Molecular Dynamics Insights into Water Transport Mechanisms in Polyamide Membranes: Influence of Cross-Linking Degree.

Polyamide (PA) membranes are widely utilized in desalination and water treatment applications, yet the mechanisms underlying water transport within these amorphous polymer materials remain insufficiently understood. To gain more insight into these problems on a microscopic scale, we employ molecular dynamics (MD) simulations to analyze the relationship between the structural properties and the water permeation behavior of PA membranes. Two distinct atomistic models of PA membranes are developed by controlling their degrees of cross-linking (DC).

Eight new cycloartane triterpenoids from Beesia calthifolia with hepatoprotective effects against D-galactosamine induced L02 cell damage.

Fourteen 20,24-epoxy-cycloartane triterpenoids, including eight new ones (1-8), were isolated from 95% ethanol extract of the rhizomes of Beesia calthifolia. Their structures were determined by spectroscopic and chemical methods, especially 2D NMR and HRMS techniques. Among them, four new compounds (1-4) possess carbonyl groups at C-16, which were rarely found in cycloartane triterpenoids from this genus.

Five new cycloartane triterpenoids from Beesia calthifolia.

Phytochemical study on rhizomes of Beesia calthifolia resulted in the isolation of five new (1-5) and three known (6-8) cycloartane triterpenoids possessing a hemiketal or ketal group at C-24 from the EtOAc fraction of 95% ethanol extract. Their structures were determined by spectroscopic and chemical methods, especially HRMS and 2D NMR techniques. Compounds 3 and 4 showed potential hepatoprotective activities against D-galactosamine induced human hepatic L02 cell damage.