Abstract: Methods and systems for operating a system that includes an array of sensors are described. In one example, output of sensors included in the array is characterized as being in one of a plurality of states. Diagnostics may be performed on sensors in the array of sensors based on sensors being in one of the plurality of states.

Abstract: Methods and devices including implantable micro-sensors used to detect tissue-dissolved inert gas and to detect microbubble formation to avoid Caisson disease are described. The disclosed methods and devices are based on measuring the refractive index changes in hydrophobic liquids after absorbing an inert gas such as nitrogen. The changes in the refractive index are based on implementing one of an interferometry, optical microcavity resonance shift, a photonic crystal resonance, a beam deflection, a resonance tuning or detuning, an amplitude change, or an intensity change method.

Abstract: An oxygen sensor (1, 2, 3, 4, 5) comprises a working electrode (WE) and a comparatively larger Ag/AgCl reference electrode (RE). A floating voltage between the electrodes (WE, RE) is temporarily retained and a measurement voltage is applied to between the electrodes (WE, RE) during a first period to cause reduction of oxygen and production of an evoked current at the working electrode (WE). The temporarily retained floating voltage is then applied between the electrodes (WE, RE) during a second period to produce a current out from the working electrode (WE). The pO2 in a liquid medium is then representative of a measured net charge to the working electrode (WE) equal to a sum of a charge transferred to the working electrode (WE) during at least a last part of the first period and a charge transferred to the working electrode (WE) during at least a last part of the second period.

Abstract: A cannula for transferring a substance to and/or from a patient includes a tubular support sleeve and a transfer tube. The support sleeve includes a rigid tubular member defining a lumen extending from a proximal end to a distal end of the tubular member. The transfer tube is positioned in the lumen and extends beyond each of the proximal end and the distal end of the tubular member. The tubular member includes a rigid, MRI-compatible material.

Abstract: Electrode configurations for electric-field enhanced performance in catalysis and solid-state devices involving gases are provided. According to an embodiment, electric-field electrodes can be incorporated in devices such as gas sensors and fuel cells to shape an electric field provided with respect to sensing electrodes for the gas sensors and surfaces of the fuel cells. The shaped electric fields can alter surface dynamics, system thermodynamics, reaction kinetics, and adsorption/desorption processes. In one embodiment, ring-shaped electric-field electrodes can be provided around sensing electrodes of a planar gas sensor.

Abstract: A cannula for transferring a substance to and/or from a patient includes a tubular support sleeve and a transfer tube. The support sleeve includes a rigid tubular member defining a lumen extending from a proximal end to a distal end of the tubular member. The transfer tube is positioned in the lumen and extends beyond each of the proximal end and the distal end of the tubular member. The tubular member includes a rigid, MRI-compatible material.

Abstract: The present invention relates generally to systems and methods for increasing oxygen availability to implantable devices. The preferred embodiments provide a membrane system configured to provide protection of the device from the biological environment and/or a catalyst for enabling an enzymatic reaction, wherein the membrane system includes a polymer formed from a high oxygen soluble material. The high oxygen soluble polymer material is disposed adjacent to an oxygen-utilizing source on the implantable device so as to dynamically retain high oxygen availability to the oxygen-utilizing source during oxygen deficits. Membrane systems of the preferred embodiments are useful for implantable devices with oxygen-utilizing sources and/or that function in low oxygen environments, such as enzyme-based electrochemical sensors and cell transplantation devices.

Abstract: An instrument and method for accurately measuring target analyte levels is a gas sample over an extended range. The instrument includes (i) a sensor effective for detecting the analyte, and (ii) a barrier film having limited permeability for the analyte covering the inlet orifice on the sensor for reducing the flux of analyte into the sensor. The method involves (a) sensing the flux of target analyte passing through the barrier film and into sensing contact with the sensor, and (b) reporting a concentration of analyte by multiplying a concentration value previously correlated to the sensed flux by the flux reduction factor of the barrier film.

Abstract: A method of determining the pH of an aqueous liquid which contains little or no buffer, such as does not contain more than 0.01 moles per litre of pH-buffering partially dissociated acid, base and/or salt, uses an electrode with at least one redox active compound immobilized thereon convertible electrochemically between reduced and oxidized forms with transfer of at least one proton between the compound and the aqueous liquid. Varying potential is applied to the electrode, observing current flow as potential is varied, determining the applied potential at a maximum current for redox reaction of the compound, and determining pH from the potential at maximum current. The electrode has a covering layer which separates the redox active compound from the aqueous liquid but selectively allows the passage of hydrogen ions between the redox active compound and the aqueous liquid. The presence of the covering layer enhances accuracy of the measurement of pH of the aqueous liquid.

