Tokyo, Japan
Tokyo, Japan

The Gakushūin or Peers School , also known as Gakushūjo, is a Japanese educational institution originally established to educate the children of Japan's nobility. Wikipedia.

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Sun K.,University of Maryland University College | Gu Z.,University of California at Santa Barbara | Katsura H.,Gakushuin University | Das Sarma S.,University of Maryland University College
Physical Review Letters | Year: 2011

We report the theoretical discovery of a class of 2D tight-binding models containing nearly flatbands with nonzero Chern numbers. In contrast with previous studies, where nonlocal hoppings are usually required, the Hamiltonians of our models only require short-range hopping and have the potential to be realized in cold atomic gases. Because of the similarity with 2D continuum Landau levels, these topologically nontrivial nearly flatbands may lead to the realization of fractional anomalous quantum Hall states and fractional topological insulators in real materials. Among the models we discover, the most interesting and practical one is a square-lattice three-band model which has only nearest-neighbor hopping. To understand better the physics underlying the topological flatband aspects, we also present the studies of a minimal two-band model on the checkerboard lattice. © 2011 American Physical Society.

Mori K.,Gakushuin University | Wakazawa M.,Gakushuin University | Akiyama T.,Gakushuin University
Chemical Science | Year: 2014

We describe herein a chiral phosphoric acid catalyzed Friedel-Crafts reaction of indoles with β-alkoxycarbonyl-β-disubstituted nitroalkenes. A wide variety of substrates participated in this reaction to afford indoles having all-carbon quaternary centers with excellent selectivities (up to 97% ee). Further investigation suggested that the olefin geometry and the employment of NH-indole derivatives are responsible for both reactivity and selectivity. © 2014 the Partner Organisations.

Mori K.,Gakushuin University | Sueoka S.,Gakushuin University | Akiyama T.,Gakushuin University
Journal of the American Chemical Society | Year: 2011

Described herein is the first example of an aliphatic, nonbenzylic hydride shift/cyclization sequence that contains two types of novel sp 3-C-H functionalization: (1) construction of a tetraline skeleton via [1,5]-hydride shift/cyclization and (2) [1,6]-hydride shift/cyclization to form a five-membered ring (indane derivatives). © 2011 American Chemical Society.

Tasaki H.,Gakushuin University
Physical Review Letters | Year: 2013

In a system of interacting f=1 bosons (in the subspace where the total spin in the z direction is vanishing), we prove inequalities for the ground state expectation value of the density of spin-0 bosons. The inequalities imply that the ground state possesses "polar" or "antiferromagnetic" order when the quadratic Zeeman term q is large enough. In the low density limit, the inequalities establish the existence of a sharp transition at q=0 when q is varied. © 2013 American Physical Society.

Katsura H.,Gakushuin University | Tasaki H.,Gakushuin University
Physical Review Letters | Year: 2013

We prove basic theorems about the ground states of the S=1 Bose-Hubbard model. The results are quite universal and depend only on the coefficient U 2 of the spin-dependent interaction. We show that the ground state exhibits saturated ferromagnetism if U2<0, is spin-singlet if U2>0, and exhibits "SU(3)-ferromagnetism" if U 2=0, and completely determine the degeneracy in each region. © 2013 American Physical Society.

Sato S.,Gakushuin University | Nakamura H.,Gakushuin University
Angewandte Chemie - International Edition | Year: 2013

A photocatalyst ([Ru(bpy)3]2+) bound to a protein ligand was essential for the title method. Local single-electron transfer from the catalyst resulted in the formation of tyrosyl radicals. N′-Acetyl-N,N- dimethyl-1,4-phenylenediamine was used as the tyrosyl radical trapping agent and used in a radical addition to afford selective modification of the target protein. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Saito K.,Gakushuin University | Kajiwara Y.,Gakushuin University | Akiyama T.,Gakushuin University
Angewandte Chemie - International Edition | Year: 2013

A good mix: The title reaction of o-alkynylacetophenones with the Hantzsch ester in the presence of a chiral copper/phosphate catalyst proceeds in good yields with excellent enantioselectivities. The key intermediate for enantiocontrol is the ion pair of the carbonyl ylide with a chiral phosphate anion, and this process provides straight forward access to highly enantioriched chiral isochromenes. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Nakano F.,Gakushuin University
Journal of Statistical Physics | Year: 2014

We study the level statistics for two classes of 1-dimensional random Schrödinger operators: (1) for operators whose coupling constants decay as the system size becomes large, and (2) for operators with critically decaying random potential. As a byproduct of (2) with our previous result (Kotani and Nakano in Festschrift Masatoshi Fukushima, 2013) imply the coincidence of the limits of circular and Gaussian beta ensembles. © 2014 Springer Science+Business Media New York.

Recent development of boron cluster lipids and their liposomal boron delivery system (BDS) are summarized in this article. Boron compounds used in boron neutron capture therapy (BNCT) are, in general, nontoxic unless neutron capture reaction of boron takes place. Therefore, the boron compounds accumulated into other organs would not cause such side effects for patient. Selective and sufficient delivery of boron-10 to tumor results in the successful BNCT. There are two approaches for BDS: encapsulation of boron compounds into liposomes and incorporation of boron-conjugated lipids into the liposomal bilayer, both of which have been significantly investigated. The combination of both approaches displayed potency and, hence, the ability to reduce the total dose of liposomes without reducing the efficacy of BNCT. Boron compounds that have no affinity to tumor can potentially be delivered to tumor tissues by liposomes, therefore, liposomal BDS would be one of the most attractive approaches for efficient BNCT of various cancers. © 2013 Future Science Ltd.

Sugiishi T.,Gakushuin University | Nakamura H.,Gakushuin University
Journal of the American Chemical Society | Year: 2012

The zinc(II)-catalyzed redox cross-dehydrogenative coupling (CDC) of propargylic amines and terminal alkynes proceeds to afford N-tethered 1,6-enynes. In the current CDC reaction, a C(sp)-C(sp 3) bond is formed between the carbon adjacent to the nitrogen atom in the propargylic amine and the terminal carbon of the alkyne with reduction of the C-C triple bond of the propargylic amine, which acts as an internal oxidant. © 2012 American Chemical Society.

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