Code of Conduct
Page 1 of 2 1 2 LastLast
Results 1 to 60 of 76
  1. #1

    Default New study contradicts Luca Turin's theory?

    That's what it sounds like to me, but it's a bit technical. Thoughts? Here it is:

    Shakespeare wrote “a rose by any other name would smell as sweet.” But would it if the molecules that generate its fragrance were to change their shape?

    That’s what Dr. Kevin Ryan, Assistant Professor of Chemistry at The City College of New York (CCNY) and collaborators in the laboratory of Dr. Stuart Firestein, Professor of Biology at Columbia University, set out to investigate. Their findings, reported December 22 in the journal “Chemistry & Biology,” shed new insight into how our sense of smell works and have potential applications in the design of flavors and fragrances.

    When odor-producing molecules, known as odorants, pass through the nose, they trigger intracellular changes in a subset of the approximately 400 different varieties olfactory sensory neurons (OSN) housed in the nose’s internal membrane tissue, Professor Ryan explained. The unique reaction pattern produced, known as the olfactory code, is sent as a signal to the brain, which leads to perception of odors.

    Professor Ryan and his team wanted to learn how these receptor cells respond when odorants change their shape. They studied the odorant octanal, an eight-carbon aldehyde that occurs in many flowers and citrus fruits. Octanal is a structurally flexible molecule that can adapt to many different shapes by rotating its chemical bonds.

    The researchers designed and synthesized eight-carbon aldehydes that resembled octanal, but had their carbon chains locked by adding one additional bond. These molecules were tested on genetically engineered OSNs known to respond to octanal. This work was done in Professor Firestein’s laboratory at Columbia.

    The aldehyde molecules that could stretch to their greatest length triggered strong activity in the OSNs. However, those molecules whose carbon chains were constrained into a U shape blocked the receptor and left the cell unable to sense octanal.

    “Conformationally constrained odorants were more selective in the number of OSNs they activated,” Professor Ryan noted. “The results indicate that these odorant molecules might be able to alter fragrance mixture odors in two ways: by muting the activity of flexible odorants present in a mixture and by activating a smaller subset of OSNs than chemically related flexible odorants. This would produce a different olfactory code signature.”

    Olfactory receptors belong to the G-protein coupled receptor (GPCR) class of proteins, a family of molecules found in cell membranes throughout the body. Professor Ryan pointed out that half of all commercial pharmaceuticals work by interaction with proteins within this family. Thus, the findings could also have applications to GPCR drug design, as well.

    This can be found at: http://www.sciencedaily.com/releases...1222163053.htm

  2. #2
    A Site For Sore Eyes

    kbe's Avatar
    Join Date
    Nov 2006
    Location
    The Big Blue Marble
    Posts
    17,491
    Post Thanks / Like
    Blog Entries
    1

    Default Re: New study contradicts Luca Turin's theory?

    I am going to spend a night in a Holiday Inn Express and then re-read that article.
    Deep in the dark your kiss will thrill me
    Like days of old. Lighting the spark of love that fills me
    with dreams untold..--Twilight Time

  3. #3

    Default Re: New study contradicts Luca Turin's theory?

    The work discussed does not so much contradict Turin's theory as it does ignore it. It is widely accepted that Turin's theory is not correct. The 2004 Nobel Prize in Physiology or Medicine was awarded to Axel and Buck for their discoveries of "odorant receptors and the organization of the olfactory system". This work invalidates Turin's theory.
    http://nobelprize.org/nobel_prizes/m...004/press.html
    "The sense of smell long remained the most enigmatic of our senses. The basic principles for recognizing and remembering about 10,000 different odours were not understood. This year's Nobel Laureates in Physiology or Medicine have solved this problem and in a series of pioneering studies clarified how our olfactory system works. They discovered a large gene family, comprised of some 1,000 different genes (three per cent of our genes) that give rise to an equivalent number of olfactory receptor types. These receptors are located on the olfactory receptor cells, which occupy a small area in the upper part of the nasal epithelium and detect the inhaled odorant molecules.

    Each olfactory receptor cell possesses only one type of odorant receptor, and each receptor can detect a limited number of odorant substances. ..."

    The scientists in the Science Daily article take the results of the 2004 Nobel prize work as a given.
    "When odor-producing molecules, known as odorants, pass through the nose, they trigger intracellular changes in a subset of the approximately 400 different varieties olfactory sensory neurons (OSN) housed in the nose’s internal membrane tissue, Professor Ryan explained. The unique reaction pattern produced, known as the olfactory code, is sent as a signal to the brain, which leads to perception of odors."
    Last edited by dcampen; 26th December 2008 at 10:35 PM.
    All these moments will be lost in time, like tears in rain.

  4. #4
    irish's Avatar
    Join Date
    Jun 2007
    Location
    MI, USA.
    Posts
    2,540
    Post Thanks / Like

    Default Re: New study contradicts Luca Turin's theory?

    I thought Luca's theory had been refuted years ago. Too bad for him, but at least he tried. I bet he could have earned the Nobel prize* for that if he had been right. Georg von Bekesy did win it for his studies on the human ear, and he was wrong, too. Oh well.

    *EDIT: oh, they did win it. That must have sucked for LT. I guess he can now pull a Stephen Hawkins and become famous for his witty and scientific best seller books.
    Last edited by irish; 26th December 2008 at 10:57 PM.
    Shameless Plug: Sales thread with Roses Musk, Rose Poivree, and others.
    Looking for lot of samples of female fragrances.

  5. #5
    the_good_life's Avatar
    Join Date
    Jun 2006
    Location
    Friedberg (Hessen)
    Posts
    5,568
    Post Thanks / Like

    Default Re: New study contradicts Luca Turin's theory?

    It's been a while since I read about this, but I'm confused. Do Axel and Buck discuss anywhere how individual receptor cells identify the molecules they are "responsible for?" If I recall correctly, Turin's point was that the mechanism is based not on molecular shape recognition but vibration measurement. Is that question indirectly resolved by their research, because to this layman it doesn't seem to be addressed in the nobel summary?

    Just dug up on wikipedia:http://en.wikipedia.org/wiki/Vibration_theory
    "A 1996 paper by Turin revived the theory by proposing a mechanism, speculating that the G-protein-coupled receptors discovered by Linda Buck and Richard Axel were actually measuring molecular vibrations using inelastic electron tunneling, rather than responding to molecular keys that work by shape alone.[2]"
    My Wardrobe
    II est de forts parfums pour qui toute matière/Est poreuse. On dirait qu'ils pénètrent le verre.

  6. #6

    Default Re: New study contradicts Luca Turin's theory?

    From what I remember of the Burr book, there are undeniable facts that simply cannot be reconciled with the accepted theory, and thus it can't be valid (though this doesn't mean LT is right, but at least he has created actual molecules with his theory). I think dcampen is right and that they just ignored LT. However, I also think there are some BNers who know more about this than I do, so I hope they post responses here.

  7. #7

    Default Re: New study contradicts Luca Turin's theory?

    From what I remember of the Burr book, there are undeniable facts that simply cannot be reconciled with the accepted theory
    Not that I remember.

    The one thing the Burr book was good at was manufacturing artificial controversy in order to sell copies of the book. The scientific exposition was terrible. I thought the most egregious "error" was repeatedly and continually confounding the mythical "shape" theory of odor perception with the currently accepted odorant receptor theory of Axel and Buck in order to set up a straw man.
    All these moments will be lost in time, like tears in rain.

  8. #8

    Default Re: New study contradicts Luca Turin's theory?

    It's been a while since I read about this, but I'm confused. Do Axel and Buck discuss anywhere how individual receptor cells identify the molecules they are "responsible for?" If I recall correctly, Turin's point was that the mechanism is based not on molecular shape recognition but vibration measurement. Is that question indirectly resolved by their research, because to this layman it doesn't seem to be addressed in the nobel summary?

