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101.
Medhat Ibrahim Noha A. Saleh Ali Jameel Hameed Wael M. Elshemey Anwar A. Elsayed 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2010,75(2):702-709
Density functional theory (DFT) calculations have been carried out at the hybrid Becke 3-Lee–Yang–Parr; B3LYP/3-21G** level of theory to study two series of hydroxy-chalca-acetic acid-(4-pyrrolidin-1-yl-phenyl) ester [C60-C2H4N-(4-XCOCH2OH)C6H4] and hydroxy-chalcoacetic acid-[2-(2-hydroxy-acetylchalcanyl)-4-pyrrolidin-1-yl-phenyl] ester[C60-C2H4N-(3,4-XCOCH2OH)C6H4]. The X atom is O, S or Se for the two series. The vibrational spectra, physical, chemical, thermodynamics and Quantitative Structure Activity Relationship (QSAR) properties of the studied molecules are calculated and discussed. We have evaluated these molecules as HIV-1 protease inhibitors based on the hydrogenation interaction between the hydroxymethylcarbonyl (HMC) groups and the two aspartic acid of the HIV-1 protease active site. Results show that some of the investigated fullerene-based derivatives can be considered promising as HIV-1 protease inhibitors. 相似文献
102.
In this paper, data concerning the effect of pH on the morphology of Ag–TiO2 nanocomposite during photodeposition of Ag on TiO2 nanoparticles is reported. TiO2 nanoparticles prepared by sol–gel method were coated with Ag by photodeposition from an aqueous solution of AgNO3 at various pH levels ranging from 1 to 10 in a titania sol, under UV light. The as-prepared nanocomposite particles were
characterized by UV–vis absorption spectroscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD), and N2 adsorption/desorption method at liquid nitrogen temperature (−196 °C) from Brunauer–Emmett–Teller (BET) measurements. It
is shown that at a Ag loading of 1.25 wt.% on TiO2, a high-surface area nanocomposite morphology corresponding to an average of one Ag nanoparticle per titania nanoparticle
was achieved. The diameter of the titania crystallites/particles were in the range of 10–20 nm while the size of Ag particles
attached to the larger titania particles were 3 ± 1 nm as deduced from crystallite size by XRD and particle size by TEM. Ag
recovery by photo harvesting from the solution was nearly 100%. TEM micrographs revealed that Ag-coated TiO2 nanoparticles showed a sharp increase in the degree of agglomeration for nanocomposites prepared at basic pH values, with
a corresponding sharp decrease in BET surface area especially at pH > 9. The BET surface area of the Ag–TiO2 nanoparticles was nearly constant at around a value of 140 m2 g−1 at all pH from 1–8 with an anomalous maximum of 164 m2 g−1 when prepared from a sol at pH of 4, and a sharp decrease to 78 m2 g−1 at pH of 10. 相似文献
103.
Sadek KU Mekheimer RA Hameed AM Elnahas F Elnagdi MH 《Molecules (Basel, Switzerland)》2012,17(5):6011-6019
A one-pot and clean synthesis of 2-arylbenzothiazoles via the ambient temperature reaction of 2-aminothiophenols and aromatic aldehydes without catalyst in glycerol as a green solvent has been reported. 相似文献
104.
Bimetallic Cyclometalated Iridium(III) Diastereomers with Non‐Innocent Bridging Ligands for High‐Efficiency Phosphorescent OLEDs 下载免费PDF全文
Dr. Yonghao Zheng Dr. Andrei S. Batsanov Dr. Mark A. Fox Dr. Hameed A. Al‐Attar Khalid Abdullah Dr. Vygintas Jankus Prof. Martin R. Bryce Prof. Andrew P. Monkman 《Angewandte Chemie (International ed. in English)》2014,53(43):11616-11619
Two phosphorescent dinuclear iridium(III) diastereomers (ΛΔ/ΔΛ) and (ΛΛ/ΔΔ) are readily separated by making use of their different solubilities in hot hexane. The bridging diarylhydrazide ligand plays an important role in the electrochemistry and photophysics of the complexes. Organic light‐emitting devices (OLEDs) that use these complexes as the green‐emissive dopants in solution‐processable single‐active‐layer architectures feature electroluminescence efficiencies that are remarkably high for dinuclear metal complexes, achieving maximum values of 37 cd A?1, 14 lm W?1, and 11 % external quantum efficiency. 相似文献
105.
Muhammad Imran Abdul Hameed Shafiullah Rahman M. Hafizur Imdad Ali Talat Roome 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(11-12):729-735
AbstractTolbutamide is an oral anti-diabetic agent for the treatment of type 2 diabetic patients. Its lower absorption results in its inferior therapeutic efficacy. Nano-carrier systems have the subject of greater interests for enhancing efficacy of such drugs. Current study was designed to improve the tolbutamide therapeutic efficacy through its delivery in Gum Xanthan (GX) stabilized green gold nanoparticles (AuNPs). GX stabilized AuNPs were characterized for surface plasmon resonance (SPR), morphology, size, polydisoersity index (PDI) and zeta potential through UV spectrophotometer, atomic force microscope (AFM) and zetasizer respectively. They were used for loading tolbutamide and loaded nanoparticles were investigated for morphology, size, PDI, zeta potential and drug loading efficiency. FT-IR analysis was used for conforming GX functional groups involvement in AuNPs stabilization and drug-excepients interactions. Tolbutamide loaded in the synthesized nanoparticles was investigated for its insulin secretion potentials in isolated mice islets. Synthesized AuNPs were found in nano-size range with spherical morphology, increased surface negativity and loaded increased concentration of drug without changing its chemical nature. They markedly enhanced the tolbutamide insulin secretion potentials as compared to simple drug solution. Results confirm that the developed nano-carrier system is highly efficient in achieving higher therapeutic efficacy of drugs like tolbutamide. 相似文献
106.
