Tokyo University of Science

About: Tokyo University of Science is a education organization based out in Tokyo, Japan. It is known for research contribution in the topics: Catalysis & Thin film. The organization has 15800 authors who have published 24147 publications receiving 438081 citations. The organization is also known as: Tōkyō Rika Daigaku & Science University of Tokyo.

Nanostructured TiO2 and Its Application in Lithium‐Ion Storage

Abstract: Titania nanorods and nanowires are synthesized via a hydrothermal reaction of amorphous TiO2 in alkaline NaOH, followed by ion exchange in HCl aqueous solution, and dehydration at 400 °C. Although the hydrothermal treatment produces three different particle morphologies depending on the reaction time (nanosheets, nanorods, and nanowires), the products exhibit the same crystal structure. Ion exchange of Na2Ti3O7 in HCl aqueous solution brings about a phase change to H2Ti3O7, but there is no change in the particle morphology. Dehydration of the nanostructured H2Ti3O7 leads to two types of crystal structure—anatase TiO2 for the nanorods, and TiO2–B for the nanowires—although no significant difference is found in the morphology of the products even after dehydration. The nanorods are 40–50 nm in length and 10 nm in diameter, whereas the nanowires are several micrometers in length and tens to hundreds of nanometers in thickness. In-situ X-ray diffraction revealed the formation of anatase TiO2 from the TiO2–B above 450 °C. This finding implies that the phase transformation occurs rather slowly for the TiO2–B nanowires due to the larger particle size and higher crystallinity of H2Ti3O7. Tests with Li-metal half cells indicated that the anatase TiO2 nanorods are more favorable for the storage and release of Li ions because of their greater surface area than the TiO2–B nanowires.

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.

Identifying Strategies That Facilitate EFL Learners' Oral Communication: A Classroom Study Using Multiple Data Collection Procedures

Abstract: This article considers whether the use of specific communication strategies can improve learners' English proficiency in communicative tasks. Japanese college students ( n = 62) participated in a 12-week course of English lessons using a communicative approach with strategy training. To investigate the influence of specific strategy use, their performance on a posttraining conversation test was analyzed through multiple data collection procedures. Transcripts of the test were made and then analyzed in terms of production rate, the number of errors, and actual strategy use. An Oral Communication Strategy Inventory was introduced to elicit participants' communication strategy use for a self-report questionnaire procedure. These results were compared with participants' retrospective protocol data regarding their oral test performance. The findings confirmed that strategies for maintaining discourse and negotiation of meaning could enhance learners' communicative ability. Yet the students used a relatively small number of examples of modified output, which indicated that they might not have enough opportunities to improve the form of their utterances. [ABSTRACT FROM AUTHOR]

Ruthenium-catalyzed propargylic substitution reactions of propargylic alcohols with oxygen-, nitrogen-, and phosphorus-centered nucleophiles.

Abstract: The scope and limitations of the ruthenium-catalyzed propargylic substitution reaction of propargylic alcohols with heteroatom-centered nucleophiles are presented. Oxygen-, nitrogen-, and phosphorus-centered nucleophiles such as alcohols, amines, amides, and phosphine oxide are available for this catalytic reaction. Only the thiolate-bridged diruthenium complexes can work as catalysts for this reaction. Results of some stoichiometric and catalytic reactions indicate that the catalytic propargylic substitution reaction proceeds via an allenylidene complex formed in situ, whereby the attack of nucleophiles to the allenylidene C(gamma) atom is a key step. Investigation of the relative rate constants for the reaction of propargylic alcohols with several para-substituted anilines reveals that the attack of anilines on the allenylidene C(gamma) atom is not involved in the rate-determining step and rather the acidity of conjugated anilines of an alkynyl complex, which is formed after the attack of aniline on the C(gamma) atom, is considered to be the most important factor to determine the rate of this catalytic reaction. The key point to promote this catalytic reaction by using the thiolate-bridged diruthenium complexes is considered to be the ease of the ligand exchange step between a vinylidene ligand on the diruthenium complexes and another propargylic alcohol in the catalytic cycle. The reason why only the thiolate-bridged diruthenium complexes promote the ligand exchange step more easily with respect to other monoruthenium complexes in this catalytic reaction should be that one Ru moiety, which is not involved in the allenylidene formation, works as an electron pool or a mobile ligand to another Ru site. The catalytic procedure presented here provides a versatile, direct, and one-step method for propargylic substitution of propargylic alcohols in contrast to the so far well-known stoichiometric and stepwise Nicholas reaction.