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Sendai, Japan

Tohoku University , Tōhoku daigaku), abbreviated to Tohokudai , located in Sendai, Miyagi in the Tōhoku Region, Japan, is a Japanese national university. It is the third oldest Imperial University in Japan and among the National Seven Universities. It is considered as one of the most prestigious universities in Japan, and one of the top fifty universities in the world.In 2009, Tohoku University had ten colleges within the university, including fifteen departments with graduate students, with a total enrollment of 17,949 students. The university's three core values are "Research First ," "Open-Door ," and "Practice-Oriented Research and Education ." Wikipedia.

Wilks A.,University of Maryland, Baltimore | Ikeda-Saito M.,Tohoku University
Accounts of Chemical Research | Year: 2014

ConspectusThe eukaryotic heme oxygenases (HOs) (E.C. convert heme to biliverdin, iron, and carbon monoxide (CO) in three successive oxygenation steps. Pathogenic bacteria require iron for survival and infection. Extracellular heme uptake from the host plays a critical role in iron acquisition and virulence. In the past decade, several HOs required for the release of iron from extracellular heme have been identified in pathogenic bacteria, including Corynebacterium diphtheriae, Neisseriae meningitides, and Pseudomonas aeruginosa. The bacterial enzymes were shown to be structurally and mechanistically similar to those of the canonical eukaryotic HO enzymes. However, the recent discovery of the structurally and mechanistically distinct noncanonical heme oxygenases of Staphylococcus aureus and Mycobacterium tuberculosis has expanded the reaction manifold of heme degradation. The distinct ferredoxin-like structural fold and extreme heme ruffling are proposed to give rise to the alternate heme degradation products in the S. aureus and M. tuberculosis enzymes. In addition, several "heme-degrading factors" with no structural homology to either class of HOs have recently been reported. The identification of these "heme-degrading proteins" has largely been determined on the basis of in vitro heme degradation assays. Many of these proteins were reported to produce biliverdin, although no extensive characterization of the products was performed. Prior to the characterization of the canonical HO enzymes, the nonenzymatic degradation of heme and heme proteins in the presence of a reductant such as ascorbate or hydrazine, a reaction termed "coupled oxidation", served as a model for biological heme degradation. However, it was recognized that there were important mechanistic differences between the so-called coupled oxidation of heme proteins and enzymatic heme oxygenation. In the coupled oxidation reaction, the final product, verdoheme, can readily be converted to biliverdin under hydrolytic conditions. The differences between heme oxygenation by the canonical and noncanonical HOs and coupled oxidation will be discussed in the context of the stabilization of the reactive FeIII-OOH intermediate and regioselective heme hydroxylation. Thus, in the determination of heme oxygenase activity in vitro, it is important to ensure that the reaction proceeds through successive oxygenation steps. We further suggest that when bacterial heme degradation is being characterized, a systems biology approach combining genetics, mechanistic enzymology, and metabolite profiling should be undertaken. © 2014 American Chemical Society. Source

The donor/acceptor ionic chain (i.e., the D+A- chain) [Ru2(2-MeO-4-ClPhCO2)4(BTDA-TCNQ)]·2. 5(benzene) (1; 2-MeO-4-ClPhCO2- = 2-methoxy-4- chlorobenzoate; BTDA-TCNQ = bis(1,2,5-thiadiazolo)tetracyanoquinodimethane) is a ferrimagnetic chain with S = 3/2 from [Ru2II,III] + (i.e., D+) and S = 1/2 from BTDA-TCNQ•- (i.e., A-), with J ≈ -100 K, in which long-range antiferromagnetic ordering at TN = 11 K occurs because interchain antiferromagnetic interactions are critical. Compound 1 undergoes a reversible crystal-to-crystal structural transformation with the elimination/absorption of the crystallization solvent to form the dried compound [Ru2(2-MeO-4-ClPhCO 2)4(BTDA-TCNQ)] (1′), which has a higher T N (14 K). This change is clearly caused by the shortening of the interchain distances because the exchange coupling parameter for the chain is the same in both 1 and 1′. The chain compounds in 1 can be doped with minor diamagnetic [Rh2II,II] species, [{(Ru 2)1-x(Rh2)x(2-MeO-4-ClPhCO 2)4}(BTDA-TCNQ)]·2.5(benzene) (x = 0.03 for Rh-3%; x = 0.05 for Rh-5%; x = 0.16 for Rh-16%), which shifts the TN to lower temperatures, the magnitude of the shift being dependent on the doping ratio x (TN = 5.9 K for Rh-3%, TN = 3.7 K for Rh-5%, and TN was not observed above 1.8 K for Rh-16%). Drying a doped compound increased its TN, as was found for 1′: TN = 9.9 K for Rh-3%′, TN = 9.2 K for Rh-5%′, and TN was not observed above 1.8 K for Rh-16%′. TN had a linear relationship with the doping ratio x of the [Rh2] species in both the fresh and dried compounds. The TN linear relationship is associated with the magnitude of the effective magnetic dipole (i.e., the average correlation length) in the chains caused by the [Rh2] defects as well as naturally generated defects in the synthetic process and with the interchain distances affected by the crystal-to-crystal transformations. These results demonstrate that slightly modifying the short-range correlation lengths, which changes the magnetic dipole magnitudes, strongly affects the bulk antiferromagnetic transition, with key dipole-dipole interactions, in low-dimensional anisotropic systems. © 2014 American Chemical Society. Source

Ide H.,Tohoku University
Developmental Dynamics | Year: 2012

Background: Although urodela amphibians completely regenerate amputated limbs, the potency of limb regeneration in mammalians is very low. In mice and humans, a digit tip regenerates, but no regeneration beyond the digit joint occurs. In this article, we describe the induction of bone formation by BMPs in the forearm, a more proximal region, of neonatal mice. Distal halves of the radius and ulna were removed from limbs amputated at the wrist level in advance, and gelatin rods containing BMPs were grafted in the space of the forearm. BMP-7 and BMP-2 were effective. Results: The induction of bone formation depended on the amount of BMP-7 in grafted gelatin gels. BMP-7 at over 320 ng/limb induced long bones within 10 days. Cartilage formation was always observed before the bone formation as in the case of normal limb development. The origin of cells responsive to BMP-7 is not clear, but the formation of large bone tissues in a relatively short time suggests a wide distribution of precursor cells in the limbs. Grafting of dye-stained mesenchymal tissue fragments suggested that mesenchymal tissues other than the dermis, bone, and joint cartilage are responsive to BMP-7 and form cartilage/bone. Two long bones induced were arranged in parallel fashion in many cases like the radius and ulna. An agonist of hedgehog promoted the formation of bones in the presence of BMP-7. Furthermore, bone elements were fused to stump bones to form a single bone. Conclusions: The results suggest the potency of bone pattern regeneration in the amputated forearm of a neonatal mouse. © 2012 Wiley Periodicals, Inc. Source

Terada M.,Tohoku University
Current Organic Chemistry | Year: 2011

Chiral phosphoric acids derived from axially chiral biaryls and analogous chiral Brønsted acids have emerged as an attractive and widely applicable class of enantioselective organocatalysts for a variety of organic transformations. In this account article, we review our recent achievements and related works in the development of enantioselective carbon-carbon bond forming reactions using these axially chiral phosphoric acids and their analogues as chiral Brønsted acid catalysts. The contents are arranged according to the type of (pro)electrophiles, including imines, hemiaminal ethers, carbonyl compounds, and electron-rich double bonds, followed by specific reaction types. Further application to phosphoric acid/metal complex-combined catalytic systems is also highlighted. © 2011 Bentham Science Publishers Ltd. Source

Oikawa H.,Tohoku University
Bulletin of the Chemical Society of Japan | Year: 2011

Organic nanocrystals (NCs) are in the mesoscopic phase between a single molecule and the corresponding bulk crystals, and are expected to exhibit peculiar optical properties, depending on crystal size and shape. In the present Award Accounts, recent progress on hybridized organic NCs and ordered array structure of encapsulated organic NCs will be introduced in detail for optically functional materials toward next-generation organic device application. Hybrid material (or hybridization) is an important area in current material science. Our attention is now focused on coreshell type hybridized organic NCs, which seem to be the best suited nanostructure for providing novel optoelectronic properties and photonic function induced by coreshell interface interaction. On the other hand, it may be necessary to arrange and integrate organic NCs, including hybridized materials, on a substrate so as to receive and transmit input and output signals by electronically and/or optically accessing organic devices. Hence, encapsulations of organic NCs, patterned substrates, and tapered cell method have been employed suitably to fabricate and control ordered array structure of organic NCs on a substrate. Finally, the future scope in the relevant fields of optoelectronics and photonics will be discussed in brief.© 2011 The Chemical Society of Japan. Source

I developed a gametophytic self-incompatibility (SI) model to study the conditions leading to diversification in SI haplotypes. In the model, the SI system is assumed to be incomplete, and the pollen expressing a given specificity is not fully rejected by the pistils expressing the same specificity. I also assumed that mutations can occur that enhance the rejection of pollen by pistils with the same haplotype variant and reduce rejection by pistils with other variants in the same haplotype. I found that if such mutations occur, the new haplotypes (mutant variants) can stably coexist with the ancestral haplotype in which the mutant arose. This is because pollen bearing the new haplotype is most strongly rejected by pistils bearing the same new haplotype among the pistils in the population; hence, negative frequency-dependent selection prevents their fixation. I also performed simulations and found that the nearly complete SI system evolves from completely self-compatible populations and that SI haplotypes can increase to about 40–50 within a few thousand generations. On the basis of my findings, I propose that diversification of SI haplotypes occurred during the evolution of SI from self-compatibility. © 2016 by The University of Chicago. All rights reserved. Source

Otsuki J.,Tohoku University
Physical Review Letters | Year: 2015

The Kondo lattice model describes a quantum phase transition between the antiferromagnetic state and heavy-fermion states. Applying the dual-fermion approach, we explore possible superconductivities emerging due to the critical antiferromagnetic fluctuations. The d-wave pairing is found to be the leading instability only in the weak-coupling regime. As the coupling is increased, we observe a change of the pairing symmetry into a p-wave spin-singlet pairing. The competing superconductivities are ascribed to crossover between small and large Fermi surfaces, which occurs with the formation of heavy quasiparticles. © 2015 American Physical Society. © 2015 American Physical Society. Source

Ohtsu A.,Tohoku University
Optics Communications | Year: 2010

The author investigated second-harmonic (SH) wave patterns generated by focused vortex beams with radial and azimuthal polarizations. Expressions for electric field components near the focus through a dielectric interface were obtained based on vector diffraction theory. Furthermore, the (110) and (001) planes of a crystal classified in the symmetry group 4? Source

Soyama H.,Tohoku University
Journal of Fluids Engineering, Transactions of the ASME | Year: 2011

In order to enhance the aggressive intensity of a cavitating jet for practical applications, the effect of the geometry of the nozzle through which the jet is driven on the aggressive intensity was investigated. The nozzle under test was cylindrical and consisted of a plate and a cap with a hole bored through it. The aggressive intensity of the jet was estimated by the erosion suffered by pure aluminum test specimens. The parameters varied were the bore diameter, D, and length, L, the standoff distance, the nozzle throat diameter, d, and the upstream and downstream pressures of the nozzle. The mass loss at the optimum standoff distance, where the mass loss was at a relative maximum, was found for each bore diameter and length, and then the optimum bore diameter and length were obtained. The optimum ratio of d: D: L was shown to be 1: 8: 8, and this was the optimum for both d = 1 mm and d = 2 mm. It was also the optimum ratio for upstream pressures of 15 MPa and 30 MPa, and downstream pressures of 0.1 MPa and 0.42 MPa. © 2011 American Society of Mechanical Engineers. Source

Fukasawa Y.,Tohoku University
Forest Ecology and Management | Year: 2012

Although decomposer fungi have been recognized to play important roles in forest carbon and nutrient cycling as well as soil humus formation, their effects on forest dynamics, such as tree regeneration, are far less well understood than the effects of symbiotic and pathogenic fungi. In this study, I focused on tree regeneration on fallen woody debris, " nurse logs" I examined the effects of wood decomposer fungi on species composition and population densities of tree seedlings (height <50. cm) established on these logs. In an abandoned tract of coppice forest in Honshu, Japan, a thick litter layer had accumulated on the forest floor and seedlings of the small-seeded pioneer tree species Clethra barbinervis (Ericales) were found to be preferentially established on rotting fallen logs of the Japanese red pine Pinus densiflora. C. barbinervis seedling establishment was considerably reduced on soil probably because there were impediments to colonization on the ground, such as the thick litter layer, which was less well developed on logs. In contrast, larger-seeded species such as Aphananthe aspera, Carpinus spp., Quercus serrata, and Rhus trichocarpa preferentially established on soil. Characteristics of wood decomposition by fungi varied among logs, and this variability significantly influenced C. barbinervis seedling density. Seedling density was significantly higher on brown-rotted logs than that on logs belonging to other decay types. Wood pH was lower in brown-rotted logs than that in logs belonging to other decay types and was negatively correlated with seedling density. Thus, pine coarse woody debris and the functional diversity of wood inhabiting fungi influence the establishment of diverse tree seedlings in this abandoned Japanese coppice forest. © 2011 Elsevier B.V. Source

Lee U.,Tohoku University
Monthly Notices of the Royal Astronomical Society | Year: 2014

We discuss non-radial modes in mass-accreting and rapidly rotating neutron stars for the coherent frequency detected in a millisecond X-ray pulsar XTE J1751-305. The spin frequency of the pulsar is νspin ≅ 435Hz and the identified frequency is νosc = 0.572 7595 × νspin. Assuming that the frequency detected is that in the corotating frame of the star, we examine r and g modes in the surface layer of accreting matter composed mostly of helium, inertial and r modes in the fluid core, and toroidal modes in the solid crust. We find that the r modes of ľ = m = 1 and 2 excited by ε-mechanism in the surface layer can give the ratio κ = νosc/νspin ≃ 0.57 at νspin = 435Hz, where m and ľ are the azimuthal wavenumber and the harmonic degree of the modes. We also suggest a toroidal crust mode and a core r mode destabilized by gravitational wave emission for the observed ratio κ. We find that the amplitude of the core r mode of ľ = m = 2 can be amplified at the surface layer by a large factor famp ∼ 102 at νspin = 435Hz for a M = 1.4M⊙ neutron-star model. This amplification, however, may not be large enough for the r-mode amplitude to be consistent with an estimation byMahmoodifar & Strohmayer (2013). Source

Sato Y.,Tohoku University
Vascular Pharmacology | Year: 2012

Angiogenesis is thought to be regulated by the local balance between angiogenesis stimulators and angiogenesis inhibitors. A number of endogenous regulators of angiogenesis have been found in the body. We recently isolated vasohibin-1 (VASH1) as a negative feedback regulator of angiogenesis produced by endothelial cells, and VASH2 as a homologue of VASH1 thereafter. We found that VASH1 was expressed in endothelial cells to terminate angiogenesis, whereas VASH2 promoted angiogenesis, in the mouse model of angiogenesis. This mini-review will focus on the vasohibin family in relation to the regulation of angiogenesis. © 2012 Elsevier Inc. Source

So T.,Tohoku University | Croft M.,La Jolla Institute for Allergy and Immunology
Frontiers in Immunology | Year: 2013

Activation of phosphoinositide 3-kinase (PI3K) and Akt (protein kinase B) is a common response triggered by a range of membrane-bound receptors on many cell types. In T lymphocytes, the PI3K-Akt pathway promotes clonal expansion, differentiation, and survival of effector cells and suppresses the generation of regulatory T cells. PI3K activation is tightly controlled by signals through the T cell receptor (TCR) and the co-stimulatory receptor CD28, however sustained and periodic signals from additional co-receptors are now being recognized as critical contributors to the activation of this pathway. Accumulating evidence suggests that many members of the Tumor Necrosis Factor receptor (TNFR) superfamily, TNFR2 (TNFRSF1B), OX40 (TNFRSF4), 4-1BB (TNFRSF9), HVEM (TNFRSF14), and DR3 (TNFRSF25), that are constitutive or inducible on T cells, can directly or indirectly promote activity in the PI3K-Akt pathway. We discuss recent data which suggests that ligation of one TNFR family molecule organizes a signalosome, via TNFR-associated factor (TRAF) adapter proteins in T cell membrane lipid microdomains, that results in the subsequent accumulation of highly concentrated depots of PI3K and Akt in close proximity to TCR signaling units. We propose this may be a generalizable mechanism applicable to other TNFR family molecules that will result in a quantitative contribution of these signalosomes to enhancing and sustaining PI3K and Akt activation triggered by the TCR. We also review data that other TNFR molecules, such as CD40 (TNFRSF5), RANK (TNFRSF11A), FN14 (TNFRSF12A), TACI (TNFRSF13B), BAFFR (TNFRSF13C), and NGFR (TNFRSF16), contribute to the activation of this pathway in diverse cell types through a similar ability to recruit PI3K or Akt into their signaling complexes. © 2013 So and Croft. Source

Akiyama S.,Tohoku University
The Tohoku journal of experimental medicine | Year: 2010

Maternal circadian information has been reported to play an important role in fetal physiology and development. Hormones and nutrition have been mainly investigated as circadian cues from mother to fetus. However, the influences of circadian properties of the pregnant reproductive organs on fetuses have not been fully investigated. To gain an insight on the circadian functions of the reproductive organs, we examined molecular clocks in the pregnant rat uterus and placenta. By using a Period1-luciferase (Per1-luc) rat, whose tissues express luciferase corresponding to activation of Period1, a "key clock gene", we examined the uterus clock during non-pregnancy, on embryonic day 12 (E12), and on E22 (the end of pregnancy) in a light-dark (LD) cycle and constant darkness (DD). By in situ hybridization we further explored Per1 mRNA rhythms in the placenta on E12 and E22. The uterus in vitro showed clear circadian Per1-luc rhythms both in and out of pregnancy, having peaks at around the time corresponding to dusk in LD. Likewise, in DD, the uterus in vitro had the same Per1-luc rhythms. The decidua in LD showed circadian Per1 mRNA rhythms, peaking during night 6 h after dusk, while the decidua in DD showed the same Per1 mRNA rhythms only on E22. In contrast, the labyrinth showed no circadian Per1 mRNA rhythms in LD or DD during pregnancy. These results suggest that the uterus and decidua, a maternally-originated tissue of the placenta, but not the labyrinth, a fetus-originated tissue of the placenta, can provide the fetus with circadian information. Source

Masamune A.,Tohoku University
Tohoku Journal of Experimental Medicine | Year: 2014

Chronic pancreatitis is a progressive infammatory disease in which pancreatic secretory parenchyma is destroyed and replaced by fbrous tissue, eventually leading to malnutrition and diabetes. Alcohol is the leading cause in Western countries, but genetic factors are also implicated. Since the identification of mutations in the cationic trypsinogen (PRSS1) gene as a cause of hereditary pancreatitis in 1996, we have seen great progress in our understanding of the genetics of pancreatitis. It has been established that mutations in the genes related to the activation and inactivation of trypsin(ogen) such as PRSS1, serine protease inhibitor Kazal type 1 (SPINK1) and chymotrypsin C (CTRC) genes are associated with pancreatitis. In 2013, carboxypeptidase A1 (CPA1) was identified as a novel pancreatitis susceptibility gene. Endoplasmic reticulum stress in pancreatic acinar cells resulting from the mis-folding of mutated pancreatic enzymes has been shown to act as a novel mechanism underlying the susceptibility to pancreatitis. In Japan, the nationwide survey revealed 171 patients (96 males and 75 females) with hereditary pancreatitis in 59 families based on the European Registry of Hereditary Pancreatitis and Familial Pancreatic Cancer criteria. Because about 30% of families with hereditary pancreatitis do not carry mutations in any of the known pancreatitis susceptibility genes, other yet unidentified genes might be involved. Next generation sequencers can perform billions of sequencing reactions with a read length of 150-250 nucleotides. Comprehensive analysis using next generation sequencers will be a promising strategy to identify novel pancreatitis-associated genes and further clarify the pathogenesis of pancreatitis. © 2014 Tohoku University Medical Press. Source

Autophagy is a bulk degradation system in all eukaryotic cells and regulates a variety of biological activities in higher eukaryotes. Recently involvement of autophagy in the regulation of the secretory pathway has also been reported, but the molecular mechanism linking autophagy with the secretory pathway remains largely unknown. Here we show that Atg16L1, an essential protein for canonical autophagy, is localized on hormone-containing dense-core vesicles in neuroendocrine PC12 cells and that knockdown of Atg16L1 causes a dramatic reduction in the level of hormone secretion independently of autophagic activity. We also find that Atg16L1 interacts with the small GTPase Rab33A and that this interaction is required for the dense-core vesicle localization of Atg16L1 in PC12 cells. Our findings indicate that Atg16L1 regulates not only autophagy in all cell types, but also secretion from dense-core vesicles, presumably by acting as a Rab33A effector, in particular cell types. Source

Matsumoto Y.,Tohoku University
Circulation Journal | Year: 2013

The Annual Congress of the European Society of Cardiology (ESC) was held in Amsterdam from the 31st of August to the 4th of September 2013. The total attendance up to the 3rd was 29,990. Several important topics were presented and discussed, including a randomized trial of preventive angioplasty in myocardial infarction (PRAMI), transcatheter aortic valve implantation, renal denervation, management of vasospastic angina, plaque vulnerability and outcome assessed by OCT and diuretic resistance in heart failure (an ESC-JCS [Japanese Circulation Society] joint session), and OCT-guided percutaneous coronary intervention. The ESC congress has become one of the most important and attractive international scientific meetings. Importantly, Japan topped the number of abstracts submitted (1,459 abstracts) and accepted (565 abstracts) to ESC 2013. Thus, the ESC is eager to continue the strong collaboration with the JCS as the relationship between them gets closer year by year. Source

Rikiishi H.,Tohoku University
Cancer Biology and Therapy | Year: 2012

The survival rates of patients with squamous cell carcinoma of the head and neck (HNSCC) have not improved significantly despite multi-modality therapy, including surgery, radiation therapy and chemotherapy. Recently, molecular targeted agents have shown significant improvement in clinical outcomes; for example, in chronic myelogeneous leukemia with imatinib, breast cancer with trastuzumab, colon cancer with bevacizumab and cetuximab, and renal cell cancer with sorafenib and sunitinib. In HNSCC, the epidermal growth factor receptor antibody cetuximab has shown promising results in combination with radiation. Targeted agents including cetuximab induce stresses to activate prosurvival autophagy. Combining autophagy inhibitors with agents that induce autophagy as a prosurvival response may therefore increase their therapeutic efficacy. Whether autophagy contributes to the prosurvival response or to the antitumor effect of chemotherapeutic drugs is largely unknown. This review will discuss the possible role of autophagy as a novel target for anticancer therapy agents in HNSCC. © 2012 Landes Bioscience. Source

Makino T.,Trinity College Dublin | Makino T.,Tohoku University | McLysaght A.,Trinity College Dublin
Genome Research | Year: 2012

Whole genome duplication (WGD) has made a significant contribution to many eukaryotic genomes including yeast, plants, and vertebrates. Following WGD, some ohnologs (WGD paralogs) remain in the genome arranged in blocks of conserved gene order and content (paralogons). However, the most common outcome is loss of one of the ohnolog pair. It is unclear what factors, if any, govern gene loss from paralogons. Recent studies have reported physical clustering (genetic linkage) of functionally linked (interacting) genes in the human genome and propose a biological significance for the clustering of interacting genes such as coexpression or preservation of epistatic interactions. Here we conduct a novel test of a hypothesis that functionally linked genes in the same paralogon are preferentially retained in cis after WGD. We compare the number of protein-protein interactions (PPIs) between linked singletons within a paralogon (defined as cis-PPIs) with that of PPIs between singletons across paralogon pairs (defined as trans-PPIs).Wefind that paralogons in which the number of cis-PPIs is greater than that of trans-PPIs are significantly enriched in human and yeast. The trend is similar in plants, but it is difficult to assess statistical significance due to multiple, overlapping WGD events. Interestingly, human singletons participating in cis-PPIs tend to be classified into "response to stimulus." We uncover strong evidence of biased gene loss after WGD, which further supports the hypothesis of biologically significant gene clusters in eukaryotic genomes. These observations give us new insight for understanding the evolution of genome structure and of protein interaction networks. © 2012, Published by Cold Spring Harbor Laboratory Press. Source

Gleadall I.G.,Tohoku University
Journal of Experimental Marine Biology and Ecology | Year: 2013

Molecular sequencing of nuclear and mitochondrial genes of inkless octopuses in the genus Muusoctopus (Cephalopoda: Octopodidae) has revealed that, although widely distributed, the component species are all closely related. However, a better understanding of this group has been hindered by the lack of molecular sequence data for the type species, M. januarii (Hoyle, 1885b), and an apparently fragmented pattern of distribution, with some very closely related species extant in physically separated benthic areas such as the northeastern Atlantic and northeastern Pacific. Based on morphometric and meristic data, M. januarii (from the western Atlantic) is here identified as synonymous with M. normani (Massy, 1907; type locality in the northeastern Atlantic to the south west of the British Isles). This is in agreement with a suggestion in the early 1990's that M. januarii is an amphi-Atlantic species. It is therefore here proposed that sequence data from M. normani can be used as a proxy for M. januarii. It is also proposed that the ancestors of M. januarii walked through the Atrato Seaway into the Atlantic before the rise and completion of the Panamanian Isthmus; and that M. longibrachus (Ibáñez, Sepúlveda and Chong, 2006) was separated into two allopatric populations around the time of the Last Glacial Maximum to form the dichopatric pair of subspecies now extant in the Magellan Region off southern South America. The timing of these two vicariance events provides a means of calibrating the recent divergence rate in the Muusoctopus group, which appears to be at least two to three times faster than reported previously. © 2013 Elsevier B.V. Source

Tsunekawa Y.,Scripps Research Institute | Osumi N.,Tohoku University
Cell Cycle | Year: 2012

It has long been argued that cell cycle regulators such as cyclins, cyclin-dependent kinases and their inhibitors affect the fate of neuronal progenitor cells. Recently, we identified that cyclin D2, which localizes at the basal tip of the radial glial cell (i.e., the neural progenitor in the developing neocortex), functions to give differential cell fates to its daughter cells just after cell division. This basally biased localization is due to transportation of cyclin D2 mRNA via its unique cis-regulatory sequence and local translation into cyclin D2 protein at the basal endfoot. During division of the neural progenitor cells, cyclin D2 protein is inherited by the daughter cell that retain the basal process, resulting in asymmetric distribution of cyclin D2 protein between the two daughter cells. Cyclin D2 is similarly localized in the human fetal cortical primordium, suggesting a common mechanism for the maintenance of neural progenitors and a possible scenario in evolution of primate brains. Here we introduce our recent findings and discuss how cyclin D2 functions in mammalian brain development and evolution. © 2012 Landes Bioscience. Source

Chronic obstructive pulmonary disease (COPD) is becoming a major cause of death worldwide. COPD is characterized by a progressive and not fully reversible airflow limitation caused by chronic small airway disease and lung parenchymal destruction. Clinically available drugs improve airflow obstruction and respiratory symptoms but cannot cure the disease. Slowing the progressive lung destruction or rebuilding the destroyed lung structure is a promising strategy to cure COPD. In contrast to small animal models, pharmacological lung regeneration is difficult in human COPD. Maturation, aging, and senescence in COPD lung cells, including endogenous stem cells, may affect the regenerative capacity following pharmacological therapy. The lung is a complex organ composed of more than 40 different cell types; therefore, detailed analyses, such as epigenetic modification analysis, in each specific cell type have not been performed in lungs with COPD. Recently, a method for the direct isolation of individual cell types from human lung has been developed, and fingerprints of each cell type in COPD lungs can be analyzed. Research using this technique combined with the recently discovered lung endogenous stem-progenitor populations will give a better understanding about the fate of COPD lung cells and provide a future for cell-based therapy to treat this intractable disease. © AlphaMed Press. Source

To gain insight into the relationship between the spin correlation (SC) and torque correlation (TC) models for the Gilbert damping constant, α, we first make a simple consideration on the physical aspect of these models and calculate α for the Fe50Co50 disordered alloy by the two models using the first principles technique. Electron scattering is introduced through the random arrangement of atoms and is treated with coherent potential approximation. The results indicate that in the TC model, vertex correction (VC) does not have significant contribution and the results are insensitive to the infinitesimal positive value, δ, which is used in Green's function. In the SC model, on the other hand, the VC is indispensable and the obtained values of α are found to be considerably sensitive to δ. We confirm that the value of α in the SC model approaches the value obtained in the TC model in the limit δ→+0. © 2015 AIP Publishing LLC. Source

Tsukiura T.,Duke University | Tsukiura T.,Tohoku University | Cabeza R.,Duke University
NeuroImage | Year: 2011

Behavioral data have shown that attractive faces are better remembered but the neural mechanisms of this effect are largely unknown. To investigate this issue, female participants were scanned with event-related functional MRI (fMRI) while rating the attractiveness of male faces. Memory for the faces was tested after fMRI scanning and was used to identify successful encoding activity (subsequent memory paradigm). As expected, attractive faces were remembered better than other faces. The study yielded three main fMRI findings. First, activity in the right orbitofrontal cortex increased linearly as a function of attractiveness ratings. Second, activity in the left hippocampus increased as a function of subsequent memory (subsequent misses < low confidence hits < high confidence hits). Third, functional connectivity between these orbitofrontal and hippocampal regions was stronger during the encoding of attractive than neutral or unattractive faces. These results suggest that better memory for attractive faces reflects greater interaction between a region associated with reward, the orbitofrontal cortex, and a region associated with successful memory encoding, the hippocampus. © 2010 Elsevier Inc. Source

Hashimoto J.,Tohoku University
Tohoku Journal of Experimental Medicine | Year: 2014

Recent advances in technology have enabled the noninvasive evaluation of pulsatile hemodynamics in the central aorta; namely, central pressure and flow measurements. The central blood pressure represents the true load imposed on the heart, kidney and brain, and the central blood flow influences the local flow into these vital organs. An elevation of the central blood pressure has a direct, adverse impact on the target organ and, thus, the cardiovascular prognosis in patients with hypertension. A decrease in the central blood flow can cause organ dysfunction and failure. The central pressure and flow dynamics were conventionally regarded as unidirectional from the heart to the periphery. However, current evidence suggests that it should be recognized as a bidirectional interplay between the central and peripheral arteries. Specifically, the pressure pulse wave is not only transmitted forward to the periphery but also reflected backward to the central aorta. The flow pulse wave is also composed of the forward and reverse components. Aortic stiffening and arteriolar remodeling due to hypertension not only augment the central pressure by increasing the wave reflection but also may alter the central bidirectional flow, inducing hemodynamic damage/dysfunction in susceptible organs. Therefore, central hemodynamic monitoring has the potential to provide a diagnostic and therapeutic basis for preventing systemic target organ damage and for offering personalized therapy suitable for the arterial properties in each patient with hypertension. This brief review will summarize hypothetical mechanisms for the association between the central hemodynamics and hypertensive organ damage in the heart, kidney and brain. © 2014 Tohoku University Medical Press. Source

Suzuki M.,Tohoku University
Proceedings of the Japan Academy Series B: Physical and Biological Sciences | Year: 2014

