82 resultados para Dust Flame Acceleration
em BORIS: Bern Open Repository and Information System - Berna - Suiça
Resumo:
ROTEM® is considered a helpful point-of-care device to monitor blood coagulation in emergency situations. Centrally performed analysis is desirable but rapid transport of blood samples is an important prerequisite. The effect of acceleration forces on sample transport through a pneumatic tube system on ROTEM® should be tested at each institution to exclude a pre-analytical influence. The aims of the present work were: (i) to investigate the effect of pneumatic tube transport on ROTEM® parameters; (ii) to compare blood sample transport via pneumatic tube vs. manual transportation; and (iii) to determine the effect of acceleration forces on ROTEM® parameters.
Resumo:
Background Predominantly, studies of nanoparticle (NPs) toxicology in vitro are based upon the exposure of submerged cell cultures to particle suspensions. Such an approach however, does not reflect particle inhalation. As a more realistic simulation of such a scenario, efforts were made towards direct delivery of aerosols to air-liquid-interface cultivated cell cultures by the use of aerosol exposure systems. This study aims to provide a direct comparison of the effects of zinc oxide (ZnO) NPs when delivered as either an aerosol, or in suspension to a triple cell co-culture model of the epithelial airway barrier. To ensure dose–equivalence, ZnO-deposition was determined in each exposure scenario by atomic absorption spectroscopy. Biological endpoints being investigated after 4 or 24h incubation include cytotoxicity, total reduced glutathione, induction of antioxidative genes such as heme-oxygenase 1 (HO–1) as well as the release of the (pro)-inflammatory cytokine TNFα. Results Off-gases released as by-product of flame ZnO synthesis caused a significant decrease of total reduced GSH and induced further the release of the cytokine TNFα, demonstrating the influence of the gas phase on aerosol toxicology. No direct effects could be attributed to ZnO particles. By performing suspension exposure to avoid the factor “flame-gases”, particle specific effects become apparent. Other parameters such as LDH and HO–1 were not influenced by gaseous compounds: Following aerosol exposure, LDH levels appeared elevated at both timepoints and the HO–1 transcript correlated positively with deposited ZnO-dose. Under submerged conditions, the HO–1 induction scheme deviated for 4 and 24h and increased extracellular LDH was found following 24h exposure. Conclusion In the current study, aerosol and suspension-exposure has been compared by exposing cell cultures to equivalent amounts of ZnO. Both exposure strategies differ fundamentally in their dose–response pattern. Additional differences can be found for the factor time: In the aerosol scenario, parameters tend to their maximum already after 4h of exposure, whereas under submerged conditions, effects appear most pronounced mainly after 24h. Aerosol exposure provides information about the synergistic interplay of gaseous and particulate phase of an aerosol in the context of inhalation toxicology. Exposure to suspensions represents a valuable complementary method and allows investigations on particle-associated toxicity by excluding all gas–derived effects.
Resumo:
House dust mites can be found all over the world where human beings live independent from the climate. Proteins from the gastrointestinal tract- almost all known as enzymes - are the allergens which induce chronic allergic diseases. The inhalation of small amounts of allergens on a regular base all night leads to a slow beginning of the disease with chronically stuffed nose and an exercise induced asthma which later on persists. House dust mites grow well in a humid climate - this can be in well isolated dwellings or in the tropical climate - and nourish from human skin dander. Scales are found in mattresses, upholstered furniture and carpets. The clinical picture with slowly aggravating complaints leads quite often to a delayed diagnosis, which is accidently done on the occasion of a wider spectrum of allergy skin testing. The beginning of a medical therapy with topical steroids as nasal spray or inhalation leads to a fast relief of the complaints. Although discussed in extensive controversies in the literature - at least in Switzerland with the cold winter and dry climate - the recommendation of house dust mite avoidance measures is given to patients with good clinical results. The frequent ventilation of the dwelling with cold air in winter time cause a lower indoor humidity. Covering encasings on mattresses, pillow, and duvets reduces the possibility of chronic contact with mite allergens as well as the weekly changing the bed linen. Another option of therapy is the specific immunotherapy with extracts of house dust mites showing good results in children and adults. Using recombinant allergens will show a better quality in diagnostic as well as in therapeutic specific immunotherapy.
Resumo:
Ice core data from Antarctica provide detailed insights into the characteristics of past climate, atmospheric circulation, as well as changes in the aerosol load of the atmosphere. We present high-resolution records of soluble calcium (Ca2+), non-sea-salt soluble calcium (nssCa2+), and particulate mineral dust aerosol from the East Antarctic Plateau at a depth resolution of 1 cm, spanning the past 800 000 years. Despite the fact that all three parameters are largely dust-derived, the ratio of nssCa2+ to particulate dust is dependent on the particulate dust concentration itself. We used principal component analysis to extract the joint climatic signal and produce a common high-resolution record of dust flux. This new record is used to identify Antarctic warming events during the past eight glacial periods. The phasing of dust flux and CO2 changes during glacial-interglacial transitions reveals that iron fertilization of the Southern Ocean during the past nine glacial terminations was not the dominant factor in the deglacial rise of CO2 concentrations. Rapid changes in dust flux during glacial terminations and Antarctic warming events point to a rapid response of the southern westerly wind belt in the region of southern South American dust sources on changing climate conditions. The clear lead of these dust changes on temperature rise suggests that an atmospheric reorganization occurred in the Southern Hemisphere before the Southern Ocean warmed significantly.