Grid-based methods for linearly equality constrained optimization problems

YAN FENG,XUESHENG ZHANG,LIYING LIU 한국전산응용수학회 2007 Journal of applied mathematics & informatics Vol.23 No.1

This paper describes a direct search method for a class of linearly constrained optimization problem. Through research we find it can be treated as an unconstrained optimization problem. And with the decrease of dimension of the variables need to be computed in the algorithms, the implementation of convergence to KKT points will be simplified to some extent. Convergence is shown under mild conditions which allow successive frames to be rotated, translated, and scaled relative to one another.

Impact of sorption functional media (SFM) from zeolite tailings on the removal of ammonia nitrogen in a biological aerated filter

Yan Feng,Yanzhen Yu,Liping Qiu,Yawen Yang,Zhigang Li,Miaowan Li,Lisha Fan,Yuzhong Guo 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.21 No.1

Haydite and sorption functional media (SFM),made of clinoptilolite tailings, were used as filter media forbiological aerated filter (BAF) to treat synthetic wastewater in parallel. The aim of this work was toevaluate impact of SFM on the removal of ammonia nitrogen in a biological aerated filter reactor underammonium nitrogen shock loads. It could be demonstrated that: (1) the BAF with SFMpresented higherammonia nitrogen removal efficiency than that with haydite; (2) during the phase of higher influentconcentrations SFMs were collecting ammonia nitrogen and can buffer ammonia nitrogen loads anddampen the effluent concentration of ammonia nitrogen; (3) when the influent concentration decreasesammonia nitrogen will desorb from the SFM and can be utilized by the nitrifying bacteria growing on theSFM. Therefore, with the SFM application existing BAF unites can be upgraded and the stability of theoperation process of BAF can be improved significantly.

A Weighted Recursive Averaging Approach for Noise Spectrum Estimation

Yan Feng 보안공학연구지원센터 2015 International Journal of Signal Processing, Image Vol.8 No.12

In the paper, we present a new noise spectrum estimation algorithm which is simple and effective for non-stationary background noise environments. The new proposed algorithm continuously updates the estimated noise by weighted noisy speech with a constant smoothing factor, the weighting factor is adjusted by an estimated signal-to-noise ratio (SNR), and the SNR is controlled by the local energy which be obtained by frequency smoothing of the noisy power spectrum in each frame. Objective experimental results and a subjective comparison show that the improved noise estimation algorithm when integrated in speech enhancement is preferred over the competitive noise estimation algorithms.

EGF Reverses Multi-drug Resistance via the p-ERK Pathway in HepG2/ADM and SMMC7721/ADM Hepatocellular Carcinoma Models

Yan, Feng,Bai, Li-Ping,Gao, Hua,Zhu, Chang-Ming,Lin, Li,Kang, Xiang-Peng Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.6

Aim: To investigate signaling pathways for reversal of EGF-mediated multi-drug resistance (MDR) in hepatocellular carcinoma (HCC) models. Materials and Methods: HCC MDR cell strain HepG2/adriamycin (ADM) and SMMC7721/ADM models were established using a method of exposure to medium with ADM between low and high concentration with gradually increasing concentration. Drug sensitivity and reversal of multi-drug resistance by EGF were determined and the cell cycle distribution and apoptosis were analyzed by flow cytometry. Phosphorylation of ERK1, ERK2, ERK5 and expression of Bim were detected by Western blotting. Results: The results showed that HepG2/ADM and SMMC7721/ADM cells were resistant not only to ADM, but also to multiple anticancer drugs. When used alone, EGF had no anti-tumor activity in HepG2/ADM and SMMC7721/ADM cells in vitro, while it increased the cytotoxicity of ADM. EGF induced cell apoptosis and G0/G1 phase cell cycle arrest in HepG2/ADM And SMMC7721/ADM cells, while enhancing activity of p-ERKs and up-regulated expression of BimEL. Conclusions: EGF might enhance the chemosensitivity of HepG2/ADM and SMMC7721/ADM cells via up-regulating p-ERKs and BimEL protein.

