20 resultados para 29-279

em Chinese Academy of Sciences Institutional Repositories Grid Portal


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向日葵原产自北美,通过人工培育,形成了具有不同遗传多态性的品种,是一种集观赏、药用、食用、油用于一体,经济价值很高的资源植物。前人已经利用传统育种、辐射育种以及现代生物技术手段对向日葵种质资源的开发和保护进行了深入研究,这也加速了向日葵新品种的选育。随着离子注入等新型辐射方式的出现,离子注入对向日葵的诱变育种研究逐渐成为向日葵新品种选育的一个新增长点。另外,作为世界四大油料作物之一,向日葵种子老化问题一直存在于向日葵种质资源保存过程。向日葵种子作为向日葵的主要物质储存库,除了含有丰富的油、脂肪酸外,还含有丰富的维生素E资源。提高向日葵种子维生素E含量可以延长向日葵种子保存时间,也可以提高向日葵的经济价值。本文以向日葵种子为实验材料,分别用蛋白质组学的方法和生理方法对N+注入后向日葵种子、人工衰老向日葵种子以及向日葵种子成熟过程中维生素E代谢进行了初步分析。 对N+注入后向日葵种子蛋白质组变异研究发现,对照种子蛋白中的No.29特异蛋白与MADS盒转录因子HAM59有23.48%的匹配率;处理种子中的No.279特异蛋白与亮氨酸拉链蛋白的同源蛋白HAHB-4有23.20%的匹配率。说明离子注入能引起向日葵种胚蛋白质组水平上的变异,以期对离子注入的诱变机制进行初步探讨,为进一步探讨离子注入对于DNA及蛋白质的是否存在诱变热点提供一些初步的证据。 种子在高温和高含水量情况下曝露数天诱发的加速衰老比一般衰老引起更多的生化分解;另一方面,在长期贮存条件下的低温贮存环境和种子低含水量可能使种子处于玻璃态。种子胞质的极高粘度和低分子运动能够阻止或抑制很多有害过程。尽管种子衰老的生理机制已有大量研究,但衰老过程中的主要过程和相互作用仍未完全清楚。本文报道向日葵种子在较宽范围的含水量和温度条件下的脂过氧化、非酶蛋白糖基化对种子衰老的影响;同时,对种子玻璃态在长期贮存中对生化分解的阻滞作用并由此延长种子存活力也进行了探讨;与此同时我们借用蛋白质组学手段对加速老化的向日葵种子进行蛋白质组变异分析,结果发现随着老化程度的加深,出现部分蛋白含量随之增加,同时老化速率随之下降。通过质谱鉴定发现其中两个蛋白分别与resistance gene analog NBS4和 NBS5具有一定的同源性。因此我们推测,在加速老化过程中,亦可出现一些延缓老化的蛋白质,同时这些蛋白的出现是否标志着加速老化过程中也存在“玻璃态”有待于进一步的证实。 另外,我们以20份向日葵种质资源为实验材料,通过对维生素E含量、含油率、皮壳率以及百粒重的测定及统计分析,试图了解向日葵种质资源中维生素E含量变异及相关数据。结果表明,在20份向日葵种质资源中,油葵的维生素E含量和含油率明显高于食葵;含油率与维生素E含量在0.01水平呈极显著正相关,含油率与百粒重在0.05水平呈显著负相关;百粒重与皮壳率在0.01水平呈极显著负相关。通过初步评价,发现3份富含天然维生素E的向日葵种质。为了提高向日葵种子中维生素E含量,我们对向日葵胚胎发育过程中维生素E的积累以及短时高温对维生素E代谢的影响做了分析。我们发现,生育酚含量在开花后12到33天期间呈线性增长,并于33天后基本达到最大值,直至种子成熟。在上述生育酚增长期,我们将以每7天作为一个时间单位,对向日葵种胚发育过程进行高温处理。我们发现,高温对维生素E积累具有明显的刺激作用(以干重为基础)。但是由于在开花后12到19天之内高温处理会极大的影响干重的增加,因此当温度超过35℃时,生育酚总量还是大大下降的。然而,35℃的高温在向日葵开花后12到19天内并没有影响种胚的干重,而大大提高了单粒种子中的生育酚含量。因此,这些结果说明,我们可以调整播种时间提高向日葵中生育酚的含量,从而提高向日葵油的品质和向日葵种质的价值。

