Effect of TNF-α and IL-6 on Compact Bone-Derived Cells

Zhang Yiming,Li Xianqi,Chihara Takahiro,Dong Hongwei,Kagami Hideaki 한국조직공학과 재생의학회 2021 조직공학과 재생의학 Vol.18 No.3

Background: Although bone tissue engineering has already been applied clinically, its regeneration efficacy is not always sufficient. Local inflammatory cytokines are considered as the major factors that induce apoptosis of transplanted cells, thus leading to insufficient new bone formation. In this study, we focused on the effects of interleukin (IL)-6 and tumor necrosis factor-alpha (TNF-α) on differentiation and apoptosis of compact bone-derived cells (CBDCs). Methods: CBDCs were obtained from mouse legs and cultured. The effects of TNF-α and/or IL-6 on the osteogenic differentiation and apoptosis of CBDCs were analyzed in vitro. To confirm the expression of local inflammatory cytokines in vivo, CBDCs were transplanted to the back of immunocompetent mice. Results: IL-6 exerted inconsistent effects on the expression of the different osteogenic markers tested, while significantly upregulating Fas. By contrast, the addition of TNF-α dramatically reduced the expression of all tested osteogenic markers and increased Fas expression. The highest dose of IL-6 could partially reverse the repressive effect of TNF-α, while the addition of IL-6 further increased Fas expression in CBDCs compared to TNF-α alone. The results from in vivo experiments showed the presence of transplants with and without new bone formation. The transplants without bone formation were characterized by higher IL-6 and lower IL-10 expression than those with bone formation, while the expression of TNF-α did not show notable difference. Conclusion: The results of this study suggest an important role for IL-6 in modulating the efficacy of bone tissue engineering, which can affect osteogenic cells both positively and negatively. Background: Although bone tissue engineering has already been applied clinically, its regeneration efficacy is not always sufficient. Local inflammatory cytokines are considered as the major factors that induce apoptosis of transplanted cells, thus leading to insufficient new bone formation. In this study, we focused on the effects of interleukin (IL)-6 and tumor necrosis factor-alpha (TNF-α) on differentiation and apoptosis of compact bone-derived cells (CBDCs). Methods: CBDCs were obtained from mouse legs and cultured. The effects of TNF-α and/or IL-6 on the osteogenic differentiation and apoptosis of CBDCs were analyzed in vitro. To confirm the expression of local inflammatory cytokines in vivo, CBDCs were transplanted to the back of immunocompetent mice. Results: IL-6 exerted inconsistent effects on the expression of the different osteogenic markers tested, while significantly upregulating Fas. By contrast, the addition of TNF-α dramatically reduced the expression of all tested osteogenic markers and increased Fas expression. The highest dose of IL-6 could partially reverse the repressive effect of TNF-α, while the addition of IL-6 further increased Fas expression in CBDCs compared to TNF-α alone. The results from in vivo experiments showed the presence of transplants with and without new bone formation. The transplants without bone formation were characterized by higher IL-6 and lower IL-10 expression than those with bone formation, while the expression of TNF-α did not show notable difference. Conclusion: The results of this study suggest an important role for IL-6 in modulating the efficacy of bone tissue engineering, which can affect osteogenic cells both positively and negatively.

Comparative study on predictive dead-beat peak current, valley current and average current control algorithms for phase-shifted full-bridge DC/DC converters

Zhang, Yu,Zhang, Yiming,Wang, Xuhong The Korean Institute of Power Electronics 2020 JOURNAL OF POWER ELECTRONICS Vol.20 No.1

Three types of digital predictive dead-beat current control algorithms (PDB-CCAs) for phase-shifted full-bridge DC-DC converters with peak current, valley current and average current are presented. The PDB-CCAs are derived directly from the switching characteristics and topological structures of the converters. The proposed algorithms can predict the inductor current in the next switching period by sampling the input voltage, output voltage and inductor current in the current switching period. To ensure the stability of the inductor current, the PDB-CCAs result in a greatly improved transient performance, since the inductor current tracks the reference in one switching period or less when a reference perturbation or current perturbation occurs. In addition, although the procedure for deriving the control algorithms is complex, they can be easily implemented by a digital controller after reasonable simplification. Finally, simulation and experimental results are obtained and they agree with the theoretical results, which demonstrate the validity of the proposed PDB-CCAs.

