An Improved African Vulture Optimization for Biding Strategy of Two-Settlement Market in China

Cao Wei,Chen Xiao,Cao Zhiwei,Badami Benjamin 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.2

The present study introduces a new optimal bidding strategy (BS) in the Two-settlement market for a case study in China. Here, an enhanced design of the African Vulture Optimizer (AVO) is utilized for optimizing the process based on the market-clearing price probability function. Subtractive clustering is also used for the similarity measures clustering between the present day and the later day. Non-decreasing bidding curves and a cap price bordered about 70 $/MWh has been considered for the production part of the day-ahead market competition. Also, the hourly maximum power of the generation company and hourly market clearing price are considered for providing a suitable examination of the model in the dataset. The optimal bidding strategy in this study is used to testify on bidding data from China from 2010 to 2019. Simulation results show that the average return in the company of generation in the sets raise to 25.84% and 13.83% compared with Model 1 as a simple model and Model 2 with a Q-Learning model, respectively which is for China's real electricity market.

Targeting the IL-1β/IL-1Ra pathways for the aggregation of human islet amyloid polypeptide in an ex vivo organ culture system of the intervertebral disc

Cao Yang,Xinghuo Wu,Zhiwei Liao,Kun Wang,Wenbin Hua,Xianzhe Liu,Yu Song,Yukun Zhang,Shuhua Yang 생화학분자생물학회 2019 Experimental and molecular medicine Vol.51 No.-

Intervertebral disc degeneration (IDD) is characterized by excessive apoptosis of nucleus pulposus (NP) cells and hyperactive extracellular matrix (ECM) catabolism. Our previous studies revealed the relationship between human islet amyloid polypeptide (hIAPP) and NP cell apoptosis. However, the role of hIAPP aggregates in IDD has not yet been investigated. This study aimed to determine whether the accumulation of hIAPP aggregates promotes IDD progression. The aggregation of hIAPP increased in human NP tissues during IDD. The deposition of hIAPP aggravated the compression-induced IDD that promoted NP cell apoptosis and ECM degradation via IL-1β/IL-1Ra signaling in an ex vivo rat disc model. Moreover, neutralizing IL-1β augmented the protective effects of hIAPP overexpression by decreasing hIAPP aggregation in human NP cells. These results suggest that the aggregation of hIAPP promotes NP cell apoptosis and ECM degradation ex vivo and in vitro by disrupting the balance of IL-1β/IL-1Ra signaling.

Observer-based Adaptive Robust Control of Soft Pneumatic Network Actuators

Guizhou Cao,Yanhong Liu,Zhiwei Zhu 제어·로봇·시스템학회 2022 International Journal of Control, Automation, and Vol.20 No.5

Fabricated by elastomer materials, soft pneumatic network actuators (PNAs) not only enable versatile applications but also bring challenges to the high-performance control. This study presents new observer-based adaptive robust controllers for PNAs subjected to system uncertainties and unavailable states. First, a sliding patchbased observer and an observer-based controller are addressed for PNAs with known upper bounds, and stability of closed-looped systems is proved by the Lyapunov method. Second, a novel disturbance observer is proposed for the case of prior unknown bounds of uncertainties, and the stability of the closed-looped system controlled by an adaptive robust controller is also analyzed by the Lyapunov method. Finally, the effectiveness of the proposed controllers is verified by simulations and experiments.

Frequency Stabilization Method for Grid Integration of Large-scale Centralized Wind Farms via VSC-HVDC Technology

Peng, Yanjian,Li, Yong,Liu, Fang,Xu, Zhiwei,Cao, Yijia The Korean Institute of Power Electronics 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.2

This work proposes a control method of frequency stabilization for grid integration of large-scale wind farms via the voltage source converter-based high-voltage direct current (VSC-HVDC) technology. First, the topology of grid integration of a large-scale wind farm via the VSC-HVDC link is provided, and simple control strategies for wind turbines, wind farm side VSC (WFVSC), and grid side VSC are presented. Second, a mathematical model between the phase angle of WFVSC and the frequency of the wind farm is established. The control principle of the large-scale wind power integrated system is analyzed in theory in accordance with the mathematical model. Third, frequency and AC voltage controllers of WFVSC are designed based on the mathematical model of the relationships between the phase angle of WFVSC and the frequency of the wind farm, and between the modulation index of WFVSC and the voltage of the wind farm. Corresponding controller structures are established by deriving a transfer function, and an optimization method for selecting the parameters of the frequency controller is presented. Finally, a case study is performed under different operating conditions by using the DIgSILENT/PowerFactory software. Results show that the proposed control method has good performance in the frequency stabilization of the large-scale wind power integrated system via the VSC-HVDC technology.

