1.Thefailureofahigh-profilecholesteroldrughasthrownaspotlightonthecomplicatedmachinerythatregulatescholesterollevels.Butmanyresearchersremainconfidentthatdrugstoboostlevelsof'good'cholesterolarestilloneofthemostpromisingmeanstocombatspirallingheartdisease.
2.DrugcompanyPfizerannouncedon2Decemberthatitwascancellingallclinicaltrialsoftorcetrapib，adrugdesignedtoraiseheart-protectivehigh-densitylipoproteins(HDLs).Inatrialof15000patients，asafetyboardfoundthatmorepeoplediedorsufferedcardiovascularproblemsaftertakingthedrugplusacholesterol-loweringstatinthanthoseinacontrolgroupwhotookthestatinalone.
3.Thenewscameasakickintheteethtomanycardiologistsbecauseearliertestsinanimalsandpeoplesuggesteditwouldlowerratesofcardiovasculardisease."Therehavebeennoredflagstomyknowledge,"saysJohnChapman，aspecialistinlipoproteinsandatherosclerosisattheNationalInstituteforHealthandMedicalResearch(INSERM)inPariswhohasalsostudiedtorcetrapib."Thiscancellationcameasacompleteshock."
4.TorcetrapibisoneofthemostadvancedofanewbreedofdrugsdesignedtoraiselevelsofHDLs，whichferrycholesteroloutofartery-cloggingplaquestotheliverforremovalfromthebody.Specifically，torcetrapibblocksaproteincalledcholesterolestertransferprotein(CETP)，whichnormallytransfersthecholesterolfromhigh-densitylipoproteinstolowdensity，plaque-promotingones.Statins，incontrast，mainlyworkbyloweringthe'bad'low-densitylipoproteins.
Underpressure
5.Researchersarenowtryingtoworkoutwhyandhowthedrugbackfired，somethingthatwillnotbecomeclearuntiltheclinicaldetailsarereleasedbyPfizer.Onehintliesinevidencefromearliertrialsthatitslightlyraisesbloodpressureinsomepatients.Itwasthoughtthatthismildproblemwouldbeoffsetbytheheartbenefitsofthedrug.Butitispossiblethatitactuallyprovedfatalinsomepatientswhoalreadysufferedhighbloodpressure.Ifbloodpressureistheexplanation，itwouldactuallybegoodnewsfordrugdevelopersbecauseitsuggeststhattheproblemsarespecifictothiscompound.OtherprototypedrugsthatarebeingdevelopedtoblockCETPworkinaslightlydifferentwayandmightnotsufferthesamedownfall.
6.ButitisalsopossiblethatthewholeideaofblockingCETPisflawed，saysMotiKashyap，whodirectsatherosclerosisresearchattheVAMedicalCenterinLongBeach，California.WhenHDLsexcretecholesterolintheliver，theyactuallyrelyonLDLsforpartofthisprocess.SoinhibitingCETP，whichpreventsthetransferofcholesterolfromHDLtoLDL，mightactuallycauseanabnormalandirreversibleaccumulationofcholesterolinthebody."You'reblockingaphysiologicmechanismtoeliminatecholesterolandeffectivelyconstipatingthepathway,"saysKashyap.Goingup
7.Mostresearchersremainconfidentthatelevatinghighdensitylipoproteinslevelsbyonemeansoranotherisoneofthebestroutesforhelpingheartdiseasepatients.ButHDLsarecomplexandnotentirelyunderstood.Oneapproveddrug，calledniacin，isknowntobothraiseHDLandreducecardiovascularriskbutalsocausesanunpleasantsensationofheatandtingling.Researchersareexploringwhethertheycanbypassthissideeffectandwhetherniacincanlowerdiseaseriskmorethanstatinsalone.Scientistsarealsoworkingonseveralothermeanstobumpuphigh-densitylipoproteinsby，forexample，introducingsyntheticHDLs."Theonlythingw
Thereisamixtureofpeoplefromdifferentculturesandethnicgroupsinacountry.Why?Isthisapositiveornegativedevelopment?
