Modified Modular Multilevel Converter with Submodule Voltage Fluctuation Suppression

Xin Huang,Kai Zhang,Jingbo Kan,Jian Xiong 전력전자학회 2017 JOURNAL OF POWER ELECTRONICS Vol.17 No.4

Modular multilevel converters (MMCs) have been receiving extensive research interest in high/medium-voltage applications due to its modularity, scalability, reliability, high-voltage capability, and excellent harmonic performance. Submodule capacitors are usually rather bulky because they have to withstand fundamental frequency voltage fluctuations. To reduce the capacitance of these capacitors, this study proposes a modified MMC with an active power decoupling circuit within each submodule. The modified submodule contains an auxiliary half bridge, with its capacitor split in two. Also, the midpoints of the half bridge and the split capacitors are connected by an inductor. With this modified submodule, the fundamental frequency voltage fluctuation can be suppressed to a great extent. The second-order voltage fluctuation, which is the second most significant component in submodule voltage fluctuations, is removed by the proper control of the second-order circulating current. Consequently, the submodule capacitance is significantly reduced. The viability and effectiveness of the proposed new MMC are confirmed by the simulation and experimental results. The proposed MMC is best suited for medium-voltage applications where power density is given a high priority.

The Solvent Distribution Effect on the Self-Assembly of Symmetric Triblock Copolymers during Solvent Vapor Annealing

Xiong, Shisheng,Li, Dongxue,Hur, Su-Mi,Craig, Gordon S. W.,Arges, Christopher G.,Qu, Xin-Ping,Nealey, Paul F. American Chemical Society 2018 Macromolecules Vol.51 No.18

<P>Using a combination of systematic experiments and Monte Carlo simulations, this report demonstrates that the distribution of neutral solvent has a strong impact on the quality and kinetics of the self-assembly of block copolymers in thin films. Both methyl ethyl ketone (MEK, a good solvent) and acetone (a relatively poor solvent) were used for the solvent vapor annealing (SVA) of thin films of poly(2-vinylpyridine)-<I>block</I>-polystyrene-<I>block</I>-poly(2-vinylpyridine) (VSV) triblock copolymer. Acetone, the poorer solvent, accumulated at the interface of the VSV domains, while MEK was distributed more uniformly throughout the VSV. As a result, acetone screened the interactions between the blocks of the copolymer more than MEK. Because MEK afforded less screening of the different blocks, solvent annealing with MEK led to self-assembly of lower molecular weight VSV triblock copolymers than was possible with acetone. Solvent annealing with MEK also led to slower self-assembly kinetics and smaller correlation lengths in the assembled pattern compared to solvent annealing with acetone. Finally, long-range ordered structures of low molecular weight VSV triblock copolymer on a chemical pattern via directed self-assembly was demonstrated with 6× density multiplication by annealing in MEK.</P> [FIG OMISSION]</BR>

Microarray Analysis of Long Non-coding RNA Expression Profile Associated with 5-Fluorouracil-Based Chemoradiation Resistance in Colorectal Cancer Cells

Xiong, Wei,Jiang, Yong-Xin,Ai, Yi-Qin,Liu, Shan,Wu, Xing-Rao,Cui, Jian-Guo,Qin, Ji-Yong,Liu, Yan,Xia, Yao-Xiong,Ju, Yun-He,He, Wen-Jie,Wang, Yong,Li, Yun-Fen,Hou, Yu,Wang, Li,Li, Wen-Hui Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.8

