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81.
Abstract Gastrodigenin, also known as 4-hydroxybenzyl alcohol (HBA), is one of the main components of Gastrodia elata, which is a perfect lead compound of natural products. In order to get new active compounds, we modified the structure of HBA through esterification with carboxylic acid, and got a series of derivatives in which 4-hydroxybenzyl alcohol 2-naphthoate (NHBA) showed stronger antidepressant activity than HBA. In this paper, we firstly evaluated the antidepressant activity of NHBA by tail suspension test (TST) and forced swimming test (FST). Then, we carried out the biochemical assay and western blot to determine its mechanism. The results displayed that NHBA could increase the content of serotonin, dopamine, norepinephrine, γ-aminobutyric acid, brain-derived neurotrophic factor (BDNF) and tropomyosin receptor kinase B (TrkB) in mice brain. It suggested that NHBA exhibited an antidepressant-like effect through monoaminergic system, GABAergic system and BDNF/TrkB signaling pathways. 相似文献
82.
本文从理论上研究了在双色频率梳激光场驱动下多光子谐波辐射光谱中的相位突变现象。我们利用Floquet理论非微扰地模拟了频率梳激光场与原子分子等量子系统的相互作用过程。谐波辐射信号是多光子偶极跃迁相干叠加的结果,通过调节频率梳激光场间的相对相位,可以相干地控制谐波辐射信号的强度。通过对谐波信号进行傅里叶变换,可以提取不同跃迁路径的相对相位信息。我们通过改变频率梳组激光场的强度和频率组分实现多光子跃迁频率,让其跨越共振跃迁频率时,谐波相位会发生突变。从而可以观测超强激光场驱动下量子系统共振跃迁频率的斯塔克能移。 相似文献
83.
Nonlinear Dynamics - Aiming to isolate disturbance vibration for heavy machines with low frequency, a novel hydro-pneumatic vibration isolator with high-static and low-dynamic (HSLD) stiffness is... 相似文献
84.
In recent years, nanomaterial-based drug delivery carriers have become some of the most attractive to be studied. The purpose of this study is to investigate the interaction of C60 fullerene, carbon nanotube and graphene having porphyrin-like FeN4 clusters with a non-steroidal anti-inflammatory drug (ibuprofen) by means of the density functional theory. Results showed that the graphene with FeN4 clusters could remarkably increase the tendency of graphene for adsorption of ibuprofen drug. Also, our ultraviolet–visible results show that the electronic spectra of the complexes exhibit a blue shift toward lower wavelengths (higher energies). It was found that Ibp/FeN4-graphene had high chemical reactivity, which was important for binding of the drug onto the target site. In order to go further and gain insight into the binding features of considered systems with ibuprofen drug, the Atoms in Molecules analysis was performed. Our results determine the electrostatic features of the Ibp/FeN4-graphene bonding. Consequently, the results demonstrated that the FeN4-graphene could be used as potential carriers for the delivery of ibuprofen drug. 相似文献
85.
Juan Luis García Guirao Jaume Llibre Wei Gao 《Journal of Difference Equations and Applications》2020,26(2):203-208
The objective of this work is to present sufficient conditions for having positive topological entropy for continuous self-maps defined on a closed surface by using the action of this map on the homological groups of the closed surface. 相似文献
86.
Second harmonic magnetoacoustic responses of magnetic nanoparticles in magnetoacoustic tomography with magnetic induction 下载免费PDF全文
Due to the unique magnetic, mechanical and thermal properties, magnetic nanoparticles(MNPs) have comprehensive applications as the contrast and therapeutic agents in biomedical imaging and magnetic hyperthermia. The linear and nonlinear magnetoacoustic responses determined by the magnetic properties of MNPs have attracted more and more attention in biomedical engineering. By considering the relaxation time of MNPs, we derive the formulae of second harmonic magnetoacoustic responses(2H-MARs) for a cylindrical MNP solution model based on the mechanical oscillations of MNPs in magnetoacoustic tomography with magnetic induction(MAT-MI). It is proved that only the second harmonic magnetoacoustic oscillations can be generated by MNPs under an alternating magnetic excitation. The acoustic pressure of the 2H-MAR is proportional to the square of the magnetic field intensity and exhibits a linear increase with the concentration of MNPs. Numerical simulations of the 2H-MAR are confirmed by the experimental measurements for various magnetic field intensities and solution concentrations using a laser vibrometer. The favorable results demonstrate the feasibility of the harmonic measurements without the fundamental interference of the electromagnetic excitation, and suggest a new harmonic imaging strategy of MAT-MI for MNPs with enhanced spatial resolution and improved signal-to-noise ratio in biomedical applications. 相似文献
87.
88.
Bijun Gao Jin Zhou Hongliang Wang Guping Zhang Jinghui He Qingfeng Xu Najun Li Dongyun Chen Hua Li Jianmei Lu 《中国化学》2019,37(2):148-154
Tetracycline (TC) and other antibiotics accumulated in groundwater and soil pollute ecological environment and threaten human health. Gold nanoparticles doped on photocatalysts are able to enhance the photodegradation efficiency during removing these antibiotics, but preparation of Au nanoparticles of well‐dispersion on photocatalysts remains challenging. In this work, zeolite imidazolate (ZIF‐8) was employed as the precursor to prepare Au@ZnO photocatalyst via impregnation and in‐situ reduction method to efficiently degrade the tetracycline in the aqueous solution. Au nanoparticles are of 10 nm in size and uniformly dispersed on the surfaces of ZnO microstructures. The as‐prepared Au@ZnO is able to remove 85.5% of TC of 0.010 mg/mL within 2 h, presenting higher photocatalytic activity than pure ZnO catalyst. Most importantly, the catalyst shows its superior stability after five cycles without structure and activity changing. The mechanism of the photocatalytic degradation was discussed in detail. 相似文献
89.
Wen-Wen Zhao Ke Zan Jing-Yue Wu Wei Gao Jie Yang Yin-Ying Ba 《Natural product research》2019,33(17):2435-2439
One new triterpenoid (1) and seven known analogues (2–8) were isolated from the leaves of Ilex hainanensis Merr.. Their structures were established by analysis of their MS, 1D and 2D NMR spectroscopic data and comparison with those in the literature. The antibacterial activity of compounds 1–8 were evaluated by determination of minimum inhibitory concentration using twofold microdilution broth method against Streptococcus mutans ATCC 25175 (Gram-positive) and Fusobacterium nucleatum ATCC 10953 (Gram-negative). Compounds 3 and 5 showed significant antibacterial activity against S. mutans in concentration of 9.7 μg/mL, while showed little antibacterial activity against F. nucleatum. On the contrary, the inhibitory activity of compounds 1, 2 and 6 against F. nucleatum were higher than them against S. mutans. 相似文献
90.
Qin Dou Zhao Bin Gao Diankui Xu Lizhi 《Journal of Thermal Analysis and Calorimetry》2022,147(12):6893-6900
Journal of Thermal Analysis and Calorimetry - The leakage of scroll compressor can reduce the working efficiency and cause risk, it is significant to study it in depth, thermal analysis of leakage... 相似文献