简介：Statisticalapproachesforevaluatingcausaleffectsandfordiscoveringcausalnetworksarediscussedinthispaper.Acausalrelationbetweentwovariablesisdifferentfromanassociationorcorrelationbetweenthem.Anassociationmeasurementbetweentwovariablesandmaybechangeddramaticallyfrompositivetonegativebyomittingathirdvariable,whichiscalledYule-Simpsonparadox.WeshalldiscusshowtoevaluatethecausaleffectofatreatmentorexposureonanoutcometoavoidthephenomenaofYule-Simpsonparadox.Surrogatesandintermediatevariablesareoftenusedtoreducemeasurementcostsordurationwhenmeasurementofendpointvariablesisexpensive,inconvenient,infeasibleorunobservableinpractice.Therehavebeenmanycriteriaforsurrogates.However,itispossiblethatforasurrogatesatisfyingthesecriteria,atreatmenthasapositiveeffectonthesurrogate,whichinturnhasapositiveeffectontheoutcome,butthetreatmenthasanegativeeffectontheoutcome,whichiscalledthesurrogateparadox.Weshalldiscusscriteriaforsurrogatestoavoidthephenomenaofthesurrogateparadox.Causalnetworkswhichdescribethecausalrelationshipsamongalargenumberofvariableshavebeenappliedtomanyresearchfields.Itisimportanttodiscoverstructuresofcausalnetworksfromobserveddata.Weproposearecursiveapproachfordiscoveringacausalnetworkinwhichastructurallearningofalargenetworkisdecomposedrecursivelyintolearningofsmallnetworks.Furthertodiscovercausalrelationships,wepresentanactivelearningapproachintermsofexternalinterventionsonsomevariables.Whenwefocusonthecausesofaninterestoutcome,insteadofdiscoveringawholenetwork,weproposealocallearningapproachtodiscoverthesecausesthataffecttheoutcome.

简介：Biomedicalsegmentedpolyetherurethane(SPEU)elastomersarecompositepoly-merswithmicrophaseseparationstructure.VariousattemptsofintroducingionicgroupsintoSPEUhavebeencarriedoutfortheimprovementoftheirbloodcompati-bilities.Weherereportthemechanicalandanticoagulantproperties.Twoseriesofsulfooctylpendantgroupscontainingsegmentedpolyetherurethaneswithwelldefinedfinestructurehavebeensynthesizedinourlab-oratory.ThesulfooctylgroupswereexactlylocatedatthehardsegmentswhentheSPEUswerepreparedfromthereactionofpolytetramethyleneglycol(PTMG)1000-4,4’diphenylmethanediisocyanate(MDI)oligomerswithN-sulfoalkyldiethanolamine