Abstract: A differential polarimeter is disclosed for detecting changes in optical rotation between a test cell and reference cell. The test cell contains a fluid sample exposed to an analyte specific enzyme; the reference cell contains a fluid sample not exposed to the enzyme. To enhance the sensitivity of the system a phase sensitive differential polarimetric technique is taught. In this technique, the phase difference between two resulting sinewave voltages is a measure of analyte concentration.

Abstract: The invention concerns an implantable, inflatable helical cuff which is wrapped about a tubular body member such as a nerve cord, esophagus, colon, intestine, or blood vessel in a pressure transferring relationship. The cuff may be completely inflated to function as an occluder, or partially inflated to function as a pressure sensor or transducer in an appropriate system.

Abstract: An apparatus for detecting the presence and/or measuring the concentration of an analyte in the fluid medium is disclosed. The apparatus relies on biospecific binding between a biochemical binding system and the analyte to change the dielectric properties of a capacitive affinity sensor. The biological affinity sensor is optimized by: (1) adjusting the thickness and dielectric properties of a passivation layer to generally match the impedance of the biological binding system; and (2) minimize the double layer capacitance so that bulk capacitance changes associated with the biological binding system are maximized.

Abstract: A sintered powder electrode has a biochemically active layer embedded in pores of the electrode. Molecules bind to or are displaced from the biochemically active layer, which drastically changes electrical properties of the electrode. The electrode can be used in an affinity chromotography column or in a capacitive affinity sensor.

Abstract: An apparatus for detecting the concentration of certain analytes, including hydrocarbons, in a liquid medium, is disclosed. The apparatus uses a planar or "open" capacitor containing an active layer. In response to selected analyte in the liquid medium, the active layer causes capacitance to decrease with increasing analyte concentration. The capacitance decreases because higher dielectric water molecules are displaced from a region of the capacitor's electric field. For certain hydrocarbon analytes having high Henry's Law constants, the active layer causes bubbles to nucleate in the liquid medium on the surface of the active layer. Bubble formation displaces water molecules and decreases capacitance.

Abstract: This invention relates to an apparatus and method for regulating the exposure of active surfaces by covering the surface with an erodible protection coating. The rate of erosion is controlled by chemical and/or physical means so that the surface is progressively and gradually exposed.

Abstract: An improved apparatus for inhibiting self-injurious behavior (SIB) in patients includes a stimulus module for generating and applying an aversive electrical stimulation to the patient's skin and a sensor module and/or remote actuator for actuating the stimulus module in response to a patient's self-injurious behavior. The apparatus uses a near field magnetic link to transmit a coded signal from a sensor module or from a remote actuator to the stimulus module worn on the patient. The stimulus module uses a unique flyback circuit design and the electrical stimulation is tuned to achieve a maximum physiological response with minimal power drain.