42 resultados para Ovidio Nasón, Publio, 43 a.C.-17 d.C.

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本论文对四川蜡瓣花 (Corylopsis willmottiae Rehd. et Wils.)、密花樫木[Dysoxylum densiflorum (Blume) Miq.]、四川溲疏 (Deutzia setchuenensis Franch)及云南豆腐柴 (Premna yunnanensis W. W. Smith)的化学成分进行了研究。通过色谱分离得到44个化合物。主要基于波谱数据鉴定了它们的结构,其中1个为新化合物。 1.从四川蜡瓣花全株的95%乙醇提取物中共分离鉴定了13个化合物,它们是:1-O-(3-O-甲基没食子酸)-岩白菜素(1)、11-O-没食子酰基岩白菜素(2)、 11-O-紫丁香基岩白菜素(3) 、岩白菜素(4)、4-O-没食子酰基岩白菜素(5) 、4,11-O-二没食子酰基岩白菜素 (6)[14]、β-谷甾醇 (7)、acetyl aleuritolic acid (8)、(-)-表没食子儿茶素没食子酸酯(9)、对羟基苯甲酮 (10)、 11-香豆酸酰岩白菜素 (11)[19]、丁香酸 (12)和没食子酸 (13)。其中1为新化合物。 2.从密花樫木根的95%乙醇提取物中共分离纯化了13个化合物,它们是:β-白檀酮(14)、richenone (15)、β-谷甾醇 (7)、cabraleadiol (16)、β-香树脂醇 (17)、龙脑香醇酮 (18)、cabraleadiol monoacetate (19)、cabraleone (20)、3β-hydroxy-5 -pregnen-20-one (21)、3β-hydroxy-5α-pregnan-20-one (22)、cabraleahydroxylactone (23)、川楝子甾醇B (24)、表儿茶素 (25)。 3.从四川溲疏全株95%乙醇提取物中共分离11个化合物,鉴定了其中的9个化合物。它们是:β-谷甾醇 (7)、白桦酯醇(26)、齐墩果酸(27)、hydrangetin (28)、肉桂酸 (29),齐墩果酸-3-O-β-D-吡喃葡萄糖醛酸苷(30)、β-胡萝卜苷 (31)、齐墩果酸-3-O-(β-D-吡喃葡萄糖醛酸-6-正丁酯)(32)、齐墩果酸-3-O-β-D-吡喃葡萄糖醛酸-28-O-β-D-吡喃葡萄糖苷 (33)。 4.从云南豆腐柴95%乙醇提取物中分离得到12个化合物,分别为白桦脂醇 (25)、7-羟基黄烷酮 (34)、松属素 (35)、2’,4’-羟基查儿酮 (36)、高良姜素-3-甲醚 (37) 、高良姜素-3,7-二甲醚 (38)、异甘草素-4-甲醚 (39)、豆蔻明 (40)、乔松酮 (41)、异甘草素 (42)、arjunolic acid (43)、槲皮素3-O-β-D-木糖苷(44)。 5.综述了1976年以来樫木属植物化学成分和活性研究的概况。 Phytochemical investigation on Corylopsis willmottiae, Dysoxylum densiflorum, Deutzia setchuenensis, and Premna yunnanensis, led to the isolation of 44 compounds, 1 of which was new one. 1. One new compound was isolated from 95% ehanolic extrat of the whole plants of C. willmottiae, identified as 11-O-(3-O-methylgalloyl)-bergenin (1). The twelve known compounds isolated were 11-O-galloylbergenin (2), 11-O-syringylbergenin (3), bergenin (4), 4-O-galloylbergenin (5), 4,11-di-O-galloylbergenin (6), β-sitosterol (7), acetyl aleuritolic acid (8), (-)-epigallocatechin 3-O-gallate (9), 1-(4-hydroxyphenyl) ethanone (10), 11-O-coumaroylbergenin (11), syringic acid (12), gallic acid (13). 2. Thirteen compounds were isolated from 95% ethanol extract from the roots of D. densiflorum and identified as β-amyrenone (14), richenone (15), β-sitosterol (7), cabraleadiol (16), β-amyrin (17), hydroxydammarenone-Ⅱ (18), cabraleadiol monoacetate (19), cabraleone (20), 3β-hydroxy-5-pregnen-20-one (21), 3β-hydroxy-5α-pregnan-20-one (22), cabraleahydroxylactone (23), toosendansterol B (24) and (-)-epicatechin (25). 3. Eleven compounds were isolated from ethanol extract of D. Setchuenensis. Nine were identified as β-sitosterol (7), betulin (26), oleanolic acid (27), hydrangetin (28), cinnamic acid (29), oleanolic acid 3-O-β-D-glucuronopyranoside (30), β-daucosterol (31), oleanolic acid 3-O-β-D-glucuronopyranoside-6-O-butyl ester)(32), oleanolic acid 3-O-β-D-glucuronopyranosyl-28-3-O-β-D-glucopyranoside (33). 4. Twelve compounds were isolated from ethanol extract of P. yunnanensis and identified as betulin (26), 7-hydroxyflavanone (34), pinocembrin (35), 2’,4’-dihydroxychalcone (36), galangin 3-methyl ether (37), galangin 3,7-dimethyl ether (38), isoliquiritigenin 4-methyl ether (39), cardamonin (40), pinostrobin (41), isoliquiritigenin (42), arjunolic acid (43), quercetin 3-O-β-D-lyxosopyranoside (44). 5. Chemical constituents and biological activities of the genus Dysoxylum (Meliaceae) were reviewed during 1976-2009.

