Abstract: Biologically active compounds are classified according to their effect on ion channels, changes in membrane potential and ionic currents, and the frequency content of action potentials that the compound(s) evoke in excitable cells. The spectral density changes of such evoked membrane potential or action potential are a characteristic for each channel type that is modulated by the test compound. A pattern of spectral changes in membrane potential is determined by contacting a responsive cell with a compound, and monitoring the membrane potential or ionic currents over time. These changes correlate with the effect of that compound, or class of compounds, on the ion channels of the responding cell. This pattern of spectral changes provides a unique signature for the compound, and provides a useful method for characterization of channel modulating agents.

Abstract: A conductance sensor uses a high impedance feedback oscillator to drive a single coil at the natural resonant frequency of the coil coupled to a measured material. The amplitude of the driving signal is also feedback controlled. The error signal of the amplitude control yields a measurement of resistance of the measured material. The combination of frequency adjustment and amplitude control eliminates non-resistance impedance effects and amplitude-dependent effects allowing high precision, high sensitivity measurement.

Abstract: Apparatus and method for determining a mechanical property of an organ or a body part. The method includes positioning an impedance sensor within a blood vessel. The impedance sensor has at least two electrodes disposed within the blood vessel, which is mechanically coupled to the organ or body part. The method further includes determining the electrical impedance between the two electrodes to obtain an impedance signal correlated with the mechanical property of the organ or body part. The organ may be the heart, lungs, uterus, urinary bladder, part of the gastrointestinal tract and the brain. The impedance sensor includes at least two spaced apart electrodes capable of being disposed within a blood vessel. The sensor is operatively connected to an impedance determining unit which determines the impedance between the electrodes. The impedance sensor may be a part of an insertable or implantable lead or catheter like device.

Abstract: Rapid determination of pathogen and neoplasm levels is associated with irradiation in the processing of meat in order to assure quality with regard to both desired pathogen levels and integrity of the meat minimizing the level of irradiation utilized. Rapid determination of pathogen and neoplasm level by sensitive measurement of the rate of change of electrical impedance through a sample tested in a conductivity cell is suggested. Use of ultrasonic aqueous bath of sufficient energy level to cause cavitation impingement of the exterior surfaces of the meat so immersed is also suggested. The use of ultrasound achieves accelerated natural depuration by stimulating the natural excretory processes of living shellfish and achieves microscopic cleansing of the exterior of shellfish alive or dead. Said irradiated sample is analyzed for metabolic activity of foodborne contaminants and displayed as a two or three dimensional model.

Abstract: A two-dimensional sensor is described including a substrate having a Si layer, a SiO2 layer and a Si3N4 layer. On the surface of the Si back side, a thin film is formed by vapor deposition for making an effect electrode. On the surface of the Si3N4 front side, a fence is attached for containing a sample cell, culture medium and a reference electrode. This sensor is placed in an incubator and a bias voltage is applied between the effect and reference electrodes. When a high frequency modulated laser beam irradiates a spot on the back side of the sensor substrate, a signal of AC photocurrent is obtained from the effect electrode. This signal corresponds to a potential alteration due to the cell activity substantially at the spot. The signal is processed in a computer. Therefore, the beam spot size and location, corresponding to the size and the location of the measurement electrode, can be adjusted easily by focusing or moving the laser beam.

Abstract: An apparatus (1) for measuring physiological parameters has a test chamber (2) having boundaries defined by a first semiconductor chip (3) and a second semiconductor chip (4), between which chips a seal (7) bordering the test chamber (2) is arranged as a distance spacer. The first semiconductor chip (3) has an active side, which faces the test chamber (2) and has planar sensors, on which biological cells (6) located in a nutrient medium can be adherently deposited in order to measure physiological parameters directly on the cells (6). The second semiconductor chip (4) has on an active side, facing the test chamber (2), at least one additional sensor to measure global physiological parameters. The semiconductor chips (3, 4) are held in the sealing position using a mounting (8) that grasps over them on the outer side. Outside of the test chamber (2) the semiconductor chips (3, 4) each have electric connection contacts, which contact with opposing contacts of the mounting.

