7 resultados para 82-558
em Chinese Academy of Sciences Institutional Repositories Grid Portal
Resumo:
肺癌是全世界癌症死亡中的一个主要的原因。除吸烟外,一些肺癌患者的发病与氡气污染相关。该研究采用包括染色体分选、正向和反向染色体涂色技术,分析了两株肺腺癌细胞系A549和GLC-82的核型特征。A549和GLC-82细胞系都属于非小细胞肺癌细胞系,但诱因不同,后者来源于一个长期生活在氡气污染环境肺癌病人的癌组织。染色体涂色结果表明,这两株肺癌细胞系发生了复杂的染色体重排。在A549和GLC-82细胞系中,除正常染色体拷贝数变化外,还分别存在13条和24条畸变染色体。约一半的畸变染色体是通过非相互易位形成的,其余的畸变染色体则是通过一些正常染色体的片段缺失或重复而产生的。尽管这两株肺癌细胞系都没有共同的畸变染色体,但它们似共享两个染色体易位断裂点:HSA8q24和12q14。
Resumo:
由于其独特的电子结构,笼内金属富勒烯(碳笼内包容金属原子)的研究一直吸引着人们极大的兴趣,目前已经合成并分离出的笼内金属富勒烯主要包括碳笼内包容铱、钪、镧系原子等。在本论文中我们利用质谱技术对笼内金属富勒烯Gd_2@C_(82)气相离子行为和C_(60)与丙烯酸甲酯气相离子反应进行研究,X光电子能谱对碳笼内轧原子的价态进行研究。笼内金属富勒烯Gd_2@C_(82)是利用电弧放电法合成的。将碳份与三氧化二钆 (C:Gd=1:100, 摩尔比)灌入碳棒,将为棒前处理后,在氦气份保护下进行放电。通过对空心富勒烯在不同沸点的溶解情况进行了研究,发现大碳数的空心富勒烯在高沸点容剂中有较大的溶解度。利用两步高温高压法,既先利用1,2,4-三甲2基苯对大碳数的空心富勒烯进行分离,然后利用吡啶对笼内金属富勒烯进行提取。利用三种不同的质谱电离方式:电喷雾 (ESI),激光解析飞行时间(LDI-TOF),共振电子捕获技术(REC)来研究笼内金属富勒烯的气相离子特征。实验结果表明LDI-TOF和REC电离技术得到的质谱谱图中,笼内金属富勒烯和空心富勒烯均出现分子离子峰,但在电喷雾质谱谱图中只有笼内金属富勒烯出现分子离子峰。结合这一实验结果和理论分析说明碳笼内钆离子偏离碳中心位置。通过对比笼内金属富勒烯Gd@C_(82)和三氧化二钆中钆离子的光电子能谱谱图,Gd@C_(82)的电子结构应表示为Gd~(3+)@C_(82)~(3-)。利用四极杆质谱仪对C_(60)分子[C_(60)H]~+和加成产物为[C_(60)C_4H_3O]~+,后者是丙烯酸甲酯分子经过α短裂后与质子化[C_(60)H]~+ 发生加成反应所得的产物,在限制性Hartree-Fock条件下,采用AM1半经验量子化学计算方法对加成产[C_(60)C_3H_3O]~+八种可能结构的产物进行计算,得出了三种可能的最稳定的环加成同分异构体。
Resumo:
黄龙世界自然遗产地岷江冷杉林(Abies faxoniana)生境类型多样,群落结构复杂,群落植物种类组成多样性丰富。揭示不同生境的生物多样性及其差异是认识生物多样性格局、形成及维持机制的前提和进行多样性保育的基础。本文采用样方法对黄龙钙化滩生境、阴坡非钙化生境及半阳坡非钙化生境的岷江冷杉原始林植物群落结构及植物多样性进行了研究。结果表明: 黄龙岷江冷杉林具有明显的复层异龄结构,垂直结构明显,乔木、灌木、草本、苔藓层次分明。共发现高等植物386 种,其中维管植物46 科103 属163 种,苔藓植38 科83 属物223 种。各层片结构及物种组成如下: (1)钙化滩生境、阴坡非钙化生境、半阳坡非钙化生境分别发现乔木18 种、13种、8 种。乔木层均可分为两个亚层,第一亚层优势种均为岷江冷杉,第二亚层主要为岷江冷杉异龄树或其它大高位芽物种。钙化滩生境第一亚层除优势种岷江冷杉外混生有巴山冷杉(Abies fargesii)、粗枝云杉(Picea asperata)以及阔叶树种白桦(Betula platyphylla)等,第二亚层主要为岷江冷杉异龄树;阴坡非钙化生境第一亚层除优势种岷江冷杉外间有巴山冷杉和白桦,第二亚层物种主要为川滇长尾槭(Acer caudatum var. prattii);半阳坡非钙化生境第一亚层除优势种岷江冷杉外混生有巴山冷杉,第二亚层主要为岷江冷杉异龄树。依乔木层优势种的差异,钙化滩生境及半阳坡非钙化生境为岷江冷杉纯林,阴坡非钙化生境为岷江冷杉-川滇长尾槭混交林。不同生境乔木层郁闭度、乔木密度、树高结构、直径结构均存在差异。 (2)钙化滩生境发现灌木41 种,平均盖度为18.49±1.72(%),平均高度为52.12±4.45(cm),优势种为直穗小檗(Berberis dasystachya);阴坡非钙化生境发现灌木30 种,平均盖度为29.33±2.56 (%),平均高度为119.55±8.01 (cm),优势种为箭竹 (Fargesia spathacea) 、唐古特忍冬(Lonicera tangutica) 和袋花忍冬(Lonicera saccata);半阳坡非钙化生境发现灌木29 种,平均盖度为31.35±1.93 (%),平均高度为107.55±4.24 (cm),优势种为箭竹(Fargesia spathacea)。不同生境灌木层结构和物种组成多样性差异显著,钙化滩生境的灌木盖度、高度总体上较非钙化的坡地生境低, 钙化滩生境灌木以小型叶的落叶灌木为主,沟两侧非钙化的坡地生境上则发育了丰富箭竹。 (3)钙化滩生境发现草本46 种,平均盖度为7.18±0.79 (%),平均高度为5.04±0.26(cm),以山酢浆草(Oxalis griffithii)为优势种;阴坡非钙化生境发现草本物种71 种,平均盖度达29.04±2.31(%),平均高度为9.08±0.52(cm),以钝叶楼梯草(Elatostema obtusum)、山酢浆草为优势种;半阳坡非钙化生境草本物种50 种,平均盖度为以8.79±0.82(%),平均高度为7.67±0.43 (cm),以扇叶铁线蕨(Adiantum flabellulatum)、双花堇菜(Viola biflora)、华中蛾眉蕨(Lunathyrium shennongense)、山酢浆草为优势种。阴坡非钙化生境草本层片发育良好,多样性最为丰富,盖度和物种丰富度均显著高于钙化滩生境和半阳坡非钙化生境。 (4)钙化滩生境发现苔藓物种140 种,平均盖度达84.25±1.30 (%),以仰叶星塔藓(Hylocomiastrum umbratum) 等大型藓类为优势种;阴坡非钙化生境发现苔藓物种115 种,平均盖度为79.29±1.64 (%),以刺叶提灯藓(Mnium spinosum)、大羽藓(Thuidium cymbifolium)、毛尖燕尾藓(Bryhnia trichomitra)等个体较小的物种为优势种;半阳坡非钙化生境发现苔藓物种91 种,平均盖度为60.64±1.93 (%),也以刺叶提灯藓为优势种。 (5)钙化滩生境、阴坡非钙化生境、半阳坡非钙化生境的物种数分别为234 种、221 种、175 种。乔木层的Shannon-Wiener 指数分别为0.75 ±0.12、1.87±0.12、1.78±0.07(灌木层,0.44±0.08、1.71± 0.15、2.49±0.06;草本层,0.33±0.13、1.31±0.15 、2.15±0.08; 苔藓层1.30±0.11、2.08±0.04、1.73±0.11,);Pielou 均匀度指数分别为0.45±0.05、0.29±0.06、0.28±0.08(灌木层,0.75±0.03、0.68±0.05、0.52±0.06;草本层,0.68±0.02、0.77±0.02、0.74±0.02;苔藓层,0.40±0.03、0.63±0.02、0.52±0.03);Simpson's 优势度指数分别为0.63±0.06、0.78±0.04、0.83±0.07(灌木层,0.21±0.03、0.28±0.05、0.45±0.06;草本层,0.25±0.02、0.12±0.01、0.17±0.01;苔藓层,0.45±0.04、0.18±0.01、0.31±0.04)。三种生境间乔木层、草本层的Sorenson 群落相似性系数较低, 灌木层、苔藓层的的Sorenson 群落相似性系数较高。 综上所述,黄龙岷江冷杉林的群落结构、植物多样性在三种生境间存在差异性,这将意味着我们在进行黄龙世界自然遗产地的森林经营管理时要较多地关注岷江冷山林群落在不同生境中的差异性。 There were multiplex habitat types, complicated community structure and abundant species composition in the Huanglong World Natural Heritage Site. Uncovering the differences of biodiversity among different habitats was a precondition to understand the distribution, formation and sustaining mechanism of the biodiversity, and the foundation of biodiversity conservation. In the present study, using plenty of quadrants, we investigated the community structure and the biodiversity of the primitive Abies faxoniana forest in different habitats (travertine bottomland, semi-sunny-slope non-calcified habitat and shady-slope non-calcified habitat) in the Huanglong World Natural Heritage Site. The main results are as follows: All the primitive Abies faxoniana forests in the three habitats were uneven-aged with obvious vertical structure including tree layer, shrub layer, herb layer and bryophyte layer. A total of 386 higher plants including 163 vascular plant species (103 generic, 46 families) and 223 bryophyte species (83 generic, 38 families) were investigated. The structure and species composition of each layer are as follows: (1) There were 18, 13 and 8 tree species in travertine bottomland, shady-slope non-calcified habitat and semi-sunny-slope non-calcified habitat, respectively. The tree layers in all habitats can be divided into two clear sub-layers. The upper tree layers were dominated by Abies faxoniana, and the lower tree layers were dominated by uneven-aged Abies faxoniana or other phanerophytes species. There were Abies fargesii , Picea asperata and Betula platyphylla besides the dominated species (Abies faxoniana) in the upper tree layer in travertine bottomland, and the lower tree layers were dominated by uneven-aged Abies faxoniana; There were Abies fargesii and Betula platyphylla besides the dominated species (Abies faxoniana) in the upper tree layer in shady-slope non-calcified habitat, and the lower tree layers were dominated by Acer caudatum var. prattii; There was Abies fargesii besides the dominated species (Abies faxoniana) in the upper tree layer semi-sunny-slope non-calcified habitat, and the lower tree layers were dominated by uneven-aged Abies faxoniana. According to composition