| 1. |
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| 2. |
- Korenblik, R., et al.
(författare)
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Dragon 1 Protocol Manuscript : Training, Accreditation, Implementation and Safety Evaluation of Portal and Hepatic Vein Embolization (PVE/HVE) to Accelerate Future Liver Remnant (FLR) Hypertrophy
- 2022
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Ingår i: Cardiovascular and Interventional Radiology. - : Springer. - 0174-1551 .- 1432-086X. ; 45, s. 1391-1398
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Tidskriftsartikel (refereegranskat)abstract
- Study Purpose The DRAGON 1 trial aims to assess training, implementation, safety and feasibility of combined portal- and hepatic-vein embolization (PVE/HVE) to accelerate future liver remnant (FLR) hypertrophy in patients with borderline resectable colorectal cancer liver metastases. Methods The DRAGON 1 trial is a worldwide multicenter prospective single arm trial. The primary endpoint is a composite of the safety of PVE/HVE, 90-day mortality, and one year accrual monitoring of each participating center. Secondary endpoints include: feasibility of resection, the used PVE and HVE techniques, FLR-hypertrophy, liver function (subset of centers), overall survival, and disease-free survival. All complications after the PVE/HVE procedure are documented. Liver volumes will be measured at week 1 and if applicable at week 3 and 6 after PVE/HVE and follow-up visits will be held at 1, 3, 6, and 12 months after the resection. Results Not applicable. Conclusion DRAGON 1 is a prospective trial to assess the safety and feasibility of PVE/HVE. Participating study centers will be trained, and procedures standardized using Work Instructions (WI) to prepare for the DRAGON 2 randomized controlled trial. Outcomes should reveal the accrual potential of centers, safety profile of combined PVE/HVE and the effect of FLR-hypertrophy induction by PVE/HVE in patients with CRLM and a small FLR.
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| 3. |
- de Blok, W.J.G., et al.
(författare)
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an overview of the MHONGOOSE survey: Observing nearby galaxies with MeerKAT
- 2016
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Ingår i: Proceedings of Science. - 1824-8039.
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Konferensbidrag (refereegranskat)abstract
- MHONGOOSE is a deep survey of the neutral hydrogen distribution in a representative sample of 30 nearby disk and dwarf galaxies with H I masses from ∼ 106 to ∼ 1011 M, and luminosities from MR ∼ 12 to MR ∼ −22. The sample is selected to uniformly cover the available range in log(MHI). Our extremely deep observations, down to H I column density limits of well below 1018 cm−2 — or a few hundred times fainter than the typical H I disks in galaxies — will directly detect the effects of cold accretion from the intergalactic medium and the links with the cosmic web. These observations will be the first ever to probe the very low-column density neutral gas in galaxies at these high resolutions. Combination with data at other wavelengths, most of it already available, will enable accurate modeling of the properties and evolution of the mass components in these galaxies and link these with the effects of environment, dark matter distribution, and other fundamental properties such as halo mass and angular momentum. MHONGOOSE can already start addressing some of the SKA-1 science goals and will provide a comprehensive inventory of the processes driving the transformation and evolution of galaxies in the nearby universe at high resolution and over 5 orders of magnitude in column density. It will be a Nearby Galaxies Legacy Survey that will be unsurpassed until the advent of the SKA, and can serve as a highly visible, lasting statement of MeerKAT’s capabilities.
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| 4. |
- Danilovich, T., et al.
(författare)
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ATOMIUM: halide molecules around the S-type AGB star W Aquilae
- 2021
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 655
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Tidskriftsartikel (refereegranskat)abstract
- Context. S-type asymptotic giant branch (AGB) stars are thought to be intermediates in the evolution of oxygen- to carbon-rich AGB stars. The chemical compositions of their circumstellar envelopes are also intermediate but have not been studied in as much detail as their carbon- and oxygen-rich counterparts. W Aql is a nearby S-type star, with well-known circumstellar parameters, making it an ideal object for in-depth study of less common molecules. Aims. We aim to determine the abundances of AlCl and AlF from rotational lines, which have been observed for the first time towards an S-type AGB star. In combination with models based on PACS observations, we aim to update our chemical kinetics network based on these results. Methods. We analyse ALMA observations towards W Aql of AlCl in the ground and first two vibrationally excited states and AlF in the ground vibrational state. Using radiative transfer models, we determine the abundances and spatial abundance distributions of (AlCl)-Cl-35, (AlCl)-Cl-37, and AlF. We also model HCl and HF emission and compare these models to PACS spectra to constrain the abundances of these species. Results. AlCl is found in clumps very close to the star, with emission confined within 0 ''.1 of the star. AlF emission is more extended, with faint emission extending 0 ''.2 to 0 ''.6 from the continuum peak. We find peak abundances, relative to H-2, of 1.7 x 10(-7) for (AlCl)-Cl-35, 7 x 10(-8) for (AlCl)-Cl-37, and 1 x 10(-7) for AlF. From the PACS spectra, we find abundances of 9.7 x 10(-8) and <= 10(-8), relative to H-2, for HCl and HF, respectively. Conclusions. The AlF abundance exceeds the solar F abundance, indicating that fluorine synthesised in the AGB star has already been dredged up to the surface of the star and ejected into the circumstellar envelope. From our analysis of chemical reactions in the wind, we conclude that AlF may participate in the dust formation process, but we cannot fully explain the rapid depletion of AlCl seen in the wind.
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| 5. |
- Montargès, M., et al.
(författare)
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The VLT/SPHERE view of the A TOMIUM cool evolved star sample: I. Overview: Sample characterization through polarization analysis
- 2023
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 671
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Tidskriftsartikel (refereegranskat)abstract
- Context. Low- and intermediate-mass asymptotic giant stars and massive red supergiant stars are important contributors to the chemical enrichment of the Universe. They are among the most efficient dust factories of the Galaxy, harboring chemically rich circumstellar environments. Yet, the processes that lead to dust formation or the large-scale shaping of the mass loss still escape attempts at modeling. Aims. Through the ATOMIUM project, we aim to present a consistent view of a sample of 17 nearby cool evolved stars. Our goals are to unveil the dust-nucleation sites and morphologies of the circumstellar envelope of such stars and to probe ambient environments with various conditions. This will further enhance our understanding of the roles of stellar convection and pulsations, and that of companions in shaping the dusty circumstellar medium. Methods. Here we present and analyze VLT/SPHERE-ZIMPOL polarimetric maps obtained in the visible (645- 820 nm) of 14 out of the 17 ATOMIUM sources. They were obtained contemporaneously with the ALMA high spatial resolution data. To help interpret the polarized signal, we produced synthetic maps of light scattering by dust, through 3D radiative transfer simulations with the RADMC3D code. Results. The degree of linear polarization (DoLP) observed by ZIMPOL spreads across several optical filters. We infer that it primarily probes dust located just outside of the point spread function of the central source, and in or near the plane of the sky. The polarized signal is mainly produced by structures with a total optical depth close to unity in the line of sight, and it represents only a fraction of the total circumstellar dust. The maximum DoLP ranges from 0.03- 0.38 depending on the source, fractions that can be reproduced by our 3D pilot models for grains composed of olivine, melilite, corundum, enstatite, or forsterite. The spatial structure of the DoLP shows a diverse set of shapes, including clumps, arcs, and full envelopes. Only for three sources do we note a correlation between the ALMA CO ν = 0, J = 2-1 and SiO ν = 0, J = 5-4 lines, which trace the gas density, and the DoLP, which traces the dust. Conclusions. The clumpiness of the DoLP and the lack of a consistent correlation between the gas and the dust location show that, in the inner environment, dust formation occurs at very specific sites. This has potential consequences for the derived mass-loss rates and dust-to-gas ratio in the inner region of the circumstellar environment. Except for π1 Gru and perhaps GY Aql, we do not detect interactions between the circumstellar wind and the hypothesized companions that shape the wind at larger scales. This suggests that the orbits of any other companions are tilted out of the plane of the sky.