The characteristics and application of grain-slag media in a biological aerated filter (BAF)

Yan Feng,Liping Qiu,Jianwei Zhang,Longlong Gao,Yanzhen Yu 한국공업화학회 2012 Journal of Industrial and Engineering Chemistry Vol.18 No.3

Novel filter media-grain slag particles were prepared using waste material-grain slag, clay and poreforming material with a mass ratio of 3:2:1. Compared with haydite, grain-slag had higher total porosity,larger total surface area and lower bulk and apparent density. Tests of heavy metal elements in lixivium proved that grain-slag were safe for wastewater treatment. In order to ascertain the application of grainslag,grain-slag and haydite were applied as the media of biological aerated filters (BAF) to treat municipal wastewater in two lab scale upflow BAFs. The results showed that grain-slag reactor brought a relative superiority to haydite reactor in terms of chemical oxygen demand (CODcr) and ammonia nitrogen (NH3-N) removal at the conditions of water temperature ranging from 20 8C to 26 8C and DO 4.00 mg L1 when hydraulic retention time (HRT) ranging from 1 h to 5 h. In addition, the detection of the amount of hetero bacteria and nitrobacteria of two biological aerated filters in three HRTs also showed that grain-slag medium was more suitable to the attached growth of nitrobacteria, which is helpful to the improvement of nitrification performance in grain-slag BAF. Therefore, grain-slag application in BAF, as a novel process of treating wastes with wastes, provided a promising way in grain slag waste material utilization.

Knockdown of UHRF1 by Lentivirus-mediated shRNA Inhibits Ovarian Cancer Cell Growth

Yan, Feng,Shao, Li-Jia,Hu, Xiao-Ya Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.4

Human UHRF1 (ubiquitin-like PHD and RING finger domain-containing 1) has been reported to be over-expressed in many cancers, but its role in ovarian cancer remains elusive. Here, we determined whether knockdown of UHRF1 by lentivirus-mediated shRNA could inhibit ovarian cancer cell growth. Lentivirus-mediated short hairpin RNAs (lv-shRNAs-UHRF1) were designed to trigger the gene silencing RNA interference (RNAi) pathway. The efficiency of lentivirus-mediated shRNA infection into HO-8910 and HO-8910 PM cells was determined using fluorescence microscopy to observe lentivirus-mediated GFP expression and was confirmed to be over 80 percent. UHRF1 expression in infected HO-8910 and HO-8910 PM was evaluated by real-time PCR and Western blot analysis. The Cell Counting Kit-8 (CCK-8) assay was used to measure cell viability; flow cytometry and Hoechst 33342 assay was applied to measure cell cycle arrest and apoptosis. Cell invasion was assessed using transwell chambers. Our results demonstrated that the loss of UHRF1 promoted HO-8910 and HO-8910 PM cell apoptosis, while inhibiting cell proliferation. In addition, UHRF1 knockdown significantly inhibited the invasion of human ovarian cancer cells. In the present study, we also showed that depleting HO-8910 cells of UHRF1 caused activation of the DNA damage response pathway, with the cell cycle arrested in G2/M-phase. The DNA damage response in cells depleted of UHRF1 was illustrated by phosphorylation of CHK (checkpoint kinase) 2 on Thr68, phosphorylation of CDC25 (cell division control 25) on Ser 216 and phosphorylation of CDK1 (cyclin-dependent kinase 1) on Tyr 15.

Operator-based Robust Nonlinear Optimal Vibration Control for an Lshaped Arm Driven by Linear Pulse Motor

Yanfeng Wu,Mingcong Deng 제어·로봇·시스템학회 2017 International Journal of Control, Automation, and Vol.15 No.5

An L-shaped arm driven by a linear pulse motor is considered in this paper, an operator-based robustnonlinear control approach is proposed to reduce the vibration of the arm. First, by separating the arm into twoparts, its vibration dynamics is modelled based on Euler-Bernoulli beam theory. Second, by using operator-basedrobust right coprime factorization approach, two control schemes are designed, one for controlling the linear pulsemotor move to the desired destination and reducing the vibration of the arm with optimal trajectory, another oneis to control vibration of the arm by using a piezoelectric actuator, where a tracking compensator is designed tocompensate the hysteresis of the piezoelectric actuator and make the arm vibration track to the reference values. Finally, simulation results are demonstrated to verify the effectiveness of the proposed control scheme.