Frequency Stabilization Method for Grid Integration of Large-scale Centralized Wind Farms via VSC-HVDC Technology

Yanjian Peng,Yong Li,Fang Liu,Zhiwei Xu,Yijia Cao 전력전자학회 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.2

This work proposes a control method of frequency stabilization for grid integration of large-scale wind farms via the voltage source converter-based high-voltage direct current (VSC-HVDC) technology. First, the topology of grid integration of a large-scale wind farm via the VSC-HVDC link is provided, and simple control strategies for wind turbines, wind farm side VSC (WFVSC), and grid side VSC are presented. Second, a mathematical model between the phase angle of WFVSC and the frequency of the wind farm is established. The control principle of the large-scale wind power integrated system is analyzed in theory in accordance with the mathematical model. Third, frequency and AC voltage controllers of WFVSC are designed based on the mathematical model of the relationships between the phase angle of WFVSC and the frequency of the wind farm, and between the modulation index of WFVSC and the voltage of the wind farm. Corresponding controller structures are established by deriving a transfer function, and an optimization method for selecting the parameters of the frequency controller is presented. Finally, a case study is performed under different operating conditions by using the DIgSILENT/PowerFactory software. Results show that the proposed control method has good performance in the frequency stabilization of the large-scale wind power integrated system via the VSC-HVDC technology.

Feasibility of Two-Screw Anterior Fixation for Odontoid Fractures in a Chinese Population: A Morphometric Study Based on Computed Tomography

Yixiang Ai,Dereje Gobena Alemayehu,Genwen Mao,Yaping Liang,Ran Cao,Jiale Hu,Yimin Yang,Zhiwei Ren 대한정형외과학회 2023 Clinics in Orthopedic Surgery Vol.15 No.6

Background: To evaluate the feasibility of treating odontoid fractures in the Chinese population with two cortical screws based on computed tomography (CT) scans and describe a new measurement strategy to guide screw insertion in treating these fractures. Methods: A retrospective review of cervical computed tomographic scans of 128 patients (aged 18–76 years; men, 55 [43.0%]) was performed. The minimum external transverse diameter (METD), minimum external anteroposterior diameter (MEAD), maximum screw length (MSL), and screw projection back angle (SPBA) of the odontoid process were measured on coronal and sagittal CT images. Results: The mean values of METD and MEAD were 10.0 ± 1.1 mm and 12.0 ± 1.0 mm, respectively, in men and 9.2 ± 1.0 mm and 11.0 ± 1.0 mm, respectively, in women. Both measurements were significantly higher in men (p < 0.001). In total, 87 individuals (68%) had METD > 9.0 mm that could accommodate two 3.5-mm cortical screws. The mean MSL value and SPBA range were 34.4 ± 2.9 mm and 13.5°–24.2°, respectively, with no statistically significant difference between men and women. Conclusions: The insertion of two 3.5-mm cortical screws was possible for anterior fixation of odontoid fractures in 87 patients (68%) in our study, and there was a statistically significant difference between men and women.

Engineering “cell-particle hybrids” of pancreatic islets and bioadhesive FK506-loaded polymeric microspheres for local immunomodulation in xenogeneic islet transplantation

Nguyen, Tiep Tien,Pham, Tung Thanh,Nguyen, Hanh Thuy,Nepal, Mahesh Raj,Phung, Cao Dai,You, Zhiwei,Katila, Nikita,Pun, Nirmala Tillija,Jeong, Tae Cheon,Choi, Dong-Young,Park, Pil-Hoon,Yong, Chul Soon,K Elsevier 2019 Biomaterials Vol.221 No.-

<P><B>Abstract</B></P> <P>Host immune response remains an obstacle in cell-replacement therapy for treating type I diabetes. Long-term systemic immunosuppression results in suboptimal efficacy and adverse reactions. Thus, “cell-particle hybrids” of pancreatic islets and tissue-adhesive, polydopamine-coated, FK506-loaded biodegradable microspheres (PD-FK506-MS) were developed to locally modulate the immune response at the transplantation site. Coating of FK506-MS with PD enabled the rapid formation of stable cell-particle hybrids without significant changes in islet viability and functionality. Extremely low quantities of FK506 (approximately 600 ng per recipient) sustainably released from cell-particle hybrids effectively prolonged survival of xenogeneic islet graft. Interestingly, FK506 exhibited extended bioavailability in the grafts but was undetectable in systemic circulation and other tissues. Moreover, mRNA expression of inflammatory cytokines was significantly inhibited in the PD-FK506-MS-containing grafts but not in lymphoid organs. This study presents a promising platform that facilitates the translation of local immunomodulation towards an effective strategy with improved safety profiles for treating type I diabetes.</P>

