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981.
E. Jóna L’. Lajdová M. Loduhová S. Lendvayová V. Pavlík J. Moncol’ P. Lizák S. C. Mojumdar 《Journal of Thermal Analysis and Calorimetry》2012,108(3):921-926
Thermogravimetry (TG), derivative thermogravimetry (DTG) and infrared (IR) spectroscopy have been applied to the investigation of the thermal behaviour and structure of the compounds [Cu(2-Clbz)2(nia)2(H2O)2] (I), [Cu(2-Clbz)2(nia)2]·H2O (II), [Cu(2-Brbz)2(nia)2]·2H2O (III), [Cu(2-Brbz)2(nia)2(H2O)] (IV), where 2-Clbz and 2-Brbz?=?2-chloro- and 2-bromobenzoate anions, nia?=?nicotinamide, H2O?=?water molecules. Thermal decomposition of all studied compounds proceeds in three steps. Heating the compounds first results in a release of non-coordinated and/or coordinated water molecules. The final product of thermal decomposition was CuO. The thermal stability of the complexes can be ordered in the sequence: I<IV<III<II. Nicotinamide is coordinated to Cu(II) through the nitrogen atom of the heterocyclic ring. IR data suggest the unidentate coordination of benzoate anions to Cu(II) in complexes I, IV and bidentate coordination in complexes II and III. 相似文献
982.
Lubomír Lap?ík Barbora Lap?íková Ivo Krásny Ivana Kupská Richard W. Greenwood Kristian E. Waters 《Plasma Chemistry and Plasma Processing》2012,32(4):845-858
It was found in this study that the air plasma treatment of particular kaolinite has led to the change of its wettability, which was reflected in the decreased values of water contact angles of wetting from 88.7° for virgin kaolinite to 86.3° for 30?min air plasma treated one. Plasma treated samples show higher average surface energies in the wide range of coverage regimes in comparison to the virgin samples as determined by inverse gas chromatography. Results of these measurements confirmed our assumption, that air plasma treatment activates surface energy of the crystal planes of the kaolinite as reflected in the broadened dispersive surface energy distribution after 10?min treatment time. However with prolonged 30?min treatment time the dispersive surface energy distribution profile was decreased. We assume, that the latter decrease reflects the distorsion of the crystal lattice of the kaolinite as confirmed by FTIR analysis as reflected in changes of Si?CO?CSi and Al2O?CH characteristic absorption bands. Calculated dispersive surface free energy for 24?% surface coverage was increased from original 35?mJ/m2 to 40.3 and 40.8?mJ/m2 for 10 and 30?min treatment times. There were determined yield locus and flow function dependencies at different stress levels for virgin and different time plasma treated samples (flow index??ff c , effective angle of internal friction???? e , unconfined yield strength???? c ). It was found that by plasma treatment the character of the flow was shifting from region of very cohesive (ff c ?=?2.39) to the cohesive (ff c ?=?3.19). For untreated samples effective angle of internal friction was decreased with increasing applied consolidation stress, while for plasma treated kaolinite it was increased. 相似文献
983.
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
984.
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
985.
M.T.S. Alcântara A.J.C. Brant D.R. Giannini J.O.C.P. Pessoa A.B. Andrade H.G. Riella A.B. Lugão 《Radiation Physics and Chemistry》2012,81(9):1465-1470
In this work several hydrogels were obtained with two different poly(vinyl alcohol)s/PVAs as the main polymer in aqueous solutions containing 10% of PVA, 0.6% of agar, and 0.6% of κ-carrageenan (KC), cross-linked by gamma-rays from a 60Co irradiation source. The PVAs tested have different degrees of hydrolysis and viscosities at 4% with values closed to 30 mPa s. The aqueous polymeric solutions were prepared using two distinct processes: the simple process of heating–stirring and that of making use of an autoclave. The purpose of this study was to evaluate the influence of the dissolution process by means of both methods on the hydrogels’ properties obtained. These were investigated by means of degree of cross-linking/gel fraction, degree of swelling in water, and some mechanical properties. The results that are obtained for hydrogels synthesized from solutions of PVA, agar, KC, and blends thereof prepared by both dissolution processes showed higher degrees of swelling for hydrogels from the autoclaved polymer solutions than those from the solutions prepared by simple heating–stirring process. Furthermore, their hydrogels containing totally hydrolyzed PVA displayed higher tensile strength and lower elongation properties. 相似文献
986.
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
987.
Helicenophyrins: Expanded Carbaporphyrins Incorporating Aza[5]helicene and Heptacyclic S‐Shaped Aza[5]helicene Motifs 下载免费PDF全文
Dr. Bartosz Szyszko Monika Przewoźnik Dr. Michał J. Białek Dr. Agata Białońska Prof. Dr. Piotr J. Chmielewski Dr. Jakub Cichos Prof. Dr. Lechosław Latos‐Grażyński 《Angewandte Chemie (International ed. in English)》2018,57(15):4030-4034
Incorporation of phenanthrene into a hexaphyrin(1.1.1.1.1.0) frame resulted in intramolecular ring fusion, thus giving rise to chiral helicenophyrins. These molecules contain helicene and porphyrin features by incorporating either an aza[5]helicene or heptacyclic S‐shaped aza[5]helicene. 相似文献
988.
989.
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
990.
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