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Surface effects of monolayer-protected gold nanoparticles on the redox reactions between ferricyanide and thiosulfate

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Science China chemistry 2005年第5期48卷 424-430页

作者： LI Di1, SUN Chunyan1, HUANG Yunjie1, LI Jinghong1,2 & CHEN Shaowei3 1. State Key Laboratory of Electroanalytical chemistry, Changchun {1. of Applied chemistry, chinese academy of sciences, Changchun 130022, China 2. department of chemistry, tsinghua university, {1.} {1.}, China 3. department of chemistry, university of California, Santa Cruz, Santa Cruz, CA 95064, USA 1. State Key Laboratory of Electroanalytical chemistry Changchun {1. of Applied chemistry Chinese Academy of Sciences 130022 Changchun China 2. department of {1. Tsinghua University 100084 Beijing China 3. department of {1. University of California 95064 Santa Cruz Santa Cruz CA USA

Electron transfer through the self-assembled monolayers (SAMs) on gold nanopar-ticles is investigated by using the monolayer protected gold nanoclusters (MPCs) as elec-tron-transfer mediators. 3-Mercaptopropionic acid (MPA) and 1.-meraptoundecanoic acid (MUA) MPCs were employed to catalyze the redox reaction between potassium ferricyanide and sodium thiosulfate. The catalytic mechanism was proposed that the MPCs act as diffusing elec-tron-mediators and electron transfers to and from the MPCs surface. Therefore the electron transfer rate through the capping layers would be proportional to the MPCs catalyzed reaction rate, which was monitored by the UV absorbance of ferricyanide. The calculated apparent rate constant was orders of magnitude smaller than that of the maximum of tunneling current, which was attributed to the splited energy level of the nanoscale particles.

关键词： electron transfer, three-dimensional self-assembled monolayers, redox reaction, electron transfer mediator, surface effect.

Hard X-ray lags of Cygnus X-1.on short timescales

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Science China(Physics,Mechanics & Astronomy) 2010年第S1期53卷 150-152页

作者： JIN Jing1,lu Yu2,3,QU Jinlu2 & LI TiPei1,2 1 department of Engineering Physics & Center for Astrophysics,{1. university,beijing 1.0084,China 2 Key Laboratory of Particle Astrophysics,institute of High Energy Physics,chinese academy of sciences,beijing 100049,China 3 Graduate university of chinese academy of sciences,beijing 100049,China 1. department of Engineering Physics & Center for Astrophysics Tsinghua University Beijing 100084 China2. Key Laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China3. Graduate University of Chinese Academy of Sciences Beijing 100049 China

Calculating the time lags over different timescales using the cross-correlation technique may lead to a biased estimate of small *** a timescale for lightcurve binning,we propose to subtract the local average instead of the global average during the cross-correlation,in order to filter variations on timescales larger than the bin *** new method allows us to make an unbiased estimate of the time lags using RXTE/PCA data on timescales as small as-5 ms,where the Fourier technique becomes *** calculate the time lag spectra of Cygnus X-1.at different spectral states with the new method,and find that the source appears to have similar X-ray lags on small timescales independent of its spectral states.

关键词： spectral lags Cygnus X-1 data analysis

Evaluation of non-covalent interaction between Seryl-Histidine dipeptide and cyclophilin A using NMR and molecular modeling

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Science China chemistry 2010年第9期53卷 1987-1993页

作者： LIU Yan1,SHI YanHong2,LIU XiaoXia1,LIN MingKun1,LIN DongHai1,2 & ZHAO YuFen1,3 1Key Laboratory for Chemical Biology of Fujian Province,department of Chemical Biology,department of chemistry,College of chemistry and Chemical Engineering,Xiamen university,Xiamen 361005,China 2Shanghai institute of Materia Medica,Shanghai institutes of Biological sciences,chinese academy of sciences,Shanghai 201203,China 3Key Laboratory for Bioorganic Phosphorus chemistry and Chemical Biology,Ministry of Education,department of chemistry,School of Life sciences and Engineering,{1.} university,{1.} {1.},China 1. Key Laboratory for Chemical Biology of Fujian Province Department of Chemical Biology Department of Chemistry College of Chemistry and Chemical Engineering Xiamen University Xiamen 361005 China2. Shanghai Institute of Materia Medica Shanghai Institutes of Biological Sciences Chinese Academy of Sciences Shanghai 201203 China3. Key Laboratory for Bioorganic Phosphorus Chemistry and Chemical Biology Ministry of Education Department of Chemistry School of Life Sciences and Engineering Tsinghua University Beijing 100084 China

