JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY
·
2015
·Vol. 307
·期 1
·269-276
·
IF 1.034
Luo Bai-Cheng,Yuan Li-Yong,Chai Zhi-Fang,Shi Wei-Qun,Tang Quan
Metal–organic frameworks (MOFs) UiO-66 and its amine derivative (UiO-66-NH 2 ) with high surface area and unprecedented chemical stability were synthesized and first explored for U(VI) capture from aqueous solutions. At pH 5.5, U(VI) sorption reach equilibrium in ca. 4 h and the maximum sorption capacity is more than 100 mg g −1 . Moreover, they show desirable selectivity towards U(VI) over a range of competing metal ions. Sorption results demonstrate that introduction of amino groups into MOFs does not enhance U(VI) sorption, probably result from the lower activity of aromatic amines, decrease of surface area and formation of intermolecular hydrogen bonds.
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COLLOID AND POLYMER SCIENCE
·
2015
·Vol. 294
·期 3
·491-500
·
IF 1.865
Zhao Xiaohui,Liang Weiping,An Dong,Ye Zhiwen
Two tetrasiloxane Gemini imidazolium surfactants with methylene spacer groups ([Si 4 - s -Si 4 im]Cl 2 , s = 4, 6) were synthesized and characterized by 1 H NMR and ESI-MS spectrum. The surface activity and thermodynamic properties in aqueous solution among three categories of surfactants, including [Si 4 - s -Si 4 im]Cl 2 , the corresponding monomer ([Si 4 mim]Cl) and hydrocarbon-based Gemini imidazolium surfactant ([C 14 -4-C 14 im]Cl 2 ), were compared by surface tension and electrical conductivity methods. A series of surface activity parameters, including cmc, γ
cmc , π
cmc , pc 20 , Γ
max and A
min , and the adsorption isotherms were obtained from the surface tension plots. The results indicated that the tetrasiloxane Gemini imidazolium surfactant with the longer spacer group has the higher capacity to form micelles but lower efficiency to reduce surface tension. Besides, the cmc value of [Si 4 - s -Si 4 im]Cl 2 was about one order of magnitude lower than that of [Si 4 mim]Cl. The tetrasiloxane-based surfactants have the higher capacity to low the surface tension than the hydrocarbon-based surfactant. The adsorption isotherms of the tetrasiloxane-based surfactants are similar to those of conventional hydrocarbon-based surfactants. The thermodynamic parameters of micellization process, namely, the standard Gibbs free energy ( ΔG
m
θ ), enthalpy ( ΔH
m
θ ) and entropy ( ΔS
m
θ ) originated from the electrical conductivity measurements at five different temperatures, suggested that the micellization of [Si 4 - s -Si 4 im]Cl 2 and [C 14 -4-C 14 im]Cl 2 is entropy-driven process whereas aggregation of [Si 4 mim]Cl is enthalpy-driven process at the whole investigated temperatures. The dynamic light scattering results indicate that the aggregation size of [Si 4 -4-Si 4 im]Cl 2 (113.6 nm) is larger than [Si 4 -6-Si 4 im]Cl 2 (101.7 nm).
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JOURNAL OF MATERIALS SCIENCE
·
2015
·Vol. 51
·期 6
·3170-3181
·
IF 2.371
Wen Xin,Qiao Xianliang,Han Xue,Niu Libo,Huo Li,Bai Guoyi
Abstract A series of novel magnetic branched polyethylenimine nanogels (Fe 3 O 4 /bPEI) was prepared via the combination of crosslinking branched polyethylenimine to form a nanogel and in-situ generation of Fe 3 O 4 on its surface. Morphologies and magnetic properties of the Fe 3 O 4 /bPEI nanocomposites could be easily controlled by regulating the ratio between branched polyethylenimine nanogel and Fe 3 O 4 precursor. The nanocomposites could be applied as efficient and selective dye adsorbents for the removal of Congo red under different pH values or in the presence of methylene blue. Furthermore, it could also be applied as catalyst support for the loading of palladium to afford a novel Pd-Fe 3 O 4 /bPEI nanocomposite, which exhibited good catalytic activity in the reduction of nitrophenols using NaBH 4 as the reducing agent. Particularly, this nanocomposite could be easily separated by an external magnetic field and recycled ten times without appreciable loss of its initial catalytic activity. The synergistic integration of nanogel and magnetic Fe 3 O 4 nanoparticles makes Fe 3 O 4 /bPEI to be a versatile platform for multiple applications. Graphical Abstract Magnetically recyclable polyethylenimine nanogels (Fe 3 O 4 /bPEI), prepared with in-situ generated Fe 3 O 4 , can serve as excellent dye adsorbent and catalyst support.
