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151.
Linlin Wu Masataka Ohtani Shingo Tamesue Yasuhiro Ishida Takuzo Aida 《Journal of polymer science. Part A, Polymer chemistry》2014,52(6):839-847
Novel clay–polymer composite hydrogels with high water content (up to 98 wt %) are developed, in which mechanical properties are reinforced by the formation of multiple ion‐pairs between the polymer chains and clay nanosheets (CNS). When a small amount of guanidinium‐pendant methacrylamide (0.1–0.2 wt %) is copolymerized with a neutral monomer (0.5–2.0 wt %) in an aqueous dispersion of CNS (1.0–3.0 wt %), a self‐standing hydrogel with satisfactory mechanical toughness and elasticity results, despite its high water content (95–98 wt %). The mechanical properties and swelling behaviors of the hydrogels can be tuned by the amount of the guanidinium‐pendant acrylamide. A systematic study indicates that the ion pairs, formed between the guanidinium groups in the polymer chains and the oxyanions on the surfaces of the CNS, serve as crosslinking points in the three‐dimensional network developed in these hydrogels. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 839–847 相似文献
152.
Determination of pharmaceutical compounds in sewage sludge using a standard addition method approach
Aida Garcia-Rodríguez Ester Sagristà Clàudia Fontàs Manuela Hidalgo Victòria Salvadó 《International journal of environmental analytical chemistry》2013,93(12):1199-1209
An analytical method for the simultaneous determination of eight pharmaceutical compounds in biosolids from urban wastewater treatment plants (WWTPs) was developed and validated. The compounds evaluated were non-steroidal anti-inflammatory drugs (naproxen, diclofenac, and ibuprofen), lipid regulators (clofibric acid), and antibiotics (sulfathiazole, sulfapyridine, sulfamethazine, and sulfamethoxazole). Ultrasound assisted extraction with a water–methanol solvent mixture (1:1, v:v) was performed and the compounds were then determined by liquid chromatography coupled with tandem mass spectrometry. The design of the method was based on the application of the standard addition calibration methodology to reduce matrix interferences. Validation procedures were conducted with rabbit excrements as blank samples. Recoveries of the target analytes ranged from 76 to 131% in spiked samples at 50, 200 or 1000 ng g?1 dry weight (dw). The relative standard deviations were in the range of 5–15% and the method detection limits ranged from 2 to 12 ng g?1dw. The method was applied to monitor pharmaceutical concentrations in biosolids from different WWTPs over an eight-month period (May to December 2011). Diclofenac, sulfapyridine and ibuprofen were detected in most of the samples whereas sulfamethazine and ibuprofen were the pharmaceuticals found in the highest concentrations (>200 ng g?1 dw on average). 相似文献
153.
El Sayed H. El Ashry Adel A.-H. Abdel-Rahman Mohamed Kattab Aida H. Shobier Richard R. Schmidt 《Journal of carbohydrate chemistry》2013,32(3):345-357
ABSTRACT Methyl 2,3,4-tri-O-acetyl-6-O-(p-tolylsulfonyl)-α-D-glucopyranoside (6), or its iodo analogue 7, were subjected to nucleophilic displacement with morpholine to give 8, deacetylation of which gave methyl 6-deoxy-6-(morpholin-4-yl)-α-D-glucopyranoside (3). Similarly, 11, 12 and 21 were prepared. The 6-deoxy-6-iodo derivative 16 was subjected to nucleophilic displacement with morpholine and subsequent acetylation to give 15. Deacetylation of 15 gave 17. The kinetic studies for the inhibition of β-D-glucosidase from sweet almond and using o-nitrophenyl β-D-glucopyranoside as substrate exhibited a K i value for 21 on the same order as 1-deoxynojirimycin whereas for 3, a K i value of lesser order was observed. 相似文献
154.
α, β, γ δ-Tetraphenylporphinatoaluminum carboxylate (TPPA10COR) and phenoxide (TPPA10Ar) bring about the polymerization of β-lactone and epoxide to give polymers with controlled chain length having a carboxylic ester or phenoxy group at the end of each polymer molecule. Acrylate (TPPA10COCH=CH2) and p-vinylphenoxide (TPPA1-OC6H4,CH[dbnd]CH2 (p)) as initiator give polyester or polyether macromer with narrow molecular weight distribution. 相似文献
155.
Masayuki Iguchi Kazuhiro Kasuya Yoshiyuki Sato Taku M. Aida Masaru Watanabe Richard L. Smith Jr. 《Cellulose (London, England)》2013,20(3):1353-1367
Viscosities of microcrystalline cellulose + 1-butyl-3-methylimidazolium acetate ([bmIm][Ac]) solutions (0.6–1.2 wt%) in contact with CO2 were measured at 312 K with a resonant vibrational viscometer. At 4 MPa and 312 K, the CO2 could reduce the viscosity of 1.2 wt% cellulose + [bmIm][Ac] solution by about 80 %, whereas N2 at the same conditions gave less than a 10 % reduction in viscosity. The viscosity-averaged degree of polymerization and IR spectrum showed that cellulose did not decompose during experiments and that [bmIm][Ac] acted as a non-derivatizing solvent during the dissolution and viscosity reduction process. Further, although CO2 does react with [bmIm][Ac] to form 1-butyl-3-methylimidazolium-2-carboxylate, the reaction seems to be reversible and it does not affect the cellulose. Thus, [bmIm][Ac] with CO2 provides an effective solvent for cellulose and the solvent system can probably be recycled or reused. 相似文献
156.