percentage of dominate species in tree layer, both the forest in travertine bottomland and in semi-sunny-slope non-calcified habitat could be ranked as pure forest, and the forest in shady-slope non-calcified habitat could be ranked as mingled forest. There were significant differences in crown density, plant density, height structure and diameter structure among the three habitats. (2) A total of 41 shrub species (average coverage 18.49±1.72%; average height 52.12±4.45 ㎝)were found in travertine bottomland, and the dominate species was Berberis dasystachya; A total of 30 shrub species (average coverage 29.33±2.56 %;average height 119.55±8.01 ㎝)were found in shady-slope non-calcified habitat, and the dominate species was Fargesia spathacea, Lonicera tangutica and Lonicera saccata. A total of 29 shrub species (average coverage 31.35±1.93%; average height 107.55±4.24 ㎝) were found in semi-sunny-slope non-calcified habitat, and the dominate species was Fargesia spathacea. There were significant differences in structure and species diversity of the shrub layers among the three habitats. The coverage and height of shrub had lower value in travertine bottomland than in two non-calcified habitats. Moreover, travertine bottomland was dominated by deciduous shrub species with microphyll and non-calcified habitats developed abundant Fargesia spathacea species. (3) A total of 46 herb species (average coverage 7.18±0.79%;average height 5.04±0.26 ㎝)were found in travertine bottomland, and the dominate species was Oxalis griffithii; A total of 71 herb species (average coverage 29.04±2.31%;average height 9.08±0.52 ㎝)were found in shady-slope non-calcified habitat, and the dominate species was Elatostema obtusum and Oxalis griffithii. A total of 50 herb species (average coverage 8.79±0.82%;average height 7.67±0.43 ㎝) were found in semi-sunny-slope non-calcified habitat, and the dominate species was Adiantum flabellulatum, Viola biflora, Lunathyrium shennongense and Oxalis griffithii. Herb layers developed well in shady-slope non-calcified habitat and had the higher species richness and coverage than travertine bottomland and semi-sunny-slope non-calcified habitat. (4) A total of 140 bryophyte species (average coverage 84.25±1.30%)were found in travertine bottomland, and the dominate species was big bryophyte species such as Hylocomiastrum umbratum and so on; A total of 115 bryophyte species (average coverage 79.29±1.64%)were found in shady-slope non-calcified habitat, and the dominate species was small bryophyte species such as Mnium spinosum, Thuidium cymbifolium, Bryhnia trichomitra and so on. A total of 91 bryophyte species (average coverage 60.64±1.93%) were found in semi-sunny-slope non-calcified habitat, and the dominate species was Mnium spinosum. (5) There were 234, 221 and 175 plant species in travertine bottomland, shady-slope non-calcified habitat and semi-sunny-slope non-calcified