The present invention provides a method of effectively modifying starch so as to have an inhibitory effect on swelling and disintegration equivalent to that of chemically-linked starch, without using chemicals or a large amount of water.

In the manufacture of food products, filling materials such as custard creams containing wheat flour and starch as the main ingredients are used in breads and confectionaries. When heated in the presence of a large amount of water, starch is swollen by the absorption of the surrounding water at a certain temperature range, thereby increasing viscosity. This phenomenon is called the "gelatinization" of starch. Because of this phenomenon, starch is widely used as a thickener or shape retainer for processed foods. However, natural, unmodified starch undergoes a phenomenon known as "breakdown"; that is, starch granules are disintegrated during gelatinization and subsequent stirring, and the original viscosity is barely maintained. This "breakdown" prominently occurs when the shear force during stirring is high or when the pH of the system is low, and therefore may become a problem during the production of processed food products.
For foods such as custard creams and jams, starch undergoing breakdown is unsuitable, and starch in which the viscosity reduction due to the disintegration of starch granules is suppressed is conventionally used. As such starches, distarch adipates and distarch phosphate etc., (referred to as chemically modified starch or processed starch) obtained by cross-linking glucose chains of starch through chemical reaction, are used.
In order to suppress the breakdown of starch, various attempts have been made to modify starch in combination with polysaccharide thickeners. Patent Document 1 proposes modifying starch by mixing xanthan gum with starch in powder form, adding thereto water to control the moisture, and heating the mixture at 100 to 200° C. for 30 minutes to 5 hours under dry conditions. Patent Document 2 discloses a method of producing modified starch, comprising mixing starch with raw soybean powder at a ratio of 0.1 to 20% with respect to the starch, and heating and aging the mixture at an initial moisture of 8% or higher. Additionally, the following methods have also been proposed: a method of producing moist-heat-treated starch, in which starch is put in a sealable container that is provided with both a vacuum line and a pressurized steam line and that is resistant to internal and external pressures, the pressure in the container is reduced, the starch is pressurized and heated by feeding steam to the container, and optionally this operation is repeated, thereby heating the starch for a predetermined time, after which the starch is cooled (Patent Document 3); a method of suppressing thermal swelling of starch by incorporating 0.1 to 10 mass % of organic acid salt in starch, followed by heating (Patent Document 4); and a method of producing denatured starch, comprising dispersing starch in an aqueous polar solvent containing 5 to 20 mass % of polar solvent and 15 to 30 mass % of water both based on the starch, and heating the dispersion at or above a gelatinization-starting temperature, but below 100° C. (Patent Document 5).
Patent Document 1: Japanese Unexamined Patent Publication No. 2005-54028
Patent Document 2: Japanese Unexamined Patent Publication No. 1981-78572
Patent Document 3: Japanese Unexamined Patent Publication No. 1992-130102
Patent Document 4: Japanese Unexamined Patent Publication No. 2005-171112
Patent Document 5: Japanese Unexamined Patent Publication No. 2006-131772

Method for modifying starch and method for producing starch blended preparation

Abstract: The method of modifying starch includes subjecting a powdery mixture containing starch and water-soluble hemicellulose at a ratio of 99.5:0.5 to 80:20 (weight ratio) to moist-heat treatment at 100 to 200° C.


Described is a method for operating a converter for a system for generating electrical energy. In an embodiment of the method, the output voltage of the converter is converted to a d, q coordinate system, wherein the d, q coordinate system is assigned to the frequency of the voltage for the energy supply grid. A desired value is furthermore specified in the d, q coordinate system, several momentary or future values are determined from the output voltage in the d, q coordinate system for different switch positions of the converter, deviations between the desired value and the momentary or future values are determined in the d, q coordinate system, and the converter is switched to one of the switch positions in dependence on these deviations.

A known system is provided with a generator that is connected to a converter which, in turn, is connected to an energy supply grid. The frequency of the voltage generated by the generator is variable. A plurality of different switch positions can be realized with the converter.
This system can be used to connect an energy producer, for example a wind electrical energy plant, to a public three-phase grid. The wind electrical energy plant operates the generator with a variable speed. The frequency of the voltage generated by the generator is thus also variable and must be adapted to the substantially constant frequency of the three-phase grid, achievable with the aid of the converter. Numerous controls and/or adjustments are known for these converters.

Method for operating a converter in a system for generating electrical energy

GE ENERGY POWER CONVERSION TECHNOLOGY LIMITED


The present invention relates to a pipe heater encircled conduit device (1), in which a heating element (111) wrapped with a filament (112) having high resistance is provided and a hollow quartz inner tube (113) is inserted at the outside of said heating element (113) to form a pipe heater (11), both ends of the heating element (111) being connected with an electrode pin (114) respectively. A hollow quartz outer tube (123) is inserted at the outside of the pipe heater (11), which has an inlet (121) and an outlet (122) on the tube wall. A heat transfer space (A) is thus formed between the inner quartz tube (113) and the outer quartz tube (123), and insulation members (124) are combined with the respective opening end of both tubes. By the arrangement of the inner and outer quartz tubes. (113), (123), the heat energy generated by the pipe heater (11) formed by the heating element (111) and the hollow inner quartz tube (113) can be transferred to the medium which is introduced from the inlet (121) and exhausted from the outlet (122). Thus, the medium can be heated by the heat energy generated by the heating element (111) itself by both actions of heat conduction and heat radiation.

1. Field of the Invention
The present invention relates to a pipe heater encircled conduit device in which the heat energy can be transferred through a space between a hollow inner quartz tube and a hollow outer quartz tube by both actions of heat conduction and radiation.
2. Brief Description of the Prior Art
As shown in FIG. 10, conventional pipe heater (3) generally has a hollow metal pipe (31) in which a heating element (32) is provided, and electrode pins (33) for connection with outside power source are connected to both ends of the heating element (32). Kaolinite (34) for insulation purpose is filled within the hollow metal pipe (31). Then, the hollow metal pipe (31) is rolled so as to make the filled kaolinite become more compact. Both ends of the hollow metal pipe (31) are sealed by the resin glue (35) so that the interior of the hollow metal pipe (31) is in sealed state. However, the pipe heater (3) is placed within the barrel having heat insulation that is used to hold water. The hollow metal pipe (31) in long term contact with water causes oxidization easily which results in gradual corrosion. Serious corrosion often leads to the rupture of the hollow metal pipe (31), in turn gives rise to current leakage problem. Furthermore, large amount of mineral materials contained in the water also cause impurities or scale formation on the pipe. The scale formation on the pipe will bring about resistance to the transfer of the heat generated from the pipe heater (3), i.e, deterioration of heat transfer efficiency.


A street marking strip device formed of a resilient and flexible strip material includes a traffic marking on a visible side thereof and a street engaging underside having longitudinally extending clearances and cavities separated by longitudinally extending contact edge zones for releasably engaging a street surface. The strip material optionally may include longitudinally extending reinforcement elements in the form of strand or sheet material and may include prestressing elements for giving the strip material an overall concave shape when it is in its unloaded condition. When the prestressed strip material engages a street surface, a clawing action results as the strip material is flattened against the street surface. The strip material may be readily released from the street surface and reused again. The strip material includes tapered flanks to ensure smooth traversal by automobiles.

The invention concerns a street marking-device consisting of a rubber or flexible-plastic marker strip with traffic marking and which in use is self-secured to the street surface, with the bond between the strip and the street surface being disengageable and renewable.
Such a marking device already is generally known from German patent No. 39 05 597 C2. When used to mark street surfaces, this known marking device is wound off a roll onto the street pavement, with the adhesion between the marking device and the street pavement being assured solely by the weight of the marking device. No further adhesion or bonding exists between the marking device and the street pavement. To assure good positional stability during use, the known marking device has a high specific gravity and when not loaded by traffic is prestressed transversely about its longitudinal axis so as to curve concavely relative to the street pavement.


An improved compensation piston arrangement for use with a dual circuit master cylinder having a single service piston for simultaneously pressurizing a first fluid chamber and a second fluid chamber, wherein the compensation piston arrangement provides for pressure balancing between the first fluid chamber and the second fluid chamber to compensate for minor normal differences between the first and second fluid chamber. The compensation piston arrangement includes a movable compensation piston slidably disposed within a bore of a compensation housing, wherein the housing defines a pair of end stops positioned on opposing sides of the compensation piston. The bore is in fluid communication with the fluid chambers such that the pressure within the first fluid chamber acts on a first side of the compensation piston, and the pressure within the second fluid chamber acts on a second end of the compensation piston which is opposite the first end. The compensation housing can be incorporated within the service piston or can be remotely located from the master cylinder.

This invention relates in general to vehicle hydraulic brake systems and in particular to a dual circuit master cylinder adapted for use in such a vehicle hydraulic brake systems.
Most vehicles are equipped with a brake system for retarding or stopping movement of the vehicle in a controlled manner. A typical brake system for an automatic or light truck includes a disc brake assembly for each of the front wheel of the vehicle, and either a disc or drum brake assembly for each of the rear wheels of the vehicle. The brake assemblies are actuated by hydraulic pressure generated when an operator of the vehicle depresses a brake pedal. A typical hydraulic brake system includes a first hydraulic circuit and a second hydraulic circuit. The first and second circuits can be connected to the wheel brakes by various configurations, such as a diagonally split arrangement or a vertically split arrangement. In a diagonally split arrangement, the first circuit is connected to one of the front wheel brakes and to one of the rear wheel brakes on the opposite side from the connected front wheel brake. The second circuit is then connected to the other one of the front wheel brakes and the other one of the rear wheel brakes on the opposite side of the connected front wheel brake. In a vertically split arrangement, the first circuit is connected to the front wheel brakes, and the second circuit is connected to the rear wheel brakes. The use of two brake circuits helps to maintain a source for braking of the vehicle in case of failure of one of the brake circuits.
A dual circuit or tandem master cylinder is used to supply pressurized fluid to the first and second brake circuits. A conventional tandem master cylinder includes a pair of service pistons which are operatively connected to the brake pedal operated by the vehicle operator. Actuation of the brake pedal causes movement of the pistons which energize or pressurize first and second fluid chambers in the master cylinder which are operatively connected in fluid communication with the first and second brake circuits, respectively. However, the use of a master cylinder having two pistons can have drawbacks should one of the two hydraulic brake circuits fail. For example, upon failure of one of the two brake circuits, the stroke of the associated piston of the master cylinder can increase in length due to abnormal movement of the associated piston, thereby causing a relatively large brake pedal drop.
It is known to use a master cylinder having a single service piston. In a master cylinder having a single piston, the movement of the piston simultaneously energizes the first and second fluid chambers. However, the respective pressures within the first and second hydraulic circuits can fluctuate with respect to each other because of different volumetric requirements of the associated hydraulic circuits due to various factors. For example, the fluctuations can result from different manufacturing tolerances, uneven brake pad or lining wear, or differences in the various components in the disc and drum hydraulic brake circuits.
It would be desirable to provide a compensation device for a master cylinder having a single service piston for use in a hydraulic brake circuit which is simple, inexpensive to manufacture, and does not cause a relatively large pedal drop in case of failure of one of the two hydraulic circuits.

