NANOTECHNOLOGY
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2013
·Vol. 24
·期 14
·145101
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IF 3.842
Dao-Lu Tang,Fei Song,Cheng Chen,Xiu-Li Wang,Yu-Zhong Wang
Increasing attention has recently been paid to the fabrication of drug delivery systems with excellent cell internalization and intracellular drug release properties. In this study, an amphiphilic block copolymer of chitosan was synthesized for the first time, which can self-assemble into micelles in a neutral aqueous solution but partially disassemble in an acidic endosomal/lysosomal environment. The antitumor drug, camptothecin (CPT), was encapsulated in the cores of the micelles for tumor cell therapy. In vitro drug release studies demonstrated that the micelles presented a much faster release of CPT at pH 5.0 than at pH 7.4. Blank micelles were found to be nontoxic in preliminary in vitro cytotoxicity assays. Cell experiments showed that the CPT-loaded micelles could be effectively internalized by Hela cells and accomplished a potent antitumor cell efficacy, indicating that the chitosan-based micelles might be an attractive new platform for efficient intracellular drug delivery.
研究领域:
生物材料学
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药物递送系统
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肿瘤学
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产品关联
DOI
PubMed
高影响因子
Journal of Energy Chemistry
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2014
·
IF 0
Min Jiang,Dandan Zhu,Xuebo Zhao
Electrolysis of ammonia in alkaline electrolyte solution was applied for the production of hydrogen. Both Pt-loaded Ni foam and Pt-Ir loaded Ni foam electrodes were prepared by electrodeposition and served as anode and cathode in ammonia electrolytic cell , respectively. The electrochemical behaviors of ammonia in KOH solution were individually investigated via cyclic voltammetry on three electrodes, i.e. bare Ni foam electrode, Pt-loaded Ni foam electrode and Pt-Ir loaded Ni foam electrode. The morphology and composition of the prepared Ni foam electrode were analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Effects of the concentration of electrolyte solution and temperature of electrolytic cell on the electrolysis reaction were examined in order to enhance the efficiency of ammonia electrolysis. The competition of ammonia electrolysis and water electrolysis in the same alkaline solution was firstly proposed to explain the changes of cell voltage with the electrolysis proceeding. At varying current densities, different cell voltages could be obtained from galvanostatic curves. The low cell voltage of 0.58 V, which is less than the practical electrolysis voltage of water (1.6 V), can be obtained at a current density of 2.5 mA/cm 2 . Based on some experimental parameters, such as the applied current, the resulting cell voltage and output of hydrogen gas , the power consumption per gram of H 2 produced can be estimated.
研究领域:
能源科学
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催化化学
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产品关联
DOI
Journal of Energy Chemistry
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2014
·
IF 0
Yong Xie,Rui-Xia Yang,Nian-Yu Huang,Hua-Jun Luo,Wei-Qiao Deng
We reported a bifunctional material, Cr-salen implanted conjugated microporous polymer (Cr-CMP), which is able to capture excellent CO 2 amounts and has a remarkable catalytic activity towards the cycloaddition reaction of CO 2 to epoxides forming cyclic carbonates at mild conditions without additional solvents. This heterogeneous Cr-CMP catalyst has a superior catalytic activity to its related homogeneous catalyst and can be reused more than ten times without a significant decrease in catalytic activity.
研究领域:
材料科学
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催化化学
✓ 已验证
产品关联
DOI
CHINESE JOURNAL OF CHEMICAL ENGINEERING
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2014
·
IF 0.872
Weina ZHU,Chun CHANG,Chen MA,Fengguang DU
The kinetics for production of ethyl levulinate from glucose in ethanol medium was investigated. The experiments were performed in various temperatures (433–473 K) and initial glucose concentrations (0.056–0.168 mol·L −1 ) with extremely low sulfuric acid as the catalyst. The results show that higher temperature can improve the conversion of glucose to ethyl levulinate, with higher yield of ethyl levulinate (44.79%, by mole) obtained at 473 K for 210 min. The kinetics follows a simplified first-order kinetic model. For the main and side reactions, the values of activation energy are 122.64 and 70.97 kJ·mol −1 , and the reaction orders are 0.985 and 0.998, respectively.
