Showing papers by "Tokyo University of Science published in 2014"

Negative electrodes for Na-ion batteries.

Abstract: Research interest in Na-ion batteries has increased rapidly because of the environmental friendliness of sodium compared to lithium. Throughout this Perspective paper, we report and review recent scientific advances in the field of negative electrode materials used for Na-ion batteries. This paper sheds light on negative electrode materials for Na-ion batteries: carbonaceous materials, oxides/phosphates (as sodium insertion materials), sodium alloy/compounds and so on. These electrode materials have different reaction mechanisms for electrochemical sodiation/desodiation processes. Moreover, not only sodiation-active materials but also binders, current collectors, electrolytes and electrode/electrolyte interphase and its stabilization are essential for long cycle life Na-ion batteries. This paper also addresses the prospect of Na-ion batteries as low-cost and long-life batteries with relatively high-energy density as their potential competitive edge over the commercialized Li-ion batteries.

Bio-Inspired Titanium Dioxide Materials with Special Wettability and Their Applications

Abstract: Their Applications Kesong Liu,†,∥ Moyuan Cao,† Akira Fujishima, and Lei Jiang*,†,‡ †Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry and Environment, Beihang University, Beijing 100191, PR China ‡Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, PR China Research Institute for Science and Technology, Photocatalysis International Research Center, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo 162-8601, Japan Institute for Superconducting and Electronic Materials, University of Wollongong, Innovation Campus, Squires Way, North Wollongong, NSW 2500, Australia

The Physics of the B Factories

Abstract: This work is on the Physics of the B Factories. Part A of this book contains a brief description of the SLAC and KEK B Factories as well as their detectors, BaBar and Belle, and data taking related issues. Part B discusses tools and methods used by the experiments in order to obtain results. The results themselves can be found in Part C.

Indications of intermediate-scale anisotropy of cosmic rays with energy greater than 57 EeV in the northern sky measured with the surface detector of the Telescope Array experiment

Abstract: We have searched for intermediate-scale anisotropy in the arrival directions of ultrahigh-energy cosmic rays with energies above 57 EeV in the northern sky using data collected over a 5 yr period by the surface detector of the Telescope Array experiment. We report on a cluster of events that we call the hotspot, found by oversampling using 20° radius circles. The hotspot has a Li-Ma statistical significance of 5.1σ, and is centered at R.A. = 146.°7, decl. = 43.°2. The position of the hotspot is about 19° off of the supergalactic plane. The probability of a cluster of events of 5.1σ significance, appearing by chance in an isotropic cosmic-ray sky, is estimated to be 3.7 × 10-4 (3.4σ). © 2014. The American Astronomical Society. All rights reserved.

High-yield electrochemical production of formaldehyde from CO2 and seawater.

Abstract: The catalytic, electrocatalytic, or photocatalytic conversion of CO2 into useful chemicals in high yield for industrial applications has so far proven difficult. Herein, we present our work on the electrochemical reduction of CO2 in seawater using a boron-doped diamond (BDD) electrode under ambient conditions to produce formaldehyde. This method overcomes the usual limitation of the low yield of higher-order products, and also reduces the generation of H2 . In comparison with other electrode materials, BDD electrodes have a wide potential window and high electrochemical stability, and, moreover, exhibit very high Faradaic efficiency (74%) for the production of formaldehyde, using either methanol, aqueous NaCl, or seawater as the electrolyte. The high Faradaic efficiency is attributed to the sp(3)-bonded carbon of the BDD. Our results have wide ranging implications for the efficient and cost-effective conversion of CO2.

New O2/P2‐type Li‐Excess Layered Manganese Oxides as Promising Multi‐Functional Electrode Materials for Rechargeable Li/Na Batteries

