APPLIED SURFACE SCIENCE
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2012
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IF 2.103
Baolin Zhang,Zhijiang Tu,Fangyuan Zhao,Jun Wang
Superparamagnetic iron oxide nanoparticles were synthesized by thermal decomposition of iron (III) acetylacetonate (Fe(acac) 3 ) in PEG containing poly(vinyl pyrrolidone) (PVP) or poly(ethylene imine) (PEI). The morphologies and phase compositions of the nanoparticles were determined by transmission electron microscopy and X-ray diffraction, respectively. The surface coating of the nanoparticles was recognized using Fourier transform infrared spectroscopy and the presence of the surface coating was confirmed by Thermogravimetric analyses. Magnetic properties were measured using superconducting quantum interference device. The zeta potentials and hydrodynamic sizes of the nanoparticles were determined using nano-particle and zeta potential analyzer. The superparamagnetic iron oxide nanoparticles with sizes from 4.1 nm to 14.9 nm were prepared in the present work, which could be tuned by varying factors such as the reaction temperature, the reaction time, and the PVP or PEI contents. The superparamagnetic nanoparticles were jointly coated with PEG/PVP or PEG/PEI. With hydrodynamic sizes smaller than 40 nm and neutral or positive zeta potentials these superparamagnetic iron oxide nanoparticles exhibited higher dispersion stability in deionized water and in phosphate buffered saline as compared with the superparamagnetic iron oxide nanoparticles coated with PEG alone. This work demonstrates that superparamagnetic iron oxide nanoparticles with modulated properties can be prepared simply by using the improved polyol method.
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Analytical Methods
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2014
·Vol. 6
·期 6
·1753-1758
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IF 1.938
Yue Zhao,Yongling Du,Daban Lu,Letao Wang,Deyuan Ma,Tianzhen Ju,Menglong Wu
An arginine (Arg) functionalized graphene (Arg-G) nanocomposite was produced successfully and the procedure was environment-friendly. An electrochemical sensor based on the Arg-G nanocomposite was developed for the determination of vanillin. The Arg-G modified glassy carbon electrode (GCE) showed excellent sensitivity properties by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Under the optimized conditions, the oxidation peak current was proportional to vanillin concentration in the range of 2.0 × 10−6 to 7.0 × 10−5 mol L−1 with the correlation coefficient of 0.9986 and the detection limit of 1.0 × 10−6 mol L−1 (S/N = 3). Moreover, the sensor could be used for the detection of vanillin in real food samples with satisfactory results.
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MICROPOROUS AND MESOPOROUS MATERIALS
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2014
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IF 3.209
Yuchao Wang,Liyan Zhang,Shengyang Tao,Yonglin An,Changgong Meng,Tao Hu
Composite phase change material (PCM) was prepared by loading pure PCM in the hierarchically porous silica (HPS) matrix. Via the modification by organic silanes, the surface property of the hybrid silica material was effectively controlled. The functional surface groups were not only helpful to reach high loading capacity for PCM (up to 3.5 times of HPS’s weight), but beneficial to enhance the energy storage capacity in confinement. An extra energy increase (about 10% of the total enthalpy value) could be revealed during the phase change process due to the strong van der Waals interaction between modified surface and PCM. The latent heat values of composite PCM (including HPS) could be 163.0 J g −1 . The PCM in modified HPS showed high thermal storage capability (about 99.34% to pure PCM). It was important to study the influence of modified surface on energy storage in confined space. The discussion would be useful to advance high-performance PCM composites.
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ACS Applied Materials & Interfaces
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2013
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IF 5.008
Yi Gong,Ai Mei Zhu,Qiu Gen Zhang,Mei Ling Ye,Hai Tao Wang,Qing Lin Liu
Cell encapsulation by locking the interfacial microgels in a water-in-oil Pickering emulsion has currently been attracting intensive attention because of the biofriendly reaction condition. Various kinds of functional microgels can only stabilize an oil-in-water Pickering emulsion, and it is thus difficult to encapsulate cells in the emulsion where the cells are usually dispersed in the continuous phase. Herein, we introduce a facile method for preparing cell-embedded colloidosomes in an oil-in-water emulsion via polyelectrolyte complexation. Escherichia coli (E. coli) was chosen as a model cell and embedded in the thin shell of chitosan/poly(N-isopropylacrylamide-co-acrylic acid) (P(NIPAM-co-AAc)) microcapsules. This is beneficial for expressing cell function because of the little resistance of mass exchange between the embedded cells and the external environment. Cells can be used in biocatalysis or biomedicine and our product will hold great promises to improve the performance in those fields. The synthesis route presents a platform to prepare cell-embedded microcapsules in an oil-in-water Pickering emulsion in a facile and biocompatible way. First, an emulsion stabilized by P(NIPAM-co-AAc) microgels was prepared. Then, the interfacial microgels in the emulsion were locked by chitosan to form colloidosomes. The mechanism of cell encapsulation in this system was studied via fluorescent labeling. The viability of E. coli after encapsulation is ca. 90%. Encapsulated E. coli is able to metabolize glucose from solution, and exhibits a slower rate than free E. coli. This demonstrates a diffusion constraint through the colloidosome shell.
