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Abstract: A highly sensitive and selective molecularly imprinted (MIP) sensor combined with magnetic molecularly imprinted solid phase extraction (MMISPE) was developed for the determination of dibutyl phthalate (DBP) in complex matrixes. The magnetic molecularly imprinted polymer (MMIP) was synthesized as solid phase extraction (SPE) sorbet to extract DBP from complex matrixes and as sensing element to improve the selectivity of the imprinted sensor. The morphologies of MMIP and MIP-sensor were characterized by using scanning electron microscope (SEM) and transmission electron microscopy (TEM). The electrochemical performances of MIP-sensor were investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The conditions of preconcentration, elution and electrochemical determination were studied in detail. Under the optimized experimental conditions, the response currents of the MIP-sensor exhibited a linear relationship towards DBP concentrations ranging from 1.0×10−8 g/L to 1.0×10−3 g/L. The limit of detection of the MMIP-sensor coupled with the MMISPE was calculated as 0.052ng/L. The MMIP-sensor coupled with the MMISPE was applied to detect DBP in complex samples successfully. [Copyright &y& Elsevier]

ABSTRACT A new epoxy-ended hyperbranched polyether (HBPEE) with aromatic skeletons was synthesized through one-step proton transfer polymerization. The structure of HBPEE was confirmed by Fourier transform infrared spectroscopy (FTIR), and nuclear magnetic resonance (NMR) measurements. It was proved to be one high efficient modifier in toughening and reinforcing epoxy matrix. In particular, unlike most other hyperbranched modifiers, the glass transition temperature ( Tg) was also increased. Compared with the neat DGEBA, the hybrid curing systems showed excellent balanced mechanical properties at 5 wt % HBPEE loading. The great improvements were attributed to the increased cross-linking density, rigid skeletons, and the molecule-scale cavities brought by the reactive HBPEE, which were confirmed by dynamical mechanical analysis (DMA) and thermal mechanical analysis (TMA). Furthermore, because of the reactivity of HBPEE, the hybrids inclined to form a homogenous system after the curing. DMA and scanning electron microscopy (SEM) results revealed that no phase separation occurred in the DGEBA/HBPEE hybrids after the introduction of reactive HBPEE. SEM also confirmed that the addition of HBPEE could enhance the toughness of epoxy materials as evident from fibril formation. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1064-1073, 2013 [ABSTRACT FROM AUTHOR]

Diglycidyl ether of bisphenol A (DGEBA)/fluoro-terminated hyperbranched poly(phenylene oxide) (FHPPO) composites with improved mechanical and dielectric performances were prepared by blending a FHPPO with DGEBA. The low-polarity building blocks, abundant fluorinated terminal groups, and the inherent free volume brought by FHPPO efficiently lowered the dielectric constant and the dissipation factor. The free volumes of the cured DGEBA/FHPPO composites, which were quantified by positron annihilation lifetime spectroscopy, increased with the FHPPO loading. The moisture absorption of composites also decreased after the introduction of FHPPO due to the hydrophobicity of fluorinated substituents. Dynamic mechanical analysis tests and scanning electron morphology revealed that FHPPO phase separated from the composites during the curing process. The average diameter of dispersed FHPPO particles increased proportionally with the FHPPO loading. Composites with dispersed particle size of around 150 nm showed the best comprehensive mechanical performance. In addition, incorporation of FHPPO, which has lots of aromatic structures, into DGEBA also increased the thermal stabilities. POLYM. COMPOS., 34:1051-1060, 2013. © 2013 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Novel magnetic multi-walled carbon nanotubes@FeO molecularly imprinted polymers (MWNTs@FeO-MIPs) intended for bovine serum albumin (BSA) recognition were successfully developed. The MWNTs@FeO-MIPs were characterized with scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). Scanning electron microscopy images showed that the FeO nanoparticles (diameter: 50-60 nm) were coated with a layer of MIPs with an average thickness of 25-30 nm. The magnetic material was easily dispersed and retrieved through the application of an external magnetic field. Adsorption experiments showed that the estimated maximum amount of BSA that could be adsorbed onto the MWNTs@FeO-MIPs was 52.8 mg/g, and the time taken to reach equilibrium was about 40 min. Meanwhile, the MWNTs@FeO-MIPs exhibited excellent selectivity towards (i.e., recognition of) BSA. The feasibility of the use of the MWNTs@FeO-MIPs as a solid-phase extraction (SPE) sorbent was evaluated, and the results showed that the MWNTs@FeO-MIPs were able to separate the template protein BSA from a binary protein solution. The proposed sorbent based on MWNTs@FeO-MIPs for BSA separation exhibited satisfactory recoveries ranging from 92.0% to 97.3% in real samples. It was also successfully used for the purification of BSA from bovine calf serum. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

