Three New Loci of Insertion Element IS1112 in Chinese Strains of Xanthomonas oryzae pv. Oryzae

Jiajian Xie,Xifeng Wang,Feiwu Li,Yufa Peng,Guanghe Zhou 한국미생물학회 2007 The journal of microbiology Vol.45 No.3

Insertion sequence IS1112 is a repetitive element with a relatively high number of copies in Xanthomonas oryzae pv. oryzae (Xoo), the causal agent of bacterial blight of rice (Oryza sativa L.). Three new loci of IS1112 were identified in seven Chinese strains of Xoo using a single oligonucleotide primer J3; 5'-GCTCAGGTCAGGTGGCCTGG-3’by insertion-sequence-based polymerase chain reaction (IS-PCR). Among the three new loci of IS1112, two were located in the open-reading frame region of genes fhuA and cirA, which encode TonB-dependent receptors, and the third in ISXo2, another type of insertion sequence in Xoo genome. Three variants of IS1112 were identified in those three loci based on their sequence similarities: two were identical to IS1112a and IS1112b, reported in strain PXO86 from the Philippines, while the third was a new member of IS1112, defined as IS1112d. Inserting IS1112 in gene fhuA caused three bases, GGT, to be duplicated at the target site, but inserting it in gene cirA did not cause any duplication in the target site. The diversity of IS1112 sequence and insertion loci in Xoo genome and their potential effects are discussed.

Three New Loci of Insertion Element IS1112 in Chinese Strains of Xanthomonas oryzae pv. oryzae

Xie, Jiajian,Wang, Xifeng,Li, Feiwu,Peng, Yufa,Zhou, Guanghe The Microbiological Society of Korea 2007 The journal of microbiology Vol.45 No.3

Insertion sequence IS1112 is a repetitive element with a relatively high number of copies in Xanthomonas oryzae pv. oryzae (Xoo), the causal agent of bacterial blight of rice (Oryza sativa L.). Three new loci of IS1112 were identified in seven Chinese strains of Xoo using a single oligonucleotide primer J3; 5'-GCTCA GGTCAGGTGGCCTGG-3' by insertion-sequence-based polymerase chain reaction (IS-PCR). Among the three new loci of IS1112, two were located in the open-reading frame region of genes fhuA and cirA, which encode TonB-dependent receptors, and the third in ISXo2, another type of insertion sequence in Xoo genome. Three variants of IS1112 were identified in those three loci based on their sequence similarities: two were identical to IS1112a and IS1112b, reported in strain PXO86 from the Philippines, while the third was a new member of IS1112, defined as IS1112d. Inserting IS1112 in gene fhuA caused three bases, GGT, to be duplicated at the target site, but inserting it in gene cirA did not cause any duplication in the target site. The diversity of IS1112 sequence and insertion loci in Xoo genome and their potential effects are discussed.

Influences of flow loss and inlet distortions from radial inlets on the performances of centrifugal compressor stages

Fenghui Han,Yijun Mao,Jiajian Tan 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.10

Radial inlets are typical upstream components of multistage centrifugal compressors. Unlike axial inlets, radial inlets generate additional flow loss and introduce flow distortions at impeller inlets. Such distortions negatively affect the aerodynamic performance of compressor stages. In this study, industrial centrifugal compressor stages with different radial inlets are investigated via numerical simulations. Two reference models were built, simulated, and compared with each original compressor stage to analyze the respective and coupling influences of flow loss and inlet distortions caused by radial inlets on the performances of the compressor stage and downstream components. Flow loss and inlet distortions are validated as the main factors through which radial inlets negatively affect compressor performance. Results indicate that flow loss inside radial inlets decreases the performance of the whole compressor stage but exerts minimal effect on downstream components. By contrast, inlet distortions induced by radial inlets negatively influence the performance of the whole compressor stage and exert significant effects on downstream components. Therefore, when optimizing radial inlets, the reduction of inlet distortions might be more effective than the reduction of flow loss. This research provides references and suggestions for the design and improvement of radial inlets.

Performance Improvement of Model Predictive Control Using Control Error Compensation for Power Electronic Converters Based on the Lyapunov Function

Guiping Du,Zhifei Liu,Fada Du,Jiajian Li 전력전자학회 2017 JOURNAL OF POWER ELECTRONICS Vol.17 No.4

This paper proposes a model predictive control based on the discrete Lyapunov function to improve the performance of power electronic converters. The proposed control technique, based on the finite control set model predictive control (FCS-MPC), defines a cost function for the control law which is determined under the Lyapunov stability theorem with a control error compensation. The steady state and dynamic performance of the proposed control strategy has been tested under a single phase AC/DC voltage source rectifier (S-VSR). Experimental results demonstrate that the proposed control strategy not only offers global stability and good robustness but also leads to a high quality sinusoidal current with a reasonably low total harmonic distortion (THD) and a fast dynamic response under linear loads.

Performance Improvement of Model Predictive Control Using Control Error Compensation for Power Electronic Converters Based on the Lyapunov Function

Du, Guiping,Liu, Zhifei,Du, Fada,Li, Jiajian The Korean Institute of Power Electronics 2017 JOURNAL OF POWER ELECTRONICS Vol.17 No.4

This paper proposes a model predictive control based on the discrete Lyapunov function to improve the performance of power electronic converters. The proposed control technique, based on the finite control set model predictive control (FCS-MPC), defines a cost function for the control law which is determined under the Lyapunov stability theorem with a control error compensation. The steady state and dynamic performance of the proposed control strategy has been tested under a single phase AC/DC voltage source rectifier (S-VSR). Experimental results demonstrate that the proposed control strategy not only offers global stability and good robustness but also leads to a high quality sinusoidal current with a reasonably low total harmonic distortion (THD) and a fast dynamic response under linear loads.