Abstract: The apparatus for measuring the intra-muscular fat in carcasses or parts of carcasses or the total content of fat in minced meat has a first pair of electrodes for insertion into a carcass or part of a carcass or into minced meat. An alternating current (AC) generator is connected to these electrodes. Second and third pairs of electrodes are inserted parallel to the first pair. Both the second and third pairs have measurement circuits to measure the voltage and phase between the electrode pairs after insertion. The needle or bar shaped electrodes are tapered and insulated apart from 5-20 mm long free end sections. Electrodes are separated by 10-100 mm with each electrode 10-50 mm from the nearest of the first electrode pair. The portable unit for on-line use has a display output. The AC frequency applied to the first electrode pair may be changed in an exponential series to give different measurements.

Abstract: A micro-electric detector provides conductivity or impedance based measurements of a test sample placed in a microchannel of a micro-analysis system. The detector includes a pair of electrodes disposed on opposing sidewalls of the microchannel to create a detection zone in the microchannel between and adjacent to the electrodes. A variety of test samples can be monitored by the detector, such as particulate-containing fluids and biological materials including living cells and subcellular structures. The detector can be integrated on-chip using micromachining techniques with a variety of micro-analysis systems.

Abstract: The invention relates to an apparatus and method for monitoring cells and to a method for monitoring changes in cells upon addition of an analyte to the cell's environment, comprising a device which includes an array of microelectrodes disposed in a cell culture chamber, upon which array a portion of cells adhere to the surfaces of the microelectrodes. The diameter of the cells are larger than the diameters of the microelectrodes. A voltage signal is applied across each of the microelectrodes and a reference electrode. Detection and monitoring of the signals resulting from the application of the voltage signal provides information regarding the electrical characteristics of the individual cells, including impedance (combined cell membrane capacitance and conductance), action potential parameters, cell membrane capacitance, cell membrane conductance, and cell/substrate seal resistance. Such an invention is useful in detecting or screening a variety of biological and chemical agents.

Abstract: An on-line somatic cell analyser and a method for measuring a somatic cell count (SCC) are provided. A flow cell is connected to a milking hose and admits a constant volume of sampled milk into the flow chamber. A probe with two electrodes is positioned in a zone of optimal sensing inside the flow chamber, and provides a modulated signal according to the number of sodium ions present in the sample. A control unit receives the modulated signal, generates an ion count, and compares same with a plurality of SCC thresholds for classifying the sample in a quality category. A set of parameters characterizing the respective quality category, as well as the presence of mastitis in the animal, are finally displayed.

Abstract: An electrochemical biosensor test strip with four new features. The test strip includes an indentation for tactile feel as to the location of the strips sample application port. The sample application port leads to a capillary test chamber, which includes a test reagent. The wet reagent includes from about 0.2% by weight to about 2% by weight polyethylene oxide from about 100 kilodaltons to about 900 kilodaltons mean molecular weight, which makes the dried reagent more hydrophilic and sturdier to strip processing steps, such as mechanical punching, and to mechanical manipulation by the test strip user. The roof of the capillary test chamber includes a transparent or translucent window which operates as a "fill to here" line, thereby identifying when enough test sample (a liquid sample, such as blood) has been added to the test chamber to accurately perform a test. The test strip may further include a notch located at the sample application port. The notch reduces a phenomenon called "dose hesitation".

Abstract: The invention relates to an apparatus and method for monitoring cells and to a method for monitoring changes in cells upon addition of an analyte to the cell's environment, comprising a device which includes an array of microelectrodes disposed in a cell culture chamber, upon which array a portion of cells adhere to the surfaces of the microelectrodes. The diameter of the cells are larger than the diameters of the microelectrodes. A voltage signal is applied across each of the microelectrodes and a reference electrode. Detection and monitoring of the signals resulting from the application of the voltage signal provides information regarding the electrical characteristics of the individual cells, including impedance (combined cell membrane capacitance and conductance), action potential parameters, cell membrane capacitance, cell membrane conductance, and cell/substrate seal resistance. Such an invention is useful in detecting or screening a variety of biological and chemical agents.

