11 resultados para 13077-065

em Chinese Academy of Sciences Institutional Repositories Grid Portal


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目的研究蜱类抗血小板集聚的生物活性成分, 了解其与其宿主相互作用的分子机制。方法用葡聚糖 Sephadex G-50 凝胶过滤及高效液相从半饱吸血的中华硬蜱(Ixodes sinensis) 唾液腺中分离纯化具有血小板集聚抑制活性 的蛋白质, 用飞行质谱测定该抑制剂的分子量, 并用兔富血小板血浆研究其血小板集聚抑制活性。结果通过液相分离, 从中华硬蜱唾液腺中得到了一种血小板集聚抑制剂, 用飞行质谱测定该抑制剂的相对分子质量(M r ) 为8 065。该抑制 剂对二磷酸腺苷(ADP) 诱导的血小板集聚表现强烈的抑制活性, 在浓度为10 μg/mL 时, 可以抑制90% 以上的血小板集 聚。结论首次分离获得中华硬蜱唾液腺血小板集聚抑制剂, 该抑制剂对硬蜱顺利获取宿主血餐至关重要。

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实验采用水平板淀粉凝胶电泳技术,对中国地方猪五大类型9个品种、1个引入品种共201个个体进行了遗传多样性分析。共分析遗传座位30个,其中只有MDH、PEPB、AK、6PGD、ADA、PHI 6个座位具有多态性。中国主要地方猪品种的多态座位百分比P=0.200,平均杂合度H=0.065,平均等位基因数A=1.300。根据基因频率采用PHYLIP3.5c软件包计算Nei氏遗传距离,然后用“NEIGHBOR”程序分别构建NJ和UPGMA系统树。

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We examined protein polymorphism of 20 native pig breeds in China and 3 introduced pig breeds. Thirty loci have been investigated, among which six loci were found to be polymorphic. Especially, the polymorphism of malate dehydrogenase (MDH), adenylate kinase (AK), and two new alleles of adenosine deaminase (ADA) had not been reported in domestic pigs and wild pigs. The percentage of polymorphic loci (P), the mean heterozygosity (H), and the mean number of alleles (A) are 0.200, 0.065, and 1.300, respectively. The degree of genetic variability of Chinese pigs as a whole was higher than that of goats, lower than that of cattle and horses, and similar to that of sheep. Using the gene frequencies of the 30 loci, Nei's genetic distance among the 20 native breeds in China and 3 introduced pig breeds was calculated by the formula of Nei. The program NEIGHBOR in PHYLIP 3.5c was chosen to construct an UPGMA tree and a NJ tree. Our results show that, of the total genetic variation found in the native pig breeds in China, 31% (0.31) is ascribable to genetic differences among breeds. About 69% of the total genetic variation is found within breeds. Most breeds are in linkage disequilibrium. The patterns of genetic similarities between the Chinese native pig breeds were not in agreement with the proposed pig type classification.

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并苯类化合物和噻吩齐聚物是目前研究最广泛的两类p型高迁移率有机半导体材料,晶态下强分子间电子相互作用的特点使它们具有优异的电荷传输性质,作为电荷传输层制备的有机薄膜晶体管(OTFT)的器件性能已经可以和非晶硅器件(α- Si:H)相比拟(0.1~1.0 cm2/V.s)。但是,由于这两类材料具有较窄的能隙和较高的最高被占分子轨道(HOMO) 能级,容易与空气中的水、氧发生反应,而且并苯类化合物对光也非常敏感,因此它们的器件性能在空气中衰减很快。可以说,如何设计与合成兼具高迁移率和优异稳定性的OTFT材料依然是目前有机光电子研究领域面临的挑战之一。 在本论文中,我们采用较稳定的芳香基团和噻吩单元构造了三个系列杂化共轭齐聚物,通过改变芳香基团结构和引入方式,对共轭齐聚物的HOMO能级做了有效的调节,不仅提高了分子的热稳定性和化学稳定性,而且使分子的HOMO能级与金电极功函相匹配,有利于电荷的注入,获得了稳定的高迁移率有机半导体材料。 1、设计并合成了一系列含不同苯类(苯、联苯、芴和菲)中心单元的噻吩类共轭齐聚物,表征了它们基本的光谱、电化学和热行为,并作为传输层用于顶电极结构的OTFT,获得了较高的场致迁移率((1-6.7)×10-2 cm2/V.s)。引入平面刚性芳香基团有利于获得稳定的高迁移率材料。噻吩/菲杂化共轭齐聚物,即2,7二(5'正己基2,2'二噻吩5)菲(DH-TTPhTT)综合性能最佳,与在相同条件下制备的DH6T具有相当的场致迁移率(μFET = 0.065 cm2/V.s)。 2、设计并合成了一系列含菲共轭齐聚物,研究了它们的基本物理和化学性质。[2,2';7',2''] 三联菲(Ph3)可通过真空蒸镀形成高度有序的薄膜,其OTFT μFET达0.01 cm2/V.s。但是,由于其HOMO能级太低,导致器件阈值电压很高,很难进一步优化器件性能。因此,为了调节分子的HOMO能级,合成了2 ,5二(2菲基) [3,2-b]并二噻吩(PhTT)和5,5'二(2菲基) 2,2'二噻吩(PhT2)两个含噻吩化合物,成功的应用于顶电极结构的OTFT,使器件性能大幅提高。其中PhT2的μFET > 0.1 cm2/V.s; Ion/Ioff > 1×105。更重要的是,器件在空气、自然光条件下保存一个月后,μFET 、Ion/Ioff和阈值电压三个性能指标都基本没有变化,说明PhT2是目前最好的OTFT材料之一。 3、设计并合成了六个萘和硫茚封端的噻吩齐聚物,研究了它们的基本物理和化学性质。为了对分子结构—堆积方式—器件性能的关系有所认识,解析了5,5'二(2萘基) 2,2'二噻吩(NaT2),5,5''二(2萘基) 2,2':5',2''三噻吩(NaT3),5,5'二(2硫茚基) 2,2'二噻吩(TNT2)和5,5''二(2硫茚基) 2,2':5',2''三噻吩(TNT3) 的单晶结构。所有六个化合物均可形成高度有序的多晶薄膜,而且薄膜有序性随噻吩单元数的增加而提高。取决于分子长度和端基结构,它们的μFET介于0.01-0.39 cm2/V.s。和TNTn系列分子(n = 2-4)相比,NaTn系列齐聚物(n = 2-4)具有更好的器件性能。齐聚物5,5'''二(2萘基) 2,2':5',2'':5'',2'''四噻吩(NaT4)具有最好的器件性能,其场致迁移率为0.39 cm2/V.s;VT = -5 V; Ion/Ioff > 1×105,是目前性能最好的OTFT材料之一。

