MedWorm.com provides a medical RSS filtering service. Over 6000 RSS medical sources are combined and output via different filters. This feed contains the latest items from the 'IEEE Transactions on Biomedical Engineering' source. Tue, 07 Feb 2012 07:42:48 +0100 http://www.medworm.com/index.php?rid=5657883&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6132598%26arnumber%3D6135532 (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5657883 Wed, 01 Feb 2012 05:00:00 +0100 5657883 http://www.medworm.com/index.php?rid=5645074&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6132598%26arnumber%3D6072256 Although the spontaneous brain rhythms of sleep have commanded much recent interest, their detection and analysis remains suboptimal. In this paper, we develop a data-driven Bayesian algorithm for sleep spindle detection on the electroencephalography (EEG). The algorithm exploits the Karhunen–Loève transform and Bayesian hypothesis testing to produce the instantaneous probability of a spindle’s presence with maximal resolution. In addition to possessing flexibility, transparency, and scalability, this algorithm could perform at levels superior to standard methods for EEG event detection. (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5645074 Wed, 01 Feb 2012 05:00:00 +0100 5645074 http://www.medworm.com/index.php?rid=5626157&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6132598%26arnumber%3D6132602 (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5626157 Wed, 25 Jan 2012 14:46:10 +0100 5626157 http://www.medworm.com/index.php?rid=5626156&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6132598%26arnumber%3D6132603 (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5626156 Wed, 25 Jan 2012 14:46:10 +0100 5626156 http://www.medworm.com/index.php?rid=5626155&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6132598%26arnumber%3D6132604 (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5626155 Wed, 25 Jan 2012 14:46:10 +0100 5626155 http://www.medworm.com/index.php?rid=5626154&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6132598%26arnumber%3D6095607 Human hand movements have been studied for many decades, yet the role of hand biomechanics in achieving dexterity has not been fully understood. In this paper, we investigate the contributions of the intrinsic passive viscoelastic component in the hand during the coordinated wrist and hand movements. We compare the contributions of stiffness, damping, and dynamics torques under two types of joint phase movements at two speeds. The analysis of the data collected from subject studies demonstrated that the passive visco-elastic component is dominant over dynamic coupling terms. Although the exact contributions of the three torques vary under different speeds and phasic movements, the stiffness torque was the highest (at least 47%) followed by the damping torque, while the dynamics torq... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5626154 Wed, 25 Jan 2012 14:46:10 +0100 5626154 http://www.medworm.com/index.php?rid=5626153&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6132598%26arnumber%3D6095334 Patients are not able to call for help during a generalized tonic–clonic epileptic seizure. Our objective was to develop a robust generic algorithm for automatic detection of tonic–clonic seizures, based on surface electromyography (sEMG) signals suitable for a portable device. Twenty-two seizures were analyzed from 11 consecutive patients. Our method is based on a high-pass filtering with a cutoff at 150 Hz, and monitoring a count of zero crossings with a hysteresis of $pm 50,mu hbox{V}$ . Based on data from one sEMG electrode (on the deltoid muscle), we achieved a sensitivity of 100% with a mean detection latency of 13.7  s, while the rate of false detection was limited to 1 false alarm per 24 h. The overall performance of the presented generic algorith... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5626153 Wed, 25 Jan 2012 14:46:10 +0100 5626153 http://www.medworm.com/index.php?rid=5626152&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6132598%26arnumber%3D6087276 In an effort to open up new opportunities in individualized anesthesia care, this paper presents a dynamic dose-response model of propofol that relates propofol dose (i.e., infusion rate) directly to a clinical effect. The proposed model consists of a first-order equilibration dynamics plus a nonlinear Hill equation model, each representing the transient distribution of propofol dose from the plasma to the effect site and the steady-state dose-effect relationship. Compared to traditional pharmacokinetic-pharmacodynamic (PKPD) models, the proposed model has structural parsimony and comparable predictive capability, making it more attractive than its PKPD counterpart for identifying an individualized dose-response model in real-time. The efficacy of the direct dynamic dose-response model ove... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5626152 Wed, 25 Jan 2012 14:46:10 +0100 5626152 http://www.medworm.com/index.php?rid=5626151&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6132598%26arnumber%3D6086594 We present a method to monitor a patient and the equipment in a radiotherapy treatment room, by exploiting the information in the treatment plan, enriched with other elements such as visual, geometric, and “semantic” information. Using all these information items, and a generic model, a virtual environment of the scene is created, with maximum precision. The images resulting from video sequences with several cameras are also used to confront the filmed information on the scene and its numerical representation. The method is based on the features of the scene elements, and on a fuzzy formalism. The feasibility of the method is being quantitatively evaluated in the absence of treatment, to be further exploited in a module for external control by video in real conditions. (Sourc... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5626151 Wed, 25 Jan 2012 14:46:10 +0100 5626151 http://www.medworm.com/index.php?rid=5626150&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6132598%26arnumber%3D6084729 It is difficult to build an accurate and smooth liver vessel model due to the tiny size, noise, and n-furcations of vessels. To overcome these problems, we propose an n-furcation vessel tree modeling method. In this method, given a segmented volume and a point indicating the root of the vessels, centerlines and cross-sectional contours of the vessels are extracted and organized as a tree first. Then, the tree is broken up into separate branches in descending order of length, and polygonal meshes of all the branches are separately constructed from the cross-sectional contours. Finally, all the meshes are combined sequentially using our hole-making approach. Holes are made on a coarse mesh, and a final fine mesh is generated using a subdivision method. The hole-making approach with the subdi... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5626150 Wed, 25 Jan 2012 14:46:10 +0100 5626150 http://www.medworm.com/index.php?rid=5626149&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6132598%26arnumber%3D6075242 Recent developments in flexible endoscopy and other fields of medical technology have raised the need for compact slender shafts that can be made rigid and compliant at will. A novel compact mechanism, named FORGUIDE, with this functionality was developed. The FORGUIDE shaft rigidifies due to friction between a ring of cables situated between a spring and an inflated tube. A mathematical model for the FORGUIDE mechanism working principle was made and used to obtain understanding of this mechanism, predict the maximum rigidity of a FORGUIDE shaft design, and tune its design variables. The mathematical model gave suggestions for significant performance improvement by fine-tuning the design. A prototype FORGUIDE shaft was built and put to a series of bench tests. These tests showed that the F... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5626149 Wed, 25 Jan 2012 14:46:10 +0100 5626149 http://www.medworm.com/index.php?rid=5626148&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6132598%26arnumber%3D6074931 Typical mosaicing schemes assume that to-be-combined images are equally informative; thus, the images are processed in a similar manner. However, the new imaging technique for confocal fluorescence images has revealed a problem when two asymmetrically informative biological images are stitched during microscope image mosaicing. The latter process is widely used in biological studies to generate a higher resolution image by combining multiple images taken at different times and angles. To resolve the earlier problem, we propose a multiresolution optimization approach that evaluates the blending coefficients based on the relative importance of the overlapping regions of the to-be-combined image pair. The blending coefficients are the optimal solution obtained by a quadratic programming algor... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5626148 Wed, 25 Jan 2012 14:46:10 +0100 5626148 http://www.medworm.com/index.php?rid=5626147&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6132598%26arnumber%3D6074932 Compact tactile matrix (CTM) is a vibrotactile device composed of a seven-by-seven array of electromechanical vibrators “tactip” used to represent tactile patterns applied to a small skin area. The CTM uses a dynamic feature to generate spatiotemporal tactile patterns. The design requirements focus particularly on maximizing the transmission of the vibration from one tactip to the others as well as to the skin over a square area of 16 cm$^2$ while simultaneously minimizing the transmission of vibrations throughout the overall structure of the CTM. Experiments were conducted on 22 unpracticed subjects to evaluate how the CTM could be used to develop a tactile semantics for communication of instructions in order to test the ability of the subjects to identify: 1) directional pr... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5626147 Wed, 25 Jan 2012 14:46:09 +0100 5626147 http://www.medworm.com/index.php?rid=5626146&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6132598%26arnumber%3D6074930 Spreading depression (SD) consists of a transient significant suppression of the spontaneous neural electrical activity that spreads slowly across regions of the gray matter in a wave form. Nowadays, this phenomenon is being studied by means of mathematical and computational models to reproduce the main characteristics of SD. Given the high number of parameters and their unknown ranges of variation, the setting of parameters for current SD models is usually a hard task that must be addressed in order to make such models reproduce real data. In this paper, we present a 1-D model which is able to reproduce the most important characteristics of SD waves observed in laboratory experiments: the slow extracellular potential shift and extracellular ionic concentration variations regarding speed, ... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5626146 Wed, 25 Jan 2012 14:46:09 +0100 5626146 http://www.medworm.com/index.php?rid=5626145&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6132598%26arnumber%3D6072255 A cross-validation (CV) method based on state-space framework is introduced for comparing the fidelity of different cortical interaction models to the measured scalp electroencephalogram (EEG) or magnetoencephalography (MEG) data being modeled. A state equation models the cortical interaction dynamics and an observation equation represents the scalp measurement of cortical activity and noise. The measured data are partitioned into training and test sets. The training set is used to estimate model parameters and the model quality is evaluated by computing test data innovations for the estimated model. Two CV metrics normalized mean square error and log-likelihood are estimated by averaging over different training/test partitions of the data. The effectiveness of this method of model selecti... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5626145 Wed, 25 Jan 2012 14:46:09 +0100 5626145 http://www.medworm.com/index.php?rid=5626144&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6132598%26arnumber%3D6072257 This paper reports on a novel system architecture for measuring impedance spectra of a biological tissue close to the tip of a hollow needle. The measurement is performed online using fast broadband chirp signals. The time domain measurement raw data are transformed into the transfer function of the tissue in frequency domain. Correlation technique is used to analyze the characteristic shape of the derived tissue transfer function with respect to known “library functions” for different types of tissue derived in earlier experiments. Based on the resulting correlation coefficients the exact type of tissue is determined. A bipolar coaxial needle is constructed, simulated by finite element method and tested during various in vitro and in vivo experiments. The results show a good... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5626144 Wed, 25 Jan 2012 14:46:09 +0100 5626144 http://www.medworm.com/index.php?rid=5626143&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6132598%26arnumber%3D6070974 We propose a novel approach aimed at adaptively setting the threshold of the smoothed Teager energy operator (STEO) detector to be used in extracellular recording of neural signals. In this proposed approach, to set the adaptive threshold of the STEO detector, we derive the relationship between the low-order statistics of its input signal and the ones of its output signal. This relationship is determined with only the background noise component assumed to be present at the input. Robust statistics theory techniques were used to achieve an unbiased estimation of these low-order statistics of the background noise component directly from the neural input signal. In this paper, the emphasis is made on extracellular neural recordings. However, the proposed method can be used in the analysis of ... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5626143 Wed, 25 Jan 2012 14:46:09 +0100 5626143 http://www.medworm.com/index.php?rid=5626142&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6132598%26arnumber%3D6069850 In this paper, we propose an active contour model using local morphology fitting for automatic vascular segmentation on 2-D angiogram. The vessel and background are fitted to fuzzy morphology maximum and minimum opening, separately, using linear structuring element with adaptive scale and orientation. The minimization of the energy associated with the active contour model is implemented within a level set framework. As in the current local model, fitting the image to local region information makes the model robust against the inhomogeneous background. Moreover, selective local estimations for fitting that are precomputed instead of updated in each contour evolution makes the evolution of level set robust again initial location compared to the current local model. The results on synthetic i... