A picture coding method includes the steps of translating the data of an image into 3-dimensional blocks and detecting their movements, in which the transform coefficients of a high degree in the space associated with the 3-dimensional blocks where more movement is involved are removed for reducing spatial resolution while maintaining time resolution and also, the transform coefficients of a high degree in the time associated with the 3-dimensional blocks where less movement is involved are removed for reducing time resolution while maintaining spatial resolution, so that the effective compression of the data can be implemented without a great visual degradation in the picture quality.

1. Field of the Invention
The present invention relates to a method of coding a picture signal with a high efficiency.
2. Description of the Prior Art
It is now known that the digital form of a picture signal can be transmitted at a speed of more than 100 Mbps and can hardly be carried cut through existing communication lines in the terms of transmittable amount and cost. Various picture coding methods and their apparatus have been introduced offering the techniques of eliminating the redundancy of picture signals and reducing the speed of signal transmission. One of them is an orthogonal transform coding apparatus which has widely been employed.
A prior art orthogonal transform apparatus will be described referring to the drawings.
It is understood that a natural image in which less movement is involved allows the horizontal and vertical and time base correlation between pixels to be higher and its corresponding transform coefficients are great in energy at the low sequence and small at the high sequence.
FIG. 8 is a block diagram showing a prior art 3-dimension orthogonal transform coding apparatus.
As shown in FIG. 8, there are provided an input buffer 81, an orthogonal transform block 82, a zonal sampling block 83, a 3-dimensional block activity estimation block 84, a 3-dimensional block classification block 85, a transform coefficient energy calculation block 86, a bit allocation calculation block 87, a normalization block 88, a transform coefficient quantization block 89, a multiplexer 810 and an output buffer 811.
An orthogonal transform coding method associated with the prior art orthogonal transform coding apparatus will is described below.
As shown in FIG. 8, the image data of K-frames are fed and stored in the input buffer 81. Then, they are read out in the form of M.times.M.times.K 3-dimensional blocks and orthogonally transformed by the orthogonal transform block 82. High sequence coefficients of the corresponding transform coefficients delivered from the orthogonal transform block 82 are blocked in three dimensions by the zonal sampling block 83 while the remaining low sequence coefficients are passed through. The transform coefficients passing the zonal sampling block 83 are transferred to the activity estimation block 84 where the activity in the image of the 3-dimensional block is calculated from: ##EQU1## where F(u, v, w) is a transform coefficient of the 3-dimensional block. The resultant activity values are then fed to the classification block 85 and separated into k-number of classes by the amount of energy of each 3-dimensional block. In each class of the 3-dimension blocks, the variance of the transform coefficient is calculated by the energy calculation block 86. From the resultant variance, the bit allocation in each class is then calculated by the bit allocation calculation block 87 for providing a bit map, using an equation expressed by: EQU N.sub.k (u,v,w)=1/2log.sub.2 [.sigma..sub.k.sup.2 (u,v,w)]-log.sub.2 [D] (u,v,w).noteq.(0,0,0)
where .sigma..sub.k.sup.2 (u, v, w) is a variance of the transform coefficient assigned to a k class and D is a parameter. Nk(u, v, w) can be determined for a desired speed of transmission by controlling the value of D. The bit allocation calculation block 87 delivers a coefficient for normalization in each class. The normalization coefficient may be a variance or the maximum value of a transform coefficient contained in the class. The transform coefficients from the orthogonal transform block 83 are also transferred to the normalization block 88 for normalization with the normalization coefficient and then, quantized by the quantizer 89 according to the bit allocation computed. The quantized output, the bit allocation map, and the class identifier are fed to the multiplexer 810 for coding and controlled in the transmission velocity by the output buffer 811 prior to delivery to the transmission line.
As described above, the high sequence coefficients associated with small energy and low visibility are removed by zonal sampling of the transform coefficients so that a signal compression with a reduced degradation of picture quality can be ensured. Also, the bit allocation corresponding to the energy of each block is made and thus, the compression will be possible considering the local properties of an image (for example, as disclosed in "Transform Coding of Images" by R. J. Clarke, issued by Academic Press in 1985).
However, according to the aforementioned arrangement, the high sequence coefficients are removed systematically and the picture quality of a particular image, e.g. a miniature image, which contains a large number of high sequence components will be reduced to a considerable degree. Also, the moving region of the image contains more time-base high sequence components of the 3-dimension orthogonal transform coefficients and less spatial high sequence components while the still image region contains less the former and more the latter. Accordingly, when the time-base high sequence components are removed, the active image will appear discontinuous in motion.
The bit allocation is determined by measuring the amount of energy not distinguishing between the moving and unmoving regions of the image and the bit allocation map will be established regardless of the distinct movements. As the result, the drawback is that the bit allocation is provided restricting the movement in the moving region and decreasing the resolution in the still region.

Highly efficient picture coding method with motion-adaptive zonal sampling enabling optimized image signal compression

Matsushita Electric Industrial Co., Ltd.


A method of managing memory mapped input/output (I/O) for a run-time environment is disclosed, in which opaque references are used for accessing information blocks included in files used in a dynamic run-time environment. The information block is stored in a shared memory space of pages that are each aligned on respective boundaries having addresses that are each some multiple of two raised to an integer power. The opaque reference used for the dynamic run-time environment includes at least an index, or page number reference into a page map of references to the pages of the shared memory space, and an offset value indicating an offset into the referenced page for the beginning of the storage of the information block. Control bits of the opaque reference indicate information such as the mapping mode, e.g., read-only, read-write, or private. Pages which are modified by a process may be written back to a backing store of the file based on control bits which indicate that a page has been modified.

A dynamic run-time environment for a language such as JAVA™ is responsible for managing memory used during execution of a program to store information. References are used by a run-time environment to identify and ultimately access regions of memory. For main memory in the address space of an executing program, these references are typically encoded using machine pointers. Since machine pointers are closely coupled to the underlying hardware and firmware of a computer system, machine pointers provide a fast means of accessing files and, hence, are a popular implementation for references. However, security may be jeopardized by exposing actual machine addresses of local data areas to the dynamic run-time environment for a language such as JAVA.
Many platforms have system library support for memory-mapped I/O, such as the UNIX function map( ), which establishes a mapping between the address space of a process and information stored in a file outside of the address space of the process (e.g. on disk or in another kind of secondary storage device). Successful use of the map( ) function provides an pointer containing a memory address to a region of main memory that corresponds to the mapped portion of the file. Memory-mapped I/O allows access to resources via address space manipulations, instead of through read and write operations, which reduces the processing time overhead compared to read and write access to a file. For example, a file on disk can be manipulated by memory mapping the file into virtual memory, modifying data in the region of the address space that has been mapped for the file via machine pointers, and storing the modified data back into secondary storage.
Differences between server environments make machine independence very difficult to achieve for portable run-time environments. For example, some operating systems, in practice if not by design, limit the guaranteed size of contiguous main memory to a "page," typically about two or four kilobytes in size, and prior paged memory systems simply failed when sufficient large blocks of virtual memory were not available. This page-size limitation may occur, for example, on computer systems that permit shared memory for access by different processes and even by different processors.
Another problem is that for safety reasons, some run-time environments do not permit applications to manipulated raw pointers directly. One example is a run-time environment for implementing JAVA™, an platform-independent, object-oriented language originally developed by Sun Microsystems, Inc. In JAVA, attributes and methods for a class of objects are typically defined in a source file, which is compiled into an architecture-neutral object file containing bytecodes that are interpreted in a virtual machine at the target platform. Because Java does not allow direct manipulation of memory for safety reasons, memory manipulations go through a call interface that dispatches to system native methods to perform the actual manipulation of main memory.
Therefore, a need exists for an efficient and safe memory-mapped I/O support for paged memory architectures.

Method and apparatus for memory-mapped input/output


A driving circuit for driving an electroluminescent lamp is disclosed. The driving circuit includes an alternating current (AC) voltage generator for providing at an output an AC output voltage waveform for driving an electroluminescent lamp and a controller for controlling the phase and polarity of the AC output voltage waveform. The controller is operable to reverse the phase and polarity of the AC output voltage. In one embodiment, the AC voltage generator includes a transformer.

Electroluminescent lamps, such as CCFLs, are used in a variety of applications, including illuminating liquid crystal displays, scanners, photocopiers and the like. The lamps themselves are small, relatively efficient and inexpensive. However, they must be driven by specialised driving circuits that are capable of providing an output voltage that is sufficiently high to ignite the lamp and sustain illumination of the lamp after ignition.
A block diagram for a conventional driving circuit 100 that is commonly used to drive a CCFL type electroluminescent lamp is depicted in FIG. 1. This driving circuit 100 includes an alternative current (AC) voltage source 102 and a transformer 104. The driving circuit 100 is shown here as connected to a CCFL 108 load.
In conventional driving circuits of the type illustrated in FIG. 1, the transformer 104 is typically connected to the AC voltage source 102 using a conventional push-pull type topology. In operation, the AC voltage source 102 alternately produces an input current in the primary windings 110, 112 of the transformer 104 so as to thereby generate an AC output voltage waveform 114 (in the form of a high voltage AC output waveform) at an output 116 of the driving circuit 100 for driving the electroluminescent lamp. As is illustrated, the generated. AC output voltage waveform 114 includes a positive half cycle 118 and a negative half cycle 120.
In conventional driving circuits of the type illustrated in FIG. 1, the direction of the winding current in each of the primary windings 110, 112 has a fixed direction. That is, the current alternately flows either from point A to points B and C, or otherwise, it alternately flows from points B and C to point A. Thus, the direction of these currents does not change during operation. Likewise, the relationship of the polarity and phase of the AC output voltage waveform to the primary windings will also not change; the positive half cycle will always be attributable to one of the primary windings, the negative half cycle will always be attributable to the other primary winding.
Although conventional driving circuits of the type shown in FIG. 1 operate satisfactorily, long term use may lead to a reduction in the usable life of the CCFL. Such a reduction tends to result as a consequence of the positive half cycle 118 and a negative half cycle 120 of the output voltage waveform 114 having a fixed relationship with the primary windings 110, 112. More specifically, and as a result of the above-described fixed relationship, if characteristics of the components used to supply the input voltage to the primary windings drift over time (or are not carefully matched), or indeed if the characteristics of the primary windings change, distortion of the output voltage waveform occurs. Such distortion typically results in an asymmetric AC output voltage waveform in which the peak magnitude of one half cycle is different (that is, greater or less than) to the peak magnitude of the other half cycle.
Asymmetry in the AC output voltage waveform tends to cause an uneven distribution of Mercury (Hg) within the CCFL in that the density of Hg at the end of the CCFL connected to the primary winding supplying the half cycle having the larger magnitude voltage will decrease over time. In a serious case, this will lead to blackening at one end of the CCFL tube and will adversely affect the performance of the devices using the CCFL (for example liquid crystal display, scanner, photocopier), even to the extent that such devices become unusable.
In view of the foregoing, it would be desirable to provide a driving circuit that solved the above-mentioned problems.