Assisted reproductive technology (ART) such as in vitro fertilization (IVF) and embryo transfer (ET) has been essential in the treatment of infertility. The world's first IVF-ET baby was born in 1978 based on the technique developed by Dr. Robert Edwards and Dr. Patrick Steptoe.1) In Japan, the first IVF-ET birth was reported in 1983 by Prof. Masakuni Suzuki at Tohoku University School of Medicine. IVF-ET is a procedure used to achieve pregnancy that consists of extracting oocytes from an infertile woman, fertilizing them in vitro, and transferring fertilized eggs into the patient's uterine cavity (Fig. 1). Since the first report of successful IVF-ET, numerous techniques related to ART, such as cryopreservation of oocytes and embryos, gamete intrafallopian transfer (GIFT), and microinsemination, have been developed and refined (Table 1). Herein we describe the history of basic research in IVF-ET that led to human applications, how the birth of the first IVF-ET baby was achieved in Japan, the current status of ART in Japan, issues related to ART, and future prospects for ART. © 2014 The Japan Academy. Source

Ri S.,Japan National Institute of Advanced Industrial Science and Technology | Muramatsu T.,Tohoku University
Applied Optics | Year: 2012

Recently, a rapid and accurate single-shot phase measurement technique called the sampling moiré method has been developed for small-displacement distribution measurements. In this study, the theoretical phase error of the sampling moiré method caused by linear intensity interpolation in the case of a mismatch between the sampling pitch and the original grating pitch is analyzed. The periodic phase error is proportional to the square of the spatial angular frequency of the moiré fringe. Moreover, an effective phase compensation methodology is developed to reduce the periodic phase error. Single-shot phase analysis can perform accurately even when the sampling pitch is not matched to the original grating pitch exactly. The primary simulation results demonstrate the effectiveness of the proposed phase compensation methodology. © 2012 Optical Society of America. Source

Greer A.L.,University of Cambridge | Greer A.L.,Tohoku University | Cheng Y.Q.,Oak Ridge National Laboratory | Ma E.,Johns Hopkins University
Materials Science and Engineering R: Reports | Year: 2013

Shear-banding is a ubiquitous plastic-deformation mode in materials. In metallic glasses, shear bands are particularly important as they play the decisive role in controlling plasticity and failure at room temperature. While there have been several reviews on the general mechanical properties of metallic glasses, a pressing need remains for an overview focused exclusively on shear bands, which have received tremendous attention in the past several years. This article attempts to provide a comprehensive and up-to-date review on the rapid progress achieved very recently on this subject. We describe the shear bands from the inside out, and treat key materials-science issues of general interest, including the initiation of shear localization starting from shear transformations, the temperature and velocity reached in the propagating or sliding band, the structural evolution inside the shear-band material, and the parameters that strongly influence shear-banding. Several new discoveries and concepts, such as stick-slip cold shear-banding and strength/plasticity enhancement at sub-micrometer sample sizes, will also be highlighted. The understanding built-up from these accounts will be used to explain the successful control of shear bands achieved so far in the laboratory. The review also identifies a number of key remaining questions to be answered, and presents an outlook for the field. © 2013 Elsevier B.V. All rights reserved. Source

Murota K.,Tokyo University of Information Sciences | Shioura A.,Tohoku University
Mathematical Programming | Year: 2014

Dijkstra's algorithm is a well-known algorithm for the single-source shortest path problem in a directed graph with nonnegative edge length. We discuss Dijkstra's algorithm from the viewpoint of discrete convex analysis, where the concept of discrete convexity called L-convexity plays a central role. We observe first that the dual of the linear programming (LP) formulation of the shortest path problem can be seen as a special case of L-concave function maximization. We then point out that the steepest ascent algorithm for L-concave function maximization, when applied to the LP dual of the shortest path problem and implemented with some auxiliary variables, coincides exactly with Dijkstra's algorithm. © 2013 Springer-Verlag Berlin Heidelberg and Mathematical Optimization Society. Source

Ashino T.,Showa University | Yamamoto M.,Tohoku University | Yoshida T.,Showa University | Numazawa S.,Showa University
Arteriosclerosis, Thrombosis, and Vascular Biology | Year: 2013

OBJECTIVE: Reactive oxygen species are important mediators for platelet-derived growth factor (PDGF) signaling in vascular smooth muscle cells, whereas excess reactive oxygen species-induced oxidative stress contributes to the development and progression of vascular diseases, such as atherosclerosis. Activation of the redox-sensitive transcription factor, nuclear factor erythroid 2-related factor 2 (Nrf2), is pivotal in cellular defense against oxidative stress by transcriptional upregulation of antioxidant proteins. This study aimed to elucidate the role of Nrf2 in PDGF-mediated vascular smooth muscle cell migration and neointimal hyperplasia. APPROACH AND RESULTS: PDGF promoted nuclear translocation of Nrf2, followed by the induction of target genes, including NAD(P)H:quinone oxidoreductase-1, heme oxygenase-1, and thioredoxin-1. Nrf2 depletion by small interfering RNA enhanced PDGF-promoted Rac1 activation and reactive oxygen species production and persistently phosphorylated downstream extracellular signal-regulated kinase-1/2. Nrf2 depletion enhanced vascular smooth muscle cell migration in response to PDGF and wound scratch. In vivo, Nrf2-deficient mice showed enhanced neointimal hyperplasia in a wire injury model. CONCLUSION: These findings suggest that the Nrf2 system is important for PDGF-stimulated vascular smooth muscle cell migration by regulating reactive oxygen species elimination, which may contribute to neointimal hyperplasia after vascular injury. Our findings provide insight into the Nrf2 system as a novel therapeutic target for vascular remodeling and atherosclerosis. © 2013 American Heart Association, Inc. Source

Yamazaki S.,Tohoku University
Nature communications | Year: 2013

Erythropoietin regulates erythropoiesis in a hypoxia-inducible manner. Here we generate inherited super-anaemic mice (ISAM) as a mouse model of adult-onset anaemia caused by erythropoietin deficiency. ISAM express erythropoietin in the liver but lack erythropoietin production in the kidney. Around weaning age, when the major erythropoietin-producing organ switches from the liver to the kidney, ISAM develop anaemia due to erythropoietin deficiency, which is curable by administration of recombinant erythropoietin. In ISAM severe chronic anaemia enhances transgenic green fluorescent protein and Cre expression driven by the complete erythropoietin-gene regulatory regions, which facilitates efficient labelling of renal erythropoietin-producing cells. We show that the majority of cortical and outer medullary fibroblasts have the innate potential to produce erythropoietin, and also reveal a new set of erythropoietin target genes. ISAM are a useful tool for the evaluation of erythropoiesis-stimulating agents and to trace the dynamics of erythropoietin-producing cells. Source

Iki N.,Tohoku University
Supramolecular Chemistry | Year: 2011

Luminescent complexes consisting of lanthanide, heterometal and ligands can provide supramolecular functions such as extended luminescent lifetime, near-infrared emission and sensing, which result from the heterometal assembly and cannot be realised with a lanthanide homonuclear complex. In this article, kinetic and thermodynamic strategies to construct such supramolecular complexes are reviewed. The kinetic strategy owes to the kinetic inertness of the intermediary homonuclear complex, but allows use of a wide variety of di- or multitopic ligands including relatively simple ones. On the other hand, the ligand used in the thermodynamic strategy so far has been designed with covalent joining of the selective binding sites as exemplified by the highly sophisticated triple-helical complexes. With the view of avoiding elaborate synthesis of ligands in the thermodynamic strategy, supramolecular functional complexes consisting of thiacalixarene, AgI and lanthanide are described, suggesting the possibility of a small simple ligand to serve as a building block in the thermodynamically obtained supramolecular complex. © 2011 Taylor & Francis. Source

Sax N.,Tohoku University
Pharmaceutical research | Year: 2013

Liposomes encapsulating perfluoropropane gas, termed acoustic liposomes (ALs), which can serve both for ultrasound (US) imaging and US-mediated gene delivery, have been reported. However, the echogenicity of ALs decreases within minutes in vivo due to gas diffusion and leakage, hindering time-consuming procedures such as contrast-enhanced 3D US imaging and raising the need for improvement of their stability. The stability of ALs preparations incorporating increasing ratios of anionic / unsaturated phospholipids, polyethylene glycol (PEG)ylated phospholipid and cholesterol was investigated by measurement of their reflectivity over time using a high-frequency US imaging system, both in vitro and in vivo. The retention of echogenicity of ALs in vitro is enhanced with increasing molar ratios of PEGylated lipids. Addition of 10 molar percent of an anionic phospholipid resulted in a 31% longer half-life, while cholesterol had the opposite effect. Assessment of the stability of an optimized composition showed a more than 2-fold increase of the detection half-life in mice. Presence of a PEG coating not only serves to provide "stealth" properties in vivo, but also contributes to the retention of the encapsulated gas. The optimized ALs reported here can be used as a contrast agent for lengthier imaging procedures. Source

Yamaya M.,Tohoku University
Pulmonary Medicine | Year: 2012

Infection with respiratory viruses, including rhinoviruses, influenza virus, and respiratory syncytial virus, exacerbates asthma, which is associated with processes such as airway inflammation, airway hyperresponsiveness, and mucus hypersecretion. In patients with viral infections and with infection-induced asthma exacerbation, inflammatory mediators and substances, including interleukins (ILs), leukotrienes and histamine, have been identified in the airway secretions, serum, plasma, and urine. Viral infections induce an accumulation of inflammatory cells in the airway mucosa and submucosa, including neutrophils, lymphocytes and eosinophils. Viral infections also enhance the production of inflammatory mediators and substances in airway epithelial cells, mast cells, and other inflammatory cells, such as IL-1, IL-6, IL-8, GM-CSF, RANTES, histamine, and intercellular adhesion molecule-1. Viral infections affect the barrier function of the airway epithelial cells and vascular endothelial cells. Recent reports have demonstrated augmented viral production mediated by an impaired interferon response in the airway epithelial cells of asthma patients. Several drugs used for the treatment of bronchial asthma reduce viral and pro-inflammatory cytokine release from airway epithelial cells infected with viruses. Here, I review the literature on the pathogenesis of the viral infection-induced exacerbation of asthma and on the modulation of viral infection-induced airway inflammation. © 2012 Mutsuo Yamaya. Source

Inoue S.,Tohoku University | Inoue S.,University College London | Saitoh T.R.,Tokyo Institute of Technology
Monthly Notices of the Royal Astronomical Society | Year: 2012

Bulges in spiral galaxies have been supposed to be classified into classical bulges or pseudo-bulges. Classical bulges are thought to form by galactic merger with bursty star formation, whereas pseudo-bulges are suggested to form by secular evolution due to spiral arms and a barred structure funnelling gas into the galactic centre. Noguchi suggested another bulge formation scenario, 'clump-origin bulge'. He demonstrated using a numerical simulation that a galactic disc suffers dynamical instability to form clumpy structures in the early stage of disc formation since the premature disc is expected to be highly gas rich, then the clumps are sucked into the galactic centre by dynamical friction and merge into a single bulge at the centre. This bulge formation scenario, which is expected to happen only at the high redshift, is different from the galactic merger and the secular evolution. Therefore, clump-origin bulges may have their own unique properties. We perform a high-resolution N-body/smoothed particle hydrodynamics simulation for the formation of the clump-origin bulge in an isolated galaxy model and study dynamical and chemical properties of the clump-origin bulge. We find that the clump-origin bulge resembles pseudo-bulges in dynamical properties, a nearly exponential surface density profile, a barred boxy shape and a significant rotation. We also find that this bulge consists of old and metal-rich stars, displaying resemblance to classical bulges. These natures, old metal-rich population but pseudo-bulge-like structures, mean that the clump-origin bulge cannot be simply classified into classical bulges or pseudo-bulges. From these results, we discuss similarities of the clump-origin bulge to the Milky Way bulge. Combined with a result of Elmegreen et al., this pseudo-bulge-like clump-origin bulge could be inferred to form in clump clusters with a relatively low surface density. © 2012 The Authors Monthly Notices of the Royal Astronomical Society © 2012 RAS. Source

Kurosawa S.,Tohoku University
Current Opinion in Anaesthesiology | Year: 2012

Purpose of review: Along with the increasing population of elderly people in developed countries, anesthesiologists have increasing opportunities to anesthetize cancer patients in their routine work. However, no guideline of anesthesia procedures for cancer patients is available even though guidelines of operative procedures have been formulated for different types of cancer. This review provides Recent findings related to the optimal choice of anesthetics and adequate anesthesia management for cancer patients. Recent findings: The intrinsic weapon fighting cancer cells is competent immune cells, particularly CD4 + T helper 1-type cells, CD8 + cytotoxic T cells, and natural killer cells. However, surgical inflammation, some anesthetics, and inadvertent anesthesia management suppress these effector cells and induce suppressive immune cells, which render cancer patients susceptible to tumor recurrence and metastasis after surgery. Summary: Accumulated basic and clinical data suggest that total intravenous anesthesia with propofol, cyclooxygenase antagonists, and regional anesthesia can decrease negative consequences associated with perioperative immunosuppression. Volatile anesthesia, systemic morphine administration, unnecessary blood transfusions, intraoperative hypoxia, hypotension, hypothermia, and hyperglycemia should be avoided. © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins. Source

Hagiya M.,University of Tokyo | Konagaya A.,Tokyo Institute of Technology | Kobayashi S.,University of Electro - Communications | Saito H.,Kyoto University | Murata S.,Tohoku University
Accounts of Chemical Research | Year: 2014

ConspectusWhat we can call a molecular robot is a set of molecular devices such as sensors, logic gates, and actuators integrated into a consistent system. The molecular robot is supposed to react autonomously to its environment by receiving molecular signals and making decisions by molecular computation. Building such a system has long been a dream of scientists; however, despite extensive efforts, systems having all three functions (sensing, computation, and actuation) have not been realized yet.This Account introduces an ongoing research project that focuses on the development of molecular robotics funded by MEXT (Ministry of Education, Culture, Sports, Science and Technology, Japan). This 5 year project started in July 2012 and is titled "Development of Molecular Robots Equipped with Sensors and Intelligence".The major issues in the field of molecular robotics all correspond to a feedback (i.e., plan-do-see) cycle of a robotic system. More specifically, these issues are (1) developing molecular sensors capable of handling a wide array of signals, (2) developing amplification methods of signals to drive molecular computing devices, (3) accelerating molecular computing, (4) developing actuators that are controllable by molecular computers, and (5) providing bodies of molecular robots encapsulating the above molecular devices, which implement the conformational changes and locomotion of the robots.In this Account, the latest contributions to the project are reported. There are four research teams in the project that specialize on sensing, intelligence, amoeba-like actuation, and slime-like actuation, respectively. The molecular sensor team is focusing on the development of molecular sensors that can handle a variety of signals. This team is also investigating methods to amplify signals from the molecular sensors. The molecular intelligence team is developing molecular computers and is currently focusing on a new photochemical technology for accelerating DNA-based computations. They also introduce novel computational models behind various kinds of molecular computers necessary for designing such computers. The amoeba robot team aims at constructing amoeba-like robots. The team is trying to incorporate motor proteins, including kinesin and microtubules (MTs), for use as actuators implemented in a liposomal compartment as a robot body. They are also developing a methodology to link DNA-based computation and molecular motor control. The slime robot team focuses on the development of slime-like robots. The team is evaluating various gels, including DNA gel and BZ gel, for use as actuators, as well as the body material to disperse various molecular devices in it. They also try to control the gel actuators by DNA signals coming from molecular computers. © 2014 American Chemical Society. Source

Gynecology in the office setting is developing worldwide. Clinical guidelines for office gynecology were first published by the Japan Society of Obstetrics and Gynecology and the Japan Association of Obstetricians and Gynecologists in 2011. These guidelines include a total of 72 clinical questions covering four areas (Infectious disease, Malignancies and benign tumors, Endocrinology and infertility, and Healthcare for women). These clinical questions were followed by several answers, backgrounds, explanations and references covering common problems and questions encountered in office gynecology. Each answer with a recommendation level of A, B or C has been prepared based principally on evidence or consensus among Japanese gynecologists.These guidelines would promote a better understanding of the current standard care practices for gynecologic outpatients in Japan. © 2012 The Authors; Journal of Obstetrics and Gynaecology Research © 2012 Japan Society of Obstetrics and Gynecology. Source

Shigeta M.,Tohoku University
Plasma Sources Science and Technology | Year: 2012

A time-dependent 3D numerical simulation using a large eddy simulation approach is conducted to meet the first challenge in revealing the coherent vortex structure and dynamic behaviours of the thermofluid field in a radio-frequency inductively coupled thermal plasma torch. The high-temperature plasma region exhibits unsteady behaviour near the coil. At the same time, the high- and low-temperature flows form undulating interfaces. The flow field has a complicated 3D structure with a recirculating zone due to Lorentz forces. Because of the recirculating flow, the injected cold gas tends to avoid the high-temperature plasma region. The largest vortex structure, at approximately 10000K, remains in the plasma region, whereas small cold eddies are generated near the top wall of the torch and transported downstream, avoiding the plasma region. In the intermediate-temperature regions around the plasma, relatively large vortices are repeatedly born and dissolve, connecting with and separating from each other. Most of them have non-uniform temperatures because they are easily generated in the interfacial regions with temperature gradients around a thermal plasma flow. The time scale of the transport of cold eddies is much smaller than that of the dynamic motion of the high-temperature plasma region. © 2012 IOP Publishing Ltd. Source

Ohnishi N.,Tohoku University
High Energy Density Physics | Year: 2012

A radiation hydrodynamics code has been developed for more accurate prediction of laser-produced low-density ablation plasmas with appropriately describing anisotropic radiation field by using Monte-Carlo technique for variable Eddington tensor with reasonable computational loads. The Eddington tensor estimated by thousand of sample particles per single fluid step can reproduce the anisotropic radiation field in the low-density region and will not result in large computational consumption. Prediction of the emitted light from ablation plasma can be corrected by the proposed method. Ablation structure sustained by a compact radiation source, which is sometimes found in experiments of collisionless shock relevant to laboratory astrophysics, may also be changed by anisotropic transfer computation in optically thin region. © 2012 Elsevier B.V. Source

Sugiyama N.S.,Tohoku University
Journal of Cosmology and Astroparticle Physics | Year: 2012

The consistency relation between non-linear parameters f NL and τ NL characterizing Non-Gaussianity generated in the super horizon scale have been emerged as a useful tool to rule out a large class of inflationary models all at once. In our previous work, we extended the Suyama-Yamaguchi inequality up to 1-loop corrections. In this paper, we further extend the inequality up to all loop corrections, and found that it takes the same expression with the original Suyama-Yamaguchi inequality, τ NL ((6/5)f NL) 2, where the equality is not satisfied in the case of single field models any more. © 2012 IOP Publishing Ltd and Sissa Medialab srl. Source

Ozawa T.,Tohoku University
Molecular Medicine Reports | Year: 2010

Ryanodine-sensitive Ca2+ release channels (ryanodine receptors, RyRs) play a crucial role in the mobilization of Ca2+ from the sarcoplasmic reticulum (SR) during the excitation-contraction coupling of muscle cells. In skeletal muscle, depolarization of transverse tubules activates the RyR, whereas in cardiac muscle, a Ca2+ influx through an L-type Ca2+ channel activates the RyR. The RyR is also activated by caffeine, a low concentration (<10 μM) of ryanodine or cyclic AD P-ribose. RyR activity is inhibited by Mg2+, ruthenium red, or higher concentrations (≥100 μM) of ryanodine. The activity of RyR channels is modulated by phosphorylation and by associated proteins, including calmodulin (CaM), calsequestrin (CSQ) and FK506-binding proteins (FKBPs). In muscle cells, apoCaM (Ca2+-free CaM) activates the RyR channel, and Ca2+ CaM (Ca2+-bound CaM) inhibits the channel. CSQ can bind approximately 40 moles of Ca2+/mole of CSQ in the SR lumen of muscle cells, and interacts functionally with RyR protein. When the RyR is stimulated, Ca2+ released from the lumen is dissociated from the CSQ-Ca 2+ complex. A 12-kDa or 12.6-kDa FK506-binding protein (FKBP12 or FKBP12.6, respectively) is associated with RyR protein. When FKBP12 or FKBP12.6 is dissociated from the FKBP-RyR complex, the RyR is modulated (activated). Phosphorylation of the RyR by cAMP-dependent protein kinase (PKA) and Ca 2+/calmodulin-dependent protein kinase II II modulates the channel. PKA phosphorylation of the RyR on the skeletal and cardiac muscle SR dissociates FKBP12 or FKBP12.6 from the RyR complex. This review deals with the modulation mechanisms of RyR proteins by associated proteins and phosphorylation. Source

Matsue T.,Tohoku University
Analytical Sciences | Year: 2013

This article presents an overview of the recent progress made by our group in the development of bioelectrochemical imaging devices and systems with micro/nanoelectrodes. The topics include bioimaging of enzymes and live cells by scanning electrochemical microscopy (SECM), high-resolution bioimaging by SECM equipped with a nanoprobe, comprehensive measurements and bioimaging with local-redox cycling-based electrochemical (LRC-EC) devices, and rapid and sensitive bioimaging with BioLSI. © The Japan Society for Analytical Chemistry. Source

The dynamics of quantum systems strongly depends on the local structure of the Hamiltonian. For short-range interacting systems, the well-known Lieb-Robinson bound defines the effective light cone with an exponentially small error with respect to the spatial distance, whereas we can obtain only polynomially small errors for distance in long-range interacting systems. In this paper, we derive a qualitatively new bound for quantum dynamics by considering how many spins can correlate with each other after time evolution. Our bound characterizes the number of spins which support the many-body entanglement with exponentially small errors and is valid for a large class of Hamiltonians including long-range interacting systems. To demonstrate the advantage of our approach in quantum many-body systems, we apply our bound to prove several fundamental properties which have not been derived from the Lieb-Robinson bound. © 2016 IOP Publishing Ltd and Deutsche Physikalische Gesellschaft. Source

Tsai A.-P.,Tohoku University | Tsai A.-P.,Japan National Institute of Materials Science
Chemical Society Reviews | Year: 2013

The geometrical concept and structural framework of quasicrystals (QCs) were established shortly after the discovery of QCs. Specifically, the static and dynamic properties of the atoms and the electronic structures of quasiperiodic lattices were theoretically developed. Experimental studies lagged behind theoretical progress due to the lack of suitable samples. This situation changed with the discovery of several highly ordered stable QCs. Studies of these new QCs have provided new insights into the structure and properties of QCs. This article chronologically reviews the discoveries of various stable icosahedral QCs and subsequent studies that determined their structures, properties, and stabilization mechanisms. © 2013 The Royal Society of Chemistry. Source

Watanabe N.,Tohoku University
Methods in Enzymology | Year: 2012

Cells must rapidly remodel the actin filament network to achieve various cellular functions. Actin filament turnover is a dynamic process that plays crucial roles in cell adhesion, locomotion, cytokinesis, endocytosis, phagocytosis, tissue remodeling, etc., and is regulated by cell signaling cascades. Success in elucidating dynamic biological processes such as actin-based motility relies on the means enabling real time monitoring of the process. The invention of live-cell fluorescence single-molecule imaging has opened a window for direct viewing of various actin remodeling processes. In general, assembly and dissociation of actin and its regulators turned out to occur at the faster rates than previously estimated by biochemical and structural analyses. Cells undergo such fast continuous exchange of the components perhaps not only to drive actin remodeling but also to facilitate rapid response in many other cell mechanics and signaling cascades. This chapter describes how epifluorescence single-molecule imaging which visualizes deeper area than the TIRF microscopy is achieved in XTC cells, the currently best platform for this approach. © 2012 Elsevier Inc. Source

The great amounts of finds comprising lithic artefacts, faunal remains, figurative arts and architectural remains from Gönnersdorf suggest this site was repeatedly occupied as a base camp over a period of many years. This study examines activities performed at Gönnersdorf K-II based on traceological analysis. The intensive, diverse usewear traces observed on the lithic assemblage indicate that a series of activities including hunting, butchery, processing of carcass remains, and stone-working was conducted at Gönnersdorf. This result contrasts with scarcity of usewear traces on flint artefacts at Eyserheide and also with the evidence of the specific function as a hunting camp at Bois Laiterie cave, which are both reconstructed on the basis of traceological investigations. Thus, this study shows completely different aspects of Magdalenian sites represented by traces on the lithic assemblages. The functional variability reflects a glimpse of the complementary site functions within the Magdalenian settlement-subsistence system in north-western Europe. © 2012 Elsevier Ltd and INQUA. Source

Sugawara D.,Tohoku University | Goto K.,Chiba Institute of Technology
Sedimentary Geology | Year: 2012

This paper examines the results of a numerical modeling of the 2011 Tohoku-oki earthquake tsunami to investigate its offshore propagation and inundation along a shore-normal transect located in the center of the Sendai Plain. The inundation distance, flow depth, and flow speed were compared with the available data measured during a post-tsunami field survey and estimated from the video records. The calculated inundation distance reached 4.5-5.5. km from the coastline, which is comparable to the actual inundation distance. The variation of tsunami heights from 2.4-6. m and flow speeds from 3.4-6.2. m/s along the transect is generally consistent with the measured heights and estimated speeds. The waveform on the beach showed that the wave train was composed of a high (10-11. m) first wave followed by low (~. 4. m) waves. Considering the waveform and the topographic change, the erosion of the beach and the sedimentation inland are explained mainly by the first wave. In addition, the calculated flow speed and friction velocities in the offshore may account for the formation of the possible tsunami deposits, which were reported recently by a sea-bottom survey. The modeling results are generally consistent with the available data and are considered to be useful for understanding the inundation pattern and sedimentation process of the Tohoku-oki tsunami on the Sendai Plain. © 2012 Elsevier B.V. Source

Kazama M.,Tohoku University | Noda T.,Nagoya University
Soils and Foundations | Year: 2012

The 2011 off the Pacific Coast of Tohoku Earthquake, which occurred on March 11, 2011, caused enormous damage, particularly to the strip of land along the Pacific Ocean from the Tohoku Region to the Kanto Region, due to seismic motion and the tsunami it triggered. This report presents an outline of the earthquake and summarizes the associated seismic damage to social infrastructure facilities. © 2012 The Japanese Geotechnical Society. Source

Awaji S.,Tohoku University
Superconductor Science and Technology | Year: 2013

In order to understand the effects of strain on the superconducting properties in composite Nb3Sn wires and cables, the three-dimensional (3D) strain is very important. Quantum beams such as neutron and synchrotron radiation enable us to quantify the detailed internal strain in any direction nondestructively. Therefore, quantum beams are recognized as a powerful tool to evaluate the 3D strain inside composite materials. The internal strain states of Nb3Sn strands in thick conduits such as cable-in-conduit conductors can also be detected because of the large penetration depth of neutrons. Because of advances in neutron and synchrotron radiation facilities, recent studies have examined the internal strains in composite superconducting wire and cable conductors. This paper reviews recent studies on 3D strains and their effects on the superconducting properties of Nb3Sn wires and cable conductors, along with some experimental data. Other applications of quantum beams for superconducting wires are also introduced briefly. © 2013 IOP Publishing Ltd. Source

Feltzing S.,Lund Observatory | Chiba M.,Tohoku University
New Astronomy Reviews | Year: 2013

We present a review of elemental abundances in the Milky Way stellar disk, bulge, and halo with a focus on data derived from high-resolution stellar spectra. These data are fundamental in disentangling the formation history and subsequent evolution of the Milky Way. Information from such data is still limited and confined to narrowly defined stellar samples. The astrometric Gaia satellite will soon be launched by the European Space Agency. Its final data set will revolutionize information on the motions of a billion stars in the Milky Way. This will be complemented by several ground-based observational campaigns, in particular spectroscopic follow-up to study elemental abundances in the stars in detail. Our review shows the very rich and intriguing picture built from rather small and local samples. The Gaia data deserve to be complemented by data of the same high quality that have been collected for the solar neighborhood. © 2013 Elsevier B.V. Source

Egami Y.,Kagawa University | Fukuda M.,Tohoku University | Araki N.,Kagawa University
Journal of Cell Science | Year: 2011

Phagosome formation and subsequent maturation are complex sequences of events that involve actin cytoskeleton remodeling and membrane trafficking. Here, we demonstrate that the Ras-related protein Rab35 is involved in the early stage of FcγR-mediated phagocytosis in macrophages. Live-cell image analysis revealed that Rab35 was markedly concentrated at the membrane where IgGopsonized erythrocytes (IgG-Es) are bound. Rab35 silencing by RNA interference (RNAi) or the expression of GDP- or GTP-locked Rab35 mutant drastically reduced the rate of phagocytosis of IgG-Es. Actin-mediated pseudopod extension to form phagocytic cups was disturbed by the Rab35 silencing or the expression of GDP-Rab35, although initial actin assembly at the IgG-E binding sites was not inhibited. Furthermore, GTP-Rab35-dependent recruitment of ACAP2, an ARF6 GTPase-activating protein, was shown in the phagocytic cup formation. Concomitantly, overexpression of ACAP2 along with GTP-locked Rab35 showed a synergistic inhibitory effect on phagocytosis. It is likely that Rab35 regulates actin-dependent phagosome formation by recruiting ACAP2, which might control actin remodeling and membrane traffic through ARF6. © 2011. Source

Polymer micro-and nano-particles have attracted much attention because of their promise for a variety of applications. This focus review introduces an emerging method for producing nanostructured polymer particles, called self-organized precipitation (SORP), and gives an overview of controlling the internal structure of polymer particles by using various polymer blends and block-copolymer systems. The possible applications and future prospects of this technology are also discussed. © 2013 The Society of Polymer Science, Japan (SPSJ) All rights reserved. Source

Suryanarayana C.,University of Central Florida | Inoue A.,Tohoku University
International Materials Reviews | Year: 2013

The current status of research and development in Fe-based bulk metallic glasses (BMGs) is reviewed. Bulk metallic glasses are relatively new materials possessing a glassy structure and large section thickness. These materials have an exciting combination of properties such as high mechanical strength, good thermal stability, large supercooled liquid region and potential for easy forming. Ever since the first synthesis of an Fe-based BMG in an Fe-Al-Ga-P-C-B system in 1995, there has been intense activity on the synthesis and characterisation of Fe-based BMGs. These BMGs exhibit some unique characteristics which have not been obtained in conventional Fe-based crystalline alloys. This uniqueness has led to practical uses of these bulk glassy alloys as soft magnetic and structural materials. This review presents the recent results on the glassforming ability, structure, thermal stability, mechanical properties, corrosion behaviour, soft magnetic properties and applications of Fe-based bulk glassy alloys developed during the last 15 years. This review also highlights the advanced analysis of their properties which has contributed significantly to the progress in understanding and developing of the Fe-based BMGs. The future prospects of Fe-based BMGs have also been presented. © 2013 Institute of Materials, Minerals and Mining and ASM International. Source

