The present invention provides methods for simultaneously assessing microbial phosphoglucose isomerase, ketol-isomerase and glucosamine-6-phosphate acetyltransferase activities, by measuring the production of Coenzyme A (CoA). The present invention finds use in the isolation of new classes of antifungal drugs, wherein the compounds have the ability to inhibit fungal glucose utilization.

The present invention provides methods for simultaneously assessing microbial phosphoglucose isomerase, ketol-isomerase and glucosamine-6-phosphate acetyltransferase activities, by measuring the production of Coenzyme A (CoA). The present invention finds use in the isolation of new classes of antifungal drugs, wherein the compounds have the ability to inhibit fungal glucose utilization.
During the last three decades there has been a dramatic increase in the frequency of fungal infections, especially disseminated systemic mycoses in immunocompromised patients (Cox and Perfect, Curr. Opin. Infect. Dis. 6:422-426 [1993]; and Fox, ASM News 59:515-518 [1993]). Human pathogenic fungi of particular importance include: Candida sp. (C. albicans, C. glabrata, C. krusei and C. parapsilosis), Aspergillus fumigatus, and Cryptococcus neoformans. C. albicans and A. fumigatus cause most opportunistic mycoses. At present, treatments for fungal infections are limited to few options. Amphotericin B (a polyene) is fungicidal, but is toxic to humans. Azoles (fluconazole, itraconazole, and others) are safer than amphotericin B, but are only fungistatic. In addition, resistance to azoles has become a major clinical concern. Some azoles (Sheehan, Clin. Microbiol. Rev. 12:40-79 [1999]) and a new class of (1,3)xcex2-glucan synthase inhibitors, echinocandins (Denning, J. Antimicrob. Chemother. 40:611-614 [1997]), are now in clinical and pre-clinical trials. Recently, the FDA approved caspofungin, a (1,3)xcex2-glucan synthase inhibitor, as a xe2x80x9csalvage treatmentxe2x80x9d for aspergillosis. In spite of the new azoles and the (1,3)xcex2-glucan synthase inhibitors, new classes of antifungal drugs are needed for therapy of infections caused by drug-resistant mutants (and species) or for preventing the emergence of drug-resistant mutants.
Fungal Infections and Drug Resistance
Fungal organisms have become increasingly significant pathogens in immunocompromised patients, especially those who because of cancer, organ transplantation, chemotherapy, pregnancy, age, diabetes, complications following extensive surgery, and various immune system dysfunctions, are at risk of experiencing life-threatening diseases caused by microorganisms which do not ordinarily pose a threat to normal, immunocompetent people. Other risk factors for deeply invasive fungal infections include protracted treatment using broad spectrum antimicrobials, corticosteroids, and vascular catheters.
Indeed, immunocompromised patients provide a significant challenge to modern health care delivery. For example, fungal infections have become one of the leading factors contributing to morbidity and mortality in cancer patients, and fungi account for 4-12% of nosocomial pathogens in leukemia patients (Anaissie, Clin. Infect. Dis., 14[Suppl. 1]:S43 [1992]). The incidence of nosocomial bloodstream infections with fungi such as Candida spp. (xe2x80x9ccandidemiaxe2x80x9d) has increased in recent years and has been reported to account for 5.6% of all primary bloodstream infections. There are an estimated 200,000 patients/year who acquire nosocomial fungal infections, with bloodstream infections having a mean mortality rate of 55% (See e.g., Beck-Sague et al., J. Infect. Dis., 167:1247 [1993]; and the Centers for Disease Control website at www.cdc.gov/ncidod/publications/brochures/hip.html). Fungal infections in non-humans, such as livestock, is also of significant health and economic concern. The most common fungal pathogens in humans are the opportunistic yeast, Candida albicans and the filamentous mold, Aspergillus fumigatus (See, Bow, Br. J. Haematol., 101:1 [1998]; and Warnock, J. Antimicrob. Chemother., 41:95 [1998]).
C. albicans is the most common fungal pathogen in humans, with other Candida species becoming increasingly important in fungal disease in humans and other animals (See, Walsh and Dixon, xe2x80x9cSpectrum of Mycoses,xe2x80x9d in Baron [ed.], Medical Microbiology, 4th ed, University of Texas Medical Branch, Galveston, Tex. [1996], pp. 919-925). Approximately 200 Candida species are recognized, with approximately seven of those species isolated with significant frequency from human specimens (See, Warren and Hazen, Ch. 95, pp. 1184-1199, xe2x80x9cCandida, Cryptococcus, and Other Yeasts of Medical Importance,xe2x80x9d in Murray et al., [eds.], Manual of Clinical Microbiology, 7th ed., ASM Press, Washington, D.C. [1999]; and Mitchell, in Zinsser Microbiology, Joklik et al., [eds], Appleton, Century-Crofts, Norwalk, Conn., pp. 1183-1190 [1984]).
The clinical manifestations of Candida infections and disease are many and varied, as Candida species are known to invade most organ systems of the body. Superficial candidiasis may involve the epidermal and mucosal surfaces (e.g., the oral cavity, pharynx, esophagus, intestines, urinary bladder, and vagina). In deep candidiasis, the gastrointestinal tract and intravascular catheters are the two major portals of entry, with the kidneys, liver, spleen, brain, eyes, heart, and other tissues being the major sites involved.
The major difficulties in treating Candida infections are encountered in cases of systemic disease. Chronic mucocutaneous, pulmonary candidiasis, endocarditis, and fungemia must be diagnosed early in order to avoid fatality. The incidence of candidiasis in certain patient populations is striking. Up to 30% of leukemia patients acquire systemic candidiasis (Anaissie, Clin. Infect. Dis., 14[Suppl. 1]:S43 [1992]). This is of great significance, as some reports indicate that the fatality rate for disseminated candidiasis in cancer patients is as high as 80% (Meunier, et al., Clin. Infect. Dis., 14[Suppl. 1]:S120 [1992]).
Aspergillus species are the second most common isolate, after Candida species, in patients with positive fungal cultures (See, Sigler and Kennedy, Ch. 97, xe2x80x9cAspergillus, Fusarium, and Other Opportunistic Moniliaceous Fungi,xe2x80x9d in Murray et al., (eds), Manual of Clinical Microbiology, 7th ed., ASM Press, Washington, D.C. [1999], pp. 1213-1241; and Goodwin et al., J. Med. Vet. Mycol., 30:153 [1992]). A large number of species of the genus Aspergillus have clinical relevance, although A. fumigatus, A. niger and A. flavus are most commonly isolated. Of these isolates, A. fumigatus is the most common human pathogen. Three main types of disease have been associated with A. fumigatus, namely allergic asthma, aspergilloma, and invasive aspergillosis (See e.g., Lortholary et al., Amer. J. Med., 95:177-187 [1993]).
Allergic pulmonary asthma due to A. fumigatus exposure affects an estimated 50,000 individuals in the United States alone. Aspergillomas are formed when fungal spores germinate in situ in tissue such as the lungs and form fungus balls. There is typically no invasion of underlying tissues, and in most cases treatment involves the simple surgical removal of the aspergilloma. However, invasive aspergillosis involves the invasion of host tissues, and is most commonly observed in patients with predisposing conditions (e.g., immunosuppressive drugs, neutropenia, chemotherapy, AIDS). Transplant (e.g., bone marrow or organ) and chemotherapy patients are at the greatest risk for this form of aspergillosis (See e.g., Denning et al., New Eng. J. Med., 324:654-662 [1992]; and Miller et al., Chest 105:37-44 [1994]). The prognosis for patients with invasive aspergillosis is particularly grave, with mortality rates greater than 50% (See e.g., Polis et al., xe2x80x9cFungal Infections in Patients with the Acquired Immunodeficiency Syndrome,xe2x80x9d in DeVita et al. (eds), AIDS: Biology, Diagnosis, Treatment, and Prevention, 4th ed., Lippincott-Raven, [1997]), due to the lack of a rapid diagnostic method to confirm A. fumigatus infection, and the lack of safe antifungal drugs.
The development of effective antifungal agents has lagged behind that of antibacterial agents. Fungi, like humans, are eukaryotic. Thus, most agents that have antimicrobial activity towards fungi are also toxic to humans (i.e., due to non-selective toxicity). Four general groups of antifungals have been developed; these are the polyenes, the azoles, the allylamines/morpholines, and the antimetabolites. Despite the identification of cell membrane, cell wall, and microtubule targets for antifungal action, antifungal development has been slow.
The polyene antifungals (e.g., amphotericin B and nystatin) target the fungal cell membrane, which is similar to mammalian plasma membranes, with the exception being that fungal plasma membranes contain ergosterol, rather than cholesterol as the principal sterol. The polyene amphotericin B remains the treatment mainstay for life-threatening and other mycoses, including candidiasis, cryptococcosis, aspergillosis, zygomycosis, coccidioidomycosis, histoplasmosis, blastomycosis, and paracoccidioidomycosis. Amphotericin B must be administered intravenously and is associated with numerous, often serious side effects, including phlebitis at the infusion site, fever, chills, hypokalemia, anemia and nephrotoxicity. Nystatin is another broad-spectrum polyene antifungal. However, its toxicity to humans prevents its widespread use. Currently, it is limited to topical applications, where it is effective against yeasts, including C. albicans.
The azole antifungals (e.g., fluconazole, itraconazole, and ketoconazole) and the allylamine and morpholine antifungals (e.g., naftifine and terbinafine) interfere with ergosterol biosynthesis. Ketoconazole may be used to treat histoplasmosis, blastomycosis, mucosal candidiasis and various cutaneous mycoses (e.g., dermatophyte infections, pityriasis versicolor, and cutaneous candidiasis). However, it is not useful for treatment of aspergillosis or systemic yeast infections. Side effects associated with use of the azoles are not as severe as those associated with amphotericin B, although life-threatening hepatic toxicity may result from long-term azole use. Other side effects include nausea, vomiting, and drug interactions with such compounds as cyclosporin, antihistamines, anticoagulants, anti-seizure and oral hypoglycemic medications.
The few antimetabolite antifungals identified have not found widespread use. The most commonly used antifungal is 5-fluorocytosine, a fluorinated analog of cytosine. However, as with other antimetabolites, drug resistant fungal strains have emerged, and 5-fluorocytosine is seldom used alone. Nonetheless, in combination with amphotericin B, it remains the treatment of choice for cryptococcal meningitis, and is effective against some diseases caused by dematiaceous fungi.
Griseofulvin, an antifungal compound produced by Penicillium griseofulvin, acts by targeting microtubule-associated proteins. Griseofulvin is active against most dermatophytes, and is commonly used to treat dermatophytic infections. Potassium iodide is another compound that is used as an antifungal to enhance transepidermal elimination of fungal organisms in cases of cutaneous and lymphocutaneous sporotrichosis, although it is not effective against Sporothrix schenckii in vitro.
As with bacteria, drug-resistant strains of fungal pathogens have also been reported. This drug resistance can take various forms, such as primary resistance, where the susceptibility profiles for the species are characteristic, inherent, and rarely change in response to drug exposure, or the resistance can be secondary (i.e., acquired). Some of the molecular and cellular mechanisms by which fungal organisms acquire resistance are known (White, ASM News 63:427-433 [1997]; and White et al., Clin. Microbiol. Rev., 11:382-402 [1998]).
Significantly, fungal resistance to amphotericin B has been reported for various opportunistic fungi, including Pseudallescheria boydii, Fusarium, Trichosporon, and some C. lusitaniae and C. guilliermondii isolates (See, Dixon and Walsh, xe2x80x9cAntifungal Agents,xe2x80x9d in Baron (ed.), Medical Microbiology, 4th ed., University of Texas Medical Branch, Galveston, Tex. [1996], pp. 926-932). In addition, the emergence of azole-resistant fungal strains has raised concerns regarding use of the azole compounds, especially fluconazole, as a front-line treatment (Boschman et al., Antimicrob. Agents Chemother., 42:734 [1998]; Graybill, Clin. Infect. Dis., 22(Suppl. 2):S166 [1996]; White, ASM News 63:427-433 [1997]; and White et al., Clin. Microbiol. Rev., 11:382-402 [1998]).
In view of the development of resistance, as well as the relative lack of variety available in the selection of antifungals, there remains a need for the development of compounds useful for treatment of fungal diseases.
Selective Toxicity
The principle of selective toxicity is fundamental to the development of successful antimicrobial agents. That is to say, an antimicrobial compound, while toxic to the microorganism, ideally is not toxic to the subject receiving the antimicrobial compound. Selective toxicity is often a reflection of differences between the microorganism and host physiologies.