研究领域:
化学工程
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生物化学
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产品关联
DOI
高影响因子
CHINESE JOURNAL OF CATALYSIS
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2014
·
IF 1.552
Xianfeng Fu,Jianyong Zheng,Xiangxian Ying,Hongde Yan,Zhao Wang
A novel ultraviolet (UV) spectrophotometric method for evaluating lipase transesterification activity in organic solvents is described. The model reaction was lipase-catalyzed transesterification between p -nitrophenyl palmitate (pNPP) and n -butanol in n -hexane at 30 °C. The conversion of pNPP to p -nitrophenol was monitored by measuring UV absorbance changes at 310 nm. Seven commercial lipases were tested using this method, and the results were similar to those obtained using gas chromatography . The UV spectrophotometric method was used to investigate the kinetics of the Lipozyme TL IM-catalyzed reaction of pNPP, and the correlation between synthetic activity and biocatalyst concentration was determined. The method was also used to investigate the Lipozyme TL IM-catalyzed transesterification properties, namely solvent effect, acyl acceptor specificity, alcohol tolerance, optimum reaction temperature, and thermostability.
研究领域:
生物化学
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酶工程
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DOI
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
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2014
·
IF 0.872
Shimin KANG,Jie CHANG,Juan FAN
A carbon-based sulfonated catalyst was prepared by direct sulfonation and carbonization (in moderate conditions: 200 °C, 12 h) of red liquor solids, a by-product of paper-making process. The prepared sulfonated catalyst (SC) had aromatic structure, composed of carbon enriched inner core, and oxygen-containing (SO 3 H, COOH, OH) groups enriched surface. The SO 3 H, COOH, OH groups amounted to 0.74 mmol·g −1 , 0.78 mmol·g −1 , 2.18 mmol·g −1 , respectively. The fresh SC showed much higher catalytic activity than that of the traditional solid acid catalysts (strong-acid 732 cation exchange resin, hydrogen type zeolite socony mobile-five (HZSM-5), sulfated zirconia) in esterification of oleic acid. SC was deactivated during the reactions, through the mechanisms of leaching of sulfonated species and formation of sulfonate esters. Two regeneration methods were developed, and the catalytic activity can be mostly regenerated by regeneration Method 1 and be fully regenerated by regeneration Method 2, respectively.
研究领域:
化学工程
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催化科学
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产品关联
DOI
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
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2014
·
IF 0.872
Zhijian HE,Xiaomin WANG,Tian YAO,Hang SONG,Shun YAO
Four novel benzothiazolium ionic liquids with PF − 6 ([C 1 Bth][PF 6 ], [C 4 Bth][PF 6 ], [C 5 Bth][PF 6 ] and [C 6 Bth][PF 6 ]) were synthesized, and the rang of their melting points were determined between 358.35 K–424.05 K. The relationship of their melting points and the length of the straight alkyl chain on cation reflected ‘S’ type tendency. Then, the solubilities of the four ionic liquids in six lower alcohols (methanol, ethanol, 1-propanol, 2-propanol, 1-butanol and 2-methyl-1-propanol) were measured in the temperature rang of 253.15–383.15 K at atmospheric pressure with static analytical method, respectively. It was found that [C 6 Bth][PF 6 ] in all investigated ionic liquids had the largest solubility in six alcohols and the solubility of [C 4 Bth][PF 6 ] in methanol was very sensitive for temperature in 313.15–333.15 K, which was so-called “temperature-sensitivity”. This feature is of great significance to their application of catalyzing reaction or extraction process, and makes the recovery and reuse of ionic liquids (ILs) become easier. Moreover, the experimental solubility data were correlated with the modified Apelblat equation and λ h equation, respectively. It was found that the result of correlation using two divided temperature ranges was better than that of using the whole temperature range.
