Photoelectrochemical water splitting is a promising pathway for renewable solar fuel production. The photoelectrochemical performance strongly depends on the charge separation ability within the space charge layer. In space charge layer, the charge dynamics should be governed by band bending profile consisting with built-in electric field and space charge layer width, yet the precise mechanisms remain unclear. Herein, using Sn doping to regulate band bending profile of Fe2O3 photoanode, we disentangle the effect of space charge layer width and built-in electric field on charge dynamics in photoelectrochemical water splitting by in-situ time-resolved spectroscopies. Space charge layer width determines the onset of photogenerated charge separation, exhibiting a threshold of ~2.4 nm. Above WSCL threshold, the strong built-in electric field in Fe2O3 photoanode effectively empties the occupied electron trap states and blocks the recombination between the back electrons and charged intermediates, thereby facilitating surface hole accumulation for improving water oxidation reaction rate. Photoelectrochemical performance strongly depends on charge separation within space charge layer, but the precise mechanisms remain unclear. Here, the authors disentangle the effect of space charge layer width and built-in electric field on charge dynamics using in-situ time-resolved techniques.
Segmental tracheal reconstruction requires biomimetic substitutes that replicate both the rigid stenting of cartilage rings and the nutritional support of vascularized fascia. However, conventional tissue engineering is hampered by scarce donor chondrocytes and lengthy cell expansion. Here, we show a rapid tracheal reconstruction strategy using three-dimensional printed porous minichannel scaffolds filled with cartilage granules, platelet-rich plasma, and adipose-derived stem cells. Short-term ectopic incubation enables the grafts to acquire native-like mechanical resilience and transmural vascularization within two weeks. Upon orthotopic transplantation to repair segmental tracheal defects in rabbit and porcine models, these bioengineered grafts maintain airway patency and support preclinical animal survival for up to 115 days. Mechanistically, adipose-derived stem cells enhance cartilage granule survival within the hypoxic minichannels by upregulating glycolytic activity in chondrocytes. By eliminating the need for cell isolation and expansion, this approach offers a translatable solution for bioengineered airway repair. There, the authors develop a tracheal reconstruction strategy using 3D-printed minichannels with stem cell–cartilage composites in preclinical models. Bypassing cell expansion, these tough grafts achieve rapid vascularization and repair segmental airway defects.
Palladium plays a three-fold role in modern science and technology: it serves as a key active center in modern catalytic synthetic methods, occurs as unwanted trace contamination that influences new catalysts development and can lead to false-positive reports, and is an emerging environmental pollutant from automotive catalysts. High activity at ppm/ppb loadings and the necessity to analyze sub-micromolar concentrations of samples are common challenges in these applications, making reliable Pd identification essential. Mass spectrometry (MS) can detect Pd-containing ions in complex mixtures, but post-spectral recognition is difficult when minor Pd signals overlap with signals from other components and fine isotope structures are not visible. The present study introduces a machine-learning-based (ML) approach featuring a graph algorithm for the separation of signals from different multicharged ions and deep-learning classifiers for the automatic recognition of Pd ions in mass spectra of multi-component mixtures down to 10–8 mol L–1. It is applied to Pd intermediates in catalytic synthesis, contaminant catalysis and environmental samples. The scalability of the approach enables extension to Ni, Cu, Ag, Cl and Br. With the developed ML/MS workflow, Pd and other important elements could be automatically revealed; thus, routine MS hardware could be transformed into high-performance scanners. Mass spectrometric detection of Pd-containing ions in complex mixtures poses a challenge due to overlapping spectral features. Here, the authors employ a machine-learning-based graph algorithm to distinguish between various multicharged Pd ions, enabling automatic detection in multicomponent samples.
Oxygen-redox pathways offer a potential route beyond the thermodynamic scaling limitations of conventional metal-redox mechanisms, providing an opportunity to develop oxygen evolution catalysts for efficient and durable anion exchange membrane water electrolysis. However, direct O–O coupling through oxygen-redox chemistry remains difficult because the formation of triplet O2 requires spin-compatible oxygen intermediates, whereas spin-mismatched coupling is energetically unfavorable. Here we show that electrochemical reconstruction of V-doped CoS2 produces a cobalt oxyhydroxide catalyst with abundant coordinatively unsaturated Co–O units. These local structures strengthen Co–O electronic interactions, generate oxygen-hole states and activate Co-centered unpaired spins, thereby enabling spin-conserved radical oxygen coupling. The resulting catalyst couples low-overpotential OER activity (185 mV at 10 mA cm−2) with efficient anion exchange membrane water electrolysis performance, delivering 6.35 A cm−2 at 2.0 V and sustained operation at 1 A cm−2 for 2000 h. This work establishes spin control in metal oxyhydroxides as a design principle for efficient and durable anion exchange membrane water electrolysis. Efficient oxygen evolution catalysts are needed for durable anion exchange membrane water electrolysis. Here, the authors report a reconstructed cobalt oxyhydroxide that uses spin-conserved radical oxygen coupling to enable efficient and stable water electrolysis at high current densities.
Mechanical adaptation is a fundamental yet poorly understood process in stromal tissue biology. Here, we identify a population of LGR5+ mechanically induced regulatory fibroblasts (LGR5+ MIRFs) in mouse and human dermis, whose induction requires a YAP/AP-1-dependent transcriptional program. LGR5+ MIRFs channel mechanical input toward adaptive tissue remodeling by coordinating extracellular matrix reorganization while restraining inflammation. Their ablation or fibroblast-specific deletion of Lgr5 converts adaptive stretching into pathological fibro-inflammation, while dermal Lgr5 overexpression enhances tissue extensibility. Mechanistically, we uncover a non-canonical LGR5-JAK1 interaction that suppresses JAK-STAT signaling, directly coupling mechanosensing to kinase pathway activity. Topical JAK1 inhibition recapitulates the pro-remodeling effects of LGR5+ MIRFs, suggesting a translatable therapeutic strategy for optimizing skin expansion, treating striae, and mitigating fibrotic disorders. Our work redefines LGR5 as a conserved stromal mechanoresponder and provides a new conceptual framework for understanding adaptive tissue plasticity under mechanical stress. Mechanical stress induces LGR5+ fibroblasts that promote adaptive tissue remodeling by limiting fibrosis through JAK1 modulation. The study reveals a conserved mechanism of adaptation to mechanical stress and suggests a strategy for regenerative therapy.
