Patents by Inventor Mark L. Lewis

Mark L. Lewis 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).

  • Optimum fixed angle centrifuge rotor
    Patent number: 5024646
    Abstract: A centrifuge rotor and method for gradient density separation which supports a generally cylindrical volume of sample solution with its axis inclined to the spin axis at an angle which is optimized for maximum separation efficiency while reducing contamination by undesirable centrifugates upon reorientation of the desirable centrifugates. The optimum angle is determined based on the relationship .theta.=Tan.sup.-1 (D/15L).sup.0.5 where D and L are respectively the diameter and length of the cylindrical volume of the sample solution and .theta. is the angle of inclination.
    Type: Grant
    Filed: October 6, 1989
    Date of Patent: June 18, 1991
    Assignee: Beckman Instruments, Inc.
    Inventors: Mark L. Lewis, Thomas D. Sharples, Stephen E. Little
  • Optimum fixed angle centrifuge rotor
    Patent number: RE35071
    Abstract: A centrifuge rotor and method for gradient density separation which supports a generally cylindrical volume of sample solution with its axis inclined to the spin axis at an angle which is optimized for maximum separation efficiency while reducing contamination by undesirable centrifugates upon reorientation of the desirable centrifugates. .Iadd.The sample solution is contained in a centrifuge tube which is closed at its top end by a top portion which is supported by a support cap. The undesirable centrifugates are pelleted to the end corners of the inclined centrifuge tube. The rotor and method are particularly adapted, for example, for separation of nucleic acid into plasmid DNA and chromosomal DNA by density gradient centrifugation. .Iaddend.The optimum angle is determined based on the relationship .theta.=Tan.sup.-1 (D/15L).sup.0.5 where D and L are respectively the diameter and length of the cylindrical volume of the sample solution and .theta. is the angle of inclination.
    Type: Grant
    Filed: June 18, 1993
    Date of Patent: October 24, 1995
    Assignee: Beckman Instruments, Inc.
    Inventors: Mark L. Lewis, Thomas D. Sharples, Stephen E. Little