The analysis of parameters in bronchoalveolar extracellular lining secretions has come into greater use in the diagnosis of diseases of the lung and respiratory passages. The bronchoalveolar lavage (BAL) method is thus used for sampling alveolar fluids or bronchial secretions. However, this method is invasive and therefore cannot be routinely employed for probe sampling. Based on the hypothesis that aerosol particles excreted in human breath reflect the composition of the bronchoalveolar extracellular lining fluid, experiments were performed to concentrate and analyze these aerosols directly using a noninvasive technique. Human exhaled air was directed through a set of cool traps and the condensate of 200 to 400 exhalations examined for nonvolatile components, such as proteins. In experiments conducted with volunteers, the amount of proteins in the breath condensate of 8 healthy individuals (of a total of 10) amounted to between 4 micrograms and 1.4 mg. The proteins were separated by two-dimensional polyacrylamide gel electrophoresis (PAGE) and compared to saliva samples of the respective volunteers. The results suggest that the proteins detected in breath originate partially from the naso-oropharyngeal tract and partially from lower regions of the airways. In clinical tests, the exhaled air of 13 patients suffering from various diseases of the respiratory tract was sampled and analyzed by immunoassays for inflammation parameters, such as interleukin-1 beta (IL-1 beta), soluble interleukin-2 receptor protein, light chain (sIL-2R), interleukin-6 (IL-6), and tumor necrosis factor alpha (TNF-alpha). In these tests, up to 370 pg IL-1 beta, 120 pg TNF-alpha, and 2,159 U sIL-2R per ml were measured in the breath condensate.(ABSTRACT TRUNCATED AT 250 WORDS)
The increasing dependence on more robust additive chemistry to improve gear pitting resistance requires the additive technology development to rely less on a trial-and-error approach and more on a better basic understanding of the influence of additive chemistry on tribological contact layers' physical and chemical changes. The use of secondary neutral mass spectrometry (SNMS) and nanoindenter to analyse tribological contact layers had been carried out by Inacker and co-workers at NMI. They found that the alkyl structure of zinc dithiophosphate (ZDTP) and the type of cation have a profound effect on the thickness and nanohardness of the tribological layer. An extension to that study has been carried out in this investigation, which involves a design experiment of two variables (oil viscosity and surface roughness) while keeping the additive chemistry constant to determine their impact on the tribological layer. The methods used to analyse the tribological layers include SNMS, nanoindenter and SEM coupled with focused ion beam imaging of the rectangular well-shaped cross section. The results in general are in agreement with the findings of Inacker and his co-workers, namely greater micropitting reduces the thickness of the tribological layer and brings closer the depth of nanohardness maximum to the surface.
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