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901.
Pedrouzo M Reverté S Borrull F Pocurull E Marcé RM 《Journal of separation science》2007,30(3):297-303
A method was developed to determine 11 pharmaceutical compounds in water samples. The method uses SPE and HPLC coupled to MS (LC/MS) using ESI in both positive and negative modes. Three different sorbents were compared for the extraction of analytes from river and sewage treatment plant (STP) waters and OASIS HLB provided the best results. For the solid-phase extraction of 500 mL of river water samples, the recoveries were between 41 and 101% with the exception of acetaminophen, salicylic acid and naproxen. The LODs were between 3 and 5 ng/L for all the compounds, except naproxen which had an LOD of 15 ng/L. Acetaminophen, caffeine, carbamazepine, bezafibrate and ibuprofen were found in three of the tested river samples at ng/L levels and among them, the highest values were for caffeine and bezafibrate with 305 and 363 ng/L, respectively. For the influent and effluent water samples of the STP, volumes of 100 and 250 mL were used, respectively, to obtain acceptable recoveries. All the compounds showed recoveries between 33 and 91% for effluent samples and 33-72% for influent samples, with the exception of acetaminophen, salicylic acid and bezafibrate, which had lower recoveries. The method developed enabled pharmaceuticals in the influent and effluent sewage waters to be determined in five campaigns carried out between February 2004 and June 2005. Several pharmaceuticals were found in the influent samples: for instance, maximum concentrations of ibuprofen and caffeine were 6 and 40 microg/L, respectively. 相似文献
902.
Terrado M Kuster M Raldúa D Lopez de Alda M Barceló D Tauler R 《Analytical and bioanalytical chemistry》2007,387(4):1479-1488
Data sets obtained from quantitative analysis of seventeen pesticides in water samples from a network of irrigation and drainage
channels in the Ebro river delta (Catalonia, NE Spain) have been analysed by chemometric and geostatistical methods. Samples
were taken at fourteen locations during the main rice-growing season, from May to August 2005. Principal-component analysis
enabled investigation of the spatial and temporal distribution of the main pollution patterns caused by application of pesticides
in the region under study. A first pesticide-contamination pattern from the Ebro river was differentiated from a second more
specific pattern from the water-drainage channels of the delta, collected from the rice fields. The seasonal peak in this
more specific rice pesticide source was observed in July. Coupling the results from chemometric data analysis with use of
geostatistical methods was shown to be a useful procedure for discovery of the most significant spatial and monthly variations
of the main pesticide-contamination patterns, taking into account the particular geographical structure of the area under
study. 相似文献
903.
Rahman R Wellard CJ Bradbury FR Prada M Cole JH Klimeck G Hollenberg LC 《Physical review letters》2007,99(3):036403
The Stark shift of the hyperfine coupling constant is investigated for a P donor in Si far below the ionization regime in the presence of interfaces using tight-binding and band minima basis approaches and compared to the recent precision measurements. In contrast with previous effective mass-based results, the quadratic Stark coefficient obtained from both theories agrees closely with the experiments. It is also shown that there is a significant linear Stark effect for an impurity near the interface, whereas, far from the interface, the quadratic Stark effect dominates. This work represents the most sensitive and precise comparison between theory and experiment for single donor spin control. Such precise control of single donor spin states is required particularly in quantum computing applications of single donor electronics, which forms the driving motivation of this work. 相似文献
904.
Jokiel M Shcharbin D Janiszewska J Urbanczyk-Lipkowska Z Bryszewska M 《Journal of fluorescence》2007,17(1):73-79
The interactions between polycationic poly-lysine dendrimers and hydrophobic fluorescent probes (anionic ANS and neutral Prodan)
were studied. R121 and R131 dendrimers were not able to interact with anionic and neutral hydrophobic groups. R124 was able
to interact with neutral and anionic hydrophobic fluorescent probes, however mainly through hydrophobic forces. Dendrimers
R155 and R169 showed the maximal effects. The strongest interactions observed for R169 can be explained by intramolecular
folding (stacking) of its two L-proline residues. Using double fluorescence titration technique for ANS probe allowed to receive
such constant of binding and the number of binding centers: for R121, 1.8·103 (mol/l)−1 and 1.07; for R124, 12.1·103 (mol/l)−1 and 0.48; for R131, 4.7·103 (mol/l)−1 and 0.48; for R155, 9.2·103 (mol/l)−1 and 1.36; for R169, 39.6·103 (mol/l)−1 and 0.97. Thus, neutral and anionic hydrophobic probes can be used for the fast preliminary screening of binding properties
of newly synthesized polycationic dendrimers. 相似文献
905.
