Biomedical Engineering Research This is an OPML file. It can be used to export all the MedWorm RSS feeds on this topic into your personal RSS reader (usually you have to save this file to your own computer before clicking on an Import OPML command in your own feed reader to upload the file which will then import all the feeds) or it can be used by webmasters to integrate MedWorm feeds with their own website. This is an RSS file. You can use it to subscribe to this data in your favourite RSS reader, such as GoogleReader, or to display this data on your own website or blog. Subscribe to this data using MyMedWorm.Subscribe to this data using GoogleReader.Subscribe to this data using Bloglines.Subscribe to this data using MyYahoo.

This page shows you the most recent publications within this specialty of the MedWorm directory. This is page number 33.

Carbachol-Induced Volume Adaptation in Mouse Bladder and Length Adaptation via Rhythmic Contraction in Rabbit Detrusor.
Abstract The length-tension (L-T) relationships in rabbit detrusor smooth muscle (DSM) are similar to those in vascular and airway smooth muscles and exhibit short-term length adaptation characterized by L-T curves that shift along the length axis as a function of activation and strain history. In contrast to skeletal muscle, the length-active tension (L-T (a)) curve for rabbit DSM strips does not have a unique peak tension value with a single ascending and descending limb. Instead, DSM can exhibit multiple ascending and descending limbs, and repeated KCl-induced contractions at a particular muscle length...
Source: Annals of Biomedical Engineering - May 22, 2012 Category: Biomedical Engineering Authors: Speich JE, Wilson CW, Almasri AM, Southern JB, Klausner AP, Ratz PH Tags: Ann Biomed Eng Source Type: research

Fabrication, Characterization and In Vitro Evaluation of Aligned PLGA-PCL Nanofibers for Neural Regeneration.
In this study, we have designed and developed a collector to obtain aligned nanofibers of PLGA-PCL. The average diameter of the fibers obtained is 230 ± 63 nm and the alignment of fibers is quantified by calculating relative angle of each fiber. The tensile strength, porosity, contact angle, and biodegradation of the uniaxial PLGA-PCL nanofibers are measured and compared with the corresponding random fibers. Pore size, Young's modulus, and degradation of the aligned scaffold are significantly lesser than random fibers (p < 0.05). The in vitro cell adhesion and proliferation of Schwann cells on the aligned nanofibe...
Source: Annals of Biomedical Engineering - May 22, 2012 Category: Biomedical Engineering Authors: Subramanian A, Krishnan UM, Sethuraman S Tags: Ann Biomed Eng Source Type: research

Toward Mechanical Systems Biology in Bone.
Abstract Cyclic mechanical loading is perhaps the most important physiological factor regulating bone mass and shape in a way which balances optimal strength with minimal weight. This bone adaptation process spans multiple length and time scales. Forces resulting from physiological exercise at the organ scale are sensed at the cellular scale by osteocytes, which reside inside the bone matrix. Via biochemical pathways, osteocytes orchestrate the local remodeling action of osteoblasts (bone formation) and osteoclasts (bone resorption). Together these local adaptive remodeling activities sum up to strengthen bone glob...
Source: Annals of Biomedical Engineering - May 22, 2012 Category: Biomedical Engineering Authors: Trüssel A, Müller R, Webster D Tags: Ann Biomed Eng Source Type: research

An investigation into the use and limitations of different spatial integration schemes and finite element software in head impact analyses.
Abstract To understand the mechanopathogenesis of brain lesions, finite element (FE) head models are used. There is a broad range of material properties, contact interfaces and integration schemes used for the different parts in current FE head models. The effect of material behaviour and contact definitions on a head impact analysis is reported in the literature, whereas the effect of FE integration schemes is a rather unexplored domain. This paper starts with the development of a simplified head model to which small adaptations are made in the integration scheme to obtain multiple analyses that are compared using...
Source: Computer Methods in Biomechanics and Biomedical Engineering - May 22, 2012 Category: Biomedical Engineering Authors: Baeck K, Goffin J, Vander Sloten J Tags: Comput Methods Biomech Biomed Engin Source Type: research

