Oregon Center For Applied Science (United States)

Bipolar membranes (BPMs) create counteracting pH and electrostatic-potential gradients in electrochemical systems which make them of utility for pH regulation, electrocatalysis, and separations. At the polarized, interfacial junctions of a BPM, the water dissociation (WD, 2H2O ⇌ H3O⁺ + OH⁻) reaction can be driven, but it remains poorly understood. In this Perspective, we integrate molecular insights from bulk-water autoionization and field effects with continuum descriptions of BPM electrostatics and recent WD kinetics analyses. Pristine BPM junctions highlight both the limits of field-only acceleration and the practical challenges of junction stability at extreme reverse bias. Introducing heterogeneous catalyst layers, most commonly metal oxides and graphene oxides, accelerate WD by orders of magnitude through hypothesized coupled effects: i) surface acidbase functionality and hydroxyl-site density mediate proton-transfer steps, and ii) catalyst electronic/ionic polarizability redistributes the junction potential drop, shaping local electric fields and reactive microenvironments. Kinetic analyses suggest two regimes of heterogeneous WD mechanism, including fielddriven ordering of interfacial water and a Second Wien-type dissociation barrier lowering. We conclude by defining the key unknown variables (local pH, electrostatic potential, catalyst charge state and connection between mechanisms) and outlining experimental and multiscale modeling strategies needed for predictive WD catalysis and related ion-transfer reactions.

Commercial membrane electrolyzers rely on acidic fluorocarbon membranes and ionomers, requiring the use of expensive IrOx-based oxygen-evolution catalysts. Anion-exchange-membrane water electrolyzers (AEMWEs) operate in an alkaline environment, enabling the use of non-precious-metal catalysts. Here, we study and engineer CoOx-based catalyst-coated anodes deposited via hydrothermal synthesis directly onto porous transport layers both with and without thermal annealing. The self-supported, nanoneedle-structured Co3O4 anode, formed by annealing the as-synthesized cobalt carbonate hydroxide, Co(CO3)x(OH)y, outperforms the baseline Co3O4 nanoparticle ink-based anode in pure-water-fed AEMWE due to the improved catalyst-layer continuity and thus number of electroactive Co species. The as-synthesized and unannealed Co(CO3)x(OH)y, however, appears to undergo substantial conversion to a more-active CoOx(OH)y phase predominantly at the surface, with nominal Co3+ present and higher electrical conductivity, lowering the cell voltage to ∼200 mV at 1.0 A·cm–2 in pure-water-fed AEMWE compared to the conventional Co3O4 nanoparticle anodes. We analyze the differences in electrode electrochemical response between pure-water and KOH feed modes, finding distinct activation and degradation modes. The Co(CO3)x(OH)y anode shows significant activation and slower degradation linked to the conversion to oxyhydroxide. We propose catalyst layer designs that promote both hydroxide and electron transport, alongside interfacial engineering strategies to obtain high performance while mitigating anode degradation.

Melt electrowriting (MEW) is an emerging high-resolution 3D printing technology used in biomedical engineering, regenerative medicine, and soft robotics. Its transition from academia to industry faces challenges such as slow experimentation, low printing throughput, poor reproducibility, and user-dependent operation, largely due to the nonlinear and multiparametric nature of the MEW process. To address these challenges, we applied computer vision and machine learning to monitor and analyze the process in real-time through imaging of the MEW jet between the nozzle-collector gap. To collect data for training we developed an automated data collection methodology that eases the experimental time from days to hours. A feedforward neural network, working in concert with optimization methods and a feedback loop, is used to develop closed-loop control ensuring reproducibility of the printed parts. We demonstrate that machine learning allows streamlining the MEW operation via closed-loop control of the highly nonlinear 3D printing technology.

There have been calls recently to integrate social justice issues with computing and to teach computing as a non-neutral discipline. Among many critical perspectives considered, colonialism and its manifestation in computing is emerging lately. While we barely know about its implications for secondary computing education, high school teachers' engagement with this issue is yet to be examined. In this paper, we qualitatively analyzed the participation of 12 high school computing teachers in the U.S. in curricular co-design sessions to understand: How did teachers relate to the theme of colonialism? And, what connections did they see to secondary computing teaching? We saw that teachers, though not fluent with the theme initially, quickly related to it through their racial and ethnic backgrounds and U.S. colonial history. They further proposed pedagogical strategies to support student learning within classrooms. Based on these findings, we discuss the need to investigate these connections and their implications for design, research, and practices within K-12 computing education globally.

