A Biocompatible Gadolinium(Ⅲ)-Poly(Aspartic Acid-Co-Phenylalanine) for Liver Magnetic Resonance Imaging Contrast Agent

一种新型的以天门冬氨酸-苯丙氨酸共聚物为载体的大分子生物相容性材料(AP-EdA-dOTA-gd)被制备出来作为磁共振成像造影剂.首先合成了天门冬氨酸-苯丙氨酸共聚物,之后利用乙二胺将1,4,7,10-四氮杂环十二烷-1,4,7,10-四乙酸(dOTA)连接到共聚物上,最后将钆离子通过配位的作用方式连接到dOTA上,最终得到大分子AP-EdA-dOTA-gd.体外溶血性试验表明AP-EdA-dOTA-gd具有较好的血液相容性.在P H=5.5的组织蛋白酶b的磷酸缓冲液中,AP-EdA-dOTA-gd能够降解.APEdA-dOTA-gd的体外弛豫效率(15.95 MMOl–1·l·S–1)为目前临床应用的gd-dOTA(5.59MMOl–1·l·S–1)的2.9倍.大鼠肝脏成像实验结果表明,AP-EdA-dOTA-gd对于肝组织的成像增强对比度为63.5±6.1%远高于gd-dOTA(24.2±2.9%).A new biocompatible gadolinium(III)-macromolecule(AP-EDA-DOTA-Gd) was developed as a magnetic resonance imaging(MRI) contrast agent.Poly(aspartic acid-cophenylalanine) was synthesized, modified via ethylenediamine, conjugated with 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid(DOTA) and finally chelated gadolinium(III), yielding gadolinium(III)-based macromolecule(AP-EDA-DOTA-Gd).The hemolytic tests showed the hemocompatibility of this gadolinium(III)-based macromolecular conjugate.In vitro, AP-EDA-DOTA-Gd could be degraded, when it was incubated with cathepsin B in phosphate buffered solution(p H = 5.5).The T1-relaxivity(15.95 mmol–1·L·s–1) of AP-EDA-DOTA-Gd was 2.9 times of that(5.59 mmol–1·L·s–1) of the clinical MRI contrast agent(Gd-DOTA) at 1.5 T and 25 ℃.The liver enhancement of AP-EDA-DOTA-Gd was 63.5±6.1% during the maximum enhancement time(50-80 min), which was much better than that of Gd-DOTA(24.2±2.9%, 10-30 min).AP-EDA-DOTA-Gd was expected to be a potential liver MRI contrast agent.TheNationalNaturalScienceFoundationofChina(20975097and21305134

Conceptual design of clean separation of ternary mixture of acetone-tetrahydrofuran-water

Based on the thermodynamics analysis of the mixture of acetone, tetrahydrofuran (THF) and water, the conceptual design of a clean separation process for this mixture was developed. Extractive distillation was used to separate water from the other two components. Different extractive solvents were compared through simulation with Aspen plus and it was found that triethylene glycol (TEG) was a highly selective and energy saving solvent.The extracted water could be separated from extractive solvent by ordinary distillation. The simulation result s f rom Aspen plus showed that the separation of THF and acetone could be achieved by azeot ropic distillation using cyclohexane or carbon bisulfide ( CS2 ) as azeot ropic solvent according to different end requirement s. When CS2 was used as azeot ropic solvent, high purity THF could be obtained while accompanied by wit h high energy cost due to low CS2 content in the binary azeot ropic mixt ure of CS2 and acetone. If cyclohexane was used as azeot ropic solvent , a great deal of energy could be saved at the sacrifice of reduced purity THF. The separation of an azeot ropic solvent and acetone could be realized through a liquid-liquid extraction process using water as extractive solvent.No waste water and other waste liquid were produced during the whole separation process thanks to the recycling of extractive solvent and azeot ropic solvent. Therefore the separation process developed here could be considered as a clean separation process

Bioaccumulation of nickel from aqueous solutions by genetically engineered Escherichia coli SE5000

[中文文摘]利用基因工程菌E .coliSE5 0 0 0对水体中的镍离子进行富集研究 .菌体细胞对Ni2 + 的富集速率很快 ,富集过程满足Langmuir等温线模型 .经基因改造的基因工程菌不仅最大镍富集容量与原始宿主菌相比增加了 4倍多 ,而且对pH值的变化呈现出更强的适应性 .对离子强度及其它共存重金属离子的影响的实验结果表明 :Na+ ,Ca2 + ,Cd2 + ,Pb2 + 的影响较小 ,但Mg2 + ,Hg2 + ,Cr3 + 和Cu2 + 所引起的负面效应较大 .金属螯合剂EDTA的存在对基因工程菌的富集行为影响很大.[英文文摘]A genetically engineered E. coli SE5000 strain which simultaneously expressed nickel transport system and metallothionine was used to accumulate Ni2 + from aqueous solution. Bioaccumulation process was rapid and followed linearized Langmuir isotherm. A more than fourfolds increase of Ni2 + binding capacity was obtained by genetically engineered E. coli cells compared with original host E. coli cells. A pH assay showed that genetically engineered E. coli cells could accumulate Ni2 + effectively over a broad range of pH (4 to10) and the optimal pH was 816. The presence of 1000mg·L- 1 Na + and Ca2 + , or 50mg·L - 1 Cd2 + or Pb2 + did not have obvious effects on Ni2 + bioaccumulation , while Mg2 + , Hg2 + , Cr3 + and Cu2 + posed severe adverse effects on Ni2 + uptake by genetically engineered E. coli . The presence of EDTA could inhibit nickel uptake.2003年教育部优秀青年教师资助计划; 浙江省自然科学基金 (M203130 )

