The present invention is generally directed to systems and methods for monitoring whether an item is properly delivered to a designated delivery point. According to one aspect of the invention, location data and timestamp data is generated in association with the transport and delivery of an item to a delivery point. The location and timestamp data can be compared, respectively, to at least one predetermined geographic boundary that defines a geographic area encompassing the designated delivery point, and to a scheduled time window within which delivery of the item is to occur. This information can be used to determine if a problem has arisen with regard to the transport and delivery of the item to the delivery point. The system is generally configured to generate one or more alerts if it is determined that a particular item has been transported or delivered in an unauthorized manner.

The tremendous volume of goods flowing through a transportation system on any given day creates a significant logistical challenge. As a result, tracking and visibility systems play an integral part in most transportation systems by allowing both customers and transportation personnel to track the flow of goods. However, despite the existence of such prior art systems, items flowing through a transportation system are, on occasion, still delivered to a location later than expected, misdelivered to an incorrect address, and even lost (or stolen) somewhere along the way. These and other such mishaps can be particularly troubling when the items being shipped are considered "high-value" items, based on either their relative importance to the shipper or on their raw economic value. Examples of high-value items can include shipments of diamonds, computer chips, cars or sensitive documents, to name just a few.
For the most part, item tracking services known in the art are passive in the sense that they are generally not designed to actively address the types of problems discussed above. Thus, for example, if an item is lost, stolen, behind schedule, or misdelivered to an incorrect address, such problems may go undetected until a shipper or consignee notices the problem and calls to report it. By then, however, a substantial amount of valuable time may have been lost, during which transportation and security personnel could have been looking into the problem. As such, the likelihood of being able to both diagnose and remedy the cause of any potential problems may have been inadvertently reduced.
Furthermore, while it may sometimes be possible to ship an item via special shipping channels that incorporate more stringent security measures, doing so may not always be desirable. Aside from the obvious fact that shipping the item in such a way can be substantially more expensive, the added security measures can, in some cases, create a new set of problems by drawing unnecessary attention to the item. In other words, by shipping the item via special shipping channels, the shipper may in effect be identifying the item to would-be criminals as a high value item. Thus, in some cases it may actually be safer to at least provide the appearance that the item is being shipped via standard means so that the item blends in and does not stand out as an item of particular value in the various shipping yards, hub locations and other transport points, which the item is likely to pass through.
Therefore, an unsatisfied need exists in the industry for improved systems and methods for monitoring whether an item is properly delivered to a designated delivery point that overcome the deficiencies in the prior art, some of which are discussed above.

Item-based monitoring systems and methods


A method is disclosed for converting light hydrocarbons (e.g. methane or natural gas) to synthesis gas employing a nonmicroporous, thin shell catalyst that catalyzes a net partial oxidation reaction. Certain preferred catalysts comprise a thin outer layer comprising at least one catalytically active metal disposed on a discrete nonmicroporous support structure. A preferred thin shell catalyst has an effectiveness factor greater than 0.1 when utilized in a partial oxidation reaction.

Large quantities of methane, the main component of natural gas, are available in many areas of the world, and natural gas is predicted to outlast oil reserves by a significant margin. However, most natural gas is situated in areas that are geographically remote from population and industrial centers. The costs of compression, transportation, and storage make its use economically unattractive.
To improve the economics of natural gas use, much research has focused on methane as a starting material for the production of higher hydrocarbons and hydrocarbon liquids. The conversion of methane to hydrocarbons is typically carried out in two steps. In the first step, methane is reformed with water to produce carbon monoxide and hydrogen (i.e., synthesis gas or syngas). In a second step, the syngas is converted to hydrocarbons, for example, using the Fischer-Tropsch process to provide fuels that boil in the middle distillate range, such as kerosene and diesel fuel, and hydrocarbon waxes. Present day industrial use of methane as a chemical feedstock typically proceeds by the initial conversion of methane to carbon monoxide and hydrogen by either steam reforming, which is the most widely used process, or by dry reforming. Steam reforming proceeds according to Equation 1.
Although steam reforming has been practiced for over five decades, efforts to improve the energy efficiency and reduce the capital investment required for this technology continue.
The partial oxidation of hydrocarbons, e.g., natural gas or methane is another process that has been employed to produce syngas. While currently limited as an industrial process, partial oxidation has recently attracted much attention due to significant inherent advantages, such as the fact that significant heat is released during the process, in contrast to the steam reforming processes, which are endothermic. Partial oxidation of methane proceeds exothermically according to the following reaction stoichiometry:

In the catalytic partial oxidation (CPOX) processes, natural gas is mixed with air, oxygen or oxygen-enriched air, and is introduced to a catalyst at elevated temperature and pressure. The partial oxidation of methane yields a syngas mixture with a H2:CO ratio of about 2:1, as shown in Equation 2. This ratio is more useful than the H2:CO ratio from steam reforming for the downstream conversion of the syngas to chemicals such as methanol and to fuels. Furthermore, oxidation reactions are typically much faster than reforming reactions. This makes possible the use of much smaller reactors for catalytic partial oxidation processes. The syngas in turn may be converted to hydrocarbon products, for example, fuels boiling in the middle distillate range, such as kerosene and diesel fuel, and hydrocarbon waxes by processes such as the Fischer-Tropsch synthesis.
The selectivities of catalytic partial oxidation to the desired products, carbon monoxide and hydrogen, are controlled by several factors, but one of the most important of these factors is the choice of catalyst composition. Difficulties have arisen in the prior art in making such a choice economical. Typically, catalyst compositions have included precious metals and/or rare earths. The large volumes of expensive catalysts needed by the existing catalytic partial oxidation processes have placed these processes generally outside the limits of economic justification.
A number of process regimes have been described in the literature for the production of syngas via catalyzed partial oxidation reactions. The noble metals, which typically serve as the best catalysts for the partial oxidation of methane, are scarce and expensive. The more widely used, less expensive, catalysts have the disadvantage of promoting coke formation on the catalyst during the reaction, which results in loss of catalytic activity. Moreover, in order to obtain acceptable levels of conversion of gaseous hydrocarbon feedstock to CO and H2 it is typically necessary to operate the reactor at a relatively low flow rate, or space velocity, using a large quantity of catalyst. For successful operation at commercial scale, however, the catalytic partial oxidation process must be able to achieve a high conversion of the methane feedstock at high gas hourly space velocities, and the selectivity of the process to the desired products of carbon monoxide and hydrogen must be high. Such high conversion and selectivity must be achieved without detrimental effects to the catalyst, such as the formation of carbonaceous deposits ("coke") on the catalyst, which severely reduces catalyst performance.
As a result, substantial effort has been devoted in the art to the development of economical catalysts allowing commercial performance without coke formation. Not only is the choice of the catalyst's chemical composition important, the physical structure of the catalyst and catalyst support structures must possess mechanical strength, in order to function under operating conditions of high pressure and high flow rate of the reactant and product gasses.
Of the methods that employ catalysts for oxidative conversion of methane, to syngas, typically catalytic metals are dispersed throughout a porous support. The porous support provides longitudinal channels or passageways that permit high space velocities with a minimal pressure drop. In ideal conditions, the catalytic metals are dispersed throughout the porous channels and promote further conversion.
The use of supports with internal pores can lead to insufficient use of catalyst because (i) the reactants do not have enough time to reach catalytic metals in the pores and (ii) the reactants may become trapped in the pores and interact in undesired secondary reactions during the diffusion of CO and H2 from the pores. Mass transfer rates can indeed control the rate of conversion, especially in short contact reactors.
Accordingly, there is a continuing need for better, more economical processes and catalysts for the catalytic partial oxidation of hydrocarbons, particularly methane, or methane containing feeds, in which the catalyst retains a high level of activity and selectivity to carbon monoxide and hydrogen under conditions of high gas space velocity and elevated pressure.
U.S. Pat. No. 6,281,385 discloses a process for preparing acetic acid by gas-phase oxidation of saturated C4-hydrocarbons and their mixtures with unsaturated C4-hydrocarbons in a tube reactor using a coated catalyst comprising an inert nonporous support body and a catalytically active mixed oxide composition comprising (a) one or more oxides selected from the group consisting of titanium dioxide, zirconium dioxide, tin dioxide and aluminum oxide and (b) from 0.1% to 1.5% by weight, based on the weight of the component (a) and per m2/g of specific surface area of the component (a), of vanadium pentoxide applied to the outer surface of the support body, wherein a gas mixture comprising oxygen or oxygen-containing gas, one or more C4-hydrocarbons and water vapor and having a C4-hydrocarbon/air (oxygen) volume ratio of from 0.2/99.8 to 25/75 and a C4-hydrocarbon/water vapor volume ratio of from 1/1 to 1/60 is reacted over the coated catalyst at a temperature of from 100° C. to 400° C. and a gauge pressure of from 0.2 to 50 bar.
U.S. published application No. 2002/0035033 discloses a process for preparing a shell-type catalyst which comprises applying to a substantially nonporous inorganic support material having a BET surface area of <80 m2/g, a catalytically active outer shell of a suspension containing at least one water soluble noble metal compound and a substantially water insoluble coating compound, drying the suspension onto the support material, and activating the coated support material in a reducing gas stream.
Despite these teachings, there remains a need for a catalyst system that is effective for carrying out fast partial oxidation reactions such as CPOX and oxidative dehydrogenation (ODH).

