Provided are novel peptidomimetic isoprenyl transferase inhibitors, methods for synthesizing such inhibitors, and methods for the use of such inhibitors for the treatment of tumors.

This invention concerns peptidomimetic isoprenyl transferase inhibitor compounds useful in the treatment of human cancers.
Ras oncogenes are prevalent in over 20% of all human cancers. The compounds of the invention inhibit the posttranslational processing of ras proteins, thereby inhibiting ras protein function.
Ras proteins are present in all cell types, and are thought to take part in normal cellular signal transduction mechanisms. Ras mutations are thought to cause hyperproliferation of cells; mutated ras genes are known as oncogenes. In particular, ras oncogenes are found in approximately 30% of all lung cancer, 30% of all myeloid leukemia, 50% of all colorectal carcinoma, and 90% of all pancreatic carcinoma. Barbacid, M., Ann. Rev. Biochem., 56:779 (1987), Bos, J. L., Cancer Res. 49:4682 (1989). Examples of ras mutations are found in H-ras, K-ras, and N-ras.
Like other members of the superfamily of small GTP-hydrolyzing proteins, ras-encoded proteins, both normal and mutated, require post-translational processing for cell membrane association and biological activity. Maltese, W. A., FASEB Journal, 4:3319 (1990), Hancock, J. F. et aL, Cell, 57:1167 (1989).
The post-translational processing of ras proteins is signaled by a short carboxyl-terminus consensus sequence, known as the CAAX box. This sequence signals which of two isoprenyl groups, farnesyl or geranylgeranyl, is to be attached to ras proteins by cellular enzymes. A farnesyl group is a 15 carbon isoprenyl group, while a geranylgeranyl group is a 20 carbon isoprenyl group. Isoprenyl groups are multimers of isoprene, a 5 carbon compound. For farnesylated proteins, such as ras, lamin B, and xcex3-transducin, C is cysteine, A is an aliphatic amino acid, and X (the carboxyl-terminal amino acid) is methionine, serine, or glutamine. Geranylgeranylated proteins such as Rap, Rho and other small GTP-binding proteins, have similar CAAX sequences in which X is usually leucine, or occasionally is phenylalanine. In vivo, ras proteins are preferentially farnesylated.
Post-translational processing of the ras-encoded protein includes at least three steps. First, reaction with farnesyl pyrophosphate attaches a farnesyl group to the Cys residue on the sulfhydryl side chain. Second, a specific protease cleaves the three carboxy-terminal amino acids. Third, the carboxylic acid moiety of the now-terminal cysteine is methylated to a methyl ester. The farnesyl transferase enzyme (FTase) mediates the attachment of the farnesyl group to a protein. The geranylgeranyl transferase I enzyme (GGTase I) mediates the attachment of the geranylgeranyl group to a protein.
Post-translational processing, particularly farnesylation, of ras proteins is critical for in vivo ras protein function. Among other things, farnesylation of ras oncogene products is known to be essential for ras-induced cellular transformation. Cox, A. D. and Der, C. A. Critical Rev. in Oncogenesis, 3 (4) 365-400 (1992). Upstream of FTase, farnesylation of a ras protein can be inhibited by mevalonate synthesis inhibitors such as lovastatin or compactin, which are HMG-CoA reductase inhibitors. Direct inhibition of FTase by short peptides or peptide-like substrates has also been demonstrated. Since ras proteins mediate the transformation of normal cells to cancer cells in many human cancers, compounds which inhibit prenylation will, therefore, inhibit the growth of ras-related cancers. A group of such compounds and methods for their synthesis are described in U.S. Pat. No. 5,840,918, the disclosure of which is incorporated by reference herein in its entirety, particularly the disclosure from column 17 to column 30, and Examples 1 to 175. Other compounds are disclosed in international patent publication WO 98/38162A1, which is also incorporated by reference herein in its entirety.
This invention is directed to novel peptidomimetic isoprenyl transferase inhibitor compounds useful in the treatment of ras-associated human cancers. Ras-associated human cancers are those in which a mutated form of the ras gene product are commonly found, e.g., lung cancers, myeloid leukemia, colorectal carcinoma, pancreatic carcinoma, and the like. In particular, the invention is directed to compounds with the following formulas:
The invention concerns the compounds themselves, the preparation of these compounds, and the in vitro and in vivo isoprenyl transferase activity of these compounds. Another aspect of the invention is directed to the clinical use of the compounds to decrease isoprenyl transferase activity in biological systems, and to the physiological consequences of inhibition of isoprenyl transferase. In particular, the invention is directed to methods of using the compounds to treat ras-associated human cancers.
The compounds of the invention may be used clinically to treat medical conditions where a decrease in isoprenyl transferase activity is beneficial. The compounds of the invention can be used to inhibit post-translational modification of oncogenic ras proteins by FTase, thereby down-regulating ras protein-stimulated cell proliferation. Accordingly, the invention is directed to the treatment of various forms of ras-associated cancer. Some compounds of the invention inhibit post-translational modification of ras proteins by the related GGTase I, which also results in down-regulation of ras protein function. Certain compounds of the invention are selective or specific for FTase and are preferred over compounds which are selective for GGTase I.
Further, compounds of the present invention may contain asymmetric carbon atoms and hence can exist as stereoisomers, both enantiomers and diastereomers. All stereoisomers and mixtures thereof are considered to fall within the scope of the present invention. The synthetic examples cited herein provide the most preferred isomer.
The invention is also directed to prodrugs and pharmaceutically acceptable salts of the compounds described, and to pharmaceutical compositions suitable for different routes of drug administration and which comprise a therapeutically effective amount of a described compound admixed with a pharmacologically acceptable carrier.
The compounds of the invention have been found to be surprisingly and unexpectedly superior inhibitors of in vivo isoprenylation, i.e., isoprenylation of proteins, particularly ras proteins, when contacted with intact cells, compared with other known isoprenyltransferase inhibitor compounds. Without being bound by theory, it is believed that the increased lipophilicity of the compounds of the invention relative to other similar compounds provides for greater in vivo activity due to greater cell permeation.
Definitions
The term xe2x80x9cprodrugxe2x80x9d as used herein refers to any compound that may have less intrinsic activity than the xe2x80x9cdrugxe2x80x9d but when administered to a biological system generates the xe2x80x9cdrugxe2x80x9d substance either as a result of spontaneous chemical reaction or by enzyme catalyzed or metabolic reaction. Reference is made to various prodrugs such as acyl esters, carbonates, and urethanes, included herein. The groups illustrated are exemplary, not exhaustive and one skilled in the art could prepare other known varieties of prodrugs. Such prodrugs of the compounds of the invention fall within the scope of the present invention.
The term xe2x80x9cpharmaceutically acceptable saltxe2x80x9d includes salts of the compounds of the invention derived from the combination of a compound of this invention and an organic or inorganic acid. The compounds of the invention are useful in both free base and salt form. In practice the use of salt form amounts to use of base form; both forms are within the scope of the present invention.
The terms xe2x80x9ctreatmentxe2x80x9d or xe2x80x9ctreatingxe2x80x9d include prophylactic or therapeutic administration of compounds of the invention, for the cure or amelioration of disease or symptoms associated with disease, and includes any benefits obtained or derived from the administration of the described compounds.
Further, compounds of the present invention may contain asymmetric carbon atoms and hence can exist as stereoisomers, both enantiomers and diastereomers. All stereoisomers and mixtures thereof are considered to fall within the scope of the present invention. The synthetic examples cited herein provide the most preferred isomer.


A pedal assembly has a base and a pedal. The pedal is pivotally mounted on the base and has two mounting sleeve mounted between the base and the pedal. A resilient element is mounted between the mounting sleeves. A retaining element is secured to the base. Each mounting sleeve has a rubbing surface abutting against the pedal. Accordingly, gaps between the mounting sleeves and the pedal due to attrition will be automatically eliminated.

1. Field of the Invention
The present invention relates to a pedal, and more particularly to a pedal assembly that can eliminate gaps caused by attrition.
2. Description of Related Art
Drums play a very important role in a music performance. Basically, a drum has a head and can be hit by drumsticks, mallet or brush to generate sound. As for a bass drum, when a user steps a pedal assembly, a beater connected to the pedal is driven to hit the bass drum for generating sound.
With reference to FIG. 5, a conventional pedal assembly comprises a base (42), an operational beater (43) and a pedal (41). The base (42) is normally mounted on the ground and has two ears (420). The pedal (41) is provided inclinedly on the base (42) and has an actuating end and a pivotal end. The pivotal end is pivotally mounted between the ears (420) of the base (42) and has two side surfaces being required to abut closely against the ears (420) to make the pedal (41) stable relative to the base (42). The operational beater (43) is mounted pivotally on the base (42), connects to the actuating end of the pedal (41) and is driven by the pedal (41). At least one resilient element (430) is connected to the beater (43) to make the beater (43) and the pedal (41) to return to an original position automatically, such that users can step the pedal (41) repeatedly.
When users step on the pedal (41), the pedal (41) will pivotally rotate relative to the ears (420) of the base (42) and drive the beater (43) to hit the head of the bass drum. Since the pedal (41) rotate relative to the ears (420), attrition between the ears (420) and the side surfaces of the pedal (41) abutting against the ears (420) are unavoidable and gaps are easily generated. The gaps will make the pedal (41) unstable relative to the base (42).
To solve said problems of the conventional pedal assembly, a worn pedal (41) is detached from the base (42) and is replaced with a new pedal. However, this is not only inconvenient, but also uneconomical.
To overcome the shortcomings, the present invention provides a pedal assembly to obviate or mitigate the aforementioned problems.


