著者

IZUNAGA Yoichi YAMAMOTO Yoshitsugu

出版者

University of Tsukuba. Graduate School of Systems and Information Engineering. Doctoral Program in Social Systems & Management

巻号頁・発行日

2013-07

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The modularity proposed by Newman and Girvan is the most commonly used measure when the nodes of a graph are grouped into communities consisting of tightly connectednodes. We formulate the modularity maximization problem as a set partitioning problem, and propose an algorithm for the problem based on the linear programming relaxation. We solve the dual of the linear programming relaxation by using a cutting plane method. To mediate the slow convergence that cutting plane methods usually suffer, we propose a method for finding and simultaneously adding multiple cutting planes which may complement well each other.

著者

Tabata Kenichi Sasaki Takayuki Yamamoto Yohei

出版者

American Institute of Physics

雑誌

Applied physics letters (ISSN:00036951)

巻号頁・発行日

vol.103, no.4, pp.043301, 2013-07

被引用文献数

9

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Organic semiconductor thin films were fabricated by thermal deposition of free-base and metal phthalocyanines under a static magnetic field. A vertical magnetic field enhanced the crystallinity of the edge-on orientation of the phthalocyanine discs, whereas a horizontal magnetic field had a minimal effect on the crystallinity. The major factor for the orientation change is attributed to the diamagnetic anisotropies of π-electrons in the phthalocyanine macrocycles. Field-effect transistors of phthalocyanine films fabricated under a vertical magnetic field exhibited better hole mobilities and on-current values with smaller threshold voltages than those of phthalocyanine films fabricated without a magnetic field.

著者

by K. Yamamoto

出版者

Niwa

巻号頁・発行日

1873

著者

Klemm Richard A. Delfanazari Kaveh Tsujimoto Manabu Kashiwagi Takanari Kitamura Takeo Yamamoto Takashi Sawamura Masashi Ishida Kazuya Hattori Toshiaki Kadowaki Kazuo

出版者

Elsevier

雑誌

Physica. C, Superconductivity and its applications (ISSN:09214534)

巻号頁・発行日

vol.491, pp.30-34, 2013-08

被引用文献数

19 3

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In order to understand the radiation observed from the intrinsic Josephson junctions in triangular Bi2Sr2CaCu2O8+δ mesas, we calculate the transverse magnetic (TM) electromagnetic modes for thin equilateral cavities. A new set of distinct but degenerate TM modes coexists with the known modes of Helszajn and James, but are expected to lead to distinct radiation angular distribution patterns. Although we have been unable to solve for the exact TM modes of a thin cavity of general acute isosceles triangular shape, we solved exactly the closely related problems of the TM cavity modes of two thin circumscribing “pie-shaped” wedges, which provide highly accurate approximations to very acute isosceles triangular cavities.

著者

Benseman T. M. Gray K. E. Koshelev A. E. Kwok W.-K. Welp U. Minami H. Kadowaki K. Yamamoto T.

出版者

American Institute of Physics

雑誌

Applied physics letters (ISSN:00036951)

巻号頁・発行日

vol.103, no.02, pp.022602, 2013-07

被引用文献数

107 8

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Stacks of intrinsic Josephson junctions in high-temperature superconductors enable the fabrication of compact sources of coherent terahertz radiation. Here, we demonstrate that multiple stacks patterned on the same Bi2Sr2CaCu2O8+δ crystal can—under optimized conditions—be synchronized to emit high-power THz-radiation. For three synchronized stacks, we achieved 610 μW of continuous-wave coherent radiation power at 0.51 THz. We suggest that synchronization is promoted by THz-waves in the base crystal. We note that synchronization cannot be achieved in all samples. However even in these cases, powers on the 100-μW scale can be generated.