habitat, respectively. Shannon-Wiener index of the tree layer was 0.75 ±0.12, 1.87±0.12 and 1.78±0.07 (the shrub layer, 0.44±0.08, 1.71± 0.15 and 2.49±0.06; the herb layer, 0.33±0.13, 1.31±0.15 and 2.15±0.08; the bryophyte layer, 1.30±0.11, 2.08±0.04 and 1.73±0.11.) for the three habitats, respectively; Pielou index of the tree layer was 0.45±0.05, 0.29±0.06 and 0.28±0.08 (the shrub layer, 0.75±0.03, 0.68±0.05 and 0.52±0.06; the herb layer, 0.68±0.02, 0.77±0.02 and 0.74±0.02; the bryophyte layer, 0.40±0.03, 0.63±0.02 and 0.52±0.03.) for the three habitats, respectively. Simpson's index of the tree layer was 0.63±0.06, 0.78±0.04 and 0.83±0.07 (the shrub layer, 0.21±0.03、0.28±0.05、0.45±0.06; the herb layer, 0.25±0.02, 0.12±0.01 and 0.17±0.01; the bryophyte layer, 0.45±0.04, 0.18±0.01 and 0.31±0.04.) for the three habitats, respectively. There were low Sorenson index both in the tree layer and in the herb layer among the three habitats, whereas, high Sorenson index occurred both in the shrub layer and in the bryophyte layer. To sum up, there were differences both in community structure and plant diversity among the three different habitats, which means that we should pay more attention to habitats heterogeneities of the primitive Abies faxoniana forest when we take action to manage the forest in the Huanglong World Natural Heritage Site.
Resumo:
Differential cross sections for the elastic scattering of halo nucleus He-6 on proton target were measured at 82.3 MeV/u. The experimental results are well reproduced by optical model calculations using global potential KD02 with a reduction of the depth of real volume part by a factor of 0.7. A systematic analysis shows that this behavior might be related to the weakly bound property of unstable nuclei.
Resumo:
Endohedral metallofullerenes Ce@C-82, Ce-2@C-80, Nd@C-82 and Nd-2@C-80 undergo gas phase ion/molecule reactions with the ion system from self-chemical ionization of vinyl acetate, and exohedral derivatives are thus generated, A new heterocycle is formed from metallofullerenes and a C2H3O+ cation, Endohedral metallofullerenes show much higher reactivities than empty fullerenes during the association and the charge and proton transfer processes, The strong electron-donating character of endohedral metallofullerenes is due to their unique super-atom-like electronic structures. (C) 1997 by John Wiley & Sons, Ltd.
Resumo:
A highly discriminating molecular topological index, EAID, is proposed based on the extended adjacency matrix. A systematic search for degeneracy was performed for 3 807 434 alkane trees, 202 558 complex cyclic or polycyclic graphs, and 430 472 structures containing heteroatoms. No counterexamples (two or more nonisomorphic structures with the same EAID number) were found. This is a hitherto unheard of power of discrimination. Thus EAID might be possibly used as supplementary reference for CAS Registry Numbers for structure documentation.