Robust fluidic connections to freestanding microfluidic hydrogels

Biomimetic scaffolds approaching physiological scale, whose size and large cellular load far exceed the limits of diffusion, require incorporation of a fluidic means to achieve adequate nutrient/metabolite exchange. This need has driven the extension of microfluidic technologies into the area of biomaterials. While construction of perfusable scaffolds is essentially a problem of microfluidic device fabrication, functional implementation of free-standing, thick-tissue constructs depends upon successful integration of external pumping mechanisms through optimized connective assemblies. However, a critical analysis to identify optimal materials/assembly components for hydrogel substrates has received little focus to date. This investigation addresses this issue directly by evaluating the efficacy of a range of adhesive and mechanical fluidic connection methods to gelatin hydrogel constructs based upon both mechanical property analysis and cell compatibility. Results identify a novel bioadhesive, comprised of two enzymatically modified gelatin compounds, for connecting tubing to hydrogel constructs that is both structurally robust and non-cytotoxic. Furthermore, outcomes from this study provide clear evidence that fluidic interconnect success varies with substrate composition (specifically hydrogel versus polydimethylsiloxane), highlighting not only the importance of selecting the appropriately tailored components for fluidic hydrogel systems but also that of encouraging ongoing, targeted exploration of this issue. The optimization of such interconnect systems will ultimately promote exciting scientific and therapeutic developments provided by microfluidic, cell-laden scaffolds.     

#Handsupdontshoot: connective images and ethical witnessing

In the years since Michael Brown’s death, the hashtag #HandsUpDontShoot has been criticized for supposedly misrepresenting forensic evidence as framed by the Department of Justice. However, an expressive pull has kept alive both the hashtag and the sentiment behind it. The images of #HandsUpDontShoot are compelling in that they offer a glimpse into lived experiences that are often dismissed, ignored, or refuted. In this essay, I trace the aesthetic features of the #HandsUpDontShoot images, which foreground shocking juxtapositions between nonviolent protesters and militarized police forces, to the hashtag’s historical analogue: antilynching photography. Antilynching photography often utilized the aesthetic techniques of remediation, recontextualization, and juxtaposition—aesthetic features used prominently in today’s digital and remix cultures. By noting #HandsUpDontShoot’s use of these same techniques, I illuminate the ways in which Twitter’s connective affordances shape the viewer’s encounter with the images to engender ethical witnessing by affectively linking Brown’s death to shared material experiences of racial minorities. Such encounters propel witnesses beyond distanced objectification and toward an embodied reckoning of those experiences.     

The Effects of Parental Behavior on Infants' Neural Processing of Emotion Expressions

Infants become sensitive to emotion expressions early in the 1st year and such sensitivity is likely crucial for social development and adaptation. Social interactions with primary caregivers may play a key role in the development of this complex ability. This study aimed to investigate how variations in parenting behavior affect infants' neural responses to emotional faces. Event‐related potentials (ERPs) to emotional faces were recorded from 40 healthy 7‐month‐old infants (24 males). Parental behavior was assessed and coded using the Emotional Availability Scales during free‐play interaction. Sensitive parenting was associated with increased amplitudes to positive facial expressions on the face‐sensitive ERP component, the negative central. Findings are discussed in relation to the interactive mechanisms influencing how infants neurally encode positive emotions.