JOURNAL OF MATERIALS SCIENCE
·
2013
·Vol. 48
·期 11
·3926-3935
·
IF 2.163
Ghosh Arun,Ma Lie,Gao Changyou
Chitosan-like bio-derived polymers possess a number of useful biological properties, but their mechanical and thermal durability needs to be improved to produce performance-driven materials. Inorganic particles are commonly used as fillers to provide reinforcement in polymer matrix. Zeolites are commercially important inorganic materials that are used extensively as adsorbents, ionic exchangers, and catalysts. One form of zeolite, known as molecular sieve 5A, is a Na + and Ca 2+ exchanged zeolite type A with a 1:1 Si:Al ratio. In this study, the role of zeolite as a reinforcing filler in a chitosan/malonic acid composite was investigated. The thermal stability, mechanical properties, and morphology of the chitosan matrix and chemical interactions within the composites were evaluated. It was observed that zeolite significantly improved the tensile strength, modulus, and thermal stability of chitosan and created a fibrous network-like morphology in the chitosan matrix. This study revealed that the inclusion of zeolite molecular sieve 5A improves the performance of chitosan-based biomaterials.
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EUROPEAN FOOD RESEARCH AND TECHNOLOGY
·
2014
·Vol. 240
·期 3
·627-634
·
IF 1.387
Ma Huihui,Zhang Niya,Sun Lvhui,Qi Desheng
Aflatoxin contamination levels vary from crop to crop, suggesting that it is of great significance to explore the effects of different substrates on aflatoxins production. In this study, the effects of corn, wheat, peanut, and soybean on aflatoxin B 1 (AFB 1 ) production by Aspergillus parasiticus were investigated, and the effects of corn germ, wheat germ, soybean, and peanut oils on the production of AFB 1 by A . parasiticus in the corresponding defatted substrates were evaluated at the rates of 2, 5, 10, and 15 g/100 g of substrate. The effects of the combinations of different oils with different defatted substrates on the accumulation of AFB 1 by A . parasiticus were also studied. AFB 1 concentration was determined by HPLC. The results indicated that high-lipid substrates of soybean and peanut had significantly higher AFB 1 production than low-fat substrates of wheat and corn throughout the entire incubation period (15 days) in both autoclaved and non-autoclaved grains. Corn germ, wheat germ, soybean, and peanut oils with different doses could effectively stimulate AFB 1 accumulation, and AFB 1 production was determined by the oil content of the substrates. Our results suggest that the oil content of substrates is one of the factors affecting AFB 1 production by A . parasiticus and that the composition and content of the substrates may also play a role.
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ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2014
·Vol. 22
·期 7
·5563-5571
·
IF 2.757
Li Yu-jiao,Hu Peng-jie,Zhao Jie,Dong Chang-xun
Composite washing of cadmium (Cd)- and lead (Pb)-contaminated agricultural soil from Hunan province in China using mixtures of chlorides (FeCl 3 , CaCl 2 ) and citric acid (CA) was investigated. The concentrations of composite washing agents for metal removal were optimized. Sequential extraction was conducted to study the changes in metal fractions after soil washing. The removal of two metals at optimum concentration was reached. Using FeCl 3 mixed with CA, 44 % of Cd and 23 % of Pb were removed, and 49 and 32 % by CaCl 2 mixed with CA, respectively. The mechanism of composite washing was postulated. A mixture of chlorides and CA enhanced metal extraction from soil through the formation of metal–chloride and metal–citrate complexes. CA in extract solutions promoted the formation of metal–chloride complexes and reduced the solution pH. Composite washing reduced Cd and Pb in Fe–Mn oxide forms significantly. Chlorides and CA exerted a synergistic effect on metal extraction during composite washing.
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JOURNAL OF MATERIALS SCIENCE
·
2014
·Vol. 49
·期 9
·3391-3399
·
IF 2.305
Jie Zhiqiang,Zhang Bing,Zhao Lianhong,Yan Xiufang,Liang Jie
A novel regenerable antimicrobial silica gel was prepared by a dehydration between silanols of silica gel and hydrolyzed 3-chloropropyltrimethoxysilane, a quaternization between grafted hydrolyzed 3-chloropropyltrimethoxysilane and (5,5-dimethylhydantoinyl-3-ylethyl)-dimethylamine (DHEDA), and a chlorination of amide groups of DHEDA. The as-prepared antimicrobial silica gel was characterized by FT-IR and X-ray photoelectron spectroscopy. Antimicrobial tests showed that the as-prepared antimicrobial silica gel was capable of about a 6-log inactivation of Staphylococcus aureus and Escherichia coli O157:H7 within 10 min of contact. Interestingly, more than 2 × 10 4 CFU/mL of Escherichia coli O157:H7 could be almost inactivated under flowing water condition. Furthermore, the as-prepared antimicrobial silica gel exhibits good regenerability and storage stability.
