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A method has been developed to determine the incremental nonlinear elastic anisotropic material properties of skin. The method requires the solution of an overdetermined nearly singular system of equations. Two solution techniques, weighted averaging and singular value decomposition (SVD), are applied to data obtained from rat skin. The SVD method appears to be more accurate.<<ETX>>
A study was initiated to mechanically and histologically examine chemically processed patellar tendon allografts in sheep anterior cruciate ligament (ACL) repairs. One group of animals received frozen grafts that were processed with a chloroform/methanol solvent extraction technique, and a third sheep group received frozen tendons treated with a permeation enhanced extraction technique. Histologic...
The authors outline the design, construction, and calibration of a combination turbidimeter/nephelometer system using fiber-optic technology. Calibration was done by means of a Formazin standard in the nephelometric system. By using the Formazin results as standards to calibrate the turbidimeter, the turbidity of an unknown can be obtained for a given wavelength. It is pointed out that the system...
Receptor function is being investigated by incorporating naturally occurring membrane-based biological recognition elements into surface structures interfaced with microelectronic substrates. Alkylsilane molecules, formulating one half of a bilayer membrane mimetic structure, were covalently bound to the surface of Si/SiO/sub 2/ electrodes and interdigitated microsensor electrode devices. In addition...
A diode laser and fiber optics have been successfully incorporated in a compact, low-cost micro laser Doppler velocimeter. Preliminary experiments show good results for measuring velocity and provide a promising future for measuring blood flow. The micro laser Doppler flowmeter will provide a low-cost, more compact alternative to existing laser Doppler flowmeters.<<ETX>>
The feasibility of accurate prediction of physiological glucose concentration in phosphate buffered saline (PBS) solutions with a pH of 7.4, maintained at 37 degrees C, was demonstrated by applying univariate and multivariate statistical methods to their mid-infrared spectra (1500-800 cm/sup -1/). Multivariate methods, partial least squares, and principal components regression produced calibration...
The authors point out that current techniques for the quantification of blood glucose, particularly in the home environment, have lacked precision. In their investigations into the rotary effects of glucose upon the polarization vector of light, the authors have developed a polarimeter capable of microdegree precision. At the present sensitivity, normal physiological levels of blood glucose could...
An analytical model was developed to predict the specific absorption rate (SAR) pattern of helical antennas in a general medium. Experimental measurements verified the accuracy of the model and revealed the complicated nature of the heating pattern. The calculated and measured results show a distinct standing wave pattern along the length of the antenna, whose wave number depends strongly on the helical...
Bone remodeling in the vicinity of implants was evaluated by scanning acoustic microscopy. The degree of remodeling was determined by measuring the acoustic impedance of the bone. Impedance measurements were made at several locations within a bone cross-section at the level of the implant. Implants of various materials and surface treatments were used. It was observed, however, that the acoustic impedance...
Albumin, ethanol, and urea were measured in-vitro using Fourier transform infrared (FTIR) spectroscopy. The peak height and corresponding peak area of the spectra were computed for concentration prediction. This univariate method was compared with partial least squares (PLS) and principal component regression (PCR) multivariate routines. The standard errors of calibration obtained were cholesterol...
Clozaril, an antipsychotic agent, has several harmful side effects. An established computerized database was used to monitor Clozaril patients in New York State (NYS) Psychiatric Centers. Six centers with a total of 138 Clozaril patients were monitored from June to December 1991. White blood cell test results (WBC, % Gran (percentage of granulocytes), Hash Gran (absolute number of granulocytes)) were...
A procedure has been developed to determine the number of pulses and interpulse intervals necessary for an N-let (set of N closely spaced stimulation pulses) to elicit the maximal twitch response in human skeletal muscle. It was found that using a doublet (N=2) produced the largest force-time integral per pulse. Since muscular fatigue during electrical stimulation is believed to be a function of the...
In order to investigate neuronally derived algorithms for feedback and control, one joint of a conventional robotic arm was fitted with sensory and motor devices consistent with biological memory-motor models. In this system, a single potentiometer senses angular position of a given joint. From this signal, the forward and reverse velocity are derived, as are the acceleration and deceleration. Controlling...
A multidisciplinary rehabilitation engineering team has been formed at the University of New Hampshire. The role of the team is to work closely with the New Hampshire Department of Vocational Rehabilitation to develop cost-effective technological solutions that improve the productivity of identified clients. The authors provide an overview of the team's organization and the problem-solving approach...
Recent evidence has shown that there are two neural control processes involved in disparity vergence motor control: a fast component and a slow component. The fast component provides the major drive for the initial portion of the transient response (the first 300 ms of the movement) and appears to be open-loop. In the present work, the authors investigate the relationship between the fast component...
The authors derive a compartmental model for oxygen transport in vascular blood which is suitable for both steady and time-varying analysis, and which can be used with any kind of oxygen dissociation function. The derivation focuses on the establishment of expressions for the lumped convective term and the lumped oxygen dissociation function. Results of the simulation show that the value of the lumped...
The authors have used their positron emission tomography (PET) design algorithm to evaluate certain performance characteristics of the CTI-931 PET tomograph. The simulation model takes into account the characteristics of the source, the interplane collimators, the scintillation crystals, the photomultiplier tubes, and the coincidence detection schemes. The results of the simulation are compared with...
A circuit was developed to serve as an interface from an intact biological neuron to an electromechanical device. The circuit is a custom VLSI IC that contains a highly sensitive buffer, a neuron-like threshold discriminator, and a dedicated four-phase output driver. Nerve-like in behavior, the circuit detects action potentials from living nerve tissue, and if the activity exceeds a given threshold,...
An attempt was made to develop a small, expandable neural network that would oscillate when presented with an appropriate stimulus. The focus of the research is the modification and expansion of a single neuron simulation into a simulation of an interconnected multineuron oscillatory network. A single neuron model based on the work of Hodgkin-Huxley is used to develop a simulation of a generalized,...
The authors studied certain characteristics of the expectation-maximization (EM) algorithm for image reconstruction in positron emission tomography (PET). They have attempted to speed up the algorithm by performing some time-consuming computation only once, at the initiation stage. They have studied the resulting memory size, disk space, and CPU requirements versus the number of pixels in the reconstructed...
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