15 resultados para C 71, D 63

em Chinese Academy of Sciences Institutional Repositories Grid Portal


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在自然界中存在一套由硅质岩、泥质岩/页岩或板岩、碳酸盐岩和粉砂岩组成的沉积建造,并以富含有机质和菌藻微生物等为特征,沉积厚度较大,岩石类型以硅岩为主,称之为“硅岩建造”。硅岩建造中的硅质岩不仅是许多重要矿种(如金、硒、铀、钒、磷、锰、铂族元素、重晶石和黄铁矿等)的赋存层和含矿岩系的重要岩类,而且由于它形成于特定的地球化学条件下,能够反映出某些沉积相带特殊的地质背景,另外,硅质岩本身就是一种生物岩,对探讨生物成岩、成矿作用有重要意义。所以对硅岩建造及其内硅质岩研究具有十分重要的理论意义和实用价值。因此,本论文选择扬子地块周边寒武系(南秦岭紫阳硒富集区)、二叠系(湖北恩施双河渔塘坝硒矿床)富硒硅岩建造为研究对象。通过岩石地球化学、同位素地球化学、矿物学以及流体包裹体等方法从含硒规律、岩石成因、沉积环境、成矿流体性质等方面,分别对对两个不同时代或不同层位的富硒硅岩建造开展了系统的地球化学对比研究;并从矿物学、包裹体成分及物理化学条件等方面对渔塘坝硒矿床的成因作了探讨。通过研究,取得了以下主要认识:1渔塘坝硒矿区和紫阳硒富集区富硒硅岩建造岩石以硅质岩为主,硅质岩中5102含量范围分别为64.2%-95.84%和63.62%-95.24%。同时包括部分碳质硅质岩丫碳质页岩 和碳、硅板岩及含腐泥层的石煤;渔塘坝硒矿床硅质岩中Se含量大于80ug/g的样品均采自下二叠统茅口组的硅质岩段内,紫阳下寒武统硒富集体中硅质岩中硒的含量最高(可达278ppm)。2微量元素研究表明,两地区富硒硅质岩中均含有较高的Cu,Ni、V、As、Sb、Cr,且U/Th>1。在U-Th、Zr-Cr和P2O5-Y相关图以及Fe-Mn-(Cu+Co+Ni)三角图上,两研究区内硅质岩样品点均落于热水沉积区。渔塘坝硒矿区硅质岩的REE总量较低,平均为38.9×10-6,紫阳硒富集区硅质岩REE总量除个别较高(达110×10-6以上)外,总体也较低(12.0-37.6)×l0-6;另外,从稀土元素配分模式看,两地区硅质岩均有较明显的Ce负异常,且Eu从无明显Eu异常到出现正Eu异常。都反映出热水沉积硅质岩的特征。从si和O同位素组成来看,两个地区硅质岩的δ3051和δ18O值也总体位于热水成因硅质岩区域内。根据隧石一水的氧同位素分馏方程计算得知,两研究区硅质岩的形成温度分别为46℃-72℃和78.6℃-126.20℃。地球化学特征表明,两地区富硒硅质岩均来自热水沉积作用。另外,渔塘坝硒矿区硅质岩中Cr含量较高,且存在腕足类生物化石;紫阳硒富集区硅质岩中Ba及有机质含量较高,且存在叶琳生物标志化合物。结合两地区碳同位素组成特征(渔塘坝地区δ13c为正值,可能和上扬子区早、晚二叠世之间多期次喷发的火山活动,造成地球史上二叠纪生物大灭绝有关;紫阳地区δ13C为负值,说明碳同位素来源于沉积有机物质),暗示两地区硅质岩的成因可能与火山沉积作用有关,且在成岩过程中有部分生物的参与。3渔塘坝赋矿硅质岩硫同位素组成具有较高的负值,表明矿床形成于缺氧的海盆内:紫阳硒富集区形成黄铁矿的硫主要来自海水硫酸盐。4系统研究了渔塘坝硒矿区硒的矿物学,显示硒以自然硒、独立矿物、类质同像及有机吸附四种形式赋存于矿床中。废弃石煤堆中的自然硒矿物,是自然因素和人为活动共同干预的结果,并非石煤的缓慢自燃的结果。5对研究区成矿流体中包裹体均一温度、盐度和密度进行了系统研究,结果显示:两地区的流体包裹体以原生包裹体为主,数量较多且形态复杂;研究区(渔塘坝硒矿和紫阳硒富集区)成矿流体处于中一低温( 190-250)℃和(120-155)℃条件。渔塘坝硒矿区石英和方解石包裹体内的流体盐度分别为(5.9-10.l)B%和(3.9-4.5)WB%,紫阳硒富集区流体盐度为(1.2-2.8)WB%,后者流体盐度明显低于前者。流体密度经计算分别为0.79-0.79/cm3和0.69-0.969/cm3。重点对渔塘坝硒矿区的石英和方解石包裹体进行了拉曼光谱成分测试,结果显示:包裹体成分以H2O和N2为主,含少量 CH4、C2H4、C2H6、C3H5、C4H6、C4H4和C6H6等成分,说明成矿溶液介质主要为具有还原性质的水溶液,其成矿条件具还原性的特点。6渔塘坝硒矿区成矿物理化学条件的研究表明,即富硒成矿流体为中低温(190-250)℃、压力平均为60Mpa。成矿早期02、eZ相对较低,乃较高,且fS2/fSe2>l,有利于硫化物沉淀在成矿主阶段,随着硫化物的沉淀,fS2和fSe2相应增大,且fO2较高。高的fO2阻止了硒进入硫化物,而有利于硒化物的形成。 7系统研究了富硒硅岩建造的沉积环境和构造环境特征,认为渔塘坝硒矿床中富硒硅质岩主要形成于浅海滞留的盆地沉积环境,紫阳下寒武统硅质岩沉积环境属于深水滞留沉积环境;渔塘坝硒矿床主要形成于拉张的断陷盆地中,紫阳硒富集体则形成于拉张的裂谷环境。

