Aminopolysaccharide (e.g, Heparin, Glycosamine, Mucopolysaccharide, Chitin, Hyaluronic Acid, Etc.) Patents (Class 106/162.2)
  • Patent number: 7857902
    Abstract: In a method of preparing a non-toxic anti-tacky water paint, nitrocellulose is solubilized in n-butyl acetate to form a nitrocellulose solution, which is then mixed with urea-formaldehyde and water to form a first mixture solution, which is then heated for two to three hours via water at a temperature of 65 to 90° C. so that the first mixture solution is separated into an upper layer of liquid and a lower layer of powder. Next, the upper layer is removed, and ethylene glycol monobutyl ether is added to the lower layer to form a second mixture solution. Then, a non-ionic surfactant is added to the second mixture solution to form a third mixture solution. Finally, the third mixture solution is added to a water-soluble paint to obtain the non-toxic anti-tacky water paint, which may be coated on a container object so that the object can be conveniently transported and stored.
    Type: Grant
    Filed: October 7, 2008
    Date of Patent: December 28, 2010
    Inventor: Yu-Chun Chou
  • Publication number: 20100316715
    Abstract: This invention relates to a cross-linkable chitosan composition comprising chitosan having a degree of deacetylation between 30 and 75%, wherein the chitosan is randomly deacetylated, and a cross-linking agent, wherein the molar ratio of the cross-linking agent to chitosan is 0.2:1 or less based on the number of functional groups in the cross-linking agent and the number of accessible amino groups in the chitosan. The invention also provides a chitosan hydrogel formed therefrom and uses thereof.
    Type: Application
    Filed: October 30, 2008
    Publication date: December 16, 2010
    Inventor: Mats Andersson
  • Publication number: 20100304163
    Abstract: A hydrophilic coating can be applied to virtually any surface to produce a long-lasting, durable antifog effect. The coating includes a molecular-level blend of hydrophilic polymers. The coating can be assembled using a layer-by-layer assembly process.
    Type: Application
    Filed: June 2, 2010
    Publication date: December 2, 2010
    Applicant: Massachusetts Institute of Technology
    Inventors: Nuerxiati Nueraji, Albert J. Swiston, Michael F. Rubner, Robert E. Cohen
  • Publication number: 20100291306
    Abstract: This invention relates to hydroxyalkylated chitosan solution characterized in that a hydroxyalkylated chitosan and an organic acid or its derivative are contained in an aprotic polar solvent. This invention also relates to a coating process of a substrate, which is characterized by a step of causing the hydroxyalkylated chitosan solution to adhere onto a surface of the substrate, and another step of heating the substrate, which has been obtained in the first-mentioned step, at 100° C. or higher for 1 second or longer. This invention can provide a one-pack solution of a chitosan derivative, which is free from crosslinking and stable at room temperature, can form a chitosan coating excellent in waterproofness after heated and dried, and is suited for the coating of a hydrophobic or lipophilic surface. This invention also provides a coating process of a substrate, which makes use of the one-pack solution.
    Type: Application
    Filed: December 19, 2006
    Publication date: November 18, 2010
    Applicant: Dainichiseika Color & Chemicals Mfg Co., LTd
    Inventors: Shinya Tsuchida, Nobuyuki Kobayashi, Takanori Sannan
  • Publication number: 20100239876
    Abstract: There is provided an adhesive comprising chitosan an optionally a crosslinking agent. A method for preparing such an adhesive is also disclosed. A wood-panel made with such an adhesive is also provided. Moreover, a method for manufacturing a wood-based panel is provided. The method comprises preparing a mixture comprising wood, chitosan, optionally a crosslinking agent, and optionally an acid, forming a mat with the mixture, and pressing the mat under heat and pressure so as to obtain the wood-based panel.
    Type: Application
    Filed: February 17, 2010
    Publication date: September 23, 2010
    Inventors: Andre VERVILLE, Yves CHAREST, Martin BEAULIEU, Stephane CHABOT, Richard LEPINE
  • Patent number: 7736423
    Abstract: The present invention relates to an aqueous composition for outdoor, indoor, facade and roof paints having a biocidal action.