    Just dug up on wikipedia:http://en.wikipedia.org/wiki/Vibration_theory
    "A 1996 paper by Turin revived the theory by proposing a mechanism, speculating that the G-protein-coupled receptors discovered by Linda Buck and Richard Axel were actually measuring molecular vibrations using inelastic electron tunneling, rather than responding to molecular keys that work by shape alone.[2]"
    Again, there is no such thing as a "shape" theory of odor perception. This Wikipedia page has a good discussion of the accepted olfaction receptor theory of Axel & Buck:
    http://en.wikipedia.org/wiki/Olfactory_receptor
    All these moments will be lost in time, like tears in rain.

  9. #9

    Default Re: New study contradicts Luca Turin's theory?

    Take a look at:

    http://www.ted.com/index.php/talks/l..._of_scent.html

    The "fact" I was referring to can be found from 5:23 to 5:40. If that is accurate, shape theory can't account for it, and must not be accepted until a solid explanation can be given. On the other hand, I haven't heard of anything undeniable that refutes Turin's theory. If anyone would like to speak to this in a way us non-scientists can understand, I think many BNers would appreciate it (including me, of course). But one thing I know is that if there is an undeniable fact that contradicts a theory, that theory can't be accepted until there is a way to explain the fact (and that explanation can't violate the laws of nature or logic).
    Last edited by Bigsly; 27th December 2008 at 04:12 AM.

  10. #10

    Join Date
    Mar 2008
    Location
    brooklyn NYC
    Posts
    1,979
    Post Thanks / Like
    Blog Entries
    1

    Default Re: New study contradicts Luca Turin's theory?

    well, being a scientist, i can say with pure confidence that NO THEORY is really actually ever 100% refuted, being as there are rarely aspects of molecular biology that are ever evidenced as "Fact"

    these are simply theories. Personally I find this new theory a little comical, with its references to G-protein receptors.......most of the body runs on relation to G-protein receptors, so it's not exactly a revelation that olfactory sensation is linked to it as well. There's nothing really too new in the article, as far i can see......just added details to a larger theory, in all likelihood.

    Neuroscience is so complicated....the whole field changes every 10 years or so....so don't be surprised if you see plenty of these theories pop up frequently throughout your lives

    oh....and you'll never seen one that explains things to you....correctly----because it will get overturned shortly anyways!
    Last edited by everso; 27th December 2008 at 04:27 AM.

  11. #11

    Default Re: New study contradicts Luca Turin's theory?

    That is my sense too, everso, but I don't have the credentials to make such a statement. For me, the "bottom line" is obvious, however, and that is if two molecules have the same shape but smell clearly distinct, the smell theory is gone, regardless of whether LT's theory needs further elucidation or not. One can't say that because one theory has problems the other must be right, which is what some of the smell theory people seem to imply (from what I've read). That's where basic logic comes into play. Worry about your own theory being shot full of holes by simple experiments before worrying about what LT says !

  12. #12
    Moderator

    Redneck Perfumisto's Avatar
    Join Date
    Feb 2008
    Location
    Spiritually, Kansas
    Posts
    13,084
    Post Thanks / Like
    Blog Entries
    37

    Default Re: New study contradicts Luca Turin's theory?

    I'll chime in with more detail later, but I agree with everso - theories and their life and death are never as simple as they appear in the daily media, and are even more complicated than what you get on Nova and the like, although I will admit that those folks do an excellent job of balancing what they leave in and leave out.

    Bigsly, I agree that there are many things (including all of these things that Turin cites) which are problematic for extremely simplistic shape theories. On the other hand, the standard key/lock model has worked nicely for so many things. And as everso points out, saying that G-protein-coupled receptors are involved with anything biochemical is like saying tires are involved with cars. Yeah. No surprise.

    We have some facts that are in search of a (likely) complex group of theories which explains everything, such as the many theories needed to answer "why does the car move?" My current view is that Turin has in his hands some facts and a viewpoint which have to be answered, and that the current state of knowledge is inadequate until they are addressed. Noting that modern car keys operate by both shape and electronic signature, it is entirely conceivable that the black box connecting molecules to nerve signals is multideterminate, involving multiple interactions of various types along the way which affect the final outcome. To that degree, I think it is highly likely that Turin is right in that shape alone is wrong.

    Bear in mind that Einstein actually opposed the idea of black holes and wrote a paper disproving them. In a sense, his theory was right, but his own interpretation of it (at that time) was not. Newton falls apart under certain conditions, Einstein under others. Both "theories" are right - and so is whatever comes next. And both are wrong. Thus what everso says is so true - the whole idea of theories as firm objects that don't change with time? Not the way it really is.
    * * * *

  13. #13

    Default Re: New study contradicts Luca Turin's theory?

    I think that is what often happens, that is, an idea works in practice for 90% of applications, but the other 10% is apparently wrong. The problem comes in when those who believe the 90% somehow covers 100%, and they criticize the guy who may be able to explain the 100%, if given the opportunity (which today means big research dollars).

  14. #14

    Default Re: New study contradicts Luca Turin's theory?

    I agree that there are many things (including all of these things that Turin cites) which are problematic for extremely simplistic shape theories.
    The currently accepted theory, for which Axel and Buck received the Nobel prize, is not a shape theory. "Shape theory" exists only as a straw man.

    http://en.wikipedia.org/wiki/Straw_man
    All these moments will be lost in time, like tears in rain.

  15. #15

    Default Re: New study contradicts Luca Turin's theory?

    Please, then, state the shape theory explicitly for us.

  16. #16

    Default Re: New study contradicts Luca Turin's theory?

    Please, then, state the shape theory explicitly for us.
    Again and again, there is no accepted "shape theory", it could be whatever you feel you need to set up a suitable straw man.

    http://en.wikipedia.org/wiki/Straw_man
    All these moments will be lost in time, like tears in rain.

  17. #17

    Default Re: New study contradicts Luca Turin's theory?

    I don't know how you learned science, but what I learned is that the scientist needs to put a hypothesis forward, then experiments are done which confirm or refute it. It can never be a "fact" because it's always possible that something wasn't controlled for that has a causative role, but you cannot have undeniable experimental data that is inconsistent with it. If "shape theorists" want to be taken seriously, they need to step up and tell us what their hypothesis is. Perhaps they have done this, but I haven't seen it, which is why I asked for it to be stated explicitly. If they can't do that much, all they'll get from me is a bit of laughter.
    Last edited by Bigsly; 27th December 2008 at 11:15 PM.

  18. #18

    Default Re: New study contradicts Luca Turin's theory?

    The currently accepted theory of odor perception, for which Axel and Buck received a Nobel prize, is _not_ a "shape theory".

    http://en.wikipedia.org/wiki/Straw_man
    All these moments will be lost in time, like tears in rain.

  19. #19

    Default Re: New study contradicts Luca Turin's theory?

    One thing these two must do is to provide a logical explanation for two molecules of the same shape not smelling very similar (and it can't violate the known "laws of nature," obviously). If someone can supply a link to this explanation, we can move forward. If they have no explanation, I don't see how any reasonable person can take them seriously, regardless of what award they won (President Bush has given out some awards, for example).
    Last edited by Bigsly; 27th December 2008 at 11:37 PM.

  20. #20

    Smile Re: New study contradicts Luca Turin's theory?

    Quote Originally Posted by Bigsly View Post
    That's what it sounds like to me, but it's a bit technical. Thoughts? Here it is:

    Shakespeare wrote “a rose by any other name would smell as sweet.” But would it if the molecules that generate its fragrance were to change their shape?

    That’s what Dr. Kevin Ryan, Assistant Professor of Chemistry at The City College of New York (CCNY) and collaborators in the laboratory of Dr. Stuart Firestein, Professor of Biology at Columbia University, set out to investigate. Their findings, reported December 22 in the journal “Chemistry & Biology,” shed new insight into how our sense of smell works and have potential applications in the design of flavors and fragrances.

    When odor-producing molecules, known as odorants, pass through the nose, they trigger intracellular changes in a subset of the approximately 400 different varieties olfactory sensory neurons (OSN) housed in the nose’s internal membrane tissue, Professor Ryan explained. The unique reaction pattern produced, known as the olfactory code, is sent as a signal to the brain, which leads to perception of odors.

    Professor Ryan and his team wanted to learn how these receptor cells respond when odorants change their shape. They studied the odorant octanal, an eight-carbon aldehyde that occurs in many flowers and citrus fruits. Octanal is a structurally flexible molecule that can adapt to many different shapes by rotating its chemical bonds.