Sudharshan Prabhu Rekha PD Chiu-Chung Young Asif Hameed Shih-Yao Lin Arun AB 《Applied biochemistry and biotechnology》2013,171(4):817-831
Zeaxanthin carotenoids are class of commercially important natural products and diverse biomolecules produced by plants and many microorganisms. Bacteria often produce a cocktail of polar and nonpolar carotenoids limiting their industrial applications. Marine members of the family Flavobacteriaceae are known to produce potential carotenoids such as astaxanthin and zeaxanthin. A few bacterial species have been reported for the predominant production zeaxanthin. Here, we report the molecular identification of the zeaxanthin as a major carotenoid produced by two novel bacteria (YUAB-SO-11 and YUAB-SO-45) isolated from sandy beaches of South West Coast of India and the effect of carbon sources on the production of zeaxanthin. The strains were identified based on the 16S rRNA gene sequencing as a member of genus Muricauda. The closest relatives of YUAB-SO-11 and YUAB-SO-45 were Muricauda aquimarina (JCM 11811T) (98.9 %) and Muricauda olearia (JCM 15563T) (99.2 %), respectively, indicating that both of these strains might represent a novel species. The highest level of zeaxanthin production was achieved (YUAB-SO-11, 1.20?±?0.11 mg g?1) and (YUAB-SO-45, 1.02?±?0.13 mg g?1) when cultivated in marine broth supplemented with 2 % NaCl (pH 7) and incubated at 30 °C. Addition of 0.1 M glutamic acid, an intermediate of citric acid cycle, enhanced the zeaxanthin production as 18 and 14 % by the strains YUAB-SO-11 and YUAB-SO-45 respectively. The zeaxanthin showed in vitro nitric oxide scavenging, inhibition of lipid peroxidation, and 2,2-diphenyl-1-picryl hydrazyl scavenging activities higher than the commercial zeaxanthin. The results of this study suggest that two novel strains YUAB-SO-11 and YUAB-SO-45 belonging to genus Muricauda produce zeaxanthin as a predominant carotenoid, and higher production of zeaxanthin was achieved on glutamic acid supplementation. The pigment showed good in vitro antioxidant activity, which can be exploited further for commercial applications. 相似文献
107.
Faesen AC Luna-Vargas MP Geurink PP Clerici M Merkx R van Dijk WJ Hameed DS El Oualid F Ovaa H Sixma TK 《Chemistry & biology》2011,18(12):1550-1561
Ubiquitin-specific proteases (USPs) are papain-like isopeptidases with variable inter- and intramolecular regulatory domains. To understand the effect of these domains on USP activity, we have analyzed the enzyme kinetics of 12 USPs in the presence and absence of modulators using synthetic reagents. This revealed variations of several orders of magnitude in both the catalytic turnover (kcat) and ubiquitin (Ub) binding (KM) between USPs. Further activity modulation by intramolecular domains affects both the kcat and KM, whereas the intermolecular activators UAF1 and GMPS mainly increase the kcat. Also, we provide the first comprehensive analysis comparing Ub chain preference. USPs can hydrolyze all linkages and show modest Ub-chain preferences, although some show a lack of activity toward linear di-Ub. This comprehensive kinetic analysis highlights the variability within the USP family. 相似文献
108.
In the present investigation we have presented the peristaltic flow of a linear Maxwell model through porous boundaries in
a porous medium. The governing non-dimensional partial differential are solved in wave frame by using regular perturbation
method and assumed form of solution. We have discussed the problem only for free pumping case. The effects of various physical
parameters involved in the problem have been investigated and shown graphically. 相似文献
109.
In this communication, we present novel nanofilled polymer composites prepared using a poly(l-lactic acid) (PLLA) matrix and amyloid fibers. Amyloid fibers are made from protein sources’ and share many of the same material properties as spider silk, but exist at significantly smaller length scales with diameters of 5–10 nm. This work highlights the potential use of amyloid fibers as nanofillers in the development of renewable polymeric materials with tuneable properties. Improvements in the glass transition temperature (Tg), elongation at break and Young’s modulus was measured, while the yield strength of the new materials was not seriously hampered. 相似文献
110.
We propose and analyze a novel (to the best of our knowledge) design of a polarization rotator (PR) based on silica photonic crystal fiber. The proposed design has a rectangular core region with a slanted sidewall. The simulation results are obtained using the full vectorial finite difference method as well as the full vectorial finite difference beam propagation method. The numerical results reveal that the suggested PR can provide a nearly 100% polarization conversion ratio with a device length of 3102 μm. 相似文献