Abstract: A tissue hyperthermia system and method improves temperature monitoring and control along an energy emitter such as an RF electrode. A two-phase heat transfer system includes a material within an enclosed vessel that is thermally coupled to the electrode. Energizing the electrode to an operating condition emits energy into tissue and heats at least to a threshold temperature wherein the material undergoes a phase transformation within the vessel between a liquid phase and a vapor phase. The phase change assists in cooling, monitoring, and control of emitter temperature. Algorithms estimate maximum temperature either at the emitter or in tissue adjacent the emitter based on monitored parameters at the vessel. Multivariate algorithms use simultaneous power and temperature readings to estimate actual regional temperature, including electrode or tissue hot-spot temperature. A multivariate algorithm is based in particular upon time-dependent aspects of a pulsed RF operating mode.

Abstract: An active drive is used to improve the response time of any vibrotactile transducer. A closed loop implementation of such a drive monitors the vibrotactile stimulus and by comparing it with an input signal generates an error signal driving the transducer. In an open loop active drive implementation, an input signal is shaped into a driving signal of a form designed to produce a desired vibrotactile response. The tactile interface adapts flat vibromotor transducers used as a silent alarm in cell phones for vibrotactile application. The adaptation involves means of fastening vibromotors to the skin implemented by adhesive tape, adjustable elastic band or specialized glove.

Abstract: A roto-oscillator and a velocity-sensing driver producing vibrotactile skin stimulation are disclosed. Driver current flowing through a coil produces a magnetic field that interacts with a roto-oscillating permanent magnet. Shaft supported and shaft-less embodiments are disclosed. Spring linkages are used to constrain the unenergized angular position of the roto-oscillating permanent magnet with respect to the coil current-induced magnetic field, such as to substantially optimize a vibratory torque generation. Spring linkages further serve to store the kinetic energy of roto-oscillation and to determine the optimum frequency of oscillation and the direction of vibrotactile stimulus. A velocity sensing circuit is used to provide a feedback signal for the roto-oscillator driver.

Abstract: A cardiac ablation apparatus including a solenoidal antenna, monitoring electrodes, and a coupling network at a distal end of a catheter transmission line, and another coupling network at the proximal end of the catheter transmission line to connect the catheter to the source of radiofrequency (RF) power and to an intracardiac electrogram monitor. Solenoidal antenna design includes single and multiple windings with varying geometrical features. Plated plastic tri-axial design of a transmission line offers unitary fabrication. A catheter with variable impedance electrode and gap coatings has features useful for both ablation and for hyperthermia applications.

Abstract: The Active Sound Absorber of the invention is based on an electroacoustical transceiver defined as a bilateral electroacoustical transducer acting as both a diaphragm actuator and motion sensor, and an associated mutual inductance discriminator, in a electroacoustical positive feedback system. Selected embodiment of such a system is an unvented hearing aid where the Active Sound Absorber combats the occlusion effect.

Abstract: The invention provides a thermal design of a catheter where the active electrode is partially covered by a heat conducting and electrically insulating heat-sink layer for localizing and controlling an electrical heating of tissue and cooling of the active electrode by convective blood flow. The invention further comprises a current equalizing coating for gradual transition of electrical properties at a boundary of a metallic active electrode and an insulating catheter tube. The current equalizing coating controls current density and the distribution of tissue heating.

Abstract: Liquid metal gallium-filled balloon catheter is connected to a source of heating power. An improved method of hyperthermia and ablation is made possible by ease of insertion and conformity to complex intracavitary geometry by liquid metal. Closeness of gallium melting point to body temperature makes insertion of solid gallium possible and subsequent melting after insertion. Method of balloon ablation of endometrium is described.

Abstract: A cardiac ablation apparatus including a solenoidal antenna, monitoring electrodes, and a coupling network at a distal end of a catheter transmission line, and another coupling network at the proximal end of the catheter transmission line to connect the catheter to the source of radiofrequency (RF) power and to an intracardiac electrogram monitor. Solenoidal antenna design includes single and multiple windings with varying geometrical features. Plated plastic tri-axial design of a transmission line offers unitary fabrication. A catheter with variable impedance electrode and gap coatings has features useful for both ablation and for hyperthermia applications.

Abstract: The invention provides a thermal design of a catheter where the active electrode is partially covered by a heat conducting and electrically insulating heat-sink layer for localizing and controlling an electrical heating of tissue and cooling of the active electrode by convective blood flow. The invention further comprises a current equalizing coating for gradual transition of electrical properties at a boundary of a metallic active electrode and an insulating catheter tube. The current equalizing coating controls current density and the distribution of tissue heating.

