The present invention relates to a plasma display apparatus and driving method thereof, wherein rising and/or falling times of data pulses applied to address electrodes in an address period are controlled to reduce noise generation. Thus, address discharge is stabilized, discharge efficiency of plasma display panel is enhanced, and electrical damage to data drive ICs is prevented. The plasma display apparatus includes a plasma display panel including a plurality of address electrodes, a data driving unit including a plurality of data drive ICs that has a plurality of channels, wherein the data drive ICs are electrically connected to the address electrodes through the channels and drive the address electrodes, and a data pulse controller that controls the voltage-rising time and/or the voltage-falling time of the data pulses applied to the plurality of the address electrodes in an address period to be a sufficient duration, e.g. 100 ns or longer, by controlling the data driving unit.

1. Field of the Invention
The present invention relates to a plasma display panel, and more particularly, to a plasma display apparatus and driving method thereof, which can control rising and falling times (durations) of data pulses applied to address electrodes in an address period, thereby reducing noise generation, stabilizing address discharges, and preventing electrical damage to driving circuits.
2. Background of the Related Art
Generally, a plasma display panel includes barrier ribs formed between a front substrate and a rear substrate. Together, the barrier ribs and the front and rear substrates form cells. Each of the cells is filled with a primary discharge gas such as neon (Ne), helium (He) or a mixed gas comprising Ne and He. In addition, each cell contains an inert gas comprising a small amount of xenon. If the inert gas is discharged using a high voltage, vacuum ultraviolet rays are generated. The ultraviolet rays excite light-emitting phosphors formed between the barrier ribs to display an image. Plasma display panels can be made thin and slim, and have thus been in the spotlight as one of the next-generation of display devices.
FIG. 1 is a perspective view illustrating the construction of a related art plasma display panel. In FIG. 1, the related art plasma display panel includes a front substrate 100 in which a plurality of pairs of display electrodes, which are formed by a plurality of pairs of scan electrodes 102 and sustain electrodes 103, are arranged on a front glass 101 that serves as a display surface on which the images are displayed. The plasma display panel also includes a rear substrate 110, in which a plurality of address electrodes 113 cross the plurality of display electrodes, is arranged on a rear glass 111 forming a rear surface. The front substrate 100 and the rear substrate 110 are parallel to each other with a predetermined distance therebetween.
The front substrate 100 includes the pairs of the scan electrodes 102 and the sustain electrodes 103 to perform discharge against the other mutually and maintain emission in one discharge cell. The scan electrode 102 and the sustain electrode 103 each has a transparent electrode "a" made of a transparent ITO material and a bus electrode "b" made of a metal material, and the scan and sustain electrodes 102, 103 are formed in pairs. The scan electrodes 102 and the sustain electrodes 103 are covered with one or more dielectric layers 104 to limit a discharge current and to provide insulation among the electrode pairs. A protection layer 105, on which magnesium oxide (MgO) is deposited to facilitate a discharge condition, is formed on the dielectric layer 104.
On the rear substrate 110, barrier ribs 112—of a stripe type or well type—forming a plurality of discharge spaces, i.e., discharge cells, are arranged in a parallel manner. Further, a plurality of address electrodes 113, which perform address discharging to generate the vacuum ultraviolet rays, are disposed parallel to the barrier ribs 112. Red (R), green (G) and blue (B) phosphors 114, which emit visible rays for image display upon address discharging, are coated on a top surface of the rear substrate 110. A low dielectric layer 115 to protect the address electrodes 113 is formed between the address electrodes 113 and the phosphors 114.
A method for implementing image gray scales using the related art plasma display panel will now be described with reference to FIG. 2. As shown in FIG. 2, in order to represent the gray scales of the image in the related art plasma display panel, one frame period is divided into a plurality of sub-fields each having a different number of emission. Each sub-field is subdivided into a reset period for initializing all cells, an address period for selecting discharged cells, and a sustain period for implementing gray scales according to the number of discharges. For example, if it is desired to display an image with 256 gray scales, a frame period (16.67 ms) corresponding to 1/60 second is divided into eight sub-fields SF1 to SF8 as shown in FIG. 2. Each of the eight sub-fields SF1 to SF8 is subdivided into the reset, address and sustain periods as indicated above.
The reset period and the address period of each of the sub-fields are the same for every sub-field. Address discharge for selecting cells to be discharged is generated due to a voltage difference between the address electrodes 113 and transparent electrodes "a" of the scan electrodes 102. The sustain period increases by a ratio of 2n (where, n=0, 1, 2, 3, 4, 5, 6, 7) in each of the sub-fields. Because the sustain period is varied in each sub-field, the gray scale of an image is represented by adjusting the sustain period of each of the sub-fields, i.e., by adjusting the number of sustain discharges. A driving waveform in the method of driving the related art plasma display panel will be described below with reference to FIG. 3.
Referring to FIG. 3, the plasma display panel is driven in the following manner: each sub-field is divided into a reset period for initializing all cells, an address period for selecting cells to be discharged, a sustain period for maintaining the discharge of the selected cells, and an erase period for erasing wall charges within discharged cells.
The reset period is further divided into a set-up period and a set-down period. In the set-up period of the reset period, a ramp-up waveform Ramp-up is applied to all scan electrodes 102 simultaneously. A weak dark discharge is generated within discharge cells of the entire screen due to the ramp-up waveform. The set-up discharge causes positive polarity wall charges to be accumulated on the address electrodes 113 and the sustain electrodes 103 and also causes negative polarity wall charges to be accumulated on the scan electrodes 102.
In the set-down period of the reset period, a ramp-down waveform Ramp-down is applied to all scan electrodes 102. The ramp-down waveform is such that the voltage on the scan electrodes 102 falls from a positive voltage that is below the peak voltage of the ramp-up waveform to a voltage below the ground level voltage GND. The ramp-down waveform applied to the scan electrodes 102 causes a weak erase discharge to occur within the cells. As a result, excessive wall charges formed on the scan electrodes 102 are sufficiently erased. The set-down discharge also causes wall charges to remain within the cells uniformly to the degree in which stable address discharge can be generated.
In the address period of each sub-field, while a negative scan pulse is sequentially applied to the scan electrodes 102, a positive data pulse—synchronized with the negative scan pulse—is applied to the address electrodes 113. As a voltage difference between the scan pulse and the data pulse and a wall voltage generated in the reset period are added, address discharging is generated within the discharge cells to which the data pulses are applied. Further, wall charges of the degree in which discharge can be generated when a sustain voltage Vs is applied are formed within the cells selected by the address discharging. A positive polarity voltage Vz is applied to the sustain electrodes 103 so that erroneous discharge is not generated with the scan electrode 102 by reducing a voltage difference with the scan electrode 102 during the address period.
In the sustain period, a sustain pulse Sus is alternately applied to the scan electrodes 102 and the sustain electrodes 103. In the cells selected by address discharging, a sustain discharge, i.e., a display discharge, is generated between the scan electrodes 102 and the sustain electrodes 103 whenever each sustain pulse is applied as the wall voltage within the cells and the sustain pulse are added.
After the sustain discharge is completed, in the erase period, an erase ramp waveform Ramp-ers, which has a narrow pulse width and a low voltage level, is applied to the sustain electrodes 103 so that wall charges remaining in the cells of the entire screen are erased.
In this related art driving waveform, application time points of the data pulses applied to the address electrodes 113 in the address period will be described with reference to FIG. 4. As shown in FIG. 4, the data pulse applied in the address period rises at a tilt and also falls at a tilt. This related art data pulse has a voltage-rising time or duration (tup) and a voltage-falling time or duration (tdown) that are relatively short. For example, the tup and tdown times of the related art data pulse can be approximately 20 ns.
Furthermore, the related art data pulse is the same for all address electrodes. This situation will be described with reference to FIG. 5, which is a view for explaining the voltage-rising time and the voltage-falling time of data pulses applied to the address electrodes during the address period in the related art driving waveform.
As shown in FIG. 5, the data pulses with identical voltage-rising times tup and identical voltage-falling times tdown are applied to all address electrodes X1 to Xm. In FIG. 5, the data pulses applied to address electrodes X1, X2, X3 . . . Xm all begin rising at a time point t1 and then reach the highest point at a time point t2. That is, the voltage-rising time tup is t2−t1 for all electrodes. Furthermore, the data pulses all begin falling at a time point t3 and then reach the lowest point at a time point t4. That is, the voltage-falling time tdown is t4−t3 for all electrodes.
As such, in the related art, the tup and tdown times of the data pulses are relatively short and same for all data pulses applied to all the address electrodes. As a result, a significant amount of noise is generated. Noise generation due to the data pulses will be described with reference to FIG. 6.
From FIG. 6, it can be seen that a relatively large amount of noise is generated in the data pulses applied to the address electrodes. That is, when the data pulse rises, some noise is generated in the direction of the rising voltage (overshoot). When the data pulse falls, some noise is generated in the direction of the falling voltage (undershoot). The noise is generated due to the coupling of the data pulses applied to address electrodes at points where the voltage of the data pulses abruptly change, i.e. at points where the voltage falls and where the voltage rises.
If a difference between the highest value of rising noise and the lowest value of falling noise, i.e., the amount of noise Vr, becomes excessive, the address discharge generated during the address period becomes unstable. As a result, driving efficiency of plasma display panel is reduced. Also, electrical damage to the data drive ICs that supply the data pulses to the address electrodes can occur. Components having high voltage ratings can be used to prevent such electrical damage to the data drive ICs. However, utilizing such components increases the cost of production.

Plasma display apparatus and driving method thereof


A method for growing a nitride crystal and a crystalline composition selected from one of AlN, InGaN, AlGaInN, InGaN, and AlGaNInN is provided. The composition comprises a true single crystal, grown from a single nucleus, at least 1 mm in diameter, free of lateral strain and tilt boundaries, with a dislocation density less than about 104 cm−2.

