MedWorm.com provides a medical RSS filtering service. Over 6000 RSS medical sources are combined and output via different filters. This feed contains the latest items from the 'Computer Methods in Biomechanics and Biomedical Engineering' source. Tue, 07 Feb 2012 07:42:47 +0100 http://www.medworm.com/index.php?rid=5639994&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22268530%26dopt%3DAbstract Authors: Ali AH, Cowan AB, Gregory JS, Aspden RM, Meakin JR Abstract The 2D shape of the lumbar spine in the sagittal plane can be determined from lordosis angles measured between the corresponding end-plates of the vertebral bodies or by using an active shape model (ASM) of the vertebral body outline. The ASM was previously shown to be a more efficient and reliable method, but its accuracy has not been assessed. The aim of this study was to determine the accuracy of an ASM for characterising lumbar spine shape and compare this to conventional measurements. Images of 25 different lumbar spine shapes were generated and measured, using both methods, by three independent observers. The accuracy of the ASM, determined from lordosis angles predicted by the model, was found to be better ... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5639994 Mon, 30 Jan 2012 07:54:13 +0100 5639994 http://www.medworm.com/index.php?rid=5639998&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22263691%26dopt%3DAbstract Authors: Altunkaya S, Kara S, Görmüş N, Herdem S Abstract In this article, the spectral features of first heart sounds (S1) and second heart sounds (S2), which comprise the mechanical heart valve sounds obtained after aortic valve replacement (AVR) and mitral valve replacement (MVR), are compared to find out the effect of mechanical heart valve replacement and recording area on S1 and S2. For this aim, the Welch method and the autoregressive (AR) method are applied on the S1 and S2 taken from 66 recordings of 8 patients with AVR and 98 recordings from 11 patients with MVR, thereby yielding power spectrum of the heart sounds. Three features relating to frequency of heart sounds and three features relating to energy of heart sounds are obtained. Results show that in comparison to ... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5639998 Mon, 23 Jan 2012 05:00:00 +0100 5639998 http://www.medworm.com/index.php?rid=5639997&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22263706%26dopt%3DAbstract Authors: Gross T, Pahr DH, Peyrin F, Zysset PK Abstract At the tissue level, the local material properties of human cancellous bone are heterogeneous due to constant remodelling. Since standard high-resolution computed tomography scanning methods are unable to capture this heterogeneity in detail, local differences in mineralisation are normally not incorporated in computational models. To investigate the effects of heterogeneous mineral distribution on the apparent elastic properties, 40 cancellous bone samples from the human femoral neck were scanned by means of synchrotron radiation microcomputed tomography (SRμCT). SRμCT-based micromechanical finite element models that accounted for mineral heterogeneity were compared with homogeneous models. Evaluation of the apparent stiffn... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5639997 Mon, 23 Jan 2012 05:00:00 +0100 5639997 http://www.medworm.com/index.php?rid=5639996&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22263753%26dopt%3DAbstract Authors: Tang X, Xia L, Liu W, Peng Y, Gao T, Zeng Y Abstract A hidden Markov model (HMM) of electrocardiogram (ECG) signal is presented for detection of myocardial ischemia. The time domain signals that are recorded by the ECG before and during the episode of local ischemia were pre-processed to produce input sequences, which is needed for the model training. The model is also verified by test data, and the results show that the models have certain function for the detection of myocardial ischemia. The algorithm based on HMM provides a possible approach for the timely, rapid and automatic diagnosis of myocardial ischemia, and also can be used in portable medical diagnostic equipment in the future. PMID: 22263753 [PubMed - as supplied by publisher] (Source: Computer Methods in ... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5639996 Mon, 23 Jan 2012 05:00:00 +0100 5639996 http://www.medworm.com/index.php?rid=5639995&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22263808%26dopt%3DAbstract Authors: Gongadze E, van Rienen U, Kralj-Iglič V, Iglič A Abstract Contact between a charged metal surface and an electrolyte implies a particular ion distribution near the charged surface, i.e. the electrical double layer. In this mini review, different mean-field models of relative (effective) permittivity are described within a simple lattice model, where the orientational ordering of water dipoles in the saturation regime is taken into account. The Langevin-Poisson-Boltzmann (LPB) model of spatial variation of the relative permittivity for point-like ions is described and compared to a more general Langevin-Bikerman (LB) model of spatial variation of permittivity for finite-sized ions. The Bikerman model and the Poisson-Boltzmann model are derived as limiting cases. It is sho... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5639995 Mon, 23 Jan 2012 05:00:00 +0100 5639995 http://www.medworm.com/index.php?rid=5621963&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22260153%26dopt%3DAbstract This article presents an examination and validation of a method to measure the field deceleration of a manual wheelchair (MWC) and to calculate the rolling resistances properties of the front and rear wheels. This method was based on the measurements of the MWC deceleration for various load settings from a 3D accelerometer. A mechanical model of MWC deceleration was developed which allowed computing the rolling resistance factors of front and rear wheels on a tested surface. Four deceleration sets were conducted on two paths on the same ground to test the repeatability. Two other deceleration sets were conducted using different load settings to compute the rolling resistance parameters (RPs). The theoretical decelerations of three load settings were computed and compared with the measured ... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5621963 Fri, 20 Jan 2012 05:00:00 +0100 5621963 http://www.medworm.com/index.php?rid=5621964&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22260089%26dopt%3DAbstract Authors: Gentil F, Parente M, Martins P, Garbe C, Paço J, Ferreira AJ, Tavares JM, Jorge RN Abstract The human ear is a complex biomechanical system and is divided into three parts: outer, middle and inner ear. The middle ear is formed by ossicles (malleus, incus and stapes), ligaments, muscles and tendons, which transfers sound vibrations from the eardrum to the inner ear, linking with mastoid and Eustachian tube. In this work, a finite element modelling of the tympano-ossicular system of the middle ear was developed. A dynamic study based on a structural response to harmonic vibrations, for a sound pressure level (SPL) of 110, 120 and 130 dB SPL applied in the eardrum, is presented. The connection between the ossicles is made using a contact formulation. The model includes the ... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5621964 Thu, 19 Jan 2012 05:00:00 +0100 5621964 http://www.medworm.com/index.php?rid=5602077&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22248290%26dopt%3DAbstract Authors: Wenk JF, Ge L, Zhang Z, Soleimani M, Potter DD, Wallace AW, Tseng E, Ratcliffe MB, Guccione JM Abstract Numerical modelling of the cardiovascular system is becoming an important tool for assessing the influence of heart disease and treatment therapies. In the current study, we present an approach for modelling the interaction between the heart and the circulatory system. This was accomplished by creating animal-specific biventricular finite element (FE) models, which characterise the mechanical response of the heart, and by coupling them to a lumped-parameter model that represents the systemic and pulmonic circulatory system. In order to minimise computation time, the coupling was enforced in a weak (one-way) manner, where the ventricular pressure-volume relationships were... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5602077 Mon, 16 Jan 2012 05:00:00 +0100 5602077 http://www.medworm.com/index.php?rid=5602079&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22242639%26dopt%3DAbstract Authors: Kuznetsov AV Abstract A model describing the propagation of positive injury signals from the lesion site in an axon towards the neuron soma is described. It is assumed that these signals are driven by dynein molecular motors. An analytical solution that accounts for the probability density function (pdf) of a dynein velocity distribution is obtained. Two examples of pdf of dynein velocity distributions that follow from the results published in Ross et al. (2006, Processive bidirectional motion of dynein-dynactin complexes in vitro. Nat Cell Biol. 8:562-570) and Deinhardt et al. (2006, Rab5 and Rab7 control endocytic sorting along the axonal retrograde transport pathway. Neuron 52:293-305) are considered. The effect of dynein velocity distribution on the rate of spreading o... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5602079 Fri, 13 Jan 2012 05:00:00 +0100 5602079 http://www.medworm.com/index.php?rid=5602078&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22242679%26dopt%3DAbstract Authors: Lalone EA, McDonald CP, Ferreira LM, Peters TM, King GW, Johnson JA Abstract Identifying joint contact in articular joints is important for both the biomechanical investigation of joint mechanics and the study of osteoarthritis. The purpose of this study is to develop a proximity mapping technique to non-invasively determine joint congruency, as a surrogate of joint contact. To illustrate the capabilities of this algorithm, a cadaveric upper extremity was positioned at varying degrees of elbow flexion. This technique was validated using a gold standard experimental casting technique. The pattern of the cast showed an excellent agreement with the generated proximity map using the inter-bone distance algorithm. The results from this study agree with the results of previous s... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5602078 Fri, 13 Jan 2012 05:00:00 +0100 5602078 http://www.medworm.com/index.php?rid=5602080&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22235878%26dopt%3DAbstract Authors: Gillett JG, Barrett RS, Lichtwark GA Abstract Manual tracking of muscle fascicle length changes from ultrasound images is a subjective and time-consuming process. The purpose of this study was to assess the repeatability and accuracy of an automated algorithm for tracking fascicle length changes in the medial gastrocnemius (MG) muscle during passive length changes and active contractions (isometric, concentric and eccentric) performed on a dynamometer. The freely available, automated tracking algorithm was based on the Lucas-Kanade optical flow algorithm with an affine optic flow extension, which accounts for image translation, dilation, rotation and shear between consecutive frames of an image sequence. Automated tracking was performed by three experienced assessors, and ... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5602080 Wed, 11 Jan 2012 05:00:00 +0100 5602080 http://www.medworm.com/index.php?rid=5578382&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22229381%26dopt%3DAbstract Authors: Al-Kasasbeh R, Korenevskiy N, Ionescou F, Alshamasin M, Kuzmin A Abstract Many theories of reflexology use ancient concepts which do not coincide with the modern medical terminology of anatomy, physiology and biophysics. This substantially reduces the trust of physicians in reflexology methods. During this research, several mathematical models for the interaction of the internal and biological active points of meridian structures have been proposed. The analysis of these models allows the specification of a list of heart diseases for which reflex diagnostics and reflex therapy methods are most effective and also allows increasing the effectiveness of these procedures. It is shown that good results for the prediction and early diagnosis of diseases from the reaction energy ... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5578382 Tue, 10 Jan 2012 05:00:00 +0100 5578382 http://www.medworm.com/index.php?rid=5578381&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22229447%26dopt%3DAbstract Authors: Oldfield M, Dini D, Giordano G, Rodriguez Y Baena F Abstract Detailed finite element modelling of needle insertions into soft tissue phantoms encounters difficulties of large deformations, high friction, contact loading and material failure. This paper demonstrates the use of cohesive elements in high-resolution finite element models to overcome some of the issues associated with these factors. Experiments are presented enabling extraction of the strain energy release rate during crack formation. Using data from these experiments, cohesive elements are calibrated and then implemented in models for validation of the needle insertion process. Successful modelling enables direct comparison of finite element and experimental force-displacement plots and energy distributions. R... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5578381 Tue, 10 Jan 2012 05:00:00 +0100 5578381 http://www.medworm.com/index.php?rid=5578380&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22229479%26dopt%3DAbstract Authors: Xue X, Bailey C Abstract This paper investigates the effectiveness of using curved constrictions in the bifurcation region of T-type fluid separators for promoting flow development in the intervals between bifurcations. A design of biofluid separator is proposed and a mathematical analysis and a numerical simulation of the blood flow in microchannels are conducted. The design is based on a modification of an existing T-shaped biochip device which consists of a main channel and a series of perpendicularly positioned side channels. By means of bifurcation effect, the blood is separated into plasma concentration flow from the side channels and blood cell concentration flow from the main channel. In this design, curved constrictions are inserted between bifurcations to replace... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5578380 Tue, 10 Jan 2012 05:00:00 +0100 5578380 http://www.medworm.com/index.php?rid=5578404&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22220925%26dopt%3DAbstract Authors: Huang TC, Cheng DC, Schmidt-Trucksäss A, Schütz UH Abstract In this paper, an automated method to localise the right superficial femoral artery (SFA) and identify its boundary on magnetic resonance imaging (MRI) sequences without contrast medium injection is proposed. Some anatomical knowledge combined with the mathematical morphology is used to distinguish SFA from other vessels. Afterwards, the directional gradient, continuity and the local contrast are applied as features to identify the artery's boundary using dynamic programming. The accuracy analysis shows that the system has average unsigned errors 3.1 ± 3.1% on five sequences compared to experts' manual tracings. PMID: 22220925 [PubMed - as supplied by publisher] (Source: Computer Methods in Biomechanics a... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5578404 Fri, 06 Jan 2012 05:00:00 +0100 5578404 http://www.medworm.com/index.php?rid=5578403&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22220946%26dopt%3DAbstract Authors: Malvè M, Chandra S, López-Villalobos JL, Finol EA, Ginel A, Doblaré M Abstract A computational fluid dynamics model of a healthy, a stenotic and a post-operatory stented human trachea was developed to study the respiration under physiological boundary conditions. For this, outflow pressure waveforms were computed from patient-specific spirometries by means of a method that allows to compute the peripheral impedance of the truncated bronchial generation, modelling the lungs as fractal networks. Intratracheal flow pattern was analysed under different scenarios. First, results obtained using different outflow conditions were compared for the healthy trachea in order to assess the importance of using impedance-based conditions. The resulted intratracheal pressures were affe... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5578403 Fri, 06 Jan 2012 05:00:00 +0100 5578403 http://www.medworm.com/index.php?rid=5578402&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22224406%26dopt%3DAbstract Authors: John CT, Anderson FC, Higginson JS, Delp SL Abstract A fundamental question in movement science is how humans perform stable movements in the presence of disturbances such as contact with objects. It remains unclear how the nervous system, with delayed responses to disturbances, maintains the stability of complex movements. We hypothesised that intrinsic muscle properties (i.e. the force-length-velocity properties of muscle fibres and tendon elasticity) may help stabilise human walking by responding instantaneously to a disturbance and providing forces that help maintain the movement trajectory. To investigate this issue, we generated a 3D muscle-driven simulation of walking and analysed the changes in the simulation's motion when a disturbance was applied to models with a... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5578402 Fri, 06 Jan 2012 05:00:00 +0100 5578402 http://www.medworm.com/index.php?rid=5578401&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22224592%26dopt%3DAbstract Authors: Singh WJ, Nagarajan B Abstract Breast cancer screening is currently performed by mammography, which is limited by overlying anatomy and dense breast tissue. Computer-aided detection (CAD) systems can serve as a double reader to improve radiologist performance. In this paper, we have applied a novel approach to segmentation of suspicious region by mammogram and classification based on hybrid features with learning classifier. We formulated differentiation of lesion from normal tissue as a supervised learning problem, and applied this learning method to develop the classification algorithm. The algorithm has been verified with 164 mammograms in the mini Mammographic Image Analysis Society database. The experimental results show that the detection method has a sensitivity of ... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5578401 Fri, 06 Jan 2012 05:00:00 +0100 5578401 http://www.medworm.com/index.php?rid=5578396&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22224636%26dopt%3DAbstract In this study, a methodology for studying porous structures was proposed. The extended finite element method (XFEM) in conjunction with a penalty approach was used to model the porous structures. The holes were considered to have very small Young's modulus, thus they could be treated as inclusions in a matrix. The level set method was applied to describe the internal boundaries of the holes. Various porous structures were investigated. A practical example of the porous structures, which was the microstructure of a trabecular bone, was examined to show the capability of the proposed methodology. The aim of the study was to demonstrate that various complicated porous structures can be modelled efficiently by the XFEM without any major modification to the existing formula. PMID: 22224636 ... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5578396 Fri, 06 Jan 2012 05:00:00 +0100 5578396 http://www.medworm.com/index.php?rid=5578395&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22224674%26dopt%3DAbstract Authors: García-Herrera CM, Celentano DJ, Cruchaga MA Abstract This work presents experiments, modelling and simulation aimed at describing the mechanical behaviour of the human aortic arch during the bending and pressurisation test. The main motivation is to describe the material response of this artery when it is subjected to large quasi-static deformations in three different stages: bending, axial stretching and internal pressurisation. The sample corresponds to a young artery without cardiovascular pathologies. The pressure levels are within the normal and hypertension physiological ranges. The two principal findings of this work are firstly, the material characterisation performed via tensile test measurements that serve to derive the material parameters of a hyperelastic iso... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5578395 Fri, 06 Jan 2012 05:00:00 +0100 5578395 http://www.medworm.com/index.php?rid=5578394&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22224724%26dopt%3DAbstract This study aimed to show that the regional differences in annulus mechanical behaviour could be reproduced by considering only fibre orientation changes. Using the finite element method, a lumbar annulus was modelled as a poro-hyperelastic material in which fibres were represented by a direction-dependent strain energy density term. Fibre orientations were calibrated to reproduce the annulus tensile behaviours measured for four different regions: posterior outer, anterior outer, posterior inner and anterior inner. The back-calculated fibre angles and regional patterns as well as the global disc behaviour were comparable with anatomical descriptions reported in the literature. It was concluded that annulus fibre variations might be an effective tool to calibrate lumbar spine IVD and segment... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5578394 Fri, 06 Jan 2012 05:00:00 +0100 5578394 http://www.medworm.com/index.php?rid=5578393&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22224793%26dopt%3DAbstract Authors: Hayashi S, Nishiyama T, Fujishiro T, Kanzaki N, Shibanuma N, Kobashi S, Kurosaka M Abstract Most of computer-assisted planning systems need to determine the anatomical axis based on the anterior pelvic plane (APP). We analysed that our new system is more reproducible for determination of APP than previous methods. A pelvic model bone and two subjects suffering from hip osteoarthritis were evaluated. Multidetector-row computed tomography (MDCT) images were scanned with various rotations by MDCT scanner. The pelvic rotation was calibrated using silhouette images. APP was determined by an optimisation technique. The values of variation of APP caused by pelvic rotation were analysed with statistical analysis. APP determination with calibration and optimisation was most reprodu... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5578393 Fri, 06 Jan 2012 05:00:00 +0100 5578393 http://www.medworm.com/index.php?rid=5578392&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22224843%26dopt%3DAbstract Authors: Grytz R, Downs JC Abstract Numerical simulations or inverse numerical analyses of individual eyes or eye segments are often based on an eye-specific geometry obtained from in vivo medical images such as computed tomography (CT) scans or from in vitro 3D digitiser scans. These eye-specific geometries are usually measured while the eye is subjected to internal pressure. Due to the nonlinear stiffening of the collagen fibril network in the eye, numerical incorporation of the pre-existing stress/strain state may be essential for realistic eye-specific computational simulations. Existing prestressing methods either compute accurate predictions of the prestressed state or guarantee a unique solution. In this contribution, a forward incremental prestressing method is presented wh... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5578392 Fri, 06 Jan 2012 05:00:00 +0100 5578392 http://www.medworm.com/index.php?rid=5578391&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22224865%26dopt%3DAbstract The objective of this study was to investigate a bioreactor suitable for human bladder regeneration. Simulations were performed using the computational fluid dynamic tools. The thickness of the bladder scaffold was 3 mm, similar to the human bladder, and overall hold-up volume within the spherical shape scaffold was 755 ml. All simulations were performed using (i) Brinkman equation on porous regions using the properties of 1% chitosan-1% gelatin structures, (ii) Michaelis-Menten type rate law nutrient consumption for smooth muscle cells (SMCs) and (iii) Mackie-Meares relationship for determining effective diffusivities. Steady state simulations were performed using flow rates from 0.5 to 5 ml/min. Two different inlet shapes: (i) straight entry at the centre (Design 1) and (ii) entry wit... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5578391 Fri, 06 Jan 2012 05:00:00 +0100 5578391 http://www.medworm.com/index.php?rid=5578390&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22224913%26dopt%3DAbstract This study analysed the resulting range of motion (ROM), facet contact force (FCF), inlay contact pressure (ICP) and stress distribution of adjacent discs. The FE results indicated that the ROM of both surgical constructs was related to the preload application method and magnitude; differences in the ROM were within 7% for the ALIF model and 32% for the ADR model. Following the application of the FL and after increasing the FL magnitude, the FCF of the ADR model gradually increased, reaching 45% at the implanted level in torsion. The maximum ICP gradually decreased by 34.1% in torsion and 28.4% in lateral bending. This study concluded that the preload magnitude and application method affect the biomechanical behaviour of the lumbar spine. For the ADR, remarkable alteration was observed whi... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5578390 Fri, 06 Jan 2012 05:00:00 +0100 5578390 http://www.medworm.com/index.php?rid=5578389&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22224937%26dopt%3DAbstract Authors: Campolo D Abstract This paper is concerned with the analysis and the numerical evaluation from experimental measurements of the static, Cartesian stiffness of wrist joints, in particular the human wrist. The primary aim is to extend from Euclidean spaces to so(3), the group of rigid body rotations, previous methods for assessing the end-point stiffness of the human arm, typically performed via a robotic manipulandum. As a first step, the geometric definition of Cartesian stiffness from current literature is specialised to the group so(3). Emphasis is placed on the choice of the unique, natural, affine connection on so(3) which guarantees symmetry of the stiffness matrix in presence of conservative fields for any configuration, also out of equilibrium. As the main contribut... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5578389 Fri, 06 Jan 2012 05:00:00 +0100 5578389 http://www.medworm.com/index.php?rid=5578388&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22224977%26dopt%3DAbstract Authors: Giorgi G, Avalle L, Brignone M, Piana M, Caviglia G Abstract In cryosurgery operations, tumoural cells are killed by means of a freezing procedure realised with the insertion of cryoprobes in the diseased tissue. Cryosurgery planning aims at establishing the best values for operation parameters like number and position of the probes or temperature and duration of the freezing process. Here, we present an application of ant colony optimisation (ACO) to cryosurgery planning, whereby the ACO cost function is computed by numerically solving several direct Stefan problems in biological tissues. The method is validated in the case of a 2D phantom of a prostate cross section. PMID: 22224977 [PubMed - as supplied by publisher] (Source: Computer Methods in Biomechanics and Biom... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5578388 Fri, 06 Jan 2012 05:00:00 +0100 5578388 http://www.medworm.com/index.php?rid=5578387&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22225415%26dopt%3DAbstract Authors: Braga IU, Rocha DN, Utsch RL, Las Casas EB, Andrade RM, Jorge RN, Braga RU Abstract This paper presents a method for prediction of forces and displacements in the expansion screw of a modified mandibular Schwarz appliance and the contact pressure distributions on the mucosa during malocclusions treatment. A 3D finite element biomechanical model of the complete mandible-mucosa-apparatus set was built using computerised tomographic images of a patient's mandible and constructive solid geometry by computer software. An iterative procedure was developed to handle a boundary condition that takes into account the mandibular asymmetries. The results showed asymmetries in the contact pressure distributions that indicated with precision the patient's malocclusion diagnosis. In vivo... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5578387 Fri, 06 Jan 2012 05:00:00 +0100 5578387 http://www.medworm.com/index.php?rid=5578386&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22225468%26dopt%3DAbstract This article describes a method that allows estimating, with the 2D version of the direct linear transformation (DLT), the actual 2D coordinates of a point when the latter is not strictly in the calibration plane. Markers placed in vertical line, above, below and in the centre of a horizontal calibration plane were filmed by a moving camera. Without correction, strong errors (up to 64.5%) were noticed for markers out of the calibration plane. After correction, calculated coordinates were consistent with actual values (error < 0.55%). The method was then applied to slip distance measurement, using a marker fixed on the hoof of a horse trotting on a calibrated track while being followed with a camera. The correction effect represented 6.6% of slip distance. Combined with the 2D-DLT tran... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5578386 Fri, 06 Jan 2012 05:00:00 +0100 5578386 http://www.medworm.com/index.php?rid=5578385&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22225500%26dopt%3DAbstract Authors: Chang CW, Kuo LC, Jou IM, Su FC, Sun YN Abstract It is challenging to measure the finger's kinematics of underlying bones in vivo. This paper presents a new method of finger kinematics measurement, using a geometric finger model and several markers deliberately stuck on skin surface. Using a multiple-view camera system, the optimal motion parameters of finger model were estimated using the proposed mixture-prior particle filtering. This prior, consisting of model and marker information, avoids generating improper particles for achieving near real-time performance. This method was validated using a planar fluoroscopy system that worked simultaneously with photographic system. Ten male subjects with asymptomatic hands were investigated in experiments. The results showed that... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5578385 Fri, 06 Jan 2012 05:00:00 +0100 5578385 http://www.medworm.com/index.php?rid=5578384&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22225515%26dopt%3DAbstract Authors: Sauer RA, Holl M Abstract This paper presents a detailed finite element analysis of the adhesion of a gecko spatula. The gecko spatulae form the tips of the gecko foot hairs that transfer the adhesional and frictional forces between substrate and foot. The analysis is based on a parameterised description of the 3D geometry of the spatula that only requires 12 parameters. The adhesion is described by a nonlinear computational contact formulation that accounts for the van der Waals interaction between spatula and substrate. The spatula adhesion model is implemented using an enriched contact finite element formulation recently developed by the first author. The finite element model is then used to simulate the peeling behaviour of the gecko spatula under applied vertical and ... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5578384 Fri, 06 Jan 2012 05:00:00 +0100 5578384 http://www.medworm.com/index.php?rid=5578383&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22225543%26dopt%3DAbstract This study aimed to develop and validate a finite element (FE) model of a human clavicle which can predict the structural response and bone fractures under both axial compression and anterior-posterior three-point bending loads. Quasi-static non-injurious axial compression and three-point bending tests were first conducted on a male clavicle followed by a dynamic three-point bending test to fracture. Then, two types of FE models of the clavicle were developed using bone material properties which were set to vary with the computed tomography image density of the bone. A volumetric solid FE model comprised solely of hexahedral elements was first developed. A solid-shell FE model was then created which modelled the trabecular bone as hexahedral elements and the cortical bone as quadrilateral ... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5578383 Fri, 06 Jan 2012 05:00:00 +0100 5578383 http://www.medworm.com/index.php?rid=5578379&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22229516%26dopt%3DAbstract Authors: Evans S, Avril S PMID: 22229516 [PubMed - in process] (Source: Computer Methods in Biomechanics and Biomedical Engineering) Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5578379 Sun, 01 Jan 2012 05:00:00 +0100 5578379 http://www.medworm.com/index.php?rid=5535116&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22185521%26dopt%3DAbstract Authors: Post A, Oeur A, Hoshizaki B, Gilchrist MD Abstract Ice hockey is a contact sport which has a high incidence of brain injury. The current methods of evaluating protective devices use peak resultant linear acceleration as their pass/fail criteria, which are not fully representative of brain injuries as a whole. The purpose of this study was to examine how the linear and angular acceleration loading curves from a helmeted impact influence currently used brain deformation injury metrics. A helmeted Hybrid III headform was impacted in five centric and non-centric impact sites to elicit linear and angular acceleration responses. These responses were examined through the use of a brain model. The results indicated that when the helmet is examined using peak resultant linear accel... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5535116 Wed, 21 Dec 2011 05:00:00 +0100 5535116 http://www.medworm.com/index.php?rid=5535115&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22185582%26dopt%3DAbstract This study investigates FE mesh design for blast modelling using a sphere in a closed-ended shock tube meshed with varying element sizes using both tetrahedral and hexahedral elements. FSI was consistent for sphere-to-fluid element ratios between 0.25 and 4, and acceleration response was similar for both element types (R (2) = 0.997). Tetrahedral elements were found to become increasingly volatile following shock loading, causing higher pressures and stresses than predicted with the hexahedral elements. Deviatoric stress response was dependent on the sphere mesh size (p < 0.001), while the pressure response was dependent on the shock tube mesh size (p < 0.001). The results of this study highlight the necessity for mesh sensitivity analysis in blast models. PMID: 22185582 [P... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5535115 Wed, 21 Dec 2011 05:00:00 +0100 5535115 http://www.medworm.com/index.php?rid=5535114&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22185614%26dopt%3DAbstract Authors: Dimakopoulos Y, Bogaerds AC, Anderson PD, Hulsen MA, Baaijens FP Abstract We study the nonlinear interaction of an aortic heart valve, composed of hyperelastic corrugated leaflets of finite density attached to a stented vessel under physiological flow conditions. In our numerical simulations, we use a 2D idealised representation of this arrangement. Blood flow is caused by a time-varying pressure gradient that mimics that of the aortic valve and corresponds to a peak Reynolds number equal to 4050. Here, we fully account for the shear-thinning behaviour of the blood and large deformations and contact between the leaflets by solving the momentum and mass balances for blood and leaflets. The mixed finite element/Galerkin method along with linear discontinuous Lagrange multipl... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5535114 Wed, 21 Dec 2011 05:00:00 +0100 5535114 http://www.medworm.com/index.php?rid=5535113&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22185643%26dopt%3DAbstract Conclusions. The adjustment of the location of the anastomosis of the LVAD outflow cannula as well as its angle of incidence plays a significant role in the level of thromboembolisms. By proper adjustment in this CFD study of a synthetic model of an aortic arch bed, we found that nearly a 50% reduction in cerebral embolism could be achieved for a configuration consisting of a shallow angle of implantation over a baseline normal incidence of the LVAD cannula. Within the limitations of our model, we have established that the LVAD implantation geometry is an important factor and should be taken into consideration when implanting an LVAD. It is possible that other parameters such as distance of the LVAD outflow cannula to the root of the IA could affect the thrombi embolisation probabilities. ... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5535113 Wed, 21 Dec 2011 05:00:00 +0100 5535113 http://www.medworm.com/index.php?rid=5535112&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22185661%26dopt%3DAbstract Authors: Wang CW Abstract Tissue microarrays (TMAs) are an effective tool for high-throughput molecular analysis of tissues to help identify new diagnostic and prognostic markers and targets in human cancers. We have developed a fully automated method for rapid, continuous and quantitative analysis of TMAs based on immunohistochemistry. The method deals with complex and varying tissue architectures, segments tumour cells from normal cells, conducts cell compartmentalisation, identifies nuclei and cytoplasm and produces three different continuous measurements of marker expression levels within tumour cell nuclei, tumour cell cytoplasm and total tumour cell protein expression. We have demonstrated this method using three independent protein markers (BAK, BAX and a novel biomarker, na... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5535112 Wed, 21 Dec 2011 05:00:00 +0100 5535112 http://www.medworm.com/index.php?rid=5535118&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22185087%26dopt%3DAbstract In this study, a paediatric bed fall computer simulation model was developed and validated. The simulation was created using Mathematical Dynamic Modeling(®) software with a child restraint air bag interaction (CRABI) 12-month-old anthropomorphic test device (ATD) representing the fall victim. The model was validated using data from physical fall experiments of the same scenario with an instrumented CRABI ATD. Validation was conducted using both observational and statistical comparisons. Future parametric sensitivity studies using this model will lead to an improved understanding of relationships between child (fall victim) parameters, fall environment parameters and injury potential. PMID: 22185087 [PubMed - as supplied by publisher] (Source: Computer Methods in Biomechanics and Biom... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5535118 Tue, 20 Dec 2011 05:00:00 +0100 5535118 http://www.medworm.com/index.php?rid=5535117&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22185480%26dopt%3DAbstract The objective of this study was to map a template block structure, common to multiblock meshing techniques, to a subject-specific surface. The rationale is that the blocks are considerably less refined and may be readily edited after mapping, thereby yielding a mesh of high quality in less time than mapping the mesh itself. In this paper, the versatility and robustness of the method was verified by processing four data-sets. The method was found to be robust enough to cope with the variability of bony surface size, spatial position and geometry, producing building block structures (BBSs) that generated meshes comparable to those produced using BBSs that were created manually. PMID: 22185480 [PubMed - as supplied by publisher] (Source: Computer Methods in Biomechanics and Biomedical Eng... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5535117 Tue, 20 Dec 2011 05:00:00 +0100 5535117 http://www.medworm.com/index.php?rid=5513600&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22148924%26dopt%3DAbstract In this study, results indicate a good agreement of D between experimental values and numerical results. PMID: 22148924 [PubMed - as supplied by publisher] (Source: Computer Methods in Biomechanics and Biomedical Engineering) Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5513600 Thu, 08 Dec 2011 05:00:00 +0100 5513600 http://www.medworm.com/index.php?rid=5513599&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22148959%26dopt%3DAbstract Authors: Huang YC, Guo LY, Tsai CY, Su FC Abstract It has been suggested that minimisation of energy cost is one of the primary determinants of wheelchair designs. Wheel camber is one important parameter related to wheelchair design and its angle may affect usability during manual propulsion. However, there is little available literature addressing the effect of wheel camber on the mechanical energy or power flow involved in manual wheelchair propulsion. Twelve normal subjects (mean age, 22.3 years; SD, 1.6 years) participated in this study. A video-tracking system and an instrumented wheel were used to collect 3D kinematic and kinetic data. Wheel camber of 0° and 15° was chosen to examine the difference between mechanical power and power flow of the upper extremity during manual... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5513599 Thu, 08 Dec 2011 05:00:00 +0100 5513599 http://www.medworm.com/index.php?rid=5513598&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22149002%26dopt%3DAbstract Authors: Clarke SG, Phillips AT, Bull AM Abstract To enable large-scale multi-factorial finite element (FE) studies, the FE models used must be as computationally efficient as is feasible, while maintaining a suitable level of definition. The present study seeks to find an optimum level of model complexity for use in such large-scale studies by investigating which model attributes are most influential over the chosen model outputs of principal stress and strain in the intact acetabulum. A multi-factorial sensitivity study was carried out using 128 FE models, representing combinations of the following variables: bone stiffness distribution, imposed muscle loading, boundary condition location, hip joint contact conditions and patient's bone anatomy. The relative sensitivity of each i... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5513598 Thu, 08 Dec 2011 05:00:00 +0100 5513598 http://www.medworm.com/index.php?rid=5513597&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22149043%26dopt%3DAbstract Authors: Brown CJ, Sinclair RA, Day A, Hess B, Procter P Abstract This paper presents a finite element (FE) model to identify parameters that affect the performance of an improved cancellous bone screw fixation technique, and hence potentially improve fracture treatment. In cancellous bone of low apparent density, it can be difficult to achieve adequate screw fixation and hence provide stable fracture fixation that enables bone healing. Data from predictive FE models indicate that cements can have a significant potential to improve screw holding power in cancellous bone. These FE models are used to demonstrate the key parameters that determine pull-out strength in a variety of screw, bone and cement set-ups, and to compare the effectiveness of different configurations. The paper co... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5513597 Thu, 08 Dec 2011 05:00:00 +0100 5513597 http://www.medworm.com/index.php?rid=5513596&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22149087%26dopt%3DAbstract Authors: Eskofier BM, Federolf P, Kugler PF, Nigg BM Abstract The classification of gait patterns has great potential as a diagnostic tool, for example, for the diagnosis of injury or to identify at-risk gait in the elderly. The purpose of the paper is to present a method for classifying group differences in gait pattern by using the complete spatial and temporal information of the segment motion quantified by the markers. The classification rates that are obtained are compared with previous studies using conventional classification features. For our analysis, 37 three-dimensional marker trajectories were collected from each of our 24 young and 24 elderly female subjects while they were walking on a treadmill. Principal component analysis was carried out on these trajectories to ... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5513596 Thu, 08 Dec 2011 05:00:00 +0100 5513596 http://www.medworm.com/index.php?rid=5513595&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22149119%26dopt%3DAbstract Authors: Schmid H, Grytsan A, Poshtan E, Watton PN, Itskov M Abstract Experimental and computational studies suggest a substantial variation in the mechanical responses and collagen fibre orientations of the two structurally important layers of the arterial wall. Some observe the adventitia to be an order of magnitude stiffer than the media whilst others claim the opposite. Furthermore, studies show that molecular metabolisms may differ substantially in each layer. Following a literature review that juxtaposes the differing layer-specific results we create a range of different hypothetical arteries: (1) with different elastic responses, (2) different fibre orientations, and (3) different metabolic activities during adaptation. We use a finite element model to investigate the effect... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5513595 Thu, 08 Dec 2011 05:00:00 +0100 5513595 http://www.medworm.com/index.php?rid=5513594&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22149159%26dopt%3DAbstract This study tried to compensate for systematic stimulation control and other problems that occurred with previously developed tactile stimulators. The newly developed system consists of three units: a control unit, a drive unit and a vibrator. Since the developed system is a small, lightweight, simple structure with low electrical consumption, a maximum of 35 stimulation channels and various visual and auditory stimulation combinations without delay time, the previous systematic problem is corrected in this study. The system was designed to stimulate any part of the body including the fingers. Since the developed tactile stimulator used E-Prime software, which is widely used in the study of visual and auditory senses, the stimulator is expected to be highly practical due to a diverse combin... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5513594 Thu, 08 Dec 2011 05:00:00 +0100 5513594 http://www.medworm.com/index.php?rid=5513593&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22149183%26dopt%3DAbstract In this study, we present a framework for accurate determination of the wall shear stress (WSS) in a mildly stenosed carotid artery after the implantation of a stent, resembling the commercially available Acculink (Abbott Laboratories, Abbott Park, Illinois, USA). Starting from angiographic CT images of the vessel lumen and a micro-CT scan of the stent, a finite element analysis is carried out in order to deploy the stent in the vessel, reproducing CAS in silico. Then, based on the post-stenting anatomy, the vessel is perfused using a set of boundary conditions: total pressure is applied at the inlet, and impedances that are assumed to be insensitive to the presence of the stent are imposed at the outlets. Evaluation of the CAS outcome from a geometrical and haemodynamic perspective shows ... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5513593 Thu, 08 Dec 2011 05:00:00 +0100 5513593 http://www.medworm.com/index.php?rid=5513592&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22149220%26dopt%3DAbstract Authors: Erdem I, Truumees E, van der Meulen MC Abstract Three-dimensional finite element models of the thoracolumbar junction (T12-L2) and isolated L1 vertebra were developed to investigate the role of material properties and loading conditions on vertebral stresses and strains to predict fracture risk. The geometry of the vertebrae was obtained from computed tomography images. The isolated vertebra model included an L1 vertebra loaded through polymethylmethacrylate plates located at the top and bottom of the vertebra, and the segment model included T12 to L2 vertebrae and seven ligaments, fibrous intervertebral discs and facet joints. Each model was examined with both homogeneous and spatially varying bone tissue properties. Stresses and strains were compared for uniform compress... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5513592 Thu, 08 Dec 2011 05:00:00 +0100 5513592 http://www.medworm.com/index.php?rid=5513591&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22149289%26dopt%3DAbstract Authors: Mao H, Gao H, Cao L, Genthikatti VV, Yang KH Abstract The finite element (FE) method is a powerful tool to study brain injury that remains to be a critical health concern. Subject/patient-specific FE brain models have the potential to accurately predict a specific subject/patient's brain responses during computer-assisted surgery or to design subject-specific helmets to prevent brain injury. Unfortunately, efforts required in the development of high-quality hexahedral FE meshes for brain, which consists of complex intracranial surfaces and varying internal structures, are daunting. Using multi-block techniques, an efficient meshing process to develop all-hexahedral FE brain models for an adult and a paediatric brain (3-year old) was demonstrated in this study. Furthermore,... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5513591 Thu, 08 Dec 2011 05:00:00 +0100 5513591 http://www.medworm.com/index.php?rid=5513590&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22149355%26dopt%3DAbstract The objective of the current study was to demonstrate the utility of a new integrative ambulatory measurement (IAM) framework by developing and evaluating an individual calibration function in fall detection application. Ten healthy elderly persons were involved in a laboratory study and tested in a protocol comprising various types of activities of daily living and slip-induced backward falls. Inertial measurement units attached to the trunk and thigh segments were used to measure trunk angular kinematics and thigh accelerations. The effect of individual calibration was evaluated with previously developed fall detection algorithm. The results indicated that with individual calibration, the fall detection performance achieved approximately the same level of sensitivity (100% vs. 100%) and ... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5513590 Thu, 08 Dec 2011 05:00:00 +0100 5513590 http://www.medworm.com/index.php?rid=5513589&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22149414%26dopt%3DAbstract Authors: Helwig P, Hindenlang U, Hirschmüller A, Konstantinidis L, Südkamp N, Schneider R Abstract In order to evaluate stabilisation systems in trochanteric femoral fractures with finite element (FE) analysis, a realistic model is required. For this purpose, a new model of a femur with all the relevant muscles and the hip capsule ligaments is set up. The pelvic and tibial bones are modelled as rigid bodies so as to take all the muscles attached to the femur into account. Fracture zones in the proximal femur are defined. Following the modelling of the geometry, the isotropic material behaviour and the load application, a numerical calculation of the femur is carried out. The static iterated FE simulation shows good agreement with in vivo data for the one-leg-stance phase during w... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5513589 Thu, 08 Dec 2011 05:00:00 +0100 5513589 http://www.medworm.com/index.php?rid=5513588&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22149471%26dopt%3DAbstract This study compared Fung's quasi-linear viscoelastic (QLV) model with a stretched-exponential model of cartilage stress relaxation and examined each of these models both alone and in combination with a fluid-flow model in unconfined compression. Cartilage explants were harvested from bovine calf patellofemoral joints and equilibrated in tissue culture for 5 days before stress-relaxation testing in unconfined compression at 5% nominal strain. The stretched exponential models fit as well as the QLV models. Furthermore, the average stretched exponential relaxation time determined by this model lies within the range of experimentally measured relaxation times for extracted proteoglycan aggregates, consistent with the hypothesis that the stretched exponential model represents polymeric mechanis... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5513588 Thu, 08 Dec 2011 05:00:00 +0100 5513588 http://www.medworm.com/index.php?rid=5493381&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22136230%26dopt%3DAbstract Authors: Delalleau A, Josse G, Lagarde JM Abstract This paper presents a procedure for characterising the mechanical properties of skin using stochastic inverse identification. It is based on the minimisation of a cost function relative to the comparison between experimental suction experiments and their corresponding finite element models. Two different models are compared: a classical single-layer approach and a dual-layer medium which account for both the dermis and the hypodermis. Finite element results are used to construct the pre-optimisation database which is required for the inverse analysis. To compare the calculations, the entire identification is based on a dual-parameter optimisation procedure: for the single-layer approach a quadratic hyperelastic constitutive equatio... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5493381 Mon, 05 Dec 2011 05:00:00 +0100 5493381 http://www.medworm.com/index.php?rid=5493382&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22136186%26dopt%3DAbstract Authors: Petrella AJ, Armstrong JR, Laz PJ, Rullkoetter PJ Abstract Wear testing of polyethylene in total joint replacements is common and required for any new device. Computational wear modelling has obvious utility in this context as it can be conducted with much greater economy than physical testing. Archard's law has become the accepted standard for wear simulation in total joints but it does not account for cross-shear, which is known to increase wear significantly relative to unidirectional sliding. The purpose of this study was to develop a robust cross-shear model applicable to any interface geometry under any kinematic conditions. The proposed metric, x (*), is distinguished from existing cross-shear models by the fact that it measures cross-path motion incrementally throu... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5493382 Fri, 02 Dec 2011 05:00:00 +0100 5493382 http://www.medworm.com/index.php?rid=5493383&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22128759%26dopt%3DAbstract Authors: Chamoret D, Roth S, Feng ZQ, Yan XT, Gomes S, Peyraut F Abstract A deeper understanding of biomechanical behaviour of human hands becomes fundamental for any human hand-operated activities. The integration of biomechanical knowledge of human hands into product design process starts to play an increasingly important role in developing an ergonomic product-to-user interface for products and systems requiring high level of comfortable and responsive interactions. Generation of such precise and dynamic models can provide scientific evaluation tools to support product and system development through simulation. This type of support is urgently required in many applications such as hand skill training for surgical operations, ergonomic study of a product or system developed and s... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5493383 Wed, 30 Nov 2011 05:00:00 +0100 5493383 http://www.medworm.com/index.php?rid=5421159&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22085241%26dopt%3DAbstract Authors: Wang S, Ding G, Zhang Y, Yang X Abstract Endovascular stents are being commonly used to treat cerebral wide-necked aneurysms recently. The effect of a stent placed in the parent artery is not only to protect the parent artery from occlusion, due to extension of coils and thrombosis, but also to act as flow diverter to vary the haemodynamics in the aneurysm. In this article, two idealised cerebral wide-necked aneurysms were created, one was sidewall aneurysm with curved parent vessel and the other was terminal aneurysm with the bifurcated parent vessel. The plexiglass models of the two aneurysms were 'treated' with commercial porous intravascular stents. The stented physical models were scanned by Micro-CT and the numerical models of the two idealised cerebral wide-necked a... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5421159 Tue, 01 Nov 2011 04:00:00 +0100 5421159 http://www.medworm.com/index.php?rid=5297631&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21978095%26dopt%3DAbstract Authors: Joshi D, Mishra A, Anand S Abstract A probabilistic modelling is presented to detect mental activity from gait signature recorded from healthy subjects. The proposed scheme is based on principal component analysis with reduced feature dimension followed by a naïve Gaussian Bayes classifier. The leave-one-out cross-validation shows the detection accuracy of 94% with specificity and sensitivity of 96% and 98.3%, respectively. The research has a potential application in the prevention of elderly risk falls, lie detection and rehabilitation among Parkinson's patients. PMID: 21978095 [PubMed - as supplied by publisher] (Source: Computer Methods in Biomechanics and Biomedical Engineering) Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5297631 Thu, 06 Oct 2011 04:00:00 +0100 5297631 http://www.medworm.com/index.php?rid=5297641&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21970322%26dopt%3DAbstract In this study, we show that strain patterns similar to those observed during biological experiments can be reproduced by properly combining the two phenomena. In addition, we use a novel technique to parameterise the embryo geometry by solving two Laplace problems with specific boundary conditions. We apply the method to two morphogenetic movements: ventral furrow invagination and germ band extension. The matching between our results and the observed experimental deformations confirms that diffusion-reaction of morphogens can actually be controlling large morphogenetic movements. PMID: 21970322 [PubMed - as supplied by publisher] (Source: Computer Methods in Biomechanics and Biomedical Engineering) Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5297641 Tue, 04 Oct 2011 04:00:00 +0100 5297641 http://www.medworm.com/index.php?rid=5297640&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21970360%26dopt%3DAbstract Authors: Acharya UR, Faust O, Sree SV, Ghista DN, Dua S, Joseph P, Ahamed VI, Janarthanan N, Tamura T Abstract Electrocardiogram (ECG) signals are difficult to interpret, and clinicians must undertake a long training process to learn to diagnose diabetes from subtle abnormalities in these signals. To facilitate these diagnoses, we have developed a technique based on the heart rate variability signal obtained from ECG signals. This technique uses digital signal processing methods and, therefore, automates the detection of diabetes from ECG signals. In this paper, we describe the signal processing techniques that extract features from heart rate (HR) signals and present an analysis procedure that uses these features to diagnose diabetes. Through statistical analysis, we have identifi... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5297640 Tue, 04 Oct 2011 04:00:00 +0100 5297640 http://www.medworm.com/index.php?rid=5297639&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21970401%26dopt%3DAbstract Authors: Coulongeat F, Jarrar MS, Thollon L, Serre T Abstract This paper analyses the geometry of intra-thoracic organs from computed tomography (CT) scans performed on 20 children aged from 4 months to 16 years. The aim is to find the most reliable measurements to characterise the growth of heart and lungs from CT data. Standard measurements available on chest radiographies are compared with original measurements only available on CT scans. These measurements should characterise the growth of organs as well as the changes in their position relative to the thorax. Measurements were considered as functions of age. Quadratic regression models were fitted to the data. Goodness of fit of the models was then evaluated. Positions of organs relative to the thorax have a high variability c... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5297639 Tue, 04 Oct 2011 04:00:00 +0100 5297639 http://www.medworm.com/index.php?rid=5297638&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21970559%26dopt%3DAbstract Authors: Schwartz C, Leboeuf F, Rémy-Néris O, Brochard S, Lempereur M, Burdin V Abstract In biomechanical modelling and motion analysis, the use of personalised data such as bone geometry would provide more accurate and reliable results. However, there are still a limited number of tools used to measure the evolution of articular interactions. This paper proposes a coherence index to describe the articular status of contact surfaces during motion. The index relies on a robust estimation of the evolution of surfacic interactions between the joint surfaces. The index is first compared to distance maps on simulated motions. It is then used to compare two motion capture protocols (two different localisations of the markers for scapula tracking). The results show that the index detect... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5297638 Tue, 04 Oct 2011 04:00:00 +0100 5297638 http://www.medworm.com/index.php?rid=5297637&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21970595%26dopt%3DAbstract Authors: Chen MQ, Wong J, Kuhl E, Giovangrandi L, Kovacs GT Abstract Cardiac arrhythmias are disturbances of the electrical conduction pattern in the heart with severe clinical implications. The damage of existing cells or the transplantation of foreign cells may disturb functional conduction pathways and may increase the risk of arrhythmias. Although these conduction disturbances are easily accessible with the human eye, there is no algorithmic method to extract quantitative features that quickly portray the conduction pattern. Here, we show that co-occurrence analysis, a well-established method for feature recognition in texture analysis, provides insightful quantitative information about the uniformity and the homogeneity of an excitation wave. As a first proof-of-principle, we ... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5297637 Tue, 04 Oct 2011 04:00:00 +0100 5297637 http://www.medworm.com/index.php?rid=5297636&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21970618%26dopt%3DAbstract In this study, we utilise the concept of synergy formation as a simplifying control strategy to find the muscle recruitment based on summation of identified muscle synergies to balance the biomechanical demands (biaxial external torque) during an isometric shoulder task. A numerical optimisation-based shoulder model was used to obtain muscle activation levels when a biaxial external isometric torque is imposed at the shoulder glenohumeral joint. In the numerical simulations, 12 different shoulder torque vectors in the transverse plane are considered. For each selected direction for the torque vector, the resulting muscle activation data are calculated. The predicted muscle activation data are used for grouping muscles in some fixed element synergies by the non-negative matrix factorisation... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5297636 Tue, 04 Oct 2011 04:00:00 +0100 5297636 http://www.medworm.com/index.php?rid=5297635&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21970670%26dopt%3DAbstract This study aims to develop a computational mechanics approach to evaluate microscale fracture mechanisms in bone. In this study, finite element models based on actual human cortical bone images that allow for arbitrary crack growth were utilised to determine the crack propagation behaviour. The simulations varied the cement line and osteon strength and fracture toughness in different bone microstructures to assess the crack propagation trajectory, stress-strain relationship and nonlinear strain energy density. The findings of this study provide additional insight into the individual influence of microstructural features and their properties on crack growth behaviour in bone using a computational approach. PMID: 21970670 [PubMed - as supplied by publisher] (Source: Computer Methods in B... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5297635 Tue, 04 Oct 2011 04:00:00 +0100 5297635 http://www.medworm.com/index.php?rid=5297634&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21970697%26dopt%3DAbstract Authors: Galbusera F, Mietsch A, Schmidt H, Wilke HJ, Neidlinger-Wilke C Abstract Degeneration of the intervertebral disc may be initiated and supported by impairment of the nutrition processes of the disc cells. The effects of degenerative changes on cell nutrition are, however, only partially understood. In this work, a finite volume model was used to investigate the effect of endplate calcification, water loss, reduction of disc height and cyclic mechanical loading on the sustainability of the disc cell population. Oxygen, lactate and glucose diffusion, production and consumption were modelled with non-linear coupled partial differential equations. Oxygen and glucose consumption and lactate production were expressed as a function of local oxygen concentration, pH and cell densit... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5297634 Tue, 04 Oct 2011 04:00:00 +0100 5297634 http://www.medworm.com/index.php?rid=5297633&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21970726%26dopt%3DAbstract Authors: Li L, Qian X, Yan S, Lei J, Wang X, Zhang H, Liu Z Abstract Soft tissues are anisotropic materials yet a majority of mechanical property tests have been uniaxial, which often failed to recapitulate the tensile response in other directions. This paper aims to study the feasibility of determining material parameters of anisotropic tissues by uniaxial extension with a minimal loss of anisotropic information. We assumed that by preselecting a certain constitutive model, we could give the constitutive parameters based on uniaxial extension data from orthogonal strip samples. In our study, the Holzapfel-Weizsäcker type strain energy density function (H-W model) was used to determine the material parameters of arterial walls from two fresh donation bodies. The key points we appl... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5297633 Tue, 04 Oct 2011 04:00:00 +0100 5297633 http://www.medworm.com/index.php?rid=5297632&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21970765%26dopt%3DAbstract Authors: Guess TM, Liu H, Bhashyam S, Thiagarajan G Abstract Combining musculoskeletal simulations with anatomical joint models capable of predicting cartilage contact mechanics would provide a valuable tool for studying the relationships between muscle force and cartilage loading. As a step towards producing multibody musculoskeletal models that include representation of cartilage tissue mechanics, this research developed a subject-specific multibody knee model that represented the tibia plateau cartilage as discrete rigid bodies that interacted with the femur through deformable contacts. Parameters for the compliant contact law were derived using three methods: (1) simplified Hertzian contact theory, (2) simplified elastic foundation contact theory and (3) parameter optimisation ... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5297632 Tue, 04 Oct 2011 04:00:00 +0100 5297632 http://www.medworm.com/index.php?rid=5281168&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20924859%26dopt%3DAbstract Authors: Senanayake C, Senanayake SM Abstract In this paper, a gait event detection algorithm is presented that uses computer intelligence (fuzzy logic) to identify seven gait phases in walking gait. Two inertial measurement units and four force-sensitive resistors were used to obtain knee angle and foot pressure patterns, respectively. Fuzzy logic is used to address the complexity in distinguishing gait phases based on discrete events. A novel application of the seven-dimensional vector analysis method to estimate the amount of abnormalities detected was also investigated based on the two gait parameters. Experiments were carried out to validate the application of the two proposed algorithms to provide accurate feedback in rehabilitation. The algorithm responses were tested for tw... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5281168 Sat, 01 Oct 2011 04:00:00 +0100 5281168 http://www.medworm.com/index.php?rid=5281167&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21347910%26dopt%3DAbstract Authors: Dinarvand S Abstract In this article, the problem of laminar, isothermal, incompressible and viscous flow in a rectangular domain bounded by two moving porous walls, which enable the fluid to enter or exit during successive expansions or contractions, is investigated. The governing non-linear equations and their associated boundary conditions are transformed into a highly non-linear ordinary differential equation. The series solution of the problem is obtained by utilising the homotopy perturbation method. Graphical results are presented to investigate the influence of the non-dimensional wall dilation rate and seepage Reynolds number (Re) on the velocity, normal pressure distribution and wall shear stress. Since the transport of biological fluids through contracting or ex... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5281167 Sat, 01 Oct 2011 04:00:00 +0100 5281167 http://www.medworm.com/index.php?rid=5260721&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21933037%26dopt%3DAbstract Authors: El Ouaaid Z, Shirazi-Adl A, Arjmand N, Plamondon A Abstract To circumvent the existing shortcoming of optimisation algorithms in trunk biomechanical models, both agonist and antagonist trunk muscle stresses to different powers are introduced in a novel objective function to evaluate the role of abdominal muscles in trunk stability and spine compression. This coupled objective function is introduced in our kinematics-driven finite element model to estimate muscle forces and to identify the role of abdominal muscles in upright standing while lifting symmetrically a weight at different heights. Predictive equations for the compression and buckling forces are developed. Results are also compared with the conventional objective function that neglects abdominal muscle forces. An... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5260721 Wed, 21 Sep 2011 04:00:00 +0100 5260721 http://www.medworm.com/index.php?rid=5260722&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21923559%26dopt%3DAbstract Authors: Ciocca L, Fantini M, De Crescenzio F, Corinaldesi G, Scotti R Abstract The protocol presented here is intended to minimise the intervention in bone reconstruction surgery when severe atrophy or deformity is present in the maxillary arches. A patient underwent augmentation of an atrophic maxillary arch using titanium mesh and particulate autogenous plus bovine demineralised bone. After computed tomography data elaboration, computer-aided design and computer-aided machining were used to plan the augmentation of bone volume to improve the implant position needed to support the final dental prosthesis. The augmented maxilla was rapidly prototyped in plastic, and the titanium mesh was tested on this model before the surgical intervention. Then, the preformed titanium mesh was i... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5260722 Mon, 19 Sep 2011 04:00:00 +0100 5260722 http://www.medworm.com/index.php?rid=5231488&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21916674%26dopt%3DAbstract Authors: Hu Y, Shi L, Du D, Parameswaran S, He Z Abstract A numerical method of the left ventricle (LV) deformation, an elongation model, was put forth for the study of LV fluid mechanics in diastole. The LV elongated only along the apical axis, and the motion was controlled by the intraventricular flow rate. Two other LV models, a fixed control volume model and a dilation model, were also used for model comparison and the study of LV fluid mechanics. For clinical sphere indices (SIs, between 1.0 and 2.0), the three models showed little difference in pressure and velocity distributions along the apical axis at E-peak. The energy dissipation was lower at a larger SI in that the jet and vortex development was less limited by the LV cavity in the apical direction. LV deformation of ap... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5231488 Wed, 14 Sep 2011 04:00:00 +0100 5231488 http://www.medworm.com/index.php?rid=5231487&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21916675%26dopt%3DAbstract Authors: Kuznetsov AV Abstract The purpose of this paper was to develop an analytical solution describing retrograde transport of nerve growth factors (NGFs) from a target tissue to the neuron soma. The obtained solution is applied to describe two situations: (1) when all dynein motors are moving at a constant velocity and (2) when the dynein velocity distribution is described by a probability density function. The dynamics of NGF concentrations and fluxes is investigated. It is established that the magnitude of the diffusion flux forms a wave localised in space and propagating towards the neuron soma; the magnitude of this wave decreases as the wave propagates downstream. The dynein-driven flux of NGFs is demonstrated to be the main component in the NGF flux, which is shown to be ... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5231487 Wed, 14 Sep 2011 04:00:00 +0100 5231487 http://www.medworm.com/index.php?rid=5231486&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21916676%26dopt%3DAbstract Authors: Lee HP, Garlapati RR, Chong VF, Wang DY Abstract Partial inferior turbinectomy is typically performed on patients suffering from chronic nasal obstruction due to hypertrophy of inferior turbinates and is refractory to other more conservative treatments. The effects of the various options of incision performed on the inferior turbinate in terms of the resulting nasal airflow pattern are examined using computational fluid mechanics. The pressure drops across the severely blocked nose and healthy nose models were found to be 32.3 and 12.3?Pa, respectively, whereas the pressure drops across the nasal cavity following one-third turbinate resection, total turbinate resection and front-end resection were obtained as 5.8, 6.1 and 30.5?Pa correspondingly. Based on the total pressur... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5231486 Wed, 14 Sep 2011 04:00:00 +0100 5231486 http://www.medworm.com/index.php?rid=5231485&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21916677%26dopt%3DAbstract This study is based on the SiNuPrOs model that allows exchange of information between the different structural scales of cortical bone. It shows that more than the fluid, the collagen ? via its piezoelectric properties ? plays an essential role in the transmission of information between the macroscopic and nanoscopic scales. Moreover, this process allows us to explain various dysfunctions and even some diseases. PMID: 21916677 [PubMed - as supplied by publisher] (Source: Computer Methods in Biomechanics and Biomedical Engineering) Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5231485 Wed, 14 Sep 2011 04:00:00 +0100 5231485 http://www.medworm.com/index.php?rid=5231484&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21916678%26dopt%3DAbstract Authors: Liang F, Takagi S, Himeno R, Liu H Abstract A variety of methods have been proposed to noninvasively assess arterial stiffness using single or multiple oscillometric cuffs. A common pitfall of most of such methods is that the individual-specific accuracy of assessment is not clearly known due to an insufficient understanding of the relationships between the characteristics of cuff oscillometry and cardiovascular properties. To provide a tool for quantitatively investigating such relationships, we developed a computational model of the cardiovascular system coupled with an oscillometric cuff wrapped around the left upper arm. The model was first examined by simulating the inflation?deflation process of the cuff. The simulated results reasonably reproduced the well-establish... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5231484 Wed, 14 Sep 2011 04:00:00 +0100 5231484 http://www.medworm.com/index.php?rid=5219102&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21895556%26dopt%3DAbstract In conclusion, injuries resulting from the traumatic situations were more damaging to the integrity of the tooth and its associated hard-tissue structures. PMID: 21895556 [PubMed - as supplied by publisher] (Source: Computer Methods in Biomechanics and Biomedical Engineering) Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5219102 Wed, 07 Sep 2011 04:00:00 +0100 5219102 http://www.medworm.com/index.php?rid=5192992&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21878002%26dopt%3DAbstract This study shows that imposing muscle physiology as well as globally optimising performance is important to accurately calculate MT forces underlying gait. PMID: 21878002 [PubMed - as supplied by publisher] (Source: Computer Methods in Biomechanics and Biomedical Engineering) Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5192992 Tue, 30 Aug 2011 23:00:00 +0100 5192992 http://www.medworm.com/index.php?rid=5141526&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21827286%26dopt%3DAbstract Authors: Cui G, Shrestha R, Han K Abstract Many biological processes are performed by a group of proteins rather than by individual proteins. Proteins involved in the same biological process often form a densely connected sub-graph in a protein-protein interaction network. Therefore, finding a dense sub-graph provides useful information to predict the function or protein complex of uncharacterised proteins in the sub-graph. We developed a heuristic algorithm that finds functional modules in a protein-protein interaction network and visualises the modules. The algorithm has been implemented in a platform-independent, standalone program called ModuleSearch. In an interaction network of yeast proteins, ModuleSearch found 366 overlapping modules. Of the modules, 71% have a function sha... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5141526 Mon, 08 Aug 2011 23:00:00 +0100 5141526 http://www.medworm.com/index.php?rid=5103747&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21809938%26dopt%3DAbstract Authors: Dubuis L, Avril S, Debayle J, Badel P Elastic compression is recommended in prophylaxis and the treatment of venous disorder of the human leg. However, the mechanisms of compression are not completely understood and the response of internal tissues to the external pressure is partially unknown. To address this later issue, a 3D FE model of a human leg is developed. The geometry is derived from 3D CT scans. The FE model is made up of soft tissues and rigid bones. An inverse method is applied to identify the properties of soft tissues which are modelled as hyperelastic, near-incompressible, homogeneous and isotropic materials. The principle is to calibrate the constitutive properties using CT scans carried out with and without the presence of a compression sock. The deformed geo... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5103747 Mon, 01 Aug 2011 23:00:00 +0100 5103747 http://www.medworm.com/index.php?rid=5103746&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21809942%26dopt%3DAbstract In this study, the characterisation of a preliminary design of a new GDD is presented. This is activated by means of a diaphragm, which is actuated by conducting polymers. The valve can be manufactured employing microelectromechanical system technology by soft lithography. The characterisation process is performed by numerical simulation using the finite element method, considering the coupling between the fluid and the structure (diaphragm) obtaining the hydraulic resistance for several positions of the diaphragm. To analyse the hydraulic system of the microvalve implanted in a human eye, an equivalent circuit model was used. The parameters of the equivalent circuit model were obtained from numerical simulation. The hydraulic resistance of the designed GDD varies in the range of 13.08-0.3... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5103746 Mon, 01 Aug 2011 23:00:00 +0100 5103746 http://www.medworm.com/index.php?rid=5103745&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21809943%26dopt%3DAbstract Authors: Vahdati A, Wagner DR Most tissue-engineered cartilage constructs are more compliant than native articular cartilage (AC) and are poorly integrated to the surrounding tissue. To investigate the effect of an implanted tissue-engineered construct (TEC) with these inferior properties on the mechanical environment of both the engineered and adjacent native tissues, a finite element study was conducted. Biphasic swelling was used to model tibial cartilage and an implanted TEC with the material properties of either native tissue or a decreased elastic modulus and fixed charged density. Creep loading was applied with a rigid impermeable indenter that represented the femur. In comparison with an intact joint, compressive strains in the transplant, surface contact stress in the adjacent... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5103745 Mon, 01 Aug 2011 23:00:00 +0100 5103745 http://www.medworm.com/index.php?rid=5103744&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21809944%26dopt%3DAbstract Authors: Miki T, Wang X, Aoki T, Imai Y, Ishikawa T, Takase K, Yamaguchi T In this paper, we propose a novel patient-specific method of modelling pulmonary airflow using graphics processing unit (GPU) computation that can be applied in medical practice. To overcome the barriers imposed by computation speed, installation price and footprint to the application of computational fluid dynamics, we focused on GPU computation and the lattice Boltzmann method (LBM). The GPU computation and LBM are compatible due to the characteristics of the GPU. As the optimisation of data access is essential for the performance of the GPU computation, we developed an adaptive meshing method, in which an airway model is covered by isotropic subdomains consisting of a uniform Cartesian mesh. We found that 4(3... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5103744 Mon, 01 Aug 2011 23:00:00 +0100 5103744 http://www.medworm.com/index.php?rid=5103743&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21809945%26dopt%3DAbstract Authors: Vernerey FJ, Greenwald EC, Bryant SJ One critical component of engineering living tissue equivalents is the design scaffolds (often made of hydrogels) whose degradation kinetics can match that of matrix production by cells. However, cell-mediated enzymatic degradation of a hydrogel is a highly complex and nonlinear process that is challenging to comprehend based solely on experimental observations. To address this issue, this study presents a triphasic mixture model of the enzyme-hydrogel system, which consists of a solid polymer network, water and enzyme. On the basis mixture theory, the rubber elasticity theory and the Michaelis-Menton kinetics for degradation, the model naturally incorporates a strong coupling between gel mechanical properties, the kinetics of degradation a... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5103743 Mon, 01 Aug 2011 23:00:00 +0100 5103743 http://www.medworm.com/index.php?rid=5103757&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21797802%26dopt%3DAbstract The objective of this study was to create a parametric numerical finite element (FE) analysis to compare the effect of surgical techniques used for total TM joint replacement implantation on loading the TM joint on the other side. Our hypothesis is that for the optimal function of all total TM joint replacements used in clinical practice it is crucial to devise a minimally invasive surgical technique, whereby there is minimum resection of masticatory muscles. This factor is more important than the design of the usually used total TM joint replacements. The extent of muscle resection influences the mechanical loading of the whole system. In the parametric FE analyses, the magnitude of the TM joint loading was compared for four different ranges of muscle resections during bite, using an anat... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5103757 Sun, 31 Jul 2011 23:00:00 +0100 5103757 http://www.medworm.com/index.php?rid=5103754&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21806410%26dopt%3DAbstract Authors: Fernandes PC, Fernandes PR, Folgado JO, Levy Melancia J This paper presents a biomechanical analysis of the cervical C5-C6 functional spine unit before and after the anterior cervical discectomy and fusion. The aim of this work is to study the influence of the medical procedure and its instrumentation on range of motion and stress distribution. First, a three-dimensional finite element model of the lower cervical spine is obtained from computed tomography images using a pipeline of image processing, geometric modelling and mesh generation software. Then, a finite element study of parameters' influence on motion and a stress analysis at physiological and different post-operative scenarios were made for the basic movements of the cervical spine. It was confirmed that the results... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5103754 Sun, 31 Jul 2011 23:00:00 +0100 5103754 http://www.medworm.com/index.php?rid=5103753&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21806411%26dopt%3DAbstract Authors: Zhu Z, Li G Fluoroscopic image technique, using either a single image or dual images, has been widely applied to measure in vivo human knee joint kinematics. However, few studies have compared the advantages of using single and dual fluoroscopic images. Furthermore, due to the size limitation of the image intensifiers, it is possible that only a portion of the knee joint could be captured by the fluoroscopy during dynamic knee joint motion. In this paper, we presented a systematic evaluation of an automatic 2D-3D image matching method in reproducing spatial knee joint positions using either single or dual fluoroscopic image techniques. The data indicated that for the femur and tibia, their spatial positions could be determined with an accuracy and precision less than 0.2 mm i... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5103753 Sun, 31 Jul 2011 23:00:00 +0100 5103753 http://www.medworm.com/index.php?rid=5103752&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21806412%26dopt%3DAbstract Authors: Ganpule S, Gu L, Alai A, Chandra N The effectiveness of helmets in extenuating the primary shock waves generated by the explosions of improvised explosive devices is not clearly understood. In this work, the role of helmet on the overpressurisation and impulse experienced by the head were examined. The shock wave-head interactions were studied under three different cases: (i) unprotected head, (ii) head with helmet but with varying head-helmet gaps and (iii) head covered with helmet and tightly fitting foam pads. The intensification effect was discussed by examining the shock wave flow pattern and verified with experiments. A helmet with a better protection against shock wave is suggested. PMID: 21806412 [PubMed - as supplied by publisher] (Source: Computer Methods in Biom... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5103752 Sun, 31 Jul 2011 23:00:00 +0100 5103752 http://www.medworm.com/index.php?rid=5103751&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21806413%26dopt%3DAbstract Authors: Lempereur M, Brochard S, Rémy-Néris O Functional methods can be used to determine the centre of rotation (CoR) of a ball-and-socket joint. The algorithms are used to locate rather the hip joint centre than the glenohumeral joint centre. The choice of the most suitable method depends especially on the intra- and inter-session repeatability of these methods. This paper aims at evaluating the intra- and inter-session repeatability of functional methods with which the glenohumeral joint rotation centre (GHRC) can be estimated in vivo. It also estimates the most suitable amplitude of functional movements. Five functional methods were tested: the algorithms of Gamage and Lasenby, bias compensation, symmetrical CoR estimation, normalisation method and helical axis. Ten subjects per... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5103751 Sun, 31 Jul 2011 23:00:00 +0100 5103751 http://www.medworm.com/index.php?rid=5103750&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21806414%26dopt%3DAbstract This study concluded that any method of time integration could be used for these meshes and time steps size. PMID: 21806414 [PubMed - as supplied by publisher] (Source: Computer Methods in Biomechanics and Biomedical Engineering) Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5103750 Sun, 31 Jul 2011 23:00:00 +0100 5103750 http://www.medworm.com/index.php?rid=5103749&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21806415%26dopt%3DAbstract Authors: Yucesoy CA, Seref-Ferlengez Z, Huijing PA The goal was to assess the effects of multiple aponeurotomy on mechanics of muscle with extramuscular myofascial connections. Using finite element modelling, effects of combinations of the intervention carried out at a proximal (P), an intermediate (I) and a distal (D) location were studied: (1) Case P, (2) Case P-I, (3) Case P-D and (4) Case P-I-D. Compared to Case P, the effects of multiple interventions on muscle geometry and sarcomere lengths were sizable for the distal population of muscle fibres: e.g. at high muscle length (1) summed gap lengths between the cut ends of aponeurosis increased by 16, 25 and 27% for Cases P-I, P-D and P-I-D, respectively, (2) characteristic substantial sarcomere shortening became more pronounced (mea... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5103749 Sun, 31 Jul 2011 23:00:00 +0100 5103749 http://www.medworm.com/index.php?rid=5103748&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21806416%26dopt%3DAbstract Authors: De Lazzari C Mathematical modelling of the cardiovascular system (CVS) can help in understanding the complex interactions between both the ventricles and the septum. By describing the behaviour of the left (right) ventricular free wall, atria and septum using the variable elastance models, it is possible to reproduce their interactions. By relating the mechanical properties of both atria and both ventricles to the electrocardiogram (ECG) signal, it is possible to analyse the effects produced by different ECG delay on haemodynamic parameters. In the cardiovascular field, the incorrect interactions between septum and both ventricular free walls are based on many pathological conditions, i.e. symptomatic heart failure resulting from systolic dysfunction, ischemic dilated cardiomy... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5103748 Sun, 31 Jul 2011 23:00:00 +0100 5103748 http://www.medworm.com/index.php?rid=5103758&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21793683%26dopt%3DAbstract Authors: Yeadon MR, Knight JP Training the gymnasts to view the landing area when learning aerial skills may lead to more consistent landings but can be problematic and potentially dangerous. A virtual environment allowing gymnasts to get introduced to viewing techniques safely is presented. The system is based on existing simulation models and visualisation software, and is implemented using client-server technology to allow reuse with new simulation models in the future. PMID: 21793683 [PubMed - as supplied by publisher] (Source: Computer Methods in Biomechanics and Biomedical Engineering) Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5103758 Tue, 26 Jul 2011 23:00:00 +0100 5103758 http://www.medworm.com/index.php?rid=5057646&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21756121%26dopt%3DAbstract Authors: Pataky TC Statistical parametric mapping (SPM) is a topological methodology for detecting field changes in smooth n-dimensional continua. Many classes of biomechanical data are smooth and contained within discrete bounds and as such are well suited to SPM analyses. The current paper accompanies release of 'SPM1D', a free and open-source Python package for conducting SPM analyses on a set of registered 1D curves. Three example applications are presented: (i) kinematics, (ii) ground reaction forces and (iii) contact pressure distribution in probabilistic finite element modelling. In addition to offering a high-level interface to a variety of common statistical tests like t tests, regression and ANOVA, SPM1D also emphasises fundamental concepts of SPM theory through stand-alone e... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5057646 Wed, 13 Jul 2011 23:00:00 +0100 5057646 http://www.medworm.com/index.php?rid=5057649&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21749272%26dopt%3DAbstract Authors: Studer H, Riedwyl H, Büchler P A mechanical balance between intraocular pressure and tissue stiffness defines the refractive shape of the human cornea. More and more daily surgical procedures modify that shape to achieve vision correction, which increases the demand for a profound understanding of the tissue mechanics. The wide variety of published mechanical properties foreshadows the difficulty of this task. The aim of this study is to show that such problems may arise from using the inverse method for fitting material models with multiple coefficients to a limited number (usually one) of experimental data. Using multiple sets of experimental data for the fitting process is proposed as a possible solution. PMID: 21749272 [PubMed - as supplied by publisher] (Source: Comp... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5057649 Tue, 12 Jul 2011 23:00:00 +0100 5057649 http://www.medworm.com/index.php?rid=5057648&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21749275%26dopt%3DAbstract Authors: Riches PE Permeability controls the fluid flow into and out of soft tissue, and plays an important role in maintaining the health status of such tissue. Accurate determination of the parameters that define permeability is important for the interpretation of models that incorporate such processes. This paper describes the determination of strain-dependent permeability parameters from the nonlinear biphasic equation from experimental data of different sampling frequencies using the Nelder-Mead simplex method. The ability of this method to determine the global optimum was assessed by constructing the whole manifold arising from possible parameter combinations. Many parameter combinations yielded similar fits with the Nelder-Mead algorithm able to identify the global maximum withi... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5057648 Tue, 12 Jul 2011 23:00:00 +0100 5057648 http://www.medworm.com/index.php?rid=5057647&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21749276%26dopt%3DAbstract Authors: El Masri F, Sapin de Brosses E, Rhissassi K, Skalli W, Mitton D Up to now, due to cortical thickness and imaging resolution, it is not possible to derive subject-specific mechanical properties on the 'vertebral shell' from imaging modalities applicable in vivo. As a first step, the goal of this study was to assess the apparent Young's modulus of vertebral cortico-cancellous bone specimens using an inverse method. A total of 22 cortico-cancellous specimens were harvested from 22 vertebral bodies. All specimens were tested in compression until failure. To compute the apparent Young's modulus of the specimen from the inverse method, the boundary conditions of the biomechanical experiments were faithfully reproduced in a finite element model (FEM), and an optimisation routine was ... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5057647 Tue, 12 Jul 2011 23:00:00 +0100 5057647 http://www.medworm.com/index.php?rid=5057651&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21749225%26dopt%3DAbstract This study aims to develop a representative stratified model of human skin, informed by in vivo data. A multilayer finite element model incorporating the epidermis, dermis and hypodermis was established. This was correlated with a series of in-vivo indentation measurements, and the Ogden material coefficients were optimised using a material parameter extraction algorithm. The finite element simulation was subsequently used to model microneedle application to human skin before penetration and was validated by comparing these predictions with the in-vivo measurements. Our model has provided an excellent tool to predict micron-scale human skin deformation in vivo and is currently being used to inform optimised microneedle designs. PMID: 21749225 [PubMed - as supplied by publisher] (Source... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5057651 Mon, 11 Jul 2011 23:00:00 +0100 5057651 http://www.medworm.com/index.php?rid=5057650&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21749226%26dopt%3DAbstract Authors: Badel P, Avril S, Lessner S, Sutton M The role of mechanics is known to be of primary order in many arterial diseases; however, determining mechanical properties of arteries remains a challenge. This paper discusses the identifiability of the passive mechanical properties of a mouse carotid artery, taking into account the orientation of collagen fibres in the medial and adventitial layers. On the basis of 3D digital image correlation measurements of the surface strain during an inflation/extension test, an inverse identification method is set up. It involves a 3D finite element mechanical model of the mechanical test and an optimisation algorithm. A two-layer constitutive model derived from the Holzapfel model is used, with five and then seven parameters. The five-parameter mo... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5057650 Mon, 11 Jul 2011 23:00:00 +0100 5057650 http://www.medworm.com/index.php?rid=5057654&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21736428%26dopt%3DAbstract Authors: Piechota J, Prywer J, Torzewska A In the present work, we carried out density functional calculations of struvite - the main component of the so-called infectious urinary stones - to study its structural and elastic properties. Using a local density approximation and a generalised gradient approximation, we calculated the equilibrium structural parameters and elastic constants C ( ijkl ). At present, there is no experimental data for these elastic constants C ( ijkl ) for comparison. Besides the elastic constants, we also present the calculated macroscopic mechanical parameters, namely the bulk modulus (K), the shear modulus (G) and Young's modulus (E). The values of these moduli are found to be in good agreement with available experimental data. Our results imply that the mec... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5057654 Wed, 06 Jul 2011 23:00:00 +0100 5057654 http://www.medworm.com/index.php?rid=5057653&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21736429%26dopt%3DAbstract Authors: Anderst WJ An automated technique to measure neural foramen cross-sectional area during in vivo, multi-planar movements is presented. This method combines three-dimensional (3D) models of each vertebra obtained from CT scans with in vivo movement data collected using high-speed biplane radiography. A novel computer algorithm that automatically traces a path around the bony boundary that defines the neural foramen at every frame of X-ray data is described. After identifying the neural foramen boundary, the cross-sectional area is calculated. The technique is demonstrated using data collected from a patient with cervical radiculopathy who is tested before and after conservative treatment. The technique presented here can be applied when 3D, dynamic, functional movements are perf... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5057653 Wed, 06 Jul 2011 23:00:00 +0100 5057653 http://www.medworm.com/index.php?rid=5057652&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21736445%26dopt%3DAbstract Authors: Torii R, Oshima M Patient-specific haemodynamic computations have been used as an effective tool in researches on cardiovascular disease associated with haemodynamics such as atherosclerosis and aneurysm. Recent development of computer resource has enabled 3D haemodynamic computations in wide-spread arterial network but there are still difficulties in modelling vascular geometry because of noise and limited resolution in medical images. In this paper, an integrated framework to model an arterial network tree for patient-specific computational haemodynamic study is developed. With this framework, 3D vascular geometry reconstruction of an arterial network and quantification of its geometric feature are aimed. The combination of 3D haemodynamic computation and vascular morphology... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5057652 Wed, 06 Jul 2011 23:00:00 +0100 5057652 http://www.medworm.com/index.php?rid=5008999&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21728739%26dopt%3DAbstract Authors: Lopomo N, Zaffagnini S, Signorelli C, Bignozzi S, Giordano G, Marcheggiani Muccioli GM, Visani A Even if pivot-shift (PS) test has been clinically used to specifically detect anterior cruciate ligament (ACL) injury, the main problem in using this combined test has been yet associated with the difficulty of clearly quantifying its outcome. The goal of this study was to describe an original non-invasive methodology used to quantify PS test, highlighting its possible clinical reliability. The method was validated on 66 consecutive unilateral ACL-injured patients. A commercial triaxial accelerometer was non-invasively mounted on patient's tibia, the corresponding 3D acceleration was acquired during PS test execution and a set of specific parameters were automatically identified on... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5008999 Mon, 04 Jul 2011 23:00:00 +0100 5008999 http://www.medworm.com/index.php?rid=5009001&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21722048%26dopt%3DAbstract Authors: Bender A, Bergmann G Forces measured in human joints vary considerably when an activity such as walking is carried out by different subjects or when it is repeated. 'Typical' standardised force-time patterns are needed to test and improve joint implants. Mechanically most important for their endurance are the magnitudes and times of force maxima and minima. They should equal the arithmetic means from the single measurements. Similar problems exist when evaluating other strongly varying signals, as in gait analysis. The new method to calculate typical signals (TSs) enhances existing dynamic time warping (DTW) procedures. It allows us to combine any number of signals. The sequence of input signals - used for calculating the TS - has only a minor influence. The accuracy of the me... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5009001 Sun, 03 Jul 2011 23:00:00 +0100 5009001 http://www.medworm.com/index.php?rid=5009000&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21722065%26dopt%3DAbstract Authors: Abouhossein A, Weisse B, Ferguson SJ PMID: 21722065 [PubMed - as supplied by publisher] (Source: Computer Methods in Biomechanics and Biomedical Engineering) Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5009000 Sun, 03 Jul 2011 23:00:00 +0100 5009000 http://www.medworm.com/index.php?rid=5009002&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21711216%26dopt%3DAbstract Authors: Spyrou LA, Aravas N This paper describes a finite element scheme for realistic muscle-driven simulation of human foot movements. The scheme is used to simulate human ankle plantar flexion. A three-dimensional anatomically detailed finite element model of human foot and lower leg is developed and the idea of generating natural foot movement based entirely on the contraction of the plantar flexor muscles is used. The bones, ligaments, articular cartilage, muscles, tendons, as well as the rest soft tissues of human foot and lower leg are included in the model. A realistic three-dimensional continuum constitutive model that describes the biomechanical behaviour of muscles and tendons is used. Both the active and passive properties of muscle tissue are accounted for. The materials ... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5009002 Tue, 28 Jun 2011 23:00:00 +0100 5009002 http://www.medworm.com/index.php?rid=5009003&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21711164%26dopt%3DAbstract Authors: Butz KD, Merrell G, Nauman EA The problem of modelling stresses incurred at the finger joints is critical to the design of durable joint replacements in the hand. The goal of this study was to characterise the forces and stresses at the finger and thumb joints occurring during activities such as typing at a keyboard, playing piano, gripping a pen, carrying a weight and opening a jar. The metacarpal and proximal phalanx were modelled using a COMSOL-based finite element analysis. Analysis of these activities indicates that joint forces in excess of 100 N may be common at the metacarpophalangeal joint (MCP) due to carrying objects such as groceries or while opening jars. The model predicted that stresses in excess of 2 MPa, similar to stresses at the hip, occur at the MCP with ... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5009003 Mon, 27 Jun 2011 23:00:00 +0100 5009003 http://www.medworm.com/index.php?rid=5009004&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21707247%26dopt%3DAbstract Comment on "A multibody modelling approach to determine load sharing between passive elements of the lumbar spine" by Abouhossein et al. Comput Methods Biomech Biomed Engin. 2011 Jun 27; Authors: Aspden RM PMID: 21707247 [PubMed - as supplied by publisher] (Source: Computer Methods in Biomechanics and Biomedical Engineering) Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=5009004 Sun, 26 Jun 2011 23:00:00 +0100 5009004 http://www.medworm.com/index.php?rid=4961454&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21660779%26dopt%3DAbstract Authors: Bazrgari B, Nussbaum MA, Madigan ML The use of system identification to quantify trunk mechanical properties is growing in biomechanics research. The effects of several experimental and modelling factors involved in the system identification of trunk mechanical properties were investigated. Trunk kinematics and kinetics were measured in six individuals when exposed to sudden trunk perturbations. Effects of motion sensor positioning and properties of elements between the perturbing device and the trunk were investigated by adopting different models for system identification. Results showed that by measuring trunk kinematics at a location other than the trunk surface, the deformation of soft tissues is erroneously included into trunk kinematics and results in the trunk being pre... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=4961454 Tue, 31 May 2011 23:00:00 +0100 4961454 http://www.medworm.com/index.php?rid=4961453&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21660780%26dopt%3DAbstract In this study, experimental photoelastic method and finite element techniques were compared using an idealised AAA geometry. There was good agreement between the numerical and experimental results. At the proximal and distal end of the AAA model, the maximum differences in principle strain for an internal pressure of 120 mmHg had differences ranging from 0.03 to 10.01%. The maximum difference in principle strain for the photoelastic and the finite element model at a pressure of 120 mmHg was 0.167 and 0.158, respectively. The current research strengthens the case for using FEA as an adjunct to the current clinical practice of utilising diameter measurement for intervention timing. PMID: 21660780 [PubMed - as supplied by publisher] (Source: Computer Methods in Biomechanics and Biomedic... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=4961453 Tue, 31 May 2011 23:00:00 +0100 4961453 http://www.medworm.com/index.php?rid=4961452&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21660781%26dopt%3DAbstract Authors: Sokolis DP There is a scarcity of data regarding the mechanical properties of the ureter, although this would facilitate our understanding of its physiology and pathophysiology, and the development of suitable biomaterials for replacement. There is hence an urgent need for multiaxial experimental data and methodical constitutive formulations, which we aim at presenting through this report. The zero-stress state of wall tissue, serving as the starting geometry for biomechanical analyses, was accordingly determined and the 3D passive behaviour of ureteral specimens, isolated from healthy rabbits, was studied under a physiologic range of finite inflation and longitudinal extension. Two most-commonly employed descriptors of soft tissue behaviour were chosen to fit the material res... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=4961452 Tue, 31 May 2011 23:00:00 +0100 4961452 http://www.medworm.com/index.php?rid=4961451&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21660782%26dopt%3DAbstract Authors: Oliveira FP, Sousa A, Santos R, Tavares JM This paper presents a new computational framework for automatic foot classification from digital plantar pressure images. It classifies the foot as left or right and simultaneously calculates two well-known footprint indices: the Cavanagh's arch index (AI) and the modified AI. The accuracy of the framework was evaluated using a set of plantar pressure images from two common pedobarographic devices. The results were outstanding, as all feet under analysis were correctly classified as left or right and no significant differences were observed between the footprint indices calculated using the computational solution and the traditional manual method. The robustness of the proposed framework to arbitrary foot orientations and to the acqui... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=4961451 Tue, 31 May 2011 23:00:00 +0100 4961451 http://www.medworm.com/index.php?rid=4912666&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21630165%26dopt%3DAbstract Authors: Martinez F, Gomez F, Romero E The gait pattern of a particular patient can be altered in a large set of pathologies. Tracking the body centre-of-mass (CoM) during the gait allows a quantitative evaluation of these diseases at comparing the gait with normal patterns. A correct estimation of this variable is still an open question because of its non-linearity and inaccurate location. This paper presents a novel strategy for tracking the CoM, using a biomechanical gait model whose parameters are determined by a Bayesian strategy. A particle filter is herein implemented for predicting the model parameters from a set of markers located at the sacral zone. The present approach is compared with other conventional tracking methods and decreases the calculated root mean squared error i... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=4912666 Tue, 31 May 2011 23:00:00 +0100 4912666 http://www.medworm.com/index.php?rid=4912665&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21644115%26dopt%3DAbstract Authors: Kuznetsov AV This paper develops a model of nanoparticle transport in neurons. It is assumed that nanoparticles are transported inside endocytic vesicles by a combined effect of dynein-driven transport and diffusion. It is further assumed that in axons nanoparticles are internalised only at axon terminals, whereas in dendrites nanoparticles can enter through the entire plasma membrane. This causes differences in transport of nanoparticles in axons and dendrites; these differences are investigated in this paper. Another difference is microtubule (MT) orientation in axons and dendrites; in axons, all MTs have their plus-ends oriented towards the axon terminal; in a proximal region of a dendrite, MTs have mixed orientation, whereas in a distal dendritic region the MT orientation ... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=4912665 Tue, 31 May 2011 23:00:00 +0100 4912665 http://www.medworm.com/index.php?rid=4912669&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21614705%26dopt%3DAbstract This study established a 3D foot FE model using software ANSYS 11.0. After validating the FE model, this study created low-arched, high-arched and normal-arched foot FE models. The FE analysis found that both the stress and strain on the plantar fascia and metatarsal were higher in the high-arched foot, whereas the stress and strain on the calcaneous, navicular and cuboid were higher in low-arched foot. Additionally, forefoot pressure was increased with an increase in arch height. PMID: 21614705 [PubMed - as supplied by publisher] (Source: Computer Methods in Biomechanics and Biomedical Engineering) Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=4912669 Sat, 30 Apr 2011 23:00:00 +0100 4912669 http://www.medworm.com/index.php?rid=4912668&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21614706%26dopt%3DAbstract Authors: Comiskey DP, Macdonald BJ, McCartney WT, Synnott K, O'Byrne J The formation of a fracture callus in vivo tends to form in a structurally efficient manner distributing tissues where mechanical stimulus persists. Therefore, it is proposed that the formation of a fracture callus can be modelled in silico by way of an optimisation algorithm. This was tested by generating a finite element model of a transversal bone fracture embedded in a large tissue domain which was subjected to axial, bending and torsional loads. It was found that the relative fragment motion induced a compressive strain field in the early callus tissue which could be utilised to simulate the formation of external callus structures through an iterative optimisation process of tissue maintenance and removal. The ... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=4912668 Sat, 30 Apr 2011 23:00:00 +0100 4912668 http://www.medworm.com/index.php?rid=4912667&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21614707%26dopt%3DAbstract Authors: Dorn TW, Lin YC, Pandy MG Computational analyses of leg-muscle function in human locomotion commonly assume that contact between the foot and the ground occurs at discrete points on the sole of the foot. Kinematic constraints acting at these contact points restrict the motion of the foot and, therefore, alter model calculations of muscle function. The aim of this study was to evaluate how predictions of muscle function obtained from musculoskeletal models are influenced by the model used to simulate ground contact. Both single- and multiple-point contact models were evaluated. Muscle function during walking and running was determined by quantifying the contributions of individual muscles to the vertical, fore-aft and mediolateral components of the ground reaction force (GRF). ... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=4912667 Sat, 30 Apr 2011 23:00:00 +0100 4912667 http://www.medworm.com/index.php?rid=4865805&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21574077%26dopt%3DAbstract Conclusions: These two computational techniques have, and will continue to, provide significant contributions towards the development of interventions. It is hoped that this article will help focus ongoing technological developments by highlighting areas of success, but also areas of under development. PMID: 21574077 [PubMed - as supplied by publisher] (Source: Computer Methods in Biomechanics and Biomedical Engineering) Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=4865805 Sat, 30 Apr 2011 23:00:00 +0100 4865805 http://www.medworm.com/index.php?rid=4865804&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21574078%26dopt%3DAbstract In this study, we used an empirically verified model of creep strain accumulation, in a simulation of 10 non-homogeneous samples, which were created from micro-CT scans of human cortical bone of the femur midshaft obtained from a 74-year-old female cadaver. These non-homogeneous samples incorporate the presence of Haversian canals and resorption cavities. The influence of inhomogeneity on the response and variation in the samples in both creep and stress relaxation tests are examined. The relationship between steady-state creep rate, applied loads (stress relaxation and creep tests) and microstructure, that is bone apparent porosity, is obtained. These relations may provide insight into damage accumulation of whole human bones and be relevant to studies on osteoporosis. PMID: 21574078 ... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=4865804 Sat, 30 Apr 2011 23:00:00 +0100 4865804 http://www.medworm.com/index.php?rid=4865803&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21574079%26dopt%3DAbstract Authors: Conte C, Masson C, Arnoux PJ To prevent traumas to abdominal organs, the selection of efficient safety devices should be based on a detailed knowledge of injury mechanisms and related injury criteria. In this sense, finite element (FE) simulation coupled with experiment could be a valuable tool to provide a better understanding of the behaviour of internal organs under crash conditions. This work proposes a methodology based on inverse analysis which combines exploration process optimisation and robustness study to obtain mechanical behaviour of the complex structure of the liver through FE simulation. The liver characterisation was based on Mooney-Rivlin hyperelastic behaviour law considering whole liver structure under uniform quasi-static compression. With the global method... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=4865803 Sat, 30 Apr 2011 23:00:00 +0100 4865803 http://www.medworm.com/index.php?rid=4865802&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21590555%26dopt%3DAbstract Authors: Homyk A, Orsi A, Wibby S, Yang N, Nayeb-Hashemi H, Canavan PK Anterior cruciate ligament (ACL) disruption is a common injury that is detrimental to an athlete's quality of life. Determining the mechanisms that cause ACL injury is important in order to develop proper interventions. A failure locus defined as various combinations of loadings and movements, internal/external rotation of femur and valgus and varus moments at a 25(o) knee flexion angle leading to ACL failure was obtained. The results indicated that varus and valgus movements were more dominant to the ACL injury than femoral rotation. Also, Von Mises stress in the lateral tibial cartilage during the valgus ACL injury mechanism was 83% greater than that of the medial cartilage during the varus mechanism of ACL injury... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=4865802 Sat, 30 Apr 2011 23:00:00 +0100 4865802 http://www.medworm.com/index.php?rid=4865801&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21598127%26dopt%3DAbstract Authors: Urooj S, Khan M, Ansari AQ, Lay-Ekuakille A, Salhan AK Pulmonary oedema is a life-threatening disease that requires special attention in the area of research and clinical diagnosis. Computer-based techniques are rarely used to quantify the intrathoracic fluid volume (IFV) for diagnostic purposes. This paper discusses a software program developed to detect and diagnose pulmonary oedema using LabVIEW. The software runs on anthropometric dimensions and physiological parameters, mainly transthoracic electrical impedance (TEI). This technique is accurate and faster than existing manual techniques. The LabVIEW software was used to compute the parameters required to quantify IFV. An equation relating per cent control and IFV was obtained. The results of predicted TEI and measured TEI... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=4865801 Sat, 30 Apr 2011 23:00:00 +0100 4865801 http://www.medworm.com/index.php?rid=4865800&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21598128%26dopt%3DAbstract This article reports on the geometric optimisation of a T-shaped biochip microchannel fluidic separator aiming to maximise the separation efficiency of plasma from blood through the improvement of the unbalanced separation performance among different channel bifurcations. For this purpose, an algebraic analysis is firstly implemented to identify the key parameters affecting fluid separation. A numerical optimisation is then carried out to search the key parameters for improved separation performance of the biochip. Three parameters, the interval length between bifurcations, the main channel length from the outlet to the bifurcation region and the side channel geometry, are identified as the key characteristic sizes and defined as optimisation variables. A balanced flow rate ratio between t... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=4865800 Sat, 30 Apr 2011 23:00:00 +0100 4865800 http://www.medworm.com/index.php?rid=4865799&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21598129%26dopt%3DAbstract The objective of this study is to develop, calibrate and validate a TKR kinematics simulation considering multiple TKR geometries, an accurate friction model and simulation parameters determined using a systematic optimisation method. The calibrated model was able to predict TKR kinematics for different TKR geometries, and is ideal for screening new implant designs, reducing the number of experiments required at the design stage. PMID: 21598129 [PubMed - as supplied by publisher] (Source: Computer Methods in Biomechanics and Biomedical Engineering) Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=4865799 Sat, 30 Apr 2011 23:00:00 +0100 4865799 http://www.medworm.com/index.php?rid=4865798&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21598130%26dopt%3DAbstract Authors: Moustakidis SP, Theocharis JB, Giakas G An efficient wavelet-based feature selection (FS) method is proposed in this paper for subject recognition using ground reaction force measurements. Our approach relies on a local fuzzy evaluation measure with respect to patterns that reveal the adequacy of data coverage for each feature. Furthermore, FS is driven by a fuzzy complementary criterion (FuzCoC) which assures that those features are iteratively introduced, providing the maximum additional contribution with regard to the information content given by the previously selected features. On the basis of the principles of FuzCoC, we develop two novel techniques. At Stage 1, wavelet packet (WP) decomposition of gaits is accomplished to obtain a set of discriminating frequency sub-ban... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=4865798 Sat, 30 Apr 2011 23:00:00 +0100 4865798 http://www.medworm.com/index.php?rid=4865797&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21598131%26dopt%3DAbstract Authors: Qu X, Nussbaum MA A 3D balance control model of quiet upright stance is presented, based on an optimal control strategy, and evaluated in terms of its ability to simulate postural sway in both the anterior-posterior and medial-lateral directions. The human body was represented as a two-segment inverted pendulum. Several assumptions were made to linearise body dynamics, for example, that there was no transverse rotation during upright stance. The neural controller was presumed to be an optimal controller that generates ankle control torque and hip control torque according to certain performance criteria. An optimisation procedure was used to determine the values of unspecified model parameters including random disturbance gains and sensory delay times. This model was used to si... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=4865797 Sat, 30 Apr 2011 23:00:00 +0100 4865797 http://www.medworm.com/index.php?rid=4865796&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21604219%26dopt%3DAbstract Authors: Lee HP, Zhuang H A parametric study to investigate the compressive and the shear stress distributions for various edge shapes created during penetrating keratoplasty (PK) using femtosecond laser is reported. The finite element analysis has been implemented using ABAQUS to study the cornea with various edge shapes, namely the standard edge shape, the zigzag edge shape, the top hat edge shape and the mushroom edge shape for PK. The ratio of maximum compressive stress to maximum shear stress is used as the main factor to assess the relative merits of wound healing rate for different edge shapes. For the typical values of tissue mechanical properties, the zigzag edge shape has the highest ratio of maximum compressive stress to maximum shear stress (11.1 in the xy-direction and 3.7... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=4865796 Sat, 30 Apr 2011 23:00:00 +0100 4865796 http://www.medworm.com/index.php?rid=4865795&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21604220%26dopt%3DAbstract Authors: Linge SO Much attention has been devoted to how playground swing amplitudes are built up by swinger techniques, i.e. body actions. However, very little attention has been given to the requirements that such swinger techniques place on the swinger himself. The purpose of this study was to find out whether different swinger techniques yield significantly different maximum torques, endurance and coordinative skills, and also to identify preferable techniques. We modelled the seated swinger as a rigid dumbbell and compared three different techniques. A series of computer simulations were run with each technique, testing the performance with different body rotational speeds, delayed onset of body rotation and different body mass distributions, as swing amplitudes were brought up to... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=4865795 Sat, 30 Apr 2011 23:00:00 +0100 4865795 http://www.medworm.com/index.php?rid=4865794&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21604221%26dopt%3DAbstract Authors: Wang Y, Qin QH Pulsed electromagnetic field (PEMF) devices have been used clinically to slow down osteoporosis and accelerate the healing of bone fractures for many years. However, the underlying mechanism by which bone remodelling under PEMF is regulated remains poorly understood. In this paper, a mathematical model of bone cell population of bone remodelling under PEMF at cellular level is developed to address this issue for the first time. On the basis of this model and control theory, parametric study of control mechanisms is carried out and a number of possible control mechanisms are identified. These findings will help further the understanding of bone remodelling under PEMF and advance therapies and pharmacological developments in clinical trials. PMID: 21604221 [Pu... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=4865794 Sat, 30 Apr 2011 23:00:00 +0100 4865794 http://www.medworm.com/index.php?rid=4865793&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21604222%26dopt%3DAbstract Authors: Cunningham LM, Nugent CD, Moore G, Finlay DD, Craig D The prevalence of Parkinson's disease (PD) is increasing due to an ageing population. It is an unpredictable disease which requires regular assessment and monitoring. Current techniques used to assess PD are subjective. Clinicians observe movements made by a patient and subsequently rate the level of severity of, for example tremor or slowness of movement. Within this work, we have developed and evaluated a prototype computer-based assessment tool capable of collecting information on the movement difficulties present in PD. Twenty participants took part in an assessment of the tool, 10 of whom were diagnosed with PD and 10 were without the disease. Following the usage of the tool, it was found that there was a significant d... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=4865793 Sat, 30 Apr 2011 23:00:00 +0100 4865793 http://www.medworm.com/index.php?rid=4865792&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21604223%26dopt%3DAbstract Authors: Mehrez L, Browne M Hip replacement constructs are paradigms of uncertain systems, and as such are suited to the application of probabilistic methods to assess their structural integrity. In order to gain confidence in a probabilistic model, it would be useful to verify the findings with experimental data; however, this is difficult to achieve in practice because of the exhaustive number of parameter combinations that need to be tested. As an alternative to experimental testing, benchmarking can be carried out provided a known analytical solution is available. To this end, a simplified 2D two-beam model of the femoral part of a total hip replacement construct was utilised to analyse uncertainties and variability in the construct as it is subjected to load. The use of a simplifi... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=4865792 Sat, 30 Apr 2011 23:00:00 +0100 4865792 http://www.medworm.com/index.php?rid=4865791&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21607885%26dopt%3DAbstract Authors: Wolf A, Senesh M Modelling of soft tissue motion is required in many areas, such as computer animation, surgical simulation, 3D motion analysis and gait analysis. In this paper, we will focus on the use of modelling of skin deformation during 3D motion analysis. The most frequently used method in 3D human motion analysis involves placing markers on the skin of the analysed segment which is composed of the rigid bone and the surrounding soft tissues. Skin and soft tissue deformations introduce a significant artefact which strongly influences the resulting bone position, orientation and joint kinematics. For this study, we used a statistical solid dynamics approach which is a combination of several previously reported tools: the point cluster technique (PCT) and a Kalman filter ... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=4865791 Sat, 30 Apr 2011 23:00:00 +0100 4865791 http://www.medworm.com/index.php?rid=4865790&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21607886%26dopt%3DAbstract Authors: Tang G, Qian LW, Wei GF, Wang HS, Wang CT Muscle force estimation (MFE) has become more and more important in exploring principles of pathological movement, studying functions of artificial muscles, making surgery plan for artificial joint replacement, improving the biomechanical effects of treatments and so on. At present, existing software are complex for professionals, so we have developed a new software named as concise MFE (CMFE). CMFE which provides us a platform to analyse muscle force in various actions includes two MFE methods (static optimisation method and electromyographic-based method). Common features between these two methods have been found and used to improve CMFE. A case studying the major muscles of lower limb of a healthy subject walking at normal speed has... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=4865790 Sat, 30 Apr 2011 23:00:00 +0100 4865790 http://www.medworm.com/index.php?rid=4865789&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21607887%26dopt%3DAbstract Authors: Lo CC, Tsai KJ, Chen SH, Zhong ZC, Hung C The Coflex device may provide stability to the surgical segment in extension but does not restore stability in other motion. Recently, a modified version called the Coflex rivet has been developed. The effects of Coflex and Coflex rivet implantation on the adjacent segments are still not clear; therefore, the purpose of this study was to investigate the biomechanical differences between Coflex and Coflex rivet implantation by using finite element analyses. The results show that the Coflex implantation can provide stability in extension, lateral bending, and axial rotation at the surgical segment, and it had no influence at adjacent segments except for extension. The Coflex rivet implantation can provide stability in all motions and red... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=4865789 Sat, 30 Apr 2011 23:00:00 +0100 4865789 http://www.medworm.com/index.php?rid=4865788&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21607888%26dopt%3DAbstract Authors: Carlsson P, Tinnsten M, Ainegren M A program for numerical simulation of a whole ski race, from start to finish, is developed in MATLAB. The track is modelled by a set of cubical splines in two dimensions and can be used to simulate a track in a closed loop or with the start and finish at different locations. The forces considered in the simulations are gravitational force, normal force between snow and skis, drag force from the wind, frictional force between snow and ski and driving force from the skier. The differential equations of motion are solved from start to finish with the Runge-Kutta method. Different wind situations during the race can be modelled, as well as different glide conditions on different parts of the track. It is also possible to vary the available power ... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=4865788 Sat, 30 Apr 2011 23:00:00 +0100 4865788 http://www.medworm.com/index.php?rid=4865787&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21607889%26dopt%3DAbstract In this study, we have analysed heel strike (HS) and toe off (TO) of normal individuals and hemiplegic patients, taking advantage of output curves acquired from various sensors, and verified the validity of sensor detection methods and their effectiveness when they were used for hemiplegic gaits. Gait phase detections using three different motion sensors were valid, since they all had reliabilities more than 95%, when compared with foot velocity algorithm. Results showed that the tilt sensor and the gyrosensor could detect gait phase more accurately in normal individuals. Vertical acceleration could detect HS most accurately in hemiplegic patient group A. The gyrosensor could detect HS and TO most accurately in hemiplegic patient groups A and B. The detection of TO from all sensor signals ... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=4865787 Sat, 30 Apr 2011 23:00:00 +0100 4865787 http://www.medworm.com/index.php?rid=4759107&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21516525%26dopt%3DAbstract Authors: Oomens C, Baaijens F PMID: 21516525 [PubMed - in process] (Source: Computer Methods in Biomechanics and Biomedical Engineering) Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=4759107 Thu, 28 Apr 2011 10:30:32 +0100 4759107 http://www.medworm.com/index.php?rid=4759106&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21516526%26dopt%3DAbstract This study describes the development of a continuum model that represents a cell-in-gel culture system used in bone-tissue engineering, namely that of a cell aggregate embedded in a hydrogel. Cell adhesion is modelled through the use of non-local (integral) terms in the partial differential equations. The simulation results demonstrate that the effects of cell-cell and cell-matrix adhesion are particularly important for the survival and growth of the cell population and the production of extracellular matrix by the cells, concurring with experimental observations in the literature. PMID: 21516526 [PubMed - in process] (Source: Computer Methods in Biomechanics and Biomedical Engineering) Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=4759106 Thu, 28 Apr 2011 10:30:28 +0100 4759106 http://www.medworm.com/index.php?rid=4759105&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21516527%26dopt%3DAbstract In conclusion, non-constant diffusion renders significant effects on both the microscopic ECM development and the macroscopic mechanical properties of developing tissue-engineered cartilage. PMID: 21516527 [PubMed - in process] (Source: Computer Methods in Biomechanics and Biomedical Engineering) Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=4759105 Thu, 28 Apr 2011 10:30:25 +0100 4759105 http://www.medworm.com/index.php?rid=4759104&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21516528%26dopt%3DAbstract Authors: Vernerey FJ, Farsad M Most animal cells are surrounded by a thin layer of actin meshwork below their membrane, commonly known as the actin cortex (or cortical membrane). An increasing number of studies have highlighted the role of this structure in many cell functions including contraction and locomotion, but modelling has been limited by the fact that the membrane thickness (about 1 μm) is usually much smaller than the typical size of a cell (10-100 μm). To overcome theoretical and numerical issues resulting from this observation, we introduce in this paper a continuum formulation, based on surface elasticity, that views the cortex as an infinitely thin membrane that can resists tangential deformation. To accurately model the large deformations of cells, we introduced equ... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=4759104 Thu, 28 Apr 2011 10:30:21 +0100 4759104 http://www.medworm.com/index.php?rid=4759103&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21516529%26dopt%3DAbstract Authors: Zeng X, Li S Recently, we have developed a multiscale soft matter cell model aiming at improving the understanding of mechanotransduction mechanism of stem cells, which is responsible for information exchange between cells and their extracellular environment. In this paper, we report the preliminary results of our research on multiscale modelling and simulation of soft contact and adhesion of stem cells. The proposed multiscale soft matter cell model may be used to model soft contact and adhesion between cells and their extracellular substrates. To the authors' best knowledge, this may be the first time that a soft matter model has been developed for cell contact and adhesion. Moreover, we have developed and implemented a Lagrange-type meshfree Galerkin formulation and related... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=4759103 Thu, 28 Apr 2011 10:30:17 +0100 4759103 http://www.medworm.com/index.php?rid=4759102&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21516530%26dopt%3DAbstract Authors: Han SJ, Sniadecki NJ Cell migration relies on traction forces in order to propel a cell. Several computational models have been developed that help explain the trajectory that cells take during migration, but little attention has been placed on traction forces during this process. Here, we investigated the spatiotemporal dynamics of cell migration by using a bio-chemical-mechanical contractility model that incorporates the first steps of cell migration on an array of posts. In the model, formation of a new adhesion causes a reactivation of stress fibre assembly within a cell. The model was able to predict the spatial distribution of traction forces observed with previous experiments. Moreover, the model found that the strain energy exerted by the traction forces of a migrating... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=4759102 Thu, 28 Apr 2011 10:30:14 +0100 4759102 http://www.medworm.com/index.php?rid=4759101&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21516531%26dopt%3DAbstract Authors: Kabaso D, Gongadze E, Perutkova S, Matschegewski C, Kralj-Iglic V, Beck U, van Rienen U, Iglic A Due to oxidation and adsorption of chloride and hydroxyl anions, the surface of titanium (Ti) implants is negatively charged. A possible mechanism of the attractive interaction between the negatively charged Ti surface and the negatively charged osteoblasts is described theoretically. It is shown that adhesion of positively charged proteins with internal charge distribution may give rise to attractive interaction between the Ti surface and the osteoblast membrane. A dynamic model of the osteoblast attachment is presented in order to study the impact of geometrically structured Ti surfaces on the osteoblasts attachment. It is indicated that membrane-bound protein complexes (PCs) may... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=4759101 Thu, 28 Apr 2011 10:30:10 +0100 4759101 http://www.medworm.com/index.php?rid=4759100&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21516532%26dopt%3DAbstract Authors: Arslan M, Qin Z, Buehler MJ Intermediate filaments (IFs) are the key components of cytoskeleton in eukaryotic cells and are critical for cell mechanics. The building block of IFs is a coiled-coil alpha-helical dimer, consisting of several domains that include linkers and other structural discontinuities. One of the discontinuities in the dimer's coiled-coil region is the so-called 'stutter' region. The stutter is a region where a variation of the amino acid sequence pattern from other parts of the alpha-helical domains of the protein is found. It was suggested in earlier works that due to this sequence variation, the perfect coiled-coil arrangement ceases to exist. Here, we show using explicit water molecular dynamics and well-tempered metadynamics that for the coil2 domain of... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=4759100 Thu, 28 Apr 2011 10:30:06 +0100 4759100 http://www.medworm.com/index.php?rid=4759120&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21491253%26dopt%3DAbstract Authors: Dal H, Goktepe S, Kaliske M, Kuhl E This work introduces a novel, unconditionally stable and fully coupled finite element method for the bidomain system of equations of cardiac electrophysiology. The transmembrane potential [image omitted]  and the extracellular potential [image omitted]  are treated as independent variables. To this end, the respective reaction-diffusion equations are recast into weak forms via a conventional isoparametric Galerkin approach. The resultant nonlinear set of residual equations is consistently linearised. The method results in a symmetric set of equations, which reduces the computational time significantly compared to the conventional solution algorithms. The proposed method is inherently modular and can be combined with phenomenological or ion... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=4759120 Thu, 31 Mar 2011 23:00:00 +0100 4759120 http://www.medworm.com/index.php?rid=4759119&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21491254%26dopt%3DAbstract Authors: Rauter G, Baumgartner L, Denoth J, Riener R, Wolf P In rowing, motor learning may be facilitated by augmented feedback that displays the ratio between actual mean boat velocity and maximal achievable mean boat velocity. To provide this ratio, the aim of this work was to develop and evaluate an algorithm calculating an individual maximal mean boat velocity. The algorithm optimised the horizontal oar movement under constraints such as the individual range of the horizontal oar displacement, individual timing of catch and release and an individual power-angle relation. Immersion and turning of the oar were simplified, and the seat movement of a professional rower was implemented. The feasibility of the algorithm, and of the associated ratio between actual boat velocity and optimi... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=4759119 Thu, 31 Mar 2011 23:00:00 +0100 4759119 http://www.medworm.com/index.php?rid=4759118&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21491255%26dopt%3DAbstract This study provides a theoretical foundation to elucidate the role of each of these elements in the control of the ISA. A recourse to the principle of virtual work explained through d'Alembert's principle for reducing a dynamics problem to an instantaneous static scenario allows screws to be applied to the biomechanics of human motion. The principle of reciprocity links these approaches together to explain the transmitting load between the tibia and the femur as well as the relative motion within the knee joint. A principal clinical implication of this study is the introduction of the reciprocal connection factor to evaluate knee kinematics and kinetics in one simple term, allowing the quantitative assessment of the outcome of knee-joint treatment and rehabilitation methods. PMID: 2149... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=4759118 Thu, 31 Mar 2011 23:00:00 +0100 4759118 http://www.medworm.com/index.php?rid=4759117&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21491256%26dopt%3DAbstract This study investigates the possibility of introducing computational approximations in modelling stent deployment in aneurysmatic cerebral vessels to achieve simulations compatible with the constraints of real clinical workflows. The release of a self-expandable stent in a simplified aneurysmatic vessel was modelled in four different initial positions. Six progressively simplified modelling approaches (based on Finite Element method and Fast Virtual Stenting - FVS) have been used. Comparing accuracy of the results, the final configuration of the stent is more affected by neglecting mechanical properties of materials (FVS) than by adopting 1D instead of 3D stent models. Nevertheless, the differences showed are acceptable compared to those achieved by considering different stent initial posi... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=4759117 Thu, 31 Mar 2011 23:00:00 +0100 4759117 http://www.medworm.com/index.php?rid=4759116&cid=s_38096_169_f&fid=38096&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21491257%26dopt%3DAbstract In this study, the ROMs in both the knee joint and CPM device during CPM treatment were measured using a motion analysis system for three different CPM devices. Additionally, the trajectories of the angles at the knee for hip joint misalignments were evaluated using kinematic models of the three CPM devices. The results showed that discrepancies in ROM between the knee joints and the CPM device settings during CPM treatment were revealed regardless of the CPM device and that the effect of misalignment is dependent on the design of the CPM device. The present technology could be applied for the development of a better design configuration for the CPM device to reduce the discrepancy in ROM at the knee joint. PMID: 21491257 [PubMed - as supplied by publisher] (Source: Computer Methods in... Computer Methods in Biomechanics and Biomedical Engineering journals http://www.medworm.com/rss/comments.php?id=4759116 Thu, 31 Mar 2011 23:00:00 +0100 4759116