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利用夏季自然发情的云南黄牛为受体,开展了奶牛体内冷冻胚胎移植.留用的114头受体牛中,本地黄牛59头,年龄在3~10岁,均为经产牛,最终移植27头,西杂牛56头(其中2岁以下的青年牛26头),移植29头(青年牛11头),两个品种受体利用率分别为45.8%和51.8%;移植后妊娠率分别为59.3%和55.2%;解冻的63枚胚胎移植给了56头受体牛,A级胚胎单独移植和B、C级胚胎搭配移植最终妊娠结果分别是58.5%(24/41)和53.3%(8/15);发情后第6 d和第7 d移植妊娠率分别为56%和58.1%.结果表明,1~10岁的西杂牛和3~10岁体型较大的本地黄牛均可作为受体移植奶牛胚胎;利用自然发情的云南黄牛做受体移植效果较为理想,是一种经济、方便、适合云南广大农村推广的技术途径;A级胚胎单独移植和B、C级搭配移植可获得较为理想的妊娠结果;处于发情后第6 d和第7 d的云南黄牛都可以作为桑囊期奶牛胚胎的移植受体.

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Compensatory growth is a phase of accelerated growth apparent when favourable conditions are restored after a period of growth depression. To investigate if F-2 common 'all-fish' growth hormone gene transgenic common carp (Cyprinus carpio) could mount compensatory growth, a 9 week study at 29 degrees C was performed. The control group was fed to satiation twice a day throughout the experiment. The other two groups were deprived of feed for 1 or 2 weeks, respectively, and then fed to satiation during the re-feeding period. At the end of the experiment, the live masses of fish in the deprived groups were still significantly lower than those of the controls. During the re-feeding period, size-adjusted mean specific growth rates and mean feed intakes were significantly higher in the deprived fish than in the controls, indicating a partial compensatory growth response in these fish. No significant differences were found in food conversion efficiency between the deprived and control fish during re-feeding, suggesting that hyperphagia was the mechanism responsible for increased growth rates. The proximate composition of the deprived fish at the end of the experiment was similar to that of the control fish. This study is, to our knowledge, the first to report that fast-growing transgenic fish can achieve partial compensation of growth following starvation. (c) 2007 The Authors Journal compilation (c) 2007 The Fisheries Society of the British Isles.

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本工作以EV共聚物为研究对象,明确地提出了共聚物的序列结构与其~(13)C NMR谱,包括符号表示在内的一致性问题。通过对EVAc共聚物~(13)C NMR谱的分析认为,共聚物的序列结构与其~(13)C NMR谱之间存在着某种内在的联系。我们从EV共聚物序列结构的符号表示和Bovey关系出发,阐述了它们之间的一致性,即一一对应关系,并发现了EV共聚物~(13)C NMR谱的两种类型,提出了利用取代基参数进行EV共聚物~(13)C NMR谱分类的判别标准及其衍生出的两种判别方法,阐述了关于EV共聚物~(13)C NMR谱峰分布的预见性。

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利用江都市小记镇的稻-麦轮作FACE平台,在水稻生长季研究了不同施肥(施常规氮量和低氮量)、不同秸秆还田(秸秆全还田、秸秆半还田、秸秆不还田)处理土壤中的硝化、反硝化、产甲烷和甲烷氧化菌数量变化,借助气相色谱测定了土壤的反硝化潜力、产甲烷潜力和甲烷氧化潜力。并对水稻土中的硝酸还原酶、脲酶、蔗糖酶和过氧化氢酶活性及有效C、N含量也进行了研究,目的是评估FACE稻田土壤反硝化活性和甲烷产生能力。 结果表明:与对照相比,FACE稻田土中的有效N含量呈降低趋势;土壤反硝化潜势明显受到抑制;水稻生长各时期土壤反硝化菌群数量也趋于减少,这种现象在常规氮肥施用及秸秆不还田情形下表现最为显著(P<0.01);在水稻的大多数生育期土壤中的硝酸还原酶和脲酶活性也受到抑制;总体表现为FACE稻田土壤反硝化活性受到抑制。FACE既促进土壤的甲烷产生潜力,也促进甲烷氧化能力;对产甲烷菌在分蘖期具有促进作用,而在抽穗与收获期具有抑制作用,这种作用在低氮条件下达到显著水平(P<0.05)。同样,在低氮条件下,FACE促进了水稻生长前3个时期土壤甲烷氧化菌群数量增长,仅在收获期表现为抑制作用,因而,FACE稻田甲烷产生是产甲烷和氧化综合作用的结果。