Abstract: The invention provides an intracavitary ultrasonic scanner with a helical scan. Mechanical and electronic steerable array implementations of the helical scan are described. A plastic cover sheath, filled with coupling fluid, covers the probe of the scanner. Portions of probe are porous allowing the coupling fluid to penetrate to the outside of the sheath. An improved polar coordinate decoding system provides an accurate control of the scan and allows storage of scan information in voxel memory.

Abstract: Improvement in active noise reduction based on a negative feedback electro-acoustical system which consists of an Electronic Earplug seated in the concha fossa combining active and passive noise reduction in the quiet zone at the ear, a bilateral transducer circuit which drives a speaker as an acoustical velocity source, a shunt feedback control filter network which improves stability and increases noise reduction, and a combined input noise-filter/feedback system. A typical application is in a noisy environment for hearing protection and for improved communication capability, e.g., in vehicular communication, telephone, intercom, hearing aids, and stethoscopes.

Abstract: Radiofrequency (RF) heating applicator, located at the distal end of a coaxial line catheter, produces deeper and more uniform heat dissipation. The active applicator element is a conductor helix fed via the coaxial line. The applicator has provisions for interception of intracardiac electrogram signal. A cardiac ablation system using the above catheter, ablates cardiac tissue responsible for ventricular tachycardia. The ablation system provides means to monitor intracardiac electrograms and to control the RF power. A variation of the helical applicator can be used in a hyperthermia system for treatment of malignant tumors.

Abstract: Piezopolymer actuator, wound in a bifilar fashion on two pins, is operated in a compressive mode without buckling. In addition to constraining motion of the winding along the surface of the pins, the pins also provide wide area electrical contacts with conductive electrodes on the surfaces of the piezopolymer strip. The electrodes consist of a thin film of metallization coated with graphite. Graphite coating heals microcracks in metallization, adds body to the piezopolymer strip, and lubricates winding-pin interfaces. Modular linear arrays of actuators are readily built from a single strip of piezopolymer. Linear array modules are in turn clamped together to form a two-dimensional array. Typical application is a tactile array for the blind.

Abstract: The invention provides for an inexpensive plotter/digitizer which can be attached to existing drafting boards of varying sizes. The device uses flexible links, such as cables. Length, speed, and tension of the links is monitored by sensors. The speed, accuracy, and line quality of plotting are improved by reduction of the weight of moving components and mechanical simplification of the drive mechanism. Trajectory Control for more than two link drives for prescribed two-dimensional motion is described together with Stationary Control which maintains required tension on cables. Microprocessor controlled, multimode operation of individual drives is indicated.

Abstract: Digitizer incorporates two novel position encoders. One position encoder comprises means for periodic spatial calibration against an accurate pattern of reference marks, thereby improving accuracy to the limit of resolution. Optionally, it also includes temperature and humidity compensation. Superior accuracy is achieved without tight tolerance requirements for mechanical components. The same technique can be used for error detection in digital motion control.The other position encoder, used primarily for menu data entry, is based on a discrete resistor array, combined with pulse position modulation of array columns. Its main advantage is simplicity and low cost.The digitizer is ergonomically designed, so that the operator can digitize coordinates with the left hand while inputing from the menu with the right hand.

Abstract: A method and apparatus is provided for determining the presence or absence of a coating on a substrate. The substrate is placed into optical contact with a light guide and the principle of frustrated total internal reflection is utilized. Light scattered from the coating surface is monitored to indicate the presence of a coating and failure to detect scattered light indicates the absence of said coating.

Abstract: This invention relates to a thermometer and more particularly to a fast response clinical thermometer. The active element is in the form of a thin sleeve which is in direct contact with the body tissue or other item to be measured. The large ratio of surface to volume of the active element permits it to reach temperature equilibrium rapidly. Temperature dependent changes in the sleeve material influence a coil which is inductively coupled to the sleeve. The coil in turn controls an oscillator frequency which can be converted to a digital display of the measured temperature.

Abstract: A replica bridge sensing circuit, comprising an amplifier having inverting and non-inverting inputs, which are symmetrically connected to a generator through a bridge circuit that has replica elements in corresponding branches. Replica elements are defined as circuit components which because of identity of the manufacturing process, are nearly identical both physically and electrically. A nearly balanced replica bridge, so connected, between the input and the output of such an amplifier forms a Replica Bridge Oscillator (RBO) circuit. Non-linear elements are included in the oscillator circuit to stabilize the amplifier output amplitude and the phase angles between the inputs and output. Replica Bridge Oscillator operation is substantially immune to changes in environmental conditions and to changes in the power supply voltages.

Abstract: A method is disclosed for maintaining continuity in a manufacturing process employing one or more webs provided in the form of shorter raw material webs in which the raw material webs are spliced together end-to-end as the preceeding web of the same material is depleted, and those web portions containing splice material are detected at a later stage of the process by a microwave detector. A microwave detector is provided in the form of a slotted microwave cavity through which the web may be continuously passed to detect the splicing tape in the web.