Abstract: Compositions and methods are provided for modulating the growth, development and repair of bone, cartilage or other connective tissue. Devices and stimulus waveforms are provided to differentially modulate the behavior of osteoblasts, chondrocytes and other connective tissue cells to promote proliferation, differentiation, matrix formation or mineralization for in vitro or in vivo applications. Continuous-mode and pulse-burst-mode stimulation of cells with charge-balanced signals may be used. Bone, cartilage and other connective tissue growth is stimulated in part by nitric oxide release through electrical stimulation and may be modulated through co-administration of NO donors and NO synthase inhibitors. Bone, cartilage and other connective tissue growth is stimulated in part by release of BMP-2 and BMP-7 in response to electrical stimulation to promote differentiation of cells.

Abstract: Compositions and methods are provided for modulating the growth, development and repair of bone, cartilage or other connective tissue. Devices and stimulus waveforms are provided to differentially modulate the behavior of osteoblasts, chondrocytes and other connective tissue cells to promote proliferation, differentiation, matrix formation or mineralization for in vitro or in vivo applications. Continuous-mode and pulse-burst-mode stimulation of cells with charge-balanced signals may be used. Bone, cartilage and other connective tissue growth is stimulated in part by nitric oxide release through electrical stimulation and may be modulated through co-administration of NO donors and NO synthase inhibitors. Bone, cartilage and other connective tissue growth is stimulated in part by release of BMP-2 and BMP-7 in response to electrical stimulation to promote differentiation of cells.

Abstract: A system and method for generating an electrical signal for use in biomedical applications may have power efficient features, support battery powered operation and, support a reduced risk of shock hazard. The system may include a controller for generating one or more control signals operable to control pulse generating and waveform processing circuits. The control signals may include at least two states alternating in a chosen pattern as a function of time. During at least one of the control signal states, an oscillator for generating a pulsed signal may be operable. During at least another of the control signal states, the oscillator can be disabled and completely shut off in order to conserve considerable power. The generated pulses may be processed to provide desired intensity and frequency components. The processed signals may be applied to biological material.

Abstract: A method and class of circuit configurations for coupling low-frequency signals from one stage of an electronic apparatus to another stage, from the outside world to such a stage, or from such a stage to the outside world, through the use of a plurality of symmetrical double-layer capacitors combined with other electronic components are disclosed. The capacitors are used for signal transmission while blocking direct current, rather than for energy storage. Use of double-layer capacitors in place of more conventional capacitors permits the transmission of a much wider range of signals with far less distortion. The technology is particularly well-adapted to use in medical devices, including bioelectronic stimulators, where redundant devices are required for safety in case of single component failure while unacceptable levels of distortion may occur when conventional components are used.

Abstract: An method and method for generating an electrical signal for use in biomedical applications, including two timing-interval generators, each optionally driving a multistep sequencer; analog, digital or hybrid means for combining the resulting timed signals into a complex electrical signal; optional filtering means for blocking direct current, removing selected frequency components from the resulting signal, and/or providing voltage step-up if needed; and conductive means for coupling the resulting signal to a human or animal body, food, beverage or other liquid, cell or tissue culture, or pharmaceutical material, in order to relieve pain, stimulate healing or growth, enhance the production of specific biochemicals, or devitalize selected types of organisms.

Abstract: An method and method for generating an electrical signal for use in biomedical applications, including two timing-interval generators, each optionally driving a multistep sequencer; analog, digital or hybrid means for combining the resulting timed signals into a complex electrical signal; optional filtering means for blocking direct current, removing selected frequency components from the resulting signal, and/or providing voltage step-up if needed; and conductive means for coupling the resulting signal to a human or animal body, food, beverage or other liquid, cell or tissue culture, or pharmaceutical material, in order to relieve pain, stimulate healing or growth, enhance the production of specific biochemicals, or devitalize selected types of organisms.

Abstract: An apparatus for generating an electrical signal for use in biomedical applications, including two timing blocks for generating timing intervals T1-T7, an interconnection block for combining these intervals into an output signal having predetermined relationships among the intervals, an output block for transmitting the output signal to a load, and, optionally, a filter for removing unwanted frequency components from the output signal and an adjustment block for selecting from among a plurality of output signals with predetermined characteristics. The output is a repeating succession of a burst of rectangular waves, an equalizing pulse (if needed) to cancel net DC, and a rest period of no signal.

Abstract: A voltage stabilizer apparatus with digitally-controlled emulation of servotransformer operation to provide smooth voltage control. Tap-switching on both the primary and the secondary sides of a transformer allows a small number of relays to provide a large number of voltage step-up and step-down ratios. The maximum number of achievable ratios is equal to Nmax=(m*n−p+1) where m is the number of primary taps, n the number of secondary taps, and p the number of taps which are common to both sets. The taps are preferably placed at approximately logarithmic intervals along the transformer winding to provide evenly-spaced step-up and step-down ratios. Additional components may include devices for sensing under- or over-voltages, preventing unwanted cycling under load, rectifiers, arc-suppression devices, circuitry for interfacing with the user's electronic equipment, and LEDs or other indicators for providing feedback on the operational state of the apparatus.

Abstract: A pulsed signal generator for biomedical applications, including electrical stimulation of fracture healing, treatment of osteoporosis, strengthening of freshly-healed bone after removal of a cast or other fixation device, and iontophoresis. The generator includes dual asymmetric oscillators and associated circuitry to deliver signals efficiently throughout the area to be treated. The components of the generator are selected so as to produce any desired output signal, including fixed and variable amplitude, fixed, variable, and swept frequency signals, and optional DC biasing. The pulse frequency and/or interval can be fixed or adjustable. In a preferred embodiment of the invention, the generator is powered by readily-available, inexpensive batteries.

