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.

Oxidative stress-induced circKIF18A downregulation impairs MCM7-mediated anti-senescence in intervertebral disc degeneration

Wang Jianle,Xia Dongdong,Lin Yan,Xu Wenbin,Wu Yaosen,Chen Jiaoxiang,Chu Junjie,Shen Panyang,Weng Sheji,Wang Xiangyang,Shen Lifeng,Fan Shunwu,Shen Shuying 생화학분자생물학회 2022 Experimental and molecular medicine Vol.54 No.-

Low back pain, triggered by intervertebral disc degeneration (IVDD), is one of the most common causes of disability and financial expenditure worldwide. However, except for surgical interventions, effective medical treatment to prevent the progression of IVDD is lacking. This study aimed to investigate the effects of circKIF18A, a novel circRNA, on IVDD progression and to explore its underlying mechanism in IVDD. In this study, we found that oxidative stress was positively correlated with nucleus pulposus cell (NPC) senescence in IVDD and that circKIF18A was downregulated in IVDD and attenuated senescent phenotypes such as cell cycle arrest and extracellular matrix degradation in NPCs. Mechanistically, circKIF18A competitively suppressed ubiquitin-mediated proteasomal degradation of MCM7, and the protective effects of circKIF18A on NPCs were partially mediated by MCM7 under oxidative stress. Intradiscal injection of adenoviral circKIF18A ameliorated IVDD in a rat model. This study revealed that circKIF18A regulates NPC degeneration by stabilizing MCM7 and identified a novel signaling pathway, the circKIF18A-MCM7 axis, for anti-senescence molecular therapy in IVDD.

Neuroprotective potential of imatinib in global ischemiareperfusion- induced cerebral injury: possible role of Janus-activated kinase 2/signal transducer and activator of transcription 3 and connexin 43

Jieying Wang,Taomin Bai,Nana Wang,Hongyan Li,Xiangyang Guo 대한생리학회-대한약리학회 2020 The Korean Journal of Physiology & Pharmacology Vol.24 No.1

The present study was aimed to explore the neuroprotective role of imatinib in global ischemia-reperfusion-induced cerebral injury along with possible mechanisms. Global ischemia was induced in mice by bilateral carotid artery occlusion for 20 min, which was followed by reperfusion for 24 h by restoring the blood flow to the brain. The extent of cerebral injury was assessed after 24 h of global ischemia by measuring the locomotor activity (actophotometer test), motor coordination (inclined beam walking test), neurological severity score, learning and memory (object recognition test) and cerebral infarction (triphenyl tetrazolium chloride stain). Ischemia-reperfusion injury produced significant cerebral infarction, impaired the behavioral parameters and decreased the expression of connexin 43 and phosphorylated signal transducer and activator of transcription 3 (p-STAT3) in the brain. A single dose administration of imatinib (20 and 40 mg/kg) attenuated ischemia-reperfusioninduced behavioral deficits and the extent of cerebral infarction along with the restoration of connexin 43 and p-STAT3 levels. However, administration of AG490, a selective Janus-activated kinase 2 (JAK2)/STAT3 inhibitor, abolished the neuroprotective actions of imatinib and decreased the expression of connexin 43 and p-STAT3. It is concluded that imatinib has the potential of attenuating global ischemia-reperfusion- induced cerebral injury, which may be possibly attributed to activation of JAK2/ STAT3 signaling pathway along with the increase in the expression of connexin 43.

Device-to-Device Relay Cooperative Transmission Based on Network Coding

( Jing Wang ),( Mingsheng Ouyang ),( Wei Liang ),( Jun Hou ),( Xiangyang Liu ) 한국인터넷정보학회 2017 KSII Transactions on Internet and Information Syst Vol.11 No.7

Due to the advantages of low transmit power consumption, high spectral efficiency and extended system coverage, Device-to-Device (D2D) communication has drawn explosive attention in wireless communication field. Considering that intra-cell interference caused between cellular signals and D2D signals, in this paper, a network coding-based D2D relay cooperative transmission algorithm is proposed. Under D2D single-hop relay transmission mode, cellular interfering signals can be regarded as useful signals to code with D2D signals at D2D relay node. Using cellular interfering signals and network coded signals, D2D receiver restores the D2D signals to achieve the effect of interference suppression. Theoretical analysis shows that, compared with Amplify-and-forward (AF) mode and Decode-and-forward (DF) mode, the proposed algorithm can dramatically increase the link achievable rate. Furthermore, simulation experiment verifies that by employing the proposed algorithm, the interference signals in D2D communication can be eliminated effectively, and meanwhile the symbol error rate (SER) performance can be improved.

Resonance Analysis of Medium Voltage Multi-Microgrids Considering the Interaction of Controllable Series Compensator and Grid-Connected Inverters

Yang Weiman,Wang Dongming,Wang Xinggui,Li Xiangyang,Zhang Peng 대한전기학회 2024 Journal of Electrical Engineering & Technology Vol.19 No.2

The interaction of a controlled series compensator (CSC) with other power electronics and basic power components in a multi-microgrid (MMG) maybe lead to complex resonance problems. In this paper, the frequency domain analysis method and the mode analysis method are combined to analyze the resonance characteristics of the medium-voltage microgrid cluster system under the action of two controllable series compensators, transformer-coupled series compensator (TCSC) and capacitive-coupled series compensator (CCSC). Firstly, based on the equivalent output impedance models of TCSC and CCSC, the equivalent output impedance characteristics of TCSC and CCSC are explored by frequency domain analysis. Secondly, combined with the impedance network model of cluster system, the resonance characteristics of the MMG after separate and together access to these two controllable series compensators at diferent locations are explored by modal analysis method. The results show that the equivalent output impedance of the two couple-type compensators in a certain frequency band is capacitive, and CCSC has a wider capacitive frequency band. Changes in controller parameter selection can afect band range and capacitance degree. The CSC control parameters afect the system resonance frequency and resonance center, and when the grid-connected inverter circuit parameters are diferent, the mode of system resonance will also change. The combination of frequency domain analysis and modal analysis is an efective means to study the resonance stability of microgrid cluster systems.

