An Improved Adaptive Full-Order Sliding-Mode Observer for Sensorless Control of High-Speed Permanent-Magnet Synchronous Motor

Yao Runhui,Zhou Jin,Shi Jinwei,Ling Yangyi,Jiang Qiqi 대한전기학회 2024 Journal of Electrical Engineering & Technology Vol.19 No.3

The development of advanced sensorless control of high-speed permanent-magnet synchronous motor (PMSM) has been an ever-increasing demand in modern drive felds. Herein, in this article, an improved adaptive full-order sliding-mode observer (FSMO) for sensorless control of high-speed PMSM is proposed to improve the estimation accuracy of rotor speed and position. A model-referenced adaptive electrical angular velocity & back electromotive force (back EMF) observer is established. The estimated electrical angular velocity is directly fed back to the FSMO, which highly reduces the noise in the FSMO & phase-locked loop (PLL) system and weakens the chattering of the back EMF waveform, so that the estimation accuracy of the PLL on rotor speed and position is signifcantly improved. Simulations and experiments compared with the conventional method are both carried out with a 3 kW high-speed PMSM. The experimental results demonstrate that the proposed FSMO has preferable speed and position estimation capabilities under various operating conditions, which verifes the feasibility and superiority of the proposed method

Aberrant Expression of Markers of Cancer Stem Cells in Gastric Adenocarcinoma and their Relationship to Vasculogenic Mimicry

Zhou, Lei,Yu, Lan,Feng, Zhen-Zhong,Gong, Xiao-Meng,Cheng, Ze-Nong,Yao, Nan,Wang, Dan-Na,Wu, Shi-Wu Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.10

Background: Gastric cancer is the second leading cause of cancer-related death in Asia, and the majority type is gastric adenocarcinoma (GAC). Most GAC patients die of recurrence and metastasis. Cancer stem cells (CSCs) have been thought to be responsible for the initiation, development, metastasis, and ultimately recurrence of cancer. In this study, we aimed to investigate expression and clinical significance of CSCs markers, CD133 and Lgr5, and vasculogenic mimicry (VM) in primary GAC. Materials and Methods: Specimens from 261 Chinese patients with follow-up were analyzed for CD133, Lgr5 protein expression and VM by immunohistochemical and histochemical staining. The Pearson Chi's square test was used to assess the associations among the positive staining of these markers and clinicopathological characteristics. Postoperative overall survival time was were studied by univariate and multivariate analyses. Results: In GAC tissues, positive rates of 49.0%, 38.7%, and 26.8% were obtained for CD133, Lgr5, and VM, respectively. The mean score of microvessel density (MVD) was $21.7{\pm}11.1$ in GAC tissues. There was a significantly difference between the positive and negative groups. There was a positive relationship between the VM, the expression of CD133 and Lgr5, and the score of MVD and the grades of tumor, lymph node metastasis, TNM stages (all p<0.05). The overall mean survival time of the patients with CD133, Lgr5, VM, and MVD (${\geq}22$) positive expression was lower than that of patients with negative expression. The score of MVD, positive expression of CD133 and VM were independent prognostic factors of GAC (p<0.05). Conclusions: VM, and expression of CD133, Lgr5, and the score of MVD are related to grades of tumor, lymph node metastasis, TNM stages, and overall mean survival time. It is suggested that CSCs and VM could play an important role in the evolution of GAC.

Effect of Ca²⁺ on the activity and structure of α-glucosidase: Inhibition kinetics and molecular dynamics simulations

Zhang, X.,Shi, L.,Li, X.,Sheng, Q.,Yao, L.,Shen, D.,Lu, Z.R.,Zhou, H.M.,Park, Y.D.,Lee, J.,Zhang, Q. Society for Bioscience and Bioengineering, Japan ; 2014 Journal of bioscience and bioengineering Vol.117 No.6

