MICROCHIMICA ACTA
·
2017
·Vol. 184
·期 7
·2227-2239
·
IF 4.58
Li Cheuk-Wing,Zhu Yan,Zhan Jinsheng,Ma Junping,Gu Longjun,Fang Yaning,Yi Changqing
It is known for hydrophobic small molecules and proteins to be strongly adsorbed on the surface of polydimethylsiloxane (PDMS) based microdevices. However, no systematic studies have addressed issues related to the sorption of nanoparticles (NPs) on PDMS surfaces. The authors have used carboxylate-modified polystyrene nanoparticles (PS NPs), with sizes of <100 nm and prepared in different curing agent ratios, to study their sorption by native PDMS of different brands. It is found that both dynamic coating with sodium dodecyl sulfate and sol-gel modification can relieve the sorption issues, but only the co-treatment with both species gives satisfactory results in terms of suppressing bulk absorption. This combined coating strategy was further testified by an on-chip separation of a mixture of PS NPs (of 20 nm, 50 nm and 500 nm average diameter) based on a linear node array with enhanced mixing and diffusion-biased recovery of smaller nanoparticles. Instead of changing device design, optimal parameters for nano-separation can be achieved by changing the flow rate between a pair of syringe pumps. A more than 10-fold enrichment of 20 nm NPs was obtained when analyzing a mixture of nanoparticles. Since PDMS is still the preferred choice as a microfluidic substrate, this combined coating strategy is perceived to be highly beneficial in on-chip nano-separation and nanosynthesis using PDMS based microdevices.
With combined titania and sodium dodecyl sulfate inner coating of a PDMS microdevice, more than 10 fold enrichment of 20 nm NPs was accomplished when analyzing a mixture of 20 nm, 50 nm and 500 nm nanoparticles by changing the flow rate between a pair of syringe pumps.
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ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2017
·Vol. 24
·期 12
·11549-11558
·
IF 2.741
Zhou Lei,Zhang Ya,Ying Rongrong,Wang Guoqing,Long Tao,Li Jianhua,Lin Yusuo
The widespread occurrence of organophosphorus pesticides (OPPs) in the environment poses risks to both ecologic system as well as human health. This study investigated the oxidation kinetics of chlorpyrifos (CP), one of the typical OPPs, by thermoactivated persulfate (PS) oxidation process, and evaluated the influence of key kinetic factors, such as PS concentrations, pH, temperature, bicarbonate, and chloride ions. The reaction pathways and mechanisms were also proposed based on products identification by LC-MS techniques. Our results revealed that increasing initial PS concentration and temperature favored the decomposition of CP, whereas the oxidation efficiency was not affected by pH change ranging from 3 to 11. Bicarbonate was found to play a detrimental role on CP removal rates, while chloride showed no effect. The oxidation pathways including initial oxidation of P=S bond to P=O, dechlorination, dealkylation, and the dechlorination-hydroxylation were proposed, and the detailed underlying mechanisms were also discussed. Molecular orbital (MO) calculations indicated that P=S bond was the most favored oxidation site of the molecule. The toxicity of reaction solution was believed to increase due to the formation of products with P=O structures. This work demonstrates that OPPs can readily react with SO 4
·− and provides important information for further research on the oxidation of these contaminants.
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ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2017
·Vol. 409
·期 8
·2239-2246
·
IF 3.431
Zhang Jie,Zhang Tiehua,Guan Tianzhu,Yu Hansong,Li Tiezhu
Widespread use of bisphenol A (BPA) and other bisphenol analogues has attracted increasing attention for their potential adverse effects. As environmental endocrine-disrupting compounds (EDCs), bisphenols (BPs) may activate a variety of nuclear receptors, including glucocorticoid receptor (GR). In this work, the binding of 11 BPs to GR was investigated by fluorescence polarization (FP) assay in combination with molecular dynamics simulations. The human glucocorticoid receptor was prepared as a soluble recombinant protein. A fluorescein-labeled dexamethasone derivative (Dex-fl) was employed as tracer. Competitive displacement of Dex-fl from GR by BPs showed that the binding affinities of bisphenol analogues were largely dependent on their characteristic functional groups. In order to further understand the relationship between BPs structures and their GR-mediated activities, molecular docking was utilized to explore the binding modes at the atomic level. The results confirmed that structural variations of bisphenol analogues contributed to different interactions of BPs with GR, potentially causing distinct toxic effects. Comparison of the calculated binding energies vs. experimental binding affinities yielded a good correlation ( R
2 = 0.8266), which might be helpful for the design of environmentally benign materials with reduced toxicities. In addition, the established FP assay based on GR exhibited the potential to offer an alternative to traditional methods for the detection of bisphenols.
