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61.
62.
Nada M. Mostafa Mohamed L. Ashour Omayma A. Eldahshan 《Natural product research》2016,30(18):2093-2100
A novel biflavonoid [kaempferol (6→8″) apigenin] was isolated from the leaves of Jacaranda acutifolia. The structure was elucidated based on chemical evidence, 1D and 2D spectroscopic analyses as well as spectrometric techniques. The compound showed promising cytotoxic activity against breast cancer cell line MCF-7. The anticancer activity was explained via virtual docking of the isolated compound to the main sites in the human cyclin-dependent kinase2 (CDK2) crystal structure. 相似文献
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64.
Promising voltammetric sensors based on the modification of Pt and poly(3-methylthiophene) (PMT) electrodes with Pd nanoparticles were achieved for the determination of catecholamine neurotransmitters, ascorbic acid and acetaminophen. Electrochemistry of the indicated compounds was studied at these electrodes and interesting electrocatalytic effects were found. Furthermore, simple, easily prepared one electrochemical step Pd-modified Pt electrode (Pt/Pd) is reported for the first time. Cyclic voltammetry (CV) and chronocoulometry (CC) were used for the determination of the apparent diffusion coefficients in different electrolytes at these electrodes and the values are in the range from 10−4 to 10−5 cm2 s−1. Furthermore, it was found that the method of polymer formation had a substantial effect on the synergism between the polymer film and the loaded metal particles towards the oxidation of dopamine (DA) in different supporting electrolytes. This was confirmed by the CV, CC and EIS (electrochemical impedance spectroscopy) as well as SEM (Scanning Electron Microscopy) results. Pt and PMT electrodes modified with Pd nanoparticles showed excellent results for the simultaneous determination of tertiary and quaternary mixtures of the studied compounds. 相似文献
65.
Regioselective 1,3‐dipolar cycloaddition of nitrilimines (generated in situ from dehydrohalogenation of the corresponding hydrazonoyl halides by the action of triethylamine) with 4‐arylidene‐1‐aryl‐2‐phenyl‐1H‐imidazol‐5(4H)‐one 3 afforded the corresponding spiro[4,4]nona‐2,8‐dien‐6‐one 4 . The reaction was carried out in dry benzene under reflux temperature. Refluxing in acetic acid, 4a was converted to its respective N‐phenylpyrazole‐5‐carboxamide 8 . The structures of prepared compounds were established by elemental analyses and spectral data (IR, MS, 1H, and 13C NMR). © 2011 Wiley Periodicals, Inc. Heteroatom Chem 22:131–136, 2011; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.20666 相似文献
66.
A novel sensor of cysteine self-assembled monolayers over gold nanoparticles modified gold electrode has been constructed for the determination of epinephrine in presence of sodium dodecyl sulfate (Au/Au(nano)-CysSDS). Electrochemical investigation and characterization of the modified electrode are achieved using cyclic voltammetry, linear sweep voltammetry, and scanning electron microscopy. The Au/Au(nano)-CysSDS electrode current signal is remarkably stable via repeated cycles and long term stability, due to the strong Au-S bond, compared to the Au/Au(nano) electrode. The catalytic oxidation peak currents obtained from linear sweep voltammetry (LSV) increased linearly with increasing epinephrine concentrations in the range of 2 to 30 μmol L(-1) and 35 to 200 μmol L(-1) with correlation coefficients of 0.9981 and 0.9999 and a limit of detection of 0.294 nmol L(-1) and 1.49 nmol L(-1), respectively. The results showed that Au/Au(nano)-CysSDS can selectively determine epinephrine in the coexistence of a large amount of uric acid and glucose. In addition, a highly selective and simultaneous determination of tertiary mixture of ascorbic acid, epinephrine, and acetaminophen is explored at this modified electrode. Excellent recovery results were obtained for determination of epinephrine in spiked urine samples at the modified electrode. Au/Au(nano)-CysSDS can be used as a sensor with excellent reproducibility, sensitivity, and long term stability. 相似文献
67.