Understanding the mechanism of inhibition of α-glucosidase (EC 3.2.1.20) is clinically important because of the involvement of this enzyme in type 2 diabetes mellitus. In this study, we conducted inhibition kinetics of α-glucosidase with Ca<SUP>2+</SUP> and 10-ns molecular dynamics simulations. We found that direct binding of Ca<SUP>2+</SUP> to the enzyme induced structural changes and inhibited enzyme activity. Ca<SUP>2+</SUP> inhibited α-glucosidase in a mixed-type reaction (K<SUB>i</SUB> = 27.0 +/- 2.0 mM) and directly induced the unfolding of α-glucosidase, which resulted in the exposure of hydrophobic residues. The simulations suggest that thirteen Ca<SUP>2+</SUP> ions may interact with α-glucosidase residues and that the Ca<SUP>2+</SUP> binding sites are associated with the structural changes in α-glucosidase. Our study provides insight into the mechanism of the Ca<SUP>2+</SUP>-induced structural changes in α-glucosidase and the inhibition of ligand binding. These results suggest that Ca<SUP>2+</SUP> could act as a potent inhibitor of α-glucosidase for the treatment of type 2 diabetes mellitus.

Expression of HERC4 in Lung Cancer and its Correlation with Clinicopathological Parameters

Zeng, Wen-Li,Chen, Yao-Wu,Zhou, Hui,Zhou, Jue-Yu,Wei, Min,Shi, Rong Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.2

Background: Growing evidence suggests that the members of the ubiquitin-proteasome system (UPS) are important for tumorigenesis. HERC4, one component, is a recently identified ubiqutin ligase. However, the expression level and function role of HERC4 in lung cancer remain unknown. Our objective was to investigate any correlation between HERC4 and development of lung cancer and its clinical significance. Materials and Methods: To determine HERC4 expression in lung cancer, an immunohistochemistry analysis of a tissue microarray containing samples of 10 lung normal tissues, 15 pulmonary neuroendocrine carcinomas, 45 squamous epithelial cancers and 50 adenocarcinomas was conducted. Receiver operating characteristic (ROC) curve analysis was applied to obtain a cut-off point of 52.5%, above which the expression of HERC4 was regarded as "positive". Results: On the basis of ROC curve analysis, positive expression of HERC4 was detected in 0/10 (0.0%) of lung normal tissues, in 4/15 (26.7%) of pulmonary neuroendocrine carcinomas, in 13/45 (28.9%) of squamous epithelial cancers and in 19/50 (38.0%) of adenocarcinomas. It showed that lung tumors expressed more HERC4 protein than adjacent normal tissues (${\chi}^2$=4.675, p=0.031). Furthermore, HERC4 positive expression had positive correlation with pT status (${\chi}^2$=44.894, p=0.000), pN status (${\chi}^2$=43.628, p=0.000), histological grade (${\chi}^2$=7.083, p=0.029) and clinical stage (${\chi}^2$=72.484, p=0.000), but not age (${\chi}^2$=0.910, p=0.340). Conclusions: Our analysis suggested that HERC4 is likely to be a diagnostic biomarker for lung cancer.

Convenient Synthesis of N-Methylpyrrolidine-2-thione and Some Thioamides

Zong, Zhi-Min,Peng, Yao-Li,Liu, Zhi-Gang,Zhou, Shi-Lu,Wu, Lin,Wang, Xiao-Hua,Wei, Xian-Yong,Lee, Chul Wee 한국화학공학회 2003 Korean Journal of Chemical Engineering Vol.20 No.2

The synthesis of thioamides and thiolactams, which are used as important organic intermediates, has attracted great attention. However, expensive reagents, severe reaction conditions and low yields of the target products made conventional methods inconvenient and economically infeasible. To overcome these disadvantages, we investigated a new process for synthesizing thioamides and thiolactams. We examine thermal reactions of CS_2 with N-methyl-2-pyrrolidinones, formylamide, acetamide and N, N-dimethylformylamide, respectively. The results show that under optimum conditions N-methylpyttolidine-2-thione and the corresponding thioamides can be obtained in good to excellent yields by the above thionation reactions.

