POLYMER BULLETIN
·
2015
·Vol. 72
·期 11
·2949-2965
·
IF 1.438
Ren Qiang,Xiang Yanli,Huang Chunyan,Li Jian,Wang Chengyi
A novel epoxy resin toughener based on star-shaped copolymer of butyl acrylate (BA) and glycidyl methacrylate (GMA) [poly (BA- co -GMA)] with low viscosity was developed. The star polymers were synthesized by initiators for continuous activator regeneration atom transfer radical polymerization (ICAR ATRP) using tri, tetra and hexa-functional initiators. The branching parameters of star poly (BA- co -GMA) were characterized by gel permeation chromatography with a laser light scattering-viscometry triple detection system. Copolymer composition and glass transition temperatures of the copolymers were analyzed by proton nuclear magnetic resonance ( 1 H-NMR) and differential scanning calorimetry (DSC), respectively. The results showed that the branching ratio decreased as the number of arms increased. The epoxide groups of the GMA units were kept intact during ICAR ATRP. Rheological, mechanical tests and dynamic mechanical analysis revealed that star poly (BA- co -GMA)/diglycidyl ether of bisphenol A (DGEBA) epoxy resin formulation exhibited better processability, higher impact resistance and thermal resistance than those of linear poly (BA- co -GMA)/DGEBA epoxy resin formulation.
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EUROPEAN JOURNAL OF PLANT PATHOLOGY
·
2015
·Vol. 142
·期 3
·547-556
·
IF 1.49
Luo Zaiqi,Guo Huili,Yang Yadong,Yang Mingfen,Ma Lanqin,Wang Younian
Huping jujube is widely cultivated in northern China. PcPKS5, a resveratrol synthase (STS) gene, contains all functionally divergent plant specific type III PKSs and is involved in resveratrol synthesis. This study aimed to assess the effects of heterologous overexpression of the resveratrol synthase (PcPKS5) gene on Huping jujube (Ziziphus jujuba Mill.) plant resistance and nutritional quality. Stems with leaves and shoot tips of Huping jujube (Ziziphus jujuba Mill) were infected with agrobacterium expressing PcPKS5 and GUS, and three positive plants were identified. Resveratrol (0.45 μg/g fresh weight) was detected by HPLC in line 2 transgenic plants. Interestingly, 100 μl extract of 1 g/ml transgenic plant crude extract showed an inhibitory effect equivalent to 1.0 μg of pure resveratrol. In addition, transgenic plants displayed increased anti-mite resistance compared with the wild-type counterparts. Importantly, higher PcPKS5 expression levels were found in young tissues compared with the stem and mature leaves. This study also provides a stable genetic transformation mechanism for developing new plant germplasms in Huping jujube.
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JOURNAL OF POLYMER RESEARCH
·
2015
·Vol. 22
·期 4
·1-8
·
IF 1.92
Cheng Chuanjie,Bai Xiongxiong,Zhang Xu,Li Hongxia,Huang Qinghua,Tu Yuanming
A symmetric photo-active trithiocarbonate was designed and synthesized, which can act not only as a functional reversible addition-fragmentation chain transfer (RAFT) agent, but also as a crosslinker in crosslinking poly(methyl methacrylate- co -hydroxy ethyl acrylate) (poly(MMA- co -HEA)) due to interactions of benzophenone moieties of trithiocarbonate and hydroxyl groups of poly(MMA- co -HEA) under UV irradiation. In addition, the crosslinked poly(MMA- co -HEA) demonstrates photo-promoted self-healing properties by reshuffling C-S bonds of trithiocarbonate.