研究领域:
化学
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材料科学
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产品关联
DOI
高影响因子
Journal of Environmental Sciences
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2014
·
IF 1.922
Lijuan Gao,Shiqiang Wang,Xuefei Zhao
Humic acid superabsorbent polymer (P(AA/AM-HA)) and superabsorbent polymer (P(AA/AM)) were synthesized by aqueous solution polymerization method using acrylic acid (AA), acrylamide (AM) and humic acid (HA) as raw material. The effects of N,N'-methylenebisacrylamide (MBA) crosslinking agent, potassium peroxydisulfate (KPS) initiator, reaction temperature, HA content, ratio of AA to AM, concentration of monomer and neutralization of AA on water absorption were investigated. Absorption and desorption ratios of nitrogen fertilizer and phosphate fertilizer were also investigated by determination of absorption and desorption ratio of NH 4 + , PO 4 3− on P(AA/AM-HA) and P(AA/AM). The P(AA/AM-HA) and P(AA/AM) were characterized by Fourier translation infrared spectroscopy, biological photomicroscope and scanning electron microscopy (SEM). The optimal conditions obtained were as follows: the weight ratio of MBA to AA and AM was 0.003; the weight ratio of KPS to AA and AM was 0.008; the weight ratio of HA to AA was 0.1; the mole ratio of AM to AA is 0.1; the mole ratio of NaOH to AA is 0.9; the reaction temperature was 60°C. P(AA/AM-HA) synthesized under optimal conditions, has a good saline tolerance, its water absorbency in distilled water and 0.9 wt.% saline solution is 1180 g/g and 110 g/g, respectively. P(AA/AM-HA) achieves half saturation in 6.5 min. P(AA/AM-HA) is superior to P(AA/AM) on absorption of NH 4 + , PO 4 3− . The SEM micrograph of P(AA/AM-HA) shows a fine alveolate structure. The biological optical microscope micrograph of P(AA/AM-HA) shows a network structure. Graft polymerization between P(AA/AM) and HA was demonstrated by infrared spectrum. The P(AA/AM-HA) superabsorbent has better absorbing ability of water and fertilizer, electrolytic tolerance and fewer cost than P(AA/AM) superabsorbent.
研究领域:
农业科学
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材料科学
✓ 已验证
DOI
PubMed
高影响因子
CHINESE JOURNAL OF CATALYSIS
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2014
·
IF 1.552
Wenju Wang,Huiling Li,Junli Ren,Runcang Sun,Jie Zheng,Guangwei Sun,Shijie Liu
An efficient homogeneous catalytic process was developed for the dehydration of xylose to furfural using inorganic salts as catalysts in a water/dimethyl sulfoxide (DMSO) system under mild condition. The effects of the types of inorganic salts were compared. The results showed that chlorides had higher catalytic performance than other salts, and SnCl 4 was the most effective chloride. The catalytic activity of paired SnCl 4 /LiCl catalysts was much higher than that of the single salt, and when the distribution coefficient ( χ SnCl4 ) was 0.8, the maximum furfural yield was 56.9%. The effects of the reaction conditions on the furfural yield were also investigated. The highest furfural yield, 63.0%, was achieved at 130 °C for 6 h under the optimized reaction conditions.
