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71.
Maissa Yacoub Salem Nahla Nour El Din Salama Lobna Mohammed Abd El Halim Laila El-Sayed Abdel Fattah 《Chromatographia》2009,70(7-8):1299-1302
Two sensitive and selective chromatographic methods were developed and validated for determination of veralipride in presence of its degradation products. Forced degradation studies were performed, using HCl, NaOH and 3% H2O2. The first method is based on thin-layer chromatographic separation of the intact drug spot from its degradation, followed by densitometric measurements. The second method is based on isocratic liquid chromatographic separation of the studied drug from its degradation on a reversed phase C18 column. The proposed LC method was utilized to investigate the kinetics of alkaline degradation process of the selected drug at different temperatures. 相似文献
72.
Laila Manni Kemel Jellouli Olfa Ghorbel-Bellaaj Rym Agrebi Anissa Haddar Alya Sellami-Kamoun Moncef Nasri 《Applied biochemistry and biotechnology》2010,160(8):2308-2321
The current increase in amount of shrimp wastes produced by the shrimp industry has led to the need in finding new methods
for shrimp wastes disposal. In this study, an extracellular organic solvent- and oxidant-stable metalloprotease was produced
by Bacillus cereus SV1. Maximum protease activity (5,900 U/mL) was obtained when the strain was grown in medium containing 40 g/L shrimp wastes
powder as a sole carbon source. The optimum pH, optimum temperature, pH stability, and thermal stability of the crude enzyme
preparation were pH 8.0, 60 °C, pH 6–9.5, and <55 °C, respectively. The crude protease was extremely stable toward several
organic solvents. No loss of activity was observed even after 60 days of incubation at 30 °C in the presence of 50% (v/v) dimethyl sulfoxide and ethyl ether; the enzyme retained more than 70% of its original activity in the presence of ethanol
and N,N-dimethylformamide. The protease showed high stability toward anionic (SDS) and non-ionic (Tween 80, Tween 20, and Triton
X-100) surfactants. Interestingly, the activity of the enzyme was significantly enhanced by oxidizing agents. In addition,
the enzyme showed excellent compatibility with some commercial liquid detergents. The protease of B. cereus SV1, produced under the optimal culture conditions, was tested for shrimp waste deproteinization in the preparation of chitin.
The protein removal with a ratio E/S of 20 was about 88%. The novelties of the SV1 protease include its high stability to organic solvents and surfactants. These
unique properties make it an ideal choice for application in detergent formulations and enzymatic peptide synthesis. In addition,
the enzyme may find potential applications in the deproteinization of shrimp wastes to produce chitin. 相似文献
73.
A novel approach to the electrochemical determination of heavy metals in tap water using anodic stripping voltammetry was developed using screen-printed electrodes modified with gold films. After optimisation of the experimental conditions, the screen-printed electrodes modified with gold films displayed excellent linear behaviour in the examined concentration range from 2 to 16 µg L-1 mercury and lead in 50 mM HCl with a detection limit of 1.5 µg L-1 and 0.5 µg L-1 for mercury and lead, respectively. In order to decrease the working range down to less than 1 µg L-1, a preconcentration step based on the use of magnetic particles modified with thiols was introduced into the protocol. Applying optimum binding conditions, the assay using screen-printed electrodes modified with gold films displayed excellent linear behaviour in the concentration range 0.1 to 0.8 µg L-1 in 50 mM HCl. The detection limit after a 120 s deposition time for mercury and lead were 0.08 µg L-1 and 0.02 µg L-1, respectively. The method has been applied to the determination of mercury and lead traces in tap water 相似文献
74.
A simple, accurate, precise, and sensitive kinetic spectrophotometric method for determination of befunolol hydrochloride is described. The method is based on the formation of a colored product with 4-chloro-7-nitro-2,1,3-benzoxadiazole (NBD-Cl) in methanol at 70 degrees C for 45 min. The red-colored product was measured at 523 nm. The optimization of various experimental conditions is described; Beer's law was obeyed in the range 15.25 x 10(-6) to 122.04 x 10(-6) M. The results obtained showed good recoveries (100.1 +/- 0.80%). Application of the proposed method to a pharmaceutical formulation was successfully achieved. The determination of befunolol hydrochloride by fixed time, fixed concentration, and rate constant methods was feasible with the calibration equation obtained. However, the fixed time method proved to be more applicable. 相似文献
75.
