学科分类
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77 个结果
  • 简介:cJUNNH2-terminalkinase(JNK)hasbeenreportedtoplayimportantrolesinregulatingthecellularapoptosisandautophagy.However,accuratemechanismandhowthebalanceoftheseactivitiesdeterminesthecellularradiosensitivityremainunclear.

  • 标签: FUNCTION Mediating AUTOPHAGY
  • 简介:Perovskite-typeLa1-xCexMnO3(x=0-10%)catalystswerepreparedbyflamespraypyrolysisandtheiractivitiesduringthecatalyticoxidationofbenzenewereexaminedoverthetemperaturerangeof100-450℃.ThestructuralpropertiesandreducibilityofthesematerialswerealsocharacterizedbyX-raydiffraction(XRD),N2adsorption/desorption,H2temperature-programmedreduction(H2-TPR)andX-rayphotoelectronspectroscopy(XPS).TheincorporationofCewasfoundtoimprovethebenzeneoxidationactivity,andtheperovskiteinwhichxwas0.1exhibitedthehighestactivity.Phasecompositionandsurfaceelementalanalysesindicatedthatnon-stoichiometriccompoundswerepresent.TheincorporationofCehadanegligibleeffectonthespecificsurfaceareaoftheperovskitesandhencethisfactorhaslittleimpactonthecatalyticactivity.IntroductionofCe44+resultedinmodificationofthechemicalstatesofbothB-siteionsandoxygenspeciesandfacilitatedthereducibilityoftheperovskite.ThesurfaceMn4+/Mn3+ratiowasincreasedasaresultofCe4+substitution,whileadecreaseinthesurface-adsorbedO/latticeO(Oads/Olatt)ratiowasobserved.Therelationshipbetweenthesurfaceelementalratiosandcatalyticactivitywasestablishedtoallowabetterunderstandingoftheprocessbywhichbenzeneisoxidizedoverperovskites.

  • 标签: 钙钛矿型 氧化铈 催化剂 掺入 火焰 X射线光电子能谱
  • 简介:Nanostructuredtransitionmetaloxidesarepromisingalternativeanodesforlithiumionbatteries.Li-ionstorageperformanceisexpectedtoimproveifhighpackingdensityenergyparticlesareavailable.Herein,Mn2O3microsphereswithaca.18μmdiameterandatappeddensityof1.33g/cm3weresynthesizedbyafacilesolvothermal-thermalcoversionroute.SphericalMnCO3precursorswereobtainedthroughsolvothermaltreatmentandtheydecomposedandconvertedintoMn2O3microspheresatanannealingtemperatureof700C.TheMn2O3microspheresconsistedofMn2O3nanoparticleswithanaverage40nmdiameter.TheseporousMn2O3microspheresallowgoodelectrolytepenetrationandprovideanionbufferreservoirtoensureaconstantelectrolytesupply.TheMn2O3microsphereshavereversiblecapacitiesof590and320mAh/gat50and400mA/g,respectively.Wethusreportanefficientrouteforthefabricationofenergyparticlesforadvancedenergystorage.

  • 标签: MN2O3 锂离子电池 溶剂热合成 负极材料 微球 过渡金属氧化物
  • 简介:TodepictthedetailsthatCHOP(C/EBPhomologousprotein)regulatesautophagyandapoptosisinbreastcancercells,theexpressionofCHOPwasinhibitedbytransfectionwithsiRNAsequence.AsshowninFig.1,radiati-Fig.1CHOPinhibitionbysiRNAatmRNAandproteinlevelsafterradiation.onelicitedahigherexpressionofCHOPintheNCgroupcomparedwithcontrol.However,thishigherexpressionwassignificantlyinhibitedinthesiRNAgroup.

