Molecular characterization of a phospholipid-hydroperoxide glutathione peroxidase from the bumblebee Bombus ignitus

Zhigang Hu,Kwang Sik Lee,Young Moo Choo,Yu Xin,Hyung Joo Yoon,Iksoo Kim,Hung Dae Sohn,Byung Rae Jin 한국응용곤충학회 2009 한국응용곤충학회 학술대회논문집 Vol.2009 No.10

Phospholipid-hydroperoxide glutathione peroxide (PHGPx) is an antioxidant enzyme that reduces lipid hydroperoxides in biomembranes. Here, we cloned and characterized cys-PHGPx from the bumblebee Bombus ignitus (Bi-PHGPx). The Bi-PHGPx gene consists of 4 exons, encoding 168 amino acid residues with a canonical cys-codon at residue 45 and active site residues Gln82 and Trp134. Recombinant Bi-PHGPx, expressed as a 19 kDa protein in baculovirus-infected insect cells, exhibited enzymatic activity against PLPC-OOH and H2O2 using glutathione as an electron donor. Tissue distribution analyses showed the presence of Bi-PHGPx in all tissues examined. Bi-PHGPx transcripts were upregulated by stresses, such as wounding, H2O2 exposure, external temperature shock, and starvation. Under H2O2 overload, the RNA interference (RNAi)-induced thioredoxin peroxidase (BiTPx1)-knock-down B. ignitus worker bees showed upregulated expression of Bi-PHGPx in the fat body. These results indicate that Bi-PHGPx is a stress-inducible antioxidant enzyme that acts on phospholipid hydroperoxide and H2O2.

An Experimental Study on Behaviour of Reinforced Concrete T-shaped Columns Subjected to Combined Loads

Zhigang Yu,Deshan Shan 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.3

Reinforced concrete girders of curved cable-stayed bridges are subjected to the combined loads of compression-bending-shear-torsion, which can result in complex interaction behaviours. This paper presents an experimental study conducted to understand the behaviours of T-shaped reinforced concrete columns subjected to the combined loads of compression-bending-shear-torsion. The main variables considered in this study are axial pressure ratio and torsional change. The results of tests on twelve reinforced concrete columns subjected to the combined loads are obtained, and the effects of combined loads on the bending strength are discussed. This paper presents the formula established for calculating the bending strength and the diagrams of interaction under the combined loads of compression-bending-shear-torsion. Particularly, the results highlight the turning point from the bending failure to the compression failure, and demonstrate that bending capability increases within the specified range of axial pressure ratio and decreases with the increasing torsion. In addition, this study indicates the importance of considering the effects of compression, shear and torsion on bending strength in the engineering design.

Fine Mapping of a Foot-and-Mouth Disease Virus Epitope Recognized by Serotype-Independent Monoclonal Antibody 4B2

Yongzhong Yu,Haiwei Wang,Lei Zhao,Chunyuan Zhang,Zhigang Jiang,Li Yu 한국미생물학회 2011 The journal of microbiology Vol.49 No.1

VP2 is a structural protein of the foot-and-mouth disease virus (FMDV). In this study, a FMDV serotype-independent monoclonal antibody (MAb), 4B2, was generated. By screening a phage-displayed random 12-peptide library, we found positive phages displaying the consensus motif ETTXLE (X is any amino acid (aa)), which is highly homologous to ^6ETTLLE^11 at the N-terminus of the VP2 protein. Subsequently, a series of GST-fusion proteins expressing a truncated N-terminus of VP2 were examined by western blot analysis using the MAb 4B2. The results indicated that the motif ^6ETTLLE^11 of VP2 may be the minimal requirement of the epitope recognized by 4B2. Moreover, a 12-aa peptide ^2KKTEETTLLEDR^13 was shown to be the minimal unit of the epitope with maximal binding activity to 4B2. Alanine-scanning analysis demonstrated thatThr^7, Thr^8, and Leu^10 are the functional residues of the 4B2 epitope Glu^6 and Leu^9 are required residues, and Glu^11 plays a crucial role in the binding of MAb 4B2. The fine mapping of the epitope indicated that MAb 4B2 has the potential to be used in FMDV diagnosis.

Identification of tyrosine 71 as a critical residue for the cytotoxic activity of Clostridium perfringens epsilon toxin towards MDCK cells

Zhigang Jiang,Jitao Chang,Fang Wang,Li Yu 한국미생물학회 2015 The journal of microbiology Vol.53 No.2

Clostridium perfringens epsilon toxin (Etx) is an extremely potent toxin, causing fatal enterotoxaemia in many animals. Several amino acids in domains I and II have been proposed to be critical for Etx to interact with MDCK cells. However, the critical amino acids in domain III remain undefined. Therefore, we assessed the effects of aromatic amino acids in domain III on Etx activity in this study. All of the results indicated that Y71 was critical for the cytotoxic activity ofEtx towards MDCK cells, and this activity was dependent on the existence of an aromatic ring residue in position 71. Additionally, mutations in Y71 did not affect the binding of Etx to MDCK cells, indicating that Y71 is not a receptor binding site for Etx. In summary, we identified an amino acid in domain III that is important for the cytotoxic activity of Etx, thereby providing information on the structure-function relationship of Etx.

A High-Precision Calibration Method for MEMS Gyroscopes

Zhigang Shang,Xiaochuan Ma,Mo Li,Yu Liu 한국정밀공학회 2015 International Journal of Precision Engineering and Vol. No.

