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This page shows you the most recent publications within this specialty of the MedWorm directory. This is page number 35.

Performance Limits of Compressive Sensing-Based Signal Classification
Most of the recent compressive sensing (CS) literature has focused on sparse signal recovery based on compressive measurements. However, exact signal recovery may not be required in certain signal processing applications such as in inference problems. In this paper, we provide performance limits of classification of sparse as well as not necessarily sparse signals based on compressive measurements. When signals are not necessarily sparse, we show that Kullback-Leibler and Chernoff distances between two probability density functions under any two hypotheses are preserved up to a factor of ${{M} over {N}}$ with $M (< N)$-...
Source: IEEE Transactions on Signal Processing - May 16, 2012 Category: Biomedical Engineering Source Type: research

A “Sequentially Drilled” Joint Congruence (SeDJoCo) Transformation With Applications in Blind Source Separation and Multiuser MIMO Systems
We consider a particular form of the classical approximate joint diagonalization (AJD) problem, which we call a “sequentially drilled” joint congruence (SeDJoCo) transformation. The problem consists of a set of symmetric real-valued (or Hermitian-symmetric complex-valued) target-matrices. The number of matrices in the set equals their dimension, and the joint diagonality criterion requires that in each transformed (“diagonalized”) target-matrix, all off-diagonal elements on one specific row and column (corresponding to the matrix-index in the set) be exactly zeros, yet does not care about the ot...
Source: IEEE Transactions on Signal Processing - May 16, 2012 Category: Biomedical Engineering Source Type: research

Blind Deconvolution of Sparse Pulse Sequences Under a Minimum Distance Constraint: A Partially Collapsed Gibbs Sampler Method
For blind deconvolution of an unknown sparse sequence convolved with an unknown pulse, a powerful Bayesian method employs the Gibbs sampler in combination with a Bernoulli–Gaussian prior modeling sparsity. In this paper, we extend this method by introducing a minimum distance constraint for the pulses in the sequence. This is physically relevant in applications including layer detection, medical imaging, seismology, and multipath parameter estimation. We propose a Bayesian method for blind deconvolution that is based on a modified Bernoulli–Gaussian prior including a minimum distance constraint factor. The co...
Source: IEEE Transactions on Signal Processing - May 16, 2012 Category: Biomedical Engineering Source Type: research

Bayesian Parameter Estimation Using Single-Bit Dithered Quantization
The Bayesian parameter estimation problem using a single-bit dithered quantizer is considered. This problem arises, e.g., for channel estimation under low-precision analog-to-digital conversion (ADC) at the receiver. Based on the Bayesian Cramér-Rao lower bound (CRLB), bounds on the mean squared error are derived that hold for all dither strategies with strictly causal adaptive processing of the quantizer output sequence. In particular, any estimator using the binary quantizer output sequence is asymptotically (in the sequence length) at least $10log_{10}(pi/2)approx 1.96$ dB worse than the minimum mean squared erro...
Source: IEEE Transactions on Signal Processing - May 16, 2012 Category: Biomedical Engineering Source Type: research

IEEE Transactions on Signal Processing publication information
Source: IEEE Transactions on Signal Processing - May 16, 2012 Category: Biomedical Engineering Source Type: research

Table of Contents
Source: IEEE Transactions on Signal Processing - May 16, 2012 Category: Biomedical Engineering Source Type: research

Influence of a postural change of the swimmer's head in hydrodynamic performances using 3D CFD.
This study deals with recent researches undertaken by the authors in the field of hydrodynamics of human swimming. The aim of this numerical study was to investigate the flow around the entire swimmer's body. The results presented in this article focus on the combination of a 3D computational fluid dynamics code and the use of the k-ω turbulence model, in the range of Reynolds numbers representative of a swimming level varying from national to international competition. Emphasis is placed on the influence of a postural change of the swimmer's head in hydrodynamic performances, which is directly related to the reduction of...
Source: Computer Methods in Biomechanics and Biomedical Engineering - May 16, 2012 Category: Biomedical Engineering Authors: Popa CV, Arfaoui A, Fohanno S, Taïar R, Polidori G Tags: Comput Methods Biomech Biomed Engin Source Type: research

