Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine This is an RSS file. You can use it to subscribe to this data in your favourite RSS reader or to display this data on your own website or blog.

Nakagami-based total variation method for speckle reduction in thyroid ultrasound images
A good statistical model is necessary for the reduction in speckle noise. The Nakagami model is more general than the Rayleigh distribution for statistical modeling of speckle in ultrasound images. In this article, the Nakagami-based noise removal method is presented to enhance thyroid ultrasound images and to improve clinical diagnosis. The statistics of log-compressed image are derived from the Nakagami distribution following a maximum a posteriori estimation framework. The minimization problem is solved by optimizing an augmented Lagrange and Chambolle’s projection method. The proposed method is evaluated on both ...
Source: Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine - January 18, 2016 Category: Biomedical Engineering Authors: Koundal, D., Gupta, S., Singh, S. Tags: Original Articles Source Type: research

Hemodynamic study of the elliptic St. Jude Medical valve: A computational study
In this study, we evaluated the hemodynamics around the leaflets in the opening phase using a more sophisticated computational platform, computational fluid dynamics. Results suggested both lower shear stress and wall shear stress values and an overall improved hemodynamic performance in the proposed design. This improvement is characterized by lower values of shear stress and wall shear stress in the regions downstream of the leaflets, lower pressure drop across the valve and smaller recirculation zones in the sinuses areas. The proposed design may open a new chapter in the concept of design and hemodynamic improvement of...
Source: Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine - January 18, 2016 Category: Biomedical Engineering Authors: Jahandardoost, M., Fradet, G., Mohammadi, H. Tags: Original Articles Source Type: research

Morphological and mechanical properties of the posterior leaflet chordae tendineae in the mitral valve
This study contributes to the literature by comparing the failure load of the chordae tendineae attached to the three posterior leaflet scallops, the anterolateral scallop (P1), middle scallop (P2), and posteromedial scallop (P3) of the mitral valve. In all, 140 chordae isolated from 23 porcine hearts were tested. First, the cross-sectional diameters of all branches in each chorda were measured using a microscope. Next, after positioning the chorda in a tensile testing machine, a preload of 0.2 N was applied, and the chordal length was measured. Cyclic loading between 0 and 0.3 N, 10 times with a speed of 1.5 mm/s, was con...
Source: Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine - January 18, 2016 Category: Biomedical Engineering Authors: Lodder, J., Verkerke, G. J., Delemarre, B. J., Dodou, D. Tags: Original Articles Source Type: research

Evaluation of ventricular wall stress and cardiac function in patients with dilated cardiomyopathy
Dilated cardiomyopathy is a heart disease characterized by both left ventricular dilatation and left ventricular systolic dysfunction, leading to cardiac remodeling and ultimately heart failure. We aimed to investigate the effect of dilated cardiomyopathy on the pump performance and myocardial wall mechanics using patient-specific finite element analysis. Results evinced pronounced end-systolic wall stress on left ventricular wall of patients with dilated cardiomyopathy as compared to that of normal hearts. In dilated cardiomyopathy, both end-diastolic and end-systolic pressure–volume relationships of left ventricle ...
Source: Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine - December 30, 2015 Category: Biomedical Engineering Authors: Scardulla, F., Rinaudo, A., Pasta, S., Scardulla, C. Tags: Technical Note Source Type: research

Three-dimensional lung nodule segmentation and shape variance analysis to detect lung cancer with reduced false positives
The three-dimensional analysis on lung computed tomography scan was carried out in this study to detect the malignant lung nodules. An automatic three-dimensional segmentation algorithm proposed here efficiently segmented the tissue clusters (nodules) inside the lung. However, an automatic morphological region-grow segmentation algorithm that was implemented to segment the well-circumscribed nodules present inside the lung did not segment the juxta-pleural nodule present on the inner surface of wall of the lung. A novel edge bridge and fill technique is proposed in this article to segment the juxta-pleural and pleural-tail...
Source: Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine - December 30, 2015 Category: Biomedical Engineering Authors: Krishnamurthy, S., Narasimhan, G., Rengasamy, U. Tags: Original Articles Source Type: research

Friction in modern total hip arthroplasty bearings: Effect of material, design, and test methodology
The purpose of this study was to characterize the effect of a group of variables on frictional torque generated by acetabular components as well as to understand the influence of test model. Three separate test models, which had been previously used in the literature, were used to understand the effect of polyethylene material, bearing design, head size, and material combinations. Each test model differed by the way it simulated rotation of the head, the type of frictional torque value it reported (static vs. dynamic), and the type of motion simulated (oscillating motion vs. continuous motion). It was determined that not o...
Source: Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine - December 30, 2015 Category: Biomedical Engineering Authors: Scholl, L., Longaray, J., Raja, L., Lee, R., Faizan, A., Herrera, L., Thakore, M., Nevelos, J. Tags: Original Articles Source Type: research

Effect of friction and clearance on kinematics and contact mechanics of dual mobility hip implant
The dual mobility hip implant has been introduced recently and increasingly used in total hip replacement to maintain the stability and reduce the risk of post-surgery dislocation. However, the kinematics and contact mechanisms of dual mobility hip implants have not been investigated in detail in the literature. Therefore, finite element method was adopted in this study to investigate dynamics and contact mechanics of a typical metal-on-polymer dual mobility hip implant under different friction coefficient ratios between the inner and the outer articulations and clearances/interferences between the ultra-high-molecular-wei...
Source: Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine - December 30, 2015 Category: Biomedical Engineering Authors: Gao, Y., Chai, W., Wang, L., Wang, M., Jin, Z. Tags: Original Articles Source Type: research

