Tsutomu Kobayashi

Large scale evolution of the curvature perturbation in Horava-Lifshitz cosmology (2009)

Kobayashi, Tsutomu, Urakawa, Yuko, Yamaguchi, Masahide

In the non-relativistic theory of gravity recently proposed by Horava, the Hamiltonian constraint is not satisfied locally at each point in space. The absence of the local Hamiltonian constraint...

Breaking the scale invariance of the primordial power spectrum in Horava-Lifshitz Cosmology (2009)

Yamamoto, Kazuhiro, Kobayashi, Tsutomu, Nakamura, Gen

We study the spectral tilt of primordial perturbations in Horava-Lifshitz cosmology. The uniform approximation, which is a generalization of the familiar Wentzel-Kramers-Brillouin (WKB) method, is...

A note on observational signatures in superluminal unified dark matter models (2009)

Urakawa, Yuko, Kobayashi, Tsutomu

We explore the possibility that the dark matter and dark energy are mimicked by a single fluid or by a single $k$-essence-like scalar field. The so called Chaplygin gas unified dark matter models can...

Cluster formation and the Sunyaev-Zel'dovich power spectrum in modified gravity: the case of a phenomenologically extended DGP model (2009)

Kobayashi, Tsutomu, Tashiro, Hiroyuki

We investigate the effect of modified gravity on cluster abundance and the Sunyaev-Zel'dovich angular power spectrum. Our modified gravity is based on a phenomenological extension of the...

Gravitational waves from p-form inflation (2009)

Kobayashi, Tsutomu, Yokoyama, Shuichiro

Recently it was shown that an inflationary background can be realized by any $p$-form field non-minimally coupled to gravity. In this paper, we study gravitational waves generated during p-form...

Can higher curvature corrections cure the singularity problem in f(R) gravity? (2008)

Kobayashi, Tsutomu, Maeda, Kei-ichi

Although $f(R)$ modified gravity models can be made to satisfy solar system and cosmological constraints, it has been shown that they have the serious drawback of the nonexistence of stars with...

Relativistic stars in f(R) gravity, and absence thereof (2008)

Kobayashi, Tsutomu, Maeda, Kei-ichi

Several f(R) modified gravity models have been proposed which realize the correct cosmological evolution and satisfy solar system and laboratory tests. Although nonrelativistic stellar configurations...

UV caps, IR modification of gravity, and recovery of 4D gravity in regularized braneworlds (2008)

Kobayashi, Tsutomu

In the context of six-dimensional conical braneworlds we consider a simple and explicit model that incorporates long distance modification of gravity and regularization of codimension-2...

Primordial magnetic fields from second-order cosmological perturbations: Tight coupling approximation (2008)

Maeda, Satoshi, Kitagawa, Satoshi, Kobayashi, Tsutomu, Shiromizu, Tetsuya

We explore the possibility of generating large-scale magnetic fields from second-order cosmological perturbations during the pre-recombination era. The key process for this is Thomson scattering...

Quasinormal modes of black holes localized on the Randall-Sundrum 2-brane (2008)

Nozawa, Masato, Kobayashi, Tsutomu

We investigate conformal scalar, electromagnetic, and massless Dirac quasinormal modes of a brane-localized black hole. The background solution is the four-dimensional black hole on a 2-brane that...

Curvature corrections to the low energy effective theory in 6D regularized braneworlds (2008)

Kobayashi, Tsutomu, Shiromizu, Tetsuya, De Rham, Claudia

We study the effective gravitational theory on a brane in a six-dimensional Einstein-Maxwell model of flux compactification, regularizing a conical defect as a codimension-one brane. We employ the...

Bulk scalar emission from a rotating black hole pierced by a tense brane (2007)

Kobayashi, Tsutomu, Nozawa, Masato, Takamizu, Yu-ichi

We study the emission of scalar fields into the bulk from a six-dimensional rotating black hole pierced by a 3-brane. We determine the angular eigenvalues in the presence of finite brane tension by...

