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163 result(s) for "Hayakawa, Takahiro"
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Giant Molecular Clouds in RCW 106 (G333): Galactic Mini-starbursts and Massive Star Formation Induced by Supersonic Cloud–Cloud Collisions
To reveal the origin of the mini-starbursts in the Milky Way, we carried out large-scale CO observations toward the RCW 106 giant molecular cloud (GMC) complex using the NANTEN2 4 m radio telescope operated by Nagoya University. We also analyzed the Mopra Southern Galactic Plane CO survey and Herschel infrared continuum archival data. The RCW 106 GMC complex contains the radial velocity components of −68 km s−1 and −50 km s−1 reported by H. Nguyen et al. (2015). Focusing on the RCW 106 East and West region with the massive star formation having the bright infrared dust emission, we found that these regions have three different velocity components with ∼10 km s−1 differences. The two out of three velocity components show morphological correspondence with the infrared cold dust emission and connect with the bridge feature on a position–velocity diagram. Therefore, two molecular clouds with ∼10 km s−1 differences are likely to be physically associated with massive star-forming regions in the GMC complex. Based on these observational results, we argue that mini-starbursts and massive star/cluster formation in the RCW 106 GMC complex are induced by supersonic cloud–cloud collisions in an agglomerate of molecular gas on the Scutum–Centaurus arm.
The Gamma-Ray Origin of RX J0852.0-4622 Quantifying the Hadronic and Leptonic Components: Further Evidence for the Cosmic-Ray Acceleration in Young Shell-type SNRs
Fukui et al. quantified the hadronic and leptonic gamma-rays in the young TeV gamma-ray shell-type supernova remnant (SNR) RX J1713.7-3946 (RX J1713), and demonstrated that gamma rays are a combination of hadronic and leptonic gamma-ray components with a ratio of ∼6: 4 in gamma-ray counts N g. This discovery, which adopted a new methodology of multi-linear gamma-ray decomposition, was the first quantification of the two gamma-ray components. In the present work, we applied the same methodology to another TeV gamma-ray shell-type SNR RX J0852.0-4622 (RXJ0852) in 3D space characterized by (the interstellar proton column density N p)-(the nonthermal X-ray count N x)-[N g], and quantified the hadronic and leptonic gamma-ray components as having a ratio of ∼5:5 in N g. The present work adopted the fitting of two/three flat planes in 3D space instead of a single flat plane, which allowed suppression of the fitting errors. This quantification indicates that hadronic and leptonic gamma-rays are of the same order of magnitude in these two core-collapse SNRs, verifying the significant hadronic gamma-ray components. We argue that the target interstellar protons, in particular their spatial distribution, are essential in any attempts to identify the type of particles responsible for gamma-ray emission. The present results confirm that cosmic-ray (CR) energy ≲100 TeV is compatible with a scheme in which SNRs are the dominant source of these Galactic CRs.
Neonatal factors related to center variation in the incidence of late-onset circulatory collapse in extremely preterm infants
Although late-onset circulatory collapse (LCC) is widely recognized in Japan, its etiology and the reason for center variation in its incidence remain unclear. This study's objectives were to identify the perinatal and neonatal factors related to LCC and to estimate the factors related to the center variation in the incidence of LCC. Extremely preterm infants born between 2008 and 2012 who were registered in the database of the Neonatal Research Network, Japan were retrospectively analyzed. LCC was defined as a clinical diagnosis of LCC and the administration of steroids. We first identified the factors that were significantly related to LCC. We then examined the cause of the center variation in the incidence of LCC, using the standardized incidence ratios (SIRs) of LCC and individual factors. The factors significantly associated with LCC included low gestational age (odds ratio [OR]: 1.13), small for date (OR: 1.43), male sex (OR: 1.26), antenatal steroid use (OR: 1.19), respiratory distress syndrome (OR: 1.25), chronic lung disease at 36 weeks (OR: 1.16), periventricular leukomalacia (PVL) (OR: 2.57), necrotizing enterocolitis (OR: 0.59), retinopathy of prematurity (ROP) (OR: 1.73), high-frequency oscillating ventilation (HFOV) use (OR: 1.31), parenteral nutrition (OR: 1.38), and red blood cell (RBC) transfusion (OR: 1.94). The SIR of LCC ranged from 0.05 to 2.94, and was positively correlated with SIRs of PVL, ROP, HFOV use and RBC transfusion. PVL, ROP, HFOV use and RBC transfusion were found to be correlated with the center variation in the incidence of LCC.
