Real-time PCR Targeting OmpA Gene for Detection of Cronobacter spp. in Powdered Infant Formula

Xiaohui Dong,Qingping Wu,Kui Wu,Jumei Zhang 한국식품과학회 2013 Food Science and Biotechnology Vol.22 No.2

Cronobacter spp. (formerly Enterobacter sakazakii), a pathogen commonly found in powdered infant formula (PIF), is a rare cause of invasive infection with a high mortality rate in neonates. In the present study, a realtime PCR assay was conducted to identify the pathogens in PIF using a TaqMan probe targeting the outer membrane protein A gene (ompA) of Cronobacter spp. The specificity of the PCR assay was tested against 25 strains of Cronobacter spp. and 38 non-Cronobacter bacterial species. The detection limits of this method are 1.0×102 copy/μL in standard plasmid, 1.1 CFU/100 g in PIF through 38 h of enrichment,and 2.8×102 CFU/mL in phosphate-buffered saline (pH 7.0). Based on the detection limits, real-time PCR is more sensitive than simplex and duplex PCR. These methods were successfully applied to actual samples, indicating that this real-time PCR assay can be used for the detection of Cronobacter spp. in PIF.

Back-stepping Fault-tolerant Control for Morphing Aircraft Based on Fixed-time Observer

Xiaohui Liang,Qing Wang,Bin Xu,Chaoyang Dong 제어·로봇·시스템학회 2021 International Journal of Control, Automation, and Vol.19 No.12

In this paper, the problem of the back-stepping fault-tolerant control (FTC) based on fixed-time observer is addressed for the morphing aircraft with model uncertainties, external disturbances, and actuator faults. First, thelongitudinal dynamics for the morphing process are presented, and the control-oriented models subject to undesired malfunctions are established. Second, the fixed-time observer is designed for offering estimations of compounddisturbances, including system uncertainties, disturbance, and malfunction information. Especially, the observer errors could converge to zero by the proposed observer within a settling time, which is independent of the system’sinitial conditions. Then, a back-stepping FTC strategy based on the observations is proposed for the altitude and velocity subsystem, and the stability of the close loop system would be guaranteed by the proposed controller despite the actuator failures. Furthermore, to eliminate the effects of the “explosion of complexity” of the backstepping method, a modified dynamic surface is applied to compute derivatives of virtual laws. Finally, the numerical simulations verify the effectiveness of the proposed control approach.

Current Review on the Research Status of Cemented Carbide Brazing: Filler Materials and Mechanical Properties

Xiaohui Yin,Qunshuang Ma,Bing Cui,Lei Zhang,Xingyan Xue,Sujuan Zhong,Dong Xu 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.4

Cemented carbides have been widely applied in cutting tools and wear-resistant components due to their ultrahigh hardnessand good wear resistance. However, the disadvantages of limited impact toughness and high cost have restricted their furtherapplication. Consequently, cemented carbides are usually joining with ductile steels to combine the advantages of both. Among various materials joining technologies, brazing have been an effective method to achieve high quality dissimilarcemented carbide joints. In this paper, the research status of cemented carbide brazing is reviewed. The materials utilized asbrazing filler metal in cemented carbide brazing joints are summarized in detail. Researchers have done lots of works utilizingCu based and Ag based brazing filler metals which are the most commonly used interlayers in brazed joints of cementedcarbide and ductile steel. The effects of different filler metal on wettability, microstructure, phase constitution and mechanicalproperties of brazed cemented carbides joints are analysed. Besides, a series of newly developed brazing filler materialsuch as nickel-based high temperature brazing filler metal, amorphous brazing filler metal and high entropy alloy brazingfiller materials are also involved. These newly developed brazing filler metals have shown great potential in fabricating highquality joints. Finally, the current issues of cemented carbide brazing are reviewed and the develop trend is predicted.

