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: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.
简介:目的观察早期胃癌组织中GTP酶激活蛋白SH3功能区结合蛋白G3BP1和G3BP2的表达变化并探讨其意义。方法选择早期胃癌组织89例和正常对照组织35例,采用免疫组织化学方法检测两组G3BP1蛋白和G3BP2蛋白的表达情况。结果早期胃癌组和正常组G3BP1的阳性率分别为87.64%和60.00%,G3BP2阳性率分别为86.51%和54.28%,两组比较差异有统计学意义(P=0.000,0.000);早期胃癌G3BP1和G3BP2的表达均与幽门螺杆菌感染相关(P=0.000);早期胃癌组织中G3BP1与G3BP2表达呈正相关(rs=0.252,P=0.017)。结论早期胃癌组织中G3BP1和G3BP2呈高表达,可能与幽门螺杆菌感染紧密相关,两指标异常表达可能在早期胃癌的发生和发展中起重要作用。
简介:Alzheimer’sdisease(AD)isoneofthemostdevastatingdiseasesaffectingthelifeandhealthofagingpopulation.TwohallmarksofADaresenileplaquesandneurofibrillarytangles,andADiswellknownforthemassivelossofneuronsandimpairedcognitivefunctionsespeciallymemoryloss.Despiteextensivesearchforeffectivetreatment,available