The present invention uses the principle that phosphomolybdate binds to hydrophobic surfaces to isolate the phosphomolybdate complex from other phosphate-containing molecules and further uses the SPA concept to bring a radiolabeled phosphomolybdate complex in close contact with a scintillant for measurement by scintillation counting. Generally, the present invention provides an assay for detecting and measuring the amount of orthophosphate (Pi) in an aqueous reaction mixture, wherein the amount of Pi released is separated from the reaction mixture by: adding a solution of molybdate to the reaction mixture to form a phosphomolybdate complex; and contacting the phosphomolybdate complex with a hydrophobic surface, wherein the surface is capable of being separated from the aqueous reaction mixture to allow measurement of the Pi. Particularly, this invention provides an assay for measuring the ATPase activity of enzymes, more particularly, the HPV E1 helicase.

The present invention relates to a new ATPase assay. This invention particularly relates to a new method for the detection and measurement of the amount of orthophosphate released by hydrolysis of ATP or any other phosphate containing molecule. More particularly, this invention relates to a new method for the measurement of the ATPase activity of the E1 helicase enzyme from the human papilloma virus (HPV).
HPV-associated disease
The human papillomaviruses (HPVS) are small DNA viruses that infect cells of the cutaneous and mucosal epidermis. Over 80 different HPV genotypes have been characterized. Some types, such as HPV-1, -2, -3, -4 and -10, cause cutaneous lesions known as warts or papillomas. These growths are benign and self-limiting, and are found on the hands and feet of 7-10% of the general population. Of greater medical concern are those HPV types that infect the anogenital tract. These genotypes are designated as either xe2x80x9clow-riskxe2x80x9d or xe2x80x9chigh-riskxe2x80x9d based on their correlation with malignant progression.
So-called low-risk HPVs are associated with genital warts, or condyloma acuminata. For instance, HPV types 6 and 11 are found in more than 90% of benign genital lesions, and very rarely associated with malignant transformation. However, they nonetheless represent a serious public health problem. Approximately 1% of sexually active adults in the U.S.A. have visible genital warts, but in many more cases the infection is sub-clinical. In fact, an estimated further 15% of people aged 15-49 display molecular evidence of HPV infection, in the form of viral DNA detectable by polymerase chain reaction (PCR) assay. Indeed, HPV is ranked as the most common sexually-transmitted viral agent in the U.S.A. and U.K., and its incidence is increasing steadily.
Infection with high-risk HPV types such as 16,18, 31 and 33, has been strongly linked to the development of anogenital malignancies, most notably cervical cancer. In fact, HPV types 16 and 18, while rarely found in benign genital lesions, are detectable in about 70% of all invasive carcinomas of the cervix. The link between HPV and anogenital cancer is well documentedxe2x80x94recent studies have found that almost 90% of cervical carcinomas contain HPV DNA.
In spite of the pervasiveness of HPV infection and its possibly life-threatening consequences, no virus-specific inhibitor has yet been described. Antiviral drug discovery for HPV has proven quite difficult thus far as a result of difficulties encountered in propagating the virus in the laboratory.
All current therapies for HPV infection rely on the non-specific destruction or removal of infected tissue. Accepted surgical procedures include the use of dry ice, liquid nitrogen, CO2 laser therapy, electrocautery or local excision. Various cytotoxic agents are also used to destroy tissue, such as salicylic acid, tricholoroacetic acid, podophyllin, colchicine, bleomycin and cantharidine.
While the risk of cancer makes these procedures the most prudent for the treatment of high-risk HPVs, less invasive treatments are being sought to manage the low-risk genotypes. Compounds that stimulate the immune system have been investigated with the goal of reproducing the spontaneous regression often seen with benign lesions. Imiquimod, such an immune response modifier, has recently passed clinical trials and been approved for treatment of HPV-associated genital warts.
Patients with genital warts often experience high recurrence ratesxe2x80x94usually 30-90%xe2x80x94following non-specific treatments such as surgery. Such poor efficiency is a result of the incomplete elimination of HPV DNA, or the presence of virus in normal-appearing tissue adjacent to the papilloma. Obviously, there is a substantial need for an effective, virus-specific therapy for HPV infection, which has thus far gone unmet.
Semi-conservative DNA replication is an intricate process mediated by many enzymes and accessory proteins. Helicases are enzymes that function during DNA replication, catalyzing the unwinding of duplex DNA ahead of the replication fork. They are very common in prokaryotic and eukaryotic cells, as well as most viruses. The exact mechanism by which helicases convert the binding and hydrolysis of ATP into mechanical energy to power the unwinding of DNA and their own simultaneous motion along the nucleic acid stand is still not completely understood.
The 72 kDa HPV E1 protein has been classified as a member of helicase superfamily III along with the T antigen of Simian Virus 40 (SV40 TAg), with which it is structurally and functionally homologous. E1 and Tag belong to a noteworthy subgroup of viral DNA helicases which have the ability to recognize and bind specific DNA sequences at the viral origin of replication (ori). Also, while most DNA helicases require a region of single-stranded DNA for entry, these proteins can initiate unwinding from completely double-stranded DNA, provided it contains an ori.
Human papillomaviruses contain approximately 8 kb of double-stranded circular DNA. In the basal cells of the epidermis, the genome is replicated and maintained extra-chromosomally at a steady-state level of about 20-100 copies per cell. High-level amplification of the genome only occurs once the cell has terminally differentiated and migrated to the upper layers of the epithelium.
In a cell-free DNA replication system, the E1 protein can direct origin-specific DNA replication by itself at sufficient concentrations, when provided with the full complement of host replication proteins including the DNA polymerase a primase enzyme. However, replication is greatly stimulated by the viral E2 protein, and at limiting concentrations of E1 the in vitro replication becomes completely E2-dependent. This is a consequence of E1 having a relatively low affinity for its DNA binding site. E2 helps to localize E1 to the origin by acting as an accessory protein . The E1 and E2 binding sites at the viral ori are in close proximity, falling within about 100 bp of each other. The carboxy terminus of E2 binds its palindromic site on DNA, while the amino terminus binds E1, thus bringing E1 to its binding site.
Recently, pharmaceutical companies have been able to substantially expand and accelerate their antiviral compound screening programs as a consequence of advances in molecular biology. Viruses are now routinely examined at the molecular level to find specific inhibitors of virus-encoded gene products.
For several viruses, enzymes such as polymerases, kinases and proteases have been targets for inhibition. In contrast, of the approximately 8 distinct proteins encoded by the HPV genome, the E1 helicase is the only one with enzymatic activity (Fields et a., 1996, Fields Virology, 3rd Ed. Lippincott-Raven, Philadelphia, Chap. 65 and refs. therein). E1 displays or-specific DNA-binding activity, E2-binding activity, ATPase activity, and DNA helicase activityxe2x80x94all of which can be assayed independently for potential inhibitors. In addition, it is the most highly conserved of all papillomavirus proteins, so an inhibitor of E1 would likely be effective against multiple HPV types.
High throughput screens are known that allow the discovery of inhibitors of the helicase activity of E1 (WO 99/157283, Nov. 11, 1999). Even though ATP is needed to drive E1 helicase activity and is included in the reaction, this helicase assay cannot be used to identify competitive inhibitors of E1 ATPase function. This is a direct result of very low Km of the ATPase, for example approximately 10 xcexcM for HPV-11 E1, and the fact that the helicase assay is routinely run with 300 xcexcm-1 mM ATP). A more sensitive assay must be developed if the ATP binding site of E1 is to be targeted for inhibition.
Helicase activity is virtually always associated with nucleoside triphosphatase activity (Matson et al., Ann. Rev. Biochem., 1990, 59, 289). Enzymatic ATP hydrolysis has been measured by a variety of methods, including colorimetric reactions; in all cases, enzymatic reactions are performed according to enzyme-specific protocols where reaction conditions are not dependent on the detection procedure (except for the inclusion of radiolabeled ATP). The detection procedure differs for the different assays in the following ways:
TLC:
The inclusion of [xcex1-33P] or [xcex3-33P] ATP in the substrate for an ATPase reaction results in the release of radiolabeled phosphate or ADP. Because of their different polarity, [33P]-labeled ATP, ADP and phosphate can also be separated by thin layer chromatography (Bronnikov et al., Anal. Biochem., 1983, 131, 69) in a running solvent (e.g. lithium chloride/formic acid). The two species migrate at different distances on a TLC plate based on their relative affinities for the polar mobile phase and non-polar solid phase. Results are analyzed by scintillation counting or Phosphorlmager analysis.
Although the TLC assay for quantification of released phosphate produces accurate data for ATPase activity and inhibition, it is unsuited for the mass-screening of potential inhibitors. The spotting and running of large numbers of TLC plates is time-consuming and labor-intensive. A method that lends itself to 96-well plate format and rapid quantification is needed if an ATPase assay is to be implemented in HTS format.
Charcoal:
ATP binds to charcoal but orthophosphate does not (Zimmerman et al. J. Biol. Chem. 1961, 236 (5), 1480). Thus if a reaction is run using xcex3-labeled ATP and charcoal is added, the starting material is adsorbed, but the product remains in solution. One can run this as a 96-well plate assay by filtering solutions through charcoal-containing filter plates, and counting the flow-through. This is not likely to be highly reproducible, and is not amenable to robotic screening.
Coupled-enzyme Assays:
There are a number of related procedures in which another reaction is carried out on the phosphate product by a second enzyme (Rieger et al., 1997, Anal. Biochem. 246, 86 and refs. contained therein). These assays are very useful for kinetic studies, because absorbance change is generated continuously over the course of the assay, so that the reaction course can be monitored without removing aliquots as necessary for the other methods above (the distinction between continuous and stop-time assays). These methods are not significantly more sensitive than the molybdate assay (below) however, and screening results would be further complicated by the possibility of false positives being inhibitors of the coupling enzyme.
