79 results on '"Isao Maruyama"'
Search Results
2. Electronic Density of States in CeSi2−x Studied by Point-Contact Spectroscopy
- Author
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Takuya Takahashi, Tsubasa Teramoto, Masanobu Shiga, Isao Maruyama, Keisuke Ida, Kousei Ishiwatari, Masashi Ohashi, and Tatsuya Kawae
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- 2023
3. Flat-band solutions in $D$-dimensional decorated diamond and pyrochlore lattices: Reduction to molecular problem
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Yasuhiro Hatsugai, Tomonari Mizoguchi, Isao Maruyama, and Hosho Katsura
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Physics ,Condensed Matter - Materials Science ,Condensed matter physics ,Condensed Matter - Mesoscale and Nanoscale Physics ,Strongly Correlated Electrons (cond-mat.str-el) ,Pyrochlore ,Diamond ,Materials Science (cond-mat.mtrl-sci) ,FOS: Physical sciences ,Crystal structure ,engineering.material ,law.invention ,Condensed Matter - Strongly Correlated Electrons ,law ,Dispersion relation ,Line graph ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,engineering ,Variety (universal algebra) ,Wave function ,Realization (systems) - Abstract
Flat-band models have been of particular interest from both fundamental aspects and realization in materials. Beyond the canonical examples such as Lieb lattices and line graphs, a variety of tight-binding models are found to possess flat bands. However, analytical treatment of dispersion relations is limited, especially when there are multiple flat bands with different energies. In this paper, we present how to determine flat-band energies and wave functions in tight-binding models on decorated diamond and pyrochlore lattices in generic dimensions $D \geq 2$. For two and three dimensions, such lattice structures are relevant to various organic and inorganic materials, and thus our method will be useful to analyze the band structures of these materials., Comment: 13 pages, 10 figures
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- 2021
- Full Text
- View/download PDF
4. Chlorella supplementation decreases methylmercury concentrations of hair and blood in healthy volunteers
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Isao Maruyama, Akira Yasutake, Takuya Uchikawa, Toshihiro Kanno, Yotaro Ando, and Hisao Kitsuki
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biology ,Chemistry ,chemistry.chemical_element ,04 agricultural and veterinary sciences ,010501 environmental sciences ,biology.organism_classification ,040401 food science ,01 natural sciences ,Mercury (element) ,Chlorella ,chemistry.chemical_compound ,0404 agricultural biotechnology ,Healthy volunteers ,Food science ,Methylmercury ,0105 earth and related environmental sciences - Published
- 2018
5. Storing-hydrogen processes on graphene activated by atomic-vacancies
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Isao Maruyama, Gagus Ketut Sunnardianto, and Koichi Kusakabe
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Hydrogen ,Renewable Energy, Sustainability and the Environment ,Chemistry ,Graphene ,Cryo-adsorption ,Energy Engineering and Power Technology ,chemistry.chemical_element ,02 engineering and technology ,Hydrogen atom ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Reversible reaction ,law.invention ,Fuel Technology ,Adsorption ,Chemical physics ,law ,Desorption ,0103 physical sciences ,Density functional theory ,Atomic physics ,010306 general physics ,0210 nano-technology - Abstract
We investigated the minimum energy pathways and energy barriers of reversible reaction (V111 + H2↔V221) based upon calculations using density functional theory. We find a comparable activation barrier of around 1.3 eV for both the dissociative chemisorption and desorption processes. The charge transfer rate from a reacting hydrogen atom to the graphene is around 0.18 e per hydrogen atom in the final state. A subsequent reaction path to recover the initial structure of V111 is realized by the migration of hydrogen atoms from V221 onto the graphene surface. The comparable energy barrier of 1.3 eV for both adsorption and desorption suggests that this novel storage and release concept has the potential to act as a hydrogen storage system for certain applications.
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- 2017
6. Systematic Study of the Effect of H Adsorption on the Electron-Transfer Rate in Graphene
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Koichi Kusakabe, Isao Maruyama, and Gagus Ketut Sunnardianto
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Imagination ,Thesaurus (information retrieval) ,Chemical substance ,Materials science ,Graphene ,media_common.quotation_subject ,Nanotechnology ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,law.invention ,Electron transfer rate ,Computational Mathematics ,Search engine ,Adsorption ,law ,General Materials Science ,Electrical and Electronic Engineering ,0210 nano-technology ,Science, technology and society ,media_common - Published
- 2016
7. Dissociation-Chemisorption Pathways of H2 Molecule on Graphene Activated by a Hydrogenated Mono-Vacancy V11
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Isao Maruyama, Gagus Ketut Sunnardianto, and Koichi Kusakabe
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Materials science ,Graphene ,02 engineering and technology ,General Medicine ,021001 nanoscience & nanotechnology ,Photochemistry ,01 natural sciences ,Dissociation (chemistry) ,law.invention ,Chemisorption ,law ,Vacancy defect ,0103 physical sciences ,Molecule ,010306 general physics ,0210 nano-technology - Published
- 2016
8. Demethylation of methylmercury and the enhanced production of formaldehyde in mouse liver
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Takuya Uchikawa, Toshihiro Kanno, Yuji Ishii, Nobuko Mori, Akira Yasutake, Hideyuki Yamada, and Isao Maruyama
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Sarcosine ,Formaldehyde ,Administration, Oral ,010501 environmental sciences ,Kidney ,Toxicology ,030226 pharmacology & pharmacy ,01 natural sciences ,03 medical and health sciences ,chemistry.chemical_compound ,Methionine ,0302 clinical medicine ,Cytochrome P-450 Enzyme System ,Superoxides ,Animals ,Methylmercury ,Biotransformation ,0105 earth and related environmental sciences ,Demethylation ,biology ,Superoxide Dismutase ,Superoxide ,Cytochrome P450 ,Kidney metabolism ,Methylmercury Compounds ,Mice, Inbred C57BL ,Kinetics ,Liver ,chemistry ,Biochemistry ,Dealkylation ,biology.protein ,Female ,Dismutase - Abstract
Methylmercury (MeHg) is gradually changed to inorganic Hg after demethylation in animal tissues, and a selective quantification of inorganic Hg in the tissues is necessary to detect the reaction. We detected inorganic Hg formation in liver and kidney of mouse as early as 24 hr after MeHg injection. As an example of biological demethylation, the cytochrome P450 (P450)-mediated N-demethylation of drugs has been well documented, and formaldehyde was detected as a reaction product. Here we incubated mouse liver homogenate with added MeHg and observed a dose-dependent production of formaldehyde, as well as inorganic Hg formation. Since the amount of formaldehyde was approx. 500 times higher than that of the inorganic Hg that formed, the formaldehyde production would be stimulated by inorganic Hg formed from MeHg. We observed that inorganic Hg caused formaldehyde production, and it was enhanced by L-methionine and sarcosine. Thus, some biomolecules with S-methyl and N-methyl groups may function as methyl donors in the reaction. Using subcellular fractions of mouse liver, we observed that microsomal P450 did not participate in the demethylation of MeHg, but the greatest activity was located in the mitochondria-rich fraction. The addition of superoxide anion in the reaction mixture significantly enhanced the formaldehyde production, whereas Mn-superoxide dismutase depressed the reaction. Our present findings demonstrated that inorganic Hg formed by MeHg demethylation in mouse liver stimulated the endogenous formaldehyde production, and we observed that MeHg demethylation could be estimated by a formaldehyde analysis. Our results also suggested that superoxide anion is involved in the reaction.
