95 research outputs found

    Synthesis of Amphiphilic Three-Armed Star Random Copolymers via Living Radical Polymerization and their Unimolecular Folding Properties in Water

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    Amphiphilic three-armed star random copolymers were synthesized by ruthenium-catalyzed living radical copolymerization of hydrophilic poly(ethylene glycol) methyl ether methacrylate (PEGMA) and hydrophobic dodecyl methacrylate (DMA). Their amphiphilic star random copolymers with 10-50 mol% DMA efficiently self-folded in water with intramolecular hydrophobic interaction to form compact unimolecular micelles. Owing to PEG segments, star copolymers were thermoresponsive to induce lower critical solution temperature-type phase separation in water

    HLA-Haploidentical Peripheral Blood Stem Cell Transplantation with Post-Transplant Cyclophosphamide after Busulfan-Containing Reduced-Intensity Conditioning

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    AbstractAllogeneic hematopoietic stem cell transplantation (allo-SCT) using post-transplant cyclophosphamide (PTCy) is increasingly performed. We conducted a multicenter phase II study to evaluate the safety and efficacy of PTCy-based HLA-haploidentical peripheral blood stem cell transplantation (PTCy-haploPBSCT) after busulfan-containing reduced-intensity conditioning. Thirty-one patients were enrolled; 61% patients were not in remission and 42% patients had a history of prior allo-SCT. Neutrophil engraftment was achieved in 87% patients with a median of 19 days. The cumulative incidence of grades II to IV and III to IV acute graft-versus-host disease (GVHD) and chronic GVHD at 1 year were 23%, 3%, and 15%, respectively. No patients developed severe chronic GVHD. Day 100 nonrelapse mortality (NRM) rate was 19.4%. Overall survival, relapse, and disease-free survival rates were 45%, 45%, and 34%, respectively, at 1 year. Subgroup analysis showed that patients who had a history of prior allo-SCT had lower engraftment, higher NRM, and lower overall survival than those not receiving a prior allo-SCT. Our results suggest that PTCy-haploPBSCT after busulfan-containing reduced-intensity conditioning achieved low incidences of acute and chronic GVHD and NRM and stable donor engraftment and low NRM, particularly in patients without a history of prior allo-SCT

    Reviewing E(sub peak) Relations with Swift and Suzaku Data

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    In recent years several authors have derived correlations between gamma-ray burst (GRB) spectral peak energy (E(sub peak)) and either isotropic-equivalent radiated energy (E(sub iso)) or peak luminosity (L(sub iso)). Since these relationships are controversial, but could provide redshift estimators, it is important to determine whether bursts detected by Swift exhibit the same correlations. Swift has greatly added to the number of GRBs for which redshifts are known and hence E(sub iso) and L(sub iso) could be calculated. However, for most bursts it is not possible to adequately constrain E(sub peak) with Swift data alone since most GRBs have E(sub peak) above the energy range (15-50 keV) of the Swift Burst Alert Telescope (BAT). Therefore we have analyzed the spectra of 78 bursts (31 with redshift) which were detected by both Swift/BAT and the Suzaku Wide-band All-sky Monitor (WAM), which covers the energy range 50-5000 keV. For most bursts in this sample we can precisely determine E(sub peak) and for bursts with known redshift we can compare how the E(sub peak) relations for the Swift/Suzaku sample compare to earlier published results. Keywords: gamma rays: burst

    Spectral Properties of Prompt Emission of Four Short Gamma-Ray Bursts Observed by the Suzaku-WAM and the Konus-Wind

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    We have performed a joint analysis of prompt emission from four bright short gamma-ray bursts (GRBs) with the Suzaku-WAM and the Konus-Wind experiments. This joint analysis allows us to investigate the spectral properties of short-duration bursts over a wider energy band with a higher accuracy. We find that these bursts have a high Epeak_{\rm peak}, around 1 MeV and have a harder power-law component than that of long GRBs. However, we can not determine whether these spectra follow the cut-off power-law model or the Band model. We also investigated the spectral lag, hardness ratio, inferred isotropic radiation energy and existence of a soft emission hump, in order to classify them into short or long GRBs using several criteria, in addition to the burst duration. We find that all criteria, except for the existence of the soft hump, support the fact that our four GRB samples are correctly classified as belonging to the short class. In addition, our broad-band analysis revealed that there is no evidence of GRBs with a very large hardness ratio, as seen in the BATSE short GRB sample, and that the spectral lag of our four short GRBs is consistent with zero, even in the MeV energy band, unlike long GRBs. Although our short GRB samples are still limited, these results suggest that the spectral hardness of short GRBs might not differ significantly from that of long GRBs, and also that the spectral lag at high energies could be a strong criterion for burst classification.Comment: 23 pages, 6 figures, accepted for Publications of the Astronomical Society of Japa

