Hokkaido University , or Hokudai , is one of the national universities of Japan. It is a member of the National Seven Universities, which were established as the best national higher education or research institute. It is located in downtown Sapporo, just north of Sapporo Station, and stretching approximately 2.4 kilometers northward. It is considered as one of the top universities in Japan. Wikipedia.
Heki K.,Hokkaido University
Geophysical Research Letters | Year: 2011
The 2011 March 11 Tohoku-Oki earthquake (Mw9.0) caused vast damages to the country. Large events beneath dense observation networks could bring breakthroughs to seismology and geodynamics, and here I report one such finding. The Japanese dense network of Global Positioning System (GPS) detected clear precursory positive anomaly of ionospheric total electron content (TEC) around the focal region. It started ∼40 minutes before the earthquake and reached nearly ten percent of the background TEC. It lasted until atmospheric waves arrived at the ionosphere. Similar preseismic TEC anomalies, with amplitudes dependent on magnitudes, were seen in the 2010 Chile earthquake (Mw8.8), and possibly in the 2004 Sumatra-Andaman (Mw9.2) and the 1994 Hokkaido-Toho-Oki (Mw8.3) earthquakes, but not in smaller earthquakes. Copyright 2011 by the American Geophysical Union.
Takahashi H.,Hokkaido University
Earth, Planets and Space | Year: 2011
The 2011 M 9.0 Tohoku earthquake induced regional crustal deformation not only in the Japanese Islands but also in north-eastern Asia. Strain release due to mainshock faulting should cause strain redistribution in the overriding plates. The dense GPS network in Japan enables us to calculate co-seismic strain and stress changes from observed data. Strain is a more objective indicator than displacement because no reference frame is required. The co-seismic strain field clearly indicates island-scale strain redistribution. Huge extensional strain changes were concentrated in the southern Iwate and northern Miyagi regions, with a maximum value of 45 × 10 -6, which might correspond to approximately 225 to 450 years of strain accumulation. This implies relatively large strain accumulation and release in these regions. Small strain decay was observed in the northernmost Niigata- Kobe tectonic zone and a possible anomalous Coulomb failure stress change was observed in the Mt. Fuji region. Earthquakes triggered in the above regions might be associated with these anomalies, and/or these non-uniform crustal deformations may reflect crustal heterogeneity. Copyright © The Society of Geomagnetism and Earth, Planetary and Space Sciences (SGEPSS).
Shimada T.,Tohoku University |
Minobe S.,Hokkaido University
Geophysical Research Letters | Year: 2011
We investigate the signatures of atmospheric pressure adjustment mechanism for surface wind convergence/divergence over major sea surface temperature (SST) frontal regions using global observations of satellite sounding and scatterometer. Lower tropospheric air thickness, which includes a sea-level pressure component modified by air temperature in the marine atmospheric boundary layer, is analyzed, and the relation between the Laplacian of the thickness and wind convergence are examined. Among four SST frontal regions in mid-latitudes, correlation between the thickness Laplacian and wind convergence is the largest over the Gulf Stream followed by those for the Agulhas Return Current and for the Brazil/Malvinas Current, and relatively small but still significant over the Kuroshio-Oyashio Extension. These correlations strongly suggest that the pressure adjustment mechanism ubiquitously plays an important role in air-sea interaction over the global SST frontal regions. Furthermore, air temperatures in the first two regions exhibit SST-relating signatures even in the mid-troposphere. Copyright 2011 by the American Geophysical Union.
Kimura N.,University of Tokyo |
Wakatsuchi M.,Hokkaido University
Tellus, Series A: Dynamic Meteorology and Oceanography | Year: 2011
The seasonal variability of sea-ice cover in the Southern Ocean is examined using daily sea-ice concentration and ice velocity products for 2003-2009, derived from Advanced Microwave Scanning Radiometer for EOS (AMSR-E) data. This study quantitatively shows the contribution of (1) ice production/reduction within the sea ice, (2) ice production/reduction at the sea-ice edge and (3) zonal ice transport to the seasonal change of sea-ice area. Area of greatest ice production occurs along the coast of Ross Sea and East Antarctica from March to September. The contribution of zonal transport to the seasonal change of ice area is one order magnitude smaller than local ice production/reduction. Clear regional and seasonal differences are found in the large-scale processes named above. Generally, ice area increases due to ice production, both at the ice edge and within the pack in the autumn and winter. The most significant ice production at the ice edge occurred in the Weddell Sea; the ice production provides 56% of total increase of ice cover in this area. In contrast, moderate ice melting occurs at the ice edge through almost all months in the Indian Ocean sector. ©2011 The Authors Tellus A©2011 John Wiley & Sons A/S.
Katsumata K.,Hokkaido University
Earth, Planets and Space | Year: 2011
I find that a long-term seismic quiescence started 23.4 years before the 2011 off the Pacific coast of Tohoku Earthquake (M = 9.0). An earthquake catalog compiled by the Japan Meteorological Agency (JMA) is analyzed. The catalog includes 5770 earthquakes shallower than 60 km with M ≥ 4.5. A detailed analysis of the earthquake catalog between 1965 and 2010 using the gridding technique ZMAP shows that the 2011 Tohoku earthquake is preceded by a seismic quiescence anomaly that began in November 1987. The quiescence-anomaly area is located around the deeper edge of the asperity ruptured by the main shock, and the Z-value is +4.9 for a time window of Tw = 15 years, using a sample size of A7 = 150 earthquakes. It is suggested that a seismic quiescence which starts more than 20 years before the main shock is common to giant earthquakes (M ∼ 9.0) in subduction zones. Copyright © The Society of Geomagnetism and Earth, Planetary and Space Sciences (SGEPSS).
Kawashima M.,Hokkaido University
Journal of the Atmospheric Sciences | Year: 2011
The effects of variations in low-level ambient vertical shear and horizontal shear on the alongfront variability of narrow cold frontal rainbands (NCFRs) that propagate into neutral and slightly unstable environments are investigated through a series of idealized cloud-resolving simulations. In cases initialized with slightly unstable sounding and weak ambient cross-frontal vertical shears, core-gap structures of precipitation along NCFRs occur that are associated with wavelike disturbances that derive their kinetic energy mainly from the mean local vertical shear and buoyancy. However, over a wide range of environmental conditions, core-gap structures of precipitation occur because of the development of a horizontal shear instability (HSI) wave along the NCFRs. The growth rate and amplitude of the HSI wave decrease significantly as the vertical shear of the ambient cross-front wind is reduced. These decreases are a consequence of the enhancement of the low-level local vertical shear immediately behind the leading edge. The strong local vertical shear acts to damp the vorticity edge wave on the cold air side of the shear zone, thereby suppressing the growth of the HSI wave through the interaction of the two vorticity edge waves. It is also noted that the initial wavelength of theHSI wave increases markedly with increasing horizontal shear. The local vertical shear around the leading edge is shown to damp long HSI waves more strongly than short waves, and the horizontal shear dependency of the wavelength is explained by the decrease in the magnitude of the vertical shear relative to that of the horizontal shear. © 2011 American Meteorological Society.
Iba T.,Juntendo University |
Gando S.,Hokkaido University |
Thachil J.,Royal Infirmary
Journal of Thrombosis and Haemostasis | Year: 2014
The current management of disseminated intravascular coagulation (DIC) is based on aggressive treatment of the underlying condition and resuscitation with appropriate blood products. Anticoagulant therapy has appeared and disappeared in the different guidelines and important documents detailing the treatment of DIC. For example, Surviving Sepsis Campaign (SSC) guidelines, the 'global standard' for the management of severe sepsis, had recombinant activated protein C highly recommended in the original version, but this was withdrawn in the latest version due to the lack of evidence. In contrast, recent international guidance released from the International Society on Thrombosis and Haemostasis has introduced the potential efficacy of other agents. In sepsis-related DIC, the basis for anticoagulant therapy comes from the mounting evidence for the anti-inflammatory effects which these agents possess and can prove beneficial in septic situations. Several studies have clearly shown the important cross-talk between coagulation and inflammation in patients with sepsis. More recently, neutrophil extracellular traps and damage-associated molecular patterns (DAMPs), especially histones, have been demonstrated to play a crucial role in the coagulopathy of sepsis. Once again, the natural anticoagulants have an important function in neutralizing the effects of DAMPs and histones. In this review, in addition to examining the important role of anticoagulants in the septic milieu, the clinical studies examining antithrombin, recombinant thrombomodulin and plasma-derived activated protein C are detailed. However, large-scale randomized controlled trials are yet to be performed, with important consideration of the timing, dosage and duration of treatment. © 2014 International Society on Thrombosis and Haemostasis.
Utsumi S.,Hokkaido University |
Ando Y.,Kyoto University |
Roininen H.,University of Eastern Finland |
Takahashi J.-I.,Kyoto Sangyo University |
Ohgushi T.,Kyoto University
Ecology Letters | Year: 2013
Several recent studies have emphasised that community composition alters species trait evolution. Here, we demonstrate that differences in composition of local herbivore communities lead to divergent trait evolution of the leaf beetle Plagiodera versicolora through plant-mediated indirect interactions. Our field surveys, genetic analyses and community-manipulation experiments show that herbivore community composition determines the degree of herbivore-induced regrowth of willows (Salicaceae), which in turn, promotes the divergent evolution of feeding preference in the leaf beetle from exclusive preference for new leaves to a lack of preference among leaf-age types. Regrowth intensity depends both on the differential response of willows to different herbivore species and the integration of those herbivore species in the community. Because herbivore-induced regrowth involves phenological changes in new leaf production, leaf beetle populations develop divergent feeding preferences according to local regrowth intensity. Therefore, herbivore community composition shapes the selection regime for leaf beetle evolution through trait-mediated indirect interactions. © 2012 Blackwell Publishing Ltd/CNRS.
Kikuchi Y.,Japan National Institute of Advanced Industrial Science and Technology |
Kikuchi Y.,Hokkaido University |
Fukatsu T.,Japan National Institute of Advanced Industrial Science and Technology
Molecular Ecology | Year: 2014
Many insects possess endosymbiotic bacteria inside their body, wherein intimate interactions occur between the partners. While recent technological advancements have deepened our understanding of metabolic and evolutionary features of the symbiont genomes, molecular mechanisms underpinning the intimate interactions remain difficult to approach because the insect symbionts are generally uncultivable. The bean bug Riptortus pedestris is associated with the betaproteobacterial Burkholderia symbiont in a posterior region of the midgut, which develops numerous crypts harbouring the symbiont extracellularly. Distinct from other insect symbiotic systems, R. pedestris acquires the Burkholderia symbiont not by vertical transmission but from the environment every generation. By making use of the cultivability and the genetic tractability of the symbiont, we constructed a transgenic Burkholderia strain labelled with green fluorescent protein (GFP), which enabled detailed observation of spatiotemporal dynamics and the colonization process of the symbiont in freshly prepared specimens. The symbiont live imaging revealed that, at the second instar, colonization of the symbiotic midgut M4 region started around 6 h after inoculation (hai). By 24 hai, the symbiont cells appeared in the main tract and also in several crypts of the M4. By 48 hai, most of the crypts were colonized by the symbiont cells. By 72 hai, all the crypts were filled up with the symbiont cells and the symbiont localization pattern continued during the subsequent nymphal development. Quantitative PCR of the symbiont confirmed the infection dynamics quantitatively. These results highlight the stinkbug-Burkholderia gut symbiosis as an unprecedented model for comprehensive understanding of molecular mechanisms underpinning insect symbiosis. © 2013 The Authors. Molecular Ecology Published by John Wiley & Sons Ltd.
Bower J.R.,Hokkaido University
Fisheries Oceanography | Year: 2011
The goal of scientific writing is clear communication of facts and ideas. Many books are available that explain the myriad of English grammar rules but clear communication requires more than just correct grammar; it also requires an understanding of how people read English. This paper briefly describes the structure of English prose and lists four principles to help non-native speakers improve their writing. The first two deal with individual sentences, focusing on the importance of the stress position and the subject-verb link. The final two deal with series of sentences, focusing on the importance of cohesion and coherence. © 2010 Blackwell Publishing Ltd.
Yamazaki K.,Kyoto University |
Yamazaki K.,Hokkaido University
Geophysical Journal International | Year: 2011
To determine whether the piezomagnetic effect is a plausible mechanism in explaining variations in the magnetic field that occur synchronously with the propagation of teleseismic waves, a set of solutions are derived for the electromagnetic field. The situation is considered in which the Earth's conductivity has a stratified structure and seismic waves are expressed as a plane wave. The piezomagnetic field in this situation is expressed by an analytically closed form. Using the obtained solution, quantitative aspects of the piezomagnetic field that accompanies seismic Rayleigh waves are discussed. It is shown that the finite conductivity of the Earth's crust sometimes acts as an enhancer of the magnitude of the piezomagnetic field. However, the expected piezomagnetic field is substantially small. Even in the case that the initial magnetization around the observation site is as large as 5 A m-1, the expected amplitudes in the piezomagnetic field are at most 0.1 nT. This result means that the piezomagnetic effect is not a reasonable mechanism to sufficiently explain variations in magnetic fields that occur synchronously with ground motions, if the initial magnetization is horizontally uniform. © 2010 The Authors Geophysical Journal International © 2010 RAS.
Takahashi R.,Geological Survey of Japan |
Nakagawa M.,Hokkaido University
Journal of Petrology | Year: 2013
Historical eruptive activity commenced at Hokkaido-Komagatake volcano in AD 1640 after about 5000 years of dormancy. The AD 1640 event was followed by another eruption in AD 1694. Petrological investigation of these eruptions provides useful information for understanding the initial state of the magma system and its early evolution. Both events were plinian eruptions in which the ejecta were primarily white pumice (silicic andesite) with lesser amounts of mafic clasts (mafic to intermediate andesite). In both cases the mafic material erupted prior to the silicic.The AD 1640 ejecta are of three types: white pumice, scoria and banded pumice. The whole-rock chemistry of the banded pumice shows a linear chemical trend connecting the white pumice and scoria, which is interpreted to indicate that magma mingling occurred between two end-members. Highly porphyritic white pumice shows no evidence of magma mixing, indicating that this material is directly representative of the silicic end-member magma. Scoria, which is interpreted to represent the mafic end-member magma, is nearly aphyric but the phenocrysts that are present are similar to those contained in the white pumice. In the AD 1640 eruption, the injected mafic magma is inferred to have ascended as a dike into a silicic chamber while mingling; the mafic material was erupted first. In the AD1694 eruption, gray pumice occurs in addition to the other three types of ejecta and this has whole-rock compositions intermediate between those of the white pumice and scoria. In addition, the gray pumice contains phenocrysts with reverse zonation, suggesting that it is a product of mixing between the end-member magmas. These pumices suggest that a zoned magma body was formed during the AD 1640 eruption and that the two contrasting magmas mixed until the AD 1694 eruption. The chamber was compositionally reverse zoned and consisted of upper mafic and lower silicic zones with hybrid layers between them; the silicic magma was strongly porphyritic and thus denser than the aphyric mafic magma. The sequence of the AD 1694 eruption can be explained by sequential ejection from the upper part of the zoned chamber without a new injection of mafic magma. This is consistent with the view that the AD 1694 banded pumice was the product of mingling between the silicic and hybrid magmas and that mafic magma had not interacted with the silicic magma. © The Author 2012. Published by Oxford University Press. All rights reserved.
Fukase H.,Hokkaido University
American Journal of Physical Anthropology | Year: 2014
The mental foramen (MF) of adult human mandibles is characterized by its high position and posterosuperior opening orientation, compared with that of nonhuman primates. In this study, to examine when and how such interspecies variations in MF position/orientation are manifested in the context of dental development, positional relationships between the MF and nearby forming teeth (dc, dm1, C, P3) were assessed using CT-scanned growth-series mandibles of the following three species with various MF positions and anterior dental sizes: modern humans, chimpanzees, and hamadryas baboons. Results showed that modern humans have more antero-superiorly located MF and dc than the two nonhuman samples during growth, whereas the MF and dm1 of hamadryas baboons are the most inferiorly positioned. Considering that the mandibular canal generally reaches the dc/dm1 position during infancy, the species differences in MF position can be attributed largely to the positions where the anterior deciduous teeth first appear. Specifically, the distinctive dental position of modern humans should stem eventually from the comparatively small anterior dental size. Furthermore, human MF position shifted slightly upwards with alveolar development, unlike in the nonhuman samples, accompanied by strong curvature and vertical elongation of the anterior mandibular canal. Meanwhile, the human MF shifted from a forward to a lateral/backward orientation in association with human-specific growth-related alveolar recession. The findings of this study, thus, collectively indicate that taxonomic variations in adult MF position/orientation can be interpreted partly by the positions of the surrounding developing teeth. © 2014 Wiley Periodicals, Inc.
Ghimire M.,Hokkaido University
Natural Hazards | Year: 2011
Landslides in the three studied basins of the Siwalik Hills are not random in distribution; they tend to cluster in certain areas implying the control of certain in situ factors or their combination. Landslide controlling in situ factors were reviewed and analyzed from maps, aerial photos and imageries using GIS. Chi square analysis was carried out to test the significance of landslide distribution vis-à-vis in situ factors. Slope gradient and relative relief were consistently significant in landslide distribution. Geology, dip-topography relation, land use and land cover, and vegetation conditions appeared important in landslide occurrence in all three basins either in terms of area or count in any two basins. Slope aspect and altitude tested significant for landslide occurrence in at least two basins. However, upslope flow contributing area, drainage density and distance to lineament were found insignificant in all three basins. In situ factors that tested significant in any two basins were used for landslide susceptibility analysis using a bivariate statistical approach. The distribution of landslides strongly correlates with susceptibility indices. With in situ factors, landslide susceptibility had good correlation with slope gradient and relative relief. Incorporating calculated factor weight values from one basin to the other two basins, proxy susceptibility index maps were also prepared. A moderate to good positive correlation appeared between them implying certain range of confidence for replicating the result for whole of the Siwalik Hills. Slope gradient and relative relief can be used as proxy indicators of landslide susceptible areas in the Siwalik Hills. © 2010 Springer Science+Business Media B.V.
Heki K.,Hokkaido University |
Enomoto Y.,Toyama Industrial Technology Center
Journal of Geophysical Research: Space Physics | Year: 2013
Possible enhancement of ionospheric Total Electron Content (TEC) immediately before the 2011 Tohoku-oki earthquake (Mw9.0) has been reported by Heki (2011). Critical responses to it often come in two stages; they first doubt the enhancement itself and attribute it to an artifact. Second (when they accept the enhancement), they doubt the significance of the enhancement among natural variability of space weather origin. For example, Kamogawa and Kakinami (2013) attributed the enhancement to an artifact falsely detected by the combined effect of the highly variable TEC under active geomagnetic condition and the occurrence of a tsunamigenic ionospheric hole. Here we closely examine the time series of vertical TEC before and after the 2011 Tohoku-oki earthquake. We first demonstrate that the tsunami did not make an ionospheric hole, and next confirm the reality of the enhancement using data of two other sensors, ionosonde and magnetometers. The amplitude of the preseismic TEC enhancement is within the natural variability, and its snapshot resembles to large-scale traveling ionospheric disturbances. However, distinction could be made by examining their propagation properties. Similar TEC anomalies occurred before all the M ≥ 8.5 earthquakes in this century, suggesting their seismic origin. Key Points Tsunami does not make an ionpsheric hole TEC enhancement, changes in foEs and declination started together All earthquakes exceeding M8.5 are preceded by TEC enhancements ©2013. American Geophysical Union. All Rights Reserved.
Kamogawa M.,Tokyo Gakugei University |
Kakinami Y.,Hokkaido University
Journal of Geophysical Research: Space Physics | Year: 2013
Heki  reported that the TEC gradually enhanced from 40 minutes before the 2011 M9.0 off the Pacific coast of Tohoku earthquake (Tohoku EQ) to the time when the co-seismic acoustic wave reached the ionosphere and the TEC immediately recovered at the normal state. This paper shows an alternative interpretation of total electron content (TEC) variation in the ionosphere associated with the Tohoku EQ. Our interpretation is that a tsunamigenic ionospheric hole, a wide depletion of the TEC, occurred after the co-seismic acoustic wave reached the ionosphere and gradually recovered at the normal state with several tens of minutes [Kakinami et al., 2012]. The difference between Heki  and Kakinami et al.  is attributed to the reference curves of the TEC to extract the ionospheric variations. The former is given by the least-squares fitting curve of the EQ day data excluding an expected precursor period, while the latter is given by the data of the similar orbit of global positioning system (GPS) satellite on another day. The results suggest that variation of slant TEC is explained by the depletion of TEC due to tsunami rather than the precursory enhancement. Key Points A TEC precursory enhancement is found due to an artifact of the analysis.A TEC depletion occurs over the tsunami source area.A tsunamigenic ionospheric hole misled us to a precursor. ©2013. American Geophysical Union. All Rights Reserved.
Yoshimura S.,Hokkaido University |
Nakamura M.,Tohoku University
Earth and Planetary Science Letters | Year: 2013
Volcanic CO2 degassing is considered the primary process that controls the global carbon cycle over geological timescales. However, fluxes of CO2 from individual volcanoes, in particular those in past activities, have been poorly constrained. One way to estimate the flux is by using the H2O-CO2 systematics of melt inclusions, which, according to petrological studies, records fluxing of a deep-derived CO2-rich fluid in the deep to shallow-level crustal magmatic systems. Assuming that this fluid fluxing is the process of volcanic CO2 emission, we quantified the fluxes of CO2 by combining a fluid transport model with melt inclusion data. We formulated CO2 fluxing as an advective fluid flow in a basaltic magma column with exchanging volatiles, and applied it to the melt inclusion data from Mount Etna, the type locality of a CO2-emitting volcano. The flux of CO2 was calculated to be 2.4-6.0kt/day, which is consistent with the observed volcanic CO2 emission rate of 1-10kt/day. We propose that this method potentially provides a means to quantify CO2 emission rates in past volcanic activities. Because CO2 fluxing is an open-system process, the estimated CO2 emission over geological timescales evaluated with this method should give much higher values than evaluations based simply on the volume of the erupted magmas. © 2012 Elsevier B.V.
Kawamura S.,Muroran Institute of Technology |
Miura S.,Hokkaido University
Soils and Foundations | Year: 2013
Rainfall- and earthquake-induced failures of slopes formed by volcanic soils occur frequently in Hokkaido, Japan. The aim of this study is to clarify the failure mechanisms of volcanic slopes caused by both rainfall and freeze-thaw action in cold regions such as Hokkaido. Using model slopes of different shapes formed by volcanic soils, a series of rainfall tests are conducted under field conditions in which a spray nozzle is used to simulate rainfall intensity. Test results show that the surface failure of volcanic slopes differs depending strongly on the angle and the initial moisture content of the slopes. Based on the results of the model testing, the effects of freezing and thawing on the failure mechanism are drawn upon to propose an evaluation method for slope stability. In consideration of the model test results, it is found that the formation of a frozen layer and the softening of the slope surface, due to the freeze-thaw action, are significant for the stability of volcanic slopes in cold regions, and that slope failure can be uniquely assessed by the changes in water content in zones subjected to rainfall and freeze-thaw action. © 2013 The Japanese Geotechnical Society. Production and hosting by Elsevier B.V. All rights reserved.
Sato T.,Hokkaido University
Monthly Weather Review | Year: 2013
Mesoscale processes that cause tremendous amounts of precipitation around the Meghalaya Plateau, northeast India, were investigated using a regional atmospheric model, with a particular focus on the possible role of an intraseasonal oscillation (ISO) and the diurnal cycle. A numerical experiment was conducted using the Weather Research and Forecasting Model (WRF) to simulate a prominent submonthly-scale ISO event observed during June-July 2004. A WRF experiment successfully simulated the timing and magnitude of precipitation during the first active period and subsequent inactive period of the ISO, despite large biases in the second active period. The WRF experiment revealed that the magnitude of prevailing southwesterly winds in the lower troposphere differs significantly between active and inactive periods; strong southwesterly flow transports abundant moisture to the southern slope of the Meghalaya Plateau during the active period, which triggers forced lifting and brings orographic precipitation. However, low-level wind during the inactive period is too weak to overcome the vertical stratification barrier; hence, it is unable to reach the condensation level. The WRF experiment suggested that the diurnal cycle of precipitation is enhanced during the active period, exhibiting an evening to early morning maximum, as observed by the Tropical Rainfall Measuring Mission (TRMM). The experiment also indicated a prominent nocturnal low-level jet (LLJ) appearing at 900 hPa. The direction of the LLJ varies clockwise with time, which accelerates the preexisting southwesterly flow during 1800-0600 LT. The diurnal variation of the LLJ is responsible for the evening to early morning maximum of precipitation, thus contributing to the precipitation variability in the ISO. © 2013 American Meteorological Society.
Oku K.,Hokkaido University
Rheumatology (Oxford, England) | Year: 2013
The aim of this study was to investigate the effects of phosphatidylserine-dependent antiprothrombin antibody (aPS/PT) on the expression of tissue factor (TF) and the signal transduction pathway in procoagulant cells. Peripheral blood mononuclear cells (PBMCs) from a healthy donor, murine monocyte RAW264.7 cells and human umbilical vein endothelial cells (HUVECs) were treated with either IgG fractions obtained from APS patients who were positive for aPS/PT or a murine monoclonal aPS/PT antibody, 231D, in the presence of prothrombin. The levels of TF mRNA were measured using real-time PCR. TF function, as measured by procoagulant activity, was determined with a clotting assay. 231D binding on the surface of treated cells was determined by flow cytometric analysis. Screening for phosphorylation of intracellular signalling proteins was conducted using an array assay. Phosphorylation of p38 MAPK was quantitatively analysed with ELISA, and SB203580 was used as a specific inhibitor of p38 MAPK. Specific siRNA for p38 MAPK was used for the knockdown assay. The IgG fractions from APS patients and 231D induced TF mRNA overexpression and shortening of coagulation time in cells in the presence of prothrombin. The 231D moiety induced phosphorylation of p38 MAPK after binding to the cell surface of RAW264.7 cells. SB203580 or p38 siRNA significantly hampered TF overexpression. Expression of TF in procoagulant cells was induced by aPS/PT via p38MAPK phosphorylation. This phenomenon may be correlated with the thrombogenicity of APS.
Tachikawa H.,Hokkaido University
RSC Advances | Year: 2012
The ionization dynamics of a benzene dimer have been investigated by means of a direct ab initio molecular dynamics (MD) method in order to elucidate the reaction mechanism. Following the ionization, the T-shaped neutral benzene dimer was gradually changed to a π-stacked benzene dimer cation. The structural change and time evolution of the electronic absorption spectrum were completely visualized for the first time. The time scale of the dimer formation was estimated to be 1.0-1.5 ps. First, the benzene molecule at the stem position (Bz′) was ionized, and the structure of Bz′+ was rapidly deformed due to the Jahn-Teller effects. Next, the rotation of (Bz′) + gradually occurred relative to Bz. Finally, a π-stacked benzene dimer cation was formed. TD-DFT calculations indicated that the absorption spectrum of (Bz)2 + is blue-shifted as a function of time. The formation mechanism of the benzene dimer cation was discussed on the basis of the theoretical results. © 2012 The Royal Society of Chemistry.
Ueda W.,Hokkaido University
Journal of the Japan Petroleum Institute | Year: 2013
Solid-state metal oxides with three-dimensional organization of catalytic components at nano-scale have high potential as catalysts for chemical conversion because the materials could provide unique reaction fields at catalytic active sites which are particularly important for multi-step catalytic reactions like selective oxidation. Here, crystalline Mo3VOx, a new type complex metal oxide catalyst, is introduced as a prominent example of solid-state metal oxides with three-dimensional organization. The material has a network arrangement of pentagonal units as a structure building block with the formation of 6-member ring channel and 7-member ring channel in its crystal structure. The material showed an outstanding catalytic performance for both selective oxidations of ethane to ethene and of acrolein to acrylic acid, revealing the importance of these structures for the catalytic oxidation activity. The outstanding catalytic performance for the reactions is ascribed to octahedra clusters isolated in the pentagonal unit network and to microporous property of the 7-member ring channel.
Yamagishi M.,Hokkaido University
Scientia Horticulturae | Year: 2013
Flower colour and pigmentation patterning are key traits for floricultural crops. Large variation in tepal colours is observed among lily cultivars, including pink, red, yellow, orange, and white. In addition, large variation in the patterning of these colours are found in lily flowers, including raised spots, splatter spots, and bicolours, which are caused by spatially and temporally discrete anthocyanin deposition. Many Oriental and Asiatic hybrid lily cultivars accumulate pigments such as anthocyanins, whose biosynthesis is co-ordinately regulated by R2R3-MYB and basic helix-loop-helix transcription factors. Lilies have several R2R3-MYB genes regulating anthocyanin biosynthesis, which are key determinants of pigmentation intensity and patterning in flowers. Additional pigments include xanthophylls and capsanthin (carotenoids), which accumulate in yellow and orange lily flowers, respectively. Biosynthesis and cleavage of carotenoids should be important factors that determine carotenoid accumulation. Therefore, this review article discusses the molecular determination of flower colouring, colour intensity, and the mechanisms involved in the pigmentation patterning of lily flowers. © 2013 Elsevier B.V.
Nakamura H.,Kagoshima University |
Nishina A.,Kagoshima University |
Minobe S.,Hokkaido University
Journal of Climate | Year: 2012
A large meridional shift of the sea surface temperature front occurs off the south coast of Japan associated with transitions between the large-meander and straight paths of the Kuroshio. Most extratropical cyclones generated in winter near the Kuroshio in the East China Sea pass through the region where the Kuroshio takes either the meander or the straight path. To examine whether such cyclones change their tracks and intensities according to the two states of the path, a new dataset of winter cyclone tracks derived from surface weather charts from the period 1969/70-2008/09 was produced. The composite analysis of cyclone tracks with respect to the meander and straight path states reveals the following: the cyclone track axis for the meander path state is located away from the south coast of Japan with a dispersive tendency, while that for the straight path state is attached to the south coast with a long extending feature. A difference in track between these two states also occurs to the east of Japan over the North Pacific. In addition, this behavior of the cyclone track is shown to be independent of the wintertime atmospheric circulation anomalies around Japan. The development rate of cyclones is 41% faster for the straight path state than the meander path state. Snowfall in Tokyo caused by south-coast cyclones is more frequent for the meander than the straight path state because the former state can act to decrease air temperature in Tokyo. © 2012 American Meteorological Society.
Harada J.,Hokkaido University |
Ogawa K.,University of Tokyo
Crystal Growth and Design | Year: 2014
The crystal structures of several (E)-stilbenes and 1,2-diarylethane that have methyl or chloro substituents were examined by variable-temperature X-ray diffraction analysis. All the compounds showed disorders in their crystal structures at least at room temperature. In the crystal structures of the molecules with ortho-methyl groups, the disorder observed at room temperature disappeared at 90 K. The dynamic disorders in these crystals were explained in terms of the conformational changes induced by pedal motions, which were not obstructed by the ortho-methyl groups. In the crystals of the stilbenes with α-substituents, however, the populations of the two disordered conformers did not change with temperature, which indicates that the disorders were static and these molecules did not undergo the pedal motions in their crystals. Theoretical calculations on the energy barriers for the pedal motions indicated that the observed restriction of the pedal motion in crystals was originated not only in the intramolecular steric repulsions involving the α-substituents but mainly in the steric repulsions between the α-substituents and the surrounding molecules in the crystals. The pedal motion can proceed only when the shapes of the molecules do not largely change during the process. © 2014 American Chemical Society.
Inagaki M.,Hokkaido University |
Ohta N.,Toyo Tanso |
Hishiyama Y.,Tokyo City University
Carbon | Year: 2013
Aromatic polyimides are often employed as carbon precursors to prepare in various morphologies. After a brief explanation on carbonization behavior of aromatic polyimides, structure and functionalities of carbon materials prepared from polyimides are reviewed; highly-crystalline graphite membranes, nanoporous carbon membranes, carbon foams, carbon nanofibers and carbon nanoparticles. The advantages of polyimides as carbon precursors are discussed. © 2013 Elsevier Ltd. All rights reserved.