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工业革命以来,由于人口的快速增加和人类活动的强烈干扰(主要包括煤炭、石油等石化燃料的燃烧、化肥生产和使用)导致土地利用/覆被变化、大气CO2浓度升高、N沉降等一系列全球环境变化问题。有关陆地生态系统生物地球化学循环,尤其是陆地生态系统C、N循环及其耦合过程方面的研究成为全球变化科学研究领域的重要内容。 干旱/半干旱地区占地球陆地总面积的1/3。与湿润地区相比较,干旱/半干旱地区生态系统稳定性比较差,往往属于生态脆弱区。因此,全球变化对干旱/半干旱地区生态系统影响更加敏感。科尔沁沙地位于我国北方干旱/半干旱地区,是我国典型的农牧交错区和生态脆弱区。科尔沁沙地是世界上人口密度最高的干旱/半干旱地区之一,人类活动对其影响剧烈。然而,有关科尔沁沙地生态系统C、N元素生物地球化学循环过程对土地利用/覆被变化、N沉降等全球变化响应及其反馈机制的研究非常缺乏。因此,本文以科尔沁沙地退化沙质草地、农田、不同年龄樟子松和杨树人工林等生态系统为对象,开展了造林、模拟N沉降和凋落物管理对生态系统C、N元素循环过程影响的研究。 在科尔沁沙地东南缘,以退化沙质草地、樟子松(Pinus sylvestris var. mongolica)人工林(15、24和30年生)、杨树(Poplus xiaozhuanica)人工林(7、11和15年生)为对象,研究草地转变为林地对生态系统C、N储量影响;以退化草地、榆树疏林草地和32年生樟子松人工林为对象,比较草地造林对土壤C、N循环过程及其土壤微生物性状的影响;以农田和5、10、15年生杨树人工林为对象,研究退耕还林对生态系统C、N储量和循环过程影响;以35年生樟子松人工林为对象,模拟研究N沉降和凋落物管理对生态系统C、N循环过程影响。通过上述研究,得到以下主要结果: (1)草地生态系统总C储量为34.38 Mg ha-1,15、24和30年生樟子松人工林生态系统总C储量分别为43.56、60.45和66.59 Mg ha-1,7、11和15年生杨树人工林生态系统总C储量分别为34.54、48.26和78.77 Mg ha-1;与农田相比,退耕5年的杨树人工林生态系统总C库储量下降13%,而10年和15年杨树人工林分别增加了176%和5倍;随着人工林年龄的增加,地上植被生物量C库储量占生态系统总C库储量的比例逐渐增加,并主要分配在树干。草地生态系统总N库储量为2.54 Mg ha-1,15、24和30年生樟子松人工林生态系统总N库储量分别为1.96、2.10和2.19 Mg ha-1,7、11和15年生杨树人工林生态系统总N库储量分别为2.27、1.84和2.60 Mg ha-1;与农田相比,退耕5年的杨树人工林生态系统总N库储量下降32%,而10年和15年杨树人工林分别增加了47%和76%;农田和草地造林后生态系统N储量依然主要分配在土壤中。 (2)草地和农田造林后土壤C、N库储量的变化受多因子的影响,例如林龄、树种种类以及立地条件等。农田和草地造林初期,土壤C、N库储量表现出下降趋势,随着林龄的增加,土壤C、N储量逐渐恢复。草地营造樟子松人工林30年后,0–60 cm深度土壤C、N储量依然显著低于草地;与草地相比,15年生杨树人工林土壤C、N储量差异不显著。在立地条件较好的情况下,10年杨树人工林土壤C、N储量已显著高于农田;然而,在立地条件相对较差的情况下,15年杨树人工林土壤C、N储量仍然与农田相比差异不显著。 (3)土地利用变化能够强烈地改变土壤C、N循环过程。与草地或疏林草地相比,32年生樟子松人工林土壤C、N、P含量显著降低;土壤C、N矿化过程发生显著变化,并且受季节变化的影响;在不同季节,土壤微生物量碳含量、代谢熵(qCO2)、微生物熵(MBC/TOC)以及土壤酶活性等在不同土地利用条件下表现出规律不一致。同样,农田退耕杨树人工林能够显著影响土壤C、N矿化过程,土壤无机氮(铵态氮+硝态氮)含量,土壤微生物量碳含量以及土壤微生物活性。草地造林在一定程度上导致土壤质量下降。而农田造林有利于土壤质量改善,尤其在在立地条件较好情况下。 (4)N添加增加对沙地樟子松人工林地上和地下C、N元素含量影响不大;N添加1年后,仅林下植被C、N含量显著增加,高氮处理(N15)凋落物N含量显著增加。N添加抑制了沙地樟子松人工林凋落物的早期分解和N、P元素释放。5、6、8和9月份土壤无机N含量均随着N输入增加表现出一定程度的增加,然而,7月份N添加导致土壤无机N含量降低。N添加对土壤潜在N矿化速率影响不显著。7和8月份N添加影响土壤C矿化速率,而其它月份影响不显著。低氮处理(N5)有利于增加土壤微生物量碳含量,而高氮处理(N15)在一定程度上降低土壤微生物量碳含量。 (5)凋落物输入变化(凋落物添加和凋落物移出)在一定程度上改变了35年生沙地樟子松人工林生态系统C、N循环过程。凋落物移出(C0)增加了林下植被C含量,降低了树木叶片N含量。凋落物移出抑制了凋落物分解和P元素的释放,而增加了C元素的早期释放速率,对N元素释放过程影响不显著。凋落物输入变化对不同月份土壤无机N含量和土壤N矿化过程影响均不显著。仅在6月份凋落物移出显著抑制了土壤C矿化速率,其它月份差异均不显著。凋落物管理对土壤微生物量碳含量影响不显著。 以上研究结果表明,土地利用变化、N沉降和凋落物输入改变等能够影响半干旱地区沙地生态系统C、N储量和循环过程。尤其是土地利用变化强烈改变沙地生态系统C、N储量、分配格局和循环过程,并且受到多因子的影响。科尔沁沙地樟子松人工林生态系统C、N元素生物地球化学循环存在密切的耦合关系。今后有必要进一步结合3S技术、同位素技术、模型模拟以及分子生物学技术等,从微观-宏观不同尺度上,研究半干旱地区沙地生态系统C、N循环过程对全球变化的响应及其反馈机制。