Use of nonmicroporous support for syngas catalyst


An acceleration sensor. An inertial mass moves inertially when a vehicle suddenly accelerates. A longitudinal direction portion of a trigger lever abuts a portion of a peripheral surface of the inertial mass at a side in a direction of inertial movement thereof. The trigger lever is pushed by the peripheral surface due to inertial movement of the inertial mass, and is rotated around a fulcrum from a first position to a second position. The trigger lever is provided with a trigger means which is located at a position separated by a predetermined distance from the fulcrum and at a position which is different from a position at which the trigger lever abuts the inertial mass. An ignition pin is movable from a non-actuating position at which an occupant protection device is not actuated to an actuating position at which the ignition pin actuates the occupant protection device. The ignition pin has an engaging member. When the trigger lever is at the first position, the engaging member engages with the trigger means so as to position the ignition pin at the non-actuating position. When the trigger lever is moved to the second position, the engaging member cancels engagement of the trigger means and the engaging member so that the ignition pin is movable to the actuating position. An urging means usually urges the ignition pin toward the actuating position.

1. Field of the Invention
The present invention relates to an acceleration sensor in which an actuating member is moved from a non-actuating position to an actuating position, at which the actuating member actuates an occupant protecting device, by inertial movement of an inertial mass which is caused by application of acceleration to the inertial mass when a vehicle suddenly decelerates.
2. Description of the Related Art
An air bag device is known as a device for protecting an occupant of a vehicle.
In an air bag device, when a vehicle suddenly decelerates, an air bag inflates so that an occupant is protected. An acceleration sensor is used to actuate the air bag device when the vehicle suddenly decelerates.
As illustrated in FIG. 5, conventionally, a ball 80 is used as an inertial mass. The ball 80 is provided so as to be able to move inertially when a vehicle suddenly decelerates. When the ball 80 moves inertially, an end portion of the lever 82 ( i.e., the left end portion as illustrated in FIG. 5 ) is pushed toward the front of the vehicle (i.e., in the direction of the FR arrow) by the ball 80. (Hereinafter, the front of the vehicle will be denoted by the FR arrow). The lever 82 rotates around a rotation shaft 84, which is formed so as to project at both end surfaces in the longitudinal direction (i.e., the direction orthogonal to the surface of the paper in FIG. 5) of a trigger member 100 which is provided at a longitudinally intermediate portion of the lever 82.
An ignition pin 86 serving as an actuating member is provided at the longitudinally intermediate portion of the lever 82. The ignition pin 86 is movable, in a direction parallel to the direction of inertial movement of the ball 80, from a non-actuating position, at which an unillustrated detonator is not actuated, to an actuating position, at which the ignition pin 86 ignites the detonator. A bias pin 102, which is urged toward the front of the vehicle by a bias spring 92, abuts the other end portion of the lever 82 (i.e., the right end portion as illustrated in FIG. 5). The bias spring 92 exhibits resistance against inertial movement of the ball 80 caused by deceleration, vibration and the like which are generated under normal running conditions of the vehicle. Therefore, inertial movement of the ball 80 is prevented. Accordingly, the engaging of a trigger portion 90 and an engaging collar 88 of the ignition pin 86 is not canceled, and the ignition pin 86 is not inadvertently moved.
Normally, the engaging collar 88 provided at the longitudinally intermediate portion of the ignition pin 86 is engaged with the trigger portion 90, and the ignition pin 86 is maintained at the non-actuating position, at which the detonator is not actuated. However, when the vehicle suddenly decelerates, the lever 82 is rotated by the inertial movement of the ball 80 towards the front of the vehicle against the urging force of the bias spring 92, and the engagement of the trigger portion 90 and the engaging collar 88 is canceled. Due to this cancellation, the ignition pin 86 is moved by the urging force of an ignition spring 94 toward the actuating position at which the detonator is actuated. The ignition pin 86 abuts the detonator, and the detonator ignites. Due to the ignition of the detonator, a gas-generating material combusts, and gas is generated. The generated gas is supplied to the interior of the air bag, and the air bag inflates.
However, in the above-described conventional acceleration sensor, the bias spring 92 is provided separately from the ignition spring 94 which applies the force for ignition by urging the ignition pin 86 to move to the actuating position. This results in an increased number of structural parts and in troublesome assembly.
Further, in this conventional acceleration sensor, the trigger member 100, at which the trigger portion 90 is formed, is manufactured from a cylindrical member 150 by a number of processes, as can be seen from FIG. 6. Namely, both axial direction end portions of the cylindrical member 150 are cut (i.e., the rotation shaft 84 is formed), a longitudinally intermediate portion of the cylindrical member 150 is cut in order to form the trigger portion 90, a lever insertion hole 102, in which the lever 82 is inserted, is formed, and the like. Further, there is work involved in inserting the lever 82 in the lever insertion hole 102 and work involved in other processes as well. The processing of the trigger member 100 and the number of stages involved in assembly lead to an increase in the manufacturing cost of the conventional acceleration sensor.

Kabushiki Kaisha Tokai-Rika-Denki Seisakusho


A television broadcast signal receiving apparatus includes a receiving unit, a control unit and a display control unit. The receiving unit is configured to receive a plurality of audio-video signals. The control unit is configured to receive operation inputs. The display control unit is configured to display images corresponding to the audio-video signals on a main screen and a subscreen in a display component at the same time. The display control unit is further configured to display an image corresponding to one of the audio-video signals, which has been displayed on the subscreen, on the main screen when the control unit receives an operation input to output audio corresponding to the one of the audio-video signals.

1. Field of the Invention
The present invention generally relates to a television broadcast signal receiving apparatus. More specifically, the present invention relates to a television broadcast signal receiving apparatus displaying a plurality of images.
2. Background Information
A conventional television broadcast signal receiving apparatus has a picture-in-picture (PinP) function or a picture-out-picture (PoutP) function. With the PinP function, one video signal source is displayed on a main screen and another video signal source is displayed on a subscreen. With the PoutP function, screen is divided in two or more and each are displayed separately (see Japanese Laid-Open Patent Application Publication No. 2004-521553, for example).
The conventional television broadcast signal receiving apparatus detects and analyzes main characteristics of a video signal, and arrangements of PinP images varies accordingly. Specifically, image sizes or image locations of the PinP images are varied.
With the conventional television broadcast signal receiving apparatus, the PinP image is prevented from being located over text, faces, or other important objects in the main screen. However, when the user wishes to view the subscreen, the user has to go through a two-step operation. Specifically, first a remote control or other such input device is used to switch the screen by manual operation, and then the volume, etc., is adjusted.
On the other hand, when the volume of a subscreen is adjusted, the subscreen in which the user is interested is still displayed on a smaller screen. Some users find such viewing unappealing.
Also, in the case of PoutP images, if the user plays the audio from a right screen while viewing a left screen, then the audio from the left screen is muted, and the image from the right screen can be viewed. However, since there is no difference in the sizes of the two screens, the viewing experience is not always good for all users.
In view of the above, it will be apparent to those skilled in the art from this disclosure that there exists a need for an improved television broadcast signal receiving apparatus. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure.

Television broadcast signal receiving apparatus


A heating apparatus includes at least first and second burners located in a combustion chamber wherein the burners are separated by a divider for deterring uncombusted fuel flowing from a firing burner to an area adjacent to a non-firing burner. In another aspect of the present invention, the burners are used to heat water in a multiple staged heater.

This invention relates generally to heating apparatuses and more specifically to a multiple stage hot water supply heater.
It is known to provide commercial, gaseous and liquid fossil fuel heaters which use multiple burners in a combustion chamber for heating water. The heated water typically runs through tubes which are also disposed in the combustion chamber. The burners are of a premix air and gas variety, and one or more fans supply air to an air chamber in communication with orifices in the burners.
It is desirable to vary or reduce the firing or burning rate of the burners in order to match the load placed on the appliance. This can be done by varying the input to the burners, by turning off individual burners, or by a combination of modulation and discrete step firing rate reduction. The modulation approach varies the amount of fuel and/or air supplied to the burners rather than turning them only on or off. However, modulation usually requires expensive controls and monitoring equipment to insure safe and efficient operation. Furthermore, it would be very expensive to build an appliance with many individually controlled zones due to the complexity of controls necessary to properly balance the unit for the variable input construction.
The approach of turning off individual burners within one controlled zone upsets the balance but is otherwise fairly economical. The combustion chamber pressure imbalance can force the products of combustion to migrate from the firing burners toward the zones or areas of the non-firing burners and can recirculate back into the path of the fired burners. Thereafter, the products of incomplete combustion are allowed to escape from the unit, past the non-firing burners, which is unacceptable from an environmental emissions standpoint. In other words, the pressure zone above the non-firing burners (i.e., a flame and fuel are not present) is lower than that above the firing burners when one set of burners is not firing. This induces movement of unburned combustion products toward the lower pressure zone. Similarly, the pressure in the area below the non-firing burners can be lower than the areas where the burners are firing. This also induces movement of the uncombusted products from below the firing burners toward the lower pressure zone.