Abstract: An apparatus and method for reducing cracking in a heated material as the material cools. The apparatus includes a variable frequency electric signal generator that is coupled to a transducer. The transducer produces a variable frequency acoustic signal in response to the variable frequency electric signal, which is applied to the heated material to reduce cracking as the material cools.

Abstract: A pulsed signal generator for biomedical applications, including electrical stimulation of fracture healing, treatment of osteoporosis, or to strengthen a freshly-healed bone after a cast or other fixation device has been removed. The generator includes dual asymmetric oscillators and associated circuitry to deliver signals efficiently throughout the area to be treated. The components can readily be selected so as to produce any desired output signal, including fixed-magnitude signals and (via suitable voltage-regulating devices) variable-magnitude signals. In addition, the pulse frequency and/or interval can be fixed or adjustable, as may be convenient. In a preferred embodiment of the invention, the generator is powered by readily-available, inexpensive batteries.

Abstract: An enclosure for isolating material from the ambient atmosphere yet allowing free access to the interior. The front wall of the enclosure includes a window portion and at least one opening with a frame assembly mounted therein. The frame assembly includes a first movable access frame and a first flexible curtain; at least one second movable access frame and a second flexible curtain are mounted in the first frame. The first frame is movable from side to side across the opening; the second frame is movable from side to side across the first frame, perpendicular to the direction of movement of the first frame. As the first and second frames are moved, the first and second curtains move also, such that the only opening through the front wall is through an access port in the second frame. By moving the first and second frames, the user has ready access to substantially all the interior of the enclosure, and can position the access port wherever convenient for the task at hand.

Abstract: An optical temperature measuring device utilizes thermochromic semiconductors which vary in color in response to changes in temperature. The thermochromic material is sealed in a glass matrix which allows the temperature sensor to detect high temperatures without breakdown. Cuprous oxide and cadmium sulfide are among the semiconductor materials which provide the best results. The changes in color may be detected visually using a sensor chip and an accompanying color card.

Abstract: A liquid level sensor based on a closed field circuit comprises a ring oscillator using a symmetrical array of plate units that creates a displacement current. The displacement current varies as a function of the proximity of a liquid to the plate units. The ring oscillator circuit produces an output signal with a frequency inversely proportional to the presence of a liquid. A continuous liquid level sensing device and a two point sensing device are both proposed sensing arrangements. A second set of plates may be located inside of the probe housing relative to the sensing plate units. The second set of plates prevent any interference between the sensing plate units.

Abstract: An optical temperature measuring device utilizes thermochromic semiconductors which vary in color in response to changes in temperature. The thermochromic material is sealed in a glass matrix which allows the temperature sensor to detect high temperatures without breakdown. Cuprous oxide and cadmium sulfide are among the semiconductor materials which provide the best results. The changes in color may be detected visually or by utilizing an optical fiber and an electrical sensing circuit.

Abstract: A reversible optical temperature indicator utilizes thermochromic semiconductors which vary in color in response to various temperature levels. The thermochromic material is enclosed in an enamel which provides protection and prevents breakdown at higher temperatures. Cadmium sulfide is the preferred semiconductor material. The indicator may be utilized as a sign or in a striped arrangement to clearly provide a warning to a user. The various color responses provide multiple levels of alarm.

Abstract: A package containing a tracer gas, and a method for determining the presence of a hole in the package by sensing the presence of the gas outside the package. The preferred tracer gas, especially for food packaging, is sulfur hexafluoride. A quantity of the gas is added to the package and the package is closed. The concentration of the gas in the atmosphere outside the package is measured and compared to a predetermined value of the concentration of the gas in the absence of the package. A measured concentration greater than the predetermined value indicates the presence of a hole in the package. Measuring may be done in a chamber having a lower pressure than that in the package.

Abstract: An apparatus for detecting the presence of a liquid in a region, including an electrically passive sensor adapted for contacting the liquid, and an electrically active detector. The sensor is a circuit with a pair of spaced-apart terminals connected to a switch that closes in the presence of the liquid. The detector carries an alternating current with a resonant frequency. When the sensor is placed in a region and liquid is present in the region, the circuit of the sensor is closed. By bringing the detector close to the sensor, an alternating current is induced in the sensor that will, in turn, alter the resonant frequency of the detector. The change in the resonant frequency is signaled by a transducer. The switch can operate by a change in conductivity of a material between the terminals of the sensor or by expansion of a liquid absorber that pushes the two terminals together, or by a change in the conductivity of the space between the terminals as a result of the presence of the liquid.

Abstract: An immersible solar heater comprising a light-absorbing panel attached to a frame for absorbing heat energy from the light and transferring the absorbed heat energy directly to the fluid in which the heater is immersed. The heater can be used to heat a swimming pool, for example, and is held in position and at a preselected angle by a system of floats, weights and tethers so that the panel can operate efficiently. A skid can be used in one embodiment to prevent lateral movement of the heater along the bottom of the pool. Alternative embodiments include different arrangements of the weights, floats and tethers and methods for making the heater.

Abstract: A device for detecting switch closure such as in a keypad for entering data comprising a matrix of conductor pairs and switches, each pair of conductors shorted by the pressing of a particular switch, and current-regulating devices on each conductor for limiting current in one direction and passing it without limit in the other direction. The device is driven by alternating current. The ends of the conductors in a conductor pair limit current of opposing polarities with respect to each other so that the signal on a shorted pair is an alternating current signal with a unique combination of a positive and a negative peak, which, when analyzed, allows the determination of which key was pressed. The binary identification of the pressed key is passed to the input port of a host device.