Laila H. Abdel‐Rahman Rafat M. El‐Khatib Shimaa M. Abdel‐Fatah H. Moustafa Ali M. Alsalme Ayman Nafady 《应用有机金属化学》2019,33(11)
In this study, three novel complexes comprising trivalent Cr (III), Fe (III) and Ru (III) with imine ligand derived from 2‐amino‐3‐hydroxypyridine and o‐vanillin (H2L) have been synthesized and characterized via wide range of spectroscopic and analytical tools such as 1H NMR and 13C NMR, infrared (IR) and UV–Vis spectrophotometry, conductivity and magnetic measurements. The obtained results along with DFT data confirmed a 1:1 (metal: ligand) stoichiometry with non‐planner geometries for the three complexes. The binding action and the docking study of the prepared metal‐complexes to calf thymus DNA was also studied by absorption spectra and viscosity technique, which revealed that the three complexes interact strongly with DNA through intercalative binding mode. Significantly, these metal‐imine complexes showed strong and efficient anti‐inflammatory and antimicrobial activities against various gram‐positive (Microccus luteus), gram‐negative (Escherichia coli and Serratia marcescence) bacteria, and three strains of fungus. Moreover, all complexes exhibited more potent cytotoxicity effect on the outgrowth of different types of carcinoma cells, including human colon (HCT‐116 cell line), breast (MCF‐7 cell line), and hepatic cellular (HepG‐2), than the clinically‐proven Vinblastine standard. 相似文献
76.
Bushra Nisar Syeda Laila Rubab Abdul Rauf Raza Sobia Tariq Ayesha Sultan Muhammad Nawaz Tahir 《Molecular diversity》2018,22(3):709-722
Novel and highly sensitive indole-based imines have been synthesized. Their synthesis has been compared employing a variety of protocols. Ultimately, a convenient, economical and high yielding set of conditions employing green chemistry have been designed for their synthesis. 相似文献
77.
Laila Omi Murtaza Imtiyaz Abdin Malik Zainul Ahmad Sayeed Khan Masood Shah 《平面色谱法杂志一现代薄层色谱法》2019,32(2):95-102
JPC – Journal of Planar Chromatography – Modern TLC - The present research work was undertaken to develop and validate a sensitive, fast, and reproducible high-performance thin-layer... 相似文献
78.
Sonochemical synthesis,structural inspection and semiconductor behavior of three new nano sized Cu(II), Co(II) and Ni(II) chelates based on tri‐dentate NOO imine ligand as precursors for metal oxides
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Laila H. Abdel Rahman Ahmed M. Abu‐Dief Rafat M. El‐Khatib Shimaa Mahdy Abdel‐Fatah A.M. Adam E.M.M. Ibrahim 《应用有机金属化学》2018,32(3)
Three novel nanosized Cu(II), Co(II) and Ni(II) complexes of imine ligand attained from the condensation of 2‐amino‐3‐hydroxypyridine and 3‐methoxysalicylaldehyde have been prepared and investigated using diverse chemical methods such as NMR, CHN analysis, conductance, IR, Spectral studies, TGA and magnetic moment measurements. The obtained data confirmed that the synthesized complexes have metal: ligand ratio of 1:1 and octahedral geometry for Co(II) and Ni(II) complexes. Interestingly, The complexes are used as precursors for producing CuO, Co2O3 and NiO nanoparticles by calcination at 500 °C and their structures were described by powder x‐ray and transmittance electron microscopy. Furthermore, to investigate the feasibility of using the synthesized materials for semiconductor based nanodevices, the electrical properties of the prepared imine complexes and their corresponding metal oxides were investigated by measuring the electrical conductivity over a temperature range 373‐593 K. The data confirm that the materials are semiconductor. The electrical conduction process in the complexes is governed by intermolecular and intramolecular transfer of the charge carriers. But, the conduction mechanism arises from the contribution of the phonon‐assisted small polaron hopping in NiO nanoparticles and charge carrier hopping in CuO and Co2O3 nanoparticles. The results indicate that the complexes under study are promising candidates for wide scale of organic based semiconducting devices. 相似文献
79.
80.
Machkour A Thallaj NK Benhamou L Lachkar M Mandon D 《Chemistry (Weinheim an der Bergstrasse, Germany)》2006,12(25):6660-6668
Coordination of FeCl3 to the title ligand yields a mononuclear iron(III) complex 1, which was characterized by spectroscopic techniques and X-ray diffraction. The ligand is (kappa3-N) tridentate and the metal, which lies in a pseudo-octahedral environment, is bound to a phenolate group from the catechol substituent. The dichloroiron(II) complex 2 was easily obtained by metalation of the ligand with FeCl2 and characterized by various spectroscopic techniques. In their cyclic voltammograms both 1 and 2 display the same reversible FeII/FeIII wave at E1/2=10 mV (vs. SCE). Reduction of compound 1 with Zn/Hg yields 2', which displays identical properties to 2. Taken together, these findings indicate that in spite of the different oxidation state of the metal in 2, no major geometrical/structural change is observed at the metal center with respect to 1. The reaction of 2 with dioxygen in the absence of organic substrates proceeds extremely rapidly and yields compound 3, which is a diiron(III) derivative whose X-ray crystal structure is also reported. The possibility of a radical-based mechanism is discussed. Compound 3 displays an unusual geometry: one iron(III) center is seven-coordinate, whereas the other lies in a square-pyramidal environment. The two iron atoms are bridged by the catecholato substituents. To the best of our knowledge, 3 is the first example of a seven-coordinate iron(III) derivative with tris(2-pyridylmethyl)amine ligands. 相似文献