University of Tokyo

About: University of Tokyo is a education organization based out in Tokyo, Japan. It is known for research contribution in the topics: Population & Gene. The organization has 134564 authors who have published 337567 publications receiving 10178620 citations. The organization is also known as: Todai & Universitas Tociensis.

GW190814: Gravitational Waves from the Coalescence of a 23 Solar Mass Black Hole with a 2.6 Solar Mass Compact Object

Abstract: We report the observation of a compact binary coalescence involving a 222–243 M ⊙ black hole and a compact object with a mass of 250–267 M ⊙ (all measurements quoted at the 90% credible level) The gravitational-wave signal, GW190814, was observed during LIGO's and Virgo's third observing run on 2019 August 14 at 21:10:39 UTC and has a signal-to-noise ratio of 25 in the three-detector network The source was localized to 185 deg2 at a distance of ${241}_{-45}^{+41}$ Mpc; no electromagnetic counterpart has been confirmed to date The source has the most unequal mass ratio yet measured with gravitational waves, ${0112}_{-0009}^{+0008}$, and its secondary component is either the lightest black hole or the heaviest neutron star ever discovered in a double compact-object system The dimensionless spin of the primary black hole is tightly constrained to ≤007 Tests of general relativity reveal no measurable deviations from the theory, and its prediction of higher-multipole emission is confirmed at high confidence We estimate a merger rate density of 1–23 Gpc−3 yr−1 for the new class of binary coalescence sources that GW190814 represents Astrophysical models predict that binaries with mass ratios similar to this event can form through several channels, but are unlikely to have formed in globular clusters However, the combination of mass ratio, component masses, and the inferred merger rate for this event challenges all current models of the formation and mass distribution of compact-object binaries

Functional SNPs in the lymphotoxin-alpha gene that are associated with susceptibility to myocardial infarction.

Abstract: By means of a large-scale, case-control association study using 92,788 gene-based single-nucleotide polymorphism (SNP) markers, we identified a candidate locus on chromosome 6p21 associated with susceptibility to myocardial infarction. Subsequent linkage-disequilibrium (LD) mapping and analyses of haplotype structure showed significant associations between myocardial infarction and a single 50 kb halpotype comprised of five SNPs in LTA (encoding lymphotoxin-alpha), NFKBIL1 (encoding nuclear factor of kappa light polypeptide gene enhancer in B cells, inhibitor-like 1) and BAT1 (encoding HLA-B associated transcript 1). Homozygosity with respect to each of the two SNPs in LTA was significantly associated with increased risk for myocardial infarction (odds ratio = 1.78, chi(2) = 21.6, P = 0.00000033; 1,133 affected individuals versus 1,006 controls). In vitro functional analyses indicated that one SNP in the coding region of LTA, which changed an amino-acid residue from threonine to asparagine (Thr26Asn), effected a twofold increase in induction of several cell-adhesion molecules, including VCAM1, in vascular smooth-muscle cells of human coronary artery. Moreover, the SNP, in intron 1 of LTA, enhanced the transcriptional level of LTA. These results indicate that variants in the LTA are risk factors for myocardial infraction and implicate LTA in the pathogenesis of the disorder.

The X-Ray Observatory Suzaku

Abstract: High-sensitivity wide-band X-ray spectroscopy is the key feature of the Suzaku X-ray observatory, launched on 2005 July 10. This paper summarizes the spacecraft, in-orbit performance, operations, and data processing that are related to observations. The scientific instruments, the high-throughput X-ray telescopes, X-ray CCD cameras, non-imaging hard X-ray detector are also described.

Self-Templated Synthesis of Nanoporous CdS Nanostructures for Highly Efficient Photocatalytic Hydrogen Production under Visible Light

Abstract: Nanoporous CdS nanostructures, including nanosheets and hollow nanorods, have been prepared by a two-step aqueous route, which consists of a first precipitation of nanoporous Cd(OH)2 intermediates and a subsequent S2−/OH− ion-exchange conversion of the obtained Cd(OH)2 used as template either to nanoporous CdS nanosheets with sizes up to 60 nm and an average thickness of about 9 nm or to CdS hollow nanorods with lengths up to 30 nm and outer diameters in the range 7–14 nm. The obtained CdS nanostructures containing nanopores with diameters of ∼3 nm exhibit a very large BET surface area of about 112.8 m2 g−1. A very high hydrogen yield of about 4.1 mmol h−1 under visible light irradiation (λ ≥ 420 nm), corresponding to the highest apparent quantum yield of about 60.34% measured at 420 nm so far reported, has been attained over the obtained nanoporous CdS nanostructures loaded with monodisperse 3–5 nm Pt nanocrystals, which is due to an efficient charge separation, a fast transport of the photogenerated car...

Spin liquid state in an organic Mott insulator with a triangular lattice.

Abstract: $^{1}\mathrm{H}$ NMR and static susceptibility measurements have been performed in an organic Mott insulator with a nearly isotropic triangular lattice, $\ensuremath{\kappa}\mathrm{\text{\ensuremath{-}}}(\mathrm{B}\mathrm{E}\mathrm{D}\mathrm{T}\mathrm{\text{\ensuremath{-}}}\mathrm{T}\mathrm{T}\mathrm{F}{)}_{2}{\mathrm{C}\mathrm{u}}_{2}(\mathrm{C}\mathrm{N}{)}_{3}$, which is a model system of frustrated quantum spins. The static susceptibility is described by the spin $S=1/2$ antiferromagnetic triangular-lattice Heisenberg model with the exchange constant $J\ensuremath{\sim}250\text{ }\text{ }\mathrm{K}$. Regardless of the large magnetic interactions, the $^{1}\mathrm{H}$ NMR spectra show no indication of long-range magnetic ordering down to 32 mK, which is 4 orders of magnitude smaller than $J$. These results suggest that a quantum spin liquid state is realized in the close proximity of the superconducting state appearing under pressure.