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941.
Cristina Torres-Duarte María Teresa Viana Rafael Vazquez-Duhalt 《Applied biochemistry and biotechnology》2012,168(4):864-876
Endocrine disrupting chemicals (EDCs) are known to mainly affect aquatic organisms, producing negative effects in aquaculture. Transformation of the estrogenic compounds 17??-estradiol (E2), bisphenol-A (BPA), nonylphenol (NP), and triclosan (TCS) by laccase of Coriolopsis gallica was studied. Laccase is able to efficiently transform them into polymers. The estrogenic activity of the EDCs and their laccase transformation products was evaluated in vitro as their affinity for the human estrogen receptor alpha (hER??) and for the ligand binding domain of zebrafish (Danio rerio) estrogen receptor alpha (zfER??LBD). E2, BPA, NP, and TCS showed higher affinity for the zfER??LBD than for hER??. After laccase treatment, no affinity was found, except a marginal affinity of E2 products for the zfER??LBD. Endocrine disruption studies in vivo on zebrafish were performed using the induction of vitellogenin 1 as a biomarker (VTG1 mRNA levels). The use of enzymatic bioreactors, containing immobilized laccase, efficiently eliminates the endocrine activity of BPA and TCS, and significantly reduces the effects of E2. The potential use of enzymatic reactors to eliminate the endocrine activity of EDCs in supply water for aquaculture is discussed. 相似文献
942.
Virginia Bravo Salvador Gil Ana M. Costero María N. Kneeteman Ursula Llaosa Pedro M.E. Mancini Luís E. Ochando Margarita Parra 《Tetrahedron》2012,68(24):4882-4887
The synthesis of two new 2,7-disubstituted phenanthrene-based bis oximes is described. The ability of these two compound for complexing heavy metal cations have been studied and complexation constants and complex stoichiometry for Cr3+ and Fe3+ complex have been determined. The fluorescent properties of ligand 2 make this compound able to act as a sensor able to discriminate between Cr3+ and Fe3+. Detection limits for these two cations have been evaluated. 相似文献
943.
Ana Sánchez‐Iglesias Nathalie Claes Dr. Diego M. Solís Dr. Jose M. Taboada Prof. Sara Bals Prof. Luis M. Liz‐Marzán Dr. Marek Grzelczak 《Angewandte Chemie (International ed. in English)》2018,57(12):3183-3186
A limiting factor of solvent‐induced nanoparticle self‐assembly is the need for constant sample dilution in assembly/disassembly cycles. Changes in the nanoparticle concentration alter the kinetics of the subsequent assembly process, limiting optical signal recovery. Herein, we show that upon confining hydrophobic nanoparticles in permeable silica nanocapsules, the number of nanoparticles participating in cyclic aggregation remains constant despite bulk changes in solution, leading to highly reproducible plasmon band shifts at different solvent compositions. 相似文献
944.
945.
José Alejandro Sánchez-Gutiérrez Monserrat Vázquez-Sánchez Dioselina Álvarez-Bernal María Daniela Mares-Quiñones Juan Ignacio Valiente-Banuet 《Analytical letters》2018,51(13):1986-1998
The total phenolic and flavonoid content, phenolic composition, and in vitro antioxidant capacity of ethanolic extracts of Ximenia parviflora Benth. var. parviflora fruits collected at Zinaparo, Michoacan (in central Mexico) were determined. Fruit extracts present a high scavenging activity of 2,2-diphenyl-1-picrylhydrazyl and 2,2′-azino-bis[3-ethylbenzothiazoline-6-sulfonic acid] radicals (71.49?±?0.11% and 85.00?±?1.29% inhibition, respectively). The four phenolic compounds identified in fruit extracts by high-performance liquid chromatography with diode array detection were gallic acid, chlorogenic acid, caffeic acid, and quercetin. X. parviflora fruits may be used as a starting material for the extraction of high value antioxidant phenolic compounds with potential applications in the pharmaceutical and dietary supplement industries. 相似文献
946.
