A Control Strategy Based on Small Signal Model for Three-Phase to Single-Phase Matrix Converters

Chen, Si,Ge, Hongjuan,Zhang, Wenbin,Lu, Song The Korean Institute of Power Electronics 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.6

This paper presents a novel close-loop control scheme based on small signal modeling and weighted composite voltage feedback for a three-phase input and single-phase output Matrix Converter (3-1MC). A small non-polar capacitor is employed as the decoupling unit. The composite voltage weighted by the load voltage and the decoupling unit voltage is used as the feedback value for the voltage controller. Together with the current loop, the dual-loop control is implemented in the 3-1MC. In this paper, the weighted composite voltage expression is derived based on the sinusoidal pulse-width modulation (SPWM) strategy. The switch functions of the 3-1MC are deduced, and the average signal model and small signal model are built. Furthermore, the stability and dynamic performance of the 3-1MC are studied, and simulation and experiment studies are executed. The results show that the control method is effective and feasible. They also show that the design is reasonable and that the operating performance of the 3-1MC is good.

Relation between the local structure and solid solubility of the layered material LiMO2 (M=Co, Ni, Fe) in Li2MnO3

Chen Hou,Xiang Xiao,Yi-Ran Xing,Le-Le Yu,Yong-Heng Si,Han Lu,Yu-Juan Zhao 대한금속·재료학회 2022 ELECTRONIC MATERIALS LETTERS Vol.18 No.1

Although low solid solubility and activity of LiFeO2in xLi2MnO3·(1–x)LiFeO2 limit its practical application, it still has thepotential to become a new-generation cathode material without cobalt or nickel for Li-ion batteries. In order to understand theeffects of the local structures of different LiMO2(M = Co, Ni, Fe) layered materials on their solid solubility in Li2MnO3,partialdensities of states are calculated to determine the Jahn–Teller distortion in the layered cathode material, and the first-principlescalculation method based on density functional theory is used to optimize and compare the local structures of LiCoO2,LiNiO2,LiFeO2,LiMnO2,and Li2MnO3. The degrees of distortion of the transition metal–oxygen (M–O) and lithium–oxygen (Li–O)octahedra in the crystal structure of the material are evaluated. It is clear that the solid solubility of layered materials is relatedto the bond lengths and degrees of distortion of the M–O and Li–O octahedra. Among them, the similar bond length of LiNiO2and Li2MnO3and the high distortion of NiO6enhance the solid solubility of LiNiO2in Li2MnO3. Owing to the absence ofJahn–Teller distortion in LiFeO2and LiCoO2,the FeO6and CoO6octahedra are slightly distorted, thereby decreasing thesolid solubility of LiMO2(M = Fe, Co) in Li2MnO3. Understanding the relation between intra-octahedral distortion and solidsolubility provides simple and efficient evidence for comparing the solid solubilities of different LiMO2layered materials inthe Li2MnO3of Li-rich cathode materials. This study can be used as a reference for component design in Li-rich materials.

SLAMF7 is critical for phagocytosis of haematopoietic tumour cells via Mac-1 integrin

Chen, Jun,Zhong, Ming-Chao,Guo, Huaijian,Davidson, Dominique,Mishel, Sabrin,Lu, Yan,Rhee, Inmoo,Pé,rez-Quintero, Luis-Alberto,Zhang, Shaohua,Cruz-Munoz, Mario-Ernesto,Wu, Ning,Vinh, Donald C.,Si Nature Publishing Group 2017 Nature Vol. No.

