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Search Results: 1 - 10 of 8857 matches for " Chunjuan Gu "
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Engineering the Expression and Characterization of Two Novel Laccase Isoenzymes from Coprinus comatus in Pichia pastoris by Fusing an Additional Ten Amino Acids Tag at N-Terminus
Chunjuan Gu, Fei Zheng, Liangkun Long, Jing Wang, Shaojun Ding
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0093912
Abstract: The detail understanding of physiological/biochemical characteristics of individual laccase isoenzymes in fungi is necessary for fundamental and application purposes, but our knowledge is still limited for most of fungi due to difficult to express laccases heterologously. In this study, two novel laccase genes, named lac3 and lac4, encoding proteins of 547 and 532-amino acids preceded by 28 and 16-residue signal peptides, respectively, were cloned from the edible basidiomycete Coprinus comatus. They showed 70% identity but much lower homology with other fungal laccases at protein level (less than 58%). Two novel laccase isoenzymes were successfully expressed in Pichia pastoris by fusing an additional 10 amino acids (Thr-Pro-Phe-Pro-Pro-Phe-Asn-Thr-Asn-Ser?)tag at N-terminus, and the volumetric activities could be dramatically enhanced from undetectable level to 689 and 1465 IU/l for Lac3 and Lac4, respectively. Both laccases possessed the lowest Km and highest kcat/Km value towards syringaldazine, followed by ABTS, guaiacol and 2,6-dimethylphenol similar as the low redox potential laccases from other microorganisms. Lac3 and Lac4 showed resistant to SDS, and retained 31.86% and 43.08% activity in the presence of 100 mM SDS, respectively. Lac3 exhibited higher decolorization efficiency than Lac4 for eleven out of thirteen different dyes, which may attribute to the relatively higher catalytic efficiency of Lac3 than Lac4 (in terms of kcat/Km) towards syringaldazine and ABTS. The mild synergistic decolorization by two laccases was observed for triphenylmethane dyes but not for anthraquinone and azo dyes.
Ohmic contact behaviour of Co/C/4H-SiC structures

Wang Yongshun,Liu Chunjuan,Gu Shengjie,Zhang Caizhen,

半导体学报 , 2011,
Abstract: 研究了Co/4H-SiC结构的电学特性。通过直流溅射的方式在金属Co 薄膜 与SiC之间淀积了一层碳薄膜,极大地改善了欧姆特性。采用两步快速退火工艺,即500 °C 退火 10 分钟 再 1050 °C 退火 3 分钟,形成了良好的欧姆接触,接触电阻率为2.30×10-6 Ω.cm2。X射线衍射(XRD)分析表明高温退火后Co基金属接触层中的硅化物更加稳定,接触层下形成的富碳层有效地降低了电子输运的势垒高度,对欧姆接触的形成起了关键作用。通过对Au/Co/C/SiC 欧姆接触的热稳定性测试,结果表明经过500oC下20小时的热测试,掺杂浓度为2.8×1018 cm-3的 n型4H-SiC保持了良好的欧姆特性。
Effects of Cadmium on Growth, Oxidative Stress and Antioxidant Enzyme Activities in Peanut (Arachis hypogaea L.) Seedlings
Shihua Shan,Feng Liu,Chunjuan Chunjuan Li,Shubo Wan
Journal of Agricultural Science , 2012, DOI: 10.5539/jas.v4n6p142
Abstract: The effects of different cadmium (Cd) concentrations on growth, oxidative stress, and antioxidant enzymes activities in peanut seedlings of five cultivars were investigated in Hoagland’s nutrient solution. The results indicated that the growth of seedlings and the maximal photochemical efficiency of Photosystem II were significantly reduced after treatment with 500 ?M Cd2+ for 4 days, but no significant difference was detected when exposed to 10 and 100 ?M Cd2+, with the exception of FH3 being more sensitive to 100 ?M Cd2+. The changes in H2O2 and malondialdehyde contents indicated that Cd2+ stress caused an accumulation of reactive oxygen species and induced oxidative stress when exposed to 100 and 500 ?M Cd2+. The changes in total soluble protein (TSP) content and antioxidant enzyme activities were similar among the five cultivars. However, in the different concentrations of Cd2+, TSP content and antioxidant enzyme activities showed different trends when compared with control groups. Exposure to 100 ?M Cd2+ markedly enhanced activities of four antioxidant enzymes in both shoots and roots of all investigated cultivars. Additionally, cadmium stress had a more severe impact on roots as opposed to shoots of seedlings.
Single Adatom Adsorption and Diffusion on Fe Surfaces  [PDF]
Changqing Wang, Dahu Chang, Chunjuan Tang, Jianfeng Su, Yongsheng Zhang, Yu Jia
Journal of Modern Physics (JMP) , 2011, DOI: 10.4236/jmp.2011.29130
Abstract: Using Embedded-atom-method (EAM) potential, we have performed in detail molecular dynamics studies on a Fe adatom adsorption and diffusion dynamics on three low miller index surfaces, Fe (110), Fe (001), and Fe (111). Our results present that adatom adsorption energies and diffusion barriers on these surfaces have similar monotonic trend: adsorption energies, Ea(110) < Ea(001) < Ea(111), diffusion barriers, Ed(110) <Ed(001) <Ed(111). On the Fe (110) surface, adatom simple jump is the main diffusion mechanism with relatively low energy barrier; nevertheless, adatoms exchange with surface atoms play a dominant role in surface diffusion on the Fe (001).
Comparison Analysis of Core Journals on Technology Foresight Studies between China's and the Other Countries'

