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891.
一种香豆素化合物的结构鉴定 总被引:2,自引:0,他引:2
一种香豆素化合物的结构鉴定陈望忠焦克芳(北京军事医学科学院毒物药物研究所,北京100850)关键词2,15-十六烷二酮3-乙酰基-6-乙氧羰基-5-羟基-4,7-二甲基香豆素NMR中图分类号O656.22麝香酮是麝香中的主要成分之一,Stol[1]采... 相似文献
892.
Qing-Qing Wang Shu-Guang Zhang Jian Jiao Peng Dai Wei-Hua Zhang 《Molecules (Basel, Switzerland)》2021,26(2)
A series of fluorinated 7-hydroxycoumarin derivatives containing an oxime ether moiety have been designed, synthesized and evaluated for their antifungal activity. All the target compounds were determined by 1H-NMR, 13C-NMR, FTIR and HR-MS spectra. The single-crystal structures of compounds 4e, 4h, 5h and 6c were further confirmed using X-ray diffraction. The antifungal activities against Botrytis cinerea (B. cinerea), Alternaria solani (A. solani), Gibberella zeae (G. zeae), Rhizoctorzia solani (R. solani), Colletotrichum orbiculare (C. orbiculare) and Alternaria alternata (A. alternata) were evaluated in vitro. The preliminary bioassays showed that some of the designed compounds displayed the promising antifungal activities against the above tested fungi. Strikingly, the target compounds 5f and 6h exhibited outstanding antifungal activity against B. cinerea at 100 μg/mL, with the corresponding inhibition rates reached 90.1 and 85.0%, which were better than the positive control Osthole (83.6%) and Azoxystrobin (46.5%). The compound 5f was identified as the promising fungicide candidate against B. cinerea with the EC50 values of 5.75 μg/mL, which was obviously better than Osthole (33.20 μg/mL) and Azoxystrobin (64.95 μg/mL). Meanwhile, the compound 5f showed remarkable antifungal activities against R. solani with the EC50 values of 28.96 μg/mL, which was better than Osthole (67.18 μg/mL) and equivalent to Azoxystrobin (21.34 μg/mL). The results provide a significant foundation for the search of novel fluorinated 7-hydroxycoumarin derivatives with good antifungal activity. 相似文献
893.
以“原电池”教学为例,通过设置紧密联系的任务,结合手持技术,探究“如何获得稳定工作的电池”和“如何获得高效的电池”的原理。充分运用物理、化学已有的认知模型,进行跨学科概念的教学,培养学生从宏观和微观水平上收集证据、分析证据的能力,发展“证据推理与模型认知”的学科核心素养。 相似文献
894.
895.
快速准确的治疗药物监测对于临床上确保患者用药有效性及安全性至关重要,同时也能够确定患者用药依从性,制定个性化给药方案。该文以两支疏水性略有差异的反相分离柱Supersil ODS2和SinoChrom ODS-BP,及强阳离子交换捕集柱Supersil SCX构建了基于集成化的多柱二维液相色谱系统。通过二维色谱接口,以pH 3.0的磷酸缓冲液调整第一维分离后的洗脱液组成,降低有机相含量并维持pH,改善了中心切割模式下样品转移和捕集的效率。利用该多柱二维液相色谱系统发展了血清中氨磺必利的二维液相色谱检测方法,血清样品经过高氯酸和甲醇混合液沉淀蛋白质并离心后直接300 μL大体积进样,以乙腈/磷酸缓冲液(25 mmol/L, pH 3.0)(20/80, v/v)作为第一维分离流动相,磷酸缓冲液(25 mmol/L, pH 3.0)作为捕集过程的稀释流动相,乙腈/磷酸缓冲液(25 mmol/L, pH 7.0)(25/75, v/v)作为第二维分离流动相,12 min内即可完成分析。方法在10~200 ng/mL的范围内线性相关性良好(r=0.9998)。样品在50 ng/mL和100 ng/mL两个加标浓度下的回收率稳定,在73.7%~76.8%之间。方法的检出限为7.28 ng/mL,定量限为24.27 ng/mL,能够满足《神经精神药理学治疗药物检测共识指南》中推荐的药物监控范围要求。由于该系统日常使用及维护成本较低,且能够实现自动化分析,故该方法适合在临床上用于治疗药物监测研究。 相似文献
896.