Low energy effective theory on a regularized brane in 6D gauged chiral supergravity (2007)

Arroja, Frederico, Kobayashi, Tsutomu, Koyama, Kazuya, Shiromizu, Tetsuya

We derive the low energy effective theory on a brane in six-dimensional chiral supergravity. The conical 3-brane singularities are resolved by introducing cylindrical codimension one 4-branes whose...

Low energy effective theory on a regularized brane in six-dimensional flux compactifications (2007)

Fujii, Shunsuke, Kobayashi, Tsutomu, Shiromizu, Tetsuya

Conical brane singularities in six-dimensional flux compactification models can be resolved by introducing cylindrical codimension-one branes with regular caps instead of 3-branes (a la Kaluza-Klein...

スポーツが触発する国民意識への新たなモメント - 南太平洋で展開されるFIFAのサッカー振興の事例から - (2007)

小林, 勉, KOBAYASHI, Tsutomu

The number of IOC and IF member countries exceeds that of UN member countries. Therefore these organizations have the merit of being able to integrate the developed and developing countries on a...

Hybrid compactifications and brane gravity in six dimensions (2007)

Kobayashi, Tsutomu, Takamizu, Yu-ichi

We consider a six-dimensional axisymmetric Einstein-Maxwell model of warped braneworlds. The bulk is bounded by two branes, one of which is a conical 3-brane and the other is a 4-brane wrapped around...

Brane cosmological solutions in six-dimensional warped flux compactifications (2007)

Kobayashi, Tsutomu, Minamitsuji, Masato

We study cosmology on a conical brane in the six-dimensional Einstein-Maxwell-dilaton system, where the extra dimensions are compactified by a magnetic flux. We systematically construct exact...

Immunochemotherapy of gastric cancer with levamisole. (2007)

Miwa, Hiroaki, Ono, Fumio, Moriyama, Minoru, Kobayashi, Tsutomu, Oka, Tetsuhide, Nakamura, Kenji, ...

In 156 cases of gastric cancer, levamisole (LMS) was administered at a daily dose of 150 mg for three consecutive days every other week. The administration was started 3 days before operation. This...

Gravity on an extended brane in six-dimensional warped flux compactifications (2007)

Kobayashi, Tsutomu, Minamitsuji, Masato

We study linearized gravity in a six-dimensional Einstein-Maxwell model of warped braneworlds, where the extra dimensions are compactified by a magnetic flux. It is difficult to construct a strict...

Cosmological magnetic fields from nonlinear effects (2007)

Kobayashi, Tsutomu, Maartens, Roy, Shiromizu, Tetsuya, Takahashi, Keitaro

In the standard cosmological model, magnetic fields and vorticity are generated during the radiation era via second-order density perturbations. In order to clarify the complicated physics of this...

Scalar cosmological perturbations in the Gauss-Bonnet braneworld (2006)

Kobayashi, Tsutomu, Minamitsuji, Masato

We study scalar cosmological perturbations in a braneworld model with a bulk Gauss-Bonnet term. For an anti-de Sitter bulk, the five-dimensional perturbation equations share the same form as in the...

Low energy effective gravitational equations on a Gauss-Bonnet brane (2006)

Kobayashi, Tsutomu, Shiromizu, Tetsuya, Deruelle, Nathalie

We present effective gravitational equations at low energies in a $Z_2$-symmetric braneworld with the Gauss-Bonnet term. Our derivation is based on the geometrical projection approach, and we solve...

On asymptotic behavior of anisotropic Dvali-Gabadadze-Porrati branes (2006)

Kobayashi, Tsutomu

The braneworld model of Dvali-Gabadadze-Porrati (DGP) provides an interesting alternative to a positive cosmological constant by modifying gravity at large distances. We investigate the asymptotic...

Holographic entanglement entropy of de Sitter braneworld (2006)

Iwashita, Yukinori, Kobayashi, Tsutomu, Shiromizu, Tetsuya, Yoshino, Hirotaka

We study the holographic representation of the entanglement entropy, recently proposed by Ryu and Takayanagi, in a braneworld context. The holographic entanglement entropy of a de Sitter brane...

