简介:Anenvironmentallyfriendlyprecursor,adenosine,hasbeenusedasadualsourceofCandNtosynthesizenitrogen-dopedcarboncatalystwith/withoutFe.Ahydrothermalcarbonizationmethodhasbeenusedandwateristhecarbonizationmedia.Themorphologyofsampleswith/withoutFecomponenthasbeencomparedbyHRTEM,andtheresultshowsthatFecanpromotethegraphitizationofcarbon.Furtherelectro-chemicaltestshowsthattheoxygenreductionreaction(ORR)catalyticactivityofFe-containingsample(C–FeN)ismuchhigherthanthatoftheFe-freesample(C–N).Additionally,theintermediatesofC–FeNformedduringeachsyntheticprocedurehavebeenthoroughlycharacterizedbymultiplemethods,andthefunctionofeachprocedurehasbeendiscussed.TheC–FeNsampleexhibitshighelectro-catalyticstabilityandsuperiorelectro-catalyticactivitytowardORRinalkalinemedia,withitshalf-wavepotential20mVlowerthanthatofcommercialPt/C(40wt%).Itisfurtherincorporatedintoalkalinepolymerelectrolytefuelcell(APEFC)asthecathodematerialandledtoapowerdensityof100mW/cm~2.
简介:AIM:Toinvestigatetheeffectsofhydrogen-richsaline(HRS)onmicrogliaactivationandSirtuintype1(Sirt1)inratswithN-methyl-N-nitrosourea(MNU)-inducedretinitispigmentosa(RP).METHODS:Ratsweredividedintonorm(N)group,model(M)groupandHRS(H)group.RatsinMandHgroupsweregivensalineandHRSrespectivelypriortoandafteradministrationofMNU.Atoneday(d1)andd3afterwards,electroretinogramandhistologicalexaminationwereperformedtoconfirmtheeffectsofHRSonretinalfunctionandstructureofMNU-inducedRP.Immunofluorescencestainingofanti-ionizedcalcium-bindingadaptermolecule1(Iba1),amakerofmicrogliacells,wasperformed,withquantitativereal-timepolymerasechainreaction(qRT-PCR)foritsmRNAquantification.Moreover,Sirt1mRNAandproteinexpressionintheretinasweredetectedbyWesternblotandqRT-PCR.RESULTS:HRSpreservedtheretinalfunctionandmitigatedthereductionofphotoreceptordegenerationinMNU-treatedretinas.ThepresenceofmicrogliacellswassomewhatmoreobviousinHgroupthanthatinMgroupatd1.HRSsuppressedthefurtheractivationofmicrogliacells,withthenumberofmicrogliacellslessthanthatofMgroupatd3.ResultsofqRT-PCRofIba1wereconsistentwiththoseofimmunofluorescencestaining,withthemRNAexpressionofIba1inHgroupmoreintensivethanthatofMgroupatd1(P<0.05),whilelessthanthatofMgroupatd3(P<0.05).Furthermore,theSirt1mRNAandproteinexpressiondecreasedafterMNUadministration,whileHRSmitigatedtheMNU-induceddownregulationofSirt1.CONCLUSION:HRScaneffectivelykeepmicrogliaactivationinducedbyMNUtoanappropriateextent,whileupregulateSirt1inMNU-inducedRP.
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简介:应用密度泛函理论中的ω-B97XD/6-311+G(d,p)方法,对甲湛分子团簇[CH2O]n(n=1~4)的空间结构进行了优化,得到了这些团簇的基态结构,并对其红外光谱,核磁共振谱的性质进行了研究.结果表明,当甲醛分子构成稳定的多分子团簇时,团簇中的每个分子仍然为平面结构,分子间将形成氢键,并且团簇中的各个分子共面.与单分子甲醛相比,多分子团簇的红外光谱,会出现许多与分子间氢键振动有关的新的吸收峰.当甲醛分子形成团簇时,13C核和17O核的核磁共振谱线会发生劈裂现象,这与电荷分布的对称性的破缺有关;而1H的核磁共振谱中将会出现新的条纹,这是由分子间的氢键的形成引起的.本文的研究可为甲醛团簇的识别、检测及性质研究提供理论依据.
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简介:「N1+あふれる+N2」结构是日语中出现频率颇高的语言表现形式。本文认知语义学角度,以共时层面考察日语「N1+あふれる+N2」结构的语义特征和句法特征,阐述在这一结构中动词「あふれる」语义发生功能类转的特点,即由表现动词典型情状的事件范畴转变为与形容词功能类似的属性范畴,句法功能也由陈述描写性功能向属性定性功能转变,即“事件→状态→属性”的语义演变过程。通过对「N1+あふれる+N2」语义的规约性、类转及其外在形式的融合等词汇化要素的检验,论证了「N1+あふれる+N2」具有词汇化倾向。
简介:乙酸(1-二茂铁基乙基)酯1与二甲胺反应制备出N,N-二甲基-1-二茂铁乙胺2,收率74%.在正丁基锂/乙醚的反应体系中,化合物2进一步与二苯基氯化磷反应,制备出N,N-二甲基-1-(2-二苯膦基)二茂铁乙胺3,收率18%.化合物3的结构经1HNMR和31PNMR进行了表征,并进一步研究了其合成机理.
简介:Airtemperatureisakeyindexreflectingclimatechange.Airtemperatureextremesareveryimportantbecausetheystronglyinfluencethenaturalenvironmentandsocietalactivities.TheArcticairtemperatureextremesnorthof60°Nareinvestigatedinthewinter.Dailydatafrom238stationsatnorthof60°Nfromtheglobalsummaryofthedayfortheperiod1979–2015areusedtostudythetrendsofcolddays,coldnights,warmdaysandwarmnightsduringthewintertime.Theresultsshowadecreasingtrendofcolddaysandnights(rateof–0.2to–0.3d/a)andanincreasingtrendofwarmdaysandnights(rateof+0.2to+0.3d/a)intheArctic.Themeantemperatureincreases,whichcontributestotheincreasing(decreasing)occurrenceofwarm(cold)daysandnights.Ontheotherhand,thevarianceatmoststationsdecreased,leadingtoareducednumberofcoldevents.ApositiveAO(ArcticOscillation)indexleadstoanincreased(decreased)numberofwarm(cold)daysandnightsovernorthernEuropeandwesternRussiaandanincreased(decreased)numberofcold(warm)daysandnightsovertheBeringStraitandGreenland.ThelowerextentofArcticautumnseaiceleadstoadecreasednumberofcolddaysandnights.TheoccurrencesofabruptchangesaredetectedusingtheMann-KendallmethodforcoldnightsoccurringinCanadain1998andforwarmnightsoccurringinnorthwesternEurasiain1988.ThisabruptchangemainlyresultedfromthemeanwarminginducedbysouthwindsandanincreasedNorthAtlanticseasurfacetemperature.