A microelectronics substrate assembly comprising: an advanced ceramics substrate having a top surface and a bottom surface; a first metallized distribution plane on said top surface and a second metallized distribution plane on said bottom surface; an electrical connection between said first and second distribution planes; at least one first metallized pad on said top surface electrically isolated from said first distribution plane and at least one metallized pad on said bottom surface, electrically isolated from said second distribution plane, wherein said distribution planes and said metallized pads are arranged substantially symmetrically with respect to a plane between and parallel to said top and said bottom surfaces.

Microelectronic packages for power transistors have included an alumina ceramic substrate on whose top surface is disposed a metal heat sink such as copper onto which the die is attached, and two metallized pads to which leads are attached and the die is wire bonded. A metal heat sink, again such as copper, is disposed on the bottom surface of the ceramic substrate. The finished assembly is utilized in electronic apparatus containing circuit boards. The circuit board generally has cavities for accepting the power transistor package, and the bottom heat sink is placed in thermal contact with a heat sink located at the bottom of the cavity of the circuit board.
Although the metal heat sinks are useful in conducting heat away from the power transistor device while in operation, the mismatch between the thermal expansion coefficient of the material of the power device and the top metal heat sink, and between the ceramic and both metal heat sinks can cause failure of the bonds between these elements during thermal cycling experienced in operation. The same problems encountered with metal heat sinks are experienced in the prior art where beryllia is utilized as a substrate material.
Further, the packages of the prior art must be oriented in a particular position for assembly, due to the asymmetric distribution of package elements. This lessens the capability of the package to be easily assembled by automated equipment, and requires complex apparatus for positioning the substrate for processing.
It is therefore an object of the present invention to provide a microelectronics package without a significant thermal expansion coefficient mismatch between the package elements.
It is a further object of the present invention to provide a microelectronics package which is easily assembled by automated processing.
These and other objects and advantages of the invention set forth herein are accomplished by the present invention as described in the Specification and Claims which follow.


A device, in particular, a multi-channel oscilloscope, for the analysis of at least one measured signal transmitted via a multi-channel system, with several measurement channels. The device includes in each case a sampling device, a baseband mixing device, and a filter device, and an analysis device. The measured signal is supplied to the measurement channels and to the respective sampling devices for simultaneous sampling. The sampled measured signal is supplied to the baseband mixing devices connected downstream of the sampling devices for the mixing of the measured signal down into the baseband, to the filter devices connected downstream of the baseband mixing devices for the decimation of the sampled values of the measured signal in the baseband and to the analysis device connected to the filter devices for the analysis of the measured signal.

1. Field of the Invention
The invention relates to a device, in particular, a multi-channel oscilloscope, and to a method for the analysis of a measured signal transmitted via a multi-channel system.
2. Discussion of the Background
In communications technology, a multi-channel system is used for the transmission of signals, in order to increase the data rate per bandwidth used and to reduce the bit-error rate. A multi-channel system can be used, for example, in a wireless communications system, which provides a so-called single-input multiple-output (SIMO) system via one transmission antenna and several reception antennas, or a so-called multiple-input multiple-output (MIMO) system via several transmission antennas and several reception antennas. DE 101 14 052 C1 describes a radio transmission method with multiple transmission and reception antennas operating simultaneously within the same frequency band.
As a prerequisite for a particularly high-quality and accurate analysis and/or recording of the measured signal transmitted via the multi-channel system, the measured signal must be simultaneously de-coupled at outputs of the multi-channel system and simultaneously processed. In this context, with a multi-channel system comprising transmission antennas and reception antennas, it has hitherto generally been the case that a measured signal de-coupled at the one reception antenna is processed with a time offset relative to the measured signal de-coupled at the other reception antenna, that is to say, for example, supplied in a time succession to a sampling device and sampled with a time offset relative to one another. A time-offset processing of the measured signal de-coupled at several reception antennas restricts the measurement rate and leads to an impairment of the analysis results.

Device and method for the analysis of a measured signal transmitted via a multi-channel system


A cavern pressure control method includes storing compressible and possibly incompressible fluids in an underground storage volume, removing a portion or introducing additional incompressible fluid into the underground storage volume, possibly removing a portion or introducing additional compressible fluid into the underground storage volume, thereby producing a net pressure increase rate (Pinc) within the underground storage volume, wherein Pinc is maintained at less than a predetermined maximum increase value (PImax).

Hydrogen is commonly supplied to customers that are connected to a supplier's hydrogen pipeline system. Typically, the hydrogen is manufactured by steam methane reforming in which a hydrocarbon such as methane and steam are reacted at high temperature in order to produce a synthesis gas containing hydrogen and carbon monoxide. Hydrogen may then be separated from the synthesis gas to produce a hydrogen product stream that is introduced into the pipeline system for distribution to customers that are connected to the pipeline system. Alternatively, hydrogen produced from the partial oxidation of a hydrocarbon can be recovered from a hydrogen rich stream.
Typically, hydrogen is supplied to customers under agreements that require availability and reliability for the steam methane reformer or hydrogen recovery plant. When a steam methane reformer is taken off-line for unplanned or extended maintenance, the result could be a violation of such agreements. Additionally, there are instances in which customer demand can exceed hydrogen production capacity of existing plants in the short term. Having a storage facility to supply back-up hydrogen to the pipeline supply is therefore desirable in connection with hydrogen pipeline operations.
Considering that hydrogen production plants on average have production capacities that are roughly 50 million standard cubic feet per day, a storage facility for hydrogen that would allow a plant to be taken off-line, to be effective, would need to have storage capacity in the order of 1 billion standard cubic feet or greater.
In order to provide this large storage capacity, high pressure gases, such as but not limited to nitrogen, air, carbon dioxide, hydrogen, helium, and argon, are stored in caverns, whether leached in salt formations or created by hard rock mining. A minimum volume of gas is stored in the cavern to provide adequate pressure to maintain the integrity of the cavern and prevent the cavern roof from collapsing and to keep the cavern walls from moving inward. This minimum volume of gas is called the pad gas or base gas. The amount of gas stored in addition to the pad gas or base gas volume is called the working gas or working inventory. Business opportunities can require removing more gas volume from the cavern than the working gas volume. To meet this business need, the volume of pad gas or base gas can be reduced to provide additional volume. For the purpose of this invention, the definition of high pressure is defined as a pressure at or above 10 atm. For the purpose of this invention, the definition of cavern integrity is defined as the ability of the cavern to hold static pressure when blocked in for 48 hours such that the cavern gas pressure does not decrease for 48 hours when all flows in and out of the cavern are stopped.


There are provided (I) a process for producing a copolymer of ethylene, an α-olefin having from 3 to 20 carbon atoms and optionally a polyene, which comprises the step of copolymerizing those monomers in a polymerization reactor by feeding the following components (A), (B), (C1) and (D) to the polymerization reactor:                (A) a transition metal complex,        (B) an organic aluminum compound,        (C1) a halogen-containing compound, and        (D) a Lewis base,wherein those components are fed to the polymerization reactor without a preliminary contact of (1) the component (A) with the component (B), (2) the component (A) with the component (C1), (3) the component (B) with the component (C1), and (4) the component (B) with the component (D); and (II) a process for producing said copolymer, which comprises the step of copolymerizing those monomers in a polymerization reactor (i) by feeding to the polymerization reactor the components (A), (B), (D), (C2) a halogen-containing compound, which is a derivative of an aryl group-containing carboxylic acid, and (C3) a halogen-containing compound, which is not a derivative of a carboxylic acid, or (ii) by feeding thereto the components (A), (B), (D), (C3), and (C4) a halogen-containing compound, which is a derivative of a carboxylic acid containing an unsaturated bond-carrying linear organic group.

An ethylene-α-olefin-non-conjugated diene copolymer has hitherto been produced with a homogeneous vanadium catalyst (for example, JP 46-21212B).
There is also known a process for producing a branched chain-containing ethylene-α-olefin copolymer using a combination of the above-mentioned vanadium catalyst with a component functioning as a Lewis base (for example, JP47-23413B).
There is further known a polymerization process, wherein an organic aluminum compound, a vanadium compound, a halogenated hydrocarbon and a component functioning as a Lewis base are supplied to a polymerization reactor without preliminary contact of (1) the organic aluminum compound and the vanadium compound, (2) the organic aluminum compound and the halogenated hydrocarbon, or (3) the organic aluminum compound, the vanadium compound and the halogenated hydrocarbon (for example, JP 07-048412A).


In a heating cooker, an object to be heated is placed on a top plate and is heated by a heating unit located below the top plate. The top plate is translucent and a fluorescent display tube is located below the top plate. The top plate is configured to have spectral transmission characteristics in a visible light range such that the spectral transmission at a wavelength of approximately 500 nm corresponding to blue or green is substantially one third of a spectral transmission at a wavelength of approximately 700 nm corresponding to red such that the spectral transmission is gradually rendered larger as the wavelength is increased from approximately 500 nm to approximately 700 nm.

As this type of heating cooker, for example, an induction heating cooker is known in which a liquid crystal display is provided below the top plate and a backlight is provided in the rear of the liquid crystal display so that on-off state of a heating coil serving as a heating unit, an input power level and the like are displayed by the liquid crystal display (see patent documents 1 and 2, for example). In this construction, a portion of the top plate corresponding to the liquid crystal display is transparent so that displayed contents are visible therethrough from above.    Patent document 1: Gazette of JP-A-H07-94267    Patent document 2: Gazette of JP-A-2003-31347


The present invention uses the capacitive impedance component to constituted the first impedance and the inductive impedance component to constituted the second impedance, which is characterized as that the first and second impedances in series connection is configured to appear series resonance with the inputting bi-directional power to form a bi-directional divided power, thereby using the bi-directional divided power to drive the bi-directional conducting light emitting diode in parallel connection with the first impedance and second impedance.

