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Three quantitative and non-invasive techniques were used to monitor angiogenesis in Kaposi's sarcoma patients: thermography, laser Doppler imaging (LDI), and near-infrared spectroscopy. Before and after combination cytotoxic and anti-angiogenesis therapy, blood volume, oxygenated hemoglobin, temperature, and blood flow were analyzed. These three techniques are objective, easy to perform, and appear...
In recent years there has been a resurgence of interest in the application of infrared thermal imaging in medicine. Yet fairly little effort has been spent towards standardisation of the field and a common communication and exchange format for thermal images. Most other medical areas where digital imaging is employed have subscribed to DICOM (Digital Imaging and COmmunication in Medicine) as a common...
In this paper, the results of both normal-hearing, and profoundly hearing-impaired adults, tested with spectrum compressed speech via the modified chirp-z algorithm, with and without visual stimuli, are reported. Ten normal-hearing adult listeners and five profoundly hearing-impaired adult listeners were asked to identify nonsense syllables presented auditorily and bimodally (audition and vision)...
A method is presented to validate the segmentation of computed tomography (CT) image sequences, and improve the accuracy and efficiency of the subsequent registration of the 3D surfaces that are reconstructed from the segmented slices. The method compares the shapes of contours extracted from neighborhoods of slices in CT stacks of tibias. The bone is first segmented by an automatic segmentation technique,...
An optical sensor integrated into a polymer microfluidic chip is proposed as a low cost solution to highly parallel biochemical analysis. The sensor consists of a single high-finesse optical resonator for direct analytes detection. High quality silica microspheres (diameter 300 ??m) are easily produced and low-loss whispering gallery modes were excited through evanescent coupling at wavelengths near...
The processing components and the dynamic signaling network that an individual cell uses to do signal integration and make decisions based on multiple sensory inputs are being identified in a well studied free-swimming unicellular green algal model organism, Chlamydomonas. It has many sensory photoreceptors and measurable behavior associated with its orienting and swimming with respect to light sources...
Here we show how nonlinear system identification techniques, such as fast orthogonal search (FOS) and the orthogonal search method (OSM), can be used to analyze gene expression profiles and predict the class to which a profile belongs.
Current density imaging (CDI) is a technique that uses magnetic resonance imaging (MRI) to measure the distribution of externally applied electric current inside tissues. However, CDI processing is rendered inaccurate by the distortion caused by the nonlinearity of MRI gradient fields. The distortion interferes with the proper registration and the curl operation required for correct computation of...
This paper presents a parallel-computing FDTD simulator for electromagnetic analysis and design applications in Magnetic Resonance Imaging system. It is intended to be a complete, high-performance FDTD model of an MRI system including all temporal RF and low-frequency field generating units and electrical models of the patient. The developed MRI-dedicated FDTD algorithm is adapted to a parallel computing...
Eddy currents induced within a Magnetic Resonance Imaging (MRI) cryostat bore during pulsing of gradient coils can be applied constructively together with the gradient currents that generate them, to obtain good quality gradient uniformities within a specified imaging volume over time. This can be achieved by simultaneously optimizing the spatial distribution and temporal pre-emphasis of the gradient...
Concerns have been expressed about safety of MRI examination of two groups of people, namely pregnant mothers and cardiac pacemaker bearers. The main uncertainty relates to excessive heating by pulsed radio frequency (RF) fields. To address these issues, numerical evaluations of the power deposition are performed for a 27-week old fetus in a simplified model of the mother, and a realistic model of...
This paper presents an analysis of the effect of RF apodization for parallel spatially selective excitation in MRI. Using the small tip-angle approximation and the k-space interpretation, the analysis shows that for multidimensional multi-channel parallel excitation, limited RF pulse duration can lead to ringing excitation artifacts, similar to the truncation artifacts. Proper weighting of RF pulses...
Spectrometer is the essential part of magnetic resonance imaging (MRI) system. It controls the transmitting and receiving of signals. Many commercial spectrometers are now available. However, they are usually costly and complex. In this paper, a new digital spectrometer based on PCI extensions for instrumentation (PXI) architecture is presented. Radio frequency (RF) pulse is generated with the method...
Twenty subjects, 10 adults and ten children were tested in this study. Each test consisted of applying an ensemble of velocities to the lower limb using a torque motor in such a way that the entire range of motion of the knee was traversed. Eight velocities between 60 deg/sec and 280 deg/sec were reached at 2-3 different acceleration rates and 1-2 different rates of jerk. EMG from three muscles, vastus,...
We have developed a time-varying, parallel-cascade system identification algorithm to separate joint stiffness into intrinsic and reflex components at each point in time throughout rapid movements. The components are identified using an iterative algorithm in which intrinsic and reflex dynamics are identified using separate time-varying (TV) techniques based on ensemble methods. An ensemble of input-output...
Joint stiffness is defined as the dynamic relationship between the position of the joint and torque acting about it. Joint stiffness is composed of two components: intrinsic and reflex stiffness. Measuring the two stiffness components cannot be done simply because the two components appear and change together. A number of approaches have been used to estimate the components, but all those approaches...
Joint stiffness, defined as the relation between the angular position of a joint and the torque acting about it, can be used to describe the dynamical behavior of the human ankle during posture and movement. Joint stiffness can be separated into intrinsic stiffness and reflex stiffness, which are modeled as a linear system and a Hammerstein system, respectively. A two-pathway parallel cascade model,...
The purpose of this study was to examine how multijoint stretch reflexes are modulated during interactions with stiff and compliant environments. Reflex responses were elicited using a 3D robotic manipulator to perturb arm posture in the three degrees of freedom relevant to functional behaviors. The robot applied controlled displacements and simulated environments with different stiffnesses. Stiff...
We studied the neuromuscular mechanical properties of the elbow and ankle joints in chronic, hemiparetic stroke patients and healthy subjects. System identification techniques were used to characterize the mechanical abnormalities of these joints and to identify the contribution of intrinsic and reflex stiffness to these abnormalities. Modulation of intrinsic and reflex stiffness with the joint angle...
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