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Enantioselective induction of oxidative stress by acetofenate in rat PC12 cells

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Journal of Environmental Sciences 2010年第12期22卷 1980-1986页

作者： ling li fen Hu Cui Wang Xuedong Wang Research Center of Environmental Science College of Biological and Environmental Engineering Zhejiang University of Technology Hangzhou 310032 China School of Environmental Science and Public Health Wenzhou Medical College Wenzhou 325035 China

In a non-chiral environment, the enantiomers of a racemate possessed the identical physico-cbemical properties, but in the biological systems they possessed different activities. Considering that the involvement of oxidative damage has been implicated in the toxicities of various pesticides, this study investigated the possibility of enantioselective oxidative stress and cytotoxicity induction by acetofenate （AF） which contains an asymmetrical center on PC12 cells. The results of the cytotoxicity assay indicated that S-（＋）-AF presented more toxic effects than R-（-）-AF and （＋）-AF. It also demonstrated that S-（＋）-AF possessed the strongest effects in induction of reactive oxygen species （ROS） production, decrease in superoxide dismutase （SOD） and catalase （CAT） activities, and increase in malondialdehyde （MDA） level. These results suggested that AF and its enanfiomers could induce enantioselecfive cytotoxicity in PC12 cells mediated by oxidative stress. Therefore, the assessment in environmental safety and new chiral pesticide development should consider enantioselectivity.

关键词： chiral organochlorine pesticides acetofenate enantioselectivity cytotoxicity oxidative stress

Characterization of a bioflocculant from a newly isolated Vagococcus sp. W31

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2006年第3期7卷 186-192页

作者： GAO Jie BAO Hua-ying XIN Ming-xiu liU Yuan-xia li Qian ZHANG Yan-fen School of Chemistry Beijing Normal University Beijing 100875 China School of life Science Beijing Normal University Beijing 100875 China

Screening of microorganisms producing flocculating substances was carried out. A strain secreting a large amount of bioflocculant was isolated from wastewater samples collected from the little Moon River in Beijing. Based on the morphological properties and 16S rDNA sequence analysis, the isolate (designated W31) was classified as Vagococcus sp. A bioflocculant (named MBFW31) produced by W31 was extracted from the culture broth by ethanol precipitation and purified by gel chroma-tography. MBFW31 was heat-stable and had strong flocculating activity in a wide range of pH with relatively low dosage re-quirement. MBFW31 was identified as a polysaccharide with molecular weight over 2×106. It contained neutral sugar and uronic acid as its major and minor components, respectively. Infrared spectra showed the presence of hydroxyl, carboxyl and methoxyl group in its molecules. The present results suggested that MBFW31 had potential application in wastewater treatment.

关键词： Vagococcus sp. Bioflocculant Characterization Flocculating activity

Optimal crater landmark selection based on optical navigation performance factors for planetary landing

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Chinese Journal of Aeronautics 2023年第3期36卷 254-270页

作者： Yi xiu Shengying ZHU Rui XU Maodeng li School of Aerospace Engineering Beijing Institute of TechnologyBeijing 100081China Key Laboratory of Autonomous Navigation and Control for Deep Space Exploration Ministry of Industry and Information TechnologyBeijing 100081China Key Laboratory of Dynamics and Control of Flight Vehicle Ministry of EducationBeijing 100081China Science and Technology on Space Intelligent Control Laboratory Beijing Institute of Control EngineeringBeijing 100091China

Planetary craters are natural navigation landmarks that widely exist and are easily *** navigation based on crater landmarks has become an important autonomous navigation method for planetary *** to the increase in observed crater landmarks and the limitation of onboard computation,the selection of good crater landmarks has gradually become a research hotspot in the field of landmark-based optical *** paper designs a fast crater landmark selection method,which not only considers the configuration observability of crater subsets but also focuses on the influence on navigation performance arising from the measurement uncertainty and the matching confidence of craters,which is different from other landmark selection *** factor of measurement uncertainty,which is anisotropic,correlated and nonidentically distributed,is quantified and integrated into selection based on crater pairing detection and localization error *** addition,the concept of the crater matching confidence factor is introduced,which reflects the possibility of 2D projection measurements corresponding to 3D *** with the configuration observability factor,the crater landmark selection indicator is ***,the effectiveness of the proposed method is verified by Monte Carlo simulations.

