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211.
212.
213.
A series of luminescent PAMAM dendrons emanating from 8-hydroxyquinoline have been synthesized and their coordination with Zn(II) was investigated for the first time. The obtained dendritic Zn(II) complexes were soluble in common organic solvents. It was found that the luminescence intensity of G2 dendron 6 was higher than that of G1 dendron 4. Furthermore, when they were coordinated with Zn(II), red-shift was observed and the intensities of the coordinated Zn(II) complexes were higher than that of the corresponding ligands. 相似文献
214.
215.
This paper describes an improved scheme for the identification of antigens in crude extracts recognized by specific antibodies when analyzed by a combination of two-dimensional gel electrophoresis and immunoblotting. First, protein components in gels are electrophoretically transferred to a polyvinylidene difluoride membrane which does not shrink or change dimensions in organic solvents. The efficiency of transfer and the localization of sample proteins on the membrane are checked and recorded by staining the blotting membrane with Fast Green FCF and recording the profile on a transparency. After blocking and the immunoassay, the results are recorded by photography. The sites of immune reaction are marked and the same membrane is restained briefly with Coomassie Brilliant Blue R-250 for the protein profile. Thus antigens in complex mixtures, recognized by antibodies of interest, can easily be identified from the restained membrane. If the whole protein profile is not well demonstrated, when used in combination with the profile recorded on the transparency, spots appearing on the restained membrane can still be used as useful landmarks in the final unequivocal antigenic identification. This improved scheme circumvents problems arising from membrane shrinkage and difficulties in accurately matching immunoreactive spots by conventional procedures and thus provides an accurate, simple and fast approach in the identification of antigens after immunoblotting. 相似文献
216.
Mingzuo Shen 《International journal of quantum chemistry》1990,38(4):551-557
R. A. Davidson's rules for splitting an n-fold rotationally symmetric graph can be derived from a unitary transformation on the adjacency matrix. The McClelland and D'Amato rules are special cases with n = 2 and n = 3, respectively. 相似文献
217.
The influence of introducing water molecules into a cation-pi complex on the interaction between the cation and the pi system was investigated using the MP2/6-311++G method to explore how a cation-pi complex changes in terms of both its geometry and its binding strength during the hydration. The calculation on the methylammonium-benzene complex showed that the cation-pi interaction is weakened by introducing H(2)O molecules into the system. For example, the optimized interaction distance between the cation and the benzene becomes longer and longer, the transferred charge between them becomes less and less, and the cation-pi binding strength becomes weaker and weaker as the water molecule is introduced one by one. Furthermore, the introduction of the third water molecule leads to a dramatic change in both the complex geometry and the binding energy, resulting in the destruction of the cation-pi interaction. The decomposition on the binding energy shows that the influence is mostly brought out through the electrostatic and induction interactions. This study also demonstrated that the basis set superposition error, thermal energy, and zero-point vibrational energy are significant and needed to be corrected for accurately predicting the binding strength in a hydrated cation-pi complex at the MP2/6-311++G level. Therefore, the results are helpful to better understand the role of water molecules in some biological processes involving cation-pi interactions. 相似文献
218.
The synthesis of norvancomycin (NVan)-capped silver nanoparticles (Ag@NVan) and their notable in vitro antibacterial activities against E. coli, a Gram-negative bacterial strain (GNB), are reported here. Mercaptoacetic acid-stabilized spherical silver nanoparticles
with a diameter of 16±4 nm are prepared by a simple chemical reaction. The formation process of the silver nanoparticles is
investigated by UV-visible (UV-vis) spectroscopy and transmission electron microscopy (TEM). NVan is then grafted to the terminal
carboxyl of the mercaptoacetic acid in the presence of N-(3-Dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (EDAC). The TEM images of single bacteria treated with Ag@NVan show that plenty of Ag@NVan
aggregate in the cell wall of E. coli. A possible antibacterial mechanism is proposed that silver nanoparticles may help destroy the stability of the outer membrane
of E. coli, which makes NVan easier to bind to the nether part of the peptidoglycan structure. The antibacterial activities of silver
nanoparticles on their own, together with the rigid polyvalent interaction between Ag@NVan and cell wall, enables Ag@NVan
to be an effective inhibitor of GNB. This kind of bionanocomposites might be used as novel bactericidal materials and we also
provide an effective synthesis method for preparing functional bioconjugated nanoparticles here.
Supported by the National Natural Science Foundation of China (Grant No. 50373036) and Fok Ying Tung Education Foundation
(Grant No. J20040212) 相似文献
219.
Chun Chun ZHANG Wei ZENG Jian Zhang LI Sheng Ying QIN* Department of Chemistry Sichuan University Chengdu 《中国化学快报》2003,(6)
It is well known that the study on biomimetic oxygen carriers not only has important theoretic significance to discover the mechanism of reversible bonding, activating oxygen as well as the oxidation reaction in organism, but also has potential application in separating oxygen from air and realizing the high efficiency and selectivity of catalytic oxidation reaction under a mild condition1. Metal- porphyrin and metal- phthalol- gaunine have been extensively used as biomimetic oxygen carriers u… 相似文献
220.
Frederick MO Mulder JA Tracey MR Hsung RP Huang J Kurtz KC Shen L Douglas CJ 《Journal of the American Chemical Society》2003,125(9):2368-2369
A copper-catalyzed new C-N bond formation involving a sp-hybridized carbon is described here leading to a facile entry for syntheses of chiral ynamides. This direct N-alkynylation of amides should have a significant impact on the future development of synthetic methodologies employing ynamides. 相似文献