Molybdate:
Ammonium molybdate forms a complex only with phosphate to form phosphomolybdate. Pyrophosphate, nucleotide triphosphates, or other phosphate-containing molecules resulting from the reaction do not interact with molybdenum oxides. Most of the colorimetric reactions are based the formation of a complex between phosphate and the molybdate ion in acid solution, followed by reduction or binding to dyes that form colored complexes. Many variations to these techniques have been introduced with the goal of increasing sensitivity and color stability, and decreasing the amount of spontaneous ATP hydrolysis that occurs during the color-developing incubation (Gonzalez-Romo et al., Anal. Biochem. 1992, 200, 235). For instance, the phosphomolybdate complex can be reduced by ascorbic acid to generate a blue molybdenum chromogen with maximum absorbance at 700 nm (Hergenrother et al., Anal. Biochem. 1997, 251, 45). Another method is based on the formation of a brilliant green complex with malachite green in an acid medium, which has a maximum absorbance at 650 nm (Moslen et al., Anal. Biochem. 1983, 131, 69).
In fact, the malachite green assay was previously evaluated as a potential test for the ATPase activity of E1, but was found to be unsuitable because it could not accurately detect concentrations of phosphate lower than 25 xcexcM. This presented a problem, because detection of competitive inhibitors is optimal at substrate concentrations below the Km of an enzyme. As previously mentioned, the Km (ATP) of the HPV-11 E1 ATPase has been shown to be about 10 xcexcM, so the E1 ATPase reaction is routinely carried out at around 1-10 xcexcM ATP. In addition, substrate consumption in an inhibition experiment is kept below 30%, so that substrate concentration remains essentially constant over the time of the reaction. The result is that 3 xcexcM is the maximum concentration of phosphate that is releasedxe2x80x94well below the 25 xcexcM detection limit of the malachite green assay.
All these colorimetric ATPase assays require a minimum ATP concentration of several hundred micromolar. The value of Km(ATP) for HPV-11 E1 being approximately 10 xcexcM (measured in the absence of DNA), thus to effectively screen for competitive inhibitors of E1 ATPase activity, one should perform assays using [ATP]xe2x89xa610 xcexcM.
Adsorption of Phosphomolybdate on Solid Support:
Phosphomolybdate is a large heteropolymolybdate, with a stoichiometry of [PMo12O40]3xe2x88x92. Because of its relatively low charge, it can be extracted from aqueous solution into organic solvents or adsorbed onto a hydrophobic surface such as Sephadex beads or nitrocellulose filters. Ohnishi et al. (J. Solid-Phase Biochem. 1976, 1(4), 287) and Ohnishi (Anal. Biochem. 1978, 86, 201) disclose a method for isolating the phosphomolybdate complex from solution by affinity chromatography on polyvinyl polypyrrolidone (PVPP) column. PVPP acts as a catalyst for the complexing reaction between PO4 and molybdenum and thereby selectively adsorbs the complex over other phosphate-containing molecules. Phosphate may be radioactively labeled and eluted from the column for counting of radioactivity. This method is limited by the fact that the labeled phosphate needs to be separated from the reaction mixture before counting. There remains a need for a robust method for phosphate determination that is amenable to a high throughput format.
Yoshimura et al. (Anal. Biochem. 1986, 58, 591) disclose a colorimetric micro-determination of molybdenum-blue by adsorbing the complex on Sephadex gel-phase. This procedure requires reduction of the complex prior to the adsorption and measures the phosphate concentration by direct absortiometry of the heteropoly acid concentrated in the gel phase. This procedure requires separation of the gel beads from the supernatant prior to measurement by colorimetry. Although this colorimetric method allows for detection of low concentrations of phosphate, it remains unsuitable for automation.
Scintillation Proximity Assay:
Hart et al. (Molec. Immunol. 1979, 16, 265) and Hart et al. (J. Nucl. Med. 1979, 20,1062) disclose a new method for immunoassay called xe2x80x9cscintillation proximity assayxe2x80x9d. This technology used scintillant latex particles coated with a ligand that specifically binds an organic reactant being investigated. All further applications of this technology with hydrophobic beads has relied on providing a specific ligand coated on the beads to bind specifically to a molecule.
U.S. Pat. No. 4,568,649 discloses such beads coated with a specific ligand and specifies that the remaining active sites on the beads must be blocked prior to the assay to prevent the reactant of interest or others from binding directly to the beads rather than to the ligand. This disclosure leads away from the present invention.
Despite the wide applications of this technology since its inception, there has not been the slightest suggestion that this same technology could be used advantageously to detect radiolabeled phosphate through hydrophobic interaction with a phosphomolybdate complex. Applicant""s use of the SPA concept in the detection of ATPase activity is founded on the observation that the hydrophobic phosphomolybdate complex binds to hydrophobic surfaces, particularly to the surface of polyvinyl toluene SPA beads, whereas the charged ATP molecule does not. Applicant has used that property to separate the orthophosphate from ATP or ADP and takes advantage of the scintillant-coated beads for measurement of radioactive orthophosphate. Applicant therefore provides a robust method for detecting and measuring orthophosphate. This assay is amenable to large scale and provides reproducible results for detection of Pi in the low nanomolar range. This method is also suitable for kinetic analysis not easily performed by prior art assays.
The present invention uses the principle that phosphomolybdate binds to hydrophobic surfaces to isolate the phosphomolybdate complex from other phosphate-containing molecules and further uses the SPA concept to bring a radiolabeled phosphomolybdate complex in close contact with a scintillant for measurement by scintillation counting.
In a first embodiment, the present invention provides a method for detecting and measuring radiolabeled orthophosphate (Pi) in an aqueous reaction mixture, comprising the steps of:
a. adding a solution of molybdate to said reaction mixture under acidic conditions to form a phosphomolybdate complex; and
b. contacting said phosphomolybdate complex with a scintillant hydrophobic surface;
whereby binding of phosphomolybdate to the surface provides enough proximity for the radiolabeled phosphate to induce measurable scintillation of the scintillant correlating the amount of orthophosphate.
In a second embodiment, the present invention consists of a method for determining ATPase activity, comprising the steps of:
a. mixing radiolabeled [xcex3-33P]ATP with an ATP hydrolyzing enzyme;
b. incubating reaction mixture a sufficient time to afford orthophosphate to be released from hydrolysis;
c. adding a solution of molybdate to said reaction mixture to form a phosphomolybdate complex;
d. contacting said phosphomolybdate complex with a scintillant hydrophobic surface; and
e. measuring scintillation of said scintillant as a means to calculate the amount of said orthophosphate.
Optionally, the method also comprises: step f) adding a solution of CsCl to said reaction mixture prior to counting. Further optionally, the method comprises step g) adding a solution of citric acid to said CsCl-containing mixture prior to counting.
In a third embodiment, the present invention consists of an assay for screening inhibitors of a phosphate-hydrolyzing enzyme activity comprising the steps of: carrying out steps a to e (and optionally steps f and g) according to the method above, in the presence and absence of a candidate inhibitor; and comparing the amounts of orthophosphate in each case to calculate the levels of inhibition.
Commercially available SPA beads are microscopic beads impregnated with scintillant, and are available with a variety of molecules attached to their surface (e.g. streptavidin, glutathione, protein A). Polyvinyl toluene (PVT) SPA beads have relatively hydrophobic surfaces, and are capable of selectively adsorbing phosphomolybdate from reaction mixtures in the presence of excess ATP. Although SPA beads are treated to make them less hydrophobic, the hydrophobic interaction may be enhanced by high concentrations of cesium chloride commonly used to float beads in SPA protocols. In an aqueous medium, weak xcex2-particle emitters such as [33P] need to be in close physical proximity to scintillant molecules to cause them to emit lightxe2x80x94otherwise their energy is dissipated and lost in the solvent. Thus, [33P]-labeled phosphate complexed with molybdate and bound to the bead surface causes activation of the scintillant, whereas [33P]-labeled ATP free in solution does not. The light emitted by a sample is measured by a xcex2 scintillation counter and is proportional to the amount of phosphate present. SPA beads are commercially available and are presently treated by the company with a polyhydroxy film to be less hydrophobic. It is however contemplated by the Applicant that non-treated SPA beads may be particularly suitable for this particular assay.
The method and assays of the present invention are useful not only for the HPV E1 helicase, but for any ATPase, NTPase, or any enzyme which generates orthophosphate as a product, especially if the substrate Km is in the nanomolar to low micromolar range.
Particularly, the assay of the present invention is useful for determining the ATPase activity of various ATP hydrolyzing enzymes where it is desirable to run the assay at nM to low xcexcM concentrations of substrate. Such enzymes include (without being restricted thereto): helicases (e.g. from other viruses such as HPV, HSV, CMV, HCV), other infectious agents (e.g. bacteria), or cellular helicases; other energy transducing ATPases (such as for example myosins, dyneins, kinesins), ion transport ATPases, or chaperoning; other nucleotide phosphate-hydrolyzing enzymes (e.g. G proteins); protein or small molecule phosphatases; or inorganic pyrophosphatases.
In a fourth embodiment, the present invention comprises a kit for measuring radiolabeled orthophosphate in an aqueous solution, said kit comprising:
a. a solution of molybdate; and
b. a scintillant hydrophobic surface;
wherein said molybdate solution is added to said aqueous solution to form a phosphomolybdate complex, said complex being captured by said hydrophobic surface to induce measurable scintillation thereto.
A number of documents are cited in the present application. The content of such citations is incorporated herein by reference.
Other objects, advantages and features of the present invention will become more apparent upon reading of the following non-restrictive description of the preferred embodiments with reference to the accompanying drawings which is exemplary and should not be interpreted as limiting the scope of the invention.