研究领域:
化学工程
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生物化工
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产品关联
DOI
高影响因子
Chinese Journal of Natural Medicines
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2014
·
IF 0
Pei-Pei WANG,Guo-Wei ZHAO,Wen XIA,En-Ji HAN,Lan XIANG
This study was conducted to investigate the chemical constituents of Piper wallichii (Miq.) Hand.-Mazz. and evaluate their biological activity. Compounds were isolated by various column chromatographic methods, and their structures were elucidated on the basis of physical characteristics and spectral data. The 1, 1-diphenyl-2-picrylhydrazyl (DPPH)-scavenging activity and acetylcholinesterase (AChE)-inhibitory activity of the compounds were evaluated. Five compounds were obtained and identified as 8- C -β-D-glucopyranosylkaempferol-3- O -β-D-glucopyranoside ( 1 ), 1, 2-dihydro-6,8-dimethoxy-7-hydroxy-1-(3, 5-dimethoxy-4-hydroxyphenyl)- N 1 , N 2 -bis-[2-(4-hydroxyphenyl)ethyl]-2, 3-naphthalene dicarboxamide ( 2 ), goniothalactam ( 3 ), aristololactam A IIIa ( 4 ) and piperlonguminine ( 5 ). Compound 1 was a new flavonol C -glycoside, 2 was a rare lignanamide, which was isolated from the family Piperaceae for the first time, and compound 3 was isolated from this plant for the first time. Among them, 2 showed potent DPPH-scavenging activity, with IC 50 of 31.38 ± 0.97 μmol·L −1 ; Compounds 2 , 3 , and 4 showed AChE inhibitory activity at 100 μmol·L −1 , with inhibition rates of 28.57% ± 1.47%, 18.48% ± 2.41% and 17.4% ± 3.03%, respectively.
研究领域:
植物化学
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药理学
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产品关联
DOI
PubMed
Journal of Energy Chemistry
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2014
·
IF 0
Delong Ma,Zhong Wu,Zhanyi Cao
Supercapacitors (SCs) have attracted much attention as one of the alternative energy devices due to their high power performance, long cycle life, and low maintenance cost. Graphene is considered as an innovative and promising material due to its large theoretical specific surface area, high electrical conductivity , good mechanical properties and chemical stability. Herein, we report an effective strategy for elaborately constructing rationally functionalized self-standing graphene (SG) obtained from giant graphene oxide (GGO) paper followed by an ultrarapid thermal-processing. This treatment results in both the exfoliation of graphene sheets and the reduction of GGO by elimination of oxygen-containing groups. The as-prepared SG electrode materials without additive and conducting agent provide an excellent combination of the electrical double layer capacitor (EDLC) and pseudocapacitor (PC) functions and exhibit superior electrochemical performance, including high specific capacitance, good rate capability and excellent cycling stability when investigated in three-electrode electrochemical cells .
研究领域:
材料科学
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能源存储
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产品关联
DOI
CHINESE JOURNAL OF ANALYTICAL CHEMISTRY
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2014
·
IF 0.7
Wei-Wei WANG,Yu QIU,Shao-Peng ZHANG,Jia-Wei LI,Xiao-Quan LU,Xiu-Hui LIU
A novel hydrogen peroxide sensor was fabricated by the seed-mediated growth method. Firstly, polyethyleneimine (PEI) functionalized multiwalled carbon nanotubes (MWNTs) were used as growth scaffold on a glass carbon electrode (GCE). Then, Au nanoparticles were uniformly electrodeposited as seeds. Finally, Pt nanoparticles (PtNPs) grew on Au PtNPs to form Pt@Au core-shell structure nanocomposite. A new type of electrochemical sensor based on Pt@Au/PEI-MWNTs nanocomposites for detection of hydrogen peroxide was then developed, and the designed Pt@Au/PEI-MWNTs/GCE was characterized by electrochemical methods and field emission scanning electron microscopy (FESEM). The differential pulse experiment results showed that the modified electrode exhibited excellent electrocatalytic activity towards the reduction of H 2 O 2 with the wide linear range from 9.2×10 −8 to 1.3×10 −3 M. The correlation coefficient was 0.9994 and the detection limit was down to 3.1×10 −8 M at the signal-to-noise ratio of 3.
研究领域:
分析化学
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纳米材料科学
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电化学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）