COLLOID AND POLYMER SCIENCE
·
2013
·Vol. 292
·期 4
·895-903
·
IF 2.161
Kang Wanli,Ji Yanfeng,Xu Bin,Hu Leilei,Meng Lingwei,Fan Haiming,Bai Baojun
The host cyclodextrin polymer-P(AM/A-β-CD/NaA) is prepared by redox free-radical copolymerization. Additionally, the multi-sticker amphiphilic polymer-P(AM/BHAM/NaA) as a guest polymer is synthesized using micellar polymerization. The copolymer structures are characterized by 1 H NMR. Subsequently, all the polymers and inclusion complexes are evaluated in terms of apparent viscosity, optical absorption spectra and rheological property. The results indicate that the inclusion association between the cyclodextrin group (CD) and multi-sticker hydrophobic monomer (BHAM) is in accordance with ternary interaction (CD/BHAM = 2:1). Because of the inclusion association between the host and guest polymers, the solution of inclusion complex has much higher viscoelasticity even under the low amphiphilic polymer concentration. When the molar ratio of CD to BHAM is 1:1, the critical aggregation concentration (CAC) of the inclusion complex solution still remains. Furthermore, above the CAC, two types of associations, inclusion association and inter-molecular hydrophobic association, can occur in the complex solution and these interactions were also verified by fluorescence spectroscopy and atomic force microscopy (AFM). In this paper, the inclusion rule of cyclodextrin polymer with the multi-sticker amphiphilic polymer is discussed, and the rule of the enhanced solution viscosity is further explored.
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Science China-Chemistry
·
2013
·Vol. 57
·期 3
·379-388
·
IF 1.327
Ma SongQi,Liu XiaoQing,Jiang YanHua,Fan LiBo,Feng JianXiang,Zhu Jin
A phosphorus-containing bio-based epoxy resin (EADI) was synthesized from itaconic acid (IA) and 9,10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide (DOPO). As a matrix, its cured epoxy network with methyl hexahydrophthalic anhydride (MHHPA) as the curing agent showed comparable glass-transition temperature and mechanical properties to diglycidyl ether in a bisphenol A (DGEBA) system as well as good flame retardancy with UL94 V-0 grade during a vertical burning test. As a reactive flame retardant, its flame-resistant effect on DGEBA/MHHPA system as well as its influence on the curing behavior and the thermal and mechanical properties of the modified epoxy resin were investigated. Results showed that after the introduction of EADI, not only were the flame retardancy determined by vertical burning test, LOI measurement, and thermogravimetric analysis significantly improved, but also the curing reactivity, glass transition temperature ( T
g ), initial degradation temperature for 5% weight loss ( T
d(5%) ), and flexural modulus of the cured system improved as well. EADI has great potential to be used as a green flame retardant in epoxy resin systems.
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WORLD JOURNAL OF MICROBIOLOGY & BIOTECHNOLOGY
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2013
·Vol. 30
·期 4
·1251-1260
·
IF 1.262
Zhou Gang,Shi Qing-shan,Ouyang You-sheng,Chen Yi-ben
Isothiazolones are used as preservatives in various modern industrial products. Although microorganisms that exhibit resistance towards these biocides have been identified, the underlying resistance mechanisms are still unclear. Therefore, we investigated the resistance properties of the following Burkholderia cepacia strains to Kathon (a representative of isothiazolones): a wild-type (WT) strain; a laboratory resistance strain (BC-IR) induced from WT; and an isolated strain (BC-327) screened from industrial contamination samples. The bacterial cell structure was disrupted by 50 μg ml −1 Kathon treatment. BC-IR and BC-327 did not display resistance in the presence of 1 ml L −1 Tween 80, 1 ml L −1 Triton X-100, 0.1 % sodium dodecyl sulfate or 1 mmol L −1 EDTA-2Na. Additionally, BC-IR and BC-327 exhibited lower relative conductivity from 10 to 180 min. The types as well as the levels of outer-membrane proteins (OMPs) were altered among WT, BC-IR and BC-327. Finally, the two Kathon-resistance strains BC-IR and BC-327 presented higher resistance capacity to H 2 O 2 . We measured the levels of peroxide-sensor genes and observed that the transcriptional activator oxyR , superoxide dismutase sod1 , sod2 , catalase cat1 and cat3 were all up-regulated under oxidative conditions for all strains. Taken together, OMPs and peroxide-sensor genes in B. cepacia contributed to isothiazolone resistance; However, the laboratory strain BC-IR exhibited a different resistance mechanism and properties compared to the isolated strain BC-327.