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CELLULOSE
·
2017
·Vol. 24
·期 3
·1383-1394
·
IF 3.417
Wang Kui,Ye Jun,Zhou Minghao,Liu Peng,Liang Xinyu,Xu Junming,Jiang Jianchun
Direct conversion of cellulose into levulinic acid and furfural in sulfolane media with the aid of water and H 2 SO 4 was performed at 140–220 °C under the pressures of 0–1.5 MPa. This approach could obtain 72.5 mol% levulinic acid and 11.5 mol% furfural formation under an optimal condition in which the mass ratio of sulfolane, water and H 2 SO 4 was 90:10:1. It was found that the decrease of water content led to an increasing yield of furfural and that the maximum furfural yield (51.1 mol%) could be obtained in the absence of water. The synergism of sulfolane and water in the selective liquefied system was demonstrated to be responsible for not only reinforced effect of optimizing and isolating the target products but also for reducing re-polymerization and side reactions. Furthermore, sulfolane in our case could be recycled and re-used for the conversion of cellulose with the same yield, which shed light on the remarkable potential for future industrial application.
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EUROPEAN FOOD RESEARCH AND TECHNOLOGY
·
2016
·Vol. 243
·期 2
·203-214
·
IF 1.433
Liu Tao,Zhu Wei,Huang Jing,Chen Huahan,Nie Rongzu,Li Chun-mei
The influence of the planting season on the nutritional as well as the aromatic composition of Hezuo 903 tomato was investigated by combining use of nutrition analysis, sensory evaluation, electronic nose and electronic tongue analysis, gas chromatography–mass spectrometry (GC–MS) and GC–MS–olfactometry (GC–MS–O) method. The results suggested that in-season tomato contained higher levels of reducing sugar, vitamin C and lycopene than off-season tomato. In-season tomato showed a better overall flavor and acceptability than off-season tomato. Significant difference was observed in both composition and concentration of the typical volatile and aroma-active compounds in two samples. E-2-Hexenal and methyl salicylate were only found in off-season tomato, and phenylacetaldehyde detected merely in in-season tomato. In addition, significantly higher levels of 6-methyl-5-hepten-2-one ( P < 0.01) and 2-isobutylthiazole ( P < 0.01) were detected in off-season tomato than in-season tomato, which showed a negative effect on the overall flavor of tomato. Our result indicated that the planting season affected the composition and concentration of both non-volatile and volatile compounds of tomato fruit.
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JOURNAL OF SOLID STATE ELECTROCHEMISTRY
·
2017
·Vol. 21
·期 8
·2381-2391
·
IF 2.316
Wang Jiajia,Yin Haixia,Chen Jingshuai,Niu Helin,Mao Changjie,Song Jiming,Jin Baokang,Tian Yupeng,Zhang Shengyi
A hydrophilic polypyrrole/tellurium (PPy/Te) nanocomposite was synthesized by a facile approach in which H 2 TeO 3 was used as the oxidizing agent of pyrrole and then the elemental Te formed in situ catalyzed the polymerization of pyrrole. The morphology and structure of the products were characterized by a series of testing technology. The electrochemical property and impedance of the PPy/Te nanocomposite were studied by cyclic voltammetry and electrochemical impedance spectroscopy, respectively. Significantly, the charge-discharge measurement results show that the PPy/Te nanocomposite has high specific capacitance (2488 F/g, at 2 A/g) and good cyclability.