Biomechanical behaviour of ankle ligaments: constitutive formulation and numerical modelling.
This study was aimed at the definition of a constitutive formulation of ankle ligaments and of a procedure for the constitutive parameters evaluation, for the biomechanical analysis by means of numerical models. To interpret the typical features of ligaments mechanical response, as anisotropic configuration, geometric non-linearity, non-linear elasticity and time-dependent behaviour, a specific fibre-reinforced visco-hyperelastic model is provided. The identification of constitutive parameters is performed by a stochastic-deterministic procedure that minimises the discrepancy between experimental and computational results....
Source: Computer Methods in Biomechanics and Biomedical Engineering - May 22, 2012 Category: Biomedical Engineering Authors: Forestiero A, Carniel EL, Natali AN Tags: Comput Methods Biomech Biomed Engin Source Type: research

Zeroing of six-component handrim dynamometer for biomechanical studies of manual wheelchair locomotion.
Abstract A six-component handrim dynamometer (HRD) is a dynamometer that rotates around the wheel axle during measurements. For this kind of dynamometer, static zero level calibration is insufficient because the proportion of the forces (i.e. handrim weight and centrifugal force) measured by each sensor varies according to the angular position and velocity of the dynamometer. The dynamic calibration presented in this paper is based on the direct correction of the sensor signals using Fourier's polynomials that take into account the influences of both the handrim weight distribution on the sensors with respect to th...
Source: Computer Methods in Biomechanics and Biomedical Engineering - May 22, 2012 Category: Biomedical Engineering Authors: Sauret C, Dabonneville M, Couétard Y, de Saint Rémy N, Kauffmann P, Cid M, Vaslin P Tags: Comput Methods Biomech Biomed Engin Source Type: research

Homotopy semi-numerical simulation of peristaltic flow of generalised Oldroyd-B fluids with slip effects.
Abstract This investigation deals with the peristaltic flow of generalised Oldroyd-B fluids (with the fractional model) through a cylindrical tube under the influence of wall slip conditions. The analysis is carried out under the assumptions of long wavelength and low Reynolds number. Analytical approximate solutions are obtained by using the highly versatile and rigorous semi-numerical procedure known as the homotopy analysis method. It is assumed that the cross section of the tube varies sinusoidally along the length of the tube. The effects of the dominant hydromechanical parameters, i.e. fractional parameters, ...
Source: Computer Methods in Biomechanics and Biomedical Engineering - May 22, 2012 Category: Biomedical Engineering Authors: Tripathi D, Bég OA, Curiel-Sosa JL Tags: Comput Methods Biomech Biomed Engin Source Type: research

Importance of diameter-to-length ratio in selecting dental implants: a methodological finite element study.
Abstract Implant dimensions greatly influence load transfer characteristics and the lifetime of a dental system. Excessive stresses at peri-implant area may result in bone failure. Finding the critical point at the implant-bone interface and evaluating the influence of implant diameter-to-length ratio on adjacent bone stresses makes it possible to select implant dimensions. For this, different cylindrical implants were numerically analysed using geometrical models generated from computed tomography images of mandible with osseointegrated implants. All materials were assumed to be linearly elastic and isotropic. Mas...
Source: Computer Methods in Biomechanics and Biomedical Engineering - May 22, 2012 Category: Biomedical Engineering Authors: Demenko V, Linetskiy I, Nesvit K, Hubalkova H, Nesvit V, Shevchenko A Tags: Comput Methods Biomech Biomed Engin Source Type: research

Quantitative modeling of transcriptional regulatory networks by integrating multiple source of knowledge.
Abstract A key challenge in the post genome era is to identify genome-wide transcriptional regulatory networks, which specify the interactions between transcription factors and their target genes. In this work, a regulatory model-based binding energy is proposed to quantify the transcriptional regulatory network. Multiple quantities, including binding affinity, regulatory efficiency, and the activity level of transcription factor (TF) are incorporated into a general learning model. The sequence features of the promoter are exploited to derive the binding energy. Comparing with the previous models that only employ m...
Source: Bioprocess and Biosystems Engineering - May 22, 2012 Category: Biomedical Engineering Authors: Wang SQ, Li HX Tags: Bioprocess Biosyst Eng Source Type: research

