排序方式: 共有59条查询结果,搜索用时 15 毫秒
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Mouna Nacef Mohamed Lyamine Chelaghmia Abed Mohamed Affoune Maxime Ponti 《Electroanalysis》2019,31(1):113-120
Novel nickel‐copper modified pencil graphite electrode (Ni?Cu/PGE) was fabricated and used as non‐enzymatic sensor for glucose determination. Ni and copper were electrodeposited on PGE using cyclic voltammetry. Morphology and composition of the modified PGE electrode were characterized by field‐emission gun scanning electron microscopy (FEG‐SEM), energy‐dispersive X‐ray spectroscopy (EDX) and Fourier transform infrared spectroscopy (FT‐IR). Electrochemical oxidation of glucose was evaluated by cyclic voltammetry as well as by amperometry. Electrochemical measurements indicate that the Ni?Cu/PGE exhibits a high sensitivity of 2951 μA mM?1 cm?2, and a low detection limit of 0.99 μM which are, respectively, three times higher and twice lower than that on Ni/PGE prepared in the same conditions. Moreover, Ni?Cu/PGE exhibits a wider linear range from 1 to 10000 μM with a rapid response time within 2 s. Moreover, Ni?Cu/PGE showed a remarkable stability. The electrode was successfully applied for determination of glucose concentration in human blood without significant interference from potential endogenic interferents. The good applicability of the elaborated sensor made Ni?Cu/PGE promising for the development of effective and inexpensive non‐enzymatic glucose sensor. 相似文献
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A flow-injection system with a carbon paste detector is proposed for the determination of copper in complex media at +0.050 V vs. Ag/AgCl. Both the reduction current peak of Cu(II) and the oxidation peak of Cu(I) (obtained in the presence of hydroxylamine in the reagent stream) were proportional to the Cu(II) concentration in the original sample. The stabilization of Cu(I) in the hydroxylamine system provides a novel approach; the inherent repeatability of operation of flow-injection systems (timing, etc.) proved ideal for this utilization. Acidified Cu(II) samples containing additional metal ions [Fe(lI), Zn(II), Pb(II)] and relatively high concentrations of serum albumin were analysed. A chelating column retained heavy metal ions while allowing albumin to run to waste. The retained metals were subsequently eluted with nitric acid into a stream of sodium acetate or sodium acetate-hydroxyl- amine. Before reaching the detector, the pH of the sample plug was adjusted. With the hydroxylamine system, Fe(III) interference was minimized and the sensitivity and reproducibility were improved. The sample throughput was 25 h?1. National Bureau of Standards Standard Reference Material 909 Human Serum was used to test the method. 相似文献
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Andrew D. Wiersum Estelle Soubeyrand‐Lenoir Dr. Qingyuan Yang Dr. Beatrice Moulin Vincent Guillerm Dr. Mouna Ben Yahia Dr. Sandrine Bourrelly Dr. Alexandre Vimont Dr. Stuart Miller Dr. Christelle Vagner Prof. Marco Daturi Dr. Guillaume Clet Dr. Christian Serre Dr. Guillaume Maurin Dr. Philip L. Llewellyn 《化学:亚洲杂志》2011,6(12):3270-3280
In addition to its high thermal stability, repetitive hydration/dehydration tests have revealed that the porous zirconium terephthalate UiO‐66 switches reversibly between its dehydroxylated and hydroxylated versions. The structure of its dehydroxylated form has thus been elucidated by coupling molecular simulations and X‐ray powder diffraction data. Infrared measurements have shown that relatively weak acid sites are available while microcalorimetry combined with Monte Carlo simulations emphasize moderate interactions between the UiO‐66 surface and a wide range of guest molecules including CH4, CO, and CO2. These properties, in conjunction with its significant adsorption capacity, make UiO‐66 of interest for its further evaluation for CO2 recovery in industrial applications. This global approach suggests a strategy for the evaluation of metal–organic frameworks for gas‐based applications. 相似文献
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T.B. Bouetou A. Souleymanou V.K. Kuetche F. Mouna T.C. Kofane 《Journal of Mathematical Analysis and Applications》2011,377(1):269-273
In this paper, based upon a jet bundle formalism, we investigate the connection and the curvature associated to the stretched rope equation. Following the prolongation structure analysis due to Wahlquist and Estabrook combined to Cartan-Ehresmann connection with structure group SL(3,R), we derive an interesting coupled system dubbed as the two-component stretched rope equation which physically and geometrically arises from the curve motion flow in Euclidean space. 相似文献
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Mouna Ferchichi Erwann JeanneauBernard Fenet Faouzi MeganemUlrich Darbost Isabelle Bonnamour 《Tetrahedron letters》2012,53(32):4047-4050
The synthesis of a series of six new per-substituted p-tert-butylcalix[9]arenes derivatives has been achieved. Functions such as ester, nitrile, or carbonate have been grafted on the phenolic oxygens of calix[9]arene: p-tert-butylcalix[9]arene nona-ethyl acetate, p-tert-butylcalix[9]arene nona-carboxylic acid, p-tert-butylcalix[9]arene nona-cyanopropyloxy, p-tert-butylcalix[9]arene nona-tert-butoxycarbonyle, p-tert-butylcalix[9]arene nona-acetyl, and p-tert-butylcalix[9]arene nona-trifluoroacetyl have been obtained in good yields (from 48% to 78%) and fully characterized. The X-ray structures of p-tert-butylcalix[9]arene nona-tert-butoxycarbonyl and p-tert-butylcalix[9]arene nona-ethyl acetate have been determined. A dynamic NMR study has revealed the high conformational mobility of such structures, even at low temperature. 相似文献
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Kheiria Hcini Abir Bahi Monia Bendhifi Zarroug Mouna Ben Farhat Antonio Abel Lozano-Prez Jos Luis Cenis María Quílez Sondes Stambouli-Essassi Maria Jos Jordn 《Molecules (Basel, Switzerland)》2022,27(24)
During the last decade there has been growing interest in the formulation of new cosmetic, food and pharmaceutical products containing natural compounds with antioxidant activity and other beneficial properties. Aromatic and medicinal plants have always been the major source of bioactive compounds, especially, wild thyme (Thymbra capitata L.), which has been used since ancient times for its valuable health benefits that could be attributed to the richness of polyphenolic compounds. This study was undertaken with the following aims: to estimate the total polyphenolic content (TPC); to evaluate the antioxidant activity; to identify and quantify the phenolic compounds of post-distilled residues of Tunisian thyme, and their contribution to the antioxidant activity. The TPC, as determined by the Folin–Ciocalteu method, was found to reach the values of 126.7 and 107.84 mg gallic acid equivalent/g plant dry weight (mg GAE/g PDW). The antioxidant activity, which is assessed by DPPH and FRAP assays, reached the values of 42.97–45.64 μg/mL and 42.22–50.21 mMFe2+/mg PDW, respectively. HPLC analysis revealed the presence of fourteen polyphenolic compounds, of which diosmin and rosmarinic acid were found to be the most abundant (24.26 to 33.80 and 22.0.1 to 26.29 mg/g PDW, respectively). An important correlation was found between the antioxidant activity and several identified phenolic compounds (p < 0.05). The findings revealed that thyme post-distilled residues have an effective natural antioxidant potential due to their high concentration of bioactive molecules, and they appear to be useful in the pharmaceutical, cosmetic, and food industries, with beneficial effects on human health. Therefore, supplementing a balanced diet with herbs may have beneficial health effects. 相似文献