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对爆源近区地下混凝土管道结构在爆炸冲击载荷作用下的动力学响应开展探索性实验研究。选用钢筋混凝土管道模拟地下结构,尺寸为:$\phi_{\hbox{内}}$800mm$\times$2000mm$\times$100mm。通过实验研究定量确定爆炸振动波载荷对地下结构产生的振动效应;定性确定爆炸冲击波载荷对地下管道结构和混凝土材料产生的动态破坏效应。爆炸当量分别为50 g和100 g TNT,爆炸距离取为0.1,0.3,1,7和10m。实验主要涉及地下管道结构在小药量爆炸点近区的破坏效应与爆炸药量和爆炸距离间关系的确定;混凝土材料破坏行为与药量和爆炸距离关系的确定;爆炸冲击波的影响范围以及爆炸振动波的有效影响范围与爆源特性的关系及爆炸响应函数的确定。从小当量地下结构爆炸实验观察到:地下结构的爆炸振动响应,即振动波波长和频率不同于土介质地表的波长和频率。与地表面上建筑物的波长和频率相比,振动波长持续作用时间明显缩短,且振动频率显著提高。这与地下结构的爆炸动力学响应,特别是爆源近距离的结构动力学响应存在着本质的区别。不同的爆炸距离和当量,地下爆炸对地下结构可以产生振动和冲击两种不同特征的动力学效应。在折算距离大于0.22$\sim$0.25 m/W$^{1/3}$时,100 g TNT当量的爆炸以产生振动效应为主。在折算距离小于0.22$\sim$0.25 m/W$^{1/3}$时,爆炸主要产生冲击效应;在爆炸距离小于1.5m/W$^{1/3}$时,地下爆炸振动波对结构产生的动力学响应的明显特征是管道结构发生径向变形。而且,管道上与爆源最近点是管道变形的对称点。管道的轴向和环向动力响应表现为相应方向上的刚体振动。在爆炸距离大于1.5 m/W$^{1/3}$,如等于2.15m/W1/3的情况下,爆炸振动波对管道结构产生的动力学响应主要表现为整体振动。结构的变形特征基本消失;地下爆炸冲击波载荷对爆源近区管道结构和混凝土材料可以产生三种破坏效应:在折算距离等于0.065 m/W$^{1/3}$时,低强度的冲击波载荷仅产生结构破坏效应。实验中观察到混凝土管道只沿其轴线方向上形成贯穿性裂纹,管道内外表面均无损伤和破碎现象;当折算距离等于0.027 m/W1/3时,较强冲击波载荷既引起管道的结构破坏,也产生混凝土材料的破坏。这时观察到沿混凝土管道轴线方向上,以及与轴线成30$^\circ$至50$^\circ$范围内形成贯穿性裂纹。同时在管道内表面出现直径约为210 mm的层裂区,最大层裂厚度约为8$\sim$12 mm;当折算距离等于0.022 m/W$^{1/3}$时,爆炸强冲击波载荷主要引起的混凝土材料破坏形式表现为破碎。即在管道上以爆源最近点为中心形成直径约为370 mm的贯穿性孔洞,还观察到该孔洞周边不同方向上有长度为230$\sim$410 mm不等的数条细裂纹形成。

