JOURNAL OF POLYMER RESEARCH
·
2014
·Vol. 21
·期 12
·1-8
·
IF 1.897
Dang Xiaofei,Li Qian,Li Huayi,Yang Yuan,Zhang Liaoyun,Hu Youliang
Four new diester compounds were prepared and used as internal donors (ID) to prepare MgCl 2 supported titanium catalysts. Different diesters had notable influences on the porosity and the specific surface areas of the catalysts. The propylene polymerizations results showed that isopropyl groups(ID-2), cyclopentyl(ID-4) were more suitable substituents for diester compounds to replace phenyl(DIBP). The effects of different external donor (ED), Si/Ti ratio and hydrogen response on new ID precatalysts were evaluated by propylene polymerization.
✓ 已验证
产品关联
DOI
高影响因子
FIBERS AND POLYMERS
·
2014
·Vol. 15
·期 11
·2238-2246
·
IF 1.113
Zhou Qing,Li Mengxing,Yao Xiaohong,Lian Zhouyang,Zhang Chao,Wei Wuji,Huang Jian
To prepare polypropylene (PP) melt-blown fibers with Pb 2+ adsorption ability in water, high-crystalline PP was first pretreated by quenching and then grafted with acrylic acid (AA) by the suspension-grafting method to prepare PP grafted with AA (PP-g-AA). Finally, the chelating fiber, PP-g-AA-DETA, was prepared by the amidation of PP-g-AA fiber, obtained by melt-blown spinning, with diethylenetriamine (DETA). In the quenching pretreatment, the effects of solvent amount on the crystallinity and specific surface area of PP were investigated. The main factors of suspension grafting affecting the PP-g-AA graft rate were investigated, and the melt flow rate (MFR) and water contact angle (WCA) of PP-g-AA were measured. The maximum Pb 2+ adsorption ability of the chelating fiber was determined. The results indicate that the quenching pretreatment increased the size of PP amorphous area and formed pores on the particle surface. The specific surface area of PP and its crystallinity increased simultaneously with increasing solvent amount. The graft rate of PP-g-AA first increased with increasing solvent amount and then deceased. The MFR decreased rapidly after the graft rate reached 13 %, and the WCA dropped from 102 ° to 50 °. The adsorption behavior of the chelating fiber matched the Langmuir adsorption isotherm model and showed good selective Pb 2+ adsorption ability with Mg 2+ as competing ion. The maximum adsorption capacities of PP-g-AA and PP-g-AA-DETA fiber calculated by the Langmuir equation were 12.2 and 25.7 mg/g respectively.
✓ 已验证
DOI
高影响因子
JOURNAL OF NANOPARTICLE RESEARCH
·
2014
·Vol. 16
·期 12
·1-11
·
IF 2.278
Huang Xiao,Wang Zhen,Dai Hong,Wang Chunmei,Xia Bing,Chen Lan,Pan Jun
Although urethral carcinoma has a low incidence, it suffers from a poor curative rate for the low retention of medicine around urethra. In the present study, we developed a kind of magnetic targeting perfusion chemotherapy to detain the chemotherapeutic drugs. Docetaxel (TXT) grafted magnetic nanoparticles, of which size was around 40 nm, were obtained by the conjugation of TXT to amino-functionalized iron oxide (NH 2 @Fe 3 O 4 ). They have shown great potential to be targeted to and stayed in desired position of urethra under the externally applied magnetism through in vitro mimic urethral study. Furthermore, they have validly inhibited the growth of direct-contacted human urethral squamous carcinoma cells in vitro (up to 56.34 %) by the combination effects of TXT and NH 2 @Fe 3 O 4 , however, less than 3 % of TXT released from the nanoparticles, which was very few to impair the adjacent normal cells and tissues. Therefore, this kind of novel agentia was expected to hold great potential in clinic urethral carcinoma therapy.
