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51.
Influence of ionic liquid composition on the stability of polyvinyl chloride‐based ionic liquid inclusion membranes in aqueous solution
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Francisca Tomás‐Alonso Aurora M. Rubio Alfonso Giménez Antonia P. de los Ríos Maria J. Salar‐García Victor M. Ortiz‐Martínez Francisco J. Hernández‐Fernández 《American Institute of Chemical Engineers》2017,63(2):770-780
Membrane technology has gained significant importance with the incorporation of ionic liquids into their structure. This work shows the influence of ionic liquid composition on the stability of PVC‐based polymer ionic liquid inclusion membranes (PILIMs) in aqueous solution. Among the ILs investigated, those membranes which contain between 20 and 30%w/w of the least soluble, [OMIM+][PF6?] and [OMIM+][Ntf2?], exhibit losses of IL lower than 10%. For both ILs, the amount immobilized was maximum for the membranes with 30%w/w of IL (0.0838 and 0.0832 g, respectively). On the contrary, the ionic liquid loss increases as its solubility in water increase, reaching 99.52% when PILIMs are prepared with 70%w/w of [OMIM+][BF4?]. The results demonstrate that the stability of PILIMs depends on the solubility of the IL in the surrounding phase and the specific interaction between the IL and the polymeric support for PVC‐to‐IL ratios higher than 30%w/w. © 2016 American Institute of Chemical Engineers AIChE J, 63: 770–780, 2017 相似文献
52.
Concentrations and risks of polycyclic aromatic hydrocarbons in smoke-cured fish products in Nigeria
Chukwujindu M. A. Iwegbue Francisca I. Bassey Iwekumo Agbozu Eferhire Aganbi Grace Obi 《The International journal of environmental studies》2016,73(5):827-843
The concentrations of polycyclic aromatic hydrocarbons (PAHs) were determined in nine popular smoked fish species, (Clarias gariepinus, Parachana obscura, Heterotis niloticus, Pseudotolithus senegalensis, Gymnarchus niloticus, Ethmalosa fimbriata, Sardinella aurita, Scromber scrombus and Trachurus trachurus), in the Nigerian market by using gas chromatography-mass spectrometry after extraction by ultrasonication with hexane/dichloromethane. The mean concentrations of ∑16 PAHs in these species ranged from 52.4 μg kg?1 to 1230 μg kg?1. The estimated margins of exposure (MOE values) were less than 10,000 for C. gariepinus, G. niloticus and E. fimbriata indicating serious concern for the consumers’ health. The estimated excess cancer risk factors for these fish species investigated indicate that approximately 1 to 65 out of 106 equally exposed adults may suffer from cancer and cancer-related diseases during their lifetime through the ingestion of carcinogenic PAHs from smoked fish in their diet. 相似文献
53.
Sevilla P Martorell F Libenson C Planell JA Gil FJ 《Journal of materials science. Materials in medicine》2008,19(2):525-529
Conventional superelastic orthodontic wires are arch-shaped, have the same mechanical properties all along their length and
are used to correct the position of teeth. The disadvantage of these archwires is that there are different types of teeth
in the mouth and different forces are therefore needed to rectify their position. The aim of this work was to laser weld several
types of NiTi orthodontic wires that had different chemical compositions and superelastic properties, in order to adjust their
properties to different parts of the mouth. Microstructural changes, transformation stresses and temperatures, variations
in corrosion behaviour and ion release were studied in the welded wires. 相似文献
54.
Balcells L Abad L Rojas H Perez del Pino A Estrade S Arbiol J Peiro F Martínez B 《Small (Weinheim an der Bergstrasse, Germany)》2008,4(3):365-371
The transport properties across perovskite oxides heterointerfaces are analyzed. Epitaxial La(2/3)Ca(1/3)MnO3/SrTiO3 (LCMO/STO) heterostructures with different STO insulating-barrier thicknesses are systematically investigated and their behavior compared with LCMO/metal junctions. Atomic force microscopy (AFM) measurements in current-sensing mode show typical features associated with tunneling conduction. Careful analysis of the I-V curves across LCMO/STO heterointerfaces, using the Simmons model in the intermediate voltage range, clearly shows the existence of an interface-induced enhancement of the tunneling barrier of about 1.6 nm on the LCMO side. These results confirm recent theoretical studies predicting electronic phase segregation and the formation of an orbital-ordered insulating phase at the manganite-insulator interface that is a result of the reduction in the number of charge carriers at the interface. 相似文献
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56.