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用耳石、脊椎骨、鳃盖骨等识别和鉴定暗纹东方鲀(Takifugu obscurusAbe)的年龄,在描述其轮纹特征基础上,比较其在判读暗纹东方鲀年龄和生长特征上的异同与准确性。结果表明,耳石磨片上的轮纹特征明显、清晰且规律性强,是最好的年龄鉴定材料;脊椎骨轮纹也很清晰,但测量时有一定难度,也是较好的年龄鉴定材料;鳃盖骨上年轮较难判定,只能作为辅助材料。本文还对牙齿能否作为年龄鉴定材料进行了观测。

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记述了在中国6个典型地带土壤中鉴定到的隶属于动基片纲的29种纤毛虫,其中5种为中国土壤原生动物新记录种.这些种类是:陆生拟裸口虫,恼斜板虫,吻瓶口虫,双核管形虫,琴刀口虫,长刀口虫,长尾刀口虫,斜叶苔叶虫,神螺流苏虫,土壤肾形虫,三分肾形虫,背沟肾形虫,无规肾形虫,直立肾形虫,粗糙拟肾形虫,莫氏拟肾形虫,贪食阔庭虫,大撕拉虫,吻吴氏虫,澳洲吴氏虫,大口匙口虫,尖锐密粒虫,卡氏颠毛虫,小拟匙口虫,尖锐篮环虫,丛林拟篮环虫,有肋薄咽虫,弧形微秀体虫和凤冠齿扇虫.

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A comparative limnological study was carried out to present a snapshot of crustacean zooplankton communities and their relations to environmental factors to test whether there is a consistent relationship between crustacean biomass and trophic indicators among lake groups with similar trophic conditions. The study lakes showed a wide range of trophic status, with total phosphorus (TP) ranging from 0.008 to 1.448mgL(-1), and chlorophyll a from 0.7 to 146.1 mu g L-1, respectively. About 38 species of Crustacea were found, of which Cladocera were represented by 25 taxa (20 genera), and Copepoda by 13 taxa (I I genera). The most common and dominant species were Bosmina coregoni, Moina micrura, Diaphanosoma brachyurum, Cyclops vicinus, Thermocyclops taihokuensis, Mesocyclops notius and Sinocalanus dorrii. Daphnia was rare in abundance. Canonical correspondence analysis showed that except for four species (D. hyalina, S. dorrii, C. vicinus and M. micrura), almost all the dominant species had the same preference for environmental factors. Temperature, predatory cyclopoids and planktivorous fishes seem to be the key factors determining species distribution. TP was a relatively better trophic indicator than chlorophyll a to predict crustacean biomass. Within the three groups of lakes, however, there was no consistent relationship between crustacean biomass and trophic indicators. The possible reason might be that top-down and bottom-up control on crustaceans vary with lake trophic state. The lack of significant negative correlation between crustacean biomass and chlorophyll a suggests that there was little control of phytoplankton biomass by macrozooplankton in these shallow subtropical lakes. (c) 2007 Elsevier GmbH. All rights reserved.

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We demonstrate 1.25-1.29 mu m metamorphic laser diodes grown on GaAs by molecular beam epitaxy (MBE) using an alloy-graded buffer layer (GBL). Use of Be in the GBL is effective to reduce surface/interface roughness and improves optical quality. The RMS surface roughness of the optimized metamorphic laser is only two atomic monolayers for 1 x 1 mu m(2). Cross-sectional transmission electron microscopy (TEM) images confirm that most dislocations are blocked in the GBL. Ridge waveguide lasers with 4 mu m wide ridge were fabricated and characterized. The average threshold current under the pulsed excitation is in 170-200 mA for a cavity length of 0.9-1.5 mm. This value can be further reduced to about 100 mA by high-reflectivity coating. Lasers can work in an ambient temperature up to at least 50 degrees C. (c) 2006 Elsevier B.V. All rights reserved.