✓ 已验证
产品关联
DOI
高影响因子
Journal of Pharmaceutical Innovation
·
2014
·Vol. 10
·期 1
·13-20
·
IF 1.25
Kong Lijun,Hu Jinxia,Qin Dan,Yan Peng
Combined techniques like fluorescence, circular dichroism (CD), and Fourier transform infrared (FT-IR) were applied to study the interaction between ifosfamide-loaded superparamagnetic iron oxide nanoparticles (ISION) and human serum albumin (HSA) at physiological pH. The fluorescence results showed the existance of a static quenching mode for HSA-ISION interaction. The binding constant at 298 K was in the order of 10 5 M −1 , showing high affinity occurred between ISION and HSA. The thermodynamic parameters obtained at three different temperatures (288, 298, and 308 K) indicated that the dominant binding forces are the electrostatic forces, for the values of the enthalpy change (Δ H °) and entropy change (Δ S °) were found to be −1.31 × 10 4 J · mol −1 and 55.4 J · mol −1 · K −1 , respectively. Fluorescence resonance energy transfer (FRET) analysis revealed that the average binding distance ( r ) between Trp of HSA and ISION was 5.25 nm. The results of CD and FT-IR spectra demonstrated that the secondary structure of HSA was altered in the presence of ISION.
✓ 已验证
产品关联
DOI
高影响因子
CELLULOSE
·
2014
·Vol. 22
·期 1
·203-214
·
IF 3.033
Qin Wang,Li Zhijun,Li Jixiang,Zhang Lihua,Liu Ruilai,Liu Haiqing
Two types of photochromic azobenzene hydroxypropyl celluloses (azo-HPCs) are prepared by homogeneous etherification of HPC with 4-(2,3-epoxypropoxy)-azobenzene and bromoethoxy-azobenzene in N,N -dimethylacetamide under mild conditions. The degree of substitution of azo moiety of azo-HPCs is tuned in the range of 0.6–1.8 by adjusting the mole ratio of azobenzene to HPC. Their chemical structures and properties are characterized by elemental analysis, infrared spectroscopy, nuclear magnetic resonance, thermogravimetric analysis, and differential scanning calorimetry. Compared to other cellulose ethers and esters with glass transition temperature (T g ) of normally larger than 100 °C, the azo-HPC derivatives display very low T g of ca. 20–40 °C. The azobenzenoxy-ethoxy-HPC is a thermotropic liquid crystal which displays cholesteric texture at 165 °C while cooling from its isotropic melt. Their solutions show almost fully reversible trans – cis – trans transition upon alternating irradiation of UV and visible light.
✓ 已验证
产品关联
DOI
高影响因子
Electrocatalysis
·
2014
·Vol. 6
·期 2
·211-219
·
IF 2.089
Ouyang Lei,Miao Yuqing,Xu Lina,Xiao Mingshu,Liang Xiaocai,Li Weiwei,Yang Yang
Molecular self-assembly is an important aspect of bottom-up approaches for the nanofabrication of functional materials. The self-assembly of smaller-size units like ions has yet to be studied further. The self-adsorption of Bi III without applied potential and electrochemical deposition of Bi/Bi III were studied and compared through cyclic voltammetry. Both of them exhibit two pairs of redox peaks assigned to the (2 × 2)-Bi adlayer and incommensurate ( p × √3)-2 Bi adlayer. The adsorption of two Bi surface phases is related with the Bi salt concentration and adsorption time. Within a certain concentration or time range, the adsorption approaches to be saturated due to the surface limitation of self-adsorbed surface layers. The (2 × 2)-Bi adlayer firstly adsorbs to the active sites of Au where there is strong interaction between Bi and Au. With the increase of time, more Bi adsorbs onto the unoccupied sites of Au with a relatively weak interaction force to form a denser ( p × √3)-2 Bi layer. A new pair of redox peaks appears for the electrodeposition of the Bi/Bi III bulky layer which is easily stripped from the Au surface through a consecutive potential scan. Comparatively speaking, the adsorbed (2 × 2) and ( p × √3)-2 Bi adlayers are stable in the same potential scanning condition due to the strong interaction between the two surface Bi layers and the below Au atoms. Such a controllable self-adsorption of the Bi III ultrathin layer on foreign substrates exhibits a potential for the modification of materials in the size of ions.