Influence of altered gait patterns on the hip joint contact forces.
The objective of this study was to calculate variations in the hip joint contact forces with different gait patterns. Muscle and hip joint contact forces of four children with different walking characteristics were calculated using an inverse dynamic analysis and a static optimisation algorithm. Kinematic and kinetic analyses were based on a generic musculoskeletal model scaled down to accommodate the dimensions of each child. Results showed that for all the children with altered gaits both the orientation and magnitude of the hip joint contact force deviated from normal. The child with the most severe gait deviations had ...
Source: Computer Methods in Biomechanics and Biomedical Engineering - May 16, 2012 Category: Biomedical Engineering Authors: Carriero A, Zavatsky A, Stebbins J, Theologis T, Lenaerts G, Jonkers I, Shefelbine SJ Tags: Comput Methods Biomech Biomed Engin Source Type: research

On high-cycle fatigue of 316L stents.
Abstract This paper deals with fatigue life prediction of 316L stainless steel cardiac stents. Stents are biomedical devices used to reopen narrowed vessels. Fatigue life is dominated by the cyclic loading due to the systolic and diastolic pressure and the design against premature mechanical failure is of extreme importance. Here, a life assessment approach based on the Dang Van high cycle fatigue criterion and on finite element analysis is applied to explore the fatigue reliability of 316L stents subjected to multiaxial fatigue loading. A finite element analysis of the stent vessel subjected to cyclic pressure is ...
Source: Computer Methods in Biomechanics and Biomedical Engineering - May 16, 2012 Category: Biomedical Engineering Authors: Barrera O, Makradi A, Abbadi M, Azaouzi M, Belouettar S Tags: Comput Methods Biomech Biomed Engin Source Type: research

Self-expanding stent modelling and radial force accuracy.
The objective of the study is focused on computational modelling and specifically aims to investigate how different methods of modelling stent-artery interactions can affect the results, computational time taken and computational size of the model. Various different models, each with increasing levels of complexity, are used to simulate this analysis, representing the many assumptions and simplifications used in other similar studies in order to determine what level of simplification will still allow for an accurate representation of stent radial force and resulting stress concentrations on the inner lining of the vessel d...
Source: Computer Methods in Biomechanics and Biomedical Engineering - May 16, 2012 Category: Biomedical Engineering Authors: Ní Ghriallais R, Bruzzi M Tags: Comput Methods Biomech Biomed Engin Source Type: research

Unprocessed real-time imaging of vitreoretinal surgical maneuvers using a microscope-integrated spectral-domain optical coherence tomography system
Conclusions MIOCT is capable of unprocessed imaging of the macula in human patients undergoing surgery and of unprocessed, real-time, video imaging of surgical maneuvers in model eyes. These capabilities represent an important step towards development of MIOCT for efficient, real-time imaging of manipulations during human surgery. Content Type Journal ArticleCategory MiscellaneousPages 1-8DOI 10.1007/s00417-012-2052-2Authors Paul Hahn, Department of Ophthalmology, Duke University Eye Center, Durham, NC 27710, USAJustin Migacz, Department of Biomedical Engineering, Duke University, Durham, NC 27708, ...
Source: Graefe's Archive for Clinical and Experimental Ophthalmology - May 15, 2012 Category: Opthalmology Tags: Graefe's Archive for Clinical and Experimental Ophthalmology Source Type: research

An electromagnetic “Tracker-in-Table” configuration for X-ray fluoroscopy and cone-beam CT-guided surgery
Conclusion The open frame of the WFG offers a potentially valuable configuration for electromagnetic trackers in image-guided surgery applications that are based on X-ray fluoroscopy and/or CBCT. The geometric accuracy and FOV are comparable to the conventional AFG and offers increased depth (z-direction) FOV. Incorporation directly within the operating table offers a streamlined implementation in which the tracker is in place but “invisible,” potentially simplifying tableside logistics, avoidance of the sterile field, and compatibility with X-ray imaging. Content Type Journal ArticleCategory Or...
Source: International Journal of Computer Assisted Radiology and Surgery - May 15, 2012 Category: Intensive Care Tags: International Journal of Computer Assisted Radiology and Surgery Source Type: research

