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21.
稀土在鼠肝中的物种分布 总被引:23,自引:0,他引:23
采用 ICP-MS、微量蛋白层析分离技术 ,研究了长时间、低剂量混合稀土及短时间、高剂量硝酸镧分别对大鼠及小鼠作用后 ,稀土在鼠肝中的代谢累积及其物种分布 .结果表明 ,鼠肝中各稀土含量随给药剂量的增加而增大 ,其累积速度大小顺序为 La>Ce>Nd>Pr;经柱层析分离未得到与稀土特异结合的鼠肝蛋白 ;稀土可与多种鼠肝蛋白 (包括多种重要的酶 )结合 ,在一定条件下 ,稀土与其结合蛋白可发生解离 相似文献
22.
We have successfully developed a new one-pot solution-phase route, namely microwave-assisted hydrothermal reduction/carbonization (MAHRC), for a rapid synthesis of coaxial Ag/C nanocables. The nanocables can self-assemble in situ in an end-to-end fashion into interconnected chains. 相似文献
23.
S. P. Ting B. J. Bulkin E. M. Pearce T. K. Kwei 《Journal of polymer science. Part A, Polymer chemistry》1981,19(6):1451-1473
Copolymers of styrene with vinylphenyl trifluoromethyl carbinol, p-vinylphenyl trifluoromethyl carbinol, vinylphenyl hexafluorodimethyl carbinol, and p-vinylphenol are conditionally compatible with poly(ethylene oxide), depending on their composition and blending ratios, whereas copolymers of styrene and vinylphenyl methyl carbinol are much less compatible with poly(ethylene oxide), as determined by Tg criteria and differential scanning calorimetry. The crystallinity of poly(ethylene oxide) is changed in the copolymer/poly(ethylene oxide) blends, as indicated by depressions of the poly(ethylene oxide) melting point. Hydrogen-bond formation has been studied in two selected blends by infrared (IR) spectroscopy. Hydrogen bonding dissociation and reassociation as a function of temperature are reported. The conformation changes of poly(ethylene oxide) in the blends, the interaction between copolymer and poly(ethylene oxide) as well as in the reference blend, polystyrene/poly(ethylene oxide), are also investigated. 相似文献
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As a natural diterpenoid, crotophorbolone possesses a challenging trans,trans-5/7/6 framework decorated with six contiguous stereogenic centers and is structurally and biogenetically related to tigliane-type diterpenoids with intriguing bioactivities such as phorbol and prostratin. Based on the convergent strategy, we completed an eighteen-step total synthesis of crotophorbolone starting from (−)-carvone and (+)-dimethyl-2,3-O-isopropylidene-l-tartrate. The key elements of the synthesis involve expedient installation of the six-membered ring and the five-membered ring with multiple functional groups at an early stage, cyclization of the seven-membered ring through alkenylation of the ketone between the five-membered ring and the six-membered ring, functional group-sensitive ring-closing metathesis and final selective introduction of hydroxyls at C20 and C4.Convergent total synthesis of crotophorbolone was accomplished in 18 longest linear steps. Observation of unexpected thermodynamic stability of a cis,trans-5/7/6 tricycle would benefit synthetic design of tigliane- and daphnane-related diterpenoids. 相似文献
26.
Kohli BM Eng JK Nitsch RM Konietzko U 《Rapid communications in mass spectrometry : RCM》2005,19(5):589-596
In liquid chromatography/tandem mass spectrometry (LC/MS/MS) analyses of complex peptide mixtures, dynamic exclusion functions are used to minimize repeat selections of identical precursors for collision induced dissociation (CID). We describe a new algorithm for the dynamic exclusion of m/z values during LC/MS/MS. Full-scan based peak exclusion (Fulspec) uses a simplified model of chromatographic peak formation to detect and exclude contaminants present throughout the run or that lead to broad peaks. Therefore, instead of excluding peptides from fragment analysis according to a rigidly predefined time window, the chromatographic properties of the detected analytes are used. The algorithm was tested on two datasets derived from previously published experiments. Fulspec achieves a distribution of CID spectra with minimal tailing on the retention time axis, without resorting to rigid exclusion of m/z values. The procedure further excludes intensities with a bias towards low-quality CID spectra. This combination frees up valuable analytical capacity. The underlying intensity vs. quality analyses challenge the assumption that abundant precursors automatically give the best identifications. Further validation of the algorithm will require its incorporation by equipment manufacturers into the instrument control programs. 相似文献
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A Novel Dimeric Coumarin from Clausena lenis 总被引:1,自引:0,他引:1
HongPingHE ShunTingCHEN YueMaoSHEN ChangXiangCHEN YiBinZHAO XiaoJiangHAO 《中国化学快报》2003,14(11):1150-1153
A novel dimeric coumarin (1), a dimeric of seselin named diseselin A, was isolated from the aerial part of Clausena lenis. The structure was elucidated based on the MS, 1D and 2D NMR data. 相似文献
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LeYuWANG HongQiCHEN LingLI LingDONG TingTingXIA LunWANG 《中国化学快报》2004,15(3):319-321
Functionalized nano-PbS has been prepared and characterized. The functionalized nanoparticles have good dispersibility in water. Reaction of functionalized nano-PbS with γ-globulin (γ-IgG) results an enhanced resonance light scattering (RLS) around 385nm.However, when the content of HSA is lower than 0.5μg/ml^-1 the RLS enhancement is very weak and is nonlinear to concentration of HSA. Based on these results, a new direct quantitative determination method for γ-globulin in blood serum samples without separation is established.Under optimal conditions, the enhanced RLS intensity is in proportion to the γ-IgG concentration in the range 10-500ng/mL. The limit of detection is 2.75ng/mL. This method is proved to be very sensitive, rapid, simple and selective for detection of γ-IgG in blood serum. 相似文献