Yabushita A.,Kyoto University |
Hama T.,Hokkaido University |
Journal of Photochemistry and Photobiology C: Photochemistry Reviews | Year: 2013
The photoprocesses of water ice play an important role in regions of interstellar space, such as interstellar clouds and outer solar systems. Vacuum-ultraviolet absorption of water ice leads to dissociation of water molecules, and allows subsequent reactions of photoproducts on/in ice. There have been many laboratory studies that identify photoproducts and estimate product yields, reaction mechanisms and energy partitioning in the reaction products. Among them, the experimental approaches aimed at understanding the photoprocesses on the water ice surface can give new insight into the chemical reaction network in interstellar space. In this review, we focus on photochemical processes of water ice relevant to surface astrochemistry following vacuum-ultraviolet photolysis of water ice at a low temperature from a surface reaction dynamics' point of view. © 2013 Elsevier B.V.
Tachikawa H.,Hokkaido University
RSC Advances | Year: 2012
Direct ab initio molecular dynamics (MD) has been applied to the electron detachment dynamics of Cu-(H2O)n (n = 1-3). The initial structures of Cu(H2O)n were generated randomly around the equilibrium point of anionic complex Cu-(H 2O)n and then trajectories were run from the vertical electron detachment points of Cu-(H2O)n. It was found that three reaction channels compete with each other when n = 1: dissociation channel (the product is Cu + H2O) and complex formation channel (the product is neutral CuH2O complex). The complex channel is further classified to two kind of complexes: a strongly bound (I) complex and a weakly bound (II) complex. The dissociation channel occurred from an inner Franck-Condon (FC) region where the distance Cu--H2O is shorter than the equilibrium point. On the other hand, the complex formation channel occurred from the wide FC region. In case of n = 2 and 3, dissociation channels were the main products. The mechanism of the electron detachment dynamics was discussed on the basis of the theoretical results. © 2012 The Royal Society of Chemistry.
Saitoh K.,Hokkaido University |
Matsuo S.,Fujikura Ltd
Nanophotonics | Year: 2013
We experience Internet traffic growth of 100 times every 10 years. However, the capacity of existing standard single-mode fiber is approaching its fundamental limit regardless of significant realization of transmission technologies which allow for high spectral efficiencies. Space division multiplexing (SDM) based on multicore fibers (MCFs) has emerged as a solution to the problem of saturation of the capacity of optical transmission systems. This article presents the recent progress on the MCFs for future large capacity long-distance transmission systems. In MCFs, there is a tradeoff relationship between low crosstalk and high multiplicity, therefore the maximum number of cores and the core arrangement have to be carefully determined based on the required crosstalk level and core size. The state-of-the-art of fabricated MCFs and the transmission experiments using MCFs are reviewed. The current maximum capacity-distance product in MCF transmission is 368.2 (184.1+184.1) Pb/s/fiber km with the relative spatial efficiency of 4.7 compared with a standard single-mode fiber. In order to increase the spatial efficiency as well as the capacity-distance product further in MCFs, the possibility of heterogeneous MCFs and few-mode MCFs is also presented. © 2013 Science Wise Publishing & DE GRUYTER.
Ohtani B.,Hokkaido University
Catalysts | Year: 2013
This short review paper shows the significance of recombination of a photoexcited electron and a hole in conduction and valence bands, respectively, of a titania photocatalyst, since recombination has not yet been fully understood and has not been evaluated adequately during the past several decades of research on heterogeneous photocatalysis. © 2013 by the authors; licensee MDPI, Basel, Switzerland.
Ebuchi N.,Hokkaido University
IEEE Transactions on Geoscience and Remote Sensing | Year: 2012
Marine surface wind vectors observed by the Advanced Scatterometer on the MetOp-A satellite are evaluated by assessing their self-consistency. Global statistics on wind speeds and directions were calculated from the data for a period of one year. The wind speed histograms exhibited a clear dependence on the cross-track wind vector cell (WVC) location, which corresponds to the incidence angle. This trend was reflected in the higher order statistics (standard deviation, skewness, and kurtosis) of the wind speed distribution. The histograms of the wind directions relative to the satellite flight direction clearly showed systematic errors relative to the antenna beam directions. The number density of the wind directions exhibited a systematic pattern relative to the antenna beam directions, and the pattern varied with wind speed and cross-track WVC location. These systematic errors in the wind speed and direction may affect the divergence/convergence and rotation of the wind field. The results of this study suggest the need for further refinements of the wind retrieval algorithms and the C-band geophysical model function. It was also confirmed that the evaluation technique based on the statistical distributions of scatterometer-derived vector winds is effective for identifying systematic errors in the wind speeds and directions. © 2012 IEEE.
Kusahara K.,University of Tokyo |
Kusahara K.,Hokkaido University |
Hasumi H.,University of Tokyo
Journal of Geophysical Research: Oceans | Year: 2013
We investigate basal melting of all Antarctic ice shelves by a circumpolar ice shelf-sea ice-ocean coupled model and estimate the total basal melting of 770-944 Gt/yr under present-day climate conditions. We present a comparison of the basal melting with previous observational and modeling estimates for each ice shelf. Heat sources for basal melting are largely different among the ice shelves. Sensitivities of the basal melting to surface air warming and to enhanced westerly winds over the Antarctic Circumpolar Current are investigated from a series of numerical experiments. In this model the total basal melting strongly depends on the surface air warming but is hardly affected by the change of westerly winds. The magnitude of the basal melting response to the warming varies widely from one ice shelf to another. The largest response is found at ice shelves in the Bellingshausen Sea, followed by those in the Eastern Weddell Sea and the Indian sector. These increases of basal melting are caused by increases of Circumpolar Deep Water and/or Antarctic Surface Water into ice shelf cavities. By contrast, basal melting of ice shelves in the Ross and Weddell Seas is insensitive to the surface air warming, because even in the warming experiments there is high sea ice production at the front of the ice shelves that keeps the water temperature to the surface freezing point. Weakening of the thermohaline circulation driven by Antarctic dense water formation under warming climate conditions is enhanced by basal melting of ice shelves. ©2013. American Geophysical Union. All Rights Reserved.
Izumi K.,University of Tokyo |
Miyaji T.,Hokkaido University |
Tanabe K.,University of Tokyo
Palaeogeography, Palaeoclimatology, Palaeoecology | Year: 2012
The early Toarcian oceanic anoxic event (T-OAE) was marked by the worldwide burial of organic-rich black shales and a coincident pronounced negative carbon-isotope excursion of carbonates, organic matter, and fossil wood. This characteristic carbon-isotope perturbation and other geochemical records have been recognized in many sections in the European domain and in selected sections in the central and eastern Panthalassa, but not in the western Panthalassa. We present herein, for the first time, data of carbon isotope ratios of organic carbon, total organic carbon (TOC) contents, and sedimentary fabrics from the uppermost Pliensbachian to the lower Toarcian sequence in the Sakuraguchi-dani Valley, Toyora area, west Japan, that was deposited in the shelf basin of the northwestern Panthalassa. The carbon-isotope profile displays a similar trend to those in contemporaneous strata in the Tethys and in the eastern and central Panthalassic regions, which is characterized by a distinct negative excursion around the Tenuicostatum/Falciferum Zone boundary in the early Toarcian. This evidence suggests that the widely recognized negative carbon-isotope excursion represents a nature of the global carbon-cycle perturbation. Analyses of total organic carbon contents and sedimentary fabrics in the study section reveal that accumulation of organic carbon occurred and anoxic bottom-water was prevalent during the early Toarcian. The most organic-rich strata and bottom-water anoxia described in the study section, however, exist in the interval showing the carbon-isotope positive recovery after the abrupt negative shift, and this fact suggests that the accumulation of organic matters and development of marine anoxia were globally diachronous, even though the negative CIE was interpreted as a synchronous event. Our study also demonstrates that the early Toarcian anoxia in the northwestern Panthalassic basin was not a single and continuous anoxic event but was interrupted by episodic short-term oxygenation events. © 2011 Elsevier B.V.
Nihashi S.,Tomakomai National College of Technology |
Ohshima K.I.,Hokkaido University |
Kimura N.,University of Tokyo
Journal of Climate | Year: 2012
Sea ice formation, its transport, and its melting cause the redistribution of heat and salt, which plays an important role in the climate and biogeochemical systems. In the Sea of Okhotsk, a heat and salt flux dataset is created in which such sea ice processes are included, with a spatial resolution of;12.5 km. The dataset is based on a heat budget analysis using ice concentration, thickness, and drift speed from satellite observations and the ECMWFInterimRe-Analysis (ERA-Interim) data. The salt flux calculation considers both salt supplied to the ocean from sea ice production and freshwater supplied when the icemelts. This dataset will be useful for the validation and boundary conditions of modeling studies. The spatial distribution of the annual fluxes shows a distinct contrast between north and south: significant ocean cooling with salt supply is shown in the northern coastal polynya region, while ocean heating with freshwater supply is shown in the south. This contrast suggests a transport of freshwater and negative heat by ice advection. The annual fluxes also show ocean cooling with freshwater supply in the Kashevarov Bank (KB) region and the central and eastern Sea ofOkhotsk, suggesting the effect of warm water advection. In the ice melt season, relatively prominent ice melting is shown in the coastal polynya region, probably due to large solar heating of the upper ocean. This indicates that the polynya works as a "meltwater factory" in spring, contrasting with its role as an "ice factory" in winter. In the coastal polynya region, the spatial distribution of phytoplankton bloom roughly corresponds with the ice melt region. © 2012 American Meteorological Society.
Ogiso M.,Sapporo District Meteorological Observatory |
Yomogida K.,Hokkaido University
Journal of Volcanology and Geothermal Research | Year: 2012
We estimate the locations of three tremor sequences, denoted A, B, and C, that occurred before the 2008 eruption at Meakandake volcano, eastern Hokkaido, Japan, using the spatial distribution of seismic amplitudes of volcanic tremor. Although we used only five seismic stations, we could estimate the locations of three tremor sequences. We find two different tremor source areas: those of Tremor A located about 2. km southwest of the erupted crater (Area A) and the other about 1. km southeast to south of the crater as that of the Tremor C (Area B). The location of an early phase of the Tremor B is estimated in Area A while the location of its later phase appears to connect the two areas. This location migration during Tremor B occurred simultaneously with other important geophysical phenomena before the eruption event, as suggested by geodetic and geomagnetic studies. Our findings of the two tremor locations of the tremor sequences and location migration during Tremor B may be important for future monitoring activities at Meakandake volcano, particularly to forecast the location of a possible phreatic eruption. © 2011 Elsevier B.V.
Tachikawa H.,Hokkaido University
Journal of Physical Chemistry A | Year: 2014
Ionization dynamics of water microsolvated sulfur dioxide SO 2(H2O)n (n = 1-3 and 6) have been investigated by means of direct ab initio molecular dynamics (AIMD) method to elucidate the hydration effects of OH addition reaction to SO2 following the ionization. The calculations showed that the neutral 1:1 complex SO 2-H2O has a Cs symmetry and the sulfur of SO2 interacts with the oxygen of H2O with an eclipsed form. In the case of ionization of SO2-H2O 1:1 complex (n = 1), the cation complex composed of [H2O-SO2]+ with a face-to-face form was obtained as the product. The OH addition reactions to SO2 were found in larger systems (n = 2, 3, and 6) following the ionization. The reaction was expressed as SO2 +(H 2O)n → SO2(OH) ···H+(H2O)n-1 (n = 2, 3, and 6). The proton generated as (SO2-H2O)+ → (HSO3) + H+ was stabilized by the second water molecule as the reaction: H+ + H2O → H 3O+. These processes occurred and were completed within the cluster. The OH addition mechanism in SO2 +(H 2O)n cluster was discussed on the basis of the present results. © 2014 American Chemical Society.
Kwon H.J.,Hokkaido University
Journal of Endocrinology | Year: 2012
Prechondrogenic condensation is the most critical process in skeletal patterning. A previous study demonstrated that ATP oscillations driven by CA2+ oscillations play a critical role in prechondrogenic condensation by inducing oscillatory secretion. However, it remains unknown what mechanisms initiate the CA2+-driven ATP oscillations, mediate the link between CA2+ and ATP oscillations, and then result in oscillatory secretion in chondrogenesis. This study has shown that extracellular ATP signaling was required for both ATP oscillations and prechondrogenic condensation. Among P2 receptors, the P2X4 receptor revealed the strongest expression level and mediated ATP oscillations in chondrogenesis. Moreover, blockage of P2X4 activity abrogated not only chondrogenic differentiation but also prechondrogenic condensation. In addition, both ATP oscillations and secretion activity depended on cAMP/PKA signaling but not on KATP channel activity and PKC or PKG signaling. This study proposes that CA2+-driven ATP oscillations essential for prechondrogenic condensation is initiated by extracellularATP signaling via P2X4 receptor and ismediated by cAMP/PKA signaling and that cAMP/PKA signaling induces oscillatory secretion to underlie prechondrogenic condensation, in cooperation with CA2+ and ATP oscillations. © 2012 Society for Endocrinology.
Chen C.,Hokkaido University
Journal of Neurophysiology | Year: 2015
Our understanding of the neural basis of reinforcement learning and intelligence, two key factors contributing to human strivings, has progressed significantly recently. However, the overlap of these two lines of research, namely, how intelligence affects neural responses during reinforcement learning, remains uninvestigated. A mini-review of three existing studies suggests that higher IQ (especially fluid IQ) may enhance the neural signal of positive prediction error in dorsolateral prefrontal cortex, dorsal anterior cingulate cortex, and striatum, several brain substrates of reinforcement learning or intelligence. © 2015 the American Physiological Society.
Sassa T.,Hokkaido University
Journal of Neurogenetics | Year: 2013
One of the most fascinating questions in evolutionary biology is how traits unique to humans, such as their high cognitive abilities, erect bipedalism, and hairless skin, are encoded in the genome. Recent advances in genomics have begun to reveal differences between the genomes of the great apes. It has become evident that one of the many mutation types, segmental duplication, has drastically increased in the primate genomes, and most remarkably in the human genome. Genes contained in these segmental duplications have a tremendous potential to cause genetic innovation, probably accounting for the acquisition of human-specific traits. In this review, I begin with an overview of the genes, which have increased their copy number specifically in the human lineage, following its separation from the common ancestor with our closest living relative, the chimpanzee. Then, I introduce the recent experimental approaches, focusing on SRGAP2, which has been partially duplicated, to elucidate the role of SRGAP2 protein and its human-specific paralogs in human brain development and evolution. © 2013 Informa Healthcare USA, Inc.
Ikeda M.,Hokkaido University
Polar Research | Year: 2012
Arctic Ocean sea ice has been diminishing since 1970, as shown by National Snow and Ice Data Center data. In addition to decadal variability, low ice anomalies in the Pacific-Siberian region have been occurring at shorter timescales. The influence of the widely-known Northern Annular Mode (NAM) occurs across all seasons. In this study, empirical orthogonal function (EOF) analysis was applied to sea-level pressure in National Centers for Environmental Prediction Reanalysis data for 1960-2007, showing the NAM to be the leading mode of variability and the Arctic Dipole Mode (ADM) to be the second leading mode. The ADM changes markedly across seasons. In autumn- winter, it has a pole over Siberia and a pole over Greenland, at opposite signs at a several-year scale, whereas the spring-summer ADM (ADMSS) has a pole over Europe and a pole over Canada. In the 1980s, the most influential mode shifted from the NAM to the ADM, when the Pacific sector had low ice cover at a 1-year lag from the positive ADM, which was marked by low pressure over Siberia. In years when the ADMSS was pronounced, it was responsible for distinct ice variability over the East Siberian-Laptev seas. The frequency separation in this study identified the contributions of the ADM and ADMSS. Effects of the latter are difficult to predict since it is intermittent and changes its sign biennially. The ADM and ADMSS should be closely watched in relation to the ongoing ice reduction in the Pacific-Siberian region. © 2012 M. Ikeda.
Koper M.T.M.,Leiden University |
Koper M.T.M.,Hokkaido University
Chemical Science | Year: 2013
This perspective article outlines a simple but general theoretical analysis for multiple proton-electron transfer reactions, based on the microscopic theory of proton-coupled electron transfer reactions, recent developments in the thermodynamic theory of multi-step electron transfer reactions, and the experimental realization that many multiple proton-coupled electron transfer reactions feature decoupled proton-electron steps in their mechanism. It is shown that decoupling of proton and electron transfer leads to a strong pH dependence of the overall catalytic reaction, implying an optimal pH for high catalytic turnover, and an associated optimal catalyst at the optimal pH. When more than one catalytic intermediate is involved, scaling relationships between intermediates may dictate the optimal catalyst and limit the extent of reversibility that may be achievable for a multiple proton-electron transfer reaction. The theory is discussed in relation to the experimental results for a number of redox reactions that are of importance for sustainable energy conversion, primarily focusing on their pH dependence. © 2013 The Royal Society of Chemistry.
Fujinuma J.,Hokkaido University |
Harrison R.D.,CAS Xishuangbanna Tropical Botanical Garden
PLoS ONE | Year: 2012
Edge-effects greatly extend the area of tropical forests degraded through human activities. At Pasoh, Peninsular Malaysia, it has been suggested that soil disturbance by highly abundant wild pigs (Sus scrofa), which feed in adjacent Oil Palm plantations, may have mediated the invasion of Clidemia hirta (Melastomataceae) into the diverse tropical lowland rain forest. To investigate this hypothesis, we established three 1 km transects from the forest/Oil Palm plantation boundary into the forest interior. We recorded the distribution of soil disturbance by wild pigs, C. hirta abundance, and environmental variables. These data were analyzed using a hierarchical Bayesian model that incorporated spatial auto-correlation in the environmental variables. As predicted, soil disturbance by wild pigs declined with distance from forest edge and C. hirta abundance was correlated with the level of soil disturbance. Importantly there was no effect of distance on C. hirta abundance, after controlling for the effect of soil disturbance. Clidemia hirta abundance was also correlated with the presence of canopy openings, but there was no significant association between the occurrence of canopy openings and distance from the edge. Increased levels of soil disturbance and C. hirta abundance were still detectable approximately 1 km from the edge, demonstrating the potential for exceptionally large-scale animal mediated edge effects. © 2012 Fujinuma, Harrison.
Ihara Y.,Doshisha University |
Morishima-Kawashima M.,Hokkaido University |
Nixon R.,Nathan Kline Institute |
Nixon R.,New York University
Cold Spring Harbor Perspectives in Medicine | Year: 2012
As neurons age, their survival depends on eliminating a growing burden of damaged, potentially toxic proteins and organelles-a capability that declines owing to aging and disease factors. Here, we review the two proteolytic systems principally responsible for protein quality control in neurons and their important contributions to Alzheimer disease pathogenesis. In the first section, the discovery of paired helical filament ubiquitination is described as a backdrop for discussing the importance of the ubiquitin-proteasome system in Alzheimer disease. In the second section, we review the prominent involvement of the lysosomal system beginning with pathological endosomal-lysosomal activation and signaling at the very earliest stages of Alzheimer disease followed by the progressive failure of autophagy. These abnormalities, which result in part from Alzheimer-related genes acting directly on these lysosomal pathways, contribute to the development of each of the Alzheimer neuropathological hallmarks and represent a promising therapeutic target. © 2012 Cold Spring Harbor Laboratory Press all rights reserved.
Abe R.,Hokkaido University
Journal of Dermatology | Year: 2015
Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are life-threatening cutaneous adverse drug reactions that induce widespread epidermal necrosis. Recent advances in pharmacogenomic studies have provided evidence of genetic predispositions to SJS/TEN. Several concepts have been proposed to explain the pathogenesis of severe cutaneous adverse drug reactions. In the hapten concept, small molecules called haptens elicit an immune response only when attached to proteins. The "p-i" concept postulates that the causative drugs can stimulate cells by binding directly and reversibly to immune receptors. In addition, there is the idea that drugs alter the antigen by binding to the human leukocyte antigen pocket. With regard to keratinocyte death, several cell death mediators, such as FasL, granulysin and annexin A1, have been proposed as playing a role in SJS/TEN pathogenesis. A subset of T lymphocytes, including regulatory T cells, also may play a role in SJS/TEN. © 2014 Japanese Dermatological Association.
Oba T.,2 2 3 Sendagaya |
Irino T.,Hokkaido University
Journal of Quaternary Science | Year: 2012
The Japan Sea is connected with the Okhotsk Sea and Northwest Pacific through three straits, viz. Mamiya (Tartarskiy), Soya and Tsugaru, and with the East China Sea through Tsushima Strait, all having sill depths of <140m. Therefore, the Japan Sea was almost isolated from the surrounding seas during the Last Glacial Maximum (LGM; ca. 20ka). As a result of nearly broken communication with the surrounding seas and strengthened surface stratification due to locked fresh water in the basin during the LGM, it became an anoxic basin. This major shift in the surface water properties of the basin left its imprint in the oxygen isotopic composition (δ18OPF) of the planktonic foraminifera. The δ18OPF exhibits extremely low values (∼0.5‰ vs. Belemnite from Pedee formation, South Carolina: PDB) during the last two glacial maxima, ca. 20ka (Marine Isotope Stage (MIS) 2.2) and ca. 140ka (MIS 6.2). These decreases are in contrast to the expected generally high glacial values of >3‰ recorded in the MIS 3-4 sections of the studied cores. This observation indicates nearly similar surface water conditions in the Japan Sea during both the previous glacial maxima, and hence suggests negligible effect of strait tectonics on the sea level since the last 140ka. Low δ18OPF values with small amplitude are also observed at the cold stage MIS 6.4, but not observed at another cold stage MIS 4.2. This observation suggests that the low-salinity surface water in the Japan Sea started to develop at the sea level between MIS 4.2 and 6.4. Judging from the cross-section of the Tsushima Strait and the sea floor topography of the East China Sea, the sea level between MIS 4.2 and 6.4 must have been between 90m and 100m below the present. From a proportional relationship between the standard δ18O curve (LR04) in deep-sea cores and globally averaged sea-level change, the eustatic sea level obtained for the LGM is 120±7m below the present. Thus the Japan Sea, in a far-field location from the continental ice sheets, provides an important clue for estimation of the eustatic sea level at the LGM. © 2012 John Wiley & Sons, Ltd.
Ikeda T.,Hokkaido University
Journal of Oceanography | Year: 2012
Respiration (=oxygen consumption) rates of 28 zooplankton species belonging to 10 taxa from 500 to 5,000 m depth of the western subarctic Pacific Ocean were determined as 0. 027-0. 44 μLO 2 mg dry mass -1 h -1 at in situ temperatures (1. 5-3 °C), which are 80 % lower than the rates of the epipelagic Antarctic zooplankton with similar body mass and at a comparable temperature. In terms of adjusted metabolic rate to 1 mg body N (AMR; μLO 2 mg N -0. 8 h -1) at 1 °C, the present results (mean 1. 66) fall well within the range (0. 84-3. 32) reported for copepods, chaetognaths, and mixed crustaceans from 500 to 7,000 m in the subarctic Pacific Ocean and Antarctic waters. Judging from their body C:N elemental ratios and ash-free dry mass (=organic matter) data, the major component of organic matter is deduced to be protein (C:N = 3. 4-8. 1, by mass) for 19 out of 28 species and lipids (C:N = 8. 6-13. 0) for the remaining 9 species. © 2012 The Oceanographic Society of Japan and Springer.
Horinouchi T.,Hokkaido University
Journal of the Atmospheric Sciences | Year: 2012
Aquaplanet simulations for a given sea surface temperature (SST) are conducted to elucidate possible roles of transient variability in the Hadley circulation and the intertropical convergence zone (ITCZ). Their roles are best illustrated with globally uniform SSTs. For such SSTs, an ITCZ and a Hadley circulation that are nearly equatorially symmetric emerge spontaneously. Their strength varies over a wide range from being faint to climatologically significant depending on a tunable parameter of the model's cumulus parameterization. In some cases asymmetric Hadley circulations formed along with long-lived tropical cyclones. The tunable parameter affects the transient variability of tropical precipitation. In the runs in which well-defined near-symmetric ITCZs formed, tropical precipitation exhibited clear signatures of convectively coupled equatorial waves. The waves can explain the concentration of precipitation to the equatorial region, which induces the Hadley circulation. Also, the meridional structures of simulated ITCZs are consistent with the distribution of convergence/divergence associated with dominant equatorial wave modes. Even when the pole-equator temperature gradient is introduced, the dependence of the strength of the circulation to transient disturbances remains. Therefore, transient variability may have a broader impact on tropical climate and its numerical modeling than has been thought. The reason that a wide variety of circulation is possible when the SST gradient is weak is because the distribution of latent heating can be interactively adjusted while a circulation is formed. Angular momentum budget does not provide an effective thermodynamic constraint, since baroclinic instability redistributes the angular momentum. © 2012 American Meteorological Society.
Mizuta G.,Hokkaido University
Journal of Physical Oceanography | Year: 2012
To investigate the effect of the Rossby waves on an eastward jet such as the Kuroshio or Gulf Stream Extensions, a series of numerical experiments is conducted using a primitive equation model. In these experiments, an inflow and an outflow imposed on the western and eastern boundaries drive an unstable narrow jet and a broad interior flow in the western and eastern regions of the model domain, respectively. The barotropic Rossby waves are radiated from the transient region between the two regions. The eddy potential vorticity flux by the waves tends to compensate for the difference in the mean potential vorticity along mean streamlines between both sides of the transient region. Instability of the jet is insufficient for this compensation and weakens the mean potential vorticity gradient too much. Moreover, as the potential vorticity of the outflow is increased, the Rossby waves are intensified in order to compensate for the increase in the difference in the mean potential vorticity. These features strongly suggest that the Rossby waves are substantial in matching a jet with an interior flow. The speed of the waves and properties of eddies in recirculations of the jet are consistent with a two-layer analytic model, which indicates that the Rossby waves are radiated from eddies in recirculations. These eddies as well as the Rossby waves increase in amplitude with the transport of the recirculation near the surface presumably because of mean advection. Therefore, the mean potential vorticity of the interior flow, the intensity of the Rossby waves, and the transport of the recirculation change consistently with one another. © 2012 American Meteorological Society.
Utsumi S.,Hokkaido University
Ecological Research | Year: 2013
In the 21st century, researchers have attempted a synthesis between community ecology and evolutionary biology. This emerging research area, which aims to synthesize community ecology and evolutionary biology, is evolutionary community ecology. Evolutionary community ecology addresses how intraspecific trait variation in community members is essential for predicting community properties and, how community properties are a key component of the selective forces that determine genetic and phenotypic variation in a community member. In this paper, I review recent findings in evolutionary community ecology in plant-associated arthropods in terrestrial ecosystems. I discuss roles of both genetic variation and phenotypic plasticity as a source of trait variation in plants in shaping plant-associated arthropod communities. Also, I discuss effects of genetic variation in herbivores on plant-associated arthropod communities. Furthermore, I highlight community context evolution in which multiple species interactions and community composition affect trait evolution of a community member. Finally, I argue that future studies should investigate a feedback loop between community and evolutionary dynamics beyond unidirectional studies on effects of evolution on a community or vice versa. This approach will provide major insights into mechanistic principles for making predictions of community ecology. © 2013 The Ecological Society of Japan.
Sakajo T.,Hokkaido University
Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences | Year: 2012
A two-dimensional potential flow in an unbounded domain with two parallel plates is considered. We examine whether two free point vortices can be trapped near the two plates in the presence of a uniform flow and observe whether these stationary point vortices enhance the force on the plates. The present study is an extension of previously published work in which a free point vortex over a single plate is investigated. The flow problem is motivated by an airfoil design problem for the double wings. Moreover, it also contributes to a design problem for an efficient wind turbine with vertical blades. In order to obtain the point-vortex equilibria numerically, we make use of a linear algebraic algorithm combined with a stochastic process, called the Brownian ratchet scheme. The ratchet scheme allows us to capture a family of stationary point vortices in multiply connected domains with ease. As a result, we find that stationary point vortices exist around the two plates and they enhance the downward force and the counter-clockwise rotational force acting on the two plates. © 2011 The Royal Society.
Asaka M.,Hokkaido University
Nihon rinsho. Japanese journal of clinical medicine | Year: 2012
Gastric cancer screening by simultaneous measurement of serum pepsinogen and H. pylori antibody combined with eradication of H. pylori in all individuals at risk would initially increase national healthcare expenditure, but would eventually archive great savings by markedly reducing the cost of treating gastric cancer. The proposed strategy would prevent about 150,000 deaths from gastric cancer during the 5 years after its adoption. If the loss caused by these deaths is also taken into account, the economic effect of this strategy becomes enormous. It would probably reduce the incidence of gastric cancer by more than 80-90% within 10 years. The Japanese government should take the initiative to implement this strategy as soon as possible.
Takeuchi T.,Kochi Medical School |
Adachi Y.,Hokkaido University |
Nagayama T.,Japan Science and Technology Agency
Carcinogenesis | Year: 2012
Using the PCR-based subtractive messenger RNA hybridization assay described in this paper, we isolated a hitherto uncharacterized gene, transmembrane protein 207 (TMEM207), which was selectively expressed in collagen gel-invading cultured signet-ring cell carcinoma KATO-III cells. TMEM207 has a C-terminal proline-rich PPxY motif, which binds to the WW domain-containing oxidoreductase, WWOX. Enforced expression of TMEM207 significantly increased Matrigel invasion activity of KATO-III cells in vitro without affecting cell growth. In contrast, expression of TMEM207 with mutations in the PPxY motif did not significantly increase Matrigel invasion activity of KATO-III cells. Immunohistochemical staining showed that TMEM207 was strongly expressed in 7 of 30 gastric signet-ring cell carcinoma tissue specimens. Notably, TMEM207 expression was associated with the depth of cancer invasion and the presence of lymph node metastasis. The results of co-immunoprecipitation followed by western immunoblotting showed that TMEM207 is bound to WWOX in a PPxY motif-dependent manner. Small interfering RNA-mediated downregulation of WWOX also significantly increased Matrigel invasion activity of KATO-III cells. Notably, exogenous expression of TMEM207 impaired the WWOX-mediated repression of Matrigel invasion activity of another cultured signet-ring cell carcinoma cell line, NUGC-4 cells. Recent studies have highlighted the fact that WWOX acts as a tumor suppressor factor in various malignant tumors, including gastric cancer. On the basis of these findings and the results of the present study, we think that overexpression of TMEM207 may facilitate invasive activity and metastasis of gastric signet-ring cell carcinoma, which possibly occur through binding to WWOX and attenuation of its function. © The Author 2012. Published by Oxford University Press. All rights reserved.
Shinkuma S.,Hokkaido University
Clinical, Cosmetic and Investigational Dermatology | Year: 2015
Dystrophic epidermolysis bullosa is a rare inherited blistering disorder caused by mutations in the COL7A1 gene encoding type VII collagen. The deficiency and/or dysfunction of type VII collagen leads to subepidermal blistering immediately below the lamina densa, resulting in mucocutaneous fragility and disease complications such as intractable ulcers, extensive scarring, malnutrition, and malignancy. The disease is usually diagnosed by immunofluorescence mapping and/or transmission electron microscopy and subsequently subclassified into one of 14 subtypes. This review provides practical knowledge on the disease, including new therapeutic strategies. © 2015 Shinkuma.
Hasegawa Y.,Hokkaido University
Chemistry Letters | Year: 2013
Magnetic semiconductor nanocrystals composed of lanthanoid ions, europium chalcogenide nanocrystals (EuX: EuO, EuS, and EuSe nanocrystals), are characterized by the narrow 4f orbitals that exist as degenerate levels between the conduction band [5d orbitals of Eu(II)] and the valence band (p orbitals of O2-, S2-, and Se2-). In this review, syntheses and characteristic photophysical properties of EuX nanocrystals are introduced. EuX nanocrystals are expected to be useful in applications such as future optical isolators, optomagnetic and spintronic devices. © 2013 The Chemical Society of Japan.
