Abstract: A capacitive sensing system is used to measure a time-varying ion current through a channel, such as an ion channel or protein pore. Such a capacitive system does not suffer problems of electrode corrosion and, when used with methods to control a build up of ion concentration, allows the use of measurement volumes around the channel with dimensions on a scale of nanometers.

Abstract: The sequencing of individual monomers (e.g., a single nucleotide) of a polymer (e.g., DNA, RNA) is improved by reducing the motion of the polymer due to thermally-driven diffusion to reduce the spatial error in the position of the polymer within a measurement device. A major system parameter, such as average translocation velocity or measurement time, is selected based on the characteristics of the sensing system utilized, and an algorithm jointly optimizes the sequencing order error rate and the monomer identification error rate of the system.

Abstract: An apparatus and method for sensing time varying ionic current in an electrolytic system having a first fluid chamber and a second fluid chamber separated by a barrier structure is provided, wherein the barrier structure includes thick walls and a substrate having an orifice therein, with the first and second fluid chambers being in communication via the orifice. A potential is applied between electrodes in respective first and second fluid chambers, thus driving an electrical current between them and through the orifice. Total capacitance of the system is less than 10 pF. Analytes are added to one of the first and second fluid chambers and time varying ionic current that passes across the orifice is measured. An amplifier proximal to the barrier structure and electrodes amplifies the ionic current signal.

Abstract: A self-locating mounting apparatus for holding objects such as sensors at specific positions on a subject's head includes a central mount constituted by a plurality of inextensible elements adapted to fit over the top of a subject's head. In addition, the mounting apparatus includes an adjustable circumferential band adapted to circle the subject's head and connect the central mount to inextensible side elements via sliding joints. A plurality of biasing elements provide a force for biasing sensor mounting units on the mounting apparatus against a subject's head, allowing for long-term sensing while minimizing interference forces on the mounting units. Advantageously, the mounting apparatus holds sensors within approximately 5 mm of their desired measurement positions over a range of subject head sizes.

Abstract: An integrated array of electronic sensing elements outputs a bio-fingerprint of an analyte. System is preferably constructed of as a series of three layers but need not be so arranged. An upper layer defines a fluid volume or analyte chamber; a middle layer contains the sensing elements; and a third layer contains electronic readout elements. The analyte chamber contains an electrolyte and the analyte to be detected. The sensing elements are optimized for maximum detection sensitivity in the minimum response time. The response of each sensing element is read out by a dedicated sensing electrode. Around each electrode is a control ring. The potential of the control ring is set to attract analytes of interest to the sensing elements.

Abstract: An underwater EM measurement system, which is substantially smaller, much simpler to use, and more robust than prior systems, is formed as a sensor package integrated into a single pressure vessel includes two magnetic sensors including induction coils disposed substantially horizontally so as to measure fields in orthogonal directions. The package also includes two electric field sensors including electric potential antennas adapted to couple to a water potential via a capacitive electrode having a conducting material and an electrically insulative layer formed of an insulating material. The capacitive electrode has a capacitance to the medium of greater than 1 mF. Preferably, the insulating material is a metal oxide.

Abstract: An integrated fluxgate-induction sensor is formed of a combined fluxgate sensor and induction sensor using a common core. The sensor may be in serial operation where it switches between a fluxgate mode for measuring static magnetic fields and an induction mode for measuring alternating magnetic fields. Additionally, the sensor may be used in an interleaved operation where the sensor operates from the fluxgate mode during the transition period where its core is changing from a high permeability state to a low permeability state or vice versa, while the sensor operates in the induction mode when the core is in its high permeability state. The resulting sensor provides for a compact magnetic sensor system capable of sensing magnetic fields which oscillate from zero frequency to 10 kHz and higher.

Abstract: A compact sensor system integrates electric and magnetic field sensors to accurately measure, with a high level of sensitivity, electric and magnetic fields. The sensor system is self-contained so as to include a built-in power source, as well as data storage and/or transmission capability. The integrated sensor system also preferably includes a global positioning system (GPS) to provide timing and position information, a sensor unit that can determine the orientation and tilt of the sensor system, and self-calibrating structure which produces local electric and/or magnetic fields used to calibrate the sensor system following deployment. The system measures the electromagnetic signals produced by lightning and more has the capability to determine the direction and distance to a lightning event without input from sensors at other locations. Furthermore, the system can detect both conventional short-duration lightning events and also the less common, but more destructive, continuing current lightning.