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Metallocene based polyethylenes were prepared by SMOPEC's "metallocene adduct" technology in a gas phase fluidized bed model reactor. The C-13-NMR spectra of ethylene/1-butene (S-34) and ethylene/1-hexene(S-43) copolymers were studied in a manner analogous to that established by Hsieh and Cheng. The comonomer sequence distributions of copolymer samples were obtained. The results show that these metallocene based copolymers contain a small amount of butene and hexene, and the EE and EEE sequences are dominant.

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The bioaccumulation of phthalate acid esters (PAEs) from industrial products and their mutagenic action has been suggested to be a potential threat to human health. The effects of the most frequently identified PAE, Di-n-butyl phthalate (DBP), and its biodegradation, were examined by comparison of two small scale plots (SSP) of integrated vertical-flow constructed wetlands. The influent DBP concentration was 9.84 mg l(-1) in the treatment plot and the control plot received no DBP. Soil enzymatic activities of dehydrogenase, catalase, protease, phosphatase, urease, cellulase, beta-glucosidase, were measured in the two SSP after DBP application for 1 month and 2 months, and 1 month after the final application. Both treatment and control had significantly higher enzyme activity in the surface soil than in the subsurface soil (P < 0.001) and greater enzyme activity in the down-flow chamber than in the up-flow chamber (P < 0.05). In the constructed wetlands, DBP enhanced the activities of dehydrogenase, catalase, protease, phosphatase and inhibited the activities of urease, cellulase and beta-glucosidase. However, urease, cellulase, beta-glucosidase activities were restored 1 month following the final DBP addition. Degradation of DBP was greater in the surface soil and was reduced in sterile soil, indicating that this process may be mediated by aerobic microorgansims. DBP degradation fitted a first-order model, and the kinetic equation showed that the rate constant was 0.50 and 0.17 d(-1), the half-life was 1.39 and 4.02 d, and the r(2) was 0.99 and 0.98, in surface and subsurface soil, respectively. These results indicate that constructed wetlands are able to biodegrade organic PA-Es such as DBP. (c) 2005 Elsevier Ltd. All rights reserved.

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通过Pt羰基簇合物在N2气氛下于150℃热分解制得了无定形的碳载纳米Pt催化剂.发现甲醇在这种催化剂上氧化的起始电位和峰电位均比在传统的液相还原法制得的Pt/C催化剂上发生了负移,峰电流也有明显的增加,且稳定性好.表明通过Pt羰基簇合物热分解制备Pt/C催化剂是一种较好的制备甲醇氧化电催化剂的方法.

