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      • KCI등재

        Real-Time Repairable Interpolation Scheme for CNC Tool Path Processing

        Wei Fan,Chen-Han Lee,Ji-Hong Chen 한국정밀공학회 2016 International Journal of Precision Engineering and Vol.17 No.12

        G01 trajectory is widely-adopted for CNC machining. The piecewise linear trajectory is geometrically discontinuous, bringing about drastic fluctuation of feedrate and acceleration, and causing low machining efficiency and quality. Many methods of trajectory smoothing are developed and applied in CNC system. However some shortcomings exist when these methods were applied in CNC machining. In the existing methods, the following requirements are not satisfied simultaneously: not less than G2 continuity, confined chord error, shape preservation, interpolating G01 points, spatial applicability, real-time performance of algorithm, free geometric form. Considering various requirements of CNC machining, this work develops an interpolation scheme with local repairing function to deal with the possible shape deficiencies of trajectory. The resulting tool path has G2 continuity and is optimized in bending energy under shape-preserving and chord error constraints. Combining with jerk-limited feedrate scheduling, a real-time tool path processing strategy is developed. The simulation demonstrates the proposed method eliminates shape deficiencies, and has apparent advantage in the reduction of contour error, curvature, bending energy and machining time, compared with Zhao’s and Fan’s methods. The experiment demonstrates the advantages of the proposed algorithm in improving the quality of machined surface and machining efficiency, compared with previous methods.

      • Hypermethylation and Clinicopathological Significance of RASAL1 Gene in Gastric Cancer

        Chen, Hong,Pan, Ying,Cheng, Zheng-Yuan,Wang, Zhi,Liu, Yang,Zhao, Zhu-Jiang,Fan, Hong Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.11

        Background: Recent studies have suggested that expression of the RAS protein activator like-1 gene (RASAL1) is decreased in gastric carcinoma tissues and cell lines, indicated a role in tumorigenesis and development of gastric cancer. Reduced expression of RASAL1 could result in aberrant increase of activity of RAS signaling pathways in cancer cells. However, the exact mechanism which induces down-regulation of the RASAL1 gene remains unclear. This study aimed to determine the methylation status and regulation of RASAL1 in gastric cancer. Materials and Methods: Using the methylation-specific polymerase chain reaction (MSP), the methylation status of CpG islands in the RASAL1 promoter in gastric cancers and paired adjacent non-cancerous tissues from 40 patients was assessed and its clinicopathological significance was analyzed. The methylation status of RASAL1 in gastric cancer lines MKN-28, SGC-790l, BGC-823, as well as in normal gastric epithelial cell line GES-l was also determined after treatment with a DNA methyltransferase inhibitor, 5-aza-2'-doexycytidine (5-Aza-CdR). RAS activity (GAS-GTP) was assessed through a pull-down method, while protein levels of ERK1/2, a downstream molecule of RAS signaling pathways, were determined by Western blotting. Results: The frequencies of RASAL1 promoter methylation in gastric cancer and paired adjacent non-cancerous tissues were 70% (28/40) and 30% (12/40) respectively (P<0.05). There were significantly correlations between RASAL1 promoter methylation with tumor differentiation, tumor size, invasive depth and lymph node metastasis in patients with gastric cancer (all P<0.05), but no correlation was found for age or gender. Promoter hypermethylation of the RASAL1 gene was detected in MKN-28, SGC-790l and BGC-823 cancer cells, but not in the normal gastric epithelial cell line GES-1. Elevated expression of the RASAL1 protein, a decreased RAS-GTP and p-ERK1/2 protein were detected in three gastric cancer cell lines after treatment with 5-Aza-CdR. Conclusions: Aberrant hypermethylation of the RASAL1 gene promoter frequently occurs in gastric cancer tissues and cells. In addition, the demethylating agent 5-Aza-CdR can reverse the hypermethylation of RASAL1 gene and up-regulate the expression of RASAL1 significantly in gastric cancer cells in vivo. Our study suggests that RASAL1 promoter methylation may have a certain relationship with the reduced RASAL1 expression in gastric cancer.