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| 6. |
- Wallström, Sofia, 1988, et al.
(författare)
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ATOMIUM: Molecular inventory of 17 oxygen-rich evolved stars observed with ALMA
- 2024
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 681
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Tidskriftsartikel (refereegranskat)abstract
- Context. The dusty winds of cool evolved stars are a major contributor of the newly synthesised material enriching the Galaxy and future generations of stars. However, the details of the physics and chemistry behind dust formation and wind launching have yet to be pinpointed. Recent spatially resolved observations show the importance of gaining a more comprehensive view of the circumstellar chemistry, but a comparative study of the intricate interplay between chemistry and physics is still difficult because observational details such as frequencies and angular resolutions are rarely comparable. Aims. Aiming to overcome these deficiencies, ATOMIUM is an ALMA Large Programme to study the physics and chemistry of the circumstellar envelopes of a diverse set of oxygen-rich evolved stars under homogeneous observing conditions at three angular resolutions between ∼0.02′1.4′. Here we summarize the molecular inventory of these sources, and the correlations between stellar parameters and molecular content. Methods. Seventeen oxygen-rich or S-Type asymptotic giant branch (AGB) and red supergiant (RSG) stars have been observed in several tunings with ALMA Band 6, targeting a range of molecules to probe the circumstellar envelope and especially the chemistry of dust formation close to the star. We systematically assigned the molecular carriers of the spectral lines and measured their spectroscopic parameters and the angular extent of the emission of each line from integrated intensity maps. Results. Across the ATOMIUM sample, we detect 291 transitions of 24 different molecules and their isotopologues. This includes several first detections in oxygen-rich AGB/RSG stars: PO v = 1, SO2 v1 = 1 and v2 = 2, and several high energy H2O transitions. We also find several first detections in S-Type AGB stars: vibrationally excited HCN v2 = 2,3 and SiS v = 4,5,6, as well as first detections of the molecules SiC, AlCl, and AlF in W Aql. Overall, we find strong correlations between the following molecular pairs: CS and SiS, CS and AlF, NaCl and KCl, AlO and SO, SO2 and SO, and SO2 and H2O; meaning both molecules tend to have more detected emission lines in the same sources. The measured isotopic ratios of Si and S are found to be consistent with previous measurements, except for an anomalously high 29Si/30Si ratio of 4 ± 1 in the RSG VX Sgr. Conclusions. This paper presents the overall molecular inventory and an initial analysis of the large ATOMIUM dataset, laying the groundwork for future work deriving molecular abundances and abundance profiles using radiative transfer modeling which will provide more rigorous tests for chemical models.
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| 7. |
- Danilovich, Taissa, 1987, et al.
(författare)
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Chemical tracers of a highly eccentric AGB–main-sequence star binary
- 2024
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Ingår i: Nature Astronomy. - 2397-3366.
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Tidskriftsartikel (refereegranskat)abstract
- Binary interactions have been proposed to explain a variety of circumstellar structures seen around evolved stars, including asymptotic giant branch (AGB) stars and planetary nebulae. Studies resolving the circumstellar envelopes of AGB stars have revealed spirals, disks and bipolar outflows, with shaping attributed to interactions with a companion. Here we use a combined chemical and dynamical analysis to reveal a highly eccentric and long-period orbit for W Aquilae, a binary system containing an AGB star and a main-sequence companion. Our results are based on anisotropic SiN emission, the detections of irregular NS and SiC emission towards the S-type star, and density structures observed in the CO emission. These features are all interpreted as having formed during periastron interactions. Our astrochemistry-based method can yield stringent constraints on the orbital parameters of long-period binaries containing AGB stars, and will be applicable to other systems.
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| 8. |
- Decin, L., et al.
(författare)
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(Sub)stellar companions shape the winds of evolved stars
- 2020
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 369:6509, s. 1497-1500
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Tidskriftsartikel (refereegranskat)abstract
- Binary interactions dominate the evolution of massive stars, but their role is less clear for low- and intermediate-mass stars. The evolution of a spherical wind from an asymptotic giant branch (AGB) star into a nonspherical planetary nebula (PN) could be due to binary interactions. We observed a sample of AGB stars with the Atacama Large Millimeter/submillimeter Array (ALMA) and found that their winds exhibit distinct nonspherical geometries with morphological similarities to planetary nebulae (PNe). We infer that the same physics shapes both AGB winds and PNe; additionally, the morphology and AGB mass-loss rate are correlated. These characteristics can be explained by binary interaction. We propose an evolutionary scenario for AGB morphologies that is consistent with observed phenomena in AGB stars and PNe.
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| 9. |
- Deuling, J H H, et al.
(författare)
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Closure of the femoral artery after cardiac catheterization : a comparison of Angio-Seal, StarClose, and manual compression.
- 2008
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Ingår i: Catheterization and cardiovascular interventions. - : Wiley. - 1522-1946 .- 1522-726X. ; 71:4, s. 518-23
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: To compare Angio-Seal (AS) and StarClose (SC) and manual compression (MC) on efficacy of hemostasis, complication rate, safety of early mobilization, and patient comfort. BACKGROUND: Closure of the femoral artery after cardiac catheterization can be obtained through different methods. Today, physicians can choose from a number of different devices to achieve arterial closure. METHODS: In a prospective trial 450 patients were randomized to AS, SC, or MC. Patients were mobilized 1 to 2 hr after device placement, and 6 hr after MC. Data were collected during hospital admission and by telephone at one month after hospital discharge. RESULTS: Devices were used in 138/150 allocated to AS and 124/150 allocated to SC patients (92% vs. 83%, P = 0.015) Patients with MC experienced more pain during sheath removal than patients receiving a device, and rated their period of bed rest as less comfortable. Oozing and need for pressure bandage at the puncture site were observed in 37 AS patients and 57 SC patients (25% vs. 38%, P = 0.002). Hematoma occurred in 15 AS patients, in 17 SC patients, and in 14 MC patients (11 vs. 14 vs. 9%, ns). CONCLUSION: There is no difference in safety between the three methods of arterial closure. SC was more often not used or successfully deployed. SC patients more often had continuing oozing. On patient comfort, closure devices performed better than MC. Early ambulation in patients with a closure device is safe. AS is the preferred method of arterial closure after cardiac catheterization.