1.AEuropeanspacecrafttookofftodaytospearheadthesearchforanother"Earth"amongthestars.
2.TheCorotspacetelescopeblastedoffaboardaRussianSoyuzrocketfromtheBaikonurcosmodromeinKazakhstanshortlyafter2.20pm.
3.Corot,shortforconvectionrotationandplanetarytransits,isthefirstinstrumentcapableoffindingsmallrockyplanetsbeyondthesolarsystem.Anysuchplanetsituatedintherightorbitstandsagoodchanceofhavingliquidwateronitssurface,andquitepossiblylife,althoughaleadingscientistinvolvedintheprojectsaiditwasunlikelytofind"anylittlegreenmen".
4.DevelopedbytheFrenchspaceagency,CNES,andpartneredbytheEuropeanSpaceAgency(ESA),Austria,Belgium,Germany,BrazilandSpain,Corotwillmonitoraround120,000starswithits27cmtelescopefromapolarorbit514milesabovetheEarth.Overtwoandahalfyears,itwillfocusonfivetosixdifferentareasofthesky,measuringthebrightnessofabout10,000starsevery512seconds.
5."Atthepresentmomentwearehopingtofindoutmoreaboutthenatureofplanetsaroundstarswhicharepotentialhabitats.Wearelookingathabitableplanets,notinhabitedplanets.Wearenotgoingtofindanylittlegreenmen,"ProfessorIanRoxburgh,anESAscientistwhohasbeeninvolvedwithCorotsinceitsinception,toldtheBBCRadio4Todayprogramme.
6.ProfRoxburghsaiditwashopedCorotwouldfind"rockyplanetsthatcoulddevelopanatmosphereand,iftheyaretherightdistancefromtheirparentstar,theycouldhavewater".
7.Tosearchforplanets,thetelescopewilllookforthedimmingofstarlightcausedwhenanobjectpassesinfrontofastar,knownasa"transit".Althoughitwilltakemoresophisticatedspacetelescopesplannedinthenext10yearstoconfirmthepresenceofanEarth-likeplanetwithoxygenandliquidwater,Corotwillletscientistsknowwheretopointtheirlenses.
8.MeasurementsofminutechangesinbrightnesswillenablescientiststodetectgiantJupiter-likegasplanetsaswellassmallrockyones.Itistherockyplanets-thatcouldbenobiggerthanabouttwicethesizeoftheEarth-whichwillcausethemostexcitement.Scientistsexpecttofindbetween10and40ofthesesmallerplanets.
9.Corotwillalsoprobeintostellarinteriorsbystudyingtheacousticwavesthatrippleacrossthesurfaceofstars,atechniquecalled"asteroseismology".
10.Thenatureoftheripplesallowsastronomerstocalculateastar’sprecisemass,ageandchemicalcomposition.
11."Aplanetpassinginfrontofastarcanbedetectedbythefallinlightfromthatstar.Smalloscillationsofthestaralsoproducechangesinthelightemitted,whichrevealwhatthestarismadeofandhowtheyarestructuredinternally.Thisdatawillprovideamajorboosttoourunderstandingofhowstarsformandevolve,"ProfRoxburghsaid.
12.Sincethediscoveryin1995ofthefirst"exoplanet"-aplanetorbitingastarotherthantheSun-morethan200othershavebeenfoundbyground-basedobservatories.
13.Untilnowtheusualmethodoffindingexoplanetshasbeentodetectthe"wobble"theirgravityimpartsonparentstars.ButonlygiantgaseousplanetsbiggerthanJupitercanbefoundthisway,andtheyareunlikelytoharbourlife.