A racking device, for racking a plurality of pool balls upon a pool table have a felt top surface, comprising a rack for containing the balls, a pressure base located above the rack, and a sweeper frame capable of relative vertical movement with respect to the rack. A plurality of sweeper pins extend vertically downward from the sweeper frame, which each selectively engage one of the pool balls. A lever causes the sweeper pins to move downward toward the balls to engage the balls and urge them toward each other. A pressure pin is associated with each of the balls, which firmly press upon the apexes of the balls to press them downward into the felt top surface so that the balls hold their positions in a tight, racked formation even after the racking device has been lifted upward and away from the balls.

The invention relates to a system for racking pool balls on a pool table. More particularly, the invention relates to a racking system that allows players to tightly arrange pool balls in a compact formation on the pool table.
Pool games are extremely popular with people of all ages. Most games require that pool balls (often fifteen for playing "eight ball", but sometimes nine for the game of "nine ball") be arranged into a triangular or a diamond shaped pattern. The balls are arranged in a manner such that the apex of the formed diamond is located near a pre-marked spot on the pool table, which serves as a marker for placing the racked balls.
The pool balls must be arranged in a tight and compact formation to ensure that when it is first "broken", the balls do not deviate from their predictable lines of travel merely because of a poor racking of the pool balls. Unfortunately, there is no existing system that provides pool players with an easy mechanism for obtaining a tight formation of the desired shape on the pool table.
To rack the balls, most people use a triangular pool rack that holds the balls in its interior portion. The rack is removed once the balls are organized in a formation that roughly resembles the desired shape. Unfortunately, the size of the pool balls often lacks uniformity, which makes it difficult to properly rack the balls into a tight formation. As a result, the first player to break the rack of balls is at a disadvantage in that the improperly racked balls do not respond as would be anticipated from a properly racked set of pool balls.
Other devices have been proposed for the purpose of automatically racking pool balls or assisting therewith. Unfortunately, all of these devices operate by engaging the balls "en masse" in an attempt to press them together.
While these various devices attempt to provide simplified means for properly racking pool balls, none of these guarantee a tight and even formation. Additionally, these devices have a complicated structure and are expensive in construction, yet still fail to provide the desired results. Therefore, while these prior art units may be suitable for the particular purpose employed, or for general use, they would not be as suitable for the purposes of the present invention as disclosed hereinafter.


A valve assembly is adapted to be disposed in an automotive engine exhaust system at an outlet of an internal combustion engine. The assembly includes a valve body having an opening therethrough including an inlet portion and an outlet portion. A first valve and a second valve are disposed in the opening intermediate the inlet and outlet portions. The first and second valves have an open position and a closed position. The first valve blocks a first predetermined amount of the opening when in the closed position. The second valve blocks a second predetermined amount of the opening when in the closed position, with the second predetermined amount being less than the first predetermined amount. An actuator is connected to the first valve and the second valve and is operable to selectively move each of the valves between respective the open positions and the closed positions.

The present invention relates generally to automotive exhaust systems and, in particular, to a valve in an automotive exhaust system.
Automotive exhaust systems function to rout and treat an exhaust gas stream from an inlet connected to an internal combustion engine to an outlet to atmosphere. Exhaust systems include piping attached to the engine, and mufflers, catalytic converters, resonators and the like disposed in the piping to remove impurities and noises from the exhaust gas stream prior to the exhaust stream exiting to atmosphere. Exhaust systems function to maintain the flow of exhaust gases to atmosphere while also providing back pressure, i.e. restriction, for the engine.
With some newer engines able to switch between an eight cylinder mode and a four cylinder mode, this new powertrain option results in a high exhaust gas output mode and a low exhaust gas output mode. By varying the displacement of the engine, drastically different exhaust flow rates are produced, for example, when the engine is in eight cylinder or high output mode compared to when, for example, the engine is in a four cylinder or low output mode. Current commercially available valves in the exhaust system have dual inlet chambers containing flapper valves, which valves are passive devices that perform an open/closed operation to direct flow to a single outlet chamber. However, these passive devices are incapable of providing an adjustable restriction to exhaust gas flow due to changes in exhaust gas flow from a variable displacement engine.
It is desirable, therefore, to provide an exhaust valve assembly that is adapted to be disposed in an automotive exhaust system and is operable to maintain both flow and back pressure requirements for the exhaust system regardless of the type of engine and especially for an engine whose exhaust flows and back pressures can vary greatly due to engine cylinder deactivation.


According to one embodiment, an information processing apparatus includes a storage unit and a control unit. The storage unit stores in advance first identification information out of the first identification information and second identification information which are associated with the same user. The control unit acquires data of a job associated with the second identification information. The control unit suspends the execution of the job when the second identification information is not associated with the first identification information. The control unit authenticates the user using the first identification information. The control unit associates the second identification information with the first identification information when an operation determined in advance is received.

An image forming apparatus registered in a server providing a cloud service may be shared by a plurality of users. The image forming apparatus acquires data of a printing job from the server. The image forming apparatus executes the printing job. The image forming apparatus manages the number of printed copies for each user of the image forming apparatus. The image forming apparatus charges a user of the image forming apparatus in accordance with the number of printed copies. However, the image forming apparatus does not manage the association between identification information of a user of the server and identification information of a user of the image forming apparatus. For this reason, the image forming apparatus cannot charge the same user of the image forming apparatus in accordance with the number of printed copies of the user of the server even when the user of the server and the user of the image forming apparatus are identical.
The above-described problem that arises in association with a plurality of pieces of identification information is not limited to charging based on the number of printed copies and is a problem when only one of the different pieces of identification information associated with the same user is used by the information processing apparatus. In this manner, when first identification information out of the first identification information and second identification information which are associated with the same user is used by an information processing apparatus and the second identification information is not used by the same information processing apparatus, the first identification information and the second identification information cannot be associated with each other.

Information processing apparatus, information processing method and non-transitory recording medium


An electrophoresis microgel is formed in a gel holder. The gel holder comprises a top substrate, a bottom substrate and a spacer disposed between the top substrate and the bottom substrate. The spacer establishes a separation of from 25 to 250 microns between the top substrate and the bottom substrate. A gel compartment is formed by partially sealing the top substrate to the bottom substrate, while leaving an opening for the introduction of unpolymerized gel. The gel compartment is then filled with an unpolymerized gel, which is polymerized in the gel compartment. Electrodes may be printed on the substrates, may be contacts to an exposed edge of gel, or may be applied through windows cut into one of the substrates. One type of gel holder makes use of graded beads having a diameter of 25 to 250 microns slurried in an adhesive such as an acrylate adhesive as the spacer. The slurry is printed onto the surface of one or both substrates to form a spacer of the desired shape, and then hardened using heat or light. If desired, the spacer can establish lanes within the gel.

This application relates to microgels for use in medical diagnosis, especially for the sequencing of nucleic acids, and to methods of making and using such gels.
DNA sequencing may be carried out using automated systems designed for laboratory application. Methods and apparatus for sequencing of DNA are described in U.S. Pat. Nos. 4,811,218; 4,823,007; 5,062,942; 5,091,652; 5,119,316 and 5,122,345, which are incorporated herein by reference.
The general methodology employed in these systems involves breaking up the sample DNA using restriction endonucleases; amplifying (for example with PCR) the restriction fragment of interest; combining the amplified DNA with a sequencing primer which may be the same as or different from the amplification primers; extending the sequencing primer in the presence of normal nucleotide (A, C, G, and T) and a chain-terminating nucleotide, such as a dideoxynucleotide, which prevents further extension of the primer once incorporated; and analyzing the product for the length of the extended fragments obtained. Analysis of fragments may be done by electrophoresis, for example on a polyacrylamide gel.
International Patent Publication No. WO93/00986 describes electrophoresis gels with a thickness of 25 to 250 microns. The gels are formed between two clamped-together plates, one of which is grooved to a depth equal to the desired gel thickness to form parallel tracks which are then filled with gel.
In performing a nucleic acid sequence analysis on a gel, the characteristics of the gel, including the size and thickness, impact the time and cost required to do the analysis. Since it is desirable to reduce the time and cost of sequencing analyses in order to improve the available of sequencing as a diagnostic tool, it would be advantageous to have a gel which permitted analysis of very small quantities of oligonucleotide fragments in a short period of time. It is an object of the present invention to provide such a gel.
It is a further object of the invention to provide single-use, disposable gel holders which are readily filled with gel to provide a gel for rapid analysis of small samples.
It is a further object of the present invention to provide a method of making gels which achieve high resolution of oligonucleotide fragments in a short period of time.
It is a further object of the invention to provide a method of evaluating a sample containing oligonucleotide fragments of various lengths.