Honma K.-I.,Hokkaido University
Brain and Nerve | Year: 2012
Under temporal isolation, the human sleep-wake cycle occasionally desynchronizes from the circadian rhythms in deep body temperature and plasma melatonin. Such internal desynchronization is observed even in the real world. Two distinct models are advanced for the sleep-wake cycle; one is a two-oscillator model and the other is a two-process model. However, our recent studies in human subjects under temporal isolation support the former model. Internal desynchronization is unique to the human sleep-wake cycle and has been never observed in other mammal species. Therefore, a specific animal model for the human sleep-wake cycle is needed to explore the brain mechanism. By chronic treatment with methamphetamine (MAP), a stimulant of the central dopaminergic system, in drinking water, rats showed behavioral rhythms which were independent of the circadian pacemaker in the suprachiasmatic nucleus (SCN), the central clock entraining to light-dark cycles. Furthermore, MAP treatment induces internal desynchronization between the MAP-induced behavioral rhythms and the circadian rhythms of clock gene expression in the SCN, suggesting a presence of a secondary pacemaker outside the SCN that regulates the sleep-wake cycle. These findings are consistent with the two-oscillator model mentioned previously. According to the current understanding of the circadian system in mammals, there are a number of so-called peripheral clocks in the body which are regulated by the central clock in the SCN. Taking advantage of the MAP-induced internal desynchronization, attempts have been made to identity the peripheral clock(s) regulating the sleep-wake cycle. The nigrostriatal dopaminergic system is a possible site of the behavior-associated peripheral clock.
Koike T.,Hokkaido University
Arthritis Research and Therapy | Year: 2012
The hallmarks of IgG4-related disease (IgG4-RD) are lymphoplasmacytic tissue infiltration with a predominance of IgG4-positive plasma cells, accompanied by fibrosis, obliterative phlebitis, dacryoadenitis, and elevated levels of IgG4. In a recent issue of Arthritis Research & Therapy, Tsuboi and colleagues demonstrated that regulatory T (Treg) cell-and T helper 2 (Th2) cell-derived cytokines contribute to the pathogenesis of Mikulicz's disease, an activation pathway that appears to be common for IgG4-RD. Additional organ-specific factors may account for the different organ involvement of IgG4-RD. © 2013 BioMed Central Ltd.
Dairi T.,Hokkaido University
Methods in Enzymology | Year: 2012
In prokaryotes, menaquinone (MK) is involved in an electron-transfer pathway. Its biosynthesis was established in the 1970s and 1980s with Escherichia coli. However, a bioinformatic analysis of whole genome sequences has suggested the presence of an alternative pathway. We investigated a novel pathway in a Streptomyces strain. The 13C-labeling pattern of MK purified from a Streptomyces strain grown on [U-13C]glucose was quite different from that of E. coli. We searched for candidate genes participating in the pathway by in silico screening, and the involvement of these genes in the pathway was confirmed by gene-disruption experiments. We also employed mutagenesis to isolate auxotrophic mutants and used these mutants as hosts for shotgun cloning experiments. Metabolites that accumulated in the culture broth of the mutants were isolated and their structures were determined. Taken together, the results indicated an alternative pathway (futalosine (FL) pathway). Moreover, there were three possible routes in the early part of the FL pathway. FL was directly formed by MqnA in Thermus thermophilus and converted into dehypoxanthinyl FL (DHFL). In Acidothermus cellulolyticus, Streptomyces coelicolor, and Helicobacter pylori, aminodeoxyfutalosine (AFL) was formed by MqnA. In the case of the former two strains, AFL was converted to FL by deaminases then to DHFL. In contrast, AFL was directly converted to DHFL in H. pylori. © 2012 Elsevier Inc.
Suwa T.,Hokkaido University |
Usui T.,Soka University
Environmental Economics and Policy Studies | Year: 2014
This article examines the reducing and recycling effects caused by municipal solid waste policies, such as garbage pricing and recyclables collection. Equations for garbage and recyclables are estimated using Heckman’s two-step estimation and seemingly unrelated regression (SUR) to consider sample selection bias and the correlation between garbage and recyclables emission. The estimation results suggest that municipal PET bottle collection leads to a reduction in the amount of garbage collected. Furthermore, the results reveal that garbage pricing increases the quantity of PET bottles collected, while it decreases the amount of garbage. © 2007, Springer Japan.
Soga M.,Hokkaido University |
Koike S.,Tokyo University of Agriculture and Technology
Animal Conservation | Year: 2013
Cities are expanding rapidly worldwide. Modern cities are expected to carry heavy extinction debts owing to their recent and drastic fragmentation histories. Therefore, detecting extinction debt and identifying species threatened by it in recently created cities are necessary to prevent future biodiversity losses. Here, we studied the relationship between the life-history traits of butterfly species and the extent of their extinction debts using two different methodological approaches in Tokyo, central Japan. First, we compared the effects of current and past landscape parameters on current species richness using generalized linear models. Second, we predicted species richness in unstable (i.e. high loss) habitats using a model developed for stable (i.e. low loss) habitats. The difference between predicted and observed species richness was used to estimate the extinction debt (the number of species expected to go extinct). We classified butterfly species as seasonal specialists or generalists and as habitat specialists or generalists based on their life-history traits. With both methods, we found significant extinction debts only for specialist species. Mapping the potential extinction debts within our study area indicated that currently large patches had relatively low extinction debts, whereas small patches often had high extinction debts. These results suggested that improving patch area, connectivity and especially quality, would have more significant impacts in small patches than in large ones. Extinction debt is an important concept for setting conservation priorities in highly fragmented landscapes, especially in urban areas. © 2012 The Zoological Society of London.
Elm M.T.,Justus Liebig University |
Hara S.,Hokkaido University
Advanced Materials | Year: 2014
Granular hybrid structures containing ferromagnetic nanoclusters embedded in a semiconducting matrix are an interesting class of materials as their properties can be tuned in a wide range. Hybrids are a promising alternative to dilute magnetic semiconductors in the field of spintronics and magnetoelectronics, because the nanoclusters can show ferromagnetic behavior even at room temperature. In this review, it is focused on the rather well investigated dilute magnetic semiconductor (Ga,Mn)As with MnAs inclusions. Different preparation methods are presented which were developed over the last two decades in order to obtain MnAs nanoclusters in the semiconducting matrix and to tune the structural and magnetic properties of these clusters. Recent results on the influence of the nanoclusters on the hybrids' transport properties as well as first approaches to use hybrids with a random nanocluster distribution in new spintronic devices are discussed. In addition, the perspective of using single MnAs nanoclusters as well as ordered arrangements of a few nanoclusters in new planar magnetoelectronic devices is illustrated. © 2014 Wiley-VCH Verlag GmbH & Co. KGaA.
Ogi M.,Japan Agency for Marine - Earth Science and Technology |
Yamazaki K.,Hokkaido University |
Wallace J.M.,University of Washington
Geophysical Research Letters | Year: 2010
Based on a statistical analysis incorporating 925-hPa wind fields from the NCEP/NCAR Reanalyses, it is shown that the combined effect of winter and summer wind forcing accounts for 50% of the variance of the change in September Arctic sea ice extent from one year to the next (SIE) and it also explains roughly 1/3 of the downward linear trend of SIE over the past 31 years. In both seasons meridional wind anomalies to the north and east of Greenland are correlated with September SIE, presumably because they modulate the export of ice through Fram Strait. Anticyclonic wind anomalies over the Beaufort Sea during summer favor low September SIE and have contributed to the record-low values in recent summers, perhaps by enhancing the flux of ice toward Fram Strait in the trans-polar drift. Copyright © 2010 by the American Geophysical Union.
Fujii Y.,Hokkaido University
Journal of Atmospheric and Solar-Terrestrial Physics | Year: 2011
This study suggests that the cause of the stagnation in global warming in the mid 20th century was the atmospheric nuclear explosions detonated between 1945 and 1980. The estimated GST drop due to fine dust from the actual atmospheric nuclear explosions based on the published simulation results by other researchers (a single column model and Atmosphere-Ocean General Circulation Model) has served to explain the stagnation in global warming. Atmospheric nuclear explosions can be regarded as full-scale in situ tests for nuclear winter. The non-negligible amount of GST drop from the actual atmospheric explosions suggests that nuclear winter is not just a theory but has actually occurred, albeit on a small scale. The accuracy of the simulations of GST by IPCC would also be improved significantly by introducing the influence of fine dust from the actual atmospheric nuclear explosions into their climate models; thus, global warming behavior could be more accurately predicted. © 2011 Elsevier Ltd.
Yoshida-Noro C.,Nihon University |
Tochinai S.,Hokkaido University
Development Growth and Differentiation | Year: 2010
Enchytraeus japonensis is a small oligochaete species that proliferates asexually via fragmentation and regeneration. As sexual reproduction can also be induced, it is a good model system for the study of both regenerative and germline stem cells. It has been shown by histological study that putative mesodermal stem cells called neoblasts, and dedifferentiated epidermal and endodermal cells are involved in blastema formation. Recently, we isolated three region-specific marker genes expressed in the digestive tract and showed by in situ hybridization that morphallactic as well as epimorphic regulation of the body patterning occurs during regeneration. We also cloned two vasa-related genes and analyzed their expression during development and in mature worms that undergo sexual reproduction. The results arising form these studies suggest that the origin and development of germline stem cells and neoblasts may be independent. Furthermore, we carried out functional analysis using RNA interference (RNAi) and showed that a novel gene termed grimp is required for mesodermal cell proliferation at the initial stages of regeneration. These findings indicate that the stem cell system in E. japonensis is regulated by both internal and external environmental factors. © 2009 Japanese Society of Developmental Biologists.
Flajnik M.F.,University of Maryland, Baltimore |
Kasahara M.,Hokkaido University
Nature Reviews Genetics | Year: 2010
The adaptive immune system (AIS) in mammals, which is centred on lymphocytes bearing antigen receptors that are generated by somatic recombination, arose approximately 500 million years ago in jawed fish. This intricate defence system consists of many molecules, mechanisms and tissues that are not present in jawless vertebrates. Two macroevolutionary events are believed to have contributed to the genesis of the AIS: the emergence of the recombination-activating gene (RAG) transposon, and two rounds of whole-genome duplication. It has recently been discovered that a non-RAG-based AIS with similarities to the jawed vertebrate AIS including two lymphoid cell lineages arose in jawless fish by convergent evolution. We offer insights into the latest advances in this field and speculate on the selective pressures that led to the emergence and maintenance of the AIS. © 2010 Macmillan Publishers Limited. All rights reserved.
Katsumata K.,Hokkaido University
Journal of Geophysical Research: Solid Earth | Year: 2011
The 2003 Tokachi-oki earthquake (Mw = 8.3) occurred on 26 September 2003 off the pacific coast of Hokkaido, Japan. In the present study, an earthquake catalog is used that lists 2,000 earthquakes with M 3.3. All of the earthquake waveforms were recorded by the Institute of Seismology and Volcanology, Hokkaido University. In the present study, these waveforms are manually re-examined, and hypocenters and magnitudes are re-calculated. A detailed analysis of the re-determined earthquake catalog between 1994 and 2003 using a gridding technique (ZMAP) shows that the 2003 Tokachi-oki earthquake is preceded by two neighboring seismic quiescence anomalies that start around the beginning of 1999, and last about 5 years, until the main shock occurs. These quiescence anomalies are located around the asperity ruptured by the main shock, and the Z-values are +3.9 and +4.0 for a time window of Tw = 4 years, using a sample size of N = 100 earthquakes. The detected seismic quiescences can be interpreted as being caused by a decrease of 50% in the stressing rate based on Dieterich's theory. It is proposed that a quasi-static pre-slip occurs at the northeastern edge of the asperity ruptured by the main shock, and lasts for five years until the main shock occurs. By calculating the change in the Coulomb failure stress (CFS), it is found that negative CFS areas are consistent with the two quiescence anomalies, and a positive CFS area corresponds to the hypocenter of the main shock, indicating that the quasi-static pre-slip model is a plausible one. Copyright 2011 by the American Geophysical Union.
Ariga T.,Hokkaido University
Allergology International | Year: 2012
Wiskott-Aldrich syndrome (WAS) is an X-linked primary immunodeficiency disease with unique and characteristic features. In 1994, the responsible gene for WAS, the WASP gene on X-chromosome, was identified. Since then, renewed clinical and basic researches of WAS have started and remarkably developed. I will comment on recent progress in the clinical and basic researches of WAS, including some topics reported by our and other groups. ©2012 Japanese Society of Allergology.
Saitoh K.,Hokkaido University |
Matsuo S.,Fujikura Ltd
Journal of Lightwave Technology | Year: 2016
Multicore fibers (MCFs) are expected as a good candidate for overcoming the capacity limit of a current optical communication system. This paper describes the recent progress on the MCFs for space-division multiplexing to be utilized in future large capacity long-distance transmission systems. Tradeoff issue between low crosstalk and high core density in MCFs is presented and prospect of large-space multiplicity of MCFs is discussed. © 1983-2012 IEEE.
Okajima T.,Hokkaido University
Current Pharmaceutical Biotechnology | Year: 2012
Rheological properties of living cells play important roles in regulating their various biological functions. Therefore, measuring cell rheology is crucial for not only elucidating the relationship between the cell mechanics and functions, but also mechanical diagnosis of single cells. Atomic force microscopy (AFM) is becoming a useful technique for single cell diagnosis because it allows us to measure the rheological properties of adherent cells at any region on the surface without any modifications. In this review, we summarize AFM techniques for examining single cell rheology in frequency and time domains. Recent applications of AFM for investigating the statistical analysis of single cell rheology in comparison to other micro-rheological techniques are reviewed, and we discuss what specificity and universality of cell rheology are extracted using AFM. © 2012 Bentham Science Publishers.
Ueda H.,Hokkaido University
Journal of Fish Biology | Year: 2012
After several years of feeding at sea, salmonids have an amazing ability to migrate long distances from the open ocean to their natal stream to spawn. Three different research approaches from behavioural to molecular biological studies have been used to elucidate the physiological mechanisms underpinning salmonid imprinting and homing migration. The study was based on four anadromous Pacific salmon Oncorhynchus spp., pink salmon Oncorhynchus gorbuscha, chum salmon Oncorhynchus keta, sockeye salmon Oncorhynchus nerka and masu salmon Oncorhynchus masou, migrating from the North Pacific Ocean to the coast of Hokkaido, Japan, as well as lacustrine O. nerka and O. masou in Lake Toya, Hokkaido, where the lake serves as the model oceanic system. Behavioural studies using biotelemetry techniques showed swimming profiles from the Bering Sea to the coast of Hokkaido in O. keta as well as homing behaviours of lacustrine O. nerka and O. masou in Lake Toya. Endocrinological studies on hormone profiles in the brain-pituitary-gonad axis of O. keta, and lacustrine O. nerka identified the hormonal changes during homing migration. Neurophysiological studies revealed crucial roles of olfactory functions on imprinting and homing during downstream and upstream migration, respectively. These findings are discussed in relation to the physiological mechanisms of imprinting and homing migration in anadromous and lacustrine salmonids. © 2012 The Author. Journal of Fish Biology © 2012 The Fisheries Society of the British Isles.
Kasedou M.,Hokkaido University
Journal of Geometry and Physics | Year: 2010
We investigate the differential geometry of spacelike submanifolds of codimension two in de Sitter space and classify the singularities of lightlike hypersurfaces and lightcone Gauss maps in de Sitter 4-space. © 2009 Elsevier B.V. All rights reserved.
Yoshida F.,Hokkaido University
Environmental Economics and Policy Studies | Year: 2010
The three main areas where information and communication technology (ICT) impacts on the environment are considered: (1) the fallout from the processes of production, (2) the environmental burden of ICT products themselves and their use, and (3) the recycling and disposing of ICT products. On the basis of this overview, a number of environmental policies are proposed. A participatory system needs to be established between regional offices and all interested parties. © 2010 Springer.
Tadano S.,Hokkaido University
Sensors (Basel, Switzerland) | Year: 2013
This paper proposes a method for three dimensional gait analysis using wearable sensors and quaternion calculations. Seven sensor units consisting of a tri-axial acceleration and gyro sensors, were fixed to the lower limbs. The acceleration and angular velocity data of each sensor unit were measured during level walking. The initial orientations of the sensor units were estimated using acceleration data during upright standing position and the angular displacements were estimated afterwards using angular velocity data during gait. Here, an algorithm based on quaternion calculation was implemented for orientation estimation of the sensor units. The orientations of the sensor units were converted to the orientations of the body segments by a rotation matrix obtained from a calibration trial. Body segment orientations were then used for constructing a three dimensional wire frame animation of the volunteers during the gait. Gait analysis was conducted on five volunteers, and results were compared with those from a camera-based motion analysis system. Comparisons were made for the joint trajectory in the horizontal and sagittal plane. The average RMSE and correlation coefficient (CC) were 10.14 deg and 0.98, 7.88 deg and 0.97, 9.75 deg and 0.78 for the hip, knee and ankle flexion angles, respectively.
Ohtani B.,Hokkaido University
Physical Chemistry Chemical Physics | Year: 2014
Although the history of photocatalysis research is not so long, many researchers have studied photocatalysis and a large number of papers on photocatalysis have been published. The objectives of this review paper are to revisit the fundamentals of photocatalysis, especially its thermodynamics and kinetics, which have not been reexamined in recent studies, to clarify the problems, if any, that prevent developments in the field of photocatalysis, and to present insights for future progress. This journal is © 2014 the Owner Societies.
Ohtani B.,Hokkaido University
Electrochemistry | Year: 2014
Important papers related to photocatalysis published in the early 1980's or before, some of which are not included in databases, e.g., Web of Science, or not digitized in electronic files, are reviewed in chronological order. Metal deposition, diffuse reflection spectroscopy, dye degradation, paint chalking, quantitative analysis of composition, Xray diffraction analysis of anatase-rutile mixture, radical chain reaction, band-structure model, Langmuir adsorption in kinetics, Honda-Fujishima effect, dye-sensitized reaction, hydrogen evolution using sacrificial agents, Scaife's plot and photocatalytic water splitting are discussed. © The Electrochemical Society of Japan, All rights reserved.
Isegawa M.,Kyoto University |
Maeda S.,Hokkaido University |
Tantillo D.J.,University of California at Davis |
Morokuma K.,Kyoto University
Chemical Science | Year: 2014
Application of the Artificial Force Induced Reaction (AFIR) method to the prediction of cyclization/rearrangement pathways for carbocation precursors to sesquiterpenes is described. This method captures many of the features revealed in previous studies as well as new ones, including a pathway to a sesquiterpene not yet isolated in nature that we suspect will be isolated in time. © 2014 The Royal Society of Chemistry.
Saito K.,Hokkaido University
Cell structure and function | Year: 2011
Laser-scanning confocal microscopy has been employed for exploring structures at subcellular, cellular and tissue level in three dimensions. To acquire the confocal image, a coherent light source, such as laser, is generally required in conventional single-point scanning microscopy. The illuminating beam must be focused onto a small spot with diffraction-limited size, and this determines the spatial resolution of the microscopy system. In contrast, multipoint scanning confocal microscopy using a Nipkow disk enables the use of an incoherent light source. We previously demonstrated successful application of a 100 W mercury arc lamp as a light source for the Yokogawa confocal scanner unit in which a microlens array was coupled with a Nipkow disk to focus the collimated incident light onto a pinhole (Saito et al., Cell Struct. Funct., 33: 133-141, 2008). However, transmission efficiency of incident light through the pinhole array was low because off-axis light, the major component of the incident light, was blocked by the non-aperture area of the disk. To improve transmission efficiency, we propose an optical system in which off-axis light is able to be transmitted through pinholes surrounding the pinhole located on the optical axis of the collimator lens. This optical system facilitates the use of not only the on-axis but also the off-axis light such that the available incident light is considerably improved. As a result, we apply the proposed system to high-speed confocal and multicolor imaging both with a satisfactory signal-to-noise ratio.
Hasegawa Y.,Hokkaido University
Bulletin of the Chemical Society of Japan | Year: 2014
In this account, lanthanoid complexes, coordination polymers, and nanocrystals with photofunctional properties are introduced. To maintain the effective emission of Nd(III), Sm(III), Eu(III), Tb(III), and Yb(III) ions in organic media, the coordination sphere of the lanthanoid ions should consist of strong, bulky, and asymmetric ligands with low vibrational frequencies, that is, there are three criteria for luminescence: 1) suppression of vibrational relaxation, 2) prevention of nonradiative cross relaxation at diffusional collision, and 3) introduction of asymmetric coordination geometry for enhancing electric dipole transition. Lanthanoid coordination compounds with characteristic photosensitizing properties, photochromic properties, circularly polarized luminescence (CPL), metal ion sensing properties, solvent sensing properties, energy-conversion properties, thermostable properties, triboluminescent properties, and thermosensing properties are also described for the development of photofunctional materials. In the second half, the synthesis, photophysical magnetic, and magneto-optical properties of lanthanoid nanocrystals, EuO, EuS, and EuSe, are reported. In particular, the remarkable photophysical properties of nanoaggregates composed of EuS nanocrystals are presented. Photofunctional lanthanoid(III) complexes, coordination polymers, and nanocrystals are expected to open up a frontier field of materials science. © 2014 The Chemical Society of Japan.
Tsubakino D.,Hokkaido University |
Hara S.,University of Tokyo
Systems and Control Letters | Year: 2012
This paper proposes an eigenvector-based method for analysis and design of hierarchical networks for multi-agent systems. We first define the concept of eigen-connection by characterizing low rank information flow between layers based on the eigenvector of lower level interconnection structures. It is shown that the resulting intergroup interconnections affect only a few eigenvalues of interconnection structures in the lower layer, and we derive explicit expressions for shifted eigenvalues. Then a procedure for designing hierarchical networks that result in desirable eigenvalue distributions is proposed, where the eigen-connection is used for a key to move undesirable eigenvalues selectively. The effectiveness of the procedure is demonstrated by a numerical example. © 2011 Elsevier B.V. All rights reserved.
Takeuchi H.,Hokkaido University
Journal of Computational Chemistry | Year: 2010
Geometry optimization of acetylene clusters (HCCH)n in the range of n ≤ 55 was carried out with a recently proposed intermolecular potential consisting of Morse potentials, damped dispersion terms, and damped Coulomb terms. The heuristic method developed by the present author was used in the optimization: optimal geometries were searched by using geometry perturbations and subsequent local optimizations. The calculations were repeated until the global minimum was found for each cluster at least three times. The obtained results were analyzed to examine structural evolution of the clusters. The geometries of the clusters with n ≥ 25 were similar to the geometry in the cubic crystal of acetylene whereas smaller clusters take icosahedron-based geometries. © 2010 Wiley Periodicals, Inc.
Akhter A.,Hokkaido University
International journal of pharmaceutics | Year: 2013
Liver dysfunction is associated with a variety of liver diseases, including viral or alcoholic hepatitis, fibrosis, cirrhosis, and portal hypertension. A targeted drug delivery system would be very useful in the treatment of these diseases. We herein describe the development of a system comprised of a new peptide-lipid conjugate for the efficient delivery of molecules to LEC. The RLTRKRGLK sequence (3359-3367), which mediates the association of LDL with arterial CSPG and an LDL receptor, was utilized as a ligand for achieving this goal. The peptide modified PEG-LPs (RLTR-PEG-LPs) were efficiently taken up by primary liver endothelial cells (liver ECs) and other types of cells. In vivo biodistribution and confocal microscopy analysis showed that RLTR-PEG-LPs became widely accumulated in LECs within a short time. Distribution of RLTR-PEG-LPs was greatly reduced with a pretreatment of unlabeled RLTR-PEG-LPs, not cationic LPs, indicating that the sequence is important for LECs. The findings indicate that a reverse sequence of RLTR (KLGR) modified PEG-LPs (KLGR-PEG-LP) did the same pattern compared with RLTR-PEG-LPs, suggesting that the RKR or RXXR sequence might be essential for LECs targeting. Collectively RLTR-PEG-LPs and KLGR-PEG-LPs have the potential for delivering drugs to LECs. Copyright © 2013 Elsevier B.V. All rights reserved.
Nakayama R.,Hokkaido University
Progress of Theoretical Physics | Year: 2012
A simple conformal quantum mechanics model of a d-component variable is proposed, which exactly reproduces the retarded Green functions and conformal weights of conformally coupled scalar fields in de Sitter spacetime seen by a static patch observer. It is found that the action integral of this model is automatically expressed by a complex integral over the time variable t along a closed contour in a way that is typical to the Schwinger-Keldysh formalism of a thermofield theory. Hence, this model is at finite temperature. The case of conformally coupled scalar fields in 3D Schwarzschild de Sitter space is also considered, and then a large N matrix model is obtained.
Cui X.,Japan National Institute of Advanced Industrial Science and Technology |
Tawa K.,Japan National Institute of Advanced Industrial Science and Technology |
Kintaka K.,Japan National Institute of Advanced Industrial Science and Technology |
Nishii J.,Hokkaido University
Advanced Functional Materials | Year: 2010
A two-dimensional (2D) plasmonic coupling nanostructure for enhanced fluorescence observation using a microscope is presented. The substrate contained periodically assembled nanohole arrays with a pitch of 400 nm and a depth of 2S nm. In comparison with one-dimensional (ID) gratings, this new substrate presented an excellent surface plasmon coupling ability to illuminate light from all directions. Under an optical microscope, an enhancement in the fluorescence intensity of up to 100 times compared with a plain glass slide was observed. The ability to markedly increase the fluorescence intensity means this technique has great potential for application in biodiagnostics, imaging, sensing, and photovoltaic cells. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA.
Koyanagi K.O.,Hokkaido University
Genome Biology and Evolution | Year: 2015
How cells divide and differentiate is a fundamental question in organismal development; however, the discovery of differentiation processes in various cell types is laborious and sometimes impossible. Phylogenetic analysis is typically used to reconstruct evolutionary processes based on inherent characters. It could also be used to reconstruct developmental processes based on the developmental changes that occur during cell proliferation and differentiation. In this study, DNA methylation information from differentiated hematopoietic cells was used to perform phylogenetic analyses. The results were assessed for their validity in inferring hierarchical differentiation processes of hematopoietic cells and DNA methylation processes of differentiating progenitor cells. Overall, phylogenetic analyses based on DNA methylation information facilitated inferences regarding hematopoiesis. © The Author(s) 2015.
Seya T.,Hokkaido University
Molecular immunology | Year: 2011
Measles virus (MV) V protein blocks type I IFN signaling in MV-infected cells. Previous studies suggested that some MV strains could release the V protein-mediated type I IFN suppression in affected cells by two distinct modes: V protein mutation and production of DI RNA. These two modes of type I interferon regulation involves the IPS-1 (MAVS, Cardif, VISA) pathway (Takaki et al., 2011. Mol. Immunol. 48(4), 497-504). We add the comment to this previous issue that the release of the V protein-mediated suppression of type I IFN occurs only by a laboratory-adapted strain of Edmonston.
Katoh H.,Hokkaido University |
Zheng P.,University of Michigan |
Liu Y.,Center for Cancer and Immunology Research
Journal of Autoimmunity | Year: 2013
FOXP3 plays an essential role in the maintenance of self-tolerance and, thus, in preventing autoimmune diseases. Inactivating mutations of FOXP3 cause immunodysregulation, polyendocrinopathy, and enteropathy, X-linked syndrome. FOXP3-expressing regulatory T cells attenuate autoimmunity as well as immunity against cancer and infection. More recent studies demonstrated that FOXP3 is an epithelial cell-intrinsic tumor suppressor for breast, prostate, ovary and other cancers. Corresponding to its broad function, FOXP3 regulates a broad spectrum of target genes. While it is now well established that FOXP3 binds to and regulates thousands of target genes in mouse and human genomes, the fundamental mechanisms of its broad impact on gene expression remain to be established. FOXP3 is known to both activate and repress target genes by epigenetically regulating histone modifications of target promoters. In this review, we first focus on germline mutations found in the FOXP3 gene among IPEX patients, then outline possible molecular mechanisms by which FOXP3 epigenetically regulates its targets. Finally, we discuss clinical implications of the function of FOXP3 as an epigenetic modifier. Accumulating results reveal an intriguing functional convergence between FOXP3 and inhibitors of histone deacetylases. The essential epigenetic function of FOXP3 provides a foundation for experimental therapies against autoimmune diseases. © 2013 Elsevier Ltd.
Tachikawa H.,Hokkaido University
Journal of Physical Chemistry A | Year: 2011
Electron capture dynamics of SO 2-H 2O(Ar) n complexes (n = 0-2) have been investigated by means of direct ab initio molecular dynamics (MD) method in order to elucidate the effects of solvent argon on the reaction dynamics of SO 2-H 2O. The neutral complex of SO 2-H 2O has a C s symmetry, and the sulfur of SO 2 interacts with the oxygen of H 2O with an eclipsed form. In the SO 2-H 2O(Ar) n complexes, the dipole of H 2O interacts with the argon atoms in the most stable structure. Following the electron capture of the complex SO 2-H 2O, the complex anion SO 2 -(H 2O) is dissociated directly into SO 2 - + H 2O. On the other hand, the electron capture of SO 2(H 2O)(Ar) n argon complex (n = 1-2) leads to the anion-water complex SO 2 -(H 2O) because the collision of H 2O with the Ar atom causes a rebound of H 2O from Ar atom to the SO 2 - anion. The argon solvent enhanced the SO 2 -(H 2O) complex formation. The reaction mechanism of SO 2(H 2O) in the participation of argon atoms was discussed on the basis of the present results. © 2011 American Chemical Society.
Ema T.,Okayama University |
Miyazaki Y.,Okayama University |
Shimonishi J.,Okayama University |
Maeda C.,Okayama University |
Hasegawa J.-Y.,Hokkaido University
Journal of the American Chemical Society | Year: 2014
We prepared bifunctional MgII porphyrin catalysts 1 for the solvent-free synthesis of cyclic carbonates from epoxides and CO2. The activities of 1d, 1h, and 1i, which have Br-, Cl-, and I- counteranions, respectively, increased in the order 1i < 1h < 1d. Catalysts 1d and 1j-m, which bear four tetraalkylammonium bromide groups with different alkyl chain lengths, showed comparable but slightly different activities. Based on the excellent catalyst 1d, we synthesized MgII porphyrin 1o with eight tetraalkylammonium bromide groups, which showed even higher catalytic activity (turnover number, 138,000; turnover frequency, 19,000 h-1). The catalytic mechanism was studied by using 1d. The yields were nearly constant at initial CO2 pressures in the 1-6 MPa range, suggesting that CO2 was not involved in the rate-determining step in this pressure range. No reaction proceeded in supercritical CO2, probably because the epoxide (into which the catalyst dissolved) dissolved in and was diluted by the supercritical CO2. Experiments with 18O-labeled CO2 and D-labeled epoxide suggested that the catalytic cycle involved initial nucleophilic attack of Br- on the less hindered side of the epoxide to generate an oxyanion, which underwent CO2 insertion to afford a CO2 adduct; subsequent intramolecular ring closure formed the cyclic carbonate and regenerated the catalyst. Density functional theory calculations gave results consistent with the experimental results, revealing that the quaternary ammonium cation underwent conformational changes that stabilized various anionic species generated during the catalytic cycle. The high activity of 1d and 1o was due to the cooperative action of the MgII and Br- and a conformational change (induced-fit) of the quaternary ammonium cation. © 2014 American Chemical Society.
Tamura M.,Nagoya University |
Tonomura T.,Nagoya University |
Shimizu K.-I.,Hokkaido University |
Satsuma A.,Nagoya University
Green Chemistry | Year: 2012
Among various metal oxides, cerium oxide (CeO 2) shows the highest catalytic activity for transamidation of picolinamide with n-octylamine. CeO 2 acts as a reusable and effective heterogeneous catalyst for transamidation under solvent-free conditions. Transamidation of a variety of amides and amines produced the corresponding N-alkyl amides in high yields. This method provides the first example of a heterogeneous catalyst for transamidation using aliphatic amines as substrates. Characterization of acid-base properties and kinetic studies suggest that the cooperation of the weak Lewis acid sites and adjacent strong base sites play important roles in the transamidation reaction. © The Royal Society of Chemistry 2012.