Higashitani A.,Tohoku University
Frontiers in Plant Science | Year: 2013

Plant reproductive development is more sensitive than vegetative growth to many environmental stresses. High temperature (HT) injury is becoming an increasingly serious problem due to recent global warming. In wheat, barley, and other crops, the early phase of anther development is most susceptible to HT. I and my colleagues recently demonstrated that HT causes cell proliferation arrest and represses auxin signaling in a tissue-specific manner in the anther cells of barley and Arabidopsis. HT also caused comprehensive alterations in transcription. The application of auxin at the same time blocked the transcriptional alterations, led to the production of normal pollen grains, and restored the normal seed setting rate under increasing temperatures. Although synthetic auxins have been used widely as potent and selective herbicides, these recent results indicate that auxin is useful for the promotion of fertility and maintenance of crop yields under the threat of global warming. © 2013 Higashitani. Source

This paper explores public attitudes towards science and nature in twelve countries using data from the International Social Survey Programme environment modules of 1993, 2000, and 2010. Analysis of attitude items indicates technocentric and pessimistic dimensions broadly related to the Dominant Social Paradigm and New Environmental Paradigm. A bi-axial dimension scale is utilized to classify respondents among four environmental knowledge orientations. Discernible and significant patterns are found among countries and their populations. Relationships with other substantial variables in the surveys are discussed and findings show that the majority of industrialized countries are clustered in the rational ecologist categorization with respondents possessing stronger ecological consciousness and optimism towards the role of modern institutions, science, and technology in solving environmental problems. © The Author(s) 2013 Source

Pichierri F.,Tohoku University
Chemical Physics Letters | Year: 2013

Using both ab initio and density functional theory (DFT) calculations in combination with basis sets of triple- and quadruple-ξ quality we investigate the molecular and electronic structure of the half-sandwich η5-(Cp*)C+ cation. The results indicate that the lowest-energy rotamer is a C5-symmetric ground state singlet while the triplet state is Cs-symmetric and ∼68 kcal/mol higher in energy. A topological analysis of the theoretical electron density based on the quantum theory of atoms in molecules (QTAIM) indicates that the η5-type bonding between the apical carbon atom and Cp * comprises five bond paths each bearing a bond critical point of type (3,-1). © 2013 Elsevier B.V. All rights reserved. Source

Wakamatsu Y.,Tohoku University
Development Growth and Differentiation | Year: 2011

Cranial sense organs and a subset of cranial sensory neurons are generated from placodes, thickenings of the ectoderm. Pax3 has been known as a marker for ophthalmic trigeminal placode specification, and also an important regulator of trigeminal placode neuron differentiation. In this study, I show that Pax6 is initially expressed in the preplacodal region at the level of ophthalmic trigeminal placode, and that this expression gradually regresses in a medial-to-lateral direction as Pax3 expression expands in the same direction. Misexpression studies revealed that Pax6 represses Pax3 expression indirectly as a transcriptional activator in a cell-autonomous manner. Pax3-misexpression represses Pax6 expression in an indirect fashion, suggesting that unknown factor(s) downstream of Pax3 may repress Pax6 expression, and thereby allow an expansion of Pax3-positive ophthalmic trigeminal placode region. These results indicate that the mutual repression between Pax3 and Pax6 has important roles in the specification and the positioning of the ophthalmic trigeminal placode. © 2011 The Author. Development, Growth & Differentiation © 2011 Japanese Society of Developmental Biologists. Source

Kubota K.,Tohoku University
Microbes and Environments | Year: 2013

Fluorescence in situ hybridization (FISH) has become a standard technique in environmental microbiology. More than 20 years have passed since this technique was first described, and it is currently used for the detection of ribosomal RNA, messenger RNA, and functional genes encoded on chromosomes. This review focuses on the advancement and applications of FISH combined with catalyzed reporter deposition (CARD, also known as tyramide signal amplification or TSA), in the detection of environmental microorganisms. Significant methodological improvements have been made in CARD-FISH technology, including its combination with other techniques and instruments. Source

Fujihara K.,Tohoku University
Journal of the Neurological Sciences | Year: 2011

Neuromyelitis optica (NMO) is characterized by severe optic neuritis and longitudinally extended, transverse myelitis. There have been long controversial whether NMO is a variant of multiple sclerosis (MS) or a different disease. However, since the discovery of an NMO-specific autoantibody to aquaporin 4 (AQP4), a dominant water channel in the central nervous system densely expressed on foot processes of astrocytes, the clinical distinction between NMO and MS has become clear, and now AQP4 antibody status is critically important for neurologists in deciding on treatment strategy. Moreover, pathological studies demonstrated an extensive loss of immunoreactivities to AQP4 and glial fibrillary acidic protein (GFAP) with relative preservation of the staining of myelin basic protein in acute NMO lesions, which is not seen in MS. In fact, the GFAP levels in the cerebrospinal fluid during acute exacerbation of NMO are remarkably elevated, while the values in MS are not different from those in controls. In addition, recent experimental studies conducted in vitro and in vivo have shown that AQP4 antibody is pathogenic. These findings strongly suggest that AQP4 antibody has diagnostic, therapeutic and pathogenetic implications, and that severe astrocytic damage mediated by AQP4 antibody distinguishes NMO from MS. © 2011 Elsevier B.V. All rights reserved. Source

Goto A.,Tohoku University | Johnson J.B.,New Mexico Institute of Mining and Technology
Geophysical Research Letters | Year: 2011

Monotonic infrasound with stable peaked frequency of 0.77 Hz was recorded at Volcan Villarrica in January 2010. Similar monotonic infrasound had been previously reported at Villarrica (e.g., Ripepe et al. [2010]). Using joint infrasound and visual observations from a suspended camera we demonstrate that the likely source of infrasound is Helmholtz resonance produced from a cavity with volume 105 m3 that separates the active convecting lava lake from an overhanging spatter roof. Spatter roof dimension (65 m diameter) and vent diameter (10 m) in the roof are constrained from video observations. Assuming a cylindrical cavity we infer a cavity height of 31 m that is corroborated by video records of spatter drips. The drips take as long as 2.2 s to fall from the roof into the lake, corresponding to a height of more than 24 m, which is in good agreement with the observed resonance frequency. © 2011 by the American Geophysical Union. Source

Nemura H.,Tohoku University
Few-Body Systems | Year: 2011

Recent studies of nuclear forces based on lattice QCD are presented. Not only the central potential but also the tensor potential is deduced from the Nambu-Bethe-Salpeter wave function measured with lattice QCD. This method is applied to various kinds of nuclear potentials, such as VNN, VΛN, VpΞ0,VΛΛ-NΞ-ΣΣ (coupled-channel potential), and V{27,8s,1,10,10̄,8a} (flavor representation potential). The energy dependence and the angular momentum dependence of the quenched VNN is studied. A challenge for three-nucleon force from lattice QCD is also presented. © 2011 Springer-Verlag. Source

Mori T.,University of Tokyo | Kuwahara T.,University of Tokyo | Kuwahara T.,Tohoku University | Saito K.,Keio University
Physical Review Letters | Year: 2016

We discuss the universal nature of relaxation in isolated many-body quantum systems subjected to global and strong periodic driving. Our rigorous Floquet analysis shows that the energy of the system remains almost constant up to an exponentially long time in frequency for arbitrary initial states and that an effective Hamiltonian obtained by a truncation of the Floquet-Magnus expansion is a quasiconserved quantity in a long time scale. These two general properties lead to an intriguing classification on the initial stage of relaxation, one of which is similar to the prethermalization phenomenon in nearly integrable systems. © 2016 American Physical Society. Source

Anekawa T.,Tohoku University
Nature Nanotechnology | Year: 2016

Spin–orbit torque, a torque brought about by in-plane current via the spin–orbit interactions in heavy-metal/ferromagnet nanostructures, provides a new pathway to switch the magnetization direction. Although there are many recent studies, they all build on one of two structures that have the easy axis of a nanomagnet lying orthogonal to the current, that is, along the z or y axes. Here, we present a new structure with the third geometry, that is, with the easy axis collinear with the current (along the x axis). We fabricate a three-terminal device with a Ta/CoFeB/MgO-based stack and demonstrate the switching operation driven by the spin–orbit torque due to Ta with a negative spin Hall angle. Comparisons with different geometries highlight the previously unknown mechanisms of spin–orbit torque switching. Our work offers a new avenue for exploring the physics of spin–orbit torque switching and its application to spintronics devices. © 2016 Nature Publishing Group Source

Yasunaka S.,University of Tokyo | Hanawa K.,Tohoku University
International Journal of Climatology | Year: 2011

Seven historical sea surface temperature (SST) datasets are compared with each other: the Hadley Center sea ice and SST dataset (HadISST), version 1; the centennial in situ observation-based estimate of SSTs (COBE); the extended reconstruction of global SST (ERSST), version 3; the optimal smoothing analysis by the Lamont-Doherty Earth Observatory (LDEO); the monthly summaries of the International Comprehensive Ocean-Atmosphere Data Set Release 2.1 (ICOADS); the second Hadley Center SST (HadSST); and SSTs by the authors at Tohoku University (TOHOKU). Differences in 30-year climatologies and standard deviations of anomalies from the climatologies exist, especially in observation-sparse areas and periods. Correlation among the datasets mainly depends on the number of observational data. Global means from all datasets are consistent with each other except for those from ICOADS. Signals of the El Niño/Southern Oscillation (ENSO) correlate highly with each other after 1880, although the durations and intensities of each event are different. Temporal variations of the Pacific Decadal Oscillation (PDO) correspond well after 1950, become gradually worse backward in time and are scattered before 1880. These differences are ascribed to the use of different interpolation methods for missing grids, treatments of satellite-derived data, instrumental bias correction methods and other factors. © 2011 Royal Meteorological Society. Source

Glycine encephalopathy (GE), also known as non-ketotic hyperglycinemia, is a life-threatening metabolic disease caused by inherited deficiency of the glycine cleavage system (GCS). GE is characterized by accumulation of a large amount of glycine in serum and cerebrospinal fluids. In typical cases with GE, coma, profound hypotonia, and intractable seizures develop within several days of life. Patients with atypical symptoms may have delayed or missed diagnosis because of non-specific symptoms. It is sometimes problematic to confirm the diagnosis of GE since it requires either invasive liver biopsy for measurement of GCS activity or exhaustive mutational screening of three GCS genes, GLDC, AMT, and GCSH. We herein describe two novel laboratory tests for diagnosis of GE, [1- 13C]glycine breath test and the multiplex ligation-dependent probe amplification (MLPA) for detection of large deletions in GLDC. The [1- 13C]glycine breath test has been developed for noninvasive enzymatic diagnosis of GE. Because the GCS generates CO 2 by degradation of glycine, the GCS activity could be evaluated in vivo by measurement of exhaled 13CO 2 after administration of a stable isotope, [1- 13C]glycine. The MLPA has been developed for improvement in mutation detection rate in GE: Deletions involving multiple GDLC exons are prevalent among GE patients, but cannot be detected by the exon-sequencing analysis. Two novel diagnosis methods would facilitate diagnosis of hyperglycinemic patients as having GE. © 2011 The Japanese Society of Child Neurology. Source

Pichierri F.,Tohoku University
Dalton Transactions | Year: 2013

Using density functional theory (DFT) calculations and the available crystallographic data we have investigated the binding of hydrated Cs + ions to the pumpkin-shaped cucurbituril macrocycles, CB[n] with n = 5-7. The calculations indicate that besides the interactions between caesium ions and the carbonyl-laced portals, also the hydrogen bonds established between the coordinated water molecules and the macrocycle do contribute to the overall binding affinity. Although the other alkali metal ions compete for binding with caesium, the partial dehydration of the caesium aqua ions is likely favoured by the relatively small interaction energy associated with the water-Cs + bond. The inclusion inside the macrocycle's cavity of either one water molecule or one chloride anion enhances the binding of Cs+ due to the additional ion-dipole or ion-ion interactions, respectively, established within the complexes. An advantage in using cucurbituril macrocycles for the sequestration of caesium ions from an aqueous solution is the possibility of binding two hydrated metal ions by the carbonyl-laced portals thereby forming 1:2 complexes. © 2013 This journal is The Royal Society of Chemistry. Source

Litasov K.D.,Tohoku University
Russian Geology and Geophysics | Year: 2011

Experimental data on phase transformations and melting in peridotite and eclogite systems with a C-O-H fluid at 6-30 GPa have been analyzed with special attention to the influence of redox conditions. It has been found that melting in systems with H2O depends heavily on its total content and considerably on its solubility in nominally anhydrous rock-forming minerals. Partial melting occurs when the total H2O content of the system exceeds the H2O storage capacity in the rock under given physicochemical conditions. Melting in CO2-containing systems is determined by carbonate stability and the chemical composition of the system, mainly its Na2O and K2O contents, and, to a smaller extent, the content of CO2 itself. Studies of peridotite and eclogite systems containing H2O, CO2, H2O + CO2, and a reduced C-O-H fluid show that most solidi flatten out at pressures above 6-8 GPa when intersecting the geotherms of subduction and average mantle. Mantle melting at constant pressure in the presence of a C-O-H fluid depends not only on temperature but also on redox conditions. The oxidation of the system causes redox melting. The stability boundary of a Fe-Ni alloy (it may coincide with the lithosphere-asthenosphere boundary under cratons, 200-250 km) and the 410-km discontinuity are paramount to redox and decarbonation-dehydration melting. Also, the paper provides evidence that subducted carbonates play the leading role in the "big" mantle wedge model for stagnant slabs. Volatile-containing eclogite systems melt at lower temperatures than peridotite ones (the difference is up to 100-200 °C). This suggests that eclogites are of global importance in mantle melting, which agrees with modern geochemical models. © 2011. Source

Identification of similar seismic events is important for precise estimation of source locations and for evaluation of subsurface structure. Phase-only correlation is well known as a real-time image-matching method for fingerprint identification. I applied the phase-only correlation in a geophysical context to identify similar waveforms among microseismic events. The waveforms were first transformed into time-varying spectral representations to express frequency content in the time-frequency domain. The phase-only correlation function is calculated between two time-varying spectral representations and similarity is evaluated using the peak value of the phase-only correlation function. This method was applied to arbitrarily selected waveforms from aftershocks of an earthquake in Japan to assess its ability to identify similar waveforms perturbed by white noise. The detection of similarity of the proposed algorithm was compared to the similarity as detected by a 2D crosscorrelation function of the time-varying spectral representation and a 1D crosscorrelation of the raw waveform. This showed that the phase-only correlation function exhibits a sharp peak that quantifies similarity and dissimilarity over a wide range of signal-to-noise ratio (S/N) and remained unaffected by the length of the time window used to estimate time-varying spectral representations. Phase-only correlation may also have applications in other geophysical analyses and interpretations that are based on waveform and seismic image data. © 2011 Society of Exploration Geophysicists. Source

Gando Y.,Tohoku University
Nuclear and Particle Physics Proceedings | Year: 2016

We report on preliminary results from the second phase of KamLAND-Zen double beta decay search experiment based on 114.8 days with 383 kg of 136Xe. Second phase of KamLAND-Zen was started after the purification to reduce the dominant 110mAg background identified by first phase data. The background was reduced by more than a factor of 10 by purification for liquid scintillator and xenon gas. By combining the first and second phase data and applying the improved event selection, we obtained a preliminary lower limit for the neutrinoless double-beta decay half-life, T1/2 0ν>2.6×1025 yr at 90% C.L. We also present the prospects about current phase of KamLAND-Zen and next phases with upgrades. © 2015 Elsevier B.V.. Source

Kawabata S.,Tohoku University
Nuclear and Particle Physics Proceedings | Year: 2016

A new method to measure the mass of the top quark at the LHC is presented [1]. This method uses lepton energy distribution and ideally does not depend on the velocity distribution of the top quark. We perform a simulation analysis of the top quark mass reconstruction using this method at the leading order, taking account of experimental circumstances. We estimate the sensitivity of the mass determination. The results show that this method is viable in realistic experimental conditions and has a possibility to achieve a good accuracy in determining a theoretically well-defined top quark mass by including higher-order corrections. © 2016 Elsevier B.V. Source

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. Source

Koshino M.,Tohoku University | McCann E.,Lancaster University
Physical Review B - Condensed Matter and Materials Physics | Year: 2011

The Landau level spectra and the quantum Hall effect of ABA-stacked multilayer graphenes are studied in the effective-mass approximation. The low-energy effective-mass Hamiltonian may be partially diagonalized into an approximate block-diagonal form, with each diagonal block contributing parabolic bands except for an additional block describing Dirac-like bands with a linear dispersion in a multilayer with an odd number of layers. We fully include the band parameters and, taking into account the symmetry of the lattice, we analyze their effect on the block-diagonal Hamiltonian. Next-nearest-layer couplings are shown to be particularly important in determining the low-energy spectrum and the phase diagram of the quantum Hall conductivity by causing energy shifts, level anticrossings, and valley splitting of the low-lying Landau levels. © 2011 American Physical Society. Source

Mitsui T.,Tohoku University
Nuclear Physics B - Proceedings Supplements | Year: 2011

KamLAND results, current status, and near-future plans are reviewed. For reactor and geoneutrino physics, reduction of the systematic uncertainties is underway, while taking subsequent data. For the detection of 7Be solar neutrinos, purification of the scintillator by distillation will start soon. © 2011 Elsevier B.V. Source

The objective of this study is to investigate age-related differences in recovered visual function in Royal College of Surgeons (RCS) rats transduced with the Channelrhodopsin-2 (ChR2) gene. An adeno-associated virus vector that contained ChR2 was injected intravitreously into young or aged RCS rats. After 4 months, visual evoked potentials were recorded. To estimate the transduction efficiencies, ChR2V-expressing cells and retrograde labeled retinal ganglion cells (RGCs) were counted. After photoreceptor degradation, immunohistochemistry was used to detect glial fibrillary acidic protein (GFAP) in the retinas. The amplitudes and latencies from young RCS rats were higher and shorter, respectively, than those from aged RCS rats. ChR2V was expressed in the RGCs of both groups of rats; there was no significant difference in the transduction efficiency of either group. However, the number of RGCs in aged RCS rats was significantly less than that in young RCS rats. In addition, strong GFAP immunoreactivity was observed after photoreceptor degeneration, whereas it was weaker in ChR2V-expressing RGCs. ChR2 transduction produced photosensitive RGCs in both young and aged rats. However, the degree of recovery depended on the age at the time of transduction. Source

Iwasaki T.,Tohoku University
Scientific Online Letters on the Atmosphere | Year: 2012

In the diagnosis of mass-weighted isentropic zonal mean (MIM), the mean- meridional circulation has a strong extratropical direct (ETD) cell in the northern- hemispheric winter, which turns from downward to equatorward around 45°N and isentropic zonal mean pressure of 850 hPa. The January mean equatorward flow in the extratopical lower troposphere is almost in balance with Eliassen-Palm (E-P) flux divergence for both climatology and interannual variability. This means that the zonal mean equatorward flow in the extratropical lower troposphere is the wave-induced circulation as well as the poleward flow in the stratosphere is. The interannual variation of January mean mass stream functions at (45°N, 850 hPa) positively (negatively) correlates with the zonal mean temperature in the lower troposphere north (south) of about 45°N, respectively. This is consistent with a simple thermodynamic consideration that the strong ETD circulation adiabatically warms up the lower troposphere due to the descending flow in the higher latitudes but cools it down due to the heat advection by the equatorward flow in the middle latitudes (~35°N). © 2012, the Meteorological Society of Japan. Source

Moon P.,Shanghai University | Koshino M.,Tohoku University
Physical Review B - Condensed Matter and Materials Physics | Year: 2014

We theoretically investigate the electronic structures of moiré superlattices arising in monolayer/bilayer graphene stacked on hexagonal boron nitride (hBN) in the presence and absence of magnetic field. We develop an effective continuum model from a microscopic tight-binding lattice Hamiltonian and calculate the electronic structures of graphene-hBN systems with different rotation angles. Using the effective model, we explain the characteristic band properties such as the gap opening at the corners of the superlattice Brillouin zone (mini-Dirac point). We also investigate the energy spectrum and quantum Hall effect of graphene-hBN systems in uniform magnetic field and demonstrate the evolution of the fractal spectrum as a function of the magnetic field. The spectrum generally splits in the valley degrees of freedom (K and K′) due to the lack of the inversion symmetry, and the valley splitting is more significant in bilayer graphene on hBN than in monolayer graphene on hBN because of the stronger inversion-symmetry breaking in bilayer. © 2014 American Physical Society. Source

Tanaka K.,Tohoku University
Cellular and Molecular Life Sciences | Year: 2013

Interaction of microtubules with kinetochores is fundamental to chromosome segregation. Kinetochores initially associate with lateral surfaces of microtubules and subsequently become attached to microtubule ends. During these interactions, kinetochores can move by sliding along microtubules or by moving together with depolymerizing microtubule ends. The interplay between kinetochores and microtubules leads to the establishment of bi-orientation, which is the attachment of sister kinetochores to microtubules from opposite spindle poles, and subsequent chromosome segregation. Molecular mechanisms underlying these processes have been intensively studied over the past 10 years. Emerging evidence suggests that the KNL1-Mis12-Ndc80 (KMN) network plays a central role in connecting kinetochores to microtubules, which is under fine regulation by a mitotic kinase, Aurora B. However, a growing number of additional molecules are being shown to be involved in the kinetochore- microtubule interaction. Here I overview the current range of regulatory mechanisms of the kinetochore-microtubule interaction, and discuss how these multiple molecules contribute cooperatively to allow faithful chromosome segregation. © 2012 Springer Basel AG. Source

RATIONALE:: Endothelial AMP-activated protein kinase (AMPK) plays an important role for vascular homeostasis and its role is impaired by vascular inflammation. However, the role of endothelial AMPK in the pathogenesis of pulmonary arterial hypertension (PAH) remains to be elucidated. OBJECTIVE:: To determine the role of endothelial AMPK in the development of PAH. METHODS AND RESULTS:: Immunostaining showed that endothelial AMPK is down-regulated in the pulmonary arteries of patients with PAH and hypoxia mouse model of pulmonary hypertension (PH). To elucidate the role of endothelial AMPK in PH, we used endothelial-specific AMPK-knockout mice (eAMPK), which were exposed to hypoxia. Under normoxic condition, eAMPK mice showed the normal morphology of pulmonary arteries compared with littermate controls (eAMPK). In contrast, development of hypoxia-induced PH was accelerated in eAMPK mice compared with controls. Furthermore, the exacerbation of PH in eAMPK mice was accompanied by reduced endothelial function, up-regulation of growth factors, and increased proliferation of pulmonary artery smooth muscle cells (PASMCs). Importantly, conditioned medium from endothelial cells promoted PASMC proliferation, which was further enhanced by treatment with AMPK inhibitor. Serum levels of inflammatory cytokines, including tumor necrosis factor-α and interferon-γ were significantly increased in PAH patients compared with healthy controls. Consistently, endothelial AMPK and cell proliferation were significantly reduced by treatment with serum from PAH patients compared with controls. Importantly, long-term treatment with metformin, an AMPK activator, significantly attenuated hypoxia-induced PH in mice. CONCLUSIONS:: These results indicate that endothelial AMPK is a novel therapeutic target for the treatment of PAH. © 2016 American Heart Association, Inc. Source

Fukudo S.,Tohoku University
Nature reviews. Gastroenterology & hepatology | Year: 2013

Cheng et al. recently reported that patients with IBS have impaired cardiac sympathetic and vagal response to colonic stimulation owing to the procedure of flexible sigmoidoscopy. The importance of this blunted response of the autonomic nervous system in patients with IBS was discussed alongside the basis of visceral perception. Source

Kitano R.,Tohoku University
Journal of High Energy Physics | Year: 2011

The hidden local symmetry is a successful model to describe the properties of the vector mesons in QCD. We point out that if we identify this hidden gauge theory as the magnetic picture of QCD, a linearly realized version of the model simultaneously describes color confinement and chiral symmetry breaking. We demonstrate that such a structure can be seen in the Seiberg dual picture of a softly broken supersymmetric QCD. The model possesses exact chiral symmetry and reduces to QCD when mass parameters are taken to be large. Working in the regime of the small mass parameters, we show that there is a vacuum where chiral symmetry is spontaneously broken and simultaneously the magnetic gauge group is Higgsed. If the vacuum we find persists in the limit of large mass parameters, one can identify the ρ meson as the massive magnetic gauge boson, that is an essential ingredient for color confinement. © SISSA 2011. Source

Dreyer I.,Polytechnic University of Mozambique | Uozumi N.,Tohoku University
FEBS Journal | Year: 2011

Potassium (K +) is the most abundant inorganic cation in plant cells. Unlike animals, plants lack sodium/potassium exchangers. Instead, plant cells have developed unique transport systems for K + accumulation and release. An essential role in potassium uptake and efflux is played by potassium channels. Since the first molecular characterization of K + channels from Arabidopsis thaliana in 1992, a large number of studies on plant potassium channels have been conducted. Potassium channels are considered to be one of the best characterized class of membrane proteins in plants. Nevertheless, knowledge on plant potassium channels is still incomplete. This minireview focuses on recent developments in the research of potassium transport in plants with a strong focus on voltage-gated potassium channels. Potassium (K +) is the most abundant inorganic cation in plant cells. An essential role in the uptake and efflux of potassium is played by potassium channels. This mini-review focuses on recent developments in research of potassium transport in plants with a strong focus on voltage-gated potassium channels © 2011 The Authors Journal compilation © 2011 FEBS. Source

Morohoshi K.,Tohoku University
Discovery medicine | Year: 2011

Hashimoto's thyroiditis, a common organ-specific autoimmune disease, is multifactorial in which both genetic susceptibility and environmental factors including infection play a critical role in its pathogenesis. Viral infection activates both the innate and adaptive immunity and is implicated as a trigger of Hashimoto's thyroiditis. Candidate viruses include hepatitis C virus and human parvovirus B19. Viral components, which are recognized by innate receptors including Toll-like receptors (TLRs), are detected in thyroid tissues and sera of patients with Hashimoto's thyroiditis. While conflicting results have been obtained regarding the role of TLRs in autoimmune diseases, our preliminary study suggested a contribution of TLR2 and dectin-1 in combination, TLR4, or TLR7 to the production of anti-thyroglobulin antibody in nonobese diabetic mice, a mouse model of Hashimoto's thyroiditis. Despite interesting circumstantial evidence, however, whether viral infection and innate receptors are involved in the development of Hashimoto's thyroiditis remains largely unclear. In this review, we summarize our knowledge regarding the role of viral infection and innate receptors in the etiology of Hashimoto's thyroiditis. © Discovery Medicine Source

Millius A.,University of California at San Francisco | Watanabe N.,Tohoku University | Weiner O.D.,University of California at San Francisco
Journal of Cell Science | Year: 2012

The SCAR/WAVE complex drives lamellipodium formation by enhancing actin nucleation by the Arp2/3 complex. Phosphoinositides and Rac activate the SCAR/WAVE complex, but how SCAR/WAVE and Arp2/3 complexes converge at sites of nucleation is unknown. We analyzed the single-molecule dynamics of WAVE2 and p40 (subunits of the SCAR/WAVE and Arp2/3 complexes, respectively) in XTC cells. We observed lateral diffusion of both proteins and captured the transition of p40 from diffusion to network incorporation. These results suggest that a diffusive 2D search facilitates binding of the Arp2/3 complex to actin filaments necessary for nucleation. After nucleation, the Arp2/3 complex integrates into the actin network and undergoes retrograde flow, which results in its broad distribution throughout the lamellipodium. By contrast, the SCAR/WAVE complex is more restricted to the cell periphery. However, with single-molecule imaging, we also observed WAVE2 molecules undergoing retrograde motion. WAVE2 and p40 have nearly identical speeds, lifetimes and sites of network incorporation. Inhibition of actin retrograde flow does not prevent WAVE2 association and disassociation with the membrane but does inhibit WAVE2 removal from the actin cortex. Our results suggest that membrane binding and diffusion expedites the recruitment of nucleation factors to a nucleation site independent of actin assembly, but after network incorporation, ongoing actin polymerization facilitates recycling of SCAR/WAVE and Arp2/3 complexes. © 2012. Source

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. Source

To elucidate the conduit processes controlling the amplitude of air pressure waves (Apw) from vulcanian eruptions at the Sakurajima volcano, Japan, we examine ash particles emitted by eruptions preceded by swarms of low-frequency B-type earthquakes (BL-swarms). We measure the water content of glassy ash, an indicator of shallow magma storage pressure, and vesicle textures, such as vesicle number density (VND). These data allow us to reconstruct the shallow conduit by comparing vesicularity with inferred pressure, and therefore depth, of magma storage. The results show that VND increases with depth, implying formation of a dense, outgassed magma cap underlain by more-vesicular, less-outgassed, magma. The VND and water content in the glassy ash positively correlate with the duration of BL-swarms, suggesting that such seismic signals reflect upward migration of deep gas- and vesicle-rich magma. Finally, it is determined that Apw positively correlates with VND, suggesting that the amplitude of the air pressure waves is controlled by the amount of accumulated gas- and bubble-rich magma below the dense magma cap. © 2013 Springer-Verlag Berlin Heidelberg. Source

Katoh Y.,Tohoku University | Omura Y.,Kyoto University
Journal of Geophysical Research: Space Physics | Year: 2013

By a series of self-consistent electron hybrid code simulations, we study the effect of the background magnetic field inhomogeneity on the generation process of whistler-mode chorus emissions. Chorus with rising tones are generated through nonlinear wave-particle interactions occurring around the magnetic equator. The mirror force plays an important role in the nonlinear interactions, and the spatial inhomogeneity of the background magnetic field is a key parameter of the chorus generation process. We have conducted numerical experiments with different spatial inhomogeneities to understand properties of the chorus generation process. We assume the same initial condition of energetic electrons at the magnetic equator in all simulation runs. The simulation results reveal that the spectral characteristics of chorus significantly vary depending on the magnetic field inhomogeneity. Whistler-mode emissions are generated and propagate away from the equator in all simulation runs, but distinct chorus elements with rising tones are only reproduced in the cases of small inhomogeneities. In the simulation that had the smallest inhomogeneity, we find excitation of broadband hiss-like emission (BHE) whose amplitudes are comparable to discrete chorus elements found in other simulation runs. The BHE consists of many wave elements with rising tones nonlinearly triggered in the region close to the magnetic equator. We show that the small spatial inhomogeneity of the background magnetic field results in the small threshold amplitude for the nonlinear wave growth and allows the triggering process of rising tone elements to emerge easily in the equatorial region of the magnetosphere. © 2013. American Geophysical Union. All Rights Reserved. Source

Imaji A.,Nara Forest Research Institute | Seiwa K.,Tohoku University
Oecologia | Year: 2010