Electroluminescent lamp driving circuit and method


The present disclosure provides an image display method, an image processing method and related devices. The image display method includes: receiving and storing an original image from a processing terminal, the original image being an image rendered by the processing terminal; acquiring a first image from the original image; displaying the first image between a first time point and a second time point; acquiring a second image from the original image; and displaying the second image between the second time point and a third time point.

Along with the development of the network technology, currently there are many scenarios where image interaction needs to be performed between terminals. In a typical scenario, an image is rendered by a processing terminal, and then the rendered image is transmitted to a display terminal for display. However, in this technology, each image displayed by the display terminal needs to be rendered separately by the processing terminal and then transmitted separately, so the amount of rendering operations and transmission volume are relatively large for the processing terminal.

Image display method, image processing method and relevant devices

BEIJING BOE OPTOELECTRONICS TECHNOLOGY CO., LTD.


A rechargeable battery includes an electrode assembly; a case accommodating the electrode assembly; a cap plate coupled to an opening of the case; an electrode terminal connected to the electrode assembly and extending through a terminal hole of the cap plate; and a retainer having first ends contacting the case and located between the electrode assembly and the side wall to support the electrode assembly and the side wall, wherein a thickness of the retainer gradually decreases away from the first ends of the retainer.

1. Field
The described technology relates generally to a rechargeable battery assembled by vacuum sealing.
2. Description of the Related Art
A rechargeable battery differs from a primary battery in that it can be repeatedly charged and discharged, while the latter can only irreversibly convert chemical energy to electrical energy. A small sized rechargeable battery is used as a power supply for small electronic devices such as cellular phones, notebook computers, and camcorders, while a medium or large sized rechargeable battery is used as a power supply for driving motors in hybrid vehicles and electric vehicles.
Typically, a rechargeable battery includes an electrode assembly performing charging and discharging, a case receiving the electrode assembly, a cap plate coupled to an opening of the case, and an electrode terminal drawing the electrode assembly out to an outer side of the cap plate.
The rechargeable battery is assembled by being connected to the electrode assembly through the electrode terminal, installing the cap plate, inserting the electrode assembly into the case, and then welding the cap plate to the case.
After that, an inner space of the rechargeable battery is set to be vacuumed through an electrolyte injection opening formed in the cap plate during which a center portion of a wide side wall of the case may be deformed to be more concave compared to outer edge portions thereof.
Thus, the wide side wall of the case presses the electrode assembly and specifically, the center portion of the wide side wall may be subject to greater pressure compared to the outer edge portions. In other words, the electrode assembly may be non-uniformly pressed with respect to the side wall so that the electrode assembly may be prevented from uniformly charging and discharging depending on a location corresponding to the wide side wall of the case.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the described technology and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.


The present invention is directed to an anti-cancer drug containing an anti-MFG-E8 antibody as an active ingredient, and to an anti-cancer drug which employs an anti-MFG-E8 antibody in combination with a cancer therapy employing an anti-cancer agent other than the anti-MFG-E8 antibody.

In 1981, cancer has become the leading cause of death in Japan, and has remained the leading cause of death since then. Thus, there is continuous demand for novel cancer therapy. Currently employed cancer therapies include surgical therapy, radiotherapy, and chemotherapy (by means of anti-cancer agents). Even after surgical operation, a cancer therapy by an anti-cancer agent is also employed.
Examples of anti-cancer agents currently employed include an alkylating agent, a metabolic antagonist, an alkaloid anti-cancer agent, an antibiotic anti-cancer agent, and a platinum drug. However, the therapeutic effects of the anti-cancer agents are not sufficient at present, and adverse side effects often arise, which are problematic. From this viewpoint, development of a more improved anti-cancer agent is envisaged.
Meanwhile, MFG-E8 (a milk fat globule membrane glycoprotein: milk fat globule-EGF factor 8) was previously identified as a factor which is secreted through the mammary gland and which promotes differentiation of the mammary gland and suckling stimulation (Non-Patent Document 1). In recent years, in addition to the above actions, MFG-E8 has been found to have a variety of functions. Among them, one important function thereof is that MFG-E8 serves as an opsonin which recognizes phosphatidylserine present on the surfaces of apoptotic cells, to thereby promote the phagocytic activity of macrophages and dendritic cells, whereby immune tolerance is maintained (Non-Patent Documents 2, 3). Furthermore, MFG-E8 is known to promote growth of Foxp 3-positive-regulatory T cells, to thereby induce tolerance, whereby the antitumor immunity of an anti-tumor vaccine is negatively controlled (Non-Patent Document 4). On the basis of these findings, a therapeutic method employing a decoy gene of MFG-E8 and an anti-MFG-E8 antibody were previously developed with the aim of combined use with a tumor antigen such as a cancer vaccine, and a patent application was filed (Patent Document 1). Also, studies revealed that MFG-E8 is widely expressed not only in antigen-presenting cells such as dendritic cells but also in cells of a tumor (e.g., breast cancer, colon carcinoma, or melanoma) (Non-Patent Document 5), and that MFG-E8 has a tumor-activating action through promoting angiogenesis and tumor metastasis and positively correlates with the clinical progress of melanoma (Non-Patent Document 6).


The coupling of an electret microphone is detected and identifying whether there is monaural or stereo speakers coupled to the USB connector is accomplished by coupling a current source to the USB ID terminal and detecting the voltage on the ID terminal. If the voltage on the ID line is substantially below the voltage associated with any other accessory when an electret microphone is coupled between the ID terminal and the ground terminal, and a microphone bias resistor is coupled to the ID line. On detection of an electret microphone being coupled between the ID terminal and the ground terminal, whether there is a monaural or stereo speakers coupled to the USB connector is determined by detecting the impedance on the one of the D+ and D− terminals to which a monaural speaker would not be coupled. An open circuit indicates a monaural speaker, otherwise stereo speakers are connected. An alternate embodiment is disclosed.

1. Field of the Invention
The present invention relates to the field of cell phones and other portable equipment using a USB bus connector.
2. Prior Art
The USB bus has five bus connections, namely VBUS (power), two data lines D+ and D—, an ID (identification) line and ground. In a cell phone application using a MiniB or micro-B USB connector on the phone, an accessory connected to the connector may be identified by the phone by checking the value of a resistor coupled between the ID line and ground line in the accessory. In that regard, there is a published specification CEA-936A describing the use of a Mini-B or Micro-B USB connection for other accessories, but it only allows 2 wires (D+ and D− data lines) for signals. Consequently a Mini-B or Micro-B USB connection in accordance with CEA-936 A specification cannot accommodate the combination of a microphone and a stereo headset.
A typical microphone detection circuit detects the bias voltage of the attached microphone. As shown in FIG. 1, a comparator is used to check the voltage across the microphone JFET preamplifier with a typical 2.2K pull up resistor. This pulls the ID line to the supply voltage when a microphone is not connected. With a microphone connected, the voltage across the microphone is about 1.18 volts, and the output of the comparator changes state due to the inverting input being biased at 2.27 volts. However the bias voltage of the microphone varies due to JFET characteristics and makes reusing the microphone connection for detecting other accessories difficult and unreliable.

Electret microphone detection using a current source


A debugging tool for computer program development that analyzes the computer program adds output statements at strategic locations throughout the program. The output statements may include the filename and line number of the original source code and may further include a listing of the executed command as well as values of certain expressions and/or variables as defined by the requested verbosity. The verbosity may be set at different levels throughout the source code as required.

a. Field of the Invention
The present invention pertains to computer program development tools and specifically to automated tools for facilitating debugging of computer programs.
b. Description of the Background
Testing and debugging computer code is typically a large portion of the development cycle of a computer program. Several program development environments are specifically constructed to aid a developer in the writing, editing, testing and debugging of code by enabling the developer to step into and through the code, evaluate variable values, etc. Such development environments are not always available to those developers whose applications are not supported by the environments.
It is commonplace for software developers to insert print statements at periodic intervals throughout their program so that the state of the program may be monitored when the program is run. These print statements are time consuming to write and may require a working knowledge of the function of the code to place the statements in the proper locations.
It would therefore be advantageous to provide a system and method for automatically placing debugging statements into a program that may enable a tester or developer to efficiently trace the flow of the program and help in debugging the program. It would be additionally advantageous if such a system and method were adaptable to different depths of debugging and different debugging techniques.

Debugging with set verbosity level during read and analysis of executable code and associated comments while logging according to set verbosity level


The present invention provides a cationic group-containing amphiphilic block copolymer that is biocompatible and biodegradable, and when used as a drug carrier for an anionic drug, provides several advantages, such as increased blood concentration and improved stability of the drug.