Reaction rate reconstruction from biomass concentration measurement in bioreactors using modified second-order sliding mode algorithms.
Abstract This paper deals with the estimation of unknown signals in bioreactors using sliding observers. Particular attention is drawn to estimate the specific growth rate of microorganisms from measurement of biomass concentration. In a recent article, notions of high-order sliding modes have been used to derive a growth rate observer for batch processes. In this paper we generalize and refine these preliminary results. We develop a new observer with a different error structure to cope with other types of processes. Furthermore, we show that these observers are equivalent, under coordinate transformations and time...
Source: Bioprocess and Biosystems Engineering - May 22, 2012 Category: Biomedical Engineering Authors: De Battista H, Picó J, Garelli F, Navarro JL Tags: Bioprocess Biosyst Eng Source Type: research

Biocompatibility assessment of Si-based nano- and micro-particles.
Abstract Silicon is one of the most abundant chemical elements found on the Earth. Due to its unique chemical and physical properties, silicon based materials and their oxides (e.g. silica) have been used in several industries such as building and construction, electronics, food industry, consumer products and biomedical engineering/medicine. This review summarizes studies on effects of silicon and silica nano- and micro-particles on cells and organs following four main exposure routes, namely, intravenous, pulmonary, dermal and oral. Further, possible genotoxic effects of silica based nanoparticles are discussed. ...
Source: Advanced Drug Delivery Reviews - May 22, 2012 Category: Drugs & Pharmacology Authors: Jaganathan H, Godin B Tags: Adv Drug Deliv Rev Source Type: research

A coupled flow-acoustic computational study of bruits from a modeled stenosed artery
Abstract The sound generated by blood flow in stenosed arteries is investigated for a model that consists of a channel with a one-sided constriction. The blood flow-induced arterial “bruits” are computed directly using a hybrid approach wherein the hemodynamic flow field is solved by an immersed boundary, incompressible flow solver, and the sound generation is modeled by a first-principles approach that employs the linearized compressible perturbation equations. The transmission and propagation of the sound through the surrounding biological tissues is also modeled with a simplified, linear structural wa...
Source: Medical and Biological Engineering and Computing - May 21, 2012 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: research

Development and application of a portable manual non-contact-type goniometric instrument for measuring human anatomical angular parameters
Abstract: Several manual contact-type goniometric instruments have previously been developed to measure joint range of motion (ROM) during physical-therapy evaluation. These include the universal goniometer and the gravity-dependent goniometer, or inclinometer, which are used to measure the ROM angle of a subject in a fully erect posture. Here, we developed a manual non-contact-type portable goniometric instrument for the measurement of anatomical angular parameters based on the principle of spot irradiation by using laser markers. The accuracy of the developed instrument was tested and its performance was compared with th...
Source: Medical Engineering and Physics - May 21, 2012 Category: Biomedical Engineering Authors: Shin-ichi Susato Tags: Papers Source Type: research

Investigations concerning the application of the cross-correlation method in cardiac output measurements
Conclusions: The performed investigations and theoretical analysis have shown, that the cross-correlation method may be applied in cardiac output measurements. This kind of measurements seems to be more accurate and disturbance-resistant than clinically applied thermodilution.
Source: BioMedical Engineering OnLine - May 20, 2012 Category: Biomedical Engineering Authors: Maciej GawlikowskiTadeusz Pustelny Source Type: research

Optimal compressed sensing reconstructions of fMRI using deterministic and stochastic sampling geometries
Conclusions: We have found that compressive sensing parameter optimization can dramatically improve fMRI image reconstruction quality. Furthermore, 2D MRI scanning based on the SLP geometries consistently gave the best image reconstruction results. The implication of this result is that less complex sampling geometries will suffice over random sampling. We have also found that we can obtain stable parameter regions that can be used to achieve specific levels of image reconstruction quality when combined with specific k-space sampling geometries. Furthermore, median parameter values can be used to obtain excellent reconstru...
Source: BioMedical Engineering OnLine - May 20, 2012 Category: Biomedical Engineering Authors: Oliver JerominMarios PattichisVince Calhoun Source Type: research

