Showing papers by "Tohoku University published in 2008"
TL;DR: VESTA as mentioned in this paper is a cross-platform program for visualizing both structural and volumetric data in multiple windows with tabs, including isosurfaces, bird's-eye views and two-dimensional maps.
Abstract: A cross-platform program, VESTA, has been developed to visualize both structural and volumetric data in multiple windows with tabs. VESTA represents crystal structures by ball-and-stick, space-filling, polyhedral, wireframe, stick, dot-surface and thermal-ellipsoid models. A variety of crystal-chemical information is extractable from fractional coordinates, occupancies and oxidation states of sites. Volumetric data such as electron and nuclear densities, Patterson functions, and wavefunctions are displayed as isosurfaces, bird's-eye views and two-dimensional maps. Isosurfaces can be colored according to other physical quantities. Translucent isosurfaces and/or slices can be overlapped with a structural model. Collaboration with external programs enables the user to locate bonds and bond angles in the `graphics area', simulate powder diffraction patterns, and calculate site potentials and Madelung energies. Electron densities determined experimentally are convertible into their Laplacians and electronic energy densities.
4,172 citations
TL;DR: It is shown that a specific deficiency of cytotoxic T lymphocyte antigen 4 (CTLA-4) in Tregs results in spontaneous development of systemic lymphoproliferation, fatal T cell–mediated autoimmune disease, and hyperproduction of immunoglobulin E in mice.
Abstract: Naturally occurring Foxp3+CD4+ regulatory T cells (Tregs) are essential for maintaining immunological self-tolerance and immune homeostasis. Here, we show that a specific deficiency of cytotoxic T lymphocyte antigen 4 (CTLA-4) in Tregs results in spontaneous development of systemic lymphoproliferation, fatal T cell-mediated autoimmune disease, and hyperproduction of immunoglobulin E in mice, and it also produces potent tumor immunity. Treg-specific CTLA-4 deficiency impairs in vivo and in vitro suppressive function of Tregs-in particular, Treg-mediated down-regulation of CD80 and CD86 expression on dendritic cells. Thus, natural Tregs may critically require CTLA-4 to suppress immune responses by affecting the potency of antigen-presenting cells to activate other T cells.
2,611 citations
Daniel J. Klionsky1, Hagai Abeliovich2, Patrizia Agostinis3, Devendra K. Agrawal4 +232 more•Institutions (137)
TL;DR: A set of guidelines for the selection and interpretation of the methods that can be used by investigators who are attempting to examine macroautophagy and related processes, as well as by reviewers who need to provide realistic and reasonable critiques of papers that investigate these processes are presented.
Abstract: Research in autophagy continues to accelerate,(1) and as a result many new scientists are entering the field Accordingly, it is important to establish a standard set of criteria for monitoring macroautophagy in different organisms Recent reviews have described the range of assays that have been used for this purpose(2,3) There are many useful and convenient methods that can be used to monitor macroautophagy in yeast, but relatively few in other model systems, and there is much confusion regarding acceptable methods to measure macroautophagy in higher eukaryotes A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers of autophagosomes versus those that measure flux through the autophagy pathway; thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from fully functional autophagy that includes delivery to, and degradation within, lysosomes (in most higher eukaryotes) or the vacuole (in plants and fungi) Here, we present a set of guidelines for the selection and interpretation of the methods that can be used by investigators who are attempting to examine macroautophagy and related processes, as well as by reviewers who need to provide realistic and reasonable critiques of papers that investigate these processes This set of guidelines is not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to verify an autophagic response
2,310 citations
TL;DR: The spin Seebeck effect allows us to pass a pure spin current, a flow of electron spins without electric currents, over a long distance, and is directly applicable to the production of spin-voltage generators, which are crucial for driving spintronic devices.
