Theoretical study of the substituent effects of the equatorial ligands on penta-coordinated trigonal bipyramidal compounds.(Natural Sciences)

論文(Article)We have studied the substituent effect of equatorial ligands of some penta-coordinated trigonal bipyramidal compounds (MX_3Y_2: M=N, P and As; X=H, F, CH_3 and CN; Y=H and F) by using the ab initio molecular orbital method. We divided the whole molecule into two parts i.e. the equatorial part and the apical part, and discussed the stabilization of apical orbitals by drawing the orbital energy correlation diagram. The apical bond stabilization energy is considerably affected through the change of the symmetric apical orbital interaction for fluorine compounds. The substituent effect on HOMO of the equatorial part comes from the antibonding σ-donating interaction between ligand orbital and the lone-pair orbital of the central atom, while LUMO is affected through the σ-type attractive interaction between ligand and ndz^2 orbital of the central atom. The strong substituent effect on LUMO is induced by F through the σ-type interaction. On the other hand π-type effect on HOMO becomes important when CH_3 is introduced to the equatorial part. As the number of CN increases, the antibonding π-type interaction between ligands and the central atom decreases and HOMO of the equatorial part is stabilized. The energy gaps between HOMO and LUMO of nitrogenous compounds are much wider than those of phosphorous and arsenious compounds.departmental bulletin pape

The Minimal English Test : A Preliminary Study

論文(Article)departmental bulletin pape

PI4P-signaling pathway for the synthesis of a nascent membrane structure in selective autophagy

Phosphoinositides regulate a wide range of cellular activities, including membrane trafficking and biogenesis, via interaction with various effector proteins that contain phosphoinositide binding motifs. We show that in the yeast Pichia pastoris, phosphatidylinositol 4′-monophosphate (PI4P) initiates de novo membrane synthesis that is required for peroxisome degradation by selective autophagy and that this PI4P signaling is modulated by an ergosterol-converting PpAtg26 (autophagy-related) protein harboring a novel PI4P binding GRAM (glucosyltransferase, Rab-like GTPase activators, and myotubularins) domain. A phosphatidylinositol-4-OH kinase, PpPik1, is the primary source of PI4P. PI4P concentrated in a protein–lipid nucleation complex recruits PpAtg26 through an interaction with the GRAM domain. Sterol conversion by PpAtg26 at the nucleation complex is necessary for elongation and maturation of the membrane structure. This study reveals the role of the PI4P-signaling pathway in selective autophagy, a process comprising multistep molecular events that lead to the de novo membrane formation

分子軌道法計算プログラムGaussian 03 - その1 -

2006-05departmental bulletin pape

Hydrogen trapping state associated with the low temperature thermal desorption spectroscopy peak in hydrogenated nanostructured graphite

Hydrogenated nanostructured graphite has been reported to exhibit a characteristic peak at around 600–800 K in thermal desorption spectroscopy (TDS). The origin of this peak is still controversial. We have reexamined it based on a combination Fourier transform infrared (FT-IR), electron diffraction, and electron energy-loss spectroscopy (EELS) study. The FT-IR spectrum of HNG exhibited an unknown broad absorption band at very low frequencies around 660 cm^{−1}, which almost disappeared by annealing up to 800 K. Electron diffraction as well as plasmon peaks in EELS detected unusual shrinkage and subsequent expansion of the graphene interlayer distance by hydrogen incorporation and desorption with annealing, which were well correlated with the change in intensity of the 660 cm^{−1} IR band. An energetically stable configuration was found by theoretical model calculations based on GAUSSIAN03. All the present results are consistent with our previous studies, which suggested that hydrogen is loosely trapped between graphene layers.journal articl

分子軌道法計算プログラムGaussian 03 - その7 -

2007-11departmental bulletin pape

分子軌道法計算プログラムGaussian 03 ―その10―

2008-08-29departmental bulletin pape

The Institutional Presidency from a Comparative Perspective: Argentina and Brazil since the 1980s

This paper focuses on the evolution of the institutional presidency - meaning the cluster of agencies that directly support the chief of the executive - in Argentina and Brazil since their redemocratization in the 1980s. It investigates what explains the changes that have come about regarding the size of the institutional presidency and the types of agency that form it. Following the specialized literature, we argue that the growth of the institutional presidency is connected to developments occurring in the larger political system - that is, to the political challenges that the various presidents of the two countries have faced. Presidents adjust the format and mandate of the different agencies under their authority so as to better manage their relations with the political environment. In particular, we argue that the type of government (coalition or single-party) has had consequences for the structure of the presidency or, in other words, that different cabinet structures pose different challenges to presidents. This factor has not played a significant role in presidency-related studies until now, which have hitherto mostly been based on the case of the United States. Our empirical references, the presidencies of Argentina and Brazil, typical cases of coalitional as well as single-party presidentialism respectively allow us to show the impact of the type of government on the number and type of presidential agencies