Optimal carbon allocation to growth, defense, or storage is a critical trait in determining the shade tolerance of tree species. Thus, examining interspecific differences in carbon allocation patterns is useful when evaluating niche partitioning in forest communities. We hypothesized that shade-tolerant species allocate more carbon to defense and storage and less to growth compared to shade-intolerant species. In gaps and forest understory, we measured relative growth rates (RGR), carbon-based defensive compounds (condensed tannin, total phenolics), and storage compounds (total non-structural carbohydrate; TNC) in seedlings of two tree species differing in shade tolerance. RGR was greater in the shade-intolerant species, Castanea crenata, than in the shade-tolerant species, Quercusmongolica var. grosseserrata, in gaps, but did not differ between the species in the forest understory. In contrast, concentrations of condensed tannin and total phenolics were greater in Quercus than in Castanea at both sites. TNC pool sizes did not differ between the species. Condensed tannin concentrations increased with increasing growth rate of structural biomass (GRstr) in Quercus but not in Castanea. TNC pool sizes increased with increasing GRstr in both species, but the rate of increase did not differ between the species. Accordingly, the amount of condensed tannin against TNC pool sizes was usually higher in Quercus than in Castanea. Hence, Quercus preferentially invested more carbon in defense than in storage. Such a large allocation of carbon to defense would be advantageous for a shade-tolerant species, allowing Quercus to persist in the forest understory where damage from herbivores and pathogens is costly. In contrast, the shade-intolerant Castanea preferentially invested more carbon in growth rather than defense (and similar amounts in storage as Quercus), ensuring establishment success in gaps, where severe competition occurs for light among neighboring plants. These contrasting carbon allocation patterns are closely associated with strategies for persistence in these species' respective habitats. © Springer-Verlag 2009. Source

Yamaya T.,Tohoku University | Kusano M.,RIKEN
Journal of Experimental Botany | Year: 2014

The functions of the three isoenzymes of cytosolic glutamine synthetase (GS1;1, GS1;2, and GS1;3) and two NADH-glutamate synthases (NADH-GOGAT1 and NADH-GOGAT2) in rice (Oryza sativa L.) were characterized using a reverse genetics approach and spatial expression of the corresponding genes. OsGS1;2 and OsNADH-GOGAT1 were mainly expressed in surface cells of rice roots in an NH4+-dependent manner. Disruption of either gene by the insertion of endogenous retrotransposon Tos17 caused reduction in active tiller number and hence panicle number at harvest. Re-introduction of OsGS1;2 cDNA under the control of its own promoter into the knockout mutants successfully restored panicle number to wild-type levels. These results indicate that GS1;2 and NADH-GOGAT1 are important in the primary assimilation of NH4+ taken up by rice roots. OsGS1;1 and OsNADH-GOGAT2 were mainly expressed in vascular tissues of mature leaf blades. OsGS1;1 mutants showed severe reduction in growth rate and grain filling, whereas OsNADH-GOGAT2 mutants had marked reduction in spikelet number per panicle. Complementation of phenotypes seen in the OsGS1;1 mutant was successfully observed when OsGS1;1 was re-introduced. Thus, these two enzymes could be important in remobilization of nitrogen during natural senescence. Metabolite profling data showed a crucial role of GS1;1 in coordinating metabolic balance in rice. Expression of OsGS1:3 was spikelet-specific, indicating that it is probably important in grain ripening and/or germination. Thus, these isoenzymes seem to possess distinct and non-overlapping functions and none was able to compensate for the individual function of another. © The Author 2014. Source

Yamasaki K.,Tohoku University | Gallo R.L.,University of California at San Diego
Journal of Investigative Dermatology Symposium Proceedings | Year: 2011

Rosacea is a common and chronic inflammatory skin disease most frequently seen in groups of genetically related individuals. Although the symptoms of rosacea are heterogeneous, they are all related by the presence of characteristic facial or ocular inflammation involving both the vascular and tissue stroma. Until recently, the pathophysiology of this disease was limited to descriptions of a wide variety of factors that exacerbate or improve disease. Recent molecular studies show a common link between the triggers of rosacea and the cellular response, and these observations suggest that an altered innate immune response is involved in disease pathogenesis. Understanding rosacea as a disorder of innate immunity explains the benefits of current treatments and suggests new therapeutic strategies for alleviating this disease. © 2011 The Society for Investigative Dermatology. Source

Nakahara H.,Tohoku University
Bulletin of the Seismological Society of America | Year: 2013

I study S-wave energy radiation in higher frequencies of 1-8 Hz from the 2011 Mw 9.0 Off the Pacific Coast of Tohoku, Japan, earthquake (hereafter called the Tohoku-Oki earthquake) based on a seismogram envelope inversion method. I first evaluate two medium parameters of scattering attenuation and intrinsic absorption for S waves using spatial and temporal distributions of seismic energy from aftershock records, which are necessary for calculating Green's functions. Next, applying the envelope inversion method to 27 near-field strong-motion records from the mainshock, I estimate the S-wave energy radiation from 40 subfaults on the fault of 500 km × 250 km. Each subfault is allowed to rupture for eight consecutive source time windows. Rupture velocity and the duration of energy radiation for each time window are determined by a grid search to be 2:5 km=s and 8.0 s, respectively. Energy radiated from the entire fault is 5:8 × 1016 J for 1-2Hz, 4:5 × 1016 J for 2-4Hz, 1:5 × 1016 J for 4-8 Hz, and totaling 1:2 × 1017 J in the 1-8 Hz range. Strong energy emanated twice from greater depths of the off-Miyagi region, corresponding to two peaks seen at the northern stations. And energy radiation at greater depths off the Fukushima-Ibaraki border is compatible with a single peak found at the southern stations. Strong high-frequency radiations at greater depths strikingly contrast with large slips at shallower depths estimated in lower frequencies. This frequencydependent rupture may accord with structural changes along the dip direction. Source

Toda S.,Tohoku University | Tsutsumi H.,Kyoto University
Bulletin of the Seismological Society of America | Year: 2013

The gigantic Mw 9.0 11 March 2011 Tohoku-oki earthquake suddenly changed the overriding inland area to an extensional stress regime and triggered massive seismic swarms in the coastal region. The largest earthquake of Mw 6.6 struck southern Fukushima on 11 April 2011 and ruptured two previously mapped faults, the northwest (NW)-trending Yunodake fault and the north-northwest (NNW)-trending Itozawa fault. Clear 15-km-long and 14-km-long surface ruptures appeared along both faults, respectively, exhibiting a predominantly normal sense of slip, down to the west. The maximum vertical offset on the Yunodake fault is 0:8 m, whereas that on the Itozawa fault is 2:1 m. The Itozawa fault rupture is in part marked by uphill-facing scarps, which is discordant with the large-scale topography but consistent with saddled ridges and ponded alluvium. The Yunodake fault, which bounds a Neogene half-graben structure juxtaposing Mesozoic metamorphic rocks against Neogene sedimentary rocks, shows left-lateral deflections of streams. Seismological data and interviews of local residents revealed that the two subparallel faults ruptured simultaneously. Based on the location of its hypocenter, we, however, interpret that the Itozawa rupture was primary and then triggered normal faulting on the Yunodake fault under the heightened Coulomb stress caused by the preceding Tohoku-oki earthquake. Our paleoseismic trench across the Itozawa fault exposed evidence for a penultimate earthquake that occurred sometime between 12,620 and 17,410 cal yr B.P. There is no evidence that the Itozawa fault ruptured during or immediately after the A.D. 869 Jogan earthquake, which is believed to be the penultimate giant megathrust earthquake along the Japan trench. Source

Itoi E.,Tohoku University
Journal of Orthopaedic Science | Year: 2013

Rotator cuff tear is one of the most common shoulder diseases. It is interesting that some rotator cuff tears are symptomatic, whereas others are asymptomatic. Pain is the most common symptom of patients with a tear. Even in patients with an asymptomatic tear, it may become symptomatic with an increase in tear size. Physical examination is extremely important to evaluate the presence, location, and extent of a tear. It also helps us to understand the mechanism of pain. Conservative treatment often works. Patients with well-preserved function of the supraspinatus and infraspinatus are the best candidates for conservative treatment. After a successful conservative treatment, the symptom once disappeared may come back again. This recurrence of symptoms is related to tear expansion. Those with high risk of tear expansion and those with less functional rotator cuff muscles are less likely to respond to conservative treatment. They may need a surgical treatment. © 2012 The Japanese Orthopaedic Association. Source

Itoh K.,Hirosaki University | Mimura J.,Hirosaki University | Yamamoto M.,Tohoku University
Antioxidants and Redox Signaling | Year: 2010

An antioxidant response element (ARE) or an electrophile responsive element (EpRE) regulate the transcriptional induction of a battery of drug-detoxifying enzymes that are protective against electrophiles. Based on the high similarity of the ARE consensus sequence to an erythroid gene regulatory element NF-E2 binding site, we have found that the transcription factor Nrf2 is indispensable for the ARE-mediated induction of drug-metabolizing enzymes. Recent genome-wide analysis demonstrated that Nrf2 regulates hundreds of genes that are involved in the cytoprotective response against oxidative stress. In-depth analysis of Nrf2 regulatory mechanisms has led us to the discovery of a novel protein, which we have named Keap1. Keap1 suppresses Nrf2 activity by specifically binding to its evolutionarily conserved N-terminal Neh2 regulatory domain. In this review article, we summarize the findings and observations that have lead to the discovery of the Nrf2-Keap1 system. Furthermore, we briefly discuss the function of the Nrf2-Keap1 system under the regulation of the endogenous electrophilic compound 15-deoxy-Δ12,14-prostaglandin J2. We propose that Nrf2-Keap1 plays a significant physiological role in the response to endogenous, environmental, and pharmacological electrophiles. © 2010 Mary Ann Liebert, Inc. Source

Kohno M.,Tohoku University
Journal of Clinical Biochemistry and Nutrition | Year: 2010

Electron spin resonance (ESR) spectroscopy has been widely applied in the research of biological free radicals for quantitative and qualitative analyses of reactive oxygen species (ROS) and reactive nitrogen species (RNS). The ESR spin-trapping method was developed in the early 1970s and enabled the analysis of short-lived free radicals. This method is now widely used as one of the most powerful tools for free radical studies. In this report, some of the studies that applied ESR for the measurement of ROS and RNS during oxidative stress are discussed. Source

Shimokawa H.,Tohoku University | Tsutsui M.,The University of Okinawa
Pflugers Archiv European Journal of Physiology | Year: 2010

Nitric oxide (NO) is produced in almost all tissues and organs, exerting a variety of biological actions under both physiological and pathological conditions. NO is synthesized by three distinct NO synthase (NOS) isoforms (neuronal, inducible, and endothelial NOS), all of which are expressed in the human cardiovascular system. Although the regulatory roles of NOSs in cardiovascular diseases have been described in pharmacological studies with selective and non-selective NOS inhibitors, the specificity of the NOS inhibitors continues to be an issue of debate. To overcome this issue, genetically engineered animals have been used. All types of NOS gene-deficient animals, including singly, doubly, and triply NOS-deficient mice, and various types of NOS gene-transgenic (TG) animals, including conditional and non-conditional TG mice bearing endothelium-specific or cardiomyocyte-specific overexpression of each NOS gene, have thus been developed. The roles of individual NOS isoforms as well as the entire NOS system in the cardiovascular system have been extensively investigated in those mice, providing pivotal insights into an understanding of the pathophysiology of NOSs in human cardiovascular diseases. Based on studies with the murine NOS genetic models, this review briefly summarizes the latest knowledge of NOSs and cardiovascular diseases. © 2010 Springer-Verlag. Source

Shimokawa H.,Tohoku University
Pflugers Archiv European Journal of Physiology | Year: 2010

The endothelium plays an important role in maintaining cardiovascular homeostasis by synthesizing and releasing several vasodilating substances, including vasodilator prostaglandins, nitric oxide (NO), and endothelium-derived hyperpolarizing factor (EDHF). Since the first report on the existence of EDHF, several substances/mechanisms have been proposed for the nature of EDHF, including epoxyeicosatrienoic acids (metabolites of arachidonic P450 epoxygenase pathway), K ions, and electrical communications through myoendothelial gap junctions. We have demonstrated that endothelium-derived hydrogen peroxide (H2O2) is an EDHF in animals and humans. For the synthesis of H2O2/EDHF, endothelial NO synthase system that is functionally coupled with Cu,Zn-superoxide dismutase plays a crucial role. Importantly, endothelium-derived H2O2 plays important protective roles in the coronary circulation, including coronary autoregulation, protection against myocardial ischemia/reperfusion injury, and metabolic coronary vasodilatation. Indeed, our H2O2/EDHF theory demonstrates that endothelium-derived H2O2, another reactive oxygen species in addition to NO, plays important roles as a redox-signaling molecule to cause vasodilatation as well as cardioprotection. In this review, we summarize our current knowledge on H2O 2/EDHF regarding its identification and mechanisms of synthesis and actions. © 2010 Springer-Verlag. Source

Fuse N.,Tohoku University
Tohoku Journal of Experimental Medicine | Year: 2010

Glaucoma is the leading cause of visual impairment and blindness throughout the world. Primary open angle glaucoma (POAG; MIM 137760) is the main type of glaucoma in most populations, and more than 20 genetic loci for POAG have been reported. Only three causative genes have been identified in these loci, viz. myocilin (MYOC), optineurin (OPTN), and WD repeat domain 36 (WDR36). However, mutations in these genes account for only a small percentage of the patients with POAG. Some of these glaucoma cases have a Mendelian inheritance pattern, and a considerable fraction of the cases result from a large number of variants in several genes each contributing small effects. Glaucoma is considered to be a common disease such as diabetes mellitus, coronary disease, Crohn disease, and several common cancers. The main technological approaches used to identify the genes associated with glaucoma are the candidate gene approach, linkage analysis, case-control association study, and genome-wide association study. Association studies have found about 27 genes related to POAG, but the glaucoma-causing effects of these genes need to be investigated in more detail. The current trend is to use case-control association studies or genome-wide association studies to map the genes associated with glaucoma. Such studies are expected to greatly advance our understanding of the genetic basis of glaucoma, and to provide information on the effectiveness of glaucoma therapy. This review gives an overview on the genetic aspects of glaucoma. © 2010 Tohoku University Medical Press. Source

Katoh Y.,Tohoku University | Omura Y.,Kyoto University
Journal of Geophysical Research: Space Physics | Year: 2011

The frequency and amplitude characteristics of chorus emissions are studied by performing electron hybrid code simulations with different initial number densities of energetic electrons. Chorus emissions with rising tones are generated in all simulation runs except for the simulation assuming the lowest number density. The frequency sweep rates of reproduced chorus vary depending on the variation of the wave amplitude of respective chorus elements. We find that the theoretically estimated frequency sweep rates are consistent with the simulation results. The simulation results reveal that the characteristic frequency variation of chorus elements showing rising tones are formed at the region very close to the magnetic equator while the wave amplitudes of chorus elements are significantly amplified through their propagation away from the equator. The spatial scale of the region where the observed explosive wave growth varies in each simulation run, corresponding to the difference of the wave amplitudes of reproduced chorus elements. We estimate the spatial scale hc, a measure of the spatial extent of the generation region derived from the nonlinear wave growth theory, using parameters of the simulation runs and find its consistency with the simulation results. We also analyze the energy spectra of reproduced chorus elements in the simulation results and find that the spectra of chorus are essentially different from those predicted by the linear growth rates in the frequency domain. These results clearly demonstrate that the nonlinear wave-particle interaction governs the chorus generation mechanism. Copyright 2011 by the American Geophysical Union. Source

Mori E.,Tohoku University | Ikeda M.,Kumamoto University | Kosaka K.,Yokohama City University
Annals of Neurology | Year: 2012

Objective: Because cholinergic deficits are prominent in dementia with Lewy bodies (DLB), we investigated the effects of a cholinesterase inhibitor, donepezil, in such patients in a randomized, double-blind, placebo-controlled exploratory phase 2 trial. Methods: One-hundred forty patients with DLB, recruited from 48 specialty centers in Japan, were randomly assigned to receive placebo or 3, 5, or 10mg of donepezil hydrochloride daily for 12 weeks (n = 35, 35, 33, and 37, respectively). Effects on cognitive function were assessed using the Mini-Mental State Examination (MMSE) and several domain-specific neuropsychological tests. Changes in behavior were evaluated using the Neuropsychiatric Inventory, caregiver burden using the Zarit Caregiver Burden Interview, and global function using the Clinician's Interview-Based Impression of Change-plus Caregiver Input (CIBIC-plus). Safety measures included the Unified Parkinson's Disease Rating Scale part III. Results: Donepezil at 5 and 10mg/day was significantly superior to placebo on both the MMSE (5mg: mean difference, 3.8; 95% confidence interval [CI], 2.3-5.3; p < 0.001; 10 mg: mean difference, 2.4; 95% CI, 0.9-3.9; p = 0.001) and CIBIC-plus (p < 0.001 for each); 3mg/day was significantly superior to placebo on CIBIC-plus (p < 0.001), but not on the MMSE (p = 0.017). Significant improvements were found also in behavioral measures (p < 0.001) at 5 and 10mg/day and caregiver burden (p = 0.004) at 10 mg/day. The safety results were consistent with the known profile of donepezil and similar among groups. Interpretation: Donepezil at 5 and 10mg/day produces significant cognitive, behavioral, and global improvements that last at least 12 weeks in DLB patients, reducing caregiver burden at the highest dose. Donepezil is safe and well tolerated. © 2012 American Neurological Association. Source

Combretastatins interrupt blood flow of solid tumor vascular networks and lead to necrosis by blocking nutrients. However, tumors recover from tumor blood flow interruption-induced damage and develop viable rims. To investigate why cancer recurs and its prevention, we used a combretastatin derivative, Cderiv (=AC7700), and analyzed changes in tumor-host interface (T-HI) vessels, which were closest to cancer cells in the tumor margin after tumor vessel disruption, and the microenvironment surrounding them. Treatment with Cderiv (10 mg/kg) interrupted tumor blood flow in all regions of LY80 (a variant of Yoshida sarcoma) tumor, but not T-HI vessel blood flow. The same Cderiv dose given 72 h after 5 Gy irradiation stopped T-HI vessel blood flow and prevented cancer recurrence. Treatment in the reverse order, however, did not affect T-HI vessel blood flow. The greatest difference between the two treatments was the occurrence of gradual T-HI edema with the former. Severe T-HI edema compressed T-HI blood vessels, so that circulation stopped. Thus, the distance between a tumor margin and its nearest functioning host vessel became much larger, and the tumor marginal region became a microenvironment that lacked a nutritional supply. Cancer cells in tumor margins received nutrients through two circulation routes: tumor vessels and T-HI vessels. Our starvation methods, which involved treatment with Cderiv 72 h after 5 Gy irradiation, blocked both circulation routes and may have great potential as a clinical strategy to prevent cancer recurrence. © 2014 The Authors. Cancer Science published by Wiley Publishing Asia Pty Ltd on behalf of Japanese Cancer Association. Source

The systematic observation of pairs of Δ I = 1 bands is reviewed. Experimental and theoretical studies of these bands in terms of spontaneous formation of chirality in rotating nuclei are discussed. © 2010 Elsevier B.V. All rights reserved. Source

Aoki M.,Tohoku University | Kanemura S.,University of Toyama | Seto O.,Hokkai Gakuen University
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2010

In a scenario of Higgs portal dark matter, Higgs exchange processes are essential for both dark matter annihilation in the early Universe and direct search experiments. The CDMS II Collaboration has recently released their final results on direct dark matter searches. We study a scalar dark matter model with multi-Higgs doublets under the constraint from the CDMS II results and also from the WMAP data. We find that the possible maximal value for the branching ratio of the invisible decay of the Higgs boson can be significantly greater than that in the Higgs portal model with one Higgs doublet, in particular, for the case of the so-called Type-X Yukawa interaction. Therefore, the search for the invisible decay of the Higgs boson at the CERN Large Hadron Collider and future collider experiments would provide useful information not only for the nature of dark matter but also for the structure of the Higgs sector even without directly detecting any extra scalar boson. © 2010 Elsevier B.V. All rights reserved. Source

Kodama S.,Tohoku University | Negishi M.,National Health Research Institute
Drug Metabolism Reviews | Year: 2013

Pregnane X receptor (PXR), an orphan member of the nuclear receptor superfamily, is a major xeno-sensing transcription factor. In response to xenobiotic exposure, PXR regulates genes involved in the metabolism and transport of xenobiotics to protect the body from their harmful effects. Recent progress has revealed that PXR responds not only to such external signals but also to internal signals to help the body adapt to changes in the internal environment, including dysregulation of the immune system. PXR responds to external and internal signals by up- or down-regulating certain metabolic pathways and cellular signals through gene regulation. PXR is a potential therapeutic target for inflammatory as well as metabolic diseases, although its activation may also have unfavorable effects on human health. This review will discuss the recent progress in the understanding of the physiological and pathophysiological roles of PXR and their implications in human diseases and drug therapy by elucidating the molecular mechanisms underlying PXR-mediated gene regulation. © 2013 Informa Healthcare USA, Inc. All rights reserved: reproduction in whole or part not permitted. Source

We proposed a new anisotropy function of kinetic coefficient for the phase-field simulations in two-dimension. The anisotropy function has minima at arbitrary polar angles. We carried out phase-field simulations of solidification of binary alloy with the new anisotropy function and found that the calculated growth form agreed with the kinetic Wulff shape, which is the exact solution determined by the anisotropy function. With the new anisotropy function, the kinetic Wulff shape is not necessary to be regular polygons but can be an arbitrary shape with any face angles. In addition, we introduced a curvature parameter with the aim of optimizing the anisotropy function. We found that the kinetic Wulff shape with flat facets was reproduced when the curvature parameter was at a standard value of about 20. The optimization based on the curvature parameter is applicable to other anisotropy functions. We concluded that our anisotropy function and the concept of the curvature parameter give us a great opportunity to simulate more general shapes of crystals. © 2013 Elsevier B.V. All rights reserved. Source

Yamada Y.,Tohoku University
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2010

New heavy particles in an SU (2)L multiplet, sometimes introduced in extensions of the standard model, have highly degenerate tree-level mass M if their couplings to the Higgs bosons are very small or forbidden. However, loop corrections may generate the gauge-symmetry-breaking mass splitting within the multiplet, which does not vanish in the large M limit due to the threshold singularity. We calculate the electroweak contribution to the mass splitting for a heavy fermion multiplet, to the two-loop order. Numerically, two-loop electroweak contributions are typically O (MeV). © 2009 Elsevier B.V. All rights reserved. Source

Qi X.,Nankai University | Guo H.,Nankai University | Li L.,Nankai University | Smith Jr. R.L.,Tohoku University
ChemSusChem | Year: 2012

Carbonaceous solid (CS) catalysts with -SO3H, -COOH, and phenolic -OH groups were prepared by incomplete hydrothermal carbonization of cellulose followed by either sulfonation with H2SO4 to give carbonaceous sulfonated solid (CSS) material or by both chemical activation with KOH and sulfonation to give activated carbonaceous sulfonated solid (a-CSS) material. The obtained carbon products (CS, CSS, and a-CSS) were amorphous; the CSS material had a small surface area (<0.5 m2 g-1) and a high -SO3H group concentration (0.953 mmol g-1), whereas the a-CSS material had a large surface area (514 m 2 g-1) and a low -SO3H group concentration (0.172 mmol g-1). The prepared materials were evaluated as catalysts for the dehydration of fructose to 5-hydroxymethylfurfural (5-HMF) in the ionic liquid 1-butyl-3-methylimidazolium chloride ([BMIM][Cl]). Remarkably high 5-HMF yields (83 %) could be obtained efficiently (80°C and 10 min reaction time). CSS and a-CSS catalysts had similar catalytic activities and efficiencies for the conversion of fructose to 5-HMF in [BMIM][Cl]; this could be explained by the trade-off between -SO3H group concentration (high for CSS) and surface area (high for a-CSS). The cellulose-derived catalysts and ionic liquid exhibited constant activity for five successive recycles, and thus, the methods developed provide a renewable strategy for biomass conversion. © 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Fukumoto M.,Tohoku University
Pathology International | Year: 2014

The effects of radiation on human health have been a major concern, especially after the Fukushima Daiichi Nuclear Power Plant (FNPP) accident. We can determine these effects only from radiological disasters. The radiological contrast medium Thorotrast is known to induce hepatic cancers decades after injection. Using archival materials from Thorotrast patients, we performed molecular pathological studies to elucidate carcinogenic mechanisms of internal radiation exposure. It is emphasized here that radiation-induced cancers are a complex consequence of biological response to radiation and ingested radionuclides. We further expanded the study to establish clinically relevant radioresistant cancer cells in order to develop more effective and less harmful radiation therapy. We also found that cancer cells can acquire radioresistance by low-dose fractionated radiation within one month. The FNPP accidents prompted us to collect tissue samples from animals in and around the evacuation zone in order to construct a tissue bank. The final goal of the bank is to enable research that will contribute to the common understanding of radioprotection. © 2014 Japanese Society of Pathology and Wiley Publishing Asia Pty Ltd. Source

VARP (VPS9-ankyrin-repeat protein, also known as ANKRD27) was originally identified as an N-terminal VPS9 (vacuolar protein sorting 9)-domain-containing protein that possesses guanine nucleotide exchange factor (GEF) activity toward small GTPase Rab21 and contains two ankyrin repeat (ANKR) domains in its central region. A number of VARP-interacting molecules have been identified during the past five years, and considerable attention is now being directed to the multiple roles of VARP in endosomal trafficking. More specifically, VARP is now known to interact with three different types of key membrane trafficking regulators, i.e. small GTPase Rabs (Rab32, Rab38 and Rab40C), the retromer complex (a sorting nexin dimer, VPS26, VPS29 and VPS35) and R-SNARE VAMP7. By binding to several of these molecules, VARP regulates endosomal trafficking, which underlies a variety of cellular events, including melanogenic enzyme trafficking to melanosomes, dendrite outgrowth of melanocytes, neurite outgrowth and retromer-mediated endosome-to-plasma membrane sorting of transmembrane proteins. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd. Source

Louzguine-Luzgin D.V.,Tohoku University
Journal of Alloys and Compounds | Year: 2014

The phenomenon of vitrification on cooling, also called the glass-transition still remains not fully understood. Recent studies by different techniques were performed in order to shed light on this and on the converse phenomenon of devitrification. Devitrification may either lead to the formation of a supercooled liquid, a crystal(s) or a quasicrystal(s). The present paper is a review of recent findings on the processes of vitrification and devitrification in metallic glasses. © 2012 Elsevier B.V. All rights reserved. Source

Georgy C.,Keele University | Saio H.,Tohoku University | Meynet G.,University of Geneva
Monthly Notices of the Royal Astronomical Society: Letters | Year: 2014

Recent stellar evolution computations show that the blue supergiant (BSG) stars could come from two distinct populations: a first group arising from massive stars that just left the main sequence and are crossing the Hertzsprung-Russell diagram (HRD) towards the red supergiant (RSG) branch, and a second group coming from stars that have lost considerable amount of mass during the RSG stage and are crossing the HRD for a second time towards the blue region. Due to very different luminosity-to-mass ratio, only stars from the second group are expected to have excited pulsations observable at the surface. In a previous work, we have shown that our models were able to reproduce the pulsational properties of BSGs. However, these models failed to reproduce the surface chemical composition of stars evolving back from an RSG phase. In this Letter, we show how the use of the Ledoux criterion instead of the Schwarzschild one for convection allows us to significantly improve the agreement with the observed chemical composition, while keeping the agreement with the pulsation periods. This gives some support to the Ledoux criterion. © 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. Source

Qiao J.,Donghua University | Liu Y.,Tohoku University | Hong F.,Donghua University | Zhang J.,Donghua University | Zhang J.,National Research Council Canada
Chemical Society Reviews | Year: 2014

This paper reviews recent progress made in identifying electrocatalysts for carbon dioxide (CO2) reduction to produce low-carbon fuels, including CO, HCOOH/HCOO-, CH2O, CH4, H 2C2O4/HC2O4-, C2H4, CH3OH, CH3CH2OH and others. The electrocatalysts are classified into several categories, including metals, metal alloys, metal oxides, metal complexes, polymers/clusters, enzymes and organic molecules. The catalyts' activity, product selectivity, Faradaic efficiency, catalytic stability and reduction mechanisms during CO2 electroreduction have received detailed treatment. In particular, we review the effects of electrode potential, solution-electrolyte type and composition, temperature, pressure, and other conditions on these catalyst properties. The challenges in achieving highly active and stable CO2 reduction electrocatalysts are analyzed, and several research directions for practical applications are proposed, with the aim of mitigating performance degradation, overcoming additional challenges, and facilitating research and development in this area. © The Royal Society of Chemistry. Source

Sato Y.,Tohoku University
Journal of Atherosclerosis and Thrombosis | Year: 2014

The functional integrity of the vascular endothelium is an essential component required for the maintenance of vascular health, thus counteracting the onset of vascular diseases, including atherosclerosis and vascular complications of diabetes. In light of this important role, the vascular endothelium is expected to have a self-defense system. One candidate factor of such a system is vasohibin-1 (VASH1), a protein that is preferentially expressed in vascular endothelial cells (ECs). The unique features of VASH1 are its anti-angiogenic activity and ability to promote the stress tolerance and survival of ECs. This review summarizes current knowledge regarding VASH1 in terms of its roles in maintaining vascular integrity and protecting the vasculature against various forms of stress. © 2015, Japan Atherosclerosis Society. All rights reserved. Source

Takeda T.,Daiichi Sankyo | Terada M.,Tohoku University
Journal of the American Chemical Society | Year: 2013

Chiral bis(guanidino)iminophosphoranes were designed and synthesized as chiral uncharged organosuperbase catalysts that facilitate activation of less-acidic pro-nucleophiles. The newly developed bis(guanidino) iminophosphoranes, which possess the highest basicity among chiral organocatalysts reported to date, were proven to be a superb class of chiral organosuperbases by reaction of azodicarboxylates with 2-alkyltetralones and their analogues as the less acidic pro-nucleophiles. © 2013 American Chemical Society. Source

Ito S.,Tohoku University
Clinical and Experimental Nephrology | Year: 2012

Chronic kidney disease (CKD), as defined by reduced glomerular filtration rate (<60 ml/min/1.73 m 2) and/or the presence of renal damage for >3 months, is a significant threat for public health in modern societies. Recent epidemiological studies have demonstrated that CKD is a significant risk for cardiovascular events independently of classical risk factors such as hypertension, dyslipidemia and diabetes. The mechanisms by which CKD increases the risk of cardiovascular events are currently under intensive investigation. Among various components of CKD, microalbuminuria is of particular interest, because it is a significant risk factor not only in diabetic and hypertensive subjects but also in the general population. Microalbuminuria is also closely associated with salt sensitivity of blood pressure, and the salt sensitivity is an independent risk factor for cardiovascular disease even in normotensive subjects. Several factors are likely to be involved in such associations, including the renin-angiotensin system (RAS), oxidative stress and inflammation. In addition, there may be more specific hemodynamic mechanisms in the kidney and other vital organs underlying these associations. This review describes 'the strain vessel hypothesis' as a possible mechanism for cerebrocardiorenal connections. In addition we discuss the significance of underlying diseases as cardiovascular risks of CKD as well as the role of RAS inhibition in the management of CKD patients. © 2011 Japanese Society of Nephrology. Source

Yuge T.,Tohoku University
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2010

We derive general properties of the linear-response functions of nonequilibrium steady states in Langevin systems. These correspond to extension of the results which were recently found in Hamiltonian systems. We discuss one of the properties, the sum rule for the response function, in particular detail. We show that the sum rule for the response function of the velocity holds in the underdamped case, whereas it is violated in the overdamped case. This implies that the overdamped Langevin models should be used with great care. We also investigate the relation of the sum rule to an equality on the energy dissipation in nonequilibrium Langevin systems, which was derived by Harada and Sasa. © 2010 The American Physical Society. Source

