992 resultados para Polyamine Analog N-1,n-11-diethylnorspermine
Resumo:
以《生态学杂志》采用远程稿件处理系统前后的2005与2006年发表论文的收稿日期、发稿日期为案例进行统计,计算了两年每期的平均发稿周期、最短发稿周期和最长发稿周期。结果表明,自2006年《生态学杂志》采用远程稿件处理系统以来,平均发稿周期为287天,较2005年有所缩短;2006年的最短发稿周期整体上低于2005年(除2006年第3期),而且最短的发稿周期为2006年第8期的一篇论文(81天);最大发稿周期除了2006年第1期较2005年长之外,其他11期的均较2005年短。可见,远程稿件处理系统在期刊缩短发稿周期的应用中已发挥了积极作用。
Resumo:
人地关系是一个既涉及自然过程又涉及社会过程的综合概念,它是人文地理学研究的主题。从时间角度看,人地关系的演化可分为5个阶段:混沌阶段,原始共生阶段,人类对环境的顺应阶段、大规模改造阶段和人地协调共生阶段。在人地关系演进过程中,"人"通过技术手段改变了人地关系,并且"人"与"地"是密不可分的,人类对人地关系的认识也是与特定的生产力相适应的。根据区域间人地系统要素空间流的性质和方向,区际关系可分为封闭式、掠夺式、转嫁式、互补式等4种类型,当前的人地矛盾主要表现在全球尺度、国家尺度和局部地域3个不同尺度上。为协调区际人地关系,在优化区内人地关系和公平原则条件下,应强调共同利益和跨地区补偿的理念。
Resumo:
水是支撑地球生命生态系统和社会经济发展不可替代的资源。为了研究水文现象的变化和陆地水文循环的规律,水文系统方法论等到了发展。本书是关于水文非线性系统理论与方法的一本著作。它既有作者对过去水文系统非线性系统识别理论研究的成果总结,也有作者最近几年开展的环境变化下流域水文循环复杂性探索以及分布式流域水循环模拟与应用的成果。全书分为七章,分别从水文循环及水文系统的基本概念、水文非线性系统识别原理、水文非线性系统描述的泛函模型方法、集总式的水文非线性概念性模型途径,以及流域分布式水循环系统多个层面,阐述水文非线性系统模拟、水文预报、水量转化分析、水资源评价和水文生态系统的特征及应用实例。
本书可供地球科学、水利工程、农学、环境类的水文水资源及其相关专业研究者、教师、研究生和大学高年级学生阅读和参考。
Resumo:
比较细胞遗传学研究发现物种的形成过程往往伴随着核型结构的变化,各种鹿属动物染色体的巨大差异正是很好的例证'赤魔的染色体被证明是由具有端着丝粒的祖先染色体经过多次的串联融合进化而来的。根据祖先染色体的形态和连接方式,可以将染色体串联融合主要分为三类:着丝粒一着丝粒融合,着丝粒一端粒融合和端粒一端粒融合。经典细胞遗传学,比较染色体涂色,卫星DNA序列和部分融合位点序列比较研究都支持串联融合假说。但串联融合的类型和分子机制迄今没有完全弄清楚。本论文旨在对魔属动物的串联融合类型和分子机制进行研究,分为两个部分:一、通过比较染色体涂色的方法,建立小鹿一林察一大额牛的比较染色体图谱,结合以前发表的结果来阐明鹿科(小魔)与牛科(大额牛),寮科(林磨)之间的核型关系;二、建立赤鹿的全基因组BAc文库,通过克隆定位的方法确立在赤魔的染色体进化过程中所发生的串联融合类型,并对其机制进行探讨。主要结果如下:利用小鹿的染色体特异探针与林寮,大额牛的染色体进行杂交,首次建立了小鹿一大额牛,小魔一林察的核型对比关系。结果显示小鹿的1-5、11号染色体均与林集和大额牛的多段染色体同源。结合高分辨的G带比较,发现小魔1-5和11号染色体上的与林爵和大额牛对应的所有同源片断在小鹿染色体上呈着丝粒一端粒连接排列。从而进一步证明小鹿的1-5和11号染色体是由2n=70的祖先核型通过染色体的着丝粒一端粒串联融合方式进化而来的。建立了我国第一个赤魔全基因组BAC文库,该文库由124800个克隆组成。大部分插入片段的大小在100-145kb之间,片段的平均大小为12<0kb。克隆定位显示克隆的分布与小鹿染色体大小成正比关系,说明整个文库没有染色体的偏倚,文库为整个基因组的6倍,覆盖率几乎为100%。通过赤鹿BAC克隆在小魔和赤鹿染色体上的精确定位,使我们得以准确判断小鹿染色体在赤鹿染色体同源片段上的连接方式,并确定串联融合的类型。结果进一步支持赤鹿的核型是由一个2n=70祖先核型通过着丝粒一端粒的融合方式进化而来的。
Resumo:
A capillary zone electrophoresis with end-column electrochemiluminescence (ECL) detector was described for the determination of benzhexol hydrochloride. The detection was based on the tris(2,2'-bypyridine)ruthenium(II) [Ru(bpy)(3)(2+)] ECL reaction with the analyte. Electrophoresis was performed using a 25 mum i.d. uncoated capillary. 10 mM sodium phosphate buffer (pH=8.0) was used as the running buffer. The solution in the detection cell was 80 mM sodium phosphate (pH=8.0) and 5 mM)21 Ru(bpy)(3)(2+). A linear calibration curve of three-orders of magnitude was obtained (with a correlation coefficient of > 0.999) from 1.0X10(-8) to 1.0X10(-5) M and the limit of detection was 6.7 X 10(-9) M (S/N= 3). This just provides an easy and sensitive method to determine the active ingredient in pharmaceutical formulations.
