Fabrication of Magnetite Nanoparticle-embedded Polystyrene Composites and Their Additive Role on the Dynamic Properties of Carbonyl Iron-based Magneto-rheological Fluids

Chun Yan Gao,Qi Lu,Hyoung Jin Choi,Nam Hui Kim,Chun Yeol You 한국자기학회 2019 Journal of Magnetics Vol.24 No.1

Magnetic Fe₃O₄@polystyrene (PS) nanoscale composite particles were fabricated using a unique Shirasu porous-glass membrane technique and used as additives to a magnetorheological (MR) suspension with magnetic carbonyl-iron (CI) particles. The morphology of the fabricated Fe₃O₄@PS composites was characterized by transmission electron microscopy. The effects of the Fe₃O₄@PS composite particle additive on its MR behavior was examined using a rotation rheometer under an applied magnetic field. The results revealed improved MR behavior, such as higher storage and loss moduli, and elastic yield stress compared to those of the pure CIbased MR suspension under an external magnetic field.

Hollow submicron-sized spherical conducting polyaniline particles and their suspension rheology under applied electric fields

Gao, Chun Yan,Meng, Long-Yue,Piao, Shang Hao,Choi, Hyoung Jin Elsevier 2018 Polymer Vol.140 No.-

<P><B>Abstract</B></P> <P>Conducting polymeric polyaniline hollow spheres (PANI-HS) were fabricated and evaluated as a smart electro-stimuli responsive material, whose both special structure of shorter diffusion length promotes the electron transfer and specific surface area is greatly amplified than solid spheres. The monodisperse polystyrene (PS) seeds were initially synthesized by a facile surfactant-free emulsion polymerization, and then the monomer aniline was adsorbed and polymerized on the sulfonated PS spheres to form the PS/polyaniline (PANI) composites, allowing the PS cores to be removed by a solvent extraction later. The morphology and shell thickness were examined using both scanning electron microscopy and transmission electron microscopy. Fourier transformation infrared spectroscopy affirmed chemical structure of pure PS, PS/PANI and PANI-HS. The dielectric spectra were further analyzed for their electrorheological (ER) characteristics with LCR meter. The homogeneous semi-conducting PANI-HS based ER fluid (10 vol%) exhibited typical ER characteristics according with the conductivity model based on a slope of 1.5.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Hollow polyaniline (PANI-HS) was adopted as an electrorheological (ER) material. </LI> <LI> Its special structure of shorter diffusion length promotes electron transfer. </LI> <LI> PS cores in PS/PANI composite were removed by solvent extraction. </LI> <LI> ER fluid showed typical ER characteristics with a slope of 1.5. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Conducting polyaniline hollow submicron-sized spheres (PANI-HS) were fabricated and evaluated as a smart electro-stimuli responsive material. Polystyrene (PS) seeds were initially synthesized by a facile surfactant-free emulsion polymerization, and then the aniline was adsorbed and polymerized on the sulfonated PS spheres to form the PS/PANI composites, allowing the PS cores to be removed by a solvent extraction later. Their electrorheological behaviors of hollow PANI based ER fluid (10 vol %) were observed using a rotational rheometer at different electric field strengths, showing dramatic electro-stimuli responsive phase transition.</P> <P>[DISPLAY OMISSION]</P>

ANXA2 Regulates the Behavior of SGC-7901 Cells

Sun, Meng-Yao,Xing, Rui-Huan,Gao, Xiao-Jie,Yu, Xiang,He, Hui-Min,Gao, Ning,Shi, Hong-Yan,Hu, Yan-Yan,Wang, Qi-Xuan,Xu, Jin-Hui,Hou, Ying-Chun Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.10

ANXA2, a member of the annexin family, is overexpressed and plays important roles in tumor development. However, the significance of ANXA2 expression in gastric carcinoma has not been clarified.To elucidate its roles in growth of gastric cancer, ANXA2 expression in SGC-7901 cells was inhibited with a designated siRNA, then cell proliferation, cell cycling, apoptosis and motility were determined by MTT assay, flow cytometry, Hoechst 33342 staining and wound healing assay, respectively. To further assess the behavior of ANXA2 deleted SGC-7901 cells, changes of microstructures were observed under fluorescence microscopy, laser scanning confocal microscopy and electron microscopy. We found that inhibition of ANXA2 expression caused cell proliferation to decrease significantly with G1 arrest, motility to be reduced with changes in pseudopodia/filopodia structure and F-actin and ${\beta}$-tubulin expression, and apoptosis to be enhanced albeit without significance. At the same time, ANXA2 deletion resulted in fewer pseudopodia/filopodia, non-stained areas were increased, contact inhibition among cells reappeared, and expression of F-actin and ${\beta}$-tubulin was decreased, with induction of polymerized disassembled forms. Taken together, these data suggest that ANXA2 overexpression is important to maintain the malignancy of cancer cells, and this member of the annexin family has potential to be considered as a target for the gene therapy of gastric carcinoma.