Hotta M.,Tohoku University
Journal of Physics A: Mathematical and Theoretical | Year: 2010

It is well known that usual quantum teleportation protocols cannot transport energy. Recently, new protocols called quantum energy teleportation (QET) have been proposed, which transport energy by local operations and classical communication with the ground states of many-body quantum systems. In this paper, we compare two different QET protocols for transporting energy with the electromagnetic field. In the first protocol, a 1/2 spin (a qubit) is coupled with the quantum fluctuation in the vacuum state and measured in order to obtain one-bit information about the fluctuation for the teleportation. In the second protocol, a harmonic oscillator is coupled with the fluctuation and measured in order to obtain continuous-variable information about the fluctuation. In the spin protocol, the amount of teleported energy is suppressed by an exponential damping factor when the amount of input energy increases. This suppression factor becomes power damping in the case of the harmonic oscillator protocol. Therefore, it is concluded that obtaining more information about the quantum fluctuation leads to teleporting more energy. This result suggests a profound relationship between energy and quantum information. © 2010 IOP Publishing Ltd. Source

Miura Y.,Tohoku University
The Tohoku journal of experimental medicine | Year: 2011

The Miyagi Study is an epidemiological study of malignant lymphoma, including immunological and genetic analyses, constructed by a population-based registration system covering Miyagi prefecture, Japan. A total of 1,552 newly diagnosed cases in Miyagi between 2002 and 2008 were enrolled in this study; 75% were B-cell lymphomas, 19% were T-cell and natural killer-cell (T/NK-cell) lymphomas, and 5% were Hodgkin's lymphomas. The most frequent subtype of B-cell lymphoma is diffuse large B-cell lymphoma, followed by follicular lymphoma and extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (51%, 24% and 8%, respectively). Thus, follicular lymphoma accounts for 18.2% of newly diagnosed cases in Miyagi; unexpectedly, its frequency is similar to that reported in Western countries. The common subtypes of T/NK-cell lymphoma are peripheral T-cell lymphoma, angioimmunoblastic T-cell lymphoma, and adult T-cell leukemia/lymphoma (30%, 15% and 14%, respectively). Most of the data are similar to those reported in Asian countries, except for follicular lymphoma. We also analyzed the CD20 expression in B-cell lymphomas by flow cytometry for the cell membrane expression and by immunohistochemistry for the cytoplasmic expression. The cell membrane expression of CD20 protein may determine the susceptibility of B-cell lymphomas to anti-CD20 antibody therapy. The lack of CD20 expression was confirmed by both methods in 4 cases of 585 newly diagnosed cases (0.7%) and in 5 of 67 recurrent cases (7.5%). Furthermore, 23 cases (6.5%) showed the discrepancy of CD20 expression between both methods. The Miyagi Study has revealed the latest epidemiological features of malignant lymphoma in Japan. Source

Shinohara N.,University of York | Shinohara N.,Tohoku University | Taylor C.,University of York | Taylor C.,University of Cambridge | And 2 more authors.
PLoS Biology | Year: 2013

Plants continuously extend their root and shoot systems through the action of meristems at their growing tips. By regulating which meristems are active, plants adjust their body plans to suit local environmental conditions. The transport network of the phytohormone auxin has been proposed to mediate this systemic growth coordination, due to its self-organising, environmentally sensitive properties. In particular, a positive feedback mechanism termed auxin transport canalization, which establishes auxin flow from active shoot meristems (auxin sources) to the roots (auxin sinks), has been proposed to mediate competition between shoot meristems and to balance shoot and root growth. Here we provide strong support for this hypothesis by demonstrating that a second hormone, strigolactone, regulates growth redistribution in the shoot by rapidly modulating auxin transport. A computational model in which strigolactone action is represented as an increase in the rate of removal of the auxin export protein, PIN1, from the plasma membrane can reproduce both the auxin transport and shoot branching phenotypes observed in various mutant combinations and strigolactone treatments, including the counterintuitive ability of strigolactones either to promote or inhibit shoot branching, depending on the auxin transport status of the plant. Consistent with this predicted mode of action, strigolactone signalling was found to trigger PIN1 depletion from the plasma membrane of xylem parenchyma cells in the stem. This effect could be detected within 10 minutes of strigolactone treatment and was independent of protein synthesis but dependent on clathrin-mediated membrane trafficking. Together these results support the hypothesis that growth across the plant shoot system is balanced by competition between shoot apices for a common auxin transport path to the root and that strigolactones regulate shoot branching by modulating this competition. © 2013 Shinohara et al. Source

Muroi Y.,Tohoku University
Journal of Computational Finance | Year: 2012

The prices of credit derivatives within multiple defaultable entities are evaluated in this paper using the asymptotic expansion approach. The theoretical prices of credit derivatives such as credit default swaptions are often analytically intractable. However, recent developments in the asymptotic expansion method permit an easier evaluation of these contingent claims. This paper provides the prices of credit default swaps and swaptions, taking account of counterparty credit risks. By using the asymptotic expansion approach we can evaluate the price of various kinds of credit derivatives under the many specific and popular models, such as affine models and constant elasticity of variance models. © 2012, Incisive Media Ltd. All Rights Reserved. Source

Combretastatin can prevent the supply of nutrients to cancer cells by selectively interrupting tumor blood flow (TBF). Therefore, combretastatin may serve as a new anticancer drug that utilizes starvation tactics to attack solid tumors. Among combretastatin compounds, combretastatin A-4 and a combretastatin A-4 derivative (Cderiv) are now in phase III clinical trials. These two combretastatin compounds have similar chemical structures and provide marked TBF interruption. However, their mechanisms of action are reportedly quite different and remain controversial. Precise mechanisms of action of these agents must be elucidated so as to develop safe clinical treatments and wider clinical applications. By using various kinds of rodent tumors, we showed that Cderiv produced potent interruption of TBF in all primary tumors and metastatic foci, without exception, and had beneficial therapeutic effects including significantly improved survival. Cderiv caused host arterioles to constrict. However, a tumor vascular bed scarcely reacted to a direct topical application of Cderiv. In addition, the fact that Cderiv did not have cytotoxic drug-like accumulated toxicity usually caused by repeated administration means that inhibition of tubulin polymerization by Cderiv may not occur to a great degree in vivo. Therefore, at least for Cderiv, our studies demonstrated that TBF interruption was mainly caused indirectly, via enhancement of vascular resistance of host arterioles, rather than being caused by a direct effect of Cderiv on tumor vessels. In this review, I describe cancer therapy that utilizes such TBF interruption, which leads to Cderiv-induced necrosis, and discuss details of its microcirculation mechanism. Source

Jiao H.,Technical University of Delft | Bauer G.E.W.,Technical University of Delft | Bauer G.E.W.,Tohoku University
Physical Review Letters | Year: 2013

The spin current pumped by a precessing ferromagnet into an adjacent normal metal has a constant polarization component parallel to the precession axis and a rotating one normal to the magnetization. The former is now routinely detected as a dc voltage induced by the inverse spin Hall effect (ISHE). Here we compute ac ISHE voltages much larger than the dc signals for various material combinations and discuss optimal conditions to observe the effect. The backflow of spin is shown to be essential to distill parameters from measured ISHE voltages for both dc and ac configurations. © 2013 American Physical Society. Source

Chiba S.,Tohoku University
Conservation Biology | Year: 2010

The influence of non-native species on native ecosystems is not predicted easily when interspecific interactions are complex. Species removal can result in unexpected and undesired changes to other ecosystem components. I examined whether invasive non-native species may both harm and provide refugia for endangered native species. The invasive non-native plant Casuarina stricta has damaged the native flora and caused decline of the snail fauna on the Ogasawara Islands, Japan. On Anijima in 2006 and 2009, I examined endemic land snails in the genus Ogasawarana. I compared the density of live specimens and frequency of predation scars (from black rats [Rattus rattus]. ) on empty shells in native vegetation and Casuarina forests. The density of land snails was greater in native vegetation than in Casuarina forests in 2006. Nevertheless, radical declines in the density of land snails occurred in native vegetation since 2006 in association with increasing predation by black rats. In contrast, abundance of Ogasawarana did not decline in the Casuarina forest, where shells with predation scars from rats were rare. As a result, the density of snails was greater in the Casuarina forest than in native vegetation. Removal of Casuarina was associated with an increased proportion of shells with predation scars from rats and a decrease in the density of Ogasawarana. The thick and dense litter of Casuarina appears to provide refugia for native land snails by protecting them from predation by rats; thus, eradication of rats should precede eradication of Casuarina. Adaptive strategies, particularly those that consider the removal order of non-native species, are crucial to minimizing the unintended effects of eradication on native species. In addition, my results suggested that in some cases a given non-native species can be used to mitigate the impacts of other non-native species on native species. ©2010 Society for Conservation Biology. Source

Lee U.,Tohoku University
Monthly Notices of the Royal Astronomical Society | Year: 2010

We investigate non-axisymmetric low-frequency modes of a rotating and magnetized neutron star, assuming that the star is threaded by a dipole magnetic field whose strength at the stellar surface, B0, is less than G, and whose magnetic axis is aligned with the rotation axis. For modal analysis, we use a neutron star model composed of a fluid ocean, a solid crust and a fluid core, where we treat the core as being non-magnetic assuming that the magnetic pressure is much smaller than the gas pressure in the core. For non-axisymmetric modes, spheroidal modes and toroidal modes are coupled in the presence of a magnetic field even for a non-rotating star. Here, we are interested in low-frequency modes of a rotating and magnetized neutron star whose oscillation frequencies are similar to those of toroidal crust modes of low spherical harmonic degree and low radial order. For a magnetic field of G, we find Alfvén waves in the ocean have similar frequencies to the toroidal crust modes, and we find no r modes confined in the ocean for this strength of the field. We calculate the toroidal crustal modes, the interfacial modes peaking at the crust/core interface and the core inertial modes and r modes, and all these modes are found to be insensitive to the magnetic field of strength G. We find the displacement vector of the core r modes have large amplitudes around the rotation axis at the stellar surface even in the presence of a surface magnetic field G, where and m are the spherical harmonic degree and the azimuthal wavenumber of the r modes, respectively. We suggest that millisecond X-ray variations of accretion-powered X-ray millisecond pulsars can be used as a probe into the core r modes destabilized by gravitational wave radiation. If the r mode is excited, we will have the pulsation of the frequency with being the spin frequency of the star. © 2010 The Author. Journal compilation © 2010 RAS. Source

A method to measure CsI cluster ions ((CsI)nCs+, (CsI)nI-) from CsI samples in matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) was developed with a 2-[(2E)-3-(4-tert-butylphenyl)-2-methylprop-2-enylidene] malononitrile (DCTB) matrix and additives. Solvent combinations in which the CsI and DCTB solutions were miscible were effective in detecting CsI cluster ions at a mass range of over m/z 2000 and are associated with a characteristic spread of DCTB within the CsI/DCTB mixture. The addition of saccharides or sugar alcohols to the CsI/DCTB mixture improved the DCTB distribution and widened the mass distribution of CsI cluster ions up to m/z 10 000 in the linear mode. Copyright © 2014 John Wiley & Sons, Ltd. Copyright © 2014 John Wiley & Sons, Ltd. Source

Estili M.,Japan National Institute of Materials Science | Kawasaki A.,Tohoku University | Sakka Y.,Japan National Institute of Materials Science
Advanced Materials | Year: 2012

A highly concentrated 3D macrostructure of individual multiwalled carbon nanotubes (MWCNTs) is practically realized in a ceramic environment with poreless/intimate interfaces by a scalable aqueous colloidal approach. This concept dramatically improves not only the transport property and network connectivity of the MWCNT 3D macrostructures (a DC-conductivity of nearly 5000 S m-1) but also the strain tolerance of the ceramic environment. Such low-cost and novel MWCNT/ceramic hybrids have many potential functional and structural applications. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Miyaoka R.,Tohoku University
Differential Geometry and its Application | Year: 2013

We extend theorems of É. Cartan, Nomizu, Münzner, Q.M. Wang, and Ge-Tang on isoparametric functions to transnormal functions on a general Riemannian manifold. We show that if a complete Riemannian manifold M admits a transnormal function, then M is diffeomorphic to either a vector bundle over a submanifold, or a union of two disk bundles over two submanifolds. Moreover, a singular level set Q is austere and minimal, if exists, and generic level sets are tubes over Q. We give a criterion for a transnormal function to be an isoparametric function. © 2012 Elsevier B.V. Source

Gleadall I.G.,Tohoku University
Journal of Experimental Marine Biology and Ecology | Year: 2013

Trials were performed with magnesium chloride, ethanol and eight more complex organic substances screened for their effect as immersion anaesthetics for small, medium and large octopus species commonly used as experimental animals in Japan: Amphioctopus fangsiao, Octopus vulgaris, and Enteroctopus dofleini, respectively. Four of the organics were synthetic compounds commonly used as fish anaesthetics (metomidate, MS-222, propoxate, and quinaldine sulphate) and four have been used on other invertebrates (chloretone, gallamine, phenoxetol, and nicotine sulphate). Urethane (no longer used because of its carcinogenic properties) was used as a reference anaesthetic because of its long history of success with octopuses. Best results for anaesthetic effect were obtained with magnesium chloride and ethanol (which mimicked the typical anaesthetic effects seen with urethane) although some resistance to full anaesthesia was observed with ethanol when water temperatures were 10. °C or below in winter. No successful anaesthetic effects were obtained with the fish anaesthetics: in particular, metomidate was toxic even at low concentrations. Similarly (at the temperatures tested), chloretone, nicotine sulphate and phenoxetol were ineffective as anaesthetics and had toxic effects. Substances used to date as anaesthetics for cephalopods are briefly reviewed and it is concluded that future investigations to improve the provision of stable, safe and reliable anaesthesia for cephalopods would probably benefit from combinations of higher doses for shorter exposure times, and the co-administration of two or more substances. Empirical testing is still required for application to different species and to define appropriate concentrations, temperature and pH ranges. © 2013 Elsevier B.V. Source

Gleadall I.G.,Tohoku University
Journal of Experimental Marine Biology and Ecology | Year: 2013

Long-term sedation tests (>3days, continuous) were conducted with millimolar quantities of magnesium sulphate to enhance the condition and survival of firefly squid, Watasenia scintillans, during commercial transportation. A concentration of 20mmoll-1 produced the best result. After more than 80h under constant sedation, the animals revived within minutes of being transferred to fresh seawater and were apparently unharmed. © 2013 Elsevier B.V. Source

Kokubun M.,Tohoku University
Field Crops Research | Year: 2013

Soybean (Glycine max (L.) Merr.) is vulnerable to waterlogging, which threatens soybean productivity in humid regions of Asia. Waterlogging can happen during any growth stage of soybean, but flooding stress before, at or after germination causes severe seed and seedling damage, resulting in substantial reduction of grain yield at maturity. Under waterlogged conditions, seeds imbibe rapidly, destroying seed tissues due to abrupt swelling of the cells. Anatomical observations during water absorption of seeds revealed that the aleurone layer blocks abrupt water penetration into the embryo regardless of genotype. Based on these observations, genetic analyses of waterlogging-tolerant genotypes are currently in progress and attempts to incorporate the genes responsible for such tolerance are being made. Among cultural measures to alleviate waterlogging-induced damage during germination, pre-hydrating seeds prior to sowing proved to be most effective. After emergence, waterlogging impairs root function, primarily due to hypoxia, and thereby the capacity for nutrient uptake and growth. Molecular characterization of enzymes expressed in growing plants subjected to waterlogging treatment has identified several genes involved in anaerobic respiration. In addition, some soybean cultivars were found to form aerenchyma, which transports oxygen from aboveground tissues to the root system, in response to waterlogging. These phenomena should be exploited for breeding waterlogging-tolerant cultivars. Cultural methods including partial tillage and adjustment of the water table also effectively mitigate damage caused by waterlogging. Integration of these approaches should lead to stable soybean production in humid agricultural areas of Asia. © 2012 Elsevier B.V. Source

Kurata S.,Tohoku University
Developmental and Comparative Immunology | Year: 2014

Innate immunity is the front line of self-defense against infectious non-self in vertebrates and invertebrates. The innate immune system is mediated by germ-line encoding pattern recognition molecules (pathogen sensors) that recognize conserved molecular patterns present in the pathogens but absent in the host. Peptidoglycans (PGN) are essential cell wall components of almost all bacteria, except mycoplasma lacking a cell wall, which provides the host immune system an advantage for detecting invading bacteria. Several families of pattern recognition molecules that detect PGN and PGN-derived compounds have been indentified, and the role of PGRP family members in host defense is relatively well-characterized in Drosophila. This review focuses on the role of PGRP family members in the recognition of invading bacteria and the activation and modulation of immune responses in Drosophila. © 2013 Elsevier Ltd. Source

Background: Despite low gastric acid secretion levels among elderly people and Helicobacter pylori-positive individuals in Japan, many patients suffer from endoscopic relapse of erosive gastroesophageal reflux disease (GERD) during standard-dose proton pump inhibitor (PPI) maintenance therapy. We aimed to investigate the relapse rate and risk factors for relapse during long-term PPI therapy in a prospective multicenter study. Methods: Patients diagnosed endoscopically as having erosive GERD according to the Los Angeles (LA) classification, with remission under PPI medication, and without mucosal damage in the esophagus, were enrolled and took rabeprazole 10 mg/day, the standard dose in Japan, for up to 104 weeks, with endoscopy at weeks 24, 52, 76, and 104; erosive GERD with LA classification grade A, B, C, or D was defined as relapse. Results: The baseline status of the 191 cases analyzed was: female (34.6%), ≥65 years old (50.8%), H. pylori-positive (40.8%), body mass index (BMI) ≥25 kg/m 2 (35.6%), and hiatus hernia (79.6%). Relapse occurred by week 104 in 21 cases (11%; 12 females, 9 males). Risk factors were hiatus hernia; severe past erosive GERD (grade C or D); H. pylori-negative; no mucosal atrophy; nonsmoking; and being female and <150 cm in height. Conclusions: This study revealed the significant risk factors that might be monitored during long-term maintenance therapy to prevent relapse of GERD. © 2010 Springer. Source

In the gastrointestinal mucosal immune system, T-lymphocytes are activated to produce pro-inflammatory cytokines, and the over-activation of the lymphocytes is primarily responsible for the development of inflammatory bowel disease (IBD). Despite our understanding of the molecular involvement in the activation of lymphocytes, we know little about the physiological involvement. Circulating T-lymphocytes or those derived from thymus predominantly express delayed rectifier K+-channels (Kv1.3) in their plasma membranes and these channels play crucial roles in inducing the lymphocyte activation and proliferation. In the pathogenesis of chronic renal failure, these channels, which are overexpressed in proliferating lymphocytes within the kidneys, are responsible for the progression of the disease. Since the over-activation of cellular immunity is also involved in the pathogenesis of IBD, T-lymphocytes in the gastrointestinal mucosa could share the same stimulatory mechanisms with those in the inflamed kidneys. Therefore, we hypothesize here that T-lymphocytes in the gastrointestinal mucosa would also be stimulated by the activation of the Kv1.3-channels expressed in their plasma membranes, and that the overexpression of the channels would contribute to the development of IBD. Our hypothesis is unique because it sheds light for the first time on a physiological mechanism by which T-lymphocytes are activated in the gut mucosal immune system. It is also important because our idea could have novel therapeutic implications for IBD, in which the over-activation of the lymphocytes is responsible for the pathogenesis. © 2015 Elsevier Ltd. Source

Sekine A.,Tohoku University
Physical Review B - Condensed Matter and Materials Physics | Year: 2016

We perform a theoretical search for dynamical cross-correlated responses of three-dimensional topological superconductors and superfluids. It has been suggested that a gravitational topological term, which is analogous to the θ term in topological insulators, can be derived in three-dimensional time-reversal invariant topological superconductors and superfluids, and that the dynamical gravitational axion field can be realized by the fluctuation of the relative phase, i.e., by the Leggett mode between topological p-wave pairing and conventional s-wave pairing. In the presence of the dynamical gravitational axion field, we propose the emergence of the "chiral gravitomagnetic effect," a thermal current generation by gravitomagnetic fields, i.e., by mechanical rotations. This effect can be regarded as a thermal counterpart of the chiral magnetic effect, which has been studied mainly in Weyl semimetals. We also show the occurrence of the anomalous thermal Hall effect in the bulk. We discuss a possible application of our study to the thermal responses of Weyl superconductors. © 2016 American Physical Society. Source

Hongo M.,Tohoku University | Fujimoto K.,Saga Medical School
Journal of Gastroenterology | Year: 2010

Goal To investigate the development of fundic gland polyp (FGP) and gastric hyperplastic polyp (HPP) during long-term proton pump inhibitor (PPI) therapy and risk factors of each polyp via patient status in a multicenter prospective study. Background The risk of developing FGP may increase during long-term PPI therapy. However, the association with PPI-induced hypergastrinemia is unclear. Helicobacter pylori (Hp) infection (which there is a high rate of in Japan) may influence the development of HPP. Methods Reflux esophagitis patients on PPI maintenance therapy were enrolled. At baseline, the presence of protruding lesion (gastric polyps) and mucosal atrophy was examined endoscopically. The serum gastrin level (SGL) and Hp infection status were noted. The patients took rabeprazole 10 mg/day for 104 weeks and endoscopy was performed at weeks 24, 52, 76, and 104 to check for newly developed FGPs and HPPs. The hazard ratios (HRs) of risk factors were calculated. Results 191 patients were analyzed. The distribution of patients with baseline SGLs (pg/mL) of <200, ≥200 to <400, and ≥400 was 118 (61.8%), 51 (26.7%), and 22 (11.5%), respectively. 78 (40.8%) patients were Hp-positive, and gastric polyps were found in 70 (36.6%) patients. By the end of rabeprazole therapy, 26 (13.6%) and 17 (8.9%) patients had developed new FGPs and HPPs. In terms of risk factors, Hp-positive was significantly lower (HR = 0.288; 95% CI, 0.108-0.764) for FGP while SGL ≥400 pg/mL was significantly higher (HR = 4.923; 95% CI, 1.486-16.31) for HPP. Conclusion During long-term PPI therapy, FGP development was associated with absence of Hp infection. Meanwhile, Hp infection and high SGL may influence HPP development. © Springer 2010. Source

Spin–orbit torque (SOT)-induced magnetization switching shows promise for realizing ultrafast and reliable spintronics devices. Bipolar switching of the perpendicular magnetization by the SOT is achieved under an in-plane magnetic field collinear with an applied current. Typical structures studied so far comprise a nonmagnet/ferromagnet (NM/FM) bilayer, where the spin Hall effect in the NM is responsible for the switching. Here we show that an antiferromagnet/ferromagnet (AFM/FM) bilayer system also exhibits a SOT large enough to switch the magnetization of the FM. In this material system, thanks to the exchange bias of the AFM, we observe the switching in the absence of an applied field by using an antiferromagnetic PtMn and ferromagnetic Co/Ni multilayer with a perpendicular easy axis. Furthermore, tailoring the stack achieves a memristor-like behaviour where a portion of the reversed magnetization can be controlled in an analogue manner. The AFM/FM system is thus a promising building block for SOT devices as well as providing an attractive pathway towards neuromorphic computing. © 2016 Nature Publishing Group Source

Watanabe A.,Tohoku University
Journal of Photopolymer Science and Technology | Year: 2013

Laser sintering of Au nanoparticles on a Cu substrate was studied toward an alterna-tive to gold plating. The laser sintering by laser direct writing method required much higher laser power density in comparison with that on a glass substrate. The la-ser-induced heat accumulation method is proposed as a new laser sintering method which can be applied to a metal substrate with a high thermal diffusion coefficient such as a Cu substrate. In the sintering process, the dissipation through the Cu with a high thermal diffusion coefficient was reduced by using a thermally isolated Cu substrate, where the heat accumulation in the Cu micropattern was caused sintering of whole area by laser pulse irradiation at a small spot without laser beam scanning. The SIMS profile showed that the diffusion of the Cu atom through the gold layer was reduced remarkably by the laser sintering compared to the conventional heat treatment. The reduction of Cu diffusion into gold layer is due to the extremely short sintering time of the laser-induced heat accumulation method. © 2013SPST. Source

Takahashi M.,Tohoku University
Crystals | Year: 2014

The development of terahertz technology in the last few decades has made it possible to obtain a clear terahertz (THz) spectrum. THz vibrations clearly show the formation of weak bonds in crystals. The simultaneous progress in the code of first-principles calculations treating noncovalent interactions has established the position of THz spectroscopy as a powerful tool for detecting the weak bonding in crystals. In this review, we are going to introduce, briefly, the contribution of weak bonds in the construction of molecular crystals first, and then, we will review THz spectroscopy as a powerful tool for detecting the formation of weak bonds and will show the significant contribution of advanced computational codes in treating noncovalent interactions. From the second section, following the Introduction, to the seventh section, before the conclusions, we describe: (1) the crystal packing forces, the hydrogen-bonded networks and their contribution to the construction of organic crystals; (2) the THz vibrations observed in hydrogen-bonded molecules; (3) the computational methods for analyzing the THz vibrations of hydrogen-bonded molecules; (4) the dispersion correction and anharmonicity incorporated into the first-principles calculations and their effect on the peak assignment of the THz spectrum (5) the temperature dependence; and (6) the polarization dependence of the THz spectrum. © 2011 by the authors; licensee MDPI, Basel, Switzerland. Source

Jupesta J.,Tohoku University
Applied Energy | Year: 2012

In Indonesia, the high subsidy on fossil fuel significantly burdens the country's economy. The partial replacement of fossil fuel by biofuel in the transportation sector would significantly reduce fossil oil consumption. To enable this replacement, a model was built to predict the effects of biofuel in the energy system. This paper examines the importance of technological changes in biofuel production. The objective is to find the optimal net energy balance under land and technology constraints. An optimization model to find this optimum was developed by using GAMS as a tool to provide the optimal answer about the potential of biofuel production in Indonesia in a scenario of technology development and a base scenario. The model shows that a net energy balance can be achieved with up to 3.8. kPJ in the technology scenario and 0.9. kPJ in the base scenario (a scenario describing present government policy). The export value could rise to 33 billion US$ in the technology scenario. In the base scenario, the export value of biofuel drops from 7 billion US$ in 2023 and further declines thereafter due to the low growth in land allocation whilst domestic demand is increasing. The lowest production cost is achieved with palm oil production at 9.5 US$/GJ in 2025. The net emission balance in the base scenario could achieve 54. Mtce, while in the technology scenario it could achieve 212. Mtce. The technology scenario relies on technological changes through R&D and economies of scale, which are not considered in the base scenario. The outcome of the model is that technological changes could have a positive impact on the introduction of biofuel in the transportation sector in Indonesia, i.e.: a higher net energy balance, higher export value, lower production cost and higher net emission balance. © 2011 Elsevier Ltd. Source

Targeting cell motility, which is required for dissemination and metastasis, has therapeutic potential for ovarian cancer metastasis, and regulatory mechanisms of cell motility need to be uncovered for developing novel therapeutics. Invasive ovarian cancer cells spontaneously formed protrusions, such as lamellipodia, which are required for generating locomotive force in cell motility. Short interfering RNA screening identified class II phosphatidylinositol 3-kinase C2β (PI3KC2β) as the predominant isoform of PI3K involved in lamellipodia formation of ovarian cancer cells. The bioactive sphingolipid ceramide has emerged as an antitumorigenic lipid, and treatment with short-chain C6-ceramide decreased the number of ovarian cancer cells with PI3KC2β-driven lamellipodia. Pharmacological analysis demonstrated that long-chain ceramide regenerated from C6-ceramide through the salvage/recycling pathway, at least in part, mediated the action of C6-ceramide. Mechanistically, ceramide was revealed to interact with the PIK-catalytic domain of PI3KC2β and affect its compartmentalization, thereby suppressing PI3KC2β activation and its driven cell motility. Ceramide treatment also suppressed cell motility promoted by epithelial growth factor, which is a prometastatic factor. To examine the role of ceramide in ovarian cancer metastasis, ceramide liposomes were employed and confirmed to suppress cell motility in vitro. Ceramide liposomes had an inhibitory effect on peritoneal metastasis in a murine xenograft model of human ovarian cancer. Metastasis of PI3KC2β knocked-down cells was insensitive to treatment with ceramide liposomes, suggesting specific involvement of ceramide interaction with PI3KC2β in metastasis suppression. Our study identified ceramide as a bioactive lipid that limits PI3KC2β-governed cell motility, and ceramide is proposed to serve as a metastasis-suppressor lipid in ovarian cancer. These findings could be translated into developing ceramide-based therapy for metastatic diseases.Oncogene advance online publication, 14 September 2015; doi:10.1038/onc.2015.330. © 2015 Macmillan Publishers Limited Source

Yoshikawa N.,Tohoku University
Journal of Microwave Power and Electromagnetic Energy | Year: 2010

As the fundamentals of microwave (MW) interaction with metals, boundary conditions of electromagnetic (EM) field on metal surface are discussed, which consider the EM field in the metal surface layer in terms of surface impedance. Experimental report on heating behavior of separated electric (E-) and magnetic (H-) fields of metal particles and films are shown. Temperature peak formation at the first heating curves was observed in both cases, which are discussed considering the microstructural alteration by MW heating. In the last half section, various reports on MW heating of metal are reviewed. They were classified into the major application for sintering and materials fabrication. And also, its usage as a heating aid of glasses and soils, topics on metal hydride and catalytic metal particles are included. Source

Rikiishi H.,Tohoku University
Journal of Biomedicine and Biotechnology | Year: 2011

Because epigenetic alterations are believed to be involved in the repression of tumor suppressor genes and the promotion of tumorigenesis in cancers, novel compounds endowed with histone deacetylase (HDAC) inhibitory activity are an attractive therapeutic approach. Indeed, the potential of HDAC inhibitors for cancer therapy has been explored in preclinical models, and some agents approved for hematologic malignancies have reached the clinical setting. HDAC inhibitors are able to mediate the induction of both apoptosis and autophagy, which are related to anticancer activity in a variety of cancer cell lines. Given the inherent resistance to apoptosis that characterizes cancer, the targeting of alternative pathways is an attractive strategy to improve anti-tumor therapy. The activation of autophagy represents novel cancer treatment targets. This paper aims to critically discuss how the anticancer potential of HDAC inhibitors may elicit a response to human cancers through different cell pathways leading to cell death. Copyright 2011 Hidemi Rikiishi. Source

Louzguine-Luzgin D.V.,Tohoku University
Journal of Alloys and Compounds | Year: 2014

The crystallization kinetics and structural changes of a few metallic glassy alloys were monitored using X-ray diffraction, transmission electron microscopy, differential scanning and isothermal calorimetry methods. Microstructural observations were used to estimate the nucleation and growth rates. A clear comparison of the differences in the crystallization kinetics in the metallic glassy samples is observed at the early and later crystallization stages.© 2013 Elsevier B.V. All rights reserved. Source

Tsuiji K.,Tohoku University
The Tohoku journal of experimental medicine | Year: 2010