Self‐Assembled Architectures with Segregated Donor and Acceptor Units of a Dyad Based on a Monopyrrolo‐Annulated TTF–PTM Radical 下载免费PDF全文
Manuel Souto Dr. Marta V. Solano Morten Jensen Dan Bendixen Francesca Delchiaro Prof. Alberto Girlando Prof. Anna Painelli Prof. Jan O. Jeppesen Prof. Concepció Rovira Dr. Imma Ratera Prof. Jaume Veciana 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(24):8816-8825
An electron donor–acceptor dyad based on a polychlorotriphenylmethyl (PTM) radical subunit linked to a tetrathiafulvalene (TTF) unit through a π‐conjugated N‐phenyl–pyrrole–vinylene bridge has been synthesized and characterized. The intramolecular electron transfer process and magnetic properties of the radical dyad have been evaluated by cyclic voltammetry, UV/Vis spectroscopy, vibrational spectroscopy, and ESR spectroscopy in solution and in the solid state. The self‐assembling abilities of the radical dyad and of its protonated non‐radical analogue have been investigated by X‐ray crystallographic analysis, which revealed that the radical dyad produced a supramolecular architecture with segregated donor and acceptor units in which the TTF subunits were arranged in 1D herringbone‐type stacks. Analysis of the X‐ray data at different temperatures suggests that the two inequivalent molecules that form the asymmetric unit of the crystal of the radical dyad evolve into an opposite degree of electronic delocalization as the temperature decreases. 相似文献
906.
907.
Liubov I. Panferova Fedor M. Miloserdov Dr. Anton Lishchynskyi Dr. Marta Martínez Belmonte Dr. Jordi Benet‐Buchholz Prof. Vladimir V. Grushin 《Angewandte Chemie (International ed. in English)》2015,54(17):5218-5222
Four new well‐defined CuI complexes bearing a C2F5 ligand have been prepared and fully characterized: [(Ph3P)2CuC2F5] ( 2 ), [(bpy)CuC2F5] ( 3 ), [(Ph3P)Cu(phen)C2F5] ( 4 ), and [(IPr*)CuC2F5] ( 5 ). X‐ray structures of all four have been determined, showing that the C2F5‐ligated Cu atom can be di‐ ( 5 ), tri‐ ( 2 and 3 ), and tetracoordinate ( 4 ). The mixed phen‐PPh3 complex 4 is a highly efficient fluoroalkylating agent for a broad variety of acid chlorides. This high‐yielding transformation represents the first general method for the synthesis of RCOC2F5 from the corresponding RCOCl. 相似文献
908.
A Reevaluation of the Photolytic Properties of 2‐Hydroxybenzophenone‐Based UV Sunscreens: Are Chemical Sunscreens Inoffensive? 下载免费PDF全文
Dr. Marta T. Ignasiak Prof. Dr. Chantal Houée‐Levin Dr. Gabriel Kciuk Prof. Dr. Bronislaw Marciniak Dr. Tomasz Pedzinski 《Chemphyschem》2015,16(3):628-633
The excited states of a set of popular sunscreen agents (2‐hydroxybenzophenone, oxybenzone, and sulisobenzone) are studied by using femto‐ and nanosecond time‐resolved spectroscopy. Upon excitation, the compounds undergo an ultrafast excited‐state intramolecular proton transfer (ESIPT) reaction as the major energy‐wasting process and the rate constant of this reaction is k=2×1012 s?1. The ESIPT yields a keto conformer that undergoes a fast, picosecond internal conversion decay. However, a photodegradative pathway is a monophotonic H?O bond breakage that subsequently leads to trace yields of phenoxyl radicals. Because potentially harmful phenoxyl radicals are formed upon irradiation of sunscreen agents, care should be taken about their reactivity towards biologically relevant compounds. 相似文献
909.
910.
Marta Overchuk Martha P.F. Damen Kara M. Harmatys Martin G. Pomper Juan Chen Gang Zheng 《Photochemistry and photobiology》2020,96(3):718-724
Targeted photodynamic therapy (PDT) combined with image-guided surgical resection is a promising strategy for precision cancer treatment. Prostate-specific membrane antigen (PSMA) is an attractive target due to its pronounced overexpression in a variety of tumors, most notably in prostate cancer. Recently, we reported a pyropheophorbide-based PSMA-targeted agent, which exhibited long plasma circulation time and effective tumor accumulation. To further advance PSMA-targeted photodynamic therapy by harvesting tissue-penetrating properties of the NIR light, we developed a bacteriochlorophyll-based PSMA-targeted photosensitizer (BPP), consisting of three building blocks: (1) a PSMA-affinity ligand, (2) a peptide linker to prolong plasma circulation time and (3) a bacteriochlorophyll photosensitizer for NIR fluorescence imaging and photodynamic therapy (Qy absorption maximum at 750 nm). BPP exhibited excellent PSMA-targeting selectivity in both subcutaneous and orthotopic mouse models. The nine D-peptide linker in BPP structure prolonged its plasma circulation time (12.65 h). Favorable pharmacokinetic properties combined with excellent targeting selectivity enabled effective BPP tumor accumulation, which led to effective PDT in a subcutaneous prostate adenocarcinoma mouse model. Overall, bright NIR fluorescence of BPP enables effective image guidance for surgical resection, while the combination of its targeting capabilities and PDT activity allows for potent and precise image-guided photodynamic treatment of PSMA-expressing tumors. 相似文献