Cardiopulmonary toxicity of peat wildfire particulate matter and the predictive utility of precision cut lung slices

BackgroundEmissions from a large peat fire in North Carolina in 2008 were associated with increased hospital admissions for asthma and the rate of heart failure in the exposed population. Peat fires often produce larger amounts of smoke and last longer than forest fires, however few studies have reported on their toxicity. Moreover, reliable alternatives to traditional animal toxicity testing are needed to reduce the number of animals required for hazard identification and risk assessments.MethodsSize-fractionated particulate matter (PM; ultrafine, fine, and coarse) were obtained from the peat fire while smoldering (ENCF-1) or when nearly extinguished (ENCF-4). Extracted samples were analyzed for chemical constituents and endotoxin content. Female CD-1 mice were exposed via oropharyngeal aspiration to 100μg/mouse, and assessed for relative changes in lung and systemic markers of injury and inflammation. At 24h post-exposure, hearts were removed for ex vivo functional assessments and ischemic challenge. Lastly, 8mm diameter lung slices from CD-1 mice were exposed (11μg) ± co-treatment of PM with polymyxin B (PMB), an endotoxin-binding compound.ResultsOn an equi-mass basis, coarse ENCF-1PM had the highest endotoxin content and elicited the greatest pro-inflammatory responses in the mice including: increases in bronchoalveolar lavage fluid protein, cytokines (IL-6, TNF-α, and MIP-2), neutrophils and intracellular reactive oxygen species (ROS) production. Exposure to fine or ultrafine particles from either period failed to elicit significant lung or systemic effects. In contrast, mice exposed to ENCF-1 ultrafine PM developed significantly decreased cardiac function and greater post-ischemia-associated myocardial infarction. Finally, similar exposures to mouse lung slices induced comparable patterns of cytokine production; and these responses were significantly attenuated by PMB.ConclusionsThe findings suggest that exposure to coarse PM collected during a peat fire causes greater lung inflammation in association with endotoxin and ROS, whereas the ultrafine PM preferentially affected cardiac responses. In addition, lung tissue slices were shown to be a predictive, alternative assay to assess pro-inflammatory effects of PM of differing size and composition. Importantly, these toxicological findings were consistent with the cardiopulmonary health effects noted in epidemiologic reports from exposed populations

Gaseous Emissions of a Combined Cogeneration Unit

Problem of harmful gaseous emissions is solved in the paper in two ways. Firstly it is the design of amathematical model of flow and combustion in a combustion chamber of an engine, which is a component of a combined cogeneration unit with a proposal of solutions enabling the decrease in amount of harmful gaseous emissions. Secondly it is the verification of the solutions through the computation by means of mathematical models considering these solutions

Nucleating efficiency and thermal stability of industrial non-purified lignins and ultrafine talc in poly(lactic acid) (PLA)

Poly(lactic acid) (PLA) with D – lactide content of 1.2 wt% has been modified by melt mixing with 3 wt% of lignin (Kraft or Organosolv). Gel permeation chromatography and thermogravimetric analysis were employed to determine the thermal stability of PLA and nucleated PLA compounds during melt blending. The nucleating efficiency of industrial lignins was compared with the nucleation efficiency of ultrafine talc (UT). The feasibility of using industrial lignins and UT as nucleating agents for PLA was investigated by polarized light optical microscopy and differential scanning calorimetry, through non-isothermal and isothermal crystallization, whereas their structure was studied through in-situ synchrotron X-ray diffraction at wide and small angles. Both lignins, as well as UT induced heterogeneous nucleation and their nucleating action in PLA increased the crystallization rate and shortened the overall crystallization half time for isothermal crystallization. All tested nucleating agents increased the degree of crystallinity of PLA. The nucleation efficiency of Kraft and Organosolv lignin and ultrafine talc was 31%, 27%, and 80%, respectively. It was found that the thermal processing window of PLA was not influenced by the addition of lignins or ultrafine talc. © 2017 Elsevier LtdIWB 2014-2020, ERDF, European Regional Development Fund; LO1504, MŠMT, Ministerstvo Školství, Mládeže a TělovýchovyEuropean Regional Development Fund (EFRE); province of Upper Austria through program IWB Upper Austria; Ministry of Education, Youth and Sports of the Czech Republic [LO1504]; POLYMAT Basque Center for Macromolecular Design and Engineering; ALBA synchrotron facility [2016091863