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本文研究了维生素C生产菌系2980的生长和产酸代谢规律,主要环境因子的影响及生产调控。研究结果表明:2980混合菌系在种子罐和300M3发酵罐混合培养时,呈现一种协同共生的关系。在流加糖发酵过程中,2-酮基-L-古龙酸的合成有两个高峰期:8-20小时和24-40小时高峰期。L-山梨糖脱氢酶总酶活迅速上升,2-酮基-L-古龙酸还原酶活性始终呈平缓上升趋势。环境因子对棍菌间的协同共生影响其显著。在种子罐培养中,采取适宜的接种量、通气量、p日、温度和营养,可获较佳的菌群状态。在发酵罐内,生长期不同,对’环境的温度、通气量、介质和p日值要求不同。对数生长期和稳定生长期,提高温度、p日值、通气量、接种量和采用较低的初始糖浓以及添加FeCl3,有利于菌系生长和产酸代谢。新的调控工艺,种液可较快调整到最佳接种状态且衰亡较慢,发酵罐内佩狗菌系结构和菌群状态得到改善。发酵平均转化率为89.51%,较之对照提高4.21%,平均周期为51.2小时,较之对照缩短4.8小时。

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以氧化葡萄糖酸杆菌和巨大芽孢杆菌混合培养物的无细胞抽提液建立了Vc二步发酵离体实验系统.反应体系中加入山梨糖在pH7.0,35℃下保温24h,2-酮基-L-古龙酸(2KGA)生成.巨大芽孢杆菌胞外活性物质对离体系统的产酸没有影响,一定量的L-山梨糖脱氢酶可促进产酸.从氧化葡萄糖酸杆菌细胞质中分离纯化出L-山梨糖脱氢酶.L-山梨糖脱氢酶酶活与2KGA的形成呈正相关:L-山梨糖的转化是在细胞内进行的;亲缘关系相差甚远的伴生菌均能促进小菌产酸,且“伴生”效率相近;伴生菌通过促进产酸菌生长和提高其L-山梨糖脱氢酶比活力而提高发酵系统中L-山梨糖脱氢酶总活力,并且通过促进产酸菌合成新的RNA而增强其代谢力,从而促进产酸;通过对不同发酵时间L-山梨糖脱氢酶酶活及2KGA累积量的比较表明,此酶可作为生产上2KGA生成的实时监控的指示酶;环境因子通过提高酶活力促进产酸.