关键词： Crater-based optical navigation Crater landmark selection Crater matching Measurement uncertainty Planetary landing

Design and Properties of Fluoroelastomer Composites via Incorporation of MWCNTs with Varied Modification

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Chinese Journal of Polymer Science 2020年第9期38卷 983-992,I0007页

作者： Guang-Yao Yang li-fen Tong Xiao-Bo liu Research Branch of Advanced Functional Materials School of Materials and EnergyUniversity of Electronic Science and Technology of ChinaChengdu 610054China

Multi-walled carbon nanotubes(MWCNTs)modified with silane coupling agent A-1120(MWCNTs-A1120)were *** with the raw MWCNTs,acidified MWCNTs(MWCNTs-COOH),and MWCNTs grafted with EDA(MWCNTs-NH2),MWCNTs-A1120 have the best dispersion in fluoroelastomer at the same doping ***,fluoroelastomer/MWCNTs-A1120 composite has the best mechanical properties with tensile strength of 13.92 MPa and elongation at break of 111.78%.Then,the effects of doping amount of MWCNTs-A1120 on the electrical properties of the composites were *** dielectric constant of the composite increases with the increase of MWCNTs-A1120,and the dielectric loss does not change much at the low doping amount such as 0.5 wt%.When the doping amount of MWCNTs-A1120 is 5 wt%,the dielectric constant and the dielectric loss value are greatly increased,and the volume resistivity is greatly decreased,which proves that the conductive network is formed in the composite,so the filling amount of 5 wt%is the percolation *** tensile deformation of the sample also affects the electrical properties of the *** the tensile deformation increases,the dielectric constant and dielectric loss of the composite *** the composite with 5 wt%MWCNTs-A1120,excessive tensile deformation will destroy the conductive network structure of the composite,so the composite will change from conductive material to dielectric ***,such composite is a good candidate for flexible conductive material or flexible dielectric material used in harsh environments such as high temperatures and various aggressive solvents.

关键词： Modified-MWCNTs Fluoroelastomer nanocomposite Interface compatibility Dielectric properties Volume resistivity

High Acoustic Nonlinearity of a liquid Containing Microbubbles

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Chinese Physics Letters 1999年第10期16卷 737-739页

作者： liU Jie-hui ZHANG Dong GONG xiu-fen SHAO li-zheng li Xiao-rong CHEN Xi ZHANG Qin-lan State Key Laboratory of Modern Acoustics Institute of AcousticsNanjing UniversityNanjing 210093 Wuxi No.1 People’s Hospital Wuxi 214002

The acoustic nonlinearity parameter B/A of a liquid containing microbubbles,sonicated dextrose albumin,has been measured by using second harmonic insert-substitution *** show that the value of nonlinearity parameter B/A for a bubbly liquid is significant and it obviously increases with increase of bubble number *** high nonlinearity of the bubbly liquid is mainly dependent on the microbubble nonlinear oscillation.

关键词： oscillation. density. method.

Abnormal specific heat at low temperatures and transport properties in Mg-Cu-Ag-Gd bulk metallic glass

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Journal of Rare Earths 2023年第2期41卷 277-282页

作者： Qiang Zheng xiu Su lingyun li Juan Du Institute of Materials School of Materials Science and EngineeringShanghai UniversityShanghai 200072China

We report the pronounced low-temperature specific-heat Cpanomalies in the Mg_(59.5)Cu_(22.9)Ag_(6.6)Gd_(11)bulk metallic glass(BMG).The extrapolated electron’s temperature coefficientγ0Kis up to 681.8 mJ/(molGd·K^(2))at 0 K,which is a heavy-fermion-like *** low temperature specific heat indicates an enhancement of the conduction-electron effective mass m*below 7.5 K,suggesting that the Mg_(59.5)Cu_(22.9)Ag_(6.6)Gd_(11)BMG is not free-electron-like *** excess specific heat in the Mg-based BMG is interpreted with tunneling states and spin glass state(magnetism)which are determined by subtracting electrons’and phonons’contribution to the specific heat below 12 *** Boson peak(BP)temperature is located at 27 K,which is much higher than the reported values of other ***,a BP height of 0.047 mJ/(mol·K^(4))is obtained due to reduced free volume during copper mold casting with a slow cooling *** electrical resistivity was also investigated between 2 and 300 K,which has a negative temperature coefficient of resistivity(TCR)below 35 K(Kondo temperature,TK)and a positive value of 3.9×10^(-4)/K above 35 *** is a minimum at about 35 K for the electrical resistivity,which can be explained by the Kondo *** the resistivity above 35 K,it can be explained by the FaberZiman model due to the T-dependence change of structure factor.