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- 2016
9. Fractionally quantized Berry phases of magnetization plateaux in spin-$1/2$ Heisenberg multimer chains
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Shin Miyahara and Isao Maruyama
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Physics ,Condensed matter physics ,Strongly Correlated Electrons (cond-mat.str-el) ,General Physics and Astronomy ,FOS: Physical sciences ,01 natural sciences ,010305 fluids & plasmas ,Magnetization ,Condensed Matter - Strongly Correlated Electrons ,Geometric phase ,0103 physical sciences ,Condensed Matter::Strongly Correlated Electrons ,010306 general physics ,Spin (physics) - Abstract
We study the fractionally quantized $Z_N$ Berry phase, $\gamma_N=0, {2\pi \over N}, {4\pi \over N},\ldots, {2(N-1)\pi \over N}$, to characterize local $N$-mer spin structures at magnetization plateaux in spin-1/2 Heisenberg multimer ($N$-mer) models, i.e., highly frustrated $N$-leg ladder models, which are generalizations of an orthogonal dimer chain and have exact ground states in the strong multimer coupling region. We demonstrate that all $N$ types of Berry phases, which characterize magnetization-plateau phases, appear in a magnetic phase diagram when $N=2$ and $4$. We show that magnetization plateau with magnetization $\langle m\rangle$ and $D$-fold degenerated states has $\gamma_N=\pi (\langle m\rangle-1) D$, except for the Haldane phase with $\gamma_N=0$. In addition, we find that a complementary $Z_N$ Berry phase becomes non-zero in the $S=N/2$ Haldane phase for $N=2$ and 4. Because the exact quantization of the $Z_N$ Berry phases is protected by the translational (or rotational) symmetry along the rung direction, the $Z_N$ Berry phase has the potential to be applied for a wide class of magnetization plateaux in coupled multimer systems., Comment: 5 pages, 4 figures
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- 2018
- Full Text
- View/download PDF
10. Occurrence of Cobalamin Coenzymes in the Photosynthetic Green Alga, Chlorella vulgaris
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Katsuo Abe, Fumio Watanabe, Shigeo Takenaka, Yoshihisa Nakano, Isao Maruyama, and Yoshiyuki Tamura
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Chlorella vulgaris ,Biology ,Photosynthesis ,Applied Microbiology and Biotechnology ,Biochemistry ,Cobalamin ,Analytical Chemistry ,chemistry.chemical_compound ,Algae ,hemic and lymphatic diseases ,polycyclic compounds ,medicine ,heterocyclic compounds ,Molecular Biology ,integumentary system ,Organic Chemistry ,nutritional and metabolic diseases ,General Medicine ,Metabolism ,biology.organism_classification ,Chlorella ,chemistry ,Methylcobalamin ,Green algae ,Biotechnology ,medicine.drug - Abstract
To analyze cobalamin metabolism in photosynthetic green algae, the effects of cobalamin on growth of Chlorella vulgaris C-30 were studied and the algal cobalamin contents were assayed. Cobalamin significantly stimulated growth of the Chlorella cells, but biologically inactive cobalamin analogues did not. Chlorella grown in a cobalamin-free medium (control) contained cobalamin coenzymes, 5′-deoxyadenosylcobalamin (7.95 ± 0.31 ng/g wet weight) and methylcobalamin (2.72 ± 0.45 ng/g wet weight), of which the levels were increased significantly in cobalamin-supplemented cells. These results indicate that the alga has ability to take up exogenous cobalamin and synthesize the coenzyme forms.
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- 2017
11. Feeding effect of selenium enriched rotifers on larval growth and development in red sea bream Pagrus major
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Kazushi Takiyama, Hee Jin Kim, Yoshitaka Sakakura, Haruyuki Fujiki, Toshio Nakamura, Isao Maruyama, and Atsushi Hagiwara
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chemistry.chemical_classification ,Larva ,Larval growth ,biology ,Ecology ,Fish fin ,chemistry.chemical_element ,Rotifer ,Aquatic Science ,biology.organism_classification ,Accelerated Growth ,Red sea bream ,Pagrus major ,Selenium ,Animal science ,chemistry ,Composition (visual arts) ,Chlorella vulgaris ,Polyunsaturated fatty acid - Abstract
Feeding trials were conducted to investigate the effect of selenium (Se)-enriched rotifers on growth and development of red sea bream Pagrus major larvae. Fish were reared from fertilized eggs (98% hatch rate) to 20. days post hatch (dph) at 19. °C with two different food sources; non-enriched S-type rotifers (0.0. μg. Se/g D.W., control diet) or Se-enriched rotifers (2.2. μg. Se/g D.W., Se-enriched diet) at 10. rotifers/mL, respectively. On the last day of larviculture, the Se-enriched diet accelerated growth and developmental stage of fish larvae. The larvae fed Se-enriched rotifers were advanced in the following parameters compared to those fed control diet: total length (6.06 vs 5.53. mm), standard length (5.74 vs 5.26. mm), head length (1.46 vs 1.28. mm), eye diameter (0.57 vs 0.50. mm), the number of caudal fin rays (5.8 vs 1.9), and the proportion of individuals undergoing notochord flexion (55 vs 3%). Fish larvae of 20. dph showed higher Se concentration (9.5 ± 0.2. μg/g DW) with the Se-enriched diet than with the control diet (1.3 ± 0.3. μg/g DW), but there were no significant differences in the composition of polyunsaturated fatty acids which significantly affect larval growth and development. Therefore, the feeding of Se enriched rotifers enhanced growth and development of the red sea bream P. major larvae., Aquaculture, 432, pp.273-277; 2014
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- 2014
12. Comprehensive Support for a Child With Developmental Disabilities Who Was Reluctant to Go to School: Readjustment of Mother-Child Relations
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Hiroyuki Uno and Isao Maruyama
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- 2013
13. The influence of Parachlorella beyerinckii CK-5 on the absorption and excretion of methylmercury (MeHg) in mice
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Shoichiro Kumamoto, Yotaro Ando, Akira Yasutake, Yoshimitsu Kumamoto, Isao Maruyama, and Takuya Uchikawa
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medicine.medical_specialty ,Chlorella vulgaris ,Food Contamination ,Chlorella ,Urine ,Urinalysis ,Toxicology ,Excretion ,Feces ,Mice ,chemistry.chemical_compound ,Oral administration ,Internal medicine ,medicine ,Animals ,Methylmercury ,Gastrointestinal tract ,biology ,Mercury ,Methylmercury Compounds ,biology.organism_classification ,Mice, Inbred C57BL ,Endocrinology ,chemistry ,Environmental chemistry ,Dietary Supplements ,Drug Therapy, Combination ,Environmental Pollutants ,Female ,Powders - Abstract
Chlorella (Parachlorella beyerinckii CK-5), previously identified as Chlorella vulgaris CK-5, is a unicellular green algae that has for many years been used as a nutritional supplement. In order to investigate the effects of methylmercury (MeHg) detoxification by Chlorella, we examined the absorption and excretion of MeHg in mice. Female C57BL/6N mice were randomly divided into three groups of five, and were housed in metabolism cages. Mice were orally administered MeHg chloride at doses of 5 mg (4 mg Hg)/kg body weight with or without 100 mg/mouse of P. beyerinckii powder (BP), and were assigned to either a MeHg group or MeHg + BP group, accordingly. Twenty-four hr after oral administration, feces and urine were collected, and blood, liver, and kidney samples were obtained. Total mercury contents in the samples obtained were determined using an atomic absorption method. The amounts of Hg excreted in feces and urine of the MeHg + BP group were increased nearly 1.9 and 2.2-fold compared with those of the MeHg group. On the other hand, blood and organ Hg levels were not significantly different between two groups. These results suggest that the intake of BP may induce the excretion of Hg both in feces and urine, although it does not affect MeHg absorption from the gastrointestinal tract. The effect of BP on the tissue mercury accumulation may become evident in a long-term experiment.
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- 2010
14. Parachlorella beyerinckii accelerates lead excretion in mice
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Isao Maruyama, Yotaro Ando, Takashi Hasegawa, Takuya Uchikawa, Takeyuki Ueno, and Shoichiro Kumamoto
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Male ,medicine.medical_specialty ,Health, Toxicology and Mutagenesis ,Administration, Oral ,Chlorella ,Absorption (skin) ,Kidney ,Toxicology ,Excretion ,Feces ,Mice ,Pepsin ,Internal medicine ,medicine ,Animals ,Lead (electronics) ,Mice, Inbred ICR ,biology ,Chemistry ,Spectrophotometry, Atomic ,Public Health, Environmental and Occupational Health ,Kidney metabolism ,In vitro ,Endocrinology ,Lead ,Liver ,Lead acetate ,biology.protein ,Female ,Adsorption - Abstract
The effect of Parachlorella beyerinckii CK-5, previously identified as Chlorella vulgaris, on gastrointestinal absorption of lead was investigated in mice. Female ICR mice aged 7 weeks were orally administered lead acetate solution at doses of 20 mg and 40 mg of lead per mouse, with or without 100 mg of P. beyerinckii powder (BP). The mice were bred for 24 hours. The amount of lead excreted in feces within 24 hours, and the lead levels of the blood, liver and kidney were analyzed by atomic absorption spectrometry. The percentage of total fecal excretion in mice administered BP increased by 27.7% in 20 mg lead administered mice and 17.2% in 40 mg lead administered mice in comparison to control mice, respectively. On the other hand, the lead levels of the blood, liver and kidney of BPadministered mice at 24 hours after lead administration were 48-63% lower as compared with those of control mice. The lead adsorption ability of BP and the pepsin non-digestive residue of BP (dBP) were investigated in vitro. One hundred mg of BP and dBP could adsorb 10.6 mg and 6.0 mg of lead in a 20 mg per 10 mL of lead solution, respectively. The lead absorption abilities of BP and dBP were considered to contribute to the prevention of gastrointestinal absorption of lead and the promotion of the excretion of lead. These results suggested that BP treatment might be useful in animals and humans exposed to lead.
