42 research outputs found
Transport of Canadian forest fire smoke over the UK as observed by lidar
Layers of aerosol at heights between 2 and 11 km were observed with Raman
lidars in the UK between 23 and 31 May 2016. A network of these lidars,
supported by ceilometer observations, is used to map the extent of the
aerosol and its optical properties. Space-borne lidar profiles show that the
aerosol originated from forest fires over western Canada around 17 May, and
indeed the aerosol properties – weak volume depolarisation ( < 5 %) and a
lidar ratio at 355 nm in the range 35–65 sr – were consistent with
long-range transport of forest fire smoke. The event was unusual in its
persistence – the smoke plume was drawn into an atmospheric block that kept
it above north-western Europe for 9 days. Lidar observations show how the
smoke layers became optically thinner during this period, but the lidar ratio
and aerosol depolarisation showed little change. The results demonstrate the
value of a dense network of observations for tracking forest fire smoke, and
show how the dispersion of smoke in the free troposphere leads to the
emergence of discrete thin layers in the far field. They also show how
atmospheric blocking can keep a smoke plume in the same geographic area for
over a week.</p
Monocyte Subset Dynamics in Human Atherosclerosis Can Be Profiled with Magnetic Nano-Sensors
Monocytes are circulating macrophage and dendritic cell precursors that populate healthy and diseased tissue. In humans, monocytes consist of at least two subsets whose proportions in the blood fluctuate in response to coronary artery disease, sepsis, and viral infection. Animal studies have shown that specific shifts in the monocyte subset repertoire either exacerbate or attenuate disease, suggesting a role for monocyte subsets as biomarkers and therapeutic targets. Assays are therefore needed that can selectively and rapidly enumerate monocytes and their subsets. This study shows that two major human monocyte subsets express similar levels of the receptor for macrophage colony stimulating factor (MCSFR) but differ in their phagocytic capacity. We exploit these properties and custom-engineer magnetic nanoparticles for ex vivo sensing of monocytes and their subsets. We present a two-dimensional enumerative mathematical model that simultaneously reports number and proportion of monocyte subsets in a small volume of human blood. Using a recently described diagnostic magnetic resonance (DMR) chip with 1 µl sample size and high throughput capabilities, we then show that application of the model accurately quantifies subset fluctuations that occur in patients with atherosclerosis