Guangxi Normal University

This study employed Raman spectroscopy combined with characteristic-peak-intensity-ratio analysis and a novel difference-spectral-statistical-mapping (DSSM) method to elucidate dynamic functional group transformations in flaxseed oil during various frying temperatures (100-185 °C) and repeated frying frequencies (1-5 times). The multiple linear regression models of I₉₆₉/I₁₂₆₆ with I₉₆₉/I₁₃₀₀ and I₉₆₉/I₁₄₄₁ exhibit high correlation coefficients (R²) between 0.93 and 0.94, suggesting that the changes in trans-CC are closely related to the variations in cis-CC and methylene (CH₂), which provides key insights for optimizing industrial detection models and fundamental oxidation kinetics research. DSSM identified hidden oxidation features, including epoxy groups and conjugated trienes, visualizing their evolution trends, offering critical spectroscopic evidence for assessing the quality degradation of frying oils. These methods provide theoretical support for real-time and rapid monitoring of the dynamic changes of functional groups in frying oil, taking a key step towards industrial level real-time monitoring of Raman spectroscopy technology.

Nine undescribed compounds, including two sesquiterpenoid-substituted flavanols (1 and 2), a flavan glucoside (3), and three pairs of lignan enantiomers (4a/4b‒6a/6b), together with 22 known flavonoid derivatives (7a/7b and 8‒27) were isolated from an EtOH extract of the rattans of Phanera championii Benth. Compounds 1 and 2 are extremely rare, featuring a unique combination of flavan-3-ols linked with sesquiterpenoids. Chiral HPLC analysis with a Daicel Chiralpak AD-H column was applied to the separation of four pairs of lignan enantiomers. The absolute configurations of all the undescribed compounds were identified by alkaline hydrolysis, acid hydrolysis, experimental and calculated ECD methods. The results of anti-neuroinflammatory activity indicated that five compounds (16, 22, and 24‒26) exhibited potent inhibitory effects on nitric oxide release in BV-2 microglial cells induced by LPS, with IC₅₀ values ranging from 0.5 to 12.7 μM. Their preliminary structure-activity relationships were discussed.

Conventional carbon dioxide (CO₂) valorization requires concentrated streams, but most sources are dilute, necessitating energy-intensive and costly capture steps. Here, we report a direct strategy for utilizing dilute CO₂ by employing a copper-based porous nano-reactors (Cu@POP-IS), which integrates the capture and activation steps. These reactors possesse an average pore size of 1.3 nm and exhibits a CO₂ adsorption capacity of 55.77 cm³/g at 273 K. More importantly, the functional sites within its framework enable the simultaneous catalytic conversion of dilute CO₂ stream (8-35 vol%) in actual waste gases and regeneration of the nano-reactors, achieving an oxazolidinone yield of 61-99%. This result demonstrates the dual functionality of the nano-reactors (capturing and activating CO₂) and underscores the integrated energy and economic advantages of our approach. Furthermore, we reveal that CO₂ reactivity is modulated by its interactions with specific active sites. This finding provides a general principle for the rational design of functionalized nano-reactors to advance the resource-oriented utilization of CO₂.