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- Benmahi, B., et al.
(författare)
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Monitoring of the evolution of H2O vapor in the stratosphere of Jupiter over an 18-yr period with the Odin space telescope
- 2020
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 641
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Tidskriftsartikel (refereegranskat)abstract
- Context. The comet Shoemaker-Levy 9 impacted Jupiter in July 1994, leaving its stratosphere with several new species, with water vapor (H2O) among them. Aims. With the aid of a photochemical model, H2O can be used as a dynamical tracer in the Jovian stratosphere. In this paper, we aim to constrain the vertical eddy diffusion (Kzz) at levels where H2O is present. Methods. We monitored the H2O disk-averaged emission at 556.936 GHz with the space telescope between 2002 and 2019, covering nearly two decades. We analyzed the data with a combination of 1D photochemical and radiative transfer models to constrain the vertical eddy diffusion in the stratosphere of Jupiter. Results. Odin observations show us that the emission of H2O has an almost linear decrease of about 40% between 2002 and 2019. We can only reproduce our time series if we increase the magnitude of Kzz in the pressure range where H2O diffuses downward from 2002 to 2019, that is, from ~0.2 mbar to ~5 mbar. However, this modified Kzz is incompatible with hydrocarbon observations. We find that even if an allowance is made for the initially large abundances of H2O and CO at the impact latitudes, the photochemical conversion of H2O to CO2 is not sufficient to explain the progressive decline of the H2O line emission, which is suggestive of additional loss mechanisms. Conclusions. The Kzz we derived from the Odin observations of H2O can only be viewed as an upper limit in the ~0.2 mbar to ~5 mbar pressure range. The incompatibility between the interpretations made from H2O and hydrocarbon observations probably results from 1D modeling limitations. Meridional variability of H2O, most probably at auroral latitudes, would need to be assessed and compared with that of hydrocarbons to quantify the role of auroral chemistry in the temporal evolution of the H2O abundance since the SL9 impacts. Modeling the temporal evolution of SL9 species with a 2D model would naturally be the next step in this area of study.
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| 3. |
- Cabrera, C., et al.
(författare)
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Relationship between iron deficiency and expression of genes involved in iron metabolism in human myocardium and skeletal muscle
- 2023
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Ingår i: International Journal of Cardiology. - : Elsevier. - 0167-5273 .- 1874-1754. ; 379, s. 82-88
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Tidskriftsartikel (refereegranskat)abstract
- Background: Iron deficiency (ID) is associated with adverse prognosis in patients with heart failure. This study aims to investigate the relationship between ID and expression of genes involved in iron metabolism in human myocardium and skeletal muscle, focusing on Transferrin 1 receptor (TfR1), the main pathway of cellular iron uptake.Methods: Patients undergoing elective CABG were assessed prior to surgery with echocardiography and serum iron parameters. Core needle biopsies were collected from the left and right ventricle (LV, RV), the right atrium and intercostal skeletal muscle (SM). Gene expression analyses were done by mRNA sequencing.Results: Of 69 patients (median age 69 years, 91% men), 28% had ID. 26% had HFrEF, 25% had HFpEF phys-iology according to echocardiographic findings and NT-proBNP levels, and 49% had normal LV function. The expression of TfR1 was increased in patients with ID compared to patients without ID in ventricular tissue (p = 0.04) and in intercostal SM (p = 0.01). The increase in TfR1 expression in LV and RV was more pronounced when analysing patients with absolute ID (S-Ferritin<100 mu g/L). Analysing the correlation between various iron pa-rameters, S-Ferritin levels showed the strongest correlation with TfR1 expression. There was no correlation with NT-proBNP levels and no difference in TfR1 expression between different HF phenotypes.Conclusions: In patients undergoing elective CABG we found an association between ID and increased TfR1 expression in myocardium regardless of LV function, indicating physiologically upregulated TfR1 expression in the presence of ID to restore intracellular iron needs.
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| 5. |
- Sandqvist, Aage, et al.
(författare)
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Herschel and Odin observations of H 2 O, CO, CH, CH + , and [N» II] in the barred spiral galaxy NGC 1365: Bar-induced activity in the outer and inner circumnuclear tori
- 2021
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 647
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Tidskriftsartikel (refereegranskat)abstract
- Context. The Odin satellite is now into its twentieth year of operation, much surpassing its design life of two years. One of its major astronomical pursuits was the search for and study of water vapor in diverse regions of the Solar System and the Milky Way galaxy. The Herschel space observatory was needed to detect water vapor in external galaxies. Aims. Our goal is to study the distribution and excitation of water vapor and other molecules in the barred spiral galaxy NGC 1365. Methods. Herschel has observed the central region of NGC 1365 in two positions, and both its SPIRE and PACS observations are available in the Herschel Science Archive. Herschel PACS images have been produced of the 70 and 160 μm infrared emission from the whole galaxy, and also of the cold dust distribution as obtained from the ratio of the 160 to 70 μm images. The Herschel SPIRE observations have been used to produce simultaneously observed maps of the 557 GHz o-H2O, 752 GHz p-H2O, 691 GHz CO(6-5), 1037 GHz CO(9-8), 537 GHz CH, 835 GHz CH+, and the 1461 GHz [N» II] lines (efficiently probing the warm ionized medium) in the inner bar and circumnuclear torus region;-however, these observations have no effective velocity resolution. For this reason Odin has recently observed the 557 GHz ortho-H2O ground state line in the central region with high (5 km s-1) spectral resolution. Results. The emission and absorption of H2O at 557 GHz, with a velocity resolution of 5 km s-1, has been marginally detected in NGC 1365 with Odin. The water vapor is predominantly located in a shocked 15″ (1.3 kpc) region near some central compact radio sources and hot-spot H» II regions, close to the northeast component of the molecular torus surrounding the nucleus. An analysis of the H2O line intensities and velocities indicates that a shock-region is located here. This is corroborated by a statistical image deconvolution of our SEST CO(3-2) observations, yielding 5″ resolution, and a study of our Very Large Array H» I absorption observations, as well as comparisons with published interferometric CO observations. Additionally, an enticing 20″ H» I ridge is found to extend south-southeast from the nucleus, coinciding in position with the southern edge of an O» III outflow cone, emanating from the nucleus. The molecular chemistry of the shocked central region of NGC 1365 is analyzed with special emphasis on the CO, H2O and CH, CH+ results. Conclusions. The dominating activity near the northeast (NE) torus component may have been triggered by the rapid bar-driven inflow into the circumnuclear torus causing cloud-cloud collisions and shocks, leading to the formation of stellar superclusters and, hence, also to more efficient PDR chemistry, which, here, may also benefit from cosmic ray focusing caused by the observed aligned magnetic field. The very high activity near the NE torus component may reflect the fact that the eastern bar-driven gas inflow into the NE region is much more massive than the corresponding western gas inflow into the southwest region. The H2O and CH+ emissions peak in the NE torus region, but the CO and CH emissions are more evenly distributed across the whole circumnuclear torus. The higher energy CO spectral line energy distribution (SLED) is nicely modeled by a low velocity (10 km s-1) shock, which may as well explain the required CH excitation and its high abundance in denser gas. The higher velocity (40 km s-1) shock required to model the H2O SLED in the NE torus region, paired with the intense UV radiation from the observed massive young stellar superclusters, may also explain the high abundance of CH+ in this region. The nuclear H» I ridge may have been created by the action of outflow-driving X-ray photons colliding with ice-covered dust grains. A precessing nuclear engine, as is suggested by the tilted massive inner gas torus, may be necessary to explain the various nuclear outflows encountered.
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