Master cylinder having a single service piston with compensation and damping sections


This invention relates to a process for the co-encapsulation of biocidally active ingredients in a clay mineral, the process comprising the step of bringing the clay mineral into contact with a biocidally active nitrogen compound that contains at least one hydrocarbon group with 6 to 20 carbon atoms, and at the same time or subsequently with at least one biocidally active compound selected from the group consisting of 2-n-octyl-4-isothiazoline-3-one, 3-iodopropenylbutyl-carbamate and tetrahis(hydroxymethyl)phosphonium sulfate. And the use of such encapsulated product in water based paints, coatings and varnishes.

The process of production of clay minerals having a lipophilic characteristic ("organoclays") using ammonium quaternary salts to give to clay minerals said lipophilic characteristic is known. Clay minerals, especially smectite, are a class of minerals that contain in their structural formula dioctahedral aluminous species which can be represented by the formula[(Al(2−y)Mgy)(Si(4−x)Alx)O10(OH)2][M(x+y)]nH2Owherein:    x is the amount of aluminum atoms exchangeable from octahedral sheet, and    y is the amount of silicon atoms exchangeable from tetrahedral sheet, and    M(x+y) are monovalent cations present in the clay structure to compensate the resultant charge after the exchange of aluminum and silicon have occurred into the octahedral and tetrahedral sheets, respectively.
Regarding the total amount of cation exchangeable capacity, (x+y) comprises the range 0.2≦(x+y)≦0.6. This range represents the minimum and maximum milliequivalents of cation exchangeable in 100 g of clay mineral.
U.S. Pat. No. 2,531,427 discloses that if M(x+y) is exchanged by an ammonium quaternary salt two different effects are observed in the clay mineral. The replacement of the cation by the ammonium quaternary salt causes an enlargement of the distance between layers of the clay mineral, and the clay mineral surface becomes hydrophobic because of the presence of the alkyl groups introduced by the ammonium quaternary salt. The objective of that invention was to provide a modification of the clay mineral by replacing the interlayer cation by amines in order to give to the clay mineral surface a substantial gelling characteristic which swelled when dispersed in an organic liquid.
Further state of the art is summarized as follows.
U.S. Pat. No. 3,467,208 discloses the application of bentonite treated by long-chain amines in order to give good thixotropy for an oil based drilling mud and to avoid the fluid loss during the well drilling process.
U.S. Pat. No. 3,831,678 discloses the use of a clay which has been organically functionalized by dimethyltallow hydrogenated ammonium salts as viscosifier in oil based drilling fluids.
U.S. Pat. No. 4,752,342 teaches a process for the replacement of sodium by an ammonium quaternary salt in a clay mineral.
The state of the art presented above does not present any disclosure about encapsulation or co-encapsulation of biocidally active ingredients interlayer of the clay minerals. It discloses the preparation of organophilic clays with several types of amines and ammonium quaternary salts.
U.S. Pat. No. 5,164,096 discloses the use of biocide contained within the core of the microcapsules made of a gum gelatin membrane. These microcapsules are used to treat a water system by controlled release of the biocide actives.
WO-A-93/02668 discloses the microencapsulation of at least one active ingredient, contained in an hydrophilic internal core, coated by a coat of copolymer of ethylene and vinyl acetate (EVA) or a copolymer of vinylidene chloride and vinyl chloride and other types of polymers.
U.S. Pat. No. 6,165,485 discloses that a bentonite based organoclay, when mixed with a biocidal quaternary amine containing a benzyl molecule within its structure, acts as a reasonably effective biocide.
U.S. Pat. No. 6,521,678 describes a method for preparing organoclays with a substantially monomolecular layer of water soluble polymer to the clay; applying a surfactant to the clay to modify the hydrophilic/hydrophobic balance of surfaces of the clay and separate out the organoclay from the water.
U.S. Pat. No. 7,429,392 discloses the use of biocides bonded to solid resins particles in order to confer antimicrobial protection to highly alkaline coating films, e.g. paints, leading to higher stability in the pH of the paint and delayed release of the biocide.
It has been observed that there are biocidally active ingredients that cannot be encapsulated into organophilic clay using the encapsulation modifiers of the state of the art. The problem of the instant invention was to find an encapsulation modifier that allows such biocidally active ingredients to be encapsulated in a clay mineral.
It has been found that the use of clay mineral functionalized by hydrocarbon-substituted nitrogen compounds allows co-encapsulation of several types of biocidally active ingredients which otherwise can not be inserted into the interlayer of the clay mineral without the presence of the hydrocarbon-substituted nitrogen compounds.

Process for the co-encapsulation of biocidally active compounds in clay minerals functionalized by nitrogen compounds


A battery pack includes a case having an upper case part and a lower case part. The battery pack further includes a battery cell accommodated inside the case, and a plurality of electrode terminals electrically connected to the battery cell. The upper case part has an opening which is arranged at a position corresponding to a position of the plurality of electrode terminals and exposes the plurality of electrode terminals. The batter pack additionally includes a suppressing member that suppresses foreign matter from entering inside the case via the opening.

For example, JP-2006-302759-A discloses a battery pack used in a power tool. In the battery pack, a battery case is L-shaped in a side view, and an electrode terminal to be connected to an electrode terminal of a power tool body is disposed at an upper end of the battery case.
In the battery pack, when the battery pack detached from the power tool is placed in a sideways failing-down state, in case that the shock is applied to the battery pack, if a portion that has received its shock is in the vicinity of the electrode terminal, the shock is readily given onto the electrode terminal, with the result that the electrode terminal can be damaged or broken.

Battery pack and power tool provided with the same


A casket latch assembly has a strike plate attached to a casket lid. The strike plate has a strike plate edge and a strike plate surface. A flexible latch arm is attached to a casket lower shell. The latch arm has a latch edge for engaging the strike plate surface of the strike plate to hold the lid in a closed position. A release mechanism for disengaging the latch edge from the strike plate surface to allow the closed lid to open.

Caskets are used for the interment of the bodies of deceased persons. Before interment, the body of the deceased is typically displayed for the benefit of loved ones at a funeral. When the body is displayed, the head portion of the casket lid and/or the leg portion of the casket lid is opened and locked in a raised position. When the viewing is completed, the lid portion(s) are returned to a closed position.
In the closed position, the lid portions are typically firmly held against the lower casket shell by one or more latch or locking mechanisms. The latch or locking mechanism should be economical and easy to use. Further, the latch mechanism should provide a positive indication that the lid has been locked in place. The invention provides such a casket latch.


The present invention mainly discloses low power non-isolated driver that can be used for LED lighting and other non-isolated power supply appliance, in which the input side is connected to an AC or DC input, a PWM control circuit is connected to the buck converter switch, a capacitor filters the output voltage ripple and an output voltage/current control circuit provides feedback signal to the PWM control circuit. The present invention has such features of less component number, low total cost, high reliability, and better line/load regulation.

LED lighting market is growing very fast and becoming more and more important. For the AC input source, most LED drivers adopt switching mode power supply (SMPS) based on flyback topology. The flyback SMPS circuit usually consists of AC input, PWM control circuit, transformer and constant voltage/current control circuit, wherein the output voltage/current control circuit are coupled through an optical coupling element to the primary side PWM control circuit. The PWM control circuit adjusts the switching duty cycle when line voltage or load is changed, so constant output current or voltage can be realized.
However, the cost of flyback SMPS circuit is relatively high and the total system size is big. For home appliance, it is ideal that the LED lighting driver is compact and can be placed in the lamp holder like CFL (compact fluorescent lamp). Thus the whole LED lighting system's installation will be easy. Also for compact LED lighting driver, isolating may not be needed if plastic lamp holder is used.
Therefore, it is necessary to provide new cost down solutions with less component count, small print circuit board size and better price/performance ratio.


The present invention relates to the field of plant molecular biology, more particularly Jatropha microsomal co6 oleate desaturases. The present invention also relates to Jatropha plants or plants of other oil crops having seeds with altered ratios of monosaturated and polyunsaturated fats. In particular, the present invention relates to Jatropha plants or plants of other oil crops where the plants exhibit elevated levels of oleic acid.

