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This page shows you the most recent publications within this specialty of the MedWorm directory. This is page number 13.

A Multitask Learning Framework for Broadband Source-Location Mapping Using Passive Sonar
Underwater source localization via passive sonar is a challenging task due to the dynamic and complex nature of the acoustic environment. Different from approaches based on matched-field processing, this work explores broadband underwater source localization within a multitask learning (MTL) framework. Here, each task refers to a robust signal approximation problem over a single frequency. MTL provides a natural framework for exchanging information across the narrowband signal-approximation problems and constructing an aggregate (across frequencies) source-localization map. Efficient algorithms based on block coordinate de...
Source: IEEE Transactions on Signal Processing - June 9, 2015 Category: Biomedical Engineering Source Type: research

Quantization of Eigen Subspace for Sparse Representation
We propose sparse Karhunen–Loeve Transform (SKLT) method to sparse eigen subspaces. The sparsity (cardinality reduction) is achieved through the pdf-optimized quantization of basis function (vector) set. It may be considered an extension of the simple and soft thresholding (ST) methods. The merit of the proposed framework for sparse representation is presented for auto-regressive order one, AR(1), discrete process and empirical correlation matrix of stock returns for NASDAQ-100 index. It is shown that SKLT is efficient to implement and outperforms several sparsity algorithms reported in the literature. (Source: IEEE...
Source: IEEE Transactions on Signal Processing - June 9, 2015 Category: Biomedical Engineering Source Type: research

Properties and Power Spectral Densities of CP Based OQAM-OFDM Systems
Offset quadrature amplitude modulation OFDM (OQAM-OFDM) systems have low sidelobes but require complex receivers for broadband channels. To deal with this problem, cyclic prefix (CP)-based OQAM-OFDM systems have been proposed in the literature. In this paper, we study OQAM-OFDM and two existing CP based OQAM-OFDM systems and propose a new CP based system with good spectrum performance. We investigate their properties and analyze their power spectral densities (PSDs). We show that the continuous-time transmitted CP-OQAM-OFDM signal after the CP insertion is equivalent to a truncated signal obtained by inserting CP and cycli...
Source: IEEE Transactions on Signal Processing - June 9, 2015 Category: Biomedical Engineering Source Type: research

Low-intensity functional electrical stimulation can increase multidirectional trunk stiffness in able-bodied individuals during sitting
The inability to voluntarily control the trunk musculature is a major problem following spinal cord injury as it can compromise functional independence and produce unwanted secondary complications. Recent developments suggest that neuroprostheses utilizing functional electrical stimulation (FES) may be able to facilitate or restore trunk control during sitting, standing, and other tasks involving postural control. In spite of these efforts, no study to date has used low-intensity FES to increase multidirectional trunk stiffness and damping in an attempt to bolster stability while minimizing muscle fatigue. (Source: Medical...
Source: Medical Engineering and Physics - June 9, 2015 Category: Biomedical Engineering Authors: Albert H. Vette, Noel Wu, Kei Masani, Milos R. Popovic Source Type: research

Advanced Prosthetics Provide More Functional Limbs
In an experiment at the University of Pittsburgh, a woman with quadriplegia uses her thoughts to operate a robotic arm to eat a piece of chocolate (Wodlinger B et al. J Neural Eng. doi:10.1088/1741-2560/12/1/016011 [published online December 16, 2014]). In a study at Case Western Reserve University, a man who lost his hand in an accident senses the texture of a cotton ball swept along the back of his prosthetic hand (Tan DW et al. Sci Transl Med. doi: 10.1126/scitranslmed.3008669 [published online October 8, 2014]). These remarkable feats demonstrate what advances in biomedical engineering have made possible for people liv...
Source: JAMA - June 9, 2015 Category: Journals (General) Source Type: research