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从海洋动植物中寻找和筛选具有药用价值的活性先导化合物是海洋药物研发极为重要的理论基础研究。基于中国东南热带和亚热带沿海海域丰富的生物资源,本工作以化学分析和生物活性筛选为导向,以黄海海域习见的绿藻束生刚毛藻、南海三亚附近海域的圆裂短足软珊瑚、海绵Pseudoceratina sp.及广西沿海滩涂的盐生植物海刀豆四种海洋生物为样品,应用现代分析和检测手段对其次生代谢产物及其生物活性进行较系统的研究。 综合利用现代色谱手段和波谱技术,从上述目标生物样品中共分离并结构鉴定化合物74个,其中新化合物10个,新天然产物1个,这一新发现原则性结果,属国内外首次报道。1.对黄海海域束生刚毛藻C. fascicularis的化学成分及其生物活性进行了首次研究,从中得到叶绿素类新化合物Porphyrinolactone 1和新天然产物 20-Chlor-(132-S)-hydroxyphaeophytin a 2,在避光条件下对叶绿素类化合物进行体外NF-κB活性抑制筛选实验, 结果表明化合物1-6对NF-κB都有显著的抑制活性;对叶绿素类化合物首次进行体外蛋白酶体ChT-L的抑制活性实验筛选,化合物2和4对蛋白酶体ChT-L表现出显著的抑制活性,在浓度为50μM时,抑制率分别为70%和73.5%,并对其立体构型和生物活性的构效关系进行探讨;首次从该属得到环阿尔廷三萜类化合物7—12;对所得化合物7—15在浓度为1μg/mL时对肿瘤细胞部分靶蛋白酶的抑制活性测定结果表明,这些化合物对不同的靶蛋白酶表现出较强的抑制活性。2. 从南海圆裂短足软珊瑚中发现孕甾及其糖苷类新化合物22—27。3. 南海海绵Pseudoceratina sp.中发现溴代酪氨酸生物碱类新化合物41—42,组胺酸生物碱类新化合物43,并对其生源关系进行探讨。4. 首次对海刀豆C. maritime的化学成分进行研究,发现紫檀素类化合物61—63,异黄酮4个64—67;对该类化合物61—67首次进行NF-κB和蛋白酶体ChT-L的抑制活性筛选,其中化合物63表现出较强的NF-κB的抑制活性。

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Growth rates, measured as shell length and body weight daily growth, were studied in the eight families of Pacific abalone, Haliotis discus hannai Ino, reared at 12, 16 and 20 degrees C for 40 d respectively. The results show that J(1)Rh family grew the best at 12 degrees C, with growth rates of (32.88 +/- 4.66) mu m/d and (5.24 +/- 1.84) mg/d. C(1)Jm family had the highest growth rates of (58.00 +/- 2.00) mu m/d and (9.71 +/- 1.21) mg/d at 16 degrees C. J(1)Jm family ranked the first at 20 degrees C, with growth rates of (66.00 +/- 1.76) mu m/d and (10.99 +/- 0.34) mg/d. RjRh family had the slowest growth rates at all three temperatures. Shell length growth rates were 18.25, 33.00 and 43.13 mu m/d respectively, while body weight growth rates were 2.47, 2.56 and 4.75 mg/d respectively. Both temperature and family had significant effect on growth rates (P<0.05). At 16 and 20 degrees C, maternal effects on growth rates were not significant (P>0.05), but paternal effects on growth rates were significant (P<0.05). Results of this study indicate genetic difference among the families and importance of selecting male breeders in the commercial hatchery.