Abstract: The generation of electric voltage by placing a conductor in a temperature gradient is called the Seebeck effect. Its efficiency is represented by the Seebeck coefficient, S, which is defined as the ratio of the generated electric voltage to the temperature difference, and is determined by the scattering rate and the density of the conduction electrons. The effect can be exploited, for example, in thermal electric-power generators and for temperature sensing, by connecting two conductors with different Seebeck coefficients, a device called a thermocouple. Here we report the observation of the thermal generation of driving power, or voltage, for electron spin: the spin Seebeck effect. Using a recently developed spin-detection technique that involves the spin Hall effect, we measure the spin voltage generated from a temperature gradient in a metallic magnet. This thermally induced spin voltage persists even at distances far from the sample ends, and spins can be extracted from every position on the magnet simply by attaching a metal. The spin Seebeck effect observed here is directly applicable to the production of spin-voltage generators, which are crucial for driving spintronic devices. The spin Seebeck effect allows us to pass a pure spin current, a flow of electron spins without electric currents, over a long distance. These innovative capabilities will invigorate spintronics research.
1,798 citations
TL;DR: In this paper, the authors present guidelines for using computational fluid dynamics (CFD) techniques for predicting pedestrian wind environment around buildings in the design stage, based on cross-comparison between CFD predictions, wind tunnel test results and field measurements.
1,619 citations
TL;DR: The following are described with regard to biomedical applications of titanium alloys: the Young's modulus, wear properties, notch fatigue strength, fatigue behaviour on relation to ageing treatment, and multifunctional deformation behaviours of Titanium alloys.
Abstract: Young's modulus as well as tensile strength, ductility, fatigue life, fretting fatigue life, wear properties, functionalities, etc., should be adjusted to levels that are suitable for structural biomaterials used in implants that replace hard tissue. These factors may be collectively referred to as mechanical biocompatibilities. In this paper, the following are described with regard to biomedical applications of titanium alloys: the Young's modulus, wear properties, notch fatigue strength, fatigue behaviour on relation to ageing treatment, improvement of fatigue strength, fatigue crack propagation resistance and ductility by the deformation-induced martensitic transformation of the unstable beta phase, and multifunctional deformation behaviours of titanium alloys.
1,022 citations
TL;DR: The chiral stationary phase for Heterocycloaddition showed good chiral recognition ability towards various racemates, including N/O-Vinylation/Arylation and Radical Cyclization of Haloalkenes and Haloalkynes.
Abstract: 2.4. Tandem sp-sp Coupling/Cyclization 3418 3. Cycloaddition Reactions 3418 3.1. [3+2] Cycloaddition 3418 3.1.1. Triazole/Isoxazole-Forming Reactions 3418 3.1.2. Reactions of Azomethine Ylides 3419 3.1.3. Cycloaddition of Nitrones 3422 3.1.4. Other [3+2] Reaction 3422 3.2. [4+2] Heterocycloaddition 3422 3.3. [2+2] Cycloaddition 3424 4. Cycloisomerization of Enynes/Diynes 3425 5. Intramolecular Friedel-Crafts-Type Reactions 3428 6. Reactions of R-Diazocarbonyl Compounds 3429 7. Aziridination of Olefins 3431 8. N/O-Vinylation/Arylation 3431 9. Radical Cyclization of Haloalkenes and Haloalkynes 3433
1,014 citations
TL;DR: It is shown that adenosine 5′-triphosphate (ATP) that can be derived from commensal bacteria activates a unique subset of lamina propria cells, CD70highCD11clow cells, leading to the differentiation of TH17 cells, and the critical role of ATP is underscored.
Abstract: Interleukin (IL)-17-producing CD4(+) T lymphocytes (T(H)17 cells) constitute a subset of T-helper cells involved in host defence and several immune disorders. An intriguing feature of T(H)17 cells is their selective and constitutive presence in the intestinal lamina propria. Here we show that adenosine 5'-triphosphate (ATP) that can be derived from commensal bacteria activates a unique subset of lamina propria cells, CD70(high)CD11c(low) cells, leading to the differentiation of T(H)17 cells. Germ-free mice exhibit much lower concentrations of luminal ATP, accompanied by fewer lamina propria T(H)17 cells, compared to specific-pathogen-free mice. Systemic or rectal administration of ATP into these germ-free mice results in a marked increase in the number of lamina propria T(H)17 cells. A CD70(high)CD11c(low) subset of the lamina propria cells expresses T(H)17-prone molecules, such as IL-6, IL-23p19 and transforming-growth-factor-beta-activating integrin-alphaV and -beta8, in response to ATP stimulation, and preferentially induces T(H)17 differentiation of co-cultured naive CD4(+) T cells. The critical role of ATP is further underscored by the observation that administration of ATP exacerbates a T-cell-mediated colitis model with enhanced T(H)17 differentiation. These observations highlight the importance of commensal bacteria and ATP for T(H)17 differentiation in health and disease, and offer an explanation of why T(H)17 cells specifically present in the intestinal lamina propria.
