2009 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: journals

Three-dimensional ray tracing through curvilinear interfaces with application to laser Doppler anemometry in a blood analogue fluidEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract Prediction of the effects of refractive index (RI) mismatch on laser Doppler anemometer (LDA) measurements within a curvilinear cavity (an artificial ventricle) was achieved by developing a general technique for modelling the paths of the convergent beams of the LDA system using 3D vector geometry. Validated by ray tracing through CAD drawings, the predicted maximum tolerance in RI between the solid model and the working fluid was ± 0.0005, equivalent to focusing errors commensurate with the geometric and alignment uncertainties associated with the flow model and the LDA arrangement. This...
Source: Medical and Biological Engineering and Computing - August 11, 2009 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: journals

Computer simulation for the optimization of instrumentation strategies in adolescent idiopathic scoliosisEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This study aims to develop a method to define the optimal surgical instrumentation strategy using a computer model implemented in a spine surgery simulator (S3). A total of 702 different strategies were simulated on a scoliotic patient using S3. Each configuration was assessed using objective functions that represented different correction objectives. Twelve geometric parameters were used in the three anatomic planes and mobility, and their relative weights were defined by a spine surgeon according to his objectives for correction of scoliosis. Six instrumentation parameters were manipulated in a uniform experimental d...
Source: Medical and Biological Engineering and Computing - August 11, 2009 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: journals

Acceleration of cardiac tissue simulation with graphic processing unitsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract In this technical note we show the promise of using graphic processing units (GPUs) to accelerate simulations of electrical wave propagation in cardiac tissue, one of the more demanding computational problems in cardiology. We have found that the computational speed of two-dimensional (2D) tissue simulations with a single commercially available GPU is about 30 times faster than with a single 2.0 GHz Advanced Micro Devices (AMD) Opteron processor. We have also simulated wave conduction in the three-dimensional (3D) anatomic heart with GPUs where we found the computational speed with a single GPU...
Source: Medical and Biological Engineering and Computing - August 4, 2009 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: journals

Novel electrode–skin interface for breast electrical impedance scanningEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract The high false-positive rate in clinical examinations limits the application of electrical impedance scanning (EIS) on breast cancer detection. One of the reasons is the non-uniform electrode–skin interface, which induces the ‘contact artifact’ in the results. To decrease the ‘contact artifact’, we designed a novel disposable electrode–skin interface [cotton fine grid thin layer (CFGTL)-interface], which is 0.2-mm thick and has a conductivity similar to that of normal breast tissue. The performance of the CFGTL-interface was evaluated by comparing it with the ultrasound gel interface gen...
Source: Medical and Biological Engineering and Computing - August 4, 2009 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: journals

Modeling effects of axial extension on arterial growth and remodelingEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract Diverse mechanical perturbations elicit arterial growth and remodeling responses that appear to optimize structure and function so as to promote mechanical homeostasis. For example, it is well known that functional adaptations to sustained changes in transmural pressure and blood flow primarily affect wall thickness and caliber to restore circumferential and wall shear stresses toward normal. More recently, however, it has been shown that changes in axial extension similarly prompt dramatic cell and matrix reorganization and turnover, resulting in marked changes in unloaded geometry and mechanical b...
Source: Medical and Biological Engineering and Computing - July 31, 2009 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: journals

Effects of compressive residual stress on the morphologic changes of fibroblastsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, by using an injection-molded method combined with photoelastic technology, we developed residual stress gradient-controlled poly-l-lactide discs. After culturing NIH-3T3 fibroblasts on the stress gradient substrate, the cell distributions for high- and low-stress regions were measured and compared. Our results showed that there were significantly more cells in the low-compressive stress region relative to their high-stress analogs (p < 0.05). In addition, NIH-3T3 fibroblasts in the low-compressive stress region expressed more abundant extensive filopodia. These findings provide greater insig...
Source: Medical and Biological Engineering and Computing - July 28, 2009 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: journals

Acknowledgment of Reviewer performance in 2008Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Content Type Journal ArticleCategory EditorialDOI 10.1007/s11517-009-0515-3Authors Jos A. E. Spaan, Amsterdam The Netherlands Journal Medical and Biological Engineering and ComputingOnline ISSN 1741-0444Print ISSN 0140-0118 (Source: Medical and Biological Engineering and Computing)
Source: Medical and Biological Engineering and Computing - July 28, 2009 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: journals

An acoustical respiratory phase segmentation algorithm using genetic approachEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract This paper proposes a robust and fully automated respiratory phase segmentation method using single channel tracheal breath sounds (TBS) recordings of different types. The estimated number of respiratory segments in a TBS signal is firstly obtained based on noise estimation and nonlinear mapping. Respiratory phase boundaries are then located through the generations of multi-population genetic algorithm by introducing a new evaluation function based on sample entropy (SampEn) and a heterogeneity measure. The performance of the proposed method is analyzed for single channel TBS recordings of various t...
Source: Medical and Biological Engineering and Computing - July 28, 2009 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: journals