  • 标签: BREAST Cancer Cells
  • 简介:AgraphGiscalledchromatic-choosableifitschoicenumberisequaltoitschromaticnumber,namelych(G)=χ(G).Ohba’sconjecturestatesthateverygraphGwith2χ(G)+1orfewerverticesischromaticchoosable.ItisclearthatOhba’sconjectureistrueifandonlyifitistrueforcompletemultipartitegraphs.Recently,Kostochka,StiebitzandWoodallshowedthatOhba’sconjectureholdsforcompletemultipartitegraphswithpartitesizeatmostfive.Butthecompletemultipartitegraphswithnorestrictionontheirpartitesize,forwhichOhba’sconjecturehasbeenverifiedarenothingmorethanthegraphsKt+3,2*(k-t-1),1*tbyEnotomoetal.,andKt+2,3,2*(k-t-2),1*tfort≤4byShenetal..Inthispaper,usingtheconceptoff-choosable(orL0-size-choosable)ofgraphs,weshowthatOhba’sconjectureisalsotrueforthegraphsKt+2,3,2*(k-t-2),1*twhent≥5.Thus,Ohba’sconjectureistrueforgraphsKt+2,3,2*(k-t-2),1*tforallintegerst≥1.

  • 标签: 猜想 完全多部图 可选择 时间 KT 色数
  • 简介:Thispaperreportsonthelongevityofglycerol-dry(CO2)reformingoverthelanthanum(La)promotedNi/Al2O3catalysts.TheXRDresultsshowedthattheNiparticlewaswell-dispersedinthepresenceofLapromoter.Inaddition,viatheNH3-TPDanalysis,itwasfoundthattheLapromoterhasreducedtheacidityofNicatalystwhichmayhaveexplainedthemitigationofcarbonlaydown.Itwasdeterminedthatthe3.0wt%La-promotedNi/Al2O3catalystpossessedthelargestBETspecificsurfaceareaof97m2g-1.Consequently,ityieldedthebestcatalyticlongevityperformancewithconversionattainedmorethan90%,evenafter72hofreactionduration.Significantly,itcanbeconfirmedthatthepresenceofCO2duringtheglyceroldryreformingwasessentialinreducingcarbondeposition,mostlikelyviagasificationpathway.Thishasensuredastabilityofcatalyticactivityforalongreactionperiod(72h).

  • 标签: 镍催化剂 Al2O3 CO2 甘油 重整 长寿
  • 简介:Thenatureofresistivetransitionofhigh-qualitycrystallinethinfilmsofYBa2Cu3O7-δhasbeenstudiedundermagneticfields(H)appliedalongthecdirectionoverawiderangeofdopedholes,p,intheCuO2planes.Thefield-andtemperature-dependentin-planeresistivity,ρab(T,H),hasbeenanalyzedwithinthethermallyassistedflux-flow(TAFF)formalism.Thefluxactivationenergy,U(T,H),hasbeenextractedfromthisanalysis.Thelow-Tpartoftheρab(T,H)datacanbedescribedbyanactivationenergyhavingthefunctionalformofU(T,H)=(1-t)m(H-0/H)β,wheret=T/Tc(reducedtemperature),andH0isafieldscalethatprimarilydeterminesthemagnitudeofU(T,H).Thetemperatureexponent,m,showsasystematicvariationwithp,whereasthefieldexponent,β,isinsensitivetothepvaluesandisclosetounity.TheH0,ontheotherhand,changesrapidlyaspisvaried.U(T,H)islinkedtothepinningpotentialandconsequentlyonthesuperconductingcondensationenergy.Sincethenormalstatepseudogapdirectlyaffectssuperconductingcondensationenergy,aclearcorrespondencebetweenH0andthePGenergyscale,εg,isfound.Possibleimplicationsoftheseresultsarediscussed.

  • 标签: 电阻转变 涡动力学 薄膜 赝能隙 YBA2CU3O7 跃迁
  • 简介:BecauseERstressisoneofthesignalingpathwaysinvolvedintheregulationofautophagy,wehypothesizedthatERstressmightalsoplayanimportantroleinradiation-inducedautophagy.SHG44andHeLacellswereirradiatedwithX-raysandcarbonionsof30and75keV/mat2Gy.TheexpressionlevelsofBip,amajorindicatorofUPR,at4and24hpost-irradiationareshowninFig.1(a)and(b)forSHG44andHeLacells,respectively.

