Ayumu Sugiyama

Impact of UV/O3 treatment on solution-processed amorphous InGaZnO4 thin-film transistors

Ultraviolet–ozone (UV/O3) treatment was adopted to the fabrication of solution-processed amorphous In–Ga–Zn–O thin-film transistors (TFTs), with metal composition of In:Ga:Zn = 1:1:1 represented by InGaZnO4. By applying UV/O3 treatment In–Ga–Zn–O gel films, their condensation was notably enhanced through decomposition of organic- and hydrogen-based elements, which drastically improved the quality of the amorphous InGaZnO4 films. As a result, high TFT performance, with values of on/off ratio, 108; subthreshold swing, 150 mV/decade; threshold voltage, 9.2 V; and field-effect mobility, 5.1 cm2 V−1 s−1, was achieved.

Ab initio study of the polymerisation of cyclopentasilane

The molecular structures and vibration modes of cyclopentasilane (Si5H10) have been examined by employing ab initio and density-functional methods. Three different structures of Si5H10 with different symmetries are analysed, and the results show that the envelope (C s ) and the twist (C2) forms have similar energies and that the planar form (D5h ) is about 50 meV less stable than the C s and C2 forms. The excited-state potential energy surface of Si5H10 is performed using the CIS electronic energy calculation. The ring-open reaction of Si5H10 is investigated in detail by using the first-principles molecular-dynamics simulation for screening the reaction pathways. The formation of Si–H–Si is found to play an important role in the ring-open reaction.

Alternative splicing produces structural and functional changes in CUGBP2

BackgroundCELF/Bruno-like proteins play multiple roles, including the regulation of alternative splicing and translation. These RNA-binding proteins contain two RNA recognition motif (RRM) domains at the N-terminus and another RRM at the C-terminus. CUGBP2 is a member of this family of proteins that possesses several alternatively spliced exons.ResultsThe present study investigated the expression of exon 14, which is an alternatively spliced exon and encodes the first half of the third RRM of CUGBP2. The ratio of exon 14 skipping product (R3δ) to its inclusion was reduced in neuronal cells induced from P19 cells and in the brain. Although full length CUGBP2 and the CUGBP2 R3δ isoforms showed a similar effect on the inclusion of the smooth muscle (SM) exon of the ACTN1 gene, these isoforms showed an opposite effect on the skipping of exon 11 in the insulin receptor gene. In addition, examination of structural changes in these isoforms by molecular dynamics simulation and NMR spectrometry suggested that the third RRM of R3δ isoform was flexible and did not form an RRM structure.ConclusionOur results suggest that CUGBP2 regulates the splicing of ACTN1 and insulin receptor by different mechanisms. Alternative splicing of CUGBP2 exon 14 contributes to the regulation of the splicing of the insulin receptor. The present findings specifically show how alternative splicing events that result in three-dimensional structural changes in CUGBP2 can lead to changes in its biological activity.

All solution-processed amorphous oxide thin-film transistors using UV/O3 treatment

In the fabrication of amorphous oxide thin-film transistors (TFTs) by all-solution process, an ultraviolet–ozone (UV/O3) treatment and solution materials were adopted. By applying the UV/O3 treatment for solution-processed In2−xGaxZnO4 channel layers, enhancement of TFT characteristics was achieved. In particular, the most appropriate metal composition for the In2−xGaxZnO4 system with UV/O3 treatment was found to be x = 1.0. In addition to the channel layers, solution-processed LaNiO3, Bi–Nb–O/La–Ta–O stacked layer, and ITO films were formed as the gate electrode, gate insulator, and source and drain electrodes, respectively, for TFT fabrication. Using UV/O3 treatment and solution materials, all-solution-processed amorphous oxide TFTs were successfully fabricated, and superior TFT properties, including an on–off current ratio of 107, a threshold voltage of 1.6 V, a subthreshold swing of 200 mV/decade, and a field-effect mobility of 0.49 cm2 V−1 s−1, were achieved.

A Method for Opinion Mining of Coffee Service Quality and Customer Value by Mining Twitter

In this work, we focus on customer value of Japanese coffee service by analyzing the huge tweet data set. We suggest the quantitative evaluation method of customer value by using the morphological analysis of the tweets and generated value dictionary. Our suggested methodology can be applied to any service and product to improve the commoditization problem from the viewpoint of service science.

Simulation-based data mining solution to the structure of water surrounding proteins

What is structure of water surrounding proteins remains as one of fundamental unsolved problems of science. Methods in biophysics only provide qualitative description of the structure and thus clarifying the collective phenomena of a huge number of water molecules is still beyond intuition in biophysics. We introduce a simulation-based data mining approach that quantitatively model the structure of water surrounding a protein as clusters of water molecules having similar moving behavior. The paper presents and explains how the advances of AI technique can potentially solve this challenging data-intensive problem.