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71.
借助密度泛函量子力学程序对硝基、甲氧基和羟基3种吸电子基团对[60]富勒烯吡咯烷空间结构的影响进行了研究。结果表明,结构优化后的[60]富勒烯吡咯烷衍生物的LUMO与HOMO能量差ΔE并不随基团吸电子能力的增强而增加,吸电子基团对[60]富勒烯衍生物吡咯烷键长和键角的影响大小为NO2>OH>OCH3。 相似文献
72.
73.
74.
对姜黄素衍生物类药物的结构修饰进行归类,探讨了姜黄素衍生物的生物活性与化学结构的关系,分析了姜黄素衍生物中化学基团对生物活性的影响,为以后合成具有高效专一的生物活性姜黄素衍生物提供依据。 相似文献
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76.
Wanqing Wu Long Min Lizhi Zhu Chi‐Sing Lee 《Advanced Synthesis \u0026amp; Catalysis》2011,353(7):1135-1145
A highly enantioselective catalytic Diels–Alder (DA) cycloaddition of 2H‐pyran‐2,5‐diones (synthon of 5‐hydroxy‐2‐pyrones) has been developed with a Cinchona‐derived thiourea as the catalyst. The conditions were optimized by using 0.2 equiv. of the catalyst and 0.1 equiv. of formic acid in 2‐propanol at room temperature, which afforded the DA products in yields of up to 90% (exo/endo=5.5:1, 98% ee) with trans‐β‐nitrostyrene derivatives as the dienophiles. The structure/activity relationships of the bifunctional catalyst and the effects of the steric, electronic and hydrogen‐bonding properties of the dienophiles have been studied. 相似文献
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78.
关于多元函数中值定理“中间点”的渐近性 总被引:1,自引:1,他引:1
孙弘安 《南方冶金学院学报》1989,10(1):65-68
本文讨论了矩形域上的二元函数微分中值定理的“中间点”当矩形域收缩为一点时的渐近性. 相似文献
79.
Maria Jos Rodríguez Francisca Herrera Wendy Donoso Ivn Castillo Roxana Orrego Daniel R. Gonzlez Jessica Zúiga-Hernndez 《International journal of molecular sciences》2020,21(22)
Liver fibrosis is a complex process associated to most types of chronic liver disease, which is characterized by a disturbance of hepatic tissue architecture and the excessive accumulation of extracellular matrix. Resolvin E1 (RvE1) is a representative member of the eicosapentaenoic omega-3 lipid derivatives, and is a drug candidate of the growing family of endogenous resolvins. Considering the aforementioned, the main objective of this study was to analyze the hepatoprotective effect of RvE1 in a rat model of liver fibrosis. Male Sprague-Dawley rats received diethylnitrosamine (DEN, 70 mg/mg body weight intraperitoneally (i.p)) as an inductor of liver fibrosis once weekly and RvE1(100 ng/body weight i.p) twice weekly for four weeks. RvE1 suppressed the alterations induced by DEN, normalizing the levels of alanine aminotransferase (ALT), albumin, and lactate dehydrogenase (LDH), and ameliorated DEN injury by decreasing the architecture distortion, inflammatory infiltration, necrotic areas, and microsteatosis. RvE1 also limited DEN-induced proliferation through a decrease in Ki67-positive cells and cyclin D1 protein expression, which is related to an increase of the levels of cleaved caspase-3. Interestingly, we found that RvE1 promotes higher nuclear translocation of nuclear factor κB (NF-κB)p65 than DEN. RvE1 also increased the levels of nuclear the nuclear factor erythroid 2–related factor 2 (Nrf2), but with no antioxidant effect, measured as an increase in glutathione disulfide (GSSG) and a decrease in the ratio of glutathione (GSH)/GSSG. Taken together, these results suggest that RvE1 modulates the fibrogenesis, steatosis, and cell proliferation in a model of DEN induced fibrosis. 相似文献
80.
In this paper, two new analytical attractive (alpha) functions and their derivatives in bulk and nanoconfined pores are developed based on the virial equation of state (EOS) and statistical thermodynamics and are evaluated at different conditions for the first time. A cubic EOS is modified to nanometer scale and applied to predict the thermodynamic and phase properties in bulk and nanoconfined pores coupled with the new analytical alpha functions. The nanoscale-extended EOS coupled with the analytical alpha functions are validated to be accurate by means of the experimental data for the thermodynamic and phase calculations. The alpha functions and dimensionless attractive term A for the O2, Ar, CO2, N2, and C1-C10 are always positive and monotonically decrease with the temperature increases at T ≤ 2000 K in the bulk phase, whereas the second virial coefficients (B2) are always negative and increase with the temperature increases. Moreover, the alpha functions, A, and B2 for all of components remain constant with the decreasing pore radius until rp = 50 nm, the former two of which decrease while the latter one increases by further reducing the pore radius. It should be noted that the intermolecular attractive force (ie, A) is a function of the pressure, which is gradually increased at P ≤ 10 MPa though drastically increases afterwards. Also, the enhanced confinement effects lead the same-component intermolecular attractive forces to be smaller. The analytical formulations in the SRK type slightly outperform in the gaseous or light component cases, while those in the PR type are better for the heavy component cases in terms of the thermodynamic property calculations, both of which are compatible with the modified EOS and analytical alpha functions. 相似文献