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Yu Dong,Liqin Liu,Zhe Zhao,Huanhuan Zhi,Junfeng Guan 한국원예학회 2015 Horticulture, Environment, and Biotechnology Vol.56 No.2
1-methylcyclopropene (1-MCP) has been shown to delay fruit ripening and senescence during storage. In this study, we investigated the effects of 1.0 μL·L-1 1-MCP on the biochemical changes and cellular ultra-structure of the core tissue in ‘Yali’ pear (Pyrus bretschneideri Rehd.) fruits stored at 25 ± 2°C. Our results showed that 1-MCP treatment significantly decreased the rates of respiration and ethylene production before their climacteric peaks, inhibited the development of core browning, lowered the chlorogenic acid content and polyphenol oxidase activity before the onset of core browning, and preserved high levels of superoxide dismutase activity, ascorbic acid, and glutathione contents. Furthermore, it suppressed the accumulation of hydrogen peroxide, superoxide anion, and malondialdehyde in the core tissue, maintained the integral structure of the cell membrane and organelle, and delayed the accumulation of electron-opaque matters in the vacuoles of core cells. These results suggested that 1-MCP treatment could reduce the injury caused by reactive oxygen, inhibit the oxidation of phenolics, and keep the cell membrane intact in core cells, thus, delaying the core browning in ‘Yali’ pear during storage.
Yu Dong,Liqin Liu,Yingying Zhang,Junfeng Guan 한국원예학회 2014 Horticulture, Environment, and Biotechnology Vol.55 No.5
‘Jingbaili’ pear (Pyrus ussuriensis Maxim.) fruit shows rapid softening, yellowing and short shelf-life atambient temperature storage. In this study, ‘Jingbaili’ pear fruits were treated with 1.0 μL·L-1 1-methylcyclopropene(1-MCP) for 24 hours at 25 ± 2°C and then stored at 0°C. After 60 and 120 days of cold storage at 0°C, pearfruits were removed and stored at 20 ± 2°C to assess their shelf-life. The results indicated that the 1-MCP treatmentdelayed the decrease in firmness and chlorophyll (a, b, and a+b) content of peel, reduced the rates of respiration andethylene production, and inhibited the accumulation of hydrogen peroxide (H2O2), which was observed in the untreatedfruits during and after cold storage. Less difference was found in soluble solids content (SSC) between the controland 1-MCP-treated fruits during storage. The correlation analysis showed that flesh H2O2 content was negativelyrelated to firmness and also peel H2O2 content to peel chlorophyll a+b content. These results suggested that the1-MCP treatment could delay the fruit softening and chlorophyll degradation by suppressing the accumulation ofH2O2 content during and after cold storage in ‘Jingbaili’ pear.
A Wearable Pressure Sensor Based on Ionogel/Textile for Human Motion Monitoring
Yu Dong,Qiujin Li,Zhiqi Zhao,Jixian Gong,Zheng Li,Jianfei Zhang 한국섬유공학회 2022 Fibers and polymers Vol.23 No.8
The growth of flexible sensors has always been challenging since the sensing behavior, mechanic performance andfatigue resistance remain to be improved. In this paper, a wearable pressure sensor with fast response and high sensitivitybased on ionogel/textile is fabricated. The ionogel is a double-network (DN) structure composed of polydimethylacrylamide(PDMAAm) skeleton and silica particles, carrying ionic liquids (ILs), which serves as a piezoresistive device. Byimpregnating and polymerization with the ionogel-prepolymer solution, a conventional cotton knitted fabric is converted intoa conductive and piezoresistive composite. The fabric serves as a ductile supporting matrix for the ionogel, supplementing thepiezoresistive contribution of the brittle silica network. This ionogel/textile composite has a high sensitivity (S=86.90 kPa-1)and durability, continuously outputting stable electric signal during monitoring the motion states of different joints in humanbody. Through the impregnation-polymerization approach, the selected areas toward to the specific joints positions inclothing can be fabricated into piezoresistive devices. The incorporation of textile improves the stress loading and sensingbehavior of the ionogel to work steadily under the sole of the foot for gait monitoring. This ionogel/textile device provides apotential formula of wearable sensors, stepping toward the burgeoning diversified-technologies assisted intelligence system.