Sinthusamran S.,Prince of Songkla University |
Benjakul S.,Prince of Songkla University |
Kishimura H.,Hokkaido University
Food Chemistry | Year: 2013
Acid soluble collagens (ASCs) from skin and swim bladder of seabass (Lates calcarifer) were isolated and comparatively characterised. Higher yield (28.5%) was obtained for ASC from swim bladder, compared with that from skin (15.8%). ASCs from both skin and swim bladder had the similar protein patterns and were identified to be type I. Both α- and β-chains constituted as major components. Fourier transform infrared (FTIR) spectra revealed that both ASCs were triple helix in structure. ASC from both sources contained glycine as the major amino acid with imino acids (proline and hydroxyproline) of 194-195 residues/1000 residues). Peptide maps of both ASCs digested by chymotrypsin and trypsin showed slight differences, suggesting some differences in their primary structure. The thermal transition temperature of swim bladder ASC (35.02 °C) was slightly higher than its skin counterpart (33.33 °C). Based on zeta potential analysis, ASCs from skin and swim bladder had a net charge of zero at pH 6.46 and 6.64, respectively. Therefore, both the skin and swim bladder of seabass could be used potentially for collagen extraction. © 2012 Elsevier Ltd. All rights reserved.
Abe R.,Hokkaido University
Bulletin of the Chemical Society of Japan | Year: 2011
Photocatalytic water splitting using semiconductor materials has attracted considerable interest due to its potential for clean production of H2 from water by utilizing abundant solar light. The developments of water-splitting systems that can efficiently use visible light have been a major challenge for many years in order to realize efficient conversion of solar light. We have developed a new type of photocatalysis system that can split water into H2 and O2 under visible light irradiation, which was inspired by the two-step photoexcitation (Z-scheme) mechanism of natural photosynthesis in green plants. In this system, the water-splitting reaction is broken up into two stages: one for H2 evolution and the other for O2 evolution; these are combined by using a shuttle redox couple (Red/Ox) in the solution. The introduction of a Z-scheme mechanism reduces the energy required to drive each photocatalysis process, extending the usable wavelengths significantly (≈660 nm for H2 evolution and ≈600 nm for O2 evolution) from that in conventional water splitting systems (≈460 nm) based on one-step photoexcitation in single semiconductor material. © 2011 The Chemical Society of Japan.
Ono S.,NIPPON CHEMI - CON Co. |
Habazaki H.,Hokkaido University
Corrosion Science | Year: 2011
The pit growth process on (100) aluminium under anodic pulse current in a mixed solution of 1M HCl and 0.1M H2SO4 at 30°C has been evaluated using potential transient measurements and pit size distributions obtained by scanning electron microscopy. Sustained pit growth is observed for all pits during the initial anodic potential rise before reaching a steady-state etch potential, whereas a substantial fraction of the pits passivate at the steady-state etch potential. The pit growth rate during the initial potential rise is 3.4μms-1, which is similar to that at the steady-state etch potential. The growth rates of active pits are potential-independent. © 2011 Elsevier Ltd.
Ujiie H.,Hokkaido University
Journal of Dermatological Science | Year: 2015
Bullous pemphigoid (BP) is a common autoimmune blistering skin disease in which two hemidesmosomal components - the transmembrane collagen XVII (BP180 or BPAG2) and the plakin family protein BP230 (BPAG1) - are targeted by autoimmunity. Of these, collagen XVII (COL17) is thought to be a major autoantigen, and vital roles of IgG autoantibodies in blister formation have been elucidated. However, BP shows distinct features, including pruritic urticarial erythema and eosinophilic infiltration, which may be independent of IgG-mediated autoimmunity. Recently, it has been revealed that sera from certain patients with BP contain IgE autoantibodies to COL17 and that IgE autoantibodies bind to peri-lesional dermal-epidermal junctions. Mouse models have demonstrated that IgE antibodies to COL17 induce erythema and eosinophilic infiltration in skin. In addition, the successful treatment of severe BP with omalizumab, a humanized monoclonal antibody targeting IgE, has been reported. These findings suggest that both IgG and IgE autoantibodies to COL17 may be involved in the BP pathogenesis. This article summarizes IgE-mediated autoimmunity to COL17 in BP. © 2015 Japanese Society for Investigative Dermatology.
Yoshioka E.,Asahikawa University |
Hanley S.J.B.,Hokkaido University |
Kawanishi Y.,Asahikawa University |
Saijo Y.,Asahikawa University
British Journal of Psychiatry | Year: 2014
Background: The charcoal burning suicide epidemics in both Hong Kong and Taiwan have been well documented. However, little is known about the situation in Japan. Aims: To examine the impact of charcoal burning suicide on the overall and other method-specific suicide rates between 1998 and 2007 in Japan. Method: Using data obtained from the Vital Statistics of Japan, negative binomial regression analyses were performed to investigate the impact of the charcoal burning method. Results: In males and females aged 15-24 and 25-44 years, the charcoal burning epidemic led to a substantial increase in overall suicides, without a decrease in other methods. In all other age groups, no such trend was observed. Conclusions: In young Japanese, the charcoal burning method may have appealed to individuals who might not have chosen other highly or relatively lethal methods, and consequently led to an increase in overall suicides.
Greve R.,Hokkaido University |
Herzfeld U.C.,University of Colorado at Boulder
Annals of Glaciology | Year: 2013
The dynamic/thermodynamic shallow-ice model SICOPOLIS is applied to the Greenland ice sheet. Paleoclimatic spin-ups from 125 ka BP until today, as well as future-climate experiments 500 years into the future, are carried out with three different grid spacings, namely 20, 10 and 5 km. The scenarios are a subset of those specified by the SeaRISE (Sea-level Response to Ice Sheet Evolution) community effort. The bed topography includes improved troughs for Jakobshavn Isbræ, Helheim, Kangerdlugssuaq and Petermann glaciers, processed by an algorithm that preserves shape, orientation and continuity of the troughs on the 5 km scale. Comparison of simulated and observed present-day surface velocities shows that these ice streams and outlet glaciers are resolved with different accuracies, ranging from poor (20 km grid) to reasonably good (5 km grid). In the future-climate experiments, the simulated absolute ice volumes depend significantly on the resolution, while the sensitivities (ice volumes relative to the constant-climate control run) vary only by a few centimeters of sea-level equivalent. © 2013 Publishing Technology.
Toyoda K.,Hokkaido University |
Tebo B.M.,Oregon Health And Science University
Geochimica et Cosmochimica Acta | Year: 2013
Manganese(IV) oxides, believed to form primarily through microbial activities, are extremely important mineral phases in marine environments where they scavenge a variety of trace elements and thereby control their distributions. The presence of various ions common in seawater are known to influence Mn oxide mineralogy yet little is known about the effect of these ions on the kinetics of bacterial Mn(II) oxidation and Mn oxide formation. We examined factors affecting bacterial Mn(II) oxidation by spores of the marine Bacillus sp. strain SG-1 in natural and artificial seawater of varying ionic conditions. Ca2+ concentration dramatically affected Mn(II) oxidation, while Mg2+, Sr2+, K+, Na+ and NO3 - ions had no effect. The rate of Mn(II) oxidation at 10mM Ca2+ (seawater composition) was four or five times that without Ca2+. The relationship between Ca2+ content and oxidation rate demonstrates that the equilibrium constant is small (on the order of 0.1) and the binding coefficient is 0.5. The pH optimum for Mn(II) oxidation changed depending on the amount of Ca2+ present, suggesting that Ca2+ exerts a direct effect on the enzyme perhaps as a stabilizing bridge between polypeptide components.We also examined the effect of varying concentrations of NaCl or KNO3 (0-2000mM) on the kinetics of Mn(II) oxidation in solutions containing 10mM Ca2+. Mn(II) oxidation was unaffected by changes in ionic strength (I) below 0.2, but it was inhibited by increasing salt concentrations above this value. Our results suggest that the critical coagulation concentration is around 200mM of salt (I=ca. 0.2), and that the ionic strength of seawater (I>0.2) accelerates the precipitation of Mn oxides around the spores. Under these conditions, the aggregation of Mn oxides reduces the supply of dissolved O2 and/or Mn2+ and inhibits the Mn(II)→Mn(III) step controlling the enzymatic oxidation of Mn(II). Our results suggest that the hardness and ionic strength of the aquatic environment at circumneutral pH strongly influences the rate of biologically mediated Mn(II) oxidation. © 2012 Elsevier Ltd.
Koizumi I.,Hokkaido University
Ecology of Freshwater Fish | Year: 2011
Spatial structures can drive population dynamics and persistence. The roles of space and dispersal on dynamics, however, remain largely unknown in wild populations, mainly because of the difficulty in extensive/intensive field surveys at multiple locations. Here, I integrate results of ecological, demographic and genetic studies to elucidate detailed population structure and to identify the mechanisms of population persistence in a stream fish. Spatial structures, such as habitat size and connectivity, are particularly important in river and freshwater networks because such ecosystems are highly vulnerable to human activities. These issues are explored by examining results from a decadal research on the stream-dwelling Dolly Varden charr in the Sorachi River basin, Japan. More than 100 local habitats (i.e. tributaries) were examined for spatial structure of populations by, such as, species presence, population census, redd counts, analysis of population synchrony and microsatellite DNA analysis. The results indicate that (i) population demography is largely independent in each tributary, (ii) some large tributaries support self-sustaining populations, (iii) despite small population sizes in most tributaries (<30 spawning females), local extinction is rare, except in human-influenced areas and (iv) probabilities of extinction are likely reduced by immigration of fish from neighbouring tributaries. The evidence suggests that Dolly Varden in this river system function as a source-sink or mainland-island metapopulation structure and that processes influencing these structures vary within the stream network. Overall, local populations may be highly persistent as long as local populations are well connected. I also discuss the vulnerability of stream fishes to habitat alterations. © 2011 John Wiley & Sons A/S.
Namekata D.,Japan National Astronomical Observatory |
Habe A.,Hokkaido University
Astrophysical Journal | Year: 2011
We investigate the gas supply process from a nuclear gas disk to the Galactic center by performing two-dimensional hydrodynamic simulations including self-gravity and radiative cooling. We assume that the gas is supplied to the nuclear gas disk by the host galaxy disk. We show that many gas clumps are formed in the nuclear gas disk after the nuclear gas disk becomes massive enough to become gravitationally unstable. Coalescence of the gas clumps leads to the formation of more massive gas clumps. Gravitational encounters between these massive gas clumps induce angular momentum transfer between the gas clumps. Massive gas clumps that lose their angular momentum due to gravitational encounters move to the galactic center. In this way, the gas supply to the galactic center is realized. We also perform a numerical simulation with twice the spatial resolution to check numerical resolution effects. Time evolution of azimuthally averaged surface density distributions in both models agree well with each other. The high-mass part of the clump mass function in the low-resolution model is in good agreement with that of the high-resolution model, and lower mass clumps are well resolved in the high-resolution model. Therefore, we conclude that massive gas clumps play a major role in the angular momentum transfer. The gas supply rate to the center is about half of the gas supply rate from the host galaxy when the whole region of the nuclear gas disk becomes self-gravitationally unstable. More massive gas clumps are formed and migrate to the Galactic center in the models of the higher gas supply rate from the host galaxy. © 2011. The American Astronomical Society. All rights reserved.
Kuwano-Yoshida A.,Japan Agency for Marine - Earth Science and Technology |
Minobe S.,Hokkaido University |
Xie S.-P.,University of Hawaii at Manoa
Journal of Climate | Year: 2010
The precipitation response to sea surface temperature (SST) gradients associated with the Gulf Stream is investigated using an atmospheric general circulation model. Forced by observed SST, the model simulates a narrow band of precipitation, surface convergence, and evaporation that closely follows the Gulf Stream, much like satellite observations. Such a Gulf Stream rainband disappears in the model when the SST front is removed by horizontally smoothing SST. The analysis herein shows that it is convective precipitation that is sensitive to SST gradients. The Gulf Stream anchors a convective rainband by creating surface wind convergence and intensifying surface evaporation on the warmer flank. Deep convection develops near the Gulf Stream in summer when the atmosphere is conditionally unstable. As a result, a narrow band of upward velocity develops above the Gulf Stream throughout the troposphere in summer, while it is limited to the lower troposphere in other seasons. © 2010 American Meteorological Society.
Asakura K.,Hokkaido University
Catalysis | Year: 2012
Polarization-dependent total reflection fluorescence-extended X-ray absorption fine structure (PTRF-EXAFS) is a powerful tool to investigate the structures of highly dispersed metal clusters on oxide surfaces that provide a model system for supported metal catalysts. PTRF-EXAFS provides three-dimensional structural information of the dispersed metal clusters, in addition to the metal-support interface structure in the presence of a gas phase. Results from PTRF-EXAFS have revealed that the metal species interacts strongly with surface anions. Finally the future of PTRFEXAFS is discussed in combination with the next generation light sources, such as X-ray free electron laser (XFEL) and energy recovery linac (ERL). © The Royal Society of Chemistry 2012.
Li J.,Harvard University |
Malaby A.W.,University of Massachusetts Medical School |
Famulok M.,University of Bonn |
Sabe H.,Hokkaido University |
And 2 more authors.
Developmental Cell | Year: 2012
The glucose transporter type 4 (glut4) is critical for metabolic homeostasis. Insulin regulates glut4 by modulating its expression on the cell surface. This regulation is mainly achieved by targeting the endocytic recycling of glut4. We identify general receptor for 3-phosphoinositides 1 (Grp1) as a guanine nucleotide exchange factor for ADP-ribosylation factor 6 (ARF6) that promotes glut4 vesicle formation. Grp1 also promotes the later steps of glut4 recycling through ARF6. Insulin signaling regulates Grp1 through phosphorylation by Akt. We also find that mutations that mimic constitutive phosphorylation of Grp1 can bypass upstream insulin signaling to induce glut4 recycling. Thus, we have uncovered a major mechanism by which insulin regulates glut4 recycling. Our findings also reveal the complexity by which a single small GTPase in vesicular transport can coordinate its multiple steps to accomplish a round of transport.
Konishi K.,Hokkaido University
Structure and Bonding | Year: 2014
Synthetic techniques, geometrical structures, and electronic absorption spectra of phosphine-coordinated pure-gold molecular clusters (PGCs) accumulated over 40 years are comprehensively collected especially for those with unambiguous X-ray crystal structures available. Inspection of the electronic absorption spectra from geometrical aspects reveals that their optical properties are highly dependent on the cluster geometries rather than the nuclearity. Recent examples of unusual clusters that show unique color/photoluminescence properties and their utilization for stimuli-responsive modules are also presented. © Springer-Verlag 2014.
Sasaki N.,Hokkaido University
Current Pharmaceutical Biotechnology | Year: 2012
Tyrosine (Tyr) sulfation is a common posttranslational modification of secreted proteins or membrane-bound proteins that is implicated in numerous physiological and pathological processes. The Tyr sulfation modifies proteinprotein interactions involved in leukocyte adhesion, homeostasis, and receptor-mediated signaling. To data, 80 Tyrsulfated proteins have been identified. As new methodologies and bioinformatics for the detection of Tyr sulfation become available, the number of Tyr-sulfated acceptor proteins discovered is bound to increase. Further, recent advances in microscopy and fluorescence technology will provide information on the true spatial and temporal nature of Tyr-sulfated proteins within the intact cell. This review summarizes the methods for the detection of Tyr O-sulfation as well as the biological functions of sulfated Tyr. Further, illustrative examples of the impact of Tyr sulfation on the pharmacological properties are presented. © 2012 Bentham Science Publishers.
Yao I.,Hokkaido University
Biology Letters | Year: 2012
In otherwise mutualistic relationships between aphids and ants, attendance by ants often has negative impacts on aphids. For example, in a previous study using traps in the field, the aphid Tuberculatus quercicola, which exhibits mutualistic interactions with ants, showed extremely low dispersal rates, despite having long wings. This study investigates whether components of the flight apparatus (mesonotum length, flight muscle and wings) differ between aphids attended by ants and not attended by ants. Randomized block analysis of variance, using body length as a covariate, showed that ant attendance has a negative influence on aphid flight apparatus. This result indicates that aphids produce honeydew at the expense of resource investment in flight apparatus. Since the dispersal of T. quercicola is limited under ant attendance, the reduction in flight apparatus could precede a decrease in body size. This study also showed that flight apparatus was more developed in aphids under ant-exclusion conditions. This may imply that T. quercicola fly when ants are not available. The maintenance of flight apparatus in T. quercicola might therefore be partly explained by gene flow on the rare occasions that this aphid species disperses. This journal is © 2012 The Royal Society.
Ishii T.,Hokkaido University
Trends in Molecular Medicine | Year: 2015
Genetically modifying eggs, sperm, and zygotes ('germline' modification) can impact on the entire body of the resulting individual and on subsequent generations. With the advent of genome-editing technology, human germline gene modification is no longer theoretical. Owing to increasing concerns about human germline gene modification, a voluntary moratorium on human genome-editing research and/or the clinical application of human germline genome editing has recently been called for. However, whether such research should be suspended or encouraged warrants careful consideration. The present article reviews recent research on mammalian germline genome editing, discusses the importance of public dialogue on the socioethical implications of human germline genome-editing research, and considers the relevant guidelines and legislation in different countries. © 2015 Elsevier Ltd.
Gando S.,Hokkaido University |
Wada H.,Mie University |
Thachil J.,Royal Infirmary
Journal of Thrombosis and Haemostasis | Year: 2013
Two concepts have been proposed for the hemostatic changes occurring early after trauma. Disseminated intravascular coagulation (DIC) with the fibrinolytic phenotype is characterized by activation of the coagulation pathways, insufficient anticoagulant mechanisms and increased fibrinolysis. Coagulopathy of trauma and acute coagulopathy of trauma-shock (COT/ACOTS) occurs as a result of increased activation of the thrombomodulin and protein C pathways, leading to the suppression of coagulation and activation of fibrinolysis. Despite the differences between these two conditions, independent consideration of COT/ACOTS from DIC with the fibrinolytic phenotype is probably incorrect. Robust diagnostic criteria based on its pathophysiology are required to establish COT/ACOTS as a new independent disease concept. In addition, the independency of its characteristics, laboratory data, time courses and prognosis from DIC should be confirmed. Confusion between two concepts may be based on studies of trauma lacking the following: (i) a clear distinction of the properties of blood between the inside and outside of vessels, (ii) a clear distinction between physiologic and pathologic hemostatic changes, (iii) attention to the time courses of the changes in hemostatic parameters, (iv) unification of the study population, and (v) recognition that massive bleeding is not synonymous with coagulation disorders. More information is needed to elucidate the pathogenesis of these two entities, DIC with the fibrinolytic phenotype and COT/ACOTS after trauma. However, available data suggest that COT/ACOTS is not a new concept but a disease entity similar to or the same as DIC with the fibrinolytic phenotype. © 2013 International Society on Thrombosis and Haemostasis.
Mizumoto S.,Meijo University |
Yamada S.,Meijo University |
Sugahara K.,Meijo University |
Sugahara K.,Hokkaido University
Current Opinion in Structural Biology | Year: 2015
Recent functional studies on chondroitin sulfate-dermatan sulfate (CS-DS) demonstrated its indispensable roles in various biological events including brain development and cancer. CS-DS proteoglycans exert their physiological activity through interactions with specific proteins including growth factors, cell surface receptors, and matrix proteins. The characterization of these interactions is essential for regulating the biological functions of CS-DS proteoglycans. Although amino acid sequences on the bioactive proteins required for these interactions have already been elucidated, the specific saccharide sequences involved in the binding of CS-DS to target proteins have not yet been sufficiently identified. In this review, recent findings are described on the interaction between CS-DS and some proteins which are especially involved in the central nervous system and cancer development/metastasis. © 2015.
Amizuka N.,Hokkaido University
Clinical calcium | Year: 2014
In bone, biomineralization induced by osteoblasts is known to be initiated by small extracellular vesicles referred to as "matrix vesicles". Matrix vesicles possess many enzymes and transporters, which synthesize and incorporate Ca2+ and PO4- into the vesicles. Calcification initiates when crystalline calcium phosphates are nucleated inside these matrix vesicles, and calcium phosphates, i.e., hydroxyapatite crystals, grow and eventually break through the membrane to get out of the matrix vesicles. Exposed calcium phosphates featuring "ribbon-like" appearance assemble radially, forming spherical mineralized structure, referred to as "mineralized nodule" or "calcifying globule". This process is called "matrix vesicle mineralization". Thereafter, the mineralized nodules make contacts with surrounding collagen fibrils, extending mineralization along with their longitudinal axis from the contact points of collagen fibrils - collagen mineralization. Matrix vesicle mineralization and subsequent collagen mineralization are classified as primary mineralization associated with osteoblastic bone formation. After primary mineralization, secondary mineralization takes place, gradually increasing mineral density of bone matrix. This review will introduce the microscopic findings on matrix vesicle mineralization and subsequent collagen mineralization.
Hatanaka M.,Kyoto University |
Maeda S.,Hokkaido University |
Morokuma K.,Kyoto University
Journal of Chemical Theory and Computation | Year: 2013
To predict the stereoselectivity of large and flexible reaction systems, structural sampling of many transition states (TSs) is required. We used an automated search method, the artificial force induced reaction (AFIR) method, for TS sampling and found 91 syn- and 73 anti-TSs for the diastereoselective C-C bond formation step of the aqueous lanthanide-catalyzed Mukaiyama aldol reaction. Among them 11 syn- and six anti-TSs are found to contribute significantly to the diastereomeric ratio at room temperature. © 2013 American Chemical Society.
Teshima T.,Hokkaido University |
Reddy P.,University of Michigan |
Zeiser R.,Albert Ludwigs University of Freiburg
Biology of Blood and Marrow Transplantation | Year: 2016
Graft-versus-host disease (GVHD) continues to be a leading cause of morbidity and mortality after allogeneic hematopoietic stem cell transplantation. Recent insights into intestinal homeostasis and uncovering of new pathways and targets have greatly reconciled our understanding of GVHD pathophysiology and will reshape contemporary GVHD prophylaxis and treatment. Gastrointestinal (GI) GVHD is the major cause of mortality. Emerging data indicate that intestinal stem cells (ISCs) and their niche Paneth cells are targeted, resulting in dysregulation of the intestinal homeostasis and microbial ecology. The microbiota and their metabolites shape the immune system and intestinal homeostasis, and they may alter host susceptibility to GVHD. Protection of the ISC niche system and modification of the intestinal microbiota and metabolome to restore intestinal homeostasis may, thus, represent a novel approach to modulate GVHD and infection. Damage to the intestine plays a central role in amplifying systemic GVHD by propagating a proinflammatory cytokine milieu. Molecular targeting to inhibit kinase signaling may be a promising approach to treat GVHD, ideally via targeting the redundant effect of multiple cytokines on immune cells and enterocytes. In this review, we discuss insights on the biology of GI GVHD, interaction of microflora and metabolome with the hosts, identification of potential new target organs, and identification and targeting of novel T cell-signaling pathways. Better understanding of GVHD biology will, thus, pave a way to develop novel treatment strategies with great clinical benefits. © 2016 American Society for Blood and Marrow Transplantation.
Ziemnicka-Sylwester M.,Hokkaido University
Materials and Design | Year: 2014
The TiB2-Cu cermets with predominant concentration of superhard TiB2 (from 45 to 90vol.%) were fabricated using elemental powders by means of SHS (self-propagating high-temperature synthesis) process and simultaneously densified by p-HIP (pseudo-isostatic pressing technique). The heat released during highly exothermic SHS reaction was "in situ" utilized for sintering. The combustion occurred even for 50vol.% Cu dilution. According to XRD metallic copper binder was formed in those cermets in whole range of investigated compositions. The TiB2 volume fraction significantly influenced the properties of fabricated materials, especially grain size and hardness. Both the average grain size and hardness significantly increased with TiB2 content, so the maximum value of 18GPa was measured for TiB2-5vol.%Cu composite. Coarse grains of 6.4μm in size were observed for this composite while TiB2-based submicro-composites were formed for 40-50% of Cu where the average grain size did not exceed 0.6μm. The Vickers hardness of 16-18GPa obtained for cermets containing from 85 to 90vol.% of TiB2 and no radial cracks in Vickers hardness test proved that in term of hardness and fracture toughness the composites might be competitive to WC-Co cermets. © 2013 Elsevier Ltd.
Yamaguchi Y.,Hokkaido University |
Huffaker A.,U.S. Department of Agriculture
Current Opinion in Plant Biology | Year: 2011
Plant defense responses against invading organisms are initiated through the perception of molecules associated with attacking microbes and herbivores by pattern recognition receptors. In addition to elicitor molecules derived from attacking organisms, plants recognize host-derived molecules. These endogenous elicitors induce and amplify the defense responses against invading organisms both locally and systemically. Several classes of plant-derived molecules elicit defense, including cell wall fragments and peptides. Endogenous peptide elicitors have been discovered in species across the plant kingdom, and their role regulating immunity to both herbivores and pathogens is becoming increasingly appreciated. In this review, we will focus on the five known endogenous peptide elicitor families, summarize their properties, and discuss research goals to further understanding of plant innate immunity. © 2011 Elsevier Ltd.
Iwakiri D.,Hokkaido University
Virus Research | Year: 2016
Epstein-Barr Virus (EBV) is known as an oncogenic herpesvirus implicated in the pathogenesis of various malignancies. It has been reported that EBV non-coding RNAs (ncRNAs) including EBV-encoded small RNAs (EBERs) and EBV-miRNAs contribute to viral pathogenesis. EBERs that are expressed abundantly in latently EBV-infected cells have been reported to play significant roles in tumorigenesis by EBV. Furthermore, it was demonstrated that the modulation of host innate immune signals by EBERs contributes to EBV-mediated pathogenesis including oncogenesis. Recently it was demonstrated that EBERs are secreted via exosomes by EBV-infected cells. It was also demonstrated that exosomes contain a number of EBV-encoded miRNAs. Various mRNAs have been identified as targets for regulation by EBV-miRNAs in host cells, therefore, EBERs and EBV-miRNAs might function through the transfer of exosomes. © 2015 Elsevier B.V.
Sakai R.,Hokkaido University |
Swanson G.T.,Northwestern University
Natural Product Reports | Year: 2014
Covering: 1995 to early 2013 This review covers the isolation, chemical structure, biological activity, structure activity relationships including synthesis of chemical probes, and pharmacological characterization of neuroactive marine natural products; 302 references are cited. © 2014 The Royal Society of Chemistry.
Kobayashi Y.,Hokkaido University
The American journal of sports medicine | Year: 2010
BACKGROUND: Concerning meniscal tissue regeneration, many investigators have studied the development of a tissue-engineered meniscus. However, the utility still remains unknown. HYPOTHESIS: Implantation of autogenous meniscal fragments wrapped with a fascia sheath into the donor site meniscal defect may significantly enhance fibrocartilage regeneration in vivo in the defect. STUDY DESIGN: Controlled laboratory study. METHODS: Seventy-five mature rabbits were used in this study. In each animal, an anterior one-third of the right medial meniscus was resected. Then, the animals were divided into the following 3 groups of 25 rabbits each: In group 1, no treatment was applied to the meniscal defect. In group 2, the defect was covered with a fascia sheath. In group 3, after the resected meniscus was fragmented into small pieces, the fragments were grafted into the defect. Then, the defect with the meniscal fragments was covered with a fascia sheath. In each group, 5 rabbits were used for histological evaluation at 3, 6, and 12 weeks after surgery, and 5 rabbits were used for biomechanical evaluation at 6 and 12 weeks after surgery. RESULTS: Histologically, large round cells in group 3 were scattered in the core portion of the meniscus-shaped tissue, and the matrix around these cells was positively stained by safranin O and toluisin blue at 12 weeks. The histological score of group 3 was significantly higher than that of group 1 and group 2. Biomechanically, the maximal load and stiffness of group 3 were significantly greater than those of groups 1 and 2. CONCLUSION: This study clearly demonstrated that implantation of autogenous meniscal fragments wrapped with a fascia sheath into the donor site meniscal defect significantly enhanced fibrocartilage regeneration in vivo in the defect at 12 weeks after implantation in the rabbit. CLINICAL RELEVANCE: This study proposed a novel strategy to treat a large defect after a meniscectomy.
Ohkubo S.,Osaka University |
Ohkubo S.,Kochi University |
Hirabayashi Y.,Hokkaido University
Physical Review C - Nuclear Physics | Year: 2014
Rainbows are generally considered to be caused by static refraction and reflection. A primary and a secondary rainbow appear due to refraction and internal reflection in a raindrop as explained by Newton. The quantum nuclear rainbow, which is generated by refraction in the nucleus droplet, only has a "primary" rainbow. Here we show for the first time evidence for the existence of a secondary nuclear rainbow generated dynamically by coupling to an excited state without internal reflection. This has been demonstrated for experimental O16+C12 scattering using the coupled channel method with an extended double folding potential derived from microscopic realistic wave functions for C12 and O16. © 2014 American Physical Society.
Ogawa H.,Hokkaido University |
Ogawa H.,Japan Science and Technology Agency |
Oka K.,Keio University
Journal of Neuroscience | Year: 2015
Stimulus-specific adaptation (SSA) is considered to be the neural underpinning of habituation to frequent stimuli and novelty detection. However, neither the cellular mechanism underlying SSA nor the link between SSA-like neuronal plasticity and behavioral modulation is well understood. The wind-detection system in crickets is one of the best models for investigating the neural basis of SSA. We found that crickets exhibit stimulus-direction-specific adaptation in wind-elicited avoidance behavior. Repetitive air currents inducing this behavioral adaptation reduced firings to the stimulus and the amplitude of excitatory synaptic potentials in wind-sensitive giant interneurons (GIs) related to the avoidance behavior. Injection of a Ca2+ chelator into GIs diminished both the attenuation of firings and the synaptic depression induced by the repetitive stimulation, suggesting that adaptation of GIs induced by this stimulation results in Ca2+-mediated modulation of postsynaptic responses, including postsynaptic short-term depression. Some types of GIs showed specific adaptation to the direction of repetitive stimuli, resulting in an alteration of their directional tuning curves. The types of GIs for which directional tuning was altered displayed heterogeneous direction selectivity in their Ca2+ dynamics that was restricted to a specific area of dendrites. In contrast, other types of GIs with constant directionality exhibited direction-independent global Ca2+ elevation throughout the dendritic arbor. These results suggest that depression induced by local Ca2+ accumulation at repetitively activated synapses of key neurons underlies direction-specific behavioral adaptation. This input-selective depression mediated by heterogeneous Ca2+ dynamics could confer the ability to detect novelty at the earliest stages of sensory processing in crickets. © 2015 the authors.
Yoshida T.,Hokkaido University
Proceedings - IEEE International Conference on Data Mining, ICDM | Year: 2010
We consider the community detection problem from a partially observable network structure where some edges are not observable. Previous community detection methods are often based solely on the observed connectivity relation and the above situation is not explicitly considered. Even when the connectivity relation is partially observable, if some profile data about the vertices in the network is available, it can be exploited as auxiliary or additional information. We propose to utilize a graph structure (called a profile graph) which is constructed via the profile data, and propose a simple model to utilize both the observable connectivity relation and the profile graph. Furthermore, instead of a hierarchical approach, based the modularity matrix of the network structure, we propose an embedding approach which utilizes the regularization via the profile graph. Various experiments are conducted over a social network data and comparison with several state of the art methods is reported. The results are encouraging and indicate that it is promising to pursue this line of research. © 2010 IEEE.