Individual and combined effects of noise-like whole-body vibration and parathyroid hormone treatment on bone defect repair in ovariectomized mice
The effectiveness of intermittent administration of parathyroid hormone and exposure to whole-body vibration on osteoporotic fracture healing has been previously investigated, but data on their concurrent use are lacking. Thus, we evaluated the effects of intermittent administration of parathyroid hormone, whole-body vibration, and their combination on bone repair in osteoporotic mice. Noise-like whole-body vibration with a broad frequency range was used instead of conventional sine-wave whole-body vibration at a specific frequency. Mice were ovariectomized at 9 weeks of age and subjected to drill-hole surgery in the right...
Source: Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine - December 30, 2015 Category: Biomedical Engineering Authors: Matsumoto, T., Sato, D., Hashimoto, Y. Tags: Original Articles Source Type: research

Pulse-echo ultrasound transit time spectroscopy: A comparison of experimental measurement and simulation prediction
In this study, the same samples were used but in pulse-echo mode, where the same ultrasound transducer served as both transmitter and receiver, detecting both ‘primary’ (internal sample interface) and ‘secondary’ (external sample interface) echoes. A transit time spectrum was derived, describing the proportion of sonic rays with a particular transit time. A computer simulation was performed to predict the transit time and amplitude of various echoes created, and compared with experimental data. Applying an amplitude-tolerance analysis, 91.7% ± 3.7% of the simulated data were within ±1 ...
Source: Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine - December 30, 2015 Category: Biomedical Engineering Authors: Wille, M.-L., Almualimi, M. A., Langton, C. M. Tags: Original Articles Source Type: research

A biomechanical comparison of four different fixation methods for midshaft clavicle fractures
Clavicle fractures may occur in all age groups, and 70%–80% of clavicle fractures occur in the midshaft. Many methods for treating midshaft clavicular fractures have been reported and remain controversial. To provide some guidance for clinical treatment, 30 artificial polymethyl methacrylate models of the clavicle were sewn obliquely at the midshaft to simulate the most common type of clavicular fractures, and the fracture models were divided into five groups randomly and were fixed as follows: the reconstruction plates were placed at the superior position of the fracture model (R-S group), the reconstruction plates ...
Source: Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine - December 30, 2015 Category: Biomedical Engineering Authors: Chen, Y., Yang, Y., Ma, X., Xu, W., Ma, J., Zhu, S., Ma, B., Xing, D. Tags: Original Articles Source Type: research

The influence of metallic shell deformation on the contact mechanics of a ceramic-on-ceramic total hip arthroplasty
Total hip arthroplasty of ceramic-on-ceramic bearing combinations is increasingly used clinically. The majority of these implants are used with cementless fixation that a metal-backing shell is press-fitted into the pelvic bone. This usually results in the deformation of the metallic shell, which may also influence the ceramic liner deformation and consequently the contact mechanics between the liner and the femoral head under loading. The explicit dynamic finite element method was applied to model the implantation of a cementless ceramic-on-ceramic with a titanium shell and subsequently to investigate the effect of the me...
Source: Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine - December 30, 2015 Category: Biomedical Engineering Authors: Qiu, C., Wang, L., Li, D., Jin, Z. Tags: Original Articles Source Type: research

Editorial
(Source: Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine)
Source: Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine - December 30, 2015 Category: Biomedical Engineering Tags: Editorial Source Type: research

Hydrogels for central nervous system therapeutic strategies
The central nervous system shows a limited regenerative capacity, and injuries or diseases, such as those in the spinal, brain and retina, are a great problem since current therapies seem to be unable to achieve good results in terms of significant functional recovery. Different promising therapies have been suggested, the aim being to restore at least some of the lost functions. The current review deals with the use of hydrogels in developing advanced devices for central nervous system therapeutic strategies. Several approaches, involving cell-based therapy, delivery of bioactive molecules and nanoparticle-based drug deli...
Source: Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine - November 24, 2015 Category: Biomedical Engineering Authors: Russo, T., Tunesi, M., Giordano, C., Gloria, A., Ambrosio, L. Tags: Special Issue Articles Source Type: research

Effect of calcium/sodium ion exchange on the osmotic properties and structure of polyelectrolyte gels
We discuss the main findings of a long-term research program exploring the consequences of sodium/calcium ion exchange on the macroscopic osmotic and elastic properties, and the microscopic structure of representative synthetic polyelectrolyte (sodium polyacrylate, (polyacrylic acid)) and biopolymer gels (DNA). A common feature of these gels is that above a threshold calcium ion concentration, they exhibit a reversible volume phase transition. At the macroscopic level, the concentration dependence of the osmotic pressure shows that calcium ions influence primarily the third-order interaction term in the Flory–Huggins...
Source: Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine - November 24, 2015 Category: Biomedical Engineering Authors: Horkay, F., Basser, P. J., Hecht, A.-M., Geissler, E. Tags: Special Issue Articles Source Type: research

Kinetics of aqueous lubrication in the hydrophilic hydrogel Gemini interface
The exquisite sliding interfaces in the human body share the common feature of hydrated dilute polymer mesh networks. These networks, especially when they constitute a sliding interface such as the pre-corneal tear film on the ocular interface, are described by the molecular weight of the polymer chains and a characteristic size of a minimum structural unit, the mesh size, . In a Gemini interface where hydrophilic hydrogels are slid against each other, the aqueous lubrication behavior has been shown to be a function of sliding velocity, introducing a sliding timescale competing against the time scales of polymer fluctuatio...
Source: Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine - November 24, 2015 Category: Biomedical Engineering Authors: Dunn, A. C., Pitenis, A. A., Uruena, J. M., Schulze, K. D., Angelini, T. E., Sawyer, W. G. Tags: Special Issue Articles Source Type: research