    The researchers designed and synthesized eight-carbon aldehydes that resembled octanal, but had their carbon chains locked by adding one additional bond. These molecules were tested on genetically engineered OSNs known to respond to octanal. This work was done in Professor Firestein’s laboratory at Columbia.

    The aldehyde molecules that could stretch to their greatest length triggered strong activity in the OSNs. However, those molecules whose carbon chains were constrained into a U shape blocked the receptor and left the cell unable to sense octanal.

    “Conformationally constrained odorants were more selective in the number of OSNs they activated,” Professor Ryan noted. “The results indicate that these odorant molecules might be able to alter fragrance mixture odors in two ways: by muting the activity of flexible odorants present in a mixture and by activating a smaller subset of OSNs than chemically related flexible odorants. This would produce a different olfactory code signature.”

    Olfactory receptors belong to the G-protein coupled receptor (GPCR) class of proteins, a family of molecules found in cell membranes throughout the body. Professor Ryan pointed out that half of all commercial pharmaceuticals work by interaction with proteins within this family. Thus, the findings could also have applications to GPCR drug design, as well.

    This can be found at: http://www.sciencedaily.com/releases...1222163053.htm
    Thanks for the link. In a former life I was a biochemist...this is really interesting stuff!

  21. #21

    Default Re: New study contradicts Luca Turin's theory?

    One thing these two must do is to provide a logical explanation for two molecules of the same shape not smelling very similar
    Because they have different binding strengths to the various odor receptors.

    http://en.wikipedia.org/wiki/Olfactory_receptor
    http://en.wikipedia.org/wiki/Ligand_(biochemistry)
    All these moments will be lost in time, like tears in rain.

  22. #22

    Default Re: New study contradicts Luca Turin's theory?

    Okay, so the next logical step would be to get a bunch of molecule pairs that are the same shape but smell clearly different and determine the binding strengths, to determine if this ideas is consistent with reality. Has this been done? If so, can anyone provide citations to the actual scientific literature (that is available free online)?

  23. #23

    Default Re: New study contradicts Luca Turin's theory?

    Okay, so the next logical step would be to get a bunch of molecule pairs that are the same shape but smell clearly different and determine the binding strengths, to determine if this ideas is consistent with reality.
    First you would have to define what you mean by same shape. Do propanol, propanal, propanethiol and propylamine have the same shape? But this is not necessary, it has been demonstrated that chemicals that smell similar activate the same spectrum of receptors and chemicals that smell differently activate a different spectrum of recptors.

    Has this been done? If so, can anyone provide citations to the actual scientific literature (that is available free online)?
    Very little scientific literature is available for free on the internet but you could for example read pages 7-10 of Linda Buck's Nobel Prize acceptance speech.
    http://nobelprize.org/nobel_prizes/m...ck-lecture.pdf

    or Google:
    http://www.google.com/search?hl=en&q...ption&aq=f&oq=
    Last edited by dcampen; 28th December 2008 at 02:03 AM.
    All these moments will be lost in time, like tears in rain.

  24. #24

    Default Re: New study contradicts Luca Turin's theory?

    Well, one thing that's clear is that you are unaware about just how much scientific literature is available for free. Have you heard of pubmed.com?

    I should disclose why this area of "science" concerns me. A friend told me about a book, "The Billion Dollar Molecule." I read it, and found such passages as:

    “…not all the equations we use to describe those interactions are accurate. Some of them are fudge factors. Some of them are thought to be correct even though the experimental data they’re based on are wrong, only nobody knows that because nobody’s gone back and double-checked the experiments. Some are pure guesses. There are assumptions, biases. There’s user error. There’s imprecision in the hardware and software.”

    And: “I mean, what are the basic concepts of biology and how sure are we of them? Well, there aren’t any, hardly. It isn’t that the people are stupid, it’s that the data isn’t there.”

    These are statements made by "top scientists." And I've read other books which confirm this problem. I am not interested in reading acceptance speeches. If someone wants to claim that his or her theory is to be regarded almost like a religious doctrine, then that theory better be "air tight." There had better not be any undeniable evidence to the contrary, because if there is, that person loses all credibility with me. I have the feeling that in this olfactory field, many are just fiddling around with "models," making all kinds of assumptions, trying to force square pegs into round holes, and viciously attacking (or perhaps worse, totally ignoring) anyone who has evidence to the contrary. The way to dispel this well-deserved concern is to take on all evidence that appears to support LT's theory and explain, in detail yet comprehensible to those of sound mind, why exactly LT can't be right and why the theory they support is so strong. So far, I haven't seen that done. That is the way I was taught to do scholarship.
    Last edited by Bigsly; 28th December 2008 at 03:13 AM.

  25. #25

    Default Re: New study contradicts Luca Turin's theory?

    Well, one thing that's clear is that you are unaware about just how much scientific literature is available for free. Have you heard of pubmed.com? Come on !
    OK, since you are going to start being nasty then I am finished with this discussion.
    All these moments will be lost in time, like tears in rain.

  26. #26

    Default Re: New study contradicts Luca Turin's theory?

    I just can't believe that someone who obviously knows as much as you do about biology doesn't know about pubmed or do you not consider that substantial? I apologize if I offended.

  27. #27
    Moderator

    Redneck Perfumisto's Avatar
    Join Date
    Feb 2008
    Location
    Spiritually, Kansas
    Posts
    13,084
    Post Thanks / Like
    Blog Entries
    37

    Default Re: New study contradicts Luca Turin's theory?

    Quote Originally Posted by dcampen View Post
    Not that I remember.

    The one thing the Burr book was good at was manufacturing artificial controversy in order to sell copies of the book. The scientific exposition was terrible. I thought the most egregious "error" was repeatedly and continually confounding the mythical "shape" theory of odor perception with the currently accepted odorant receptor theory of Axel and Buck in order to set up a straw man.
    Do you think that was merely oversimplification, or the journalistic/editorial propensity to generate marketable controversy (or both)?

    Bigsly - this is what he means by straw man. I'll try to explain a bit. This is also what everso was addressing, and me too - all from different angles. And pay close attention to what TGL said above, because that's my understanding, too.

    The current theory has "moved on" if you will, and the modern receptor theory (thanks for the link, David) has pretty much filled in most of the gaps in the understanding of olfaction - at least from what I can get my hands on. Even if it's possible to label older, cruder receptor-based theory as the boogey-man of "shape theory", rather than saying it's completely mythical, then it's simply not fair to do battle against it. However, Turin is not, really. You can look at this document on his web site to see where he is currently going. As I suspected, he's moving more or less around Axel and Buck and positioning his ideas in the still-black-boxy area of receptor activation, while admitting the unarguable aspects of the current receptor theory.

    Like everso and I are trying to tell you, science is very dynamic.

    The current receptor theory - vis-a-vis the numbers and types of receptors and their wiring at the nose end - is very strong. There was some peripheral research associated with it which was recently invalidated (I think due to scientific misconduct), but it was tangential, and does not in any way affect the big picture, or the question at hand. This isn't like edgy physical and cosmological theory - a ton of speculation and working hypothesis with very little prediction. There is so much good experimentation here, there is no question in my mind whatsoever that the basics of olfaction have been nailed down. In my opinion, Turin's ideas have to operate in the smaller region of currently unknown problem space. I'll get to that later. But let me explain and strengthen what David is saying about the existing theory.

    The existing theory identifies a large number of receptors with (apparently) a high degree of variability in terms of odorant molecules that they discern. Each sensory cell expresses a single type of receptor, and cells of the same type converge their signals together before the signal heads to the brain. This scenario is highly compelling - it is simple, biologically efficient, readily explained by evolution, and (in my opinion) potentially explains everything. The reason for the latter is that it is fundamentally combinatorial. The large number of different receptors provides a very finely-sampled spectrum of responses for every conceivable molecule. It's like vision with a thousand different types of cones at different frequencies. Imagine color vision with 1000 or 2000 colors. The amount of fine-grained differentiation that is possible is likely to be tremendous. Thus, the current state of knowledge alone may be enough to explain everything (just hang on - I'll address those molecules next). However, Turin takes issue with the idea that receptors relying only on shape could account for the facts. He is basically postulating a mechanism by which receptors could involve both shape and electronic interactions. I think everybody agrees with that, but the exact mechanism of the electronic interactions is what he's postulating - and it's something different from what most people have thought.

