Abstract: Apparatus and methods for detecting the presence of an airborne chemical or biological analyte utilize: a substantially gas- and liquid-impermeable container; means for introducing a substantially analyte-free collection liquid into said container; means for rapidly sampling ambient air and transferring said analyte therefrom into said collection liquid, said sampling means comprising an air intake means and and an air venting means; and means for removing from said container an analyte-enriched collection liquid; wherein said volume of air passes through a substantially horizontal air inlet and downward through a substantially vertical collector electrode tube with means for applying an electric field between said tube and a co-axial spiked wire- or rod-shaped discharge electrode.

Abstract: In an improved amperometric gas sensor, the structure, composition, and electrode potential are adjusted so as to prevent or minimize any unwanted reactivity at the counter and/or reference electrode of any analyte or interfering component of the matrix that may cross over thereto. The sensor is preferably structured so that the product of the analyte reaction at a first working electrode can be reconverted to the original analyte at a counter electrode or at a second working electrode and then reacted again at the first working electrode, with such back-and-forth reactions repeating many times, so as to yield an amplification of the analyte signal.

Abstract: Air is sampled at a rate in excess of 100 L/min, preferably at 200-300 L/min, so as to collect therefrom a substantial fraction, i.e., at least 20%, preferably 60-100%, of airborne particulates. A substance of interest (analyte), such as lead, is rapidly solubilized from the the collected particulates into a sample of liquid extractant, and the concentration of the analyte in the extractant sample is determined. The high-rate air sampling and particulate collection may be effected with a high-throughput filter cartridge or with a recently developed portable high-throughput liquid-absorption air sampler. Rapid solubilization of lead is achieved by a liquid extractant comprising 0.1-1 M of acetic acid or acetate, preferably at a pH of 5 or less and preferably with inclusion of 1-10% of hydrogen peroxide. Rapid determination of the lead content in the liquid extractant may be effected with a colorimetric or an electroanalytical analyzer.

Abstract: The presence of carcinogens in air, soils, and other areas is detected by combining liquid-assisted air sampling with means for testing liquid samples for mutagenicity. Hazardous or illicit substances or pathogens which may be buried in the ground or otherwise concealed or present in contaminated food at various stages of food processing are detected using a two-line probe such that one of the lines directs exhaust air from the sampler onto suspect surfaces so as to dislodge and blow off droplets, particles or insects therefrom while the other line draws some of them into the sampler. Variants of said two-line probe can also serve to collect lead, hexavalent chromium or other harmful substances and bacterial, fungal or viral pathogens from crumbling walls or floors. Liquid-assisted air sampling can also serve to capture disease-transmitting insects and detect and identify insect-borne pathogens.

Abstract: The presence of carcinogens in air, soils, and other areas is detected by combining liquid-assisted air sampling with means for testing liquid samples for mutagenicity. Hazardous or illicit substances or pathogens which may be buried in the ground or otherwise concealed or present in contaminated food at various stages of food processing are detected using a two-line probe such that one of the lines directs exhaust air from the sampler onto suspect surfaces so as to dislodge and blow off droplets, particles or insects therefrom while the other line draws some of them into the sampler. Variants of said two-line probe can also serve to collect lead, hexavalent chromium or other harmful substances and bacterial, fungal or viral pathogens from crumbling walls or floors. Liquid-assisted air sampling can also serve to capture disease-transmitting insects and detect and identify insect-borne pathogens.

Abstract: A surgical snare instrument includes an elongated tubular sheath having proximal and distal ends, a flexible torqueable shaft having proximal and distal ends extending through and axially movable relative to the sheath, a snare loop at the distal end of the shaft, and a handle coupled to the proximal ends of the sheath and shaft for moving the shaft relative to the sheath and for rotating the shaft relative to the sheath so that the snare loop, when extended beyond the distal end of the sheath, is rotatable relative to the distal end of the sheath. The shaft is preferably a multifilament twisted and drawn cable. The filaments of the multifilament twisted and drawn cable are preferably either stainless steel, nickel-titanium alloy, or a combination of the two. Such a shaft has been demonstrated to provide the high torqueability necessary for controlled rotation of the snare loop.

Abstract: Apparatus and methods for detecting selected chemical compounds in air or other gas streams at room or ambient temperature includes a liquid-free humidity-resistant amperometric sensor comprising a sensing electrode and a counter and reference electrode separated by a solid electrolyte. The sensing electrode preferably contains a noble metal, such as Pt black. The electrolyte is water-free, non-hygroscopic, and substantially water-insoluble, and has a room temperature ionic conductivity ≧10−4 (ohm-cm)−1, and preferably ≧0.01 (ohm-cm)−1. The conductivity may be due predominantly to Ag+ ions, as in Ag2WO4.4AgI, or to F− ions, as in Ce0.95Ca0.05F2.95. Electrical contacts serve to connect the electrodes to potentiostating and detecting circuitry which controls the potential of the sensing electrode relative to the reference electrode, detects the signal generated by the sensor, and indicates the detected signal.

Abstract: A portable dental apparatus for treating patients or animals in remote locations comprises a dental drill driven by an air turbine; a pressurized air supply for driving the turbine and for pressurizing a water supply; and connections and valving for operating the drill and cooling it with a stream of water from the water supply and for squirting air or water from the air and water supplies with a squirt nozzle. Tile pressurized air supply derives its air from manual pumping, preferably with a double-action pump and a check valve to minimize fluctuations in the air flow rate. Such a pump either forms part of the air supply or is used to fill an inflatable container. The air supply may consist of the inflatable container alone, or of one or two double-action pumps, or of the container and one pump.