Large-scale flow measurements and analysis for radial inlets of industrial centrifugal compressors based on multi-hole probe system

Fenghui Han,Zhe Wang,Yijun Mao,Yiyun Zhang,Jiajian Tan 한국정밀공학회 2019 International Journal of Precision Engineering and Vol.20 No.1

Multi-hole probe (MHP), as a classical measuring instrument, continues to play an important role in the pressure and velocity measurements for industrial applications by virtue of its robust and reliable performance as well as the simple structure and low cost. But the flow directionality limitations and the low efficiency of traditional operations become obstacles to the large-scale measurements of MHPs. In this paper, an improved operating method is adopted for conventional MHPs to extend their measuring range of incidence angles, and a corresponding auto-measuring system has been developed to realize automatic calibration and measurement of MHPs for industrial large-scale flow measurements. Measurement uncertainties of the system have been experimentally analyzed, verifying a good accuracy: errors of 0.36° in pitch angle, 0.40° in yaw angle and 0.83% in velocity magnitude (95% CI). Furthermore, this auto-measuring system has been applied in the large-scale measurements on different radial inlets for industrial centrifugal compressors, which provide valuable flow information that was not previously available for industrial productions and assist with the improvement study. Analysis and applications in this paper prove that the developed system not only reduces the flow directionality limitations of conventional MHPs, but also significantly improves the experimental efficiency and the control-precision of the probe, achieves a good repeatability and ensures the reliability of the experimental data, which satisfies the requirements of large-scale measurements in industrial applications. Meanwhile, the portability of the system makes it more convenient and flexible to be applied in various industrial productions.

Numerical investigation of cavitation-vortex interaction in a mixed-flow waterjet pump

Renfang Huang,Bin Ji,Xianwu Luo,Zhihong Zhai,Jiajian Zhou 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.9

Turbulent cavitating flows in a mixed-flow waterjet pump were numerically investigated using the k-w SST turbulence model and themass transfer cavitation model based on the Rayleigh-Plesset equation to provide a comprehensive understanding of the cavitation-vortexinteraction mechanism. The predicted hydraulic performance, as well as the cavitation performance, exhibits a reasonable agreement withthe experimental results. The vorticity distributions under three operation conditions were illustrated together. Based on the illustration,cavitation development enhances vorticity production and flow unsteadiness in a mixed-flow waterjet pump. Vortices are basically locatedat the cavity interface, particularly at the downstream interface, during cavitation. Further analyses using the relative vorticity transportequation in cavitating turbulent flows indicate that vortex dilation and baroclinic torque exhibit a steep jump as cavitation occurs. Inaddition, vortex stretching contributes mainly to large-scale vortex generation.

Effect of Saccharomyces cerevisiae boulardii on sows’ farrowing duration and reproductive performance, and weanling piglets’ performance and IgG concentration

( Haiqing Sun ),( Fernando Bravo De Laguna ),( Shuai Wang ),( Fengju Liu ),( Liang Shi ),( Haidi Jiang ),( Xiaoxia Hu ),( Peng Qin ),( Jiajian Tan ) 한국축산학회 2022 한국축산학회지 Vol.64 No.1

We studied the effects of Saccharomyces cerevisiae boulardii CNCM I-1079 (LSB) supplemented to lactating sows on reproductive traits and farrowing duration and to piglets from day 7 of life on post-weaning performance and IgG concentration. Ninety-six Landrace × Yorkshire sows started the trial 5 days before the expected farrowing date. Sows were distributed into 2 groups according to parity number and backfat thickness: control (CON: regular lactation diet) and LSB (CON + LSB at 2 × 10⁹ colony forming units [CFU]/kg of feed). Seven days after birth, litters were randomly selected from each group and supplemented creep feed with or without LSB at 2 × 10⁹ CFU/kg. At weaning, piglets from CON sows were shifted to a commercial farm and allocated to 14 pens in groups of 25 piglets/pen according to the creep feed supplemented during lactation. Piglets followed a 3-phase feeding program: creep, pre-starter and starter, with or without LSB at 2 × 10⁹ CFU/kg LSB in creep and pre-starter, and 1 × 10⁹ CFU/kg LSB in starter. The piglets were vaccinated against classical swine fever on days 41 and 72 of life. One day before each vaccination and at the end of the trial, blood samples were collected from 15 randomly selected piglets per treatment and assessed for total IgG. Supplemented sows with non-supplemented litters displayed the lowest backfat thickness loss during lactation (p < 0.05). The LSB supplementation shortened farrowing duration (p < 0.05) and increased feed intake (p < 0.05) during the first week of lactation. The LSB-fed piglets were heavier at the end of creep (p < 0.05), pre-starter (p < 0.05), and the trial (p < 0.05); grew faster during creep (p < 0.05), starter (p < 0.05), and overall (p < 0.05); and displayed an improved feed conversion ratio during creep (p < 0.05). Total IgG content was higher at days 40 (p < 0.05) and 71 (p < 0.05) in LSB-fed piglets. We conclude that supplementing sows with Saccharomyces cerevisiae boulardii CNCM I-1079 from late gestation until weaning shortens farrowing duration, increases feed intake, and minimizes backfat losses during lactation. When supplemented to piglet diet, post-weaning performance is improved. This improvement observed could be linked to a better immune status, as suggested by the higher IgG.