Microgels for use in medical diagnosis and methods of making and using same


The invention relates to the identification and selection of novel genomic regions (biomarker) and the identification and selection of novel genomic region combinations which are hypermethylated in subjects with prostate cancer compared to subjects without prostate cancer. Nucleic acids which selectively hybridize to the genomic regions and products thereof are also encompassed within the scope of the invention as are compositions and kits containing said nucleic acids and nucleic acids for use in diagnosing prostate cancer. Further encompassed by the invention is the use of nucleic acids which selectively hybridize to one of the genomic regions or products thereof to monitor disease regression in a patient and the efficacy of therapeutic regimens.

Reversible methylation of cytosines is a major epigenetic modification in multicellular organisms and is found in many human diseases including cancer. Cancer epigenomes are found to be globally hypomethylated with promoter-specific hypermethylations. Furthermore, cytosine methylation results in transcriptional repression, which, in the case of tumour suppressor genes, apoptotic genes, DNA repair genes and factors controlling cell cycle check points leads to tumour progression.
Prostate cancer (PC) is the third most common cause of male cancer deaths in developed countries. Diagnosed at an early stage PC is a curable disease. Therapies reach from watchful waiting to radical prostatectomy, hormone or radiation therapy. Nevertheless, because of its yet mostly unpredictable outcome patients are often treated without clear benefit.
Prostate specific antigen (PSA) is used as a biomarker to screen men for potential tumour development. However, low specificity and sensitivity leads to wrong diagnoses. In particular, elevated PSA can also result from an inflammation or precedent transrectal ultrasound, i.e. disclosure within the state of the art lacks an unequivocal diagnosis of PC.
It is therefore clear that there has been and remains today a long standing need for an accurate and reliable test to diagnose PC.
Recent years have brought a marked extension of our understanding of the somatic basis of prostate cancer. With one to three mutations per megabase the mutation frequency is similar to that observed in acute myeloid leukemia and breast cancer and lies within the lower range of cancer. Based on the frequency and the fact that primarily a diverse array of genes is affected the main genomic alterations appear to be genomic rearrangements and changes in the epigenetic structure of the DNA.
Michael Weber et al. (Nature Genetics, Vol. 37, No. 8, Aug. 1, 2005, pages 853-862) disclose DNA methylation markers for colorectal cancer. For the analyses colorectal cancer cell lines and tissues, and a prostate cancer cell line were used, but no primary prostate cancer tissues. In addition, experiments are based on arrays which narrow down the possibility to detect new DMRs.
Ilana Keshet et al (Nature Genetics, Vol. 38, No. 2, Feb. 1, 2006, pages 149-153) disclose methylation of GSTP1 and CDKN2A in Caco2 and PC3 cell lines (has been shown before) by PCR analyses. Furthermore, they compare methylation information obtained by MeDIP array (10.000 promoter elements) analyses of PC3, Caco2, normal lymphoblasts, normal colon tissue and six colon tumors. Again, no primary prostate cancer tissues have been used, and experiments are restricted to array regions.
Tokumaru (Clinical Cancer Research, Vol. 10, No. 16, Aug. 15, 2004, pages 5518-5522) disclose the usability of combinations of the methylation values of four genes obtained by qPCR to help in tumour classification of needle biopsies: Combinations of RARRES1, APC, RARB2, and GSTP1 methylation were used to classify 72 prostate samples (56 cancer, only 16 normal) with 100% specificity and 97% sensitivity. RARB2 as well as GSTP1 are listed in our patent application (SEQ ID NO: 36 and 108).
Hoque Mohammad Obaidul et al (Journal of clinical oncology, American Society of Clinical Onoclogy, Vol. 23, No. 27, Sep. 20, 2005, pages 6569-6575) disclose the usability of the methylation values of CDKN2A, p14ARF, MGMT, and GSTP1 as markers for qMSP based PCa detection in urinary sediment in 52 PCa cases and 91 age matched controls without precedent PCa history with a sensitivity of 87% and a specificity of 100%. Only GSTP1 may overlap with the regions listed below.
Jacinto Filipe V et al (Biotechniques, January 2008, Vol. 44, No. 1) review MeDIP experiments
Ke Xi-Song et al (BMC Genomics, Biomed Central, London, Vol. 11, No, 1, Nov. 25, 2010) performed array profiling (17.000 RefSeq genes −5.5 kb-+2.5 kb) of histone modifications (chromatin IP) and DNA methylation (MeDIP) in EP156T, EPT1 and EPT2 cells and correlated the results to gene expression profiles (Agilent 44 k chip) and disclose histone modifications with correlating gene expression changes during epithelial to mesenchymal transition (EMT). Here only cell lines are used, no DNA methylation PCa markers are named.
Matheys Lesley A et al (Molecular Cancer, Biomed Central, London, GB, Vol. 9, No. 1, October 2010) disclose hypomethylation in BMX and SOX1 in the invasive subpopulations of LNCaP and DU145 cells causing overexpression of said genes and name alterations in the STAT3 pathway as key features of invasiveness. Using MeDIP array analyses they found 869 genes hypermethylated in invasive LNCaP (1015 in invasive DU145) and 44 genes hypomethylated in invasive LNCaP and DU145 cells. They compared subpopulations of prostate cancer cell lines and did not include prostate tissue specimens to validate the significance of their findings in clinical samples.
U.S. Pat. No. 6,812,339 disclose single nucleotide polymorphisms (SNPs) in genes that have been identified as being involved in pathologies associated with human disease. The diseases/pathologies that each gene is known in the art to be associated with is specifically indicated in Table 1 therein. The US patent does not relate to methylation patterns at all and uses a different approach. A nucleic acid disclosed therein shares some similarity with SEQ ID NO. 1 herein.
Aberrant DNA methylation plays an important role in prostate cancer development and seems to be one of the earliest events in tumourigenesis. The most prominent differentially methylated gene in prostate cancer is glutathione S-transferase pi 1 (GSTP1).
Other genes with changes in promoter methylation include multidrug resistance protein 1 (MDR1), O-6-methylguanine-DNA methyltransferase (MGMT), Ras association domain family member 1 (RASSF1), retinoic acid receptor beta (RARB), adenomatous polyposis coli (APC), androgen receptor (AR), cyclin-dependent kinase inhibitor 2A (CDKN2A), E-cadherin (CDH1) and CD44, but show inconsistent methylation levels in different studies.
Even though the relevance of DNA methylations for normal cell homeostasis is undeniable, little is known about the genomic distribution in normal and diseased states. Accordingly, there is a need in the state of the art of studying genome-wide aberrant DNA methylation that can be associated with high confidence to PC and identifying biomarkers for PC diagnosis based on the epigenetic cancer information.

Max-Plank-Gesellschaft Zur Foerderung Der Wissenschaften E.V.


A process for making a water-insoluble, graft copolymer of lignite-(ethene or substituted ethene monomer) having a central lignite network and at least one grafted side chain, R, having "m" repeating units of (1-phenylethylene), 1-methyl-1-(1-oxo-2-oxypropyl)ethylene, a polymerized 2-methyl-3-oxo-4-oxybut-1-ene-(p-ethoxy-(3*p+3)-ol, or any other substituted ethene monomer which has a dipole moment of less than 1.2 or a water solubility of less than 5 g/100 g water at 30.degree. C. The ethene monomer forms the sidechain by free radical polymerization and, in the sidechain, m and p vary from 1 to 300,000 such that the central lignite network has a molecular weight of about 1,000 to 1,500,000; the total number of random units in a grafted side chain is in the range of 1 to 300,000 units; and the total number of sidechains attached to lignite, x, is in the range of 1 to 500; such that the total copolymer molecular weight is in the range of 1,500 to 30,000,000. This process makes a material which is a hard, strong, thermoplastic that can be molded, cast, and extruded into parts, equipment, and consumer items.