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The objective was to identify an appropriate cryoprotectant and protocol for vitrification of red sea bream (Pagrus major) embryos. The toxicity of five single-agent cryoprotectants, dimethyl sulfoxide (DMSO), propylene glycol (PG), ethylene glycol (EG), glycerol (GLY), and methyl alcohol (MeOH), as well as nine cryoprotectant mixtures, were investigated by comparing post-thaw hatching rates. Two vitrifying protocols, a straw method and a solid surface vitrification method (copper floating over liquid nitrogen), were evaluated on the basis of post-thaw embryo morphology. Exposure to single-agent cryoprotectants (10% concentration for 15 min) was not toxic to embryos, whereas for higher concentrations (20 and 30%) and a longer duration of exposure (30 min), DMSO and PG were better tolerated than the other cryoprotectants. Among nine cryoprotectant mixtures, the combination of 20% DMSO + 10% PG + 10% MeOH had the lowest toxicity after exposure for 10 min or 15 min. High percentages of morphologically intact embryos, 50.6 +/- 16.7% (mean +/- S.D.) and 77.8 +/- 15.5%, were achieved by the straw vitrifying method (20.5% DMSO + 15.5% acetamide + 10% PG, thawing at 43 degrees C and washing in 0.5 M sucrose solution for 5 min) and by the solid surface vitrification method (40% GLY, thawing at 22 degrees C and washing in 0.5 M sucrose solution for 5 min). After thawing, morphological changes in the degenerated embryos included shrunken yolks and ruptured chorions. Furthermore, thawed embryos that were morphologically intact did not consistently survive incubation. (C) 2007 Elsevier Inc. All rights reserved.

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重离子束治癌是当今放射治疗中最科学、最先进、最有效的方法,是有代表性的高技术。目前仅有美、日、德实现了该技术,并已取得常规疗法难以实现的疗效。我国近年来开展了“重离子束治癌技术的基础研究”,其中,放射生物学及机理研究是重要内容。本论文从细胞、DNA分子、以及动物个体的三个不同层次上分别研究了重离子束治癌相关的生物学问题。在细胞研究方面。采用HeLa、B 16两种细胞分别研究了X一射线和重离子在水介质中入射的深度与相应细胞的存活率(1一失活率),结果表明:X一射线对细胞的损伤随深度而逐渐衰减(或细胞存活随深度逐渐增加),而重离子对细胞的损伤则为Bragg曲线(或细胞存活为倒Bragg曲线)。研究了25MeV/u ~(40)Ar~(14+)辐照人肝癌细胞SMMC一7721的微核及存活的动态变化,结果表明: 单次照射与分次照射的微核率随时间的变化规律在96h内没有明显区别,受照(单次、分次) 肝癌细胞的存活数随时间表现出衰减趋势,微核率与细胞存活数关系的动态变化为负相关性。研究了6MV X-射线和125.5keV/μm的重离子辐照B 1 6、V79细胞的2Gy存活率(SF2),结果表明:B16和V79细胞的存活率(P<0.01)依赖于不同的辐射性质(X-射线、~(12)C离子),其X-射线与~(12)C离子辐射这两种细胞的存活率之比分别为5.4和1.43,即~(12)C离子辐射增强了X-射线抗性细胞系的敏感性,从而显示了重离子治疗癌症的优势。研究了125.5keV/um的碳离子辐照小鼠黑色素瘤B16、人的宫颈癌HeLa、中国仓鼠肺V79、人的肝癌SMMC-7721四种细胞的相对生物学效率(RBE),得.到了RBE依赖于细胞种类的关系、RBE随细胞存活水平的升高而增加的关系、以及当LET≥125.5keV/μm时,RBE随着LET的增大而变小的关系。在DNA分子研究方面。研究了125.5keV/μm~(12)C~(6+)辐照小鼠黑色素瘤B 16、中国仓鼠肺V79、人的宫颈癌HeLa、人的肝癌SMMC一7721细胞的灵敏度(由D50表示)、DNA双链断裂(DSB)和DNA双链断裂片段分布,结果表明:细胞敏感性与DNA双链断裂之间没有一致的关系,提出了细胞辐射敏感性的一种可能的分子机理,即DNA序列敏感性位点协同DNA双链断裂互补性机理。由此解释了四种细胞系的不同敏感性问题。在动物个体研究方面。研究了57.28MeV/u氧离子50Gy一次性局部照射对B16黑色素瘤小鼠肿瘤生长的抑制作用,并观测了受照小鼠的死亡情况,结果表明:照射B16黑色素瘤后第10天观察,肿瘤生长延迟为6天、肿瘤抑制率为66%,耐受剂量小于50Gy。研究了50MeV/u ~(12)C~(6+)离子辐照对小鼠移植性肿瘤S180的抑制作用、控制率、治愈率和病理组织学变化,结果表明:各剂量组对S180肉瘤的抑制作用均大于90%,高剂量组抑瘤作用明显强于低、中剂量组(P

