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Synthesis and characterization of a pH-sensitive shielding system for polycation gene carriers

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Science china chemistry 2010年第3期53卷 502-507页

作者： XIA JiaLiang1,2,CHEN Jie1,TIAN HuaYu1 & CHEN XueSi1 1Key Laboratory of Polymer Ecomaterials changchun institute of applied chemistry,chinese academy of sciences,changchun 130022,china 2graduate university of chinese academy of sciences,beijing 100049,china Key Laboratory of Polymer Ecomaterials changchun institute of applied chemistry Chinese Academy of Sciences Changchun China graduate university of chinese academy of sciences Beijing China

To increase the in vivo stability of polycation gene carriers,a pH-sensitive shielding system,γ-benzyl L-glutamate-co-glutamate acid polymer(PGA(60)(60 refers to the molar ratio of glutamate acid in the polymer)),was synthesized and ***(60) showed pH sensitivity at about pH ***(60) shielded the positive charge of DNA/PEI(1:1) *** retardation assay showed that no DNA-strand exchange with PGA(60) occurred after PGA(60) was added to DNA/PEI complexes at different *** cytotoxicity tests demonstrated that neither PGA(60) nor DNA/PEI/PGA(60) ternary complexes had cytotoxicity at the test *** transfection efficiency was improved when the positive charge was partly shielded by PGA(60).Because of the charge repulsion between the surface of cells and ternary complex particles,there was almost no transfection efficiency when the zeta potential of ternary complexes turned to *** of the suitable pH sensitive range,PGA(60) may be a potential shielding system for polycation gene carriers to be used in vivo.

关键词： gene delivery shielding system pH-sensitive polyglutamate

Bioreducible crosslinked low molecular weight branched PEI-PBLG as an efficient gene carrier

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Science china chemistry 2010年第12期53卷 2490-2496页

作者： GUO ZhaoPei 1,TIAN HuaYu 1,XIA JiaLiang 1,2,CHEN Jie 1,LIN Lin 1 & CHEN XueSi 1 1 Key Laboratory of Polymer Ecomaterials changchun institute of applied chemistry,chinese academy of sciences,changchun 130022,china 2 graduate university of chinese academy of sciences,beijing 100049,china Key Laboratory of Polymer Ecomaterials changchun institute of applied chemistry Chinese Academy of Sciences Changchun China graduate university of chinese academy of sciences Beijing China

Low molecular weight polyethylenimine-poly(gamma-benzyl L-glutamate) (PEI-PBLG) was crosslinked by N,N'-cystaminebisacrylamide (CBA) to get the polymer named as CBA-PEI-PBLG (CPP).CPP not only inherits PEI-PBLG's amphiphilic advantages,but also possesses reducible *** can complex with DNA to form ***/DNA complex particles were characterized by particle size and zeta potential *** result showed that the complex particles have suitable size and surface charges for gene *** gel retardation assay also prove CBA-PEI-PBLG has proper condensing ability for *** has good reducible property,and also has good biocompatibility because of introducing PBLG *** cytotoxicity of CPP was evaluated using MTT assay,and the results showed CPP has lower cytotoxicity compared with PEI 25 *** transfection properties were characterized in different cells by using plasmid DNA as a *** showed higher transfection efficiencies and lower cytotoxicity in HeLa *** was attributed to bioreducible and biocompatibility properties of the *** results suggested that CPP is a promising low-toxic,highly effective non-viral gene carrier.

关键词： gene carrier transfection cytotoxicity crosslinked

Synthesis,characterization,properties and crystal structure of heterometallic 1D coordination polymers {[CuLZn·CuLZn(H_2O)]·H_2O}_n

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Science china chemistry 2006年第4期49卷 338-344页

作者： TAO Ruojie1, LI Fu’an1, ZANG Shuangquan1, CHENG Yanxiang2 & NIU Jingyang1 1. chemistry and Chemical Engineering College of Henan university, Kaifeng 475001, china 2. changchun institute of applied chemistry, chinese academy of sciences, changchun 130022, china chemistry and Chemical Engineering College of Henan university Kaifeng China changchun institute of applied chemistry Chinese Academy of Sciences Changchun China

Copper-zinc heterometallic 1D chain coordination polymer has been synthesized and characterized by elemental analysis, and IR spectra etc. The crystal structure was determined by single-crystal X-ray diffraction analyses. The title complex is 1D chain coordination polymer with the chemical formula {[CuLZn·CuLZn(H2O)]·H2O}n, where H4L=N-(2-hydroxybenzamido)-N’-(3-carboxy- lsalicylidene)ethylenediamine. Its structural unit is comprosed of two tetranuclear cycles formed by two dissymmetrical tetranuclear units. These units polymerized each other to form 1D chain coordi- nation polymer.