Abstract: A new and promising P2-type layered oxide, Na5/6[Li1/4Mn3/4]O2 is prepared using a solid-state method. Detailed crystal structures of the sample are analyzed by synchrotron X-ray diffraction combined with high-resolution neutron diffraction. P2-type Na5/6[Li1/4Mn3/4]O2 consists of two MeO2 layers with partial in-plane √3a × √3a-type Li/Mn ordering. Na/Li ion-exchange in a molten salt results in a phase transition accompanied with glide of [Li1/4Mn3/4]O2 layers without the destruction of in-plane cation ordering. P2-type Na5/6[Li1/4Mn3/4]O2 translates into an O2-type layered structure with staking faults as the result of ion-exchange. Electrode performance of P2-type Na5/6[Li1/4Mn3/4]O2 and O2-type Lix[Li1/4Mn3/4]O2 is examined and compared in Na and Li cells, respectively. Both samples show large reversible capacity, ca. 200 mA h g−1, after charge to high voltage regardless of the difference in charge carriers. Structural analysis suggests that in-plane structural rearrangements, presumably associated with partial oxygen loss, occur in both samples after charge to a high-voltage region. Such structural activation process significantly influences electrode performance of the P2/O2-type phases, similar to O3-type Li2MnO3-based materials. Crystal structures, phase-transition mechanisms, and the possibility of the P2/O2-type phases as high-capacity and long-cycle-life electrode materials with the multi-functionality for both rechargeable Li/Na batteries are discussed in detail.

Superhydrophobic Surfaces Developed by Mimicking Hierarchical Surface Morphology of Lotus Leaf

Abstract: The lotus plant is recognized as a 'King plant' among all the natural water repellent plants due to its excellent non-wettability The superhydrophobic surfaces exhibiting the famous 'Lotus Effect', along with extremely high water contact angle (>150°) and low sliding angle (<10°), have been broadly investigated and extensively applied on variety of substrates for potential self-cleaning and anti-corrosive applications Since 1997, especially after the exploration of the surface micro/nanostructure and chemical composition of the lotus leaves by the two German botanists Barthlott and Neinhuis, many kinds of superhydrophobic surfaces mimicking the lotus leaf-like structure have been widely reported in the literature This review article briefly describes the different wetting properties of the natural superhydrophobic lotus leaves and also provides a comprehensive state-of-the-art discussion on the extensive research carried out in the field of artificial superhydrophobic surfaces which are developed by mimicking the lotus leaf-like dual scale micro/nanostructure This review article could be beneficial for both novice researchers in this area as well as the scientists who are currently working on non-wettable, superhydrophobic surfaces

A new electrode material for rechargeable sodium batteries: P2-type Na2/3[Mg0.28Mn0.72]O2 with anomalously high reversible capacity

Abstract: P2-type Na2/3[Mg0.28Mn0.72]O2 is prepared and electrode performance in Na cells is first provided. The sample surprisingly delivers a large reversible capacity (220 mA h g−1) even though electrochemically inactive magnesium ions are enriched in the host structure. This new electrode material is potentially utilized for rechargeable batteries made from only earth-abundant elements.

Confirmatory double-blind, parallel-group, placebo-controlled study of efficacy and safety of edaravone (MCI-186) in amyotrophic lateral sclerosis patients

Abstract: Our objective was to confirm the efficacy and safety of edaravone in amyotrophic lateral sclerosis (ALS) patients. We conducted a 36-week confirmatory study, consisting of 12-week pre-observation p...

Bioactive nanoparticles stimulate bone tissue formation in bioprinted three‐dimensional scaffold and human mesenchymal stem cells

Abstract: Bioprinting based on thermal inkjet printing is a promising but unexplored approach in bone tissue engineering. Appropriate cell types and suitable biomaterial scaffolds are two critical factors to generate successful bioprinted tissue. This study was undertaken in order to evaluate bioactive ceramic nanoparticles in stimulating osteogenesis of printed bone marrow-derived human mesenchymal stem cells (hMSCs) in poly(ethylene glycol)dimethacrylate (PEGDMA) scaffold. hMSCs suspended in PEGDMA were co-printed with nanoparticles of bioactive glass (BG) and hydroxyapatite (HA) under simultaneous polymerization so the printed substrates were delivered with highly accurate placement in three-dimensional (3D) locations. hMSCs interacted with HA showed the highest cell viability (86.62 ± 6.02%) and increased compressive modulus (358.91 ± 48.05 kPa) after 21 days in culture among all groups. Biochemical analysis showed the most collagen production and highest alkaline phosphatase activity in PEG-HA group, which is consistent with gene expression determined by quantitative PCR. Masson's trichrome staining also showed the most collagen deposition in PEG-HA scaffold. Therefore, HA is more effective comparing to BG for hMSCs osteogenesis in bioprinted bone constructs. Combining with our previous experience in vasculature, cartilage, and muscle bioprinting, this technology demonstrates the capacity for both soft and hard tissue engineering with biomimetic structures.