Adaptive Digital Predictive Peak Current Control Algorithm for Buck Converters

Zhang, Yu,Zhang, Yiming,Wang, Xuhong,Zhu, Wenhao The Korean Institute of Power Electronics 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.3

Digital current control techniques are an attractive option for DC-DC converters. In this paper, a digital predictive peak current control algorithm is presented for buck converters that allows the inductor current to track the reference current in two switching cycles. This control algorithm predicts the inductor current in a future period by sampling the input voltage, output voltage and inductor current of the current period, which overcomes the problem of hardware periodic delay. Under the premise of ensuring the stability of the system, the response speed is greatly improved. A real-time parameter identification method is also proposed to obtain the precision coefficient of the control algorithm when the inductance is changed. The combination of the two algorithms achieves adaptive tracking of the peak inductor current. The performance of the proposed algorithms is verified using simulations and experimental results. In addition, its performance is compared with that of a conventional proportional-integral (PI) algorithm.

Model Predictive Power Control of a PWM Rectifier for Electromagnetic Transmitters

Zhang, Jialin,Zhang, Yiming,Guo, Bing,Gao, Junxia The Korean Institute of Power Electronics 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.3

Model predictive direct power control (MPDPC) is a widely recognized high-performance control strategy for a three-phase grid-connected pulse width modulation (PWM) rectifier. Unlike those of conventional grid-connected PWM rectifiers, the active and reactive powers of permanent magnet synchronous generator (PMSG)-connected PWM rectifiers, which are used in electromagnetic transmitters, cannot be calculated as the product of voltage and current because the back electromotive force (EMF) of the generator cannot be measured directly. In this study, the predictive power model of the rectifier is obtained by analyzing the relationship among flux, back EMF, active/reactive power, converter voltage, and stator current of the generator. The concept of duty cycle control in the proposed MPDPC is introduced by allocating a fraction of the control period for a nonzero vector and rest time for a zero vector. When nonzero vectors and their duration in the predefined cost function are simultaneously evaluated, the global power ripple minimization is obtained. Simulation and experimental results prove that the proposed MPDPC strategy with duty cycle control for the PMSG-connected PWM rectifier can achieve better control performance than the conventional MPDPC-SVM with grid-connected PWM rectifier.

Comparison of lithium iron phosphate blended with different carbon sources for lithium battery electrodes

Zhang Yiming 한국탄소학회 2024 Carbon Letters Vol.34 No.3

In response to the growing demand for high-performance lithium-ion batteries, this study investigates the crucial role of different carbon sources in enhancing the electrochemical performance of lithium iron phosphate (LiFePO4) cathode materials. Lithium iron phosphate (LiFePO4) suffers from drawbacks, such as low electronic conductivity and low lithium-ion diffusion coefficient, which hinder its industrial development. Carbon is a common surface coating material for LiFePO4, and the source, coating method, coating amount, and incorporation method of carbon have a significant impact on the performance of LiFePO4 materials. In this work, iron phosphate was used as the iron and phosphorus source, and lithium carbonate was used as the lithium source. Glucose, phenolic resin, ascorbic acid, and starch were employed as carbon sources. Ethanol was utilized as a dispersing agent, and ball milling was employed to obtain the LiFePO4 precursor. Carbon-coated LiFePO4 cathode materials were synthesized using the carbothermal reduction method, and the effects of different carbon sources on the structure and electrochemical performance of LiFePO4 materials were systematically investigated. The results showed that, compared to other carbon sources, LiFePO4 prepared with glucose as the carbon source not only had a higher discharge specific capacity but also better rate cycle performance. Within a voltage range of 2.5–4.2 V, the initial discharge specific capacities at 0.1, 0.5, and 1 C rates were 154.6, 145.6, and 137.6 mAh/g, respectively. After 20 cycles at a 1 C rate, the capacity retention rate was 98.7%, demonstrating excellent electrochemical performance.

Probing the origin of the enhanced catalytic performance of sp³@sp² nanocarbon supported Pd catalyst for CO oxidation

Zhang, Liyun,Ding, Yuxiao,Koh, Yoobin Esther,Mun, Bongjin Simon,Wu, Kuang-Hsu,Niu, Yiming,Shi, Wen,Zhang, Bingsen Elsevier 2020 Carbon Vol.156 No.-