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本学位论文共有5章。第一章报道白芍的化学成分及芍药苷的微生物转化研究成果;第二章报道天山雪莲的化学成分研究;第三章报道两面针的化学成分研究;第四章报道通关藤的化学成分研究成果;第五章概述了花椒属植物中最近十年报道的新化合物及药理研究情况。 在第1章的第一部分报道了白芍(Paeonia lactiflora Pall.)的化学成分。我们采用正、反相硅胶柱层析等各种分离方法,从白芍的干燥根中共分离出14个化合物,其中1个为新化合物,其结构通过波谱分析证实为没食子酰白芍苷,另外还有2个为首次从该植物中分离得到。第二部分报道了芍药苷的微生物转化生产芍药苷代谢素-I的研究,从15株厌氧菌中筛选出10株有转化活性的菌株,其中短乳杆菌Lactobacillus brevis AS1.12的转化活性最好,对其转化条件进行了初步的筛选,确定了相对合理的转化工艺。 在第2章报道了天山雪莲(Saussurea involucrate Kar.et Kir.)全草乙醇提取物化学成分的分离纯化和结构鉴定。通过正、反相硅胶柱层析等分离纯化和MS、NMR等波谱解析,共分离鉴定了28个化合物,结构类型分属于黄酮、倍半萜和木脂素等,其中2个新倍半萜化合物的结构分别表征为6α-羟基云木香酸6-β-D-吡喃葡萄糖苷和11βH-11,13-二氢去氢云木香内酯8α-O-(6′-乙酰)-β-D-吡喃葡萄糖苷。 第3章报道了两面针(Zanthoxylum nitidum (Roxb.)DC.)干燥根的乙醇提取物化学成分的分离纯化和结构鉴定。通过正、反相硅胶柱层析等分离纯化和MS、NMR等波谱解析以及X-射线单晶衍射,共分离鉴定了16个生物碱,结构类型分属于苯并啡啶类、喹啉类和阿朴啡类等,其中2个新苯并啡啶类生物碱的结构分别表征为二聚双氢两面针碱和丙酮基双氢崖定椒碱。 第4章报道了通关藤(Marsdenia tenacissima (Roxb.) Wight et Arn.)水提取物化学成分的分离纯化和结构鉴定。通过正、反相硅胶柱层析等分离纯化和MS、NMR等波谱解析以及X-射线单晶衍射,共分离鉴定了14个化合物,结构类型均属于C21多羟基甾醇,其中4个新化合物tenacigenoside A, tenacigenoside B, tenacigenoside C和tenacigenoside D的结构分别表征为3-O-6-deoxy-3-O-methyl-β-D-allopyranosyl-(1→4)-β-D-oleandropyranosyl-17β-tenacigenin B (62), 3-O-2,6- dideoxy-4-O-methyl-D-lyxo-hexopyranosly-11α-O- methylbutyryl-12β-O-acetyl-tenacigenin B (63), 3-O-6-deoxy-3-O-methyl-β-D- allopyranosyl-(1→4)-β-D-oleandropyranosyl-11α-O-tigloyl-tenacigenin C (64)和3-O-6-deoxy-3-O-methyl-β-D-allopyranosyl-(1→4)-β-D-oleandropyranosyl-11α-O-2- methylbutyryl-tenacigenin C (65)。 第5章概述了花椒属植物的化学成分及药理活性研究进展。 This dissertation consists of 5 chapters. The first chapter elaborate the phytochemical investigation of Paeonia lactiflora Pall., and microbial transformation of paeoniforin. The second, third and four chapters elaborate the phytochemical investigation of Saussurea involucrate Kar.et Kir., Zanthoxylum nitidum (Roxb.) DC. and Marsdenia tenacissima (Roxb.) Wight et Arn., respectively. Chapter 5 is a review on chemical constituents and bioactivities of Zanthoxylum species. The part one of chapter 1 focus on the isolation and identification of chemical constituents from P. lactiflora. Fourteen compounds were isolated from the roots of P. lactiflora by repeat column chromatography over normal and reversed phase silica gel. Among them, one is a new compound and the structure was suggested as galloyl-albiflorin by spectral evidence. In addition, two compounds were firstly reported in this plant. The part 2 is about microbial transformation of paeoniforin. Chapters 2, 3 and 4 were isolations and identifications of chemical constituents from S. involucrate, Z. nitidum and M. tenacissima, respectively. From the aerial parts of S. involucrate, 28 compounds including 7 flavonoids and 13 sesquiterpenoids were isolated and identified. Among them, 2 new compounds were characterized as 6α-hydroxycostic acid 6-β-D-glucoside and 11βH-11,13-dihydrodehydro- costuslactone 8α-O-(6'-acetyl)-β-D-glucoside, respectively, by means of spectroscopic analysis. Otherwise, 11 ones were firstly reported from this plant. The third chapter is about the phytochemical investigation of Z. nitidum. Sixteen compounds were isolated and identified. Among them, 2 new benzophenanthridine alkaloids were characterized as 8-acetonyldihydrofagaridine and 1,3-bis(8-dihydronitidinyl)-acetone by spectroscopic analysis. The fourth chapter is about the phytochemical investigation of M. tenacissima. Fourteen compounds were isolated and identified. Among them, 4 new compounds, tenacigenosides A~D, were characterized as 3-O-6-deoxy-3-O-methyl-β-D-allopyranosyl-(1→4)-β-D-oleandropyranosyl-17β- tenacigenin B, 3-O-2,6-dideoxy-4-O-methyl-D-lyxo-hexopyranosly-11α-O-methyl butyryl-12β-O-acetyl-tenacigenin B, 3-O-6-deoxy-3-O-methyl-β-D-allopyranosyl- (1→4)-β-D-oleandropyranosyl-11α-O-tigloyl-tenacigenin C, and 3-O-6-deoxy-3-O- methyl-β-D-allopyranosyl-(1→4)-β-D-oleandropyranosyl-11α-O-2-methylbutyryl- tenacigenin C. Chapter 5 is a review on recent progress in bioactive constituents from plants of Zanthoxylum species.

