Earthquake loss assessment framework of ductile RC frame using component- performance -based methodology

Shengfang Qiao,Xiaolei Han,Hesong Hu,Mengxiong Tang 국제구조공학회 2024 Structural Engineering and Mechanics, An Int'l Jou Vol.91 No.4

The earthquake loss assessment framework of ductile reinforced concrete (or RC) frame using componentperformance -based methodology was studied in this paper. The elasto-plastic rotation angle was used as the damage indicator of structural component, and the damage-to-loss model was proposed on the basis of the deformation indicator of structural component. Dynamic instability during incremental dynamic analysis was taken as collapse criterion, and column failure was taken as criterion that structure has to be demolished. Expected earthquake losses of low-rise, mid-rise and high-rise RC frames were discussed. The expected earthquake loss encompassed collapse loss, demolition loss and repair loss. Furthermore, component groups of RC frame were divided into structural components, nonstructural components and rugged components. The results indicate that ductile RC frame is more likely to be demolished than collapse, especially in low-rise and mid-rise RC frames. Furthermore, the less collapse margin ratio the structure has, the more demolition probability the structure will suffer under rare earthquake. The demolition share of total earthquake loss might be more prominent than repair share and collapse share in ductile RC frame.

On the Disturbance Rejection Control of Flexible-joint Robot: A GPIO-based Approach

Huiming Wang,Yang Zhang,Xiaolei Chen,Xianlun Tang,I-Ming Chen 제어·로봇·시스템학회 2021 International Journal of Control, Automation, and Vol.19 No.8

A robust disturbance rejection control scheme is addressed for the trajectory tracking problem of a flexible-joint robot (FJR). The system is always severely affected by various types of unknown disturbances including model errors, couplings, changing working environments as well as unmodeled dynamics. These disturbances on the link and actuator side will deteriorate the control performance of FJR. By considering all the disturbances as an unknown lumped time-varying disturbance, a flatness description of FJR is developed. Then, a new output feedback controller is constructed through the estimates of unmeasurable states and unknown lumped disturbance provided by a generalized proportional integral observer (GPIO). The stability of the closed-loop system with the driven of the proposed control scheme is guaranteed under some mild assumptions. Compared with the conventional linear active disturbance rejection control (LADRC) scheme, test results are presented to demonstrate the feasibility and efficacy of the proposed control approach.

A study of a new hybrid vibration energy harvester based on broadband-multimode

Bing Chen,Shiqing Li,Xiaolei Tang,Lijie Zhang 국제구조공학회 2021 Smart Structures and Systems, An International Jou Vol.28 No.1

To improve the energy conversion efficiency and working frequency bandwidth of a single frequency piezoelectric vibration energy harvester, a new type of hybrid vibration energy harvester is developed which is combined with the mechanism of piezoelectric and electromagnetic energy conversion. The system comprises of a PZT cantilever beam, an elastic suspended magnetic mass, a magnet block attached to the end of the cantilever beam and a resonator. The addition of resonator can not only increase the mode, but also adjust the frequency of harvester flexibly. Nonlinear magnetic force of magnet block not only broadens the frequency band and improves the output performance of the system, but also changes the resonant frequency to make the harvester have better adjustable performance. On this basis, an improved electromechanical coupled analytical model of continuum is proposed which can be solved by the Runge-Kutta algorithm and the influence of different factors (the mass and spring stiffness of the resonator, as well as the electromechanical coupling coefficient, electromagnetic coupling coefficient, magnet mass and magnetic flux) on the output are analyzed. According to the prototype of the vibration energy harvester developed, an experimental system was built. The performance of the independent and hybrid energy harvesters is evaluated by experimental and analytical methods. The peak output voltage of the piezoelectric part was about 4 times that of the electromagnetic part. The peak output current of the electromagnetic part is about 30 times that of the piezoelectric part. The study results show that the proposed new hybrid vibration energy harvester can achieve a wider frequency range and multimodal vibration energy harvesting. In addition, the bandwidth and power of the harvester can be dynamically adjusted by changing the resonator or electromechanical coupling coefficient, and the bandwidth of the harvester can also be adjusted by changing the quality and characteristics of the magnet.

Melatonin protects endothelial progenitor L255cells against AGE-induced apoptosis via autophagy flux stimulation and promotes wound healing in diabetic mice

Haiming Jin,Zengjie Zhang,Chengui Wang,Qian Tang,Jianle Wang,Xueqin Bai,Qingqing Wang,Majid Nisar,Naifeng Tian,Quan Wang,Cong Mao,Xiaolei Zhang,Xiangyang Wang 생화학분자생물학회 2018 Experimental and molecular medicine Vol.50 No.-

