检索结果-南通市图书馆

Development of a high-throughput assay for the HIV-1 integrase disintegration reaction

在线全文

学校读者我要写书评

暂无评论

science china(Life sciences) 2010年第2期53卷 241-247页

作者： HE HongQiu,LIU Bin,ZHANG XiaoYi,CHEN WeiZu & WANG CunXin college of Life science and Bioengineering,beijing university of technology,beijing 100124,china college of Life science and Bioengineering Beijing University of Technology

Both HIV-1 integrase (IN) and the central catalytic domain of IN (IN-CCD) catalyze the disintegration reaction in *** this study,IN and IN-CCD proteins were expressed and purified,and a high-throughput format enzyme-linked immunosorbent assay (ELISA) was developed for the disintegration *** exhibited a marked preference for Mn2+ over Mg2+ as the divalent cation cofactor in ***,a known IN inhibitor,was found to be an IN-CCD *** assay is sensitive and specific for the study of disintegration reaction as well as for the in vitro identification of antiviral drugs targeting IN,especially targeting IN-CCD.

关键词： HIV-1 integrase IN-CCD disintegration high-throughput assay

Cloning, sequencing and identification of single nu-cleotide polymorphisms of partial sequence on the porcine CACNA1S gene

在线全文

学校读者我要写书评

暂无评论

science china(Life sciences) 2008年第4期51卷 317-325页

作者： FANG XiaoMin1,2, XU NingYing2 & REN ShouWen1 1 Institute of animal science, Jiangsu Academy of agricultural sciences, Nanjing 210014, china 2 college of animal science, Zhejiang university, Hangzhou 310029, china Institute of animal science Jiangsu Academy of Agricultural Sciences Nanjing China college of animal science Zhejiang University Hangzhou China

CACNA1S gene encodes the α1 subunit of the calcium channel. The mutation of CACNA1S gene can cause hypokalemic periodic paralysis (HypoKPP) and maliglant hyperthermia synarome (MHS) in hu-man beings. Current research on CACNA1S was mainly in human being and model animal, but rarely in livestock and poultry. In this study, Yorkshire pigs (23), Pietrain pigs (30), Jinhua pigs (115) and the second generation (126) of crossbred of Jinhua and Pietrain were used. Primers were designed ac-cording to the sequence of human CACNA1S gene and PCR was carried out using pig genome DNA. PCR products were sequenced and compared with that of human, and then single nucleotide poly-morphisms (SNPs) were investigated by PCR-SSCP, while PCR-RFLP tests were performed to validate the mutations. Results indicated: (1) the 5211 bp DNA fragments of porcine CACNA1S gene were ac-quired (GenBank accession number: DQ767693 ) and the identity of the exon region was 82.6% be-tween human and pig; (2) fifty-seven mutations were found within the cloned sequences, among which 24 were in exon region; (3) the results of PCR-RFLP were in accordance with that of PCR-SSCP. Ac-cording to the EST of porcine CACNA1S gene published in GenBank (Bx914582, Bx666997), 8 of the 11 SNPs identified in the present study were consistent with the base difference between two EST frag-ments.

关键词： pig calcium channel α1 subunit (CACNA1S) single nucleotide polymorphism (SNP) PCR-SSCP PCR-RFLP

Interface-directed sol-gel:direct fabrication of the covalently attached ultraflat inorganic oxide pattern on functionalized plastics

在线全文

学校读者我要写书评

暂无评论

science china Chemistry 2010年第1期53卷 173-182,287-288页

作者： GAN ShengHua,YANG Peng & YANG WanTai State Key Laboratory of Chemical Resource Engineering college of Materials science and Engineering,beijing university of Chemical technology,beijing 100029,china State Key Laboratory of Chemical Resource Engineering college of Materials science and Engineering Beijing University of Chemical Technology Beijing China