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International Journal of Polymer Science
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2015
·
IF 1.195
Shi-Jia Dong,Bi-Xian Zhang,Yun-Fei Gao,Xiao-Mei Hu
Background and Aims. The complex structure of the lignocelluloses is the main obstacle in the conversion of lignocellulosic biomass into valuable products. Ionic liquids provide the opportunities for their efficient pretreatment for biomass. Therefore, in this work, pretreatment of corn stalk was carried out in ultrasonic-assisted ionic liquid including 1-butyl-3-methylimidazolium chloride [BMIM]Cl, 1-H-3-methylimidazolium chloride [HMIM]Cl, and 1-(1-propylsulfonic)-3-imidazolium chloride [HSO3-pMIM]Cl at 70°C for 2 h. We compared the pretreatments by ionic liquid with and without the addition of deionized water. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were employed to analyze the chemical characteristics of regenerated cellulose-rich materials. Results. [HMIM]Cl and [HSO3-pMIM]Cl were effective in lignin extraction to obtain cellulose-rich materials. FTIR analysis and SEM analysis indicated the effective lignin removal and the reduced crystallinity of cellulose-rich materials. Enzymatic hydrolysis of cellulose-rich materials was performed efficiently. High yields of reducing sugar and glucose were obtained when the corn stalk was pretreated by [HMIM]Cl and [HSO3-pMIM]Cl. Conclusions. Ionic liquids provided the ideal environment for lignin extraction and enzymatic hydrolysis of corn stalk and [HMIM]Cl and [HSO3-pMIM]Cl proved the most efficient ionic liquids. This simple and environmentally acceptable method has a great potential for the preparation of bioethanol for industrial production.
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RSC Advances
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2014
·Vol. 4
·期 64
·33866-33873
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IF 3.708
Zheng-Yong Chen,Hong-Wen Gao,Jia-Xiang Yang
The PEI@Mg2SiO4 hybrid composite is readily synthesized for adsorbing carbon dioxide (CO2) and nitrophenol compounds (NACs), in which more than 11% PEI is embedded. By the removal rate of 4-nitrophenol (10 mg L−1) and the capture capacity of CO2, the Mg2+ : PEI : SiO32− optimal mole ratio of the PEI@Mg2SiO4 is 1 : 0.6 : 1.5. The composite shows the highest adsorption amounts of 0.94 mmol g−1 CO2 at 50 °C. The heat treatment regeneration exhibits a good stability, e.g. the CO2 capture capacity decreases by only 20% after four cycles, and the desorption rate of CO2 remains more than 91%. It also exhibites a fast adsorption and high capacity for 4-nitrophenol (NP), 2,4-dinitrophenol (DNP) and 2,4,6-trinitrophenyl group (TNP). The adsorption capacity of NP, DNP and TNP is 2.40 mmol g−1, 2.66 mmol g−1 and 4.85 mmol g−1 respectively, which is more than that of the conventional sorbents. This work presents the higher capacity and eco–friendly sorbent for CO2 and nitrophenol compounds.
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ACS Nano
·
2017
·
IF 13.942
Fangfang Cao,Enguo Ju,Yan Zhang,Zhenzhen Wang,Chaoqun Liu,Wei Li,Yanyan Huang,Kai Dong,Jinsong Ren,Xiaogang Qu
Silver nanoparticles (AgNPs) have been used as a broad-spectrum antimicrobial agent, whose toxicity originates from the localized release of Ag+ ions. However, the residual AgNPs core could generate potential risk to humans and waste of noble metals. Herein, we infused the cysteine-modified molybdenum disulfide with minimum Ag+ ions and coated with a layer of cationic polyelectrolyte to construct an efficient and benign antimicrobial depot. The system exhibited much enhanced broad-spectrum antibacterial activity compared with an equivalent amount of silver nitrate, owing to its increasing accessibility of released Ag+ to the cell walls of microorganisms. More importantly, the antibacterial system could be successfully applied to treat wound infection, while retaining high antibacterial activities, exhibiting negligible biotoxicity and avoiding the waste of Ag.
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NANOTECHNOLOGY
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2016
·Vol. 27
·期 23
·23LT01
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IF 3.573
Libin Yang,Honglan Qi,Chengxiao Zhang,Xuping Sun
The development of highly efficient electrocatalysts for water splitting is critical for various renewable-energy technologies. In this letter, we demonstrate a cobalt phosphide nanowire array grown on a Ti mesh (CoP/TM) behaving as a bifunctional electrocatalyst for water splitting. The CoP/TM electrode delivers 10 mA cm−2 at an overpotential of 72 mV for the hydrogen evolution reaction (HER) and 310 mV for the oxygen evolution reaction (OER) in 1.0 M KOH. Furthermore, its corresponding two-electrode alkaline electrolyzer displays 10 mA cm−2 at 1.64 V.