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PubMed
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JOURNAL OF NANOPARTICLE RESEARCH
·
2014
·Vol. 16
·期 5
·1-12
·
IF 2.278
Lv Shaonan,Zhao Meiqin,Cheng Changjing,Zhao Zhigang
β-Cyclodextrin (β-CD) polymer
brushes decorated magnetic Fe 3 O 4 colloidal nanocrystal clusters (Fe 3 O 4 @PG-CD) were fabricated by a combination of surface-initiated atom transfer radical polymerization on the surface of Br-anchored Fe 3 O 4 colloidal nanocrystal clusters (Fe 3 O 4 –Br) and ring-opening reaction of epoxy groups. The resulted Fe 3 O 4 @PG-CD hybrid nanoparticles were characterized by several methods including Fourier transform infrared, transmission electron microscope, dynamic light scattering instrument, X-ray diffraction, thermogravimetric analysis, and vibrating sample magnetometer. Moreover, the potential of as-synthesized Fe 3 O 4 @PG-CD as a carrier of hydrophobic anticancer drug 5-fluorouracil (5-FU) was also investigated. The results showed that the prepared Fe 3 O 4 @PG-CD have core/shell structure and high saturated magnetism. 5-FU could be loaded into the Fe 3 O 4 @PG-CD via the formation of β-CD/5-FU inclusion complex. Furthermore, the Fe 3 O 4 @PG-CD displayed a high loading capacity and pH-dependent release behavior for 5-FU. The release behavior demonstrated a simple Fickian diffusion in the acidic environment (pH 2.0 and 4.0) but neither non-Fickian nor anomalous when neutral. The results reveal that this nanosystem seems to be a very promising vehicle for the hydrophobic drugs for pH-dependent controlled release.
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JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY
·
2014
·Vol. 301
·期 1
·257-262
·
IF 1.415
Zha Zhongyong,Wang Dingna,Hong Wei,Liu Li,Zhou Sai,Feng Xiaojie,Qin Bing,Wang Jianmei,Yang Yi,Du Liang,Zhang Dong,Fang Zhendong,Xia Chuanqin
This study aimed at influence of europium speciation on its accumulation in Brassica napus (CK) and over-expressing BnTR1 lines (OE), and the kinetics of Eu uptake were investigated. These results indicated that the uptake in the roots of OE was higher than that of CK at high concentrations of europium and even the enrichment in the roots of OE was as high as 20,000 mg/kg at 328.9 μΜ Eu, this suggested that OE might have better resistance to uranium than CK. The time kinetics in plants showed that there had the similar trend between CK and OE. The formation of Eu 3+ at pH 5 in deionized water was beneficial to plants enrichment Eu and carbonate could reduce the adsorption of Eu in two group and phosphate almost completely impress the adsorption of Eu in two group, but citric acid could enhance europium root-to-shoot translocation in two group. These results would help understanding the mechanism of Eu uptake in Brassica napus (CK) and over-expressing BnTR1 lines (OE), therefore properly developing efficient europium/americium phytoremediation.
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JOURNAL OF MATERIALS SCIENCE
·
2014
·Vol. 49
·期 14
·5141-5150
·
IF 2.305
Zhuo Longhai,Kou Kaichang,Wang Yiqun,Yao Pan,Wu Guanglei
We report the design and synthesis of a novel pyridine-containing triamine monomer, 2,6-bis(4-aminophenyl)-4-(4-aminophenoxy)pyridine (BAAP), through combining the nucleophilic aromatic substitution with modified Chichibabin reaction and hydrazine hydrate reduction. Based on it, a novel three-step route was applied in order to obtain a series of new polyimides, containing phthalimide as pendent group and pyridine moieties in main chains. The three-step route consisted of terminating the triamine by incorporating phthalic amic acid as pendant, ring-opening polymerization to form poly(amic acid)s and further chemical imidization to acquire polyimides. Nuclear Magnetic Resonance Spectroscopy ( 1 H-NMR) was used for chemical structural characterization, and the results indicated the various forms of BAAP and branched structure units in the obtained polyimides. The morphology structures of the polyimides were evaluated by X-ray diffraction patterns, and the d -spacing values were found in the range of 4.14–4.65 Ǻ. Most of the resulting polyimides were soluble in polar aprotic solvents, such as NMP, DMF, DMAc, DMSO, and so on. Meanwhile, the polyimides exhibited excellent thermal stability, with the decomposition temperature at 5 and 10 % weight loss temperatures in the ranges of 399.1–461.1 °C and 481.1–566.9 °C, respectively. The polyimides, based on 6FDA, possessed the best comprehensive thermally stable and soluble performance.
