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      • KCI등재

        RPTOR methylation in the peripheral blood and breast cancer in the Chinese population

        Yin Yifei,Lei Shuifang,Li Lixi,Yang Xiaoqin,Yin Qiming,Xu Tian,Zhou Wenjie,Li Hong,Gu Wanjian,Ma Fei,Yang Rongxi,Zhang Zhengdong 한국유전학회 2022 Genes & Genomics Vol.44 No.4

        Background: Altered regulatory-associated protein of mTOR, complex 1 (RPTOR) methylation levels in peripheral blood was originally discovered as breast cancer (BC)-associated risk factor in Caucasians. Objective: To explore the relationship between RPTOR methylation and BC in the Chinese population, we conducted two independent case-control studies. Methods: Peripheral blood samples were collected from a total of 333 sporadic BC cases and 378 healthy female controls for the DNA extraction and bisulfite-specific PCR amplification. Mass spectrometry was applied to quantitatively measure the levels of methylation. The logistic regression, Spearman's rank correlation, and Non-parametric tests were used for the statistical analyses. Results: In our study, we found an association between BC and RPTOR_CpG_4 hypomethylation in the general population (per-10% of methylation, OR 1.29, P = 0.012), and a weak association between BC and RPTOR_CpG_8 hypomethylation in the women with older age (per-10% of methylation, OR 2.34, P = 0.006). We also identified age as a confounder for the change of RPTOR methylation patterns, especially at RPTOR_CpG_4, which represented differential methylation comparing age groups especially in the BC cases (age < 50 years vs age ≥ 50 years by Mann-Whitney U test, P < 0.0001 for BC cases and P = 0.079 for controls). Conclusion: Our study validated the association between hypomethylation of RPTOR and BC risk in the Chinese population also with weak effect and mostly for postmenopausal women. In addition, our findings provided novel insight for the regulation of DNA methylation upon aging or the change of hormone levels.

      • KCI등재

        The Predictive Value of Magnetic Resonance Imaging-based Texture Analysis in Evaluating Histopathological Grades of Breast Phyllodes Tumor

        Yifei Mao,Zhongtang Xiong,Songxin Wu,Zhiqing Huang,Ruoxian Zhang,Yuqin He,Yuling Peng,Yang Ye,Tianfa Dong,Hui Mai 한국유방암학회 2022 Journal of breast cancer Vol.25 No.2

        Purpose: Knowing the distinction between benign and borderline/malignant phyllodes tumors (PTs) can help in the surgical treatment course. Herein, we investigated the value of magnetic resonance imaging-based texture analysis (MRI-TA) in differentiating between benign and borderline/malignant PTs. Methods: Forty-three women with 44 histologically proven PTs underwent breast MRI before surgery and were classified into benign (n = 26) and borderline/malignant groups (n = 18 [15 borderline, 3 malignant]). Clinical and routine MRI parameters (CRMP) and MRI-TA were used to distinguish benign from borderline/malignant PT. In total, 298 texture parameters were extracted from fat-suppression (FS) T2-weighted, FS unenhanced T1-weighted, and FS first-enhanced T1-weighted sequences. To evaluate the diagnostic performance, receiver operating characteristic curve analysis was performed for the K-nearest neighbor classifier trained with significantly different parameters of CRMP, MRI sequence-based TA, and the combination strategy. Results: Compared with benign PTs, borderline/malignant ones presented a higher local recurrence (p = 0.045); larger size (p < 0.001); different time-intensity curve pattern (p = 0.010); and higher frequency of strong lobulation (p = 0.024), septation enhancement (p = 0.048), cystic component (p = 0.023), and irregular cystic wall (p = 0.045). TA of FS T2- weighted images (0.86) showed a significantly higher area under the curve (AUC) than that of FS unenhanced T1-weighted (0.65, p = 0.010) or first-enhanced phase (0.72, p = 0.049) images. The texture parameters of FS T2-weighted sequences tended to have a higher AUC than CRMP (0.79, p = 0.404). Additionally, the combination strategy exhibited a similar AUC (0.89, p = 0.622) in comparison with the texture parameters of FS T2-weighted sequences. Conclusion: MRI-TA demonstrated good predictive performance for breast PT pathological grading and could provide surgical planning guidance. Clinical data and routine MRI features were also valuable for grading PTs.

      • Research on Close Shot Segmentation in Sports Video

        Yang Wang,Jingmeng Sun,Yifei Liu,Yueqiu Han 보안공학연구지원센터 2016 International Journal of Multimedia and Ubiquitous Vol.11 No.1

        The basketball segmentation in close shots is studied. According to the consistency of basketball color, color segmentation is implemented. Then with the help of steerable filters, the method detects image edges and the orientations of them. Finally, based on edges and their orientations, Hough transform is improved to get the circle center and the radius of basketball.

