Electrochemical detection of hydrogen peroxide using an edge-plane pyrolytic-graphite electrode (EPPG), a glassy carbon (GC) electrode, and a silver nanoparticle-modified GC electrode is reported. It is shown, in phosphate buffer (0.05 mol L(-1), pH 7.4), that hydrogen peroxide cannot be detected directly on either the EPPG or GC electrodes. However, reduction can be facilitated by modification of the glassy-carbon surface with nanosized silver assemblies. The optimum conditions for modification of the GC electrode with silver nanoparticles were found to be deposition for 1 min at -0.5 V vs. Ag from 5 mmol L(-1) AgNO3/0.1 mol L(-1) TBAP/MeCN, followed by stripping for 2 min at +0.5 V vs. Ag in the same solution. A wave, due to the reduction of hydrogen peroxide on the silver nanoparticles is observed at -0.68 V vs. SCE. The limit of detection for this modified nanosilver electrode was 2.0 x 10(-6) mol L(-1) for hydrogen peroxide in phosphate buffer (0.05 mol L(-1), pH 7.4) with a sensitivity which is five times higher than that observed at a silver macro-electrode. Also observed is a shoulder on the voltammetric wave corresponding to the reduction of oxygen, which is produced by silver-catalysed chemical decomposition of hydrogen peroxide to water and oxygen then oxygen reduction at the surface of the glassy-carbon electrode.

Silver nanoparticle assemblies supported on glassy-carbon electrodes for the electro-analytical detection of hydrogen peroxide.

An interchangeable transducer for use with an ultrasound medical system having a keyless adaptor and capable of operating in a wet environment. The interchangeable transducer has an adaptor for engaging a medical system, an ultrasound transducer and additional electronics to provide a self-contained insert for easy replacement and usage in a variety of medical applications. A slip ring spacer is also disclosed, the slip ring spacer for use with a pancake slip ring having a base and flange configuration to form one or more channels around each contact ring of the pancake slip ring. The channels provide fluid isolation around each connector to help reduce electronic cross talk and contact corrosion between the connector pads of the slip ring while the slip ring is immersed in a wet environment.

Slip ring spacer and method for its use

Disclosed is a polycrystalline diamond or diamond-like element with greatly improved wear resistance without loss of impact strength. These elements are formed with a binder-catalyzing material in a high-temperature, high-pressure (HTHP) process. The PCD element has a body with a plurality of bonded diamond or diamond-like crystals forming a continuous diamond matrix that has a diamond volume density greater than 85%. Interstices among the diamond crystals form a continuous interstitial matrix containing a catalyzing material. The diamond matrix table is formed and integrally bonded with a metallic substrate containing the catalyzing material during the HTHP process. The diamond matrix body has a working surface, where a portion of the interstitial matrix in the body adjacent to the working surface is substantially free of the catalyzing material, and the remaining interstitial matrix contains the catalyzing material. Typically, less than about 70% of the body of the diamond matrix table is free of the catalyzing material.

High volume density polycrystalline diamond with working surfaces depleted of catalyzing material

A preform cutting element for a rotary drill bit includes a layer of polycrystalline diamond material, the rear face of which is bonded to the front face of a backing layer of less hard material, such as tungsten carbide. The rear face of the backing layer is substantially greater in area than the rear face of the diamond layer. A method of manufacturing such cutting elements comprises forming an intermediate structure comprising polycrystalline diamond material bonded between two outer layers of tungsten carbide, and then cutting the intermediate structure to provide two pieces, each of the pieces including part of the diamond material and at least a major part of a respective one of the two outer layers.