A dynamic multibody model of the physiological knee to predict internal loads during movement in gravitational field.
Abstract Obtaining tibio-femoral (TF) contact forces, ligament deformations and loads during daily life motor tasks would be useful to better understand the aetiopathogenesis of knee joint diseases or the effects of ligament reconstruction and knee arthroplasty. However, methods to obtain this information are either too simplified or too computationally demanding to be used for clinical application. A multibody dynamic model of the lower limb reproducing knee joint contact surfaces and ligaments was developed on the basis of magnetic resonance imaging. Several clinically relevant conditions were simulated, includin...
Source: Computer Methods in Biomechanics and Biomedical Engineering - June 9, 2015 Category: Biomedical Engineering Authors: Bersini S, Sansone V, Frigo CA Tags: Comput Methods Biomech Biomed Engin Source Type: research

Marker-Free Tracking of Facet Capsule Motion Using Polarization-Sensitive Optical Coherence Tomography.
Abstract We proposed and tested a method by which surface strains of biological tissues can be captured without the use of fiducial markers by instead, utilizing the inherent structure of the tissue. We used polarization-sensitive optical coherence tomography (PS OCT) to obtain volumetric data through the thickness and across a partial surface of the lumbar facet capsular ligament during three cases of static bending. Reflectivity and phase retardance were calculated from two polarization channels, and a power spectrum analysis was performed on each a-line to extract the dominant banding frequency (a measure of deg...
Source: Annals of Biomedical Engineering - June 9, 2015 Category: Biomedical Engineering Authors: Claeson AA, Yeh YJ, Black AJ, Akkin T, Barocas VH Tags: Ann Biomed Eng Source Type: research

Testicular biodistribution of silica-gold nanoparticles after intramuscular injection in mice.
This study investigated whether gold-silica nanoparticles could be detected in mouse testes after intramuscular injection, with a particular focus on their ability to cross the blood-testis barrier. To that purpose, well-characterized 70-nm gold core-silica shell nanoparticles were used to ensure sensitive detection using high-resolution techniques. Testes were collected at different time points corresponding to spermatogenesis stages in mice. Transmission electron microscopy and confocal microscopy were used for nanoparticle detection, and nanoparticle quantification was performed by atomic emission spectroscopy. All thes...
Source: Biomedical Microdevices - June 7, 2015 Category: Biomedical Engineering Authors: Leclerc L, Klein JP, Forest V, Boudard D, Martini M, Pourchez J, Blanchin MG, Cottier M Tags: Biomed Microdevices Source Type: research

A bio-inspired attachment mechanism for long-term adhesion to the small intestine.
Abstract To achieve long-term attachment of capsule endoscopes (CEs) and miniature biosensors in the human gastrointestinal (GI) tract, a tissue attachment mechanism (TAM) was designed, optimized and tested for safety and adhesive capabilities on excised tissue in vitro and in vivo on a live pig model. Six TAMs were tested for their attachment strength in an in vitro attachment tensile experiment in which each TAM was tested on three different proximal intestine tissue samples. The maximum strength and average value are 8.09 N and 4.54 N respectively. The initial attachment damage was tested for 10 min using a s...
Source: Biomedical Microdevices - June 7, 2015 Category: Biomedical Engineering Authors: Xie W, Kothari V, Terry BS Tags: Biomed Microdevices Source Type: research

Pump-free gradient-based micro-device enables quantitative and high-throughput bacterial growth inhibition analysis.
Abstract Antibiotic susceptibility testing is very important in antibiotic therapy. Traditional methods to determine antibiotic susceptibility include disk diffusion and broth dilution. However, these tests are always labor intensive, time-consuming, and need large amounts of reagents. In this paper, we demonstrated a novel pump-free micro-device that enables quantitative and high-throughput bacterial growth inhibition analysis. This device consists of a series of wells and diffusion-based antibiotic gradient channels. The wells serve as antibiotic sources and buffer sinks, and we could easily observe the bacterial...
Source: Biomedical Microdevices - June 7, 2015 Category: Biomedical Engineering Authors: Ran M, Wang Y, Wang S, Luo C Tags: Biomed Microdevices Source Type: research