Basophils Promote Innate Lymphoid Cell Responses in Inflamed Skin

Abstract: Type 2 inflammation underlies allergic diseases such as atopic dermatitis, which is characterized by the accumulation of basophils and group 2 innate lymphoid cells (ILC2s) in inflamed skin lesions Although murine studies have demonstrated that cutaneous basophil and ILC2 responses are dependent on thymic stromal lymphopoietin, whether these cell populations interact to regulate the development of cutaneous type 2 inflammation is poorly defined In this study, we identify that basophils and ILC2s significantly accumulate in inflamed human and murine skin and form clusters not observed in control skin We demonstrate that murine basophil responses precede ILC2 responses and that basophils are the dominant IL-4-enhanced GFP-expressing cell type in inflamed skin Furthermore, basophils and IL-4 were necessary for the optimal accumulation of ILC2s and induction of atopic dermatitis-like disease We show that ILC2s express IL-4Rα and proliferate in an IL-4-dependent manner Additionally, basophil-derived IL-4 was required for cutaneous ILC2 responses in vivo and directly regulated ILC2 proliferation ex vivo Collectively, these data reveal a previously unrecognized role for basophil-derived IL-4 in promoting ILC2 responses during cutaneous inflammation

BiVO4–Ru/SrTiO3:Rh composite Z-scheme photocatalyst for solar water splitting

Abstract: BiVO4–SrTiO3:Rh composites in which the Rh-doped SrTiO3 particles of a H2-evolving photocatalyst attached on the BiVO4 particles of an O2-evolving photocatalyst were prepared by an impregnation method and a liquid–solid state reaction. The composites showed photocatalytic activity for Z-schematic water splitting under visible light or simulated sunlight irradiation without an electron mediator. The optimum pH for the water splitting was neutral. Water splitting over the composite proceeded via an interparticle electron transfer from BiVO4 to Ru/SrTiO3:Rh particles at the large interfacial area obtained by those preparation methods. The photocatalytic water splitting activity of the composite depended on the crystallinity and morphology of BiVO4. The composite prepared by the liquid–solid state reaction showed the highest photocatalytic activity. This was due to the formation of well-crystallized BiVO4 single-crystal-like particles. The BiVO4–Ru/SrTiO3:Rh composite photocatalyst gave a quantum yield of 1.6% at 420 nm and a stable activity. Thus, we have developed the simplest system requiring no additives, except for photocatalyst powder and water, for photocatalytic solar water splitting.

Exposure to food allergens through inflamed skin promotes intestinal food allergy through the thymic stromal lymphopoietin-basophil axis.

Abstract: Background Exposure to food allergens through a disrupted skin barrier has been recognized as a potential factor in the increasing prevalence of food allergy. Objective We sought to test the immunologic mechanisms by which epicutaneous sensitization to food allergens predisposes to intestinal food allergy. Methods Mice were epicutaneously sensitized with ovalbumin or peanut on an atopic dermatitis–like skin lesion, followed by intragastric antigen challenge. Antigen-specific serum IgE levels and T H 2 cytokine responses were measured by ELISA. Expression of type 2 cytokines and mast cell proteases in the intestine were measured by using real-time PCR. Accumulation of basophils in the skin and mast cells in the intestine was examined by using flow cytometry. In vivo basophil depletion was achieved by using diphtheria toxin treatment of Baso-DTR mice. For cell-transfer studies, the basophil population was expanded in vivo by means of hydrodynamic tail vein injection of thymic stromal lymphopoietin (TSLP) cDNA plasmid. Results Sensitization to food allergens through an atopic dermatitis–like skin lesion is associated with an expansion of TSLP-elicited basophils in the skin that promote antigen-specific T H 2 cytokine responses, increased antigen-specific serum IgE levels, and accumulation of mast cells in the intestine, promoting the development of intestinal food allergy. Critically, disruption of TSLP responses or depletion of basophils reduced the susceptibility to intestinal food allergy, whereas transfer of TSLP-elicited basophils into intact skin promoted disease. Conclusion Epicutaneous sensitization on a disrupted skin barrier is associated with accumulation of TSLP-elicited basophils, which are necessary and sufficient to promote antigen-induced intestinal food allergy.

