UV-Light Photoelectrochemical Sensor Based on the Copper Tetraamino-Phthalocyanine-modified ITO Electrode for the Detection of Nifedipine in Drugs and Human Serum

Jinyun Peng,Wenfeng Zhuge,Yingying Huang,Cuizhong Zhang,Wei Huang 대한화학회 2019 Bulletin of the Korean Chemical Society Vol.40 No.3

In this study, a new photoelectrochemical (PEC) sensor based on the copper tetraamino-phthalocyanine-modified ITO electrode (CuTAPc/ITO) was designed for the determination of nifedipine. The prepared CuTAPc materials were characterized using UV?Visible spectrophotometry (UVS), Fourier transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD). Then, the CuTAPc solution was coated on the ITO electrode surface to fabricate a simple PEC sensing platform. Then, the photoelectrochemical behavior of nifedipine at the CuTAPc/ITO electrode was investigated by chronoamperometry under ultraviolet light irradiation. The obtained results indicated that the modified electrode showed a higher response signal than the blank electrode. The photocurrent of CuTAPc/ITO increased with the increasing concentration of nifedipine. The peak photocurrents were linearly dependent on the nifedipine concentration in the range of 0.25?18.0 ?mol/L, thereby providing the detection limit of 0.15 ?mol/L (S/N = 3). Due to the good responses for the determination of nifedipine, this sensor can be used as an alternative analysis tool for the detection of nifedipine in various real samples with high sensitivity, low detection limit, and wide linearity range.

Expression, purification and enzymatic properties of a β-Nacetylhexosaminidase from brown planthopper, Nilaparvata lugens

Yunhua Zhang,Jinyun Ji,Xiao Zhao,Ruoheng Jin,Jian Hong Li,Hu Wan 한국응용곤충학회 2017 Journal of Asia-Pacific Entomology Vol.20 No.4

A previous study demonstrated that a β-N-acetyl-D-hexosaminidase (NlHex4) from the brown planthopper could serve as a new potential target for biopesticides due to its requirement for molting, and lethal phenotypes were observed via RNA interference. However, the enzymatic properties of NlHex4 remain unclear. In the present study, NlHex4 was expressed, purified and characterized. Recombinant NlHex4 was functionally expressed in baculovirus-infected insect cells and purified with a molecular weight of approximately 70 kDa. Recombinant NlHex4 had an optimal pH and temperature of 6.0 and 60 °C, respectively. Moreover, recombinant NlHex4 exhibited thermal stability at 50 °C for at least 1 h. Furthermore, the activity of recombinant NlHex4 was inhibited by the metal ions Fe2+ and Fe3+ and the serine protease inhibitor phenylmethanesulfonyl fluoride. These results reveal the enzymatic properties of NlHex4 and provide a basis for future investigation of the interaction between HEX and chitin oligosaccharide.

Molecular cloning and characterization of a phenylalanine hydroxylase from the common cutworm Spodoptera litura☆

Yashu Zhang,Xiao Zhao,Jinyun Ji,Tinghao Kang,Jian Hong Li,Hu Wan 한국응용곤충학회 2016 Journal of Asia-Pacific Entomology Vol.19 No.2

In the present study, a phenylalanine hydroxylase (PAH) was cloned and characterized from the common cutworm Spodoptera litura (SlPAH). The SlPAH gene is an 1863 bp full-length cDNAwith a 1371 bp open reading frame that encodes a predicted 52.35 kDa protein of 457 amino acid residueswith an isoelectric point of 5.39. The SlPAH gene contains 6 exons and 5 introns. A multiple sequence analysis of SlPAH showed an 88–68% sequence identity to Papilio xuthus PAH and other insect PAHs. A phylogenetic tree revealed that SlPAH is a novel member of the PAH family. Tissue distribution analyses indicated that SlPAH is constitutively expressed in the epidermis, midgut, and fat body, with the highest expression occurring in the fat body on days 2 and 3 of the sixth-instar larval stage and day 1 of the prepupa stage. However, RNAi-mediated SlPAH gene silencing had no observable phenotype in S. litura larvae. Additionally, SlPAH expression is acutely up-regulated in the fat body after injection with Bacillus thuringiensis, Escherichia coli, or Beauveria bassiana. Therefore, these results provide a molecular basis for the functional roles of SlPAH during development and the innate immune response in S. litura.