Resumo:
AAO模板具有高度有序的纳米孔阵列 ,其孔径在 5~ 2 0 0nm范围内可调控 ,已被用于制备金属、非金属、半导体、导电高分子等纳米粒子阵列、纳米电缆、纳米“三明治”结构、纳米管和纳米线等纳米材料。这些纳米材料在光、磁、电和催化等方面不仅具有重要的理论研究价值而且具有潜在的应用前景。本文综述了AAO模板纳米阵列孔的有序化、孔径的调控、组装技巧和合成的纳米材料的性质及应用
Resumo:
By doping a fluorescent dye in the emissive layer, we realized high efficient red organic light-emitting diodes (OLEDs) based on a europium complex. The OLEDs realized by this method showed pure red emission at 612 nm with a full width at half maximum Of 3 nm. The Commission International de L'Eclairage Coordination keeps approximately the same as the emission of pure Eu3+. The maximum brightness and EL efficiency reached 2450 cd/m(2) at 20 V and 9.0 cd/A (6.0 lm/w) at a current density of 0.012 mA/cm(2), respectively. At the brightness of 100 cd/m(2), the current efficiency reached 4.4 cd/A.
Resumo:
The stability constants and species distributions of complexes of two lanthanide ions, Eu (III) and Tb(III), with a macrocyclic ligand, 3,6, 9, 17 20, 23-hexaazo-29, 30-dihydroxy-13, 27-dimethyl-tricylco-[23,3,1,1(11,15)] triaconta-1 (28) 11,13,15 (30), 25 26-hexane (BDBPH), in 1: 1 and 2: 1 system, were determined potentiometrically in 50% ethanol solution, at 35.0 degrees C and I = 0.100 mol/L (KCl). The two metal ions could form deprotonated mono- or dinuclear complexes with BDBPH with high stability after the three protons of the ligand completely neutralized. At higher pH values, Eu(M) could not form hydroxo complexes with BDBPH, while Tb(III) could form hydroxo complexes in the types of M2L(OH) M2L(OH)(2) and M2L (OH)(2). The kinetic study on the hydrolysis reaction of his (4-nitrophenyl) phosphate (BNPP) catalyzed by Tb-BDBPH system (2:1) was carried out in aqueous solution (pH 7.0 similar to 10.0) at 35 degrees C with I = 0.1000 mol/L (KCl). The second-order rate constant k(BNPP) (2.3 x 10(-3) (mol/L)(-1)center dot s(-1)) was determined. The dinuclear monohydroxo species, L-Tb-2-OH, is kinetically active species.
Resumo:
The IR spectrum and B-11 and Al-27 MAS NMR spectra of Al18B4O33 are presented and discussed in relation to the possible existence of boron atoms substituting for aluminum atoms. The IR spectrum shows that the strong vibrations of the BO3 groups are present in the 1 500 similar to1 200 cm(-1) region, and very weak bands of BO4 units art present in the region from 1 000 to 1 100 cm(-1). B-11 MAS NMR spectrum indicates that the strong signal for BOB units appears in the region from delta +5 to delta +20, and the very weak signal for BO4 units is at about delta -1, while Al-27 MAS NMR spectrum shows five peaks at about delta +62, +42.1, +14, -4.7 and -6.4, originating from AlO4, AlO4, AlO5, AlO6 and AlO6, respectively, These results reveal that there are minor BO4 units in Al18B4O33, indicating that a small amount of B atoms substitute for Al atoms in the 4-fold coordination.
Resumo:
The A(m) index and molecular connectivity index were used for studying the photoionization sensitivity of some organic compounds in gas chromatography. The analysis of structure-property relationship between the photoionization sensitivity of the compounds and the A(m) indices or molecular connectivity indices has been carried out. The genetic algorighm was used to build the correlation model in this field. The results demonstrate that the property of compounds can be described by both A(m) indices and molecular connectivity indices, and the mathematical model obtained by the genetic algorithm was better than that by multivariate regression analysis.