One approach to achieving selective toxicity is to identify a compound that is able to inhibit an essential enzyme in the microorganism, but due to differences in enzyme structure or function, that same antimicrobial compound does not affect the homologous enzyme in the host. Alternatively, an antimicrobial compound can inhibit a biochemical event that is essential to the microorganism, but that biochemical process may not be present or be essential to the host.
Chitin Biosynthesis
The fungal cell wall is essential for the viability of the organism, and is a rigid, stratified structure consisting of chitinous microfibrils and polysaccharides, among other components. The cell wall provides support and shape to the cell, and prevents osmotic lysis of the cell. Indeed, even a small lesion within the cell wall can lead to the extrusion of cytoplasm due to the positive intracellular pressure (See, Cole, xe2x80x9cBasic Biology of Fungi, in Baron (ed.), Medical Microbiology, 4th ed., University of Texas Medical Branch, Galveston, Tex. [1996], pp. 903-911). The yeast form of the C. albicans cell wall contains approximately 30-60% glucan, 25-50% mannan (mannoprotein), 1-2% chitin, 2-14% lipid, and 5-15% protein (McGinnis and Tyring, xe2x80x9cIntroduction to Mycology,xe2x80x9d in Baron (ed.), Medical Microbiology, 4th ed., University of Texas Medical Branch, Galveston, Tex. [1996], pp. 893-902). The chitin within the fungal cell wall is a (1-4)xcex2-linked polymer of N-acetyl glucosamine (GlcNAc) polymerized by chitin synthase at the plasma membrane (See, FIG. 1).
Chitin, although a minor component of yeast and filamentous fungal cell walls, is essential for cell viability and mother-daughter cell separation. Chitin biosynthesis, which requires uridine diphosphate-N-acetyl glucosamine (UDP-GlcNAc), is complex and is catalyzed by at least three gene products in S. cerevisiae, and perhaps as many as six gene products in certain filamentous molds (Bulawa, Ann. Rev. Microbiol., 47:505-534 [1993]; and Mellado et al., Mol. Genet., 246:353-359 [1995]). The three yeast genes, csI, csII and csIII, each have homologues in C. albicans and each performs a different intracellular function.
UDP-GlcNAc is the substrate for chitin synthase. Normal levels of UDP-GlcNAc are required for chitin biosynthesis and subsequent cell wall assembly and growth (Katz and Rosenberger, Biochim. Biophys. Acta., 208:452-460 [1970]). The pathway for the synthesis of UDP-GlcNAc, known as the Leloir pathway (Leloir and Cardini, Biochim. Biophys. Acta., 12:15-22 [1953]) is shown in FIG. 1. In this Figure, chitin synthase activity is shown for context, but is not considered part of the Leloir pathway. The first pathway-specific enzyme is 2-amino-2-deoxy-D-glucose-6-phosphate ketol-isomerase (known simply as ketol-isomerase; E.C. 220.127.116.11 or E.C. 220.127.116.11). The ketol-isomerase is an amino transferase that forms glucosamine-6-phosphate (GlcN-6-P) and glutamate from fructose-6-phosphate and glutamine (Selitrennikoff and Sonneborn, Develop. Biol., 54:37-51 [1976]). The second enzyme in the pathway is aminodeoxyglucosephosphate acetyltransferase (E.C. 220.127.116.11), which converts S-acetyl CoA and GlcN-6-P to CoA and N-acetylglucosamine-6-phosphate (GlcNAc-6-P) (Selitrennikoff and Sonneborn, Develop. Biol., 54:37-51 [1976]). The third enzyme is acetylaminodeoxyglucose phosphomutase (also known as GlcNAc-phosphomutase; E.C. 18.104.22.168) which converts GlcNAc-6-P to GlcNAc-1-phosphate, employing Glc-1,6-phosphate as a co-factor. The most downstream enzyme is UTP:acetylaminodeoxyglucose-1-phosphate uridylyl transferase (E.C. 22.214.171.124), which converts UTP and GlcNAc-1-phosphate to UDP-GlcNAc and pyrophosphate (PPi) (Selitrennikoff and Sonneborn, Biochim. Biophys. Acta., 451:408-416 [1976]; and Etchebehere et al., J. Bacteriol., 175:5022-5027 [1993]).
Chitin synthase has been a target for the identification of antifungal compounds for over 30 years, yet only two classes of compounds that target this enzyme have been identified. These are the competitive substrate inhibitors, namely the polyoxins and the nikkomycins. Each of these enzymatic inhibitors resembles the structure of the substrate, UDP-GlcNAc, and has inhibition constants (Ki) in the xcexcM range (Decker et al., J. Gen. Microbiol., 137:1805-1813 [1991]). Unfortunately, nikkomycin shows rapid degradation in biological fluids in rat, mouse and rabbit model systems (Tokumura and Horie, Biol. Pharm. Bull., 20:577-580 [1977]).
Thus, there remains a need to identify new antifungal compounds, and more specifically, there is a need to identify new classes of antifungal compounds that are effective against various fungal organisms, including those that are resistant to currently used compounds. Indeed, there remains a need to identify and develop new classes of antimicrobial compounds that are effective against multiple-drug resistant organisms. In addition, there is a need to identify and develop antimicrobial compounds that demonstrate selective toxicity towards microorganisms, but are not toxic, or have minimal (i.e., tolerable) toxicity, to animal hosts (e.g., humans).
The present invention provides methods for simultaneously assessing microbial phosphoglucose isomerase, ketol-isomerase and glucosamine-6-phosphate acetyltransferase activities, by measuring the production of Coenzyme A (CoA). The present invention finds use in the isolation of new classes of antifungal drugs, wherein the compounds have the ability to inhibit fungal glucose utilization.
In one embodiment, the present invention provides methods for the detection of phosphoglucose isomerase, ketol-isomerase and acetyltransferase activities in a sample, comprising the steps of a) providing: a sample suspected to contain phosphoglucose isomerase, ketol-isomerase and acetyltransferase activities, glucose-6-phosphate, glutamine, acetyl coenzyme A, and 5,5xe2x80x2-dithiobis(2-nitrobenzoic acid); b) combining the sample, glucose-6-phosphate, glutamine, and acetyl coenzyme A under conditions to yield reaction products comprising coenzyme A and N-acetylglucosamine-6-phosphate; c) inactivating the phosphoglucose isomerase, ketol-isomerase and acetyltransferase activities; and d) combining the reaction product comprising coenzyme A and 5,5xe2x80x2-dithiobis(2-nitrobenzoic acid) under conditions to yield a chromogenic reaction product comprising 2-nitro-thiobezoate anion, wherein the chromogenic reaction product is indicative of phosphoglucose isomerase, ketol-isomerase and acetyltransferase activities. In a related embodiment, the sample comprises a lysate selected from the group consisting of crude cell lysates and gel filtered cell lysates. In some embodiments, the lysate is a fungal cell lysate selected from the group consisting of Aspergillus cell lysates, Candida cell lysates, Cryptococcus cell lysates, Histoplasma cell lysates, Pneumocystis cell lysates, Rhizopus cell lysates, Saccharomyces cell lysates, and Schizosaccharomyces cell lysates. In one embodiment, the sample comprises purified fungal enzymes while in another embodiment the sample comprises recombinant fungal enzymes, where the fungal enzymes are selected from the group consisting of phosphoglucose isomerases, ketol-isomerases and acetyltransferases.
In other embodiments, the present invention provides methods for the detection of a compound having the ability to inhibit phosphoglucose isomerase, ketol-isomerase and/or acetyltransferase activities in a sample, comprising the steps of: a) providing a sample suspected to contain phosphoglucose isomerase, ketol-isomerase and acetyltransferase activities, glucose-6-phosphate, glutamine, acetyl coenzyme A, 5,5xe2x80x2-dithiobis(2-nitrobenzoic acid), and a candidate compound; b) preparing a first and second reaction mixture, where the first reaction mixture comprises the sample, glucose-6-phosphate, glutamine, and acetyl coenzyme A, and where the second reaction mixture comprises the sample, glucose-6-phosphate, glutamine, acetyl coenzyme A and the candidate compound; c) incubating the first and second reaction mixtures under conditions to yield reaction products comprising coenzyme A and N-acetylglucosamine-6-phosphate; d) inactivating the phosphoglucose isomerase, ketol-isomerase and acetyltransferase activities; e) combining the first and second reaction mixtures with 5,5xe2x80x2-dithiobis(2-nitrobenzoic acid) under conditions to yield a chromogenic reaction product comprising 2-nitro-thiobezoate anion; and f) comparing the quantity of the chromogenic reaction product in the first and second reaction mixtures. In a related embodiment, these methods further comprise step g) scoring the candidate compounds as positive for the ability to inhibit phosphoglucose isomerase, ketol-isomerase and/or acetyltransferase activities in a sample, when the second reaction mixture yields less than 50% of the chromogenic reaction product of the first reaction mixture. In other embodiments, the sample comprises a lysate selected from the group consisting of crude cell lysates and gel filtered cell lysates. In some embodiments, the lysate is a fungal cell lysate selected from the group consisting of Aspergillus cell lysates, Candida cell lysates, Cryptococcus cell lysates, Histoplasma cell lysates, Pneumocystis cell lysates, Rhizopus cell lysates, Saccharomyces cell lysates, and Schizosaccharomyces cell lysates. In one embodiment, the sample comprises purified fungal enzymes, while in another embodiment the sample comprises recombinant fungal enzymes, where the fungal enzymes are selected from the group consisting of phosphoglucose isomerases, ketol-isomerases and acetyltransferases. In some embodiments, the candidate compound is present in an extract selected from the group consisting of extremophile extracts, marine macroorganism extracts, cyanobacterial extracts and algal extracts.
In some embodiments, the present invention also provides compositions comprising at least one candidate compound which has the ability to inhibit phosphoglucose isomerase, ketol-isomerase and/or acetyltransferase activities in a sample, identified by methods comprising the steps of: a) providing a sample suspected to contain phosphoglucose isomerase, ketol-isomerase and acetyltransferase activities, glucose-6-phosphate, glutamine, acetyl coenzyme A, 5,5xe2x80x2-dithiobis(2-nitrobenzoic acid), and a candidate compound; b) preparing a first and second reaction mixture, where the first reaction mixture comprises the sample, glucose-6-phosphate, glutamine, and acetyl coenzyme A, and where the second reaction mixture comprises the sample, glucose-6-phosphate, glutamine, acetyl coenzyme A and the candidate compound; c) incubating the first and second reaction mixtures under conditions to yield reaction products comprising coenzyme A and N-acetylglucosamine-6-phosphate; d) inactivating the phosphoglucose isomerase, ketol-isomerase and acetyltransferase activities; e) combining the first and second reaction mixtures with 5,5xe2x80x2-dithiobis(2-nitrobenzoic acid) under conditions to yield a chromogenic reaction product comprising 2-nitro-thiobezoate anion; and f) comparing the quantity of the chromogenic reaction product in the first and second reaction mixtures. In a related embodiment, these compositions comprising at least one candidate compound which has the ability to inhibit phosphoglucose isomerase, ketol-isomerase and/or acetyltransferase activities in a sample are identified by methods which further comprise step g) scoring the candidate compounds as positive for the ability to inhibit phosphoglucose isomerase, ketol-isomerase and/or acetyltransferase activities in a sample, when the second reaction mixture yields less than 50% of the chromogenic reaction product of the first reaction mixture. In some embodiments, the candidate compound is present in an extract selected from the group consisting of extremophile extracts, marine macroorganism extracts, cyanobacterial extracts and algal extracts. In other embodiments, the candidate compound is present in a high performance liquid chromatography (HPLC) fraction of a microbial extract. In one embodiment, the candidate compound further has antifungal activity. In some embodiments, the antifungal activity is determined by a test selected from the group consisting of agar diffusion assays, broth dilution assays, and animal model assays. In preferred embodiments, the antifungal activity is selected from the group consisting of anti-Aspergillus activity, anti-Candida activity, anti-Cryptococcus activity, anti-Histoplasma activity, anti-Pneumocystis activity, anti-Rhizopus activity, anti-Saccharomyces activity, and anti-Schizosaccharomyces activity. In some embodiments the candidate compound further has limited toxicity to mammalian cells. In preferred embodiments, the mammalian cells are selected from the group consisting of murine cells and human cells. In a further preferred embodiment, the limited toxicity is determined by a test selected from the group consisting of in vitro and in vivo acute toxicity tests.