In 1988, the United States produced a larger volume of polymers and plastics than the entire annual production volume of steel, aluminum, and copper combined. Polymers have become the most common material in our daily lives and are critical items of commerce, industry, and technology. Aqueous solutions which flow at a controlled rate under a given shear stress are also required throughout a variety of industrial applications. Simultaneously, there is enormous need for materials that are ductile at room temperature and can be molded into articles of manufacture or complex shapes. This invention will disclose a unique class of materials that are useful in both applications.
The control of viscosity of water is achieved by adding to water agents such as clays, amounts of polar organic compounds such as polyacrylates, or high concentrations of salts. With the appropriate additives, these aqueous solutions can suspend large amounts of a solid phase and form a thermodynamically stable mixture. These aqueous solutions suspend finely divided solids and will flow slowly when exposed to shear stress. Such solutions, free of solids, also flow more uniformly in situations where numerous paths providing different resistances to flow are open to the fluids.
When a solid must be formed, the materials used to control fluid flow are, generally, not considered. This is because the fluid flow agents form brittle or hydroscopic solids that decompose instead of becoming extrudable when heated. Since materials that can be reformed into articles of manufacture just by heating and plastic processing are very desirable, a large class of compounds which exhibit this behavior have been invented.
However, each of the conventional agents for flow control or solid formation has attendant disadvantages. Hence, a need continues to exist for new agents which are capable of suitably thickening water and aqueous solutions or making objects of manufacture with functional strength and resistance properties. Further, most of the polymeric compounds used in flow control or article manufacture are made from expensive, petrochemical-derived, synthetic chemicals rather than cheaper natural compounds like lignite. Compounds which contain large amounts of lignite are desirable, cheap products because of low raw materials cost. Lignite-containing materials also have a two part structure with the lignite and synthetic parts of the compound tending to phase separate or seek different chemical environments. This difference in affinities produces surface activity which allows the production of very novel thickening agents or plastics. Thickening agents, flow control agents, and thermoplastic solids containing large amounts of lignite are desirable materials because of surface activity, chemical properties, and low materials cost.
Further, there are significant disadvantages in the production of two part molecules containing lignite, particular by chain reaction with a free radical active site. Such processes are disclosed in the patents by Huddleston, U.S. Pat. No. 5,028,271 and U.S. Pat. No. 4,938,803, and the patents of Fry, U.S. Pat. No. 4,703,801 and U.S. Pat. No. 4,676,317. These patents use a polymerization run in the presence of an additive to conduct a free radical reaction. A polymerization run in the presence of an additive is an alteration of an existing polymerization method for reacting a given monomer. An example of the existing polymerization method for the monomer is prepared and the reaction is contaminated with an additive which is supposed to become the backbone of a graft copolymer. The polymerization is run and the product is labeled a graft copolymer of the additive. The problems with this approach are several:
1. Contaminating a previously functional polymerization with an additive allows components of the additive or the additive itself to interfere with the polymerization. The result is a reduced or zero yield of polymer. PA1 2. The polymerization being contaminated with an additive was not designed to initiate polymerization upon and create copolymer with, the additive. If any grafting reactions occur with the additive, they occur in the termination reaction of the polymerization, leading to a. lower molecular weights in the product as the result of chain transfer or b. lower yield as a result of loss of an active polymerization site. PA1 3. Since the polymerization method was a known reaction, it initiates and propagates the polymerization of the monomer just as it was originally designed to do. Graft copolymer may be formed only in termination by combination of radicals or by chain transfer attack of the polymerizing chain onto the backbone. Since these two reactions must compete with the ordinary termination reactions of the polymerization method, they are infrequent and will yield little, if any copolymer. They do not allow quantitative grafting of all molecules of the additive. PA1 4. Any limitations of the method chosen as the basis for the polymerization in the presence of additive continue to be limitations of the method. PA1 1. The plant biomass compacts as time passes so that the tubules, capillaries, and cell structure that permeate early lignite decrease in diameter and length. With increasing age since deposition, these structures become smaller and the lignite changes from a porous media to a microporous solid to an impermeable solid with increasing age. PA1 2. The elemental composition of the lignite changes with time. Thus, if the elemental analysis of a gram of dry lignite were written C.sub.v H.sub.w O.sub.x N.sub.y S.sub.z, then when samples of the lignite were assayed after different amounts of time in the ground, the hydrogen to carbon ratio, w/v, would decrease. Further, the amount of oxygen in the sample, x, would decrease as the millions of years passed. Very crudely, the hydrogen-carbon ratio might change quickly from a modern value of almost 2 to somewhere around 1.2. It then would slowly change from 1.2 toward 0.8 and eventually toward 0.6. PA1 3. As the age of the lignite increases, the fraction of carbon in aromatic structures increases. PA1 4. Simultaneously, the number of aromatic rings fused together into small connected clusters increases from 1 ring toward 4 as the age of the lignite increases. The ring clusters are interconnected by cycloalkyl structures that themselves form 6 member rings. PA1 5. The oxygen in the molecules is in the form of hydroxyl and quinone groups.
It is impossible by previous methods to graft lignite if similarly substituted ethenes with a different dipole moment and sharply reduced water solubility are used in place of ionic, acid, amine, or amide monomers in previously disclosed synthesis methods. With ethene monomers with dipole moments below 1.2 or water solubilities of less than 5.0 g of monomer per 100 g of water at 30.degree. C., reactions run according to previously disclosed procedures give zero yield of graft copolymer.
Lignites are a class of materials often used as fuel. The materials are "short" internment, fossil fuels that would eventually; under the actions of time, pressure, microorganisms, water, and geologic process; become hard coals, bituminous or anthracite. Lignites, also called brown coal, thus range from peats, starting with "mature peats" or "immature brown coals", to bituminous coal. The American Society for Testing and Materials has classified coals by heat content with lignites having a moist-basis, heat value below 19.29 MJoules/Kg. This classification is not absolute, however, and other classification procedures, such as those of the International Classification of Hard Coal by Type or the International Classification for Brown Coals for the Peoples Democracies, differ from this specification.
Peat generally has large pores with less than 50 percent carbon in vitrinite, details of initial plant material still recognizable, and free cellulose present in the material. Soft brown lignite generally has reduced pores with more than 50 percent carbon in vitrinite, details of initial plant material still recognizable, and little or no cellulose present in the material. There is often from 35 to 75 weight percent water in the material as mined. At the transition between soft brown lignite and dull brown lignite, the cell cavities are frequently empty.
Dull brown lignite generally has minimal pores, details of initial plant material still recognizable, and no free cellulose present in the material. There is often from 25 to 35 weight percent water in the material as mined. The percent reflectance of vitrinite is often 0.3 or above and the percent carbon in vitrinite is 65 percent or more. The volatile matter in dry, ash-free vitrinite is usually between 49 and 53 weight percent and the heat content is between 16.7 and 23.0 MJoules/Kg. As soft brown lignite becomes dull brown lignite or brown coal, marked gelification and compaction takes place.
Bright brown lignite generally has cell cavities filled with collinite, details of initial plant material still partially recognizable, and no free cellulose present in the material. There is often from 10 to 25 weight percent water in the material as mined. The percent reflectance of vitrinite is often 0.4 or above and the percent carbon in vitrinite is 70 percent or more. The volatile matter in dry, ash-free vitrinite is usually between 45 and 49 weight percent and the heat content is between 23.0 and 29.3 MJoules/Kg. The properties listed change gradually as the bright brown lignite/coal becomes bituminous hard coal.
The above descriptions are based on the use of lignite as a fuel. Chemically, lignite is a naturally occurring, organogel deposit formed in the anaerobic decomposition of plants under acidic conditions. The simplest difference between the plant and lignite is one million years of weathering, compaction, and rotting., Table, 1 lists some lignite deposits by location and the time since the deposit was layed down. Further data on lignite can be found in "Low-Rank Coal Technology: Lignite and Subbituminous" by G. H. Gronhovd, Noyes Data Corp., Park Ridge, N.J., (1982).
TABLE 1 ______________________________________ Location and Age of Some Lignite Deposits. Location Millions of Years Geologic Period in of the Since Deposition Which Deposition Deposit. Occurred. Occurred. ______________________________________ New Zealand One Pleistocene Tasmania One Pleistocene Alaska Two Pliocene Southeastern Europe Two Pliocene Central Germany Twenty Miocene England Fourty Oligocene ______________________________________
In the time listed in Table 1 between when the plant died and when humans discovered the deposit of plant atoms, major changes take place in how those atoms are bound together. A list of these changes is given below.
A structure which contains some of the appropriate functional groups is shown as structure 1. It may be representative of some parts, interconnections, or sections of molecules in lignite. ##STR1##
Structure 1 is only a display of the type of structure for which chemists have seen spectral and chemical, identifiers. It should not be taken as the actual structure of the molecules that make up lignite. As noted above, however, it should reflect the structures that are found in parts of lignite. Further data on the structure and composition of lignite can be found in "Chemistry of Lignite Liquefaction", prepared for the U.S. Energy Research and Development Administration by the University of North Dakota under contract #E(49-18)-2211, National Technical Information Service, (1976).
No broadly functional methods to graft lignite are known. A method has now been developed which allows ethene monomers to be attached to lignite and lignite polymers and thermoplastics to be made. This invention provides a broad spectrum of soluble or extrudable copolymers and methods for making said copolymers.
The objectives of the present invention include: 1. provide new copolymers containing lignite as the backbone component with a side chain or chains formed from a vinyl monomer; and 2. methods for synthesizing lignite copolymers having vinyl monomer side chain or chains.
Accordingly, it is an object of the present invention to provide a series of methods for synthesizing a lignite graft copolymer. It is also an object of the present invention to provide a spectrum of reagents to use in the processes for preparing the lignite graft copolymer. Further, it is also an object of the present invention to provide a method of boosting or enhancing polymer molecular weights during polymerization reactions. Typical monomers that can be used to add a side chain to lignite are those with the general structure: ##STR2## where R.sub.1, R.sub.2, R.sub.3, and R.sub.4 are organic or inorganic functional groups which do not interfere with free radical polymerization. Alternatively, the reaction can be run with the above monomers and some amount of a diethene compound, ##STR3## where R.sub.5, R.sub.6, and R.sub.7 are organic or inorganic functional groups which do not interfere with free radical polymerization. The diethene compound will cause crosslinking of grafted molecules during the polymerization and, at low concentrations, will produce a higher molecular weight copolymer. At high concentration of diethene compound, a crosslinked solid will be produced by the reaction. These monomers are reacted with lignite to create a two part molecule such that the central lignite network has a molecular weight of about 1,000 to 1,500,000; the total number of random units in a grafted side chain is in the range of 1 to 300,000 units; and the total number of sidechains attached to lignite, x, is in the range of 1 to 500; such that the total copolymer molecular weight is in the range of 1,500 to 30,000,000.