Drug Delivery: Thiolation and Cell‐Penetrating Peptide Surface Functionalization of Porous Silicon Nanoparticles for Oral Delivery of Insulin (Adv. Funct. Mater. 20/2016)
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Francisca Ortega‐García Juan Peragón 《Journal of the science of food and agriculture》2009,89(9):1565-1573
BACKGROUND: In this study the activities of phenylalanine ammonia‐lyase (PAL) and polyphenol oxidase (PPO) and the concentrations of hydroxytyrosol, tyrosol and oleuropein in olive tree (Olea europaea L. cv. Picual) leaves were investigated before and after cold stress by freezing. The air temperature fell to below ?7 °C and, according to the specific field conditions, four categories of orchard were selected: not cold stressed (NS), lightly cold stressed (LS), moderately cold stressed (MS) and heavily cold stressed (HS). RESULTS: In LS and MS samples the PAL specific activity at saturated substrate concentration rose 4.8‐ and 1.9‐fold respectively compared with NS samples. In HS samples the PAL activity declined by 47% compared with NS samples. A low level of PAL protein was detected in all samples affected by cold stress. In LS, MS and HS samples the PPO specific activity at saturated substrate concentration was 1.9‐, 4.4‐ and 9.8‐fold higher respectively than in NS samples. Km values also increased after cold stress. In MS and HS samples the concentration of oleuropein was 69 and 82% higher respectively than in NS samples, while the concentrations of hydroxytyrosol and tyrosol decreased. CONCLUSION: The response of PAL activity may be part of a recovery process of the olive leaf against cold stress, while the response of PPO and oleuropein may be part of an antioxidant protection mechanism. Copyright © 2009 Society of Chemical Industry 相似文献
60.
Kátia Gianni de Carvalho Lima Monika Francisca Kruger Jorge Behrens Maria Teresa Destro Mariza Landgraf Bernadette Dora Gombossy de Melo Franco 《LWT》2009,42(2):491-193
The study compared the growth capability of probiotic (Lactobacillus acidophilus La05, Lactobacillus casei Lc01 and Bifidobacterium animalis Bb12) and non-probiotic (Lactobacillus delbrueckii subsp bulgaricus and Streptococcus thermophilus) cultures on twenty-one culture media grouped according to selectivity: non-selective agars, selective agars without antibiotics and MRS agars containing different combinations of lithium chloride, cystein, bile salts and antibiotics. Four of these media were selected for quantitative enumeration of L. acidophilus La05, L. casei Lc01, and B. animalis Bb12. The best culture media and incubation conditions for enumeration of the probiotic cultures were: B. animalis: MRS agar with dicloxacillin, 37 °C or 42 °C, anaerobiosis; L. acidophilus: MRS agar with bile salts, 37 °C or 42 °C, aerobiosis; L. casei: MRS agar with lithium chloride and sodium propionate, 37 °C or 42 °C, aerobiosis or anaerobiosis. Plating on MRS with glucose replaced by maltose, 37 °C or 42 °C, anaerobiosis, will distinguish probiotic from non-probiotic cultures. For enumeration of each probiotic in a mixed culture, the following media and incubation conditions were recommended: B. animalis: 4ABC-MRS, 42 °C, anaerobiosis, L. acidophilus: LC medium, 42 °C, aerobiosis or anaerobiosis and L. casei: LP-MRS, 42 °C, aerobiosis or anaerobiosis. In all experiments, differences in counts using pour plating or surface plating were not significant (P ≤ 0.05). 相似文献