The present invention relates to the field of plant molecular biology, more particularly Jatropha microsomal ω6 oleate desaturases. The present invention also relates to Jatropha plants or plants of other oil crops having seeds with altered ratios of monosaturated and polyunsaturated fats. In particular, the present invention relates to Jatropha plants or plants of other oil crops where the plants exhibit elevated levels of oleic acid.
The publications and other materials used herein to illuminate the background of the invention, and in particular, cases to provide additional details respecting the practice, are incorporated by reference, and for convenience are referenced in the following text by author and date and are listed alphabetically by author in the appended bibliography.
Plant oils have many kinds of diverse applications. Novel vegetable oil compositions and improved approaches to obtain oil compositions, from biosynthetic or natural plant sources, are needed. Depending upon the intended oil use, various different fatty acid compositions are desired. Plants, especially species which synthesize large amounts of oils in seeds, are an important source of oils both for edible and industrial uses (Lu et al.; Durrett et al., 2008).
One major usage for plant oil is for food. Plant oils are mostly composed of five common fatty acids, namely palmitic acid (16:0), stearic acid (18:0), oleic acid (18:1), linoleic acid (18:2) and linolenic acid (18:3) (Durrett et al., 2008). Oleic acid is a monounsaturated omega-9 and 18 carbon fatty acid found in various vegetable oils. It is considered one of the healthier sources of oil and fat in food resources for human and animal. Diets in which oil consumption are high in oleic acid have been proven to downregulate overall levels of chronic human diseases such as cholesterol, arteriosclerosis and cardiovascular disease. Specifically, oleic acid has been shown to raise levels of high-density lipoproteins (HDLs) known as "good cholesterol", while lowering low-density lipoproteins (LDLs) also known as the "bad" cholesterol. Thus, the development of new and inexpensive sources of foods comprising healthier forms of fatty acid is desirable.
One emerging purpose for oil is to serve as feedstock of renewable bioenergy in the form of biodiesel. The demand for use biodiesel, mainly comes from vegetable oil, has soared along with government subsidies and mandates for the alternative fuel. Because there are various fatty acid composition of each types, the fuel properties of biodiesel derived from a mixture of fatty acids are dependent on that composition. Compared with conventional diesel, there are some negative factors of fatty acid profile should be optimized by traditional breeding or genetic engineering to optimize biodiesel fuel characteristics. Various studies suggest that biodiesel with high levels of methyl oleate will have excellent, characteristics with regard to ignition quality, NOx emissions and fuel stability. For example, while unsaturation tends to reduce the cetane number of biodiesel, that of methyl oleate is higher than the minimal biodiesel standard. Additionally, it has been estimated that biodiesel fuels with an average of 1.5 double bonds per molecule will emit an equivalent amount of NOx compared with conventional diesel, thus a fuel high in oleates should not result in higher NOx emissions. Finally, given that polyunsaturated fatty acids have a major effect on the auto-oxidation of biodiesel, high oleic acid with reduced polyunsaturated fatty acid content will improve the stability of the fuel (Durrett et al., 2008).
Soybean lines with high levels of oleic acid and low levels of saturated and polyunsaturated fatty acids have been developed using a transgenic strategy that results in down-regulation of one single gene fatty acid desaturase 2 (FAD2). Consistent with predictions, biodiesel synthesized from these high-oleic soybeans demonstrated improved fuel characteristics with regard to cold-temperature flow properties and NOx emissions (Tat et al., 2007; Graef et al., 2009).
During the last several years, many countries have begun to target biofuel research as a national priority and implement compulsory blending of fossil fuel with biofuel. The increasing demand for biofuel, however, is exerting more pressure on food production because of the competition between fuel crops and food crops for arable land. One way to ease this competition is to use marginal land for bio-energy production (Carroll and Somerville, 2008).
Jatropha curcas, a small woody plant belonging to Euphorbiaceae, is a non-food crop mainly grown in the tropical and subtropical regions. This plant possesses several properties rendering it suitable for biodiesel production, such as its rapid growth, ease of propagation, short gestation period, low seed cost, high oil content, wide adaptability, and drought tolerance (Jones N, 1991; Fairless, 2007). Furthermore, Jatropha may yield more than four times as much fuel per hectare as soybean, and more than ten times that of maize (corn) (http://en.wikipedia.org/wiki/Jatropha_oil). Especially important is that Jatropha can thrive on degraded soil (Fairless, 2007) making it an attractive crop for biodiesel feedstock since it can be planted on a large-scale on marginal land unsuitable for food crops.
Plants synthesize fatty acids via a common metabolic pathway known as the fatty acid synthase (FAS) pathway. Beta-ketoacyl-ACP (acyl carrier protein moiety) synthases are important rate-limiting enzymes in the FAS of plant cells and exist in several versions. Beta-ketoacyl-ACP synthase I catalyzes chain elongation to palmitoyl-ACP (C16:0), whereas Beta-ketoacyl-ACP synthase II catalyzes chain elongation to stearoyl-ACP (C18:0). Beta-ketoacyl-ACP synthase IV is a variant of Beta-ketoacyl-ACP synthase II, and can also catalyze chain elongation to 18:0-ACP. In soybeans, the major products of FAS are 16:0-ACP and 18:0-ACP. The desaturation of 18:0-ACP to form 18:1-ACP is catalyzed by a plastid-localized soluble delta-9 desaturase (also referred to as "stearoyl-ACP desaturase").
The products of the plastidial FAS and delta-9 desaturase, 16:0-ACP, 18:0-ACP, and 18:1-ACP, are hydrolyzed by specific thioesterases. Plant thioesterases can be classified into two gene families based on sequence homology and substrate preference. The first family, FATA, includes long chain acyl-ACP thioesterases having activity primarily on 18:1-ACP. Enzymes of the second family, FATB, commonly utilize 16:0-ACP (palmitoyl-ACP), 18:0-ACP (stearoyl-ACP), and 18:1-ACP (oleoyl-ACP). Such thioesterases have an important role in determining chain length during de novo fatty acid biosynthesis in plants, and thus these enzymes are useful in the provision of various modifications of fatty acyl compositions, particularly with respect to the relative proportions of various fatty acyl groups that are present in seed storage oils.
The products of the FATA and FATB reactions, the free fatty acids, leave the plastids and are converted to their respective acyl-CoA esters. Acyl-CoAs are substrates for the lipid-biosynthesis pathway (Kennedy Pathway), which is located in the endoplasmic reticulum (ER). This pathway is responsible for membrane lipid formation as well as the biosynthesis of triacylglycerols, which constitute the seed oil. In the ER there are additional membrane-bound desaturases, which can further desaturate 18:1 to polyunsaturated fatty acids.
Various technologies for generating mid to high oleic acid levels in soybean plants are known. For example, U.S. Patent Publication No. 2007/0214516 discloses a method for obtaining soybean plants that have moderately increased levels of oleic acid.

TEMASEK LIFE SCIENCES LABORATORY LIMITED


The invention relates to a compensation circuit for driver circuits having a current reference source which generates at least one reference signal which is modulated with respect to an input signal, having a current-comparison source which generates at least one comparison signal which is modulated with respect to the input signal, the modulated comparison signals having an inverse characteristic to that of the modulated reference signals in respect of the parameters to be modulated, having a comparison unit to which the modulated reference signals and the modulated comparison signals are fed and which generates from a comparison of these modulated modulating signals at least one digital output signal which can be fed to driver circuits connected downstream.

The invention relates to a compensation circuit for driver circuits.
The signals of input/output pad cells (I/O pad cell) of an integrated circuit must have a defined, minimum signal edge steepness of the signals passing via the I/O pad cells depending on the specification and/or depending on the desired requirement. Owing to temperature, voltage and process fluctuations, it is, however, possible for more or less pronounced diffusions of the signal edge steepness to occur. Owing to these, driver circuits for I/O pad cells must be configured in such a way that minimum signal edge steepness can be guaranteed even in what is referred to as the xe2x80x9cworst casexe2x80x9d i.e. at a very high temperature and with the low supply voltage and xe2x80x9cslowxe2x80x9d process parameters.
Hitherto, driver circuits have been used for this which simultaneously fulfill all the abovementioned requirements. The resulting driver circuits are, however, overdimensioned for most temperature, voltage and process values, giving rise to an increased xe2x80x9cground supply bouncexe2x80x9d which can negatively influence the operational capability of the entire integrated circuit and in the worst case lead to malfunctions.
The present invention is therefore based on the object of disclosing a compensation circuit for driver circuits which ensure a defined minimum signal edge steepness of a signal in the case of I/O pad cells even under unfavorable conditions.
This object is achieved according to the invention by means of a compensation circuit for driver circuits having the features of patent claim 1.
Advantageous refinements and developments of the invention are the subject matter of the subclaims.
According to the invention, a digitally controlled compensation circuit or compensation unit (DCCU) is provided for this and is connected upstream of the driver circuit. This compensation unit according to the invention is composed essentially of four circuit parts: a current reference source, a current-comparison source, a comparator stage and a logic stage. The comparison unit is used to compensate temperature, voltage and process fluctuations in the driver circuit for the I/O pad cells. In this way, the signal edge steepness of the signals passing via these I/O pad cells is monitored and kept approximately constant over the abovementioned fluctuations. Furthermore, this can also permit a considerably reduced xe2x80x9cground supply bouncexe2x80x9d to be achieved.

Compensation circuit for driver circuits


Systems and methods for identifying defective pixels and adjusting an input to control display of the defective pixels may improve the quality of the image viewed on a flat panel display including one or more defective pixels. The screen position of each defective pixel is identified and stored. Adjustment information is also stored for each defective pixel. The adjustment information is used to modify a stored color value for each defective pixel or to disable one or more color components of each defective pixel prior to displaying an image on a flat panel display device including the defective pixels.

1. Field of the Invention
Embodiments of the present invention generally relate to identifying defective pixels in a flat panel display and adjusting the inputs for those pixels.
2. Description of the Related Art
Conventional flat panel displays typically suffer from pixels that are defective, either failing completely, e.g., displaying black or white, or having one or more color components (red, green, or blue) that fail. Because the failures are typically the result of manufacturing defects, they are permanent and cause visual artifacts in any image displayed on the defective flat panel display.
Accordingly, there is a desire to control the display of defective pixels for flat panel displays to improve the quality an image displayed on each defective flat panel display.

Defective pixel management for flat panel displays


The present invention provides a robust and efficient process for reducing the cloud point of biodiesel fuel in which clathrates are formed from saturated fatty acid components as solvent is evaporated from a mixture of urea, methanol and fatty acid esters. The process speed can be fast, and is governed by the speed with which urea can be brought into clathrate forming contact with the fatty acid esters in the first instance, and then by the speed that solvent can be evaporated. Advantageously, substantially all of the solvent can be evaporated as pure solvent, which enhances process efficiencies and reduces cost. Additionally, substantially all of the urea can be used to form clathrates, further maximizing process efficiency.