Ca2+-Activated Reactive Oxygen Species Production by Arabidopsis RbohH and RbohJ Is Essential for Proper Pollen Tube Tip Growth

Abstract: In flowering plants, pollen germinates on the stigma and pollen tubes grow through the style to fertilize the ovules. Enzymatic production of reactive oxygen species (ROS) has been suggested to be involved in pollen tube tip growth. Here, we characterized the function and regulation of the NADPH oxidases RbohH and RbohJ (Respiratory burst oxidase homolog H and J) in pollen tubes in Arabidopsis thaliana. In the rbohH and rbohJ single mutants, pollen tube tip growth was comparable to that of the wild type; however, tip growth was severely impaired in the double mutant. In vivo imaging showed that ROS accumulation in the pollen tube was impaired in the double mutant. Both RbohH and RbohJ, which contain Ca2+ binding EF-hand motifs, possessed Ca2+-induced ROS-producing activity and localized at the plasma membrane of the pollen tube tip. Point mutations in the EF-hand motifs impaired Ca2+-induced ROS production and complementation of the double mutant phenotype. We also showed that a protein phosphatase inhibitor enhanced the Ca2+-induced ROS-producing activity of RbohH and RbohJ, suggesting their synergistic activation by protein phosphorylation and Ca2+. Our results suggest that ROS production by RbohH and RbohJ is essential for proper pollen tube tip growth, and furthermore, that Ca2+-induced ROS positive feedback regulation is conserved in the polarized cell growth to shape the long tubular cell.

Thermodynamic and kinetic analysis of heterogeneous photocatalysis for semiconductor systems.

Abstract: Since the report of the Honda–Fujishima effect, heterogeneous photocatalysis has attracted much attention around the world because of its potential energy and environmental applications. Although great progresses have been made in recent years, most were focused on preparing highly-active photocatalysts and investigating visible light utilization. In fact, we are still unclear on the thermodynamic and kinetic nature of photocatalysis to date, which sometimes leads to misunderstandings for experimental results. It is timely to give a review and discussion on the thermodynamics and kinetics of photocatalysis, so as to direct future researches. However, there is an absence of a detailed review on this topic until now. In this article, we tried to review and discuss the thermodynamics and kinetics of photocatalysis. We explained the thermodynamic driving force of photocatalysis, and distinguished the functions of light and heat in photocatalysis. The Langmuir–Hinshelwood kinetic model, the ˙OH oxidation mechanism, and the direct–indirect (D–I) kinetic model were reviewed and compared. Some applications of the D–I model to study photocatalytic kinetics were also discussed. The electron transport mode and its importance in photocatalysis were investigated. Finally, the intrinsic relation between the kinetics and the thermodynamics of photocatalytic reactions was discussed.

Layered oxides as positive electrode materials for Na-ion batteries

Abstract: Considering the need for designing better batteries to meet the rapidly growing demand for large-scale energy storage applications, an aspect of primary importance for battery materials is elemental abundance. To achieve sustainable energy development, we must reconsider the feasibility of a sustainable lithium supply, which is essential for lithium(-ion) batteries. Lithium is widely distributed in the Earth, but is not regarded as an abundant element. Therefore, widespread use of large-scale lithium batteries would be inevitably restricted. Sodium(-ion) batteries are thus promising candidates for large-scale applications because sodium is the most advantageous next to lithium considering its atomic weight, standard potential, and natural abundance. Rechargeable sodium-ion batteries consist of two different sodium insertion materials similar to Li-ion batteries. Sodium insertion materials, especially layered oxides, have been studied since the early 1980s, but not extensively for energy storage devices due to the expanded interest in lithium insertion materials in the 1990s. In recent years, materials researchers have again been extensively exploring new sodium insertion materials to enhance battery performance. This article reviews recent advancements and trends in layered sodium transition metal oxides as positive electrode materials for Na-ion batteries.

Phosphorus Electrodes in Sodium Cells: Small Volume Expansion by Sodiation and the Surface-Stabilization Mechanism in Aprotic Solvent

Abstract: The electrode performance of amorphous phosphorus in aprotic Na cells is examined. Amorphous phosphorus is electrochemically reduced in the Na cells with a three-electron redox process, crystallizing into Na3P. NaP bonds in Na3P have high covalent characteristics. Therefore, the molar volume of Na in Na3P is anomalously small in comparison to other Na–metal alloys that have been used as negative electrode materials. The theoretical volumetric capacity, calculated at full volume expansion of amorphous phosphorus electrodes through sodiation, is expected to be 27 % larger than that of metallic sodium. However, experimentally, it is found that severe electrolyte decomposition results in insufficient reversibility of the electrode materials, owing to the highly reactive Na3P surface. Electrode reversibility is successfully improved by utilizing an electrolyte additive, fluoroethylene carbonate (FEC). The surface chemistry of phosphorus in the aprotic solvent with sodium salts is examined by hard/soft X-ray photoelectron spectroscopy (PES). PES studies reveal that FEC effectively stabilizes the solid–electrolyte interphase (SEI), containing monovalent phosphorus species and sodium fluoride, and thus electrolyte decomposition is partly suppressed by the relatively stable SEI formed on the surface of phosphorus particles.

