The dissolution of stone wool fibers with sugar-based binder and oil in different synthetic lung fluids
Toxicol In Vitro. 2021 Oct 29:105270. doi: 10.1016/j.tiv.2021.105270. Online ahead of print.ABSTRACTThe biopersistence of fiber materials is one of the cornerstones in estimating potential risk to human health upon inhalation. To connect epidemiological and in vivo investigations with in vitro studies, reliable and robust methods of fiber biopersistence determination and understanding of fiber dissolution mechanism are required. We investigated dissolution properties of oil treated stone wool fibers with and without sugar-based binder (SBB) at 37 °C in the liquids representing macrophages intracellular conditions (pH 4.5). Conditions varied from batch to flow of different rates. Fiber morphology and surface chemistry changes caused by dissolution were monitored with scanning electron microscopy and time-of-flight secondary ion mass spectrometry mapping. Stone wool fiber dissolution rates depend on liquid composition (presence of ligands, such as citrate), pH, reaction products transport and fibers wetting properties. The dissolution rate decreases when: 1) citrate is consumed by the reaction with the released Al cations; 2) the pH increases during a reaction in poorly buffered solutions; 3) the dissolution products are accumulated; 4) fibers are not fully wetted with the fluid. Presence of SBB has no influence on dissolution rates if the fiber material was wetted prior to dissolution experiments to avoid poorly wetted fiber agglomerates formation in the synthetic lung flu...
Conclusion: This study found that girls with PNE performed more obvious damages on attention, executive function and working memory than boys which might be related to the fact that girls were more likely to suffer from confidence impairment due to enuresis leading to cognitive dysfunctions. The method of ALFF based on resting-state fMRI provided a new approach for studying the cognitive characteristics of PNE children.
ConclusionAn extramural vaginal ectopic ureter is better accessed through transvaginal approach than abdominal, especially when it is associated with pelvic ectopic kidney. This modified approach is less invasive and has lower morbidity and better success rate than a transabdominal approach.
CONCLUSION: Although significant topographic differences were present between machined and sandblasted disks, the Streptococcus oralis biofilm formation seems to not be significantly affected.PMID:34698719 | DOI:10.11607/jomi.8739