Eke E.,University of Illinois at Urbana - Champaign |
Parker G.,University of Illinois at Urbana - Champaign |
Shimizu Y.,Hokkaido University
Journal of Geophysical Research: Earth Surface | Year: 2014
Meandering rivers display active communication between bank erosion and bar deposition processes. How does this occur? How does the river select its width? To answer these questions, we implement a model for meander migration where both bank processes (erosion and deposition) are considered independently. Bank erosion is modeled as erosion of purely noncohesive bank material damped by natural slump block armoring; channel deposition is modeled via flow-retarded vegetal encroachment. Both processes are tied to a slope-dependent channel forming Shields number; banks with near-bank Shields number below this value undergo deposition, and those above it undergo erosion. Channel-forming Shields number must increase with slope, as dictated by available data and model performance. Straight channel modeling shows that a channel arrives at an equilibrium width from any initial condition. For the channel bend, the river always approaches an asymptotic state where width reduces slowly in time and where bank erosion and deposition occur at nearly equal rates. Before this state is reached, however, the river follows a phase-plane trajectory with four possible regimes: (a) both banks erode, (b) both banks deposit, (c) both banks migrate outward, but with a faster depositing bank (bar push), and (d) both banks migrate outward, but with a faster eroding bank (bank pull). The trajectory of migration on the phase plane depends on initial conditions and input parameters controlling the rate of depositional and erosional migration. All input parameters have specific physical meaning, and the potential to be measured in the field. ©2014. American Geophysical Union. All Rights Reserved.
Okuyama M.,Hokkaido University
Bioscience, Biotechnology and Biochemistry | Year: 2011
A huge number of glycoside hydrolases are classified into the glycoside hydrolase family (GH family) based on their amino-acid sequence similarity. The glycoside hydrolases acting on α-glucosidic linkage are in GH family 4, 13, 15, 31, 63, 97, and 122. This review deals mainly with findings on GH family 31 and 97 enzymes. Research on two GH family 31 enzymes is described: clarification of the substrate recognition of Escherichia coli α-xylosidase, and glycosynthase derived from Schizosaccharomyces pombe α-glucosidase. GH family 97 is an aberrant GH family, containing inverting and retaining glycoside hydrolases. The inverting enzyme in GH family 97 displays significant similarity to retaining α-glycosidases, including GH family 97 retaining α-glycosidase, but the inverting enzyme has no catalytic nucleophile residue. It appears that a catalytic nucleophile has been eliminated during the molecular evolution in the same way as a man-made nucleophile mutant enzyme, which catalyzes the inverting reaction, as in glycosynthase and chemical rescue.
Ishikawa T.,Hokkaido University
Soils and Foundations | Year: 2010
This paper proposes new testing methods for evaluating the effects of freeze-thaw action on the deformation-strength characteristics and the water retention-permeability characteristics of granular materials under unsaturated conditions. A triaxial apparatus and a permeability apparatus for unsaturated soils, with cooling systems to control the temperature of soil specimens and use the pressure membrane method instead of the pressure plate method, were newly developed in order to examine the hydro-mechanical behavior of unsaturated soils subjected to the freeze-thaw sequence, as experienced by in-situ soils in cold regions. Results indicate that the proposed testing methods with these newly developed test apparatuses are highly useful in the evaluation of the effect of freeze-thaw action on the hydro-mechanical behavior of unsaturated granular materials and in the reduction of total testing time.
Yasui S.,Hokkaido University |
Yasui S.,Japan Meteorological Agency |
Watanabe M.,University of Tokyo
Journal of Climate | Year: 2010
To better understand the predictability of the wavelike circumglobal teleconnection (CGT) pattern prevailing during boreal summer, two sets of experiments are performed using a nonlinear dry atmospheric model. Each experiment consists of a 10-member ensemble of 26-yr integrations driven by the diabatic heating derived from reanalysis data: one with the monthly climatological mean heating (CLIM) and the other with the monthly heating for 1979-2004 (HIST). Both do well in reproducing the observed summer mean state, as well as the low-frequency variance distribution. The CGT pattern identified in the monthly meridional wind anomalies at 200 hPa shows zonally oriented wave packets over Eurasia. The simulatedCGT has a nearly identical phase structure with the observations and indicates little difference between the CLIM and HIST results. While this indicates that the origin of CGT lies in the internal dry dynamics, the ensemble mean of the CGT in HIST is partly controlled by the slow variation in the heating field, as indicated by the high potential predictability of the simulatedCGTpattern. Diagnoses using the linearized model demonstrate that the heating anomaly most responsible for the CGT-like steady response is located over the eastern Mediterranean region, where the heating may be coupled with the CGT pattern. In addition to the heating near the CGT, remote heating and cooling anomalies over North America and equatorial Africa are found to be effective at exciting stationary Rossby waves trapped on the Atlantic and Asian jets. It is thus suggested that the mechanisms generating the heating anomalies over these regions are the key to the predictability of the CGT pattern. © 2010 American Meteorological Society.
Beye F.,Nagoya University |
Kobayashi T.,Hokkaido University |
Kuwakino S.,Chung Yuan Christian University
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2014
We show that non-Abelian discrete symmetries in orbifold string models have a gauge origin. This can be understood when looking at the vicinity of a symmetry enhanced point in moduli space. At such an enhanced point, orbifold fixed points are characterized by an enhanced gauge symmetry. This gauge symmetry can be broken to a discrete subgroup by a nontrivial vacuum expectation value of the Kähler modulus T. Using this mechanism it is shown that the δ(54) non-Abelian discrete symmetry group originates from a SU(3) gauge symmetry, whereas the D4 symmetry group is obtained from a SU(2) gauge symmetry. © 2014 The Authors.
Inomata M.,Asahi University |
Niida S.,National Institute for Longevity science |
Shibata K.-I.,Hokkaido University |
Into T.,Asahi University
Cellular and Molecular Life Sciences | Year: 2012
Toll-like receptor (TLR) signaling is linked to autophagy that facilitates elimination of intracellular pathogens. However, it is largely unknown whether autophagy controls TLR signaling. Here, we report that poly (I: C) stimulation induces selective autophagic degradation of the TLR adaptor molecule TRIF and the signaling molecule TRAF6, which is revealed by gene silencing of the ubiquitin- editing enzyme A20. This type of autophagy induced formation of autophagosomes and could be suppressed by an autophagy inhibitor and lysosomal inhibitors. However, this autophagy was not associated with canonical autophagic processes, including involvement of Beclin-1 and conversion of LC3-I to LC3-II. Through screening of TRIF-interacting 'autophagy receptors' in human cells, we identified that NDP52 mediated the selective autophagic degradation of TRIF and TRAF6 but not TRAF3. NDP52 was polyubiquitinated by TRAF6 and was involved in aggregation of TRAF6, which may result in the selective degradation. Intriguingly, only under the condition of A20 silencing, NDP52 could effectively suppress poly (I: C) - induced proinflammatory gene expression. Thus, this study clarifies a selective autophagic mechanism mediated by NDP52 that works downstream of TRIF-TRAF6. Furthermore, although A20 is known as a signaling fine-tuner to prevent excess TLR signaling, it paradoxically downregulates the fine-tuning effect of NDP52 on TLR signaling. © 2011 Springer Basel AG.
Horiuchi W.,Hokkaido University |
Suzuki Y.,Niigata University |
Physical Review C - Nuclear Physics | Year: 2014
A five-body calculation of 12C+n+n+p+p is performed to take a step towards solving an outstanding problem in nuclear theory: the simultaneous and accurate description of the ground and first excited 0+ states of 16O. The interactions between the constituent particles are chosen consistently with the energies of bound subsystems, especially 12C+n, 12C+p, and the α particle. The five-body dynamics is solved with the stochastic variational method on correlated Gaussian basis functions. No restriction is imposed on the four-nucleon configurations except for the Pauli principle excluding the occupied orbits in 12C. The energies of both the ground and first excited states of 16O are obtained in excellent agreement with experiment. Analysis of the wave functions indicates a spatially localized α-particle-like cluster structure for the excited state and a shell-model-like delocalized structure for the ground state. © 2014 American Physical Society.
Ohkubo S.,Osaka University |
Hirabayashi Y.,Hokkaido University
Physical Review C - Nuclear Physics | Year: 2014
We present evidence for the nuclear ripples superimposed on the Airy structure of the nuclear rainbow, which is similar to the meteorological rainbow. The mechanism of the nuclear ripples is also similar to that of the meteorological rainbow, which is caused by the interference between the externally reflective waves and refractive waves. The nuclear ripple structure was confirmed by analyzing the elastic angular distribution in O16+C12 rainbow scattering at EL=115.9 MeV using the coupled channels method by taking account of coupling to the excited states of C12 and O16 with a double folding model derived from a density-dependent effective nucleon-nucleon force with realistic wave functions for C12 and O16. The coupling to the excited states plays the role of creating the external reflection. © 2014 American Physical Society.
Bartlem D.G.,Hokkaido University |
Bartlem D.G.,Murdoch University |
Jones M.G.K.,Murdoch University |
Hammes U.Z.,University of Regensburg
Journal of Experimental Botany | Year: 2014
Plants are constantly challenged by pathogens and pests, which can have a profound impact on the yield and quality of produce in agricultural systems. The vascular system of higher plants is critical for growth and for their ability to counteract changing external conditions, serving as a distribution network for water, nutrients, and photosynthates from the source organs to regions where they are in demand. Unfortunately, these features also make it an attractive target for pathogens and pests that demand access to a reliable supply of host resources. The vascular tissue of plants therefore often plays a central role in pathogen and parasite interactions. One of the more striking rearrangements of the host vascular system occurs during root-knot nematode infestation of plant roots. These sedentary endoparasites induce permanent feeding sites that are comprised of 'giant cells' and are subject to extensive changes in vascularization, resulting in the giant cells being encaged within a network of de novo formed xylem and phloem cells. Despite being considered critical to the function of the feeding site, the mechanisms underlying this vascularization have received surprisingly little attention when compared with the amount of research on giant cell development and function. An overview of the current knowledge on vascularization of root-knot nematode feeding sites is provided here and recent advances in our understanding of the transport mechanisms involved in nutrient delivery to these parasite-induced sinks are described. © 2013 The Author.
Taguchi S.,Hokkaido University
Polymer Degradation and Stability | Year: 2010
Polylactic acid (PLA), a representative bio-based polyester, has been commonly synthesized via a multi-step by chemical process. The current modes of generating PLA involve microbial fermentation of starting material, lactic acid (LA), followed by chemical ring-opening polymerization. Recently, one-pot complete bioprocess for LA-based polyesters has been established as a microbial cell factory (MCF). The concept is a process conversion from the usual chemical factory to the MCF. This new challenge was triggered by discovery of an engineered LA-polymerizing enzyme (LPE). The LPE was found as one of the members of an extensive mutant library that has been created through the long-term evolutionary engineering study of natural biopolyester-synthesizing enzymes. Needless to say, a strategic method of getting the beneficial mutation in the enzyme is of the utmost importance and an essential step towards accomplishing the desired purpose, the acquisition of the LA-polymerizing activity in this case. In this review, the structures and properties of LPE-catalyzed polymerization products will be discussed as well as backgrounds on establishment of the MCFs for synthesis of LA-based polyesters. Also, experimental strategies for enrichment of the LA fraction will be proposed to further advance the prototype of MCF based on the related metabolic pathways. © 2010 Elsevier Ltd. All rights reserved.
Fusetani N.,Hokkaido University
Pure and Applied Chemistry | Year: 2010
The number of marine natural products (MNPs) that have been applied to biotechnological industry is very limited, although nearly 20 000 new compounds were discovered from marine organisms since the birth of MNPs in the early 1970s. However, it is apparent that they have a significant potential as pharmaceuticals, cosmetics, nutraceuticals, research tools, and others. This article focuses on selective antitumor metabolites isolated from marine sponges and tunicates and their modes of action, as well as promising candidates for nontoxic antifoulants discovered from marine organisms. © 2010 IUPAC.
Nihashi S.,Hokkaido University of Science |
Ohshima K.I.,Hokkaido University
Journal of Climate | Year: 2015
Sinking of dense water from Antarctic coastal polynyas produces Antarctic Bottom Water (AABW), which is the densest water in the global overturning circulation and is a key player in climate change as a significant sink for heat and carbon dioxide. Very recent studies have suggested that landfast sea ice (fast ice) plays an important role in the formation and variability of the polynyas and possibly AABW. However, they have been limited to regional and case investigations only. This study provides the first coincident circumpolar mapping of Antarctic coastal polynyas and fast ice. The map reveals that most of the polynyas are formed on the western side of fast ice, indicating an important role of fast ice in the polynya formation. Winds diverging from a boundary comprising both coastline and fast ice are the primary determinant of polynya formation. The blocking effect of fast ice on westward sea ice advection by the coastal current would be another key factor. These effects on the variability in sea ice production for 13 major polynyas are evaluated quantitatively. Furthermore, it is demonstrated that a drastic change in fast ice extent, which is particularly vulnerable to climate change, causes dramatic changes in the polynyas and possibly AABW formation that can potentially contribute to further climate change. These results suggest that fast ice and precise polynya processes should be addressed by next-generation models to produce more accurate climate projections. This study provides the boundary and validation data of fast ice and sea ice production for such models. © 2015 American Meteorological Society.
Nakanishi M.,University of Tennessee at Knoxville |
Nozaki R.,Hokkaido University
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2011
A simplified model of a hydrogen-bonding network is proposed in order to clarify the microscopic structure of the cooperative rearranging region (CRR) in Adam-Gibbs theory. Our model can be solved analytically, and it successfully explains the reported systematic features of the glass transition of polyhydric alcohols. In this model, hydrogen bonding is formulated based on binding free energy. Assuming a cluster of molecules connected by double hydrogen bonds is a CRR and approximating the hydrogen-bonding network as a Bethe lattice in percolation theory, the temperature dependence of the structural relaxation time can be obtained analytically. Reported data on relaxation times are well described by the obtained equation. By taking the lower limit of the binding free energy with this equation, the Vogel-Fulcher-Tammann equation can be derived. Consequently, the fragility index and glass transition temperature can be expressed as functions of the number of OH groups in a molecule, and this relation agrees well with the reported experimental data. © 2011 American Physical Society.
Hara S.,Hokkaido University
Topics in Current Chemistry | Year: 2012
Recent developments in the stereoselective synthesis of fluoroalkenes, which include hydrofluorination of alkyne, fluorination of alkenylmetal, condensation methods, dehydrofluorination of gem-difluoro compounds, and a cross-coupling reaction using fluorohaloalkenes or fluoroalkenylmetal, are described in this chapter. © 2012 Springer-Verlag Berlin Heidelberg.
Sasaki K.,Hokkaido University |
Takada N.,Nagoya University
Pure and Applied Chemistry | Year: 2010
The irradiation of an intense laser pulse onto a solid target immersed in liquid produces dense plasma. The plasma produced by liquid-phase laser ablation has unique features at high pressure and temperature, which are never realized by liquid-phase discharges. Another unique characteristic of liquid-phase laser ablation is the formation of a cavitation bubble. This article reports the fundamental aspects of liquid-phase laser-ablation plasmas, cavitation bubbles, and the formation processes of nanoparticles, together with some applications of liquid-phase laser ablation. © 2010 IUPAC.
Kawai T.,Hokkaido University
Zootaxa | Year: 2013
The Indo-Pacific peristediid genus Satyrichthys Kaup, 1873 was first diagnosed as having a broad head with mesethmoid, postocular, parietal and preopercular spines. Later, most ichthyologists characterized Satyrichthys by its toothless jaws and strong preopercular spine. Kawai (2008) divided Satyrichthys into two genera, Satyrichthys and Scalicus, on the basis of a phylogenetic hypothesis, and redefined Satyrichthys. Seven species of Satyrichthys are recognized here, including one new species: S. clavilapis, S. laticeps, S. longiceps, S. milleri sp. nov., S. moluccensis, S. rieffeli and S. welchi. The new species is distinguished from its congeners in having equilateral-triangular rostral projections, 4 lip and 4 chin barbels, and no anterior directed spines on the upper lateral row of the caudal peduncle. Satyrichthys laticeps, previously treated as a junior synonym of S. moluccensis, is regarded as a valid species. The following new synonyms are noted: S. adeni, S. halyi and S. magnus are all junior synonyms of S. laticeps; S. isokawae is a junior synonym of S. moluccensis; and S. lingi is a junior synonym of S. welchi. In addition, a neotype is designated for S. moluccensis. Copyright © 2013 Magnolia Press.
Miyazaki Y.,Hokkaido University |
Miyazaki Y.,Okayama University
Ecological Research | Year: 2013
Several proximate factors of masting have been provided. Here, I focus on the role of internal factors, especially the relationship between internal carbon resources and modular structures in trees. I summarize various studies of carbon resource allocation for reproduction during masting events in terms of the proximate factors of masting and discuss the modular structure in which trees accumulate and consume carbon resources as well as the timing when internal carbon resources affect masting since trees have complex resource dynamics among organs. The resource budget model, which provides a simple mechanistic explanation of the masting mechanism, is supported by various study lines. This model assumes decreasing levels of stored photosynthate after flowering and fruiting. According to several studies, however, carbon reserves do not decrease after fruiting in species in which the modules autonomously allocate current photosynthate for fruiting. In addition, it is important to elucidate when carbon resources affect masting events because during their long developmental processes, trees pass through various stages until they produce maturing fruits to create successful masting events. To explore the mechanisms of masting in future studies, it would be important to figure out how and when candidate factors (including nutrients other than carbon) may influence the entire reproduction process, for example, using field manipulation experiments. © 2011 The Ecological Society of Japan.
Tachikawa H.,Hokkaido University
ChemPhysChem | Year: 2014
The mechanism of dissolution of the Li+ ion in an electrolytic solvent is investigated by the direct ab initio molecular dynamics (AIMD) method. Lithium fluoroborate (Li+BF4-) and ethylene carbonate (EC) are examined as the origin of the Li+ ion and the solvent molecule, respectively. This salt is widely utilized as the electrolyte in the lithium ion secondary battery. The binding of EC to the Li+ moiety of the Li+BF4- salt is exothermic, and the binding energies at the CAM-B3LYP/6-311++G(d,p) level for n=1, 2, 3, and 4, where n is the number of EC molecules binding to the Li + ion, (EC)n(Li+BF4-), are calculated to be 91.5, 89.8, 87.2, and 84.0 kcal-mol-1 (per EC molecule), respectively. The intermolecular distances between Li+ and the F atom of BF4- are elongated: 1.773 Å (n=0), 1.820 Å (n=1), 1.974 Å (n=2), 1.942 Å (n=3), and 4.156 Å (n=4). The atomic bond populations between Li+ and the F atom for n=0, 1, 2, 3, and 4 are 0.202, 0.186, 0.150, 0.038, and 0.0, respectively. These results indicate that the interaction of Li+ with BF 4- becomes weaker as the number of EC molecules is increased. The direct AIMD calculation for n=4 shows that EC reacts spontaneously with (EC)3(Li+BF4-) and the Li+ ion is stripped from the salt. The following substitution reaction takes place: EC+(EC)3(Li+BF4 -)→(EC)4Li+-(BF4-). The reaction mechanism is discussed on the basis of the theoretical results. Real-time solvation of Li+: The mechanism of dissolution of the Li+ ion in an electrolytic solvent is investigated by the direct ab initio molecular dynamics method. Lithium fluoroborate (Li+BF 4-) and ethylene carbonate are examined as the origin of the Li+ ion and the solvent molecule, respectively. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Kimura T.,Hokkaido University
Oncogene | Year: 2015
Synovial sarcoma accounts for almost 10% of all soft tissue sarcomas, and its prognosis is poor with 5-year survival rates at 36%. Thus, new treatments and therapeutic targets for synovial sarcoma are required. Tumor-initiating cells have been defined by the ability for self-renewal and multipotent differentiation, and they exhibit higher tumorigenic capacity, chemoresistance and radiation resistance, expecting to be a new therapeutic target. In synovial sarcoma, the presence of such stemness remains largely unclear; thus, we analyzed whether synovial sarcoma possessed tumor-initiating cells and explored specific markers, and we discovered that synovial sarcoma cell lines possessed heterogeneity by way of containing a sphere-forming subpopulation highly expressing NANOG, OCT4 and SOX2. By expression microarray analysis, CXCR4 was identified to be highly expressed in the sphere subpopulation and correlated with stem-cell-associated markers. Inhibition of CXCR4 suppressed the cell proliferation of synovial sarcoma cell lines in vitro. The tumor-initiating ability of CXCR4-positive cells was demonstrated by xenograft propagation assay. CXCR4-positive cells showed higher tumorigenicity than negative ones and possessed both self-renewal and multipotent differentiation ability. Immunohistochemical analysis of 39 specimens of synovial sarcoma patients revealed that CXCR4 strongly correlated with poor prognosis of synovial sarcoma. Thus, we conclude that CXCR4 is the marker of synovial sarcoma-initiating cells, a new biomarker for prognosis and a new potential therapeutic target.Oncogene advance online publication, 7 December 2015; doi:10.1038/onc.2015.461. © 2015 Macmillan Publishers Limited
Koper M.T.M.,Leiden University |
Koper M.T.M.,Hokkaido University
Journal of Solid State Electrochemistry | Year: 2013
This paper discusses the concepts of rate-determining step and potential-determining step in the context of electrocatalytic reaction schemes, illustrates how the simpler concept of potential-determining step often captures the essence of a bottleneck in a reaction scheme, and thereby provides straightforward hints for developing better catalysts. © 2012 Springer-Verlag Berlin Heidelberg.
McElroy S.P.,University of Dundee |
Nomura T.,Hokkaido University |
Torrie L.S.,University of Dundee |
Warbrick E.,University of Dundee |
And 3 more authors.
PLoS Biology | Year: 2013
The drug molecule PTC124 (Ataluren) has been described as a read-through agent, capable of suppressing premature termination codons (PTCs) and restoring functional protein production from genes disrupted by nonsense mutations. Following the discovery of PTC124 there was some controversy regarding its mechanism of action with two reports attributing its activity to an off-target effect on the Firefly luciferase (FLuc) reporter used in the development of the molecule. Despite questions remaining as to its mechanism of action, development of PTC124 continued into the clinic and it is being actively pursued as a potential nonsense mutation therapy. To thoroughly test the ability of PTC124 to read through nonsense mutations, we conducted a detailed assessment comparing the efficacy of PTC124 with the classical aminoglycoside antibiotic read-through agent geneticin (G418) across a diverse range of in vitro reporter assays. We can confirm the off-target FLuc activity of PTC124 but found that, while G418 exhibits varying activity in every read-through assay, there is no evidence of activity for PTC124. © 2013 McElroy et al.
Tai-Nagara I.,Keio University |
Matsuoka S.,Keio University |
Ariga H.,Hokkaido University |
Suda T.,Keio University
Blood | Year: 2014
Hematopoietic stem cells (HSCs) maintain stemness through various mechanisms that protectagainststressfulconditions. Heatshock proteins(HSPs) preservecellhomeostasis during stress responses through protein quality control, suggesting that HSPs may safeguard HSCs against numerous traumas. Here, we show that mortalin, a mitochondrial HSP, plays an essential role in maintaining HSC properties by regulating oxidative stress. Mortalin is primarily localized in hematopoietic stem and progenitor cell (HSPC) compartments. In this study, the inhibition of mortalin function caused abnormal reactive oxygen species (ROS) elevation in HSCs and reduced HSC numbers. Knockdown (KD) of mortalin in HSPCs impaired their ability to repopulate and form colonies. Moreover, mortalin-KD HSCs could not maintain quiescence and showed severe downregulation of cyclin-dependent kinase inhibitor- and antioxidant-related genes. Conversely, HSCs that overexpressed mortalin maintained a high reconstitution capacity and low ROS levels. Furthermore, DJ-1, one of the genes responsible for Parkinson's disease, directly bound to mortalin and acted as a negative ROS regulator. Using DJ-1-deficient mice, we demonstrated that mortalin and DJ-1 coordinately maintain normal ROS levels and HSC numbers. Collectively, these results indicate that the mortalin/DJ-1 complex guards against mitochondrial oxidative stress and is indispensable for the maintenance of HSCs. © 2014 by The American Society of Hematology.
Ma S.S.K.,University of Tokyo |
Maeda K.,University of Tokyo |
Maeda K.,Japan Science and Technology Agency |
Abe R.,Hokkaido University |
Domen K.,University of Tokyo
Energy and Environmental Science | Year: 2012
Tungsten trioxide (WO3) powder was studied as a photocatalyst for water oxidation under visible light (λ > 420 nm). WO3 modified with nanoparticulate Pt species (more specifically, PtOx) as cocatalysts is capable of photocatalyzing water oxidation under visible light in the presence of iodate (IO3-) ions as an electron acceptor under near-neutral pH conditions (pH ≈ 5.9). When PtO x/WO3 was further modified with a very small amount (0.001 wt%) of a metal oxide (e.g., MnOx, CoOx, RuO2 or IrO2) as a secondary cocatalyst, the water oxidation activity was improved. Among the metal oxide cocatalysts examined, RuO2 was found to give the highest performance, with an apparent quantum yield of 14.4% at 420 nm. The results of photocatalytic reactions and photoelectrochemical analyses suggest that the main roles of the loaded PtOx and RuO2 on WO3 are to promote the reduction of IO3- and water oxidation, respectively. This journal is © The Royal Society of Chemistry 2012.
Lee Y.-N.,Korea Institute of Geoscience and Mineral Resources |
Barsbold R.,Mongolian Academy of science |
Currie P.J.,University of Alberta |
Kobayashi Y.,Hokkaido University |
And 4 more authors.
Nature | Year: 2014
The holotype of Deinocheirus mirificus was collected by the 1965 Polish-Mongolian Palaeontological Expedition at Altan Uul III in the southern Gobi of Mongolia. Because the holotype consists mostly of giant forelimbs (2.4 m in length) with scapulocoracoids, for almost 50 years Deinocheirus has remained one of the most mysterious dinosaurs. The mosaic of ornithomimosaur and non-ornithomimosaur characters in the holotype has made it difficult to resolve the phylogenetic status of Deinocheirus. Here we describe two new specimens of Deinocheirus that were discovered in the Nemegt Formation of Altan Uul IV in 2006 and Bugiin Tsav in 2009. The Bugiin Tsav specimen (MPC-D 100/127) includes a left forelimb clearly identifiable as Deinocheirus and is 6% longer than the holotype. The Altan Uul IV specimen (MPC-D 100/128) is approximately 74% the size of MPC-D 100/127. Cladistic analysis indicates that Deinocheirus is the largest member of the Ornithomimosauria; however, it has many unique skeletal features unknown in other ornithomimosaurs, indicating that Deinocheirus was a heavily built, non-cursorial animal with an elongate snout, a deep jaw, tall neural spines, a pygostyle, a U-shaped furcula, an expanded pelvis for strong muscle attachments, a relatively short hind limb and broad-tipped pedal unguals. Ecomorphological features in the skull, more than a thousand gastroliths, and stomach contents (fish remains) suggest that Deinocheirus was a megaomnivore that lived in mesic environments. © 2014 Macmillan Publishers Limited. All rights reserved.
Ishikawa A.,RIKEN |
Tanaka T.,RIKEN |
Tanaka T.,Hokkaido University
Applied Physics Letters | Year: 2013
Plasmon hybridization in a stacked pair of graphene ribbons is investigated at terahertz frequencies. We fabricated and characterized an array of graphene ribbons on a heavily-doped Si substrate with a SiO2 gap layer in between. The interaction between graphene plasmons and their mirror images in the substrate forms a coupled system, mimicking a graphene ribbon pair, thereby dramatically modifies the mode profiles and resultant spectral responses. Magnetic plasmon resonances arising from the plasmon hybridization are demonstrated at terahertz frequencies. The corresponding numerical simulations reveal the important resonant behavior of structured graphene and their hybridized systems. © 2013 AIP Publishing LLC.
Park J.J.,Yonsei University |
Lee K.J.B.,Ewha Womans University |
Wright O.B.,Hokkaido University |
Jung M.K.,Yonsei University |
Lee S.H.,Yonsei University
Physical Review Letters | Year: 2013
We demonstrate 97%, 89%, and 76% transmission of sound amplitude in air through walls perforated with subwavelength holes of areal coverage fractions 0.10, 0.03, and 0.01, respectively, producing 94-, 950-, and 5700-fold intensity enhancements therein. This remarkable level of extraordinary acoustic transmission is achieved with thin tensioned circular membranes, making the mass of the air in the holes effectively vanish. Imaging the pressure field confirms incident-angle independent transmission, thus realizing a bona fide invisible wall. Applications include high-resolution acoustic sensing. © 2013 American Physical Society.
Takahashi T.,Hokkaido University
Neuroendocrinology Letters | Year: 2012
Criminal behaviors have been associated with risk, time and social preferences in economics (Becker 1968; Davis 1988), criminology (Chamlin & Cochran 1997), and neurolaw (Goodenough & Tucker 2010). This study proposes a molecular neuroeconomic framework for the investigation into crime and punishment. Neuroeconomic parameters (e.g., risk-attitude, probability weighting, time discounting in intertemporal choice, loss aversion, and social discounting) are predicted to be related to criminal behavior. Neurobiological and neuroendocrinological substrates such as serotonin, dopamine, norepinephrine, cortisol (a stress hormone), sex hormones (e.g., testosterone), and oxytocin in brain regions such as the orbitofrontal cortex, the amygdala, and the cingulate may be related to the neuroeconomic parameters governing criminal behaviors. The present framework may help us develop "neurolaw" based on molecular neuroeconomics of criminal and antisocial decision-making processes. © 2012 Neuroendocrinology Letters.
Seya T.,Hokkaido University
Cell Host and Microbe | Year: 2014
During viral infection, RIG-I-like receptors (RLRs) are activated upon dephosphorylation by the phosphatase PP1, resulting in type I interferon production. In this issue, Davis et al. (2014) and Mesman et al. (2014) show that measles virus inhibits this antiviral response by targeting PP1 and thus preventing RLR dephosphorylation and activation. © 2014 Elsevier Inc.
Asakura K.,Hokkaido University
Catalysis Today | Year: 2010
Developments in surface science have provided atomic-scale surface images and helped us to understand surface reactions at an atomic-scale. Two big gaps, the pressure gap and material gap, were believed to exist between real catalyst systems and surface science targets; however, they are now being filled. Nonlinear optical phenomenon of sum-frequency generation, glancing-angle X-ray, and scanning probe techniques have been developed as ambient pressure surface analysis methods. Great efforts have made it possible to perform X-ray photoelectron spectroscopy measurements in the presence of gas-phase reactants. Recent improvements in surface analysis techniques for nonconducting targets enable us to investigate metal clusters on well-defined oxide surfaces to fill the material gap. We are now able to initiate and control the surface reactions artificially by adjusting physical parameters. Surface science has reached a new stage not only for determining the surface structures, electronic properties, and reaction mechanisms but also for synthesizing highly active surfaces and controlling catalytic reactions artificially. © 2010 Elsevier B.V. All rights reserved.
Kubo T.,Hokkaido University
Current Genetics | Year: 2010
An increase in the unspliced cox2 transcript and accompanying decrease in the frequency of RNA editing near the exon/intron junction (intron binding site 1, IBS1) have been reported in cold-treated wheat. Here, an attempt was made to clarify whether a similar phenomenon occurs in rice. Levels of unspliced cox2 transcript increased and its editing at the IBS was abolished after cold treatment. The accumulation of COXII protein remained unaffected. The accumulation of intron-containing transcripts of another eight mitochondrial genes, 23 introns in total, was analyzed by Northern blotting and semi-quantitative RT-PCR. An increase in 14 of the 23 intron-adjoining cDNA after cold treatment was observed. Six RNA editing sites in the IBS of four genes were tested as to their status by sequencing cDNA. One of these sites in the nad7 transcript showed a close association with splicing, with editing and splicing occurring simultaneously, irrespective of cold treatment. Two other sites in the intron-containing cox2 and rps3 transcripts were sensitive to cold, where editing frequency began to decrease 1 day after cold treatment, and finally exhibited a tight association with splicing 14 days later. The other sites were efficiently edited. The intron-spliced transcripts were fully edited at all six sites. © 2010 Springer-Verlag.
