An Improved Variable Step Size MPPT Algorithm Based on INC

Zhi-rong Xu,Ping Yang,Dong-bao Zhou,Peng Li,Jin-yong Lei,Yuan-rui Chen 전력전자학회 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.2

In order to ensure that photovoltaic (PV) systems work at the maximum power point (MPP) and maximize the economic benefits, maximum power point tracking (MPPT) techniques are normally applied to these systems. One of the most widely applied MPPT methods is the incremental conductance (INC) method. However, the choice of the step size still remains controversial. This paper presents an improved variable step size INC MPPT algorithm that uses four different step sizes. This method has the advantages of INC but with the ability to validly adjust the step size to adapt to changes of the PV’s power curve. The presented algorithm also simultaneously achieves increased rapidity and accuracy when compared with the conventional fixed step size INC MPPT algorithm. In addition, the theoretical derivation and specific applications of the proposed algorithm are presented here. This method is validated by simulation and experimental results.

An Improved Variable Step Size MPPT Algorithm Based on INC

Xu, Zhi-Rong,Yang, Ping,Zhou, Dong-Bao,Li, Peng,Lei, Jin-Yong,Chen, Yuan-Rui The Korean Institute of Power Electronics 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.2

In order to ensure that photovoltaic (PV) systems work at the maximum power point (MPP) and maximize the economic benefits, maximum power point tracking (MPPT) techniques are normally applied to these systems. One of the most widely applied MPPT methods is the incremental conductance (INC) method. However, the choice of the step size still remains controversial. This paper presents an improved variable step size INC MPPT algorithm that uses four different step sizes. This method has the advantages of INC but with the ability to validly adjust the step size to adapt to changes of the PV's power curve. The presented algorithm also simultaneously achieves increased rapidity and accuracy when compared with the conventional fixed step size INC MPPT algorithm. In addition, the theoretical derivation and specific applications of the proposed algorithm are presented here. This method is validated by simulation and experimental results.

Salvianolic Acid B Reverses the Epithelial-to-mesenchymal Transition of HK-2 Cells that is Induced by Transforming Growth Factor-β

Rong-hua Pan,Feng-yan Xie,Hui-mei Chen,Li-zhi Xu,Xiao-chun Wu,Ling-ling Xu,Gang Yao 대한약학회 2011 Archives of Pharmacal Research Vol.34 No.3

Salvianolic acid B (Sal B) is the most abundant bioactive molecule from Radix Salviae Miltiorrhizae, and has recently been used for treating renal fibrosis in traditional Chinese medicine. Here we investigated the ability reversal of Sal B to reverse the transdifferentiation of human kidney proximal tubular epithelial cells that was induced by transforming growth factor-beta 1 (TGF-β1). The effects of Sal B on HK-2 cell morphology were observed by phase contrast microscopy, while alpha smooth muscle actin and E-cadherin were studied by immunocytochemistry and real-time reverse transcription polymerase chain reaction, respectively. Exposure of HK-2 cells to TGF-β1 for 72 h induced a complete conversion of the epithelial cells to myofibroblasts. When HK-2 cells were co-incubated with Sal B and TGF-β1 for a further 72 h, the morphology of myofibroblasts returned to that of proximal tubular epithelial cells,whereas the myofibroblast phenotype was maintained after exposure of cells to TGF-β1 for 144 h. Sal B reduced alpha smooth muscle actin levels and increased E-cadherin levels compared with their epithelial-to-mesenchymal transition controls. The reversal effect of Sal B was dose-dependent. That Sal B reverses the epithelial-to-mesenchymal transition in vitro suggests that it could possibly facilitate the repair of tubular epithelial structures and the regression of renal fibrosis in injured kidneys.

MLH1 Polymorphisms and Cancer risk: a Meta-analysis Based on 33 Case-control Studies

Xu, Jia-Li,Yin, Zhi-Qiang,Huang, Ming-De,Wang, Xie-Feng,Gao, Wen,Liu, Ling-Xiang,Wang, Rong-Sheng,Huang, Pu-Wen,Yin, Yong-Mei,Liu, Ping,Shu, Yong-Qian Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.3

Objective: Cumulative evidence suggests that MLH1, the key component in the mismatch pathway, plays an important role in human cancers. Two potential functional polymorphisms (-93G>A and I219V) of MLH1 have been implicated in cancer risk. The aim of this meta-analysis was to summarize the evidence for associations. Methods: Eligible studies were identified by searching the electronic literature PubMed, ScienceDirect and Embase databases for relevant reports and bibliographies. Studies were included if of case-control design investigating MLH1 polymorphisms (-93G>A and I219V) and cancer risk with sufficient raw data for analysis. Odds ratios (OR) and 95% confidence intervals (95% CI) were used to evaluate the strength of associations. Results: Our meta-analysis from 33 published case-control studies showed the variant A allele of -93G>A polymorphism to be associated with increased risk in all genetic models (AA vs. GG: OR = 1.22, 95% CI: 1.03-1.44), especially among non-Asians (AA vs. GG: OR = 1.28, 95% CI: 1.04-1.58). For the I219V polymorphism, however, there was no main effect associated with overall cancer risk in any genetic model. Conclusions: The meta-analysis suggested that the MLH1 -93G>A polymorphism may be a biomarker of cancer susceptibility. Large sample association studies and assessment of gene-to-gene as well as gene-to-environment interactions are required to confirm these findings.