Manganese dioxide-graphene nanocomposite film modified electrode as a sensitive voltammetric sensor of indomethacin detection

Yuxia Liu,Zhenfa Zhang,Cuizong Zhang,Wei Huang,Caiyun Liang,Jinyun Peng 대한화학회 2016 Bulletin of the Korean Chemical Society Vol.37 No.8

Excess amount of analgesic and anti-inflammatory drug, such as indomethacin, often leads to serious gastrointestinal complications; therefore, amount of such active compound should be regulated in commercial drugs. This study proposes an efficient analytical technique to detect indomethacin selectively. We prepared and investigated electrochemical properties of a manganese dioxide-graphene nanocomposite film modified glassy carbon electrode (MnO2-Gr/GCE). The behavior of the modified electrode as electrocatalyst towards indomethacin oxidation was also examined. The cyclic voltammetric results reveal that the electrocatalytic activity for the oxidation of indomethacin can significantly be enhanced on the MnO2-Gr/GCE. Indomethacin exhibited a sensitive anodic peak at about 0.90 V at MnO2-Gr/GCE. The data obtained from differential pulse voltammetry showed that the anodic peak currents were linearly dependent on the indomethacin concentrations in the range of 1.0 × 10−7 to 2.5 × 10−5 mol/L with a detection limit of 3.2 × 10−8 mol/L (S/N = 3). Most importantly, the proposed method shows efficient and selective sensing of indomethacin in commercial pharmaceutical formulations. This is the first report of a voltammetric sensor for indomethacin using MnO2-Gr/GCE. We believe that this new method can be commercialized for routine applications in laboratories.

Enhancing the insecticidal activity of recombinant baculovirus by expressing a growth-blocking peptide from the beet armyworm Spodoptera exigua

Hu Wan,Yashu Zhang,Xiao Zhao,Hong You,Jian Hong Li,Jinyun Ji 한국응용곤충학회 2015 Journal of Asia-Pacific Entomology Vol.18 No.3

Insect cytokine growth-blocking peptides (GBPs) play functional roles in growth regulation and the innate immune response.Moreover, high concentrations of GBPs significantly induce larvalmorphological abnormalities and lethality. In the present study, a recombinant AcNPV, AcNPV-SeGBPm, expressing a growth-blocking peptide fromthe beet armywormSpodoptera exigua (SeGBP) under the control of a polyhedrin promoterwas constructed. Western blot analysis indicated that the mature peptide of SeGBP (SeGBPm) is expressed as a 3-kDa peptide in recombinant baculovirus-infected Sf9 insect cells. SeGBPm expression in Sf9 insect cells decreased cell viability significantly and induced apoptotic cell death. In addition, the body weights of S. exigua larvae inoculated with AcNPV-SeGBPm decreased significantly compared to those of larvae inoculated with wild-type AcNPV. Moreover, AcNPV-SeGBPm improved the rate of larvae killing (LT50) by approximately 1 day compared to wild-type AcNPV. Taken together, the obtained data demonstrate the great potential for future investigations of growth-blocking peptides for use as biopesticides.

A Trellis-based Technique for Blind Channel Estimation and Equalization

Lei Cao,Chang Wen Chen,Philip Orlik,Jinyun Zhang,Daqing Gu 한국통신학회 2004 Journal of communications and networks Vol.6 No.1

A Trellis-based Technique for Blind Channel Estimation and Equalization

Cao, Lei,Chen, Chang-Wen,Orlik, Philip,Zhang, Jinyun,Gu, Daqing The Korea Institute of Information and Commucation 2004 Journal of communications and networks Vol.6 No.1

In this paper, we present a trellis-based blind channel estimation and equalization technique coupling two kinds of adaptive Viterbi algorithms. First, the initial blind channel estimation is accomplished by incorporating the list parallel Viterbi algorithm with the least mean square (LMS) updating approach. In this operation, multiple trellis mappings are preserved simultaneously and ranked in terms of path metrics. Equivalently, multiple channel estimates are maintained and updated once a single symbol is received. Second, the best channel estimate from the above operation will be adopted to set up the whole trellis. The conventional adaptive Viterbi algorithm is then applied to detect the signal and further update the channel estimate alternately. A small delay is introduced for the symbol detection and the decision feedback to smooth the noise impact. An automatic switch between the above two operations is also proposed by exploiting the evolution of path metrics and the linear constraint inherent in the trellis mapping. Simulation has shown an overall excellent performance of the proposed scheme in terms of mean square error (MSE) for channel estimation, robustness to the initial channel guess, computational complexity, and channel equalization.