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

Social Learning With Bayesian Agents and Random Decision Making
In this paper, we study the effect of randomness in the decision making of agents on social learning. In the addressed system, the agents make decisions sequentially about the true state of nature. Each agent observes a signal produced according to one of two hypotheses, which represents the state of nature. The signals of all the agents are generated independently from the same state. The agents also know the decisions of all the previous agents in the network. The randomness in this paper is modeled by a policy that amounts to random mapping of the beliefs of the agents to the action space. We propose that the agents lea...
Source: IEEE Transactions on Signal Processing - May 22, 2015 Category: Biomedical Engineering Source Type: research

Subspace Leakage Analysis and Improved DOA Estimation With Small Sample Size
Classical methods of DOA estimation such as the MUSIC algorithm are based on estimating the signal and noise subspaces from the sample covariance matrix. For a small number of samples, such methods are exposed to performance breakdown, as the sample covariance matrix can largely deviate from the true covariance matrix. In this paper, the problem of DOA estimation performance breakdown is investigated. We consider the structure of the sample covariance matrix and the dynamics of the root-MUSIC algorithm. The performance breakdown in the threshold region is associated with the subspace leakage where some portion of the true ...
Source: IEEE Transactions on Signal Processing - May 22, 2015 Category: Biomedical Engineering Source Type: research

An Efficient Approach to Graphical Modeling of Time Series
A method for selecting a graphical model for $p$-vector-valued stationary Gaussian time series was recently proposed by Matsuda and uses the Kullback–Leibler divergence measure to define a test statistic. This statistic was used in a backward selection procedure, but the algorithm is prohibitively expensive for large $p$. A high degree of sparsity is not assumed. We show that reformulation in terms of a multiple hypothesis test reduces computation time by $O(p^2)$ and simulations support the assertion that power levels are attained at least as good as those achieved by Matsuda’s much slower approach. Moreover...
Source: IEEE Transactions on Signal Processing - May 22, 2015 Category: Biomedical Engineering Source Type: research

Sparse Inverse Covariance Estimation
Recently, there has been focus on penalized log-likelihood covariance estimation for sparse inverse covariance (precision) matrices. The penalty is responsible for inducing sparsity, and a very common choice is the convex $l_{1}$ norm. However, the best estimator performance is not always achieved with this penalty. The most natural sparsity promoting “norm” is the nonconvex $l_{0}$ penalty but its lack of convexity has deterred its use in sparse maximum likelihood estimation. In this paper, we consider nonconvex $l_{0}$ penalized log-likelihood inverse covariance estimation and present a novel cyclic descent...
Source: IEEE Transactions on Signal Processing - May 22, 2015 Category: Biomedical Engineering Source Type: research

Estimation of Time-Limited Channel Spectra From Nonuniform Samples
This paper deals with the estimation of a time-invariant channel spectrum from its own nonuniform samples, assuming there is a bound on the channel’s delay spread. Except for this last assumption, this is the basic estimation problem in systems providing channel spectral samples. However, as shown in the paper, the delay spread bound leads us to view the spectrum as a band-limited signal, rather than the Fourier transform of a tapped delay line (TDL). Using this alternative model, a linear estimator is presented that approximately minimizes the expected root-mean-square (RMS) error for a deterministic channel. Its m...
Source: IEEE Transactions on Signal Processing - May 22, 2015 Category: Biomedical Engineering Source Type: research

IEEE Transactions on Biomedical Engineering information for authors
These instructions give guidelines for preparing papers for this publication. Presents information for authors publishing in this journal. (Source: IEEE Transactions on Biomedical Engineering)
Source: IEEE Transactions on Biomedical Engineering - May 22, 2015 Category: Biomedical Engineering Source Type: research

IEEE Transactions on Biomedical Engineering Handling Editors
Presents a listing of IEEE Transactions on Biomedical Engineering handling editors. (Source: IEEE Transactions on Biomedical Engineering)
Source: IEEE Transactions on Biomedical Engineering - May 22, 2015 Category: Biomedical Engineering Source Type: research

