Abstract: Devices and methods are provided for determining the concentration of a reduced form of a redox species. For example, a device can include a working electrode and a counter electrode spaced by a predetermined distance so that reaction produces from the counter electrode arrive at the working electrode. An electric potential difference can be applied between the electrodes, and the potential of the working electrode can be selected such that the rate of electro-oxidation of the reduced form of the species is diffusion controlled. Current as a function of time can be determined, the magnitude of the steady state current can be estimated, and a value indicative of the diffusion coefficient and/or of the concentration of the reduced form of the species can be obtained from the change in current with time and the magnitude of the steady state current. Other embodiments of apparatuses, devices, and methods are also provided.

Abstract: Devices and methods are provided for determining the concentration of a reduced form of a redox species. For example, a device can include a working electrode and a counter electrode spaced by a predetermined distance so that reaction produces from the counter electrode arrive at the working electrode. An electric potential difference can be applied between the electrodes, and the potential of the working electrode can be selected such that the rate of electro-oxidation of the reduced form of the species is diffusion controlled. Current as a function of time can be determined, the magnitude of the steady state current can be estimated, and a value indicative of the diffusion coefficient and/or of the concentration of the reduced form of the species can be obtained from the change in current with time and the magnitude of the steady state current. Other embodiments of apparatuses, devices, and methods are also provided.

Abstract: A method of cleaning permeable, hollow membranes in an arrangement of the type wherein a pressure differential is applied across the walls of the permeable, hollow membranes immersed in a liquid suspension, the liquid suspension being applied to the outer surface of the porous hollow membrane to induce and sustain filtration through the membrane walls. The method of cleaning comprises the steps of applying a cleaning solution to one side of the membrane wall; applying a pressure differential across the membrane wall to cause flow of the cleaning solution through the wall from the one side of the membrane wall to the other side of the membrane wall and applying a reverse pressure differential across the membrane wall to cause flow of the cleaning solution through the wall from the other side of the membrane wall back to the one side of the membrane wall.

Abstract: Devices and methods are provided for determining the concentration of a reduced form of a redox species. For example, a device can include a working electrode and a counter electrode spaced by a predetermined distance so that reaction produces from the counter electrode arrive at the working electrode. An electric potential difference can be applied between the electrodes, and the potential of the working electrode can be selected such that the rate of electro-oxidation of the reduced form of the species is diffusion controlled. Current as a function of time can be determined, the magnitude of the steady state current can be estimated, and a value indicative of the diffusion coefficient and/or of the concentration of the reduced form of the species can be obtained from the change in current with time and the magnitude of the steady state current. Other embodiments of apparatuses, devices, and methods are also provided.

Abstract: A method of operating a membrane filtration module, the module including one or more membranes extending longitudinally between vertically spaced upper and lower headers into which the ends of the membranes are potted. The membranes have a permeable wall which is subjected to a filtration operation wherein feed containing contaminant matter is applied to one side of the membrane wall and filtrate is withdrawn from the other side of the membrane wall. At least one of the upper and/or lower headers has one or more openings therein and the method including flowing the feed, at least in part, through the one or more openings for application to the membrane wall. Apparatus for performing the method is also disclosed.

Abstract: A method of operating a membrane filtration module (5), the module (5) including one or more membranes (7) extending longitudinally between vertically spaced upper and lower headers (8, 9) into which the ends of the membranes (7) are potted. The membranes (7) have a permeable wall which is subjected to a filtration operation wherein feed containing contaminant matter is applied to one side of the membrane wall and filtrate is withdrawn from the other side of the membrane wall. At least one of the upper and/or lower headers (8, 9) has one or more openings (10) therein and the method including flowing the feed, at least in part, through the one or more openings (10) for application to the membrane wall. Apparatus for performing the method is also disclosed.

