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Zhihua Zheng,Jiasi Chen,Keping Wu,Yan Lei,Mingcheng Huang,Lokyu Cheng,Hui Guan,Jiawen Lin,Ming Zhong,Xiaohua Wang 대한내분비학회 2023 Endocrinology and metabolism Vol.38 No.2
Background: Ferroptosis, which is caused by an iron-dependent accumulation of lipid hydroperoxides, is a type of cell death linked todiabetic kidney disease (DKD). Previous research has shown that fatty acid binding protein 4 (FABP4) is involved in the regulation of ferroptosis in diabetic retinopathy. The present study was constructed to explore the role of FABP4 in the regulation of ferroptosis in DKD. Methods: We first detected the expression of FABP4 and proteins related to ferroptosis in renal biopsies of patients with DKD. Then, we used a FABP4 inhibitor and small interfering RNA to investigate the role of FABP4 in ferroptosis induced by high glucosein human renal proximal tubular epithelial (HG-HK2) cells. Results: In kidney biopsies of DKD patients, the expression of FABP4 was elevated, whereas carnitine palmitoyltransferase-1A (CPT1A), glutathione peroxidase 4, ferritin heavy chain, and ferritin light chain showed reduced expression. In HG-HK2 cells, the induction of ferroptosis was accompanied by an increase in FABP4. Inhibition of FABP4 in HG-HK2 cells changed the redox state, suppressing the production of reactive oxygen species, ferrous iron (Fe2+), and malondialdehyde, increasing superoxide dismutase, and reversing ferroptosis-associated mitochondrial damage. The inhibition of FABP4 also increased the expression of CPT1A, reversed lipiddeposition, and restored impaired fatty acid β-oxidation. In addition, the inhibition of CPT1A could induce ferroptosis in HK2 cells. Conclusion: Our results suggest that FABP4 mediates ferroptosis in HG-HK2 cells by inhibiting fatty acid β-oxidation.
Characterizations of geometrical properties of Banach spaces using Ψ-direct sums
Zhihua Zhang,Lan Shu,Jun Zheng,Yuling Yang 대한수학회 2013 대한수학회보 Vol.50 No.2
Let X be a Banach space and Ψ a continuous convex function on ∇K+1 satisfying certain conditions. Let (X⊕X⊕· · ·⊕X)Ψ be the Ψ-direct sum of X. In this paper, we characterize the K strict convexity, K uniform convexity and uniform non-lN 1 -ness of Banach spaces using -direct sums.
CHARACTERIZATIONS OF GEOMETRICAL PROPERTIES OF BANACH SPACES USING ψ-DIRECT SUMS
Zhang, Zhihua,Shu, Lan,Zheng, Jun,Yang, Yuling Korean Mathematical Society 2013 대한수학회보 Vol.50 No.2
Let X be a Banach space and ${\psi}$ a continuous convex function on ${\Delta}_{K+1}$ satisfying certain conditions. Let $(X{\bigoplus}X{\bigoplus}{\cdots}{\bigoplus}X)_{\psi}$ be the ${\psi}$-direct sum of X. In this paper, we characterize the K strict convexity, K uniform convexity and uniform non-$l^N_1$-ness of Banach spaces using ${\psi}$-direct sums.
Frequency Synchronization of Three-Phase Grid-Connected Inverters Controlled as Current Supplies
Zhenbin Fu,Zhihua Feng,Xi Chen,Xinxin Zheng,Jing Yin 전력전자학회 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.5
In a three-phase system, three-phase AC signals can be translated into two-phase DC signals through a coordinate transformation. Thus, the PI regulator can realize a zero steady-state error for the DC signals. In the control of a three-phase grid-connected inverter, the phase angle of grid is normally detected by a phase-locked loop (PLL) and takes part in a coordinate transformation. A novel control strategy for a three-phase grid-connected inverter with a frequency-locked loop (FLL) based on coordinate transformation is proposed in this paper. The inverter is controlled as a current supply. The grid angle, which takes part in the coordinate transformation, is replaced by a periodic linear changing angle from –π to π. The changing angle has the same frequency but a different phase than the grid angle. The frequency of the changing angle tracks the grid frequency by the negative feedback of the reactive power, which forms a FLL. The control strategy applies to non-ideal grids and it is a lot simpler than the control strategies with a PLL that are applied to non-ideal grids. The structure of the FLL is established. The principle and advantages of the proposed control strategy are discussed. The theoretical analysis is confirmed by experimental results.