Methods for the identification of fungal glucose utilization inhibitors and antifungal agents


A learning tool and method of creating the same wherein words are arranged according to similarities or commonalties such that a user may more efficiently acquire knowledge of a foreign language based on an association method of learning. The learning tool is comprised of a plurality of words of a first known language and a second foreign language, wherein each word of the first language has a corresponding translation in the second language. The words of each language are compared and categorized into at least first and second groups A and B, wherein group A words possess one or more identifiable similar characteristics based on predetermined criteria. Group B, on the other hand, is comprised of words having dissimilar characteristics. Groups A and B are divided into subgroups according to parts of speech and gender characteristics, as identified, such that as groups A and B are further divided, each subgroup includes L1 words and L2 translations sharing more similar characteristics than the preceding group. The learning tool permits users to learn a foreign language by associating like words with one another.

Dictionaries and the like comprising translations of two different languages (a known and foreign language) are well known in the art. Conventional foreign language dictionaries typically provide a translation of a known language into a foreign language and the reciprocal, wherein a predetermined selection of words of each language is arranged alphabetically into a first column and a translation thereof into a second, adjacent column. Users of conventional dictionaries of this type simply look up a desired word in the appropriate language, either known or foreign, to determine the foreign language equivalent or definition, respectively. Conventional foreign language dictionaries of this type, while useful, typically do not enable users thereof to learn a foreign language, or even acquire general understanding of an unfamiliar language, when used without other instructional methods or materials. That is, to learn a foreign language utilizing such a tool would require the user to memorize voluminous amounts of words arranged in no particular order, other than alphabetical. Furthermore, information acquired from random memorization tends to significantly diminish over time.
In addition to conventional foreign language dictionaries, "phrasebooks" are also commonly utilized tools for understanding and speaking a foreign language, as shown, for example, in U.S. Pat. No. 6,024,571 issued to Renegar. Such books have been devised primarily for assisting travelers in a foreign country to understand and respond to common phrases. While the information contained therein tends to be organized, where phrases or terms are separated into categories relating to specific situations or topics such as greetings, dining situations, directions, etc., the information contained in phrasebooks is negligible in comparison to dictionaries. Therefore, phrasebooks and the like are insufficient to provide users with more than a minimal understanding of a foreign language.
More recent developments in the field of foreign language acquisition include, for instance, the method and system disclosed in U.S. Pat. No. 6,341,958 issued to Zilberman which teaches a method and system for acquiring a foreign language by way of switching-off subconscious translation into a native language with the aid of a plurality of drills. In particular, the drills consist of the simultaneous reading of a lesson in a foreign language, listening to the recording of the same lesson, and repeating the lesson to learn a foreign language.
While recent techniques and tools have alleviated some of the drawbacks of conventional learning tools, a need still exists for a simplified technique and learning tool that enables users to learn a foreign language by focusing on the commonalties between a first and second language, i.e., an "association method of learning," such that information acquired is more readily retained.
Accordingly, it is an object of the present invention to provide a foreign language learning tool and method of creating the same having a simplified organization of terms based on the commonalties between two predetermined languages.
It is another object of the present invention to provide a learning tool that enables a user to gain a comprehensive understanding of the vocabulary of a predetermined foreign language.
Yet another object of the present invention is to provide a method for learning a foreign language that includes the use of a learning tool organized in a manner that focuses on the commonalties between two predetermined languages and repetition of the terms therein to enhance the likelihood of retention of the foreign language.
It is a further object of the present invention to provide a learning tool that can be adapted for use by all ages and levels of understanding.
A still further object of the present invention to provide a foreign language-learning tool and method of creating the same wherein the deficiencies of conventional translation "dictionaries" are mitigated.

Foreign language learning tool and method for creating the same


The present invention is a probe forming device, the probe forming device comprises a spinning shaft, a first adjusting structure, a second adjusting structure, an electrolyte conveying member and a power supply. One of the holding member of the spinning shaft holds a workpiece, and a driving member drives the workpiece to move and abut the first adjusting structure and the second modulating structure. The electrolyte conveying member conveys an electrolyte to the workpiece, the first adjusting structure and the second adjusting structure, and is electrically connected. At least one positive end of the power supply is connected to the workpiece or the spinning shaft, and at least one negative end is connected to the first adjusting structure and the second modulating structure.

