A Molecular Line Observation toward Massive Clumps Associated with Infrared Dark Clouds

We have surveyed the N2H+ J=1-0, HC3N J=5-4, CCS J_N=4_3-3_2, NH3 (J, K) = (1, 1), (2, 2), (3, 3), and CH3OH J=7-6 lines toward the 55 massive clumps associated with infrared dark clouds by using the Nobeyama Radio Observatory 45 m telescope and the Atacama Submillimeter Telescope Experiment 10 m telescope. The N2H+, HC3N, and NH3 lines are detected toward most of the objects. On the other hand, the CCS emission is detected toward none of the objects. The [CCS]/[N2H+] ratios are found to be mostly lower than unity even in the Spitzer 24 micron dark objects. This suggests that most of the massive clumps are chemically more evolved than the low-mass starless cores. The CH3OH emission is detected toward 18 out of 55 objects. All the CH3OH-detected objects are associated with the Spitzer 24 micron sources, suggesting that star formation has already started in all the CH3OH-detected objects. The velocity widths of the CH3OH J_K=7_0-6_0 A+ and 7_{-1}-6_{-1} E lines are broader than those of N2H+ J=1-0. The CH3OH J_K=7_0-6_0 A+ and 7_{-1}-6_{-1} E lines tend to have broader linewidth in the MSX dark objects than in the others, the former being younger or less luminous than the latter. The origin of the broad emission is discussed in terms of the interaction between an outflow and an ambient cloud.Comment: Accepted to Ap

Monoclinic and Correlated Metal Phase in VO_2 as Evidence of the Mott Transition: Coherent Phonon Analysis

In femtosecond pump-probe measurements, the appearance of coherent phonon oscillations at 4.5 THz and 6.0 THz indicating the rutile metal phase of VO_2 does not occur simultaneously with the first-order metal-insulator transition (MIT) near 68^oC. The monoclinic and correlated metal(MCM) phase between the MIT and the structural phase transition (SPT) is generated by a photo-assisted hole excitation which is evidence of the Mott transition. The SPT between the MCM phase and the rutile metal phase occurs due to subsequent Joule heating. The MCM phase can be regarded as an intermediate non-equilibrium state.Comment: 4 pages, 2 figure

The impact of cardiac comorbidity sequence at baseline and mortality risk in type 2 Diabetes Mellitus: a retrospective population-based cohort study

Introduction: The presence of multiple comorbidities increases the risk of all-cause mortality, but the effects of the comorbidity sequence before the baseline date on mortality remain unexplored. This study investigated the relationship between coronary heart disease (CHD), atrial fibrillation (AF) and heart failure (HF) through their sequence of development and the effect on all-cause mortality risk in type 2 diabetes mellitus. Methods: This study included patients with type 2 diabetes mellitus prescribed antidiabetic/cardiovascular medications in public hospitals of Hong Kong between 1 January 2009 and 31 December 2009, with follow-up until death or 31 December 2019. The Cox regression was used to identify comorbidity sequences predicting all-cause mortality in patients with different medication subgroups. Results: A total of 249,291 patients (age: 66.0 ± 12.4 years, 47.4% male) were included. At baseline, 7564, 10,900 and 25,589 patients had AF, HF and CHD, respectively. Over follow-up (3524 ± 1218 days), 85,870 patients died (mortality rate: 35.7 per 1000 person-years). Sulphonylurea users with CHD developing later and insulin users with CHD developing earlier in the disease course had lower mortality risks. Amongst insulin users with two of the three comorbidities, those with CHD with preceding AF (hazard ratio (HR): 3.06, 95% CI: [2.60–3.61], p < 0.001) or HF (HR: 3.84 [3.47–4.24], p < 0.001) had a higher mortality. In users of lipid-lowering agents with all three comorbidities, those with preceding AF had a higher risk of mortality (AF-CHD-HF: HR: 3.22, [2.24–4.61], p < 0.001; AF-HF-CHD: HR: 3.71, [2.66–5.16], p < 0.001). Conclusions: The sequence of comorbidity development affects the risk of all-cause mortality to varying degrees in diabetic patients on different antidiabetic/cardiovascular medications

Risk stratification of cardiac arrhythmias and sudden cardiac death in type 2 diabetes mellitus patients receiving insulin therapy: A population-based cohort study

Introduction Metabolic abnormalities may exacerbate the risk of adverse outcomes in patients with type 2 diabetes mellitus. The present study aims to assess the predictive value of HbA1c and lipid variability on the risks of sudden cardiac death (SCD) and incident atrial fibrillation (AF). Methods The retrospective observational study consists of type 2 diabetic patients prescribed with insulin, who went to publicly funded clinics and hospitals in Hong Kong between January 1, 2009 and December 31, 2009. Variability in total cholesterol, low-density lipoprotein-cholesterol (LDL-C), high-density lipoprotein-cholesterol (HDL-C), triglyceride, and HbA1c were assessed through their SD and coefficient of variation. The primary outcomes were incident (1) ventricular tachycardia/ventricular fibrillation, actual or aborted SCD and (2) AF. Results A total of 23 329 patients (mean ± SD age: 64 ± 14 years old; 51% male; mean HbA1c 8.6 ± 1.3%) were included. On multivariable analysis, HbA1c, total cholesterol, LDL-C and triglyceride variability were found to be predictors of SCD (p < .05). Conclusion HbA1c and lipid variability were predictive of SCD. Therefore, poor glucose control and variability in lipid parameters in diabetic patients are associated with aborted or actual SCD. These observations suggest the need to re-evaluate the extent of glycemic control required for outcome optimization

