简介:AconstitutiveequationtheoryofOldroydfluidBtype,i.e.theco-rotationalderivativetype,isdevelopedfortheanisotropic-viscoelasticfluidofliquidcrystalline(LC)polymer.Analyzingtheinfluenceoftheorientationalmotiononthematerialbehaviorandneglectingtheinfluence,theconstitutiveequationisappliedtoasimplecaseforthehydrodynamicmotionwhentheorientationalcontributionisneglectedinitandtheanisotropicrelaxation,retardationtimesandanisotropicviscositiesareintroducedtodescribethemacroscopicbehavioroftheanisotropicLCpolymerfluid.UsingtheequationfortheshearflowofLCpolymerfluid,theanalyticalexpressionsoftheapparentviscosityandthenormalstressdifferencesaregivenwhichareinagoodagreementwiththeexperimentalresultsofBaeketal.Forthefiberspinningflowofthefluid,theanalyticalexpressionoftheextensionalviscosityisgiven.
简介:Toinvestigatewhetherestradiol(E2)playsaroleincell-contact-dependentregulatorymechanismofTcellactivation,westudiedtheroleofE2inregulatinggenetranscriptionofCTLA-4,ICOS,B7-1,B7-2andB7hinvitro.ThespleniccellsofnormalfemaleBALB/cmicewereactivatedbyConA.ThenthecellswereculturedwithE2(100pg/mlor50ng/ml)for24hor48h,respectively.ThecellproliferationwasmeasuredbyMTTassayandtheexpressionoftheco-stimulatorymoleculesmRNAwasexaminedbyRT-PCRanalysis.WefoundthatE2(100pg/ml,physiologicallevel)stimulatedtheactivatedspleencellsproliferation;inhibitedCTLA-4,ICOS,TGF-βandIL-10genetranscription;promotedB7-1andB7-2genetranscription.E2(50ng/ml,pregnantlevel)inhibitedtheproliferationoftheactivatedspleniccells;promotedCTLA-4,B7-1,IL-10butinhibitedB7-2andTGF-βgenetranscription.Therefore,weconcludethattheeffectsofE2onTcellactivationarepartiallythroughitsregulationontheco-stimulatorymolecules.Theco-stimulatorymoleculesarecrucialcomponentsofthecell-contactdependentregulatorymechanism,andE2mayregulateTcellactivationbythismechanism.
简介:Fourpolymer-supportedFe-Cotetrametallicclustershavebeenpreparedbyionexchangeandligandexchange.TheirstructureswerecharacterizedbyIR,UV/visiblediffusereflectancespectraandelementalanalysis,andbyanalogywiththereferenceclusterPhCH2NMe3FeCo3(CO)2.Thefourheterogenousclusterswereefficientcatalystsinthehydroformylationof1-hexene,turnovernumbersamountedto823—924withtheyieldof83.2—92.4%heptylaldehydesandratiosofnormalaldehydetoiso-aldehydeof1.2—1.6,theyarefacilitatedformingthenormalaldehydeincomparisonwiththehomogeneousanalogue.Forthepolymer-supportedclusterspreparedbyionexchange,thepolymer-cationpartshadnoobviouseffectontheactivityoftheclusteranion.Thepolymer-phosphinesubstitutedclusterpreparedbyligandexchangewasmorestablethantheclusterspreparedbyionexchange.
简介:Takingpublictransitfacilities(PTFs)isthemajortransportstyleinHongKong.Humanexposuretoindoorairpollutantsmaycauseadversehealtheffectstothepassengers.Exposureassessmentonairpollutantsisimportantforthecontrolofhumandiseasescausedbyindoorairpollution.Inthispaper,theindoorPM10,COandCO2levelsinvariousPTFs,suchaspublicbus,subway,railwayandferryinHongKong,weremea-sured.CombiningwiththetimebudgetsurveyofHongKongpopulation,thehumanexposureswerecalculatedthroughMonte-Carlosimulation.
简介:ThecrystalstructureofDi-nitratobis(ethylcaprolactam)uranyl(Ⅱ)UO2[CH2(CH2)4CONC2H5]2(NO3)2wasestablishedbyasingle-crystalX-raydiffractionstudy.Itistriclinie,spacegroupP1,witha=7.171(2),b=8.655(3),c=10.182(5)A,α=78.27(3),β=70.63(3),γ=81.76(3)°,V=581.7(4)A3,Z=l,Dc=1.94g.cm-3.FinalRvalueis0.0218.Theresultrevealsthaturanylioniscoordinatedtosixoxygenatoms,twoofthemarefromtwocarbonylgroupsofethylcaprolactamandtheotherfourarefromtwonitrategroups.