简介:AbstractBackground:In recent years, norepinephrine has attracted increasing attention for the management of maternal hypotension during elective cesarean section with spinal anesthesia. Intermittent bolus is a widely used administration paradigm for vasopressors in obstetric anesthesia in China. Thus, in this randomized, double-blinded study, we compared the efficacy and safety of equivalent bolus norepinephrine and phenylephrine for rescuing maternal post-spinal hypotension.Methods:In a tertiary women’s hospital in Nanjing, China, 102 women were allocated with computer derived randomized number to receive prophylactic 8 μg norepinephrine (group N; n = 52) or 100 μg phenylephrine (group P; n = 50) immediately post-spinal anesthesia, followed by an extra bolus of the same dosage until delivery whenever maternal systolic blood pressure became lower than 80% of the baseline. Our primary outcome was standardized maternal cardiac output (CO) reading from spinal anesthesia until delivery analyzed by a two-step method. Other hemodynamic parameters related to vasopressor efficacy and safety were considered as secondary outcomes. Maternal side effects and neonatal outcomes were collected as well.Results:Compared to group P, women in group N had a higher CO (standardized CO 5.8 ± 0.9 vs. 5.3 ± 1.0 L/min, t = 2.37, P = 0.02) and stroke volume (SV, standardized SV 73.6 ± 17.2 vs. 60.0 ± 13.3 mL, t = 4.52, P < 0.001), and a lower total peripheral resistance (875 ± 174 vs. 996 ± 182 dyne·s/cm5, t = 3.44, P < 0.001). Furthermore, the incidence of bradycardia was lower in group N than in group P (2% vs. 14%, P= 0.023), along with an overall higher standardized heart rate (78.8 ± 11.6 vs. 75.0 ± 7.3 beats/min, P = 0.049). Other hemodynamics, as well as maternal side effects and neonatal outcomes, were similar in two groups (P > 0.05).Conclusions:Compared to equivalent phenylephrine, intermittent bolus norepinephrine provides a greater CO for management of maternal hypotension during elective cesarean section with spinal anesthesia; however, no obvious maternal or neonatal clinical advantages were observed for norepinephrine.
简介:PlasmonicresonancewithFanolineshapehasattractedagreatdealofrecentinterest.Herewedesignanewstructurewithadimergratinguponagoldfilmseparatedbyalayerofsilicaspacer,whichhastworesonantmodescorrespondingtothedimer’slocalizedsurfaceplasmonresonanceandthesurfaceplasmonresonanceexcitedbythedimergrating.Thisstructurehasthreeadvantagesfornear-infrareddetectioninwater.First,itprovidestworesonantmodestoenhancetheexcitationandscatteredsignalsofsurface-enhancedRamanscattering.Second,couplingofthesetwomodesresultsinaFanoresonance,providingahigherelectricfieldenhancement.Finally,thedimerprovidesmoreflexibletunabilitycomparedtoasinglediskstructure.
简介:Thispapergeneralizesthesingle-shellKidder'sself-similarsolutiontothedouble-shellonewithadiscontinuityindensityacrosstheinterface.AnisentropicimplosionmodelisconstructedtostudytheRayleigh-Taylorinstabilityfortheimplosioncompression,AGodunov-typemethodintheLagrangiancoordinatesisusedtocomputetheone-dimensionalEulerequationwiththeinitialandboundaryconditionsforthedouble-shellKidder'sself-similarsolutioninsphericalgeometry.Numericalresultsareobtainedtovalidatethedouble-shellimplosionmodel.Byprogrammingandusingthelinearperturbationcodes,alinearstabilityanalysisontheRayleigh-Taylorinstabilityforthedouble-shellisentropicimplosionmodelisperformed.Itisfoundthat,whentheinitialperturbationisconcentratedmuchclosertotheinterfaceofthetwoshells,orwhenthesphericalwavenumberbecomesmuchsmaller,themodalradiusoftheinterfacegrowsmuchfaster,i.e.,moreunstable.Inaddition,fromthespatialpointofviewforthecompressibilityeffectontheperturbationevolution,thecompressibilityoftheoutershellhasadestabilizationeffectontheRayleigh-Taylorinstability,whilethecompressibilityoftheinnershellhasastabilizationeffect.
简介:BasedonGlobalOceanDataAssimilationSystem(GODAS)andNCEPreanalysisdata,atmosphericandoceanicprocessespossiblyresponsiblefortheonsetofthe2011/12LaNiaevent,whichfollowedthe2010/11LaNiaeven—referredtoasa'doubledip'LaNia—areinvestigated.Thekeymechanismsinvolvedinactivatingthe2011/12LaNiaareillustratedbythesedatasets.ResultsshowthatneutralconditionswerealreadyevidentintheequatorialeasternPacificduringthedecayingphaseofthe2010/11LaNia.However,isothermalanalysesshowobviouslycoldwaterstillpersistingatthesurfaceandatsubsurfacedepthsinoff-equatorialregionsthroughoutearly2011,beingmostpronouncedinthetropicalSouthPacific.ThenegativeSSTanomaliesinthetropicalSouthPacificactedtostrengthenasouthernwindacrosstheequator.ThesubsurfacecoldwaterinthetropicalSouthPacificthenspreadnorthwardandbrokeintotheequatorialregionatthethermoclinedepth.Thisincursionprocessofoff-equatorialsubsurfacecoldwatersuccessfullyinterruptedtheeasternpropagationofwarmwateralongtheequator,whichhadpreviouslyaccumulatedatsubsurfacedepthsinthewarmpoolduringthe2010/11LaNiaevent.Furthermore,theincursionprocessstrengthenedasaresultoftheoff-equatorialeffects,mostlyinthetropicalSouthPacific.ThenegativeSSTanomaliesthenreappearedinthecentralbasininsummer2011,andactedtotriggerlocalcoupledair–seainteractionstoproduceatmospheric–oceanicanomaliesthatdevelopedandevolvedwiththesecondcoolinginthefallof2011.