著者

Nathalie TOUBLANC Brigitte D LACROIX Junichi YAMAMOTO

出版者

日本薬物動態学会 会長/日本薬物動態学会 DMPK編集委員長

雑誌

Drug Metabolism and Pharmacokinetics (ISSN:13474367)

巻号頁・発行日

pp.DMPK-13-RG-045, (Released:2013-07-23)

参考文献数

32

被引用文献数

20

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Levetiracetam [E Keppra®] is a second generation antiepileptic drug for different types of epilepsy in adults and children ≥1 month. The objective is to develop a population pharmacokinetic model to describe the pharmacokinetics of levetiracetam in Japanese children and adults as well as North American children, the purpose being to explore potential dosing recommendations in Japanese children. Levetiracetam plasma concentration-time data were obtained from Japanese adult and paediatric clinical studies. The data were analysed through non-linear mixed effects modelling. The model was used to perform simulations and compare the exposure in Japanese children and adults. It was subsequently extended to North American children through an external validation. A one-compartment model with first-order absorption and first-order elimination adequately described the data. The exposure parameters determined based on the simulations in children were well within the adult range. The external validation against historical data from North American children was successful. The integrated population pharmacokinetic model provided a good description of the data, confirming the similarity of levetiracetam pharmacokinetics in these various populations. In Japanese children, a target dose of 10 to 30 mg/kg twice daily ensures the same exposure as the recommended dose in Japanese adults of 500 to 1500 mg twice daily.

著者

Kazuhiro YAMADA Nozomi MAEDA Junko NOGUCHI Hideaki YAMADA Emi MORINAGA Hitomi YATAKE Yuji YAMAMOTO Tadahiro TADOKORO Tetsunori KAWATA

出版者

Center for Academic Publications Japan

雑誌

Journal of Nutritional Science and Vitaminology (ISSN:03014800)

巻号頁・発行日

vol.59, no.3, pp.238-242, 2013 (Released:2013-07-25)

参考文献数

23

被引用文献数

3 5

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The influence of maternal vitamin B12 malnutrition on testicular development of offspring was examined using soy protein-based B12-deficient diets with or without 0.5% DL-methionine supplementation. Dams were fed the B12-deficient diet throughout gestation and lactation, whereas dams in a control group were fed a control diet which contained cyanocobalamin in the B12-deficient diet without methionine. Offspring born to dams fed the B12-deficient diet without methionine showed poor testicular development, e.g. decreased numbers of seminiferous tubules containing healthy spermatocytes and a high ratio of apoptotic cells per all germ cells. The abnormality was rarely observed in the group fed the B12-deficient diet with methionine. It was likely that the testicular abnormality of offspring was caused by B12-deficiency post partum and was prevented by the methionine supplementation. These observations suggested that maternal B12 nutritional status during the pre-weaning period is quite important for spermatogenesis of male offspring and that the requirement of B12 for testicular development is to produce active B12-dependent methionine synthase.

著者

Yamamoto Ikuo Iio Katsunori Nagata Kazukiyo

出版者

一般社団法人日本物理学会

雑誌

Journal of the Physical Society of Japan (ISSN:00319015)

巻号頁・発行日

vol.49, no.5, pp.1756-1759, 1980-11-15

被引用文献数

6

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Magnetic anisotropies of several mangane secryst,als have been naeasured accu-rately between 77 K and 300 K by using a high sensitive torque-naeter. ,As ispredicted by the high temperature expansion th<cory, the observed naagneticanisotropies vary as the inverse square of the tempe.rature. The crystal field split-ting parameters D and E have been obtained for<>ach pure magnetically densesanuple. In compounds having the octahedron witla two water molecules alongthe axial direction, the splitting parameters D have been found to be about -0.1cm-', which value is two tiznes or one order of mag;nitude larger than the typicalvalue of Mn" surrounded by a distorted octaheclron composed of six si.milarligands. Especially, the value 17)l =0.368 cm ' fo'ar [(CH.).NlI]MnBr.2I-[.0 isthe largest one reported to date.

著者

山本 修 沢田 昭三 吉永 春馬 ヤマモト オサム サワダ ショウゾウ ヨシナガ ハルマ Yamamoto Osamu Sawada Shozo Yoshinaga Haruma

出版者

日本医学放射線学会

雑誌

日本医学放射線学会雑誌 (ISSN:00480428)

巻号頁・発行日

vol.23, no.2, pp.141-145, 1963-05-25

著者

河合 一武 高藤 順 太田 真司 黒澤 尚 山本 大 北上 優 Kazutake Kawai Jun Takafuji Shinji Ota Takashi Kurosawa Dai Yamamoto Yu Kitakami

出版者

武蔵丘短期大学

雑誌

武蔵丘短期大学紀要 (ISSN:13413120)