For plastic electronics and optics,the fabrication of smooth,transparent and stable crack-free inorganic oxide films(and patterning) on flexible polymeric substrates with strong bonding strength and controllable thickness from nanometers to micrometers is a key but still remains a *** versatile inorganic oxides,silica oxide film as SiOx is especially important because this semiconductor material could provide crucial properties in devices or serve as a base layer for further multilayer *** this paper,we describe a new interface-directed sol-gel method to fabricate flexible high quality silicon oxide film onto commodity *** resulting crack-free silica film has strong covalent bonding with polymer substrates,homogeneous morphology with ultralow roughness,highly optical transparency,tunable thickness from nm to μm,and easy patterning *** fabrication strategy relies on a novel photocatalytic oxidation reaction by photosensitive ammonium persulfate(APS),which is able to fabricate highly reactive hydroxyl monolayer surface on inert polymeric *** kind of hydroxylated surface could serve as nucleation and growth sites to initiate surface sol-gel *** a result,well-defined SiOx film deposition(gelation) occurs,and patterned hydroxylation regions could be easily utilized to induce the formation of patterned oxide film *** strategy also excludes the requirements of clean room and vacuum devices so as to fulfill low-cost and fast fabrication *** application examples from such high quality SiOx layer onto plastics are given but should not be limited within *** is that oxygen permeation rate of SiOx deposited polymer film decreases 25 times than pristine polymer substrate,which is good for the potential packaging *** other one is that silanization monolayer,for example,3-aminopropyltriethoxysilane(APTES),could be successfully constructed onto silica layer through classical silanization reac

关键词： surface patterning silicon oxide sol-gel polymer surface modification functional coatings

SYNTHESIS AND PROPERTIES OF NEW MESOGEN-JACKETED LIQUID CRYSTALLINE POLYMERS

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer science 2000年第2期18卷 139-148页

作者： Qi-ding Mi Qi-feng Zhou Department of Polymer science & Engineering, college of Chemistry Peking university, beijing 100871, china 北京大学北京

Some new mesogen-jacketed liquid crystalline polymers (MJLCP) with polymer backbones, spacers, and mesogenic units of different structures were synthesized by radical polymerization. The mesomorphic behavior of these polymers was examined using differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). Their liquid crystallinity is influenced by the variation of polymer backbone, spacer, mesogenic unit and its terminal groups. The results show that 1) a more flexible polymer main-chain is more favorable to the formation of a liquid crystal phase, while 2) a flexible spacer will decrease the 'Jacket Effect' and the liquid crystallinity and 3) a subtle modification of the terminal groups on the mesogenic unit may also have a significant influence on properties of the polymers.

关键词： mesogen-jacketed liquid crystalline polymers polymer backbones spacers mesogenic units liquid crystallinity

Electronic structure and magnetism of Fe-doped SiC nanotubes

在线全文

学校读者我要写书评

暂无评论

science china(Physics,Mechanics & Astronomy) 2010年第9期53卷 1582-1589页

作者： ZHANG WeiHu1,2,3,ZHANG FuChun3,ZHANG ZhiYong4,LU ShuYuan5 & YANG YanNing3 1 Xi’an Institute of Optics and Precision Mechanics,Chinese Academy of sciences,Xi’an 710068,china 2 Graduate university of Chinese Academy of sciences,beijing 100049,china 3 college of Physics and Electronic Information,Yan’an university,Yan’an 716000,china 4 Information science and technology Institution,Northwest university,Xi’an 710127,china 5 Department of Telecommunications,Xi’an Institute of Posts and Telecommunications,Xi’an 710121,china Xi"an Institute of Optics and Precision Mechanics Chinese Academy of Sciences Graduate university of Chinese Academy of sciences college of Physics and Electronic Information Yan"an University Information science and technology Institution Northwest