Abstract: A skin condition analyzer with selectable modes of operation includes a probe apparatus for generating a skin condition signal representative of the moisture content of the skin and a processor that adjusts the skin condition signal in accordance with environmental components, such as temperature and humidity, to arrive at an overall skin condition signal. The skin condition is displayed visually and communicated audibly through a voice synthesizer system, having selectable languages. The modes of operation include single point random measuring and multiple point patterned measuring for compiling a composite skin analysis report.

Abstract: A method and apparatus for measuring resistance of a blood sample in order to determine the hematocrit of that blood sample. The present invention makes a direct ratiometric measurement. That is, the alternating current that flows through the sample is directly measured by applying that alternating current to an integrator which converts the current to a D.C. voltage which is directly proportional to the applied current.

Abstract: A touch sensor circuit is disclosed for sensing a person's touch and for switching power to an AC load. The touch sensor circuit includes a sense input circuit, logic circuit, power switching circuit and power supply/reference circuit. The power supply and reference circuit tracks the AC line-hot input, and supplies DC power to the circuit. The sense input circuit is configured such that when a person touches the touch input pad, a circuit is created between the positive voltage reference and earth ground, thereby generating an easily detectable voltage swing on an internal sensing node. The logic circuit senses the voltage variation on the sensing node and generates a pulse which toggles power to the power switching circuit and connected load.

Abstract: This invention provides an improved system for monitoring and recording cell cultures. A method for measuring a delay period for an alternating current voltage applied across a pair of pins improves the stability of measurements made with the improved system. A method for applying a voltage across a pair of pins which avoids exceeding a pre-established voltage avoids the possibility of damaging and/or destroying cells while monitoring their culture.

Abstract: A contact hazard meter used to measure electromagnetic field induced currents which would flow through a human body to ground upon physical contact with an item carrying such field induced currents includes a conductive contact, a human equivalent circuit coupled to the conductive contact and an electronic circuit coupled to the human equivalent circuit for measuring and displaying a measurement of current flowing from the item and through the human equivalent circuit when the conductive contact is placed in physical contact with the item carrying the field induced currents. The human equivalent circuit approximates the impedance of the human body at varying frequencies. The contact hazard meter has a plurality of range settings, one setting providing the resultant current as a percentage of a safety guideline maximum permissible exposure value.

Abstract: Cellular biological material (such as living tissue) is analysed or monitored by applying an AC electrical potential across the biological material so as to produce a nonlinear dielectric spectrum, and obtaining a detectable signal corresponding to the resulting spectrum. The potential is of a first frequency and the measured response at one or more second frequency substantially not overlapping with the first frequency.

Abstract: A cell potential measurement apparatus, which uses a planar electrode enabling a multi-point simultaneous measurement of potential change arising from cell activities, is provided which can conduct measurements accurately and efficiently as well as can improve convenience of arranging measurement results.

Abstract: Impedance measurements from an array of cells containing microorganisms whose growth or multiplication are to be measured in terms of the impedance, utilizes electrodes which can be introduced into the cells and have contact pieces engageable by one or more probes of a measuring head displaceable by an x, y carriage system into alignment with the successive contact pieces. The system avoids the need for voluminous conductor arrangements and multiplexing systems.

Abstract: An apparatus is so constructed as to measure a specific substance in a test specimen by the degree of the aggregation of carrier particles in a reaction solution in which the test specimen is mixed with the carrier particles which carry a substance specifically binding to the specific substance. The apparatus includes a substrate having comb-shaped electrodes mounting the reaction solution and amplifier and alternating oscillator for displaying a variable voltage to the comb-shaped electrodes. The test specimen measuring apparatus having the structure accelerates the aggregation of the reaction solution by applying an alternating voltate to the comb-shaped electrodes in a state that the reaction solution is being mounted on the substrate, and detects the spatial spectrum of the comb-shaped electrodes on which the reaction solution is mounted, thus performing the qualitative or quantitative detection of the presence of the substance in the test specimen.

