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.

Research on Transformer Fault Diagnosis based on Multi-source Information Fusion

Xiaohui Wang,Kehe Wu,Yang Xu 보안공학연구지원센터 2014 International Journal of Control and Automation Vol.7 No.2

Improved Vibration Suppression Modeling for Reinforcement Clamping by Eco-friendly Magnetorheological Fluid During Milling of Annular Thin-Walled Workpiece

Xiaohui Jiang,Kun Wu,Yong Zhang,Shirong He 한국정밀공학회 2022 International Journal of Precision Engineering and Vol.9 No.6

Milling vibration will greatly affect the milling accuracy and surface quality of thin-walled workpiece. Considering that the characteristics of instant curing high-efficiently under the action of magnetic field and can be recycled without wasted of magnetorheological fluid (MRF), a MRF composite clamping to suppress milling vibration is proposed in this paper. Based on the fluid–solid coupling dynamics theory, the dynamics modal of the MRF clamping is established. On this basis, considering the influences of the filling volume of MRF to processing vibration, the suppression effect of MRF on milling vibration is analyzed in time domain and frequency domain, respectively. A series of simulations and experiments are carried out on typical annular thin-walled workpiece, the result shows that the maximum increase of natural frequency of thin-walled workpiece is 53.1% while filling with MRF, and Ra, Rz, Rq decreased by 36.1%, 14.8% and 16.7%, respectively. The consequence verified the reliability and effectiveness of the proposed method in the whole milling process.

Two Simplified Methods for Galloping of Iced Transmission Lines

Xiaohui Liu,Guangyun Min,Mengqi Cai,Bo Yan,Chuan Wu 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.1

For the galloping of iced transmission lines, the influences of two simplified methods of dynamic tension on the galloping characteristics of transmission lines are investigated. Based on the variational principle for Hamiltonian, the partial differential equation of galloping of iced transmission lines is derived, then it is transformed into ordinary differential equation by Galerkin method. Two different simplified methods are used to convert the partial differential equation into ordinary differential equation. One is to average the dynamic tension over the span length, then Galerkin method is used. The other is that Galerkin method is used to convert the partial differential equation into ordinary differential equation directly. Firstly, the influences of two simplified methods on coefficients of ordinary differential galloping equation are studied. Second, the influences of the bending stiffness on the first-order frequency have been researched. In addition, the average method of two degrees of freedom (DOFs) is proposed and the galloping characteristics of iced transmission lines are studied by using multiscale method and average method, then the results are compared with that obtained by using numerical method. The parameters analysis shows that the two simplified methods of dynamic tension have significant influences on the coefficients of the two DOFs ordinary differential equation. By comparing the coefficients of galloping equation obtained by the two simplified methods of dynamic tension, it can find that with the increasing of tension and span length, the influences of bending stiffness on in-plane and out-of-plane natural frequency becomes smaller and smaller. The results of multiscale method and average method both show that the two simplified methods of dynamic tension have certain influences on the frequency, phase and amplitude of galloping of iced transmission lines. The conclusions obtained by this paper would promote the perfection of theoretical modeling about iced transmission lines, and could also give some references to practical engineering.

Separation and Characterization of Organic Chlorides in a Chinese Crude Oil

Xiaohui Li,Rui Ma,Liang Ding,Huiying Yuan,Bencheng Wu,Jianhua Zhu 대한화학회 2018 Bulletin of the Korean Chemical Society Vol.39 No.4

A crude oil from Shengli oilfield of China was extracted with N,N‐dimethylformamide (DMF) for separation and enrichment of organic chlorides. The resulting extract with relatively higher chlorine concentration was analyzed with gas chromatography–mass spectrometry (GC/MS). Among the identified heteroatom compounds in the extract sample, nitrogen‐containing compounds were most abundant in the extract sample, followed by chlorine‐, sulfur‐, and oxygen‐containing compounds, respectively. Four organochlorines with an aromatic core structure, i.e., 5‐chloro‐2‐methylaniline, 2‐chloro‐6‐methylaniline, 4‐chloro‐2‐nitrotoluene, and 1‐(5‐chloro‐2‐hydroxyphenyl)ethanone, were identified from crude oil extract. The dominant abundant organic chloride is 5‐chloro‐2‐methylaniline with relative content of 65.1% in the total of identified organic chlorides, followed by 1‐(5‐chloro‐2‐hydroxyphenyl)ethanone of 16.3%, 2‐chloro‐6‐methylaniline of 14.5%, and 4‐chloro‐2‐nitrotoluene of 4.1%, respectively.

Efficient biosorption of Pb(II) from aqueous solutions by a PAH-degrading strain Herbaspirillum chlorophenolicum FA1

Xiaohui Li,Hongxia Xu,Bin Gao,Xiaoqing Shi,Yuanyuan Sun,Jichun Wu 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.57 No.-

For the first time, biosorption of lead(II) using a PAHs-degrading bacterium, Herbaspirillum chlorophenolicum FA1, was investigated as a function of initial lead concentration, biomass dosage, pH, and temperature in batch conditions. Results showed that FA1 was highly resistant to lead and grew well even at lead concentration of 200 mg L−1. The kinetic and isotherm data were well described by commonly used models, such as the pseudo-second-order and Langmuir models. Adsorption thermodynamics was spontaneous and endothermic, and FA1 exhibited a high sorption capacity of 151.52 mg g−1. SEM-EDS and FTIR analysis was conducted to further explore the interaction mechanisms.

