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61.
Hossein Naeimi Khadijeh Rabiei Fariba Salimi 《Phosphorus, sulfur, and silicon and the related elements》2013,188(9):2351-2357
A simple, efficient, and cost-effective method has been developed for the synthesis of N,N′-bis(2-hydroxybenzylidene)-1,1-diaminoalkanes through one-pot, three-component reaction of salicylaldehyde, aliphatic aldehydes, and ammonium nitrate in the presence of a base under solvent-free conditions at room temperature. 相似文献
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A multiwall carbon nanotube modified electrode prepared by incorporating multiwall carbon nanotubes in the electrode of a sensor and naphthol green as a homogeneous mediator was used as a voltammetric sensor for the determination of N‐actylcysteine(N‐AC) in the presence of trypto-phan(Trp). The voltammograms of differential pulse voltammetry of N‐AC in a mixture with Trp were separated from each other by a potential difference of 200 mV, which allowed the determina-tion of both N‐AC and Trp simultaneously. Under the optimum conditions, the electrocatalytic cur-rents increased linearly with N‐AC concentration in the range of 0.25–400 μmol/L(two linear seg-ments with different slopes). The detection limit for N‐AC was 0.08 μmol/L. The kinetic parameters of the system were determined using electrochemical methods. The method was applied for the determination of N‐AC in drug and urine samples. 相似文献
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Hossein A. Oskooie Negar M. Javadi Khadijeh Bakhtiari Fatemeh F. Bamoharram 《合成通讯》2013,43(17):2864-2869
Condensation of a variety of β-dicarbonyl compounds with primary and secondary amines carried out in the presence of catalytic amounts of K7[PW11CoO40]. From this reaction N-substituted β-enamino esters and ketones were obtained in high yields. 相似文献
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Khadijeh Rajabi D. J. Douglas 《Journal of the American Society for Mass Spectrometry》2013,24(6):907-916
The effects of binding two small-molecule inhibitors to Agrobacterium sp. strain ATCC 21400 (Abg) β-glucosidase on the conformations and stability of gas-phase ions of Abg have been investigated. Biotin-iminosugar conjugate (BIC) binds noncovalently to Abg while 2,4-dinitro-2-deoxy-2-fluoro-β-d-glucopyranoside (2FG-DNP) binds covalently with loss of DNP. In solution, Abg is a dimer. Mass spectra show predominantly dimer ions, provided care is taken to avoid dissociation of dimers in solution and dimer ions in the ion sampling interface. When excess inhibitor, either covalent or noncovalent, is added to solutions of Abg, mass spectra show peaks almost entirely from 2:2 inhibitor-enzyme dimer complexes. Tandem mass spectrometry experiments show similar dissociation channels for the apo-enzyme and 2FG-enzyme dimers. The +21 dimer produces +10 and +11 monomers. The internal energy required to dissociate the +21 2FG-enzyme to its monomers (767?±?30 eV) is about 36 eV higher than that for the apo-enzyme dimer (731?±?6 eV), reflecting the stabilization of the free enzyme dimer by the 2FG inhibitor. The primary dissociation channels for the noncovalent BIC-enzyme dimer are loss of neutral and charged BIC. The internal energy required to induce loss of BIC is 482?±?8 eV, considerably less than that required to dissociate the dimers. For a given charge state, ions of the covalent and noncovalent complexes have about 15 % and 25 % lower cross sections, respectively, compared with the apo-enzyme. Thus, binding the inhibitors causes the gas-phase protein to adopt more compact conformations. Noncovalent binding surprisingly produces the greatest change in protein ion conformation, despite the weaker inhibitor binding. Figure
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Majid M. Heravi Shima Taheri Khadijeh Bakhtiari Hossein A. Oskooie 《Monatshefte für Chemie / Chemical Monthly》2006,12(2):1075-1078
Cupric sulfate pentahydrate was found to be an efficient catalyst for the protection of aldehydes as 1,1-diacetates in high
yields in a solvent-free system at room temperature. Ketones are not affected under these reaction conditions. 相似文献
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A mild and efficient method for preparation of novel 2,2-dichloro-1,3-diarylaziridines from Schiff base compounds in the presence of Ar-cetyl-N,N,N-trimethyl ammonium bromide(CTAB) as phase transfer catalyst has been described.The reaction is dramatically enhanced in the presence of quaternary ammonium salt.The corresponding products have been obtained in excellent yields,high purity and short reaction times. 相似文献
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Atomic force microscopy is applied to measure intermolecular forces and mechanical properties of materials, nano-particle
manipulation, surface scanning and imaging with atomic accuracy in the nano-world. During nano-manipulation process, contact
forces cause indentation in contact area between nano-particle and tip/substrate which is considerable at nano-scale and affects
the nano-manipulation process. Several nano-contact mechanics models such as Hertz, Derjaguin–Muller–Toporov (DMT), Johnson–Kendall–Roberts–Sperling
(JKRS), Burnham–Colton–Pollock (BCP), Maugis–Dugdale (MD), Carpick–Ogletree–Salmeron (COS), Pietrement–Troyon (PT), and Sun
et al. have been applied as the continuum mechanics approaches at nano-scale. In this article, indentation depth and contact
radius between tip and substrate with nano-particle for both spherical and conical tip shape during nano-manipulation process
are analyzed and compared by applying theoretical, semiempirical, and empirical nano-contact mechanics models. The effects
of adhesion force, as the main contrast point in different nano-contact mechanics models, on nano-manipulation analysis is
investigated for different contact radius, and the critical point is discussed for mentioned models. 相似文献