Grasp modelling with a biomechanical model of the hand.
Abstract The use of a biomechanical model for human grasp modelling is presented. A previously validated biomechanical model of the hand has been used. The equilibrium of the grasped object was added to the model through the consideration of a soft contact model. A grasping posture generation algorithm was also incorporated into the model. All the geometry was represented using a spherical extension of polytopes (s-topes) for efficient collision detection. The model was used to simulate an experiment in which a subject was asked to grasp two cylinders of different diameters and weights. Different objective function...
Source: Computer Methods in Biomechanics and Biomedical Engineering - May 15, 2012 Category: Biomedical Engineering Authors: Sancho-Bru JL, Mora MC, León BE, Pérez-González A, Iserte JL, Morales A Tags: Comput Methods Biomech Biomed Engin Source Type: research

Simulation study of pO(2) distribution in induced tumour masses and normal tissues within a microcirculation environment.
In this study, an improved Krogh's cylinder model which is more realistic than the previously reported assumption that oxygen is homogeneously distributed in a microenvironment, is proposed to describe the process of the oxygen diffusion from a capillary to its surrounding environment. The capillary wall permeability is also taken into account. The simulation study is conducted and the results show that when tumour masses are implanted at the upstream part of a capillary and followed by normal tissues, the whole normal tissues suffer from hypoxia. In contrast, when normal tissues are ahead of tumour masses, their pO(2) is ...
Source: Computer Methods in Biomechanics and Biomedical Engineering - May 15, 2012 Category: Biomedical Engineering Authors: Li M, Li Y, Wen PP Tags: Comput Methods Biomech Biomed Engin Source Type: research

Removal and recovery of uranium (VI) from aqueous solutions by immobilized Aspergillus niger powder beads.
Abstract The immobilized Aspergillus niger powder beads were obtained by entrapping nonviable A. niger powder into Ca-alginate gel. The effects of pH, contact time, initial uranium (VI) concentration and biomass dosage on the biosorption of uranium (VI) onto the beads from aqueous solutions were investigated in a batch system. Biosorption equilibrium data were agreeable with Langmuir isotherm model and the maximum biosorption capacity of the beads for uranium (VI) was estimated to be 649.4 mg/g at 30 °C. The biosorption kinetics followed the pseudo-second-order model and intraparticle diffusion equation. The var...
Source: Bioprocess and Biosystems Engineering - May 15, 2012 Category: Biomedical Engineering Authors: Ding DX, Tan X, Hu N, Li GY, Wang YD, Tan Y Tags: Bioprocess Biosyst Eng Source Type: research

A perfusable microfluidic device with on-chip total internal reflection fluorescence microscopy (TIRFM) for in situ and real-time monitoring of live cells.
Abstract A microfluidic device integrated with a Total Internal Reflection (TIR)-based chip for cell observation and analysis was developed. This integrated device enables in situ Total Internal Reflection Fluorescence Microscopy (TIRFM) on adherent cells cultured under continuous medium perfusion. This TIR-based chip, allows TIRFM to be easily performed on cells without the assembly of complicated optical components and cell culture chambers. The integrated device was evaluated by tracking the movement of fluorescent beads and monitoring the location of insulin granules in mouse pancreatic β-cells. This system of...
Source: Biomedical Microdevices - May 15, 2012 Category: Biomedical Engineering Authors: Yokokawa R, Kitazawa Y, Terao K, Okonogi A, Kanno I, Kotera H Tags: Biomed Microdevices Source Type: research