A touch screen for use with an organic light emitting diode (OLED) display, includes: a substrate having a top side and a bottom side; a plurality of touch screen elements located on the top side of substrate; and a polarizing element for reducing glare and improving contrast of the OLED display, wherein the polarizing element is an integral part of the touch screen.

Emissive flat-panel display devices are widely used in conjunction with computing devices and in particular with portable devices. These displays are often used in portable devices or in public areas where the use of a keyboard in association with the computer used to drive the display is impractical. In these situations, a touch screen interface to the display is often employed.
A touch screen is a device placed over or above a display which provides a signal when the screen is mechanically touched. There are a variety of detection methods used including capacitive, surface acoustic wave, infrared, and resistive (with either four or five wires). With the exception of the infrared method, each of these methods relies on a hard substrate into or onto which various signals and detecting devices are built.
FIG. 1 shows a prior art touch screen 10. The touch screen 10 includes a transparent substrate 12. This substrate 12 is typically rigid, and is usually glass, although sometimes a flexible material, such as plastic, is used. Various additional layers of materials forming touch sensitive elements 14 of the touch screen 10 are formed on top of the substrate 12. The touch sensitive elements 14 include transducers and circuitry that are necessary to detect a touch by an object, in a manner that can be used to compute the location of such a touch. A cable 16 is attached to the circuitry so that various signals may be brought onto or off of the touch screen 10. The cable 16 is connected to an external controller 18. The external controller 18 coordinates the application of various signals to the touch screen 10, and performs calculations based on responses of the touch sensitive elements to touches, in order to extract the (X, Y) coordinates of the touch.
There are three commonly used touch screen technologies that utilize this basic structure: resistive, capacitive, and surface acoustic wave (SAW). For more information on these technologies, see "Weighing in on touch technology," by Scott Smith, published in Control Solutions Magazine, May 2000.
There are three types of resistive touch screens, 4-wire, 5-wire, and 8-wire. The three types share similar structures. FIG. 2a shows a top view of a resistive touch screen 10. FIG. 2b shows a side view of the resistive touch screen 10. The touch sensitive elements 14 of the resistive touch screen 10 includes a lower circuit layer 20, a flexible spacer layer 22 containing a matrix of spacer dots 24, a flexible upper circuit layer 26, and a flexible top protective layer 28. All of these layers are transparent. The lower circuit layer 20 often comprises conductive materials deposited on the substrate 12, forming a circuit pattern.
The main difference between 4-wire, 5-wire, and 8-wire touch screens is the circuit pattern in the lower circuit layer 20 and in the upper circuit layer 26, and the means for making resistance measurements. An external controller 18 is connected to the touch screen circuitry via cable 16. Conductors in cable 16 are connected to the circuitry within the lower circuit layer 20 and the upper circuit layer 26. The external controller 18 coordinates the application of voltages to the touch screen circuit elements. When a resistive touch screen is pressed, the pressing object, whether a finger, a stylus, or some other object, deforms the top protective layer 28, the upper circuit layer 26, and the spacer layer 22, forming a conductive path at the point of the touch between the lower circuit layer 20 and the upper circuit layer 26. A voltage is formed in proportion to the relative resistances in the circuit at the point of touch, and is measured by the external controller 18 connected to the other end of the cable 16. The controller 18 then computes the (X, Y) coordinates of the point of touch. For more information on the operation of resistive touch screens, see "Touch Screen Controller Tips," Application Bulletin AB-158, Burr-Brown, Inc. (Tucson, Ariz.), April 2000, pages 1–9.
FIG. 3a shows a top view of a capacitive sensing touch screen 10. FIG. 3b shows a side view of the capacitive sensing touch screen 10. The touch sensitive elements 14 include a transparent metal oxide layer 30 formed on substrate 12. Metal contacts 32, 34, 36, and 38 are located on the metal oxide layer 30 at the corners of the touch screen 10. These metal contacts are connected by circuitry 31 to conductors in cable 16. An external controller 18 causes voltages to be applied to the metal contacts 32, 34, 36, and 38, creating a uniform electric field across the surface of the substrate 12, propagated through the transparent metal oxide layer 30. When a finger or other conductive object touches the touch screen, it capacitively couples with the screen causing a minute amount of current to flow to the point of contact, where the current flow from each corner contact is proportional to the distance from the corner to the point of contact. The controller 18 measures the current flow proportions and computes the (X, Y) coordinates of the point of touch. U.S. Pat. No. 5,650,597, issued Jul. 22, 1997 to Redmayne describes a variation on capacitive touch screen technology utilizing a technique called differential sensing.
FIG. 4a shows a top view of a surface acoustic wave (SAW) touch screen 10. FIG. 4b shows a side view of a SAW touch screen 10. The touch sensitive elements 14 include an arrangement of acoustic transducers 46 and sound wave reflectors 48 formed on the face of substrate 12. The sound wave reflectors 48 are capable of reflecting high frequency sound waves that are transmitted along the substrate surface, and are placed in patterns conducive to proper wave reflection. Four acoustic transducers 46 are formed on the substrate 12 and are used to launch and sense sound waves on the substrate surface. A cable 16 is bonded to the substrate 12, and contains conductors that connect the acoustic transducers 46 to an external controller 18. This external controller 18 applies signals to the acoustic transducers 46, causing high frequency sound waves to be emitted across the substrate 12. When an object touches the touch screen, the sound wave field is disturbed. The transducers 46 detect this disturbance, and external controller 18 uses this information to calculate the (X, Y) coordinate of the touch.
FIG. 5 shows a typical prior art organic light emitting diode OLED flat panel display 49 of the type shown in U.S. Pat. No. 5,688,551, issued Nov. 18, 1997 to Littman et al. The OLED display includes substrate 50 that provides a mechanical support for the display device. The substrate 50 is typically glass, but other materials, such as plastic, may be used. Light-emitting elements 52 include conductors 54, a hole injection layer 56, an organic light emitter 58, an electron transport layer 60, and a metal cathode layer 62. When a voltage is applied by a voltage source 64 across the light emitting elements 52 via cable 67, light 66 is emitted through the substrate 50, or through a transparent cathode layer 62.
Conventionally, when a touch screen is used with a flat panel display, the touch screen is simply placed over the flat panel display and the two are held together by a mechanical mounting means such as a frame. FIG. 6 shows such a prior art arrangement with a touch screen mounted on an OLED flat panel display. After the touch screen and the OLED display are assembled, the two substrates 12 and 50 are placed together in a frame 68. Sometimes, a narrow air gap is added between the substrates 12 and 50 by inserting a spacer 72 to prevent Newton rings.
Flat-panel displays have a problem that is also present when touch screens are used in conjunction with the displays. Ambient light incident on the front surface of either the flat panel or the touch screen is reflected from the front surface to the viewer's eyes, as is illustrated in FIG. 7 (prior art). In FIG. 7 a touch screen with components 12 and 14 are placed above a display with components 50 and 52. Light 100 is reflected from the surfaces of the components together with emitted light 101. This reflected light 100, or glare, reduces the percentage of light from the light-emitting display 101 that reaches the viewer's eyes thereby reducing the perceived brightness and effective contrast of the display. This problem is commonly dealt with by placing polarizing filter (generally circular) between the viewer and the reflective surface. FIG. 8 illustrates this with a filter 110 placed above the display and FIG. 9 with a filter 110 placed above the touch screen. However, the use of additional filters within a composite flat-panel display with a touch screen creates additional processing steps, requires additional components, and creates additional interlayer reflections which raise cost, reduce reliability, and reduce.
There is a need therefore for an improved touch screen for use with an OLED flat panel display that reduces reflections and increases contrast of the display, while containing manufacturing costs.

This patent is subject to a terminal disclaimer.

Touch screen for use with an OLED display


A method includes receiving, at a proxy server, a multicast announcement through a first network. The multicast announcement is received from a casting device. The method further includes multicasting, from the proxy server, a modified version of the announcement to a second network.

A media casting device (e.g., Chromecast®) (Chromecast is a registered trademark of Google LLC of Mountain View Calif.) is configured to access media content based on commands from a user device (e.g., a mobile phone, tablet computer, etc.) and provides the media content to a media output device (e.g., a display device, an audio output device, etc.). The casting device may be connected to the media output device and connected to a network (e.g., a WiFi® network). The casting device may announce itself to devices on the network via an Internet protocol (IP) multicast message (e.g., a multicast domain name system message) and may be controlled by any device connected to the network that receives the IP multicast message. For example, a user device connected to the network may instruct the casting device to access media content hosted by a particular provider via the Internet and to present the media content at the media output device. However, in some situations, a provider or owner of the casting device may not wish to provide access to the casting device to each device connected to a network. For example, a hotel operator may provide a guest wireless network and may provide a casting device in room 302 of a hotel, but the hotel operator may not wish to allow a guest staying in room 303 who has access to the guest wireless network to control the casting device in room 302.
To address this issue, some systems place casting devices on a separate network from user devices that control the casting devices and include a proxy server to bridge communications between the casting devices and the user devices. For example, the proxy server may receive an IP multicast message including an announcement of a casting device via a first network and may repackage the announcement in a unicast message sent to a specific user device on a second network. Unfortunately, in some implementations, software executable by the user device to interact with the casting device may not support receiving such an announcement in a unicast message. Accordingly, the user device may be unable to detect casting device announcements sent by the proxy server.

