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Analysis of biomedical images requires attention to image features that represent a small fraction of the total image size. A rapid method for eliminating unnecessary detail, analogous to pre-attentive processing in biological vision, allows computational resources to be applied where most needed for higher-level analysis. In this report we describe a method for bottom up merging of pixels into larger...
In this paper, we present a stretchable electrode array for studying cell behavior subjected to mechanical strain. The electrode array consists of four gold nail-head pins (250 mum tip diameter and 1.75 mm spacing) inserted into a polydimethylsiloxane (PDMS) platform (25.4 times 25.4 mm2). Fusible indium alloy (liquid at room temperature) filled microchannels are used to connect the electrodes to...
Recently, novel near-infrared (NIR) voltage-sensitive dyes were developed for imaging electrical activity in blood-perfused hearts and for tomographic applications. However, their usefulness for conventional surface mapping is unclear. The spectral shift to the NIR range significantly increases the penetration depth of light into the tissue, thus increasing the intramural volume contributing to the...
The X-Delta model for through-skin volume conduction systems is introduced and analyzed. This new model has advantages over our previous X model in that it explicitly represents current pathways in the skin. A vector network analyzer is used to take measurements on pig skin to obtain data for use in finding the model's impedance parameters. An optimization method for obtaining this more complex model's...
We studied the mechanisms of spontaneous termination of atrial fibrillation in a biophysical model of human atria, during the eight seconds preceding termination. The earliest detectable changes in the cycle length and the number of wavefronts occurred about three seconds prior to termination. We compared the mechanisms involved in the right and left atrium and investigated the effects of atrial geometry...
A novel optical non-invasive in vivo blood glucose concentration (BGL) measurement technique, named ldquopulse glucometryrdquo, was combined with a kernel method; support vector machines. The total transmitted radiation intensity (Ilambda) and the cardiac-related pulsatile changes superimposed on Ilambda in human adult fingertips were measured over the wavelength range from 900 to 1700 nm using a...
In this paper, the influence of the finger posture on the subjective effort during pinching motion is investigated by using a tendon-skeletal finger model. The experimental results show that the subjective effort human feels is affected by the size of the object he/she pinches, and the subjective effort correlates with the finger length. The simulation results show that the pattern of the tendon forces...
Photonic crystal surfaces are demonstrated as a means for enhancing the detection sensitivity and resolution for assays that use a fluorescent tag to quantify the concentration of an analyte protein molecule in a liquid test sample. Computer modeling of the spatial distribution of resonantly coupled electromagnetic fields on the photonic crystal surface are used to estimate the magnitude of enhancement...
Cross-sectional imaging of an electrical conductivity distribution inside the human body has been an active research topic in the field of impedance imaging. This paper describes the recent progress in magnetic resonance electrical impedance tomography (MREIT) where conductivity imaging with a spatial resolution of a few mm is pursued. After the early studies on its theory and image reconstruction...
Previous research has shown that hypothermia immediately after Cardiac Arrest (CA) improves neurological outcomes. In order to study how hypothermia affects neural spiking, cortical and subcortical neural activity was recorded from rodents. Consistent with previous findings, preliminary results show that the firing rate is proportional to the temperature. We also studied the information coded in the...
Previous works on the effects of salivary alpha amylase in respond to various stressors report encouraging findings on it being a good indicator of stress. Ellestad protocol is a clinical procedure to screen for coronary artery disease by introducing exercise induced physical stress. If a salivary based biomarker profile in accordance to a stress test protocol could be established, the critical stress...
Vibration has been increasingly sought after as new technique, due to its potential to increase muscle strength and positively affect bone remodeling. Currently, there are many vibration devices on the market advertised for different applications, in particular in sports and rehabilitation. All the available devices have two major drawbacks; firstly, they are not sufficiently adaptive to the individual...
Transcranial direct current stimulation (tDCS) is a non-invasive procedure where a weak electrical current is applied across the scalp to modulate brain function. The proliferation of this therapy has been accompanied by isolated reports regarding concern about their safety namely skin irritation. The potential cause of skin irritation has sometimes been attributed to increased scalp temperature during...
Quantitative images of high-frequency (>20 MHz) power Doppler ultrasound can be difficult to obtain in the presence of flow artifacts due to power Doppler's sensitivity to operator-dependent acquisition settings. To improve flow quantification, color pixel density (CPD) can be plotted as a function of wall filter cut-off velocity to produce a wall-filter selection curve that can be used to estimate...
In recent years, the monitoring of sitting postures was discovered to be a promising measure of healthy sitting behavior, comfort, physical wellness and emotions. Most state-of-the-art systems for monitoring sitting behavior are based on supervised methods that are limited to a fixed set of classes. We present a method that does not rely on training but distinguishes between different postures autonomously...
An abled individual is believed to be capable of withstanding and overcoming the severe tremors of an earthquake as has been ascertained in a previous study. However, the event-related physiological mechanisms of human postural stability during an earthquake are subject to further investigation. Accordingly, the objective of this study is to further characterize postural stability in a simulated environment...
The paper includes illustrative and detailed information about implementation of automated diagnostic systems and feature extraction/selection from signals recorded from ophthalmic arteries. The major objective of the paper is to be a guide for the readers, who want to develop an automated diagnostic systems for detection of arterial disorders. Toward achieving this objective, this paper present the...
In an effort to make activity monitors usable by manual wheelchair users with spinal cord injury (SCI), our study examines the validity of SenseWearreg Armband (SenseWear) and RT3 in assessing energy expenditure (EE) during wheelchair related activities. This paper presents the data obtained from six subjects (n=6) with SCI performing three activities, including wheelchair propulsion, armergometer...
This paper presents the design and measurements of a low noise multi-channel front-end electronics for recording extra-cellular neuronal signals using microelectrode arrays. The integrated circuit contains 64 readout channels and was fabricated in CMOS 0.18 mum technology. A single readout channel is built of an AC coupling circuit at the input, a low noise preamplifier, a band-pass filter and a second...
Electromyogram (EMG) pattern recognition approach has been investigated widely with able-bodied subjects for control of multifunctional prostheses and verified with high performance in identifying different movements. However, it remains unclear whether transradial amputees can achieve similar performance. In this study, we investigated the performance of EMG pattern recognition control of multifunctional...
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