  • 标签: PHOSPHORYLATION Tumor Cells
  • 简介:Theeffectsofcarbon-ionirradiationoncancercelltelomerefunctionhavenotbeencomprehensivelystudied[1].Ourpreviousreportshowedthatcancercellswithtelomeredysfunctionweremoresensitivetocarbon-ionirradiation,butthemechanismthatlinktelomeredysfunctionandcancercellinactivationhasnotbeeninvestigated.

  • 标签: Telomere-mitochondrion LINK Contributed
  • 简介:Onenovelorganic-inorganichybridsupramolecularassemblies|(NDPA)(18-crown-6)]2+(DMA)+·3ClO4-(1),hasbeensuccessfullyconstructedthroughtheprominentstrategiesofcrystalengineering(NDPA=N,N-dimethyI-1,4-phenylenediamine,DMA=dimethylamine),andcharacterizedbyIR,powderXRDandsinglecrystalX-raydiffraction.Inthestructure,thesupramolecularorganiccationsandinorganicClO4-anionsarearrangedalternatelyandlinkedbyN-O…Hhydrogenbonds.ItisworthytonotethattheClO4-arelinkedtoformone-dimensionalinorganicchainthroughstrongNH…Ohydrogenbondsalongb-axis.Thereisnodistinctdielectricanomalyinthetemperaturedependentandfrequency-dependentdielectricconstantcurves,suggestingthatnophasetransitionexistswithinthemeasuredtemperaturerange(120-420K).Therelativedisplacementofcationsandanions,theturnedpolarizationofmolecularelectricmomentandmacrocyclicmoleculerotatorarethemainfactorstodeterminethetrendofdielectricconstant.

  • 标签: 超分子组装 18-冠-6 晶体结构 DMA 介电性能 单晶X射线衍射
  • 简介:建立了非线性热力学模型,定性分析了外加应力和外加温度对外延生长在正交基底上的Pb(Zr1-xTix)O3(PZT)薄膜相变的影响。在外力场下,固定其中一个方向失配应变e1=0.005,模拟得到了不同组分的PZT薄膜的失配应变一外加应力的相图。研究发现,随着Ti组分的减少,出现了新相正交a1c相和四方相a1相,且新相区域也会随Ti组分的不同而变化。在外加拉应力下,c相是薄膜较易出现的相,而在外加压应力下薄膜易处于a1a2相。在不同温度场下,模拟非等轴失配应变的PZT薄膜得到不同组分的PZT薄膜的失配应变一外加温度相图。当组分x≤0.7时,相图中出现了正交a1c相,由于非等轴失配应变的存在,使得从顺电相向r相发生相变的过程中,多出了正交a1a2相;同时另一新的四方a1相也出现在沿失配应变正方向e2被拉伸的区域。随着Ti组分的增加,单斜r相的面积缩小且位置下移。之前存在的四相点也变为了三相点,而正交相a1a2相则向相图的中心位置移动。模拟结果对研究外场下铁电薄膜微器件的性能变化具有一定的指导意义。

  • 标签: 非等轴失配应变 外加应力 外加温度 相图
  • 简介:Tonguesquamouscellcarcinoma(ToSCC)isthemostcommontypeofheadandnecksquamouscellcarcinomaandisthesixthleadingcauseofcancerdeathsworldwide[1].Inclinicaloncology,radiationtherapyisastandardtreatmentusedfortumors.Numerousstudieshaveshownthatconventionalradiotherapyusedincancertreatmentmayincreasetheriskofmetastasisofmalignanttumorcells[2–4].Toimprovepatientsurvival,thepotentialformetastasisoftumorsinresponsetoradiationneedstobeaddressed.

