学科分类
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17 个结果
  • 简介:Naturalproductshavegainedpopularityworldwideforpromotinghealthcare,aswellasdiseaseprevention.Alkaloidsareimportantchemicalcompoundsthatserveasarichreservoirfordrugdiscovery.Severalalkaloidsisolatedfromnaturalherbsexhibitantiproliferation,antibacterial,antiviral,insecticidal,andantimetastaticeffectsonvarioustypesofcancersbothinvitroandinvivo.Thispaperfocusesonthenaturally-derivedalkaloidssuchasberberine,matrine,piperine,fritillarine,andrhynchophylline,etc.,andsummarizestheactionmechanismsofthesecompounds.Basedontheinformationintheliteraturethatissummarizedinthispaper,theuseofalkaloidsasdrugsisverypromising,butmoreresearchandclinicaltrialsarenecessarybeforefinalrecommendationsonspecificalkaloidscanbemade.Followingthis,itishopedthatasaresultofthisreview,therewillbeagreaterawarenessoftheexcellentpromisethatnaturalalkaloidsshowforuseinthetherapyofdiseases.

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  • 简介:Cloudmicrophysicalpropertyretrievalsfromtheactivemicrowaveinstrumentonasatelliterequiretheclouddropletsizedistributionobtainedfromaircraftobservationsasaprioridataintheiterationprocedure.Thecloudlognormalsizedistributionsderivedfrom12flightsoverBeijing,China,in2008–09werecharacterizedtoevaluateandimproveregionalCloudSatcloudwatercontentretrievals.Wepresentthedistributionparametersofstratiformclouddroplet(diameter<500μmand<1500μm)anddiscusstheeffectoflargeparticlesondistributionparameterfitting.Basedonthreeretrievalschemeswithdifferentlognormalsizedistributionparameters,theverticaldistributionofcloudliquidandicewatercontentwerederivedandthencomparedwiththeaircraftobservations.Theresultsshowedthattheliquidwatercontent(LWC)retrievalsfromlargeparticlesizedistributionsweremoreconsistentwiththeverticaldistributionofcloudwatercontentprofilesderivedfrominsitudataon25September2006.WethenappliedtwoschemeswithdifferentaprioridataderivedfromflightdatatoCloudSatoverpassesinnorthernChinaduringApril–Octoberin2008and2009.TheCloudSatcloudwaterpath(CWP)retrievalswerecomparedwithModerateResolutionImagingSpectroradiometer(MODIS)liquidwaterpath(LWP)data.TheresultsindicatedthatconsideringaprioridataincludinglargeparticlesizeinformationcansignificantlyimprovetheconsistencybetweentheCloudSatCWPandMODISCWP.Theseresultsstronglysuggestthatitisnecessarytoconsiderparticleswithdiametersgreaterthan50μminCloudSatLWCretrievals.

  • 标签: 飞机观测 反演 物理属性 北京 中分辨率成像光谱仪 MODIS
  • 简介:FragileXsyndromeisthemostcommonformofinheritedmentalretardationaffectingupto1in4000individuals.ThesyndromeisinducedbyamutationintheFMR1gene,causingadeficiencyinitsgeneby-productFMRP.ImpairmentinthenormalfunctioningofFMRPleadstolearningandmemorydeficitsandheightenedsensitivitytosensorystimuli,includingsound(hyperacusis).ThemolecularbasisoffragileXsyndromeisthoroughlyunderstood;however,theneuralmechanismsunderlyinghyperacusishavenotyetbeendetermined.Astheinferiorcolliculus(IC)istheprincipalmidbrainnucleusoftheauditorypathway,thecurrentstudyaddressesthequestionsunderlyingtheneuralmechanismofhyperacusiswithintheICoffragileXmice.AcuteexperimentswereperformedinwhichelectrophysiologicalrecordingsoftheICinFMR1-KOandWTmiceweremeasured.ResultsshowedthatQ-valuesforWTweresignificantlylargerthanthatofFMR-1KOmice,indicatingthatWTmiceexhibitsharpertuningcurvesthanFMR1-KOmice.WealsofoundtheratioofthemonotonicneuronsintheKOmicewasmuchhigherthantheWTmice.TheseresultssuggestthatlackofFMRPintheauditorysystemaffectsthedevelopmentalmaturationandfunctionofstructureswithintheauditorypathway,andinthiscasespecificallytheIC.ThedysfunctionobservedwithintheauditoryneuralpathwayandinparticulartheICmayberelatedtotheincreasedsusceptibilitytosoundasseeninindividualswithfragileXsyndrome.OurstudymayhelponunderstandingthemechanismsofthefragileXsyndromeandhyperacusis.

