An Improved Method of Maximum Power Point Tracking Strategy for Wind Power Conversion System

CHEN Ran,CHEN Jie,CHEN Jia-wei,CHEN Zhi-hui,GONG Chun-ying,YAN Yang-guang 전력전자학회 2011 ICPE(ISPE)논문집 Vol.2011 No.5

The turbine speed loop adjustment is the key link of the designing of the controller for the fixed pitch variable speed wind energy conversion systems (WECS). Because of the strong nonlinear, big inertia and mechanical damping characteristics, it’s difficult to designing the controller of the wind power systems. In this paper, a small signal model is present, and based on the analyzing; a wind turbine speed loop regulator is designed. Then, a method of tracking the peak power conversion system is proposed, which is independent of the turbine parameters and air density. At last, simulation system is built, and the results of the simulation experiments show that, the performance of the controller algorithm meet the requirements of the MPPT without wind measurement.

Investigation of Porous Structure of Aerogel Prepared from Nanofibrillated Cellulose

Chen Gong,Yu Shi,Jian-Ping Ni,Xiao-Bo Yang,Yan-Zhao Liu,Chao Tian 한국펄프·종이공학회 2016 펄프.종이기술 Vol.48 No.6

Cellulose aerogels were prepared through changing the concentration of TEMPO-oxidized cellulose suspension and applying high-pressure homogenization, followed by regular or rapid freeze drying methods. The prepared cellulose aerogel was studied by scanning electron microscopy, BET analysis (nitrogen gas adsorption), and mercury intrusion porosimetry to investigate the effect of variables on the porous properties. In the present study, the porous structure of cellulose aerogel was well obtained by varying concentration of NFC and applying rapid freeze drying approach. The specific surface area of prepared cellulose aerogels varied linearly with adjusting concentrations of NFC, and the highest surface area of cellulose aerogel was attained at 2.0% concentration of NFC in this study. Compared to regular freezing in the freezer, rapid freezing in the liquid nitrogen prepared cellulose aerogel has a lower BET value but more uniform structure with relatively narrow pore size distribution.

Accelerating the Sweep3D for a Graphic Processor Unit

Gong, Chunye,Liu, Jie,Chen, Haitao,Xie, Jing,Gong, Zhenghu Korea Information Processing Society 2011 Journal of information processing systems Vol.7 No.1

As a powerful and flexible processor, the Graphic Processing Unit (GPU) can offer a great faculty in solving many high-performance computing applications. Sweep3D, which simulates a single group time-independent discrete ordinates (Sn) neutron transport deterministically on 3D Cartesian geometry space, represents the key part of a real ASCI application. The wavefront process for parallel computation in Sweep3D limits the concurrent threads on the GPU. In this paper, we present multi-dimensional optimization methods for Sweep3D, which can be efficiently implemented on the finegrained parallel architecture of the GPU. Our results show that the overall performance of Sweep3D on the CPU-GPU hybrid platform can be improved up to 4.38 times as compared to the CPU-based implementation.

LY294002 Induces G0/G1 Cell Cycle Arrest and Apoptosis of Cancer Stem-like Cells from Human Osteosarcoma Via Down-regulation of PI3K Activity

Gong, Chen,Liao, Hui,Wang, Jiang,Lin, Yang,Qi, Jun,Qin, Liang,Tian, Lin-Qiang,Guo, Feng-Jing Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.7

Osteosarcoma, the most common primary mesenchymal malignant tumor, usually has bad prognosis in man, with cancer stem-like cells (CSCs) considered to play a critical role in tumorigenesis and drug-resistance. It is known that phosphatidylinositol 3-kinase (PI3K) is involved in regulation of tumor cell fates, such as proliferation, cell cycling, survival and apoptosis. Whether and how PI3K and inhibitors might cooperate in human osteosarcoma CSCs is still unknown. We therefore evaluated the effects of LY294002, a PI3K inhibitor, on the cell cycle and apoptosis of osteosarcoma CSCs in vitro. LY294002 prevented phosphorylation of protein kinase B (PKB/Akt) by inhibition of PI3K phosphorylation activity, thereby inducing G0/G1 cell cycle arrest and apoptosis in osteosarcoma CSCs. Further studies also demonstrated that apoptosis induction by LY294002 is accompanied by activation of caspase-9, caspase-3 and PARP, which are involved in the mitochondrial apoptosis pathway. Therefore, our results indicate PI3K inhibitors may represent a potential strategy for managing human osteosarcoma via affecting CSCs.