The electronic structure and magnetic properties of Fe-doped SiC nanotubes are investigated by using the first-principles method based on density functional theory(DFT) in the local spin density approximation(LSDA).The calculation results indicate that the SiC nanotube of Fe substitution for C exhibits antiferromagnetism while ferromagnetism features prominently when Fe substitutes *** is a kind of half-metal magnetic *** formation energy calculation results show that the formation energy of ferromagnetic structure is 3.2 eV lower than that of antiferromagnetic *** atoms are more likely to replace Si ***-orbit coupling induces electron spin polarization in the ground ***,the doping Fe atoms make relaxation towards the outside of the tube to some extent and larger geometric distortion occurs when Fe substitutes C,but the whole geometric structure of SiC nanotubes is not damaged due to the *** is revealed in the calculation of energy band structure and density of states that more dispersed distribution of energy levels is produced near the Fermi *** Fe substitution for Si,obviously there are spin-split and intense p-d hybrid effects by Si 3p electron spins and Fe 3d electron spins localized at the exchanging interactions between magnetic transitional metal(TM) *** electronic density results indicate that system magnetic moments are mainly generated by the unpaired 3d electrons of Fe *** these results show that the transition metal doping SiC nanotube could be a potential route to fabricating the promising magnetic materials.

关键词： SiC nanotube the first-principles doped magnetic properties

Reduced analysis and confirmatory research on co-adaptability theoretical solution to conflicting events in construction engineering projects

在线全文

学校读者我要写书评

暂无评论

science china(Technological sciences) 2010年第2期53卷 480-485页

作者： HOU XueLiang1 , LU Mei2 & WANG Kai3 1 School of Business Administration, North china Electric Power university, beijing 102206, china 2 Department of Construction Management, Tsinghua university, beijing 100084, china 3 college of Management, beijing Jiaotong university, beijing 100084, china School of Business Administration North China Electric Power University Beijing China Department of Construction Management Tsinghua University Beijing China college of Management Beijing Jiaotong University Beijing China

The co-adaptability theoretical solution to conflicting events in construction engineering projects has three problems. First, the transformation of constraint conditions of theoretical solution is very difficult in practical engineering applications; second, some coefficients are difficult to be determined; third, there are overfull circular arithmetic operations involved in it. To resolve these problems, a new method to reduce the theoretical solution complications is proposed. By analyzing the operating mechanism of theoretical solution model, redundancies in the theoretical solution can be eliminated, and the ISM mapping with the co-adaptability solution can be set up. Based on this approach, a procedure to solve practical conflicting events in construction projects is established by replacing characteristic variables with mathematic variables. The research results show that the procedure can replace the co-adaptability theoretical solution effectively and solve practical conflicting events in construction projects.

关键词： construction project conflict theoretical solution reduced analysis ISM confirmatory research

Protective Effects of Vitamin E against Oxidative Damage Induced by Aβ(1-40)Cu(Ⅱ)Complexes

在线全文

学校读者我要写书评

暂无评论

Acta Biochimica et Biophysica Sinica 2007年第2期39卷 123-130页

作者： Xueling DAI~1 Yaxuan SUN~2 and Zhaofeng JIANG~2 ~1college of Life science,Capital Normal university,Bejing 100037,china ~2college of Applied sciences Humanities of beijing Union university,beijing 100083,china college of Life science Capital Normal UniversityBeijing 100037 China college of Applied sciences and Humanities of beijing Union universitybeijing 100083 China

β-amyloid peptide （Aβ） is considered to be responsible for the formation of senile plaques,which is the hallmark of Alzheimer's disease （AD）.Oxidative stress,manifested by protein oxidation andlipid peroxidation,among other alterations,is a characteristic of AD brain.A growing body of evidence hasbeen presented in support of Aβ1-40forming an oligomeric complex that binds copper at a CuZn superoxidedismutase-like binding site. Aβ1-40Cu（Ⅱ） complexes generate neurotoxic hydrogen peroxide （H2O2） from O2via Cue+ reduction,though the precise reaction mechanism is *** toxicity of Aβ1-40or the Aβ1-40Cu（Ⅱ）complexes to cultured primary cortical neurons was partially attenuated when （+）-α-tocopherol （vitamin E）as free radical antioxidant was added at a concentration of 100 μ*** data derived from lactate dehydro-genase （LDH） release and the formation of H2O2confirmed the results from the MTT *** findingsindicate that copper binding to Aβ1-40can give rise to greater production of H2O2, which leads to a break-down in the integrity of the plasma membrane and subsequent neuronal *** treated with vitaminE exhibited much slighter damage,suggesting that vitamin E plays a key role in protecting neuronal cellsfrom dysfunction or death.