During C. elegans oocyte meiosis I, cortical actomyosin is locally remodeled to assemble a contractile ring near the spindle. In contrast to mitosis, when most cortical actomyosin converges into a contractile ring, the small oocyte ring forms within and remains part of a much larger and actively contractile cortical actomyosin network. This network both mediates contractile ring dynamics and generates shallow ingressions throughout the oocyte cortex during polar body extrusion. Based on our analysis of requirements for CLS-2, a member of the CLASP family of proteins that stabilize microtubules, we recently proposed that a balance of actomyosin-mediated tension and microtubule-mediated stiffness are required for contractile ring assembly within the oocyte cortical actomyosin network. Here, using live cell imaging and fluorescent protein fusions, we show that CLS-2 is part of a complex of kinetochore proteins, including the scaffold KNL-1 and the kinase BUB-1, that also co-localize to patches distributed throughout the oocyte cortex during meiosis I. By reducing their function, we further show that KNL-1 and BUB-1, like CLS-2, are required for cortical microtubule stability, to limit membrane ingression throughout the oocyte, and for meiotic contractile ring assembly and polar body extrusion. Moreover, nocodazole or taxol treatment to destabilize or stabilize oocyte microtubules, respectively, leads to excess or decreased membrane ingression throughout the oocyte and defective polar body extrusion. Finally, genetic backgrounds that elevate cortical microtubule levels suppress the excess membrane ingression in cls-2 mutant oocytes. These results support our hypothesis that CLS-2, as part of a sub-complex of kinetochore proteins that also co-localize to patches throughout the oocyte cortex, stabilizes microtubules to stiffen the oocyte cortex and limit membrane ingression throughout the oocyte, thereby facilitating contractile ring dynamics and the successful completion of polar body extrusion during meiosis I.

Abstract Professional isolation, a familiar issue in world language education, has been exacerbated by the COVID‐19 pandemic. This article addresses this issue by providing world language educators with practical guidance related to establishing high‐functioning professional networks online. Empirical findings related to computer‐mediated communication (CMC) in language learning and teacher training contexts support the articulation of four critical considerations for successful online professional communities: that participants (a) possess requisite technical knowledge to navigate the platforms being utilized; (b) develop requisite reflective and evaluative competencies; (c) exhibit ongoing, sustained engagement; and (d) engage collaboratively with other participants. In concert, successful treatment of these considerations not only provides practitioners with a temporary solution to engage in physically distant collaboration, but also may help establish a more robust, sustainable professional development infrastructure for world language teachers in the future.

It is impossible to mention key issues such as Reason of State, Sovereignty, Monopoly of Power and enforcement mechanisms in the use of state force without seeking their intellectual origins in Machiavelli.This article seeks to present a description of the political context in which Machiavelli was inserted to better understand their policy recommendations.Moreover, it presents a study of the concepts within the strategy of state in security field in Machiavelli's Art of War.

This research evaluated an individualized Internet training designed to teach nurse aides (NAs) strategies to prevent or, if necessary, react to resident aggression in ways that are safe for the resident as well as the caregiver. A randomized treatment and control design was implemented, with baseline, 1-, and 2-month assessments for 158 NAs. The training involved 2 weekly visits. The Internet intervention was a behaviorally focused and video-based training that included content on skills for safely dealing with physical aggression. Measures included video situation testing and assessment of psychosocial constructs associated with behavior change. Analysis of covariance showed positive results for knowledge, attitudes, self-efficacy, and empathy, with medium-large effect sizes maintained after 2 months. The training was well received by participants. Internet training is a viable approach to shape appropriate NA reactions to aggressive resident behaviors. This format has future potential because it offers fidelity of presentation and automated documentation, with minimal supervision.

Quasispherical resonators are cavity resonators whose acoustic and electromagnetic modes are used in precision measurements, with shapes designed to split the l = 1 triplet modes to facilitate precise determination of the eigenfrequencies. The shapes can be represented in spherical coordinates by $${r=a[1-\varepsilon \fancyscript{F}(\theta,\phi)]}$$ where $${a\ge \max(r),\, \varepsilon \ll 1}$$ is a positive scale parameter, and $${\fancyscript{F}}$$ is a non-negative function. Shape perturbation theory predicts that the fractional differences between the eigenvalues of the radial acoustic modes and the mean eigenvalues of the l = 1 triplet electromagnetic and acoustic modes can be written in the form $${\fancyscript{C} \varepsilon^2+\fancyscript{C}^{\prime}\varepsilon^3+\ldots}$$ , where the coefficients $${\fancyscript{C}}$$ and $${\fancyscript{C}^{\prime}}$$ depend on the multiplet. The coefficients $${\fancyscript{C}}$$ can be calculated analytically for acoustic modes for arbitrary QSR shapes. The third-order coefficient $${\fancyscript{C}^{\prime}}$$ cannot be calculated analytically but has been determined using finite-element methods for some cases. This article shows how the acoustic values of $${\fancyscript{C}}$$ can be determined using the results of coordinate measuring machines.