Development of Automated Image Stitching System for Radiographic Images
Abstract Standard X-ray images using conventional screen-film technique have a limited field of view that is insufficient to show the full bone structure of large hands on a single frame. To produce images containing the whole hand structure, digitized images from the X-ray films can be assembled using image stitching. This paper presents a new medical image stitching method that utilizes minimum average correlation energy filters to identify and merge pairs of hand X-ray medical images. The effectiveness of the proposed method is demonstrated in the experiments involving two databases which contain a total ...
Source: Journal of Digital Imaging - May 19, 2012 Category: Radiology Tags: Journal of Digital Imaging Source Type: research

Salubrinal promotes healing of surgical wounds in rat femurs
Abstract Phosphorylation of eukaryotic initiation factor 2α (eIF2α), transiently activated by various cellular stresses, is known to alleviate stress-induced cellular damage. Here, we addressed a question: does elevation of eIF2α phosphorylation by salubrinal (a pharmacological inhibitor of eIF2α dephosphorylation) enhance healing of bone wounds? We hypothesized that salubrinal would accelerate a closure of surgically generated bone holes by modifying expression of stress-sensitive genes. To examine this hypothesis, we employed a rat wound model. Surgical wounds were generated on anterior and posterior f...
Source: Journal of Bone and Mineral Metabolism - May 19, 2012 Category: Orthopaedics Tags: Journal of Bone and Mineral Metabolism Source Type: research

High-resolution esophageal long-term ECG allows detailed atrial wave morphology analysis in case of atrial ectopic beats
Abstract Detection of arrhythmic atrial beats in surface ECGs can be challenging when they are masked by the R or T wave, or do not affect the RR-interval. Here, we present a solution using a high-resolution esophageal long-term ECG that offers a detailed view on the atrial electrical activity. The recorded ECG shows atrial ectopic beats with long coupling intervals, which can only be successfully classified using additional morphology criteria. Esophageal high-resolution ECGs provide this information, whereas surface long-term ECGs show poor atrial signal quality. This new method is a promising tool for the...
Source: Medical and Biological Engineering and Computing - May 19, 2012 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: research

Application of adaptive DO-stat feeding control to Pichia pastoris X33 cultures expressing a single chain antibody fragment (scFv).
In this study, fed-batch cultures of a Pichia pastoris strain constitutively expressing a single chain antibody fragment (scFv) under the control of the glyceraldehyde-3-phosphate dehydrogenase (GAP) promoter were performed in a pilot 50 L bioreactor. Due to the very high cell density achieved within the first 75 h, typically between 140 and 160 g-DCW/L of dry cell weight (DCW), most of the scFv is produced under hard oxygen transfer limitation. To improve scFv productivity, a direct adaptive dissolved oxygen (DO)-stat feeding controller that maximizes glycerol feeding under the constraint of available oxygen transfer ca...
Source: Bioprocess and Biosystems Engineering - May 19, 2012 Category: Biomedical Engineering Authors: Ferreira AR, Ataíde F, von Stosch M, Dias JM, Clemente JJ, Cunha AE, Oliveira R Tags: Bioprocess Biosyst Eng Source Type: research

IEEE Transactions on Biomedical Engineering Associate Editors
Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research

IEEE Transactions on Biomedical Engineering information for authors
Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research

Evaluation of a Smartphone Platform as a Wireless Interface Between Tongue Drive System and Electric-Powered Wheelchairs
Tongue drive system (TDS) is a new wireless assistive technology (AT) for the mobility impaired population. It provides users with the ability to drive powered wheelchairs (PWC) and access computers using their unconstrained tongue motion. Migration of the TDS processing unit and user interface platform from a bulky personal computer to a smartphone (iPhone) has significantly facilitated its usage by turning it into a true wireless and wearable AT. After implementation of the necessary interfacing hardware and software to allow the smartphone to act as a bridge between the TDS and PWC, the wheelchair navigation performance...
Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research