Grain-Refinement and Mechanical Properties Optimisation of A356 Casting Al by Ultrasonic-Assisted Friction Stir Processing

Lin Ma,Changzhuang Zhou,Yao Shi,Qinghe Cui,Shude Ji,Kang Yang 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.12

Conventional friction stir processing (FSP) and ultrasonic-assisted friction stir processing (Ua-FSP) were applied to modifythe microstructure and enhance the mechanical properties of as-cast A356 aluminium alloy. A series of experiments withdifferent processing parameters were conducted in these two processing methods. Forming characteristics, grain-refinement,and mechanical properties in FSP and Ua-FSP were compared to determine the effect of ultrasound. The results revealed thatultrasound improved the grain-refinement level in both grain size and grain uniformity. Further, the effect of ultrasound onmicrostructural evolution was more significant with relatively high processing heat-input. Ultrasonic vibration also positivelyaffected the hardness, tensile strength, and elongation.

Comparative Genomics Profiling of Clinical Isolates of Helicobacter pylori in Chinese Populations Using DNA Microarray

Han, Yue-Hua,Liu, Wen-Zhong,Shi, Yao-Zhou,Lu, Li-Qiong,Xiao, Shudong,Zhang, Qing-Hua,Zhao, Guo-Ping The Microbiological Society of Korea 2007 The journal of microbiology Vol.45 No.1

In order to search for specific genotypes related to this unique phenotype, we used whole genomic DNA microarray to characterize the genomic diversity of Helicobacter pylori (H. pylori) strains isolated from clinical patients in China. The open reading frame (ORF) fragments on our microarray were generated by PCR using gene-specific primers. Genomic DNA of H. pylori 26695 and J99 were used as templates. Thirty-four H. pylori isolates were obtained from patients in Shanghai. Results were judged based on In(x) transformed and normalized Cy3/Cy5 ratios. Our microarray included 1882 DNA fragments corresponding to 1636 ORFs of both sequenced H. pylori strains. Cluster analysis, revealed two diverse regions in the H. pylori genome that were not present in other isolates. Among the 1636 genes, 1091 (66.7%) were common to all H. pylori strains, representing the functional core of the genome. Most of the genes found in the H. pylori functional core were responsible for metabolism, cellular processes, transcription and biosynthesis of amino acids, functions that are essential to H. pylori's growth and colonization in its host. In contrast, 522 (31.9%) genes were strain-specific genes that were missing from at least one strain of H. pylori. Strain-specific genes primarily included restriction modification system components, transposase genes, hypothetical proteins and outer membrane proteins. These strain-specific genes may aid the bacteria under specific circumstances during their long-term infection in genetically diverse hosts. Our results suggest 34 H. pylori clinical strains have extensive genomic diversity. Core genes and strain-specific genes both play essential roles in H. pylori propagation and pathogenesis. Our microarray experiment may help select relatively significant genes for further research on the pathogenicity of H. pylori and development of a vaccine for H. pylori.

Gene Expression Profile of Helicobacter pylori in Response to Growth Temperature Variation

Yue-hua Han,Wen-zhong Liu,Yao-zhou Shi,Li-qiong Lu,Shu-dong Xiao,Qing-hua Zhang 한국미생물학회 2009 The journal of microbiology Vol.47 No.4

A Helicobacter pylori whole-genome DNA microarray was constructed to study expression profiles of H. pylori in response to a sudden temperature transfer from 37°C to 20°C. The expression level of the genome at each of four time points (15, 30, 60, and 120 min) after temperature downshift was compared with that just before cold treatment. Globally, 10.2% (n=167) of the total predicted H. pylori genes (n=1636) represented on the microarray were significantly differentially expressed (p<0.05) over a 120 min period after shift to low temperature. The expression profiles of the differentially expressed genes were grouped, and their expression patterns were validated by quantitative real-time PCR. Up-regulated genes mainly included genes involved in energy metabolism and substance metabolism, cellular processes, protein fate, ribosomal protein genes, and hypothetical protein genes, which indicate the compensational responses of H. pylori to temperature downshift. Those genes play important roles in adaption to temperature downshift of H. pylori. Down-regulation of DNA metabolism genes and cell envelope genes and cellular processes genes may reflect damaged functions under low temperature, which is unfavorable to bacterial infection and propagation. Overall, this time-course study provides new insights into the primary response of H. pylori to a sudden temperature downshift, which allow the bacteria to survive and adapt to the new host environment.