Influence of unit distance and conduction velocity on the spectra of extracellular action potentials recorded with intrafascicular electrodes
We present the derivation and computational model predictions of a method to quantitatively analyse changes in the spectral components of SFAPs with an axially located intrafascicular electrode with non-radially symmetrical sensitivity function. A spatial tissue filter relationship was derived using reciprocity equations in the spatial frequency domain and transformed to time frequency. A three dimensional bioelectrical volume conductor finite element model of a recording electrode residing in a nerve fascicle was developed to explore the potential distribution in the nerve fascicle and further derive the electrode–fiber...
Source: Medical Engineering and Physics - May 14, 2012 Category: Biomedical Engineering Authors: Shaoyu Qiao, Ken Yoshida Tags: Papers Source Type: research

Theoretical study of the flow rate toward the right heart territory in case of total occlusion of the right coronary artery
Abstract: In this work, patients with severe coronary disease and chronic occlusion of the right coronary artery (RCA) are studied. In this clinical situation, the collateral circulation is an important factor in the preservation of the myocardium until reperfusion of the area at risk. An accurate estimation of collateral flow is crucial in surgical bypass planning as it can influence the outcome of a given treatment for a given patient. The evaluation of collateral flow is frequently achieved using an index (CFI, Collateral Flow Index) based on pressure measurements.Using a model of the coronary circulation based on hydra...
Source: Medical Engineering and Physics - May 14, 2012 Category: Biomedical Engineering Authors: Mahmoud Maasrani, Agnès Drochon, Majid Harmouche, Hervé Corbineau, Jean-Philippe Verhoye Tags: Papers Source Type: research

Improving the efficiency of enzyme utilization for sugar beet pulp hydrolysis.
Abstract Sugar beet pulp (SBP) is a carbohydrate-rich residue of table sugar processing. It shows promise as a feedstock for fermentable sugar and biofuel production via enzymatic hydrolysis and microbial fermentation. This research focused on the enzymatic hydrolysis of SBP and examined the effects of solid loading (2-10 %, dry basis), enzyme preparation, and enzyme recycle on the production of fermentable sugars. The enzyme partitioning to the solid and liquid phases during SBP enzymatic hydrolysis and loss during recycling were investigated using SDS-PAGE and Zymogram analysis. Without considering product inhib...
Source: Bioprocess and Biosystems Engineering - May 13, 2012 Category: Biomedical Engineering Authors: Zheng Y, Cheng YS, Yu C, Zhang R, Jenkins BM, Vandergheynst JS Tags: Bioprocess Biosyst Eng Source Type: research

Azadirachtin production by hairy root cultivation of Azadirachta indica in a modified stirred tank reactor.
Abstract Present investigation involves hairy root cultivation of Azadirachta indica in a modified stirred tank reactor under optimized culture conditions for maximum volumetric productivity of azadirachtin. The selected hairy root line (Az-35) was induced via Agrobacterium rhizogenes LBA 920-mediated transformation of A. indica leaf explants (Coimbatore variety, India). Liquid culture of the hairy roots was developed in a modified Murashige and Skoog medium (MM2). To further enhance the productivity of azadirachtin, selected growth regulators (1.0 mg/l IAA and 0.025 mg/l GA(3)), permeabilizing agent (0...
Source: Bioprocess and Biosystems Engineering - May 13, 2012 Category: Biomedical Engineering Authors: Srivastava S, Srivastava AK Tags: Bioprocess Biosyst Eng Source Type: research

Differences in regional bone metabolism at the spine and hip: a quantitative study using 18F-fluoride positron emission tomography
Conclusion The lower values of K 1, K i and SUV at the hip suggest that lower bone blood flow in the proximal femur is an important factor explaining the principal reason for the differences in bone fluoride kinetics between the LS and hip sites. Content Type Journal ArticleCategory Original ArticlePages 1-7DOI 10.1007/s00198-012-2006-xAuthors T. Puri, King’s College London, PET Imaging Centre, Imaging Sciences and Biomedical Engineering, St. Thomas’ Hospital, London, UKM. L. Frost, King’s College London, Osteoporosis Unit, Guy’s Hospital, London, UKK. M. Curran, School of Medicine and M...
Source: Osteoporosis International - May 12, 2012 Category: Orthopaedics Tags: Osteoporosis International Source Type: research

