15 research outputs found

    ISO-SWS calibration and the accurate modelling of cool-star atmospheres - II. General results

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    The fine calibration of the ISO-SWS detectors (Infrared Space Observatory - Short Wavelength Spectrometer) has proven to be a delicate problem. We therefore present a detailed spectroscopic study in the 2.38 -- 12 micron wavelength range of a sample of 16 A0 -- M2 stars used for the calibration of ISO-SWS. By investigating the discrepancies between the ISO-SWS data of these sources, the theoretical predictions of their spectra, the high-resolution FTS-KP (Kitt Peak) spectrum of Alpha Boo and the solar FTS-ATMOS (Atmospheric Trace Molecule Spectroscopy) spectrum, both calibration problems and problems in computing the theoretical models and the synthetic spectra are revealed. The underlying reasons for these problems are sought for and the impact on the further calibration of ISO-SWS and on the theoretical modelling is discussed extensively.Comment: 17 pages, 19 figures; Astronomy and Astrophysics, in press; preprints can be obtained by contacting [email protected] or via WWW on http://www.ster.kuleuven.ac.be/~leen or via anonymous ftp on ftp://ftp.ster.kuleuven.ac.be/dist/leen/latex/h3317 Appendix electronically available (3 pages, 7 figures

    IRAK4 gene polymorphism and odontogenic maxillary sinusitis

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    Objectives This study aimed to evaluate whether a specific interleukin-1 receptor-associated kinase-4 (IRAK4) gene polymorphism had any influence on the development of changes in maxillary sinus, particularly in the presence of etiological factors of dental origin.Materials and methods The study population included 153 Portuguese Caucasians that were selected from a database of 504 retrospectively analysed computed tomography (CT) scans. A genetic test was performed, and a model was created through logistic analysis and regression coefficients. The statistical methodologies included were the independent Chi test, Fisher's exact test, binary logistic regression and the receiver operating characteristic (ROC) curve.Results The estimated prevalence of IRAK4 gene polymorphism found in a Portuguese Caucasian population was 26.8 % (CI 95 %) [20.1, 34.7 %]. A model to predict the inflammatory response in the maxillary sinus in the presence etiological factors of dental origin was constructed. This model had the following as variables: previously diagnosed sinusitis, sinus pressure symptoms, cortical bone loss observed on CT, positive genetic test result and radiographic examination that revealed the roots of the teeth communication with the maxillary sinus, which are interpreted as risk factors.Conclusions The constructed model should be considered an initial clinical tool. The area under the ROC curve found, AUC=0.91, revealed that the model correctly predicts the outcome in 91.1 % of cases.info:eu-repo/semantics/publishedVersio

    Impaired antiviral response in human hepatoma cells

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    AbstractHepatitis B, C, and D viruses can infect liver cells and in some individuals establish a chronic phase of infection. Presently, relatively little information is available on the antiviral mechanisms in liver cells. Because no good in vitro model infection systems for hepatitis viruses are available, we have used influenza A, Sendai, and vesicular stomatitis (VSV) viruses to characterize interferon (IFN) responses and IFN-induced antiviral mechanisms in human hepatoma cell lines. HepG2 or HuH7 cells did not show any detectable IFN-α/β production in response to influenza A or Sendai virus infections. Treatment of cells with IFN-α resulted in upregulation of IFN-α-inducible Mx, 2′,5′-oligoadenylate synthetase (OAS) and HLA class I gene expression but only with exceptionally high levels of IFN-α (≥100 IU/ml). Accordingly, high pretreatment levels of IFN-α, 1000 IU/ml for influenza A and VSV and 100 IU/ml for Sendai virus, were required before any detectable antiviral activity against these viruses was seen. IFN-γ had some antiviral effect against influenza A virus but appeared to be ineffective against VSV and Sendai virus. IFN-γ upregulated HLA class I protein expression, whereas Mx or OAS expression levels were not increased. There was a modest upregulation of HLA class I expression during Sendai virus infection, whereas influenza A virus infection resulted, after an initial weak upregulation, in a clear decrease in HLA class I expression at late times of infection. The results suggest that hepatoma cells may have intrinsically poor ability to produce and respond to type I IFNs, which may contribute to their inability to efficiently resist viral infections

    Hydrogen fluoride total and partial column time series above the Jungfraujoch from long-term FTIR measurements: Impact of the line-shape model, characterization of the error budget and seasonal cycle, and comparison with satellite and model data

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    Time series of hydrogen fluoride (HF) total columns have been derived from ground-based Fourier transform infrared (FTIR) solar spectra recorded between March 1984 and December 2009 at the International Scientific Station of the Jungfraujoch (Swiss Alps, 46.5°N, 8.0°E, 3580 m asl) with two high resolution spectrometers (one home-made and one Bruker 120-HR). Solar spectra have been inverted with the PROFFIT 9.5 algorithm, using the optimal estimation method. An inter-comparison of HF total columns retrieved with PROFFIT and SFIT-2 – the other reference algorithm in the FTIR community - is performed for the first time. The effect of a Galatry line shape model on HF retrieved total columns and vertical profiles, on the residuals of the fits and on the error budget is also quantified. Information content analysis indicates that, in addition to HF total vertical abundance, three independent stratospheric HF partial columns can be derived from our Bruker spectra. A complete error budget has been established and indicates that the main source of systematic error is linked to HF spectroscopy and that the random error affecting our HF total columns does not exceed 2.5%. Ground-based middle and upper stratospheric HF amounts have been compared to satellite data collected by the HALOE or ACE-FTS instruments. Comparisons of our FTIR HF total and partial columns with runs performed by two 3D numerical models (SLIMCAT and KASIMA) are also included. Finally, FTIR and model HF total and partial columns time series have been analyzed to derive the main characteristics of their seasonal cycles

    Early-life respiratory tract infections and the risk of school-age lower lung function and asthma: a meta-analysis of 150 000 European children.

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    BACKGROUND: Early-life respiratory tract infections might affect chronic obstructive respiratory diseases, but conclusive studies from general populations are lacking. OBJECTIVE: To examine if children with early-life respiratory tract infections had increased risks of lower lung function and asthma at school-age. METHODS: We used individual-participant data of 150 090 children primarily from the EU Child Cohort Network to examine the associations of upper and lower respiratory tract infections from age 6 months to 5 years with forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), FEV1/FVC, forced expiratory flow at 75% of FVC (FEF75), and asthma at a median age of 7 (range 4 to 15) years. RESULTS: Children with early-life lower, not upper, respiratory tract infections had a lower school-age FEV1, FEV1/FVC and FEF75 (Z-score (95% CI): ranging from -0.09 (-0.14, -0.04) to -0.30 (-0.36, -0.24)). Children with early-life lower respiratory tract infections had a higher increased risk of school-age asthma than those with upper respiratory tract infections (OR (95%CI): ranging from 2.10 (1.98, 2.22) to 6.30 (5.64, 7.04)), and from 1.25 (1.18, 1.32) to 1.55 (1.47, 1.65)), respectively). Adjustment for preceding respiratory tract infections slightly decreased the strength of the effects. Observed associations were similar for those with and without early-life wheezing as proxy for early-life asthma. CONCLUSION: Our findings suggest that early-life respiratory tract infections affect development of chronic obstructive respiratory diseases in later life, with the strongest effects for lower upper respiratory tract infections
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