RNAi suppression of nuclear receptor genes results in increased susceptibility to sulfoxaflor in brown planthopper, Nilaparvata lugens

Lu Xu,Chun-Qing Zhao,De-Jin Xu,Guang-Chun Xu,Xiao-Long Xu,Zhao-Jun Han,Ya-Nan Zhang,Zhong-Yan Gu 한국응용곤충학회 2017 Journal of Asia-Pacific Entomology Vol.20 No.2

Nuclear receptors (NRs), which belong to a superfamily of ligand-dependent transcription factors, play essential roles in gene regulation to affect numerous physiological pathways. Twenty NR genes were identified in Nilaparvata lugens by using genomic, transcriptomic and GenBank databases, and categorized into NR0-NR6 subfamilies according to standard nomenclature. Among them, three NR geneswere classed into NR0, four into NR1, eight into NR2, one into NR3, one into NR4, two into NR5, and one into NR6, respectively. A phylogenetic tree of NRs from N. lugens and other representative species was constructed, which provided evolutionary insight into genetic distance. In order to investigate the NRs,whichwere induced by sulfoxaflor, time- and tissue-specific expression profiles of NR genes in fourth-instar nymphs were determined following LD50 sulfoxaflor treatment (0.28 ng/insect) and compared with control samples. NlUSP, NlE78, NlTLL, NlHR51, NlHR83, NlPNR and NlFTZ-F1 were highly expressed following 12–48 h of sulfoxaflor treatment. NlHR39 and NlDSF transcripts were detected in the head and the thorax, respectively. High-level and constitutive expression of NlHR3, NlTLL, NlHR83, NlFTZF1 and NlHR4 were found in the abdomen. Feeding of dsRNAs reduced the expression of NlHR3, NlUSP, NlTLL, NlHR83, NlPNR, NlFTZ-F1 and NlHR4 (35.48–49.77%) and caused significant nymph mortality (69.21–81.45%). These NRs, considered as insecticide targets, may play important function in sulfoxaflor detoxification.

Control Strategy and Characteristic Analysis of Hybrid Active Power Filters with the Resonant Impedance Principle

Lu Fang,Xian-yong Xu,An Luo,Yan Li,Chun-ming Tu,Hou-hui Fang 전력전자학회 2012 JOURNAL OF POWER ELECTRONICS Vol.12 No.6

A new kind of resonant impedance type hybrid active filter (RITHAF) is proposed for dynamic harmonic current suppression and high capacity reactive compensation in medium and high voltage systems. This paper analyzed the different performance of the RITHAF when the active part of the RITHAF is controlled as a current source and as a voltage source, respectively. The harmonic suppression function is defined in this paper. The influences of the changes caused by the grid impedance and the detuning of the passive power filter on the compensating characteristics of the RITHAF are studied by analyzing the suppression function. Simulation and industrial application results show that the RITHAF has excellent performances in harmonic suppression and reactive compensation, which is suitable for medium and high voltage systems.

Lethal and sublethal effects of sulfoxaflor on the small brown planthopper Laodelphax striatellus

Lu Xu,Chun-Qing Zhao,Ya-Nan Zhang,Ying Liud,,Zhong-Yan Gu 한국응용곤충학회 2016 Journal of Asia-Pacific Entomology Vol.19 No.3

Laodelphax striatellus (Fallén), as an important pest of gramineous crops, has developed resistance to multiple classes of insecticides, impairing control efficiency. However, the application of insecticides is still the main controlmeasure for it.Herein, the lethal effects of seven insecticides aswell as sulfoxaflor,which has been introduced and registered for controlling L. striatellus in China, were investigated. The acute toxicity of these insecticides on the L. striatellus adultswas rankedas sulfoxaflor N abamectin N dinotefuran N emamectin benzoate N ethofenprox N imidacloprid N chlorantraniliprole N chlorpyrifos. The toxicity of sulfoxaflor against the adultswas highestwith LD50 at 1.07–1.09 ng/insect. In addition, the sublethal effects of lower lethal dose LD3 (0.06 ng/insect), low lethal dose LD10 (0.15 ng/insect) and moderate lethal dose LD30 (0.49 ng/insect) of sulfoxaflor for L. striatellus were assessed as well. Both LD10 and LD30 induced slower nymphal development period, shorter oviposition period and longer pre-oviposition period in L. striatellus. The LD30 also shortened the longevity of females. Hormesis on fecunditywas observed in L. striatellus exposed to LD3. Therefore, the net reproductive rate (R0) was increased by LD3. The intrinsic rate of increase (rm) was reduced by LD10 and LD30 while mean generation time(T) and doubling time (DT) were prolonged. The acute sulfoxaflor doses in its toxicological properties need to be considered when develop L. striatellus control strategy with sulfoxaflor. These results demonstrate that sulfoxaflor is a valid candidate for L. striatellus management.

