排序方式: 共有189条查询结果,搜索用时 15 毫秒
91.
Yousri D. A. AbdelAty Amr M. Said Lobna A. Elwakil A. S. Maundy Brent Radwan Ahmed G. 《Nonlinear dynamics》2019,95(3):2491-2542
Nonlinear Dynamics - Fractional-order chaotic systems (FOCS) parameter identification is an essential issue in chaos control and synchronization process. In this paper, different recent... 相似文献
92.
Kitova EN El-Hawiet A Schnier PD Klassen JS 《Journal of the American Society for Mass Spectrometry》2012,23(3):431-441
The association-dissociation of noncovalent interactions between protein and ligands, such as other proteins, carbohydrates,
lipids, DNA, or small molecules, are critical events in many biological processes. The discovery and characterization of these
interactions is essential to a complete understanding of biochemical reactions and pathways and to the design of novel therapeutic
agents that may be used to treat a variety of diseases and infections. Over the last 20 y, electrospray ionization mass spectrometry
(ESI-MS) has emerged as a versatile tool for the identification and quantification of protein–ligand interactions in vitro.
Here, we describe the implementation of the direct ESI-MS assay for the determination of protein–ligand binding stoichiometry
and affinity. Additionally, we outline common sources of error encountered with these measurements and various strategies
to overcome them. Finally, we comment on some of the outstanding challenges associated with the implementation of the assay
and highlight new areas where direct ESI-MS measurements are expected to make significant contributions in the future. 相似文献
93.
Omar M. Ali Abd El-Galil E. Amr Elsayed E. Mostafa 《Research on Chemical Intermediates》2014,40(4):1545-1556
A series of tetrazolomethylbenzo[d][1,2,3]triazole derivatives (2–14) have been synthesized and evaluated as antimicrobial agents from 1H-benzo[d][1,2,3]triazole (1) as starting material. The reaction of benzotriazole 1 with chloroacetonitrile afforded 2-(1H-benzo[d][1,2,3]-triazol-1-yl)acetonitrile 2, which was reacted with sodium azide to give tetrazole derivative 3. Esterification of benzotriazole 1 with ethyl bromoacetate in the presence of anhydrous potassium carbonate afforded ester 4, which was treated with hydrazine hydrate to afford the corresponding hydrazide 5. Reaction of 3 with 2,3,4,6-tetra-O-acetyl-α-d-glucopyranosyl bromide afforded the nitro-glycoside derivative 6, which was deacetylated using methanolic ammonia to deprotected nitroglycoside 7. The hydrazide 5 was reacted with 4,5,6,7-tetrachlorophthalic anhydride or 1,2,4,5-benzenetetracarboxylic dianhydride in refluxing glacial acetic acid to give the corresponding imides 8 and 9, respectively. Also, the hydrazide 5 was reacted with carbon disulphide in ethanol to give potassium salt 10, which was reacted with hydrazine hydrate to afford aminotriazole derivative 11. The latter compound was reacted with carbon disulphide to afford thiadiazole derivative 12, which was treated with 2,3,4,6-tetra-O-acetyl-α-d-glucopyranosyl bromide to give the thioglycoside derivative 13. Deacetylation of the thioglycoside 13 using methanolic ammonia solution at room temperature afforded the deprotected thioglycoside 14. The antimicrobial screening of some synthesized compounds showed that many of these compounds have good antimicrobial activities comparable to streptomycin and fusidic acid as reference drugs. 相似文献
94.
95.
H. S. Abd-Elghaffar M. A. El-Hashash S. F. Mohamed A. A. Ibrahim A. E. Amr M. A. Al-Omar E. S. Nossier 《Russian Journal of General Chemistry》2020,90(4):686-696
A new series of fused 1,3-indandione derivatives has been synthesized and evaluated for anti-proliferative activity. 2-Alkene-1,3-indandione derivatives have been used as the precursors of a number of tricyclic compounds. The latter have been tested for anti-proliferative activity. 相似文献
96.