Giant Seebeck coefficient in semiconducting single-wall carbon nanotube film

Abstract: We found a giant Seebeck effect in semiconducting single-wall carbon nanotube (SWCNT) films, which exhibited a performance comparable to that of commercial Bi2Te3 alloys. Carrier doping of semiconducting SWCNT films further improved the thermoelectric performance. These results were reproduced well by first-principles transport simulations based on a simple SWCNT junction model. These findings suggest strategies that pave the way for emerging printed, all-carbon, flexible thermoelectric devices.

Carrier-envelope phase-dependent high harmonic generation in the water window using few-cycle infrared pulses

Abstract: The higher-harmonic generation of laser pulses is used to achieve short-wavelength attosecond pulses for ultrashort experiments, but has been limited in the achievable energy. Here, Ishii et al. develop a scheme to break this barrier and to achieve photon energies higher than the carbon K edge of about 284 eV.

Perivascular leukocyte clusters are essential for efficient activation of effector T cells in the skin

Abstract: It remains largely unclear how antigen-presenting cells (APCs) encounter effector or memory T cells efficiently in the periphery. Here we used a mouse contact hypersensitivity (CHS) model to show that upon epicutaneous antigen challenge, dendritic cells (DCs) formed clusters with effector T cells in dermal perivascular areas to promote in situ proliferation and activation of skin T cells in a manner dependent on antigen and the integrin LFA-1. We found that DCs accumulated in perivascular areas and that DC clustering was abrogated by depletion of macrophages. Treatment with interleukin 1α (IL-1α) induced production of the chemokine CXCL2 by dermal macrophages, and DC clustering was suppressed by blockade of either the receptor for IL-1 (IL-1R) or the receptor for CXCL2 (CXCR2). Our findings suggest that the dermal leukocyte cluster is an essential structure for elicitating acquired cutaneous immunity.

Giant Seebeck coefficient in semiconducting single-wall carbon nanotube film

Abstract: We found a giant Seebeck effect in semiconducting single-wall carbon nanotube (SWCNT) films, which exhibited a performance comparable to that of commercial Bi2Te3 alloys. Carrier doping of semiconducting SWCNT films further improved the thermoelectric performance. These results were reproduced well by first-principles transport simulations based on a simple SWCNT junction model. These findings suggest strategies that pave the way for emerging printed, all-carbon, flexible thermoelectric devices.

A source of antihydrogen for in-flight hyperfine spectroscopy

Abstract: Antihydrogen, a positron bound to an antiproton, is the simplest antiatom. Its counterpart-hydrogen--is one of the most precisely investigated and best understood systems in physics research. High-resolution comparisons of both systems provide sensitive tests of CPT symmetry, which is the most fundamental symmetry in the Standard Model of elementary particle physics. Any measured difference would point to CPT violation and thus to new physics. Here we report the development of an antihydrogen source using a cusp trap for in-flight spectroscopy. A total of 80 antihydrogen atoms are unambiguously detected 2.7 m downstream of the production region, where perturbing residual magnetic fields are small. This is a major step towards precision spectroscopy of the ground-state hyperfine splitting of antihydrogen using Rabi-like beam spectroscopy.

Recognition of tumor cells by Dectin-1 orchestrates innate immune cells for anti-tumor responses

Abstract: The eradication of tumor cells requires communication to and signaling by cells of the immune system. Natural killer (NK) cells are essential tumor-killing effector cells of the innate immune system; however, little is known about whether or how other immune cells recognize tumor cells to assist NK cells. Here, we show that the innate immune receptor Dectin-1 expressed on dendritic cells and macrophages is critical to NK-mediated killing of tumor cells that express N-glycan structures at high levels. Receptor recognition of these tumor cells causes the activation of the IRF5 transcription factor and downstream gene induction for the full-blown tumoricidal activity of NK cells. Consistent with this, we show exacerbated in vivo tumor growth in mice genetically deficient in either Dectin-1 or IRF5. The critical contribution of Dectin-1 in the recognition of and signaling by tumor cells may offer new insight into the anti-tumor immune system with therapeutic implications.