Abstract: Apparatus for the detection of a vapor of a selected chemical substance includes a sensor whose impedance changes upon exposure to such a vapor. The sensor comprises a polymer whose physical structure is altered by the vapor, e.g., through expansion or disintegration, and electrically conductive elements that are interspersed with or separated by the polymer. The interspersed elements may consist of a fine powder of carbon or of a metal in a matrix of silicone or other vapor-sensitive polymer. The electrical contacts between the powder particles are weakened when the polymer swells or disintegrates, which results in increased resistance. Alternatively, the capacitance between two conductive layers separated by a polymer layer decreases, and hence the impedance increases, when the polymer swells upon exposure to the vapor. In yet another embodiment, the polymer exerts a stress on a piezoresistive element and the stress is increased when the polymer swells, which causes a further increase in resistance.

Abstract: In solid-state chemical sensors, such as the highly sensitive and selective sensor for the detection of halogenated compounds comprises a bead of sodium lanthanum fluoride silicate, having the molecular formula NaLa.sub.4 (SiO.sub.4).sub.3 F, the performance and lifetime are adversely affected by a build-up of insulating reaction product between two electrodes. To prolong the lifetime, intermittent sensor operation is achieved by applying a voltage between the sensor electrodes during only a small fraction of each measurement cycle and/or by reversing the voltage in successive measurement intervals and/or by switching the connections between additional reserve electrodes and/or by periodically exposing the sensor to chemically filtered air at regular time intervals during a major fraction of each measurement cycle. The response speed and sensitivity of the NaLa.sub.4 (SiO.sub.4).sub.

Abstract: A relatively inexpensive modular component that can be substituted for, or used in conjunction with, an existing smoke detector in a commercially available residential fire-detection alarm comprises: (A) an amperometric sensor for carbon monoxide, in which the reference and counter electrodes are combined either internally into a single auxiliary electrode or externally by electrical shorting; and (b) a simple current-to-voltage converter circuit that converts the current signals from the sensing electrode into amplified voltage signals. The converter circuit is powered by the same battery (usually a 9-volt dry cell) and is connected to the same alarm-triggering circuit that are used in existing residential fire alarms. The sensor-and-converter module is designed to fit into a commercially available smoke-detector-type fire alarm unit. The electrical output of the module is designed to be compatible with the electrical input requirements of the commercial detection circuitry.

Abstract: An optical waveguide sensor for the detection of acid vapors comprises a chemically sensitive reagent coating of bromothymol blue or thymol blue indicator suspended in a Nafion polymer film. The sensor uses a 562-nm light-emitting diode source and a phototransistor detector. The response to HCl and H.sub.2 S vapors is both rapid and reversible, with an estimated detection limit for H.sub.2 S of less than 15 ppmv (parts per million by volume). The sensor exhibits generalized response to protonic acid vapors, but does not produce an indicator response to CO.sub.2, even at large concentrations (60 volume-%) in the presence of water vapor. The sensor exhibits a systematic interference from water vapor which may be corrected by a differential approach, either using a reference sensor (Nafion without an indicator) or by monitoring the sensor responses at two wavelengths.

Abstract: Selective detection of an analyte in a gaseous mixture is achieved by a chemical, especially amperometric, sensor, that is responsive to the analyte, and a pump-and-valve system, controlled by programmed electronic circuitry, which causes: a) ambient air to pass first through a chemical filter, that removes those air constituents to which the sensor may be responsive, and next through a sorbent-containing tube and the sensor; b) a portion of the gaseous mixture to be first drawn into a sample port and next flushed from the port into the sorbent tube; c) analyte-containing eluent from the sorbent tube to reach the sensor; and d) another mixture component to which the sensor may be responsive to be prevented from reaching the sensor. The sorbent-containing tube has a different retentivity for the analyte than for the other mixture component. The air flow rates and paths can be programmed and the volume of the mixture portion may be auto-ranged to maximize the accuracy of the sensor signals.

Abstract: An electric circuit, well concealed within a purse or satchel, comprises an alarm in series with a battery and a switch, said switch being kept open by a uniquely shaped prong inserted into a matching hole. Withdrawal of said prong results in closure of the switch and activation of the alarm. A switching means is recessed within the matching hole in such a manner that mere insertion therein or poking with a sharp-tipped object can not suffice to deactivate the alarm. A cord or wire attachable to both the prong and a part of the owner's body effects withdrawal of the prong, and hence triggering of the alarm, when the purse or satchel is pulled away from said body part, or vice versa, through an action of either a robber or of an owner in distress.

Abstract: Improved methods and devices for cultivating a young plant comprise temporary insertion into the soil close to and around said plant of a substantially impervious material so as to form a small enclosure assuring retention of most nutrients near said plant. Small perforations in said material permit drainage of excess water from said enclosure. Identations along lines joining said perforations facilitate breaking, tearing or cutting of the material to an appropriate size. A sharp leading edge may be provided along the perforations and indentations to facilitate insertion of the material in the soil around the plant. The material may be in form of an assortment of tubes or of a sheet adaptable to being bent into a cylindrical or conical configuration.

Abstract: The current-carrying capacity of a fluidized-bed electrode is enhanced by imparting increased velocities to the particles suspended therein while maintaining a relatively low degree of bed expansion or voidage. This is accomplished in one embodiment of the invention by means of pairs of opposing jets of electrolyte impinging against each other so as to effect a highly turbulent motion of the fluidized particles while the net flow velocity of the supporting electrolyte is kept relatively low. In a second preferred embodiment, the electrolyte flow velocity may be as high as desired, but its direction, preferably horizontal, is reversed at frequent intervals. The suspended particles get thereby intermittently packed against and retained by filters at the alternating outlet walls. The alternating packing and expansion result in improved charge and mass transport, and hence in improved electrode performance.