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RSC Advances
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2016
·Vol. 6
·期 26
·21337-21344
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IF 3.289
Hong Jiang,Songlin Xue,Yefei Liu,Rizhi Chen,Weihong Xing
The Pd@ZIF-L catalysts with uniform crosshair-star shape and a size of about 20 μm were fabricated by an assembly method that enables the crystallization of ZIF-L in water with the presence of polyvinylpyrrolidone (PVP)-stabilized Pd nanoparticles (NPs). The physical and catalytic properties of the Pd@ZIF-L catalysts are greatly affected by the molar ratios of 2-methylimidazole (2-MeIM)/Zn2+ and PVP/Zn2+. Their catalytic activities were evaluated by the catalytic reduction of p-nitrophenol to p-aminophenol. The results indicate that a lower molar ratio of 2-MeIM/Zn2+ is beneficial for the increase of Pd loading and p-nitrophenol conversion, but a suitable molar ratio (≥20) of 2-MeIM/Zn2+ is helpful to the crystallization of ZIF-L and the encapsulation of the Pd NPs within the ZIF-L framework. The Pd@ZIF-L catalyst synthesized at a lower PVP/Zn2+ molar ratio has higher Pd loading and p-nitrophenol conversion due to the easy adsorption of PVP–Pd NPs onto the ZIF-L surfaces. This work would aid the development of high-performance Pd@ZIF-L catalysts.
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MATERIALS LETTERS
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2016
·
IF 2.437
Bo Chen,Yang Li,Xiquan Zhang,Fei Liu,Yanlong Liu,Min ji,Fei Xiong,Ning Gu
Ferumoxytol (Feraheme™), as one kind of magnetic nanoparticles (MNPs), was approved for clinical application in USA and widely used as magnetic resonance imaging (MRI) agent in tumor and inflammation for preclinical diagnosis research. In this study, we explored a novel synthesis of ferumoxytol induced by alternating-current magnetic field (ACMF). As-prepared ferumoxytol was characterized by transmission electron microscopy (TEM), particle size analyzer, fourier transform infrared spectrometer (FT-IR), X-ray diffraction (XRD), vibrating sample magnetometer (VSM) and heating measurement in ACMF. Relative characterizations proved that as-synthesized ferumoxytol demonstrated better quality than Feraheme™ that was prepared by ordinary chemical co-precipitation on particle size distribution , crystallinity and magnetism . Above all, this ACMF induced synthesis may offer a better strategy for ferumoxytol preparation.
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LANGMUIR
·
2016
·
IF 3.993
Yanhong Liu,Guozhu Li,Runze Qin,Danlei Chen
Mussel-inspired polydopamine (PDA) particles with the size of ∼270 nm are used as a support of palladium (Pd) nanoparticles (NPs) for catalyst preparation. The surface morphology of the PDA particle has been modified via corrosion of CF3COOH. Surface chemistry of the obtained PDA particle has been engineered by the formation of a carboxylic acid-terminated alkanethiol monolayer. The obtained self-assembled monolayer-modified PDA (SAM-PDA) particles are used to load Pd NPs by simply adding H2PdCl4 solution to a suspension of SAM-PDA particles at room temperature. Transmission electron microscopy, energy-dispersive X-ray mapping, dynamic light scattering, X-ray diffraction, X-ray photoelectron spectroscopy, UV–vis, and Fourier transform infrared are used to characterize the catalyst and to investigate the process. Uniform Pd NPs (2–3 nm) have been well-dispersed on the SAM-PDA particles via controllable surface engineering. Surface charges and interactions with a metal ion are regulated by the monolayer of carboxylic acids. The surface chemistry of PDA particles has been finely engineered for efficient loading of noble metal NPs. The obtained Pd/SAM-PDA catalyst has shown greatly increased activity and good reusability compared with Pd/PDA in the reduction of 4-nitrophenol (4-NP) by sodium borohydride or H2. The kinetic data of 4-NP hydrogenation catalyzed by Pd/SAM-PDA are fitted to a Langmuir–Hinshelwood (L–H) model, and the calculated apparent activation energy of this process is 40.77 kJ mol–1.
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JOURNAL OF PHARMACEUTICAL SCIENCES
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2016
·
IF 2.641
Sai-Fei He,Xian-Rui Zhang,Shuo Zhang,Su Guan,Jing Li,Shan Li,Lei Zhang
Three 1:1 salts containing vortioxetine (VOT), an orally antidepressant drug, and 3 aryl monoacids have been designed and successfully prepared by liquid-assisted grinding based on the ΔpK a rule. The C-O bond lengths (∼1.25 Å) in the COOH groups show that the proton transfer has occurred from aryl monoacid to piperazine N1 atom of vortioxetine in the crystal structures. Three salts feature cyclic [2 + 2] structural units through R 4 4 (12) N–H···O hydrogen bonding interactions which result in the remarkable thermal stabilities, and VOT– p -aminobenzoic acid shows 2-dimensional framework by linking cyclic [2 + 2] units through additional hydrogen bonding interactions. The equilibrium solubility of VOT in VOT– p -aminobenzoic acid salt can be largely improved up to 0.50 mg/mL (about 450% above the free base) at 25°C in water, which also accelerates the intrinsic dissolution rate.
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