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人工潜流湿地由 3个面积各为 90 0m2 的芦苇床组成 ,平均布水量分布为 6m3 d、18m3 d和 30m3 d .进水污染物平均浓度为 :COD 40 1 0 8mg L ,BOD531 88mg L ,矿物油 2 4 6 7mg L ,TN 11 6 7mg L .经潜流湿地处理后上述污染物分别减少了COD6 7 2 5 %— 80 77% ,BOD580 0 2 %— 89 0 5 % ,石油类 78 0 0 %— 88 45 % ,TN 75 32 %— 82 43 % .经检测 ,试验期间潜流湿地的渗透率为 0 5 2m d ,在这种条件下潜流湿地的耐冲击负荷强 ,出水水质稳定

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采用Cr/Al催化体系,成功地合成了全同1,2-聚丁二烯(PBD),并用DSC法、X-射线衍射、红外光谱及~(13)C-NMR的方法进行结构与物性测定,得如下结果:全同1,2-PBD的熔点为124.3℃;三角晶系中,分子链成了螺旋,晶胞参数为a=17.3A,c= 6.5A;在红外光谱中,其特征谱带出现在694.4 cm~(-1)处;在~(13)C-NMR谱中仅出现四条谱峰,其化学位移分别为142.51、111.56、39.26、37.43 ppm。全同1,2-PBD的~(13)C-NMR谱提供的实验数据表明,在~(13)C-NMR谱中1,2-PBD-CH二碳十个五元组谱峰的归属是有别于Elgert、Kumar已有的归属。它属于一种新的归属,与半经验方法所推演的结果相符。它恰巧同聚丙烯侧甲基五元组谱峰的归属一致。采用半经验方法研究了1,2-PBD的~(13)C-NMR增中CH二碳五元组、CH_2-碳四元组及六元组共振谱峰,同时讨论了模型链的链长、温度以及立构序列的排列对各立构序列键概率的影响,求得了相应的r值。同时采用经验方法对1,2-PBD的~(13)C-NMR谱中CH_2=碳、CH-碳五元组及CH_2-碳四元组谱峰做了归属。两种方法对CH_2-碳谱峰的归属得到了一致的结果。

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A two-dimensional (2-D) vortex-induced vibration (VIV) prediction model for high aspect ratio (LID) riser subjected to uniform and sheared flow is studied in this paper. The nonlinear structure equations are considered. The near wake dynamics describing the fluctuating nature of vortex shedding is modeled using classical van der Pol equation. A new approach was applied to calibrate the empirical parameters in the wake oscillator model. Compared the predicted results with the experimental data and computational fluid dynamic (CFD) results. Good agreements are observed. It can be concluded that the present model can be used as simple computational tool in predicting some aspects of VIV of long flexible structures. (C) 2008 Elsevier Ltd. All rights reserved.