1. Field of the Invention
The present invention relates to a positively charged drug carrier which forms a complex with a negatively charged drug. More specifically, the present invention relates to a positively charged polymeric micelle type drug carrier which comprises an A-B block type copolymer wherein A is a hydrophilic polymer block and B is a hydrophobic biodegradable polymer block and wherein one end of the hydrophobic polymer block (B) is covalently bound to one cationic group. The positively charged biodegradable block copolymer of the present invention forms a complex with a negatively charged drug via electrostatic interactions. The cationic copolymers of the present invention can be used in drug delivery and are especially useful for delivery of anionic bioactive agents.
2. Related Art
Biodegradable polymers are gaining attention as drug delivery systems. R. Langer, New Methods of Drug Delivery, 249 Science 1527–1533 (1990); B. Jeong et al., Biodegradable Block Copolymers as Injectable Drug-delivery Systems, 388 Nature 860–862 (1997). Delivering bioactive agents from biodegradable delivery systems is very desirable because the need for surgery to remove the delivery system is avoided. Controlled release of bioactive agents can reduce the required frequency of administration by maintaining adequate concentration of the therapeutic agent. One important means of maintaining a proper concentration is to control the degradation rate of the biodegradable drug delivery system.
The biodegradable hydrophobic polymers that are widely used as drug carriers include polylactic acid (PLA), polyglycolic acid (PGA), a copolymer of lactic acid and glycolic acid (PLGA), polycaprolactone (PCL), polyorthoester (POE), polyamino acid (PAA), polyanhydride (PAH), polyphosphazine, polyhydroxybutyric acid (PHB), polydioxanone (PDO), etc. Such polymers have good biocompatibility and the desirable feature of being hydrolyzed and decomposed in a living body to give side products which have no toxicity. For these reasons, they are widely used as drug carriers. In particular, since these polymers are insoluble in water formulations, some drugs can be incorporated into the polymer matrix and then implanted in the body in the form of microspheres, nanospheres, films, sheets, or rods, whereby the drug is slowly released exerting a sustained therapeutic effect. In these types of formulations, the polymers themselves are finally decomposed in the body. However, these polymers have low affinity for water-soluble drugs making it very difficult to incorporate a large amount of drug into the polymer matrix. Even if the drug is effectively incorporated into the polymer matrix, the problem of an initial burst release (referring to the phenomenon whereby a large amount of drug is released within the first few hours) may occur after implantation into the body.
A-B, B-A-B, or A-B-A type block copolymers, wherein A is a hydrophilic polymer block and B is a hydrophobic biodegradable polymer block, have been used as drug carriers for the delivery of physiologically active materials in the form of polymeric micelles, nanospheres, microspheres, gels, etc. These block copolymers have desirable properties such as good biocompatibility and the ability to form core-shell type polymeric micelles in aqueous solutions where the core is composed of hydrophobic blocks and the shell is composed of hydrophilic blocks. Micellar formulations, wherein a poorly water soluble drug can be incorporated into the inside of polymeric micelle to give a micellar solution, are good drug carriers for hydrophobic drugs. However, since the drug is incorporated via hydrophobic interaction between the hydrophobic drugs and hydrophobic polymer, the incorporation efficiency of highly hydrophobic drugs is excellent, but water-soluble hydrophilic drugs are poorly incorporated into those polymeric micelles.
Kataoka et al. (EP 721,776 A1) have developed a method for incorporating a charged water-soluble drug into the inside of a polymeric micelle using a block copolymer consisting of a non-charged block and a charged block. The charged block used by Kataoka is a polyamino acid having an ionic side chain, such as polyaspartic acid, polyglutamic acid, polylysine, polyarginine, or polyhistidine. However, they are not biodegradable in a living body. In addition, since the charged block may include several functional groups having electric charges, when they are combined inside the microsphere via electrostatic binding with a drug having multiple ionic groups, such as peptides or proteins, they may decrease the stability of such drugs.
In view of the foregoing, development of a drug carrier for anionic drug delivery that is biocompatible and biodegradable will be appreciated and desired. Thus, the present invention provides a new type of positively charged amphiphilic block copolymer that is biocompatible and biodegradable and that can effectively deliver the drug without a decrease in its stability. By forming a complex with an anionic drug via electrostatic interaction, the cationic amphiphilic block copolymer of the present invention can effectively incorporate a water-soluble negatively charged drug into the amphiphilic block copolymer. In addition, the block copolymer of the present invention is readily susceptible to metabolic degradation after incorporation and delivery of the drug into the cell.

Positively charged amphiphilic block copolymer as drug carrier and complex thereof with negatively charged drug


Systems and methods for implementing per-session load balancing of packets that increase traffic sharing and reduce systematic unequal distribution of traffic are provided by virtue of one embodiment of the present invention. A method for operating a selected router is provided that uses a load balancing algorithm that is configured to de-correlate distribution of sessions among the active paths at the selected router relative to distributions of sessions of other algorithms at other routers of said network. Packets arriving at the selected router are assigned to an output path according to the load balancing algorithm. A method of routing a packet received at a router having an associated identifier is provided. The source address and a destination address of the packet are obtained. An output path is selected according to a load balancing algorithm that uses the associated identifier, the source address, and the destination address as inputs, and the packet is routed to the output interface associated with the selected output path. A look-up table that is configured using the identifier can be used in selecting the output path. A router storing an identifier assigned to the router is provided; the identifier is used in determining per-session routing of incoming packets.

The present invention relates to routing in a packet switched network. In particular, it relates to methods of performing session load balancing and reducing polarization effects. In a packet switched network, each incoming packet at a router is sent to an output path, with the choice of output path made based on information at the router. (Where a packet has multiple destinations, it can be routed to multiple output paths.) A divergent network is one in which there are multiple paths going through different routers for at least one source-destination pair.
A packet is said to belong to a session. A session is a unidirectional end-to-end IP communication between two IP nodes. All packets in a session have the same source IP address and the same destination IP address.
A destination IP prefix is a leading part of the destination IP address, typically denoting the network address; e.g., IP address 198.01.01.01 can have a destination IP prefix of 198.01. Destination IP prefixes are commonly used to make routing decisions, as known in the art of routing. For example, a table may be maintained showing possible output paths by destination IP prefix.
At a router, an active path for a packet is a valid route to reach the destination address of the packet, that is deemed to have an acceptable cost, as known in the art of routing. A path can be specified in terms of a next-hop IP address and output interface, as known in the art of routing. Load balancing at a router can be thought of as the ability to share the traffic to a destination IP prefix over all active paths. In this application below, the terms "path" and "active path" are used interchangeably.
It is known to achieve near-perfect traffic sharing using per packet routing, where a round-robin based scheme can be used to load balance each packet, and packets in the same session can follow different paths. However, this can result in packet reordering and non-predictive latency for a session, which are undesirable for some applications. Per session load balancing largely eliminates these disadvantages, as known in the art.
In per session load balancing, all packets from a session take the same path from source to destination. Load balancing at a router is the ability to share the traffic to a destination prefix over all the output paths of a router. That is, for a given destination IP address, load sharing can be implemented by having the same number of sessions assigned to each path active for that destination. In a router one or more active paths to a given destination IP prefix may be assigned to an output interface of that router.
In per session load balancing, packets belonging to a session that arrive at a router must consistently be routed to the path. It is known to accomplish this via a hash function that depends only on the source address and destination address for a given number of active paths, and therefore always gives the same result for a given source and destination pair ("(S,D) pair"). The result is called the hash bin or hash result. The hash bin is mapped to a path. In prior art routers, the same hash function is used in each router of a given model and/or manufacturer of router, as described below.
The hash function is designed to evenly distribute the possible (S,D) pairs among the hash bins. For example, typically there can be 16 hash bins with values that are integers between 0 and 15, inclusive. If there are two paths, 8 of the hash bins will be assigned to the first path and 8 hash bins to the second path. This is typically accomplished by assigning even hash bins, i.e. hash bins in the set {0, 2, 4, 6, 8, 10, 12, 14}, to the first path and odd hash bins to the second path, or vice versa. It is known to achieve uneven load sharing by assigning hash bins proportionally; for example, 3:1 load sharing between two paths can be accomplished by assigning 12 hash bins to one path and 4 hash bins to the second path.
Packet routing is by nature decentralized because packets are routed to a next-hop upon arrival at a router. Fast performance is needed because of increasing network traffic and demands for faster response time. Although prior systems are decentralized and fast, a problem is that systems including such routers implementing per session load balancing are observed to exhibit systematically unequal distribution of load sharing. This is a problem among other reasons because links are not used efficiently.
Accordingly, it would be desirable to perform fast session load balancing that reduces systematic load imbalances presently observed. It would further be desirable if the system were decentralized and fine adjustments in load sharing could easily be achieved without reconfiguring the network topology.

Method and apparatus for per session load balancing with improved load sharing in a packet switched network


The present invention relates to isolated polypeptides having lysophospholipase activity and isolated nucleic acid sequences encoding the polypeptides. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the nucleic acid sequences as well as methods for producing and using the polypeptides.