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从新几内亚核桃木的树皮中分离得到的吲哚类喹诺里西定生物碱10-Desbromoarborescidine A,因发现其具有阻滞钙离子通道的活性而倍受关注。10-Desbromoarborescidine A由A、B、CD四个环组成,只有一个手性中心,是吲哚生物碱中结构较简单的一种,常作为此类生物碱全合成方法的模型化合物。但迄今为止,能高效而简便的实现手性10-Desbromoarborescidine A不对称全合成方法线路不多,大多数以不对称诱导的方式建立其手性中心,手性催化的方式仅有一例金属催化。从逆合成分析可知,Desbromoarborescidine A的全合成可以通过亚胺不对称催化还原进行关键的手性中心构建,而本课题组在之前的研究中通过手性有机小分子催化剂的发展,已将三氯硅烷氢转移还原亚胺发展成了一类简便实用、高效、高对映选择性并具有优良底物适应范围的不对称催化反应,我们希望以这一反应作为关键手段,发展一条Desbromoarborescidine A及其类似物不对称合成新路线。 根据我们设计的新路线,首先成功合成了其关键中间体,然后我们进行了关键的不对称催化尝试。用本实验室已有的高性能有机小分子催化剂虽得到了较好的对应选择性,但是产率很低。同时,为了验证整条线路的可行性,我们也用消旋的中间体进行拉通线路的尝试。但不幸的是,在脱除保护基时遇到了很大困难。尝试换不同的保护基,或改变脱保护基的顺序,都未能成功合成目标产物。究其原因可能是由于吲哚的特殊性造成的,吲哚类亚胺与常规的芳香亚胺有较大的差异,其NH基团无论保护还是不保护,对与其2位相联接的C=N双键均有很大的影响,导致其不对称催化还原难以进行。另外,由于所设计的还原产物含有处在吲哚苄位的胺基,稳定性较差,造成保护基脱除困难。 烯胺C-亚磺酰化反应是本课题组最近发现的一个新反应,之前未见文献报道。本研究对该反应进行了反应条件优化和底物扩展,发现带Cbz,AcCOt-Bu,CO2Et,Bz等保护基的一系列环状和非环状烯胺在亚磺酸钠、DMAc和MeSiCl3的共同作用下能高效高产率生成β-胺基烯基亚砜类新化合物,为合成多官能团化的烯基亚砜新化合物提供了一条简便实用的途径。 The main constituent of Dracontomelum mangiferum B1, indoloquinolizidine alkaloid 10-Desbromoarborescidine A, has drawn great attention due to its calcium channel blocking activity. Its molecular structure is relatively simple compared with the other alkaloids of the same type, which has only one chiral center, albeit with four cycles A, B, C, and D. This compound is often used as a model target for exploring different strategies for the total synthesis of indole alkaloids. Nevertheless, so far there still lack practical and highly efficient methods for the asymmetric total synthesis of 10-Desbromoarborescidine A. Most of the current available methods rely on stoichiometric asymmetric synthesis for the construction of the chiral center. There is only one example reporting utilization of asymmetric catalysis, but with transition metal complex as the catalyst. Our retrosynthetic analysis shows that catalytic asymmetric reduction of imine could be used as the key step for the construction of the chiral center of Desbromoarborescidine A. Since in the previous studies our group has developed the asymmetric reduction of imines by trichlorosilane into a practical and highly efficient and enantioselective method using newly designed chiral organocatalysts, we hope to apply this method to develop a novel synthetic route for the total synthesis of Desbromoarborescidine A and its analogues in this study. According to the newly designed synthetic route, we first accomplished the synthesis of the key intermediates which was then examined for the critical asymmetric catalysis. The asymmetric reduction using the highly efficient organocatalysts, developed in our lab afforded high ee but poor yield. We tried different reaction conditions to improve the yield, but failed to get any good results. Simultaneously, to vertify the feasibility of the synthetic route we designed, we also tired to go through the route toward the racemic synthesis of Desbromoarborescidine A. But unfortunately, protection and deprotection proved to be big hurdles. All the different protection groups and different sequences of protection and deprotection we tried failed to get us through the designed synthetic sequence and furnish the final product. Most likely, the indole part is the culprit behind the failures.The NH group of the indole, no matter protected or not, may impact the catalytic asymmetric reduction of C-N double bond connected with 2-C. Additionally, the reduction product we designed contains an amino group in the β-position of the indole, which may cause problems due to its instability. C-sulfenylation of enamines is a novel reaction discovered recently by our group, which has not been seen before in the literature. In this study, optimization of the reaction conditions and exploration of the substrate scope were further undertaken for this reaction, which reveal that a series of enamines with N-Cbz, Ac, COt-Bu, CO2Et protection groups could all undergo smooth C-sulfinylations with the comined use of sodium benzene sulphinate, DAMc and MeSiCl3, efficiently furnishing the β-amino vinylsulfoxide products in high yield, affording a practical and highly efficient methods for synthesis of functional vinylsulfoxides.