(a) Field of the Present Invention
The bi-directional light emitting diode drive circuit in bi-directional power series resonance is disclosed by that a first impedance is constituted by a capacitive component, and a second impedance is constituted by an inductive component, whereof they are in mutual series connection, and their inherent series resonance frequency is the same as the frequency or period of the bi-directional power source to generate a series resonance status. Thereof it is characterized in that when in series resonance, a bi-directional divided power is formed across the two ends of the capacitive impedance component and the inductive impedance component in mutual series connection, whereby the divided power is used to drive a bi-directional conducting light emitting diode which is either parallel connected with the first impedance or the second impedance, or at least two bi-directional light emitting diodes which are respectively parallel connected across the two ends of the first impedance and the second impedance are driven by the divided power across the two ends of the first impedance and the two ends of the second impedance.
(b) Description of the Prior Art
The conventional light emitting diode drive circuit using AC or DC power source is usually series connected with current limit resistors as the impedance to limit the current to the light emitting diode, whereof the voltage drop of the series connected resistive impedance always result in waste of power and accumulation of heat which are the imperfections.

This patent is subject to a terminal disclaimer.

Bi-directional light emitting diode drive circuit in bi-directional power series resonance


The present invention relates to methods and devices that support mobility of a client across a campus, particularly mobility across VLANs and subnets, while preserving the client's assigned IP address. Both layer 2 and layer 3 packets are supported. Mobility support most clearly applies to wireless clients, but could apply to other kinds of mobile connections, even to wired connections. A smart server is adapted to support multiple VLANs and to modify and redirect packets in sessions with a client that moves from one VLAN to another, preserving the client's assigned IP address. Two or more smart servers, in cooperation with a smart manger, modify packets and tunnel them between smart servers when a client that moves from one VLAN to another and from one smart server to another, again preserving the client's assigned IP address. A similar approach applies to support mobility of a client that moves between subnets that are supervised by two smart servers, with the second smart server acting on behalf of the first smart server and tunneling packets back and forth to the first smart server. Particular aspects of the present invention are described in the claims, specification and drawings.

The present invention relates to methods and devices that support mobility of a client across a campus, particularly mobility across VLANs and subnets, while preserving the client's assigned IP address. Both layer 2 and layer 3 packets are supported. Layer 2 and 3 refer to the OSI seven-layer model. Mobility support most clearly applies to wireless clients, but could apply to other kinds of mobile connections, even to wired connections.
As computers become more ubiquitous and all of us spend more time using our computers, we personalize or customize them and come to depend on the particular environment that we create. Improvements in portable devices encourage us to carry along our custom environments, moving from place to place with a laptop under our arm.
Concurrently, the extended reach of networks across campuses, into meeting places, coffee houses, hotels, airports and elsewhere has encouraged development of IP-based devices, such as voice over IP (VOIP) telephones and, particularly, wireless IP devices, such as IEEE 802.11 conforming and Bluetooth VOW telephones and PDAs. The new devices tend to move with us.
The Mobile IP Working Group of the Internet Engineering Task Force has made extensive efforts to standardize protocols for device mobility. RFC 3344 sets forth an elaborate standard that may some day be widely implemented, but it is not presently. Implementation will require support from operating system vendors and others. It may prove impractical for some mobile devices that have modest processing capabilities, such as WLAN VoIP telephones and PDAs, ever to implement the standards. Widespread implementation seems to be years away.
At least two special cases of mobility exist, based on current infrastructures. In one case, a user moves from one subnet to another, while moving from one subnet gateway to the next. The new gateway does not host the original subnet. In another, the user moves from an original VLAN to a new VLAN, for instance going from an original access point to a new access point. The gateway may or may not change. These cases present different problems because of the different network access protocols involved.
An opportunity arises to develop mobility support that is transparent to existing devices, that does not require rewriting the kernel or stack to support a new IP architecture, and responds to mobility without changing the client machine's assigned IP address. It is bound to be easier to add features to devices that support mobility across a campus than to change all of the devices that users carry. Better, more easily configured and controlled, more resilient and transparent components and systems may result.

Methods and devices to support mobility of a client across VLANs and subnets, while preserving the client's assigned IP address


A novel amino resin composition produced by reacting one of or a mixture of more than two triazine derivatives of Formula I: ##STR1## wherein, R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5 and R.sup.6 each represent an independent substituent, and one to five substituents thereof represent a C.sub.1 -.sub.20 alkyl group, a C.sub.2-20 alkenyl group (the alkyl group or alkenyl group may optionally have an alicyclic structure of phenyl group), or a phenyl group, and the remaining substituent or substituents represent a hydrogen atom with formaldehyde; a novel amino composition produced by reacting a mixture of one of or a mixture of more than two of said triazine derivatives and melamine or urea with formaldehyde; and an amino composition comprising a novel amino composition produced by reacting a mixture of one of or a mixture of more than two triazine derivatives with formaldehyde and a melamine-formaldehyde resin and a melamine/urea-formaldehyde resin or a urea-formaldehyde resin. The amino resin compositions have toughness, post-formability, heat resistance, high hardness and excellent gloss so that they are usable for laminated sheets, decorative sheets, molding compounds, and so on. Further, the compositions can be improved in solubility in organic solvents and liphophilicity by selecting substituents, and therefore are also usable in the fields of coatings and adhesives.

A malamine resin has been conventionally and widely employed as a molding compound, a facing material, a curing agent for coatings, and an adhesive for woody materials, etc. because of excellent heat resistance, high hardness, high gloss, quick curability, and an excellent mold release property in molding.
On the other hand, melamine is hexa-functional, and a triazine skelton is rigid. Accordingly, a crosslinking density in a cured product therefrom becomes exceedingly high in a case of preparing a resin with formaldehyde, whereby it is very hard and excellent in heat resistance. Contrarily, however, it is brittle, and there has been limitation in a case that the molding compound is employed as industrial parts.
For that reason, in a case that it is employed as molding compound, it has been attempted that the melamine resin has been modified by a rubber or phenol. However, a sufficient effect has not been obtained in the existing circumstances. Further, although the addition of various kinds of alcohols and saccharides into a melamine resin composition has been attempted for improving crack resistance and mechanical strength. However, in a case that co-condensation has not been sufficient in the preparation, there has been drawbacks to cause a decline of mechanical strength, a decline of crack resistance, and a decline of glossiness in surface because additives cause bleedout with a lapse of time.
Still further, the melamine resin in mainly employed in a baking coating as a curing agent for an alkyd resin, and it is excellent in heat resistance, light resitance, and resistance to scratching. On the other hand, it is poor in bending ability of a coating layer and post processability. For that reason, guanamines such as benzoguanamine and acetoguanamine are occasionally employed. However, benzoguanamine resin has benzene group in the structure and accordingly, it has been known that it in poor in light resistance and thus, it is limited in utilization. Also, a melamine-formaldehyde resin is poor in solubility in organic solvents and, for that reason, in the case that it is employed as an organic solvent-based coating, a melamine-formaldehyde reaction product has been dissolved into solvents by further alkoxylation with alcohols such as methanol, ethanol, propanol, isopropanol, and butanol. However, alkoxylation reaction has drawbacks that it requires a long time in reaction steps and that as the alkoxylation reaction in conducted in acidic condition, condensation is accelerated and thus, it becomes difficult in controlling a molecular weight.
The melamine resin has been conventionally and mainly employed as a facing material for a horizontal decorated surface in a furniture due to a high hardness, a high heat resistance, and high gloss. In recent years, so-called post-forming processing is frequently put into practice, in which a decorative laminated sheet is post-processed after curing in order to promote features as a design.
Whereas a decorative melamine laminated sheet has a high hardness, cracks are occasionally caused with a lapse of time. Therefore, the improvements in that point have been tried.
For the purpose, it has been conducted an improvement for modifying a melamine resin using various kinds of compounds having copolycondensation, or adding various kinds of additives to the melamine resin so as to improve the post-forming processing property and for crack resistance. however, when an incorporation of the compounds or additives into the resin is poor, water resistance and gloss are lowered. Thus, it can not be necessarily said that sufficient results have been obtained.
Melamine has been frequently employed as adhesives for woody materials in combination with urea. Although it is excellent in processability due to a quick curing rate compared to a phenolic resin adhesive employed in the same kinds of uses, it is disadvantageous to be used to resinous needle-leaf trees which have been often employed in recent years since a melamine resin adhesive itself is poor in a lipophilic nature.
The prevent invention provides an amino resin composition having toughness, bending processability, and a lipophilic nature without a loss of properties such as heat resistance, high hardness, and excellent gloss in the melamine resin.


A coaxial connector for connection with a coaxial cable has an insulative sleeve, a connection member, and a conductive terminal. The connection member is a tubular conductive structure. The insulative sleeve is positioned in the connection member. The connection member has an inscribed surface formed at a rear end thereof. The conductive terminal has a positioning recess formed at a rear end thereof for soldering with a core of the coaxial cable. A conductive layer of the coaxial cable is penetrated into the rear end of the connection member and is adjacent to the inscribed surface for soldering with the connection member. Therefore, the connection between the coaxial cable and the coaxial connector is easy, and the position of the coaxial cable is accurate. Moreover, because it is not necessary to spread the conductive layer of the coaxial cable, it maintains a better electrical property, so as to have a broad application, a wide range of frequency, and a high stability and small loss of signals thereof.

