Hybrid capillary-inserted microfluidic device for sheathless particle focusing and separation in viscoelastic flow

A novel microfluidic device which consists of two stages for particle focusing and separation using a viscoelastic fluid has been developed. A circular capillary tube was used for three-dimensional particle pre-alignment before the separation process, which was inserted in a polydimethylsiloxane microchannel. Particles with diameters of 5 and 10 μm were focused at the centerline in the capillary tube, and the location of particles was initialized at the first bifurcation. Then, 5 and 10 μm particles were successfully separated in the expansion region based on size-dependent lateral migration, with ∼99% separation efficiency. The proposed device was further applied to separation of MCF-7 cells from leukocytes. Based on the cell size distribution, an approximate size cutoff for separation was determined to be 16 μm. At 200 μl/min, 94% of MCF-7 cells were separated with the purity of ∼97%. According to the trypan blue exclusion assay, high viability (∼90%) could be achieved for the separated MCF-7 cells. The use of a commercially available capillary tube enables the device to be highly versatile in dealing with particles in a wide size range by using capillary tubes with different inner diameters.     

Creativity and regional innovation: Evidence from EU regions

We analyse the role of creative workers in the region as a source and foundational element of regional innovation in the European Union. We show the empirical relevance of this factor – which we label inspiration – within the structure of a recursive model of regional innovation for a set of 83 European regions. We show that, when differentiated from the presence of regional intelligence – as measured by the availability of human capital – and from technological infrastructure, inspiration, along with the degree of development of national and regional institutions, has the strongest direct and indirect effects on regional patenting activity.     

Communication channels within ethnic groups

Major channels of communication are examined for two major functions: providing news of the ethnic community, and linking ethnics to the “mother country.” The four major channels are: interpersonal channels (friends and neighbors), radio, local metropolitan daily newspapers, and ethnic-language newspapers. Size of ethnic group is linked to channel preference, and greater ethnicity is related to a preference for ethnic media for both functions. Lower SES ethnics lend to rely more on interpersonal communication and ethnic media, while higher SES ethnics turn more to metro media and magazines. Channel preference as indicated by respondents is also linked to actual usage patterns.