关键词： copper, zinc, heterometallic coordination polymer, crystal structure.

NEW OPTICALLY ACTIVE AROMATIC POLYIMIDES Ⅱ: SYNTHESIS AND PROPERTIES OF OPTICALLY ACTIVE AROMATIC POLYIMIDE BASED ON (R)-(+)-2, 2′-BIS (2-TRIFLUORO-4-AMINOPHENOXY)-1, 1′-BINAPHTHYL

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chinese Journal of Polymer Science 1999年第1期17卷 87-90页

作者： Qi-ding Mi Yu Ma Lian-xun Gao Meng-xian Ding changchun institute of applied chemistry, chinese academy of sciences changchun 130022, china Department of chemistry, Peking university, beijing 100871 中科院长春应用化学所吉林长春 130022 中科院长春应用化学所吉林长春

Optically active (R)-(+)-2, 2' -bis(2 -trifluoro-4 -aminophenoxy)- 1, 1' -binaphthyl was prepared from1, 1'-bi-2-naphthol. The optically active aromatic polyimide was also successfully synthesized. This newpolymer has good solubility, thermal stability etc. Its specific rotation was found to be +174°, and itschiroptical property was also studied.

关键词： Optical activity 1, 1′-Bi-2-naphthol, Polyimide

Effects of the grain size distribution on the temperature-dependent magnetic susceptibility of magnetite nanoparticles

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Science china Earth sciences 2010年第7期53卷 1071-1078页

作者： ZHAO XiangYu1,2 & LIU QingSong1 1 Paleomagnetism and Geochronology Laboratory (SKL-LE), institute of Geology and Geophysics, chinese academy of sciences, beijing 100029, china 2 graduate university of chinese academy of sciences, beijing 100049, china Paleomagnetism and Geochronology Laboratory (SKL-LE) Institute of Geology and Geophysics Chinese Academy of Sciences Beijing China graduate university of chinese academy of sciences Beijing China

Magnetite is an important magnetic remanence carrier in natural samples and therefore is of great interest in paleo-, rock-, and environmental magnetism. The magnetic properties of magnetite depend on many factors, e.g., concentration and grain size distribution (GSD). In this study, we theoretically investigated the temperature-dependent susceptibility (TDS) of magnetite nanoparticles with a lognormal GSD. Results show that the TDS is affected highly by the GSD mainly in three aspects. Firstly, the unblocking process becomes smoother with the increase of distribution width, characterizing as a wider Hopkinson peak on the TDS curve. Secondly, the blocking temperature increases with the increase of the median diameter or/and the distribution width. Thirdly, the maximum susceptibility decreases with the increase of distribution width, and has a logarithmic function relation with the standard deviation of the distribution. As a case study, this model was further applied to the thermal products of the chinese loess/paleosol samples to determine the granulometry of newly-formed magnetite upon heating based on TDS curves. The results demonstrate the fidelity and feasibility of this method to determine the GSD of nano-sized magnetic particles.

关键词： Néel theory temperature dependence of susceptibility grain size distribution

Highly stereospecific polymerization of isoprene with homogeneous binary Ziegler-Natta catalysts based on NCN-pincer neodymium precursor

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Science china chemistry 2010年第8期53卷 1641-1645页

作者： LIU DongTao1,2,CUI DongMei1 & GAO Wei3 1State Key Laboratory of Polymer Physics and chemistry changchun institute of applied chemistry,chinese academy of sciences,changchun 130022,china 2graduate university of chinese academy of sciences,beijing 100039,china 3School of chemistry,Jilin university,changchun 130012,china State Key Laboratory of Polymer Physics and chemistry changchun institute of applied chemistry Chinese Academy of Sciences Changchun China graduate university of chinese academy of sciences Beijing China School of chemistry Jilin University Changchun China

The aryldiimine NCN-pincer stabilized neodymium dichloride combined with aluminum alkyls established a new type of homogeneous binary neutral Ziegler-Natta catalyst *** system exhibited high activity and high cis-1,4 selectivity for the polymerization of isoprene (Tp=20 °C,98.2%;Tp=-20 °C,> 99%).Such catalytic performances remained under a broad range of polymerization temperatures and monomer-to-neodymium ratios (from 500 to 8000),reaching high number-average molecular weight (Mn=1582 kg/mol) and relatively narrow molecular weight distribution (PDI=1.68),which was,however,influenced by the amount and bulkiness of aluminum *** investigation of the polymerization was performed,which showed the number-average molecular weight of the resultant polyisoprene had an almost linear correlation with the conversion,suggesting,in some degree,the polymerization with this catalytic system was controllable.