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5626142 Wed, 25 Jan 2012 14:46:09 +0100 5626142 http://www.medworm.com/index.php?rid=5626141&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6132598%26arnumber%3D6068236 This study develops a sparse-grid-based adaptive model predictive control (MPC) strategy to direct HL60 cellular differentiation. Sparse-grid sampling and interpolation support a computationally efficient adaptive MPC scheme in which multiple data-consistent regions of the model parameter space are identified and used to calculate a control compromise. The algorithm is evaluated in silico with structural model mismatch. Simulations demonstrate how the multiscenario control strategy more effectively manages the mismatch compared to a single scenario approach. Furthermore, the controller is evaluated in vitro to differentiate HL60 cells in both normal and perturbed environments. The controller-derived input sequence successfully achieves and sustains the specified target level of granulocyte... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5626141 Wed, 25 Jan 2012 14:46:09 +0100 5626141 http://www.medworm.com/index.php?rid=5626140&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6132598%26arnumber%3D6064878 Acquisition of noncontrast agent cine cardiac magnetic resonance (CMR) gated images through the cardiac cycle is, at present, a well-established part of examining cardiac global function. However, regional quantification is less well established. We propose a new automated framework for analyzing the wall thickness and thickening function on these images that consists of three main steps. First, inner and outer wall borders are segmented from their surrounding tissues with a geometric deformable model guided by a special stochastic speed relationship. The latter accounts for Markov-Gibbs shape and appearance models of the object-of-interest and its background. In the second step, point-to-point correspondences between the inner and outer borders are found by solving the Laplace equation an... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5626140 Wed, 25 Jan 2012 14:46:09 +0100 5626140 http://www.medworm.com/index.php?rid=5626139&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6132598%26arnumber%3D6062651 This study showed that the fluctuation pressure amplitude would be greatly reduced by using a large-scale, hemispherical phased array with a low f-number. (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5626139 Wed, 25 Jan 2012 14:46:09 +0100 5626139 http://www.medworm.com/index.php?rid=5626138&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6132598%26arnumber%3D6062650 Original adaptive line enhancer (ALE) is used for denoising periodic signals from white noise. ALE, however, relies mainly on second order similarity between the signal and its delayed version and is more effective when the signal is narrowband. A new ALE based on singular spectrum analysis (SSA) is proposed here. In this approach in the reconstruction stage of SSA, the eigentriples are adaptively selected (filtered) using the delayed version of the data. Unlike the conventional ALE where (second) order statistics are taken into account, here the full eigen-spectrum of the embedding matrix is exploited. Consequently, the system works for non-Gaussian noise and wideband periodic signals. By performing some experiments on synthetic signals it is demonstrated that the proposed system is very ... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5626138 Wed, 25 Jan 2012 14:46:09 +0100 5626138 http://www.medworm.com/index.php?rid=5626137&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6132598%26arnumber%3D6062389 In this paper, we propose an efficient dictionary learning algorithm for sparse representation of given data and suggest a way to apply this algorithm to 3-D medical image denoising. Our learning approach is composed of two main parts: sparse coding and dictionary updating. On the sparse coding stage, an efficient algorithm named multiple clusters pursuit (MCP) is proposed. The MCP first applies a dictionary structuring strategy to cluster the atoms with high coherence together, and then employs a multiple-selection strategy to select several competitive atoms at each iteration. These two strategies can greatly reduce the computation complexity of the MCP and assist it to obtain better sparse solution. On the dictionary updating stage, the alternating optimization that efficiently approxim... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5626137 Wed, 25 Jan 2012 14:46:08 +0100 5626137 http://www.medworm.com/index.php?rid=5626136&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6132598%26arnumber%3D6061948 In this study, electrostatic finite element modeling was used to assess the effect of different shield geometries on the leakage of an internally applied field and penetration of an externally applied field. “Switching OFF” the shield by electrically disconnecting shield faces from each other was shown to significantly increase external field penetration. Applying this model to defibrillation, we looked at the effect of spacing and size of shield panels to maximize the ability to deliver an external defibrillation shock to the heart when shield panels are disconnected while providing acceptably low leakage of internal defibrillation shocks to avoid painful skeletal muscle capture when shield panels are connected. This analysis may be useful for designing internal defibrillato... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5626136 Wed, 25 Jan 2012 14:46:08 +0100 5626136 http://www.medworm.com/index.php?rid=5626135&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6132598%26arnumber%3D6060896 A multisite, vibrotactile sensory substitution system, that could be used in conjunction with artificial touch sensors in multifingered prostheses, to deliver sensory feedback to upper limb amputees is presented. The system is based on a low cost/power/size smart architecture of off-the-shelf miniaturized vibration motors; the main novelty is that it is able to generate stimuli where both vibration amplitude and frequency as well as beat interference can be modulated. This paper is aimed at evaluating this system by investigating the capability of healthy volunteers to perceive—on their forearms—vibrations with different amplitudes and/or frequencies. In addition, the ability of subjects in spatially discriminating stimulations on three forearm sites and recognizing six diffe... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5626135 Wed, 25 Jan 2012 14:46:08 +0100 5626135 http://www.medworm.com/index.php?rid=5626134&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6132598%26arnumber%3D6060897 To avoid or minimize postimplantation injury as a result of brain micromotion relative to the skull, a flexible multichannel polyimide (PI) cable was designed and microfabricated for data and power transmission between an intracranial IC recording from a neural probe array and an extracranial IC exchanging power and data wirelessly with an external unit. Surface characteristics, electrical properties, and cytocompatibility of the PI ribbon cable were investigated in this study. Scanning electron microscopic examination and atomic force microscopy analyses showed that the surface of the PI ribbon cable became significantly rougher due to the reactive oxygen ion etching process to open bonding pads. The enhanced surface roughness was also responsible for the increase in wettability and water... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5626134 Wed, 25 Jan 2012 14:46:08 +0100 5626134 http://www.medworm.com/index.php?rid=5626133&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6132598%26arnumber%3D6058630 A four-shell head phantom has been built and characterized. Its structure is similar to that of nonhomogeneous concentric shell domains used by numerical solvers that better approximate current distribution than phantoms currently used to validate electrical impedance tomography systems. Each shell represents a head tissue, namely, skin, skull, cerebrospinal fluid, and brain. A novel technique, which employs a volume conductive impermeable film, has been implemented to prevent ion diffusion between different agar regions without affecting current distribution inside the phantom. Comparisons between simulations and phantom measurements performed over four days are given to prove both the adherence to the model in the frequency range between 10 kHz and 1 MHz and its long-term stability. (Sou... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5626133 Wed, 25 Jan 2012 14:46:08 +0100 5626133 http://www.medworm.com/index.php?rid=5626132&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6132598%26arnumber%3D6054018 We report the development of an aqueous buffer system tailored to the fluidic and hemodynamic requirements of our recently reported microfluidic platelet dynamic assay device, which uses hydrodynamic focusing to “shape” a blood sample into a thin flowing layer adjacent to its protein-functionalized surface. By matching the dynamic viscosity of whole blood (3.13 ± 0.08 mPa·s, from healthy donors), the selected buffer minimizes interfacial fluid mixing and better controls shear rate within the device, permitting platelet/protein-surface interaction assays with as little as 50 μL of whole blood. Buffers containing the viscosity-enhancing components bovine serum albumin (BSA), gelofusine/glycine, or histopaque (Ficoll gradient solution) were fou... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5626132 Wed, 25 Jan 2012 14:46:08 +0100 5626132 http://www.medworm.com/index.php?rid=5626131&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6132598%26arnumber%3D6054017 In this study, we propose a new framework to enhance the performance of the spherical deconvolution (SD) approach in low angular resolution DWI by employing a single channel blind source separation (BSS) technique to decompose the fODF initially estimated by SD such that the desired fODF can be extracted from the noisy background. The results based on numerical simulations and two phantom datasets demonstrate that the proposed method achieves better performance than SD in terms of robustness to noise and variation in b-values. In addition, the results show that the proposed method has the potential to be applied to low angular resolution DWI which is commonly used in clinical studies. (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5626131 Wed, 25 Jan 2012 14:46:08 +0100 5626131 http://www.medworm.com/index.php?rid=5626130&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6132598%26arnumber%3D6051474 Capsule endoscopy (CE) provides noninvasive access to a large part of the small bowel that is otherwise inaccessible without invasive and traumatic treatment. However, it also produces large amounts of data (approximately 50 000 images) that must be then manually reviewed by a clinician. Such large datasets provide an opportunity for application of image analysis and supervised learning methods. Automated analysis of CE images has only focused on detection, and often only for bleeding. Compared to these detection approaches, we explored assessment of discrete disease for lesions created by mucosal inflammation in Crohn’s disease (CD). Our work is the first study to systematically explore supervised classification for CD lesions, a classifier cascade to classify discrete lesio... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5626130 Wed, 25 Jan 2012 14:46:08 +0100 5626130 http://www.medworm.com/index.php?rid=5626129&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6132598%26arnumber%3D6051472 We developed and validated silicon-based neural probes for neural stimulating and recording in long-term implantation in the brain. The probes combine the deep reactive ion etching process and mechanical shaping of their tip region, yielding a mechanically sturdy shank with a sharpened tip to reduce insertion force into the brain and spinal cord, particularly, with multiple shanks in the same array. The arrays’ insertion forces have been quantified in vitro. Five consecutive chronically-implanted devices were fully functional from 3 to 18 months. The microelectrode sites were electroplated with iridium oxide, and the charge injection capacity measurements were performed both in vitro and after implantation in the adult feline brain. The functionality of the chronic array was validat... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5626129 Wed, 25 Jan 2012 14:46:08 +0100 5626129 http://www.medworm.com/index.php?rid=5626128&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6132598%26arnumber%3D6045322 In this study, temperatures were measured at multiple locations on the retina while the retina was heated in cadaver and in vivo preparations using a variety of prosthesis implantation sites. A finite element thermal model of the cat eye was also created and validated by the cadaver and in vivo tests, allowing for a much larger spectrum of thermal influences to be evaluated without additional animal experimentation. To ensure that retinal tissue temperatures are not increased by more than 2 °C, a 5 mm × 5 mm, suprachoroidally implanted heating element must not dissipate more than 135 mW (5.4 mW/mm $^2$). (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5626128 Wed, 25 Jan 2012 14:46:08 +0100 5626128 http://www.medworm.com/index.php?rid=5626127&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6132598%26arnumber%3D6099602 The measurement of interaction forces in minimally invasive surgical devices, sensorized with photonic crystal fiber (PCF) sensors, is presented in this paper. Two types of PCF sensors are used: a tapered PCF interferometer and a microhole-collapsed PCF interferometer for the detection of interaction forces generated in surgical devices without the influence of ambient temperature variation. The demonstration devices used for force characterization are a laparoscopic scissor and a standard surgical scissor blade. The force sensitivity of each sensorized blade is examined and compared with fiber Bragg grating (FBG)-sensorized blades. Results show that the PCF-sensorized surgical blades outperform the blades fitted with the FBG sensors during static load measurement. (Source: IEEE Transactio... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5626127 Wed, 25 Jan 2012 14:46:07 +0100 5626127 http://www.medworm.com/index.php?rid=5626126&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6132598%26arnumber%3D6025273 This study presents a methodology for applying the forced-oscillation technique in total liquid ventilation. It mainly consists of applying sinusoidal volumetric excitation to the respiratory system, and determining the transfer function between the delivered flow rate and resulting airway pressure. The investigated frequency range was $fin left[0.05, 4right]$ Hz at a constant flow amplitude of 7.5 mL/s. The five parameters of a fractional order lung model, the existing “5-parameter constant-phase model,” were identified based on measured impedance spectra. The identification method was validated in silico on computer-generated datasets and the overall process was validated in vitro on a simplified single-compartment mechanical lung model. In vivo data on ten newborn lambs su... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5626126 Wed, 25 Jan 2012 14:46:07 +0100 5626126 http://www.medworm.com/index.php?rid=5626125&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6132598%26arnumber%3D6020755 Despite the commonly accepted notion that action potential duration (APD) is distributed heterogeneously throughout the ventricles and that the associated dispersion of repolarization is mainly responsible for the shape of the T-wave, its concordance and exact morphology are still not completely understood. This paper evaluated the T-waves for different previously measured heterogeneous ion channel distributions. To this end, cardiac activation and repolarization was simulated on a high resolution and anisotropic biventricular model of a volunteer. From the same volunteer, multichannel ECG data were obtained. Resulting transmembrane voltage distributions for the previously measured heterogeneous ion channel expressions were used to calculate the ECG and the simulated T-wave was compared to... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5626125 Wed, 25 Jan 2012 14:46:07 +0100 5626125 http://www.medworm.com/index.php?rid=5626124&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6132598%26arnumber%3D6059499 Correct placement of the electrode is crucial for cochlear implantation (CI) surgery. It determines the access to the auditory nerve and subsequent hearing performance. Here, we propose an objective measures tool that can partially verify the electrode position. The intracochlear spread of the electrical fields is measured and analyzed by means of multidimensional scaling resulting in an intuitive visual representation. The user can then detect major issues, such as electrode foldover or ossification. Other implantation issues, such as electrode migration into the scala vestibuli, may not significantly alter the electrical conduction pattern and remain undetected. Still, as the measurement is quick and readily available, it may be a valuable intraoperative verification tool. (Source: IEEE ... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5626124 Wed, 25 Jan 2012 14:46:07 +0100 5626124 http://www.medworm.com/index.php?rid=5626123&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6132598%26arnumber%3D5963704 We show that a mobile phone can serve as an accurate monitor for several physiological variables, based on its ability to record and analyze the varying color signals of a fingertip placed in contact with its optical sensor. We confirm the accuracy of measurements of breathing rate, cardiac R-R intervals, and blood oxygen saturation, by comparisons to standard methods for making such measurements (respiration belts, ECGs, and pulse-oximeters, respectively). Measurement of respiratory rate uses a previously reported algorithm developed for use with a pulse-oximeter, based on amplitude and frequency modulation sequences within the light signal. We note that this technology can also be used with recently developed algorithms for detection of atrial fibrillation or blood loss. (Source: IEEE Tr... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5626123 Wed, 25 Jan 2012 14:46:07 +0100 5626123 http://www.medworm.com/index.php?rid=5626122&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6132598%26arnumber%3D6132600 (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5626122 Wed, 25 Jan 2012 14:46:07 +0100 5626122 http://www.medworm.com/index.php?rid=5626121&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6132598%26arnumber%3D6132601 (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5626121 Wed, 25 Jan 2012 14:46:07 +0100 5626121 http://www.medworm.com/index.php?rid=5626120&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6132598%26arnumber%3D6132599 (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5626120 Wed, 25 Jan 2012 14:46:07 +0100 5626120 http://www.medworm.com/index.php?rid=5570423&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6106028%26arnumber%3D5955097 In this study, simultaneous acquisition of both $^1$H and $^{13}$ C signals after contrast agent injection is used to resolve specific compartments to improve the accuracy of the modeling. We demonstrate a novel technique to provide contrast to the intracellular compartments by sequential injection of HP [1-$^{13}$C] pyruvate followed by gadolinium-chelate to provide T$_1$-shortening to extra-cellular compartments. A kinetic model that distinguishes the intracellular space and includes the T $_1$-shortening effect of the gadolinium chelate can then be used to directly measure the intracellular $^{13}$C kinetics. (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5570423 Sun, 01 Jan 2012 05:00:00 +0100 5570423 http://www.medworm.com/index.php?rid=5521860&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6106028%26arnumber%3D6106059 (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5521860 Wed, 21 Dec 2011 00:24:58 +0100 5521860 http://www.medworm.com/index.php?rid=5521859&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6106028%26arnumber%3D6106060 (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5521859 Wed, 21 Dec 2011 00:24:58 +0100 5521859 http://www.medworm.com/index.php?rid=5521858&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6106028%26arnumber%3D6106061 (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5521858 Wed, 21 Dec 2011 00:24:58 +0100 5521858 http://www.medworm.com/index.php?rid=5521857&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6106028%26arnumber%3D6062649 In this study, we use these GKPs to automatically detect and estimate tongue positions, and develop a tongue–machine interface. We show that a specific configuration of electrode placement yields discriminative GKPs that vary depending on the direction of the tongue. We develop a linear model to determine the direction of tongue from GKPs, where we seek linear features that are robust to a baseline drift problem by maximizing the ratio of intertask covariance to intersession covariance. We apply our method to the task of wheelchair control, developing a tongue–machine interface for wheelchair control, referred to as tongue-rudder. A teeth clenching detection system, using electromyography, was also implemented in the system in order to assign teeth clenching as the stop comma... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5521857 Wed, 21 Dec 2011 00:24:57 +0100 5521857 http://www.medworm.com/index.php?rid=5521856&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6106028%26arnumber%3D6062388 In recent years, there has been a great effort in the research of implementing automated diagnostic systems for tissue images. One major challenge in this implementation is to design systems that are robust to image variations. In order to meet this challenge, it is important to learn the systems on a large number of labeled images from a different range of variation. However, acquiring labeled images is quite difficult in this domain, and hence, the labeled training data are typically very limited. Although the issue of having limited labeled data is acknowledged by many researchers, it has rarely been considered in the system design. This paper successfully addresses this issue, introducing a new resampling framework to simulate variations in tissue images. This framework generates multi... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5521856 Wed, 21 Dec 2011 00:24:57 +0100 5521856 http://www.medworm.com/index.php?rid=5521855&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6106028%26arnumber%3D6059497 DNA copy number alterations (CNAs) can cause genetic diseases, and studies have revealed a relationship between CNAs and gene expression; however, the manner in which CNAs relate to gene expression and what regulatory mechanisms underlying the relationship remain unclear. In many instances, real data have revealed a nonlinear relationship between copy number and gene expression. In this paper, queueing theory is used to model this relationship, with the basic structural parameters involving transcription factor (TF) arrival and departure rates. A key finding is that the ratio of TF arrival rate to TF departure rate is critical: small and large ratios corresponding to nonlinear and linear relationships, respectively. Indeed, copy number amplifications do not necessarily lead to expression i... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5521855 Wed, 21 Dec 2011 00:24:57 +0100 5521855 http://www.medworm.com/index.php?rid=5521854&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6106028%26arnumber%3D6051473 We present a new way to securely mount a medical microwave antenna onto the human body for improved in vivo temperature measurements by microwave radiometry. A low cost and simple vacuum pressure source is used to provide suction (negative pressure) on the aperture of an elliptical antenna with vacuum chamber cavity backing. The concept offers improved electromechanical coupling between the antenna surface and the skin of the body. The proposed solution is evaluated experimentally to test repeatability of radiometric temperature measurements by remounting the antenna many times in one sequence on a given anatomical location. Four representative locations (hand, belly, hip, and chest) were used to test the suction antenna concept against anatomical curvature and load variations. Statistical... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5521854 Wed, 21 Dec 2011 00:24:57 +0100 5521854 http://www.medworm.com/index.php?rid=5521853&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6106028%26arnumber%3D6046115 We have developed an inexpensive PC camera-based system to measure sensor position and to track head motion during magnetoencephalography recordings. The system employs mirrors to triangulate the position of markers using a single camera. Sensor position measurement and head tracking can be performed without the need to manually digitize markers or fiducial points. The system is capable of measuring relative 3-D position within the required volume of interest with an accuracy of ∼450 μm and can be constructed for approximately $150. (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5521853 Wed, 21 Dec 2011 00:24:57 +0100 5521853 http://www.medworm.com/index.php?rid=5521852&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6106028%26arnumber%3D6043866 Vibroacoustography (VA) is an ultrasound-based modality sensitive to stiffness and free from speckle and possesses some advantages over conventional ultrasound imaging in terms of image quality. The primary objective here is to show its feasibility in detecting/imaging kidney stones (KSs) in vitro . In VA, two intersecting ultrasound beams driven at two different frequencies f$_1$ and f$_2$, respectively, are focused within a freshly excised porcine kidney attached to a solid frame with elastic rubber bands, while the amplitude of the acoustic emission pressure field produced at the difference frequency Δ f = $vert $ f$_1$ − f$_2$ $vert $ is detected by a low-frequency hydrophone. The received low-frequency signal is bandpass filtered and amplified, then digitized by a... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5521852 Wed, 21 Dec 2011 00:24:57 +0100 5521852 http://www.medworm.com/index.php?rid=5521851&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6106028%26arnumber%3D6036156 This paper proposes a method for the automatic classification of heartbeats in an ECG signal. Since this task has specific characteristics such as time dependences between observations and a strong class unbalance, a specific classifier is proposed and evaluated on real ECG signals from the MIT arrhythmia database. This classifier is a weighted variant of the conditional random fields classifier. Experiments show that the proposed method outperforms previously reported heartbeat classification methods, especially for the pathological heartbeats. (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5521851 Wed, 21 Dec 2011 00:24:57 +0100 5521851 http://www.medworm.com/index.php?rid=5521850&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6106028%26arnumber%3D6036158 We present a novel generic clinical decision support system, which models a patient's disease state statistically from heterogeneous multiscale data. Its goal is to aid in diagnostic work by analyzing all available patient data and highlighting the relevant information to the clinician. The system is evaluated by applying it to several medical datasets and demonstrated by implementing a novel clinical decision support tool for early prediction of Alzheimer's disease. (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5521850 Wed, 21 Dec 2011 00:24:57 +0100 5521850 http://www.medworm.com/index.php?rid=5521849&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6106028%26arnumber%3D6041015 Scaling of action potential (AP) duration (APD) in mammals of different size is a rather complex phenomenon, dominated by a regulatory type mechanism of ion channels expression. By means of simulations performed on six published mathematical models of cardiac ventricular APs of different mammals, it is shown that AP repolarization is autoregenerative in its later phase (ARRP) and that the duration of such phase scales linearly with APD. For each AP, a 3-D instantaneous time–voltage–current surface is constructed, which has been recently described in a more simplified model. This representation allows us to measure ARRP and to study the contribution to it for different ion currents. It has been found that the existence of an ARRP is not intrinsic to cardiac models formulation;... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5521849 Wed, 21 Dec 2011 00:24:57 +0100 5521849 http://www.medworm.com/index.php?rid=5521848&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6106028%26arnumber%3D6035761 In many applications requiring the study of the surface myoelectric signal (SMES) acquired in dynamic conditions, it is essential to have a quantitative evaluation of the quality of the collected signals. When the activation pattern of a muscle has to be obtained by means of single- or double-threshold statistical detectors, the background noise level e$_{rm noise}$ of the signal is a necessary input parameter. Moreover, the detection strategy of double-threshold detectors may be properly tuned when the SNR and the duty cycle (DC) of the signal are known. The aim of this paper is to present an algorithm for the estimation of e $_{rm noise}$, SNR, and DC of an SMES collected during cyclic movements. The algorithm is validated on synthetic signals with statistical properties similar to those... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5521848 Wed, 21 Dec 2011 00:24:57 +0100 5521848 http://www.medworm.com/index.php?rid=5521847&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6106028%26arnumber%3D6032733 As part of clinical diagnosis, a clinician is required to detect disease causing antigens, bacteria, or viruses in serum, saliva, or other biological samples. Usually, this requires the sample to be sent to a pathology laboratory for analysis. Silicon nanowires can be made into sensitive molecular sensors. When being functionalized with antibodies, they are capable of detecting femto molar concentrations of antigens in real time. Biological molecules at a pH different from their isoelectric point exhibit a net charge. When an antigen attaches to the antibody on the nanowire, the net charged on the antigen displaces free carriers in the nanowire changing its conductance. To date, detection methods have been based upon directly measuring the change in dc conductance. This is difficult and re... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5521847 Wed, 21 Dec 2011 00:24:57 +0100 5521847 http://www.medworm.com/index.php?rid=5521846&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6106028%26arnumber%3D6032732 The surface electromyogram (EMG) from biceps and triceps muscles of 33 subjects was related to elbow torque, contrasting EMG amplitude (EMGσ) estimation processors, linear/nonlinear model structures, and system identification techniques. Torque estimation was improved by 1) advanced EMGσ processors (i.e., whitened, multiple-channel signals); 2) longer duration training sets (52 s versus 26 s); and 3) determination of model parameters via pseudoinverse and ridge regression methods. Dynamic, nonlinear parametric models that included second- or third-degree polynomial functions of EMGσ outperformed linear models and Hammerstein/Weiner models. A minimum error of 4.65 ± 3.6% maximum voluntary contraction (MVC) flexion was attained using a third-degree polynomi... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5521846 Wed, 21 Dec 2011 00:24:57 +0100 5521846 http://www.medworm.com/index.php?rid=5521845&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6106028%26arnumber%3D6031907 Recent work employing the computational fluid–particle modeling of the hepatic arteries has identified a correlation between particle release position and downstream branch distribution for direct tumor-targeting in radioembolization procedures. An experimental model has been constructed to evaluate the underlying simulation theory and determine its feasibility for future clinical use. A scaled model of a generalized hepatic system with a single inlet and five outlet branches was fabricated to replicate the fluid dynamics in the hepatic arteries of diseased livers. Assuming steady flow, neutrally buoyant microspheres were released from controlled locations within the inlet of the model and the resulting output distributions were recorded. Fluid and particle transport simulations wer... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5521845 Wed, 21 Dec 2011 00:24:57 +0100 5521845 http://www.medworm.com/index.php?rid=5521844&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6106028%26arnumber%3D6029418 The current literature contains extensive research on peripheral nerve interfaces, including both extraneural and intrafascicular electrodes. Interfascicular electrodes, which are in-between these two with respect to nerve fiber proximity have, however, received little interest. In this proof-of-concept study, an interfascicular electrode was designed to be implanted in the sciatic nerve and activate the tibial and peroneal nerves selectively of each other, and it was tested in acute experiments on nine anaesthetized rabbits. The electrode was inserted without difficulty between the fascicles using blunt glass tools, which could easily penetrate the epineurium but not the perineurium. Selective activation of all tibial and peroneal nerves in the nine animals was achieved with high selectiv... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5521844 Wed, 21 Dec 2011 00:24:56 +0100 5521844 http://www.medworm.com/index.php?rid=5521843&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6106028%26arnumber%3D6026913 Motor unit potential trains (MUPTs) extracted via electromyographic (EMG) signal decomposition can aid in the diagnosis of neuromuscular disorders and the study of the neural control of movement, but only if they are valid. In this paper, support vector machine (SVM)-based supervised classifiers are proposed to estimate the validity of extracted MUPTs. The classifiers use either the MU firing pattern or the MUP shape consistency of an MUPT, or both, to estimate its validity. The developed classifiers estimate the class label of an MUPT (i.e., valid/invalid) and a degree of support for the decision being made. A single SVM that estimates the validity of a given MUPT using extracted MU firing pattern and MUP shape features was investigated. In addition, the effectiveness of multiclassifier t... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5521843 Wed, 21 Dec 2011 00:24:56 +0100 5521843 http://www.medworm.com/index.php?rid=5521842&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6106028%26arnumber%3D6029417 This study assessed the ability of the tongue tip to accurately select intraoral targets embedded in an upper palatal tongue–computer interface, using 18 able-bodied volunteers. Four performance measures, based on modifications to Fitts's Law, were determined for three different tongue–computer interface layouts. The layouts differed with respect to number and location of the targets in the palatal interface. Assessment of intraoral target selection speed and accuracy revealed that performance was indeed dependent on the location and distance between the targets. Performances were faster and more accurate for targets located farther away from the base of the tongue in comparison to posterior and medial targets. A regression model was built, which predicted intraoral ta... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5521842 Wed, 21 Dec 2011 00:24:56 +0100 5521842 http://www.medworm.com/index.php?rid=5521841&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6106028%26arnumber%3D6024445 In this study, a novel thermal management system (TMS) is developed for the minimization of thermal spread created by a monopolar electrosurgical device, the most commonly used surgical instrument. The phenomenon of resistive heating of tissue is modeled using the finite-element method (FEM) to analyze the electrical potential and temperature distributions in biological tissue subjected to heat generation during monopolar electrosurgery. Ex vivo experiments are used to validate the FEM by comparing the model predicted and experimentally measured temperatures. The predicted FEM maximum temperature 1.0 mm adjacent to the electrode is within 1% of the experimentally measured maximum temperature using a standard monopolar pencil electrode. A TMS consisting of adjacent cooling cha... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5521841 Wed, 21 Dec 2011 00:24:56 +0100 5521841 http://www.medworm.com/index.php?rid=5521840&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6106028%26arnumber%3D6022758 In this paper, quantitative dielectric image reconstruction based on broadband microwave measurements is investigated. A time-domain-based algorithm is derived where Debye model parameters are reconstructed in order to take into account the strong dispersive behavior found in biological tissue. The algorithm is tested with experimental and numerical data in order to verify the algorithm and to investigate improvements in the reconstructed image resulting from the improved description of the dielectric properties of the tissue when using broadband data. The comparison is made in relation to the more commonly used conductivity model. For the evaluation, two examples were considered, the first was a lossy saline solution and the second was less lossy tap water. Both liquids are strongly dispe... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5521840 Wed, 21 Dec 2011 00:24:56 +0100 5521840 http://www.medworm.com/index.php?rid=5521839&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6106028%26arnumber%3D6020751 To develop noninvasive diagnosis of malaria, we studied the light-scattering pattern of healthy and 2% Plasmodium falciparum malaria parasitized red blood cells. By measuring the wavelength-dependent scattering at discrete angles of both forward and backward directions, we found that the signal can clearly distinguish between healthy and ring stage infected red blood cells. In particular, we demonstrated the first backward scattering measurement, which enables elastic light scattering as a promising noninvasive diagnostic tool for malaria. (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5521839 Wed, 21 Dec 2011 00:24:56 +0100 5521839 http://www.medworm.com/index.php?rid=5521838&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6106028%26arnumber%3D6019022 We present a novel approach for automatic estimation of the AHI from nocturnal oxygen saturation (SaO$_2$) recordings and the results of an assessment study designed to characterize its performance. A set of 240 SaO$_2$ signals was available for the assessment study. The data were divided into training (96 signals) and test (144 signals) sets for model optimization and validation, respectively. Fourteen time-domain and frequency-domain features were used to quantify the effect of SAHS on SaO$_2$ recordings. Regression analysis was performed to estimate the functional relationship between the extracted features and the AHI. Multiple linear regression (MLR) and multilayer perceptron (MLP) neural networks were evaluated. The MLP algorithm achieved the highest performance with an intraclass co... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5521838 Wed, 21 Dec 2011 00:24:56 +0100 5521838 http://www.medworm.com/index.php?rid=5521837&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6106028%26arnumber%3D6018285 In this study, the target selection or rejection functionality is implemented using a hybrid feature from motor imagery and the P300 potential. Specifically, to select the target of interest, the user must focus his or her attention on a flashing button to evoke the P300 potential, while simultaneously maintaining an idle state of motor imagery. Otherwise, the user performs left-/right-hand motor imagery without paying attention to any buttons to reject the target. Our data analysis and online experimental results validate the effectiveness of our approach. The proposed hybrid feature is shown to be more effective than the use of either the motor imagery feature or the P300 feature alone. Eleven subjects attended our online experiment, in which a trial involved sequential 2-D cursor moveme... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5521837 Wed, 21 Dec 2011 00:24:56 +0100 5521837 http://www.medworm.com/index.php?rid=5521836&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6106028%26arnumber%3D6020752 We present a comprehensive comparison between the techniques in terms of robustness, as computed by tracking errors, and accuracy, as computed by TRE using two independent approaches. (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5521836 Wed, 21 Dec 2011 00:24:56 +0100 5521836 http://www.medworm.com/index.php?rid=5521835&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6106028%26arnumber%3D6016214 The purpose of this study was to develop a technique to measure the dielectric properties of biological tissues with an interstitial dipole antenna based upon previous efforts for open-ended coaxial probes. The primary motivation for this technique is to facilitate treatment monitoring during microwave tumor ablation by utilizing the heating antenna without additional intervention or interruption of the treatment. The complex permittivity of a tissue volume surrounding the antenna was calculated from reflection coefficients measured after high-temperature microwave heating by using a rational function model of the antenna's input admittance. Three referencing liquids were needed for measurement calibration. The dielectric measurement technique was validated ex vivo in normal and abl... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5521835 Wed, 21 Dec 2011 00:24:56 +0100 5521835 http://www.medworm.com/index.php?rid=5521834&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6106028%26arnumber%3D5955099 High-frequency chest compression (HFCC), using an appropriate source (pump) waveform for frequencies at or above 3 Hz, can enhance pulmonary clearance for patients with cystic fibrosis (CF) and chronic obstructive pulmonary disease (COPD). Using a trapezoidal HFCC source pressure waveform, secretion of water from epithelial tissue and transport of mucus through lung airways can be enhanced for patients with CF and COPD. At frequencies below 3 Hz, low-frequency chest compression (LFCC) appears to have a significant impact on the cardiovascular system. For a trapezoidal source pressure waveform at frequencies close to 1 Hz, LFCC produces amplitude or intensity variations in various components of the electrocardiogram time-domain waveform, produces changes at very low fre... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5521834 Wed, 21 Dec 2011 00:24:56 +0100 5521834 http://www.medworm.com/index.php?rid=5521833&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6106028%26arnumber%3D5954157 A system for the realtime generation and control of multiple-focus ultrasound phased-array heating patterns is presented. The system employs a 1-MHz, 64-element array and driving electronics capable of fine spatial and temporal control of the heating pattern. The driver is integrated with a realtime 2-D temperature imaging system implemented on a commercial scanner. The coordinates of the temperature control points are defined on B-mode guidance images from the scanner, together with the temperature set points and controller parameters. The temperature at each point is controlled by an independent proportional, integral, and derivative controller that determines the focal intensity at that point. Optimal multiple-focus synthesis is applied to generate the desired heating pattern at the con... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5521833 Wed, 21 Dec 2011 00:24:56 +0100 5521833 http://www.medworm.com/index.php?rid=5521832&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6106028%26arnumber%3D5756457 Diffuse optical multipatch technique is used to assess spatial variations in absorption and scattering in biological tissue, by monitoring changes in the concentration of oxyhemoglobin and deoxyhemoglobin. In our preliminary study, the temporal tracings of tissue oxygenation are measured using diffuse optical multipatch measurement and a venous occlusion test, employing normal subjects and ICU patients suffering from sepsis and heart failure. In experiments, obvious differences in tissue oxygenation signals were observed among all three groups. This paper discusses the physiological relevance of tissue oxygenation with respect to disease. (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5521832 Wed, 21 Dec 2011 00:24:56 +0100 5521832 http://www.medworm.com/index.php?rid=5521831&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6106028%26arnumber%3D5719295 Ventricular fibrillation (VF) is the primary arrhythmic event in the majority of patients suffering from sudden cardiac arrest. Attention has been focused on this particular rhythm since it is recognized that prompt therapy, especially electrical defibrillation, may lead to a successful outcome. However, current versions of automated external defibrillators (AEDs) mandate repetitive interruptions of chest compression for rhythm analyses since artifacts produced by chest compression during cardiopulmonary resuscitation (CPR) preclude reliable electrocardiographic (ECG) rhythm analysis. Yet, repetitive interruptions in chest compression are detrimental to the success of defibrillation. The capability for rhythm analysis without requiring “hands-off” intervals will allow for mor... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5521831 Wed, 21 Dec 2011 00:24:55 +0100 5521831 http://www.medworm.com/index.php?rid=5521830&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6106028%26arnumber%3D5680601 In this study, the effects of LG-HMF on the activity, morphology, and cytoskeleton (actin filament, microtubules, and vimentin intermediate filaments) in osteocyte - like cell line MLO-Y4 were detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) methods, hematoxylin–eosin (HE) staining, and laser scanning confocal microscopy (LSCM), respectively. The changes induced by LG-HMF in distribution and expression of focal adhesion (FA) proteins, including vinculin, paxillin, and talin in MLO-Y4 were determined by LSCM and Western blotting. The results showed that LG-HMF produced by superconducting magnet had no lethal effects on MLO-Y4. Compared to control, diamagnetic levitation (μg) affected MLO-Y4 morphology, nucleus size, cytoskeleton architecture, and ... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5521830 Wed, 21 Dec 2011 00:24:55 +0100 5521830 http://www.medworm.com/index.php?rid=5521829&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6106028%26arnumber%3D5682010 In this study, we present an advanced Bayesian framework for the analysis of functional magnetic resonance imaging (fMRI) data that simultaneously employs both spatial and sparse properties. The basic building block of our method is the general linear regression model that constitutes a well-known probabilistic approach. By treating regression coefficients as random variables, we can apply an enhanced Gibbs distribution function that captures spatial constrains and at the same time allows sparse representation of fMRI time series. The proposed scheme is described as a maximum a posteriori approach, where the known expectation maximization algorithm is applied offering closed-form update equations for the model parameters. We have demonstrated that our method produces improved performance a... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5521829 Wed, 21 Dec 2011 00:24:55 +0100 5521829 http://www.medworm.com/index.php?rid=5521828&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6106028%26arnumber%3D5966320 This letter presents an in silico evaluation method of glucose control protocols for critically ill patients with hyperglycemia. Although various glucose control protocols were introduced and investigated in clinical trials, development and validation of a novel glucose control protocol for critically ill patients require too much time and resources in clinical evaluation. We employed a virtual patient model of the critically ill patient with hyperglycemia and evaluated the clinically investigated glucose control protocols in a computational environment. The three-day simulation results presented the time profiles of glucose and insulin concentrations, the amount of enteral feed and intravenous bolus of glucose, and the intravenous insulin infusion rate. The hyperglycemia and hypoglycemia ... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5521828 Wed, 21 Dec 2011 00:24:55 +0100 5521828 http://www.medworm.com/index.php?rid=5521827&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6106028%26arnumber%3D6003766 In this study, we use multiscale mesoscopic bridging procedure of the finite elements (FE) coupled with dissipative particle dynamics (DPD) and lattice Boltzmann (LB) method to model the motion of circular and elliptical particles in a 2-D laminar flow. Four examples are considered: 1) one sedimenting cylinder in a channel, 2) two sedimenting cylinders in a channel, 3) motion of four elliptical particles in a linear shear flow, and 4) motion of circular and elliptical particle in the arterial bifurcation geometry. A good agreement with solution from the literature available was found. These results show that the multiscale approach with coupled FE and DPD/LB methods can effectively be applied to model motion of micro/nanoparticles for a drug delivery system. (Source: IEEE Transactions on B... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5521827 Wed, 21 Dec 2011 00:24:55 +0100 5521827 http://www.medworm.com/index.php?rid=5521826&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6106028%26arnumber%3D5955097 In this study, simultaneous acquisition of both $^1$H and $^{13}$ C signals after contrast agent injection is used to resolve specific compartments to improve the accuracy of the modeling. We demonstrate a novel technique to provide contrast to the intracellular compartments by sequential injection of HP [1-$^{13}$C] pyruvate followed by gadolinium-chelate to provide T$_1$-shortening to extra-cellular compartments. A kinetic model that distinguishes the intracellular space and includes the T $_1$-shortening effect of the gadolinium chelate can then be used to directly measure the intracellular $^{13}$C kinetics. (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5521826 Wed, 21 Dec 2011 00:24:55 +0100 5521826 http://www.medworm.com/index.php?rid=5521825&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6106028%26arnumber%3D6015536 Practically, all chronic diseases are characterized by tissue remodeling that alters organ and cellular function through changes to normal organ architecture. Some morphometric alterations become irreversible and account for disease progression even on cellular levels. Early diagnostics to categorize tissue alterations, as well as monitoring progression or remission of disturbed cytoarchitecture upon treatment in the same individual, are a new emerging field. They strongly challenge spatial resolution and require advanced imaging techniques and strategies for detecting morphological changes. We use a combined second harmonic generation (SHG) microscopy and automated image processing approach to quantify morphology in an animal model of inherited Duchenne muscular dystrophy ( mdx mouse) wit... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5521825 Wed, 21 Dec 2011 00:24:55 +0100 5521825 http://www.medworm.com/index.php?rid=5521824&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6106028%26arnumber%3D6020750 Several groups in neurobiology have embarked into deciphering the brain circuitry using large-scale imaging of a mouse brain and manual tracing of the connections between neurons. Creating a graph of the brain circuitry, also called a connectome, could have a huge impact on the understanding of neurodegenerative diseases such as Alzheimer’s disease. Although considerably smaller than a human brain, a mouse brain already exhibits one billion connections and manually tracing the connectome of a mouse brain can only be achieved partially. This paper proposes to scale up the tracing by using automated image segmentation and a parallel computing approach designed for domain experts. We explain the design decisions behind our parallel approach and we present our results for the segmentati... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5521824 Wed, 21 Dec 2011 00:24:55 +0100 5521824 http://www.medworm.com/index.php?rid=5521823&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6106028%26arnumber%3D6042325 Cultures of cortical neurons grown on multielectrode arrays exhibit spontaneous, robust, and recurrent patterns of highly synchronous activity called bursts. These bursts play a crucial role in the development and topological self-organization of neuronal networks. Thus, understanding the evolution of synchrony within these bursts could give insight into network growth and the functional processes involved in learning and memory. Functional connectivity networks can be constructed by observing patterns of synchrony that evolve during bursts. To capture this evolution, a modeling approach is adopted using a framework of emergent evolving complex networks and, through taking advantage of the multiple time scales of the system, aims to show the importance of sequential and ordered synchroniza... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5521823 Wed, 21 Dec 2011 00:24:55 +0100 5521823 http://www.medworm.com/index.php?rid=5521822&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6106028%26arnumber%3D5970097 Image-based modeling of tumor growth combines methods from cancer simulation and medical imaging. In this context, we present a novel approach to adapt a healthy brain atlas to MR images of tumor patients. In order to establish correspondence between a healthy atlas and a pathologic patient image, tumor growth modeling in combination with registration algorithms is employed. In a first step, the tumor is grown in the atlas based on a new multiscale, multiphysics model including growth simulation from the cellular level up to the biomechanical level, accounting for cell proliferation and tissue deformations. Large-scale deformations are handled with an Eulerian approach for finite element computations, which can operate directly on the image voxel mesh. Subsequently, dense correspondence be... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5521822 Wed, 21 Dec 2011 00:24:55 +0100 5521822 http://www.medworm.com/index.php?rid=5521821&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6106028%26arnumber%3D5930343 Personalization is a key aspect of biophysical models in order to impact clinical practice. In this paper, we propose a personalization method of electromechanical models of the heart from cine-MR images based on the adjoint method. After estimation of electrophysiological parameters, the cardiac motion is estimated based on a proactive electromechanical model. Then cardiac contractilities on two or three regions are estimated by minimizing the discrepancy between measured and simulation motion. Evaluation of the method on three patients with infarcted or dilated myocardium is provided. (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5521821 Wed, 21 Dec 2011 00:24:55 +0100 5521821 http://www.medworm.com/index.php?rid=5521820&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6106028%26arnumber%3D6003768 Cardiac fiber architecture plays an important role in the study of mechanical and electrical properties of the wall of the human heart, but still remains to be elucidated. This paper proposes to investigate, in a multiscale manner, how the arrangement patterns and morphological heterogeneity of cardiac myocytes influence the fibers orientation. To this end, different virtual cardiac fiber structures are modeled, and diffusion tensor imaging at multiple scales are simulated using the Monte Carlo method. The results show that the proposed modeling and simulation allow us to quantitatively describe the variation of the measured tissue properties (fiber orientation and fractional anisotropy) as a function of the observation scale. (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5521820 Wed, 21 Dec 2011 00:24:55 +0100 5521820 http://www.medworm.com/index.php?rid=5521819&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6106028%26arnumber%3D5958582 Multiscale entropy (MSE) has been widely used to quantify a system's complexity by taking into account the multiple time scales inherent in physiologic time series. The method, however, is biased toward the coarse scale, i.e., low-frequency components due to the progressive smoothing operations. In addition, the algorithm for extracting the different scales is not well adapted to nonlinear/nonstationary signals. In this letter, we introduce adaptive multiscale entropy (AME) measures in which the scales are adaptively derived directly from the data by virtue of recently developed multivariate empirical mode decomposition. Depending on the consecutive removal of low-frequency or high-frequency components, our AME can be estimated at either coarse-to-fine or fine-to-coarse scales over ... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5521819 Wed, 21 Dec 2011 00:24:55 +0100 5521819 http://www.medworm.com/index.php?rid=5521818&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6106028%26arnumber%3D6051471 Phase–amplitude cross-frequency coupling (CFC)—where the phase of a low-frequency signal modulates the amplitude or power of a high-frequency signal—is a topic of increasing interest in neuroscience. However, existing methods of assessing CFC are inherently bivariate and cannot estimate CFC between more than two signals at a time. Given the increase in multielectrode recordings, this is a strong limitation. Furthermore, the phase coupling between multiple low-frequency signals is likely to produce a high rate of false positives when CFC is evaluated using bivariate methods. Here, we present a novel method for estimating the statistical dependence between one high-frequency signal and $N$ low-frequency signals, termed multivariate phase-coupling estimation (PCE). Compar... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5521818 Wed, 21 Dec 2011 00:24:55 +0100 5521818 http://www.medworm.com/index.php?rid=5521817&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6106028%26arnumber%3D6104120 (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5521817 Wed, 21 Dec 2011 00:24:54 +0100 5521817 http://www.medworm.com/index.php?rid=5521816&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6106028%26arnumber%3D6106063 (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5521816 Wed, 21 Dec 2011 00:24:54 +0100 5521816 http://www.medworm.com/index.php?rid=5521815&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6106028%26arnumber%3D6106058 (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5521815 Wed, 21 Dec 2011 00:24:54 +0100 5521815 http://www.medworm.com/index.php?rid=5521814&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6106028%26arnumber%3D6106062 (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5521814 Wed, 21 Dec 2011 00:24:54 +0100 5521814 http://www.medworm.com/index.php?rid=5521813&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6106028%26arnumber%3D6106057 (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5521813 Wed, 21 Dec 2011 00:24:54 +0100 5521813 http://www.medworm.com/index.php?rid=5438845&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6082053%26arnumber%3D6082057 (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5438845 Thu, 24 Nov 2011 00:43:18 +0100 5438845 http://www.medworm.com/index.php?rid=5438844&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6082053%26arnumber%3D6082058 (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5438844 Thu, 24 Nov 2011 00:43:18 +0100 5438844 http://www.medworm.com/index.php?rid=5438843&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6082053%26arnumber%3D6017105 In this report, we address the problem of vessels attachments by proposing an automated correction method applied to an initial rough segmentation of the lung nodule. The method is based on a local shape analysis of the initial segmentation making use of 3-D geodesic distance map representations. The correction method has the advantage that it locally refines the nodule segmentation along recognized vessel attachments only, without modifying the nodule boundary elsewhere. The method was tested using a simple initial rough segmentation, obtained by a fixed image thresholding. The validation of the complete segmentation algorithm was carried out on small lung nodules, identified in the ITALUNG screening trial and on small nodules of the lung image database consortium (LIDC) dataset. In fully... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5438843 Thu, 24 Nov 2011 00:43:17 +0100 5438843 http://www.medworm.com/index.php?rid=5438842&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6082053%26arnumber%3D6009176 In this study, we present a multidimensional ICA (MICA) scheme to achieve automatic component clustering. In our MICA framework, stable components are hierarchically grouped into clusters based on higher order statistical dependence—mutual information—among spatial components, instead of the typically used temporal correlation among time courses. The final cluster membership is determined using a statistical hypothesis testing method. Since ICA decomposition takes into account the modulation of the spatial maps, i.e., temporal information, our ICA-based approach incorporates both spatial and temporal information effectively. Our experimental results from both simulated and real fMRI datasets show that the use of spatial dependence leads to physiologically meaningful connectiv... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5438842 Thu, 24 Nov 2011 00:43:17 +0100 5438842 http://www.medworm.com/index.php?rid=5438841&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6082053%26arnumber%3D6003767 Temporal heterogeneity of ventricular repolarization is a key quantity for the development of ventricular reentrant arrhythmia. In this paper, we introduce the ${cal V}$ -index, a novel ECG-based estimator of the standard deviation of ventricular myocytes’ repolarization times $s_vartheta$. Differently from other ECG metrics of repolarization heterogeneity, the ${cal V}$-index was derived from the analysis of a biophysical model of the ECG, where repolarization is described by the dominant T-wave (DTW) paradigm. The model explains the shape of T-waves in each lead as a projection of a main waveform (the DTW) and its derivatives weighted by scalars, the lead factors. A mathematical formula is derived to link the heterogeneity of ventricular repolarization $s_vartheta$ and the ${cal V... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5438841 Thu, 24 Nov 2011 00:43:17 +0100 5438841 http://www.medworm.com/index.php?rid=5438840&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6082053%26arnumber%3D6003765 This paper introduces a model of the atrioventricular node function during atrial fibrillation (AF), and describes the related ECG-based estimation method. The proposed model is defined by parameters that characterize the arrival rate of atrial impulses, the probability of an impulse choosing either one of the two atrioventricular nodal pathways, the refractory periods of these pathways, and the prolongation of the refractory periods. These parameters are estimated from the RR intervals using maximum likelihood estimation, except for the shorter refractory period which is estimated from the RR interval Poincaré plot, and the mean arrival rate of atrial impulses by the AF frequency. Simulations indicated that 200–300 RR intervals are generally needed for the estimates to be ac... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5438840 Thu, 24 Nov 2011 00:43:17 +0100 5438840 http://www.medworm.com/index.php?rid=5438839&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6082053%26arnumber%3D5999711 Classical measurements of myocardium tissue electrical impedance for characterizing the morphology of myocardium cells, as well as cell membranes integrity and intra/extra cellular spaces, are based on the frequency-sweep electrical impedance spectroscopy (EIS) technique. In contrast to the frequency-sweep EIS approach, measuring with broadband signals, i.e., multisine excitations, enables to collect, simultaneously, multiple myocardium tissue impedance data in a short measuring time. However, reducing the measuring time makes the measurements to be prone to the influence of the transients introduced by noise and the dynamic time-varying properties of tissue. This paper presents a novel approach for the impedance-frequency-response estimation based on the local polynomial method (LPM). The... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5438839 Thu, 24 Nov 2011 00:43:17 +0100 5438839 http://www.medworm.com/index.php?rid=5438838&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6082053%26arnumber%3D6032078 In conclusion, the present results indicate that our novel marker design is well suited for MMM with more flexible sensor technologies, such as magnetoresistive sensors. (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5438838 Thu, 24 Nov 2011 00:43:17 +0100 5438838 http://www.medworm.com/index.php?rid=5438837&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6082053%26arnumber%3D5959957 Respiratory sounds are always contaminated by heart sound interference. An essential preprocessing step in some of the heart sound cancellation methods is localizing primary heart sound components. Singular spectrum analysis (SSA), a powerful time series analysis technique, is used in this paper. Despite the frequency overlap of the heart and lung sound components, two different trends in the eigenvalue spectra are recognizable, which leads to find a subspace that contains more information about the underlying heart sound. Artificially mixed and real respiratory signals are used for evaluating the performance of the method. Selecting the appropriate length for the SSA window results in good decomposition quality and low computational cost for the algorithm. The results of the proposed meth... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5438837 Thu, 24 Nov 2011 00:43:17 +0100 5438837 http://www.medworm.com/index.php?rid=5438836&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6082053%26arnumber%3D5959958 This study presents a novel technique using high duty-cycle visual flicker to decrease user's visual discomfort. The proposed design uses LEDs flashing at 13.16 Hz, driven by flickering sequences consisting of repetitive stimulus cycles with a duration T (T = 76 ms). Each stimulus cycle included an ON state with a duration T $_{rm ON}$ and an OFF state with a duration T$_{rm OFF}$ ( T = T $_{rm ON}$ + T $_{rm OFF}$), and the duty cycle, defined as T$_{rm ON}$/ T, varied from 10.5% to 89.5%. This study also includes a questionnaire survey and analyzes the SSVEPs induced by different duty-cycle flickers. An 89.5% duty-cycle flicker, reported as a comfortable flicker, was adopted in a phase-tagged SSVEP system. Six subjects were asked to... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5438836 Thu, 24 Nov 2011 00:43:17 +0100 5438836 http://www.medworm.com/index.php?rid=5438835&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6082053%26arnumber%3D5696743 Computer models of cardiac electrophysiology (EP) can be a very efficient tool to better understand the mechanisms of arrhythmias. Quantitative adjustment of such models to experimental data (personalization) is needed in order to test their realism and predictive power, but it remains challenging at the organ scale. In this paper, we propose a framework for the personalization of a 3-D cardiac EP model, the Mitchell–Schaeffer (MS) model, and evaluate its volumetric predictive power under various pacing scenarios. The personalization was performed on ex vivo large porcine healthy hearts using diffusion tensor MRI (DT-MRI) and optical mapping data. The MS model was simulated on a 3-D mesh incorporating local fiber orientations, built from DT-MRI. The 3-D model parameters were optimiz... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5438835 Thu, 24 Nov 2011 00:43:17 +0100 5438835 http://www.medworm.com/index.php?rid=5438834&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6082053%26arnumber%3D5688444 A device to generate standing or locomotion through chronically placed electrodes has not been fully developed due in part to limitations of clinical experimentation and the high number of muscle activation inputs of the leg. We investigated the feasibility of functional electrical stimulation paradigms that minimize the input dimensions for controlling the limbs by stimulating at nerve fascicles, utilizing a model of the rat hindlimb, which combined previously collected morphological data with muscle physiological parameters presented herein. As validation of the model, we investigated the suitability of a lumped-parameter model for the prediction of muscle activation during dynamic tasks. Using the validated model, we found that the space of forces producible through activation of muscle... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5438834 Thu, 24 Nov 2011 00:43:17 +0100 5438834 http://www.medworm.com/index.php?rid=5438833&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6082053%26arnumber%3D5692821 We describe a finite-element (FE) model for simulating wheel-rolling tissue deformations using a rolling FE model (RFEM). A wheeled probe performing rolling tissue indentation has proven to be a promising approach for compensating for the loss of haptic and tactile feedback experienced during robotic-assisted minimally invasive surgery (H. Liu, D. P. Noonan, B. J. Challacombe, P. Dasgupta, L. D. Seneviratne, and K. Althoefer, “Rolling mechanical imaging for tissue abnormality localization during minimally invasive surgery, ” IEEE Trans. Biomed. Eng., vol. 57, no. 2, pp. 404–414, Feb. 2010; K. Sangpradit, H. Liu, L. Seneviratne, and K. Althoefer, “Tissue identification using inverse finite element analysis of rolling indentation,” in Proc. IEEE Int. Conf. ... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5438833 Thu, 24 Nov 2011 00:43:17 +0100 5438833 http://www.medworm.com/index.php?rid=5438832&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6082053%26arnumber%3D5677451 This study showed that external conductivity and cell radius are important parameters affecting the pore-opening phenomenon. However, if the cell radius is larger than 7 μm in low conductivity medium, the cell dimensions are not so important. (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5438832 Thu, 24 Nov 2011 00:43:17 +0100 5438832 http://www.medworm.com/index.php?rid=5438831&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6082053%26arnumber%3D5657249 Functional magnetic resonance imaging (fMRI) acoustic noise exhibits an almost periodic nature (quasi-periodicity) due to the repetitive nature of currents in the gradient coils. Small changes occur in the waveform in consecutive periods due to the background noise and slow drifts in the electroacoustic transfer functions that map the gradient coil waveforms to the measured acoustic waveforms. The period depends on the number of slices per second, when echo planar imaging (EPI) sequencing is used. Linear predictability of fMRI acoustic noise has a direct effect on the performance of active noise control (ANC) systems targeted to cancel the acoustic noise. It is shown that by incorporating some samples from the previous period, very high linear prediction accuracy can be reached with a very... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5438831 Thu, 24 Nov 2011 00:43:17 +0100 5438831 http://www.medworm.com/index.php?rid=5438830&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6082053%26arnumber%3D6082054 (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5438830 Thu, 24 Nov 2011 00:43:17 +0100 5438830 http://www.medworm.com/index.php?rid=5438829&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6082053%26arnumber%3D6082056 (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5438829 Thu, 24 Nov 2011 00:43:17 +0100 5438829 http://www.medworm.com/index.php?rid=5438828&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6082053%26arnumber%3D6084787 (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5438828 Thu, 24 Nov 2011 00:43:16 +0100 5438828 http://www.medworm.com/index.php?rid=5332823&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6047315%26arnumber%3D6047364 (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5332823 Fri, 21 Oct 2011 03:39:35 +0100 5332823 http://www.medworm.com/index.php?rid=5332822&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6047315%26arnumber%3D6047361 (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5332822 Fri, 21 Oct 2011 03:39:35 +0100 5332822 http://www.medworm.com/index.php?rid=5332821&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6047315%26arnumber%3D6047363 (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5332821 Fri, 21 Oct 2011 03:39:35 +0100 5332821 http://www.medworm.com/index.php?rid=5332820&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6047315%26arnumber%3D6047362 (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5332820 Fri, 21 Oct 2011 03:39:35 +0100 5332820 http://www.medworm.com/index.php?rid=5332819&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6047315%26arnumber%3D6047359 (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5332819 Fri, 21 Oct 2011 03:39:35 +0100 5332819 http://www.medworm.com/index.php?rid=5332818&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6047315%26arnumber%3D6015537 Virtual reality (VR) simulators aim to enhance surgical education by allowing trainees to optimize their skills without patient risk. To achieve this quality, an objective analysis of surgical dexterity is crucial. The application of hidden Markov models (HMMs) has offered important insights in the evaluation of surgical skills (e.g., task decomposition), but there are still issues that need standardization, especially when constructing the hand motion vocabulary. In this paper, we investigate an alternative approach based on multivariate autoregressive (MAR) models. Kinematic signals from orientation sensors attached to the instruments of a VR simulator were used to study the laparoscopic skills of surgical residents. Two different tasks were performed: knot tying and needle driving. A va... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5332818 Fri, 21 Oct 2011 03:39:34 +0100 5332818 http://www.medworm.com/index.php?rid=5332817&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6047315%26arnumber%3D6011673 Electroporation-based applications require the use of specific pulse parameters for a successful outcome. When recommended values of pulse parameters cannot be set, similar outcomes can be obtained by using equivalent pulse parameters. We determined the relations between the amplitude and duration/number of pulses resulting in the same fraction of electroporated cells. Pulse duration was varied from 150 ns to 100 ms, and the number of pulses from 1 to 128. Fura 2-AM was used to determine electroporation of cells to Ca $^{2+}$. With longer pulses or higher number of pulses, lower amplitudes are needed for the same fraction of electroporated cells. The expression derived from the model of electroporation could describe the measured data on the whole interval of pulse durations. In a narrower... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5332817 Fri, 21 Oct 2011 03:39:34 +0100 5332817 http://www.medworm.com/index.php?rid=5332816&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6047315%26arnumber%3D6009174 We have investigated the use of microwave heating and radiometry to safely heat urine inside a pediatric bladder. The medical application for this research is to create a safe and reliable method to detect vesicoureteral reflux, a pediatric disorder, where urine flow is reversed and flows from the bladder back up into the kidney. Using fat and muscle tissue models, we have performed both experimental and numerical simulations of a pediatric bladder model using planar dual concentric conductor microstrip antennas at 915 MHz for microwave heating. A planar elliptical antenna connected to a 500 MHz bandwidth microwave radiometer centered at 3.5 GHz was used for noninvasive temperature measurement inside tissue. Temperatures were measured in the phantom models at points during the experiment w... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5332816 Fri, 21 Oct 2011 03:39:34 +0100 5332816 http://www.medworm.com/index.php?rid=5332815&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6047315%26arnumber%3D6009175 This study challenges the assumption for spatial homogeneity of electric field excitation of miniature catheters and investigated the electric field distribution of miniature catheters in the murine heart, based on cardiac model-driven (geometric, lump component) simulations and noninvasive imaging, at both systolic and diastolic cardiac phases. Results confirm the nonuniform catheter emission field, confined spatially within the LV cavity and myocardium, falling to 10% of its peak value at the ring electrode surface, within 1.1–2.0 mm, given a relative tissue permittivity of 33 615. Additionally, <1% of power leaks were observed into surrounding cavities or organs at end-diastole. Temporally varying parallel conductance effects are also confirmed, bec... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5332815 Fri, 21 Oct 2011 03:39:34 +0100 5332815 http://www.medworm.com/index.php?rid=5332814&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6047315%26arnumber%3D6008631 In this study, the effect of insertion speed on long-term tissue response and insertion mechanics was investigated. A dummy silicon parylene-coated probe was used in this context and implanted in the rat brain at 10 μm/s (n = 6) or 100 μm/s ( n = 6) to a depth of 9 mm. The insertion mechanics were assessed by the dimpling distance, and the force at the point of penetration, at the end of the insertion phase, and after a 3-min rest period in the brain. After 6 weeks, the tissue response was evaluated by estimating the amount of gliosis, inflammation, and neuronal cell loss with immunohistochemistry. No difference in dimpling, penetration force, or the force after a 3-min rest period in the brain was observed. However, the force at the end of ... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5332814 Fri, 21 Oct 2011 03:39:34 +0100 5332814 http://www.medworm.com/index.php?rid=5332813&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6047315%26arnumber%3D6006518 Angle-closure glaucoma is a major blinding eye disease and could be detected by measuring the anterior chamber angle in the human eyes. High-definition OCT (Cirrus HD-OCT) is an emerging noninvasive, high-speed, and high-resolution imaging modality for the anterior segment of the eye. Here, we propose a novel algorithm which automatically detects a new landmark, Schwalbe’s line, and measures the anterior chamber angle in the HD-OCT images. The distortion caused by refraction is corrected by dewarping the HD-OCT images, and three biometric measurements are defined to quantitatively assess the anterior chamber angle. The proposed algorithm was tested on 40 HD-OCT images of the eye and provided accurate measurements in about 1 second. (Source: IEEE Transactions on Biomedical Engineerin... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5332813 Fri, 21 Oct 2011 03:39:34 +0100 5332813 http://www.medworm.com/index.php?rid=5332812&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6047315%26arnumber%3D6006517 Potential harmful effects of ventilation therapy could be reduced by model-based predictions of the effects of ventilator settings to the patient. To obtain optimal predictions, the model has to be individualized based on patients’ data. Given a nonlinear model, the result of parameter identification using iterative numerical methods depends on initial estimates. In this work, a feasible hierarchical identification process is proposed and compared to the commonly implemented direct approach with randomized initial values. The hierarchical approach is exemplarily illustrated by identifying the viscoelastic model (VEM) of respiratory mechanics, whose a priori identifiability was proven. To demonstrate its advantages over the direct approach, two different data sources were employed. F... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5332812 Fri, 21 Oct 2011 03:39:34 +0100 5332812 http://www.medworm.com/index.php?rid=5332811&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6047315%26arnumber%3D5993522 Lung protective ventilation is intended to minimize the risk of ventilator induced lung injury and currently aimed at preservation of spontaneous breathing during mechanical ventilation. High-frequency oscillatory ventilation (HFOV) is a lung protective ventilation strategy. Commonly used high-frequency oscillatory (HFO) ventilators, SensorMedics 3100, were not designed to tolerate spontaneous breathing. Respiratory efforts in large pediatric and adult patients impose a high workload to the patient and may cause pressure swings that impede ventilator function. A Demand Flow System (DFS) was designed to facilitate spontaneous breathing during HFOV. Using a linear quadratic Gaussian state feedback controller, the DFS alters the inflow of gas into the ventilator circuit, so that it instantane... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5332811 Fri, 21 Oct 2011 03:39:34 +0100 5332811 http://www.medworm.com/index.php?rid=5332810&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6047315%26arnumber%3D5995155 This study has shown that the condition number of the sensitivity matrix obtained from the multimodal tomography with 16-electrode and 16-coil is much lower than the condition number produced in the conventional 16-channel EIT and MIT systems, and thus, produced promising results in terms of image stability. An improvement of about 20% in image resolution can be achieved considering feasible signal-to-noise ratio levels. (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5332810 Fri, 21 Oct 2011 03:39:34 +0100 5332810 http://www.medworm.com/index.php?rid=5332809&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6047315%26arnumber%3D5995157 We investigated the association between individual differences in cognitive performance in old age and the approximate entropy (ApEn) measured from functional magnetic resonance imaging (fMRI) data acquired from 40 participants of the Aberdeen Birth Cohort 1936 (ABC1936), while undergoing a visual information processing task: inspection time (IT). Participants took a version of the Moray House Test (MHT) No. 12 at age 11, a valid measure of childhood intelligence. The same individuals completed a test of non-verbal reasoning (Raven's Standard Progressive Matrices [RPM]) aged about 68 years. The IT, MHT and RPM scores were used as indicators of cognitive performance. Our results show that higher regional signal entropy is associated with better cognitive performance. This finding was... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5332809 Fri, 21 Oct 2011 03:39:34 +0100 5332809 http://www.medworm.com/index.php?rid=5332808&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6047315%26arnumber%3D5995156 A miniaturized, hermetically encased, wirelessly operated retinal prosthesis has been developed for preclinical studies in the Yucatan minipig, and includes several design improvements over our previously reported device. The prosthesis attaches conformally to the outside of the eye and electrically drives a microfabricated thin-film polyimide array of sputtered iridium oxide film electrodes. This array is implanted into the subretinal space using a customized ab externo surgical technique. The implanted device includes a hermetic titanium case containing a 15-channel stimulator chip and discrete circuit components. Feedthroughs in the case connect the stimulator chip to secondary power and data receiving coils on the eye and to the electrode array under the retina. Long-term in vitro puls... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5332808 Fri, 21 Oct 2011 03:39:34 +0100 5332808 http://www.medworm.com/index.php?rid=5332807&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6047315%26arnumber%3D5993521 We present a novel approach, integrating principal component analysis (PCA) and supervised affinity propagation clustering (SAPC). In this method, fMRI data are initially processed by PCA to obtain a preliminary image of brain activation. SAPC is then used to detect different brain functional activation patterns. We used a supervised Silhouette index to optimize clustering quality and automatically search for the optimal parameter $p$ in SAPC, so that the basic affinity propagation clustering is improved by applying SAPC. Four simulation studies and tests with three in vivo fMRI datasets containing data from both block-design and event-related experiments revealed that functional brain activation was effectively detected and different response patterns were distinguished using our integrat... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5332807 Fri, 21 Oct 2011 03:39:34 +0100 5332807 http://www.medworm.com/index.php?rid=5332806&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6047315%26arnumber%3D5989848 The maximal upstroke of transmembrane voltage (dV $_m$/dt $_{rm max}$) has been used as an indirect measure of sodium current I$_{rm Na}$ upon activation in cardiac myocytes. However, sodium influx generates not only the upstroke of V$_m$, but also the downstroke of the extracellular potentials V$_e$ including epicardial surface potentials V $_{rm es}$. The purpose of this study was to evaluate the magnitude of the maximal downstroke of V$_{rm es}$ ($vert $dV $_{rm es}$/dt $_{rm min}$$vert $ ) as a global index of electrical activation, based on the relationship of dV $_m$/dt $_{rm max}$ to I $_{rm Na}$. To fulfill this purpose, we examined $vert $dV $_{rm es}$/dt $_{rm min}$$vert $ experimentally using isolated perfused mouse hearts and computationally using a 3-D cardiac tissue bidom- - ... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5332806 Fri, 21 Oct 2011 03:39:34 +0100 5332806 http://www.medworm.com/index.php?rid=5332805&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6047315%26arnumber%3D5985487 Pulsed arterial spin labeling (PASL) techniques potentially allow the absolute, noninvasive quantification of brain perfusion using MRI. This can be achieved by fitting a kinetic model to the data acquired at a number of sampling times. However, the intrinsically low signal-to-noise ratio of PASL measurements usually requires substantial signal averaging, which may result in undesirably long scanning times. A judicious choice of the sampling points is, therefore, crucial in order to minimize scanning time, while optimizing estimation accuracy. On the other hand, a priori information regarding the model parameters may improve estimation performance. Here, we propose a Bayesian framework to determine an optimal sampling strategy and estimation method for the measurement of brain perfusion an... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5332805 Fri, 21 Oct 2011 03:39:34 +0100 5332805 http://www.medworm.com/index.php?rid=5332804&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6047315%26arnumber%3D5983411 The early stages of the drug development process are often characterized by a limited number of subjects participating the study and a limited number of measurements per individual that can be collected, mainly due to technical, ethical, and cost reasons. The so-called dose escalation studies, performed during phase I, usually involve about 40 subjects or less, and feature observations at no more than three (rarely four or five) dose levels-per-subject. Depending on the complexity of the underlying pharmacokinetics, simple linear models or nonlinear ones (e.g., power, $E_{rm max}$ models) may be appropriate to describe the relationship between the metrics of systemic exposure to the drug ( $C_{rm max}$, $AUC$ ) and the administered dose. However, in such data-poor scenarios, formulating mo... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5332804 Fri, 21 Oct 2011 03:39:33 +0100 5332804 http://www.medworm.com/index.php?rid=5332803&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6047315%26arnumber%3D5985489 This study provides experimental evidence that organ geometry and boundary conditions surrounding the organ are important factors influencing target motion. In future work, the technique presented in this paper could be used for preoperative planning of minimally invasive surgical interventions. (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5332803 Fri, 21 Oct 2011 03:39:33 +0100 5332803 http://www.medworm.com/index.php?rid=5332802&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6047315%26arnumber%3D5975205 Conclusion: rigid tracking appears to be promising. Three tracking slices yield significantly high registration speed with an affordable error. (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5332802 Fri, 21 Oct 2011 03:39:33 +0100 5332802 http://www.medworm.com/index.php?rid=5332801&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6047315%26arnumber%3D6017106 Intramural measurements of V$_m$ and Ca$_i^{2+}$ are important in the studies of cardiac arrhythmias and defibrillation. We developed a new design of an “optrode” (bundle of optical fibers) for use in intramural cardiac mapping. The optrodes are made from seven optical fibers with the fiber ends polished at 45$^{circ}$ angle and coated with mirror surfaces. The optrodes are enclosed in smooth epoxy resin cast, which protects mirror surfaces from damage and ensures constant optrode diameter along its length. The optrodes are strong enough to be easily inserted into heart muscle, can be reused multiple times, and they may reduce artifacts in the measurements of the effects of defibrillation shocks on V$_m$. (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5332801 Fri, 21 Oct 2011 03:39:33 +0100 5332801 http://www.medworm.com/index.php?rid=5332800&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6047315%26arnumber%3D5976430 We present a theoretical analysis that explains how the use of imaginary part can remove this spurious coherence. We then present results from both computer simulations and experiments using resting-state MEG data which demonstrate the validity of our analysis. (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5332800 Fri, 21 Oct 2011 03:39:33 +0100 5332800 http://www.medworm.com/index.php?rid=5332799&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6047315%26arnumber%3D5976431 Modern automobiles include an increasing number of assistance systems to increase the driver’s safety. This feasibility study investigated unobtrusive capacitive ECG measurements in an automotive environment. Electrodes integrated into the driving seat allowed to measure a reliable ECG in 86% of the drivers; when only (light) cotton clothing was worn by the drivers, this value increased to 95%. Results show that an array of sensors is needed that can adapt to the different drivers and sitting positions. Measurements while driving show that traveling on the highway does not distort the signal any more than with the car engine turned OFF, whereas driving in city traffic results in a lowered detection rate due to the driver’s heavier movements. To enable robust and... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5332799 Fri, 21 Oct 2011 03:39:33 +0100 5332799 http://www.medworm.com/index.php?rid=5332798&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6047315%26arnumber%3D5975204 In this paper, we present an ultrasonically powered implantable micro-oxygen generator (IMOG) that is capable of in situ tumor oxygenation through water electrolysis. Such active mode of oxygen generation is not affected by increased interstitial pressure or abnormal blood vessels that typically limit the systemic delivery of oxygen to hypoxic regions of solid tumors. Wireless ultrasonic powering (2.15 MHz) was employed to increase the penetration depth and eliminate the directional sensitivity associated with magnetic methods. In addition, ultrasonic powering allowed for further reduction in the total size of the implant by eliminating the need for a large area inductor. IMOG has an overall dimension of 1.2 mm × 1.3 mm × 8 mm, small enough to be implanted using... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5332798 Fri, 21 Oct 2011 03:39:33 +0100 5332798 http://www.medworm.com/index.php?rid=5332797&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6047315%26arnumber%3D5970099 This paper investigates different approaches for supplying power to implantable hearing systems via energy harvesting. Because of the specific nature of the problem, only energy harvesting in the region of the human head is considered. Upper bounds as well as more conservative estimations for harvesting mechanical, thermal, and electromagnetic energy are presented and discussed. (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5332797 Fri, 21 Oct 2011 03:39:33 +0100 5332797 http://www.medworm.com/index.php?rid=5332796&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6047315%26arnumber%3D5959956 Multivariate Granger causality is a well-established approach for inferring information flow in complex systems, and it is being increasingly applied to map brain connectivity. Traditional Granger causality is based on vector autoregressive (AR) or mixed autoregressive moving average (ARMA) model, which are potentially affected by errors in parameter estimation and may be contaminated by zero-lag correlation, notably when modeling neuroimaging data. To overcome this issue, we present here an extended canonical correlation approach to measure multivariate Granger causal interactions among time series. The procedure includes a reduced rank step for calculating canonical correlation analysis (CCA), and extends the definition of causality including instantaneous effects, thus avoiding the pote... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5332796 Fri, 21 Oct 2011 03:39:33 +0100 5332796 http://www.medworm.com/index.php?rid=5332795&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6047315%26arnumber%3D5934367 Respiratory sound (RS) signals carry significant information about the underlying functioning of the pulmonary system by the presence of adventitious sounds (ASs). Although many studies have addressed the problem of pathological RS classification, only a limited number of scientific works have focused on the analysis of the evolution of symptom-related signal components in joint time–frequency (TF) plane. This paper proposes a new signal identification and extraction method for various ASs based on instantaneous frequency (IF) analysis. The presented TF decomposition method produces a noise-resistant high definition TF representation of RS signals as compared to the conventional linear TF analysis methods, yet preserving the low computational complexity as compared to those quadrati... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5332795 Fri, 21 Oct 2011 03:39:33 +0100 5332795 http://www.medworm.com/index.php?rid=5332794&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6047315%26arnumber%3D5930345 Repetitive flicker stimulation (photic driving) offers the possibility to study the properties and coupling characteristics of stimulation-sensitive neuronal oscillators by means of the MEG/EEG analysis. With flicker frequencies in the region of the individual alpha band frequency, the dynamics of the entrainment process of the alpha oscillation, as well as the dynamics of the accompanying gamma oscillations and the coupling between the oscillations, are investigated by means of an appropriate combination of time-variant analysis methods. The Hilbert and the Gabor transformation reveal time-variant properties (frequency entrainment, phase locking, and n:m synchronization) of the entrainment process in the whole frequency range. Additionally, time-variant partial directed coherence is appli... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5332794 Fri, 21 Oct 2011 03:39:33 +0100 5332794 http://www.medworm.com/index.php?rid=5332793&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6047315%26arnumber%3D5740955 This study proposes an automatic pronunciation error identification system that uses a novel dependence network (DN) approach. In order to derive a subject's articulatory information, a photo naming task is performed to obtain the subject's speech patterns. Based on clinical knowledge about speech evaluation, a DN scheme was used to model the relationships of a test word, a subject, a speech pattern, and an articulation error pattern. To integrate DN into automatic speech recognition (ASR), a pronunciation confusion network is proposed to model the probability of DN and is then used to guide the search space of the ASR. Further, to increase the accuracy of the ASR, an appropriate threshold based on a histogram of pronunciation errors is selected in order to disregard rare pro... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5332793 Fri, 21 Oct 2011 03:39:33 +0100 5332793 http://www.medworm.com/index.php?rid=5332792&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6047315%26arnumber%3D5740584 This paper reports the development, evaluation, and first clinical trials of the access to the prostate tissue (APT) II system—a scanner independent system for magnetic resonance imaging (MRI)-guided transrectal prostate interventions. The system utilizes novel manipulator mechanics employing a steerable needle channel and a novel six degree-of-freedom hybrid tracking method, comprising passive fiducial tracking for initial registration and subsequent incremental motion measurements. Targeting accuracy of the system in prostate phantom experiments and two clinical human-subject procedures is shown to compare favorably with existing systems using passive and active tracking methods. The portable design of the APT II system, using only standard MRI image sequences and minimal custom s... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5332792 Fri, 21 Oct 2011 03:39:33 +0100 5332792 http://www.medworm.com/index.php?rid=5332791&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6047315%26arnumber%3D5635325 Joint stiffness, the dynamic relationship between the angular position of a joint and the torque acting about it, describes the dynamic, mechanical behavior of a joint during posture and movement. Joint stiffness arises from both intrinsic and reflex mechanisms, but the torques due to these mechanisms cannot be measured separately experimentally, since they appear and change together. Therefore, the direct estimation of the intrinsic and reflex stiffnesses is difficult. In this paper, we present a new, two-step procedure to estimate the intrinsic and reflex components of ankle stiffness. In the first step, a discrete-time, subspace-based method is used to estimate a state-space model for overall stiffness from the measured overall torque and then predict the intrinsic and reflex torques. I... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5332791 Fri, 21 Oct 2011 03:39:32 +0100 5332791 http://www.medworm.com/index.php?rid=5332790&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6047315%26arnumber%3D6047358 (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5332790 Fri, 21 Oct 2011 03:39:32 +0100 5332790 http://www.medworm.com/index.php?rid=5332789&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6047315%26arnumber%3D6047360 (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5332789 Fri, 21 Oct 2011 03:39:32 +0100 5332789 http://www.medworm.com/index.php?rid=5332788&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6047315%26arnumber%3D6047357 (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5332788 Fri, 21 Oct 2011 03:39:32 +0100 5332788 http://www.medworm.com/index.php?rid=5247707&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6021989%26arnumber%3D6021996 (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5247707 Sat, 24 Sep 2011 01:11:59 +0100 5247707 http://www.medworm.com/index.php?rid=5247706&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6021989%26arnumber%3D6021993 (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5247706 Sat, 24 Sep 2011 01:11:58 +0100 5247706 http://www.medworm.com/index.php?rid=5247705&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6021989%26arnumber%3D6021995 (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5247705 Sat, 24 Sep 2011 01:11:58 +0100 5247705 http://www.medworm.com/index.php?rid=5247704&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6021989%26arnumber%3D6021994 (Source: IEEE Transactions on Biomedical Engineering) IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5247704 Sat, 24 Sep 2011 01:11:58 +0100 5247704 http://www.medworm.com/index.php?rid=5247703&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6021989%26arnumber%3D5963707 Surgical navigation systems are used widely among all fields of modern medicine, including, but not limited to ENT- and maxillofacial surgery. As a fundamental prerequisite for image-guided surgery, intraoperative registration, which maps image to patient coordinates, has been subject to many studies and developments. While registration methods have evolved from invasive procedures like fixed stereotactic frames and implanted fiducial markers toward surface-based registration and noninvasive markers fixed to the patient’s skin, even the most sophisticated registration techniques produce an imperfect result. Due to errors introduced during the registration process, the projection of navigated instruments into image data deviates up to several millimeter from the actual position, depe... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5247703 Sat, 24 Sep 2011 01:11:58 +0100 5247703 http://www.medworm.com/index.php?rid=5247702&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6021989%26arnumber%3D5962352 The identification and characterization of pathological tremor are necessary for the development of techniques for tremor suppression, for example, based on functional electrical stimulation. For this purpose, the amplitude and phase characteristics of the tremor signal should be estimated by effective detection techniques, either from the kinematics or from muscle recordings. This paper presents an approach for the estimation of the characteristics of pathological tremor from the surface electromyogram (EMG) signal based on the iterated Hilbert transform (IHT). It is shown that the IHT allows an asymptotically exact modeling of the tremor and the voluntary activity components in the surface EMG, and an effective demodulation of the pathological tremor parameters. The method was tested on ... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5247702 Sat, 24 Sep 2011 01:11:58 +0100 5247702 http://www.medworm.com/index.php?rid=5247701&cid=s_37223_169_f&fid=37223&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Fisnumber%3D6021989%26arnumber%3D5958581 Access to the cochlea requires drilling in close proximity to bone-embedded nerves, blood vessels, and other structures, the violation of which can result in complications for the patient. It has recently been shown that microstereotactic frames can enable an image-guided percutaneous approach, removing reliance on human experience and hand–eye coordination, and reducing trauma. However, constructing current microstereotactic frames disrupts the clinical workflow, requiring multiday intrasurgical manufacturing delays, or an on-call machine shop in or near the hospital. In this paper, we describe a new kind of microsterotactic frame that obviates these delay and infrastructure issues by being repositionable. Inspired by the prior success of bone-attached parallel robots in knee and s... IEEE Transactions on Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5247701 Sat, 24 Sep 2011 01:11:58 +0100 5247701