      • KCI등재

        Ginsenoside Ro, an oleanolic saponin of Panax ginseng, exerts antiinflammatory effect by direct inhibiting toll like receptor 4 signaling pathway

        Hong-Lin Xu,Guang-Hong Chen,Yu-Ting Wu,Ling-Peng Xie,Zhang-Bin Tan,Bin Liu,Hui-Jie Fan,Hong-Mei Chen,Gui-Qiong Huang,Min Liu,Ying-Chun Zhou 고려인삼학회 2022 Journal of Ginseng Research Vol.46 No.1

        Background: Panax ginseng Meyer (P. ginseng), a herb distributed in Korea, China and Japan, exerts benefits on diverse inflammatory conditions. However, the underlying mechanism and active ingredients remains largely unclear. Herein, we aimed to explore the active ingredients of P. ginseng against inflammation and elucidate underlying mechanisms. Methods: Inflammation model was constructed by lipopolysaccharide (LPS) in C57BL/6 mice and RAW264.7 macrophages. Molecular docking, molecular dynamics, surface plasmon resonance imaging (SPRi) and immunofluorescence were utilized to predict active component. Results: P. ginseng significantly inhibited LPS-induced lung injury and the expression of proinflammatory factors, including TNF-a, IL-6 and IL-1b. Additionally, P. ginseng blocked fluorescence-labeled LPS (LPS488) binding to the membranes of RAW264.7 macrophages, the phosphorylation of nuclear factor-kB (NF-kB) and mitogen-activated protein kinases (MAPKs). Furthermore, molecular docking demonstrated that ginsenoside Ro (GRo) docked into the LPS binding site of toll like receptor 4 (TLR4)/myeloid differentiation factor 2 (MD2) complex. Molecular dynamic simulations showed that the MD2-GRo binding conformation was stable. SPRi demonstrated an excellent interaction between TLR4/MD2 complex and GRo (KD value of 1.16 × 10<SUP>-9</SUP> M). GRo significantly inhibited LPS488 binding to cell membranes. Further studies showed that GRo markedly suppressed LPS-triggered lung injury, the transcription and secretion levels of TNF-α, IL-6 and IL-1β. Moreover, the phosphorylation of NF-kB and MAPKs as well as the p65 subunit nuclear translocation were inhibited by GRo dose-dependently. Conclusion: Our results suggest that GRo exerts anti-inflammation actions by direct inhibition of TLR4 signaling pathway.

      • SCIESCOPUSKCI등재
      • Resveratrol Inhibits Oesophageal Adenocarcinoma Cell Proliferation via AMP-activated Protein Kinase Signaling

        Fan, Guang-Hua,Wang, Zhong-Ming,Yang, Xi,Xu, Li-Ping,Qin, Qin,Zhang, Chi,Ma, Jian-Xin,Cheng, Hong-Yan,Sun, Xin-Chen Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.2

        Resveratrol has been examined in several model systems for potential effects against cancer. Adenosine monophosphate-activated protein kinase (AMPK) is reported to suppress proliferation in most eukaryocyte cells. Whether resveratrol via AMPK inhibits proliferation of oesophageal adenocarcinoma cells (OAC) is unknown. The aim of this study was to determine the roles of AMPK in the protective effects of resveratrol in OAC proliferation and to elucidate the underlying mechanisms. Treatment of cultured OAC derived from human subjects or cell lines with resveratrol resulted in decreased cell proliferation. Further, inhibition of AMPK by pharmacological reagent or genetical approach abolished resveratrol-suppressed OAC proliferation, reduced the level of $p27^{Kip1}$, a cyclin-dependent kinase inhibitor, and increased the levels of S-phase kinase-associated protein 2 (Skp2) of $p27^{Kip1}$-E3 ubiquitin ligase and 26S proteasome activity reduced by resveratrol. Furthermore, gene silencing of $p27^{Kip1}$ reversed resveratrol-suppressed OAC proliferation. In conclusion, these findings indicate that resveratrol inhibits Skp2-mediated ubiquitylation and 26S proteasome-dependent degradation of $p27^{Kip1}$ via AMPK activation to suppress OAC proliferation.