32-Channel System to Measure the Electrophysiological Properties of Bioengineered Cardiac Muscle
This study allows us to monitor such properties and assess the necessary changes that will improve construct development and function. (Source: IEEE Transactions on Biomedical Engineering)
Source: IEEE Transactions on Biomedical Engineering - May 22, 2015 Category: Biomedical Engineering Source Type: research

Functional Brain Network Classification With Compact Representation of SICE Matrices
Recently, a sparse inverse covariance estimation (SICE) technique has been employed to model functional brain connectivity. The inverse covariance matrix (SICE matrix in short) estimated for each subject is used as a representation of brain connectivity to discriminate Alzheimers disease from normal controls. However, we observed that direct use of the SICE matrix does not necessarily give satisfying discrimination, due to its high dimensionality and the scarcity of training subjects. Looking into this problem, we argue that the intrinsic dimensionality of these SICE matrices shall be much lower, considering 1) an SICE mat...
Source: IEEE Transactions on Biomedical Engineering - May 22, 2015 Category: Biomedical Engineering Source Type: research

Robustness Assessment of 1-D Electron Paramagnetic Resonance for Improved Magnetic Nanoparticle Reconstructions
Electron paramagnetic resonance (EPR) is a sensitive measurement technique which can be used to recover the 1-D spatial distribution of magnetic nanoparticles (MNP) noninvasively. This can be achieved by solving an inverse problem that requires a numerical model for interpreting the EPR measurement data. This paper assesses the robustness of this technique by including different types of errors such as setup errors, measurement errors, and sample positioning errors in the numerical model. The impact of each error is estimated for different spatial MNP distributions. Additionally, our error models are validated by comparing...
Source: IEEE Transactions on Biomedical Engineering - May 22, 2015 Category: Biomedical Engineering Source Type: research

Direct Gaze Estimation Based on Nonlinearity of EOG
Electrooculography (EOG) is one of the measures used to estimate the direction of a person's gaze; however, conventional EOG techniques suffer from a drift issue which makes it difficult to extract an accurate absolute eye angle. The technique proposed here is based on the nonlinearity of the EOG and offers a practical solution to this problem. It estimates the absolute eye angles before and after a saccade, which cancels the offset due to the drift. Additionally, it does not require any effort from the user or any target, but instead uses only the difference of the EOGs. Experiments with five subjects confirm that ...
Source: IEEE Transactions on Biomedical Engineering - May 22, 2015 Category: Biomedical Engineering Source Type: research

Assessment of Cytoplasm Conductivity by Nanosecond Pulsed Electric Fields
The aim of this paper is to propose a new method for the better assessment of cytoplasm conductivity, which is critical to the development of electroporation protocols as well as insight into fundamental mechanisms underlying electroporation. For this goal, we propose to use nanosecond electrical pulses to bypass the complication of membrane polarization and a single cell to avoid the complication of the application of the “mixing formulas.” Further, by suspending the cell in a low-conductivity medium, it is possible to force most of the sensing current through the cytoplasm for a more direct assessment of it...
Source: IEEE Transactions on Biomedical Engineering - May 22, 2015 Category: Biomedical Engineering Source Type: research

Computerized System for Quantitative Assessment of Atherosclerotic Plaques in the Femoral and Iliac Arteries Visualized by Multislice Computed Tomography
Conclusion: The developed system is likely to be valuable tool for supporting the quantitative evaluation of atherosclerotic changes in arteries. Significance: In its present form the system can be used for planning surgical treatment and/or predicting the course of the atherosclerotic alterations. (Source: IEEE Transactions on Biomedical Engineering)
Source: IEEE Transactions on Biomedical Engineering - May 22, 2015 Category: Biomedical Engineering Source Type: research

Accuracy of Femur Angles Estimated by IMUs During Clinical Procedures Used to Diagnose Femoroacetabular Impingement
We present a novel method for quantifying femoral orientation angles using a thigh-mounted inertial measurement unit (IMU). The IMU-derived femoral orientation angles reproduce gold-standard motion capture angles to within mean (standard deviation) differences of 0.1 (1.1) degrees on cadaveric specimens during clinical procedures used for the diagnosis of Femoroacetabular Impingement (FAI). The method, which assumes a stationary pelvis, is easy to use, inexpensive, and provides femur motion trajectory data in addition to range of motion measures. These advantages may accelerate the adoption of this technology to inform FAI...
Source: IEEE Transactions on Biomedical Engineering - May 22, 2015 Category: Biomedical Engineering Source Type: research