Aydın Aktaş Ünzile Keleştemur Yetkin Gök Sevgi Balcıoğlu Burhan Ateş Muhittin Aygün 《Journal of the Iranian Chemical Society》2018,15(1):131-139
In this study, a series of unsymmetrically 2-morpholinoethyl-substituted benzimidazolium salts and their Ag(I)NHC complexes were synthesized. The 1,3-dialkylbenzimidazolium salts (1a–d) were synthesized in dimethylformamide at 80 °C temperature from the N-(2-morpholinoethyl)benzimidazole and alkyl halides. The Ag(I)NHC complexes (2a–d) were synthesized in dichloromethane at room temperature from the benzimidazolium salts and Ag2O. All compounds were characterized by spectroscopic techniques (NMR and FT-IR) and elemental analyses. Also, the salt 1c and complex 2c were characterized by single-crystal X-ray crystallography. Anticancer activities of 2-morpholinoethyl-substituted benzimidazolium salts and Ag(I)NHC complexes were investigated against the MCF-7 breast cancer cell line, and the IC30 and IC50 values of these compounds were found to be in the range of 241–490 and 6–14 µM, respectively. 相似文献
947.
L. Wojnárovits G. Földiák M. D'Angelantonio S. S. Emmi 《Research on Chemical Intermediates》2002,28(4):373-386
The OH radical-induced oxidation of p-cresol to p-methylphenoxyl radical was studied in aqueous solution in a wide pH range by means of pulse radiolysis combined with optical spectroscopy. OH-adduct cyclohexadienyl type radicals were identified as intermediates of the reaction. In the acidic pH range the first-order rate coefficient of phenoxyl radical formation was found linearly dependent on the H3O+ concentration yielding a bimolecular rate coefficient of 1.8 × 108 mol–1 dm3 s–1. In the alkaline range a linear dependence was found on the OH– concentration with rate coefficient of 4.9 × 1010 mol–1 dm3 s–1. These findings were interpreted in terms of acid-base catalysis of the H2O elimination from the OH-adduct. With the time resolution applied, 30 ns, the radical cation p-CH3C6H4OH+. was not observed as intermediate. 相似文献
948.
Estimation and correction of matrix effects in gas chromatographic pesticide multiresidue analytical methods with a nitrogen-phosphorus detector 总被引:1,自引:0,他引:1
Egea González FJ HernándezTorres ME Cuadros Rodríguez L Almansa López E Martínez Vidal JL 《The Analyst》2002,127(8):1038-1044
The assessment of matrix effects in the quantification of organophosphorus pesticides in fruit and vegetables by GC-NPD, were studied applying ANCOVA. Calibration curves prepared in solvent were compared with calibration curves prepared in a blank matrix extract for eight different commodities, establishing whether the matrix induces systematic or proportional errors in the quantification of the pesticides. In such cases correction functions were obtained and validated by quantifying spiked samples using solvent calibrations and applying the correction functions to the data obtained. The results were compared with those obtained by quantification using matrix-matching calibrations and with those from 100% recovery experiments. It was found that the matrix effects can be avoided using the correction functions. Finally the contribution of the correction functions to the uncertainty of the results was estimated as well as their stability during a four month period. 相似文献
949.
Synthesis and Structure Elucidation of New Regioisomeric 2‐Alkylamino‐6‐aryl‐8,9‐dihydropyrimido[4,5‐b][1,4]diazepin‐4(7H)‐ones 下载免费PDF全文
Braulio Insuasty Fabián Orozco Jairo Quiroga Rodrigo Abonía Manuel Nogueras Justo Cobo 《Journal of heterocyclic chemistry》2014,51(1):196-202
Novel 2‐Alkylamino‐6‐aryl‐8,9‐dihydropyrimido[4,5‐b][1,4]diazepin‐4(7H)‐ones 5a , 5b , 5c , 5d , 5e , 5f , 5g , 5h , 5i , 5j , 5k , 5l , 5m , 5n , 5o were prepared regioselectively by the reaction of 2‐alkylamino‐5,6‐diaminopyrimidin‐4(3H)‐ones 3a , 3b , 3c and dimethylamino propiophenones (Mannich bases) 4a , 4b , 4c , 4d , 4e , 4f . The combination of conventional heating and microwave irradiation approaches provided the possibility of working with both stable and sensitive diaminopyrimidines by controlling parameters such as reaction rates, temperature, and power of irradiation. All products were fully characterized by detailed NMR measurements. 相似文献
950.
P. Vaňura E. Makrlík Z. Valentová 《Journal of Radioanalytical and Nuclear Chemistry》2002,253(1):157-159
The extraction of cesium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H+B-) in the presence of Slovafol 909 (p-nonylphenylnonaethylene glycol, L) has been investigated. The equilibrium data have been explained assuming that the complexes HL+, HL2
+, CsL+ and CsL2
+ are extracted into the organic phase. The values of extraction and stability constants of the species in nitrobenzene saturated with water have been determined. 相似文献