Various methods for growing high quality gallium nitride (GaN) crystals are being developed by laboratories across the world. However, other nitride crystals, such as AlN and InN, would be very useful as substrates for applications such as UV-LEDs, UV-photodetectors, and field-effect transistors but are not currently available. The bandgap of AlN (6.2 eV) is much larger than that of GaN (3.4 eV), making it the substrate of choice for deep-UV light emitters and detectors. In addition, the thermal conductivity is significantly higher than that of GaN, potentially making it superior as a substrate for certain electronic devices, such as field-effect transistors (also known as high electron mobility transistors). InN has the highest electron velocity of any known nitride, and may be useful for high-frequency devices.
There is substantial prior art in the growth of crystalline nitrides other than GaN, but none of it employs supercritical solvents at pressures above about 5 kbar. None of the existing approaches are yet commercially viable from the standpoints of simultaneous requirements for: (i) producing large (≧2″ in diameter), single-crystal boules suitable for slicing into wafers, as with conventional silicon and gallium arsenide substrates; (ii) producing high-quality crystals, as characterized by low concentrations of impurities and dislocations and narrow x-ray rocking curves; and (iii) growth rates that are high enough for moderate-cost production.
The technique for bulk AlN growth that has probably provided the largest crystals grown to date is sublimation-recondensation, as disclosed originally by Slack and McNelly [J. Cryst. Growth 34, 263 (1976) and 42, 560 (1977)]. However, this technique requires extremely high temperatures (ca. 2250° C.), involves contact with a crucible, which can cause stresses and contamination, and tends to produce crystals with substantial concentrations of dislocations, low-angle grain boundaries, and polycrystalline domains. Several authors have disclosed growth of small AlN crystals in supercritical ammonia, notably Peters [J. Cryst. Growth 104, 411 (1990)], Kolis et al. [Mater. Res. Soc. Symp. Proc. 495, 367 (1998)], Dwilinski et al. [Diamond Relat. Mater. 7, 1348 (1998)], and Demazeau et al. [High Pressure Research 18, 227 (2000)]. However, these latter approaches were limited by the type of apparatus available (autoclaves) to a maximum pressure of 2-5 kbar and a maximum temperature of 400-600° C., produced crystals in the micron size range, and the growth rate was very low. AlN growth in a liquid flux, such as Ca3N2 [U.S. Pat. No. 3,450,499] or Na3AlF6 [R B Campbell et al., Technical Report AFAPL-TR-67-23 (1967)] has also been reported, but in each case the crystals produced were no larger than 1 mm.
Single crystal growth of InN has not been reported by any method, to the best of our knowledge. The inventors have disclosed methods for growing high-quality GaN crystals in supercritical ammonia. However, straightforward application of these methods to the growth of AlN were unsuccessful. Al and In are both more oxophilic than Ga, and the present inventors have discovered that reduction of the oxide contents of the raw material was necessary in order for successful crystal growth in supercritical ammonia.
Techniques for preparing high quality nitride crystal are provided herein.


A food processing equipment particularly adapted for frying treatment of various kinds of vegetable root, meat and marine object which are first sliced and then disposed in a drying basket for removal of moisture; afterwards, the processed food is submerged in fructose for a period of time in a frying tank, and then the fructose is discharged out of the tank with frying oil charged thereinto subsequently. The food is then fried in the frying tank for some time. The fried food taken out of the frying oil is first shaken up and down and rotationally so as to get the same deoiled in a vacuum state. The deoiled food is then blown cool by way of cold air produced by a cooling machine. Next, the cooled food is carefully seasoned so that the original color and flavor and nutrition of the processed food can be well maintained and the same is tasted crispy and can be reserved for a longer time.

The present invention relates to a food processing equipment which is particularly adapted for frying various kinds of vegetable root and meat and marine product in such a manner that the color and flavor of the fried food can be maintained, and the same tastes crispy and can be preserved for a longer time.
Generally, the conventional food frying process is carried out directly in the air, and the outcome of the fried food is usually not satisfactory and there are number of disadvantages given as below:
1. Frying food directly in a frying pan will often cause the skin of the same brown or scorched, with the core thereof still raw but the skin deeply fried. PA0 2. Oil used for frying food at high temperature will be oxydized easily so that addition of anti-oxidant in the oil becomes necessary; but the so treated oil is easily turned black and sour in one aspect and the food fried in such oil will be harmful to human health in another. PA0 3. Direct frying food in hot oil will cause the original color, flavor and nutrition thereof destroyed, and the oil content in the food is relatively high, making the taste of the food too oily. PA0 4. Generally, such fried food can only be reserved for 6 months.


Multielement capacitors have at least one metal capacitor and at least one ceramic capacitor with common terminals in a common case. The preferred metal capacitance elements have an effective series capacitance of at least 1 microfarad at frequencies of up to 100 kHz. The individual metallic capacitance elements exhibit an ESR of less than 100 milliohms at 100 kHz and a dissipation factor (DF) of less than about 6% at 120 Hz. The ceramic capacitance elements useful in the invention have an equivalent series capacitance of at least about 0.1 microfarads at frequencies of up to about 100 MHz. The individual ceramic capacitance elements have an ESR of less than 20 milliohms at 1 MHz and a dissipation factor of less than 10% at 1 kHz.

The development of higher speed microprocessor chips and the miniaturization of the power conversion circuitry (usually switch-mode supplies) used to power these chips have lead to an increase in the demand for small footprint, low ESR capacitors. These capacitors need to minimize voltage output fluctuations at the switching frequency and harmonics of the power supply. They also are used to provide local power to the microprocessor chip to maintain power supply voltages at acceptable limits as the current demands of the processor shift.
Power supplies operating at switching frequencies of 100 kHz and above are one such type of device. It is important that the capacitor exhibit low impedance and equivalent series resistance (ESR) at these frequencies as well as low equivalent series inductance (ESL). The capacitors used in such power supplies should have large low frequency charge storage so the power supply can experience momentary variations in input power without disturbing the output.
Previously, electronics manufacturers have used combinations of metal oxide and ceramic capacitors that are mounted in parallel and connected by a variety of connection circuits to provide charge storage and acceptable high frequency impedance/ESR performance. Unfortunately, the available space for mounting such systems of chips is diminishing as manufacturers design ever smaller and more efficient systems. Manufacturers must also incur costs per mounted connection to assemble such circuits, and variations in the interconnecting circuitry cause differences in the resulting ESL between board manufacturers.
It would be advantageous to have a capacitor element with low impedance and ESR at high frequencies that could be mounted in a minimum amount of space on a circuit board.
It would also be beneficial to have a means for reducing variations in ESL for parallel mounted metal oxide and ceramic capacitors.


A lead frame and a semiconductor device having a lead frame are disclosed. The lead frame is provided with a mount bed to mount a semiconductor chip, first and second lead terminals and first and second extension portions of band-shapes. The first and the second extension portions extend from sides of the first and second lead terminals and are bent. An electronic component is attached to Tip portions of the first and the second extension portions with connection conductors interposed in between.

A resin-sealed semiconductor device is widely used. The resin-sealed semiconductor device seals a semiconductor chip with resin.
In some cases, a chip component, which is a passive element such as a capacitor or a resistor, is provided in addition to a semiconductor chip in a resin-sealed semiconductor device.
A mounting portion may be formed between lead terminals extend portioning in parallel to each other, in order to mount a chip component. The chip component is mounted on the mounting portion with a conductive paste interposed in between. The chip component is fixed to the lead frame by heating the conductive paste to a curing temperature.
The conductive paste is a mixture of silver filler and epoxy resin, for example. When the conductive paste is thermally cured, the conductive paste may crack due to thermal stress caused by a difference in thermal expansion coefficient between the chip component and the lead frame.
Furthermore, when epoxy resin is prepared for the conductive paste and is cured, the cured epoxy resin may be embrittled with exposure to a high temperature. It may result in causing reduction in adhesion performance and impact resistance.
Japanese Patent Application Publication No. 6-120406 and Japanese Patent Application Publication No. 9-36298 disclose a semiconductor device capable of avoiding generation of thermal stress during curing.
The semiconductor device disclosed in the former patent publication is provided with a groove or a step as a stress absorber in an inner lead portion of a lead frame on which a chip component is mounted.
The semiconductor device mentioned in the latter patent publication has an extension portion formed in a lead frame. The extension portion extend portions to form a band shape which corresponds to a shape of an electrode of a chip component. The tip of the extension portion functions as a mounting portion to mount the electrode. A narrow-width portion, which has a width smaller than that of the mounting portion, is formed at a base end portion of the extension portion.
Such structures of the semiconductor devices disclosed in the above patent publications allow the semiconductor devices to bear thermal stress when the epoxy resin is cured. However, the semiconductor devices may be insufficient to bear heat or physical impact which is applied after curing. In the semiconductor device, a conductive paste, which fixes a chip component to a lead frame, may be cracked to cause the semiconductor devices to be electrically open. In some cases, the chip component may peel off, which shows poor reliability of the semiconductor devices.

Lead frame and semiconductor device provided with lead frame


A computation apparatus includes a plurality of memory cells and a plurality of sense amplifiers, in which each of the memory cells includes a memory circuit and a calculation circuit. The memory circuits of the memory cells are configured to receive input values from a plurality of word lines, generate a computation result based on the input values and output the computation result to a bit line. The calculation circuits of the memory cells are configured to receive calculation input values from a plurality of calculation word lines, generate calculation output values based on the calculation input values, and output the calculation output values to a plurality of calculation bit lines. The sense amplifiers are configured to sense the calculation output values from the calculation bit lines to generate sensed values, wherein a value of the computation result is determined based on the sensed values and the calculation output values.

In CIM applications, a computation operation may be performed by memory cells of a memory device to obtain a computation result. For example, inputs are provided to word lines that are coupled to the memory cells, and the outputs from bit lines that are coupled to the memory cells are sensed. In a sensing scheme, an analog-to-digital converter (ADC) is coupled to the bit lines to receive the outputs and to convert the outputs to generate a computation result of the computation operation. However, a circuit structure of the ADC is complicated, and a circuit area and a power consumption of the ADC are relatively large. As such, a creative design that may eliminate the necessity of the ADC in the reading scheme is highly desirable.