中国科学院心理研究所会议论文集

5-羟色胺是神经系统内一种非常重要的神经递质,广泛参与各种行为和生理过程。一般认为,5-羟色胺功能低下可导致各种精神疾病,如焦虑、抑郁和创伤后应激障碍等,而这些疾病都伴有负性情绪相关学习记忆的障碍。色氨酸羟化酶(TPH)是5-HT合成过程中一种关键酶,研究显示TPH2基因敲除小鼠其脑内5-HT神经递质匮乏(Liu,Jiangetal.2011)。本研究以THP2基因敲除小鼠为主要研究对象,检测了T&nbsp;</p

Mechanistic Studies on Catalytic Dehydrogenation of Ethylbenzene Over Iron-Oxide-Based Catalyst Systems --Role of Lattice Oxygen

[中文文摘]本文探讨了乙苯催化脱氢制苯乙烯工业氧化铁系催化剂晶格氧与水蒸汽氧的交换以及晶格氧参与反应的微观机理.实验结果表明:催化剂晶格氧参与反应,与水蒸汽氧有交换,反应途径以直接脱氢为主,并发生氧转移脱氢.讨论了两种脱氢反应途径中,晶格氧参与反应的微观过程.强调指出,晶格电子传递和邻近活性位氧化还原周期协同进行是氧转移脱氢机理的必要条件.[英文文摘]The role of lattice oxygen in catalytic dehydrogcnation of ethylbenzene over industrial iron-oxide-based catalysts, 11 (Cr-consaining) and 210 (Cr-free), has been investigated by means of the following experiments: (1) Determination of amounts of H2O produced due to removal of lattice oxygen by reaction with ethyl-benzene used as the feed without addition of steam, and observation of gradual decay of catalytic activities, and changes in the X-ray powder-diffraction patterns of the used catalysts; (2) with ethylbenzene plus D2O as the feed,determination of the change in D2/H2 ratio in the exit gas for very high and very low space velocities;and(3)with ethylbenzene plus D218O as the feed,observation of isotopic exchange of lattice 16O with steam 18O from the red shifts in the IR spectra of the used catalyst.The results indicate that direct heterolytic dehdrogenation of ethylbenzene appcared to be the major rection pathway,but a minor reaction pathway of ethylbenzene dehydiogenation by oxygen-transfer mechanism also appcared to make an apprceiable contribution(about 20%)to the overall conversion.Mechanisms of these two reaction pathways are discussed.For the oxygen-transfer dehydrogenation mechanism,the importance of electron transport between neighboring active-sites operating cooperatively in opposite phascs of their redox cycles is pointed out

基于Malmquist指数法的新疆城市效率评价[J]

利用Malmquist指数法对2006～2011年新疆21个城市的全要素生产率变动情况进行分析,发现新疆城市全要素生产率呈下降趋势,这主要是由于规模效率的下降导致的,且城市效率的变动原因也表现出明显的区域差异.同时,利用DEA模型计算了新疆城市投入要素的非集约度,发现新疆大部分城市投入要素的非集约程度还很高,资源利用和配置效率还很低,在现有技术条件下还有较大的提升空间

三工河流域农户灌溉效率及影响因素[J]

通过三工河流域农户访谈和问卷调查,基于DEA方法,从作物类型和地域空间两方面评价了农户灌溉效率,利用Tobit模型探讨了农户灌溉效率差异产生的影响因素及不同因素对灌溉效率的作用程度。研究结果显示:①不同作物类型的灌溉效率不同,平均灌溉效率的大小依次为棉花(0.95)>葡萄(0.89)>葵花(0.88)>打瓜葫芦(0.80)>玉米(0.78)>小麦(0.72)。②不同地域空间的灌溉效率具有差异,同种作物的平均灌溉效率在兵团与地方间差异显著,兵团略大于地方;上、中、下游进行比较,上游与中下游作物平均灌溉效率差异显著,下游>中游>上游。③灌溉方式、作物类型、收入、灌水量、水价、灌溉管理、技术培训对灌..

中亚增生造山作用及大陆增生[C]

中亚造山带记录了显著的显生宙大陆增生,但是,详细的增生过程仍然是国际学术界争议的前沿课题。在中亚造山带西段新疆北部及邻区,传统的认识为由北往南分为西伯利亚板块、哈萨克斯坦板块和塔里木板块。构造解剖表明夹于中间的哈萨克斯坦板块由不同构造体系组成,不具备统一的基底与组成、统一的古地理区划和大致相同的演化史。其中西准噶尔地区发育发育了多处蛇绿混杂岩,构造变形复杂。详细的野外地质填图、构造解析及年代学分析表明,这些混杂岩实质上包括超镁铁岩、辉长岩、闪长岩、辉绿岩、玄武岩、流纹质火山碎屑岩和硅质沉积物等岩石为不同时代、不同构造背景的岩块,就位时间在308-307 Ma之间。结合区域C3-P1钙碱性、碱性..