By Topic

Proceedings of the 1991 IEEE Seventeenth Annual Northeast Bioengineering Conference

4-5 April 1991

Filter Results

Displaying Results 1 - 25 of 112
  • Establishing constitutive relationships for soft biological tissues

    Publication Year: 1991
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (58 KB)

    Summary form only given. An algorithm is presented by which stress-strain relationships, or constitutive equations, for various soft tissues may be developed, and some of the pitfalls affecting the process are discussed. These concepts are illustrated using the lung as an example. Four elements are required for analysis of the deformation of a body: (1) the geometry of the body in question, (2) a ... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Detection of EEG transients by changes in dimensional complexity

    Publication Year: 1991
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (31 KB)

    Summary form only given. A simple box accounting algorithm is applied to measure the fractal dimension of electroencephalography (EEG). Artificial transients of varying EEG characteristics are embedded. The change is noted in the fractal dimension within a window that is passed along the entire time series. Three embedded evoked potential spikes 100 ms apart buried anywhere in the time series are ... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Evaluating the validity of the Oxylog in adults at rest and during exercise

    Publication Year: 1991, Page(s):147 - 148
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (163 KB)

    The reliability of a portable oxygen consumption meter (Oxylog) before its clinical utilization is determined by comparing simultaneously collected data from an Oxylog and a Medical Graphics 2001 metabolic cart during rest and bicycle ergometer exercise in normal adults. The results indicate differences in oxygen consumption and inspiratory ventilation values between the two systems. It is propose... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Proceedings of the 1991 IEEE Seventeenth Annual Northeast Bioengineering Conference (Cat. No.91CH2997-5)

    Publication Year: 1991
    Request permission for commercial reuse | PDF file iconPDF (12 KB)
    Freely Available from IEEE
  • Two and three-dimensional motion models for the left-ventricular wall

    Publication Year: 1991, Page(s):193 - 194
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (144 KB)

    The authors present a unified framework for visual motion tracking of nonrigid objects with specific applications to the left ventricular endocardial wall motion. The theory is based on differential geometry and considers both two-dimensional contours and three-dimensional surfaces and in each case uses an elastic model of the object with constraints on the types of motion allowed for tracking the... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Impedance mapping of myocardial tissue during ischemia

    Publication Year: 1991, Page(s):189 - 190
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (132 KB)

    An impedance measurement system was developed for measuring myocardial tissue impedance (MTI) during ischemia in sheep and epicardial mapping system was developed that used a four electrode method with cardiac cycle gated and signal averaged measurements. After 60 minutes of ischemia, MTI increased by an average of 200% compared to non-ischemic tissue. A myocardial tissue model was developed which... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Pulmonary input impedance spectra in models of chronically altered pulmonary hemodynamics

    Publication Year: 1991, Page(s):187 - 188
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (128 KB)

    Pulmonary input impedance spectra were estimated in one-month-old lambs whose circulation had been altered during the first few days of life to mimic the pulmonary. hemodynamic states observed in infants and children with left-to-right shunts (high flow) and /or pulmonary vascular obstructive disease (high pressure). Spectral results obtained from the animal models were compared with those obtaine... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Modeling microvascular networks

    Publication Year: 1991, Page(s):185 - 186
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (144 KB)

    The authors describe preliminary results from a 55-branch distributed model of a microvascular network. Linearized equations of motion and continuity for each branch were solved simultaneously to generate the input impedance of the model. Effects of dimensional (length, radii) and structural variations of the network were investigated. The input impedance is insensitive to physiologically reasonab... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Effects of heat and pressure on surface light reflectance at 660 and 880 nm

    Publication Year: 1991, Page(s):137 - 138
    Cited by:  Papers (1)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (136 KB)

    Presented is an analysis of changes in reflectance at the tissue surface resulting from heat-induced hyperemia and from applied pressure at the skin surface. Optical reflectance measurements are at wavelengths of 660 nm (red) and 880 nm (infrared). Human subject data consist of in vivo measurements from the calf of the leg. An index is calculated which is a logarithm of the ratio of reflected ligh... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Performance optimization of the pulsatile synchronous LVAD based on myocardial energetics and cardiac output using a computer simulation

    Publication Year: 1991, Page(s):183 - 184
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (156 KB)

    When myocardial infarction compromises cardiac output, treatment sometimes involves the application of a pulsatile synchronous left ventricular assist device (LVAD). The authors use a computer simulation to explore the possibility of optimal phasing of pump cycle with respect to events in the cardiac cycle from the standpoint of improved myocardial energetics and system flow. Central to the simula... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Effects of chronic stress on startle response: a three dimensional analysis

    Publication Year: 1991, Page(s):135 - 136
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (148 KB)

    A startle measuring system was designed to isolate forces exerted by a rodent into three rectangular coordinates, digitize and store the resulting signals, and process the signals to perform correlation and spectral analysis on them. This effect is studied to find characteristic differences in behavior between normal and chronically stressed animals. This system is claimed to be an improvement on ... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Modeling neurite outgrowth on laminin in vitro

    Publication Year: 1991, Page(s):163 - 164
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (92 KB)

    Experimental parameters were measured and incorporated into a mathematical model to describe axonal outgrowth on the extracellular matrix molecule, laminin, in vitro. To elucidate the role of laminin and other basement membrane components in axonal growth and guidance, a systematic analysis of the effects of these various molecules on outgrowth characteristics such as the rate and direction of gro... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Phase plane analysis of post extra-systolic potentiation

    Publication Year: 1991, Page(s):181 - 182
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (132 KB)

