学科分类
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92 个结果
  • 简介:Alongwiththeprogressinbreadthanddepthofinternationalarmscontrolanddisarmament,US-ledWesternnationsareincreasinglyinneedofChina’sco-operation.TheybegantoseekconsultationsandcoordinationwithChina.ThishasledtoChina’sbiggersayandrisingroleininternationalarmscontrol.

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  • 简介:Inessence,twoepoch-makingeventsarereshapingtheworldordertoday:thecollapseoftheoldSovietblocandtheriseofAsia-Pacific,ofwhichChina’seco-nomictakeoffconstitutesanimportantpart.WhiletheformerbroughtanendtotheEast-WestColdWar,thelatterismakingtremendouscontributionstowards

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  • 简介:Nitricoxide(NO)isapleiotropicregulator,criticaltonumerousbiologicalprocesses,includingva-sodilatation,neurotransmissionandmacrophage-mediatedimmunity.Thefamilyofnitricoxidesynthases(NOS)comprisesinducibleNOS(iNOS),endothelialNOS(eNOS),andneuronalNOS(nNOS).Interest-ingly,variousstudieshaveshownthatallthreeisoformscanbeinvolvedinpromotingorinhibitingtheetiologyofcancer.NOSactivityhasbeendetectedintumourcellsofvarioushistogeneticoriginsandhasbeenassociatedwithtumourgrade,proliferationrateandexpressionofimportantsignalingcomponentsassociatedwithcancerdevelopmentsuchastheoestrogenreceptor.ItappearsthathighlevelsofNOSexpression(forexample,generatedbyactivatedmacrophages)maybecytostaticorcytotoxicfortumorcells,whereaslowlevelactivitycanhavetheoppositeeffectandpromotetumourgrowth.Paradoxicallytherefore,NO(andrelatedreactivenitrogenspecies)mayhavebothgenotoxicandangiogenicproperties.IncreasedNO-generationinacellmayselectmutantp53cellsandcontributetotumourangiogenesisbyupregulatingVEGF.Inaddition,NOmaymodulatetumourDNArepairmechanismsbyupregulatingp53,poly(ADP-ribose)polymerase(PARP)andtheDNA-dependentproteinkinase(DNA-PK).Anunderstand-ingatthemolecularleveloftheroleofNOincancerwillhaveprofoundtherapeuticimplicationsforthediagnosisandtreatmentofdisease.

  • 标签: 癌症 一氧化碳 合成酶 表达程度 受体
  • 简介:Coldringrollingisanadvancedbutcomplexmetalformingprocessundercoupledeffectswithmulti-factors,suchasgeometrysizesofrollsandringblank,material,formingprocessparametersandfriction,etc.Amongthesefactors,frictionbetweenrollsandringblankplaysanimportantroleinkeepingthestableformingofcoldringrolling.Ananalyticalmethodwasfirstlypresentedforproximatelydeterminingthecriticalfrictioncoefficientofstableformingandthenamethodwasproposedtodeterminethecriticalfrictioncoefficientbycombininganalyticalmethodwithnumericalsimulation.Andtheinfluenceoffrictioncoefficientonthequalityofend-planeandsidespreadofring,rollingforce,rollingmomentandmetalflowcharacteristicinthecoldringrollingprocesshavebeenexploredusingthethreedimensional(3D)numericalsimulationbasedontheelastic-plasticdynamicfiniteelementmethod(FEM)undertheABAQUSsoftwareenvironment,andtheresultsshowthatincreasingthefrictiononthecontactsurfacesbetweenrollsandringblankisusefulnotonlyforimprovingthestabilityofcoldringrollingbutalsoforimprovingthegeometryanddimensionprecisionofdeformedring.

  • 标签: 复合金属 弹塑性 动态分析 FEM 临界摩擦力
  • 简介:ROLEOFWOMENINSOCIALFORESTRYPROJECTbyYuanGuoshengSinceitsimplementationin1992,theFujianShouningSocialForestryProjectgovernment...