Methods for Automated Identification of Informative Behaviors in Natural Bioptic Driving
Visually impaired people may legally drive if wearing bioptic telescopes in some developed countries. To address the controversial safety issue of the practice, we have developed a low-cost in-car recording system that can be installed in study participants’ own vehicles to record their daily driving activities. We also developed a set of automated identification techniques of informative behaviors to facilitate efficient manual review of important segments submerged in the vast amount of uncontrolled data. Here, we present the methods and quantitative results of the detection performance for six types of driving ma...
Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research

Redundancy Resolution of the Human Arm and an Upper Limb Exoskeleton
The human arm has 7 degrees of freedom (DOF) while only 6 DOF are required to position the wrist and orient the palm. Thus, the inverse kinematics of an human arm has a nonunique solution. Resolving this redundancy becomes critical as the human interacts with a wearable robot and the inverse kinematics solution of these two coupled systems must be identical to guarantee an seamless integration. The redundancy of the arm can be formulated by defining the swivel angle, the rotation angle of the plane defined by the upper and lower arm around a virtual axis that connects the shoulder and wrist joints. Analyzing reaching tasks...
Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research

A Simulation Study of the Combined Thermoelectric Extracellular Stimulation of the Sciatic Nerve of the Xenopus Laevis: The Localized Transient Heat Block
The electrical behavior of the Xenopus laevis nerve fibers was studied when combined electrical (cuff electrodes) and optical (infrared laser, low power sub-5 mW) stimulations are applied. Assuming that the main effect of the laser irradiation on the nerve tissue is the localized temperature increase, this paper analyzes and gives new insights into the function of the combined thermoelectric stimulation on both excitation and blocking of the nerve action potentials (AP). The calculations involve a finite-element model (COMSOL) to represent the electrical properties of the nerve and cuff. Electric-field distribution ...
Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research

A Subject-Independent Method for Automatically Grading Electromyographic Features During a Fatiguing Contraction
We present here a subject-independent framework for monitoring the changes in EMG features that accompany muscle fatigue based on principal component analysis and factor analysis. The proposed framework is based on several time- and frequency-domain features, unlike most of the existing work, which is based on two to three features. Results show that latent factors obtained from factor analysis on these features provide a robust and unified framework. This framework learns a model from EMG signals of multiple subjects, that form a reference group, and monitors the changes in EMG features during a sustained submaximal contr...
Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research

A Comparative Study of Graph-Based, Eikonal, and Monodomain Simulations for the Estimation of Cardiac Activation Times
In this study, we present a graph-based method, which relies on point-to-point path finding to estimate activation times for single points in cardiac tissue with minimal computational costs. To validate our approach, activation times are compared to monodomain simulation results for an anatomically based rabbit ventricular model, incorporating realistic fiber orientation and conduction heterogeneities. Differences in activation times between the graph-based method and monodomain results are less than 10$%$ of the total activation time, and computational performance is orders of magnitude faster with the proposed method whe...
Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research

Viscoelastic Modeling of the Contact Interaction Between a Tactile Sensor and an Atrial Tissue
Modeling and parameter identification of soft tissue are essential in establishing an accurate contact model for tool–tissue interaction, which can be used in the development of high-fidelity surgical instruments. This paper discusses the interaction between a tissue and a tactile sensor in minimally invasive surgery, the focus being a novel technique for robotic-assisted mitral valve repair, in which tactile sensors are used to distinguish between different kinds of tissue by their relative softness. A discrete viscoelastic model is selected to represent the tissue behavior. To populate the model of the tissue with...
Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research

An Ensemble-Based System for Microaneurysm Detection and Diabetic Retinopathy Grading
Reliable microaneurysm detection in digital fundus images is still an open issue in medical image processing. We propose an ensemble-based framework to improve microaneurysm detection. Unlike the well-known approach of considering the output of multiple classifiers, we propose a combination of internal components of microaneurysm detectors, namely preprocessing methods and candidate extractors. We have evaluated our approach for microaneurysm detection in an online competition, where this algorithm is currently ranked as first, and also on two other databases. Since microaneurysm detection is decisive in diabetic retinopat...
Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research

