排序方式: 共有51条查询结果,搜索用时 15 毫秒
1.
Lighting Up MicroRNA in Living Cells by the Disassembly of Lock‐Like DNA‐Programmed UCNPs‐AuNPs through the Target Cycling Amplification Strategy 下载免费PDF全文
Keying Zhang Shuting Song Shan Huang Lin Yang Qianhao Min Xingcai Wu Feng Lu Jun‐Jie Zhu 《Small (Weinheim an der Bergstrasse, Germany)》2018,14(40)
Intracellular microRNAs imaging based on upconversion nanoprobes has great potential in cancer diagnostics and treatments. However, the relatively low detection sensitivity limits their application. Herein, a lock‐like DNA (LLD) generated by a hairpin DNA (H1) hybridizing with a bolt DNA (bDNA) sequence is designed, which is used to program upconversion nanoparticles (UCNPs, NaYF4@NaYF4:Yb, Er@NaYF4) and gold nanoparticles (AuNPs). The upconversion emission is quenched through luminescence resonance energy transfer (LRET). The multiple LLD can be repeatedly opened by one copy of target microRNA under the aid of fuel hairpin DNA strands (H2) to trigger disassembly of AuNPs from the UCNP, resulting in the lighting up of UCNPs with a high detection signal gain. This strategy is verified using microRNA‐21 as model. The expression level of microRNA‐21 in various cells lines can be sensitively measured in vitro, meanwhile cancer cells and normal cells can be easily and accurately distinguished by intracellular microRNA‐21 imaging via the nanoprobes. The detection limit is about 1000 times lower than that of the previously reported upconversion nanoprobes without signal amplification. This is the first time a nonenzymatic signal amplification method has been combined with UCNPs for imaging intracellular microRNAs, which has great potential for cancer diagnosis. 相似文献
2.
针对高频链直流变压器多模块特性与高频特性带来的仿真实现困难问题,提出了在RT-LAB仿真平台上实现其实时仿真的具体方法及理论分析。所提出的方法中,控制系统与主电路系统采用不同的仿真步长分别在CPU仿真器与FPGA仿真器中完成,能够在满足两者对仿真步长不同要求的基础上,实现实时仿真资源的充分利用。同时,对高频串联电感的分割原理进行了理论分析,以完成多个FPGA仿真模块的联合实时仿真运行,从而在根本上解决了高频链直流变压器由于多模块化与高频特性所带来的实时仿真矛盾。最后,利用上述理论与方法,完成了一个高频链直流变压器的实时仿真模型,并将其与Matlab离线仿真进行了对比实验。实时仿真实验结果证明了所提出的仿真方法和理论分析的正确性以及高频链直流变压器实时仿真的快速性与实用性。 相似文献
3.
4.
5.
6.
采用双辊铸轧法制备了ZK60镁合金条带,采用金相显微镜(OM)和动态机械分析仪(DMA)研究了热处理后ZK60镁合金条带的组织和阻尼性能。退火处理后,组织较为均匀。T6处理后组织转变为均匀的等轴晶。在温度-阻尼谱中出现了2个温度阻尼峰,P1峰为弛豫型阻尼峰,其激活能为132 kJ/mol,P2峰为非弛豫型再结晶阻尼峰。T6处理条件下,时效时间为6 h时,呈现典型的位错型应变-阻尼图谱;在其他时效时间下,呈现2种混合位错型的应变-阻尼图谱。T6态双辊铸轧ZK60镁合金的应变-阻尼性能遵循G-L理论。 相似文献
7.
正To improve the performance characteristics of highvoltage DC(HVDC)system,integrating the existing HVDC projects with DC transformer(DCT)on the DC side is a very effective technical method.According to the current research status and technology development 相似文献
8.
9.
钳位开关电容型DC/DC(Clamping Switched Capacitors-based DC/DC,CSC)是构建具有直流故障自清除能力直流变压器的有效模块。由于传统控制策略下的CSC中直流电压与电容电压存在着耦合效应,直流电压的变化将直接引起电容电压与交流环节电压幅值的变化,使得CSC在两端直流电压不匹配时可能发生软开关丢失、电流应力增大、功率损耗增加等运行性能下降的现象。鉴于此,为改善CSC在直流电压不匹配时的开关及效率性能,提出了一种基于可变占空比的CSC电容电压解耦控制策略。该策略可以在CSC的整个运行范围内保证交流电压幅值的自动匹配,对于改善CSC的整体运行性能具有明显效果。基于试验样机,验证了所提控制策略的正确性与有效性。 相似文献