Expression, purification and enzymatic properties of a β-Nacetylhexosaminidase from brown planthopper, Nilaparvata lugens

Yunhua Zhang,Jinyun Ji,Xiao Zhao,Ruoheng Jin,Jian Hong Li,Hu Wan 한국응용곤충학회 2017 Journal of Asia-Pacific Entomology Vol.20 No.4

A previous study demonstrated that a β-N-acetyl-D-hexosaminidase (NlHex4) from the brown planthopper could serve as a new potential target for biopesticides due to its requirement for molting, and lethal phenotypes were observed via RNA interference. However, the enzymatic properties of NlHex4 remain unclear. In the present study, NlHex4 was expressed, purified and characterized. Recombinant NlHex4 was functionally expressed in baculovirus-infected insect cells and purified with a molecular weight of approximately 70 kDa. Recombinant NlHex4 had an optimal pH and temperature of 6.0 and 60 °C, respectively. Moreover, recombinant NlHex4 exhibited thermal stability at 50 °C for at least 1 h. Furthermore, the activity of recombinant NlHex4 was inhibited by the metal ions Fe2+ and Fe3+ and the serine protease inhibitor phenylmethanesulfonyl fluoride. These results reveal the enzymatic properties of NlHex4 and provide a basis for future investigation of the interaction between HEX and chitin oligosaccharide.

Functional profiling of the gut microbiomes in two different populations of the brown planthopper, Nilaparvata lugens

Yunhua Zhang,Tao Tang,Wenhao Li,Tingwei Cai,Jian Hong Li,Hu Wan 한국응용곤충학회 2018 Journal of Asia-Pacific Entomology Vol.21 No.4

Previous studies have demonstrated that gut symbionts are involved in the detoxification metabolism of insect hosts, but the relationship between gut symbionts and host detoxification metabolism of the brown planthopper (Nilaparvata lugens, BPH) remains unclear. In the present study, an indoor population (NlIP) and a field population (NlFP) of the BPH were used to characterize the functional profiling of the gut microbiome based on 16S rDNA sequencing. The results show that the NlIP and NlFP strains of N. lugens had different symbiont compositions, and Proteobacteria, Actinobacteria, and Firmicutes were the dominate phyla, accounting for > 75% of the total symbiont compositions. Additionally, the NlIP strain had more Pantoea and Stenotrophomonas, while the NlFP strain showed a higher Wolbachia, Actinobacteria, and Herbaspirillum relative abundance. Furthermore, functional content of the metagenome predicted by PICRUSt demonstrated no significant difference in metagenomic function between the NlIP and NlFP strains in the principal component analysis (PCA), and only three types of genes, namely, genes involved with metabolic diseases, poorly characterized genes, and genes involved in circulatory systems, were different between the strains based on KEGG pathway analysis, which also speculated that gut symbionts are not directly involved in the detoxification metabolism for insecticides in the BPH. These results will be helpful for further research into the mechanisms of gut symbionts involved in detoxification metabolism in the BPH.

RFID Indoor Localization Algorithm Based on Adaptive Self-Correction

Yunhua Gu,Junyong Zhang,Jin Wang,Bao Gao,Jie Du 보안공학연구지원센터 2014 International Journal of Smart Home Vol.8 No.6

With the rapid development of wireless communication and embedded system, wireless positioning systems are paid more and more attention to. Radio Frequency Identification (RFID) localization system is getting more important, due to its own advantages, such as no contact, non-line-of-sight nature, promising transmission range and cost-effectiveness. To improve the accuracy of active RFID indoor location system, some traditional RFID indoor localization systems were studied, such as LANDMARC. On this basis, an adaptive self-correction location algorithm was presented, which uses a positioning correction value to correct the positioning result. N minimum errors and position results are obtained by using adaptive K-nearest neighbor algorithm N times. The positioning correction value calculated with N minimum errors in weighted way. The sum of the positioning average value and the positioning correction value would be the final positioning results. Experimental results show that compared with adaptive K-nearest neighbor algorithm and error self-correction algorithm, the proposed method provides a higher accuracy and stability.

