Patents by Inventor Yasuhiko Kojima

Yasuhiko Kojima has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5372911
    Abstract: A process of forming a super high-contrast negative image is disclosed, which comprises the steps of imagewise exposing a negative-working silver halide photographic material comprising a support having thereon one or more hydrophilic colloidal layers, at least one of the one or more hydrophilic colloidal layers being a negative-working silver halide emulsion layer, and then developing the photographic material with a developer containing an aminophenol derivative developing agent and a reductone compound in the existence of an organic compound having a negative reduction potential. A negative-working silver halide photographic material and a photographic developer being used for the image-forming process are also disclosed.
    Type: Grant
    Filed: June 11, 1992
    Date of Patent: December 13, 1994
    Assignee: Dainippon Ink and Chemicals, Inc.
    Inventors: Naoki Obi, Yasuhiko Kojima, Yasuo Shigemitsu, Jun Takeuchi, Kiyoshi Suematsu
  • Patent number: 5362621
    Abstract: A direct positive silver halide photographic material and a method for forming a high contrast image using the same are disclosed, in which a pre-fogged direct positive silver halide emulsion layer contains a salt of a nitrogen-containing compound having at least one pyridine nucleus and at least one pyridinium nucleus. The photographic material, after imagewise exposure, is developed with an alkaline developer containing a developing agent, preferably a reductance compound. The photographic material provides high contrast characteristics having a gamma exceeding 10.
    Type: Grant
    Filed: August 18, 1993
    Date of Patent: November 8, 1994
    Assignee: Dainippon Ink and Chemicals, Inc.
    Inventors: Naoki Obi, Kiyoshi Suematsu, Yasuhiko Kojima, Masatoshi Katayama, Yasuo Shigemitsu
  • Patent number: 5284733
    Abstract: A silver halide photographic material is disclosed. The photographic material comprises a support having coated thereon one or more hydrophilic colloidal layers, at least one of the hydrophilic colloidal layers being a negative working silver halide emulsion layer, wherein said silver halide emulsion layer or another hydrophilic colloidal layer contains a water-soluble polymer or copolymer having a quaternary ammonium salt in a repeating unit. The process for forming a high contrast negative image using the photographic material is also disclosed.
    Type: Grant
    Filed: October 1, 1991
    Date of Patent: February 8, 1994
    Assignee: Dainippon Ink and Chemicals, Inc.
    Inventors: Yasuhiko Kojima, Naoki Obi, Yasuo Shigemitsu, Kiyoshi Suematsu
  • Patent number: 5275915
    Abstract: A developer for light-sensitive material capable of processing in common a negative-working light-sensitive lithographic printing plate and a positive-working light-sensitive printing plate as well as a developing agent-containing type silver halide photographic material, is disclosed. The developer comprises an alkali agent, an anionic surface active agent, an antifoggant for a silver halide photographic material, and an alkylene oxide addition product (molecular weight of from 130 to 1200) of an aromatic amine or an aralkyl amine, and has pH of the range of from 11.5 to 13.5.
    Type: Grant
    Filed: June 2, 1992
    Date of Patent: January 4, 1994
    Assignee: Dainippon Ink and Chemicals, Inc.
    Inventors: Yasuhiko Kojima, Yasuo Shigemitsu
  • Patent number: 5217842
    Abstract: A process of forming superhigh-contrast negative images is disclosed. The process comprises the steps of imagewise exposing a substantially surface latent image-type silver halide photographic material which is spectrally sensitized with a sensitizing dye and then developing said photographic material with a developer, wherein said photographic material contains a heterocyclic thione compound and said developer comprises (a) an aminophenol derivative developing agent, (b) a reductone compound, (c) a quaternary ammonium salt, and (d) a compound represented by formula (I): ##STR1## wherein R.sub.1, R.sub.2 and R.sub.3, which may be the same or different, each represents a hydrogen atom, a nitro group, a halogen atom, or a cyano group, and wherein said development processing is carried out in the existence of at least one kind of a polyalkylene oxide or a derivative thereof. The process provides negative images of superhigh contrast having gamma over 10 substantially free from appearance of pepper.
    Type: Grant
    Filed: September 18, 1991
    Date of Patent: June 8, 1993
    Assignee: Dainippon Ink and Chemical, Inc.
    Inventors: Yasuhiko Kojima, Naoki Obi, Yasuo Shigemitsu
  • Patent number: 4882261
    Abstract: Novel dot enhancing compositions are disclosed for use in high contrast negative-working image-forming systems. The compositions include compounds of the general formula: ##STR1## wherein R.sub.1 is an aromatic group, A is a substituted or unsubstituted aromatic nucleus, and the two carboxyl groups specifically depicted in general formula (I) are each bound to a different carbon atom of said aromatic nucleus.The dot enhancing compositions may be incorporated into a silver halide photographic emulsion or into another hydrophilic colloid layer of a photographic material, or into a developing solution or, alternatively, into both. The dot enhancers of the invention improve density and contrast of images formed, as well as providing a harder, smoother, better formed dot for use in letter press and offset lithography.
