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排序方式: 共有152条查询结果,搜索用时 18 毫秒
51.
X Kong J Qin Z Li A Vultur L Tong E Feng G Rajan S Liu J Lu Z Liang M Zheng W Zhu H Jiang M Herlyn H Liu R Marmorstein C Luo 《Organic & biomolecular chemistry》2012,10(36):7402-7417
Oncogenic mutations in critical nodes of cellular signaling pathways have been associated with tumorigenesis and progression. The B-Raf protein kinase, a key hub in the canonical MAPK signaling cascade, is mutated in a broad range of human cancers and especially in malignant melanoma. The most prevalent B-Raf(V600E) mutant exhibits elevated kinase activity and results in constitutive activation of the MAPK pathway, thus making it a promising drug target for cancer therapy. Herein, we describe the development of novel B-Raf(V600E) selective inhibitors via multi-step virtual screening and hierarchical hit optimization. Nine hit compounds with low micromolar IC(50) values were identified as B-Raf(V600E) inhibitors through virtual screening. Subsequent scaffold-based analogue searching and medicinal chemistry efforts significantly improved both the inhibitor potency and oncogene selectivity. In particular, compounds and possess nanomolar IC(50) values with selectivity for B-Raf(V600E)in vitro and exclusive cytotoxicity against B-Raf(V600E) harboring cancer cells. 相似文献
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分别将离子液体三正丁基甲铵(双三氟甲磺酰)亚胺盐([TBMA][NTf2])和1-乙基-3-甲基咪唑四氟硼酸盐([EMIM][BF4])与乙烯-醋酸乙烯共聚物弹性体(EVM)熔融共混制备复合材料,研究了离子液体与EVM的相容性及抗静电性能。 样品宏观透明性和SEM测试结果显示,[TBMA][NTf2]与EVM具有较好的相容性,相应的EVM/[TBMA][NTf2]复合材料的抗静电效果更好;热重分析(TGA)结果表明,[TBMA][NTf2]促进EVM热解,而[EMIM][BF4]对EVM的热稳定影响较小。 室温下在EVM中填加[TBMA][NTf2]的共混物表现出较好的柔性,当[TBMA][NTf2]质量分数为20%时,EVM/[TBMA][NTf2]复合材料的模量为0.58 MPa,断裂伸长率可达到2997%。 相似文献
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Binggang Xiao Hongya Lin Lihua Xiao Mingyue Gu Dongxu Yang Limin Hu Fenglei Guo Hongmei Mi 《Optical and Quantum Electronics》2018,50(10):370
A tunable terahertz dual band absorber consisted of graphene ribbon arrays and a graphene sheet with near-unity absorption is proposed and studied in this letter. With the coupling enhancement of graphene ribbon and graphene sheet, a perfect dual band absorber with absorption over 99% at 3.67 THz and 5.88 THz is achieved. Moreover, the principal of the coupling enhancement is analyzed. By optimizing the parameters of the structure, not only the absorption can be enhanced, but also the center of absorbing frequency could be shifted. Another approach to adjust the absorber–tuning the chemical potential of graphene which is more convenient and timely is investigated. Furthermore, the sensing of the refractive index is emulated by changing the refractive index of the medium on the top. Results show a broad application prospect of the absorber proposed in this paper. 相似文献
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Niobium-doped MnO2/reduced graphene oxide (Nb-MnO2/RGO) composite has been successfully synthesized via a simple microwave radiation method. The samples were systematically studied by X-ray diffraction (XRD), thermogravimetric analysis (TG), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), transmission electron microscope (TEM), and electrochemical measurements. As the anode material for lithium-ion batteries, the Nb-MnO2/RGO (molar ratio of Mn/Nb?=?50:1) (NMG50) showed an outstanding reversible discharge capacity of 556.6 mAh g?1 after 50 cycles with a capacity retention of 77% at a charge-discharge rate of 0.1 A g?1 and the reversible discharge capacity can still retain 223.3 mAh g?1 at a current of 1 A g?1, which is much higher than those for Nb-MnO2/RGO (molar ratio of Mn/Nb?=?10:1) (NMG10) and undoped MnO2/RGO (MG). The improved electrochemical performance could be attributed to the proper amount of Nb doping, which could enhance both the conductivity and the structure stability of MnO2. 相似文献
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本文研究了与Keggin结构相关的31种3大系列(2:18系列,1:11系列和双系列)杂多化合物的红外光谱,它们是:NP2W18(N=(CH3)4N^+,(C2H5)4N^+,(C4H9)4N^+),MP2W18(M=Li^+,Na^+,Ag^+,Cu^2+);KnZW11(Z=P,B,Ge,Si),MSiW11(M=Mn,Zn,Cu,Co,Ni)和M(PW11)2(M=Ce,Pr,Nd,Sm,E 相似文献
59.
This paper describes a two-step synthesis of 1-methyl-1,2,3,3a,4,8b-hexahydropyrrolo[3,2-f]pyrindine, a conformationally constrained nicotine analogue. The target molecule was effectively assembled by an intramolecular azomethine ylide-alkene [3+2] cycloaddition. The cyclization precursor, 4-allyl-3-pyridinecarboxaldehyde, was formed efficaciously in a single step from 3-pyridinecarboxaldehyde via sequential in situ protection, ortho lithiation, cuprate formation, allylation, and deprotection. The cuprate formation plays a vital role in minimizing/eliminating the extent of multiple alkylation. 相似文献
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Lu X Zhao M Kong H Cai J Wu J Wu M Hua R Liu J Xu G 《Journal of separation science》2004,27(1-2):101-109
Cigarette smoke condensate is a complex chemical matrix. Analysis of nitrogen-containing compounds present therein is very difficult because of the limitation of the peak capacity of conventional one-dimensional chromatography. Extensive and laborious sample preparation is frequently required or selective detectors are frequently used. In this study, the basic fraction of mainstream cigarette smoke condensate has been investigated by using comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry (GC x GC/TOFMS). Auto data processing by TOFMS software combined with manual identification was used to assign the components. 377 nitrogen-containing compounds, including 155 pyridine derivatives, 104 quinoline/isoquinoine derivatives, and 56 pyrazine derivatives were tentatively identified. By selecting appropriate unique masses and in the light of the component positions in the structured chromatogram, alkyl-substituted pyridines, pyrazines, and quinolines/isoquinolines were separately shown and further validated. The peaks of eight individual positional isomers of two-carbon-substituted pyridines and thirteen positional isomers of methyl-substituted quinolines/isoquinolines were further confirmed, based on linear incremental retention behavior in combination with TOFMS and the structured chromatogram of GC x GC. 相似文献