993 citations
TL;DR: It is proposed that the Atg16L complex is a new type of E3-like enzyme that functions as a scaffold for LC3 lipidation by dynamically localizing to the putative source membranes for autophagosome formation.
Abstract: Two ubiquitin-like molecules, Atg12 and LC3/Atg8, are involved in autophagosome biogenesis. Atg12 is conjugated to Atg5 and forms an approximately 800-kDa protein complex with Atg16L (referred to as Atg16L complex). LC3/Atg8 is conjugated to phosphatidylethanolamine and is associated with autophagosome formation, perhaps by enabling membrane elongation. Although the Atg16L complex is required for efficient LC3 lipidation, its role is unknown. Here, we show that overexpression of Atg12 or Atg16L inhibits autophagosome formation. Mechanistically, the site of LC3 lipidation is determined by the membrane localization of the Atg16L complex as well as the interaction of Atg12 with Atg3, the E2 enzyme for the LC3 lipidation process. Forced localization of Atg16L to the plasma membrane enabled ectopic LC3 lipidation at that site. We propose that the Atg16L complex is a new type of E3-like enzyme that functions as a scaffold for LC3 lipidation by dynamically localizing to the putative source membranes for autophagosome formation.
965 citations
TL;DR: Electric-field-induced superconductivity in an insulator is reported by using an electric-double-layer gating in an organic electrolyte using a pristine SrTiO(3) single-crystal channel, indicating this method as promising for searching for unprecedented superconducting states.
Abstract: Increasing the carrier density of a material to the limit at which superconductivity can be induced has been a long-standing challenge. This is now realized in an insulator by using an electric-double-layer gate in an organic electrolyte. Electric field control of charge carrier density has long been a key technology to tune the physical properties of condensed matter, exploring the modern semiconductor industry. One of the big challenges is to increase the maximum attainable carrier density so that we can induce superconductivity in field-effect-transistor geometry. However, such experiments have so far been limited to modulation of the critical temperature in originally conducting samples because of dielectric breakdown1,2,3,4. Here we report electric-field-induced superconductivity in an insulator by using an electric-double-layer gating in an organic electrolyte5. Sheet carrier density was enhanced from zero to 1014 cm−2 by applying a gate voltage of up to 3.5 V to a pristine SrTiO3 single-crystal channel. A two-dimensional superconducting state emerged below a critical temperature of 0.4 K, comparable to the maximum value for chemically doped bulk crystals6, indicating this method as promising for searching for unprecedented superconducting states.
851 citations
TL;DR: Binaphthol-derived monophosphoric acids have been designed as novel chiral Brønsted-acid catalysts, which function as efficient enantioselective catalysts for a variety of organic transformations, especially for carbon-carbon bond forming reactions.
University of Milan1, National and Kapodistrian University of Athens2, Maastricht University3, Tohoku University4, Jichi Medical University5, University of Valencia6, University of Bonn7, University College Dublin8, University of Edinburgh9, University of Padua10, Columbia University11, Complutense University of Madrid12, King's College London13, Semmelweis University14
TL;DR: The main topics addressed include the methodology of home blood pressure monitoring, its diagnostic and therapeutic thresholds, its clinical applications in hypertension, with specific reference to special populations, and its applications in research.