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APPLIED MICROBIOLOGY AND BIOTECHNOLOGY
·
2017
·Vol. 101
·期 13
·5325-5332
·
IF 3.42
Cao Hao,Nie Kaili,Li Chengcheng,Xu Haijun,Wang Fang,Tan Tianwei,Liu Luo
Adenosine-5′-triphosphate (ATP) is the energy equivalent of the living system. Polyphosphate (polyP) is the ancient energy storage equivalent of organisms. Polyphosphate kinases (PPKs) catalyze the polyP formation or ATP formation, to store energy or to regenerate ATP, respectively. However, most PPKs are active only in the presence of long polyPs, which are more difficult and more expensive to generate than the short polyPs. We investigated the PPK preference towards polyPs by site-directed mutagenesis and computational simulation, to understand the mechanism and further design enzymes for effective ATP regeneration using short polyPs for in vitro cascade reactions, which are highly desired for research and applications. The results suggest that the short polyPs inhibit PPK by blocking the ADP-binding pocket. Structural comparison between PPK ( Corynebacterium glutamicum ) and PPK ( Sinorhizobium meliloti ) indicates that three amino acid residues, i.e., lysine, glutamate, and threonine, are involved in the activity towards short polyP by fixing the adenosine group of ADP in between the subunits of the dimer, while the terminal phosphate group of ADP still offers an active site, which presents a binding pocket for ADP. A proposed triple mutant PPK (SMc02148-KET) demonstrates significant activity towards short polyP to form ATP from ADP. The obtained high glutathione titer (38.79 mM) and glucose-6-phosphate titer (87.35 mM) in cascade reactions with ATP regeneration using the triple mutant PPK (SMc02148-KET) reveal that the tailored PPK establishes the effective ATP regeneration system for ATP-dependent reactions.
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ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2017
·Vol. 409
·期 11
·2839-2846
·
IF 3.431
Wang Chengke,Wang Chengen,Wang Qingqing,Chen Dan
In this paper, a resonance light scattering (RLS) method was developed for detecting kanamycin with high sensitivity and selectivity. Here, aptamer specific to kanamycin was utilized for recognizing and competitively binding with kanamycin, and gold nanoparticles (GNPs) were used as probes. After adding kanamycin into solutions containing aptamer and GNPs, the GNPs would aggregate in the presence of NaCl, which resulted in the RLS signal intensities enhanced dramatically. Based on this phenomenon, kanamycin can be detected in the range of 10 to 600 nM with a limit of detection as 1 nM, which is more sensitive than many other instrumental methods, especially the commonly used UV-visible spectroscopic method. Furthermore, we demonstrated that this method can be used for detecting kanamycin in milk samples with satisfactory results, which is meaningful for solving food safety problems.
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JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2016
·Vol. 28
·期 6
·4684-4689
·
IF 1.798
Li Zheng,Zhang Le,Zhou Tianyuan,Wang Lixi,Wong Ching Ping,Yang Hao,Zhang Qitu
A novel spray co-precipitation method was adopted to synthesize well dispersed nanocrystalline Y 2 O 3 powders for transparent ceramics. Several analytic techniques such as XRD, SEM, BET and UV–Vis–NIR spectrophotometer were used to determine the properties of coprecipitated powders, and the microstructure and optical properties of as-fabricated ceramics. The influences of the aging time on powders and ceramics were systematically investigated. Precursors were completely reached to yield the Y 2 O 3 phase after being calcined at 1250 °C in air. The calcined Y 2 O 3 powders exhibited an approximately spherical morphology with narrow size distribution and weak agglomeration, with mean particle size of ~140 nm. The co-precipitated nanopowders with an aging time of 12 h exhibited the best sintering activity due to the low agglomeration, and the in-line transmittance of Y 2 O 3 ceramic sintered at 1800 °C for 8 h in vacuum reached to 77.2% at 1064 nm (1 mm thickness).