    Type: Grant
    Filed: August 23, 2004
    Date of Patent: June 15, 2010
    Assignees: Fraunhofer-Gesellschaft zur Forderung der angewandten Forschung e.V., Bioni CS GmbH
    Inventors: Sven Knoll, Helmut Schmid
  • Publication number: 20100062262
    Abstract: This invention relates to a composition characterized by containing, as essential components, deacetylated chitin and/or a deacetylated chitin derivative, and glyoxylic acid; a solution-containing gel formed from the composition; a water-insoluble chitosan coating; and a material obtained by treating a base material with the composition. According to the present invention, it is possible to provide a chitosan composition, which in a “one-pack” form, has a pot life. Even when dried at room temperature after coating or impregnation of a base material, the chitosan coating can be water-insolubilized with reduced yellowing.
    Type: Application
    Filed: December 27, 2007
    Publication date: March 11, 2010
    Applicant: Dainichiseika Color & Chemicals Mfg. Co., Ltd.
    Inventors: Nobuyuki Kobayashi, Shinya Tsuchida, Takanori Sannan
  • Publication number: 20090257171
    Abstract: This invention relates to a coating formulation for manufacturing an electrode plate, which contains a solution of a hydroxyalkylchitosan and an organic acid and/or its derivative in an aprotic polar solvent, and an active material added to the solution and kneaded with the solution, the electrode plate, a manufacturing process of the electrode plate, a battery, a capacitor, and an undercoating formulation. According to this invention, a coating formulation for manufacturing an electrode plate for a nonaqueous electrolyte secondary battery or an electrode plate for an electric double layer capacitor having excellent adhesion and improved contact resistance between an active material layer and a collector, the electrode plate, its manufacturing process, the battery and the capacitor can be provided.
    Type: Application
    Filed: April 24, 2007
    Publication date: October 15, 2009
    Applicants: KYORITSU CHEMICAL & CO., LTD., DAINICHISEIKA COLOR & CHEMICALS MFG. CO., LTD.
    Inventors: Satoshi Yamazaki, Takaya Sato, Takanori Sannan, Nobuyuki Kobayashi, Shinya Tsuchida
  • Patent number: 7601211
    Abstract: The present invention relates to a process for preparing a porous hybrid comprising zeolite and chitosan and a porous hybrid prepared thereby, in particular, to a process for preparing a porous chitosan-linking compound-zeolite hybrid, which comprises the steps of: (a) forming a linking compound-zeolite intermediate by linking a linking compound to the surface of zeolite; and (b) preparing said chitosan-linking compound-zeolite hybrid by reacting said linking compound-zeolite intermediate with chitosan or a linking compound-chitosan, a porous hybrid prepared thereby, an adsorbent and a method for purifying water.
    Type: Grant
    Filed: June 18, 2004
    Date of Patent: October 13, 2009
    Assignee: Industry-University Cooperation Foundation Sogang University
    Inventors: Kyung Byung Yoon, Eun Ah Lee, Eun Jeon, Yun Jo Lee
  • Patent number: 7485181
    Abstract: A composition-of-matter is provided. The composition-of-matter comprising a chelator moiety-hyaluronan complex bound to a solid support. Also provided are methods of in-situ assessing hyaluronidase activity using such compositions.
    Type: Grant
    Filed: October 7, 2004
    Date of Patent: February 3, 2009
    Assignee: Yeda Research and Development Co. Ltd.
    Inventors: Michal Neeman, Liora Shiftan
  • Publication number: 20080289537
    Abstract: A coating agent which produces a film with photocatalytic properties, comprises composite photocatalyst particles of titanium dioxide and a compound inactive as a photocatalyst, and at least a binder. The photocatalyst particles achieve a ratio of decomposition of acetaldehyde (DWA) values of at least 80%. A BET specific surface area of the composite particles of titanium dioxide and a compound inactive as a photocatalyst is from 10 to 300 m2/g. The composite particles of titanium dioxide and a compound inactive as a photocatalyst are produced by a method comprising the steps of preparing a water based slurry of pH 3 to 5 comprising titanium dioxide, preparing a water based solution comprising a compound inactive as a photocatalyst, and reacting the slurry and the water based solution together at a pH of 4 to 10.
    Type: Application
    Filed: February 14, 2008
    Publication date: November 27, 2008
    Applicant: Showa Denko K.K.