Computation apparatus and method using the same

Taiwan Semiconductor Manufacturing Company, Ltd.


A method for depositing silicon dioxide on the surface of a substrate or the like using a nitrogen-containing precursor is disclosed herein. In a preferred implementation the deposition is performed using an atmospheric pressure reactor, into which is directed toward the substrate surface a stream of source gas comprised of ozonated oxygen. A stream of a nitrogen-containing precursor such as, for example, hexamethyldisilazane (HMDS) is also directed into the reactor toward the substrate surface. In addition, a stream of a nitrogen-containing separator gas is directed into the reactor between the streams of precursor and source gases. The inventive deposition method has been shown to result in improved film nucleation on a variety of substrate surfaces.

Chemical vapor deposition of silicon dioxide films has been employed in semiconductor fabrication for several years. Such films have been produced by using, for example, conveyorized atmospheric pressure chemical vapor deposition (APCVD) apparatus. An exemplary APCVD device is disclosed in U.S. Pat. No. 4,834,020, entitled "Atmospheric Chemical Vapor Deposition Apparatus", which is assigned to the assignee of the present invention, and which is herein incorporated by reference.
In the early development of silicon dioxide films silane and oxygen were often used as source gases. Unfortunately, the use of particular deposition precursors in these initial efforts tended to impede film conformance to various types of surface features. Organosilane precursors such as tetraethylorthosilicate (TEOS) have since been used to improve surface conformity, but have generally required relatively high deposition temperatures.
In recently developed techniques, ozonated oxygen has been employed as a source gas with TEOS and other organosilane precursors in order to obtain deposition of silicon dioxide at reduced temperatures (300.degree.-500.degree. C.). As is known, the use of ozonated oxygen allows deposition to be initiated at low temperatures without requiring plasma excitation. Films created using these recently developed techniques have generally exhibited improved topographical conformance, thereby enabling the production of films with smooth surfaces. However, such films often do not readily grow upon commonly encountered surfaces such as thermal silicon dioxide or fluorine-contaminated metals. Such inhibition of nucleation can result in reduced deposition rates and increased film porosity.

Chemical vapor deposition of silicon dioxide using hexamethyldisilazane


A roller for a roller grinder, the roller including a shaft and a grinding shell in the form of a tubular sleeve and having an inner face to be retained around the shaft. The roller grinder is characterized in that the shaft includes two shaft parts, each shaft part having a respective inner end portion, wherein the inner end portions are arranged to be positioned facing each other and include coupling portions arranged to couple the inner end portions of the respective shaft parts to each other, thereby forming the shaft. The disclosure further relates to a method for assembling a roller for a roller grinder, the roller including a shaft and a grinding shell in the form of a tubular sleeve and having an inner face to be retained around the shaft.

High pressure roller grinders for grinding rock and the like are for obvious reasons subjected to a high level of wear from the processed material. Each roll of a roller grinder therefore commonly utilizes an outer cylindrical grinder shell made of a wear resistant material covering the rolls. The grinder shell eventually has to be replaced when worn down by the processed material, causing an interruption of the operation of the equipment.
The grinding or crushing shell has to be tightly mounted around the hub portion of the shaft, with a high friction between the parts to avoid loosening of the shell during operation of the grinder. The hub portion of the shaft may have a cylindrical shape or may be slightly conical to enable easy mounting and dismounting of the grinder shell. The conicity is preferably minimal, to prevent the grinding shell from being undesirably released during operation of the grinder.
In a known constructive solution, the outer grinding shell is designed to be mounted around the hub portion of the shaft by means of thermal expansion-contraction. The outer grinding shell is heated to present a thermal expansion sufficient to allow it to axially slide around the shaft, until reaching the mounting position, in which its cooling and shrinkage produce its retention, by high interference, around the hub portion of the shaft, the hub portion being generally cylindrical.
This known mounting solution presents some inconveniences. The outer grinding shell can crack upon cooling, particularly when it is made of a hard high carbon steel, and it can lose its uniformity and its cylindrical tubular geometric form, due to the stress caused by application of heat. The mounting solution by thermal expansion-contraction of the outer grinding shell also presents inconveniences when dismounting the grinding shell from the hub portion of the shaft. The dismounting is extremely difficult due to the high level of frictional interference between the two parts. This difficulty is so great and time consuming that it is frequently preferred to replace the whole shaft-grinding shell assembly, undesirably increasing the costs of replacing the already worn out grinding shells. This problem is particularly cost inducing when the frequency of these replacements is high due to a high level of wear of the outer shell. It is also frequent, in such cases, that the shaft is damaged during the dismounting procedure, further increasing the replacement costs of the grinding shell. In many cases, the bearings, which are usually an expensive part, are integrated in the shaft assembly, further increasing the cost of the replacement when not being able to dismount the outer shell.
There are also known mounting solutions which utilize an internally conical grinding shell operating around a wedge provided between the hub portion of the shaft and the grinding shell and which is forced towards the central region of the roller, producing inward and outward radial forces against the shaft and against the grinding shell, respectively, producing the necessary high level of frictional interference between the grinding shell and the shaft. Although overcoming the inconveniences related to the mounting by thermal expansion-contraction, the utilization of a wedge and an internally conical grinding shell presents the inconvenience of making the axial and radial alignments difficult and the replacement operations of the grinding shell complex and costly.
U.S. Pat. No. 5,060,874 describes a mounting solution according to which each shaft medianly carries a pair of externally conical hubs, each being operatively associated with shrink discs, wedges and an expansion ring, to establish a high level of frictional interference between the grinding shell and the shaft, without requiring thermal expansion-contraction of the recipient. This prior solution requires a large number of components, which undesirably raises its cost.

Roller for high pressure roller grinder, roller grinder, and method for assembling a roller for a roller grinder


The invention provides methods for inducing an immune response in a vertebrate host against a protozoan parasite, comprising administering to the host a live protozoan parasite that is genetically engineered to disrupt a stage-specific gene function that is required by the protozoan parasite to establish a secondary infection in the vertebrate host. Representative protozoan parasites belong to the phyla Apicomplexa and Kinetoplastida. The vertebrate host may be a mammal or a bird.

Malaria has a tremendous impact on human health, killing millions annually and the disease is a major impediment for social and economic development of nations in malaria-endemic areas, particularly in sub-Saharan Africa (Sachs & Malaney (2002) Nature 415:680-85). Malaria is a mosquito-borne disease that is transmitted by inoculation of the Plasmodium parasite sporozoite stage. Sporozoites invade hepatocytes (Kappe et al (2003) Trends Parasitol. 19:135-43), transform into liver stages, and subsequent liver stage development ultimately results in release of pathogenic merozoites (Shortt & Garnham (1948) Nature 161:126).
Because an effective "subunit" malaria vaccine has remained elusive and the complexity of the malaria parasite Plasmodium might preclude the successful development of such a vaccine, whole organism vaccine approaches against malaria have lately found renewed interest (Hoffman (2004) Nature 430:940-941). The feasibility of such a vaccine has been demonstrated in animal models and subsequently in humans by induction of sterile protective immunity through inoculation with irradiation-attenuated parasites (Nussenzweig et al. (1967) Nature 216:160-62; Hoffman et al. (2002) J. Infect. Dis. 185:1155-64). Liver stages are a prime malaria vaccine target because they can be completely eliminated by sterilizing immune responses, thereby preventing malaria infection (Hoffman & Doolan (2000) Nat. Med 6:1218-9). The recent availability of complete Plasmodium genome sequences (Gardner et al. (2002) Nature 419:498-511; Carlton et al. (2002) Nature 419:512-9) may now permit the development of live-attenuated parasites by more precise and defined genetic manipulations (WO 2004/045559 A2).
Using expression profiling, we identified genes that are specifically expressed during the pre-erythrocytic part of the parasite life cycle (Matuschewski et al. (2002) J. Biol. Chem. 277:41948-53; Kaiser et al. (2004) Mol. Microbiol. 51:1221-32). A number of pre-erythrocytic genes named UIS (up-regulated in infective sporozoites) also showed up-regulation in sporozoites when they gain infectivity for the mammalian host (Matuschewski et al. (2002) J. Biol. Chem. 277:41948-53).
Often overshadowed by Plasmodium, other organisms within the phylum Apicomplexa, as well as protozoan organisms within the phylum Kinetoplastida, cause significant diseases in humans and animals. For example, protozoan organisms within the genuses of Toxoplasma, Neospora, Eimeria, Theileria, Babesia, Cryptosporidium, Sarcocystis, Leucocytozoon, Leishmania, and Trypansoma all devastate susceptible vertebrate host populations and severely impact economic development in endemic regions. In general, these protozoan organisms are eukaryotic, unicellular, parasit that have a life cycle including at least two infective stages in a susceptible vertebrate host, one of which cause the secondary infection that is the hallmark of the protozoan disease.
There is a need in the art for vaccines that protect against protozoan diseases. The present invention addresses this need and others.

Live genetically engineered protozoan vaccine


Embodiments of the invention provide an array substrate, a display panel, a display device and a method for driving an array substrate. The array substrate includes gate lines, data lines, pixel TFTs and pixel electrodes and compensation capacitors on the array substrate; in every two adjacent rows of gate lines in at least a part of the rows on the array substrate, pixel TFTs connected with one gate line are a first type of TFTs, and pixel TFTs connected with an other gate line are a second type of TFTs; and in the at least a part of the rows, each of the pixel electrodes is arranged correspondingly with one of the compensation capacitors, and each of the compensation capacitors has one end electrically connected to the pixel electrode corresponding thereto and another end electrically connected to a gate line in a next row.

An array substrate of a Thin Film Transistor-Liquid Crystal Display (TFT-LCD) is driven by a matrix of rows and columns, which is formed by intersecting N rows of gate lines and M columns of data lines, to control each pixel electrode in the matrix of rows and columns. Conventional solutions exist, but unfortunately they are inadequate for reasons explained below, and it is desirable to have new and improved systems and methods.

