We present high-fidelity CO(1-0) imaging of molecular gas across the full star-forming disk of M83, using ALMA's 12m, 7m, and TP arrays and the MIRIAD package. The data have a mass sensitivity and ...resolution of 10^4Msun and 40 pc. The full disk coverage shows that the characteristics of molecular gas change radially from the center to outer disk. The molecular gas distribution shows coherent large-scale structures in the inner part, including the central concentration, bar offset ridges, and prominent molecular spiral arms. In the outer disk, the spiral arms appear less spatially coherent, and even flocculent. Massive filamentary gas concentrations are abundant even in the interarm regions. Building up these structures in the interarm regions would require a very long time (~>100Myr). Instead, they must have formed within stellar spiral arms and been released into the interarm regions. For such structures to survive through the dynamical processes, the lifetimes of these structures and their constituent molecules and molecular clouds must be long (~>100Myr). These interarm structures host little or no star formation traced by Halpha. The new map also shows extended CO emission, which likely represents an ensemble of unresolved molecular clouds.
We systematically perform hydrodynamics simulations of 20 km s^-1 converging flows of the warm neutral medium (WNM) to calculate the formation of the cold neutral medium (CNM), especially focusing on ...the mean properties of the multiphase interstellar medium (ISM), such as the average shock front position and the mean density on a 10 pc scale. Our results show that the convergence in those mean properties requires 0.02 pc spatial resolution that resolves the cooling length of the thermally unstable neutral medium (UNM) to follow the dynamical condensation from the WNM to CNM. We also find that two distinct post-shock states appear in the mean properties depending on the amplitude of the upstream WNM density fluctuation (= sqrt(<drho^2>)/rho_0). When the amplitude > 10 %, the interaction between shocks and density inhomogeneity leads to a strong driving of the post-shock turbulence of > 3 km s^-1, which dominates the energy budget in the shock-compressed layer. The turbulence prevents the dynamical condensation by cooling and the following CNM formation, and the CNM mass fraction remains as ~ 45 %. In contrast, when the amplitude <= 10 %, the shock fronts maintain an almost straight geometry and CNM formation efficiently proceeds, resulting in the CNM mass fraction of ~ 70 %. The velocity dispersion is limited to the thermal-instability mediated level of 2 - 3 km s^-1 and the layer is supported by both turbulent and thermal energy equally. We also propose an effective equation of state that models the multiphase ISM formed by the WNM converging flow as a one-phase ISM.
The 21-cm signal in the vicinity of the first stars is expected to reflect properties of the first stars. In this study we pay special attention to tracing the time evolution of the ionizing photons' ...escape fraction, which affects the distribution of neutral hydrogen, by performing radiation hydrodynamics (RHD) simulations resolving dense gas in a halo. We find that the radial profile of 21-cm differential brightness temperature is quite sensitive to the stellar and halo masses, which reflects the time evolution of the escape fraction. In the case of a less massive star, ionizing photons hardly escape from its host halo due to the absorption by dense halo gas, thus an deep 21-cm absorption feature at just outside the halo lasts a long time. Whereas photons from a massive star well working to heat the ambient intergalactic medium turn out to cause a spatially extended 21-cm emission signature. Although individual signals are found to be undetectable with the Square Kilometre Array, our analysis using the results from the RHD simulations indicates that the properties of the first stars are imprinted on the 21-cm global signal: its amplitude depends not only on the cosmic star formation rate density, but also on the typical mass of the first stars due to the stellar-mass-dependent heating rate. Thus, we suggest that the initial mass function of the first stars is an essential factor in understanding the global signal.
Recent radio observations towards nearby galaxies started to map the whole disk and to identify giant molecular clouds (GMCs) even in the regions between galactic spiral structures. Observed ...variations of GMC mass functions in different galactic environment indicates that massive GMCs preferentially reside along galactic spiral structures whereas inter-arm regions have many small GMCs. Based on the phase transition dynamics from magnetized warm neutral medium to molecular clouds, Kobayashi et al. 2017 proposes a semi-analytical evolutionary description for GMC mass functions including cloud-cloud collision (CCC) process. Their results show that CCC is less dominant in shaping the mass function of GMCs compared with the accretion of dense HI gas driven by the propagation of supersonic shock waves. However, their formulation does not take into account the possible enhancement of star formation by CCC. Radio observations within the Milky Way indicate the importance of CCC for the formation of star clusters and massive stars. In this article, we reformulate the time evolution equation largely modified from Kobayashi et al. 2017 so that we additionally compute star formation subsequently taking place in CCC clouds. Our results suggest that, although CCC events between smaller clouds outnumber the ones between massive GMCs, CCC-driven star formation is mostly driven by massive GMCs > 10^5.5 Msun (where Msun is the solar mass). The resultant cumulative CCC-driven star formation may amount to a few 10 percent of the total star formation in the Milky Way and nearby galaxies.
