OBJECTIVE To study reproducibility of f-wave parameters in terms of inter- and intrapatient variation. APPROACH Five parameters are investigated dominant atrial frequency (DAF), f-wave amplitude, phase dispersion, spectral organization, and spatiotemporal variability. For each parameter, the variance ratio R, defined as the ratio between inter- and intrapatient variance, is computed; a larger R corresponds to better stability and reproducibility. The study population consists of 20 high-quality ECGs recorded from patients with atrial fibrillation (11/9 paroxysmal/persistent). MAIN RESULTS The well-established parameters DAF and f-wave amplitude were associated with considerably larger R-values (13.1 and 21.0, respectively) than phase dispersion (2.4), spectral organization (2.4), and spatiotemporal variability (2.7). The use of an adaptive harmonic frequency tracker to estimate the DAF resulted in a larger R (13.1) than did block-based maximum likelihood estimation (6.3). SIGNIFICANCE This study demonstrates a noticeable difference in reproducibility among f-wave parameters, a result which should be taken into account when performing f-wave analysis. Light effects have been frequently used in volume rendering because they can depict the shapes of objects more realistically. Global illumination reflects light intensity values at relevant pixel positions of reconstructed images based on the considerations of scattering and extinction phenomena. However, in the cases of ultrasound volumes that do not use Cartesian coordinates, internal lighting operations generate errors owing to the distorted direction of light propagation, and thus increase the amount of light and its effects according to the position of the volume inside. selleck products In this study, we present a novel global illumination method with calibrated light along the progression direction in accordance with volume ray casting in non-Cartesian coordinates. In addition, we reduce the consumption of lighting operation in these lighting processes using a light-distribution template. Experimental results show the volume rendering outcomes in non-Cartesian coordinates that realistically visualize the global illumination effect. The light scattering effect is expressed uniformly in the top and bottom areas where many distortions are generated in the ultrasound coordinates by using the light template kernels adaptively. Our method can effectively identify dark areas that are invisible owing to differences in brightness at the upper and lower regions of the ultrasound coordinates. Our method can be used to realistically show the shapes of the fetus during relevant examinations with ultrasonography. In this paper, we investigate the heating function of the nasal cavity qualitatively, using a high-quality, large-scale statistical shape model. This model consists of a symmetrical and an asymmetrical part and provides a new and unique way of examining changes in nasal heating function resulting from natural variations in nasal shape (as obtained from 100 clinical CT scans). Data collected from patients suffering from different nasal or sinus-related complaints are included. Parameterized models allow us to investigate the effect of continuous deviations in shape from the mean nasal cavity. This approach also enables us to avoid many of the compounded effects on flow and heat exchange, which one would encounter when comparing different patient-specific models. The effects of global size, size-related features, and turbinate size are investigated using the symmetrical shape model. The asymmetrical model is used to investigate different types of septal deviation using Mladina's classification. The qualitative results are discussed and compared with findings from the existing literature. Using electrospun fibers to deliver therapeutic agents has gained significant attention in various applications including cancer treatment and tissue regeneration. However, the effect of fluid flow and uptake by cells on the concentration profile is not well understood. In this study, we evaluated the release of lipophilic resveratrol from poly(ε-caprolactone) (PCL)-gelatin (GT) electrospun fibers experimentally and by using computational fluid dynamics (CFD). Resveratrol containing PCL-GT electrospun fibers were formed and used in a custom-built tubular bioreactor, to assess flow effect on concentration profile over 5 days. CFD model was developed to simulate release in both static cultures and under fluid flow conditions. Resveratrol stability in the culture medium and uptake by human umbilical vein endothelial cells and K562 cells over 3 days were used in the model. The concentration profile as a function of time was simulated and validated by experiments. The effects of inlet velocity, cellular uptake rate, bioreactor's length, and surrounding tissue porosity were assessed. The release profile was mainly affected by cellular uptake and the presence of porous media. The model suggests that the perfusion velocity might not have a significant effect relative to the cellular uptake rate and porosity of the surrounding tissue. Recognition and analysis of Diabetic Foot Ulcers (DFU) using computerized methods is an emerging research area with the evolution of image-based machine learning algorithms. Existing research using visual computerized methods mainly focuses on recognition, detection, and segmentation of the visual appearance of the DFU as well as tissue classification. According to DFU medical classification systems, the presence of infection (bacteria in the wound) and ischaemia (inadequate blood supply) has important clinical implications for DFU assessment, which are used to predict the risk of amputation. In this work, we propose a new dataset and computer vision techniques to identify the presence of infection and ischaemia in DFU. This is the first time a DFU dataset with ground truth labels of ischaemia and infection cases is introduced for research purposes. For the handcrafted machine learning approach, we propose a new feature descriptor, namely the Superpixel Colour Descriptor. Then we use the Ensemble Convolutional Neural Network (CNN) model for more effective recognition of ischaemia and infection.selleck products
For further actions, you may consider blocking this person and/or reporting abuse
Top comments (0)