Saitama University

About: Saitama University is a education organization based out in Saitama, Japan. It is known for research contribution in the topics: Catalysis & Gene. The organization has 7620 authors who have published 13432 publications receiving 239945 citations. The organization is also known as: Saitama Daigaku.

A short γ-ray burst apparently associated with an elliptical galaxy at redshift z = 0.225

Abstract: Gamma-ray bursts (GRBs) are either ‘long and soft’, or ‘short and hard’. The long-duration type leave a strong afterglow and have been extensively studied. So we have a good idea of what causes them: explosions of massive stars in distant star-forming galaxies. Short GRBs, with no strong afterglow, were harder to pin down. The Swift satellite, launched last November, is designed to study bursts as soon as they happen. Having shown its worth with long GRBs (reported in the 18 August issue of Nature), Swift has now bagged a short burst, GRB 050509B, precisely measured its location and detected the X-ray afterglow. Four papers this week report on this and another recent short burst. Now, over 20 years after they were first recognized, the likely origin of the short GRBs is revealed as a merger between neutron stars of a binary system and the instantaneous production of a black hole. Gamma-ray bursts (GRBs) come in two classes1: long (> 2 s), soft-spectrum bursts and short, hard events. Most progress has been made on understanding the long GRBs, which are typically observed at high redshift (z ≈ 1) and found in subluminous star-forming host galaxies. They are likely to be produced in core-collapse explosions of massive stars2. In contrast, no short GRB had been accurately (< 10″) and rapidly (minutes) located. Here we report the detection of the X-ray afterglow from—and the localization of—the short burst GRB 050509B. Its position on the sky is near a luminous, non-star-forming elliptical galaxy at a redshift of 0.225, which is the location one would expect3,4 if the origin of this GRB is through the merger of neutron-star or black-hole binaries. The X-ray afterglow was weak and faded below the detection limit within a few hours; no optical afterglow was detected to stringent limits, explaining the past difficulty in localizing short GRBs.

Hard X-Ray Detector (HXD) on Board Suzaku

Abstract: The Hard X-ray Detector (HXD) on board Suzaku covers a wide energy range from 10 keV to 600 keV by combination of silicon PIN diodes and GSO scintillators. The HXD is designed to achieve an extremely low in-orbit background based on a combination of new techniques, including the concept of well-type active shield counter. With an effective area of 142 cm at 20 keV and 273 cm at 150 keV, the background level at the sea level reached ∼ 1×10 cts s cm keV at 30 keV for the PIN diodes, and ∼ 2×10 cts s cm keV at 100 keV, and ∼ 7×10 cts s cm keV at 200 keV for the phoswich counter. Tight active shielding of the HXD results in a large array of guard counters surrounding the main detector parts. These anti-coincidence counters, made of ∼4 cm thick BGO crystals, have a large effective area for sub-MeV to MeV γ-rays. They work as an excellent γ-ray burst monitor with limited angular resolution ( ∼ 5). The on-board signal-processing system and the data transmitted to the ground are also described.

Allogeneic transplantation of iPS cell-derived cardiomyocytes regenerates primate hearts

Abstract: Induced pluripotent stem cells (iPSCs) constitute a potential source of autologous patient-specific cardiomyocytes for cardiac repair, providing a major benefit over other sources of cells in terms of immune rejection. However, autologous transplantation has substantial challenges related to manufacturing and regulation. Although major histocompatibility complex (MHC)-matched allogeneic transplantation is a promising alternative strategy, few immunological studies have been carried out with iPSCs. Here we describe an allogeneic transplantation model established using the cynomolgus monkey (Macaca fascicularis), the MHC structure of which is identical to that of humans. Fibroblast-derived iPSCs were generated from a MHC haplotype (HT4) homozygous animal and subsequently differentiated into cardiomyocytes (iPSC-CMs). Five HT4 heterozygous monkeys were subjected to myocardial infarction followed by direct intra-myocardial injection of iPSC-CMs. The grafted cardiomyocytes survived for 12 weeks with no evidence of immune rejection in monkeys treated with clinically relevant doses of methylprednisolone and tacrolimus, and showed electrical coupling with host cardiomyocytes as assessed by use of the fluorescent calcium indicator G-CaMP7.09. Additionally, transplantation of the iPSC-CMs improved cardiac contractile function at 4 and 12 weeks after transplantation; however, the incidence of ventricular tachycardia was transiently, but significantly, increased when compared to vehicle-treated controls. Collectively, our data demonstrate that allogeneic iPSC-CM transplantation is sufficient to regenerate the infarcted non-human primate heart; however, further research to control post-transplant arrhythmias is necessary.

Characteristic spectra of Munsell colors

Abstract: The 1257 reflectance spectra of the chips in the Munsell Book of Color—Matte Finish Collection (Munsell Color, Baltimore, Md., 1976) were measured with a rapid acousto-optic spectrophotometer. Measured spectra were sampled from 400 to 700 nm at 5-nm intervals. The correlation matrix of this sample set was formed, and the characteristic vectors of this matrix were computed. It is shown, contradictory to earlier recommendations [ Psychon. Sci.1, 369 ( 1964)], that as many as eight characteristic spectra are needed to achieve good representation for all spectra.

Highly efficient gene replacements in Neurospora strains deficient for nonhomologous end-joining.

Abstract: Gene disruption and overexpression play central roles in the analysis of gene function Homologous recombination is, in principle, the most efficient method of disrupting, modifying, or replacing a target gene Although homologous integration of exogenous DNA into the genome occurs readily in Saccharomyces cerevisiae, it is rare in many other organisms We identified and disrupted Neurospora crassa genes homologous to human KU70 and KU80, which encode proteins that function in nonhomologous end-joining of double-stranded DNA breaks The resulting mutants, named mus-51 and mus-52, showed higher sensitivity to methyl methanesulfonate, ethyl methanesulfonate, and bleomycin than wild type, but not to UV, 4-nitroquinoline 1-oxide, camptothecin, or hydroxyurea Vegetative growth, conidiation, and ascospore production in homozygous crosses were normal The frequency of integration of exogenous DNA into homologous sequences of the genome in the KU disruption strains of N crassa was compared with that in wild type, mei-3, and mus-11 In mei-3 and mus-11, which are defective in homologous recombination, none or few homologous integration events were observed under any conditions When mtr target DNA with ≈2-kb 5′ and 3′ flanking regions was used for transformation of the KU disruption strains, 100% of transformants exhibited integration at the homologous site, compared to 10 to 30% for a wild-type recipient Similar results were obtained when the ad-3A gene was targeted for disruption These results indicate that KU disruption strains are efficient recipients for gene targeting