Hydrodynamic self-focusing in a parallel microfluidic device through cross-filtration

The flow focusing is a fundamental prior step in order to sort, analyze, and detect particles or cells. The standard hydrodynamic approach requires two fluids to be injected into the microfluidic device: one containing the sample and the other one, called the sheath fluid, allows squeezing the sample fluid into a narrow stream. The major drawback of this approach is the high complexity of the layout for microfluidic devices when parallel streams are required. In this work, we present a novel parallelized microfluidic device that enables hydrodynamic focusing in each microchannel using a single feed flow. At each of the parallel channels, a cross-filter region is present that allows removing fluid from the sample fluid. This fluid is used to create local sheath fluids that hydrodynamically pinch the sample fluid. The great advantage of the proposed device is that, since only one inlet is needed, multiple parallel micro-channels can be easily introduced into the design. In the paper, the design method is described and the numerical simulations performed to define the optimal design are summarized. Moreover, the operational functionality of devices tested by using both polystyrene beads and Acute Lymphoid Leukemia cells are shown.     

Core-shell hydrogel beads with extracellular matrix for tumor spheroid formation

Creating multicellular tumor spheroids is critical for characterizing anticancer treatments since they may provide a better model of the tumor than conventional monolayer culture. Moreover, tumor cell interaction with the extracellular matrix can determine cell organization and behavior. In this work, a microfluidic system was used to form cell-laden core-shell beads which incorporate elements of the extracellular matrix and support the formation of multicellular spheroids. The bead core (comprising a mixture of alginate, collagen, and reconstituted basement membrane, with gelation by temperature control) and shell (comprising alginate hydrogel, with gelation by ionic crosslinking) were simultaneously formed through flow focusing using a cooled flow path into the microfluidic chip. During droplet gelation, the alginate acts as a fast-gelling shell which aids in preventing droplet coalescence and in maintaining spherical droplet geometry during the slower gelation of the collagen and reconstituted basement membrane components as the beads warm up. After droplet gelation, the encapsulated MCF-7 cells proliferated to form uniform spheroids when the beads contained all three components: alginate, collagen, and reconstituted basement membrane. The dose-dependent response of the MCF-7 cell tumor spheroids to two anticancer drugs, docetaxel and tamoxifen, was compared to conventional monolayer culture.     

Flipping the classroom to teach systematic reviews: the development of a continuing education course for librarians

Objective:The researchers used the flipped classroom model to develop and conduct a systematic review course for librarians.Setting:The research took place at an academic health sciences library.Method:A team of informationists developed and conducted a pilot course. Assessment informed changes to both course components; a second course addressed gaps in the pilot.Conclusion:The flipped classroom model can be successful in developing and implementing a course that is well rated by students.     

#MeToo,sexual harassment: an article,a forum,and a dream for the future

#MeToo has breathed new life into the women’s movement and especially into understanding and rectifying sexual harassment, abuse and assault. It has galvanized activists around the globe. And it has placed thousands of stories of the harassed in full view of the public. Sexual harassment, abuse and assault may occur within the organizational context or beyond; but sexual harassment, in particular has been legally labeled an organizational phenomenon. With this in mind, Robin Clair frames the early part of this article around the most recent organizational communication theories (see the appendix for an overview of these theories). Following the essay is a forum, in which invited scholars address questions related to the #MeToo movement.     

A Phenomenon We Can't Ignore: Performance Improvement Interventions to Address Workplace Bullying

Workplace bullying is a significant problem impacting both individual performance and performance of organizations as a whole. This article describes how a systematic approach was utilized by focusing on the organizational subsystem of human resources as it relates to preventing, identifying, and addressing workplace bullying. Human resource (HR) professionals play a vital role in applying anti‐bullying policies and performance improvement interventions. The article outlines the interventions and policies utilized by HR professionals to alleviate and manage bullying that have been cited in the literature.     

Infants’ and Young Children's Imitation of Linguistic In‐Group and Out‐Group Informants

Although children can use social categories to intelligently select informants, children's preference for in‐group informants has not been consistently demonstrated across age and context. This research clarifies the extent to which children use social categories to guide learning by presenting participants with a live or video‐recorded action demonstration by a linguistic in‐group and/or out‐group model. Participants’ (N = 104) propensity to imitate these actions was assessed. Nineteen‐month‐olds did not selectively imitate the actions of the in‐group model in live contexts, though in‐group preferences were found after watching the demonstration on video. Three‐year‐olds selectively imitated the actions demonstrated by the in‐group member regardless of context. These results indicate that in‐group preferences have a more nuanced effect on social learning than previous research has indicated.