A Device for Human Ultrasonic Echolocation
Conclusion: This suggests that the device can be used effectively to examine the environment and that the human auditory system can rapidly adapt to these artificial echolocation cues. Significance: Interpreting and interacting with the external world constitutes a major challenge for persons who are blind or visually impaired. This device has the potential to aid blind people in interacting with their environment. (Source: IEEE Transactions on Biomedical Engineering)
Source: IEEE Transactions on Biomedical Engineering - May 22, 2015 Category: Biomedical Engineering Source Type: research

Analysis of Transcranial Magnetic Stimulation Based on the Surface Integral Equation Formulation
Conclusion: The future work should be related to the development of a more detailed geometrical model of the human brain that will take into account complex cortical columnar structures, as well as some additional brain tissues. Significance: To the best of authors knowledge, similar approach in modeling TMS has not been previously reported, albeit integral equation methods are seeing a revival in computational electromagnetics community. (Source: IEEE Transactions on Biomedical Engineering)
Source: IEEE Transactions on Biomedical Engineering - May 22, 2015 Category: Biomedical Engineering Source Type: research

Sequential Hierarchical Agglomerative Clustering of White Matter Fiber Pathways
Conclusion: Sequential HAC is a fast method that benefits from having a predefined number of clusters, and rapidly assigns labels to incoming data with high accuracy. It can be thought of as a mechanism that does clustering, while simultaneously accepting newly computed fibers; thereby, alleviating the burden of computing the distances between every pair of fibers in a tractogram. Significance: Sequential HAC is a practical tool that can interactively cluster fiber pathways and can be integrated into fiber tracking, which will be very useful for clinical researchers and neuroanatomists. (Source: IEEE Transactions on Biomedical Engineering)
Source: IEEE Transactions on Biomedical Engineering - May 22, 2015 Category: Biomedical Engineering Source Type: research

IEEE Transactions on Biomedical Engineering publication information
Provides a listing of the editors, board members, and current staff for this issue of the publication. (Source: IEEE Transactions on Biomedical Engineering)
Source: IEEE Transactions on Biomedical Engineering - May 22, 2015 Category: Biomedical Engineering Source Type: research

Table of Contents
Presents the table of contents for this issue of the publication. (Source: IEEE Transactions on Biomedical Engineering)
Source: IEEE Transactions on Biomedical Engineering - May 22, 2015 Category: Biomedical Engineering Source Type: research

Development and performance analysis of Si-CaP/fine particulate bone powder combined grafts for bone regeneration
Conclusion: Si-CaP/FPBP combined grafts was found to be superior to any of the two components individually. (Source: BioMedical Engineering OnLine)
Source: BioMedical Engineering OnLine - May 22, 2015 Category: Biomedical Engineering Authors: Chengli SunYe TianWenxiao XuChanglong ZhouHuanxin XieXintao Wang Source Type: research

Pathological aspects of bioresorbable stent implantation.
This article will review the pathological aspects of BRS implantation with a focus on acute and chronic vascular reactions derived from preclinical animal studies, including insights from in vivo imaging. Finally, potential future directions of this novel therapeutic approach will be discussed. PMID: 25983157 [PubMed - in process] (Source: EuroIntervention)
Source: EuroIntervention - May 21, 2015 Category: Cardiovascular & Thoracic Surgery Tags: EuroIntervention Source Type: research

