Improved Method for Calculating Magnetic Field of Surface-Mounted Permanent Magnet Machines Accounting for Slots and Eccentric Magnet Pole

Zhou, Yu,Li, Huaishu,Wang, Wei,Cao, Qing,Zhou, Shi The Korean Institute of Electrical Engineers 2015 Journal of Electrical Engineering & Technology Vol.10 No.3

This paper presented an improved analytical method for calculating the open-circuit magnetic field in the surface-mounted permanent magnet machines accounting for slots and eccentric magnet pole. Magnetic field produced by radial and parallel permanent magnet is equivalent to that produced by surface current according to equivalent surface-current method of permanent magnet. The model is divided into two types of subdomains. The field solution of each subdomain is obtained by applying the interface and boundary conditions. The magnet field produced by equivalent surface current is superposed according to superposition principle of vector potential. The investigation shows harmonic contents of radial flux density can be reduced a lot by changing eccentric distance of eccentric magnet poles compared with conventional surface-mounted permanent-magnet machines with concentric magnet poles. The FE(finite element) results confirm the validity of the analytical results with the proposed model.

miR-101 Inhibiting Cell Proliferation, Migration and Invasion in Hepatocellular Carcinoma through Downregulating Girdin

Cao, Ke,Li, Jingjing,Zhao, Yong,Wang, Qi,Zeng, Qinghai,He, Siqi,Yu, Li,Zhou, Jianda,Cao, Peiguo Korean Society for Molecular and Cellular Biology 2016 Molecules and cells Vol.39 No.2

miR-101 is considered to play an important role in hepatocellular carcinoma (HCC), but the underlying molecular mechanism remains to be elucidated. Here, we aimed to confirm whether Girdin is a target gene of miR-101 and determine the tumor suppressor of miR-101 through Girdin pathway. In our previous studies, we firstly found Girdin protein was overexpressed in HCC tissues, and it closely correlated to tumor size, T stage, TNM stage and Edmondson-Steiner stage of HCC patients. After specific small interfering RNA of Girdin was transfected into HepG2 and Huh7.5.1 cells, the proliferation and invasion ability of tumor cells were significantly inhibited. In this study, we further explored the detailed molecular mechanism of Girdin in HCC. Interestingly, we found that miR-101 significantly low-expressed in HCC tissues compared with that in matched normal tissues while Girdin had a relative higher expression, and miR-101 was inversely correlated with Girdin expression. In addition, after miR-101 transfection, the proliferation, migration and invasion abilities of HepG2 cells were weakened. Furthermore, we confirmed that Girdin is a direct target gene of miR-101. Finally we confirmed Talen-mediated Girdin knockout markedly suppressed cell proliferation, migration and invasion in HCC while downregulation of miR-101 significantly restored the inhibitory effect. Our findings suggested that miR-101/Girdin axis could be a potential application of HCC treatment.

Comparative genomic analysis of Mycoplasma anatis strains

Zhou Qi,Mai Kaijie,Yang Dehong,Liu Junfa,Yan Zhuanqiang,Luo Cuifen,Tan Yangtong,Cao Sheng,Zhou Qingfeng,Chen Li,Chen Feng 한국유전학회 2021 Genes & Genomics Vol.43 No.11

Background The Gram-negative intracellular bacterium Mycoplasma anatis is a pathogen of respiratory infectious diseases in ducks and has caused signifcant economic losses in the poultry industry. Objective This study, as the frst report of the structure and function of the pan-genome of Mycoplasma anatis, may provide a valuable genetic basis for many aspects of future research on the pathogens of waterfowl. Methods We sequenced the whole genomes of 15 Mycoplasma anatis isolated from ducks in China. Draft genome sequencing was carried out and whole-genome sequencing was performed by the sequencers of the PacBio Sequel and an IonTorrent Personal Genome Machine (PGM). Then the common genic elements of protein-coding genes, tRNAs, and rRNAs of Mycoplasma anatis genomes were predicted by using the pipeline Prokka v1.13.7. To investigate homologous protein clusters across Mycoplasma anatis genomes, we adopted Roary v3.13.0 to cluster orthologous genes (OGs) based on the following criteria. Results We obtained one complete genome and 14 genome sketches. Microbial mobile genetic element analysis revealed the distribution of insertion sequences (IS30, IS3, and IS1634), prophage regions, and CRISPR arrays in the genome of Mycoplasma anatis. Comparative genomic analysis decoded the genetic components and functional classifcation of the pan-genome of Mycoplasma anatis that comprised 646 core genes, 231 dispensable genes and among them 110 was strainspecifc. Virulence-related gene profles of Mycoplasma anatis were systematically identifed, and the products of these genes included bacterial ABC transporter systems, iron transport proteins, toxins, and secretion systems. Conclusion A complete virulence-related gene profle of Mycoplasma anatis has been identifed, most of the genes are highly conserved in all strains. Sequencing results are relevant to the molecular mechanisms of drug resistance, adaptive evolution of pathogens, population structure, and vaccine development.