<P>Cancer cells elude anti-tumour immunity through multiple mechanisms, including upregulated expression of ligands for inhibitory immune checkpoint receptors(1,2). Phagocytosis by macrophages plays a critical role in cancer control(3-6). Therapeutic blockade of signal regulatory protein (SIRP)-alpha, an inhibitory receptor on macrophages, or of its ligand CD47 expressed on tumour cells, improves tumour cell elimination in vitro and in vivo(7-10), suggesting that blockade of the SIRP alpha-CD47 checkpoint could be useful in treating human cancer(11-14). However, the prophagocytic receptor(s) responsible for tumour cell phagocytosis is(are) largely unknown. Here we find that macrophages are much more efficient at phagocytosis of haematopoietic tumour cells, compared with non-haematopoietic tumour cells, in response to SIRP alpha-CD47 blockade. Using a mouse lacking the signalling lymphocytic activation molecule (SLAM) family of homotypic haematopoietic cell-specific receptors, we determined that phagocytosis of haematopoietic tumour cells during SIRP alpha-CD47 blockade was strictly dependent on SLAM family receptors in vitro and in vivo. In both mouse and human cells, this function required a single SLAM family member, SLAMF7 (also known as CRACC, CS1, CD319), expressed on macrophages and tumour cell targets. In contrast to most SLAM receptor functions(15-17), SLAMF7-mediated phagocytosis was independent of signalling lymphocyte activation molecule-associated protein (SAP) adaptors. Instead, it depended on the ability of SLAMF7 to interact with integrin Mac-1 (refs 18-20) and utilize signals involving immunoreceptor tyrosine-based activation motifs(21,22). These findings elucidate the mechanism by which macrophages engulf and destroy haematopoietic tumour cells. They also reveal a novel SAP adaptor-independent function for a SLAM receptor. Lastly, they suggest that patients with tumours expressing SLAMF7 are more likely to respond to SIRP alpha-CD47 blockade therapy.</P>

A Control Strategy Based on Small Signal Model for Three-Phase to Single-Phase Matrix Converters

Si Chen,Hongjuan Ge,Wenbin Zhang,Song Lu 전력전자학회 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.6

This paper presents a novel close-loop control scheme based on small signal modeling and weighted composite voltage feedback for a three-phase input and single-phase output Matrix Converter (3-1MC). A small non-polar capacitor is employed as the decoupling unit. The composite voltage weighted by the load voltage and the decoupling unit voltage is used as the feedback value for the voltage controller. Together with the current loop, the dual-loop control is implemented in the 3-1MC. In this paper, the weighted composite voltage expression is derived based on the sinusoidal pulse-width modulation (SPWM) strategy. The switch functions of the 3-1MC are deduced, and the average signal model and small signal model are built. Furthermore, the stability and dynamic performance of the 3-1MC are studied, and simulation and experiment studies are executed. The results show that the control method is effective and feasible. They also show that the design is reasonable and that the operating performance of the 3-1MC is good.

Cone-beam computed tomographic evaluation of mandibular incisor alveolar bone changes for the intrusion arch technique: A retrospective cohort research

Lu Lin,Si Jiaping,Wang Zhikang,Chen Xiaoyan 대한치과교정학회 2024 대한치과교정학회지 Vol.54 No.2

Objective: Alveolar bone loss is a common adverse effect of intrusion treatment. Mandibular incisors are prone to dehiscence and fenestrations as they suffer from thinner alveolar bone thickness. Methods: Thirty skeletal class II patients treated with mandibular intrusion arch therapy were included in this study. Lateral cephalograms and cone-beam computed tomography images were taken before treatment (T1) and immediately after intrusion arch removal (T2) to evaluate the tooth displacement and the alveolar bone changes. Pearson’s and Spearman’s correlation was used to identify risk factors of alveolar bone loss during the intrusion treatment. Results: Deep overbite was successfully corrected (P < 0.05), accompanied by mandibular incisor proclination (P < 0.05). There were no statistically significant change in the true incisor intrusion (P > 0.05). The labial and lingual vertical alveolar bone levels showed a significant decrease (P < 0.05). The alveolar bone is thinning in the labial crestal area and lingual apical area (P < 0.05); accompanied by thickening in the labial apical area (P < 0.05). Proclined incisors, non-extraction treatment, and increased A point-nasion-B point (ANB) degree were positively correlated with alveolar bone loss. Conclusions: While the mandibular intrusion arch effectively corrected the deep overbite, it did cause some unwanted incisor labial tipping/flaring. During the intrusion treatment, the alveolar bone underwent corresponding changes, which was thinning in the labial crestal area and thickening in the labial apical area vice versa. And increased axis change of incisors, non-extraction treatment, and increased ANB were identified as risk factors for alveolar bone loss in patients with mandibular intrusion therapy.

