99 research outputs found
Spectral evolution of GRB 060904A observed with Swift and Suzaku -- Possibility of Inefficient Electron Acceleration
We observed an X-ray afterglow of GRB 060904A with the Swift and Suzaku
satellites. We found rapid spectral softening during both the prompt tail phase
and the decline phase of an X-ray flare in the BAT and XRT data. The observed
spectra were fit by power-law photon indices which rapidly changed from to within a few hundred
seconds in the prompt tail. This is one of the steepest X-ray spectra ever
observed, making it quite difficult to explain by simple electron acceleration
and synchrotron radiation. Then, we applied an alternative spectral fitting
using a broken power-law with exponential cutoff (BPEC) model. It is valid to
consider the situation that the cutoff energy is equivalent to the synchrotron
frequency of the maximum energy electrons in their energy distribution. Since
the spectral cutoff appears in the soft X-ray band, we conclude the electron
acceleration has been inefficient in the internal shocks of GRB 060904A. These
cutoff spectra suddenly disappeared at the transition time from the prompt tail
phase to the shallow decay one. After that, typical afterglow spectra with the
photon indices of 2.0 are continuously and preciously monitored by both XRT and
Suzaku/XIS up to 1 day since the burst trigger time. We could successfully
trace the temporal history of two characteristic break energies (peak energy
and cutoff energy) and they show the time dependence of while the following afterglow spectra are quite stable. This fact
indicates that the emitting material of prompt tail is due to completely
different dynamics from the shallow decay component. Therefore we conclude the
emission sites of two distinct phenomena obviously differ from each other.Comment: 19 pages, 9 figures, accepted for publication in PASJ (Suzaku 2nd
Special Issue
Emerin plays a crucial role in nuclear invagination and in the nuclear calcium transient.
Alteration of the nuclear Ca2+ transient is an early event in cardiac remodeling. Regulation of the nuclear Ca2+ transient is partly independent of the cytosolic Ca2+ transient in cardiomyocytes. One nuclear membrane protein, emerin, is encoded by EMD, and an EMD mutation causes Emery-Dreifuss muscular dystrophy (EDMD). It remains unclear whether emerin is involved in nuclear Ca2+ homeostasis. The aim of this study is to elucidate the role of emerin in rat cardiomyocytes by means of hypertrophic stimuli and in EDMD induced pluripotent stem (iPS) cell-derived cardiomyocytes in terms of nuclear structure and the Ca2+ transient. The cardiac hypertrophic stimuli increased the nuclear area, decreased nuclear invagination, and increased the half-decay time of the nuclear Ca2+ transient in cardiomyocytes. Emd knockdown cardiomyocytes showed similar properties after hypertrophic stimuli. The EDMD-iPS cell-derived cardiomyocytes showed increased nuclear area, decreased nuclear invagination, and increased half-decay time of the nuclear Ca2+ transient. An autopsied heart from a patient with EDMD also showed increased nuclear area and decreased nuclear invagination. These data suggest that Emerin plays a crucial role in nuclear structure and in the nuclear Ca2+ transient. Thus, emerin and the nuclear Ca2+ transient are possible therapeutic targets in heart failure and EDMD. © The Author(s) 2017
Purification and characterization of UDP-glucose: hydroxycoumarin 7-O-glucosyltransferase, with broad substrate specificity from tobacco cultured cells
The enzyme UDP-glucose: hydroxycoumarin 7-O-glucosyltransferase (CGTase), which catalyzes the formation of scopolin from scopoletin, was purified approximately 1200-fold from a culture of 2,4-D-treated tobacco cells (Nicotiana tabacum L. cv. Bright Yellow T-13) with a yield of 7%. Purification to apparent homogeneity, as judged by SDS-PAGE, was achieved by sequential anion-exchange chromatography, hydroxyapatite chromatography, gel filtration, a second round of anion-exchange chromatography, and affinity chromatography on UDP-glucuronic acid agarose. The purified enzyme had a pH optimum of 7.5, an isoelectric point (pI) of 5.0, and a molecular mass of 49 kDa. The enzyme did not require metal cofactors for activity. Its activity was inhibited by Zn2+, Co2+ and Cu2+ ions, as well as by SH-blocking reagents. The K-m values for UDP-glucose, scopoletin and esculetin were 43, 150 and 25 mu M. respectively. A study of the initial rate of the reaction suggested that the reaction proceeded via a sequential mechanism. The purified enzyme preferred hydroxycoumarins as substrates but also exhibited significant activity with flavonoids. A database search using the amino terminus amino acid sequence of CGTase revealed strong homology to the amino acid sequences of other glucosyltransferases in plants.ArticlePlant Science. 157(1):105-112 (2000)journal articl
CNVs in Three Psychiatric Disorders
BACKGROUND: We aimed to determine the similarities and differences in the roles of genic and regulatory copy number variations (CNVs) in bipolar disorder (BD), schizophrenia (SCZ), and autism spectrum disorder (ASD).