LUAN ChunJuan,

中国科技期刊研究 , 2011,
Abstract: 比较国内外技术预见研究的核心期刊分布,对我国技术预见研究具有重要的指导意义。研究结果显示,国际技术预见研究的核心期刊主要是美国、英国、荷兰和瑞士主办或出版的英文期刊,这些期刊专业性比较强,创刊的时间比较早。国际技术预见研究的核心期刊《技术预见与社会变迁》也受到国内技术预见研究者的高度关注和引用,表明了国内学者对国际相同主题研究前沿成果的借鉴和学习。国内技术预见研究的核心期刊包括中文和外文两部分,但与国际比较,国内技术预见研究领域尚缺少专业的“技术预见”核心期刊。随着我国技术预见研究实力的增强,和研究成果的增多,我国政府和有关研究学会等机构也应创办技术预见研究的专业核心期刊。
The research of fuzzy segment query under the spatial database
Guangjun Song,Zhongxiao Hao,Chunjuan Wang
Journal of Computers , 2010, DOI: 10.4304/jcp.5.2.290-297
Abstract: Recently years, the nearest neighbor (N-N) query in the spatial database contracts much public attentions and is studied widely. Because of the kinds of the query objects, there are generally three types, point to point (p-p), point to segment (p-s) and segment to segment (s-s). Most of them are precise data, and related documents are rich. However, the research about querying fuzzy objects with influential region is seldom and the related documents are few. In this paper, we mainly study the N-N query with the fuzzy segment in spatial database. Four located relations based on fuzzy segments are come up with, and we list the N-N algorithm. The experimental result shows high query efficiency.
A Factorial Validation of Knowledge-Sharing Motivation Construct  [PDF]
Qinxuan Gu, Yingting Gu
Journal of Service Science and Management (JSSM) , 2011, DOI: 10.4236/jssm.2011.41009
Abstract: While there is increasingly strategic importance in knowledge, it is facing new challenges to manage knowledge effectively. The paper studies the motivational construct model for knowledge sharing from the perspective of content theories and social motivation theories. The data collected by using the questionnaire survey from a variety of industries was analyzed on the basis of interviews and pretest. The results of exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) showed the motivational construct model for knowledge sharing was comprised of existence motivation, relatedness motivation, growth motivation and norm motivation. The results extended the perspectives for knowledge sharing motivation and provided theoretical evidences for facilitating knowledge sharing behavior.
Large Two-Dimensional Photonic Band-Gaps Designed by Rapid Genetic Algorithms

Gong Chunjuan,Hu Xiongwei,

半导体学报 , 2006,
Abstract: The plane wave expansion method (PWM) and rapid genetic algorithm (RGA) are used to design two-dimensional photonic crystals with large complete band-gaps.The algorithms evolve from randomly generated photonic crystals and integrate a filling fraction controlling operator and Fourier transform data storage mechanism to run efficiently and effectively.The obtained optimal photonic crystal has a large band gap with a relative width of 13.25% and can be easily fabricated due to large pixel.
Mechanical Properties of the TaSi2 Fibers by Nanoindentation

Chunjuan Cui,Jun Zhang,Lin Liu,Hengzhi Fu,

材料科学技术学报 , 2010,
Abstract: The Si-TaSi2 eutectic in situ composite, which has highly-aligned and uniformly-distributed TaSi2 fibers in the Si matrix, can be obtained when the solidification rate changes from 0.3 to 9.0 mm/min. It is very interesting that one or two TaSi2 fibers are curved when the solidification rate reaches 6.0 mm/min, although it is very brittle in general. The formation mechanism of the curved fiber is discussed and mechanical properties of the TaSi2 fibers are examined by nanoindentation. It is found that the hardness and the elastic modulus of the bended TaSi2 fiber are much higher than that of the straight TaSi2 fiber. Moreover, the reasons why the mechanical properties of the straight TaSi2 fiber are different from that of the curved TaSi2 fiber are discussed. This can be ascribed to internal stress which results from mismatch of the thermal expansion coefficients of the two phases and di erent crystallographic orientations.
Study on aerobic co-metabolism biodegradation of aniline in wastewater

Li Jian,Xie Chunjuan,

环境工程学报 , 2007,
Abstract: 微生物共代谢是废水中难降解性有机物生物降解的重要方式.比较了在以苯胺溶液作为惟一碳源与能源和有共代谢底物存在下苯胺的降解过程.结果表明,共代谢显著地提高了苯胺的降解率,在32℃恒温条件下、利用葡萄糖作生长基质、且与苯胺的质量比为1:6、72 h后,苯胺的降解率最高可达75.6%.再加人蛋白胨做氮源后,苯胺的降解率可提高到82.9%,COD的去除率达55.4%.
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