Reactions of C-60 with R(3)SnH: A new synthetic route to C-60(RH)(n) and the property of C-60 to catalyze radical reactions

A new method for the preparation of polyalkyl and polyarenefullerene derivatives C-60(RH)(n)(R=Bu,n=1-3; R=Ph,n=1-10) by the reaction of C-60 with organotin hydride in toluene is described. Another series of products of stannanes R(a)Sn(b)H(c) (R=Bu, a=3-8, b=1-4, c=0-3 R=Ph, a=3-11, b=1-5, c=0-4) were also obtained, which shows that C-60 can catalyze polymerization of organic-tin. These products were determined by mass and infrared spectrometry. And the possible reaction mechanisms are discussed.

烟酸及其同分异构体对细胞色素c直接电化学反应的影响

细胞色素c作为生物体内的一种电子载本,近年来它的电化学行为引起了电化学家们的极大兴趣.本文比较了与生物体内细胞色素c电子传递过程相关的烟酸及其同分异构体对细胞色素c电化学反应的促进作用,Hill研究组曾利用短时间吸附法考察过4-吡啶羧酸对细胞色素c电化学反应的影响,未观察到该化合物的促进作用.但我们发现金电极在4-吡啶羧酸溶液中经过长达1h以上浸泡后就可以观察到它的促进作用,而且

CRYSTAL-STRUCTURE OF [YB (NO3)3 (PHEN) (H2O)]CENTER-DOT(12-CROWN-4)

The title complex was prepared by reacting Yb(NO3)3 (12-crown-4) with 1, 10-phenanthiroline (hereafter phen) in acetone. It crystallized in the triclinic space group P1BAR with a = 10.095(5), b = 17.415(4), c = 8.710(2) angstrom; alpha = 92.45(2), beta = 115.83(3), gamma = 74.08(3)degrees and D(c), = 1.85 g cm-3; Z = 2. The metal ion in this complex is nine-coordinated to three bidentate nitrate ions, two nitrogen atoms of a phen and a water molecule. The crown ligand is hydrogen bonded to the coordination water molecule. The symmetry change of the crown ether is also discussed.

细胞色素C在单糖修饰金电极上的直接电化学

Hill等发现在4,4′-联吡啶存在时,细胞色素C在金电极上能进行准可逆的电化学反应。在研究细胞色素C的直接电化学过程中,人们又发现一些生物小分子如氨基酸、嘌呤等对细胞色素C的电化学反应有促进作用,但迄今未见有关糖类分子对细胞色素C电化学反应促进作用研究的报道。本文研究了5种单糖对细胞色素C电化学反应的促进作用。

细胞色素c在咔唑修饰的金电极上的直接电化学

在生物体内,细胞色素c是一种电子载体,它能进行可逆的氧化还原反应,但在金属电极上的电化学反应却不可逆。1977年,Hill研究组发现,在4,4′-联吡啶存在时,细胞色素c在金电极上能进行准可逆的电化学反应。4,4′-联吡啶在细胞色素c电化学反应的过程中不起氧化还原反应而被称为促进剂。Hill等对50多种有机化合物的促进作用进行评价后提出,能加速细胞色素c电化学反应速率的促进剂分子至少应具有两个功能团。表面增强拉曼光

Low temperature X-ray crystallographic structures of two lamotrigine analogues: (I) 2-methyl,3-amino, 5-imino-6-(2,3-dichlorophenyl)-1,2,4-triazine water solvate and (II) 2-methyl,3,5-diamino-6-(2,3-dichlorophenyl)-1,2,4-triazine isethionate, hemi-hydrate

The X-ray crystal structures of two lamotrigine derivatives (I) 2-methyl, 3-amino, 5-imino-6-(2, 3-dichlorophenyl)-1,2,4-triazine, C10H9Cl2N5, as the hemi hydrate and (II) 2-methyl,3,5-diamino-6-(2,3-dichlorophenyl)-1,2,4-triazine, C10H10Cl2N5, as the isethionate-water solvate, have been carried out at liquid nitrogen temperature. A detailed comparison of the two structures is given. Both are monoclinic and centrosymmetric, with (I) in space group C2/c, and (II) in space group P2(1)/n. For (I) the unit cell dimensions are a = 19.5466(10), b = 7.5483(4), c = 15.7861(8) angstrom, beta = 91.458(3)degrees, volume = 2328.4(2) angstrom(3), Z = 8, density = 1.590 Mg/m(3); for (II). For (II) the unit cell dimensions are a = 6.0566(2), b = 11.0084(4) c = 23.9973(9) angstrom, beta = 92.587(3)degrees, volume = 1598.35(10) angstrom(3), Z = 4, density = 1.597 Mg/m(3). For (I) final R indices [I > 2sigma(I)] are R1 = 0.0356, wR2 = 0.0782 and R indices (all data) are R1 = 0.0424, wR2 = 0.0817. For (II) final R indices [I > 2sigma(I)] are R1 = 0.0380, wR2 = 0.0871 and R indices (all data) R1 = 0.0558, wR2 = 0.0949. Both structures have a molecule of water of crystallization and (II) also includes a solvated CH3SO3. Comparisons are made between the two structures. Structure (I) is very unusual in having a = NH group at position C5' on the triazine ring. No other examples of this particular substitution, which is usually -NH2, have been reported.

