化学•材料最新文献

Effective sludge dewatering is essential for reducingsludge volumeand associated transportation and disposal burdens. However, conventionalapproaches often require substantial chemical addition or energy input,increasing operating costs and potential secondary environmental impacts.Here, we present a CO₂ hydrate crystallization-based dewateringapproach that avoids conventional chemical sludge conditioners. Residualwater in mechanically dewatered sludge is converted into separablesolid hydrate structures, with water molecules incorporated into hydrogen-bondedhydrate cages and sludge-derived solutes and particulates excludedfrom the hydrate lattice. Low-field nuclear magnetic resonance measurementsshowed that hydrate crystallization promoted the mobilization of mechanicallybound water, whose relative signal fraction decreased from 68.2% to40.7%. With methionine as a kinetic promoter, repeated hydrate formationand separation reduced the sludge water content to 59.3%. The screening-levelprocess electricity demand was estimated at 0.247–0.298 kWh/kgof removed water, depending on the cold energy recovery scenario.The process also retained most sludge-derived volatile solids andproduced hydrate-dissociated water with reduced aqueous constituentlevels following hydrate layer separation. These results highlightCO₂ hydrate crystallization as a phase-transition-drivenstrategy for deep sludge dewatering, with energy integration and solid–liquidseparation remaining key considerations for further process development.

We developed a bottom-up, data-driven approach for constructinga time-informed adverse outcome pathway (AOP) network for environmentalchemical-induced cardiotoxicity. Mechanistic end points were systematicallyextracted from 339 in vitro and in vivo studies, yielding 1759 KeyEvent (KE) entries and 4938 Key Event Relationship (KER) entries,together with study metadata and essentiality evidence from interventionexperiments. After quality filtering and minimum support thresholding,62 unique KEs and 256 unique KERs were retained for network construction.Network analysis highlighted oxidative stress and mitochondrial dysfunctionas prominent, highly connected KEs linking diverse upstream perturbationsto downstream cardiomyocyte injury, inflammation, cardiac remodeling(fibrosis and hypertrophy), decreased myocardial contractility, andreduced left ventricular function. A central methodological findingwas that temporal information was more informative at the level ofKERs than at the level of KEs. The same KE could occur across multipledurations depending on the relationship in which it was embedded,whereas KER-level time-scale annotation resolved distinct acute, subacute,and chronic pathway patterns not apparent from KE timing alone. Thisframework provides an evidence-weighted synthesis of the most consistentlysupported cardiotoxicity mechanisms and introduces a temporal layerfor the mechanistic interpretation of heterogeneous evidence.

Heterogeneous electro-Fenton (HEF) systems hold greatpotentialfor decentralized water purification, yet concurrently achieving highcatalytic activity, structural stability, and controlled reactiveoxygen species (ROS) selectivity remains challenging. Herein, we proposea spatiotemporal magnetic decoupling strategy to concurrently addressthese design objectives. The carbon shell spatially separated exteriorFe⁰ satellites from the FeN_x core, eliminating deleterious short-range magnetic quenching andaltering the local magnetic environment to modulate the internal Fe(III)spin state. The resulting low-spin Fe(III) sites suppressed electronback-donation into the H₂O₂ σ∗antibonding orbital, favoring an additional ¹O₂ generation pathway. Spatial decoupling also enabled a gradient cascadeactivation of H₂O₂ across the Fe⁰ and FeN_x domains, synergistically boostingthe evolution of both ^•OH and ¹O₂, with steady-state concentrations reaching 18.25 and 5.27μM, respectively. Consequently, the FeN_x@C–Fe⁰-based HEF achieved complete naproxendegradation within 60 min with significantly suppressed Fe leaching(0.85 mg L^–1), outperforming all comparative systems.Comprehensive characterizations and density functional theory (DFT)calculations established a definitive relationship between topologicalengineering and spin-state dynamics. Furthermore, the system demonstratedproof-of-concept applicability in real hospital wastewater, highlightingthe potential of spatiotemporal spin-state engineering for regulatingROS evolution in HEF systems.

Vehicular emissions are an important source of urbanair pollutionthat can age through atmospheric processes, but how their health effectschange during atmospheric aging remains poorly understood. To simulaterealistic urban emissions, we sampled air in a parking garage wherecold-start and urban emissions coexist. Following aging in an oxidationflow reactor (OFR), we studied the cellular and acellular effectsof the fresh and aged aerosols. Photochemical aging in the OFR increasedsecondary organic aerosol (SOA) mass by up to 6.9-fold, the oxygen-to-carbon(O:C) ratio from 0.26 to 0.79, and both the intrinsic oxidative potential(OPm) and the volume-normalized oxidative potential (OPv). In contrast,the peroxide-sensitive DCF activity decreased following aging. Cellularexposure to aged aerosol extracts increased cellular reactive oxygenspecies (ROS) formation in lung (A549) and liver (HepG2) cells, whereasfresh extracts strongly reduced cellular respiration, particularlyin HepG2 cells. Cell painting analysis showed distinct morphologicalprofiles. Exposure to aged extracts showed greater oxidative stressand DNA damage responses than those of exposure to fresh extracts.These findings suggest that atmospheric aging shifts the toxicityof fresh emissions from suppression of mitochondrial respiration towardoxygenated organics that can drive intracellular oxidative stressand DNA damage phenotypes. In conclusion, atmospheric aging of cold-startand urban vehicular emissions contributes to enhanced SOA formationand leads to distinct biological outcomes that depend on the degreeof oxidative aging.

