945 resultados para EXAFS XANES Cu(I) Cu(II) soluzioni


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Chicken egg yolk biotin-binding protein-I (BBP-I) has been purified to homogeneity along with the tetrameric BBP-II by a common protocol. The purification includes delipidation of egg yolk by butanol extraction, DEAE-Sephacel chromatography, treatment with guanidinium chloride and biotin-aminohexyl-Sepharose affinity chromatography. The identity of purified BBP-I was ascertained by its physicochemical properties as well as by its immunological cross-reactivity and precursor-product relationship with BBP-II.

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Effects of fluctuations in habitat temperature (18-30 degrees) on mitochondrial respiratory behavior and oxidative metabolic responses in the euryhaline ectotherm Scylla serrate are not fully understood. In the present study, effects of different temperatures ranging from 12 to 40 degrees C on glutamate and succinate mediated mitochondrial respiration, respiratory control ratio (RCR), ATP generation rate, ratio for the utilization of phosphate molecules per atomic oxygen consumption (P/O), levels of lipid peroxidation and H2O2 in isolated gill mitochondria of S. serrata are reported. The pattern of variation in the studied parameters was similar for the two substrates at different temperatures. The values recorded for RCR ( >= 3) and P/O ratio (1.4-2.7) at the temperature range of 15-25 degrees C were within the normal range reported for other animals (3-10 for RCR and 1.5-3 for P/O). Values for P/O ratio, ATP generation rate and RCR were highest at 18 degrees C when compared to the other assay temperatures. However, at low and high extreme temperatures, i.e. at 12 and 40 degrees C, states III and IV respiration rates were not clearly distinguishable from each other indicating that mitochondria were completely uncoupled. Positive correlations were noticed between temperature and the levels of both lipid peroxidation and H2O2. It is inferred that fluctuations on either side of ambient habitat temperature may adversely influence mitochondria respiration and oxidative metabolism in S. serrata. The results provide baseline data to understand the impacts of acute changes in temperature on ectotherms inhabiting estuarine or marine environments. (C) 2014 Elsevier Ltd. All rights reserved.

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El presente trabajo es el resultado de un diagnostico realizado en las regiones I y II de Nicaragua. El objetivo del estudio fue conocer el rol que juegan las mujeres y los niños en las prácticas de control de plagas y en particular en el manejo de los plaguicidas. Para obtener la información del estudio se realizó una encuesta dirigida a mujeres y niños en 18 comunidades de los departamentos de Estelí, Nueva Segovia, León y Chinandega. En el estudio resultó que la participación de la mujer y los menores es alta, los resultados muestran que el 96% de la mujer y el 85% de los niños tienen participación en todas las fases agrícolas. Las prácticas de manejo integrado de plagas implementadas por las productoras son mayoritariamente recuentos de plagas, rotación de cultivos, cultivos en asocio y variedades mejoradas. Generalmente la aplicación de plaguicidas, lavado de la ropa contaminada, preparación de la mezcla y acarreo del plaguicida al lugar de aplicación. En el manejo y exposición al riesgo de los plaguicidas el 65% de las productoras en la región II contestó que conocían de personas intoxicadas, además identificaron la intoxicación laboral como la más común. En la región I, 42% de las productoras mencionó conocer de personas intoxicadas. Cuatro de los plaguicidas reportados en existencia por las agricultoras son altamente a extremadamente peligrosos, estos plaguicidas son almacenados principalmente dentro de la casa, 15% de las productoras utilizan los envases de plaguicidas para almacenar agua y alimento y el 8% para echar más veneno. Además el 88% de las productoras mencionaron conocer de los efectos adversos de la utilización de los plaguicidas, sobre todo en la salud humana. Finalmente la encuesta indica que las capacitaciones en MIP son dirigidas en su gran mayoría a los hombres y cuando incluyen a las mujeres los lugares y hora escogida para las capacitaciones eran uno los factores que obstaculizaba su participación. La falta de títulos de propiedad, que limita el acceso al crédito para la siembra, fue otro factor limitante para participar en actividades MIP. Las instituciones y los programas radiales educativos, así como la comunicación directa, juegan un papel importante en la transmisión de conocimientos MIP

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PART I

The energy spectrum of heavily-doped molecular crystals was treated in the Green’s function formulation. The mixed crystal Green’s function was obtained by averaging over all possible impurity distributions. The resulting Green’s function, which takes the form of an infinite perturbation expansion, was further approximated by a closed form suitable for numerical calculations. The density-of-states functions and optical spectra for binary mixtures of normal naphthalene and deuterated naphthalene were calculated using the pure crystal density-of-state functions. The results showed that when the trap depth is large, two separate energy bands persist, but when the trap depth is small only a single band exists. Furthermore, in the former case it was found that the intensities of the outer Davydov bands are enhanced whereas the inner bands are weakened. Comparisons with previous theoretical calculations and experimental results are also made.