Entropy change and magnetocaloric effect in Gd5(SixGe1-x)4

Isothermal magnetization curves up to 23 T have been measured in Gd5Si1.8Ge2.2. We show that the values of the entropy change at the first-order magnetostructural transition, obtained from the Clausius-Clapeyron equation and the Maxwell relation, are coincident, provided the Maxwell relation is evaluated only within the transition region and the maximum applied field is high enough to complete the transition. These values are also in agreement with the entropy change obtained from differential scanning calorimetry. We also show that a simple phenomenological model based on the temperature and field dependence of the magnetization accounts for these results.

C??mo realizar una revisi??n sistem??tica y un meta-an??lisis

Resumen tomado de la publicaci??n

El modelamiento en vídeo de las categorías 4 y 6 del análisis de interacción ampliado de E. Amidon, P. Amidon y B. Rosenshine.

Probar los efectos de la grabación de modelos en un laboratorio de CCTV (circuito cerrado de televisión) y en un aula real mediante CPTV (circuito portátil de televisión), así como de los modelos simbólicos (escrito) frente a los perceptuales. Para ello plantea 2 hipótesis a contrastar: 1) Los modelos de las categorías 4 y 6 del AIA de Amidon, Amidon y Rosenshine realizados en un laboratorio de CCTV dan unos resultados, en cuanto al grado de identificación y discriminación de los mismos conseguidos por alumnos profesores, superiores a los modelos de las mismas categorías realizados en un aula real por medio de CPTV, y ambos, CCTV y CPTV, son superiores a los modelos escritos. 2) La actitud de los profesores ante los modelos de esas categorías realizadas en un laboratorio por medio de CCTV es más positiva que su actitud ante los modelos de estas categorías realizados en un aula real por medio de CPTV. 117 alumnos profesores inscritos en los cursos del CAP, asignados aleatoriamente a los 6 grupos experimentales. Diseño experimental 2 x 3. Dos categorías: la número 4 en que el profesor formula preguntas, con 3 subcategorías, preguntas de hecho (h), convergentes (c) y divergentes (d) y la número 6 en que el profesor da direcciones con 2 subcategorías, direcciones cognitivas (c) y disciplinarias (d); 3 condiciones: laboratorio (l), aula (a) y escrito (e); en total 6 grupos experimentales. Variables dependientes: 1) El grado de identificación y discriminación de las subcategorías y, 2) Las actitudes de los alumnos profesores ante los modelos. Hojas-registro de subcategorías y escala de actitudes. Prueba de rango de Duncan. Medias y porcentajes. Se encontraron diferencias significativas entre el grupo 'l' y 'a' en la categoría número 4, también entre el grupo 'l' y las medias de 'e y a' de la subcategoría 4 'h', sin embargo, no aparecen diferencias significativas entre los 3 grupos para la subcategoría 4 'c'. En la categoría número 6 ha sido significativa la diferencia entre las medias de los grupos 'e y l', no siendo así entre los grupos 'l y e' y 'e y a'. En la subcategoría 6 'a' ha sido significativa la diferencia entre los grupos 'l' y los otros grupos. La diferencia entre los grupos 'l' y 'a' ha sido significativa, no siéndolo entre los grupos 'l y e' y 'e y a' dentro de la subcategoría 6 'd'. De los resultados anteriores se confirma la segunda pero no la primera hipótesis de la investigación, es decir, los profesores alumnos muestran una actitud más positiva hacia los modelos realizados por CCTV, mientras que los 3 modelos (l, a, e) son igual de eficaces para la identificación y discriminación de categorías.

Synthesis and photoreactivity of aryl substituted 4,5-dithienyl[1,3]dithiol-2-ones

UV irradiation of hitherto unknown 4,5-bis-benzol[b]thiophen-3-yl-[1,3]dithiol-2-one gave 3-(3-benzo[b]thienyl)-thieno[3,4-c]benzo[ e][1,2]dithine by loss of carbon monoxide and rearrangement, whereas 4,5-bis-(2-bromo-phenyl)-[1,3]dithiol-2-one gave a polymeric material containing S-S bridges. The Structures of both photoproducts were demonstrated on the basis of chemical behaviour and/or X-ray diffraction. (C) 2009 Elsevier Ltd. All rights reserved.

The C(K, X) spaces for compact metric spaces K and X with a uniformly convex maximal factor

In this paper, we prove that if a Banach space X contains some uniformly convex subspace in certain geometric position, then the C(K, X) spaces of all X-valued continuous functions defined on the compact metric spaces K have exactly the same isomorphism classes that the C(K) spaces. This provides a vector-valued extension of classical results of Bessaga and Pelczynski (1960) [2] and Milutin (1966) [13] on the isomorphic classification of the separable C(K) spaces. As a consequence, we show that if 1 < p < q < infinity then for every infinite countable compact metric spaces K(1), K(2), K(3) and K(4) are equivalent: (a) C(K(1), l(p)) circle plus C(K(2), l(q)) is isomorphic to C(K(3), l(p)) circle plus (K(4), l(q)). (b) C(K(1)) is isomorphic to C(K(3)) and C(K(2)) is isomorphic to C(K(4)). (C) 2011 Elsevier Inc. All rights reserved.

Electro-precipitation of Fe(3)O(4) nanoparticles in ethanol

The preparation of superparamagnetic magnetite (Fe(3)O(4)) nanoparticles by electro-precipitation in ethanol is proposed. Particle average size can be set from 4.4 to 9 nm with a standard deviation around 20%. Combination of wide-angle X-ray scattering (WAXS), Electron energy loss spectroscopy (EELS) and Mossbauer spectroscopy characterizations clearly identifies the particles as magnetite single-crystals (Fe(3)O(4)). (C) 2008 Elsevier B.V. All rights reserved.

Isolamento de Candida spp em leite proveniente de bovinos com mastite em 4 estados brasileiros

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)