Abstract: A magnetic detection system to be used by security personnel for the purpose of discovering hidden or otherwise concealed objects being brought into or taken out of a defined or screened area employs magnetic induction sensors and, more particularly, a support structure that holds one or more sensors in a defined orientation relative to an object to be screened. The system can also include auxiliary components, such as a cancellation unit for nullifying an interfering environmental field, a camera for taking photographs or video of a subject, and presence sensors for use in verifying or signaling the existence of a subject to be screened.

Abstract: An electrolytic sensing system for measuring a blocking signal allows for controlled translocation of a molecule, such as DNA, through a fluid channel. A substantially constant electric field supplied by a DC source is applied across the fluid channel and induces translocation of the molecule within the system. An oscillating electric parameter (e.g. current or voltage) supplied by an AC source is also applied across the fluid channel as a means for measuring a blocking signal. The substantially constant electric field can be altered to provide more detailed control of the molecule and, optionally, run a select portion of the molecule through the channel multiple times to provide numerous signal readings. A temperature control stage cools the system, providing further control of molecule translocation. A modified or non-modified protein pore may be utilized in the fluid channel. The system allows for long DNA strands to be sequenced quickly without amplification.

Abstract: A sensor system accurately measures, with a high level of sensitivity, one or more vector components of a small electric field, through the use of multiple, relatively fixed sensors, at least one of which constitutes a weakly coupled capacitive sensor. The sensor system enables the electric field to be determined in a direction normal to a surface or along multiple orthogonal axes. Measurement of the electric field vector can provide improved resolution and characterization of electrical signals produced, for example, by organs within the human body.

Abstract: A compact sensor system integrates electric and/or magnetic field sensors to accurately measure, with a high level of sensitivity, one or more electric and magnetic vector components of fields. The electric and magnetic field data can be utilized separately or combined. The sensor system is self-contained so as to include a built-in power source, as well as data storage and/or transmission capability. The integrated sensor system also preferably includes a global positioning system (GPS) to provide timing and position information, a sensor unit which can determine the orientation and tilt of the sensor system, and self-calibrating structure which produces local electric and/or magnetic fields used to calibrate the sensor system following deployment.

Abstract: A system and method for non-invasively measuring the electrical potential radiated by a cell. To do this, a probe is positioned within ten microns distance from the cell for receiving the signal. Also, a reference potential is determined for the cell's environment. A sensor records the signal and compares the reference potential to the cell's signal to measure the electrical potential of the cell.

Abstract: A system for measuring a biopotential signal produced by a body in free space at a location adjacent to the body, and if desired, through clothing, includes a probe that can be positioned adjacent to the body. The probe includes a conductive electrode to receive the biopotential signal and a conductor that is maintained at a fixed distance from the electrode. The potential of the conductor can be maintained substantially equal to the potential of the electrode to shield the electrode from stray electrical noise. The system further includes a high impedance first stage amplifier that is incorporated into the probe and electrically connected to the electrode using a relatively short connector to minimize connector noise. Functionally, the first stage amplifier compares the electrical potential of the electrode to a second potential (e.g. a local ground) and generates a signal that is indicative of the biopotential.

Abstract: A system for measuring a biopotential signal produced by a body in free space at a location adjacent to the body, and if desired, through clothing, includes a probe that can be positioned adjacent to the body. The probe includes a conductive electrode to receive the biopotential signal and a conductor that is maintained at a fixed distance from the electrode. The potential of the conductor can be maintained substantially equal to the potential of the electrode to shield the electrode from stray electrical noise. The system further includes a high impedance first stage amplifier that is incorporated into the probe and electrically connected to the electrode using a relatively short connector to minimize connector noise. Functionally, the first stage amplifier compares the electrical potential of the electrode to a second potential (e.g. a local ground) and generates a signal that is indicative of the biopotential.

Abstract: A system and method for non-invasively measuring the electrical potential radiated by a cell. To do this, a probe is positioned within ten microns distance from the cell for receiving the signal. Also, a reference potential is determined for the cell's environment. A sensor records the signal and compares the reference potential to the cell's signal to measure the electrical potential of the cell.

Abstract: A sensitive detector and detector system with multi-state element or elements employing the phenomenon of stochastic resonance to enhance signal-to-noise ratio (SNR) and detector sensitivity. Signal output is enhanced by the addition of external noise at the input. A single detector element has these improved outputs. Several stochastic resonance elements may be connected in arrays to further increase SNR of the output, increase detector sensitivity, and linearize the relation between input and output.