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This paper addresses the issue of heart rate detection from noisy ECG data, and presents a method with low complexity and low memory requirements that can detect QRS complex in the presence of noise and muscle artifacts. On the MIT-BIH arrhythmia database we were able to detect 99.3% of QRS complexes with 0.47% false detection. This method can also be applied to heart rate detection using phonocardio...
In this study, a signal analysis framework based on the Karhunen-Loe've expansion and k-means clustering algorithm is proposed for the characterisation of arteriovenous (AV) fistula's sound recordings. The Karhunen-Loe've (KL) coefficients corresponding to the directions of maximum variance were used as classification features, which were clustered applying k-means algorithm. The results showed that...
Implantable medical devices will play an important role in modern medicine. To reduce the risk of wire snapping, and replacement and corrosion of embedded batteries, wireless delivery of energy to these devices is desirable. However, current autonomous implants remain large in scale due to the operation at very low frequency and the use of unwieldy size of antennas. This paper will show that the optimal...
Wearable body sensor network (WBSN) is realized with wireless and wireline techniques. Body channel communication (BCC), which uses the human body as a signal transmission medium, can reduce energy consumption of a wireless on-body transceiver to less than 0.5 nJ/b. The 3 pulse-based transceivers for BCC are reviewed in this paper, and their interference issues are discussed. To enhance BCC robustness,...
Electrogastrographic examination (EGG) can be considered as a noninvasive method for an investigation of a stomach slow wave propagation. This paper presents a method for determining dominant frequencies. It also shows details of influence of a noise on dominant frequencies determination. The EGG signal is noninvasively captured by appropriately placed electrodes on the surface of the stomach. The...
In this paper, we describe a technique for producing populations of ultrasound contrast agents (UCA) with a narrow size distribution. Using acoustic techniques, we measure the frequency-dependent attenuation coefficient for suspensions of ultrasound contrast agents with varying size distributions, ranging from narrow to wide. Our results demonstrate that as the size distribution becomes more uniform,...
HiLo microscopy is a widefield fluorescence imaging technique that provides depth discrimination by combining two images, one with non-uniform illumination and one with uniform illumination. We discuss the theory of this technique and a variety of practical implementations in brain-tissue imaging and fluorescence endomicroscopy.
Simultaneous seismocardiogram (SCG) and ultra-low frequency ballistocardiogram (BCG) signals are recorded. Preliminary results from the BCG helped tag which waves on the SCG are related to the rapid systolic ejection and aortic valve closure events. These results agreed with and further confirmed previous findings using the echocardiogram. This is the first reported work on comparisons of SCG and...
High frequency ultrasonic imaging is considered by many to be the next frontier in ultrasonic imaging because higher frequencies yield much improved spatial resolution by sacrificing the depth of penetration. It has many clinical applications including visualizing blood vessel wall, anterior segments of the eye and skin. Another application is small animal imaging. Ultrasound is especially attractive...
Electrical cortical stimulation (CS) of the auditory cortices has been shown to reduce the severity of debilitating tinnitus in some patients. In this study, we performed MEG source imaging of spontaneous brain activity during concurrent CS of the left secondary auditory cortex of a volunteer suffering from right unilateral tinnitus. CS produced MEG artifacts which were successfully sorted and removed...
This paper presents a method for synchronous recording and analyzing both the electrogastrographic signal (EGG) and the heart rate variability signal (HRV). The electrogastrographic examination can be considered as a noninvasive method for an investigation of a stomach slow wave propagation. The four channel signal are non-invasively captured by the appropriately placed electrodes on the surface of...
Mechanical characteristics of tumor and healthy tissue in the brain differ but slightly. The task of designing a system that is able to differentiate tissue dignity with high sensitivity is of great importance in neurosurgery. Even when localization of tumor by use of preoperative imaging techniques provides the surgeon with valuable information to decide where and what to resect, the brain shift...
The image and signal correlations are presented for understanding both collective and microscopic dynamics of filamentous bacteirophage, fd-virus suspensions. For a given low ionic strength, the electrostatic Debye screening length is few times larger than the diameter of the core of fd-virus particles; the applied electric field apparently deforms the double-layer and determines the interaction (or...
Neural Gastrointestinal Electrical Stimulation (NGES) is a new microprocessor-based method for invoking gastric or colonic contractions by generating multi-channel, high energy, high frequency waveforms. It has been shown that when applied to the lower stomach, NGES offers the possibility for enhancing propulsive peristalsis for the treatment of gastric motor dysfunctions, or for producing retrograde...
Vagus nerve stimulation (VNS) is an approved therapy for the treatment of adult patients and adolescents aged 12 years and older who have partial onset seizures refractory to antiepileptic medications. More than 50,000 patients worldwide have been implanted with the VNS system. Work continues to understand the mechanism of action of VNS with the goal of improving the treatment, particularly to identify...
Branching conduction networks are responsible for coordinated distribution of activation throughout the heart, but the effects of branching geometry on the efficiency of distribution and the safety of propagation remain unclear. We have developed a simplified computer model to investigate this issue in a systemic fashion. A simplified 2D model that reproduces key features of the right atrial pectinate...
This paper presents a novel approach for designing the front-end of instrumentation amplifiers for use in dry electrode recording of the human electrocardiogram (ECG). The method relies on information provided by the characterization of the skin-electrode interface and the analysis of low frequency ECG criteria defined by international standards. Marginal measurements of capacitive elements of the...
The objective of this exploratory study was to develop signal processing methods for assisting in the diagnosis of arteriovenous fistula stenosis on patients suffering from end-stage renal disease and undergoing haemodialysis treatments. The proposed method is based on the classification of vessels sounds utilizing parameter extraction from wavelets transform coefficients. The coefficients energy...
This study investigates the rate estimation problem encountered in rehabilitation exercise monitoring by using noninvasive portable sensors. The purpose of this paper has two main parts. The first part is to find suitable approaches for the rate detection of tri-axial accelerometer (TA) signals and ECG signals respectively. It is found that the integral type approaches (the average magnitude difference...
This presentation will review the effects of deep brain stimulation (DBS) for movement disorders in patients, and the cellular mechanisms that may explain these effects.
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