Process for making graft copolymers from lignite and vinyl monomers


A carrier travel layer is formed on the substrate of a semiconductor device with a buffer layer interposed, and a spacer layer and carrier supply layer are then formed on this carrier travel layer. On the carrier supply layer are provided a source electrode and a drain electrode, and a gate electrode is provided on an interposed Schottky layer. The carrier supply layer is composed of AlGaN and has tensile strain. The Schottky layer is composed of InGaN and has compressive strain. A negative piezoelectric charge is induced on the carrier supply layer side of the Schottky layer, and a positive piezoelectric charge is induced on the opposite side of the Schottky layer, whereby a sufficient Schottky barrier height is obtained and leakage current is suppressed.

1. Field of the Invention
The present invention relates to semiconductor device that is provided with a Schottky electrode, and more particularly to a field-effect transistor having high breakdown resistance for application in high-frequency and high-temperature operation.
2. Description of the Related Art
As disclosed by, for example, Lei Wang et al. (Applied Physics Letters Vol.68 (No.9) pp.1267 (1996)), it is known that GaN semiconductors have a higher Schottky barrier than other Group III-V compound semiconductors.
According to the publication mentioned above, Wang et al. fabricated Pt/GaN and Pd/GaN Schottky diodes and measured the Schottky barrier heights of each. The Schottky barrier height of a Pt/GaN Schottky diode was 1.13-1.27 eV, and the Schottky barrier height of a Pd/GaN Schottky diode was 0.96-1.24 eV. These values are higher than the GaAs Schottky barrier height (0.7 eV or lower) or the InP Schottky barrier height (0.5 eV or lower).
In a heterojunction field-effect transistor (HJFET), an AlGaN layer is normally used as the semiconductor layer (electron barrier layer) that contacts a Schottky electrode. This is disclosed by, for example, Egawa et al. (Applied Physics Letters Vol.76 (No.1) pp.121 (2000)).
FIG. 1 is a sectional view of a field-effect transistor disclosed by Egawa, et al. As shown in FIG. 1, GaN seed formation layer 1002 having a film thickness of 30 nm, GaN layer 1003 having a film thickness of 2.5 xcexcm, AlGaN spacer layer 1004 having a film thickness of 10 nm, n-type AlGaN carrier supply layer 1005 having a film thickness of 20 nm, and n-type GaN cap layer 1006 having a film thickness of 20 nm are formed by metalorganic vapor phase epitaxy method on sapphire substrate 1001. A portion of GaN cap layer 1006 and AlGaN carrier supply layer 1005 is then removed by a reactive ion etching (RIE) method. Source electrode 1007 and drain electrode 1008 are then formed from Ti/Al, and gate electrode 1009 is formed from Pt/Ti/Au, thereby completing the field-effect transistor. Because the AlGaN layer has a larger band gap than a GaN layer, the Schottky barrier height at the interface of the Pt and AlGaN is higher than the Schottky barrier height at the interface of the Pt and GaN.
Nevertheless, Schottky barrier height is insufficient in the configuration of the prior-art during operation in which a Schottky voltage is applied in the positive direction. In particular, in the case of a field-effect transistor in which current across the source and drain is 0 when gate voltage is not applied, i.e., a field-effect transistor that operates in enhancement mode, there is the problem that the leakage current increases and the amplification factor deteriorates during operation, i.e., when a Schottky voltage is applied in the positive direction.
As a countermeasure, a method can be considered in which the thickness of the AlGaN layer is increased to raise the Schottky barrier thickness and decrease the leakage current. However, limitations exist in relation to the critical layer thickness, and increasing the thickness of the AlGaN layer sufficiently to obtain adequate Schottky barrier thickness is problematic. Increasing the Al composition in the AlGaN layer to raise the Schottky barrier height can also be considered. However, increasing the Al composition component brings about an increase in tensile strain within the layer and a decrease in the critical layer thickness, and obtaining sufficient Schottky barrier height is again problematic.
In view of the above-described problems, it is an object of the present invention to realize a Schottky barrier having sufficient height, which could not be obtained in the prior art, and thus effectively suppress leakage current.
To solve the above-described problems, the present invention prevents leakage current by forming an energy band structure having a Schottky barrier of two-step construction and having sufficient height by providing a layer having a compressive strain below a Schottky electrode, as shown, for example, in FIGS. 2A and 2B.
In a case in which III-V semiconductor layers having different lattice constants are formed, internal strain occurs in the semiconductor layers, and it is known that the piezoelectric effect that is brought about by this internal strain generates an internal field in the layers. For example, in a case in which, on the (0001) plane of a thick base layer that is composed of a III-nitride semiconductor, a material is formed that has a larger lattice constant than the thick base layer, compressive strain will remain in the layer if the film thickness of the formed material falls below the critical layer thickness at which dislocation generates due to lattice mismatch. The piezoelectric effect brought about by this compressive strain generates an internal field in the direction from the interior of the layer toward the surface. If the formed material has a smaller lattice constant than the thick base layer, on the other hand, tensile strain will remain in the layer and an internal field will be generated in the opposite direction. The present invention takes advantage of this piezoelectric effect to increase the Schottky barrier height. In this specification, the (0001) plane in the III-nitride semiconductor crystal refers to the plane that is shaded with diagonal lines in FIG. 3.
A semiconductor device of this invention comprises: a first electron barrier layer, a second electron barrier layer that is formed on this first electron barrier layer either directly or on an interposed spacer layer, and a Schottky electrode that is formed on this second electron barrier layer. A negative piezoelectric charge is induced on the first electron barrier layer side of the second electron barrier layer, and positive piezoelectric charge is induced on the Schottky electrode side of the second electron barrier layer.
According to this semiconductor device, the effect of the piezoelectric charge that is induced in the second electron barrier layer can effectively increase the Schottky barrier height of the first electron barrier layer, thereby enabling an effective suppression of leakage current.
In this semiconductor device, moreover, adopting a construction in which a negative piezoelectric charge is induced on the second electron barrier layer side of the first electron barrier layer and a positive piezoelectric charge is induced on the opposite side of the first electron barrier layer further increases the Schottky barrier height that is brought about by the piezoelectric charges that are induced in the second electron barrier layer.
If the first and second electron barrier layers are both formed from III-nitride semiconductor materials, good piezoelectric polarization can be produced and the Schottky barrier height is further increased by the piezoelectric charges that are induced in the second electron barrier layer.
Another example of the semiconductor device of this present invention comprises: a base layer, a first electron barrier layer that is formed directly on the base layer, a second electron barrier layer that is formed either directly on this first electron barrier layer or on an interposed spacer layer, and a Schottky electrode that is formed on this second electron barrier layer. The base layer, the first electron barrier layer, and the second electron barrier layer are all wurtzite III-nitride semiconductors that take the (0001) plane as the principal plane. In addition, the second electron barrier layer has compressive strain.
In this semiconductor device, the second electron barrier layer has compressive strain, and a piezoelectric charge can therefore be induced in the second electron barrier layer and the Schottky barrier height in the first electron barrier layer can be effectively raised, thereby effectively suppressing leakage current.
In this semiconductor device, moreover, if a structure is adopted in which the first electron barrier layer has tensile strain, the piezoelectric charge that is induced in the second electron barrier layer further increases the Schottky barrier height.
If the average of the lattice constant in the horizontal plane that is perpendicular to the direction of thickness is defined as the average lattice constant, making the average lattice constant of the second electron barrier layer greater than that of the base layer can produce compressive strain in the second electron barrier layer and thereby obtain a semiconductor device of the above-described structure. The average lattice constant is not the lattice constant for a multilayer film, but rather, the lattice constant that is specific to the material that constitutes the layer. For example, in a case in which an AlGaN layer having an a-axis lattice constant that is smaller than that of GaN is grown above a thick base layer that is composed of GaN in which the (0001) plane is the principal plane, tensile strain occurs in the AlGaN layer, and the lattice spacing of the GaN layer and AlGaN layer is equal in the horizontal plane that is perpendicular to the direction of layer thickness. Average lattice constant in this invention does not relate to lattice spacing when this type of strain is in effect, but rather, to such lattice constant that is inherent to the material. The lattice constant in the horizontal plane that is perpendicular to the direction of layer thickness coincides with the a-axis lattice constant if there is no inclination to the (0001) plane.
In this semiconductor device, making the average lattice constant of the first electron barrier layer smaller than that of the base layer increases the Schottky barrier height due to the piezoelectric charge that is induced in the second electron barrier layer.
A construction is preferably adopted in which the base layer is made up by Alxcex1Ga(1xe2x88x92xcex1)N; (0xe2x89xa6xcex1xe2x89xa61), the first electron barrier layer is composed of Alxcex2Ga(1xe2x88x92xcex2)N; (xcex1xe2x89xa6xcex2xe2x89xa61), and the second electron barrier layer is composed of InxGayAl(1xe2x88x92xxe2x88x92y)N; (0 less than xxe2x89xa61, 0xe2x89xa6y less than 1).
In addition, a construction is preferably adopted in which the base layer is composed of Alxcex1Ga(1xe2x88x92xcex1)N; (0 less than xcex1xe2x89xa61), the first electron barrier layer is composed of Alxcex2Ga(1xe2x88x92xcex2)N; (xcex1xe2x89xa6xcex2xe2x89xa61), and the second electron barrier layer is composed of Alxcex3Ga(1xe2x88x92xcex3)N; (0xe2x89xa6xcex3 less than xcex1).
In this way, the Schottky barrier height can be sufficiently increased and leakage current can be effectively suppressed.
