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A model for the simulation of motoneuron firing behavior and muscle force during sustained constant-force isometric contractions was developed. It provides a non-linear relationship between the excitation to the motoneuron pool of a muscle and the firing behavior of motor units; it implements muscle mechanical changes induced by fatigue and it comprises a feedback loop to maintain the muscle force...
In order to provide natural, biomimetic control to recently developed powered ankle prostheses, we must characterize the impedance of the ankle during ambulation tasks. To this end, a platform robot was developed that can apply an angular perturbation to the ankle during ambulation and simultaneously acquire ground reaction force data. In this study, we detail the design of the platform robot and...
The natural non-spherical incongruent hip joint cartilage surface is normally assumed as spherical in shape, which has been extensively applied in orthopedic clinic, hip joint simulation studies and hip joint prosthesis design. The aim of the study was to investigate the contributions of non-spherical incongruent hip joint cartilage surface to the hip joint contact stress, and to assess the effect...
The Rush head model is an approximation of the volume conducting properties of the human head. A planar saline bath phantom was developed to simulate the key properties of the Rush head model while creating a testing platform for implantable neural devices. The phantom closely mimics electrical properties of human tissue such as increased resistivity through the skull region and current flow that...
This paper presents an extensible distributed platform that aims to speed up the development of personalized telemedicine systems, dealing with a series of recurrent problems in this kind of system, particularly: (1) functionality encapsulation and reuse in a set of services; (2) communications between the patient's home and the hospital, through a flexible scheme for bidirectional message exchange;...
Continued miniaturization of electronic devices and technological advancements in wireless communications has made wearable body-centric telemedicine systems viable. Antennas play a crucial role in characterizing the efficiency and reliability of these systems. The performance characteristics such as the radiation pattern, gain, efficiency of the antennas get adversely affected due to the presence...
Several algorithms have been recently proposed for the analysis of dermoscopy images and the detection of melanomas. However, the pigment network is not considered in most of these works, although this cue plays a major role in clinical diagnosis routines. This paper proposes an algorithm for the detection of the pigment network. The algorithm is based on a bank of directional filters (difference...
This paper introduces a new quantification method for gait symmetry based on depth information acquired from a structured light system. First, the new concept of Depth Energy Image is introduced to better visualize gait asymmetry problems. Then a simple index is computed from this map to quantify motion symmetry. Results are presented for six subjects with and without gait problems. Since the method...
This paper presents a study that investigated the potential of texture analysis using Fluid Sensitive Fat Suppressed MRI images for the use in detection of bone marrow edema. A total of 168 slices of knee MRI from 10 subjects were involved. Six histogram-based textures (mean intensity, standard deviation, smoothness, third moment, uniformity and entropy) were calculated in both 2D and 3D, and were...
The intima-media thickness of the carotid artery (CIMT) is a validated marker of atherosclerosis. Accurate CIMT measurement can be performed by specifically designed computer algorithms. We improved a previous CIMT measurement technique by introducing a smart heuristic search for the lumen-intima (LI) and media-adventitia (MA) interfaces of the carotid distal wall. We called this new release as CARES...
Navigation and way finding including obstacle avoidance is difficult when visual perception is limited to low resolution, such as is currently available on a bionic eye. Depth visualisation may be a suitable alternative. Such an approach can be evaluated using simulated phosphenes with a wearable mobile virtual reality kit. In this paper, we present two novel approaches: (i) an implementation of depth...
An extended registration model is presented to register medical image triples acquired for brain dopamine receptor scintigraphies. The model operates with rigid and nonlinear transformations in parallel, where all transformation parameters are optimized by one optimization method. The concept of the transformation-sampling-similarity measurement minimizes the memory usage of a real implementation...
Our purpose in this study is to segment the rectus abdominis muscle region in X-ray CT images, and we propose a novel recognition method based on the shape model. In this method, three steps are included in the segmentation process. The first is to generate a shape model for the rectus abdominis muscle. The second is to recognize anatomical feature points corresponding to the origin and insertion...
Viability assessment of heart muscle after a myocardial infarction is an important step for diagnosis and therapy planning. It is important to quantify the area of edema because it can differentiate between viable and death myocardial tissues. In this paper an automatic method to quantify cardiac edema is presented. The method is based on a combination of morphological operations and statistical thresholding...
The segmentation of three-dimensional vascular trees is an important topic in medical image processing. Although it may seem to be an easy task, many different techniques have been proposed in the literature during the last decade and many difficulties remain. One can wonder why the human eye is usually able to understand the connectivity and the topology of the different structures while most algorithms...
Electroencephalography (EEG) and magneto-encephalography (MEG) are both currently used to reconstruct brain activity. The performance of inverse source reconstructions is dependent on the modality of signals in use as well as inverse techniques. Here we used a recently proposed sparse source imaging technique, i.e., the variation-based sparse cortical current density (VB-SCCD) algorithm to compare...
3D functional neuroimaging is used in the diagnosis and management of neurological disorders. The efficient management and analysis of these large imaging datasets has prompted research in the field of content-based image retrieval. In this context, our generalized regional disorder-sensitive-weighting (DSW) scheme gives greater weight to brain regions affected by the diseases than regions that are...
This study explored the feasibility of high-resolution Mn-enhanced MRI (MEMRI) and diffusion tensor imaging (DTI) for in vivo assessments of the development and reorganization of retinal and visual callosal pathways in normal neonatal rodent brains and after early postnatal visual impairments. Using MEMRI, intravitreal Mn2+ injection into one eye resulted in maximal T1-weighted hyperintensity in neonatal...
The effect of increasing the number of scans in the “cluster” of an interleaved silent steady state (ISSS) fMRI imaging scheme from 1 to 2, and then to 3 was examined by a fixed-effects analysis of an auditory short-term memory task with four subjects. Compared to a cluster size of 1, a cluster of 2 scans improved sensitivity at detecting brain activity and statistical power, while a cluster of 3...
Magnetic Resonance Electrical Impedance Tomography (MREIT) produces cross-sectional images of a conductivity distribution inside the human body. We use an MRI scanner as a tool to measure induced internal magnetic flux density distributions subject to externally injected currents. Recent experimental MREIT studies demonstrated conductivity image reconstructions of in vivo animal and human subjects...
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