The effect of AZD2171- or sTRAIL/Apo2L-loaded polylactic-co-glycolic acid microspheres on a subcutaneous glioblastoma model.
In this study, we investigated the potential of the highly hydrophobic AZD2171, released from modified polylactic-co-glycolic acid microspheres (PLGA-MS), to treat glioblastoma. To further demonstrate the versatile loading capacity of this system, the same PLGA formulation, which was found optimal for the loading and release of AZD2171, was tested with sTRAIL/Apo2L-a biologic drug that is very different than AZD2171 in its molecular weight, solubility, and charge. AZD2171 released from PLGA-MS was at least effective as the free drug in inhibiting endothelial growth and proliferation (in vitro), and, surprisingly, had a pro...
Source: Biomedical Microdevices - June 7, 2015 Category: Biomedical Engineering Authors: Shivinsky A, Bronshtein T, Haber T, Machluf M Tags: Biomed Microdevices Source Type: research

Identification of aldehyde reductase catalyzing the terminal step for conversion of xylose to butanetriol in engineered Escherichia coli.
Abstract Biosynthetic pathways for the production of biofuels often rely on inherent aldehyde reductases (ALRs) of the microbial host. These native ALRs play vital roles in the success of the microbial production of 1,3-propanediol, 1,4-butanediol, and isobutanol. In the present study, the main ALR for 1,2,4-butanetriol (BT) production in Escherichia coli was identified. Results of real-time PCR analysis for ALRs in EWBT305 revealed the increased expression of adhP, fucO, adhE, and yqhD genes during BT production. The highest increase of expression was observed up to four times in yqhD. Singular deletion of adhP, f...
Source: Bioprocess and Biosystems Engineering - June 6, 2015 Category: Biomedical Engineering Authors: Valdehuesa KN, Lee WK, Ramos KR, Cabulong RB, Choi J, Liu H, Nisola GM, Chung WJ Tags: Bioprocess Biosyst Eng Source Type: research

Mechanical Properties of Porcine Brain Tissue in the Coronal Plane: Interregional Variations of the Corona Radiata.
Abstract Most biomechanical models that aim to investigate traumatic brain injury consider the corona radiata as a homogeneous structure. To verify this, indentation-relaxation tests using a custom-designed indentation device were performed on the anterior, superior, and posterior region of the corona radiata in the coronal plane of the porcine brain. Using Boltzmann hereditary integral, a linear viscoelastic model with a Prony series approximation was fitted to the time-dependent shear modulus for different regions of the corona radiata, and the fit parameters were generated. The posterior region was the stiffest ...
Source: Annals of Biomedical Engineering - June 6, 2015 Category: Biomedical Engineering Authors: Chen F, Zhou J, Li Y, Wang Y, Li L, Yue H Tags: Ann Biomed Eng Source Type: research

Recognition of activities of daily living in healthy subjects using two ad-hoc classifiers
Conclusions: The performance of the classifiers varied significantly and shows that the classifier plays an important role in ADL recognition. Both RBI and CAR classifier performed better than existing state-of-the-art (NB, RF) on all ADL. Of the two ad-hoc classifiers, the CAR classifier was more accurate and is likely to be better suited than the RBI for distinguishing and recognizing complex ADL. (Source: BioMedical Engineering OnLine)
Source: BioMedical Engineering OnLine - June 6, 2015 Category: Biomedical Engineering Authors: Prabitha UrwylerLuca RampaReto StuckiMarcel BüchlerRené MüriUrs MosimannTobias Nef Source Type: research