    Receptor interactions are highly complex. Add to that the fact that we are talking about hundreds or thousands of receptor types. Even if you could have two molecules with truly identical shapes, but different electronics, then one must realize that receptor binding would likely still be differentiable, based on those electronics, when sampled across such a huge number of receptors, or even a small subset. I'm not saying that they have to be differentiable, but it's possible - without resorting to anything elaborate. Because of Occam's Razor - the idea that we shouldn't be fancy if we don't have to be - that's not good for what remains of Luca's core idea - that odorant molecules do the final triggering of the receptor by a quantum mechanical coupling. What if we just make the multitude of receptors sensitive enough based on existing stuff?

    Now if you read that PDF, you'll see that Turin addresses the whole issue of combinatoriality, and actually challenges an experiment that dealt with it by his own analysis of the data. I didn't follow it through myself - I haven't the time nor the will to scrutinize it, so I take his analysis on a bit of faith. But he basically believes that data showing differential odorant profiles at different receptors can be interpreted as being proportional to the hydrophobicity (water-repellancy) of the molecules, leaving his model of the mechanism of ultimate detection still viable. Bottom line - he is making his model fit in with the current model of Axel and Buck.

    I prefer to be open-minded about this. Some of the things that Turin points out are the kind of facts that (I believe) are irritating, and should bother good scientists, who are not content until all the annoying facts are explained. The borane/thiol thing - that bothers me (and I think it should bother good scientists, too.) These molecules are vastly different from an electronic standpoint - far more different than alcohols are from thiols. Yet Turin makes the admittedly cockeyed hypothesis that these things should smell the same based on their quantum energetics in the IR range, and - lo and behold - they do. I'll be honest - I would have a really hard time throwing out that fact. Add in some other stuff in the PDF I cite above, and I'm willing to suspend my opinion for or against his work until there is more evidence. Now I do take issue with some of his work. For instance, he cites triethylamine-borane as being an example of a borane with a shifted vibration, accounting for its loss of the typical borane odor. Well, the fact is also that it's simply a complex between a borane and an amine, and while it's "just" a complex (meaning weakly bound), it's still strong enough of a bond that (in my opinion) there is likely to be a significant difference in receptor interactions merely because of the quenching of the borane's chemistry by the amine. Bottom line - bad example. Still, there are other examples that he has which are slightly more compelling. Taken as a whole, I think there's still room for his theory. And even if he's wrong about the ultimate mechanism, he has assembled an array of questions which need some explanation.

    Now, finally, an explanation of this paper you mention. You can actually look at the structures of the "locked" molecules here. I don't see a lot of contradiction of his theories, because this pinning of the molecules has basically altered their shapes fundamentally. We know that if you make changes to the shapes of aldehydes, they will smell different, although to a trained nose they still all smell like aldehydes. The deeper scientific purpose of the research is hidden in the link you gave, but in the PDF I just cited, it is hinted at. It looks like they were hoping to spot the actual conformation of the octanal ligand in the receptor, based on which one of their locked octanals exhibited increased binding relative to normal octanal. The results, interpreted that way, would argue for a more or less linear conformation, since their cyclopropane analog is the one that did just that. That seems to be echoed in the less detailed article.

    Overall, I see some cases where I think Turin's work would benefit from collaboration with other labs, particularly in double-blinding and quantifying his examples. However, I'm not entirely convinced that non-noses are qualified to carry some of this stuff out. And while I am still skeptical of some of Turin's results, I am also skeptical of some of the labs whose findings have disagreed with his.

    Sorry if this is all a blur, but I got carried away. I hope it's halfway understandable.

    Time for bed. I'll respond as soon as I can tomorrow. Ciao, and g'nite!
    * * * *

  28. #28

    narcus's Avatar
    Join Date
    Mar 2005
    Location
    Königl. Preussen
    Posts
    4,579
    Post Thanks / Like

    Default Re: New study contradicts Luca Turin's theory?

    Quote Originally Posted by Redneck Perfumisto View Post
    ...Sorry if this is all a blur, but I got carried away. I hope it's halfway understandable.
    Not a blur, and thank you RP! For the first time I get closer to understanding some of the controversy.
    Last edited by narcus; 28th December 2008 at 09:57 AM.
    'Il mondo dei profumi è un universo senza limiti: una fraganza puo rievocare sensazioni, luoghi, persone o ancora condurre in uno spazio di nuove dimensioni emozionali' L. V.

  29. #29

    Join Date
    Mar 2008
    Location
    brooklyn NYC
    Posts
    1,979
    Post Thanks / Like
    Blog Entries
    1

    Default Re: New study contradicts Luca Turin's theory?

    Quote Originally Posted by dcampen View Post
    OK, since you are going to start being nasty then I am finished with this discussion.
    he simply asked if you'd heard of Pubmed. a valid question. No need to sit and cry about it.

    Redneck and bigsly, you guys are full of nice insights into this subject...thank you for providing all of this! some very nice reading i must say! cheers. time for me to sit down and read some of the details.....better get me some nice strong coffee!
    Last edited by everso; 28th December 2008 at 01:05 PM.

  30. #30

    Default Re: New study contradicts Luca Turin's theory?

    I am impressed with everyone who is contributing to this thread! I'll just keep lurking and maybe it will all sink in!

  31. #31

    Default Re: New study contradicts Luca Turin's theory?

    The thing that I find very troubling is that I was taught in grad school that you had better make an "airtight" case or else you would have to expect fellow scholars to "rip you to shreds" (and this wasn't even a scientific discipline!), yet scientists (and those in biology seem to be the worst offenders) don't seem to have any qualms about dismissing the ideas of others out of hand when there is so much evidence against their own. If Redneck P. is right, there is no reason for any one theory to be viewed as anything more than an educated guess at this point, given that there is evidence against their idea as well as a compelling competing notion. If you want to make a case, then make it as strong as possible, It's possible that two theories can both explain 99% of the evidence, but only the right one can explain 100%, and this is something too many scientists these days don't seem to understand.

    UPDATE: If you got to pubmed.com and search for sense of smell, you find interesting stuff like:

    "No two roses smell exactly alike, but our brain accurately bundles these variations into a single percept 'rose'. We found that ensembles of rat olfactory bulb neurons decorrelate complex mixtures that vary by as little as a single missing component, whereas olfactory (piriform) cortical neural ensembles perform pattern completion in response to an absent component, essentially filling in the missing information and allowing perceptual stability. This piriform cortical ensemble activity predicts olfactory perception."

    Nat Neurosci. 2008 Dec;11(12):1378-80. Epub 2008 Nov 2.

    http://www.ncbi.nlm.nih.gov/pubmed/1...ubmed_RVDocSum
    Last edited by Bigsly; 29th December 2008 at 12:20 AM.

  32. #32
    Moderator

    Redneck Perfumisto's Avatar
    Join Date
    Feb 2008
    Location
    Spiritually, Kansas
    Posts
    13,084
    Post Thanks / Like
    Blog Entries
    37

    Default Re: New study contradicts Luca Turin's theory?

    Quote Originally Posted by Bigsly View Post
    The thing that I find very troubling is that I was taught in grad school that you had better make an "airtight" case or else you would have to expect fellow scholars to "rip you to shreds" (and this wasn't even a scientific discipline!), yet scientists (and those in biology seem to be the worst offenders) don't seem to have any qualms about dismissing the ideas of others out of hand when there is so much evidence against their own. If Redneck P. is right, there is no reason for any one theory to be viewed as anything more than an educated guess at this point, given that there is evidence against their idea as well as a compelling competing notion. If you want to make a case, then make it as strong as possible, It's possible that two theories can both explain 99% of the evidence, but only the right one can explain 100%, and this is something too many scientists these days don't seem to understand.
    I think it's a lot like a discussion board, though heavily, heavily moderated. Some people do "safe" work where they dot all the i's and cross all the t's, and never face criticism. But they may also end up a day late and a theory short. Others jump in right away with ideas that are likely but still early, and brave the inevitable opposition.

