Constructing Functional Radiation-Resistant Thorium Clusters for Catalytic Redox Reactions.

When catalytic reactions are interfered with by radiation sources, thorium clusters are promising as potential catalysts due to their superior radiation resistance. However, there is currently very little research on the design synthesis and catalytic application of radiation-stable thorium clusters. In this work, we have elaborately engineered and fabricated three high-nuclear thorium cluster catalysts denoted as Th12L3-MA12, Th12L3-MA6-BF6, and Th12L3-Fcc12, which did not undergo any significant alterations in their molecular structures and compositions after irradiation with 690 kGy γ-rays. We systematically investigated the photocatalytic/thermocatalytic properties of these radiation-resistant thorium clusters for the first time and found that γ-rays could not alter their catalytic activities. In addition, it was found that ligand engineering could modulate the catalytic activity of thorium clusters, thus expanding the range of catalytic applications of thorium clusters, including reduction reactions (nitroarene reduction) and some oxidation reactions (N-heterocyclic oxidative dehydrogenation and diphenylmethane oxidation). Meanwhile, all of these organic transformation reactions achieved a >80% conversion and nearly 100% product selectivity. Radiation experiments combined with DFT calculations showed that the synergistic catalysis of thorium-oxo core and ligands led to the generation of specific active species (H+, O2•-, or tBuO/tBuOO•) and activation of substrate molecules, thus achieving superior catalytic performance. This work is not only the first to develop radiation-resistant thorium cluster catalysts to perform efficient redox reactions but also provides design ideas for the construction of high-nuclearity thorium clusters under mild conditions.

Synthesis of Isotypic Giant Polymolybdate Cages for Efficient Photocatalytic C-C Coupling Reactions.

The construction of isotypic high-nuclearity inorganic cages with identical pristine parent structure and increasing nuclearity is highly important for molecular growth and structure-property relationship study, yet it still remains a great challenge. Here, we provide an in situ growth approach for successfully synthesizing a series of new giant hollow polymolybdate dodecahedral cages, Mo250, Mo260-I, and Mo260-E, whose structures are growth based on giant polymolybdate cage Mo240. Remarkably, they show two pathways of nuclear growth based on Mo240, that is, the growth of 10 and 20 Mo centers on the inner and outer surfaces to afford Mo250 and Mo260-I, respectively, and the growth of 10 Mo centers both on the inner and outer surfaces to give Mo260-E. To the best of our knowledge, this is the first study to display the internal and external nuclear growth of a giant hollow polyoxometalate cage. More importantly, regular variations in structure and nuclearity confer these polymolybdate cages with different optical properties, oxidative activities, and hydrogen atom transfer effect, thus allowing them to exhibit moderate to excellent photocatalytic performance in oxidative cross-coupling reactions between different unactivated alkanes and N-heteroarenes. In particular, Mo240 and Mo260-E with better comprehensive abilities can offer the desired coupling product with yield up to 92% within 1 h.

Decreased expression of KLF6 in ectopic endometrial stromal cells contributes to endometriosis progression by targeting CTNNB1.

Despite decades of research, endometriosis remains a mysterious gynecological disease with unknown etiology and pathogenesis. Krüppel-like Factor 6 (KLF6), a transcription factor, has a wide expression profile and regulates a variety of biological processes. Here, we investigated the expression and function of KLF6 and its possible regulatory mechanisms in endometriosis. To determine the function of KLF6, knockdown and overexpression experiments were performed in eutopic endometrial stromal cells (EU-ESCs) and ectopic endometrial stromal cells (EC-ESCs), respectively. Cell viability, apoptosis, migration, invasion, and angiogenesis assays were conducted in ESCs. ChIP-sequencing and mRNA-sequencing were performed to investigate the functional mechanism of KLF6 in regulating ESCs. We found that KLF6 was highly expressed in eutopic endometrium of endometriosis patients, compared with ectopic endometrium. Similarly, the same was true in EU-ESCs, which was compared with EC-ESCs. Overexpression of KLF6 significantly suppressed EC-ESC proliferation, migration and invasion and induced cell apoptosis, while knockdown of KLF6 resulted in the opposite effects on EU-ESCs. Overexpression of KLF6 significantly inhibited EC-ESC angiogenesis. Mechanistically, the results of ChIP sequencing and mRNA sequencing revealed that CTNNB1 may be a transcriptional target regulated by KLF6. Reintroduction of KLF6 reversed the effects of KLF6 knockdown on EU-ESCs. KLF6 inhibited the proliferation, migration and angiogenesis of EC-ESCs by inhibiting the expression of CTNNB1. Our findings provided a new perspective on the role of KLF6 in endometriosis progression and inspire potential targeted therapeutic strategies.

Air-sea exchange of PAHs in the Taiwan Strait: Seasonal dynamics and regulation mechanisms revealed by machine learning approach.

In this study, to understand the seasonal dynamics of air-sea exchange and its regulation mechanisms, we investigated polycyclic aromatic hydrocarbons (PAHs) at the air-sea interface in the western Taiwan Strait in combination with measurements and machine learning (ML) predictions. For 3-ring PAHs and most of 4- to 6-ring, volatilization and deposition fluxes were observed, respectively. Seasonal variations in air-sea exchange flux suggest the influence of monsoon transitions. Results of interpretable ML approach (XGBoost) indicated that volatilization of 3-ring PAHs was significantly controlled by dissolved PAH concentrations (contributed 24.0 %), and the gaseous deposition of 4- to 6-ring PAHs was related to more contaminated air masses originating from North China during the northeast monsoon. Henry's law constant emerged as a secondary factor, influencing the intensity of air-sea exchange, particularly for low molecular weight PAHs. Among environmental parameters, notably high wind speed emerges as the primary factor and biological pump's depletion of PAHs in surface seawater amplifies the gaseous deposition process. The distinct dynamics of exchanges at the air-water interface for PAHs in the western TWS can be attributed to variations in primary emission intensities, biological activity, and the inconsistent pathways of long-range atmospheric transport, particularly within the context of the monsoon transition.