Study on Interest Coordination Mechanism of Green Supply Chain Based on Dynamic Game

Lu fu-cai,Chen si-hua,He wei 보안공학연구지원센터 2015 International Journal of u- and e- Service, Scienc Vol.8 No.9

Green supply chain which aims at utilizing industrial waste is an effective form of circular economy and practical response to Chinese government’s call for establishment of conservation-oriented society. However, how to coordinate interests of members in green supply chain is a tricky but key problem for the smooth operation of green supply chain. Based on a multi-stage dynamic game model of green supply chain, this paper explores the interest relationship between government and manufacturers, that among manufacturers and that between manufacturers and retailers. Furthermore, this paper `proposes measures and conditions to ensure effective operation of green supply chain and intends to offer references for product pricing of green supply chain, coordination of members of green supply chain as well as governmental environment policy formulation.

Establishment of Paclitaxel-resistant Breast Cancer Cell Line and Nude Mice Models, and Underlying Multidrug Resistance Mechanisms in Vitro and in Vivo

Chen, Si-Ying,Hu, Sa-Sa,Dong, Qian,Cai, Jiang-Xia,Zhang, Wei-Peng,Sun, Jin-Yao,Wang, Tao-Tao,Xie, Jiao,He, Hai-Rong,Xing, Jian-Feng,Lu, Jun,Dong, Ya-Lin Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.10

Background: Breast cancer is a common malignant tumor which affects health of women and multidrug resistance (MDR) is one of the main factors leading to failure of chemotherapy. This study was conducted to establish paclitaxel-resistant breast cancer cell line and nude mice models to explore underlying mechanisms of MDR. Methods: The breast cancer drug-sensitive cell line MCF-7 (MCF-7/S) was exposed in stepwise escalating paclitaxel (TAX) to induce a resistant cell line MCF-7/TAX. Cell sensitivity to drugs and growth curves were measured by MTT assay. Changes of cell morphology and ultrastructure were examined by optical and electron microscopy. The cell cycle distribution was determined by flow cytometry. Furthermore, expression of proteins related to breast cancer occurrence and MDR was tested by immunocytochemistry. In Vivo, nude mice were injected with MCF-7/S and MCF-7/TAX cells and weights and tumor sizes were observed after paclitaxel treatment. In addition, proteins involved breast cancer and MDR were detected by immunohistochemistry. Results: Compared to MCF-7/S, MCF-7/TAX cells had a higher resistance to paclitaxel, cross-resistance and prolonged doubling time. Moreover, MCF-7/TAX showed obvious alterations of ultrastructure. Estrogen receptor (ER) expression was low in drug resistant cells and tumors while expression of human epidermal growth factor receptor 2 (HER2) and Ki-67 was up-regulated. P-glycoprotein (P-gp), lung resistance-related protein (LRP) and glutathione-S-transferase-${\pi}$ (GST-${\pi}$) involved in the MDR phenotype of resistant cells and tumors were all overexpressed. Conclusion: The underlying MDR mechanism of breast cancer may involve increased expression of P-gp, LRP and GST-${\pi}$.

OsSPL13 controls grain size in cultivated rice

Si, Lizhen,Chen, Jiaying,Huang, Xuehui,Gong, Hao,Luo, Jianghong,Hou, Qingqing,Zhou, Taoying,Lu, Tingting,Zhu, Jingjie,Shangguan, Yingying,Chen, Erwang,Gong, Chengxiang,Zhao, Qiang,Jing, Yufeng,Zhao, Y Nature Publishing Group, a division of Macmillan P 2016 Nature genetics Vol.48 No.4

<P>Although genetic diversity has a cardinal role in domestication, abundant natural allelic variations across the rice genome that cause agronomically important differences between diverse varieties have not been fully explored. Here we implement an approach integrating genome-wide association testing with functional analysis on grain size in a diverse rice population. We report that a major quantitative trait locus, GLW7, encoding the plant-specific transcription factor OsSPL13, positively regulates cell size in the grain hull, resulting in enhanced rice grain length and yield. We determine that a tandem-repeat sequence in the 5'UTR of OsSPL13 alters its expression by affecting transcription and translation and that high expression of OsSPL13 is associated with large grains in tropical japonica rice. Further analysis indicates that the large-grain allele of GLW7 in tropical japonica rice was introgressed from indica varieties under artificial selection. Our study demonstrates that new genes can be effectively identified on the basis of genome-wide association data.</P>

Glia maturation factor beta deficiency protects against diabetic osteoporosis by suppressing osteoclast hyperactivity

