Parallel Gene Loss and Acquisition Among Strains of Different Brucella Species and Biovars

Zhijun Zhong,Yufei Wang,Jie Xu,Yanfen Chen,Yuehua Ke,Xiaoyan Zhou,Xitong Yuan,Dongsheng Zhou,Yi Yang,Ruifu Yang,Guangneng Peng,Hai Jiang,Jing Yuan,Hongbin Song,Buyun Cui,Liuyu Huang,Zeliang Chen 한국미생물학회 2012 The journal of microbiology Vol.50 No.4

The genus Brucella is divided into six species; of these, B. melitensis and B. abortus are pathogenic to humans, and B. ovis and B. neotomae are nonpathogenic to humans. The definition of gene loss and acquisition is essential for understanding Brucella’s ecology, evolutionary history, and host relationships. A DNA microarray containing unique genes of B. melitensis Type strain 16MT and B. abortus 9-941 was constructed and used to determine the gene contents of the representative strains of Brucella. Phylogenetic relationships were inferred from sequences of housekeeping genes. Gene loss and acquisition of different Brucella species were inferred. A total of 214 genes were found to be differentially distributed,and 173 of them were clustered into 15 genomic islands (GIs). Evidence of horizontal gene transfer was observed for 10GIs. Phylogenetic analysis indicated that the 19 strains formed five clades, and some of the GIs had been lost or acquired independently among the different lineages. The derivation of Brucella lineages is concomitant with the parallel loss or acquisition of GIs, indicating a complex interaction between various Brucella species and hosts.

Bismuth stannate nanoparticles for enhancing fire safety of flexible polyvinyl chloride: Preparation, evaluation, and mechanism

Zhaodong Yuan,Xiaowei Zhao,Shuaiqiang Nie,Xiaohong Li,Zhijun Zhang,Zhiwei Li 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.122 No.-

To replace traditional toxic Sb2O3 flame retardants, Bi2Sn2O7 (BSO) nanoparticles were prepared by a coprecipitationmethod and used as flame retardants of flexible polyvinyl chloride (PVC) for the first time. Structural characterization revealed that as-prepared BSO nanoparticles had a cubic phase with an averagediameter of 20 nm. Under 3 wt% loading, the PVC/BSO composite gained a limiting oxygen index of29%, very close to 29.5% of PVC/Sb2O3. In particular, the PVC/BSO composites passed the UL-94V-0 rating,while PVC/Sb2O3 failed. The PVC/BSO composite also showed better heat and smoke suppression performancethan Sb2O3, with a 27.4% decrease in peak heat release rate and a 39.9% decrease in total smokeproduction, compared with the PVC matrix. The excellent performance is attributed to following two reasons:In the gas phase, similar to Sb, Bi can form BiCl3, which dilutes the combustion gas and captureshydroxyl radicals; In the condensed phase, Sn in BSO helps form more protective char residue with theleast pores and the highest degree graphitization. In addition, the tensile strength and elongation at breakof PVC/BSO were also slightly superior to those of PVC/Sb2O3. In conclusion, BSO nanoparticles will be apromising substitute for toxic Sb2O3 flame retardants.

Wind farm resonance characteristics analysis based on harmonic impedance measurement method

Yang, Yude,Yuan, Lili,Qin, Zhijun,Liu, Hui The Korean Institute of Power Electronics 2020 JOURNAL OF POWER ELECTRONICS Vol.20 No.4

Recently, subsynchronous oscillation (SSO) has been captured in direct-drive permanent magnetic synchronous generator (PMSG) based wind farms in many areas without series compensation in nearby power grids. However, there are fewer reports related to this new type of SSO. In addition, an analysis of the new SSO based on existing methods is computationally cumbersome, and the control effect of the converter was generally simplified in previous studies, which lead to serious errors. This paper proposes a method for analyzing the resonance characteristics of wind farms based on impedance measurement to simplify calculations and improve accuracy. The correctness and effectiveness of the proposed method are validated through the IEEE first benchmark model. A time-domain simulation model of a direct-drive PMSG is established and analyzed by harmonic impedance measurement. The results show that SSO exists when direct-drive PMSGs are connected to a weak AC system. The converter of the direct-drive PMSG exhibits a small negative value at the oscillation mode frequency. This means that the converter behaves like a capacitor with negative impedance. The capacitive impedance of the converter forms a resonant loop with the inductance of the AC grid and causes unstable SSO.

RGB-D Sensor-based Visual Target Detection and Tracking for an Intelligent Wheelchair Robot in Indoors Environments

Hanzhen Xiao,Zhijun Li,Chenguang Yang,Wang Yuan,Liyang Wang 제어·로봇·시스템학회 2015 International Journal of Control, Automation, and Vol.13 No.3

The ability to follow or move alongside a person is a necessary skill for an autonomous mobile agent that works with human users. To accomplish such tasks, we develop a new scheme of visual-target de-tection and tracking for a wheelchair robot equipped with Microsoft Kinect that captures RGB images along with per-pixel depth information (RGB-D camera). The speeded-up semi-supervised on-line boosting algorithm is employed to provide the robust description of feature for environments and the target person from RGB images. Based on the environmental Haar-like features, we utilize an ex-tended Kalman filter (EKF) based localization to estimate robot pose. Then obstacle avoidance navigation approach based on η3 spline trajectory planning and optimization are proposed for the wheelchair robot. Finally, the experimental results are provided to demonstrate the effectiveness and feasibility in real world environments.

