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11.
Sánchez P Gálvez N Colacio E Miñones E Domínguez-Vera JM 《Dalton transactions (Cambridge, England : 2003)》2005,(4):811-813
It has been traditionally considered that catechols release iron from ferritin by reduction to iron(II), which diffuses through the ferritin channels into the intracellular milieu where it participates in the Fenton reaction, producing highly toxic hydroxyl radicals. However, in the present work we have proved that the mechanism of the release of iron from ferritin by catechol does not take place by iron(II) reduction but by direct iron(III) chelation and therefore without iron(II) production. A possible extension of these findings to other catechols is discussed on the basis of the stability with respect to the internal redox reaction of the iron(III)-catechol complexes. 相似文献
12.
Francisca Barrios Juan M. Salas M. Purificación Sánchez Miguel Quirós René Faure 《Journal of chemical crystallography》1999,29(9):1009-1013
The complex [Ni(XsH–1)2(H2O)4]·6H2O (XsH–1: xanthosinate) was isolated from the reaction of nickel carbonate with xanthosine in aqueous solution. The octahedral coordination is supported by the reflectance measurements. Single-crystal X-ray diffraction studies show that the crystals belong to the triclinic P1 space group, with a = 7.152(1), b = 8.830(1),c = 13.783(1) Å, = 82.024(1)°, = 86.155(1)°, = 70.900(1)°, and D = 1.643 mg/m3, forZ = 1. Nickel is six coordinate with four water molecules, and two N7 atoms from xanthosinato ligands. A complicated hydrogen-bonding network is present, all possible donors taking part in it. 相似文献
13.
Guldi DM Gouloumis A Vázquez P Torres T 《Chemical communications (Cambridge, England)》2002,(18):2056-2057
Fluorescence and transient absorption measurements show that in strongly coupled ZnPc-C60 and H2Pc-C60 dyads charge-separated states are formed; large -delta GCR degree and small lambda assist in stabilising ZnPc(.+)-C60.-/H2Pc(.+)-C60.-. 相似文献
14.
Santiago-Rivas S Moreda-Piñeiro A Bermejo-Barrera P Moreda-Piñeiro J Alonso-Rodríguez E Muniategui-Lorenzo S López-Mahía P Prada-Rodríguez D 《Analytica chimica acta》2007,603(1):36-43
The possibilities of pressurized liquid extraction (PLE) have been novelty tested to assist the cytosol preparation from wet mussel soft tissue before the determination of metals bound to metallothionein-like proteins (MLPs). Results obtained after PLE were compared with those obtained after a classical blending procedure for mussel cytosolic preparation. Isoforms MLP-1 (retention time of 4.1 min) and MLP-2 (retention time of 7.4 min) were separated by anion exchange high-performance liquid chromatography (HPLC) and the concentrations of Ba, Cu, Mn, Sr and Zn bound to MLP isoforms were directly measured by inductively coupled plasma-atomic emission spectrometry (ICP-OES) as a multi-element detector. The optimized PLE-assisted mussel cytosol preparation has consisted of one extraction cycle at room temperature and 1500 psi for 2 min. Since separation between the solid mussel residue and the extract (cytosol) is performed by the PLE system, the cytosol preparation method is faster than conventional cytosol preparation methods by cutting/blending using Ultraturrax or Stomacher devices. 相似文献
15.
Quintana JB Rodil R López-Mahía P Muniategui-Lorenzo S Prada-Rodríguez D 《Analytical and bioanalytical chemistry》2007,388(5-6):1283-1293
A selective analytical method for the determination of nine organophosphate triesters and triphenylphosphine oxide (TPPO)
in outdoor particulate matter is presented. It involves a fully automated pressurised liquid extraction (PLE) step, integrating
an alumina clean-up process, and subsequent determination by large-volume injection gas chromatography–positive chemical ionisation–tandem
mass spectrometry (LVI-GC–PCI–MS/MS). The extraction variables (solvent, amount of adsorbent, temperature, time and number
of cycles) were optimised using a multicriteria strategy which implements a desirability function that maximises both extraction
and clean-up efficiencies while searching for the best-compromise PLE conditions. The final method affords quantification
limits of between 0.01 and 0.3 μg g−1 and recoveries of >80%, with the exceptions of the most polar analytes, TCEP and TPPO (~65%) for both urban dust and PM10
samples. Moreover, the method permitted the levels of these compounds in dust deposited outdoors (between LOD and 0.5 μg g−1 for TEHP) and PM10 samples (between LOD and 2.4 μg m−3 for TiBP) to be measured and reported for the first time.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
16.
Carlos LD Ferreira RA de Zea Bermudez V Julián-López B Escribano P 《Chemical Society reviews》2011,40(2):536-549
Research on organic-inorganic hybrid materials containing trivalent lanthanide ions (Ln(3+)) is a very active field that has rapidly shifted in the last couple of years to the development of eco-friendly, versatile and multifunctional systems, stimulated by the challenging requirements of technological applications spanning domains as diverse as optics, environment, energy, and biomedicine. This tutorial review offers a general overview of the myriad of advanced Ln(3+)-based organic-inorganic hybrid materials recently synthesised, which may be viewed as a major innovation in areas of phosphors, lighting, integrated optics and optical telecommunications, solar cells, and biomedicine. 相似文献
17.