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  • 简介:AnumberofresearchprogramshavebeenestablishedtoevaluatepotentialapplicationsofconstructedwetlandsinWesternAustralia.Theseconstructedwetlandsareknownnotonlyfortheirnutrientremovalcapability,butalsotheirroleinhabitatcreation,urbanlandscapingandwaterqualityandenvironmentalhealth.Theyplayanimportantroleinthereductionofnutrients,particularlyphosphorous,fromenteringthewaterways.ThispaperreportsontheimprovementofwaterqualityinthePeelMainDrainbeforeitsdisposalintothePeelEstuary,Perth,WesternAustralia.Thenitrogentophosphorous(N:P)ratiowasbelowthecriticallimitduringsummer(dryspell)andthesystemwaslimitedbynitrogen.Theconcentrationofphosphoruswashighinsummerandlowinwinterduetoincreasedavailabilityofdissolvedoxygeninwinter.AwetlandwasproposedtoimprovethewaterqualityinthePeelMainDrainusingvegetationandsubstrate.Thehydrologiceffectivenesswasfoundtobe78%foradetentiontimeof30hours.Itisexpectedthatthemaximumnitrogenremovalefficiencyoftheconstructedwetlandwillbe80%withanestimatedefficiencyof40%inthefirstyearand60-80%inthesubsequentyears.Forphosphorousitisexpectedthattheconstructedwetlandwillbeeffectiveinremovingfilterablereactivephosphorous.TraditionalsedimentremediationtechniqueshavebeenfoundunsuitableforthelongtermbindingofthephosphorousthereforetheuseofPhoslockTMisrecommended.

  • 标签: 湿地 富营养化 环境保护 水资源
  • 简介:Astheprogressofvascularsurgery,artificialvesselshavebecomethesubstituteforlargeandmiddlediametervesselsbuthavenotforsmalldiameteronesowingtothrombogenesisandocclusionwithinashortperiodoftimeafterbeingapplied.ArtificialvesselendothelializationisoneoftheidealmethodstoresolvesuchissueandhasbeenimprovedcontinuouslysinceHerring1in1978putforwardthisterminthefirsttimeandutilizedvascularendothelialcells(ECs)harvestedfromlivinganimalstoperformthetestofartificialvesselendothelialization.

  • 标签: 角色 预涂渍 人造血管 内皮化 外科手术
  • 简介:OfflineSoftwaresuchasSimulation,Reconstruction,Analysis,andVisualisationareallinneedofadetectordescription.Theseapplicationshaveseveralcommonbutalsomanyspecificrequirementsforthedetectordescriptioninordertobuilduptheirinternalrepresentations.Toachievethisinaconsistentandcoherentmanneracommonsourceofinformation,thedetectordescriptiondatabase,willbeconsultedbyeachoftheapplications.TheroleandsuitabilityofXMLinthedesignofthedetectordescriptiondatabaseinthescopeoftheCMSdetectorattheLHCisdiscussed.DifferentaspectssuchasdatamodellingcapabilitiesofXML,toolsupport,integrationtoC++representationsofdatamodelsaretreatedandrecentresultsofprototypeimplementationsarepresented.

  • 标签: CMS 检测器描述数据库 脱机软件 XML
  • 简介:Matrixmetalloproteinases(MMPs)andtissueinhibitorsofmetalloproteinases(TIMPs)playasignificantroleinregulatingangiogenesis,theprocessofnewbloodvesselformation.Interstitialcollagenase(MMP-1),72kDagelatinaseA/typeIVcollagenase(MMP-2),and92kDAgelatinaseB/typeIVcollagenase(MMP-9)dissolveextracellularmatrix(ECM)andmayinitiateandpromoteangiogenesis.TIMP-1,TIMP-2,TIMP-3,andpossibly,TIMP-4inhibitneovascularization.Anewparadignisemergingthatmatrilysin(MMP-7),MMP-9,andmetalloelastase(MMP-12)mayblockangiogenesisbyconvertingplasminogentoangiostatin,whichisoneofthemostpotentangiogenesisantagonists.MMPsandTIMPsplayacomplexroleinregulatingangiogenesis.Anunderstandingofthebiochemicalandcellularpathwaysandmechanismsofangiogenesiswillprovideimportantinformationtoallowthecontrolofangiogenesis,e.g.thestimulationofangiogenesisforcoronarycollateralcirculationformation;whiletheinhibitionfortreatingarthritisandcancer.