Cytosolic escape of mitochondrial DNA triggers cGAS-STING-NLRP3 axis-dependent nucleus pulposus cell pyroptosis

Zhang Weifeng,Li Gaocai,Luo Rongjin,Lei Jie,Song Yu,Wang Bingjin,Ma Liang,Liao Zhiwei,Ke Wencan,Liu Hui,Hua Wenbin,Zhao Kangcheng,Feng Xiaobo,Wu Xinghuo,Zhang Yukun,Wang Kun,Yang Cao 생화학분자생물학회 2022 Experimental and molecular medicine Vol.54 No.-

Low back pain (LBP) is a major musculoskeletal disorder and the socioeconomic problem with a high prevalence that mainly involves intervertebral disc (IVD) degeneration, characterized by progressive nucleus pulposus (NP) cell death and the development of an inflammatory microenvironment in NP tissue. Excessively accumulated cytosolic DNA acts as a damage-associated molecular pattern (DAMP) that is monitored by the cGAS-STING axis to trigger the immune response in many degenerative diseases. NLRP3 inflammasome-dependent pyroptosis is a type of inflammatory programmed death that promotes a chronic inflammatory response and tissue degeneration. However, the relationship between the cGAS-STING axis and NLRP3 inflammasome-induced pyroptosis in the pathogenesis of IVD degeneration remains unclear. Here, we used magnetic resonance imaging (MRI) and histopathology to demonstrate that cGAS, STING, and NLRP3 are associated with the degree of IVD degeneration. Oxidative stress induced cGAS-STING axis activation and NLRP3 inflammasome-mediated pyroptosis in a STING-dependent manner in human NP cells. Interestingly, the canonical morphological and functional characteristics of mitochondrial permeability transition pore (mPTP) opening with the cytosolic escape of mitochondrial DNA (mtDNA) were observed in human NP cells under oxidative stress. Furthermore, the administration of a specific pharmacological inhibitor of mPTP and self-mtDNA cytosolic leakage effectively reduced NLRP3 inflammasome-mediated pyroptotic NP cell death and microenvironmental inflammation in vitro and degenerative progression in a rat disc needle puncture model. Collectively, these data highlight the critical roles of the cGAS-STING-NLRP3 axis and pyroptosis in the progression of IVD degeneration and provide promising therapeutic approaches for discogenic LBP.

O-GlcNAc transferase regulates intervertebral disc degeneration by targeting FAM134B-mediated ER-phagy

Luo Rongjin,Li Gaocai,Zhang Weifei,Liang Huaizhen,Lu Saideng,Cheung Jason Pui Yin,Zhang Teng,Tu Ji,Liu Hui,Liao Zhiwei,Ke Wencan,Wang Bingjin,Song Yu,Yang Cao 생화학분자생물학회 2022 Experimental and molecular medicine Vol.54 No.-

Both O-linked β-N-acetylglucosaminylation (O-GlcNAcylation) and endoplasmic reticulum-phagy (ER-phagy) are well-characterized conserved adaptive regulatory mechanisms that maintain cellular homeostasis and function in response to various stress conditions. Abnormalities in O-GlcNAcylation and ER-phagy have been documented in a wide variety of human pathologies. However, whether O-GlcNAcylation or ER-phagy is involved in the pathogenesis of intervertebral disc degeneration (IDD) is largely unknown. In this study, we investigated the function of O-GlcNAcylation and ER-phagy and the related underlying mechanisms in IDD. We found that the expression profiles of O-GlcNAcylation and O-GlcNAc transferase (OGT) were notably increased in degenerated NP tissues and nutrient-deprived nucleus pulposus (NP) cells. By modulating the O-GlcNAc level through genetic manipulation and specific pharmacological intervention, we revealed that increasing O-GlcNAcylation abundance substantially enhanced cell function and facilitated cell survival under nutrient deprivation (ND) conditions. Moreover, FAM134B-mediated ER-phagy activation was regulated by O-GlcNAcylation, and suppression of ER-phagy by FAM134B knockdown considerably counteracted the protective effects of amplified O-GlcNAcylation. Mechanistically, FAM134B was determined to be a potential target of OGT, and O-GlcNAcylation of FAM134B notably reduced FAM134B ubiquitination-mediated degradation. Correspondingly, the protection conferred by modulating O-GlcNAcylation homeostasis was verified in a rat IDD model. Our data demonstrated that OGT directly associates with and stabilizes FAM134B and subsequently enhances FAM134B-mediated ER-phagy to enhance the adaptive capability of cells in response to nutrient deficiency. These findings may provide a new option for O-GlcNAcylation-based therapeutics in IDD prevention.