The present invention generally relates to fatty acid esters, and more particularly to a method for lowering cloud point of the fatty acid esters. A multitude of energy crises have been caused by disruption of fossil fuel supplies, coupled with significantly increased demand for fossil fuels by industrialized nations. In the past few decades, these crises have encouraged the development of alternative fuels. Additionally, since there are finite reserves of crude oil from which petroleum-based fuels are derived, there has also been a trend toward developing renewable fuels, such as biodiesel, which is derived from renewable sources.
Soy methyl ester (SME) or methyl soyate, the chemical description of which is provided below, is a common organic acid ester precursor for producing biodiesel. Organic acids, as the name indicates, are organic compounds with acid-like properties. One common group of organic acids are carboxylic acids, which have a "—COOH tail." Esters constitute a class of organic acid compounds where at least one —OH member is replaced by an alkoxy group (—O—CnH2n+1). In the case of methyl acetate ester, for example, a methoxy group (—O—CH3), which is the simplest form of an alkoxy, has replaced the —OH group in acetic acid CH3COOH. This results in CH3COOCH3, or methyl acetate ester. This chemical reaction is commonly termed esterification. Diagram 1, found below, shows the chemical bond structures for these compounds.

Fatty acids consist mainly of carbon chains and hydrogen atoms. These chains can be short with a small number of carbon atoms, e.g., butyric acid (CH3CH2CH2COOH), or long with large number of carbon atoms, e.g., oleic acid CH3(CH2)7CH═CH(CH2)7COOH. Fatty acids may include single and double bonds between carbon atoms. A saturated fatty acid has the maximum number of hydrogen atoms covalently bound to each carbon atom in the chain of carbon atoms, i.e., a saturated fatty acid has no double bonds. An unsaturated fatty acid has at least one double bond between two carbon atoms. Diagram 2, found below, shows an example of saturated and unsaturated fatty acids.

SME is produced by the transesterification of soybean oil with methanol in the presence of a catalyst. Transesterification results in a class of organic reactions where one ester is transformed into another ester by interchanging at least one alkoxy. The catalyst is often an acid or base. For example, methanol is added to NaOH and added to soybean oil to separate fatty acid esters from glycerin. In this example, the mixture of NaOH, methanol, and soybean oil is often heated to accelerate the esterification step.
SME profile by percent and by molecular weight is given in Table 1, below.
TABLE 1Typical SME profileFatty MolecularMeltingPercent ofAcidCarbonWeightPointSME byNameDesignFormula and Structure(g/mole)(° C.)Weightmethyl  palmitateC16:0270.5  30.510.3 methyl  stearateC18:0298.5  39.1 4.7 methyl  oleateC18:1296.5−19.822.5 methyl  linoleateC18:2294.5−34.954.1 methyl  linoleateC18:3CH3(CH2CH═CH)3(CH2)7CO2CH3292.5−57.0 8.3
Biodiesel produced by typical methods suffers from a crystallization phenomenon when temperatures decrease. Although this crystallization phenomenon is not limited to biodiesel, the temperature at which biodiesel begins to crystallize is substantially higher than petroleum-based diesel fuel. The crystallized constituents can clog fuel filters in vehicles using biodiesel and thereby cut off the fuel supply to the engine. The temperature at which solids begin to precipitate, thus producing a cloudy mixture, is referred to as cloud point (C.P.). Saturated fatty acid ester constituents crystallize at a higher temperature than unsaturated fatty acid esters. To lower the temperature at which crystallization occurs and thereby lower the C.P. of the fuel, several techniques can be used, examples of which include blending with petroleum-based diesel, introducing additives, and winterization. Winterization refers to crystallization and removal of saturated fatty acids, e.g., C16:0 and C18:0, and in some cases mono-unsaturated fatty acids, e.g., C18:1, that cause the biodiesel product to crystallize at an undesirably high temperature. The crystallization process is typically performed by cooling, and the removal process is typically performed by filtration of the crystallized particles of the saturated and in some cases mono-unsaturated fatty acids which leaves a mixture having a greater amount of polyunsaturated fatty acids compounds with lower C.P., thereby lowering the C.P. of the biodiesel so produced.
The winterization process has gained more interest in recent years. Winterization by itself produces low yields, i.e., a substantial portion of the starting material is lost during the filtration process. Therefore, use of compounds which improve the winterization process, typically referred to as "improvers," is essential. One process which includes the addition of improvers is referred to as fractionation, which uses the crystallization properties of esterified fatty acids to separate a mixture into low and high C.P. liquid fractions. During fractionation, these improvers create inclusion compounds/complexes. The process of creating an inclusion compound involves a host constituent, namely, the fatty acid molecule, which has a series of cavities or landing sites for attachment by a second chemical constituent, commonly referred to as the guest, which is an improver compound. The compound resulting from the combination of the host and the guest is called an "inclusion compound." The forces that hold the host and the guest constituents together are van der Waals type forces. That is, covalent bonds do not typically form between the guest and the host. Clathrates are one type of inclusion compound in which the spaces in the host constituent are enclosed on all sides, causing a "trapping effect."
A common improver compound is urea. Urea selectively forms clathrates with fatty acid molecules. Initially, urea forms clathrates with longer straight chain saturated fatty acid molecules, e.g., C18:0. As the number of longer chain saturated fatty molecules decline, urea then forms inclusion compounds with shorter straight chain saturated fatty acids molecules, e.g., C16:0, and then with mono-unsaturated fatty acid molecules that are nonlinear, e.g., C18:1. The reason for this selectivity is thought to be the ease of clathration observed with longer linear chain saturated fatty acids due perhaps to these moleuces possessing a larger number of landing sites for the urea molecule.
There are three different types of fractionation: dry fractionation, detergent fractionation, and solvent fractionation. Solvent fractionation has received a substantial amount of interest in recent years. The key to efficient fractionation is to thoroughly mix the improvers, e.g., urea, with the fatty acids. Solvent is used as a carrier for the improver. That is, the improver is dissolved in the solvent and the solvent-improver combination is added to the fatty acid to make a homogenous mixture.
Addition of solvent-improver to the fatty acid esters alone, however, does not promote formation of clathrates. For example, if urea is dissolved in methanol and the urea-methanol mixture is added to a mixture of fatty acid esters to form a homogenous mixture, urea molecules preferentially stay dissolved in methanol rather than forming clathrates with the fatty acid esters. In order to initiate the desired clathration, a change in conditions must occur. In the prior art, in order to begin the clathration, the homogenous mixture is cooled. As the homogenous mixture is cooled, urea molecules begin to form clathrates based on the selectivity described above. The clathrates crystallize and can be separated by filtration, centrifugation, etc. As the homogenous mixture is formed the temperature is often elevated. This is due to heating in the transesterification phase in order to accelerate the esterification step, and since the homogenous mixture is often formed directly after the transesterification phase. The desired C.P. is directly proportional to how much the homogenous mixture is cooled. For ultralow C.P.s, the target cooling temperature is very low. Thus, due to a thermodynamic equilibrium, clathration formation slows unless the temperature is further reduced. In order to form additional clathrates, the temperature must be further reduced.
However, clathration by cooling has several disadvantages. First, cooling the homogenous mixture is costly and in some cases not possible. For example, in many developing countries, the requirement to cool the homogenous mixture is prohibitively expensive due, for example, to high ambient temperature under some conditions. Second, cooling takes a substantial amount of time. Large batches of fatty acid esters have correspondingly large thermal masses. Therefore, an undesirably long time may be required to reach the target cooling temperature. Even if the homogenous mixture is allowed to naturally cool to room temperature, and thereby eliminate the need for active cooling, a substantial amount of time may be required due to the thermal mass. Also, relying on naturally cooling to ambient temperatures may result in inconsistent output quality because the target cooling temperature may vary and the target temperature plays a key major role in the final product's C.P. Third, in cooling based processes involving typical target temperatures, some urea almost invariably stays dissolved in the solvent instead of forming clathrates. To quantify how much urea is used, urea utilization is defined as a ratio of urea that forms clathrates to the total amount urea supplied in the process. In the cooling process, urea utilization is always inherently below 100%. Fourth, the cooling process requires eventual separation of methanol from the unsaturated-rich fatty acid esters. This is required for commercial biodiesel because of industry standards set for the final product which limit the amount of methanol in biodiesel, e.g., to 0.2% by volume.
What is needed is a robust, fast and efficient method of lowering the cloud point of Biodiesel that overcomes the drawbacks of the art discussed above.

This patent is subject to a terminal disclaimer.

Method of lowering the cloud point of fatty acid esters


A new ternary sulfide alloy exhibits a metal-semiconductor phase transition with hysteresis as a function of temperature. One embodiment of the bistable material includes barium, cobalt, nickel and sulfur in amounts in accordance with the formula Ba(Co.sub.1-x Ni.sub.x)S.sub.2-y, and x is between 0 and 1 and y varies from 0 to 2.

Field of the Invention
This invention relates generally to a material which exhibits thermal bistability and in particular, to a ternary sulfide alloy which exhibits a metal-semiconductor phase transition with hysteresis as a function of temperature.
Background of the Related Art
A thermally bistable material exhibits hysteresis if its physical properties (e.g., resistivity, optical reflectivity and thermal conductivity) differ over a given temperature range when it is heated versus when it is cooled. Such bistable materials can be used to make a binary switch, whereby the switch is in a first state, (the "0" state) when the bistable material is in a first (physical) state, and the switch is in a second state (the "1" state) when the bistable material is in a second (physical) state. Additional applications of thermally bistable materials are discussed in "Metal-Semiconductor Phase Transitions in Vanadium Oxides and Technical Applications," by F. Chudnovskii, Soy. Phys. Tech. Phys. Vol. 20, p. 999 (1976) and "Optical Properties of Vanadium Dioxide and Vanadium Pentoxide Thin Films," E. Chain, Appl. Optics, Vol. 30, p. 2782 (1991).
Bistable materials typically change from a semiconducting state to a metallic state with an increase in temperature, i.e., from (1) a state in which the resistivity is large and decreases as the temperature increases (a semiconducting state) to, (2) a state in which the resistivity is small and increases as the temperature increases (a metallic state). Bistable materials which undergo a phase transition from a semiconducting state to a metallic state with an increase in temperature are said to have a negative temperature coefficient (NTC).
An example of a thermally bistable NTC material with hysteresis is vanadium dioxide (VO.sub.2). In addition to being used in binary switches, vanadium dioxide has been used to make heat pipes and sensor elements. Nevertheless, it is sometimes advantageous that the thermally bistable material have a positive temperature coefficient (PTC), i.e., the material changes from a metallic phase to a semiconducting phase with increasing temperature as discussed, for example, in "Understanding doped V.sub.2 O.sub.3 as a Functional Positive Temperature Coefficient Material," by B. Hendrix et. al, J. Mater. Sci. Mater. Elect., Vol. 3, p. 113 (1992). These advantages can include low resistivity, high thermal conductivity and desirable optical properties on the low temperature side of the transition.
It is also desirable to be able to control the temperature at which the bistability occurs. For example, if the bistable material is being used to make temperature sensing switches, it may be necessary that some of these switches undergo a phase transition at a first temperature while others of these switches undergo the phase transition at a second temperature. A useful bistable material should exhibit different transition temperatures with small changes in the chemical composition or with the application of easily accessible pressures.
Quite apart from the study of bistable materials is the study of new barium ternary alloys. For example, U.S. Pat. No. 2,770,528 discusses barium ferrous group metal ternary sulfides such as barium cobalt sulfide (BaCoS.sub.2) or barium nickel sulfide (BaNiS.sub.2). However, neither of these compounds are thermally bistable materials and consequently, neither BaCoS.sub.2 nor BaNiS.sub.2 exhibits a metallic-semiconducting phase transition such as observed in vanadium dioxide.