14.Inthe2010s,ESAplanstolaunchDarwin,afleetoffourorfiveinterlinkedspacetelescopesthatwillnotonlyspot
Nowadaysitismoreconvenientandeasierforpeopletotraveltoothercountries.Doyouthinkthepositiveeffectsexceedthenegativeeffects?
newweapontofightcancer
1.Britishscientistsarepreparingtolaunchtrialsofaradicalnewwaytofightcancer,whichkillstumoursbyinfectingthemwithviruseslikethecommoncold.
2.Ifsuccessful,virustherapycouldeventuallyformathirdpillaralongsideradiotherapyandchemotherapyinthestandardarsenalagainstcancer,whileavoidingsomeofthedebilitatingside-effects.
3.LeonardSeymour,aprofessorofgenetherapyatOxfordUniversity,whohasbeenworkingonthevirustherapywithcolleaguesinLondonandtheUS,willleadthetrialslaterthisyear.CancerResearchUKsaidyesterdaythatitwasexcitedbythepotentialofProfSeymour’spioneeringtechniques.
4.Oneofthecountry’sleadinggeneticists,ProfSeymourhasbeenworkingwithvirusesthatkillcancercellsdirectly,whileavoidingharmtohealthytissue."Inprinciple,you’vegotsomethingwhichcouldbemanytimesmoreeffectivethanregularchemotherapy,"hesaid.
5.Cancer-killingvirusesexploitthefactthatcancercellssuppressthebody’slocalimmunesystem."Ifacancerdoesn’tdothat,theimmunesystemwipesitout.Ifyoucangetavirusintoatumour,virusesfindthemaverygoodplacetobebecausethere’snoimmunesystemtostopthemreplicating.Youcanregarditasthecancer’sAchilles’heel."
6.Onlyasmallamountofthevirusneedstogettothecancer."Theyreplicate,yougetamillioncopiesineachcellandthecellburstsandtheyinfectthetumourcellsadjacentandrepeattheprocess,"saidProfSeymour.
7.Preliminaryresearchonmiceshowsthatthevirusesworkwellontumoursresistanttostandardcancerdrugs."It’saninterestingpossibilitythattheymayhaveanadvantageinkillingdrug-resistanttumours,whichcouldbequitedifferenttoanythingwe’vehadbefore."
8.Researchershaveknownforsometimethatvirusescankilltumourcellsandsomeaspectsoftheworkhavealreadybeenpublishedinscientificjournals.Americanscientistshavepreviouslyinjectedvirusesdirectlyintotumoursbutthistechniquewillnotworkifthecancerisinaccessibleorhasspreadthroughoutthebody.
9.ProfSeymour’sinnovativesolutionistomaskthevirusfromthebody’simmunesystem,effectivelyallowingthevirusestodowhatchemotherapydrugsdo-spreadthroughthebloodandreachtumourswherevertheyare.Thebighurdlehasalwaysbeentofindawaytodelivervirusestotumoursviathebloodstreamwithoutthebody’simmunesystemdestroyingthemontheway.
10."Whatwe’vedoneismakechemicalmodificationstothevirustoputapolymercoataroundit-it’sastealthviruswhenyouinjectit,"hesaid.
11.Afterthestealthvirusinfectsthetumour,itreplicates,butthecopiesdonothavethechemicalmodifications.Iftheyescapefromthetumour,thecopieswillbequicklyrecognisedandmoppedupbythebody’simmunesystem.
12.Thetherapywouldbeespeciallyusefulforsecondarycancers,calledmetastases,whichsometimesspreadaroundthebodyafterthefirsttumourappears."There’sanawfulstatisticofpatientsinthewest...withmalignantcancers;75%ofthemgoontodiefrommetastases,"saidProfSeymour.
13.Twovirusesarelikelytobeexaminedinthefirstclinicaltrials:adenovirus,whichnormallycausesacold-likeillness,andvaccinia,whichcausescowpoxandisalsousedinthevaccineagainstsmallpox.Forsafetyreasons,bothwillbedisabledtomakethe