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Rogue theory of smell gets a boost
1.A controversial theory of how we smell, which claims that our fine sense of
odour depends on quantum mechanics, has been given the thumbs up by a team of
physicists.
2.Calculations by researchers at University College London (UCL) show that
the idea that we smell odour molecules by sensing their molecular vibrations
makes sense in terms of the physics involved.
3.That's still some way from proving that the theory, proposed in the
mid-1990s by biophysicist Luca Turin, is correct.But it should make other
scientists take the idea more seriously.
4."This is a big step forward," says Turin, who has now set up his own
perfume company Flexitral in Virginia.He says that since he published his
theory, "it has been ignored rather than criticized."
5.Most scientists have assumed that our sense of smell depends on receptors
in the nose detecting the shape of incoming molecules, which triggers a signal
to the brain.This molecular 'lock and key' process is thought to lie behind a
wide range of the body's detection systems: it is how some parts of the immune
system recognise invaders, for example, and how the tongue recognizes some
tastes.
6.But Turin argued that smell doesn't seem to fit this picture very
well.Molecules that look almost identical can smell very different — such as
alcohols, which smell like spirits, and thiols, which smell like rotten eggs.And
molecules with very different structures can smell similar.Most strikingly, some
molecules can smell different — to animals, if not necessarily to humans —
simply because they contain different isotopes (atoms that are chemically
identical but have a different mass).
7.Turin's explanation for these smelly facts invokes the idea that the smell
signal in olfactory receptor proteins is triggered not by an odour molecule's
shape, but by its vibrations, which can enourage an electron to jump between two
parts of the receptor in a quantum-mechanical process called tunnelling.This
electron movement could initiate the smell signal being sent to the brain.
8.This would explain why isotopes can smell different: their vibration
frequencies are changed if the atoms are heavier.Turin's mechanism, says
Marshall Stoneham of the UCL team, is more like swipe-card identification than a
key fitting a lock.
9.Vibration-assisted electron tunnelling can undoubtedly occur — it is used
in an experimental technique for measuring molecular vibrations."The question is
whether this is possible in the nose," says Stoneham's colleague, Andrew
Horsfield.
10.Stoneham says that when he first heard about Turin's idea, while Turin was
himself based at UCL, "I didn't believe it".But, he adds, "because it was an
interesting idea, I thought I should prove it couldn't work.I did some simple
calculations, and only then began to feel Luca could be right." Now Stoneham and
his co-workers have done the job more thoroughly, in a paper soon to be
published in Physical Review Letters.
11.The UCL team calculated the rates of electron hopping in a nose receptor
that has an odorant molecule bound to it.This rate depends on various properties
of the biomolecular system that are not known, but the researchers could
estimate these parameters based on typical values for molecules of this
sort.
12.The key issue is whether the hopping rate with the odorant in place is
significantly greater than that without it.The calculations show that it is —
which means that odour identification in this way seems theoretically
possible.
13.But Horsfield stresses that that's different from a proof of Turin's
idea."So far things look plausible, but we need proper experimental
verification.We're beginning to think about what experiments could be
performed."
14.Meanwhile, Turin is pressing ahead with his hypothesis."At Flexitral we
have been designing odorants exclusively on the basis of their computed
vibrations," he says."Our success rate at odorant discovery is two orders of
magnitude better than the competition." At the very least, he is putting his
money where his nose is.
Questions 5-9
Complete the sentences below with words from the passage.Use NO MORE THAN
THREE WORDS for each answer.
5.The hypothesis that we smell by sensing the molecular vibration was made by
______.
6.Turin's company is based in ______.
7.Most scientists believed that our nose works in the same way as our
______.
8.Different isotopes can smell different when ______ weigh differently.
9.According to Audrew Horsfield, it is still to be proved that ______ could
really occur in human nose.
Felicity Lawrence
Thursday December 28, 2006
The Guardian
1. Consumers are to be presented with two rival new year advertising
campaigns as the Food Standards Agency goes public in its battle with the
industry over the labelling of unhealthy foods.