The present invention is particularly effective when applied to a field-effect transistor, such as a High Electron Mobility Transistor (HEMT) or Metal Semiconductor Field-Effect Transistor (MESFET). In other words, if a construction is adopted in semiconductor devices of each of the above-described configurations in which the Schottky electrode is gate electrode and source and drain electrodes are further provided, the effect of the present invention is more pronounced, gate leakage current is further decreased, and field-effect transistors of superior reliability can be obtained.
In this case, the source electrode and drain electrode are preferably formed in contact with a III-nitride semiconductor layer having tensile strain or having no strain. Adopting this configuration simultaneously raises the Schottky barrier height in the gate electrode and enables a reduction in the contact resistance of the source electrode and drain electrode.
Another example of a semiconductor device of the present invention comprises a plurality of wurtzite III-nitride semiconductor layers of that take the (0001) plane as the principal plane, and a gate electrode, source electrode, and drain electrode that are formed over the semiconductor layers, The plurality of III-nitride semiconductor layers include a first layer composed of GaN and a second layer composed of AlxGa(1xe2x88x92x)N; (0 less than xxe2x89xa61). The gate electrode is formed so as to contact the first layer, and the source and drain electrodes are formed so as to contact the second layer.
In field-effect transistors of the prior art, gate electrodes are normally provided on AlGaN to increase the Schottky barrier height, and the source and drain electrodes are provided on doped GaN to reduce contact resistance. In the present invention, in contrast, the gate electrode is provided on GaN to increase the Schottky barrier height, and the source and drain electrodes are provided on AlGaN to increase the ohmic property of the electrodes. The Schottky barrier height of the gate electrodes can be increased because the surface of wurtzite GaN in which the (0001) plane is the principal plane has negative polarity. The Schottky barrier height can be increased because the GaN layer has a negative polarity in the vicinity of the interface on the gate electrode side. The effect of the negative polarity of the GaN surface and the effect of the above-described second electron barrier layer are each produced by different mechanisms, but the latter effect can obtain a more marked increase in the Schottky barrier height. A more effective configuration can be obtained if the GaN layer is caused to have compressive strain by adopting a method such as using AlGaN for the base layer.
The effects of the present invention are next described with reference to the accompanying drawings.
Wurtzite III-nitride semiconductors exhibit a piezoelectric effect in which potential is generated by the strain of crystals. For example, if AlGaN layer 1102 having a smaller lattice constant than a GaN layer is formed on GaN layer 1101 in which the (0001) plane is the principal plane, a positive charge is produced in the AlGaN on the side of heterojunction with GaN (on the side of the (000-1) plane of the AlGaN layer) and a negative charge is produced on the opposite side (on the (0001) plane side of the AlGaN layer), as shown in FIG. 4A. Conversely, if InGaN layer 1104 having a greater lattice constant than a GaN layer is formed on GaN layer 1103 in which the (0001) plane is the principal plane, a negative charge is produced in the InGaN layer on the side of the heterojunction with the GaN (the (000-1) plane side of the InGaN layer) and a positive charge is produced on the opposite side (the (0001) plane side of the InGaN layer), as shown in FIG. 4B.
In a Schottky electrode construction of the prior art, the Schottky barrier height is secured by adopting the above-described energy band structure of FIG. 4A. For example, in the HJFET (Heterojunction Field-Effect Transistor) shown in FIG. 1, AlGaN spacer layer 1004 and AlGaN carrier supply layer 1005 are provided on GaN layer 1003, and gate electrode 1009 is further formed over these layers to form an energy band structure as shown schematically in FIG. 4A.
In this configuration, however, there is a limit to the extent that the Schottky barrier height can be further increased. Although the Schottky barrier height can be increased if the AlGaN layer immediately underlying the gate electrode is made thick, there is a limit to the film thickness in relation to the critical layer thickness as described in the foregoing explanation, and there is constantly a limit to increasing the Schottky barrier height.
In the present invention, in contrast, an improvement in barrier height by means of the piezoelectric effect can be contrived by providing a semiconductor layer that has compressive strain directly beneath the electrode. This point is next explained with reference to FIGS. 5A-5D.
FIG. 5C shows an HJFET of the prior art, and FIG. 5A shows the corresponding band chart. Thick GaN base layer 92 is formed on substrate 90 with buffer layer 91 interposed, and AlGaN layer 93 and electrode 95 are formed on this GaN base layer 92. The crystal growth plane of each of the III-nitride semiconductor layers is the (0001) plane.
The HJFET construction according to the present invention, on the other hand, is shown in FIG. 5D, and the corresponding band chart is shown in 5B. This construction differs from the construction shown in FIGS. 5A and 5C in that InGaN layer 94 (the second electron barrier layer) is provided between AlGaN layer 93 (the first electron barrier layer) and electrode 95.
The Schottky barrier height can be effectively increased in the HJFET of the present invention because this InGaN layer 94 has compressive strain in the horizontal plane that is perpendicular to the direction of thickness. In this HJFET, the relationship of size of the crystal lattice constants of the semiconductor layer and thick GaN base layer 92 determines whether the internal strain of each semiconductor layer is compressive or tensile. Compressive strain in the surface occurs because the lattice constant (the a-axis lattice constant) in the horizontal plane that is perpendicular to the direction of thickness of InGaN layer 94 is greater than that of GaN base layer 92. As a result, a piezoelectric effect operates such that a positive charge is produced on the (0001) plane side and a negative charge is produced on the (000-1) plane side. The barrier height between a Schottky metal and III-nitride semiconductor is determined by the substances, and the conduction band energy of a III-nitride semiconductor that takes the Fermi level of the metal as a reference increases with distance from the interface of the metal and semiconductor. In other words, the barrier height for electrons increases with increasing distance from the interface between the metal and semiconductor. Thus, the leakage current at a Schottky interface can be reduced compared to the prior-art example (FIG. 5A), and a superior current amplification characteristic can be realized even when the gate bias is positively applied.
The above-described points are next explained in greater detail. The Schottky barrier height xcfx86B1 in the energy band structure of FIG. 5B is represented by the following equation:
xcfx86B1=(xcfx86InGaN+xcex94Ec+Vpiezo
xcfx86InGaN is the Schottky barrier height of InGaN.
xcex94Ec is the value of ((the energy of the lower end of the conduction band of AlGaN)xe2x80x94(the energy of the lower end of the conduction band of InGaN)).
Vpiezo is the potential difference caused by polarization occurring in InGaN layer 93 due to the piezoelectric effect.
In contrast, the Schottky barrier height xcfx86B2 in the energy band structure of FIG. 5A is represented by the following equation:
xcfx86B2=xcfx86AlGaN
xcfx86AlGaN is the height of the Schottky barrier of AlGaN.
The amount of increase of the Schottky barrier height due to the present invention can be found from xcfx86B1xe2x88x92xcfx86B2. Since (xcfx86InGaN+xcex94Ec) and xcfx86AlGaN are substantially equal, this amount of increase is substantially equal to Vpiezo. In other words, the present invention increases the Schottky barrier height by taking advantage of the piezoelectric polarization that is generated in a layer having compressive strain that is arranged directly beneath an electrode.
The first electron barrier layer of the present invention is provided for increasing the electron barrier of the second electron barrier layer. The second electron barrier layer is preferably formed over and in direct contact with the first electron barrier layer, but may also be formed on an interposed spacer layer having a thickness of, for example, 10 nm or less.
The base layer of the present invention is the thickest layer of the semiconductor layers that make up the semiconductor device, and is the layer that restricts the crystal systems of the other semiconductor layers. The strain modes of the other semiconductor layers are determined with this base layer as the standard. In other words, tensile strain is produced in layers having a lattice constant that is smaller than that of the base layer, and compressive strain is produced in layers having a lattice constant that is greater than that of the base layer.
When a semiconductor layer having a lattice constant that differs from that of the base layer is formed over the base layer, dislocation is generated and lattice relaxation occurs in the semiconductor layer if the semiconductor layer is thicker than a critical layer thickness. Thus, in order to generate sufficient piezoelectric polarization and make the effect of the present invention significant, the thickness of the semiconductor layer is preferably kept at or below the critical layer thickness. Nevertheless, lattice relaxation normally does not proceed to completion, and a fixed lattice strain remains even when the semiconductor layer is thicker than the critical layer thickness. As a result, a film thickness that exceeds the critical layer thickness can be adopted in the present invention if within the range in which a fixed piezoelectric effect can be obtained.
Although the first and second electron barrier layers are preferably less than the critical layer thickness as described hereinabove, there is no particular lower limit, and, for example, these layers may have a thickness that is only several times greater than the size of the atoms (on the order of 10 xc3x85).
The critical layer thickness can be calculated using Matthews"" Equation (J. W. Matthews and A. E. Blakeslee; Journal of Crystal Growth, 27 118 (1974)). FIGS. 6 and 7 show the calculation results. The parameters used in this calculation are shown in the following table.
As described in the foregoing explanation, the provision of a layer having compressive strain below the Schottky electrode both enables the formation of a Schottky barrier of two-step structure having sufficient height and enables the effective prevention of leakage current below the electrode.
The above and other objects, features, and advantages of the present invention will become apparent from the following description with reference to the accompanying drawings which illustrate examples of the present invention.

