JOURNAL OF MATERIALS SCIENCE
·
2014
·Vol. 50
·期 6
·2480-2490
·
IF 2.305
Wei T.,Ye L.,Zhao C. Z.,Wang W. B.,Ma Q. Z.,Lv Q.,Liu J. M.
Filled tetragonal tungsten bronze (FTTB) oxides represent a huge family of materials which exhibit rich electric and magnetic functionalities deserving for comprehensive investigations. Recently, some members of this family have established their significance in efficient upconversion (UC) luminescence upon proper rare-earth species doping, while the signal intensity is yet weak. In this work, the UC luminescence of Ba
p
Ln 6− p
Ti 8− p
Nb 2+ p
O 30 codoped by Ho and Yb (BLTN p :Ho–Yb) with different p are studied. The bright UC green emission, red emission, and near-infrared (NIR) emissions, originating from the two-photon energy-transfer process associated with the 5 S 2 → 5 I 8 , 5 F 5 → 5 I 8 , and 5 S 2 → 5 I 7 transitions of Ho 3+ ions, were observed. The luminescence intensity demonstrates remarkable dependence on the A- and B-sites occupation, and the UC green, red, and NIR luminescence can be enhanced for 10, 25, and 10 times, respectively, upon a change of p from 3.5 to 5.0. This dependence is found to be tightly correlated with the crystal field environment, as characterized by the local lattice distortion. This work sheds light onto an alternative strategy to enhance the UC luminescence in this FTTB family.
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DYES AND PIGMENTS
·
2013
·
IF 3.532
Zhengping Dong,Xin Tian,Yuanzhe Chen,Jingran Hou,Yueping Guo,Jian Sun,Jiantai Ma
A novel and simple fluorescent chemosensor based on rhodamine (R-2) is designed and synthesized to detect Hg 2+ . Probe R-2 exhibits high selectivity and sensitivity for sensing Hg 2+ with a detection limit at 10 −8 M level, and displays a significant color change from colorless to pink color in the presence of Hg 2+ . About a 400-fold increase in fluorescence emission intensity is observed upon binding excess Hg 2+ in 50% H 2 O/CH 3 CN HEPES buffer at pH 7.00. The titration results show a 1:1 complex formation between R-2 and Hg 2+ . The reversibility of chemosensor R-2 is verified through its spectral response toward Hg 2+ and I − titration experiments. Using Hg 2+ and I − as chemical inputs and the fluorescence intensity signal as outputs, R-2 can be utilized as an INHIBIT logic gate at molecular level.
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CELL BIOCHEMISTRY AND BIOPHYSICS
·
2014
·Vol. 71
·期 2
·971-976
·
IF 2.38
Zhou Yan,Gao Yuan,Chen Yingying,Zheng Rui,Zhang Wei,Tan Mingqi
The present research assessed the effects of lettuce glycoside B (LGB), a compound separated and purified from Pterocypsela
laciniata , on irradiation-induced pulmonary fibrosis and explored the mechanism involved. Animal model of irradiation exposure inducing pulmonary fibrosis was established by Co irradiator. Rats were intraperitoneally treated with LGB (100, 200 and 400 mg/kg) once per day for a month. Lung index data were analyzed. The levels of fibrosis were assessed by hydroxyproline (Hyp) of pulmonary and lung tissue sections after irradiation exposure. Alveolitis and fibrosis levels were calculated from semi-quantitative analysis of hematoxylin and eosin and Masson’s trichrome lung section staining. The serum levels of transforming growth factor β1 (TGF-β1), interleukin (IL)-6, and tumor necrosis factor-α (TNF-α) were also evaluated. Antioxidant enzymes of superoxide dismutase (SOD) were measured in serum. Moreover, we also measured serum malondialdehyde (MDA) levels, a marker of oxidative stress. Treatment with LGB significantly reduced mortality rates and lung index scores and MDA content, enhanced SOD and other antioxidant enzymes activity, and regulated serum levels of TGF-β1, IL-6, and TNF-α. These results demonstrated that LGB significantly inhibited irradiation-induced pulmonary fibrosis. Furthermore, the results suggested promising clinical effect of LGB therapies for treating irradiation-induced pulmonary fibrosis.
