摘要：
The use of ester-terminated polyamidoamine dendrimers for stabilizing quantum dots in aqueous solutions, is analyzed. Quantum dots have many advantages in terms of optical properties, such as a narrow, tunable, symmetric emission and photochemical stability in comparison to traditional organic dyes. The key to develop quantum dots as a tool in biological systems is to achieve water solubility, biocompatibility, and photostability. The concentration of surfactant had an important effect on the size of the water soluble quantum-dots nanoparticles. The surface tension of the quantum dots nanoparticles decreased with increasing surfactant concentration. The surfactant could form a layer of hydrophilic film, which could prevent the aggregation of nanoparticles, protect the ester group against hydrolysis, and increase the stability of the quantum dots nanoparticles in aqueous media.
作者机构：
[Yu X.; Yang S.] Department of Chemistry and Environmental Engineering, Hubei Normal University, Huangshi, Hubei 435002, China;[Shaomin Shi] College of Chemistry, Central China Normal University, Wuhan, Hubei 430079, China
通讯机构：
[Shuijin Yang] D;Department of Chemistry and Environmental Engineering, Hubei Normal University, Huangshi, China
摘要：
A new environmentally friendly catalyst, H4SiW12O40-polyaniline (PAn), was prepared, and n-butyraldehyde 1,2-propanediol acetal was synthesized from n-butyraldehyde and 1,2-propanediol in the presence of H4SiW12O40-PAn. The influence factors of the synthesis were discussed, and the best reaction conditions were found: the molar ratio of n-butyraldehyde to 1,2-propanediol is 1:1.5, the amount of catalyst used is 1.2% of feed stock, and the reaction time is 1.0 h. H4SiW12O40-PAn is an excellent catalyst for synthesizing n-butyraldehyde 1,2-propanediol acetal, and the yield can reach more than 95.2%.
期刊：
JOURNAL OF AOAC INTERNATIONAL,2006年89(3):782-785 ISSN：1060-3271
通讯作者：
Lu Guanghan
作者机构：
[Lu Guanghan] Cent China Normal Univ, Coll Chem, Wuhan 430079, Peoples R China.;Yangtze Univ, Coll Chem & Environm Engn, Jinzhou 434023, Peoples R China.
通讯机构：
[Lu Guanghan] C;Cent China Normal Univ, Coll Chem, Wuhan 430079, Peoples R China.
摘要：
In KOH, the Mg(II)-bromopyrogallol red (BPR) complex produced a very sensitive polarographic wave at -1.30 V. The wave height was linear with the concentration of Mg(II) in the range of 0.05 to 2 microg/mL. The detection limit was 0.01 microg/mL. The electrochemical behavior of Mg(II)-BPR was studied by electrochemical and spectrophotometric methods. Experiments proved that the polarographic wave of Mg(II)-BPR was due to the reduction of BPR in the Mg(II)-BPR complex. The method, which was sensitive, selective, and simple to perform, was used to determine magnesium in foods, and the results were consistent with those obtained by atomic absorption spectroscopy.
作者机构：
[Lu, GH] Cent China Normal Univ, Coll Chem, Wuhan 430079, Peoples R China.;Yangtze Univ, Coll Chem & Environm Engn, Jinzhou 434100, Peoples R China.;Wuhan Univ, Coll Mol & Engn, Wuhan 430072, Peoples R China.
通讯机构：
[Lu, GH] C;Cent China Normal Univ, Coll Chem, Wuhan 430079, Peoples R China.
关键词：
Airborne fluoride;Fluoride analysis;Fluoride in vegetables;Hubei Province, China;Industrial fluoride pollution;Single-sweep polarography;Vegetables in China;Wuhan Iron and Steel Factory
摘要：
(E)-α-(Methoxyimino)-2-[1-(aryloxy)methyl] -benzeneacetates, the analogues of Kresoxim-methyl, were stereoselectively synthesized with the coupling reaction of 2-methylphenyldiazonium chloride and methyl 2-hydroxyiminoacetate in the presence of CuSO4/Na2SO3 as a key step, and it was first found that the coupling reaction could give the key intermediate material(E)- and(Z)-methyl 2-(hydroxyimino)-2-o-tolylacetate with a molar ratio of 14:1. The (E)-configurations of all these compounds were assigned on the basis of their 2D-NOESY spectra of 1H NMR. The preliminary bioassays indicate that most of the compounds show an activity against a wide variety of fungi.
作者机构：
[Liang, Pei; Chen, Xinmiao; Li, Yalan; Zhang, Taozhi] Cent China Normal Univ, Key Lab Pesticide & Chem Biol, Minist Educ, Wuhan 430079, Hubei, Peoples R China.
通讯机构：
[Zhang, Taozhi] C;Cent China Normal Univ, Key Lab Pesticide & Chem Biol, Minist Educ, Wuhan 430079, Hubei, Peoples R China.
关键词：
Gas chromatography-micro electron capture detector;Headspace liquid-phase microextraction;Volatile halocarbons
摘要：
The determination of four volatile halocarbons (CHCl3, CCl4, C2HCl3 and C2Cl4) in water by headspace liquid-phase microextraction (HS-LPME) with gas chromatography using a micro electron capture detector (GC-μECD) is described. The effects of the type and volume of the extraction solvent, headspace volume, stirring rate, extraction temperature and time and ionic strength on the extraction performance are investigated and optimized. The developed protocol yields a linear calibration curve in the concentration range from 0.05 to 50 µg L−1 for the target analytes; the detection limits ranged from 0.003 to 0.146 µg L−1 and the relative standard deviation (R.S.D.) values below 8.45%. The results demonstrate that HS-LPME followed with GC-μECD is a simple and reliable technique for the determination of volatile halocarbons in water samples.
期刊：
Journal of Pharmacy and Pharmaceutical Sciences,2006年9(2):238-244 ISSN：1482-1826
通讯作者：
Li, Songjun
作者机构：
[Li, Songjun; Shen, Yan; Hao, Xiao; Li, Wuke] Cent China Normal Univ, Coll Chem, Minist Educ, Key lab Pesticide & Chem Biol, Wuhan, Peoples R China.
通讯机构：
[Li, Songjun] C;Cent China Normal Univ, Coll Chem, Minist Educ, Key lab Pesticide & Chem Biol, Wuhan, Peoples R China.
摘要：
PURPOSE: The release of drug from a polymeric matrix is complicated. It often involves drug diffusion, interface movement and various interactions. It also shows a dependence on the length of polymer rod. With Lc as the 'critical length', three different phases can be distinguished from the kinetic process. Prior to reaching Lc, the interface movement plays a key role on determining the release. Otherwise, the drug diffusion can dominate the release process. Near Lc, however, both factors are involved. The rate of interface movement is closely associated with the time and position in the polymer rod. Taking these characters into account, a common model is presented in this article to be tentatively used to interpret the release process. These results provide preliminarily an insight into the understanding of controlled release process.
摘要：
Six topoisomers consisting of diethoxycarbonyl glycoluril have been successfully synthesized in one-pot by using a “figure-of-seven” building block through anti-connectivity and syn-connectivity reactions, respectively. The structures of all six topoisomers were first determined by X-ray crystallography. The finding that (±) CT isomers are the dominant products under thermodynamic control can be explained by the calculated relative energies of the six topoisomers. That the (±) CT isomers have the lowest energy is most likely due to the additional intramolecular electrostatic interactions between-NO2 and-OMe groups. The biological activities of the topoisomers were primitively investigated and the results of bioassay showed that the six topoisomers possessed obvious difference of herbicidal activity.