System and method for private media casting on a shared network


The present invention provides novel compounds that bind selectively to cells undergoing perturbations and alterations of the normal organization of their plasma membrane, while binding to a lesser degree to cells having membranes of normal organization, and their uses as diagnostic probes. Said compounds and methods used therein may be useful in medical practice, for applications such as diagnosis of disease and monitoring of response to therapy.

The plasma membrane (outer membrane) of intact eukaryotic cells is characterized by a highly organized structure. This high level of organization is determined, among others, by the molecular structure of the specific lipids constituting the membrane; the ratio between the various lipid species from which the membrane is composed; the distribution of the phospholipids between the outer and inner leaflets of the membrane; and by the membrane protein constituents.
While maintenance of the high level of membrane organization is fundamental to normal cell physiology, substantial perturbations and alterations of the normal organization of the cell plasma membrane (PNOM) occur in numerous physiological and pathological conditions, and are characterizing a plurality of diseases (Martin, S., et al., 1995). Such alterations and perturbations may be evident both at the morphological level (membrane blebbing observed in cells undergoing apoptosis) and at the molecular level. The scope of perturbations accompanying either cell activation, cell disease or cell death is not fully elucidated. They include, among others, scrambling and redistribution of the membrane phospholipids, with movement to the cell surface of aminophsopholipids, mainly phosphatidylserine (PS) and phosphatidylethanolamine (PE), which are normally restricted almost entirely to the inner leaflet of the membrane bilayer, and reciprocal movement of sphingomyelin (SM) and phosphatidylcholine (PC) from the outer leaflet to the inner leaflet of the membrane (Sims, P. J., et al., 2001). This redistribution is referred herein as loss of cell membrane lipid asymmetry (CMLA).
These alterations play an indispensable role in making the cell surface a catalytic platform for the assembly of several clotting factor complexes, such as the tenase and prothrombinase protein complexes (Bevers, E. M., et al., 1999). Thus, platelets undergo PNOM upon activation, and these alterations constitute an important factor in normal blood coagulation, as well as in the initiation and/or propagation of abnormal, excessive blood clotting in numerous disorders. These disorders include, among others, arterial or venous thrombosis or thrombo-embolism [e.g., cerebral stroke, myocardial infarction, deep vein thrombosis (DVT), disseminated intravascular coagulation (DIC), thrombotic thrombocytopenic purpura, etc.]; unstable atherosclerotic plaques, sickle cell disease; beta-thalassemia; anti-phospholipid antibody syndrome; among others in systemic lupus erythematosus (SLE); disorders associated with shedding of membrane microparticles, e.g., neurological dysfunction in association with cardiopulmonary bypass.
Apoptosis is another major situation in which alterations/perturbations of cell membrane take place (Bratton, D. L., et al., 1997). Apoptosis is an intrinsic program of cell self-destruction or "suicide", which is inherent in every eukaryotic cell. In response to a triggering stimulus, cells undergo a highly characteristic cascade of events of cell shrinkage, blebbing of cell membranes, chromatin condensation and fragmentation, culminating in cell conversion to clusters of membrane-bound particles (apoptotic bodies), which are thereafter engulfed by macrophages (Bursch, W., et al., 1992). PNOM is a universal phenomenon in apoptosis, it occurs early in the apoptotic cascade, probably at the point of cell commitment to the death process, and has also been shown to be an important factor in the recognition and removal of apoptotic cells by macrophages (Van den Eijnde, S. M., et al., 1997).
A strong correlation has been recently drawn between PNOM and potent procoagulant activity of apoptotic cells (Bombeli, T., et al., 1997). PNOM in apoptotic endothelial cells, such as in atherosclerotic plaques (Mallat, Z., et al., 1997), probably plays an important role in the pathogenesis of thrombotic vascular disorders. PNOM is also a feature of inflammatory cells (i.e., lymphocytes, macrophages), activated by various triggers.
Since apoptosis, thrombosis or inflammation have an important role in the majority of medical disorders, it is desirable to have tools for detection of these biological processes. Compounds for selective binding to PNOM membranes, potentially also performing subsequent entry into these cells having such PNOM membranes, may therefore serve as an important tool for detecting and targeting of cells undergoing damage or death process, especially by apoptosis, or undergoing activation. In the clinical context, detection of binding to said membranes may be useful in the diagnosis of disease, in monitoring course or progression of a disease, or in monitoring the effect of various therapeutic approaches utilized to alter disease course.

Agents for imaging and diagnostic methods using them


A computer implemented tool forecasts the spot price of electric power in a deregulated market and the amounts of power that may be traded in this market. Using generating capacities of multiple utilities, price functions, weather forecasts, and transmission variables, the computer implemented tool makes these forecasts at different delivery points, providing the decision maker with probabilistic distributions for spot prices and trading.

1. Field of the Invention
The present invention generally relates to computer implemented forecasting tools and, more particularly, to a tool for forecasting the spot-market prices of electric power and the trading transactions at different delivery points.
2. Background Description
Electricity is an essential part of our lives. If we took a moment to think of the services that would not exist if electricity were not available, we would be amazed. Almost every aspect of our modern lives involves electric power, from light bulbs and television sets to hospitals and automobile industries. Although we are used to having power whenever we need it, the processes and systems involved in delivering electricity require careful planning and sophisticated mathematical and forecasting models.
Lately, due to rising costs of energy and discrepancies in its price among different regions of the country, the legal framework surrounding the electric-power industry has changed. This change has opened the door for utilities to compete with each other and against independent suppliers regardless of their geographic location. Although this change will benefit the consumer, utilities are going to face a highly unpredictable market and will need to make tough decisions regarding power generation and delivery.
The power industry is going through deregulation. The current picture of a single utility controlling the market in a specific region will soon disappear. Instead, there will be power producers who sell their product to a power pool; and power suppliers who will buy power from this pool and in turn sell it to their customers. Although the full picture of the power industry after deregulation is not yet known, it is clear that utilities need to prepare themselves for an open market in which buying and selling power are to be considered when scheduling their generating units.
The main reason behind deregulation is to reduce the high price of electric energy. Initial steps towards deregulation were taken in 1978 with the passage of the Public Utilities Regulatory Policy Act. This act encouraged nonutility generation and required utilities to buy power from independent generators. The Energy Policy Act of 1992 took deregulation a step further by mandating open access to the transmission system for wholesalers.
Currently, electricity is sold as a service that is delivered to specified points. For example, each one of us expects to receive electric power via a meter outside the house. We pay for this service regardless of its producer or which power lines it followed. That is, an electricity bill indicates the total usage of electricity in kilowatt hours (KWH) and the service price per KWH without incorporating any other details into the pricing scheme. Deregulation is changing this picture by unbundling the electric power into generation and transmission. In the future, one will pay a production cost and a transmission fee. There will be several power suppliers from whom electric power may be purchased. Suppliers may have different pricing mechanisms. For instance, there might be a discount for using power off-peak periods or for signing a long-term contract with the supplier. Power producers will compete with each other to minimize their costs so that they can sell their product to more customers and maximize their profit.
The hope is that deregulation will result in cheaper prices and play a part in improving the economy by encouraging investments in electric utilities. The size of the electric industry is expected to grow after deregulation as was the case with the telecommunications industry. The telecommunications industry's revenue shot up from $81 billion to $170 billion within ten years of deregulation.
A pitfall of deregulation is that the load on a utility system is becoming increasingly unpredictable. The reason is that trading transactions can change the load pattern significantly. For example, some utilities may sell more than 30% of their power generation to other utilities on certain days. Demand and supply in the market are functions of volatile electricity prices which in turn depend on highly unpredictable elements such as regional weather conditions and fuel prices.
There are two components for any competitive environment: physical and commercial. In the case of electricity, the physical component already exists in the form of transmission lines and all consumers have physical access to the market. The commercial component consists of the ability of buyers and suppliers to execute trades over the physical network. One should also ensure that anyone who is interested in joining this market has non-discriminatory access to the physical network. In this environment, suppliers and consumers have the freedom to contract with each other under negotiated terms and conditions. To ensure the delivery of the power traded, they need a mechanism to ensure the physical delivery of the electricity. Also, they may need to rely on a spot market to buy or sell additional electricity.
Although the new environment encourages competition, power transmission will remain regulated for the time being in order to maintain a reliable system. The transmission lines in each state or region will be controlled by an independent entity called Independent System Operator or ISO. One of the ISO responsibilities is to settle financially with the parties involved in transmitting electric power. The transmission cost depends on the proximity of the supplier and the congestion of the transmission lines as well as other operational factors. To maintain a reliable system, ISO announces, twenty-four hours in advance, the load forecast on the system and asks interested suppliers to submit bids; i.e., amount of power to be delivered at each point and pricing information. The load forecast is given for each delivery point within the physical system.
Bids are submitted to the Power Exchange or PX which then holds an auction to determine which suppliers to buy power from. For each delivery point, the PX chooses the least expensive source of power, then the second least expensive, and so on. The process is repeated until the forecasted load on the system is met. Note that the previous process ensures that the customers' need for electricity is satisfied at a minimal cost. The bidding cost of the last supplier chosen in the bidding process is the spot-market price for power at this delivery point. The PX performs this process for each delivery point in the system and at each hour of the day.
After agreeing on the production schedule, the ISO studies the schedule to make sure that it is feasible; i.e., it does not exceed the capacity of the transmission lines. Transmission charges are a function of the congestion of the power lines. These charges are calculated by ISO and billed to the different parties involved in trades.
Note that suppliers who submit a bid with a high price may end up not selling any of their production. On the other hand, selling power at a low price may not create enough revenue for a generator. Given that no one knows in advance the amount of power that competitors may bid for, the electric-power market will become more uncertain and risky. The hope is that competition will force utilities to minimize their production costs which will, in turn, benefit consumers and the economy in general. The previous model also encourages individuals to invest money in the electric-power market. For instance, if the charges across a certain power line are relatively high due to congestion, an investor could build an alternative power line in the hope of benefitting from the high-traffic in that region. The result, of course, is a reduction in the transmission cost in that region and an increase in the reliability of the system.