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COLLOID AND POLYMER SCIENCE
·
2014
·Vol. 292
·期 12
·3085-3093
·
IF 2.41
Huang Haibin,Chen Qinhui,He Junhui,Zheng Longhui,Chen Baoling,Lin Jinhuo
Janus materials with anisotropic chemical structures and physical properties have attracted increasing attention due to their diversified potential applications. In this paper, titanium dioxide/3-(trimethoxysilyl) propylmethacrylate (TiO 2 /MPS) was obtained by swelling assisted with extrusion of PS@TiO 2 . Then, the phenolic resin (PF) was coated on the surface of MPS lobe. Finally, TiO 2 /C Janus composite particles were obtained by sintering at the atmosphere of nitrogen. The middle objects during reactive process and the final product were systematically characterized. Results showed that the Janus porous particles of TiO 2 /C were snowman-like structure, in which the average diameter of the carbon lobe was 178 nm and that of TiO 2 lobe was 226 nm. When used as photocatalysts for Rhodamine B degradation in aqueous solution under UV irradiation, the resulted Janus product exhibited more efficient photocatalytic activity than TiO 2 hollow microspheres.
Schematic illustration of swelling polymerization approach to synthesize TiO 2 /C Janus composite particles and its photocatalytic activity for the degradation of rhodamine B
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Journal of Materials Chemistry A
·
2015
·Vol. 3
·期 14
·7568-7574
·
IF 7.443
Fang Liao,Xun Song,Siwei Yang,Chenyao Hu,Lin He,Shuai Yan,Guqiao Ding
We demonstrate a new semiconducting polymer dot: the poly(o-phenylenediamine)–Rhodamine B copolymer dot (Pp–RhB dot), which emits in the red wavelength range. The Pp–RhB dots can be used as an ultrasensitive fluorescence probe for NO2−in vivo and show high selectivity and ultrasensitivity (detection limit: 2.0 × 10−11 M) for NO2−. The fluorescence of Pp–RhB dots is decreased (φ = 0.014) as a result of fast photoinduced electron transfer (PET) between the modulator (poly(o-phenylenediamine)) and the transducer (RhB), but the N–NO2 bonding mode prevents PET, causing the fluorescence emission to be enhanced (φ = 0.92). This probe effectively avoids the influence of auto-fluorescence in biological systems and gave positive results when tested in both aqueous solution and living cells.
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APPLIED SURFACE SCIENCE
·
2015
·
IF 2.711
Jun Dai,Juan Yang,Xiaohan Wang,Lei Zhang,Yingjie Li
Wirelike catalysts of mixed-phase TiO 2 (B)/anatase TiO 2 , bare anatase TiO 2 and TiO 2 (B) are synthesized via calcining precursor hydrogen titanate obtained from hydrothermal process at different temperatures between 450 and 700 °C. Under visible light irradiation, mixed-phase TiO 2 (B)/anatase TiO 2 catalysts exhibit enhanced photocatalytic activity in comparison with pure TiO 2 (B) and anatase TiO 2 toward selective oxidation of benzylamines into imines and the highest photocatalytic activity is achieved by TW-550 sample consisting of 65% TiO 2 (B) and 35% anatase. The difference in photocatalytic activities of TiO 2 samples can be attributed to the different adsorption abilities resulted from their crystal structures and interfacial charge separation driven by surface-phase junctions between TiO 2 (B) and anatase TiO 2 . Moreover, the photoinduced charge transfer mechanism of surface complex is also proposed over mixed-phase TiO 2 (B)/anatase TiO 2 catalysts. Advantages of this photocatalytic system include efficient utilization of solar light, general suitability to amines, reusability and facile separation of nanowires catalysts.
