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 'Medical and Biological Engineering and Computing' source. Tue, 07 Feb 2012 07:42:49 +0100 http://www.medworm.com/index.php?rid=5657880&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fv21v56105j084434%2F Abstract  Personalized tumor chemotherapy depends on reliable assay methods, either based on molecular “predictive biomarkers” or on a direct, functional ex vivo assessment of cellular chemosensitivity. As a member of the latter category, a novel high-content platform is described monitoring human mamma carcinoma explants in real time and label-free before, during and after an ex vivo modeled chemotherapy. Tissue explants are sliced with a vibratome and laid into the microreaction chambers of a 24-well sensor test plate. Within these ≈23 μl volume chambers, sensors for pH and dissolved oxygen record rates of cellular oxygen uptake and extracellular acidification. Robot-controlled fluid system and incubation are parts of the tissue culture maintenance system whil... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5657880 Mon, 30 Jan 2012 16:06:57 +0100 5657880 http://www.medworm.com/index.php?rid=5657881&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2F88474553k8p46107%2F In this study, patient-specific analyses were performed to explore the feasibility of TAVI in morphologies, which are currently borderline cases for a percutaneous approach. Five patients were recruited: four patients with failed bioprosthetic aortic valves (stenosis) and one patient with an incompetent, native aortic valve. Three-dimensional models of the implantation sites were reconstructed from computed tomography images. Within these realistic geometries, TAVI with an Edwards Sapien stent was simulated using finite element (FE) modelling. Engineering and clinical outcomes were assessed. In all patients, FE analysis proved that TAVI was morphologically feasible. After the implantation, stress distribution showed no risks of immediate device failure and geometric orifice areas inc... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5657881 Sun, 29 Jan 2012 06:36:48 +0100 5657881 http://www.medworm.com/index.php?rid=5636761&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2F67643317447k6430%2F This study contributes to the interpretation of previous clinical observations, and illustrates how computer modeling provides a complementary approach to study the mechanisms of cardiac arrhythmias. Content Type Journal ArticleCategory Original ArticlePages 1-9DOI 10.1007/s11517-011-0859-3Authors Laurent Uldry, Applied Signal Processing Group, Swiss Federal Institute of Technology, EPFL-STI-SCI-JMV, Bâtiment ELD, Station 11, 1015 Lausanne, SwitzerlandVincent Jacquemet, Department of Physiology, Université de Montréal, Montréal, CanadaNathalie Virag, Medtronic Europe, Tolochenaz, SwitzerlandLukas Kappenberger, University of Lausanne, Lausanne, SwitzerlandJean-Marc Vesin, Applied Signal Processing Group, Swiss Federal Institute of Technology, EPFL-STI-SCI-JMV, Bâtiment ELD, Sta... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5636761 Tue, 24 Jan 2012 07:19:28 +0100 5636761 http://www.medworm.com/index.php?rid=5626115&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fy7038526x012u169%2F In conclusion, bruise behavior depends non-intuitively on the initial blood pool properties; hence, a model that includes shape, area and concentration distribution at onset is indispensable. Future age determination, including inhomogeneous hemoglobin distributions, will likely be based on the presented method for gaussian distributions. Content Type Journal ArticleCategory Original ArticlePages 1-7DOI 10.1007/s11517-012-0860-5Authors Barbara Stam, Biomedical Engineering and Physics, Academic Medical Centre, P.O. Box 22660, 1100 DD Amsterdam, The NetherlandsMartin J. C. van Gemert, Biomedical Engineering and Physics, Academic Medical Centre, P.O. Box 22660, 1100 DD Amsterdam, The NetherlandsTon G. van Leeuwen, Biomedical Engineering and Physics, Academic Medical Centre, P.O. Box... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5626115 Fri, 20 Jan 2012 07:46:58 +0100 5626115 http://www.medworm.com/index.php?rid=5626116&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fr113004188gt1074%2F Abstract  The grasping instruments used in minimally invasive surgery reduce the ability of the surgeon to feel the forces applied on the tissue, thereby complicating the handling of the tissue and increasing the risk of tissue damage. Force sensors implemented in the forceps of the instruments enable accurate measurements of applied forces, but also complicate the design of the instrument. Alternatively, indirect estimations of tissue interaction forces from measurements of the forces applied on the handle are prone to errors due to friction in the linkages. Further, the force transmission from handle to forceps exhibits large nonlinearities, so that extensive calibration procedures are needed. The kinematic analysis of the grasping mechanism and experimental results prese... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5626116 Thu, 19 Jan 2012 06:57:04 +0100 5626116 http://www.medworm.com/index.php?rid=5626117&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2F1054n135616q8784%2F Abstract  Measuring the rate of finger tapping is a technique commonly used as an indicator of impairment in degenerative neurological conditions, such as Huntington’s disease. The information it provides can be greatly enhanced by analysing not simply the overall tapping rate, but also the statistical characteristics of the individual times between each successive response. Recent technological improvements in the recording equipment allow the responses to be analysed extremely quickly, and permit modification of the task in the interest of greater clinical specificity. Here we illustrate its use with some pilot data from a group of manifest HD patients and age-matched controls. Even in this small cohort, differences in the responses are apparent that appear to relate to... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5626117 Thu, 19 Jan 2012 06:57:03 +0100 5626117 http://www.medworm.com/index.php?rid=5618241&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fj16w85881417274g%2F Abstract  P300 is a positive event-related potential used by P300-brain computer interfaces (BCIs) as a means of communication with external devices. One of the main requirements of any P300-based BCI is accuracy and time efficiency for P300 extraction and detection. Among many attempted techniques, independent component analysis (ICA) is currently the most popular P300 extraction technique. However, since ICA extracts multiple independent components (ICs), its use requires careful selection of ICs containing P300 responses, which limits the number of channels available for computational efficiency. Here, we propose a novel procedure for P300 extraction and detection using constrained independent component analysis (cICA) through which we can directly extract only P300-rele... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5618241 Tue, 17 Jan 2012 07:19:30 +0100 5618241 http://www.medworm.com/index.php?rid=5557431&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fp007x7jn3l281638%2F This study aims to show possible solutions. First, we used time-coded motor imagery (MI) with only one pattern. Second, we reduced the training time by recording only 20 trials of active MI to set up a BCI classifier. Third, we investigated a way to record error potentials (ErrPs) during continuous feedback. Ten subjects controlled an artificial arm by performing MI over target time periods between 1 and 4 s. The subsequent movement of this arm served as continuous feedback. Discrete events, which are required to elicit ErrPs, were added by mounting blinking LEDs on top of the continuously moving arm to indicate the future movements. Time epochs after these events were used to evaluate ErrPs offline. The achieved error rate for the arm movement was on average 26.9%. Obtained ErrPs lo... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5557431 Sat, 31 Dec 2011 16:47:26 +0100 5557431 http://www.medworm.com/index.php?rid=5557432&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fv783nx6113834878%2F Abstract  Laser speckle contrast imaging (LSCI) is a recent clinical powerful tool to obtain full-field images of microvascular blood perfusion. The technique relies on laser speckle obtained by the interactions between coherent monochromatic radiations and the tissues under study. From these speckle images, contrast values are determined and instantaneous map of the perfusion are computed. LSCI has gained increased attention in the last years and is now additional to laser Doppler flowmetry (LDF). In spite of the growing interest for LSCI in skin clinical research, very few LSCI perfusion data processing have been published from now to extract physiologically-linked indices. By opposition, numerous signal processing works have been dedicated to the processing of LDF signal... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5557432 Thu, 29 Dec 2011 06:43:59 +0100 5557432 http://www.medworm.com/index.php?rid=5557433&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fj263h5m0p52mj172%2F Abstract  Parameter identification methods are used to find optimal parameter values to fit models to measured data. The single integral method was defined as a simple and robust parameter identification method. However, the method did not necessarily converge to optimum parameter values. Thus, the iterative integral method (IIM) was developed. IIM will be compared to a proprietary nonlinear-least-squares-based Levenberg–Marquardt parameter identification algorithm using a range of reasonable starting values. Performance is assessed by the rate and accuracy of convergence for an exemplar two parameters insulin pharmacokinetic model, where true values are known a priori. IIM successfully converged to within 1% of the true values in all cases with a median time of 1.23&nbsp... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5557433 Wed, 28 Dec 2011 16:44:34 +0100 5557433 http://www.medworm.com/index.php?rid=5557434&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fj64758674508g433%2F In this study a numerical analysis and in vivo experiments were performed. Regarding the numerical models, the maximum forces occurred in the middle of the elliptical wound in all cases. In the case of highest pre-stress used in these analyses the maximal force varied from 0.5 N for the smallest wound (30 × 5 mm) to 1.5 N for the largest wound (30 × 15 mm). The maximum peak force for the wound with a size of 46 × 13 mm was 3.2 N. The minimum peak force for the wound with a size of 36 × 5 mm was 1.1 N. Content Type Journal ArticleCategory Original ArticlePages 1-6DOI 10.1007/s11517-011-0857-5Authors Lukas Capek, Department of Applied Mechanics, Technical University of Liberec, Studentska 2, 461 17... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5557434 Tue, 27 Dec 2011 06:34:09 +0100 5557434 http://www.medworm.com/index.php?rid=5542909&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fr811j0114575lh04%2F Abstract  Current complication rates for adolescent scoliosis surgery necessitate the development of better surgical planning tools to improve outcomes. Here we present our approach to developing finite element models of the thoracolumbar spine for deformity surgery simulation, with patient-specific model anatomy based on low-dose pre-operative computed tomography scans. In a first step towards defining patient-specific tissue properties, an initial ‘benchmark’ set of properties were used to simulate a clinically performed pre-operative spinal flexibility assessment, the fulcrum bending radiograph. Clinical data for ten patients were compared with the simulated results for this assessment and in cases where these data differed by more than 10%, soft tissue properties fo... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5542909 Sat, 24 Dec 2011 16:45:55 +0100 5542909 http://www.medworm.com/index.php?rid=5542910&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fd222503885k40872%2F Abstract  The diagnosis of sleep-disordered breathing (SDB) usually relies on the analysis of complex polysomnographic measurements performed in specialized sleep centers. Automatic signal analysis is a promising approach to reduce the diagnostic effort. This paper addresses SDB and sleep assessment solely based on the analysis of a single-channel ECG recorded overnight by a set of signal analysis modules. The methodology of QRS detection, SDB analysis, calculation of ECG-derived respiration curves, and estimation of a sleep pattern is described in detail. SDB analysis detects specific cyclical variations of the heart rate by correlation analysis of a signal pattern and the heart rate curve. It was tested with 35 SDB-annotated ECGs from the Apnea-ECG Database, and achieved a... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5542910 Fri, 23 Dec 2011 06:49:18 +0100 5542910 http://www.medworm.com/index.php?rid=5542911&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fv6h678p17p677617%2F Abstract  Here, we consider the issue of generating a suitable controlled environment for the evaluation of phase contrast (PC) MRI measurements. The computational framework, tailored to build synthetic datasets, is based on a two-step approach, i.e., define and implement (1) an accurate CFD model and (2) an image generator able to mime the overall outcomes of a PC MRI acquisition starting from datasets retrieved by the computational model. About 20 different datasets were built by changing relevant image parameters (pixel size, slice thickness, time frames per cardiac cycle). Focusing our attention on the thoracic aorta, synthetic images were processed in order to: (1) verify to which extent the fluid dynamics into the aortic arch is influenced by the image parameters; (2)... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5542911 Thu, 22 Dec 2011 12:51:58 +0100 5542911 http://www.medworm.com/index.php?rid=5542912&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2F8n7l78n655739044%2F This study investigated the wear phenomena of chamfered acetabular cup liners. The liners have three parameters at the lengthened rim: the length of the elongation, the depth of the cup and the chamfer angle. Using published wear volume equations for cylindrically elongated liners, this study analysed the volume of the chamfer to obtain the exact theoretical wear volume of the chamfered liner. The criteria described in our previous paper were used to verify the accuracy of the proposed methodology. The results showed that a shallow cup depth (<2 mm) and a chamfer angle of about 30° could significantly reduce the wear volume arising from the elongation. When the chamfer angle was increased further, this effect became progressively less significant. The results suggest that a ... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5542912 Wed, 21 Dec 2011 20:07:36 +0100 5542912 http://www.medworm.com/index.php?rid=5542913&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fx187h8345646q753%2F This study presents EIS of retinal pigment epithelial (RPE) cell model of the putative RPE differentiated from human embryonic stem cells (hESC-RPE). The generally utilized RPE cell model, ARPE-19, was used as immature control. The measured EIS was analyzed by fitting an equivalent electrical circuit model describing the resistive and capacitive properties of the RPE. Our results indicated that TER of hESC-RPE cells was close to the values of human RPE presented in the literature. This provides evidence that the stem cell-derived RPE in vitro can reach high-barrier function. Furthermore, hESC-RPE cells produced impedance spectra that can be modeled by the equivalent circuit of one time constant. ARPE-19 cells produced low-barrier properties, that is, an impedance spectra that suggest... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5542913 Wed, 21 Dec 2011 20:07:35 +0100 5542913 http://www.medworm.com/index.php?rid=5521809&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fw228658401471717%2F Abstract  Many of the aches and pains of adults are the result of the long-term effects of bad posture or body misalignment. Postural kyphosis in adolescence, which is an excessive rounding of the upper spine, may be one of the effects of poor standing and sitting habits. A smart garment, consisting of a harness and two data-sensor loggers, was developed to monitor and provide vibration feedback to wearers to improve their posture during daily activities. Laboratory tests verified that the garment could provide an accuracy of 2 ± 2° during static measurement and 3 ± 2° during stable or slowly changing posture activities and 4 ± 4° during rapidly changing posture activities. Four volunteers wore the system for 3 h per day and for 4 con... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5521809 Sat, 17 Dec 2011 17:04:09 +0100 5521809 http://www.medworm.com/index.php?rid=5521810&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2F615jk47356181874%2F Abstract  While aortic valve root compliance and leaflet coaptation have significant influence on valve closure, their implications have not yet been fully evaluated. The present study developed a full fluid–structure interaction (FSI) model that is able to cope with arbitrary coaptation between the leaflets of the aortic valve during the closing phase. Two simplifications were also evaluated for the simulation of the closing phase only. One employs an FSI model with a rigid root and the other uses a “dry” (without flow) model. Numerical tests were performed to verify the model. New metrics were defined to process the results in terms of leaflet coaptation area and contact pressure. The axial displacement of the leaflets, closure time and coaptation parameters were si... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5521810 Thu, 15 Dec 2011 06:43:30 +0100 5521810 http://www.medworm.com/index.php?rid=5455208&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fh82l1w4537082g6m%2F Abstract  Aspirin-induced asthma (AIA) is a severe inflammatory disease, which affects aspirin-intolerant patients after ingestion of aspirin or other non-steroidal anti-inflammatory drugs (NSAIDs). In this article, a mathematical model describing arachidonic acid metabolism and its interaction with NSAIDs, is used to study the strategy for safe managing of NSAIDs to AIA patients. Three different AIA patient populations are taken into consideration. First, the values of aspirin and ibuprofen limiting doses that might induce symptoms of AIA are calculated and compared to experimentally observed threshold doses to enlighten which AIA patient population is susceptible to aspirin and ibuprofen. Second, the methodology of NSAID administration is studied on AIA populations suscep... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5455208 Sat, 26 Nov 2011 06:40:10 +0100 5455208 http://www.medworm.com/index.php?rid=5455209&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fj78567024p916602%2F The objective of this study was to evaluate a computerized model-based DSS for its advice on inspired oxygen fraction, tidal volume and respiratory frequency. The DSS was retrospectively evaluated in 16 intensive care patient cases, with physiological models fitted to the retrospective data and then used to simulate patient response to changes in therapy. Sensitivity of the DSS’s advice to variations in cardiac output (CO) was evaluated. Compared to the baseline ventilator settings set as part of routine clinical care, the system suggested lower tidal volumes and inspired oxygen fraction, but higher frequency, with all suggestions and the model simulated outcome comparing well with the respiratory goals of the Acute Respiratory Distress Syndrome Network from 2000. Changes in advice... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5455209 Tue, 22 Nov 2011 06:56:56 +0100 5455209 http://www.medworm.com/index.php?rid=5429354&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2F950t81h67n655270%2F Abstract  The aim was to quantify the influence of heterogeneous isotropic and heterogeneous anisotropic tissue on the spatial distribution of the electric field during deep brain stimulation (DBS). Three finite element tissue models were created of one patient treated with DBS. Tissue conductivity was modelled as (I) homogeneous isotropic, (II) heterogeneous isotropic based on MRI, and (III) heterogeneous anisotropic based on diffusion tensor MRI. Modelled DBS electrodes were positioned in the subthalamic area, the pallidum, and the internal capsule in each tissue model. Electric fields generated during DBS were simulated for each model and target-combination and visualized with isolevels at 0.20 (inner), and 0.05 V mm−1 (outer). Statistical and vector analysis ... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5429354 Fri, 18 Nov 2011 17:33:45 +0100 5429354 http://www.medworm.com/index.php?rid=5429355&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fq76882n12287g173%2F In this study, we compared four models to derive coronary plasma volume using indicator dilution; the mono-exponential, power-law, gamma-variate, and local density random walk (LDRW) model. In anesthetized goats (N = 14), we determined the distribution volume of high molecular weight (2,000 kDa) dextrans. A bolus injection (1.0 ml, 0.65 mg/ml) was given intracoronary and coronary venous blood samples were taken every 0.5–1.0 s; outflow curves were analyzed using the four aforementioned models. Measurements were done at baseline and during adenosine infusion. Absolute coronary plasma volume estimates varied by ~25% between models, while the relative volume increase during adenosine infusion was similar for all models. The gamma-variate, LDRW, and mono-e... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5429355 Fri, 18 Nov 2011 06:57:51 +0100 5429355 http://www.medworm.com/index.php?rid=5429356&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fy132j2j25488p1m1%2F Content Type Journal ArticleCategory EditorialPages 1-2DOI 10.1007/s11517-011-0846-8Authors Jos A. E. Spaan, Department of Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, P.O. Box 22700, 1100 DE Amsterdam, The Netherlands Journal Medical and Biological Engineering and ComputingOnline ISSN 1741-0444Print ISSN 0140-0118 (Source: Medical and Biological Engineering and Computing) Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5429356 Fri, 18 Nov 2011 06:57:50 +0100 5429356 http://www.medworm.com/index.php?rid=5405179&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Ffk24353p4p23xu32%2F Abstract  Microdialysis can be used in parallel to deep brain stimulation (DBS) to relate biochemical changes to the clinical outcome. The aim of the study was to use the finite element method to predict the tissue volume of influence (TVImax) and its cross-sectional radius (r TVImax) when using brain microdialysis, and visualize the TVImax in relation to patient anatomy. An equation based on Fick’s law was used to simulate the TVImax. Factorial design and regression analysis were used to investigate the impact of the diffusion coefficient, tortuosity and loss rate on the r TVImax. A calf brain tissue experiment was performed to further evaluate these parameters. The model was implemented with pre-(MRI) and post-(CT) operative patient images for simulation of the TVImax fo... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5405179 Sat, 12 Nov 2011 16:54:11 +0100 5405179 http://www.medworm.com/index.php?rid=5378217&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fp5744282363j6276%2F This study is an update on the developments of the model over the last decade including a qualitative validation of the different simulation architectures available in the DSEM. To validate the model, a dynamic forward flexion motion was performed by one subject, of which the motion data and surface EMG-signals of 12 superficial muscles were measured. Patterns of the model-predicted relative muscle forces were compared with their normalized EMG-signals. Results showed relatively good agreement between forces and EMG (mean correlation coefficient of 0.66). However, for some cases, no force was predicted while EMG activity had been measured (false-negatives). The DSEM has been used and has the potential to be used in a variety of clinical and biomechanical applications. Content Ty... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5378217 Sat, 29 Oct 2011 05:41:40 +0100 5378217 http://www.medworm.com/index.php?rid=5378218&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fn74m644161806047%2F This study aimed at developing a fully automated bone segmentation method for the human knee (femur and tibia) from magnetic resonance (MR) images. MR imaging was acquired on a whole body 1.5T scanner with a gradient echo fat suppressed sequence using an extremity coil. The method was based on the Ray Casting technique which relies on the decomposition of the MR images into multiple surface layers to localize the boundaries of the bones and several partial segmentation objects being automatically merged to obtain the final complete segmentation of the bones. Validation analyses were performed on 161 MR images from knee osteoarthritis patients, comparing the developed fully automated to a validated semi-automated segmentation method, using the average surface distance (ASD), volume co... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5378218 Sat, 29 Oct 2011 05:41:39 +0100 5378218 http://www.medworm.com/index.php?rid=5378219&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2F3466xl0u43640kj6%2F Abstract  To investigate the effects of meniscectomy on degenerative osteoarthritis, a three-dimensional (3D) finite element (FE) model of the human lower limb is constructed from a combination of magnetic resonance (MR) images and computed tomographic (CT) images that can provide anatomically suitable boundary conditions for a knee joint. Four cases, i.e., the intact meniscus, and the partial, sub-total, and total meniscectomy of the medial meniscus are modeled and simulated. We consider that the cartilage-to-cartilage contact area and the peak contact pressure in the meniscus may be significant parameters in evaluating degenerative osteoarthritis. Partial meniscectomy can be regarded as a better treatment than sub-total/total meniscectomy, and a high possibility of degene... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5378219 Fri, 28 Oct 2011 17:23:30 +0100 5378219 http://www.medworm.com/index.php?rid=5378220&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fm1q20t06702724r7%2F Abstract  The solution of the mixed boundary value problem of potential theory involves the computation of the potential field generated by monolayer and double layer source distributions on surfaces at which boundary conditions are known. Closed-form analytical expressions have been described in the literature for the potential field generated by double layers having a linearly distributed strength over triangular source elements. This contribution presents the corresponding expression for the linearly distributed monolayer strength. The solution is shown to be valid for all observation points in space, including those on the interior, edges and vertices of the source triangle. Content Type Journal ArticleCategory Original ArticlePages 1-9DOI 10.1007/s11517-011-0837-9A... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5378220 Fri, 28 Oct 2011 05:48:44 +0100 5378220 http://www.medworm.com/index.php?rid=5294742&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Ff622u735176g351m%2F This study showed that Dp stress, with or without hypoperfusion, had a clear effect on myocyte electrophysiology, expressed by consistent ECG amplitude changes, detected by the EVC method. The EVC method did not distinguish between NS and patients in this clinical setting. Content Type Journal ArticleCategory Original ArticlePages 1-10DOI 10.1007/s11517-011-0835-yAuthors Guy Dori, Department of Internal Medicine C, The Lady Davis Carmel Medical Center, Haifa, IsraelMichal Gershinsky, Department of Internal Medicine C, The Lady Davis Carmel Medical Center, Haifa, IsraelSimona Ben-Haim, Institute of Nuclear Medicine, The Lady Davis Carmel Medical Center, Haifa, IsraelBasil S. Lewis, Department of Cardiology, The Lady Davis Carmel Medical Center, Haifa, IsraelHaim Bitterman, Departme... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5294742 Tue, 04 Oct 2011 05:52:42 +0100 5294742 http://www.medworm.com/index.php?rid=5282839&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fl1r8n0t7pg3024u8%2F Content Type Journal ArticleCategory EditorialPages 1-3DOI 10.1007/s11517-011-0836-xAuthors Nicolas Garcia, Universidad Miguel Hernandez, Elche, Alicante, SpainJose M. Sabater-Navarro, Universidad Miguel Hernandez, Elche, Alicante, SpainE. Gugliemeli, Universita Campus bio-medico di Roma, Rome, ItalyA. Casals, Universitat Politecnica de Catalunya, Barcelona, Spain Journal Medical and Biological Engineering and ComputingOnline ISSN 1741-0444Print ISSN 0140-0118 (Source: Medical and Biological Engineering and Computing) Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5282839 Fri, 30 Sep 2011 05:49:34 +0100 5282839 http://www.medworm.com/index.php?rid=5282840&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fu8615111140113m1%2F Abstract  The main objective of this article is to implement and compare QRS subtraction techniques for intra-cardiac atrial electrograms based on using the surface ECG as a reference. A band-pass filter between 8 and 20 Hz followed by rectification, and then a low-pass filter at 6 Hz are used for QRS detection. QRS subtraction was performed using three different approaches: flat, linear and spline interpolations. QRS subtraction affects the power of the signals but it normally does not affect the dominant frequency. The average power of the atrial electrograms after QRS subtraction is significantly reduced for frequencies above 10 Hz. Content Type Journal ArticleCategory Original ArticlePages 1-8DOI 10.1007/s11517-011-0829-9Authors A. Ahmad, Department... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5282840 Fri, 30 Sep 2011 05:49:33 +0100 5282840 http://www.medworm.com/index.php?rid=5271013&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fvm0151717rj06811%2F We report on two new physiological phenomena: the long-term and total heart rate asymmetry, which describe a significantly larger contribution of heart rate accelerations to long-term and total heart rate variability. In addition to the existing pair of indices, \text SD1d, \text SD1a, which are based on partitioning short-term variance, we introduce two other pairs of descriptors based on partitioning long-term ( \text SD2d, \text SD2a ) and total ( \text SDNNd, \text SDNNa ) heart rate variability. The new asymmetric descriptors are used to analyze RR intervals time series derived from the 30-min ECG recordings of 241 healthy subjects resting in supine position. It is shown that both new types of asymmetry are present in 76% of the subjects. The new ... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5271013 Wed, 28 Sep 2011 05:49:10 +0100 5271013 http://www.medworm.com/index.php?rid=5271015&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2F80575m7m485w3523%2F Abstract  Automated robotic bio-micromanipulation can improve the throughput and efficiency of single-cell experiments. Adherent cells, such as fibroblasts, include a wide range of mammalian cells and are usually very thin with highly irregular morphologies. Automated micromanipulation of these cells is a beneficial yet challenging task, where the machine vision sub-task is addressed in this article. The necessary but neglected problem of localizing injection sites on the nucleus and the cytoplasm is defined and a novel two-stage model-based algorithm is proposed. In Stage I, the gradient information associated with the nucleic regions is extracted and used in a mathematical morphology clustering framework to roughly localize the nucleus. Next, this preliminary segmentation... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5271015 Tue, 27 Sep 2011 05:53:01 +0100 5271015 http://www.medworm.com/index.php?rid=5271014&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fg8l590418672mk04%2F This article investigates in detail the practical performance of different implementations of the compressive sensing theory when applied to scalp EEG signals. Content Type Journal ArticleCategory Special Issue - Original ArticlePages 1-9DOI 10.1007/s11517-011-0832-1Authors Amir M. Abdulghani, Department of Electrical and Electronic Engineering, Imperial College London, London, SW7 2AZ UKAlexander J. Casson, Department of Electrical and Electronic Engineering, Imperial College London, London, SW7 2AZ UKEsther Rodriguez-Villegas, Department of Electrical and Electronic Engineering, Imperial College London, London, SW7 2AZ UK Journal Medical and Biological Engineering and ComputingOnline ISSN 1741-0444Print ISSN 0140-0118 (Source: Medical and Biological Engineering and Computi... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5271014 Tue, 27 Sep 2011 05:53:01 +0100 5271014 http://www.medworm.com/index.php?rid=5258293&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2F4544705l258k6027%2F In this study, we focused on different variants of AR models and compare performance with logBP features. In particular, we analyzed univariate, vector, and bilinear AR models. We used four-class motor imagery data from nine healthy users over two sessions. We used the first session to optimize parameters such as model order and frequency bands. We then evaluated optimized feature extraction methods on the unseen second session. We found that band power yields significantly higher classification accuracies than AR methods. However, we did not update the bias of the classifiers for the second session in our analysis procedure. When updating the bias at the beginning of a new session, we found no significant differences between all methods anymore. Furthermore, our results indicate tha... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5258293 Sat, 24 Sep 2011 15:44:40 +0100 5258293 http://www.medworm.com/index.php?rid=5258294&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fu602tk708r164421%2F This study aims to calibrate the mechanical properties of a vertebral body FEM using an inverse method based on experiments performed at slow and fast dynamic loading conditions. A detailed FEM of a human lumbar vertebral body (23,394 elements) was developed and tested under compression at 2,500 and 10 mm s−1. A central composite design was used to adjust the mechanical properties (Young modulus, yield stress, and yield strain) while optimizing four criteria (ultimate strain and stress of cortical and trabecular bone) until the failure load and energy at failure reached experimental results from the literature. At 2,500 mm s−1, results from the calibrated simulation were in good agreement with the average experimental data (1.5% difference for the failure load ... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5258294 Sat, 24 Sep 2011 15:44:39 +0100 5258294 http://www.medworm.com/index.php?rid=5258295&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2F5235327900601665%2F In this study, both methods were utilised using bovine cadavers. Twenty four samples of cancellous bone were extracted from fresh bovine and the samples were cleaned from excessive marrow. Uniaxial compression testing was performed with displacement control. After mechanical testing, each specimen was ashed in a furnace. Four of the samples were exemplarily scanned using micro-computed tomography (μCT) and three dimensional models of the cancellous bones were reconstructed for finite element simulation. The mechanical properties and the failure modes obtained from numerical simulations were then compared to the experiments. Correlations between microarchitectural parameters to the mechanical properties and failure modes were then made. The Young’s modulus correlates well with the ... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5258295 Fri, 23 Sep 2011 15:46:39 +0100 5258295 http://www.medworm.com/index.php?rid=5258296&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2F4t45672842hmjg40%2F This report describes a computer-assisted method for 3-D planning and realizing a single-cut rotational osteotomy with a patient-specific cutting guide for orienting the osteotomy and an angled jig for adjusting the rotation angle. The accuracy and reproducibility of the method is evaluated experimentally using plastic bones. In addition, complex rotational deformities are simulated by a computer to investigate the relation between deformity and correction parameters. The computed relation between deformity and correction parameters enables the surgeon to judge the feasibility of a single-cut rotational osteotomy. This appears possible for deformities combining axial misalignment with sufficient axial rotation. The proposed 3-D method of preoperative planning and transfer with a pati... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5258296 Fri, 23 Sep 2011 15:46:38 +0100 5258296 http://www.medworm.com/index.php?rid=5235454&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fv465554496p34tl3%2F The objective of this study is to assess the relative impact of material properties and of loading conditions on vertebral strength using a finite element model. Fourteen subject-specific vertebral finite element models were used to investigate the effect of material properties and loading conditions. A design of experiment was set to study three parameters: Young’s moduli of trabecular bone and cortico-trabecular bone (outer 3 mm of the vertebra), and load location. Cortico-trabecular bone modulus variation from 270 to 478 MPa made fracture load vary from 22 to 51%, depending on other parameters. Trabecular bone modulus variation from 115 to 258 MPa made fracture load vary from 11 to 43%. Displacing load location by 1 cm resulted in a mean decrease of 48–60% ... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5235454 Fri, 16 Sep 2011 16:42:58 +0100 5235454 http://www.medworm.com/index.php?rid=5235455&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Ft41wn0478x63vp50%2F This article compares the determination of body fat-free-mass (FFM) by impedance, using either hand-to-foot resistance (R13) or foot-to-foot one (R34) from comparison with dual X-ray absorptiometry (DXA) measurements in a normal population. The first goal was to see if the foot-to-foot resistance used in body fat analysers provides less accurate information for body FFM than the hand-to-foot one used by medical impedance-meters. Another goal was to compare the prediction accuracy of six different regression equations of FFM for each sex and for each resistance relatively to DXA. The impedancemeter used in this study was a Tefal prototype with 4 plantar electrodes and 4 additional electrodes for the hands and providing hand-to-foot and foot-to-foot resistances. Coefficients of these co... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5235455 Wed, 14 Sep 2011 05:51:24 +0100 5235455 http://www.medworm.com/index.php?rid=5191968&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fu91136188u247685%2F Abstract  In this article, we propose a new method for providing assistance during cyclical movements. This method is trajectory-free, in the sense that it provides user assistance irrespective of the performed movement, and requires no other sensing than the assisting robot’s own encoders. The approach is based on adaptive oscillators, i.e., mathematical tools that are capable of learning the high level features (frequency, envelope, etc.) of a periodic input signal. Here we present two experiments that we recently conducted to validate our approach: a simple sinusoidal movement of the elbow, that we designed as a proof-of-concept, and a walking experiment. In both cases, we collected evidence illustrating that our approach indeed assisted healthy subjects during movemen... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5191968 Wed, 31 Aug 2011 15:53:26 +0100 5191968 http://www.medworm.com/index.php?rid=5191967&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2F447k282451w06511%2F This article presents a novel evaluation system along with methods to evaluate bilateral coordination of arm function on activities of daily living tasks before and after robot-assisted therapy. An affordable bilateral assessment system (BiAS) consisting of two mini-passive measuring units modeled as three degree of freedom robots is described. The process for evaluating functional tasks using the BiAS is presented and we demonstrate its ability to measure wrist kinematic trajectories. Three metrics, phase difference, movement overlap, and task completion time, are used to evaluate the BiAS system on a bilateral symmetric (bi-drink) and a bilateral asymmetric (bi-pour) functional task. Wrist position and velocity trajectories are evaluated using these metrics to provide insight into ... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5191967 Wed, 31 Aug 2011 15:53:26 +0100 5191967 http://www.medworm.com/index.php?rid=5191969&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2F861x45647m215xx2%2F Abstract  The purpose of this study was to develop a rapid and fully automatic method for the assessment of microvascular density and perfusion in sidestream dark field (SDF) images. We modified algorithms previously developed by our group for microvascular density assessment and introduced a new method for microvascular perfusion assessment. To validate the new algorithm for microvascular density assessment, we reanalyzed a selection of SDF video clips (n = 325) from a study in intensive care patients and compared the results to (semi-)manually found microvascular densities. The method for microvascular perfusion assessment (temporal SDF image contrast analysis, tSICA) was tested in several video simulations and in one high quality SDF video clip where the microci... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5191969 Tue, 30 Aug 2011 15:59:34 +0100 5191969 http://www.medworm.com/index.php?rid=5174461&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2F1877849840ph2260%2F This study evaluated the influence of IFS on gait pattern in patients with knee OA. Twenty patients with knee OA walked in a gait laboratory on IFS and control shoes (CSs). An optoelectronic system and force plate were used to perform 3D gait analyses. A comparison of temporal-spatial gait parameters, kinematics, and kinetics was made between IFS and CS. Patients wearing IFS showed a decrease in walking velocity and cadence (8%), unchanged stride length, an increase in stance time (13%), stride time (11%) and step width (14%). No differences were found in knee adduction moment or knee kinematics. Small differences were found in foot and ankle kinematics (2–5°), knee transverse moments (5%), ankle frontal (3%) and sagittal moments (1%) and ground reaction force (1–6%). The gait o... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5174461 Thu, 25 Aug 2011 05:44:56 +0100 5174461 http://www.medworm.com/index.php?rid=5158150&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fq8810531033khh05%2F In this study, system feasibility is shown by experiments on five typically developing toddlers and one special needs toddler with spastic cerebral palsy. Children were placed in the bio-driven device and instructed to navigate through a maze. All subjects were able to successfully complete the maze in multiple trials. In addition, two toddlers showed evidence of improved driving skill by completing the maze in shorter times in successive trials on a given testing day. The results suggest that such a device is feasible for purposeful driving. Recommendations are given for the device and protocol redesign for related future testing. Content Type Journal ArticleCategory Special Issue - Original ArticlePages 1-7DOI 10.1007/s11517-011-0820-5Authors Zachary R. Schoepflin, Mechanical... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5158150 Thu, 18 Aug 2011 05:47:54 +0100 5158150 http://www.medworm.com/index.php?rid=5158151&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2F8437841018345017%2F Abstract  A neurobot (NR) is a mechatronic wearable robot that can be applied to drive a paralyzed limb. Through the application of controllable forces, a NR can assist, replace, or retrain a certain motor function. Robotic intervention in rehabilitation of motor disorders has a potential to improve traditional therapeutic interventions. Because of its flexibility, repeatability and quantifiability, NRs have been more and more applied in neurorehabilitation. Furthermore, combination of NRs with functional electrical stimulation/therapy constitutes a trend to overcome a number of practical limitations to widespread the application of NRs in clinical settings and motor control studies. In this review, we examine the motor learning principles, robotic control approaches and no... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5158151 Wed, 17 Aug 2011 05:56:22 +0100 5158151 http://www.medworm.com/index.php?rid=5138385&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fa683tt5240tt7327%2F In this study, a poroelastic model is developed to investigate fluid transport and flow-induced tissue deformation in a tumor during an infusion process. A surface tracking technique is employed to predict the shape of nanofluid spreading after injection. The model is then used to simulate the formation of backflow and the change of tissue porosity due to the deformation. Specifically, we quantify the influence of the backflow on the spreading shape of the nanofluid and its dependence on injection parameters such as infusion rates, needle diameters, and tumor elastic properties. It is found that backflow is an important factor causing an irregular distribution of the nanofluid injected in a tumor. A higher infusion rate, larger needle diameter, and lower elastic modulus yield a longe... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5138385 Sun, 14 Aug 2011 05:45:12 +0100 5138385 http://www.medworm.com/index.php?rid=5130486&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fg168v29p2521541j%2F The objective of this study is to determine how physiological levels of vessel bending and compression following stent implantation will influence the magnitude of stent stresses and hence the risks of fatigue fracture. A further objective is to compare how this mechanical environment will influence arterial stresses following implantation of either stainless steel or nitinol stents. To this end, models of both nitinol and stainless steel stents deployed in peripheral arteries were created, with appropriate loading conditions applied. At high levels of bending and compression, the strain amplitude threshold value for fatigue failure is exceeded for nitinol stents. Bending was predicted to induce high stresses in the artery following stenting, with higher arterial stresses predicted f... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5130486 Thu, 11 Aug 2011 06:56:01 +0100 5130486 http://www.medworm.com/index.php?rid=5125577&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fpx674x3022784836%2F In conclusion, the performance of the synchrogram technique was improved by including an adaptive delay in the cardiac oscillator. Content Type Journal ArticlePages 1-11DOI 10.1007/s11517-011-0822-3Authors Muammar M. Kabir, Centre for Heart Rhythm Disorders, The University of Adelaide, Adelaide, SA 5005, AustraliaDavid A. Saint, Centre for Heart Rhythm Disorders, The University of Adelaide, Adelaide, SA 5005, AustraliaEugene Nalivaiko, School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, NSW 2308, AustraliaDerek Abbott, Centre for Heart Rhythm Disorders, The University of Adelaide, Adelaide, SA 5005, AustraliaMathias Baumert, Centre for Heart Rhythm Disorders, The University of Adelaide, Adelaide, SA 5005, Australia Journal Medical and Biological E... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5125577 Wed, 10 Aug 2011 15:44:09 +0100 5125577 http://www.medworm.com/index.php?rid=5125576&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fy271h685782227l1%2F In this study, a methodology for the generation of AA interval series with a desired probability density function and autocorrelation function is presented. The methodology was evaluated on 2000 AA interval series from 20 endocardial recordings. The results showed that synthetic AA series presented the same statistical characteristics as the real AA series, with a correlation higher than 0.94 (P < 0.01) for all measured statistical parameters. In addition, the role of each statistical characteristic of the AA interval series in the ventricular response during AF is examined using a mathematical model of the atrioventricular node. The statistical characteristics of the AA series influenced the position of more probable RR intervals and the shape of the RR histogram, demon... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5125576 Wed, 10 Aug 2011 15:44:09 +0100 5125576 http://www.medworm.com/index.php?rid=5107194&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fl5r85l5uq0q70604%2F This article first reviews the current state-of-art in rehabilitation robotic devices with pneumatic actuation systems reporting main features and control issues of each therapeutic device. Then, a new pneumatic rehabilitation robot for proprioceptive neuromuscular facilitation therapies and for relearning daily living skills: like taking a glass, drinking, and placing object on shelves is described as a case study and compared with the current pneumatic rehabilitation devices. Content Type Journal ArticlePages 1-12DOI 10.1007/s11517-011-0814-3Authors Ricardo Morales, Biomedical Neuroengineering, Universidad Miguel Hernandez, Avd. de la Universidad s/n Edificio Quorum V, Elche, 03202 SpainFrancisco Javier Badesa, Biomedical Neuroengineering, Universidad Miguel Hernandez, Avd. de... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5107194 Sat, 06 Aug 2011 05:45:42 +0100 5107194 http://www.medworm.com/index.php?rid=5077386&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fx175424k37000r20%2F Abstract  In the past decade, several arm rehabilitation robots have been developed to assist neurological patients during therapy. Early devices were limited in their number of degrees of freedom and range of motion, whereas newer robots such as the ARMin robot can support the entire arm. Often, these devices are combined with virtual environments to integrate motivating game-like scenarios. Several studies have shown a positive effect of game-playing on therapy outcome by increasing motivation. In addition, we assume that practicing highly functional movements can further enhance therapy outcome by facilitating the transfer of motor abilities acquired in therapy to daily life. Therefore, we present a rehabilitation system that enables the training of activities of daily l... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5077386 Wed, 27 Jul 2011 15:50:11 +0100 5077386 http://www.medworm.com/index.php?rid=5077387&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fn7088l6025517j23%2F Abstract  This paper is focused on the multimodal analysis of patient performance, carried out by means of robotic technology and wearable sensors, and aims at providing quantitative measure of biomechanical and motion planning features of arm motor control following rehabilitation. Upper-limb robotic therapy was administered to 24 community-dwelling persons with chronic stroke. Performance indices on patient motor performance were computed from data recorded with the InMotion2 robotic machine and a magneto-inertial sensor. Motor planning issues were investigated by means of techniques of motion decomposition into submovements. A linear regression analysis was carried out to study correlation with clinical scales. Robotic outcome measures showed a significant improvement of... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5077387 Tue, 26 Jul 2011 15:57:17 +0100 5077387 http://www.medworm.com/index.php?rid=5077388&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fx18575q840110662%2F This study introduces the concept design and analysis of a robotic system for the assistance and rehabilitation of disabled people. Based on the statistical data of the most common types of disabilities in Spain and other industrialized countries, the different tasks that the device must be able to perform have been determined. In this study, different robots for rehabilitation and assistance previously introduced have been reviewed. This survey is focused on those robots that assist with gait, balance and standing up. The structure of the ROAD robot presents various advantages over these robots, we discuss some of them. The performance of the proposed architecture is analyzed when it performs the sit to stand activity. Content Type Journal ArticlePages 1-11DOI 10.1007/s11517-011... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5077388 Tue, 26 Jul 2011 05:47:04 +0100 5077388 http://www.medworm.com/index.php?rid=5061920&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fj64307m05212281x%2F Abstract  The enhanced heart rate and blood pressure soon after awaking increases cardiac oxygen demand, and has been associated with the high incidence of acute myocardial infarction in the morning. The behavior of cardiac oxygen supply is unknown. We hypothesized that oxygen supply decreases in the morning and to that purpose investigated cardiac oxygen demand and oxygen supply at night and after awaking. We compared hypertensive to normotensive subjects and furthermore assessed whether pressures measured non-invasively and intra-arterially give similar results. Aortic pressure was reconstructed from 24-h intra-brachial and simultaneously obtained non-invasive finger pressure in 14 hypertensives and 8 normotensives. Supply was assessed by Diastolic Time Fraction (DTF, rat... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5061920 Fri, 22 Jul 2011 17:00:12 +0100 5061920 http://www.medworm.com/index.php?rid=5061921&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fr64rkv1p689m5361%2F Abstract  Evidence suggests that maladaptive changes in the cerebral microcirculation may contribute to ischemia in numerous diseases. We sought, therefore, to develop an ex vivo organ culture system to study early changes in cerebral arteriolar structure and function, and to compare associated findings to those for non-cerebral arterioles. Pilot studies revealed that rabbit cerebral arterioles maintained contractility longer when cultured in media containing rabbit-specific plasma rather than fetal bovine serum. Cerebral and skeletal muscle arterioles were cultured in a pressure myograph for 5 days; maximum dilatory and contractile responses were measured at 0, 1, 3, and 5 days. Passive properties were preserved in cerebral arterioles over the entire culture perio... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5061921 Fri, 22 Jul 2011 17:00:10 +0100 5061921 http://www.medworm.com/index.php?rid=5061922&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fh63p0r6177262673%2F Abstract  The aim of this study is to determine the conditions necessary to achieve optimum chest compression (CC) performance during constant peak displacement cardiopulmonary resuscitation (CPR). This was accomplished by first performing a sensitivity analysis on a theoretical constant peak displacement CPR CC model to identify the parameters with the highest sensitivity. Next, the most sensitive parameters were then optimized for net sternum-to-spine compression depth, using a two-variable non-linear least squares method. The theoretical CC model was found to be most sensitive to: thoracic stiffness, maximum sternal displacement, CC rate, and back support stiffness. Based on a two-variable, non-linear least squares analysis to optimize the model for the net sternum-to-sp... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5061922 Fri, 22 Jul 2011 17:00:09 +0100 5061922 http://www.medworm.com/index.php?rid=5061923&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fb41q873638264852%2F This study describes a protocol for the direct manufacturing of a customized titanium mesh using CAD–CAM procedures and rapid prototyping to augment maxillary bone and minimize surgery when severe atrophy or post-oncological deformities are present. Titanium mesh and particulate autogenous plus bovine demineralised bone were planned for patient rehabilitation. Bone augmentation planning was performed using the pre-op CT data set in relation to the prosthetic demands, minimizing the bone volume to augment at the minimum necessary for implants. The containment mesh design was used to prototype the 0.6 mm thickness customized titanium mesh, by direct metal laser sintering. The levels of regenerated bone were calculated using the post-op CT data set, through comparison with the pr... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5061923 Thu, 21 Jul 2011 18:06:46 +0100 5061923 http://www.medworm.com/index.php?rid=5061924&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Ft4u27821lp71650w%2F This article outlines the problems in measuring the impact of an intervention and explores the concept of providing more mechanical assessment techniques and ultimately the possibility of combining the assessment process with aspects of the intervention. Content Type Journal ArticlePages 1-10DOI 10.1007/s11517-011-0799-yAuthors W. S. Harwin, Cybernetics Research Group, School of Systems Engineering, University of Reading, Reading, RG6 6AY UKA. Murgia, Department of Human Movement Sciences, Maastricht University, Maastricht, The NetherlandsE. K. Stokes, Department of Physiotherapy, School of Medicine, Trinity College, Dublin, Ireland Journal Medical and Biological Engineering and ComputingOnline ISSN 1741-0444Print ISSN 0140-0118 (Source: Medical and Biological Engineering a... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5061924 Thu, 21 Jul 2011 18:06:44 +0100 5061924 http://www.medworm.com/index.php?rid=5061925&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fe6224552q6527p64%2F Abstract  Strokes affect thousands of people worldwide leaving sufferers with severe disabilities affecting their daily activities. In recent years, new rehabilitation techniques have emerged such as constraint-induced therapy, biofeedback therapy and robot-aided therapy. In particular, robotic techniques allow precise recording of movements and application of forces to the affected limb, making it a valuable tool for motor rehabilitation. In addition, robot-aided therapy can utilise visual cues conveyed on a computer screen to convert repetitive movement practice into an engaging task such as a game. Visual cues can also be used to control the information sent to the patient about exercise performance and to potentially address psychosomatic variables influencing therapy. ... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5061925 Wed, 20 Jul 2011 12:27:38 +0100 5061925 http://www.medworm.com/index.php?rid=5061927&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2F5j712v4412n48414%2F Abstract  Biopotential measurements are very sensitive to electromagnetic interference (EMI) from power-lines. Interference conditions are mainly imposed by electric-field coupling, whose effects can be described by coupling capacitances. The main of them are the patient-to-ground and the patient-to-power-line capacitances, usually denoted as C B and C P, respectively. A technique to estimate these elements and experimental data obtained in different environmental conditions are presented. It was found that C B ranges from hundreds of pF to nF, and C P from hundredths of pF to few pF. The presented technique also lets it know the small amplifier-to-ground and amplifier-to-power-line capacitances. The knowledge of all these capacitances allows estimating the EMI conditions... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5061927 Tue, 19 Jul 2011 23:45:33 +0100 5061927 http://www.medworm.com/index.php?rid=5061926&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fd3442662452568p6%2F Abstract  An active contour segmentation technique for extracting the intima–media layer of the common carotid artery (CCA) ultrasound images employing semiautomatic region of interest identification and speckle reduction techniques is presented in this paper. An attempt has been made to test the ultrasound images of the carotid artery of different subjects with this contour segmentation based on improved dynamic programming method. It is found that the preprocessing of ultrasound images of the CCA with region identification and despeckleing followed by active contour segmentation algorithm can be successfully used in evaluating the intima–media thickness (IMT) of the normal and abnormal subjects. It is also estimated that the segmentation used in this paper results an ... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5061926 Tue, 19 Jul 2011 23:45:33 +0100 5061926 http://www.medworm.com/index.php?rid=5050012&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2F44u8720j11266440%2F Abstract  We consider the accumulation and formation of lipid droplets in an adipocyte cell. The process incorporates adipose nucleation (adipogenesis) and growth. At later stages, there will be merging of droplets and growth of larger droplets at the expense of the smaller droplets, which will essentially undergo lipolysis. The process is modeled by the use of the Cahn–Hilliard equation, which is mass-conserving and allows the formation of secondary phases in the context of spinodal decomposition. The volume of fluid (VOF) method is used to determine the total area that is occupied by the lipids in a given cross section. Further, we present an algorithm, applicable to all kinds of grids (structured or unstructured) in two spatial dimensions, to count the number of lipid ... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5050012 Fri, 15 Jul 2011 05:52:13 +0100 5050012 http://www.medworm.com/index.php?rid=5050013&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fbn5638857j401128%2F Abstract  The time delay of the baroreflex may be affected by decreased autonomic activity in uremia. To assess the magnitude and the time delay of heart rate response in patients with end-stage renal disease, continuous beat-to-beat intervals (IBI) and systolic blood pressure (SBP) recordings were monitored in hemodialysis (HD) patients (n = 72), in patients after renal transplantation (TX) (n = 41) and in age-matched controls (C) (n = 34). A 2-term prediction model was computed, in which each IBI change was represented as a function of SBP difference values of two immediately preceding beats. Baroreflex slope and the frequency domain variables low frequency (LF) α index, phase shift, and lag time were also calculated. b 1 coefficient, represe... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5050013 Thu, 14 Jul 2011 06:00:32 +0100 5050013 http://www.medworm.com/index.php?rid=5050014&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Ft72180318m067120%2F This study critically explores different implants utilizing a human spine scoliotic finite element model (FEM). Stainless steel (SS) and shape memory alloy (SMA) staples and flexible tethers were modeled and alternatively integrated around the apex of the convexity of the scoliotic model. Stress profiles over vertebral growth plates were obtained. Two years of growth was simulated with non-instrumented and instrumented models, as curvature changes were quantified. Apical asymmetrical stresses in non-instrumented and instrumented scoliotic models with SS staple, flexible tether, and SMA staple were 0.48, 0.48, 0.23, and 0.33 MPa, respectively. Patient data and non-instrumented model progressed from 28° to 62° of thoracic Cobb angle over 2 years. Simulated projected long-te... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5050014 Thu, 14 Jul 2011 06:00:31 +0100 5050014 http://www.medworm.com/index.php?rid=5050015&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fa3vnv104h7376650%2F Abstract  Pathological tremor is manifested as an involuntary oscillation of one or more body parts. Tremor greatly decreases the quality of life and often prevents the patient from performing daily activities. We hypothesized that sensors-driven multichannel electrical stimulation could stabilize affected joints by activating the antagonistic muscles during involuntary activation of agonist muscles and vice versa (out-of-phase stimulation). Here, we present the new system (hardware and software) and the testing of its operation. The hardware consists of a multichannel stimulator and inertial sensors for feedback. The software implements adaptive sensors-driven control for the out-of-phase stimulation. The system was initially applied to healthy persons at the wrist and elb... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5050015 Thu, 14 Jul 2011 06:00:30 +0100 5050015 http://www.medworm.com/index.php?rid=5035999&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2F1172k78k334766p0%2F Abstract  There is growing evidence that femoroacetabular impingement (FAI) is a probable risk factor for the development of early osteoarthritis in the nondysplastic hip. As FAI arises with end range of motion activities, measurement errors related to skin movement might be higher than anticipated when using previously reported methods for kinematic evaluation of the hip. We performed an in vitro validation and reliability study of a noninvasive method to define pelvic and femur positions in end range of motion activities of the hip using an electromagnetic tracking device. Motion data, collected from sensors attached to the bone and skin of 11 cadaver hips, were simultaneously obtained and compared in a global reference frame. Motion data were then transposed in the hip j... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5035999 Wed, 13 Jul 2011 06:13:21 +0100 5035999 http://www.medworm.com/index.php?rid=5036001&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2F17m563536kv76773%2F Abstract  Deficits in fine motor control are a common early symptom in people with Parkinson disease (PD) and may serve as an ideal marker for the response to therapeutic interventions and progression of the disease. The long-term goal of this research is to develop sensitive clinical markers that can be used to accurately assess disease progression and the response to therapeutic interventions. The purpose of this preliminary study was to examine the effects of medication on the attentional demands of precision (Pre) and power (Pow) grips in individuals with PD. In order to assess force control during precision and power grip, we used an instrumented twist-cap device. Performance on the motor task was quantified using peak force levels (PF) and the time to reach peak force... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5036001 Tue, 12 Jul 2011 06:00:29 +0100 5036001 http://www.medworm.com/index.php?rid=5036000&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2F9082874q41h45075%2F In this study, radial basis function neural network (RBFNN) is used to reconstruct the gastric myoelectric activity (GMA) slow wave from finger PPG signal. Finger PPG and GMA (measured using Electrogastrogram, EGG) signals were acquired simultaneously at the sampling rate of 100 Hz from ten healthy subjects. Discrete wavelet transform (DWT) was used to extract slow wave (0–0.1953 Hz) component from the finger PPG signal; this slow wave PPG was used to reconstruct EGG. A RBFNN is trained on signals obtained from six subjects in both fasting and postprandial conditions. The trained network is tested on data obtained from the remaining four subjects. In the earlier study, we have shown the presence of GMA information in finger PPG signal using DWT and cross-correlation metho... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5036000 Tue, 12 Jul 2011 06:00:29 +0100 5036000 http://www.medworm.com/index.php?rid=5007694&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fx570r1v8557q6274%2F In conclusion, a realistic way of integrating gravity in a scoliotic trunk FEM was developed and stresses due to gravity were explicitly computed. This is a valuable improvement for further biomechanical modeling studies of scoliosis. Content Type Journal ArticlePages 1-11DOI 10.1007/s11517-011-0793-4Authors Julien Clin, Department of Mechanical Engineering, École Polytechnique de Montréal, P.O. Box 6079, Station Centre-ville, Montréal, Québec H3C 3A7, CanadaCarl-Éric Aubin, Department of Mechanical Engineering, École Polytechnique de Montréal, P.O. Box 6079, Station Centre-ville, Montréal, Québec H3C 3A7, CanadaNadine Lalonde, Department of Mechanical Engineering, École Polytechnique de Montréal, P.O. Box 6079, Station Centre-ville, Montréal, Québec H3C 3A7, CanadaSt... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=5007694 Mon, 04 Jul 2011 16:20:37 +0100 5007694 http://www.medworm.com/index.php?rid=4997385&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fe333127570xq6033%2F Abstract  Reconstruction of central aortic pressure from a peripheral measurement by a generalized transfer function (genTF) works well at rest and mild exercise at lower heart rates, but becomes less accurate during heavy exercise. Particularly, systolic and pulse pressure estimations deteriorate, thereby underestimating central pressure. We tested individualization of the TF (indTF) by adapting its resonance frequency at the various levels of exercise. In seven males (age 44–57) with coronary artery disease, central and peripheral pressures were measured simultaneously. The optimal resonance frequency was predicted from regression formulas using variables derived from the individual’s peripheral pressure pulse, including a pulse contour estimation of cardiac output (p... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4997385 Thu, 30 Jun 2011 17:49:01 +0100 4997385 http://www.medworm.com/index.php?rid=4992256&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Frm445lq237555102%2F Abstract  Melatonin (C13H16N2O2) has a wide range of functions in the body. When is inappropriately exposed to light at night, human circadian rhythm will be interfered and then melatonin secretion will become abnormal. For nearly three decades great progresses have been achieved in analytic action spectra and melatonin suppression by various light conditions. However, so far few articles focused on the quantitative calculation of melatonin suppression induced by light. In this article, an algorithm is established, in which all the contributions of rods, cones, and intrinsically photosensitive retinal ganglion cells are considered. Calculation results accords with the experimental data in references very well, which indicate the validity of this algorithm. This algorithm ca... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4992256 Wed, 29 Jun 2011 15:50:33 +0100 4992256 http://www.medworm.com/index.php?rid=4992257&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fl1h4ph3438t30443%2F Abstract  Although cardiac resynchronization therapy (CRT) is an effective treatment for chronic systolic heart failure with dyssynchrony, about one-third of patients do not respond favorably. The interaction between the pacing lead and the coronary sinus (CS) branches is of paramount importance for an effective resynchronization. Minor changes in lead position overtime could interfere with CRT mechanics, without affecting even biophysical parameters or ECG morphology. Although late post-implant CS lead dislodgement rate is consistent, lead movements have been little investigated and only with bi-dimensional methods. The aim of this study was (1) to develop a method for quantifying CS lead position in the 3D domain throughout the cardiac cycle and (2) to test it by comparin... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4992257 Tue, 28 Jun 2011 15:51:41 +0100 4992257 http://www.medworm.com/index.php?rid=4992258&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fn4124628125w41m6%2F Abstract  In this article, we propose a method for automated tracking and analysis of vesicle contours in video sequences acquired by phase contrast microscopy. The contour is determined in each frame of the selected video sequence by detecting the transition between the interior and exterior of the vesicle that is reflected in the image intensity gradients. The resulting contour points are represented in the polar coordinate system, i.e., with uniform angular sampling and with coordinates that originate from the vesicle center of mass, enabling the analysis of the vesicle shape and its membrane fluctuations. By analyzing artificial images with known ground-truth contours, the accuracy and precision of the proposed method was estimated to be 34.1 and 26.9 nm for image ... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4992258 Tue, 28 Jun 2011 06:06:05 +0100 4992258 http://www.medworm.com/index.php?rid=4968174&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fj077u4422281491q%2F Abstract  In the present study, we introduce an EEG-based, real-time, cortical functional connectivity imaging system capable of monitoring and tracing dynamic changes in cortical functional connectivity between different regions of interest (ROIs) on the brain cortical surface. The proposed system is based on an EEG-based dynamic neuroimaging system, which is capable of monitoring spatiotemporal changes of cortical rhythmic activity at a specific frequency band by conducting real-time cortical source imaging. To verify the implemented system, we performed three test experiments in which we monitored temporal changes in cortical functional connectivity patterns in various frequency bands during structural face processing, finger movements, and working memory task. We also t... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4968174 Thu, 23 Jun 2011 16:30:14 +0100 4968174 http://www.medworm.com/index.php?rid=4968175&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fam8r62mgt1721k80%2F Abstract  Near-infrared spectroscopy (NIRS) is a non-invasive optical technique that can be used for brain–computer interfaces (BCIs) systems. A common challenge for BCIs is a stable and reliable classification of single-trial data, especially for cognitive (mental) tasks. With antagonistic activation pattern, recently found for mental arithmetic (MA) tasks, an improved online classification for optical BCIs using MA should become possible. For this investigation, we used the data of a previous study where we found antagonistic activation patterns (focal bilateral increase of [oxy-Hb] in the dorsolateral prefrontal cortex in parallel with a [oxy-Hb] decrease in the medial area of the anterior prefrontal cortex) in eight subjects. We used the [oxy-Hb] responses to search f... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4968175 Thu, 23 Jun 2011 16:30:13 +0100 4968175 http://www.medworm.com/index.php?rid=4968176&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2F7j48k4q077k42hl7%2F Abstract  Recently developed techniques allow the analysis of surface EMG in multiple locations over the skin surface (high-density surface electromyography, HDsEMG). The detected signal includes information from a greater proportion of the muscle of interest than conventional clinical EMG. However, recording with many electrodes simultaneously often implies bad-contacts, which introduce large power-line interference in the corresponding channels, and short-circuits that cause near-zero single differential signals when using gel. Such signals are called ‘outliers’ in data mining. In this work, outlier detection (focusing on bad contacts) is discussed for monopolar HDsEMG signals and a new method is proposed to identify ‘bad’ channels. The overall performance of this... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4968176 Wed, 22 Jun 2011 15:57:55 +0100 4968176 http://www.medworm.com/index.php?rid=4902026&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2F66843334083m8r14%2F Abstract  The selection of a mathematical descriptor for the passive arterial mechanical behavior has been long debated in the literature and customarily constrained by lack of pertinent data on the underlying microstructure. Our objective was to analyze the response of carotid artery subjected to inflation/extension with phenomenological and microstructure-based candidate strain-energy functions (SEFs), according to species (rabbit vs. pig) and region (proximal vs. distal). Histological variations among segments were examined, aiming to explicitly relate them with the differential material response. The Fung-type model could not capture the biphasic response alone. Combining a neo-Hookean with a two-fiber family term alleviated this restraint, but force data were poorly ca... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4902026 Mon, 30 May 2011 16:41:20 +0100 4902026 http://www.medworm.com/index.php?rid=4902027&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2F08271t07477101m7%2F This study indicates that the bioimpedance method has potential for the dual-gating in nuclear medicine imaging. The method would minimize the need of additional equipment, is easy for the technologists to use and comfortable for the patients. Content Type Journal ArticlePages 1-9DOI 10.1007/s11517-011-0787-2Authors Tuomas Koivumäki, Department of Clinical Physiology and Nuclear Medicine, Diagnostic Imaging Centre, Kuopio University Hospital, P.O. Box 1777, 70211 Kuopio, FinlandMarko Vauhkonen, Department of Applied Physics, University of Eastern Finland, P.O. Box 1627, 70211 Kuopio, FinlandJyrki T. Kuikka, Department of Clinical Physiology and Nuclear Medicine, Diagnostic Imaging Centre, Kuopio University Hospital, P.O. Box 1777, 70211 Kuopio, FinlandMikko A. Hakulinen, Departmen... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4902027 Fri, 27 May 2011 06:01:18 +0100 4902027 http://www.medworm.com/index.php?rid=4852631&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fp1088x8r73035463%2F This study examined 112,040 pieces of equipment. An average of 38.3% (42,925, range across countries: 0.83–47%) in developing countries was out of service. The three main causes were lack of training, health technology management, and infrastructure. We hope that the findings will help biomedical engineers with their efforts toward effective designs for the developing world and NGO’s with efforts to design effective healthcare interventions. Content Type Journal ArticlePages 1-4DOI 10.1007/s11517-011-0786-3Authors Lora Perry, Developing World Healthcare Technology Laboratory, Duke University, Hudson 136 #90281, Durham, NC 27708, USARobert Malkin, Developing World Healthcare Technology Laboratory, Duke University, Hudson 136 #90281, Durham, NC 27708, USA Journal Medica... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4852631 Thu, 19 May 2011 16:36:28 +0100 4852631 http://www.medworm.com/index.php?rid=4852632&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Ff2273pkw1351x460%2F Abstract  In the PREVENIR-5 study, artificial neural networks (NN) were applied to a large sample of patients with recent first acute coronary syndrome (ACS) to identify determinants of persistence of evidence-based cardiovascular medications (EBCM: antithrombotic + beta-blocker + statin + angiotensin converting enzyme inhibitor-ACEI and/or angiotensin-II receptor blocker-ARB). From October 2006 to April 2007, 1,811 general practitioners recruited 4,850 patients with a mean time of ACS occurrence of 24 months. Patient profile for EBCM persistence was determined using automatic rule generation from NN. The prediction accuracy of NN was compared with that of logistic regression (LR) using Area Under Receiver-Operating Characteristics-AUR... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4852632 Thu, 19 May 2011 16:36:27 +0100 4852632 http://www.medworm.com/index.php?rid=4840965&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2F9748147u93222gr5%2F Abstract  In this article, a critical analysis is performed on differences in citation frequency of basic and clinical cardiovascular papers. It appears that the latter papers are cited at about 40% higher frequency. The differences between the largest number of citations of the most cited papers are even larger. It is also demonstrated that the groups of clinical and basic cardiovascular papers are also heterogeneous concerning citation frequency. It is concluded that none of the existing citation indicators appreciates these differences. At this moment these indicators should not be used for quality assessment of individual scientists and scientific niches with small numbers of scientists. Content Type Journal ArticlePages 1-9DOI 10.1007/s11517-011-0783-6Authors Tob... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4840965 Fri, 13 May 2011 05:43:32 +0100 4840965 http://www.medworm.com/index.php?rid=4820502&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fq238044uq703000w%2F Abstract  Various nanoparticles have been developed as imaging probes and drug carriers, and their selectivity in binding to target cells determines the efficacy of these functionalized nanoparticles. Since target cells in different arterial segments experience different hemodynamic environments, we study the effects of wall shear rate waveforms on particle binding. We also explore the effects of the kinetic rate constant, which is determined by particle design parameters, on particle binding. A transport and reaction model is used to evaluate nanoparticle binding to the substrate in a laminar flow chamber. Flow and particle concentration fields are solved by using a computational fluid dynamics. The particle binding rate increases as the mean value of wall shear increases,... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4820502 Tue, 10 May 2011 06:06:44 +0100 4820502 http://www.medworm.com/index.php?rid=4812928&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fvh827q004456567r%2F In this study, we characterize the association of ictal and peri-ictal VENG with cardiac parameters. The electrocorticogram (ECoG), electrocardiogram, and the VENG were recorded in anesthetized rats, which were intravenously infused with either a pentylenetetrazole (PTZ) solution (PTZ-lot, n = 11) or saline (control-lot, n = 6). Control animals were subsequently vagotomized and also infused with a PTZ solution (n = 5, V-PTZ-lot). Cardiac and VENG parameters were assessed during different ECoG stages of ictal activity. None of the parameters changed in the control-lot. PTZ infusion induced seizures in all rats. Cardiac-related VENG showed distinctive firing patterns for the left and right vagus nerves. Significant ictal and post-ictal changes were seen in b... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4812928 Thu, 05 May 2011 05:43:08 +0100 4812928 http://www.medworm.com/index.php?rid=4780161&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fj7828h3612kl8586%2F Abstract  To describe the spatial and temporal profiles of connectivity networks and sources preceding generalized spike-and-wave discharges (SWDs) in human absence epilepsy. Nonlinear associations of MEG signals and cluster indices obtained within the framework of graph theory were determined, while source localization in the frequency domain was performed in the low frequency bands with dynamic imaging of coherent sources. The results were projected on a three-dimensional surface rendering of the brain using a semi-realistic head model and MRI images obtained for each of the five patients studied. An increase in clustering and a decrease in path length preceding SWD onset and a rhythmic pattern of increasing and decreasing connectivity were seen during SWDs. Beamforming s... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4780161 Sat, 30 Apr 2011 05:52:07 +0100 4780161 http://www.medworm.com/index.php?rid=4780162&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fd3604m37x64g6212%2F Abstract  To understand the theoretical effects of pulse width (PW) programming in spinal cord stimulation (SCS), we implemented a mathematical model of electrical fields and neural activation in SCS to gain insight into the effects of PW programming. The computational model was composed of a finite element model for structure and electrical properties, coupled with a nonlinear double-cable axon model to predict nerve excitation for different myelinated fiber sizes. Mathematical modeling suggested that mediolateral lead position may affect chronaxie and rheobase values, as well as predict greater activation of medial dorsal column fibers with increased PW. These modeling results were validated by a companion clinical study. Thus, variable PW programming in SCS appears to ha... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4780162 Thu, 28 Apr 2011 17:17:06 +0100 4780162 http://www.medworm.com/index.php?rid=4753459&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fp47v512436332676%2F Content Type Journal ArticlePages 1-3DOI 10.1007/s11517-011-0779-2Authors Selma Supek, Department of Physics, Faculty of Science, University of Zagreb, Bijenicka c. 32, 10000 Zagreb, CroatiaRatko Magjarevic, Department of Electronic Systems and Information Processing, Faculty of Electrical Engineering and Computing, University of Zagreb, Unska 3, 10000 Zagreb, Croatia Journal Medical and Biological Engineering and ComputingOnline ISSN 1741-0444Print ISSN 0140-0118 (Source: Medical and Biological Engineering and Computing) Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4753459 Thu, 21 Apr 2011 17:44:33 +0100 4753459 http://www.medworm.com/index.php?rid=4753460&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fr0g37102321r2447%2F Abstract  The carotid intima-media thickness (IMT) is the most used marker for the progression of atherosclerosis and onset of cardiovascular diseases. Computer-aided measurements improve accuracy and precision, but usually require user interaction. In this paper we characterized a new and completely automated technique for carotid segmentation and IMT measurement based on the merits of two previously developed techniques. We used an integrated approach of intelligent image feature extraction and line fitting for automatically locating the carotid artery in the image frame, followed by wall interfaces extraction based on a Gaussian edge operator. We called our system—CARES. We validated CARES on a multi-institutional database of 300 carotid ultrasound images. The IMT meas... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4753460 Thu, 21 Apr 2011 06:13:50 +0100 4753460 http://www.medworm.com/index.php?rid=4744746&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2F24l45g68lu0k1245%2F This article represents a novel algorithm for achieving reliable detection and extraction of costal cartilage structures, which can be used for the analysis of motion artifacts, with possible shape variations of the structure caused by uptake of contrast agent, as well as a potential for the registration of breast. The algorithm represented in this article is to extract volume features from post-contrast MR images at three different time slices for the analysis of motion artifacts, and we validate the current algorithm according to the anatomic structure. This utilizes the level-set method [18] for the size selection of the region of interest. The variable shape of contours acquired from a level-set-based segment image actually determines the feature region of interest, which is used ... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4744746 Tue, 19 Apr 2011 07:25:04 +0100 4744746 http://www.medworm.com/index.php?rid=4744748&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2F04p68384h5211511%2F Abstract  Cardiovascular diseases are the leading cause of mortality, morbidity, hospitalization and impaired quality of life. In most, if not all, pathologic cardiac ischemia ensues triggering a succession of events leading to massive death of cardiomyocytes, fibroblast and extracellular matrix accumulation, cardiomyocyte hypertrophy which culminates in heart failure and eventually death. Though current pharmacological treatment is able to delay the succession of events and as a consequence the development of heart failure, the only currently available and effective treatment of end-stage heart failure is heart transplantation. However, donor heart availability and immunorejection upon transplantation seriously limit the applicability. Cardiac regeneration could provide a ... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4744748 Sat, 16 Apr 2011 05:54:40 +0100 4744748 http://www.medworm.com/index.php?rid=4744747&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2F8137kp89650r52lj%2F Abstract  A method to reduce noise for time-domain diffuse optical tomography (DOT) is proposed. Poisson noise which contaminates time-resolved photon counting data is reduced by use of maximum a posteriori estimation. The noise-free data are modeled as a Markov random process, and the measured time-resolved data are assumed as Poisson distributed random variables. The posterior probability of the occurrence of the noise-free data is formulated. By maximizing the probability, the noise-free data are estimated, and the Poisson noise is reduced as a result. The performances of the Poisson noise reduction are demonstrated in some experiments of the image reconstruction of time-domain DOT. In simulations, the proposed method reduces the relative error between the noise-free and... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4744747 Sat, 16 Apr 2011 05:54:40 +0100 4744747 http://www.medworm.com/index.php?rid=4723486&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fr2264t4578m61w1r%2F The objective of this study was to investigate the relationship between cutaneous vasodilatory function and nonlinear complexity of blood flow oscillations (BFO) in older people. A non-painful fast local heating protocol was applied to the sacral skin in 20 older subjects with various vasodilatory functions. Laser Doppler flowmetry was used to measure skin blood oscillations. The complexity of the characteristic frequencies (i.e., metabolic (0.0095–0.02 Hz), neurogenic (0.02–0.05 Hz), myogenic (0.05–0.15 Hz), respiratory (0.15–0.4 Hz), and cardiac (0.4–2 Hz)) of BFO was quantified using the multifractal detrended fluctuation analysis. Compared with the 65–75 years group, the complexity of metabolic BFO in the 75–85 years group was signi... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4723486 Wed, 13 Apr 2011 14:24:18 +0100 4723486 http://www.medworm.com/index.php?rid=4723487&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2F92261pp751952427%2F In this study, we tested this hypothesis by means of a coronary artery occlusion protocol. In six Yorkshire × Landrace swine, we simultaneously occluded the left anterior descending (LAD) and left circumflex (LCx) artery for 5 s followed by a 20-s reperfusion period and repeated this sequence at least two more times. A similar procedure was used to occlude only the right coronary artery (RCA) and finally all three main coronary arteries simultaneously. None of the occlusion protocols caused a decrease in the arterial pressure perturbation in the aorta during occlusion (P > 0.20) nor an increase during reactive hyperemia (P > 0.22), despite a higher deceleration of coronary blood volume flow (P = 0.03) or increased coronary conductanc... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4723487 Wed, 13 Apr 2011 14:24:17 +0100 4723487 http://www.medworm.com/index.php?rid=4723488&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fp2561v374437g774%2F Abstract  Sleep medicine is a growing field with multidisciplinary origins in physiological monitoring techniques, on which it still largely depends. Collaborations between engineers and sleep specialists offer substantial opportunities to improve on current approaches to diagnosis and assessment of patients with sleep problems. Such collaborations could also prove key to improved fundamental understanding of the pathophysiology that underlies sleep disorders and their adverse impact on the brain, cardiovascular system, and optimal health. Content Type Journal ArticlePages 1-3DOI 10.1007/s11517-011-0777-4Authors Ronald D. Chervin, Department of Neurology and Sleep Disorders Center, University of Michigan, C728 Med Inn Bldg 1500 E. Medical Center Dr, Ann Arbor, MI 48109... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4723488 Wed, 13 Apr 2011 14:24:11 +0100 4723488 http://www.medworm.com/index.php?rid=4723489&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fww304n684421301n%2F Abstract  Recordings of brain electrophysiological activity provide the most direct reflect of neural function. Information contained in these signals varies as a function of the spatial scale at which recordings are done: from single cell recording to large scale macroscopic fields, e.g., scalp EEG. Microscopic and macroscopic measurements and models in Neuroscience are often in conflict. Solving this conflict might require the developments of a sort of bio-statistical physics, a framework for relating the microscopic properties of individual cells to the macroscopic or bulk properties of neural circuits. Such a framework can only emerge in Neuroscience from the systematic analysis and modeling of the diverse recording scales from simultaneous measurements. In this article... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4723489 Tue, 12 Apr 2011 06:54:35 +0100 4723489 http://www.medworm.com/index.php?rid=4709036&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fe68805w120012595%2F Abstract  The stereotactic procedure in neurosurgery is a minimally invasive technique used to treat intracranial lesions. The fiducial markers of a frame-based stereotactic procedure are important for defining the stereotactic coordinate system and in locating the target. These markers are often defective in stereotactic images owing to the presence of air bubbles in the imaging indicator. We have assessed the effect of these defects on the registration of an image and on the localization of a target. The virtual phantom method was employed to simulate various types of defect. The virtual images were registered using the Leksell GammaPlan® (LGP) radiosurgery planning system, and the image definition and the target localization errors were assessed. As a result, the effect ... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4709036 Sat, 09 Apr 2011 15:48:52 +0100 4709036 http://www.medworm.com/index.php?rid=4696483&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fk4h05373006j9007%2F This article presents a methodology to align plantar pressure image sequences simultaneously in time and space. The spatial position and orientation of a foot in a sequence are changed to match the foot represented in a second sequence. Simultaneously with the spatial alignment, the temporal scale of the first sequence is transformed with the aim of synchronizing the two input footsteps. Consequently, the spatial correspondence of the foot regions along the sequences as well as the temporal synchronizing is automatically attained, making the study easier and more straightforward. In terms of spatial alignment, the methodology can use one of four possible geometric transformation models: rigid, similarity, affine, or projective. In the temporal alignment, a polynomial transformation u... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4696483 Thu, 07 Apr 2011 17:10:54 +0100 4696483 http://www.medworm.com/index.php?rid=4696482&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fu2u4663051215x3j%2F Abstract  While the relationship between sensory stimulation and tasks and the size of the cortical activations is generally unknown, the visual modality offers a unique possibility of an experimental manipulation of stimulus size-related increases of the spatial extent of cortical activation even during the earliest activity in the retinotopically organized primary visual cortex. We used magnetoecephalography (MEG), visual stimuli of increasing size, and numerical simulations on realistic cortical surfaces to explore the effects of increasing spatial extent of the activated cortical sources on the neuromagnetic fields, location estimation biases, and source resolution. Source localization was performed assuming multiple dipoles in a sphere model using an efficient, automat... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4696482 Thu, 07 Apr 2011 17:10:54 +0100 4696482 http://www.medworm.com/index.php?rid=4696484&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2F336j2v2m4v65h632%2F Abstract  In this article, we aimed to reduce the effects of geometric errors and measurement noise on the inverse problem of Electrocardiography (ECG) solutions. We used the Kalman filter to solve the inverse problem in terms of epicardial potential distributions. The geometric errors were introduced into the problem via wrong determination of the size and location of the heart in simulations. An error model, which is called the enhanced error model (EEM), was modified to be used in inverse problem of ECG to compensate for the geometric errors. In this model, the geometric errors are modeled as additive Gaussian noise and their noise variance is added to the measurement noise variance. The Kalman filter method includes a process noise component, whose variance should also ... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4696484 Wed, 06 Apr 2011 16:25:00 +0100 4696484 http://www.medworm.com/index.php?rid=4683935&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fq58k262823112553%2F This study addresses application of Higuchi’s fractal dimension (FD) as a measure to evaluate the effect of external periodic stressor on electrical oscillations in the brain. Modulated microwave radiation was applied as a weak periodic stressor with strongly inhomogeneous distribution inside the brain. Experiments were performed on a group of 14 volunteers. Ten cycles (1 min on, 1 min off) of 450-MHz microwave radiation modulated at 40 Hz were applied. Higuchi’s FD was calculated in eight symmetric electroencephalographic (EEG) channels located in frontal, temporal, parietal, and occipital areas. FD values averaged over a group detected a small (1–2%) but statistically significant increase with exposure in all EEG channels. FD increased for 12, decreased for one... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4683935 Tue, 05 Apr 2011 10:00:32 +0100 4683935 http://www.medworm.com/index.php?rid=4669972&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2F68l006m6x2223571%2F Abstract  Cardiac resynchronization therapy (CRT) with biventricular pacing (BV) is an established therapy for heart failure (HF) patients with inter- and intraventricular conduction delay. The aim of this pilot study was to test the feasibility of both transesophageal measurement of left ventricular (LV) electrical delay and transesophageal LV pacing prior to implantation, to better select patients for CRT. Esophageal TO8 Osypka catheter was perorally applied in 30 HF patients in position of maximum LV deflection to measure LV electrical delay and to study arterial pulse pressure (PP) during transesophageal bipolar LV pacing. There were 15 responders with a PP increase of a mean 65 ± 24 mmHg to 79 ± 27 mmHg (P < 0.001) and a mean... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4669972 Wed, 30 Mar 2011 05:56:22 +0100 4669972 http://www.medworm.com/index.php?rid=4663727&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Ff72j2r54p6437211%2F Abstract  Electrical impedance tomography (EIT) is a recently developed medical imaging method which has the potential to produce images of fast neuronal depolarization in the brain. Previous modelling suggested that applied current needed to be below 100 Hz but the signal-to-noise ratio (SNR) recorded with scalp electrodes during evoked responses was too low to permit imaging. A novel method in which contemporaneous evoked potentials are subtracted is presented with current applied at 225 Hz to cerebral cortex during evoked activity; although the signal is smaller than at DC by about 10×, the principal noise from the EEG is reduced by about 1000×, resulting in an improved SNR. It was validated with recording of compound action potentials in crab walking leg ner... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4663727 Tue, 29 Mar 2011 17:31:25 +0100 4663727 http://www.medworm.com/index.php?rid=4663726&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fyk26081427675j54%2F Abstract  In the current issue, Chen and co-authors present a mathematical model to simulate shear stress-dependent nitric oxide (NO) transport in a small reconstructed microvascular network. Here their results are discussed in the context of NO-dependent blood flow control. Furthermore, other NO-dependent blood flow control mechanisms are briefly reviewed. Content Type Journal ArticlePages 1-3DOI 10.1007/s11517-011-0762-yAuthors Annemiek J. M. Cornelissen, Laboratoire Matière et Systèmes Complexes (MSC), UMR 7057 CNRS & Université Paris Diderot, Bât. Condorcet, 10, rue Alice Domon et Léonie Duquet, 75205 Paris cedex 13, France Journal Medical and Biological Engineering and ComputingOnline ISSN 1741-0444Print ISSN 0140-0118 (Source: Medical and Biological Eng... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4663726 Tue, 29 Mar 2011 17:31:25 +0100 4663726 http://www.medworm.com/index.php?rid=4663729&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fe1p05n0k81t28475%2F Abstract  We investigated the influence of nicotine exposure and prefrontal cortex (PFC) transections on ventral tegmental areas (VTA) dopamine (DA) neurons’ firing activities using a time–frequency method based on the continuous wavelet transform (CWT). Extracellular single-unit neural activity was recorded from DA neurons in the VTA area of rats. One group had their PFC inputs to the VTA intact, while the other group had the inputs to VTA bilaterally transected immediate caudal to the PFC. We hypothesized that the systemic nicotine exposure will significantly change the energy distribution in the recorded neural activity. Additionally, we investigated whether the loss of inputs to the VTA caused by the PFC transection resulted in the cancellation of the nicotine’ ef... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4663729 Tue, 29 Mar 2011 17:31:24 +0100 4663729 http://www.medworm.com/index.php?rid=4663728&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fn129448376t8x936%2F Abstract  Based on glucose kinetics minimal model (GKMM) interpretation of frequently sampled intravenous glucose tolerance test (FSIGTT), the aim was to broaden the characterization of insulin-mediated glucose disposal in hypertension by aid of a dynamic insulin sensitivity index, S\textI\textD , and the related efficiency, h = S\textI\textD /S\textI , of the metabolic system to convert the maximal individual response capacity, measured by S I, into an effective insulin control on glucose. The C-peptide minimal model (CPMM) was used to interpret the role of β-cell function. Plasma glucose, insulin, and C-peptide concentrations were measured, during a 5-h FSIGTT, in eighteen normoglycemic individuals: ten hypertensive patients (H-group) and eight ... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4663728 Tue, 29 Mar 2011 17:31:24 +0100 4663728 http://www.medworm.com/index.php?rid=4663730&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2F86v51141t4jkv8h6%2F In this study, an algorithm was developed for the offline breath-to-breath analysis of the nocturnal respiratory recordings. For that purpose, respiratory signals (nasal airway pressure, thoracic and abdominal movements) were divided into half waves using period amplitude analysis. Individual breaths were characterized by the parameters of the half waves (duration, amplitude, and slope). These values can be used to discriminate between normal and abnormal breaths. This algorithm was applied to six polysomnographic recordings to distinguish abnormal breathing events (apneas and hypopneas). The algorithm was robust for the identification of breaths (sensitivity = 96.8%, positive prediction value (PPV) = 99.5%). The detection of apneas and hypopneas was compared to ... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4663730 Tue, 29 Mar 2011 07:03:52 +0100 4663730 http://www.medworm.com/index.php?rid=4642348&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fn531691654813851%2F Abstract  In this article, a new spatial filtering approach, called discriminant common spatial patterns (dCSP), is proposed for single-trial EEG classification. Unlike the conventional common spatial patterns (CSP) that is substantially a subspace decomposition technique, dCSP is intently designed for discriminant purpose. The basic idea of dCSP is to construct a Fisher-like criterion that extracts both between-class and within-class discriminant information. The classical CSP only considers separating class means, i.e., between-class scatter, as well as possible. In contrast, dCSP aims to maximize between-class scatter and meanwhile minimize within-class scatter. Computationally, dCSP is formulated as a generalized eigenvalue problem. Experiments on real EEG classification... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4642348 Fri, 25 Mar 2011 06:00:12 +0100 4642348 http://www.medworm.com/index.php?rid=4642349&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2F62101817642t7r17%2F Content Type Journal ArticlePages 1-2DOI 10.1007/s11517-011-0765-8Authors Xuewen Chen, School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA 19104, USADonald G. Buerk, School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA 19104, USAKenneth A. Barbee, School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA 19104, USAPatrick Kirby, School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA 19104, USADov Jaron, School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA 19104, USA Journal Medical and Biological Engineering and ComputingOnline ISSN 1741-0444Print ISSN 0140-0118 (... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4642349 Fri, 25 Mar 2011 06:00:11 +0100 4642349 http://www.medworm.com/index.php?rid=4642350&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2F32uv7441t8327382%2F Abstract  We developed a mathematical model to simulate shear stress-dependent nitric oxide (NO) production and transport in a 3D microcirculatory network based on published data. The model consists of a 100 μm × 500 μm × 75 μm rectangular volume of tissue containing two arteriole-branching trees, and nine capillaries surrounding the vessels. Computed distributions for NO in blood, vascular walls, and surrounding tissue were affected by hematocrit (Hct) and wall shear stress (WSS) in the network. The model demonstrates that variations in the red blood cell (RBC) distribution and WSS in a branching network can have differential effects on computed NO concentrations due to NO consumption by RBCs and WSS-dependent changes in NO production... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4642350 Wed, 23 Mar 2011 16:58:35 +0100 4642350 http://www.medworm.com/index.php?rid=4642351&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2F22k76k201335w4h1%2F Abstract  An experimental study was conducted to classify the influence of trabecular architecture and cortical shell thickness on the mechanical properties using a bone surrogate. Thirty-six rectangular prisms and 18 vertebral-shaped specimens were fabricated with fused deposition modelling (FDM) as a bone surrogate with controlled structural characteristics (cortical wall thickness, strut spacing, strut angle and strut orientation). The apparent density of the FDM specimens was evaluated using quantitative computed tomography (QCT) imaging and related to the apparent elastic modulus measured with compression testing. The effects of the structural parameters on the apparent elastic modulus were analysed using analysis of variance (ANOVA). The results obtained corroborate t... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4642351 Wed, 23 Mar 2011 16:58:32 +0100 4642351 http://www.medworm.com/index.php?rid=4610642&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2F1707576252144264%2F Abstract  Applied low-intensity direct current (DC) stimulates and directs axonal growth in models of spinal cord injury (SCI) and may have therapeutic value in humans. Using higher electric strengths will probably increase the beneficial effects, but this faces the risk of tissue damage by electricity or toxic reactions at the electrode–tissue interface. To inform the optimisation of DC-based therapeutics, we developed a finite element model (FEM) of the human cervical spine and calculated the electric fields (EFs) and current densities produced by electrodes of different size, geometry and location. The presence of SCI was also considered. Three disc electrodes placed outside the spine produced low-intensity, uneven EFs, whereas the EFs generated by the same electrodes ... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4610642 Tue, 15 Mar 2011 17:31:33 +0100 4610642 http://www.medworm.com/index.php?rid=4610643&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fq07xj6j1n24q1k23%2F Abstract  This work attempts to recognize the Arabic vowels based on facial electromyograph (EMG) signals, to be used for people with speech impairment and for human computer interface. Vowels were selected since they are the most difficult letters to recognize by people in Arabic language. Twenty subjects (7 females and 13 males) were asked to pronounce three Arabic vowels continuously in a random order. Facial EMG signals were recorded over three channels from the three main facial muscles that are responsible for speech. The EMG signals are then pre-processed to eliminate noise and interference signals. Segmentation procedure was implemented to extract the time event that corresponds to each vowel based on a moving standard deviation window. The accuracy of the segmentat... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4610643 Tue, 15 Mar 2011 17:31:32 +0100 4610643 http://www.medworm.com/index.php?rid=4610644&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fw17w284714422u82%2F Abstract  There is a strong clinical demand for devices allowing continuous non-invasive monitoring of central blood pressure (BP). In the state of the art a new family of techniques providing BP surrogates based on the measurement of the so-called pulse wave velocity (PWV) has been proposed, eliminating the need for inflation cuffs. PWV is defined as the velocity at which pressure pulses propagate along the arterial wall. However, no technique to assess PWV within central arteries in a fully unsupervised manner has been proposed so far. In this pilot study, we provide first experimental evidence that electrical impedance tomography (EIT) is capable of measuring pressure pulses directly within the descending aorta. To obtain a wide range of BP values, we administrated norad... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4610644 Tue, 15 Mar 2011 05:47:14 +0100 4610644 http://www.medworm.com/index.php?rid=4580842&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2F6816n28827242j01%2F Abstract  A mechanomyogram (MMG) from single motor units of the anconeus muscle in voluntary isometric contraction was recorded from seven subjects using a spike-triggered averaging technique. The MMG system, in which the input was an ideal impulse and the output was the MMG detected with an acceleration sensor, was identified as the fifth-order model by the subspace-based state-space model identification method. The transfer function of the MMG system was factorized to the second- and the first-order models. The second-order model was compared to the standard form of the second-order model, and its resonance frequency was calculated. The resonance frequencies of the second-order models were 166 ± 61 and 93 ± 27 Hz, which were within the range of t... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4580842 Fri, 11 Mar 2011 06:52:28 +0100 4580842 http://www.medworm.com/index.php?rid=4580841&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fnv64063g182wnjn5%2F Abstract  Spinal cord injury patients are under daily risk for developing deep tissue injury which is a severe pressure ulcer that initiates in soft tissues at the bones’ proximity. We aimed to formulate a patient-specific biomechanical model that can continuously monitor internal tissue stresses in real time. We adopted a formulation solving an axisymmetric contact problem of a finite-thickness, elastic layer (soft tissue), and a rigid spherical indentor (ischial tuberosity). We utilized finite element analyses to expand the formulation for large deformations. Sensitivity analyses showed that the soft tissue mechanical properties are the most influential factors in this modeling. We then used synthetic surface pressure data and actual surface pressures recorded under the... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4580841 Fri, 11 Mar 2011 06:52:28 +0100 4580841 http://www.medworm.com/index.php?rid=4580843&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fdr39p53103mr23j6%2F Abstract  A Brain–Computer Interface (BCI) is a device that transforms brain signals, which are intentionally modulated by a user, into control commands. BCIs based on motor imagery (MI) and steady-state visual evoked potentials (SSVEP) can partially restore motor control in spinal cord injured patients. To determine whether these BCIs can be combined for grasp and elbow function control independently, we investigated a control method where the beta rebound after brisk feet MI is used to control the grasp function, and a two-class SSVEP-BCI the elbow function of a 2 degrees-of-freedom artificial upper limb. Subjective preferences for the BCI control were assessed with a questionnaire. The results of the initial evaluation of the system suggests that this is feasible. ... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4580843 Fri, 11 Mar 2011 06:52:26 +0100 4580843 http://www.medworm.com/index.php?rid=4521943&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Ffm68504032l32tp3%2F Abstract  Results of self-consistent analyses of cells show the possibility of temperature increases at membranes in response to a single nanosecond, high-voltage pulse, at least over small sections of the membrane. Molecular Dynamics simulations indicate that such a temperature increase could facilitate poration, which is one example of a bio-process at the plasma membrane. Our study thus suggests that the use of repetitive high-intensity voltage pulses could open up possibilities for a host of synergistic bio-responses involving both thermal and electrically driven phenomena. Content Type Journal ArticlePages 1-6DOI 10.1007/s11517-011-0745-zAuthors J. Song, Department of Electrical and Computer Engineering and Frank Reidy Center for Bio-Electrics, Old Dominion Univer... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4521943 Tue, 22 Feb 2011 06:58:16 +0100 4521943 http://www.medworm.com/index.php?rid=4521942&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fp76g00223455q552%2F This study examines cardiovascular recovery from mental stress. Investigating the absence or presence of carryover effect, the effect of the final reactivity observed at the end of stressful task on the successive recovery, was the major objective. A recently advocated recovery measure related to the area under the curve, mean recovery rate (MRR), was investigated, comparing with the two relatives of this type, total carryover (TCO) and literally area under the curve (AUC). At the onset, a detailed theoretical formulation of each measure was carried out, starting from its original definition. It was predicted that MRR, but not TCO or AUC, could be free from the carryover effect. Next, 88 male students underwent a 5-min mental arithmetic during which blood pressure and heart rate were... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4521942 Tue, 22 Feb 2011 06:58:16 +0100 4521942 http://www.medworm.com/index.php?rid=4521944&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fnj21752622722456%2F In this study, we examined the association between fingertip PPG waveform variability (PPGV) and systemic vascular resistance (SVR) obtained from thermodilution cardiac output (CO) and intra-arterial pressure measurements in 48 post cardiac surgery intensive care unit patients. Among the hemodynamic measurements, both CO (P < 0.05) and SVR (P < 0.0001) had statistically significant relationships with the normalized low frequency power (LFnu) of PPGV. The LFnu of baseline PPGV had moderate but significant positive correlation with SVR (r = 0.54, P < 0.0001), and a value below 52.5 nu was able to identify SVR < 900 dyn s cm−5 with sensitivity of 59% and specificity of 95%. The results have provided quantit... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4521944 Tue, 22 Feb 2011 06:58:14 +0100 4521944 http://www.medworm.com/index.php?rid=4512214&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fr548871277815053%2F Abstract  Short and long-term alterations of ballistocardiographic parameters (BCG) were studied in a sitting position using Electromechanical Film (EMFi) sensors. Several physiological parameters were recorded from 48 men of middle age in consecutive recordings and after a 2-week interval. The duration and amplitudes of the signal components were studied. The repeatability index R, the Pearson correlation, and Bland–Altman (BA) repeatability methods were used to determine how repeatable the studied signals are. In consecutive and during 2 week recordings, the Pearson correlation rates for BCG systolic component values (from 0.88/0.83 (T RJ) to 0.97/0.78 (A IJ), PWV values for the left 0.97/0.67 and right ankle 0.98/0.76) were detected indicating excellent repeatabil... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4512214 Sat, 19 Feb 2011 06:59:11 +0100 4512214 http://www.medworm.com/index.php?rid=4501415&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2F5q80189878773687%2F We present two techniques utilizing independent component analysis (ICA) to remove large muscle artifacts from transcranial magnetic stimulation (TMS)-evoked EEG signals. The first one is a novel semi-automatic technique, called enhanced deflation method (EDM). EDM is a modification of the deflation mode of the FastICA algorithm; with an enhanced independent component search, EDM is an effective tool for removing the large, spiky muscle artifacts. The second technique, called manual method (MaM) makes use of the symmetric mode of FastICA and the artifactual components are visually selected by the user. In order to evaluate the success of the artifact removal methods, four different quality parameters, based on curve comparison and frequency analysis, were studied. The dorsal premotor... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4501415 Fri, 18 Feb 2011 06:46:15 +0100 4501415 http://www.medworm.com/index.php?rid=4501416&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2F657w7p2u24686424%2F Abstract  The aim of this research is to analyze the changes in the EEG frontal activity during the observation of commercial videoclips. In particular, we aimed to investigate the existence of EEG frontal asymmetries in the distribution of the signals’ power spectra related to experienced pleasantness of the video, as explicitly rated by the eleven experimental subjects investigated. In the analyzed population, maps of Power spectral density (PSD) showed an asymmetrical increase of theta and alpha activity related to the observation of pleasant (unpleasant) advertisements in the left (right) hemisphere. A correlation analysis revealed that the increase of PSD at left frontal sites is negatively correlated with the degree of pleasantness perceived. Conversely, the de-sync... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4501416 Thu, 17 Feb 2011 06:53:57 +0100 4501416 http://www.medworm.com/index.php?rid=4470209&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fggn681u350667v60%2F In this study, we investigated experimentally the possibility of modulating protein activity by low intensity microwaves by measuring alternations of l-Lactate Dehydrogenase enzyme (LDH) activity. The LDH enzyme solutions were irradiated by microwaves of the selected frequencies and powers using the Transverse Electro-Magnetic (TEM) cell. The kinetics of the irradiated LDH was measured by continuous monitoring of nicotine adenine dinucleotide, reduced (NADH) absorbance at 340 nm. A comparative analysis of changes in the activity of the irradiated LDH enzyme versus the non-radiated enzyme was performed for the selected frequencies and powers. It was found that LDH activity can be selectively increased only by irradiation at the particular frequencies of 500 MHz [electric fiel... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4470209 Thu, 10 Feb 2011 06:55:25 +0100 4470209 http://www.medworm.com/index.php?rid=4470210&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fy568170254687733%2F Abstract  A validated lattice-Boltzmann code has been developed based on the Bhatnagar–Gross–Krook formulation to simulate and analyze transient laminar two-dimensional airflow in alveoli and bifurcating alveolated ducts with moving walls, representative of the human respiratory zone. A physically more realistic pressure boundary condition has been implemented, considering a physiological Reynolds number range, i.e., 0 < Re < 11, which covers the inhalation scenarios from resting mode to moderate exercise. Axial velocity contours, vortex propagation, and streamlines as well as mid-plane pressure variations in different alveolar geometries and shapes are illustrated and discussed. The results show that the influence of the geometric structure on ... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4470210 Thu, 10 Feb 2011 06:55:24 +0100 4470210 http://www.medworm.com/index.php?rid=4464342&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2F816385m53k50w3tk%2F In this study, we used simulated and face-evoked empirical MEG data from an oddball study to investigate the feasibility of accurate, efficient, and reliable spatio-temporal tracking of cortical pathways over prolonged time intervals. We applied a data-driven, semiautomated approach to spatio-temporal source localization with no prior assumptions on active cortical regions to explore non-invasively face-processing dynamics and their modulation by task. Simulations demonstrated that the use of multi-start downhill simplex and data-driven selections of time intervals submitted to the Calibrated Start Spatio-Temporal (CSST) algorithm resulted in improved accuracy of the source localization and the estimation of the onset of their activity. Locations and dynamics of the identified source... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4464342 Wed, 09 Feb 2011 17:26:46 +0100 4464342 http://www.medworm.com/index.php?rid=4441901&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fk887xm248k10405j%2F Abstract  The methods applied for estimation of functional connectivity from multichannel data are described with special emphasis on the estimators of directedness such as directed transfer function (DTF) and partial directed coherence. These estimators based on multivariate autoregressive model are free of pitfalls connected with application of bivariate measures. The examples of applications illustrating the performance of the methods are given. Time-varying estimators of directedness: short-time DTF and adaptive methods are presented. Content Type Journal ArticlePages 1-9DOI 10.1007/s11517-011-0739-xAuthors Katarzyna J. Blinowska, Department of Biomedical Physics, University of Warsaw, Hoza 69, Warsaw, Poland Journal Medical and Biological Engineering and Co... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4441901 Fri, 04 Feb 2011 17:49:00 +0100 4441901 http://www.medworm.com/index.php?rid=4441902&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fc10105554523q755%2F In conclusion, the model developed presents improvements over previous models and could be used to better understand and optimize brace treatment. Content Type Journal ArticlePages 1-11DOI 10.1007/s11517-011-0737-zAuthors Julien Clin, Department of Mechanical Engineering, École Polytechnique de Montréal, P.O. Box 6079, Station Centre-ville, Montreal, QC H3C 3A7, CanadaCarl-Éric Aubin, Department of Mechanical Engineering, École Polytechnique de Montréal, P.O. Box 6079, Station Centre-ville, Montreal, QC H3C 3A7, CanadaStefan Parent, Sainte-Justine University Hospital Center, 3175 Côte-Ste-Catherine Rd., Montreal, QC H3T 1C5, CanadaHubert Labelle, Sainte-Justine University Hospital Center, 3175 Côte-Ste-Catherine Rd., Montreal, QC H3T 1C5, Canada Journal Medical and Bi... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4441902 Thu, 03 Feb 2011 07:06:48 +0100 4441902 http://www.medworm.com/index.php?rid=4441903&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2F0618112xk810tt4n%2F Abstract  To improve the biological activity of titanium, by using of glow discharge plasma (GDP), albumin-grafted titanium disk have been implemented and carefully studied. Titanium disks were pre-treated with GDP in an environment filled with argon and allylamine gas. Glutaraldehyde was used as a cross-linking agent for albumin grafting. Then, the surface of the albumin-grafted titanium was examined using scanning electron microscopy and X-ray photoelectron spectroscopy. In addition, the static water contact angles of the albumin-grafted titanium disks were measured using goniometry. To observe the effects of albumin adsorption on cell behavior, MG-63 osteoblast-like cells were cultured on the surface-modified titanium disks. Blood coagulation resistance of the modified t... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4441903 Tue, 01 Feb 2011 15:51:19 +0100 4441903 http://www.medworm.com/index.php?rid=4441904&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Ff876765k36mx4455%2F In this study, the authors present a computational model that uses support vector machines to predict human poly(A) sites. The results show that this predictive model has a comparable performance to the current prediction tool. In addition, it was identified common structural patterns associated with polyadenylation using several motif finding programs and this provides new insight into the role of RNA secondary structure plays in polyadenylation. Content Type Journal ArticlePages 1-10DOI 10.1007/s11517-011-0732-4Authors Tzu-Hao Chang, Institute of Bioinformatics and Systems Biology, National Chiao-Tung University, Hsin-Chu, TaiwanLi-Ching Wu, Institute of Systems Biology and Bioinformatics, National Central University, Jhongli, TaiwanYu-Ting Chen, Department of Computer Science ... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4441904 Tue, 01 Feb 2011 15:51:17 +0100 4441904 http://www.medworm.com/index.php?rid=4441905&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fn54jn33x13240n22%2F Abstract  Aortic stiffness measurement is well recognized as an independent predictor of cardiovascular mortality and morbidity. Recently, a simple method has been proposed for the evaluation of the local aortic stiffness (AoStiff) using a non-invasive bioelectrical impedance (BI) technique. This approach relies on a novel interpretation of the arterial stiffness where AoStiff is computed from the measurement of two new BI variables: (1) the local aortic flow resistance (AoRes) exerted by the drag forces onto the flow; (2) the local aortic wall distensibility (AoDist). Herein, we propose to detail and compare these three indices with the reference pulse wave velocity (PWV) measurement and the direct assessment of the aortic drag forces (DF) and distensibility (DS) obtained ... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4441905 Tue, 01 Feb 2011 15:51:16 +0100 4441905 http://www.medworm.com/index.php?rid=4418885&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fx5n0745084032lp8%2F Abstract  Diabetic retinopathy (DR) is a sight threatening complication due to diabetes mellitus that affects the retina. In this article, a computerised DR grading system, which digitally analyses retinal fundus image, is used to measure foveal avascular zone. A v-fold cross-validation method is applied to the FINDeRS database to evaluate the performance of the DR system. It is shown that the system achieved sensitivity of >84%, specificity of >97% and accuracy of >95% for all DR stages. At high values of sensitivity (>95%), specificity (>97%) and accuracy (>98%) obtained for No DR and severe NPDR/PDR stages, the computerised DR grading system is suitable for early detection of DR and for effective treatment of severe cases. Content Type Journal Artic... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4418885 Thu, 27 Jan 2011 01:08:18 +0100 4418885 http://www.medworm.com/index.php?rid=4418886&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2F66rx77230v82656l%2F Abstract  Previous research on spinal motion during walking has been restricted to the level walking condition in a gait lab although staircase walking (i.e., stair ascent and descent) exhibits unique biomechanical characteristics. A major difficulty in spinal motion capture during staircase walking is the in-the-lab limitation of measurement techniques. The purpose of this article is twofold: (i) to present an ambulatory spinal motion measurement system based on inertial and magnetic sensors (IMSs) to overcome this limitation and (ii) to demonstrate its application to 3D spinal motion analysis during staircase walking to fill a gap in the spinal kinematics literature. The proposed system is comprised of three tri-axial IMSs on the pelvis/spine measuring 3D angular motions ... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4418886 Thu, 27 Jan 2011 01:08:17 +0100 4418886 http://www.medworm.com/index.php?rid=4418887&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2F608k702352107360%2F This article describes an ambulatory gait event detection method for long-term monitoring of walking. Aminian et al. [2] have developed an automatic gait event detection algorithm based on shank-attached gyroscope signals. However, this algorithm has a drawback in that it is post-processed. We propose a modified algorithm which detects foot initial and end contact timings using the same concept as in [2], but in quasi real-time. The utilization of the knowledge on gait sequence and peak angular acceleration realizes the quasi real-time detection. Furthermore, to be practical, the algorithm has been developed to ensure the robustness of detection (i.e., without missing the gait events in various speed conditions). Validation of the algorithm using footswitches shows that the algorithm ... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4418887 Wed, 26 Jan 2011 19:50:35 +0100 4418887 http://www.medworm.com/index.php?rid=4355606&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fd622177225775316%2F This study aims at evaluating AS subjects gait alterations. Twenty-four subjects were evaluated: 12 normal and 12 pathologic in stabilized anti-TNF-alpha treatment (mean age 49.42 (10.47), 25.44 (3.19) and mean body mass index 55.75 (3.19), 23.73 (2.7), respectively). Physical examination and gait analysis were performed. A motion capture system synchronized with two force plates was used. Three-dimensional kinematics and kinetics of trunk, pelvis, hip, knee and ankle were determined during gait. A trend towards reduction was found in gait velocity and stride length. Gait analysis results showed statistically significant alterations in the sagittal plane at each joint for AS patients (P < 0.049). Hip and knee joint extension moments showed a statistically significant redu... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4355606 Thu, 13 Jan 2011 07:06:56 +0100 4355606 http://www.medworm.com/index.php?rid=4355607&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fc8552r4k72712528%2F This article discusses the impedance method in the forward calculation in magnetic induction tomography (MIT). Magnetic field and eddy current distributions were obtained numerically for a sphere in the field of a coil and were compared with an analytical model. Additionally, numerical and experimental results for phase sensitivity in MIT were obtained and compared for a cylindrical object in a planar array of sensors. The results showed that the impedance method provides results that agree very well with reality in the frequency range from 100 kHz to 20 MHz and for low conductivity objects (10 S/m or less). This opens the possibility of using this numerical approach in image reconstruction in MIT. Content Type Journal ArticlePages 1-8DOI 10.1007/s11517-011-0733-3A... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4355607 Thu, 13 Jan 2011 07:06:55 +0100 4355607 http://www.medworm.com/index.php?rid=4342939&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fg081n71625g43853%2F Abstract  A novel adaptive and approximate shift-invariant wavelet packet feature extraction scheme for event-related potentials (ERPs) in the electroencephalogram (EEG) is introduced in this paper. In this algorithm, the shift-invariant wavelet packed decomposition is done by integrating a cost function for decimation decision in each sub-band expansion. Additionally, a shape adaptation of the wavelet is implemented to find the best adapted wavelet shape for a given class of ERPs. This scheme is used to analyze the time course of the impact of single-pulse transcranial magnetic stimulation (TMS) to the auditory ERPs. We show that the proposed scheme is able to extract even slightest impacts of TMS, making it a promising tool for the extraction of weak ERPs components, part... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4342939 Tue, 11 Jan 2011 07:33:39 +0100 4342939 http://www.medworm.com/index.php?rid=4326842&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fu808n3916h761730%2F Abstract  The mechanical characterization of cells is important for understanding cellular behavior and physiological functions. We used atomic force microscopy (AFM) to obtain a force–displacement curve and estimate the elastic modulus of hepatocellular carcinoma cells (HEP-G2) utilizing both linear Hertz–Sneddon (HS) and non-linear elastic models. In order to overcome the limitations of HS model, which assumes a linear homogeneous cell body, a cell is modeled as a double-layered body with an outer cytoplasmic layer made mostly of interconnected fibers of cytoskeleton proteins and a nucleus. By disrupting all cytoskeletal protein networks, we estimate the elastic modulus of the core nucleus using FEM for a single ellipsoid. Based on the nucleic modulus and cellular dim... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4326842 Fri, 07 Jan 2011 14:51:27 +0100 4326842 http://www.medworm.com/index.php?rid=4322340&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2F44741p485261277j%2F This study aims to evaluate the potential of transfecting bone morphogenetic protein-7 (BMP-7), a secretory protein, into bone marrow-derived mesenchymal stem cells (BMSCs), in inducing the differentiation of bone marrow stromal cells into chondrocytes in vitro. The phenotypes of the cells were observed by alcian blue staining and H&E staining with an inverted microscope. The glycosaminoglycan (GAG) content of BMSCs transfected with pcDNA3.1-BMP7 or induced by inducing medium was examined after 7, 14, or 21 days of incubation. A standard curve as reference for BMSCs’ GAG content was plotted using galacturonic acid. The content of type II collagen in culture medium was detected by ELISA. Our results demonstrated that BMP7-transfected BMSCs or BMSCs incubated with inducing mediu... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4322340 Wed, 05 Jan 2011 16:52:28 +0100 4322340 http://www.medworm.com/index.php?rid=4322341&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fk1u71265x3430316%2F Abstract  Flow impingement is regarded as a key factor for aneurysm formation and rupture. Wall shear stress (WSS) is often used to evaluate flow impingement even though WSS and impinging force are in two different directions; therefore, this raises an important question of whether using WSS for evaluation of flow impingement size is appropriate. Flow impinging behavior in a patient-specific model of a giant aneurysm (GA) at the internal carotid artery (ICA) was analyzed by computational fluid dynamics simulations. An Impingement Index (IMI) was used to evaluate the timing and size of flow impingement. In theory, the IMI is related to the WSS gradient, which is known to affect vascular biology of endothelial cells. Effect of non-Newtonian fluid, aneurysm size, and heart rat... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4322341 Wed, 05 Jan 2011 16:52:27 +0100 4322341 http://www.medworm.com/index.php?rid=4318135&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fyx5619162u0l7k3p%2F This study proposes a finite element (FE) model of the extracellular potential and stochastic branching fiber model of the afferent fiber excitation thresholds. The FE model described four horizontal layers; stratum corneum, epidermis, dermis, and hypodermal used to estimate the excitation threshold of Aβ-fibers terminating in dermis and Aδ-fibers terminating in epidermis. The perception thresholds of 11 electrodes with diameters ranging from 0.2 to 20 mm were modeled and assessed on the volar forearm of healthy human volunteers by an adaptive two-alternative forced choice algorithm. The model showed that the magnitude of the current density was highest for smaller electrodes and decreased through the skin. The excitation thresholds of the Aδ-fibers were lower than the excita... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4318135 Tue, 04 Jan 2011 17:54:30 +0100 4318135 http://www.medworm.com/index.php?rid=4313774&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fc5739h26192h7762%2F Abstract  The aim of this study was to investigate the discrimination power of standard long-term heart rate variability (HRV) measures for the diagnosis of chronic heart failure (CHF). The authors performed a retrospective analysis on four public Holter databases, analyzing the data of 72 normal subjects and 44 patients suffering from CHF. To assess the discrimination power of HRV measures, an exhaustive search of all possible combinations of HRV measures was adopted and classifiers based on Classification and Regression Tree (CART) method was developed, which is a non-parametric statistical technique. It was found that the best combination of features is: Total spectral power of all NN intervals up to 0.4 Hz (TOTPWR), square root of the mean of the sum of the squares... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4313774 Mon, 03 Jan 2011 18:05:37 +0100 4313774 http://www.medworm.com/index.php?rid=4302056&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2F33g2146630t4u417%2F Abstract  Co-registration of brain SPECT and MR images has been used extensively in clinical applications. The complementary features of two major co-registration methods—surface- and mutual-information-based (MI-based)—motivated us to study a hybrid-based scheme that uses the surface-based method to achieve a quick alignment, followed by the MI-based method for fine tuning. Computer simulations were conducted to evaluate the accuracy and robustness of surface-, MI-, and hybrid-based registration methods by designing different levels of noise and mismatch in the registration experiments. Results demonstrated that the hybrid surface-MI-based scheme outperforms both the surface- and MI-based methods in providing superior accuracy and success rates. Specifically, the trans... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4302056 Wed, 29 Dec 2010 17:13:21 +0100 4302056 http://www.medworm.com/index.php?rid=4288469&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fml557175712775p4%2F Content Type Journal ArticleDOI 10.1007/s11517-010-0723-xAuthors Ruben Coronel, Academic Medical Center, University of Amsterdam, Amsterdam, The NetherlandsJos A. Spaan, Academic Medical Center, Amsterdam, The NetherlandsHerbert F. Voigt, Boston University, Boston, MA USA Journal Medical and Biological Engineering and ComputingOnline ISSN 1741-0444Print ISSN 0140-0118 (Source: Medical and Biological Engineering and Computing) Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4288469 Thu, 23 Dec 2010 18:01:27 +0100 4288469 http://www.medworm.com/index.php?rid=4285073&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2F606882130211677m%2F Abstract  The problem of excess cerebrospinal fluid in the brain (hydrocephalus) is generally managed using a passive pressure or flow regulated mechanical shunt. Despite the success of such devices, they have been plagued with a number of problems. It is desirable to have a shunt valve that responds dynamically to the changing needs of the patient, opening and closing according to a dynamic physiological pattern, rather than simply to the hydrostatic pressure across the valve. Such a valve would by necessity be mechatronic, electronically controlled by software. In this article, different methods for controlling such a mechatronic valve are explored, and the effect of current hydrocephalus management techniques on the intracranial hydrodynamics of acute hydrocephalus patie... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4285073 Mon, 20 Dec 2010 22:53:57 +0100 4285073 http://www.medworm.com/index.php?rid=4265201&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Flr1382j02tw13130%2F Abstract  Sepsis is associated with impairment in autonomic regulatory function. This work investigates the application of heart rate and photoplethysmogram (PPG) waveform variability analysis in differentiating two categories of sepsis, namely systemic inflammatory response syndrome (SIRS) and severe sepsis. Electrocardiogram-derived heart period (RRi) and PPG waveforms, measured from fingertips (Fin-PPG) and earlobes (Ear-PPG), of Emergency Department sepsis patients (n = 28) with different disease severity, were analysed by spectral technique, and were compared to control subjects (n = 10) in supine and 80° head-up tilted positions. Analysis of covariance (ANCOVA) was applied to adjust for the confounding factor of age. Low-frequency (LF, 0.04–0.15&n... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4265201 Tue, 14 Dec 2010 06:41:52 +0100 4265201 http://www.medworm.com/index.php?rid=4248921&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fp705v1875k6t1773%2F Abstract  Surface electromyography (sEMG) is a common technique used in the assessment of local muscle fatigue. As opposed to static contraction situations, sEMG recordings during dynamic contractions are particularly characterised by non-stationary (and non-linear) features. Standard signal processing methods using Fourier and wavelet based procedures demonstrate well known restrictions on time–frequency resolution and the ability to process non-stationary and/or non-linear time-series, thus aggravating the spectral parameters estimation. The Hilbert–Huang transform (HHT), comprising of the empirical mode decomposition (EMD) and Hilbert spectral analysis (HSA), provides a new approach to overcome these issues. The time-dependent median frequency estimate is used as mus... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4248921 Wed, 08 Dec 2010 17:54:13 +0100 4248921 http://www.medworm.com/index.php?rid=4248922&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fx306628337451111%2F Abstract  Ballistocardiography (BCG) is a non-invasive technique used to measure the ejection force of blood into the aorta which can be used to estimate cardiac output and contractility change. In this work, a noise sensor was embedded in a BCG measurement system to detect excessive motion from standing subjects. For nine healthy subjects, the cross-correlation of the motion signal to the BCG noise—estimated using a simultaneously acquired electrocardiogram and statistics of the BCG signal—was found to be 0.94 and 0.87, during periods of standing still and with induced motion artifacts, respectively. In a separate study, where 35 recordings were taken from seven subjects, a threshold-based algorithm was used to flag motion-corrupted segments of the BCG signal using onl... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4248922 Wed, 08 Dec 2010 17:54:11 +0100 4248922 http://www.medworm.com/index.php?rid=4245070&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Ff5414023611t5530%2F This study has aimed to develop a novel pre-diagnostic tool for primary care screening of heart disease based on multivariate short-term heart rate variability (HRV) analyzed by linear (time and frequency domain) and nonlinear methods (compression entropy (CE), detrended fluctuation analysis (DFA), Poincaré plot analysis, symbolic dynamics) applied to 5-min ECG segments. Firstly, we applied HRV analysis to separate healthy subjects (REF) from heart disease patients (PAT). Then to optimize the results, we subdivided both groups according to gender: REF (♂ = 78, ♀ = 53) versus PAT (♂ = 378, ♀ = 115). Finally, we divided REF and PAT into two age subgroups (30–50 years vs. 51-70 years of age) to consider the influence of age on ... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4245070 Tue, 07 Dec 2010 16:45:10 +0100 4245070 http://www.medworm.com/index.php?rid=4230087&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fm5x62x7l7732p12j%2F Abstract  In neurosurgery, cranial incisions during craniotomy can be recovered by cranioplasty—a surgical operation using cranial implants to repair skull defects. However, surgeons often encounter difficulties when grafting prefabricated cranial plates into defective areas, since a perfect match to the cranial incision is difficult to achieve. Previous studies using mirroring technique, surface interpolation, or deformed template had limitations in skull reconstruction to match the patient’s original appearance. For this study, we utilized low-resolution and high-resolution computed tomography images from the patient to repair skull defects, whilst preserving the original shape. Since the accuracy of skull reconstruction was associated with the partial volume effects ... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4230087 Thu, 02 Dec 2010 18:16:28 +0100 4230087 http://www.medworm.com/index.php?rid=4224861&cid=s_33325_169_f&fid=33325&url=http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Fe7513r45125606g8%2F Abstract  How to design a clinical test aimed at identifying in the safest, most precise and quickest way the subject-specific parameters of a detailed model of glucose homeostasis in type 1 diabetes is the topic of this article. Recently, standard techniques of model-based design of experiments (MBDoE) for parameter identification have been proposed to design clinical tests for the identification of the model parameters for a single type 1 diabetic individual. However, standard MBDoE is affected by some limitations. In particular, the existence of a structural mismatch between the responses of the subject and that of the model to be identified, together with initial uncertainty in the model parameters may lead to design clinical tests that are sub-optimal (scarcely informa... Medical and Biological Engineering and Computing journals http://www.medworm.com/rss/comments.php?id=4224861 Tue, 30 Nov 2010 07:06:10 +0100 4224861