Seryl-Histidine dipeptide(Ser-His) has been previously reported to be capable of cleaving DNAs and carboxyl esters,as well as *** protein cleavage mechanism has not been addressed *** an initial step of protein cleavage activity,the non-covalent binding affinity of Ser-His for proteins is a crucial *** this work,we took cyclophilin A(CyPA) as a substrate protein,and evaluated the non-covalent interaction between CyPA and Ser-His using a combination of NMR spectroscopy and molecular modeling *** independent Ser-His binding sites on CyPA were detected using 1.N-1. heteronuclear single-quantum coherence(HSQC) *** binding site binds one Ser-His *** constants,Kd1.and Kd2,were estimated to be 2.07 and 6.66 mmol/L,respectively,indicative of the weak non-covalent interaction between Ser-His and *** on molecular modeling results,we suggest that both the α-amino and the side chain hydroxyl group of Ser-His are crucial for the non-covalent interaction between Ser-His and *** work sheds light on the molecular mechanism of Ser-His and its analogues cleaving proteins.

关键词： Ser-His cyclophilin A HSQC non-covalent interaction binding sites

Assessment of candidate plant DNA barcodes using the Rutaceae family

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Science China(Life sciences) 2010年第6期53卷 701-708页

作者： luO Kun1,2,CHEN ShiLin1,CHEN KeLi2,SONG JingYuan1,YAO Hui1,MA XinYe1,ZHU YingJie3,PANG XiaoHui1,YU Hua1,LI XiWen1,4 & LIU Zhen2 1institute of Medicinal Plant Development,Peking Union Medical College,{1. academy of Medical sciences,beijing 100193,China 2College of Pharmacy,Hubei university of {1. Medicine,Wuhan 430061,China 3School of Bioscience and Engineering,Southwest Jiaotong university,Chengdu 610031,China 4department of chemistry,{1.} university,beijing {1.},China 1. institute of Medicinal Plant Development Peking Union Medical College Chinese Academy of Medical Sciences Beijing 100193 China2. College of Pharmacy Hubei University of Chinese Medicine Wuhan 430061 China3. School of Bioscience and Engineering Southwest Jiaotong University Chengdu 610031 China4. Department of Chemistry Tsinghua University Beijing 100084 China

DNA barcoding is a rapidly developing frontier technology that is gaining worldwide ***,seven regions (psbA-trnH,matK,ycf5,rpoC1.rbcL,ITS2,and ITS) with potential for use as DNA barcodes were tested for their ability to identify 300 samples of 1.2 species from 72 genera of the family *** evaluate each barcode’s utility for species authentication,PCR amplification efficiency,genetic divergence,and barcoding gaps were *** found that the ITS2 region exhibited the highest inter-specific divergence,and that this was significantly higher than the intra-specific variation in the "DNA barcoding gap" assessment and Wilcoxon two-sample *** ITS2 locus had the highest identification efficiency among all tested *** a previous study,we found that ITS2 was able to discriminate a wide range of plant taxa,and here we confirmed that ITS2 was also able to discriminate a number of closely related ***,we propose that ITS2 is a promising candidate barcode for plant species identification.