Preparation of HMX by Catalytic Nitrolysis of DPT in AIL-N_2O_5-HNO_3 System

Zhi-yong He,Jun Luo,Chun-xu Lü,Ping Wang,Rong Xu,Jin-shan Li 대한화학회 2011 Bulletin of the Korean Chemical Society Vol.32 No.8

Direct nitrolysis of 3,7-dinitro-1,3,5,7-tetraazabicyclo[3,3,1]nonane (DPT) is a feasible way to synthesize HMX, and it has multiple practical applications. In this paper, a new nitrolysis process involving the use of an N_2O_5-HNO_3 system catalyzed by acidic ionic liquids (AILs) was developed. The results show that [Et_3NH]TsO was the best catalyst among the 28 AILs used and that HMX was formed at a higher yield of 61%, compared to 45% without any AIL. Moreover, with the addition of N_2O_5, the yield was further increased to a maximum value of 69%. The AILs were also efficiently recovered by simple extractions without any apparent loss of catalytic activity, even after five runs.

Clinical and Pathologic Features of Multifocal and Multicentric Breast Cancer in Chinese Women: A Retrospective Cohort Study

Mei-rong Zhou,Zhong-hua Tang,Jing Li,Jin-Hu Fan,Yi Pang,Hong-jian Yang,Shan Zheng,Jing-qiao Bai,Ning Lv,You-Lin Qiao,Feng Xu,Hai-zhi Qi 한국유방암학회 2013 Journal of breast cancer Vol.16 No.1

Purpose: This study aims to analyze the clinical-pathological characteristics of multifocal and multicentric breast cancer (MMBC) in Chinese women. Methods: Sixty-seven cases with MMBC were randomly collected and reviewed at seven hospitals in representative districts of China during 1999 to 2008. Results: The incidence of MMBC in breast cancer in China was 1.75%. Compared to those with unifocal breast cancer, women with MMBC were more likely to have larger tumor size, lymph node metastasis (59.70% vs. 45.62%) and stage III to IV (46.26% vs. 21.10%). The peak age at onset of MMBC was 40 to 49 years old and has been gradually increasing during 1999 to 2008. Most of the MMBC women were treated with surgery and adjuvant therapy. Conclusion: In China, the incidence of MMBC in breast cancer is significantly lower than that in Western countries. Compared to unifocal breast cancer, MMBC is biologically more aggressive. Most MMBC women underwent mastectomy, instead of breast conservation surgery.

Metabolomic analysis of biochemical changes in the tissue and urine of proteoglycan-induced spondylitis in mice after treatment with moxibustion

Xiao Xu,Ya-Nan Shi,Rong-Yun Wang,Cai-Yan Ding,Xiao Zhou,Yu-Fei Zhang,Zhi-Ling Sun,Zhi-Qin Sun,Qiu-Hua Sun 한국한의학연구원 2021 Integrative Medicine Research Vol.10 No.1

Background: Moxibustion is widely used in East Asian countries to manage the symptom of rheumatic diseases. The aim of this study was to identify potential metabolic profiles of moxibustion on relieving ankylosing spondylitis (AS) mice through UHPLC-Q-TOF/MS metabolomic study. Methods: Thirty-two female Balb/c mice were randomized into healthy control (HC), AS model, moxibustion at acupuncture points (MA) in AS model, and moxibustion at non-acupuncture points (MNA) AS model groups. Moxibustion was administered daily at GV4, bilateral BL23 and bilateral ST36 acupuncture points for four weeks in the MA group. The overall health status, the thickness of hind paws and the tissue concentrations of IL-1β, PGE2, IL-6 and TNF-α were assessed. The UHPLC-Q-TOF/MS was used to explore the perturbations of endogenous metabolites in tissue and urine of AS model mice intervened by moxibustion. Results: Compared with the AS group, the overall health status was significantly improved after 4-week moxibustion intervention (p < 0.05). The results also showed that MA significantly reduced the levels of paw thickness and decreased the levels of four cytokines in the tissue (p < 0.01). Thirty-seven endogenous metabolites identified by the OPLS-DA were considered to be contributing to therapeutic effects of moxibustion. Moreover, metabolic pathway analysis further revealed that the identified metabolites were mainly involved in TCA cycle, Lipid metabolism, Amino Acid metabolism, Intestinal flora metabolism and Purine metabolism. Conclusions: UHPLC-Q-TOF/MS based metabolomics approach, as a novel and powerful tool, can help us to gain the insights into potential mechanisms of action of moxibustion for AS.