It is well known that coaxial cables are commonly used in communication equipment. The trend of development of both hardware and software of electronic products, such as notebook computers, is to combine the notebook computers with mobile communication functions. A coaxial cable is applied to connect with a built-in antenna to a communication module on a printed circuit board of a notebook. A distal end of the coaxial cable connects to a mating connector of the communication module or a mating connector disposed at a distal end of another coaxial cable by using a coaxial connector.
Referring to FIG. 1 and FIG. 2, a conventional coaxial connector (such as MicroMate Coax Connector, MMCX) is for connection with a coaxial cable 5. The coaxial cable 5 has a core 50, an inner insulative layer 51, a conductive layer 52, and an outer insluative layer 53 arranged from an inside thereof to an outside thereof in order. The conductive layer 52 is a metal braid. The coaxial connector includes an insulative sleeve 6, a connection member, and a conductive terminal 4. The connection member is a tubular conductive structure and has a body element 7, an extension element 8, and a resilient snap-ring 9. The body element 7 has a front opening 70 and a rear opening 71 respectively formed at a front end thereof and a rear end thereof. The insulative sleeve 6 is installed in the body element 7 through the rear opening 71. The extension element 8 has a front end connecting in the rear opening 71 of the body element 7 and positioning the insulative sleeve 6 in the connection member. The extension element 8 has a circumscribed surface 80 disposed at an outer surface of a rear end thereof. The resilient snap-ring 9 snaps around an outer circumferential surface of the front end of the body element 7. The conductive terminal 4 is a male terminal and has a positioning recess 411 formed at a rear end thereof.
When the coaxial cable 5 is connected with the coaxial connector, first, a rivet element 57 is disposed around the coaxial cable 5, and a distal end of the coaxial cable 5 is stripped to expose the core 50, the inner insulative layer 51, and the conductive layer 52. Next, the core 50 of the coaxial cable 5 is penetrated into the positioning recess 411 and is soldered on the conductive terminal 4, and the conductive layer 52 is spread. Further, a front end of the conductive terminal 4 is penetrated through the extension element 8, the inner insulative layer 51 is located in the extension element 8, and the conductive layer 52 of the coaxial cable 5 envelops the circumscribed surface 80 of the extension element 8. Further, the front end of the conductive terminal 4 is penetrated through the insulative sleeve 6 to a front end of the connection member, and a front end of the extension element 8 is connected in the rear opening 71 of the body element 7. Finally, the rivet element 57 is disposed outside the conductive layer 52, and a set of hexagonal molds is applied to rivet the rivet element 57, so as to fix the conductive layer 52 on the extension element 8 of the connection member.
According to the conventional coaxial connector, first, because the conductive layer 52 is spread, a specific electrical property is formed, and the coaxial connector can only be applied to one type of an outer diameter of the coaxial cable and the range of frequency is only in DC-6 Ghz. Second, the conductive layer 52 is spread, so the stability thereof is impacted and it causes loss of signals thereof. Third, it is time-consuming and hard to position to spread the conductive layer 52 and to dispose the conductive terminal 4. Moreover, when the set of hexagonal molds rivets the rivet element 57, a shearing force is produced to push the conductive terminal 4 backwardly. As a result, the position of the conductive terminal 4 is not accurate.
FIG. 3 and FIG. 4 show another conventional coaxial connector which is a mating connector of the coaxial connector described in FIG. 1 and FIG. 2. The way to connect the coaxial connector in FIG. 3 and FIG. 4 with the coaxial cable 5 is the same as above. The differences of the structure are that the conductive terminal 4′ is a female terminal, and the body element 7′ has a front opening 70′ formed at a front end thereof and an inner groove 72′. When the above two coaxial connectors are mated with each other, the resilient snap-ring 9 is locked in the inner groove 72′ to ensure the mating stability. Though it reaches the required stability, the insertion or pulling force of the mating or detachment thereof is above 10 pounds, which is hard to do by hands.
Accordingly, as discussed above, the conventional coaxial connector still has some drawbacks that could be improved. The present invention aims to resolve the drawbacks in the prior art.


A machining system having a machining envelope, a housing, a hopper, and a seal. The housing defines at least a portion of the machining envelope. The hopper has a top surface defining an opening. The seal is disposed between the housing and the top surface. The hopper is configured to receive particulates when positioned below the machining envelope.

1. Field of the Invention
The present invention relates to a machining system having a hopper adapted to receive particulates, such as chips.
2. Background Art
Previously, machine tools used coolant to flush chips from workpiece and machine tool surfaces. Chips were removed from the coolant using a filtration system that deposited chips on an indexable media and dumped the deposited chips into a chip hopper. In such systems the filtration system and chip hopper were located apart from the machine tool. Consequently, these systems required expensive coolant filtration systems as well as coolant handling equipment to transport chips from the machine tool to the filtration system. In addition, such systems did not help contain airborne particulates, such as oil mist. As a result, air filtration equipment was needed to improve air quality.
Before Applicants' invention, a system for containing particulates, such as oil mist and chips, without the need for coolant, coolant filtration equipment, and air filtration equipment was needed. Problems associated with the prior art as noted above and other problems are addressed by Applicants' invention as summarized below.

Machining system with integrated chip hopper


A switching regulator for controlling transmit antennas of variable impedance, particularly transmit antennas of a keyless access authorization system in or for a vehicle, having an input terminal into which an antenna potential applied or appliable at the transmit antenna may be coupled, and having a control circuit designed to generate a compensation signal as a controlled variable for adapting the antenna potential to an actual output impedance and to establish a slope of the compensation signal depending on the actual antenna potential. The invention relates furthermore to a transceiver circuit with such a switching regulator and to a keyless access control system in or for a vehicle.

1. Field of the Invention
The present invention relates to a switching regulator for controlling transmit antennas of variable impedance, particularly transmit antennas of a keyless access authorization system in or for a vehicle, a transceiver circuit having a switching regulator of this type, and a keyless access control system in or for a vehicle.
2. Description of the Background Art
The invention and its underlying problem are described hereafter with reference to a keyless access control system in a motor vehicle, however, without limiting the invention thereto. It is pointed out in particular that the invention may certainly also be used in other applications, for example, in switching power supplies.
Modern electronic anti-theft systems in a motor vehicle comprise an access authorization system, for example, a central locking device that can be activated by a mechanical or electronic key. Modern access authorization systems in motor vehicles enable in addition or alternatively keyless access as well. This type of system is, for example, the keyless access system with the name "Adrima" that was developed and sold by the company ATMEL Germany GmbH and works with a so-called passive access control system ("passive access"). In the passive access control system, a question-answer dialog is initiated when a user approaches his motor vehicle. In this case, a request signal is transmitted by a transmitter with a transmit antenna in the vehicle to a transponder carried by the user. When said transponder receives the request signal, it transmits, e.g., a cryptologically encoded response signal. In the motor vehicle, this response signal is received by means of a receive antenna, decoded, and compared with an expected set signal. If the response signal and set signal match, i.e., in the case of a successful authentication, the doors and optionally also the anti-theft device are unlocked.
The German patent DE 195 46 171 C1, which corresponds to U.S. Pat. No. 5,838,074, describes this type of anti-theft system for use in a motor vehicle, in which bidirectional data communication is established by means of magnetic coupling between a vehicle-side transceiver and a mobile transponder. The data communication occurs by turning on and off an alternating field generated magnetically by the transceiver according to the data to be transmitted. For this purpose, the transceiver has an inductive antenna resonant circuit, which is excited by a drive circuit. The inductor of the transceiver antenna resonant circuit is coupled magnetically to a corresponding inductor of the transponder antenna resonant circuit.
A system for passive access control may have, e.g., a control device in the vehicle and typically several inductive antennas, which are distributed in the vehicle and are connected to the control device via connecting lines generally of different lengths. These inductive antennas are activated by a switching regulator within the control device. It is problematic here that as the length of the connecting lines increases, their parasitic capacitances and inductances also increase, so that these are no longer negligible. In addition to this self-capacitance and self-inductance of the connecting lines, a capacitive fraction is also to be considered that results from the type and installation of the connecting lines in the vehicle, for example, from the effect of the vehicle body.
Another problem results from the type of transmit antennas, which ideally are to be made as identical as possible, but which in the specific technical implementation, e.g., due to the employed production technology, in fact have a more or less broad variation in the antenna impedance.
The control of the plurality of antennas is problematic here. Typically, the control device has a switching regulator for controlling all transmit antennas within the motor vehicle. The switching regulator and the output driver connected to the switching regulator are designed to control all transmit antennas of a motor vehicle with a predefined signal level that is as identical as possible, whereby a minor voltage or current fluctuation can be compensated by the switching regulator. Because of the at times highly varying antenna impedances, however, the current flowing through the different antennas also fluctuates and thereby accordingly greatly also the dropping voltage at the transmit antenna. Particularly in the vehicle sector, the antenna impedance can vary by up to several 10 ohms, so that the antenna current to be driven by the control amplifier through the antennas can vary as a result by up to several amperes. This means that the switching regulator must be designed to ensure a control stability over a relatively large load range. The switching regulator must therefore be designed to be able to switch output voltages in the range from a few volts to several 10 volts.
The particular problem here is that the switching regulator can thereby become unstable in its control stability, which overall has the result that a functioning control is no longer assured. There is the need therefore to provide a switching regulator that can regulate as precisely as possible the output voltage provided for the antenna and thereby the antenna current also during highly varying input voltages.
U.S. Pat. No. 5,903,452 describes a switching regulator with a control circuit that provides a compensation signal for regulation. The voltage ramp of the compensation signal in this case depends on a coil current tapped directly at the antenna coil and fed back, so that the regulation here is based directly on the coil current.