Yamaura Y.,Hokkaido University
Ornithological Science | Year: 2013
Binomial mixture models (BMMs) have been increasingly applied to account for imperfect detection and to estimate abundance from count data, but their performance has not been thoroughly evaluated. Here, I conducted simulation experiments to examine parameter estimates in BMMs under various situations. I generated data by assuming that abundance followed a Poisson distribution with an expected value λ and that the number of detected individuals followed a binomial distribution with an individual detection probability p. In simple simulations without covariates for λ and p, when the number of sampling sites (n) was between 20 and 160, BMMs could recover λ and p under the following conditions: 0.1≤λ≤160 and p≥0.1. However, within these ranges of λ and p, the estimates were variable under lower values of λ and p, although the situation improved as n increased. When λ and p are expected to exceed these ranges and the sample size is small, the results suggest that sampling and/or modeling designs should be reconsidered. I then conducted simulation experiments with covariates. I assumed that λ increased with a covariate (x) across 20 sampling sites. I varied p, number of visits (v), and their dependency on a covariate. To compare BMMs with analyses that did not accommodate imperfect detection, I fitted ordinary Poisson generalized linear models to mean and maximum counts (GLMmean and GLMmax). The results showed that GLMmax was superior to GLMmean because GLMmean underestimated λ when p was small. GLMmax underestimated a coefficient of the covariate (slope) when v was negatively correlated with x. BMMs successfully recovered true values of the intercepts, slopes, and λ in most cases. However, when p and v were small, and when p and λ were highly negatively correlated due to their inverse dependency on x, estimates from BMMs were more variable. © The Ornithological Societyof Japan 2013.
Akiyama M.,Hokkaido University
Human Mutation | Year: 2010
Mutations in ABCA12 have been described in autosomal recessive congenital ichthyoses (ARCI) including harlequin ichthyosis (HI), congenital ichthyosiform erythroderma (CIE), and lamellar ichthyosis (LI). HI shows the most severe phenotype. CIE and LI are clinically characterized by fine, whitish scales on a background of erythematous skin, and large, thick, dark scales over the entire body without serious background erythroderma, respectively. To date, a total of 56 ABCA12 mutations have been reported in 66 ARCI families including 48 HI, 10 LI, and 8 CIE families of African, European, Pakistani/Indian, and Japanese origin (online database: ). A total of 62.5% of reported ABCA12 mutations are expected to lead to truncated proteins. Most mutations in HI are truncation mutations and homozygous or compound heterozygous truncation mutations always results in HI phenotype. In CIE families, at least one mutation on each allele is typically a missense mutation. Combinations of missense mutations in the first ATP-binding cassette of ABCA12 underlie the LI phenotype. ABCA12 is a keratinocyte lipid transporter associated with lipid transport in lamellar granules, and loss of ABCA12 function leads to a defective lipid barrier in the stratum corneum, resulting in an ichthyotic phenotype. Recent work using mouse models confirmed ABCA12 roles in skin barrier formation. © 2010 Wiley-Liss, Inc.
Hisanaga T.,Nara Institute of Science and Technology |
Kawade K.,Hokkaido University |
Tsukaya H.,University of Tokyo
Journal of Experimental Botany | Year: 2015
Leaves are ideal model systems to study the organ size regulation of multicellular plants. Leaf cell number and cell size are determinant factors of leaf size which is controlled through cell proliferation and post-mitotic cell expansion, respectively. To achieve a proper leaf size, cell proliferation and post-mitotic cell expansion should be co-ordinated during leaf morphogenesis. Compensation, which is enhanced post-mitotic cell expansion associated with a decrease in cell number during lateral organ development, is suggestive of such co-ordination. Genetic and kinematic studies revealed at least three classes of modes of compensation, indicating that compensation is a heterogeneous phenomenon. Recent studies have increased our understanding about the molecular basis of compensation by identifying the causal genes of each compensation-exhibiting mutant. Furthermore, analyses using chimeric leaves revealed that a type of compensated cell expansion requires cell-to-cell communication. Information from recent advances in molecular and genetic studies on compensation has been integrated here and its role in organ size regulation is discussed. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved.
Cheon T.,Kochi University of Technology |
Takahashi T.,Hokkaido University
Physics Letters, Section A: General, Atomic and Solid State Physics | Year: 2010
The quantum decision theory is examined in its simplest form of two-condition two-choice setting. A set of inequalities to be satisfied by any quantum conditional probability describing the decision process is derived. Experimental data indicating the breakdown of classical explanations are critically examined with quantum theory using the full set of quantum phases. © 2010 Elsevier B.V.
Yoneshiro T.,Hokkaido University |
Saito M.,Tenshi College
Current Opinion in Clinical Nutrition and Metabolic Care | Year: 2013
PURPOSE OF REVIEW: Cold exposure activates brown adipose tissue (BAT), the major site of sympathetically activated nonshivering thermognenesis, via transient receptor potential (TRP) channels. Capsaicin and its nonpungent analogue (capsinoids) are agonists for a vanilloid subtype one of TRP, and have the potential to increase whole-body energy expenditure and reduce body fat. This article reviews the regulatory roles of BAT for energy expenditure and body fat in humans, particularly focusing on food ingredients activating the TRP-BAT axis. RECENT FINDINGS: Acute cold exposure increased energy expenditure in humans with metabolically active BAT, but not those without it. Quite similar responses were found after a single oral ingestion of either capsinoids or an alcohol extract of Guinea pepper seeds, indicating that these food ingredients activate BAT and thereby increase energy expenditure. When individuals without active BAT were exposed to cold every day for 6 weeks, BAT was recruited in association with increased energy expenditure and decreased body fat. A 6-week daily ingestion of capsinoids mimicked the effects of repeated cold exposure. These findings indicate that human BAT can be reactivated/recruited, thereby increasing energy expenditure and decreasing body fat. SUMMARY: Human BAT recruited by prolonged ingestion of a vanilloid subtype one of TRP agonists increases energy expenditure and decreases body fat. In addition to capsinoids, there are numerous food ingredients acting as TRP agonists, which are expected to activate BAT and so be useful for the prevention of obesity in daily life. © 2013 Wolters Kluwer Health / Lippincott Williams & Wilkins.
Penati B.,Hokkaido University
Central Asian Survey | Year: 2010
This article deals with rain-fed tilled land (bahārī) and wasteland in Russian Turkestan. On the basis of archival and published sources, the numerous twists and turns of Russian surveying policies before and after the endorsement of the 1886 Turkestan Statute are shown, and problems posed by the specific, mutable nature of bahārī land to the mechanism of land-tax allotment within each rural community, in particular for nonresident households are focused on. The 1900 amendments to the Statute radically changed the way land-tax was raised on bahārī land: thereafter it was to be calculated on the basis of its surface area instead of as a share of the harvest. Moreover, provisions passed in 1900, but fully implemented only in 1908, extended fiscal liability to wasteland whence villagers could earn an income through grazing, collecting firewood and other activities. It is demonstrated that these measures brought about a significant expansion in fiscal revenues, thus helping to narrow and ultimately redress the deficit in the Turkestan krai's primary budget, which had been a persistent problem since the region was originally annexed in 1865. © 2010 Central Asian Survey.
Cuesta A.,Institute Quimica Fisica Rocasolano |
Cabello G.,Institute Quimica Fisica Rocasolano |
Osawa M.,Hokkaido University |
Gutierrez C.,Institute Quimica Fisica Rocasolano
ACS Catalysis | Year: 2012
We present a detailed spectrokinetic study of the electrocatalytic oxidation of formic acid on Au and Pt electrodes using ATR-SEIRAS that has allowed us to unveil the mechanisms of both the direct (in which adsorbed CO is not involved) and the indirect (through adsorbed CO) paths of the reaction with unprecedented detail. Au electrodes were used to study the mechanism of the direct path without the interference of the indirect path, and the observed quadratic dependence of the reaction rate on the formate coverage was then shown to apply also to Pt. The direct path consists of three steps, namely, (i) the electroadsorption of formate (corresponding to the first electron transfer), (ii) the purely chemical bimolecular decomposition of adsorbed formate, and (iii) the second electron transfer. The dehydration of HCOOH to adsorbed CO, that is then oxidized to CO 2 in the indirect path, was studied on Pt at E < 0.4 V vs the reversible hydrogen electrode (RHE), at which potentials the dehydration reaction is the only one taking place on the Pt surface. Our results show that adsorbed formate is also the intermediate in the dehydration of formic acid to adsorbed CO and is, hence, the key intermediate in the electrocatalytic oxidation of formic acid on metals. © 2012 American Chemical Society.
Hatakeyama S.,Hokkaido University
Nature Reviews Cancer | Year: 2011
Emerging clinical evidence shows that the deregulation of ubiquitin-mediated degradation of oncogene products or tumour suppressors is likely to be involved in the aetiology of carcinomas and leukaemias. Recent studies have indicated that some members of the tripartite motif (TRIM) proteins (one of the subfamilies of the RING type E3 ubiquitin ligases) function as important regulators for carcinogenesis. This Review focuses on TRIM proteins that are involved in tumour development and progression. © 2011 Macmillan Publishers Limited. All rights reserved.
Vynnycky M.,University of Limerick |
Maeno N.,Hokkaido University
International Journal of Heat and Mass Transfer | Year: 2012
The Mpemba effect is popularly summarized by the statement that "hot water can freeze faster than cold", and has been observed experimentally since the time of Aristotle; however, there exist almost no theoretical models that predict the effect. This paper considers experimentally and theoretically the cooling of a circular pool of water. A model is derived that takes into account conduction, natural convection, evaporation and thermal radiation. The governing equations are nondimensionalized and asymptotically reduced to yield a one-dimensional moving boundary problem that is solved numerically. Whilst the model may need some refinement in the future, the preliminary results are encouraging, indicating that it can predict the occurrence of the Mpemba effect. © 2012 Elsevier Ltd. All rights reserved.
Sakashita H.,Hokkaido University
International Journal of Heat and Mass Transfer | Year: 2012
This study investigated the saturated pool boiling of water on a 12 mm diameter horizontal heating surface coated with titanium oxide (TiO 2) nanoparticles under atmospheric pressure. The TiO 2 coated surface was formed during nucleate boiling of TiO 2-water-surfactant nanofluid on the plain heating surface at high heat flux conditions. It was found that the CHF of water boiling on the TiO 2 coated surface increased up to about 1.8 times the CHF for the uncoated (plain) surface. To examine the mechanism of the CHF enhancement by TiO 2 nanoparticle coating, liquid-vapor behaviors close to the heating surface were measured using a conductance probe with a tip diameter smaller than 5 lm. The probe signals and the void fraction distributions showed that there is little difference in the liquid-vapor structure in the boiling on the uncoated surface and on the TiO 2 coated surface, that a liquid rich layer (a so called macrolayer) remains on the heating surface, and that in boiling on the TiO 2 coated surface it does not dry out even at heat fluxes far higher than the CHF of the uncoated surface. The thickness of the macrolayer formed beneath large vapor masses was determined from the location where the probe signals corresponding to the large vapor masses disappear. It was found that the macrolayers formed on the TiO 2 coated surface are thicker than those on the uncoated surface, and it is considered that this is the most likely to be a cause of the CHF enhancement with the TiO 2 coated heating surface. © 2012 Elsevier Ltd. All rights reserved.
Takahashi T.,Hokkaido University
Neuroendocrinology Letters | Year: 2011
Suicidal behavior is a leading cause of injury and death worldwide. Suicide has been associated with psychiatric illnesses such as depression and schizophrenia, as well as economic uncertainty, and social/cultural factors. This study proposes a neuroeconomic framework of suicide. Neuroeconomic parameters (e.g., risk-attitude, probability weighting, time discounting in intertemporal choice, and loss aversion) are predicted to be related to suicidal behavior. Neurobiological and neuroendocrinological substrates such as serotonin, dopamine, cortisol (HPA axis), nitric oxide, serum cholesterol, epinephrine, norepinephrine, gonadal hormones (e.g., estradiol and progesterone), dehydroepiandrosterone (DHEA) in brain regiouns such as the orbitofrontal/dorsolateral prefrontal cortex and limbic regions (e.g., the amygdala) may supposedly be related to the neuroeconomic parameters modulating the risk of suicide. The present framework puts foundations for "molecular neuroeconomics" of decision-making processes underlying suicidal behavior. © 2011 Neuroendocrinology Letters.
Tamura M.,Kao Corporation |
Shimizu K.-I.,Hokkaido University |
Satsuma A.,Nagoya University
Applied Catalysis A: General | Year: 2012
Acid/base properties (type, strength, number) of a wide range of metal oxides were studied by IR (infra-red) spectroscopy. Ammonia, pyridine and CD 3CN were used as probe molecules for acidity measurement. CO 2, CHCl 3, benzaldehyde and nitrobenzene were used for basicity measurement. Pyridine for the nature and number of acid sites, CD 3CN for the strength of acid sites, CHCl 3 for the strength of basic sites and nitrobenzene for the number of basic sites were found to be suitable probes. The absorption coefficients of pyridine for acidic sites and nitrobenzene for basic sites, estimated for various metal oxides by IR coupled with mass spectrometry, were within ±10% of the average value, which indicates that the integrated molar extinction coefficients could be used for semi-quantification of acid/base sites of various oxides samples. The comprehensive IR results in this study will be available to characterize properties of Lewis and Bronsted acid sites and basic sites on metal oxides by a simple IR experiment. © 2012 Elsevier B.V.
Kuroda Y.,Meteorological Research Institute |
Yamazaki K.,Hokkaido University
Geophysical Research Letters | Year: 2010
Influence of the 11-year solar cycle and the stratospheric equatorial Quasi-Biennial Oscillation (QBO) on the Southern Annular Mode (SAM) in late winter/spring is examined through the analysis of combined reanalysis data of ECMWF. It is found that the signal is strongly affected by both the solar cycle and the QBO. Regarding the effect of the solar cycle, the signal extends to the upper stratosphere and persists into the following summer in years with high solar activity, but it is restricted to the troposphere and disappears very quickly in years with low solar activity. For the QBO, the signal extends to the upper stratosphere in late winter/spring but disappears in the following summer in QBO-west years. On the other hand, the signal extends vertically as the time evolution and tends to persist into the following summer in QBO-east years. When both the solar cycle and the QBO are considered, the effects from the solar cycle dominate and those from the QBO work as linearly superimposed factors. Role of ozone on the solar cycle and QBO modulation is also discussed. Copyright 2010 by the American Geophysical Union.
Kondo K.,Hokkaido University
New Journal of Physics | Year: 2016
Many researchers have reported on spin filters using linear Rashba spin-orbit interactions (SOI). However, spin filters using square and cubic Rashba SOIs have not yet been reported. We consider that this is because the Aharonov-Casher (AC) phases acquired under square and cubic Rashba SOIs are ambiguous. In this study, we try to derive the AC phases acquired under square and cubic Rashba SOIs from the viewpoint of non-Abelian SU(2) gauge theory. These AC phases can be derived successfully from the non-Abelian SU(2) gauge theory without the completing square methods. Using the results, we investigate the spin filtering in a double quantum dot (QD) Aharonov-Bohm (AB) ring under linear, square, and cubic Rashba SOIs. This AB ring consists of elongated QDs and quasi-one-dimensional quantum nanowires under an external magnetic field. The spin transport is investigated from the left nanowire to the right nanowire in the above structure within the tight-binding approximation. In particular, we focus on the difference of spin filtering among linear, square, and cubic Rashba SOIs. The calculation is performed for the spin polarization by changing the penetrating magnetic flux for the AB ring subject to linear, square, and cubic Rashba SOIs. It is found that perfect spin filtering is achieved for all of the Rashba SOIs. This result indicates that this AB ring under general Rashba SOIs can be a promising device for spin current generation. Moreover, the AB rings under general Rashba SOIs behave in totally different ways in response to penetrating magnetic flux, which is attributed to linear, square, and cubic behaviors in the in-plane momentum. This result enables us to make a clear distinction between linear, square, and cubic Rashba SOIs according to the peak position of the perfect spin filtering. © 2016 IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.
Kita T.,Hokkaido University
Progress of Theoretical Physics | Year: 2010
In this article, we present a concise and self-contained introduction to nonequilibrium statistical mechanics with quantum field theory by considering an ensemble of interacting identical bosons or fermions as an example. Readers are assumed to be familiar with the Matsubara formalism of equilibrium statistical mechanics such as Feynman diagrams, the proper self-energy, and Dyson's equation. The aims are threefold: (i) to explain the fundamentals of nonequilibrium quantum field theory as simple as possible on the basis of the knowledge of the equilibrium counterpart; (ii) to elucidate the hierarchy in describing nonequilibrium systems from Dyson's equation on the Keldysh contour to the Navier-Stokes equation in fluid mechanics via quantum transport equations and the Boltzmann equation; (iii) to derive an expression of nonequilibrium entropy that evolves with time. In stage (i), we introduce nonequilibrium Green's function and the self-energy uniquely on the roundtrip Keldysh contour, thereby avoiding possible confusions that may arise from defining multiple Green's functions at the very beginning. We try to present the Feynman rules for the perturbation expansion as simple as possible. In particular, we focus on the selfconsistent perturbation expansion with the Luttinger-Ward thermodynamic functional, i.e., Baym's Φ-derivable approximation, which has a crucial property for nonequilibrium systems of obeying various conservation laws automatically. We also show how the two-particle correlations can be calculated within the Φ-derivable approximation, i.e., an issue of how to handle the "Bogoliubov-Born-Green-Kirkwood-Yvons (BBGKY) hierarchy". Aim (ii) is performed through successive reductions of relevant variables with the Wigner transformation, the gradient expansion based on the Groenewold-Moyal product, and Enskog's expansion from local equilibrium. This part may be helpful for convincing readers that nonequilibrium systems can be handled microscopically with quantum field theory, including fluctuations. We also discuss a derivation of the quantum transport equations for electrons in electromagnetic fields based on the gauge-invariant Wigner transformation so that the Lorentz force is reproduced naturally. As for (iii), the Gibbs entropy of equilibrium statistical mechanics suffers from the flaw that it does not evolve in time. We show here that a microscopic expression of nonequilibrium dynamical entropy can be derived from the quantum transport equations so as to be compatible with the law of increase in entropy as well as equilibrium statistical mechanics.
Obara K.,Hokkaido University |
Ohsumi Y.,Tokyo Institute of Technology
International Journal of Cell Biology | Year: 2011
Phosphorylation of phosphatidylinositol (PtdIns) by a PtdIns 3-kinase is an essential process in autophagy. Atg14, a specific subunit of one of the PtdIns 3-kinase complexes, targets the complex to the probable site of autophagosome formation, thereby, sorting the complex to function specifically in autophagy. The N-terminal half of Atg14, containing coiled-coil domains, is required to form the PtdIns 3-kinase complex and target it to the proper site. The C-terminal half of yeast Atg14 is suggested to be involved in the formation of a normal-sized autophagosome. The C-terminal half of mammalian Atg14 contains the Barkor/Atg14(L) autophagosome-targeting sequence (BATS) domain that preferentially binds to the highly curved membranes containing PtdIns(3)P and is proposed to target the PtdIns 3-kinase complex efficiently to the isolation membrane. Thus, the N- and C-terminal halves of Atg14 are likely to have an essential core function and a regulatory role, respectively. Copyright © 2011 Keisuke Obara and Yoshinori Ohsumi.
Ohkubo S.,Kochi University |
Ohkubo S.,Osaka University |
Hirabayashi Y.,Hokkaido University
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2010
The existence of a rotational band with the α + 12C (02 +) cluster structure, in which three α particles in 12C(02 +) are locally condensed, is demonstrated near the four-α threshold of 16O in agreement with experiment. This is achieved by studying structure and scattering for the α + 12C (02 +) system in a unified way. A drastic reduction (quenching) of the moment of the inertia of the 0+ state at 15.1 MeV just above the four-α threshold in 16O suggests that it could be a candidate for the superfluid state in α-particle condensation. © 2010 Elsevier B.V. All rights reserved.
Masuda K.,Hokkaido University
Journal of Experimental Botany | Year: 2013
The nucleoskeleton of plants contains a peripheral lamina (also called plamina) and, even though lamins are absent in plants, their roles are still fulfilled in plant nuclei. One of the most intriguing topics in plant biology concerns the identity of lamin protein analogues in plants. Good candidates to play lamin functions in plants are the members of the NMCP (nuclear matrix constituent protein) family, which exhibit the typical tripartite structure of lamins. This paper describes a bioinformatics analysis and classification of the NMCP family based on phylogenetic relationships, sequence similarity and the distribution of conserved regions in 76 homologues. In addition, NMCP1 in the monocot Allium cepa characterized by its sequence and structure, biochemical properties, and subnuclear distribution and alterations in its expression throughout the root were identified. The results demonstrate that these proteins exhibit many similarities to lamins (structural organization, conserved regions, subnuclear distribution, and solubility) and that they may fulfil the functions of lamins in plants. These findings significantly advance understanding of the structural proteins of the plant lamina and nucleoskeleton and provide a basis for further investigation of the protein networks forming these structures. © 2013 The Authors.
Mitroy J.,Charles Darwin University |
Bubin S.,Vanderbilt University |
Horiuchi W.,Hokkaido University |
Suzuki Y.,Niigata University |
And 7 more authors.
Reviews of Modern Physics | Year: 2013
The variational method complemented with the use of explicitly correlated Gaussian basis functions is one of the most powerful approaches currently used for calculating the properties of few-body systems. Despite its conceptual simplicity, the method offers great flexibility, high accuracy, and can be used to study diverse quantum systems, ranging from small atoms and molecules to light nuclei, hadrons, quantum dots, and Efimov systems. The basic theoretical foundations are discussed, recent advances in the applications of explicitly correlated Gaussians in physics and chemistry are reviewed, and the strengths and weaknesses of the explicitly correlated Gaussians approach are compared with other few-body techniques. © 2013 American Physical Society.
Jinushi M.,Hokkaido University
International Journal of Cancer | Year: 2014
Pattern recognition-mediated sensing systems direct host immunity towards either antitumor immunosurveillance or protumorigenic inflammation. These activities imply dual and conflicting roles in the regulation of tumor-associated inflammation. On the one hand, recent evidence has revealed that several signaling components and cell-surface receptors suppress innate immune signals and constitute a negative feedback machinery preventing excess and continuous inflammation within tumor microenvironments. On the other hand, these same components also negatively regulate intrinsic tumorigenic activities by targeting nuclear factor-kappaB (NF-κB)-mediated antiapoptotic and inflammatory signals. Furthermore, the activation status of innate immune suppressors may reflect the functional plasticity of interactions between tumor cells and innate immune cells and determine whether tumor inflammation supports anti- or pro-tumorigenic responses. Thus, innate immune suppressors may provide valuable information about the immunogenic or tumorigenic status of tumor-associated inflammation thereby serving as potential biomarkers that predict tumor progression. Comprehensive analysis for identifying general and unique features of each innate immune suppressor in the regulation of tumor inflammation should explore the development of new biomarkers for improving future therapeutic strategies. © 2013 UICC.
Nishie W.,Hokkaido University
Journal of Dermatological Science | Year: 2014
Bullous pemphigoid (BP) is a common autoimmune blistering skin disorder that tends to affect the elderly. Autoantibodies (autoAbs) from BP patients react with two hemidesmosomal components: transmembrane collagen XVII (BP180 or BPAG2) and plakin family protein BP230 (BPAG1). Of these, collagen XVII (COL17) is thought to be a major autoantigen. The binding of autoAbs to COL17 following the activation of complements and inflammatory pathways eventually leads to the degradation of COL17, and this has been regarded as the main pathogenesis of BP. However, recent investigations have suggested other pathways, including a complement-independent pathway and a pathway involving IgE-autoAbs. BP-autoAbs can directly deplete COL17, leading to fragility of the dermal-epidermal junction. In addition, IgE-autoAbs to COL17 may be involved in the formation of itchy urticarial erythema associated with eosinophilic infiltration. This article summarizes the update on pathogenesis of BP, with a special focus on blister formation by autoAbs to COL17. © 2013 Japanese Society for Investigative Dermatology.
Ito H.,Hokkaido University |
Kakutani T.,National Institute of Genetics
Chromosome Research | Year: 2014
Arabidopsis thaliana serves as a very good model organism to investigate the control of transposable elements (TEs) by genetic and genomic approaches. As TE movements are potentially deleterious to the hosts, hosts silence TEs by epigenetic mechanisms, such as DNA methylation. DNA methylation is controlled by DNA methyltransferases and other regulators, including histone modifiers and chromatin remodelers. RNAi machinery directs DNA methylation to euchromatic TEs, which is under developmental control. In addition to the epigenetic controls, some TEs are controlled by environmental factors. TEs often affect expression of nearby genes, providing evolutionary sources for epigenetic, developmental, and environmental gene controls, which could even be beneficial for the host. © 2014 Springer Science+Business Media.
Iwakiri D.,Hokkaido University
Cancers | Year: 2014
The Epstein-Barr virus (EBV) is known as an oncogenic herpes virus that has been implicated in the pathogenesis of various malignancies. EBV-encoded RNAs (EBERs) are non-coding RNAs expressed abundantly in latently EBV-infected cells. Herein, I summarize the current understanding of the functions of EBERs, including the interactions with cellular factors through which EBERs contribute to EBV-mediated pathogenesis. Previous studies have demonstrated that EBERs are responsible for malignant phenotypes in lymphoid cells, and can induce several cytokines that can promote the growth of various EBV-infected cancer cells. EBERs were also found to bind retinoic acid-inducible gene I (RIG-I) and thus activate its downstream signaling. Furthermore, EBERs induce interleukin-10, an autocrine growth factor for Burkitt's lymphoma cells, by activating RIG-I/interferon regulatory factor 3 pathway, suggesting that EBER-mediated innate immune signaling modulation contributes to EBV-mediated oncogenesis. Recently, EBV-infected cells were reported to secret EBERs, which were then recognized by toll-like receptor 3 (TLR3), leading to the induction of type I interferon and inflammatory cytokines, and subsequent immune activation. Furthermore, EBER1 was detected in the sera of patients with active EBV-infectious diseases, suggesting that EBER1-meidated TLR3 signaling activation could account for the pathogenesis of active EBV-infectious diseases. © 2014 by the authors; licensee MDPI, Basel, Switzerland.
Komohara Y.,Kumamoto University |
Jinushi M.,Hokkaido University |
Takeya M.,Kumamoto University
Cancer Science | Year: 2014
The fact that various immune cells, including macrophages, can be found in tumor tissue has long been known. With the recent introduction of the novel concept of macrophage differentiation into a classically activated phenotype (M1) and an alternatively activated phenotype (M2), the role of tumor-associated macrophages (TAMs) is gradually beginning to be elucidated. Specifically, in human malignant tumors, TAMs that have differentiated into M2 macrophages act as "protumoral macrophages" and contribute to the progression of disease. Based on recent basic and preclinical research, TAMs that have differentiated into protumoral or M2 macrophages are believed to be intimately involved in the angiogenesis, immunosuppression, and activation of tumor cells. In this paper, we specifically discuss both the role of TAMs in human malignant tumors and the cell-cell interactions between TAMs and tumor cells. © 2013 The Authors.
Ishii T.,Hokkaido University
Reproductive BioMedicine Online | Year: 2014
Previous discussions regarding human germline gene modification led to a global consensus that no germline should undergo genetic modification. However, the UK Human Fertilisation and Embryology Authority, having conducted at the UK Government's request a scientific review and a wide public consultation, provided advice to the Government on the pros and cons of Parliament's lifting a ban on altering mitochondrial DNA content of human oocytes and embryos, so as to permit the prevention of maternal transmission of mitochondrial diseases. In this commentary, relevant ethical and biomedical issues are examined and requirements for proceeding with this novel procedure are suggested. Additionally, potentially significant impacts of the UK legalization on global policy concerning germline gene modification are discussed in the context of recent advances in genome-editing technology. It is concluded that international harmonization is needed, as well as further ethical and practical consideration, prior to the legalization of human mitochondrial replacement. © 2014 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.
Jinushi M.,Hokkaido University
Cancer and Metastasis Reviews | Year: 2014
Emerging evidence has unveiled a critical role for immunological parameters in predicting tumor prognosis and clinical responses to anticancer therapeutics. On the other hand, responsiveness to anticancer drugs greatly modifies the repertoires, phenotypes, and immunogenicity of tumor-infiltrating immune cells, serving as a critical factor to regulate tumorigenic activities and the emergence of therapy-resistant phenotypes. Tumor-associated immune functions are influenced by distinct or overlapping sets of therapeutic modalities, such as cytotoxic chemotherapy, radiotherapy, or molecular-targeted therapy, and various anticancer modalities have unique properties to influence the mode of cross-talk between tumor cells and immune cells in tumor microenvironments. Thus, it is critical to understand precise molecular machineries whereby each anticancer strategy has a distinct or overlapping role in regulating the dynamism of reciprocal communication between tumor and immune cells in tumor microenvironments. Such an understanding will open new therapeutic opportunities by harnessing the immune system to overcome resistance to conventional anticancer drugs. © 2014 Springer Science+Business Media.
Yamagishi M.,Hokkaido University
Molecular Breeding | Year: 2011
Anthocyanins are the predominant visible pigments in flowers of the Oriental hybrid lily (Lilium spp.). To understand the regulatory mechanisms of flower coloration in this hybrid lily, full-length cDNA of the R2R3-MYB gene, LhSorMYB12, was isolated from anthocyanin-accumulating tepals of the cultivar Sorbonne. The deduced amino acid sequence of LhSorMYB12 showed 85% (209/246) identity, including a gap of seven amino acids, with an amino acid sequence in LhMonMYB12 that regulates anthocyanin biosynthesis in the Asiatic hybrid lily. Transcripts of LhSorMYB12 accumulated in anthocyanin-accumulating tepals of three cultivars but not in white tepals of two other cultivars. The white-tepal cultivar Rialto showed LhMYB12 transcription in tepals, but the Rialto sequence contained amino acid replacements in the R2 repeat, resulting in reduced transcription of anthocyanin biosynthesis genes and in no pigmentation. Spatial and temporal transcription of LhSorMYB12 showed that transcription of LhMYB12 corresponded well with transcription of anthocyanin biosynthesis genes in tepal regions where anthocyanins accumulated and in anthocyanin spots on tepals. These results indicate that LhSorMYB12 definitely regulates anthocyanin biosynthesis and is responsible for the tepal color difference between Oriental hybrid lily cultivars. © 2010 Springer Science+Business Media B.V.
Akimoto S.-I.,Hokkaido University
Ecology and Evolution | Year: 2014
To evaluate the impact of fallout from the Fukushima Daiichi Nuclear Power Plant accident on organisms, this study compared the morphology and viability of gall-forming aphids between the Fukushima population and control populations from noncontaminated areas. This study, in particular, focused on the morphology of first-instar gall formers derived from the first sexual reproduction after the accident. Of 164 first instars from Tetraneura sorini galls collected 32 km from Fukushima Daiichi in spring 2012, 13.2% exhibited morphological abnormalities, including four conspicuously malformed individuals (2.4%). In contrast, in seven control areas, first instars with abnormal morphology accounted for 0.0-5.1% (on average, 3.8%). The proportions of abnormalities and mortality were significantly higher in Fukushima than in the control areas. Similarly, of 134 first instars from T. nigriabdominalis galls, 5.9% exhibited morphological abnormalities, with one highly malformed individual. However, of 543 second-generation larvae produced in T. sorini galls, only 0.37% had abnormalities, suggesting that abnormalities found in the first generation were not inherited by the next generation. Although investigation is limited to one study site, this result suggests that radioactive contamination had deleterious effects on embryogenesis in eggs deposited on the bark surface, but a negligible influence on the second generation produced in closed galls. Furthermore, analysis of both species samples collected in spring 2013 indicated that the viability and healthiness of the aphids were significantly improved compared to those in the 2012 samples. Thus, the results of this study suggest the possibility that a reduced level of radiation and/or selection for radiation tolerance may have led to the improved viability and healthiness of the Fukushima population. © 2014 The Author. Ecology and Evolution published by John Wiley & Sons Ltd.
Natsuga K.,Hokkaido University
Cold Spring Harbor Perspectives in Medicine | Year: 2014
The epidermis functions as a physical barrier to the external environment and works to prevent loss of water from the skin. Numerous factors have been implicated in the formation of epidermal barriers, such as cornified envelopes, corneocytes, lipids, junctional proteins, proteases, protease inhibitors, antimicrobial peptides, and transcription factors. This review illustrates human diseases (ichthyoses) and animal models in which the epidermal barrier is disrupted or dysfunctional at steady state owing to ablation of one or more of the above factors. These diseases and animal models help us to understand the complicated mechanisms of epidermal barrier formation and give further insights on epidermal development. © 2014 Cold Spring Harbor Laboratory Press; all rights reserved.