International Business Machines Corporation


In a belt drive continuously-variable transmission control apparatus, a line pressure control section controls a line pressure to be supplied to a shift control valve for controlling a fluid pressure to a primary pulley, and a secondary pulley, in accordance with an estimated input torque to the continuously-variable transmission, and an input torque estimating section to determine the estimated input torque in accordance with a speed ratio and a torque ratio of the torque converter. The input torque estimating section includes a speed ratio monitoring subsection to examine whether the speed ratio is in an increasing state; and a torque ratio setting subsection to decrease the torque ratio when the speed ratio is in the increasing state.

The present invention relates to control apparatus and/or method for a belt drive continuously-variable transmission connected with a torque converter.
A continuously-variable transmission (CVT) of one type used for a vehicle is arranged to receive a torque from an engine through a torque converter, and to vary a transmission ratio or gear ratio continuously with primary and secondary pulleys connected by a V belt with each other. A controller for such a continuously-variable transmission calculates a target transmission ratio in accordance with a vehicle speed and a driver's accelerator input or accelerator opening degree corresponding to an accelerator depression degree, and controls the actual transmission ratio toward the target transmission ratio by controlling a fluid pressure to the primary pulley to vary contact widths of the V belt with the primary and secondary pulleys.
The controller of such a system sets a line pressure in accordance with an input torque to the continuously-variable transmission, and controls the contact frictional forces of the V belt with the pulleys with the line pressure. The line pressure, if too low with respect to the input torque, could cause slippage between the V belt and pulleys. An increase of the line pressure too high could increase a drive loss in an oil pump for producing the line pressure.
Because of the interposition of a torque converter between an engine and a continuously-variable transmission, it is not possible to sense the input torque to the transmission directly. Therefore, a control system disclosed in a Japanese Patent Application Publication H01(1989)-206155 is configured to measure a torque converter input revolution speed (=engine speed Ne) and a torque converter output speed (=primary pulley speed Np); to calculate a torque converter speed ratio (=output speed/input speed) e from the measured torque converter input and output speeds; and to estimate an input torque Tat to the continuously-variable transmission by using a speed ratio versus torque ratio map representing a relationship between the speed ratio e and a torque ratio τ of the torque converter.

Control for belt-type continuously-variable transmission


An electronic apparatus is housed in a dual housing structure that includes an inner case housing electronics and an outer case surrounding the inner case. The inner and outer cases have respective intake openings and are spaced from each other by a sufficient distance such that an intake chamber is defined therebetween. A fan unit is provided, for discharging exhaust air from within the apparatus, and a silencer is provided, for silencing the exhaust air discharged via the fan unit. Mounting portions are formed on the front and rear surfaces of the fan unit and are attached to a fan case via gel-state shock absorbers.

The present invention relates to ventilating structures for use in electronic apparatus such as video projectors. The present invention also relates to ventilating structures for use in video projectors having a projecting lens in their front end section. The present invention also relates to structures for mounting a ventilating fan unit for use in electronic apparatus such as video projectors.
In homes and offices, video projectors are being popularly used for projecting video images on a screen. Generally, each of the video projectors includes a built-in light source of great light quantity for projecting video images on a large screen. For example, the light source is in the form of an incandescent lamp that consumes electric power in the order of 150 watts. Electronic circuitry for processing video signals in the video projector also consumes electric power more than 50 watts and thus the video projector as a whole consumes power exceeding 200 watts, so that a considerable amount of heat is generated in the interior of the video projector. Because sufficient heat dissipation is not attainable by natural ventilation, an electric fan is normally used to compulsorily introduce external air into the interior of the video projector or discharge heated air from the interior, so as to cool the electronics and lamp in the interior of the video projector.
However, because the video projector is used quite near the user or video viewer(s), the video viewer(s) would be significantly disturbed by great noise produced by the ventilation operations. Further, heated air discharged from the interior of the video projector would greatly displease and disturb the video viewer(s). Therefore, it has been conventional to support the fan unit at a plurality of corners thereof by means of supporting members each made of a rubber or other resilient material, in order to absorb vibrations of the fan unit utilizing the resiliency of the supporting members. However, because characteristics of the rubber supporting members tend to be greatly varied by temperature changes, the resiliency of the supporting members would be weakened by the heated exhaust air so that the vibrations of the fan unit are undesirably transmitted to the outer case of the video projector. Further, with the fan unit thus supported at its corners, horizontal vibrations of the fan unit can not be sufficiently absorbed.

Ventilating structure and mounting structure for electronic apparatus


A method and apparatus are provided for synchronizing over-the-air time division duplexing communication within a defined geographical coverage area (201) of a communication system (200) that provides at least cordless radiotelephone operation between a plurality of portable radiotelephone transceivers and a plurality of telepoint base stations (202, 204, 206) geographically located within the coverage area (201). The communication system (200) transmits over-the-air a synchronization timing signal (203) including timing information corresponding to a transmit-and-receive duty cycle timing for time division duplexing communication. At least one telepoint base station (204, 206) within the coverage area (201) receives the synchronization timing signal (203). The at least one telepoint base station (204, 206) synchronizes its over-the-air time division duplexing communication transmit-and-receive duty cycle timing to the timing information.

A city-wide telepoint system based on second generation cordless telephony (CT-2) technology provides service within small isolated "islands of coverage", each defined by a limited radio coverage range provided by one or more stationary communication units, e.g., base units or base stations, located therein. Cordless telephone handset units (CT handsets) are portable communication transceiver units, e.g., portable radiotelephone transceivers, that can access the public switched telephone network (PSTN) via any accessible base unit within communication range. Each base unit typically can handle one or more independent communications with one or more CT handsets, respectively, over a limited number of adjacent communication channels. A public telephone booth, or base unit, can support up to twelve to sixteen simultaneous conversations at the same location.
Each independent communication between a CT handset and a base unit utilizes full duplex burst transmission communication over a single channel. The base unit transmits a burst of information for a predetermined time interval, e.g., for one millisecond, while the CT handset receives the transmitted information. Then, for the next predetermined time interval, e.g., for the next millisecond, the CT handset transmits its burst of information and the base unit receives the transmitted information. This pulsed transmission exchange of information allows full duplex communication, e.g., a telephone conversation, over a single radio frequency (RF) channel.
Although the CT-2 protocol provides synchronization of the exchange of information between a base unit and a CT handset, i.e., one transmits while the other receives, multiple communications between "nearby" base units and CT handsets may not be synchronized with each other. Due to a limited number of available communication channels, some of the communications may be in very close or adjacent channels. Unsynchronized transmits and receives between two or more very close or adjacent communication channels can result in substantial interference between the respective communications because of the limited adjacent channel selectivity of the communication units and the wide band technology utilized in the front end of the transceivers, in both the base units and the CT handsets. Depending on how far the channels are apart, this interference can destroy the conversations, or it can introduce spurious "clicks" and "pops".
One approach to synchronize the time division duplexing communications between the multiple base units and CT handsets has been to interconnect the base units with wire and provide a 500 Hz synchronization signal, e.g., a 2 millisecond duty cycle square-wave signal, therebetween. Typically, a "master" base unit has supplied the synchronization timing signal to all the "slave" base units in a defined coverage area. In this way, all the base units would "burst" transmit at the same time, and then receive at the same time. The CT handsets, being synchronized by the CT-2 protocol with their respective base units, would likewise receive when the base units were transmitting and would transmit when the base units were receiving.
Regrettably, this approach has a number of drawbacks. First, wire interconnection between all the "nearby" base units is not always possible due to competitive systems being in close proximity. Second, limitations in the logistics available in certain situations can preclude physical wire interconnection between base units. Third, the additional wiring adds to the overall system cost and complexity which is a competitive disadvantage. Consequently, due to the very competitive nature of cordless radiotelephone communication systems, such as CT-2 systems, a better solution to this problem is necessary.

Method and apparatus for synchronizing a time division duplexing communication system


A method of assigning transaction timestamps for use with a database that includes temporal data and may include non-temporal data. In the method, a lock is placed on a resource accessed by a first transaction to prevent conflicts with concurrently executing transactions. An access record of the lock mode and a timestamp of the first transaction is created for the resource accessed by the first transaction. The access record is accessed to determine whether a resource that a subsequent transaction accesses conflicts with the resource accessed by the first transaction. A timestamp lower bound or floor is identified for the subsequent transaction when the subsequent transaction accesses a resource that conflicts with the resource access of the first transaction. A timestamp is assigned to the subsequent transaction that is greater than the lower bound. The access record of a lock mode and a transaction timestamp may be created each time a resource is accessed, may be created for resources accessed after a request for CURRENT TIME is made, and/or may be made for resources accessed after an end time of a time interval defined by a request for CURRENT TIME.