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于2010-11-23批量导入

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<正>近年来,双质子发射的现象被广泛研究。~(29)S核最外层两个质子处于2s1/2轨道,可能存在这种奇特的行为。先前的实验表明,~(29)S+~(28)Si的总反应截面有着异常大的值。这意味着~(29)S中最后2

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An experiment of a S-29 beam bombarding a Au-197 target at an energy of 49.2 MeV/u has been performed to study the two-proton correlated emission from S-29 excited states. Complete-kinematics measurements were carried out in the experiment. The relative momentum, opening angle, and relative energy of two protons, as well as the invariant mass of the final system, were deduced by relativistic-kinematics reconstruction. The Si-27-p-p coincident events were picked out under strict conditions and the phenomenon of p-p correlations was observed among these events. The mechanisms of two-proton emission were analyzed in a simple schematic model, in which the extreme decay modes like He-2 cluster emission, three-body phase-space decay, and two-body sequential emission were taken into account. Associated with the Monte Carlo simulations, the present results show that two protons emitted from the excited states between 9.6 MeV and 10.4 MeV exhibit the features of He-2 cluster decay with a branching ratio of 29(-11)(+10)%.

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L-shell X-ray spectra of Mo surface induced by Xe25+ and Xe29+ were measured. The X-ray intensity was obtained in the kinetic energy range of the incident ions from 350 to 600 keV. The relationship of X-ray intensity with kinetic energy of the projectile and its charge state were studied, and the simple explanation was given.

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A series of experiments have been performed by complete kinematics measurements to study two-proton (2p) correlated emission from the excited states of Ne-17,Ne-18 and S-28,S-29 via the Coulomb excitation by bombarding on Au-197 target. 2p and residua coincident events were picked Out under strict conditions. Visible p-p correlations were observed. It is shown that 2p can be emitted from the high-lying excited states. 2p halo may lead to 2p emission with large spectroscopy factor for the states close to or beyond the threshold.

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The nonstoichimetric Ba0.92Y2.15F8.29 submicrospheres that piled up by nanoparticles have been prepared via a solution-based method in a hydrothermal environment. The size distribution of the submicrospheres could be tuned by varying the amount of BaCl2. The fluoride source NaBF4 plays an important role in the formation of the submicrospheres. The chelator ethylenediaminetetraacetic acid regulates the growth of the primary nanoparticles as well as the aggregated submicrospheres. The photoluminescence properties of different concentrations of Eu3+-doped Ba0.92Y2.15F8.29 were investigated and the results revealed that the 8% concentration of Eu3+ ions is the optimum doping concentration and the Y3+ ions occupy the site of inversion symmetry.

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An organic-inorganic hybrid molybdenum phosphate, Na-2[{Mn(phen)(2)(H2O)} {Mn(phen)(2)}(3){(MnMo12O24)-O-v (HPO4)(6)(PO4)(2) (OH)(6)}] . 4H(2)O (phen=1,10-phenanthroline), involving molybdenum present in V oxidation state and covalently bonded transition metal coordination complexes, has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction. Deep brown-red crystals are formed in the triclinic system, space group P (1) over bar, a=16.581(l)Angstrom, b=18.354(1)Angstrom, c=24.485(2)Angstrom, alpha=80.589(l)degrees, beta=71.279(1)degrees, gamma=67.084(1)degrees, V=6493.8(8)Angstrom(3), Z=2, lambda(MoKalpha)=0.71073Angstrom (R(F)=0.0686 for 29,053 reflections). Data were collected on a Bruker Smart Apex CCD diffractometer at 293 K in the range of 1.76 < theta < 28.06degrees using omega-2theta scans technique. The structure of the title compound may be considered to be based on {Mo6O12(HPO4)(3)(PO4)(OH)(3)} units bonded together with {Mn(phen)(2)} subunits into a two-dimensional network. Two types of tunnels are observed in the solid of the title compound.