Special issue on microbubbles: from contrast enhancement to cancer therapyEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Content Type Journal ArticleCategory EditorialDOI 10.1007/s11517-009-0510-8Authors Eleanor Stride, University College London Department of Mechanical Engineering Torrington Place London WC1E 7JE UKMohan Edirisinghe, University College London Department of Mechanical Engineering Torrington Place London WC1E 7JE UK Journal Medical and Biological Engineering and ComputingOnline ISSN 1741-0444Print ISSN 0140-0118 (Source: Medical and Biological Engineering and Computing)
Source: Medical and Biological Engineering and Computing - July 28, 2009 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: journals

A microprocessor-controlled tracheal insufflation-assisted total liquid ventilation systemEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract A prototype time cycled, constant volume, closed circuit perfluorocarbon (PFC) total liquid ventilator system is described. The system utilizes microcontroller-driven display and master control boards, gear motor pumps, and three-way solenoid valves to direct flow. A constant tidal volume and functional residual capacity (FRC) are maintained with feedback control using end-expiratory and end-inspiratory stop-flow pressures. The system can also provide a unique continuous perfusion (bias flow, tracheal insufflation) through one lumen of a double-lumen endotracheal catheter to increase washout of dead...
Source: Medical and Biological Engineering and Computing - July 25, 2009 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: journals

Safety and bio-effects of ultrasound contrast agentsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract The use of gas-filled microbubbles as ultrasound contrast agents raises potential safety concerns for diagnostic ultrasound imaging. A number of biological effects have been seen in experimental systems, including the induction of physiological response to cardiac exposures (premature ventricular contractions) and damage at a microvascular level (microvascular rupture and petechial haemorrhage). The literature indicates that a mechanical index (MI) of 0.4 represents the threshold above which microvascular bio-effects are seen in in vivo studies. Above this value, the extent of biological effects app...
Source: Medical and Biological Engineering and Computing - July 13, 2009 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: journals

Acceleration of FEM-based transfer matrix computation for forward and inverse problems of electrocardiographyEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract The distributions of transmembrane voltage (TMV) within the cardiac tissue are linearly connected with the patient’s body surface potential maps (BSPMs) at every time instant. The matrix describing the relation between the respective distributions is referred to as the transfer matrix. This matrix can be employed to carry out forward calculations in order to find the BSPM for any given distribution of TMV inside the heart. Its inverse can be used to reconstruct the cardiac activity non-invasively, which can be an important diagnostic tool in the clinical practice.The computation of this matrix usi...
Source: Medical and Biological Engineering and Computing - July 10, 2009 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: journals

Regression analysis for peak designation in pulsatile pressure signalsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract Following recent studies, the automatic analysis of intracranial pressure (ICP) pulses appears to be a promising tool for forecasting critical intracranial and cerebrovascular pathophysiological variations during the management of many disorders. A pulse analysis framework has been recently developed to automatically extract morphological features of ICP pulses. The algorithm is able to enhance the quality of ICP signals, to segment ICP pulses, and to designate the locations of the three ICP sub-peaks in a pulse. This paper extends this algorithm by utilizing machine learning techniques to replace G...
Source: Medical and Biological Engineering and Computing - July 6, 2009 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: journals

Non-contact determination of parasympathetic activation induced by a full stomach using microwave radarEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract In order to evaluate parasympathetic activation which causes driving errors, without placing any burden on the monitored individuals, we conducted a non-contact parasympathetic activation monitoring through the back of a chair using a compact 24-GHz microwave-radar. We measured the high-frequency (HF, 0.15–0.4 Hz) power spectrum of heart rate variability (HRV) which reflects parasympathetic activation, induced by a full stomach. All participants had a large all-you-can-eat meal with beverages for lunch within 20 min. Before and after the large meals for durations of 10 min, the non-...
Source: Medical and Biological Engineering and Computing - July 6, 2009 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: journals

Activating function of needle electrodes in anisotropic tissueEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We present an analytical solution for the electrical potential and activating function (AF) established by cylindrical needle electrodes in anisotropic tissue. We compare this activating function to (1) AF computed assuming line-source electrodes and (2) AF computed using a finite element program. The results show that when the fiber is two needle diameters away from the electrodes, the maximum of the AF for needle electrodes is 1.43-times larger than for line-source electrodes, which results in lower thresholds for stimulation and electroporation. Therefore, for fibers that are close to the stimulating electrodes, on...
Source: Medical and Biological Engineering and Computing - July 6, 2009 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: journals

The optimal linear transformation-based fMRI feature space analysisEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract This paper proposes a method of extending the optimal linear transformation (OLT), an image analysis technique of feature space, from magnetic resonance imaging (MRI) to functional magnetic resonance imaging (fMRI) so as to improve the activation detection performance over conventional approaches of fMRI analysis. The method was: (1) ideal hemodynamic responses for different stimuli were generated by convolving the theoretical hemodynamic response model with the stimulus timing, (2) considering the ideal hemodynamic responses as hypothetical signature vectors for different activity patterns of inter...
Source: Medical and Biological Engineering and Computing - June 20, 2009 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: journals