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Biomedical Engineering, IEEE Transactions on

Issue 3 • Date May 1977

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Displaying Results 1 - 18 of 18
  • Interactive Computer Modeling of the Musculoskeletal System

    Publication Year: 1977 , Page(s): 213 - 219
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3484 KB)  

    The complexity of many biomechanical systems, such as the human body musculoskeletal structure, can render their modeling and analysis a painstaking task. The incorporation of interactive computing and graphical display techniques into a computerized analysis system facilitates the reformulation of existing models of the human musculo-skeletal structure so they can be used to investigate many different conditions and complex dynamic activities. The system can also be used to easily extend the modeling technique to the investigation of the muscle load sharing of other vertebrates. The graphics capability of the system can be invaluable for visually checking the adequacy of the constructed models. For example, lines of action representing muscles which wrap on skeletal bones can be conveniently incorporated into the analysis. The developed system would allow users in many research and application activities to perform analysis of the musculoskeletal structure without extensive training in engineering analysis methods. View full abstract»

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  • Optimum Modeling of Vascular Beds Using Indicator-Dilution Measurements

    Publication Year: 1977 , Page(s): 219 - 226
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1112 KB)  

    This paper considers the model of a vascular bed as H(s) with possibly an infinite number of poles. It then solves the problem of identifying a suitable low order approximation to it. The optimal model order and parameter estimates are found based on the critereon similar to that developed by Akaike [5]. This method prevents a direct deconvolution. Deconvolution is known to be sensitive to errors. View full abstract»

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  • Silicon Force Transducer for Extraluminal Measurement of Oviduct Contractile Activity

    Publication Year: 1977 , Page(s): 226 - 231
    Cited by:  Papers (2)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2328 KB)  

    A miniature, implantable force transducer has been developed for the extraluminal measurement of segmental smooth muscle contractility and has been applied to the oviduct in the Macaca mulatta. The force transducer makes use of a commercially available piezoresistive silicon strain sensor bonded to a flexible metal strip. The device is housed in a tissue compatible, gas sterilizable tubule upon which are placed sutures for subsequent extraluminal attachment to an organ. View full abstract»

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  • Measurements of Signal Components in Single Visualy Evoked Brain Potentials

    Publication Year: 1977 , Page(s): 232 - 241
    Cited by:  Papers (44)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (6244 KB)  

    A two step procedure is described for measuring the characteristics of visual evoked brain potentials. First, the recorded waveforms are processed by a filter designed to minimize the mean square error produced by the ongoing EEG. This filter is different for each subject and is based on certain statistical properties of the measured data. Second, the filtered potentials are searched automatically by a computer to determine the existence and location of the individual components in the responses. By aligning the corresponding components in different waveforms and averaging over the waveform segment in the immediate vicinity of the peak, a latency corrected average is obtained that provides a new representation of the response waveform. View full abstract»

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  • Studies of the Electrocardiogram Using Realistic Cardiac and Torso Models

    Publication Year: 1977 , Page(s): 242 - 252
    Cited by:  Papers (28)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1917 KB)  

    Several aspects of the forward and inverse problems of electrocardiography are investigated through the use of digital computer models. Two forms of a fixed location, variable moment, 20-dipole cardiac model of QRS are developed from actual cardiac excitation data. One form uses time-varying orientation dipoles; the other uses fixed orientation dipoles. An electric multipole expansion (EME) cardiac model employing the dipole, quadrupole, and octupole terms is also developed and used as an equivalent forward and inverse cardiac model. Two realistically shaped torso models are used. The homogeneous torso has uniform conductivity; the inhomogeneous torso contains realistically shaped lung regions with reduced conductivity. It is found that when the EME model is used as an equivalent forward cardiac model, it can accurately represent the actual 20-dipole cardiac model in the homogeneous torso. Limb leads are accurately represented by the dipole terms alone while the precordial leads require the quadrupole and octupole terms. It is also found that while the lung regions have little effect on the ECG's produced by the models, these regions can have a significant effect on the inverse solutions for certain dipoles in the 20-dipole cardiac model. These lung regions appear to have a much smaller effect on the dipole terms in the EME model. Solutions of the inverse problem for the terms in the EME model indicate that when a limited number of measurements are used, the best results can be obtained by uniform distribution of the measurements over the torso. View full abstract»

