Pusan National University

About: Pusan National University is a education organization based out in Busan, South Korea. It is known for research contribution in the topics: Catalysis & Population. The organization has 24124 authors who have published 45054 publications receiving 819356 citations. The organization is also known as: Busan National University & Pusan University.

Expression of DNA Methyltransferase 1 Is Activated by Hepatitis B Virus X Protein via a Regulatory Circuit Involving the p16INK4a-Cyclin D1-CDK 4/6-pRb-E2F1 Pathway

Abstract: DNA methyltransferase 1 (DNMT1) is responsible for copying DNA methylation patterns to the daughter strands during DNA replication Its expression is frequently up-regulated in human tumors, including hepatocellular carcinoma, but the mechanism of overexpression and its biological significance remain unclear Here, we show that hepatitis B virus X protein (HBx) activates DNMT1 expression via a regulatory circuit involving the p16(INK4a)-cyclin D1-cyclin-dependent kinase (CDK) 4/6-retinoblastoma protein (pRb)-E2F1 pathway HBx induced DNA hypermethylation of p16(INK4a) promoter to repress its expression, which subsequently led to activation of G1-CDKs, phosphorylation of pRb, activation of E2F1, and finally transcriptional activation of DNMT1 Inhibition of DNMT1 activity by either treatment with 5'-Aza-2'dC or introduction of DNMT1 small interfering RNA not only abolished the DNA methylation-mediated p16(INK4a) repression but also impaired DNMT1 expression itself, suggesting a cross-talk between DNMT1 and p16(INK4a) The up-regulation of cyclin D1 by HBx is likely to serve as an initiative impulse for the circuit because it was absolutely required for the activation of DNMT1 expression We also observed that accumulated DNMT1 via this pathway inactivates E-cadherin expression through promoter hypermethylation Considering that the pRb-E2F1 pathway is commonly activated in human tumors, activation of this circuit might be widespread and a potential therapeutic target

A High Efficiency Nonfullerene Organic Solar Cell with Optimized Crystalline Organizations.

Abstract: A well-organized donor-acceptor crystalline structure is examined for high -performance nonfullerene solar cells. By thermal annealing, nanoscale structures of both donor and acceptor domains are successfully modulated, followed by -significant changes in the resulting -photovoltaic characteristics. When annealed at 90 °C, a maximum power conversion efficiency of 7.64% with a -remarkable open-circuit voltage of 1.03 V is obtained.

Parameter-free effective field theory calculation for the solar proton-fusion and hep processes

Abstract: Spurred by the recent complete determination of the weak currents in two-nucleon systems up to $\mathcal{O}{(Q}^{3})$ in heavy-baryon chiral perturbation theory, we carry out a parameter-free calculation of the threshold S factors for the solar $\mathrm{pp}$ (proton-fusion) and hep processes in an effective field theory (EFT) that combines the merits of the standard nuclear physics method and systematic chiral expansion. The power of the EFT adopted here is that one can correlate in a unified formalism the weak-current matrix elements of two-, three-, and four-nucleon systems. Using the tritium $\ensuremath{\beta}$-decay rate as an input to fix the only unknown parameter in the theory, we can evaluate the threshold S factors with drastically improved precision; the results are ${S}_{\mathrm{pp}}(0)=3.94\ifmmode\times\else\texttimes\fi{}(1\ifmmode\pm\else\textpm\fi{}0.004)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}25}\mathrm{MeV}\mathrm{}\mathrm{b}$ and ${S}_{\mathrm{hep}}(0)=(8.6\ifmmode\pm\else\textpm\fi{}1.3)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}20}\mathrm{keV}\mathrm{}\mathrm{b}.$ The dependence of the calculated S factors on the momentum cutoff parameter $\ensuremath{\Lambda}$ has been examined for a physically reasonable range of $\ensuremath{\Lambda}.$ This dependence is found to be extremely small for the $\mathrm{pp}$ process, and to be within acceptable levels for the hep process, substantiating the consistency of our calculational scheme.