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91.
Roberta Sanna Davide Sanna Valeria Alzari Daniele Nuvoli Sergio Scognamillo Massimo Piccinini Massimo Lazzari Emilia Gioffredi Giulio Malucelli Alberto Mariani 《Journal of polymer science. Part A, Polymer chemistry》2012,50(19):4110-4118
Thermoresponsive poly(N‐vinylcaprolactam) nanocomposite hydrogels containing graphene were successfully prepared by frontal polymerization. High concentration of graphene (5.0 mg/mL) was obtained by direct graphite sonication in the self‐same liquid monomer, thus avoiding any chemical manipulation and obtaining “real” graphene as nanofiller instead of one of its more or less oxidized derivative, which is what generally reported in published reports. Furthermore, the corresponding nanocomposites were obtained without using any solvent to be eventually removed. The materials were fully characterized by RAMAN, SEM, and TEM, and their swelling behavior and rheological properties were investigated. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 相似文献
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Francesco Trotta Luisa Costa Giancarlo Costa 《Journal of inclusion phenomena and macrocyclic chemistry》2002,44(1-4):341-344
Optically pure binaphthyl structures make up the most important family of auxiliaries, ligands and catalysts used in enantioselective reactions. Syntheses of 2,2'-disubstituted-1,1'-binaphtyl derivatives were carried out one pot in water by oxidative coupling with FeCl3 in the presence of - and -cyclodextrin (CD) derivatives. A new efficient and inexpensive preparation of trihydroxyethyl- and tri-2-hydroxypropyl- - and -CD afforded these powerful solubilizing agents. The resolution of racemic 2,2'-dihydroxy-1,1'-binaphthyl was easily achieved by semipreparative HPLC separating diastereomers obtained from the reaction with (-)menthyl chloroformate. Final basic hydrolysis afforded the enantiomerically pure product. 相似文献
94.
Anderson KL Lyman RL Moats WA Hansen AP Rushing JE 《Journal of AOAC International》2002,85(3):546-550
A microbial receptor assay (Charm II Tablet Beta-Lactam Test) and liquid chromatography (LC) were compared for determination of penicillin G (PG) and amoxicillin (AMOX) in reconstituted milk powder. Nonfat dry milk and whole dry milk were reconstituted (10%, w/v) to concentrations of 0, 2.5, 5, 7.5, and 10 ppb PG; nonfat dry milk was reconstituted (10%, w/v) to 0, 7.5, 10, and 15 ppb AMOX. Reconstituted samples were analyzed blindly by each method. Concentrations determined by both methods demonstrated good agreement. A significant difference between methods (p < or = 0.05) was observed only for 7.5 ppb PG in defatted dry milk. Significant differences were not observed between known concentrations and concentrations determined by the Charm II assay for PG or AMOX in defatted dry milk and PG in whole dry milk. Results by LC showed significant differences (p < 0.05) between known and measured concentrations at 10 ppb PG in both milks and 0 ppb AMOX in defatted dry milk. These results suggest that both the microbial receptor assay and LC may be useful for determination of PG and AMOX near safe level and tolerance, respectively, in reconstituted milk powder. 相似文献
95.
The distribution and the origin of carbon and nitrogen in sediments of an Italian lagoon--located north-east of Ravenna town--were investigated. From 1957 to 1976, the lagoon had been affected by a strong industrial pollution due to an important petrochemical complex. At present, industrial and domestic waste waters undergo a treatment process before being discharged into the lagoon. Sediment samples from 10 locations throughout the lagoon were analysed, in order to document the spatial and vertical distribution of C and N. Data show a very strong variability (organic carbon content varies between 8.9% and 0.14%) and the highest values were found in the immediate vicinity of the industrial discharge. Sediment organic matter shows allochthonous origin in proximity of industrial discharge and autochthonous origin in the remaining areas. 相似文献
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98.
Bediako-Amoa I Silerova R Kraatz HB 《Chemical communications (Cambridge, England)》2002,(20):2430-2431
Extensive intermolecular hydrogen bonding in ferrocenoyl glycylcystamine gives rise to a novel ordered double helical arrangement with a helical pitch height of 14 A. 相似文献
99.
An ethylcarbonate derivative of beta-cyclodextrin (beta-CD) with three substituents per molecule, hydroxypropyl-beta-CD and native alpha-CD have been tested as resolving agents in the capillary zone electrophoresis (CZE) separation of the four enantiomers of the herbicides mecoprop and dichlorprop. The performances of the three compounds have been quantified by means of two-levels full factorial design and the inclusion constants were calculated from CZE migration time data. Possible structure of inclusion complexes have been proposed, on the basis of molecular mechanics simulations. 相似文献
100.