The manufacturing apparatus for probes according to the prior art is to drive a grinding wheel to grind a rod material to a probe. Alternatively, a rod material is placed on a laid-flat sandpaper and grinded back and forth. Either way, the consumption of grinding wheels and sandpapers is extremely rapid.
According to the method for manufacturing probes according to the prior art, a rod material is first grinded by the grinding wheel of a grinder or a sandpaper. Then the shape of the probe is examined to check if damages exist. Since the above method adopts manual grinding, depending on the grinding force, angle, and direction by the operator, different grinding results will be produced. In addition, the properties of the rod material, such as hardness and density, also influence the result of forming a probe form a rod material. Thereby, repeated grinding and confirmation are required to ensure the shape of probes. It is the repeated confirmation and grinding makes the manufacturing time long. Besides, the probability of damages is high, which makes the manufacturing time even longer.
Furthermore, as modern technologies develop, the chip size shrinks gradually, urging the size of the probes for testing shrinks accordingly. Thereby, in addition to the manufacturing method according to the prior art, there is also an electrochemical machining (ECM) method to manufacture probes with sizes smaller than 200 μm. The ECM method is to perform machining by electrochemical dissolution using a metal workpiece as the anode. The method is not an electrolysis machining method according to the prior art. It can be applied to machining extremely hard materials, such as tool steel, hard alloy, superalloy, or titanium alloy, or the materials difficult to be processed by the methods according to the prior art. The main requirement of the ECM method is that the object under machining must be conductive. While performing ECM, the cutting tool is the cathode and the object under machining is the anode. Under low-voltage and high-current condition, the electrolyte can circulate rapidly through the electrodes and the object under machining under pressure for electrolysis. The cutting tool moves along the machining path and does not contact the object under machining. No sparks will occur in the process. The object under machining is immersed in the electrolyte and dissolved in the machining process. Then the cutting tool is used to shape the object under machining.
Although the ECM method can manufacture the desired shape of the object under machining rapidly, the electrolysis must be performed under a high pressure. Thereby, expensive instruments and equipment must be invested before the machining method can be performed.
According to the three methods described above, it is known that grinding using grinders or sandpapers takes longer processing time has higher probability of damages. Although the ECM method can manufacture the shape of object under machining rapidly and accurately, the costly machines required make the manufacturing costs expensive.
Accordingly, to solve the endurance problem of grinding wheels and sandpapers as described above, improve the production efficiency for probes, shorten the processing time effectively, and reduce the manufacturing costs by avoiding special instruments and equipment, the present invention adopts an electrolysis method and an improved probe forming device to solve the above problems.
According to the above description, the present invention provides a probe forming device, which uses an angle adjusting member to adjust the angle of probe tip after forming. In addition, negative charges are provided to the workpiece and positive charges are provided to the angle adjusting member. By using the electrolyte, the workpiece and the angle adjusting member connected electrically to form the required shape of probes.

Metal Industries Research & Development Centre


A road inventory system includes a mobile unit and a stationary unit. The mobile unit includes a vehicle which has a metric database for delivering information relating to an area to be surveyed, a plurality of video cameras taking pictures of respective parts of the area on a first recording medium with associated address signals, and a data recording apparatus which records on a second recording medium relevant data from the database together with vehicle motion information, the data recording apparatus producing the address signals. The stationary unit includes a video display for reproducing on several screens the video information on the first recording medium, a data reproducing apparatus for reproducing the data recorded on the second recording medium and storing it in a data inventory system, and a data processing arrangement for combining and recording on a third recording medium a selection of the video and data information from the first and second recording mediums.

1. Field of the Invention
In the world of traffic and transport an ever increasing number of electronic devices are being put into use; in particular there is a marked increase of computer applications, also on-board of vehicles. It is obvious that on-board computers should be perfected so that they can also be used for determining:
routes and distances;
generation of site information;
the use of these data for the purpose of navigation;
the processing of (coded) up-to-date route information via a radio receiver. The procedure to describe here concentrates on the technique of the initial collection of the data necessary for navigation.
To make navigation via the on-board computer possible, two conditions are to be met in principle:
(a) the availability of an electronic map, as it were the framework within or across which one moves, and
(b) the updating of the location of the vehicle within the limits referred to in (a).
The procedure to be described constitutes a means to solve the problem of the production and updating of data files for an electronic map as mentioned in (a) in the most efficient way.
The required data files which will be made for the purpose of navigation of the motorized road traffic now consist of two groups of data:
(1) metrical data: the system of co-ordinates;
(2) non-metrical data which are added to the metrical data. There are a great many non-metrical data, for the greater part referring to matters of traffic technique and other traffic and object information. These very large files can be made accessible to the user via CD-ROM only. Solving the problem of compiling and updating those files in a very efficient way depends, on the one hand, on the application of a perfectly equipped production process and, on the other hand, on a ready support of that production process by supplying it with up-to-date information, both to enable the file (=map) to be as complete and up-to-date as possible, and to largely reduce expensive additional investigation in the field. The procedure to be described is aimed at the last mentioned aspects.
This invention relates to a road inventory system for gathering visual data from which road data files can be generated, in order to compile and to update a road data base. This road inventory system consists of three main parts:
a mobile unit, for video registration and measuring;
a stationary unit for editing and post processing;
a customer set, a desk-top user display and retrieval system.
2. Description of the Prior art
U.S. Pat. No. 4,396,942 discloses a method for video surveying, comprising the steps of: video recording all locations to be surveyed from a predetermined control position, for subsequent playback on a monitor screen. The method uses an overlay to the monitor screen or actual measurement in the terrain to ascertain actual distances, and allow for adding notes to the video recordings. The video survey may be conducted from a moving vehicle, using a video cassette recording apparatus.
U.S. Pat. No. 4,635,136 discloses a method and apparatus for storing a massive inventory of labeled images. The inventory is produced on different frames of a video disc, from which the images may be randomly accessed for use in tax assessment, real estate sales and the like. Digital information is accessed from memory associated with a computer and monitored to define a route for a field rig, equipped with a video camera, which scans the images and provides TV signals in the order in which the digital information corresponding to the image to produce TV signals with labeling information therein. Pluralities of frames of the TV signals are recorded on a video recorder. A single frame is selected from each plurality and recorded on a different frame of the video disc record.
U.S. Pat. No. 4,495,500 discloses a system for gathering topographic data for use in computer generation of topographic maps of various forms. This system includes equipment mounted in an aircraft which can be flown over a terrain area which is to be surveyed. The equipment comprises a low frequency radar which is capable of penetrating foliage in the survey area for generating a signal representative of the distance from the aircraft to the terrain surface. Also a precision altimeter, temperature and humidity sensors, a clock and a digital recorder are included. The recording medium can be removed from the aircraft. Concurrent with the gathering of data in the aircraft, temperature and humidity data and at surface of the earth are gathered and recorded. Combination of the recordings can be used as computer input to produce accurate topographic maps.
U.S. Pat. No. 4,360,876 discloses an indicator system which satisfies multiple flight-mission requirements by providing an aircraft pilot with a visual display consisting of a movable map and navigational data. The map is stored in video form in a high-capacity compact mass memory consisting of a video disk. The system further comprises a symbol and character generator, intermediate memory and a TV monitor. The unit is controlled by a micro processor on the basis of data relating to latitude, longitude and heading of the aircraft.
U.S. Pat. No. 4,689,748 discloses a device for use on aircraft or spacecraft providing data corresponding to the course and orientation of the craft, and a digital display of the terrain over which the craft is travelling. It is a digital image scanning device, making use of the principle of aerial triangulation by tying in sequential images. The device, in combination with a computer, produces information in digital form and with unequivocal co-ordinate determination. F.i. distortion-free representation or read-out of the terrain can be produced.
U.S. Pat. No. 4,543,603 discloses a reconnaissance system comprising an air-borne vehicle capable of moving above a territory to be surveyed by rotating about its longitudinal axis, and means for taking images disposed on board the vehicle to observe said territory by a helicoidal scanning in relation with the rotation of the vehicle, wherein the vehicle is of the self-propelled missile type and the sensitive members are formed by at least one linear assembly of photosensitive elements disposed parallel to the longitudinal axis of the missile to give at each line an image of an elementary strip of territory which scans a strip of territory upon each revolution of the missile, the total image of the territory being formed by the plurality of images of the successive strips.
DE Pat. No. 3,235,993 discloses a system for electronic recording of commercial available maps on audio tape for instance in order to use these tapes in cars or other places, by reproducing (parts of) these maps on a monitor.

System for setting up and keeping up-to-date datafiles for road traffic


A hoisting system for hoisting a load relative to a body includes a hoisting cable, a hoisting mechanism selectively operable to deploy and retract the hoisting cable, and a guide mechanism movably mounted to the body at a position between the body and the hoisting cable. The guide mechanism includes at least one locking device that selectively locks the guide mechanism against movement in a first direction.

Exemplary embodiments pertain to a hoisting system, and more particularly, to a deflector or guide for minimizing damage during operation of a hoisting system.
Rescue hoists, such as used on a helicopter for example, typically include a lifting device, such as a hoist or winch, a hoist cable deployed and retrieved by the hoist, and an attachment located at the end of the cable for coupling to a person or cargo. The hoist is commonly a rotary drum, and the hoisting cable is wound or unwound about the drum to raise and lower the hoisting cable and/or a load attached thereto.
Modern rescue hoists are typically operable at high speeds and have an extended length of usable cable. Particularly during high speed operation, as the hoist cable is lifted with a load attached, the load may begin to oscillate as it approaches the helicopter. With this movement, the hoist cable may hear against a surface of the helicopter, such as the door sill for example. This contact between the hoist cable and the airframe may result in damage to the cable.