Kihara A.,Hokkaido University
Biochimica et Biophysica Acta - Molecular and Cell Biology of Lipids | Year: 2014
The sphingolipid metabolite sphingosine 1-phosphate (S1P) is a well-known lipid mediator. As a lipid mediator, S1P must be present in extracellular space and bind to its cell surface receptors (S1P1-5). However, most S1P, synthesized intracellularly, is metabolized without being released into extracellular space, in other words, without functioning as a lipid mediator in the vast majority of cells except those supplying plasma and lymph S1P such as blood cells and endothelial cells. Instead, intracellular S1P plays an important role as an intermediate of the sole sphingolipid-to-glycerophospholipid metabolic pathway. The degradation of S1P by S1P lyase is the first irreversible reaction (committed step) of this pathway. This metabolic pathway is conserved in eukaryotes from yeast to human, indicating its much older origin than the function of S1P as a lipid mediator, which is found to be present only in vertebrates and chordates. The sphingolipid-to-glycerophospholipid metabolism takes place ubiquitously in mammalian tissues, and its defect causes an aberration of several tissue functions as well as abnormal lipid metabolism. Although this metabolic pathway has been known for over four decades, only recently the precise reactions and enzymes involved in this pathway have been revealed. This review will focus on the recent advances in our understanding of the sphingolipid metabolic pathway via S1P and its physiological and pathological roles. This article is part of a Special Issue entitled New Frontiers in Sphingolipid Biology. © 2013 Elsevier B.V.
Hirose T.,Hokkaido University |
Mishima Y.,University of Tokyo |
Mishima Y.,Tokyo Medical University |
Tomari Y.,University of Tokyo |
Tomari Y.,Tokyo Medical University
EMBO Reports | Year: 2014
Although recent transcriptome analyses have uncovered numerous non-coding RNAs (ncRNAs), their functions remain largely unknown. ncRNAs assemble with proteins and operate as ribonucleoprotein (RNP) machineries, formation of which is thought to be determined by specific fundamental elements embedded in the primary RNA transcripts. Knowledge about the relationships between RNA elements, RNP machinery, and molecular and physiological functions is critical for understanding the diverse roles of ncRNAs and may eventually allow their systematic classification or "taxonomy." In this review, we catalog and discuss representative small and long non-coding RNA classes, focusing on their currently known (and unknown) RNA elements and RNP machineries. This review compares the RNA elements, processing proteins, RNP machineries, and ncRNA functions of siRNA, miRNA, piRNA, crRNA, and lncRNA classes and proposes that knowledge of the relationship between these elements might enable the systematic classification of ncRNAs. © 2014 The Authors.
Jinushi M.,Hokkaido University
OncoImmunology | Year: 2012
Innate immunity serves as a first line of defense against infectious agents, and germ-line-encoded pattern recognition receptors detect stressed and infected cells and elicit potent effector activities that accomplish efficient microbe containment. Recent evidence demonstrates that these patternsensing systems are also applicable to the recognition of tumor-derived stress-related factors. In particular, toll-like receptors and cytosolic sensors for DNA and RNA recognition utilize endogenous host elements containing microbial components, danger-associated molecules, and/or nucleic acids to stimulate innate signaling pathways and generate protective immune responses against nascent tumors in animal models and humans. In this review, we describe recent advances and perspectives about antitumor mechanisms and clinical application of innate immune signals and pathways. © 2012 Landes Bioscience.
Uno T.,Kobe University |
Ishizuka M.,Hokkaido University |
Itakura T.,Kagoshima University
Environmental Toxicology and Pharmacology | Year: 2012
Cytochrome P450 (CYP) enzymes are members of the hemoprotein superfamily, and are involved in the mono-oxygenation reactions of a wide range of endogenous and exogenous compounds in mammals and plants. Characterization of CYP genes in fish has been carried out intensively over the last 20 years. In Japanese pufferfish (Takifugu rubripes), 54 genes encoding P450s have been identified. Across all species of fish, 137 genes encoding P450s have been identified. These genes are classified into 18 CYP families: namely, CYP1, CYP2, CYP3, CYP4, CYP5, CYP7, CYP8, CYP11, CYP17, CYP19, CYP20, CYP21, CYP24, CYP26, CYP27, CYP39, CYP46 and CYP51.We pinpointed eight CYP families: namely, CYP1, CYP2, CYP3, CYP4, CYP11, CYP17, CYP19 and CYP26 in this review because these CYP families are studied in detail. Studies of fish P450s have provided insights into the regulation of P450 genes by environmental stresses including water pollution. In this review, we present an overview of the CYP families in fish. © 2012 Elsevier B.V.
Yoshizawa K.,Hokkaido University |
Ferreira R.L.,Federal University of Lavras |
Kamimura Y.,Keio University |
Lienhard C.,Natural History Museum of the City of Geneva
Current Biology | Year: 2014
Sex-specific elaborations are common in animals and have attracted the attention of many biologists, including Darwin . It is accepted that sexual selection promotes the evolution of sex-specific elaborations. Due to the faster replenishment rate of gametes, males generally have higher potential reproductive and optimal mating rates than females. Therefore, sexual selection acts strongly on males , leading to the rapid evolution and diversification of male genitalia . Male genitalia are sometimes used as devices for coercive holding of females as a result of sexual conflict over mating [4, 5]. In contrast, female genitalia are usually simple. Here we report the reversal of intromittent organs in the insect genus Neotrogla (Psocodea: Prionoglarididae) from Brazilian caves. Females have a highly elaborate, penis-like structure, the gynosome, while males lack an intromittent organ. The gynosome has species-specific elaborations, such as numerous spines that fit species-specific pouches in the simple male genital chamber. During prolonged copulation (∼40-70 hr), a large and potentially nutritious ejaculate is transferred from the male via the gynosome. The correlated genital evolution in Neotrogla is probably driven by reversed sexual selection with females competing for seminal gifts. Nothing similar is known among sex-role reversed animals. © 2014 Elsevier Ltd.
Asano T.,Hokkaido University
Rheumatology (Oxford, England) | Year: 2014
The role of the joint tissue microenvironment in the pathogenesis of human RA has recently attracted much attention. The present study investigated the roles of α9β1 integrin and its ligands in synovial specimens of human RA patients in generating the unique human arthritic tissue microenvironment. Synovial fibroblasts and macrophages were isolated from the synovial tissue of patients with RA or OA. The expression of α9β1 integrin was analysed using FACS with multicolour staining. The production of MMPs and proinflammatory cytokines was analysed in cultures of synovial fibroblasts and macrophages with α9β1 integrin ligands. Synovial fibroblasts and macrophages derived from arthritic joints spontaneously secreted tenascin-C and osteopontin. Synovial fibroblasts and macrophages obtained from patients with RA expressed α9β1 integrins, a common receptor for osteopontin and tenascin-C. In the synovial fibroblasts of RA, the amount of tenascin-C protein produced was much greater than that of osteopontin in synovial fibroblasts of RA. Importantly, autocrine and paracrine interactions of α9β1 integrin and tenascin-C induced the expression of MMPs and IL-6 in synovial fibroblasts, as well as TNF-α and IL-1β in synovial macrophages. These findings indicate that autocrine and paracrine interaction of α9β1 integrin and tenascin-C in the joint tissue microenvironment contributes to the pathogenesis of RA. Therefore α9β1 integrin may become a potential therapeutic target for RA.
Takahashi R.,Hokkaido University
Progress of Theoretical and Experimental Physics | Year: 2013
We propose a new seesaw model in an extra-dimensional setup where only right-handed neutrinos are bulk fields. In the model, the localizations of an extra-dimensional wave function and brane Majorana mass of the right-handed neutrinos can be different among each generation of the right-handed neutrinos. The setup can lead to different suppression factor dependences of the effective right-handed neutrino masses and neutrino Yukawa couplings for each generation. It is shown that the resultant mass spectra of the right-handed neutrinos and neutrino Yukawa couplings are favored in models of neutrino dark matter with baryogenesis. © 2013 The Author(s).
Chiba S.,Hokkaido University
Bioscience, Biotechnology and Biochemistry | Year: 2012
Various catalytic reaction models have been proposed as the reaction mechanisms of glycosidases, but a reasonable and unitary model capable of interpreting both "inverting" and "retaining" glycosidase reactions remains to be established. As for the models proposed to date, the nucleophilic displacement mechanism and the oxocarbenium ion intermediate mechanism are widely known, but recently the former is widely accepted, and so the general tendency of world opinion appears to favor it. This reaction model, however, is considered to comprise some inconsistencies that cannot be neglected from the viewpoint of reactivity in organic chemistry. While the nucleophilic displacement mechanism is often applied to reactions of glycosidases, it appears unlikely that such reactions actually occur. This review argues that the oxocarbenium ion intermediate reaction mechanism is more rational than the nucleophilic displacement reaction mechanism, as the action mode of glycosidases and related enzymes. © 2012 W. S. Maney & Son Ltd.
Tamura T.,University of Tasmania |
Tamura T.,Japan National Institute of Polar Research |
Ohshima K.I.,Hokkaido University
Journal of Geophysical Research: Oceans | Year: 2011
High ice production in coastal polynyas over the continental shelves in the Arctic Ocean is responsible for the formation of cold saline water, which contributes to the maintenance of the Arctic Ocean halocline. The accurate detection of coastal polynyas, including an estimate of thin ice thickness, is essential for the estimation of sea ice production. This paper presents an algorithm that estimates thin ice thickness using Special Sensor Microwave/Imager (SSM/I) data in the Arctic Ocean. Detection and estimation of sea ice thicknesses of <0.15 m are based on the SSM/I 85 and 37 GHz polarization ratios (PR85 and PR37) through a comparison with sea ice thicknesses estimated from the advanced very high resolution radiometer (AVHRR) data in the three different Arctic coastal polynyas. Thus, for the entire Arctic Ocean, the algorithm can be used for the detection of coastal polynyas and for the estimation of sea ice production through combination with heat-flux calculation. This study provides the first circumpolar mapping of sea ice production in coastal polynyas over the entire Arctic Ocean. High ice production is confined to the major Arctic coastal polynyas, with the highest ice production rate being in the North Water Polynya. This study also presents the interannual variability of sea ice production in the 10 major coastal polynyas from 1992 to 2007. In general, interannual variability in sea ice production has good correlation with polynya extent rather than surface air temperature. The mapping also provides surface heat- and salt- flux conditions in the ice-covered region, which have not been well understood to date. Copyright 2011 by the American Geophysical Union.
Toyoda K.,Chiba University |
Miyamoto K.,Chiba University |
Aoki N.,Chiba University |
Morita R.,Hokkaido University |
And 2 more authors.
Nano Letters | Year: 2012
We discovered for the first time that light can twist metal to control the chirality of metal nanostructures (hereafter, chiral metal nanoneedles). The helicity of optical vortices is transferred to the constituent elements of the irradiated material (mostly melted material), resulting in the formation of chiral metal nanoneedles. The chirality of these nanoneedles could be controlled by just changing the sign of the helicity of the optical vortex. The tip curvature of these chiral nanoneedles was measured to be <40 nm, which is less than 1/25th of the laser wavelength (1064 nm). Such chiral metal nanoneedles will enable us to selectively distinguish the chirality and optical activity of molecules and chemical composites on a nanoscale and they will provide chiral selectivity for nanoscale imaging systems (e.g., atomic force microscopes), chemical reactions on plasmonic nanostructures, and planar metamaterials. © 2012 American Chemical Society.
Yamagishi M.,Hokkaido University
Molecular Breeding | Year: 2016
Color patterns in angiosperm flowers are produced by spatially and temporally restricted deposition of pigments. Many Lilium species show anthocyanin pigmentation of the whole tepal, which is regulated by the MYB12/basic helix-loop-helix 2 (bHLH2) transcription factor complex. However, in Lilium regale pigment deposition is restricted to light-exposed surfaces of the flower buds, leaves, and bracts. Investigation of how the unique color patterns of L. regale are regulated led to the identification and isolation of a novel R2R3-MYB gene, LrMYB15. In stable and transient transformation assays in tobacco, LrMYB15 stimulated transcription of anthocyanin biosynthesis genes, indicating that it is involved in the positive regulation of anthocyanins. In L. regale, anthocyanin biosynthesis genes and LrMYB15 were expressed in the outer tepals, leaves, and bracts that accumulated anthocyanin pigments. In contrast, LrbHLH2, another regulatory gene for anthocyanin biosynthesis, was transcribed in all organs irrespective of anthocyanin accumulation. These results indicate that LrMYB15 principally determines the unique anthocyanin color patterns of L. regale. In addition, LrMYB15 transcription ceased completely when plants were kept in shaded conditions and the colors of the flower buds faded, indicating that transcription of this gene is under the control of light. R2R3-MYB genes that regulate light-induced anthocyanin accumulation on exposed petal surfaces have been isolated in eudicots. The results here indicate that R2R3-MYB genes exhibiting similar (but not identical) functions are conserved between monocots and eudicots and that transcriptional regulation is a major mechanism for generating restricted pigment deposition in the flowers of a wide range of angiosperm species. © 2015, Springer Science+Business Media Dordrecht.
Tsubakihara K.,Hokkaido University |
Ohnishi A.,Kyoto University
Nuclear Physics A | Year: 2013
We develop a relativistic mean field (RMF) model with explicit three-body couplings and apply it to hyperonic systems and neutron star matter. Three-baryon repulsion is a promising ingredient to answer the massive neutron star puzzle; when strange hadrons such as hyperons are taken into account, the equation of state (EOS) becomes too soft to support the observed two-solar-mass neutron star. We demonstrate that it is possible to consistently explain the massive neutron star and hypernuclear data when we include three-body couplings and modify the hyperon-vector meson couplings from the flavor SU(3) value. © 2013 Elsevier B.V.
Crow K.D.,San Francisco State University |
Munehara H.,Hokkaido University |
Bernardi G.,University of California at Santa Cruz
Molecular Ecology | Year: 2010
Sympatric speciation has been contentious since its inception, yet is increasingly recognized as important based on accumulating theoretical and empirical support. Here, we present a compelling case of sympatric speciation in a taxon of marine reef fishes using a comparative and mechanistic approach. Hexagrammos otakii and H. agrammus occur in sympatry throughout their ranges. Molecular sequence data from six loci, with complete sampling of the genus, support monophyly of these sister species. Although hybridization occurrs frequently with an allopatric congener in an area of slight distributional overlap, we found no F 1 hybrids between the focal sympatric taxa throughout their coextensive ranges. We present genetic evidence for complete reproductive isolation based on SNP analysis of 382 individuals indicating fixed polymorphisms, with no shared haplotypes or genotypes, between sympatric species. To address questions of speciation, we take a mechanistic approach and directly compare aspects of reproductive isolation between allopatric and sympatric taxa both in nature and in the laboratory. We conclude that the buildup of reproductive isolation is strikingly different in sympatric vs. allopatric taxa, consistent with theoretical predictions. Lab reared hybrids from allopatric species crosses exhibit severe fitness effects in the F 1 or backcross generation. No intrinsic fitness effects are observed in F 1 hybrids from sympatric species pairs, however these treatments exhibited reduced fertilization success and complete pre-mating isolation is implied in nature because F 1 hybrid adults do not occur. Our study addresses limitations of previous studies and supports new criteria for inferring sympatric speciation. © 2010 Blackwell Publishing Ltd.
Takahashi T.,Hokkaido University
Topics in Cognitive Science | Year: 2014
Recently, mathematical models based on quantum formalism have been developed in cognitive science. The target articles in this special issue of Topics in Cognitive Science clearly illustrate how quantum theoretical formalism can account for various aspects of human judgment and decision making in a quantitatively and mathematically rigorous manner. In this commentary, we show how future studies in quantum cognition and decision making should be developed to establish theoretical foundations based on physical theory, by introducing Taketani's three-stage theory of the development of science. Also, implications for neuroeconomics (another rapidly evolving approach to human judgment and decision making) are discussed. © 2013 Cognitive Science Society, Inc.
Takada A.,Hokkaido University
Frontiers in Microbiology | Year: 2012
In human and non-human primates, filoviruses (Ebola and Marburg viruses) cause severe hemorrhagic fever. Recently, other animals such as pigs and some species of fruit bats have also been shown to be susceptible to these viruses. While having a preference for some cell types such as hepatocytes, endothelial cells, dendritic cells, monocytes, and macrophages, filoviruses are known to be pantropic in infection of primates. The envelope glycoprotein (GP) is responsible for both receptor binding and fusion of the virus envelope with the host cell membrane. It has been demonstrated that filovirus GP interacts with multiple molecules for entry into host cells, whereas none of the cellular molecules so far identified as a receptor/co-receptor fully explains filovirus tissue tropism and host range. Available data suggest that the mucin-like region (MLR) on GP plays an important role in attachment to the preferred target cells, whose infection is likely involved in filovirus pathogenesis, whereas the MLR is not essential for the fundamental function of the GP in viral entry into cells in vitro. Further studies elucidating the mechanisms of cellular entry of filoviruses may shed light on the development of strategies for prophylaxis and treatment of Ebola and Marburg hemorrhagic fevers. © 2012 Takada.
Shida H.,Hokkaido University
Frontiers in Microbiology | Year: 2012
Retroviruses have evolved mechanisms for transporting their intron-containing RNAs (including genomic and messenger RNAs, which encode virion components) from the nucleus to the cytoplasm of the infected cell. Human retroviruses, such as human immunodeficiency virus (HIV) and human T cell leukemia virus type 1 (HTLV-1), encode the regulatory proteins Rev and Rex, which form a bridge between the viral RNA and the export receptor CRM1. Recent studies show that these transport systems are not only involved in RNA export, but also in the encapsidation of genomic RNA; furthermore, they influence subsequent events in the cytoplasm, including the translation of the cognate mRNA, transport of Gag proteins to the plasma membrane, and the formation of virus particles. Moreover, the mode of interaction between the viral and cellular RNA transport machinery underlies the species-specific propagation of HIV-1 and HTLV-1, forming the basis for constructing animal models of infection. This review article discusses recent progress regarding these issues. © 2012 Shida.
Fujita O.,Hokkaido University
Proceedings of the Combustion Institute | Year: 2015
This paper introduces fire safety standards for flammability evaluation of solid material intended for use in a spacecraft habitat. Two types of existing standards include material evaluation by pass/fail criteria corresponding to Test 1 of NASA STD 6001B and evaluation by a flammability index such as maximum oxygen concentration (MOC) corresponding to the improved Test 1. The advantage of the latter is the wide applicability of the MOC index to different atmospheres in spacecraft. Additionally, the limiting oxygen index (LOI) method is introduced as a potential alternative index for the evaluation using the improved Test 1 method. When criteria based on an index such as MOC or LOI are applied for material screening, the discrepancy of the index to the actual flammability limit in microgravity such as minimum limiting oxygen concentration (MLOC) is essential information for guaranteeing fire safety in space because material flammability can be higher in microgravity. In this paper, the existing research on the effects of significant parameters on material flammability in microgravity are introduced, and the difference between the limiting value in microgravity and the indices given by the standard test methods on the ground is discussed. Finally, on-going efforts to develop estimation methods of material flammability in microgravity according to normal gravity tests are summarized. © 2014 The Combustion Institute. Published by Elsevier Inc. All rights reserved.
Suemune I.,Hokkaido University
Optics Express | Year: 2013
Enhancement of optical absorption in thin-film solar cells (TF-SCs) has been the long-lasting issue to achieve high efficiencies. Grating couplers have been studied for the conversion of incident light into guided modes propagating along TF-SCs to extend optical path for higher optical absorption. However the wavelength band for the efficient conversion remained relatively narrow and the overall improvement of TF-SC efficiencies has been limited. This paper demonstrates that the grating height design as well as the phase matching condition is important for the enhancement of optical absorption in TF-SCs with the calculation of short-circuit currents as a figure of merit for optimization. The influence of the light absorption coefficients and grating coupling strengths on the light absorption bandwidth is also discussed. © 2013 Optical Society of America.
Morikawa M.,Hokkaido University
[Hokkaido igaku zasshi] The Hokkaido journal of medical science | Year: 2012
To determine the normal reference values for antithrombin (AT) activity, platelet count (Plt), hemoglobin concentration (Hb), and hematocrit value (Ht) immediately before vaginal delivery among healthy pregnant women with singleton pregnancies and to determine association of these blood parameters with fetal growth. A complete blood count was performed and the AT activity was examined in 300 consecutive women admitted to hospital at > or = gestational week 36 for labor pains and/or the rupture of fetal membranes. All the women were normotensive and had singleton pregnancies, and none of the women had proteinuria, a weekly weight gain > or = 0.5 kg, or other specific complications upon admission. All the women attempted a vaginal delivery. The medians (5th-95th percentile) were 90% (71-110%) for AT activity, 234x10(9)/L (150-337x10(9)/L) for Plt, 11.0 g/dL (9.5-12.8 g/dL) for Hb, and 34.0% (30.4-38.6%) for Ht. Women with an Hb value of > or = the median (11.0 g/dL) gave birth to significantly smaller infants than their counterparts. A considerable number of healthy women exhibit a reduced AT activity and/or platelet count immediately before delivery. Hemoconcentration evidenced by a raised Hb value adversely effects on infant growth. Our data may be helpful when considering the normal ranges of these blood parameters for healthy parturient women.
Kotani T.,Hokkaido University
Vitamins and Hormones | Year: 2012
Protein kinase A (PKA) is a well-known kinase that plays fundamental roles in a variety of biological processes. In Hedgehog-responsive cells, PKA plays key roles in proliferation and fate specification by modulating the transduction of Hedgehog signaling. In the absence of Hedgehog, a basal level of PKA activity represses the transcription of Hedgehog target genes. The main substrates of PKA in this process are the Ci/Gli family of bipotential transcription factors, which activate and repress Hedgehog target gene expression. PKA phosphorylates Ci/Gli, promoting the production of the repressor forms of Ci/Gli and thus repressing Hedgehog target gene expression. In contrast, the activation of Hedgehog signaling in response to Hedgehog increases the active forms of Ci/Gli, resulting in Hedgehog target gene expression. Because both decreased and increased levels of PKA activity cause abnormal cell proliferation and alter cell fate specification, the basal level of PKA activity in Hedgehog-responsive cells should be precisely regulated. However, the mechanism by which PKA activity is regulated remains obscure and appears to vary between cell types, tissues, and organisms. To date, two mechanisms have been proposed. One is a classical mechanism in which PKA activity is regulated by a small second messenger, cAMP; the other is a novel mechanism in which PKA activity is regulated by a protein, Misty somites. © 2012 Elsevier Inc.
Yamada Y.,Hokkaido University
Yakugaku zasshi : Journal of the Pharmaceutical Society of Japan | Year: 2012
Mitochondrial dysfunction has been implicated in a variety of human diseases, including cancer and neurodegenerative disorders. Effective medical therapies for such diseases will ultimately require the targeted delivery of therapeutic agents to mitochondria. This will likely be achieved through innovations in the areas of the nanotechnology of intracellular trafficking. Mitochondrial delivery systems for a variety of cargoes have been repored to date. However, only a limited number of approaches are available for delivering macromolecules directly to mitochondria. We previously reported on the construction of a MITO-Porter, a liposome-based carrier that introduces macromolecular cargos into mitochondria via membrane fusion. Using the green fluorescence protein as a model macromolecule in conjunction with analysis by confocal laser scanning microscopy, we were able to confirm the mitochondrial delivery of a macromolecule by the MITO-Porter. Moreover, we reported that the Dual Function MITO-Porter (DF-MITO-Porter) could efficiently deliver cargo to mitochondria, through endosomal and mitochondrial membranes via step-wise membrane fusion. Here, We will present our findings on the development of our mitochondrial drug delivery system, and discuss our attempts regarding mitochondrial gene delivery and therapy. Finally, We will discuss the potential use of mitochondrial drug delivery systems in mitochondrial medicine.
Egawa K.,Massachusetts General Hospital |
Egawa K.,Hokkaido University |
Fukuda A.,Hamamatsu University School of Medicine
Frontiers in Neural Circuits | Year: 2013
High-affinity extrasynaptic gamma-aminobutyric acid A (GABAA)receptors are tonically activated by low and consistent levels of ambient GABA, mediating chronic inhibition against neuronal excitability (tonic inhibition) and the modulation of neural development. Synaptic (phasic) inhibition is spatially and temporally precise compared with tonic inhibition, which provides blunt yet strong integral inhibitory force by shunting electrical signaling. Although effects of acute modification of tonic inhibition are known, its pathophysiological significance remains unclear because homeostatic regulation of neuronal excitability can compensate for long-term deficit of extrasynaptic GABAAreceptor activation. Nevertheless, tonic inhibition is of great interest for its pathophysiological involvement in central nervous system (CNS) diseases and thus as a therapeutic target. Together with the development of experimental models for various pathological states, recent evidence demonstrates such pathological involvements of tonic inhibition in neuronal dysfunction. This review focuses on the recent progress of tonic activation of GABAA conductance on the development and pathology of the CNS. Findings indicate that neuronal function in various brain regions are exacerbated with a gain or loss of function of tonic inhibition by GABA spillover. Disturbance of tonic GABAAconductance mediated by non-synaptic ambient GABA may result in brain mal-development.Therefore, various pathological states (epilepsy, motor dysfunctions, psychiatric disorders, and neurodevelopmental disorders) may be partly attributable to abnormal tonic GABAAconductances. Thus, the tone of tonic conductance and level of ambient GABA may be precisely tuned to maintain the regular function and development of the CNS. Therefore, receptor expression and factors for regulating the ambient GABA concentration are highlighted to gain a deeper understanding of pathology and therapeutic strategy for CNS diseases. © 2013 Egawa and Fukuda.
Jinzenji M.,Hokkaido University
Communications in Mathematical Physics | Year: 2013
In this paper, we extend our geometrical derivation of the expansion coefficients of mirror maps by localization computation to the case of toric manifolds with two Kähler forms. In particular, we consider Hirzebruch surfaces F 0, F 3 and Calabi-Yau hypersurface in weighted projective space P(1, 1, 2, 2, 2) as examples. We expect that our results can be easily generalized to arbitrary toric manifolds. © 2013 Springer-Verlag Berlin Heidelberg.
Saito H.,Hokkaido University
Journal of Regional Science | Year: 2015
We examine the organization and location choice of heterogeneous firms in a two-region economy. When some high-productivity firms engage in multiplant production, a reduction in transport costs causes two changes in a small region: the closure of plants by high-productivity multiplant firms and the relocation of low-productivity single-plant firms to the region. In the presence of high-productivity multiplant firms, therefore, a decline in transport costs reinforces the spatial sorting of firms by productivity, enlarging the productivity gap between large and small regions. Conversely, reducing investment costs weakens the spatial sorting effects on regional productivity disparities. © 2015 Wiley Periodicals, Inc.
Goto-Kazeto R.,Hokkaido University
The International journal of developmental biology | Year: 2010
Primordial germ cells (PGCs) generate gametes, the only cells that can transmit genetic information to the next generation. A previous report demonstrated that a fusion construct of green fluorescent protein (gfp) and zebrafish nos 1 3UTR mRNA could be used to label PGCs in a number of fish species. Here, we sought to exploit this labeling strategy to isolate teleost PGCs by flow cytometry (FCM), and to use these isolated PGCs to examine germ cell migration to the gonadal region. In zebrafish, medaka and goldfish, the PGCs were labeled by injecting the gfp-nos1 3UTR mRNA into 1- 4 cell embryos. When the embryos had developed to the somitogenesis or later stages, they were enzymatically disaggregated and GFP positive cells isolated using FCM. PGCs in the different species clustered in the same segments of the FCM scatter diagrams for total embryonic cells produced by plotting the forward scatter intensity against GFP intensity. In situ hybridization showed that the sorted zebrafish cells expressed vasa RNA in their cytoplasm, suggesting that they were PGCs. When the migration ability of the sorted cells from zebrafish was examined in an in vivo transplantation experiment, approximately 30% moved to the gonadal region of host embryos. These observations demonstrate that PGCs can be isolated without use of transgenic fishes and that the isolated PGCs retain the ability to migrate. Our data indicate that this technique will be of value for isolating PGCs from a range of fish species.
Tachikawa H.,Hokkaido University
Physical Chemistry Chemical Physics | Year: 2011
Ionization dynamics of a water dimer have been investigated by means of a direct ab initio molecular dynamics (MD) method. Two electronic state potential energy surfaces of (H 2O) 2 + (ground and first excited states, 2A′′ and 2A′) were examined as cationic states of (H 2O) 2 +. Three intermediate complexes were found as product channels. One is a proton transfer channel where a proton of H 2O + is transferred into the H 2O and then a complex composed of H 3O +(OH) was formed. The second is a face-to-face complex channel denoted by (H 2O-OH 2) + where the oxygen-oxygen atoms directly bind each other. Both water molecules are equivalent to each other. The third one is a dynamical complex where H 2O + and H 2O interact weakly and vibrate largely with a large intermolecular amplitude motion. The dynamics calculations showed that in the ionization to the 2A′′ state, a proton transfer complex H 3O +(OH) is only formed as a long-lived complex. On the other hand, in the ionization to the 2A′ state, two complexes, the face-to-face and dynamical complexes, were found as product channels. The proton of H 2O + was transferred to H 2O within 25-50 fs at the 2A′′ state, meaning that the proton transfer on the ground state is a very fast process. On the other hand, the decay process on the first excited state is a slow process due to the molecular rotation. The mechanism of the ionization dynamics of (H 2O) 2 was discussed on the basis of theoretical results. © the Owner Societies.
Zhao Y.,Hokkaido University
Molecular imaging | Year: 2013
Technetium 99m (99mTc)-annexin A5, a marker of ongoing apoptosis, is supposed to be useful in the detection of metabolically active atheroma. The aim of this study was to determine the potential of 99mTc-annexin A5 for evaluating the therapeutic effects of an angiotensin II receptor type 1 blocker (ARB) (telmisartan) on atherosclerosis. Male apolipoprotein E-/- mice were divided into telmisartan-treated (3 mg/kg/d, n = 10) and control (n = 10) groups. After 16 to 21 weeks of treatment, 99mTc-annexin A5 was injected and cryostat sections of aortic tissues (n = 10-12/aorta) were prepared. The 99mTc-annexin A5 accumulation level in the plaques was evaluated by autoradiography. Serial sections of the plaques were histologically examined to identify the lesion phenotypes (normal vessels, early lesions, atheromatous lesions, and fibrotic lesions), plaque size, macrophage infiltration levels, and lipid deposition levels. Telmisartan treatment significantly decreased the plaque size (0.05 ± 0.05 vs 0.11 ± 0.08, mm2), macrophage infiltration level (0.02 ± 0.02 vs 0.03 ± 0.02, mm2), lipid deposition level (0.01 ± 0.01 vs 0.02 ± 0.02, mm2), and 99mTc-annexin A5 accumulation level (1.30 ± 1.09 vs 2.15 ± 1.91, × 10-6/g). 99mTc-annexin A5 accumulation levels in the plaques positively correlated with macrophage infiltration (r = .69, p < .05) and lipid deposition (r = .66, p < .05) levels. Apoptosis imaging with 99mTc-annexin A5 may be useful for evaluating the therapeutic effects of ARBs on atherosclerosis.