    It's important to realize, from the history of science, that the public view of theories (and by public I mean the scientific community and the media who follow behind them) is often wrong, but science has a terrible record of doing mea culpa, in my opinion. Science is very good at saying "we are now right", but it doesn't like to focus on its past errors. I was blessed to have some professors who imparted to me the wonderful history of wrongness in chemistry. I'm also old enough to remember when ideas such as terrestrial impacts were mocked as religious garbage, and general relativity was still considered iffy. In my own field, the errors were less dramatic, but just as colorful. A famous chemist once mocked the idea of tetrahedral carbon bonding and its role in chirality as a hooker being brought into good society (it didn't help that the scientist advancing the idea wasn't from a "good" school). In another case, an essential answer in quantum chemistry went unnoticed for years, and an empirical result in Germany was doubted because the work was too elegant to be believed, and the result unexpected (in his case, it didn't help that he was a Jew and things were getting nasty in Germany). Science has flaws because science is done by people. If there is one thing I would impart to young scientists, that would be it.

    Bigsly, I would say that no theory is ever on 100% solid ground. They all seem to have a boundary at which they don't operate at 100%. Everything breaks down at some point, and either gets help from other theory, or is a big fat question mark and requires upgrading or extension. But you are right - the few nasty players who diss the opposing views without respect or self-examination take the fun out of the game. I will always respect my former advisor for the fact that he would treat with honor even the least respected and most controversial scientists of his field - particularly those who opposed his own views. As it should be. Science is no longer a rich gentleman's pastime, but we can still be ladies and gentlemen.

    It's all rather interesting, but I personally prefer being a bystander now!
    * * * *

  33. #33
    zztopp's Avatar
    Join Date
    Apr 2006
    Location
    the Dirty South
    Posts
    6,632
    Post Thanks / Like

    Default Re: New study contradicts Luca Turin's theory?

    I dont have a chemistry background but I published many papers (3 journals, 5 conference and a number of workshop papers) in computer science publications during my recent grad school tenure - our group was working on a recently rejuvenated subfield of CS (two level grammar, and grammar inference) so I just have a bunch of general questions:

    1) I believe Turin is currently at MIT. Is he still continuing work on his theory and drumming up support for it?

    2) What other academic/industry research groups are doing research on the same theory as Turins'?

    3) Does anyone know of any recent papers by Turin (recent as in within the past 3 years) ?

    These questions are key because it can be very hard to get a novel idea published in journals with a decent ISI/impact factor - initially the reaction of the reviewers is almost always "No way! this cannot be! It is utter nonsense and no one will care for it !"
    -

  34. #34

    Default Re: New study contradicts Luca Turin's theory?

    Well, I know that Einstein's relativity has been tested over and over again, which is appropriate. But, as those quotations from "The Billion Dollar Molecule" make clear, many if not most biologists seem to think that their models are established "facts," and they dismiss out of hand anyone who dares criticize those models. A theory is never 100%, which is why it's called a theory and not a fact. The thing that is so disturbing here is that it appears that this should be a rather simple problem to solve, experimentally. You get molecules that everyone can agree are the same shape or clearly not the same shape, and you see if either idea works all the time. If some are now talking about binding strength, I'd like to know about the primary data on this. Can it be measured easily? If so, again, why not do the experiments and determine who is correct? Or can they not even agree on molecules being the same shape or clearly different?
    Last edited by Bigsly; 29th December 2008 at 05:45 AM.

  35. #35
    Moderator

    Redneck Perfumisto's Avatar
    Join Date
    Feb 2008
    Location
    Spiritually, Kansas
    Posts
    13,084
    Post Thanks / Like
    Blog Entries
    37

    Default Re: New study contradicts Luca Turin's theory?

    Quote Originally Posted by zztopp View Post
    I dont have a chemistry background but I published many papers (3 journals, 5 conference and a number of workshop papers) in computer science publications during my recent grad school tenure - our group was working on a recently rejuvenated subfield of CS (two level grammar, and grammar inference) so I just have a bunch of general questions:

    1) I believe Turin is currently at MIT. Is he still continuing work on his theory and drumming up support for it?

    2) What other academic/industry research groups are doing research on the same theory as Turins'?

    3) Does anyone know of any recent papers by Turin (recent as in within the past 3 years) ?

    These questions are key because it can be very hard to get a novel idea published in journals with a decent ISI/impact factor - initially the reaction of the reviewers is almost always "No way! this cannot be! It is utter nonsense and no one will care for it !"
    Great questions, zz! I've picked up partial answers to some of these - I'll look more closely now. But until then, let me give you what I know...

    (1) I heard he was going there. If so, that's what I'm presuming, but haven't verified. Narcus?

    (2) I have not seen any people who seem to be advancing his viewpoint, although I saw a theoretical paper (I think in England) saying it was plausible, and one team at Rochester who tried to do something he predicted and got negative results. I'll get the references if I can find them again.

    (3) I've seen several patents of his coming through, but they seem to be for substances that spin off his research, not the examples from the research itself. For instance, several of them are for sulfur-containing analogs of known fragrance substances. He appears to have examined various substances that make sense in the course of his research, and gets auxilliary ideas about them that go into patents of a tangentially related nature in terms of utility. The guy seems to be brimming with ideas.

    I presumed that if he got a spot at MIT, it was because his research is "hot" even if controversial. His commercial ties are likely a bonus. I would say that it would be justified. Too many people do dull, safe stuff. People who go after tough questions may attain gadfly status, but from a scientific viewpoint, they stir up the pot, and from an administrative viewpoint, they attract attention.

    Kudos to you for academic IT work - sounds like fascinating stuff you did. More proof that you appreciate complexity and precision!
    * * * *

  36. #36
    Moderator

    Redneck Perfumisto's Avatar
    Join Date
    Feb 2008
    Location
    Spiritually, Kansas
    Posts
    13,084
    Post Thanks / Like
    Blog Entries
    37

    Default Re: New study contradicts Luca Turin's theory?

    Quote Originally Posted by Bigsly View Post
    The thing that is so disturbing here is that it appears that this should be a rather simple problem to solve, experimentally. You get molecules that everyone can agree are the same shape or clearly not the same shape, and you see if either idea works all the time.
    It's not simple, Bigsly, my friend. That's what David is trying to explain. Molecules are not just shapes - they're fuzzy little electrical necklaces that flop around every which way. Even if we find two molecules with exactly the same shape, but different electronics (like rigid metallocenes with different metal atoms buried in the center), there could be lots of valid, non-Turin reasons for a difference to show up. Sometimes in science we luck out and get a single experiment that shakes up everything and provides a knife-edge to test theory, but usually we don't, and even if we do, we often don't recognize it. In this case, the same shape but different electronics might give no difference. That looks easy (a no for Turin), but the result is still subject to interpretation - there could be a reason why there was no difference (though you are SO correct about using molecules PLURAL). But if there is a slight difference (more likely), there's a fight as to why it happened. Non-Turin theories invoking other electrostatic or chemical phenomena could explain it. If there's a huge difference, it looks good for Turin, but again - subject to interpretation, or competing theories. A different type of electronic theory could explain it. And Occam's Razor hovers overhead the whole time, ready to break a tie or snuff a Rube Goldberg theory.

    Quote Originally Posted by Bigsly View Post
    If some are now talking about binding strength, I'd like to know about the primary data on this. Can it be measured easily? If so, again, why not do the experiments and determine who is correct? Or can they not even agree on molecules being the same shape or clearly different?
    The experiments are coming - clearly, people are probing olfactory receptors in a big way now. I think the verdict will be coming in soon. But it's important to remember that we test the receptors with real molecules - not hypothetically identical/different ones. For example, the molecules being tested in the study you cite are not identical to the conformations of straight-chain octanal that they are trying to mimic. They have two hydrogen atoms removed to close the ring and hold it still. Thus they are an approximation. Still, we can learn from them. We can now hook up these receptors like wires and test them, so the answer to your question is yes, it's easily measured now (not sure if it's "easy", but it's very doable). I think the answer to the last question is that we can agree on molecules, but there are none that are "perfect" test substances. So the answer is to do enough different cases to look for a preponderance of evidence.