Current boundary‑based predictive current control of induction machines with lower switching frequencies

Xin Qi,Chenyu Wang,Boxuan Tian,Mario Pacas,Xiangyang Shi,Aibin Jia 전력전자학회 2024 JOURNAL OF POWER ELECTRONICS Vol.24 No.2

An excessively high switching frequency causes significant losses in inverters, especially in high-power applications, which should be avoided. Predictive control, based on a circular boundary restriction strategy presented in this paper, can effectively suppress current distortion while reducing the switching frequency. Until now, this method has been implemented with the same boundaries for both the torque component and flux component of the stator current vector. Due to the physical behavior of an induction motor, a higher current distortion tolerance of the flux component of the stator current vector can be accepted without affecting the torque. Therefore, in this work, the circular boundary restriction strategy is modified to configure larger boundaries for the flux component than for the torque component. This is done to achieve an even lower switching frequency. Furthermore, an additional improvement can be expected if only the boundaries of the torque component are strictly maintained, while the magnetizing current can exceed its boundary to some extent. The predictive control method based on this new strategy is experimentally tested to determine its feasibility. A method based on the circular boundary strategy is also implemented under the same testing conditions, and the performances of both strategies are compared.

Polythiourethane composite film with high transparency, high refractive index and low dispersion containing ZnS nanoparticle via thiol-ene click chemistry

Jianbo Gu,Xiang Wang,Chengze Xu,Xiangyang Feng,Siyuan Zhang 한국고분자학회 2023 Macromolecular Research Vol.31 No.6

In recent years, high refractive index polythiourethane materials have attracted increasing attention. In this study, the soft segment part of conventional polyurethane was replaced by ethylenedithiol, and a series of nanocomposite films containing Mercaptoethanol (ME) capped ZnS NPs were prepared by UV curing after the synthesis of the bifunctional linear prepolymer with hydroxyethyl acrylate as capping agent and trifunctional prepolymer with trimethylolpropane triacrylate as sulfhydrylate capping. ZnS NPs were well dispersed in the resin system, and the transmittance of the film decreased with the increase of ZnS content, but it did not float much and still has 80% transmittance at 40%. The addition of ZnS had a significant improvement on the refractive index. The RI of the system without the addition of particles was less than 1.5, the system with 40% was greater than 1.6. It was worth noting that the Abbe number was almost greater than 30, which was in the category of low dispersion.

Rules Placement with Delay Guarantee in Combined SDN Forwarding Element

( Qinglei Qi ),( Wendong Wang ),( Xiangyang Gong ),( Xirong Que ) 한국인터넷정보학회 2017 KSII Transactions on Internet and Information Syst Vol.11 No.6

Recent studies have shown that the flow table size of hardware SDN switch cannot match the number of concurrent flows. Combined SDN Forwarding Element (CFE), which comprises several software switches and a hardware switch, becomes an alternative approach to tackle this problem. Due to the limited capacity of software switch, the way to route concurrent flows in CFE can largely affect the maximum delay that a flow suffers at CFE. As delay-guarantee is a nontrivial task for network providers with the increasing number of delay-sensitive applications, we propose an analytical model of CFE to evaluate a rules placement solution first. Next, we formulate the problem of Rules Placement with delay guarantee in CFE (RPCFE), and present the genetic-based rules placement (GARP) algorithm to solve the RPCFE problem. Further, we validate the analytical model of CFE through simulations in NS-3 and compare the performance of GARP with three benchmark algorithms.

A Distributed Implementation Algorithm for Physical Layer Security Based on Untrusted Relay Cooperation and Artificial Noise

Xiangyu Li,Xueming Wang,Xiangyang Xu,Liang Jin 한국전자통신연구원 2014 ETRI Journal Vol.36 No.1

In this letter, we consider a cooperation system with multipleuntrusted relays (URs). To keep the transmitted informationconfidential, we obtain joint channel characteristics (JCCs)through combining the channels from the source to thedestination. Then, in the null space of the JCCs, jammersconstruct artificial noise to confuse URs when the source nodebroadcasts its data. Through a distributed implementationalgorithm, the weight of each node can be obtained from itsown channel state information. Simulation results show thathigh-level security of the system can be achieved when internaland external eavesdroppers coexist.

Effect of strain amplitude and temperature on creep-fatigue behaviors of 9-12 % Cr steel

Jianfeng Mao,Jian Zhu,Xiangyang Li,Dasheng Wang,Fengping Zhong,Jichang Chen 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.5

The creep-fatigue behaviors of P92 steel under strain range of 0.3 %-0.5 % and test temperature of 600-650 °C was studied carefully in this paper. With the increase of temperature, the creep-fatigue life is significantly reduced, and more vulnerable to temperature than strain amplitude. In addition, the dislocation density decreases with increasing creep fatigue, and the martensite laths become coarser. Furthermore, the increase of strain amplitude leads to more significant secondary cracks and fatigue striation. The higher temperature causes much deeper and larger dimples. During the test, the growth and accumulation of precipitates inevitably lead to stress concentration, resulting in material fracture and destruction. Finally, the linear cumulative damage (LCD), the modified ductility exhaustion (MDE) and the frequency separation life (FSL) model are used to predict the creep-fatigue life of P92 steel, and it is found that the frequency separation life model had the highest prediction accuracy among the threes.