We present \(^{12}\)CO (\(J\) = 2-1), \(^{13}\)CO (\(J\) = 2-1), and C\(^{18}\)O (\(J\) = 2-1) observations toward GMC-8, one of the most massive giant molecular clouds (GMCs) in M33 using ALMA with ...an angular resolution of 0".44 \(\times\) 0".27 (\(\sim\)2 pc \(\times\) 1pc). The earlier studies revealed that its high-mass star formation is inactive in spite of a sufficient molecular reservoir with the total mass of \(\sim\)10\(^{6}\) \(M_{\odot}\). The high-angular resolution data enable us to resolve this peculiar source down to a molecular clump scale. One of the GMC's remarkable features is that a round-shaped gas structure (the "Main cloud" ) extends over \(\sim\)50 pc scale, which is quite different from the other two active star-forming GMCs dominated by remarkable filaments/shells obtained by our series of studies in M33. The fraction of the relatively dense gas traced by the \(^{13}\)CO data with respect to the total molecular mass is only \(\sim\)2 %, suggesting that their spatial structure and the density are not well developed to reach an active star formation. The CO velocity analysis shows that the GMC is composed of a single component as a whole, but we found some local velocity fluctuations in the Main cloud and extra blueshifted components at the outer regions. Comparing the CO with previously published large-scale H I data, we suggest that an external atomic gas flow supplied a sufficient amount of material to grow the GMC up to \(\sim\)10\(^6\) \(M_{\odot}\).
Aim: Impaired lung function is associated with atherosclerotic vascular events. Carotid intima-media thickness (cIMT) is a marker for subclinical atherosclerosis. However, few studies have examined ...the association between lung function and cIMT among never smokers or individuals stratified by age. We investigated the association between lung function and cIMT in the Japanese population.Methods: We conducted a cross-sectional study of 3,716 men and 8,765 women aged 20 years or older living in Miyagi Prefecture, Japan. Lung function was evaluated using forced expiratory volume at 1 s (FEV1) and forced vital capacity (FVC) was measured using spirometry. The maximum common carotid artery was measured using high-resolution B-mode ultrasound. An analysis of covariance was used to assess associations between lung function and cIMT and adjusted for potential confounders. A linear trend test was conducted by scoring the categories from 1 (lowest) to 4 (highest) and entering the score as a continuous term in the regression model.Results: After adjusting for potential confounders including passive smoking, lower FEV1 and FVC were associated with higher cIMT in both men and women (P＜0.001 for linear trend). This association was confirmed even when we restricted our study to never smokers. Furthermore, even when we stratified by age, an inverse association between lung function and cIMT was confirmed in middle-aged (40–64 years) and elderly participants (65–74 years).Conclusions: Lower lung function was associated with higher cIMT in the Japanese population independent of age and smoking. Assessment of atherosclerosis or lung function may be required for individuals with lower lung function or atherosclerosis.
Background: Although fat mass index (FMI) and fat-free mass index (FFMI) affect lung function, FMI and FFMI are not independent of each other, since FMI and FFMI were calculated as fat mass and ...fat-free mass divided by height squared, respectively. We aimed to examine the association of combined FMI and FFMI with lung function.Methods: In this cross-sectional study, lung function was evaluated using forced expiratory volume at 1 s (FEV1) and forced vital capacity (FVC) measured using spirometry. Both FMI and FFMI were classified into sex-specific quartiles (16 groups). Analysis of covariance was used to assess the associations of combined FMI and FFMI with lung function. The trend test was conducted by stratifying the FMI and FFMI, scoring the categories from 1–4 (lowest–highest), and entering the number as a continuous term in the regression model.Results: This study included 3,736 men and 8,821 women aged ≥20 years living in Miyagi Prefecture, Japan. The mean FEV1 was 3.0 (standard deviation SD, 0.7) L for men and 2.3 (SD, 0.5) L for women. The mean FVC was 3.8 (SD, 0.7) L for men and 2.8 (SD, 0.5) L for women. FMI was inversely associated with lung function among all FFMI subgroups in both sexes. Conversely, FFMI was positively associated with lung function in all FMI subgroups in both sexes.Conclusion: Higher FMI was associated with lower lung function independent of FFMI; higher FFMI was associated with higher lung function independent of FMI. Reducing FMI and maintaining FFMI might be important for respiratory health.