Plasma polymerized bio-interface directs fibronectin adsorption and functionalization to enhance “epithelial barrier structure” formation via FN-ITG β1-FAK-mTOR signaling cascade

Chen Shoucheng,Huang Zhuwei,Visalakshan Rahul Madathiparambil,Liu Haiwen,Bachhuka Akash,Wu You,Dabare Panthihage Ruvini L.,Luo Pu,Liu Runheng,Gong Zhuohong,Xiao Yin,Vasilev Krasimir,Chen Zhuofan,Chen 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00

Background: Transepithelial medical devices are increasing utilized in clinical practices. However, the damage of continuous natural epithelial barrier has become a major risk factor for the failure of epithelium-penetrating implants. How to increase the “epithelial barrier structures” (focal adhesions, hemidesmosomes, etc.) becomes one key research aim in overcoming this difficulty. Directly targeting the in situ “epithelial barrier structures” related proteins (such as fibronectin) absorption and functionalization can be a promising way to enhance interface-epithelial integration. Methods: Herein, we fabricated three plasma polymerized bio-interfaces possessing controllable surface chemistry. Their capacity to adsorb and functionalize fibronectin (FN) from serum protein was compared by Liquid Chromatography- Tandem Mass Spectrometry. The underlying mechanisms were revealed by molecular dynamics simulation. The response of gingival epithelial cells regarding the formation of epithelial barrier structures was tested. Results: Plasma polymerized surfaces successfully directed distinguished protein adsorption profiles from serum protein pool, in which plasma polymerized allylamine (ppAA) surface favored adsorbing adhesion related proteins and could promote FN absorption and functionalization via electrostatic interactions and hydrogen bonds, thus subsequently activating the ITG β1-FAK-mTOR signaling and promoting gingival epithelial cells adhesion. Conclusion: This study offers an effective perspective to overcome the current dilemma of the inferior interfaceepithelial integration by in situ protein absorption and functionalization, which may advance the development of functional transepithelial biointerfaces. Graphical Abstract: Tuning the surface chemistry by plasma polymerization can control the adsorption of fibronectin and functionalize it by exposing functional protein domains. The functionalized fibronectin can bind to human gingival epithelial cell membrane integrins to activate epithelial barrier structure related signaling pathway, which eventually enhances the formation of epithelial barrier structure.

SDC4 Gene Silencing Favors Human Papillary Thyroid Carcinoma Cell Apoptosis and Inhibits Epithelial Mesenchymal Transition via Wnt/β-Catenin Pathway

Chen, Liang-Liang,Gao, Ge-Xin,Shen, Fei-Xia,Chen, Xiong,Gong, Xiao-Hua,Wu, Wen-Jun Korean Society for Molecular and Cellular Biology 2018 Molecules and cells Vol.41 No.9

As the most common type of endocrine malignancy, papillary thyroid cancer (PTC) accounts for 85-90% of all thyroid cancers. In this study, we presented the hypothesis that SDC4 gene silencing could effectively attenuate epithelial mesenchymal transition (EMT), and promote cell apoptosis via the $Wnt/{\beta}-catenin$ signaling pathway in human PTC cells. Bioinformatics methods were employed to screen the determined differential expression levels of SDC4 in PTC and adjacent normal samples. PTC tissues and adjacent normal tissues were prepared and their respective levels of SDC4 protein positive expression, in addition to the mRNA and protein levels of SDC4, $Wnt/{\beta}-catenin$ signaling pathway, EMT and apoptosis related genes were all detected accordingly. Flow cytometry was applied in order to detect cell cycle entry and apoptosis. Finally, analyses of PTC migration and invasion abilities were assessed by using a Transwell assay and scratch test. In PTC tissues, activated $Wnt/{\beta}-catenin$ signaling pathway, increased EMT and repressed cell apoptosis were determined. Moreover, the PTC K1 and TPC-1 cell lines exhibiting the highest SDC4 expression were selected for further experiments. In vitro experiments revealed that SDC4 gene silencing could suppress cell migration, invasion and EMT, while acting to promote the apoptosis of PTC cells by inhibiting the activation of the $Wnt/{\beta}-catenin$ signaling pathway. Besides, $si-{\beta}-catenin$ was observed to inhibit the promotion of PTC cell migration and invasion caused by SDC4 overexpression. Our study revealed that SDC4 gene silencing represses EMT, and enhances cell apoptosis by suppressing the activation of the $Wnt/{\beta}-catenin$ signaling pathway in human PTC.

