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Guangzhi Li,Junchi Wang,Xiaojin Li,Jianguo Xu,Zhao Zhang,Jianyong Si 대한약학회 2018 Archives of Pharmacal Research Vol.41 No.6
20-Z auraptene (1) is a synthesized monoterpenecoumarin with anticancer activity against human gastriccancer cells. In order to find new potential anticancer agent,Mucor polymorphosporus was used to transform cis-auraptene. Four new terpene coumarins with notable changesin the skeletal backbone, 20-Z auraptene A-D (2–5), wereobtained and evaluated for their antiproliferative effectsagainst human normal gastric epithelium cells and humangastric cancer cells. These new compounds showed selectivecytotoxic activity against MGC-803 cells with IC50values from 0.78 ± 0.13 to 10.78 ± 1.83 lM and thetherapeutic index could also be significantly improved(TI = 59.0) compared with that of 1 (TI = 5.5). Thestructures of these metabolites were elucidated throughextensive spectroscopic methods, and the possible biotransformationpathway of 1 by Mucor polymorphosporuswas also proposed. Furthermore, the mechanism of theantiproliferative effects against MGC-803 cells of the mostpotent compound, 20-Z auraptene A (2), was characterized. Annexin V/PI staining and abnormal expression of apoptosis-related protein suggested that compound 2 inducesapoptosis in gastric cancer MGC-803 cells. Therefore, it ispossible that compound 2 has the potential to be applied ingastric cancer therapy.
Zhiyi Li,You Du,Yiwei Zhao,Guanfeng Lin,Haoran Zhang,Chenkai Li,Xiaohan Ye,Yang Yang,Shengru Wang,Jianguo Zhang 대한척추신경외과학회 2023 Neurospine Vol.20 No.4
Objective: To compare the radiological outcomes in Lenke 5C type patients whose lowest instrumented vertebra (LIV) was L3 or L4 in a case-match study. Methods: We conducted a retrospective case-match study and included 82 patients in the study. Radiological results before surgery, after surgery, and at last follow-up were recorded and analyzed in the L3 and L4 groups. Results: After matching the age, Risser’s sign, sex, and main Cobb, 41 pairs of patients were enrolled in our study. The total fusion segments in the L3 group (median [interquartile range]: 5.0 [6.0–5.0]) were shorter than those in the L4 group (6.0 [6.5–6.0]). The main curve was significantly corrected after surgery in both groups, and was comparable at the last followup between groups. In addition, according to the results of Fisher precision probability test, there was no significant difference of coronal or sagittal imbalance between the 2 groups at the 2-year follow-up. Conclusion: The correction in coronal and sagittal planes in L3 group and L4 group remains similar. On account of more motion segments, L3 could be an ideal choice as LIV in moderate Lenke 5C type AIS. Long-term follow-up is needed to evaluate the effect of larger compensatory lumbar-sacral curve when stopping at L3.
Jianguo Zhang,Andreas Rosenkranz,Junjie Zhang,Jiang Guo,Xiaoqing Li,Xiao Chen,Junfeng Xiao,Jianfeng Xu 한국정밀공학회 2022 International Journal of Precision Engineering and Vol.9 No.5
Hardened steel is an important material related to the development of modern industry branches. In order to satisfy the adhesion strength as well as the corrosion and wear resistance under extreme conditions, the modification of the wettability of hardened steel has become an important scientific topic. As micro/nano-structured surfaces play an essential role to induce advanced functional surfaces with wettability control, this contribution aims at presenting the feasibility of micro/nano sculpturing of hardened steels by elliptical vibration diamond cutting. The influence of the fabricated micro/nano structures on the resulting wettability is discussed and related to the contact line density as well as asperity heights. In this regard, it has been verified that a pitch value of 12 μm and structural height of 500 nm are the preferred structural parameters to increase the hydrophobicity of the textured steel specimens.
( Jianguo Duan ),( Nan Xie ),( Lianhui Li ) 한국인터넷정보학회 2020 KSII Transactions on Internet and Information Syst Vol.14 No.4
In the design of production system, buffer capacity allocation is a major step. Through polymorphism analysis of production capacity and production capability, this paper investigates a buffer allocation optimization problem aiming at the multi-stage production line including unreliable machines, which is concerned with maximizing the system theoretical production rate and minimizing the system state entropy for a certain amount of buffers simultaneously. Stochastic process analysis is employed to establish Markov models for repairable modular machines. Considering the complex structure, an improved vector UGF (Universal Generating Function) technique and composition operators are introduced to construct the system model. Then the measures to assess the system’s multi-state reliability and structural complexity are given. Based on system theoretical production rate and system state entropy, mathematical model for buffer capacity optimization is built and optimized by a specific genetic algorithm. The feasibility and effectiveness of the proposed method is verified by an application of an engine head production line.
Redundancy Reduction for Compressed Sensing based Random Equivalent Sampling Signal Reconstruction
Jianguo Huang,Li Wang,Yijiu Zhao 보안공학연구지원센터 2016 International Journal of Signal Processing, Image Vol.9 No.5
Random equivalent sampling (RES) can composite a waveform with high equivalent sampling rate from multiple low speed sampling sequences. In practical application, the performance of RES signal reconstruction would be degraded by the non-uniform distribution of sampling time. Compressed sensing (CS) theory is adopted to reconstruct RES samples, which could mitigate the inherent coherence of sampling time. However, the CS reconstruction algorithm is sensitive to the signal sparsity level that is unknown in the reconstruction stage. In this paper, we propose a redundancy reduction algorithm for CS base RES signal reconstruction that can ensure reconstruction accuracy while reducing the number of random samples. The experimental results are reported to evaluate the performance of the proposed algorithm.
