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Zhang Z.,Shanghai Key Laboratory of Modem Metallurgy and Materials Processing | Zhang Z.,Linyi Normal University | Gu S.,Technical Center for Animal Plant and Food Inspection and Quarantine | Ding Y.,Shanghai Key Laboratory of Modem Metallurgy and Materials Processing | And 2 more authors.
Biosensors and Bioelectronics | Year: 2014

A mild and novel preparation tactics based on electrochemical techniques for the fabrication of electro-deposited graphene (E-GR) and polymerized β-cyclodextrin (P-βCD) nanocomposite film were developed. The structure and morphology of GR-based nanocomposite were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy. Simultaneously, the electrochemical properties of this nanocomposite were characterized by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Based on the synergistic effect of E-GR and P-βCD, a super-sensitive electrochemical sensor for quercetin was successfully fabricated. Under optimum conditions, the determination range for quercetin was from 0.005 to 20. μM with a low detection limit of 0.001. μM (S/. N=3). Moreover, this sensor also displays excellent sensitivity, fine reproducibility and stability. To further study the practical applicability of the proposed sensor, the determination of real samples was carried out with satisfactory results. © 2014 Elsevier B.V.

Yin C.,Zhejiang University | Yin C.,Nanjing Agricultural University | Shen G.,Nanjing Agricultural University | Guo D.,Zhejiang University | And 14 more authors.
Nucleic Acids Research | Year: 2016

The genomes and transcriptomes of hundreds of insects have been sequenced. However, insect community lacks an integrated, up-to-date collection of insect gene data. Here, we introduce the first release of InsectBase, available online at http://www.insect-genome.com. The database encompasses 138 insect genomes, 116 insect transcriptomes, 61 insect gene sets, 36 gene families of 60 insects, 7544 miR-NAs of 69 insects, 96 925 piRNAs of Drosophila melanogaster and Chilo suppressalis, 2439 lncRNA of Nilaparvata lugens, 22 536 pathways of 78 insects, 678 881 untranslated regions (UTR) of 84 insects and 160 905 coding sequences (CDS) of 70 insects. This release contains over 12 million sequences and provides search functionality, a BLAST server, GBrowse, insect pathway construction, a Facebook-like network for the insect community (iFacebook), and phylogenetic analysis of selected genes. © The Author(s) 2015.

Wei X.,China Pharmaceutical University | Wei X.,Food Laboratory | Shen W.,Food Laboratory | Yu K.,Food Laboratory | And 8 more authors.
Chinese Journal of Chromatography (Se Pu) | Year: 2016

The gas chromatography-mass spectrometric (GC-MS) method with two different ionization techniques, electron impact (EI) and positive chemical ionization (PCI), have been developed for the simultaneous determination of three sterenes in olive oil. The olive oil sample was dissolved in petroleum ether, followed by cleanup on a silica gel column and finally analyzed by GC-EI/MS and GC-PCI/MS in selected ion monitoring mode. The quantitation was performed by internal standard calibration with cholesta-3, 5-diene as internal standard. These two methods were compared in terms of linearity, accuracy, precision and sensitivity. Good linearities were obtained with correlation coefficients (r) higher than 0.999 for campesta-3, 5-diene in the range of 0.024 to 0.48 mg/L, stigmasta-3, 5, 22-triene in the range of 0.02 to 0.50 mg/L and stigmasta-3, 5-diene in the range of 0.03 to 0.75 mg/L. The accuracy test was carried out at three spiked levels in extra virgin olive oil. The average recoveries ranged from 88.7% to 99.5% (EI) and 87.1% to 109.2% (PCI), with relative standard deviations (RSDs, n=6) not higher than 8.3%. Limits of quantification (LOQs, S/N=10) were 0.03 mg/kg (EI) and 0.03-0.10 mg/kg (PCI). Comparative analysis showed a large number of fragment ions could be obtained in EI mode while quasi-molecular ions or other adduct molecular ions were the most abundant ion formed in the PCI mode. Besides, PCI has a better selectivity than EI when applied to real samples. In conclusion, these two ionization techniques are complementary and alternative in the routine analysis of sterenes in olive oil.

Gu S.,Shanghai University | Gu S.,Technical Center for Animal Plant and Food Inspection and Quarantine | Lu Y.,Shanghai University | Ding Y.,Shanghai University | And 4 more authors.
Biosensors and Bioelectronics | Year: 2014

We describe a droplet-based microfluidic electrochemical sensor using platinum-black (Pt-black) microelectrode. Pt-black microelectrode was generated by electrodeposition of Pt nanoparticles on bare Pt microelectrode. Scanning electron microscope (SEM) image displays a flower-like microstructure of Pt nanoparticels. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) indicate that the Pt-black efficiently decreased the charge transfer resistance and improved the electrocatalytic activity towards oxidation of hydrogen peroxide (H2O2). Compared with bare Pt microelectrode, the current response on Pt-black microelectrode increased 10.2 folds. The effect of applied potential and electrodeposition time has been investigated in detail. The proposed sensor was validated by performing enzyme activity assay in flowing droplets. For demonstration, glucose oxidase (GOx) is chosen as the model enzyme, which catalyzes the oxidation of β-d-glucose to the product H2O2. The enzyme activity of GOx was evaluated by measuring the electrochemical current responding to various glucose concentrations. And the results indicate that this microfluidic sensor holds great potential in fabricating novel glucose sensors with linear response up to 43.5mM. The analytical applications of the droplet-based microfluidic sensor were tested by using human blood serum samples. Reproducibility, interferences, and long-term stability of the modified electrode were also investigated. The present approach shows the feasibility and great potentials in constructing highly sensitive and low-consumption sensors in the field of droplet microfluidics. © 2013.

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