SOME RELATIONS ON PARAMETRIC LINEAR EULER SUMS

Weiguo Lu,Ce Xu,Jianing Zhou Korean Mathematical Society 2023 대한수학회보 Vol.60 No.4

Recently, Alzer and Choi [2] introduced and studied a set of the four linear Euler sums with parameters. These sums are parametric extensions of Flajolet and Salvy's four kinds of linear Euler sums [9]. In this paper, by using the method of residue computations, we will establish two explicit combined formulas involving two parametric linear Euler sums S⁺⁺_p,q (a, b) and S^+-_p,q (a, b) defined by Alzer and Choi, which can be expressed in terms of a linear combinations of products of trigonometric functions, digamma functions and Hurwitz zeta functions.

Longitudinal Dynamic End Effect of Single-Sided Linear Induction Motor for Medium–Low Speed Maglev

Wang Ying,Liu Xuelong,Lu Weiguo,Wen Tianqi,Yu Fan,Wu Qian 대한전기학회 2021 Journal of Electrical Engineering & Technology Vol.16 No.4

The Short Primary Single-sided Linear Induction Motor (SLIM) applied in medium–low maglev vehicle has end eff ect that will cause a signifi cant reduction of train thrust. This paper analyzes the relationship between the Longitudinal Dynamic End Eff ect (LDEE) and the speed of SLIM. It is concluded that LDEE increases with the motor speed. The LDEE at motor’s exit area is called tailing eff ect. We take advantage of the tailing eff ect between adjacent SLIMs to make the air-gap magnetic fi eld of these motors continuous by adjusting their intervals and excitation phase diff erence. The several SLIM on the same side of the vehicle is equivalent to a “whole motor” with overall one entry area and one exit area. This method can reduce the resistance of the whole vehicle running at high speed, which can provide a new solution for the design of high-speed SLIM applied in Maglev

High Step-Down Multiple-Output LED Driver with the Current Auto-Balance Characteristic

Quanming Luo,Binxin Zhu,Weiguo Lu,Luowei Zhou 전력전자학회 2012 JOURNAL OF POWER ELECTRONICS Vol.12 No.4

A high step-down multiple-output LED driver is proposed in this paper. Firstly, the derivation of the driver with dual-output is presented and its operation principle and steady state performance are analyzed in detail. Secondly, a high step-down N-channel LED driver is proposed and its current auto-balance characteristic and step-down ratio are analyzed. Finally, an experimental prototype is built and the experimental results are given. The theoretical analysis and experimental results show that the proposed driver has the following virtues: First, if load balancing is achieved, the voltage gain is 1/N that of a Buck driver, where N is the number of channels. Second, each output automatically has an equal output current, without requiring more current close-loop control circuits than a Buck driver. Last, the voltage stresses of the switches and diodes are lower than those of a Buck driver, meaning that lower voltage switches and diodes can be used, and a higher efficiency can be expected.

Direct Current Control Method Based On One Cycle Controller for Double-Frequency Buck Converters

Quanming Luo,Shubo Zhi,Weiguo Lu,Luowei Zhou 전력전자학회 2012 JOURNAL OF POWER ELECTRONICS Vol.12 No.3

In this paper, a direct current control method based on a one-cycle controller (DCOCC) for double frequency buck converters (DF buck) is proposed. This control method can make the average current through the high frequency and low frequency inductors of a DF buck converter equal. This is similar to the average current control method. However, the design of the loop compensator is much easier when compared with the average current control. Since the average current though the high frequency and low frequency inductors is equivalent, the current stress of the high frequency switches and the switch losses are minimized. Therefore, the efficiency of the DF buck converter is improved. Firstly, the operation principle of DCOCC is described, then the small signal models of a one cycle controller and a DF buck converter are presented based on the state space average method. Eventually, a system block diagram of the DCOCC controlled DF buck is established and the compensator is designed. Finally, simulation and experiment results are given to verify the correction of the theory analysis.

High Step-Down Multiple-Output LED Driver with the Current Auto-Balance Characteristic

Luo, Quanming,Zhu, Binxin,Lu, Weiguo,Zhou, Luowei The Korean Institute of Power Electronics 2012 JOURNAL OF POWER ELECTRONICS Vol.12 No.4

A high step-down multiple-output LED driver is proposed in this paper. Firstly, the derivation of the driver with dual-output is presented and its operation principle and steady state performance are analyzed in detail. Secondly, a high step-down N-channel LED driver is proposed and its current auto-balance characteristic and step-down ratio are analyzed. Finally, an experimental prototype is built and the experimental results are given. The theoretical analysis and experimental results show that the proposed driver has the following virtues: First, if load balancing is achieved, the voltage gain is 1/N that of a Buck driver, where N is the number of channels. Second, each output automatically has an equal output current, without requiring more current close-loop control circuits than a Buck driver. Last, the voltage stresses of the switches and diodes are lower than those of a Buck driver, meaning that lower voltage switches and diodes can be used, and a higher efficiency can be expected.