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PHARMACEUTICAL RESEARCH
·
2013
·Vol. 31
·期 2
·291-304
·
IF 4.742
Yang Xiao-Li,Luo Yan-Ling,Xu Feng,Chen Ya-Shao
Purpose Block copolymer micelles are extensively used as drug controlled release carriers, showing promising application prospects. The comb or brush copolymers are especially of great interest, whose densely-grafted side chains may be important for tuning the physicochemical properties and conformation in selective solvents, even in vitro drug release. The purpose of this work was to synthesize novel block copolymer combs via atom transfer radical polymerization, to evaluate its physicochemical features in solution, to improve drug release behavior and to enhance the bioavailablity, and to decrease cytotoxicity. Methods The physicochemical properties of the copolymer micelles were examined by modulating the composition and the molecular weights of the building blocks. A dialysis method was used to load hydrophobic camptothecin (CPT), and the CPT release and stability were detected by UV–vis spectroscopy and high-performance liquid chromatography, and the cytotoxicity was evaluated by MTT assays. Results The copolymers could self-assemble into well-defined spherical core-shell micelle aggregates in aqueous solution, and showed thermo-induced micellization behavior, and the critical micelle concentration was 2.96–27.64 mg L −1 . The micelles were narrow-size-distribution, with hydrodynamic diameters about 128–193 nm, depending on the chain length of methoxy polyethylene glycol (mPEG) blocks and poly(N-isopropylacrylamide) (PNIPAM) graft chains or/and compositional ratios of mPEG to PNIPAM. The copolymer micelles could stably and effectively load CPT but avoid toxicity and side-effects, and exhibited thermo-dependent controlled and targeted drug release behavior. Conclusions The copolymer micelles were safe, stable and effective, and could potentially be employed as CPT controlled release carriers.
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FOOD CHEMISTRY
·
2014
·
IF 3.259
Ping Qi,Zhihao Lin,Jiaxu Li,ChengLong Wang,WeiWei Meng,Hong Hong,Xuewu Zhang
In this work, a simple, rapid and sensitive analytical method for the determination of rhodamine B in chili-containing foodstuffs is described. The dye is extracted from samples with methanol and analysed without further cleanup procedure by high-performance liquid chromatography (HPLC) coupled to fluorescence detection (FLD). The influence of matrix fluorescent compounds (capsaicin and dihydrocapsaicin) on the analysis was overcome by the optimisation of mobile-phase composition. The limit of determination (LOD) and limit of quantification (LOQ) were 3.7 and 10 μg/kg, respectively. Validation data show a good repeatability and within-lab reproducibility with relative standard deviations <10%. The overall recoveries are in the range of 98–103% in chili powder and in the range of 87–100% in chili oil depending on the concentration of rhodamine B in foodstuffs. This method is suitable for the routine analysis of rhodamine B due to its sensitivity, simplicity, reasonable time and cost.
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高影响因子
POLYMER
·
2016
·
IF 3.586
Qian He,Yali Yuan,Fengxia Chen,Zhi Ma,Xingqi Zhu,Rui Song
In this work, we systematically investigated the aggregation and confined crystallization behavior of polymethylene- b -poly acrylic acid diblock copolymers (PM- b -PAA, M 93 A 94 ) under the influence of polyethyene polyamine (PPA). With the increasing molar ratio of PPA, the morphologies of PM- b -PAA micelles experienced sphere-to-band-to-sheet transformations with regular changes of sizes on cooling from 80 °C mixed solution. Further investigation of the crystalline feature of PM- b -PAA indicated that the crystallization of PM block was profoundly restrained by PPA with the dual confinements, i.e., chemical and physical confinement which exerted through the hierarchical hydrogen bonding and 3D hydrogel network, respectively, in the mixed system. In particular, when the PPA and PM- b -PAA aqueous solution were mixed with equivalent volume, hydrogels was accessible. And rheology property indicated that the BCP/PPA-0.5 hydrogels hold the maximal storage modulus G′, and meanwhile the minimum loss tangent, tanδ.