Improved Method for Calculating Armature-Reaction Field of Surface-Mounted Permanent Magnet Machines Accounting for Opening Slots

Zhou, Yu,Li, Huaishu,Wang, Qingyu,Xue, Zhiqiang,Cao, Qing,Zhou, Shi The Korean Institute of Electrical Engineers 2015 Journal of Electrical Engineering & Technology Vol.10 No.4

This paper presented an improved analytical method for calculating armature-reaction field in the surface-mounted permanent magnet machines accounting for opening slots. The analytical model is divided into two types of subdomains. The current of the armature is centralized in the center of the slots. The field solution of each subdomain is obtained by applying the interface and boundary conditions of the model. Two 30-pole/36-slot prototype machines with different slot-opening width are used for validation. The FE (finite element) results confirm the validity of the analytical results with the proposed model. The investigation shows that the wider the slot-opening width is, the smaller the peak value of radial and circumferential components of flux density, and the analytical armature-reaction field produced by centralized current in the slots is similar with the armature-reaction field produced by distributed current in the slots in the FE.

Numerical studies on non-shear and shear flows past a 5:1 rectangular cylinder

Zhou, Qiang,Cao, Shuyang,Zhou, Zhiyong Techno-Press 2013 Wind and Structures, An International Journal (WAS Vol.17 No.4

Large Eddy Simulations (LES) were carried out to investigate the aerodynamic characteristics of a rectangular cylinder with side ratio B/D=5 at Reynolds number Re=22,000 (based on cylinder thickness). Particular attention was devoted to the effects of velocity shear in the oncoming flow. Time-averaged and unsteady flow patterns around the cylinder were studied to enhance understanding of the effects of velocity shear. The simulation results showed that the Strouhal number has no significant variation with oncoming velocity shear, while the peak fluctuation frequency of the drag coefficient becomes identical to that of the lift coefficient with increase in velocity shear. The intermittently-reattached flow that features the aerodynamics of the 5:1 rectangular cylinder in non-shear flow becomes more stably reattached on the high-velocity side, and more stably separated on the low-velocity side. Both the mean and fluctuating drag coefficients increase slightly with increase in velocity shear. The mean and fluctuating lift and moment coefficients increase almost linearly with velocity shear. Lift force acts from the high-velocity side to the low-velocity side, which is similar to that of a circular cylinder but opposite to that of a square cylinder under the same oncoming shear flow.

Sampled-Data Modeling and Dynamic Behavior Analysis of Peak Current-Mode Controlled Flyback Converter with Ramp Compensation

Zhou, Shuhan,Zhou, Guohua,Zeng, Shaohuan,Xu, Shungang,Cao, Taiqiang The Korean Institute of Power Electronics 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.1

The flyback converter, which can be regarded as a nonlinear time-varying system, has complex dynamics and nonlinear behaviors. These phenomena can affect the stability of the converter. To simplify the modeling process and retain the information of the output capacitor branch, a special sampled-data model of a peak current-mode (PCM) controlled flyback converter is established in this paper. Based on this, its dynamic behaviors are analyzed, which provides guidance for designing the circuit parameters of the converter. With the critical stability boundary equation derived by a Jacobian matrix, the stable operation range with a varied output capacitor, proportional coefficient of error the amplifier, input voltage, reference voltage and slope of the compensation ramp of a PCM controlled flyback converter are investigated in detail. Research results show that the duty ratio should be less than 0.5 for a PCM controlled flyback converter without ramp compensation to operate in a stable state. The stability regions in the parameter space between the output capacitor and the proportional coefficient of the error amplifier are enlarged by increasing the input voltage or by decreasing the reference voltage. Furthermore, the ramp compensation also can extend to the stable region. Finally, time-domain simulations and experimental results are presented to verify the theoretical analysis results.

Sublethal effects of imidacloprid on the development, reproduction, and susceptibility of the white-backed planthopper, Sogatella furcifera (Hemiptera: Delphacidae)

Cao Zhou,Lei-lei Liu,Hong Yang,Zhao Wang,Gui-yun Long,Dao-chao Jin 한국응용곤충학회 2017 Journal of Asia-Pacific Entomology Vol.20 No.3

Sogatella furcifera (Horváth) (white-backed planthopper, WBPH) is one of the most important pests on rice in Asia. It seriously impacts rice production by sucking phloem from the rice plant and transmitting southern rice black-streaked dwarf virus (SRBSDV). In the current study, we examined the sublethal effects of imidacloprid on the development, reproduction, and susceptibility of S. furcifera in the laboratory using the rice stem dipping method. The results showed that exposure of third-instar S. furcifera nymphs to sublethal concentrations (LC10 and LC25) of imidacloprid inhibited the rate of nymphal development in the F0 and F1 generations, and there was a significant difference between the LC25 treated group and the control group. The fecundity (eggs per female) of the F1 generation showed significant declines of 22.05% and 38.56% following exposure to LC10 and LC25, respectively compared with the control group. Emergence rate, copulation rate, and hatchability were significantly lower in the LC25-treated group. The relative fitness of S. furcifera treated with LC10 and LC25 imidacloprid was 0.46 and 0.22, respectively. These results showed that exposure to imidacloprid impacted the next generation of S. furcifera, thus affecting the population growth of this species. After third-instar S. furcifera nymphs were exposed to sublethal concentrations of imidacloprid LC10 and LC25, S. furcifera showed reduced susceptibility to treatment with thiamethoxam and buprofezin. Although the susceptibility of S. furcifera to chlorpyrifos was decreased after the exposure of third-instar nymphs to imidacloprid LC25, S. furcifera populations that had been exposed to imidacloprid LC10 showed enhanced susceptibility to chlorpyrifos. These results provided a reference point for the application of insecticides to control S. furcifera.