Collaborative Gaze Channelling for Improved Cooperation During Robotic Assisted Surgery.
This study demonstrates that visual guidance is an implicit yet effective way of communication during collaborative tasks for robotic surgery. Detailed experimental validation results demonstrate the potential clinical value of the proposed CGC framework. PMID: 22581476 [PubMed - as supplied by publisher]
Source: Annals of Biomedical Engineering - May 12, 2012 Category: Biomedical Engineering Authors: Kwok KW, Sun LW, Mylonas GP, James DR, Orihuela-Espina F, Yang GZ Tags: Ann Biomed Eng Source Type: research

Estimating Electrical Conductivity Tensors of Biological Tissues Using Microelectrode Arrays.
Abstract Finding the electrical conductivity of tissue is highly important for understanding the tissue's structure and functioning. However, the inverse problem of inferring spatial conductivity from data is highly ill-posed and computationally intensive. In this paper, we propose a novel method to solve the inverse problem of inferring tissue conductivity from a set of transmembrane potential and stimuli measurements made by microelectrode arrays (MEA). We first formalize the discrete forward model of transmembrane potential propagation, based on a reaction-diffusion model with an anisotropic inhomogeneous electr...
Source: Annals of Biomedical Engineering - May 12, 2012 Category: Biomedical Engineering Authors: Gilboa E, La Rosa PS, Nehorai A Tags: Ann Biomed Eng Source Type: research

Stress State and Strain Rate Dependence of the Human Placenta.
In this study, we focused on the differences in placental tissue response to different stress states (tension, compression, and shear) and different strain rates. Human placentas were obtained (n = 11) for mechanical testing and microstructure analysis. Specimens (n = 4+) were tested in compression, tension, and shear, each at three strain rates (nine testing protocols). Microstructure analysis included scanning electron microscopy, histology, and interrupted mechanical tests to observe tissue response to various loading states. Our data showed the greatest stiffness in tension, followed by compression, and then by she...
Source: Annals of Biomedical Engineering - May 12, 2012 Category: Biomedical Engineering Authors: Weed BC, Borazjani A, Patnaik SS, Prabhu R, Horstemeyer MF, Ryan PL, Franz T, Williams LN, Liao J Tags: Ann Biomed Eng Source Type: research

Qualitative Study of Prosthetic Suspension Systems on Transtibial Amputees' Satisfaction and Perceived Problems With Their Prosthetic Devices
Conclusions: The results of the survey provide a good indication that prosthetic suspension is improved with the seal-in liner as compared with the polyethylene foam liner and silicone liner with shuttle lock. However, further prospective studies are needed to investigate which system provides the most comfort and the least problems for participants.
Source: Archives of Physical Medicine and Rehabilitation - May 11, 2012 Category: Rehabilitation Authors: Sadeeq Ali, Noor Azuan Abu Osman, Mohammad Muzamil Naqshbandi, Arezoo Eshraghi, Mojtaba Kamyab, Hossein Gholizadeh Tags: Original Articles Source Type: research

Body Fat Assessment Method Using CT Images with Separation Mask Algorithm
In this study, we proposed a procedure for the automated fat assessment from computed tomography (CT) data using image processing technique. The proposed method was applied to a single-CT image as well as CT-volume data, and results were correlated to those of dual-energy X-ray absorptiometry (DEXA) that is known as the reliable method for evaluating body fat. Using single-CT images, correlation coefficients between DEXA and the automated assessment and DEXA and the manual assessment were 0.038 and 0.058, respectively (P > 0.05). Hence, there was no significant correlation between three methods using the propose...
Source: Journal of Digital Imaging - May 10, 2012 Category: Radiology Tags: Journal of Digital Imaging Source Type: research