Initial Kaluza-Klein fluctuations and inflationary gravitational waves in braneworld cosmology (2006)

Kobayashi, Tsutomu

We study the spectrum of gravitational waves generated from inflation in the Randall-Sundrum braneworld. Since the inflationary gravitational waves are of quantum-mechanical origin, the initial...

The spectrum of gravitational waves in Randall-Sundrum braneworld cosmology (2005)

Kobayashi, Tsutomu, Tanaka, Takahiro

We study the generation and evolution of gravitational waves (tensor perturbations) in the context of Randall-Sundrum braneworld cosmology. We assume that the initial and final stages of the...

Quantum-mechanical generation of gravitational waves in braneworld (2005)

Kobayashi, Tsutomu, Tanaka, Takahiro

We study the quantum-mechanical generation of gravitational waves during inflation on a brane embedded in a five-dimensional anti-de Sitter bulk. To make the problem well-posed, we consider the setup...

A Vaidya-type radiating solution in Einstein-Gauss-Bonnet gravity and its application to braneworld (2005)

Kobayashi, Tsutomu

We consider a Vaidya-type radiating spacetime in Einstein gravity with the Gauss-Bonnet combination of quadratic curvature terms. Simply generalizing the known static black hole solutions in...

Leading order corrections to the cosmological evolution of tensor perturbations in braneworld (Short version) (2005)

Kobayashi, Tsutomu, Tanaka, Takahiro

Tensor perturbations in an expanding braneworld of the Randall Sundrum type are investigated. We consider a model composed of a slow-roll inflation phase and the succeeding radiation phase. The...

Five-dimensional black strings in Einstein-Gauss-Bonnet gravity (2004)

Kobayashi, Tsutomu, Tanaka, Takahiro

We consider black-string-type solutions in five-dimensional Einstein-Gauss-Bonnet gravity. Numerically constructed solutions under static, axially symmetric and translationally invariant metric...

Leading order corrections to the cosmological evolution of tensor perturbations in braneworld (2004)

Kobayashi, Tsutomu, Tanaka, Takahiro

Tensor type perturbations in the expanding brane world of the Randall Sundrum type are investigated. We consider a model composed of slow-roll inflation phase and the succeeding radiation phase. The...

Bulk inflaton shadows of vacuum gravity (2003)

Kobayashi, Tsutomu, Tanaka, Takahiro

We introduce a $(5+m)$-dimensional vacuum description of five-dimensional bulk inflaton models with exponential potentials that makes analysis of cosmological perturbations simple and transparent. We...

Primordial gravitational waves in inflationary braneworld (2003)

Kobayashi, Tsutomu, Kudoh, Hideaki, Tanaka, Takahiro

We study primordial gravitational waves from inflation in Randall-Sundrum braneworld model. The effect of small change of the Hubble parameter during inflation is investigated using a toy model given...

Effects on Extrahepatic UDP-Glucuronosyltransferases in Hypophysectomized Rat (2002)

Yokota, Hiroshi, Kunimasa, Yohko, Shimoyama, Yasuko, Kobayashi, Tsutomu, Matsumoto, Junya, Yuasa, Akira

The effects of hypophysectomy on hepatic and extrahepatic UDP-glucuronosyltrans-ferase activities in adult male rats were observed. UDP-glucuronosyltransferase activities toward 1-naphthol decreased...

Critical role of Rho-kinase pathway for cardiac performance and remodeling in failing rat hearts (2002)

Kobayashi, Naohiko, Horinaka, Shigeo, Mita, Shin-ichiro, Nakano, Shigefumi, Honda, Takeaki, Yoshida, Kohtaro, ...

Objectives: Rho and Rho-kinase play a critical role in the regulation of cellular functions such as proliferation and migration. To elucidate the molecular mechanisms that regulate cardiac function...