Background: Preoperative 5-fluorouracil (5-FU)-based chemoradiotherapy is a standard treatment for locally advanced colorectal cancer (CRC). However, CRC cells often develop chemoradiation resistance (CRR). Recent studies have shown that long non-coding RNA (lncRNA) plays critical roles in a myriad of biological processes and human diseases, as well as chemotherapy resistance. Since the roles of lncRNAs in 5-FU-based CRR in human CRC cells remain unknown, they were investigated in this study. Materials and Methods: A 5-FU-based concurrent CRR cell model was established using human CRC cell line HCT116. Microarray expression profiling of lncRNAs and mRNAs was undertaken in parental HCT116 and 5-FU-based CRR cell lines. Results: In total, 2,662 differentially expressed lncRNAs and 2,398 mRNAs were identified in 5-FU-based CRR HCT116 cells when compared with those in parental HCT116. Moreover, 6 lncRNAs and 6 mRNAs found to be differentially expressed were validated by quantitative real time PCR (qRT-PCR). Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis for the differentially expressed mRNAs indicated involvement of many, such as Jak-STAT, PI3K-Akt and NF-kappa B signaling pathways. To better understand the molecular basis of 5-FU-based CRR in CRC cells, correlated expression networks were constructed based on 8 intergenic lncRNAs and their nearby coding genes. Conclusions: Changes in lncRNA expression are involved in 5-FU-based CRR in CRC cells. These findings may provide novel insight for the prognosis and prediction of response to therapy in CRC patients.

Association between the severity of hypodontia and the characteristics of craniofacial morphology in a Chinese population: A cross-sectional study

Xin Xiong,Jiaqi Liu,Yange Wu,Chengxinyue Ye,Qinlanhui Zhang,Yufan Zhu,Wenke Yang,Jun Wang 대한치과교정학회 2023 대한치과교정학회지 Vol.53 No.3

Objective: To investigate craniofacial differences in individuals with hypodontia and explore the relationship between craniofacial features and the number of congenitally missing teeth. Methods: A cross-sectional study was conducted among 261 Chinese patients (males, 124; females, 137; age, 7–24 years), divided into four groups (without hypodontia: no teeth missing, mild: one or two missing teeth, moderate: three to five missing teeth, severe: six or more missing teeth) according to the number of congenitally missing teeth. Differences in cephalometric measurements among the groups were analyzed. Further, multivariate linear regression and smooth curve fitting were performed to evaluate the relationship between the number of congenitally missing teeth and the cephalometric measurements. Results: In patients with hypodontia, SNA, NA-AP, FH-NA, ANB, Wits, ANS-Me/N-Me, GoGn-SN, UL-EP, and LL-EP significantly decreased, while Pog-NB, AB-NP, N-ANS, and S-Go/N-Me significantly increased. In multivariate linear regression analysis, SNB, Pog-NB, and S-Go/N-Me were positively related to the number of congenitally missing teeth. In contrast, NA-AP, FH-NA, ANB, Wits, N-Me, ANS-Me, ANS-Me/N-Me, GoGn-SN, SGn-FH (Y-axis), UL-EP, and LL-EP were negatively related, with absolute values of regression coefficients ranging from 0.147 to 0.357. Further, NA-AP, Pog-NB, S-Go/N-Me, and GoGn-SN showed the same tendency in both sexes, whereas UL-EP and LL-EP were different. Conclusions: Compared with controls, patients with hypodontia tend toward a Class III skeletal relationship, reduced lower anterior face height, flatter mandibular plane, and more retrusive lips. The number of congenitally missing teeth had a greater effect on certain characteristics of craniofacial morphology in males than in females.

Estimation of damping induced by taut mooring lines

Xiong, Lingzhi,Lu, Wenyue,Li, Xin,Guo, Xiaoxian The Society of Naval Architects of Korea 2020 International Journal of Naval Architecture and Oc Vol.12 No.1

A moored floating structure may exhibit resonant motion responses to low-frequency excitations. Similar to the resonant responses of many vibration systems, the motion amplitude of a moored floating structure is significantly affected by the damping of the entire system. In such cases, the damping contributed by the mooring lines sometimes accounts for as much as 80% of the total damping. While the damping induced by catenary mooring lines is well-investigated, few studies have been conducted on the damping induced by taut mooring lines, especially one partly embedded in soil. The present study develops a simple but accurate model for estimating the damping contributed by mooring lines. A typical type of taut mooring line was used as the reference and the hydrodynamic drag force and soil resistance were taken into consideration. The proposed model was validated by comparing its predictions with those of a previously developed model and experimental measurements obtained by a physical model. Case studies and sensitivity studies were also conducted using the validated model. The damping induced by the soil resistance was found to be considerably smaller than the hydrodynamic damping. The superposition of the wave frequency motion on the low-frequency motion was also observed to significantly amplify the damping induced by the mooring lines.