Abstract: A device for providing a signal emulating the wetness of plant leaves, includes a first generally horizontal surface; a second, generally upwardly facing sloped surface having an edge spaced above the first surface by a gap, so that drops of moisture can accumulate on the second surface, and run off the edge, bridging the gap, and first and second leads extending from the first and second surfaces, respectively, to measure the conductivity/resistivity across the gap. Also disclosed is a method of providing a signal emulating the wetness of plant leaves including the steps of: providing a first generally horizontal surface; providing a second, generally upwardly facing sloped surface having an edge spaced above the first surface by a gap, so that drops of moisture can accumulate on the second surface, and run off the edge, bridging the gap between the first and second surfaces; and measuring the conductivity/resistivity across the gap between the first and second surfaces.

Abstract: A conductance measurement circuit to measure conductance of a solution under test with an output voltage proportional to conductance over a 5-decade range, i.e., 0.01 uS to 1000 uS or from 0.1 uS to 10,000 uS. An increase in conductance indicates growth, or multiplication, of the bacteria in the test solution. Two circuits are used each for an alternate half-cycle time periods of an alternate squarewave in order to cause alternate and opposite currents to be applied to the test solution. The output of one of the two circuits may be scaled for a different range optimum switching frequency dependent upon the solution conductance and to enable uninterrupted measurement over the complete 5-decade range. This circuitry provides two overlapping ranges of conductance which can be read simultaneously without discontinuity thereby eliminating range switching within the basic circuitry.

Abstract: Apparatus and method for measuring power density in an energized volume of water using either a measurement of voltage gradient or current density for use in determining optimal electrical power parameters for electrofishing, in-water electroshocking, electrical barrier control and the like. Specific probes for either measurement are disclosed. A calculator or programmed microprocessor receives measurements of current density or voltage gradient and water conductivity at a selected location within an energized liquid body and performs the mathematical operations necessary to calculate power density. Values on a graph of water conductivity, current density, voltage density and power density are used to determine how much electrical power to apply to a specific organism in a specific volume of liquid.

Abstract: A method and apparatus for performing an enzyme-linked immuno sorbent assay of a biological substance in a fluid substrate wherein an enzyme conjugate is used to react with the biological substance to cause the release of ions into the substrate. The change in the resistivity of the substrate due to the release of ions is measured, and an analog signal is generated in response thereto. The analog signal is converted into a digital signal, which is quantized and output in a human readable form for indicating the quantity of the biological substance present in the substrate.

Abstract: Apparatus and method for measuring power density in an energized volume of water using either a measurement of voltage gradient or current density for use in determining optimal electrical power parameters for electrofishing, in-water electroshocking, electrical barrier control and the like. Specific probes for either measurement are disclosed. A calculator or programmed microprocessor receives measurements of current density or voltage gradient and water conductivity at a selected location within an energized liquid body and performs the mathematical operations necessary to calculate power density. Values on a graph of water conductivity, current density, voltage density and power density are used to determine how much electrical power to apply to a specific organism in a specific volume of liquid.

Abstract: An apparatus and method for monitoring cell-substrate impedance comprises upper and lower substrates each containing strips of metal foil which cross to form well areas. Holes in the upper substrate expose an insulation layer between the upper and lower substrates. Smaller holes in the insulation layer expose the conductive material of the lower substrate. Cylindrical well walls are positioned around each of the holes in the upper substrate and define a cell medium containing well which is exposed to an annular area of conductive foil on the upper substrate, and a small area of conducive foil on the lower substrate. The areas of foil form large and small electrodes which are positioned in an array of wells which can be used to monitor the impedance of various cell cultures under various conditions. A switching device applies currents to the well electrodes and a monitoring device measures the impedance between the electrodes in each well. In this way, cell spreading and motility can be measured.

