LncRNA A2M-AS1 lessens the injury of cardiomyocytes caused by hypoxia and reoxygenation via regulating IL1R2

Xue‑Lian Song,Fei‑Fei Zhang,Wen‑Jing Wang,Xin‑Ning Li,Yi Dang,Ying‑Xiao Li,Qian Yang,Mei‑Jing Shi,Xiao‑Yong Qi 한국유전학회 2020 Genes & Genomics Vol.42 No.12

Background: Myocardial ischemia and reperfusion injury (MI/RI) is a complex pathophysiological process, which can lead to severe myocardial injury. The long noncoding RNA alpha-2-macroglobulin antisense RNA 1 (A2M-AS1) has been revealed to be abnormally expressed in MI, However, its function in MI and the potential mechanism are still unclear. Objective: To evaluate the functional role of A2M-AS1 in hypoxia/reoxygenation (H/R)-induced neonatal cardiomyocytes and its potential molecular mechanism. Methods: Dataset GSE66360 was obtained from GEO database for analyzing the RNA expression of A2M-AS1 and interleukin 1 receptor type 2 (IL1R2). KEGG pathway enrichment analysis of the genes that co-expressed with A2M-AS1 was performed. Human neonatal cardiomyocytes were subjected to H/R to construct in vitro models. QRT-PCR and Western blot were adopted to test the levels of mRNA and protein. The viability and apoptosis of cardiomyocytes were tested by CCK-8 and flow cytometry assays, respectively. Results: The expression of A2M-AS1 was notably downregulated in H/R-treated cardiomyocytes. Overexpression of A2M-AS1 can notably enhance the cell viability of H/R-damaged cardiomyocytes, whereas knockdown of A2M-AS1 showed the opposite outcomes. Besides, a negative correlation was showed between A2M-AS1 and IL1R2 expression. In H/R-treated cardiomyocytes, overexpression of IL1R2 weakened the promoting proliferation and anti-apoptosis effects caused by overexpressing A2M-AS1, however, IL1R2-knockdown abolished the anti-proliferation and pro-apoptosis effects caused by silencing A2M-AS1. Conclusion: This study demonstrates the potential regulatory role of A2M-AS1/ IL1R2 axis in cardiomyocytes suffered from H/R, and provides insight into the protection of MI/RI.

A Quantitative Evaluation and Comparison of Harmonic Elimination Algorithms Based on Moving Average Filter and Delayed Signal Cancellation in Phase Synchronization Applications

Liansong Xiong,Fang Zhuo,Feng Wang,Xiaokang Liu,Minghua Zhu,Hao Yi 전력전자학회 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.2

The harmonic components of grid voltage result in oscillations of the calculated phase obtained via phase synchronization. This affects the security and stability of grid-connected converters. Moving average filter, delayed signal cancellation and their related harmonic elimination algorithms are major methods for such issues. However, all of the existing methods have their limitations in dealing with multiple harmonics issues. Furthermore, few studies have focused on a comparison and evaluation of these algorithms to achieve optimal algorithm selections in specific applications. In this paper, these algorithms are quantitatively analyzed based on the derived mathematical models. Moreover, an enhanced moving average filter and enhanced delayed signal cancellation algorithms, which are applicable for eliminating a group of selective harmonics with only one calculation block, are proposed. On this basis, both a comprehensive comparison and a quantitative evaluation of all of the aforementioned algorithms are made from several aspects, including response speed, required data storage size, sensitivity to sampling frequency, and elimination of random noise and harmonics. With the conclusions derived in this paper, better overall performance in terms of harmonic elimination can be achieved. In addition, experimental results under different conditions demonstrate the validity of this study.

A Novel Fast Open-loop Phase Locking Scheme Based on Synchronous Reference Frame for Three-phase Non-ideal Power Grids

Liansong Xiong,Fang Zhuo,Feng Wang,Xiaokang Liu,Minghua Zhu,Hao Yi 전력전자학회 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.4

Rapid and accurate phase synchronization is critical for the reliable control of grid-tied inverters. However, the commonly used software phase-locked loop methods do not always satisfy the need for high-speed and accurate phase synchronization under severe grid imbalance conditions. To address this problem, this study develops a novel open-loop phase locking scheme based on a synchronous reference frame. The proposed scheme is characterized by remarkable response speed, high accuracy, and easy implementation. It comprises three functional cascaded blocks: fast orthogonal signal generation block, fast fundamental-frequency positive sequence component construction block, and fast phase calculation block. The developed virtual orthogonal signal generation method in the first block, which is characterized by noise immunity and high accuracy, can effectively avoid approximation errors and noise amplification in a wide range of sampling frequencies. In the second block, which is the foundation for achieving fast phase synchronization within 3 ms, the fundamental-frequency positive sequence components of unsymmetrical grid voltages can be achieved with the developed orthogonal signal construction strategy and the symmetrical component method. The real-time grid phase can be consequently obtained in the third block, which is free from self-tuning closed-loop control and thus improves the dynamic performance of the proposed scheme. The proposed scheme is adaptive to severe unsymmetrical grid voltages with sudden changes in magnitude, phase, and/or frequency. Moreover, this scheme is able to eliminate phase errors induced by harmonics and random noise. The validity and utility of the proposed scheme are verified by the experimental results.

