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简介：Poly(ethyleneterephthalate)(dacron,PET)filmswereexposedunderargonplasmaglowdischargewithdifferentglowsandinducedpolymerizationofacrylicacid(AA)inordertointroducecarboxylicacidgroupontoPET(PET-AA)assistedbyultravioletradiation(UV).HirudinimmobilizedPET(PET-HRD)filmswerepreparedbythegraftingofPET-AA,followedbychemicalreactionwithhirudin.ThesurfacestructureofthetreatedPETwasdeterminedbyX-rayphotoelectronspectroscopy(XPS).Thewettability,surfacefreeenergy,andinterfacefreeenergyofthefilmswereinvestigatedbycontactanglemeasurement.Thebloodcompatibilityofthefilmswasassessedbyplatelet-adhesiontestandfibrinogenconformationalchangemeasurementstoevaluatetheviabilityofthematerialsinbiomedicalengineering.Measurementbyscanningelectronmicroscopy(SEM)revealedthattheamountsofadhered,aggregatedandmorphologicallychangedplateletswerereducedonthehirudin-immobilizedPETfilms.Enzyme-linked-immunoassaymeasurementsthatdisclosedfibrinogenconformationalchangesshowedresultsconsistentwiththeplatelets’behavior.

简介：Inthisstudy,commercialpolyvinylchloride(PVC)filmsweretreatedbyoxygenandargonplasmasinacylindricalglasstubewhichwassurroundedbyaDCvariablemagneticfield,withdifferentsamplepositionsintheplasmareactorandalsodifferentexposuredurations.Effectsoftheplasmatreatmentonthehydrophilicpropertiesofthefilmswerestudiedbymeasuringthewaterdropcontactangleonthesurfaceofthesamples.Thesurfacetopographyoftheuntreatedandplasmatreatedfilmswasanalyzedandcomparedbyatomicforcemicroscopy(AFM).Theopticalcharacteristicchangesintreatedsampleswereinvestigatedusingreflectivespectrophotometry.Also,thechemicalchangeswhichappearedonthesurfaceofthesampleswereinvestigatedusingFouriertransforminfraredspectroscopy(FTIR).TheresultsshowthattheplasmatreatedPVCbecomesmorehydrophilicwithanenhancedwettability.Asharpdecreaseinthewatercontactanglemayalsobeaconsequenceofthesurfacetexturization.Theagingeffectonwettabilityofthesampleswasalsoinvestigated.Theresultsshowthattheeffectofoxygenplasmaonthesurfacepropertiesofthesamplesismorepronouncedcomparedwiththatofargonplasma.

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简介：ToobtainthermotolerantmutantsofG.oxydans,whichcanenhancethetransformationrateofL-sorboseto2-Keto-L-gulonate(2-KLG)at33℃inatwo-stepprocessofvitaminCmanufacture,ionbeamwasusedasamutationsource.GluconobacteroxydansGOandBacillusmegateriumB0wereusedinthisstudy.TheoriginalstrainGluconobacteroxydansGOwasmutatedbytheheavyionimplantationfacilityattheInstituteofPlasmaPhysics,ChineseAcademyofSciences.SeveralmutantsincludingGluconobacteroxydansGI13wereisolatedandcoculturedwithBacillusmegateriumB0at33℃inshakingflasks.TheaveragetransformationrateofthenewmixedstrainGI13-B0inpergram-moleculereached94.4%aftersevenpassagesinshakingflasks,whichwasincreasedby7%whencomparedwiththeoriginalmixedstrainG0-B0(GluconobacteroxydansG0andBacillusmegateriumB0).Moreover,thetransformationrateofI13B0wasstableat94%attemperaturesrangingfrom25℃to33℃,whichwouldbeofmuchvalueinreducingenergyconsumptioninthemanufactureofL-ascorbicacid,especiallyintheseasonofsummer.Toclarifysomemechanismofthemutation,thespecificactivitiesofL-sorbosedehydrogenaseinbothG0andGI13wereestimated.

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