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- 2009
15. Early dynamics of hepatitis B virus in chimeric mice carrying human hepatocytes monoinfected or coinfected with genotype G
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Masaya Sugiyama, Yasuhito Tanaka, Hideaki Kato, Takashi Shimada, Satoru Takahashi, Isao Maruyama, Tomoyuki Shirai, Masataka Nagao, Tomoyuki Sakamoto, Yuzo Miyakawa, and Masashi Mizokami
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Hepatitis B virus ,Genotype ,Mice, SCID ,Transfection ,medicine.disease_cause ,Virus ,Cell Line ,Mice ,Orthohepadnavirus ,medicine ,Animals ,Humans ,Transplantation Chimera ,Severe combined immunodeficiency ,Hepatology ,biology ,Viral Core Proteins ,Sequence Analysis, DNA ,Hepatitis B ,biology.organism_classification ,medicine.disease ,Virology ,Liver ,Hepadnaviridae ,Superinfection ,DNA, Viral ,Hepatocytes ,Coinfection ,Viral disease ,Plasmids - Abstract
Of the 8 genotypes of HBV (genotypes A-H), genotype G is unique in that it has an insertion in the core gene and two stop codons in the precore region preventing the synthesis of hepatitis B e antigen. Most individuals with genotype G are coinfected with other genotypes, typically genotype A. Mice with severe combined immunodeficiency disease carrying human hepatocytes were infected with HBV particles propagated in Huh7 cells in culture. Mice monoinfected with genotype G did not raise detectable HBV DNA in serum, although products of the core gene emerged 4 to 8 weeks after inoculation. When they were superinfected with genotype A at week 10, however, HBV DNA of genotype A developed, which was replaced almost completely by that of genotype G within 10 weeks. Such a rapid takeover was also observed in mice initially infected with genotype A or C and superinfected with genotype G. Similar viral dynamics occurred in mice simultaneously coinfected with genotypes G and A. Takeover was markedly enhanced in mice inoculated with a serum passage containing genotype G with a trace of genotype A. Coinfection of mice with genotypes G and A induced abundant cellular steatosis along with increased fibrosis in the liver, which was not detected in mice monoinfected with genotype A or G. Conclusion: Genotype G can monoinfect chimeric mice at very low levels, and its replication increases maredly when coinfected with other genotypes. Coinfection with genotype G could enhance fibrosis under immunocompromised states. (HEPATOLOGY 2007;45:929–937.)
- Published
- 2007
16. Determination of Tomonaga-Luttinger parameters for a two-component liquid
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Shinsei Ryu, Isao Maruyama, Hitesh J. Changlani, and Olabode Mayodele Sule
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Physics ,Strongly Correlated Electrons (cond-mat.str-el) ,Matching (graph theory) ,Conformal field theory ,FOS: Physical sciences ,Function (mathematics) ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,Condensed Matter - Strongly Correlated Electrons ,Quantum mechanics ,Condensed Matter::Strongly Correlated Electrons ,Quantum information ,Central charge ,Scaling ,Lattice model (physics) ,Boson ,Mathematical physics - Abstract
We provide evidence for the mapping of critical spin-1 chains, in particular the SU(3) symmetric bilinear-biquadratic model with additional interactions, to free boson theories using exact diagonalization and the density matrix renormalization group algorithm. Using the correspondence with a conformal field theory with central charge c=2, we determine the analytic formulae for the scaling dimensions in terms of four Tomonaga-Luttinger liquid parameters. By matching the lowest scaling dimensions, we numerically calculate these field-theoretic parameters and track their evolution as a function of the parameters of the lattice model., 11 pages, 10 figures. The first two authors contributed equally to this work. Introduction updated, several referee comments incorporated
- Published
- 2015
17. Incorporation of Exogenous Docosahexaenoic Acid into Triacylglycerols and Polar Lipids of Chlorella vulgaris
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Tsugiyo Yukino, Hisashi Murata, Isao Maruyama, and Masahiro Hayashi
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chemistry.chemical_classification ,genetic structures ,biology ,General Chemical Engineering ,Chlorella vulgaris ,Dietary supplement ,food and beverages ,Fatty acid ,General Medicine ,General Chemistry ,Polar lipids ,biology.organism_classification ,Chlorella ,Food supplement ,Biochemistry ,chemistry ,Docosahexaenoic acid ,Time course ,lipids (amino acids, peptides, and proteins) - Abstract
Docosahexaenoic acid (DHA)-enriched Chlorella vulgaris is commonly used as a feed in fisheries and as a dietary supplement. The time course DHA uptake into the Chlorella cells and incorporation of DHA into the triacylglycerols (TAG) and polar lipids (PL) were examined. After the addition of DHA into the Chlorella culture, DHA was rapidly taken up by the Chlorella cells and was mainly incorporated into TAG. However, some DHA was also incorporated into PL molecules. Although the percentage of DHA in the total fatty acids of total cellular lipids reached at 67%, the percentage in the total fatty acids of PL was 27.5%. As for the effects of pH, exogenous DHA was mainly incorporated into TAG molecules at pH 5-7. At pH 3-4 and 8, the DHA accumulated as free fatty acid in the cells. The exogenous DHA was rapidly incorporated into TAG molecules within 24 hours at pH 5-8. The findings should contribute profitably to production of better fishery feed and food supplement by using DHA-enriched Chlorella.
- Published
- 2005
18. Time-dependent nuclear wavepacket dynamics of H+2by quasi-stationary Floquet approach
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Kaoru Yamanouchi, Isao Maruyama, and Tokuei Sako
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Floquet theory ,Physics ,Photon ,Wave packet ,Time evolution ,Condensed Matter Physics ,Laser ,Diatomic molecule ,Atomic and Molecular Physics, and Optics ,law.invention ,Wavelength ,law ,Atomic physics ,Light field - Abstract
The dissociation dynamics of H+2 in an intense ultrashort-pulsed laser light field (λ = 800 and 1200 nm, Γ = 100 fs, I = 1012–1014 W cm−2) is investigated by the quasi-stationary Floquet approach. The time-dependent dynamics of the dissociating wavepacket whose fate is governed mostly by the propagation through the one-photon and three-photon crossings are sensitively dependent on the characteristics of the light field such as the wavelength, temporal width and intensity. It is shown that the momentum distribution of the H+ fragment can be decomposed into the three Floquet channels having the dressed photon numbers (n = 0, 1, 2), leading to the secure assignment of the observed peak profiles of the momentum distribution of H+, and that the yield ratios of these three Floquet channels can be manipulated largely by preparing H+2 in a specific vibrational level prior to the interaction with the intense laser field.
- Published
- 2004
19. Activation of the CKI-CDK-Rb-E2F Pathway in Full Genome Hepatitis C Virus-expressing Cells
- Author
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Isao Maruyama, Shigenobu Tone, Yutaka Hoshikawa, Asao Katsume, Yohsuke Minatogawa, Kazuaki Inoue, Futoshi Shibasaki, Michael Reth, Hiroshi Ohmori, Michinori Kohara, Kazunari Taira, Kyoko Tsukiyama-Kohara, Hideko Nuriya, and Jun Ohkawa
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Time Factors ,Cell Cycle Proteins ,Cell Separation ,Hepacivirus ,medicine.disease_cause ,Retinoblastoma Protein ,Biochemistry ,Genome ,Genes, Reporter ,Cloning, Molecular ,Phosphorylation ,Promoter Regions, Genetic ,Oligonucleotide Array Sequence Analysis ,biology ,Cell Cycle ,Flow Cytometry ,Cyclin-Dependent Kinases ,Up-Regulation ,DNA-Binding Proteins ,Liver ,Hepatocellular carcinoma ,Casein Kinases ,Cell Division ,Plasmids ,Cyclin-Dependent Kinase Inhibitor p21 ,Gene Expression Regulation, Viral ,DNA, Complementary ,Hepatitis C virus ,Blotting, Western ,Immunoblotting ,Hyperphosphorylation ,Genome, Viral ,Transfection ,Cell Line ,Cyclin-dependent kinase ,Cyclins ,medicine ,Humans ,RNA, Messenger ,E2F ,Molecular Biology ,Models, Genetic ,RNA ,Cell Biology ,medicine.disease ,Virology ,Molecular biology ,digestive system diseases ,E2F Transcription Factors ,NS2-3 protease ,Hepatocytes ,biology.protein ,Protein Kinases ,Transcription Factors - Abstract
Hepatitis C virus (HCV) causes persistent infection in hepatocytes, and this infection is, in turn, strongly associated with the development of hepatocellular carcinoma. To clarify the mechanisms underlying these effects, we established a Cre/loxP conditional expression system for the precisely self-trimmed HCV genome in human liver cells. Passage of hepatocytes expressing replicable full-length HCV (HCR6-Rz) RNA caused up-regulation of anchorage-independent growth after 44 days. In contrast, hepatocytes expressing HCV structural, nonstructural, or all viral proteins showed no significant changes after passage for 44 days. Only cells expressing HCR6-Rz passaged for 44 days displayed acceleration of CDK activity, hyperphosphorylation of Rb, and E2F activation. These results demonstrate that full genome HCV expression up-regulates the CDK-Rb-E2F pathway much more effectively than HCV proteins during passage.