1. Field of the Invention
The present invention relates to isolated polypeptides having lysophospholipase activity and isolated nucleic acid sequences encoding the polypeptides. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the nucleic acid sequences as well as methods for producing and using the polypeptides.
2. Description of the Related Art
Phospholipases are enzymes that participate in the hydrolysis of phospholipids which consist of a glycerol backbone with two fatty acids in an outer (sn-1) and the middle (sn-2) positions and esterified with phosphoric acid in the third position. The phosphoric acid may, in turn, be esterified to an amino alcohol.
Several types of phospholipase activity can be distinguished which hydrolyze the fatty acyl moieties. Phospholipase A1 and A2 catalyze the deacylation of one fatty acyl group in the sn-1 and sn-2 positions, respectively, from a diacylglycerophospholipid to produce lysophospholipid. Lysophospholipase (also called phospholipase B by the Nomenclature Committee of the International Union of Biochemistry on the Nomenclature and Classification of Enzymes {Enzyme Nomenclature, Academic Press, New York, 1992}) catalyzes the hydrolysis of the remaining fatty acyl group in a lysophospholipid. A phospholipase B has been reported from Penicillium notatum (Saito et al., 1991, Methods in Enzymology 197:446-456) which catalyzes the deacylation of both fatty acids from a diacylglycerophospholipid and intrinsicly possesses lysophospholipase activity.
Fungal enzymes with phospholipase activity have been reported from various sources, including Cryptococcus neoformans (Chen et al., Infection and Immunity 65: 405-411), Fusobacterium necrophorum (Fifis et al., 1996, Veterinary Microbiology 49: 219-233), Penicillium notatum (also known as Penicillium chrysogenum; Kawasaki, 1975, Journal of Biochemistry 77: 1233-1244; Masuda et al., 1991, European Journal of Biochemistry 202: 783-787), Penicillium cyclopium (Mustranta et al., 1995, Process Biochemistry 30: 393-401), Saccharomyces cerevisia (achimasa et al., 1985, Agric. Biol. Chem. 49: 1083-1089; Paultauf et al., 1994, Journal of Biological Chemistry 269: 19725-19730), Torulaspora delbrueckii (old name Saccharomyces rosei, Kuwabara, 1988, Agric. Biol. Chem. 52: 2451-2458; Watanabe et al., 1994, FEMS Microbiological Letters 124: 29-34), Schizosaccharomyces pombe (Oishi et al., 1996, Biosci. Biotech. Biochem. 60: 1087-1092), Neurospora crassa (Chakravarti et al., 1981, Archives of Biochemistry and Biophysics 206: 393-402), Aspergillus niger (Technical Bulletin, G-zyme(trademark) G6999, Enzyme Bio-Systems Ltd.; Mustranta et al., 1995, supra), Corticium centrifugum (Uehara et al., 1979, Agric. Biol. Chem. 43: 517-525), Fusarium oxysporum (WO 98/26057), and Fusarium solani (Tsung-Che et al., 1968, Phytopathological Notes 58:1437-38).
Fungal phospholipase genes have been cloned from several sources including Penicillum notatum (Masuda et al., 1991, supra), Torulaspora delbrueckii (Watanabe et al., 1994, FEMS Microbiology Letters 124: 29-34), Saccharomyces cerevisiae (Lee at al., 1994, Journal of Biological Chemistry 269: 19725-19730), Aspergillus (JP 10155493), Neurospora crassa (EMBL O42791), and Schizosaccharomyces pombe (EMBL O13857).
It is an object of the present invention to provide improved polypeptides having lysophospholipase activity and nucleic acid encoding the polypeptides.
The present invention relates to isolated polypeptides having lysophospholipase activity selected from the group consisting of:
(a) a polypeptide having an amino acid sequence which has at least 65% identity with amino acids 38 to 654 of SEQ ID NO. 2 or amino acids 17 to 648 of SEQ ID NO. 16;
(b) a polypeptide encoded by a nucleic acid sequence which hybridizes under high stringency conditions with (i) nucleotides 214 to 2061 of SEQ ID NO. 1 or nucleotides 49 to 1944 of SEQ ID NO. 15; (ii) the genomic DNA sequence containing nucleotides 214 to 2061 of SEQ ID NO. 1 or nucleotides 49 to 1944 of SEQ ID NO. 15; (iii) a subsequence of (i) or (ii) of at least 100 nucleotides; or (iv) a complementary strand of (i), (ii), or (iii);
(c) an allelic variant of (a) or (b); and
(d) a fragment of (a), (b) or (c), wherein the fragment has lysophospholipase activity.
The present invention also relates to isolated nucleic acid sequences encoding the polypeptides and to nucleic acid constructs, vectors, and host cells comprising the nucleic acid sequences as well as methods for producing lypeptides.

Polypeptides having lysophospholipase activity and nucleic acids encoding same


In one embodiment, a material includes at least one metal compound incorporated into a polymeric matrix, where the metal compound includes a metal and one or more carboxylate ligands, where at least one of the one or more carboxylate ligands includes a tertiary butyl group, and where the material is optically transparent. In another embodiment, a method includes: processing pulse traces corresponding to light pulses from a scintillator material; and outputting a result of the processing, where the scintillator material comprises at least one metal compound incorporated into a polymeric matrix, the at least one metal compound including a metal and one or more carboxylate ligands, where at least one of the one or more carboxylate ligands has a tertiary butyl group, and where the scintillator material is optically transparent and has an energy resolution at 662 keV of less than about 20%.

Radioactive materials are often detected and identified by measuring gamma-rays and/or neutrons emitted from the materials. The energy of gamma-rays is specific to that particular material and acts as a "finger print" to identify the material. Similarly, neutron emissions may be used to identify the material. Of high value are detectors capable of identifying the distinctive time-correlated signatures corresponding to neutrons and gamma rays, or "gammas" emitted by fissioning material from within a background of uncorrelated natural radiation. A detector capable of distinguishing neutrons from gammas, as well as offering a fast response time typically has better capability for detecting the distinctive time-correlated events indicative of the presence of fissioning nuclei.
The ability to detect gamma rays and/or neutrons is a vital tool for many areas of research. For example, gamma-ray/neutron detectors allow scientists to study celestial phenomena and diagnose medical diseases. Neutron imaging is used in non-destructive evaluation of complex objects. Additionally, gamma and neutron detectors are important tools for homeland security, helping the nation confront new security challenges. The nuclear non-proliferation mission requires detectors capable of identifying diversion or smuggling of nuclear materials. Government agencies need detectors for scenarios in which a terrorist might use radioactive materials to fashion a destructive device targeted against civilians, structures, or national events. To better detect and prevent nuclear incidents, the Department of Energy (DOE) and the Department of Homeland Security (DHS) are funding projects to develop a suite of detection systems that can search for radioactive sources in different environments.
One particularly useful type of radiation detection, pulse shape discrimination (PSD) provides means for high-energy neutron detection in the presence of gamma radiation background by utilizing the difference in the shapes of scintillation pulses excited by neutrons (recoil protons) and gamma (γ)-rays in organic scintillators. PSD phenomena in organic scintillators are based on the existence of multiple components in the fluorescent decay. In addition to the principal prompt component decaying exponentially (prompt fluorescence), slower emission components with longer decay times (delayed emission) exhibit increased amplitudes for neutron scintillation events, compared to gamma scintillation events. According to a commonly accepted mechanism shown in FIG. 1, the fast component results from the direct radiative de-excitation of excited singlet states (S1), while the slow component originates from the collisional interaction of pairs of molecules (or excitons) in the lowest excited it-triplet states (T1).
Since the triplet is known to be mobile in some compounds, the energy migrates until the collision of two triplets collide and experience a process, shown as Equation 1:T1+T1→S0+S1  Equation 1
In Equation 1, T1 is a triplet, S0 is the ground state, and S1 is a first excited state. Finally, the delayed singlet emission occurs with a decay rate characteristic of the migration rate and concentration of the triplet population, and is represented by Equation 2:S1→S0+hv  Equation 2
In Equation 2, hv is fluorescence, while S0 is the ground state and S1 is a first excited state. The lifetime of the delayed emission is determined by the lifetime of T1 and the rate of T1T1 collisions. The short range of the energetic protons produced from neutron collisions yields a high concentration of triplets, compared to the longer range of the electrons from the gamma interactions, leading to the enhanced level of delayed emission with longer decay times in neutron-induced pulses in comparison to those produced by the gamma excitation. The observation of PSD in organics with phenyl groups is believed to be, in part, related to the aromatic ring structure, allowing for the migration of triplet energy.
FIG. 2A shows a plot of average waveforms for a stilbene test crystal indicating different levels of delayed light in neutron and gamma scintillation pulses. As can be seen from the plot, some light is produced by the crystal almost immediately, referred to as prompt light, and other light is produced by the crystal over a period of time, referred to as delayed light. Generally, the plot for each type of radiation will have a steep component 202 and a tail component 204. The upper line in the plot represents neutron light decay, while the lower line represents gamma (γ) light decay. As shown in FIG. 2A, the shape for the neutron response has a large tail component 204, which is much smaller or almost negligible for gammas. Thus, stilbene is able to differentiate between the neutron and gamma light decays, and produces noticeably different lines for each radiation type. Unfortunately, growth of stilbene single crystals is difficult and costly, and the crystals are fragile and extremely sensitive to thermal and mechanical shock, making them difficult to field and creating demand for plastic-based alternatives.
Modern waveform digitizers allow for easy separation of neutron and gamma pulses, enabling instrumentation of PSD scintillators into fieldable detectors, as shown in FIG. 2B. The waveforms may be numerically integrated over two time intervals: ΔTotal and a subinterval ΔTail (e.g., for >50 ns), corresponding to the total charge and the delayed component of the signal, respectively. The value of the ratio of charge R=QTail/QTotal for the two time intervals indicates whether the considered event was likely produced by a neutron (high R value) or a gamma ray (small R value). The plot shown in FIG. 2B reveals the presence of both neutrons (upper scatter points) and gammas (lower scatter points) in a plot of the ratio of charge (QTail/QTotal) versus the pulse height.
FIG. 2C illustrates one approach where the neutron/gamma delayed light separation, S, in the stilbene test crystal is used for calculation of the PSD figure of merit (FOM). The PSD separation, S, refers to the gap between the mean ratio of charge (QTail/QTotal) for gamma rays and the mean ratio of charge (QTail/QTotal) for neutrons taken over an extended period of time. The larger the separation, S, the better the organic crystal is at PSD for distinguishing gammas and neutrons.
The PSD technique is most frequently utilized for discrimination between fast neutrons (recoil protons) and gamma-rays (Compton electrons) using liquid scintillators and a few organic crystals. Recent developments broadened the group of PSD materials to include scintillating plastics.
Plastic scintillators are radiation detectors with multiple fields of use that may be easily and inexpensively manufactured in different configurations and sizes. However, being comprised of materials with a low effective atomic number (Zeff), hydrocarbon-based plastics exhibit inefficient photoelectric absorption and are thus rarely used to detect gamma radiation. The photoelectric cross section scales as Zeff4. Accordingly, in one approach, a high Z component may be added to a plastic scintillator to increase photoelectric absorption and sensitivity to gamma radiation. One disadvantage with this approach is the reduction in light yield with increasing concentration of the high Z component. This reduction in light yield associated with high Z loaded plastic scintillators is thought to arise from the conversion of singlet excitons to triplet excitons via spin-orbit coupling to the high Z component. The resulting triplet excitons may not be collected by an emitting dye, or fluor present in the plastic scintillator, which is typically a singlet emitter, thereby diminishing the luminescence light yield of the plastic scintillator. It has also been found in some approaches that adding an effective amount of a high Z component in a plastic scintillator to enhance photoelectric absorption has resulted in a yellowing or browning of the plastic scintillator, thus yielding insufficient optical clarity in the scintillating wavelength region.
Moreover, as plastic scintillators are typically comprised of mostly hydrocarbons, such plastic scintillators are unable to detect the large fraction of low-energy (thermal neutrons) that do not generate enough light in elastic scatter interactions. In addition to neutron detectors, neutron imagers based on lens-coupled scintillator screens typically use standard plastic scintillators. For these and other neutron detection systems employed to register neutrons throughout the energy range from multiple MeV down to thermal, employ only proton recoils, which produce relatively low light yields, rendering this approach of minimal value once the neutrons have insufficient energy to produce a detectable signal. For these applications, introduction of a neutron capture agent, such as Lithium, provides a strong signal for thermal neutron detection.
Present techniques for detection of thermal neutrons are typically based on 3He detectors. However, due to the imminent shortage of 3He, other neutron detection technologies utilizing 10B- and 6Li-loaded scintillating materials have been considered as possible replacements for 3He detectors. The neutron detection properties of 10B- and 6Li-containing scintillators are based on known capture reactions:10B+no=7Li+α+2.79 MeV6Li+no=3He+α+4.78 MeV.
Current scintillators utilizing the thermal neutron detection capabilities of 10B generally use boron in a gaseous form, as BF3, or in a solid form consisting of pure boron or a compound mixture (e.g. boron carbide) present in a matrix. Moreover, current scintillators utilizing the thermal neutron detection capabilities of 6Li include inorganic single crystals (e.g. LiI, LiF, Li-aluminate, Cs2LiYCl6:Ce (CLYC), 6Li-lanthanide borate, etc.), 6Li-loaded glass scintillators, and composite materials including dispersions of nano- or micro-particles of different Li-containing compounds (e.g. nano- or microscale Li-containing crystals) in liquid or plastic matrices.
However, there are several disadvantages associated with existing 10B and 6Li based detectors. For example, single crystal detectors are limited by the size of the crystals that can be grown and the high cost of doing so. Additionally, difficulties that may arise from use of 6Li-loaded and/or 10B-loaded glass scintillators include long decay times and high sensitivity to gamma rays due to the presence of relatively high-Z constituents in their compositions.
Drawbacks with composite materials comprising dispersions of nano- or micro-particles of scintillating compounds in polymer and/or liquid matrices includes elevated levels of light scatter due to inhomogeneous composition and structure, as well as limitations in effective neutron detecting due to insufficient optical clarity in the scintillating wavelength region. Moreover, the lack of solubility of highly polar Li-containing compounds in on-polar aromatic matrices needed for efficient scintillation is another obstacle preventing the use of 6Li-loaded plastic scintillators. While 10B-containing compounds, such as ortho- and meta-carboranes, may be easily introduced into the composition of plastic scintillators, the fabrication of such detectors may be cost prohibitive due to the high expense associated with isotopical enrichment of carboranes from ˜19% of 10B in natural abundance to over 90% needed for the neutron capture probability.
An additional detector design allowing both gamma spectroscopy and neutron detection employs a Bismuth loaded plastic with a surface coating of a 6Li-loaded phosphor. It should be noted that the large volume of the plastic scintillator with high concentration of protons is an effective neutron thermalization medium. This type of detector, known as a "phoswitch," employs PSD to distinguish between events exhibiting the decay time of the plastic scintillator (from gamma interactions), typically ˜1 ns, and neutron capture events in the 6Li-loaded phosphor, which exhibit the characteristic decay time of the phosphor, typically in the 100-1000 ns range. In this way, a single, low-cost, large-volume plastic scintillator detector, utilizing a single Photomultiplier Tube (PMT) for readout, can provide both gamma spectroscopy and neutron detection.