Fulminant type 1 diabetes mellitus associated with Coxsackievirus type B1 infection during pregnancy: a case report
Background Fulminant type 1 diabetes is characterized by an intrinsic insulin deficiency resulting from the severe destruction of pancreatic β cells and it rapidly leads to ketoacidosis. However, the association between fulminant type 1 diabetes in pregnancy and specific viral infections has not been reported. Case presentation The patient in this study was a 31-year-old Japanese woman, and at 30 weeks of pregnancy she was admitted with marked fatigue. Fetal bradycardia was noted, and the child was delivered by emergency cesarean section but was stillborn. The maternal blood sugar level was high (427 mg/dL), but the glycated hemoglobin value was 6.2%; therefore, fulminant type 1 diabetes was suspected. Serum antibody testing confirmed a Coxsackievirus B1 infection. The patient in this case had fulminant type 1 diabetes in pregnancy associated with Coxsackievirus B1. Conclusion This case highlights that fulminant type 1 diabetes in pregnancy may be associated with Coxsackievirus B1 infection.
Impact of pre‐existing interstitial lung abnormal shadow on lung injury development and severity in patients of non‐small cell lung cancer treated with osimertinib
Background First‐generation epidermal growth factor receptor‐tyrosine kinase inhibitor (EGFR‐TKI) sometimes causes lung injury, thereby affecting survival. Although pre‐existing interstitial lung abnormal shadow (pre‐ILS) increases the risk of lung injury by EGFR‐TKIs, its impact on osimertinib, a third‐generation EGFR‐TKI, remains unknown. Patients and Methods This retrospective cohort study consecutively enrolled patients of EGFR‐mutated non‐small cell lung cancer treated with osimertinib. Computed tomography images were obtained and evaluated independently by three pulmonologists in a blinded manner. Factors associated with lung injury were assessed using a logistic regression model. Survival curves were calculated by the Kaplan–Meier method and compared using a log‐rank test. Results Of the 195 patients, 40 had pre‐ILS, and 21 (8 with and 13 without pre‐ILS) developed lung injury during the observation period. Multivariate analysis revealed that pre‐ILS was independently associated with lung injury (odds ratio, 3.1; 95% confidence interval [CI], 1.1–8.2; p = 0.025). Severe (≥Grade 3) lung injury was observed in eight (4.1%) patients, of whom, two (5%) and six (3.9%) had and did not have pre‐ILS (p = 0.67), respectively. Grade 5 lung injury was not observed, and survival curves were similar between the patients who developed lung injury and those who did not (median 11 vs. 12 months; hazard ratio, 1.2; 95% CI, 0.56–2.7; p = 0.60). Conclusions Pre‐ILS increased the risk of lung injury in patients of non‐small cell lung cancer treated with osimertinib, while the severity of lung injury was not clearly affected by the presence of pre‐ILS. Although pre‐existing interstitial lung abnormal (pre‐ILS) shadow has been known to be a risk factor of lung injury by EGFR‐TKIs, data on osimertinib are lacking. Current results demonstrated that pre‐ILS increases the risk of lung injury (odds ratio, 3.1; 95% confidence interval, 1.1–8.2; p = 0.025) in the treatment with osimertinib. Notably, the incidence of grade ≥3 was similar between patients with and without pre‐ILS, which was 5% and 3.9%, respectively. The overall survival was similar for patients who developed lung injury and those who did not. However, we still need to be cautious during treatment with osimertinib in patients with pre‐ILS; further studies are warranted in this field.
