Rekindling the use of acetylene as a chemical building block
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Controlled layer-by-layer assembly and structured coloration of Ti3C2Tz MXene/polyelectrolyte heterostructures
Structural color arises from light scattering rather than organic pigments and can be found in Nature, such as in bird feathers and butterfly wings. Synthetic materials can mimic Nature by leveraging materials with contrasting optical characteristics by controlling each materials’ spatial arrangement in a heterostructure. Two-dimensional MXene nanosheets are particularly interesting due to their unique optical properties, but MXenes have not been used directly as a structural colorant because it is challenging to control the spatial placement of MXenes at the nanometer level. Here, we report the emergence of structural color in layer-by-layer (LbL) assemblies of Ti3C2Tz MXene nanosheets and polyelectrolyte heterostructures with controlled block thicknesses. The block thickness and spatial placement of MXene are controlled by the assembly’s salt concentration and number of layer pairs. This work demonstrates that optical characteristics of MXene/polyelectrolyte heterostructures depend on MXene content and placement, while deepening the understanding of MXenes within structural color films.
Water and wastewater infrastructure inequity in unincorporated communities
Uneven access to water and wastewater infrastructure is shaped by local governance. A substantial number of U.S. households lack adequate access and the U.S. is one of the few countries with large populations living outside of city bounds, in unincorporated areas. Few studies address how infrastructure services and local governance are intertwined at a regional scale. We examine the connection between incorporation status and access to centralized infrastructure, using negative binomial regression. A novel dataset informs this analysis, comprised of 31,383 Census block groups located in nine states representing over 25% of the national population. We find evidence that inequities in access are associated with unincorporated status and poverty rates. Sewer coverage rates are significantly lower for unincorporated communities in close proximity to municipal boundaries. Infrastructure equity could be improved by targeting high-poverty unincorporated communities, addressing challenges with noncontiguous service areas, and strengthening regional water planning and participatory governance.
Nanomolar inhibitor of the galectin-8 N-terminal domain binds via a non-canonical cation-π interaction
Galectin-8 is a tandem-repeat galectin consisting of two distinct carbohydrate recognition domains and is a potential drug target. We have developed a library of galectin-8N inhibitors that exhibit high nanomolar Kd values as determined by a competitive fluorescence polarization assay. A detailed thermodynamic analysis of the binding of d-galactosides to galectin-8N by isothermal titration calorimetry reveals important differences in enthalpic and/or entropic contributions to binding. Contrary to expectations, the binding of 2-O-propargyl-d-galactoside was found to strongly increase the binding enthalpy, whereas the binding of 2-O-carboxymethylene-d-galactoside was surprisingly less enthalpy-driven. The results of our work suggest that the ethynyl group can successfully replace the carboxylate group when targeting the water-exposed guanidine moiety of a critical arginine residue. This results in only a minor loss of affinity and an adjusted enthalpic contribution to the overall binding due to non-canonical cation-π interactions, as evidenced by the obtained crystal structure of 2-O-propargyl-d-galactoside in complex with the N-terminal domain of galectin-8. Such an interaction has neither been identified nor discussed to date in a small-molecule ligand-protein complex.
The challenge of monitoring policy mixes for reducing emissions from buildings
The building sector accounts for about 34% of global energy use and correspondingly 37% of global greenhouse gas emissions. Even leading regions and countries struggle to address these emissions. Well-crafted mixes of public policy initiatives are crucial to progress, but what systems are in place to track existing policy initiatives and their effectiveness? To address this question, we focus on the UN, the EU, Finland and Germany, where existing tracking systems have received little attention from a comparative perspective so far. Utilising desirable dimensions of monitoring and reporting of policy mixes from existing literature, we find that the monitoring systems in focus have become more streamlined and coordinated over time. But policy interactions have not yet been sufficiently considered and different baselines hamper comparability. Such factors hinder policy-makers to understand and adjust the complex policy mix in the buildings sector to deliver effective climate action. Core discipline: Political science/policy sciences.
D5 digital circular workflow: five digital steps towards matchmaking for material reuse in construction
The intersection of digital transformation and circular construction practices presents significant potential to mitigate environmental impacts through optimised material reuse. We propose a five-step (D5) digital circular workflow that integrates these digital innovations towards reuse, validated through real-world case studies. We assessed a variety of digital tools for enhancing the reuse of construction materials, including digital product passports, material classification assisted by artificial intelligence (AI), reality capture, computational design, design inspired by generative AI, digital fabrication techniques, extended reality, and blockchain technology. Using action research through a multiple case study approach, we disassembled several buildings that were set for demolition and subsequently designed and executed construction projects using the salvaged materials. Our findings indicate that digital transformation for detection, disassembly, distribution, design, and finally deployment significantly support the application of circular economy principles. We demonstrate the potential of the proposed workflow for industry implementation and scalability.
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