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| 2. |
- Lebzelter, T., et al.
(författare)
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Comparative modelling of the spectra of cool giants
- 2012
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 547, s. A108-
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Tidskriftsartikel (refereegranskat)abstract
- Context. Our ability to extract information from the spectra of stars depends on reliable models of stellar atmospheres and appropriate techniques for spectral synthesis. Various model codes and strategies for the analysis of stellar spectra are available today. Aims. We aim to compare the results of deriving stellar parameters using different atmosphere models and different analysis strategies. The focus is set on high-resolution spectroscopy of cool giant stars. Methods. Spectra representing four cool giant stars were made available to various groups and individuals working in the area of spectral synthesis, asking them to derive stellar parameters from the data provided. The results were discussed at a workshop in Vienna in 2010. Most of the major codes currently used in the astronomical community for analyses of stellar spectra were included in this experiment. Results. We present the results from the different groups, as well as an additional experiment comparing the synthetic spectra produced by various codes for a given set of stellar parameters. Similarities and differences of the results are discussed. Conclusions. Several valid approaches to analyze a given spectrum of a star result in quite a wide range of solutions. The main causes for the differences in parameters derived by different groups seem to lie in the physical input data and in the details of the analysis method. This clearly shows how far from a definitive abundance analysis we still are.
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| 6. |
- Andersson, I., et al.
(författare)
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Human MxA Protein Inhibits the Replication of Crimean-Congo Hemorrhagic Fever Virus
- 2004
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Ingår i: Journal of Virology. - 0022-538X .- 1098-5514. ; 78:8, s. 4323-4329
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Tidskriftsartikel (refereegranskat)abstract
- Crimean-Congo hemorrhagic fever virus (CCHFV) belongs to the genus Nairovirus within the family Bunyaviridae and is the causative agent of severe hemorrhagic fever. Despite increasing knowledge about hemorrhagic fever viruses, the factors determining their pathogenicity are still poorly understood. The interferon-induced MxA protein has been shown to have an inhibitory effect on several members of the Bunyaviridae family, but the effect of MxA against CCHFV has not previously been studied. Here, we report that human MxA has antiviral activity against CCHFV. The yield of progeny virus in cells constitutively expressing MxA was reduced up to 1,000-fold compared with control cells, and accumulation of viral genomes was blocked. Confocal microscopy revealed that MxA colocalizes with the nucleocapsid protein (NP) of CCHFV in the perinuclear regions of infected cells. Furthermore, we found that MxA interacted with NP by using a coimmunoprecipitation assay. We also found that an amino acid substitution (E645R) within the C-terminal domain of MxA resulted in a loss of MxA antiviral activity and, concomitantly, in the capacity to interact with CCHFV NP. These results suggest that MxA, by interacting with a component of the nucleocapsid, prevents replication of CCHFV viral RNA and thereby inhibits the production of new infectious virus particles.
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| 7. |
- Erlandsson, A C, et al.
(författare)
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Herpes simplex virus type 1 infection and glucocorticoid treatment regulate viral yield, glucocorticoid receptor and NF-kappaB levels.
- 2002
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Ingår i: The Journal of endocrinology. - : Bioscientifica. - 0022-0795 .- 1479-6805. ; 175:1, s. 165-76
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Tidskriftsartikel (refereegranskat)abstract
- The interplay between the endocrine and immune systems has come into focus in recent years with the insight that endocrine parameters may affect susceptibility to both auto-immune and infectious diseases. Our interest in immunoendocrine regulation led us to investigate the effects of glucocorticoids on Herpes simplex virus type 1 (HSV-1) infections. Glucocorticoids used to treat inflammatory conditions are not yet recommended for HSV-1 therapy, since they have been reported to prolong viral shedding both in vivo and in vitro. Here we report that glucocorticoids did not alter the viral yield in human gingival fibroblast (HGF) cell culture when glucocorticoid treatment and viral infection occured simultaneously, but the viral yield increased when cells were treated with the glucocorticoid dexamethasone (dex) prior to viral infection. We found that viral infection in our primary cell system increased NF-kappaB levels and DNA binding. In addition, the amount of glucocorticoid receptor (GR) increased following viral infection, and HSV-1 infection as such could induce glucocorticoid-driven transcription of a reporter gene in human embryo kidney (HEK) 293 cells stably transfected with GR. Dex treatment did not affect HSV-1-induced binding of p65 to an NF-kappaB element in an electrophoretic mobility shift assay, and acyclovir was still efficient as an anti-viral drug in the presence of dex. Further studies of the observed effects of HSV-1 infection and glucocorticoid treatment on GR and NF-kappaB regulation could give insights into the immunoendocrine mechanisms important for defence and therapy against viral infections.