- Published
- 2004
20. Conductance through Quantum Dots Studied by Finite Temperature DMRG
- Author
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Isao Maruyama, Kazuo Ueda, and Naokazu Shibata
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Physics ,Local density of states ,Condensed Matter - Mesoscale and Nanoscale Physics ,Condensed matter physics ,Unitarity ,Density matrix renormalization group ,Analytic continuation ,FOS: Physical sciences ,General Physics and Astronomy ,Conductance ,Charge (physics) ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Quantum dot ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,Density of states ,Condensed Matter::Strongly Correlated Electrons - Abstract
With the Finite temperature Density Matrix Renormalization Group method (FT-DMRG), we depeloped a method to calculate thermo-dynamical quantities and the conductance of a quantum dot system. Conductance is written by the local density of states on the dot. The density of states is calculated with the numerical analytic continuation from the thermal Green's function which is obtained directly from the FT-DMRG. Typical Kondo behaviors in the quantum dot system are observed conveniently by comparing the conductance with the magnetic and charge susceptibilities: Coulomb oscillation peaks and the unitarity limit. We discuss advantage of this method compared with others., Comment: 14 pages, 13 fiures
- Published
- 2004
21. Preparation of Protoplasts from Chlorella vulgaris K-73122 and Cell Wall Regeneration of Protoplasts from C. vulgaris K-73122 and C-27
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Takahisa Miyamoto, Koushirou Suga, Isao Maruyama, Masayoshi Iio, Ken-ichi Honjoh, Fuminori Shinohara, and Shoji Hatano
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Cell wall ,Regeneration (biology) ,Chlorella vulgaris ,Botany ,Protoplast ,Biology ,Agronomy and Crop Science ,Biotechnology - Published
- 2003
22. Two Low-temperature-inducibleChlorellaGenes forΔ12 andω-3 Fatty Acid Desaturase (FAD): Isolation ofΔ12 and ω-3 fad cDNA Clones,…
- Author
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Ken-ichi Honjoh, Masayoshi Iio, Isao Maruyama, Takahisa Miyamoto, Shoji Hatano, Naoki Furuya, Koushirou Suga, Fuminori Shinohara, Hideyuki Shimizu, Yoshie Hirabaru, and Koutarou Nishi
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chemistry.chemical_classification ,Linolenic acid ,Linoleic acid ,Organic Chemistry ,Fatty acid ,General Medicine ,Biology ,Applied Microbiology and Biotechnology ,Biochemistry ,Analytical Chemistry ,Amino acid ,Oleic acid ,chemistry.chemical_compound ,Fatty acid desaturase ,chemistry ,Complementary DNA ,biology.protein ,Molecular Biology ,Peptide sequence ,Biotechnology - Abstract
In an attempt to clarify the involvement of fatty acid desaturases (FADs) in the freezing tolerance of Chlorella vulgaris IAM C-27, developed by hardening, we have isolated cDNA clones for two types of FADs from the Chlorella strain, based on the sequence information of genes for Δ12 and ω-3 FADs, respectively desaturating oleic acid (18:1) to linoleic acid (18:2) and linoleic acid (18:2) to linolenic acid (18:3). The deduced amino acid sequence of the first clone, designated CvFad2, showed about 66% similarity to the microsomal Δ12 FADs from several higher plants and this gene had Δ12 FAD activity when expressed in Saccharomyces cerevisiae. The predicted protein encoded by a second gene, designated CvFad3, showed about 60% similarity to the microsomal and plastidial ω-3 FADs from several higher plants. The features of the amino acid sequences of the C- and N-terminal regions of CvFAD3 and fatty acid analysis of polar lipids in transgenic tobacco plant expressing the CvFad3 gene suggested that this gene e...
- Published
- 2002
23. Preventive effects of Chlorella on skeletal muscle atrophy in muscle-specific mitochondrial aldehyde dehydrogenase 2 activity-deficient mice
- Author
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Isao Maruyama, Shigeo Ohta, Yoshihiko Suzuki, Yuya Nakashima, Ikuroh Ohsawa, Shoichiro Kumamoto, and Kiyomi Nishimaki
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Male ,Genetically modified mouse ,medicine.medical_specialty ,Aldehyde dehydrogenase ,Mice, Transgenic ,Chlorella ,medicine.disease_cause ,Mice ,Internal medicine ,medicine ,Animals ,Humans ,Muscle, Skeletal ,ALDH2 ,Oxidase test ,biology ,Aldehyde Dehydrogenase, Mitochondrial ,Mitochondrial cytochrome c oxidase ,General Medicine ,Aldehyde Dehydrogenase ,medicine.disease ,Muscle atrophy ,Mitochondria ,Mice, Inbred C57BL ,Disease Models, Animal ,Muscular Atrophy ,Oxidative Stress ,Endocrinology ,Complementary and alternative medicine ,Biochemistry ,Aldehyde dehydrogenase 2 ,Sarcopenia ,biology.protein ,Female ,Creatine kinase ,medicine.symptom ,Oxidative stress ,Research Article - Abstract
Background Oxidative stress is involved in age-related muscle atrophy, such as sarcopenia. Since Chlorella, a unicellular green alga, contains various antioxidant substances, we used a mouse model of enhanced oxidative stress to investigate whether Chlorella could prevent muscle atrophy. Methods Aldehyde dehydrogenase 2 (ALDH2) is an anti-oxidative enzyme that detoxifies reactive aldehydes derived from lipid peroxides such as 4-hydroxy-2-nonenal (4-HNE). We therefore used transgenic mice expressing a dominant-negative form of ALDH2 (ALDH2*2 Tg mice) to selectively decrease ALDH2 activity in the muscles. To evaluate the effect of Chlorella, the mice were fed a Chlorella-supplemented diet (CSD) for 6 months. Results ALDH2*2 Tg mice exhibited small body size, muscle atrophy, decreased fat content, osteopenia, and kyphosis, accompanied by increased muscular 4-HNE levels. The CSD helped in recovery of body weight, enhanced oxidative stress, and increased levels of a muscle impairment marker, creatine phosphokinase (CPK) induced by ALDH2*2. Furthermore, histological and histochemical analyses revealed that the consumption of the CSD improved skeletal muscle atrophy and the activity of the mitochondrial cytochrome c oxidase. Conclusions This study suggests that long-term consumption of Chlorella has the potential to prevent age-related muscle atrophy.
- Published
- 2014
24. Fermi Surface Shape Controlling by Element Substitution in Tl-Based Cuprates
- Author
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Isao Maruyama, Satoaki Miyao, Kazuhiko Kuroki, Koichi Kusakabe, and Hirofumi Sakakibara
- Subjects
Physics ,Condensed matter physics ,Substitution (logic) ,Fermi surface ,Cuprate ,Element (category theory) - Published
- 2014
25. Effect of maternal Chlorella supplementation on carotenoid concentration in breast milk at early lactation
- Author
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Takuya Uchikawa, Kiyoshi Noda, Junya Nagayama, Hiroshi Shimomura, Michiyoshi Miyahara, and Isao Maruyama
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Vitamin ,Adult ,Lutein ,Physiology ,Chlorella ,Breast milk ,chemistry.chemical_compound ,Pregnancy ,Zeaxanthins ,Lactation ,Medicine ,Humans ,Vitamin A ,Carotenoid ,chemistry.chemical_classification ,biology ,Milk, Human ,business.industry ,food and beverages ,Maternal Nutritional Physiological Phenomena ,biology.organism_classification ,medicine.disease ,beta Carotene ,Carotenoids ,Diet ,Zeaxanthin ,medicine.anatomical_structure ,Biochemistry ,chemistry ,Dietary Supplements ,Female ,business ,Food Science - Abstract
Breast milk carotenoids provide neonates with a source of vitamin A and potentially, oxidative stress protection and other health benefits. Chlorella, which has high levels of carotenoids such as lutein, zeaxanthin and β-carotene, is an effective dietary source of carotenoids for humans. In this study, the effect of maternal supplementation with Chlorella on carotenoid levels in breast milk at early lactation was investigated. Ten healthy, pregnant women received 6 g of Chlorella daily from gestational week 16–20 until the day of delivery (Chlorella group); ten others did not (control group). Among the carotenoids detected in breast milk, lutein, zeaxanthin and β-carotene concentrations in the Chlorella group were 2.6-fold (p = 0.001), 2.7-fold (p = 0.001) and 1.7-fold (p = 0.049) higher, respectively, than those in the control group. Our study shows that Chlorella intake during pregnancy is effective in improving the carotenoid status of breast milk at early lactation.
