167 research outputs found

    Searching for a Companion Star of Tycho's Type Ia Supernova with Optical Spectroscopic Observations

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    We report our first results of photometric and spectroscopic observations for Tycho's supernova remnant (SNR Tycho) to search for the companion star of a type Ia supernova (SN Ia). From photometric observations using Suprime-Cam on the Subaru Telescope, we have picked up stars brighter than 22 mag (in VV-band) for spectroscopy, which are located within a circular region with the radius of 30" around the center of SNR Tycho. If the ejecta of young supernova remnants, such as SNR Tycho, have a sufficient amount of Fe I, we should be able to detect absorption lines at 3720 \AA and 3860 \AA associated with transitions from the ground state of Fe I in the spectrum of the companion star. To identify the companion star of a SN Ia using these characteristic absorption lines of Fe I, we made optical low-resolution spectroscopy of their targets using FOCAS on the Subaru Telescope. In our spectroscopic observations, we obtained spectra of 17 stars in the SNR Tycho region and compare them with template stellar spectra. We detect significant absorption lines from two stars at 3720 \AA. Since widths of their absorption lines are broad, it is likely that the detected absorptions are due to Fe I in the expanding ejecta of SNR Tycho. However, none of stars exhibits a clear red wing in the observed profiles of the absorption, though a star in the background of the SNR should show it. Hence, we suggest another interpretation that the detected absorption lines might be caused by the peculiarity of stars. A star named Tycho(E) has the absorption line at 3720 \AA and its projected position is close to the center of SNR Tycho. Based on our observations, Tycho(E) is a new candidate as the companion star of Tycho's supernova.Comment: 17 pages, 28 figures, accepted for publication in PAS

    Chiroptical Polymer Functionalized by Chiral Nanofibrillar Network

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    Chirality is one of the basic factors that influence a wide range of activities from chemical synthesis to tissue construction in life phenomena. Recently, researchers have attempted to use chirality as an optical signal. In animals, it is used to transmit information to insects and crustaceans, and it has also been confirmed that it promotes growth in plants. This chapter presents a new organic system that produces a chiral optical signal, that is, circularly polarized luminescence (CPL), which has been attracting attention in recent years. In particular, the chapter is focused on the generating CPL through chirality induction with the chiral self-assembling phenomenon and explaining its application as an optical film

    The Type Ia supernovae rate with Subaru/XMM-Newton Deep Survey

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    We present measurements of the rates of high-redshift Type Ia supernovae derived from the Subaru/XMM-Newton Deep Survey (SXDS). We carried out repeat deep imaging observations with Suprime-Cam on the Subaru Telescope, and detected 1040 variable objects over 0.918 deg2^2 in the Subaru/XMM-Newton Deep Field. From the imaging observations, light curves in the observed ii'-band are constructed for all objects, and we fit the observed light curves with template light curves. Out of the 1040 variable objects detected by the SXDS, 39 objects over the redshift range 0.2<z<1.40.2 < z < 1.4 are classified as Type Ia supernovae using the light curves. These are among the most distant SN Ia rate measurements to date. We find that the Type Ia supernova rate increase up to z0.8z \sim 0.8 and may then flatten at higher redshift. The rates can be fitted by a simple power law, rV(z)=r0(1+z)αr_V(z)=r_0(1+z)^\alpha with r0=0.200.16+0.52r_0=0.20^{+0.52}_{-0.16}(stat.)0.07+0.26^{+0.26}_{-0.07}(syst.)×104yr1Mpc3\times 10^{-4} {\rm yr}^{-1}{\rm Mpc}^{-3}, and α=2.041.96+1.84\alpha=2.04^{+1.84}_{-1.96}(stat.)0.86+2.11^{+2.11}_{-0.86}(syst.).Comment: 21 pages, 16 figures, accepted to PAS

    Nondestructive Evaluation of Wet Aged Beef by Novel Electrical Indexes: A Preliminary Study

