ゼラチンハイドロゲル不織布で作製した人工胆管による胆管再生

京都大学新制・課程博士博士(医学)甲第24289号医博第4905号新制||医||1061(附属図書館)京都大学大学院医学研究科医学専攻(主査)教授 小濱 和貴, 教授 妹尾 浩, 教授 長船 健二学位規則第4条第1項該当Doctor of Medical ScienceKyoto UniversityDFA

Nonlinear polarization evolution using time-dependent density functional theory

We propose a theoretical and computational approach to investigate temporal behavior of a nonlinear polarization in perturbative regime induced by an intense and ultrashort pulsed electric field. First-principles time-dependent density functional theory is employed to describe the electron dynamics. Temporal evolution of third-order nonlinear polarization is extracted from a few calculations of electron dynamics induced by pulsed electric fields with the same time profile but different amplitudes. We discuss characteristic features of the nonlinear polarization evolution as well as an extraction of nonlinear susceptibilities and time delays by fitting the polarization. We also carry out a decomposition of temporal and spatial changes of the electron density in power series with respect to the field amplitude. It helps to get insight into the origin of the nonlinear polarization in atomic scale.Comment: 11 pages, 9 figure

First-principles method for nonlinear light propagation at oblique incidence

We have developed a computational method to describe the nonlinear light propagation of an intense and ultrashort pulse at oblique incidence on a flat surface. In the method, coupled equations of macroscopic light propagation and microscopic electron dynamics are simultaneously solved using a multiscale modeling. The microscopic electronic motion is described by first-principles time-dependent density functional theory. The macroscopic Maxwell equations that describe oblique light propagation are transformed into one-dimensional wave equations. As an illustration of the method, light propagation at oblique incidence on a silicon thin film is presented.Comment: 14 pages, 8 figure

Microstructure of Winged Beans

Microstructures of seven plant introductions of winged beans (Psophocarpus tetragonolobus) produced in Okinawa, Japan were investigated. In cotyledonary cells of winged beans, protein bodies plus numerous lipid bodies were distributed in a cytoplasmic network. Starch granules were often found in some introductions but rarely in others. All seven introductions had very thick cell walls. The high protein, fat and hemicellulose contents of winged beans are consistent with the numerous protein bodies, lipid bodies and thick cell walls in the mature cotyledonary cells. The cell walls contained a number of depressions or cavities 1 to 2 lJ m deep which frequently occurred opposite complementary pits in adjacent cells (presumably pit-pairs). Plasmodesmata traverse the cell walls in the pit-pairs. In order to determine changes during development, cultivar UPS-32 cultivated at Fukuoka-city was used. In coty ledonary cells at 30 days after flowering, cell walls which had pitpairs with plasmodesmata, developing amyloplasts with starch granules, vacuoles with dense flocculent materials, tubular rough endoplasmic reticulum, mitochondria etc., were observed but no protein bodies or lipid bodies were apparent. Protein bodies and lipid bodies were, however, found at 45 days after flowering. Cotyledonary cells at 45 days contained many starch granules but mature seeds contained few, if any

Theoretical investigation of vacancy related defects at 4H-SiC(0001ˉ\bar{1})/SiO2_2 interface after wet oxidation

The stability and formation mechanism of the defects relevant to silicon and carbon vacancies at the 4H-SiC(000$\bar{1}$)/SiO$_2$ interface after wet oxidation are investigated by first-principles calculation based on the density functional theory. The difference in the total energy of the defects agrees with the experimental results concerning the dencity of defects. We found that the characteristic behaviors of the generation of defects are explained by the positions of vacancies and antisites in the SiC(000$\bar{1}$) substrate and that the formation of silicon and carbon vacancies is relevant to the generation mechanism of defects. The generation of silicon and carbon vacancies is attributed to the termination of dangling bonds by H atoms introduced by wet oxidation, resulting in generation of carbon-antisite--carbon-vacancy and divacancies defects in wet oxidation.Comment: 12 page

Valley filters using graphene blister defects from first principles

Valleytronics, which makes use of the two valleys in graphenes, attracts considerable attention and a valley filter is expected to be the central component in valleytronics. We propose the application of the graphene valley filter using blister defects to the investigation of the valley-dependent transport properties of the Stone--Wales and blister defects of graphenes by density functional theory calculations. It is found that the intervalley transition from the $\mathbf{K}$ valley to the $\mathbf{K}^\prime$ valleys is completely suppressed in some defects. Using a large bipartite honeycomb cell including several carbon atoms in a cell and replacing atomic orbitals with molecular orbitals in the tight-binding model, we demonstrate analytically and numerically that the symmetry between the A and B sites of the bipartite honeycomb cell contributes to the suppression of the intervalley transition. In addition, the universal rule for the atomic structures of the blisters suppressing the intervalley transition is derived. Furthermore, by introducing additional carbon atoms to graphenes to form blister defects, we can split the energies of the states at which resonant scattering occurs on the $\mathrm{K}$ and $\mathrm{K}^\prime$ channel electrons. Because of this split, the fully valley-polarized current will be achieved by the local application of a gate voltage.Comment: 19 pages, 15 figure

Optical fractal synthesizer : concept and experimental verification

This paper was published in Optics Express and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://dx.doi.org/10.1364/AO.32.000653 Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law