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Introduction:Two-component response systems (TCRS) are the main mechanism by which prokaryotes acclimate to changing environments. These systems are composed of a membrane bound histidine kinase (HK) that senses external signals and a response regulator (RR) that activates transcription of response genes. Despite their known role in acclimation, little is known about the role TCRS play in environmental adaptation. Several experimental evolution studies have shown the acquisition of mutations in TCRS during adaptation, therefore here we set out to characterize the adaptive mechanism resulting from these mutations and evaluate whether single nucleotide changes in one gene could induce variable genotype-by-environment (GxE) interactions. Methods:To do this, we assessed fitness changes and differential gene expression for four adaptive mutations incusS, the gene that encodes the HK CusS,acquired byEscherichia coliduring silver adaptation. Results:Fitness assays showed that as the environment changed, each mutant displayed a unique fitness profile with greatest fitness in the original selection environment. RNAseq then indicated that, in ± silver nitrate, each mutant induces a primary response that upregulatescusS,its RRcusR, and constitutively expresses the target response genescusCFBA. This then induces a secondary response via differential expression of genes regulated by the CusR through TCRS crosstalk. Finally, each mutant undergoes fitness tuning through unique tertiary responses that result in gene expression patterns specific for the genotype, the environment and optimized for the original selection conditions. Discussion:This three-step response shows that different mutations in a single gene leads to individualized phenotypes governed by unique GxE interactions that not only contribute to transcriptional divergence but also to phenotypic plasticity. 

We conducted a 2x2 Wizard of Oz between-subject user study with sixteen healthy older adults. We investigated how to make social robots converse more naturally and reciprocally through unstructured conversation. We varied the level of interaction by changing the level of verbal and nonverbal communication the robot provided. Participants interacted with the robot for eight sessions engaging in an unstructured conversation. These conversations lasted thirty minutes to an hour. This paper will evaluate four questions from the post-interaction survey individuals completed after each session with the robot. The questions include: (i) I had fun talking to the robot; (ii) I felt I had a meaningful conversation; (iii) I was engaged the whole interaction; and (iv) I would consider the robot my friend. All participants reported they were engaged, had a meaningful conversation, and had fun during all eight sessions. Seven individuals felt the robot was their friend. 

COVID-19 is exacerbating isolation issues faced by older adults, which may lead to increased risk for depression and other mental health issues. Social robots are being explored for their potential to alleviate these challenges through conversational therapy, companionship, and connectedness regardless of where older adults chose to age in place—from home to long-term care facilities. This is a discussion piece with the objective of raising awareness to the topic of social isolation within older adults and current limitations in the field of social robotics. We discuss the state of the art in social robotics for aging in place and bring attention to remaining challenges for addressing isolation and mental health especially during and after COVID-19. This paper provides a discussion on critical differences between environments where older individuals age, and how designs should account for these variations. Lastly, this paper highlights the physical and mental health issues of caregivers and provides a discussion of challenges that remain toward using social robotics to assist those who take care of the aging population. 

This paper highlights current technological limitations and offers recommendations for scientists and engineers when designing devices to support aging in place. Existing technology for older adults to support independent living is examined as well as the implications of contextual factors, namely, location, on how people live and age based on the location in which they reside. This is the first review to investigate how challenges of aging change relative to location of residence and, subsequently, how such variation may inform technological solutions. To date, few devices consider the environment in which older individuals age. Places examined include aging: at home; assisted living facilities; nursing homes; and family housing. Challenges found in common across these locations were financial strain and isolation. In addition, each setting was found to have its own unique hurdles. Understanding these barriers is essential to developing technology that enables older adults to successfully age in place. 

Solid organs transport fluids through distinct vascular networks that are biophysically and biochemically entangled, creating complex three-dimensional (3D) transport regimes that have remained difficult to produce and study. We establish intravascular and multivascular design freedoms with photopolymerizable hydrogels by using food dye additives as biocompatible yet potent photoabsorbers for projection stereolithography. We demonstrate monolithic transparent hydrogels, produced in minutes, comprising efficient intravascular 3D fluid mixers and functional bicuspid valves. We further elaborate entangled vascular networks from space-filling mathematical topologies and explore the oxygenation and flow of human red blood cells during tidal ventilation and distension of a proximate airway. In addition, we deploy structured biodegradable hydrogel carriers in a rodent model of chronic liver injury to highlight the potential translational utility of this materials innovation.