关键词： Aβ1-40Cu(II)complex vitamin E neuronal oxidative damage H2O2 generation lactate dehydrogenase(LDH)release

Enhancement of monacolin K production via intergeneric protoplast fusion between Aspergillus terreus and Monascus anka

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Progress in Natural science:Materials International 2007年第6期17卷 703-707页

作者： Chen Zhi, Lin Wen, Yu Ping and Song Yuan(Department of Microbiology, college of Biological sciences, china agricultural university, beijing 100094, china) Department of Microbiology College of Biological Sciences China Agricultural University Beijing 100094 China

Intergenric protoplast fusion between Aspergillus terreus CA99 and Monascus anka M-3, the high and low producers of monacolin K respectively,was performed for enhancement of monacolin K production. The 24-hour-old mycelia of A. terreus CA99 and M. anka M-3 were treated with 0.5% lywallzyme, 0.3% snailase and 0.3% cellulase at 34℃ for 5 h and at 30℃ for 3.5 h, and their protoplasts formation reached 1.76×107/mL and 1.68×107/mL respectively. Parental protoplasts were irradiated with a 30 W UV light away from 30 cm for 3 min and then mixed. The mixture was incubated with 30% PEG 6000 for 15 min. The reviving fusants were isolated on the regeneration plates. Of the 363 fusants isolated, over 100 showed enhanced monacolin K production compared with the parental strain M. anka M-3. Ten of them produced monacolin K about 1.6-fold of that *** M-3 does and the monacolin K titer of two fusants (F49 and F104) increased by about 1-fold. The monacolin K yields of F49 and F104 were 460 μg/mL and 457 μg/mL respectively. In optimized fermentation medium, the monacolin K titer of F49 reached 1216 μg/mL.

关键词： monacolin K Monascus anka Aspergillus terreus protoplast fusion fermentation.

A new method of ionospheric-free hybrid differential positioning based on a double-antenna CAPS receiver

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

science china(Physics,Mechanics & Astronomy) 2009年第3期52卷 368-375页

作者： GUO JinYun1,2, HAN YanBen1 & CHANG XiaoTao3 1 National Astronomical Observatories, Chinese Academy of sciences, beijing 100012, china 2 college of Geodesy and Geomatics, Shandong university of science and technology, Qingdao 266510, china 3 Chinese Academy of Surveying and Mapping, beijing 100039, china National Astronomical Observatories Chinese Academy of Sciences Beijing China college of Geodesy and Geomatics Shandong University of Science and Technology Qingdao China Chinese Academy of Surveying and Mapping Beijing China

Chinese Area Positioning System (CAPS) is a transmitted satellite navigation system moved by the Chinese Academy of sciences. Three basic modes of navigation and positioning with CAPS are given, and then a comparative analysis is made in this paper. In terms of the principle that the ionospheric delay is at an inverse ratio to the frequency square, a new ionospheric-free positioning method based on a double-antenna CAPS receiver is put forward. Then the hybrid differential observations and the solving equations and algorithms for one epoch and multi epochs are deduced according to the basic principle of the method. The method may remove the global errors in signal emission, propagation, transmission and receiving (e.g., ionospheric delay, hardware delay, and clock error). So it is very convenient for the single-epoch solution and multi-epoch navigation and positioning, and may efficiently improve the precision of real time CAPS navigation. Furthermore, the method can be used not only for the geometric orbit determination of CAPS GEO and IGSO satellites and the navigation and positioning, but also for the estimation of the tropospheric zenith delay, which is useful for the study of water vapor changes in the atmosphere. Polynomials are used in this method to express the tropospheric zenith delay and CAPS satellite orbits within the limited time interval, which reduces the num- ber of unknown parameters and thus speeds the computation.

关键词： Chinese Area Positioning System (CAPS) ionospheric-free linear combination double-antenna receiver hybrid differential positioning method