Tokyo Institute of Technology

About: Tokyo Institute of Technology is a education organization based out in Tokyo, Tôkyô, Japan. It is known for research contribution in the topics: Catalysis & Thin film. The organization has 46775 authors who have published 101656 publications receiving 2357893 citations. The organization is also known as: Tokyo Tech & Tokodai.

Comparative genomics reveal the mechanism of the parallel evolution of O157 and non-O157 enterohemorrhagic Escherichia coli

Abstract: Among the various pathogenic Escherichia coli strains, enterohemorrhagic E. coli (EHEC) is the most devastating. Although serotype O157:H7 strains are the most prevalent, strains of different serotypes also possess similar pathogenic potential. Here, we present the results of a genomic comparison between EHECs of serotype O157, O26, O111, and O103, as well as 21 other, fully sequenced E. coli/Shigella strains. All EHECs have much larger genomes (5.5–5.9 Mb) than the other strains and contain surprisingly large numbers of prophages and integrative elements (IEs). The gene contents of the 4 EHECs do not follow the phylogenetic relationships of the strains, and they share virulence genes for Shiga toxins and many other factors. We found many lambdoid phages, IEs, and virulence plasmids that carry the same or similar virulence genes but have distinct evolutionary histories, indicating that independent acquisition of these mobile genetic elements has driven the evolution of each EHEC. Particularly interesting is the evolution of the type III secretion system (T3SS). We found that the T3SS of EHECs is composed of genes that were introduced by 3 different types of genetic elements: an IE referred to as the locus of enterocyte effacement, which encodes a central part of the T3SS; SpLE3-like IEs; and lambdoid phages carrying numerous T3SS effector genes and other T3SS-related genes. Our data demonstrate how E. coli strains of different phylogenies can independently evolve into EHECs, providing unique insights into the mechanisms underlying the parallel evolution of complex virulence systems in bacteria.

Effect of A- and B-cation substitutions on the phase stability of PbTiO 3 ceramics

Abstract: Raman scattering studies of Nd-modified lead titanate ${\mathrm{Pb}}_{1\ensuremath{-}3y/2}{\mathrm{Nd}}_{y}{\mathrm{TiO}}_{3}$ (PNT), $y=0.02,$ 0.10, and $\mathrm{Pb}({\mathrm{Zr}}_{x}{\mathrm{Ti}}_{1\ensuremath{-}x}){\mathrm{O}}_{3}$ (PZT), $x=0.10,0.20,$ bulk ceramics were made at ambient temperatures between 4.2 and 297 K. Our measurements reveal splitting of the $E\ensuremath{\bigoplus}{B}_{1}$ symmetry peak at low temperatures in both the PNT and PZT samples. Some splitting of three $E(\mathrm{TO})\mathrm{}$ peaks in the PZT samples [except for the $E(2\mathrm{TO})$ peak in the sample with $x=0.10]$ and of the $E(3\mathrm{TO})$ peak in the PNT samples was also found. We discuss the phase stability of lead titanate based perovskites from the point of view of our experimental results and recent theoretical calculations. Raman results reveal that all ${A}_{1}(\mathrm{TO})$ symmetry modes in all samples are anharmonic down to the lowest measurement temperature.

Classification, terminology, and application of the modular multilevel cascade converter (MMCC)

Abstract: This paper presents the modular multilevel cascade converter (MMCC) family based on cascade connection of multiple reversible-chopper cells or multiple single-phase full-bridge cells. This converter family are classified from circuit configuration as follows; single-star bridge-cells (SSBC), singledelta bridge-cells (SDBC), double-star chopper-cells (DSCC), and double-star bridge-cells (DSBC). The term MMCC corresponds to a family name in a person while, for example, the term SSBC corresponds to a given name. Therefore, the term “MMCC-SSBC” can identify the circuit configuration without any confusion. Among the four circuit configurations, SSBC and DSCC are the most practical than the others in terms of cost and performance, although a distinct difference exists in application between SSBC and DSCC. This paper describes applications of SSBC and DSCC to a battery energy storage system and a motor drive, respectively.

Detection of 16 Gamma-Ray Pulsars Through Blind Frequency Searches Using the Fermi LAT

Abstract: Pulsars are rapidly rotating, highly magnetized neutron stars emitting radiation across the electromagnetic spectrum. Although there are more than 1800 known radio pulsars, until recently only seven were observed to pulse in gamma rays, and these were all discovered at other wavelengths. The Fermi Large Area Telescope (LAT) makes it possible to pinpoint neutron stars through their gamma-ray pulsations. We report the detection of 16 gamma-ray pulsars in blind frequency searches using the LAT. Most of these pulsars are coincident with previously unidentified gamma-ray sources, and many are associated with supernova remnants. Direct detection of gamma-ray pulsars enables studies of emission mechanisms, population statistics, and the energetics of pulsar wind nebulae and supernova remnants.

Index for three dimensional superconformal field theories with general R-charge assignments

Abstract: We derive a general formula of an index for three dimensional \( \mathcal{N} = 2 \) super-conformal field theories with general R-charge assignments to chiral multiplets by using the localization method in S2 × S1 background. As examples we compute the index for theories in a few mirror pairs, and confirm the agreement of the indices in each mirror pair.