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JOURNAL OF CHROMATOGRAPHY B-ANALYTICAL TECHNOLOGIES IN THE BIOMEDICAL AND LIFE SCIENCES
·
2016
·
IF 2.687
Zerong Long,Weiwei Xu,Yi Lu,Hongdeng Qiu
1 A new and facile rhodamine B (RhB)-imprinted polymer nanoshell coating for SiO 2 nanoparticles was readily prepared by a combination of silica gel modification and molecular surface imprinting. The RhB-imprinted polymers (RhB-MIPs) were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, and UV–vis spectroscopy; the binding properties and selectivity of these MIPs were investigated in detail. The uniformly imprinted nanoparticles displayed a rather thin shell thickness (23 nm) with highly effective recognition sites, showing homogenous distribution and monolayer adsorption. The maximum MIP adsorption capacity ( Q m ) was as high as 45.2 mg g −1 , with an adsorption equilibrium time of about 15 min at ambient temperature. Dynamic rebinding experiments showed that chemical adsorption is crucial for RhB binding to RhB-MIPs. The adsorption isotherm for RhB-MIPs binding could also be described by the Langmuir equation at different temperatures and pH values. Increasing temperature led to an enhanced Q m , a decreased dissociation constant ( K' d ), and a more negative free energy (Δ G ), indicating that adsorption is favored at higher temperatures. Moreover, the adsorption capacity of RhB was remarkably affected by pH. At pH > 7, the adsorption of RhB was driven by hydrogen bonding interactions, while at pH < 7 electrostatic forces were dominant. Additionally, the MIPs also showed specific recognition of RhB from the standard mixture solution containing five structurally analogs. This method was also successfully employed to determine RhB content in red wine and beverages using three levels of spiking, with recoveries in the range of 91.6–93.1% and relative standard deviations lower than 4.1%.
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JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY
·
2016
·
IF 3.035
Qianghua Ye,Fanyong Yan,Dechao Shi,Tancheng Zheng,Yinyin Wang,Xuguang Zhou,Li Chen
Nitrogen and boron co-doped carbon dots (BCNDs1–3) were prepared from three kinds of borate via a facile hydrothermal method . The as-prepared BCNDs did not shift with the change of excitation wavelength and possess good water dispersibility, strong fluorescence emission with high fluorescent quantum yield of 29.01%, 51.42%, 68.28%, respectively. Subsequently, these BCNDs were exploited as excellent Hg 2 + ion and 2,4,6-trinitrophenol (TNP) probe. The efficient selective detection of Hg 2 + can be attributed to non-radiative electron/hole recombination annihilation through an effective electron transfer process and the detection of TNP can be attributed to the fluorescence resonance energy transfer process (FRET). The results show that the BCNDs2 is the most sensitive fluorescence probe for Hg 2 + ions and TNP detection as low as Hg 2 + 7.3 nM and TNP 0.35 μM compared with BCNDs1 and BCNDs3. The as-prepared BCNDs possess the advantages of good selectivity, fast response and a broad linear detection. They were applied to sensing and imaging of human umbilical vein endothelial cells , showing low cytotoxicity and good biocompatibility .
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APPLIED SURFACE SCIENCE
·
2017
·
IF 3.387
Ruirui Hao,Guohong Wang,Chuanjia Jiang,Hua Tang,Qingchuan Xu
Semiconductor-based photocatalysis is a promising method for degradation of environmental pollutants, but the activity of most widely used photocatalysts such as titania (TiO 2 ) is still unsatisfactory under visible light. Herein, we synthesized a highly efficient visible-light-responsive heterojunction catalysts based on graphitic carbon nitride (g-C 3 N 4 ) and TiO 2 . The g-C 3 N 4 /TiO 2 heterojunction composites with high specific surface area were prepared via in situ hydrothermal synthesis followed by calcination , using titanium tetrachloride (TiCl 4 ) and melamine as precursors. Interesting, HCl from the hydrolysis of TiCl 4 served as the proton source to acidify the melamine. The g-C 3 N 4 /TiO 2 heterojunction composites exhibited higher photocatalytic performance for decomposition of Rhodamine B (RhB) than pure g-C 3 N 4 or TiO 2 under visible light irradiation. The high activity can be ascribed to the high specific surface area (up to 115.6 m 2 g −1 ) of the g-C 3 N 4 /TiO 2 composites and a synergistic heterojunction structure between TiO 2 and g-C 3 N 4 . Moreover, the photocatalytic performances of the g-C 3 N 4 /TiO 2 composites rely on the content of melamine in the synthesis precursors: with an optimum melamine content (3 g for 0.5 mL of TiCl 4 ), the sample showed the highest photocatalytic performance, which is superior to pure TiO 2 and g-C 3 N 4 by a factor of 18.7 and 3.5, respectively. Active species trapping experiments revealed that superoxide radicals and photogenerated holes played crucial roles in the photocatalytic reactions. The results will provide new ideas for the smart design and development of g-C 3 N 4 -based highly active photocatalysts with ultrahigh specific surface area for environmental and energy applications.
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