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  1. Self-healing soft electronic and robotic devices can, like human skin, recover autonomously from damage. While current devices use a single type of dynamic polymer for all functional layers to ensure strong interlayer adhesion, this approach requires manual layer alignment. In this study, we used two dynamic polymers, which have immiscible backbones but identical dynamic bonds, to maintain interlayer adhesion while enabling autonomous realignment during healing. These dynamic polymers exhibit a weakly interpenetrating and adhesive interface, whose width is tunable. When multilayered polymer films are misaligned after damage, these structures autonomously realign during healing to minimize interfacial free energy. We fabricated devices with conductive, dielectric, and magnetic particles that functionally heal after damage, enabling thin-film pressure sensors, magnetically assembled soft robots, and underwater circuit assembly.

     
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    Free, publicly-accessible full text available June 2, 2024
  2. Abstract

    Pelagic photosynthesis and respiration serve critical roles in controlling the dissolved oxygen (DO) concentration in seawater. The consumption and production via pelagic primary production are of particular importance in the surface ocean and in freshwater ecosystems where photosynthetically active radiation is abundant. However, the dynamic nature and large degree of heterogeneity in these ecosystems pose substantial challenges for providing accurate estimates of marine primary production and metabolic state. The resulting lack of higher‐resolution data in these systems hinders efforts in scaling and including primary production in predictive models. To bridge the gap, we developed and validated a novel automated water incubator that measures in situ rates of photosynthesis and respiration. The automated water incubation system uses commercially available optodes and microcontrollers to record continuous measurements of DO within a closed chamber at desired intervals. With fast response optodes, the incubation system produced measurements of photosynthesis and respiration with an hourly resolution, resolving diel signals in the water column. The high temporal resolution of the time series also enabled the development of Monte Carlo simulation as a new data analysis technique to calculate DO fluxes, with improved performance in noisy time series. Deployment of the incubator was conducted near Ucantena Island, Massachusetts, U.S.A. The data captured diel fluctuations in metabolic fluxes with an hourly resolution, allowed for a more accurate correlation between oxygen cycling and environmental conditions, and provided improved characterization of the pelagic metabolic state.

     
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  3. Abstract

    Although eusocial animals often achieve ecological dominance in the ecosystems where they occur, many populations are unstable, resulting in local extinction. Both patterns may be linked to the characteristic demography of eusocial species—high reproductive skew and reproductive division of labor support stable effective population sizes that make eusocial groups more competitive in some species, but also lower effective population sizes that increase susceptibility to population collapse in others. Here, we examine the relationship between demography and social organization in Synalpheus snapping shrimps, a group in which eusociality has evolved recently and repeatedly. We show using coalescent demographic modeling that eusocial species have had lower but more stable effective population sizes across 100,000 generations. Our results are consistent with the idea that stable population sizes may enable competitive dominance in eusocial shrimps, but they also suggest that recent population declines are likely caused by eusocial shrimps’ heightened sensitivity to environmental changes, perhaps as a result of their low effective population sizes and localized dispersal. Thus, although the unique life histories and demography of eusocial shrimps have likely contributed to their persistence and ecological dominance over evolutionary time scales, these social traits may also make them vulnerable to contemporary environmental change.

     
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  4. The construction industry still leads the world as one of the sectors with the most work-related injuries and worker fatalities. Recent studies show that both a state of mindfulness and various personality traits contribute to individuals’ safety and work performance. This study examines the relationship between mindfulness and personality by measuring the mindfulness state of individuals against their personality traits. To achieve this objective, data were collected from a sample of 55 undergraduate students at George Mason University. Scores from the Big Five Inventory were ranked by each traits’ score (independent variable) and split into three groups: high, moderate, and low scores. The corresponding mindfulness scores (dependent variable) were analyzed to determine the relationship between high/low personality traits and mindfulness. Comparing the high/low groups using statistical analyses showed that three of the five personality traits—conscientiousness, agreeableness, and neuroticism—significantly correlate with higher mindfulness scores of individuals. As mindfulness has been shown to increase individual safety and work performance and to reduce stress, the results of this study help inform future work into translating personality and mindfulness characteristics into factors that predict specific elements of unsafe human behaviors. 
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  5. Abstract

