| 1. |
- Amada, Kei, et al.
(författare)
-
Discovery of SiO masers in the Water Fountain source, IRAS 16552-3050
- 2022
-
Ingår i: Proceedings of the International Astronomical Union. - 1743-9213 .- 1743-9221. ; 18, s. 359-361
-
Konferensbidrag (refereegranskat)abstract
- We report new detections of SiO ν = 1 and ν = 2 J = 1 → 0 masers in the water fountain source IRAS 16552-3050, which was observed with the Nobeyama 45 m telescope from March 2021 to April 2023. Water fountains are evolved stars whose H2O maser spectra trace high-velocity outflows of >100 Km s-. This is the second known case of SiO masers in a water fountain, after their prototypical source, W 43A. The line-of-sight velocity of the SiO masers are blue-shifted by ∼25 km s-1 from the systemic velocity. This velocity offset imply that the SiO masers are associated with nozzle structure formed by a jet penetrating the circumstellar envelope, and that new gas blobs of the jet erupted recently. Thus, the SiO masers imply this star to be in a new evolutionary stage.
|
|
| 2. |
- Imai, Hiroshi, et al.
(författare)
-
FLASHING: Project overview
- 2023
-
Ingår i: Publication of the Astronomical Society of Japan. - 2053-051X .- 0004-6264. ; 75:6, s. 1183-1213
-
Tidskriftsartikel (refereegranskat)abstract
- This paper describes an overview of the FLASHING (Finest Legacy Acquisitions of SiO-/H2O-maser Ignitions by the Nobeyama Generation) project promoted using the 45 m telescope of Nobeyama Radio Observatory, which aims to intensively monitor H2O (at 22 GHz) and SiO (at 43 GHz) masers associated with so-called "water fountain" sources. Here we show scientific results based on the data taken in the first five seasons of FLASHING, from 2018 December to 2023 April. We show the evolution of the H2O maser spectra, discovering new spectral components that break the record of the jet's top speed and/or systematic velocity drifts in the spectrum indicating acceleration or deceleration of the maser gas clumps. For the 43 GHz SiO maser emission, we newly detect it in one source and find that it is no longer present in another source. This implies that the jets from these water fountains can be accelerated or decelerated, and show how circumstellar envelopes are destroyed.
|
|
| 3. |
- Imai, Hiroshi, et al.
(författare)
-
Water Fountain Sources Monitored in FLASHING
- 2022
-
Ingår i: Proceedings of the International Astronomical Union. - 1743-9213 .- 1743-9221. ; 18, s. 333-337
-
Konferensbidrag (refereegranskat)abstract
- We have investigated the spectral evolutions of H2O and SiO masers associated with 12 water fountain sources in our FLASHING (Finest Legacy Acquisitions of SiO-/H2O-maser Ignitions by Nobeyama Generation) project. Our monitoring observations have been conducted using the Nobeyama 45 m telescope every 2 weeks-2 months since 2018 December except during summer seasons. We have found new extremely high velocity H2O maser components, breaking the records of jet speeds in this type of sources. Systematic line-of-sight velocity drifts of the H2O maser spectral peaks have also been found, indicating acceleration of the entrained material hosting the masers around the jet. Moreover, by comparing with previous spectral data, we can find decadal growths/decays of H2O maser emission. Possible periodic variations of the maser spectra are further being inspected in order to explore the periodicity of the central stellar system (a pulsating star or a binary). Thus we expect to see the real-time evolution/devolutions of the water fountains over decades.
|
|
| 4. |
- Ohshima, Mitsuhiro, et al.
(författare)
-
Fibroblast VEGF-receptor 1 expression as molecular target in periodontitis
- 2016
-
Ingår i: Journal of Clinical Periodontology. - : Wiley. - 0303-6979 .- 1600-051X. ; 43:2, s. 128-137
-
Tidskriftsartikel (refereegranskat)abstract
- AimDegradation of extracellular matrices is an integral part in periodontitis. For antagonizing this pathophysiological mechanism, we aimed at identifying gene expression profiles in disease progression contributing periodontitis-associated fibroblasts (PAFs) versus normal gingival fibroblasts to determine their molecular repertoire, and exploit it for therapeutic intervention. Materials and MethodsApplying an exploratory analysis using a small number of microarrays in combination with a three dimensional (3D) invitro culture model that incorporates some aspects of periodontitis, PAFs were initially characterized by gene-expression analyses, followed by targeted gene down-regulation and pharmacological intervention in vitro. Further, immunohistochemistry was applied for phosphorylation analyses in tissue specimens. ResultsPAFs were characterized by 42 genes being commonly up-regulated >1.5-fold, and by five genes that were concordantly down-regulated (<0.7-fold). Expression of vascular endothelial growth factor (VEGF)-receptor 1 (Flt-1) was highly enhanced, and was thus further explored in invitro culture models of periodontal fibroblasts without accounting for the microbiome. Phosphorylation of the VEGF-receptor 1 was enhanced in PAFs. Receptor inhibition by a specific VEGF-receptor inhibitor or intrinsic down-regulation by RNAi of the VEGF-receptor kinase in 3D gel cultures resulted in significant reduction in collagen degradation associated with increased tissue inhibitor of metalloproteinase expression, suggesting that Flt-1 may contribute to periodontitis. ConclusionBased on the finding that VEGF-receptor kinase inhibition impaired collagen degradation pathways, Flt-1 may represent a candidate for therapeutic approaches in periodontitis.
|
|