Cable guide mechanism for a rescue hoist


Systems and methods of chip design and package implementation for attenuating noise in timing circuits, including phase-locked-loops (PLL) and delay-locked-loops (DLL), are disclosed. Embodiments of the present invention attenuate coupled noise, such as the effects of ground current surges, or power supply noise coupling through electro-static discharge (ESD) structures. In known systems, the ground supplies for the timing circuits are designed with power and ground supplies, separate from the core power and ground; although the ground supplies are connected via common VSSsubstrate, they are separated from pad ring output driver power and ground supplies. In embodiments of the present invention, the PLL or DLL and core supplies are kept separate from the output driver power and ground supplies, providing for improved systems and methods that attenuate the effects of ground current surges from chip output drivers as they switch from logic highs to logic lows.

1. Field of the Invention
The present invention relates generally to integrated circuits and methods of integrated circuit construction that provide attenuation of current surges, and more specifically to improved systems and method of chip design and package implementation for attenuating the effects of ground current surges in timing circuits.
2. Description of Related Art
In general, timing circuits are susceptible to surrounding circuit noise, which oftentimes increase the "jitter" of the oscillation frequency and phase of the desired timing signal. With the placement of increasing quantities of timing circuits and/or system clocks, for example phase-locked loops (PLLs) and delay-locked loops (DLLs), within the confines of each chip, the necessity of considering noise reduction for each timing circuit becomes increasingly important.
Specifically, capacitive filters alone between supply and ground have been shown not to relieve the root causes of power supply and ground noise. Further, capacitive coupling by way of Electro-Static Discharge (ESD) structures to sensitive timing circuits is a liability.
Additionally, system clocks are sensitive to all power supply and ground noise as well as noise from certain types of drivers, whether that noise is generated externally or internally to the integrated circuit chip. Thus, the supply and grounding methods for system clocks on an integrated circuit ("IC") chip, such as the PLLs and DLLs, are frequently isolated from the board supply and ground with inductive filters. Individual circuits of the PLL and DLL, such as voltage-controlled oscillators (VCOs), phase detectors, dividers, and charge pumps, then, are isolated from each other when integrating these circuits onto a single silicon chip.
Building upon the short-sighted foundational precepts of the subject isolation and grounding technologies, the direction promulgated by suppliers understandably also fails to present credible solution to the current noise problems. Specific instructions from vendors offering timing circuits, such as PLL (phase-lock loops) and DLL (delay-lock-loops) separate power supply nodes, ground nodes for the componenets of these circuits, i.e., the phase detector, voltage controlled oscillator, divider, and driver circuits. These circuits in turn isolate the supply and ground nodes of the chip core circuits from the timing circuits.
The teaching of this invention is consistent with vendor instructions only in so far as requiring separate power supplies but differ in that individual ground nodes are electrically tied to a common node.
In recent years, the combination of factors such as substrate noise induced by high current output drivers on the chip and power supplies with low voltage supply potentials has been shown to cause timing circuits to malfunction.
The magnitude of a timing circuit malfunction can be measured by the distortion of the circuit's clock periods and is often expressed in terms of "jitter". "Jitter" is the difference in phase between adjacent clock cycles in a cycle-to-cycle measurement, or between clock cycles separated by a specific number of intervening cycles. The latter measurement is termed "long-term cycle drift". In essence, then, a timing circuit's sensitivity to noise can be expressed in terms of clock jitter.
Clock jitter, given by the compression and expansion in a series of adjacent clock periods, can limit the time allotted for logic delays bounded between rising and falling clock edges. Jitter affects the overall operation of any given clock circuit, inter alia, by limiting the maximum operating frequency of the chip.
With respect to the isolation of clock jitter, power supplies in the range of 1.0 to 1.2 volts limit the headroom, and do not allow the use of current source isolation. In higher voltage supplies, e.g., those operating at 1.8 volts or greater, current source isolation circuits are traditionally inserted between the internal circuits and a noisy supply and ground to minimize the effects of clock jitter in sensitive circuits such as VCOs.
Conventionally, it has been assumed that isolating the power and ground circuits for each timing circuit on an IC was the way to reduce the jitter in the timing circuit. FIG. 1 illustrates an embodiment of such presently recommended practice for a conventional embedded PLL timing circuit, one with separate power and ground supplies. The circuit diagram 100 of FIG. 1 includes three representative sections of the chip 101, an Input/Output ("I/O") circuit 102, a core circuit 104, and a timing circuit 106 such as a Phase Lock Loop (PLL) or a Delay Lock Loop (DLL) circuit. As shown in FIG. 1, each of the three representative circuits is provided with its own supply voltage as well as its own ground supply. Specifically, I/O circuit 102 is provided with a first +3.3 volt power supply 110, and a 3.3 volt ground connection 112, while core circuit 104 is provided with a +1.0 volt power supply 116, and a 1.0 volt ground connection 118. Similarly, the timing circuit 106 in such conventional arrangements is connected to both a +3.3 volt power supply 122 and a +1.0 volt power supply 124, as well as complementary ground supplies of 3.3 volts 126 and 1.0 volts 128; these supply potentials being separate/distinct to provide the isolation between the timing circuits previously sought.
A chip 101, as described in connection with FIG. 1, is typically fabricated on a grounded, P-doped substrate. The ground pins are generally connected to the P-doped substrate with transistor ground taps to prevent circuit problems such as latch up. With respect to such substrate and grounding issues, illustrations of ground nodes and associated resistive connections to such ground nodes of exemplary chip 101 are set forth next in connection with FIG. 2. Common recommended usage excludes the use of metal to combine ground nodes for all on-chip circuits.
FIG. 2 is a representative cross-sectional view of chip 101, illustrating the resistive connectivity of ground nodes to a P-doped substrate 202. As shown in FIG. 2, a first ground node 206 is shown connected to the 1.0 volt ground supply 118 to the core circuit, a second ground node 208 is shown connected to the 1.0 volt ground supply 128 to the timing circuit, a third ground node 210 is shown connected to the 3.3 volt ground supply 126 to the timing circuit, and a fourth ground node 212 is shown connected to the 3.3 volt ground supply 112 to the I/O circuit. Each of the respective ground nodes, 206, 208, 210 and 212, in turn, is shown as being connected to the P-doped substrate 202 by means of a representative resistance, 226, 228, 230 and 232, respectively. The model representative resistances, 226, 228, 230 and 232, are indicative of the differing phase delays of the discharge pathways, especially with respect to the sensitivity many current low voltage technologies have concerning such impedance.
Accordingly, there is a need for timing circuits that attenuate the effects of ground current surges from chip output drivers in order to obtain low-noise timing circuits.

Circuits and methods that attenuate coupled noise


A dormant preparation (DC) is provided which is capable of inhibiting proliferation of various kinds of cells. The preparation comprises an extract which is obtained from cells or tissue originating in an organism capable of entering a phase of dormancy in at least one of its parts and comprises at least one substance which induces or maintains the state of dormancy in the organism from which the cells or tissue are derived. The DC may be used for a variety of indications including human medicine and cosmetics, plant growth control and food preservation.