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JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2015
·Vol. 27
·期 4
·3540-3548
·
IF 1.569
Zeng Jinfeng,Tian Xun,Song Jingsi,Wei Zhong,Harrington Steven,Yao Yagang,Ma Lei,Ma Yanqing
Here we report silver nanoparticles/reduced graphene oxide (AgNPs/rGO) nanocomposites were synthesized by a facile approach based on four green reductants using silver nitrate (AgNO 3 ) and graphene oxide (GO) as a precursor. Field Emission Scanning Electron Microscopy and High Resolution Transmission Electron Microscopy (HRTEM) have been employed to investigate morphological characteristics and exfoliation of reduced graphene oxide (rGO) sheets. The structure of AgNPs/rGO was determined by X-ray diffraction, Raman spectroscopy and X-ray photoelectron spectroscopy. Electrical conductive adhesives (ECAs) were prepared by mixing the micro silver flakes, AgNPs/rGO nanocomposites and epoxy together. To achieve the best electrical conductance, the optimal average size of the silver nanoparticles (AgNPs) in AgNPs/rGO composites is found to be about 20.7 nm. The results show that the resistivity of ECAs consisting of the AgNPs/rGO nanocomposites (0.2 wt% AgNPs/rGO and 69.8 wt% silver flake) was decreased compared with control sample (ECAs filled with 70 wt% silver flake). In particular, the resistivity of ECA filled with glucose-AgNPs/rGO (A-AgNPs/rGO) is 8.76 × 10 −5 Ω cm. In summary, A-AgNPs/rGO was determined to be a promising candidate filler for conductivity improvement of ECAs.
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CHINESE JOURNAL OF POLYMER SCIENCE
·
2015
·Vol. 34
·期 2
·229-241
·
IF 1.835
Zhang Hui,Zhang Ge,Xu Jing-kun,Wen Yang-ping,Ding Wan-chuan,Zhang Jie,Ming Shou-li,Zhen Shi-jie
An amino acid side chain functionalized polyfluorene derivative poly[ N -(9-fluorenylmethoxycarbonyl)-glycine] (P9FG) was facilely electrosynthesized and characterized, and the structure, properties and optical sensing application of the obtained polymer were described and discussed. The electropolymerization occurred at C 2 and C 7 positions of fluorene units, and amino acid side chain groups were not cleaved from polyfluorene backbone in mixed electrolytes of boron trifluoride diethyl etherate and dichloromethane. Thermal analysis demonstrated good thermal stability of P9FG. Fluorescent spectra indicated that P9FG was a good blue light emitting material that could be employed as optical sensors. The soluble P9FG as a turn-off fluorescent sensor could realize the detection of Fe 3+ , Cu 2+ and Cr 2 O 7
2- , respectively. In addition, P9FG as a turn-off ultraviolet sensor could realize the detection of Cu 2+ while as turn-on ultraviolet sensors could also realize the determination of Fe 3+ and Cr 2 O 7
2- , respectively. All results indicate that P9FG is a promising candidate for optical sensing.