关键词： Specific heat Boson peak Electrical resistivity Bulk metallic glass(BMG) Spin glass behavior Rare earths

Proteinase-activated receptor 2 promotes tumor cell proliferation and metastasis by inducing epithelialmesenchymal transition and predicts poor prognosis in hepatocellular carcinoma

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World Journal of Gastroenterology 2018年第10期24卷 1120-1133页

作者： liang Sun Pi-Bao li Yan-fen Yao Ai-Yuan xiu Zhi Peng Yu-Huan Bai Yan-Jing Gao Qilu Hospital of Shandong University Jinan 250012Shandong ProvinceChina Department of Critical Care Medicine Shandong Traffic HospitalJinan 250000Shandong provinceChina Department of Gastroenterology Qilu Hospital of Shandong UniversityJinan 250012Shandong provinceChina

AIM To clarify the role of proteinase-activated receptor 2(PAR2) in hepatocellular carcinoma, especially in the process of *** PAR2 expression levels were assessed by qRT-PCR and immunohistochemistry(IHC) in patient tissues and in hepatocellular carcinoma cell lines SMMC-7721 and Hep G2. Cell proliferation and metastasis were assessed both in vitro and in vitro. Immunoblotting was carried out to monitor the levels of mitogen-activated protein kinase(MAPK) and epithelial-mesenchymal transition *** The prognosis was significantly poorer in patients with high PAR2 levels than in those with low PAR2 levels. Patients with high PAR2 levels had advanced tumor stage(P = 0.001, chi-square test), larger tumor size(P = 0.032, chi-square test), and high microvascular invasion rate(P = 0.037, chi-square test). The proliferation and metastasis ability of SMMC-7721 and Hep G2 cells was increased after PAR2 overexpression, while knockdown of PAR2 decreased the proliferation and metastasis ability of SMMC-7721 and Hep G2 cells. Knockdown of PAR2 also inhibited hepatocellular carcinoma tumor cell growth and liver metastasis in nude mice. Mechanistically, PAR2 increased the proliferation ability of SMMC-7721 and Hep G2 cells via ERK activation. Activated ERK further promoted the epithelial-mesenchymal transition of these cells, which endowed them with enhanced migration and invasion ability. CONCLUSION These data suggest that PAR2 plays an important role in the proliferation and metastasis of hepatocellular carcinoma. Therefore, targeting PAR2 may present a favorable target for treatment of this malignancy.

关键词： Hepatocellular carcinoma Proteinaseactivated receptor 2 Epithelial-mesenchymal transition

Biosensor Based on TTF@SiO_2 Nanoparticles as Electron Transfer Mediator for the Determination of Glucose

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Chemical Research in Chinese Universities 2006年第4期22卷 474-478页

作者： li Xiao-hua XIAN Yue-zhong MIN Hong li Chen-xin XIE Zong-hong ZHANG fen-fen JIN li-tong Department of Chemistry East China Normal University Shanghai 200062 P. R. China

Tetrathiafulvalene（TTF） was doped in an SiO2 network and the resulting nanocompesite was used as a mediator for the selective detection of glucose. The uniform TTF-doped silica（TIT@SiO2 ） nanoparticles were prepared by the water-in-oil（W/O） microemulsion method, and were characterized by transmission electron microscopy（TEM）. The core-shell structure TTF@ SiO2 could prevent TIT from leaching out into an aqueous solution. Combined with chitosan （CHIT）, which serves as a scaffold for glucose oxidase and nanocomposite immobilization, the GCE/TTF@ SiO2- CHIT-GOx biosensor was developed. Under optimal conditions, the biosensors exhibit a linear range of 1.0 × 10^-5 5 × 10^-3 mol/L with a detection limit down to 5.0 μmol/L（S/N = 3 ）. The excellent selectivity, sensitivity, and stability of the glucose biosensor show its potential for practical applications.

关键词： TTF@ SiO2 nanoparticle Chitosan Glucose Biosensor

Thermodynamic Properties of linear Protein Solutions:an Application to Type Ⅰ Antifreeze Protein Solutions

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Chemical Research in Chinese Universities 2012年第6期28卷 1070-1073页

作者： li li-fen liANG Xi-xia li Qian-zhong Department of Physics lnner Mongolia University Hohhot 010021 P. R. China Department of Basic Curriculum North China Institute of Science and Technology Beijing 101601 P. R. China

A statistical thermodynamic theory of linear protein solutions was proposed with the aid of a lattice model and applied to type Ⅰ antifreeze protein（AFPI） *** numerical results for several AFPI solutions show that the Gibbs function of the solution has a minimum at a certain protein concentration,but the protein chemical potential increases with increasing the *** influences of temperature and protein chain length on the AFPI chemical potential were also *** evaluation for the colligative depression of the freezing point confirms that the antifreeze action should be recognized as *** theoretical deduction for the concentration dependence of the thermal hysteresis activity coincides qualitatively with the previous experimental and theoretical results.

关键词： Antifreeze protein solution Gibbs function Chemical potential Thermal hysteresis