Direct observation of aqueous secondary organic aerosol from biomass-burning emissions.

The mechanisms leading to the formation of secondary organic aerosol (SOA) are an important subject of ongoing research for both air quality and climate. Recent laboratory experiments suggest that reactions taking place in the atmospheric liquid phase represent a potentially significant source of SOA mass. Here, we report direct ambient observations of SOA mass formation from processing of biomass-burning emissions in the aqueous phase.

On the water-soluble organic nitrogen concentration and mass size distribution during the fog season in the Po Valley, Italy.

The study of organic nitrogen gained importance in recent decades due to its links with acid rain, pollution, and eutrophication. In this study, aerosol and fog water samples collected from two sites in Italy during November 2011 were analyzed to characterize their organic nitrogen content. Organic nitrogen contributed 19-25% of the total soluble nitrogen in the aerosol and around 13% in fog water.

High yield patterning of single cells from extremely small populations.

Many biological assays require the ability to isolate and process single cells. Some research fields, such as the characterization of rare cells, the in vitro processing of stem cells, and the study of early stage cell differentiation, call for the additional and typically unmet ability to work with extremely low-count cell populations. In all these cases, efficient single-cell handling must be matched with the ability to work on a limited number of cells with a low cell loss rate.

Inverted open microwells for cell trapping, cell aggregate formation and parallel recovery of live cells.

The inverted open microwell is a novel microstructure supporting isolation and trapping of cells, analysis of cell-cell and cell-molecule interactions and functional cell sorting. This work introduces the inverted open microwell concept, demonstrating successful isolation of K562 cells in 75 μm microwells fabricated on a flexible printed circuit board substrate, and recovery of viable cells onto standard microtiter plates after analysis and manipulation. Dielectrophoresis (DEP) was used during the delivery phase to control cell access to the microwell and force the formation of cell aggregates so as to ensure cell-cell contact and interaction.

Horizontal nDEP cages within open microwell arrays for precise positioning of cells and particles.

We present the structure of an open microwell, i.e. a microwell open at both the top and bottom ends, which enables single-cells to be handled, processed and recovered after the experiment.