      • KCI등재

        Characteristic Model-based Adaptive Fault Tolerant Control for Four-motor Synchronization Systems Considering Actuator Failure

        Yang Gao,Jiali Ma,Qingwei Chen,Yifei Wu 제어·로봇·시스템학회 2021 International Journal of Control, Automation, and Vol.19 No.12

        This article proposes a characteristic model-based adaptive fault tolerant control scheme to deal with actuator failure in four-motor synchronization systems, which usually causes sudden inertia ratio change and backlash increase. Firstly, the characteristic modeling method is applied into servo system to obtain a simplified system model without losing high-order features. Also, this model could reflect real-time system status through three characteristic parameters. Secondly, a particle swarm optimization algorithm-based estimator is designed to identify characteristic parameters online. By this way, the characteristic model could react to inertia ratio changes quickly and eliminate its negative effect in signal tracking. Thirdly, an improved adaptive electric anti-backlash method is used to restrain backlash. Compared to regular anti-backlash technique, this adaptive one uses a neural networkbased fault detector to monitor motors and adjust bias current according to different actuator status, even when one motor breaks down. With these three steps combined, a fast terminal sliding mode controller is finally designed as fault tolerant controller and the stability of this closed-loop system is guaranteed by Lyapunov stability theorem. At last, the simulation and experiment results prove the effectiveness of the proposed control scheme in system control and fault tolerance.

      • KCI등재

        Characteristic Model-based Adaptive Control with Genetic Algorithm Estimators for Four-PMSM Synchronization System

        Yang Gao,Yifei Wu,Xiang Wang,Qingwei Chen 제어·로봇·시스템학회 2020 International Journal of Control, Automation, and Vol.18 No.6

        For four-PMSM synchronization systems, the complex structure, nonlinearities and uncertainties make accurate modeling and precise control difficult to realize. This article proposes an easily realized adaptive control scheme for four-PMSM synchronization system. This control scheme combines novel characteristic modeling, genetic algorithm and terminal sliding mode control together. Firstly, the four-PMSM synchronization system is described by characteristic model, which significantly simplifies system’s dynamic model without losing its highorder characteristics. Secondly, a genetic algorithm estimator is newly designed to estimate the real-time value of parameters in characteristic model, which is the key issue in obtaining an accurate system model. Thirdly, an adaptive discrete-time terminal sliding mode controller is proposed based on the characteristic model to enhance system robustness. Also, this controller can eliminate chattering effect when system is reversing. Then, the stability of the closed-loop system is proved by Lyapunov stability theorem. Finally, simulation and experiment results verify the adaptiveness and robustness of the proposed control scheme.

      • KCI등재

        New insights into the hydroquinone (HQ)–hexamethylenetetramine (HMTA) gel system for water shut-off treatment in high temperature reservoirs

        Yifei Liu,Caili Dai,Kai Wangb,Mingwei Zhao,Guang Zhao,Shuai Yang,Zhihu Yan,Qing You 한국공업화학회 2016 Journal of Industrial and Engineering Chemistry Vol.35 No.-

        Aiming at water shut-off in high temperature reservoirs, the hydroquinone (HQ)–hexamethylenetetra-mine (HMTA) gel system was studied. The gelation performance and effects of various parameters weresystematically evaluated. With increase of the concentrations and temperature, gelation time decreasesand gel strength increases. In addition, gelation rate and gel strength were enhanced on adding acid. Moreover, the gel system shows good salt tolerance. The thermal stability measurement indicates thatthe gel can maintain stability up to 140 8C. Uniformly distributed three-dimensional network structurewas formed in the gel. At last, the gelation mechanism was proposed, illuminating the detailed gelationprocess clearly.

      • SCIESCOPUSKCI등재

        Hair Growth Promoting Effects of 650 nm Red Light Stimulation on Human Hair Follicles and Study of Its Mechanisms via RNA Sequencing Transcriptome Analysis

        ( Kai Yang ),( Yulong Tang ),( Yanyun Ma ),( Qingmei Liu ),( Yan Huang ),( Yuting Zhang ),( Xiangguang Shi ),( Li Zhang ),( Yue Zhang ),( Ji’an Wang ),( Yifei Zhu ),( Wei Liu ),( Yimei Tan ),( Jinran 대한피부과학회 2021 Annals of Dermatology Vol.33 No.6

