ZNRF1 can inhibit proliferation and stemness properties of leukemia NB4 cells

Yuechao Zhao,TongJuan Li,Lei Zhao,Jue Wang,Zhen Shang,Wei Huang,Jianfeng Zhou 한국통합생물학회 2016 Animal cells and systems Vol.20 No.4

As a newly discovered E3 ubiquitin ligase, ZNRF1 protein participates in controlling Wallerian degeneration, but the role in cancer biology has been seldom reported. We analyzed the change of proliferation, apoptosis, stemness and protein levels of AKT and STAT5 after leukemia NB4 cells were treated with ZNRF1 siRNA and with expression vector. The results showed that overexpression of ZNRF1 inhibited proliferation and increased apoptosis of NB4 cells, but ZNRF1 siRNA did not influence the proliferation and apoptosis. Over-expression of ZNRF1 diminished cancer stem cell properties and down-regulated AKT and STAT5. This is the first study to show that ZNRF1 inhibited proliferation and stemness properties of leukemia NB4 cells possibly through AKT signal and STAT5 signal.

Analysis and Control of a three-level power energy storage system with dual active bridge DC-DC converter

Zhihong Zhao,Jianfeng Zhao 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

The energy storage system plays an important role in the distributed network, and the three-level converter has a smaller du/dt of output voltage compared with the two-level converter. This paper focus on the modeling and voltage balance control of a three-level energy storage system with dual active bridge dc-dc converter. The small signal model of the dual active bridge is proposed, which enables the output voltage and current to be controlled simultaneously. Besides, an improved voltage balancing technique for a three-level converter is presented, which makes a good tradeoff between the dc-link capacitor ripple voltage attenuation and the power device switching action reduction. Finally the system is tested by MATLAB/SIMULINK, and the experimental results are presented.

Asymptotic Performance Analysis of Free-Space Optical Links with Transmit Diversity

Jianfeng Feng,Xiaohui Zhao 한국광학회 2016 Current Optics and Photonics Vol.20 No.4

The misalignment errors and fluctuations in irradiance due to atmospheric turbulence can severelydegrade the performance of free-space optical (FSO) systems. In this paper, we investigate the asymptoticbit error rate (BER) performance and diversity orders of FSO links using parallel transmit-diversity schemes. The BER expressions of FSO links with the switch-and-examine transmit (SET), switch-and-examinetransmit with post-selection (SETps), dual-branch transmit laser selection (Dual-TLS), and group transmitlaser selection (Group-TLS) schemes are derived, based on an approximate channel model. Then numericalsimulations for these four schemes in the region of high average signal-to-noise ratio (SNR) are presentedunder different channel conditions. The results show that the four transmit-diversity schemes can reducesystem complexity and overcome the limitation of peak power, without much BER deterioration.

Correlation analyses of CpG island methylation of cluster of differentiation 4 protein with gene expression and T lymphocyte subpopulation traits

Zhao, Xueyan,Wang, Yanping,Guo, Jianfeng,Wang, Jiying Asian Australasian Association of Animal Productio 2018 Animal Bioscience Vol.31 No.8

Objective: Cluster of differentiation 4 protein (CD4) gene is an important immune related gene which plays a significant role in T cell development and host resistance during viral infection. Methods: In order to unravel the relationship of CpG island methylation level of CD4 gene with its gene expression and T lymphocyte subpopulation traits, we used one typical Chinese indigenous breed (Dapulian, DP) and one commercial breed (Landrace), then predicted the CpG island of CD4 gene, determined the methylation status of CpG sites by bisulfite sequencing polymerase chain reaction (BSP), and carried out the correlation analyses of methylation frequencies of CpG sites with mRNA expression and T lymphocyte subpopulation traits. Results: There was one CpG island predicted in the upstream -2 kb region and exon one of porcine CD4 gene, which located 333 bp upstream from the start site of gene and contained nine CpG sites. The correlation analysis results indicated that the methylation frequency of CpG_2 significantly correlated with CD4 mRNA expression in the DP and Landrace combined population, though it did not reach significance level in DP and Landrace separately. Additionally, 15 potential binding transcription factors (TFs) were predicted within the CpG island, and one of them (Jumonji) contained CpG_2 site, suggesting that it may influence the CD4 gene expression through the potential binding TFs. We also found methylation frequency of CpG_2 negatively correlated with T lymphocyte subpopulation traits CD4+CD8-CD3-, CD4-CD8+CD3- and CD4+/CD8+, and positively correlated with CD4-CD8+CD3+ and CD4+CD8+CD3+ (for all correlation, p<0.01) in DP and Landrace combined population. Thus, the CpG_2 was a critical methylation site for porcine CD4 gene expression and T lymphocyte subpopulation traits. Conclusion: We speculated that increased methylation frequency of CpG_2 may lead to the decreased expression of CD4, which may have some kind of influence on T lymphocyte subpopulation traits and the immunity of DP population.

