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141.
Ai Ito Takamasa Amaki Ayako Ishii Kazuo Fukuda Ryu Yamasaki Iwao Okamoto 《Tetrahedron letters》2018,59(45):3994-3998
Aromatic amides bearing 2-azulenyl group on the amide nitrogen were synthesized and their structures were investigated. The π-electron density of the N-aryl group was found to influence the cis-trans conformational preferences of these compounds in solution. X-ray crystallography revealed that the plane of the 2-azulenyl ring has a strong tendency to lie coplanar with the amide plane when the azulene group is located on the same side as the amide oxygen atom. 相似文献
142.
蛋白质蛋氨酸亚砜化是一种重要的氧化还原依赖的蛋白质翻译后修饰,不仅是氧化应激的重要标志物之一,也是一种蛋白质功能调控开关可影响活性氧信号转导,与一系列疾病尤其是神经退行性疾病的发生发展密切相关。 在许多生物体中,蛋氨酸亚砜还原酶是目前已经发现的唯一能将蛋白质蛋氨酸亚砜还原为蛋氨酸的物质,可以修复氧化损伤蛋白,恢复蛋白质功能,调控细胞氧还平衡,对相关疾病的治疗具有非常重要的意义。 本文重点介绍蛋氨酸亚砜和蛋氨酸亚砜还原酶的结构和催化机理,综述蛋氨酸亚砜和蛋氨酸亚砜还原酶荧光探针的部分研究进展,对该领域的研究前景进行展望。 相似文献
143.
The flocculation behavior of anionic and cationic latex dispersions induced by addition of ionic surfactants with different polarities (SDS and cetyltrimethylammonium bromide (CTAB)) have been evaluated by rheological measurements. It was found that in identical polar surfactant systems with particle surfaces of SDS + anionic lattices and CTAB + cationic lattices, a weak and reversible flocculation has been observed in a limited concentration region of surfactant, which was analyzed as a repletion flocculation induced by the volume-restriction effect of the surfactant micelles. On the other hand, in oppositely charged surfactant systems (SDS + cationic lattices and CTAB + anionic lattices), the particles were flocculated strongly in a low surfactant concentration region, which will be based on the charge neutralization and hydrophobic effects from the adsorbed surfactant molecules. After the particles stabilized by the electrostatic repulsion of adsorbed surfactant layers, the system viscosity shows a weak maximum again in a limited concentration region. This weak maximum was influenced by the shear rate and has a complete reversible character, which means that this weak flocculation will be due to the depletion effect from the free micelles after saturated adsorption. 相似文献
144.
Sarah E. Walker Dr. James A. Jordan‐Hore Dr. David G. Johnson Prof. Dr. Stuart A. Macgregor Dr. Ai‐Lan Lee 《Angewandte Chemie (International ed. in English)》2014,53(50):13876-13879
A direct Pd‐catalyzed C? H functionalization of benzoquinone (BQ) can be controlled to give either mono‐ or disubstituted BQ, including the installation of two different groups in a one‐pot procedure. BQ can now be directly functionalized with aryl, heteroaryl, cycloalkyl, and cycloalkene groups and, moreover, the reaction is conducted in environmentally benign water or acetone as solvents. 相似文献
145.
Synthesis,Characterization, and Photoluminescence Properties of Silver(I) Metal‐Organic Polymers with Nanochannels Based on 2‐Sulfoterephthalic Acid and Di(pyridin‐2‐yl)amine Ligands 下载免费PDF全文
Hui Huang Mahmood Payehghadr Jie Wang Hong‐Ping Xiao Ai‐Yin Wang Xin‐Hua Li Ali Morsali 《Helvetica chimica acta》2014,97(3):345-354
Two new silver(I) 3D coordination polymers, namely [Ag3(2‐stp)(dpa)]n ( 1 ) and {[Ag2(2‐stp)(H2O)]?Hdpa}n ( 2 ) (2‐NaH2stp=sodium 2,5‐dicarboxysulfonate, dpa=di(pyridine‐2‐yl)amine) were synthesized. The complexes were characterized by elemental analysis, FT‐IR spectra, thermogravimetric analyses (TGA), and single‐crystal X‐ray diffraction. In complex 1 , three neighboring Ag ions are bridged by N‐ and O‐atom, forming a 3D coordination network. The molecular structure of 2 is cation? anion species, forming 3D host? guest supramolecular network with the [Hdpa]+ cations encapsulated in the nanochannels. The photoluminescence properties of the complexes were also investigated in the solid state at room temperature. 相似文献
146.
147.
Three new isoprenylated 2‐arylbenzofurans, artopetelins A–C ( 1 – 3 ), were isolated as minor constituents from the EtOH extract of the root barks of Artocarpus petelotii Gagnep . Their structures were elucidated by spectroscopic methods, including HR‐EI‐MS and 2D‐NMR techniques. 相似文献
148.
Three octacyanometallate‐based hetero‐bimetallic complexes, [Ln(H2O)4(CH3CN)2][M(CN)8] · CH3CN [Ln = La, M = Mo( 1 ), W( 2 ); Ln = Ce, M = W( 3 )], were synthesized and characterized structurally. Single‐crystal X‐ray analysis reveals that 1 – 3 are isomorphous and consist of infinite one‐dimensional (1D) 3,3 rope‐ladder chains, in which the 12‐membered puckered square Ln2M2(CN)4 is the basic building unit. The 1D chains are further linked through interchain hydrogen bonds, resulting in a three‐dimensional (3D) supramolecular network. 相似文献
149.
A laser beam propagating through turbulence experiences random amplitude and phase fluctuations, which can severely degrade the performance of free space optical communication systems. It this letter, time diversity is demonstrated as a technique which can decrease turbulence influence. Statistically, laser propagation along an atmospheric path is uncorrelated with an earlier-time path for a time interval greater than the atmospheric turbulence correlation time. To estimate time diversity system performance, a 2.2-km optical link is set up for comparing the fade probability of a system using time diversity with a system not using time diversity. The experimental results obtained under different turbulence conditions are shown which are in good agreement with the theory. 相似文献
150.
Ai Hua Fan 《Journal d'Analyse Mathématique》2002,86(1):271-287
Let β > 1 be a Pisot number andg be a positive Hölder continuous function with period one and g(0) = 1. The multiperiodic functionG(ξ)=Π n=0 ∞ g(ξ/βn) is studied and the asymptotic behaviour ofI G(T) = ∫ 0 T G(ξ)dξ investigated. We prove that the limit of logI(T)/ logT exists asT tends to infinity. We also provide a method to calculate this limit for the caseg(ξ) = cos2 2πξ, corresponding to the Fourier transform of the Bernoulli convolution associated to the golden number (or some of its generalizations). 相似文献