Butyrolactones Derivatives from the Fermentation Products of an Endophytic Fungus Aspergillus versicolor

Yan-Qing Ye,Cong-Fang Xia,Juan-Xia Yang,Yu-Chun Yang,Ying Qin,Xue-Mei Gao,Gang Du,Xuemei Li,Qiu-Fen Hu 대한화학회 2014 Bulletin of the Korean Chemical Society Vol.35 No.10

Two new butyrolactones, asperphenol A (1) and B (2), together with four known butyrolactones (3-6) were isolated from the fermentation products of an endophytic fungus Aspergillus versicolor. Their structures were elucidated by spectroscopic methods including extensive 1D- and 2D-NMR techniques. Compounds 1-6 were also tested for their anti-tobacco mosaic virus (anti-TMV) activities. The results showed that compound 2 exhibited high anti-TMV activity with inhibition rate of 46.7%. The other compounds also exhibited potential anti-TMV activities with inhibition rates in the range of 21.8-28.4%.

Promoted Growth of Maize by the Phosphate Solubilizing Bacteria Isolated from North-east China

Hai-Yan Wu,Li-Chun Wang,Xing-Ai Gao,Rong-De Jin,Zuo-Wei Fan,Kil-Yong Kim,Lan-Po Zhao 한국토양비료학회 2011 한국토양비료학회지 Vol.44 No.1

A strain of phosphate solubilizing bacterium was isolated from rhizosphere and identified as Burkholderia sp. by 16S-rRNA gene sequence analyses. The bacterium was found to release gluconic acid and the solubilization of hydroxyapatite in the liquid medium by a significant drop in pH to 3.7 from an initial pH 7.0. The soluble-P concentration continuously increased during the incubation periods and the total amount of soluble P released in culture filtrate was detected at 990 mg L<SUP>-1</SUP> after 10 days of inoculation. Most promoted maize growth was found in the standard NPK (240-120-120 kg ha<SUP>-1</SUP>) soil inoculation with Burkholderia sp. (Twenty milliliters/ plant, 106 CFU) and also in the absence of Burkholderia sp. inoculation, the soil amended with only 2/3 levels of P gave significant higher plant yield compared to 1/3 levels of P or without P supplementation.

Butyrolactones Derivatives from the Fermentation Products of an Endophytic Fungus Aspergillus versicolor

Ye, Yan-Qing,Xia, Cong-Fang,Yang, Juan-Xia,Yang, Yu-Chun,Qin, Ying,Gao, Xue-Mei,Du, Gang,Li, Xue-Mei,Hu, Qiu-Fen Korean Chemical Society 2014 Bulletin of the Korean Chemical Society Vol.35 No.10

Two new butyrolactones, asperphenol A (1) and B (2), together with four known butyrolactones (3-6) were isolated from the fermentation products of an endophytic fungus Aspergillus versicolor. Their structures were elucidated by spectroscopic methods including extensive 1D- and 2D-NMR techniques. Compounds 1-6 were also tested for their anti-tobacco mosaic virus (anti-TMV) activities. The results showed that compound 2 exhibited high anti-TMV activity with inhibition rate of 46.7%. The other compounds also exhibited potential anti-TMV activities with inhibition rates in the range of 21.8-28.4%.

Chinese Word Sense Disambiguation Based on Hidden Markov Model

Zhang Chun-Xiang,Sun Yan-Chen,Gao Xue-Yao,Lu Zhi-Mao 보안공학연구지원센터 2015 International Journal of Database Theory and Appli Vol.8 No.6

Word sense disambiguation (WSD) is important for natural language processing. It plays important roles in information retrieval, machine translation, text categorization and topic tracking. In this paper, the transition among senses of words is considered. For an ambiguous word, its semantic codes and its left word’s semantic codes are taken as disambiguation features. At the same time, a new method based on hidden Markov model (HMM) is proposed for Chinese word sense disambiguation. Chinese Tongyici Cilin is used to determine semantic codes of words. HMM is optimized in training corpus. The WSD classifiers based on HMM is tested. Experimental results show that the accuracy of word sense disambiguation is improved.