Enes RF Cid JJ Hausmann A Trukhina O Gouloumis A Vázquez P Cavaleiro JA Tomé AC Guldi DM Torres T 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(6):1727-1736
The synthesis and photophysical properties of several fullerene-phthalocyanine-porphyrin triads (1-3) and pentads (4-6) are described. The three photoactive moieties were covalently connected in an one-step synthesis through 1,3-dipolar cycloaddition to C(60) of the corresponding azomethine ylides generated in situ by condensation reaction of a substituted N-porphyrinylmethylglycine derivative and an appropriated formyl phthalocyanine or a diformyl phthalocyanine derivative, respectively. ZnP-C(60)-ZnPc (3), (ZnP)(2)-ZnPc-(C(60))(2) (6), and (H(2)P)(2)-ZnPc-(C(60))(2) (5) give rise upon excitation of their ZnP or H(2)P components to a sequence of energy and charge-transfer reactions with, however, fundamentally different outcomes. With (ZnP)(2)-ZnPc-(C(60))(2) (6) the major pathway is an highly exothermic charge transfer to afford (ZnP)(ZnP(.+))-ZnPc-(C(60)(.-))(C(60)). The lower singlet excited state energy of H(2)P (i.e., ca. 0.2 eV) and likewise its more anodic oxidation (i.e., ca. 0.2 V) renders the direct charge transfer in (H(2)P)(2)-ZnPc-(C(60))(2) (5) not competitive. Instead, a transduction of singlet excited state energy prevails to form the ZnPc singlet excited state. This triggers then an intramolecular charge transfer reaction to form exclusively (H(2)P)(2)-ZnPc(.+)-(C(60)(.-))(C(60)). A similar sequence is found for ZnP-C(60)-ZnPc (3). 相似文献
18.
M. Purificación López López Emilio Villanueva Nóvoa 《Applied Categorical Structures》2013,21(3):237-247
If $\mathcal{C}$ is a strict braided monoidal category in which the idempotent morphisms have a canonical split, we find conditions under which the antipode of a Hopf (co)quasigroup is an isomorphism. We also prove that the object of (co)invariants of a finite Hopf (co)quasigroup in $\mathcal{C}$ is an invertible object. 相似文献
19.
Beatriz Julián‐López Dr. Mónica Martos Dr. Natalia Ulldemolins José A. Odriozola Prof. Eloisa Cordoncillo Dr. Purificación Escribano Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(45):12426-12434
An easy solvothermal route has been developed to synthesize the first mesoporous Er2O3–TiO2 mixed oxide spherical particles composed of crystalline nanoplatelets, with high surface area and narrow pore size distribution. This synthetic strategy allows the preparation of materials at low temperature with interesting textural properties without the use of surfactants, as well as the control of particle size and shape. TEM and Raman analysis confirm the formation of nanocrystalline Er2O3–TiO2 mixed oxide. Mesoscopic ordered porosity is reached through the thermal decomposition of organic moieties during the synthetic process, thus leading to a template‐free methodology that can be extended to other nanostructured materials. High specific surface areas (up to 313 m2 g?1) and narrow pore size distributions are achieved in comparison to the micrometric material synthesized by the traditional sol–gel route. This study opens new perspectives in the development, by solvothermal methodologies, of multifunctional materials for advanced applications by improving the classical pyrochlore properties (magnetization, heat capacity, catalysis, conductivity, etc.). In particular, since catalytic reactions take place on the surface of catalysts, the high surface area of these materials makes them promising candidates for catalysts. Furthermore, their spherical morphology makes them appropriate for advanced technologies in, for instance, ceramic inkjet printers. 相似文献
20.
M. Bego?a Martín-García Dolores Bellido-Milla Andrés Jimenez-Jimenez María Purificación Hernández-Artiga 《Fresenius' Journal of Analytical Chemistry》1999,364(6):527-532
The determination of wear metals and metalloids in used lubricating oils allows the prediction of equipment failure. A number
of procedures to determine wear metals in lubricating oils by atomic spectrometry has been published. Industry has lately
shown a special interest in the determination of tin, since its appearance at certain levels in used oils indicates severe
engine wear. Therefore, a method for the determination of the total tin content in used lubricating oils by hydride generation-atomic
absorption spectrometry (HG-AAS) is described. Unused marine lubricating oils spiked with the analyte were digested in closed
vessels in a microwave oven and the diluted product was used for continuous stannane generation. There are many factors that
influence effective SnH4 generation; therefore, fractionary factorial design was used to obtain an adequate sensitivity and also to stabilize the
signal. Six variables were taken into account and a 26–2
IV design was used with spiked samples containing 30 ng g–1 Sn. The reproducibility, stability, calibration curve and limit of detection were established. The method was applied to
different kinds of used lubricating oils. In all cases, the results were higher than those obtained in the industry by simple
dilution.
Received: 30 September 1998 / Revised: 22 January 1999 / Accepted: 27 January 1999 相似文献