    Science is done with a finite number of selections from a finite number of possible approximations that we can to some degree test. If that sounds like it opens up the possibility of interpretation, then yes, it does. But only to a point. As more and more evidence arrives, things sharpen up, and the rock-solidness of the winning theories appears. That's why evolution is a no-brainer for scientists. Billions (literally) of dovetailing biological facts are only interpretable in terms of it. It's like atoms. If you don't like 'em, tough. THAT is when theories are solid like you would like them to be. But trust me - there are always surprises. The fact that we discovered a bounded form of graphite (fullerenes) only recently shows that we don't know everything even when we think we do.

    Competing theories are sometimes like two kids splashing water out of a puddle. Both sides win until there are no more facts to explain, and then you see that both were right in a sense - they were really just viewpoints and approximations of the same truth. That's become more common, it seems, and now scientists have theories of theories and theories about types of theories. Yeah, it's a mess. But I think it's still beautiful.
    * * * *

  37. #37

    Default Re: New study contradicts Luca Turin's theory?

    (1) I heard he was going there. If so, that's what I'm presuming, but haven't verified.
    The MIT directory lists him as a "Visiting Scientist".
    http://web.mit.edu/bin/cgicso?query=Turin
    All these moments will be lost in time, like tears in rain.

  38. #38
    zztopp's Avatar
    Join Date
    Apr 2006
    Location
    the Dirty South
    Posts
    6,632
    Post Thanks / Like

    Default Re: New study contradicts Luca Turin's theory?

    Quote Originally Posted by Redneck Perfumisto View Post
    Great questions, zz! I've picked up partial answers to some of these - I'll look more closely now. But until then, let me give you what I know...

    (1) I heard he was going there. If so, that's what I'm presuming, but haven't verified. Narcus?

    (2) I have not seen any people who seem to be advancing his viewpoint, although I saw a theoretical paper (I think in England) saying it was plausible, and one team at Rochester who tried to do something he predicted and got negative results. I'll get the references if I can find them again.

    (3) I've seen several patents of his coming through, but they seem to be for substances that spin off his research, not the examples from the research itself. For instance, several of them are for sulfur-containing analogs of known fragrance substances. He appears to have examined various substances that make sense in the course of his research, and gets auxilliary ideas about them that go into patents of a tangentially related nature in terms of utility. The guy seems to be brimming with ideas.

    I presumed that if he got a spot at MIT, it was because his research is "hot" even if controversial. His commercial ties are likely a bonus. I would say that it would be justified. Too many people do dull, safe stuff. People who go after tough questions may attain gadfly status, but from a scientific viewpoint, they stir up the pot, and from an administrative viewpoint, they attract attention.

    Kudos to you for academic IT work - sounds like fascinating stuff you did. More proof that you appreciate complexity and precision!
    Thanks for your answers R_P. I quite enjoyed reading your detailed writings here. Looks like you are up-to-date in your area of interest. Maybe Turin should hold an audience with you.
    -

  39. #39
    Moderator

    Redneck Perfumisto's Avatar
    Join Date
    Feb 2008
    Location
    Spiritually, Kansas
    Posts
    13,084
    Post Thanks / Like
    Blog Entries
    37

    Default Re: New study contradicts Luca Turin's theory?

    Quote Originally Posted by dcampen View Post
    The MIT directory lists him as a "Visiting Scientist".
    http://web.mit.edu/bin/cgicso?query=Turin
    Thanks very much, David. That led me to several links at MIT which I'm analyzing now. Here is one, to somebody who is collaborating with him...

    http://web.media.mit.edu/~manup/Manu...b/Welcome.html
    * * * *

  40. #40
    Moderator

    Redneck Perfumisto's Avatar
    Join Date
    Feb 2008
    Location
    Spiritually, Kansas
    Posts
    13,084
    Post Thanks / Like
    Blog Entries
    37

    Default Re: New study contradicts Luca Turin's theory?

    Quote Originally Posted by zztopp View Post
    Thanks for your answers R_P. I quite enjoyed reading your detailed writings here. Looks like you are up-to-date in your area of interest. Maybe Turin should hold an audience with you.
    Thanks, zz. Honestly, I feel humbled to be posting in a place that Turin found worthwhile. But it's clear why he did. Few places would tolerate this level of discussion of arts and sciences with such a high degree of community interest, as opposed to snickers and yawns.

    I would love to follow Turin's work as closely as I once did other subjects, but my employer's resources can no longer be used for anything but the tasks needed to get the job done. Not an unreasonable request in these hard times, when customers have to make even harder choices. Better that my pleasure reading walk the plank, than somebody else's job.
    Last edited by Redneck Perfumisto; 30th December 2008 at 03:16 AM. Reason: (my ){2}
    * * * *

  41. #41

    Default Re: New study contradicts Luca Turin's theory?

    Quote Originally Posted by kbe View Post
    I am going to spend a night in a Holiday Inn Express and then re-read that article.
    hahahah good one! And if you still don't get it, maybe you should switch your car insurance to Gieco, that way you can at least save a lot of money on your car insurance!

  42. #42
    dpak's Avatar
    Join Date
    Dec 2007
    Location
    Next to the bottle of Van Winkle Special Reserve
    Posts
    664
    Post Thanks / Like

    Default Re: New study contradicts Luca Turin's theory?

    Quote Originally Posted by Maz24 View Post
    hahahah good one! And if you still don't get it, maybe you should switch your car insurance to Gieco, that way you can at least save a lot of money on your car insurance!
    I smell a shill!
    Now if I only understood how my nose-hole can detect the shillyness.
    Marge: Do you want your son to become Chief Justice of the Supreme Court or a sleazy male stripper?
    Homer: Can't he be both, like the late Earl Warren?



  43. #43

    Default Re: New study contradicts Luca Turin's theory?

    What about utility and predictability? It appeared that one of the drivers for Turin's work was his assessment that dominant theories of the early 90's had little or no predictive utility for the perfume industry. Have the recent developments in theory resulted in advancements the ability to predict how new molecules or will smell?

  44. #44
    Moderator

    Redneck Perfumisto's Avatar
    Join Date
    Feb 2008
    Location
    Spiritually, Kansas
    Posts
    13,084
    Post Thanks / Like
    Blog Entries
    37

    Default Re: New study contradicts Luca Turin's theory?

    Quote Originally Posted by Hanuman View Post
    What about utility and predictability? It appeared that one of the drivers for Turin's work was his assessment that dominant theories of the early 90's had little or no predictive utility for the perfume industry. Have the recent developments in theory resulted in advancements the ability to predict how new molecules or will smell?
    I'm trying to get a sense of this (no pun intended) using my weak home resources. For a gloomy view, look here, at one of my favorite chem blogs. To quote:

    The take-home lesson is that there are no major SAR trends in odor that you can count on. A substitution that works in one series can do nothing when applied to a closely related compound, or it can take the odor off in a completely unexpected direction.
    I haven't seen the cited article, so I'm unable to comment if that's a fair restatement of the conclusions. It was 2006, so it's pretty recent. In any case, I think that viewpoint is mostly from a practical standpoint. If you have to pretty much map out every small local region in chemspace to find correlations, and they don't translate across chemspace with any reliability, then you don't really have anything better than empiricism, in my opinion.

    Now, personally, I'm a believer in Hilbert's epitaph - Wir müssen wissen. Wir werden wissen. (We must know. We shall know.) Even knowing what can't be known - the limits of knowing - is good knowledge. But I'm hopeful that the modern understanding of olfactory receptors will, in fact, lead somewhere.

    So..... Continuing to look around, I am finding a ton of good science showing (what looks to me like) slow and steady progress. I even found a recent article (abstract here) that I was willing to fork over the cash to read. The abstract starts off with a rehash of the combinatorial viewpoint, including the idea that odorants could be both agonists and antagonists (makes sense). The highlight of the abstract is at the end:

    We demonstrated that OR1G1 recognizes a group of odorants that share both 3D structural and perceptual qualities. We hypothesized that OR1G1 contributes to the coding of waxy, fatty, and rose odors in humans.
    Translation - they say that they can demonstrate that one particular olfactory receptor links 3-D structure (roughly, shape) and perceptive qualities for a group of molecules. They postulate that the receptor in question is a contributor to perception of certain odors.

