Talk:Vibration theory of olfaction

"controversial"

The article is OBVIOUSLY hardly biased against Vibrational theory, repeating on many occasions that is "controversial" : 20 year ago - science claimed couple to hundred thousand different smells human nose and human brain can differentiate; at the end of first quarter of XXI century - number is thousands of billions (!) - so it is impossible that only (up to) 400 smell receptors, in couple of thousand of each of them, in an absolute number, in average nose (total number of receptors in the nose is 2 x 3-4 millions, so approx. 7 millions in average, up to 10-15 M max. in total) - can recognize thousand of billions of them, in INFERIOR human nose (comparing to mouse, dog, elephant ...) - without taking into account, at least partially, vibrational theory of smell. — Preceding unsigned comment added by 217.75.200.50 (talk) 08:13, 19 April 2024 (UTC)

"or hypothesis" ?

Isn't the "or more precisely, hypothesis" a little childish? It's every bit the theory that shape is but with more concrete evidence and better predictive power. Suggest a little more professional introduction?Cdubulous 04:10, 22 October 2007 (UTC)

Removed "some evidence supports shape theory" since no evidence I can find anywhere supports shape theory. If someone could come up with a convincing structure-odor relationship paper to cite on the shape theory page, it would make more sense to assert it here. It's far too vague right now. The Vosshall & Keller paper does not support vibration and is consistent with a shape-based theory, but it does not confirm any particular prediction of shape theory, especially since one of their findings, that a mixture of guiacol and benzaldehyde does not produce a vanilla illusion, in fact contradicts the weak shape theory, since guiacol and benzaldehyde together constitute the shape of vanillin and a receptor system recognizing pieces in a mixture should feel all the bits of vanillin. Brooklyntbone (talk) 17:34, 9 December 2007 (UTC)

History of Science (in progress?)

I'm wondering if the article should include some notation about the status of this topic in relation to paradigm shift, where the shape hypothesis is the old paradigm that is being challenged. I'm most impressed by similarities to the history of plate tectonics, which was presented long ago, then ignored for many years, but which is now almost universally accepted, even though the precise mechanisms are still not fully understood.

By the way, I was trying to find links on the Web, but Google repeatedly led me to the Wikipedia article on plate tectonics, even though there is nothing there that seemed related to the other aspects of my queries. I guess the conclusion there is that Google works in mysterious ways?

Shanen (talk) 00:42, 28 January 2009 (UTC)

Optical Isomers & Deuterated compounds (again)

So people supposedly can distinguish full deuterated benzaldehyde but not acetophenone? It strikes me that the two are going to have vastly different experiences with deuterium exchange in the nose, and that likely one will see compounds with both hydrogen isomers present at different rates, also that perhaps the C-D vs. C-H aldehyde group's resonance ratios ought to be more significant than the CD3 vs. CH3 resonance ratios because the ratios of the masses of the subgroups are not at all the same... (1:2 vs 15:18).

Also, the concept of a "nose receptor" making shape matter was arguably demonstrated by Turin himself by using a solvent to render the effects of shape meaningless; by inactivating a mechanism and achieving the result he sought, he showed that mechanism is indeed significant. Of course, another approach may be to use some sort of snot in the analytic solution in order to take into account the effect of sterosensitive hydrogen bonding with the solute - optical isomers of one compound can bind with optical isomers in quite different ways depending on how they match, which should somewhat shift their resonance.Zaphraud (talk) 08:19, 13 May 2009 (UTC)

Turin's original paper reports the acetophenone test, and he claims that subjects were able to distinguish the results. The entire reason for using fully deuterated acetophenone is that it does not have any hydrogens capable of being easily exchanged. 204.52.215.2 (talk) 01:37, 15 October 2009 (UTC)

Turin's original paper actually reports an effect in the exact same three tests where Keller and Vosshall report none. Turin reports a guaiacol/benzaldehyde mixture was found to smell like vanillin. Keller and Vosshall found it does not. Turin reports that it is a well-established fact that different chain length aldehydes smell differently. Keller and Vosshall found people unable to distinguish them in a double-blind test. Turin found that D8-acetophenone smells differently from acetophenone. Keller and Vosshall report it does not. The fact that Turin reported three effects corresponding to his theory and Keller and Vosshall managed to replicate none is a major blow.-204.52.215.2 (talk) 01:46, 15 October 2009 (UTC)

The smell of outer space

I considered deleting the paragraph about outer space smelling like fried steak and hot metal. I think further research into its relevance is required. Steven Pearce is quoted as attributing the "hot metal" smell of outer space to "a high-energy vibration in the molecule."

How can we find out what sort of high-energy vibration he was referring to? The molecules in a very hot piece of metal would be vibrating at a very high frequency. That vibration seems categorically another topic from the protein vibrations in the olfactory mucosa.

Pearce may have been trying to recreate the smell by heating up pieces of metal to very high temperatures and asking the astronauts to sniff them, not by exactingly studying the nose's receptor mechanism. Does someone want to write to him and ask?

Also, the concept of outer space having a smell might be a little misleading/sensationalist. It's really the smell of space travel, i.e. the inside of a spaceship. You'd die if you tried to sniff the vacuum of space directly.

70.112.120.193 (talk) 16:24, 15 August 2010 (UTC)

I've deleted the Steven Pearce quote, since it seems out of context and irrelevant to that section. It appears to be just a casual comment, not a big statement taking sides in a scientific debate. He is not a basic researcher on smell receptor activation or considered a major proponent or part of the history of the theory; he seems to run a fragrance compounding firm. It would be nice for someone elsewhere eventually to follow up on the questions posed above, but original research is verboten on Wikipedia. Anyway, here is the relevant bit I deleted in case someone would like to discuss a better place for it:

• On October 17, 2008, NASA contractor Steven Pearce, a fragrance expert and manufacturer, was quoted as saying that he believes the distinctive smell of outer space, which he describes as a mixture of "fried steak" and "hot metal," may be due in large part to "a high-energy vibration in the molecule."

Londonbroil (talk) 00:00, 17 February 2011 (UTC)

References

Vibratory receptors

It is widely accepted that the eyes interpret electro-magnetic waves in the visible spectrum and that the ears work with mechanical waves. Heat - another sort of wave - is also detectable and highly developed in some reptiles.

It seems that proteins fold by quantum entanglement or some such inter-atomic mechanism. Nature is known to be a highly conservative innovator - could it be that all these receptor proteins (e.g. maybe G-protein–7-coupled receptors?) are somehow related to the same mechanism involved in neuron impulse transmission and protein folding?

Just a silly thought - mouths of babes and seniles in second infancy - maybe? Saludos, Timpo (talk) 19:40, 18 June 2018 (UTC)