      • KCI등재후보

        Icefex: Protocol Format Extraction from IL-based Concolic Execution

        ( Fan Pan ),( Li-fa Wu ),( Zheng Hong ),( Hua-bo Li ),( Hai-guang Lai ),( Chen-hui Zheng ) 한국인터넷정보학회 2013 KSII Transactions on Internet and Information Syst Vol.7 No.3

        Protocol reverse engineering is useful for many security applications, including intelligent fuzzing, intrusion detection and fingerprint generation. Since manual reverse engineering is a time-consuming and tedious process, a number of automatic techniques have been proposed. However, the accuracy of these techniques is limited due to the complexity of binary instructions, and the derived formats have missed constraints that are critical for security applications. In this paper, we propose a new approach for protocol format extraction. Our approach reasons about only the evaluation behavior of a program on the input message from concolic execution, and enables field identification and constraint inference with high accuracy. Moreover, it performs binary analysis with low complexity by reducing modern instruction sets to BIL, a small, well-specified and architecture-independent language. We have implemented our approach into a system called Icefex and evaluated it over real-world implementations of DNS, eDonkey, FTP, HTTP and McAfee ePO protocols. Experimental results show that our approach is more accurate and effective at extracting protocol formats than other approaches.

      • Expression and Prognostic Role of MEKK3 and pERK in Patients with Renal Clear Cell Carcinoma

        Chen, Qi,Lu, Hong-sheng,Gan, Mei-fu,Chen, Lan-xi,He, Kai,Fan, Guang-min,Cao, Xue-quan Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.6

        Mitogen-activated protein kinase/extracellular signal-regulated kinase kinase kinase 3 (MEKK3) is an important serine/threonine protein kinase and a member of the MAPK family. MEKK3 can effectively activate the MEK/ERK signaling pathway and promote an autocrine growth loop critical for tumor genesis, cell proliferation, terminal differentiation, apoptosis and survival. To explore the relationship between MEKK3 and cell apoptosis, clinicopathology and prognosis, we characterize the expression of MEKK3, pERK and FoxP3 in the renal clear cell carcinoma (RCCC). Protein expression was detected by tissue microarray and immunochemistry in 46 cases of RCCC and 28 control cases. Expression levels of CD3+,CD3+CD4+,CD3+CD8+,CD4+CD25+, CD4+CD25+ FoxP3+ were assessed by flow cytometry and analyzed for their association with pathological factors, correlation and prognosis in RCCC. Expression of MEKK3, pERK and FoxP3 was significantly up-regulated in RCCC as compared to control levels (p<0.01), associated with pathological grade (p<0.05)and clinical stage (p<0.05). CD4+CD25+ Foxp3+ Treg cells were also significantly increased in RCCC patients (p<0.05). Cox multivariate regression analysis showed that MEKK3, pERK expression and patholigical stage were independent prognostic factors in patients with RCCC (p<0.05). MEKK3 can be used as an important marker of early diagnosis and prognostic evaluation in RCCC. It may be associated with imbalance of anti-tumor immunity and overexpression of pERK. Expression of MEKK3 and pERK are significantly increased in RCCC, with protein expression and clinical stage acting as independent prognostic factors.