Micro/nanoscale technologies for the development of hormone-expressing islet-like cell clusters.
Abstract Insulin-expressing islet-like cell clusters derived from precursor cells have significant potential in the treatment of type-I diabetes. Given that cluster size and uniformity are known to influence islet cell behavior, the ability to effectively control these parameters could find applications in the development of anti-diabetic therapies. In this work, we combined micro and nanofabrication techniques to build a biodegradable platform capable of supporting the formation of islet-like structures from pancreatic precursors. Soft lithography and electrospinning were used to create arrays of microwells (150-5...
Source: Biomedical Microdevices - May 10, 2012 Category: Biomedical Engineering Authors: Gallego-Perez D, Higuita-Castro N, Reen RK, Palacio-Ochoa M, Sharma S, Lee LJ, Lannutti JJ, Hansford DJ, Gooch KJ Tags: Biomed Microdevices Source Type: research

Magnetic resonance 4D flow analysis of cerebrospinal fluid dynamics in Chiari I malformation with and without syringomyelia
Conclusions 4D-PC flow imaging allowed comprehensive analysis of CSF flow in patients with Chiari I malformation. Alterations of CSF hydrodynamics were most pronounced in patients with syringomyelia. Key Points • Analysis of CSF flow is important in patients with Chiari I malformation • 4D-PC MRI allows analysis of CSF in patients with Chiari I. • Chiari I patients show characteristic qualitative and quantitative alterations of CSF flow. • Alterations of CSF hydrodynamics are most pronounced in patients with associated syringomyelia. Content Type...
Source: European Radiology - May 9, 2012 Category: Radiology Tags: European Radiology Source Type: research

Corrigendum: Spatial variation of permittivity of an electrolyte solution in contact with a charged metal surface: a mini review.
PMID: 22571464 [PubMed - as supplied by publisher]
Source: Computer Methods in Biomechanics and Biomedical Engineering - May 9, 2012 Category: Biomedical Engineering Authors: Gongadze E, van Rienen U, Kralj-Iglič V, Iglič A Tags: Comput Methods Biomech Biomed Engin Source Type: research

Numerical simulation of the remodelling process of trabecular architecture around dental implants.
In this study, finite element simulations were implemented to predict the evolution of microarchitecture around four implant systems using a previously developed model that combines both adaptive and microdamage-based mechano-sensory mechanisms in bone remodelling process. Changes in the trabecular architecture around dental implants were mainly focused. The simulation results indicate that the orientational and ladder-like architecture around the implants predicted herein is in good agreement with those observed in animal experiments and clinical observations. The proposed algorithms were shown to be effective in simulati...
Source: Computer Methods in Biomechanics and Biomedical Engineering - May 9, 2012 Category: Biomedical Engineering Authors: Wang C, Wang L, Liu X, Fan Y Tags: Comput Methods Biomech Biomed Engin Source Type: research

A comparative study of muscle force estimates using Huxley's and Hill's muscle model.
Abstract Determination of muscle forces in individual muscles is often essential to assess optimal performance of human motion. Inverse dynamic methods based on the kinematics of the given motion and on the use of optimisation approach are the most widely used for muscle force estimation. The aim of this study was to estimate how the choice of muscle model influences predicted muscle forces. Huxley's (1957, Prog Biophys Biop Chem. 7: 255-318) and Hill's (1938, Proc R Soc B. 126: 136-195) muscle models were used for determination of muscle forces of two antagonistic muscles of the lower extremity during cycling. Hux...
Source: Computer Methods in Biomechanics and Biomedical Engineering - May 9, 2012 Category: Biomedical Engineering Authors: Cadova M, Vilimek M, Daniel M Tags: Comput Methods Biomech Biomed Engin Source Type: research

Finite element analysis of the influence of loading rate on a model of the full lumbar spine under dynamic loading conditions
Abstract Despite an increase in the number of experimental and numerical studies dedicated to spinal trauma, the influence of the rate of loading or displacement on lumbar spine injuries remains unclear. In the present work, we developed a bio-realistic finite element model (FEM) of the lumbar spine using a comprehensive geometrical representation of spinal components and material laws that include strain rate dependency, bone fracture, and ligament failure. The FEM was validated against published experimental data and used to compare the initiation sites of spinal injuries under low (LD) and high (HD) dynam...
Source: Medical and Biological Engineering and Computing - May 8, 2012 Category: Biomedical Engineering Tags: Medical and Biological Engineering and Computing Source Type: research

