Ligand-protein docking has been developed and used in facilitating new drug discoveries. In this approach, docking single or multiple small molecules to a receptor site is attempted to find putative ligands. A number of studies have shown that docking algorithms are capable of finding ligands and binding conformations at a receptor site close to experimentally determined structures. These algorithms are expected to be equally applicable to the identification of multiple proteins to which a small molecule can bind or weakly bind. We introduce a ligand-protein inverse-docking approach for finding potential protein targets of a small molecule by the computer-automated docking search of a protein cavity database. This database is developed from protein structures in the Protein Data Bank (PDB). Docking is conducted with a procedure involving multiple-conformer shapematching alignment of a molecule to a cavity followed by molecular-mechanics torsion optimization and energy minimization on both the molecule and the protein residues at the binding region. Scoring is conducted by the evaluation of molecular-mechanics energy and, when applicable, by the further analysis of binding competitiveness against other ligands that bind to the same receptor site in at least one PDB entry. Testing results on two therapeutic agents, 4H-tamoxifen and vitamin E, showed that 50% of the computer-identified potential protein targets were implicated or confirmed by experiments. The application of this approach may facilitate the prediction of unknown and secondary therapeutic target proteins and those related to the side effects and toxicity of a drug or drug candidate.
We have fabricated n-channel 25-nm gate length FinFETs with Schottky-barrier source and drain featuring a selfaligned ytterbium silicide (YbSi 1.8 ). A low-temperature silicidation process was developed for the formation of the low electron barrier height YbSi 1.8 phase, without reaction with SiO 2 isolation or SiN spacer materials, enabling integration in a CMOS fabrication process flow. The fabricated device exhibits good device characteristics with a drive current of 241 µA/µm at V DS = V GS − V t = 1 V, I on /I off = 10 4 at V DS = 1.1 V, subthreshold swing of 125 mV/decade, and drain-induced barrier lowering of 0.26 V/V.
The miniaturization of future electronic devices requires the knowledge of interfacial properties between two-dimensional channel materials and high-κ dielectrics in the limit of one atomic layer thickness. In this report, by combining particle-swarm optimization method with first-principles calculations, we present a detailed study of structural, electronic, mechanical, and dielectric properties of Al2O3 monolayer. We predict that planar Al2O3 monolayer is globally stable with a direct band gap of 5.99 eV and thermal stability up to 1100 K. The stability of this high-κ oxide monolayer can be enhanced by substrates such as graphene, for which the interfacial interaction is found to be weak. The band offsets between the Al2O3 monolayer and graphene are large enough for electronic applications. Our results not only predict a stable high-κ oxide monolayer, but also improve the understanding of interfacial properties between a high-κ dielectric monolayer and two-dimensional material.
A new pyramidal structural defect, 5 to 8 micron wide, has been discovered in
thin films of epitaxial erbium disilicide formed by annealing thin Er films on
Si(001) substrates at temperatures of 500 to 800C. Since these defects form
even upon annealing in vacuum of TiN-capped films their formation is not due to
oxidation. The pyramidal defects are absent when the erbium disilicide forms on
amorphous substrates, which suggests that epitaxial strains play an important
role in their formation. We propose that these defects form as a result of the
separation of the silicide film from the substrate and its buckling in order to
relieve the compressive, biaxial epitaxial stresses. Silicon can then diffuse
through the silicide or along the interface to fully or partially fill the void
between the buckled erbium disilicide film and the substrate.Comment: 14 pages, 5 figures. Submitted to Applied Physics Letter
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