Array substrate, display panel, display device and method for driving array substrate

XIAMEN TIANMA MICRO-ELECTRONICS CO., LTD.


The invention provides a biosynthetic gene cluster for mitomycin, for example, a mitomycin biosynthetic cluster from organisms such as Streptomyces, for instance, S. lavendulae, as well as methods of using gene(s) within the cluster to alter antibiotic biosynthesis and to prepare a polyketide synthase.

Streptomyces are filamentous Gram-positive soil bacteria with a nucleotide base composition greater than 70 mole % G+C (Stackebrandt and Woese, 1981). They produce a wide array of biologically active compounds including over two thirds of the commercially important natural product metabolites (Alderson et al., 1993; Bevax, 1998). Genetic information accumulated over the past 15 years has demonstrated that genes encoding enzymes for natural product assembly are clustered on the Streptomyces genome (Martin, 1992). In addition, one or more pathway-specific transcriptional regulatory genes, and at least one resistance gene are typically found within the antibiotic biosynthetic gene cluster (Chater, 1992). Heterologous hybridization with gene probes based on highly conserved biosynthetic enzyme amino acid sequences has been useful to clone antibiotic biosynthetic genes (Hopwood, 1997; Seno and Baltz, 1989; Turgay and Marahiel, 1994).
The mitomycins are a group of natural products that contain a variety of functional groups, including aminobenzoquinone and aziridine ring systems. One representative of the family, mitomycin C (MC), was the first recognized bioreductive alkylating agent. In particular, since its discovery and demonstration of anticancer activity in the 1960s, many aspects of the chemistry and biology of MC have been investigated. This has provided detailed information on its unprecedented molecular mechanism, unique biological and pharmacological properties, drug resistance, and bioactive analogues (Hata et al., 1956; Verweij, 1997). MC is regarded as the prototype natural product alkylating agent whose activity is dependent on the reductive activation (either chemically, such as low pH, or enzymatically, such as DT-diaphorase, NADH cytochrome c reductase) (Boxer, 1997; Cummings et al., 1998). Activated MC crosslinks double-stranded DNA, which in turn induces diverse biological effects including selective inhibition of DNA synthesis, mutagenesis, induction of DNA repair (SOS response), sister chromatid exchange, signal transduction, and induction of apoptosis (Tomasz and Palem, 1997). Tumor hypoxia and the increased expression of bioreductive enzymes in malignant cells create a selective environment for drug activation and make MC an attractive agent for anti-tumor therapy (Spanswick et al., 1998). MC has become one of the most effective antitumor drugs against non-small cell lung carcinoma and other soft tumors, as well as a clinically important component of combination cancer chemotherapy and radiotherapy of solid tumors (Henderson, 1993).
In addition to its biological and pharmacological importance, MC is prominent because its molecular mechanism represents a model for structurally related antitumor antibiotics such as porfiromycin (Pan and Iracki, 1988), mitiromycin (Wakaki et al., 1958), FR66979 (Paz and Hopkins, 1997), FR900482 (Williams et al., 1997), FK973 (Hirai et al., 1994), and FK317 (Naoe et al., 1998), as well as structurally unrelated bioreductive agents such as EO9 (Smitskampwilms et al., 1996), and tirapazamine (Evans et al., 1998). Numerous MC derivatives have been synthesized and tested for enhanced activities, including the recently identified selective protein tyrosine kinase inhibitor, 1a-docosahexaenoyl MC (Kasai and Arai, 1995; Shikano et al., 1998).
Streptomyces lavendulae produces MC. The molecule has an unusual structure comprised of aziridine, pyrrolizidine, pyrrolo-(1,2a)-indole, and amino-methylbenzoquinone rings to give the mitosane nucleus (Webb et al., 1962). The mitosane core of MC was shown to be derived from the junction of an amino-methylbenzoquinone (mC7N unit) and hexosamine (C6N unit) (Hornemann, 1981). The C6N unit consists of carbons 1, 2, 3, 9, 9a, 10, with the aziridine nitrogen derived intact from D-glucosamine (Hornemann et al., 1974).
The mC7N unit in MC and the ansamycins is derived from 3-amino-5-hydroxybenzoic acid (AHBA) (Becker et al., 1983; Kibby and Richards, 1981). AHBA was first shown to be incorporated into the ansamycin antibiotic actamycin (Kibby et al., 1980). Subsequently, it was confirmed as an efficient precursor for rifamycin (Becker et al., 1983; Kibby and Rickards, 1981; Ghilsalba and Neuesch, 1981), geldanamycin (Potgieter, 1983), ansamitocin (Hatano et al., 1982), ansatrienin (Wu et al., 1987), streptovaricin (Staley and Rinehart, 1991) and naphthomycin A (Lee et al., 1994). Anderson et al. (1980) demonstrated that [carboxy-13C] AHBA could be efficiently and specifically incorporated into the C-6 methyl group of porfiromycin, which contains the same mitosane core as MC. Incorporation experiments with radiolabeled precursors have demonstrated that the mitosane core of MC was derived from the junction of AHBA and D-glucosamine (Anderson et al., 1980; Hornemann, 1981).
Meanwhile the Oxe2x80x94 and Nxe2x80x94 (but not Cxe2x80x94) methyl groups were shown to be derived from L-methionine, while the C-10 carbamoyl group came from L-arginine or L-citrulline (Bezanson and Vining, 1971; Hornemann and Eggert, 1975; Hornemann et al., 1974). [14C]-labeled precursor feeding studies with D-glucose, pyruvate and D-erythrose indicated that de novo biosynthesis of AHBA resulted directly from the shikimate pathway. However, no incorporation into the mC7N unit of either MC (Hornemann, 1981) or the ansamycin antibiotics (Chiao et al., 1998) was found from labeling studies with shikimic acid, the shikimate precursor 3-dehydroquinic acid, or the shikimate derived amino acids. These results led to the hypothesis of a modified shikimate pathway, in which a 3-deoxy-D-arabino-heptulosonic acid-7-phosphate (DAHP) synthase-like enzyme catalyzes the conversion to 3,4-dideoxy-4-amino-D-arabino-heptulosonic acid-7-phosphate (amino-DAHP), to give the ammoniated shikimate pathway (Kim et al., 1992). Floss (1997) provided strong support for this new variant of the shikimate pathway by showing that aminoDAHP, 5-deoxy-5-amino-3-dehydroquinic acid (aminoDHQ), and 5-deoxy-5-amino-3-dehydroshikimic acid (aminoDHS) could be efficiently converted into AHBA by a cell-free extract of Amycolatopsis mediterranei (rifamycin producer), in contrast to the normal shikimate pathway intermediate DAHP which was not converted (Kim et al., 1992; Kim et al., 1996). Recently, the AHBA synthase (rifK) gene from A. mediterranei has been cloned, sequenced and functionally characterized (Kim et al., 1998).
Little is known regarding the details of the convergent assembly of MC from AHBA and D-glucosamine in S. lavendulae, i.e., whether its de novo biosynthesis is related to the primary metabolic shikimate pathway, an important route in microorganisms and plants for aromatic amino acid biosynthesis (Floss, 1997). In addition, it is unclear how S. lavendulae resists the activity of MC since the preferred MC alkylation sites in DNA are guanine and cytosine, and MC-induced cell death can result from a single crosslink per genome (Tomasz, 1995).
Thus, there is a continuing need for the identification and isolation of antibiotic biosynthetic genes, including genes which confer resistance to antibiotics or result in enhanced production of antibiotics.
The present invention provides an isolated and purified nucleic acid molecule, e.g., DNA, comprising a gene cluster for mitomycin, a variant or a fragment thereof (the mit/mmc gene cluster). As described hereinbelow, the S. lavendulae mitomycin gene cluster includes the mitomycin biosynthetic gene cluster comprising 47 mitomycin biosynthetic genes spanning 55 kb of contiguous DNA. The biosynthetic portion of the gene cluster includes genes that encode polypeptides involved in the generation of biosynthetic precursors, mitosane ring system assembly and functionalization (e.g., methylation, hydroxylation, aminotransfer, carbamoylation, and carbonyl reduction), a mitomycin resistance gene which is different than mrd and the unlinked mcr, as well as several regulatory genes. Gene disruption was employed to further characterize some of the genes. Fourteen of 22 gene disruption mutants affected mitomycin biosynthesis, resulting in abrogation or overexpression of drug production, e.g., targeted genetic disruption of a mitomycin pathway regulator (e.g., mmcW) led to a substantial increase in drug production. It is preferred that the isolated and purified nucleic acid molecule of the invention is nucleic acid from Streptomyces spp., such as Streptomyces lavendulae (e.g., B19/ATCC 27422, NRRL 2564, KY681, ATCC 27423, or PB1000), Streptomyces caespitosus, Streptomyces verticillatus, and Streptomyces sandaensis (FERM-P7654), although isolated and purified nucleic acid molecules from other organisms which produce mitomycin or biological or functional equivalents thereof are also within the scope of the invention. The nucleic acid molecules of the invention are double-stranded or single-stranded.
As described hereinbelow, a 3.8 kb BamHI fragment from the S. lavendulae genome was isolated which comprises three open reading frames (ORFs). One of the ORFs (mitA) showed high similarity to previously identified AHBA synthase genes (Kim et al., 1998), while another (mitB) showed sequence similarity to several prokaryotic and eukaryotic glycosyltransferases. Nucleotide sequence analysis showed that mitA encodes a 388 amino acid protein that has 71% identity (80% similarity) with the rifamycin AHBA synthase from Amycolatopsis mediterranei, as well as with two additional AHBA synthases from related ansamycin antibiotic-producing microorganisms. Gene disruption and site-directed mutagenesis of the S. lavendulae chromosomal copy of mitA completely blocked the production of MC. The function of mitA was confirmed by complementation of a S. lavendulae strain containing a K191A mutation in MitA with 3-amino-5-hydroxybenzoic acid, i.e., MC production was restored when the mitA mutant strain was cultured in the presence of exogenous 3-amino-5-hydroxybenzoic acid. mitB encodes a 272 amino acid protein.
Seven gene products (aminoDHQ synthase (MitP), aminoquinate dehydrogenase (MitT), aminoDHQ dehydratase (MmcF), AHBA synthase (MitA), oxidoreductase (MitG), phosphatase (MitJ), and kinase (MitS)) are likely responsible for assembly of the intermediate 3-amino-5-hydroxybenzoic acid (AHBA) through a variant of the shikimate pathway. However, the gene encoding aminoDAHP synthase, the first presumed enzyme involved in AHBA biosynthesis from phosphoenol pyruvate (PEP) and erythrose 4-phosphate (E4P), is not linked within the mitomycin biosynthetic gene cluster.
A mitomycin resistance determinant (mct) encodes a membrane-associated protein involved in excretion of mitomycin from cells. Disruption of mct by insertional inactivation resulted in a S. lavendulae mutant strain that was considerably more sensitive to MC. Expression of mct in E. coli conferred a 5-fold increase in cellular resistance to MC, led to the synthesis of a membrane associated protein, and correlated with reduced intracellular accumulation of drug. Co-expression of mct and mrd in E. coli resulted in a 150-fold increase in resistance, as well as reduced intracellular accumulation of MC. The results establish that MRD maintains a high affinity for MC and may serve as the primary receptor (participating as an accessory component in a drug export system) for subsequent transport by MCT.
The cloned mitomycin biosynthetic genes are useful to elucidate the molecular basis for the biosynthesis of the mitosane ring system, as well as to. engineer the biosynthesis of novel natural products. Moreover, genetic engineering or overexpression of the transport, resistance and regulatory proteins may lead to higher titers of mitomycin compounds from production cultures.
