简介:TheauthorsintroduceandinvestigatetheT_C-Gorensteinprojective,L_CGorensteininjectiveandH_C-GorensteinflatmoduleswithrespecttoasemidualizingmoduleCwhichsharesthecommonpropertieswiththeGorensteinprojective,injectiveandflatmodules,respectively.TheauthorsprovethattheclassesofalltheT_C-GorensteinprojectiveortheH_C-GorensteinflatmodulesaxeexactlythoseGorensteinprojectiveorfiatmoduleswhichareintheAuslanderclasswithrespecttoC,respectively,andtheclassesofalltheL_C-GorensteininjectivemodulesaxeexactlythoseGorensteininjectivemoduleswhichareintheBassclass,sotheauthorsgettherelationsbetweentheGorensteinprojective,injectiveorflatmodulesandtheC-Gorensteinprojective,injectiveorflatmodules.Moreover,theauthorsconsidertheT_C(R)-projectiveandL_C(R)-injectivedimensionsandT_C(R)-precoversandL_C(R)-preenvelopes.Finally,theauthorsstudytheH_C-GorensteinflatmodulesandextendtheFoxbyequivalences.
简介:ThebindingofCo(bpy)2dppz3+tocalfthymusDNAwasinvestigatedbyusingabsorptionandemissionspectroscopy,DNAmeltingtechniques,cyclicvoltammetry,viscosityandelectro-phoresismeasurements,wherebpyis2,2’-bipyridyl,dppzisdipyrido[3,2-o:2’,3’-c]phenazine.Thebindingcompoundshowsabsorptionhypochromicity,fluorescenceenhancement,andincreasingofDNAmeltingtemperatureandthespecificviscosity.CVmeasurementshowstheshiftsinoxidation-reductionpotentialandchangeinpeakcurrentwithadditionofDNA.ThecompoundisalsoshowntobemoreefficientphotosensitisersforstrandbreaksinplasmidDNA.
简介:DNAcondensationisanimportantprocessinmanyfieldsincludinglifesciences,polymerphysics,andappliedtechnology.Inthenucleus,DNAiscondensedintochromosomes.Inpolymerphysics,DNAistreatedasasemi-flexiblemoleculeandapolyelectrolyte.Manyagents,includingmulti-valentcations,surfactants,andneutralpoorsolvents,cancauseDNAcondensation,alsoreferredtoascoil–globuletransition.Moreover,DNAcondensationhasbeenusedforextractionandgenedeliveryinappliedtechnology.ManyphysicaltheorieshavebeenpresentedtoelucidatethemechanismunderlyingDNAcondensation,includingthecounterioncorrelationtheory,theelectrostaticzippertheory,andthehydrationforcetheory.Recentlyseveralsingle-moleculestudieshavefocusedonDNAcondensation,sheddingnewlightonoldconcepts.Inthisdocument,themulti-fieldconceptsandtheoriesrelatedtoDNAcondensationareintroducedandclarifiedaswellastheadvancesandconsiderationsofsingle-moleculeDNAcondensationexperimentsareintroduced.
简介:TheeffectofCdionsonsalmonspermDNAwasstudiedbymeansofcirculardichroism(CD),Ramanspectroscopy,X-rayphotoelectronspectroscopy(XPS)andfluorescencespectroscopy.TheCDspectralandfluorescentprobe-acriflavineresultsindicatethattheDNAunderwentaconformationchangeupontheadditionofCdions.XPSandRamanstudiesrevealthatthereexistedinteractionsbetweenCdionsandthephosphategroupsoftheDNA.Inaddition,anewbandappearedat803cm-1intheRamanspectra,whichcanbeattributedtocharacterizing"marker"bandofA-DNA.ItisconcludedthatCdionscanbecoordinatedbythephosphategroupsoftheDNAandinducetheconformationchangesoftheDNAfromB-DNAtoA-DNA.
