Molybdenum Trioxide Dihydrate-Graphene Composite for Electrochemical Detection of Thiourea Molecule

Xinmeng Zhang,Kezhi Li,Hejun Li,Jinhua Lu,Leilei Zhang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2016 NANO Vol.11 No.3

A novel electrochemical sensing platform was constructed based on a facile self-assembly procedure synthetic laminar molybdenum trioxide dihydrate (MoO3 · 2H2O)-graphene composite. Field emission scanning electron microscopy (FESEM), X-ray spectroscopy, X-ray diffraction (XRD) and Raman spectroscopy were employed to characterize the morphology and composition of the MoO3 · 2H2O-graphene composite. As a model molecule, thiourea was utilized to investigate the electrochemical behaviors of the MoO3 · 2H2O-graphene composite modified glass carbon electrode. The results show that the composite modified electrode has higher electron transfer rate than that of graphene modified electrode and bare glass carbon electrode meanwhile the peak currents of it has a good linear relationship with thiourea concentrations in the range of 2.40 X 10-3 − 19.3 X 10-3 M (R = 0.998) with detection limit of 4.99 µM (S/N = 3). This novel electrochemical sensor exhibits a higher absorption capacity (3.87 X 10-8 mol/cm2 ), a good reproducibility (1.41% relative standard deviation (RSD)), excellent anti-interference and a high stability. These excellent electrochemical properties of the MoO3 · 2H2O-graphene composite are attributed to the loose and porous structure and the synergistic effects between graphene and MoO3 · 2H2O, which make this composite material hold great potential applications for electrochemical sensor.

Identification and Screening of Gene(s) Related to Susceptibility to Enterotoxigenic Escherichia coli F4ab/ac in Piglets

Li, Hejun,Li, Yuhua,Qiu, Xiaotian,Niu, Xiaoyan,Liu, Yang,Zhang, Qin Asian Australasian Association of Animal Productio 2008 Animal Bioscience Vol.21 No.4

In 2004, Jorgensen and coworkers proposed the MUC4 gene as a candidate gene of enterotoxigenic Escherichia coli (ETEC) F4ab/ac receptor in piglets and a mutation of $G{\rightarrow}C$ in intron 7 of MUC4 was identified to be associated with the ETEC F4ab/ac adhesion phenotypes. In this study, we used 310 piglets of three breeds (Landrace, Large White and Chinese Songliao Black) to analyze the relationship between this mutation and the F4ab/ac adhesion phenotype. The results show that the genotypes at this site and the ETEC F4ab/ac adhesion phenotypes were not completely consistent, although they are very strongly associated. Among the individuals with genotype CC, which was identified as a resistant genotype to F4ab/ac adhesion, only 72.1% (124/172) were non-adhesive to ETEC F4ab and 77.9% (134/172) were non-adhesive to ETEC F4ac infections. This suggests that this mutation may not be the causative mutation for ETEC F4ab/ac adhesion, rather, the actual causative mutation may be in another gene closely linked to MUC4, or at aother site within the MUC4 gene. Our results also suggest that the receptors of F4ab and F4ac may be determined by two different but closely linked loci. In order to screen other genes related to F4ab/ac adhesion in piglets, the mRNA profiles from six full sib piglets, of which three were adhesive to ETEC F4ab/ac and three non-adhesive, were analyzed by suppression subtractive hybridization (SSH). One up-regulated gene, Ep-CAM, was selected for further analysis based on its role in the intestinal epithelial cells adhesion. Using real-time RT-PCR, we found that the Ep-CAM gene was significantly up-regulated in the piglets adhesive to F4ab/ac. It was mapped to SSC3q11-q14 by radiation hybrid mapping.

One-Step Solvothermal Synthesis of Tetranitro-Cobalt Phthalocyanine/Reduced Graphene Oxide Composite

Lijuan Zhang,Hejun Li,QIANGANG FU,Zhanwei Xu,Kezhi Li,Jianfeng Wei 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2015 NANO Vol.10 No.3

Tetranitro-cobalt phthalocyanine/reduced graphene oxide (TNCoPc/RGO) composite was prepared using ethylene glycol as reducing agent and precursor. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FT-IR) were used to characterize the composite. The electrochemical performance of the composite was examined by cyclic voltammetry and rotating disk electrode. The SEM observation and UV-Vis absorption spectrophotometer reveal that TNCoPc nanoparticles are closely contacted with RGO. The results show that the composite has a larger peak current and a higher current density than TNCoPc for oxygen reduction in an alkaline medium. This work offers a simple and environmental route for the synthesis of metal phthalocyanine (MPc)/RGO, which is adaptable to a wide range of applications in fuel cells.