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| 10. |
- Gottlieb, C. A., et al.
(författare)
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ATOMIUM: ALMA tracing the origins of molecules in dust forming oxygen rich M-type stars: Motivation, sample, calibration, and initial results
- 2022
-
Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 660
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Tidskriftsartikel (refereegranskat)abstract
- This overview paper presents atomium, a Large Programme in Cycle 6 with the Atacama Large Millimeter/submillimeter Array (ALMA). The goal of atomium is to understand the dynamics and the gas phase and dust formation chemistry in the winds of evolved asymptotic giant branch (AGB) and red supergiant (RSG) stars. A more general aim is to identify chemical processes applicable to other astrophysical environments. Seventeen oxygen-rich AGB and RSG stars spanning a range in (circum)stellar parameters and evolutionary phases were observed in a homogeneous observing strategy allowing for an unambiguous comparison. Data were obtained between 213.83 and 269.71 GHz at high (0.025-0.050), medium (0.13-0.24), and low (~1) angular resolution. The sensitivity per ~1.3 km s-1 channel was 1.5-5 mJy beam-1, and the line-free channels were used to image the millimetre wave continuum. Our primary molecules for studying the gas dynamics and dust formation are CO, SiO, AlO, AlOH, TiO, TiO2, and HCN; secondary molecules include SO, SO2, SiS, CS, H2O, and NaCl. The scientific motivation, survey design, sample properties, data reduction, and an overview of the data products are described. In addition, we highlight one scientific result - the wind kinematics of the atomium sources. Our analysis suggests that the atomium sources often have a slow wind acceleration, and a fraction of the gas reaches a velocity which can be up to a factor of two times larger than previously reported terminal velocities assuming isotropic expansion. Moreover, the wind kinematic profiles establish that the radial velocity described by the momentum equation for a spherical wind structure cannot capture the complexity of the velocity field. In fifteen sources, some molecular transitions other than 12CO v = 0 J = 2 - 1 reach a higher outflow velocity, with a spatial emission zone that is often greater than 30 stellar radii, but much less than the extent of CO. We propose that a binary interaction with a (sub)stellar companion may (partly) explain the non-monotonic behaviour of the projected velocity field. The atomium data hence provide a crucial benchmark for the wind dynamics of evolved stars in single and binary star models.
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| 11. |
- Ringh, M, et al.
(författare)
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The challenges and possibilities of public access defibrillation.
- 2018
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Ingår i: Journal of Internal Medicine. - : Wiley. - 0954-6820 .- 1365-2796. ; 283:3, s. 238-256
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Tidskriftsartikel (refereegranskat)abstract
- Out-of-hospital cardiac arrest (OHCA) is a major health problem that affects approximately four hundred and thousand patients annually in the United States alone. It is a major challenge for the emergency medical system as decreased survival rates are directly proportional to the time delay from collapse to defibrillation. Historically, defibrillation has only been performed by physicians and in-hospital. With the development of automated external defibrillators (AEDs), rapid defibrillation by nonmedical professionals and subsequently by trained or untrained lay bystanders has become possible. Much hope has been put to the concept of Public Access Defibrillation with a massive dissemination of public available AEDs throughout most Western countries. Accordingly, current guidelines recommend that AEDs should be deployed in places with a high likelihood of OHCA. Despite these efforts, AED use is in most settings anecdotal with little effect on overall OHCA survival. The major reasons for low use of public AEDs are that most OHCAs take place outside high incidence sites of cardiac arrest and that most OHCAs take place in residential settings, currently defined as not suitable for Public Access Defibrillation. However, the use of new technology for identification and recruitment of lay bystanders and nearby AEDs to the scene of the cardiac arrest as well as new methods for strategic AED placement redefines and challenges the current concept and definitions of Public Access Defibrillation. Existing evidence of Public Access Defibrillation and knowledge gaps and future directions to improve outcomes for OHCA are discussed. In addition, a new definition of the different levels of Public Access Defibrillation is offered as well as new strategies for increasing AED use in the society.
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| 12. |
- Vermeulen, R P, et al.
(författare)
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Prehospital diagnosis in STEMI patients treated by primary PCI : the key to rapid reperfusion.
- 2008
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Ingår i: Netherlands heart journal : monthly journal of the Netherlands Society of Cardiology and the Netherlands Heart Foundation. - 1568-5888. ; 16:1, s. 5-9
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Primary coronary intervention (PCI) for acute myocardial infarction should be performed as quickly as possible, with a door-toballoon time of less then 90 minutes. However, in daily practice this cannot always be achieved. Prehospital diagnosis of ST-elevation myocardial infarction (STEMI) is of major importance in reducing time to treatment, in particular when patients can be transported directly to a centre with interventional capacities. OBJECTIVES: The aim of the current study was to evaluate the time from prehospital diagnosis of STEMI to balloon inflation and identify factors related to treatment delay in patients directly referred to the catheterisation laboratory of the University Medical Centre of Groningen. METHODS: A cross-sectional descriptive design was used to collect data on patients treated with primary PCI after prehospital diagnosis of STEMI. RESULTS: Median prehospital diagnosis-to-balloon time was 64 minutes for patients directly admitted to the catheterisation laboratory and 75 minutes for patients initially admitted to the coronary care unit. A delay longer than 90 minutes was observed in 18 patients. Higher age was associated with longer delay times (p=0.041). Long delays were not associated with diabetes (p=0.293), time from symptom onset to prehospital diagnosis (p=0.87) or time of day (p=0.09). Initial unavailability of the catheterisation laboratory due to running procedures contributed to longer delay times in ten cases. CONCLUSION: Prehospital diagnosis of STEMI and direct referral to a catheterisation laboratory for primary PCI allows a prehospital diagnosis-toballoon time of less than 90 minutes in 82% of patients. Older patients are at risk of longer delays. (Neth Heart J 2008;16:5-9.).
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| 13. |
- Andriantsaralaza, Miora, et al.