    They also had this to say, which I find more impressive:

    We previously described the odorant repertoire of a human OR, OR1G1, identifying both agonists and antagonists. In this paper, we performed a 3D-quantitative structure–activity relationship (3D-QSAR) study of these ligands. We obtained a double-alignment model explaining previously reported experimental activities and permitting to predict novel agonists and antagonists for OR1G1. These model predictions were experimentally validated.
    Translation: they say that they (1) identified molecules that activate or block an olfactory receptor, (2) related the activity to structure, and (3) used that to predict new molecules that activated or blocked the same receptor.

    I haven't done more than skim the article yet - I assume it was strong enough to warrant publication. But in any case, my answer would be that - yes - we will know.

    Now - where does Turin stand in this? I'd say that depends. If more and more receptors are examined closely, and the current approach ("dual agonist–antagonist combinatorial coding") works better and better, then Occam's razor says there is no need for anything more. But perhaps there is something that the model doesn't explain - such as structurally disparate molecules activating the same receptor, with the only correlation being the IR energetics. Then Turin's stuff could conceivably fit in. Or his observations could just be interesting accidents. To quote the title of the recent book, "fooled by randomness". Maybe thiols and boranes just hyperactivate the same receptor type by a structural accident, and appear superficially the same, like birds and bats. Maybe they activate different receptors that are both interpreted as similar odors - another fluke. Maybe Tonkene smells like coumarin because of basic functional similarity, and not a matching IR spectrum. This is where it's important to leave behind the semi-anecdotal "leads" that point us in potential right directions, and to start getting meticulous and statistical.

    If Turin is right, then it might be possible to have a program predicting IR spectra simply crank through potential structures in search of fingerprint matches to valuable molecules, like Tonkene matches coumarin. Is that what he did there? I don't know. But it would be important to know about failures there, too, if we're being honest with ourselves.

    On the other hand, it will be important to do the same for non-Turin theories, too. Can they predict more than just a single receptor? Can we correlate a structure with the mappings of thousands of other molecules across hundreds of receptors, and predict the final odor as a function of binding to multiple receptors? I think that's an exciting possibility.

    Either way, I firmly believe - Wir müssen wissen. Wir werden wissen.
    * * * *

  45. #45

    Default Re: New study contradicts Luca Turin's theory?

    Just wanted to say that I really enjoy such posts and discussions especially the ones that explain in understandable English the scientific point of view I tend to feel put off by the tad of condescension that some scientists express when asked questions by 'common folk' So happy to see otherwise!

    Ow and I love how Turin writes too, like a 'mad scientist' :lol: I like his style and eccentricity cos he writes/talks with humor Many scientists take themselves far to seriously

  46. #46
    Moderator

    Redneck Perfumisto's Avatar
    Join Date
    Feb 2008
    Location
    Spiritually, Kansas
    Posts
    13,084
    Post Thanks / Like
    Blog Entries
    37

    Default Re: New study contradicts Luca Turin's theory?

    Quote Originally Posted by Irina View Post
    Just wanted to say that I really enjoy such posts and discussions especially the ones that explain in understandable English the scientific point of view I tend to feel put off by the tad of condescension that some scientists express when asked questions by 'common folk' So happy to see otherwise!

    Ow and I love how Turin writes too, like a 'mad scientist' :lol: I like his style and eccentricity cos he writes/talks with humor Many scientists take themselves far to seriously
    Yes, science really should be fun. That's why my favorite scientists are the gang of ex-stunt-people on MythBusters. I'm just amazed at the purity of science they put on display. So much of science has become politicized, agenda-driven, and tainted in a mild but still annoying way. And I'm not leaving myself untainted by that statement. In contrast, all those jokers on MythBusters do is seek the truth on behalf of the common man, using the scientific method straight out of the bottle. God bless 'em!

    Yes, I enjoy Turin's writing, too. Very much.

    Finally, an important point. In science, mathematics, and anything else, we tend to learn more from errors than otherwise. So even if Turin's exploration of the frequency theory is wrong in terms of explaining biological olfaction, nothing is wasted in knowledge. It's clear that Turin's work opens up all sorts of interesting scientific and technological avenues, and I hope that he finds success on at least one of them.
    * * * *

  47. #47
    Moderator

    Redneck Perfumisto's Avatar
    Join Date
    Feb 2008
    Location
    Spiritually, Kansas
    Posts
    13,084
    Post Thanks / Like
    Blog Entries
    37

    Default Re: New study contradicts Luca Turin's theory?

    Quote Originally Posted by kbe View Post
    I am going to spend a night in a Holiday Inn Express and then re-read that article.
    Still LMAO!

    Actually, I may just move into one and re-do my life.
    * * * *

  48. #48

    Default Re: New study contradicts Luca Turin's theory?

    LT claims that his company has used his thoery to come up with as non cancer-causing replacement for coumarin. When I read Burr's book, I was rooting for Turin's theory just because it would, by definition, replace millions of man hours of apparently near-random molecule creation, making possible the a flood of new scents.

    BTW, I hane only the barest-bones understanding of any of this, but I do remember reading that Buck had to retract at least part of her research because nobody has been able to duplicate it.

  49. #49

    Default Re: New study contradicts Luca Turin's theory?

    That's one thing that really annoys me; there are so many examples of this (claims that are believed in like religious doctrines) and that either don't have experimental evidence to support them or else are contradicted by undeniable experimental data that it makes one wonder why biology is taught as a science. It's often little more than a stubborn version of philosophy (not to disparage philosophy professors).

  50. #50
    beachroses's Avatar
    Join Date
    Sep 2006
    Location
    North Carolina
    Posts
    2,202
    Post Thanks / Like

    Default Re: New study contradicts Luca Turin's theory?

    Quote Originally Posted by Redneck Perfumisto View Post
    Thanks, zz. Honestly, I feel humbled to be posting in a place that Turin found worthwhile. But it's clear why he did.
    To pump his book?

    I'm not a scientist, but I do think that essences found naturally in our environment smell differently than ones manufactured in labs and maybe it is because of their vibrations. I've said that on here before. ::ducks flying glass beacons::

  51. #51
    Moderator

    Redneck Perfumisto's Avatar
    Join Date
    Feb 2008
    Location
    Spiritually, Kansas
    Posts
    13,084
    Post Thanks / Like
    Blog Entries
    37

    Default Re: New study contradicts Luca Turin's theory?

    Quote Originally Posted by beachroses View Post
    To pump his book?
    LOL! I would imagine that he came into here with the same jittery feeling as a drug-and-potion salesman pulling his wagon into Tombstone. He may have felt a bit tarred-and-feathered, but we did buy every last bottle of perfume on his wagon. And we're still debating whether this magnetism thing he believes in really will cure arthritis. I suggest that it might, but perhaps not in the way that anyone suspects!

    Quote Originally Posted by beachroses View Post
    I'm not a scientist, but I do think that essences found naturally in our environment smell differently than ones manufactured in labs and maybe it is because of their vibrations. I've said that on here before. ::ducks flying glass beacons::
    LOL - No throwing of glassware here! I won't argue with there being a difference between natural mixtures and synthetic approximations. The note identification project put any thought otherwise to rest for me. Natural essences are so complex - it's impossible to find a synthetic reconstitution that provides the same olfactory impression. I did love some of the synthetic reconstitutions. In some ways, they were easier to work with, because they seem simpler. They are often very "clean" and pure-smelling. But they're never the same as naturals. In theory, I'm sure it would be possible to duplicate a natural essence by adding in every single natural component from a very pure synthetic source in some kind of massive effort, but why bother? Just use the natural and be happy that nature made the task easy!