    Type: Grant
    Filed: June 27, 1988
    Date of Patent: November 21, 1989
    Assignees: Polychrome Corp., Dainippon Ink & Chemicals, Inc.
    Inventors: Yasuhiko Kojima, John Pilot, Burton H. Waxman
  • Patent number: 4871540
    Abstract: A biologically active substance comprising a kind of glycolipid having an elemental analysis (%) of H: 5.20-5.40, C: 42.55-44.17 and N: 3.94-4.08 and a molecular weight of about 30,000-10.sup.6 is obtained by extracting the tissue of a plant of maize (Zea mays Linne) or a variant thereof by extracting the tissue with water and recovering the desired active substance from the resultant extract. This substance is capable of inhibiting the formation of IgE antibodies and promoting the formation of IgG and IgM antibodies, and moreover exhibits various biological activities such as interferon-inducing activity, polyclonal B lymphocite activating activity, mitrogenic activity, adjuvant activity and anti-tumour activity. Thus, this substance is expected to be useful for preventing and treating, for example, aesthema, rhintitis, B-type hepatitis, AIDS and other allergic diseases and immunological insufficiency.
    Type: Grant
    Filed: July 17, 1986
    Date of Patent: October 3, 1989
    Assignee: Yasuhiko Kojima
    Inventors: Yasuhiko Kojima, Sadao Tamamura
  • Patent number: 4724196
    Abstract: A lith-type silver halide photographic material comprising a tetrahydro-1,3,5-triazine-2-thione derivative and a polyalkylene oxide derivative.
    Type: Grant
    Filed: March 2, 1987
    Date of Patent: February 9, 1988
    Inventors: Tadao Shoji, Yonosuke Tsuka, Naoki Obi, Yasuhiko Kojima, Yasuo Shigemitsu
  • Patent number: 4533547
    Abstract: A novel antiviral antibiotic AM-2722 is described represented by the molecular formula C.sub.19 H.sub.26 NO.sub.3 Cl, and having the following physicochemical properties:(1) specific rotary power: [.alpha.].sub.D.sup.20 -0.5 (C-1, chloroform);(2) the UV spectrum shown in FIG. 1; and(3) the IR spectrum shown in FIG. 2.Also described is a process for producing the antiviral antibiotic AM-2722, wherein a microorganism of Streptomyces which has the ability to produce the antibiotic AM-2722 is cultured aerobically in a nutrient medium and the antibiotic AM-2722 accumulated in the medium and the microorganism cells is recovered.
    Type: Grant
    Filed: May 11, 1981
    Date of Patent: August 6, 1985
    Assignee: The Kitasato Institute
    Inventors: Satoshi Omura, Akira Nakagawa, Hiroshi Hashimoto, Yasuhiko Kojima, Yuzuru Iwai, Ruiko Oiwa, Atsushi Hirano
  • Patent number: 4469685
    Abstract: A process for producing interferon inducers from the plants, comprising extracting a water-soluble interferon inducer with water from the tissue of a plant selected from the genera Atractylodes, Lonicera, Plantago, Lithospermum, Ligusticum, Cnidium, Bupleurum, Notopeterygium, Heracleum, Aralia, Panax, Polygala, Sophora, Euchresta, Astragalus, Sinomenium, Stephania, Cocculus, Cimicifuga, Rheum, Gastroida, Asparagus, Pinellia, Evoida and variants thereof capable of producing said interferon inducer at a temperature of from ambient to the boiling point of the extraction mixture for a period sufficient to extract the major portion of said interferon inducer present in the plant tissue, forming a supernatant, fractionating the supernatant to yield fractions containing the major portion of said interferon inducer in the supernatant and recovering said interferon inducer therefrom. Preferably, the fractionation may be effected by ultrafiltration.
    Type: Grant
    Filed: May 5, 1983
    Date of Patent: September 4, 1984
    Assignee: The Kitasato Institute
    Inventors: Yasuhiko Kojima, Seishi Konno, Sadao Tamamura, Takashi Hashimoto
  • Patent number: 4456597
    Abstract: An interferon inducer isolated from the plant tissue, having an elemental analysis of H: 6.54.+-.0.3% C: 41.9.+-.0.3%, N: 2.39.+-.0.3% and P: 0.28.+-.0.03% and a molecular weight of from about 100,000 to about 3,000,000 (mainly about 200,000 to about 1,000,000) and containing as main constituents amino acids, sugars and phosphoric acid. This substance is believed to be a homogeneous polymer of protein and sugars, containing phosphoric acid. This substance has an excellent interferon inducing activity and low toxicity and is significantly active against various viruses. The interferon inducer may be produced by extracting a substance having interferon inducing activity from the tissue of a plant of the genus Carthamus of the family Compositae or a variant thereof containing said active substance and recovering the active substance from the extract thereby obtained.