    Inventors: Jun TANAKA, Masayuki Sanbayashi, Yoshinori Ueyoshi, Hiroyuki Hagihara
  • Patent number: 7442730
    Abstract: A colored particle (e.g., a spherical particle) comprising an organic solid component (e.g., a polymer component) and a coloring agent (e.g., an oil-soluble dye, and an organic or inorganic pigment) is produced by eluting a water-soluble auxiliary component comprising at least an oligosaccharide from a composition having a disperse system, in which a particulate dispersed phase comprising the organic solid component and the coloring agent is dispersed in a matrix comprising the auxiliary component. The weight ratio of the polymer component relative to the auxiliary component may be about 55/45 to 1/99. The proportion of the coloring agent may be about 0.001 to 100 parts by weight relative to 100 parts by weight of the organic solid component. Such a process ensures conveniently and industrially advantageous production of a colored particle (e.g., a colored polymer particle) corresponding to the dispersed phase independently of affinity between the dispersed phase and the matrix.
    Type: Grant
    Filed: November 10, 2004
    Date of Patent: October 28, 2008
    Assignee: Daicel Chemical Industries, Ltd.
    Inventor: Hisayoshi Ito
  • Patent number: 7381715
    Abstract: A solid surface material with an antimicrobial agent in a thermoset and/or thermoplastic resin matrix where the antimicrobial agent comprises a chitosan-metal complex.
    Type: Grant
    Filed: November 30, 2004
    Date of Patent: June 3, 2008
    Assignee: E.I. du Pont de Nemours and Company
    Inventor: Subramaniam Sabesan
  • Publication number: 20080110370
    Abstract: A film-forming composition made from a mixture of PVOH, chitosan, and a crosslinking agent is disclosed. Also disclosed are a method of making a film from the composition, a resulting crosslinked film, and a packet made from the film and containing a rinse additive. The composition can be formulated to yield an article such as a film which is soluble only below a predetermined pH threshold.
    Type: Application
    Filed: November 13, 2006
    Publication date: May 15, 2008
    Inventors: Andrew P. Verrall, Solomon E. Brown, Robert A. Schroer, Frank W. Denome, Katherine H. Combs, Larry E. Miller, Anju D. M. Brooker
  • Patent number: 7169423
    Abstract: A virgin chitosan polymer is added to an acid and water solution in an amount sufficient to form an edible composition having a solids content greater than five percent (5%) and a liquid viscosity. The composition is applied to food products, such as fruits, vegetables and nuts, to provide an edible protective coating for the food products. Alternatively, chitosan may be hydrolyzed to a lower molecular weight so that a gel will not be formed when the partially hydrolyzed chitosan is admixed to the acid water solution. An edible wax emulsion and/or a preservative such as sodium benzoate, and/or an adhesion additive such as zinc acetate, and/or a wetting agent, and/or one or more additives from the group consisting of virgin and/or modified carbohydrates, proteins, hydrocolloides, lipids, oils, gums and waxes, natural and/or synthetic, made be added to the composition before it is applied to the food product.
    Type: Grant
    Filed: May 12, 2003
    Date of Patent: January 30, 2007
    Inventors: Carl E. Iverson, Scott P. Ager
  • Patent number: 7147701
    Abstract: New aerogels are disclosed which comprise silica, at least one organic polymer having polar functional groups, and at least one metal ion. Also disclosed are methods for making such aerogels. The present invention further concerns printable objects comprising these aerogels, specifically when the print media are imaged by the absorption of liquid and the spatial localization of pigments or dyes.
    Type: Grant
    Filed: March 20, 2003
    Date of Patent: December 12, 2006
    Assignee: Brown University Research Foundation
    Inventors: William M. Risen, Jr., Shuang Ji, Xiangjun Hu, Ruiyun Zhang
  • Patent number: 7129224
    Abstract: The present invention provides hydrophobic heparin conjugates that are soluble in organic solvents but not in water, a method of preparing them, and a method of using them. Particularly, the present invention provides hydrophobic heparin conjugates that are prepared by covalently binding a polymer to heparin and a hydrophobic agent to the polymer. The hydrophobic heparin conjugates of the present invention maintain a good antithrombogenic effect and are insoluble in water due to their hydrophobicity, so they can be effectively used as coating agents for modifying the surfaces of medical devices.