In recent years, freshwater harmful cyanobacterial blooms(CyanoHABs)and their associated cyanotoxins have been increasingly detected inestuaries and coastal lagoons, indicating that some freshwater taxacan survive in low-to-moderate salinity and may maintain their toxigenicpotential in brackish environments. These observations highlight theneed to understand the distribution, persistence, and ecological risksof freshwater harmful cyanobacteria across connected aquatic systems.This review synthesizes global field and mechanistic evidence on theexpansion of freshwater harmful cyanobacteria along the freshwater–to–marinecontinuum. Hydrodynamic processes facilitate downstream transport,while salinity gradients regulate cyanobacterial survival and physiologicalresponses. Salt stress induces cellular damage but also triggers adaptivephysiological responses supporting survival. The persistence of freshwaterharmful cyanobacteria in these systems is shaped by both species-and strain-level differences in salt tolerance, as well as physiologicalconditioning and environmental conditions experienced during transport.In addition, salinity influences cyanotoxin production, release, partitioningbetween particulate and dissolved fractions, and environmental persistence,thereby influencing ecological risks in brackish waters. Overall,this review synthesizes cyanobacterial adaptation and cyanotoxin dynamicsalong the freshwater–to–marine continuum and emphasizesintegrated monitoring and modeling to support risk assessment andmanagement of CyanoHABs.

Natural hazards affect the environmental sustainabilityof thebuilt environment because of the environmental losses caused, suchas the environmental impacts of the repairs and the indirect effectsof downtime. Asset performance assessment workflows allow for probabilisticallyconnecting frequent and infrequent hazards with building response,damages, and environmental losses. Environmental life cycle assessmentis emerging as the preferred methodology to derive environmental losses,but current tools struggle with interoperability issues, promptingsimplifications in converting the material damages to environmentallosses and limiting environmental uncertainty propagation. This studyproposes a novel coupling framework that leverages a dual presamplingstrategy paired with a preaggregation step on background environmentaldatasets, expediting in minutes the computation of thousands of stochasticenvironmental life cycle assessment results. The coupling frameworkis demonstrated with two scales of asset performance assessment workflows:one for individual buildings and one for portfolios of buildings,both exposed to a hurricane hazard. The case studies underline keyloss drivers originating from different steps in the workflow, includingthe conversion from damages to environmental losses. The couplingframework provides groundwork for identifying natural hazard effectson the sustainability of the built environment, a key step in formulatingsustainable adaptation strategies to a changing climate.

Molecules that formirreversible covalent bonds with their targetsare a mainstay of drug discovery and chemical biology research. Theirability to permanently inactivate an enzyme target provides a mechanismwith significant potential to modulate disease phenotypes. This perspectivediscusses the trajectory of the field of irreversible enzyme inhibitorswith an outlook on emerging methods, warhead structures, and sentimentspresently directing practices in the discovery and design of the nextwave of covalent agents.

Long-range proteinelectron transfer (ET) often depends on tryptophanand tyrosine residues acting as radical relay sites. For example,cytochrome c peroxidase (CcP) generates a W191^•+ radical to increase ET from cytochrome c (Cc) tothe active center. W191 substitution to Tyr reduces ET rates, butintroduction of an adjacent general base (as Glu or His) at position232 (Y191:E/H232 CcP) recovers activity. E232 fluorination lowersthe pK_a of the conjugate base and confirmsthat a hydrogen bond is critical to elevate the Y191^• formal potential for effective ET. Photoinitiated ET between Zn-porphyrin(ZnP) CcP (ZnCcP) and Cc also depends on activatingY191 with a basic residue but through a different mechanism than forthe peroxide-driven system. In ZnCcP, pH dependencies and solventisotope effects indicate that proton-coupled electron transfer tothe basic residue and ZnP^•+, respectively, facilitatesY191^• formation. Replacing Cc withthe irreversible oxidant [Co(NH3)₅Cl]²⁺ isolatesdistinct protein radicals for characterization by electron paramagneticresonance (EPR) spectroscopy. Radical distributions and computationindicate that W191^•+ lies close in potential toZnP^•+ and that the two radicals exchange on a slowtime scale despite their close separation. Remarkably, Y191:E/H232ZnCcP variants propagate radicals differently to peripheral sitesdepending on the nature of the 232 residue. QM/MM calculations supportradical exchange between ZnP^•+/Trp^•+ and the importance of a hydrogen bond to Y191^• for maintaining a high potential to oxidize peripheral donors. Theseresolved reactivity patterns of CcP/ZnCcP have general relevance forengineering proton management to separate and migrate charge in proteinsand potentially other molecular systems.