High-Reliability Three-Phase Dual-Buck Grid-Connected Inverter without Shoot-Through Problem
Zhenbin Fu,Zhihua Feng,Xi Chen,Xinxin Zheng 전력전자학회 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.2
When compared to traditional bridge-type inverters, the dual-buck inverter has a higher reliability due to the fact that its bridge legs do not have a shoot-through problem. In this paper, the working principle of the dual-buck inverter is analyzed. A comparison of the working modes under full-cycle and half-cycle control is discussed. With half-cycle control, the inverter can realize a higher efficiency. However, this results in current zero-crossing distortion. The corresponding control strategy of the dual-buck inverter is proposed in order to realize both high efficiency and low current harmonic distortion. In addition, the system stability is analyzed. Dead-time is unnecessary due to the advantages of the topology. Thus, the current harmonic distortion can be further reduced. An inverter with the proposed control strategy has the advantages of high reliability, high efficiency and low current harmonic distortion. Finally, simulation and experimental results are given to verify the theoretical analysis.
Frequency Synchronization of Three-Phase Grid-Connected Inverters Controlled as Current Supplies
Fu, Zhenbin,Feng, Zhihua,Chen, Xi,Zheng, Xinxin,Yin, Jing The Korean Institute of Power Electronics 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.5
In a three-phase system, three-phase AC signals can be translated into two-phase DC signals through a coordinate transformation. Thus, the PI regulator can realize a zero steady-state error for the DC signals. In the control of a three-phase grid-connected inverter, the phase angle of grid is normally detected by a phase-locked loop (PLL) and takes part in a coordinate transformation. A novel control strategy for a three-phase grid-connected inverter with a frequency-locked loop (FLL) based on coordinate transformation is proposed in this paper. The inverter is controlled as a current supply. The grid angle, which takes part in the coordinate transformation, is replaced by a periodic linear changing angle from $-{\pi}$ to ${\pi}$. The changing angle has the same frequency but a different phase than the grid angle. The frequency of the changing angle tracks the grid frequency by the negative feedback of the reactive power, which forms a FLL. The control strategy applies to non-ideal grids and it is a lot simpler than the control strategies with a PLL that are applied to non-ideal grids. The structure of the FLL is established. The principle and advantages of the proposed control strategy are discussed. The theoretical analysis is confirmed by experimental results.
A 2-40 Gb/s PAM4/NRZ Dual-mode Wireline Transmitter with 4:1 MUX in 65-nm CMOS
Fangxu Lv,Xuqiang Zheng,Feng Zhao,Jianye Wang,Ziqiang Wang,Shuai Yuan,Yajun He,Chun Zhang,Zhihua Wang 대한전자공학회 2018 Journal of semiconductor technology and science Vol.18 No.2
This paper presents a 2-40 Gb/s dual-mode wireline transmitter supporting the four-level pulse amplitude modulation (PAM4) and non-return-tozero (NRZ) modulation with a multiplexer (MUX)-based two-tap feed-forward equalizer (FFE). An edgeacceleration technique is proposed for the 4:1 MUX to increase the bandwidth. By utilizing a dedicated cascode current source, the output swing can achieve 900 mV with a level deviation of only 0.12% for PAM4. Fabricated in a 65-nm CMOS process, the transmitter consumes 117 mW and 89 mW at 40 Gb/s in PAM4 and NRZ at 1.2 V supply.
High-Reliability Three-Phase Dual-Buck Grid-Connected Inverter without Shoot-Through Problem
Fu, Zhenbin,Feng, Zhihua,Chen, Xi,Zheng, Xinxin The Korean Institute of Power Electronics 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.2
When compared to traditional bridge-type inverters, the dual-buck inverter has a higher reliability due to the fact that its bridge legs do not have a shoot-through problem. In this paper, the working principle of the dual-buck inverter is analyzed. A comparison of the working modes under full-cycle and half-cycle control is discussed. With half-cycle control, the inverter can realize a higher efficiency. However, this results in current zero-crossing distortion. The corresponding control strategy of the dual-buck inverter is proposed in order to realize both high efficiency and low current harmonic distortion. In addition, the system stability is analyzed. Dead-time is unnecessary due to the advantages of the topology. Thus, the current harmonic distortion can be further reduced. An inverter with the proposed control strategy has the advantages of high reliability, high efficiency and low current harmonic distortion. Finally, simulation and experimental results are given to verify the theoretical analysis.