Low beta superconducting cavity system design for HIAF iLinac

Mengxin Xu,Yuan He,Shengxue Zhang,Lubei Liu,Tiancai Jiang,Zehua Liang,Tong Liu,Yue Tao,Chunlong Li,Qitong Huang,Fengfeng Wang,Hao Guo,Feng Bai,Xianbo Xu,Shichun Huang,Xiaoli Li,Zhijun Wang,Shenghu Zha Korean Nuclear Society 2023 Nuclear Engineering and Technology Vol.55 No.7

A superconducting ion-Linac (iLinac), which is supposed to work as the injector in the High Intensity heavy-ion Accelerator Facility project, is under development at the Institute of Modern Physics (IMP), Chinese Academy of Sciences. The iLinac is a superconducting heavy ion linear accelerator approximately 100 meters long and contains 96 superconducting cavities in two types of 17 cyromodules. Two types of superconducting resonators (quarter-wave resonators with a frequency of 81.25 MHz and an optimal beta β = v/c = 0.07 called QWR007 and half-wave resonators with a frequency of 162.5 MHz and an optimal beta β = 0.15 called HWR015) have been investigated. The cavity design included extensive multi-parameter electromagnetic simulations and mechanical analysis, and its results are described in details. The fundamental power coupler and cavity dynamic tuner designs are also presented in this article. The prototypes are under manufacturing and expected to be ready in 2023.

Promoting Osseointegration of New Innocuous Ti–18Zr–13Mo Implant Through Constructing Hierarchically Structured Bioactive Coating

Bianyun Cai,Delin Yuan,Guangda Li,Kun Lei,Meng Han,Yizhou Huang,Zhijun Guo 대한금속·재료학회 2023 METALS AND MATERIALS International Vol.29 No.11

This study aimed to improve osteointegration performance of the new innocuous Ti–18Zr–13Mo implant through constructinghierarchically structured bioactive coating. A micro/nano-scaled fibrous network topography as well as bioactive componentsof calcium phosphate compounds were assigned to Ti–18Zr–13Mo alloy surface by a two stepped hydrothermal processfor making its physical structure and chemical composition more closer to natural bone tissue. Scanning electron microscopy,transmission electron microscope, energy dispersive spectrometer, X-ray diffraction, X-ray photoelectron spectroscopy,atomic force microscopy and contact angle measurement had been applied to characterize the surface coating. Furthermore,we in-depth explored the formation process and mechanism of the hybrid bionic coating using knowledge of energetic andcrystallography. Following the treatment, the coated Ti–18Zr–13Mo implant showed significant boosting of MC3T3-E1osteoblasts’ activity, adhesion and differentiation ability in vitro. The modification technology of the hierarchical bioactivecoating can provide a strong guarantee for practical orthopedic and dental applications of Ti–18Zr–13Mo implant. Besides,the promising results will further expand the research fertile ground of Ti-based alloy and other metal implant and prosthesis.

Data-Driven Support Vector Machine with Optimization Techniques for Structural Health Monitoring and Damage Detection

Guoqing Gui,Hong Pan,Zhibin Lin,Yonghua Li,Zhijun Yuan 대한토목학회 2017 KSCE JOURNAL OF CIVIL ENGINEERING Vol.21 No.2

Rapid detecting damages/defeats in the large-scale civil engineering structures, assessing their conditions and timely decision making are crucial to ensure their health and ultimately enhance the level of public safety. Advanced sensor network techniques recently allow collecting large amounts of data for structural health monitoring and damage detection, while how to effectively interpret these complex sensor data to technical information posts many challenges. This paper presents three optimization-algorithm based support vector machines for damage detection. The optimization algorithms, including grid-search, partial swarm optimization and genetic algorithm, are used to optimize the penalty parameters and Gaussian kernel function parameters. Two types of feature extraction methods in terms of time-series data are selected to capture effective damage characteristics. A benchmark experimental data with the 17 different scenarios in the literature were used for verifying the proposed data-driven methods. Numerical results revealed that all three optimized machine learning methods exhibited significantly improvement in sensitivity, accuracy and effectiveness over conventional methods. The genetic algorithm based SVM had a better prediction than other methods. Two different feature methods used in this study also demonstrated the appropriate features are crucial to improve the sensitivity in detecting damage and assessing structural health conditions. The findings of this study are expected to help engineers to process big data and effectively detect the damage/defects, and thus enable them to make timely decision for supporting civil infrastructure management practices.