Abstract: A method of cleaning permeable, hollow membranes is disclosed. In one embodiment, the membranes are immersed in a liquid suspension. A pressure differential is applied across the walls of the membranes. During filtration, liquid suspension passes through the walls of the membranes to be drawn off as permeate, and at least some solids are retained on or in the membranes. The steps of cleaning include: applying a cleaning solution to one side of the membrane walls; applying a pressure differential across the membrane walls to cause flow of the cleaning solution through the walls from the one side of the membrane walls to the other side of the membrane walls; and, applying a reverse pressure differential across the membrane walls to cause flow of the cleaning solution through the wall from the other side of the membrane walls back to the one side of the membrane walls.

Abstract: A method of controlling fouling in a membrane filtration system (5) of the type where gas is used to clean or scour the membranes (6) wherein the method includes supplying the gas to the system with a continuously variable flow rate. A continuously variable valve arrangement (17) is also disclosed.

Abstract: A method of backwashing a membrane filtration module (4), said module (4) including one or more membranes (5) located in a feed-containing vessel (3), the membranes (5) having a permeable wall which is subjected to a filtration operation wherein feed containing contaminant matter is applied to one side of the membrane wall and filtrate is withdrawn from the other side of the membrane wall, the method including: removing liquid from the feed-containing vessel (3) until the level of liquid in the feed-containing vessel (3) falls to a first level (L2) below an upper level of the membranes; suspending the filtration operation; performing a liquid backwash of the membrane wall until liquid level within the feed-containing vessel (3) rises to a second predetermined level (L1) above said first level; aerating the membrane surface with gas bubbles to dislodge fouling materials therefrom; performing a sweep or drain down of the feed-containing vessel (3) to remove the liquid containing the dislodged contaminant matter

Abstract: Devices and methods are provided for determining the concentration of a reduced form of a redox species. For example, a device can include a working electrode and a counter electrode spaced by a predetermined distance so that reaction produces from the counter electrode arrive at the working electrode. An electric potential difference can be applied between the electrodes, and the potential of the working electrode can be selected such that the rate of electro-oxidation of the reduced form of the species is diffusion controlled. Current as a function of time can be determined, the magnitude of the steady state current can be estimated, and a value indicative of the diffusion coefficient and/or of the concentration of the reduced form of the species can be obtained from the change in current with time and the magnitude of the steady state current. Other embodiments of apparatuses, devices, and methods are also provided.

Abstract: A method and apparatus for reducing the effect of integrity loss in a hollow fiber membrane module, said module including a plurality of hollow fiber membranes (5), at least one end of the fiber membranes (5) being supported in a pot (6), the method including the step of increasing flow resistance of the liquid through the lumen (8) of the fiber membrane (5) in the region of the pot (6).

Abstract: A hollow electrochemical cell is provided. In one exemplary embodiment, a hollow electrochemical cell includes two sets of electrodes and an opening for admitting an analyte to the cell. At least one of the two sets of electrodes can be in fluid communication with the opening. Further, a first set of electrodes can include a working electrode spaced from a counter or counter/reference electrode by less than 500 ?m one embodiment the working and counter or counter/reference electrodes are not co-planer. In another embodiment the working and counter or counter/reference electrodes are of substantially corresponding area. In yet another embodiment the working and counter or counter/reference electrodes are spaced from 100 to 200 ?m apart. The first set of electrodes and the second set of electrodes can be spaced apart by greater than about 500 ?m. Other embodiments of a hollow electrochemical cell are also provided, as are several embodiments of a glucose sensor.

Abstract: A method for determining the concentration of a reduced or oxidized form of a redox species is provided. In one exemplary embodiment, an electrochemical apparatus is provided in which the apparatus includes a hollow electrochemical cell for measuring a concentration of glucose in a blood sample, a current of the cell is measured, and a concentration of a redox mediator is determined, at least in part from, a measured current of the cell. The hollow electrochemical cell can include at least one non-metal working electrode, at least one counter electrode or counter/reference electrode, and a spacer interposed between the working electrode and the counter or counter/reference electrode. In one embodiment the working electrode and the counter or counter/reference electrode are not co-planer and are separated by a distance of from about 20 microns to about 200 microns.