(författare)
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DEATHSTAR: Nearby AGB stars with the Atacama Compact Array: II. CO envelope sizes and asymmetries: The S-type stars
- 2021
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 653
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Tidskriftsartikel (refereegranskat)abstract
- Aims. We aim to constrain the sizes of, and investigate deviations from spherical symmetry in, the CO circumstellar envelopes (CSEs) of 16 S-type stars, along with an additional 7 and 4 CSEs of C-type and M-type AGB stars, respectively. Methods. We map the emission from the CO J = 2-1 and 3-2 lines observed with the Atacama Compact Array (ACA) and its total power (TP) antennas, and fit with a Gaussian distribution in the uv- and image planes for ACA-only and TP observations, respectively. The major axis of the fitted Gaussian for the CO(2-1) line data gives a first estimate of the size of the CO-line-emitting CSE. We investigate possible signs of deviation from spherical symmetry by analysing the line profiles and the minor-to-major axis ratio obtained from visibility fitting, and by investigating the deconvolved images. Results. The sizes of the CO-line-emitting CSEs of low-mass-loss-rate (low-MLR) S-type stars fall between the sizes of the CSEs of C-stars, which are larger, and those of M-stars, which are smaller, as expected because of the differences in their respective CO abundances and the dependence of the photodissociation rate on this quantity. The sizes of the low-MLR S-type stars show no dependence on circumstellar density, as measured by the ratio of the MLR to terminal outflow velocity, irrespective of variability type. The density dependence steepens for S-stars with higher MLRs. While the CO(2-1) brightness distribution size of the low-density S-stars is in general smaller than the predicted photodissociation radius (assuming the standard interstellar radiation field), the measured size of a few of the high-density sources is of the same order as the expected photodissociation radius. Furthermore, our results show that the CO CSEs of most of the S-stars in our sample are consistent with a spherically symmetric and smooth outflow. For some of the sources, clear and prominent asymmetric features are observed which are indicative of intrinsic circumstellar anisotropy. Conclusions. As the majority of the S-type CSEs of the stars in our sample are consistent with a spherical geometry, the CO envelope sizes obtained in this paper will be used to constrain detailed radiative transfer modelling to directly determine more accurate MLR estimates for the stars in our sample. For several of our sources that present signs of deviation from spherical symmetry, further high-resolution observations would be necessary to investigate the nature of, and the physical processes behind, these asymmetrical structures. This will provide further insight into the mass-loss process and its related chemistry in S-type AGB stars.
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| 14. |
- De Marco, O., et al.
(författare)
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The messy death of a multiple star system and the resulting planetary nebula as observed by JWST
- 2022
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Ingår i: Nature Astronomy. - : Springer Science and Business Media LLC. - 2397-3366. ; 6:12, s. 1421-1432
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Tidskriftsartikel (refereegranskat)abstract
- Planetary nebulae—the ejected envelopes of red giant stars—provide us with a history of the last, mass-losing phases of 90% of stars initially more massive than the Sun. Here we analyse images of the planetary nebula NGC 3132 from the James Webb Space Telescope (JWST) Early Release Observations. A structured, extended hydrogen halo surrounding an ionized central bubble is imprinted with spiral structures, probably shaped by a low-mass companion orbiting the central star at about 40–60 au. The images also reveal a mid-infrared excess at the central star, interpreted as a dusty disk, which is indicative of an interaction with another closer companion. Including the previously known A-type visual companion, the progenitor of the NGC 3132 planetary nebula must have been at least a stellar quartet. The JWST images allow us to generate a model of the illumination, ionization and hydrodynamics of the molecular halo, demonstrating the power of JWST to investigate complex stellar outflows. Furthermore, new measurements of the A-type visual companion allow us to derive the value for the mass of the progenitor of a central star with excellent precision: 2.86 ± 0.06 M⊙. These results serve as pathfinders for future JWST observations of planetary nebulae, providing unique insight into fundamental astrophysical processes including colliding winds and binary star interactions, with implications for supernovae and gravitational-wave systems.
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| 15. |
- Decin, L., et al.
(författare)
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Reduction of the maximum mass-loss rate of OH/IR stars due to unnoticed binary interaction
- 2019
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Ingår i: Nature Astronomy. - : Springer Science and Business Media LLC. - 2397-3366. ; 3:5, s. 408-415
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- © 2019, The Author(s), under exclusive licence to Springer Nature Limited. In 1981, the idea of a superwind that ends the life of cool giant stars was proposed 1 . Extreme oxygen-rich giants, OH/IR stars, develop superwinds with the highest mass-loss rates known so far, up to a few 10 −4 solar masses (M ⊙ ) per year 2–12 , informing our understanding of the maximum mass-loss rate achieved during the asymptotic giant branch (AGB) phase. A conundrum arises whereby the observationally determined duration of the superwind phase is too short for these stars to lose enough mass to become white dwarfs 2–4,6,8–10 . Here we report on the detection of spiral structures around two cornerstone extreme OH/IR stars, OH 26.5 + 0.6 and OH 30.1 − 0.7, thereby identifying them as wide binary systems. Hydrodynamic simulations show that the companion’s gravitational attraction creates an equatorial density enhancement mimicking a short, extreme superwind phase, thereby solving the decades-old conundrum. This discovery restricts the maximum mass-loss rate of AGB stars to around the single-scattering radiation pressure limit of a few 10 −5 M ⊙ yr −1 . This has crucial implications for nucleosynthetic yields, planet survival and the wind-driving mechanism.
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| 16. |
- Dieperink, W, et al.
(författare)
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Treatment of presumed acute cardiogenic pulmonary oedema in an ambulance system by nurses using Boussignac continuous positive airway pressure.
- 2009
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Ingår i: Emergency Medicine Journal. - : BMJ. - 1472-0205 .- 1472-0213. ; 26:2, s. 141-4
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Early initiation of continuous positive airway pressure (CPAP) applied by face mask benefits patients with acute cardiogenic pulmonary oedema (ACPE). The simple disposable Boussignac CPAP (BCPAP) has been used in ambulances by physicians. In the Netherlands, ambulances are manned by nurses and not physicians. It was hypothesised that ambulance nurses are able to identify patients with ACPE and can successfully apply BCPAP. A prospective case series of patients with presumed ACPE treated with BCPAP by ambulance nurses is described. METHODS: After training of ambulance nurses, all 33 ambulances in the region were equipped with BCPAP. ACPE was diagnosed on clinical signs and pulse oximetry saturation (Spo(2)) <95%. BCPAP (5 cm H(2)O, Fio(2)>80%) was generated with an oxygen flow of 15 l/min. The physiological responses, experiences and clinical outcomes of the patients were collected from ambulance and hospital records, and ambulance nurses and patients received a questionnaire. RESULTS: From March to December 2006, 32 patients (age range 61-94 years) received BCPAP during transport to six different regional hospitals. In 26 patients (81%) a diagnosis of ACPE was confirmed. With BCPAP, median (IQR) Spo(2) increased from 79% (69-94%) to 96% (89-98%) within 20 min. The median (IQR) duration of BCPAP treatment was 26 min (21-32). The patients had no negative recollections of the treatment. Ambulance personnel were satisfied with the BCPAP therapy. CONCLUSION: When applied by ambulance nurses, BCPAP was feasible and effective in improving oxygen saturation in patients with ACPE. Although survival benefit can only be demonstrated by further research, it is considered that BCPAP can be implemented in all ambulances in the Netherlands.
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| 17. |
- Groenewegen, M. A. T., et al.
