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.

Implications of the central metal abundance peak in cooling core clusters of galaxies

Abstract: Recent XMM-Newton observations of clusters of galaxies have provided detailed information on the distribution of heavy elements in the central regions of clusters with cooling cores providing strong evidence that most of these metals come from recent SN type Ia. In this paper we compile information on the cumulative mass profiles of iron, the most important metallicity tracer. We find that long enrichment times (≥5 Gyr) are necessary to produce the central abundance peaks. Classical cooling flows, a strongly convective intracluster medium, and a complete metal mixing by cluster mergers would destroy the observed abundance peaks too rapidly. Thus the observations set strong constraints on cluster evolution models requiring that the cooling cores in clusters are preserved over very long times. We further conclude from the observations that the innermost part of the intracluster medium is most probably dominated by gas originating predominantly from stellar mass loss of the cD galaxy.

Lead-free piezoelectric ceramics based on perovskite structures

Abstract: The piezoelectric properties of a solid solution based on three components of bismuth sodium titanate (Bi1/2Na1/2)TiO3 (BNT), bismuth potassium titanate, (Bi1/2K1/2)TiO3 (BKT), and barium titanate, BaTiO3 (BT), that is x(Bi1/2Na1/2)TiO3−y(Bi1/2K1/2)TiO3−zBaTiO3, [ $$ x + y + z = 1 $$ , abbreviated as BNBKy:z(x)] and potassium niobate, KNbO3 (KN) based ceramics, that is KN+MnCO3 x wt.%, [abbreviated as KN−Mn x], were studied as a lead-free piezoelectric material. In the case of BNBK2:1 system, high piezoelectric properties were obtained near the MPB composition, and the highest electromechanical coupling factor, k 33 and piezoelectric constant, d 33, were 0.58 for BNBK2:1(0.89) and 181 pC/N for BNBK2:1(0.88). Nevertheless, the depolarization temperature, T d , shifts to lower temperature around the MPB compositions, and the T d ’s of BNBK2:1(0.88–0.90) are only about 100 °C. On the tetragonal side, the T d shifts to higher temperature with increasing the lattice anisotropy, c/a. As T d higher than 200 °C was obtained in the range of x < 0.78, with a k 33 and d 33 for BNBK2:1(0.78) being 0.45 and 128 pC/N, respectively. In the case of Mn doped KN ceramics, dense and non deliquescence KN ceramic were successfully obtained via ordinary firing technique in air by optimizing the fabrication process. Mn doping for KN ceramics was effective to obtain full poling state easily under poling conditions of high temperature and high electric field. As a result, we obtained the excellent piezoelectric properties of k 33 = 0.507 for KN−Mn0.2.

Observational Constraints on Loop Quantum Cosmology

Abstract: In the inflationary scenario of loop quantum cosmology in the presence of inverse-volume corrections, we give analytic formulas for the power spectra of scalar and tensor perturbations convenient to compare with observations. Since inverse-volume corrections can provide strong contributions to the running spectral indices, inclusion of terms higher than the second-order runnings in the power spectra is crucially important. Using the recent data of cosmic microwave background and other cosmological experiments, we place bounds on the quantum corrections.

Dectin-1 Contributes to Myocardial Ischemia/Reperfusion Injury by Regulating Macrophage Polarization and Neutrophil Infiltration

Abstract: Background: Macrophage-associated immune response plays an important role in myocardial ischemia/reperfusion (IR) injury. Dectin-1, expressed mainly on activated myeloid cells, is crucial for the r...

Nanospheres for DNA separation chips.

Abstract: We report here a technology to carry out separations of a wide range of DNA fragments with high speed and high resolution. The approach uses a nanoparticle medium, core-shell type nanospheres, in conjunction with a pressurization technique during microchip electrophoresis. DNA fragments up to 15 kilobase pairs (kbp) were successfully analyzed within 100 s without observing any saturation in migration rates. DNA fragments migrate in the medium while maintaining their characteristic molecular structure. To guarantee effective DNA loading and electrofocusing in the nanosphere solution, we developed a double pressurization technique. Optimal pressure conditions and concentrations of packed nanospheres are critical to achieve improved DNA separations.