The Multi-Scale Modelling of Coronary Blood Flow.
Abstract Coronary flow is governed by a number of determinants including network anatomy, systemic afterload and the mechanical interaction with the myocardium throughout the cardiac cycle. The range of spatial scales and multi-physics nature of coronary perfusion highlights a need for a multiscale framework that captures the relevant details at each level of the network. The goal of this review is to provide a compact and accessible introduction to the methodology and current state of the art application of the modelling frameworks that have been used to study the coronary circulation. We begin with a brief descri...
Source: Annals of Biomedical Engineering - May 8, 2012 Category: Biomedical Engineering Authors: Lee J, Smith NP Tags: Ann Biomed Eng Source Type: research

Mechanics of a Fiber Network Within a Non-Fibrillar Matrix: Model and Comparison with Collagen-Agarose Co-gels.
Abstract While collagen is recognized as the predominant mechanical component of soft connective tissues, the role of the non-fibrillar matrix (NFM) is less well understood. Even model systems, such as the collagen-agarose co-gel, can exhibit complex behavior, making it difficult to identify relative contributions of specific tissue constituents. In the present study, we developed a two-component microscale model of collagen-agarose tissue analogs and used it to elucidate the interaction between collagen and NFM in uniaxial tension. Collagen fibers were represented with Voronoi networks, and the NFM was modeled as ...
Source: Annals of Biomedical Engineering - May 8, 2012 Category: Biomedical Engineering Authors: Lake SP, Hadi MF, Lai VK, Barocas VH Tags: Ann Biomed Eng Source Type: research

Multiscale Imaging and Computational Modeling of Blood Flow in the Tumor Vasculature.
Abstract The evolution in our understanding of tumor angiogenesis has been the result of pioneering imaging and computational modeling studies spanning the endothelial cell, microvasculature and tissue levels. Many of these primary data on the tumor vasculature are in the form of images from pre-clinical tumor models that provide a wealth of qualitative and quantitative information in many dimensions and across different spatial scales. However, until recently, the visualization of changes in the tumor vasculature across spatial scales remained a challenge due to a lack of techniques for integrating micro- and macr...
Source: Annals of Biomedical Engineering - May 8, 2012 Category: Biomedical Engineering Authors: Kim E, Stamatelos S, Cebulla J, Bhujwalla ZM, Popel AS, Pathak AP Tags: Ann Biomed Eng Source Type: research

Letter to the Editor: "Sensitivity of the Wolf's and Rosenstein's Algorithms to Evaluate Local Dynamic Stability from Small Gait Data Sets"
PMID: 22565818 [PubMed - as supplied by publisher]
Source: Annals of Biomedical Engineering - May 8, 2012 Category: Biomedical Engineering Authors: Bruijn SM, Meijer OG, Rispens SM, Daffertshofer A, van Dieën JH Tags: Ann Biomed Eng Source Type: research

Layered water in crystal interfaces as source for bone viscoelasticity: arguments from a multiscale approach.
Abstract Extracellular bone material can be characterised as a nanocomposite where, in a liquid environment, nanometre-sized hydroxyapatite crystals precipitate within as well as between long fibre-like collagen fibrils (with diameters in the 100 nm range), as evidenced from neutron diffraction and transmission electron microscopy. Accordingly, these crystals are referred to as 'interfibrillar mineral' and 'extrafibrillar mineral', respectively. From a topological viewpoint, it is probable that the mineralisations start on the surfaces of the collagen fibrils ('mineral-encrusted fibrils'), from where the crystals ...
Source: Computer Methods in Biomechanics and Biomedical Engineering - May 8, 2012 Category: Biomedical Engineering Authors: Eberhardsteiner L, Hellmich C, Scheiner S Tags: Comput Methods Biomech Biomed Engin Source Type: research