(författare)
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The ALMA detection of CO rotational line emission in AGB stars in the Large Magellanic Cloud
- 2016
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 596, s. 50-
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Tidskriftsartikel (refereegranskat)abstract
- Context. Low- and intermediate-mass stars lose most of their stellar mass at the end of their lives on the asymptotic giant branch (AGB). Determining gas and dust mass-loss rates (MLRs) is important in quantifying the contribution of evolved stars to the enrichment of the interstellar medium.Aims. This study attempts to spectrally resolve CO thermal line emission in a small sample of AGB stars in the Large Magellanic Cloud (LMC).Methods. The Atacama Large Millimeter Array was used to observe two OH/IR stars and four carbon stars in the LMC in the CO J = 2−1 line.Results. We present the first measurement of expansion velocities in extragalactic carbon stars. All four C stars are detected and wind expansion velocities and stellar velocities are directly measured. Mass-loss rates are derived from modelling the spectral energy distribution and Spitzer/IRS spectrum with the DUSTY code. The derived gas-to-dust ratios allow the predicted velocities to agree with the observed gas-to-dust ratios. The expansion velocities and MLRs are compared to a Galactic sample of well-studied relatively low MLRs stars supplemented with extreme C stars with properties that are more similar to the LMC targets. Gas MLRs derived from a simple formula are significantly smaller than those derived from dust modelling, indicating an order of magnitude underestimate of the estimated CO abundance, time-variable mass loss, or that the CO intensities in LMC stars are lower than predicted by the formula derived for Galactic objects. This could be related to a stronger interstellar radiation field in the LMC.Conclusions. Although the LMC sample is small and the comparison to Galactic stars is non-trivial because of uncertainties in their distances (hence luminosities), it appears that for C stars the wind expansion velocities in the LMC are lower than in the solar neighbourhood, while the MLRs appear to be similar. This is in agreement with dynamical dust-driven wind models.
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| 18. |
- In ’t Veld, Sjors G.J.G., et al.
(författare)
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Detection and localization of early- and late-stage cancers using platelet RNA
- 2022
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Ingår i: Cancer Cell. - : Elsevier. - 1535-6108 .- 1878-3686. ; 40:9, s. 999-1009.e6
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Tidskriftsartikel (refereegranskat)abstract
- Cancer patients benefit from early tumor detection since treatment outcomes are more favorable for less advanced cancers. Platelets are involved in cancer progression and are considered a promising biosource for cancer detection, as they alter their RNA content upon local and systemic cues. We show that tumor-educated platelet (TEP) RNA-based blood tests enable the detection of 18 cancer types. With 99% specificity in asymptomatic controls, thromboSeq correctly detected the presence of cancer in two-thirds of 1,096 blood samples from stage I–IV cancer patients and in half of 352 stage I–III tumors. Symptomatic controls, including inflammatory and cardiovascular diseases, and benign tumors had increased false-positive test results with an average specificity of 78%. Moreover, thromboSeq determined the tumor site of origin in five different tumor types correctly in over 80% of the cancer patients. These results highlight the potential properties of TEP-derived RNA panels to supplement current approaches for blood-based cancer screening.
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| 19. |
- Kedhi, E., et al.
(författare)
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A prospective, randomized, open-label trial of 6-month versus 12-month dual antiplatelet therapy after drug-eluting stent implantation in ST-elevation myocardial infarction: Rationale and design of the "DAPT-STEMI trial"
- 2017
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Ingår i: American Heart Journal. - : Elsevier BV. - 0002-8703. ; 188, s. 11-17
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Tidskriftsartikel (refereegranskat)abstract
- Background The optimal duration of dual antiplatelet therapy (DAPT) after percutaneous coronary intervention with second-generation drug eluting stents (DESs) is unclear. Because prolonged DAPT is associated with higher bleeding risk and health care costs, establishing optimal DAPT duration is of paramount importance. No other randomized controlled trials have evaluated the safety of shorter DAPT duration in ST-elevation myocardial infarction (STEMI) patients treated with second generation DESs and latest P2Y12 platelet receptor inhibitors. Hypothesis Six months of DAPT after Resolute Integrity stent implantation in STEMI patients is not inferior to 12 months of DAPT in clinical outcomes. Study design The Dual Antiplatelet Therapy After Drug-Eluting Stent Implantation In ST-elevation Myocardial Infarction (DAPT-STEMI) trial is a randomized, multicenter, international, open-label trial designed to examine the safety (noninferiority) of 6-month DAPT after Resolute Integrity stent implantation in STEMI patients compared with 12-month DAPT. Event-free patients on DAPT at 6month will be randomized (1:1 fashion) between single (aspirin only) versus DAPT for an additional 6 months and followed until 2 years after primary percutaneous coronary intervention. The primary end point is a patient-oriented composite endpoint of all-cause mortality, any myocardial infarction, any revascularization, stroke, and major bleeding (net adverse clinical events [NACE]) at 18 months after randomization. To achieve a power of 85% for a noninferiority limit of 1.66, a total of 1100 enrolled patients are required. Summary The DAPT-STEMI trial aims to assess in STEMI patients treated with second-generation DESs whether discontinuation of DAPT after 6 months of event-free survival is noninferior to routine 12-month DAPT.
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| 20. |
- Kedhi, E., et al.
(författare)
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Six months versus 12 months dual antiplatelet therapy after drug-eluting stent implantation in ST-elevation myocardial infarction (DAPT-STEMI): randomised, multicentre, non-inferiority trial
- 2018
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Ingår i: Bmj-British Medical Journal. - : BMJ. - 1756-1833. ; 363
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE To show that limiting dual antiplatelet therapy (DAPT) to six months in patients with event-free ST-elevation myocardial infarction (STEMI) results in a non-inferior clinical outcome versus DAPT for 12 months. Patients with STEMI treated with primary percutaneous coronary intervention (PCI) and second generation zotarolimus-eluting stent. Patients with STEMI aged 18 to 85 that underwent a primary PCI with the implantation of second generation drug-eluting stents were enrolled in the trial. Patients that were event-free at six months after primary PCI were randomised at this time point. Patients that were taking DAPT and were event-free at six months were randomised 1:1 to single antiplatelet therapy (SAPT) (ie, aspirin only) or to DAPT for an additional six months. All patients that were randomised were then followed for another 18 months (ie, 24 months after the primary PCI). The primary endpoint was a composite of all cause mortality, any myocardial infarction, any revascularisation, stroke, and thrombolysis in myocardial infarction major bleeding at 18 months after randomisation. A total of 1100 patients were enrolled in the trial between 19 December 2011 and 30 June 2015. 870 were randomised: 432 to SAPT versus 438 to DAPT. The primary endpoint occurred in 4.8% of patients receiving SAPT versus 6.6% of patients receiving DAPT (hazard ratio 0.73, 95% confidence interval 0.41 to 1.27, P=0.26). Non-inferiority was met (P=0.004 for non-inferiority), as the upper 95% confidence interval of 1.27 was smaller than the prespecified non-inferiority margin of 1.66. DAPT to six months was non-inferior to DAPT for 12 months in patients with event-free STEMI at six months after primary PCI with second generation drug-eluting stents.
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| 21. |
- Koumpia, E., et al.