Preferably, the isolated nucleic acid molecule comprising the gene cluster includes a nucleic acid sequence comprising SEQ ID NO:96 or SEQ ID NO:76, a variant or a fragment thereof, e.g., a nucleic acid molecule that hybridizes under moderate, or more preferably stringent, hybridization conditions to SEQ ID NO:96, SEQ ID NO:76 or a fragment thereof. Moderate and stringent hybridization conditions are well known to the art, see, for example sections 9.47-9.51 of Sambrook et al. (Molecular Cloning: A Laboratory Manual, Cold Spring Harbor Laboratory, Cold Spring Harbor, N.Y. (1989). For example, stringent conditions are those that (1) employ low ionic strength and high temperature for washing, for example, 0.015 M NaCl/0.0015 M sodium citrate (SSC); 0.1% sodium lauryl sulfate (SDS) at 50xc2x0 C., or (2) employ a denaturing agent such as formamide during hybridization, e.g., 50% formamide with 0.1% bovine serum albumin/0.1% Ficoll/0.1% polyvinylpyrrolidone/50 mM sodium phosphate buffer at pH 6.5 with 750 mM NaCl, 75 mM sodium citrate at 42xc2x0 C. Another example is use of 50% formamide, 5xc3x97SSC (0.75 M NaCl, 0.075 M sodium citrate), 50 mM sodium phosphate (pH 6.8), 0.1% sodium pyrophosphate, 5xc3x97Denhardt""s solution, sonicated salmon sperm DNA (50 xcexcg/ml), 0.1% sodium dodecylsulfate (SDS), and 10% dextran sulfate at 42xc2x0 C., with washes at 42xc2x0 C. in 0.2xc3x97SSC and 0.1% SDS.
A preferred nucleic molecule of the invention comprises a nucleic acid sequence encoding a polypeptide including, but not limited to, MitA (e.g., SEQ ID NO:10 encoded by SEQ ID NO:97), MitB (e.g., SEQ ID NO:11 encoded by SEQ ID NO:98), MitC (e.g., SEQ ID NO:12 encoded by SEQ ID NO:99), MitD (e.g., SEQ ID NO:100 encoded by SEQ ID NO:45), MitE (e.g., SEQ ID NO:101 encoded by SEQ ID NO:44), MitF (e.g., SEQ ID NO:102 encoded by SEQ ID NO:43), MitG (e.g., SEQ ID NO:103 encoded by SEQ ID NO:42), MitH (e.g., SEQ ID NO:104 encoded by SEQ ID NO:41), MitI (e.g., SEQ ID NO:105 encoded by SEQ ID NO:40), MitJ (e.g., SEQ ID NO:106 encoded by SEQ ID NO:39), MitK (e.g., SEQ ID NO:107 encoded by SEQ ID NO:38), MitL (e.g., SEQ ID NO:108 encoded by SEQ ID NO:37), MitM (e.g., SEQ ID NO:109 encoded by SEQ ID NO:36), MitN (e.g., SEQ ID NO:110 encoded by SEQ ID NO:35), MitO (e.g., SEQ ID NO:111 encoded by SEQ ID NO:34), MitP (e.g., SEQ ID NO:112 encoded by SEQ ID NO:33), MitQ (e.g., SEQ ID NO:113 encoded by SEQ ID NO:32), MitR (e.g., SEQ ID NO:114 encoded by SEQ ID NO:31), MitS (e.g., SEQ ID NO:115 encoded by SEQ ID NO:30), MitT (e.g., SEQ ID NO:140 encoded by SEQ ID NO:29), MmcA (SEQ ID NO:116 encoded by SEQ ID NO:49), MmcB (SEQ ID NO:117 encoded by SEQ ID NO:50), MmcC (SEQ ID NO:118 encoded by SEQ ID NO:51), MmcD (SEQ ID NO:119 encoded by SEQ ID NO:52), MmcE (SEQ ID NO:120 encoded by SEQ ID NO:53), MmcF (SEQ ID NO:121 encoded by SEQ ID NO:54), MmcG (SEQ ID NO:122 encoded by SEQ ID NO:55), MmcH (SEQ ID NO:123 encoded by SEQ ID NO:56), Mmcl (SEQ ID NO:124 encoded by SEQ ID NO:57), MmcJ (SEQ ID NO:125 encoded by SEQ ID NO:58), MmcK (SEQ ID NO:126 encoded by SEQ ID NO:59), MmcL (SEQ ID NO:127 encoded by SEQ ID NO:60), MmcM (SEQ ID NO:128 encoded by SEQ ID NO:61), MmcN (SEQ ID NO:129 encoded by SEQ ID NO:62), MmcO (SEQ ID NO:130 encoded by SEQ ID NO:63), MmcP (SEQ ID NO:131 encoded by SEQ ID NO:64), MmcQ (SEQ ID NO:132 encoded by SEQ ID NO:65), MmcR (SEQ ID NO:133 encoded by SEQ ID NO:66), MmcS (SEQ ID NO:134 encoded by SEQ ID NO:67), MmcT (SEQ ID NO:135 encoded by SEQ ID NO:68), MmcU (SEQ ID NO:136 encoded by SEQ ID NO:69), MmcV (SEQ ID NO:137 encoded by SEQ ID NO:70), MmcW (SEQ ID NO:138 encoded by SEQ ID NO:71), MmcX (SEQ ID NO:139 encoded by SEQ ID NO:72), MmcY (SEQ ID NO:141 encoded by SEQ ID NO:73), Mct (SEQ ID NO:17 encoded by SEQ ID NO:16), a variant or a fragment thereof, e.g., a nucleic acid molecule that hybridizes under moderate, or more preferably stringent, hybridization conditions to at least one of the nucleic acid sequences identified hereinabove.
The invention further provides an isolated and purified nucleic acid molecule which is linked to a mitomycin biosynthetic gene cluster and which encodes polyketide biosynthetic enzymes, a variant or a fragment thereof. Preferably, the nucleic acid molecule of this embodiment of the invention comprises at least one, preferably at least five, and more preferably at least nine, open reading frames. More preferably, the nucleic acid molecule hybridizes under moderate, or more preferably stringent, hybridization conditions to SEQ ID NO:74, or a portion thereof.
The invention also provides an isolated and purified nucleic acid molecule which is linked to a mitomycin biosynthetic gene cluster and which encodes sugar biosynthetic enzymes, a variant or a fragment thereof. Preferably, the nucleic acid molecule of this embodiment of the invention comprises at least one, preferably at least five, more preferably at least nine, and even more preferably at least twelve, open reading frames. Preferably, the nucleic acid molecule of this embodiment of the invention hybridizes under moderate, or more preferably stringent, hybridization conditions to SEQ ID NO:75, or a portion thereof.
The invention also provides a variant polypeptide having at least about 80%, more preferably at least about 90%, and even more preferably at least about 95%, but less than 100%, contiguous amino acid sequence identity to a polypeptide having an amino acid sequence encoded by SEQ ID NO:76, or a fragment thereof. A preferred variant polypeptide includes a variant polypeptide or fragment thereof having at least about 1%, more preferably at least about 10%, and even more preferably at least about 50%, the activity of the polypeptide having the amino acid sequence comprising SEQ ID NO:10-12, 17 or 100-141. Thus, for example, the activity of a polypeptide having SEQ ID NO:98 can be compared to a variant of SEQ ID NO:98 having at least one amino acid substitution, insertion, or deletion relative to SEQ ID NO:98.
A variant nucleic acid sequence of the invention has at least about 80%, more preferably at least about 90%, and even more preferably at least about 95%, but less than 100%, contiguous nucleic acid sequence identity to a nucleic acid sequence comprising SEQ ID NO:76, or a fragment thereof. The amino acid and/or nucleic acid similarity (or homology) of two sequences may be determined manually or using algorithms well known to the art.
The invention also provides probes and primers comprising at least a portion of the nucleic acid molecules of the invention. The probes or primers of the invention are preferably detectably labeled or have a binding site for a detectable label. Preferably, the probes or primers of the invention are at least about 7, more preferably at least about 15, contiguous nucleotides bases having at least about 80% identity, more preferably at least about 90% identity, to the isolated nucleic acid molecules of the invention. Such probes or primers are useful to detect, quantify, isolate and/or amplify DNA strands with complementary to sequences related to the mitomycin biosynthetic gene cluster, sequences related to those encoding the polyketide biosynthetic enzymes linked to the mitomycin biosynthetic gene cluster, sequences related to those encoding sugar biosynthetic enzymes linked to the mitomycin biosynthetic gene cluster, a variant or a fragment thereof
Also provided is an expression cassette comprising a nucleic acid molecule comprising at least a portion of a mitomycin biosynthetic gene cluster, a nucleic acid molecule which is linked to a mitomycin biosynthetic gene cluster and which encodes polyketide biosynthetic enzymes, a nucleic acid molecule which is linked to a mitomycin biosynthetic gene cluster and which encodes sugar biosynthetic enzymes, a variant or fragment thereof, operably linked to a promoter functional in a host cell. Host cells that have been modified genetically, i.e., recombinant host cells, include host cells comprising an expression cassette, e.g., an expression cassette of the invention, or host cells in which the genome has been genetically manipulated, e.g., by deletion of a portion of, replacement of a portion of, or by disruption of, the host chromosome, so as to reduce or eliminate the expression of a particular mitomycin biosynthetic gene, polyketide biosynthetic gene or a sugar biosynthetic gene of the invention.
One embodiment of the invention is a recombinant host cell, e.g., a bacterial cell, in which a portion of a nucleic acid sequence comprising the mitomycin gene cluster, i.e., the endogenous or native genomic sequence, is disrupted or replaced, for example, by an insertion with heterologous. sequences or substituted with a variant nucleic acid sequence of the invention, preferably so as to result in altered mitomycin synthesis, such as an increase in mitomycin synthesis, and/or production of a novel compound. For example, the invention includes a recombinant host cell in which the mmcW gene is disrupted, for example, by replacement with a selectable marker gene, so as to yield a recombinant host cell having an increase in mitomycin production.
Another embodiment of the invention is a recombinant host cell, the genome of which is augmented by an expression cassette, e.g., via an extrachromosomal element such as a plasmid or by stable integration of the cassette into the host chromosome. Thus, the genome of the recombinant host cell is augmented with at least one mitomycin biosynthetic gene, polyketide biosynthetic gene or a sugar biosynthetic gene of the invention so as to yield an altered level of mitomycin and/or a novel compound(s) relative to the corresponding non-recombinant host cell.
Alternatively, the genome of a recombinant host cell is augmented with a non-mitomycin biosynthetic gene and, optionally, at least one mitomycin biosynthetic gene, polyketide biosynthetic gene or a sugar biosynthetic gene of the invention so as to yield an altered level of mitomycin and/or a novel compound(s) relative to the corresponding non-recombinant host cell. For example, the recombinant host cell may be augmented with pika (see U.S. application Ser. No. 09/105,537, filed Jun. 26, 1998, the disclosure of which is incorporated by reference herein) and pikA expressed in an amount effective to yield a novel compound(s).
Host cells useful to prepare the recombinant host cells of the invention include cells which do not express or do not comprise nucleic acid corresponding to the nucleic acid molecules of the invention, e.g., mitomycin biosynthetic genes, as well as cells which naturally produce mitomycin.
Thus, the invention also provides isolated and purified polypeptides encoded by a nucleic acid molecule of the invention. Preferably, the polypeptide of the invention is obtained from recombinant host cells, e.g., the genome of which is augmented by a nucleic acid molecule of the invention. In addition, expression cassettes and host cells comprising antisense sequences of at least a portion of the mitomycin biosynthetic gene cluster of the invention are envisioned.
In another embodiment of the invention, the isolated and purified nucleic acid molecule which is linked to a mitomycin biosynthetic gene cluster and which encodes polyketide biosynthetic enzymes, e.g., a polyketide synthase, is useful in methods to prepare recombinant polyhydroxyalkanoate monomer synthases and polymers.
Thus, the present invention provides a method of preparing a polyhydroxyalkanoate synthase. The method comprises introducing an expression cassette into a host cell. The expression cassette comprises a DNA molecule encoding a polyketide synthase, operably linked to a promoter functional in the host cell. The DNA molecule is preferably obtained from a mitomycin-producing organism, e.g., a Streptomyces spp. such as S. lavendulae. The DNA molecule encoding the polyketide synthase is then expressed in the cell. Thus, another embodiment of the invention provides a purified recombinant polyketide isolated from a host cell which expresses the synthase.
Another embodiment of the invention is a method of preparing a polyhydroxyalkanoate polymer. The method comprises introducing a first expression cassette and a second expression cassette into a host cell. The first expression cassette comprises a DNA segment encoding a fatty acid synthase in which the dehydrase activity has been inactivated that is operably linked to a promoter functional in the host cell, e.g., an insect cell. The inactivation preferably is via a mutation in the catalytic site of the dehydrase. The second expression cassette comprises a DNA segment encoding a polyketide synthase that is preferably obtained from a mitomycin-producing organism operably linked to a promoter functional in the host cell. The expression cassettes may be on the same or separate molecules. The DNA segments in the expression cassettes are expressed in the cell so as to yield a polyhydroxyalkanoate polymer.