Wound healing is delayed in diabetic patients. Increased apoptosis and endothelial progenitor cell (EPC) dysfunction are implicated in delayed diabetic wound healing. Melatonin, a major secretory product of the pineal gland, promotes diabetic wound healing; however, its mechanism of action remains unclear. Here, EPCs were isolated from the bone marrow of mice. Treatment of EPCs with melatonin alleviated advanced glycation end product (AGE)-induced apoptosis and cellular dysfunction. We further examined autophagy flux after melatonin treatment and found increased light chain 3 (LC3) and p62 protein levels in AGE-treated EPCs. However, lysosome-associated membrane protein 2 expression was decreased, indicating that autophagy flux was impaired in EPCs treated with AGEs. We then evaluated autophagy flux after melatonin treatment and found that melatonin increased the LC3 levels, but attenuated the accumulation of p62, suggesting a stimulatory effect of melatonin on autophagy flux. Blockage of autophagy flux by chloroquine partially abolished the protective effects of melatonin, indicating that autophagy flux is involved in the protective effects of melatonin. Furthermore, we found that the AMPK/mTOR signaling pathway is involved in autophagy flux stimulation by melatonin. An in vivo study also illustrated that melatonin treatment ameliorated impaired wound healing in a streptozotocin-induced diabetic wound healing model. Thus, our study shows that melatonin protects EPCs against apoptosis and dysfunction via autophagy flux stimulation and ameliorates impaired wound healing in vivo, providing insight into its mechanism of action in diabetic wound healing.

Major ginsenosides from Panax ginseng promote aerobic cellular respiration and SIRT1-mediated mitochondrial biosynthesis in cardiomyocytes and neurons

Huang, Qingxia,Lou, Tingting,Lu, Jing,Wang, Manying,Chen, Xuenan,Xue, Linyuan,Tang, Xiaolei,Qi, Wenxiu,Zhang, Zepeng,Su, Hang,Jin, Wenqi,Jing, Chenxu,Zhao, Daqing,Sun, Liwei,Li, Xiangyan The Korean Society of Ginseng 2022 Journal of Ginseng Research Vol.46 No.6

Background: Aerobic cellular respiration provides chemical energy, adenosine triphosphate (ATP), to maintain multiple cellular functions. Sirtuin 1 (SIRT1) can deacetylate peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α) to promote mitochondrial biosynthesis. Targeting energy metabolism is a potential strategy for the prevention and treatment of various diseases, such as cardiac and neurological disorders. Ginsenosides, one of the major bioactive constituents of Panax ginseng, have been extensively used due to their diverse beneficial effects on healthy subjects and patients with different diseases. However, the underlying molecular mechanisms of total ginsenosides (GS) on energy metabolism remain unclear. Methods: In this study, oxygen consumption rate, ATP production, mitochondrial biosynthesis, glucose metabolism, and SIRT1-PGC-1α pathways in untreated and GS-treated different cells, fly, and mouse models were investigated. Results: GS pretreatment enhanced mitochondrial respiration capacity and ATP production in aerobic respiration-dominated cardiomyocytes and neurons, and promoted tricarboxylic acid metabolism in cardiomyocytes. Moreover, GS clearly enhanced NAD⁺-dependent SIRT1 activation to increase mitochondrial biosynthesis in cardiomyocytes and neurons, which was completely abrogated by nicotinamide. Importantly, ginsenoside monomers, such as Rg1, Re, Rf, Rb1, Rc, Rh1, Rb2, and Rb3, were found to activate SIRT1 and promote energy metabolism. Conclusion: This study may provide new insights into the extensive application of ginseng for cardiac and neurological protection in healthy subjects and patients.

Nitro-oleic Acid Decreases Transcription of the Angiotensin II Type I Receptor Gene in Aortic Smooth Muscle Cells

Huan Wang,Hongsheng Ouyang,Yaping Tian,Zhuang Liu,Xiaolei Han,Xingxing Liu,Guangyao Ran,Gangqi Wang,Daxin Pang,Xiaochun Tang 한국생물공학회 2014 Biotechnology and Bioprocess Engineering Vol.19 No.4

Nitroalkene derivatives of nitro-oleic acid(OA-NO2) regulate pluripotent cell signaling in vivo underphysiological and pathological conditions. Angiotensin IItype 1 receptor (AT1R) plays an important role in thecardiovascular system. In this study, OA-NO2 reduced theAT1R mRNA level, specifically in primary smooth musclecells, showing a 70% reduction in rat smooth muscle cells(RASMCs) and a 50% reduction in pig smooth musclecells (PASMCs). These effects were not observed in CHOcells, which highly express AT1R. The AT1R mRNA decayrate was unchanged after OA-NO2 compared with OAtreatment. Nitric oxide (NO) and peroxisome proliferatoractivatedreceptor gamma (PPARγ) did not alter thereduced effects of OA-NO2 on the AT1R mRNA level inSMCs. However, Sp1-mediated activation of the AT1Rpromoter was reduced in response to OA-NO2 in RASMCsbut not 293T cells. In addition, the nuclear factor-kappa B(NF-κB) pathway was involved in the OA-NO2-mediateddownregulation of AT1R transcription in SMCs. Takentogether, our results demonstrate that OA-NO2 specificallyinhibits AT1R mRNA expression in primary smooth musclecells via the NF-κB pathway.