Multiple down-regulated cytochrome P450 monooxygenase genes contributed to synergistic interaction between chlorpyrifos and imidacloprid against Nilaparvata lugens

Lu Xue,Guanghua Luo,Yang Sun,Shuijin Huang,De-Jin Xu,Guang-Chun Xu,Zhao-Jun Han,Zhong-Yan Gu,Ya-Nan Zhang 한국응용곤충학회 2020 Journal of Asia-Pacific Entomology Vol.23 No.1

Insecticide mixtures are an effective strategy in pest resistance management. The synergistic chlorpyrifos and imidacloprid mixture could significantly increase toxicity against rice pest, Nilaparvata lugens, despite their high levels of resistance. However, synergism mechanisms to explain this phenomenon remain unknown. Chlorpyrifos and imidacloprid at a 1:0.5 ratio showed significant synergism on N. lugens with a combination index value of 0.18 after topical exposure. We constructed a genetic database of the genes expressed in individual and synergistic chlorpyrifos and imidacloprid treatments of N. lugens using Illumina Hiseq™ X Ten, and 17 co-downregulated genes putatively involved in synergism were detected by comparative transcriptome analyses. Expression patterns of the 17 candidate synergistic genes matched with transcriptome sequencing data by quantitative real-time PCR analyses. Feeding of dsRNAs further reduced the expression levels of 10 of these candidate synergistic genes (from 1.68 to 4.13-fold). Nymphs fed with only dsRNAs of CYP4DE1, CYP6AY1v2, CYP353D1, and CYP439A1 experienced more high mortality rates (81.45–90.34%) to improve synergism between chlorpyrifos and imidacloprid. Multiple reductive expressed P450 genes were potentially associated with synergism of a mixture of chlorpyrifos and imidacloprid, as confirmed by comparative transcriptome analyses and RNAi assays. Our findings suggested that synergistic interactions between chlorpyrifos and imidacloprid might be controlled by P450s.

Mechanical Performance of 3D-Printing Plastic Honeycomb Sandwich Structure

Chun Lu,Mingxue Qi,Shafiul Islam,Ping Chen,Shuangsheng Gao,Yanrong Xu,Xiangdong Yang 한국정밀공학회 2018 International Journal of Precision Engineering and Vol.5 No.1

In this study, Bi-Grid, Tri-Grid, Quadri-Grid and Kagome-Grid honeycombs were designed and fabricated using 3D printing technology Sandwich composites were prepared by gluing the cores and composite face sheets together. Mechanical performance of the sandwich structures were characterized using finite element analysis and three-point bending test. Results indicate that when suffering from bending loads, the stress concentrations are located at the loading zone on upper face sheets (distributed in both sides of the indenter) and supporting zone on bottom face sheets, and the stress concentration zones of the honeycomb cores are located in the area that between indenter and supports. The failure mechanism of the Bi-Grid sandwich structure is interfacial de-bonding between composite face sheet and Bi-Grid core, and the failure modes of the Tri-Grid, Quadri-Grid and Kagome-Grid are core shear. The mechanical performance of Quadri-Grid sandwich structure is better than that of the other three structures.

Original Article : Factors Predicting the Effi cacy of Adefovir Dipivoxil on Treatment-Naive Chronic Hepatitis B Patients at 48 Weeks

( Li Chun Wang ),( En Qiang Chen ),( Xiao Feng Zhu ),( Zhong Hua Xiong ),( Li Liu ),( Lu Xu ),( Xue Zhong Lei ),( Cong Liu ),( Hong Tang ) 대한간학회 2011 Gut and Liver Vol.5 No.4

Background/Aims: To reveal possible factors predicting the effect of adefovir dipivoxil (ADV) treatment on chronic hepatitis B (CHB) and optimize the utilization of ADV. Methods: In total, 168 treatment-naive CHB patients were enrolled, including 117 hepatitis B e antigen (HBeAg)-positive patients and 51 HBeAg-negative patients who met the inclusion criteria. All patients were treated with ADV 10 mg per day for 48 weeks. Multiple logistic regression analyses were used to investigate baseline factors, and responses at weeks 12 and 24 were analyzed as predictive values. Results: Multiple regression analyses showed that baseline HBeAg status and HBV DNA levels signifi cantly affected the virological response (VR) (p<0.05), baseline ALT levels were an independent predictor of serological response (SR) (p<0.05) and the body mass index (BMI) may affect the biochemical response (BR) (p<0.05). There was a statistically significant difference in the VR and SR between patients with a primary nonresponse (PNR) at week 12 and those with a VR at week 12 (p<0.01). Additionally, the VR was significantly different between patients with HBV DNA lower than 103 copies/mL at week 24 and those with greater than 103 copies/mL (p<0.01). Conclusions: Patients with negative HBeAg, lower HBV DNA levels and higher ALT values at baseline are more suitable for ADV treatment, whereas patients with lower BMIs may be more amenable to ALT normalization. Adjustments for treatment strategy should be considered if PNR at week 12 or HBV DNA ≥103 copies/mL at week 24 is observed. (Gut Liver 2011;5:478-485)