  • 标签: 下丘神经元 基因突变 点火性能 脆性X综合征 听觉通路 神经机制
  • 简介:Inthepresentwork,themicrostructure,texture,andmechanicalpropertiesofacold-rolledTi-IFsteel,afterannealingatdifferentheatingrates,havebeeninvestigated.Theresultsrevealthatthemeangrainsizeisgraduallyrefinedfrom19.2to16.3μmastheheatingrateincreasesfrom4to50℃/s,butrefinedonlyslightlyatheatingratesofover50℃/s.Therecrystallizationmicrostructurehasastrongtexture,whichisaresultofthesharpeningofthefavorable{111}//ND(normaldirection)texturecomponentsorγ-fiber.Withincreasingheatingrates,thepeakvalueoff(g)ofγ-fiberdecreasesfrom17to9.Theyieldandtensilestrengthsincreasegraduallyastheheatingrateincreasesfrom4to50℃/s,butremainalmostunchangedatheatingratesofmorethan50℃/s.Thetotalelongationanduniformelongationincreasegraduallyastheheatingrateincreasesfrom4to100℃/s,butdecreasesslowlyforheatingrateshigherthan100℃/s.Astheheatingrateincreasesfrom4to100℃/s,theplasticstrainratioofthesteeldecreasesfrom2.8to2.2;however,itincreasesto2.9forheatingratesabove100℃/s.Thestrainhardeningexponentremainsunchangedat0.27inallannealingcycles.

  • 标签: 升温速率 超低碳钢 再结晶 组织与性能 加热速率 均匀延伸率
  • 简介:Themechanismsfortheregulationofsynapticdopamine(DA)includeitsreleasefrompresynapticvesicles,itsinteractionwithpost-synapticandpre-synapticDAreceptors,thereuptakeofDA,viadopaminetransporter(DAT),thediffusionofDAanditsmetabolismbymono-amineoxidase(MAO)andcatechol-O-methyltransferase(COMT).DAcontrolscomplexand

  • 标签: 多巴胺受体 神经再生 甲基化反应 管理 开关 关闭
  • 简介:Acompetitiveenzyme-linkedimmunosorbentassay(ELISA)wasdevelopedtodetermineruscogenin(RUS)byusingthemonoclonalantibody(McAb).ThemonoclonalantibodyagainstRUS,secretedfromtheestablishedhybridomacelllines,wasidentifiedasbeingoftheIgG1isotype.TheMcAbexhibitedhighspecificitytoRUS,showingaveryslightcrossreactivitywithdiosgenin(15.7%),andnocross-reactivitytosarsasapogenin,diammoniumglycyrrhizinate,oleanolicacidandnotoginsenosideR1.TheestablishedELISA,atanIC50valueof157.55ng.mL-1andadetectionlimit(IC20)of20.57ng.mL-1,wascomparedwithHPLCanalyses,andagoodcorrelationbetweenELISAandHPLC-ELSDanalysesofRUSintheextractofRadixOphiopogoniswasobtained.TheexperimentaldataindicatedthattheELISAmethodexhibitsmoreadvantagesoverHPLC-ELSD,suchaslowdetectionlimit,highspecificity,lowbackground,andnorequirementforsamplepre-treatment,andismoresuitableforthedeterminationofnaturalcomponentsinChinesetraditionalmedicinesandinbiologicalsamplesforpharmacokineticstudies.