Switching regulator, transceiver circuit, and keyless access control system


A dishwasher method and apparatus providing an algorithm varying the speed of the recirculation pump that recirculates washing liquor present in the washing compartment so as to assure quiet pump operation is disclosed. The speed of the recirculation pump is varied by a control device that carries out the washing cycle. A true-running monitoring unit checks the operation of the recirculation pump. During a fill phase of the washing cycle, an inlet valve is opened, the recirculation pump is switched on and the algorithm provides stepped variation of the recirculation speed using a default value step, a test step in which a true running check is performed, and a modification step in which the default value is modified in response to the result of the test step, for use in the next iteration of the algorithm.

The present invention relates to a dishwasher, especially a household dishwasher, with a control device for carrying out a washing cycle for cleaning items to be washed, with a washing compartment for accommodating the items to be washed during the washing cycle, with an inlet valve able to be opened and closed by the control device for letting washing liquor into the washing compartment, with a recirculation pump for recirculating the washing liquor present in the washing compartment, the speed of which is able to be varied by the control device and with a true running monitoring unit for checking that the recirculation pump is running true.
Commercially available dishwashers are embodied to automatically fill their washing compartment with washing liquor. Despite a to some extent complex filling process, which as a rule carried out a number of times during a washing cycle, the throughflow quantity of washing liquor is not always dispensed exactly. In addition in a few filling processes undesired noise can be generated while the washing compartment is being filled with washing liquor.

Dishwasher with a dynamic filling sequence


A device for receiving and transporting articles, in particular syringes and the like, of a type comprising a transfer carousel destined to be rotated about a substantially vertical axis peripherally bearing a series of seatings for receiving single articles from a supply station and for transferring the articles to a receiving station. The seatings are fashioned from respective shaped and recessed surfaces realized on respective appendages peripherally associated to the carousel and elastically deformable such as to absorb any variations in size of the articles.

The invention relates to a device for receiving and transporting articles, in particular syringes and the like.
The prior art comprises apparatus which automatically operate the movement of articles of the above-mentioned type, for example during the stage of production or packing. In the mentioned apparatus, devices are usually present for receiving and transporting articles from a first work station to a second work station, such as for example devices which automatically transfer articles under process from a supply carousel located upstream to a receiving carousel located downstream. In particular, devices are known which comprise an essentially circular carousel, rotated about a substantially vertical axis. The carousel peripherally exhibits a series of specially-shaped seatings, destined each to receive a single article collected from the supply station and provided with suitable blocking means for retaining the article in a predetermined position in order to transfer it to the receiving station.
The above-described devices generally efficiently perform the task of transferring the articles from the upstream supply station to the downstream receiving station. It has however been observed that the known devices can be unsuitable for correct use with articles made of a fragile and poorly-deformable material, such as in particular, syringes and the like. Owing to the dimensional tolerances which are determined during manufacture thereof, these articles can exhibit even significantly different dimensions with respect to rated sizes. This can lead to imperfect coupling of the article with the shaped seating destined to contain it on the transfer carousel, with risks of damage or breakage of the article during the receiving and transporting thereof, especially during the most critical stages of the initial loading and the final unloading.
By way of example, FIG. 2 partially illustrates a syringe 5 having a conventional cylindrical shape with an annular edge 15; the manufacturing dimensional tolerances of the syringe 5 are indicated as D±t for the external diameter and R±t for the connecting radius of the annular edge.

Device for receiving and transporting articles


Methods and apparatus for a data transmission in a communication system are disclosed. Each of a subset of plural access terminals desiring to transmit user data in an interval transmits a request to transmit in the interval to an access network. The access network makes a decision to schedule at least one of the subset of the plural access terminals to transmit in the interval in accordance with the request. At least one access point of the access network transmits the decision to the plural access terminals.