Analysis of the DNA Methylation of Maize (Zea mays L.) in Response to Cold Stress Based on Methylation-sensitive Amplified Polymorphisms

Xiaohui Shan,Xiaoyu Wang,Guang Yang,Ying-Wu Lan,Shengzhong Su,Shipeng Li,Hongkui Liu,Yaping Yuan 한국식물학회 2013 Journal of Plant Biology Vol.56 No.1

DNA methylation plays a vital role in tuning geneexpression in response to environmental stimuli. Here,methylation-sensitive amplified polymorphisms (MSAP)were used to assess the effect of cold stress on the extent andpatterns of DNA methylation in maize seedlings. Overall,cold-induced genome-wide DNA methylation polymorphismsaccounted for 32.6 to 34.8% of the total bands at the differenttreatment time-points. It was demonstrated that the extentand pattern of DNA methylation was induced by cold stressthrough the cold treatment process and that thedemethylation of fully methylated fragments was the maincontributor of the DNA methylation alterations. The sequencesof 28 differentially amplified fragments relevant to stresswere successfully obtained. Under the cold stress, demethylationwas detected in most fragments. BLAST results indicate thatthe homologues of these fragments are involved in manyprocesses, including hormone regulation, cold response,photosynthesis, and transposon activation. The expressionanalysis demonstrated an increase in the transcription of fivedemethylated genes. Despite the fact that DNA methylationchanges and cold acclimation are not directly associated, ourresults may indicate that the specific demethylation of genesis an active and rapid epigenetic response to cold in maizeduring the seedling stage, further elucidating the mechanismof maize adaptation to cold stress.

Research on Panoramic Image Registration Approach based on Spherical Model

Xiaohui Wang,Kehe Wu,Shengzhuang Wang 보안공학연구지원센터(IJSIP) 2013 International Journal of Signal Processing, Image Vol.6 No.6

Characterization of Basic Nitrogen-Containing Compounds in the Products of Lube Base Oil Processing by Electrospray Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

Xiaohui Li,Jianhua Zhu,Bencheng Wu 대한화학회 2014 Bulletin of the Korean Chemical Society Vol.35 No.1

The distribution of basic nitrogen-containing compounds in three vacuum gas oils (VGOs) with different boiling ranges and their dewaxed oils from the lube base oil refining unit of a refinery were characterized by positive-ion electrospray ionization (ESI) Fourier transform-ion cyclotron resonance mass spectrometry (FT- ICR MS). It turned out that the composition of basic nitrogen compounds in the samples varied significantly in DBE and carbon number, and the dominant basic N-containing compounds in these oil samples were N 1 class species. N 1 O 1 , N 1 O 2 , and N 2 class species with much lower relative abundance were also identified. The composition of basic nitrogen compounds in VGOs and dewaxed VGOs were correlated with increased boiling point and varied in DBE and carbon numbers. The comparison of the analytical results between VGOs and dewaxed VGOs indicated that more basic N-containing compounds in VGO with low carbon number and small molecular weight tend to be removed by solvent refining in lube base oil processing.

Vector form intrinsic finite-element analysis of static and dynamic behavior of deep-sea flexible pipe

Wu, Han,Zeng, Xiaohui,Xiao, Jianyu,Yu, Yang,Dai, Xin,Yu, Jianxing The Society of Naval Architects of Korea 2020 International Journal of Naval Architecture and Oc Vol.12 No.1

The aim of this study was to develop a new efficient strategy that uses the Vector form Intrinsic Finite-element (VFIFE) method to conduct the static and dynamic analyses of marine pipes. Nonlinear problems, such as large displacement, small strain, and contact and collision, can be analyzed using a unified calculation process in the VFIFE method according to the fundamental theories of point value description, path element, and reverse motion. This method enables analysis without the need to integrate the stiffness matrix of the structure, because only motion equations of particles established according to Newton's second law are required. These characteristics of the VFIFE facilitate the modeling and computation efficiencies in analyzing the nonlinear dynamic problem of flexible pipe with large deflections. In this study, a three-dimensional (3-D) dynamical model based on 3-D beam element was established according to the VFIFE method. The deep-sea flexible pipe was described by a set of spatial mass particles linked by 3-D beam element. The motion and configuration of the pipe are determined by these spatial particles. Based on this model, a simulation procedure to predict the 3-D dynamical behavior of flexible pipe was developed and verified. It was found that the spatial configuration and static internal force of the mining pipe can be obtained by calculating the stationary state of pipe motion. Using this simulation procedure, an analysis was conducted on the static and dynamic behaviors of the flexible mining pipe based on a 1000-m sea trial system. The results of the analysis proved that the VFIFE method can be efficiently applied to the static and dynamic analyses of marine pipes.