METHODS: Based on high-resolution CNV data from 8708 Japanese samples, we performed to our knowledge the largest cross-disorder analysis of genic and regulatory CNVs in BD, SCZ, and ASD.
RESULTS: In genic CNVs, we found an increased burden of smaller (500 kb) exonic CNVs in SCZ/ASD. Pathogenic CNVs linked to neurodevelopmental disorders were significantly associated with the risk for each disorder, but BD and SCZ/ASD differed in terms of the effect size (smaller in BD) and subtype distribution of CNVs linked to neurodevelopmental disorders. We identified 3 synaptic genes (DLG2, PCDH15, and ASTN2) as risk factors for BD. Whereas gene set analysis showed that BD-associated pathways were restricted to chromatin biology, SCZ and ASD involved more extensive and similar pathways. Nevertheless, a correlation analysis of gene set results indicated weak but significant pathway similarities between BD and SCZ or ASD (r = 0.25–0.31). In SCZ and ASD, but not BD, CNVs were significantly enriched in enhancers and promoters in brain tissue.
CONCLUSIONS: BD and SCZ/ASD differ in terms of CNV burden, characteristics of CNVs linked to neurodevelopmental disorders, and regulatory CNVs. On the other hand, they have shared molecular mechanisms, including chromatin biology. The BD risk genes identified here could provide insight into the pathogenesis of BD
Safety and tolerability of the olaparib tablet formulation in Japanese patients with advanced solid tumours
A phase I study of farletuzumab, a humanized anti-folate receptor α monoclonal antibody, in patients with solid tumors
A future plan in observing ultra-heavy nuclei (Z=30-110) of cosmic rays with large-scale collector at the lunar base
Lunar-based measurement of galactic cosmic ray (GCR) nuclei with a high precision is a challenging approach in cosmic ray research for the coming 20 years. This approach focuses to measure the elemental composition of Pt- and Pb-groups, actinide and possibly trans-uranic nuclei of Pu and Cm. The observation covers a wide range of scientific themes including the study on the origin of GCR nuclei, the characteristic time, heating and acceleration mechanism of GCR particles. A large-scaled particle telescope is required in order to measure those nuclides with high precision. Solid state nuclear track detectors (SSTDs) with a geometric factor of about 1000 m2sr allow us to measure them easily. Fluorescent nuclear track detector such as Al2O3 doped with C and Mg is the best candidate at present among SSTDs for a lunar-based experiment which is currently the focus of an international program of scientific investigation. A permanent sunshine region near crater at lunar polar region is thought to be an excellent site. A two-year-exposure by the large-scaled telescope would result in the detection of about 30,000 actinides in GCRs
YITP Workshop on Theoretical Problems at the Interface of Particle and Nuclear Physics : from Hadronic Matter to Quark Matter, Evolving View of Hadronic Matter
Long-Term Variation of the Solar Activity and its Possible Connection with the Earth\u27s Climate Condition and Cosmic Ray Modulation
The sun is quite variable in time. When the solar activity is numerated by counting sunspots in number, there exists a so-called eleven year periodicity on the relative sunspot numbers, although this periodicity varies from about 7 to 13 years. The total relative sunspot numbers for respective solar cycles have been increasing almost monotonically for more than 100 years since 1882. This long-term variation as seen on these numbers may have been causally associated with the decrease of the rotation speed at the equator of the sun which has been endured throughout those years since 1882. This long-term increase of the solar activity necessarily introduces its associated increase of the intensity of magnetic field originated from the sun in the inner heliosphere. The intensification of this field seems to strongly influence the behavior of galactic cosmic rays deep in the inner heliosphere and thus indirectly influences the sun - climate condition since the terrestrial climate may be highly dependent in the long-term decrease of the cosmic ray influx into the earth\u27s atmosphere
- …