- Published
- 2014
26. The Influence of Chlorella and Its Hot Water Extract Supplementation on Quality of Life in Patients with Breast Cancer
- Author
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Naoto Noguchi, Akira Yamada, and Isao Maruyama
- Subjects
Gerontology ,Vitamin ,medicine.medical_specialty ,Test food ,biology ,Article Subject ,business.industry ,Significant group ,lcsh:Other systems of medicine ,biology.organism_classification ,medicine.disease ,lcsh:RZ201-999 ,Clinical trial ,Chlorella ,chemistry.chemical_compound ,Breast cancer ,Complementary and alternative medicine ,chemistry ,Internal medicine ,Dry skin ,medicine ,In patient ,medicine.symptom ,business ,Research Article - Abstract
A self-control, randomized, and open-label clinical trial was performed to test the effects of the unicellular green algaeChlorellaand hot water extract supplementation on quality of life (QOL) in patients with breast cancer. Forty-five female patients with breast cancer who were living at home and not hospitalized were randomly assigned to 3 groups receiving vitamin mix tablet (control),Chlorellagranules (test food-1), orChlorellaextract drink (test food-2) daily for one month. The Functional Assessment of Cancer Therapy-Breast (FACT-B), the Izumo scale for abdominal symptom-specific QOL, and a narrative-form questionnaire were used to determine outcomes. Data of thirty-six subjects were included for final analysis. FACT-B scores at presupplementation found no significant group differences in all subscales. Scores on the breast cancer subscale in theChlorellagranule group significantly increased during the supplementation period (P=0.042). Fifty percent of theChlorellaextract group reported positive effects by the test food such as reduction of fatigue and improvements of dry skin (P<0.01versus control group). The findings suggested the beneficial effects ofChlorellaon breast cancer-related QOL and ofChlorellaextract on vitality status in breast cancer patients. These findings need to be confirmed in a larger study.
- Published
- 2014
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27. Collateral occurrence of deimination of keratins with differentiation of an immortalized newborn rat keratinocyte cell line cultured at air–liquid interface
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Tatsuo Senshu, Takako Ohsawa, and Isao Maruyama
- Subjects
Keratinocytes ,Time Factors ,Hydrolases ,Cellular differentiation ,Blotting, Western ,Cell Culture Techniques ,Dermatology ,Biology ,Biochemistry ,Cell Line ,Type II keratin ,Tissue culture ,Protein-Arginine Deiminase Type 4 ,Keratin ,Stratum corneum ,medicine ,Animals ,Molecular Biology ,chemistry.chemical_classification ,integumentary system ,Cell Differentiation ,Immunohistochemistry ,Rats ,Cell biology ,medicine.anatomical_structure ,Animals, Newborn ,chemistry ,Cell culture ,Protein-Arginine Deiminases ,Keratins ,Electrophoresis, Polyacrylamide Gel ,Epidermis ,Keratinocyte - Abstract
We devised a simple method to maintain an immortalized newbown rat keratinocyte cell line at the air–liquid interface using a tissue culture insert fitted with a microporous membrane. The cells formed stratified layers of flattened and anucleated cells resembling stratum corneum of the epidermis. Deiminated proteins, which are localized in the cornified layer of epidermis as the reaction products of peptidylarginine deiminase were detected immunohistochemically in the differentiated cells. Western blot analyses revealed that major deiminated proteins were type I keratins K10 and K14. Deiminated products of type II keratin K5 were found as minor components. Our observations show that deimination of keratins might be correlated with terminal differentiation of the immortalized keratinocyte cell line.
- Published
- 1999
28. Beneficial effects of Chlorella on glucose and lipid metabolism in obese rodents on a high-fat diet
- Author
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Naoto Noguchi, Fumiko Konishi, Teruyoshi Yanagita, Isao Maruyama, Yotaro Ando, and Shoichiro Kumamoto
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Blood Glucose ,Male ,medicine.medical_specialty ,Endocrinology, Diabetes and Metabolism ,Adipose tissue ,Mice, Obese ,Chlorella ,Intra-Abdominal Fat ,Diet, High-Fat ,Rats, Sprague-Dawley ,chemistry.chemical_compound ,Mice ,Insulin resistance ,Adipokines ,Internal medicine ,Hyperinsulinism ,Hyperlipidemia ,medicine ,Adipocytes ,Animals ,Insulin ,Obesity ,Triglycerides ,Nutrition and Dietetics ,Triglyceride ,Adiponectin ,business.industry ,Leptin ,Lipid metabolism ,Hypertrophy ,medicine.disease ,Lipid Metabolism ,Dietary Fats ,Rats ,Mice, Inbred C57BL ,Endocrinology ,chemistry ,Plant Preparations ,Metabolic syndrome ,Insulin Resistance ,business ,Phytotherapy - Abstract
Summary Background Obesity-induced glucose and lipid metabolism disorders have become risk factors for lifestyle diseases. Powderized Parachlorella beijerinckii (BP) and its hot water extract (BCEx) are believed to be useful for preventing common diseases such as hypertension, arteriosclerosis, and hyperlipidemia. The present study investigated how chlorella components influence common diseases in obese mice and rats on a high-fat diet. Methods We fed C57BL/6J mice a high-fat diet containing 5% BP, and then weighed their organs, tested their glucose tolerance and insulin sensitivity, and analyzed their serum. Further, we fed Sprague-Dawley rats with a high-fat diet containing 1% BCEx, and then weighed their organs and analyzed their serum parameters. Results BP administration had no effect on high-fat diet-induced obesity. However, compared with high-fat diet group, BP group had improved glucose tolerance and insulin sensitivity and inhibited the hypertrophic growth of visceral fat cells. In addition, BP group had improved serum adiponectin, leptin and monocyte chemoattractant protein-1 (MCP-1) levels. The MCP-1 expression level at epididymal fat was decreased at BP group. BCEx administration reduced amount of peritesticular fat and serum triglyceride (TG) levels. Conclusions The results suggest that the antihyperinsulinemic effects of BP are due to the modulation of adipose tissue hypertrophy and adipocytokine secretion. BCEx inhibited the accumulation of visceral fat and serum TG. The study showed that BP and BCEx improve glucose and lipid metabolism disorders caused by a high-fat diet.
- Published
- 2012
29. Incommensurate matrix product state for quantum spin systems
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Hiroshi Ueda and Isao Maruyama
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Physics ,Strongly Correlated Electrons (cond-mat.str-el) ,Condensed matter physics ,Spontaneous symmetry breaking ,Computer Science::Neural and Evolutionary Computation ,FOS: Physical sciences ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,Condensed Matter - Strongly Correlated Electrons ,Variational method ,Operator (computer programming) ,Zigzag ,Quantum mechanics ,Thermodynamic limit ,Condensed Matter::Strongly Correlated Electrons ,Matrix product state - Abstract
We introduce a matrix product state (MPS) with an incommensurate periodicity by applying the spin-rotation operator of each site to a uniform MPS in the thermodynamic limit. The spin rotations decrease the variational energy with accompanying translational symmetry breaking and the rotational symmetry breaking in the spin space even if the Hamiltonian has the both symmetries. The optimized pitch of rotational operator reflects the commensurate/incommensurate properties of spin-spin correlation functions in the $S=1/2$ Heisenberg chain and the $S=1/2$ ferro-antiferro zigzag chain., 6 pages, 5 figures
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- 2012
30. MATRIX PRODUCT STATES IN QUANTUM INTEGRABLE MODELS
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Hosho Katsura and Isao Maruyama
- Subjects
Physics ,Separable state ,Integrable system ,Quantum mechanics ,Density matrix renormalization group ,Quantum inverse scattering method ,Quantum ,Matrix multiplication - Published
- 2012
31. Quantum Entanglement of Tensor Networks with Symmetry Projections
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Masashi Orii, Hiroshi Ueda, and Isao Maruyama
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Physics ,Quantum Physics ,Strongly Correlated Electrons (cond-mat.str-el) ,Entropy (statistical thermodynamics) ,Lattice (group) ,General Physics and Astronomy ,FOS: Physical sciences ,Quantum entanglement ,Space (mathematics) ,Condensed Matter - Strongly Correlated Electrons ,Variational method ,Homogeneous space ,Tensor ,Quantum Physics (quant-ph) ,Matrix product state ,Mathematical physics - Abstract
We investigate the global-symmetry projections applied to the tensor network states from the view point of the entanglement entropy and the mutual information. The projections to the translational invariant space and to the total-$S^z$-zero space give logarithmically increasing mutual information with respect to the system size. In the anti-ferromagnetic $S=1/2$ Heisenberg chain and lattice, the optimized energies become accurate numerically by using variational states of the projected tensor network states, because the projections reflecting symmetries of the ground states generate quantum entanglement., Comment: 12 pages, 3 figures, to be published in J. Phys. Soc. Jpn
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- 2012
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32. Chlorella suppresses methylmercury transfer to the fetus in pregnant mice
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Takuya Uchikawa, Yotaro Ando, Shoichiro Kumamoto, Akira Yasutake, and Isao Maruyama
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Male ,Physiology ,Chlorella ,Toxicology ,Mercury poisoning ,chemistry.chemical_compound ,Basal (phylogenetics) ,Mice ,Pregnancy ,medicine ,Animals ,Tissue Distribution ,Methylmercury ,Maternal-Fetal Exchange ,Fetus ,Maternal-fetal exchange ,biology ,Methylmercury Compounds ,biology.organism_classification ,medicine.disease ,Mice, Inbred C57BL ,chemistry ,Distilled water ,Animals, Newborn ,Organ Specificity ,Immunology ,Dietary Supplements ,Mercury Poisoning ,Female ,Powders ,Water Pollutants, Chemical - Abstract
To investigate the effects of chlorella on methylmercury (MeHg) transfer to the fetus during pregnancy, female C57BL/6N mice (aged 10 weeks) were housed for 7 to 8 weeks, from 4 weeks before mating to birth, with diets containing 0% or 10% chlorella powder (CP) and MeHg-containing drinking water (2 µg Hg/ml). The consumption volume of the MeHg-containing water was limited to 15 ml/mouse/week throughout the experiment. Distilled water and a basal diet (0% CP) was given to control mice. Except for the mating period, during the 5(th) week, mice were housed individually until parturition. Two neonates were randomly selected from each mother mouse within 24 hr after parturition for Hg analysis of the blood, brain, liver, and kidneys. Mother mice were sacrificed on the same day as neonates to obtain tissue samples for Hg analysis. The blood and brain Hg levels of both neonates and mothers in the CP diet group were significantly lower than those in the basal diet group. Although the hepatic and renal Hg levels were not significant in mothers between the two dietary groups, in neonates, the CP diet group showed significantly lower Hg levels in these tissues than the basal diet group. The results obtained here revealed that continuous CP intake suppressed MeHg transfer to the fetus, in addition to effective suppressing MeHg accumulation in brains of the mothers.