Caveolin‐1 deficiency induces premature senescence with mitochondrial dysfunction
Yu, Dong‐,Min,Jung, Seung Hee,An, Hyoung‐,Tae,Lee, Sungsoo,Hong, Jin,Park, Jun Sub,Lee, Hyun,Lee, Hwayeon,Bahn, Myeong‐,Suk,Lee, Hyung Chul,Han, Na‐,Kyung,Ko, Jesang,Lee, Jae BLACKWELL PUBLISHING 2017 AGING CELL Vol.16 No.4
<P><B>Summary</B></P><P>Paradoxical observations have been made regarding the role of caveolin‐1 (Cav‐1) during cellular senescence. For example, caveolin‐1 deficiency prevents reactive oxygen species‐induced cellular senescence despite mitochondrial dysfunction, which leads to senescence. To resolve this paradox, we re‐addressed the role of caveolin‐1 in cellular senescence in human diploid fibroblasts, A549, HCT116, and Cav‐1<SUP><I>−/−</I></SUP> mouse embryonic fibroblasts. Cav‐1 deficiency (knockout or knockdown) induced cellular senescence via a p53‐p21‐dependent pathway, downregulating the expression level of the cardiolipin biosynthesis enzymes and then reducing the content of cardiolipin, a critical lipid for mitochondrial respiration. Our results showed that Cav‐1 deficiency decreased mitochondrial respiration, reduced the activity of oxidative phosphorylation complex I (CI), inactivated SIRT1, and decreased the NAD<SUP>+</SUP>/NADH ratio. From these results, we concluded that Cav‐1 deficiency induces premature senescence via mitochondrial dysfunction and silent information regulator 2 homologue 1 (SIRT1) inactivation.</P>
Yudong Zhao,Yueyuan Zhang,이장명 제어·로봇·시스템학회 2019 International Journal of Control, Automation, and Vol.17 No.5
In this paper, a new two-layer control strategy which combines Kinematic Controller based on LyapunovTheory (KCLT) with Dynamic Controller based on Sliding Mode (DCSM) is proposed to solve the problem ofleader-follower formation control for multiple wheeled mobile robots (M-WMR). An augmented distance-angleleader-follower formation kinematic is constructed to describe the formation states, and a 2D LiDAR sensor is utilizedto measure the states instead of using camera and image processing on each follower. Instead of transferringthe measured formation states into reference position command for each follower, KCLT is designed to generatefollower’s velocity command. By taking the velocity command of followers as reference signals, DCSM is implementedto realize formation control. Lyapunov stability theory verifies that with the designed controller all the errorsignals can converge to 0 theoretically, which implies formation control of M-WMR under the proposed methodcan be realized. Real experiments with one leader and two followers are carried out to demonstrate the effectivenessof the proposed control schema. In order to verify the robustness of the proposed method, the reference rotationalvelocity of the leader robot is designed to change between +0:2 rad/s and 0:2 rad/s at some specified position. And the experimental results are compared with that of traditional proportional-integral-derivative (PID) method.
Research on surface image acquisition system of train bearing cylindrical roller
Yudong Bao,Linkai Wu,Ye Dai,Yanling Zhao,Siming Wei 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.9
The acquisition of high-quality surface images is an important step in the surface damage detection of bearing rollers. In order to improve the quality of image acquisition and take into account the acquisition efficiency, an image acquisition system is designed in this paper. Through the dynamic analysis method, it is proved that the amplitude of the roller itself has little effect on the image in the acquisition process. Subsequently, the response surface method is used to analyze the interactive effect of the light source intensity, incident angle and roller speed on the image quality, and the optimal acquisition parameter setting value suitable for this acquisition system is found. Finally, the image of the bearing cylindrical roller with surface defects is collected to obtain a clear surface image. This paper can provide reference for the design of high level image acquisition system.
Balancing control of Mobile Manipulator with Sliding mode Controller
Yudong Zhao,Changjun Woo,Jangmyung Lee 제어로봇시스템학회 2015 제어로봇시스템학회 국제학술대회 논문집 Vol.2015 No.10
This paper proposes an attitude control system to keep the balance of a two-wheeled mobile manipulator which consists of a mobile platform and a three D.O.F. manipulator. In the conventional control scheme, complicated dynamics is utilized for balancing control of a mobile manipulator. In this paper, however, three links are considered as one body and the dynamics is derived easily by using inverted pendulum model. sliding mode controller is characterized as low sensitivity to plant parameter uncertainties and disturbances and non-necessity of an explicit model of the system. Therefore, it is adopted in this research for the attitude control of mobile platform with respect to the pitch axis. The center of gravity for the whole mobile manipulator is changing along with the motion of the manipulator. And the orientation variation of center of gravity is used as reference input for the sliding mode controller to maintain the center of gravity in the middle of robot so that the whole system can keep balance. To confirm the performance of the controller proposed in this paper, MATLAB Simulink has been used and an experiment is carried out to demonstrate the superiority of the proposed attitude control.