Conventional database relations contain sets of records. Insertions, updates and deletions of these records occur over time. In many applications, such as financial, banking, insurance, and medical applications it is desirable to maintain relations that contain not only the current set of records, but also a set of records that was current at any given past time. These relations are maintained in a form of a temporal database called a transaction-time database. Such a database supports queries of the form "give an answer AS OF some time in the past." In order to answer queries this type, the database needs to keep track of when changes occur in the database. This can be done by keeping track of the time at which transactions update individual records by timestamping the records. Each record version contains not only the record identification, but the timestamp of the transaction that caused the update that produced the version in question. "AS OF" queries for a time t are satisfied by searching for the versions of records with timestamps that are the largest timestamp for the record that is less than or equal to time t.
One existing approach to choosing timestamps is to delay timestamp choice until commit time. Using this approach, the time of commit can be used as the timestamp for the committing transaction. Since the commit order is consistent with transaction serialization order, the timestamp order will likewise be consistent with a serialization. One drawback of commit time timestamping is that commit time timestamping does not support transactions that request CURRENT TIME. This is because requests for CURRENT TIME can require that a timestamp be assigned that is earlier than commit time.
One solution that supports CURRENT TIME requests is disclosed in U.S. patent application Ser. No. 09/939,180 (hereinafter the '180 application), filed on Aug. 24, 2001, invented by David Lomet, assigned to the assignee of the present invention, and is incorporated herein by reference in its entirety. In the method disclosed by the '180 application, timestamps of data accessed during transaction execution are used to determine a lower bound on when a transaction could commit. An upper bound was derived from the CURRENT TIME request. So long as the interval between the lower bound and the upper bound is non-vacuous, the transaction could be committed and assigned a timestamp in the interval.
The solution disclosed by the '180 application is suited for the case where all data exists within a transaction time database. The time of last write for a record is stored as a timestamp in the record itself. This timestamp serves to identify the version of a record to be returned in a query that asks for data as of some particular time. The timestamp in the record enables the system to ensure that write-write and write-read conflicts were correctly reflected in the order of the timestamps, by requiring that the current transaction have a timestamp greater than the record's timestamp.
The '180 application also proposes keeping track of the last time that a record is read so that timestamps can be ordered consistent with read-write conflicts. The '180 application proposed a "read-timestamp table" (RTT) for this purpose. The '180 application suggested that the RTT did not have to retain information about every record, but could identify record classes by means of a hash function, used to index the table.
Existing solutions do not deal with situations where not all data resides in a transaction-time database. A solution is needed for timestamping that can work when ordinary data exists, and the ordinary data may or may not be accessed with the transaction time database data in the same transaction. Prior timestamping techniques also do not enforce timestamp order when locking detects phantoms that would result were a record to be written into ranges accessed by range queries. Prior timestamping techniques assign timestamps to individual records. However, assigning timestamps to individual records does not prevent a subsequent record from being written with a timestamp that is inconsistent with a previous range query.
There is a need for a timestamping technique that accommodates databases that include both temporal and non-temporal data. There is also a need for a timestamping technique that correctly orders timestamps when insertions conflict with range queries. There is also a need for such a timestamping technique that minimizes the overhead while correctly providing timestamps to transactions.


The present invention relates to a display device and a method of operating the display device that reduces power consumption, the method including: operating the display device in a normal driving mode to display an image on a display panel according to an image data signal; operating the display device in a sleep mode, by adjusting a clock signal and an image data signal transmitted from a set controller to of the display device to a first voltage; measuring a sleep mode time period during which the display device operates in the sleep mode; and adjusting a register value of the set controller when the measured sleep mode time period exceeds a first reference time period and maintaining the clock signal at a second voltage according to the adjusted register value as a clock-off mode.

Field
Exemplary embodiments of the present invention relate to a technique for reducing power consumption of an active matrix organic light emitting diode (AMOLED) display device in a sleep mode.
Discussion of the Background
In general, a power consumption reducing method according to a driving voltage change and a luminance change is conventionally used in order to reduce power consumption of an AMOLED display device. Particularly, most conventional methods for reducing power consumption reduce it in a driving state (normal mode) of the AMOLED display device. A limited number of methods deal with techniques for reducing the power consumption in a sleep mode thereof.
Conventionally, a deep sleep mode (ultra-low power state, ULPS) method is employed as a function for reducing the power consumption in the sleep mode state of the AMOLED display device. This method, however, has limited application fields and requires an additional resistor configuration and process to enter the deep sleep mode.
When a conventional set controller including the AMOLED display device enters the sleep mode, most power blocks and a phase-locked loop (PLL) of the set controller are turned off and only an operator and some I/O pins are limitedly used.
However, in a case of a display serial interface (DSI) through which the set controller and a display module are connected to each other, even when entering the sleep mode, the DSI is not completely turned off and a current ranging from several tens to several hundreds of microamperes (μA) is consumed in a driver IC.
As a result, when the sleep mode is maintained, necessary power is consumed in the driver IC.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.

Display device and power consumption reduction method


An example particle accelerator may include the following: a voltage source to sweep a radio frequency (RF) voltage in a cavity to accelerate particles from a plasma column, where the cavity has a magnetic field causing particles accelerated from the plasma column to move orbitally within the cavity, and where the magnetic field has flux that bows at edges of the cavity; a regenerator to provide a magnetic field bump within the cavity to thereby change successive orbits of the particles accelerated from the plasma column so that, eventually, particles output to an extraction point, where the regenerator is located at a radius in the cavity relative to the plasma column; and ferromagnetic arrangements located in the cavity proximate to the radius, where each ferromagnetic arrangement provides a magnetic field bump, and where ferromagnetic arrangements adjacent to the regenerator are separated from the regenerator by a space.

Particle therapy systems use an accelerator to generate a particle beam for treating afflictions, such as tumors. In operation, particles are accelerated in orbits inside a cavity in the presence of a magnetic field, and removed from the cavity through an extraction channel. An example of an accelerator that may be used in a particle therapy system is a synchrocyclotron.
In a synchrocyclotron, a plasma column is produced using ionized gas (e.g., hydrogen). An RF voltage is applied to extract particles from the plasma column, and a magnetic field is applied to maintain those particles in spiral orbits as they increase in energy and radius until they reach an extraction region. The RF voltage is swept across a range of frequencies to account for relativistic effects on the particles (e.g., increasing particle mass) when accelerating particles from the plasma column.

Focusing a particle beam using magnetic field flutter


A system for interconnecting electronic boards, which is intended to be incorporated into a computer cabinet, and a computer cabinet including such a system, to be used for interconnecting electronic boards in computer cabinets placed particularly in data centres or computer rooms, where the system has a front wall and a rear wall each having an external face and an internal face, the external face of the front wall including at least one front connection intended to allow the connection of an electronic board, the front connection being linked to one or more front connection cables on the side of the internal face of the front wall, where the front and rear walls are temporarily rigidly connected via the respective internal faces thereof by a fixing means to form a casing inside which the connection cables are placed.

Today, computer servers require interconnection of a large number of electronic boards, by placing them in supporting means such as computer cabinets.
Cabinets are already known that incorporate systems making it possible to interconnect electronic boards. A configuration such as that shown in FIG. 1 is generally used to interconnect these boards.
Such a system comprises an electronic motherboard 1 fixed in the bottom of the frame of the cabinet, provided with a number of connectors 6, 7, 8 allowing the connection of electronic daughterboards 2 on a first side, which are orientated in a first plane, and of electronic daughterboards 3, 4, 5 on the other side, which are orientated in a second plane perpendicular to the first plane.
However, such a system has several disadvantages, including the following disadvantages.
Firstly, the system does not make it possible to easily interconnect distant electronic boards in the cabinet, for example boards which would be connected to a motherboard placed at the top of the cabinet and boards which would be connected to a motherboard placed at the bottom of the cabinet.
Moreover, this system does not make it possible to easily interconnect a large number of daughterboards, for example over a great height, the limit being given by the maximum size of an electronic motherboard.
Furthermore, this system requires the use of another system at the interface between the interconnection system per se and the cabinet, in order to be able to fit with the geometry of the cabinet and be inserted therein.
Also, this system does not make it possible to connect boards on each side in a coplanar manner.

System for interconnecting electronic boards and computer cabinet comprising such a system


It is presented a converter cell comprising: a first terminal and a second terminal; an energy storage device connected on a first end to the second terminal; a first switch connected on a first end to the first terminal; a second switch arranged between the two terminals; and a third switch connected between a second end of the first switch and a second end of the energy storage device. A corresponding converter arm and method are also presented.

Converter cells are used in a variety of electrical applications. For example, converter cells can be used for power conversion in either direction between DC (Direct Current) and AC (Alternating Current), or DC to DC.
By using converter cells connected serially, an increased voltage rating can be achieved, e.g. to use the converter cells in high voltage applications such as for HVDC (High Voltage DC) applications. Additionally, converter cells can be connected in parallel to increase current rating.
Failure handling in converter cells is important but can also be complicated and/or expensive. There is a need to improve failure handling of converter cells.

Converter cell and associated converter arm and method for preventing undesired overcharging of energy storage device of the converter cell


Methods and systems for low complexity interference cancellation in multichannel optical transmission. Local or self-iteration is performed one or more times between an expected propagation decision feedback equalizer and a soft demapper. Following local iteration, a soft decision forward error correction decoder determines bit log-likelihood ratios, which are fed back to the expected propagation decision feedback equalizer and soft demapper for further self-iteration. Global iteration involving the decoder can also be performed one or more times before a bitstream is decoded.