Shi Si,Gu Huijie,Xu Jinyuan,Sun Wan,Liu Caiyin,Zhu Tong,Wang Juan,Gao Furong,Zhang Jieping,Ou Qingjian,Jin Caixia,Xu Jingying,Chen Hao,Li Jiao,Xu Guotong,Tian Haibin,Lu Lixia 생화학분자생물학회 2023 Experimental and molecular medicine Vol.55 No.-

Excessive osteoclast activation, which depends on dramatic changes in actin dynamics, causes osteoporosis (OP). The molecular mechanism of osteoclast activation in OP related to type 1 diabetes (T1D) remains unclear. Glia maturation factor beta (GMFB) is considered a growth and differentiation factor for both glia and neurons. Here, we demonstrated that Gmfb deficiency effectively ameliorated the phenotype of T1D-OP in rats by inhibiting osteoclast hyperactivity. In vitro assays showed that GMFB participated in osteoclast activation rather than proliferation. Gmfb deficiency did not affect osteoclast sealing zone (SZ) formation but effectively decreased the SZ area by decreasing actin depolymerization. When GMFB was overexpressed in Gmfb-deficient osteoclasts, the size of the SZ area was enlarged in a dose-dependent manner. Moreover, decreased actin depolymerization led to a decrease in nuclear G-actin, which activated MKL1/SRF-dependent gene transcription. We found that pro-osteoclastogenic factors (Mmp9 and Mmp14) were downregulated, while anti-osteoclastogenic factors (Cftr and Fhl2) were upregulated in Gmfb KO osteoclasts. A GMFB inhibitor, DS-30, targeting the binding site of GMFB and Arp2/3, was obtained. Biocore analysis revealed a high affinity between DS-30 and GMFB in a dose-dependent manner. As expected, DS-30 strongly suppressed osteoclast hyperactivity in vivo and in vitro. In conclusion, our work identified a new therapeutic strategy for T1D-OP treatment. The discovery of GMFB inhibitors will contribute to translational research on T1D-OP.

Development of a multiplex qRT-PCR assay for detection of African swine fever virus, classical swine fever virus and porcine reproductive and respiratory syndrome virus

Yating Chen,Kaichuang Shi,Huixin Liu,Yanwen Yin,Jing Zhao,Feng Long,Wenjun Lu,Hongbin Si 대한수의학회 2021 Journal of Veterinary Science Vol.22 No.6

Background: African swine fever virus (ASFV), classical swine fever virus (CSFV), and porcine reproductive and respiratory syndrome virus (PRRSV) are still prevalent in many regions of China. Co-infections make it difficult to distinguish their clinical symptoms and pathological changes. Therefore, a rapid and specific method is needed for the differential detection of these pathogens. Objectives: The aim of this study was to develop a multiplex real-time quantitative reverse transcription polymerase chain reaction (multiplex qRT-PCR) for the simultaneous differential detection of ASFV, CSFV, and PRRSV. Methods: Three pairs of primers and TaqMan probes targeting the ASFV p72 gene, CSFV 5′ untranslated region, and PRRSV ORF7 gene were designed. After optimizing the reaction conditions, including the annealing temperature, primer concentration, and probe concentration, multiplex qRT-PCR for simultaneous and differential detection of ASFV, CSFV, and PRRSV was developed. Subsequently, 1,143 clinical samples were detected to verify the practicality of the assay. Results: The multiplex qRT-PCR assay could specifically and simultaneously detect the ASFV, CSFV, and PRRSV with a detection limit of 1.78 × 100 copies for the ASFV, CSFV, and PRRSV, but could not amplify the other major porcine viruses, such as pseudorabies virus, porcine circovirus type 1 (PCV1), PCV2, PCV3, foot-and-mouth disease virus, porcine parvovirus, atypical porcine pestivirus, and Senecavirus A. The assay had good repeatability with coefficients of variation of intra- and inter-assay of less than 1.2%. Finally, the assay was used to detect 1,143 clinical samples to evaluate its practicality in the field. The positive rates of ASFV, CSFV, and PRRSV were 25.63%, 9.36%, and 17.50%, respectively. The co-infection rates of ASFV+CSFV, ASFV+PRRSV, CSFV+PRRSV, and ASFV+CSFV+PRRSV were 2.45%, 2.36%, 1.57%, and 0.17%, respectively. Conclusions: The multiplex qRT-PCR developed in this study could provide a rapid, sensitive, specific diagnostic tool for the simultaneous and differential detection of ASFV, CSFV, and PRRSV.