Uterine leiomyomas are the most common gynecological benign tumor and greatly affect reproductive health and wellbeing, but the pathophysiology and epidemiology of uterine leiomyoma are poorly understood. One of the major reasons for the slow progress in leiomyoma research is the lack of a good in vivo model system. We therefore aimed to develop a novel model by transplanting human uterine leiomyoma xenografts in an immunodeficient mouse strain (NOD/SCID/gammac-null: NOG). Human uterine leiomyoma tissues were cut into small pieces and inserted subcutaneously into the right and left flanks of NOG mice. Estrogen supplementation was needed to maintain the features of uterine leiomyoma in xenografted tissues. After 4 weeks or 8 weeks of transplantation, xenografted tissues were harvested and analyzed regarding tissue morphology, collagen content, and proliferation and apoptosis of uterine leiomyoma smooth muscle cells. The xenografts that were harvested after 4 weeks and 8 weeks retained the histological architecture of original uterine leiomyoma tissue both in cellular and collagen components. The expression profiles of key markers of uterine leiomyoma were also maintained, including estrogen receptor, progesterone receptor, and alpha-smooth muscle actin, as judged by immunohistochemical staining. The proportion of proliferating cells was significantly increased (1.5-fold) in the xenografts after 8 weeks of transplantation, whereas that of the apoptotic cells remained unchanged. Importantly, the reproducible results were obtained with the tumor tissues derived from six patients. The present in vivo model may provide a useful tool for development of novel therapeutic strategies for uterine leiomyoma. Source

Tohmyoh H.,Tohoku University
Applied Physics Letters | Year: 2013

A heat conduction model for determining the temperature of a nanowire through which a current is passed is proposed. In the model, the total Joule heating arising in the nanowire due to the current is considered until the system reaches a steady state. It is important to determine the positions of the "cold points" in the system, where the temperature is left unchanged by the current. The current required to cut a nanowire is predicted from the model. The mechanism for Joule heat welding is classified depending on the positions of the cold points in the metallic nanowire system. © 2013 American Institute of Physics. Source

T lymphocytes predominantly express delayed rectifier K+ channels (Kv1.3) in their plasma membranes. More than 30 years ago, patch-clamp studies revealed that the channels play crucial roles in facilitating the calcium influx necessary to trigger lymphocyte activation and proliferation. In addition to selective channel inhibitors that have been developed, we recently showed physiological evidence that drugs such as nonsteroidal anti-inflammatory drugs, antibiotics, and anti-hypertensives effectively suppress the channel currents in lymphocytes, and thus exert immunosuppressive effects. Using experimental animal models, previous studies revealed the pathological relevance between the expression of ion channels and the progression of renal diseases. As an extension, we recently demonstrated that the overexpression of lymphocyte Kv1.3 channels contributed to the progression of chronic kidney disease (CKD) by promoting cellular proliferation and interstitial fibrosis. Together with our in-vitro results, the studies indicated the therapeutic potency of Kv1.3-channel inhibitors in the treatment or the prevention of CKD. © 2014, The Physiological Society of Japan and Springer Japan. Source

Harada R.,Tohoku University
European journal of nuclear medicine and molecular imaging | Year: 2013

Extensive deposition of senile plaques and neurofibrillary tangles in the brain is a pathological hallmark of Alzheimer's disease (AD). Although several PET imaging agents have been developed for in vivo detection of senile plaques, no PET probe is currently available for selective detection of neurofibrillary tangles in the living human brain. Recently, [(18)F]THK-523 was developed as a potential in vivo imaging probe for tau pathology. The purpose of this study was to compare the binding properties of [(18)F]THK-523 and other amyloid imaging agents, including PiB, BF-227 and FDDNP, to synthetic protein fibrils and human brain tissue. In vitro radioligand binding assays were conducted using synthetic amyloid β(42) and K18ΔK280-tau fibrils. Nonspecific binding was determined by the addition of unlabelled compounds at a concentration of 2 μM. To examine radioligand binding to neuropathological lesions, in vitro autoradiography was conducted using sections of AD brain. [(18)F]THK-523 showed higher affinity for tau fibrils than for Aβ fibrils, whereas the other probes showed a higher affinity for Aβ fibrils. The autoradiographic analysis indicated that [(18)F]THK-523 accumulated in the regions containing a high density of tau protein deposits. Conversely, PiB and BF-227 accumulated in the regions containing a high density of Aβ plaques. These findings suggest that the unique binding profile of [(18)F]THK-523 can be used to identify tau deposits in AD brain. Source

Koshino M.,Tohoku University | McCann E.,Lancaster University
Physical Review B - Condensed Matter and Materials Physics | Year: 2013

We study the electronic structure of multilayer graphenes with a mixture of Bernal and rhombohedral stacking and propose a general scheme to understand the electronic band structure of an arbitrary configuration. The system can be viewed as a series of finite Bernal graphite sections connected by stacking faults. We find that the low-energy eigenstates are mostly localized in each Bernal section, and, thus, the whole spectrum is well approximated by a collection of the spectra of independent sections. The energy spectrum is categorized into linear, quadratic, and cubic bands corresponding to specific eigenstates of Bernal sections. The ensemble-averaged spectrum exhibits a number of characteristic discrete structures originating from finite Bernal sections or their combinations likely to appear in a random configuration. In the low-energy region, in particular, the spectrum is dominated by frequently appearing linear bands and quadratic bands with special band velocities or curvatures. In the higher-energy region, band edges frequently appear at some particular energies, giving optical absorption edges at the corresponding characteristic photon frequencies. © 2013 American Physical Society. Source

The retrieval of Green's function of scalar waves for a given medium is possible from the cross-correlation function (CCF) of noises in the equi-partition state. For making such a state, there are two typical ways to illuminate receivers: one is an illumination by noise sources randomly distributed on a surrounding spherical shell with large radius compared with the receiver separation; another is an illumination by the randomly homogeneous distribution of noise sources. In both cases, the wave velocity can be well evaluated from the peak lag time of the noise CCF. Furthermore, it is interesting whether Green's function having coda in a scattering medium is retrieved from the noise CCF. We proved Green's function retrieval for the former case in a previous work. Here, using the first-order Born approximation, we mathematically shows the retrieval of Green's function having coda in a scattering medium with small dissipation from the noise CCF for the latter case. A model for the scattering medium is mathematically given by a distribution of velocity anomalies represented by delta functions. Using the prolate spheroidal coordinates for the integration over the distributed noise sources, we prove that the derivative of CCF with respect to lag time is proportional to the convolution of the noise source auto-correlation function and antisymmetrized Green's function that has a coda tail caused by single scattering and an exponential decay term caused by dissipation. We note that Green's function retrieval is possible for this type of noise distribution even though the time reversal symmetry and energy conservation are broken. © 2009 The Author Journal compilation © 2009 RAS. Source

Suzuki A.,Tohoku University
Physics and Chemistry of Minerals | Year: 2010

An in situ synchrotron X-ray diffraction study was carried out on ε-FeOOH at room temperature up to a pressure of 8.6 GPa using the energy-dispersive method. The linear compressibility was determined to be βa = 1.69(3) × 10-3 GPa-1, βb = 2.86(6) × 10-3 GPa-1, and βc = 1.73(5) × 10-3 GPa-1. The b-axis of the unit cell is more compressible than the a and c axes. The pressure-volume data were fitted to a third-order Birch-Murnaghan equation of state. The best fit was found using a room temperature isothermal bulk modulus of K0 = 126(3) GPa and its pressure derivative K′ = 10(1). © Springer-Verlag 2009. Source

Nomura D.,Tohoku University | Teubner T.,University of Liverpool
Nuclear Physics B | Year: 2013

Motivated by recent progress of theory and experiment on the anomalous magnetic moment of the electron, a e, we update the hadronic contributions to a e. Using our up-to-date compilation of e +e -→hadrons data, we find the leading order hadronic contribution aehad,LO,VP=(1.866±0.010exp±0.005rad){dot operator}10-12 and the next-to-leading order hadronic contribution aehad,NLO,VP=(-0.2234±0.0012exp±0.0007rad){dot operator}10-12, where the first and second errors are from the error of the experimental data and the uncertainty in the treatment of radiative corrections, respectively. These values are compatible with earlier evaluations by other groups, but have significantly improved uncertainties due to the more precise input data used. We also update the leading order hadronic contribution to the ground state hyperfine splitting of muonium, obtaining δνMuhad,VP=(232.68±1.25exp±0.72rad) Hz. This value is consistent with the most precise evaluation in the literature and reduces its error by a factor of two. © 2012 Elsevier B.V. Source

Nakayama K.,University of Tokyo | Takahashi F.,Tohoku University | Takahashi F.,University of Tokyo | Yanagida T.T.,University of Tokyo
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2013

We propose a chaotic inflation model in supergravity based on polynomial interactions of the inflaton. Specifically we study the chaotic inflation model with quadratic, cubic and quartic couplings in the scalar potential and show that the predicted scalar spectral index and tensor-to-scalar ratio can lie within the 1. σ region allowed by the Planck results. © 2013 Elsevier B.V. Source

Takahashi F.,Tohoku University
Journal of Cosmology and Astroparticle Physics | Year: 2013

We show that a sizable running spectral index suggested by the recent SPT data can be explained in the axionic curvaton model with a potential that consists of two sinusoidal contributions of different height and period. We find that the running spectral index is generically given by dns/d ln k ∼ 2π/ΔN (ns - 1)) where ΔN is the e-folds during one period of modulations. In the string axiverse, axions naturally acquire a mass from multiple contributions, and one of the axions may be responsible for the density perturbations with a sizable running spectral index via the curvaton mechanism. We note that the axionic curvaton model with modulations can also accommodate the red-tilted spectrum with a negligible running, without relying on large-field inflation. © 2013 IOP Publishing Ltd and Sissa Medialab srl. Source

Nakamura S.N.,Tohoku University
Nuclear Physics A | Year: 2013

Professor Osamu Hashimoto of Tohoku University passed away on February 3, 2012. As well as leading the nuclear physics laboratory of Tohoku University, Prof. Hashimoto contributed much to hypernuclear and strangeness nuclear physics community for years. In this decade, he devoted himself to establish the (e, e 'K +) hypernuclear spectroscopy. I will review progresses of Λ hypernuclear spectroscopy with a memory of this decade which I was privileged to share with Prof. Hashimoto. © 2013 Elsevier B.V. Source

Nakabayashi K.,Kanazawa University | Miyasaka H.,Tohoku University
Chemistry - A European Journal | Year: 2014

The temperature-induced stepwise neutral-ionic (N-I) phase transition in the covalently bonded donor-acceptor chain compound [Ru2(2,3,5,6- F4PhCO2)4DMDCNQI]̇ 2(p-xylene) (2,3,5,6-F4PhCO2-=2,3,5,6-tetrafluorobenzoate; DMDCNQI=2,5-dimethyl-N,N′-dicyanoquinodiimine) was systematically tuned over a wide temperature range using two techniques: 1) A chemical technique based on doping with a less-active donor unit [Ru2 II,II(F5PhCO2)4] (F 5PhCO2-=pentafluorobenzoate), thereby providing an isostructural doped series [{Ru2II,II(2,3,5,6-F 4PhCO2)4}1-x{Ru2 II,II(F5PhCO2)4}xDMDCNQI] ̇2(p-xylene), with x=0.06, 0.10, 0.21, and 0.24; and 2) a physical technique, which was the application of hydrostatic pressure to the doped compounds. The stepwise N-I transition observed in the original compound was systematically varied in terms of the viewpoints of both transition temperature and transition features (stepwise or monotonic) dependent on the amount of dopants x. Application of pressure efficiently tuned the N-I transitions, with the oxidation phases being dramatically modified by applying only weak pressure up to 4 kbar. Even in cases that led to N-I transitions in small domains of the chains at ambient pressure, the application of pressure caused an expansion of the domains that enabled N-I transitions, finally leading to a complete change in the oxidation state of the chains, from neutral to ionic, accompanied by a change from a paramagnetic state to a ferrimagnetically ordered state. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

When non-metallic atoms are excited in a low-pressure glow discharge plasma, absorption transitions can be observed in the 640-930 nm wavelength range where laser diodes are commercially available. These excited atoms can be sensitively probed by diode laser atomic absorption spectrometry (DL-AAS). Because an atomic absorption transition can also be detected by coherent forward scattering (CFS) spectrometry and CFS spectrometry with a diode laser has more attractive features than DL-AAS, diode laser coherent forward scattering spectrometry (DL-CFS) was employed to investigated the absorption transition of excited argon atom at 842.46 nm. Ar (I) 842.46 nm line was adopted due to the tunable wavelength range of available diode laser in this experiment. Excited argon atoms were produced in a glow discharge plasma. CFS signal intensity at 842.46 nm attained maximum at discharge current of 20 mA in 3 Torr (399 Pa) of argon and at magnetic field of 160 mT. Calibration curve of argon was prepared to mix a small amount of argon into 6 Torr (798 Pa) of helium. The signal intensity depended on the 4.4th power of the number density of argon. The 4.4th power dependence is too large to be explained by the theoretically predicted quadratic dependence. When a small amount of molecular nitrogen was mixed into argon plasma, strong suppression of CFS intensity was observed. Molecular gases such as air were found to be unsuitable for the plasma gas to excite the target atoms. © 2015 ISIJ. Source

Fukushima K.,Tohoku University
The Tohoku journal of experimental medicine | Year: 2011

Organ allocation in Japan remains difficult due to the shortage of deceased-donor livers. The screening tool for controlling nutritional status (CONUT) has been considered to be an established assessment model for evaluating nutritional aspects in surgical patients. However, the application of this CONUT for evaluating the prognosis of patients with end-stage liver diseases has not been evaluated. We assessed the predictability of the prognoses of 58 patients with end-stage liver disease using various prognostic models. The patients registered at the transplantation center of Tohoku University Hospital for the waiting list of Japan Organ Transplant Network for liver transplantation were retrospectively analyzed. The prognoses of the patients were evaluated using the following 5 models: CONUT, the model for ELD with incorporation of sodium (MELD-Na), Child-Turcotte-Pugh score (CTP), prognostic nutritional indices (Onodera: PNI-O), and the Japan Medical Urgency criteria of the liver (JMU). Cox's proportional hazard model, log-rank test and concordance(c)-static were used for the statistics. The indices were 17.74 ± 5.80 for MELD-Na, 9.21 ± 2.19 for CTP, 33.92 ± 11.16 for PNI-O, and 7.57 ± 3.09 for CONUT. Univariate analysis revealed the significance of CONUT (p = 0.017, Odds: 1.325) but not MELD-Na, CTP, JMU or PNI-O for prediction. The cumulative survival rate was clearly discriminated at CONUT point 7. The c-static was 0.081 for the 6-month (M) survival rate, 0.172 for 12M, 0.517 for 36M, 0.821 for 48M, and 0.938 for 60M for CONUT. In conclusion, CONUT shows best predictability for the distant prognoses of patients with ELD. Source

Sitagliptin, a dipeptidyl peptidase-4 (DPP-4) inhibitor, is a newly developed oral hypoglycemic agent. Sitagliptin increases the level of glucagon-like polypeptide (GLP)-1 that increases insulin secretion. In addition, GLP-1 decreases salt intake and increases urinary salt excretion. Therefore, the sitagliptin treatment might lower blood pressure in hypertensive patients with type 2 diabetes. It also remains to be examined whether the reduction in blood pressure with sitagliptin treatment is related to the blood glucose improvement and the body weight decrease. To identify beneficial effects of sitagliptin treatment, we administered sitagliptin (50 mg) on alternate days to seventeen type 2 diabetes outpatients with insufficient blood glucose control (8 males and 9 females; mean age of 67.1 years). The patients were also treated with oral hypoglycemic agents and antihypertensive drugs for six months before and during the sitagliptin administration. We measured the level of hemoglobin (Hb) A1c, systolic blood pressure (SBP), and body mass index (BMI) for up to six months thereafter. Their BMIs remained unchanged. The levels of HbA1c were dropped from 6.5 ± 0.3% to 5.8 ± 0.3%, while SBP was also dropped from 130.0 ± 37.2 mmHg to 119.7 ± 9.4 mmHg. However, the degree of the decrease in HbA1c levels was not significantly correlated with that of SBP (r = 0.24). In conclusion, the present findings suggest that sitagliptin lowers SBP without reducing BMI, independent of the blood glucose reduction. The hypotensive effect is apparent with the alternate-day regimen of sitagliptin at a lower dose compared to the everyday medication. Source

Hozawa A.,Tohoku University
Clinical and experimental hypertension (New York, N.Y. : 1993) | Year: 2011

Previous studies have suggested that outside temperature affects blood pressure (BP) levels. However, recently, due to a spreading heating system, the seasonal variation in BP levels might be smaller, especially in colder seasons when more heat is used. We used continuous measurements of home BP data to track seasonal variations of BP to analyze the relation between outside temperature and BP values. Among 213 volunteers who were asked to measure BP in September 2000, 79 participants (mean age 72.7 years, 60.0% women) measured BP at least once per month until August 2003 (36 months). The mean number of measurements was 19.0 times/month. Information on outside temperature was provided by the Japan Meteorological Agency. We used general linear models to analyze the relation between outside temperature and BP values. Blood pressure levels were lowest in the warmest months. However, the highest BP levels were not observed in the coldest month, but rather in March. A clear inverse association between temperature and BP values was evident only in periods when outside temperatures were above 10°C. When the outside temperature was ≥ 10°C, 1°C increment of outside temperature correspond to 0.40 and 0.28 mmHg decrease of systolic blood pressure (SBP) and diastolic blood pressure (DBP), whereas the corresponding values were 0.06 and 0.01 mmHg when the outside temperature was <10°C. In conclusion, inverse association between outside temperature and BP was observed only in warmer seasons. Source

Maeta S.,Tohoku University
Journal of Geometry and Physics | Year: 2012

We consider a complete nonnegative biminimal submanifold M (that is, a complete biminimal submanifold with λ ≥ 0) in a Euclidean space EN. Assume that the immersion is proper, that is, the preimage of every compact set in EN is also compact in M. Then, we prove that M is minimal. From this result, we give an affirmative partial answer to Chen's conjecture. For the case of λ < 0, we construct examples of biminimal submanifolds and curves. © 2012 Elsevier B.V.. Source

Honda N.,Tohoku University
Communications in Mathematical Physics | Year: 2013

In this article we investigate deformations of a scalar-flat Kähler metric on the total space of complex line bundles over ℂℙ1 constructed by C. LeBrun. In particular, we find that the metric is included in a one-dimensional family of such metrics on the four-manifold, where the complex structure in the deformation is not the standard one. © 2013 Springer-Verlag Berlin Heidelberg. Source

Cho H.,Tohoku University
Heterocycles | Year: 2013

The synthesis history, physical properties (stability and tautomerism), ring construction procedures, a variety of reactions, various skeletons (monocyclic, bicyclic, tricyclic, tetracyclic, bicyclo-, and spiro-), and biological activities of dihydropyrimidines are reviewed. © 2013 The Japan Institute of Heterocyclic Chemistry. Source

Iwabuchi Y.,Tohoku University
Chemical and Pharmaceutical Bulletin | Year: 2013

The oxidation of primary and secondary alcohols to the corresponding aldehydes (or carboxylic acids) or ketones is a fundamental transformation in organic synthesis. Stable organic nitroxyl radicals as represented by 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) (1) have been used extensively to catalyze the oxidation of a number of alcohol substrates employing environmentally benign co-oxidants such as bleach (NaOCl) or PhI(OAc) 2. Although TEMPO oxidation is better known as a method for selective oxidation of primary alcohols to the corresponding aldehydes, the TEMPO-based method is not very efficient for the oxidation of structurally hindered secondary alcohols. We designed and synthesized 2-azaadamantane N-oxyl [AZADO (11)] and 1-Me-AZADO (20), a structurally less hindered class of nitroxyl radical. AZADOs were found to exhibit excellent catalytic activity enabling oxidation of a variety of alcohols with which TEMPO exhibits poor reactivity. Based on structure-activity relationships (SAR) employing AZADO (11), 1-Me-AZADO (20), 1,3-dimethyl-AZADO (33), 9-azabicyclo[3.3.1]nonane-N-oxyl [ABNO (34)] and 9-azanoradamantane N-oxyl [Nor-AZADO (37)], we concluded that the α-methyl group flanked nearby the nitroxyl group affects the reactivity for the oxidation of sterically hindered alcohols and the azaadamantane skeleton contributes to the high turnover of the catalyst. The highly active nature of AZADOs spurred us to exploit their further use in alcohol oxidations. A facile, green, one-pot oxidation of primary alcohols to carboxylic acids with broad substrate applicability has been developed by employing an expedient catalytic system consisting of the oxo-ammonium salt [1-Me-AZADO+X- (X=Cl, BF4)]/NaClO2. The synthetic use of AZADOs and the related nitroxyl radicals/oxoammonium salts-based methods for alcohol oxidation have been demonstrated in several total syntheses of natural products. We also describe the development of a Nor-AZADO (37)/DIAD/AcOH method that offers exceptionally mild and highly chemoselective oxidation of alcohols. © 2013 The Pharmaceutical Society of Japan. Source

PTEN-induced kinase 1 (PINK1), which is required for mitochondrial homeostasis, is a gene product responsible for early-onset Parkinson's disease (PD). Another early onset PD gene product, Parkin, has been suggested to function downstream of the PINK1 signalling pathway based on genetic studies in Drosophila. PINK1 is a serine/threonine kinase with a predicted mitochondrial target sequence and a probable transmembrane domain at the N-terminus, while Parkin is a RING-finger protein with ubiquitin-ligase (E3) activity. However, how PINK1 and Parkin regulate mitochondrial activity is largely unknown. To explore the molecular mechanism underlying the interaction between PINK1 and Parkin, we biochemically purified PINK1-binding proteins from human cultured cells and screened the genes encoding these binding proteins using Drosophila PINK1 (dPINK1) models to isolate a molecule(s) involved in the PINK1 pathology. Here we report that a PINK1-binding mitochondrial protein, PGAM5, modulates the PINK1 pathway. Loss of Drosophila PGAM5 (dPGAM5) can suppress the muscle degeneration, motor defects, and shorter lifespan that result from dPINK1 inactivation and that can be attributed to mitochondrial degeneration. However, dPGAM5 inactivation fails to modulate the phenotypes of parkin mutant flies. Conversely, ectopic expression of dPGAM5 exacerbated the dPINK1 and Drosophila parkin (dParkin) phenotypes. These results suggest that PGAM5 negatively regulates the PINK1 pathway related to maintenance of the mitochondria and, furthermore, that PGAM5 acts between PINK1 and Parkin, or functions independently of Parkin downstream of PINK1. Source

Ikoma N.,Tohoku University
Advanced Nonlinear Studies | Year: 2014

In this paper, the precompactness of minimizing sequences under multiconstraint conditions are discussed. This minimizing problem is related to a coupled nonlinear Schrödinger system which appears in the field of nonlinear optics. As a consequence of the compactness of each minimizing sequence, the orbital stability of the set of all minimizers is obtained. Source

Hiratsuka M.,Tohoku University
Drug Metabolism and Pharmacokinetics | Year: 2012

Summary: The cytochrome P450 (CYP) superfamily is one of the most important groups of enzymes involved in drug metabolism. It is responsible for the metabolism of a large number of drugs. Many CYP isoforms are expressed polymorphically, and catalytic alterations of allelic variant proteins can affect the metabolic activities of many drugs. The CYP2D6, CYP2C9, CYP2C19, and CYP2B6 genes are particularly polymorphic, whereas CYP1A1, CYP1A2, CYP2E1, and CYP3A4 are relatively well conserved without common functional polymorphisms. In vitro studies using cDNA expression systems are useful tools for evaluating functional alterations of the allelic variants of CYP, particularly for low-frequency alleles. Recombinant CYPs have been successfully expressed in bacteria, yeast, baculoviruses, and several mammalian cells. Determination of CYP variant-mediated kinetic parameters (K m and V max) in vitro can be useful for predicting drug dosing and clearance in humans. This review focuses on the advantages and disadvantages of the various cDNA-expression systems used to determine the kinetic parameters for CYP allelic variants, the methods for determining the kinetic parameters, and the findings of in vitro studies on highly polymorphic CYPs, including CYP2D6, CYP2C9, CYP2C19, and CYP2B6. © 2012 by the Japanese Society for the Study of Xenobiotics (JSSX). Source

Kubo H.,Tohoku University
Respirology | Year: 2012

Recent advances in stem cell research and tissue engineering have opened new paradigms for future therapies towards many intractable diseases. Many tissue engineering approaches are also applied in the pulmonary research field. Several materials have been utilized as scaffolds to support lung tissue engineering to recapitulate the three-dimensional (3D) structure of the lung. Natural products and synthetic polymers are the two major components of the scaffold materials. Decellularization of allogeneic or xenogenic donor lungs is also utilized to obtain biological 3D matrix scaffolds. Decellularized lungs are recellularized with stem or progenitor cells. Cell sources are the key components for tissue engineering. The best cell source for tissue engineering is autologous cells obtained from patients because it does not induce an immunological response after transplantation. However, the stem/progenitor population in adult organs is generally small, and their capacity for proliferation or differentiation is limited. Knowledge about the endogenous stem/progenitor population in lung tissue has been expanded recently. Although the lung is the most challenging organ for tissue engineering because of its complex 3D structure and more than 40 different cell types, several breakthroughs in respiratory research have been made. These results give us a greater understanding of the possibilities and the limitations of tissue engineering for pulmonary diseases. © 2012 Asian Pacific Society of Respirology. Source

Zhao D.,Tohoku University
Journal of Asian Earth Sciences | Year: 2015

We review recent findings on the causal mechanism of the great 2011 Tohoku earthquake (Mw 9.0) sequence and related issues on seismic structure and subduction dynamics in Western Pacific and East Asia. High-resolution tomography revealed significant lateral heterogeneities in the interplate megathrust zone beneath the Tohoku, South Kuril and Southwest Japan forearc regions. Large megathrust earthquakes since 1900 generally occurred in or around high-velocity (high-V) patches in the megathrust zone, which may reflect asperities resulting from subducted seamounts, oceanic ridges and other topographic highs on the Pacific seafloor. In contrast, low-velocity (low-V) patches in the megathrust zone may contain more sediments and fluids, where the subducting oceanic plate and the overlying continental plate are less coupled or even decoupled. The nucleation of large crustal earthquakes in the Japan Islands, including the 11 April 2011 Iwaki earthquake (M 7.0) in SE Tohoku, is affected by arc magma and fluids resulting from slab dehydration. The Philippine Sea plate has subducted aseismically down to 430-460. km depth under East China Sea, Tsushima Strait and Japan Sea. A window in the aseismic Philippine Sea slab is detected, which may be caused by splitting of weak parts of the slab at the subducted ridges (e.g., Kyushu-Paula ridge) and hot upwelling in the mantle wedge above the Pacific slab. The intraplate volcanism in Northeast Asia is caused by hot and wet upwelling flows in the big mantle wedge above the stagnant Pacific slab in the mantle transition zone. Frequent generation of large deep earthquakes (>500. km depth) in the Pacific slab may supply additional fluids preserved in the slab to the mantle wedge under the Changbai volcano, making Changbai the largest and most active intraplate volcano in Northeast Asia. Fluids may be involved in nucleation and rupture processes of all types of earthquakes. © 2014 The Authors. Source

Influenza infection tends to be severe in patients with chronic underlying diseases. This study evaluated the efficacy and safety of laninamivir octanoate, an inhaled neuraminidase inhibitor, for the treatment of influenza patients with chronic respiratory diseases; we conducted a double-blind, randomized controlled trial to compare the efficacy and safety of laninamivir octanoate and oseltamivir for the treatment of influenza in these patients. A total of 203 patients aged ≥20 years were randomized to receive either laninamivir octanoate or oseltamivir. The primary efficacy endpoint was the time to illness alleviation. This study is registered with JapicCTI; the registration number is JapicCTI-090940. The full analysis set (FAS) included a total of 201 patients (laninamivir group, n = 101; oseltamivir group, n = 100). Most patients had underlying bronchial asthma and 170 patients were infected with influenza A(H1N1)2009. The median time to illness alleviation was 64.7 h in the laninamivir group and 59.7 h in the oseltamivir group, with a difference of 5.0 h between the two groups (95 % confidence interval, -13.6 to 16.1 h). No adverse events specific to laninamivir octanoate were observed, and adverse events such as bronchospasm, which has been reported to be observed with other inhaled drugs related to laninamivir octanoate, did not occur. Laninamivir octanoate showed similar efficacy and safety to oseltamivir in the treatment of influenza, including that caused by influenza A(H1N1)2009, in patients with chronic respiratory diseases. © 2012 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Source

Since the discovery of α-glucosidase inhibitors and their inhibitory effects on the digestion of carbohydrates, promising results have been obtained as to the antidiabetic effects of this family of compounds. Antiangiogenic compounds have been identified that suppress tumor growth via a unique mechanism, confirming that such compounds can act as clinically applicable anticancer agents. Lipid peroxidation and lipid glycation have been suggested to play roles in food deterioration and in the pathophysiology of human diseases such as atherogenesis and diabetes, and antioxidative and antiglycative compounds can potentially be used in the prevention of food deterioration as well as to treat disease. On this basis, this review describes studies of -glucosidase inhibition by mulberry 1-deoxynojirimycin, antiangiogenic effects of rice bran tocotrienol, and membrane lipid peroxidation/glycation and its inhibitors. These studies are ongoing in our work, with an emphasis on analytical techniques. Source

Sasaki N.,Iwate Biotechnology Research Center | Nakayama T.,Tohoku University
Plant and Cell Physiology | Year: 2015

Genetic engineering of roses and other plants of floricultural importance to give them a truly blue petal color is arguably one of the holy grails of plant biotechnology. Toward this goal, bluish carnations and roses were previously engineered by establishing an exclusive accumulation of delphinidin (Dp)-type anthocyanins in their petals via the heterologous expression of a flavonoid 3′,5′-hydroxylase gene. Very recently, purple-blue varieties of chrysanthemums were also genetically engineered via a similar biochemical strategy. Although the floral colors of these transgenic plants still lack a true blue color, the basis for the future molecular breeding of truly blue flowers is via the engineering of anthocyanin pathways. Anthocyanins with multiple aromatic acyl groups (often referred to as polyacylated anthocyanins) in the 3′-or 7-position tend to display a more stable blue color than non-acylated anthocyanins. The 7-polyacylation process during the biosynthesis of purple-blue anthocyanins in delphinium (Delphinium grandiflorum) was found to occur in vacuoles using acyl-glucose as both the glucosyl and acyl donor. Glucosyltransferases and acyltransferases involved in anthocyanin 7-polyacylation in delphinium are vacuolar acyl-glucose-dependent enzymes belonging to the glycoside hydrolase family 1 and serine carboxypeptidae-like protein family, respectively. The 7-polyacylation proceeds through the alternate glucosylation and p-hydroxybenzoylation catalyzed by these enzymes. p-Hydroxybenzoyl-glucose serves as the p-hydroxybenzoyl and glucosyl donor to produce anthocyanins modified with a p-hydroxybenzoyl-glucose concatemer at the 7-position. This novel finding has provided a potential breakthrough for the genetic engineering of truly blue flowers, where polyacylated Dp-type anthocyanins are accumulated exclusively in the petals. © 2014 The Author. Source