An assessment of image distortion and CT number accuracy within a wide-bore CT extended field of view
Abstract Although wide bore computed tomography (CT) scanners provide increased space for patients, the scan field of view (sFOV) remains considerably smaller than the bore size. Consequently, patient anatomy which spans beyond the sFOV is truncated and the information is lost. As a solution, some manufacturers provide the capacity to reconstruct CT images from a partial dataset at an extended field of view (eFOV). To assess spatial distortion within this eFOV three phantoms were considered a 30 × 30 × 20 cm3 slab of solid water, the Gammex electron density CT phantom and a female anthropomorphic phantom. F...
Source: Australasian Physical and Engineering Sciences in Medicine - June 5, 2015 Category: Biomedical Engineering Source Type: research

Identification of Linear Time-Invariant Systems From Multiple Experiments
A standard assumption for consistent estimation in the errors-in-variables setting is persistency of excitation of the noise-free input signal. We relax this assumption by considering data from multiple experiments. Consistency is obtained asymptotically as the number of experiments tends to infinity. The main theoretical and algorithmic difficulties are related to the growing number of to-be-estimated initial conditions. The method proposed in the paper is based on analytic elimination of the initial conditions and optimization over the remaining parameters. The resulting estimator is consistent; however, achieving asympt...
Source: IEEE Transactions on Signal Processing - June 5, 2015 Category: Biomedical Engineering Source Type: research

Quantized Distributed Reception for MIMO Wireless Systems Using Spatial Multiplexing
We study a quantized distributed reception scenario in which a transmitter equipped with multiple antennas sends multiple streams via spatial multiplexing to a large number of geographically separated single antenna receive nodes. This approach is applicable to scenarios such as those enabled by the Internet of Things (IoT) which holds much commercial potential and could facilitate distributed multiple-input multiple-output (MIMO) communication in future systems. The receive nodes quantize their received signals and forward the quantized received signals to a receive fusion center. With global channel knowledge and forward...
Source: IEEE Transactions on Signal Processing - June 5, 2015 Category: Biomedical Engineering Source Type: research

Asymptotically Optimal Discrete-Time Nonlinear Filters From Stochastically Convergent State Process Approximations
We consider the problem of approximating optimal in the Minimum Mean Squared Error (MMSE) sense nonlinear filters in a discrete time setting, exploiting properties of stochastically convergent state process approximations. More specifically, we consider a class of nonlinear, partially observable stochastic systems, comprised by a (possibly nonstationary) hidden stochastic process (the state), observed through another conditionally Gaussian stochastic process (the observations). Under general assumptions, we show that, given an approximating process which, for each time step, is stochastically convergent to the state proces...
Source: IEEE Transactions on Signal Processing - June 5, 2015 Category: Biomedical Engineering Source Type: research

Coordinated Multicasting With Opportunistic User Selection in Multicell Wireless Systems
Physical layer multicasting with opportunistic user selection (OUS) is examined for multicell multi-antenna wireless systems. In multicast applications, a common message is to be sent by the base stations to all users in a multicast group. By adopting a two-layer encoding scheme, a rate-adaptive channel code is applied in each fading block to enable successful decoding by a chosen subset of users (which varies over different blocks) and an application layer erasure code is employed across multiple blocks to ensure that every user is able to recover the message after decoding successfully in a sufficient number of blocks. T...
Source: IEEE Transactions on Signal Processing - June 5, 2015 Category: Biomedical Engineering Source Type: research

Gaussian Mixtures Based IRLS for Sparse Recovery With Quadratic Convergence
In this paper, we propose a new class of iteratively re-weighted least squares (IRLS) for sparse recovery problems. The proposed methods are inspired by constrained maximum-likelihood estimation under a Gaussian scale mixture (GSM) distribution assumption. In the noise-free setting, we provide sufficient conditions ensuring the convergence of the sequences generated by these algorithms to the set of fixed points of the maps that rule their dynamics and derive conditions verifiable a posteriori for the convergence to a sparse solution. We further prove that these algorithms are quadratically fast in a neighborhood of a spar...
Source: IEEE Transactions on Signal Processing - June 5, 2015 Category: Biomedical Engineering Source Type: research