Direct Current Control Method Based On One Cycle Controller for Double-Frequency Buck Converters

Luo, Quanming,Zhi, Shubo,Lu, Weiguo,Zhou, Luowei The Korean Institute of Power Electronics 2012 JOURNAL OF POWER ELECTRONICS Vol.12 No.3

In this paper, a direct current control method based on a one-cycle controller (DCOCC) for double frequency buck converters (DF buck) is proposed. This control method can make the average current through the high frequency and low frequency inductors of a DF buck converter equal. This is similar to the average current control method. However, the design of the loop compensator is much easier when compared with the average current control. Since the average current though the high frequency and low frequency inductors is equivalent, the current stress of the high frequency switches and the switch losses are minimized. Therefore, the efficiency of the DF buck converter is improved. Firstly, the operation principle of DCOCC is described, then the small signal models of a one cycle controller and a DF buck converter are presented based on the state space average method. Eventually, a system block diagram of the DCOCC controlled DF buck is established and the compensator is designed. Finally, simulation and experiment results are given to verify the correction of the theory analysis.

SURF4 maintains stem-like properties via BIRC3 in ovarian cancer cells

Yongfang Yue,Lili Xia,Shanshan Xu,Conghui Wang,Xinyu Wang,Weiguo Lu,Xing Xie 대한부인종양학회 2020 Journal of Gynecologic Oncology Vol.31 No.4

Objective: As cancer stem cells (CSCs) are considered as the origin of tumor development,recurrence, and drug resistance, we aimed to explore the mechanism related to modulatingstemness in CSCs, thus facilitating to search for new therapeutic strategy for ovarian cancer. Methods: In this study, ovarian cancer stem cells (OCSCs) induced from cell line 3AOand A2780 were enriched in serum-free medium (SFM). The effect of SURF4 on CSC-likeproperties was evaluated by sphere-forming assays, re-differentiation assays, quantitativereal-time polymerase chain reaction, flow cytometry, Western blotting, cell viability assaysand in vivo xenograft experiments. The downstream molecule participating in SURF4maintaining stemness was screened by RNA-sequencing and identified by the experiments ofgene function. Results: SURF4 was upregulated expressed in OCSCs. Knockdown of SURF4 reduced theexpression of the related stem markers (SOX2 and c-MYC), inhibited self-renewal ability,and improved the sensitivity to chemotherapeutic drugs (paclitaxel and cisplatin) in OCSCs. SURF4 knockdown also inhibited tumorigenesis in nonobese diabetic/severe combinedimmunodeficiency mice. BIRC3 expression was controlled by SURF4, and BIRC3 showedthe similar effect as SURF4 did, and BIRC3 overexpression partially recovered stem-likeproperties abolished by SURF4 knockdown. Conclusion: Our findings suggest that SURF4 possesses the ability to maintain stemness ofOCSCs via BIRC3, and may serve as a potential target in stem cell-targeted therapy forovarian cancer.

The 16-year experience in treating low-risk gestational trophoblastic neoplasia patients with failed primary methotrexate chemotherapy

Xiaodong Wu,Jiale Qin,Tao Shen,Weidong Fei,Lili Chen,Xing Xie,Weiguo Lu 대한부인종양학회 2020 Journal of Gynecologic Oncology Vol.31 No.4

