Path: utzoo!attcan!utgpu!news-server.csri.toronto.edu!rutgers!aramis.rutgers.edu!athos.rutgers.edu!nanotech From: toms@fcs260c2.ncifcrf.gov (Tom Schneider) Newsgroups: sci.nanotech Subject: Re: STM nuclear reactions Message-ID: Date: 18 Dec 90 18:35:06 GMT Sender: nanotech@athos.rutgers.edu Organization: NCI Supercomputer Facility, Frederick, MD Lines: 48 Approved: nanotech@aramis.rutgers.edu In article landman@eng.sun.com (Howard A. Landman) writes: >In article mike@everexn.com (Mike Higgins) writes: >> There is a sampling problem you all seem to be overlooking: The STM >>doesn't take snapshots, it's this little needle waving around. Even if it is >>scanning the area of say a DNA molecule where a 32P is about to go boom, all >>you will see is one picture whith everything in place, and the next scan will >>show something broken. Big deal. No, it would be the first time somebody saw an 'atomic explosion' at the atomic level. You don't know what might come from that. For one thing, even present day electronics are degraded by the radioactive materials imbedded in their matrix (there was a paper on that in Science (?) sometime before 1987), so learning what kind of local damage occurs could be very important for nanotechnology. And it's an easy experiment that somebody can do TODAY with the right equipment. I realized that one must scan, and that one would not see the actual event. But one would see the damage created. (Assuming the parties are anywhere nearby afterwards!) >My notion was, you scan perhaps once a second to make sure you haven't drifted, >but spend most of the time (more than 98%) hovering over the atom of interest. >That gives you an excellent chance of seeing everything in the Z dimension. >That's why I suggested treating it as an audio-like signal. For video you have >to trade off time resolution to get spatial resolution. The experiment is not practical with one atom, unless the half-life is very short. If it's short then it is hard to prepare the materials without them falling apart before you get to look at them. Since 32P decays with a half life of about 14 days, it hangs around long enough for the experiment to be done. But 32P is convenient also because one can label DNA with it, and that takes only a day. But I DO like the idea of setting up the STM to listen to one phosphate for a MONTH, to 'hear' the actual explosion! I think that would make a nice second experiment, once one had seen the decay by scanning a large population repeatedly. > Howard A. Landman > landman@eng.sun.com -or- sun!landman Tom Schneider National Cancer Institute Laboratory of Mathematical Biology Frederick, Maryland 21702-1201 toms@ncifcrf.gov