    Improved cardiac function after a spontaneous extrasystole in an anesthetized mongrel dog preparation was analyzed based on left ventricular pressure measurement only. Experiments were performed on open-chest anesthetized dogs. Left ventricular pressure (LVP) was measured with a Millar type catheter-tip pressure transducer inserted through an isolated femoral artery and advanced to the left ventri... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A method for monitoring finger and palm pressure during perception threshold testing of compression neuropathies

    Publication Year: 1991, Page(s):133 - 134
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (200 KB)

    Small changes in finger and palm pressure were detected and recorded with force sensing resistor (FSR) circuitry. This was accomplished once an optimum value of sensitivity adjustment was determined. It was found that a value of approximately 100 kΩ for the sensitivity resistor allowed minimal force (less than 100 g) to cause appreciable change in the output of the sensor's amplifier circuit... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • An alternative mobility aid for the blind: the `ultrasonic cane'

    Publication Year: 1991, Page(s):158 - 159
    Cited by:  Papers (3)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (192 KB)

    A design of a small portable electronic cane utilizing Polaroid's Ultrasonic Ranging Unit intended to supplement or replace the traditional long cane is presented. A prototype was fitted in a flashlight-like enclosure made of a PVC tube with an external battery pack as power supply and an ear-plug, for the audible output. Preliminary testing of the prototype with two blind individuals shows that s... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Use of ventilator driven forced oscillations for characterizing human respiratory mechanics at low frequencies

    Publication Year: 1991, Page(s):73 - 74
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (156 KB)

    Frequency domain and offline and online time domain techniques are compared to estimate respiratory mechanical properties using standard ventilator waveforms at low frequencies. Both methods are shown to yield consistent parameter estimates for a simple series RC model and pure sine wave input. However, they could not accurately predict frequency dependence of respiratory resistance from 0 to 1 Hz... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Modeling of hypertension-induced left ventricular hypertrophy

    Publication Year: 1991, Page(s):179 - 180
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (232 KB)

    A theoretical model of the left ventricle capable of predicting shape and size in relation to the loading and metabolic conditions is presented and applied to the study of hypertension-induced hypertrophy (HIH). Oxygen consumption per gram tissue is imposed as the control parameter. HIH is produced by progressively increasing mean aortic pressure (MAP) on the normo-tensive model. The focus is on t... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A single artery model with stenosis in the time domain

    Publication Year: 1991, Page(s):87 - 88
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (128 KB)

    A time domain model of pressure pulse propagation in a single artery with stenosis is presented. The aortic pressure pulse is used as input with a single axisymmetric stenosis of varying parameters simulated at 15 cm from the heart in the 30-cm segment of aorta modeled. Results are presented for stenosis length and percent constriction variation for two stenosis shapes (cylindrical and triangular)... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Analysis of parameters for optimization of biological tissue impedance contrast

    Publication Year: 1991, Page(s):131 - 132
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (176 KB)

    A system for determining the instantaneous position of a multielectrode intraventricular catheter, based on the principles of impedance plethysmography, is developed. In order to identify the conditions producing the highest impedance contrast (tissue to blood resistivity ratio), current density and frequency of the source, as well as the effects of the biological interfaces, are examined. Experim... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A measurement technique to monitor pelvic tilt

    Publication Year: 1991, Page(s):156 - 157
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (192 KB)

    In order to verify that the tilt gage tracks the motion of the pelvis, a study was performed to compare pelvic motion, in this case rotation, measured by the pelvic motion device (PMD) with the motion measured by the tilt gage alone. Seven subjects (five men, two women) were tested. A regression model was used to assess the degree of accuracy in predicting the actual PMD angle from the voltage on ... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Modelling O2 and CO2 dissociation curves of newborn infants

    Publication Year: 1991, Page(s):71 - 72
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (160 KB)

    In order to study gas exchange and respiratory control system stability in the newborn period, a model of the O2 and CO2 dissociation curves is developed which incorporates the changes in hemoglobin with age. The model is a modification of Grodin's equations. The dissociation curves generated by the computer model take into account hematocrit, bicarbonate concentration, pH, b... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Preliminary results of IR spectroscopic characterization of cholesterol

    Publication Year: 1991, Page(s):175 - 176
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (228 KB)

    The authors propose the use of skin over the bony prominences of the hands as a site for infrared (IR) exposure to measure blood cholesterol. Cholesterol, when exposed to IR radiation, generates an absorption spectrum Characteristic of its molecular composition. Aqueous solution of bovine cholesterol, (Sigma Chemicals) with 100mg% and 200mg% of concentration was exposed to laser using attenuated t... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Oscillatory flow distribution at a bifurcation

    Publication Year: 1991, Page(s):85 - 86
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (128 KB)

    Flow-distribution in a 90° bifurcated airway during high-frequency oscillation is analyzed by numerical simulation. The parent and two daughter branches are of equal length and diameter, describing a T-junction rotated by 90°. The flow is considered laminar and incompressible, which is reasonable for small tidal volumes. The solution has been limited to two-dimensional channels, merely by ... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Use of a discrete electro-oculographic control system with and without oscillatory motion of the head

    Publication Year: 1991, Page(s):129 - 130
    Cited by:  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (148 KB)

    The effectiveness of the discrete electrooculographic control system (DECS) and various methods of its use are studied. This device utilizes the dipole present in the eye to emulate a standard computer input device. Initial tests of the DECS system parameters show that this device may be useful as an input device for persons with some degree of uncontrollable vibration when resting or moving. Thou... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A comparative study of rowing biomechanics

    Publication Year: 1991, Page(s):271 - 272
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (176 KB)

    The author describes an instrumentation package that has been developed to collect data for the study of rowing biomechanics. Currently, this system is interfaced with a Concept II rowing ergometer. The system acquires and analyzes handle and footstretcher kinetics as well as handle, limb segment and seat kinetics. Given these measurements, a biomechanical model of ergometer rowing can be develope... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.