Resumo:
把A_m拓扑指数与分子连接性指数用于有机化合物气相色谱分析的光离子化灵敏度的结构.性质相关性研究中,并将遗传算法(GA)引用于本研究中建模,与相应体系的光离子化灵敏度进行相关分析时发现,A_m指数,分子连接性指数均能较好地反映化合物的结构特征,但各有特点,GA算法所得结果优于多元回归分析。
Resumo:
Multilayer films were fabricated by layer-by-layer electrostatic deposition techniques between poly(diallyIdimethylammonium chloride) (PDDA) and calf thymus DNA (CT DNA) on glassy carbon and quartz substrates. Electrochemical impedance spectroscopy (EIS), Fourier transform infrared (FTIR) spectroscopy and UV-vis spectroscopy demonstrated the uniform assembly of PDDA/DNA multilayer films, and X-ray photoelectron spectroscopy confirmed the elemental composition of the films. Moreover, the interaction of DNA in PDDA/DNA films with methyl green was investigated by UV-vis spectroscopy and circular dichroism (CD). (C) 2001 Elsevier Science B.V. All rights reserved.
Resumo:
以苯乙烯 -马来酸酐无规共聚物 ( SMA)为有机组分 ,以正硅酸乙酯 ( TEOS)为无机组分 ,利用 sol-gel方法制得纳米杂化材料 .以此为载体合成了载体化钛系催化剂 ,进行了苯乙烯聚合的研究 .聚合结果表明在50℃左右聚苯乙烯的间规度达到最大 ;随着反应温度的提高 ,分子量出现了下降现象 ,但反应活性提高 ,在70℃时 ,可达最高 1 .4 9× 1 0 6 g/( mol·h) ;并且分子量分布与文献结果相比也较宽 .
Resumo:
(A) novel chemiluminescence (CL) system was evaluated for the determination of hydrogen peroxide, glucose and ascorbic acid based on hydrogen peroxide, which has a catalytic-cooxidative effect on the oxidation of luminol by KIO4. Hydrogen peroxide can be directly determined by luminol-KIO4 -H2O2 CL system. The detection limit was 3.0 x 10(-8) mol l(-1) and the calibration graph was linear over the range of 2.0 x 10(-7)-6.0 x 10(-4) mol l(-1). The relative standard deviation of H2O2 was 1.1% for 2.0 x 10(-6) mol l(-1) (N = 11). Glucose was indirectly determined through measuring the H2O2 generated by the oxidation of glucose in the presence of glucose oxidase at pH 7.6. The present method provides a source for H2O2, which, in turn, coupled with the luminol-KIO4-H2O2 CL reaction system. The CL was linearly correlated with glucose concentration of 0.6-110 mu g ml(-1). The relative standard deviation was 2.1% for 10 mu g ml(-1) (N = 11). Detection limit of glucose was 0.08 mu g ml(-1). Ascorbic acid was also indirectly determined by the suppression of luminol-KIO4-H2O2 CL system. The calibration curve was linear over the range of 1.0 x 10(-7)-1.0 x 10(-5) mol l(-1) of ascorbic acid. The relative standard deviation was 1.0% for 8.0 x 10(-7) mol l(-1) (N = 11). Detection limit of ascorbic acid was 6.0 x 10(=8) mol l(-1). These proposed methods have been applied to determine glucose, ascorbic acid in tablets and injection. (C) 1999 Elsevier Science B.V. All rights reserved.
Resumo:
Electrochemical redox behavior of noradrenaline in alkaline solution on a glassy carbon electrode has been investigated by in situ UV-vis and CD spectroelectrochemistry by using a long optical path thin-layer cell. The experimental data were processed by using a double logarithmic method of analysis together with nonlinear regression which confirmed that the first step in both the oxidation of noradrenaline and reduction of noradrenochrome is a two-electron irreversible process governed by an EE mechanism. The kinetic parameters of the electrode reactions, i.e., charge transfer coefficient and the number of electrons transferred, alpha(1)n(1) = 0.11 and alpha(2)n(2) = 0.23, formal potentials modified with kinetics, E-1(0') = 0.65 (+/- 0.01) V and E-2(0') = 0.72V and standard rate cnstants, k(1)(0) = 7.0(+/-0.5)x10(-5) cm s(-1), for the first and second steps in the oxidation process of noradrenaline, and similarly, alpha(1)n(1) = 0.33, alpha(2)n(2) = 0.58, E-1(0') = 0.37(+/-0.01) V, E-0' = -0.25 (+/-0.01) V and k(1)(0) approximate to k(2)(0) = 1.06 (+/-0.05)x10(-4) cm s(-1) for the first and second steps in the reduction process of noradrenochrome were also determined.