The Detection of Crystalline Silicates in Ultra-Luminous Infrared Galaxies

Silicates are an important component of interstellar dust and the structure of these grains -- amorphous versus crystalline -- is sensitive to the local physical conditions. We have studied the infrared spectra of a sample of ultra-luminous infrared galaxies. Here, we report the discovery of weak, narrow absorption features at 11, 16, 19, 23, and 28 microns, characteristic of crystalline silicates, superimposed on the broad absorption bands at 10 and 18 microns due to amorphous silicates in a subset of this sample. These features betray the presence of forsterite (Mg_2SiO_4), the magnesium-rich end member of the olivines. Previously, crystalline silicates have only been observed in circumstellar environments. The derived fraction of forsterite to amorphous silicates is typically 0.1 in these ULIRGs. This is much larger than the upper limit for this ratio in the interstellar medium of the Milky Way, 0.01. These results suggest that the timescale for injection of crystalline silicates into the ISM is short in a merger-driven starburst environment (e.g., as compared to the total time to dissipate the gas), pointing towards massive stars as a prominent source of crystalline silicates. Furthermore, amorphization due to cosmic rays, which is thought to be of prime importance for the local ISM, lags in vigorous starburst environments.Comment: 7 pages, 5 figures, accepted for publication in Ap

Renal function and the effects of vericiguat in patients with worsening heart failure with reduced ejection fraction : insights from the VICTORIA (Vericiguat Global Study in Subjects with HFrEF) trial

Aims Vericiguat reduced the primary composite outcome of cardiovascular death or heart failure (HF) hospitalization in patients with worsening HF with reduced ejection fraction (HFrEF) and a lower limit of baseline estimated glomerular filtration rate (eGFR) of 15 mL/min/1.73 m(2). We evaluated the relationship between the efficacy of vericiguat and baseline and subsequent changes in renal function. Methods and results In VICTORIA, core laboratory serum creatinine was measured at baseline (n = 4956) and weeks 16, 32, and 48. Worsening renal function (WRF), defined as an increase >= 0.3 mg/dL in creatinine from baseline to week 16, was assessed via a Cox model with respect to subsequent primary events. Mean age was 69 years, 24% were female, and mean baseline eGFR was 61 mL/min/1.73 m(2). During 48 weeks of treatment, the trajectories in eGFR and creatinine with vericiguat were similar to placebo (P = 0.50 and 0.18). The beneficial effects of vericiguat on the primary outcome were not influenced by baseline eGFR (interaction P = 0.48). WRF occurred in 15% of patients and was associated with worse outcomes (adjusted hazard ratio 1.28, 95% confidence interval 1.11-1.47; P < 0.001), but the beneficial effects of vericiguat on the primary outcome were similar in patients with or without WRF (interaction P = 0.76). Conclusion Renal function trajectories were similar between vericiguat- and placebo-treated patients and the beneficial effects of vericiguat on the primary outcome were consistent across the full range of eGFR and irrespective of WRF.Peer reviewe

Mid-Infrared interferometry of dust around massive evolved stars

We report long-baseline interferometric measurements of circumstellar dust around massive evolved stars with the MIDI instrument on the Very Large Telescope Interferometer and provide spectrally dispersed visibilities in the 8-13 micron wavelength band. We also present diffraction-limited observations at 10.7 micron on the Keck Telescope with baselines up to 8.7 m which explore larger scale structure. We have resolved the dust shells around the late type WC stars WR 106 and WR 95, and the enigmatic NaSt1 (formerly WR 122), suspected to have recently evolved from a Luminous Blue Variable (LBV) stage. For AG Car, the protoypical LBV in our sample, we marginally resolve structure close to the star, distinct from the well-studied detached nebula. The dust shells around the two WC stars show fairly constant size in the 8-13 micron MIDI band, with gaussian half-widths of ~ 25 to 40 mas. The compact dust we detect around NaSt1 and AG Car favors recent or ongoing dust formation. Using the measured visibilities, we build spherically symmetric radiative transfer models of the WC dust shells which enable detailed comparison with existing SED-based models. Our results indicate that the inner radii of the shells are within a few tens of AU from the stars. In addition, our models favor grain size distributions with large (~ 1 micron) dust grains. This proximity of the inner dust to the hot central star emphasizes the difficulty faced by current theories in forming dust in the hostile environment around WR stars. Although we detect no direct evidence for binarity for these objects, dust production in a colliding-wind interface in a binary system is a feasible mechanism in WR systems under these conditions.Comment: 21 pages, 4 tables, 13 figures. Accepted for publication in the Astrophysical Journa

