Sustainable depolymerization of lignin into aromatic compounds using amphiphilic Anderson-type polyoxometalate catalysts.

Lignin serves as a primary abundant source of renewable aromatic compounds. Achieving efficient breakdown of lignin and retaining its aromatic properties is highly desirable but remains a challenging task. To address this challenge, we synthesized Anderson-type polyoxometalate (POM) catalysts, particularly [CTAC]2[CoMo6]. We then investigated the effectiveness of the POM catalysts in the oxidative depolymerization of larch lignin. Under conditions of 160 °C, 1.0 MPa oxygen atmosphere, and a catalyst-to-substrate ratio of 1:5, we achieved a monomer yield of phenolic compounds at 12.43 wt%. The unsaturated coordination sites of Mo5+ within the catalysts were identified as active sites, facilitating enhanced O2 adsorption and activation. The enhanced O2 adsorption significantly influenced the production of aromatic monomers from lignin. We observed that the catalysts effectively cleaved CC bonds in ß-O-4 dimer compounds using lignin dimer model compounds. Notably, the [CTAC]2[CoMo6] catalyst exhibited excellent stability across five cycles, maintaining its high efficiency in lignin depolymerization. This indicates that Anderson-type POM-based catalysts exhibit potential for sustainable conversion of biomass into valuable compounds and for enhancing lignin valorization processes.

Effect of dual antiplatelet therapy prolongation in acute coronary syndrome patients with both high ischemic and bleeding risk: insight from the OPT-CAD study.

Background: In current clinical practice, controversy remains regarding the clinical benefits of prolonged dual antiplatelet therapy (DAPT) in acute coronary syndrome (ACS) patients facing high risks of both ischemia and bleeding ("bi-risk") following percutaneous coronary intervention (PCI). This study aimed to investigate the feasibility of identifying a group of bi-risk ACS patients after PCI using the OPT-BIRISK criteria, emphasizing extended DAPT treatment safety and efficacy beyond 12 months in these bi-risk ACS after PCI in real-world conditions. Methods: This analysis compared extended DAPT and single antiplatelet therapy (SAPT) at 12-24 months in ACS patients undergoing PCI complicated with both ischemic and bleeding risk as defined by OPT-BIRISK criteria without premature DAPT discontinuation before 9 months or major clinical adverse events within 12 months. This was a post hoc analysis of the Optimal antiPlatelet Antiplatelet Therapy for Chinese Patients with Coronary Artery Disease (OPT-CAD) study. The main research outcome was the incidence of ischemic events within 12-24 months, which was determined as a composite of stroke, myocardial infarction, and cardiac death events. Through propensity score matching (PSM), groups were balanced. For the external validation of the OPT-BIRISK criteria to identify a bi-risk ACS patient, ischemic events, BARC 2, 3, 5 bleeding events, and BARC 3, 5 bleeding events at 5 years were analyzed. Results: The total number of ACS patients analyzed in this analysis was 7,049, of whom 4,146 (58.8%) were bi-risk patients and 2,903 (41.2%) were not. The frequency of ischemic events was significantly different between the two groups at 5 years (11.70% vs. 5.55%, P < 0.001), and the incidence of BARC 2,3,5 bleeding was significantly higher in the bi-risk group (6.90% vs. 4.03%, P < 0.001) than in the non-bi-risk group. Among the bi-risk patients without any clinical adverse events within 12 months that underwent extended DAPT treatment (n = 2,374, 75.7%) exhibited a lower risk of stroke at 12-24 months (1.10% vs. 2.10%, P = 0.036) relative to those that underwent SAPT (n = 763, 24.3%), while bleeding risk did not differ significantly between these groups. PSM cohort analysis results were consistent with those of overall group analyses. Conclusion: In conclusion, the findings showed that using the OPT-BIRISK criteria could help physicians identify ACS patients at a high risk of developing recurrent ischemia and bleeding episodes after PCI. Compared to antiplatelet monotherapy, a strategy of extended DAPT may offer potential benefits in lowering the risk of stroke without carrying a disproportionately high risk of serious bleeding problems among these patients who were event-free after a year of DAPT.