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CHINESE JOURNAL OF OCEANOLOGY AND LIMNOLOGY
·
2015
·Vol. 34
·期 4
·789-794
·
IF 0.657
Chang Zhiqiang,Liu Fei,Lian Chun’ang,Zhai Qianqian,Li Jian
The pharmacokinetic profiles and sulfamethoxazole (SMX) acetylation process in turbot reared at 18°C were investigated. Either SMX (parent drug) or its acetylized metabolite, N 4 -acetylsulfamethoxazole (AcSMX), was administered intravascularly to turbot at a dosage of 50 mg/kg BW. Serum concentrations of the parent drug and its metabolite were both measured by HPLC, and the changes in concentration over time were analyzed in two- and non-compartment models because SMX treatment produced multiple peaks. The results demonstrated that the elimination half-life of the parent drugs, SMX and AcSMX, were 159.2 and 5.9 h, respectively. The apparent volume of distribution was 0.2 and 0.8 L/kg, and the clearance was 0.038 and 0.222 L/(h·kg), for SMX and AcSMX, respectively. SMX acetylation in turbot was 2.8%, and the deacetylation of AcSMX was 0.2%. These findings may be useful in optimizing SMX dosage regimens in turbot aquaculture.
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ECOTOXICOLOGY
·
2014
·Vol. 24
·期 2
·468-477
·
IF 2.5
Ran Xiaofei,Liu Rui,Xu Sha,Bai Fang,Xu Jinzhu,Yang Yanjun,Shi Junqiong,Wu Zhongxing
In this study, the effects of cadmium on the cyanobacterium Aphanizomenon flos - aquae , the green alga Pediastrum simplex and the diatom Synedra acus was evaluated on the basis of growth rate, chlorophyll a fluorescence, lipid peroxidation and antioxidant enzyme activity. The EC 50 values (effective concentration inducing 50 % of growth inhibition) of cadmium in A. flos - aquae , P. simplex and S. acus were 1.18 ± 0.044, 4.32 ± 0.068 and 3.7 ± 0.055 mg/L, respectively. The results suggested that cadmium stress decreases growth rate and chlorophyll a concentration. The normalized chlorophyll a fluorescence transients significantly increased at cadmium concentrations of 5.0, 10.0 and 20.0 mg/L, but slightly decreased at concentrations of 0.2, 0.5 and 1.0 mg/L. The chlorophyll fluorescence parameters showed considerable variation among the three species, while lipid peroxidation and antioxidant enzyme activities showed a significant increase. Our results demonstrated that blockage of electron transport on the acceptor side of photosystem II is the mechanism responsible for cadmium toxicity in freshwater microalgae, and that the tolerance of the three species to cadmium was in the order green alga P. simplex > diatom S. acus > cyanobacterium A. flos - aquae .
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高影响因子
Scientific Reports
·
2017
·Vol. 7
·期 1
·1-10
·
IF 4.259
Huang Renkun,Liang Ruowen,Fan Haimei,Ying Shaoming,Wu Ling,Wang Xuxu,Yan Guiyang
With increasingly stringent environmental regulations, the removal of nitrogen-containing compounds (NCCs) from gasoline fuel has become a more and more important research subject. In this work, we have successfully synthesized TiO 2 /α-Fe 2 O 3 heterogeneous photocatalysts with different mass ratios of TiO 2
vs . α-Fe 2 O 3 . Taking photocatalytic denitrification of typical alkali NCCs, pyridine, in gasoline fuel under visible light irradiation (λ ≥ 420 nm) as the model reaction, the TiO 2 /α-Fe 2 O 3 hybrids have exhibited enhanced photocatalytic activity compared with pure TiO 2 and α-Fe 2 O 3 , giving a pyridine removal ratio of ∼ 100% after irradiation for 240 min. The improved photocatalytic performance can be attributed to the integrative effect of the enhanced light absorption intensity and more efficient separation of photogenerated electron-hole pairs. Importantly, this type of heterogeneous photocatalysts can be easily separate in the reaction medium by an external magnetic field that is very important for industrial purpose. In addition, major reaction intermediates have been identified by the liquid chromatograph-mass spectrometer (HPLC-MS) and a tentative photocatalytic denitrification mechanism has been proposed.