<P><B>Abstract</B></P> <P>Tuning the fine structure of carbon support is crucial for modifying the metal-support interface (MSI) in order to harvest a high-performance catalysis. Herein, a core–shell sp<SUP>3</SUP>@sp<SUP>2</SUP> nanocarbon (nanodiamond@graphene, ND@G) and a pure sp<SUP>2</SUP> carbon derivative (onion-like carbon, OLC) were applied to support Pd nanoparticles. We found that Pd/ND@G displayed a superior catalytic activity for CO oxidation reaction with a TOF of 2.9 times higher than that of Pd/OLC at 46 °C. Aberration-corrected high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and ambient pressure X-ray photoelectron spectroscopy (AP-XPS) revealed that, different with the Pd/OLC system, a unique interface microstructure was formed in Pd/ND@G, which not only provides a high exposure of active sites, but also enhances the Pd surface reactivity toward oxygen species, thus leading to a superior catalytic activity of Pd/ND@G. Moreover, the temperature-programmed surface reaction (TPSR) results showed that CO oxidation on Pd/ND@G undergoes an unusual termolecular Eley–Rideal (TER) mechanism, which has a lower energy barrier as compared to the traditional Langmuir-Hinshelwood (LH) and ER mechanism.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Model Predictive Power Control of a PWM Rectifier for Electromagnetic Transmitters

Jialin Zhang,Yiming Zhang,Bing Guo,Junxia Gao 전력전자학회 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.3

Model predictive direct power control (MPDPC) is a widely recognized high-performance control strategy for a three-phase grid-connected pulse width modulation (PWM) rectifier. Unlike those of conventional grid-connected PWM rectifiers, the active and reactive powers of permanent magnet synchronous generator (PMSG)-connected PWM rectifiers, which are used in electromagnetic transmitters, cannot be calculated as the product of voltage and current because the back electromotive force (EMF) of the generator cannot be measured directly. In this study, the predictive power model of the rectifier is obtained by analyzing the relationship among flux, back EMF, active/reactive power, converter voltage, and stator current of the generator. The concept of duty cycle control in the proposed MPDPC is introduced by allocating a fraction of the control period for a nonzero vector and rest time for a zero vector. When nonzero vectors and their duration in the predefined cost function are simultaneously evaluated, the global power ripple minimization is obtained. Simulation and experimental results prove that the proposed MPDPC strategy with duty cycle control for the PMSG-connected PWM rectifier can achieve better control performance than the conventional MPDPC-SVM with grid-connected PWM rectifier.

Adaptive Digital Predictive Peak Current Control Algorithm for Buck Converters

Yu Zhang,Yiming Zhang,Xuhong Wang,Wenhao Zhu 전력전자학회 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.3

Digital current control techniques are an attractive option for DC-DC converters. In this paper, a digital predictive peak current control algorithm is presented for buck converters that allows the inductor current to track the reference current in two switching cycles. This control algorithm predicts the inductor current in a future period by sampling the input voltage, output voltage and inductor current of the current period, which overcomes the problem of hardware periodic delay. Under the premise of ensuring the stability of the system, the response speed is greatly improved. A real-time parameter identification method is also proposed to obtain the precision coefficient of the control algorithm when the inductance is changed. The combination of the two algorithms achieves adaptive tracking of the peak inductor current. The performance of the proposed algorithms is verified using simulations and experimental results. In addition, its performance is compared with that of a conventional proportional-integral (PI) algorithm.

A Secret Sharing Scheme Based on AES

Jie Cui,Lei Chen,Yiming Zhang,Zhiqiang Xie,Hong Zhong 보안공학연구지원센터 2014 International Journal of Security and Its Applicat Vol.8 No.6

In order to solve the key setting difficulty and the key security problem in the file encryption, key distributed storage technology may be a proper choice to help improve the safety of the key. In the paper, a novel secret sharing scheme is proposed by AES encryption algorithm for file confidentiality, dynamic key generation mechanism to generate keys, multi-secret-sharing ideas on key pre-treatment, using Shamir threshold scheme for secret dispersed storage. Finally, a few tests are carried out and the test results suggest that the efficiency of the whole scheme is good.

Cloud monitoring system for assembled beam bridge based on index of dynamic strain correlation coefficient

Yiming Zhao,Danhui Dan,Xingfei Yan,Kailong Zhang 국제구조공학회 2020 Smart Structures and Systems, An International Jou Vol.26 No.1

The hinge joint is the key to the overall cooperative working performance of the assembled beam bridge, and it is also the weakest part during the service period. This paper proposes a method for monitoring and evaluating the lateral cooperative working performance of fabricated beam bridges based on dynamic strain correlation coefficient indicator. This method is suitable for monitoring and evaluation of hinge joints status between prefabricated girders and overall cooperative working performance of bridge, without interruption of traffic and easy implementation. The remote cloud monitoring and diagnosis system was designed and implemented on a real assembled beam bridge. The algorithms of data preprocessing, online indicator extraction and status diagnosis were given, and the corresponding software platform and scientific computing environment for cloud operation were developed. Through the analysis of real bridge monitoring data, the effectiveness and accuracy of the method are proved and it can be used in the health monitoring system of such bridges.