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MICROCHIMICA ACTA
·
2014
·Vol. 181
·期 5
·565-572
·
IF 3.719
Ma Ming,Tu Xiaojing,Zhan Guoqing,Li Chunya,Zhang Shenghui
The ionic liquid 1-butyl -3-[3-(N-pyrrole)-propyl]imidazolium tetrafluoroborate was employed to fabricate a glassy carbon electrode (GCE) modified with a porous film of a polymerized ionic liquid. The resulting film electrode was treated with sodium dodecyl sulfonate solution to exchange the terafluoroborate anions by dodecyl sulfonate groups. This was confirmed by X-ray photoelectron spectroscopy. The morphology of the modified GCE was characterized by scanning electron microscopy and revealed a nanoporous surface. The electrochemical properties of this film electrode were studied by electrochemical impedance spectroscopy using the hexacyanoferrate(II/III) system as an electroactive probe. The response to bisphenol A was investigated by voltammetry. Compared to the unmodified GCE, the oxidation potential is positively shifted, and the oxidation peak current is strongly increased. Experimental conditions were optimized and resulted in an oxidation peak current that is linearly related to concentration of bisphenol A in the 10 nM to ~ 10 μM range. The detection limit is 8.0 nM (at S / N = 3). The electrode was successfully applied to the determination of bisphenol A in leachates of plastic drinking bottles, and its accuracy was verified by independent assays via HPLC.
A poly{1 -butyl -3 -[3 -(N -pyrrole)propyl] imidazolium dodecyl sulfonate ionic liquid} nanoprous film electrode was fabricated with potential step technique and anionic exchange. The obtained polymerized ionic liquid film electrode was demonstrated possessing enhanced effects for bisphenol A determination.
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Journal of Inorganic and Organometallic Polymers and Materials
·
2013
·Vol. 24
·期 3
·582-590
·
IF 1.174
Li Xin,Bi Cai-Feng,Fan Yu-Hua,Zhang Xia,Zhang Nan,Yan Xing-Chen
A novel transition metal coordination polymer [Co 3 (C 14 H 8 NO 4 Cl) 4 (CH 3 OH) 4 ·4CH 3 OH] n with Schiff base (C 14 H 8 NO 4 Cl: 4-chloroanthranilic acid- 2,4-dihydroxybenzaldehyde) was synthesized using 4-chloroanthranilic acid, 2,4-dihydroxybenzaldehyde and cobalt(II) acetate as source, and its structure was characterized by IR spectroscopy, elemental analysis, 1 H NMR and single crystal X-ray diffraction. X-ray crystallography shows that every cobalt atom is six-coordinated. Two cobalt atoms on the two sides are respective coordinated with two nitrogen atoms from –C=N–, two carboxylic oxygen atoms and two hydroxyl oxygen atoms in different ligands, while the cobalt atom in the middle links two ligands on the side through two carboxylic oxygen atoms and coordinates with four oxygen atoms of methanol, forming a three-nuclear Co(II) complex. The complex forms a two-dimensional layer structure through O–H···O intermolecular hydrogen bonds. The interaction of the Co(II) complex with calf-thymus DNA (CT-DNA) was investigated by UV absorption spectroscopy, fluorescence emission spectroscopy, viscosity and cyclic voltammetry. All measurements revealed that the Co(II) complex binds to DNA via a intercalative mode.
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BIOMEDICAL MICRODEVICES
·
2013
·Vol. 16
·期 2
·237-243
·
IF 2.718
Lei Jian,Lei Chong,Wang Tao,Yang Zhen,Zhou Yong
An investigation of targeted biomolecules was accomplished by combining a micro-fluxgate-based bio-sensing system and Dynabeads. The fluxgate sensor for biomolecule detection was fabricated by Micro Electro-Mechanical system technology, including thick photoresist lithography, electroplating and chemical wet etching. The magnetic core of the sensor was made of Fe-based amorphous ribbon core and three dimension solenoid coils were used as magnetic sensitive elements. The micro-fluxgate-based bio-sensing system was characterized firstly in different concentrations of Dynabeads, and a concentration as low as 100 ng/ml was detected with an external dc magnetic field in the range of 525 μT to 875 μT. Sandwich assays are performed using antibody-antigen pair combination of biotin-streptavidin on a separated Au film substrate surface with a self-assembled layer. Detection of Alpha Fetoprotein antigens with different concentrations was performed and a minimum detectable concentration of 1 pg/ml was achieved by the bio-sensing system. It is of considerable interest due to its potential application in the biomedical field based on known specific binding of target and labels.
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Food Analytical Methods
·
2013
·Vol. 7
·期 7
·1381-1386
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IF 1.969
Ma Xiaoxing,Wang Juntao,Wu Qiuhua,Wang Chun,Wang Zhi
A new analytical method by graphene-reinforced hollow fiber liquid-phase microextraction combined with high-performance liquid chromatography fluorescence detection was developed for the determination of bisphenol A and 4- tert -butylphenol in bottled juices. Several important experimental parameters were studied to get optimal extraction conditions for the analytes. Under the optimized conditions, the method showed a good performance having a linear response in the range from 0.05 to 10.0 ng mL −1 with the correlation coefficients ( r ) of 0.9965–0.9994 and limits of detection of 0.01 ng mL −1 . The relative standard deviations were in the range from 6.4 to 7.2 % at the spiked concentration of 1.0 ng mL −1 . The method combines the high-adsorption capacity of graphene and the excellent clean-up performance of hollow fiber liquid-phase microextraction and has been successfully applied to the analysis of the analytes in bottled juice samples.