PART II

The energy states and optical spectra of heavily-doped mixed crystals are investigated. Studies are made for the following binary systems: (1) naphthalene-h8 and d8, (2) naphthalene--h8 and αd4, and (3) naphthalene--h8 and βd1, corresponding to strong, medium and weak perturbations. In addition to ordinary absorption spectra at 4˚K, band-to-band transitions at both 4˚K and 77˚K are also analyzed with emphasis on their relations to cooperative excitation and overall density-of-states functions for mixed crystals. It is found that the theoretical calculations presented in a previous paper agree generally with experiments except for cluster states observed in system (1) at lower guest concentrations. These features are discussed semi-quantitatively. As to the intermolecular interaction parameters, it is found that experimental results compare favorably with calculations based on experimental density-of-states functions but not with those based on octopole interactions or charge-transfer interactions. Previous experimental results of Sheka and the theoretical model of Broude and Rashba are also compared with present investigations.

PART III

The phosphorescence, fluorescence and absorption spectra of pyrazine-h4 and d4 have been obtained at 4˚K in a benzene matrix. For comparison, those of the isotopically mixed crystal pyrazine-h4 in d4 were also taken. All these spectra show extremely sharp and well-resolved lines and reveal detailed vibronic structure.

The analysis of the weak fluorescence spectrum resolves the long-disputed question of whether one or two transitions are involved in the near-ultraviolet absorption of pyrazine. The “mirror-image relationship” between absorption and emission shows that the lowest singlet state is an allowed transition, properly designated as 1B3u1A1g. The forbidden component 1B2g, predicted by both “exciton” and MO theories to be below the allowed component, must lie higher. Its exact location still remains uncertain.

The phosphorescence spectrum when compared with the excitation phosphorescence spectra, indicates that the lowest triplet state is also symmetry allowed, showing a strong 0-0 band and a “mirror-image relationship” between absorption and emission. In accordance with previous work, the triplet state is designated as 3B3u.

The vibronic structure of the phosphorescence spectrum is very complicated. Previous work on the analysis of this spectrum all concluded that a long progression of v6a exists. Under the high resolution attainable in our work, the supposed v6a progression proves to have a composite triplet structure, starting from the second member of the progression. Not only is the v9a hydrogen-bending mode present as shown by the appearance of the C-D bending mode in the d4 spectrum, but a band of 1207 cm-1 in the pyrazine in benzene system and 1231 cm-1 in the mixed crystal system is also observed. This band is assigned as 2v6b and of a1g symmetry. Its anonymously strong intensity in the phosphorescence spectrum is interpreted as due to the Fermi resonance with the 2v6a and v9a band.

To help resolve the present controversy over the crystal phosphorescence spectrum of pyrazine, detailed vibrational analyses of the emission spectra were made. The fluorescence spectrum has essentially the same vibronic structure as the phosphorescence spectrum.

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Esta pesquisa apresenta a obra Memorial do Cristo, de autoria de Dinah Silveira de Queiroz, em seus dois volumes: Eu Venho e Eu, Jesus. Esses dois livros juntos narram uma única história, a autobiografia de Jesus Cristo. Esta tese discute os aspectos lingüísticos e literários, sendo focalizados principalmente o léxico que caracteriza a intertextualidade com a Bíblia, o campo semântico e a estrutura sintático-gramatical. Um capítulo foi dedicado ao estudo de fatos relativos à vida da autora por influenciarem de forma significativa o seu estilo

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Several biochemical responses were measured in silver crucian carp (Carassius auratus gibelio) after exposure to sediments obtained from contaminated Ya-Er Lake, No, 1 pond, and an unpolluted reference site, Honglian Lake. After 1 week of exposure, a significant induction of the phase I biotransformation enzyme (ethoxylresorufin-o-deethylase, EROD) was found (83-fold of control), whereas the phase II biotransformation enzyme (glutathione S-transferase, GST) exhibited a slight, but significant induction (1,4-fold of control) after 4 weeks of exposure. The level of cellular glutathione in the liver was also slightly elevated after 4 weeks of exposure. The delayed response of GST to the contaminants indicates that the phase I and phase II biotransformation enzymes are regulated differently in fish. The results suggest that EROD is a sensitive bioindicator to assess the toxicity of dioxin-contamined sediment in the laboratory, (C) 1998 Academic Press.

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The photoluminescence (PL) of In0.55Al0.45As/Al0.5Ga0.5As self-assembled quantum dots has been measured at 15 and 80 K under hydrostatic pressure. The lateral size of the dots ranges from 7 to 62 nm. The emissions from the dots with 26, 52 and 62 nm size have a blue shift under pressure, indicating that these quantum dots have the normal type-I structure with lowest conduction band at the Gamma -valley. However, the PL peak of dots with 7 nm diameter moves to lower energy with increasing pressure. It is a typical character for the X-related transition. Then these small dots have a type-II structure with the X-valley as the lowest conduction level. An envelope-function calculation confirms that the Gamma -like exciton transition energy will rise above the X-like transition energy in the In0.55Al0.45As/Al0.5Ga0.5As structure if the dot size is small enough.