Glial expression of Borna disease virus phosphoprotein induces behavioral and neurological abnormalities in transgenic mice

Kamitani, Wataru, Ono, Etsuro, Yoshino, Saori, Kobayashi, Tsutomu, Taharaguchi, Satoshi, Lee, Byeong-Jae, ...

One hypothesis for the etiology of behavioral disorders is that infection by a virus induces neuronal cell dysfunctions resulting in a wide range of behavioral abnormalities. However, a direct...

Effect of Dilution Rate on Metabolic Pathway Shift between Aceticlastic and Nonaceticlastic Methanogenesis in Chemostat Cultivation

Shigematsu, Toru, Tang, Yueqin, Kobayashi, Tsutomu, Kawaguchi, Hiromi, Morimura, Shigeru, Kida, Kenji

Acetate conversion pathways of methanogenic consortia in acetate-fed chemostats at dilution rates of 0.025 and 0.6 day−1 were investigated by using 13C-labeled acetates, followed by gas...

Glial expression of Borna disease virus phosphoprotein induces behavioral and neurological abnormalities in transgenic mice

Kamitani, Wataru, Ono, Etsuro, Yoshino, Saori, Kobayashi, Tsutomu, Taharaguchi, Satoshi, Lee, Byeong-Jae, ...

One hypothesis for the etiology of behavioral disorders is that infection by a virus induces neuronal cell dysfunctions resulting in a wide range of behavioral abnormalities. However, a direct...

Effect of Dilution Rate on Metabolic Pathway Shift between Aceticlastic and Nonaceticlastic Methanogenesis in Chemostat Cultivation

Shigematsu, Toru, Tang, Yueqin, Kobayashi, Tsutomu, Kawaguchi, Hiromi, Morimura, Shigeru, Kida, Kenji

Acetate conversion pathways of methanogenic consortia in acetate-fed chemostats at dilution rates of 0.025 and 0.6 day−1 were investigated by using 13C-labeled acetates, followed by gas...

Molecular and functional characterization of microsomal UDP-glucuronic acid uptake by members of the nucleotide sugar transporter (NST) family

Kobayashi, Tsutomu, Sleeman, Judith E., Coughtrie, Michael W. H., Burchell, Brian

Transport of the co-substrate UDPGA (UDP-glucuronic acid) into the lumen of the endoplasmic reticulum is an essential step in glucuronidation reactions due to the intraluminal location of the...

Efficacy of SPK-843, a Novel Polyene Antifungal, in Comparison with Amphotericin B, Liposomal Amphotericin B, and Micafungin against Murine Pulmonary Aspergillosis▿

Kakeya, Hiroshi, Miyazaki, Yoshitsugu, Senda, Hisato, Kobayashi, Tsutomu, Seki, Masafumi, Izumikawa, Koichi, ...

SPK-843, a new polyene antifungal, exhibited dose-dependent efficacy on murine pulmonary aspergillosis models. SPK-843 doses of higher than 1.0 mg/kg of body weight exhibited no renal toxicities and...

Efficacy of SPK-843, a Novel Polyene Antifungal, in a Murine Model of Systemic Cryptococcosis▿

Kakeya, Hiroshi, Miyazaki, Yoshitsugu, Senda, Hisato, Kobayashi, Tsutomu, Seki, Masafumi, Izumikawa, Koichi, ...

SPK-843, a new polyene antifungal, possessed efficacy in a murine model of systemic infection caused by Cryptococcus neoformans. The administration of 4.0 mg/kg SPK-843 led to better survival...

Selective and direct inhibition of TRPC3 channels underlies biological activities of a pyrazole compound

Kiyonaka, Shigeki, Kato, Kenta, Nishida, Motohiro, Mio, Kazuhiro, Numaga, Takuro, Sawaguchi, Yuichi, ...

Canonical transient receptor potential (TRPC) channels control influxes of Ca2+ and other cations that induce diverse cellular processes upon stimulation of plasma membrane receptors coupled to...