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271.
Summary Solid-phase microextraction is a relatively recent extraction technique for sample preparation. It has been used successfully
to analyse environmental pollutants in a variety of matrices such as soils, water and air. In this work, a simple and rapid
method for the analysis of volatile organic and polar compounds from polluted groundwater samples by SPME coupled with gas
chromatography (GC) is described. Different types of fibres were studied and the extraction process was optimised. The fibre
that proved to be the best to analyse this kind of samples was CAR-PDMS. The method was validated by analysis of synthetic
samples and comparison with headspace—GC. The optimised method was successfully applied to the analysis of ground-water samples. 相似文献
272.
M. Pons S. Nonell I. García-Moreno Á. Costela R. Sastre 《Applied physics. B, Lasers and optics》2002,75(6-7):687-694
A dual-beam pulsed-laser time-resolved thermal lens (TRTL) has been used to study the heat dissipation effects in solid polymers
employed as laser dyes. The laser-dye samples studied are polymer solutions of rhodamine 6G (Rh6G), namely homopolymers of
methyl methacrylate (MMA) and copolymers of methyl methacrylate and 2-hydroxyethyl methacrylate (HEMA) with MMA:HEMA compositions
1:1 and 7:3 vol./vol., where the dye is either dissolved or modified and copolymerized with methacrylate monomers. The long-term
stability of the laser material is independent of the thermal diffusivity of the samples, as determined by the TRTL technique.
This suggests that the rate of heat dissipation does not play a major role in the photostability of the samples. In contrast,
the TRTL experiments have revealed permanent changes in the optical properties of the polymers when subjected to a large number
of laser pulses. This is explained in terms of permanent plastic deformation of the matrices.
Received: 19 June 2002 / Revised version: 1 August 2002 / Published online: 15 November 2002
RID="*"
ID="*"Dedicated to Prof. S.E. Braslavsky on the occasion of her 60th birthday. This work was presented at the V Congreso de
Fotoquímica, Torremolinos, Spain, 2001
RID="**"
ID="**"Corresponding author. Fax: +34-93/205-6266, E-mail: s.nonell@iqs.es 相似文献
273.
Antonio de León Josefina Pons Jordi García-Antón Xavier Solans Mercè Font-Bardía Josep Ros 《Polyhedron》2009
Mononuclear palladium(II) complexes containing a pyrazole-thioether ligand, with general formula trans-[Pd(X)2(bddo)] (X = CN− (1), SCN− (2) or N3− (3); bddo = 1,8-bis(3,5-dimethyl-1-pyrazolyl)-3,6-dithiaoctane), have been prepared. Similar reactivity carried out with pyridine or triphenylphosphine has been assayed. When pyridine is used, a mixture of [Pd(bddo)(py)2](BF4)2 ([4](BF4)2) and [Pd(bddo)](BF4)2 is obtained. When triphenylphosphine is used, only [Pd(bddo)](BF4)2 is obtained. The complexes have been characterised by elemental analyses, conductivity measurements, IR and NMR spectroscopies. X-ray crystal structure of trans-[Pd(SCN)2(bddo)] (2) is presented. In this complex the metal atom is coordinated by the two azine nitrogen atoms of the pyrazole rings and two SCN− anions in trans disposition. 相似文献
274.
A Trifluorinated Thiazoline Scaffold Leading to Pro‐apoptotic Agents Targeting Prohibitins 下载免费PDF全文
Dr. Alba Pérez‐Perarnau Dr. Sara Preciado Dr. Claudia Mariela Palmeri Cristina Moncunill‐Massaguer Dr. Daniel Iglesias‐Serret Dr. Diana M. González‐Gironès Dr. Miriam Miguel Dr. Satoki Karasawa Dr. Satoshi Sakamoto Dr. Ana M. Cosialls Dr. Camila Rubio‐Patiño José Saura‐Esteller Dr. Rosario Ramón Dr. Laia Caja Dr. Isabel Fabregat Dr. Gabriel Pons Prof. Hiroshi Handa Prof. Fernando Albericio Prof. Joan Gil Prof. Rodolfo Lavilla 《Angewandte Chemie (International ed. in English)》2014,53(38):10150-10154
A new class of small molecules, with an unprecedented trifluorothiazoline scaffold, were synthesized and their pro‐apoptotic activity was evaluated. With an EC50 in the low micromolar range, these compounds proved to be potent inducers of apoptosis in a broad spectrum of tumor cell lines, regardless of the functional status of p53. Fast structure–activity relationship studies allowed the preparation of the strongest apoptosis‐inducing candidate. Using a high performance affinity purification approach, we identified prohibitins 1 and 2, key proteins involved in the maintenance of cell viability, as the targets for these compounds. 相似文献
275.