Dormancy is a phenomena which is found in representatives of the plant kingdom as well as the animal kingdom.
The germination of various grains and seeds comprising the necessary propagation organs is delayed under certain circumstances and yet the grains or seeds are capable of germinating after various periods of time. The period of time in which germination of such seeds may be delayed varies and depends both on intrinsic properties of the seed as well as on the nature and extremity of the environmental conditions. Seeds have been shown to be in dormancy for a few days, a year, several years and even for more than several centuries (as was discovered lately in the case of some nympheaceae and seeds of trees of the Leguminosae family (Shen-Miller, J., et al., American Journal of Botany, 82:1367-1380, 1995)).
In some cases, the capability to develop dormancy lies in the embryo envelopes. In such a case, the separation of the envelopes from the embryo, result in its immediate termination.
In other cases, chemical growth inhibitors capable of preventing termination are present in the embryo itself and thus even a bare embryo may remain dormant (such as in the case of Rosaceae plants such as Kerria, Peach, etc.).
In plants, a state of dormancy may be found in the whole plant or in one or more of its parts. Dormant plants are plants which have two main metabolic states in their growth cycle. In their dormant state, the plants' metabolism is extremely low, and the plant growth process is significantly inhibited although differentiation of certain cells may occur. In their active state, the plants' metabolism rate is higher, the cells divide and differentiate and there is significant growth of various parts of the plant. In some cases, the whole plant enters the dormant state. Such is the case in Narcissus plants in which during the dormant state the only remaining viable part is the bulb which is in its dormant state. In other cases, some parts of the plants may be active while other parts may be in dormancy such as, for example, is the case of apple trees.
Substances capable of inhibiting germination have also been shown to be present in the juice of fleshy fruits or in other plant organs which produce juice. Examples are tomatoes, grapes, kiwi, watermelon and grapefruit wherein pips present in the fruit do not germinate although their surroundings are suitable for germination due to the water within the fruit.
Several plant-derived substances having an effect on cell proliferation have been reported. For example, European Patent Application No. 0381514 describes compositions comprising both naturally derived as well as synthetically prepared sphingolipids which have growth inhibitory activity on various kinds of cells. Another well known plant-derived substance having an anti-mitotic effect on various kids of human cells is the substance colchicine (Samson, F. E., A. Rev. Pharmac. Toxic 16:143 (1976)). The Narcissus alkaloid pretazettine, was shown to have a cytotoxic effect on Rausher virus-carrier cells as well as anti-leukemic activity in leukemic mice although the predominant activity of the substance was shown to be an antiviral activity (Furusawav. E. et al., Chemotherapy, 26:36-45, (1980) and Furusawa, E. et al., Proc. Soc. Exp. Biol. Med. 152:186-191, (1976)). Ulex europaeus seed extracts were shown to comprise a non glycoprotein lectin capable of reversibly inhibiting growth of certain lymphocytes as well as to inhibit the growth of various reticulo endothelial tumor cell lines (Pirofsky, B., et al., Vox-Sang, 42:295-303, (1982) and Pirofsky, B. et al., J. Biol. Response Mod, 2:175-185, (1983)). Root extract of Panex ginseng was shown to decrease DNA synthesis measured by [H3]-thymidine incorporation of V 79 Chinese hampster lung cells. Another substance, Narciclasine obtained from bulbs of various Narcissus varieties was shown, amongst other of its activities, to inhibit growth of wheat kernal radicals (Ceriotti, G., et al., Tumors 53:359-371 (1967)). Bulbs of Pancratium littoral collected in Hawaii were found to contain a product designated pancratistatin capable of inhibiting growth of various neoplastic cell lines in vitro (Pettit. G. R., et al., J. Nat. Prod, 49:995-1002 (1986)).
Against this, many plant extracts having an opposite effect on cells, i.e., capable of augmenting their proliferation were also described such as, for example, the methanolic extract from the root of Scutellaria baicalensis georgi were shown to significantly augment the cellular activity of fibroblasts (Chung, C. P., et al., Planta-Med, 61:150-153, (1995)). Gibberellin-like growth substances were found in six different plant species having bulbs (Staby, G. L., Hort. Science, 399-400 (1970)). Several cytokinins which were found in roots that developed from Narcissus bulbs had an effect on bulb growth of the plants in which they were detected (Vanstaden, J. V., Pflanzenphysiol., 86:323-30 (1978)).
The phenomena of dormancy may also be found in the animal kingdom, for example, in the small crustacean Artemia salina (Finamore and Clegg In: The Cell Cycle, Academic Press Ed., 249-278, 1969). The natural environment of this marine crustacea is usually briny ponds. After fertilization, the early stages of development of artemia involve the formation of a blastula which then becomes a gastrula. Under severe environmental conditions such as dehydration (drought), the gastrula is capable of forming a cyst wherein the whole organism enters a dormancy phase. The dormant artemia gastrula (commonly miscalled "artemia eggs") are capable of remaining in their dormant state for many years. When the encysted gastrula are rehydrated, the various metabolic activities of the artemia are resumed and protein synthesis can be seen after about 10 minutes. However, DNA synthesis and cell division are absent until about after 60 hours (Le Gal, Y, In: Biochimie Marine, (Ed. Masson) p. 176, 1988).
Various plant derived compositions (such as retinoic acid (U.S. Pat. No. 5,438,073) and α-hydroxy acids (Ditre, C. M., et al., J. Am. Acad. Dermatol., 34:187-195, 1996)) as well as animal derived extracts have been proposed for use in the cosmetic field for stimulating the proliferation and renewal of epidermal cells. Such compositions were considered to be useful in the cosmetic field where it is accepted that the natural renewal process of epidermis is slowed down with aging. It is believed that removal of the outer surface with simultaneous stimulation of growth of new cells in the inner layers of the epidermis to divide and migrate to the outer surface, will result in skin renewal and in a younger skin appearance. However, it is also known and has been recently shown that the increase in cell division is a crucial factor in converting normal cells into premalignant or malignant cells (Ames, B. N. et al., Environ. Health Perspect 101:35-44 (1993)).
It is also believed today that normal human and animal cells have a finite capacity to replicate. It has been shown that the number of mitotic events that cultured normal animal cells can undergo appear to be inversely related to the age of the donor from which they were obtained (Hayflick, L., Clin. Geriatr. Med., 1:15-27, (1985)). It has also been shown that cell cultures obtained from patients with accelerated aging syndromes undergo less replications than cell cultures obtained from age matched control individuals.
Glossary
The following is the meaning of some terms of which will be used in the text below:
Dormancy—a state in which there is a marked decrease in the metabolic rate of cells or tissues resulting in the inhibition of growth and proliferation of the cells or tissue.
Dormans—substances naturally found in cells or tissue and which are capable of inducing cells or tissue to enter a state of dormancy or of maintaining the dormant state in cells or tissues that have already entered that state. The dormans may be obtained from a variety of plant parts which are capable of entering into a state of dormancy; from juice of various fruits which contain dormans capable of inhibiting germination of seeds within the fruit; from animals which are capable of entering a phase of dormancy in their life cycle, e.g. gastrula of certain crustaceans such as artemia or dafnia; etc. In some cases: the dormans are found within a dormant tissue, e.g. in a dormant seed or in the gastrula of artemia or dafnia; in other cases the dormans are found in a tissue surrounding the dorman tissue or organ, e.g. in a fruit juice surrounding a dormant seed.
Extract—At least one substance obtained by any of a variety of extraction methods known in the art. For example, the extract may be an aqueous extract, a glycolic extract an alcoholic extract, an oily extract, etc. The extract in accordance with the invention is obtained from cells or tissues from a part of a plant or animal capable of entering a state of dormancy. The cells or tissue may be obtained directly from the plant or animal and the extract may then be prepared therefrom. Alternatively, cell cultures may first be prepared from the plant or animal cells or tissues and then the cell cultures may be grown for various periods of time. In order to prepare an extract, the cells are then harvested from the cell cultures, the cells and their growth medium are separated and an extract may be prepared either from the cells themselves or from the growth medium (which will be referred to as "supernatant") which contains substances secreted by the cells into their growth medium. Thus, the "extract" may be obtained directly from plant or animal tissue or from an animal or plant cell or tissue culture.
Dorman extract—an extract obtained from a plant cell or tissue, from fruit or from an animal cell or tissue which comprises dormans.
Enriched dorman preparation (EDP)—a preparation derived from a natural source which comprises dormans in a concentration larger than that which is found in a natural unprocessed extract. The EDP may be obtained by purification of a natural extract to obtain fractions which contained dormans in the larger concentration, e.g. by various chromatographic techniques, by filtration, etc., as well as by biological means including growing cells or tissue which are capable of producing dormans under conditions in which they produce dormans in relatively large quantities and collecting their secretion products. In order to determine whether a preparation is an enriched dorman preparation, the preparation may be assayed for a specific biological activity associated with dormans, as described below. EDP contains a substantially higher concentration of dormans as compared to the natural preparation, e.g. at least 1.5 folds, preferably 2 folds and typically at least 2.5 folds to the concentration of the dormans in the natural preparation.
Producer cells or producer tissue—cells or tissue which are capable of producing dormans which may thus be extracted therefrom.
Target cells or target tissue—cells or tissue which are contacted with dormans, in accordance with the in invention and which thereby enter a state of inhibition of their growth or proliferation or maintain such a state as the result of contact with dormans.
Dorman analog—a substance, typically synthetic, which has a dorman-like activity in that it is capable of inducing dormancy in the same cells or tissue induced to dormancy by the dorman and which in accordance with the invention, is also capable of inhibiting growth and proliferation of target cells or tissue.
Dorman composition (DC)—a composition comprising, as active ingredient, an amount of dorman (e.g. as a dorman extract) or dorman analog effective in inhibiting growth and proliferation of target cells or tissue ("effective amount"). A dorman composition may comprise a naturally derived EDP, a composition comprising synthetic dormans as well as dorman analogs.
Active Extract (AE)—extracts obtained from cells or tissues from a part of a plant or animal capable of entering a state of dormancy during the non dormant state.

Methods of inhibiting proliferation of cells

I.B.R., Israeli Biotechnology Research, Ltd.


A perforated partition is mounted in a disposable razor head housing in angular relation to the blade, thereby defining with the housing a refrigerant-receiving chamber disposed in surrounding relation to the blade. A wall is mounted in the housing in spaced, parallel relation to the perforated partition to define an expansion chamber. One or more capped ports are provided in the housing to introduce a refrigerant which is a non-toxic freezable solution typically used to cool lunch boxes.

The present invention relates generally to safety razors which are disposable in whole or in part, and more particularly to the blade-bearing head portions thereof.
For several years, disposable, safety razors have either been equipped with disposable blade bearing heads or have been disposable in their entirety While many advances have been made in blade sharpness and shaving comfort, it is still necessary to replace either the blade head or the entire razor relatively frequently since current blades tend to lose their edge quickly Inevitably, the user runs out of new blade heads or razors and is faced with the inconvenience and expense of traveling to the store and buying more and/or suffering through another dull shave Under the circumstances, the possibility of a blade maintaining its keen edge for a substantially longer period of time attracted the present inventor.
It is well known that a sharp edge wears more slowly at lower temperatures, all else being equal. Accordingly the inventor grew accustomed to placing his disposable razor in the freezer until ready for use. While this technique improved the longevity of the razor's cutting edge, it was impossible to sustain the conventional blade's low temperature during the shaving process. Contact with warm water and the user's face quickly raised the temperature of the thin blade. Thus, the present inventor was faced with the problem of maintaining a low blade temperature throughout the shave.

Disposable refrigerated safety razor head


Method and device for reducing the signal images at the output of a digital/analog converter. In a method for reducing the signal images at the output of a digital/analog converter, a frequency hopping clock generator provides a digital data signal whose data rate is varied according to a frequency hopping method. The digital data signal is converted into an analog signal by a digital/analog converter, the conversion clock being varied according to the frequency hopping method.