Abstract: An electrochemical sensor for measuring the oxygen partial pressure in a process fluid, comprises an electrolyte-filled sensor body, which is covered on one side charged with the process fluid by an oxygen-permeable membrane, a cathode on the membrane, an annular guard electrode surrounding the cathode, which in measuring operation lies at the same potential as the cathode, an anode charged by the electrolyte in the sensor body, a reference electrode charged by the electrolyte in the sensor body, wherein between the anode and cathode a voltage can be applied, which is controlled between the cathode (8) and reference electrode at a constant polarization voltage and the measuring sensor current flowing in measuring operation between the cathode and anode is a measure for the oxygen partial pressure in the process fluid, and a test voltage source which can be switched in a testing mode between the cathode and guard electrode for producing test oxygen in the electrolyte and/or in the process fluid between the

Abstract: An electrochemical gas sensor includes a housing, a first working electrode within the housing and having a first section of gas transfer medium and a first layer of catalyst on the first section of gas transfer medium, and at least a second working electrode within the housing and having a second section of gas transfer medium and a second layer of catalyst on the second section of gas transfer medium. At least one of the first section of gas transfer medium and the second section of gas transfer medium includes at least one area in which the structure thereof has been irreversibly altered to limit diffusion of gas through the at least one of the first section of gas transfer medium or the second section of gas transfer medium toward the other of the at least one of the first section of gas transfer medium and the second section of gas transfer medium.

Abstract: An electrode for active oxygen species comprising a conductive component with a polymer membrane of a metal porphyrin complex formed on the surface is disclosed. The electrode for active oxygen species can detect active oxygen species such as superoxide anion radicals, hydrogen peroxide, and .OH and other active radical species (NO, ONOO—, etc.) in any environment including in vivo environment as well as in vitro environment. The electrode thus can be used for specifying various diseases and examining active oxygen species in food or in water such as tap water and sewage water.

Abstract: The present invention concerns an electrochemical sensor for determining oxygen dissolved in an aqueous measuring medium, a process for its production as well as a method for determining oxygen dissolved in an aqueous measuring medium using the electrochemical sensor.

Abstract: An electrochemical sensor for measuring the oxygen partial pressure in a process fluid, comprises an electrolyte-filled sensor body, which is covered on one side charged with the process fluid by an oxygen-permeable membrane, a cathode on the membrane, an annular guard electrode surrounding the cathode, which in measuring operation lies at the same potential as the cathode, an anode charged by the electrolyte in the sensor body, a reference electrode charged by the electrolyte in the sensor body, wherein between the anode and cathode a voltage can be applied, which is controlled between the cathode (8) and reference electrode at a constant polarization voltage and the measuring sensor current flowing in measuring operation between the cathode and anode is a measure for the oxygen partial pressure in the process fluid, and a test voltage source which can be switched in a testing mode between the cathode and guard electrode for producing test oxygen in the electrolyte and/or in the process fluid between the

Abstract: A BUN (blood urea nitrogen) sensor containing immobilized carbonic anhydrase and immobilized urease for the in vitro detection of urea nitrogen in blood and biological samples with improved performance and precision characteristics.

Abstract: The invention relates to a method for the controlled delivery of a drug as a function of bioavailable drug concentration, a sensor device for detecting bioavailable drug concentration, and a delivery device that controls delivery of the drug based on the real-time detection of bioavailable drug concentration.

Abstract: Embodiments of nanoelectronic sensors are described, including sensors for detecting analytes such ammonia. An environmental control system employing nanoelectronic sensors is described. A personnel safety system configured as a disposable badge employing nanoelectronic sensors is described. A method of dynamic sampling and exposure of a sensor providing a number of operational advantages is described.

Abstract: Disclosed herein are systems and methods for calibrating a continuous analyte sensor, such as a continuous glucose sensor. One such system utilizes one or more electrodes to measure an additional analyte. Such measurements may provide a baseline or sensitivity measurement for use in calibrating the sensor. Furthermore, baseline and/or sensitivity measurements may be used to trigger events such as digital filtering of data or suspending display of data.

Abstract: An electrochemical gas sensor for detecting ozone or nitrogen dioxide in a gas sample has a measuring electrode (3) formed of carbon nanotubes (CNT) or a counterelectrode (8) in an electrolyte solution (9), which contains lithium chloride or lithium bromide in an aqueous solution.