Sulfide alloys that exhibit thermal bistability

The University of Iowa Research Foundation


Disclosure is made of a laser system comprising a non-linear crystal that converts light at a fundamental wavelength to light at a harmonic wavelength and that has a thickness such that there is a phase mismatch between light at the fundamental wavelength and light at the harmonic wavelength in said crystal; first means for forming one of a travelling wave optical cavity and a standing wave optical cavity at the fundamental wavelength; and second means for forming one of a travelling wave and a standing wave optical cavity at the harmonic wavelength, the first means and said second means are located relative to the faces of said crystal such that the total phase mismatch of the light at the fundamental wavelength and the light at the harmonic wavelength, in the round trip path through the crystal and between each face of the crystal and the first means and the second means, is equal to an integral multiple of 2.pi..

The process of "second harmonic generation" (SHG) is one of a number of non-linear optical (NLO) processes (e.g., difference-frequency generation, sum-frequency generation, optical mixing, parametric oscillation, etc.) by which light at one wavelength is converted into light of another wavelength. Specifically, in a SHG process, light at a fundamental wavelength (i.e., angular frequency .omega.) is converted to light having a wavelength of one half (i.e., 2.omega.) of the fundamental (e.g., the second harmonic). Thus, using an appropriate NLO material, two photons can be added together in a SHG process to result in a single photon of higher energy. Second harmonic generation has been reviewed by A. Yariv in Quantum Electronics, 2nd Ed., John Wiley & Sons, New York, 1975, pp. 407-434 and by W. Koechner in Solid State Laser Engineering, Springer-Verlag, N.Y., 1976, pp. 491-524.
Materials having non-linear optical properties are well known. For example, U.S. Pat. No. 3,949,323, issued to Bierlein et al. on Apr. 6, 1976, discloses that non-linear optical properties are possessed by materials having the formula MTiO (XO.sub.4) where "M" is at least one of K, Rb, Ti, or NH.sub.4 and "X" is at least one of P or As, except when NH.sub.4 is present, then "X" is only P. This generic formula includes potassium titanyl phosphate, KTiOPO.sub.4, or KTP, which is a particularly useful non-linear material. Other known non-linear optical materials include, but are not limited to, KH.sub.2 PO.sub.4 or KDP, LiNbO.sub.3, KNbO.sub.3, .beta.-BaB.sub.2 O.sub.4, Ba.sub.2 NaNb.sub.5 O.sub.15, LilO.sub.3, HlO.sub.3, KB.sub.5 O.sub.8 4H.sub.2 O, potassium lithium niobate and urea. A review of the non-linear optical properties of a number of different uniaxial crystals has been published in Sov. J. Quantum Electron., Vol. 7, No. 1, January 1977, pp. 1-13. Non-linear optical materials have also been reviewed by s. Singh in the CRC Handbook of Laser Science and Technology, Vol. III, M. J. Weber, Ed., CRC Press, Inc. Boca Raton, Fla., 1986, pp. 3-228.
Electromagnetic waves having a frequency in the optical range and propagating through a non-linear crystal induce polarization waves which have frequencies equal to the sum and difference of those of the exciting waves. Such a polarization wave can transfer energy to an electromagnetic wave of the same frequency. The efficiency of energy transfer from a polarization wave to the corresponding electromagnetic wave is a function of (a) the magnitude of the second order polarization tensor, since this tensor element determines the amplitude of the polarization wave; and (b) the distance over which the polarization wave and the incident electromagnetic wave can remain sufficiently in phase.
The coherence length, I.sub.c, is a measure of the phase relationship between the polarization wave and the incident electromagnetic wave and is given by the following relationship: EQU I.sub.c =.pi./.DELTA.k
where ".DELTA.k" is the difference or mismatch between the wave vectors of the polarization and incident electromagnetic waves. More specifically, the coherence length is the distance from the entrance surface of the non-linear optical crystal to the point at which the power of the radiated electromagnetic wave will be at its maximum value. "Phase-matching" occurs when .DELTA.k=0. The condition .DELTA.k=0 can also be expressed as n.sub.3 .omega..sub.3 =n.sub.1 .omega..sub.1 .+-.n.sub.2 .omega..sub.2 where .omega..sub.3 =.omega..sub.1 .+-..omega..sub.2 ; .omega..sub.1 and .omega..sub.2 are the frequencies of the input electromagnetic waves; .omega..sub.3 is the frequency of the radiated output electromagnetic wave; and and n.sub.1, n.sub.2 and n.sub.3 are the refractive indices of the respective waves in the non-linear optical crystal. In the special case of second harmonic generation, there is incident radiation of only one frequency, .omega.; therefore .omega..sub.1 =.omega..sub.2 =.omega. and .omega..sub.3 = 2.omega..
For appreciable conversion of optical radiation of one frequency to optical radiation of another frequency in a non-linear optical crystal, the interacting waves must stay substantially in phase throughout the crystal so that: EQU .vertline..DELTA.k.vertline.=.vertline.k.sub.3 -k.sub.1 -k.sub.2 .vertline.<.pi./L
where k.sub.1, k.sub.2 and k.sub.3 represent the wave numbers corresponding to radiation of frequencies .omega..sub.1, .omega..sub.2, and .omega..sub.3, respectively, and "L" is the interaction length in the non-linear material. In the special case of second harmonic generation: ##EQU1##
The term "substantially phase-matched," as used herein, means that .vertline..DELTA.k.vertline.<.pi./L for a given non-linear optical crystal.
A conventional method for achieving phase-matching in a non-linear optical material utilizes the fact that dispersion (i.e., the change of refractive index with frequency) can be offset by using the natural birefringence of uniaxial or biaxial crystals. In a typical case (Type I phase matched second harmonic generation) the fundamental and harmonic beams are orthogonally polarized in directions corresponding to the principal refractive indices of the crystal. The birefringence of the crystal is adjusted to compensate for the dispersion between the fundamental and harmonic radiation, thereby preserving the phase relationship between the two beams as they travel through the crystal. This technique, or modifications of it, can be used to achieve `true` phase matching of a number of different nonlinear interactions including sum and difference frequency mixing and second harmonic generation.
Engineering the optical properties of an existing material provides an alternative to materials in which true phase-matching can be achieved. Quasi phase-matching (QPM) compensates for refractive index dispersion in nonlinear optical interactions. Unlike techniques which utilize the birefringence of anisotropic materials, QPM can be applied to isotropic materials or to interactions in which the interacting waves have the same polarization. The doubling crystal can be tailored to phase-match any given wavelength at room temperature by setting the period of the alternating nonlinearity to be twice the anticipated coherence length.
Three methods of achieving quasi phase-matching have been described in "Interactions between Light Waves in a Non-linear Dielectric" by J. A. Armstrong et al., Physical Review, Vol. 127, pp. 1918-1919 Sep. 15, 1962).
Continuous power flow from the fundamental into its second harmonic can be maintained along the length of a crystal by changing (e.g., "periodic poling" or "domain reversal") the sign of the nonlinear coefficient of the material at odd multiples of the coherence length. For periodic poling, the crystal must be stable after the periodic structural changes are made. In addition, surface and crystal quality must be such that losses due to optical scattering and absorption are low. This is not always possible. Periodic poling has been used in conjunction with lithium niobate to generate green and blue light. See Magel et al., "Second harmonic generation of blue light in periodically poled lithium niobate", CLEO-89, paper ThQ3, and Lim et al., "Second harmonic generation of green light in a periodically poled lithium niobate waveguide", CLEO-89, paper ThQ4. Also see U.S. Pat. No. 4,731,787 to Fan et al (i.e., FIG. 3).
Another method involves total internal reflection of both the fundamental and harmonic waves in a crystal of thickness: EQU d=.pi. cos .THETA./.vertline.k.sub.2 -2k.sub.1 .vertline.
where "k.sub.2 -2k.sub.1 " is the wave vector mismatch, and ".THETA." is angle between the beam propagation direction and a normal to the crystal surface. This method has been used successfully to phase-match second harmonic generation of 10.6 .mu.m radiation in GaAs. See "Enhancement of Optical Second-Harmonic Generation (SHG) by Reflection Phase Matching in ZnS and GaAs," Boyd and Patel, Appl. Phys. Letters, 8, (1966) p. 313.
The final method, and the one to which the present invention is addressed, involves resonating the second harmonic in a crystal platelet which has a length L which is given by: ##EQU2## where .pi./.vertline.k.sub.2 -2k.sub.1 .vertline. is the coherence length for the interaction. Heretofore, this technique for achieving QPM does not appear to have been exploited by the art. In accordance with this method, if a monochromatic traveling wave is incident upon a "harmonic etalon" at a frequency which is one half that of one of its resonances, a harmonic wave is produced in the forward direction but not in the reverse.
Second harmonic generation within the cavity of a multi-longitudinal mode laser by an intercavity doubling crystal has been analyzed by T. Baer, J. Opt. Soc. Am. B, Vol. 3, No. 9, (1986) pp. 1175-1180. U.S. Pat. Nos. 4,656,635 and 4,701,929, both issued to Baer et al., disclose a laser diode-pumped, intracavity frequency-doubled, solid-state laser. A detailed theoretical analysis of a multi-longitudinal mode intracavity-doubled laser has been reported by X. G. Wu et al., J. Opt. Soc. Am. B, Vol. 4, No. 11, (1987) pp. 1870-1877.
In U.S. Pat. No. 4,847,851, G. J. Dixon disclosed a compact, diode-pumped, solid-state laser wherein the diode pump is butt-coupled to a laser gain material which absorbs 63% of the optical pumping radiation within a pathlength of less than 500 microns. In such a device, a divergent beam of optical pumping radiation from the diode pump is directed into a volume of the gain medium which has a sufficiently small transverse cross-sectional area so as to support only single transverse mode laser operation. Optical lenses are not needed for coupling.
J. J. Zayhowski and A. Mooradian, "Single-frequency Microship Nd Lasers," Optics Letters, Vol. 14, No. 1, (Jan. 1, 1989) pp. 24-26, have reported the construction of single-frequency microchip lasers which have a miniature, monolithic, flat-flat, solid-state cavity (e.g., 730 micron long cavity) whose mode spacing is greater than the gain bandwidth of the gain medium, and which are longitudinally pumped with the close-coupled, unfocused output of a laser diode.
The conversion of optical radiation at one frequency into optical radiation of another frequency by interaction with a non-linear optical material within an optical cavity is disclosed in U.S. Pat. No. 4,933,947 to D. W. Anthon and D. L. Sipes, "Frequency Conversion of Optical Radiation," which is assigned to the assignee of the present invention. A diode-pumped laser having a harmonic generator is disclosed by Robert Byer, G. J. Dixon and T. J. Kane in U.S. Pat. No. 4,739,507 and in an article by Byer, "Diode Laser-Pumped Solid-State Lasers," Science, Vol. 239, (Feb. 1, 1988) p. 745.
There are many practical applications of a method and apparatus which achieve harmonic conversion in a solid-state laser resonator, which is adopted to a wide variety of NLO materials, which have the advantages of small size, efficient lasing in a close-coupled pump geometry and ease of assembly, and which produce SHG outputs which are substantially greater than what might be expected from the physical size of the NLO material. Such a microlaser will not only have wide applications in the production of visible light, but also will be easy to manufacture on a mass production scale, thereby lowering costs and leading to even more practical uses.