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  • Embedded Bare and Insulated Antennas

    Publication Year: 1977 , Page(s): 253 - 260
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1413 KB)  

    A quantitative study is made of the receiving qualities of antennas embedded a short distance below the surface of a dissipative material in terms of the complex transfer function and the properties of the antenna. Types of antennas investigated include bare and insulated dipoles as single elements and in two-element broadside arrays. The eccentrically insulated dipole is also studied. Actual voltages across practical load impedances are determined when the antennas are embedded specifically at depths of 0.1, 0.5, and 1.0 cm in hide or skin. Comparable results apply also to muscle. A similar but more involved analysis is required if quantitative account is to be taken of a subcutaneous layer of fat between the skin and muscle. It is shown that the frequency for maximum voltage across the load with skin as the material is 700 MHz and that resonant bare dipoles have a practical length. However, the higher directivity of insulated dipoles provides comparable voltages with the same antennas and loads at 3 GHz. View full abstract»

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  • Linear AC Electrode Polarization Impedance at Smooth Noble Metal Interfaces

    Publication Year: 1977 , Page(s): 260 - 268
    Cited by:  Papers (7)  |  Patents (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1479 KB)  

    The linear A. C. electrode polarization impedance of polished platinum has been analyzed on the basis of the rate determining mechanism of the oxygen electrode. The impedance has been found to follow the frequency dependence predicted by an adsorption of the electroactive species. The effects of D. C. potential and specific adsorption of anions have been studied and their effect on the electrode polarization impedance is in agreement with the adsorption mechanism. View full abstract»

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  • Pressure and Velocity Fluctuations Associated with the Flow Through a Stenosis with Upstream Roughness

    Publication Year: 1977 , Page(s): 269 - 277
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1709 KB)  

    The nature of steady flow of a blood-analog fluid distal to a stenosis was demonstrated in a model artery. The relationship was explored between such flow and the generation of velocity and pressure fluctuations that might lead to the production of sound in an artificially roughened, rigid tube. Attention was directed solely to the generation of pressure fluctuations within the fluid itself. No regard was paid to the possibility of structural vibration or resonance as a response to fluctuations generated in the fluid other than to eliminate the possibility for such effects in the model and test stand. View full abstract»

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  • Analysis of a Network of Electrically Coupled Neurons Producing Rhythmic Activity in the Snail Helisoma Trivolvis

    Publication Year: 1977 , Page(s): 277 - 287
    Cited by:  Papers (11)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2207 KB)  

    This paper deals with a quantitative analysis of a network of electrically coupled neurons (cyberchrons) in the snail Helisoma trivolvis. This network produces regular bursts of activity which drive the motoneurons controlling the feeding musculature. Analysis of the time constants and Bode plots obtained from current injection leads to the development of an equivalent model circuit describing the functional relationships of the individual neuronal elements. The equivalent model is used to demonstrate compensation of the frequency response of an individual neuron by the effective loading of the rest of the network. However, the current observed in a postsynaptic neuron is intergrated across the long cell time constant resulting in increased temporal and spatial summation. This frequency compensation and long duration of the postsynaptic response are both believed to be instrumental in the maintenance of a high frequency burst. This model will act as a framework on which active properties such as burst form, timing, and termination can be tested. View full abstract»

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  • Non-Linear Boundaries for Differentiation Between Epileptic Transients and Background Activities in EEG

    Publication Year: 1977 , Page(s): 288 - 290
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (540 KB)  

    The epileptic transients and background activities of EEG from ten patients are found to group in two separate clusters in a two-dimensional sample space according to their half-wave amplitudes and durations. Assuming that the two clusters are from jointly Gaussian distributions with equal a priori probabilities, an optimum decision boundary is determined for each patient. An estimated decision boundary is also obtained for each patient based only on the information of the individual's background cluster. The results indicate that the performance of such an estimated boundary is good in comparison with the optimum decision boundary. View full abstract»

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  • A Temperature Control System for Small Biological Preparations, Displaying Relatively Fast Heating and Cooling Capability