Isolation and characterization of a novel gossypol-degrading bacteria Bacillus subtilis strain Rumen Bacillus Subtilis

Yunhua Zhang,Zhengyou Zhang,Li Dai,Ying Liu,Maoji Cheng,Lijuan Chen 아세아·태평양축산학회 2018 Animal Bioscience Vol.31 No.1

Objective: The aim of the study was to isolate gossypol-degrading bacteria and to assess its potential for gossypol degradation. Methods: Rumen liquid was collected from fistulated cows grazing the experimental pasture. Approximately 1 mL of the rumen liquid was spread onto basal medium plates containing 2 g/L gossypol as the only source of carbon and was then cultured at 39°C to isolate gossypol-degrading bacteria. The isolated colonies were cultured for 6 h and then their size and shape observed by microscope and scanning electron microscope. The 16S rRNA gene of isolated colonies was sequenced and aligned using National Center for Biotechnology Information-Basic Local Alignment Search Tool. The various fermentation conditions, initial pH, incubation temperature, inoculum level and fermentationperiod were analyzed in cottonseed meal (CSM). The crude protein (CP), total gossypol (TG), and free gossypol (FG) were determined in CSM after fermentation with isolated strain at 39°C for 72 h. Results: Screening results showed that a single bacterial isolate, named Rumen Bacillus Subtilis (RBS), could use gossypol as a carbon source. The bacterium was identified by 16S rDNA sequencing as being 98% homologous to the sequence of Bacillus subtilis strain GH38. The optimum fermentation conditions were found to be 72 h, 39°C, pH 6.5, moisture 50%, inoculum level 107 cell/g. In the optimum fermentation conditions, the FG and TG content in fermented CSM decreased 78.86% and 49% relative to the control. The content of CP and the essential amino acids of the fermented CSM increased respectively, compared with the control. Conclusion: The isolation of a gossypol-degrading bacterium from the cow rumen is of great importance for gossypol biodegradation and may be a valuable potential source for gossypol-degradation of CSM.

Utilization of electron beam to modulate electron injection over Schottky barrier

Qi Zhang,Junjie Qi,Yunhua Huang,Huifeng Li,Xin Li,Ruoshui Wang,Yue Zhang 한국물리학회 2011 Current Applied Physics Vol.11 No.3

Modulation of electron injection over Schottky barrier was realized by employing electron beam irradiation on the metal/ZnO-nanowire contact. The structure revealed a good response to the illumination at a scanning frequency of 0.1 Hz, which can be enhanced by increasing bias and decreased with the increase of electron beam energy. These phenomena can be attributed to the Schottky barrier formed at the metal/ZnO-nanowire interface which limits the electron transport across the contact. The electron beam irradiation gives rise to high efficiency of electron injection over the barrier, while the interplay between charge discreteness, coherent scattering, and Coulomb interaction may reduce the conductivity.

A RFID Data-Cleaning Algorithm Based on Communication Information among RFID Readers

Yunhua Gu,Bao Gao,Jin Wang,Mingshu Yin,Junyong Zhang 보안공학연구지원센터(IJUNESST) 2015 International Journal of u- and e- Service, Scienc Vol.8 No.1

For the insufficient of existing algorithms of redundant-reader elimination, the paper proposes a data-cleaning algorithm based on communication information among readers. This algorithm is no longer dependent on the tag to send information between the RFID readers, but to transmit information directly through communication information among the readers to determine which reader the tag belongs to and whether the reader is redundant or not. This paper does a lot of experiments to verify the effectiveness of the algorithm.

Preliminary Simulation on Spaceborne Sparse Array Millimeter Wave Radar for GMTI

Xueyan Kang,Yunhua Zhang 한국전자파학회JEES 2010 Journal of Electromagnetic Engineering and Science Vol.10 No.4

Spaceborne sparse array radar for ground moving targets indication (GMTI) has outstanding advantage over full array radar for constructing ultra-large aperture. Rapid development of millimeter wave (MMW) technology make it possible for realizing MMW GMTI radar, which is much more sensitive to slow moving ground target. The paper presented the system model of a multi-carrier frequency sparse array MMW radar as well as preliminary simulation results, which showed future application of the system is very promising.