MEMS (Micro-Electromechanical Systems) gyroscopes are widely used in many industrial products. However, observations often include many errors because of being not precisely calibrated and effectively compensated. This paper first proposes the idea that the excitation signal is designed using Persistent Excitation Signal Criterion in the modern control theory. The cosine angular velocity signal is selected as the excitation signal and proved to be Persistent Excitation Signal. The calibration scheme and data-acquisition program are proposed. Cross-correlation algorithm is used to solve calibration parameters. In order to verify the effectiveness and stability of the proposed calibration, we conduct simulations and in-depth discussions. Considering the temperature features of MEMS gyroscopes, the temperature control turntable is chosen to generate the excitation signal. Then we take turns to calibrate the parameters by the traditional method and the proposed method. The verification experiment is designed and implemented to verify the accuracy of calibration parameters. The results of the comparison and verification experiment show that the proposed method is an efficient and simple high-precision calibration method.

Study on Multi Objective Optimization Method and It Application in Aviation and Deceleration Device

Yu Guang-bin,Song Ye,Duan Yuan-wang,Zhao Xing-fu,Qu Zhigang,Sun Yong-guo 보안공학연구지원센터 2016 International Journal of Smart Home Vol.10 No.5

Calcification Remodeling Index Characterized by Cardiac CT as a Novel Parameter to Predict the Use of Rotational Atherectomy for Coronary Intervention of Lesions with Moderate to Severe Calcification

Mengmeng Yu,Yuehua Li,Wenbin Li,Zhigang Lu,Meng Wei,Jiayin Zhang 대한영상의학회 2017 Korean Journal of Radiology Vol.18 No.5

Objective: To assess the feasibility of calcification characterization by coronary computed tomography angiography (CCTA) to predict the use of rotational atherectomy (RA) for coronary intervention of lesions with moderate to severe calcification. Materials and Methods: Patients with calcified lesions treated by percutaneous coronary intervention (PCI) who underwent both CCTA and invasive coronary angiography were retrospectively included in this study. Calcification remodeling index was calculated as the ratio of the smallest vessel cross-sectional area of the lesion to the proximal reference luminal area. Other parameters such as calcium volume, regional Agatston score, calcification length, and involved calcium arc quadrant were also recorded. Results: A total of 223 patients with 241 calcified lesions were finally included. Lesions with RA tended to have larger calcium volume, higher regional Agatston score, more involved calcium arc quadrants, and significantly smaller calcification remodeling index than lesions without RA. Receiver operating characteristic curve analysis revealed that the best cutoff value of calcification remodeling index was 0.84 (area under curve = 0.847, p < 0.001). Calcification remodeling index ≤ 0.84 was the strongest independent predictor (odds ratio: 251.47, p < 0.001) for using RA. Conclusion: Calcification remodeling index was significantly correlated with the incidence of using RA to aid PCI. Calcification remodeling index ≤ 0.84 was the strongest independent predictor for using RA prior to stent implantation.

Three-dimensional Adaptive Sliding Mode Guidance Law for Missile with Autopilot Lag and Actuator Fault

Guiying Li,Zhigang Yu,Zhongxian Wang 제어·로봇·시스템학회 2019 International Journal of Control, Automation, and Vol.17 No.6

This paper investigates guidance scheme for missile with actuator failure and dynamics of autopilot. Firstly, considering first-order dynamics of autopilot, the guidance model with actuator failure is established. Secondly, an adaptive sliding mode fault-tolerant guidance law is designed on the basis of passive fault-tolerant technique and a novel nonsingular fast terminal sliding mode (NFTSM) manifold. Then, the adaptive algorithm with the feature of low-pass filter is proposed to ensure that adaptive parameters are bounded when the sliding mode is non-ideal. Finally, Lyapunov stability theory is adopted to prove that the states of closed-loop system are practical finite-time stability. Simulation results demonstrate the effectiveness and robustness of the proposed guidance strategy under the certain actuator failure.

Dynamic Characteristic Simulation of Helicopter Tail Drive Shaft System

Nie Junfeng,Yu Guangbin,Song Ye,Qu Zhigang,Zheng Minli,Zhao Xingfu 보안공학연구지원센터 2016 International Journal of Smart Home Vol.10 No.6

Helicopter with the advantage of light, flexible and hovering in the air, is widely used. In both military and civilian domain, it gets more and more attention. It becomes the main subject of research in the world. In the power transmission system of helicopter, the tail rotor shaft is an important part. It is one of the key technologies to predict the dynamic characteristics of the shaft accurately for improving the overall performance of the helicopter. Based on the theory of elastic mechanics, rotor dynamics and the finite element analysis, the former main drive shaft is taken as an example. The dynamic characteristics of the transmission shaft is calculated by the multi/few degrees of freedom finite element method. The validity of the finite element method with few degrees of freedom is determined. Then the structure characteristics of the helicopter tail drive shaft are analyzed, and the dynamic characteristics of the helicopter tail rotor shaft are calculated by using the finite element method with few degrees of freedom. The research results provide the basis and guidance for the design of the helicopter tail drive system.

Research on Nonlinear Vibration Characteristics of Spiral Bevel Gear

Nie Junfeng,Yu Guangbin,Song Ye,Qu Zhigang,Zheng Minli,Zhao Xingfu 보안공학연구지원센터 2016 International Journal of Multimedia and Ubiquitous Vol.11 No.2

Based on the concentrated parameters theory, a 7-freedom coupled vibration dynamic model of the spiral bevel gear transmission system is established, which includes transmission error, time-varying mesh stiffness and the tooth backlash clearance. In the model, the axial vibration, the torsion oscillation of the gear pair aroused by tooth meshing force and the lateral oscillations resulting from flexional deformation of the gear shaft are taken into account. The mesh stiffness fluctuation is developed as 5-order Fourier series and the tooth backlash clearance is fitted by 7-order polynomial function. Through the Gear method, the dynamic response of the system is obtained, and the vibration characteristics are analyzed.