    Publication Year: 1977 , Page(s): 291 - 293
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (573 KB)  

    An apparatus is described with which it is possible to warm and cool the main duct of rabbit submaxillary gland in 10cc Ringer solution between 0°C and 50°C. The apparatus can be used for any small biological preparations such as muscles, nerves, etc. The heating and cooling is performed by a peltier element together with its control unit. Temperature is measured with a Cu-Const. thermocouple-with the reference placed in melting ice. The absolute accuracy of the temperature is ±0.5°C but reproducibility is within 0.10C. Speed of warming up for a large temperature change (AT) is 0.8°C/s. Cooling is-stower, i.e., 0.4°C/s. For AT 5°C the speed of warming up is about 0.60°C/s and the cooling rate in this case varies between 0.5°C/s and 0.16°C/s depending upon starting temperature. Full details are given about the construction of the control unit and the perfusion chamber in which the main duct is mounted. Some modifications are discussed with which it is also possible to use the system for flat biological preparations. The use of the apparatus as a programmable temperature system or as a temperature function generator is also discussed. View full abstract»

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  • A Head-Mounted 24-Channel Evoked Potential Preamplifier Employing Low-Noise Operational Amplifiers

    Publication Year: 1977 , Page(s): 293 - 297
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2036 KB)  

    A simple circuit employing operational amplifiers yields an inexpensive low-noise biological amplifier. Design parameters are discussed and performance measured. When twenty-four of these amplifiers were incorporated in a head-mounted evoked potential preamplifier, noise increased while common mode rejection and stability decreased. These effects are explained and successfully controlled by minimizing source resistance and adding a simple feedback circuit. View full abstract»

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  • Indirect Determination of Microelectrode Geometry

    Publication Year: 1977 , Page(s): 297 - 300
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1913 KB)  

    Measurement of the electrical properties of living cell membranes often involves electrolyte filled glass capillary microelectrodes, the properties of which enter into the interpretation of the measurements. Since the tips of the electrodes are beyond the resolving power of the light microscope, we present here indirect methods for the determination of the tip geometry based on resistance measurements. A model consisting of a 2-parameter family of geometric shapes is selected to agree with observed resistances over a range of hydrostatic pressure heads and fluid conductivities. For a specific electrode the two defining parameters are evaluated from the resistances of the electrode when immersed successively in pools of two different conductivities. View full abstract»

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  • Indirect Measurement of Intracellular Conductivity

    Publication Year: 1977 , Page(s): 300 - 302
    Cited by:  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (625 KB)  

    The apparent resistance of a fluid-filled micropipette depends upon the conductivity of the fluid in which its tip-is immersed. When the electrode is involved in the determination of the impedance of cell membranes, then the intracellular conductivity must be known. Techniques used in large cells require extrusion of intracellular fluid or the simultaneous insertion of two or more electrodes in a single cell, and are not feasible for small cardiac cells. We present an indirect method in which. two unlike electrodes are inserted individually into distinct cells of a given type. The difference in measured resistances is independent of the membrane impedance, and can be calibrated by immersion in a sequence of fluids of known conductivities. View full abstract»

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  • Comments on "Modeling the Stationarity and Gaussianity of Spontaneous Electroencephalographic Activity"

    Publication Year: 1977 , Page(s): 302
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (194 KB)  

    It is pointed out that the Kolmogorov-Smirnov tests in the above paper1 are performed with a high correlation between adjacent samples. The consequence is results which are misleading. View full abstract»

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  • Contributors

    Publication Year: 1977 , Page(s): 303 - 305
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    Freely Available from IEEE
  • A Cordial Invitation to Apply for IEEE Membership ...

    Publication Year: 1977 , Page(s): 305-a - 305-b
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    Freely Available from IEEE
  • Blank Page

    Publication Year: 1977 , Page(s): 305c
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    Freely Available from IEEE

Aims & Scope

IEEE Transactions on Biomedical Engineering contains basic and applied papers dealing with biomedical engineering. Papers range from engineering development in methods and techniques with biomedical applications to experimental and clinical investigations with engineering contributions.

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Bin He
Department of Biomedical Engineering