Hansen F.,Tohoku University
Journal of Statistical Physics | Year: 2014

We consider both known and not previously studied trace functions with applications in quantum physics. By using perspectives we obtain convexity statements for different notions of residual entropy, including the entropy gain of a quantum channel studied by Holevo and others. We give new proofs of Carlen-Lieb's concavity/convexity theorems for certain trace functions, by making use of the theory of operator monotone functions. We then apply these methods in a study of new classes of trace functions. © 2013 Springer Science+Business Media New York. Source

The enantioselective total synthesis of (-)-scabronine G is described. The key features of the present synthesis include the construction of a 5-6 ring system containing two quaternary carbon centers via a diastereoselective intramolecular double Michael reaction and the formation of a seven-membered ring using a Prins cyclization. Source

Sugahara S.,Tokyo Institute of Technology | Sugahara S.,Japan Science and Technology Agency | Nitta J.,Tohoku University
Proceedings of the IEEE | Year: 2010

Spin transistors are a new concept device that unites an ordinary transistor with the useful functions of a spin (magnetoresistive) device. They are expected to be a building block for novel integrated circuits employing spin degrees of freedom. The interesting features of spin transistors are nonvolatile information storage and reconfigurable output characteristics: these are very useful and suitable functionalities for various new integrated circuit architectures that are inaccessible to ordinary transistor circuits. This article reviews the current status and outlook of spin transistors from the viewpoint of integrated circuit applications. The device structure, operating principle, performance, and features of various spin transistors are discussed. The fundamental and key phenomena/technologies for spin injection, transport, and manipulation in semiconductors and the integrated circuit applications of spin transistors to nonvolatile logic and reconfigurable logic are also described. © 2006 IEEE. Source

Inamoto K.,Tohoku University
Chemical and Pharmaceutical Bulletin | Year: 2013

Herein, we describe our development of synthetic methods for heterocyclic compounds based on the palladium-catalyzed carbon-hydrogen bond (C-H) functionalization/intramolecular carbon-heteroatom (nitrogen or sulfur) bond formation process. By this C-H cyclization method, we efficiently prepared various N-heterocycles, including indazoles, indoles, and 2-quinolinones, as well as S-heterocycles such as benzothiazoles and benzo[b]thiophenes. Yields are typically good to high and good functional-group tolerance is observed for each process, thereby indicating that the method provides a novel, highly applicable synthetic route to the abovementioned biologically important heterocyclic frameworks. As an application of this approach, an auto-tandem-type, one-pot process involving the oxidative Heck reaction and subsequent C-H cyclization using cinnamamides and arylboronic acids as starting materials in the presence of a palladium catalyst was also developed for the rapid construction of the 2-quinolinone nucleus. © 2013 The Pharmaceutical Society of Japan. Source

Nishimoto S.,Leibniz Institute for Solid State and Materials Research | Shibata N.,Tohoku University | Hotta C.,Kyoto Sangyo University
Nature Communications | Year: 2013

Quantum spin-1/2 kagome Heisenberg antiferromagnet is the representative frustrated system possibly hosting a spin liquid. Clarifying the nature of this elusive topological phase is a key challenge in condensed matter; however, even identifying it still remains unsettled. Here we apply a magnetic field and discover a series of spin-gapped phases appearing at five different fractions of magnetization by means of a grand canonical density matrix renormalization group, an unbiased state-of-the-art numerical technique. The magnetic field dopes magnons and first gives rise to a possible Z3 spin liquid plateau at 1/9 magnetization. Higher field induces a self-organized super-lattice unit, a six-membered ring of quantum spins, resembling an atomic orbital structure. Putting magnons into this unit one by one yields three quantum solid plateaus. We thus find that the magnetic field could control the transition between various emergent phases by continuously releasing the frustration. © 2013 Macmillan Publishers Limited. All rights reserved. Source

Suzuki O.,Tohoku University
Acta Biomaterialia | Year: 2010

Octacalcium phosphate (OCP), which is structurally similar to hydroxyapatite (HA), is a possible precursor of bone apatite crystals. Although disagreement remains as to whether OCP comprises the initial mineral crystals in the early stage of bone mineralization, the results of recent biomaterial studies using synthetic OCP indicate the potential role of OCP as a bone substitute material, owing to its highly osteoconductive and biodegradable characteristics. OCP tends to convert to HA not only in an in vitro environment, but also as an implant in bone defects. Several lines of evidence from both in vivo and in vitro studies suggest that the conversion process could be involved in the stimulatory capacity of OCP for osteoblastic differentiation and osteoclast formation. However, the osteoconductivity of OCP cannot always be secured if an OCP with distinct crystal characteristics is used, because the stoichiometry and microstructure of OCP crystals greatly affect bone-regenerative properties. Osteoconductivity and stimulatory capabilities may be caused by the chemical characteristics of OCP, which allows the release or exchange of calcium and phosphate ions with the surrounding of this salt, and its tendency to grow towards specific crystal faces, which could be a variable of the synthesis condition. This paper reviews the effect of calcium phosphates on osteoblastic activity and bone regeneration, with a special emphasis on OCP, since OCP seems to be performing better than other calcium phosphates in vivo. © 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved. Source

Shirota H.,Tohoku University | Klinman D.M.,U.S. National Cancer Institute
Expert Review of Vaccines | Year: 2014

CpG Oligonucleotides (ODN) are immunomodulatory synthetic oligonucleotides designed to specifically agonize Toll-like receptor 9. Here, we review recent progress in understanding the mechanism of action of CpG ODN and provide an overview of human clinical trial results using CpG ODN to improve the vaccines for cancer, allergy and infectious disease. © Informa UK, Ltd. Source

Makino T.,Trinity College Dublin | Makino T.,Tohoku University | McLysaght A.,Trinity College Dublin
Proceedings of the National Academy of Sciences of the United States of America | Year: 2010

About 30% of protein-coding genes in the human genome are related through two whole genome duplication (WGD) events. Although WGD is often credited with great evolutionary importance, the processes governing the retention of these genes and their biological significance remain unclear. One increasingly popular hypothesis is that dosage balance constraints are a major determinant of duplicate gene retention. We test this hypothesis and show that WGD-duplicated genes (ohnologs) have rarely experienced subsequent small-scale duplication (SSD) and are also refractory to copy number variation (CNV) in human populations and are thus likely to be sensitive to relative quantities (i.e., they are dosage-balanced). By contrast, genes that have experienced SSD in the vertebrate lineage are more likely to also display CNV. This supports the hypothesis of biased retention of dosage-balanced genes after WGD. We also show that ohnologs have a strong association with human disease. In particular, Down Syndrome (DS) caused by trisomy 21 is widely assumed to be caused by dosage effects, and 75% of previously reported candidate genes for this syndrome are ohnologs that experienced no other copy number changes. We propose the remaining dosage-balanced ohnologs on chromosome 21 as candidate DS genes. These observations clearly show a persistent resistance to dose changes in genes duplicated by WGD. Dosage balance constraints simultaneously explain duplicate gene retention and essentiality after WGD. Source

In this Account, we describe our efforts in the development of new synthetic strategies for the construction of N- and O-heterocycles by exploiting palladium-catalyzed reactions using enol phosphates as an electrophilic component. 1 Introduction 2 Suzuki-Miyaura Coupling of Lactone-Derived Enol Phosphates: A Convergent Synthetic Strategy toward trans-Fused Polycyclic Ether Marine Metabolites 3 Domino Intramolecular Heck/Diels-Alder Reaction of Imide-Derived Enol Phosphates toward the Synthesis of Fused N-Heterocycles 4 Strategies for the Synthesis of 2-Substituted Indoles and Indolines via Suzuki-Miyaura Coupling of Imide-Derived Enol Phosphates 5 Palladium-Catalyzed Reduction of Enol Phosphates: Total Synthesis of (±)-Lennoxamine and (±)-Chilenine 6 Suzuki-Miyaura Coupling of an Acetate-Derived Enol Phosphate: Total Synthesis of (+)-Neopeltolide 7 Concluding Remarks. © Georg Thieme Verlag Stuttgart - New York. Source

Hasegawa T.,Tohoku University
International Journal of Molecular Sciences | Year: 2010

Oxidized metabolites of dopamine known as dopamine quinone derivatives are thought to play a pivotal role in the degeneration of nigrostriatal dopaminergic neurons in Parkinson's disease. Although such quinone derivatives are usually produced via the autoxidation of catecholamines, tyrosinase, which is a key enzyme in melanin biosynthesis via the production of DOPA and subsequent molecules, can potentially accelerate the induction of catecholamine quinone derivatives by its oxidase activity. We have developed neuronal cell lines in which the expression of human tyrosinase was inducible. Overexpression of tyrosinase resulted in increased intracellular dopamine content in association with the formation of melanin pigments in neuronal somata, which eventually causes apoptotic cell death. This cellular model will provide a useful tool for detailed analyses of the neurotoxicity of oxidized catechol metabolites. © 2010 by the authors. Source

Takahashi Y.,Tohoku University | Tateda C.,University of Chicago
Apoptosis | Year: 2013

Voltage-dependent anion channels (VDACs), known as outer mitochondrial membrane proteins, are present in all eukaryotic cells. In mammals, they are now recognized to play crucial roles in the regulation of metabolic and energetic functions of mitochondria as well as in mitochondria-mediated apoptosis, in association with various proteins and non-protein modulators. Although there is much less information available for plant than for animal VDACs, their similar electrophysiological and topological properties suggest that some common functions are conserved among eukaryotic VDACs. Recently, it has been revealed that plant VDACs also have various important physiological functions not only in developmental and reproductive processes, but also in biotic and abiotic stress responses, including programmed cell death. In this review, we summarize recent findings about the sequence motifs, localization, and function of plant VDACs and discuss these results in the light of recent advances in research on animal VDACs. © 2013 Springer Science+Business Media New York. Source

Fujiwara K.,Tohoku University
International Journal of Photoenergy | Year: 2012

It is imperative to improve the crystal quality of Si multicrystal ingots grown by casting because they are widely used for solar cells in the present and will probably expand their use in the future. Fine control of macro- and microstructures, grain size, grain orientation, grain boundaries, dislocation/subgrain boundaries, and impurities, in a Si multicrystal ingot, is therefore necessary. Understanding crystal growth mechanisms in melt growth processes is thus crucial for developing a good technology for producing high-quality Si multicrystal ingots for solar cells. In this review, crystal growth mechanisms involving the morphological transformation of the crystal-melt interface, grain boundary formation, parallel-twin formation, and faceted dendrite growth are discussed on the basis of the experimental results of in situ observations. Copyright © 2012 Kozo Fujiwara. Source

Matsue T.,Tohoku University
Bulletin of the Chemical Society of Japan | Year: 2012

This article presents an overview of the recent progress made by our group in the development of bioelectrochemical devices and systems. The topics include intra- and extracellular measurements for the characterization of cellular functions, scanning electrochemical microscopy (SECM) with a probe-type micro/nanoelectrode, characterization of localized enzymes and membranes with SECM, characterization of live cells with SECM, high-resolution SECM systems for biological applications, cellular chips and devices for biosensing, cellular devices based on detection of gene expression, addressable micro/nanoelectrode arrays for multipoint measurements, and bioimaging microfluidic devices and dielectrophoretic devices with microelectrodes. © 2012 The Chemical Society of Japan. Source

Takahashi F.,Tohoku University | Takahashi F.,University of Tokyo
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2013

We revisit a single-field new inflation model based on a discrete R symmetry. Interestingly, the inflaton dynamics naturally leads to a heavy gravitino of mass m3/2=O(1-100)TeV, which is consistent with the standard-model like Higgs boson of mass mh≃126GeV. However, the predicted spectral index ns≈0.94 is in tension with the Planck result, ns=0.9603±0.073. We show that the spectral index can be increased by allowing a small constant term in the superpotential during inflation. The required size of the constant is close to the largest allowed value for successful inflation, and it may be a result of a pressure toward larger values in the landscape. Alternatively, such constant term may arise in association with supersymmetry breaking required to cancel the negative cosmological constant from the inflaton sector. © 2013 Elsevier B.V. Source

McCann E.,Lancaster University | Koshino M.,Tohoku University
Reports on Progress in Physics | Year: 2013

We review the electronic properties of bilayer graphene, beginning with a description of the tight-binding model of bilayer graphene and the derivation of the effective Hamiltonian describing massive chiral quasiparticles in two parabolic bands at low energies. We take into account five tight-binding parameters of the Slonczewski-Weiss-McClure model of bulk graphite plus intra- and interlayer asymmetry between atomic sites which induce band gaps in the low-energy spectrum. The Hartree model of screening and band-gap opening due to interlayer asymmetry in the presence of external gates is presented. The tight-binding model is used to describe optical and transport properties including the integer quantum Hall effect, and we also discuss orbital magnetism, phonons and the influence of strain on electronic properties. We conclude with an overview of electronic interaction effects. © 2013 IOP Publishing Ltd. Source

Dejene F.K.,Zernike Institute for Advanced Materials | Flipse J.,Zernike Institute for Advanced Materials | Bauer G.E.W.,Technical University of Delft | Bauer G.E.W.,Tohoku University | Van Wees B.J.,Zernike Institute for Advanced Materials
Nature Physics | Year: 2013

Since the discovery of the giant magnetoresistance effect the intrinsic angular momentum of the electron has opened up new spin-based device concepts. Our present understanding of the coupled transport of charge, spin and heat relies on the two-channel model for spin-up and spin-down electrons having equal temperatures. Here we report the observation of different (effective) temperatures for the spin-up and spin-down electrons in a nanopillar spin valve subject to a heat current. By three-dimensional finite element modelling of our devices for varying thickness of the non-magnetic layer, spin heat accumulations (the difference of the spin temperatures) of 120 mK and 350 mK are extracted at room temperature and 77 K, respectively, which is of the order of 10% of the total temperature bias over the nanopillar. This technique uniquely allows the study of inelastic spin scattering at low energies and elevated temperatures, which is not possible by spectroscopic methods. © 2013 Macmillan Publishers Limited. Source

Deguchi S.,Tohoku University
PLoS ONE | Year: 2011

The sound source of a voice is produced by the self-excited oscillation of the vocal folds. In modal voice production, a drastic increase in transglottal pressure after vocal fold closure works as a driving force that develops self-excitation. Another type of vocal fold oscillation with less pronounced glottal closure observed in falsetto voice production has been accounted for by the mucosal wave theory. The classical theory assumes a quasi-steady flow, and the expected driving force onto the vocal folds under wavelike motion is derived from the Bernoulli effect. However, wavelike motion is not always observed during falsetto voice production. More importantly, the application of the quasi-steady assumption to a falsetto voice with a fundamental frequency of several hundred hertz is unsupported by experiments. These considerations suggested that the mechanism of falsetto voice onset may be essentially different from that explained by the mucosal wave theory. In this paper, an alternative mechanism is submitted that explains how self-excitation reminiscent of the falsetto voice could be produced independent of the glottal closure and wavelike motion. This new explanation is derived through analytical procedures by employing only general unsteady equations of motion for flow and solids. The analysis demonstrated that a convective acceleration of a flow induced by rapid wall movement functions as a negative damping force, leading to the self-excitation of the vocal folds. The critical subglottal pressure and volume flow are expressed as functions of vocal fold biomechanical properties, geometry, and voice fundamental frequency. The analytically derived conditions are qualitatively and quantitatively reasonable in view of reported measurement data of the thresholds required for falsetto voice onset. Understanding of the voice onset mechanism and the explicit mathematical descriptions of thresholds would be beneficial for the diagnosis and treatment of voice diseases and the development of artificial vocal folds. © 2011 Shinji Deguchi. Source

Pu J.,Waseda University | Yomogida Y.,Waseda University | Yomogida Y.,Tohoku University | Liu K.-K.,Academia Sinica, Taiwan | And 4 more authors.
Nano Letters | Year: 2012

Molybdenum disulfide (MoS 2) thin-film transistors were fabricated with ion gel gate dielectrics. These thin-film transistors exhibited excellent band transport with a low threshold voltage (<1 V), high mobility (12.5 cm 2/(V ·s)) and a high on/off current ratio (10 5). Furthermore, the MoS 2 transistors exhibited remarkably high mechanical flexibility, and no degradation in the electrical characteristics was observed when they were significantly bent to a curvature radius of 0.75 mm. The superior electrical performance and excellent pliability of MoS 2 films make them suitable for use in large-area flexible electronics. © 2012 American Chemical Society. Source

Aoki M.,Tohoku University | Kanemura S.,University of Toyama
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2010

A general feature of TeV-scale radiative seesaw models, in which tiny neutrino masses are generated via loop corrections, is an extended scalar (Higgs) sector. Another feature is the Majorana nature; e.g., introducing right-handed neutrinos with TeV-scale Majorana masses under the discrete symmetry, or otherwise introducing some lepton number violating interactions in the scalar sector. We study phenomenological aspects of these models at collider experiments. We find that, while properties of the extended Higgs sector of these models can be explored to some extent, the Majorana nature of the models can also be tested directly at the International Linear Collider via the electron-positron and electron-electron collision experiments. © 2010 Elsevier B.V. All rights reserved. Source

Hotta M.,Tohoku University
Physics Letters, Section A: General, Atomic and Solid State Physics | Year: 2010

Protocols of quantum energy teleportation (QET), while retaining causality and local energy conservation, enable the transportation of energy from a subsystem of a many-body quantum system to a distant subsystem by local operations and classical communication through ground-state entanglement. We prove two energy-entanglement inequalities for a minimal QET model. These relations help us to gain a profound understanding of entanglement itself as a physical resource by relating entanglement to energy as an evident physical resource. © 2010 Elsevier B.V. Source

Kiyo Y.,Juntendo University | Sumino Y.,Tohoku University
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2014

We compute the energy levels of some of the lower-lying heavy quarkonium states perturbatively up to O(αs5m) and O(αs5mlogαs). Stability of the predictions depends crucially on the unknown 4-loop pole- MS- mass relation. We discuss the current status of the predictions with respect to the observed bottomonium spectrum. © 2014 The Authors. Source

Nakayama K.,University of Tokyo | Takahashi F.,Tohoku University | Takahashi F.,University of Tokyo | Yanagida T.T.,University of Tokyo
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2014

We propose a chaotic inflation model in which the lightest right-handed sneutrino serves as the inflaton and the predicted values of the spectral index and tensor-to-scalar ratio are consistent with the Planck data. Interestingly, the observed magnitude of primordial density perturbations is naturally explained by the inflaton mass of order 1013GeV, which is close to the right-handed neutrino mass scale suggested by the seesaw mechanism and the neutrino oscillation experiments. We find that the agreement of the two scales becomes even better in the neutrino mass anarchy. We show that the inflation model can be embedded into supergravity and discuss thermal history of the Universe after inflation such as non-thermal leptogenesis by the right-handed sneutrino decays and the modulus dynamics. © 2014 The Authors. Source

Higaki T.,High Energy Accelerator Research Organization | Takahashi F.,Tohoku University | Takahashi F.,University of Tokyo
Journal of High Energy Physics | Year: 2014

We propose a landscape of many axions, where the axion potential receives various contributions from shift symmetry breaking effects. We show that the existence of the axion with a super-Planckian decay constant is very common in the axion landscape for a wide range of numbers of axions and shift symmetry breaking terms, because of the accidental alignment of axions. The effective inflation model is either natural or multi-natural inflation in the axion landscape, depending on the number of axions and the shift symmetry breaking terms. The tension between BICEP2 and Planck could be due to small modulations to the inflaton potential or steepening of the potential along the heavy axions after the tunneling. The total duration of the slow-roll inflation our universe experienced is not significantly larger than 60 if the typical height of the axion potentials is of order (1016-17 GeV)4. © 2014 The Author(s). Source

Nakayama K.,University of Tokyo | Takahashi F.,Tohoku University | Takahashi F.,University of Tokyo
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2014

We show that the standard model Higgs field can realize the quadratic chaotic inflation, if the kinetic term is significantly modified at large field values. This is a simple realization of the so-called running kinetic inflation. The point is that the Higgs field respects an approximate shift symmetry at high energy scale. The tensor-to-scalar ratio is predicted to be r ≃ 0.13-0.16, which nicely explains the primordial B-mode polarization, r=0.20-0.05+0.07, recently discovered by the BICEP2 experiment. In particular, allowing small modulations induced by the shift symmetry breaking, the negative running spectral index can also be induced. The reheating temperature is expected to be so high that successful thermal leptogenesis is possible. The suppressed quartic coupling of the Higgs field at high energy scales may be related to the Higgs chaotic inflation. © 2014 The Authors. Source

Nakayama K.,University of Tokyo | Takahashi F.,Tohoku University | Takahashi F.,University of Tokyo | Yanagida T.T.,University of Tokyo
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2014

We pursue a possibility that a pseudo-Nambu-Goldstone boson is lurking around or below the intermediate scale. To this end we consider an anomaly-free global flavor symmetry, and construct models where the pseudo-Nambu-Goldstone boson is coupled preferentially to leptons. The experimental and astrophysical bounds derived from couplings to photons and nucleons are significantly relaxed. If sufficiently light, the pseudo-Nambu-Goldstone boson contributes to dark matter, and interestingly, it generally decays into photons through couplings arising from threshold corrections. We show that the recent hint for the X-ray line at about 3.5 keV can be explained by the decay of such pseudo-Nambu-Goldstone boson of mass about 7 keV with the decay constant of order 1010 GeV, if the electron is charged under the flavor symmetry. © 2014 The Authors. Source

Nakayama K.,University of Tokyo | Takahashi F.,Tohoku University | Takahashi F.,University of Tokyo | Yanagida T.T.,University of Tokyo
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2014

The recent unidentified 3.5 keV X-ray line signal can be explained by decaying moduli dark matter with a cutoff scale one order of magnitude smaller than the Planck scale. We show that such modulus field with the low cutoff scale follows a time-dependent potential minimum and its abundance is reduced by the adiabatic suppression mechanism. As a result the modulus abundance can naturally be consistent with the observed dark matter abundance without any fine-tuning of the initial oscillation amplitude. © 2014 Elsevier B.V. Source

Sumino Y.,Tohoku University
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2014

We estimate the presently unknown constant in the 4-loop relation between the quark pole mass and the MS mass, by requiring stability of the perturbative prediction for Etot(r) = 2mpole + VQCD(r) in the intermediate-distance region. The estimate is fairly sharp due to a severe cancellation between 2mpole and VQCD(r). This would provide a test, based on general properties of the gauge theory, for the size of ultra-soft contributions to VQCD(r) © 2013 The Author. Published by Elsevier B.V. Source

Hoshino S.,University of Tokyo | Kuramoto Y.,Tohoku University
Physical Review Letters | Year: 2014

Emergence of odd-frequency s-wave superconductivity is demonstrated in the two-channel Kondo lattice by means of the dynamical mean-field theory combined with the continuous-time quantum Monte Carlo method. Around half filling of the conduction bands, divergence of an odd-frequency pairing susceptibility is found, which signals instability toward the superconductivity. The corresponding order parameter is equivalent to a staggered composite-pair amplitude with even frequencies, which involves both localized spins and conduction electrons. A model wave function is constructed for the composite order with the use of symmetry operations such as charge conjugation and channel rotations. Given a certain asymmetry of the conduction bands, another s-wave superconductivity is found that has a uniform order parameter. The Kondo effect in the presence of two channels is essential for both types of unconventional superconductivity. © 2014 American Physical Society. Source

Videogame play (VGP) has been associated with numerous preferred and non-preferred effects. However, the effects of VGP on the development of microstructural properties in children, particularly those associated with negative psychological consequences of VGP, have not been identified to date. The purpose of this study was to investigate this issue through cross-sectional and longitudinal prospective analyses. In the present study of humans, we used the diffusion tensor imaging mean diffusivity (MD) measurement to measure microstructural properties and examined cross-sectional correlations with the amount of VGP in 114 boys and 126 girls. We also assessed correlations between the amount of VGP and longitudinal changes in MD that developed after 3.0±0.3 (s.d.) years in 95 boys and 94 girls. After correcting for confounding factors, we found that the amount of VGP was associated with increased MD in the left middle, inferior and orbital frontal cortex; left pallidum; left putamen; left hippocampus; left caudate; right putamen; right insula; and thalamus in both cross-sectional and longitudinal analyses. Regardless of intelligence quotient type, higher MD in the areas of the left thalamus, left hippocampus, left putamen, left insula and left Heschl gyrus was associated with lower intelligence. We also confirmed an association between the amount of VGP and decreased verbal intelligence in both cross-sectional and longitudinal analyses. In conclusion, increased VGP is directly or indirectly associated with delayed development of the microstructure in extensive brain regions and verbal intelligence.Molecular Psychiatry advance online publication, 5 January 2016; doi:10.1038/mp.2015.193. © 2016 Macmillan Publishers Limited Source

Golestanian R.,University of Oxford | Yeomans J.M.,University of Oxford | Uchida N.,Tohoku University
Soft Matter | Year: 2011

After a long gap following the classic work of Taylor, there have recently been several studies dealing with hydrodynamic synchronization. It is now apparent that synchronization driven by hydrodynamic interactions is not only possible, but relevant to the efficiency of pumping by arrays of cilia and to bacterial swimming. Recent work has included experiments demonstrating synchronization, both in model systems and between bacterial flagella. The effect has been demonstrated in model swimmers and pumps, and large scale simulations have been used to investigate synchronization of cilia and of sperm cells. In this review article, we summarize the various experimental and theoretical studies of hydrodynamic synchronization, and put them in a framework which draws parallels between the different systems and suggests useful directions for further research. © The Royal Society of Chemistry 2011. Source

Kuroishi T.,Tohoku University
Canadian Journal of Physiology and Pharmacology | Year: 2015

Biotin is a water-soluble B-complex vitamin and is well-known as a co-factor for 5 indispensable carboxylases. Holocarboxylase synthetase (HLCS) catalyzes the biotinylation of carboxylases and other proteins, whereas biotinidase catalyzes the release of biotin from biotinylated peptides. Previous studies have reported that nutritional biotin deficiency and genetic defects in either HLCS or biotinidase induces cutaneous inflammation and immunological disorders. Since biotin-dependent carboxylases involve various cellular metabolic pathways including gluconeogenesis, fatty acid synthesis, and the metabolism of branched-chain amino acids and odd-chain fatty acids, metabolic abnormalities may play important roles in immunological and inflammatory disorders caused by biotin deficiency. Transcriptional factors, including NF-[1]B and Sp1/3, are also affected by the status of biotin, indicating that biotin regulates immunological and inflammatory functions independently of biotin-dependent carboxylases. An in-vivo analysis with a murine model revealed the therapeutic effects of biotin supplementation on metal allergies. The novel roles of biotinylated proteins and their related enzymes have recently been reported. Non-carboxylase biotinylated proteins induce chemokine production. HLCS is a nuclear protein involved in epigenetic and chromatin regulation. In this review, comprehensive knowledge on the regulation of immunological and inflammatory functions by biotin and its potential as a therapeutic agent is discussed. © 2015, National Research Council of Canada . All Rights Reserved. Source

Joint immobilization is commonly used for the treatment of joint injuries and diseases, but it also causes unfavorable outcomes such as joint contracture. The purpose of this study was to examine the morphological changes of the synovial membrane that is suspected as a cause of joint contracture, and localization of type A (macrophage-like) and type B (fibroblast-like) synoviocytes in the capsule after joint immobilization. Male Sprague-Dawley rats were used in this study. Unilateral knee joints were rigidly immobilized at 150 degrees of flexion with internal fixators for 3 days, 1, 2, 4, 8, and 16 weeks (7 rats/each immobilized group), while 42 rats were sham-operated. Sagittal sections of 5 mum were prepared from the medial midcondylar region of the knee joints and assessed with histological, histomorphometric, and immunohistochemical methods. Adhesions were observed both in the anterior and posterior synovial membranes in the immobilized group after 2 weeks. In the adhesion area, the cells were mainly composed of type A synoviocytes that were positive for CD68 and type B synoviocytes positive for prolyl 4-hydroxylase subunit beta. The length of synovial membrane in the immobilized group was significantly shorter than that in the control group after 2 and 4 weeks. After 8 weeks, the adhesion area in the immobilized group became fibrous and hypocellular. The staining intensity of hyaluronic acid-binding protein was increased after 16 weeks. Adhesion and shortening of the synovial membrane and the structural changes of the adhesion area may contribute to the development of joint contracture. Source

Osada N.,Tohoku University | Osada N.,Kyoto University
Functional Ecology | Year: 2011

1. Tree allometry often varies among coexisting species of different maximum height (Hmax) in forests. Although shoot growth patterns directly influence overall tree architecture, the structures of current-year shoots at the tops of crowns have not been directly related to differences in tree allometry across species. 2. I investigated height-dependent changes in structure and biomass allocation patterns in current-year shoots of four coexisting tree species differing in Hmax in a cool-temperate forest in Japan. The relative importance of total biomass, biomass allocation, shoot allometry, and shoot angle to vertical growth was quantified and compared with tree allometry. 3. Height-dependent changes in total biomass of current-year shoots varied across species. In contrast, stem length per unit mass, shoot angle, and total leaf area per unit stem cross-sectional area decreased, and leaf mass per unit area increased with height in all species. Vertical growth rate consequently declined with increasing height in all species. Sensitivity analyses revealed that the primary determinant of declining vertical growth rate was change in stem length per unit mass; shoot angle was a secondary determinant. In contrast, increases in total shoot mass with height modulated declining vertical growth rates. 4. Vertical growth rate was greater in two canopy species than in two sub-canopy species at given heights at the shoot level, and this pattern coincided with allometry between tree height and trunk diameter. In contrast, vertical growth rate was greater in sub-canopy species than in canopy species near their maximum heights. These patterns suggest that allometric differences between species may be useful for evaluating crown-development patterns, but not for estimating Hmax of species. © 2011 The Author. Functional Ecology © 2011 British Ecological Society. Source

Satoh K.,Tohoku University
Tohoku Journal of Experimental Medicine | Year: 2014

Vascular homeostasis is regulated by complex interactions between many vascular cell components, including endothelial cells, vascular smooth muscle cells (VSMCs), adventitial inflammatory cells, and autonomic nervous system. The balance between oxidant and antioxidant systems determines intracellular redox status, and their imbalance can cause oxidative stress. Excessive oxidative stress is one of the important stimuli that induce cellular damage and dysregulation of vascular cell components, leading to vascular diseases through multiple pathways. Cyclophilin A (CyPA) is one of the causative proteins that mediate oxidative stress-induced cardiovascular dysfunction. CyPA was initially discovered as the intracellular receptor of the immunosuppressive drug cyclosporine 30 years ago. However, recent studies have established that CyPA is secreted from vascular cell components, such as endothelial cells and VSMCs. Extracellular CyPA augments the development of cardiovascular diseases. CyPA secretion is regulated by Rho-kinase, which contributes to the pathogenesis of vasospasm, arteriosclerosis, ischemia/ reperfusion injury, hypertension, pulmonary hypertension, and heart failure. We recently reported that plasma CyPA levels are significantly higher in patients with coronary artery disease, which is associated with increased numbers of stenotic coronary arteries and the need for coronary intervention in such patients. Furthermore, we showed that the vascular erythropoietin (Epo)/Epo receptor system plays an important role in production of nitric oxide and maintenance of vascular redox state and homeostasis, with a potential mechanistic link to the Rho-kinase-CyPA pathway. In this article, I review the data on the protective role of the vascular Epo/Epo receptor system and discuss the roles of the CyPA/Rho-kinase system in cardiovascular diseases. © 2014, Tohoku University Medical Press. All rights reserved. Source