Abstract: This document summarizes the available evidence and provides recommendations on the use of home blood pressure monitoring in clinical practice and in research. It updates the previous recommendations on the same topic issued in year 2000. The main topics addressed include the methodology of home blood pressure monitoring, its diagnostic and therapeutic thresholds, its clinical applications in hypertension, with specific reference to special populations, and its applications in research. The final section deals with the problems related to the implementation of these recommendations in clinical practice.
21 Apr 2008
TL;DR: A general framework for building classifiers that deal with short and sparse text & Web segments by making the most of hidden topics discovered from large-scale data collections that is general enough to be applied to different data domains and genres ranging from Web search results to medical text.
Abstract: This paper presents a general framework for building classifiers that deal with short and sparse text & Web segments by making the most of hidden topics discovered from large-scale data collections. The main motivation of this work is that many classification tasks working with short segments of text & Web, such as search snippets, forum & chat messages, blog & news feeds, product reviews, and book & movie summaries, fail to achieve high accuracy due to the data sparseness. We, therefore, come up with an idea of gaining external knowledge to make the data more related as well as expand the coverage of classifiers to handle future data better. The underlying idea of the framework is that for each classification task, we collect a large-scale external data collection called "universal dataset", and then build a classifier on both a (small) set of labeled training data and a rich set of hidden topics discovered from that data collection. The framework is general enough to be applied to different data domains and genres ranging from Web search results to medical text. We did a careful evaluation on several hundred megabytes of Wikipedia (30M words) and MEDLINE (18M words) with two tasks: "Web search domain disambiguation" and "disease categorization for medical text", and achieved significant quality enhancement.
TL;DR: In this article, a strain sensor was fabricated from a polymer nanocomposite with multiwalled carbon nanotube (MWNT) fillers, and the authors investigated the piezoresistivity of this strain sensor based on an improved three-dimensional (3D) statistical resistor network model incorporating the tunneling effect between the neighboring CNTs, and a fiber reorientation model.
TL;DR: This review summarizes the recent advances in polyamine research in the field of plant science compared with the knowledge obtained in microorganisms and animal systems.
Abstract: Polyamines are low molecular weight, aliphatic polycations found in the cells of all living organisms. Due to their positive charges, polyamines bind to macromolecules such as DNA, RNA, and proteins. They are involved in diverse processes, including regulation of gene expression, translation, cell proliferation, modulation of cell signalling, and membrane stabilization. They also modulate the activities of certain sets of ion channels. Because of these multifaceted functions, the homeostasis of polyamines is crucial and is ensured through regulation of biosynthesis, catabolism, and transport. Through isolation of the genes involved in plant polyamine biosynthesis and loss-of-function experiments on the corresponding genes, their essentiality for growth is reconfirmed. Polyamines are also involved in stress responses and diseases in plants, indicating their importance for plant survival. This review summarizes the recent advances in polyamine research in the field of plant science compared with the knowledge obtained in microorganisms and animal systems.
TL;DR: In this paper, a high-resolution angle-resolved photoelectron spectroscopy study on the Ba0.6K0.4Fe2As2 (Tc=37 K) superconductor was performed, and the isotropic pairing interactions are strongly orbital dependent, as the ratio 2Δ/kBTc switches from weak to strong coupling on different bands.
Abstract: We have performed a high-resolution angle-resolved photoelectron spectroscopy study on the newly discovered superconductor Ba0.6K0.4Fe2As2 (Tc=37 K). We have observed two superconducting gaps with different values: a large gap (Δ~12 meV) on the two small hole-like and electron-like Fermi surface (FS) sheets, and a small gap (~6 meV) on the large hole-like FS. Both gaps, closing simultaneously at the bulk transition temperature (Tc), are nodeless and nearly isotropic around their respective FS sheets. The isotropic pairing interactions are strongly orbital dependent, as the ratio 2Δ/kBTc switches from weak to strong coupling on different bands. The same and surprisingly large superconducting gap due to strong pairing on the two small FSs, which are connected by the (π, 0) spin-density-wave vector in the parent compound, strongly suggests that the pairing mechanism originates from the inter-band interactions between these two nested FS sheets.