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Journal of Food Measurement and Characterization
·
2017
·Vol. 11
·期 4
·1947-1958
·
IF 0.536
Zhao Zhenyu,Liu Pinghuai,Wang Shenglin,Ma Shasha
Ultrasonic-assisted extraction (UAE) and microwave-assisted extraction (MAE) were developed to extract flavonoids antioxidants from the root of Millettia speciosa ( Millettia speciosa Champ.). The optimal experimental parameters for antioxidant extraction from M. speciosa Champ. were measured using single-factor experimentation combined with response surface methodology (RSM). Final extraction rate (FER) of flavonoids assay was used to quantify antioxidant compounds. Then, 2,2ˊ-diphenyl-1-picryhydrazyl (DPPH) scavenging capacity, 2,2ˊ-azino-bis(3-ethylbenzothiazoline-6-sulphonicacid) (ABTS) scavenging capacity and ferric reducing antioxidant power (FRAP) were used to determine the antioxidant capacities of extract. Besides, UAE and MAE were compared with conventional Soxhlet extraction (CSE) and M. speciosa Champ. powders were observed by scanning electronic microscopy to analyze the damage of cell structure caused by different extraction methods. The results showed that UAE was the optimal extraction method to extract flavonoids compounds from M. speciosa Champ. and the optimized UAE conditions of flavonoids was as follows: ethanol, 80%, temperature, 40 °C and ultrasonic power, 500 W. This paper provided useful information to utilize the resource of Chinese herbal medicine and manifest the great antioxidant activities of M. speciosa Champ., and the optimized UAE conditions of flavonoids from M. speciosa Champ. could be used in industrial production.
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BMC Complementary and Alternative Medicine
·
2017
·Vol. 17
·期 1
·1-11
·
IF 2.288
Jiang Qian,Li Xican,Tian Yage,Lin Qiaoqi,Xie Hong,Lu Wenbiao,Chi Yuguang,Chen Dongfeng
Background
Mori Fructus and Mori Ramulus are two traditional Chinese herbal medicines from mulberries. The present work explores their beneficial effects on •OH–treated mesenchymal stem cells (MSCs) and discusses possible mechanisms.Methods Lyophilized aqueous extracts of Mori Fructus (LAMF) and Mori Ramulus (LAMR) were prepared and analyzed using HPLC. LAMF and LAMR (along with morin) were further investigated for their effects on •OH-treated MSCs using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl (MTT) assay. The direct antioxidation mechanisms were studied using 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (PTIO•)-scavenging, 2,2′-azino-bis (3-ethylbenzo-thiazoline-6-sulfonic acid (ABTS+•)-scavenging and 1,1-diphenyl-2-picryl-hydrazl (DPPH•)-scavenging, as well as Cu2+-reducing and Fe3+-reducing antioxidant power. Finally, the indirect antioxidant mechanism was investigated based on the UV-vis spectra of Fe2+-chelation.Results In each LAMF and LAMR, seven phytophenols were successfully measured by HPLC, including five flavonoids (morin, rutin, astragalin, isoquercitrin and luteolin) and two non-flavonoids (chlorogenic acid and maclurin). MTT assays revealed that LAMF, LAMR and morin could effectively increase the survival of •OH-treated MSCs at 10–100 μg/mL, and could effectively scavenge PTIO• (IC 50 6609.7 ± 756.6, 4286.9 ± 84.9 and 103.4 ± 0.9 μg/mL, respectively), DPPH• (IC 50 208.7 ± 3.0, 97.3 ± 3.1 and 8.2 ± 0.7 μg/mL, respectively) and ABTS+• (IC 50 73.5 ± 5.8, 34.4 ± 0.1 and 4.2 ± 0.2 μg/mL, respectively), and reduce Cu2+ (IC 50 212.5 ± 7.0, 123.2 ± 0.9 and 14.1 ± 0.04 μg/mL, respectively) & Fe3+ (IC 50 277.0 ± 3.1, 191.9 ± 5.2 and 5.0 ± 0.2 μg/mL, respectively). In the Fe2+-chelating assay, the five flavonoids produced much stronger shoulder-peaks than the two non-flavonoids within 420–850 nm.Conclusion
