简介:Theinvestigationofelectrochromiceffectofcorona-polednonlinearopticalpolymerfilmsisaneffectivemethodfortheestimationofpolinglevelandtheselectionofpolingconditions.ThepolingelectricfieldEpandorientationalorderparameterΦ,whicharetheimportantparameterstopredictd33ofpoledfilms,canbecalculatedbyasimpleoperationfromthenumberofredshiftofchargetransferabsorptionband.Thecalculatedresultsareingoodagreementwiththeexperimentaldata.
简介:Wereportonasystematicexperimentalstudyonthefluorescencespectraproducedfromafemtosecondlaserfilamentinairunderahighelectricfield.Theelectricfieldalonewasstrongenoughtocreatecoronadischarge(CD).Fluorescencespectrafromneutralandionicairmoleculesweremeasuredandcomparedwithpurehigh-voltageCDandpurelaserfilamentation(FIL).Amongthem,highelectricfieldassistedlaserFILproducednitrogenfluorescencemoreefficientlythaneitherpureCDorpureFILprocesses.Thenonlinearenhancementoffluorescencefromtheinteractionofthelaserfilamentandcoronadischargingelectricfieldresultedinamoreefficientionizationalongthelaserfilamentzone,whichwasconfirmedbythespectroscopicmeasurementofbothionization-inducedfluorescenceandplasma-scattered800nmlaserpulses.Thisisbelievedtobethekeyprecursorprocessforfilament-guideddischarge.
简介:ThepaperpresentsthebasicmodelforthetransmissiondynamicsofWestNilevirus(WNV).Themodel,whichconsistsofsevenmutually-exclusivecompartmentsrepresentingthebirdsandvectordynamics,hasalocally-asymptoticallystablediseasefreeequilibriumwhenevertheassociatedreproductionnumber(R0)islessthanunity.Asrevealin[3,20],theanalysesofthemodelshowtheexistenceofthephenomenonofbackwardbifurcation(wherethestabledisease-freeequilibriumofthemodelco-existswithastableendemicequilibriumwhenthereproductionnumberofthediseaseislessthanunity).Itisshown,thatthebackwardbifurcationphenomenoncanberemovedbysubstitutingtheassociatedstandardincidencefunctionwithamassactionincidence.Analysisofthereproductionnumberofthemodelshowsthat,thediseasewillpersist,wheneverR0>1,andincreaseinthelengthofincubationperiodcanhelpreduceWNVburdeninthecommunityifacertainthresholdquantities,denotedby△band△varenegative.Ontheotherhand,increasingthelengthoftheincubationperiodincreasesdiseaseburdenif△b>0and△v>0.Furthermore,itisshownthataddingtimedelaytothecorrespondingautonomousmodelwithstandardincidence(consideredin[2])doesnotalterthequalitativedynamicsoftheautonomoussystem(withrespecttotheeliminationorpersistenceofthedisease).
简介:Thestructureandkineticsofthecomplexformedbyhyaluronicacid(HA)andpoly(L-lysine)(PLL)werestudiedbytimeresolvedlaserlightscattering,TEM,andAFM.BecauseHAhasahydrophilicbackbone,thecomplexesformedbyHAandPLLaredifferentfromthoseformedbyoppositelychargedpolyelectrolytesbothhavinghydrophobicbackbones.Insteadofformingstrongaggregatesandevenprecipitates,thecomplexinthepresenceofexcessHAisstableinthestudiedtimeperiod.Moreimportantly,thecomplexspontaneouslyformscore-coronastructurebytherearrangementofHAchains.ThecoreiscomposedofcomplexrichofPLLandthecoronaismainlyHA.FurtheranalysisshowsthatthehydrogenbondformedbyHAcreatesabarrierhinderingthefurtherrelaxationofHAchains.Theautomaticformationofcore-coronastructurebyPLL/HAishelpfulnotonlytounderstandtherelaxationofpolyelectrolyteincomplex,butalsotodevelopdrugcarrierswithdesirableproperties.
简介:某些疾病被知道引起变化在物理并且房间的biomechanical性质。这些在其它之中包括癌症,疟疾,和镰刀房间贫血症。典型地,如此的物理性质变化能导致房间僵硬的几褶层增加或减少,它是重要的并且能导致严重病理和最终的灾难的故障身体功能。当有时开发了生物化学、生物的试金检测疾病的发作或存在,总是有需要开发更快速、精确、敏感的方法检测并且诊断疾病。Biomechanical性质变化能起一个重要作用在这方面。因此,对疾病biomechanics的研究不能仅仅给我们位于疾病前进下面的机制的深入的知识,但是能也为察觉和诊断用作一个强大的工具。这篇文章提供一些卓见进机会因为在疾病的发作或前进期间在细胞的机械性质换掉怎么重要,能为察觉和诊断作为有用工具被利用。我们将也展示已经被开发了执行如此的察觉和诊断的几种技术。
简介:SYNTHESISANDANTI-HUMANIMMUNODEFICIENCYVIRUS-1(HIV-1)ACTIVITYOF9-(2-PHOSPHONYLMETHOXYETHYL)ADENINE(1)ANDITSREGIOISOMER3-(2-PHO...