简介:Inthispaper,weprovethatifGisaplanegraphwithout4-,5-and7-circuitsandwithoutintersectingtriangles,thenforeachfacefofdegreeatmost11,any3-coloringoftheboundaryoffcanbeextendedtoG.ThisgivesapositivesupporttoaconjectureofBorodinandRaspaudwhichclaimsthateachplanegraphwithout5-circuitsandintersectingtrianglesis3-colorable.
简介:Forelectronicmicroscopicobservation,wefoundSSV-transformedNIH3T3cellsweredifferentfromnon-transformedcells.InSSV-transformedNIH3T3cellsnucleicytoplasmaratiowasincreasedandincytoplasmatheribosomes(polyribosomeswereattachedtotheswollenroughendoplasmicreticulum.Itwaslikelythatribosomeswerelinedtogetherfunctionallyandstructionallytoproducespecificprotein(PDGF-likeprotein).
简介:Objective:ToexploretheeffectsofnuclearM-CSFontheprocessoftumorigenesis.Methods:FunctionalpartofM-CSFcDNAwasinsertedintoaneukaryoticexpressionplasmidpCMV/myc/nuc,whichcanaddthreeNLStotheC-terminaloftheexpressedproteinanddirecttheproteinintothecellnuclei.TheconstructedplasmidwastransferredintoNIH3T3cellsandthecellcloneswereselectedbyG-418selection.CellclonesstableexpressingtargetproteinwereidentifiedbyRT-PCR,ABCimmunohistochemistryassayandWesternblot.Cellgrowthkineticsanalysesthroughgrowthcurves,celldoublingtime,MTTtestandanti-senseoligodeoxynucleotide(ASODN)inhibitingcellgrowthtestwereperformedtoidentifycellsproliferationpotential.Results:Thetransfectedcellsshowedelevatedproliferationpotentialoverthecontrolcells.Conclusion:AbnormalappearanceofM-CSFinnucleuscouldenhancecellproliferation,whichsuggeststhatcytokineisoformswithincellnucleusmightplaytranscriptionfactor-likerole.
简介:Copolymerizationofstyrene(St)andisoprene(IP)wascarriedoutwithacatalystsystemcomposeaofanhydrouslanthanidechloridehexamethylphosphoramidecomplex(LnCl3·HMPA)andaluminumorganiccompound(AOC).Amongthecatalystsexamined,catalystNdCl3·HMPA/AI(i-Bu)3showedahighactivityinthecopolymerizationundercertainconditionsgivingcopolymers(5%—15%Stcontent)withhighcis-1,4microstructureinIPunits(>95%).TheeffectsofHMPA/Ndmolarratio,Al/Ndmolarratio,monomer/Ndmolarratio,Stfeedratio,andthereactiontimeoncopolymerizationwereexaminedwiththiscatalyticsystem.Theobtainedcopolymerswerecharacterizedby^1Hand^13CNMRspectroscopiesandgel-permeationchromatography(GPC).