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POLYMER BULLETIN
·
2014
·Vol. 71
·期 11
·2981-2997
·
IF 1.491
Li Mei,Li Gu,Fan Yifei,Jiang Juan,Ding Qian,Dai Xin,Mai Kancheng
To improve the photo-oxidation degradation resistance and antimicrobial ability of ZnO-filled polypropylene random copolymer (PPR), 13X zeolite particles supported with nano-ZnO with different morphologies were prepared and used to manufacture filled PPR composites. The formation of ZnO with different morphologies on the surface of 13X zeolite was proved by atomic absorption spectroscopy, scanning electron microscope, UV–vis spectra, and fluorescence spectra. The results indicated that the photo-oxidation degradation resistance of nano-ZnO-supported 13X zeolite-filled PPR composites is higher than that of PPR composites filled by the same content of pure nano-ZnO. Antimicrobial experiment results show that nano-ZnO-supported 13X zeolite-filled PPR composites exhibit higher antimicrobial properties than ZnO-filled PPR composites prepared by directly adding nano-ZnO into PPR matrix for Staphylococcus aureus and Escherichia coli . The addition of nano-ZnO-supported 13X zeolite particles increases the crystallization temperature, but has no influence on the melting behavior of PPR composites.
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ECOTOXICOLOGY
·
2014
·Vol. 24
·期 1
·19-28
·
IF 2.5
Zhang Dawen,Liao Qiegen,Zhang Li,Wang Donggen,Luo Linguang,Chen Yuwei,Zhong Jiayou,Liu Jutao
Occurrence and spatial distributions of microcystins (MCs; MC-RR, -YR, -LR, -LA, -LF, -LW) in Poyang Lake were studied during the period from July 6 to July 18, 2012, by using ultra-high-performance liquid chromatography–electrospray ionization tandem triple quadrupole/mass spectrometry (UPLC-MS/MS). MC-RR was the most dominant variant (94.70 and 84.73 % for intracellular (cellular MCs) and extracellular (dissolved MCs) MCs, respectively) in Poyang Lake, followed by MC-LR (4.65 and 13.17 %, respectively), MC-YR (0.8 and 2.63 %, respectively), and MC-LA (0.02 and 0.00 %), while MC-LW and MC-LF were not detected. Total MCs concentrations (intracellular +extracellular MCs) ranged between 0.0036 and 7.97 μg/L, with an average of 0.79 μg/L, and only two sampling stations with the total MCs concentrations exceeded the drinking water guideline level of 1 μg/L for MC-LR proposed by World Health Organization. The overall spatial pattern of intracellular and extracellular MCs in Poyang Lake demonstrates decreasing trends from east to west, and the south part higher than the north part. Intracellular MCs content was negatively correlated with total nitrogen (r = −0.34, p < 0.01) and NO 3 (r = −0.35, p < 0.01), while no significant correlation was found between intracellular MCs concentration and total phosphorus, NH 4 , and NO 2 ( p > 0.05), suggesting that NO 3 might be a regulating factor for MCs production in Poyang Lake. In addition, intracellular MCs concentrations were positively correlated with wind speed, Microcystis and Cyanobacteria biomass (r = 0.34–0.51, p < 0.05), indicating that wind speed plays an important role in the spatial distributions of MCs, and NO 3 , toxic cyanobacteria (mainly Microcystis ), and wind speed seem to be the important forcing factors driving MCs spatial distributions in Poyang Lake.
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高影响因子
MICROCHIMICA ACTA
·
2014
·Vol. 181
·期 13
·1497-1503
·
IF 3.719
Su Shao,Sun Haofan,Xu Fei,Yuwen Lihui,Fan Chunhai,Wang Lianhui
An electrochemical glucose biosensor was developed by immobilizing glucose oxidase (GOx) on a glass carbon electrode that was modified with molybdenum disulfide (MoS 2 ) nanosheets that were decorated with gold nanoparticles (AuNPs). The electrochemical performance of the modified electrode was investigated by cyclic voltammetry, and it is found that use of the AuNPs-decorated MoS 2 nanocomposite accelerates the electron transfer from electrode to the immobilized enzyme. This enables the direct electrochemistry of GOx without any electron mediator. The synergistic effect the MoS 2 nanosheets and the AuNPs result in excellent electrocatalytic activity. Glucose can be detected in the concentration range from 10 to 300 μM, and down to levels as low as 2.8 μM. The biosensor also displays good reproducibility and long-term stability, suggesting that it represents a promising tool for biological assays.
A MoS 2 -based glucose sensor has been prepared by gold nanoparticles-decorated MoS 2 nanocomposite, which exhibited excellent electrocatalytic activity, reproducibility and long-term stability. It was applied to determine glucose concentration in human serum, suggest the sensor maybe promising for practical application.