Plastic scintillators with high loading of one or more metal carboxylates

Lawrence Livermore National Security, LLC


A nausea control device which provides electrical stimulation to the K9 acupressure point or points on the finger of a patient. Various mounting structures may be used to hold the electrodes in place over the K9 point, and hold the pulse generation circuitry and power supply in convenient location relative to the electrodes and the patient.

Woodside Biomedical, Inc. currently markets a wrist-borne nausea control device under the trademark RELIEFBAND®. The device is effective in alleviating the nauseous symptoms of motion sickness, morning sickness, anesthesia drugs and chemotherapy drugs. The device applies pulses of electrical stimulation to a specific point on the wrist, referred to as the P6 acupuncture point. The treatment provided by the device is sometimes referred to as electro-acupuncture, which is a form of acupuncture, and the ventral site of application is referred to in the acupuncture art as the P6 point, pericardium 6 point, or master point of the pericardium meridian (sometimes referred to as the vascular meridian). It is also portable, self-contained and convenient to the patient. Electrical pulse repetition rate of approximately 70 pulses per second and a pulse width of 80 microseconds have been found to provide effective relief of nausea in a patient. Our currently preferred electrical pulse pattern comprises about 350 microsecond pulse width at about 31 pulses per second at power levels of about 10–35 milliamps peak pulse height. Thus a wide range of pulse patterns may be used in non-invasive nerve stimulation devices.
Recently, the K9 Korean acupressure point has been identified as a point that may be manually stimulated to relieve post-operative nausea. Initial testing of electrical stimulation of the K-9 acupressure point indicates that it will alleviate nausea.

Device and method for nausea suppression


A system and method for automatically generating a video specific to a contact for display on a mobile telephone when a call is initiated with the contact. Media files are manually and/or automatically associated with an individual contact, and a video generator module automatically creates a theme video based upon the associated media files. When a call is made to or from the contact, the video is played on the mobile telephone or other electronic device.

In recent years, the number of features that have been incorporated into devices such as mobile telephones has increased exponentially. With increases in memory and processing capabilities in mobile devices, manufactures have been able to greatly increase the number of features on such devices, permitting users to greatly customize their own products.
One such area where users have been provided with increased customizable options involves the multimedia experience associated with initiating and receiving telephone calls. Many mobile telephones indicate the arrival of an incoming call with a customizable ring tone, which can take the form of a MIDI, .wav, MP3 or adaptive audio coding (AAC) music file. Some systems permit a user to change the ring tone for different individuals, providing an indication of who has placed a call. Other systems enable users to literally create their own ring tones. Traditionally, many users have also been able to observe basic information about another party on an actual or attempted telephone call. For example, a user is often able to see the name and telephone number of a person to whom a call is being made or of the person who is initiating such a call.
In recent years, additional pieces of information have started to become available to call initiators and recipients. For example, U.S. Published Patent Application No. 2003/0139172 and U.S. Pat. No. 6,757,533, both of which filed Jan. 23, 2002, assigned to Nokia Corporation and incorporated herein by reference, disclose a system in which multimedia messaging service (MMS) information, including video image data, can be transmitted to a call recipient at the same time that the call is being placed, simultaneously providing the recipient both with the phone call and video information. Similarly, a system can also send graphical information, such as group logos or an image of the sender, to a recipient device in conjunction with a phone call being placed by the sender.
Another feature that has become available on electronic devices in recent years includes the ability for a device to automatically create custom videos. One such application incorporating this feature is entitled the "Movie Director" and is included on mobile telephones sold by the Nokia Corporation. The Movie Director is capable of automatically generating music videos from a user's own video clips and music files. The Movie Director automatically cuts video clips in appropriate locations, adds effects to the audio being used, and adds graphics in order to enhance the visual appearance of the new "video." However, this product currently is "stand alone" in nature and is not related to the placing or receipt of telephone calls.

System and method for providing an automatic generation of user theme videos for ring tones and transmittal of context information


The present invention relates to a process for preparing polyarylate, and more specifically, to a process for preparing polyarylate by interfacial polymerization of a bivalent phenol compound and an aromatic dicarboxylic acid or a halide thereof, which comprises mixing a cationic catalyst for the phase transition and a nonionic surfactant in a predetermined ratio, to further increase the yield of polyarylate, as compared with the case of using each of the nonionic surfactant and the cationic catalyst for the phase transition alone.

Generally, polyarylate refers to a linear aromatic polyester resin prepared by poly-condensing an aromatic diol and an aromatic dicarboxylic acid. Such the polyarylate resin can have various molecular formulas depending upon its raw materials used. Among others, mention may be typically made of a polyarylate resin comprising the repeating units represented by the following formula 1, which is prepared by reacting bisphenol A as a bivalent phenol, and terephthalic acid or isophthalic acid as a di-carboxylic acid by polycondensation.

The polyarylate resin of the formula 1 is known in the art as an engineering plastic which is excellent in overall physical properties, and it can be widely used in the field of electric and electronic appliance part, for example, a switch, a socket, parts of a microwave, a relay case, and a plate since it has high heat resistance, excellent mechanical strength, and transparency. Further, in the mechanical field, it can be widely used as various raw materials or packaging materials to prepare various products, such as inner and/or outer parts of watches, parts of optical machines, parts of heating devices including a contact breaker of gas, lenses for a housing or an automobile, overall housing products, and instrument boards.
Examples of the process for preparing polyarylate include interfacial polymerization, solution polymerization and melting polymerization, and among these, the interfacial polymerization is widely used since it advantageously allows easy removal of the by-products and inhibition of an exothermic effect. In the interfacial polymerization for preparing polyarylate, a cationic catalyst for the phase transition can be added to increase a polymerization reaction rate.