Control Strategy and Characteristic Analysis of Hybrid Active Power Filters with the Resonant Impedance Principle

Fang, Lu,Xu, Xian-Yong,Luo, An,Li, Yan,Tu, Chun-Ming,Fang, Hou-Hui The Korean Institute of Power Electronics 2012 JOURNAL OF POWER ELECTRONICS Vol.12 No.6

A new kind of resonant impedance type hybrid active filter (RITHAF) is proposed for dynamic harmonic current suppression and high capacity reactive compensation in medium and high voltage systems. This paper analyzed the different performance of the RITHAF when the active part of the RITHAF is controlled as a current source and as a voltage source, respectively. The harmonic suppression function is defined in this paper. The influences of the changes caused by the grid impedance and the detuning of the passive power filter on the compensating characteristics of the RITHAF are studied by analyzing the suppression function. Simulation and industrial application results show that the RITHAF has excellent performances in harmonic suppression and reactive compensation, which is suitable for medium and high voltage systems.

Microstructure Refi nement and Strengthening Mechanisms of a 9Cr Oxide Dispersion Strengthened Steel by Zirconium Addition

Haijian Xu,Zheng Lu,Dongmei Wang,Chun Ming Liu 한국원자력학회 2017 Nuclear Engineering and Technology Vol.49 No.1

To study the effects of zirconium (Zr) addition on the microstructure, hardness and the tensile properties of oxide dispersion strengthened (ODS) ferriticemartensitic steels, two kinds of 9Cr-ODS ferriticemartensitic steels with nominal compositions (wt.%) of Fe-9Cr- 2W-0.3Y2O3 and Fe-9Cr-2W-0.3Zr-0.3Y2O3 were fabricated by the mechanical alloying (MA) of premixed powders and then consolidated by hot isostatic pressing (HIP) techniques. The experimental results showed that the average grain size decreases with Zr addition. The trigonal d-phase Y4Zr3O12 oxides and body-centered cubic Y2O3 oxides are formed in the 9Cr-Zr-ODS steel and 9Cr non-Zr ODS steel, respectively, and the average size of Y4Zr3O12 particles is much smaller than that of Y2O3. The dispersion morphology of the oxide particles in 9Cr-Zr-ODS steel is significantly improved and the number density is 1.1 × 1023/m3 with Zr addition. The 9Cr-Zr-ODS steel shows much higher tensile ductility, ultimate tensile strength and Vickers hardness at the same time.

Four Human Cases of Diphyllobothrium nihonkaiense (Eucestoda: Diphyllobothriidae) in China with a Brief Review of Chinese Cases

Yu-Chun Cai,Shao-Hong Chen,Hiroshi Yamasaki,Jia-Xu Chen,Yan Lu,Yong-Nian Zhang,Hao Li,Lin Ai,Hai-Ning Chen 대한기생충학열대의학회 2017 The Korean Journal of Parasitology Vol.55 No.3

An investigation of the ferroelectric and magnetic properties of Nd-doped Bi1 − xNdxFeO3 polycrystalline ceramics fabricated by a sol-gel technique

Chang Chun Chen,Zhonghai Tang,Gui Wang,Chunhua Lu,Zhongzi Xu 한양대학교 세라믹연구소 2012 Journal of Ceramic Processing Research Vol.13 No.2

Nd-modified Bi1 − xNdxFeO3 (x = 0, 0.05, 0.1, and 0.15) ceramics were fabricated by a sol-gel method. The crystal structures of Nd-modified Bi1 − xNdxFeO3 (x = 0, 0.05, 0.1, and 0.15) ceramics were analyzed by X-ray diffraction (XRD). The effects of the Nd content on the ferroelectric, dielectric, and magnetic properties of these Bi1 − xNdxFeO3 ceramics were thoroughly investigated. The XRD patterns indicated that with an increase of the Nd doped content in Bi1 − xNdxFeO3 ceramics, the unwanted impurity phases such as Bi2Fe4O9 and Bi36Fe24O57 are markedly decreased. Clear polarization-electric field (P-E)hysteresis loops were observed for all the Nd-modified Bi1 − xNdxFeO3 ceramics and the shape of the P-E loop of the Bi1 − xNdxFeO3 ceramics was significantly improved due to the Nd substitution. In addition, slim magnetic hysteresis (M-H)loops in the Bi1 − xNdxFeO3 ceramics were also observed, and the saturated magnetization (Ms) of the Bi1 − xNdxFeO3 ceramics also increased with an increase of the Nd content.