Abstract: A method of manufacture of an electrochemical cell is provided. In one exemplary embodiment, at least one non-metal working electrode is provided, at least one counter electrode or counter/reference electrode is provided such that it is not co-planer with respect to the working electrode, and a spacer is provided interposed between the working and counter or counter/referenced electrode. In one embodiment the counter or counter/reference electrode can be separated from the working electrode by a distance of from about 20 microns to about 200 microns. Alternatively, the cell can have an effective volume of less than 1.5 microliters. A method of manufacture of an electrochemical apparatus is also provided. The method can include providing both a hollow electrochemical cell for measuring a concentration of glucose in a blood sample and a mechanism configured to determine a concentration of a redox mediator from, at least in part, a measured current of the cell.

Abstract: A method for determining the concentration of a reduced or oxidized form of a redox species is provided. In one exemplary embodiment, an electrochemical apparatus is provided in which the apparatus includes a hollow electrochemical cell for measuring a concentration of glucose in a blood sample, a current of the cell is measured, and a concentration of a redox mediator is determined, at least in part from, a measured current of the cell. The hollow electrochemical cell can include at least one non-metal working electrode, at least one counter electrode or counter/reference electrode, and a spacer interposed between the working electrode and the counter or counter/reference electrode. In one embodiment the working electrode and the counter or counter/reference electrode are not co-planer and are separated by a distance of from about 20 microns to about 200 microns.

Abstract: A hollow electrochemical cell is provided. In one exemplary embodiment, a hollow electrochemical cell includes two sets of electrodes and an opening for admitting an analyte to the cell. At least one of the two sets of electrodes can be in fluid communication with the opening. Further, a first set of electrodes can include a working electrode spaced from a counter or counter/reference electrode by less than 500 ?m. In one embodiment the working and counter or counter/reference electrodes are not co-planer. In another embodiment the working and counter or counter/reference electrodes are of substantially corresponding area. In yet another embodiment the working and counter or counter/reference electrodes are spaced from 100 to 200 ?m apart. The first set of electrodes and the second set of electrodes can be spaced apart by greater than about 500 ?m. Other embodiments of a hollow electrochemical cell are also provided, as are several embodiments of a glucose sensor.

Abstract: A filtration system for removing fine solids from a liquid suspension comprising a vessel for containing the liquid suspension, one or more permeable, membranes (9) within the vessel, means for providing a pressure differential across walls of the membranes (9) such that some of the liquid suspension passes through the walls of the membranes (9) to be drawn off as permeate and means for withdrawing the permeate from the membranes. A screen (8) is positioned in a flow path of the liquid suspension through to the membrane walls.

Abstract: This invention relates to a biosensor and more particularly to an electrochemical biosensor for determining the concentration of an analyte in a carrier. The invention is particularly useful for determining the concentration of glucose in blood and is described herein with reference to that use but it should be understood that the invention is applicable to other analytic determinations.

Abstract: This invention relates to a biosensor and more particularly to an electrochemical biosensor for determining the concentration of an analyte in a carrier. The invention is particularly useful for determining the concentration of glucose in blood and is described herein with reference to that use but it should be understood that the invention is applicable to other analytic determinations.

Abstract: A membrane filtration module (5) of the type having a plurality of permeable, hollow membranes (6) mounted therein, wherein, in use, a pressure differential is applied across the walls of the permeable, hollow membranes (6) immersed in a liquid suspension containing suspended solids, said liquid suspension being applied to one surface of the permeable, hollow membranes (6) to induce and sustain filtration through the membrane walls wherein some of the liquid suspension passes through the walls of the membranes to be drawn off as clarified liquid or permeate, and at least some of the solids are retained on or in the permeable, hollow membranes (6) or otherwise as suspended solids within the liquid suspension, the module (5) including a fluid retaining means (13) at least partially surrounding the membrane module (5) for substantially retaining at least part of fluid flowed into the membrane module (5).