Intracavity harmonic sub-resonator with extended phase matching range


A solid X-ray target for generating X-ray radiation is disclosed. The X-ray target includes at least one material selected from a list including trivalent elements; and at least one material selected from a list including pentavalent elements, wherein a first one of the materials is capable of generating the X-ray radiation upon interaction with an electron beam, and a second one of the materials forms a compound with the first one of the materials. An X-ray source including such an X-ray target and an electron source is also disclosed.

X-ray radiation may be generated by letting an electron beam impact upon a solid anode target. Traditionally, the solid anode target is formed of an element with a high atomic number, such as tungsten or copper, in order to maximize the X-ray yield. However, in practice, the generation of X-ray radiation is often limited by the thermal properties of the solid anode materials. Heat capacity, thermal conductivity and melting point are examples of thermal properties which, when limited, may lead to overheating, target consumption and a poor control of the quality of the generated X-ray radiation. Trivalent, such as gallium or pentavalent, such as arsenic, pure elements have also been contemplated as solid anode target materials, but their ability to produce X-ray radiation is often limited by their thermal properties.
Furthermore, traditional X-ray targets, such as tungsten or copper targets, produce X-ray radiation that is not suitable for studying several types of material systems, e.g. silicon based systems comprising copper structures.
Even though solid X-ray targets exist in the art today, there is still a need for improved targets for generating X-ray radiation. In particular, there is a need for solid X-ray targets with improved thermal properties.


(1S, 3S)-3-Amino-4-difluoromethylene-1-cyclopentanoic acid illustrates a novel class of compounds as potent irreversible inhibitors of γ-aminobutyric acid aminotransferase (GABA-AT). The corresponding monofluoro-substituted compounds also are potent time-dependent inhibitors of GABA-AT.

Epilepsy is an important central nervous system disease characterized by recurring convulsive seizures. It has been shown that convulsions arise when an imbalance exists between two principal neurotransmitters, L-glutamic acid, an excitatory neurotransmitter, and γ-aminobutyric acid (GABA), an inhibitory neurotransmitter. Two enzymes, glutamic acid decarboxylase (GAD) and γ-aminobutyric acid aminotransferase (GABA-AT), regulate the level of GABA in the brain. GAD synthesizes GABA from L-glutamic acid. GABA-AT, which is a pyridoxal-5′-phosphate (PLP, 1) dependent enzyme, converts GABA to succinic semialdehyde. During transamination, PLP is converted to pyridoxamine-5′-phosphate (PMP), which is transformed back to PLP by a reaction with 2-ketoglutarate; the 2-ketoglutarate is converted to L-glutamic acid. Succinic semialdehyde dehydrogenase (SSDH) oxidizes succinic semialdehyde to succinic acid using NADP+ as the cofactor (Scheme 1).

When the level of GABA in the brain falls below a threshold level, convulsions occur. Taking GABA orally is not effective in raising the GABA level in the brain because GABA cannot cross the blood-brain barrier. One promising approach is to inhibit GABA-AT, which degrades GABA. The level of GABA would increase due to its continuous production. The catalytic mechanism of GABA-AT is shown in Scheme 2. The cofactor PLP is bound to Lys329 in the form of a Schiff base. (Storici, P.; Capitani, G.; Biase, D. D.; Moser, M.; John, R. A.; Jansonium, J. N.; Schirmer, T. Crystal Structure of GABA-Aminotransferase, a Target for Antiepileptic Drug Therapy. Biochemistry, 1999, 38, 8628-8634.) Transimination gives the imine between GABA and PLP. The enzyme then removes the γ-proton of GABA to give the aldimine, which is subsequently hydrolyzed to produce succinic semialdehyde and PMP.
In the art, it is understood by definition that a mechanism-based irreversible inhibitor is an unreactive compound that has a structural similarity to the substrate or product for the target enzyme and is converted by the target enzyme into a species that inactivates the enzyme prior to its release from the active site. (Silverman, R. B. Mechanism-Based Enzyme Inactivation: Chemistry and Enzymology, Vol. 1; CRC Press: Boca Raton, 1988.) One such inhibitor is the rationally designed vigabatrin (2), an epilepsy drug marketed all over the world, except in the U.S., which irreversibly inhibits GABA-AT by the mechanisms shown in Scheme 3. Pathway a (Michael addition) has been determined and found to account for about 70-75% of the total inactivation. (Nanavati, S. M.; Silverman, R. B. Mechanisms of Inactivation of γ-aminobutyric Acid Aminotransferase by the Antiepilepsy Drug γ-Vinyl GABA (Vigabatrin). J. Am. Chem. Soc. 1991, 113, 9341-9349.)

Previously, 3, a conformationally-rigid vigabatrin analogue, was synthesized.
Surprisingly, 3 was not a GABA-AT inactivator but was a very good substrate (Km=0.1 mM, kcat=11.7 min−1, kcat/Km=117 mM−1 min−1) with a specificity constant almost six times greater than that of GABA (Km=2.4 mM, kcat=49 min−1, kcat/Km=20.4 mM−1 min−1). It was later determined by computer modeling that the endocyclic double bond is not in the right orientation for Michael addition (pathway a, Scheme 3), nor is it an effective enamine for enzyme inactivation. Therefore 7, which has an exocyclic double bond, was designed and prepared from diketone 4, as shown in Scheme 4. (Qiu, J.; Pingsterhaus, J. M.; Silverman, R. B. Inhibition and Substrate Activity of Conformationally Rigid Vigabatrin Analogues with γ-Aminobutyric Acid Aminotransferase. J. Med. Chem. 1999, 42, 4725-4728.) An addition reaction with (trimethylsilyl)methylmagnesium chloride followed by elimination furnished 6. Deprotection of the benzyl group and hydrolysis of the lactam gave the amino acid 7. (Specific reagents and conditions: (a) TMSCH2MgCl, −30° C. to RT, 38%; (b) (CF3CO)2O, DMAP, then TBABr, KF, 86%; (c) Na/NH3/tBuOH,; (d) 2N HCI, 90%, 2 steps.)

Interestingly, 7 inactivated GABA-AT, but when 2-mercaptoethanol was added to the incubation mixture, no inactivation was observed. A possible mechanism accounting for this phenomenon is shown in Scheme 5. It is likely that 7 is only a substrate for GABA-AT. After formation of 8, the double bond is not reactive enough, so this intermediate is not trapped by the enzyme, but rather is released from the active site in the form of an α,β-unsaturated ketone (9). In the presence of 2-mercaptoethanol, a reactive nucleophile, 9 is trapped to form 10, giving no inactivation
of the enzyme. In the absence of 2-mercaptoethanol, however, 9 may return to the enzyme and become covalently attached to the enzyme (11), leading to the enzyme's inactivation. According, however, to definitions, prior art compound 7 is not a mechanism-based inactivator inasmuch as inactivation does not occur prior to the release of the active species from the active site.

Compounds and related methods for inhibition of gamma-aminobutyric acid aminotransferase


The present invention provides an electrode for electroluminescence for use in electronic devices including organic electroluminescent devices and a process for producing the same, in which interfacial electric characteristics, such as work functions, can be easily controlled. The process for producing an electrode for electroluminescence comprises the step of diffusing an additive element for an electrode into the electrode and/or the step of developing surfactant properties of the additive element for an electrode.

In the electroluminescence industry, what has hitherto been demanded is the control of interfacial electric characteristics of electrodes for electroluminescence. Interfacial electric characteristics of electrodes, such as work function, affect the efficiency of charge injection into a luminescent layer and greatly influence luminescence efficiency. For this reason, an attempt has hitherto been made to control the relationship between work functions of electrode materials. In this case, a complicated process, for example, involving intentional provision of interlayer materials has been adopted rather than the adoption of control utilizing diffusion and surfactant properties. The provision of very thinly controlled layers of these materials, however, disadvantageously complicates the production process and increases the production cost.

