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排序方式: 共有223条查询结果,搜索用时 187 毫秒
31.
Zhou  Jiawen  Zhu  Weiya  Zeng  Miao  Yang  Qingqing  Li  Ping  Lan  Linfeng  Peng  Junbiao  Li  Yuan  Huang  Fei  Cao  Yong 《中国科学:化学(英文版)》2019,62(12):1656-1665
Stable radicals are challenging to prepare due to their intrinsic high reactivity. Herein, three trisphenolamine radicals were readily synthesized and exhibited unexpected thermal/electrochemical stability and semiconductor property. These three nitroxide radicals could be considered as a class of aromatized nitro groups or HNO_3 derivatives. The closed-shell nitro-like and open-shell nitroxide resonance structure contribute to their outstanding stability. Furthermore, the tunable ground states, extremely low band gap and p-type charge transport properties were systematically investigated. More importantly, the work presents the concept of aromatic inorganic acid radical(AIAR) and aggregation-induced radical(AIR) mechanism to understand the intrinsic structureproperty relationship of these radicals. In addition, we provide a novel strategy for the design of stable and low bandgap radicals for organic electronics, magnetics, spintronics, etc.  相似文献   
32.
DNA damage repair through the nucleotide excision repair (NER) pathway is one of the major reasons for the decreased antitumor efficacy of platinum‐based anticancer drugs that have been widely applied in the clinic. Inhibiting the intrinsic NER function may enhance the antitumor activity of cisplatin and conquer cisplatin resistance. Herein, we report the design, optimization, and application of a self‐assembled lipid nanoparticle (LNP) system to simultaneously deliver a cisplatin prodrug together with siRNA targeting endonuclease xeroderma pigmentosum group F (XPF), a crucial component in the NER pathway. The LNP is able to efficiently encapsulate both the platinum prodrug and siRNA molecules with a tuned ratio. Both platinum prodrug and XPF‐targeted siRNA are efficiently carried into cells and released; the former damages DNA and the latter specifically downregulates both mRNA and protein levels of XPF to potentiate the platinum drug, leading to enhanced expression levels of apoptosis markers and improved cytotoxicity in both cisplatin‐sensitive and ‐resistant human lung cancer cells. Our results demonstrate an effective approach to utilize a multi‐targeted nanoparticle system that can specifically silence an NER‐related gene to promote apoptosis induced by cisplatin, especially in cisplatin‐refractory tumors.  相似文献   
33.
This work proposes a new texturing technique of monocrystalline silicon surface for solar cells with sodium hypochlorite. A mixed solution consisting of 5 wt% sodium hypochlorite and 10 vl% ethanol has been found that results in a homogeneous pyramidal structure, and an optimal size of pyramids on the silicon surface. The textured silicon surface exhibits a lower average reflectivity (about 10.8%) in the main range of solar spectrum (400–1000 nm).  相似文献   
34.
Caught on film : A semitransparent and intensely luminescent monolayer film of oriented Gd2O3:0.05 Eu platelet crystallites is fabricated by annealing the precursor hydroxide film (see scheme). The photoluminescence properties of the as‐transformed film are greatly improved over those of the hydroxide film, and are much more pronounced than those of the corresponding Gd2O3:0.05 Eu powder.

  相似文献   

35.
Yan F  Cao D  Wang M  Yang N  Yu Q  Dai L  Chen L 《Journal of fluorescence》2012,22(5):1249-1256
A novel rhodamine derivative (Rh-C), synthesized by the reaction of rhodamine ethylenediamine and cinnamoyl chloride, was evaluated as a chemoselective Hg(2+) ion sensor. Addition of Hg(2+) to an ethanol aqueous solution of the Rh-C resulted in a color change from colorless to obvious pink color together with distinctive changes in UV-vis absorption spectrum and fluorescence spectrum. However, other common alkali-, alkaline earth-, transition- and rare earth metal ions induced no or minimal spectral changes. The interaction of Hg(2+) and sensor Rh-C was proven to adopt a 1:1 binding stoichiometry and the recognition process is reversible. The chemosensor displayed a linear response to Hg(2+) in the range of 0.4-5?μM with a detection limit of 7.4?×?10(-8)?M. The sensor Rh-C was also successfully applied to the imaging of Hg(2+) in HL-7702 cells.  相似文献   
36.
DNA assembles that can perform "OR" and "AND" logic gate operations were fabricated. The feasibility of intelligent logic controlled release was demonstrated through the controlled organization of gold nanoparticles on the surface of mesoporous silica by stimuli-induced structural transformation of DNA ensembles.  相似文献   
37.
能量选择中子成像技术是利用特定范围波长(能量)的中子进行成像。在热/冷中子范围内(<25meV),能量选择中子成像技术主要基于布拉格边效应和衍射机制,相比常规中子成像技术不但可以显著提高图像对比度,而且能分析应变、应力、织构。在超热中子范围内(>1eV),能量选择中子成像技术主要基于中子共振吸收,中子截面随能量变化是同位素特有的,存在明显的共振吸收峰,因此可以进行同位素的“指纹”识别。能量选择中子成像技术在工程、材料、化学、物理、生物、考古等众多科研领域中有着非常广阔的应用前景。  相似文献   
38.
磁流变弹性体(magnetorheological elastomer,MRE)因其独特的场相关性能在工程应用领域引起了广泛关注.论文介绍了MRE的最新发展,重点介绍导电性MRE在材料设计、力学行为和实际应用等方面的研究现状.论文从高性能导电性MRE的研制开始,讨论了材料与结构设计中涉及的关键问题;介绍了导电性MRE材料在磁场作用下的磁、力、电学行为的耦合作用机理和相关物理模型;之后对导电性MRE器件的研究现状进行了总结;最后展望了导电性MRE的发展潜力和面临的挑战.  相似文献   
39.
Dimethyl sulfoxide (DMSO) is a universally used solvent in various synthetic reactions, and trace amounts of DMSO residual are often seen on the surface of chemical product. It is difficult to quickly determine whether the residual DMSO is washed completely. This work reports a CdII metal–organic framework (MOF) SXU-4 which can detect trace amounts of DMSO in various solvents. Fluorescence experiments reveal its turn-on fluorescence effect toward DMSO with high selectivity and sensitivity, indicating that it can be used as an effective luminescent probe for rapid chemical product purity detection by testing the washing solution. Crystallographically characterized DMSO loaded SXU-4 (DMSO@ SXU-4 ), in combination with computational results uncover that the enhanced DMSO–MOF conjugation through multiple DMSO–MOF supramolecule interactions and charge rearrangement are the main causes of fluorescence intensification.  相似文献   
40.
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