In coherent optical transmission, multiple channels may be multiplexed either in the digital domain, e.g., using digital multi-band (DMB) systems, or in the optical or analog domain, e.g., using superchannels. The transmitted signal may face interference in the form of both inter-symbol interference (ISI) and inter-carrier interference (ICI) owing to filtering effects from optical filters, such as reconfigurable add-drop multiplexers (ROADMs), and frequency drift, respectively. Additionally, the spectral efficiency of the transmission may also be enhanced using spectral compression techniques, in both the time and frequency domains, all of which may lead to ISI, ICI or both.
Terabit-per-second (Tbps) data rates per carrier are contemplated for next generation fiber optical networks to accommodate increasing traffic demands. Transmitting at very high baud rates per carrier in order to achieve these data rates can be challenging due to the bandwidth limitations of opto-electronic devices. Therefore, increasing the spectral efficiency (SE) of transmission is desirable for next generation optical networks. As an alternative to using higher-order modulation formats, which may be sensitive to nonlinearities in the optical fiber medium, an alternative is to use spectrally efficient, densely packed wavelength-division multiplexing (WDM) superchannel transmission. Typically, in such an approach, the source and destination nodes for a set of sub-channels (SCs) that are grouped together to form a superchannel are the same, and they travel the same lightpath in reaching the destination node.
Typically, sub-channels employ closely spaced and non-overlapping carriers. These SCs are spaced apart according to the Nyquist criterion. However, further SE improvements are possible by allowing for controlled overlap of the SCs either in time via "faster than Nyquist" (FTN) signaling, or in frequency, or both. When both the time and frequency dimensions are used, such an approach is known as time-frequency packing (TFP). However, TFP can result in ISI and/or ICI. Moreover, additional sources of interference can also affect system performance, such as ICI due to transceiver laser drifts, and ISI stemming from the low-pass filter (LPF) nature of transmitter DACs/drivers and multiple ROADMs in a fiber link. Cancelling this interference would be desirable.

System and method for interference cancellation in optical transmission


The present invention relates to a novel structuring system comprising both xanthan gum and cross-linked polyacrylic acid polymer which combination unexpectedly has been found to provide enhanced stability for large size benefit agent droplets in an amphoteric/anionic surfactant system relative to use of either structurant alone.

Liquid cleanser compositions providing some kind of benefit agent are known in the art. Thus, for example, the use of silicones, oils and other emollients in liquid compositions for providing skin care benefit is known.
One method of enhancing the delivery of the benefit agent (e.g., vegetable oil, silicone) to the skin or hair, for example, is through the use of cationic hydrophilic polymers such as Polymer JR.RTM. from Americhol or Jagua.RTM. from Rhone Poulenc (see WO 94/03152). In this reference generally small sized silicone particles are uniformly distributed throughout the liquid cleanser.
Another way of enhancing delivery of benefit agent is utilizing larger size benefit agent particles. To suspend such particles without causing separation of the particles or oil droplets (e.g., flocculation, coalescence, creaming or breaking), however, is not an easy task.
One way of suspending larger size particles is through the use of thickeners such as xanthan gum. Xanthan gum thickeners are taught, for example, in U.S. Pat. No. 4,364,837 to Pader (see column 22, Table II, example 16); and in U.S. Pat. No. 4,788,006 to Bolich Jr.
U.S. Pat. No. 4,541,610 to Grollier (L'Oreal) teaches thickened or gelled hair conditioning compositions which use xanthan gum as thickener. All the examples appear to exemplify only a cationic surfactant as principal surfactant and there appears to be no teaching of an oil or emollient, let alone a disclosure of particle size.
Several patents also disclose the use of a cross-linked polyacrylic type polymer with silicone. U.S. Pat. No. 5,085,857 to Reid et al., for example, teaches in example 1 a Carbopol.RTM. in combination with silicone oil. There is no teaching of xanthan gum, however, and the silicone oil is an emulsion, i.e., not large sized silicone droplets (typically median particle sizes of emulsions are about 0.3 to 0.5 microns).
U.S. Pat. No. 5,344,643 to Thiel teaches shampoo compositions comprising an oily conditioning agent, (e.g., silicone), a carboxyvinyl polymer, a cationic conditioning agent and water. There is no teaching of xanthan gum.
U.S. Pat. No. 5,409,695 to Abrutyn et al. teaches a method of depositing silicone by entrapping silicone in a nontoxic hydrophobic macroporous highly x-linked polymer. There is no xanthan gum.

Liquid cleansing compositions comprising xanthan gum and cross-linked polyacrylic acid polymers for enhanced suspension of large droplet oils


A tunable receiver is disclosed including a plurality of select filters to perform an initial band selection, a variable-gain low noise amplifier (LNA) whose gain is controlled to prevent its output power level to exceed a pre-determined power threshold, a plurality of digitally-tunable tracking filters to pass signals within a selected channel and to reject signals in a corresponding image band, a second LNA to further amplify the received RF signal and to generate differential signal outputs, a down converting stage which converts the received RF signal to an IF signal while rejecting signals in the image band, an IF trap to further reject undesired signals present at the output of the down converting stage, an IF amplifier to amplify the IF signal to compensate for losses, an IF filter to provide channel select and reject undesirable signals, and a variable-gain IF amplifier to amplify the IF signal and maintain its power level within specification.

Tunable receivers used in cable television set-top boxes and in other applications receive broadband signals having many channels. It is a function of such a tunable receiver to produce the signals in a desired channel and reject the signals in the remaining channels. In rejecting the signals in the undesired channels, the tunable receiver should substantially remove all signals associated with the undesired channels so that the receiver outputs substantially the signals in the desired channel. These unwanted signals include image, harmonics, spurious, and other undesired signals.
Both single conversion and double conversion receivers are known in the prior art. In a single conversion receiver, the RF signal is directly down converted to the desired frequency range, either to an intermediate frequency (IF) or sometimes to baseband. In a double conversion receiver, two frequency conversions are used. Usually the selected channel is up shifted in frequency to a fixed frequency, and then down shifted from that frequency to a fixed IF frequency. In either case, various circuits with differing degrees of integration are known for the purpose.

Broadband single conversion tuner integrated circuits


A driving circuit has a p-channel transistor and an n-channel transistor. A power switching element is set at an on state each time the p-channel transistor sets a charging line at a conductive state in response to a leading edge of an output pulse to supply a positive charge to a gate of the element through the charging line. The element is set at an off state each time the n-channel transistor sets a discharging line at a conductive state in response to a trailing edge of the output pulse to discharge the supplied charge through the discharging line. A through current occasionally flows through the transistors set at the on state together. The driving circuit has resistors between the transistors to suppress the through current.

1. Field of the Invention
The present invention relates generally to a driving circuit which drives and controls a voltage control type power switching element so as to perform a switching operation in the power switching element by applying a voltage to a gate of the power switching element while controlling the voltage in response to an output pulse, and more particularly to a driving circuit having a first switching element, which sets a charging line at a conductive state to supply a positive or negative electric charge to the gate of the power switching element through the charging line in response to each first edge of the output pulse such as leading edge or trailing edge, and a second switching element, which sets a discharging line at a conductive state to discharge the supplied charge from the gate of the power switching element through the discharging line in response to each second edge of the output pulse.
2. Description of Related Art
Published Japanese Patent First Publication No. 2005-151700 discloses a driving circuit for a main switching element. In this circuit, the main switching element is driven in synchronization with each edge of an output pulse of a transformer. More specifically, a p-channel transistor of the driving circuit is turned on in synchronization with each leading edge of the output pulse to supply a positive electric charge to a gate of the switching element through the p-channel transistor, and an n-channel transistor of the driving circuit is turned on in synchronization with each trailing edge of the output pulse to discharge the supplied charge from the gate of the switching element through the n-channel transistor. Therefore, a positive voltage and a negative voltage can alternately be applied to the gate of the switching element, so that the driving circuit can drive the switching element so as to perform a switching operation in the switching element.
However, both of the p-channel and n-channel transistors are inevitably turned on together during an overlap period of time. Therefore, a large amount of current passes through the p-channel and n-channel transistors as a through current, so that reliability of the driving circuit is lowered.
Further, an other driving circuit has been proposed. This circuit has a first switching element, which sets a charging line at a conductive state in response to each leading edge of an output pulse generated in a transformer to supply a positive electric charge to a gate of a power switching element through the charging line, and a second switching element which sets a discharging line at a conductive state in response to each trailing edge of the output pulse to discharge the supplied charge from the gate of the power switching element. In this circuit, a through current flows through the conducting elements during an overlap period of time, in the same manner. Therefore, reliability of the driving circuit is also lowered.

Driving circuit for power switching device


An exposure apparatus for exposing a substrate to light from a light source via a reticle. The apparatus includes an optical system configured to introduce the light via the reticle to the substrate, a chamber configured to house at least a part of the optical system, a supply system configured to supply inert gas into the chamber at a variable supply flow rate, an exhaust system configured to exhaust gas from the chamber at a variable exhaust flow rate, and a controller configured to control the supply system so as to reduce the supply flow rate, and configured to control the exhaust system so as to reduce the exhaust flow rate prior to the reduction of the supply flow rate.

