24 research outputs found
Across-shift changes in upper airways after exposure to bacterial cell wall components
Introduction. To assess the across-shift changes of cytokine concentrations in nasal lavage (NAL) samples were collected
from workers exposed to bacterial cell wall components present in organic dust in three different occupational environments.
Materials and method. The study was conducted in 38 employees including 10 workers from a municipal waste sorting
plant (WSP), 20 from a sewage treatment plant (STP) and 8 from an office building (OB), who were established as a reference
group, not exposed to organic dust. Interleukins 1β (IL-1β), 6 (IL-6), 8 (IL-8) and tumour necrosis factor alpha (TNF-α) were
examined in NAL before and after work shift on Wednesdays. Bioaerosol exposure was determined by personal measurements
and analysed for organic dust, endotoxins (END) and peptidoglycans (PGN).
Results. The analysis included the results for IL-8 only, because for the other cytokines their concentrations in 80% of cases
were below the detection level. The most polluted were the workplaces in WSP with average concentrations of organic
dust – 3.47 mg/m3, END – 96.31 ng/m3 and PGN – 571.88 ng/m3. The results of IL-8 showed a significant difference between
the studied groups after the work shift (p=0.007). Among WSP workers concentrations of IL-8 increased also significantly
(p=0.015) during the work shift. Multivariate analysis showed that organic dust and END were the factors that in the most
distinct way (p<0.001) influenced changes of IL-8 levels in NAL.
Conclusions. Each alteration in the composition of bioaerosols will probably determine the changes in the mechanisms
responsible for both formation and modulation of inflammatory reactions in exposed workers
Longitudinal multiple-trait versus cumulative single-trait analysis of male and female fertility and hatchability in chickens
Male and female fertility and hatchability in chickens: a longitudinal mixed model approach
Equivalent diffusion coefficient and equivalent diffusion accessible porosity of a stratified porous medium
Diffusion is an important transport process in low permeability media, which play an important role in contamination and remediation of natural environments. The calculation of equivalent diffusion parameters has however not been extensively explored. In this paper, expressions of the equivalent diffusion coefficient and the equivalent diffusion accessible porosity normal to the layering in a layered porous medium are derived based on analytical solutions of the diffusion equation. The expressions show that the equivalent diffusion coefficient changes with time. It is equal to the power average with p = -0.5 for small times and converges to the harmonic average for large times. The equivalent diffusion accessible porosity is the harmonic average of the porosities of the individual layers for all times. The expressions are verified numerically for several test cases
Steps toward determination of the size and structure of the broad-line region in active galactic nuclei. I. An 8 month campaign of monitoring NGC 5548 with IUE
This is an electronic version of an article published in The Astrophysical Journal. Clavel, J. et al. Steps toward determination of the size and structure of the broad-line region in active galactic nuclei. I. An 8 month campaign of monitoring NGC 5548 with IUE. The Astrophysical Journal 366 (1991): 64-8
Steps toward Determination of the Size and Structure of the Broad-Line Region in Active Galactic Nuclei. IX. Ultraviolet Observations of Fairall 9
An 8 month monitoring campaign on the Seyfert 1 galaxy Fairall 9 has been conducted with the International Ultraviolet Explorer in an attempt to obtain reliable estimates of continuum-continuum and continuumÈemission-line delays for a high-luminosity active galactic nucleus (AGN). While the results of this campaign are more ambiguous than those of previous monitoring campaigns on lower luminosity sources, we Ðnd general agreement with the earlier results : (1) there is no measurable lag between ultraviolet continuum bands, and (2) the measured emission-line time lags are very short. It is especially notable that the Lyα + N V emission-line lag is about 1 order of magnitude smaller than determined from a previous campaign by Clavel, Wamsteker, & Glass (1989) when Fairall 9 was in a more luminous state. In other well-monitored sources, speciÐcally NGC 5548 and NGC 3783, the highest ionization lines are found to respond to continuum variations more rapidly than the lower ionization lines, which suggests a radially ionization-stratified broad-line region. In this case, the results are less certain, since none of the emission-line lags are very well determined. The best-determined emission line lag is Lyα + N V, for which we find that the centroid of the continuum—emission-line crosscorrelation function is tcent ≈14—20 days. We measure a lag tcent<~4 days for He II λ1640; this result is consistent with the ionization-stratification pattern seen in lower luminosity sources, but the relatively large uncertainties in the emission-line lags measured here cannot rule out similar lags for Lyα + N V and He II λ1640 at a high level of significance. We are unable to determine a reliable lag for C IV λ1550, but we note that the profiles of the variable parts of Lyα and C IV λ1550 are not the same, which does not support the hypothesis that the strongest variations in these two lines arise in the same region