A synchronous digital/analog converter (DAC) may be regarded according to FIG. 1 as a circuit which consists of a converter 1 and a holding component 2. This DAC circuit simultaneously implements the following two operations:                converting a number x(nτ) into an electrical variable, for example voltage v(nτ), current i(nτ) or charge q(nτ). The number x(nτ) is usually represented in a binary code. The quantity τ denotes the sampling period, and n denotes the discrete time.        keeping the electrical variable constant over a time interval which corresponds to the sampling period τ or a fraction thereof. The 0th order holding component 2 is used for this. The electrical variable v(t), i(t) or q(t) is provided in a continuous time form at the output of the holding component 2.
FIG. 2A shows a synchronous digital signal in the time domain, i.e. the number x(nτ) plotted against time t. The digital signal can be represented as a sequence of Dirac functions. The sampling period τ corresponds to the inverse of the clock frequency fCLK, i.e. 1/fCLK. In the frequency domain (FIG. 3A), the digital signal is formed by an infinite number of repetitions of the signal spectrum around positive and negative multiples of the clock frequency, k·fCLK, k=0, ±1, ±2, . . . . As usual, the frequency band at d.c. (k=0) is referred to as the baseband and the other frequency bands are referred to as sidebands or signal "images".
In mathematical terms, the conversion of a number into an electrical variable is merely a change of variables, which does not cause any change in the signal spectrum. There are discrete time sample values (x(nτ) and v(nτ), i(nτ), q(nτ)) before and after the conversion.
In contrast to this, the holding operation (holding component 2) transforms the signal from the discrete time domain into the continuous time domain, i.e. it changes the nature of the signal. The signal v(t), i(t) or q(t) exists as a sequence of levels in the time domain (FIG. 2B), whereas it is filtered according to the function sin(πf/fCLK)/(πf/fCLK) in the frequency domain, see FIG. 3B. This function is conventionally referred to as the sinc function. This "free" filtering attenuates mainly the signal images of the signal since, apart from the baseband, they take the value zero at all multiples of the clock frequency fCLK. The attenuation achieved for the signal images is essentially a function of the ratio between the clock frequency fCLK and the bandwidth fB of the signal, i.e. fCLK/fB. Large values of the ratio fCLK/fB cause high attenuation of the signal images which, for a given fixed signal bandwidth fB, necessitates high clock rates. Large values of the ratio fCLK/fB also mean an increase in the flatness of the frequency excursion in the baseband.
Since a digital/analog converter is typically intended to generate the signal without the signal images, a filter 3 is conventionally required so as to attenuate the signal images to a particular required amplitude. The filter is often referred to as an anti-image filter, (AIF) post filter, reconstruction filter, smoothing filter, etc. The filtered signal v*(t), i*(t) or q*(t) at the output of the filter 3 is represented in the time domain (FIG. 20) and in the frequency domain (FIG. 30).
For example, a clock frequency fCLK=13 MHz and a signal bandwidth fB=100 kHz ensures "free" attenuation of 44 dB at the lower edge of the first signal image. At the baseband edge, the flatness of the signal is about 8.45·10−4 dB. With an additional filter 3, it is possible to achieve higher attenuations and flatnesses.
Primarily two approaches have to date been adopted so as to achieve high attenuation of the signal images. The first option is to increase the ratio fCLK/fB and therefore raise the "free" sinc(f) attenuation. In industrial applications, values of the ratio fCLK/fB on the order of several hundred are customary. A disadvantage is the high power use and the great requirement for chip area entailed by an increase in the clock rate. A second option is to use continuous time smoothing filters 3, the order of which is given by a balance between the intended attenuation at the first signal image, the frequency flatness in the baseband and the implementation technology (tuned or untuned). Again, significant costs are incurred with respect to the power consumption, the chip area and the development of such circuits.
At least theoretically, an alternative to the aforementioned options consists in implementing a higher-order holding function at the output of the digital/analog converter. Instead of keeping the electrical variable constant over the clock period τ (keeping the electrical variable constant is referred to as zeroth-order holding), the electrical variable is selected so that it takes information about the preceding values into account when determining the current value (this corresponds precisely to the mode of operation of a filter). It can be shown that higher-order holding components 2 produce higher-order sinck(f) functions with k=2, 3, . . . This concept, however, is very difficult to implement in practice.

Digital-to-analog converter using a frequency hopping clock generator


A throw-away tip of which two principal surfaces each comprises a land surface 5 provided along the periphery thereof, a central surface 7 provided on the inside of the land surface 5, a recess (a chip breaker groove) interposed therebetween, and at least one protrusion 8 that extends from the central surface 7 toward the land surface 5, wherein height of the land surface is made equal to the height of at least the top surface of the protrusion 8 so that at least the top surface of the protrusion of the central surface and the land surface both serve as contact surface.

1. Field of the Invention
The present invention relates to a throw-away style cutting tip used for cutting a cast iron and a steel.
2. Description of Related Art
Throw-away style cutting tips have been used for cutting a cast iron and a steel. Throw-away tips that have modified rake face configurations have been known, such as those having a chip breaker formed in the rake face so as to protect the rake face from being damaged by removed metal chips, and those having a land formed near a cutting edge along the periphery of the rake face in order to prevent damage from cutting resistance or the like.
Throw-away tips having chip breakers and lands formed on both sides have such an advantage as both sides can be used in cutting operations. When such a throw-away tip has the cutting edge on one side worn out, the throw-away tip is turned over so as to carry out cutting operation using the cutting edge on the opposite side. A throw-away tip that uses the edge on either side by turning over is generally designed such that height of the land 25 is lower than a seating surface 27 (middle of the rake face) (h>0) as shown in FIG. 13, in order to prevent the cutting edge from making contact with a tool holder and being damaged (see, for example, Japanese Unexamined Patent Publication No. 8-39306).
However, according to the throw-away tip described above, height of a tip-corner 33 that has the greatest effect on attaching (seating) of the throw-away tip 21 becomes lower. Therefore, when the throw-away tip is used in a cutting operation under conditions involving severe impact, a cutting edge 24 located at the bottom surface (seating surface) of the throw-away tip 21 is lifted. As a result, seating of the throw-away tip 21 becomes insecure thus leading to vibration of the corner 33 during cutting operation. This causes the possibility of the cutting edge 24 located at the bottom surface of the throw-away tip 21 hitting the seating surface of the tool holder intermittently and resulting in breaking (breaking on the back), and/or chattering vibration of the throw-away tip which may cause chipping of the cutting edge 24 engaged in the cutting operation, during cutting.
To avoid such problems, Japanese Unexamined Patent Publication No. 11-277307 discloses a throw-away tip that has so-called full-circumference chip breaker comprising the land 25 and a central surface 27 having similar configuration to the land 25, wherein the land 25 and the central surface 27 are formed at the same height so as to secure the seating of the throw-away tip 21, prevent breaking on the back and reduce the cutting resistance.
The throw-away tip 21 of full-circumference chip breaker, however, also has such a problem that, in case the land 25 of the rake face is damaged due to chipping of the edge 24 or a crater wear during cutting operation with one side of the throw-away tip, the damaged land 25 at a corner portion 33 that has the greatest effect on seating of the throw-away tip 21 cannot provide satisfactory seating surface when the throw-away tip 21 is turned over. As a result, stability of seating is lowered while undesirable movements of the throw-away tip 21 such as lifting and chattering vibration cannot be suppressed and causing such problems as tool damage and/or rough machined surface.
There is also such a problem that, the longer the land surface on one side of the principal surface, the lower the rigidity and more susceptible to deflection. Particularly when used in a cutting operation under conditions involving severe impact, deflection of the land surface causes chattering vibration which may result in damage of the cutting edge. This problem becomes particularly conspicuous in a throw-away tip having diamond shape that has longer on one side line of the principal surface.
The above-mentioned Japanese Unexamined Patent Publication No. 11-277307 describes that cutting resistance is reduced by forming the chip breaker. However, since the chip breaker gradually warps over a wide area, chips tend to entangle when cutting a material of which chips are hard to break such as steel, thus resulting in such a problem that chips are caught between the cutting tool edge and the workpiece thus disabling stable cutting operation. Also in the case of the above-mentioned publication, since the chip breaker groove is wider and accordingly proportion of the contact surface to the entire seating surface is not sufficient, there is a weakness in securely fastening the throw-away tip.
Moreover, simply decreasing the width of the chip breaker groove reduces the effect of warping the chips and breaking them. When the chip breaker is made narrower and deeper, there arises the possibility that chip flow of discharging the chips from the cutting zone is compromised, resulting in such a problem that chips are caught around the cutting tool edge or the chip breaker groove.


A coupling device which is configured such that respective explosives for blasting work are coupled to front and rear sections thereof. The coupling device includes cylindrical bodies, one of the bodies being movable away from or close to another one of the bodies, a partition provided inside a predetermined one of the bodies to divide an inner space of the predetermined body, and an expandable support section provided between the bodies to connect the bodies to each other. The expandable support section forms a cylindrical shape together with the bodies when one body is moved away from the other body and is radially expanded when one body is moved close to the other body. The explosives can be easily inserted into a blasting hole and be positioned in the center of the blasting hole, thereby increasing the efficiency of blasting work.