巻号頁・発行日

vol.19, pp.155-159, 2011

著者

Patrick C. CABAITAN Hiromi YAMAMOTO Kazuhiko SAKAI

出版者

日本サンゴ礁学会

雑誌

Galaxea, Journal of Coral Reef Studies (ISSN:18830838)

巻号頁・発行日

vol.14, no.1, pp.27-40, 2012 (Released:2013-03-22)

参考文献数

33

被引用文献数

1 7

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Coral communities at nine sites off the coast of Motobu, Okinawa, were examined 6 and 12 years after a 1998 mass coral bleaching event caused by anomalous seawater temperatures. Overall, mean coral coverage increased from 17% in 2006 to 28% in 2010 at these sites, although these percentages were lower than the coral coverage at a nearby reef at Sesoko Island. Some of the corals that had not recovered (the “losers”) at the Sesoko reef were found at some sites in the present study. Dominant coral taxa differed among sites, probably because of differences in the environmental conditions at the sites, e.g., the so-called massive-type coral Porites dominated at a protected site near a river, while branching-type Acropora was dominant at exposed sites. Acropora was one of the prominent short-term losers, but contributed significantly to coral coverage increases due to its fast growth at some exposed sites. Adjacent reefs, which may share similar environmental conditions, also showed some variability, possibly due to processes such as coral recruitment and post settlement survival, which acted on a smaller spatial scale. Multivariate analyses such as multidimensional scaling were more sensitive than univariate analyses. Overall, recruitment was low, especially at sites with high coral coverage, which implies that remnant corals may have contributed to the recovery of these reefs. Coral communities in this area are recovering and there has been no apparent shift to algae-dominated communities. The recovery of coral communities appears to be related to the life history traits of corals and environmental conditions.

著者

Yamamoto Tsuyoshi Nakamura Atsuko Iwai Hiroaki Ishii Tadashi Ma Jian Feng Yokoyama Ryusuke Nishitani Kazuhiko Satoh Shinobu Furukawa Jun

出版者

Springer Japan

雑誌

Journal of plant research (ISSN:09189440)

巻号頁・発行日

vol.125, no.6, pp.771-779, 2012-11

被引用文献数

64 3

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Rice (Oryza sativa L.) is a typical Si-accumulating plant and is able to accumulate Si up to >10 % of shoot dry weight. The cell wall has been reported to become thicker under Si-deficient condition. To clarify the relationship between Si accumulation and cell wall components, the physical properties of, and macromolecular components and Si content in, the pectic, hemicellulosic, and cellulosic fractions prepared from rice seedlings grown in hydroponics with or without 1.5 mM silicic acid were analyzed. In the absence of Si (the −Si condition), leaf blades drooped, but physical properties were enhanced. Sugar content in the cellulosic fraction and lignin content in the total cell wall increased under −Si condition. After histochemical staining, there was an increase in cellulose deposition in short cells and the cell layer just beneath the epidermis in the −Si condition, but no significant change in the pattern of lignin deposition. Expression of the genes involved in secondary cell wall synthesis, OsCesA4, OsCesA7, OsPAL, OsCCR1 and OsCAD6 was up-regulated under −Si condition, but expression of OsCesA1, involved in primary cell wall synthesis, did not increase. These results suggest that an increase in secondary cell wall components occurs in rice leaves to compensate for Si deficiency.

著者

Chihiro AKIBA Takanori ESAKI Maya ANDO Tsuyoshi FURUYA Kazuyuki NODA Yasuaki NAKAO Takuji YAMAMOTO Yasuyuki OKUMA Kentaro MORI

出版者

社団法人 日本脳神経外科学会

雑誌

Neurologia medico-chirurgica (ISSN:04708105)

巻号頁・発行日

vol.51, no.2, pp.140-143, 2011 (Released:2011-02-25)

参考文献数

9

被引用文献数

2 5

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A 62-year-old male presented with a rare case of possible neuro-Sweet Disease (NSD) mimicking brain tumor in the medulla oblongata, manifesting as numbness in the bilateral upper and lower extremities, gait disturbance, dysarthria, and swallowing disturbance which gradually deteriorated over 3 months. Magnetic resonance imaging showed a mass lesion in the medulla oblongata, extending to the upper cervical cord with rim enhancement by gadolinium. The preoperative diagnosis was brain tumor, such as glioma, or inflammatory disease. His neurological symptoms gradually deteriorated, so biopsy was performed through the midline suboccipital approach. Histological examination showed infiltration of inflammatory cells, mainly lymphocytes and macrophages. Human leukocyte antigen typing showed Cw1 and B54 which strongly suggested possible NSD. Steroid pulse therapy was started after surgery and the clinical symptoms improved. Neurosurgeons should be aware of inflammatory disorders such as NSD mimicking brain tumor.