Bolometric luminosity variations in the Luminous Blue Variable AFGL2298

We characterise the variability in the physical properties of the luminous blue variable AFGL2298 between 1989-2008. In conjunction with published data from 1989-2001, we have undertaken a long term (2001-2008) near-IR spectroscopic and photometric observational campaign for this star and utilise a non-LTE model atmosphere code to interpret these data. We find AFGL2298 to have been highly variable during the two decades covered by the observational datasets. Photometric variations of >1.6 mag have been observed in the JHK wavebands; however, these are not accompanied by correlated changes in near-IR colour. Non-LTE model atmosphere analysis of 4 epochs of K band spectroscopy obtained between 2001-7 suggests that the photometric changes were driven by expansion and contraction of the stellar photosphere accompanied by comparatively small changes in the stellar temperature. Unclumped mass loss rates throughout this period were modest and directly comparable to those of other highly luminous LBVs. However, the bolometric luminosity of AFGL2298 appears to have varied by at least a factor of ~2 between 1989-2008, with it being one of the most luminous stars in the Galaxy during maximum. Comparison to other LBVs that have undergone non bolometric luminosity conserving `eruptions' shows such events to be heterogeneous, with AFGL2298 the least extreme example. These results - and the diverse nature of both the quiescent LBVs and associated ejecta - may offer support to the suggestion that more than one physical mechanism is responsible for such behaviour. [ABRIDGED]Comment: 12 pages, 6 figures, accepted for publication in Astronomy and Astrophysic

Effects of Eprosartan on Diastolic Function and Neurohormones in Patients with Hypertension and Diastolic Dysfunction

To compare the effects of an angiotensin receptor blocker(ARB)-based regimen versus a non-ARB based regimen on diastolic function and neurohormones in patients with hypertension and diastolic dysfunction. 97 patients with a systolic blood pressure (SBP) a parts per thousand yen140 mmHg, a left ventricular ejection fraction > 0.50, and echocardiographic evidence of diastolic dysfunction were randomly assignment to open-label treatment with eprosartan (with other anti-hypertensives; n = 47) or other anti-hypertensives alone (n = 50). Echocardiography, including tissue Doppler imaging (TDI), and neurohormones were done at baseline and after 6 months. Mean age was 65 (+/- 10) years and 64% was female. During 6 months of treatment, SBP decreased from 157 +/- 16 to 145 +/- 18 mmHg in the eprosartan group and from 158 +/- 17 to 141 +/- 18 mmHg in the control group (both p <0.001; p = ns between groups). Diastolic function was unaffected in both groups and there was no correlation between changes in SBP and changes in mean TDI (r = -0.06; p = 0.58). Aldosterone levels decreased in the eprosartan group, but other neurohormones remained largely unchanged. Change in SBP was however related to the change in NT-proBNP (r = 0.26; p = 0.019). Lowering blood pressure, either with eprosartan or other anti-hypertensives in hypertensive patients with diastolic dysfunction did not change diastolic function after 6 months of treatment, but was associated with a decrease of NT-proBNP

Short- and long-term haemodynamic consequences of transcatheter closure of atrial septal defect and patent foramen ovale

BACKGROUND: Transcatheter atrial septal defect (ASD) and patent foramen ovale (PFO) closure might have opposite short- and long-term haemodynamic consequences compared with restricted interatrial shunt creation, which recently emerged as a potential treatment modality for patients with heart failure with preserved ejection fraction (HFpEF). Given the opposing approaches of ASD and PFO closure versus shunt creation, we investigated the early and sustained cardiac structural and functional changes following transcatheter ASD or PFO closure. METHODS: In this retrospective study, adult secundum-type ASD and PFO patients with complete echocardiography examinations at baseline and at 1‑day and 1‑year follow-up who also underwent transcatheter closure between 2013 and 2017 at the University Medical Centre Groningen, the Netherlands were included. RESULTS: Thirty-nine patients (mean age 48 ± standard deviation 16 years, 61.5% women) were included. Transcatheter ASD/PFO closure resulted in an early and persistent decrease in right ventricular systolic and diastolic function. Additionally, transcatheter ASD/PFO closure resulted in an early and sustained favourable response of left ventricular (LV) systolic function, but also in deterioration of LV diastolic function with an increase in LV filling pressure (LVFP), as assessed by echocardiography. Age (β = 0.31, p = 0.009) and atrial fibrillation (AF; β = 0.24, p = 0.03) were associated with a sustained increase in LVFP after transcatheter ASD/PFO closure estimated by mean E/e’ ratio (i.e. ratio of mitral peak velocity of early filling to diastolic mitral annular velocity). In subgroup analysis, this was similar for ASD and PFO closure. CONCLUSION: Older patients and patients with AF were predisposed to sustained increases in left-sided filling pressures resembling HFpEF following ASD or PFO closure. Consequently, these findings support the current concept that creating a restricted interatrial shunt might be beneficial, particularly in elderly HFpEF patients with AF. SUPPLEMENTARY INFORMATION: The online version of this article (10.1007/s12471-021-01543-0) contains supplementary material, which is available to authorized users