Optimizing mechanical and thermal expansion properties of carbon/carbon composites by controlling textures

Wang Tiyuan,Zhang Shouyang,Ren Biyun,Li Kun,Li Wei,Li Hejun 한국물리학회 2020 Current Applied Physics Vol.20 No.10

The present study explored the effect of medium texture (MT) content on flexural properties and thermal expansion coefficients (CTES) of carbon/carbon (C/C) composites with multilayered pyrolytic carbon. The specimen with 39% MT exhibited maximum flexural strength of 221.55 MPa, increasing by 52% compared with pure high texture. While the flexural strength decreased when the MT content exceeded 39%. The excellent strength can be attributed to crack deflection between multilayered texture and the strong interface bonding between fibers and matrix. Moreover, the four specimens expressed a similar trend of CTES in the direction of XY and Z. In the direction of XY, the specimen with 39% MT had the lowest CTES from 800 ◦C to 2100 ◦C. Therefore, the C/C composites with 39% MT have the best mechanical and thermal expansion properties, which means that the properties of C/C composites can be optimized by controlling the texture.

Identification of HDAC9 as a viable therapeutic target for the treatment of gastric cancer

Kai Xiong,Hejun Zhang,Yang Du,Jie Tian,Shigang Ding 생화학분자생물학회 2019 Experimental and molecular medicine Vol.51 No.-

Histone deacetylase inhibitors (HDACis) are a new class of anticancer drugs confirmed to have good therapeutic effects against gastric cancer (GC) in preclinical experiments, but most HDACis are non-selective (pan-HDACis), with highly toxic side effects. Therefore, it is necessary to screen HDAC family members that play key roles in GC as therapeutic targets to reduce toxic side effects. In this study, we evaluated the targeting specificity of the HDACi suberoylanilide hydroxamic acid (SAHA) for GC via fluorescence molecular imaging (FMI). In vitro FMI results showed that SAHA had higher binding affinity for GC cells than for normal gastric cells. In vivo FMI of gastric tumor-bearing mice confirmed that SAHA can be enriched in GC tissues. However, there was also a high-concentration distribution in normal organs such as the stomach and lungs, suggesting potential side effects. In addition, we found that among the HDAC family members, HDAC9 was the most significantly upregulated in GC cells, and we verified this upregulation in GC tissues. Further experiments confirmed that knockdown of HDAC9 inhibits cell growth, reduces colony formation, and induces apoptosis and cell cycle arrest. These results suggest that HDAC9 has an oncogenic role in GC. Moreover, HDAC9 siRNA suppressed GC tumor growth and enhanced the antitumor efficacy of cisplatin in GC treatment by inhibiting the proliferation and inducing the apoptosis of GC cells in vitro and in vivo. Our findings suggest that the development of HDAC9-selective HDACis is a potential approach to improve the efficacy of chemotherapy and reduce systemic toxicity.

Analysis of Emergency Demand Response Levels of Central Air-Conditioning

Xianjun Qi,Zongshuo Ji,Hongbin Wu,Jingjing Zhang,Hejun Yang 대한전기학회 2020 Journal of Electrical Engineering & Technology Vol.15 No.6

Central air-conditioning (CAC) is a fl exible load which can be dispatched during an emergency demand response (EDR) program. However, consumers’ trade-off between thermal comfort levels (TCLs) and profi ts will aff ect the potential of CAC. Therefore, this paper proposes a method to evaluate CAC’S response levels. An EDR optimization model simulating consumers’ trade-off between TCLs and profi ts is established and it is solved by a particle swarm optimization (PSO) algorithm. Then the defi nition of EDR levels is presented to quantitatively analyze the capability of CAC providing the EDR. Furthermore, uncertainty of EDR levels caused by stochastic initial indoor temperature is analyzed through a Monte Carlo (MC) simulation. A case study shows the rationality of the presented method, and the eff ects of weight coeffi cients, compensation prices and penalty prices on EDR levels are also analyzed.

Association between the Polymorphism in FUT1 Gene and the Resistance to PWD and ED in Three Pig Breeds

Luo, Yanru,Qiu, Xiaotian,Li, Hejun,Zhang, Qin Asian Australasian Association of Animal Productio 2010 Animal Bioscience Vol.23 No.10

Post-weaning diarrhoea (PWD) and oedema disease (ED) caused by E. coli F18 always result in economic losses to pig producers, and no effective methods of controlling PWD and ED are presently available. FUT1 has been identified as a candidate gene controlling the expression of E. coli F18 receptor. This study examined the correlation between F18ab and F18ac adhesion phenotypes and the polymorphism at position M307 of the FUT1 gene in three pig breeds (231 Large White, 107 Landrace and 109 Songliao Black). The results showed: i) Both the susceptible genotypes (GG and GA) and the adhesion phenotypes (adhesive or weekly adhesive) were dominant in all three breeds with frequencies over 95%. ii) Three adhesion patterns of the two F18 variants F18ab and F18ac, i.e., ($ab^+$, $ac^+$), ($ab^+$, $ac^-$) and ($ab^-$, $ac^-$), were found in all three breeds, and there was no significant difference in the distribution of adhesion phenotypes of the two variants (separately or jointly) among the three breeds (p>0.05). iii) The FUT1 M307 genotypes were completely associated with the F18ab adhesion phenotypes and very strongly associated with the F18ac adhesion phenotypes. All individuals of genotype AA were non-adhesive to both F18ab and F18ac. All individuals of genotype GG or GA were adhesive to F18ab, whereas 11% of them were non-adhesive to F18ac. These results suggest that the polymorphism at FUT1 M307 can be used for marker-assisted selection of PWD and ED resistant pigs.