Slashdot Mirror
Sense of Smell Tied To Quantum Physics?
SpaceAdmiral writes "A controversial theory that proposes that our sense of smell is based not on the shape of the molecules that enter our nose but on their vibrations was given a boost recently when University College London researchers determined that the quantum physics involved makes sense. The theory, proposed in the mid-1990s by biophysicist Luca Turin, suggests that electron tunneling initiates the smell signal being sent to the brain. It could explain why similarly shaped molecules can have very different smells, and molecules with very different structures can smell similar." Turin has now formed a company to design odorants using his theory, and claims an advantage over the competition of two orders of magnitude in rate of discovery. The article concludes, "At the very least, he is putting his money where his nose is."
I am going to be very skeptical of this and would not be tossing any money into a private company to study this just yet. The olfactory system is well capable of distinguishing many small molecules, even those that are very similar using a variety of well known and well understood processes just as in the immune system. Look, a Nobel prize was awarded back in the 30's for the discovery that IGGs can recognize even racemic molecules such as L and D forms of glycine even and the olfactory literature is just as rich. The biggest problem however, with the UCL approach is that it completely ignores years of cortical, subcortical and psychophysics data. Furthermore, there is no effort or model in their work that might explain how the signals would be transduced into cortical/subcortical signals or how they account for potential noise in the system. Their claim that signals can be translated through tunneling in a biological system which likely swamps those potential signals with noise is what really troubles me.
I am not saying that they should not do it, or that they are absolutely wrong, as it is possibly interesting. Rather all I am saying is my eyebrows are raised at their claims.
Visit Jonesblog and say hello.
I remember reading about this guy (probably on the Slashdots) years ago, and I hoped that this would be one of those rare cases of someone who is rejected by the "scientific community" and then goes on to success. There are so many scientists out there that end up on dead-end roads (I'm looking at you, Cold Fusion), that it's nice to have a reminder that there's still reason to explore.
For proof that success is the best revenge, just check out the company's product list. They're making a killing by creating replacements for aromatic allergens.
I guess one thing that made me think he was on to something was his reaction to the scientific community's snub -- one response I recall likened a quantum-mechanical sense of smell to "food being processed in the stomach by nuclear reactions". He did NOT go around telling the world that the scientist cabal was out to get him, or that the perfume cartel was conspiring to suppress his work. He simply went about building a successful business by *using* his hypothesis to create and license useful, concrete products.
You know, I think this is why we have patents in the first place. Not so megacorporations can trademark "business practices" -- if I hear another insurance company or bank describe their latest gimmick with a "patent pending" disclaimer I'm gonna puke. It's so some little guy on the right track can take a risk and come out on top.
Stressed? Me? Of course not. Stress is what a rubber band feels before it breaks, silly.
Does that mean that Schroedinger's cat may or may not smell like a corpse if it's dead?
A poet once said, "The whole universe is in a glass of wine." We will
probably never know in what sense he meant that, for poets do not write to
be understood. But it is true that if we look at a glass of wine closely
enough we see the entire universe. There are the things of physics: the
twisting liquid which evaporates depending on the wind and weather, the
reflections in the glass, and our imagination adds the atoms. The glass is
a distillation of the earth's rocks, and in its composition we see the
secrets of the universe's age, and the evolution of stars. What strange
array of chemicals are in the wine? How did they come to be? There are the
ferments, the enzymes, the substrates, and the products. There in wine is
found the great generalization: all life is fermentation. Nobody can
discover the chemistry of wine without discovering, as did Louis Pasteur, the
cause of much disease. How vivid is the claret, pressing its existence into
the consciousness that watches it! If our small minds, for some
convenience, divide this glass of wine, this universe, into parts --
physics, biology, geology, astronomy, psychology, and so on -- remember that
nature does not know it! So let us put it all back together, not forgetting
ultimately what it is for. Let it give us one more final pleasure: drink it
and forget it all!
- Richard P. Feynman, The Feynman Lectures on Physics, v. 1, p. 3-10
(This lecture is also one of the six lectures featured in a book &
audio edition entitled "Six Easy Pieces")
Besides if you are 30, by the time you are 70 it will be 2076 and if you consider all the progress made from 1906 to 1946 it will be at least interesting.
Wow, a post from the future! What's it like in 2036?
Electrons, photons, and protons are all merely models to explain in tangible terms what the **** is going on down there, so I become skeptical when these terms are utilized to explain/demonstrate quantum mechanics.
Um, okay, we don't know everything about these particles, but all of those things are real things very much like we describe them -- we can count electrons, photons, and protons, and in the latter case we know they are comprised of smaller things called "quarks" that when combined correctly behave very much like the little ball we call the "proton". That's as real as anything. Quantum mechanics describes the behavior of electrons, so I'm confused as to why you would be skeptical that electrons are used to explain quantum mechanics. The topics are rather intricately linked.
I'm quite certain that there are layers upon layers beyond what we know, but at this time we don't know of any way to go deeper than the electron. Hence you're basically asking for something to be described in terms of knowledge that doesn't exist yet, which is impossible.
The enemies of Democracy are
This theory is "revolutionary" because biochemists use classical simulations. Quantum mechanics is very difficult to apply to such large systems in practice but these molecules definitely are governed by quantum mechanics like all molecules.
Save the bandwidth. Don't use sigs!
I'm a graduate student in Computer-Aided Drug Design, and as part of my degree I did a research proposal on prediction of smell with computers.
a tes/2004/illpres/
Richard Axel and Linda Buck received their Nobel Prize in 2004 for Physiology or Medicine for "for their discoveries of odorant receptors and the organization of the olfactory system". Note that this is not *only* for the discovery of the receptors, but also for the *way they work*. There are hundreds of receptors in mammals (almost 1,000 in mice, about 330 in humans) that have different selectivities for different odorant molecules and act combinatorially, that is, that the signal perceived by the brain is the result of the combination of receptors activated by the odorant. Given the large number of receptors, and that any number can be activated by an odorant, the variety of smells is huge, and on the other hand the promiscuity of the receptors allows for a chance of 2 dissimilar molecules having the same smell...
Some literature I suggest for someone interested:
- Nobel Prize illustrated presentation: http://nobelprize.org/nobel_prizes/medicine/laure
(see also the Nobel Lectures therein)
- Unpredictability of smell: Sell, C. S. Angew. Chem., Int. Ed. 2006, 45, 6254-6261.
I really think that the system of smell is already quite strongly explained by this theory, that also follows the classical binding+activation of receptors that drives traditional biochemistry and drug design.
I'm still surprised that some theoretical chemist/physicist didn't do QM calculations to prove the tunneling, and publish it in a leading peer-reviewed journal, if the theory is so sound...