C+^+ detection of warm dark gas in diffuse clouds

We present the first results of the Herschel open time key program, Galactic Observations of Terahertz C$^+$ (GOT C+) survey of the [CII] fine-structure line at 1.9 THz (158 microns) using the HIFI instrument on Herschel. We detected 146 interstellar clouds along sixteen lines-of-sight towards the inner Galaxy. We also acquired HI and CO isotopologue data along each line-of-sight for analysis of the physical conditions in these clouds. Here we analyze 29 diffuse clouds (A$_{V}$ < 1.3 mag.) in this sample characterized by having [CII] and HI emission, but no detectable CO. We find that [CII] emission is generally stronger than expected for diffuse atomic clouds, and in a number of sources is much stronger than anticipated based on their HI column density. We show that excess [CII] emission in these clouds is best explained by the presence of a significant diffuse warm H$_2$, dark gas, component. This first [CII] 158 micron detection of warm dark gas demonstrates the value of this tracer for mapping this gas throughout the Milky Way and in galaxies.Comment: To be published in A&A HIFI Special Editio

The Different Structures of the Two Classes of Starless Cores

We describe a model for the thermal and dynamical equilibrium of starless cores that includes the radiative transfer of the gas and dust and simple CO chemistry. The model shows that the structure and behavior of the cores is significantly different depending on whether the central density is either above or below about 10^5 cm-3. This density is significant as the critical density for gas cooling by gas-dust collisions and also as the critical density for dynamical stability, given the typical properties of the starless cores. The starless cores thus divide into two classes that we refer to as thermally super-critical and thermally sub-critical.This two-class distinction allows an improved interpretation of the different observational data of starless cores within a single model.Comment: ApJ in pres

Initiation of warfarin is associated with decreased mortality in patients with infective endocarditis: A population-based cohort study.

The use of warfarin to prevent thromboembolism in patients with infective endocarditis (IE) remains controversial due to potentially increased bleeding risks. Population-based retrospective cohort study. Patients aged 18 or older and diagnosed with IE in Hong Kong between January 1st, 1997 and August 31st, 2020 were included. Patients with use of any anticoagulant 30 days before IE diagnosis were excluded. Patients initiated on warfarin within 14 days of IE diagnosis and patients without warfarin use were matched for baseline characteristics using 1:1 propensity score matching. Warfarin use within 14 days of IE diagnosis. Patients were followed up to 90 days for the outcomes of ischemic stroke, all-cause mortality, intracranial hemorrhage, and gastrointestinal bleeding. Cox regression was used to determine hazard ratios (HRs) [95 % confidence intervals (CIs)] between treatment groups. Fine-Gray competing risk regression with all-cause mortality as the competing event was performed as a sensitivity analysis. In addition to 90-day analyses, landmark analyses were performed at 30 days of follow-up. The matched cohort consisted of 675 warfarin users (57.0 % male, age 59 ± 16 years) and 675 warfarin non-users (53.5 % male, age 61 ± 19 years). Warfarin users had a 50 % decreased 90-day risk in all-cause mortality (HR:0.50 [0.39-0.65]), without significantly different 90-day risks of ischemic stroke (HR:1.04 [0.70-1.53]), intracranial hemorrhage (HR:1.25 [0.77-2.04]), and gastrointestinal bleeding (HR:1.04 [0.60-1.78]). Thirty-day landmark analysis showed similar results. Competing risk regression showed significantly higher 30-day cumulative incidence of intracranial hemorrhage in warfarin users (sub-HR:3.34 [1.34-8.31]), but not at 90-day (sub-HR:1.63 [0.95-2.81]). Results from Fine-Gray regression were otherwise congruent with those from Cox regression. Warfarin initiated within 14 days of IE diagnosis was associated with significantly decreased risks of mortality but higher risks of intracranial hemorrhage, with similar risks of ischemic stroke and gastrointestinal bleeding, compared with non-use of warfarin with 14 days of IE diagnosis. Question: Is warfarin, initiated within 14 days of a diagnosis of infective endocarditis (IE), efficacious and safe? In this propensity score-matched, population-based, prospective cohort study from Hong Kong, warfarin use within 14 days of IE diagnosis was associated with a 50 % decrease in the risk of all-cause mortality, albeit with higher risk of intracranial hemorrhage, and without significant differences in the risk of ischaemic stroke and gastrointestinal bleeding. Meaning: In patients with IE, warfarin use within 14 days of diagnosis may have mortality benefits, despite increased risks of intracranial hemorrhage. [Abstract copyright: Copyright © 2023. Published by Elsevier Ltd.

Water and methanol in low-mass protostellar outflows: gas-phase synthesis, ice sputtering and destruction

Water in outflows from protostars originates either as a result of gas-phase synthesis from atomic oxygen at T ≳ 200 K, or from sputtered ice mantles containing water ice. We aim to quantify the contribution of the two mechanisms that lead to water in outflows, by comparing observations of gas-phase water to methanol (a grain surface product) towards three low-mass protostars in NGC 1333. In doing so, we also quantify the amount of methanol destroyed in outflows. To do this, we make use of James Clerk Maxwell Telescope and Herschel-Heterodyne Instrument for the Far-Infrared data of H2O, CH3OH and CO emission lines and compare them to RADEX non-local thermodynamic equilibrium excitation simulations. We find up to one order of magnitude decrease in the column density ratio of CH3OH over H2O as the velocity increases in the line wings up to ∼15 km s−1. An independent decrease in X(CH3OH) with respect to CO of up to one order of magnitude is also found in these objects. We conclude that gas-phase formation of H2O must be active at high velocities (above 10 km s−1 relative to the source velocity) to re-form the water destroyed during sputtering. In addition, the transition from sputtered water at low velocities to form water at high velocities must be gradual. We place an upper limit of two orders of magnitude on the destruction of methanol by sputtering effects