- Published
- 2011
33. Sine-square deformation of free fermion systems in one and higher dimensions
- Author
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Isao Maruyama, Toshiya Hikihara, and Hosho Katsura
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Periodic system ,Physics ,Quantum Physics ,Statistical Mechanics (cond-mat.stat-mech) ,FOS: Physical sciences ,Fermion ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,Computer Science::Performance ,symbols.namesake ,Quantum Gases (cond-mat.quant-gas) ,Quantum mechanics ,symbols ,Sine ,Ground state ,Hamiltonian (quantum mechanics) ,Wave function ,Quantum Physics (quant-ph) ,Condensed Matter - Quantum Gases ,Scaling ,Computer Science::Databases ,Condensed Matter - Statistical Mechanics ,Fermi Gamma-ray Space Telescope ,Computer Science::Information Theory - Abstract
We study free fermion systems with the sine-square deformation (SSD), in which the energy scale of local Hamiltonians is modified according to the scaling function f(x)=sin^2[\pi(x-1/2)/L], where x is the position of the local Hamiltonian and L is the length of the system in the x direction. It has been revealed that when applied to one-dimensional critical systems the SSD realizes the translationally-invariant ground state which is the same as that of the uniform periodic system. In this paper, we propose a simple theory to explain how the SSD maintains the translational invariance in the ground-state wave function. In particular, for a certain one-dimensional system with SSD, it is shown that the ground state is exactly identical with the Fermi sea of the uniform periodic chain. We also apply the SSD to two-dimensional systems and show that the SSD is able to suppress the boundary modulations from the open edges extremely well, demonstrating that the SSD works in any dimensions and in any directions., Comment: 9 pages, 6 figures. v2: accepted version
- Published
- 2011
34. Enhanced elimination of tissue methylmercury in Parachlorella beijerinckii-fed mice
- Author
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Yotaro Ando, Yoshimitsu Kumamoto, Shoichiro Kumamoto, Takuya Uchikawa, Isao Maruyama, and Akira Yasutake
- Subjects
medicine.medical_specialty ,Time Factors ,Administration, Oral ,Urine ,Chlorella ,Toxicology ,Kidney ,Excretion ,chemistry.chemical_compound ,Feces ,Mice ,Internal medicine ,medicine ,Animals ,Tissue Distribution ,Methylmercury ,Kidney metabolism ,Brain ,Glutathione ,Metabolism ,Methylmercury Compounds ,Mice, Inbred C57BL ,Endocrinology ,medicine.anatomical_structure ,Biochemistry ,chemistry ,Inactivation, Metabolic ,Female ,Plant Preparations - Abstract
To investigate the influence of Chlorella (Parachlorella beijerinckii) on the excretion and tissue accumulation of methylmercury (MeHg), we orally administered 5 mg/kg of MeHg chloride (4 mg Hg/kg) to female C57BL/6N mice (aged 10 weeks). The mice were housed in metabolism cages to collect urine and feces for 3 weeks with diets containing 0%, 5%, or 10% P. beijerinckii powder (BP) in a basal diet (CE-2). The lowered blood Hg levels in the 5% and 10% BP groups became significant compared to those of the control group (0% BP) as early as day 7. During the 21 days of testing, significant increases in the cumulative Hg eliminations into urine (5% BP) and feces (5% and 10% BP) were found in the BP groups. Twenty-one days after administration, the organ Hg levels in both BP groups tended to decrease compared to that of the control group. The reduction of Hg levels in the kidney and brain were significant, whereas that in the liver was not. Although tissue Hg levels are known to be closely related to glutathione (GSH) metabolism, no difference was found in GSH levels in the blood or organs between the control group and the 10% BP group. These results suggest that continuous BP intake accelerates the excretion of MeHg and subsequently decreases tissue Hg levels in mice, with no alteration of GSH metabolism. We should conduct further research to elucidate details regarding the mechanism of BP-induced enhancement of MeHg excretion.
- Published
- 2011
35. Application of Uniform Matrix Product State to Quantum Phase Transition with a Periodicity Change
- Author
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Isao Maruyama and Hiroshi Ueda
- Subjects
Quantum phase transition ,Physics ,Condensed Matter::Quantum Gases ,Phase transition ,Condensed matter physics ,Strongly Correlated Electrons (cond-mat.str-el) ,Heisenberg model ,General Physics and Astronomy ,FOS: Physical sciences ,Magnetization ,Correlation function (statistical mechanics) ,Condensed Matter - Strongly Correlated Electrons ,Variational method ,Quantum mechanics ,Condensed Matter::Superconductivity ,Condensed Matter::Strongly Correlated Electrons ,Critical exponent ,Matrix product state - Abstract
As a method beyond the mean-field analysis, a matrix product state (MPS) with incommensurate periodicity is applied to detect phase transitions accompanied with periodicity change, where the incommensurate MPS is generated by acting local-spin-rotation operators with the incommensurate periodicity on a uniform MPS. As a commensurate/commensurate change, we calculate the partial ferro -- perfect ferro phase transition in the $S=1/2$ Heisenberg model and its critical exponent of the magnetization curve. As a commensurate/incommensurate change, we calculate the S=1 Heisenberg model with bilinear and biquadratic interactions which has periodicity change in the spin-spin correlation function., Comment: 4 pages, 3 figures, Supplement (Proc. TOKIMEKI2011) Program No.25-P-36
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- 2011
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36. The Culture of the Rotifer Brachionus plicatilis with Chlorella vulgaris Containing Vitamin B12in its Cells
- Author
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Kazutsugu Hirayama and Isao Maruyama
- Subjects
biology ,Mass culture ,Chlorella vulgaris ,Rotifer ,Aquatic Science ,Brachionus ,biology.organism_classification ,Yeast ,Chlorella ,Botany ,Dry matter ,Food science ,Vitamin B12 ,Agronomy and Crop Science - Abstract
The rotifer Brachionus plicatilis requires vitamin B12. Freshwater Chlorella, which is produced by traditional culture, cannot support rotifer growth under bacteria-free conditions. However, Chlorella enriched with vitamin B12 can support rotifer growth. To attain stable mass production of Brachionus, it is desirable to develop a food that can completely support growth of the rotifers. The authors cultured rotifers at experimental and mass culture scale with concentrated Chlorella vulgaris suspension enriched with vitamin B12 in their cells. Chlorella suspensions were prepared containing different amounts of vitamin B12 in their cells, and rotifers were then cultured in 20 ml of the prepared suspensions. The highest rotifer yield was obtained from the group cultured with Chlorella containing more vitamin B12 in their cells. The suitable content of vitamin B12 in the concentrated Chlorella suspension commercially available for mass culture of the rotifer is considered to be 200 μg per 100 g dry matter of Chlorella. The amount of vitamin B12 necessary to produce one individual rotifer is calculated at 0.32 pg. The authors conducted mass production of the rotifer with baker's yeast and refrigerated concentrated Chlorella containing vitamin B12 Rotifer culture with vitamin B12 was more stable and showed 1.3 times higher production than with normal Chlorella.