DenSleepNet: DenseNet based model for sleep staging with two‑frequency feature fusion and coordinate attention

Zhi Liu,Meiqiao Qin,Yunhua Lu,Sixin Luo,Qinhan Zhang 대한의용생체공학회 2023 Biomedical Engineering Letters (BMEL) Vol.13 No.4

Sleep staging is often applied to assess the quality of sleep and also be used to prevent and monitor psychiatric disorderscaused by sleep. However, it remains a challenge to extract the discriminative features of salient waveforms in sleep EEG andenable the network to effectively classify sleep stages by emphasizing these crucial features, thus achieving higher accuracy. In this study, an end-to-end deep learning model based on DenseNet for automatic sleep staging is designed and constructed. In the framework, two convolutional branches are devised to extract the underlying features (Two-Frequency Feature) at variousfrequencies, which are then fused and input into the DenseNet module to extract salient waveform features. After that,the Coordinate Attention mechanism is employed to enhance the localization of salient waveform features by emphasizingthe position of salient waveforms and the spatial relationship across the entire frequency spectrum. Finally, the obtainedfeatures are accessed to the fully connected for sleep staging. The model was validated with a 20-fold cross-validation procedureon two public available datasets, and the overall accuracy, kappa coefficient, and MF1 score reached 92.9%, 78.7, 0.86and 90.0%, 75.8, 0.80 on Sleep-EDF-20 and Sleep-EDFx, respectively. Experimental results show that the proposed modelachieves competitive performance for sleep staging compared with the reported approaches under the identical conditions.

Efficacy of an adhesive nanopesticide on insect pests of rice in field trials

Gao Yunhao,Li Donglin,Li Dongyang,Xu Pengfei,Mao Kaikai,Zhang Yunhua,Qin Xueying,Tang Tao,Wan Hu,Li Jianhong,Guo Mingcheng,He Shun 한국응용곤충학회 2020 Journal of Asia-Pacific Entomology Vol.23 No.4

Nanopesticides with antiwashing capacity on leaves are the most promising new approaches for sustainable pest management and have been fully evaluated in the laboratory. However, few studies have tested these nanopesticides on pests, and their efficacy under field conditions has not been investigated. In this study, an adhesive hollow mesoporous silica hybrid with well-defined spherical shape and good monodispersity was used as a nanocarrier of cyantraniliprole (CNAP) to fabricate an adhesive nanopesticide (CNAP-HMS-PDAAM). The control efficacy of CNAP-HMS-PDAAM was tested under field conditions. The results indicated that the efficacy of four doses of CNAP-HMS-PDAAM (30.0–69.0 g a.i./ha) against Cnaphalocrocis medinalis (Guénee) 3, 7, and 14 days after spraying did not significantly differ from that of Benevia (34.5 g a.i./ha). Twenty-eight days after spraying, the efficacy of all four doses of CNAP-HMS-PDAAM was significantly better than that of Benevia. Additionally, the efficacy of CNAP-HMS-PDAAM at doses of 34.5, 39.0 and 69.0 g a.i./ha against Chilo suppressalis (Walker) were significantly higher than that of Benevia (34.5 g a.i./ha). Thus, CNAP-HMS-PDAAM showed long-term control efficacies against C. medinalis (Guénee) and C. suppressalis (Walker), mainly due to its strong adhesive property on rice leaves and its sustained release properties. In addition, the nanocarriers showed good biocompatibility and had no obvious influence on the growth of rice.

Fluorinated and Charged Non-woven Polypropylene Electret Fiber Membrane: A Novel Way in Transformer Oil Regeneration

Nianrong Zhou,Xiao He,Yuyang Yan,Xinliang Guo,Linshan Zhang,Yunhua He,Xiangyu Tan,Zhengyun Fang 한국전기전자재료학회 2022 Transactions on Electrical and Electronic Material Vol.23 No.2

The regeneration of transformer oil is a trending topic in the dielectric research field. However, the normal way of regeneration requires high cost and complicate process. In this paper, the non-woven polypropylene (PP) electret films were modifi ed by fluorination and corona method to achieve the regeneration function for transformer oil. The results show that the C-H bonds in polypropylene were replaced by C-F bonds during the fluorination process, resulting in the mean diameter of the fibers being decreased to a value of 1.7 μm. The increased roughness of the fi bers leads to super hydrophobicity. Further research revealed that the insulation properties of aging oil recovered after fi ltration by corona charged fl uorinated fi ber membranes. The result is especially signifi cant for breakdown voltage, the values of which reached half of the original insulating oil. In conclusion, the combination of fl uorinating and corona charging method on PP fi ber membrane shows great potential for insulation oil regeneration.