Kobe University1, Gifu University2, University of Tokyo3, Ehime University4, Wakayama Medical University5, Lund University6, Osaka University7, Chinese Academy of Sciences8, Tohoku University9, University of Tokushima10, Kyoto Prefectural University of Medicine11, Kyoto University12, Shiga University of Medical Science13, New Generation University College14, Seoul National University15, The Chinese University of Hong Kong16, University of Helsinki17, Kyushu University18, National Cancer Research Institute19
TL;DR: The data implicate KCNQ1 as a diabetes susceptibility gene in groups of different ancestries as well as in two independent Japanese populations, and the risk allele of this polymorphism was associated with impairment of insulin secretion according to the homeostasis model assessment of β-cell function or the corrected insulin response.
Abstract: We carried out a multistage genome-wide association study of type 2 diabetes mellitus in Japanese individuals, with a total of 1,612 cases and 1,424 controls and 100,000 SNPs. The most significant association was obtained with SNPs in KCNQ1, and dense mapping within the gene revealed that rs2237892 in intron 15 showed the lowest P value (6.7 x 10(-13), odds ratio (OR) = 1.49). The association of KCNQ1 with type 2 diabetes was replicated in populations of Korean, Chinese and European ancestry as well as in two independent Japanese populations, and meta-analysis with a total of 19,930 individuals (9,569 cases and 10,361 controls) yielded a P value of 1.7 x 10(-42) (OR = 1.40; 95% CI = 1.34-1.47) for rs2237892. Among control subjects, the risk allele of this polymorphism was associated with impairment of insulin secretion according to the homeostasis model assessment of beta-cell function or the corrected insulin response. Our data thus implicate KCNQ1 as a diabetes susceptibility gene in groups of different ancestries.
TL;DR: In human cancer, somatic mutations occur in the coding region of NRF2, especially among patients with a history of smoking or suffering from squamous cell carcinoma; in the latter case, this leads to poor prognosis.
Abstract: The nuclear factor E2-related factor 2 (Nrf2) is a master transcriptional activator of genes encoding numerous cytoprotective enzymes that are induced in response to environmental and endogenously derived oxidative/electrophilic agents. Under normal, nonstressed circumstances, low cellular concentrations of Nrf2 are maintained by proteasomal degradation through a Keap1-Cul3-Roc1-dependent mechanism. A model for Nrf2 activation has been proposed in which two amino-terminal motifs, DLG and ETGE, promote efficient ubiquitination and rapid turnover; known as the two-site substrate recognition/hinge and latch model. Here, we show that in human cancer, somatic mutations occur in the coding region of NRF2, especially among patients with a history of smoking or suffering from squamous cell carcinoma; in the latter case, this leads to poor prognosis. These mutations specifically alter amino acids in the DLG or ETGE motifs, resulting in aberrant cellular accumulation of Nrf2. Mutant Nrf2 cells display constitutive induction of cytoprotective enzymes and drug efflux pumps, which are insensitive to Keap1-mediated regulation. Suppression of Nrf2 protein levels by siRNA knockdown sensitized cancer cells to oxidative stress and chemotherapeutic reagents. Our results strongly support the contention that constitutive Nrf2 activation affords cancer cells with undue protection from their inherently stressed microenvironment and anti-cancer treatments. Hence, inactivation of the Nrf2 pathway may represent a therapeutic strategy to reinforce current treatments for malignancy. Congruously, the present study also provides in vivo validation of the two-site substrate recognition model for Nrf2 activation by the Keap1-Cul3-based E3 ligase.
TL;DR: In this article, the luminosity functions (LFs) and various properties of Lyα emitters (LAEs) at z = 3.1, 3.7, and 5.7 in a 1 deg2 sky of the Subaru/XMM-Newton Deep Survey (SXDS) Field were presented.
Abstract: We present luminosity functions (LFs) and various properties of Lyα emitters (LAEs) at z = 3.1, 3.7, and 5.7, in a 1 deg2 sky of the Subaru/XMM–Newton Deep Survey (SXDS) Field. We obtain a photometric sample of 858 LAE candidates based on deep Subaru Suprime-Cam imaging data and a spectroscopic sample of 84 confirmed LAEs from Subaru FOCAS and VLT VIMOS spectroscopy in a survey volume of ~106 Mpc3 with a limiting Lyα luminosity of ~3 × 1042 ergs s−1. We derive the LFs of the Lyα and UV continuum (1500 A) for each redshift, taking into account the statistical error and the field-to-field variation. We find that the apparent Lyα LF shows no significant evolution between z = 3.1 and 5.7 within factors of 1.8 and 2.7 in L* and *, respectively. On the other hand, the UV LF of LAEs increases from z = 3.1 to 5.7, indicating that galaxies with Lyα emission are more common at earlier epochs. We identify six LAEs with AGN activities from our spectra combined with VLA, Spitzer, and XMM-Newton data. Among the photometrically selected LAEs at z = 3.1 and 3.7, only 1% show AGN activities, while the brightest LAEs with log L(Ly α) 43.4–43.6 ergs s−1 appear to always host AGNs. Our LAEs are bluer in UV-continuum color than dropout galaxies, suggesting lower extinction and/or younger stellar populations. Our stacking analyses provide upper limits to the radio luminosity and the fHe II/fLyα line fraction and constrain the hidden star formation (+low-luminosity AGN) and the primordial population in LAEs.
TL;DR: Long-awaited experimental evidence for a curved one-dimensional chain for lithium motion is provided by combining high-temperature powder neutron diffraction and the maximum entropy method, lithium distribution along the [010] direction was clearly visualized.
Abstract: Chemical energy storage using batteries will become increasingly important for future environmentally friendly ('green') societies. The lithium-ion battery is the most advanced energy storage system, but its application has been limited to portable electronics devices owing to cost and safety issues. State-of-the-art LiFePO4 technology as a new cathode material with surprisingly high charge-discharge rate capability has opened the door for large-scale application of lithium-ion batteries such as in plug-in hybrid vehicles. The scientific community has raised the important question of why a facile redox reaction is possible in the insulating material. Geometric information on lithium diffusion is essential to understand the facile electrode reaction of LixFePO4 (0
TL;DR: A DNA-based Ag(i) sensor was developed that employed an oligodeoxyribonucleotide containing C-C pairs used for Ag( i) binding sites that unexpectedly stabilized DNA duplexes containing the naturally occurring cytosine-cytosine (C-C) mismatch-base pair.
TL;DR: It is demonstrated in vivo that TANK-binding kinase 1 (TBK1), a non-canonical IκB kinase, mediates the adjuvant effect of DNA vaccines and is essential for its immunogenicity in mice.
Abstract: Successful vaccines contain not only protective antigen(s) but also an adjuvant component that triggers innate immune activation and is necessary for their optimal immunogenicity. In the case of DNA vaccines, this consists of plasmid DNA; however, the adjuvant element(s) as well as its intra- and inter-cellular innate immune signalling pathway(s) leading to the encoded antigen-specific T- and B-cell responses remain unclear. Here we demonstrate in vivo that TANK-binding kinase 1 (TBK1), a non-canonical IkappaB kinase, mediates the adjuvant effect of DNA vaccines and is essential for its immunogenicity in mice. Plasmid-DNA-activated, TBK1-dependent signalling and the resultant type-I interferon receptor-mediated signalling was required for induction of antigen-specific B and T cells, which occurred even in the absence of innate immune signalling through a well known CpG DNA sensor-Toll-like receptor 9 (TLR9) or Z-DNA binding protein 1 (ZBP1, also known as DAI, which was recently reported as a potential B-form DNA sensor). Moreover, bone-marrow-transfer experiments revealed that TBK1-mediated signalling in haematopoietic cells was critical for the induction of antigen-specific B and CD4(+) T cells, whereas in non-haematopoietic cells TBK1 was required for CD8(+) T-cell induction. These data suggest that TBK1 is a key signalling molecule for DNA-vaccine-induced immunogenicity, by differentially controlling DNA-activated innate immune signalling through haematopoietic and non-haematopoietic cells.