Kinetics of hydrogen peroxide decomposition by catalase: hydroxylic solvent effects.
Abstract The effect of water-alcohol (methanol, ethanol, propan-1-ol, propan-2-ol, ethane-1,2-diol and propane-1,2,3-triol) binary mixtures on the kinetics of hydrogen peroxide decomposition in the presence of bovine liver catalase is investigated. In all solvents, the activity of catalase is smaller than in water. The results are discussed on the basis of a simple kinetic model. The kinetic constants for product formation through enzyme-substrate complex decomposition and for inactivation of catalase are estimated. The organic solvents are characterized by several physical properties: dielectric constant (D), hydr...
Source: Bioprocess and Biosystems Engineering - May 8, 2012 Category: Biomedical Engineering Authors: Raducan A, Cantemir AR, Puiu M, Oancea D Tags: Bioprocess Biosyst Eng Source Type: research

A polymer microfluidic chip for quantitative detection of multiple water- and foodborne pathogens using real-time fluorogenic loop-mediated isothermal amplification.
In this study, a disposable polymer microfluidic chip for quantitative detection of multiple pathogens using isothermal nucleic acid amplification was developed. The chip contains an array of 15 interconnected reaction wells with dehydrated primers for loop-mediated isothermal amplification (LAMP), and requires only a single pipetting step for dispensing of sample. To improve robustness of loading and amplification, hydrophobic air vents and microvalves were monolithically integrated in the multi-layered structure of the chip using an inexpensive knife plotter. For quantification, LAMP was performed with a highly fluoresce...
Source: Biomedical Microdevices - May 8, 2012 Category: Biomedical Engineering Authors: Tourlousse DM, Ahmad F, Stedtfeld RD, Seyrig G, Tiedje JM, Hashsham SA Tags: Biomed Microdevices Source Type: research

Erratum to: Stiffness Analysis of Cardiac Electrophysiological Models.
PMID: 22565813 [PubMed - as supplied by publisher]
Source: Annals of Biomedical Engineering - May 8, 2012 Category: Biomedical Engineering Authors: Spiteri RJ, Dean RC Tags: Ann Biomed Eng Source Type: research

Erratum to: In Vitro Characterization of Bicuspid Aortic Valve Hemodynamics Using Particle Image Velocimetry.
PMID: 22565814 [PubMed - as supplied by publisher]
Source: Annals of Biomedical Engineering - May 8, 2012 Category: Biomedical Engineering Authors: Saikrishnan N, Yap CH, Milligan NC, Vasilyev NV, Yoganathan AP Tags: Ann Biomed Eng Source Type: research

Automated setup of functional electrical stimulation for drop foot using a novel 64 channel prototype stimulator and electrode array: Results from a gait-lab based study
Abstract: Functional electrical stimulation is commonly used to correct drop foot following stroke or multiple sclerosis. This technique is successful for many patients, but previous studies have shown that a significant minority have difficulty identifying correct sites to place the electrodes in order to produce acceptable foot movement. Recently there has been some interest in the use of ‘virtual electrodes’, the process of stimulating a subset of electrodes chosen from an array, thus allowing the site of stimulation to be moved electronically rather than physically. We have developed an algorithm for automatically ...
Source: Medical Engineering and Physics - May 7, 2012 Category: Biomedical Engineering Authors: Ben W. Heller, Alison J. Clarke, Timothy R. Good, T. Jamie Healey, Siva Nair, Emma J. Pratt, Mark L. Reeves, Jill M. van der Meulen, Anthony T. Barker Tags: Papers Source Type: research

Optimised in vitro applicable loads for the simulation of lateral bending in the lumbar spine
Abstract: In in vitro studies of the lumbar spine simplified loading modes (compressive follower force, pure moment) are usually employed to simulate the standard load cases flexion-extension, axial rotation and lateral bending of the upper body. However, the magnitudes of these loads vary widely in the literature. Thus the results of current studies may lead to unrealistic values and are hardly comparable. It is still unknown which load magnitudes lead to a realistic simulation of maximum lateral bending.A validated finite element model of the lumbar spine was used in an optimisation study to determine which magnitudes of...
Source: Medical Engineering and Physics - May 7, 2012 Category: Biomedical Engineering Authors: Marcel Dreischarf, Antonius Rohlmann, Georg Bergmann, Thomas Zander Tags: Technical Notes Source Type: research