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The successful salvage of a free flap is dependent on the continuous monitoring of perfusion. To date there is no widely accepted and readily available post-operative monitoring technique to reliably assess the viability of free flaps by continuously monitoring free flap blood oxygen saturation. In an attempt to overcome the limitations of the current techniques a reflectance photoplethysmographic...
In this study, finger photoplethysmograph data obtained from twelve patients undergoing cardiothoracic surgery were analyzed in order to estimate the venous saturation utilizing the modulations created by the positive pressure ventilation in the AC Photoplethysmograph (PPG) signals. The PPG signals were analyzed in the time-domain using a conventional pulse oximetry algorithm to produce estimations...
Spectral analysis of Heart Rate Variability (HRV) is used for the assessment of cardiovascular autonomic control. In this study Continuous Wavelet Transform (CWT) has been used to evaluate the effect of local anesthesia on HRV parameters in a group of fourteen patients undergoing axillary brachial plexus block. A new method which takes signal characteristics into account has been presented for the...
Pulse oximetry utilises the technique of photople-thysmography (PPG) to estimate arterial oxygen saturation values (SpO2). In poorly perfused tissues, SpO2 readings may be compromised due to the poor quality of the PPG signals. In order to investigate further the threshold where pulse oximetry fails to produce accurate SpO2 values, we have developed a custom made multimode finger pulse oximetry probe...
Monitoring of free flap perfusion and early identification of flap failure is an indispensable prerequisite for flap salvage. Although many methods of free flap monitoring are available, there is still no single reliable continuous non-invasive perfusion monitoring technique which will also assist in the early recognition of flap failure. In order to overcome the current technological limitations,...
A new method of measuring image contrast based on local band-limited approach and center-surround retinal receptive field model is devised in this paper. Various evidences from physiological studies corresponding to contrast perception is considered. This method works at multiple scales (frequency bands) and combines the contrast measures obtained at different scales using Lp-norm. Demonstrations...
Histogram equalization, which aims at information maximization, is widely used in different ways to perform contrast enhancement in images. In this paper, an automatic exact histogram specification technique is proposed and used for global and local contrast enhancement of images. The desired histogram is obtained by first subjecting the image histogram to a modification process and then by maximizing...
This article provides an overview of the application of certain soft computing tools namely, genetic algorithms (GAs), simulated annealing (SA), and artificial neural networks (ANNs) in certain tasks of RNA secondary structure prediction. Different tasks like prediction of helix, bulge, hairpin curve, internal loop, and multiloop are, first of all, described along with their basic features. The relevance...
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