Furong Li Prof. Dr. Zhicheng Sun Shouzheng Jiao Yutong Ma Qingqing Zhang Yang Zhou Jinyue Wen Prof. Dr. YuanYuan Liu 《化学:亚洲杂志》2021,16(1):102-109
The fabrication of desired anti-magnetic materials for irradiation shielding remains a challenge to date. In this work, a new type of dual-functional magnetic shielding phase change microcapsules with paraffin as the core, melamine-formaldehyde (MF) resin as the shell and doped with magnetic particles in the shell were successfully prepared by in situ polymerization. The magnetic particles were dispersed in the shell layer by coating a hydrophilic emulsifier on the surface. These microcapsules were specifically applied to the field of magnetic shielding by the screen printing method. The effect of magnetic particles on the performance of phase-change microcapsules was examined by differential scanning calorimetry and thermogravimetric analyses. The magnetic type and magnetic strength of the microcapsules were studied by the vibrating sample magnetometer. Moreover, the effects of different magnetic particles (Fe3O4, CrO2) on the performance of phase change microcapsules and the magnetic strength of microcapsules were compared. The results showed that these two kinds of magnetic particles can greatly improve the phase change latent heat, thermal stability, and thermal conductivity of the microcapsules. Finally, the great magnetic shielding role of these microcapsules was demonstrated in both static and pulsed magnetic fields through the screen printing of magnetic shielding ink on wallpaper. Incorporating 0.5 g Fe3O4 inside of microcapsules, specifically, the magnetic intensity was effectively reduced by ∼250 Oe within a short distance in the static field. We expect that these magnetic microcapsules hold great potential for the shielding of irradiations via the screen printing on various substrates. 相似文献
897.
Deling Yuan Chen Zhang Shoufeng Tang Zetao Wang Qina Sun Xiaoyu Zhang Tifeng Jiao Qingrui Zhang 《中国化学快报》2021,32(11):3387-3392
Hydrogen peroxide (H2O2) disproportionation, iron precipitation, and narrow pH range are the drawbacks of traditional Fenton process. To surmount these barriers, we proposed a ferric ion (Fe3+)-ascorbic acid (AA) complex catalyzed calcium peroxide (CaO2) Fenton-like system to remove organic dyes in water. This collaborative Fe3+/AA/CaO2 system presented an obvious improvement in the methyl orange (MO) decolorization, and also effectively eliminated other dyes. Response surface method was employed to optimize the running parameters for this coupling process. Under the optimized arguments (2.76 mmol/L Fe3+, 0.68 mmol/L AA, and 4 mmol/L CaO2), the MO removal achieved 98.90% after 15 min at pH 6.50, which was close to the computed outcome of 99.30%. Furthermore, this Fenton-like system could perform well in a wide range of pH (3–11), and enhance the H2O2 decomposition and Fe ions recycle. The scavenger experiment result indicated that hydroxyl radical, superoxide anion free radical, and singlet oxygen were acted on the dye elimination. Moreover, electron spin resonance analysis corroborated that the existences of these active species in the Fe3+/AA/CaO2 system. This study could advance the development of Fenton-like technique in organic effluent disposal. 相似文献
898.
单摆作谐振动的最大摆角的分析 总被引:2,自引:0,他引:2
本文根据实验上的微小偏差准则和试验中的最小可分辨时间来确定单摆作谐振动时的最大摆角 相似文献
899.
Lei Tang Yong Wu Jiao Lu Zhi Rong Zhang Jin Cheng Yang Li Hai 《中国化学快报》2007,18(5):513-515
A novel bifunctional compound carrying cluster thiogalactoside as the cell targeting ligands was synthesized for gene delivery to hepatocytes. Tetra-antennary dendr-OMs4 5 was used as a scaffold for the attachment of three galactosides, while the other mesylate end was linked with cholesterol through poly(ethylene glycol) chain. This design provided an effective entry for the synthesis of the bifunctional compound. 相似文献
900.
Zhao-Xian Yu Zhi-Yong Jiao Fu-ping Liu 《International Journal of Theoretical Physics》2008,47(6):1625-1629
By using of the invariant theory, we have studied the phase of exciton emission in a semiconductor microcavity, the dynamical
and geometric phases are presented respectively. The Aharonov-Anandan phase is also obtained in the case of cyclical evolution. 相似文献