Tight Probabilistic SINR Constrained Beamforming Under Channel Uncertainties
In downlink multi-user beamforming, a single basestation is serving a number of users simultaneously. However, energy intended for one user may leak to other unintended users, causing interference. With signal-to-interference-plus-noise ratio (SINR) being one of the most crucial quality metrics to users, beamforming design with SINR guarantee has always been an important research topic. However, when the channel state information is not accurate, the SINR requirements become probabilistic constraints, which unfortunately are not tractable analytically for general uncertainty distribution. Therefore, existing probabilistic ...
Source: IEEE Transactions on Signal Processing - June 5, 2015 Category: Biomedical Engineering Source Type: research

Enhancing Small Cell Transmission Opportunity Through Passive Receiver Detection in Two-Tier Heterogeneous Networks
In this paper, we investigate how to embed small cells into a macro cell to enhance the performance of two-tier heterogeneous networks. Conventionally, overlay and underlay schemes are adopted by small cells, where the former enables a small cell to use the macro cell idle bands with transmitter detection, while the latter enables a small cell to use the macro cell busy bands with a certain access probability. To enhance the performance of small cells, we propose to exploit more busy band opportunities for small cells through passive receiver detection, i.e., identifying the location of an active macro user that occupies a...
Source: IEEE Transactions on Signal Processing - June 5, 2015 Category: Biomedical Engineering Source Type: research

Distributed Diffusion-Based LMS for Node-Specific Adaptive Parameter Estimation
A distributed adaptive algorithm is proposed to solve a node-specific parameter estimation problem where the nodes are interested in estimating parameters that can be of local interest, common interest to a subset of nodes and global interest to the whole network. To address the different node-specific parameter estimation problems, this novel algorithm relies on a diffusion-based implementation of different, yet coupled Least Mean Squares (LMS) algorithms, each associated with the estimation of a specific set of local, common or global parameters. The study of convergence in the mean sense reveals that the proposed algori...
Source: IEEE Transactions on Signal Processing - June 5, 2015 Category: Biomedical Engineering Source Type: research

Rank-Two Beamforming and Power Allocation in Multicasting Relay Networks
In this paper, we propose a novel single-group multicasting relay beamforming scheme. We assume a source that transmits common messages via multiple amplify-and-forward relays to multiple destinations. To increase the number of degrees of freedom in the beamforming design, the relays process two received signals jointly and transmit the Alamouti space-time block code over two different beams. Furthermore, in contrast to the existing relay multicasting scheme of the literature, we take into account the direct links from the source to the destinations. We aim to maximize the lowest received quality-of-service by choosing the...
Source: IEEE Transactions on Signal Processing - June 5, 2015 Category: Biomedical Engineering Source Type: research

Event-Based Filter Design for a Class of Nonlinear Time-Varying Systems With Fading Channels and Multiplicative Noises
In this paper, a general event-triggered framework is developed to deal with the finite-horizon $H_{infty}$ filtering problem for discrete time-varying systems with fading channels, randomly occurring nonlinearities and multiplicative noises. An event indicator variable is constructed and the corresponding event-triggered scheme is proposed. Such a scheme is based on the relative error with respect to the measurement signal in order to determine whether the measurement output should be transmitted to the filter or not. The fading channels are described by modified stochastic Rice fading models. Some uncorrelated random var...
Source: IEEE Transactions on Signal Processing - June 5, 2015 Category: Biomedical Engineering Source Type: research