2. The Guardian has learned that the FSA will launch a series of 10-second
television adverts in January telling shoppers how to follow a red, amber and
green traffic light labelling system on the front of food packs, which is
designed to tackle Britain’s obesity epidemic.
3. The campaign is a direct response to a concerted attempt by leading food
manufacturers and retailers, including Kellogg’s and Tesco, to derail the
system. The industry fears that traffic lights would demonise entire categories
of foods and could seriously damage the market for those that are fatty, salty
or high in sugar.
4. The UK market for breakfast cereals is worth ￡1.27bn a year and the
manufacturers fear it will be severely dented if red light labels are put on
packaging drawing attention to the fact that the majority are high in salt
and/or sugar.
5. The industry is planning a major marketing campaign for a competing
labelling system which avoids colour-coding in favour of information about the
percentage of "guideline daily amounts" (GDAs) of fat, salt and sugar contained
in their products.
6. The battle for the nation’s diet comes as new rules on television
advertising come into force in January which will bar adverts for unhealthy
foods from commercial breaks during programmes aimed at children. Sources at the
TV regulators are braced for a legal challenge from the industry and have
described the lobbying efforts to block any new ad ban or colour-coded labelling
as "the most ferocious we’ve ever experienced".
7. Ofcom’s chief executive, Ed Richards, said: "We are prepared to face up to
any legal action from the industry, but we very much hope it will not be
necessary." The FSA said it was expecting an onslaught from the industry in
January. Senior FSA officials said the manufacturers’ efforts to undermine its
proposals on labelling could threaten the agency’s credibility.
8. Terrence Collis, FSA director of communications, dismissed claims that the
proposals were not based on science. "We have some of the most respected
scientists in Europe, both within the FSA and in our independent advisory
committees. It is unjustified and nonsensical to attack the FSA’s scientific
reputation and to try to undermine its credibility."
9. The FSA is understood to have briefed its ad agency, United, before
Christmas, and will aim to air ads that are "non-confrontational, humorous and
factual" as a counterweight to industry’s efforts about the same time. The
agency, however, will have a tiny fraction of the budget available to the
industry.
10. Gavin Neath, chairman of Unilever UK and president of the Food and Drink
Federation, has said that the industry has made enormous progress but could not
accept red "stop" signs on its food.
11. Alastair Sykes, chief executive of Nestlé UK, said that under the FSA
proposals all his company’s confectionery and most of its cereals would score a
red. "Are we saying people shouldn’t eat confectionery? We’re driven by
consumers and what they want, and much of what we do has been to make our
products healthier," he said.
12. Chris Wermann, director of communications at Kellogg’s, said: "In
principle we could never accept traffic light labelling."
13. The rival labelling scheme introduced by Kellogg’s, Danone, Unilever,
Nestlé, Kraft and Tesco and now favoured by 21 manufacturers, uses an
industry-devised system based on identifying GDAs of key nutrients. Tesco says
it has tested both traffic lights and GDA labels in its stores and that the
latter increased sales of healthier foods.
14. But the FSA said it could not live with this GDA system alone because it
was "not scientific" or easy for shoppers to understand at a glance.
Questions 1-6
Answer the questions below using NO MORE THAN THREE WORDS from the passage
for each answer.
1. When will instructions be given on reading the color-coded labels?
2. Where can customers find the red light labels?
3. What problem is the FSA trying to handle with the labeling system?
4. Which product sells well but may not be healthy?
5. What information, according to the manufacturers, can be labeled on
products?
6. What can not be advertised during children’s programmes?
Questions 7-13
Use the information in the text to match the people (listed A-E) with the
opinions (listed 7-13) below. Write the appropriate letter (A-E) for questions
1-7.
NB You may use any letter more than once.
A Ed Richard
B Terrence Collis
C Gavin Neath
D Alastair Sykes
E Chris Wermann
7. Generally we will not agree to use the red light labels.
8. It is unreasonable to doubt if FSA is trustworthy.
9. We are trying to meet our consumers’ needs.
10. The food industry has been improving greatly.
11. The color-coded labeling system is scientific.
12. Our products will be labeled unhealthy by the FSA.
13. We are ready to confront the manufacturers.