Objective: To assess the outcomes and toxic effects of 5-day actinomycin D (Act-D) salvagetherapy and to explore the predictors of Act-D resistance in patients with low-risk gestationaltrophoblastic neoplasia (GTN)who failed 5-day methotrexate (MTX) chemotherapy. Methods: This retrospective study analyzed patients with low-risk GTN administered Act-Dsalvage therapy after failing MTX chemotherapy at Women's Hospital, School of MedicineZhejiang University between January 2000 and December 2015. The clinical parameters ofthese patients were collected and analyzed. Results: The final analysis included 89 cases. Of these, 73 cases (82.02%) responded tosalvage Act-D. The remaining 16 resistant cases were switched to etoposide, MTX, Act-D/cyclophosphamide, and vincristine chemotherapy and achieved complete remission. Serumhuman chorionic gonadotrophin levels before Act-D salvage therapy (hCGAct-D)in the Act-D resistant cases were significantly higher than those in the Act-D responders (median 605 vs. 103 IU/L, p=0.009). However, the range of hCGAct-D values in Act-D responders was wider thanthat in Act-D-resistant cases (5.76–16,664 IU/L vs. 11.43–6,732 IU/L). Thus, assigning a generalcut-off value was difficult considering the individual setting. Except for 2 cases requiring othersalvage regimens due to Act-D toxicity, 97.80% of cases (89/91) tolerated the toxicity. During atleast 1-year follow-up, the survival rate was 100.00% and no case developed recurrence. Conclusion: Based on the good therapeutic effect and tolerable toxicity, we recommendAct-D salvage therapy for all patients with low-risk GTN who fail primary MTX chemotherapy. The higher serum hCG levels before Act-D salvage therapy may be associated with resistanceto this treatment.

The management of hydatidiform mole with lung nodule: a retrospective analysis in 53 patients

Xiao Li,Yaping Xu,Yuanyuan Liu,Xiaodong Cheng,Xinyu Wang,Weiguo Lu,Xing Xie 대한부인종양학회 2019 Journal of Gynecologic Oncology Vol.30 No.2

Objective: To investigate the significance of lung nodule in hydatidiform mole, we retrospectively compared the clinical outcomes of those patients treated with different strategies. Methods: The patients were divided into three groups: chemotherapy immediately once lung nodule was detected (group 1, n=17), delayed chemotherapy until human chorionic gonadotrophin (hCG) level met the diagnostic criteria for gestational trophoblastic neoplasia (GTN) (group 2, n=18), and hCG surveillance alone until hCG level was normalized spontaneously (group 3, n=18). The clinical parameters of these patients were collected and analyzed. Results: Totally 53 (4.0%) patients were included from 1,323 cases with molar pregnancy during past 16 years. Among them, the diameters of lung nodules were 0.3–2.5 cm. Chemotherapy cycles for achieving hCG normalization and the failure rate of first-line chemotherapy in group 1 were significantly increased than that in group 2 (5 vs. 3 cycles, p=0.000, 58.8% vs. 11.1%, p=0.005). The hCG level of all 18 cases in group 3 was normalized spontaneously within 6 months. Of those, lung nodules of 9 patients disappeared spontaneously, accounting for 25% (9/36) of patients who initially selected observation. The proportion of single nodule in group 3 was significantly higher than that in group 2 (10/18 vs. 2/18, p=0.012). Conclusion: Our results suggest that lung nodule alone is not an adequate indication of chemotherapy in molar pregnancy. hCG surveillance is safe for patients with lung nodule, especially with single nodule, as long as their hCG levels do not meet International Federation of Gynecology and Obstetrics diagnostic criteria for GTN.

Identification of miR-23a as a novel microRNA normalizer for relative quantification in human uterine cervical tissues

Shen, Yuanming,Li, Yang,Ye, Feng,Wang, Fenfen,Wan, Xiaoyun,Lu, Weiguo,Xie, Xing Korean Society for Biochemistry and Molecular Bion 2011 Experimental and molecular medicine Vol.43 No.6

Quantitative real-time RT-PCR (RT-qPCR) is being widely used in microRNA expression research. However, few reports detailed a robust identification and validation strategy for suitable reference genes for normalisation in microRNA RT-qPCR studies. The aim of this study was to identify the most stable reference gene(s) for quantification of microRNA expression analysis in uterine cervical tissues. A microarray was performed on 6 pairs of uterine cervical tissues to identify the candidate reference genes. The stability of candidate reference genes was assessed by RT-qPCR in 23 pairs of uterine cervical tissues. The identified most stable reference genes were further validated in other cohort of 108 clinical uterine cervical samples: (HR-HPV- normal, n = 21; HR-HPV+ normal, n = 19; cervical intraepithelial neoplasia [CIN], n = 47; cancer, n = 21), and the effects of normalizers on the relative quantity of target miR-424 were assessed. In the array experiment, miR-26a, miR-23a, miR-200c, let-7a, and miR-1979 were identified as candidate reference genes for subsequent validation. MiR-23a was identified as the most reliable reference gene followed by miR-191. The use of miR-23a and miR-191 to normalize expression data enabled detection of a significant deregulation of miR-424 between normal, CIN and cancer tissue. Our results suggested that miR-23a and miR-191 are the optimal reference microRNAs that can be used for normalization in profiling studies of cervical tissues; miR-23a is a novel microRNA normalizer.