✓ 已验证
产品关联
DOI
高影响因子
MICROCHIMICA ACTA
·
2014
·Vol. 181
·期 13
·1497-1503
·
IF 3.719
Su Shao,Sun Haofan,Xu Fei,Yuwen Lihui,Fan Chunhai,Wang Lianhui
An electrochemical glucose biosensor was developed by immobilizing glucose oxidase (GOx) on a glass carbon electrode that was modified with molybdenum disulfide (MoS 2 ) nanosheets that were decorated with gold nanoparticles (AuNPs). The electrochemical performance of the modified electrode was investigated by cyclic voltammetry, and it is found that use of the AuNPs-decorated MoS 2 nanocomposite accelerates the electron transfer from electrode to the immobilized enzyme. This enables the direct electrochemistry of GOx without any electron mediator. The synergistic effect the MoS 2 nanosheets and the AuNPs result in excellent electrocatalytic activity. Glucose can be detected in the concentration range from 10 to 300 μM, and down to levels as low as 2.8 μM. The biosensor also displays good reproducibility and long-term stability, suggesting that it represents a promising tool for biological assays.
A MoS 2 -based glucose sensor has been prepared by gold nanoparticles-decorated MoS 2 nanocomposite, which exhibited excellent electrocatalytic activity, reproducibility and long-term stability. It was applied to determine glucose concentration in human serum, suggest the sensor maybe promising for practical application.
✓ 已验证
产品关联
DOI
高影响因子
ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2014
·Vol. 406
·期 7
·1903-1908
·
IF 3.578
Qian Sihua,Lin Hengwei
A simple, inexpensive yet highly selective colorimetric indicator-displacement assay array for the simultaneous detection and identification of three important biothiols at micromolar concentrations under physiological conditions and in real samples has been developed in this work. With use of an array composed of metal indicators and metal ions, clear differentiation among cysteine, homocysteine and glutathione was achieved. On the basis of the colour change of the array, quantification of each analyte was accomplished easily, and different biothiols were identified readily using standard chemometric approaches (hierarchical clustering analysis). Moreover, the colorimetric sensor array was not responsive to changes with 19 other natural amino acids, and it showed excellent reproducibility. Importantly, the sensor array developed was successfully applied to the determination and identification of the three biothiols in a real biological sample.
A simple, inexpensive yet highly selective colorimetric indicator-displacement assay array for the simultaneous detection and identification of three important biothiols was developed in this work
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Food Analytical Methods
·
2014
·Vol. 7
·期 8
·1693-1702
·
IF 1.802
Yang Jinling,Li Yongxin,Gong Weilei,Wang Changqin,Liu Bencheng,Sun Chengjun
A novel microextraction method termed matrix liquid-phase dispersion extraction (MLPDE) was presented in this paper. This method was adopted for the extraction of preservatives including methylparaben, ethylparaben, propylparaben, butylparaben, isopropylparaben, and isobutylparaben from different solid food samples. The extracted analytes were subjected to high-performance liquid chromatography (HPLC) analysis immediately. In this method, the food sample (0.50 g) was added previously to a syringe and then rinsed with hot water (45 °C). Subsequently, 2 ml extraction solvent (methanol) was added into the syringe. After ultrasonic extraction, food sample was dispersed into the methanol phase and a cloudy suspension came into being. Under the pressure of the plunger, methanol carrying the target analytes passed through 0.45 μm membrane and 10.0 μl of the eluent was injected into HPLC system. The important parameters including temperature, pH and volume of water, extraction solvent and its volume, sodium chloride addition, sample weight, and ultrasonic time as well as matrix effect were investigated. Under the optimum conditions, recoveries of the studied preservatives ranged from 93.7 % to 107.9 %. The intra-day and inter-day precisions (relative standard deviations) were less than 5.16 % and 5.32 %, respectively. The linear ranges of the method were 0.947–400 mg/kg with the correlation coefficients of 0.9988 to 0.9999. The limits of detection were 0.285 to 1.122 mg/kg. MLPDE is a very simple, rapid, cheap, and efficient method for extraction of nonpolar organic compounds from solid food samples. The proposed method has been successfully applied to the separation and quantification of six parabens in different solid food samples.