Fabrication and initial testing of the μDBS: a novel Deep Brain Stimulation electrode with thousands of individually controllable contacts.
Abstract High frequency electrical stimulation of deep brain structures such as the subthalamic nucleus in Parkinson's disease or thalamus for essential tremor is used clinically to reduce symptom severity. Deep brain stimulation activates neurons in specific brain structures and connection pathways, overriding aberrant neural activity associated with symptoms. While optimal deep brain stimulation might activate a particular neural structure precisely, existing deep brain stimulation can only generate roughly-spherical regions of activation that do not overlap with any target anatomy. Additionally, side effects lin...
Source: Biomedical Microdevices - May 21, 2015 Category: Biomedical Engineering Authors: Willsie A, Dorval A Tags: Biomed Microdevices Source Type: research

pH-triggered drug release from biodegradable microwells for oral drug delivery.
Abstract Microwells fabricated from poly-L-lactic acid (PLLA) were evaluated for their application as an oral drug delivery system using the amorphous sodium salt of furosemide (ASSF) as a model drug. Hot embossing of PLLA resulted in fabrication of microwells with an inner diameter of 240 μm and a height of 100 μm. The microwells were filled with ASSF using a modified screen printing technique, followed by coating of the microwell cavities with a gastro-resistant lid of Eudragit® L100. The release behavior of ASSF from the coated microwells was investigated using a μ-Diss profiler and a UV imaging system, an...
Source: Biomedical Microdevices - May 21, 2015 Category: Biomedical Engineering Authors: Nielsen LH, Nagstrup J, Gordon S, Keller SS, Østergaard J, Rades T, Müllertz A, Boisen A Tags: Biomed Microdevices Source Type: research

A comparative study of mechanical strain, icariin and combination stimulations on improving osteoinductive potential via NF-kappaB activation in osteoblast-like cells
Background: The combination of drugs and exercise was the effective treatment in bone injure and rebuilding in clinic. As mechanical strain has potential in inducing the differentiation of osteoblasts in our previous study, the further research to investigate the combination of mechanical strain and icariin stimulation on inducing osteoblast proliferation, differentiation and the possible mechanism in MC3T3-E1 cell line. Methods: A whole cell enzyme-linked immunosorbent assay that detects the bromodeoxyuridine incorporation during DNA synthesis was applied to evaluate the proliferation. The mRNA expression of alkaline phos...
Source: BioMedical Engineering OnLine - May 21, 2015 Category: Biomedical Engineering Authors: Qiang-Song WangXin-Chang ZhangRui-Xin LiJing-Gong SunWei-Hua SuYong GuoHao LiXi-Zheng Zhang Source Type: research

Simulation of the mechanical interlocking capacity of a rough bone implant surface during healing
Conclusion: Finite element analysis is a promising method that might be used prior to an in vivo study to compare the load bearing capacity of the bone-to-implant interface of two surface topographies at longer healing times. (Source: BioMedical Engineering OnLine)
Source: BioMedical Engineering OnLine - May 21, 2015 Category: Biomedical Engineering Authors: Anders HalldinMats AnderMagnus JacobssonStig Hansson Source Type: research

On growth measurements of abdominal aortic aneurysms using maximally inscribed spheres
An abdominal aortic aneurysm (AAA) is the localized enlargement of the abdominal aorta that affects a large part of the elderly population; and the more it dilates, the more it will become prone to rupture that is associated with a high mortality rate. Current treatments involve surgical, and either open or endovascular repair. Unfortunately, the risk of these approaches is also high. Therefore, there is an imperative need to decide whether or not an AAA patient needs a medical intervention. Nonetheless, there is no solid argument regarding the appropriate time for an AAA patient to undergo surgery [1–3]. (Source: Medica...
Source: Medical Engineering and Physics - May 21, 2015 Category: Biomedical Engineering Authors: H. Gharahi, B.A. Zambrano, C. Lim, J. Choi, W. Lee, S. Baek Source Type: research

Evaluating endoglucanase Cel7B‐lignin interaction mechanisms and kinetics using quartz crystal microgravimetry
This article is protected by copyright. All rights reserved (Source: Biotechnology and Bioengineering)
Source: Biotechnology and Bioengineering - May 20, 2015 Category: Biomedical Science Authors: Katherine A. Pfeiffer, Hagit Sorek, Christine Roche, Kathryn Strobel, Harvey W. Blanch, Douglas S. Clark Tags: Article Source Type: research