Ex-vivo Imaging of Glial Energy Metabolism in the Neonatal Mouse Brain during Convulsive Seizures with Intranasal Radiotracer Administration
Purpose In this study, we examined changes in glial energy metabolism in neonatal mouse brain images obtained under pathological conditions following intranasal administration of the radiotracer [2- 14 C]acetate. Procedures [2- 14 C]acetate was administered via the mouse nasal cavity, after which autoradiograms of the brain of 7-day-old mice were obtained. Radio thin-layer chromatography was applied for metabolite analysis of brain radioactivity. We also compared brain uptake of [2- 14 C]acetate when administrated intranasally and intravenously in 3-week-old mice. To confirm selective uptake by glial cells, [2- 14 C]acetate was injected into the nasal cavity of mice injected with a glial toxin in the brain. Pentylenetetrazole (PTZ) was applied to induce seizures. Results Intranasally administered [2- 14 C]acetate was rapidly incorporated into the brains of 7-day-old mice, reaching its highest uptake level 20 min after administration. After 20 min of intranasal [2- 14 C]acetate administration, glutamate and glutamine accounted for 32 ± 2.5% and 30 ± 3.4% of total brain radioactivity, respectively. There was no difference in the radioactivity distribution in the brain between intranasal and intravenous administration, except in the ventral olfactory bulb in 3-week-old mice. Microinjection of the glial-specific toxin fluorocitrate reduced the accumulation of radioactivity in the brain by 60% following intranasal administration in 3-week-old mice. The uptake of [2- 14 C]acetate in the brains of 7-day-old mice significantly decreased 30 min after systemic PTZ administration, suggesting a decrease in energy metabolism in glial cells during seizures. Conclusions Quantitative images of biological functions in the neonatal mouse brain can be obtained by intranasal administration. This technique allowed the observation of a decrease in acetate uptake associated with convulsive seizures. The results of this study could be applied to the imaging of biological brain functions and research on neurological disorders using labeled probes in neonatal mice.
Magnetization Curve of Second Layer Anti-Ferromagnetic Solid 3He on Graphite
Two dimensional anti-ferromagnetic solid 3 He on graphite in the so called 4/7 phase is a highly frustrated quantum spin system and its ground state is considered to be a gapless spin liquid. To investigate the detailed magnetic behavior, the magnetization curve has been measured below 1 mK in high magnetic fields, by use of NMR over a wide frequency range up to 84 MHz. The magnetization of the 4/7 phase seems to have a plateau at half the saturation magnetization, which is not inconsistent with results obtained with a double gradient Faraday magnetometer.
ASTE Submillimeter observations of a YSO condensation in Cederblad 110
Outflow-cloud interaction is an important issue in discussions about star formation in clusters because it could generate turbulence and restrain star formation activities, as well as it causes outflow-triggered star formation.
Submillimeter-wave observations of outflow and envelope around the low mass protostar IRAS 13036-7644
The interaction between molecular outflow from a protostar and ambient molecular cloud would play an important role in dissipating circumstellar envelope, changing chemical composition, and triggering next generation star formation. In order to investigate the interaction in submillimeter wavelength, we have made line observations toward the low mass protostar IRAS 13036-7644 (Class 0/I) in the Cha II dark cloud. Although millimeter observations found CO outflow and evidence of mass infall toward the protostar (e.g. Lehtinen 1997), no submillimeter observation has been reported so far.
Dust-to-neutral gas ratio of the intermediate and high velocity HI clouds derived based on the sub-mm dust emission for the whole sky
We derived the dust-to-HI ratio of the intermediate-velocity clouds (IVCs), the high-velocity clouds (HVCs), and the local HI gas, by carrying out a multiple-regression analysis of the 21cm HI emission combined with the sub-mm dust optical depth. The method covers over 80 per cent of the sky contiguously at a resolution of 47arcmin and is distinguished from the absorption line measurements toward bright galaxies and stars covering a tiny fraction of the sky. Major results include that the ratio of the IVCs is in a range of 0.1--1.5 with a mode at 0.6 (relative to the solar-neighbourhood value, likewise below) and that a significant fraction, ~20 per cent, of the IVCs include dust-poor gas with a ratio of <0.5. It is confirmed that 50 per cent of the HVC Complex C has a ratio of <0.3, and that the Magellanic Stream has the lowest ratio with a mode at ~0.1. The results prove that some IVCs have low metallicity gas, contrary to the previous absorption line measurements. Considering that the recent works show that the IVCs are interacting and exchanging momentum with the high-metallicity Galactic halo gas, we argue that the high-metallicity gas contaminates a significant fraction of the IVCs. Accordingly, we argue that the IVCs include a significant fraction of the low metallicity gas supplied from outside the Galaxy as an alternative to the Galactic-fountain model.