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土壤氮素矿化是陆地生态系统氮素转化的重要组成部分。不同的土地利用(管理)方式会改变土壤氮素转化过程,影响土壤肥力的保持,进而可能造成土壤内氮素渗漏流失。为系统了解内蒙古农牧交错区土壤氮素转化的特点,本实验采用原位培养顶盖埋管法进行野外培养,每间隔一个月定期取样,于2004年7月-2006年10月在植物所恢复生态学实验站进行了两个试验,1:选择农牧交错区四种有代表性的土地类型(围封样地:FS,放牧样地:GS,弃耕地:AF,和农田:CF),比较土地利用方式之间氮素矿化的异同;2:在施肥样地通过不同施肥处理(F0: 1g N m-2, F1: 1g N m-2, F2: 2g N m-2, F3: 4g N m-2, F4: 8g N m-2, F5: 16g N m-2, F6: 32g N m-2, F7: 64g N m-2) 的土壤氮素转化动态,确定过度放牧的典型草原围封禁牧后,植被恢复过程中最适宜的施肥量。主要结论如下: 1. 与试验初期相比,整个非生长季围封样地、弃耕地和农田的铵态氮和无机氮含量逐渐降低,培养结束时铵态氮含量分别减少了67.04%,77.31%和70.54%,而放牧地的含量增加1.63%。围封样地、放牧地、弃耕地和农田的硝态氮含量分别增加了61.61%,376.43%,199.75%和133.16%。非生长季四种土地类型的土壤氮素转化速率主要受温度影响。围封样地、放牧地、弃耕地和农田非生长季矿化速率均值分别为-0.016,0.0429,-0.0051和-0.0030 μg g-1 d-1。硝化速率均值变幅为-0.43-0.17 μg g-1d-1。 2. 与没有冷冻而融化的土壤相比,冻融显著影响土壤无机氮含量的变化。只有在较低的土壤温度条件下冷冻以后,融化才会促进土壤氮素矿化。不同的冷冻时间长度下融化均会促进土壤硝化速率。土壤温度、土壤含水量变化是影响氮素转化速率的重要因子。 3. 四种土地类型的年日均矿化速率为放牧样地>农田>弃耕地>围封样地,分别为0.25,0.11,0.10,0.06μg g-1d-1,其年平均速率分别为11.65,5.50,5.00和2.46g m-2 y-1,而年日平均硝化速率分别为0.27,0.095,0.097和0.05μg g-1d-1。其中生长季日均矿化速率和日均硝化速率均为其年日均速率的两倍。因此,生长季形成的矿化氮是全年的93%,而形成的硝态氮占全年的86%。四种土地类型年均矿化氮的累积量平均为615.04 kg ha-1,而硝化作用的累积量变幅为230.44-1218.86 kg ha-1。四种土地类型的矿化速率和硝化速率的季节动态变化与气候因子的变化一致。 4. 不同施肥处理对典型草原土壤氮素转化均有显著影响。与对照相比,少量施肥(F1,F2)土壤铵态氮,硝态氮和无机氮含量分别减少20.57%,11.18%和17.18%。当施肥量大于F4(8g N m-2)时,随施肥量增加土壤铵态氮,硝态氮和无机氮含量增加18%-1191%。除F5(16g N m-2)外,与对照相比,随施肥量增加,土壤矿化速率增加了5-21倍。4 g N m-2 (F3)左右是典型草原生态系统比较合适的施肥量。 5. 氨气挥发速率的季节动态特征与气象因子的变化一致,其速率变幅为17.65 - 1228.39µg m-2 d-1,其中7月挥发量占全年的37%。与对照相比,少量施肥氨气挥发速率降低了1-2%,施肥量大于F3 (4g N m-2),速率增加了1-4倍。实验期间总的流失量变幅为23.76-84.91mg m-2,而且通过氨气挥发流失量低于土壤全氮的3%。氨气挥发不是典型草原过量氮素流失的主要方式。 6. 氮素限制的典型草原,植被恢复过程中外源氮素添加阈值为:4 g N m-2 (F3)。与对照相比,短期施肥(3年)不会显著影响根系碳储量和土壤碳氮储量。施肥处理的土壤硝态氮和无机氮含量显著增加,说明施肥显著刺激硝化作用。典型草原60%植物根系主要分布在地下0-10cm,这里的碳储量占地下储量(0-50cm)的63%以上。随土壤深度增加,土壤全氮,全碳,无机氮储量降低。而铵态氮储量和可利用的无机氮含量随土壤深度增加,说明植物根系主要吸收利用上层可利用氮素,而且下层氮素矿化速率降低。

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通过生物信息学和系统发育学分析,研究了苦味受体和甜味/鲜味受体的进化途径。结果显示,苦味受体 和甜味/鲜味受体在进化上具有远相关,并且具有不同的进化途径,提示这可能是导致这些受体具有不同功能,传 导不同味觉的原因。