  • 标签: SQUAMOUS Cell CARCINOMA
  • 简介:采用sol-gel方法在石英玻璃衬底上制备出α轴取向的多晶Bi4Ti3O12(BIT)薄膜,根据透射谱曲线得到薄膜样品的线性折射率为2.35,线性吸收系数为9.81×10^3cm^-1,光学带隙宽度为3.60eV。以脉宽300fs,波长800nm的钛蓝宝石脉冲激光为光源,利用单光束Z-scan技术测得薄膜样品的双光子吸收系数为100.31GW·cm^-2,三阶非线性折射率为-1.02×10^2GW·cm^-2。实验结果表明,所制备的BIT铁电薄膜具有大的非线性光学系数,适合应用于光子器件的制备。

  • 标签: BI4TI3O12 铁电薄膜 Z-SCAN 三阶非线性光学
  • 简介:目的:探索燃料富氧燃烧过程中不同浓度CO2的稀释作用对NOx生成的影响,为探索Nx在O2/CO2气氛中生成机理研究提供理论基础。创新点:提出一种无分支链式反应解释说明CO2在还原性粒子环境中对反应的影响。方法:通过ChemkinPro中塞流式反应器模块对混入NH3的CH4燃料在O2/CO2气氛中反应进行数值模拟,同时改变CO2的稀释程度来探索CO2浓度对NOx生成的影响,并比较不同反应机理下的模拟结果,探索此环境中NOx的生成机理(表1)。结论:1.无支链反应机理可用于解释CO2在还原性粒子环境中对Nq生成与还原的影响;2.随着C02浓度的升高,无支链反应和支链反应相互竞争H,进而抑制NO的生成;3.在对NH,转化效率的影响方面,CO2浓度增加引发的无支链反应和支链反应对H的竞争,在富燃料条件下从促进转化变为抑制转化,在化学当量和贫燃料条件下从无影响变为抑制转化。

  • 标签: CO2 富氧燃烧 NO 燃料稀释
  • 简介:PureAl2O3-2SiO2powderswerepreparedbysol-gelandcoprecipitationmethods,andtheiralkaliactivationreactivitieswerecompared.Thealkali-activationreactivityofthepowderpreparedbythesol-gelmethodwashigherthanthatofthepowderpreparedbythecoprecipitationmethod.Thepowderswereinvestigatedby27AIand29Simagic-anglespinningnuclearmagneticresonancespectroscopy(MASNMR)tounderstandtherelationshipbetweentheirstructureandalkali-activationreactivity.The27AlMASNMRdatashowedthatthefive-coordinateAIcontentofthepowderpreparedbythesol-gelmethodwashigherthanthatofthepowderpreparedbycoprecipitation.Thehighercontentoffive-coordinateAlcorrespondedtohigheralkali-activationreactivity.The29SiMASNMRdatashowedthatforthepowderpreparedbythesol-gelmethod,siliconwasreplacedbyaluminumatsecondarycoordinationsitesofthecentralSiatomsduringcalcination.However,forthepowderpreparedbysingle-batchcoprecipitation,themainchangewasfromalowdegreeofpolycondensationtoahighdegreeofpolycondensation.

  • 标签: 魔角旋转核磁共振 活化反应 固体碱 核磁共振光谱 粉末 化学合成
  • 简介:标题化合物C26H26O5以2,3-萘二甲醛和5-甲基-1,3-环己二酮为原料,在醋酸溶剂中,室温下经搅拌多组分一锅法合成得到.其结构通过单晶X-射线衍射法确定,晶体属单斜晶系,空间群P21,相对分子质量Mr=418.47,晶胞参数a=0.99004(8)nm,b=1.09098(9)nm,c=1.04246(11)nm,V=1.08753(17)nm3,Z=2,晶胞密度Dc=1.278g/cm3,吸收系数μ=0.088mm-1,单胞中电子的数目F(000)=444.晶体结构用直接法解出,经全矩阵最小二乘法对原子参数进行修正,最终的偏离因子为R1=0.0533,wR2=0.1293.在晶体结构中新形成的吡喃环为半椅式构象,而茚中五元环则为信封式构象.

  • 标签: 室温 双环化反应 多组分 晶体结构