Mori Fructus and Mori Ramulus, can protect MSCs from •OH-induced damage. Such beneficial effects can mainly be attributed to the antioxidant action of phytophenols, which occurs via direct (ROS-scavenging) and indirect mechanism (Fe2+-chelating). The ROS-scavenging mechanism, however, include at least a H+-transfer and an electron-transfer (ET), and possibly includes a hydrogen-atom-transfer (HAT). In the Fe2+-chelating, flavonoids are more effective than non-flavonoids. This can be attributed to several adjacent planar chelating-sites between the 3-OH and 4-C = O, between the 4-C = O and 5-OH, or between the 3′-OH and 4′-OH in flavonoids. Such multiple-Fe2+-chelating reactions cause overlap in the UV-vis absorptions to deepen the complex color, enhance the peak strength, and form shoulder-peaks. By comparison, two non-flavonoids with catechol moiety produce only a weak single peak.
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Journal of Inorganic and Organometallic Polymers and Materials
·
2017
·Vol. 27
·期 5
·1162-1176
·
IF 1.577
Zeng Han,Yang Yang,Zhao Shu Xian,Zhang Yu He
Abstract Dependences of structural parameters and operational conditions on enzymatic catalysis of substrates (glucose and oxygen) for basal electrodes over-coated by composite consisting of nano-gold particle and polymer, were investigated systematically by the means of electrochemistry and spectrometry. Rate constants of steps involved in the whole catalytic cycle were estimated under the same dimension and were compared to confirm the limiting factor in the whole catalytic cycle. Results from experiments indicated that nano-gold particle surface anchored with aromatic ring as conductive support played the important role in achieving direct electron transfer between cofactors in redox protein molecules and electrical wired matrix. Complexations between components of nano-composite and redox sites within incorporated enzyme molecules acted as the paradoxical role in promoting the catalytic efficiency in the long term. Electrochemical conversion of substrates into product was identified to be the rate limiting step in the whole catalytic cycle for both enzyme based electrodes. Other parameters such as enzyme loading amounts in matrix, size of nano-particle and proportion of component in nano-composite only posed impact on magnitude of catalytic effect rather than the mechanism of catalysis. Graphical Abstract Transformation of substrate into product was ascribed to the limiting step in the whole catalysis for enzyme-based electrodes which resulted from great impact of interactions between enzyme carrier and redox protein on configuration of cofactors in enzyme molecules and binding ability to substrate for proteins.
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MICROCHIMICA ACTA
·
2017
·Vol. 184
·期 8
·2749-2757
·
IF 4.58
Mayang Yanchao,He Xiwen,Chen Langxing,Zhang Yukui
A surface plasmon resonance sensor whose surface has been modified with boronic acid groups was developed in order to bind and detect transferrin. 4-Mercaptophenylboronic acid (4-MPBA) was utilized to form a self-assembled monolayer on the gold surface of the sensor chip. The surface topography of the modified gold chip was characterized by atomic force microscopy. In solutions of pH 9, the glycosyl groups of transferrin (Trf) quickly and reversibly combine with 4-MPBA on the sensor chip to result in changes of the refractive index. Thus, Trf can be sensed online by monitoring the SPR signal. Under optimized conditions, the sensor has a linear response in the 10 nM to 1.3 μM Trf concentration range, and the limit of detection is 4.4 nM (equivalent to 0.34 μg·mL −1 ). The results suggest that this 4-MPBA-functionalized sensor is a viable candidate for clinical testing of Trf which is a potential marker for severe diseases such as hypertension, primary renal disease, and diabetes.
Schematic of a novel SPR sensor modified with boronic acid for the determination of transferrin in human urine with high sensitivity.
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