Preparation of HMX by Catalytic Nitrolysis of DPT in AIL-N₂O₅-HNO₃ System

He, Zhi-Yong,Luo, Jun,Lu, Chun-Xu,Wang, Ping,Xu, Rong,Li, Jin-Shan Korean Chemical Society 2011 Bulletin of the Korean Chemical Society Vol.32 No.8

Direct nitrolysis of 3,7-dinitro-1,3,5,7-tetraazabicyclo[3,3,1]nonane (DPT) is a feasible way to synthesize HMX, and it has multiple practical applications. In this paper, a new nitrolysis process involving the use of an $N_2O_5-HNO_3$ system catalyzed by acidic ionic liquids (AILs) was developed. The results show that [$Et_3NH$]TsO was the best catalyst among the 28 AILs used and that HMX was formed at a higher yield of 61%, compared to 45% without any AIL. Moreover, with the addition of $N_2O_5$, the yield was further increased to a maximum value of 69%. The AILs were also efficiently recovered by simple extractions without any apparent loss of catalytic activity, even after five runs.

Metastasis associated genomic aberrations in stage II rectal cancer

Hong Zhao,Zhi-Zhou Shi,Rui Jiang,Dong-Bing Zhao,Hai-Tao Zhou,Jian-Wei Liang,Xin-Yu Bi,Jian-Jun Zhao,Zhi-Yu Li,Jian-Guo Zhou,Zhen Huang,Ye-Fan Zhang,Jian Wang,Xin Xu,Yan Cai,Ming-Rong Wang,Yu Zhang 한국유전학회 2016 Genes & Genomics Vol.38 No.11

Genomic aberrations of rectal carcinoma, especially DNA copy number changes associated with metastasis were largely unclear. We aim to identify the metastasis associated biomarkers in stage II rectal cancer. Formalin-fixed, paraffin-embedded primary tumor tissues of stage II rectal carcinoma were analyzed by array-based comparative genomic hybridization, and genomic aberrations were identified by Genomic Workbench and SAM software. Copy number changes and mRNA expressions were validated by Real-time PCR in an independent rectal cancer samples. The results showed that the most frequent gains in stage II rectal cancer were at 1q21.2-q23.1, 3p21.31, 11q12.2-q23.3, 12q24.11-q24.31, 12q13.11-q14.1 and losses in 18q11.2-q23, 17q21.33-q22, 13q31.1-q31.3, 21q21.1-q21.3, 8p23.3-p23.1 and 4q22.1-q23. Twenty-two amplifications and five homozygous deletions were also identified. We further found that S100A1 (1q21.3-q23.1), MCM7 (7q22.1) and JUND (19p13.11) were amplified and overexpressed in stage II rectal cancer. Interestingly, the genomic aberrations affected 14 signaling pathways including VEGF signaling pathway and fatty acid metabolism. Most importantly, loss of 13q31.1-q34 and gain of 1q44 were associated with distant metastasis. Our results indicated that these metastasis associated genomic changes may be useful to reveal the pathogenesis of rectal cancer metastasis and identify candidate biomarkers.

Histological Validation of Cardiovascular Magnetic Resonance T1 Mapping for Assessing the Evolution of Myocardial Injury in Myocardial Infarction: An Experimental Study

Zhang Lu,Yang Zhi-gang,Xu Huayan,Yang Meng-xi,Xu Rong,Chen Lin,Sun Ran,Miao Tianyu,Zhao Jichun,Zhou Xiaoyue,Fu Chuan,Guo Yingkun 대한영상의학회 2020 Korean Journal of Radiology Vol.21 No.12

Objective: To determine whether T1 mapping could monitor the dynamic changes of injury in myocardial infarction (MI) and be histologically validated. Materials and Methods: In 22 pigs, MI was induced by ligating the left anterior descending artery and they underwent serial cardiovascular magnetic resonance examinations with modified Look-Locker inversion T1 mapping and extracellular volume (ECV) computation in acute (within 24 hours, n = 22), subacute (7 days, n = 13), and chronic (3 months, n = 7) phases of MI. Masson’s trichrome staining was performed for histological ECV calculation. Myocardial native T1 and ECV were obtained by region of interest measurement in infarcted, peri-infarct, and remote myocardium. Results: Native T1 and ECV in peri-infarct myocardium differed from remote myocardium in acute (1181 ± 62 ms vs. 1113 ± 64 ms, p = 0.002; 24 ± 4% vs. 19 ± 4%, p = 0.031) and subacute phases (1264 ± 41 ms vs. 1171 ± 56 ms, p < 0.001; 27 ± 4% vs. 22 ± 2%, p = 0.009) but not in chronic phase (1157 ± 57 ms vs. 1120 ± 54 ms, p = 0.934; 23 ± 2% vs. 20 ± 1%, p = 0.109). From acute to chronic MI, infarcted native T1 peaked in subacute phase (1275 ± 63 ms vs. 1637 ± 123 ms vs. 1471 ± 98 ms, p < 0.001), while ECV progressively increased with time (35 ± 7% vs. 46 ± 6% vs. 52 ± 4%, p < 0.001). Native T1 correlated well with histological findings (R2 = 0.65 to 0.89, all p < 0.001) so did ECV (R2 = 0.73 to 0.94, all p < 0.001). Conclusion: T1 mapping allows the quantitative assessment of injury in MI and the noninvasive monitoring of tissue injury evolution, which correlates well with histological findings.