Electrode for electroluminescence and electroluminescent device using the same


An information processing apparatus for effecting recording of information on and/or reproduction of information from a recording medium is provided with a probe electrode, a cantilever piezo-electric member, a controller and a detector. The probe electrode is relatively displaced to the recording medium by the cantilever piezo-electric member. The controller applies a control signal to the cantilever piezo-electric member to control the cantilever piezo-electric member. The detector detects a minute signal obtained on the tunnel effect caused between the probe electrode and the recording medium. A switch element is further provided on the apparatus so as to electrically disconnect between the cantilever piezo-electric member and the controller during the minute signal being detected by the detector.

1. Field of the Invention
This invention relates to an information processing apparatus which two-dimensionally scans a medium by a probe and effects recording and reproduction by the physical interaction of the medium and the probe, or to a scanning type tunnel electronic microscope (STM). The invention, more particularly, relates to an STM and a compact and high-density information processing apparatus to which the principle of the STM is applied.
2. Related Background Art
In recent years, there has been developed a scanning type tunnel microscope (hereinafter referred to as STM) which can directly observe the electron structure of the surfaces of substances and the vicinity of the surfaces (G. Binnig et al., Helvetica Physica Acta. 55. 726 (1982)), and it has become possible to observe real spatial images at a high resolving power irrespective of single crystal or noncrystal and moreover, this STM has the advantage that measurement can be accomplished with low electric power substantially without imparting damage by electric current to sample substances, and further it operates not only in super-light vacuum but also in the atmosphere and in solution and can be applied to various materials. Therefore, its wide application is expected.
The STM utilizes the phenomenon that when a voltage is applied to between a metallic probe and an electrically conductive sample and the probe is brought to a distance of about 1 nm with respect to the sample, a tunnel current is created. Recently, as disclosed, for example, in Japanese Laid-Open Patent Applications Nos. 63-161552 and 63-161553, there have been made numerous proposals to utilize the principle of this STM to construct an information processing apparatus directed chiefly to high-density recording and reproduction. That is, it is said that if use is made of a method of imparting physical deformation onto a recording medium corresponding to a sample by a probe electrode corresponding to the probe of the STM, or varying the electron state of the surface of the medium to thereby record information, and reproducing the information of a recording bit by a tunnel current flowing between the probe electrode and the recording medium, large-scale information can be recorded and reproduced at high density of the molecular or atomic order.
It has recently been reported that in the above-described recording method, to impart physical deformation onto the recording medium, a hole can be formed not only by urging a pointed recording probe against the recording medium to thereby dent the latter, but also by applying a pulse voltage onto a recording medium such as graphite. That is, the probe electrode is brought close to the surface of the recording medium, and then applying a voltage of 3-8 V with a pulse width of 1-100 .mu.s to between the two, a hole having a diameter of the order of 40 angstroms can be formed, and such a hole is readily usable as a recording bit. On the other hand, to vary the electron state to thereby effect recording, there is known a method of applying a voltage to between a recording medium and a ground electrode and a probe electrode to thereby vary the electrical resistance characteristic of a minute portion, and attention has been paid to this method because of the ease of erasing and rewriting.
As the recording medium, use is made of a thin film layer of a material such as a chalcogenide or an organic compound of the .pi. electron family which exhibits a switching characteristic having a memory property in a voltage-current characteristic, for example, a cumulative film of an appropriate organic substance made on a ground electrode by Langmuir-Blodgett's technique (hereinafter referred to as LB technique).
The probe electrode is usually, for example, a needle tip of tungsten, Pt-Ir, Pt or the like mechanically polished and thereafter polished by an electric field and attached to a piezo-electric element, and displacement-controlled by an applied voltage. As a method of making a flexible portion for moving the probe electrode, there is, for example, a working technique making a minute structure on a substrate (K. E. Peterson, "Silicon as Mechanical Material", Proceedings of the IEEE, 70, Vol. 420 p, 1982) by using a semiconductor processing technique. Thereby, it has become possible to form a hole portion 30 in a single crystal silicon substrate 21 shown, for example, in FIG. 9 of the accompanying drawings, to provide a tongue-like finely moving mechanism 2 on the silicon substrate 21 by cantilever support, and mount a probe electrode 1 on the front end thereof.
The tongue-like portion 2 is comprised of a layer-like piezo-electric element and electrodes, and by applying voltage between the electrodes, the probe electrode is varied in a direction perpendicular to the plane of the single crystal silicon substrate 21 (the direction of the Z axis). As regards displacement in XY direction, relative movement is effected by the silicon substrate or a medium opposed thereto being installed on a stage capable of scanning. Of course, at this time, there can be realized a memory device provided with a converter array having a number of tongue-like portions 2 arranged thereon. Besides the tongue-like portion 2 of such cantilever structure, a tongue-like portion of a bridge-like twin beam structure is also known.
It is very important in achieving the compactness, the great capacity and the high speed of an information processing apparatus to form a probe having a finely moving mechanism by minute working. On the other hand, however, it results in crosstalk and deterioration of S/N ratio because a signal system for driving and a signal system for recording and reproduction come very close to each other.

Information processing apparatus and scanning tunnel microscope


A light projection apparatus for projecting an illuminated line onto a surface which comprises a light source for emitting a light beam and a light beam deflection lens which is adapted to receive the emitted light beam and project a work light beam which will be visible as a straight line on the surface, the light deflection lens is configured so that the visible line on the surface is of generally equal illumination along its entire length. The light beam deflection lens preferably comprises an optical lens which is adapted to refract and reflect the emitted light beam.

1. Field of the Invention
This invention relates to a light projection apparatus, in particular, an apparatus for projecting an illuminated line onto a workpiece.
2. Description of the Prior Art
In a number of industries, for example, timber sawmills, stone masonry, the textile industry, etc., frequently a requirement is to saw, grind or cut the products concerned along straight lines, which may be of considerable lengths, sometimes up to 12 meters or more.
The conventional methods of guiding the cutting machinery involved include the use of chalk lines, strips, straight edge rules and so forth. These methods are clumsy, difficult to apply and are easily displaced by the operations in progress.
More recently, the use of lasers projecting a long thin line of light on the workpiece have come into use. This system represents a major improvement over the older conventional methods. However, a disadvantage of existing laser systems, particularly where very long lines are required, is that the intensity of the light is greatly reduced towards the far end of the projected line, and this, combined with the unavoidable small angle of incidence of the bream on to the workpiece at the far area, makes if difficult to distinguish the line clearly.
The known art utilizes a lens system comprising a solid cylindrical glass rod to fan out the rays of a laser beam to produce a line of laser light on the surface of the object when the beam is projected on to such an object.
In FIG. 1, curve C1 shows the comparative intensities of the light produced by this system at different angles emanating from the light source. As can be seen, the intensity is greatest over the center portion of the beam (at x), gradually reducing to zero towards the outer ends of the beam.
FIG. 2 shows a typical layout of an arrangement for projecting a line of light AB, from laser 1, on to a workpiece. Curve C2 shows the comparative brightness resulting at various points along this line. As can be seen, bright illumination is provided on the portion of the line nearer to the light source, while on the portion further from the source the level of illumination is substantially lower. This is accounted for by a combination of factors, each of which materially contributes to this unsatisfactory situation.
The factors are:
1. The greater distance from the light source. PA1 2. The comparatively lower intensity of light emanating from the lens in the outer portion of the beam. PA1 3. The very oblique angle at which the light strikes the surface of the workpiece at this end of the line, resulting in an already reduced relative light intensity being spread over a long length of the line.
A device sometimes employed to improve this result is to offset the solid cylindrical lens from the center line of the laser beam. This results in a higher proportion of light being projected from the lens to one side of the beam as compared with the other side. Curve D in FIG. 1 illustrates the comparative light intensities obtained with such a prior art device in which the beam from the light source is offset from the axis of the lens used to deflect the beam onto the work surface. This effect is utilized to increase to some extent, the portion of light transmitted to the more distant portion of the line. However, even with this modification, the variation in illumination of the line from one end to the other is considerable.
DE 43 20 177 discloses a light projection apparatus which is used to project an illuminated line onto a surface. The disclosed apparatus utilizes a laser source to emitting a laser beam. A specially shaped prism receives the emitted laser beam and refracts it in such a way as to produce a fanned beam which forms a line of light on the surface. There is a generally constant intensity of illumination in the line of light.
Apart from the difficulties of manufacturing the specially shaped prism to achieve the desired refraction, the disclosed apparatus has the disadvantage that it the fanned laser beam is projected symmetrically onto the surface about an axis at right angles to the surface. This makes it unsuitable from projecting rather long illuminated lines onto the surface, because the longer the line, the further away from the surface the laser projection apparatus must be situated.
Therefore, in light of the deficiencies of the prior art, it is an object of the invention to provide a system in which a line of laser light may be projected on to a surface situated obliquely relative to the light source, such a line of light being substantially evenly illuminated throughout its length, and thus more easily visible at all points along its length.

Light projection apparatus for projecting a line of generally constant illumination on a surface

Afgen House, 26 Kyalami Boulevard, Kyalami Business Park


There is provided a method and a device capable of holding a sheet-like workpiece without wrinkles. The sheet-like workpiece holding method includes mounting the sheet-like workpiece such that almost no tensile force is applied thereon on a machining table, and pressing out wrinkles of the sheet-like workpiece by lowering a pressing member whose surface facing to the workpiece protrudes in the shape of a convex lens toward the workpiece so that the workpiece is pressed against the machining table. The method also includes retaining the sheet-like workpiece on the machining table using suction while continuously pressing the sheet-like workpiece with the pressing member and releasing the pressing force of the pressing member while retaining the sheet-like workpiece.