Mohamed E. Mahmoud Amr A. Yakout Somia B. Ahmed Maher M. Osman 《International journal of environmental analytical chemistry》2013,93(14):1017-1031
A method is proposed and explored for speciation of Cr(III) and Cr(VI), selective extraction and preconcentration in various water samples based on dynamic and static techniques. Three newly designed alumina phases-physically adsorbed-2-pyridenecarboxyladehyde-thiosemicarbazone [Al-2PC-TSC (I–III)] were synthesised and characterised. Stability tests and application of [Al-2PC-TSC (I–III)] as inorganic ion exchangers and chelating solid sorbents for various metal ions were studied and evaluated. The distribution coefficient and separation factors of chromium species versus other interfering metal ions were determined to examine the incorporated selectivity into these alumina phases. Quantitative recovery of Cr(VI) was accomplished by [Al-2PC-TSC (I–III)] at pH = 1.0 while Cr(III) was found to be quantitatively recovered on these sorbents at pH = 7.0 with minimal or no interference between these two species under the studied buffering conditions. Selective solid phase speciation and preconcentration of Cr(III) and Cr(VI) in various real water samples were successfully performed and accomplished via a micro-column, with 200 as a preconcentration factor. Selective speciation of Cr(VI) and Cr(III) via preconcentration from seawater and industrial water samples by alumina phases in pH = 1 was found to give percentage recovery values of Cr(VI) in the range 93.5–97.3 ± 3.0–5.0% and 94.0–97.5 ± 3.0–4.0%, for seawater and industrial water samples, respectively. 相似文献
97.
This study is interested in the illustration of ab initio potential energy curves for Ba+Arn (n = 1–4) clusters. The electronic structures of these molecules are calculated using [Ba2+] and [Ar] non-empirical core pseudo-potentials complemented by the core polarisation operators for both atoms, which allow the consideration of core valence correlation effects. The structure and stabilities of Ba+Arn (n = 1–4) clusters are investigated. These molecules are treated as one-electron active system. Spectroscopic constants and vibrational energy levels have been derived from their potentials. The analysis of the geometric forms, basing on the potential energy curves and the spectroscopic constants, clearly shows the importance of rare gas induced dipole. We also show that the dipolar interactions can influence the coupling between atoms. 相似文献
98.
Othman Amr M. Ghobashy Mohamed Mohamady Abd El‐Sattar Nour E. A. 《Journal of Sol-Gel Science and Technology》2021,98(3):593-604
Journal of Sol-Gel Science and Technology - In this article, the first aerogels synthesis through cross-linked polyacrylamide (PAAm) hydrogel was reported through the use of gamma irradiation... 相似文献
99.
The use of carboxylated graphene oxide (CGO) in the removal of organic pollutants from aquatic life is a recent and significant issue. In this study, EDTA-functionalized magnetite-carboxylated graphene oxide nanocomposite (EDTA-MCGO) was first used for the adsorptive removal of p-phenylenediamine (PDA) from industrial wastewaters. Based on the great surface area of the magnetic nanocomposite and the huge number of carboxyl groups from CGO and EDTA, multiple interactions to adsorb PDA can be anticipated. The maximum adsorption capacity of EDTA-MCGO was 994.75?mg g?1 at pH 7.8 and this value was decreased to 94.7% after seven cycles. The adsorption process was spontaneous and fits the pseudo-second-order kinetic model. PDA strongly deposited on the EDTA-MCGO surface via different electrostatic interactions and hydrogen bonding. The PDA removal efficiency from different environmental wastewaters was 98.6?±?0.6%. All the results demonstrate that the EDTA-MCGO nanocomposite is a potential magnetic extractor of aromatic contaminants from aquatic life.GRAPHICAL ABSTRACT 相似文献
100.
Amr Elattar Dr. Wenhui Li Dr. Hiroo Suzuki Prof. Takashi Kambe Dr. Takeshi Nishikawa Prof. Aung Ko Ko Kyaw Prof. Yasuhiko Hayashi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(26):e202104316
Two-dimensional (2D) hybrid perovskites with novel functionalities and structural diversity are a perfect platform for emerging optoelectronic devices such as photodetectors, light-emitting diodes, and solar cells. Here, we demonstrate that excess concentration of Cesium bromide (CsBr) is key to the formation of easily exfoliated 2D Cs2Cu(Cl/Br)4 perovskite crystal. Furthermore, by employing this trick to 2D perovskite MA2Cu(Cl/Br)4 (MA=methylammonium), we achieve a phase-pure easily exfoliated 2D mixed-cation (MA/Cs)2Cu(Cl/Br)4 perovskite crystal, which exhibits reduced bandgap (1.53 eV) with ferromagnetic behavior and photovoltaic property. The resultant mixed-cation structured device reveals enhanced efficiency compared to all MA and all Cs counterparts. These findings demonstrate the importance of cation-engineering in developing innovative materials with novel properties. 相似文献