(författare)
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Optical and near-infrared observations of the Fried Egg Nebula: Multiple shell ejections on a 100 yr timescale from a massive yellow hypergiant
- 2020
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 635
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Tidskriftsartikel (refereegranskat)abstract
- Context. The fate of a massive star during the latest stages of its evolution is highly dependent on its mass-loss rate and geometry and therefore knowing the geometry of the circumstellar material close to the star and its surroundings is crucial. Aims. We aim to provide insight into the nature (i.e. geometry, rates) of mass-loss episodes, and in particular, the connection between the observed asymmetries due to the mass lost in a fast wind or during a previous, prodigious mass-losing phase. In this context, yellow hypergiants offer a good opportunity to study mass-loss events. Methods. We analysed a large set of optical and near-infrared data in spectroscopic and photometric, spectropolarimetric, and interferometric (GRAVITY/VLTI) modes, towards the yellow hypergiant IRAS 17163-3907. We used X-shooter optical observations to determine the spectral type of this yellow hypergiant and we present the first model-independent, reconstructed images of IRAS 17163-3907 at these wavelengths tracing milli-Arcsecond scales. Lastly, we applied a 2D radiative transfer model to fit the dereddened photometry and the radial profiles of published diffraction-limited VISIR images at 8.59 μm, 11.85 μm, and 12.81 μm simultaneously, adopting a revised distance determination using Gaia Data Release 2 measurements. Results. We constrain the spectral type of IRAS 17163-3907 to be slightly earlier than A6Ia (Teffâ ∼â 8500 K). The interferometric observables around the 2 μm window towards IRAS 17163-3907 show that the Brγ emission appears to be more extended and asymmetric than the Naâ » I and the continuum emission. Interestingly, the spectrum of IRAS 17163-3907 around 2 μm shows Mgâ » II emission that is not previously seen in other objects of its class. In addition, Brγ shows variability in a time interval of four months that is not seen towards Naâ » I. Lastly, in addition to the two known shells surrounding IRAS 17163-3907, we report on the existence of a third hot inner shell with a maximum dynamical age of only 30 yr. Conclusions. The 2 μm continuum originates directly from the star and not from hot dust surrounding the stellar object. The observed spectroscopic variability of Brγ could be a result of variability in the mass-loss rate. The interpretation of the presence of Naâ » I emission at closer distances to the star compared to Brγ has been a challenge in various studies. To address this, we examine several scenarios. We argue that the presence of a pseudo-photosphere, which was traditionally considered to be the prominent explanation, is not needed and that it is rather an optical depth effect. The three observed distinct mass-loss episodes are characterised by different mass-loss rates and can inform theories of mass-loss mechanisms, which is a topic still under debate both in theory and observations. We discuss these in the context of photospheric pulsations and wind bi-stability mechanisms.
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| 22. |
- Lykou, F., et al.
(författare)
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Dissecting the AGB star L-2 Puppis : a torus in the making
- 2015
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 576
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Tidskriftsartikel (refereegranskat)abstract
- Aims. The circumstellar environment of L-2 Pup, an oxygen-rich semiregular variable, was observed to understand the evolution of mass loss and the shaping of ejecta in the late stages of stellar evolution. Methods. High-angular resolution observations from a single 8 m telescope were obtained using aperture masking in the near-infrared (1.64, 2.30 and 3.74 mu m) on the NACO/VLT, both in imaging and polarimetric modes. Results. The aperture-masking images of L-2 Pup at 2.30 mu m show a resolved structure that resembles a toroidal structure with a major axis of similar to 140 milliarcseconds (mas) and an east-west orientation. Two clumps can be seen on either side of the star, similar to 65 mas from the star, beyond the edge of the circumstellar envelope (estimated diameter is similar to 27 mas), while a faint, hook-like structure appear toward the northeast. The patterns are visible both in the imaging and polarimetric mode, although the latter was only used to measure the total intensity (Stokes I). The overall shape of the structure is similar at the 3.74 mu m pseudo-continuum (dust emission), where the clumps appear to be embedded within a dark, dusty lane. The faint, hook-like patterns are also seen at this wavelength, extending northeast and southwest with the central, dark lane being an apparent axis of symmetry. We interpret the structure as a circumstellar torus with inner radius of 4.2 au. With a rotation velocity of 10 kms(-1) as suggested by the SiO maser profile, we estimate a stellar mass of 0.7 M-circle dot.
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| 23. |
- Lykou, F., et al.
(författare)
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Unraveling Disks in AGB Stars
- 2015
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Ingår i: EAS Publications Series. - : EDP Sciences. - 1633-4760 .- 1638-1963. - 9782759819072 ; 71-72, s. 217-222
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Konferensbidrag (refereegranskat)abstract
- It is commonly accepted that asymmetries found in the post-AGB stars and planetary nebulae should originate as early as during the AGB phase. We present results from our high-angular resolution observing programs, with an aperture masking technique on the VLT, of a sample of evolved stars that were known to present asymmetries at larger spatial scales (e.g. jets, torii and/or bipolar nebulae). Disk-like structures have been found in the vicinity of at least two of these stars.
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| 24. |
- Postma, W., et al.
(författare)
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Resolute zotarolimus-eluting stent in ST-elevation myocardial infarction (resolute-STEMI): A prespecified prospective register from the DAPT-STEMI trial
- 2020
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Ingår i: Catheterization and Cardiovascular Interventions. - : Wiley. - 1522-1946 .- 1522-726X. ; 95:4, s. 706-710
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Tidskriftsartikel (refereegranskat)abstract
- Objectives To evaluate the safety and efficacy outcomes after primary percutaneous coronary intervention (pPCI) with second-generation Resolute (TM) zotarolimus-eluting stent (R-ZES) in patients enrolled in the DAPT-STEMI Trial (NCT01459627). Background R-ZES is one of the most used drug eluting stents worldwide. To date, the safety and efficacy data of this stent in setting of STEMI is limited. Methods The Resolute-STEMI is a prespecified prospective register that reports the safety and efficacy of R-ZES in setting of ST-Elevation Myocardial Infarction (STEMI) at 6 months for the following endpoints: a composite endpoint of all-cause mortality, any myocardial infarction (MI), any (unscheduled) revascularization, stroke and TIMI major bleeding, as well as target lesion failure and stent thrombosis (ST). Results From a total of 1,100 STEMI patients enrolled in the trial, 998 received a R-ZES. At 6 months the PE occurred in 42 (4.2%) patients. All-cause death, MI, revascularization, stroke and TIMI major bleeding was respectively 8 (0.8%), 9 (0.8%), 34 (3.4%), 2 (0.2%), and 4 (0.4%). The rate of target lesion revascularizations involving the culprit lesion was 1.1%. Target lesion failure was 1.5%. The rate of definite ST was 0.5%. The rate of both definite or probable ST was 0.7%. Conclusions The present analysis is the largest to date reporting short-term and mid-term clinical outcomes with the R-ZES stent in setting of STEMI. At 30 days and 6-months R-ZES has an outstanding safety and efficacy even in this high-risk category of patients.
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| 25. |
- Ramstedt, Sofia, et al.