Performance Analysis of FSO Communication Systems with Photodetector Multiplexing

Jianfeng Feng,Xiaohui Zhao 한국광학회 2017 Current Optics and Photonics Vol.1 No.5

In this paper, we carry out a performance analysis of a two-user free-space optical (FSO) communicationsystem with photodetector multiplexing, in which the two users are defined as the primary user (PU) andsecondary user (SU). Unlike common single-user FSO systems, our photodetector multiplexing FSO systemdeploys a shared detector at the receiver and enables PU and SU to send their own data synchronously. We conduct the performance analysis of this FSO system for two cases: (1) in the absence of backgroundradiation, and (2) in the presence of background radiation. Decision strategies for PU and SU are presentedaccording to the two scenarios above. Exact and approximate conditional symbol-error probability (SEP)expressions for both PU and SU are derived, in an ideal channel with no fading. Average SEP expressionsare also presented in the no-background-radiation scenario. Additionally, in some particular cases wherethe power ratio tends to 0.5 or 1, approximate SEP expressions are also obtained. Finally, numericalsimulations are presented under different conditions, to support the performance analysis.

A New Anthracene-based Small Molecule as Cathode Interlayer for Efficient Polymer Solar Cells

Jianfeng Li,Chuang Zhao,Peng Zhang,Junfeng Tong,Chunyan Yang,Yangjun Xia,Duowang Fan 대한화학회 2015 Bulletin of the Korean Chemical Society Vol.36 No.4

A new small molecule with excellent electron-transporting property, namely 9,10-bis(2-(N-octyl-1,8-naphthalimid-4-yl)ethynyl)anthracene (BNA), is prepared and characterized. A polymer solar cell (PSC) based on poly(3-hexylthiophene) (P3HT) and [6,6]-phenylC61-butyricacidmethyl ester (PC61BM) is also fabricated by using BNA as the cathode buffer layer between the Al electrode and photoactive layer, and their influence on the performance of the PSCs is investigated. It is found that the open-circuit voltage (V oc ), short-circuit current density (J sc ), and power conversion efficiency (PCE) of a device with a 6-nm BNA layer improved to 0.63 V, 9.74 mA/cm2, and 3.74%, respectively, which correspond to an increase of 53.6%, 38.0%, and 177% compared to those without the buffer layer. The BNA buffer layer could effectively improve the interfacial contact performance between the Al electrode and photoactive layer, decrease the series resistance, and improve the collection efficiency of carriers. The devices with appropriate thickness of the BNA buffer layer can also replace the common low-work-function metal Ca for increasing the PCE and lifetime of PSCs.

Improved charge collection efficiency of hollow sphere/nanoparticle composite TiO2 electrodes for solid state dye sensitized solar cells

Minggang Zhao,Xinchang Wang,Jipeng Cheng,Li-wei Zhang,Jianfeng Jia,Xin-Jian Li 한국물리학회 2013 Current Applied Physics Vol.13 No.2

Undoped and Al-doped ZnO nanofibers were synthesized via a simple electrospinning method, and then characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman scattering and photoluminescence (PL) spectroscopy. The ethanol sensing properties of the sensor based on the nanofibers were also investigated. The results show that the sensor fabricated from Al-doped ZnO nanofibers exhibits better gas sensing performance than that fabricated from the undoped ZnO nanofibers, and the gas sensing mechanism is discussed.