In this work, three pretreatment methods enzymatic hydrolysis, microwave treatment, and soaking with soluble soybean polysaccharides (SSPS) were employed to improve the cooking and eating quality of black rice. Meanwhile, the effects of three pretreatments on polyphenol content and antioxidant activity of black rice were evaluated. The results indicated that three pretreatments improved the textural properties, cooking quality and sensory scores of black rice, especially the enzymatic hydrolysis treatment showed excellent effects in improving the textural properties and cooking quality of black rice: the hardness/adhesion ratio decreased from 107.72 (control group) to 26.03; the soaking water absorption (SWA) rate increased from 7.76% (control group) to 20.63% at 20 min and increased from 25.85% (control group) to 35.60% at 120 min, respectively; the optimal cooking time (OCT) decreased from 30.3 min (control group) to 23 min; the cooking water absorption (CWA) rate increased from 227% (control group) to 284%, The above parameters were significantly different from the control group (p < 0.05). Simultaneously, most of the antioxidant activity of black rice was retained. In addition, there was an obvious change in the surface microstructure observed by scanning electron microscopy. [Display omitted] • Three pretreatment methods improved the textural properties and sensory scores of black rice. • Complex plant hydrolase showed the best effects in improving black rice's quality. • The antioxidant activity of pretreated black rice was still largely retained. • The cooking conditions of black rice were optimized. [ABSTRACT FROM AUTHOR]

Abstract: A novel sensitive and selective imprinted electrochemical sensor was successfully constructed for the direct detection of l -histidine by combination of a molecular imprinting film and multi-walled carbon nanotubes (MWNTs). The sensor was fabricated onto an indium tin oxide (ITO) electrode via stepwise modification of MWNTs and a thin film of molecularly imprinted polymers (MIPs) via sol–gel technology. The introduced MWNTs exhibited noticeable enhancement on the sensitivity of the MIPs sensor. Meanwhile, the molecularly imprinted film displayed high sensitivity and excellent selectivity for the target molecule l -histidine. The proposed imprinted sensor was characterized by using scanning electron microscope (SEM) and electrochemical methods involving cyclic voltammetry (CV), differential pulse voltammetry (DPV) and amperometric i–t curve. A linear ranging from 2.0μmolL−1 to 1.0mmolL−1 for the detection of l -histidine was observed with the detection limit of 5.8×10−9 molL−1 for S/N =3. This imprinted electrochemical sensor was successfully employed to detect l -histidine in human blood serum. [ABSTRACT FROM AUTHOR]

Abstract: ZnO/CdSe core-shell nanorod array films were synthesized via a two-step method. ZnO nanorod array films were first grown on a TCO substrate, and then CdSe nanocrystals were deposited on the nanorods to form core-shell structured films. The resulting films were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV–vis absorption spectroscopy. Especially, dark-field images and transmission electron diffraction of the TEM were used to study the morphology and the chemical nanostructure of the ZnO/CdSe core-shell nanorods in detail. We investigated the photovoltaic performance of the resulting ZnO/CdSe core-shell nanorod array films as solar cell photoanodes. Parameters, such as the length of the ZnO nanorods, the shell phase structure and the deposition time of the CdSe nanocrystals were found to affect the photovoltaic performance of the solar cell. This study provides a facile method to prepare nanocomposite photoanodes of solar cells, and gives some insight about the fundamental mechanisms that improve the performance. [Copyright &y& Elsevier]