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ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2014
·Vol. 406
·期 7
·1903-1908
·
IF 3.578
Qian Sihua,Lin Hengwei
A simple, inexpensive yet highly selective colorimetric indicator-displacement assay array for the simultaneous detection and identification of three important biothiols at micromolar concentrations under physiological conditions and in real samples has been developed in this work. With use of an array composed of metal indicators and metal ions, clear differentiation among cysteine, homocysteine and glutathione was achieved. On the basis of the colour change of the array, quantification of each analyte was accomplished easily, and different biothiols were identified readily using standard chemometric approaches (hierarchical clustering analysis). Moreover, the colorimetric sensor array was not responsive to changes with 19 other natural amino acids, and it showed excellent reproducibility. Importantly, the sensor array developed was successfully applied to the determination and identification of the three biothiols in a real biological sample.
A simple, inexpensive yet highly selective colorimetric indicator-displacement assay array for the simultaneous detection and identification of three important biothiols was developed in this work
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COLLOID AND POLYMER SCIENCE
·
2014
·Vol. 292
·期 5
·1061-1072
·
IF 2.41
Luo Yan-Ling,Yang Xiao-Li,Xu Feng,Chen Ya-Shao,Zhao Xu
pH-sensitive poly(methacrylic acid)- block -hydroxyl-terminated polybutadiene- block -poly(methacrylic acid) block copolymers were synthesized by atom transfer radical polymerization of t -butyl methacrylate and follow-up acidolysis. The copolymers can spontaneously assemble into stable and nearly spherical micelle aggregates in aqueous solution, with hydrodynamic diameters ( D
h
) from 51 to 92 nm and critical micelle concentration of 3.90–7.76 mg L −1 . Z eta potentials were found to be increased with increasing (monomer)/(initiator) molar ratios. A pH-dependent phase behavior is produced at approximately 5.4–5.6, as determined by D
h
and I
335 / I
332 fluorescence intensity ratios. The in vitro camptothecin (CPT) release was compositional and pH dependent, and the cumulative CPT release below pH 7.2 was higher than that in pH 7.4. They could inhibit the premature burst CPT release. The copolymer micelles were low in cytotoxicity even at a micellar concentration of 800 mg L −1 , and therefore they may be used as potential drug-delivery carriers.
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Food Analytical Methods
·
2014
·Vol. 7
·期 8
·1693-1702
·
IF 1.802
Yang Jinling,Li Yongxin,Gong Weilei,Wang Changqin,Liu Bencheng,Sun Chengjun
A novel microextraction method termed matrix liquid-phase dispersion extraction (MLPDE) was presented in this paper. This method was adopted for the extraction of preservatives including methylparaben, ethylparaben, propylparaben, butylparaben, isopropylparaben, and isobutylparaben from different solid food samples. The extracted analytes were subjected to high-performance liquid chromatography (HPLC) analysis immediately. In this method, the food sample (0.50 g) was added previously to a syringe and then rinsed with hot water (45 °C). Subsequently, 2 ml extraction solvent (methanol) was added into the syringe. After ultrasonic extraction, food sample was dispersed into the methanol phase and a cloudy suspension came into being. Under the pressure of the plunger, methanol carrying the target analytes passed through 0.45 μm membrane and 10.0 μl of the eluent was injected into HPLC system. The important parameters including temperature, pH and volume of water, extraction solvent and its volume, sodium chloride addition, sample weight, and ultrasonic time as well as matrix effect were investigated. Under the optimum conditions, recoveries of the studied preservatives ranged from 93.7 % to 107.9 %. The intra-day and inter-day precisions (relative standard deviations) were less than 5.16 % and 5.32 %, respectively. The linear ranges of the method were 0.947–400 mg/kg with the correlation coefficients of 0.9988 to 0.9999. The limits of detection were 0.285 to 1.122 mg/kg. MLPDE is a very simple, rapid, cheap, and efficient method for extraction of nonpolar organic compounds from solid food samples. The proposed method has been successfully applied to the separation and quantification of six parabens in different solid food samples.
