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101.
Colorimetric and Spectrofluorimetric Methods for the Determination of Melatonin in Tablets and Serum
Abstract Two sensitive and accurate colorimetric and spectrofluonmetric methods, are presented for the determination of melatonin in tablets and serum. The first method utilizes the reactions of p-dimethylaminobenzaldehyde in hydrochloric acid (van Urk reagent)-ferric chloride in sulphuric acid (Salkowski reagent) mixture. The blue color of the resulting reaction product is measured at 630 nm. The second method is based on the reaction of melatonin with o-phthalaldehyde in acid medium which yields highly fluorescent condensation product that is measured at 465 nm as emission wavelength, using excitation wavelength at 355 nm. No interference was observed from tableting additives, and the applicability of the methods was examined by analysing tablets containing melatonin (single and combined with pyridoxine). Mean percentage recoveries from tablets were found to be 99.9+0.31 for single and 100.5+0.15 for combined tablets using colorimetric method, while by applying spectrofluorimetric method the recoveries were found to be 100.610.41 for single and 100.2+0.39 for combined tablets. Furthermore, the proposed methods were extended to the in-vitro determination of melatonin in serum. The detection limits are 0.27 ug ml?1 for colorimetric method and 0.00035 ug ml?1 for spectrofluorimetric method. 相似文献
102.
Aequationes mathematicae - We introduce a generalized orthogonality relation in real normed linear spaces via norm derivatives. The relation between this concept and other types of orthogonalities... 相似文献
103.
Wen Chen Olivier Maurel Christian La Borderie Thierry Reess Antoine De Ferron Mohammed Matallah Gilles Pijaudier-Cabot Antoine Jacques Frank Rey-Bethbeder 《Heat and Mass Transfer》2014,50(5):673-684
The objective of this study is to simulate the propagation of the shock wave in water due to an explosion. The study is part of a global research program on the development of an alternative stimulation technique to conventional hydraulic fracturing in tight gas reservoirs aimed at inducing a distributed state of microcracking of rocks instead of localized fracture. We consider the possibility of increasing the permeability of rocks with dynamic blasts. The blast is a shock wave generated in water by pulsed arc electrohydraulic discharges. The amplitude of these shock waves is prescribed by the electrohydraulic discharges which generate high pressures of several kilobars within microseconds. A simplified method has been used to simulate the injected electrical energy as augmentation of enthalpy in water locally. The finite element code EUROPLEXUS is used to perform fluid fast dynamic computation. The predicted pressure is consistent with the experimental results. In addition, shock wave propagation characteristics predicted with simulation can be valuable reference for design of underwater structural elements and engineering of underwater explosion. 相似文献
104.
Basma H. Amin Mohamed I. Abou-Dobara Mostafa A. Diab Essam A. Gomaa Mohammed A. El-Mogazy Adel Z. El-Sonbati Mohamed S. EL-Ghareib Mostafa A. Hussien Hanaa M. Salama 《应用有机金属化学》2020,34(8):e5689
A novel series of mixed-ligand complexes of 5,5′-{(1E,1E′)-1,4-phenelynebis(diazene-2,1-diyl)}bis(quinolin-8-ol) (H2L1) as a primary ligand and 4-aminoantipyrine(L2) as a secondary ligand with Mn(II) ion were prepared using two general formulae: [Mn2(H2L1)2(L2)2X4].4Cl (X = OH2( 1 ), ONO2−( 2 ), Cl=nil; OAc( 3 ), Cl = nil) and [Mn2(H2L1)(L2)2(O2SO2)2]( 4 ). Free ligands and their complexes were characterized. Electronic absorption spectra of the mixed-ligand complexes indicate a distorted octahedral geometry around the central metal ion, and the anions X− are in the axial positions for all compounds. The ligands behave in a neutral bidentate manner, through nitrogen atoms and oxygen atoms of the carbonyl group (L2), whereas H2L1 coordinated through nitrogen and OH groups as a neutral bidentate ligand. All complexes do not contain coordinated water molecules, but complex ( 1 ) contains four water molecules. The water molecules are removed in a single step. The complexes exhibited magnetic susceptibility corresponding to five unpaired electrons. The antimicrobial activity of the Mn(II) mixed-ligand complexes ( 1–4 ) against two gram-positive bacteria, three local gram-negative bacteria, and three fungi species was tested. Mn(II) mixed-ligand complex ( 2 ) exhibited significant antibacterial activity against Bacillus cereus, Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas sp. Mixed-ligand complex ( 2 ) exhibited a high potential cytotoxicity against the growth of human lung cancer cells. 相似文献
105.