A workpiece ejector and a method for ejecting workpieces from a turning machine such as a lathe. The turning machine has at least one spindle for receiving workpieces therethrough and at least one chuck associated with the spindle for holding a workpiece during machining operations. In one embodiment, the ejector includes a piston mounted at a location outside the spindle and proximate the chuck, the piston having a first end adapted to engage the workpiece and being movable between a first position where the first end is located outside the spindle and a second position where the first end and at least a portion of the piston are within the spindle. An actuator is operative to move the piston from the first position toward the second position. The actuator may include a mechanical spring.

Various types of feed mechanisms exist in the machine tool industry to automate the loading and/or unloading of workpieces into and out of a turning machine. Turning machines such as conventional hollow-spindle lathes may include a motor-driven rotating spindle which has a collet chuck mechanism connected to one end thereof for gripping material to be machined. In initial workpiece machining, which may be termed primary machining operations, workpieces may be machined from raw bar stock that extends from within the spindle and is gripped by the collet mechanism. After the primary machining is completed, the machined workpiece may be cut from the bar stock. Thereafter, the collet mechanism may be opened and additional bar stock may be fed through the spindle so that a new portion of the stock material may be received in the collet chuck mechanism for machining. This cycle is repeated to form several machined workpieces from the bar stock supplied through the spindle.
In many instances, secondary machining operations may be performed on workpieces that have previously been machined using the primary machining operation described above. These secondary operations are required, for example, when a different tool is needed to perform additional machining. In such cases, the previously-machined workpieces may be individually placed in the collet mechanism for further machining. In these secondary machining operations, the machined workpiece is held by the collet mechanism. Once the desired machining is completed on the workpiece, the machined workpiece must be ejected from the collet mechanism.
In other applications, multi-spindle lathes may be used to manufacture a machined part. Primary machining operations may be performed on bar stock material extending from a first spindle, whereafter the workpiece may be transferred to a second spindle for secondary machining operations. Generally, bar stock material will not be located in the second spindle, and finished workpieces may therefore be ejected through the second spindle.
Various workpiece ejectors have been proposed for use in turning machines, such as conventional lathes used in secondary operations. Conventional workpiece ejectors may generally include an elongated ejector push rod that extends through the spindle of an otherwise conventional lathe. The ejector push rod may be attached to an external plate that is driven by fixed, external air actuators to move the push rod into engagement with a workpiece and thereby eject the workpiece from the collet mechanism. As a result of the inclusion of external actuators, the space required for installation of a lathe including such an ejector may be substantially greater. In addition, conventional ejectors of this type may be costly and complex.
Other workpiece ejectors, such as the type disclosed in U.S. Pat. No. 5,715,735, are located inside the spindle, occupying some of the space which would otherwise be available for workpieces, and thereby limiting the size of the workpiece that can be machined. An additional drawback of this type of spindle-contained ejector is that it may deposit the finished workpiece in an area generally in front of the chuck, on one of the lathe surfaces, such as a chip pan or the lathe bed. Once this limited area fills up, manual intervention may be required in order for the accumulated finished workpieces to be removed.
Still other workpiece ejectors may be designed such that the ejecting mechanism, such as a spring or a pneumatically actuated piston or drive rod, will be restrained by the closed chuck holding the workpiece. When the chuck begins to open, and before if has fully released the workpiece, the spring or pneumatic device will begin the ejection, thereby potentially damaging the surfaces of the workpiece, due to contact with the chuck jaws during ejection. Such movement of the workpiece before the chuck has fully released the workpiece may not be suitable when a fine surface finish is desired.
Improvements to unloading devices for turning machines are therefore desirable.


A method of making a food serving tray assembly comprising the step of molding a hand portable container such that the container has a serving platter and a receptacle platter. The serving platter includes a disposal opening and serving wells for receiving food items. The receptacle platter and serving platter releasably couple to one another in a serving configuration and a transport configuration. The serving platter also has an outer peripheral wall and a plurality of dividing walls defining and separating adjacent serving wells; and the serving platter is generally received within the outer peripheral wall of the receptacle platter with the bottom of the receptacle platter and the dividing walls of the serving platter collectively isolating the wells from one another when the food serving tray assembly is in the transport configuration.

Trays for snacks and appetizer-type foods are generally known. Such trays provide a place to display these foods for presentation and for eating. They also generally make it easier to transport these foods. Unfortunately, many trays do not have seating lids that enable them to serve as food containers during transport from one location to another, e.g., from a restaurant to a home. Therefore, when foods that are traditionally presented on a tray are transported from one location to another, a container other than the tray is generally used during transport.
Another problem that exists, particularly for foods such as chicken wings that create their own waste, is finding a place to put the waste prior to its being thrown away. In most cases, a trash receptacle is not located within easy reach of a table or other dining area, typically because it is unsanitary or unsightly. As such, a diner is faced with the problem of having a place to put the waste while the food creating the waste is being eaten. Generally, such waste is unappetizing and an eater would prefer to have the waste out of sight while continuing to eat.
Anderson et al. U.S. patent application Ser. No. 11/870,538, which published as U.S. Patent Application Publication No. 2008/0029427, both of which patent references are incorporated herein by reference, address one or more of the foregoing problems. While the solutions presented therein may be suitable for their intended purposes, needs exists for alternative solutions to one or more of the foregoing problems. One or more preferred embodiments of the present invention provide such an alternative.

Making food serving tray assembly having disposal opening with deep serving wells


A coupling, which has a longitudinal bore for fluids to pass through, for connecting a tube to a pair of fittings that can be tightened and loosened with a wrenching tool, including a nipple positioned at one end of the coupling; a first threaded mating portion positioned at an opposite end of the coupling; a second threaded mating portion positioned adjacent the nipple; a wrenching portion disposed on the coupling having a front end and a rear end and extending above the first threaded mating portion with the wrenching portion rear end including a shoulder extending below the wrenching portion front end; and, whereby the first threaded mating portion engages one of a pair of fittings and the second mating portion engages the other of a pair of fittings.

In the past, there have been numerous attempts to make couplings that connect tubes to various fittings. For example, there are couplings that have an end press fitted into either the elbow or the diverter while the other end of the coupling, that connects to the tube, has a barbed nipple and a male threaded portion in conjunction with a nut N to secure the tube to the coupling.
Other couplings employ a threaded end, which screws into the diverter or the elbow, and a barbed nipple to secure the tube to the coupling.
The couplings used in the past that only employ a barbed nipple to connect to the tube have failed to provide the necessary securing of the tube. Namely, when the fluid pressure within the tube line increases, the tube will slip off the barbed nipple and cause system failure.
With regard to the couplings employing an end that is press fitted into other fittings, there have been numerous problems. For example, when a diverter malfunctions, or breaks, one cannot simply replace the diverter, but rather both the diverter and the coupling must be replaced. One must replace both because the coupling cannot be removed from the diverter, since they are press fitted together. An additional problem is that the "O" ring that seals the coupling to the diverter cannot be replaced, nor can the spring within the diverter be replaced or cleaned. Another problem that has developed with the press fit couplings is the flaking-off of any plating contained on the coupling. The flaking occurs because oil seeps out from the material of the coupling. When the coupling is being machined, oil is used to reduce the heat and to facilitate the machining. After machining, the coupling is cleaned off; however, minute amounts of oil remain in the material. Subsequent to machining, the coupling is plated with a anti-corrosion material. When the coupling is press fitted to the other fittings, such as the diverter or the elbow, the pressure exerted on the press fitted portion of the coupling causes the minute amounts of oil to seep from the coupling. This seepage forming under the plating causes the plating to flake off. The hazard is that the flakes can then pass into the fluid-line and anti-corrosion efforts are lost.
In and above these shortcomings, the previous couplings have also failed to provide an easy and efficient way to install, remove, tighten or loosen the coupling to and from other fittings. To tighten or loosen any of the previous couplings, it is likely that one would either damage necessary threads or damage or collapse the thin nipple by using some wrenching tool, like vice grips.
These attempts have not all succeeded in providing: the necessary securing of the tube to the coupling; the ability to be able to replace the diverter elbow or coupling; or, an easy and efficient way to install, remove, tighten or loosen the coupling.

Coupling assembly for a fluid purification system


Disclosed is a sensor for sensing the presence of an analyte component without relying on redox mediators. This sensor includes (a) a plurality of conductive polymer strands each having at least a first end and a second end and each aligned in a substantially common orientation; (b) a plurality of molecular recognition headgroups having an affinity for the analyte component and being attached to the first ends of the conductive polymer strands; and (c) an electrode substrate attached to the conductive polymer strands at the second ends. The electrode substrate is capable of reporting to an electronic circuit reception of mobile charge carriers (electrons or holes) from the conductive polymer strands. The electrode substrate may be a photovoltaic diode.