(författare)
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DEATHSTAR: Nearby AGB stars with the Atacama Compact Array I. CO envelope sizes and asymmetries: A new hope for accurate mass-loss-rate estimates
- 2020
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 640
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Tidskriftsartikel (refereegranskat)abstract
- Context. This is the first publication from the DEATHSTAR project. The overall goal of the project is to reduce the uncertainties of the observational estimates of mass-loss rates from evolved stars on the Asymptotic Giant Branch (AGB). Aim. The aim in this first publication is to constrain the sizes of the (CO)-C-12 emitting region from the circumstellar envelopes around 42 mostly southern AGB stars, of which 21 are M-type and 21 are C-type, using the Atacama Compact Array (ACA) at the Atacama Large Millimeter/submillimeter Array. The symmetry of the outflows is also investigated. Methods. Line emission from (CO)-C-12 J = 2 -> 1 and 3 -> 2 from all of the sources were mapped using the ACA. In this initial analysis, the emission distribution was fit to a Gaussian distribution in the uv-plane. A detailed radiative transfer analysis will be presented in a future publication. The major and minor axis of the best-fit Gaussian at the line center velocity of the (CO)-C-12 J = 2 -> 1 emission gives a first indication of the size of the emitting region. Furthermore, the fitting results, such as the Gaussian major and minor axis, center position, and the goodness of fit across both lines, constrain the symmetry of the emission distribution. For a subsample of sources, the measured emission distribution is compared to predictions from previous best-fit radiative transfer modeling results. Results. We find that the CO envelope sizes are, in general, larger for C-type than for M-type AGB stars, which is as expected if the CO/H-2 ratio is larger in C-type stars. Furthermore, the measurements show a relation between the measured (Gaussian) (CO)-C-12 J = 2 -> 1 size and circumstellar density that, while in broad agreement with photodissociation calculations, reveals large scatter and some systematic differences between the different stellar types. For lower mass-loss-rate irregular and semi-regular variables of both M- and C-type AGB stars, the (CO)-C-12 J = 2 -> 1 size appears to be independent of the ratio of the mass-loss rate to outflow velocity, which is a measure of circumstellar density. For the higher mass-loss-rate Mira stars, the (CO)-C-12 J = 2 -> 1 size clearly increases with circumstellar density, with larger sizes for the higher CO-abundance C-type stars. The M-type stars appear to be consistently smaller than predicted from photodissociation theory. The majority of the sources have CO envelope sizes that are consistent with a spherically symmetric, smooth outflow, at least on larger scales. For about a third of the sources, indications of strong asymmetries are detected. This is consistent with what was found in previous interferometric investigations of northern sources. Smaller scale asymmetries are found in a larger fraction of sources. Conclusions. These results for CO envelope radii and shapes can be used to constrain detailed radiative transfer modeling of the same stars so as to determine mass-loss rates that are independent of photodissociation models. For a large fraction of the sources, observations at higher spatial resolution will be necessary to deduce the nature and origin of the complex circumstellar dynamics revealed by our ACA observations.
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| 26. |
- Richards, A. M. S., et al.
(författare)
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ALMA sub-mm maser and dust distribution of VY Canis Majoris
- 2014
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 572
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Tidskriftsartikel (refereegranskat)abstract
- Aims. Cool, evolved stars have copious, enriched winds. Observations have so far not fully constrained models for the shaping and acceleration of these winds. We need to understand the dynamics better, from the pulsating stellar surface to similar to 10 stellar radii, where radiation pressure on dust is fully effective. Asymmetric nebulae around some red supergiants imply the action of additional forces. Methods. We retrieved ALMA Science Verification data providing images of sub-mm line and continuum emission from VY CMa. This enables us to locate water masers with milli-arcsec accuracy and to resolve the dusty continuum. Results. The 658, 321, and 325 GHz masers lie in irregular, thick shells at increasing distances from the centre of expansion. For the first time this is confirmed as the stellar position, coinciding with a compact peak offset to the NW of the brightest continuum emission. The maser shells overlap but avoid each other on scales of up to 10 au. Their distribution is broadly consistent with excitation models but the conditions and kinematics are complicated by wind collisions, clumping, and asymmetries.
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| 27. |
- Rizvi, Saiyada N. F., et al.
(författare)
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Biodistribution, radiation dosimetry and scouting of 90Y-ibritumomab tiuxetan therapy in patients with relapsed B-cell non-Hodgkin's lymphoma using 89Zr-ibritumomab tiuxetan and PET
- 2012
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Ingår i: European Journal of Nuclear Medicine and Molecular Imaging. - : Springer Science and Business Media LLC. - 1619-7070 .- 1619-7089. ; 39:3, s. 512-520
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Positron emission tomography (PET) with Zr-89-britumomab tiuxetan can be used to monitor biodistribution of Y-90-ibritumomab tiuxetan as shown in mice. The aim of this study was to assess biodistribution and radiation dosimetry of 90Y-ibritumomab tiuxetan in humans on the basis of Zr-89-ibritumomab tiuxetan imaging, to evaluate whether co-injection of a therapeutic amount of Y-90-ibritumomab tiuxetan influences biodistribution of Zr-89-ibritumomabtiuxetan and whether pre-therapy scout scans with Zr-89-ibritumomab tiuxetan can be used to predict biodistribution of Y-90-ibritumomab tiuxetan and the dose-limiting organ during therapy. Methods: Seven patients with relapsed B-cell non-Hodgkin's lymphoma scheduled for autologous stem cell transplantation underwent PET scans at 1, 72 and 144 h after injection of similar to 70 MBq Zr-89-ibritumomab tiuxetan and again 2 weeks later after co-injection of 15 MBq/kg or 30 MBq/kg Y-90-britumomab tiuxetan. Volumes of interest were drawn over liver, kidneys, lungs, spleen and tumours. Ibritumomab tiuxetan organ absorbed doses were calculated using OLINDA. Red marrow dosimetry was based on blood samples. Absorbed doses to tumours were calculated using exponential fits to the measured data. Results: The highest Y-90 absorbed dose was observed in liver (3.2 +/- 1.8 mGy/MBq) and spleen (2.9 +/- 0.7 mGy/MBq) followed by kidneys and lungs. The red marrow dose was 0.52 +/- 0.04 mGy/MBq, and the effective dose was 0.87 +/- 0.14 mSv/MBq. Tumour absorbed doses ranged from 8.6 to 28.6 mGy/MBq. Correlation between predicted pre-therapy and therapy organ absorbed doses as based on Zr-89-ibritumomab tiuxetan images was high (Pearson correlation coefficient r=0.97). No significant difference between pre-therapy and therapy tumour absorbed doses was found, but correlation was lower (r=0.75). Conclusion: Biodistribution of Zr-89-ibritumomab tiuxetan is not influenced by simultaneous therapy with Y-90-ibritumomab tiuxetan, and Zr-89-ibritumomab tiuxetan scout scans can thus be used to predict biodistribution and dose-limiting organ during therapy. Absorbed doses to spleen were lower than those previously estimated using In-111-ibritumomab tiuxetan. The dose-limiting organ in patients undergoing stem cell transplantation is the liver.