A review on the properties and applications of chitosan, cellulose and deep eutectic solvent in green chemistry

Xin Xiong Chang,Nabisab Mujawar Mubarak,Shaukat Ali Mazari,Abdul Sattar Jatoi,Awais Ahmad,Mohammad Khalid,Rashmi Walvekar,E.C. Abdullah,Rama Rao Karri,M.T.H Siddiqui,Sabzoi Nizamuddin 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.104 No.-

The concept of green chemistry has attracted attention due to the green synthesis and ecofriendly natureof the compounds leading to the green and sustainable chemical industries and processes. Chitosan is anecofriendly material, which is biodegradable, non-toxic, and biocompatible. It has the potential to bemodified into biofilms for various applications such as biomedical, packaging, and pharmaceutical fields. Nevertheless, some poor properties of chitosan restrict its wide applications. The incorporation ofnanocellulose fillers into chitosan matrix can enhance the mechanical and thermal properties of chitosan. Cellulose nanomaterials can be achieved through chemical and mechanical modifications. The commontype of nanocellulose are cellulose nanofibers (CNFs), cellulose nano-whiskers (CNWs), tunicate CNCs (t-CNCs), algae cellulose particles (AC) and bacterial cellulose particles (BC). Nanocellulose are applied asthe reinforcement fillers in various polymer matrices such as polysaccharides, proteins, lipids, polylacticacid etc. Deep eutectic solvents (DES) are relatively novel green solvents, which can be applied in variousfields. DES are widely applied in metal processing, polymer processing and synthesis. Even though thereare not much studies available on DES for synthesis of nanocomposite films; however they are used aseco-friendly solvents in manufacturing processes. This study reviews the discovery, structure, propertiesof chitosan and cellulose, their derivatives and applications. In addition, the paper also discusses theproperties of DES and their applications.

Primary School Students` Understanding of Equation Structure and the Meaning of Equal Sign: A Chinese Sample Study

( Xin Rong Yang ),( Yu Jia Huo ),( Yan Xiong Yan ) 한국수학교육학회 2014 수학교육연구 Vol.18 No.4

This paper reports findings from a written assessment which was designed to investigate Chinese primary school students`` understanding of the equal sign and equation structure. The investigation included a sample of 110 Grade 3, 112 Grade 4, and 110 Grade 5 students from four schools in China. Significant differences were identified among the three grades and no gender differences were found. The majority of Grades 3 and 4 students were found to view the equal sign as a place indicator meaning "write the answer here" or "do something like computation", that is, holding an operational view of the equal sign. A part of Grade 5 students were found to be able to interpret the equal sign as meaning "the same as", that is, holding a relational view of the equal sign. In addition, even though it was difficult for Grade 3 students to recognize the underlying structure in arithmetic equation, quite a number of Grades 4 and 5 students were able to recognize the underlying structure on some tasks. Findings in this study suggest that Chinese primary school students demonstrate a relational understanding of the equal sign and a strong structural sense of equations in an earlier grade. Moreover, what found in the study support the argument that students`` understanding of the equal sign is influenced by the context in which the equal sign is presented.

Single-cell RNA sequencing reveals B cell–related molecular biomarkers for Alzheimer’s disease

Xiong Liu-Lin,Xue Lu-Lu,Du Ruo-Lan,Niu Rui-Ze,Chen Li,Chen Jie,Hu Qiao,Tan Ya-Xin,Shang Hui-Fang,Liu Jia,Yu Chang-Yin,Wang Ting-Hua 생화학분자생물학회 2021 Experimental and molecular medicine Vol.53 No.-