Semiconductor device with schottky electrode having high schottky barrier


The subject invention pertains to materials and methods for inhibiting bacterial growth. Specifically provided are compounds which control bacteria by interfering with cell wall synthesis.

Despite the existence of many useful antibiotics, bacterial infections remain a major problem affecting human and animal health, agriculture, and industrial processes. The continued emergence of resistant bacteria heightens the need for the identification of new and effective antibacterial agents. The most advantageous of the antibacterial agents are those which can be used to selectively control bacteria without posing any health hazards for humans or animals. The identification of such agents is fraught with difficulties and uncertainties due in part to the many biochemical similarities between all living organisms. The identification of antibacterial agents remains an empirical process requiring extensive effort and the investment of substantial resources.
Bacteria in general synthesize a variety of extracellular glycans which provide structural integrity and a protective "wall" to the cell. Inhibition of the biosynthesis of this "wall" has been a favored approach in the design of drugs for the treatment of infectious disease because animal cells do not synthesize these walls. Most of the widely used and clinically effective antibiotics, such as the penicillins (cephalosporins) and vancomycin, function because they inhibit bacterial cell wall biosynthesis. The metabolic targets of each of these drugs are enzymes involved in the polymerization of the glycan chain and the cross-linking of the glycan chains. The biochemical pathway involved in cell wall synthesis is shown in FIG. 1.
One component of importance in cell wall biosynthesis is a C.sub.55 isoprenoid lipid called undecaprenyl phosphate (C.sub.55 --P). This lipid acts as a catalyst in gathering and transferring carbohydrate residues to the growing cell wall. The synthesis of a repeating saccharide unit of peptidoglycan occurs on the C.sub.55 isoprenoid lipid at the cytoplasmic face to the inner plasma membrane. This saccharide unit, while linked to the lipid, is translocated to the paraplasmic surface of the membrane where these sugars are transferred to the growing peptidoglycan.
The translocation of the C.sub.55 isoprenoid lipid back to the cytosolic compartment may be an energy dependant process. In an alternate pathway, the C.sub.55 isoprenoid lipid is hydrolyzed to free undecaprenol (C.sub.55 OH), which is translocated in an energy independent or low energy process to the cytosolic side of the membrane. At the cytosolic membrane surface, undecaprenol is then phosphorylated by a ATP-dependant undecaprenol kinase to regenerate the lipid, undecaprenyl phosphate, necessary for the next saccharide translocation process. The undecaprenol kinase enzyme is encoded by the gene known as bac-A which has been described by Cain et al. [Cain, Brian D., Peter J. Norton, Willis Eubanks, Harry S. Nick, Charles M. Allen (1993) "Amplification of the bacA Gene Confers Bacitracin Resistance to Escherichia coli" J.Bacteriology 175(12):3784-3789].
Although de novo biosynthesis provides the bulk of the initial pool of undecaprenyl phosphate, two alternative mechanisms are involved in maintaining an adequate pool size of C55--P for cell growth: 1) regeneration of undecaprenyl phosphate from the hydrolysis of undecaprenyl phosphate following saccharide transfer to the growing glycan; and 2) phosphorylation of free undecaprenol. The phosphorylation of free undecaprenol has previously been described as a "salvage" pathway. Although the enzyme responsible for the phosphorylation of free undecaprenol was crystallized over 20 years ago, there is no information published about its mechanism of action and little is known about its metabolic function.

Materials and methods for inhibiting bacterial cell wall biosynthesis


The present invention relates to a clip type light emitter, and in particular to a clip type light emitter capable of enhancing a visual field at night by detachably engaging a clip type light emitter to a leisure cap (including hat) generally used for a mountain climbing or fishing or travel or various sports. The clip type light emitter comprises a casing forming a body; a plurality of lamps provided at a front side of the casing at regular intervals; a switch part provided in one side of the casing; a battery provided in the interior of the casing; and a clip provided in an upper side of the casing and having one side end integrally engaged with the casing and having a certain elastic force, wherein the clip type light emitter is detachably engaged to a leisure cap (including hat) used for a mounting climbing, a fishing or various outdoor leisure and sports.

1. Field of the Invention
The present invention relates to a clip type light emitter, and in particular to a clip type light emitter capable of enhancing a visual field at night by detachably engaging a clip type light emitter to a leisure cap (including hat) generally used for a mountain climbing or fishing or travel or various sports.
2. Description of the Background Art
Generally, people use a cap for protecting a face during a mountain climbing or fishing or preventing sweat falling down on the face.
In addition, a cap is commonly used during a travel or various sports for same purpose. Recently, the cap is used as a part of a fashion.
The cap is provided for various different purposes such as a fashion cap enhancing a fashion feeling, a winter cap for a cold weather, a safety cap for a safety of a worker, a cap for various sports, a leisure cap, etc.
Among the above various caps, in the case of the safety cap used for a safety when a worker works in a dark place such as a tunnel, a mine, etc., a certain lamp is installed at a front side of the cap for enhancing a visual field.
However, as shown in FIG. 1, there is not provided a certain light emitter device in the case of a leisure cap or a sports cap for a mountain climbing, a fishing, etc. except for the above safety cap. Therefore, there is additionally provided a certain lamp or flash for the people who enjoy a night climbing, a night fishing, etc. or the people who enjoys various sports at night in a place in which there are not provided any lighting devices.
In addition, when people walk in a side street in which there is not provided any streetlight, since a visual field is not fully provided, various accidents happen.

This patent is subject to a terminal disclaimer.


Apparati, methods, and computer readable media for authenticating an entity (9) in a shared hosting computer network (4) environment. A service provider computer (2) contains a plurality of entity sites (5). Connected to the service provider computer (2), a trusted third party computer (1) is adapted to provide a conglomerated authenticity certification to the service provider computer (2). Coupled to the trusted third party computer (1) is a means (10) for enabling an entity (9) to seek to convert the conglomerated authenticity certification into an individualized authenticity certification covering that entity's site (5).

In a computer network such as the Internet, it is common for a plurality of entities to be hosted on a single server computer. For example, several entities may wish to have their Websites hosted on a single computer to save costs associated with purchasing and maintaining a server computer. This is called a shared hosting environment. It is common for these entities to wish to have their Websites authenticated by a trusted third party. An example of such a trusted third party is a certification authority such as VeriSign, Inc. of Mountain View, Calif. The authentication establishes that the entity is legitimate and gives assurance to others, such as potential customers of the entity, that they may safely conduct business with the entity. The authentication may take the form of a digital certificate using public key cryptography. Authentication and encryption can be combined in a protocol such as SSL (Secure Sockets Layer). Alternatively, non-cryptographic authentication may be used, such as a seal or a plug-in software module containing evidence of authentication by the trusted third party.
In a shared hosting environment, the trusted third party typically issues a digital certificate to the owner or operator of the server computer, e.g., an Internet service provider (ISP), but does not issue individual digital certificates to the entities, due to limitations in the HTTP (hypertext transfer protocol) and SSL protocols. Therefore, Internet service providers using SSL in a shared hosting environment typically use a shared SSL digital certificate that has been authenticated and issued to the Internet service provider but not to the individual entities. This is referred to as "shared SSL" and is popular in lower-end Websites and entry-level hosting plans. In shared SSL, the Website automatically redirects from the entity's site (e.g., http://www.entity.com) to a secure page hosted by the Internet service provider (e.g., https://secured.isp.com or https://*.isp.com, where the wildcard character * can represent any hostname, such as the name of the entity). In HTTPS, the "S" stands for "secure." If a customer of the entity attempts to obtain more information about the entity by means of clicking on the security padlock icon displayed by his or her browser, the customer will obtain information about the Internet service provider, since the ISP is the certificate holder. The customer will not be able to have the assurance that a trusted third party has performed due diligence on the entity itself.
In shared SSL, the ISP may be tempted to allow the entities hosted by the ISP to use the ISP's certificate as issued by the trusted third party. This may constitute a violation of the agreement between the ISP and the trusted third party, especially when the ISP charges for such a service.
The present invention provides a means for a trusted third party to provide authentication of individual entities in a shared hosting environment, without needing to change the HTTP and SSL protocols.

Entity authentication in a shared hosting computer network environment