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| 28. |
- Sabin, L., et al.
(författare)
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ALMA reveals the coherence of the magnetic field geometry in OH 231.8+4.2
- 2020
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Ingår i: Monthly Notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 495:4, s. 4297-4305
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Tidskriftsartikel (refereegranskat)abstract
- In a continuing effort to investigate the role of magnetic fields in evolved low- and intermediate-mass stars (principally regarding the shaping of their envelopes), we present new Atacama Large Millimeter/submillimeter Array (ALMA) high-resolution polarization data obtained for the nebula OH 231.8+4.2. We found that the polarized emission likely arises from aligned grains in the presence of magnetic fields rather than radiative alignment and self-scattering. The ALMA data show well organized electric field orientations in most of the nebula and the inferred magnetic field vectors (rotated by 90 degrees) trace an hourglass morphology centred on the central system of the nebula. One region in the southern part of OH 231.8+4.2 shows a less organized distribution probably due to the shocked environment. These findings, in conjunction with earlier investigations (maser studies and dust emission analysis at other scales and wavelengths) suggest an overall magnetic hourglass located inside a toroidal field. We propose the idea that the magnetic field structure is closely related to the architecture of a magnetic tower and that the outflows were therefore magnetically launched. While the current dynamical effect of the fields might be weak in the equatorial plane principally due to the evolution of the envelope, it would still be affecting the outflows. In that regard, the measurement of the magnetic field at the stellar surface, which is still missing, combined with a full magnetohydrodynamic treatment are required to better understand and constrain the events occurring in OH 231.8+4.2.
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| 29. |
- Vermeulen, Robert P, et al.
(författare)
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Clinical correlates of arterial lactate levels in patients with ST-segment elevation myocardial infarction at admission : a descriptive study
- 2010
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Ingår i: Critical Care. - : Springer Science and Business Media LLC. - 1364-8535 .- 1466-609X. ; 14:5, s. R164-
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Tidskriftsartikel (refereegranskat)abstract
- ABSTRACT : INTRODUCTION : Blood lactate measurements can be used as an indicator of hemodynamic impairment and relate to mortality in various forms of shock. Little is known at the moment concerning the clinical correlates of systemic lactate in patients with ST-segment elevation myocardial infarction (STEMI). METHODS : To assess the relation of systemic arterial lactate levels in STEMI patients with clinical correlates at presentation in the catheterization laboratory, we measured arterial lactate levels with a rapid point-of-care technique, immediately following femoral sheath insertion. The study population (n= 1,176) was divided into tertiles with lactate levels ≤1.1 (n = 410), 1.2 to 1.7 (n = 398) and ≥1.8 mmol/l (n = 368). We compared both baseline characteristics and outcome measures of the three lactate groups. RESULTS : Factors independently associated with higher lactate levels were hypotension, heart rate, thrombolysis in myocardial infarction (TIMI) flow 0 to 1, diabetes and non-smoking. Mortality at 30 days in the three groups was 2.0%, 1.5% and 6.5%. The latter group also showed lower blush grades and greater enzymatic infarct sizes. An intra aortic balloon pump (IABP) was used more frequently in patients with higher lactate levels (4.2%, 7.6% and 14.7%). CONCLUSIONS : In STEMI patients, impaired hemodynamics, worse TIMI flow and non-smoking were related to increased arterial lactate levels. Higher lactate levels were independently related with 30-day mortality and an overall worse response to percutaneous coronary intervention (PCI). In particular, acute mortality was related to admission lactates ≥1.8 mmol/L. Point-of-care measurement of arterial lactate at admission in patients with STEMI has the potential to improve acute risk stratification.
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| 30. |
- Welsh, Joshua A., et al.
(författare)
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Minimal information for studies of extracellular vesicles (MISEV2023): From basic to advanced approaches
- 2024
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Ingår i: Journal of Extracellular Vesicles. - : John Wiley and Sons Inc. - 2001-3078. ; 13:2
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Tidskriftsartikel (refereegranskat)abstract
- Extracellular vesicles (EVs), through their complex cargo, can reflect the state of their cell of origin and change the functions and phenotypes of other cells. These features indicate strong biomarker and therapeutic potential and have generated broad interest, as evidenced by the steady year-on-year increase in the numbers of scientific publications about EVs. Important advances have been made in EV metrology and in understanding and applying EV biology. However, hurdles remain to realising the potential of EVs in domains ranging from basic biology to clinical applications due to challenges in EV nomenclature, separation from non-vesicular extracellular particles, characterisation and functional studies. To address the challenges and opportunities in this rapidly evolving field, the International Society for Extracellular Vesicles (ISEV) updates its ‘Minimal Information for Studies of Extracellular Vesicles’, which was first published in 2014 and then in 2018 as MISEV2014 and MISEV2018, respectively. The goal of the current document, MISEV2023, is to provide researchers with an updated snapshot of available approaches and their advantages and limitations for production, separation and characterisation of EVs from multiple sources, including cell culture, body fluids and solid tissues. In addition to presenting the latest state of the art in basic principles of EV research, this document also covers advanced techniques and approaches that are currently expanding the boundaries of the field. MISEV2023 also includes new sections on EV release and uptake and a brief discussion of in vivo approaches to study EVs. Compiling feedback from ISEV expert task forces and more than 1000 researchers, this document conveys the current state of EV research to facilitate robust scientific discoveries and move the field forward even more rapidly.
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| 31. |
- Wesson, R., et al.
(författare)
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JWST observations of the Ring Nebula (NGC 6720): I. Imaging of the rings, globules, and arcs
- 2024
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Ingår i: Monthly Notices of the Royal Astronomical Society. - 0035-8711 .- 1365-2966. ; 528:2, s. 3392-3416
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Tidskriftsartikel (refereegranskat)abstract
- We present JWST images of the well-known planetary nebula NGC 6720 (the Ring Nebula), covering wavelengths from 1.6 to 25 m. The bright shell is strongly fragmented with some 20 000 dense globules, bright in H2, with a characteristic diameter of 0.2 arcsec and density nH ∼105-106 cm-3. The shell contains a narrow ring of polycyclic aromatic hydrocarbon (PAH) emission. H2 is found throughout the shell and also in the halo. H2 in the halo may be located on the swept-up walls of a biconal polar flow. The central cavity is filled with high-ionization gas and shows two linear structures which we suggest are the edges of a biconal flow, seen in projection against the cavity. The central star is located 2 arcsec from the emission centroid of the cavity and shell. Linear features ('spikes') extend outward from the ring, pointing away from the central star. Hydrodynamical simulations reproduce the clumping and possibly the spikes. Around 10 low-contrast, regularly spaced concentric arc-like features are present; they suggest orbital modulation by a low-mass companion with a period of about 280 yr. A previously known much wider companion is located at a projected separation of about 15 000 au; we show that it is an M2-M4 dwarf. NGC 6720 is therefore a triple star system. These features, including the multiplicity, are similar to those seen in the Southern Ring Nebula (NGC 3132) and may be a common aspect of such nebulae.
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