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Yields, correlation shapes, and mean transverse momenta p(T) of charged particles associated with intermediate-to high-p(T) trigger particles (2.5 < p(T) < 10 GeV/c) in d + Au and Au + Au collisions at root s(NN) = 200 GeV are presented. For associated particles at higher p(T) greater than or similar to 2.5 GeV/c, narrow correlation peaks are seen in d + Au and Au + Au, indicating that the main production mechanism is jet fragmentation. At lower associated particle pT < 2 GeV/c, a large enhancement of the near- (Delta phi similar to 0) and away-side (Delta phi similar to pi) associated yields is found, together with a strong broadening of the away-side azimuthal distributions in Au + Au collisions compared to d + Au measurements, suggesting that other particle production mechanisms play a role. This is further supported by the observed significant softening of the away-side associated particle yield distribution at Delta phi similar to pi in central Au + Au collisions.

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中国西南喀斯特地区有突出的地球化学敏感性和生态环境脆弱性等特征,其中水环境污染是喀斯特地区所面临的极其严重的生态与环境问题。水环境生源物质循环过程对于人类生存环境质量的保护和提高有着直接的联系,由于环境体系受多种控制因素影响,利用多同位素方法讨论单一环境体系中物质循环过程和生态环境效应已成为同位素地球化学发展的一个重要趋势。碳、氮同位素已被广泛用于探讨和解决当前的一些重大环境问题,如生源要素生物地球化学对人为污染物的响应、温室气体的来源、湖泊富营养化、地下水硝酸盐污染等。为此本论文利用稳定同位素技术(13C、I5N、18O),以喀斯特城市地下水为主要研究对象,对贵阳雨水中的C、N沉降过程、贵阳/遵义地下水C、N同位素地球化学进行了初步研究。通过以上研究,得到以下的主要认识。1.探讨了贵阳雨水中碳沉降的年变化特征,结果表明贵阳雨水DOC平均值为3.76mg/L,POc平均值为0.54mg/L,含量季节间变化不显著。雨水中DOc与PH呈负相关关系,表明有机碳中酸性成份对酸雨有一定贡献。δ13C-POC取值范围在(-27.0,-24.0‰)之间,季节间差异不大,结合已有研究结果表明雨水中颗粒有机碳主要来源于雨水所冲刷的本地大气颗粒物。2.探讨了贵阳雨水无机氮沉降的年变化特征,结果表明贵阳城区雨水中的NH4+、NO3-、δ15N-NH4+,δ15N-NO3-,δ18O-NO3-,季节性差别都不大。NH4+主要来源于土壤中NH3挥发以及大气颗粒物中按的洗脱,而硝酸盐可能主要来源于燃煤和机动车的排放等,同时气候是影响同位素组成差异性表现的一个重要影响因素。3.初步分析了贵阳与遵义地下水/地表水主要水化学成分,结果证实水体水化学组成主要受研究区水文地质背景控制,即阳离子主要以Ca2+,Mg2+为主,而阴离子以HCO3-,SO42-离子为主。但是有部分水样有较高的人为输入物质K+,Na+,Cl-和NO3-,表明人为活动在研究区内已对地表水/地下水产生一定影响。4.利用碳同位素较好地示踪了地下水溶解无机碳季节变化的主要规律,地下水夏季的DIC含量明显低于冬季DIC含量,这是由于大量降水的稀释作用引起的。地下水DIC夏季一般比冬季更富集12C,表明夏季地下水中生物成因无机碳贡献增加。经计算表明贵阳/遵义地下水来源于碳酸盐风化的无机碳比重大多数大于50%,表明硫酸可能参与风化过程。5.较为系统地探讨了地下水/地表水中有机碳的冬季/夏季演化规律以及受影响因素,地下水大多数样品DOC和POC含量不高,个别受污染样品明显具有较高有机碳含量。大部分夏季地下水δ13C-POC明显大于冬季,表明夏季地下水颗粒有机碳受外源(C4植物碎屑)输入影响。地表水TOCDOC+POC)与人为输入离子[K+Na++Cl-]呈一定的正相关关系,表明有机碳主要受人为污染影响。6.以贵阳为例,根据δ13CDIC等势图、结合主要水化学特征在空间上的分布可知,贵阳市区中部,东北部及西郊农业区地下水受污染较为严重。表明一定条件下,碳同位素组成可以用来指示区域地下水受人为活动影响范围。7.通过对地下水三氮分析初步掌握了地下水氮污染的基本特征,地下水中NO3-是最主要的无机氮形态,NH4+和NO2-含量大多较低,地下水中具有高NO2-与NH4+的水样比较分散,表明点源污染是主要的。8.利用氮氧同位素示踪了贵阳地下水硝酸盐污染来源的季节变化,同时证实了部分地下水发生反硝化。冬季硝酸盐相对夏季含量较低,并且目SN与夕80的平均值都相对较高,表明夏季受外源氮污染明显,郊区地下水硝酸盐主要受硝态氮肥污染影响,城区地下水硝酸盐污染严重,城市生活排泄物是主要的氮污染源;硝酸盐氮氧同位素联同按氮同位素等可以得知部分地下水中存在明显的反硝化作用。9.利用氮同位素取值分布和季节间频度分布变化初步讨论了遵义地下水硝酸盐污染来源的季节变化。遵义含NO3-较高的地下水主要分布在市区、茅草铺(市东北郊)和新店子一忠庄一带(市东南郊)。夏季地下水硝酸盐δ15N的平均值明显低于冬季,一表明夏季地下水受农业化肥等低δ15N值氮污染源污染。10.两城区地下水受点源污染为主,在局部区域有向含水层面源污染转化的趋势。喀斯特城区地下水中C、N物质的循环对环境变化响应较快,同时受不同区域降雨过程和土壤营养物质过程影响而表现出一定的差异性。