TL;DR: It is shown that the manipulation of magnetization can be achieved solely by electric fields in a ferromagnetic semiconductor, (Ga,Mn)As, allowing manipulation of the magnetization direction.
Abstract: Conventional semiconductor devices use electric fields to control conductivity, a scalar quantity, for information processing. In magnetic materials, the direction of magnetization, a vector quantity, is of fundamental importance. In magnetic data storage, magnetization is manipulated with a current-generated magnetic field (Oersted-Ampere field), and spin current is being studied for use in non-volatile magnetic memories. To make control of magnetization fully compatible with semiconductor devices, it is highly desirable to control magnetization using electric fields. Conventionally, this is achieved by means of magnetostriction produced by mechanically generated strain through the use of piezoelectricity. Multiferroics have been widely studied in an alternative approach where ferroelectricity is combined with ferromagnetism. Magnetic-field control of electric polarization has been reported in these multiferroics using the magnetoelectric effect, but the inverse effect-direct electrical control of magnetization-has not so far been observed. Here we show that the manipulation of magnetization can be achieved solely by electric fields in a ferromagnetic semiconductor, (Ga,Mn)As. The magnetic anisotropy, which determines the magnetization direction, depends on the charge carrier (hole) concentration in (Ga,Mn)As. By applying an electric field using a metal-insulator-semiconductor structure, the hole concentration and, thereby, the magnetic anisotropy can be controlled, allowing manipulation of the magnetization direction.
TL;DR: Using the spin Hall effect, magnetization relaxation in a Ni_{81}Fe_{19}/Pt film is manipulated electrically without applying electric currents directly to the magnetic layer.
Abstract: Using the spin Hall effect, magnetization relaxation in a Ni_{81}Fe_{19}/Pt film is manipulated electrically. An electric current applied to the Pt layer exerts spin torque on the entire magnetization of the Ni81Fe19 layer via the macroscopic spin transfer induced by the spin Hall effect and modulates the magnetization relaxation in the Ni81Fe19 layer. This method allows us to tune the magnetization dynamics regardless of the film size without applying electric currents directly to the magnetic layer.
TL;DR: In this article, the superconducting phase diagram of NdFeAsO 1- y was established as a function of oxygen content, which was determined by Rietveld refinement.
Abstract: The crystal structure of LnFeAsO 1- y (Ln = La, Nd) has been studied by the powder neutron diffraction technique. The superconducting phase diagram of NdFeAsO 1- y is established as a function of oxygen content which is determined by Rietveld refinement. The small As–Fe bond length suggests that As and Fe atoms are connected covalently. FeAs 4 -tetrahedrons transform toward a regular shape with increasing oxygen deficiency. Superconducting transition temperatures seem to attain maximum values for regular FeAs 4 -tetrahedrons.
TL;DR: In this paper, the authors derived big-bang nucleosynthesis (BBN) constraints on both unstable and stable gravitino taking account of recent progress in theoretical study of the BBN processes as well as observations of primordial light-element abundances.
Abstract: We derive big-bang nucleosynthesis (BBN) constraints on both unstable and stable gravitino taking account of recent progress in theoretical study of the BBN processes as well as observations of primordial light-element abundances In the case of unstable gravitino, we set the upper limit on the reheating temperature assuming that the primordial gravitinos are mainly produced by the scattering processes of thermal particles For stable gravitino, we consider B-ino, stau, and sneutrino as the next-to-the-lightest supersymmetric particle and obtain constraints on their properties Compared with the previous works, we improved the following points: (i) we use the most recent observational data, (ii) for gravitino production, we include contribution of the longitudinal component, and (iii) for the case with unstable long-lived stau, we estimate the bound-state effect of stau accurately by solving the Boltzmann equation
TL;DR: Experimental characterization of shear transformation zones (STZs) for plastic flow of bulk metallic glasses (BMGs) based on a newly developed cooperative shearing model provides compelling evidence that the plastic Flow of metallic glasses occurs through Cooperative shearing of unstable STZs activated by shear stresses.