    Type: Grant
    Filed: November 3, 2000
    Date of Patent: October 31, 2006
    Assignee: Mediplex Corporation, Korea
    Inventors: Young Ro Byun, Hyun Tae Moon
  • Patent number: 7037366
    Abstract: New aerogels are disclosed which comprise silica, at least one organic polymer having polar functional groups, and at least one metal ion. Also disclosed are methods for making such aerogels. The present invention further concerns printable objects comprising these aerogels, specifically when the print media are imaged by the absorption of liquid and the spatial localization of pigments or dyes.
    Type: Grant
    Filed: March 31, 2003
    Date of Patent: May 2, 2006
    Assignee: Brown University Research Foundation
    Inventors: William Risen, Shuang Ji, Xiangjun Hu, Ruiyun Zhang
  • Patent number: 6858312
    Abstract: Use of an aqueous composition, which has been prepared by dissolving (A) dihydroxypropylchitosan and (B) 1,2,3,4-butanetetracarboxylic acid (B) in an aqueous medium, makes it possible to provide articles excellent in hydrophilicity, antibacterial and deodorant activities, touch feeling, antifogging property, paper strength, dyeability, waterproofness, antifouling property and/or the like.
    Type: Grant
    Filed: July 6, 2001
    Date of Patent: February 22, 2005
    Assignees: Dainichiseika Color & Chemicals Mfg. Co., Ltd., Nihon Parkerizing Co., Ltd.
    Inventors: Nobuyuki Kobayashi, Shinya Tsuchida, Takanori Sannan, Kazuya Tanaka, Tetsuo Otsuki, Ryoji Morita
  • Patent number: 6843841
    Abstract: The present invention provides methods of preventing the flow of water or gas or both through a subterranean zone having a high temperature and a depth such that a long pumping time is required to place a sealing composition therein. The methods basically comprise the steps of preparing a polymeric sealing composition comprised of water, a cross-linking agent and a selected water-soluble polymer which reacts with the cross-linking agent and forms a sealing gel which is stable for a desired period of time at the temperature of the zone and has a pumping time before gelation in the presence of the cross-linking agent whereby the composition can be pumped to the depth of the zone and placed therein. Thereafter, the sealing composition is pumped into the zone and allowed to form a sealing gel therein.
    Type: Grant
    Filed: March 12, 2003
    Date of Patent: January 18, 2005
    Assignee: Halliburton Energy Services, Inc.
    Inventors: Baireddy R. Reddy, Larry S. Eoff
  • Patent number: 6830613
    Abstract: A biodegradable sugar-inorganic hybrid composite comprising a sugar or a sugar derivative uniformly dispersed in a matrix of an inorganic oxide, of which degradation products are suitable for recycling use.
    Type: Grant
    Filed: December 24, 2003
    Date of Patent: December 14, 2004
    Assignee: Canon Kabushiki Kaisha
    Inventors: Chieko Mihara, Toyoko Kobayashi, Hiroyoshi Kishi, Toshihiko Takeda, Yoshihiko Kikuchi
  • Publication number: 20040159264
    Abstract: The invention is directed to a method and composition for providing chemically-resistant roughened copper surfaces suitable for subsequent multilayer lamination. In one embodiment, a smooth copper surface is contacted with an adhesion promoting composition under conditions effective to provide a roughened copper surface, the adhesion promoting composition comprising an oxidizer, a pH adjuster, a topography modifier, and a sulfur-containing coating stabilizer. In another embodiment, a smooth copper surface is contacted with an adhesion promoting composition under conditions effective to provide a roughened copper surface, the adhesion promoting composition comprising an oxidizer, a pH adjuster, and a topography modifier. Then, in a subsequent step, the roughened copper surface is contacted with an acid resistance promoting composition.
    Type: Application
    Filed: February 17, 2004
    Publication date: August 19, 2004
    Inventors: Roger F. Bernards, Joseph Stanton Bowers, Benjamin T. Carroll, Alvin A. Kucera
  • Publication number: 20040134384
    Abstract: A biodegradable sugar-inorganic hybrid composite comprising a sugar or a sugar derivative uniformly dispersed in a matrix of an inorganic oxide, of which degradation products are suitable for recycling use.
