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简介：Adultstem/progenitorcellsplayimportantrolesintissuehomeostasisandhaveimportantimplicationsforregenerativemedicine.Itwasoncethoughtthatformationofnewbloodvesselsinadultonlyoccursthroughangiogenesis,aprocesswherebynewvesselsareformedfromexistingmatureendothelialcells;whilevasculogenesis,wherenewvesselsarederivedfromdifferentiationofendothelialprogenitorcells(EPCs),wasthoughttooccurexclusivelyinembryos.ThediscoveryofadultEPCsafewyearsagohaschangedthisoldparadigm;andsubsequentstudiesshowedthatEPCsmaybeapromisingtoolforthetreatmentofvasculardisorders.However,therehavebeenconflictingreportsonsubtypes,surfacemarkers,andfunctionsofEPCs;andthustheexactoriginandidentityofEPCsremaintobedefined.AcommonapproachtoobtainEPCsistoisolateandculturemononuclearcellsfromperipheralbloodandtoselectadherentcellsfor

简介：Haveyoueverimaginedthatyoucouldbecloned(克隆)likeDollythesheepinthenottoodistantfuture?

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简介：Inthispaper,theinterestingdevelopmentoftheveryimportantinnovationofthrustvestoringtechnologyinappliedaerodynamicsisdescribed.InMemoryofafirend.Dr.W.HerbstofMBB,Germany,theso-calledfatheroftheX-31experimentalthrustvectoringfighter,wholosthislifeafewyearsagowhilepilotinghisprivateairplane.BertrandRussel：“Menarebornignorant,notstupid-theyaremadestupidbyeducation.”.AdmiralHymanRickover:“Thebestengineersarethosewho,inadditiontotechnicalexpertise,havehadgoodtrainingintheliberalartsandunderstandtheworldaroundthem”。

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简介：本文认为,自由民主或代议制民主在现代英国的出现不是一件轻而易举的事情,其成功是因为它是与社会稳定的保持和对所有人经济福利的关注相伴而生的。作者考察了英国1768—1848年间的民主改革主张和改革运动,并以此说明英国民主改革的艰难以及在英国建立一个更加公平、稳定和民主的制度所需的前提条件。这些条件包括:城市化社会的出现、发达的经济、社会的稳定和各种代表制度的存在以及法治、宗教宽容和对公民权利的尊重等等。到18世纪末期,这些在英国都已出现,从而使激进分子可以提出让所有成年人投票并发挥政治影响的主张。这一民主运动在1848年前的几十年里一直没有获得成功,部分是因为保守的批评者们认为民主会威胁社会稳定并削弱法律和秩序,同时也是由于早期的社会主义思想家们认为民主改革并不足以把大众从经济贫困和社会压迫中拯救出来。作者在结论中指出,英国在1848年后的几十年时间里逐渐成为一个更公平、稳定和民主的社会,这部分是因为民主改革家们的成功主张和努力,同时也是由于人们认识到,民主必须与社会稳定的维护以及法律和秩序相伴,而且,在追求民主的同时也需要进行社会福利改革以改善穷人的经济生活。

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简介：ChenYifan,whoisresolvedtobesingleforlife,hasneverexpectedthatat45,shecanrealizeherdreamofproducingababyforherselfwithouthavingtogetmarried—andlegally.ThewomanisquitesuccessfulinhercareerasmanagerofaprivatecompanyinChangchunCity,JilinProvince,northeastChina.Herpersonallife,however,isnot.Shefellinlovewithaclassmatebackintheearly1980s,andwasheart-brokenwhentheyoungmanlefther.Sincethen,thewomanhasfoundthatnomaninthisworldisgoodenoughtobeherhusband.Thoughsingle,shewantstohaveachildofherown.'I’llbeburningwithenvywheneverIseea

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简介：Overalongperiodoftime,thestabilityanddevelopmentoftheSino-U.S.relationshiphasbeensubjectedtointerferenceanddisruptionbyrepeateddisputesandfrictionsovertheU.S.armssalestoTaiwan.However,intheUnitedStates,therehasbeennotmuchdivergenceofviewsconcerningtheU.S.arms