Cutting elements for rotary drill bits

The present invention provides a superhard polycrystalline diamond or diamond-like element with greatly improved resistance to thermal degradation without loss of impact strength. Collectively called PCD elements, these elements are formed with a binder-catalyzing material in a high-temperature, high-pressure process. The PCD element has a plurality of partially bonded diamond or diamond-like crystals forming at least one continuous diamond matrix, and the interstices among the diamond crystals forming at least one continuous interstitial matrix containing a catalyzing material. The element has a working surface and a body, where a portion of the interstitial matrix in the body adjacent to the working surface is substantially free of the catalyzing material, and the remaining interstitial matrix contains the catalyzing material. This translates to higher wear resistance in cutting applications, higher heat transfer capacity in heat sink applications, and has advantages in numerous other applications including hollow dies, indentors, tool mandrels, and wear elements.

Polycrystalline diamond partially depleted of catalyzing material

A sintered polycrystalline diamond compact having an integral metallic heat sink bonded to and covering at least the outer diamond surface is used to increase compact life when the compact is used for material removal without a fluid coolant.

Sintered polycrystalline diamond compact construction with integral heat sink

A method to fabricate a catheter tip that encapsulates a mechanically actuated ultrasound transducer assembly is provided. In a representative procedure, the steps include providing an ultrasound transducer assembly ( 100 ) adapted for use with a catheter ( 300 ), the ultrasound transducer assembly ( 100 ) comprising a proximal end ( 102 ) and a distal end ( 104 ), a drive linkage ( 132 ) to an actuator ( 130 ), and a transducer array ( 110 ), the transducer array ( 110 ) electrically connected to an interconnect ( 120 ) adapted for passage to or through a body of the catheter ( 300 ), connecting the actuator ( 130 ), adapted for use with the ultrasound transducer assembly ( 100 ), to the drive linkage ( 132 ); and inserting the ultrasound transducer assembly ( 100 ) and the actuator ( 132 ) into a polymer or a plastic type or reinforced polymer sheath ( 140 ) comprising an acoustically transparent section, a closed end ( 142 ) at its distal end and an open end ( 144 ) at its proximal end, wherein the polymer sheath ( 140 ) provides a defined rigidity.

Method of manufacture of catheter tips, including mechanically scanning ultrasound probe catheter tip, and apparatus made by the method

A device comprising an array of sensors built on or in a substrate with a semiconducting surface and means for isolating each sensor element from its neighbors. In the case where the sensors are ultrasonic transducer elements, acoustic isolation is provided in the form of trenches between neighboring transducer elements to reduce acoustic crosstalk. The trenches may be filled with acoustically attenuative material. Electrical isolation in the form of semiconductive junctions is provided between neighboring transducer elements to reduce electrical crosstalk. In one example, back-to-back pn junction diodes are formed by ion implantation in zones located between neighboring transducer elements. These types of isolation can be employed alone or together.

Method and means for isolating elements of a sensor array

An ultrasound system is provided for imaging an object. The ultrasound system includes an ultrasound probe for acquiring ultrasound data and a cooling subsystem for actively removing heat from the ultrasound probe. The cooling subsystem includes a pump disposed within a reservoir containing a coolant and configured to circulate the coolant through the ultrasound probe via a conduit.

System and method for actively cooling an ultrasound probe

A catheter tip (50, 170) is provided that is adapted for mating attachment to a catheter body (90, 300). In an embodiment, the catheter tip (50,170) comprises a transducer array (32, 60, 110, 210) in electrical communication with an interconnect (120, 220) and in a mechanical driven relationship with an actuator (80), also in the catheter tip (50, 170), via a drive shaft (38, 82). Oscillating back and forth motion of the transducer array (32, 60, 110, 210) provides ultrasonic imaging functionality that may include real time three-dimensional imaging. Other embodiments of the catheter tip (50, 170) and methods of fabrication also are provided.

George Charles Sogoian

Papers

Sintered polycrystalline diamond compact construction with integral heat sink

Method of manufacture of catheter tips, including mechanically scanning ultrasound probe catheter tip, and apparatus made by the method

Method and means for isolating elements of a sensor array

System and method for actively cooling an ultrasound probe

Apparatus for catheter tips, including mechanically scanning ultrasound probe catheter tip