2,931 research outputs found

    Analysis of hydrogen induced failure by hydrogen injection methods in micro- alloyed steels

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    Competition between structural distortion and magnetic moment formation in fullerene C20_{20}

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    We investigated the effect of on-site Coulomb interactions on the structural and magnetic ground state of the fullerene C20_{20} based on density-functional-theory calculations within the local density approximation plus on-site Coulomb corrections (LDA+UU). The total energies of the high symmetry (IhI_{h}) and distorted (D3dD_{3d}) structures of C20_{20} were calculated for different spin configurations. The ground state configurations were found to depend on the forms of exchange-correlation potentials and the on-site Coulomb interaction parameter UU, reflecting the subtle nature of the competition between Jahn-Teller distortion and magnetic instability in fullerene C20_{20}. While the non-magnetic state of the distorted D3dD_{3d} structure is robust for small UU, a magnetic ground state of the undistorted IhI_{h} structure emerges for UU larger than 4 eV when the LDA exchange-correlation potential is employed.Comment: 4 figures, 1 tabl

    Structural and optical properties of ZnO nanorods by electrochemical growth using multi-walled carbon nanotube-composed seed layers

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    We reported the enhancement of the structural and optical properties of electrochemically synthesized zinc oxide [ZnO] nanorod arrays [NRAs] using the multi-walled carbon nanotube [MWCNT]-composed seed layers, which were formed by spin-coating the aqueous seed solution containing MWCNTs on the indium tin oxide-coated glass substrate. The MWCNT-composed seed layer served as the efficient nucleation surface as well as the film with better electrical conductivity, thus leading to a more uniform high-density ZnO NRAs with an improved crystal quality during the electrochemical deposition process. For ZnO NRAs grown on the seed layer containing MWCNTs (2 wt.%), the photoluminescence peak intensity of the near-band-edge emission at a wavelength of approximately 375 nm was enhanced by 2.8 times compared with that of the ZnO nanorods grown without the seed layer due to the high crystallinity of ZnO NRAs and the surface plasmon-meditated emission enhancement by MWCNTs. The effect of the MWCNT-composed seed layer on the surface wettability was also investigated

    Restructuring TCAD System: Teaching Traditional TCAD New Tricks

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    Traditional TCAD simulation has succeeded in predicting and optimizing the device performance; however, it still faces a massive challenge - a high computational cost. There have been many attempts to replace TCAD with deep learning, but it has not yet been completely replaced. This paper presents a novel algorithm restructuring the traditional TCAD system. The proposed algorithm predicts three-dimensional (3-D) TCAD simulation in real-time while capturing a variance, enables deep learning and TCAD to complement each other, and fully resolves convergence errors.Comment: In Proceedings of 2021 IEEE International Electron Devices Meeting (IEDM

    Quality indicators in esophagogastroduodenoscopy

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    Esophagogastroduodenoscopy (EGD) has been used to diagnose a wide variety of upper gastrointestinal diseases. In particular, EGD is used to screen high-risk subjects of gastric cancer. Quality control of EGD is important because the diagnostic rate is examiner-dependent. However, there is still no representative quality indicator that can be uniformly applied in EGD. There has been growing awareness of the importance of quality control in improving EGD performance. Therefore, we aimed to review the available and emerging quality indicators for diagnostic EGD

    CK2 Is the Regulator of SIRT1 Substrate-Binding Affinity, Deacetylase Activity and Cellular Response to DNA-Damage

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    SIRT1, an NAD+ (nicotinamide adenine dinucleotide)-dependent deacetylase, protects cells from stress-induced apoptosis, and its orthologues delay aging in lower eukaryotes. SIRT1 increases survival in response to stress such as DNA damage by deacetylating a number of substrates including pro-apoptotic protein p53. The molecular mechanism by which DNA-damage activates SIRT1 is not known. By screening a kinase inhibitor library, we identified CK2 as a SIRT1 kinase. CK2 is a pleiotropic kinase with more than 300 substrates and well-known anti-apoptotic and pro-growth activities. We find that CK2 is recruited to SIRT1 after ionizing radiation (IR) and phosphorylates conserved residues Ser 154, 649, 651 and 683 in the N- and C-terminal domains of mouse SIRT1. Phosphorylation of SIRT1 increases its deacetylation rate but not if the four Ser residues are mutated. In addition, phosphorylation of SIRT1 increases its substrate-binding affinity. CK2-mediated phosphorylation increases the ability of SIRT1 to deacetylate p53 and protect cells from apoptosis after DNA damage. Based on these findings, we propose that CK2 protects against IR-induced apoptosis partly by phosphorylating and activating SIRT1. Thus, this work suggests that SIRT1 is a component of the expansive anti-apoptotic network controlled by CK2. Since expression of both CK2 and SIRT1 is upregulated with tumorigenesis and downregulated with senescence, the CK2-SIRT1 link sheds new light on how CK2 may regulate cancer development and aging
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