A Quantitative Evaluation and Comparison of Harmonic Elimination Algorithms Based on Moving Average Filter and Delayed Signal Cancellation in Phase Synchronization Applications

Xiong, Liansong,Zhuo, Fang,Wang, Feng,Liu, Xiaokang,Zhu, Minghua,Yi, Hao The Korean Institute of Power Electronics 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.2

The harmonic components of grid voltage result in oscillations of the calculated phase obtained via phase synchronization. This affects the security and stability of grid-connected converters. Moving average filter, delayed signal cancellation and their related harmonic elimination algorithms are major methods for such issues. However, all of the existing methods have their limitations in dealing with multiple harmonics issues. Furthermore, few studies have focused on a comparison and evaluation of these algorithms to achieve optimal algorithm selections in specific applications. In this paper, these algorithms are quantitatively analyzed based on the derived mathematical models. Moreover, an enhanced moving average filter and enhanced delayed signal cancellation algorithms, which are applicable for eliminating a group of selective harmonics with only one calculation block, are proposed. On this basis, both a comprehensive comparison and a quantitative evaluation of all of the aforementioned algorithms are made from several aspects, including response speed, required data storage size, sensitivity to sampling frequency, and elimination of random noise and harmonics. With the conclusions derived in this paper, better overall performance in terms of harmonic elimination can be achieved. In addition, experimental results under different conditions demonstrate the validity of this study.

A Novel Fast Open-loop Phase Locking Scheme Based on Synchronous Reference Frame for Three-phase Non-ideal Power Grids

Xiong, Liansong,Zhuo, Fang,Wang, Feng,Liu, Xiaokang,Zhu, Minghua,Yi, Hao The Korean Institute of Power Electronics 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.4

Rapid and accurate phase synchronization is critical for the reliable control of grid-tied inverters. However, the commonly used software phase-locked loop methods do not always satisfy the need for high-speed and accurate phase synchronization under severe grid imbalance conditions. To address this problem, this study develops a novel open-loop phase locking scheme based on a synchronous reference frame. The proposed scheme is characterized by remarkable response speed, high accuracy, and easy implementation. It comprises three functional cascaded blocks: fast orthogonal signal generation block, fast fundamental-frequency positive sequence component construction block, and fast phase calculation block. The developed virtual orthogonal signal generation method in the first block, which is characterized by noise immunity and high accuracy, can effectively avoid approximation errors and noise amplification in a wide range of sampling frequencies. In the second block, which is the foundation for achieving fast phase synchronization within 3 ms, the fundamental-frequency positive sequence components of unsymmetrical grid voltages can be achieved with the developed orthogonal signal construction strategy and the symmetrical component method. The real-time grid phase can be consequently obtained in the third block, which is free from self-tuning closed-loop control and thus improves the dynamic performance of the proposed scheme. The proposed scheme is adaptive to severe unsymmetrical grid voltages with sudden changes in magnitude, phase, and/or frequency. Moreover, this scheme is able to eliminate phase errors induced by harmonics and random noise. The validity and utility of the proposed scheme are verified by the experimental results.

A Fast and Accurate Detection Method of Instantaneous Reactive Current in Single-phase Power System

Xiaokang Liu,Liansong Xiong,Fang Zhuo,Ying Chen,Minghua Zhu 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

Fast and accurate detection of instantaneous reactive current in single-phase power system is a pre-requisite for the precise control of STATCOM (Static Synchronous Compensator). A major solution is based on the construction of virtual orthogonal signal in rotational coordinate transformation; however, conventional methods show weaknesses in the speed of detection and the ability of noise and harmonic suppression. In this paper, a novel method of instantaneous reactive current detection in single-phase system, with fast and accurate property as well as harmonic and noise susceptibility, is proposed. Firstly, a novel virtual orthogonal signal generation algorithm is deduced, remarkably improving the immediacy and precision of detection in synchronous reference frame. Then an enhanced moving average filter (EMAF) is utilized in cascade and its design principle is proposed, sufficiently eliminating the effects of noise and harmonics. Finally, experiments reveal that the proposed detection scheme can achieve the satisfactory control goals.

Theoretical and experimental investigation of the pressure ratio distribution and the regulation strategy of a two-stage turbocharging system for various altitudes operation

Huiyan Zhang,Xuyang Tang,Liansong Mu,Lei Shi,Kangyao Deng 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.3

Fixed two-stage turbocharging system matched at high altitude leads to engine performance deterioration at low altitudes due to unreasonable pressure ratio distribution between two stages. In this paper, a thermodynamic model of regulated two-stage turbocharging system is established. Theoretical analysis shows the pressure ratio distribution should lean towards a turbocharger with greater efficiency, and the high-altitude operation intensifies the role of HP stage. Experiments are conducted on an environment simulation test bench. Then, the optimal pressure ratio distribution and ETAR at various altitudes are proposed. Experiment results demonstrate that the turbocharging system boosts sufficient intake air with the optimal ETAR. Compared to that with the fixed turbocharging system, the maximum increment of the overall efficiency is 9.3 % at 0 m and attains 1.5 % at 3000 m. Consequently, the output torque is 100 % recovered below 3000 m, and it exceeds 91 % at 4500 m. Moreover, the optimal ETAR reduces the BSFC under low altitude conditions.