    One of the things I find so wonderful about science over the ages is how recurring patterns of unfolding truth show that even the people who were wrong about something were often right in other ways. The Greek philosopher Democritus believed in atoms very early, and was eerily prescient in many in his musings:

    In the fifth century B.C., Democritus, an early shapist, theorized that sweet atoms were ''round and of a good size.'' Sour ones? ''Bulky, jagged and many-angled, without curves.'' ''Whichever shape predominates,'' he explained, ''will determine what sense-impression we receive.'' -from this review of Burr's book about Turin
    Democritus was a bit too early to understand real molecules, but he was perhaps right in principle. If you think of certain molecular features called functional groups as "jaggedness", or if you view the olfactory impression of a molecule against a number N of receptors as an N-dimensional object (make it 3 to see it easily), then I would say that "spiked" and "jagged" are precisely what nasty smells tend to be - they are overwhelming ("pointed", "sharp") in some particular direction. Heck - we even use the word "sharp". Sometimes I just have to wonder how Democritus and Pythagoras cheated to know so much!
    * * * *

  52. #52

    Default Re: New study contradicts Luca Turin's theory?

    For me, it's the "vibration" that makes the nasty smells. It really feels like something is being pulled too far, like a rubber band that is being stretched to near its breaking point. However, I wouldn't suggest this is something that should be considered scientific evidence.

  53. #53
    surreality's Avatar
    Join Date
    Jun 2008
    Location
    Michigan
    Posts
    2,137
    Post Thanks / Like

    Default Re: New study contradicts Luca Turin's theory?

    Quote Originally Posted by Bigsly View Post
    It's often little more than a stubborn version of philosophy (not to disparage philosophy professors).
    Philosophers appreciate when someone bothers to rip their ideas apart, it means that we are on to something.
    Seek not the favor of the multitude; it is seldom got by honest and lawful means. But seek the testimony of few; and number not voices, but weigh them. - Immanuel Kant

  54. #54
    Moderator

    Redneck Perfumisto's Avatar
    Join Date
    Feb 2008
    Location
    Spiritually, Kansas
    Posts
    13,084
    Post Thanks / Like
    Blog Entries
    37

    Default Re: New study contradicts Luca Turin's theory?

    Quote Originally Posted by surreality View Post
    Philosophers appreciate when someone bothers to rip their ideas apart, it means that we are on to something.
    Love this answer! I think this works the same way in a lot of places!
    * * * *

  55. #55

    Default Re: New study contradicts Luca Turin's theory?

    Quote Originally Posted by surreality View Post
    Philosophers appreciate when someone bothers to rip their ideas apart....
    until everyone disagrees with them.

  56. #56
    Moderator

    Redneck Perfumisto's Avatar
    Join Date
    Feb 2008
    Location
    Spiritually, Kansas
    Posts
    13,084
    Post Thanks / Like
    Blog Entries
    37

    Default Re: New study contradicts Luca Turin's theory?

    Quote Originally Posted by helo darqness View Post
    until everyone disagrees with them.
    LOL!

    ...at which point the contrarians will start to agree!
    * * * *

  57. #57
    beachroses's Avatar
    Join Date
    Sep 2006
    Location
    North Carolina
    Posts
    2,202
    Post Thanks / Like

    Default Re: New study contradicts Luca Turin's theory?

    Quote Originally Posted by Redneck Perfumisto View Post
    I won't argue with there being a difference between natural mixtures and synthetic approximations. The note identification project put any thought otherwise to rest for me. Natural essences are so complex - it's impossible to find a synthetic reconstitution that provides the same olfactory impression. I did love some of the synthetic reconstitutions. In some ways, they were easier to work with, because they seem simpler. They are often very "clean" and pure-smelling.
    Scientists discovered that natural essences from tea tree, geranium, lavender and verbena destroy that antibiotic resistant staph infection killing people in hospitals, because it is not able to develop a resistance to their complex natural structures. They also repel mosquitoes and are the main notes I wear here in the summer.

    I don't mind fragrances that combine natural essences with some synthetics, it's the 100% synthetic ones that don't give me the vibes for long. They end up in the back of my cabinet and eventually dumped on Ebay or donated. It's not that they don't smell good, it's that I tire of them easily. They lack "soul." They're usually the ones buyers go after first, too, so somebody likes them.

  58. #58
    surreality's Avatar
    Join Date
    Jun 2008
    Location
    Michigan
    Posts
    2,137
    Post Thanks / Like

    Default Re: New study contradicts Luca Turin's theory?

    Quote Originally Posted by helo darqness View Post
    until everyone disagrees with them.
    If everyone disagress with you and they bother to critique your ideas then you REALLY know you are onto something...

    Originally posted by Redneck Perfumisto

    even if Turin's exploration of the frequency theory is wrong in terms of explaining biological olfaction, nothing is wasted in knowledge.
    Exactly, even if Turin is wrong, his ideas have added to the body of scientific knowledge and prompted people to look into new areas of scientific investigation that may have unexpected outcomes.
    Last edited by surreality; 1st February 2009 at 07:50 PM.
    Seek not the favor of the multitude; it is seldom got by honest and lawful means. But seek the testimony of few; and number not voices, but weigh them. - Immanuel Kant

  59. #59

    Default Re: New study contradicts Luca Turin's theory?

    Quote Originally Posted by surreality View Post
    If everyone disagress with you and they bother to critique your ideas then you REALLY know you are onto something...

    not always.

    not saying turin is wrong, but if someone goes around telling everyone something that is OBVIOUSLY false, such as "pulp fiction had john travolta and danny glover" or columbus was on the may flower, or chuck yeager was the first man on the moon or....whatever...

    when they ARENT onto something, people will argue with them, loudly.

    especially with creationists and people who think jesus rode with dinosaurs and want to teach this in schools...

    people will stand up and not put up with bullsh*t.

  60. #60
    Moderator

    Redneck Perfumisto's Avatar
    Join Date
    Feb 2008
    Location
    Spiritually, Kansas
    Posts
    13,084
    Post Thanks / Like
    Blog Entries
    37

    Default Re: New study contradicts Luca Turin's theory?

    Quote Originally Posted by surreality View Post
    If everyone disagress with you and they bother to critique your ideas then you REALLY know you are onto something...
    Quote Originally Posted by helo darqness View Post
    not always.

    not saying turin is wrong, but if someone goes around telling everyone something that is OBVIOUSLY false, such as "pulp fiction had john travolta and danny glover" or columbus was on the may flower, or chuck yeager was the first man on the moon or....whatever...

    when they ARENT onto something, people will argue with them, loudly.

    especially with creationists and people who think jesus rode with dinosaurs and want to teach this in schools...

    people will stand up and not put up with bullsh*t.
    OK, I find myself agreeing with both of you here. Generally, people will try to ignore the folks who are so far off base that they're not making sense. To borrow the book title from the now-famous physics phrase, "not even wrong". E.g., the 6000 year-old Earth people (who are the flat Earthers of the 21st century). The trouble is, when those folks use politics to bring that junk into science, then we have to make a big fuss, like it or not. But trust me, if they were just holding meetings and whatnot and not trying to make everybody else listen to that stuff, they would be totally ignored.

    But you're probably also right, h_d, in that it's a bit different on the internet. People seem more willing to just say whatever they think (), and people are also more willing to talk back honestly to anything they disagree with. I personally love that aspect of web culture, since it promotes more vigorous discussion of ideas. When all parties are open to changing their minds based on the evidence, and everything is up for discussion without preconditions, huge progress can be made toward understanding.

    beachroses - I know what you're saying about those purely synthetic frags. I find them difficult to wear, sometimes - I almost dread putting them on.
    * * * *

Similar Threads

  1. A question for those who've read Luca Turin's book
    By Amit in forum Male Fragrance Discussion
    Replies: 7
    Last Post: 9th June 2008, 08:46 PM
  2. Luca Turin's old Blog and Top Ten
    By rtamara41 in forum Female Fragrance Discussion
    Replies: 13
    Last Post: 23rd October 2007, 02:53 PM
  3. Let's play "What's on Luca Turin's shelf?" that's in your Wardrobe?
    By mikeperez23 in forum Male Fragrance Discussion
    Replies: 13
    Last Post: 24th May 2007, 11:14 PM
  4. Luca Turin's "Crack 'o Doom" frags?
    By UngerWoo in forum Male Fragrance Discussion
    Replies: 12
    Last Post: 6th January 2007, 05:03 AM
  5. Study looks at Turin's smell theory
    By socalwoman in forum Female Fragrance Discussion
    Replies: 1
    Last Post: 29th March 2005, 08:13 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •