Precision Chemistry最新文献

ZnZrO _x is a promising oxide component for direct syngas conversion via oxide-zeolite bifunctional catalysis, while rational design of active centers within the composite oxide remains limited. In this study, through ab initio thermodynamics, molecular dynamics, and microkinetic modeling, we find that diverse subnanometer ZnO _x species, including single-site, single-chain, and single-layer configurations, can form on active ZrO₂ surfaces under the reaction conditions. These confined ZnO _x species weaken CO adsorption but enhance heterolytic H₂ dissociative adsorption, favoring continuous hydrogenation of CO to methanol over direct or H-assisted CO dissociation. For single-layer ZnO _x structures, a double-chain film grows on a monoclinic ZrO₂ (m-ZrO₂) surface while a graphene-like film emerges on tetragonal ZrO₂ (t-ZrO₂). These single-layer ZnO _x species exhibit higher methanol formation activity than their single-chain or single-site counterparts, which benefit from sufficient sites for adsorption of intermediates and a suitable space for bonding of H with C in CHO. Furthermore, the double-chain ZnO _x film confined on m-ZrO₂ exposes octahedral Zn_oct sites, which are more reactive than the triangular Zn_tri sites in the graphene-like ZnO _x on t-ZrO₂, despite both sites being nominally three-coordinate. These findings provide insights for the precise design of composite oxide/oxide catalysts through fine-tuning overlayer coverage and/or support surface properties.

The development of electrochemical energy storage systems with high-density storage sites is the key and core technology to achieve transformative breakthroughs in battery performance. Herein, we immobilize redox-active naphthalene diamides (TBNDI) within 2D graphdiyne (GDY) to construct carbon-based TBNDI-GDY composite electrodes. This approach creates a hierarchical ion diffusion pathway and enables tunable electronic modulation through a strategic molecular design. The multiredox center electrodes demonstrate prominent kinetic processes, superior interfacial compatibility, and fast desolvation capability. The as-prepared electrodes with pseudocapacitive processes display ultrahigh specific capacity up to 2079 mAh/g at 0.1 A/g, remarkable rate capacity, and ultralong stability for 10,000 cycles even at 5 A/g. Dynamic kinetic tracking and lithium active site visualization confirm that capacity contribution originates from reversible lithium-ion capture as well as Li-C orbital coupling in the sloping voltage regions, nanopore filling, and graphitic region interaction in the subsequent voltage region. Moreover, C=O-N groups with lone pair electron delocalization could modulate the electronic structure and promote reversible redox activities. Our findings highlight that the rational design of the ion diffusion interface from the basic chemical structure can provide giant evolution on the properties of the electrode material for high performance batteries.

Obesity is a global health problem that increases the risk of type 2 diabetes, cardiovascular diseases, fatty liver disease, and cancer. The pathological outcomes of obesity and the responses to weight loss interventions vary significantly among individuals. The use of noninvasive biomarkers is critical for the early risk prediction of diseases associated with obesity and monitoring disease progression. MicroRNAs (miRNAs) are small noncoding RNAs that play pivotal roles in biological processes of adipose development, inflammation, and function. Dysregulation of numerous miRNAs has been implicated in the pathogenesis of obesity and associated diseases. In addition to exerting their function in the cytoplasm, mature miRNAs can be packaged into vesicles, released into extracellular space and body fluids, and act as paracrine and endocrine factors mediating intercellular and interorgan crosstalk. Encapsulation of miRNAs in extracellular vesicles (EVs) protects them from degradation and enhances their stability in body fluids. Moreover, the unique EV-miRNA signature reflects the state of the origin cells and is functionally related to disease pathology, supporting their potential as sensitive and specific biomarkers for clinical diagnostics. Adipose tissue is the main source of circulating EV-miRNAs in Obesity. Here we highlight the implication of adipose tissue-derived EV-miRNAs in metabolic disorders associated with obesity. Current understanding of the molecular mechanisms governing the sorting of miRNAs into EVs and recent advancements in relevant techniques are reviewed. In addition, limitations and future perspectives in this field are discussed.