简介:Theconservationlawsforthe(1+2)-dimensionalZakharov–Kuznetsovmodifiedequalwidth(ZK-MEW)equationwithpowerlawnonlinearityareconstructedbyusingNoether’sapproachthroughaninterestingmethodofincreasingtheorderofthisequation.Withtheaidofanobtainedconservationlaw,thegeneralizeddoublereductiontheoremisappliedtothisequation.ItcanbeshownthatthereducedequationisasecondordernonlinearODE.Finally,someexactsolutionsforaparticularcaseofthisequationareobtainedaftersolvingthereducedequation.
简介:Wereportonanall-fiberoscillatorfollowedbyanall-fiberamplifiertoproduceasshortas382fslaserpulseswithupto0.9Waveragepower.Theoscillatorisanall-normal-dispersionall-fiberdissipativesolitonlaseroperatingat1030nm,andoperatingindissipativesolitonmode.Theamplifierstageismainlybasedonadouble-cladding20μmradiusytterbium-dopedfiberpumpedbyanupto2.5WCWlasersource.Theoptical-to-opticalconversionamplifierefficiencyisaround40%.Toourknowledge,thisisthefirstreportofanall-fibermode-lockedfiberlaseroscillatoramplifiedbyanall-fiberamplifier.
简介:阴极材料李[CoxNiyMn1?x?y]为锂的O2第二等的电池被一条新线路作为一位先锋用分层的双氢氧化物(LDH)准备了。结果有-NaFeO2结构的分层的阶段在菱形的系统结晶,与有到0.47nm的夹层间距结束的空格组R-3m。X光检查光电子光谱学(XPS)被用来测量公司,Ni和Mn的氧化状态。在结构和李的电气化学的性质上改变Co/Ni/Mn比率的效果[CoxNiyMn1?x?y]O2被X光检查衍射和电气化学的测试调查了。产品表明了相当稳定的骑车行为,与为有Co/Ni/Mn=1/1/1的分层的材料的118mAh/g的一个可逆能力。
简介:Indouble-pulselaser-inducedbreakdownspectroscopy(DP-LIBS),thecollinearfemtoseconddouble-pulselaserconfigurationisexperimentallyinvestigatedwithdifferentinitialsampletemperaturesusingaTi:sapphirelaser.Theglasssampleisablatedtoproducetheplasmaspectroscopy.Duringtheexperiment,thedetectedspectrallinesincludetwoNa(I)lines(589.0nmand589.6nm)andoneCa(I)lineatthewavelengthof585.7nm.Theemissionlinesaremeasuredatroomtemperature(22°C)andthreehigherinitialsampletemperatures(Ts=100°C,200°C,and250°C).Theinter-pulsedelaytimerangesfrom-250psto250ps.Theinter-pulsedelaytimeandthesampletemperaturestronglyinfluencethespectralintensity,andthespectralintensitycanbesignificantlyenhancedbyincreasingthesampletemperatureandselectingtheoptimizedinter-pulsetime.Forthesameinter-pulsetimeof0ps(single-pulseLIBS),theenhancementratioisapproximately2.5atTs=200°CcomparedwiththatobtainedatTs=22°C.Forthesameinter-pulsetimeof150ps,theenhancementratiocanbeupto4atTs=200°CcomparedwiththatobtainedatTs=22°C.Thecombinedenhancementeffectsofthedifferentinitialsampletemperaturesandthedouble-pulseconfigurationinfemtosecondLIBSaremuchstrongerthanthatofthedifferentinitialsampletemperaturesorthedouble-pulseconfigurationonly.
简介:TheenergybanddiagramandchargedistributionoftheunintentionaldopedAIGaN/GaN/AIGaN/GaNdoubleheterostructurewereobtainedbyself-consistentPoissonSchroedingercalculations.Theseverebandtiltingandhightwo-dimensionalelectrongas(2DEG)densitymainlyattributetothelargeinternalpolarizationintensity,whichisc/osetoalinearfunctionorAlcomposition.TheinfluenceorAlcompositionisinvestigated.Theresultsshowthatbandtiltingenlargesand2DEGgainswithAIcomposition,andtwo-dimensionalholegasoccurswhenAIcompositionreachesacertainextent.TheinfluenceorAlcompositionandtwo-dimensionalholegas(2DHG)ondevicesisdiscussed.