    Type: Application
    Filed: December 24, 2003
    Publication date: July 15, 2004
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Chieko Mihara, Toyoko Kobayashi, Hiroyoshi Kishi, Toshihiko Takeda, Yoshihiko Kikuchi
  • Publication number: 20040129173
    Abstract: A composition is provided consisting of an aqueous solution comprising at least one natural polysaccharide or a derivative thereof and at least one polymeric polyamino compound, the composition being capable of forming a film when applied onto a substrate. The invention also involves a method for temporary protection of a substrate surface from environmental influence using such composition.
    Type: Application
    Filed: March 1, 2004
    Publication date: July 8, 2004
    Inventor: Sigfrid Svensson
  • Patent number: 6602336
    Abstract: New aerogels are disclosed which comprise silica, at least one organic polymer having polar functional groups, and at least one metal ion. Also disclosed are methods for making such aerogels. The present invention further concerns printable objects comprising these aerogels, specifically when the print media are imaged by the absorption of liquid and the spatial localization of pigments or dyes.
    Type: Grant
    Filed: August 13, 2001
    Date of Patent: August 5, 2003
    Assignee: Brown University Research Foundation
    Inventors: William M. Risen, Jr., Shuang Ji, Xiangjun Hu, Ruiyun Zhang
  • Publication number: 20030143420
    Abstract: A composition and process for inhibiting the corrosion of metallic substrates is revealed. The process utilizes an aqueous treatment solution comprising chitosan which has been reacted with an additive selected from the group consisting of phosphorus-containing compounds and sulfur-containing compounds and mixtures thereof. More preferably, the phosphorus-containing compound is a phosphonic acid and the sulfur-containing compound is a mercapto, thio, or thienyl containing compound or a mercapto functional silane. The composition and process are particularly useful in providing corrosion protection for aluminum and aluminum alloys.
    Type: Application
    Filed: December 23, 2002
    Publication date: July 31, 2003
    Inventor: Gerald Wojcik
  • Publication number: 20030124189
    Abstract: A polymer blend is prepared by dissolving chitosan and a second polymer in an acidic aqueous solution to form an aqueous polymer blend, dehydrating said aqueous polymer blend, and recovering said polymer blend. The second polymer may be selected from the group consisting of polyether glycols including polyethylene glycols; cellulose esters including cellulose acetate; poloxamers; polysaccharides including dextran and guar; polyvinylpyrrolidones; polyvinyl alcohols; and mixtures or copolymers thereof. These polymer blends swell in an acidic environment and deswell in a more neutral or basic environment. This technology is valuable for the dispensing of biologically active material or drugs into a surrounding environment, especially the environment as is found in the gastrointestinal tract.
    Type: Application
    Filed: December 20, 2002
    Publication date: July 3, 2003
    Inventors: Gaylen M. Zentner, Jong-Seok Bark, Feng Liu
  • Publication number: 20030078394
    Abstract: By irradiating 60Co &ggr; ray to chitin/chitosan, chitin/chitosan having high molecular weight is separated or decomposed into low molecular weight chitin/chitosan. A method of producing an osteoconduction substance comprises the steps of irradiating 60Co &ggr; ray to chitin/chitosan to produce low molecular weight chitin/chitosan; preparing chitosan sol by dissolving low molecular weight chitin/chitosan in an acidic aqueous solution to obtain a chitosan acidic aqueous solution and kneading the chitosan acidic aqueous solution and apatite powder; and neutralizing the chitosan sol by the use of a neutralizing agent.
    Type: Application
    Filed: October 23, 2002
    Publication date: April 24, 2003
    Applicant: MATSUMOTO DENTAL UNIVERSITY
    Inventor: Michio Ito
  • Publication number: 20020160098
    Abstract: A nucleic acid coating composition including a polyanion bound, directly or through one or more intermediates, to a medical device surface, with a condensate comprising a polycation and nucleic acid bound to the polyanion, devices incorporating such coating compositions, and methods for making. In one embodiment, a silyl-heparin complex is provided, bound to a medical device surface by hydrophobic interaction with the silyl moiety, with a polycation and nucleic acid condensate bound to the heparin by electrostatic interaction.
    Type: Application
    Filed: January 22, 2002
    Publication date: October 31, 2002
    Inventors: Paul O. Zamora, Ray Tsang, Shigemasa Osaki
  • Patent number: 6419830
    Abstract: A polymeric resin is disclosed in the form of beads or particles having a coating thereon which renders the resin blood compatible. The resin comprises divinylbenzene monomer which has a porosity, pore size, and surface area suitable for absorbtion of unhealthy components of blood, such as &bgr;-2-microglobulin.