Image Reconstruction for Hybrid True-Color Micro-CT
X-ray micro-CT is an important imaging tool for biomedical researchers. Our group has recently proposed a hybrid “true-color” micro-CT system to improve contrast resolution with lower system cost and radiation dose. The system incorporates an energy-resolved photon-counting true-color detector into a conventional micro-CT configuration, and can be used for material decomposition. In this paper, we demonstrate an interior color-CT image reconstruction algorithm developed for this hybrid true-color micro-CT system. A compressive sensing-based statistical interior tomography method is employed to reconstruct eac...
Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research

Generating Stochastic Gene Regulatory Networks Consistent With Pathway Information and Steady-State Behavior
We present a procedure to generate a stochastic genetic regulatory network model consistent with pathway information. Using the stochastic dynamics of Markov chains, we produce a model constrained by the prior knowledge despite the sometimes incomplete, time independent, and often conflicting nature of these pathways. We apply the Markov theory to study the model’s long run behavior and introduce a biologically important transformation to aid in comparison with real biological outcome prediction in the steady-state domain. Our technique produces biologically faithful models without the need for rate kinetics, detail...
Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research

Real-Time Automatic Tuning of Noise Suppression Algorithms for Cochlear Implant Applications
The performance of cochlear implants deteriorates in noisy environments compared to quiet conditions. This paper presents an adaptive cochlear implant system, which is capable of classifying the background noise environment in real time for the purpose of adjusting or tuning its noise suppression algorithm to that environment. The tuning is done automatically with no user intervention. Five objective quality measures are used to show the superiority of this adaptive system compared to a conventional fixed noise-suppression system. Steps taken to achieve the real-time implementation of the entire system, incorporating both ...
Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research

Multilevel Segmentation of Histopathological Images Using Cooccurrence of Tissue Objects
This paper presents a new approach for unsupervised segmentation of histopathological tissue images. This approach has two main contributions. First, it introduces a new set of high-level texture features to represent the prior knowledge of spatial organization of the tissue components. These texture features are defined on the tissue components, which are approximately represented by tissue objects, and quantify the frequency of two component types being cooccurred in a particular spatial relationship. As they are defined on components, rather than on image pixels, these object cooccurrence features are expected to be les...
Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research

Surface Mosaics of the Bladder Reconstructed From Endoscopic Video for Automated Surveillance
Flexible cystoscopy is frequently performed for recurrent bladder cancer surveillance, making it the most expensive cancer to treat over the patient's lifetime. An automated bladder surveillance system is being developed to robotically scan the bladder surface using an ultrathin and highly flexible endoscope. Such a system would allow cystoscopic procedures to be overseen by technical staff while urologists could review cystoscopic video postoperatively. In this paper, we demonstrate a method for reconstructing the surface of the whole bladder from endoscopic video using structure from motion. Video is acquired from...
Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research

Enhancing the Accuracy of Subcutaneous Glucose Sensors: A Real-Time Deconvolution-Based Approach
In this study, we design and test a real-time signal-enhancement module that, cascaded to the CGM device, improves the quality of its output by a proper postprocessing of the CGM signal. In fact, CGM sensors measure glucose in the interstitium rather than in the blood compartment. We show that this distortion can be compensated by means of a regularized deconvolution procedure relying on a linear regression model that can be updated whenever a pair of suitably sampled SMBG references is collected. Tests performed both on simulated and real data demonstrate a significant accuracy improvement of the CGM signal. Simulation st...
Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research

High-Density Myoelectric Pattern Recognition Toward Improved Stroke Rehabilitation
Myoelectric pattern-recognition techniques have been developed to infer user's intention of performing different functional movements. Thus electromyogram (EMG) can be used as control signals of assisted devices for people with disabilities. Pattern-recognition-based myoelectric control systems have rarely been designed for stroke survivors. Aiming at developing such a system for improved stroke rehabilitation, this study assessed detection of the affected limb's movement intention using high-density surface EMG recording and pattern-recognition techniques. Surface EMG signals comprised of 89 channels were re...
Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research