Jianguo Liao,Yanqun Li,Xiali Guan,Jingxian Liu,Yongxiang Zhang,Yufen Xie,Zhengpeng Yang,Xingze Duan,Aiguo Zhou,Jiangnan Zhu 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2016 NANO Vol.11 No.10
Hydroxyapatite and strontium-substituted hydroxyapatite nanoparticles (n-HA and Sr-HA) were prepared by microwave-assisted solution synthesis with aqueous solutions of various Sr/(Sr+Ca) molar ratios ranging from 0% to 15%. The structural properties of the hydroxyapatite powders were investigated by X-ray powder diffraction, Fourier transform infrared spectroscopy and Raman spectra, field emission scanning electron microscopy coupled with energy dispersive X-ray spectrometry and transmission electron microscopy. The results confirmed that strontium ions had been incorporated into the hydroxyapatite lattice. The synthetic n-HA and Sr-HA nanocrystalline consisted of hydroxyapatite crystalline phase with hexagonal structure, and the particle size was 30–40 x 60–70 nm and 40–50 x 70–80 nm, respectively. The calcined HA particle size ranged from about 120 nm to 150 nm, the calcined Sr-HA products were composed of spherical aggregates with a size of about 70–100 nm. The incorporation of Sr ions lead to the formation of vacancies in the crystal structure of the HA. The results indicated that the strontium substitution did not change the crystal structures. More Sr resulted in less calcined crystallites and formed agglomerates owing to the size effect.
Li, Junjie,Jiang, Jianguo The Korean Institute of Power Electronics 2017 JOURNAL OF POWER ELECTRONICS Vol.17 No.3
Multilevel active neutral-point-clamped (ANPC) converter combines the advantages of three-level ANPC converter and multilevel flying capacitor (FC) converter. However, multilevel ANPC converter often suffers from capacitor voltage balancing problems. In order to solve the capacitor voltage balancing problems for five-level ANPC converter, phase-shifted pulse width modulation (PS-PWM) is used, which generally provides natural voltage balancing ability. However, the natural voltage balancing ability depends on the load conditions and converter parameters. In order to eliminate voltage deviations under steady-state and dynamic conditions, the active voltage-balancing control (AVBC) methods of floating capacitors and dc-link capacitors based on PS-PWM are proposed. First, the neutral-point current is regulated to balance the neutral-point voltage by injecting zero-sequence voltage. After that, the duty cycles of the redundant switch combinations are adjusted to balance the floating-capacitor voltages by introducing moderating variables for each of the phases. Finally, the effectiveness of the proposed AVBC methods is verified by experimental results.
Li, Junjie,Chang, Xiangyu,Yang, Dirui,Liu, Yunlong,Jiang, Jianguo The Korean Institute of Power Electronics 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.6
To achieve a fast dynamic response and to solve the multi-objective control problems of the output currents, capacitor voltages and system constraints, this paper proposes a deadbeat and hierarchical predictive control with space-vector modulation (DB-HPC-SVM) for five-level nested neutral point piloted (NNPP) converters. First, deadbeat control (DBC) is adopted to track the reference currents by calculating the deadbeat reference voltage vector (DB-RVV). After that, all of the candidate switching sequences that synthesize the DB-RVV are obtained by using the fast SVM principle. Furthermore, according to the redundancies of the switch combination and switching sequence, a hierarchical model predictive control (MPC) is presented to select the optimal switch combination (OSC) and optimal switching sequence (OSS). The proposed DB-HPC-SVM maintains the advantages of DBC and SVM, such as fast dynamic response, zero steady-state error and fixed switching frequency, and combines the characteristics of MPC, such as multi-objective control and simple inclusion of constraints. Finally, comparative simulation and experimental results of a five-level NNPP converter verify the correctness of the proposed DB-HPC-SVM.
Junjie Li,Jianguo Jiang 전력전자학회 2017 JOURNAL OF POWER ELECTRONICS Vol.17 No.3
Multilevel active neutral-point-clamped (ANPC) converter combines the advantages of three-level ANPC converter and multilevel flying capacitor (FC) converter. However, multilevel ANPC converter often suffers from capacitor voltage balancing problems. In order to solve the capacitor voltage balancing problems for five-level ANPC converter, phase-shifted pulse width modulation (PS-PWM) is used, which generally provides natural voltage balancing ability. However, the natural voltage balancing ability depends on the load conditions and converter parameters. In order to eliminate voltage deviations under steady-state and dynamic conditions, the active voltage-balancing control (AVBC) methods of floating capacitors and dc-link capacitors based on PS-PWM are proposed. First, the neutral-point current is regulated to balance the neutral-point voltage by injecting zero-sequence voltage. After that, the duty cycles of the redundant switch combinations are adjusted to balance the floating-capacitor voltages by introducing moderating variables for each of the phases. Finally, the effectiveness of the proposed AVBC methods is verified by experimental results.