Abstract: We report experimental characterization of shear transformation zones (STZs) for plastic flow of bulk metallic glasses (BMGs) based on a newly developed cooperative shearing model [Johnson WL, Samwer K (2005) A universal criterion for plastic yielding of metallic glasses with a (T/Tg)2/3 temperature dependence. Phys Rev Lett 95: 195501]. The good agreement between experimental measurements and theoretical predictions in the STZ volumes provides compelling evidence that the plastic flow of metallic glasses occurs through cooperative shearing of unstable STZs activated by shear stresses. Moreover, the ductility of BMGs was found to intrinsically correlate with their STZ volumes. The experiments presented herein pave a way to gain a quantitative insight into the atomic-scale mechanisms of BMG mechanical behavior.
TL;DR: In this article, the authors derived the relativistic second-order resonance condition for a whistler-mode wave with a varying frequency and found that the seeds of chorus emissions with a rising frequency are generated near the magnetic equator as a result of a nonlinear growth mechanism that depends on the wave amplitude.
Abstract: [1] The generation process of whistler-mode chorus emissions is analyzed by both theory and simulation. Driven by an assumed strong temperature anisotropy of energetic electrons, the initial wave growth of chorus is linear. After the linear growth phase, the wave amplitude grows nonlinearly. It is found that the seeds of chorus emissions with rising frequency are generated near the magnetic equator as a result of a nonlinear growth mechanism that depends on the wave amplitude. We derive the relativistic second-order resonance condition for a whistler-mode wave with a varying frequency. Wave trapping of resonant electrons near the equator results in the formation of an electromagnetic electron hole in the wave phase space. For a specific wave phase variation, corresponding to a rising frequency, the electron hole can form a resonant current that causes growth of a wave with a rising frequency. Seeds of chorus elements grow from the saturation level of the whistler-mode instability at the equator and then propagate away from the equator. In the frame of reference moving with the group velocity, the wave frequency is constant. The wave amplitude is amplified by the nonlinear resonant current, which is sustained by the increasing inhomogeneity of the dipole magnetic field over some distance from the equator. Chorus elements are generated successively at the equator so long as a sufficient flux of energetic electrons with a strong temperature anisotropy is present.
TL;DR: An extension of the caries ecological hypothesis is proposed to explain the relation between dynamic changes in the phenotypic/genotypic properties of plaque bacteria and the demineralization/remineralization balance of the Caries process.
Abstract: In this essay we propose an extension of the caries ecological hypothesis to explain the relation between dynamic changes in the phenotypic/genotypic properties of plaque bacteria and the demineraliza
TL;DR: Critical roles of the cysteine residues in vivo in maintaining Keap1 function are demonstrated, such that Nrf2 is repressed under quiescent conditions and active in response to oxidants/electrophiles.
Abstract: Keap1 and Cul3 constitute a unique ubiquitin E3 ligase that degrades Nrf2, a key activator of cytoprotective genes. Upon exposure to oxidants/electrophiles, the enzymatic activity of this ligase complex is inhibited and the complex fails to degrade Nrf2, resulting in the transcriptional activation of Nrf2 target genes. Keap1 possesses several reactive cysteine residues that covalently bond with electrophiles in vitro. To clarify the functional significance of each Keap1 cysteine residue under physiological conditions, we established a transgenic complementation rescue model. The transgenic expression of mutant Keap1(C273A) and/or Keap1(C288A) protein in Keap1 null mice failed to reverse constitutive Nrf2 activation, indicating that cysteine residues at positions 273 and 288 are essential for Keap1 to repress Nrf2 activity in vivo. In contrast, Keap1(C151S) retained repressor activity and mice expressing this molecule were viable. Mouse embryonic fibroblasts from Keap1(C151S) transgenic mice displayed decreased expression of Nrf2 target genes both before and after an electrophilic challenge, suggesting that Cys151 is important in facilitating Nrf2 activation. These results demonstrate critical roles of the cysteine residues in vivo in maintaining Keap1 function, such that Nrf2 is repressed under quiescent conditions and active in response to oxidants/electrophiles.