Flavones from the Bark of Lindera caudata and Their Anti-Tobacco Mosaic Virus Activity

Yu-Chun Yang,Ying Qin,Xian-Xue Wu,Cong-Fang Xia,Yan-Lin Meng,Bin Zhou,Yan-Qing Ye,Xue-Mei Gao,Yin-Ke Li,Qiu-Fen Hu 대한화학회 2015 Bulletin of the Korean Chemical Society Vol.36 No.4

Two new flavones, 5-hydroxy-8-hydroxymethyl-7,4′-dimethoxy-flavone (1) and 6-hydroxy-8-hydroxymethyl-7,4′-dimethoxy-flavone (2), together with six known flavones (3–8), were isolated from the bark of Lindera caudata. The structures of 1–8 were elucidated by spectroscopic methods including extensive 1D and 2D NMR techniques. Compounds 1–8 were evaluated for their anti-tobacco mosaic virus (anti-TMV) activity. The results showed that Compounds 1 and 2 showed high anti-TMV activity with inhibition rates of 31.2 and 28.8%, respectively. These values are close to those of positive control.

Vapor phase condensation of methyl acetate with formaldehyde to preparing methyl acrylate over cesium supported SBA-15 catalyst

Jianbiao Yan,Chunlei Zhang,Chunli Ning,Yong Tang,Yi Zhang,Lili Chen,Shuang Gao,Zhenlu Wang,Wenxiang Zhang 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.25 No.-

A cesium ion-containing catalyst, on an SBA-15 mesoporous molecular support, was prepared by the impregnation method and applied to the aldol condensation of methyl acetate with formaldehyde. The catalyst showed high catalytic activity in the condensation reaction. XRD characterization indicated that the cesium nitrate below 5 wt% loading was highly dispersed on the SBA-15 support. FT-IR and XPS results confirmed that a Si–O–Cs species was formed on the surface of the catalyst. Pyridine-IR verified that an L-acid site existed on the surface. The NH3-TPD and CO2-TPD results indicated that weak Lewis acid–base pairs were loaded on the surface, and these weak acid–base active sites might favor the aldol condensation reaction. The 5Cs/SBA-15 catalyst demonstrated the highest (48.4%) conversion of methyl acetate reported and 95.0% selectivity for methyl acrylate. The deactivated catalyst was completely regenerated by calcination. The catalyst was regenerated nine times with a total operation time of more than 60 h, and the initial conversion of methyl acetate and the selectivity for methyl acrylate did not change. The high catalytic activity was mainly due to the suitable strength of weak acid–base properties, which were rooted in the Si–O–Cs species on the surface of the support.

Cloning and analysis of b-amyrin synthase gene in Bupleurum chinense

Ke Gao,Su-rui Wu,Ling Wang,Yan-hong Xu,Jian-he Wei,Chun Sui 한국유전학회 2015 Genes & Genomics Vol.37 No.9

Bupleurum chinense DC. is one of the source plants of a well-known crude drug, Chai hu (Radix Bupleuri), producing triterpenoid saponins (saikosaponins) with a wide-spectrum of pharmacological applications. The biosynthesis of triterpenoid saponins involved with the cyclizing of the precursor 2,3-oxidosqualene to produce the first committed triterpene b-amyrin catalyzed by b-amyrin synthase (b-AS), whereafter diverse of triterpenoid saponins was biosynthesized. In addition, 2,3-oxidosqualene could be catalyzed by cycloartenol synthase directing to the synthesis of phytosterol. b-AS was thus defined as an important branch point between primary and secondary metabolisms, and may play a regulating role in the control of triterpenoid saponins biosynthesis. In this study, the promoter and protein-encoding regions of a b-AS gene (designated bcAS1) were isolated by genome walking and PCR from B. chinense. Several important cis-acting elements for gene regulation were identified within the promoter region including light-responsive, hormoneresponsive and various other stress-related elements. Approximate 0.8 kb fragment on upstream of ATG start codon of bcAS1 was sub-cloned into pAN580 vector to replace the 35S promoter driving the expression of green fluorescent protein (GFP) gene. The promoter activity was detected by transient expression in onion epidermis cells by the expression of GFP. Approximately 6 kb length of bcAS1 gene was cloned, containing 18 exons and 17 introns. Although a dozen of b-AS cDNA was isolated, seldom the promoter and gene of it was reported. This work was a valuable foundation for further studies on the regulatory role of b-AS in biosynthesis of saikosaponins.