March R Pons J Ros J Clegg W Alvarez-Larena A Piniella JF Sanz J 《Inorganic chemistry》2003,42(23):7403-7409
The series of complexes [CdX(2)(C(5)H(4)NCOOR)] (X = Cl or Br; R = Me, Et, Pr(n)() or Pr(i)()) and [CdX(2)(C(5)H(4)NCOOR)(2)] (X = I; R = Me, Et, Pr(n)(), or Pr(i)()) have been obtained by the addition reaction of esters of 2-pyridinecarboxylic acid to cadmium(II) halides. X-ray crystal structures of two complexes [CdI(2)(C(5)H(4)NCOOR)(2)], R = Me (10) and R = Pr(n)() (12), have been determined. In both cases, the structure consists of discrete neutral monomeric units where the cadmium atom has a distorted octahedral coordination with CdI(2)N(2)O(2) core, two halides being in cis disposition. Structural information is compared with that deduced from (113)Cd CPMAS NMR experiments. Chemical shift anisotropies are discussed in terms of distortions produced in cadmium octahedra. The orientation of the principal axes of (113)Cd shielding tensor is also analyzed and related to the disposition of ligands in the structures of two analyzed compounds. 相似文献
276.
F. A. López M. C. Ramirez J. A. Pons A. López-Delgado F. J. Alguacil 《Journal of Thermal Analysis and Calorimetry》2008,94(2):517-522
This study presents an evaluation of the decomposition kinetic of low-grade nickeliferous laterite by thermogravimetric analysis.
Kinetic parameters were calculated using the Ozawa and the iso-conversional Friedman methods. Simplified kinetics models like
those based on the reaction order were also applied for the simulations. Two-dimensional shrinkage models of the reaction
interface mechanism were adopted as describing the thermal transformation process from non-isothermal kinetic analysis. The
iso-conversional method (model-free kinetics) reveals that the decomposition of low-grade nickeliferous laterite does not
follow a single mechanism because the determined activation energies and pre-exponential factor are not constant during the
course of the reaction. 相似文献
277.
Josep Freixas Dorota Marciniak Montserrat Pons 《European Journal of Operational Research》2012,216(2):367-375
In this paper, we characterize the games in which Johnston, Shapley-Shubik and Penrose-Banzhaf-Coleman indices are ordinally equivalent, meaning that they rank players in the same way. We prove that these three indices are ordinally equivalent in semicomplete simple games, which is a newly defined class that contains complete games and includes most of the real-world examples of binary voting systems. This result constitutes a twofold extension of Diffo Lambo and Moulen’s result (Diffo Lambo and Moulen, 2002) in the sense that ordinal equivalence emerges for three power indices (not just for the Shapley-Shubik and Penrose-Banzhaf-Coleman indices), and it holds for a class of games strictly larger than the class of complete games. 相似文献
278.
Prof. María De las Nieves Piña Sergi Burguera Jordi Buils Miquel Àngel Crespí Julian Ernesto Morales Jordi Pons Prof. Antonio Bauzá Prof. Dr. Antonio Frontera 《Chemphyschem》2022,23(8):e202200010
Long range substituent effects in regium bonding interactions involving Au(I) linear complexes are investigated for the first time. The Au(I) atom is coordinated to two para-substituted pyridine ligands. The interaction energy (RI-MP2/def2-TZVP level of theory) of the π-hole regium bonding assemblies is affected by the pyridine substitution. The Hammett's plot representations for several sets of Lewis bases have been carried out and, in all cases, good regression plots have been obtained (interaction energies vs. Hammett's σ parameter). The Bader's theory of “atoms-in-molecules” has been used to evidence that the electron density computed at the bond critical point that connects the Au-atom to the electron donor can be used as a measure of bond order in regium bonding. Several X-ray structures retrieved from the Cambridge Structural Database (CSD) provide experimental support to the existence of π-hole regium bonding in [Au(Py)2]+ derivatives. 相似文献