Yuzawa S.,Hokkaido University
American Journal of Surgical Pathology | Year: 2016
Solitary fibrous tumor/hemangiopericytoma (SFT/HPC) is a mesenchymal tumor that can affect virtually any region of the body. SFT/HPC of the thoracic cavity and soft tissue has been histologically considered a single biological entity termed SFT; in fact, NAB2-STAT6 gene fusion was recently identified in both diseases. In contrast, meningeal SFT and HPC still need to be investigated in detail with regard to gene fusion variants. The aim of this study was to verify the frequency of NAB2-STAT6 fusion and the relationship between fusion variants and clinicopathologic findings of SFT/HPC, especially meningeal SFT/HPC. We examined the NAB2-STAT6 fusion by reverse transcription polymerase chain reaction with 4 cases of meningeal SFT and 13 cases of meningeal HPC. NAB2-STAT6 fusion transcripts were identified in 12 of 17 cases, including NAB2ex6-STAT6ex17 (4/17, 24%), NAB2ex6-STAT6ex16 and NAB2ex4-STAT6ex2 (3/17, 18%, respectively), and NAB2ex5-STAT6ex16 (2/17, 12%). Three cases showed a pseudopapillary pattern, and 2 of them carried NAB2ex6-STAT6ex17. In addition, our meta-analysis revealed that the major fusion variant in meningeal SFT/HPC was NAB2ex6-STAT6ex16/17 (29/54, 54%), which was also common in soft tissue and intraperitoneum/retroperitoneum but rare in thoracic SFT. Fusion variant significantly correlated with age and histologic diagnosis in meningeal SFT/HPC but not with prognosis. Our results represented that meningeal SFT and HPC were in a single biological spectrum with NAB2-STAT6 gene fusion as was nonmeningeal SFT and further confirmed the organ-specific tumorigenic process and morphologic differences on the basis of fusion variants in meningeal SFT/HPC. Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved.
Ziemnicka-Sylwester M.,Hokkaido University
Materials | Year: 2013
TiB2-based ceramic matrix composites (CMCs) were fabricated using elemental powders of Ti,B and C. The self-propagating high temperature synthesis (SHS) was carried out for the highly exothermic "in situ" reaction of TiB2 formation and the "tailing" synthesis of boron carbide characterized by weak exothermicity. Two series of samples were fabricated, one of them being prepared with additional milling of raw materials. The effects of TiB2 vol fraction as well as grain size of reactant were investigated. The results revealed that combustion was not successful for a TiB2:B4C molar ratio of 0.96, which corresponds to 40 vol% of TiB2 in the composite, however the SHS reaction was initiated and self-propagated for the intended TiB2:B4C molar ratio of 2.16 or above. Finally B13C2 was formed as the matrix phase in each composite. Significant importance of the grain size of the C precursor with regard to the reaction completeness, which affected the microstructure homogeneity and hardness of investigated composites, was proved in this study. The grain size of Ti powder did not influence the microstructure of TiB2 grains. The best properties (HV = 25.5 GPa, average grain size of 9 μm and homogenous microstructure),were obtained for material containing 80 vol% of TiB2, fabricated using a graphiteprecursor of 2 μm. © 2013 by the authors; licensee MDPI, Basel, Switzerland.
Sato T.,Hokkaido University |
Xue Y.,University of California at Los Angeles
Climate Dynamics | Year: 2013
Performance of a regional climate model (RCM), WRF, for downscaling East Asian summer season climate is investigated based on 11-summer integrations associated with different climate conditions with reanalysis data as the lateral boundary conditions. It is found that while the RCM is essentially unable to improve large-scale circulation patterns in the upper troposphere for most years, it is able to simulate better lower-level meridional moisture transport in the East Asian summer monsoon. For precipitation downscaling, the RCM produces more realistic magnitude of the interannual variation in most areas of East Asia than that in the reanalysis. Furthermore, the RCM significantly improves the spatial pattern of summer rainfall over dry inland areas and mountainous areas, such as Mongolia and the Tibetan Plateau. Meanwhile, it reduces the wet bias over southeast China. Over Mongolia, however, the performance of precipitation downscaling strongly depends on the year: the WRF is skillful for normal and wet years, but not for dry years, which suggests that land surface processes play an important role in downscaling ability. Over the dry area of North China, the WRF shows the worst performance. Additional sensitivity experiments testing land effects in downscaling suggest the initial soil moisture condition and representation of land surface processes with different schemes are sources of uncertainty for precipitation downscaling. Correction of initial soil moisture using the climatology dataset from GSWP-2 is a useful approach to robustly reducing wet bias in inland areas as well as to improve spatial distribution of precipitation. Despite the improvement on RCM downscaling, regional analyses reveal that accurate simulation of precipitation over East China, where the precipitation pattern is strongly influenced by the activity of the Meiyu/Baiu rainfall band, is difficult. Since the location of the rainfall band is closely associated with both lower-level meridional moisture transport and upper-level circulation structures, it is necessary to have realistic upper-air circulation patterns in the RCM as well as lower-level moisture transport in order to improve the circulation-associated convective rainfall band in East Asia. © 2012 Springer-Verlag Berlin Heidelberg.
Habe T.,Hokkaido University
Physical Review B - Condensed Matter and Materials Physics | Year: 2014
We theoretically study the phonon-mediated intersurface electron-electron interactions on the pseudo-two-dimensional metallic states at the two surfaces of a three-dimensional topological insulator. From a model of a three-dimensional topological insulator including the phonon excitation in it, we derive the effective Lagrangian which describes the two surface metallic states and the interaction between them. The intersurface electron-electron interactions can be either repulsive or attractive depending on parameters such as temperature, the speed of the phonon, and the Fermi velocity of the surface states. The attractive interaction removes the Dirac nodes from the two surface states as a result of the spontaneous symmetry breaking. On the basis of the calculated results, we also discuss how to tune the intersurface interaction. © 2014 American Physical Society.
Yoshinaka R.,Hokkaido University
Theoretical Computer Science | Year: 2011
Recently Clark and Eyraud (2007)  have shown that substitutable context-free languages, which capture an aspect of natural language phenomena, are efficiently identifiable in the limit from positive data. Generalizing their work, this paper presents a polynomial-time learning algorithm for new subclasses of multiple context-free languages with variants of substitutability. © 2010 Elsevier B.V. All rights reserved.
Takeuchi H.,Hokkaido University
Computational and Theoretical Chemistry | Year: 2013
Growth sequence patterns of molecular clusters have not been well elucidated. To examine structures of planar-molecule clusters, naphthalene, anthracene, phenanthrene, phenalene, naphthacene, and pyrene clusters with up to 10 molecules were theoretically investigated with the all-atom OPLS potential. The global-minimum geometries of the naphthalene dimer, trimer, and tetramer are consistent with the experimental data, suggesting that the model potential is useful for predicting the cluster geometries. The growth sequence patterns of the naphthalene, anthracene, phenanthrene, and naphthacene clusters are based on herringbone structures whereas the structures of the phenalene and pyrene clusters are amorphous. The magic numbers of the clusters are 7 or 8 except for the phenalene clusters. These numbers are used to discuss structural motifs of the clusters. © 2013 Elsevier B.V.
Toyota T.,Hokkaido University |
Haas C.,University of Alberta |
Tamura T.,University of Tasmania
Deep-Sea Research Part II: Topical Studies in Oceanography | Year: 2011
In the marginal sea ice zone (MIZ), where relatively small ice floes are dominant, the floe size distribution is an important parameter affecting melt processes given the larger cumulative perimeter of multiple small floes compared with a single ice floe of the same area. Smaller ice floes are therefore subject to increased lateral melt. However, the available data have been very limited so far. Analysis of sea ice in the Sea of Okhotsk revealed that while floe size distribution is basically scale invariant, a regime shift occurs at a size of about 40. m. In order to extend this preliminary result to the Antarctic MIZ and further examine the controlling factors, the first concurrent ice floe size and ice thickness measurements were conducted in the northwestern Weddell Sea and off Wilkes Land (around 64°S, 117°E) with a heli-borne digital video camera in the late winter of 2006 and 2007, respectively. The floe sizes ranged from 2 to 100. m. Our analysis shows: 1) the scale invariance and regime shift are confirmed in both regions; 2) the floe size at which regime shift occurs slightly increases from 20 to 40. m, with ice thickness, consistent with the theory of the flexural failure of sea ice; and 3) the aspect ratio is 1.6-1.9 on average, close to the previous results. Based on these results, the processes affecting the floe size distribution and the subsequent implications on melt processes are discussed. By applying a renormalization group method to interpret the scale invariance in floe size distribution, the fractal dimension is related to the fragility of sea ice. These results indicate the importance of wave-ice interaction in determining the floe size distribution. © 2010 Elsevier Ltd.
Soma M.,Hokkaido University |
Garamszegi L.Z.,CSIC - Donana Biological Station
Behavioral Ecology | Year: 2011
The theory of sexual selection predicts a relationship between male sexual traits and reproductive success. This prediction has been tested extensively using the complexity of birdsong as a model for trait elaboration. However, contradictory results have emerged. Some studies have demonstrated that males with large repertoires enjoy a reproductive advantage, whereas other studies have failed to support this prediction. To make general inferences from this mixed evidence, we quantitatively reviewed the relevant literature using a meta-analytic approach. The mean effect size for the song/mating success association was significant, but the effects were generally weak, affected by publication bias, confounded by uncontrolled variables, and differing across the traits examined. Effect sizes were heterogeneous across studies due to species-specific effects, differences in mating systems, and song phenotypes. The degree of association between song complexity and reproductive success was independent of the strength of sexual selection, as assessed by the degree of polygyny and extrapair paternity. Our results highlight the importance of considering various biological factors to understand the role of repertoires in mediating mating success in different species. © 2011 The Author.
Ohkubo S.,Osaka University |
Hirabayashi Y.,Hokkaido University
Physical Review C - Nuclear Physics | Year: 2015
The Airy structure in 16O+14C rainbow scattering is studied with an extended double-folding (EDF) model that describes all the diagonal and off-diagonal coupling potentials derived from the microscopic realistic wave functions for 16O by using a density-dependent nucleon-nucleon force. The experimental angular distributions at EL=132, 281, and 382.2 MeV are well reproduced by the calculations. By studying the energy evolution of the Airy structure, the Airy minimum around θ=76 in the angular distribution at EL=132 MeV is assigned as the second-order Airy minimum A2 in contrast to the recent literature which assigns it as the third order A3. The Airy minima in the 90 excitation function is investigated in comparison with well-known 16O+16O and 12C+12C systems. Evolution of the Airy structure into the molecular resonances with the 16O+14C cluster structure in the low-energy region around Ec.m.=30 MeV is discussed. It is predicted theoretically for the first time for a non-4NO16+14C system that Airy elephants in the 90 excitation function are present. © 2015 American Physical Society. ©2015 American Physical Society.
Koshiba M.,Hokkaido University
2014 International Topical Meeting on Microwave Photonics / the 9th Asia-Pacific Microwave Photonics Conference, MWP/APMP 2014 - Proceedings | Year: 2014
Recent progress in a single-mode multicore fiber for high-capacity long-haul space-division multiplexing (SDM) transmission is reviewed, focusing on the design issues such as crosstalk suppression, core-density improvement, and core-arrangement optimization. A few-mode multicore fiber for dense SDM transmission is also briefly described. © 2014 IEICE.
Ishizu A.,Hokkaido University
Modern rheumatology / the Japan Rheumatism Association | Year: 2010
Overproduction of interleukin (IL)-6 from synovial cells is critically involved in the pathogenesis of rheumatoid arthritis (RA). Cyclic adenosine monophosphate (AMP) response element-binding protein (CREB), a leucine zipper transcription factor, is expressed at a high level in synovial cells of patients with RA. Although CREB transactivates IL-6 expression in vascular smooth muscle cells, the relation between CREB expression and IL-6 production from arthritic synovial cells remains unclear. In this study, to determine whether CREB is implicated in IL-6 production from arthritic synovial cells, a dominant negative molecule of activation transcription factor 1 (ATF-1) was transfected into synovial cells obtained from arthritic joints of env-pX rats. These transgenic rats carrying the env-pX gene of human T-cell leukemia virus type-1 develop destructive arthritis with high titers of serum rheumatoid factor and are thus regarded as a suitable model of RA. The dominant negative ATF-1 (ATF-1DN) constitutes a heterodimer with CREB and inhibits CREB function, as CREB/ATF-1DN heterodimers no longer bind to the target sequence of CREB. We showed that transfection of ATF-1DN significantly reduced IL-6 production from arthritic synovial cells. These findings suggest that CREB is implicated in IL-6 production from synovial cells and plays an important role in RA pathogenesis.
Uchino H.,Hokkaido University
Neurosurgery | Year: 2016
BACKGROUND:: Whether additional indirect bypasses effectively contribute to revascularization in combined procedures remains unclear in patients with moyamoya disease. OBJECTIVE:: To evaluate the longitudinal changes associated with combined procedures while following up pediatric and adult patients long term and to assess whether any other clinical factors or hemodynamic parameters affected these changes to determine an optimal surgical strategy. METHODS:: We studied 58 hemispheres in 43 adults and 39 hemispheres in 26 children who underwent combined revascularization for moyamoya disease. To evaluate bypass development, we assessed the sizes of the superficial temporal artery and middle meningeal artery using magnetic resonance angiography. Multivariate analysis determined the effects of multiple variables on bypass development. RESULTS:: Indirect bypass (middle meningeal artery) development occurred in 95% and 78% of the pediatric and adult hemispheres, respectively. Of these, dual development of direct and indirect bypasses occurred in 54% of the pediatric hemispheres and in 47% of the adult hemispheres. Reciprocal superficial temporal artery regression occurred in 28% of the hemispheres during the transition from the postoperative acute phase to the chronic phase during indirect bypass development. Good indirect bypass development was associated with adult hemispheres at Suzuki stage 4 or greater (odds ratio, 7.4; 95% confidence interval, 1.4-39.4; P = .02). Disease onset type and preoperative hemodynamic parameters were not considered predictors for the development of surgical revascularization. CONCLUSION:: Simultaneous direct and indirect bypass development was most frequently observed, regardless of patient age and hemodynamic status. Applying indirect bypass as an adjunct to direct bypass could maximize revascularization in adults and children. ABBREVIATIONS:: CBF, cerebral blood flowDTA, deep temporal arteryMCA, middle cerebral arteryMMA, middle meningeal arteryMMD, moyamoya diseaseMRA, magnetic resonance angiographySPECT, single-photon emission computed tomographySTA, superficial temporal artery Copyright © by the Congress of Neurological Surgeons
Mito S.,Hokkaido University
Nihon Hoshasen Gijutsu Gakkai zasshi | Year: 2011
The purposes of this study were to determine optimum flip angles (FAs) and to compare the effectiveness of fat suppression and signal homogeneity among three techniques, spectral attenuated with inversion recovery (SPAIR), principle of selective excitation technique (PROSET), and three-point DIXON technique (DIXON), of the bilateral breast dynamic sequence acquired using the optimum FA at 3.0 T. Using a homemade phantom that represented a tumor, fat, and a mammary gland, the optimum FAs were determined from the change of fat signal intensity, signal-to-noise ratio (SNR) of the mammary gland, and contrast ratio (CR) between the tumor and mammary gland. The effectiveness of fat suppression and signal homogeneity were compared in ten breast cancer cases, using the CR between fat and pectoralis muscle signal intensities and the standard deviation (SD) of fat signal intensity, respectively. The optimum FAs for SPAIR, PROSET, and DIXON were 10, 20, and 20 degrees, respectively. The mean CR between fat and pectoralis muscle signal intensities achieved using SPAIR, PROSET, and DIXON were 0.19, 0.30 and 0.40, respectively, and the mean SDs of the fat signal intensities were 90.2, 103.1, and 30.5, respectively. The DIXON technique provided better fat suppression and signal homogeneity than the other two techniques. The results of this study suggest the possible application of the DIXON technique in combination with the optimum FA setting as an effective fat suppression technique for the bilateral breast dynamic sequence at 3.0 T.
Jinushi M.,Hokkaido University
OncoImmunology | Year: 2014
We identify novel mechanisms whereby chemoresistance enables cancer stem cells to create pro-inflammatory tumor microenvironments. Chemoresistant cancer stem cells promote M2 macrophage differentiation through interferon-regulatory factor-5 (IR F5)-and macrophage-colony stimulating factor (M-CSF)-dependent mechanisms and produce various other cell-signaling factors that together fuel inflammation-driven carcinogenesis. These findings clarify a molecular pathway linking cancer "stemness" and pro-tumor inflammation in an immunosuppressive niche. © 2014 Landes Bioscience.
Tanaka K.,Hokkaido University
Physica Status Solidi (B) Basic Research | Year: 2012
We study comparatively some characteristics of photodarkening and photoexpansion in chalcogenide glasses. In thicker samples, both grow more slowly, but the thickness variations are different. The feature can be understood with an idea that the two phenomena originate from a common atomic displacement, while the expansion in thick films suffers marked delays, due to viscous transfer of photogenerated internal stress to sample surfaces. Densities of the common atomic site are estimated at 0.5-1at.%, the situation corresponding to single isolated (uncorrelated) centres in medium-range structures, which provides the quasi-stability of illuminated states. We also discuss relations between the darkening, the expansion (density reduction), and a refractive-index increase. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Qiu J.-D.,Nanchang University |
Wang G.-C.,Nanchang University |
Liang R.-P.,Nanchang University |
Xia X.-H.,Nanjing University |
Yu H.-W.,Hokkaido University
Journal of Physical Chemistry C | Year: 2011
Platinum nanoparticles (Pt NPs) with uniform size and high dispersion have been successfully assembled on poly(diallyldimethylammonium chloride) functionalized graphene oxide via a sodium borohydride reduction process. The loading concentration of Pt NPs on graphene can be adjusted in the range of 18-78 wt %. The obtained Pt/graphene nanocomposites are characterized by transmission electron microscopy, high resolution transmission electron microscopy, energy dispersive spectrometry, X-ray diffraction, and thermogravimetric analysis. The results show that the Pt NPs with sizes of approximate 4.6 nm uniformly disperse on graphene surface for all Pt loading densities. Electrochemical studies reveal that the Pt/graphene nanocomposites with electrochemically active surface area of 141.6 m2/g show excellent electrocatalytic activity toward methanol oxidation and oxygen reduction. The present method is promising for the synthesis of high performance catalysts for fuel cells, gas phase catalysis, and sensors. © 2011 American Chemical Society.
Utsumi S.,Hokkaido University
Journal of Ecology | Year: 2015
Genetic variation in individual species can have important ecological consequences, and sometimes, these interactions are mediated through another species. For example, genetic variation in an herbivore could alter plant responses that then influence other plant-associated arthropods. However, few systems have experimentally tested the ecological consequences of genetic variation as mediated through other species, especially within the same trophic community context. I studied how evolution of feeding preference in the willow leaf beetle (Plagiodera versicolora), which occurs under selection in a herbivore community context, feeds back to an arthropod community through plant-mediated indirect interactions. Previous studies show beetle populations locally adapt distinct preferences ranging from the gourmet-type, which feeds exclusively on new leaves of willows, to the no-preference (no-pref) type, which displays non-preferential feeding on leaves of different ages. I conducted field experiments at two sites that mimicked evolutionary changes in the feeding preference of the leaf beetle. I manipulated the composition of leaf beetle feeding types for 6 days in spring and then investigated subsequent development of arthropod communities. I found that initial herbivory by a higher proportion of gourmet-type beetles led to lower subsequent abundance of conspecific beetle larvae. In contrast, a higher proportion of gourmet-type beetles resulted in higher abundance of aphids. Aphid-tending ants also increased with the increasing abundance of aphids. As a result, species diversity of arthropod communities decreased with the proportion of gourmet-type beetles in the initial beetle treatment. Community assembly dynamics were significantly influenced by interactive effects between the initial beetle treatment and subsequent colonizer species identities. Thus, beetle genetic variation had long-lasting effects through a temporal chain of indirect interactions likely mediated through induced plant responses and the abundance of aphids. Synthesis. Evolutionary changes in feeding traits within an herbivore species had profound but predictable impact on local arthropod communities. Because the feeding evolution of herbivores nearly always occurs in a community context, plant-mediated feedback loops between the evolution and ecological community of arthropods may be widespread in nature. Evolutionary changes in feeding traits within an herbivore species had profound but predictable impact on local arthropod communities. Because the feeding evolution of herbivores nearly always occurs in a community context, plant-mediated feedback loops between the evolution and ecological community of arthropods may be widespread in nature. © 2015 British Ecological Society.
Li J.,Taiyuan University of Technology |
Narita Y.,Hokkaido University
Composite Structures | Year: 2014
A design approach is presented for the multi-objective optimal design problem of aeroelastic laminated doubly curved shallow shells. The design objective is the maximization of weighted sum of the critical aerodynamic pressures under different probability density function of flow orientations. The design variable is the fiber orientations in the layers of the symmetrically angle-ply shells. Four typical probability density functions of flow orientations are considered. Hamilton's principle with the first-order shear deformation theory (FSDT) is used in the flutter analysis of supersonic doubly curved shallow shells. The multi-objective optimal design problem of symmetrical alternating angle-ply sequence [θ/-θ/θ/-θ]s and symmetrical arbitrary angle-ply sequence [θ1/θ2/θ3/θ4]s laminated shell structure are investigated. Finally, using a layerwise optimization approach (LOA), the optimal fiber orientation angles of supersonic laminated shells are determined to obtain the maximum design objective. © 2014 Elsevier Ltd.
Hara-Nishimura I.,Kyoto University |
Hatsugai N.,Hokkaido University
Cell Death and Differentiation | Year: 2011
Almost all plant cells have large vacuoles that contain both hydrolytic enzymes and a variety of defense proteins. Plants use vacuoles and vacuolar contents for programmed cell death (PCD) in two different ways: for a destructive way and for a non-destructive way. Destruction is caused by vacuolar membrane collapse, followed by the release of vacuolar hydrolytic enzymes into the cytosol, resulting in rapid and direct cell death. The destructive way is effective in the digestion of viruses proliferating in the cytosol, in susceptible cell death induced by fungal toxins, and in developmental cell death to generate integuments (seed coats) and tracheary elements. On the other hand, the non-destructive way involves fusion of the vacuolar and the plasma membrane, which allows vacuolar defense proteins to be discharged into the extracellular space where the bacteria proliferate. Membrane fusion, which is normally suppressed, was triggered in a proteasome-dependent manner. Intriguingly, both ways use enzymes with caspase-like activity; the membrane-fusion system uses proteasome subunit PBA1 with caspase-3-like activity, and the vacuolar-collapse system uses vacuolar processing enzyme (VPE) with caspase-1-like activity. This review summarizes two different ways of vacuole-mediated PCD and discusses how plants use them to attack pathogens that invade unexpectedly. © 2011 Macmillan Publishers Limited All rights reserved.
Takahashi T.,Hokkaido University
Neuroendocrinology Letters | Year: 2011
Neuroeconomic conditions for "rational addiction" (Becker & Murphy 1988) have been unknown. This paper derived the conditions for "rational addiction" by utilizing a nonlinear time-perception theory of "hyperbolic" discounting, which is mathematically equivalent to the q-exponential intertemporal choice model based on Tsallis' statistics. It is shown that (i) Arrow-Pratt measure for temporal cognition corresponds to the degree of irrationality (i.e., Prelec's "decreasing impatience" parameter of temporal discounting) and (ii) rationality in addicts is controlled by a nondimensionalization parameter of the logarithmic time-perception function. Furthermore, the present theory illustrates the possibility that addictive drugs increase impulsivity via dopaminergic neuroadaptation without increasing irrationality. Future directions in the application of the model to studies in neuroeconomics are discussed. © 2011 Neuroendocrinology Letters.
Kasai K.,Hokkaido University
The International journal of oral & maxillofacial implants | Year: 2012
The purpose of this study was to investigate the influence of occlusal forces (the contractile forces of the masticatory muscles) during occlusal adjustment on the distribution of forces on combinations of implants and teeth during intercuspal clenching by means of finite element analysis. Three-dimensional finite element models of the mandible, one with two implants in the molar region and the other with four implants in the premolar and molar regions, were constructed. Linearly elastic material properties were defined for all elements except the periodontal ligament, which was defined as nonlinearly elastic. The temporomandibular joints and antagonists were simplified and replaced with nonlinear springs. Antagonists were assumed to be a natural tooth or an implant and had two- or three-stage displaceability (ie, very high displaceability under tension and when the displacement was smaller than the clearance assumed to be made by occlusal adjustment, but displaceability of the antagonists themselves when the displacement was greater than the clearance). The clearance by occlusal adjustment was decided beforehand with a trial-and-error method so that the occlusal forces were distributed symmetrically under a prescribed load. Each model was evaluated under loads of 100 N, 200 N, and 800 N for the distribution of occlusal forces on the teeth and implants. In the case of occlusal adjustment under the total occlusal force of 40 N, the stress was concentrated at the most posteriorly located implant in all models under all loading conditions. This concentration was reduced in the case of occlusal adjustment under the total occlusal force of 200 N, except under a load of 800 N. Hard biting appeared to be better for occlusal adjustment to avoid overloading of the most posterior implant.
Wang L.,Dalian University of Technology |
Ueda T.,Hokkaido University
Ocean Engineering | Year: 2011
Water penetration into concrete by capillary absorption plays a very important role in the ingress of contaminative substances when the structures are built in aggressive environments. In the present paper the lattice network model is proposed based on the unsaturated flow theory to predict the water penetration into concrete. On the mesocale level, concrete is treated as a three-phase composite. By means of the Voronoi diagram meshing strategy, the lattice network model of concrete with different types of lattice elements is developed. The corresponding transport properties are assigned to the lattice elements in the network falling in different phases. As a result, the lattice elements are idealized as conductive "pipes" in which uni-directional flow can be realized between the two nodes of the elements. Parameters in the lattice network model, such as the sorptivity and porosity of the mortar and the ITZs are quantitatively determined. With help of the approach, the water content distribution within a concrete sample after any elapsed time, especially the penetration depth of water frontier, can be easily predicted. The cumulative water absorption calculated by the lattice network model is shown to be well agreed with the experimental results. © 2011 Elsevier Ltd.
Sabe H.,Hokkaido University
Journal of Biochemistry | Year: 2011
Contrary to the long believed hypothesis, it is now evident that breast cancer cells can disseminate from the early phases of the oncogenesis; and that such early disseminated cells sometimes survive at the sites of dissemination and may outgrow after a long latency of years and decades. For cancer cells to leave their origin, they must at least transiently loosen their adhesion with adjacent epithelial cells and stroma, and become motile while avoiding anoikis. Such processes resemble epithelial-mesenchymal transdifferentiation (EMT), which normally takes place in situations such as embryogenesis and wound healing. Interestingly, the occurrence of an EMT-like process in breast cancer cells has been implicated in the generation of cancer stem-like cells, in which TGFβ1 signalling often plays core roles. Here, I discuss the current knowledge regarding cancerous EMT and its signalling pathways with the aim to consider the possible mechanisms of early dissemination, and also the generation of cancer stem-like cells in mammary tumour. © The Authors 2011. Published by Oxford University Press on behalf of the Japanese Biochemical Society. All rights reserved.
Matsuhashi T.,Hokkaido University
Hand surgery : an international journal devoted to hand and upper limb surgery and related research : journal of the Asia-Pacific Federation of Societies for Surgery of the Hand | Year: 2011
We have carried out a replacement of the lunate in 12 patients with advanced Kienböck's disease, with excision of the lunate and insertion of an iliac bone flap wrapped into palmaris longus. The aims of this study were to determine the effect of this procedure for advanced Kienböck's disease. At a mean follow-up period of 45.3 months, the mean clinical score was excellent in all cases. Radiographically, progression of osteoarthritis (OA) in the radiocarpal joint was found in two patients. At follow-up, the X-ray findings indicated a reduced of osseous core in four patients. On the other hand, carpal height ratio showed no significant change at follow-up. Excision arthroplasty using a tendon ball with osseous core for advanced Kienböck's disease leads to OA progression in some cases. However, clinical results were excellent in all cases. Therefore, this current study provides effective therapeutic procedure for advanced Kienböck's disease.
Mayama H.,Hokkaido University |
Nonomura Y.,Yamagata University
Langmuir | Year: 2011
Wetting on a cylindrical pillar defect is discussed in terms of the free-energy difference ΔG. Wetting is divided into wetting on a flat surface, a pinning effect at the apex of the defect, and wetting on a pillar wall. First, we confirmed that ΔG between before and after ideal wetting on a flat surface can be derived as a function of the contact angle θ in which the free-energy minimum is obtained as the equilibrium contact angle θ eq described by Young's and Wenzel's laws. Second, the pinning effect at the apex in the cross section of the pillar defect is discussed in ΔG, where the pinning effect is shown to originate from the energy barrier by an increase in the air-liquid interfacial area of a pinned droplet induced by deformation. Next, the ΔG profiles of wetting on the pillar wall are drawn based on the theory of Carroll (Carroll, B. J. J. Colloid Interface Sci.1976, 57, 488-495) to better understand the ΔG profile during penetration. Differences in the manner of wetting between the wetting state on a flat surface and the pillar wall are reflected in ΔG. Finally, penetration of a droplet into a pillar defect is comprehensively discussed on the basis of wetting on a flat surface and a pillar wall. If we consider a simple manner of penetration, another type of energy barrier resulting from an anomalous deformation of the air-liquid interface of the penetrating droplet can be theoretically suggested. Consequently, two types of energy barrier are found. These energy barriers should play a significant role in the hysteresis of wetting, the liquid-repellent Cassie-Baxter state (CB), and the CB-Wenzel wetting transition on a microtextured surface. © 2011 American Chemical Society.
Fusetani N.,Hokkaido University
Natural Product Reports | Year: 2011
In this review, antifouling metabolites of marine bacteria and fungi, seaweeds, aquatic plants, and marine invertebrates are described. Also included are marine natural products that induce larval settlement, as well as those inhibiting bacterial quorum sensing and larval settlement. © 2011 The Royal Society of Chemistry.
Urano A.,Hokkaido University |
Ando H.,Kyushu University
General and Comparative Endocrinology | Year: 2011
The hypothalamic neurosecretory cells (NSCs) which produce and release neurohypophysial hormones are involved in controls of diverse physiological phenomena including homeostatic controls of unconscious functions and reproduction. The far and wide distribution of neurosecretory processes in the discrete brain loci and the neurohypophysis is appropriate for coordination of neural and endocrine events that are required for the functions of NSCs. The presence of dye couplings and intimate contacts among NSCs supports harmonious production and release of hormone to maintain the plasma level within a certain range which is adequate for a particular physiological condition. Neurosecretory cells integrate diverse input signals from internal and external sources that define this particular physiological condition, although reactions of NSCs vary among different species, and among different cell types. An input signal to NSC is received by specific receptors and transduced as unique intracellular signals, important for the various functions of neurohypophysial hormones. Orchestration of multiple intracellular signaling systems, activities of which are individually modulated by input signals, determines the rates of synthesis and release of hormone through regulation of gene expression. The first step of gene expression, i.e., transcription, is amenable for diverse reaction of NSCs, because the 5′ upstream regions of genes encoding neurohypophysial hormones are highly variable. © 2010 Elsevier Inc.
Yoshizawa K.,Hokkaido University
Physics of the Earth and Planetary Interiors | Year: 2014
A new radially anisotropic shear wave speed model for the Australasian region is constructed from multi-mode phase dispersion of Love and Rayleigh waves. An automated waveform fitting technique based on a global optimization with the Neighbourhood Algorithm allows the exploitation of large numbers of three-component broad-band seismograms to extract path-specific dispersion curves covering the entire continent. A 3-D shear wave model is constructed including radial anisotropy from a set of multi-mode phase speed maps for both Love and Rayleigh waves. These maps are derived from an iterative inversion scheme incorporating the effects of ray-path bending due to lateral heterogeneity, as well as the finite frequency of the surface waves for each mode. The new S wave speed model exhibits major tectonic features of this region that are in good agreement with earlier shear wave models derived primarily from Rayleigh waves. The lateral variations of depth and thickness of the lithosphere-asthenosphere transition (LAT) are estimated from the isotropic (Voigt average) S wave speed model and its vertical gradient, which reveals correlations between the lateral variations of the LAT and radial anisotropy. The thickness of the LAT is very large beneath the Archean cratons in western Australia, whereas that in south Australia is thinner. The radial anisotropy model shows faster SH wave speed than SV beneath eastern Australia and the Coral Sea at the lithospheric depth. The faster SH anomaly in the lithosphere is also seen in the suture zone between the three cratonic blocks of Australia. One of the most conspicuous features of fast SH anisotropy is found in the asthenosphere beneath the central Australia, suggesting anisotropy induced by shear flow in the asthenosphere beneath the fast drifting Australian continent. © 2014 Elsevier B.V.