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61.
A one-step copper-carbodimide elimination was used to provide the (E)-dehydroisoleucine moiety in the phomopsin side chain stereoselectively. An efficient approach to the phomopsin tripeptide side chain was developed to be used in the total syntheses of phomopsins A and B. 相似文献
62.
Qiang Wu Miao Du Tao Ye Yong-gang Shangguan Jian-ping Zhou Qiang Zheng 《Colloid and polymer science》2009,287(8):911-918
Interactions between anionic polyelectrolyte, poly(acrylic acid) (PAA), and cationic surfactant, alkyltrimethylammonium bromide
(C
n
TAB), were investigated by rheological measurements in semidilute PAA solution. The dependences of the rheological behavior
on the chain length of the surfactant, PAA neutralization degree, and temperature were discussed. The results revealed that
both dodecyl and cetyltrimethylammonium bromides (C12TAB and C16TAB) could increase the viscosity of PAA solution when the surfactant amounts surpassed a critical surfactant concentration
(C
c), and C
c of C16TAB was lower than that of C12TAB at same PAA neutralization degree. The increase of viscosity is attributed to the surfactant micelles bridging of the
polymer chains and confine the mobility PAA chain. On the other hand, it is found that the hydrogen bonding also played an
important role in the PAA–C
n
TAB system, especially in lower neutralization degree PAA solution, which results in the viscosity increase rapidly with the
added surfactant into lower neutralization degree PAA solution. 相似文献
63.
Utilizing a three-particle W state, we come up with a protocol for the teleportation of an unknown two-particle entangled state. It is shown that the teleportation can be deterministically and exactly realized. Moreover, two-particle entanglement teleportation is generalized to a system consisting of many particles via a three-particle W state and a multi-particle W state, respectively. All unitary transformations performed by the receiver are given in a concise formula. 相似文献
64.
Reactions of diesel soot and NOx with and without O2 were carried out over CuFe2O4 catalyst. The ignition temperature of soot with the NO+O2 feed was lower than that in O2 or NO but close to those in NO2 and NO2+O2, indicating the implication of NO2 especially in decreasing the ignition temperature. On the other hand, the reduction of NOx into N2 was enhanced by coexisting O2. Based on these results and mechanisms of O2-soot and NO-soot reactions, the possible reaction mechanism of the simultaneous NOx-soot removal with the NO+O2 feed has been proposed. 相似文献
65.
铈钼氧化物表面氧性质和催化性能 总被引:4,自引:0,他引:4
在甲苯选择性氧化制苯甲醛反应中,Mo基氧化物是一类重要的催化剂[1].通常的认识是反应物与催化剂表面晶格氧作用,并通过催化剂本身的还原和氧化的循环过程促使反应进行。生成产物.因此,催化剂表面不同氧物种的热脱附性能应与催化反应性能密切相关.对于Ce-Mo氧化物的TPD-MS研究,尚未见文献报导.为了能获得该方面的信息,本文应用程序升温脱附-质谱检测(TP-MS)联用技术,对Ce-Mo氧化物样品进行了表面氧TPD谱测定和动力学参量等计算,并试图与其催化性能进行关联.1实验部分1.1样品的制备和表征分别将一定质量的硝酸铈铵和仲… 相似文献
66.
Shangrong Wu Linlin Wang Nan Zhang Ying Liu Dr. Wei Zheng Ang Chang Dr. Fuyi Wang Dr. Songqin Li Dr. Dihua Shangguan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(17):6037-6047
G‐quadruplex (G4)‐forming sequences are prevalent in the genome and are considered to play important roles in gene regulation, and hence have been viewed as potential therapeutic targets in oncology. However, the structures and functions of most G4s in the genome are poorly understood. Therefore, the development of fluorescent probes and ligands for G4s is important for G4 research and drug discovery. Herein, we report a new G4 ligand, 2,9‐bis[4‐(4‐methylpiperazin‐1‐yl)styryl]‐1,10‐phenanthroline (BMSP), which was synthesized by a simple process. BMSP exhibits almost no fluorescence in aqueous buffer. The interaction of BMSP with G4s greatly enhances its fluorescence with a large Stokes’ shift of 160 nm. Antiparallel human telomeric G4s exhibit the strongest binding affinity (Kd≈0.13 μm ) to BMSP and induce a fluorescence enhancement of up to 150‐fold. BMSP binds to G4s through π–π stacking on the terminal G‐quartets. BMSP can enter live cells, and it strongly inhibits the growth of cancer cells rather than causing cell death. Our results suggest that BMSP has the potential to serve both as a fluorescent probe for some G4s and as a chemotherapeutic agent for cancer treatment. 相似文献
67.
68.
Zhao R Fanga C Yu X Liu Y Luo J Shangguan D Xiong S Su T Liu G 《Journal of chromatography. A》2005,1064(1):59-66
The affinity inhibitor of fusion peptide of influenza A virus has been studied using a combination of high-performance affinity chromatography (HPAC) and combinatorial peptide libraries. Fusion peptide (FP) (1-11) of influenza A virus was used as the affinity ligand and immobilized onto the poly(glycidyl methacrylate) (PGMA) beads. Positional scanning peptide libraries based on antisense peptide strategy and extended peptide libraries were designed and synthesized. The screening was carried out at acidic pH (5.5) in order to imitate the environment of virus fusion. A hendecapeptide FHRKKGRGKHK was identified to have a strong affinity to the FP (1-11). The dissociation constant of the complex of the hendecapeptide and the FP (1-11) is 3.10 x 10(-6) mol l(-1) in a physiological buffer condition. The polypeptide has a fairly inhibitory effect on three different strains of influenza A virus H1N1 subtype. 相似文献
69.
氮杂冠醚聚硅氧烷固定液的色谱保留机理 总被引:3,自引:0,他引:3
氨杂冠醚聚硅氧烷是一类呈中等极性的新颖气相色谱固定液.本文通过测定醇、酯、卤代烃和苯系列化合物的色谱保留值和相应势力学参数,研究它对上述不同化合物的保留机理及其分子识别的热力学性质 相似文献
70.
Shangguan N Katukojvala S Greenberg R Williams LJ 《Journal of the American Chemical Society》2003,125(26):7754-7755
A new amide synthesis strategy based on a fundamental mechanistic revision of the reaction of thio acids and organic azides is presented. The data demonstrate that amines are not formed as intermediates in this reaction. Alternative mechanisms proceeding through a thiatriazoline intermediate are suggested. The reaction has been applied to the preparation of simple and architecturally complex amides that are difficult to access using conventional methods. The reaction is chemoselective, effective for unprotected substrates, and compatible with aprotic and protic solvents, including water. 相似文献