http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Effect of particle size of PtRu nanoparticles embedded in WO3 on electrocatalysis.
Yoo, Sung Jong,Park, Hee Young,Hwang, Seung Jun,Pyo, Sung Gyu,Kim, Soo-Kil,Sung, Yung-Eun,Lim, Tae-Hoon American Scientific Publishers 2013 Journal of Nanoscience and Nanotechnology Vol.13 No.5
<P>Size-controlled PtRu nanoparticles embedded in WO3 were prepared by simultaneous multigun sputtering on pure targets of Pt, Ru, and WO3. The mean diameter of the PtRu nanoparticles, as confirmed by high-resolution transmission electron microscopy, can be varied from -2.3 to -3.6 nm by varying the RF power ratio of PtRu and WO3. On the basis of transmission electron diffraction results for the PtRu nanoparticles embedded in WO3, it was confirmed that PtRu exists as an alloy metal phase, whereas the WO3 matrix is present as an amorphous phase. Size-controlled PtRu/WO3 electrodes were found to exhibit unique electronic properties depending on their size, which affected the potential of zero total charge and the methanol oxidation reaction. The mass activity of PtRu/WO3 for methanol oxidation was determined by the interplay of the surface electronic factors at the metal-solution interface; the oxophilicity of the nanoparticles increased with decreasing particle size.</P>
( Yung Hyun Choi ),( Ho Sung Kang ),( Mi Ae Yoo ) 생화학분자생물학회 2003 BMB Reports Vol.36 No.2
The product of a tree (Tabebuia avellanedae) from South America, β-lapachone, is known to exhibit various pharmacological properties, the mechanisms of which are poorly understood. The aim of the present study was to further elucidate the possible mechanisms by which p- lapachone exerts its anti-proliferative action in cultured human prostate cancer cells. We observed that the prolieration-inhibitory effect of β-lapachone was due to the induction of apoptosis, which was confirmed by observing the morphological changes and cleavage of the poly(ADP-ribose) polymerase protein. A DNA flow cytometric analysis also revealed that βlapachone arrested the cell cycle progression at the G1 phase. The effects were associated with the down-regulation of the phosphorylation of the retinoblastoma protein (pRB) as well as the enhanced binding of pRB and the transcription factor E2F-1. Also, β-lapachone suppressed the cyclin- dependent kinases(Cdks) and cyclin E-associated kinase activity without changing their expressions. Furthermore, this compound induced the levels of the Cdk inhibitor p21^(WAFI/CIPI) expression in a p-530independent manner, and the p21 proteins that were induced by β-lapachone were associated with Cdk2. β-lapachone also activated the reporter construct of a p21 promoter. Overall, our results demonstrate a combined mechanism that involves the inhibition of pRB phosphorylation and induction of p21 as targets for βlapachone. This may explain some of its anti-cancer effects.