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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.
《Physics letters. A》2020,384(32):126831
In this Letter, we report the polarization-enhanced bulk photovoltaic effect (BPV) in pristine BiFeO3 (BFO) epitaxial film under standard 1 sun AM 1.5 G illumination. High-quality epitaxial BFO films are grown on (001)-oriented niobium doped-SrTiO3 substrates by pulsed laser deposition. The best BFO film based photovoltaic device achieves a power conversion efficiency of 0.0062% under standard illumination. Besides, it is found that the number of bipolar pulses plays a key role in improving the short-circuit current density and open-circuit voltage. These results are beneficial for further understanding of physical origin of the photovoltaic properties in ferroelectric oxides. 相似文献
83.
84.
实验验证了一种通过将氧化石墨烯分散液沉积在长周期光纤光栅的全光控制的相关研究。通过外加的垂直泵浦光的作用,氧化石墨烯吸收泵浦光产生热量,改变长周期光纤光栅的包层模式的相位差,由于热膨胀的作用改变了氧化石墨烯所覆盖部分的光栅周期,使得谐振谱发生了移动,其最大调制深度可达10.6 dB,谐振谱最大可红移12.8 nm。通过实验发现,沉积相同浓度氧化石墨烯分散液的次数影响实验结果,通过在相同光栅的相同位置分别沉积三次,发现沉积三次可以在光纤表面获得更加均匀的氧化石墨烯膜,进行了时间响应的测试,其中沉积三次后的长周期光纤光栅的响应速度可达0.61 ms,沉积多次氧化石墨烯分散液可以在光纤表面沉积得更加平整均匀,从而获得更大的导热性能。 相似文献
85.
The addition reaction of CH2OO?+?H2S → HSCH2OOH without and with catalyst X (X?=?H2O and (H2O)2) has been investigated by CCSD(T)-F12a/VTZ-F12//B3LYP/aug-cc-pVTZ method and canonical variational transition state theory with small curvature tunneling correction. When H2O was introduced in the CH2OO?+?H2S reaction, it not only acts as a catalyst for producing HSCH2OOH, but also plays as a reactant to forming HOCH2OOH. The formation channel of HSCH2OOH is more important than the formation channel of HOCH2OOH with its calculated rate constant larger by 11.0–43.2 times within the temperature 280–320?K. Then, (H2O)2 catalysed CH2OO?+?H2S → HSCH2OOH reaction has been taken into account with its rate lower 1.9–4.2 times than the reaction of CH2OO?+?H2S → HSCH2OOH with water. Also, CH2OO?+?H2S with H2O cannot compete with the CH2OO?+?H2S reaction without water. This is different from CH2OO?+?(H2O)2 reaction, which is about 4 orders of magnitude larger than the rate constant for CH2OO?+?H2O reaction. Such discrepancy is possible because C(CH2OO)···O(H2O) interaction has been enhanced more obviously by H2O as compared to that of C(CH2OO)···O(H2S) interaction. 相似文献
86.
基于Rasch模型对化学实验操作技能测试的评分者效应开展研究。通过对Infit、Outfit、t、怀特图和宽严度波动图等的分析,研究测试中评委的宽严度、内部一致性、外部一致性以及评委与考生间的偏差规律。得到系列减弱化学实验操作技能测试中评分者效应的建议。 相似文献
87.
88.
The swelling behavior of a temperature-sensitive poly-N-isopropylacrylamide(PNIPAM) hydrogel circular cylinder is studied subjected to combined extension-torsion and varied temperature. In this regard, a semi-analytical solution is proposed for general combined loading. A finite element(FE) analysis is conducted, subjecting a hydrogel cylinder to the combined extension-torsion and the varied temperature to evaluate the validity and accuracy of the solution. A user-defined UHYPER subroutine is developed and verified under free and constrained swelling conditions. The FE results illustrate excellent agreement with the semi-analytical solution. Due to the complexity of the problem, some compositions and applied loading factors are analyzed. It is revealed that for larger cross-linked density and larger ending temperature, the cylinder yields higher stresses and smaller radial swelling deformation. Besides, the radial and hoop stresses increase by applying larger twist and axial stretch. The hoop stresses intersect at approximately R/Rout = 0.58, where the hoop stress vanishes. Besides, the axial force has direct and inverse relationships with the axial stretch and the twist, respectively. However, the resultant torsional moment behavior is complex, and the position of the maximum point varies significantly by altering the axial stretch and the twist. 相似文献
89.
以苏州太平金融大厦为工程背景,针对其大跨裙摆屋盖的风荷载作用,首先采用RNG k-ε模型模拟分析了其平均风压分布规律,以及风向变化对屋盖表面风荷载体型系数的影响;其次,引入干扰因子IF,探讨了周边建筑对大跨裙摆屋盖风荷载的气动干扰作用。结果表明:0°风向下,走廊上方屋盖两侧区域出现“上吸下顶”的叠加作用;90°风向下屋盖北侧飘带末端区域受到狭道风效应出现正压集中现象;风向变化对大跨裙摆屋盖的风荷载体型系数分布影响较大;且周围建筑物对大跨裙摆屋盖的气动干扰效应明显,主要表现为风压“遮挡效应”,而局部区域表现为风压“放大效应”。 相似文献
90.