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24 results on '"Zou Li-hua"'

8. Novel Alkaloids from Aspergillus fumigatusVDL36, an Endophytic Fungus Associated with Vaccinium dunalianum

Author

Wang, Wei-Hua, Li, Chu-Ran, Qin, Xu-Jie, Yang, Xiao-Qin, Xie, Si-Da, Jiang, Qian, Zou, Li-Hua, Zhang, Ying-Jun, Zhu, Guo-Lei, and Zhao, Ping

Abstract

Eleven alkaloids (1–11) including seven new ones, 1–7, were isolated from the solid fermentation of Aspergillus fumigatusVDL36, an endophytic fungus isolated from the leaves of Vaccinium dunalianumWight (Ericaceae), a perennial evergreen shrub distributed across the Southwest regions of China, Myanmar, and Vietnam. Their structures were elucidated on the basis of extensive spectroscopic methods. The isolates were evaluated for in vitroantifungal activities against five phytopathogenic fungi (Fusarium oxysporum, Coriolus versicolor, Fusarium solani, Botrytis cinerea, Fusarium graminearum). As a result, the new compounds fumigaclavine I (1), 13-ethoxycyclotryprostatin A (5), 13-dehydroxycyclotryprostatin A (6), and 12β-hydroxy-13-oxofumitremorgin C (7) exhibited antifungal activities with MIC values of 7.8–62.5 μg/mL which were comparable to the two positive controls ketoconazole (MIC = 7.8–31.25 μg/mL) and carbendazim (MIC = 1.95–7.8 μg/mL). Furthermore, compounds 1and 5demonstrated potent protective and curative effects against the tomato gray mold in vivo. Preliminary structure–activity relationships of the tested indole diketopiperazine alkaloids indicate that the introduction of a substituent group at position C-13 enhances their biological activities.

Published
2024
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12. Grey forecasting model for active vibration control systems

Author

Bo Dong, John Butterworth, Zou Li-hua, Xing Ma, Aiping Liu, and Dai Suliang

Subjects
Ground motion, Engineering, Acoustics and Ultrasonics, business.industry, Mechanical Engineering, Vibration control, State vector, Sampling (statistics), Condensed Matter Physics, Optimal control, Model predictive control, Mechanics of Materials, Control theory, Active vibration control, Structural vibration, business, Physics::Atmospheric and Oceanic Physics
Abstract

Based on the grey theory, a GM(1,1) forecasting model and an optimal GM(1,1) forecasting model are developed and assessed for use in active vibration control systems for earthquake response mitigation. After deriving equations for forecasting the control state vector, design procedures for an optimal active control method are proposed. Features of the resulting vibration control and the influence on it of time-delay based on different sampling intervals of seismic ground motion are analysed. The numerical results show that the forecasting models based on the grey theory are reliable and practical in structural vibration control fields. Compared with the grey forecasting model, the optimal forecasting model is more efficient in reducing the influences of time-delay and disturbance errors.

Published
2009
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15. Triterpenoid saponins from the buds of Lonicera similis.

Author

Zhang, Xiao, Zou, Li-Hua, He, Yu-Lin, Peng, Cheng, Guo, Li, and Xiong, Liang

Abstract

Four new lupane triterpenoid saponins, along with one known lupane and eight hederagenin saponins, were isolated from the EtOH extract of the buds of Lonicera similis Hemsl. The structures of the new compounds were established as 3-O-β-D-glucopyranosyl-(1→2)-β-D-glucopyranosyl 23-hydroxybetulinic acid 28-O-β-D-glucopyranosyl ester (lonisimilioside A, 1), 3-O-β-D-glucopyranosyl-(1→2)-β-D-glucopyranosyl 23-hydroxybetulinic acid 28-O-β-D-glucopyranosyl-(1→6)-β-D-glucopyranosyl ester (lonisimilioside B, 2), 3-O-β-D-glucopyranosyl-(1→2)-β-D-glucopyranosyl betulinic acid 28-O-β-D-glucopyranosyl-(1→6)-β-D-glucopyranosyl ester (lonisimilioside C, 3) and 3-O-β-D-glucopyranosyl-(1→2)-β-D-glucopyranosyl-(1→6)-β-D-glucopyranosyl betulinic acid 28-O-β-D-glucopyranosyl ester (lonisimilioside D, 4), respectively. The cytotoxic activities of the isolates against human cancer cell lines HepG2, MCF-7 and A-549 were evaluated. Only the monodesmosidic saponin with a free carboxyl group at C-28 (12) exhibited significant cytotoxicities against HepG2, MCF-7 and A-549 cell lines with the IC50 values of 8.98 ± 0.19, 12.48 ± 0.45 and 11.62 ± 0.54 μM, respectively. Furthermore, Hoechst fluorescence 33342 staining was used to demonstrate that 12 could induce HepG2 and A-549 cells apoptosis significantly. [ABSTRACT FROM AUTHOR]

Published
2018
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16. Optimization Design of PID Controller and its Application

Author

Li Xiang Fei and Zou Li Hua

Subjects
Engineering, business.industry, MathematicsofComputing_NUMERICALANALYSIS, Open-loop controller, Pendulum, PID controller, ComputerApplications_COMPUTERSINOTHERSYSTEMS, Control engineering, Performance index, Chaos optimization, Computer Science::Systems and Control, Robustness (computer science), Control theory, Control system, Process control, business, Computer Science::Operating Systems
Abstract

PID control has been largely applied in the industry process control because of its robustness and easy realization, But it is very difficult to tune the three parameters of PID controller, which often leads to oscillation and overshoot of the controlled object. Due to no repetition and random of chaos dynamics, a method to search for PID controller parameters based on chaos variable is proposed according to the performance index of control system. and then by which practicality pendulum is controlled. Experiment results show that the method is efficient to realize self-tuning parameters of PID controller, provides an effective way for optimization design of PID controller.

Published
2011
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