简介:摘要目的应用液质联用(LC-MS/MS)技术,建立农产品中黄曲霉毒素B1、B2、G1、G2的定量检测方法,对市场中的农产品进行分析。方法样品粉碎后经乙腈水(84+16)提取,不经免疫亲和柱净化,氮吹浓缩定容后过0.22μm滤膜。滤液经反向C18柱分离,以0.1%甲酸水-甲醇作流动相梯度洗脱分离4种黄曲霉毒素。质谱采用电喷雾离子化源(ESI),正离子模式扫描。结果4种毒素在各自的定量范围内均呈良好的线性关系,r>0.990,回收率>80%,且与经免疫亲和柱净化相比,具有较高的回收率。结论该方法具有简便、快速、经济、灵敏、准确等优点,适用于多种农产品中黄曲霉毒素的检测。
简介:TheemergenceofB2Belectronicmarketshasgreatlychangedtherelativebargainingpowerofbuyersandsellers.Westudytheequilibriummarketstructureinabuyer’smarket.Wefindthatbuyer-controlledB2BmarketsandneutralB2Bmarketshavedifferentequilibriumstructures,andtheemergenceofB2Bmarketswillincreasesocialwelfare,butitseffectonbuyersandsellerswillbedifferent:B2Bmarketsincreasetheconsumersurplusoftheendmarket,buttheireffectsonbuyerandsellerprofitsaremoderatedbytherelativebargainingpowerofbuyersandsellers.TheprofitsofthesidewithmuchweakerbargainingpowerwilldecreaseduetotheintroductionofB2Bmarkets.
简介:Duetotheexistenceofthermaloffsets,globalsolarirradiancesmeasuredbypyranometersaresmallerthanactualvalues,anderrorsarelargerinthedaytime.Untilnow,thereisnouniversally-recognizedcorrectionmethodforthermaloffseterrors.Therefore,itisimperativetoidentifyaconvenientandeffectivecorrectionmethod.Fivecorrectionmethodswereevaluatedbasedonthedatameasuredfromafieldexperimentfrom23Januaryto15November,2011.Resultshaveshown:1)Temporalvariationcharacteristicsofthermaloffsetsinthefourtestedpyranometersareconsistent.2)Amongthefivemethods,non-dimensionalquantitymethodissuggestedforusetocorrectthermaloffsets,becauseitisconvenientandnomodificationofinstrumentsisrequired.Ifcollocatednetlongwaveradiationandwindspeeddataareavailableandtheiruncertaintiesaresmall,thehistoricalsolarradiationdatasetscanalsobecorrected.Andcorrectioneffectsbythemethodarebetter.
简介:Thereisagrowingsupportforthelowlyingscalarmesonsf0(500),f0(980),a0(980),and(800)tobegenerateddynamicallyfromtheinteractionofpseudoscalarmesons,whilethecaseofthenextsetofscalarresonancesathigherenergies,f0(1370),f0(1710),K0(1430)ismoreaquestionofdebate.Soisthecaseofthetensorresonancesf2(1270),f′2(1525),K2(1430).AnewperspectiveonthesestateshasbeenofferedinRef.[1]wherethef0(1370)andf2(1270)resonancesareshowntobegeneratedfromtheinteractionprovidedbythelocalhiddengaugeLagrangiansimplementingunitarization.Itisshownthattheideaofthenatureofthesestatesasvectormeson-vectormesoncompositestateshasbeentestedinmanyreactions.Yet,thepermanentdiscussionoftheissuedemandsextrachecksforotherobservablesand,inthissense,theweakdecaysbringanewsourceofvaluableinformationthatshouldservetotestdifferentmodels.
