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31.
The hazard and inconvenience of storing and handling concentrated hydrogen peroxide can be avoided by using instead the solid complex which 1,4-diazabicyclo[2.2.2] octane forms with hydrogen peroxide, it reacts with trialkylchlorosilanes to give bis(trialkylsilyl) peroxides in good yield. 相似文献
32.
Fumariflorine (, the only known alkaloidal -(β-dimethylaminoethyl)benzoic acid, has been isolated as its ethyl ester from Lam. (Fumariaceae). Since alkaloids – are also present in the plant, it is probable that the biogenetic sequence for the catabolism of the lactonic phthalideisoquinolines involves initial quatermination to an N-metho salt, Hofmann elimination, and oxidative cleavage of the resulting olefin to supply a substituted -(β-dimethylaminoethyl)benzoic acid. 相似文献
33.
Fazal Rahim Muhammad Ali Shifa Ullah Umer Rashid Hayat Ullah Muhammad Taha Muhammad Tariq Javed Wajid Rehman Aftab Ahmad Khan Obaid Ur Rahman Abid Muhammad Bilal 《中国化学快报》2016,27(5):693-697
Bis-thiobarbiturate derivatives 1–15 have been synthesized, characterized by1 HNMR and EI-MS and screened for urease inhibition. All compounds showed various degree of urease inhibitory activity with IC_(50) values ranging 7.45 0.12 74.24 0.81 mmol/L while the standard thiourea behaved normally(IC_(50) = 21.10 0.12). Compounds 1(IC_(50) = 7.45 0.12 μmol/L), 9(IC_(50) = 18.17 1.03 μmol/L) and 13(IC_(50) = 8.61 0.45 μmol/L) showed excellent urease inhibitory activity in the series. Molecular modeling studies were performed to understand the binding site with the bimetallic nickel center of the enzyme.Structure-activity relationship has also been established for these compounds. This study identified bisthiobarbiturate as a novel class of urease inhibitors. 相似文献
34.
Qureshi Haleema Sadia Ullah Shakir Ghafoor Fazal 《Journal of Russian Laser Research》2021,42(5):501-511
Journal of Russian Laser Research - Bipartite quantum entanglement has numerous practical applications in quantum computation and communication. Here, we study the temporal evolution of bipartite... 相似文献
35.
Hina Fazal Bilal Haider Abbasi Nisar Ahmad 《Applied biochemistry and biotechnology》2014,174(6):2086-2095
Adventitious root cultures of Prunella vulgaris L. were established in shaking flask system for the production of biomass and secondary metabolites. Adventitious root cultures were induced from callus cultures obtained from leaf explants on solid Murashige and Skoog (MS) medium containing combination of 6-benzyladenine (BA; 1.0 mg l?1) and naphthalene acetic acid (NAA; 1.5 mg l?1). Thereafter, 0.49 g inoculum was transferred to liquid MS medium supplemented with different concentrations of NAA (0.5–2.0 mg l?1). Growth kinetics of adventitious roots was recorded with an interval of 7 days for 49 days period. Highest biomass accumulation (2.13 g/l) was observed in liquid medium containing 1.0 mg l?1 NAA after 21 days of inoculation. However, other concentrations of NAA also showed similar accumulation pattern but the biomass gradually decreases after 49 days of inoculation. Adventitious roots were collected and dried for investigation of total phenolics (TP), total flavonoids (TF), and antioxidant activities. Higher TPC (0.995 GAE mg/g-DRB) and TFC (6.615 RE mg/g-DRB) were observed in 0.5 mg l?1 NAA treated cultures. In contrast, higher antioxidant activity (83.53 %) was observed 1.5 mg l?1 NAA treated cultures. These results are helpful in up scaling of root cultures into bioreactor for secondary metabolites production. 相似文献
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37.
Yan Y Wang J Zhang L Yang JY Fazal IM Ahmed N Shamee B Willner AE Birnbaum K Dolinar S 《Optics letters》2011,36(21):4269-4271
We propose a fiber coupler consisting of a central ring and four external cores to generate up to ten orbital angular momentum (OAM) modes. Four coherent input lights are launched into the external cores and then coupled into the central ring waveguide to generate OAM modes. By changing the size of the external cores, one can selectively excite a high-order OAM mode. The quality of the generated OAM modes can be enhanced by adjusting the polarization state and the phase of input lights. We show the generation of OAM modes with odd charge numbers of -9 to +9 (i.e., 10 modes totally) with mode purity of >99% using <2?mm long fiber. This fiber coupler design can be extended to enable all-fiber spatial-mode (de)multiplexing. 相似文献
38.
A theoretical investigation has been carried out for electromagnetic waves scattering from a perfect electromagnetic conductor (PEMC) sphere which is placed in chiral media. The formulation of the problem is realized by expanding the incident as well as the scattered electromagnetic fields in terms of left circularly polarized (LCP) and right circularly polarized (RCP) waves. By applying the boundary conditions at the chiral-PEMC interface, eight simultaneous equations are generated, which yield the scattering coefficients associated with the Left and Right electromagnetic waves. The relative contribution of Co-polarized and Cross-polarized components of fields to the calculations of scattering cross-section is presented. The effect of admittance parameter and the effect of chirality parameter in cases of lossless, lossy permittivity and lossy permeability on Co and Cross components of scattering cross sections are observed. The results are also compared with available published literatures which are in good agreement. 相似文献
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Md Alim Uddin Haojie Yu Li Wang Kaleem-ur-Rahman Naveed Fazal Haq Bilal Ul Amin Sahid Mehmood Ahsan Nazir Yusheng Xing Di Shen 《Journal of polymer science. Part A, Polymer chemistry》2020,58(14):1924-1948
The EPR technique is commonly used for the detection and characterization of paramagnetic centers in chemical science. This method can provides a lot of information, such as identity, structure, dynamics, interaction, orientation, glass transition temperature, adsorption behavior, functionality, phase behavior, nano-inhomogeneities, and conformation of the free-radical portion of the polymer chain. Most polymers intrinsically possess diamagnetic properties, so in order to study polymers with EPR, paramagnetic centers need to be incorporated into the polymer systems. Spin labeling and spin probing are main methods of covalently attaching paramagnetic centers to polymer chains or embedding them in polymer matrices through non-covalent interactions, respectively. Spin labeling and spin probing techniques for polymers and polymer systems (especially with nitroxide radicals) have also been studied, which have a profound impact on polymer science. This review focuses on the continuous wave EPR technique and introduces the recent advances in spin labeled polymers and spin probed polymer systems in EPR research. 相似文献