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| 8. |
- Michelsen, H. A., et al.
(författare)
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Modeling laser-induced incandescence of soot: a summary and comparison of LII models
- 2007
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Ingår i: Applied Physics B. - : Springer Science and Business Media LLC. - 0946-2171 .- 1432-0649. ; 87:3, s. 503-521
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Tidskriftsartikel (refereegranskat)abstract
- We have performed a comparison of ten models that predict the temporal behavior of laser-induced incandescence (LII) of soot. In this paper we present a summary of the models and comparisons of calculated temperatures, diameters, signals, and energy-balance terms. The models were run assuming laser heating at 532 nm at fluences of 0.05 and 0.70 J/cm(2) with a laser temporal profile provided. Calculations were performed for a single primary particle with a diameter of 30 nm at an ambient temperature of 1800 K and a pressure of 1 bar. Preliminary calculations were performed with a fully constrained model. The comparison of unconstrained models demonstrates a wide spread in calculated LII signals. Many of the differences can be attributed to the values of a few important parameters, such as the refractive-index function E(m) and thermal and mass accommodation coefficients. Constraining these parameters brings most of the models into much better agreement with each other, particularly for the low-fluence case. Agreement among models is not as good for the high-fluence case, even when selected parameters are constrained. The reason for greater variability in model results at high fluence appears to be related to solution approaches to mass and heat loss by sublimation.
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- Sperling, L, et al.
(författare)
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How to identify twins at low risk of spontaneous preterm delivery
- 2005
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Ingår i: Ultrasound in Obstetrics & Gynecology. - : Wiley. - 1469-0705 .- 0960-7692. ; 26:2, s. 138-144
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Tidskriftsartikel (refereegranskat)abstract
- Objective The aim of this study was to evaluate transvaginal sonograpbic assessment of cervical length at 23 weeks as a screening test for spontaneous preterm delivery in order to define a cut-off value that could be used to select twin pregnancies at low risk of spontaneous preterm delivery. Methods In a prospective multicenter study of 383 twin pregnancies included before 14 + 6 weeks a cervical scan with measurement of the cervical length was performed at 23 weeks' gestation. The results were blinded for the clinicians if the cervical length was >= 15 mm. The rates of spontaneous delivery at different cut-off levels of cervical length were determined. Results Eighty-nine percent of the twins had dichorionic placentation and 58% were conceived after assisted reproduction. The rate of spontaneous preterm delivery was 2.3% (1.5% for dichorionic (DC) and 9.1% for (MC) monochorionic twins) before 28 weeks and 18.5% (17.1% for DC and 29.5% for MC twins) before 35 weeks. The screen-positive rate was 5% for a cervical length <= 20, 7-8% at <= 25, 16-17% at <= 30 and 34-48% at <= 35mm depending on chorionicity. The false-negative rate (1 - negative predictive value) ranged from 1.2% at 28 weeks to 18.6% at 35 weeks for all twins. Receiver-operating characteristics curves showed that the sensitivity increased with declining gestation I age with cut-off levels of highest accuracy at 21 mm for 28 weeks and 29 mm for 33 weeks. Conclusions Cervical length measurement at 23 weeks of gestation is a good screening test for predicting twins at low risk of preterm and very preterm delivery, especially in DC twins. The present results suggest that a cut-off of 25 mm should be recommended.
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