关键词： DNA barcoding ITS2 Rutaceae identification

Origin of the Red Earth sequence on the northeastern Tibetan Plateau and its implications for regional aridity since the middle Miocene

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Science China Earth sciences 2006年第5期49卷 505-517页

作者： WANG Xianyan1.7, lu Huayu1.2, JI Junfeg3, WANG Xiaoyong1.7, ZHAO Jingbo4, HUANG Baochun5 & LI Zhen6 1. SKLLQG, {1. of Earth Environment, {1. academy of sciences, Xi’an 71.075, China 2. department of Urban and Resources sciences, Nanjing university, Nanjing 21.093, China 3. department of Earth sciences, Nanjing university, Nanjing 21.093, China 4. department of Geography, Shaanxi Normal university, Xi’an 71.062, China 5. {1. of Geology and Geophysics, {1. academy of sciences, {1.} 1.0029, China 6 department of Geography, Qinghai Normal university, Xining 81.008, China 7. Graduate School of the {1. academy of sciences, {1.} 1.0039, China 1. SKLLQG Institute of Earth Environment Chinese Academy of Sciences Xi’an 710075 China 7. Graduate School of the chinese {1. of sciences Beijing 100039 China 2. department of Urban and Resources {1. Nanjing University Nanjing 210093 China 3. department of Earth {1. Nanjing University Nanjing 210093 China 4. department of Geography Shaanxi Normal University Xi’an 710062 China 5. institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China 6. department of Geography Qinghai Normal University Xining 810008 China

The Red Earth deposit around Xining, northeastern Tibetan Plateau, has beenstudied in terms of soil micro-structure, grain-size distribution, major- and trace-elementchemistry and magne-tostratigraphy. Field investigations indicate that the Red Earth sequenceconsists of 25 visually definable yellow-brown and weakly-developed soils interbedded with reddishstrongly-developed soils, and has a similar structure to the aeolian Red Clay deposit on the {1.Loess Plateau. Grain-size analysis shows that the Red Earth deposit is very fine-grained with anegligible sand fraction ( > 63 μm). Thin-section observations under light microscopy show that thedeposit has a clayey texture and the coarse fraction ( > 1. μm) mainly consists of quartz,feldspar and micas. Pyroxene and hornblende were also observed. This mineralogical composition ofthe coarse fraction is similar to that of the Quaternary loess. In addition, all of the mineralgrains are semi angular semi-angular and are generally finer than 63 μm. There is a good agreementbetween the major and minor trace element chemistry of loess-soil units and the Red Earth *** REE distributions of the loess-soil and the Red Earth deposit are similar in shape, withenriched LREE and fairly flat HREE profiles and a clear negative Eu anomaly. The geochemicalcharacteristics of the Red Earth deposit are also identical to those of upper continental crust,thus indicating a wind-blown origin. Magnetostratigraphic investigation shows that onset of the RedEarth deposition predates 1..4 Ma BP (1..6 Ma at a nearby site). The distribution of the reportedMiocene aeolian loess at Qin''an of the Loess Plateau is still unknown. Our results indicate thatthis aeolian deposit had extended to the northeastern Tibetan Plateau by at least the middleMiocene. The similarity of the element geochemistry between the Red Earth deposit and the overlyingloess shows that they may have similar sources and dynamic transport system, and may indicate thatthe

关键词： Red Earth deposit, Northeastern Tibetan Plateau, aeolian deposit, aridity of Asia, the middle Miocene.

Cocrystal Phenomena of DABCO with Phenol Derivatives

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Chemical Research in chinese Universities 1993年第3期9卷 261-263页

作者： GUO Wen-sheng (department of {1., Liaoning Normal university, Dalian, 1.6022)TIAN Zhi-yue, lu Yang and ZHENG Qi-tai (institute of Meteria Medica, chinese academy of Medical sciences, beijing, 1.0050)

It has been reported that 1.4-diazabicyclo[2,2,2] octane(DABCO) can form complexed crystals with lithium alkals. Our experimental results show that DABCO can also form cocrystals with phenol derivatives such as phenol... 详细信息

关键词： Cocrystal phenomena DABCO Phenol derivatives

Experimental and theoretical study of^(1.)C shielding tensors in new-style molybdenum complex

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Science China chemistry 2004年第3期47卷 214-221页