Secretory Expression and Characterization of an Acidic Endo-Polygalacturonase from Aspergillus niger SC323 in Saccharomyces cerevisiae

( Huoxiang Zhou ),( Xi Li ),( Mingyue Guo ),( Qingrui Xu ),( Yu Cao ),( Dairong Qiao ),( Yi Cao ),( Hui Xu ) 한국미생물 · 생명공학회 2015 Journal of microbiology and biotechnology Vol.25 No.7

The endo-polygalacturonase gene (endo-pgaA) was cloned from DNA of Aspergillus niger SC323 using the cDNA synthesized by overlapping PCR, and successfully expressed in Saccharomyces cerevisiae EBY100 through fusing the α-factor signal peptide of yeast. The fulllength cDNA consists of 1,113 bp and encodes a protein of 370 amino acids with a calculated molecular mass of 38.8 kDa. After induction by galactose for 48 h, the activity of recombinant endo-PgaA in the culture supernatant can reach up to 1,448.48 U/mg. The recombinant protein was purified to homogeneity by ammonium sulfate precipitation and gel filtration column chromatography and subsequently characterized. The optimal pH and temperature of the purified recombinant enzyme were 5.0 and 50°C, respectively. The Michaelis-Menten constant (Km) and maximal velocity (Vmax) of the enzyme for pectin were 88.54 μmol/ml and 175.44 μmol/mg/min, respectively. The enzyme activity was enhanced by Ca2+, Cu2+, and Na+, and strongly inhibited by Pb2+ and Mn2+. The pectin hydrolysates were mainly galacturonic acid and other oligo-galacturonates. Therefore, these characteristics suggest that the recombinant endo-PgaA may be of potential use in the food and feed industries.

Sampled-Data Modeling and Dynamic Behavior Analysis of Peak Current-Mode Controlled Flyback Converter with Ramp Compensation

Shuhan Zhou,Guohua Zhou,Shaohuan Zeng,Shungang Xu,Taiqiang Cao 전력전자학회 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.1

The flyback converter, which can be regarded as a nonlinear time-varying system, has complex dynamics and nonlinearbehaviors. These phenomena can affect the stability of the converter. To simplify the modeling process and retain theinformation of the output capacitor branch, a special sampled-data model of a peak current-mode (PCM) controlled flybackconverter is established in this paper. Based on this, its dynamic behaviors are analyzed, which provides guidance for designingthe circuit parameters of the converter. With the critical stability boundary equation derived by a Jacobian matrix, the stableoperation range with a varied output capacitor, proportional coefficient of error the amplifier, input voltage, reference voltageand slope of the compensation ramp of a PCM controlled flyback converter are investigated in detail. Research results show thatthe duty ratio should be less than 0.5 for a PCM controlled flyback converter without ramp compensation to operate in a stablestate. The stability regions in the parameter space between the output capacitor and the proportional coefficient of the erroramplifier are enlarged by increasing the input voltage or by decreasing the reference voltage. Furthermore, the rampcompensation also can extend to the stable region. Finally, time-domain simulations and experimental results are presented toverify the theoretical analysis results.

Role of folP1 and folP2 Genes in the Action of Sulfamethoxazole and Trimethoprim Against Mycobacteria

( Tian Zhou Liu ),( Bang Xing Wang ),( Jin Tao Guo ),( Yang Zhou ),( Mugweru Julius ),( Moses Njire ),( Yuan Yuan Cao ),( Tian Wu ),( Zhi Yong Liu ),( Chang Wei Wang ),( Yong Xu ),( Tian Yu Zhang ) 한국미생물 · 생명공학회 2015 Journal of microbiology and biotechnology Vol.25 No.9

The combination of trimethoprim (TMP) and sulfamethoxazole (SMX) has been shown to be active against Mycobacterium tuberculosis (Mtb) in clinical tuberculosis (TB) treatment. However, the mechanism of action of TMP-SMX against Mtb is still unknown. To unravel this, we have studied the effect of TMP and SMX by deleting the folP2 gene in Mycobacterium smegmatis (Msm), and overexpressing the Mtb and Msm folP1/2 genes in Msm. Knocking out of the folP2 gene in Msm reduced the minimum inhibitory concentration of SMX 8-fold compared with wild type. Overexpression of the folP1 genes from Mtb and Msm increased the MICs by 4- and 2-fold in Msm for SMX and TMP, respectively. We show a strong correlation between the expression of folP1 and folP2 genes and TMP-SMX resistance in mycobacteria. This suggests that a combination of FolP2 inhibitor and SMX could be used for TB treatment with a better outcome.