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1、1.RogueTheoryofSmellgetsaBoostPublishedonline:6December2006Roguetheoryofsmellgetsaboost1.Acontroversialtheoryofhowwesmell,whichclaimsthatourfinesenseofodourdependsonquantummechanics,hasbeengiventhethumbsupbyateamofphysicists.2.CalculationsbyresearchersatUniversity
2、CollegeLondon(UCL)showthattheideathatwesmellodourmoleculesbysensingtheirmolecularvibrationsmakessenseintermsofthephysicsinvolved.3.That'sstillsomewayfromprovingthatthetheory,proposedinthemid-1990sbybiophysicistLucaTurin,iscorrect.Butitshouldmakeotherscientiststake
3、theideamoreseriously.4."Thisisabigstepforward,"saysTurin,whohasnowsetuphisownperfumecompanyFlexitralinVirginia.Hesaysthatsincehepublishedhistheory,"ithasbeenignoredratherthancriticized."5.Mostscientistshaveassumedthatoursenseofsmelldependsonreceptorsinthenosedetec
4、tingtheshapeofincomingmolecules,whichtriggersasignaltothebrain.Thismolecular'lockandkey'processisthoughttoliebehindawiderangeofthebody'sdetectionsystems:itishowsomepartsoftheimmunesystemrecogniseinvaders,forexample,andhowthetonguerecognizessometastes.6.ButTurinarg
5、uedthatsmelldoesn'tseemtofitthispictureverywell.Moleculesthatlookalmostidenticalcansmellverydifferent—suchasalcohols,whichsmelllikespirits,andthiols,whichsmelllikerotteneggs.Andmoleculeswithverydifferentstructurescansmellsimilar.Moststrikingly,somemoleculescansmel
6、ldifferent—toanimals,ifnotnecessarilytohumans—simplybecausetheycontaindifferentisotopes(atomsthatarechemicallyidenticalbuthaveadifferentmass).7.Turin'sexplanationforthesesmellyfactsinvokestheideathatthesmellsignalinolfactoryreceptorproteinsistriggerednotbyanodourm
7、olecule'sshape,butbyitsvibrations,whichcanencourageanelectrontojumpbetweentwopartsofthereceptorinaquantum-mechanicalprocesscalledtunnelling.Thiselectronmovementcouldinitiatethesmellsignalbeingsenttothebrain.8.Thiswouldexplainwhyisotopescansmelldifferent:theirvibra
8、tionfrequenciesarechangediftheatomsareheavier.Turin'smechanism,saysMarshallStonehamoftheUCLteam,ismorelikeswipe-cardidentificationthanakeyfittingalock.9