作者： HOU Guangjin1,2, WANG Liying2, lu Xiaoming3, ZHENG Anmin2, DENG feng2 &YE Chaohui1,2 1. {1. of Physics, Huazhong university of Science and Technology, Wuhan 430074, China 2. State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan institute of Physics and Mathematics, Chi-nese academy of sciences, Wuhan 430071, China 3. {1. of chemistry, Capital Normal university, beijing 100037, China 1. department of Physics Huazhong University of Science and Technology 430074 Wuhan China 2. chinese {1. of sciences State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics Wuhan Institute of Physics and Mathematics 430071 Wuhan China 3. department of {1. Capital Normal University 100037 Beijing China

1.C 2D-PASS spectra of two new cis-dioxo catecholatomolybdenum complexes (NH2CH2NH2CHCH2)2(H+)3[MovO 2(C6H4O2)2] and (NH2CH2CH2CH2NH2)2(H+)3[Mo(v)O2 (C2H2O2)2] have been obtained by solid-state nuclear magnetic resonance (NMR), in which the spinning sidebands were well-separated. The principal components of the 1.C shielding tensors were extracted by theoretically fitting the intensities of 1.C spinning sidebands. The effects of counter cations on 1.C chemical shift isotropy and shielding tensor of cis-dioxo catecholatomolybdenum complex anion [Mo (v)O2(C6H4O2)2]3? were studied, comparing the 1.C CSA of those carbon sites in complex anions with that of the counter cations. Based on the known structure of the molybdenum complex crystal, theoretical values of 1.C shielding tensors were calculated by the ainitio GIAO method, in comparison with the experimental results.

关键词： NMR, magic angle spinning, chemical shift anisotropy, shielding tensor, cis-dioxo-monomolybdenum.

x-ray Crystal Structure of a Dinuclear Zinc(Ⅱ) Complex with Unusual Two Monodentate O-coordination of Carboxylate Group of Isonicotinate

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chinese Chemical Letters 1998年第9期9卷 881-884页

作者： feng Mei NIE Ru Ji WANG Yan Mei LI Yu Fen ZHAO (Bio-organic Phosphorus {1. Laboratory, department of {1.,tsinghua university, beijing, 1.0084)Munirathinam NETHAJI Akhil R. CHAKRAVARTY (department of Inorganic and Physical {1., Ind Bio-Organ. Phosphorus Chem. Lab. Department of Chemistry Tsinghua University Beijing 100084 China department of Inorganic {1. Indian Institute of Science Bangalore 560 012 India

Reaction of Zn(ClO4)2·6H2O with septadentate 2,6-bis[bis(2-benzimidazolylme-thyl)amino methyl]-4-methylphenol (Hbbap) and sodium isonicotinate yielded a dinuclear zinc complex[Zn2(bbap) (Iso) (Hiso)] (ClO4)2·[Zn2 (bbap) (Iso) (H2O)] (ClO4)2·4H2O(1.·1.·4H2O). Hiso isisonicotinic acid and Iso is isonicotinate anion. The structure has been established by X-raycrystallography and shows that the two zinc ions are bridged by the phenoxy unit of bbap- ligand,and the presence of unusual monodentate O-coordination of carboxylate group from isonicotinicacid. The coordination geometry around the zinc ion is approximately trigonal bipyramidal.

关键词： zinc complex isonicotinate metalloenzyme crystal structure

Removal of Volatile Organic Compounds by Adsorption and Photocatalytic Oxydation

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Journal of Wuhan university of Technology(Materials Science) 2007年第3期22卷 450-452页

作者：许德平黄正宏 Lab of Advanced Materials Department of Materials Science and EngineeringTsinghua University School of Chemical and Environmental Engineering China University of Mining and Technology

Based on the study of equilibrium adsorption on viscose rayon-based activated carbon fiber （ACF） by gravimetric method, mounting of TiO2 on PAN-based activated carbon cloth （ACC） and their photocatalytic activity as well as adsorption performance for benzene were investigated. The crystallinity of TiO2 and pore structure were characterized by XRD and N2 adsorption. The results show that crystallinity of TiO2 and pore structure could be postulated by heat treatment condition. Both crystallinity of TiO2 and pore structure of hybrid have effects on photocatalytic performance of TiO2-mounted ACC. It would be more attractive and prospective for the combination of TiO2 photocatalytic activity and adsorption ability of porous materials.

关键词： volatile organic compounds activated carbon cloth TiO2