  • 标签: ELISA 中国传统 鲁斯可皂苷元
  • 简介:我们在奇塔贡·希尔道在Khagarachari山区域的Aatmile从二个代表性的地点收集了土壤样品。这些地点之一在转移耕作和其它下面是邻近的13年的旧柚木种植园。两个地点在有寓言土壤的地文学的状况和一样的方面打的一样,它使我们能测量在土壤上转移耕作的效果微植物群。我们学习了土壤物理化学的性质和土壤微生物的生物化学、生物的性质。象真菌和细菌的人口一样的潮湿和有机物内容,两个在表面和表面下的土壤,显著地(p0.001)在不在转移耕作下面与土壤相比转移栽培土壤更低,即柚木种植园地点。在表面(010厘米)的最丰富的细菌并且表面下(1020厘米)分别地,当时,在转移耕作下面的土壤是Pseudomonasdiminuta和Shigella在柚木种植园的相应土壤层,占优势的微生物是杆菌firmus(010厘米)和Xanthomonas(1020厘米)。因为,微生物引起的人口差别不能被土壤质地差别解释组织上从二个地点的土壤的类似但是能在在转移耕作下面的土壤与显著地更低的潮湿和有机物内容有关。

  • 标签: 土壤类型 生物化学 刀耕火种 微生物 孟加拉国 抽搐
  • 简介:Ba0.85Ca0.15Ti0.9Zr0.1O3(BCTZ)lead-freepiezoelectricceramicsco-dopedwithCeO2(x=0.1wt.%,0.2wt.%,0.3wt.%,0.4wt.%,0.5wt.%)andLi2CO3(0.6wt.%)werepreparedbyconventionalsolid-statereactionmethod.InfluenceofCeO2dopingamountonthepiezoelectricproperties,dielectricproperties,phasecompositionandmicrostructureofpreparedBCTZlead-freepiezoelectricceramicsdopedwithLi2CO3wereinvestigatedbyX-raydiffraction(XRD)andscanningelectronmicroscopy(SEM)andotheranalyticalmethods.TheresultsshowedthatthesinteredtemperatureofBCTZlead-freepiezoelectricceramicsdopedwithCeO2decreasedgreatlywhenLi2CO3dopingamountwas0.6wt.%;apureperovskitestructureofBCTZlead-freepiezoelectricceramicsco-dopedwithLi2CO3andCeO2andsinteredat1050°Ccouldalsobeobtained.Thepiezoelectricconstant(d33),therelativepermittivity(εr)andtheplanarelectromechanicalcouplingfactor(kp)ofBCTZceramicsdopedwithLi2CO3increasedfirstlyandthendecreased,thedielectricloss(tanδ)decreasedfirstlyandthenincreasedanddecreasedatlastwhenCeO2dopingamountincreased.TheinfluenceofCeO2dopingonthepropertiesofBCTZlead-freepiezoelectricceramicsdopedwithLi2CO3werecausedby'softeffect'and'hardeffect'piezoelectricadditiveandcausinglatticedistortion.WhenCeO2dopingamount(x)was0.2wt.%,theBCTZceramicsdopedwithLi2CO3(0.6wt.%)andsinteredat1050°Cpossessedthebestpiezoelectricpropertyanddielectricpropertywithd33of436pC/N,kpof48.3%,εrof3650,tanδof1.5%.

  • 标签: 无铅压电陶瓷 陶瓷性能 低温烧结 掺杂量 氧化铈 扫描电子显微镜
  • 简介:biomagnesium合金被认为由于它的好机械相容性,生物相容性,生物安全和可被细菌破坏的特征是最潜在的可被细菌破坏的金属材料之一。然而,在生理的环境和低机械性质的高降级率的二个主要问题阻止biomagnesium合金的发展。在现在的工作,Mg-Zn-Y-Nd合金的样品被周期的挤出压缩(CEC)和相等的隧道准备尖紧迫(ECAP)。微观结构,合金的机械性质和它在模仿的身体液体(SBF)的腐蚀行为被评估。结果表明那Mg-Zn-Y-Nd合金与测微计尺寸和缩放nano的秒阶段的同类的分发由equiaxial罚款谷物结构组成,它被动态再结晶在ECAP和CEC期间引起。合金的腐蚀抵抗被改进。张力并且腐蚀抵抗被改进,特别处理合金展览制服腐蚀表演和减少的腐蚀评价。这将作为脉管的stent申请为Mg-Zn-Y-Nd合金提供理论地面。