Homotopy Based Algorithms for -Regularized Least-Squares
Sparse signal restoration is usually formulated as the minimization of a quadratic cost function $Vert { mbi { y}} - { mbi { A}} { mbi { x}} Vert_{2}^{2}$ where $ { mbi { A}} $ is a dictionary and $ { mbi { x}} $ is an unknown sparse vector. It is well-known that imposing an $ell _{0}$ constraint leads to an NP-hard minimization problem. The convex relaxation approach has received considerable attention, where the $ell _{0}$ -norm is replaced by the $ell _{1}$-norm. Among the many effective $ell _{1}$ solvers, the homotopy algorithm minimizes $Vert { mbi { y}} - { mbi { A}} { mbi { x}} Vert_{2}^{2}+lambda Vert { mbi { x}} ...
Source: IEEE Transactions on Signal Processing - June 5, 2015 Category: Biomedical Engineering Source Type: research

Real-time estimation of the spectral parameters of Heart Rate Variability
Publication date: Available online 5 June 2015 Source:Biocybernetics and Biomedical Engineering Author(s): Krzysztof Kudrynski , Pawel Strumillo Spectral Heart Rate Variability (HRV) parameters, LF (low frequency) and HF (high frequency), have an important role in interpreting slower and faster heart rate modulations. An online analysis method of HRV spectral parameters based on the modified Hilbert–Huang Transform (HHT) is proposed in the paper. A number of novel methods have been put forward to meet the demand of causal pre-processing of interbeat time intervals (IBI) series prior to application of HHT. Also in the r...
Source: Biocybernetics and Biomedical Engineering - June 5, 2015 Category: Biomedical Engineering Source Type: research

Estimation of light detection efficiency for different light guides used in time-resolved near-infrared spectroscopy
Publication date: Available online 3 June 2015 Source:Biocybernetics and Biomedical Engineering Author(s): Daniel Milej , Michal Kruczkowski , Michal Kacprzak , Piotr Sawosz , Roman Maniewski , Adam Liebert Time-resolved near-infrared spectroscopy is a technique enabling the assessment of changes in oxygenation and perfusion of tissue with depth discrimination. A challenge in time-resolved measurements remains to provide sufficiently high efficiency of photons detection together with high temporal resolution of the setup. The aim of this study was to compare the performance of different fiber bundles and liquid light gui...
Source: Biocybernetics and Biomedical Engineering - June 5, 2015 Category: Biomedical Engineering Source Type: research

Evaluation of the biocompatibility of a hydroxyapatite-CaTiO3 coating in vivo
Conclusion HA-CaTiO3 coating possesses similar admirable biocompatibility and osteointegration activity with HA coating, indicating a promising coating material for implants in orthopedics. (Source: Biocybernetics and Biomedical Engineering)
Source: Biocybernetics and Biomedical Engineering - June 5, 2015 Category: Biomedical Engineering Source Type: research

Development of a non-invasive diagnostic technique for acetabular component loosening in total hip replacements
One million total hip replacement (THR) operations are conducted annually worldwide, and this number is predicted to increase [1]. Within the first ten years of THR, around 10% of all implants are expected to fail, with loosening being the most common reason [2]. The diagnostic approaches to detect loosening are generally categorised into two groups: imaging and non-imaging approaches [3]. (Source: Medical Engineering and Physics)
Source: Medical Engineering and Physics - June 5, 2015 Category: Biomedical Engineering Authors: Abdullah A. Alshuhri, Timothy P. Holsgrove, Anthony W. Miles, James L. Cunningham Source Type: research

Biomechanical properties of the Marfan's aortic root and ascending aorta before and after personalised external aortic root support surgery
Marfan syndrome (MFS) is a heritable systemic connective tissue disorder with manifestations in the cardiovascular, ocular and skeletal systems [1]. Cardiovascular complications of MFS are the major cause of death in patients with this disease [2]. MFS is linked to mutations in the fibrillin 1 gene (FBN1), which is responsible for the synthesis of normal fibrillin glycoprotein. This protein is a major component of microfibrils [3]. In MFS, the structural microfibril abnormalities not only result in inherently weakened aortic connective tissue, but also in failure of the normal maintenance and repair processes. (Source: Med...
Source: Medical Engineering and Physics - June 5, 2015 Category: Biomedical Engineering Authors: S.D. Singh, X.Y. Xu, J.R. Pepper, T. Treasure, R.H. Mohiaddin Source Type: research

