Browsing by Author "Yu, Jung-Sheng"

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Resistive switching properties of SrZrO(3)-based memory films
(2007-04-01)
Lin, Chun-Chieh
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Lin, Chao-Cheng
;
Tu, Bing-Chung
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Yu, Jung-Sheng
;
Lin, Chen-Hsi
The resistive switching properties of the sputter-deposited SrZrO(3) (SZO) memory films were investigated in this study. The resistive switching behaviors of the SZO film can be improved by doping with vanadium oxide. The conduction mechanisms of the high and low current states of the 0.3% V-doped SZO (V:SZO) film are ohmic conduction and Frenkel-Poole emission, respectively, which implies the bulk effect of the memory film. The resistive ratio of two current states of the 0.3% V:SZO film remains 1000 times after applying 100 voltage sweeping cycles. Furthermore, the 0.3% V:SZO film shows stable resistive switching properties when measurement is performed at 100 degrees C. The band modulation of the SZO/LNO interface is proposed to explain the forming process of the SZO films. The 0.3% V:SZO memory film has excellent properties, such as high stability, good endurance, and long retention time, which make it a good candidate for next-generation nonvolatile memory application.
Stable resistive switching behaviors of sputter deposited V-doped SrZrO3 thin films
(2007-12-03)
Lin, Chun-Chieh
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Yu, Jung-Sheng
;
Lin, Chih-Yang
;
Lin, Chen-Hsi
;
Tseng, Tseung-Yuen
The influences of doping concentration and element on the resistive switching properties of SZO-based memory devices are investigated in this study. The sputter-deposited LNO bottom electrode and SZO resistive layer exhibit (100)-preferred orientation, and the LNO film annealed at 600 degrees C performs smooth surface and high conductivity. The 0.3% V:SZO memory device depicts the good switching behaviors including high resistance ratio, high endurance, long retention time, and non-destructive readout property. The turn-on voltage is slightly dependent on the SZO thickness, while the turn-off voltage is almost irrelative to the thickness. Besides, the switching properties of MoO3-, MoO2-, and Cr2O3-doped SZO devices are also studied. The results demonstrate that the resistive switching is an intrinsic property of the SZO film, but proper doping concentration and element can improve and stabilize the resistive switching behaviors. (C) 2007 Elsevier B.V. All rights reserved.
Sulforaphane Suppresses Hepatitis C Virus Replication by Up-Regulating Heme Oxygenase-1 Expression through PI3K/Nrf2 Pathway
(2016-03-29)
Yu, Jung-Sheng
;
Chen, Wei-Chun
;
Tseng, Chin-Kai
;
Lin, Chun-Kuang
;
Hsu, Yao-Chin
Hepatitis C virus (HCV) infection-induced oxidative stress is a major risk factor for the development of HCV-associated liver disease. Sulforaphane (SFN) is an antioxidant phytocompound that acts against cellular oxidative stress and tumorigenesis. However, there is little known about its anti-viral activity. In this study, we demonstrated that SFN significantly suppressed HCV protein and RNA levels in HCV replicon cells and infectious system, with an IC50 value of 5.7 +/- 0.2 mu M. Moreover, combination of SFN with anti-viral drugs displayed synergistic effects in the suppression of HCV replication. In addition, we found nuclear factor erythroid 2-related factor 2 (Nrf2)/HO-1 induction in response to SFN and determined the signaling pathways involved in this process, including inhibition of NS3 protease activity and induction of IFN response. In contrast, the anti-viral activities were attenuated by knockdown of HO-1 with specific inhibitor (SnPP) and shRNA, suggesting that anti-HCV activity of SFN is dependent on HO-1 expression. Otherwise, SFN stimulated the phosphorylation of phosphoinositide 3-kinase (PI3K) leading Nrf2-mediated HO-1 expression against HCV replication. Overall, our results indicated that HO-1 is essential in SFN-mediated anti-HCV activity and provide new insights in the molecular mechanism of SFN in HCV replication.