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- Weigelt, G., et al.
(författare)
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VLTI-MATISSE chromatic aperture-synthesis imaging of eta Carinae's stellar wind across the Br alpha line Periastron passage observations in February 2020
- 2021
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 652
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Tidskriftsartikel (refereegranskat)abstract
- Context. Eta Carinae is a highly eccentric, massive binary system (semimajor axis similar to 15.5 au) with powerful stellar winds and a phase-dependent wind-wind collision (WWC) zone. The primary star, eta Car A, is a luminous blue variable (LBV); the secondary, eta Car B, is a Wolf-Rayet or O star with a faster but less dense wind. Aperture-synthesis imaging allows us to study the mass loss from the enigmatic LBV eta Car. Understanding LBVs is a crucial step toward improving our knowledge about massive stars and their evolution. Aims. Our aim is to study the intensity distribution and kinematics of eta Car's WWC zone. Methods. Using the VLTI-MATISSE mid-infrared interferometry instrument, we perform Br alpha imaging of eta Car's distorted wind. Results. We present the first VLTI-MATISSE aperture-synthesis images of eta Car A's stellar windin several spectral channels distributed across the Br alpha 4.052 mu m line (spectral resolving power R similar to 960). Our observations were performed close to periastron passage in February 2020 (orbital phase similar to 14.0022). The reconstructed iso-velocity images show the dependence of the primary stellar wind on wavelength or line-of-sight (LOS) velocity with a spatial resolution of 6 mas (similar to 14 au). The radius of the faintest outer wind regions is similar to 26 mas (similar to 60 au). At several negative LOS velocities, the primary stellar wind is less extended to the northwest than in other directions. This asymmetry is most likely caused by the WWC. Therefore, we see both the velocity field of the undisturbed primary wind and the WWC cavity. In continuum spectral channels, the primary star wind is more compact than in line channels. A fit of the observed continuum visibilities with the visibilities of a stellar wind CMFGEN model (CMFGEN is an atmosphere code developed to model the spectra of a variety of objects) provides a full width at half maximum fit diameter of the primary stellar wind of 2.84 +/- 0.06 mas (6.54 +/- 0.14 au). We comparethe derived intensity distributions with the CMFGEN stellar wind model and hydrodynamic WWC models.
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| 2. |
- Eberle, L., et al.
(författare)
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Data-driven tiered procedure for enhancing yield in drug product manufacturing
- 2016
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Ingår i: Computers and Chemical Engineering. - : Elsevier BV. - 0098-1354. ; 87, s. 82-94
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Tidskriftsartikel (refereegranskat)abstract
- Enhancing efficiency of pharmaceutical batch production processes is an important challenge in times of increasing public pressure on healthcare costs and decreasing research productivity. This study presents a data-based procedure for systematic yield enhancements in drug product manufacturing, based on four steps. On the first step, production is reviewed to select relevant loss causes, which are assessed on the second step deductively with the goal of assigning measurable parameters. Descriptive Statistical Modelling of loss causes is then performed on the third step, enabling model-based enhancements of processes on the fourth step or, if necessary, a loop-back review of a given loss cause. An industrial case study was performed on production data of 88 batches and demonstrated the applicability of the procedure by prioritizing relevant loss causes, reducing required sample quantities by up to 8% and a cosmetic defect by about 70% by a process change.
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| 5. |
- Vogel, Christian, et al.
(författare)
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Imaging in Suspected Renal-Cell Carcinoma : Systematic Review
- 2019
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Ingår i: Clinical Genitourinary Cancer. - : Elsevier. - 1558-7673 .- 1938-0682. ; 17:2, s. E345-E355
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Forskningsöversikt (refereegranskat)abstract
- Objective: To systematically assessed the diagnostic performance of contrast-enhanced computed tomography (CT) compared to other imaging modalities for diagnosing and staging renal-cell carcinoma in adults.Methods: A comprehensive literature search was conducted through various electronic databases. Data from the selected studies were extracted and pooled, and median sensitivity and specificity were calculated wherever possible. Forty studies analyzing data of 4354 patients were included. They examined CT, magnetic resonance imaging (MRI), positron emission tomography-CT, and ultrasound (US).Results: For CT, median sensitivity and specificity were 88% (interquartile range [IQR] 81%-94%) and 75% (IQR 51%-90%), and for MRI they were 87.5% (IQR 75.25%-100%) and 89% (IQR 75%-96%). Staging sensitivity and specificity for CT were 87% and 74.5%, while MRI showed a median sensitivity of 90% and specificity of 75%. For US, the results varied greatly depending on the corresponding technique. Contrast-enhanced US had a median diagnostic sensitivity of 93% (IQR 88.75%-98.25%) combined with mediocre specificity. The diagnostic performance of unenhanced US was poor. For positron emission tomography-CT, diagnostic accuracy values were good but were based on only a small amount of data. Limitations include the strong heterogeneity of data due to the large variety in imaging techniques and tumor histotypes. Contrast-enhanced CT and MRI remain the diagnostic mainstay for renal-cell carcinoma, with almost equally high diagnostic and staging accuracy.Conclusion: For specific questions, a combination of different imaging techniques such as CT or MRI and contrast-enhanced US may be useful. There is a need for future large prospective studies to further increase the quality of evidence.
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