2 research outputs found
Particle Emissions from a Marine Engine: Chemical Composition and Aromatic Emission Profiles under Various Operating Conditions
The
chemical composition of particulate matter (PM) emissions from
a medium-speed four-stroke marine engine, operated on both heavy fuel
oil (HFO) and distillate fuel (DF), was studied under various operating
conditions. PM emission factors for organic matter, elemental carbon
(soot), inorganic species and a variety of organic compounds were
determined. In addition, the molecular composition of aromatic organic
matter was analyzed using a novel coupling of a thermal-optical carbon
analyzer with a resonance-enhanced multiphoton ionization (REMPI)
mass spectrometer. The polycyclic aromatic hydrocarbons (PAHs) were
predominantly present in an alkylated form, and the composition of
the aromatic organic matter in emissions clearly resembled that of
fuel. The emissions of species known to be hazardous to health (PAH,
Oxy-PAH, N-PAH, transition metals) were significantly higher from
HFO than from DF operation, at all engine loads. In contrast, DF usage
generated higher elemental carbon emissions than HFO at typical load
points (50% and 75%) for marine operation. Thus, according to this
study, the sulfur emission regulations that force the usage of low-sulfur
distillate fuels will also substantially decrease the emissions of
currently unregulated hazardous species. However, the emissions of
soot may even increase if the fuel injection system is optimized for
HFO operation
Genetic associations at 53 loci highlight cell types and biological pathways relevant for kidney function
Reduced glomerular filtration rate defines chronic kidney disease and is associated with cardiovascular and all-cause mortality. We conducted a meta-analysis of genome-wide association studies for estimated glomerular filtration rate (eGFR), combining data across 133,413 individuals with replication in up to 42,166 individuals. We identify 24 new and confirm 29 previously identified loci. Of these 53 loci, 19 associate with eGFR among individuals with diabetes. Using bioinformatics, we show that identified genes at eGFR loci are enriched for expression in kidney tissues and in pathways relevant for kidney development and transmembrane transporter activity, kidney structure, and regulation of glucose metabolism. Chromatin state mapping and DNase I hypersensitivity analyses across adult tissues demonstrate preferential mapping of associated variants to regulatory regions in kidney but not extra-renal tissues. These findings suggest that genetic determinants of eGFR are mediated largely through direct effects within the kidney and highlight important cell types and biological pathways