- Published
- 1993
37. Topological quantum phase transition in the BEC-BCS crossover
- Author
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Yasuhiro Hatsugai, Mitsuhiro Arikawa, and Isao Maruyama
- Subjects
Condensed Matter::Quantum Gases ,Quantum phase transition ,Superconductivity ,Physics ,Condensed matter physics ,Condensed Matter::Other ,Condensation ,Crossover ,Fermion ,Quantum phases ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,Geometric phase ,Condensed Matter::Superconductivity ,Quantum mechanics ,Berry connection and curvature - Abstract
A crossover between the Bose-Einstein condensation (BEC) and BCS superconducting state is described topologically in the chiral symmetric fermion system with attractive interaction. Using a local ${Z}_{2}$ Berry phase, we found a quantum phase transition between the BEC and BCS phases without accompanying the bulk gap closing.
- Published
- 2010
38. Theorems on ground-state phase transitions in Kohn-Sham models given by the Coulomb density functional
- Author
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Koichi Kusakabe and Isao Maruyama
- Subjects
Statistics and Probability ,Physics ,Coupling constant ,Condensed Matter - Materials Science ,Phase transition ,Statistical Mechanics (cond-mat.stat-mech) ,General Physics and Astronomy ,Kohn–Sham equations ,Charge density ,Materials Science (cond-mat.mtrl-sci) ,FOS: Physical sciences ,Statistical and Nonlinear Physics ,Modeling and Simulation ,Quantum mechanics ,Coulomb ,Density of states ,Density functional theory ,Ground state ,Condensed Matter - Statistical Mechanics ,Mathematical Physics - Abstract
Some theorems on derivatives of the Coulomb density functional with respect to the coupling constant $\lambda$ are given. Consider an electron density $n_{GS}({\bf r})$ given by a ground state. A model Fermion system with the reduced coupling constant, $\lambda, Comment: 19 pages
- Published
- 2010
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39. Edge states of a spin-12two-leg ladder with four-spin ring exchange
- Author
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Yasuhiro Hatsugai, Isao Maruyama, Mitsuhiro Arikawa, and Shou Tanaya
- Subjects
Physics ,Maple ,Condensed matter physics ,Topological insulator ,engineering ,Condensed Matter::Strongly Correlated Electrons ,Quantum entanglement ,Edge states ,Quantum spin liquid ,engineering.material ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials - Abstract
A topological insulator and its spin analog as a gapped spin liquid have characteristic low-energy excitations (edge states) within the gap when the systems have boundaries. This is the bulk-edge correspondence, which implies that the edge states themselves characterize the gapped bulk spin liquid. Based on the general principle, we analyzed the vector chirality and rung-singlet phases of the spin-$\frac{1}{2}$ ladder with ring exchange by using the edge states and the entanglement entropy.
- Published
- 2009
40. Topological identification of a spin-12two-leg ladder with four-spin ring exchange
- Author
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Isao Maruyama, Yasuhiro Hatsugai, and Takaaki Hirano
- Subjects
Physics ,Quantum phase transition ,Ring (mathematics) ,High Energy Physics::Phenomenology ,Phase (waves) ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,Geometric phase ,Quantum mechanics ,Condensed Matter::Strongly Correlated Electrons ,Singlet state ,Berry connection and curvature ,Invariant (mathematics) ,Spin-½ - Abstract
A spin-$\frac{1}{2}$ two-leg ladder with four-spin ring exchange is studied by quantized Berry phases, used as local-order parameters. Reflecting local objects, nontrivial $(\ensuremath{\pi})$ Berry phase is founded on a rung for the rung-singlet phase and on a plaquette for the vector-chiral phase. Since the quantized Berry phase is topologically invariant for gapped systems with the time-reversal symmetry, topologically identical models can be obtained by the adiabatic modification. The rung-singlet phase is adiabatically connected to a decoupled rung-singlet model and the vector-chiral phase is connected to a decoupled vector-chiral model. Decoupled models reveal that the local objects are a local singlet and a plaquette singlet, respectively.
- Published
- 2009
41. Ferromagnetism in the Hubbard model with Topological/Non-Topological Flat Bands
- Author
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Hosho Katsura, Isao Maruyama, Hal Tasaki, and Akinori Tanaka
- Subjects
Coupling ,Physics ,Chern class ,Condensed matter physics ,Hubbard model ,Strongly Correlated Electrons (cond-mat.str-el) ,Statistical Mechanics (cond-mat.stat-mech) ,Zero (complex analysis) ,General Physics and Astronomy ,FOS: Physical sciences ,Magnetic flux ,Coulomb repulsion ,Condensed Matter - Strongly Correlated Electrons ,Ferromagnetism ,Condensed Matter::Strongly Correlated Electrons ,Condensed Matter - Statistical Mechanics - Abstract
We introduce and study two classes of Hubbard models with magnetic flux or with spin-orbit coupling, which have a flat lowest band separated from other bands by a nonzero gap. We study the Chern number of the flat bands, and find that it is zero for the first class but can be nontrivial in the second. We also prove that the introduction of on-site Coulomb repulsion leads to ferromagnetism in both the classes., Comment: 6 pages, 5 figures
- Published
- 2009
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42. Molecular epidemiology and interferon susceptibility of the natural recombinant hepatitis C virus strain RF1_2k/1b
- Author
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Florence Legrand-Abravanel, Yasuhito Tanaka, Isabelle Moreau, Jaques Izopet, Fuat Kurbanov, Aziza Azlarova, Takashi Shimada, Stefania Bonetto, Masashi Mizokami, Isao Maruyama, Tomoyoshi Ohno, Hiroshi Kamitsukasa, E. V. Chub, Sergei Netesov, Liam J. Fanning, and Nikolai V. Naoumov
- Subjects
Adult ,Male ,Genotype ,Hepatitis C virus ,Population ,Molecular Sequence Data ,Hepacivirus ,Biology ,Interferon alpha-2 ,Recombinant virus ,medicine.disease_cause ,Antiviral Agents ,Virus ,Polyethylene Glycols ,Evolution, Molecular ,chemistry.chemical_compound ,Mice ,Young Adult ,Interferon ,Ribavirin ,medicine ,Immunology and Allergy ,Animals ,Humans ,education ,NS5B ,Recombination, Genetic ,education.field_of_study ,Molecular Epidemiology ,Interferon-alpha ,Middle Aged ,Virology ,Hepatitis C ,Recombinant Proteins ,Infectious Diseases ,chemistry ,Female ,Viral load ,medicine.drug - Abstract
BACKGROUND Hepatitis C virus (HCV) genotype is an important determinant of virological response to antiviral therapies. Currently, there are no data available on the molecular epidemiology and interferon susceptibility of the natural intergenotypic recombinant RF1_2k/1b (RF1) strain. METHODS Genotyping and RF1-PCR screening were performed on samples from 604 HCV RNA-positive individuals from 7 countries. uPA/SCID mice carrying human hepatocytes (chimeric mice) were infected with the RF1_2k/1b strain, and the susceptibility of the strain to interferon and ribavirin was compared with the susceptibilities of 2 different strains of genotype B, used as references. RESULTS Six new RF1 cases were identified in this study; 5 (2%) of 281 in Russia and 1 (1%) of 90 in Uzbekistan. Phylogenetic analyses based on Core/E1 and NS5b indicated that all RF1 representatives share a common evolutionary ancestor. Infection with RF1 was established in chimeric mice. Reduction of RF1 viral load was observed in response to 3 injections of 3 microg/kg pegylated-interferon alpha-2a alone or in combination with 50 mg/kg of ribavirin (0.5 or 1.4 log-copies/mL). CONCLUSIONS All identified RF1-type strains appear to be introduced from a single source, suggesting that intergenotypic recombination in HCV is sporadic and not associated with cocirculation of different genotypes in a population. The RF1 strain in this study was responsive to interferon in vivo.
- Published
- 2008
43. Non-adiabatic effect on Laughlin's argument of the quantum Hall effect
- Author
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Isao Maruyama and Yasuhiro Hatsugai
- Subjects
Physics ,History ,Condensed Matter - Mesoscale and Nanoscale Physics ,Intermediate region ,Physics::Optics ,FOS: Physical sciences ,Impurity effect ,Quantum Hall effect ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Computer Science Applications ,Education ,Quantum mechanics ,Electric field ,Lattice (order) ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,Adiabatic process ,Randomness - Abstract
We have numerically studied a non-adiabatic charge transport in the quantum Hall system pumped by a magnetic flux, as one of the simplest theoretical realizations of non-adiabatic Thouless pumping. In the adiabatic limit, a pumped charge is quantized, known as Laughlin's argument in a cylindrical lattice. In a uniform electric field, we obtained a formula connecting quantized pumping in the adiabatic limit and no-pumping in the sudden limit. The intermediate region between the two limits is determined by the Landau gap. A randomness or impurity effect is also discussed., Comment: 4 pages, 6 figures
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- 2008
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44. Quantized Berry Phases of a Spin-1/2 Frustrated Two-Leg Ladder with Four-Spin Exchange
- Author
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Yasuhiro Hatsugai, Isao Maruyama, and T. Hirano
- Subjects
Physics ,History ,Condensed matter physics ,Strongly Correlated Electrons (cond-mat.str-el) ,Diagonal ,Exchange interaction ,FOS: Physical sciences ,Berry ,Computer Science Applications ,Education ,symbols.namesake ,Condensed Matter - Strongly Correlated Electrons ,Geometric phase ,symbols ,Antiferromagnetism ,Condensed Matter::Strongly Correlated Electrons ,Hamiltonian (quantum mechanics) ,Direct product - Abstract
A spin-1/2 frustrated two-leg ladder with four-spin exchange interaction is studied by quantized Berry phases. We found that the Berry phase successfully characterizes the Haldane phase in addition to the rung-singlet phase, and the dominant vector-chirality phase. The Hamiltonian of the Haldane phase is topologically identical to the S=1 antiferromagnetic Heisenberg chain. Decoupled models connected to the dominant vector-chirality phase revealed that the local object identified by the non-trivial ($\pi$) Berry phase is the direct product of two diagonal singlets., Comment: 4 pages, 3 figures
- Published
- 2008
- Full Text
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45. U(1)symmetry breaking in one-dimensional Mott insulators studied by the density matrix renormalization group method
- Author
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Yasuhiro Hatsugai, Isao Maruyama, and Tetsuji Koide
- Subjects
Physics ,Explicit symmetry breaking ,Condensed matter physics ,Spontaneous symmetry breaking ,Quantum mechanics ,Mott insulator ,Density matrix renormalization group ,Charge (physics) ,Symmetry breaking ,Condensed Matter Physics ,Chiral symmetry breaking ,Symmetry (physics) ,Electronic, Optical and Magnetic Materials - Abstract
A new type of external fields violating the particle number preservation is studied in one-dimensional strongly correlated systems by the Density Matrix Renormalization Group method. Due to the U(1) symmetry breaking, the ground state has fluctuation of the total particle number, which implies injection of electrons and holes from out of the chain. This charge fluctuation can be relevant even at half-filling because the particle-hole symmetry is preserved with the finite effective field. In addition, we discuss a quantum phase transition obtained by considering the symmetry-breaking fields as a mean field of interchain-hopping.
- Published
- 2007
46. Nontrivial quantized Berry phases for itinerant spin liquids
- Author
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Yasuhiro Hatsugai and Isao Maruyama
- Subjects
Physics ,Quantization (physics) ,Condensed Matter - Strongly Correlated Electrons ,Condensed matter physics ,Geometric phase ,Strongly Correlated Electrons (cond-mat.str-el) ,General Physics and Astronomy ,FOS: Physical sciences ,Berry ,Electron - Abstract
Quantized Berry phases as local order parameters in t-J models are studied. A texture pattern of the local order parameters is topologically stable due to the quantization of non-Abelian Berry phases defined by low-energy states below a spin gap, which exists in the large J/t case with a few electrons. We have confirmed that itinerant singlets in the wide class of t-J models carry the nontrivial Berry phase pi. In the large J/t case for the one-dimensional t-J model, Berry phases are uniformly pi when the number of electrons is N =4n +2, ($n=0,1,2,...$)., 8 pages, 4 figures
- Published
- 2007
47. Levitation and percolation in quantum Hall systems with correlated disorder
- Author
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Isao Maruyama, Yasuhiro Hatsugai, and Hui Song
- Subjects
Physics ,Condensed matter physics ,Condensed Matter - Mesoscale and Nanoscale Physics ,Filling factor ,Thermal Hall effect ,Charge density ,FOS: Physical sciences ,Disordered Systems and Neural Networks (cond-mat.dis-nn) ,Quantum Hall effect ,Condensed Matter - Disordered Systems and Neural Networks ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,Quantum spin Hall effect ,Quantum mechanics ,Percolation ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,Levitation ,ComputingMethodologies_DOCUMENTANDTEXTPROCESSING ,Lattice model (physics) - Abstract
We investigate the integer quantum Hall system in a two dimensional lattice model with spatially correlated disorder by using the efficient method to calculate the Chern number proposed by Fukui et al. [J. Phys. Soc. Jpn. 74, 1674 (2005)]. Distribution of charge density indicates that the extended states at the center of each Landau band have percolating current paths, which are topologically equivalent to the edge states that exist in a system with boundaries. As increasing the strength of disorder, the floating feature is observed in an averaged Hall conductance as a function of filling factor. Its relation to the observed experiments is also discussed.
- Published
- 2007
- Full Text
- View/download PDF
48. Theory of Fano-Kondo effect in quantum dot systems: temperature dependence of the Fano line shapes
- Author
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Naokazu Shibata, Isao Maruyama, and Kazuo Ueda
- Subjects
Physics ,Density matrix ,Condensed matter physics ,Condensed Matter - Mesoscale and Nanoscale Physics ,Density matrix renormalization group ,Conductance ,FOS: Physical sciences ,Fano plane ,Condensed Matter Physics ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Electronic, Optical and Magnetic Materials ,Mathematics::Algebraic Geometry ,Quantum dot ,Quantum mechanics ,Feshbach–Fano partitioning ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,Condensed Matter::Strongly Correlated Electrons ,Kondo effect ,Electrical and Electronic Engineering ,Line (formation) - Abstract
The Fano-Kondo effect in zero-bias conductance is studied based on a theoretical model for the T-shaped quantum dot by the finite temperature density matrix renormalization group method. The modification of the two Fano line shapes at much higher temperatures than the Kondo temperature is also investigated by the effective Fano parameter estimated as a fitting parameter., Comment: 2 pages, 2 figures, the proceeding of SCES'05
- Published
- 2006
- Full Text
- View/download PDF
49. Theory of Fano-Kondo effect of transport properties through quantum dots
- Author
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Isao Maruyama, Kazuo Ueda, and Naokazu Shibata
- Subjects
Physics ,Condensed matter physics ,Condensed Matter - Mesoscale and Nanoscale Physics ,Density matrix renormalization group ,Crossover ,General Physics and Astronomy ,Conductance ,FOS: Physical sciences ,Fano plane ,Function (mathematics) ,Plateau (mathematics) ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Mathematics::Algebraic Geometry ,Quantum dot ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,Condensed Matter::Strongly Correlated Electrons ,Kondo effect - Abstract
The Fano-Kondo effect in zero-bias conductance is investigated based on a theoretical model for the T-shaped quantum dot. The conductance as a function of the gate voltage is generally characterized by a Fano asymmetric parameter q. With varying temperature the conductance shows a crossover between the high and low temperature regions compared with the Kondo temperature T_K: two Fano asymmetric peaks at high temperatures and the Fano-Kondo plateau inside a Fano peak at low temperatures. Temperature dependence of conductance is calculated numerically by the Finite temperature density matrix renormalization group method (FT-DMRG)., 8 pages, 7 figures
- Published
- 2004
50. Induction of hepatic injury by hepatitis C virus-specific CD8+ murine cytotoxic T lymphocytes in transgenic mice expressing the viral structural genes
- Author
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Yoshihiko Norose, Michinori Kohara, Teruo Takano, Hidemi Takahashi, Yohko Nakagawa, Takaji Wakita, Shun Takaku, Masumi Shimizu, and Isao Maruyama
- Subjects
Cytotoxicity, Immunologic ,Genes, Viral ,Hepatitis C virus ,Transgene ,Biophysics ,chemical and pharmacologic phenomena ,Mice, Transgenic ,Hepacivirus ,Biology ,CD8-Positive T-Lymphocytes ,Major histocompatibility complex ,medicine.disease_cause ,Biochemistry ,Adenoviridae ,Cell Line ,Mice ,Viral Proteins ,Immune system ,Interferon ,medicine ,Cytotoxic T cell ,Animals ,Transgenes ,Molecular Biology ,Viral Structural Proteins ,Mice, Inbred BALB C ,Integrases ,Structural gene ,virus diseases ,Cell Biology ,Virology ,Molecular biology ,digestive system diseases ,Liver ,biology.protein ,Hepatocytes ,Female ,CD8 ,medicine.drug - Abstract
In the present study, we generated killer cells specific for hepatitis C virus (HCV) structural protein by re-stimulation of immune spleen cells from H-2 d haplotype transgenic (Tg) mice, expressing the core, E1, E2, and NS2 genes of HCV regulated by the Cre/loxP switching system. The generated killer cells were conventional CD8 + L d class-I MHC molecule-restricted cytotoxic T lymphocytes (CTLs) and specific for the HCV E1 structural protein. Because the CTLs could also kill hepatocytes from the Tg mice expressing HCV structural proteins in vitro, we attempted to transfer those CTLs intravenously into interferon regulatory factor-1 (IRF-1) negative, CD8-deficient Tg mice representing the HCV structural genes on hepatocytes to examine whether the inoculated CD8 + CTLs can eliminate hepatocytes expressing the HCV genes in vivo. We observed an elevation of serum ALT level as well as damage of the liver tissue histologically. To our knowledge, this is the first demonstration to show that HCV-specific CD8 + CTLs specifically attack hepatocytes expressing the HCV structural proteins both in vitro and in vivo.
- Published
- 2003
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