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采用稀土催化体系Nd(F_3CO_2)_3-BrC_5H_(11)-R_mAlH_(3-m)(Nd-Br-Al),以甲苯为溶剂,在50℃恒温水浴中进行苯乙烯(St)和异戊二烯(Ip)共聚合。结果表明,由Al(Oct)-3组成的催化体系可制备以顺式-1,4结构为主的共聚物;在后者组成的催化体系中,当Al/Nd=5(摩尔比,下同),Br/Nd=5时,聚合活性最高。经IR,NMR检测表征了共聚物的微观结构。同时,用π-烯丙基型配位机理和返扣配位机理对实验结果进行了定性解释。 相似文献
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Thedevelopmentofhigh fieldNMRspectrome terswithincreasedsensitivity,resolution,dynamic rangeandimprovedcomputingcapabilitieshasmade itpossibletouseNMRtechniqueforrapidmulticom ponentanalysisoflowMWcompoundsinbiofluids inordertoassessthetoxicologicaleffe… 相似文献
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Investigation on Acute Biochemical Effects of Ce(NO3 )3 on Liver and Kidney Tissues by MAS 1H NMR Spectroscopic-Based Metabonomic Approach 总被引:2,自引:0,他引:2
High resolution1Hmagicanglespinning(MAS)NMRspectroscopyisincreasinglybeingusedasause fultechniqueforinvestigatingthemetabolicstateof variousintacttissuesintheareasofdrugtoxicity[1,2]anddiseasediagnosis[3,4].Biologicaltissuesaresemi solidheterogeneouscomplexcontainingspecieswitha widerangeofmolecularweightssuchasproteins,lip ids,andlow molecularweightmetabolites[5].1HNMR spectraoftissuesufferfrommajorline broadeningcon tributionswhenacquiredbyconventionalsolution state NMRspectroscopybecau… 相似文献
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Biochemical effects of gadolinium chloride in rats liver and kidney studied by ^1H NMR metabolomics 总被引:1,自引:0,他引:1
The biochemical effects of gadolinium chloride were studied using high-resolution IH nuclear magnetic resonance (NMR) spec-troscopy to investigate the biochemical composition of tissue (liver and kidney) aqueous extracts obtained from control and gadolinium chlo-ride (GdCl3) (10 and 50 mg/kg body weight, intraperitoneal injection, i.p.) treated rats. Tissue samples were collected at 48, 96 and 168 h p.d. after exposure to GdCl3, and extracted using methanol/chloroform solvent system. 1H NMR spectra of tissue extracts were analyzed by pat-tern recognition using principal components analysis. The liver damages caused by GdCl3 were characterized by increased succinate and de-creased glycogen level and elevated lactate, alanine and betaine concentration in liver. Furthermore, the increase of creatine and lactate, and decrease of glutamate, alanine, phosphocholine, glycophosphocholine (GPC), betaine, myo-inositoi and trimethylamine N-oxide (TMAO)levels in kidney illustrated kidney disturbance induced by GdCl3. 相似文献
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The heavy lanthanide ions(Dy,Ho,Er,Tm and Yb)were used to probe the conformation of L-arginine inaqueous solution.The results showed that the contact contribution to the observed~(13)C paramagnetic shift is verysmall for nuclei four or more bonds away from the bound lanthanide ion and it is significant for those in closeproximity to the lanthanide ion.The overall conformation of L-arginine was established by fitting the calculatedgeometric factors for the corresponding experimental data.In the lanthanide-L-arginine complex,the wholebackbone of the ligand is located outsite the zero-dipolar shift cone of the lanthanide ion with the carboxyl groupselectively coordinated to the metal.The calculated RE-O distance is 0.21 nm for the bidentate coordinationmode and the ligand is in an extended conformation in the solution with the molecular backbone corresponding tothe trans form. 相似文献
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NMRStudiesofη~3-AllylRareEarthMetalComplexesLiFeng-Fu;(李凤富);JinYing-Tai;(金鹰泰);RenJi-Min;(任吉民);SunYu-Fang;(孙玉芳);PeiFeng-Kui;(裴?.. 相似文献
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NMRspectroscopyofbiofluidhasbroughtnew chemistryintolifescienceandclinicalmedicine,and NMRspectroscopy basedapproachhasbeensuccess fullyappliedtothestudiesofbiochemicaleffectsand inborndiseaseswiththeadventofhighfieldNMR spectrometers[1].Inrecentyears,highresolutionNMRhasbeenusedtotherapidmulticomponentanal ysisoflowmolecularweightcompoundsinbiofluid,includingurine,bile,cerebrospinalfluid,saliva,milkandsynovialfluidforclinicaldiagnosisofinborn diseasesandinvestigationofbiochemicaleffectsof… 相似文献
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