NASA Photo ID: STS042-231-006     File Name: 10064494.jpg

Film Type: 35mm CN                Date Taken: 01/30/92

Title: STS-42 Phase Partitioning Experiment (PPE) closeup taken onboard OV-103

Description:

STS-42 Phase Partitioning Experiment (PPE), an International Microgravity 
Laboratory 1 (IML-1) experiment, is documented in a closeup taken onboard 
Discovery, Orbiter Vehicle (OV) 103.  Phase partitioning is a very
effective  technique used by biochemists and cell biologists to obtain
fairly pure  cells.  Cells are separated and collected in a mixture of two
immiscible  liquids (fluids that tend not to mix) by their surface
characteristics.  In  the PPE, investigators feel they will be able to
separate closely related  cells because cell density and convection flows
are not factors in the phase  partitioning process in space.  They also
hope to study other factors that  influence the process.  Phase
partitioning is used to separate biological  materials such as bone marrow
cells for cancer treatment.