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Superconducting DNA
Mr_Dyqik writes "Alik Kasumov of the Laboratoire de Physique des Solides in France and co-workers have shown that DNA molecules act as ohmic conductors above 1K and that below this temperature they can superconduct. This could allow the creation of self assembling superconducting circuits. (A Y Kasumov et al 2001 Science 291 280). The story is on PhysicsWeb."
For a commercial vendor, try American Superconductor. Their web page is at http://www.amsuper.com . They sell many devices based on superconductors, and some raw materials as well (under "Products & Solutions", "Electric Power Applications").
Umm.. Seems to me that almost anything that acts as a conductor would superconduct at that temperature. Problem is, it takes so much energy to get to that temperature, it's not worth it.
We don't need to worry about specialist areas like quantum computing - I'm only setting an upper limit on size here, based on the AI section in Drexler's "Engines of Creation"
Vik :v)
Vik
As far as self assembling superconducting circuits, DNA is probably not the right way to go. Currently the rules of DNA superhelix assembly are way to complex to easily predict. Plus, at super conducting temperatures, there is no way that the DNA is going to be capable of self assembly. (the experiment was conducted with DNA molecules of length 2-3, 10sh and 20-30 bases.)
Furthermore, just the process of supercooling DNA will probably denature molecules of any interesting length and structure. Finally, once all this is done, how in the world do you compute with just a string of DNA at that cold of a tempurature? I wouldn't think that it would be any more interesting in ability to compute than a bucky tube.
Don Armstrong -".naidnE elttiL etah I"
http://www.donarmstrong.com
I don't disagree with you. I mean what kind of dummy would think of looking for pornography on the web?
But you're posting to the wrong article bud.
You meant to post to the article about the worst jobs on the net and this about cooling your body to within 1 degree of absolute zero to create a self assembling super computer. In fact you and some linuxchix could get together and create a beowulf cluster out of yourselves.
Science is great huh?
...when cooled below 1K become superconducting?
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Why not make your own? If you have acess to a chemistry lab you almost certainly have the chemicals to do so.
:o]
First measure out the proper stoichiometric amounts of chemicals to satisfy the final Y BA2 Cu3 O7-X formula. Your amounts could be: Yttrium Oxide, Y2O3 11.29 grams, Barium Carbonate, BaCO3 39.47 grams, and Cupric Oxide, CuO 23.86 grams for one example.
Then grind together and heat the mix to 950 degrees Celsius for about a day. After you let it cool grind it again and heat back up to about 1000C if you can, pass pure oxygen over the sample and now cool it very slowly at no more than 100C/hour. If you like press the final powder into a pellet.
Voila, your very own superconductor. I did it over a weekend once it's really easy and kinda fun once you get it to work. Get some liquid nitrogen from your local welding shop and nab one of the superstrong samarium cobalt magnets from an old pair of headphones to do the meissener demo.
- "Hear that?! The percolations are imminent! Cease your ingress!"
Most superconductors work between temperatures of 1mK and 4K, and it's not difficult to work at this temperature. Obviously it's not a lot of use for building MagLev trains or those sorts of uses for superconductivity, but it is very useful for building superconducting electronics, which have very different properties to semiconducter electronics. Self asssembly is one of the major goals of nanoelectronics and engineering, because it's far too hard to use lithography techniques at these scales (you have to use x-ray lithography, and that doesn't exist yet). So the idea is you mix up these enzymes, DNA strands etc. and give them the right heat treatments, and out pops your circuit. At the moment nanoelectronics uses electron microscopes and atomic force microsopes to make circuits, which is very slow.
This doesn't require laser cooling in anyway, as Liquied He cryostats can get to 30mK, Laser cooling isn't required unless you want to hit 1nK, and only really works on a few atoms at a time.
The actual advance is that it could become easier to create superconducting circuits that can do a job that normal silicon can't. e.g superconducting circuits can operate quite easily in the 100 GHz region, where all silicon circuits have to laid out as waveguides etc.
Most of the useful effects in superconducting circuits come from the presence of Shapiro steps and other microwave resonances in Josephson junctions and their ilk.
Man, you thought names like "Athlon" and "Duron" were wierd...just wait until they start naming them after all of your friends after they find our how nice their DNA is...
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While interesting in an academic sense, such a discovery is rather trivial in a practical sense. Superconductivity itself has a number of astonishing uses that can sometimes look like magic, but they're only useful when we can get them to occur at useful temperatures. Unfortunately, cooling something to 1K will require something along the lines of laser cooling in order to achieve, and this turns out to not be very practical. Superconductors with a very low critical temperature cannot conduct much current before they exceed their critical energy level and "go normal".
Laser cooling only works for gases. 1K is usually achieved by first cooling using liquid Helium, then using various tricks to go a few degrees lower. Releasing pressure, or realignment of magnetic fields can all cause temperature drops sufficient to reach 1K, or even lower. Laser cooling is used to reach temperatures far lower than 1K.
Useful superconductors are more in the line of HTC's, high temperature superconductors. The simplest of these are the superconductors that work when cooled to the order of 70 degrees Kelvin (-200C) by liquid nitrogen (which is cheaper than beer). If I recall correctly, the highest published HTC was around 175K, which is only 100 degrees below freezing. I've heard rumors of higher temperature superconductors, but haven't seen any referreed publications of results yet. Keep your eyes peeled, we'll see room-temperature superconductors within the lifetimes of most slashdotters.