✓ 已验证
产品关联
DOI
高影响因子
COLLOID AND POLYMER SCIENCE
·
2014
·Vol. 292
·期 5
·1061-1072
·
IF 2.41
Luo Yan-Ling,Yang Xiao-Li,Xu Feng,Chen Ya-Shao,Zhao Xu
pH-sensitive poly(methacrylic acid)- block -hydroxyl-terminated polybutadiene- block -poly(methacrylic acid) block copolymers were synthesized by atom transfer radical polymerization of t -butyl methacrylate and follow-up acidolysis. The copolymers can spontaneously assemble into stable and nearly spherical micelle aggregates in aqueous solution, with hydrodynamic diameters ( D
h
) from 51 to 92 nm and critical micelle concentration of 3.90–7.76 mg L −1 . Z eta potentials were found to be increased with increasing (monomer)/(initiator) molar ratios. A pH-dependent phase behavior is produced at approximately 5.4–5.6, as determined by D
h
and I
335 / I
332 fluorescence intensity ratios. The in vitro camptothecin (CPT) release was compositional and pH dependent, and the cumulative CPT release below pH 7.2 was higher than that in pH 7.4. They could inhibit the premature burst CPT release. The copolymer micelles were low in cytotoxicity even at a micellar concentration of 800 mg L −1 , and therefore they may be used as potential drug-delivery carriers.
ᅟ
✓ 已验证
产品关联
DOI
高影响因子
Nanoscale Research Letters
·
2014
·Vol. 9
·期 1
·1-8
·
IF 2.481
Song Yuan-Jun,Wang Mingliang,Zhang Xiao-Yang,Wu Jing-Yuan,Zhang Tong
Serving as shape control agent, polyvinyl pyrrolidone (PVP) has been widely used in chemical synthesis of metal nanoparticles. However, the role of molecular weight (MW) of PVP has been rarely concerned. In this study, we show a facile method to control the shapes of silver nanocrystals using PVP with different MWs. PVP MW=8,000 , PVP MW=29,000 , PVP MW=40,000 , and PVP MW=1,300,000 are compared in the present study. Surprisingly, high-yield silver rodlike nanostructures, nanospheres, and nanowires can be obtained under the same growth environment and reactant concentrations by simply changing the MW of PVP. The mechanism studies of the role of PVP with different MWs in the growth process were carried out systemically using the morphology and spectroscopic measurement, FT-IR spectrum analysis, and seed crystallization monitoring. The results indicate that the MW of PVP plays a determinant role in the morphology and optical property control of the silver nanocrystals. Meantime, the concentration of PVP was found to be an assistant factor to further improve the shape and the yield of the synthesized nanocrystals.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2014
·Vol. 21
·期 7
·5217-5226
·
IF 2.757
Peng Na,Wang Kaifeng,Liu Guoguang,Li Fuhua,Yao Kun,Lv Wenying
Beta blockers are widely used pharmaceuticals that have been detected in the environment. Interactions between beta blockers and dissolved organic matter (DOM) may mutually alter their environmental behaviors. To assess this potential, propranolol (PRO) was used as a model beta blocker to quantify the complexation with DOM from different sources using the fluorescence quenching titration method. The sources of studied DOM samples were identified by excitation–emission matrix spectroscopy (EEMs) combined with fluorescence regional integration analysis. The results show that PRO intrinsic fluorescence was statically quenched by DOM addition. The resulting binding constants (log K
oc ) ranged from 3.90 to 5.20, with the surface-water-filtered DOM samples claiming the lower log K
oc and HA having the highest log K
oc . Log K
oc is negatively correlated with the fluorescence index, biological index, and the percent fluorescence response ( P
i ,n ) of protein-like region ( P
I,n ) and the P
i ,n of microbial byproduct-like region ( P
II,n ) of DOM EEMs, while it is correlated positively with humification index and the P
i ,n of UVC humic-like region ( P
III,n ). These results indicate that DOM samples from allochthonous materials rich in aromatic and humic-like components would strongly bind PRO in aquatic systems, and autochthonous DOM containing high protein-like components would bind PRO more weakly.
✓ 已验证
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）