Refining Characteristics of Hardwood Pulp Using Straight- and Curved-bar Plates: A Time Series Study

Huan Liu,Jixian Dong,Xiaojun Jiang,Chong Luo,Xiaohui Tian,Ruifang Yang,Litao Zhang,Bo Wang,Yan Yan 한국펄프·종이공학회 2019 펄프.종이기술 Vol.51 No.5

There are obvious differences in the refining characteristics of plates with straight bars compared to curved bar plates having the same bar parameters during refining. The objective of this research is to explore the difference in the refining characteristics of the straight bar and curved bar plates on experimental and theoretical studies. The bar angle of the curved bar plate is defined, and the two plates are used in the refining of bleached sulphate eucalyptus pulp (BSEP). Samples at different refining times were collected, and the properties of the fibers, pulp, and paper were detected and analyzed. It was found that the curved bar and straight bar plates have a similar influence on the pulp SR freeness. However, the curved bar plate effectively retained the fiber length, which means that its fiber cutting effect is weaker than that of the straight bar plate. Meanwhile, the fiber external fibrillation of the samples refined by the curved bar plate was better than that of the samples refined by the straight bar, which showed a higher tensile and tear index of the formed paper. Through the theoretical analysis of refining intensity via characterization of the parameter bar edge length (BEL), the specific edge load (SEL) of the curved bar plate was lower, and the refining characteristics predicted by the refining intensity were similar to the results from the experiments conducted in this paper.

American ginseng significantly reduced the progression of high-fatdiet-enhanced colon carcinogenesis in ApcMin/þmice

Chunhao Yu,Xiao-Dong Wen,Zhiyu Zhang,Chun-Feng Zhang,Xiaohui Wu,Xin He,Yang Liao,Ningning Wu,Chong-Zhi Wang,Wei Du,Tong-Chuan He,Chun-Su Yuan 고려인삼학회 2015 Journal of Ginseng Research Vol.39 No.3

Background: Colorectal cancer (CRC) is a leading cause of death worldwide. Chronic gut inflammation is recognized as a risk factor for tumor development, including CRC. American ginseng is a very commonly used ginseng species in the West. Methods: A genetically engineered ApcMin/þ mouse model was used in this study. We analyzed the saponin composition of American ginseng used in this project, and evaluated its effects on the progression of high-fat-diet-enhanced CRC carcinogenesis. Results: After oral ginseng administration (10e20 mg/kg/d for up to 32 wk), experimental data showed that, compared with the untreated mice, ginseng very significantly reduced tumor initiation and progression in both the small intestine (including the proximal end, middle end, and distal end) and the colon (all p < 0.01). This tumor number reduction was more obvious in those mice treated with a low dose of ginseng. The tumor multiplicity data were supported by body weight changes and gut tissue histology examinations. In addition, quantitative real-time polymerase chain reaction analysis showed that compared with the untreated group, ginseng very significantly reduced the gene expression of inflammatory cytokines, including interleukin-1a (IL-1a), IL-1b, IL-6, tumor necrosis factor-a, granulocyte-colony stimulating factor, and granulocyte-macrophage colony-stimulating factor in both the small intestine and the colon (all p < 0.01). Conclusion: Further studies are needed to link our observed effects to the actions of the gut microbiome in converting the parent ginsenosides to bioactive ginseng metabolites. Our data suggest that American ginseng may have potential value in CRC chemoprevention.

Study on Fiber Cutting Performance of Isometric Straight Bar Plate with Different Bar Angle

Huan Liu,Jixian Dong,Xiya Guo,Chong Luo,Xiaohui Tian,Xiaojun Jiang,Sha Wang,Ruifan Yang,Chuanwu Duan,Bo Wang,Kai Qi 한국펄프·종이공학회 2019 펄프.종이기술 Vol.51 No.5

The refining plate is a direct-acting component of refiners in pulping, and the bar profile of it have a major impact on fiber cutting, which affects the paper forming and strength of the formed paper. In this paper, the fiber average length, the fiber length distribution, the original fiber cutting rate and adjacent fiber cutting rate of samples collected in different refining time are used to analyze the fiber cutting mechanism of the isometric straight bar refining plates with different bar angles. The results show that the fiber cutting performance of plates gradually decreases and the limit fiber cutting length of the plate increases with the increase of the bar angle which is opposite to the conclusion predicted by specific edge load (SEL). However, the fiber cutting action of plates is gradually weakened until the average fiber length is reduced to the limit cutting length of plates. Meanwhile, the cutting mechanism of the straight bar plates with different bar angles is different. The larger bar angle of plate, the lower fiber cutting rate and the adjacent cutting rate of which is basically kept constant during refining, while the adjacent cutting rate of smaller bar angle plate on fibers gradually decreases with refining and finally remains constant. The study on the cutting performance of different bar angle plates has positive significance for the selection and design of refining plates for different pulping process.