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We investigate the electronic structures of the inhomogeneous quantum dots within the framework of the effective mass theory. The results show that the energies of electron and hole states depend sensitively on the relative magnitude 77 of the core radius to the capped quantum dot radius. The spatial distribution of the electrons and holes vary significantly when the ratio eta changes. A quantum-confinement-driven type-II-type-I transition is found in GaAs/AlxGa1-xAs-capped quantum dot structures. The phase diagram is obtained for different capped quantum dot radii. The ground-state exciton binding energy shows a highly nonlinear dependence on the innner structures of inhomogeneous quantum dots, which originates from the redistribution of the electron and hole wave functions.

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用蓖麻油与TDI反应生成端异氰酸酯基预聚物,再与HEA反应,生成端乙烯基预聚物,以不同比例的MMA与端乙烯基预聚物共聚交联,得到一组组成和交联密度各不相同的ABCP样品;为了分别观察组成和交联密度对材料性能的影响,在交联共聚过程中,以二乙烯基苯作交联点调节剂 ,得到固定组成,交联密度变化和固定交联密度组成变化的两组样品;此外,在固化过程中加入不同含量的丙烯酸(<10%),得到另一组样品,以观察氢键对该体系的影响。反应过程中用化学分析、NMR、IR及平衡溶胀等方法测定反应程度、分子量及交联网的交联密度;同时用动态粘弹谱仪和介电损耗仪测定样品的动态力学性能,转变与松弛及相容性;用材料试验机测试样品的力学性能;通过透射电子显微镜观察材料的形态结构。结果表明:copu/PMMA ABCP是个半相容体系,随硬段含量的增加和交联密度的减小相容性变差。形态结构呈不规则形状,相区尺寸由几A变至几百A,材料的力学性能和阻尼性能明显优子构成它们的均聚物。材料的阻尼值主要受交联密度的影响,玻璃化转变温度则主要受组成控制。氢键对该体系的形态结构有明显影响,丙烯酸含量为7.5%时相容性最差,5%和10%时最好。以双阳昌10号井原油为研究对象选用EVA作原料,以马来酸酐接枝改性,合成ET-6降凝剂。采取在热处理中加入降凝剂的综合处理方法,考察了降凝剂合成的最佳反应条件和降凝剂用量及热处理温度对原油结晶状态及流动性的影响。结果表明,热处理中加入ET-6降凝剂可使蜡的结晶形态发生明显变化,降凝剂用量仅100-500 ppm即可使双阳原油的凝固点由原来的30-31 ℃降至7-9 ℃,原油的低温流动性大为改观。

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The photoluminescence (PL) of In0.55Al0.45As/Al0.5Ga0.5As self-assembled quantum dots has been measured at 15 and 80 K under hydrostatic pressure. The lateral size of the dots ranges from 7 to 62 nm. The emissions from the dots with 26, 52 and 62 nm size have a blue shift under pressure, indicating that these quantum dots have the normal type-I structure with lowest conduction band at the Gamma -valley. However, the PL peak of dots with 7 nm diameter moves to lower energy with increasing pressure. It is a typical character for the X-related transition. Then these small dots have a type-II structure with the X-valley as the lowest conduction level. An envelope-function calculation confirms that the Gamma -like exciton transition energy will rise above the X-like transition energy in the In0.55Al0.45As/Al0.5Ga0.5As structure if the dot size is small enough.

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本文利用单向SDS-PAGE方法对十八株Frankia菌的全细胞可溶性蛋白进行了图谱分析。Frankia菌蛋白图谱不受菌令的影响。不同交叉接种组的Frankia菌具有不同的蛋白图谱,同一交叉接种组内的菌株也有所羞。十八株菌分为三大类七个亚类,第I类包括赤场、杨梅香蕨木和美洲茶内生菌;第II类包括木麻黄内生菌,第III类包括胡颓子和沙棘内生菌。利用同功酶图谱的差异性对Frankia菌进行分类识别是一种非常有效的方法,不同的Frankia菌株具有不同的同功酶(过氧化物酶和酯酶)图谱。根据图谱之间的相似性,可以将二十株Frankia菌分成三组;即赤杨组,木麻黄组和胡颓子组,这与其它分类结果基本符合,只是细枝木麻黄菌株CcO1的过氧化物酶图谱与其它菌株完全不同。从同种根瘤中分离的内生菌具有不同的同功酶图谱,进一步证实了遗传结构不完全相同的菌株可以同时共生于同种根瘤内,同时根据二种同功酶的电泳分布率,说明了Frankia菌株遗传信息的广泛分布性。