The present invention relates to biosensors and chemical sensors. More particularly, it relates to sensors having a chemical or biochemical species detection group connected to an electronic circuit by electrically conducting polymer strands.
Biosensors employing enzymes have been applied to the detection of numerous analyte species concentrations including glucose, cholesterol, or both glucose and cholesterol concentrations in whole blood samples. Such sensors and associated instruments employ an enzyme capable of catalyzing a reaction at a rate representative of the selected compound concentration in an assay mixture.
There are three general detection approaches employing a glucose enzyme electrode. The first and earliest measures oxygen consumption. The oxygen-sensing probe is an electrolytic cell with a gold (or platinum) cathode separated from a tubular silver anode by an epoxy casting. The anode is electrically connected to the cathode by electrolytic gel, and the entire chemical system is isolated from the environment by a thin gas-permeable membrane (often Teflon). A potential of approximately 0.8V (from solid-state power supply) is applied between the electrodes. The oxygen in the sample diffuses through the membrane and is reduced at the cathode with the formation of the oxidation product, silver oxide, at the silver anode. The resultant current is proportional to the amount of oxygen reduced. The analyzer unit operates over the range from 0.2 to 50 ppm of dissolved oxygen. Gases that reduce at 0.8V will interfere; these include the halogens and SO2. H2S contaminates the electrodes.
A second approach detects H2O2 production but requires an applied potential of approximately 0.65V (from solid-state power supply) applied between the electrodes, one of which is inside a permselective membrane. The H2O2 in the sample diffuses through the permselective membrane (if one is present) and is oxidized at the anode. Many metal, metal complexes, nonmetal, organic and biochemical species that oxidize at approximately 0.65V will interfere; such as ascorbic acid, amines, hydrazines, thiol compounds, catechols, hydroquinones, ferrocenes, and metalloporphyrins. The inside permselective membrane is not always capable of removing the complicated mix of possible interferences from the analyte matrix.
A third approach takes advantage of the fact that the enzymatic reaction requires two steps. First, the enzyme glucose oxidase (GOD) (EC 188.8.131.52) is reduced by glucose, then the reduced enzyme is oxidized to its initial form by an electron acceptor, i.e., a mediator. In natural systems, the mediator is oxygen. In biosensors, another mediator compound may be employed to transfer electrons between the enzyme and a conductive surface of an electrode at a rate representative of the enzyme catalyzed reaction rate when an appropriate potential is applied to the particular redox mediator in use. Such biosensors may employ amperometric measurements to determine glucose concentration in a whole blood sample. This involves an integrated sample measurement of the area under the ampere versus time curve, corresponding to the amount of glucose in the sample.
The mechanism by which a common amperometric sensor works is depicted in FIG. 1. A sensor 2 employs glucose oxidase (GOD), for example, as a molecular recognition group. Glucose oxidase catalyzes the oxidation of glucose to gluconolactone in analyte 4. This reaction involves the FAD/FADH2 redox center of the enzyme. Sensor 2 includes a molecular recognition group, region 6, attached to an electrode 8. When glucose in analyte 4 contacts GOD-FAD (glucose oxidase including the FAD redox center) in region 6, it is oxidized to gluconolactone. At the same time, the GOD-FAD is reduced to GOD-FADH2. This involves two electrons and two hydrogen ions being transferred to the FAD. Normally, in the absence of a sensor mediator, the GOD-FADH2 is reoxidized by atmospheric oxygen to GOD-FAD to complete the catalytic reaction. In the presence of a mediator, however, the GOD-FADH2 is sometimes reoxidized by a mediator (Mox). In this case, the GOD-FADH2 releases two hydrogen ions to analyte 4 and two electrons to the mediator. The resulting reduced mediator (Mred) may then be reoxidized by electrode 8 at an appropriate potential. The reoxidation of the mediator is accompanied by the transfer of an electron or electrons to electrode 8. This is the current that is monitored to provide a concentration of glucose.
In theory, a mediator may be any small molecule inorganic, organometallic or organic compounds, which are reduced by the enzyme, and oxidized by an appropriate applied potential at the electrode surface. The mediator should be designed to rapidly and efficiently transfer electrons between the enzyme and the electrode. Otherwise, ambient oxygen would oxidize nearly all of the reduced GOD and the desired signal would be very weak. The mediator should also transfer a total charge proportional to the glucose or cholesterol concentration in the sample. The current which results from the mediator oxidation is known as the Cottrell current which, when integrated with respect to time, gives the number of coulombs associated with the sensor reaction. The total coulombs passed is proportional to the amount of analyte.
Unfortunately, mediators are commonly provided as mobile "reagents" which diffuse to the enzyme where they are oxidized or reduced (depending upon the reaction catalyzed by the enzyme). The oxidized or reduced mediator then diffuses to the electrode surface where it gains or loses an electron. Unfortunately, such mechanism is dependent upon the continuing presence of recycled mobile mediators. As such compounds can leak from the electrode surfaces, there may be a gradual depletion in available mediator and a consequent reduction in sensor sensitivity. Examples of diffusing redox mediators include dyes (e.g., methylene blue), ferrocene derivatives (Cass, A E G; Davis, G; Francis, G D; Hill, H A O; Aston, W J; Higgins, I J; Plotkin, E V; Scott, L D L; Turner, A P F: Ferrocene-Mediated Enzyme Electrode for Amperometric Determination of Glucose. Anal. Chem. 56:667–671, 1984), components of conducting organic metals and quinones.
Also, available sensors applying the above amperometric approach to the detection of glucose, cholesterol, lactate, H2O2, NAD(P)H, alcohol, and a variety of other compounds in whole blood samples, can have other serious complicating problems. For example, the percentage of sensor surface area covered by blood can vary; sometimes the blood sample does not cover the entire electrode. This may be caused by a poorly adherent enzyme (often applied by spraying) thus allowing leakage of blood or other analytes along the edges of the electrode. A related problem results from hydration of the reaction area prior to test. This dilutes the ligand (e.g., glucose) concentration and therefore gives a lower reading than would be accurately given by an unhydrated surface.
Further, the partial pressure of molecular oxygen (O2) may complicate the interpretation of sensor data. Molecular oxygen is the natural electron acceptor mediator of the enzyme glucose oxidase (GOD). Following oxidation of D-(+)-glucose by GOD, reduced glucose oxidase (GODred) will transfer electrons to O2 forming H2O2 in the absence of other mediators. In amperometric glucose biosensors described above, the unwanted O2 side reaction competes with synthetic chemical mediators for electrons supplied by the GODred enzyme. Calibration of GOD-based biosensors at different altitudes (i.e., different partial pressures of O2) may be a problem if electron transfer rates of selected synthetic chemical mediators are not orders of magnitude faster than the O2 side reaction.
Humidity (i.e., H2O) may be another potential problem if mass action of H2O and O2 present drives the enzyme catalyzed oxidation product of D-gluconolactone in reverse back to the reduced starting material, D-(+)-glucose. Catalase, a common contaminant of glucose oxidase preparations, may be driven in reverse by mass action of excess H2O and O2 producing 2 moles of H2O2. H2O2 buildup combined with D-gluconolactone could drive the glucose oxidase reaction in reverse by mass action back to D-(+)-glucose.
Other problems associated with known amperometric sensors include, for example, (1) difficulty in fitting the Cottrell current curve (i.e., ampere-time graph), (2) sampling with enough frequency to accurately obtain the time integral of Cottrell current, (3) high applied potential at the electrode causing indiscriminate oxidation or reduction of interfering substances, and (4) complicated electronic circuits requiring potentiostat and galvinostat instrumentation.
Some of the above drawbacks of the current amperometric biosensors have been noted and analyzed (see, Schuhmann, W: Chap. 9. Conducting Polymers And Their Application In Amperometric Biosensors. In: Diagnostic Biosensor Polymers. ACS Symposium Series 556. Usmani, A M; Akmal, N; eds. American Chemical Society; Washington, D.C.; 1994; pp. 110–123). First, due to the fact that the active site of redox enzymes is in general deeply buried within the protein shell, direct electron transfer between enzymes and electrode surfaces is rarely encountered. This is especially true for enzymes which are integrated within non-conducting polymer membranes in front of the electrode surface. Hence, electron transfer is usually performed according to a 'shuttle' mechanism involving free-diffusing electron-transferring redox species for example the natural electron acceptor O2 or artificial redox mediators like ferrocene derivatives (Cass, A E G; Davis, G; Francis, G D; Hill, H A O; Aston, W J; Higgins, I J; Plotkin, E V; Scott, L D L; Turner, A P F: Ferrocene-Mediated Enzyme Electrode for Amperometric Determination of Glucose. Anal. Chem. 56:667–671, 1984), osmium complexes (Heller, A: Electrical Wiring of Redox Enzymes. Acc. Chem. Res. 23(5):128–134, 1990), or quinones. Due to the necessity for the redox mediators to diffuse freely between the active sites of the enzymes and the electrode surface, these electrodes show a limited long-term stability as a consequence of the unavoidable leaking of the mediator from the sensor surface. Additionally in the case of the natural redox couple O2/H2O2, the sensor signal is dependent on the O2 partial pressure, and a high operation potential has to be applied to the working electrode giving rise to possible interferences from cooxidizable compounds. The second drawback is related to the fabrication of these sensors. The physical assembling of an enzyme membrane and an electrode is extremely difficult to automate and thus in principal incompatible with microelectronic fabrication techniques. Additionally, the miniaturization as well as the integration of individual biosensors into a miniaturized sensor array is impossible with techniques which are mainly based on the manual deposition of a droplet of the membrane-forming mixture onto the electrode surface.
Consequently, the next generation of amperometric enzyme electrodes has to be based on immobilization techniques which are compatible with microelectronic mass-production processes and easy to miniaturize. Additionally, the integration of all necessary sensor components on the surface of the electrode has to prevent the leaking of enzymes and mediators simultaneously improving the electron-transfer pathway from the active site of the enzyme to the electrode surface.