Time-Based Compression and Classification of Heartbeats
Heart function measured by electrocardiograms (ECG) is crucial for patient care. ECG generated waveforms are used to find patterns of irregularities in cardiac cycles in patients. In many cases, irregularities evolve over an extended period of time that requires continuous monitoring. However, this requires wireless ECG recording devices. These devices consist of an enclosed system that includes electrodes, processing circuitry, and a wireless communication block imposing constraints on area, power, bandwidth, and resolution. In order to provide continuous monitoring of cardiac functions for real-time diagnostics, we propo...
Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research

Nonstationary Harmonic Modeling for ECG Removal in Surface EMG Signals
We present a compact approach for mitigating the presence of electrocardiograms (ECG) in surface electromyographic (EMG) signals by means of time-variant harmonic modeling of the cardiac artifact. Heart rate and QRS complex variability, which often account for amplitude and frequency time variations of the ECG, are simultaneously captured by a set of third-order constant-coefficient polynomials modulating a stationary harmonic basis in the analysis window. Such a characterization allows us to significantly suppress ECG from the mixture by preserving most of the EMG signal content at low frequencies (less than 20 Hz)...
Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research

Automatic Detection and Quantification of Tree-in-Bud (TIB) Opacities From CT Scans
This study presents a novel computer-assisted detection (CAD) system for automatically detecting and precisely quantifying abnormal nodular branching opacities in chest computed tomography (CT), termed tree-in-bud (TIB) opacities by radiology literature. The developed CAD system in this study is based on 1) fast localization of candidate imaging patterns using local scale information of the images, and 2) Möbius invariant feature extraction method based on learned local shape and texture properties of TIB patterns. For fast localization of candidate imaging patterns, we use ball-scale filtering and, based on the obs...
Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research

Classification of Periodic Activities Using the Wasserstein Distance
In this paper, we introduce a novel nonparametric classification technique based on the use of the Wasserstein distance. The proposed scheme is applied in a biomedical context for the analysis of recorded accelerometer data: the aim is to retrieve three types of periodic activities (walking, biking, and running) from a time–frequency representation of the data. The main interest of the use of the Wasserstein distance lies in the fact that it is less sensitive to the location of the frequency peaks than to the global structure of the frequency pattern, allowing us to detect activities almost independently of their sp...
Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research

Filter-Based Methodology for the Location of Hot Spots in Proteins and Exons in DNA
The so-called receiver operating characteristic technique is used as a tool in an optimization procedure for the improvement and assessment of a filter-based methodology for the location of hot spots in protein sequences and exons in DNA sequences. By optimizing the characteristic values of the nucleotides, high efficiency as well as improved accuracy can be achieved relative to results obtained with the electron–ion interaction potentials. On the other hand, by using the proposed filter-based methodology with binary sequences, improved accuracy can be achieved although the efficiency is somewhat compromised relativ...
Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research

A Multiscale Model for Bioimpedance Dispersion of Liver Tissue
This study demonstrates the potential of a multiscale model in determining the stoppage of blood flow during surgery.
Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research

Modeling the Field Distribution in Deep Brain Stimulation: The Influence of Anisotropy of Brain Tissue
The neurosurgical method of deep brain stimulation (DBS) is used to treat symptoms of movement disorders like Parkinson’s disease by implanting stimulation electrodes in deep brain areas. The aim of this study was to examine the field distribution in DBS and the role of heterogeneous and anisotropic material properties in the brain areas where stimulation is applied. Finite element models of the human brain were developed comprising tissue heterogeneity and anisotropy. The tissue data were derived from averaged magnetic resonance imaging and diffusion tensor imaging datasets. Unilateral stimulation of the subthalami...
Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research