Abstract: The service life of amperometric electrochemical oxygen sensors is increased by operating the electrodes of such sensors at a polarization voltage suitable for measuring the oxygen content of samples only during calibration or when measuring such samples and thereafter modulating the polarization voltage to a lower voltage such that substantially no electrical current is produced by the electrodes.

Abstract: A BUN (blood urea nitrogen) sensor containing immobilized carbonic anhydrase and immobilized urease for the in vitro detection of urea nitrogen in blood and biological samples with improved performance and precision characteristics.

Abstract: A pellicle made of a polymer material contains fullerenes within the polymer material to reduce the damaging effects of radiation that is transmitted through the pellicle during an exposure operation. The fullerenes may comprise nanotubes and/or buckyballs. The buckyballs may also enclose molecules of a gas that further reduce the damaging effects of the radiation on the polymer material.

Abstract: A pellicle made of a polymer material contains fullerenes within the polymer material to reduce the damaging effects of radiation that is transmitted through the pellicle during an exposure operation. The fullerenes may comprise nanotubes and/or buckyballs. The buckyballs may also enclose molecules of a gas that further reduce the damaging effects of the radiation on the polymer material.

Abstract: A dissolved oxygen sensor having a cathode and anode immersed in an electrolyte is designed to provide a low background current in the sensor when a potential is applied to the cathode. The background current is maintained at a desired level by selecting the area and length of a channel or path of diffusion of residual oxygen in the electrolyte to the cathode. The area (A) of the diffusion channel in relation to its length (L) is selected to be at or below a selected ratio, A/L.

Abstract: Provided herein is a stabilized oxygen transport matrix that includes a reversible oxygen binding protein, such as hemoglobin, immobilized throughout the stabilized oxygen transport matrix. The stabilized oxygen transport matrix is used to transport oxygen and can be used as an oxygen transport region and a reaction region of an analyte sensor, such as an implantable glucose sensor. The reversible binding protein can also function as an oxygen probe within the analyte sensor.

Abstract: An oxide-ion conductor has the formula Ln1?xAxGa1?y?xB1YB2z oxide, wherein Ln is at least one element selected from the group consisting of La, Ce, Pr, Nd and Sm; A is at least one element selected from the group consisting of Sr, Ca and Ba; B1 is at least one element selected from the group consisting of Mg, Al and In; B2 is at least one element selected from the group consisting of Co, Fe, Ni and Cu; x is 0.05 to 0.3; y is 0 to 0.29; z is 0.01 to 0.3; and y+z is 0.025 to 0.3. The oxide-ion conductor exhibits higher oxide-ion conductivity than stabilized zirconia, excellent heat resistance and also high ion conductivity even at low temperatures, as well as exhibiting low oxygen-partial-pressure dependence of ion conductivity.

Abstract: A method and apparatus for detecting the presence of carbon monoxide in a gas which may also contain contaminating substances uses a pre-treatment means to absorb contaminating substances and to convert them to non-contaminating substances.

Abstract: Oxygen concentration measurement is carried out over a broad range by an instrument utilizing a zinc-air cell having a lower-than-nominal potential difference imposed across its electrodes by a shunt branch incorporating the source-drain circuit of a field effect transistor (FET). A feedback circuit is used to improve linearity of the output and cell life without sacrificing the broad dynamic range achieved by the use of the FET shunt branch.

Abstract: An electrochemical sensor for detecting the presence and amount of acetate in cell culture and fermentation media. The electrochemical sensor has a pH electrode, an internal reference electrode, a special high-tensile strength gas permeable membrane, and internal reference electrolyte such that acetate concentration can be measured using a pretreatment buffer having a pH of about 5.5.

Abstract: A process for operating an electrochemical measuring cell (1) is described, with which it is possible to carry out gas concentration measurements already shortly after switching on the measuring cell (1). The process includes the steps that potential voltage pulses are applied to the measuring cell (1) in a state of readiness of the measuring cell (1), in which the potential voltage is switched off. A system and device are also described.

Abstract: A method for determining the concentration of a reduced (or oxidised) form of a redox species in an electrochemical cell of the kind comprising a working electrode and a counter electrode spaced from the working electrode by a predetermined distance, said method comprising the steps of: (1) applying an electric potential difference between the electrodes; (2) selecting the potential of the working electrode such that the rate of electro-oxidation of the reduced form (or electro-reduction of the oxidised form) of the species is diffusion controlled, (3) selecting the spacing between the working electrode and the counter electrode so that reaction products from the counter electrode arrive at the working electrode; (4) determining current as a function of time after application of the potential and prior to achievement of a steady state; (5) estimating the magnitude of the steady state current, and (6) obtaining from the change in current with time and the magnitude of the steady state current, a value indicati