The present invention also. provides an expression cassette comprising a nucleic acid molecule encoding a polyhydroxyalkanoate monomer synthase operably linked to a promoter functional in a host cell. The nucleic acid molecule comprises a plurality of DNA segments. Thus, the nucleic acid molecule comprises at least a first and a second DNA segment. The first DNA segment encodes a first module and the second DNA segment encodes a second module, wherein the DNA segments together encode a polyhydroxyalkanoate monomer synthase. No more than one DNA segment is derived from the eryA gene cluster of Saccharopolyspora erythraea. It is also preferred that the first DNA segment comprises a module from a mitomycin-producing organism, e.g., Streptomyces spp. The nucleic acid molecule may optionally further comprise a third DNA segment encoding a polyhydroxyalkanoate synthase. Alternatively, a second nucleic acid molecule encoding a polyhydroxyalkanoate synthase may be introduced into the host cell.
Also provided is an isolated and purified DNA molecule. The DNA molecule comprises a plurality of DNA segments. Thus, the DNA molecule comprises at least a first and a second DNA segment. The first DNA segment encodes a first module and the second DNA segment encodes a second module. Together the DNA segments encode a recombinant polyhydroxyalkanoate monomer synthase. It is preferred that no more than one DNA segment is derived from the eryA gene cluster of Saccharopolyspora erythraea. Also, it is preferred that no more than one module is derived from the gene cluster from Streptomyces hygroscopicus that encodes rapamycin or the gene cluster that encodes spiramycin. A preferred embodiment of the invention employs a first DNA segment comprising a module from a mitomycin-producing organism. A further preferred embodiment of the isolated DNA molecule of the invention includes a DNA segment encoding a polyhydroxyalkanoate synthase.
Further provided is a method of preparing a polyhydroxyalkanoate polymer. The method comprises introducing a first DNA molecule and a second DNA molecule into a host cell. The first DNA molecule comprises a DNA segment encoding a recombinant polyhydroxyalkanoate monomer synthase. The recombinant polyhydroxyalkanoate monomer synthase comprises a plurality of modules. Thus, the monomer synthase comprises at least a first module and a second module. The first DNA molecule is operably linked to a promoter functional in a host cell. The second DNA molecule comprises a DNA segment encoding a polyhydroxyalkanoate synthase operably linked to a promoter functional in the host cell. It is preferred that at least one module is from a mitomycin-producing organism. The DNAs encoding the recombinant polyhydroxyalkanoate monomer synthase and polyhydroxyalkanoate synthase are expressed in the host cell so as to generate a polyhydroxyalkanoate polymer.
Yet another embodiment of the invention is an isolated and purified DNA molecule. The DNA molecule comprises a plurality of DNA segments. That is, the DNA molecule comprises at least a first and a second DNA segment. The first DNA segment encodes a fatty acid synthase and the second DNA segment encodes a module of a polyketide synthase. A preferred embodiment of the invention employs a second DNA segment comprising a module of a polyketide synthase from a mitomycin-producing organism such as Streptomyces.
Also provided is a method of providing a polyhydroxyalkanoate monomer synthase. The method comprises introducing an expression cassette into a host cell. The expression cassette comprises a DNA molecule encoding a polyhydroxyalkanoate monomer synthase operably linked to a promoter functional in the host cell. The monomer synthase comprises a plurality of modules. Thus, the monomer synthase comprises at least a first and second module which together encode the monomer synthase. A preferred embodiment of the invention employs a module from a mitomycin-producing organism. Optionally, the expression cassette further comprises a second DNA molecule encoding a polyhydroxyalkanoate synthase.
The invention also provides an isolated and purified DNA molecule comprising a first DNA segment encoding a first module and a second DNA segment encoding a second module, wherein the DNA segments together encode a recombinant polyhydroxyalkanoate monomer synthase. Preferably, at least one DNA segment is derived from DNA which is linked to the mitomycin gene cluster of S. lavendulae. Also preferably, no more than one DNA segment is derived from the eryA gene cluster of Saccharopolyspora erythraea. In one embodiment of the invention, the 3xe2x80x2 most DNA segment of the isolated DNA molecule of the invention encodes a thioesterase II. Also provided is an expression cassette comprising a nucleic acid molecule encoding the polyhydroxyalkanoate monomer synthase operably linked to a promoter functional in a host cell.
Yet another embodiment of the invention is a method of providing a polyhydroxyalkanoate monomer. The method comprises introducing into a host cell a DNA molecule comprising a DNA segment encoding a recombinant polyhydroxyalkanoate monomer synthase operably linked to a promoter functional in the host cell. Preferably, the second DNA molecule is derived from DNA which is linked to the mitomycin gene cluster. The recombinant polyhydroxyalkanoate monomer synthase comprises a first module and a second module, wherein at least one DNA segment is derived from DNA which is linked to a mitomycin gene. cluster, e.g., the mitomycin gene cluster of S. lavendulae. The DNA encoding the recombinant polyhydroxyalkanoate monomer synthase is then expressed in the host cell so as to generate a polyhydroxyalkanoate monomer. Optionally, a second DNA molecule may be introduced into the host cell. The second DNA molecule comprises a DNA segment encoding a polyhydroxyalkanoate synthase operably linked to a promoter functional in the host cell. The two DNA molecules are expressed in the host cell so as to generate a polyhydroxyalkanoate polymer.
Another embodiment of the invention is an isolated and purified DNA molecule comprising a first DNA segment encoding a fatty acid synthase and a second DNA segment encoding a module from the DNA which is linked to the mitomycin gene cluster of S. lavendulae. Such a DNA molecule can be employed in a method of providing a polyhydroxyalkanoate monomer. Thus, a DNA molecule comprising a first DNA segment encoding a fatty acid synthase and a second DNA segment encoding a polyketide synthase is introduced into a host cell. The first DNA segment is 5xe2x80x2 to the second DNA segment and the first DNA segment is operably linked to a promoter functional in the host cell. The first DNA segment is linked to the second DNA segment so that the linked DNA segments express a fusion protein. The DNA molecule is expressed in the host cell so as to generate a polyhydroxyalkanoate monomer.
Further provided is a method of providing a polyhydroxyalkanoate monomer synthase. The method comprises introducing an expression cassette comprising a DNA molecule encoding a polyhydroxyalkanoate synthase operably linked to a promoter functional in a host cell. The DNA molecule comprises a first DNA segment encoding a first module and a second DNA segment encoding a second module wherein the DNA segments together encode a polyhydroxyalkanoate monomer synthase. At least one DNA segment is derived from DNA which is linked to the mitomycin gene cluster of S. lavendulae. The DNA molecule is expressed in the host cell. Optionally, the DNA molecule further comprises a DNA segment encoding a polyhydroxyalkanoate synthase. Alternatively, a second, separate DNA molecule encoding a polyhydroxyalkanoate synthase is introduced into the host cell.
Thus, the invention provides an isolated and purified DNA molecule comprising a first DNA segment encoding a first module and a second DNA segment encoding a second module, wherein the DNA segments together encode a recombinant polyhydroxyalkanoate monomer synthase, and wherein at least one DNA segment is derived from the mit/mmc gene cluster of S. lavendulae. Preferably, no more than one DNA segment is derived from the eryA gene cluster of Saccharopolyspora erythraea. In one embodiment of the invention, the 3xe2x80x2 most DNA segment of the isolated DNA molecule of the invention encodes a thioesterase II. Also provided is an expression cassette comprising a nucleic acid molecule encoding the polyhydroxyalkanoate monomer synthase operably linked to a promoter functional in a host cell.
Yet another embodiment of the invention is a method of providing a polyhydroxyalkanoate monomer. The method comprises introducing into a host cell a DNA molecule comprising a DNA segment encoding a recombinant polyhydroxyalkanoate monomer synthase operably linked to a promoter functional in the host cell. The recombinant polyhydroxyalkanoate monomer synthase comprises a first module and a second module, wherein at least one DNA segment is derived from the mit/mmc gene cluster of S. lavendulae. The DNA encoding the recombinant polyhydroxyalkanoate monomer synthase is then expressed in the host cell so as to generate a polyhydroxyalkanoate monomer. Optionally, a a second DNA molecule may be introduced into the host cell. The second DNA molecule comprises a DNA segment encoding a polyhydroxyalkanoate synthase operably linked to a promoter functional in the host cell. The two DNA molecules are expressed in the host cell so as to generate a polyhydroxyalkanoate polymer.
Another embodiment of the invention is an isolated and purified DNA molecule comprising a first DNA segment encoding a fatty acid synthase and a second DNA segment encoding a module from the mit/mmc gene cluster of S. lavendulae. Such a DNA molecule can be employed in a method of providing a polyhydroxyalkanoate monomer. Thus, a DNA molecule comprising a first DNA segment encoding a fatty acid synthase and a second DNA segment encoding a polyketide synthase is introduced into a host cell. The first DNA segment is 5xe2x80x2 to the second DNA segment and the first DNA segment is operably linked to a promoter functional in the host cell. The first DNA segment is linked to the second DNA segment so that the linked DNA segments express a fusion protein. The DNA molecule is expressed in the host cell so as to generate a polyhydroxyalkanoate monomer.
Further provided is a method of providing a polyhydroxyalkanoate monomer synthase. The method comprises introducing an expression cassette comprising a DNA molecule encoding a polyhydroxyalkanoate synthase operably linked to a promoter functional in a host cell. The DNA molecule comprises a first DNA segment encoding a first module and a second DNA segment encoding a second module wherein the DNA segments together encode a polyhydroxyalkanoate monomer synthase. At least one DNA segment is derived from the mit/mmc gene cluster of S. lavendulae. The DNA molecule is expressed in the host cell. Optionally, the DNA molecule further comprises a DNA segment encoding a polyhydroxyalkanoate synthase. Alternatively, a second, separate DNA molecule encoding a polyhydroxyalkanoate synthase is introduced into the host cell.
Also provided is a method for directing the biosynthesis of specific sugar-modified polyketides by genetic manipulation of a polyketide-producing microorganism. The method comprises introducing into a polyketide-producing microorganism a DNA sequence encoding enzymes in sugar biosynthesis, e.g., a DNA sequence comprising SEQ ID NO:75, a variant or fragment thereof, so as to yield a microorganism. that produces specific sugar-modified polyketides. Alternatively, an anti-sense DNA sequence of the invention may be employed. Then the sugar-modified polyketides are isolated from the microorganism. It is preferred that the DNA sequence is modified so as to result in the inactivation of at least one enzymatic activity in sugar biosynthesis or in the attachment of the sugar to a polyketide
Thus, the modules encoded by the nucleic acid segments of the invention may be employed in the methods described hereinabove to prepare polyhydroxyalkanoates of varied chain length or having various side chain substitutions.
The compounds produced by the recombinant host cells of the invention are preferably biologically active agents such as antibiotics, anti-inflammatory agents, anti-cancer agents, antibiotics, immune-enhancers, immunosuppressants, agents to treat asthma, chronic obstructive pulmonary disease as well as other diseases involving respiratory inflammation, or cholesterol-lowering agents; or as crop protection agents (e.g., fungicides or insecticides), as well as biopolymers, e.g., in packaging or biomedical applications, or to engineer PHA monomer synthases. Methods employing these compounds, e.g., to treat a mammal, e.g., a human, bird or fish in need of such therapy, are also envisioned.