Extrapolatable Analytical Functions for Tendon Excursions and Moment Arms From Sparse Datasets
We present a novel method that simultaneously estimates both the form and parameter values of arbitrary analytical expressions for tendon excursions and moment arms over the entire range of motion from sparse datasets. This symbolic regression method based on genetic programming has been shown to find the appropriate form of mathematical expressions that capture the physics of mechanical systems. We demonstrate this method by applying it to 1) experimental data from a physical tendon-driven robotic system with arbitrarily routed multiarticular tendons and 2) synthetic data from musculoskeletal models. We show it outperform...
Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research

A State-Space Modeling Approach for Localization of Focal Current Sources From MEG
In this study, we propose a novel state-space model-based method that resolves these problems, extending our previous source localization method to include a temporal constraint by state-space modeling. To enable focal current reconstruction, we account for spatially inhomogeneous temporal dynamics by introducing dynamics model parameters that differ for each cortical position. The model parameters and the intensity of the current sources are jointly estimated according to a Bayesian framework. We circumvent the high dimensionality of the problem by assuming prior distributions of the model parameters to reduce the sensiti...
Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research

Neural Network Incorporating Meal Information Improves Accuracy of Short-Time Prediction of Glucose Concentration
Diabetes mellitus is one of the most common chronic diseases, and a clinically important task in its management is the prevention of hypo/hyperglycemic events. This can be achieved by exploiting continuous glucose monitoring (CGM) devices and suitable short-term prediction algorithms able to infer future glycemia in real time. In the literature, several methods for short-time glucose prediction have been proposed, most of which do not exploit information on meals, and use past CGM readings only. In this paper, we propose an algorithm for short-time glucose prediction using past CGM sensor readings and information on carboh...
Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research

Embedding Topic Discovery in Conditional Random Fields Model for Segmenting Nuclei Using Multispectral Data
Segmentation of cells/nuclei is a challenging problem in 2-D histological and cytological images. Although a large number of algorithms have been proposed, newer efforts continue to be devoted to investigate robust models that could have high level of adaptability with regard to considerable amount of image variability. In this paper, we propose a multiclassification conditional random fields (CRFs) model using a combination of low-level cues (bottom–up) and high-level contextual information (top–down) for separating nuclei from the background. In our approach, the contextual information is extracted by an un...
Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research

Phantom Model of Physiologic Intracranial Pressure and Cerebrospinal Fluid Dynamics
We describe herein a novel life-size phantom model of the intracranial cavity and its validation. The cerebrospinal fluid (CSF) domains including ventricular, cysternal, and subarachnoid spaces were derived via magnetic resonance imaging. Brain mechanical properties and cranio-spinal compliance were set based on published data. Both bulk and pulsatile physiologic CSF flow were modeled. Model validation was carried out by comparisons of flow and pressure measurements in the phantom with published in vivo data of healthy subjects. Physiologic intracranial pressure with 10 mmHg mean and 0.4 mmHg peak pulse amplitude was recor...
Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research

Depth Discontinuity-Based Cup Segmentation From Multiview Color Retinal Images
Accurate segmentation of the cup region from retinal images is needed to derive relevant measurements for glaucoma assessment. A novel, depth discontinuity (in the retinal surface)-based approach to estimate the cup boundary is proposed in this paper. The proposed approach shifts focus from the cup region used by existing approaches to cup boundary. The given set of images, acquired sequentially, are related via a relative motion model and the depth discontinuity at the cup boundary is determined from cues such as motion boundary and partial occlusion. The information encoded by these cues is used to approximate the cup bo...
Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research

Electrodiffusion of Molecules in Aqueous Media: A Robust, Discretized Description for Electroporation and Other Transport Phenomena
Electrically driven transport of molecules and ions within aqueous electrolytes is of long-standing interest, with direct relevance to applications that include the delivery/release of biologically active solutes to/from cells and tissues. Examples include iontophoretic and electroporation-mediated drug delivery. Here, we describe a robust method for characterizing electrodiffusive transport in physiologic aqueous media. Specifically, we treat the case of solute present in sufficiently low concentration as to negligibly contribute to the total ionic current within the system. In this limiting case, which applies to many sy...
Source: IEEE Transactions on Biomedical Engineering - May 18, 2012 Category: Biomedical Engineering Source Type: research