Mori E.,Tohoku University
Annals of the New York Academy of Sciences | Year: 2012

Although the internationally recommended dosage of alteplase, a single-chain rt-PA, is 0.9 mg/kg, 0.6 mg/kg is the only approved dosage in Japan, and it is widely used there. Duteplase is a two-chain rt-PA, and based on findings of the duteplase trials in the early 1990s, the smaller dosage of 0.6 mg/kg of alteplase was tested in the Japan Alteplase Clinical Trial (J-ACT), which indicated that the efficacy/safety profile of this dose was comparable to the 0.9 mg/kg dosage used in other countries. The Japan Alteplase Clinical Trial II (J-ACT II) further demonstrated efficacy of 0.6 mg/kg alteplase with regard to vascular outcomes in patients with middle cerebral artery (MCA) occlusion. Finally, the Japan post-Marketing Alteplase Registration Study (J-MARS) confirmed the efficacy/safety profile of 0.6 mg/kg alteplase in a clinical setting that was comparable to the dose of 0.9 mg/kg in the European counterpart, the Safe Implementation of Thrombolysis in Stroke-Monitoring Study (SITS-MOST). The dose of 0.6 mg/kg seems to be optimal, at least in far-east Asians, and might be extrapolated to other ethnic groups as well. © 2012 New York Academy of Sciences. Source

Nonogaki K.,Tohoku University
Vitamins and Hormones | Year: 2012

Short sleep duration has been suggested to be a risk factor for weight gain and adiposity. Serotonin (5-HT) substantially contributes to the regulation of sleep and feeding behavior. Although 5-HT predominately promotes waking and satiety, the effects of 5-HT depend on 5-HT receptor function. The 5-HT1A, 5-HT1B, 5-HT2A, 5-HT2C, 5-HT6, and 5-HT7 receptors reportedly contribute to sleep-waking regulation, whereas the 5-HT1B and 5-HT2C receptors contribute to the regulation of satiety. The 5-HT1B and 2C receptors may therefore be involved in the regulation of sleep-feeding.In genetic studies, 5-HT1B receptor mutant mice display greater amounts of rapid eye movement sleep (REMS) than wild-type mice, while displaying no effects on waking or slow wave sleep (SWS). On the other hand, 5-HT2C receptor mutant mice exhibit increased wakefulness and decreased SWS, without any effect on REMS. Moreover, the 5-HT2C receptor mutants display leptin-independent hyperphagia, leading to a middle-aged onset of obesity, whereas 5-HT1B receptor mutants do not display any effect on food intake. Thus, the genetic deletion of 5-HT2C receptors results in sleep loss-associated hyperphagia, leading to the late onset of obesity. This is a quite different pattern of sleep-feeding behavior than is observed in disturbed leptin signaling, which displays an increase in sleep-associated hyperphagia.In pharmacologic studies, 5-HT1B and 5-HT2C receptors upregulate wakefulness and downregulate SWS, REMS, and food intake. These findings suggest that 5-HT1B/2C receptor stimulation induces sleep loss-associated anorexia. Thus, the central 5-HT regulation of sleep-feeding can be dissociated. Functional hypothalamic proopiomelanocortin and orexin activities may contribute to the dissociated 5-HT regulation. © 2012 Elsevier Inc.. Source

Shimokawa H.,Tohoku University
European Heart Journal | Year: 2014

Coronary vasomotion abnormalities play important roles in the pathogenesis of ischaemic heart disease, in which endothelial dysfunction and coronary artery spasm are substantially involved. Endothelial vasodilator functions are heterogeneous depending on the vessel size, with relatively greater role of nitric oxide (NO) in conduit arteries and predominant role of endothelium-derived hyperpolarizing factor (EDHF) in resistance arteries, where endothelium-derived hydrogen peroxide serves as an important EDHF. The functions of NO synthases in the endothelium are also heterogeneous with multiple mechanisms involved, accounting for the diverse functions of the endothelium in vasomotor as well as metabolic modulations. Cardiovascular abnormalities and metabolic phenotypes become evident when all three NO synthases are deleted, suggesting the importance of both NO and EDHF. Coronary artery spasm plays important roles in the pathogenesis of a wide range of ischaemic heart disease. The central mechanism of the spasm is hypercontraction of vascular smooth muscle cells (VSMCs), but not endothelial dysfunction, where activation of Rho-kinase, a molecular switch of VSMC contraction, plays a major role through inhibition of myosin light-chain phosphatase. The Rho-kinase pathway is also involved in the pathogenesis of a wide range of cardiovascular diseases and new Rho-kinase inhibitors are under development for various indications. The registry study by the Japanese Coronary Spasm Association has demonstrated many important aspects of vasospastic angina. The ongoing international registry study of vasospastic angina in six nations should elucidate the unknown aspects of the disorder. Coronary vasomotion abnormalities appear to be an important therapeutic target in cardiovascular medicine. © 2014 Published on behalf of the European Society of Cardiology. Source

Kudo Y.,Tohoku University
International journal of hematology | Year: 2011

Total nucleated cell (TNC) count, CD34(+) cell count, colony-forming unit-granulocyte-macrophage (CFU-GM) content, and cell viability impact the outcome of umbilical cord blood (UCB) transplantation. Assessments of unit quality have usually been provided by cord blood banks (CBBs), but it is unclear whether pre-freezing tests or pre-transplant release tests performed by CBBs are reproducible. The aim of this study was to compare the UCB characteristics analyzed at the site of infusion of the UCB with those provided by CBBs. Samples were taken from 54 UCB units for assessment of post-thaw characteristics. TNC counts and CD34(+) cell contents measured at our hospital before infusion showed good correlations with values assessed in pre-freezing tests (r = 0.900 and 0.943, respectively) and pre-transplant release tests (r = 0.829 and 0.930, respectively). Our data reveal that the TNC counts and CD34(+) cell contents determined by pre-freezing and pre-transplant release tests, which are the most important UCB unit selection criteria, accurately reflected the quality of infused UCB units. However, CFU-GM content was poorly correlated (r = 0.560 and 0.606). Correlation of post-thaw cell viabilities measured before infusion and during the pre-transplant release tests was also poor (r = 0.308). We suggest that the TNC count and CD34(+) cell content estimated before cryopreservation and in pre-transplant release tests provided by CBBs are reproducible and can assist the transplant physicians in selection of appropriate UCB units. Source

Chronic left ventricular (LV) pressure overload induced by hypertension is one of the most common causes of heart failure. Earlier reports have shown the cardioprotective effects of erythropoietin (EPO). In the present study, we tested the hypothesis that recombinant human EPO exerts a protective effect against pressure-overload induced LV remodeling. Mice subjected to transverse aortic constriction (TAC) (n = 70) were randomly assigned to the treatment with phosphate buffer solution (PBS) (TAC-PBS) or EPO (2,000 U/kg twice a week) (TAC-EPO). At 8 weeks after TAC, LV weight was comparably increased in both TAC groups compared with sham-operated mice (Sham) (both P < 0.001). The treatment with EPO improved the survival of TAC mice as compared with treatment with PBS (80 vs. 47%, P < 0.01), which was associated with reductions in the extent of myocardial fibrosis and the number of TUNEL positive cardiomyocytes (both P < 0.05). Echocardiography revealed that TAC increased LV chamber diameter and decreased LV fractional shortening compared with Sham (P < 0.05), which was ameliorated by the treatment with EPO (P < 0.05). In TAC-EPO as compared to TAC-PBS, phosphorylation of STAT3, Akt and eNOS was all increased, while phosphorylation of p38 was decreased (all P < 0.05). Importantly, the expression level of VEGF and the capillary density in LV myocardium were similar among the 3 groups. These results suggest that recombinant human EPO ameliorates the cardiac remodeling and the premature death associated with chronic LV pressure overload through the mechanisms independent of angiogenesis. Source

Tanimura Y.,University Paris - Sud | Lacroix D.,University Paris - Sud | Scamps G.,Tohoku University
Physical Review C - Nuclear Physics | Year: 2015

Given a set of collective variables, a method is proposed to obtain the associated conjugated collective momenta and masses starting from a microscopic time-dependent mean-field theory. The construction of pairs of conjugated variables is the first step to bridge microscopic and macroscopic approaches. The method is versatile and can be applied to study a large class of nuclear processes. An illustration is given here with the fission of Fm258. Using the quadrupole moment and eventually higher-order multipole moments, the associated collective masses are estimated along the microscopic mean-field evolution. When more than one collective variable is considered, it is shown that the off-diagonal matrix elements of the inertia play a crucial role. Using the information on the quadrupole moment and associated momentum, the collective evolution is studied. It is shown that dynamical effects beyond the adiabatic limit are important. Nuclei formed after fission tend to stick together for a longer time leading to a dynamical scission point at a larger distance between nuclei compared to the one anticipated from the adiabatic energy landscape. The effective nucleus-nucleus potential felt by the emitted nuclei is finally extracted. © 2015 American Physical Society. ©2015 American Physical Society. Source

Koyanagi M.,Tohoku University
IEEE International Reliability Physics Symposium Proceedings | Year: 2011

Three-dimensional (3D) integration technologies including a new 3D heterogeneous integration of super-chip are described. In addition, reliability issues in these 3D LSIs such as mechanical stresses induced by through-silicon vias (TSVs) and metal microbumps and Cu contamination in thinned wafers are discussed. Cu TSVs with the diameter of 20μm induced the maximum compressive stress of ∼1 GPa at the silicon substrate adjacent to them after annealed at 300°C for 30 min. Mechanical strain/stress and crystal defects were produced in extremely thin wafers (thickness ∼10μm) of 3D LSIs not only during wafer thinning, but also after wafer bonding using fine-pitch, high-density metal microbumps and curing. The influence of Cu contamination at the back surface of the thinned wafer has been evaluated by C-t analysis. C-t curves measured in MOS capacitors without IG layer and EG layer were seriously degraded after annealing even at 200°C whereas the C-t curves exhibited only a little change even after annealing up to 350 min at 300°C. It was revealed that the generation lifetime of minority carrier is significantly reduced by the Cu contamination. © 2011 IEEE. Source

Ishigaki M.N.,University of Tokyo | Aoki W.,Japan National Astronomical Observatory | Chiba M.,Tohoku University
Astrophysical Journal | Year: 2013

We present chemical abundance analyses of sodium, iron-peak, and neutron-capture elements for 97 kinematically selected thick disk, inner halo, and outer halo stars with metallicities -3.3 < [Fe/H] <-0.5. The main aim of this study is to examine chemical similarities and differences among metal-poor stars belonging to these old Galactic components as a clue to determine their early chemodynamical evolution. In our previous paper, we obtained abundances of α elements by performing a one-dimensional LTE abundance analysis based on the high-resolution (R ∼ 50, 000) spectra obtained with the Subaru/HDS. In this paper, a similar analysis is performed to determine abundances of an additional 17 elements. We show that, in metallicities below [Fe/H] ∼-2, the abundance ratios of many elements in the thick disk, inner halo, and outer halo subsamples are largely similar. In contrast, in higher metallicities ([Fe/H] ≳ -1.5), differences in some of the abundance ratios among the three subsamples are identified. Specifically, the [Na/Fe], [Ni/Fe], [Cu/Fe], and [Zn/Fe] ratios in the inner and outer halo subsamples are found to be lower than those in the thick disk subsample. A modest abundance difference between the two halo subsamples in this metallicity range is also seen for the [Na/Fe] and [Zn/Fe] ratios. In contrast to that observed for [Mg/Fe] in our previous paper, [Eu/Fe] ratios are more enhanced in the two halo subsamples rather than in the thick disk subsample. The observed distinct chemical abundances of some elements between the thick disk and inner/outer halo subsamples with [Fe/H] >-1.5 support the hypothesis that these components formed through different mechanisms. In particular, our results favor the scenario that the inner and outer halo components formed through an assembly of multiple progenitor systems that experienced various degrees of chemical enrichments, while the thick disk formed through rapid star formation with an efficient mixing of chemical elements. The lower [Na/Fe] and [Zn/Fe] observed in stars with the outer halo kinematics may further suggest that progenitors with longer star formation timescales contributed to the buildup of the relatively metal-rich part of stellar halos. © 2013. The American Astronomical Society. All rights reserved. Source

Hamada I.,Tohoku University
Physical Review B - Condensed Matter and Materials Physics | Year: 2012

The van der Waals density functional (vdW-DF) was used to investigate the interaction of a water monomer with graphene. It was found that a variant of vdW-DF predicts geometries and energetics of water on graphene which are in good agreement with those obtained using more elaborate random-phase approximation and quantum Monte Carlo approaches. Interfacial electronic structures were also analyzed in detail. © 2012 American Physical Society. Source

Ishigaki M.N.,Japan National Astronomical Observatory | Chiba M.,Tohoku University | Aoki W.,Japan National Astronomical Observatory
Astrophysical Journal | Year: 2012

We present the abundance analysis of 97 nearby metal-poor (-3.3 < [Fe/H] <-0.5) stars having kinematic characteristics of the Milky Way (MW) thick disk and inner and outer stellar halos. The high-resolution, high-signal-to-noise optical spectra for the sample stars have been obtained with the High Dispersion Spectrograph mounted on the Subaru Telescope. Abundances of Fe, Mg, Si, Ca, and Ti have been derived using a one-dimensional LTE abundance analysis code with Kurucz NEWODF model atmospheres. By assigning membership of the sample stars to the thick disk, inner halo, or outer halo components based on their orbital parameters, we examine abundance ratios as a function of [Fe/H] and kinematics for the three subsamples in wide metallicity and orbital parameter ranges. We show that, in the metallicity range of -1.5 < [Fe/H] ≤-0.5, the thick disk stars show constantly high mean [Mg/Fe] and [Si/Fe] ratios with small scatter. In contrast, the inner and the outer halo stars show lower mean values of these abundance ratios with larger scatter. The [Mg/Fe], [Si/Fe], and [Ca/Fe] for the inner and the outer halo stars also show weak decreasing trends with [Fe/H] in the range [Fe/H] >-2. These results favor the scenarios that the MW thick disk formed through rapid chemical enrichment primarily through Type II supernovae of massive stars, while the stellar halo has formed at least in part via accretion of progenitor stellar systems having been chemically enriched with different timescales. © 2012. The American Astronomical Society. All rights reserved. Source

Lee U.,Tohoku University
Monthly Notices of the Royal Astronomical Society | Year: 2012

Using the weakly non-linear theory of oscillation, we estimate the amplitudes of low-frequency modes in a slowly pulsating B star, taking account of the effects of rotation on the modes. Applying the formulation by Schenk et al., we compute the non-linear coupling coefficient between the low-frequency modes and estimate the equilibrium amplitudes of the modes excited in the star, assuming the amplitudes of the unstable modes are saturated as a result of non-linear coupling with stable modes, i.e. as a result of parametric instability expected between one unstable mode and two stable modes. We use the traditional approximation to calculate adiabatic and non-adiabatic oscillations in a rotating star. We find r-modes in a rapidly rotating star play a significant role in the amplitude determination through non-linear coupling. We also find that for low-m modes, the fractional amplitudes of the radiative luminosity caused by the low-frequency modes are of order 10 -4 to 10 -3 at the surface. © 2012 The Author Monthly Notices of the Royal Astronomical Society © 2012 RAS. Source

Okura Y.,Japan National Astronomical Observatory | Futamase T.,Tohoku University
Astrophysical Journal | Year: 2012

We developed a new method (E-HOLICs) of estimating gravitational shear by adopting an elliptical weight function to measure background galaxy images in our previous paper. Following the previous paper, in which an isotropic point-spread function (PSF) correction is calculated, in this paper we consider an anisotropic PSF correction in order to apply E-HOLICs to real data. As an example, E-HOLICs is applied to Subaru data of the massive and compact galaxy cluster A370 and is able to detect double peaks in the central region of the cluster consistent with the analysis of strong lensing. We also study the systematic error in E-HOLICs using STEP2 simulation. In particular, we consider the dependences of the signal-to-noise ratio (S/N) of background galaxies in the shear estimation. Although E-HOLICs does improve the systematic error due to the ellipticity dependence as shown in Paper I, a systematic error due to the S/N dependence remains, namely, E-HOLICs underestimates shear when background galaxies with low S/N objects are used. We discuss a possible improvement of the S/N dependence. © 2012. The American Astronomical Society. All rights reserved. Source

Hongo M.,Tohoku University
Journal of Gastroenterology and Hepatology (Australia) | Year: 2011

Objective and Background: Gastrointestinal symptoms are quite common among the general population, but different survey methods show different epidemiology, and the effect of psychosocial and behavioral factors on the symptoms have been studied mainly by the subgroup The aims of this studies are; 1: to clarify the difference of the survey methods on the epidemiology of FGID symptoms, 2: correlation with psycho-behavioral background in symptomatic subjects. Methods: Questionnaires focused on GI symptoms and psycho-behavioral background were generated. Questionnaires were sent via e-mail and postal mail to the members of the registered panel. Results: A total of 2125 and 11020 responses were recovered from electronic survey and postal survey. Significant difference in the prevalence of GI symptoms, 47% in electronic survey and 25% in postal survey, were observed. Despite the difference in the prevalence, the proportions of symptom subtypes and the patterns of the overlaps were similar in the two methods. In the analysis of the effect of psycho-behavioral factors, this study showed that those who have higher level of psycho-behavioral problem had higher prevalence of GERD, FD and IBS symptoms. Those who have impairment in the wellness sensation such as good eating, good bowel movement and good sleep showed higher prevalence of each symptom. Those who prefer unhealthier food have higher prevalence of GI symptoms. Conclusions: These data suggest that psycho-behavioral conditions may affect the development of functional GI symptoms regardless of the subtypes of GI symptoms, and may explain the high proportion of overlap in the subtypes. © 2011 Journal of Gastroenterology and Hepatology Foundation and Blackwell Publishing Asia Pty Ltd. Source

Sasaki S.,Tohoku University
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2012

We present the first result for the hyperon vector form factor f 1 for Ξ0→Σ+lν̄ and Σ-→nlν̄ semileptonic decays from fully dynamical lattice QCD. The calculations are carried out with gauge configurations generated by the RBC and UKQCD collaborations with (2+1)-flavors of dynamical domain-wall fermions and the Iwasaki gauge action at β=2.13, corresponding to a cutoff a-1=1.73GeV. Our results, which are calculated at the lighter three sea quark masses (the lightest pion mass down to approximately 330 MeV), show that a sign of the second-order correction of SU(3) breaking on the hyperon vector coupling f1(0) is negative. The tendency of the SU(3)-breaking correction observed in this work disagrees with predictions of both the latest baryon chiral perturbation theory result and large Nc analysis. © 2012 American Physical Society. Source

Sakuma A.,Tohoku University
Journal of the Physical Society of Japan | Year: 2012

We adapt the tight-binding linear muffin-tin orbital (TB-LMTO) method to the torque-correlation model for the Gilbert damping constant α and perform the first-principles calculation for disordered transition metal alloys, Fe-Ni and Fe-Pt systems, within the framework of the CPA. Quantitatively, the calculated α values are about one-half of the experimental values, whereas the variations in the Fermi level dependence of α are much larger than these discrepancies. As expected, we confirm in the (Fe-Ni) 1-XPt X and FePt systems that Pt atoms certainly enhance owing to their large spin-orbit coupling. For the disordered alloys, we find that decreases with increasing chemical degree of order in a wide range. © 2012 The Physical Society of Japan. Source

To determine whether polymorphisms in the Toll-like receptor 4 (TLR4) gene are associated with primary open-angle glaucoma (POAG), normal-tension glaucoma (NTG), and exfoliation glaucoma (XFG) in Japanese individuals. Genetic association study. Setting: Multicenter study. Study population: One hundred eighty-four unrelated Japanese patients with POAG, 365 unrelated patients with NTG, and 109 unrelated patients with XFG from 5 hospitals. Procedures: Genomic DNA was extracted from leukocytes of the peripheral blood, and 8 polymorphisms in the TLR4 genes were amplified by polymerase chain reaction (PCR) and directly sequenced. Allele and genotype frequencies and the inferred haplotypes were estimated. Main outcome measures: Differences in allele and genotype frequencies and haplotypes between subjects with POAG, NTG, and XFG. The allele frequency of rs2149356 of the TLR4 gene in the POAG, NTG, and XFG groups was the most significantly different from that of the control group (minor allele frequency 0.446, 0.395, 0.404, vs 0.308; P = .000058, P = .0030, and P = .015). The allele frequencies of the 5 TLR4 SNPs were higher in all of the glaucoma groups than that in the control group. The statistics of genotypes of TLR4 were approximately the same for all allele frequencies. The haplotypic frequencies with Tag SNPs studied earlier showed that only POAG was statistically significant. Other haplotypes, such as rs10759930, rs1927914, rs1927911, and rs2149356, had higher statistical significance (overall P = .00078 in POAG, overall P = .018 in NTG, and overall P = .014 in XFG). This study demonstrated that TLR4 polymorphisms are associated with NTG in the Japanese, and they also play a role in the pathogenesis of POAG and XFG. Copyright © 2012 Elsevier Inc. All rights reserved. Source

Okura Y.,Japan National Astronomical Observatory | Futamase T.,Tohoku University
Astrophysical Journal | Year: 2013

This is the third paper on the improvement of systematic errors in weak lensing analysis using an elliptical weight function, referred to as E-HOLICs. In previous papers, we succeeded in avoiding errors that depend on the ellipticity of the background image. In this paper, we investigate the systematic error that depends on the signal-to-noise ratio of the background image. We find that the origin of this error is the random count noise that comes from the Poisson noise of sky counts. The random count noise makes additional moments and centroid shift error, and those first-order effects are canceled in averaging, but the second-order effects are not canceled. We derive the formulae that correct this systematic error due to the random count noise in measuring the moments and ellipticity of the background image. The correction formulae obtained are expressed as combinations of complex moments of the image, and thus can correct the systematic errors caused by each object. We test their validity using a simulated image and find that the systematic error becomes less than 1% in the measured ellipticity for objects with an IMCAT significance threshold of ν ∼ 11.7. © 2013. The American Astronomical Society. All rights reserved.. Source

Shintaku H.,Osaka City University | Ohura T.,Tohoku University
Journal of Pediatrics | Year: 2014

Objective To assess the safety and efficacy of tetrahydrobiopterin therapy with sapropterin to treat tetrahydrobiopterin (BH4)-responsive phenylalanine hydroxylase (PAH) deficiency in children aged <4 years compared with those aged ≥4 years. Study design We analyzed a longitudinal follow-up study conducted in all patients with BH4-responsive PAH deficiency throughout Japan. At the end of 2011, 43 patients were receiving sapropterin, of whom 21 were aged <4 years at the initiation of treatment. The starting dose of sapropterin was ≥10 mg/kg/day in 11 of these 21 patients. The duration of follow-up was ≥4 years in 6 of those 11 patients; 3 of these 6 were followed for ≥10 years. Nine patients were receiving sapropterin monotherapy at the end of 2011. Results Serum phenylalanine level was maintained within the recommended optimal control range in all 21 patients who started sapropterin treatment before age 4 years. Only 1 nonserious adverse drug reaction occurred, an elevated alanine aminotransferase level in 1 patient. No significant abnormal behavior related to nerve disorders was reported. Conclusion Sapropterin therapy initiated before age 4 years was effective in maintaining serum phenylalanine level within the favorable range and was safe in Japanese patients with BH4-responsive PAH deficiency. © 2014 Elsevier Inc. All rights reserved. Source

Kato Y.,Tohoku University
Brain Tumor Pathology | Year: 2015

Mutations of isocitrate dehydrogenase 1/2 (IDH1/2) have been reported in gliomas and other types of tumors, such as acute myeloid leukemias, cartilaginous tumors, intrahepatic cholangiocarcinomas, osteosarcomas, and giant cell tumors of bone. In gliomas, IDH mutations uniformly occur in the functionally critical arginine 132 residue (R132) of IDH1 and arginine 172 residue (R172) of IDH2. IDH1 and IDH2 catalyze the oxidative carboxylation of isocitrate to α-ketoglutarate (α-KG) in the cytosol and mitochondria, respectively. In contrast, mutated IDH1/2 proteins possess a neomorphic enzymatic function that changes α-KG into the oncometabolite, R(–)-2-hydroxyglutarate, resulting in genomic hypermethylation, histone methylation, genetic instability, and malignant transformation. To date, several monoclonal antibodies (mAbs) specific for IDH1/2 mutations such as anti-IDH1-R132H mAbs (clone H09, clone IMab-1, and clone HMab-1) or an anti-IDH1-R132S mAb (clone SMab-1) have been established. Furthermore, one of multi-specific mAbs, MsMab-1, recognizes IDH1 mutants (R132H, R132S, R132G) and IDH2 mutants (R172S, R172G), which are observed in gliomas. Another mAb, MsMab-2, recognizes IDH1-R132L and IDH2-R172M. These IDH1/2 mutation-specific mAbs are useful for the immunohistochemical determination of IDH1/2 mutation-bearing gliomas. © 2014, The Japan Society of Brain Tumor Pathology. Source

Wei W.,China Earthquake Administration | Zhao D.,Tohoku University | Xu J.,China Earthquake Administration
Physics of the Earth and Planetary Interiors | Year: 2013

We determined the first 3-D P-wave anisotropy tomography beneath Southeast Tibet and adjacent regions using 63,773 P-wave arrivals from 2866 local earthquakes and 55,457 arrivals from 2802 teleseismic events. A remarkable low-velocity layer with a thickness of about 20. km is revealed in the lower crust, which may reflect a mechanically weak zone capable of flow on a geological timescale. Our seismic anisotropy results suggest that the flow direction changes when it encounters the mechanically strong Sichuan basin. Most of the large earthquakes including the 2008 Wenchuan earthquake (M 8.0) and the 2013 Lushan earthquake (M 7.0) occurred at the margin of the ductile flow in the lower crust, suggesting that the seismogenesis is controlled by the deep dynamic processes. In the upper mantle, the subducting Indian plate is imaged clearly as a high-velocity zone which has reached near the Jinsha River suture. In addition, our results show significant variations of seismic anisotropy with depth, implying that the upper crust and the lithospheric mantle deform separately beneath most parts of the study region. © 2013 Elsevier B.V. Source

Bai Q.,Tohoku University
Optics Express | Year: 2015

Recently, the concept of metasurface has provided one an unprecedented opportunity and ability to control the light in the deep subwavelength scale. However, so far most efforts are devoted to exploiting the novel scattering properties and applications of metasurface in optics. Here, I theoretically and numerically demonstrate that longitudinal and transverse photoinduced voltages can be simultaneously realized in the proposed metasurface utilizing the magnetic resonance under the normal incidence of circularly polarized light, which may extend the concept and functionality of metasurface into the electronics and may provide a potential scheme to realize a nanoscale tunable voltage source through a nanophotonic roadmap. The signs of longitudinal and transverse photoinduced voltages can be manipulated by tuning the resonant frequency and the handedness of circularly polarized light, respectively. Analytical formulae of photoinduced voltage are presented based on the theory of symmetry of field. This work may bridge nanophotonics and electronics, expands the capability of metasurface and has many potential applications. © 2015 Optical Society of America. Source

Mesenchymal cell populations, referred to as mesenchymal stem cells or multipotent stromal cells (MSCs), which include bone marrow stromal cells (BMSCs), umbilical cord stromal cells and adipose stromal cells (ASCs), participate in tissue repair when transplanted into damaged or degenerating tissues. The trophic support and immunomodulation provided by MSCs can protect against tissue damage, and the differentiation potential of these cells may help to replace lost cells. MSCs are easily accessible and can be expanded on a large scale. In addition, BMSCs and ASCs can be harvested from the patient himself. Thus, MSCs are considered promising candidates for cell therapy. In this review, I will discuss recently discovered high-efficiency induction systems for deriving Schwann cells and neurons from MSCs. Other features of MSCs that are important for tissue repair include the self-renewing property of stem cells and their potential for differentiation. Thus, I will also discuss the stemness of MSCs and describe the discovery of a certain stem cell type among adult MSCs that can self-renew and differentiate into cells of all three germ layers. Furthermore, I will explore the prospects of using this cell population for cell therapy. © 2012 Japanese Association of Anatomists. Source

Ishikawa T.,Tohoku University
Journal of Fluid Mechanics | Year: 2012

Microorganisms often swim upwards due to the cell's phototaxis, chemotaxis or geotaxis, in flow fields with vertical velocity gradients. In this study, the vertical dispersion of model microorganisms was investigated under horizontal shear conditions. A microorganism was modelled as a spherical squirmer with or without bottom-heaviness. First, the three-dimensional movement of 100 identical squirmers in a homogeneous suspension was computed by the Stokesian dynamics method. The results show that the dispersion of squirmers is strongly affected by the swimming velocity and bottom-heaviness of the cells and the shear rate of the background flow. The vertical diffusion is considerably smaller than the horizontal diffusion. Interestingly, the vertical diffusion decreases as the volume fraction and the stresslet of squirmers decrease, which is opposite of the tendency in diffusion with no background flow. Next, a continuum model of a suspension of squirmers was developed using the diffusion tensor and the drift velocity to simulate the spatial distribution of squirmers in macroscopic flow fields. The results of the continuum model illustrate that the gyrotactic trapping found by Durham, Kessler & Stocker (Science, vol. 323, 2009, pp. 1067-1070) also appears in the present model considering cell-cell hydrodynamic interactions. In the case of horizontal Poiseuille flow, the volume fraction of bottom-heavy cells in the channel becomes considerably larger than that at the inlet. These fundamental findings are helpful for understanding the distribution of microorganisms in various water regimes in nature and industry. © 2011 Cambridge University Press. Source

Hirano N.,Tohoku University
Geochemical Journal | Year: 2011

One extremely young volcano (0.05-1 Ma) and other young volcanoes (1.8, 4.2, 6.0, and 8.5 Ma) composed of strongly alkaline magma were recently discovered on the abyssal plain of the Early Cretaceous (135 Ma) Pacific Plate. These volcanoes were dubbed "petit-spots". The petit-spot volcanic province represents more than 8 Myr of activity over a large area (∼600 km along the direction of plate motion), but with a relatively small volume of magma production, thus indicating a small supply of heat inconsistent with a hotspot. The low-flux petit-spot volcanoes may be related to the occurrence of a tensional field of lithosphere caused by plate flexure, with the ascending melt derived from a mantle source susceptible to partial melting. Rock samples from the young volcanoes are highly vesicular (up to 60%) despite high hydrostatic pressures at 6000 m water depth, indicating volatile-rich magmas. The depleted heavy rare earth elements and high radiometric isotopic ratios of noble gases indicate the magma was derived from upper mantle. Nevertheless, the low 143Nd/144Nd, high 87Sr/86Sr, low 206Pb/204Pb, and low 207Pb/204Pb ratios are similar to enriched or fertile compositions such as oceanic island basalts. These apparently conflicting data are explained by the extremely small degree of partial melting of recycled materials in the degassing mantle of the asthenosphere, probably with carbonate in the source. The petit-spot volcanoes, therefore, provide a unique window into the nature of the oceanic plate and underlying asthenosphere prior to subduction. Copyright © 2011 by The Geochemical Society of Japan. Source