关键词： neodymium cis-1 4 selectivity NCN-pincer complex polyisoprene

Modeling diameter distribution of the broadleaved-Korean pine mixed forest on Changbai Mountains of china

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Science china(Technological sciences) 2006年第z1期49卷 177-188页

作者： WANG Shunzhong, DAI Limin, LIU Guohua, YUAN Jianqiong, ZHANG Hengmin & WANG Qingli institute of applied Ecology, chinese academy of sciences, Shenyang 110016, china graduate university of chinese academy of sciences, beijing 100039, china State Key Lab of Systems Ecology, Research Center for Eco-Environmental sciences, chinese academy of sciences, beijing 100085, china institute of applied Ecology Chinese Academy of Sciences graduate university of chinese academy of sciences

The broadleaved-Korean pine mixed forest is a native vegetation in the Changbai Mountains, northeast china. The probability density functions including the normal, negative exponential, Weibull and finite mixture distribution, were used to describe the diameter distributions of the species groups and entire forest stand. There is a strong correlation between parameters and mean DBH except the shape parameters in the mixture distribution. The diameter classes of species and entire forest stand showed not negative exponential but normal and "S" distribution. The mixture function was better than normal and Weibull to describe the model distribution. The location parameter had an effect on the estimated frequency in the first diameter class, when the estimated location parameter was bigger than the lower limit of the first diameter class.

关键词： broadleaved-Korean pine mixed forest, diameter distribution, finite mixture distribution.

Cleaning of Chromate Manufacture Process

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International Journal of Minerals,Metallurgy and Materials 2000年第2期14卷 132-134页

作者： Xing Zou Yi Zhang(applied Science School, university of Science and Technology beijing, beijing 100083, china)(institute of Engineering chemistry and Metallurgy, chinese academy of sciences, beijing 100080, china) applied Science School University of Science and Technology Beijing Beijing 100083 China institute of Engineering chemistry and Metallurgy Chinese Academy of Sciences Beijing 100080 China

Sodium chromate solubility is determined in the range of NaOH concentrations from 450 to 810 g/L andsolution temperatUres from 30 to 110℃. The optimized conditions to separate sodium chromate from NaOH inleached solution are resolved. It is first found the method to efficiently separate sbdium chromate from NaOH andsodium altuninate in crude sodium chromate. Bench-scale studies on the separating are performed. Finally, goodseparation results are achieved.

关键词： chromate separation clean process

Evaluation of 10 plant barcodes in Bryophyta (Mosses)

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Journal of Systematics and Evolution 2010年第1期48卷 36-46页

作者： 1,2 Yan LIU 3 Hai-Fei YAN 4 Tong CAO 3 Xue-Jun GE 1(institute of applied Ecology, chinese academy of sciences, Shenyang 110016, china) 2(graduate university of the chinese academy of sciences, beijing 100049, china) 3(Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South china Botanical Garden, chinese academy of sciences, Guangzhou 510650, china) 4(College of Life & Environment sciences, Shanghai Normal university, Shanghai 200234, china) (institute of applied Ecology Chinese Academy of Sciences Shenyang 110016 China) (graduate university of the chinese academy of sciences Beijing 100049 China) (Key Laboratory of Plant Resources Conservation and Sustainable Utilization South China Botanical Garden Chinese Academy of Sciences Guangzhou 510650 China) (College of Life & Environment sciences Shanghai Normal University Shanghai 200234 China)

DNA barcoding is a molecular tool that uses a standardized DNA region to identify *** preliminary study reported here is the first attempt to specifically focus on universality and attributes of candidate barcodes across a wide systematic range of *** tested eight previously proposed plant barcoding regions(atpF-atpH, ITS2, matK, psbK-psbI, rbcL, rpoB, rpoC1, and trnH-psbA) and two popular phylogenetic markers(rps4 and trnL-trnF of cpDNA) in 49 moss species and 9 liverwort species, representing half of the orders in moss *** ITS2, rbcL, rpoC1, rps4, trnH-psbA and trnL-trnF regions showed good universality, and therefore the efficacy of these loci as DNA barcodes was further evaluated in 36 mosses and 2 liverworts, each of which included two to three individuals per *** five loci, ***, rpoC1, rps4, trnH-psbA and trnL-trnF, were easy to amplify and sequence and showed significant inter-specific genetic variability, making them potentially useful DNA barcodes for *** best performing single loci were the rbcL and rpoC1 coding *** loci showed equivalent performance and combinations of them did not greatly increase their discrimination *** addition, phylogenies generated from each of the separate regions and multi-locus combinations by using best-fit and Kimura 2-parameter models were compared, but no significant difference was found.

关键词： Bryophyta DNA barcoding rbcL rpoC1 rps4 trnH-psbA trnL-trnF.