Randomized, double-blind, placebo-controlled, multicentre pilot study on the effects of empagliflozin on clinical outcomes in patients with acute decompensated heart failure (EMPA-RESPONSE-AHF)

Aims: Inhibition of sodium–glucose co-transporter 2 (SGLT2) reduces the risk of death and heart failure (HF) admissions in patients with chronic HF. However, safety and clinical efficacy of SGLT2 inhibitors in patients with acute decompensated HF are unknown. Methods and results: In this randomized, placebo-controlled, double-blind, parallel group, multicentre pilot study, we randomized 80 acute HF patients with and without diabetes to either empagliflozin 10 mg/day or placebo for 30 days. The primary outcomes were change in visual analogue scale (VAS) dyspnoea score, diuretic response (weight change per 40 mg furosemide), change in N-terminal pro brain natriuretic peptide (NT-proBNP), and length of stay. Secondary outcomes included safety and clinical endpoints. Mean age was 76 years, 33% were female, 47% had de novo HF and median NT-proBNP was 5236 pg/mL. No difference was observed in VAS dyspnoea score, diuretic response, length of stay, or change in NT-proBNP between empagliflozin and placebo. Empagliflozin reduced a combined endpoint of in-hospital worsening HF, rehospitalization for HF or death at 60 days compared with placebo [4 (10%) vs. 13 (33%); P = 0.014]. Urinary output up until day 4 was significantly greater with empagliflozin vs. placebo [difference 3449 (95% confidence interval 578–6321) mL; P < 0.01]. Empagliflozin was safe, well tolerated, and had no adverse effects on blood pressure or renal function. Conclusions: In patients with acute HF, treatment with empagliflozin had no effect on change in VAS dyspnoea, diuretic response, NT-proBNP, and length of hospital stay, but was safe, increased urinary output and reduced a combined endpoint of worsening HF, rehospitalization for HF or death at 60 days

N-Terminal Pro-B-Type Natriuretic Peptide and Clinical Outcomes

OBJECTIVES The purpose of this study was to examine the treatment effect of vericiguat in relation to N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels at randomization. BACKGROUND Vericiguat compared with placebo reduced the primary outcome of cardiovascular death (CVD) or heart failure hospitalization (HFH) in patients with HF with reduced ejection fraction (HFrEF) in the VICTORIA (A Study of Vericiguat in Participants With Heart Failure With Reduced Ejection Fraction) trial. Because an interaction existed between treatment and the primary outcome according to pre-specified quartiles of NT-proBNP at randomization, we examined this further. METHODS This study evaluated the NT-proBNP relationship with the primary outcome in 4,805 of 5,050 patients as a risk-adjusted, tog-transformed continuous variable. Hazard ratios (HRs) and 95% confidence intervals (CIs) are presented. RESULTS Median NT-proBNP was 2,816 pg/ml (25th to 75th percentile: 1,556 to 5,314 pg/ml). The study treatment effect varied across the spectrum of NT-proBNP at randomization (with log(2) transformation, p for interaction = 0.002). A significant association between treatment effects existed in patients with levels 8,000 pg/ml (n = 672), the HR was 1.16 (95% CI: 0.94 to 1.41) for the primary outcome. CONCLUSIONS A reduction in the primary composite endpoint and its CVD and HFH components was observed in patients on vericiguat compared with subjects on placebo with NT-proBNP levels up to 8,000 pg/ml. This provided new insight into the benefit observed in high-risk patients with worsening HFrEF. (C) 2020 The Authors. Published by Elsevier on behalf of the American College of Cardiology Foundation