  • 标签: 耐腐蚀性 力学性能 钕合金 血管支架 模拟体液 腐蚀行为
  • 简介:二新-hydroxy氨基的联合酸的secoiridoids,命名serinosecologanin(1)和threoninosecologanin(2),从忍冬装饰用的梨树的花芽的一篇水的摘录被孤立。他们包括绝对配置的不平常的结构被分光镜的数据分析决定,并且从共同发生的secologanin(3)和secologanic酸(4)由semisynthesis证实了。从曲霉属菌尼日尔从杏仁和hesperidinase对-glucosidase加重1和2项展出抵抗活动,他们也在激活血小板的因素与抑制率导致的老鼠polymorphonuclear白血球对glucuronidase的版本显示出活动(34.9 ;± ;3.1)%并且(53.6 ;± ;2.6)%分别地。

  • 标签: 羟基氨基酸 生物活性 结构鉴定 半合成 分离 花蕾
  • 简介:Wereportanovelapproachtoobtainingaclassicalblue-greenexcitableCaS:Eu2+phosphorwithdesiredredemissionbymicrowave(MW)firingprocedureintheabsenceofaddingelementalsulphur.ThedisturbingeffectofMWelectromagneticfieldondecompositionofCaSO4intoCaSactivatedbyeuropiumisdistinctlyobservedtogivepurehostphasewithoutaddinganyelementalsulphurandcarbon.ThehostphaseevolutionisobservedtobehighlydependentonthevariationofappliedMWpowerfromX-raydiffraction(XRD)patternsandthecorrespondingphotoluminescence(PL),andamaximumPLintensityat1100WofMWpowerisacquiredfortheobtainedpurerhostphase.Thenon-thermalandnon-equilibriumeffectsbyMWarerevealedtocorrelatewiththeinteractionbetweenpolarstructureofthehostandappliedelectromagneticfield.Theresultsdemonstrateanoptionalproceduretopreparethisred-emittingphosphorinaneffective,environment-friendlyandscalableapproachforphosphorproductionintheapplicationofbio-illuminationforplantcultivationandartificialphotosynthesis.

  • 标签: 光致发光性质 红光发射 微波促进 荧光粉 硫酸钙 CAS
  • 简介:AseriesofCe0.5Fe0.30Zr0.20O2catalystswerepreparedbydifferentmethods(co-precipitationsmethod,citricacidsol-gelmethod,impregnationmethod,physicalmixedmethod,andhydrothermalmethod)andcharacterizedbyX-raydiffraction(XRD),Ramanspectroscopy,Brunauer-Emmett-Teller(BET)andH2-TPRmeasurements.Potentialofthecatalystsinthesootoxidationwasevaluatedinatemperature-programmedoxidation(TPO)apparatus.TheresultsshowedthatalltheFe3+andZr4+wereincorporatedintocerialatticetoformapureCe-Fe-Zr-Osolidsolutionfortheco-precipitationsample,buttwokindsofFephasesexistedintheCe-Fe-Zr-Ocatalystspreparedbyothermethods:Fe3+incorporatedintoCeO2latticeanddispersedFe2O3clusters.ThefreeFe2O3clusterscouldimprovetheactivityofcatalystsforsootoxidationcomparingwiththepureCe-Fe-Zr-OsolidsolutionowingtothesynergeticeffectbetweenfreeFe2O3andsurfaceoxygenvacancies.Inaddition,theactivityofcatalystsstronglyreliedonthesurfacereducibilityoffreeFe2O3particles.HoldingbothabundantfreeFe2O3particlesandhighoxygenvacancyconcentration,thehydrothermalCe0.5Fe0.3Zr0.2O2catalystpresentedthelowestTi(251°C,ignitiontemperatureofsootoxidation)andTm(310°C,maximumoxidationratetemperature)forsootcombustion(withtight-contactbetweensootandcatalysts)amongthefivesamples.Evenafteragingat800°Cfor10h,theTiandTmwerestillrelativelylow,at273and361°C,respectively,indicatinghighcatalyticstability.

  • 标签: 氧化物催化剂 制备方法 氧化铈 碳烟氧化 氧化铁 催化性能