Samira Benmouloud Rachid Echarghaoui Si. Mohammed Sbaï 《Journal of Mathematical Analysis and Applications》2012,396(1):375-385
In this paper, by using the Lusternik–Schnirelmann category, we obtain a multiplicity result for a quasilinear elliptic system with both concave and convex nonlinearities and critical growth terms in bounded domains. 相似文献
106.
Dr. Mohammed Tariq Dr. Daniel Salavera Prof. Alberto Coronas Prof. Luis P. N. Rebelo Prof. Jose N. Canongia Lopes 《Chemphyschem》2013,14(9):1956-1968
In this work the applicability of four of the most commonly used viscosity mixing rules to [ionic liquid (IL)+molecular solvent (MS)] systems is assessed. More than one hundred (IL+MS) binary mixtures were selected from the literature to test the viscosity mixing rules proposed by 1) Hind (Hi), 2) Grunberg and Nissan (G–N), 3) Herric (He) and 4) Katti and Chaudhri (K–C). The analyses were performed by estimating the average (absolute or relative) deviations, AADs and ARDs, between the available experimental data and the predicted ideal mixture viscosity values obtained by means of each rule. The interaction terms corresponding to the adjustable parameters inherent to each rule were also calculated and their trends discussed. 相似文献
107.
108.
Abdel-Kader Maged Saad Alam Prawez Alqarni Mohammed Hamed Salkini Mohamad Ayman 《平面色谱法杂志一现代薄层色谱法》2017,30(3):211-215
JPC – Journal of Planar Chromatography – Modern TLC - A novel, simple, and sensitive high-performance thin-layer chromatography (HPTLC) method has been successfully developed and... 相似文献
109.
Mohamed Laabd Lahoucine Atourki Hafsa Chafai Mohammed Bazzaoui Maria Elamine 《Journal of Dispersion Science and Technology》2017,38(9):1227-1233
This study sheds light on the removal of humic acid by-products (trimellitic and pyromellitic acids; TMA and PMA, respectively) from aqueous solution using conducting polypyrrole (PPy) as an effective adsorbent. The effects of experimental factors including contact time, solution pH, initial concentration, adsorbent dose, and temperature were systematically investigated. The pseudo-second-order kinetic model provides the best correlation with adsorption experimental data. The equilibrium adsorption was well described by the Langmuir model with maximum mono-layer adsorption capacities of 47.62 and 71.43?mg?g?1 for TMA and PMA, respectively. The analysis of thermodynamic parameters indicated that the adsorption process was spontaneous and endothermic in nature. In addition, we investigated the adsorption mechanism using the density functional theory (DFT) calculations. The TMA and PMA were physisorbed on the PPy surface through the formation of hydrogen bonds between carboxylic groups of adsorbate molecules and the amino group of the adsorbent. The calculated theoretical data were in good agreement with experiments. 相似文献
110.
Khalid Bouras Abdelmonaim El Kaddouri Jawad H’michane Mohammed Moussa 《Rendiconti del Circolo Matematico di Palermo》2012,61(3):355-360
We characterize Banach lattices on which each positive operators is b-weakly compact and we derive some characterizations of KB-spaces. 相似文献