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APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
·
2014
·Vol. 118
·期 2
·621-628
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IF 1.694
Wang Han,Li Minhao,Huang Shenneng,Zheng Junwei,Chen Xin,Chen Xindu,Zhu Ziming
Interest in near-field electrospinning for high-precision positioning in additional material manufacturing has expanded in recent years. In order to increase the high-precision production rate, a methodology has been proposed to add the number of jets by using nozzle arrays in near-field electrospinning. To define the mutual influence of the jets, deposition characteristics of the double-nozzle near-field electrospinning have been observed. This paper described the work and results of the experimental investigation and the theoretical derivation. Experimentally, such effects are demonstrated through use of a 4 % polyethylene oxide solution. The deposition rule of double nozzle near-field electrospinning has been learned in accordance with Coulomb’s law. Experimental results showed that the mutual distance of the deposition becomes larger with increases in the voltage, needle spacing, and working distance. Theoretical derivation based on the net electric field environment has been studied to verify accuracy of the experimental conclusion.
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MONATSHEFTE FUR CHEMIE
·
2014
·Vol. 145
·期 12
·1925-1931
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IF 1.347
Tu Xingzhao,Zhou Lihong,Li Zhijie,Lei Ning,Zeng Qingle
Abstract The carbon-heteroatom bond formation is an important research field. Transition-metal-free synthesis of medicinally important heterocycles avoids products of transition metal contamination, and thus it is an environmentally friendly and cost-saving process. A transition-metal-free domino C-S/C-N formation for the synthesis of imidazobenzothiazines from 2-mercaptobenzimidazoles and 2-halobenzyl bromides is developed. The desired products were obtained in good to excellent yields. The mechanism of domino nucleophilic substitution (S N 2) and nucleophilic aromatic substitution (S N Ar) is proposed. Graphical abstract
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CHINESE JOURNAL OF POLYMER SCIENCE
·
2014
·Vol. 32
·期 3
·292-304
·
IF 1.42
Li Zhi-min,Zhang Gang,Li Dong-sheng,Yang Jie
Highly refractive and transparent polyamides containing thiadiazole units have been developed. These polymers were prepared by a polycondensation reaction of 4,4′-(1,3,4-thiadiazole-2,5-thio) bis(methylene) dibenzoyl chloride (TDTBM-DC) and diamine which contained thioether (-S-) and sulfone units. They showed good thermal stabilities such as a relatively high glass transition temperature of 206–233 °C and a 5% weight-loss temperature ( T
5% ) of 376–395 °C. The optical transmittance of the polymer at 450 nm is higher than 83%. The heterocycle units and plural -S- linkages provide the polymer with a high refractive index of 1.716–1.725 at 633 nm and a low birefringence of 0.003–0.004. Also they showed improved solubility in polar aprotic solvents and could form moderate strength films with tensile strength of 72.8–83.1 MPa and storage modulus of 1.0–1.8 GPa (at 200 °C).
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JOURNAL OF MATERIALS SCIENCE-MATERIALS IN MEDICINE
·
2015
·Vol. 26
·期 8
·1-13
·
IF 2.587
Ma Shengnan,Zhou Jie,Wali Aisha Roshan Mohamed,He Yiyan,Xu Xianghui,Tang James Zhenggui,Gu Zhongwei
Abstract
In this study, the amphiphilic fluorinated peptide dendrons functionalized dextran (FPD-HZN-Dex) via an acid-sensitive hydrazone linkage was successfully designed and prepared for the first time. We demonstrated a spontaneous self-assembly of amphiphilic FPD-HZN-Dex into the well-defined nanoparticles with the core-shell architecture in aqueous media, which is attributed to the efficient amphiphilic functionalization of dextran by the hydrophobic fluorinated peptide dendrons. The spherical morphology, uniform particle size and good storage stability of the prepared FPD-HZN-Dex nanoparticles were characterized by dynamic light scattering and transmission electron microscopy, respectively. In vitro drug release studies showed a controlled and pH dependent hydrophobic drug release profile. The cell viability assays show excellent biocompatibility of the FPD-HZN-Dex nanoparticles for both normal cells and tumor cells. Moreover, the FPD-HZN-Dex self-assembled systems based on pH-sensitive hydrazone linkage also can serve as stimulus bioresponsive carriers for on-demand intracellular drug delivery. These self-assembled nanoparticles exhibit a stimulus-induced response to endo/lysosome pH (pH 5.0) that causes their disassembly over time, enabling controlled release of encapsulated DOX. This work has unveiled a unique non-covalent interaction useful for engineering amphiphilic dendrons or dendrimers self-assembled systems. Graphical Abstract
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危险品化学品经营许可证（带存储）