Incremental Optimization of Hub and Spoke Network under Changes of Spokes’ Number and Flow

Yanfeng Wang,Youfang Huang 보안공학연구지원센터 2016 International Journal of Hybrid Information Techno Vol.9 No.1

Hub and spoke network has been widely used in air transport, road freight, shipping network and urban distribution areas as part of the strategic decisions, which may have a profound effect on the future of enterprises. In view of the existing network structure, as time goes on, the number of spokes and the flow change because of different sources of uncertainty. Hence, the incremental optimization of the capacitated single-allocation hub and spoke network problem is considered in this paper, and the decisions to be made to cope with change comprise (i) whether new hubs need to be setup and their selection, (ii) whether the capacity levels of original hubs need to be adjusted, and their new capacity levels, (iii) whether the original hubs need to be closed, (iv) the new allocation of the spoke nodes to the hubs, (v) the flow distribution through the sub network defined by all the hubs. The objective is to minimize the total cost, which includes the setup costs for the new hubs, the closure costs and the adjustment costs for the original hubs as well as the flow routing costs. Two mixed-integer linear programming formulations are proposed and analyzed for this problem. A set of computational tests are performed, and we analyze the changes in the solutions driven by the number of spokes and the flow. The tests also allow an analysis to consider the effect of variation in parameters on the network.

MiR-212 Attenuates MPP+-Induced Neuronal Damage by Targeting KLF4 in SH-SY5Y Cells

Yanfeng Song,Ying Liu,Xiaowei Chen 연세대학교의과대학 2018 Yonsei medical journal Vol.59 No.3

Purpose: Parkinson’s disease (PD) is a common age-dependent neurodegenerative disease. MiR-212 has been demonstrated toexert protective effects in several neurological disorders. The present study aimed to investigate the role and underlying molecularmechanism of miR-212 in PD. Materials and Methods: 1-methyl-4-phenylpyridinium (MPP+)-induced SH-SY5Y cells were applied as a PD model in vitro. RTqPCRwas used to measure the expression of miR-212 and Kruppel-like factor 4 (KLF4) mRNA. Western blot analysis was performedto detect the protein levels of KLF4, Notch1 and Jagged1. Cell viability and apoptosis were determined by the Cell CountingKit-8 and flow cytometry, respectively. Quantitative analysis of caspase-3 activity, lactate dehydrogenase (LDH), reactiveoxygen species (ROS), superoxide dismutase (SOD), tumor necrosis factor-α (TNF-α), and interleukin-1 beta (IL-1β) was conductedwith corresponding ELISA kits. Dual-luciferase reporter assay was employed to evaluate the relationship between miR-212 and KLF4. Results: MiR-212 was downregulated in MPP+-induced SH-SY5Y cells. Also, miR-212 alleviated MPP+-induced SH-SY5Y cell damage,embodied by increased cell viability, decreased caspase-3 activity, LDH release, ROS production, TNF-α, and IL-1β expression,as well as elevated SOD levels. KLF4 was a direct target of miR-212, and miR-212 repressed KLF4 expression in a post-transcriptionalmanner. Moreover, miR-212-mediated protection effects were abated following KLF4 expression restoration in MPP+-induced SH-SY5Y cells, represented as lowered cell viability and enhanced apoptotic rate. Furthermore, Notch signaling wasinvolved in the regulation of miR-212/KLF4 axis in MPP+-induced SH-SY5Y cells. Conclusion: miR-212 might attenuate MPP+-induced neuronal damage by regulating KLF4/Notch signaling pathway in SH-SY5Ycells, a promising target for PD therapy.

Investigation on quasi-static and dynamic mechanical properties of disc springs considering asymmetric frictional boundary

Yanfeng Zhou,Dan Wang,Jianyuan He,Weifang Chen,Rupeng Zhu 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.11

Systematic experimental studies of disc springs are sparse. In this paper, quasistatic and dynamic compression experiments are performed on a single disc spring under both symmetric and asymmetric frictional conditions for different series of disc springs. On this basis, multiple disc springs stacked in parallel are also investigated. The full-range load-displacement curves of disc springs under quasi-static and dynamic compression are obtained and compared with the theoretical values, and the limitations of the existing analytical solutions are pointed out. The analysis revealed that frictional conditions of contact boundaries greatly affect the damping of disc springs. As the compression frequency increases, the damping of the disc spring gradually increases and finally remains stable. When the disc springs are stacked in parallel, the stiffness relationship can be approximated as conforming to the law of parallel connection, but the damping increases significantly due to the introduction of friction between internal contact surfaces.