A Radiation Biology Strategy for Long Term Human Space Exploration
Percival D. McCormack, Professor of Biophysics, Physiology and Bioengineering, University of Illinois at Chicago
Friday, September 23, 2011, 3:30pm
This seminar is part of the Jones Seminars on Science, Technology, and Society series
For flights beyond the earth’s magnetic shield, galactic cosmic radiation (GCR) predominates. This is comprised of high energy (Bev) particles from protons to iron ions. These are biologically very damaging and cause double-strand breaks (DSBs) in DNA, leading to genetic mutation and cancer induction. These effects on humans form the major risk and limitation on long term space exploration. Transport calculations for the GCR spectrum in various metallic shielding materials, like Aluminum, show that after a small decrease in flux in the first thin layers, thicker absorbers do not produce a net reduction of the biological damage. An alternative DNA method must be developed to protect the astronauts. Natural evolution has resulted in a method of repairing DSBs via the direct ligation of the broken DNA ends. This is called the non-homologous end joining (NHEJ) mechanism, and has been identified as the DNA Repair Nanomachine. Five gene products bind directly to the broken DNA ends and have a direct enzymatic role in NHEJ. The proposal here is to modify the NHEJ nanomachine so as to increase the rate of DSB repair and so increase the possible stay-time of astronauts on the Moon and Mars, for example.
About the Speaker
Dr. Percival McCormack received his M.D. in 1978 from Trinity College, Dublin, Ireland and prior to that obtained a Ph.D. in nuclear physics. From 1979 to 2000 he was a US Navy doctor and flight surgeon and for 6 years was assigned to NASA as Chief of Operational Medicine. He also served for 6 years as Chief of Environmental Medicine at the Navy Medical Research Institute, Bethesda, Maryland. In 2000 he took up his present post at the University of Illinois at Chicago. He works on imaging techniques such as ultrasound and MRI. Nanofluids is a topic of special interest for him and he is writing a textbook on “The Vortex, Molecular Spin and Nanovorticity” for Springer-Verlag. He has been a Fellow of the American Association of Aerospace Medicine for many years and recently was appointed to the Advisory Council for the National Institute of Biomedical Imaging and Bioengineering (NIBIB).