Patents by Inventor George C. Na

George C. Na 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: 5470583
    Abstract: This invention discloses a composition comprised of nanoparticles having a non-ionic surfactant as a surface modifier adsorbed on the surface thereof and a charged phospholipid as a cloud point modifier associated therewith, which cloud point modifier is present in an amount sufficient to increase the cloud point of the surface modifier. A preferred non-ionic surfactant surface modifier is a poloxamine or tyloxapol, and preferred charged phospholipid cloud point modifiers include dimyristoyl phosphatidyl glycerol. This invention further discloses a method of making nanoparticles having a non-ionic surfactant as a surface modifier adsorbed on the surface and a charged phospholipid as a cloud point modifier associated therewith, comprised of contacting said nanoparticles with the cloud point modifier for a time and under conditions sufficient to increase the cloud point of the surface modifier.
    Type: Grant
    Filed: May 10, 1994
    Date of Patent: November 28, 1995
    Assignee: Eastman Kodak Company
    Inventors: George C. Na, Natarajan Rajagopalan
  • Patent number: 5447710
    Abstract: The present invention is directed to a composition comprised of nanoparticles containing an x-ray diagnostic compound, having a high molecular weight nonionic surfactant as a surface modifier adsorbed on the surface thereof and a cloud point modifier associated therewith.The present invention is also directed to a method for making nanoparticles comprising(i) contacting said nanoparticle containing an x-ray diagnostic compound with a high molecular weight nonionic surfactant for a time and under conditions sufficient to form a nanoparticle with the surfactant adsorbed on the surface thereof; and(ii) contacting the so treated nanoparticle with a cloud point modifier for a time and under conditions sufficient to form a nanoparticle containing an x-ray diagnostic compound, having a nonionic surfactant as a surface modifier adsorbed on the surface thereof and a cloud point modifier associated therewith.
    Type: Grant
    Filed: May 13, 1994
    Date of Patent: September 5, 1995
    Assignee: Eastman Kodak Company
    Inventors: George C. Na, Natarajan Rajagopalan
  • Patent number: 5352459
    Abstract: This invention discloses a composition comprised of nanoparticles having a purified polymeric surfactant as a surface modifier adsorbed on the surface thereof and a cloud point modifier associated therewith, which cloud point modifier is present in an amount sufficient to increase the cloud point of the surface modifier. Preferred purified polymeric surfactants are purified polyalkyleneoxide substituted ethylenediamine surfactants. A preferred cloud point modifier is polyethylene glycol. This invention further discloses a method of making nanoparticles having a purified polymeric surfactant as a surface modifier adsorbed on the surface and a cloud point modifier associated therewith, comprised of contacting said nanoparticles with the cloud point modifier for a time and under conditions sufficient to increase the cloud point of the surface modifier.
    Type: Grant
    Filed: December 16, 1992
    Date of Patent: October 4, 1994
    Assignee: Sterling Winthrop Inc.
    Inventors: Kenneth R. Hollister, David Ladd, Gregory L. McIntire, George C. Na, Natarajan Rajagopalan, Barbara O. Yuan
  • Patent number: 5346702
    Abstract: This invention discloses a composition comprised of nanoparticles having a surface modifier adsorbed on the surface thereof and a non-ionic cloud point modifier associated therewith, which cloud point modifier is present in an amount-sufficient to increase the cloud point of the surface modifier. A preferred surface modifier is a poloxamine such as Tetronic 908, and preferred non-ionic cloud point modifiers include polyethylene glycol, propylene glycol, ethanol, hydroxypropylcyclodextrin and/or glycerol. This invention further discloses a method of making nanoparticles having a surface modifier adsorbed on the surface and a non-ionic cloud point modifier associated therewith, comprised of contacting said nanoparticles with the cloud point modifier for a time and under conditions sufficient to increase the cloud point of the surface modifier.
    Type: Grant
    Filed: December 4, 1992
    Date of Patent: September 13, 1994
    Assignee: Sterling Winthrop Inc.
