60 research outputs found

    北海道でホソスゲを再発見する

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    ALMA CO Observations of a Giant Molecular Cloud in M33: Evidence for High-Mass Star Formation Triggered by Cloud-Cloud Collisions

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    We report the first evidence for high-mass star formation triggered by collisions of molecular clouds in M33. Using the Atacama Large Millimeter/submillimeter Array, we spatially resolved filamentary structures of giant molecular cloud 37 in M33 using 12^{12}CO(JJ = 2-1), 13^{13}CO(JJ = 2-1), and C18^{18}O(JJ = 2-1) line emission at a spatial resolution of \sim2 pc. There are two individual molecular clouds with a systematic velocity difference of \sim6 km s1^{-1}. Three continuum sources representing up to \sim10 high-mass stars with the spectral types of B0V-O7.5V are embedded within the densest parts of molecular clouds bright in the C18^{18}O(JJ = 2-1) line emission. The two molecular clouds show a complementary spatial distribution with a spatial displacement of \sim6.2 pc, and show a V-shaped structure in the position-velocity diagram. These observational features traced by CO and its isotopes are consistent with those in high-mass star-forming regions created by cloud-cloud collisions in the Galactic and Magellanic Cloud HII regions. Our new finding in M33 indicates that the cloud-cloud collision is a promising process to trigger high-mass star formation in the Local Group.Comment: 13 pages, 10 figures, 1 table, accepted for publication in PAS

    Identification of minimal sequence for HIV-1 fusion inhibitors.

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    Emergence of multi-drug resistant HIV-1 is a serious problem for AIDS treatment. Recently, the virus-cell membrane fusion process has been identified as a promising target for the development of novel drugs against these resistant variants. In this study, we identified a 29-residue peptide fusion inhibitor, SC29EK, which shows activity comparable to the previously reported inhibitor SC35EK. Some residues in SC29EK not required for interaction with virus gp41 heptad repeat 1 (HR1) were replaced with a non-proteinogenic amino acid, 2-aminoisobutyric acid (Aib), to stabilize the alpha-helix structure and to provide resistance to peptidases
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