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POLYMER BULLETIN
·
2016
·Vol. 74
·期 4
·1061-1076
·
IF 1.371
Yong Qiwen,Nian Fuwei,Liao Bing,Guo Ying,Huang Liping,Wang Lu,Pang Hao
Self-matt coating of waterborne polyurethane (WBPU) was synthesized by combining prepolymer and self-emulsification methods. The emulsion was fabricated from both hydroxy carboxylic acid and aminosulfonic acid types of hydrophilic chain-extending agents, in which the 2-[(2-aminoethyl) amino] ethane sulphonate sodium (AAS salt) was produced in laboratory. This emulsion demonstrated an excellent matt performance without the addition of extra matting agents after filming. Four different kinds of surface properties were measured on the film: the specular gloss (60° gloss meter), the contact angle (CA), the surface roughness degree (3D Surface Profilometer), and the topography of the coatings surface (SEM). The results showed that tons of spherical particles with diameter in a few micrometers were aggregated on the film surface. The effect of the roughness parameters ( R
a
and R
q
) and the average particle size of the emulsions on the specular gloss degree were probed. The research indicated that the emulsion with average particle size in the range of 2.5–3.0 µm and, meanwhile, the film with roughness parameters R
a
and R
q
both greater than 1 µm could attain the best matt effect. The WBPU emulsions showed good physical and mechanical properties, and were introduced into wood varnish for matting purpose.
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JOURNAL OF POROUS MATERIALS
·
2016
·Vol. 24
·期 1
·45-54
·
IF 1.385
Ma Jing,Xu Shangyuan,Chu Jia,Xue Juanqin,Tang Jieli,Qiang Liangsheng
In this paper, a series of metal supported TiO 2 /SBA-16 photocatalysts were successfully synthesized by wet impregnation method. The synthesized samples were characterized by X-ray diffraction (XRD), Raman spectra, N 2 adsorption–desorption, transmission electron microscopy (TEM), UV–visible absorption spectra (UV-vis) and X-ray photoelectron spectroscopy (XPS). It was found that SBA-16 retained the ordered mesostructure after modification. The results shown that loading different metal elements was found to have significant influences on the crystallographic structure and physical properties. Moreover, the prepared materials were evaluated on photodegradation of Rhodamine B (RhB). Experiment results showed that the degradation of RhB by these catalysts follows the pseudo-first-order kinetic model. The effect of metal element on photocatalytic activity can be attributed that the appropriate amounts of metal concentration can enhance the photocurrent due to the reduced electron–hole recombination, which can improve the efficiency of photocatalytic reactions.
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BMC Complementary and Alternative Medicine
·
2017
·Vol. 17
·期 1
·1-10
·
IF 2.288
Chen Long,Liu Tianjun,Wang Qiangsong,Liu Juan
Background Resveratrol and curcumin, as natural flavones products, have good therapeutic effect in acute and chronic inflammation; on the other hand, tetramethylpyrazine (TMP) has angiogenesis and vessel protection effect as well as anti-inflammatory function. In this paper, the anti-inflammatory effect of the tetramethylpyrazine, resveratrol and curcumin (TRC) combination in acute and chronic inflammation was reported in vivo.Methods The dose of the combined three natural products was optimized based on the acute paw swelling mouse model with a Uniform Design methodology. The therapeutic effect of TRC combination on chronic inflammation was investigated by using the collagen-induced arthritis (CIA) rat model based upon the following indexes: the volume of paw swelling, arthritis score, serum mediators and histological examination as well as immunohistochemical staining. The levels of alanine aminotransferase (ALT) and aspartate transaminase (AST) in serum were measured and the pathological sections of liver and kidney were analysed. LD50 was measured based on the acute oral toxicity (AOT) standard method.Results The best formulation was the three components combined at the same mass proportion revealed by the Uniform Design methodology. This combination could significantly reduce the paw swelling in acute paw swelling mouse model, could reduce paw swelling and alleviate the damage in joint structural of ankle, cartilages and fibrous tissue in CIA rat model. The dose relationship was clear in both cases. Immunohistochemical staining of ankle tissue revealed that TRC combination was able to inhibit the expression of NF-κB p65 and TNF-α which were closely related to the inflammatory process. Analysis of serum mediators revealed TRC combination could inhibit the production of TNF-α, IL-1β, and IL-6 in the serum. Toxic study revealed this formulation was low toxic, LD50 was larger than 5 g/kg, both the level of ALT and AST and histopathology in the liver and kidney exhibited no distinctions between the TRC combination and the blank group, no mortality occurred at the administered doses of 5 g/kg.Conclusion sThe results showed this formulation could provide a novel potent treatment for acute and chronic inflammation (RA) without side effect like gastric injury occurring in NSAIDs.
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