A novel method for discrimination between innocent and pathological heart murmurs
Heart sound auscultation is a powerful technique for screening patients with heart diseases for cardiac examinations. It is often based on the subjective judgments of the temporal and spectral characteristics of the heart sounds and murmurs. Previous studies showed that the joint time-frequency contents of heart murmurs convey diagnostic information about mechanical activities of heart [1–3]. However, physiological restrictions of human auditory system (i.e. masking effect) along with the spectral properties of the cardiac sounds and murmurs (concentrated down to the human auditory threshold), make the subjective assessm...
Source: Medical Engineering and Physics - May 20, 2015 Category: Biomedical Engineering Authors: Arash Gharehbaghi, Magnus Borga, Birgitta Janerot Sjöberg, Per Ask Source Type: research

Swallowing accelerometry signal feature variations with sensor displacement
Deglutition or swallowing is the well-defined, complex neuromuscular process for transporting food or liquid from the mouth to the stomach [1,2]. Patients with a range of different neurological disorders such as stroke, cerebral palsy and Parkinson’s disease are at high risk of developing swallowing difficulties (dysphagia), where the swallow departs from the well-coordinated typical process [1]. Individuals with dysphagia are susceptible to aspiration, which is defined as the entry of foreign material into the airway below the true vocal folds [2]. (Source: Medical Engineering and Physics)
Source: Medical Engineering and Physics - May 20, 2015 Category: Biomedical Engineering Authors: Khondaker A. Mamun, Catriona M. Steele, Tom Chau Source Type: research

A Novel Micro-cantilever Based Angular Speed Sensor Controlled Piezoelectrically and Tuned by Electrostatic Actuators
Abstract In this paper a novel sensor is proposed to measure rotational shafts speed. The sensor is composed of a micro-cantilever, with a piezoelectric actuator layer on the upper surface and a sensor layer on the lower surface. The sensor is attached to the shaft while the deflection of the micro-cantilever, due to centrifugal force of the rotating shaft, is actively controlled. Therefore the sensor deflection is suppressed and the controller output or the piezoelectric actuating voltage is employed to measure the angular speed of the shaft (Force balance technique). The micro-cantilever is symmetrically locate...
Source: Sensing and Imaging - May 19, 2015 Category: Biomedical Engineering Source Type: research

$l_{0}$ Sparse Inverse Covariance Estimation
Recently, there has been focus on penalized log-likelihood covariance estimation for sparse inverse covariance (precision) matrices. The penalty is responsible for inducing sparsity, and a very common choice is the convex $l_{1}$ norm. However, the best estimator performance is not always achieved with this penalty. The most natural sparsity promoting “norm” is the nonconvex $l_{0}$ penalty but its lack of convexity has deterred its use in sparse maximum likelihood estimation. In this paper, we consider nonconvex $l_{0}$ penalized log-likelihood inverse covariance estimation and present a novel cyclic descent...
Source: IEEE Transactions on Signal Processing - May 19, 2015 Category: Biomedical Engineering Source Type: research

Generalized Iterated Kalman Filter and its Performance Evaluation
In this paper, we present a generalized iterated Kalman filter (GIKF) algorithm for state estimation of a nonlinear stochastic discrete-time system with state-dependent multiplicative observation noise. The GIKF algorithm adopts the Newton–Raphson iterative optimization steps to yield an approximate maximum a posteriori estimate of the states. The mean-square estimation error (MSE) and the Cramér–Rao lower bound (CRLB) of the state estimates are also derived. In particular, the local convergence of MSE of GIKF is rigorously established. It is also proved that the GIKF yields a smaller MSE than those of...
Source: IEEE Transactions on Signal Processing - May 19, 2015 Category: Biomedical Engineering Source Type: research

Compressed Sensing for Ultrasound Computed Tomography
Ultrasound computed tomography (UCT) allows the reconstruction of quantitative tissue characteristics, such as speed of sound, mass density, and attenuation. Lowering its acquisition time would be beneficial; however, this is fundamentally limited by the physical time of flight and the number of transmission events. In this letter, we propose a compressed sensing solution for UCT. The adopted measurement scheme is based on compressed acquisitions, with concurrent randomised transmissions in a circular array configuration. Reconstruction of the image is then obtained by combining the born iterative method and total variatio...
Source: IEEE Transactions on Biomedical Engineering - May 19, 2015 Category: Biomedical Engineering Source Type: research