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The low-temperature heat capacities of cyclohexane were measured in the temperature range from 78 to 350 K by means of an automatic adiabatic calorimeter equipped with a new sample container adapted to measure heat capacities of liquids. The sample container was described in detail. The performance of this calorimetric apparatus was evaluated by heat capacity measurements on water. The deviations of experimental heat capacities from the corresponding smoothed values lie within +/-0.3%, while the inaccuracy is within +/-0.4%, compared with the reference data in the whole experimental temperature range. Two kinds of phase transitions were found at 186.065 and 279.684 K corresponding solid-solid and solid-liquid phase transitions, respectively. The entropy and enthalpy of the phase transition, as well as the thermodynamic functions {H-(T)- H-298.15 K} and {S-(T)-S-298.15 K}, were derived from the heat capacity data. The mass fraction purity of cyclohexane sample used in the present calorimetric study was determined to be 99.9965% by fraction melting approach.

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对沈阳市郊区43对蔬菜保护地与相邻的露地土壤中交换性Ca、Mg含量状况及Ca/Mg比值进行对比研究的结果表明:与露地土壤相比,保护地土壤交换性Ca平均含量下降6.38%,Ca/Mg比值下降10.34%,交换性Mg平均含量上升4.74%。蔬菜保护地及露地土壤的Ca/Mg比值与交换性Ca含量呈极显著相关(r分别为0.721和0.757,n=43,P<0.01),Ca/Mg比值与交换性Mg含量无显著相关性(r分别为-0.065和-0.117,n=43)。交换性Ca含量下降的主要原因是随蔬菜输出到系统外的Ca量相对较多、含钙肥料施用量减少及土壤pH下降;交换性Mg含量上升的主要原因是土壤中适宜的pH范围(5.0~6.5)有利于Mg以交换性形态存在,土壤中高浓度的Ca2+、K+、NH+4抑制了蔬菜对Mg2+的选择性吸收。

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Background The application of polyethylenimine (PEI) in gene delivery has been severely limited by significant cytotoxicity that results from a nondegradable methylene backbone and high cationic charge density. It is therefore necessary to develop novel biodegradable PEI derivates for low-toxic, highly efficient gene delivery.Methods A series of novel cationic copolymers with various charge density were designed and synthesized by grafting different kinds of oligoethylenimine (OEI) onto a determinate multi-armed poly(L-glutamic acid) backbone. The molecular structures of multi-armed poly(L-glutamic acid)-graft-OEI (MP-g-OEI) copolymers were characterized using nuclear magnetic resonance, viscosimetry and gel permeation chromatography. Moreover, the MP-g-OEI/DNA complexes were measured by a gel retardation assay, dynamic light scattering and atomic force microscopy to determine DNA binding ability, particle size, zeta potential, complex formation and shape, respectively. MP-g-OEI copolymers were also evaluated in Chinese hamster ovary and human embryonic kidney-293 cells for their cytotoxicity and transfection efficiency.

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The crystal structure of the title compound has been determined from single crystal X-ray diffraction. The complex crystallizes in the triclinic space group P1 with Z=2. Lattice parameters are: a = 0.7296(1), b = 1.0110(3), c = 1.2814(4) nm; alpha = 90.84(2), beta = 101.17(2), gamma = 92.52(2)-degrees. Intensity data were collected on a Nicolet R3M/E four-circle diffractometer using MoK alpha (lambda = 0.071073 nm) radiation. The structure was solved by Patterson and Fourier techniques and refined by least-squares techniques to R = 0.065. The structure of the complex consists of tetrahedral ZnCl42- anions which form a two-dimensional sheets. Tetrahedral ZnCl42- anions are sandwiched between two hydrocarbon layers which consist of [NH3(CH2)10NH3]2+ cations. Each [NH3(CH2)10NH3]2+ group is in a gauche bond between C atoms near NH3 polar heads.

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在氮限制型富营养化湖泊中,沉积多磷酸盐(Poly-P)可以用来示踪营养盐磷的输入和湖泊的富营养化过程。太湖是一个典型的磷限制型富营养化湖泊,通过对太湖表层沉积物中总有机碳(TOC)、总氮(TN)、总磷(TP)、氢氧化钠可提取磷(NaOH-P)以及Poly-P 的提取分析,初步探讨了太湖营养盐磷输入的历史记录,并揭示了该湖Poly-P 的主要来源和保存机制。太湖Poly-P 的质量浓度较低,变化范围为0.004~0.065 mg·g-1。NaOH-P 占TP 组成的22%,是太湖沉积物总磷的主要组成部分之一。结果显示,在湖泊水体藻类生物量较大和NaOH-P 是沉积物TP 重要组成部分的磷限制型湖泊中,Poly-P 也是沉积物磷汇组成的一个重要部分,同时还是一个可以反映由人为磷输入增大导致湖泊富营养化程度加剧的敏感指标。