In recent years, biomarkers have been integrated into the diagnostic process and have become increasingly indispensable for obtaining knowledge of the neurodegenerative processes in Alzheimer’s disease (AD). Peripheral blood mononuclear cells (PBMCs) in human blood have been reported to participate in a variety of neurodegenerative activities. Here, a single-cell RNA sequencing analysis of PBMCs from 4 AD patients (2 in the early stage, 2 in the late stage) and 2 normal controls was performed to explore the differential cell subpopulations in PBMCs of AD patients. A significant decrease in B cells was detected in the blood of AD patients. Furthermore, we further examined PBMCs from 43 AD patients and 41 normal subjects by fluorescence activated cell sorting (FACS), and combined with correlation analysis, we found that the reduction in B cells was closely correlated with the patients’ Clinical Dementia Rating (CDR) scores. To confirm the role of B cells in AD progression, functional experiments were performed in early-stage AD mice in which fibrous plaques were beginning to appear; the results demonstrated that B cell depletion in the early stage of AD markedly accelerated and aggravated cognitive dysfunction and augmented the Aβ burden in AD mice. Importantly, the experiments revealed 18 genes that were specifically upregulated and 7 genes that were specifically downregulated in B cells as the disease progressed, and several of these genes exhibited close correlation with AD. These findings identified possible B cell-based AD severity, which are anticipated to be conducive to the clinical identification of AD progression.

Parecoxib: an Enhancer of Radiation Therapy for Colorectal Cancer

Xiong, Wei,Li, Wen-Hui,Jiang, Yong-Xin,Liu, Shan,Ai, Yi-Qin,Liu, Rong,Chang, Li,Zhang, Ming,Wang, Xiao-Li,Bai, Han,Wang, Hong,Zheng, Rui,Tan, Jing Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.2

Background: To study the effect of parecoxib, a novel cyclooxygenase-2 selective inhibitor, on the radiation response of colorectal cancer (CRC) cells and its underlying mechanisms. Materials and Methods: Both in vitro colony formation and apoptosis assays as well as in vivo mouse xenograft experiments were used to explore the radiosensitizing effects of parecoxib in human HCT116 and HT29 CRC cells. Results: Parecoxib sensitized CRC cells to radiation in vitro with a sensitivity enhancement ratio of 1.32 for HCT116 cells and 1.15 for HT29 cells at a surviving fraction of 0.37. This effect was partially attributable to enhanced apoptosis induction by parecoxib combined with radiation, as illustrated using an in vitro apoptosis assays. Parecoxib augmented the tumor response of HCT116 xenografts to radiation, achieving growth delay more than 20 days and an enhancement factor of 1.53. In accordance with the in vitro results, parecoxib combined with radiation resulted in less proliferation and more apoptosis in tumors than radiation alone. Radiation monotherapy decreased microvessel density (MVD) and microvessel intensity (MVI), but increased the hypoxia level in xenografts. Parecoxib did not affect MVD, but it increased MVI and attenuated hypoxia. Conclusions: Parecoxib can effectively enhance radiation sensitivity in CRC cells through direct effects on tumor cells and indirect effects on tumor vasculature.

Mortality of Urinary Tract Cancer in Inner Mongolia 2008-2012

Xin, Ke-Peng,Du, Mao-Lin,Li, Zhi-Jun,Li, Yun,Li, Wuyuntana,Su, Xiong,Sun, Juan Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.6

The aim of this study was to determine the mortality rate and burden of urinary tract cancers among residents of Inner Mongolia. We analyzed mortality data reported by the Death Registry System from 2008 to 2012. The rate of mortality due to urinary tract cancer was 2.04 per 100,000 person-years for the total population, 2.91 for men, and 1.11 for women. Therefore, the mortality rate for men was 2.62-fold the mortality rate for women, constituting a statistically significant difference (p<0.001). Over the period 2008 through 2012, the total potential years of life lost was 1388.1 person-years for men and 777.1 person-years for women, and the average years of life lost were 7.71 years per male decedent and 12.0 years per female decedent. Mortality due to urinary tract cancers is substantially greater among the elderly population. Further, the mortality rate associated with urinary tract cancers is greater for elderly men than it is for elderly women. Therefore, in Inner Mongolia, urinary tract cancers appear to pose a greater mortality risk for men than they do for women.