Evaluating the effect of increasing ceramic content on the mechanical properties, material microstructure and degradation of selective laser sintered polycaprolactone/β-tricalcium phosphate materials
Orthopaedic scaffold materials were fabricated from polycaprolactone (PCL) and composite PCL–β-tricalcium phosphate (PCL/β-TCP) powders using selective laser sintering (SLS). Incorporating β-TCP particles is desirable to promote osteogenesis. The effects of increasing β-TCP content on the material's mechanical properties and microstructure were evaluated. The wt% of β-TCP and PCL particle sizes were found to influence material microstructure and mechanical properties, with increasing ceramic content causing a small but significant increase in stiffness but significant reductions in strength. (Source: Medical Engineering and Physics)
Source: Medical Engineering and Physics - June 5, 2015 Category: Biomedical Engineering Authors: Heather Doyle, Stefan Lohfeld, Peter McHugh Source Type: research

Comparisons of node-based and element-based approaches of assigning bone material properties onto subject-specific finite element models
Subject-specific finite element (FE) models can be generated from computed tomography (CT) datasets of a bone. A key step is assigning material properties automatically onto finite element models, which remains a great challenge. This paper proposes a node-based assignment approach and also compares it with the element-based approach in the literature. Both approaches were implemented using ABAQUS. The assignment procedure is divided into two steps: generating the data file of the image intensity of a bone in a MATLAB program and reading the data file into ABAQUS via user subroutines. (Source: Medical Engineering and Physics)
Source: Medical Engineering and Physics - June 5, 2015 Category: Biomedical Engineering Authors: G. Chen, F.Y. Wu, Z.C. Liu, K. Yang, F. Cui Tags: Technical note Source Type: research

Analysis and measurement of dielectrophoretic manipulation of particles and lymphocytes using rail-type electrodes
Current technologies have been focusing on single cell analyses using microchannel flows integrated in microdevices so-called as Lab-on-a-Chip and micro total analysis systems (micro-TAS). By using the microchannel flows and microscale mechanical and electrical components integrated into these devices, individual cells can be handled, treated, and measured with high accuracy, significantly improving the analysis of biological and physical characteristics of the cells. To realize such technologies, it is essential to develop methods that can control the position of the cells and sort specific cells from others with high spe...
Source: Medical Engineering and Physics - June 5, 2015 Category: Biomedical Engineering Authors: K. Tatsumi, K. Kawano, H. Okui, H. Shintani, K. Nakabe Source Type: research

Effect of different radial hole designs on pullout and structural strength of cannulated pedicle screws
Osteoporosis is characterized by a decrease in bone mass and density which can easily lead to fractures. Osteoporosis-related fractures most commonly occur in the hip, wrist or spine. Research has demonstrated that the risk of bone fractures increases by 1.5–3 times as the standard deviation of bone mineral density (BMD) decreases, and the lowest density is found at the fracture site [1,2]. When vertebral bodies are seriously affected by osteoporosis, most pedicle screws cannot provide sufficient holding power to the screw–bone interface, leading to greater risk of loosening or failure [3,4]. (Source: Medical Engineering and Physics)
Source: Medical Engineering and Physics - June 5, 2015 Category: Biomedical Engineering Authors: Hsin-Chang Chen, Yu-Shu Lai, Wen-Chuan Chen, Jou-Wen Chen, Chia-Ming Chang, Yi-Long Chen, Shih-Tien Wang, Cheng-Kung Cheng Source Type: research

