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| 1 | Concentration quenching in transparent glass ceramics containing Er^(3+):NaYF_4 nanocrystals显示文摘In this work, we have studied the concentration quenching in transparent glass ceramics containing Er3+:NaYF4 nanocrystals. For different concentrations, the emission spectra and decay curves of the 4I13/2→4I15/2 emission were measured. The Er-concentration dependence of integrated intensity and lifetime of 4I13/2→4I15/2 emission are showed. With the increase of the Er3+ doping concentration, the 1.5 m fluorescence emission first increases, then decreases, and the lifetime falls gradually. With 980 nm excitation, the efficiency of the energy transfer from Er3+ to quenching centers reaches 73.73% for the sample with 4 mol% Er3+. Meanwhile, owing to the relation of fluorescence integrated intensity and Er-concentration, a dipole-dipole quenching mechanism in the framework of a limited diffusion regime has been proved. Using the limited diffusion case, the critical concentration for quenching has been determined from a fitting equation of the lifetime and Er-concentration. The fitting result shows the critical concentration for quenching is higher than the values obtained in Er-doped different glass by an order of magnitude. | HUANG XingYong CHEN DaQin LIN Lin WANG ZheZhe WANG YuanSheng FENG ZhuoHong ZHENG ZhiQiang | 2012 | Science China(Physics,Mechanics & Astronomy)2012，55，7： | 5 |
| 2 | Activation of the wnt/β-catenin/CYP1B1 pathway alleviates oxidative stress and protects the blood-brain barrier under cerebral ischemia/reperfusion conditions显示文摘Accumulating evidence suggests that oxidative stress and the Wnt/β-catenin pathway participate in stroke-induced disruption of the blood-brain barrier.However,the potential links between them following ischemic stroke remain largely unknown.The present study found that cerebral ischemia leads to oxidative stress and repression of the Wnt/β-catenin pathway.Meanwhile,Wnt/β-catenin pathway activation by the pharmacological inhibito r,TWS119,relieved oxidative stress,increased the levels of cytochrome P4501B1(CYP1B1)and tight junction-associated proteins(zonula occludens-1[ZO-1],occludin and claudin-5),as well as brain microvascular density in cerebral ischemia rats.Moreove r,rat brain microvascular endothelial cells that underwent oxygen glucose deprivation/reoxygenation displayed intense oxidative stress,suppression of the Wnt/β-catenin pathway,aggravated cell apoptosis,downregulated CYP1B1and tight junction protein levels,and inhibited cell prolife ration and migration.Overexpression ofβ-catenin or knockdown ofβ-catenin and CYP1B1 genes in rat brain mic rovascular endothelial cells at least partly ameliorated or exacerbated these effects,respectively.In addition,small interfering RNA-mediatedβ-catenin silencing decreased CYP1B1 expression,whereas CYP1B1 knoc kdown did not change the levels of glycogen synthase kinase 3β,Wnt-3a,andβ-catenin proteins in rat brain microvascular endothelial cells after oxygen glucose deprivatio n/reoxygenation.Thus,the data suggest that CYP1B1 can be regulated by Wnt/β-catenin signaling,and activation of the Wnt/β-catenin/CYP1B1 pathway contributes to alleviation of oxidative stress,increased tight junction levels,and protection of the blood-brain barrier against ischemia/hypoxia-induced injury. | Xingyong Chen Nannan Yao Yanguang Mao Dongyun Xiao Yiyi Huang Xu Zhang Yinzhou Wang | 2024 | Neural Regeneration Research2024，19，7： | 0 |
| 3 | Theoretical dissection of superconductivity in two-dimensional honeycomb borophene oxide B_(2)O crystal with a high stability显示文摘Atomically thin borophene has recently been synthesized experimentally,significantly enriching the boron chemistry and broadening the family of two-dimensional(2D)materials.Recently,oxides of 2D materials have been widely investigated for nextgeneration electronic devices.Based on the first-principles calculations,we predict the existence of the superconductivity in honeycomb borophene oxide(B_(2)O),which possesses a high stability and could be potentially prepared by intrinsically incorporating oxygen into the recently synthesized borophene. | Luo Yan Peng-Fei Liu Hengtao Li Yong Tang Junjie He Xingyong Huang Bao-Tian Wang Liujiang Zhou | 2020 | npj Computational Materials2020，，1： | 0 |
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