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JOURNAL OF APPLIED PHYCOLOGY
·
2013
·Vol. 26
·期 1
·675-686
·
IF 2.326
Cao Yan,Duan Jinao,Guo Jianming,Guo Sheng,Zhao Jinlong
In this study the contents of nucleosides, nucleobases and free amino acids (FAAs) in common brown seaweeds Saccharina japonica , Sargassum pallidum , S. fusiforme , S. thunbergii and S. muticum from major production areas in China were determined by ultra-performance liquid chromatography coupled with triple quadrupole mass spectrometry (UPLC-TQ-MS). The total contents of nucleosides and nucleobases varied from 48.46 to 4,105.00 μg g −1 . Among the five seaweeds, levels of nucleosides and nucleobases in S. japonica were higher than the other species. The contents of ribonucleosides in these brown seaweeds were higher than those of deoxynucleosides. Uridine was the predominant constituent in all samples while 2′-deoxycytidine was the least in most samples. FAAs contents ranged from 0.14 to 22.76 mg g −1 . Among the five seaweeds, levels of FAAs in S. muticum were higher than the other species. Essential amino acids accounted for 3.26–51.49 % of total FAAs contents in different species. Glutamic acid was the major constituent in most samples. Four non-protein amino acids, γ-aminobutyric acid, taurine, hydroxyproline and citrulline, were found in the seaweed samples. Furthermore, principal component analysis (PCA) showed that chemical profiles of nucleosides, nucleobases and FAAs in S. pallidum and S. fusiforme were different from S. muticum , S. thunbergii and S. japonica . Common brown seaweeds could be promising natural sources for future industrial research into nucleosides, nucleobases and FAAs with potential benefits for human health.
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JOURNAL OF MATERIALS SCIENCE-MATERIALS IN MEDICINE
·
2013
·Vol. 24
·期 9
·2093-2100
·
IF 2.141
Guo Rui,Chen Lili,Cai Shushan,Liu Zonghua,Zhu Yi,Xue Wei,Zhang Yuanming
Polysaccharides based polyelectrolyte complex nanoparticles (PCNs) intended for use in the delivery of macromolecules were prepared by the self-assembly of deoxycholic acid hydrophobically modified chitosan (CS-DCA) core and then coated with sodium alginate (ALG) shell. The CS-DCA capable of forming nano-sized self-aggregates in medium was prepared by the grafting of DCA to CS. In order to increase the stability of nanoparticles and prevent burst release of drug in bloodstream, polyanionic ALG was coated on the surface of positively charged CS-DCA nanoparticles to form PCNs. Dynamic light scattering results revealed that the mean diameter of the PCNs was about 330 nm, larger than that of uncoated nanoparticles (~150 nm). The zeta potential was big enough to keep the stability of PCNs (−28 mV); no size change was found even upon 1 month storage. Bovine serum albumin could be easily incorporated into the PCNs with encapsulation efficiency (>44 %) and keep a sustained manner without burst release when exposed to PBS (pH 7.4) at 37 °C. These results suggested that PCNs may be a promising drug carrier for a prolonged and sustained delivery in the bloodstream.
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JOURNAL OF WUHAN UNIVERSITY OF TECHNOLOGY-MATERIALS SCIENCE EDITION
·
2013
·Vol. 28
·期 3
·617-621
·
IF 0.484
Zeng Rong,Wang Zehu,Wang Hongran,Chen Liqiang,Qiao Renzhong,Hu Liming,Li Zelin
Chitosan-stavudine (d4T) conjugate with a succinic spacer was synthesized via carbodiimide coupling reaction and structurally characterized. In order to nanosize it for improving its therapeutic properties, the chitosan-5′- O -succinyl-d4T conjugate was crosslinked with sodium tripolyphosphate (TPP) to obtain the chitosan-d4T conjugate nano-prodrug. The morphologies of chitosan-d4T conjugate nanoparticles were observed by transmission electron microscopy (TEM), and their zeta potential, particle size, and polydispersity (size distribution) were measured by the dynamic light scattering (DLS) techniques. In vitro drug release studies at pH 1.1 and pH 7.4 indicate that the crosslinked chitosan-d4T conjugate nano-prodrug can prevent the coupled d4T from leaking out before entering the target viral reservoirs and provide a mild sustained release without the burst release. The results reveal that constructing conjugated chitosan nano-prodrugs may be a promising approach for improving the therapy efficacy of drugs in antiviral treatment.