Abstract: Apparatus for testing shelled corn in a combine storage tank during harvesting includes a plurality of charged electrodes each in the form of an elongated rod arranged in a spaced manner and positioned in a lower portion of the combine storage tank to be completely encompassed by the shelled corn. The electrodes are coupled to a moisture meter located in the combine cab allowing the operator to determine the moisture content of the corn crop at harvest. The moisture meter is easily disconnected from the electrodes and removed from the combine to permit moisture testing of corn kernels while still on the cob prior to harvest.

Abstract: A conductivity measuring device comprises a low-potential intermediate electrode which is capable of being in connected state by a switch and which is disposed between a couple of measuring electrodes for transmitting and receiving. Each of said electrodes is made contact with a body to be tested so that the conductivities of the surface and the inner portion of said body to be tested can be measured, respectively.

Abstract: Apparatus for indicating a predisposition to kidney stone disease in humans, and also dehydration, and for monitoring the efficacy of hydration therapy, comprises a conductivity probe including a tip which can be inserted into urine so that a drop thereof adheres to the tip, and display means for indicating the result as a derived function of conductivity (electrolyte concentration) in terms of urine specific gravity or osmolality. Preferably the probe electrodes are small and are spaced closely together so that the streamlines between the electrode tips are such that maximum current flows substantially within the adherent drop of urine.

Abstract: The device comprises: a high frequency alternating voltage generator the output of which is connected to a sensor probe 5 which is to be applied to a substrate to be measured, an amplifier the input of which is connected to the sensor probe, and a detector arranged to furnish a D.C. voltage signal based on the output from amplifier. The generator, the amplifier and the detector are located inside a metal envelope enclosure. An electromagnetic radiation shield is disposed inside the envelope to separate the amplifier and the detector from the high frequency generator. In operation, voltage output from the detector is indicative of the electrical impedance of the substrate as sensed at the probe. In the preferred application, the substrate is skin and the measured electrical impedance is indicative of the water content of the skin.

Abstract: A circuit is described for applying a potential to an electrode of a biosensing test cell, which electrode, when properly inserted in a female connector, is contacted by a pair spaced apart contacts. The circuit includes a source of excitation potential and an operational amplifier having one input connected to the source of excitation potential. A switching circuit is coupled between the operational amplifier and a first one of the spaced apart contacts, with the switch means exhibiting an impedance. A feedback circuit is connected between the second of the spaced-apart contacts and another input to the operational amplifier, to feed back a potential appearing at the second contact. The feedback is for the purpose of maintaining the output of the operational amplifier at a level which compensates for impedance losses in the swtiching circuit.

Abstract: A first exemplary embodiment of an osmometer for the in vivo measurement of the osmolarity of a bodily fluid such as tears or sweat comprises a detachable, preferably disposable, probe in combination with means for measuring the conductivity between two electrodes of the probe. The osmometer further comprises means for converting the measured value of conductivity of the in vivo sample into a corresponding value of osmolarity and display means for displaying a visible representation of that value.In a second exemplary embodiment a sensor of some physical quantity (such as dew point temperature) related to the vapor pressure from a bodily fluid is mounted inside a confining, generally concave shell which is placed adjacent to a portion of the human body for a measurement to be made. For the case of measuring tear osmolarity in the open eye, the confining shell could take the form of a conventional eyecup.

Abstract: This invention relates to the measurement of the moisture content retained in the skin, and enables accurate diagnosis of the skin conditions by a device which can be switched in the connection of measurement electrodes to measure the moisture content either in the surface or in the depth of the keratinous layer of the skin.

Abstract: A corn moisture tester is adapted to measure the moisture content of corn kernels on an ear of corn. The ear of corn may be affixed to the corn stalk. The device includes an ear cradle, a pair of electrode blades and circuit for measuring a moisture-dependent electrical property of the corn kernels. The cradle is adapted for receiving an ear of corn and includes two portions hinged together so they may be opened to receive the ear. When the cradle portions are closed, they form a substantially cylindrical interior cradle surface for engaging the ear of corn. The conductor blades are mounted to one portion of the cradle to pierce the kernels but not the cob when the cradle is closed about an ear under test. The electrical property measuring circuit generates and displays a signal representative of moisture.