    Across plants and animals, genome size is often correlated with life‐history traits: large genomes are correlated with larger seeds, slower development, larger body size and slower cell division. Among decapod crustaceans, caridean shrimps are among the most variable both in terms of genome size variation and life‐history characteristics such as larval development mode and egg size, but the extent to which these traits are associated in a phylogenetic context is largely unknown. In this study, we examine correlations among egg size, larval development and genome size in two different genera of snapping shrimp,AlpheusandSynalpheus, using phylogenetically informed analyses. In bothAlpheusandSynalpheus, egg size is strongly linked to larval development mode: species with abbreviated development had significantly larger eggs than species with extended larval development. We produced the first comprehensive dataset of genome size inAlpheus(n = 37 species) and demonstrated that genome size was strongly and positively correlated with egg size in bothAlpheusandSynalpheus. Correlated trait evolution analyses showed that inAlpheus, changes in genome size were clearly dependent on egg size. InSynalpheus, evolutionary path analyses suggest that changes in development mode (from extended to abbreviated) drove increases in egg volume; larger eggs, in turn, resulted in larger genomes. These data suggest that variation in reproductive traits may underpin the high degree of variation in genome size seen in a wide variety of caridean shrimp groups more generally.

     
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  6. Abstract

    Transposable elements (TEs) – selfish DNA sequences that can move within the genome – comprise a large proportion of the genomes of many organisms. Although low‐coverage whole‐genome sequencing can be used to survey TE composition, it is noneconomical for species with large quantities of DNA. Here, we utilize restriction‐site associated DNA sequencing (RADSeq) as an alternative method to survey TE composition. First, we demonstrate in silico that double digest restriction‐site associated DNA sequencing (ddRADseq) markers contain the same TE compositions as whole genome assemblies across arthropods. Next, we show empirically using eightSynalpheussnapping shrimp species with large genomes that TE compositions from ddRADseq and low‐coverage whole‐genome sequencing are comparable within and across species. Finally, we develop a new bioinformatic pipeline, TERAD, to extract TE compositions from RADseq data. Our study expands the utility of RADseq to study the repeatome, making comparative studies of genome structure for species with large genomes more tractable and affordable.

     
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  7. Abstract

    The solid electrolyte interphase (SEI) has been identified as a key challenge for Li metal anodes. The brittle and inhomogeneous native SEI generated by parasitic reactions between Li and liquid electrolytes can devastate battery performance; therefore, artificial SEIs (ASEIs) have been proposed as an effective strategy to replace native SEIs. Herein, as a collaboration between academia and industrial R&D teams, a multifunctional (crystalline, high modulus, and robust, Li+ion conductive, electrolyte‐blocking, and solution processable) ASEI material, LiAl‐FBD (where “FBD” refers to 2,2,3,3‐tetrafluoro‐1,4‐butanediol), for improving Li metal battery performance is designed and synthesized. The LiAl‐FBD crystal structure consists of Al3+ions bridged by FBD2–ligands to form anion clusters while Li+ions are loosely bound at the periphery, enabling an Li+ion conductivity of 9.4 × 10–6S cm–1. The fluorinated, short ligands endow LiAl‐FBD with electrolyte phobicity and high modulus. The ASEI is found to prevent side reactions and extend the cycle life of Li metal electrodes. Specifically, pairing LiAl‐FBD coated 50 µm thick Li with industrial 3.5 mAh cm–2NMC811 cathode and 2.8 µL mAh–1lean electrolyte, the Li metal full cells show superior cycle life compared to bare ones, achieving 250 cycles at 1 mA cm–2.

     
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  8. Abstract

    The practical implementation of Li metal batteries is hindered by difficulties in controlling the Li metal plating microstructure. While previous atomic layer deposition (ALD) studies have focused on directly coating Li metal with thin films for the passivation of the electrode–electrolyte interface, a different approach is adopted, situating the ALD film beneath Li metal and directly on the copper current collector. A mechanistic explanation for this simple strategy of controlling the Li metal plating microstructure using TiO2grown on copper foil by ALD is presented. In contrast to previous studies where ALD‐grown layers act as artificial interphases, this TiO2layer resides at the copper–Li metal interface, acting as a nucleation layer to improve the Li metal plating morphology. Upon lithiation of TiO2, a LixTiO2complex forms; this alloy provides a lithiophilic surface layer that enables uniform and reversible Li plating. The reversibility of lithium deposition is evident from the champion cell (5 nm TiO2), which displays an average Coulombic efficiency (CE) of 96% after 150 cycles at a moderate current density of 1 mA cm−2. This simple approach provides the first account of the mechanism of ALD‐derived Li nucleation control and suggests new possibilities for future ALD‐synthesized nucleation layers.

     
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