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Nanoscale Research Letters
·
2014
·Vol. 9
·期 1
·1-8
·
IF 2.481
Song Yuan-Jun,Wang Mingliang,Zhang Xiao-Yang,Wu Jing-Yuan,Zhang Tong
Serving as shape control agent, polyvinyl pyrrolidone (PVP) has been widely used in chemical synthesis of metal nanoparticles. However, the role of molecular weight (MW) of PVP has been rarely concerned. In this study, we show a facile method to control the shapes of silver nanocrystals using PVP with different MWs. PVP MW=8,000 , PVP MW=29,000 , PVP MW=40,000 , and PVP MW=1,300,000 are compared in the present study. Surprisingly, high-yield silver rodlike nanostructures, nanospheres, and nanowires can be obtained under the same growth environment and reactant concentrations by simply changing the MW of PVP. The mechanism studies of the role of PVP with different MWs in the growth process were carried out systemically using the morphology and spectroscopic measurement, FT-IR spectrum analysis, and seed crystallization monitoring. The results indicate that the MW of PVP plays a determinant role in the morphology and optical property control of the silver nanocrystals. Meantime, the concentration of PVP was found to be an assistant factor to further improve the shape and the yield of the synthesized nanocrystals.
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ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2014
·Vol. 21
·期 7
·5217-5226
·
IF 2.757
Peng Na,Wang Kaifeng,Liu Guoguang,Li Fuhua,Yao Kun,Lv Wenying
Beta blockers are widely used pharmaceuticals that have been detected in the environment. Interactions between beta blockers and dissolved organic matter (DOM) may mutually alter their environmental behaviors. To assess this potential, propranolol (PRO) was used as a model beta blocker to quantify the complexation with DOM from different sources using the fluorescence quenching titration method. The sources of studied DOM samples were identified by excitation–emission matrix spectroscopy (EEMs) combined with fluorescence regional integration analysis. The results show that PRO intrinsic fluorescence was statically quenched by DOM addition. The resulting binding constants (log K
oc ) ranged from 3.90 to 5.20, with the surface-water-filtered DOM samples claiming the lower log K
oc and HA having the highest log K
oc . Log K
oc is negatively correlated with the fluorescence index, biological index, and the percent fluorescence response ( P
i ,n ) of protein-like region ( P
I,n ) and the P
i ,n of microbial byproduct-like region ( P
II,n ) of DOM EEMs, while it is correlated positively with humification index and the P
i ,n of UVC humic-like region ( P
III,n ). These results indicate that DOM samples from allochthonous materials rich in aromatic and humic-like components would strongly bind PRO in aquatic systems, and autochthonous DOM containing high protein-like components would bind PRO more weakly.
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AAPS Journal
·
2013
·Vol. 16
·期 1
·101-113
·
IF 4.386
Qiao Xue,Ji Shuai,Yu Si-wang,Lin Xiong-hao,Jin Hong-wei,Duan Yao-kai,Zhang Liang-ren,Guo De-an,Ye Min
Licorice has been shown to affect the activities of several cytochrome P450 enzymes. This study aims to identify the key constituents in licorice which may affect these activities. Bioactivity assay was combined with metabolic profiling to identify these compounds in several complex licorice extracts. Firstly, the inhibition potencies of 40 pure licorice compounds were tested using an liquid chromatography/tandem mass spectrometry cocktail method. Significant inhibitors of human P450 isozymes 1A2, 2C9, 2C19, 2D6, and 3A4 were then selected for examination of their structural features by molecular docking to determine their molecular interaction with several P450 isozymes. Based on the present in vitro inhibition findings, along with our previous in vivo metabolic studies and the prevalence of individual compounds in licorice extract, we identified several licorice constituents, viz ., liquiritigenin, isoliquiritigenin, together with seven isoprenylated flavonoids and arylcoumarins, which could be key components responsible for the herb–drug interaction between cytochrome P450 and licorice. In addition, hydrophilic flavonoid glycosides and saponins may be converted into these P450 inhibitors in vivo . These studies represent a comprehensive examination of the potential effects of licorice components on the metabolic activities of P450 enzymes.
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