    An Optically Dark GRB Observed by HETE-2: GRB 051022

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    GRB 051022 was detected at 13:07:58 on 22 October 2005 by HETE-2. The location of GRB 051022 was determined immediately by the flight localization system. This burst contains multiple pulses and has a rather long duration of about 190 seconds. The detections of candidate X-ray and radio afterglows were reported, whereas no optical afterglow was found. The optical spectroscopic observations of the host galaxy revealed the redshift z = 0.8. Using the data derived by HETE-2 observation of the prompt emission, we found the absorption N_H = 8.8 -2.9/+3.1 x 10^22 cm^-2 and the visual extinction A_V = 49 -16/+17 mag in the host galaxy. If this is the case, no detection of any optical transient would be quite reasonable. The absorption derived by the Swift XRT observations of the afterglow is fully consistent with those obtained from the early HETE-2 observation of the prompt emission. Our analysis implies an interpretation that the absorbing medium could be outside external shock at R ~ 10^16 cm, which may be a dusty molecular cloud.Comment: 6 pages, 2 figures, accepted for publication in PASJ lette

    Active Learning Models in Science Classes

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    研究の第1年次に当たる本年は,理科におけるアクティブラーニング型授業の構造化に向けて,内化と外化の往還を取り入れた授業デザインとその実践に取り組み,具体的実践の蓄積を行った。小学校,中学校,高等学校それぞれで実践を行ったところ,1)学習内容の定着が図られる,2)発展的な内容や未習内容を生徒が主体的に理解することが可能である,3)協働的な学びの場面を加えることで理解の深化が図られる,4)どのような課題に取り組ませるのかといった課題の設定がカギである,5)アクティブラーニングであるか否かを判断するための要素を明らかにする必要がある,などの一定の成果と課題が明らかになった。The purpose of this study is to create active learning models in science classes. As the first-year research, the authors designed the classes which would include a round trip between externalization and internalization, and put them into practice. The designed models were adopted in elementary, junior high and senior high school classes. What have become clear are as the following; 1) Students’ acquisition of the learning contents can be promoted, 2) Students can understand advanced contents proactively, 3) Students’ learning can be deepened by adding collaborative activities, 4) The success or failure to active learning may depend on the quality of the tasks which students work on, 5) It is necessary to clarify the factors to determine active learning

    The Role of Science Education in the Construction of a Knowledge-Based Society

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    知識基盤社会における理科の役割は,科学的に探究する活動を通して得られた結果(情報)を活用し,それらの情報から導き出した自らの考えを表現する能力を高めることである。これまでに明らかになったことは,授業者が実験結果に対して関連付けることができる事項を明確にし,分析・解釈する視点を与えることが重要であるということである。今年度は,小学校,中学校,高等学校の理科で,パフォーマンス課題を取り入れた探究活動を行い,多くの授業者が共有できる方向性を考えた。実践の結果,以下のことが明らかになった。1)小集団での話し合いの質を高めるためには,話し合いの目的と方法を明示することが重要であること。2)そのために授業者の関わり方を引き続き検討する必要があること。3)パフォーマンス課題の設計には授業者がよりメタ認知を働かせることが必要であること。今後は,このような実践経験を広く共有すべきであると考えている。Science education should help students to utilize results and information through activities, to investigate scientifically, and to develop their abilities to express ideas they have derived from those results. We have learned that it is important for instructors to clarify which results from experiments relate to each other and to give students some clear perspectives for analyzing and interpreting them. This academic year, we investigated performance tasks at elementary, junior high, and senior high school levels. Through our research we have learned that to improve the quality of discussion in small groups, it is important to make the purpose and method clear. We also showed that instructors should monitor how they engage with students in the course of discussion and that they need to function meta-cognitive abilities more to design performance tasks

    HETE-2 Observations of the X-Ray Flash XRF 040916

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    A long X-ray flash was detected and localized by the instruments aboard the High Energy Transient Explorer II (HETE-2) at 00:03:30 UT on 2004 September 16. The position was reported to the GRB Coordinates Network (GCN) approximately 2 hours after the burst. This burst consists of two peaks separated by 200 s, with durations of 110 s and 60 s. We have analyzed the energy spectra of the 1st and 2nd peaks observed with the Wide Field X-Ray Monitor (WXM) and the French Gamma Telescope (FREGATE). We discuss the origin of the 2nd peak in terms of flux variabilities and timescales. We find that it is most likely part of the prompt emission, and is explained by the long-acting engine model. This feature is similar to some bright X-ray flares detected in the early afterglow phase of bursts observed by the Swift satellite.Comment: 9 pages, 4 figures, Accepted for publication in PAS
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