著者

Sota Teiji Yamamoto Satoshi Cooley John R Hill Kathy B R Simon Chris Yoshimura Jin

出版者

National Academy of Sciences

雑誌

Proceedings of the National Academy of Sciences of the United States of America (ISSN:10916490)

巻号頁・発行日

2013-03-18

被引用文献数

48

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昆虫で最も不思議な生活史を持つ北米の周期ゼミの進化史を解明. 京都大学プレスリリース. 2013-03-19.

著者

Yoshimi NIWANO Takashi ADACHI Jun KASHIMURA Takashi SAKATA Hajime SASAKI Kazunori SEKINE Satoshi YAMAMOTO Akie YONEKUBO Shuichi KIMURA

出版者

Center for Academic Publications Japan

雑誌

Journal of Nutritional Science and Vitaminology (ISSN:03014800)

巻号頁・発行日

vol.55, no.3, pp.201-207, 2009 (Released:2009-07-15)

参考文献数

41

被引用文献数

18 46

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This review assesses the feasibility of using glycemic index (GI) as a predictor of appetite, hunger and satiety by surveying published human intervention studies. We also discuss the relationship between GI and two appetite/satiety control hormones, leptin and ghrelin. Ingestion of high-GI food increased hunger and lowered satiety in short-term human intervention studies. This effect may be attributed to the rapid decline in blood glucose level following a hyperinsulinemic response caused by a sharp and transient increase in blood glucose level that occurs after the ingestion of high-GI food, which is defined as the glucostatic theory. However, appetite, hunger and satiety after the ingestion of foods with varying GI were inconsistent among long-term human intervention studies. From the few relevant long-term studies available, we selected two recent well-designed examples for analysis, but they failed to elicit clear differences in glycemic and insulinemic responses between high- and low-GI meals (consisting of a combination of different foods or key carbohydrate-rich foods incorporated into habitual diets). One of the reasons that these studies could not predict glycemic response to mixed meals is presumably that the GI of each particular food was not reflected in that of the mixed meals as a whole. Thus, it is difficult to conclude that the GI values of foods or mixed meals are a valid long-term predictor for appetite, hunger and satiety. Both insulin and insulin-mediated glucose uptake and metabolism in adipose tissue affect blood leptin concentration and its diurnal pattern. Circulating ghrelin level is suppressed by carbohydrate-rich meals, presumably via glycemia and insulinemia. Accordingly, low-GI foods may not necessarily increase satiety or suppress appetite and/or hunger because of the lack of insulin-mediated leptin stimulation and ghrelin suppression. However, insulin-mediated leptin stimulation and ghrelin suppression per se is not consistent among studies; thus we were not able to identify a clear relationship among GI, satietogenic leptin, and appetitic ghrelin.

著者

IGARASHI Ayumi YAMAMOTO Yoshitsugu

出版者

University of Tsukuba. Graduate School of Systems and Information Engineering. Doctoral Program in Social Systems & Management

巻号頁・発行日

2012-11

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In this paper we prove that calculating the average covering tree valuerecently proposed as a single-valued solution of graph games is #P-complete.

著者

Hajime KAYANNE Chuki HONGO Ken OKAJI Yoichi IDE Takeshi HAYASHIBARA Hidekazu YAMAMOTO Nobuo MIKAMI Kiyoshi ONODERA Takaaki OOTSUBO Hiroyuki TAKANO Makoto TONEGAWA Shogo MARUYAMA

出版者

日本サンゴ礁学会

雑誌

Galaxea, Journal of Coral Reef Studies (ISSN:18830838)

巻号頁・発行日

vol.14, no.1, pp.73-95, 2012 (Released:2013-02-04)

参考文献数

37

被引用文献数

1 7 1

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Ninety-three coral species have been identified at Okinotorishima (Okinotori Island), an isolated table reef located in the center of the Philippine Sea. The species composition of the island is similar to that of other islands in the northwestern Pacific, but the number of species is small in comparison with surrounding islands. The coral fauna at the island is characterized by a unique species composition that is independent of the Ryukyu Islands, mainland Japan, Palau, and the Mariana Islands. No endemic species were found, but the dominant Acropora species (A. aculeus, A. sp. aff. divaricata, and A. globiceps) were morphologically different from corresponding species at the Ryukyu Islands. The relatively low species diversity at the island despite the close proximity to an area of high diversity is explained by its small habitat diversity and isolation from other islands. The island is located in a subtropical gyre and is isolated from major currents. Thus, only coral larvae with a long competency period (as long as 70 days) can settle at the island from surrounding islands. This unique species composition seems to have been maintained for at least the last 7600 years, since the last stage of sea level rise in the post-glacial period (Holocene).

著者

Hirai H. Tanaka T. Kawamura T. Yamamoto Y. Yagi T.

出版者

American Physical Society

雑誌

Physical review B (ISSN:10980121)

巻号頁・発行日

vol.68, no.17, pp.172102, 2003-11

被引用文献数

53 45

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High-pressure experiments on methane hydrate were performed in the pressure range of 0.2–42 GPa using diamond-anvil cell. In situ x-ray-diffraction study revealed that methane hydrate of a high-pressure form, filled ice structure, survived up to 42 GPa. Pressure versus volume data were obtained in the pressure region. The filled ice structure represented large anisotropic compressibility and the volume change attained 40% at 42 GPa. The anisotropic compressibility was explained by the characteristic channel framework of the filled ice structure.

著者

Yamamoto Susumu Fujiwara Takeo Hatsugai Yasuhiro

出版者

American Physical Society

雑誌

Physical review B (ISSN:10980121)

巻号頁・発行日

vol.76, no.16, pp.165114, 2007-10

被引用文献数

26 16

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Electronic structure of stripe ordered La2−xSrxNiO4 is investigated. The system with x=(1/3) is insulator, in LSDA+U calculations, and shows charge and spin stripe, consistent with the experimental results. A highly correlated system of x=(1/2) is studied by using exact diagonalization of the multiorbital many-body Hamiltonian derived from LDA calculations and including on-site and intersite Coulomb interactions. The fluctuation of the residual spin on Ni3+ (hole) site couples with the charge fluctuation between Ni3+ and Ni2+ states and this correlation lowers the total energy. The resultant ground state is an insulator with charge and spin stripe of the energy gap 0.9 eV, consistent with the observed one. The on-site Coulomb interaction stabilizes integral valency of each Ni ion (Ni3+ and Ni2+), but does not induce the charge order. Two quantities, intersite Coulomb interaction and anisotropy of hopping integrals, play an important role to form the charge and spin stripe order in a system of x=(1/2).

著者

Turkoglu F Koseoglu H Demirhan Y Ozyuzer L Preu S Malzer S Simsek Y Müller P Yamamoto T Kadowaki K

出版者

IOP Publishing

雑誌

Superconductor science & technology (ISSN:09532048)

巻号頁・発行日

vol.25, no.12, pp.125004, 2012-10

被引用文献数

39 16

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We fabricated rectangular mesa structures of superconducting Bi2Sr2CaCu2O8+d (Bi2212) using e-beam lithography and Ar ion beam etching techniques for terahertz (THz) emission. c-axis resistance versus temperature (R–T), current–voltage (I–V) characteristics and bolometric THz power measurements were performed to characterize Bi2212 mesas. The emission frequency of mesas was determined using a Michelson interferometer setup which also demonstrates polarized emission. Interference patterns of THz radiation from Bi2212 mesas were detected by various detectors such as a liquid helium cooled silicon composite bolometer, a Golay cell and a pyroelectric detector. An emitted power as high as 0.06 mW was detected from Bi2212 mesas. For the first time, most of the pumped power was extracted as THz emission from a Bi2212 mesa. The radiation at 0.54 THz was detected using the Michelson interferometric setup.