        Background: Androgenetic alopecia (AGA) leads to thinning of scalp hair and affects 60%~70% of the adult population worldwide. Developing more effective treatments and studying its mechanism are of great significance. Previous clinical studies have revealed that hair growth is stimulated by 650-nm red light. Objective: This study aimed to explore the effect and mechanism of 650-nm red light on the treatment of AGA by using ex vivo hair follicle culture. Methods: Human hair follicles were obtained from hair transplant patients with AGA. Hair follicles were cultured in Williams E medium and treated with or without 650-nm red light. Real-time RT-PCR and immunofluorescence staining were used to detect the expression level of genes and proteins in hair follicles, respectively. RNA-sequencing analysis was carried out to reveal the distinct gene signatures upon 650 nm treatment. Results: Low-level 650 nm red light promoted the proliferation of human hair follicles in the experimental cultured-tissue model. Consistently, 650 nm red light significantly delayed the transition of hair cycle from anagen to catagen in vitro. RNA-seq analysis and gene clustering for the differentially expressed genes suggests that leukocyte transendothelial migration, metabolism, adherens junction and other biological process maybe involved in stimulation of hair follicles by 650-nm red light treatment. Conclusion: The effect of 650-nm red light on ex vivo hair follicles and the transcriptome set which implicates the role of red light in promoting hair growth and reversing of miniaturization process of AGA were identified.

      • Investigation of a Novel IGCT Module for DC Circuit Breaker

        Qiang Yi,Yifei Wu,Yi Wu,Fei Yang,Zhihui Zhang,Chong Gao 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

        Power semiconductors for DC circuit breaker (DCCB) have attracted great attentions due to their fast and arc-less operation under full-range current-breaking. Since the robustness of Integrated Gate-Commutated Thyristor (IGCT) is the highest among all full-control power semiconductors, it becomes the perfect power semiconductor candidate for DC circuit breaker. In this paper, the principle and operation of hybrid circuit breaker are introduced. Technical analysis of full-control power semiconductor is conducted and IGCT is the best choice for HCB. Then, A novel power semiconductor circuit based on two IGCTs, diode-bridge, snubber-circuit and MOV is proposed and designed both topologically and structurally. The selection of full-control power semiconductor is discussed and fast recover diode must be used to ensure reliability. Furthermore, the internal current distribution is analyzed. Finally, a test of a single-stage IGCT module prototype demonstrates successful current-breaking at over 10kA and below 4kV, which is promising in the area of fault protection in future MVDC distribution system.

      • KCI등재

        Comparative transcriptome analysis of salt-sensitive and salt-tolerant maize reveals potential mechanisms to enhance salt resistance

        Mingquan Wang,Yufeng Wang,Yifei Zhang,Chunxia Li,Shichen Gong,Shuqin Yan,Guoliang Li,Guanghui Hu,Honglei Ren,Jianfei Yang,Tao Yu,Kejun Yang 한국유전학회 2019 Genes & Genomics Vol.41 No.7

        Background Salt stress is a devastating environmental stress that causes plant growth inhibition and yield reduction. Objective The identification of salt-tolerant genes brings hope for the generation of salinity-tolerant crop plants through molecular breeding. Methods In this study, one salt-sensitive and one salt-tolerant maize inbred line were screened from 242 maize inbred lines. Reactive oxygen species (ROS)-related enzyme activities were detected and salt-responsive comparative transcriptome analysis was performed for control and 220 mM NaCl treated maize leaves. Results Salt-tolerant maize inbred line (L87) showed higher ROS-related enzyme (SOD, POD, APX and CAT) activities and accumulated relatively lower levels of ROS under salt stress. Of the total DEGs, 1856 upregulated DEGs were specific to L87, including stress tolerance-related members of the 70kDa family of heat shock proteins (Hsp70s) and aquaporins. The DEGs involved in the abscisic acid (ABA), ethylene, jasmonic acid (JA) and salicylic acid (SA) signal transduction pathways may determine the difference in salt tolerance between the two varieties, especially one central component SnRK2, that positively regulates ABA signaling and was only upregulated in L87. Analysis of DEGs related to ROS scavenging showed that some peroxidase (POD), glutathione S-transferase (GST), catalase (CAT) and superoxide dismutase (SOD) genes specific to L87 probably enhanced its salt tolerance. The analysis of differentially expressed transcription factors (TFs) suggested that WRKY TFs could contribute to the difference in salt tolerance between the two maize lines. Conclusion Compared with Salt-sensitive maize inbred line (L29), L87 exhibits specific regulatory mechanisms related to salt tolerance, including plant hormone interactions, ROS scavenging and the regulation of TFs. Our study identifies new candidate genes that may regulate maize tolerance to salt stress and provides useful information for breeding maize with high salt resistance.

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