Comparative Genomics Profiling of Clinical Isolates of Helicobacter pylori in Chinese Populations Using DNA Microarray

Yue-Hua Han,Wen-Zhong Liu,Yao-Zhou Shi,Li-Qiong Lu,Shudong Xiao,Qing-Hua Zhang,Guo-Ping Zhao 한국미생물학회 2007 The journal of microbiology Vol.45 No.1

In order to search for specific genotypes related to this unique phenotype, we used whole genomic DNA microarray to characterize the genomic diversity of Helicobacter pylori (H. pylori) strains isolated from clinical patients in China.The open reading frame (ORF) fragments on our microarray were generated by PCR using gene-specific primers. Genomic DNA of H. pylori 26695 and J99 were used as templates. Thirty-four H. pylori isolates were obtained from patients in Shanghai. Results were judged based on ln(x) transformed and normalized Cy3/Cy5 ratios. Our microarray included 1882 DNA fragments corresponding to 1636 ORFs of both sequenced H. pylori strains. Cluster analysis, revealed two diverse regions in the H. pylori genome that were not present in other isolates. Among the 1636 genes, 1091 (66.7%) were common to all H. pylori strains, representing the functional core of the genome. Most of the genes found in the H. pylori functional core were responsible for metabolism, cellular processes, transcription and biosynthesis of amino acids, functions that are essential to H. pylori’s growth and colonization in its host. In contrast, 522(31.9%) genes were strain-specific genes that were missing from at least one strain of H. pylori. Strainspecific genes primarily included restriction modification system components, transposase genes, hypothetical proteins and outer membrane proteins. These strain-specific genes may aid the bacteria under specific circumstances during their long-term infection in genetically diverse hosts. Our results suggest 34 H. pylori clinical strains have extensive genomic diversity. Core genes and strain-specific genes both play essential roles in H. pylori propagation and pathogenesis. Our microarray experiment may help select relatively significant genes for further research on the pathogenicity of H. pylori and development of a vaccine for H. pylori.

Effects of Xylanase on Performance, Blood Parameters, Intestinal Morphology, Microflora and Digestive Enzyme Activities of Broilers Fed Wheat-based Diets

Luo, Dingyuan,Yang, Fengxia,Yang, Xiaojun,Yao, Junhu,Shi, Baojun,Zhou, Zhenfeng Asian Australasian Association of Animal Productio 2009 Animal Bioscience Vol.22 No.9

The study was conducted to investigate the effects of different levels of xylanase on performance, blood parameters, intestinal morphology, microflora and digestive enzyme activities of broilers. The wheat-based diets were supplemented with 0, 500, 1,000, 5,000 U/kg xylanase. Xylanase supplementation significantly (p<0.05) improved the feed:gain ratio of broilers from 1 to 21 d and 1 to 42 d. Supplementing 500 U/kg and 1,000 U/kg xylanase improved (p<0.05) the villus height and the ratio of villus height to crypt depth in the small intestine. Excess supplementation of xylanase (5,000 U/kg) increased the villus height in the ileum (p<0.01) and the ratio of villus height to crypt depth in the duodenum and ileum (p<0.05). The microflora in the ileum and caecum, digestive enzyme activities in the small intestine and the concentrations of serum glucose, uric acid, insulin and IGF-I were not affected by the supplementation of xylanase. Excess level of xylanase (5,000 U/kg) had a tendency to induce the multiplication of E. coli and total aerobes. The results suggested that supplementing 500 U/kg and 1,000 U/kg xylanase was beneficial for broilers and excess xylanase supplementation resulted in no further improvement or negative effects.