Porous Structure of Aerogel Made From Nanofibrillated Cellulose

Chen Gong,Yu Shi,Jian-Ping Ni,Xiao-Bo Yang,Yan-Zhao Liu,Chao Tian 한국펄프·종이공학회 2016 한국펄프·종이공학회 학술발표논문집 Vol.2016 No.10

Enhanced Salt Tolerance of Transgenic Vegetable Soybeans Resulting from Overexpression of a Novel Δ1-Pyrroline-5-carboxylate Synthetase Gene from Solanum torvum Swartz

Gong-Chen Zhang,Wen-Li Zhu,Jun-Yi Gai,Yue-Lin Zhu,Li-Fei Yang 한국원예학회 2015 Horticulture, Environment, and Biotechnology Vol.56 No.1

Vegetable soybeans [Glycine max (L.) Merrill] are susceptible to salt stress and, thus, soil salinity can severely affect their growth and productivity. To enhance the salt tolerance of vegetable soybeans, a novel Solanum torvum Swartz Δ1-pyrroline-5-carboxylate synthetase gene (StP5CS, GenBank accession number: JN606861) that encodes a critical regulatory enzyme in proline biosynthesis was transformed into the cultivar NY-1001 using an Agrobacteriummediated transformation method. PCR and Southern blot analyses indicated that two independent T0 fertile transgenic plants were generated. The transgenic plants transmitted the transgenes into their T1 progeny in a 3:1 ratio. The T2 and T3 homozygous transgenic lines (HTLs) were examined for salt tolerance in pot and hydroponic cultures, respectively. The StP5CS overexpression conferred salt tolerance in T2 and T3 HTLs. Under NaCl stress conditions, the leaf scorch scores of T2 and T3 HTLs were significantly lower than those of wild-type (WT) plants. The plant height, leaf area, relative chlorophyll content, and number of fresh pods of T2 and T3 HTLs were significantly higher than those of WT plants. Compared with WT plants, T2 and T3 HTLs had significantly higher levels of proline and significantly lower levels of membrane lipid peroxidation. These results indicate that StP5CS overexpression in HTLs results in enhanced salt tolerance associated with higher levels of proline accumulation under salinity stress and that StP5CS can be utilized to improve salinity tolerance in vegetable crop genetic engineering.

Microstructure and mechanical properties of carbon graphite composites reinforced by carbon nanofibers

Chen Yixing,Tu Chuanjun,Liu Yanli,Liu Ping,Gong Pei,Wu Guangning,Huang Xia,Chen Jian,Liu Tianhua,Jiang Jizhou 한국탄소학회 2023 Carbon Letters Vol.33 No.2

Renewed interest in the reinforced carbon graphite composites has intrigued the community in the advanced materials fields. In this work, we present a simple carbon nanofibers reinforced carbon graphite composites synthetic method by incorporating mixture of coal tar pitch, synthetic graphite, pitch coke and the dispersion liquid of carbon nanofibers via liquid-phase mixing process. The impact of carbon nanofiber utilization on the microstructures and mechanical properties of carbon graphite composites are studied systematically. The covalent surface modification of carbon nanofibers effectively improves its microstructure and thereby promotes the carbon graphite composites’ dispersion behavior. We propose that a small amount of carbon nanofibers could promote the carbonization process of carbon graphite composites, facilitating the densification of carbon graphite composites and reducing the undesired open porosity. The amount of 0.7 wt % of carbon nanofiber concentration allows the enhancement of bend and compressive strength of carbon graphite composites up to 36.50 MPa and 60.46 MPa, increased by 167.9% and 146.9% compared with the pure carbon graphite composite, respectively. Our findings can be rationalized due to the improvement in the mechanical strength of carbon graphite composites could be attributed due to pull-out of carbon nanofibers from the matrix and bridging effect across the crack pores within the matrix.

Smad4 mediates malignant behaviors of human ovarian carcinoma cell through the effect on expressions of E-cadherin, plasminogen activator inhibitor-1 and VEGF

( Chen Chen ),( Ming Zhong Sun ),( Shu Qing Liu ),( Dong Mei Yeh ),( Li Jun Yu ),( Yang Song ),( Lin Lin Gong ),( Li Hong Hao ),( Jun Hu ),( Shu Juan Shao ) 생화학분자생물학회 (구 한국생화학분자생물학회) 2010 BMB Reports Vol.43 No.8

Smad4 is involved in cancer progression and metastasis. Using a pair of human syngeneic epithelial ovarian cancer cells with low (HO-8910) and high (HO-8910PM) metastatic abilities, we aimed to reveal the role of Smad4 in ovarian cancer metastasis in vitro. Smad4 was down-regulated in HO-8910PM cell line relative to HO-8910 by implicating Smad4 was probably a potential tumor suppressor gene for ovarian cancer. Re-expression of Smad4 decreased the migration ability and inhibited the invasion capacity of HO-8910PM, while promoted the cell adhesion capacity for HO-8910PM. The stable expression of Smad4 increased the expression of E-cadherin, reduced the expression of plasminogen activator inhibitor-1 (PAI-1) and slightly down-regulated the expression of VEGF. Smad4 suppresses human ovarian cancer cell metastasis potential through its effect on the expressions of PAI-1, E-cadherin and VEGF. Results from current work implicate Smad4 might suppress the invasion and metastasis of human ovarian tumor cells through a TGF-β/Smad-mediated pathway. [BMB reports 2010; 43(8): 554-560]