Aida Kulo Nedzad Mulabegovic Svjetlana Loga-Zec Karel Allegaert Jan de Hoon Rene Verbesselt 《Chromatographia》2014,77(11-12):803-812
In order to enhance the sensitivity and to develop a faster direct method for plasma and urine quantification of racemic ketorolac, its metabolites (p-hydroxy-ketorolac and ketorolac glucuronides) and ketorolac enantiomers, we developed an extraction procedure based on solid-phase extraction combined with specific and fast chromatographic separation. Extraction and chromatography resulted in cleaner chromatograms without interfering compounds. In both plasma and urine, linearity of the standard curves for racemic ketorolac and p-hydroxy-ketorolac was validated in the concentration range 0.025–10 mg L?1, while for ketorolac enantiomers in the concentration range 0.025–5 mg L?1. The lower limit of quantification was two times lower than in earlier described methods. The developed method was suitable for direct quantification of racemic ketorolac, p-hydroxy-ketorolac and ketorolac enantiomers in plasma and urine samples in women at delivery and in postpartum, enabling us to document significant intra-individual differences in pharmacokinetics between these physiological states. 相似文献
157.
Salma Abdeljalil Ines Ben Hmad Walid Saibi Bahia Amouri Wiem Maalej Marwa Kaaniche Aida Koubaa Ali Gargouri 《Applied biochemistry and biotechnology》2014,172(3):1599-1611
Stachybotrys microspora is a filamentous fungus characterized by the secretion of multiple hydrolytic activities (cellulolytic and non-cellulolytic enzymes). The production of these biocatalysts was studied under submerged culture using glucose, cellulose, and wheat bran as carbon sources. Endoglucanases, pectinases, xylanases, β-glucanases, chitinases, and proteases were induced on cellulose-based medium and repressed on glucose in both strains with higher amounts produced by the mutant. β-glucosidases were roughly equally produced by both strains under glucose and cellulose conditions. The yield of chitinases, β-glucanases, and proteases produced by Stachybotrys strains was as much higher than the commercialized lysing enzyme called “zymolyase,” currently used in yeast DNA extraction. In this context, we showed that S. microspora hydrolases can be successfully applied in the extraction of yeast DNA. 相似文献
158.
Analysis of cerebrospinal fluid γ‐aminobutyric acid by capillary electrophoresis with laser‐induced fluorescence detection
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Mercedes Casado Marta Molero Cristina Sierra Angels García‐Cazorla Aida Ormazabal Rafael Artuch 《Electrophoresis》2014,35(8):1181-1187
The measurement of γ‐aminobutyric acid (GABA) is suitable for investigating various neurological disorders. In this study, a sensitive and selective method for free GABA quantification in cerebrospinal fluid (CSF) has been standardised. This method is based on CE with LIF detection using 4‐fluoro‐7‐nitrobenzo‐2‐oxa‐1,3‐diazole (NBD‐F) as a derivatisating agent. The reaction conditions (NBD‐F concentration, pH, temperature and reaction time) and the electrophoretic parameters (run buffer composition and pH and separation voltage) were optimised to obtain the maximum derivatisation efficiency and electrophoretic resolution. The best resolution was obtained using 200 mM sodium borate, 10 mM SDS, 8.5 mM β‐CD, pH 10 and 20 kV voltage. The method was linear in the concentration range of 2.5–1000 nM with good inter‐ and intra‐assay precision values. The effects of CSF handling on free GABA concentrations were also evaluated. Our results show that the time delay between CSF collection and freezing strongly increases the CSF GABA values. Age‐related reference values were established in 55 paediatric controls. The influence of antiepileptic therapy on free CSF GABA was studied in 38 neuropaediatric patients. Significantly, higher GABA values were obtained in patients taking valproic acid or vigabatrin therapy, which are antiepileptic drugs that modulate GABA metabolism. 相似文献
159.
Miyamura Y Park C Kinbara K Leibfarth FA Hawker CJ Aida T 《Journal of the American Chemical Society》2011,133(9):2840-2843
When poly(isopropylidene diallylmalonate) rich in threo-disyndiotactic sequences (st(rich)-2) was utilized as a cross-linkable ink for microcontact printing, the resultant submicrometer-scale patterns featuring 700 and 300 nm wide stripes were successfully insolubilized while maintaining their high dimensional integrity by heat-induced cross-linking with elimination of CO(2) and acetone. In sharp contrast, although the thermal properties and reactivities of a polymer rich in threo-diisotactic sequences (it(rich)-2) and a polymer having low stereoregularity (2(low)) are little different from those of st(rich)-2, the patterns printed with these reference polymers collapsed considerably upon heating as a result of a volume shrinkage effect. The striking difference between st(rich)-2 and the other two polymers most likely arises from the nanofiber-forming character of st(rich)-2, where the printed stripes are porous and much less affected by the volume shrinkage of individual nanofibers. 相似文献
160.
Aida Taira Toma Takahiro Kanada Satoshi 《Journal of Solid State Electrochemistry》2020,24(6):1415-1425
Journal of Solid State Electrochemistry - It is well known that reducing particle size and/or hollowing the particles improves the electrochemical performance, especially the rate capability, of... 相似文献