    Type: Grant
    Filed: September 27, 2001
    Date of Patent: July 16, 2002
    Assignee: The Dow Chemical Company
    Inventors: Robert M. Strom, Daniel J. Murray
  • Patent number: 6344077
    Abstract: An aqueous cellulose solution containing chitosan and/or chitosan derivatives, or alternatively alginic acid and/or alginic acid derivatives, and water-soluble and antibacterial rayon fiber produced from the cellulose solution. The aqueous cellulose solution includes a first component containing at least one selected from the group consisting of alkali cellulose and cellulose derivatives, and a second component containing at least one selected from the group consisting of soluble chitosan and chitosan derivatives, or alternatively at least one selected from the group consisting of soluble alginic acid and alginic acid derivatives, wherein the first and second components are homogeneously mixed without phase separation. The rayon fiber obtained by wet-spinning the aqueous cellulose solution shows antibacterial property or flame-retardancy depending on the composition of the cellulose solution, and water-solubility or water-resistance depending on the composition of a coagulating bath.
    Type: Grant
    Filed: February 2, 2000
    Date of Patent: February 5, 2002
    Inventor: Young-keun Hong
  • Patent number: 6338801
    Abstract: A polymeric resin is disclosed in the form of beads or particles having a coating thereon which renders the resin blood compatible. The resin comprises divinylbenzene monomer which has a porosity, pore size, and surface area suitable for absorbtion of unhealthy components of blood, such as &bgr;-2-microglobulin.
    Type: Grant
    Filed: December 22, 2000
    Date of Patent: January 15, 2002
    Assignee: The Dow Chemical Company
    Inventors: Robert M. Strom, Daniel J. Murray
  • Patent number: 6302950
    Abstract: The invention relates to an aqueous solution or dispersion with high shellac content. The aqueous shellac solution or dispersion is characterized in that it has a pH value of 2 to 4.2, and contains: 1 to 60% wt. shellac; 0.1 to 3% wt. of at least one water-soluble film former; 0.1 to 1% wt. of at least acid-resistant gel former; and water bringing the total to 100% wt. In accordance with the invention, the solution is produced by the following method: particle-shaped shellac is added to an aqueous solution and homogenized by stirring at 10 to 1500 rev/min., at a temperature of 5 to 20° C. The aqueous solution has a pH value of 2 to 4.2 and contains at least one water-soluble film former and at least one acid-resistant gel former. The shellac solution or dispersion can be used in the paint and varnish industry, the food industry and in cosmetics.
    Type: Grant
    Filed: January 31, 2000
    Date of Patent: October 16, 2001
    Assignee: Lancaster Group GmbH
    Inventors: Karin Golz-Berner, Leonhard Zastrow
  • Patent number: 6303046
    Abstract: New aerogels are disclosed which comprise silica, at least one organic polymer having polar functional groups, and at least one metal ion. Also disclosed are methods for making such aerogels and for making them as substantially transparent objects. In addition, gas detectors, liquid and gas absorbing objects, and optical devices made using these aerogels are disclosed. The present invention concerns optical elements which are substantially transparent and exhibit low refractive indices. The invention also relates to the optical properties of the metal-containing ions, the silica and polymer which they comprise. The optical elements can be passive or they can be active in response to electromagnetic radiation. The invention further relates to detectors of reactive and absorbate gases based on the physical changes exhibited by the aerogels upon reacting with or absorbing such gases.
    Type: Grant
    Filed: August 7, 1998
    Date of Patent: October 16, 2001
    Inventors: William M. Risen, Jr., Shuang Ji, Xiangjun Hu, Ruiyun Zhang
  • Patent number: 6241812
    Abstract: Acid-stable and cationic-compatible reticulated bacterial cellulose compositions, containing co-agents and/or cationic surfactants, that are useful rheological modifying agents and stabilizing agents for suspensions, emulsions and foams, and their methods of preparation are disclosed.
    Type: Grant
    Filed: February 5, 1999
    Date of Patent: June 5, 2001
    Assignee: Pharmacia Corporation
    Inventors: Barbara A. Smith, George T. Colegrove, Walter G. Rakitsky