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.

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.

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.

PREPARATION AND ELECTROCHEMICAL CAPACITIVE BEHAVIOR OF GRAPHENE BY MICROWAVE ASSISTED THERMAL REDUCTION OF GRAPHITE OXIDE IN HYDRAZINE HYDRATE

ZHEN SUN,Hejun Li,Kezhi Li,QIANGANG FU 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2014 NANO Vol.9 No.6

Graphene platelets with a large scale have been synthesized by reduction of graphene oxide (GO)in aqueous solution of hydrazine hydrate under microwave irradiation (MWI). Microstructure ofthe graphene was characterized by X-ray di®raction (XRD), Raman spectroscopy, atomic forcemicroscopy (AFM) and transmission electron microscopy (TEM) together with the selected areaelectron di®raction (SAED). The electrochemical properties were evaluated by the analysis ofcyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in 1 M Na 2 SO 4aqueous solution. The results show that the as-prepared materials consist of crumpled, few-layer( ? 3 nm) thick and electronically conductive graphitic sheets. The supercapacitors fabricatedusing this material possess a low equivalent series resistance (ESR) value ? 1.6 ? and a highspeci¯c capacitance of 285 F ? g ? 1 . In addition, the graphene reduced under a diverse duration ofMWI displays a di®erent interlayer spacing, extent of reduction, level of graphitization andspeci¯c capacitances. The duration of MWI and the treatment methods strongly a®ect the mi-crostructure of graphene, and then dominate its electrochemical properties.

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.

Study on the interventional path planning method of bronchoscope catheter

Yudong Bao,Xu LI,Wen Wei,Hejun Liu,Shengqian Qu 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.5

This paper presents a scientific approach to catheter intervention path planning. Firstly, it gives a three-dimensional reconstruction of bronchi using Mimics software based on CT image data. It also measures and analyzes geometric morphological data of the 3D model, which includes diameter, cross-sectional area, node spacing, and curvature at different locations. Secondly, starting from the bending structure of the catheter, Adams simulation experiments and with and without constraints of the serpentine bending structure were conducted. Comparison and analysis of the experimental results of the above three experiments to obtain the quantitative relationship of the bending angle. This study established a simple control device for interventional examination, verified the effect of the method on linear motion of the device, and provided some theoretical basis for future research to realize an automatic machine for human tracheal intervention.

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.

Dietary Supplementation with Acanthopanax senticosus Extract Modulates Cellular and Humoral Immunity in Weaned Piglets

Kong, Xiangfeng,Yin, Yulong,Wu, Guoyao,Liu, Hejun,Yin, Fugui,Li, Tiejun,Huang, Ruilin,Ruan, Zheng,Xiong, Hua,Deng, Zeyuan,Xie, Mingyong,Liao, Yiping,Kim, Sungwoo Asian Australasian Association of Animal Productio 2007 Animal Bioscience Vol.20 No.9

This study was conducted to test the hypothesis that dietary supplementation with an herbal extract of Acanthopanax senticosus (AS) enhances the immune response in weaned piglets. Sixty piglets weaned at 21 days of age were randomly assigned to 3 treatment groups representing the addition of 0 or 1 g/kg of the AS extract or 0.2 g/kg of colistin (an antibiotic) to maize- and soybean meal-based diets (n = 20 per group). On days 7, 14 and 28 after initiation of the addition, total and differential counts of leucocytes, proliferating activity of peripheral lymphocytes, serum levels of immunoglobulins (Ig) and cytokines and the spleen index were determined. The AS extract decreased (p<0.05) the number of neutrophils on days 7 and 28 in comparison with the control group and reduced (p<0.05) serum interleukin-$1{\beta}$ level on day 28 compared with the other 2 groups. Dietary supplementation with the AS extract increased (p<0.05) the lymphocyte/leukocyte ratio on day 28 compared with the control group and increased the proliferating activity of lymphocytes on days 14 and 28 compared with the other 2 groups. The AS extract increased (p<0.05) the serum content of IgG on day 7 and of IgG and IgM on day 28 compared with the other 2 groups, as well as increasing the serum content of tumor necrosis factor on day 7 and spleen index on days 7 and 28 compared with the control group. Collectively, these findings suggest that the AS extract as a dietary additive enhances the cellular and humoral immune responses of weaned piglets by modulating the production of immunocytes, cytokines and antibodies.

Sustainable production of acetaldehyde from lactic acid over the carbon catalysts

Cong-Ming Tang,Jiansheng Peng,Xin-Li Li,Zhanjie Zhai,Hejun Gao,Wei Bai,Ning Jiang,Yunwen Liao 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.1

The synthesis of acetaldehyde from lactic acid over the carbon material catalysts was investigated. The carbon materials were characterized by scanning electron microscopy for morphologic features, by X-ray diffraction for crystal phases, by Fourier transform infrared spectroscopy for functional group structures, by N2 sorption for specific surface area and by ammonia temperature-programed desorption for acidity, respectively. Among the tested carbon catalysts, mesoporous carbon displayed the most excellent catalytic performance. By acidity analysis, the medium acidity is a crucial factor for catalytic performance: more medium acidity favored the formation of acetaldehyde from lactic acid. To verify, we compared the catalytic performance of fresh activated carbon with that of the activated carbon treated by nitric acid. Similarly, the modified activated carbon also displayed better activity due to a drastic increase of medium acidity amount. However, in contrast to fresh carbon nanotube, the treated sample displayed worse activity due to decrease of medium acidity amount. The effect of reaction temperature and time on stream on the catalytic performance was also investigated. Under the optimal reaction conditions, 100% lactic acid conversion and 91.6% acetaldehyde selectivity were achieved over the mesoporous carbon catalyst.

Loading capacity evaluation of composite box girder with corrugated webs and steel tube slab

He, Jun,Liu, Yuqing,Xu, Xiaoqing,Li, Laibin Techno-Press 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.50 No.4

This paper presents a type of composite box girder with corrugated webs and concrete filled steel tube slab to overcome cracking on the web and reduce self-weight. Utilizing corrugated steel web improves the efficiency of prestressing introduced into the top and bottom slabs due to the accordion effect. In order to understand the loading capacity of such new composite structure, experimental and numerical analyses were conducted. A full-scale model was loaded monotonically to investigate the deflection, strain distribution, loading capacity and stiffness during the whole process. The experimental results show that test specimen has enough loading capacity and ductility. Based on experimental works, a finite element (FE) model was established. The load-displacement curves and stress distribution predicted by FE model agree well with that obtained from experiments, which demonstrates the accuracy of proposed FE model. Moreover, simplified theoretical analysis was conducted depending on the assumptions which were confirmed by the experimental and numerical results. The simplified analysis results are identical with the tested and numerical results, which indicate that simplified analytical model can be used to predict the loading capacity of such composite girder accurately. All the findings of present study may provide reference for the application of such structure in bridge construction.