1. Field of the Invention
The present invention relates, in general, to a coupling device for explosives, and more particularly, to a coupling device which is configured such that respective explosives for blasting work are coupled to front and rear sections thereof.
2. Description of the Related Art
In a variety of civil engineering and construction work including tunneling work, blasting is performed by forming blasting holes in the ground using a rock drill or the like and then inserting explosives into the blasting holes.
The explosives used in this case are coupled together in line via a coupling device, such as a coupling socket.
Referring to FIG. 1 and FIG. 2, a coupling device 10 for explosives of the related art is provided such that respective explosives 1 for blasting work are coupled to the front and rear sections thereof, and has a plurality of support pieces 11 formed on one portion thereof.
According to the design of the coupling device 10 for explosives of the related art, it is intended to insert the explosives 1 into a blasting hole in the state in which the support pieces 11 are pushed back. However, since it is difficult to insert the explosives into the blasting hole due to friction with the inner surface of the hole, at sites, the designed insertion directions are not followed. Rather, the explosives 1 are inserted in the opposite direction because it is easy.
According to the coupling device 10 for explosives of the related art, there is a problem in that the explosives 1 are not located in the center of the blasting hole and the support pieces 11 are too freely movable. Thus, the explosives 1 may be installed in the state in which they are inclined in one direction, thereby degrading the efficiency of the blasting, which is problematic.
In addition, since it is not easy to insert the explosives 1 into the coupling device 10 because of compressed air, the explosives 1 may be easily detached from the coupling device 10. When the explosives are blown up, the tendency of chain explosion (tendency of sympathetic explosion) is degraded. In addition, there is a possibility that the explosives might fail to explode (misfire).
FIG. 3 is a view showing a method of inserting explosives into a blasting hole of the related art.
Referring to FIG. 3, in the related art, the direction in which the explosives is inserted into a blasting hole may be divided into a forward direction and a backward direction depending on the position of the coupling device. However, the directivity of the forward direction or the backward direction is not essential. The forward direction indicates that the coupling device is positioned on the rear end when the explosives are inserted, whereas the backward direction indicates that the coupling device is positioned on the front end when the explosives are inserted.
First, the forward insertion is a method that is generally used at sites. The explosives can be inserted with no difficulties. If impurities are found in the blasting hole during the insertion, there are no significant difficulties in taking the explosives out in order to inserting them again after removing the impurities.
However, in the forward insertion, accurate centering is difficult because the support pieces of the fastening device are folded. In the case of hardening work, the support pieces are folded and thus do not properly play their role, which is problematic.
Next, the backward insertion is a method in which insertion is performed in such a manner that satisfies the purpose of the manufacture of the coupling device. However, since the coupling device is positioned on the front end, it is difficult to insert the explosives into the blasting hole because of the friction between the wall surface of the blasting hole and the support pieces. After the completion of the insertion, the degree to which the support pieces are bent inside the blasting hole is not as severe as in the forward insertion. However, when the hardening work is performed, as in the forward insertion, it is impossible to prevent the support pieces from being bent.
Furthermore, as shown in FIGS. 4A to 4C, when it is difficult to insert the explosives further due to impurities, such as rock or a tree root, in the blasting hole, it is required to take the coupling device from the blasting hole and insert it again after removing the impurities. However, in the backward insertion, when the coupling device is to be taken out, the support pieces 11 are blocked by the wall surface of the blasting hole. It is therefore substantially impossible to take out the coupling device. When the coupling device is forcibly taken out, the support pieces may be damaged or the explosives may be disconnected from each other (see FIGS. 4A and 4B). In FIG. 4A, reference numeral 1a indicates a primary explosive, and reference numeral 1b indicates explosives.
When the insertion is difficult due to the impurities or the like, at sites, as shown in FIG. 4C, the operation of inserting the coupling device is stopped, and the remaining explosive, which has not yet been inserted, is forcibly bent and is pushed into the blasting hole (indicated by reference sign 'A'). In this case, however, sealing work (the operation of closing the blasting hole with soil or sand after the completion of the insertion of the explosives) cannot be properly performed since the space is not sufficient for sealing. In addition, inside the blasting hole, the bottom-hole may not be charged (indicated by reference sign 'B'), such that a blown-out shot (the power of explosion leaks directly through the hole) might occur, thereby failing the blasting work.

Industry Foundation of Chonnam National University


A modular theft-protected display case for rings permits handling and trying-on of a ring which is secured by a strong metallic cord, riveted at the ends which are placed in the axial perforation in a counterweight placed in coinciding grooves which make it impossible to remove the ring from the display case. Rings are situated in openings on a cover of a hollow case. Underneath these holes, inside the case, is a set of strips, each having a vertical line of holes aligned with openings on the cover. These holes have slits at the bottom through which the cord passes. The slits of the holes prevents the ring from being removed either upward, due to the counterweight or downward, due to the ring itself. A separate spring biases each strip to this non-removal position. Each strip has a contacting portion for moving the strip out of its biased position in order to allow a ring to fall through a hole and within the hollow case. This contacting portion is accessible through the back of the case.

Until now, the sale of rings has involved serious difficulties because of the ease with which they can be removed, particularly in department stores, since such sales are public and the potential buyer must have access in order to the try a ring on, all of which makes it possible to remove them. In an attempt to counteract this danger, staff must employ very direct surveillance, thereby raising the cost of sales personnel without offering a high percentage of security against possible theft.
There are at present display cases with security devices which do not allow the public access to try a ring, so that one sales employee must at all times be dedicated to each customer.

Modular theft-protected display case for rings


A reagent vessel cap includes a sealing member for sealing the opening of a vessel body; an pressurizing member linked to a retaining part for sealing the sealing member, for bringing the sealing member in close contact with the opening all the time, wherein when pressure is applied, the pressurizing member lifts the sealing member against the biasing force of itself to open the vessel and, when the pressure is eliminated, the pressurizing member returns to position by the biasing force to close the vessel by the sealing member; and a cap body capable of mounting the sealing member and the pressurizing member to the opening of the vessel body containing a reagent. The reagent is collected using the cap structure.

1. Field of the Invention
The present invention relates to a cap structure of a vessel used to contain a liquid reagent in analytical instruments which are widely employed for chemistry, biology, and medical treatments and to a method for collecting the reagent without the evaporation of the reagent. More particularly, it relates to a cap attached to the opening of the vessel for sealing it, which is opened only when the reagent is collected, thus allowing the contained reagent to be dispensed and to prevent the evaporation and the like of the reagent and to a method for collecting the reagent by using the cap.
2. Description of the Related Art
Reagents for various analytical instruments used for chemical or biological analysis and determination are generally kept in glass or synthetic resin vessels. In order to prevent the evaporation and contamination of the contained liquid reagents, the openings of the vessels are tightly sealed for supply, transportation, and storage. When they are used, in general, the reagent vessels are stored with the seal cap removed in insulating containers at a specified temperature which are provided to the various analytical instruments and the reagents are automatically collected from the vessels with collecting probes attached to the analytical instruments.
Since the vessels in the insulating container are opened in principle, the liquid reagents stored in the such vessels have many problems to be solved such as the risk of contamination, changes in concentration and composition with passage of time due to the evaporation of moisture and volatile components and the outflow of the reagents due to the tipping of the vessels in handling. Accordingly, various means have been proposed for preventing the contamination, evaporation, and deterioration of the reagents.
For example, Patent Document 1, Japanese Unexamined Patent Application Publication No. 5-294354 (claim 1, FIG. 1) proposes a "cap" which includes a top wall having an opening, a skirt without a screw which is made of a soft material, which is constructed to extend downward from the top wall, and slide on the vessel to come in tight engagement therewith, a slim arm having a sealing device for sealing the opening and moving between a sealing position and an unsealing position, and a biasing device for pushing the arm toward the sealing position.
Patent Document 2, Japanese Unexamined Patent Application Publication No. 11-194132 (claim 1), proposes a cap whose lid is capable of being turned laterally upward from a cap sealing position and having an inclined bistable hinge for opening a vessel and one or more catches capable of coming in contact with a device for pressurizing the cap.
Patent Document 3, Japanese Unexamined Patent Application Publication No. 2000-137032 (claim 1), proposes means for preventing the evaporation of a reagent by holding a liquid having a lower specific gravity than that of the reagent in a vessel, which is not mixed to the reagent, and by covering the surface of the reagent with the liquid.
Furthermore, commercially available analytical instruments use a vessel having an elastic thin sealing member serving as an inside plug at the opening, the sealing member having radial slits from the center, wherein when a reagent-collecting probe is moved downward, it is expanded downward and when the reagent-collecting probe is removed, it returns to a horizontal position by elasticity to cover the opening (Architect i2000, made of Abbott Laboratories).
However, the "cap" which has the mechanically openable and closable section as described in Patent Document 1 has a very complicated structure and so requires a device for pressurizing the "cap" which is set to the vessel when applied to various analytical instruments, thus having problems to be solved in practice such as requiring an additional function and production cost for the vessel.
As described in Patent Document 3, the means for preventing the evaporation of a liquid reagent by covering the surface with a liquid having a lower specific gravity than that of the reagent has not the mechanical structure as in the above-described "cap", offering advantages of no contact between the reagent and air and preventing evaporation. However, since the vessel is always opened, the leakage of the reagent due to tipping of the vessel in handling cannot be prevented.
Furthermore, the commercial inside-plug type necessarily requires slits in a thin seal member serving as an inside plug to form clearance in the plug itself, thus having insufficient effects in preventing evaporation of a reagent and air shield, also requires careful operation in the process of attachment of the plug after the removal of the cap so that the reagent is not contaminated, and particularly has the problem of contamination of a collecting probe and also of the reagent due to contact of the reagent-collecting probe with the sealing member.

Reagent vessel cap and method for collecting reagent


A semiconductor memory, such as a static random access memory (SRAM), utilizes short data buses to improve operation speed. The semiconductor memory includes a first group of output ports for receiving data through a first set of bit line pairs, a first data fetching gate and a first data bus for the first set of bit line pairs, disposed along a first long side, a second group of output ports for receiving data through a second set of bit line pairs, and a second data fetching gate and a second data bus for the second set of bit line pairs, disposed along a second long side.

1. Field of the Invention
The present invention relates to a semiconductor memory such as an SRAM (static random access memory) having flip-flop memory cells.
2. Description of the Related Art
FIG. 1 is a plan view schematically showing a conventional SRAM. Numeral 1 denotes a chip proper, 2 an array of memory cells, 3 a bit line pair, 4 a data fetching gate, 5 a data bus, and 60 to 63 output ports (pads). The data bus 5 for bit pairs is connected to output circuits (not shown) corresponding to the output ports 60 to 63. Other pads such as power source pads, are omitted in the figure.
This conventional SRAM is based on DIP (dual in-line package) pin arrangement standards of JEDEC (Joint Electronic Device Engineering Council). The bit line pairs 3 extend in parallel with short sides 7 and 8 of an element forming a plane of the chip 1. The output ports 60 and 61 are disposed along the short side 7 in the vicinity of a long side 9, while the output ports 62 and 63 are disposed along the short side 7 in the vicinity of another long side 10.
Since the storage capacity of this conventional SRAM is not so large, the chip area thereof is not so wide and the output ports 60 and 61 are not so distanced away from the output ports 62 and 63.
In recent years, however, storage capacities of SRAMs are increasing, thereby increasing chip areas and widening distances between output ports. These factors result in elongating data buses, which hinder high-speed operation of the SRAMs.