  • 标签: 新生血管发生 基质金属蛋白酶 作用 胞外基质 胶原酶
  • 简介:ERP is based on the advanced and effective management thoughts and methods. It makes use of new management mode to rebuild old one in one enterprise. The relationship between ERP and the enterprise is supplementary to each other.,3. Embodying the thoughts of pre-planning and controlling during the process  The planning structure in ERP system includes,which indicates that the company’s decision maker plays a special role during the implementation stage. ERP is the system on management which leads and supervises the entire enterprise. It would have not been effective if the CEO has not approved and authorized the system.

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  • 简介:opening to the whole supply chain.Thoughts of ERP system management,achieving the leading position on the market. Applying ERP system into the management of the entire enterprise’s supply chain is the call from the marketing competition in the knowledge economy era.,the process management

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  • 简介:Thetreesinurbanlandscapes,independentofwhethertheyareinurbanforestsorstandalone,canimproveenvironmentquality,enhanceindividualandcommunitywell-being,provideawiderangeofservicestoindividualsandcommunities,andproduceamorehealthfulandcomfortableenvironmentforthevastmajorityofthepopulation.Knowledgeofthepotentialsignificanceoftreesinurbanlandscapesisexpandingrapidlyasresearchcontinuestodocumenttheimportantrolethaturbanforestsandtreescanplayinimprovingthequalityofurbanlife.Theenvironmentalconditionsinurbanlandscapesare,however,verydifferentfromthenaturalconditionsthatthetreespeciesareadaptedto.Thisposesbigchallengestotheurbanforestryinitseffortstocreatehealthyandvaluabletreesinurbanlandscapes.Onlythroughimplementingsomeimportantmeasureswecanensurehighsurvivalrateofsaplingsandwell-beingandlongevityofurbantrees.

  • 标签: 城市景观 城市森林 植树造林 城市绿化 可持续发展 组织领导
  • 简介:六月的第三个星期天是美国的父亲节,但是父亲节是如何起源的呢?节日里有些什么习俗呢?父亲在美国人的心中为什么没有母亲那么伟大呢?请看……

  • 标签: 大学英语 注释 读物 文化背景知识 阅读练习
  • 简介:ApoptosisplaysanessentialroleinTcellbiology.ThymocytesexpressingnonfunctionalorautoreactiveTCRsareeliminatedbyapoptosisduringdevelopment.ApoptosisalsoleadstothedeletionofexpandedeffectorTcellsduringimmuneresponses.Thedysregulationofapoptosisintheimmunesystemresultsinautoimmunity,tumorogenesisandimmunodeficiency.Twomajorpathwaysleadtoapoptosis:theintrinsiccelldeathpathwaycontrolledbyBcl-2familymembersandtheextrinsiccelldeathpathwaycontrolledbydeathreceptorsignaling.Thesetwopathwaysworktogethertoregu

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  • 简介:Traditionally,bonestructureandbonemassareassessedbyobservingtherari-fiedboneonstandardx-rayfilms.However,smallchangesinbonemasscannotbedetectedeffectively.Bythetimelossofbonemasscanbedetectedonthex-ray,thediseaseisalreadyinanadvancestage.Atleast30%ofbonemustbelostbeforeproblemslikeosteoporosiscanbediagnosed.

  • 标签: OSTEOPOROSIS observing assessed IMPLANT FEMORAL fixation