Patents by Inventor Herman W. Levin

Herman W. Levin 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).

  • Evanescent wave background fluorescence/absorbance detection
    Patent number: 4945245
    Abstract: It is proposed to increase the utility of intracellular fluorescence and absorbance measurements for control of fermentation and cell culture by correcting on-line for background fluorescence of the media, also to be able to measure the fluorescence or absorbance of the fluid media in the presence of suspended cells or particles. The measurements could be extended to measure the optical properties of other fluids which contain suspended particles. This invention uses the characteristics of the evanescent wave at the surface of an optic waveguide. The wave penetrates into the less dense medium only to about the depth of about 1/2 wavelength. The thickness of media swept by the evanescent wave is much less than the size of a cell, thereby essentially separating the fluorescence or absorbance of the media from that of the cells.
    Type: Grant
    Filed: July 14, 1988
    Date of Patent: July 31, 1990
    Inventor: Herman W. Levin
  • Electrochemical determination of hematocrit
    Patent number: 4699887
    Abstract: A method for measuring hematocrit is provided. An electrochemically detectable marker is measured before and after the ratio of red cell volume to plasma volume is decreased. The measured concentrations are used in a mathematical formula to determine hematocrit value.
    Type: Grant
    Filed: March 24, 1986
    Date of Patent: October 13, 1987
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: Scot D. Abbott, Herman W. Levin, Robert K. Kobos, Henn Kilkson, Dale R. Peterson
  • Optical detector cell
    Patent number: 4681443
    Abstract: An optical cell provides a measuring chamber which is L-shaped with an absorbance optical path lying along the horizontal leg of the L. A second optical path is provided transverse to the absorbance path and sized to permit the passage of radiation into the entire L-shaped chamber. The exit slit for the cell receives radiation from the entire vertical leg of the L and may serve as the entrance slit to a photometer.
    Type: Grant
    Filed: May 8, 1985
    Date of Patent: July 21, 1987
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: David T. Bach, Roger A. Gruenke, Herman W. Levin
  • Electrochemical determination of hematocrit
    Patent number: 4605628
    Abstract: A method for measuring hematocrit is provided. An electrochemically detectable marker is measured before and after the ratio of red cell volume to plasma volume is decreased. The measured concentrations are used in a mathematical formula to determine hematocrit value.
    Type: Grant
    Filed: October 4, 1984
    Date of Patent: August 12, 1986
    Assignee: E. I. du Pont de Nemours and Company, Inc.
    Inventors: Scot D. Abbott, Herman W. Levin, Robert K. Kobos, Henn Kilkson, Dale R. Peterson