    Type: Grant
    Filed: August 6, 1981
    Date of Patent: June 26, 1984
    Assignee: The Kitasato Institute
    Inventors: Yasuhiko Kojima, Seishi Konno, Takashi Hashimoto
  • Patent number: 4442087
    Abstract: An interferon inducer isolated from the plant tissue, having an elemental analysis of H:7.4.+-.0.4%, C: 45.6.+-.0.4%, N: 13.5.+-.0.4%, P: 2.8.+-.0.3% and a molecular weight of from about 100,000 to about 3,000,000 (mainly about 200,000 to about 1,000,000) and containing as main chemical constituents amino acids and phosporic acid. This substance is believed to be a homogeneous polymer of protein and phosphoric acid.This substance has an excellent interferon inducing activity and low toxicity and is significantly active upon various viruses. This interferon inducer may be produced by extracting a substance having interferon inducing activity from the tissue of a plant of the genus Artemisia of the family Compositae or a variant thereof containing the said active substance with water and recovering the active substance from the extracted solution. The recovery may preferably be effected by ultrafiltration.
    Type: Grant
    Filed: July 13, 1981
    Date of Patent: April 10, 1984
    Assignee: The Kitasato Institute
    Inventors: Yasuhiko Kojima, Seishi Konno, Sadao Tamamura, Takashi Hashimoto, Nobuyuki Shibukawa
  • Patent number: 4440761
    Abstract: A process for producing an interferon inducer by extracting a substance having interferon inducing activity with water from the tissue of a plant selected from the genus Carthamus and variants thereof containing the said active substance to give an extracted solution, forming a supernatant from the extracted solution, fractionating the supernatant to yield fractions containing a major portion of the said active substance present in the supernatant and recovering the said active substance therefrom, characterized by fractionating the supernatant to yield fractions containing the said active substance having a molecular weight of from about 10,000 to about 200,000. Preferably the seed may be used as the tissue and the fractionation may be effected by ultrafiltration using a membrane capable of fractionating substances having the above-mentioned molecular weight.
    Type: Grant
    Filed: August 6, 1981
    Date of Patent: April 3, 1984
    Assignee: The Kitasato Institute
    Inventors: Yasuhiko Kojima, Seishi Konno, Takashi Hashimoto
  • Patent number: 4421746
    Abstract: An interferon inducer is produced by extracting a tissue of a plant belonging to the Gound family selected from the group consisting of Benincasa, Cucurbita, Citrullus, Cucumia, Lagenaria, Luffa, Mormordica, Tricsanthes and their variants by water extraction at a temperature of from ambient to the boiling point of the extraction mixture, forming a supernatant from the extracted solution, fractionating the supernatant to yield fractions containing the interferon inducer and recovering same.
    Type: Grant
    Filed: June 28, 1982
    Date of Patent: December 20, 1983
    Assignee: The Kitasato Institute
    Inventors: Yasuhiko Kojima, Sadao Tamamura, Seishi Konno, Takashi Hashimoto
  • Patent number: 4419349
    Abstract: An interferon inducer isolated from the plant tissue, having an elemental analysis of H: 8.5-8.7 %, C: 48.8-49 %, N: 6.3-6.5 % and P: 1.0-1.1 % and a molecular weight of from about 100,000 to about 3,000,000 (mainly about 200,000 to about 1,000,000) and containing as main constituents amino acids, sugars and phosphoric acid. This substance is believed to be a homogeneous polymer of protein and sugars, containing phosphoric acid. This substance has an excellent interferon inducing activity and low toxicity and is significantly active against various viruses. The interferon inducer may be produced by extracting a substance having interferon inducing activity from the tissue of a plant of the genus Perilla of the family Labiatae or a variant thereof containing said active substance and recovering the active substance from the extract thereby obtained. Preferably, the extraction may be effected with water and the recovery may be effected by ultrafiltration.
    Type: Grant
    Filed: May 22, 1981
    Date of Patent: December 6, 1983
    Assignee: The Kitasato Institute
    Inventors: Yasuhiko Kojima, Seishi Konno, Sadao Tamamura, Yoshimoto Sano, Nobuyuki Shibukawa, Takashi Hashimoto