That might not be possible. Many physicists now question if RTSCs are possible, because the thermal energy of the lattice might break apart the delicate electron-electron pairing. Certainly, there is a lot of territory to cover, like strained crystal lattices, doped bucky tubes and the like, but don't get your hopes up. Also, most HTSCs are brittle, difficult to manufacture, very expensive, and often toxic.
To be fair to lower temperature superconductors, I believe the maglev train in Japan uses a lower temperature superconductor cooled by liquid helium, which is somewhere down on the order of 10K.
Most modern experiments involve liquid Nitrogen temperatures, or no superconductors at all. It's just cheaper. Liquid Helium is expensive, and requires complex insulation systems.
Superconductors aren't too useful for their property of not conducting current, since they have a critical maximum current level anyway. They are mostly used for their diamagnetic properties (they repel magnetic flux lines). This is the basis for how an MRI works, or for how super-fast magnetic trains work.
Their maximum current capacity is huge, but unlike copper, if you stay under the maximum, superconductors can transfer the current with zero loss, even at lower voltages. They are already in use at several powerplants for short-haul, high-current lines, etc... I've heard of at least one powerplant that uses a superconducting ring (inductor) to smooth out demand surges.
It'll be like in that science fiction story (sorry, I cannot remember the author of the story, but it was in book one of an anthology that was published by Polaris, a division of White Wolf Publishing) where people convicted to die were required to donate their organs to health officials... they started changing stuff like parking tickets to get a death sentence!
They'll do that to DNA now! they're going to need our nuclei to copy their DNA strands, and they'll make it so if we breathe wrong, badmouth someone, or use Macintoshes we'll be convicted and they'll take our nuclei!
Join the "Save the Nuclei" movement now, before it's too late for humanity!!!
"Titanic was 3hr and 17min long. They could have lost 3hr and 17min from that."
IBM had PL/1, with syntax worse than JOSS,
And everywhere the language went, it was a total loss...
Edmund Scientific sells kits including the magnet and type II superconducting wafer which will let you demonstrate the Meisner Effect with cheap liquid nitrogen as the coolant. They don't sell the liquid nitrogen, you have to scare that up yourself.
Brackets contain world's first nanosig, highly magnified:[.]
While this is fascinating stuff, it'd be even cooler (if you'll excuse the pun)if we could make variant DNA that superconducts at higher temperatures :-)
Anyway, one slightly offtopic question about superconductivity and the high-temperature superconductors that caused all the fuss back in the 1980's: what happened? Did we reach another temperature plateau? Was it still at liquid-nitrogen-required temperatures?
Any sufficiently advanced technology is indistinguishable from a rigged demo
--Andy Finkel (J. Klass?)
The concept of using DNA for structural purposes is about as different from genetics as using mortar is to building seashells.
The DNA is only sequenced to stick to itself, not to create or emulate any gene. It is quite likely that the "genetic" content of DNA used in this manner is garbage in the genetic context. The prime requirement in fact is that the DNA used for structural purposes will not interact with anything other than the target it is to join to.
Vik :v)
Rememebr that we're talking a very, very small device here. To cool a Pentium chip of several square centimetres area to 1K would take a reasonable amount of machinery, say about 6 filing cabinet drawers worth.
:v)
But to do the same to a volume less than 1 cubic millimetre? That could be done inside a desktop case. 1 cubic mm of DNA is a hell of a lot of circuitry. At a molecular scale you can reproduce the functionality of the human brain in a few cc's - if you can keep it cold.
Vik
Superconductors were discovered in the early 1900s by Onnes (in mercury). In the 80s they discovered the so called type 2 superconductors which have much higher critical temperature, i.e. they are superconducting at higher temperatures, making it possible to use cheap liquid nitrogen for cooling instead of liquid helium. Type 2 superconductors are not metals (or have impurities) and are usually some kind of copper oxide. They have much different properties than Type 1 (which are usually pure metals).
________
Does anyone actually have a Java program designed to control air traffic, or for the operation of a nuclear facility?
While interesting in an academic sense, such a discovery is rather trivial in a practical sense. Superconductivity itself has a number of astonishing uses that can sometimes look like magic, but they're only useful when we can get them to occur at useful temperatures. Unfortunately, cooling something to 1K will require something along the lines of laser cooling in order to achieve, and this turns out to not be very practical. Superconductors with a very low critical temperature cannot conduct much current before they exceed their critical energy level and "go normal".
Useful superconductors are more in the line of HTC's, high temperature superconductors. The simplest of these are the superconductors that work when cooled to the order of 70 degrees Kelvin (-200C) by liquid nitrogen (which is cheaper than beer). If I recall correctly, the highest published HTC was around 175K, which is only 100 degrees below freezing. I've heard rumors of higher temperature superconductors, but haven't seen any referreed publications of results yet. Keep your eyes peeled, we'll see room-temperature superconductors within the lifetimes of most slashdotters.
To be fair to lower temperature superconductors, I believe the maglev train in Japan uses a lower temperature superconductor cooled by liquid helium, which is somewhere down on the order of 10K.
Superconductors aren't too useful for their property of not conducting current, since they have a critical maximum current level anyway. They are mostly used for their diamagnetic properties (they repel magnetic flux lines). This is the basis for how an MRI works, or for how super-fast magnetic trains work.