简介:Objective:TheresultsofapreviousstudyshowedthatacleardysregulationwasevidentintheglobalgeneexpressionoftheBCL11A-suppressedB-lymphomacells.Inthisstudy,thebonemorphogeneticproteinreceptor,typeII(BMPR2),E1Abindingproteinp300(EP300),transforminggrowthfactor-β2(TGFβ2),andtumornecrosisfactor,andalpha-inducedprotein3(TNFAIP3)geneexpressionpatternsinB-cellmalignancieswerestudied.Methods:TherelativeexpressionlevelsofBMPR2,EP300,TGFβ2,andTNFAIP3mRNAinB-lymphomacelllines,myeloidcelllines,aswellasincellsfromhealthyvolunteers,weredeterminedbyreal-timequantitativereversetranscriptpolymerasechainreaction(qRT-PCR)withSYBRGreenDye.Glyceraldehyde-3-phosphatedehydrogenase(GAPDH)wasusedasreference.Results:TheexpressionlevelofTGFβ2mRNAinB-lymphomacelllineswassignificantlyhigherthanthoseinthecellsfromthehealthycontrol(P<0.05).However,theexpressionlevelofTNFAIP3mRNAinB-malignantcellswassignificantlylowerthanthatofthehealthycontrol(P<0.05).TheexpressionlevelsofBMPR2andEP300mRNAshowednosignificantdifferencebetweenB-malignantcelllinesandthehealthygroup(P>0.05).InB-lymphomacelllines,correlationanalysesrevealedthattheexpressionofBMPR2andTNFAIP3(r=0.882,P=0.04)hadsignificantpositiverelation.TheexpressionlevelsofBMPR2,EP300,andTNFAIP3mRNAincelllinesfrommyeloidleukemiaweresignificantlylowerthanthoseinthecellsfromthehealthycontrol(P<0.05).TheexpressionlevelsofTGFβ2mRNAshowednosignificantdifferencebetweenmyeloidleukemiacelllinesandthehealthycontrolorB-malignantcelllines(P>0.05).TheexpressionlevelsofBMPR2,EP300,andTNFAIP3mRNAinB-lymphomacellsweresignificantlyhigherthanthoseofthemyeloidleukemiacells(P<0.05).Conclusion:DifferentexpressionpatternsofBMPR2,EP300,TGFβ2,andTNFAIP3genesinB-lymphomacellsexist.更多还原
简介:目的观察活血祛痰法对糖尿病肾病大鼠核转录因子-κB(NF-κB)信号传导通路的影响,探讨其对DN防治作用及机制.方法建立糖尿病肾病(DN)大鼠模型,随机分为正常组、模型组、中药组,观察各组大鼠24h饮水量、24h尿蛋白量、血肌酐、空腹血糖水平等指标;病理切片过碘酸雪夫(PAS)染色观察肾脏的病理改变;采用一步法定量PCR检测肾组织NF-κB基因的表达;免疫印迹法(Westernblot)检测P65蛋白质含量.结果治疗后,模型组尿蛋白量较正常组呈上身趋势,中药组治疗后,24h尿蛋白量、血肌酐明显低于模型组(P<0.01);模型组NF-κB基因在肾脏中表达量明显高于正常组,治疗后,中药组NF-κB基因在肾脏中表达水平较模型组明显下调(P<0.01);相对于模型组P65蛋白表达上调,中药组治疗后P65蛋白表达量下降,接近正常组.结论活血祛痰法可用于治疗早期糖尿病肾病,机制可能与其能抑制DN大鼠肾脏中NF-κB信号传导通路的激活有关.
简介:Objective:TodeterminewhetherInterferon-alpha-2b(IFN-α2b)canmodulatetheautophagicresponseinhepatocellularcarcinomacells.Methods:HepatocellularcarcinomacellsweretreatedwithIFN-α2b.Autophagywasassessedbyacridineorangestaining,GFP-LC3dottedassay,transmissionelectronmicroscopyandimmunoblotting.Results:AcridineorangestainingshowedthatIFN-α2btriggeredtheaccumulationofacidicvesicularandautolysosomesinHepG2cells.TheacridineorangeHepG2cellratioswere(4.3±1.0)%,(6.9±1.4)%,and(13.1±2.3)%,respectively,aftertreatmentwith100,1,000,and10,000IU/mLIFN-α2bfor48h.AmarkedlypunctatepatternwasobservedinHepG2cellstreatedwith10,000IU/mLIFN-α2bfor48h,butonlydiffuseandweaklyfluorescentGFP-LC3punctawasobservedincontrolcells.HepG2cellstreatedwith10,000IU/mLIFN-α2bfor48hdevelopedautophagosome-likecharacteristics,includingsingle-ordouble-membranevacuolescontainingintactanddegradedcellulardebris.TheBeclin1andLC3-IIproteinexpressionwasup-regulatedbyIFN-α2btreatment.Conclusion:Autophagycanbeinducedinadose-dependentmannerbytreatmentwithIFN-α2binHepG2cells,andtheBeclin1signalingpathwaywasstimulatedbyIFN-α2b.