American ginseng significantly reduced the progression of high-fat-diet-enhanced colon carcinogenesis in Apc^Min/+ mice

Yu, Chunhao,Wen, Xiao-Dong,Zhang, Zhiyu,Zhang, Chun-Feng,Wu, Xiaohui,He, Xin,Liao, Yang,Wu, Ningning,Wang, Chong-Zhi,Du, Wei,He, Tong-Chuan,Yuan, Chun-Su The Korean Society of Ginseng 2015 Journal of Ginseng Research Vol.39 No.3

Background: Colorectal cancer (CRC) is a leading cause of death worldwide. Chronic gut inflammation is recognized as a risk factor for tumor development, including CRC. American ginseng is a very commonly used ginseng species in the West. Methods: A genetically engineered $Apc^{Min/+}$ mouse model was used in this study. We analyzed the saponin composition of American ginseng used in this project, and evaluated its effects on the progression of high-fat-diet-enhanced CRC carcinogenesis. Results: After oral ginseng administration (10-20 mg/kg/d for up to 32 wk), experimental data showed that, compared with the untreated mice, ginseng very significantly reduced tumor initiation and progression in both the small intestine (including the proximal end, middle end, and distal end) and the colon (all p < 0.01). This tumor number reduction was more obvious in those mice treated with a low dose of ginseng. The tumor multiplicity data were supported by body weight changes and gut tissue histology examinations. In addition, quantitative real-time polymerase chain reaction analysis showed that compared with the untreated group, ginseng very significantly reduced the gene expression of inflammatory cytokines, including interleukin-$1{\alpha}$ (IL-$1{\alpha}$), IL-$1{\beta}$, IL-6, tumor necrosis factor-${\alpha}$, granulocyte-colony stimulating factor, and granulocyte-macrophage colony-stimulating factor in both the small intestine and the colon (all p < 0.01). Conclusion: Further studies are needed to link our observed effects to the actions of the gut microbiome in converting the parent ginsenosides to bioactive ginseng metabolites. Our data suggest that American ginseng may have potential value in CRC chemoprevention.

One-Step CVD Synthesis of Few-Layer SnS2/MoS2 Vertical Heterostructures

Hongxiao Zhao,Yong Yan,Xiaohui Song,Aodi Dong,Jian Su,Huimin Jia 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.10

Constructing van der Waals (vdW) heterostructures with various-layered two-dimensional (2D) materials is attractive to design various materials and devices. For controllable fabrication of vdW heterostructures, it is very important to make the growth process clear. In this work, SnS2/MoS2 vertical heterostructures were synthesized by the one-step chemical vapor deposition (CVD) method. The bottom MoS2 triangle layers can be partially or completely covered by SnS2 layers. The interlayer charge separation was also observed in the heterostructures by photo-luminescence (PL) spectroscopy. The growth mechanism of SnS2/MoS2 vertical heterostructures was also discussed for the first time. MoS2 triangle layers form on the substrates at first and then grow a top layer of SnS2. This study will provide an important and practical method, as a guidance to prepare high-quality vertical heterostructures.

Two-dimensional porous polyphthalocyanine (PPc) as an efficient gas-separation membrane for ammonia synthesis

Zhaoran Wang,Huilong Dong,Xiaohui Yu,Yujin Ji,Tingjun Hou,Youyong Li 한국물리학회 2017 Current Applied Physics Vol.17 No.12

Porous monolayer materials have been proven potential for gas separation and purification, because of their natural pathways of controllable sizes and well-ordered distribution. In this work, a novel material, two-dimensional (2D) porous polyphthalocyanine (PPc) is investigated by density functional theory (DFT) simulations for separating NH3 from H2 and N2 during ammonia synthesis process. Based on the calculated diffusion barriers through transition state search, we demonstrate that 2D PPc is able to offer high selectivity (107) of (H2, N2)/NH3 at room temperature. Further molecular dynamics (MD) simulation also indicates that the 2D PPc can effectively separate NH3 from H2 and N2. Thus the 2D PPc is promising for the practical applications of synthetic ammonia process.

Wear Resistance of the La62Cu12Ni12Al14 Bulk Metallic Glass Under Dry Friction Conditions

Guo, Jing,Joo, Soo-Hyun,Pi, Dong-Hai,Zhang, Xiaohui,Zhang, Xiaorong,Abdelaal, Mohamed,Song, Yuepeng,Kim, Hyoung Seop Springer-Verlag 2017 Tribology letters Vol.65 No.2