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71.
A capillary electrophoresis (CE) method was developed for the separation of heparin oligosaccharides compatible to study the interactions between the oligosaccharides and granulocyte-colony stimulating factor (G-CSF). Unfractionated heparin was eliminitively degraded to heparin oligosaccharides by an endolytic heparinase. The degraded smaller oligosaccharides (M(r) < 1000) were baseline-separated by CE under a 50 mM phosphate buffer (pH 9.0) in 10 min. Standard heparin disaccharides and larger oligosaccharides (1000 < M(r) < 8000) were all separated under optimized separation conditions. Compared with standard heparin disaccharides, smaller oligosaccharides contained one nonsulfated, two monosulfated, and two disulfated disaccharides, but trisulfated disaccharides were not found. The smaller oligosaccharides were also identified and molecular mass was deduced by electrospray ionization-mass spectrometry (ESI-MS). Furthermore, interactions between G-CSF and the oligosaccharides were studied by using capillary zone electrophoresis (CZE) under the above separation conditions. It was found that larger oligosaccharides could interact with G-CSF while smaller oligosaccharides were not observed to bind to G-CSF under the experimental conditions. In conclusion, the purified heparinase could selectively degrade heparin into oligosaccharides and the interaction between G-CSF and heparin was correlated with the chain length of heparin. 相似文献
72.
Yao Zu Liao Mei Hua Xin Ming Chun Li Sheng Su College of Materials Science Engineering Huaqiao University Quanzhou China 《中国化学快报》2007,18(2):213-216
O-Lauroyl chitosan/poly(L-lactide) (OCS/PLLA) blend membranes with different compositions were prepared by solution-casting approach using chloroform as common solvent. The experimental results of FT-IR, DSC and WAXD indicated that inter-association hydrogen-bond interactions existed between OCS and PLLA in the blend membranes. And SEM observation confirmed that the blend membranes with suitable compositions were compatible. 相似文献
73.
Thermal treatment of Zn(NH3)(4)2+ precursor in ethanol solvent led to the formation of the tubular ZnO which exhibited strong ultraviolet photoluminescence around 385 nm at room temperature; TEM images showed the hollow tubules with approximately 450 nm in diameter and approximately 4 microns in length were built up by ZnO polycrystals. 相似文献
74.
Synthesis of camphor derived chiral allenes and their hydroboration-oxidation reactions are described. Reaction of (1R)-(+)-camphor with alkynyllithium followed by the reduction of the resulted propargyl alcohol derivatives using AlH3 furnished chiral allenes 2a-g in excellent yields with high diastereoselectivity. Reduction of the propargyl alcohols with aluminum hydride proceeded through selective intermolecular anti-addition of hydride ion. The stereochemistry of the chiral allenes 2 was assigned based on lanthanide shift studies and chemical correlations. Diastereoselectivity was observed in the hydroboration-oxidation of 2 which produced a mixture of (E,R) and (E,S) stereoisomers in a ratio of 6:1 to 18:1. 相似文献
75.
Summary Three novel heterotrinuclear complexes have been prepared, [Cu2(oxdn)2Zn](ClO4)2 (1) and [Cu2(oxdn)2-M(H2O)2](ClO4)2 with M=Mn (2) and Co (3) [oxdn-oxamidobis (propionato)], and characterized by spectral data. The temperature dependence of the magnetic susceptibilities of (2) and (3) has been studied in the 4–300K range, and the exchange integrals J=–20.90cm–1 for (2) and J=–62.36cm–1 for (3) calculated. These results are commensurate with antiferromagnetic interactions between the adjacent metal ions. 相似文献
76.
Yan Ouyang Wei Zhang Yue Ma Na Xu Dai-Zheng Liao Kazuyoshi Yoshimura Shi-Ping Yan 《Structural chemistry》2007,18(6):891-898
Two new tetranuclear complexes of macrocyclic oxamide [Cd(CuL)3](NO3)2·2.5H2O 1, [Mn(CuL)3(OH)2](ClO4)2·Mn(H2O)6·4.5H2O 2 (L = 1,4,8,11-tatraazacyclotradecanne-2,3-dione) have been synthesized, structurally characterized and preliminary investigated
by magnetic studies. The structures of the title complexes consist of a tetranuclear units MCu3 (M = Cd, Mn), the packing diagram shows two-dimensional and three-dimensional system through intermolecular weak interactions.
The temperature-dependent magnetic susceptibilities of complex 2 were analyzed by an approximate treatment leading to J = −33 cm−1, gCu = 2.10, gMn = 1.95 indicating antiferromagnetic exchange between Cu(II) and Mn(II) ions. 相似文献
77.
Yanli Zeng Lingpeng Meng Shijun Zheng Maofa Ge Dianxun Wang 《Chemical physics letters》2004,400(4-6):394-400
A cluster DFT (B3LYP) calculation study of ClN3 and BrN3 dissociation pathways catalyzed by molecular sieve is reported. A three-tetrahedral molecular sieve cluster (Al(OHSiH3)(OSiH3)(OH)2, called T3) has been chosen in this study. Triplet-state products ClN and BrN are more easily produced with T3 molecular sieve cluster. Although the potential energy surfaces with T3 molecular sieve cluster are similar with those without T3 molecular sieve cluster, the dissociation process of ClN3 and BrN3 with T3 molecular sieve cluster becomes easier, which can be attributed to smaller energy gaps from the ground state reactant to the intersystem crossing point. 相似文献
78.
An enantiospecific synthesis of Schinzer's ketone 3 from (R)-(+)-pulegone via alpha-carbonyl radical cyclization was accomplished. This work also constitutes an enantiospecific formal syntheses of (-)-pinguisenol and (-)-alpha-pinguisene. The intermediate ketone 4 would be useful for the synthesis of other pinguisane-type sesquiterpenes. 相似文献
79.
This
study discussed the phenomena on thermal polymerization of α-methylstyrene
(AMS). A curve scanned by temperature-programmed technique was performed by
differential scanning calorimetry (DSC). Heat of polymerization (ΔH) and onset temperature of exothermic (T0) behavior were determined
to be 280±10 J g-1 and about 138±1°C,
respectively. A dimer formation mechanism was proposed for initiation of the
propagating chain. Spectroscopic identification of dimer structure was conducted
by infrared (IR) spectroscopy in the wavenumber from 650 to 1100 cm-1associated
with molecular fingerprint characteristics. The mechanism of thermal polymerization
on α-methylstyrene proposed in this study was similar to that of styrene
suggested by Mayo. 相似文献
80.