    Inventors: George C. Na, Natarajan Rajagopalan
  • Patent number: 5336507
    Abstract: This invention discloses a composition comprised of nanoparticles having a non-ionic surfactant as a surface modifier adsorbed on the surface thereof and a charged phospholipid as a cloud point modifier associated therewith, which cloud point modifier is present in an amount sufficient to increase the cloud point of the surface modifier. A preferred non-ionic surfactant surface modifier is a poloxamine or tyloxapol, and preferred charged phospholipid cloud point modifiers include dimyristoyl phosphatidyl glycerol. This invention further discloses a method of making nanoparticles having a non-ionic surfactant as a surface modifier adsorbed on the surface and a charged phospholipid as a cloud point modifier associated therewith, comprised of contacting said nanoparticles with the cloud point modifier for a time and under conditions sufficient to increase the cloud point of the surface modifier.
    Type: Grant
    Filed: December 11, 1992
    Date of Patent: August 9, 1994
    Assignee: Sterling Winthrop Inc.
    Inventors: George C. Na, Natarajan Rajagopalan
  • Patent number: 5326552
    Abstract: The present invention is directed to a composition comprised of nanoparticles containing an X-ray diagnostic compound, having a high molecular weight nonionic surfactant as a surface modifier adsorbed on the surface thereof and a cloud point modifier associated therewith.The present invention is still further directed to a method for diagnostic imaging for use in medical procedures comprising administering to the body of a test subject in need of an X-ray an effective contrast producing amount of a composition comprised of nanoparticles containing an X-ray diagnostic compound, having a high molecular weight nonionic surfactant as a surface modifier adsorbed on the surface thereof and a cloud point modifier associated therewith.
    Type: Grant
    Filed: December 17, 1992
    Date of Patent: July 5, 1994
    Assignee: Sterling Winthrop Inc.
    Inventors: George C. Na, Natarajan Rajagopalan
  • Patent number: 5298262
    Abstract: This invention discloses a composition comprised of nanoparticles having a surface modifier adsorbed on the surface thereof and an anionic or cationic surfactant as a cloud point modifier associated therewith, which cloud point modifier is present in an amount sufficient to increase the cloud point of the surface modifier. A preferred surface modifier is tyloxapol. Preferred anionic surfactants are dioctylsulfonesuccinate, sodium dodecyl sulfate and sodium oleate. Preferred cationic surfactants are dodecyltrimethylammonium bromide and cetrimide tetradecyl ammonium bromide. This invention further discloses a method of making nanoparticles having a surface modifier adsorbed on the surface and an anionic or cationic surfactant as a cloud point modifier associated therewith, comprised of contacting said nanoparticles with the cloud point modifier for a time and under conditions sufficient to increase the cloud point of the surface modifier.
    Type: Grant
    Filed: December 4, 1992
    Date of Patent: March 29, 1994
    Assignee: Sterling Winthrop Inc.
    Inventors: George C. Na, Natarajan Rajagopalan
  • Patent number: 5094946
    Abstract: Materials containing both chromium and protein and treated by processes which include the steps of: combining a material to be treated (i.e. containing both chromium and protein) with sufficient water to produce a mixture having from about 75 wt. % water to about 95 wt. % water, and an additive which both provides an alkaline pH and provides calcium or magnesium as an enzyme cofactor. The mixture is thereafter held at a temperature of from about 60.degree. C. to about 75.degree. C. for a period of time of from about 0.5 hour to about 4 hours. Subsequently, at least one enzyme is utilized to hydrolyze the protein, thus producing a product containing solubilized hydrolyzed protein and insoluble chromium. After separation of the soluble fraction from the insoluble fraction, the chrome in the insoluble residue may be recycled into the pickling or tanning process, and the essentially chrome-free protein hydrolyzate is potentially useful as an ingredient in feeds, fertilizers, and cosmetics.
    Type: Grant
    Filed: February 8, 1990
    Date of Patent: March 10, 1992
    Assignee: The United States of America as represented by the Secretary of Agriculture
    Inventors: Maryann M. Taylor, Edward J. Diefendorf, George C. Na, William N. Marmer