A Novel Method to Calculate the Carbides Fraction from Dilatometric Measurements During Cooling in Hot‑Work Tool Steel

Xiaoli Zhao,Chuanwei Li,Lizhan Han,Jianfeng Gu 대한금속·재료학회 2018 METALS AND MATERIALS International Vol.24 No.6

Dilatometry is a useful technique to obtain experimental data concerning transformation. In this paper, a dilation conversionalmodel was established to calculate carbides fraction in AISI H13 hot-work tool steel based on the measured length changes. After carbides precipitation, the alloy contents in the matrix changed. In the usual models, the content of carbon atoms afterprecipitation is considered as the only element that affects the lattice constant and the content of the alloy elements suchas Cr, Mo, Mn, V are often ignored. In the model introduced in this paper, the alloying elements (Cr, Mo, Mn, V) changescaused by carbides precipitation are incorporated. The carbides were identified using scanning electron microscope andtransmission electron microscope. The relationship between lattice constant of carbides and temperature are measured byhigh-temperature X-ray diffraction. The results indicate that the carbides observed in all specimens cooled at different ratesare V-rich MC and Cr-rich M23C6,and most of them are V-rich MC, only very few are Cr-rich M23C6. The model includingthe effects of substitutional alloying elements shows a good improvement on carbides fraction predictions. In addition, lowercooling rate advances the carbides precipitation for AISI H13 specimens. The results between experiments and mathematicalmodel agree well.

Polyaniline/graphene nanocomposites synthesized by in situ high gravity chemical oxidative polymerization for supercapacitor

Yibo Zhao,Moses Arowo,Wei Wu,Haikui Zou,Jianfeng Chen,Guangwen Chu 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.25 No.-

Polyaniline/graphene (PANI/GN) nanocomposites were synthesized by in situ high gravity chemical oxidative polymerization in a rotating packed bed (RPB). The effects of graphene dosage, ammonium persulfate/aniline mole ratio, aniline concentration and reactor type on their morphology and electrochemical performances were discussed in detail. Results indicated that this process can synthesize PANI/GN nanocomposites easily under relatively extensive conditions. Particularly, it was demonstrated that it is appropriate for higher aniline concentration condition, which is favorable for large scale production. Furthermore, RPB produced PANI/GN nanocomposites of more uniform morphology and thinner coating than those synthesized in a stirred tank reactor (STR). These advantages resulted in nanocomposites of higher specific capacitance of up to 403 F/g as compared to 255 F/g for those of STR at 0.5 A/g. This process is not only simple and efficient, but also has a good prospect for industrial application.

Fault-Tolerant Control of Cascaded H-Bridge Converters Using Double Zero-Sequence Voltage Injection and DC Voltage Optimization

Zhendong Ji,Jianfeng Zhao,Yichao Sun,Xiaojun Yao,Zean Zhu 전력전자학회 2014 JOURNAL OF POWER ELECTRONICS Vol.14 No.5

Cascaded H-Bridge (CHB) converters can be directly connected to medium-voltage grids without using transformers and they possess the advantages of large capacity and low harmonics. They are significant tools for providing grid connections in large-capacity renewable energy systems. However, the reliability of a grid-connected CHB converter can be seriously influenced by the number of power switching devices that exist in the structure. This paper proposes a fault-tolerant control strategy based on double zero-sequence voltage injection and DC voltage optimization to improve the reliability of star-connected CHB converters after one or more power units have been bypassed. By injecting double zero-sequence voltages into each phase cluster, the DC voltages of the healthy units can be rapidly balanced after the faulty units are bypassed. In addition, optimizing the DC voltage increases the number of faulty units that can be tolerated and improves the reliability of the converter. Simulations and experimental results are shown for a seven-level three-phase CHB converter to validate the efficiency and feasibility of this strategy.