L-arginine is produced in high yields by culturing a microorganism of the genus Brevibacterium or the genus Cornyebacterium, which is resistant to a compound of the formula X-guanidine, wherein X is an aliphatic group or derivative thereof. The preferred microorganisms are Brevibacterium flavum FERM BP-2227 and Corynebacterium glutamicum FERM BP-2228.

1. Field of the Invention
The present invention relates to a process for producing L-arginine by fermentation and strains of microorganisms which produce L-arginine in high yield.
2. Discussion of the Background
L-Arginine is an important component of drugs for stimulating liver functions, amino acid infusion, total amino acid preparations, etc. To reduce the production costs of L-arginine, it is important to improve the fermentation yield. In order for microorganisms belonging to the genus Brevibacterium or the genus Corynebacterium to exhibit L-arginine productivity, it is known that a resistance to 2-thiazolealanine (hereafter simply referred to as 2-TA), arginine hydroxamate, etc. should be imparted to the microorganism. It is also known that the production of L-arginine is improved by imparting sulfa agent or argininol resistance, resistance to chemicals such as 8-azaguanine, .alpha.-amino-.beta.-hydroxyvaleric acid, etc., in addition to the chemical resistance described above, and by imparting auxotrophy for amino acids such as L-histidine, L-proline, L-threonine, L-tryptophan, L-lysine, etc.
However, use of the conventional L-arginine-producing strains of microorganisms results in an unsatisfactory yield of L-arginine. Thus, there remains a need for a process for producing L-arginine by fermentation in high yield. There also remains a need for strains of microorganisms which produce L-arginine in high yield by fermentation.

Process for producing l-arginine by fermentation with brevibacterium or corynebacterium


An improved intraurethral bladder control apparatus including housing means having a fluid flow path therethrough, valve means mounted within the fluid valve path and normally bias closed, the valvings responsive to pressure from fluid within the bladder of the patient for opening to allow fluid flow from the bladder through the apparatus of this invention and out of the urethra. A pair of retaining devices are connected to each of the distal and proximal ends of the intraurethral bladder control apparatus. The retainer at the distal end of the apparatus preferably comprises a leaf spring having a plurality of leaves, in the preferred embodiment described herein the plurality comprising four leaves, with a safety device connected to the tip of each leaf to inhibit piercing of the bladder wall when the leaves of the distal end retainer automatically open within the bladder of the patient after placement of the intraurethral bladder control apparatus. The proximal or lower retainer connects to the proximal end of the bladder control apparatus after it is placed in the urethra of the patient, and a portion of the lower retainer abuts the labia.

1. Field of the Invention
The present invention generally relates to the field of medical devices and more particularly to intraurethral bladder control devices, and still more particularly to intraurethral bladder control devices with retaining means.
2. Description of the Prior Art
The use of bladder control devices, often referred to as artificial sphincters, is wide spread in the field of the present invention. The use of such intraurethral valving apparatus and its general knowledge in the field of art can be evidenced by, for example, U.S. Pat. Nos. 4,553,533; 4,679,546; 4,969,474; and 5,123,428.
A continuing problem found in the prior art devices is the safe and secure retention of the bladder control or valving device in the urethra. It is desirable to have the placement of the bladder control apparatus in the urethra be a nonsurgical function, and it is important not only that the device be securely retained once placed in the urethra, but also that a nonsurgical, safe and reasonably simple means of removing the device be present. Various prior art devices have not met all of these criteria.