1. Field of the Invention
The present invention relates to a method and a device for holding a sheet-like workpiece by rolling out the sheet-like workpiece wound in a roll to hold a part thereof on a flat table. The invention is suitably applicable to a laser machining apparatus for machining a flexible printed board for example.
2. Description of the Prior Art
As a machining apparatus for machining a sheet-like workpiece, there has been known a laser machining apparatus having, successively, an unwinding unit for unwinding a non-machined material wound in a roll, a machining unit having a machining section (laser head) for drilling the non-machined material and a take-up unit for taking up the finished material in a roll as disclosed in Japanese Patent Laid-Open No. 2004-195510 for example. The laser machining apparatus also includes a machining table disposed so as to be movable relative to a main frame of the machining apparatus such that a plurality of blocks of the non-machined material can be moved and positioned in a longitudinal direction of the material for machining by the machining section. The laser machining apparatus also includes clamp means disposed in a body of the machining table and operates so as to clamp the non-machined material with respect to the machining table when the machining table moves from a starting position to an ending position and to release the non-machined material from the machining table when the machining table returns to the starting position. Moreover, the laser machining apparatus includes relative position fixing means that operate to fix relative positions of the non-machined material to the machining apparatus before releasing the non-machined material from the clamp means when the machining table reaches the end position and so as to release the fixed state of the relative position of the non-machined material to the machining apparatus after clamping the non-machined material with the clamping means when the machining table returns to the starting position.
This technology makes it possible to prevent the position of a printed board, i.e., a sheet-like workpiece, from deviating from the laser head and hence improves machining efficiency.
It is noted that the sheet-like printed board is often positioned on the machining table by applying a slight tensile force between a feed roll and a take-up roll, and by fixing the printed board on the machining table using suction or fixtures such as a clamper.
There has also been known a laser machining apparatus having at least a pair of clamps for holding both ends of a material to be machined and a tensioning unit for applying bias between the pair of clamps in a direction of relatively separating from each other to apply a tensile force to the non-machined material as disclosed in Japanese Patent Laid-Open No. 1998-296473 for example.
Since this technology allows the material to be kept flat even if it is apt to curl, it allows machining accuracy to be improved.
Moreover, in laser drilling a printed board on which copper foil is provided, etching is carried out before the drilling and a thickness of the printed board becomes uneven due to etching. Therefore, the printed board wound in a roll after etching causes wrinkles formed almost in parallel with a running direction the printed board.
The wrinkles formed almost in parallel with the running direction are unable to be removed even if a tensile force is applied in the running direction of the printed board. Therefore, the printed board on which etching process has been carried out is held on the table while having the wrinkles.
Although no hole can be machined, causing defective machining, at the wrinkled part because it is out of focus in case of laser machining, no consideration has been given to the wrinkles running almost in parallel with the running direction of the sheet-like workpiece in Japanese Patent Laid-Open Nos. 2004-195510 and 1998-296473.
Accordingly, it is an object of the invention to provide a method and a device capable of holding a sheet-like workpiece on a table without wrinkles.
This object may be achieved through the combination of features described in independent claims of the invention. Dependent claims thereof specify preferable embodiments of the invention.

Method and device for holding sheet-like workpiece


The invention provides methods for the rapid identification and selection of cell lines suitable for biopharmaceuticals production, which do no utilize animal derived components.

Mammalian cells such as CHO (Chinese Hamster Ovarian cells), NS0 and PerC6 cells are routinely employed within the biopharmaceutical industry to manufacture biopharmaceuticals. These cells are genetically engineered and then selected in such a way so as to ensure that high titre expression of the desired protein is observed when the resulting cell lines are cultured in bioreactors.
Currently all approaches to select the best secreting cell clones involve the screening of hundreds to thousands of transfected cells to identify preferred clones with optimal growth and production profiles (e.g. see Wurm, 2004, Nature Biotechnology 22, 1393-1398). All such methodology requires considerable time and effort. As a consequence there is ongoing need for improved methodology to select for high yielding and stable cell lines. Such methodology should be faster, less labour and less resource intensive than current methodology. Typical current cell line development protocols involve the delivery of desired expression and selection cassettes into a desired host cell followed by plating, selection and growth of resulting genetically engineered cells in serum and animal derived component free (ADCF) media. Such ADCF media, first developed in the early 1990s, are now regularly employed to select and grow recombinant cells producing biopharmaceutical proteins intended for clinical use. The use of such cell culture media for this purpose ensures the mammalian cell lines generated are not exposed inadvertently to adventitious or transmissible agents of known or unknown origin. The use of such ADCF media thus forms part of a strategy to ensure resulting cell lines and thereby biopharmaceutical cell banks, processes, manufacturing plants and final products are not contaminated by such adventitious and transmissible agents be they cellular, viral or protein in origin. The use of ADCF media as part of a strategy to ensure contamination-free manufacturing not only addresses a theoretical risk to patients and manufacturing plants: biological drug products have previously been adulterated with adventitious agents (e.g. Huang W T et al Pharmacoepidemiol Drug Safety 2010, 19(3):306-310) and manufacturing sites have previously been closed due to contamination with such agents (e.g. see Garnick R L Dev Biol Standard 1998: 93 pp 21-9 & FDA web site notification (June 2009) regarding Vesivirus contamination of a manufacturing plant's bioreactors). Further details on such considerations and how best to reduce risks are well documented in ICH Quality Guide Q5A "Safety Evaluation of Biotechnology Products Derived From Cell Lines of Human or Animal Origin" (Step 4 Version September 1999).
Certain cell screening methodologies designed to identify optimal genetically engineered producer cells employ flow cytometry in order to reduce time and effort. When using flow cytometry to select engineered cell lines that secrete high levels of desired recombinant protein, two approaches have been adopted.
The first approach involves the selection of cells in which a fluorescent co-marker (e.g. GFP) or an enzyme such as DHFR (when combined with a fluorescent substrate) is over expressed. For such selection methods to succeed, one must attempt to link the expression of the markers with expression of the desired protein products. This linkage is required to ensure that cells expressing high levels of the marker also express and secrete high levels of the desired protein product. Examples of such an approach include Yoshikawa T et al 2001 (Biotech and Bioeng 74: 5 pp 435-442), Meng Y. G et al 2000 (Gene 25:242 (1-2) 201-207), deMaria et al 2007 (Biotechnol Prog 23, 475-72) and US 2004/0148647. However, there are drawbacks to this approach, in particular the fact that one is primarily selecting for high levels of marker expression and this does not always correlate with high expression and secretion of desired protein product. This approach also results primarily in the selection of final cells expressing extremely large amounts of marker. This can be disadvantageous, since high expression of a marker will compete with the desired protein product for host cell transcription, translation and processing apparatus, and thus the ultimate yield of the desired protein may be reduced. Furthermore such marker proteins can also be toxic (Liu H S et al 1999 (Biochem Biophys Res Commun 260 (3): 712-7)) and thereby inhibit cell line growth and production.
The second approach involves the direct selection of cells that secrete high levels of desired protein product. For an overview of FACS in general, see Shapiro: Practical Flow Cytometry, Fourth Edition, 2003, Wiley-Liss, ISBN#9780471411253. In a broad sense there are two FACS based methods for selection of high expression clones directly.
The first 'direct selection' FACS-based method exploits the observed correlation between membrane bound levels of desired protein product with secretion levels. An example of this approach can be found in Marder P et al 1990 Cytometry 11: 498-505. In this study the authors stained the membrane of hydridoma cells with fluorescently conjugated anti-product antibodies and then sorted and selected the most highly fluorescent cells. They then demonstrated that the resulting sub-clones exhibited enhanced IgG secretion levels in comparison to the cells prior to sorting. Subsequent reports with different cell lines have demonstrated similar results (e.g. see Brezinsky S et al 2003. Jn of Immunol (2003) 141-155).
A related but more complex alternative to staining and then sorting on membrane levels of product involves the use of product entrapment approaches such as the gel microdrop (GMD) technique or matrix-based secretion assays. In such approaches, secreted antibody is retained by either cross linkage to the cell membrane or within gel microdrops, or immobilised on an artificial matrix on the cell surface prior to FACS sorting with anti-product antibody on levels of fluorescence.
For a recent review on cytometry based cell sorting methods discussing both indirect selection approaches (i.e. via use of a marker) and direct selection approaches (i.e., via labelling of desired product associated with the cells) see Carroll and Al-Rubeai 2004 (Expert Opin Biol Ther 4: 1821-9) and Browne and Al-Rubeai 2007 (Trends Biotech, 25(9), 425-32).
However, whilst both direct and indirect labelling methods as described above are now proven successful, none to date are ideal for use in selecting high producing cell lines suitable for the manufacture of biopharmaceuticals. This is because, if the indirect approach is employed, one selects primarily for cells producing high marker levels as discussed above. Alternatively, all the direct selection methods to date employ animal derived anti-product antibodies and supporting reagents (e.g. foetal calf serum (FCS) or bovine serum albumin (BSA)), which are undesirable in the development and manufacture of biopharmaceuticals. Such animal reagents are also regularly employed to support cell viability during harsh flow sorting and plating procedures. This will again increase the risk of exposure to adventitious agents for any cell line thereby generated. Additionally, animal derived reagents such as serum or BSA are typically used to block non-specific binding prior to incubation of cells with the desired anti-product binding reagent such as anti-serum.
Recently, Applebaum et al. (US 2010/0028904), described a method to screen and select for high expressing cells by plating the cells in methylcellulose (semi-solid media) containing fluorescent Protein A/G to detect product expression. However, considerable challenges still remain with such methodology. Significantly, the fluorescent Protein A/G does not necessarily bind the protein of interest on the cell surface but rather the secreted protein around the cell (resulting in a "halo" around the cell mass). Indeed, Protein A primarily binds to antibody and Fc fusion proteins in the constant domain and it remains unknown if the Protein A binding epitopes of any such targets are presented and available for binding on the cell membrane prior to product dissociation and full secretion from the cell. Thus, this method largely relies on labelling of the Fc-protein free of the cell, suspended in the semi-solid medium. The result is that the method cannot guarantee clonality of the lines picked. In addition, the conditions for the growth of cells in semi-solid media and the amount of fluorescent Protein A/G to be used may need to be established each time the method is used. The selection of cells from semi solid medium is also time consuming, as a period of time (normally at least seven days) is required to enable the cell to secrete sufficient quantities of product into the medium surrounding the cells to enable detection.
Moreover, the levels of target binding and thereby levels of fluorescence achievable are considerably reduced due to the lower avidity of Protein A, relative to higher avidity antiserum (such as a non-human anti-product antiserum). For these reasons Protein A is typically only employed as a secondary labelling reagent in conjunction with higher avidity primary reagents.
There is a desire in the art for improved cell selection methods.

Method for selecting high producing cell lines