Aim: We examined the association between the carotid intima medica thickness (cIMT) and risk factors for atherosclerosis based on the Japan Atherosclerosis Society 2022 Atherosclerosis Prevention ...Guideline. Methods: Using data from the Tohoku Medical Megabank Community-based Cohort Study, we performed a cross-sectional study that enrolled 13,366 participants (age ≥ 20 years) with an analysis of covariance to assess associations between cIMT and risk factors for atherosclerosis. The maximum common carotid artery was measured using high-resolution B-mode ultrasound. Analysis was conducted in the model adjusted for age, sex, smoking status, drinking status, body mass index (BMI), systolic blood pressure (SBP), glycated hemoglobin (HbA1c), high-density lipoprotein-cholesterol (HDL-C), non-high-density lipoprotein-cholesterol (non-HDL-C), and height. Results: In this study cohort, the average age and cIMT were 57.3 (13.8) years and 0.61 (0.13) mm, respectively, which included 3,988 males (29.8%). Males had a higher cIMT than did the females. Age, height, BMI, SBP, HbA1c, and non-HDL-C were positively associated with cIMT. HDL-C was inversely associated with cIMT. Compared with never drinkers, current drinkers (≥ 46.0 g/day) had a significantly decreased cIMT. Conclusions: The cIMT was associated with atherosclerosis risk factors including age, sex, BMI, SBP, HbA1c, non-HDL-C, and HDL-C, and adequate control of risks in high-risk individuals might be required to prevent atherosclerotic cardiovascular diseases.
This Phase II trial was designed to evaluate the safety and efficacy of neoadjuvant oxaliplatin and capecitabine and bevacizumab without radiotherapy in patients with poor-risk rectal cancer.
...Patients with magnetic resonance imaging-defined poor-risk rectal cancer received neoadjuvant oxaliplatin and capecitabine and bevacizumab followed by total mesorectal excision or more extensive surgery.
Between February 2010 and December 2011, 32 patients were enrolled in this study. The completion rate of the scheduled chemotherapy was 91%. Reasons for withdrawal were refusal to continue therapy in two patients and disease progression in one, with two of these three patients not undergoing surgery. Among the 29 patients who completed the scheduled chemotherapy, one refused surgery within 8 weeks after the completion of chemotherapy, which was the period stipulated by the protocol, and another had rectal perforation, requiring urgent laparotomy. As a result, the completion rate of this experimental treatment was 84%. Of the 30 patients who underwent surgery, the R0 resection rate was 90% and a postoperative complication occurred in 43%. A pathological complete response was observed in 13% and good tumor regression was exhibited in 37%.
Neoadjuvant oxaliplatin and capecitabine plus bevacizumab for poor-risk rectal cancer caused a high rate of anastomotic leakage and experienced a case with perforation during chemotherapy, both of which were bevacizumab-related toxicity. Although the short-term results with the completion rate of 84.4% and the pathological complete response rate of 13.3% were satisfactory, we have to reconsider the necessity of bevacizumab in neoadjuvant chemotherapy (UMIN number, 000003507).
Recent radio observations show that the giant molecular cloud (GMC) mass functions noticeably vary across galactic disks. High-resolution magnetohydrodynamics simulations show that multiple episodes ...of compression are required for creating a molecular cloud in the magnetized interstellar medium. In this article, we formulate the evolution equation for the GMC mass function to reproduce the observed profiles, for which multiple compression are driven by the network of expanding shells due to HII regions and supernova remnants. We introduce the cloud-cloud collision (CCC) terms in the evolution equation in contrast to the previous work (Inutsuka et al. 2015). The computed time evolution suggests that the GMC mass function slope is governed by the ratio of GMC formation timescale to its dispersal timescale, and that the CCC effect is limited only in the massive-end of the mass function. In addition, we identify a gas resurrection channel that allows the gas dispersed by massive stars to regenerate GMC populations or to accrete onto the pre-existing GMCs. Our results show that almost all of the dispersed gas contribute to the mass growth of pre-existing GMCs in arm regions whereas less than 60 per cent in inter-arm regions. Our results also predict that GMC mass functions have a single power-law exponent in the mass range < 10^5.5 Msun (where Msun represents the solar mass), which is well characterized by GMC self-growth and dispersal timescales. Measurement of the GMC mass function slope provides a powerful method to constrain those GMC timescales and the gas resurrecting factor in various environment across galactic disks.