Intraurethral bladder control device with retainer apparatus


A fitting for a sanitary hose assembly includes a rigid, tubular stem, a cylindrical ferrule, and an annular seal, which coact with the end of the hose to achieve a uniformly leakproof seal for a material flow path through the hose and into the fitting. One end of the ferrule extends over the outer end of the hose, such that the ferrule engages the hose and extends slightly beyond the hose. An inner end of the stem extends through an outer end of the ferrule and into the hose, such that the outer surface of the stem frictionally engages the internal surface of the hose. The stem has an outer end adapted to connect to a similar structure, internal threads which cooperatively engage similar threads on the ferrule, and an outwardly directed land adjacent the threads. The threaded coupling of the stem and the ferrule fixes their relative axial relationship, and also axially compresses the annular seal between. The ferrule is radially crimped to compress the end of the hose between the stem and the ferrule. This combination of components provides a circumferentially uniform and leakproof seal between the hose and the fitting, at relatively low cost.

Various fittings are known in the art for coupling the end of a flexible hose or conduit to a corresponding hose or other device. In certain applications, the hose fittings must meet stringent sanitary requirements. Such applications include dairy processing, food and beverage processing and delivery, pharmaceutical manufacture, and other similar applications. When a flexible hose or conduit must be used in a sanitary environment, it is particularly important that the fittings provide a sealed connection that does not pose a potential for contamination of the materials transported through the hose, for example, by exposure to bacteria or other contaminants. Previous fittings for use in sanitary applications have included permanent-type fittings which are vulcanized or directly molded or crimped to suitable sanitary hoses, or removable-type fittings which are either clamped or threadably secured to sanitary hoses. Conventional vulcanized and crimped fittings generally require precise setup and complicated fixturing to attach the fitting to the hose. The labor intensive setup increases manufacturing cost and cycle times for producing hose sets. Conventional removable fittings with threaded components are often difficult to threadably tighten while compressing the hose between respective components and are typically unable to handle high pressures. Moreover, removable fittings can be taken apart by persons not trained to properly service the fittings, thereby increasing the risk that the fittings will be reassembled incorrectly.
A need therefore exists for a sanitary hose fitting which addresses these and other drawbacks of the prior art.


An improved hammer tool (20) for a boom mountable power hammer (14) for use in demolishing a work surface (12) of concrete and the like. The hammer tool (20) includes an elongated cylindrical body (22) having a first end (24) and a second end (26). The first end, (24) has a shank (28) of a size and shape to be received into the commercial power hammer (14). A hammer head (30) includes a top (32) and a bottom (34). The top (32) connects the hammer head (30) to the second end (26) at a transition section (38). The bottom (34) includes a convex shaped radial striking face (40), which is a portion of a sphere having a center (54) within a portion of the body. In use, the shank (28) and a portion of the body (51) containing center (54) is received and supported within the power hammer (14). The hammer head (30) is raised and lowered to make striking contact with the work surface (12) in a number sufficient to demolish the work surface (12). Resulting stress from the impact, or striking contact, is concentrated at the center (54) within the power hammer supported portion of the hammer tool body (51) in order to reduce stress fracture failure of the hammer tool.

Tools, such as chisels and moil points, have long been used in demolition to break up concrete and the like. Hammer tools have been commonly used in conjunction with boom mountable power hammers for demolishing concrete because the hammer head has a larger striking face that can break up more concrete at each strike, or impact, than a traditional chisel or moil point. FIG. 1 shows the typical prior art hammer tool, or bit, 2 having an elongated body 4 with a shank 6 at one end and a hammer head 8 at the other end of the body 4. The hammer head 8 has a large, flat, circular striking face 10 in which to break up a work surface 12, such as concrete and the like.
In use, the shank 6 of hammer tool 2 is received into a power hammer 14, (shown in phantom). Much of the body 4, as well as the hammer head 8, extends externally and downwardly of power hammer 14. The power hammer 14 is raised and lowered over the work surface 12, in order to bring hammer head 8 into striking contact with work surface 12, typically, in a force range of up to 15,000 ft.-lbs class.
When hammer head 8 makes striking contact with the work surface, the hammer head is subjected to very high stress from the impact. The flat striking face of the hammer head directs all of the resulting stress upward at the time of impact. Stress lines are shown in dashes on FIG. 1, which are generally perpendicular to that of the striking face 10. The resulting stress is born by the hammer head 8, and is not concentrated within the power hammer supported portion of hammer tool 2. Hence, these type hammer tools can sustain hairline fractures, which can quickly lead to catastrophic failure of hammer head 8, thereby rendering hammer tool 2 useless.
These type of hammer tools are expensive, typically costing several hundred or even thousands of dollars. These type of hammer tools are heavy, as well, weighing anywhere from 100 to 1500 lbs. If catastrophic failure occurs, costly delays may ensue as replacement hammer tools may not be readily available, especially if the demolition site is remote. Additionally, injury to workers or property, could result as a consequence of catastrophic failure.
Moreover, although not generally intended, the hammer tool striking face may not always strike the work surface in a perpendicular (non offset) manner, such as shown in FIG. 2. This situation may occur because the work surface is not perfectly horizontal, or it may be attributed to operator error. Stress in this circumstance is concentrated at one end of the hammer head and adjacent portion of the body, shown at "16". Early catastrophic failure of the hammer tool is likely to occur at the unsupported area of the stress concentration.

Hammer tool for boom mountable power hammer


A rotation control method of a synchronous motor, the motor comprising: a stator having AC windings thereround; and a rotor, being mounted within said stator, rotatably, wherein on an each surface, opposing to the rotor, of poles building up the stator, are formed plural numbers of teeth portions, and on a surface of the rotor, being made of permanent magnet, opposing to the poles of the stator, are also formed plural numbers of teeth portions, with a width being nearly equal to that of the teeth portion in a circumference direction thereof, and further AC voltages having a predetermined voltage-frequency characteristic is supplied to AC windings wound around the poles of the stator, and the AC voltages supplied from the inverter is so determined in the voltage-frequency characteristic thereof, at least within a part of frequency band equal or less than a predetermined rated frequency, a pull-out torque of the synchronous motor is equal to or greater that a rated pull-out torque at the predetermined rated frequency, thereby providing a synchronous motor and also an inverter to be used for such the synchronous motor, but hardly causing the step-out phenomenon in the operating condition when accelerating and decelerating the synchronous motor.

The present invention relates to a synchronous motor having a rotor, which is rotatably mounted within a stator having AC (alternating current) windings wound therearound, and a rotation control method thereof, as well as, an inverter for use of such the synchronous motor, and in particular, it relates to a synchronous motor and a rotation control method, in which plural numbers of teeth portions are formed, not only upon a surfaces of each of poles building up said stator, but also upon a surface of said rotor opposing to those poles, respectively, and thereby enabling to obtain a desired characteristic through applying AC voltage thereto from an inverter, as well as, the inverter for use in such the synchronous motor.
Conventionally, when driving a pump and/or a fan, rotationally, as a load thereon, as was already known in the following Patent Document 1, etc., for example, a cryopump driving apparatus is widely used, which is built up with a driving apparatus having a synchronous motor therein, for rotationally driving the load, such as, a refrigerator of a cryopump, etc. And, with such the conventional art, for driving the synchronous motor mentioned above with using a commercial electric power source of frequency 50 Hz, it was already known to conduct the frequency conversion on the frequency of the electric power with using a frequency converter (i.e., an inverter), thereby to drive the synchronous motor with a desired frequency.
On the other hand, as a synchronous motor for general uses or purposes, i.e., being a kind of an AC electric machine, as well as, a rotor having windings wound thereround or that being made of permanent magnet, in the structure thereof, there was already known a synchronous motor, of so-called a type of multi-pole structure, adopting a rotor of applying a permanent magnet(s) in a part thereof, upon the surface of which are formed plural numbers of gutters; i.e., teeth portions, in a direction of the rotating axis thereof. Though such the structure of the rotor, having the teeth portions formed thereround, was also applied, widely, in such as, so-called a stepping motor; however, due to discovery of magnets of the rare-earth elements (for example, neodymium, samarium, cobalt, etc.) having high antimagnetic force, in recent years, it is possible for the motor to obtain a higher torque therefrom, in spite of the same structure or sizes thereof, and also to manufacture it with relatively a large amount thereof, but cheaply; therefore, being widely applied therein.
In addition thereto, for an induction electric machine or motor, there are also known various apparatuses, such as, a voltage controller apparatus for an inverter, in which the inverter built up with a transistor bridge or the like is controlled, so as to obtain an improvement on the characteristics thereof when the motor rotates at a low speed, for example, in the Patent Document 2 which will be listed up below, etc. Namely, with such the conventional technology as was mentioned above, within the control method of maintaining V/F ratio (=φ) constant for satisfying a rated load, in general, and in particular for dissolving shortage of the torque generated from the motor when it rotates at a low speed, the V/F ratio is increased when a frequency is lowered, normally, and at the same time, adjustment is made on terminal voltage of the induction motor in relation with torque of the load, fitting to the characteristic of the load, thereby providing a voltage controller apparatus for the inverter fitting to the load characteristics.
Patent Document 1: Japanese Utility-Model Publication No. Hei 1-14775 (1989); and
Patent Document 2: Japanese Patent Laying-Open No. Sho 57-180395 (1982).
However, in a case when controlling the voltage to be supplied into the induction motor and/or the general-use synchronous motor with using a normal inverter, as was mentioned in the above, however in general, the control method of V/F ratio (=φ) constant is mainly used for the purpose of satisfying the rated load. However, in particular, as was mentioned above, in the case when controlling AC supply voltages for driving the synchronous motor having such the structure, i.e., while forming the plural numbers of teeth portions on the surfaces of the stator poles in the direction of rotation axis thereof, adopting the rotor made of using the permanent magnet in a part thereof, which also forms the plural numbers of teeth portions on the surface thereof in the direction of rotation axis thereof, it is not always possible to obtain sufficient characteristics or performances therefrom. However, this can be considered resulting from the fact that, in particular, the above-mentioned voltage control of applying the inverter therein is mainly achieved for controlling the supply voltages to the induction motor and the synchronous motor, and therefore, it is not always fitting to such the structure of the motor mentioned above, too.

Synchronous motor and a rotation control method thereof, as well as, an inverter for use of the synchronous motor

Hitachi Industrial Equipment Systems Co., Ltd.