简介:用TSQ-70GC/MS/MS色质仪分析了珠江口盆地100余个原油和生油岩样品,发现部分原油样品具有异常丰富的ααα-C29甾烷(20S)异构体。国内外许多学者认为甾烷ααα-C2920S/(20S+20R)值是最有效的成熟度指标,只与成熟度有关,其热成熟平衡值为0.50-0.55。珠江口盆地有部分油样甾烷ααα-C2920S/(20S+20R)值异常之高,最高达0.67,已超过其热平衡值,已超过了当地成熟、过成熟生油岩样品值。确认油源之后,发现离生油凹陷越远,运移距离越大的原油,其甾烷ααα-C2920S/(20S+20R)值越大。因此,ααα-C2920S(20S+20R)不仅与成熟度有关,还与运移距离有关。
简介:本文报道了在合成天然的蛋白酶体抑制剂symgolinA(SylA)及其类似物的过程中,首先合成的两种类型的SylA开环类似物。经过7步反应,第一种类型产物总收率在20%-34%之间,第二种类型产物总收率在12%-18%之间。与SylA相似,这两种类型的类似物也都具有肽乙烯酰胺的结构,可能作为Michael受体与蛋白酶体催化活性位点ThrlO^γ发生1,4-加成反应,从而发挥蛋白酶体抑制活性。
简介:InSeptember,Beijinghadembracedcoolwindandattractivesceneryafteralonghotsummer.AttheinvitationofCAFIU,Mr.ErnstKerbusch,DirectoroftheDepartmentforInternationalDevelopmentCooperationofGermany'sFriedrich-EbertFoundation(FES)andMr.RolandFeicht,newlyappointedresidentrepresentativeinBeijingvisitedBeijing.
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简介:正Cafiu'sSecretary-GeneralNiJianattendedUNSustainableDevelopmentConference(Rio+20)heldinRiodeJaneiro,BrazilfromJune16to21.Thisisanotherlarge-scale,high-leveleventinglobalsustainabledevelopmentafterthe1992UNEnvironmentandDevelopmentConference.The
简介:[目的]研究20(S)-人参皂苷Rg3抗心肌缺血作用及其机制.[方法]随机将50只Wistar大鼠分成5组,即空白对照组(CON),异丙肾上腺素组(ISO),20(S)-人参皂苷Rg3(5、10、20mg/kg)组.各组大鼠灌胃给予相应药物,除CON外其余各组大鼠皮下注射盐酸异丙肾上腺素(20mg/kg)制备心肌缺血模型.末次注射异丙肾上腺素2h后麻醉大鼠,取血检测血清中肌酸激酶(creatinekinase,CK-MB)和乳酸脱氢酶(lactatedehydrogenase,LDH)活力,取大鼠左心室制备匀浆后检测心肌组织超氧化物歧化酶(superoxidedismutase,SOD)活性、谷胱甘肽过氧化物酶(glutathioneperoxidas,GSH-Px)活性、总抗氧化能力(totalantioxygencapabilit,T-AOC)及丙二醛(malonaldehyd,MDA)含量.[结果]与CON组相比,ISO组血清CK-MB、LDH活力明显增高.与ISO组比较,20(S)-人参皂苷Rg3(5,10,20mg/kg)可显著降低血清CK-MB、LDH活力;与CON组比较,ISO组SOD活性、GSH-Px活性及T-AOC降低,MDA含量增高;与ISO组相比,20(S)-人参皂苷Rg3(5、10、20mg/kg)可显著提高SOD活性、GSH-Px活性及T-AOC,降低MDA含量.[结论]20(S)-人参皂苷Rg3具有抗心肌缺血作用,其作用机制与清除自由基和抗脂质过氧化有关.
简介:TheinfluenceofrareearthoxideCeO2onmicrostructureandwearresistanceofM80S20thermalsprayandthermalsprayweldingcoatingsisstudiedusingopticalmicroscope,scanningelectronmicroscope,X-rayenergydispersionspectroscope,X-raydiffractometerandweartestingmachine.Theresultsshowthattheaddi-tionof8%CeO2canimprovethemicrostructure,microhardnessandwearresistanceofcoatingssignificantly.
简介:""Mensaytheyhatetoshop,""saysZhukin,CityUniversityofNewYorkSociology(社会学)professor.""Yetwhenyouaskthemdeeperquestions,itturnsoutthattheyliketoshop.Mengenerallyliketoshopforbooks,musicandhardware.Butifyouaskthemabouttheshoppingtheydoforbooksormusic,they'llsay,'Well,that'snotshopping.That'sresearch.'""