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    The aim of this study was to investigate the suitability of electrical impedance spectroscopy (EIS) as a nondestructive quality monitoring tool of aged beef, focusing on the development of accurate electrical indexes. The relationship between the electrical indexes derived from the impedance ratio (IR) or admittance was established. Quality parameters such as the drip loss, cooking loss, water-holding capacity, and shear force of beef loin wet-aged for 0 to 21 days were evaluated to develop the new electrical indexes. In addition, the predictive capability of EIS was trialed using different indexes and frequencies. This study revealed that the most appropriate choice is to use electrical parameters at a lower frequency to determine or predict the physical properties of aged beef. The IR was derived from the ratio between the electrical impedance measured parallel to and perpendicular to the muscle fibers in the low-frequency domain. Furthermore, the degradation of muscle fibers was observed by optical microscopy. The investigated electrical indexes had higher correlations with shear force (0.52 ≤ R2 ≤ 0.58) compared to correlations with aging days (0.34 ≤ R2 ≤ 0.39). The findings of the study could be used for meat quality inspection in slaughterhouses as well as during aging

    Antioxidant α-tocopherol ameliorates glycemic control of GK rats, a model of type 2 diabetes

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    AbstractWe have shown recently that oxidative stress by chronic hyperglycemia damages the pancreatic β-cells of GK rats, a model of non-obese type 2 diabetes, which may worsen diabetic condition and suggested the administration of antioxidants as a supportive therapy. To determine if natural antioxidant α-tocopherol (vitamin E) has beneficial effects on the glycemic control of type 2 diabetes, GK rats were fed a diet containing 0, 20 or 500 mg/kg diet α-tocopherol. Intraperitoneal glucose tolerance test revealed a significant increment of insulin secretion at 30 min and a significant decrement of blood glucose levels at 30 and 120 min after glucose loading in the GK rats fed with high α-tocopherol diet. The levels of glycated hemoglobin A1c, an indicator of glycemic control, were also reduced. Vitamin E supplementation clearly ameliorated diabetic control of GK rats, suggesting the importance of not only dietary supplementation of natural antioxidants but also other antioxidative intervention as a supportive therapy of type 2 diabetic patients

    [1.1]meta-Stilbenophanes as calixarene analogs: preparation, crystal structure, and cis-trans photoisomerization

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    Abstract-Three isomers of [1.1]meta-stilbenophane were synthesized by the McMurry reaction of diarylmethane dialdehyde and their crystal structures and photochemical properties were investigated. X-ray crystallographic analyses of these isomers revealed that they were assigned to a trans-trans (t-t) form with a 1,3-alternate conformation, a cis-trans (c-t) form with a distorted-cone conformation, and a cis-cis (c-c) form with a 1,2-alternate conformation. A 1 H NMR study indicated that a t-t isomer could be completely transformed into a 35:65 mixture of c-t and c-c isomers by photoirradiation at 254 nm

    Recombinant human FGF-2 for the treatment of early-stage osteonecrosis of the femoral head: TRION, a single-arm, multicenter, Phase II trial

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    Aim: This study aimed to evaluate the 2-year outcomes from a clinical trial of recombinant human FGF-2 (rhFGF-2) for osteonecrosis of the femoral head (ONFH). Patients & methods: Sixty-four patients with nontraumatic, precollapse and large ONFHs were percutaneously administered with 800 μg rhFGF-2 contained in gelatin hydrogel. Setting the end point of radiological collapse, we analyzed the joint preservation period of the historical control. Changes in two validated clinical scores, bone regeneration and safety were evaluated. Results: Radiological joint preservation time was significantly higher in the rhFGF-2 group than in the control group. The ONFHs tended to improve to smaller ONFHs. The postoperative clinical scores significantly improved. Thirteen serious adverse events showed recovery. Conclusion: rhFGF-2 treatment increases joint preservation time with clinical efficacy, radiological bone regeneration and safety
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