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排序方式: 共有343条查询结果,搜索用时 15 毫秒
1.
Mhaidat I. Taha Z. A. Al Momani W. Hijazi A. K. 《Russian Journal of General Chemistry》2019,89(12):2584-2590
Russian Journal of General Chemistry - Photoconductive acenaphthenequinone derivatives have been synthesized by a one-pot process of acenaphthenequinone with different aromatic hydrazides... 相似文献
2.
New ONS hydrazone ligand, 2-[(2-aminochromon-3-yl)methylidene]-N-phenylhydrazinecarbothioamide, HL , was synthesized and reacted with different salts of Cu (II) ion (OAc−, NO3−, SO42− and Cl−) in absence and presence of secondary ligands (L′); 8-hydroxyquinoline, 1,10-phenanthroline or SCN−; to form binary and ternary Cu(II)-chelates. The ligand and its Cu(II)-complexes were fully characterized by analytical, spectral, thermal, conductivity and magnetic susceptibility measurements. The metal chelates showed octahedral, square planar and /or distorted tetraherdal arrangements. Coats–Redfern equations used to calculate the kinetic parameters of the thermal decomposition stages (Ea, A, ΔH, ΔS and ΔG). The compounds exhibit luminescence property; promising interesting potential applications as photoactive materials. Lippert–Mataga, Bakhshiev, Kawski–Chamma–Viallet and microscopic solvent polarity parameter and ETN correlation methods were applied on the solvatochromic shifts of emission spectra to evaluate the ground (μg) and excited (μe) states dipole moments. Excited state dipole moment is larger than the ground state which may be attributed to π-π* transition. The coordinating anions play an important role on the position and intensity of emission band. The ligand and its metal complexes showed antimicrobial activity towards Gram–positive bacteria, Gram–negative bacteria, yeast and fungus. The molecular structural parameters of HL and its Cu(II)- complexes have been calculated on the basis of DFT engaged in the Gaussian 09 program at the B3LYP/6-31G(d,p) level; the theoretical data are correlated with the experimental data. 相似文献
3.
Luciferin‐Regenerating Enzyme Mediates Firefly Luciferase Activation Through Direct Effects of D‐Cysteine on Luciferase Structure and Activity 下载免费PDF全文
Roohullah Hemmati Saman Hosseinkhani Reza H. Sajedi Taha Azad Amin Tashakor Nuredin Bakhtiari Farangis Ataei 《Photochemistry and photobiology》2015,91(4):828-836
Luciferin‐regenerating enzyme (LRE) contributes to in vitro recycling of D‐luciferin. In this study, reinvestigation of the luciferase‐based LRE assay is reported. Here, using quick change site‐directed mutagenesis seven T‐LRE (Lampyris turkestanicusLRE) mutants were constructed and the most functional mutant of T‐LRE (T69R) was selected for this research and the effects of D‐ and L‐cysteine on T69R T‐LRE‐luciferase‐coupled assay are examined. Our results demonstrate that bioluminescent signal of T69R T‐LRE‐luciferase‐coupled assay increases and then reach equilibrium state in the presence of 5 mm D‐cysteine. In addition, results reveal that 5 mm D‐ and L‐cysteine in the absence of T69R T‐LRE cause a significant increase in bioluminescence intensity of luciferase over a long time as well as decrease in decay rate. Based on activity measurements, far‐UV CD analysis, ANS fluorescence and DLS (Dynamic light scattering) results, D‐cysteine increases the activity of luciferase due to weak redox potential, antiaggregatory effects, induction of changes in conformational structure and kinetics properties. In conclusion, in spite of previous reports on the effect of LRE on luciferase bioluminescent intensity, the majority of increase in luciferase light output and time‐course originate from the direct effects of D‐cysteine on structure and activity of firefly luciferase. 相似文献
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Taha M. A. Eldebss Ahmad M. Farag Adel Y. M. Shamy 《Journal of heterocyclic chemistry》2019,56(2):371-390
A series of new substituted benzimidazoles embedded with a variety of function groups has been synthesized from N‐methyl‐2‐bromoacetylbenzimidazole. The synthesized compounds were fully characterized, and their structures were elucidated based on elemental analysis, spectral data, and alternative synthetic pathways, whenever possible. Some of benzimidazole derivatives were tested as corrosion inhibitors. 相似文献
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Sara Taha Gelan Rafat Fatma Aboshosha Fotouh R. Mansour 《Journal of Analytical Chemistry》2017,72(2):239-242
A simple portable spectrophotometer was constructed and used to perform analytical experiments. The developed model uses available tools and materials such as light emitting diode lamps, compact discs, plastic and cardboard boxes and a cell phone camera to build a design that illustrates the major components of spectrophotometers. The spectra of serial concentrations of KMnO4 (50?600 μM) were recorded and the values of absorbance were extracted at λmax to build the calibration curve. A linear relationship between the concentration and absorbance was obtained with the coefficient of determination 0.994. The model was also utilized to study the spectra of KMnO4, phenolphthalein and bromothymol blue in comparison with a Shimadzu UV-1800 spectrophotometer as a reference instrument. In spite of the differences in the observed spectra, the recorded λmax were almost identical to those measured by the developed model. The model was successfully used to determine the concentration of sodium alendronate through ligand-exchange complexation with ferric salicylate. 相似文献
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Y. M. Khawassek A. M. Masoud M. H. Taha A. E. M. Hussein 《Journal of Radioanalytical and Nuclear Chemistry》2018,315(3):493-502
The present work deals with the adsorption of uranium from a nitric acid waste solution using the cation exchange resin Amberjet 1200 H (AHR) . Batch experiments were performed in order to assess the performance of AHR in uranium adsorption. The influences of pH, contact time, initial uranium concentration and temperature have been enhanced. The physical parameters including the adsorption kinetics, the isotherm models and the thermodynamic data have also been determined to determine the nature of the uranium adsorption by AHR. The studied resin has been agreed with both the pseudo second order reaction and Langmuir isotherm. 相似文献
10.
The consecutive k-out-of-r-from-n: F system was generalized to multi-state case. This system consists of n linearly ordered components which are at state below j if and only if at least kj components out of any r consecutive are in state below j. In this paper we suggest bounds of increasing multi-state consecutive-k-out-of-r-from-n: F system (k1 ? k2 ? ? ? kM) by applying second order Boole–Bonferroni bounds and applying Hunter–Worsley upper bound. Also numerical results are given. The programs in V.B.6 of the algorithms are available upon request from the authors. 相似文献