Dental wear estimation using a digital intra-oral optical scanner and an automated 3D computer vision method.
The objective of this work was to propose an automated and direct process to grade tooth wear intra-orally. Eight extracted teeth were etched with acid for different times to produce wear and scanned with an intra-oral optical scanner. Computer vision algorithms were used for alignment and comparison among models. Wear volume was estimated and visual scoring was achieved to determine reliability. Results demonstrated that it is possible to directly detect submillimeter differences in teeth surfaces with an automated method with results similar to those obtained by direct visual inspection. The investigated method proved to...
Source: Computer Methods in Biomechanics and Biomedical Engineering - June 5, 2015 Category: Biomedical Engineering Authors: Meireles AB, Vieira AW, Corpas L, Vandenberghe B, Bastos FS, Lambrechts P, Campos MM, Las Casas EB Tags: Comput Methods Biomech Biomed Engin Source Type: research

Computational modelling of mobile bearing TKA anterior-posterior dislocation.
Abstract Anterior-posterior stability in an unconstrained mobile-bearing total knee arthroplasty (TKA) and one with rotational constraints is compared in a computational model based on an ASTM test. Both TKA designs dislocate at loads greater than reported maximum in vivo forces. The posterior drawer forces (mean: 3027 N vs. 1817 N) needed to induce subluxation increase with a greater anterior jump distance (12 mm vs. 7 mm; refers to the vertical height of the anterior or posterior border of the tibial insert's articulating surface). The posterior jump distance for both tested TKA differed by 1.5 mm and had mi...
Source: Computer Methods in Biomechanics and Biomedical Engineering - June 5, 2015 Category: Biomedical Engineering Authors: Müller JH, Zakaria T, van der Merwe W, D'Angelo F Tags: Comput Methods Biomech Biomed Engin Source Type: research

Modeling Pathologies of Diastolic and Systolic Heart Failure.
Abstract Chronic heart failure is a medical condition that involves structural and functional changes of the heart and a progressive reduction in cardiac output. Heart failure is classified into two categories: diastolic heart failure, a thickening of the ventricular wall associated with impaired filling; and systolic heart failure, a dilation of the ventricles associated with reduced pump function. In theory, the pathophysiology of heart failure is well understood. In practice, however, heart failure is highly sensitive to cardiac microstructure, geometry, and loading. This makes it virtually impossible to predict...
Source: Annals of Biomedical Engineering - June 5, 2015 Category: Biomedical Engineering Authors: Genet M, Lee LC, Baillargeon B, Guccione JM, Kuhl E Tags: Ann Biomed Eng Source Type: research

Seminars in Oncology: "Finding the Forms of Cancer with Integrated Genomics Maps"
Guest Speaker: Josh Stuart, PhD Professor, Biomedical Engineering Department University of California Santa Cruz Santa Cruz, CA Tuesday, June 9, 2015 4PM Jimmy Fund Auditorium No Registration Required!  All Are Welcome! If you would like to join the Seminars in Oncology email list, please email: claudia_steele@dfci.harvard.edu (Source: DF/HCC: Latest News)
Source: DF/HCC: Latest News - June 4, 2015 Category: Cancer & Oncology Tags: Announcements Source Type: news

Effects of fatty infiltration in human livers on the backscattered statistics of ultrasound imaging
In this study, we used ultrasound Nakagami imaging to explore the effects of fatty infiltration in human livers on the statistical distribution of backscattered signals. A total of 107 patients volunteered to participate in the experiments. The livers were scanned using a clinical ultrasound scanner to obtain the raw backscattered signals for ultrasound B-mode and Nakagami imaging. Clinical scores of fatty liver disease for each patient were determined according to a well-accepted sonographic scoring system. The results showed that the Nakagami image can visualize the local backscattering properties of liver tissues. The N...
Source: Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine - June 4, 2015 Category: Biomedical Engineering Authors: Wan, Y.-L., Tai, D.-I., Ma, H.-Y., Chiang, B.-H., Chen, C.-K., Tsui, P.-H. Tags: Original Articles Source Type: research