In addition to amperometric mechanisms, which rely on detecting current generated from faradaic reactions, a potentiometric mechanism may be employed to sense analyte concentration. Potentiometric techniques monitor potential changes between a working electrode and a reference electrode in response to charged ion species generated from enzyme reactions on the working electrode. A very common potentiometric sensor is the pH sensor which registers changes in hydrogen ion concentration in an analyte. A microelectronic potentiometric biosensor, the Field Effect Transistor (FET) biosensor, has generated some interest. In this design, a receptor or molecular recognition species is coated on a transistor gate. When a ligand binds with the receptor, the gate electrode potential shifts, thereby controlling the current flowing through the FET. This current is detected by a circuit which converts it to an observed ligand concentration. Observed problems with potentiometric systems include, for example, (1) slow response of the electrode (i.e., seconds), (2) complicated electronic circuits for three electrode (i.e., working, counter, and reference electrode) electrochemical systems requiring potentiostat instrumentation, (3) low sensitivity, and (4) limited dynamic range.
Recently, two groups (Heller et al. and Skotheim et al.) have explored and developed redox polymers that can shuttle electrons from the enzyme to the electrode. The groups have "wired" the enzyme to the electrode with a long redox polymer having a dense array of electron relays. Each relay is a redox site bound to the polymer backbone. Electrons move along the polymer by hopping from one redox appendage to the next. The polymer penetrates and binds the enzymes, and is also bound to the electrode.
Heller et al. have conducted work on Os-containing redox polymers. They have synthesized a large number of such Os-containing polymers and evaluated their electrochemical characteristics (Gregg, B A; Heller, A: Redox Polymer Films Containing Enzymes. 1. A Redox-Conducting Epoxy Cement: Synthesis, Characterization, and Electrocatalytic Oxidation of Hydroquinone. J. Phys. Chem. 95:5970–5975, 1991). Their most stable and reproducible redox polymer is a poly(4-vinyl pyridine) to which Os(bpy)2Cl2 has been attached to ⅙th of the pendant pyridine groups. The resultant redox polymer is water insoluble. To make it water soluble and biologically compatible, Heller et al. have partially quaternized the remaining pyridine pendants with 2-bromoethyl amine. The redox polymer is water soluble and the newly introduced amine groups can react with a water soluble epoxy e.g., polyethylene glycol diglycidyl ether and GOD to produce a cross-linked biosensor coating-film. Such coating-films produced high current densities and a linear response to glucose up to 600 mg/dL (U.S. Pat. No. 5,262,035 to Gregg et al.).
Heller describes the electrical wiring of redox enzymes for use as amperometric biosensors (Heller, A: Electrical Wiring of Redox Enzymes. Acc. Chem. Res. 23(5):128–134, 1990). The Heller approach is an improvement over amperometric enzyme electrodes based on diffusing redox mediators, including dyes, ferrocene derivatives, components of conducting organic metals, and quinones, all described above. In the Heller approach, redox centers of a redox polymer polycation (e.g., 2[Os-(2,2′-bipyridine)2(poly(vinylpyridine))Cl]1+/2+) are electrostatically and covalently bound to the enzyme and relays electrons to the electrode, on which a segment of the polycation is adsorbed. Binding of the redox polymer polycation to the electrode can be electrostatic when the electrode has a negative surface charge.
Fluctuations in current with partial pressure of oxygen (e.g., oxygen concentration in blood), depend on the ratio of the rate of direct electroxidation of the FADH2 centers to their rate of oxidation by molecular oxygen, and therefore on the rate of electron transfer to, and the electrical resistance of, the three-dimensional wired-enzyme structure. At high osmium-complex concentrations, and in sufficiently thin layers, the competition is won by electron transfer to the electrode via the osmium centers, and the electrodes are relatively insensitive to oxygen (Heller, A: Electrical Wiring of Redox Enzymes. Acc. Chem. Res. 23(5):128–134, 1990. Gregg, B A; Heller, A: Cross-Linked Redox Gels Containing Glucose Oxidase for Amperometric Biosensor Applications. Anal. Chem. 62:258–263, 1990. Surridge, N A; Diebold, E R; Chang, J; Neudeck, G W: Chap 5. Electron-Transport Rates In An Enzyme Electrode For Glucose. In: Diagnostic Biosensor Polymers. ACS Symposium Series 556. Usmani, A M; Akmal, N; eds. American Chemical Society; Washington, D.C.; 1994; pp. 47–70).
Electrodes based on conducting polypyrroles with ferrocenes also have been reported (Hale, P D; Inagaki, T; Karan, H I; Okamoto, Y; Skotheim, T A: A New Class of Amperometric Biosensor Incorporating a Polymeric Electron-Transfer Mediator. J. Am. Chem. Soc. 111(9):3482–3484, 1989).
Skotheim et al. have used flexible polymer chains to act as relays. Their polymers provide communication between GOD's redox centers and electrode. No mediation was found when ferrocene was attached to a non-silicone backbone. Their ferrocene-modified siloxane polymers were said to be stable and non-diffusing (Boguslavsky, L I; Hale, P D; Skotheim, T A; Karan, H I; Lee, H S; Okamoto, Y: Novel Biosensors For Specific Neurotransmitters Based On Flavoenzymes And Flexible Redox Polymers. Polym. Mater. Sci. Eng. 64:322–323, 1991).
Unfortunately, the redox polymer systems of Heller et al. and Skotheim et al. have a limited electron transfer rate based on electron hopping between dense electron relay pendant groups. Further, their "wire" redox centers must be designed to undergo reaction at a potential close to that of the enzyme catalyzed reaction. The closer the potential is to the redox potential of the enzyme itself, the lesser the likelihood that a potentially interfering substrate will be spuriously oxidized. Unfortunately, to address this issue limits the range of polymer redox couple and molecular headgroup combinations.
A fundamental presupposition for the construction of reagentless amperometric enzyme electrodes is the design of a suitable electron-transfer pathway from the active site of the enzyme to the electrode surface. According to Marcus theory (Marcus, R A; Sutin, N: Electron Transfers In Chemistry And Biology. Biochim. Biophys. Acta 811:265–322, 1985) a redox mediator with a low reorganization energy after the electron transfer has to be able to penetrate into the active site of the enzyme to shorten the distance between the prosthetic group (e.g., FAD/FADH2) and the mediator. Hence, the rate constant of the electron-transfer reaction can be increased. After this 'first' electron transfer the redox equivalents have to be transported to the electrode surface via mechanism having a rate constant which is in the range of the turnover rate of the enzyme. In the shuttle mechanism mentioned above (having mobile mediators), the electron transport involves diffusion of redox mediators. In the "wired" redox polymer sensors described above, electron transport involves hopping from one redox center to the next on the polymer backbone.
In a recent study, Aizawa et al. discuss a reversible electron transfer between the prosthetic group of pyrrolo quinoline quinone (PQQ) enzyme (fructose dehydrogenase) and an electrode through a molecular interface (Aizawa, M; Khan, G F; Kobatake, E; Haruyama, T; Ikariyama, Y: Chap. 26. Molecular Interfacing of Enzymes on the Electrode Surface. In: Interfacial Design and Chemical Sensing. ACS Symposium Series 561. Mallouk, T E; Harrison, D J; eds. American Chemical Society, Washington, D.C., 1994, pp. 305–313). The PQQ moieties of randomly oriented fructose dehydrogenase (FDH) which are very close to the transducer electrode can easily transfer their electrons to the electrode (Shinohara, H; Khan, G F; Ikariyama, Y; Aizawa, M: Electrochemical Oxidation and Reduction of PQQ Using a Conducting Polypyrrole-Coated Electrode. J. Electroanal. Chem. 304:75–84, 1991. Khan, G F; Shinohara, H; Ikariyama, y; Aizawa, M: Electrochemical Behaviour of Monolayer Quinoprotein Adsorbed on the Electrode Surface. J. Electroanal Chem. 315:263–273, 1991). However, the prosthetic groups of FDH located far from the electrode can not provide their electrons, as the distance from the electrode exceeds the maximum electron transfer distance (˜25 Å). Therefore, to make the FDH (EC 22.214.171.124, MW: 141,000) on the electrode surface electrochemically active, Aizawa et al. introduced an ultrathin conductive polypyrrole (PP) membrane as a molecular interface as "wiring" to assist the electron transfer from PQQ to the electrode. Unfortunately, the wiring used by Aizawa is randomly oriented and does not necessarily present enzyme at optimal position with respect to the analyte.
What is needed is an improved sensor design that rapidly transfers electrons from headgroup redox reactions to an electrode, does not rely on a redox relay such as freely diffusing mediators, and optimally orients the headgroup with respect to the analyte.
A great number of approaches for microfabrication of chemical sensors are currently under way, particularly in the areas of field effect transistor (FET)-based chemical sensors, metal oxide gas sensors, and biosensors. Since Janata et al. first reported micro-enzyme electrodes based on FET (Caras, S; Janata, J: Field Effect Transistor Sensitive to Penicillin. Anal. Chem. 52:1935–1937, 1980), a number of groups have been employing microfabrication techniques (e.g., photolithography) such as those employed in semiconductor device technology to fabricate micro-enzyme electrodes. Despite enormous efforts of many groups, the FET-based micro-enzyme electrodes of practical use have not been realized yet, largely because of the problems associated with potentiometric methods general lack of a fast response, high sensitivity, and wide dynamic range.
For the construction of reagentless enzyme electrodes (e.g., electrodes analogous to those of Heller et al. and Aizawa et al.) one has to focus on a technique for the modification and functionalization of electrode and even micro-electrode surfaces to allow the strong binding of the enzyme and the redox mediator taking into account the presuppositions for an effective and fast electron transfer between the enzyme and the electrode. These features requirements are in principle met with enzyme electrodes based on redox-sensitive hydrogels, however, the manual deposition of these hydrogels is not compatible with mass-production techniques.
The electrochemical deposition of conducting-polymer layers occurs exclusively on the electrode surface and can hence be used for the immobilization of enzymes either covalently using functionalities on the polymer film or physically entrapped within the growing polymer film. As the conducting-polymer film itself does not participate in the electron transfer, mediator-modified enzymes entrapped within a polypyrrole layer have been used for the construction of a reagentless oxidase electrode.
Electrochemical deposition methods of the prior art typically use high current density and voltage potential conditions which destroy the orderly Helmholtz double-layer at the electrode surface (U.S. Pat. No. 5,215,631 to Westfall). Resulting disorderly depositions at electrode surfaces produce random polymer structures which lack orientational and positional order. Aizawa et al. "wired" PQQ-FDH in their sensors with ultrathin conductive polypyrrole (PP) membrane as a molecular interface. Electrochemical synthesis of molecular-interfaced FDH on Pt electrode was prepared by the following two steps: (1) potential-controlled adsorption of FDH, and (2) electrochemical polymerization of polypyrrole. These steps employ high voltage and current density electrochemical deposition conditions to produce polymer (FDH and polypyrrole) depositions on the Pt electrode that are randomly oriented. Therefore, this device must operate at high (˜400 mV) operating potential resulting in possible interfering cooxidizable species.
What is needed is an improved technique for depositing molecular recognition groups and associated wiring, if necessary, that provides a strong direct connection between an electrode and the molecular recognition groups, and allows the molecular recognition groups to be aligned in a common orientation.