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MICROCHIMICA ACTA
·
2014
·Vol. 182
·期 1
·193-200
·
IF 3.719
Ren Xiaohui,Liu Haochi,Chen Ligang
We show that Mn(II)-doped ZnS quantum dots coated with an acrylamide-based molecularly imprinted polymer (MIP-coated QDs) can act as a fluorescent probe for the selective and sensitive detection of the insecticide chlorpyrifos (CPF). The fluorescence of the coated QDs is quenched on loading the MIP with CPF, and the effect is much stronger for the MIP than for the non-imprinted polymer. The MIP-coated QDs were characterized by fluorescence spectrophotometry, X-ray powder diffraction, and scanning electron microscopy. Under optimal conditions, the relative fluorescence intensity of the MIP-coated QDs decreases linearly with the increasing concentration of CPF in the 0.3–60 μmol L −1 concentration range, and the detection limit is 17 nmol L −1 . The method has been used for the determination of CPF in spiked water samples and gave recoveries in the range from 87.1 to 94.5 % with relative standard deviations in the 2.9 to 6.5 % range. The method is simple, safe and inexpensive.
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Reaction Kinetics Mechanisms and Catalysis
·
2014
·Vol. 113
·期 1
·281-292
·
IF 0.983
Huang Ji-guo,Zheng Meng-yang,Pang Shuo,Liu Li-guo,Zhao Xiao-guang,Dong Li-li,Liu Xing-juan
N–Si co-doped TiO 2 nanoparticles for the photodegradation of phenol were prepared by SiCl 4 and TiCl 4 co-hydrolysis and the effect of H 2 O 2 modification was studied. The characterization results revealed that the Si doped into the TiO 2 lattice was limited and the redundant silicon existed in segregated amorphous silica. The average crystallite size of the photocatalysts reduced from 14.8 to 5.5 with increasing Si doping ratio. The absorption edges of the as-prepared samples got an obvious red shift in which the best one reached 526 nm. N and Si co-doped into the photocatalysts replaced Ti and formed the Ti–O–Si and O–Ti–N link-ages. The photocatalysts modified by H 2 O 2 were well dispersed and changed the molecular structure. The degradation effect of the used Si doped photocatalysts was better than for undoped photocatalysts, and the H 2 O 2 modification could not further enhance the photocatalytic activity for N–Si doped TiO 2 . For the photodegradation of phenol, the optimal molar ratio of Si/Ti and the calcination temperature was 1:4 and 650 °C, respectively. For the optimal photocatalyst, the molar ratios of O/Ti, N/Ti, and Si/Ti were 0.54, 0.19, 0.29, and the phenol removed 94.4 % in 6 h under solar light. The reusability of N–Si co-doped TiO 2 was relatively good.
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BIOLOGICAL TRACE ELEMENT RESEARCH
·
2014
·Vol. 159
·期 1
·393-398
·
IF 1.608
Jin Chan,Wang Fude,Tang Ying,Zhang Xiangzhi,Wang Jianqiang,Yang Yongji
Graphene and its derivatives are increasingly applied in nanoelectronics, biosensing, drug delivery, and biomedical applications. However, the information about its cytotoxicity remains limited. Herein, the distribution and cytotoxicity of graphene oxide (GO) and TiO 2 -graphene oxide composite (TiO 2 -GO composite) were evaluated in A549 cells. Cell viability and cell ultrastructure were measured. Our results indicated that GO could enter A549 cells and located in the cytoplasm and nucleus without causing any cell damage. TiO 2 nanoparticles and GO would be separated after TiO 2 -GO composite entered A549 cells. TiO 2 -GO composite could induce cytotoxicity similar to TiO 2 nanoparticles, which was probably attributed to oxidative stress. These results should be considered in the development of biological applications of GO and TiO 2 -GO composite.
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