Taib N Aimé A Houmadi S Castano S Barthélémy P Laguerre M Bestel I 《Langmuir : the ACS journal of surfaces and colloids》2012,28(19):7452-7460
Nucleolipids are currently under investigation as vectors for oligonucleotides (ON) delivery thanks to their supramolecular organization properties and their ability to develop specific interactions (i.e., stacking and potential Watson and Crick hydrogen bonds) for lipoplexes formation. To investigate the factors that govern the interaction events at a molecular level and optimize nucleolipid chemical structures, physicochemical experiments (tensiometry, AFM, BAM, and ellipsometry) combined with molecular dynamics simulation were performed on a series of zwitterionic nucleolipids (PUPC, DPUPC, PAPC) featuring a phosphocholine chain (PC). After construction and initial equilibration, simulations of pure nucleolipid bilayers were run for 100 ns at constant temperature and pressure, and their properties were compared to experimental data and to natural dipalmitoylphosphatidylcholine (DPPC) bilayers. Nucleolipid-based membranes are significantly more ordered and compact than DPPC bilayers mainly due to the presence of many intermolecular interactions between nucleoside polar heads. The hydrophilic phosphocholine moieties connected to the 5' hydroxyls are located above the bilayers, penalizing nucleic bases accessibility for further interactions with ON. Hence, a neutral nucleolipid (PUOH) without hydrophilic phosphocholine was inserted in the membranes. Simulations and experimental analysis of nucleolipid membranes in interaction with a single strand RNA structure indicate that PUOH interacts with ON in the subphase. This study demonstrates that molecular modeling can be used to determine the interactions between oligonucleotide and nucleolipids. 相似文献
68.
Perišić-Janjić Nada U. Jevrić Lidija R. Bončić-Caričić Gordana A. Jovanović Bratislav Ž. 《平面色谱法杂志一现代薄层色谱法》2001,14(4):277-282
JPC – Journal of Planar Chromatography – Modern TLC - The chromatographic behavior of four groups of s-triazine derivatives (15 compounds) has been studied on aminoplast and cellulose... 相似文献
69.
Nasser R. El-Brollosy Mohamed F. Abdel-Megeed Afaf R. Genady 《Monatshefte für Chemie / Chemical Monthly》2001,14(1):1063-1073
A facile and efficient synthesis of a series of novel 1,2,4-triazolo[5,1-b]quinazolines is described. 2,3-Diaryl-2,3-dihydro-1H-1,2,4-triazolo[5,1-b]quinazolin-9-ones were obtained by reaction of 3-amino-2-arylamino-3H-quinazolin-4-ones with aromatic aldehydes as well as by ring closure of the corresponding anils. Treatment of 3-amino-2-arylamino-3H-quinazolin-4-ones with aromatic carboxylic acids afforded 2,3-diaryl-3H-1,2,4-triazolo[5,1-b]quinazolin-9-ones which could also be synthesized by dehydrogenation of the corresponding dihydro derivatives. Reaction of 3-amino-2-arylamino-3H-quinazolin-4-ones with diethyl malonate and acetylacetone gave 3-aryl-3,9-dihydro-9-oxo-1,2,4-triazolo[5,1-b]quinazolin-2-yl-acetic acid ethyl ester and 3-aryl-2-methyl-3H-1,2,4-triazolo[5,1-b]quinazolin-9-ones, respectively. The latter compounds were also prepared via reaction with acetic anhydride, whereas acetylation with acetic anhydride in the presence of pyridine afforded the acetyl derivatives. 相似文献
70.
Ahmed F. Saleh Mazin M. Elias Nada F. Tawfiq 《Journal of Radioanalytical and Nuclear Chemistry》2013,298(1):187-193
Precise determination of uranium concentration in human urine is quite important in assessment of occupational and public exposure to uranium. In the present work, a pulsed dye nitrogen laser-induced kinetic phosphorescence analysis (KPA) was used to determine uranium in urine of Iraqi phosphate mine and fertilizer plant workers and in the population living near the mining region. A total of 92 urine samples were collected from workers of the Akashat phosphate mine, the Al-Qaim fertilizer complex, and the Akashat residential region. Uranium concentration in urine of all samples ranged between 0.49 to 5.26 μg L?1 with a total average of 1.47 ± 0.01 μg L?1. For comparison, all samples were also analyzed using a completely different technique; the nuclear fission track analysis using CR-39 SSNTD. Both techniques were capable of such measurements, although not with an equal degree of uncertainty. KPA technique is found to be more suitable for analysis of urine samples having high concentrations of uranium. 相似文献