The present invention relates generally to a method of purging materials (interfering substances) from a chamber, and, more particularly, to a method of purging the interfering substances from an atmosphere around an optical system using an inert gas in an exposure apparatus for exposing a substrate, such as a single crystal substrate for a semiconductor device and a glass substrate for a liquid crystal display device ("LCD"). The present invention also relates to an exposure apparatus to which the purge method is applied, and a device manufacturing method that uses the exposure apparatus.
A reduction projection exposure apparatus has been conventionally employed which uses a projection optical system to project a circuit pattern formed on a mask (or a reticle) onto a wafer, etc., to transfer the circuit pattern, in manufacturing such a fine semiconductor device as a semiconductor memory and a logic circuit in photolithography technology. Recently, semiconductor integrated circuits have increasingly improved the degree of integration, and the present trend requires a nano order of fine processing. For this purpose, the exposure apparatus is using a laser with a short wavelength for an exposure light source. In addition, in order to maintain stable exposure performance, the exposure apparatus is designed to maintain high cleanability, and be used in an atmosphere that contains extremely little in impurities, such as a clean room.
However, as the exposure light source laser has a shorter wavelength, the exposure light causes the residual material in the exposure apparatus to photochemically react with oxygen (O2), and reaction products, such as (NH2) SO4, to adhere to and blur optical elements, such as a lens and a mirror, disadvantageously deteriorating the light intensity.
Therefore, the exposure apparatus, which uses a KrF excimer laser and an ArF excimer laser for a light source, adopts a method for purging the atmosphere around the optical elements arranged on the laser's optical path with the inert gas in order to prevent not only a deteriorated light intensity due to the impurities' adhesions to the optical elements, but also reduced transmittance due to the light absorption in oxygen, etc., in the atmosphere on the optical path.
For example, an exposure apparatus 500, which has an internal structure schematically shown in FIG. 11, generally includes a laser light source 100, an illumination optical system 102 for converting into light having a predetermined shape, a laser beam 100a that serves as the illumination light emitted from the laser light source 100, and a projection optical system 103 that images onto the wafer (substrate) 100W, the shaped laser beam 100a that has passed a reticle (or an original form) 100R.
The illumination optical system 102 includes plural optical elements, such as plural types of lens units 104a, 104b and 104c and mirrors 105a and 105b, and serves to irradiate the laser beam 100a onto an illumination area on the reticle 100R. The illumination optical system 102 and the projection optical system 103 are sealed in chambers 102a and 103a, respectively, to which a nitrogen supply unit 106 for supplying nitrogen gas (or inert gas) 106a is connected via nitrogen gas supply lines 109a and 109b and the mass flow controller 110a and 110b.
Gas exhaust lines 111a and 111b are connected to an exhaust port via valves 112a and 112b. In purging, with the nitrogen gas, the inside of the chamber 102a of the illumination optical system and the inside of the chamber 103a of the projection optical system, these gas exhaust lines 111a and 111b exhaust inside impurities and always maintain the insides of the chambers 102a and 103a to be clean. The "impurities", as used herein, means the residual materials in the chamber other than nitrogen gas as the purge gas, and cover oxygen, organic materials, reaction products between oxygen and the organic materials, outgas, water, etc. The outgas is emitted gas, which is gradually emitted from surfaces of respective components, such as an optical element and a barrel, housed in the chamber.
When the facilities of the exposure apparatus 500 stop, the valves 112a and 112b close so as to protect the insides of the chambers 102a and 103a from the ambient atmosphere. The chamber 102a is provided with oxygen concentration detectors 113a, 113b and 113c, and the chamber 103a is provided with an oxygen concentration detector 113d. Prior to exposure, these detectors detect the oxygen concentrations in the chambers 102a and 103a, so as to confirm whether the passage atmosphere of the laser beam 100a is sufficiently replaced with nitrogen gas and whether the exposure performance can be maintained.
The illumination optical system 102 needs exchanges of components when the performance of the optical element deteriorates due to contaminations caused by the photochemical reactions and long-term use. In addition, in order to adjust an output of the laser beam 100a (exposure light) in accordance with the exposure plan, a user may change a dimmer filter (not shown) provided to the illumination optical system 102 to another type. Therefore, the inside of the chamber 102a in the illumination optical system is often released to the air and the impurity concentration becomes frequently high.
As one maintenance called optical cleaning, the exposure apparatus 500 generates ozone by introducing oxygen into a space on the exposure optical path, and uses ozone to remove contaminants adhered on the optical elements. Even after this maintenance, the oxygen concentration sometimes becomes high in each of the chambers 102a and 103a for respective optical systems and misses the exposure condition. In this case, the exposure apparatus should inefficiently wait for the exposure for a certain time period of the nitrogen gas purge (while this standby time is called downtime) until the oxygen concentration reduces down to an exposable state.
For an effectively shortened downtime, one proposal has been already made (see, for example, Japanese Patent Application, Publication No. 6-216000). This proposal increases and decreases the flow rate of the purge gas based on the oxygen concentration in the exposure apparatus, and promptly replaces the inside of the exposure apparatus with inert gas without consuming a large amount of purge gas. FIG. 12 shows a flowchart for explaining the nitrogen purge process disclosed in Japanese Patent Application, Publication No. 6-216000.
However, the proposal in Japanese Patent Application, Publication No. 6-216000, causes a standby time period after the flow rate of the purge gas reduces. This is because the reduced flow rate of the purge gas deteriorates the exhaust performance in the chamber for housing the exposure apparatus's optical system, and causes backflow of the air outside the chamber and rapid increases of oxygen concentration and organic concentration of the material. As a result, the exposure conditions are not met temporarily.
In particular, an F2 laser for a next-generation exposure apparatus has a light absorption factor to oxygen one hundred times as large as that of the ArF laser. In order to obtain the light intensity using the F2 laser equivalent to the ArF laser, both the oxygen concentration and water concentration should be maintained to be below 10 ppm. In addition, since it is anticipated that the F2 laser is more sensitive to blurring due to organic materials than the ArF laser, it is forecasted that a slightly increased amount of oxygen and organic materials affect the exposure performance, and the downtime becomes long.
Accordingly, there is a demand for an inert-gas purge method that inexpensively reduces the impurity concentration in the atmosphere around the optical system in an exposure apparatus, and shortens the downtime. In addition, there are other demands for an exposure apparatus, a device fabrication method using the exposure apparatus, and manufactured devices, in which the exposure apparatus utilizes the above inert-gas purge method to improve the exposure performance and efficiency, and maintains high precision and high throughput.

Inert-gas purge method, exposure apparatus, device fabrication method and devices


In some embodiments, non-volatile memory (NVM) devices are formed on a silicon-on-insulator (SOI) substrate (12) by forming elevated sources and drains (56) in contact with extensions (46) within the top silicon layer (18) of the SOI substrate (12). Buried conductive regions (42) are formed within the top silicon layer (18) below the extensions (46) to mitigate floating body effects that occur when using SOI substrates. In other embodiments, NVM devices are formed using elevated sources and drains (56), extensions (46) and the buried conductive regions (42) in bulk semiconductor substrates. In any embodiment, logic devices may be formed in conjunction with NVM devices, wherein the logic and NVM devices have elevated sources and drains (56), extensions (46) and the buried conductive regions (42).

Silicon-on-insulator (SOI) technology has been developed to provide a number of advantages over bulk silicon device technologies. As is known, SOI provides improvements in speed and power consumption with respect to previous bulk silicon circuits. Some of the benefits of SOI technology are based on the reduced capacitance at various junctions within semiconductor devices. One problem with SOI technology is the floating body effect, which increases the number of holes in the channel region of the semiconductor device. This increase of holes can lead to an undesirable phenomenon known as "snap-back", which is a substantial increase in the current of the semiconductor device that can ultimately lead to destruction of the semiconductor device.
Unlike in bulk silicon, in SOI substrates the holes in the channel region cannot be dispersed through the top semiconductor layer or through a contact to the top semiconductor layer. In SOI substrates, the buried insulating layer and the source and drain regions, which extend from the top surface of the top silicon layer in the SOI substrate to the buried insulating layer in the SOI substrate, isolate the holes so that they cannot combine with electrons present in other areas of the SOI substrate. Although the floating body effect is undesirable for all semiconductor devices, it is especially problematic for nonvolatile memory (NVM) devices. For example, when trying to program an NVM device, the floating body effect inhibits controlling the bias on the body region of the NVM device, thus making the programming of the NVM device difficult.
In addition to the floating body effect, problems with trying to erase an NVM device must also be overcome when implementing an NVM device on an SOI substrate. When erasing an NVM device it is necessary to electrically contact the well in order to apply a voltage (i.e. bias the well). However, in SOI substrates the well is formed in the buried insulating layer and therefore is isolated and cannot be biased. In addition, it is desirable to contact the bottom semiconductor layer of the SOI substrate when erasing (and programming) NVM devices to apply voltages to a control gate and the bottom semiconductor substrate because applying a voltage only to the control gate undesirably increases the voltage needed. However, contacting the bottom semiconductor substrate when using an SOI substrate is only possible if a conductive region that extends from the top semiconductor layer to the bottom semiconductor layer via the buried insulating layer is formed. Forming such a conductive region severely increases the size of the NVM bit cell (i.e. the NVM device and associated circuitry).
One proposed solution for forming an NVM device on an SOI substrate is a DiNOR (Divided bit line NOR) device, which extends either the source or drain region farther underneath the channel region compared to the corresponding source or drain region, respectively. Due to the asymmetry of the source and drain regions, certain low power operation schemes such as uniform channel programming or hot carrier injection (HCI) cannot be performed effectively on the DiNOR device. In addition, the DiNOR device cannot easily be scaled because as the channel region of the NVM device shrinks the source and drain regions are brought closer together, resulting in severe short channel effects. Therefore, a need exists for a scalable NVM device formed on an SOI substrate that can be erased and programmed under low power operation schemes and is scalable.
Skilled artisans appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help improve the understanding of the embodiments of the present invention.

Method of forming a semiconductor device in a semiconductor layer and structure thereof