1. Field
The present invention relates to communications in a wireline or a wireless communication system. More particularly, the present invention relates to a method and system for a data transmission in such a communication system.
2. Background
Communication systems have been developed to allow transmission of information signals from an origination station to a physically distinct destination station. In transmitting an information signal from the origination station over a communication channel, the information signal is first converted into a form suitable for efficient transmission over the communication channel. Conversion, or modulation, of the information signal involves varying a parameter of a carrier wave in accordance with the information signal in such a way that the spectrum of the resulting modulated carrier wave is confined within the communication channel bandwidth. At the destination station, the original information signal is reconstructed from the modulated carrier wave received over the communication channel. In general, such a reconstruction is achieved by using an inverse of the modulation process employed by the origination station.
Modulation also facilitates multiple-access, i.e., simultaneous transmission and/or reception, of several signals over a common communication channel. Multiple-access communication systems often include a plurality of remote subscriber units requiring intermittent access of relatively short duration rather than continuous access to the common communication channel. Several multiple-access techniques are known in the art, such as time division multiple-access (TDMA), and frequency division multiple-access (FDMA). Another type of a multiple-access technique is a code-division multiple-access (CDMA) spread spectrum system that conforms to the "TIA/EIA/IS-95 Mobile Station-Base Station Compatibility Standard for Dual-Mode Wide-Band Spread Spectrum Cellular System," hereinafter referred to as the IS-95 standard. The use of CDMA techniques in a multiple-access communication system is disclosed in U.S. Pat. No. 4,901,307, entitled "SPREAD SPECTRUM MULTIPLE-ACCESS COMMUNICATION SYSTEM USING SATELLITE OR TERRESTRIAL REPEATERS," and U.S. Pat. No. 5,103,459, entitled "SYSTEM AND METHOD FOR GENERATING WAVEFORMS IN A CDMA CELLULAR TELEPHONE SYSTEM," both assigned to the present assignee.
A multiple-access communication system may be wireless or wire-line and may carry voice traffic and/or data traffic. An example of a communication system carrying both voice and data traffic is a system in accordance with the IS-95 standard, which specifies transmitting voice and data traffic over a communication channel. A method for transmitting data in code channel frames of fixed size is described in detail in U.S. Pat. No. 5,504,773, entitled "METHOD AND APPARATUS FOR THE FORMATTING OF DATA FOR TRANSMISSION", assigned to the present assignee. In accordance with the IS-95 standard, the data traffic or voice traffic is partitioned into code channel frames that are 20 milliseconds wide with data rates as high as 14.4 Kbps. Additional examples of communication systems carrying both voice and data traffic comprise communication systems conforming to the "3rd Generation Partnership Project" (3GPP), embodied in a set of documents including Document Nos. 3G TS 25.211, 3G TS 25.212, 3G TS 25.213, and 3G TS 25.214 (the W-CDMA standard), or "TR-45.5 Physical Layer Standard for cdma2000 Spread Spectrum Systems" (the IS-2000 standard).
The term base station is an access network entity, with which subscriber stations communicate. With reference to the IS-856 standard, the base station is also referred to as an access point. Cell refers to the base station or a geographic coverage area served by a base station, depending on the context in which the term is used. A sector is a partition of a base station, serving a partition of a geographic area served by the base station.
The term "subscriber station" is used herein to mean the entity with which an access network communicates. With reference to the IS-856 standard, the subscriber station is also referred to as an access terminal. A subscriber station may be mobile or stationary. A subscriber station may be any data device that communicates through a wireless channel or through a wired channel, for example fiber optic or coaxial cables. A subscriber station may further be any of a number of types of devices including but not limited to PC card, compact flash, external or internal modern, or wireless or wireline phone. A subscriber station that is in the process of establishing an active traffic channel connection with a base station is said to be in a connection setup state. A subscriber station that has established an active traffic channel connection with a base station is called an active subscriber station, and is said to be in a traffic state.
The term access network is a collection of at least one base station (BS) and one or more base stations' controllers. The access network transports information signals between multiple subscriber stations. The access network may be further connected to additional networks outside the access network, such as a corporate intranet or the Internet, and may transport information signals between each base station and such outside networks.
In the above-described multiple-access wireless communication system, communications between users are conducted through one or more base stations. The term user refers to both animate and inanimate entities. A first user on one wireless subscriber station communicates to a second user on a second wireless subscriber station by conveying information signal on a reverse link to a base station. The base station receives the information signal and conveys the information signal on a forward link to the second subscriber station. If the second subscriber station is not in the area served by the base station, the base station routes the data to another base station, in whose service area the second subscriber station is located. The second base station then conveys the information signal on a forward link to the second subscriber station. The forward link refers to transmissions from a base station to a wireless subscriber station, and the reverse link refers to transmissions from a wireless subscriber station to a base station. Likewise, the communication can be conducted between a first user on a wireless subscriber station and a second user on a landline station. A base station receives the data from the first user on the wireless subscriber station on a reverse link, and routes the data through a public switched telephone network (PSTN) to the second user on a landline station. In many communication systems, e.g., IS-95, W-CDMA, and IS-2000, the forward link and the reverse link are allocated separate frequencies.
Study of voice traffic only services and data traffic only services revealed some substantial differences between the two types of services. One difference concerns delay in delivery of the information content. The voice traffic services impose stringent and fixed delay requirements. Typically, an overall one-way delay of a predetermined amount of voice traffic information, referred to as a speech frame, must be less than 100 ms. In contrast, the overall one-way data traffic delay may be a variable parameter, used to optimize the efficiency of the data traffic services provided by the communication system. For example, multi-user diversity, delay of data transmission until more favorable conditions, more efficient error correcting coding techniques, which require significantly larger delays than delays that can be tolerated by voice traffic services, and other techniques can be utilized. An exemplary efficient coding scheme for data is disclosed in U.S. patent application Ser. No. 08/743,688, entitled "SOFT DECISION OUTPUT DECODER FOR DECODING CONVOLUTIONALLY ENCODED CODEWORDS," filed Nov. 6, 1996, now U.S. Pat. No. 5,933,462, issued Aug. 3, 1999, assigned to the present assignee.
Another significant difference between voice traffic services and data traffic services is that the former require a fixed and common grade of service (GOS) for all users. Typically, for digital communication systems providing voice traffic services, this requirement translates into a fixed and equal transmission rate for all users and a maximum tolerable value for the error rates of speech frames. In contrast, the GOS for data services may be different from user to user, and may be a variable parameter, whose optimization increases the overall efficiency of the data traffic service providing communication system. The GOS of a data traffic service providing communication system is typically defined as the total delay incurred in the transfer of a predetermined amount of data traffic information which may comprise, e.g., a data packet. The term packet is a group of bits, including data (payload) and control elements, arranged into a specific format. The control elements comprise, e.g., a preamble, a quality metric, and others known to one skilled in the art. Quality metric comprises, e.g., a cyclic redundancy check (CRC), a parity bit, and others known to one skilled in the art.
Yet, another significant difference between voice traffic services and data traffic services is that the former requires a reliable communication link. When a subscriber station, communicating voice traffic with a first base station, moves to the edge of the cell served by the first base station, the subscriber station enters a region of overlap with another cell served by a second base station. The subscriber station in such a region establishes a voice traffic communication with the second base station while maintaining a voice traffic communication with the first base station. During such a simultaneous communication, the subscriber station receives a signal carrying identical information from two base stations. Likewise, both of the base stations also receive signals carrying information from the subscriber station.
Such a simultaneous communication is termed soft handoff. When the subscriber station eventually leaves the cell served by the first base station, and breaks the voice traffic communication with the first base station, the subscriber station continues the voice traffic communication with the second base station. Because soft handoff is a "make before break" mechanism, the soft-handoff minimizes the probability of dropped calls. A method and system for providing a communication with a subscriber station through more than one base station during the soft handoff process are disclosed in U.S. Pat. No. 5,267,261, entitled "MOBILE ASSISTED SOFT HAND-OFF IN A CDMA CELLULAR TELEPHONE SYSTEM," assigned to the present assignee.
Softer hand-off is a similar process whereby the communication occurs over at least two sectors of a multi-sector base station. The process of softer handoff is described in detail in U.S. patent application Ser. No. 08/763,498, entitled "METHOD AND APPARATUS FOR PERFORMING HAND-OFF BETWEEN SECTORS OF A COMMON BASE STATION," filed Dec. 11, 1996, now U.S. Pat. No. 5,933,787, issued on Aug. 3, 1999, assigned to the present assignee. Thus, both soft and softer handoff for voice services result in redundant transmissions from two or more base stations to improve reliability.
This additional reliability is not so important for data traffic communications because the data packets received in error can be retransmitted. Important parameters for data services are transmission delay required to transfer a data packet and the average throughput rate of the data traffic communication system. The transmission delay does not have the same impact in data communication as in voice communication, but the transmission delay is an important metric for measuring the quality of the data communication system. The average throughput rate is a measure of the efficiency of the data transmission capability of the communication system. Because of relaxed transmission delay requirement, the transmit power and resources used to support soft handoff on the forward link can be used for transmission of additional data, thus, increasing average throughput rate by increasing efficiency.
The situation is different on the reverse link. Several base stations can receive the signal transmitted by a subscriber station. Because re-transmission of packets from a subscriber station requires additional power from a power limited source (a battery), it may be efficient to support soft handoff on the reverse link by allocating resources at several base stations to receive and process the data packets transmitted from the subscriber station. Such a utilization of soft handoff increases both coverage and reverse link capacity as discussed in a paper by Andrew J. Viterbi and Klein S. Gilhdusen: "Soft Handoff Increases CDMA coverage and Increases Reverse Link Capacity," IEEE Journal on Selected Areas in Communications, Vol. 12, No. 8, October 1994. The term soft hand-off is a communication between a subscriber station and two or more sectors, wherein each sector belongs to a different cell. In the context of the IS-95 standard, the reverse link communication is received by both sectors, and the forward link communication is simultaneously carried on the two or more sectors' forward links. In the context of the IS-856 standard, data transmission on the forward link is non-simultaneously carried out between one of the two or more sectors and the access terminal. Additionally, a softer handoff, may be used for this purpose. The term softer handoff is a communication between a subscriber station and two or more sectors, wherein each sector belongs to the same cell. In the context of the IS-95 standard, the reverse link communication is received by both sectors, and the forward link communication is simultaneously carried on one of the two or more sectors' forward links. In the context of the IS-856 standard, data transmission on the forward link is non-simultaneously carried out between one of the two or more sectors and the access terminal.
It is well known that quality and effectiveness of data transfer in a wireless communication system is dependent on the condition of a communication channel between a source terminal and a destination terminal. Such a condition, expressed as, for example, a signal-to-interference-and-noise-ratio (SINR), is affected by several factors, e.g., a path loss and the path loss' variation of a subscriber station within a coverage area of a base station, interference from other subscriber stations both from the same-cell and from other-cell, interference from other base stations, and other factors known to one of ordinary skill in the art. In order to maintain a certain level of service under variable conditions of the communication channel, TDMA and FDMA systems resort to separating users by different frequencies and and/or time-slots and support frequency reuse to mitigate the interference. Frequency reuse divides an available spectrum into many sets of frequencies. A given cell uses frequencies from only one set; the cells immediately adjacent to this cell may not use a frequency from the same set. In a CDMA system, the identical frequency is reused in every cell of the communication system, thereby improving the overall efficiency. The interference is mitigated by other techniques, e.g., orthogonal coding, transmission power control, variable rate data, and other techniques known to one of ordinary skill in the art.
The above-mentioned concepts were utilized in a development of a data traffic only communication system known as the High Data Rate (HDR) communication system. Such a communication system is disclosed in detail in application Ser. No. 08/963,386, entitled "METHOD AND APPARATUS FOR HIGH RATE PACKET DATA TRANSMISSION," filed Nov. 3, 1997, now U.S. Pat. No. 6,574,211, issued on Jun. 3, 2003, assigned to the present assignee. The HDR communication system was standardized as a TIA/EIA/IS-856 industry standard hereinafter referred to as the IS-856 standard.
The IS-856 standard defines a set of data rates, ranging from 38.4 kbps to 2.4 Mbps, at which an access point (AP) may send data to a subscriber station (access terminal). Because the access point is analogous to a base station, the terminology with respect to cells and sectors is the same as with respect to voice systems. In accordance with the IS-856 standard, the data to be transmitted over the forward link are partitioned into data packets, with each data packet being transmitted over one or more intervals (time-slots), into which the forward link is divided. At each time-slot, data transmission occurs from an access point to one and only one access terminal, located within the coverage area of the access point, at the maximum data rate that can be supported by the forward link and the communication system. The access terminal is selected in accordance with forward link conditions between the access point and an access terminal. The forward link conditions depend on interference and path loss between an access point and an access terminal, both of which are time-variant. The path loss and the variation of the path loss are exploited by scheduling the access point's transmissions at time intervals, during which the access terminal's forward link conditions to a particular access point satisfy determined criteria that allow for transmissions with less power or higher rate of data than transmissions to the remaining access terminals, thus improving spectral efficiency of forward link transmissions.
In contrast, according to the IS-856 standard, data transmissions on the reverse link occur from multiple access terminals located within a coverage area of an access point. Furthermore, because the access terminals' antenna patterns are omni-directional, any access terminal within the coverage area of the access point may receive these data transmissions. Consequently, the reverse link transmissions are subjected to several sources of interference: code-division multiplexed overhead channels of other access terminals, data transmissions from access terminals located in the coverage area of the access point (same-cell access terminals), and data transmissions from access terminals located in the coverage area of other access points (other-cell access terminals).
With the development of wireless data services, the emphasis has been on increasing data throughput on the forward link, following the model of Internet services; where a server provides high rate data in response to requests from a host. The server-to-host direction is akin to a forward link requiring a high throughput, while the host-to-server requests and/or data transfers are at lower throughput. However, present developments indicate a growth of reverse link data intense applications, e.g., file transfer protocol (FTP), video conferencing, gaming, constant bit rate services, and the like. Such applications require improved efficiency of the reverse link to achieve higher data rates, so that applications demanding high throughput over reverse link. Therefore, there is a need in the art to increase data throughput on the reverse link, ideally to provide symmetric forward and reverse links throughputs. The increased data throughput on the reverse link further creates need in the art for method and apparatus for a power control and a rate of data determination.
The above and further features of the invention are set forth with particularity in the appended claims and together with advantages thereof will become clearer form considerations of the following detailed description of embodiments of the invention given by way of example with reference to the accompanying drawings.

Method and system for a data transmission in a communication system


The present invention provides a plurality of representations of color that are stored in an electronic color library and that can be selected by a user. After a color selection is made, a plurality of color ink formulas and/or colorant formulas capable of producing the selected color are provided. Further, other selections can be made to define a substrate or other criteria that can impact the color ink formulas. The user can make a selection among the plurality of color ink formulas and/or colorant formulas. The selected color ink formula (s) (or colorant formula (s)) can be transmitted over a communication network, such as the Internet or a local Intranet to another party, such as an ink manufacturer.

The present invention relates to a system and method for electronically communicating, coordinating and disseminating formula data for the production of color ink between a plurality of parties.
Electronic color production hardware and software systems currently exist which separately and independently perform tasks associated with production of color-related products. For example, a known system reads a visible spectrum of a color sample and generates data regarding measured amounts of light absorbed or reflected at particular points in the spectrum. Any given color has a spectral curve associated with it that functions as a signature of the color. Once a spectral curve is determined, the visible spectrum and coefficients are then processed to predict a color formula for reproducing the color. The color formula can then be analyzed to create a color ink formula for creating a color.
Other common color representations exist, for example RGB represents the degree of red, green and blue in a color. CMYK represents the degree of cyan, magenta, yellow and black in a given color. Accurate translation between color representations, for example a translation from RGB to CMYK for computer monitors and computer printers is provided. Accurate color reproduction is achieved, in part, by retrieving data for a plurality of input and output devices, e.g., printers, monitors, and color measuring devices, and modifying the color translation formulas to account for the specific devices receiving the data. Computer software design packages, such as ADOBE ILLUSTRATOR and PAGEMAKER, provide such conversion functionality. Another known system provides a method and apparatus for accurately matching colors. For example, spectral data are received from a color measuring device and the corresponding color is matched in an electronic color library. The desired color is compared to colors stored in the electronic color library and the color or colors in the library that are within a specified color range are reported. By searching in an electronic library, the traditional standard color swatch book used for locating a desired color is replaced. This electronic color library is vulnerable, however, to problems associated with reproducing samples from multiple devices.
Another method involves receiving a communication of the designer's computer image and converting the RGB setting to CIELAB values. Computer software design packages such as ADOBE PHOTOSHOP provide such conversion functionality.
Currently, methods exist for defining color ink formulas for making ink suitable for creating a particular color. However, no suitable system is available which enables, for example, a designer of color-related products to identify a color and a particular substrate, and to automatically generate a color ink formula suitable for creating the color on the substrate, which can be transmitted automatically to another party, for example an ink manufacturer.

System and method for disseminating color ink and colorant formulas


The present invention is directed to a new composition for performing a nucleic acid amplification reaction comprising (i) a thermostable DNA-Polymerase, (ii) a thermostable 3′-5′ Exonuclease, and (iii) at least one primer for nucleic acid amplification with a modified 3′ terminal residue which is not elongated by said thermostable DNA-Polymerase as well as methods for performing a PCR reaction using this composition. Furthermore, the method is directed to kits comprising such a composition.

In vitro nucleic acid synthesis is routinely performed with DNA polymerases with or without additional polypeptides. DNA polymerases are a family of enzymes involved in DNA replication and repair. Extensive research has been conducted on the isolation of DNA polymerases from mesophilic microorganisms such as E. coli. See, for example, Bessman et al., J. Biol. Chem. 223 (1957) 171–177, and Buttin, G. and Kornberg, A., J Biol Chem 241 (1966) 5419–27.
Research has also been conducted on the isolation and purification of DNA polymerases from thermophiles, such as Thermus aquaticus. Chien, A., et al., J Bacteriol 127 (1976) 1550–7 discloses the isolation and purification of a DNA polymerase with a temperature optimum of 80° C. from Thermus aquaticus YT1 strain. U.S. Pat. No. 4,889,818 discloses a purified thermostable DNA polymerase from T. aquaticus, Taq polymerase, having a molecular weight of about 86,000 to 90,000 daltons. In addition, European Patent Application 0 258 017 discloses Taq polymerase as the preferred enzyme for use in the PCR process.
Research has indicated that while Taq DNA polymerase has a 5′-3′ polymerase-dependent exonuclease function, Taq DNA polymerase does not possess a 3′-5′ exonuclease function (Lawyer, F. C., et al., J Biol Chem 264 (1989) 6427–37; Bernad, A., et al., Cell 59 (1989) 219–28). The 3′-5′ exonuclease activity of DNA polymerases is commonly referred to as "proofreading activity". The 3′-5′ exonuclease activity removes bases which are mismatched at the 3′ end of a primer-template duplex. The presence of 3′-5′ exonuclease activity may be advantageous as it leads to an increase in fidelity of replication of nucleic acid strands and to the elongation of prematurely terminated products. As Taq DNA polymerase is not able to remove mismatched primer ends it is prone to base incorporation errors, making its use in certain applications undesirable. For example, attempting to clone an amplified gene is problematic since any one copy of the gene may contain an error due to a random misincorporation event. Depending on the cycle in which that error occurs (e.g., in an early replication cycle), the entire DNA amplified could contain the erroneously incorporated base, thus, giving rise to a mutated gene product.
There are several thermostable DNA polymerases known in the art which exhibit 3′-5′exonuclease activity, like B-type polymerases from thermophilic Archaebacteria which are used for high fidelity DNA amplification. Thermostable polymerases exhibiting 3′-5′exonuclease activity may be isolated or cloned from Pyrococcus (Purified thermostable Pyrococcus furiosus DNA polymerase, Mathur E., Stratagene, WO 92/09689, U.S. Pat. No. 5,545,552; Purified thermostable DNA polymerase from Pyrococcus species, Comb D. G. et al., New England Biolabs, Inc., EP 0 547 359; Organization and nucleotide sequence of the DNA polymerase gene from the archaeon Pyrococcus furiosus, Uemori, T., et al., Nucleic Acids Res 21 (1993) 259–65), from Pyrodictium spec. (Thermostable nucleic acid polymerase, Gelfand D. H., F. Hoffmann-La Roche AG, EP 0 624 641; Purified thermostable nucleic acid polymerase and DNA coding sequences from Pyrodictium species, Gelfand D. H., Hoffmann-La Roche Inc., U.S. Pat. No. 5,491,086), from Thermococcus (e.g. Thermostable DNA polymerase from Thermococcus spec. TY, Niehaus F., et al. WO 97/35988; Purified Thermocccus barossii DNA polymerase, Luhm R. A., Pharmacia Biotech, Inc., WO 96/22389; DNA polymerase from Thermococcus barossii with intermediate exonuclease activity and better long term stability at high temperature, useful for DNA sequencing, PCR etc., Dhennezel O. B., Pharmacia Biotech Inc., WO 96/22389; A purified thermostable DNA polymerase from Thermococcus litoralis for use in DNA manipulations, Comb D. G., New England Biolabs, Inc., U.S. Pat. No. 5,322,785, EP 0 455 430; Recombinant thermostable DNA polymerase from Archaebacteria, Comb D. G., New England Biolabs, Inc., U.S. Pat. No. 5,352,778, EP 0 547 920, EP 0 701 000; New isolated thermostable DNA polymerase obtained from Thermococcus gorgonarius, Angerer B. et al. Boehringer Mannheim GmbH, WO 98/14590).
Another possibility of conferring PCR in the presence of a proofreading function is the use of a mixture of polymerase enzymes, one polymerase exhibiting such a proofreading activity. (e.g. Thermostable DNA polymerase with enhanced thermostability and enhanced length and efficiency of primer extension, Barnes W. M., U.S. Pat. No. 5,436,149, EP 0 693 078; Novel polymerase compositions and uses thereof, Sorge J. A., Stratagene, WO 95/16028). It is common practice to use a formulation of a thermostable DNA polymerase comprising a majority component of at least one thermostable DNA polymerase which lacks 3′-5′ exonuclease activity and a minority component exhibiting 3′-5′ exonuclease activity e.g. Taq polymerase and Pfu DNA polymerase. In these mixtures the processivity is conferred by the pol I-type enzyme like Taq polymerase, the proofreading function by the thermostable B-type polymerase like Pfu.
High fidelity DNA synthesis is one desirable parameter in nucleic acid amplification, another important feature is the possibility of decontamination. The polymerase chain reaction can amplify a single molecule over a billionfold. Thus, even minuscule amounts of a contaminant can be amplified and lead to a false positive result. Such contaminants are often poducts from previous PCR amplifications (carry-over contamination). Therefore, researchers have developed methods to avoid such a contamination. The procedure relies on substituting dUTP for TTP during PCR amplification to produce uracil-containing DNA (U-DNA). Treating subsequent PCR reaction mixtures with Uracil-DNA-Glycosylase (UNG) prior to PCR amplification the contaminating nucleic acid is degraded and not suitable for amplification. dUTP can be readily incorporated by poll-type thermostable polymerases but not B-type polymerases (Slupphaug, G., et al., Anal Biochem 211 (1993) 164–9) Low incorporation of dUTP by B-type polymerases limits their use in laboratories where the same type of template is repeatedly analyzed by PCR amplification.
Thermostable DNA polymerases exhibiting 3′-5′exonuclease activity were also isolated from eubacterial strains like Thermotoga (Thermophilic DNA polymerases from Thermotoga neapolitana, Slater M. R. et al. Promega Corporation, WO 96/41014; Cloned DNA polymerases from Thermotoga neapolitana and mutants thereof, Hughes A. J. et al., Life Technologies, Inc. WO 96/10640; Purified thermostable nucleic acid polymerase enzyme from Termotoga maritima, Gelfand D. H. et al., CETUS Corporation, WO 92/03556) These enzymes have a strong 3′-5′exonuclease activity which is able to eliminate misincorporated or mismatched bases. A genetically engineered version of this enzyme is commercially availabile as ULTma, a DNA polymerase which can be used without additional polypeptides for the PCR process. This enzyme is able to remove misincorporated bases, incorporate dUTP, but the fidelity is for unknown reasons not higher than that of Taq polymerase (Accuracy of replication in the polymerase chain reaction. Diaz, R. S. and Sabino, E. C., Braz J Med Biol Res 31 (1998) 1239–42; PCR fidelity of Pfu DNA polymerase and other thermostable DNA polymerases, Cline, J., et al., Nucleic Acids Res 24 (1996) 3546–51).
There also exists a high fidelity PCR system which is preferably concomitantly able to incorporate dUTP. According to EP-A-1088891, a thermostable enzyme exhibiting 3′-exonuclease-activity but essentially no DNA polymerase activity may be used, which enhances fidelity of an amplification process when added to a second enzyme exhibiting polymerase activity. Thus, the enzyme can excise mismatched primer ends to allow the second enzyme exhibiting polymerase activity as e.g. Taq polymerase to reassociate and to reassume elongation during a process of synthezising DNA. The enzyme needs also to be able to cooperate as proofreading enzyme with a second enzyme exhibiting polymerase activity. Especially suited for this task is e.g. a thermostable exonuclease III. Preferred is an exonuclease III working from the 3′ to 5′ direction, cleaving 5′ of the phosphate leaving 3′ hydroxyl groups and ideally working on double stranded DNA only.
Of course, it is advantageous, if the enzyme is active at 70° C. to 80° C., stable enough to survive the denaturation cycles and inactive at lower temperatures to leave the PCR products undegraded after completion of the PCR process. Enzymes exhibiting these features can be derived from thermophilic eubacteria or related enzymes from thermophilic archaea. Genomes of three thermostable archaebacteria are sequenced, Methanococcus jannaschii (Complete Genome Sequence of the Methanogenic Archaeon, Methanococcus jannaschii, Bult, C. J., et al., Science 273 (1996) 1058–73), Methanobacterium thermoautotrophicum (Complete genomic sequence of Methanobacterium thermoautotrophicum H: Functional Analysis and Comparative Genomics, Smith, D. R., et al., J Bacteriol 179 (1997) 7135–55) and Archaeoglobus fulgidus (The complete genome sequence of the hyperthermophilic, sulfate-reducing archaeon Archaeoglobus fulgidus, Klenk, H. P., et al., Nature 390 (1997) 364–70).
In particular, EP-A-1088891 discloses a thermostable enzyme obtainable from Archaeoglobus fulgidus, which catalyzes the degradation of mismatched ends of primers or polynucleotides in the 3′ to 5′ direction in double stranded DNA. The gene encoding the thermostable exonuclease III obtainable from Archaeoglobus fulgidus (Afu) was cloned, expressed in E. coli and isolated. The enzyme is active under the incubation and temperature conditions used in PCR reactions. The enzyme supports DNA polymerases like Taq in performing DNA synthesis at low error rates and synthesis of products of more than 3 kb on genomic DNA—the upper range of products synthesized by Taq polymerase—in good yields with or without dUTP present in the reaction mixture. Preferably, 50–500 ng of the exonuclease III obtainable from Afu were used per 2.5 U of Taq polymerase in order to have an optimal PCR performance. More preferably is the use of 67 ng to 380 ng of the exonuclease III obtainable from Afu per 2.5 U of the Taq polymerase in the PCR reaction.
Another major problem with nucleic acid amplification and more especially with PCR is the generation of unspecific amplification products. In many cases, this is due to an unspecific oligonucleotide priming and subsequent primer extension event prior to the actual thermocycling procedure itself, since thermostable DNA polymerases are also moderately active at ambient temperature. For example, amplification products due to eventually by chance occuring primer dimerisation and subsequent extension are observed frequently. In order to overcome this problem, it is well known in the art to perform a so called "hot start" PCR, wherein one component essential for the amplification reaction is either separated from the reaction mixture or kept in an inactive state until the temperature of the reaction mixture is being raised for the first time. Since the polymerase cannot function under these conditions, there is no primer elongation during the period when the primers can bind non specifically. In order to achieve this effect, several methods have been applied:
a) Physical Separation of the DNA Polymerase
The physical separation can be obtained for example by a barrier of solid wax, which separates the compartment containing the DNA polymerase from the compartment containing the bulk of the other reagents. During the first heating step the wax is then melting automatically and the fluid compartments are mixed (Chou, Q., et al., Nucleic Acids Res 20 (1992) 1717–23). Alternatively, the DNA polymerase is affinity immobilized on a solid support prior to the amplification reaction and only released into the reaction mixture by a heat mediated release (Nilsson, J., et al., Biotechniques 22 (1997) 744–51). Both methods, however are time consuming and unconvenient to perform.
b) Chemical Modification of DNA Polymerase
For this type of hot start PCR, the DNA polymerase is reversibly inactivated as a result of a chemical modification. More precisely, heat labile blocking groups are introduced into the Taq DNA polymerase which render the enzyme inactive at room temperature. These blocking groups are removed at high temperature during a pre-PCR step such that the enzyme is becoming activated. Such a heat labile modification, for example can be obtained by coupling Citraconic Anhydride or Aconitric Anhydride to the Lysine residues of the enzyme (U.S. Pat. No. 5,677,152). Enzymes carrying such modifications are meanwhile commercially availabile as Amplitaq Gold (Moretti, T., et al., Biotechniques 25 (1998) 716–22) or FastStart DNA polymerase (Roche Molecular Biochemicals). However, the introduction of blocking groups is a chemical reaction which arbitrarily occurs on all sterically available Lysine residues of the enzyme. Therefore, the reproducibility and quality of chemically modified enzyme preparations may vary and can hardly be controlled.
c) DNA Polymerase Inhibition by Nucleic Acid Additives
Extension of non-specifically annealed primers has been shown to be inhibited by the addition of short doublestranded DNA fragments (Kainz, P., et al., Biotechniques 28 (2000) 278–82). In this case, primer extension is inhibited at temperatures below the melting point of the short double stranded DNA fragment, but independent from the sequence of the competitor DNA itself. However, it is not known, to which extent the excess of competitor DNA influences the yield of the nucleic acid amplification reaction.
Alternatively, oligonucleotide Aptamers with a specific sequence resulting in a defined secondary structure may be used. Such Aptamers have been selected using the SELEX Technology for a very high affinity to the DNA polymerase (U.S. Pat. No. 5,693,502), (Lin, Y. and Jayasena, S. D., J Mol Biol 271 (1997) 100–11). The presence of such Aptamers within the amplification mixture prior to the actual thermocycling process itself again results in a high affinity binding to the DNA polymerase and consequently a heat labile inhibition of its activity. Due to the selection process, however, all so far available Aptamers can only be used in combination with one particular species of DNA polymerase.
d) Taq DNA Antibodies
An alternative approach to achieve heat labile inhibition of Taq DNA polymerase is the addition of monoclonal antibodies raised against the purified enzyme (Kellogg, D. E., et al., Biotechniques 16 (1994) 1134–7; Sharkey, D. J., et al., Biotechnology (N Y) 12 (1994) 506–9). Like the oligonucleotide Aptamers, the antibody binds to Taq DNA polymerase with high affinity at ambient temperatures in an inhibitory manner. The complex is resolved in a preheating step prior to the thermocycling process itself. This leads to a substantial time consuming prolongation of the amplification as a whole, especially if protocols for rapid thermocycling are applied (WO 97/46706).
U.S. Pat. No. 5,985,619 discloses a specific embodiment for performing PCR using a hot start antibody, wherein besides Taq polymerase, e.g. Exonuclease III from E. coli is added as a supplement to the amplification mixture in order to digest unspecific primer dimer intermediates. As disclosed above, Exonuclease III recognizes doublestranded DNA as a substrate, like, for example, target/primer- or target/primer extension product hybrids. Digestion is taking place by means of cleavage of the phosphodiester bond at the 5′ end of the 3′ terminal deoxynucleotide residue. Since this type of exonuclease is active at ambient temperatures, all unspecifically annealed primers and primer extension products therefore are digested. This results in some embodiments in an even enhanced specifity of the amplification reaction. Yet, digestion of the unspecific primers dependent on the duration of the preincubation time may lead to a substantial and uncontrolled decrease in primer concentration, which in turn may affect the amplification reaction itself.
e) Usage of Exonucleases
Another alternative for increasing amplification efficiency is the use of phosphorothioate oligonucleotide primers in combination with an exonuclease III in the PCR reaction mixes (EP 0 744 470). In this case, a 3′ exonuclease, which usually accepts double stranded as well as single stranded DNA substrates, degrades duplex artefacts such as primer dimers as well as carry over amplicons, while leaving the single stranded amplification primers undegraded. Similarily, the usage of primers with abasic modified 3′ ends and template dependent removal by E. coli Endonuclease IV has been suggested (U.S. Pat. No. 5,792,607). However, there exist several major draw backs of this methods:
First, oligonucleotides containing phosphorothioate residues can not be synthesized in a stereoisomerically pure manner. Moreover, their hybridisation temperatures are different as compared to unmodified oligonucleotides of the same sequence and unspecific hybridization events are observed frequently.
Second, primers containing phosphorothioate residues even at their 3′ ends can still be elongated by the DNA polymerase, which is already present in the reaction mixture. In other words, the effect of the exonuclease is at least partially compensated by the presence of the polymerase itself.
Third, the enzymatic acitivity of E. coli Endonuclease IV is very low in the presence of Mg++ ions (Siwek, B., et al., Nucleic Acids Res 16 (1988) 5031–8). Yet, dependent on the specific type of assay, an exact significant Mg++ concentration is an essentiall prerequisite for a successful PCR amplification reaction, which renders application of an endonuclease IV in a PCR sample quite ineffective.
Fourth and most important, conventional nucleases like E. coli Exonuclease III or E. coli Endonuclease IV are thermolabile and therefore only active prior to the thermocycling procedure itself. As a consequence, unspecific primer binding and extension is only inhibited prior but not during the temperature cycling process.
In view of the outlined prior art it was an object of the invention to provide an alternative composition and method for hot start PCR, which allows for an inhibition of unspecific priming and primer extension not only prior to the amplification process itself but also during the thermocycling process. More precisely, it was an object of the invention to provide an alternative composition and method for hot start PCR, where no extension of unspecifically annealed primers can take place.

Composition and method for hot start nucleic acid amplification