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锑成矿中有机作用的研究国内外进行得极少,本文首先运用(有机)包裹体探讨了大厂锑成矿流体的一系列物理化学性质和主要成矿特征:1.成矿温度与盐度分别为150-180℃ 和10-12 Wt%,2.主成矿阶段水质类型属 F-SO_4Ca-K型,气相成份中甲烷含量较高(C_1/C_2~C_4 > 1),3. 成矿介质水主要来自大气降水,δD=-63~-66‰, δ~(18)O = -3.5~-0.6‰)。有机地球化学研究显示岭好组有机碳含量高(平均 Corg = 0.71% > 0.5%),完全具备生油能力,是一重要的烃源层。有机质反射率(Ro)达1.87-2.93%,演化程序较高,热变沥青多呈充填状,具明显的运移特征。模拟实验证明石油对锑有较强的萃取能力,可作为 Sb 迁移的良好载体;且按萃取实验结果,有机迁移与无机迁移同等重要。对腐殖酸(质)和高硫原油作了较详细的讨论--腐殖酸(质)在形成矿源层中有重要作用,高硫原油热裂解本身可以产生H_2S,提供部份硫;而辉锑矿的最终形成则缘于大气降水的加入,温度降低和氧化等因素综合作用的结构。总结不同阶段不同有机质的不同作用,提出了有机-无机综合成矿模式。

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To explore the neural mechanisms underlying conditioned immunomodulation, this study employed the classical taste aversion (CTA) behavioral paradigm to establish the conditioned humoral and cellular immunosuppression (CIS) in Wistar rats, by paring saccharin (CS) with intraperitoneal (i.p.) injection of an immunosuppressive drug cyclophophamide (UCS). C-fos immunohistochemistry method was used to observe the changes of the neuronal activities in the rat brain during the acquisition, expression and extinction of the conditioned immunosuppression (CIS). The followings are the main results: 1. Five days after one trial of CS-UCS paring, reexposure to CS alone significantly decreased the level of the anti-ovalbumin (OVA) IgG in the peripheral serum. Two trials of CS-UCS paring and three reexposures to CS not only resulted in further suppression of the primary immune response, but also reduced the numbers of peripheral lymphocytes and white blood cells. This finding indicates that CS can induce suppression of the immune function, and the magnitude of the effects is dependent on the intensity of training. 2. On day 5 following two trials of CS-UCS pairing, CS suppressed the spleen lymphocytes responsiveness to mitogens ConA, PHA and PWM, and decreased the numbers of peripheral lymphocytes and white blood cells. On day 15, only PHA induced lymphocyte proliferation was suppressed by CS. On day 30, presentation of CS did not have any effect on these immune parameters. These results suggest that the conditioned suppression of the cellular immune function can retain 5-15 days, and extinct after 30 days. 3. CTA was easily induced by one or two CS-UCS parings, and remained robust even after 30 days. These data demonstrate that CIS can be dissociated from CTA, and they may be mediated by different neural mechanisms. 4. Immunohistochemistry assays revealed a broad pattern of c-fos expression throughout the rat brain following the CS-UCS pairing and reexposure to CS, suggesting that many brain regions are involved in CIS. Some brain areas including the solitary tract nucleus (Sol), lateral parabrachial nucleus (LPB) and insular cortex (IC), showed high level c-fos expressions in response to both CS and UCS, suggesting that they may be involved in the transmission and integration of the CS and UCS signals in the brain. There were dense c-FOS positive neurons in the paraverntricular nucleus (PVN) and supraoptic nucleus (SO) of hypothalamus, subfornical organ (SFO) and area postrema (AP) etc. after two trials of CS-UCS paring and after the reexposure to CS 5 days later, but not in the first training and after the extinction of CIS (30 days later). The results reflect that these nuclei may have an important role in CIS expression, and may also response to the immunosuppression of UCS. The conditioned training and reexposure to CS 5 days later induced high level c-fos expression in the cingulate cortex (Cg), central amygdaloid nucleus (Ce), intermediate part of lateral septal nucleus (LSI) and ventrolateral parabrachial nucleus (VLPB) etc. But c-fos induction was not apparent when presenting CS 30 days later. These brain regions are mainly involved in CIS, and may be critical structures in the acquisition and expression of CIS. Some brain regions, including the frontal cortex (Fr), ventral orbital cortex (VO), IC, perirhinal cortex (PRh), LPB and the medial part of solitary nucleus (SolM), showed robust c-FOS expression following the conditioning training and reexposure to CS both on day 5 and day 30, suggesting that they are critically involved in CTA.