      • KCI등재

        Fault diagnosis of rotating machinery based on kernel density estimation and Kullback-Leibler divergence

        Fan Zhang,Yu Liu,Chujie Chen,Yanfeng Li,Hong-Zhong Huang 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.11

        Based on kernel density estimation (KDE) and Kullback-Leibler divergence (KLID), a new data-driven fault diagnosis method is proposedfrom a statistical perspective. The ensemble empirical mode decomposition (EEMD) together with the Hilbert transform is employedto extract 95 time- and frequency-domain features from raw and processed signals. The distance-based evaluation approach isused to select a subset of fault-sensitive features by removing the irrelevant features. By utilizing the KDE, the statistical distribution ofselected features can be readily estimated without assuming any parametric family of distributions; whereas the KLID is able to quantifythe discrepancy between two probability distributions of a selected feature before and after adding a testing sample. An integrated Kullback-Leibler divergence, which aggregates the KLID of all the selected features, is introduced to discriminate various faultmodes/damage levels. The effectiveness of the proposed method is demonstrated via the case studies of fault diagnosis for bevel gearsand rolling element bearings, respectively. The observations from the case studies show that the proposed method outperforms the supportvector machine (SVM)-based and neural network-based fault diagnosis methods in terms of classification accuracy. Additionally,the influences of the number of selected features and the training sample size on the classification performance are examined by a set ofcomparative studies.

      • KCI등재

        Temporal distribution, influencing factors and pollution sources of urban ambient air quality in Nanchong, China

        Hong Zhou,Youping Li,Huifang Liu,Zhongyu Fan,Jie Xia,Shanli Chen,Yuxiang Zheng,Xiaocui Chen 대한환경공학회 2015 Environmental Engineering Research Vol.20 No.3

        The PM10, SO₂ and NO₂ mass concentrations were obtained over five years from monitoring stations across Nanchong, a southwest city in China. Changes in urban air quality over time, as well as the factors influencing that change, were evaluated based on air pollutant concentrations, the Air Pollution Index (API), and the Comprehensive Pollution Index (P). The results showed that the total annual mean PM10, SO₂ and NO₂ concentrations over the five years studied were 61.1±1.1, 45.0±3.9 and 34.9±4.9 μg·m-3, respectively. The annual mean concentrations displayed a generally decreasing trend; lower than the annual mean second-level air quality limit. Meanwhile, the annual mean API values were in a small range of 52-53, the air quality levels were gradeⅡ, and P values were 1.06-1.21 less than the slight level (P ≤ 1.31). Total monthly mean PM10, SO₂, NO₂ concentrations, and API and P values were consistently higher in winter and spring than during autumn and summer. The results of a correlation analysis showed that temperature and pressure were the major meteorological factors influencing pollution levels. Pollution sources included industrial coal and straw burning, automobiles exhaust and road dust, fireworks, and dust storms.

      • SCIESCOPUSKCI등재

        Expression Analysis of miRNAs in Porcine Fetal Skeletal Muscle on Days 65 and 90 of Gestation

        Chen, Jian-hai,Wei, Wen-Juan,Xiao, Xiao,Zhu, Meng-Jin,Fan, Bin,Zhao, Shu-Hong Asian Australasian Association of Animal Productio 2008 Animal Bioscience Vol.21 No.7

        MiRNAs (microRNAs) are a class of small non-coding RNA molecules of ~21 nucleotides that down- regulate the expression of target genes at post-transcriptional level. In this study, we first accomplished a preliminary scan of miRNA expression using 65 and 90 day fetal pig skeletal muscle samples by microarray hybridization, and 34 miRNAs showed strong positive signals. Five of these miRNAs were selected for further investigation by real-time RT-PCR. The statistical analyses indicated that three miRNAs exhibited significant differential expression (p<0.05) during porcine muscle development from 65 to 90 days of gestation, e.g., miR-24 and miR-424 were down-regulated while miR-133a was up-regulated. Multi-tissue RT-PCR was performed to detect the expression patterns of the five miRNA precursors. The results showed that most of these precursor miRNAs were ubiquitously expressed in different porcine tissues.

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