简介:HydrolysisofDNAisanimportantenzymaticreaction,butitisexceedinglydifficulttomimicinthelaboratorybecauseofthestabilityofhydrolysisofDNA.Inthispaper,thecleavageactivityofcomplexesformedbetweenCu(Ⅱ)andfourdifferentaminoacidoraminoacidmethylesteronDNAisstudiedbygelelec-trophoresis.ItisfoundthatDNAcouldbecleavedbyCu(Ⅱ)-L-HisandCu(Ⅱ)-L-Hismethylestercomplexesandtheefficiencyofcleavageislargelydependentonthemetalion-to-ligandratio.FurtherexperimentsshowthatthecleavageofDNAmediatedbyCu(Ⅱ)-L-HiscomplexesoccursviaahydrolyticmechanismandtheactivechemicalspeciesthataffectsDNAcleavageisproposedtobeMI2H+andML2H22+.
简介:AdoublehelixmodelofchargetransportinDNAmoleculeisgivenandthetransmissionspectraoffourDNAsequencesareobtained.ThecalculatedresultsshowthatthetransmissioncharacteristicsofDNAarenotonlyrelatedtothelongitudinaltransportbutalsotothetransversetransportofmolecule.Theperiodicsequencewiththesamecompositionhasstrongerconductionability.Withtheincreasingofbasescomposition,theconductiveabilityreduces,buttheweightofθdirectionrisesinchargetransfer.
简介:Thetitlecomplex[NH_3CH_2CH(NH_2)CH_3]_2[M(Ⅵ)O_2(OC_6H_4O)_2](M=Mo_(0.6)W_(0.4))wassynthesizedviaasimplesolution-phasechemicalroute.ThedeterminationofsinglecrystalX-raydiffractionrevealedthatthetitlecompoundiscrystallizedinamonoclinicsystemwithP2(1)/nspacegroup,a=1.0913(10)nm,b=1.0442(10)nm,c=1.8842(19)nm,α=90°,β=96.530(17)°,γ=90°,Z=4,andV=2.133(4)nm3.Themononuclearanionicunit[M(Ⅵ)O2(OC6H4O)2]2-displayschiralpseudo-octahedral[MO_6]coordinationgeometryandislinkedbychiralcationsviahydrogenbondandπ…πstackinginteraction.Thetransmissionelectronmicroscopyimagesshowthatthetitlecomplexiscomprisedofnano-particleswithdiametersrangingfrom20to50nm.TheNMRstudyshowsthe1Hdownfieldchemicalshiftsof[NH_3CHaHbCH(NH_2)CH_3]+cationsinthetitlecomplexwhenitismixedwithadenosine-triphosphate(ATP),andthechemicalshiftdifferencebetweenHaandHbisincreasedgreatly,andmostofthecatecholateligandsdissociatefromthecentralmetalatoms.TheDNAcleavageactivityexperimentrevealsthatDNAcleavagepromotedbythetitlecomplexislowerthanthatbyNa_2MoO_4whichpossessesantitumorpro-perty,buthigherthanthatbyNa_2WO_4.
简介:Adetectionofanthracyclineantitumordrugdaunomycin(DNR)reactingwithDNAinsimulatemetabolisminvitrohasbeenmade.ItwasfoundthatDNRcouldreactwithDNAtoformDNR-DNAadducts.TheadductcompositionsofDNRwithfishspermDNAandthermallydenaturatedDNAweredetermined.TheequilibriumassociationconstantKofDNRwithfishspermDNAis1.98×10^5L/molandthatofDNRwithdenaturatedDNAis2.29×10^4L/mol.Semiquinonefreeradicals,metabolicproductsofDNR,candestroybothfishspermDNAanditsthermallydenaturatedDNA.ItisverifiedbyhyperchromiceffectincreaseobservedinUVspectrumandAFMexperiments.ThemechanismofDNAdegradationhasalsobeeninvestigated.Resultsobtainedallowonetoexplainthereasonofsideeffectofanthracyclinedrugandgivethewaytodepress,whichwereofclinicalsignificance.