Polyacrylic acid (PAA) hydrogel prepared by radical polymerization in a clean and extremely simple way was used to adsorb U(VI) ions from aqueous solutions. Fourier transform infrared spectroscopy (FTIR) characterization demonstrated that the PAA hydrogels were successfully synthesized, FTIR and transmission electron microscope (TEM) characterization illustrated the adsorption mechanism, and the adherence of the U(VI) ions on PAA was confirmed by X-ray photoelectron spectroscopy (XPS) energy dispersive X-ray (EDX). Batch experiments with various pH, initial concentration and contact time were conducted to evaluate the adsorption performance. The adsorption kinetics of the PAA hydrogels followed a pseudo-second-order model and exhibited a 3-stage intraparticle diffusion mode. Equilibrium data were best described by a Langmuir model, and the estimated maximum adsorption capacity for the adsorbent was 445.11 mg g⁻¹. Moreover, the U(VI) loaded adsorbent could be regenerated using 0.1 M HNO₃ acid solution, and the regenerated adsorbent after five cycles could retain 90.91% of the adsorption capacity of the fresh adsorbent. The results suggested that the PAA hydrogels could be considered to be very effective and promising materials for U(VI) removal from waste water.

A pentacyclic triterpene natural product, ursolic acid and its prodrug US597 inhibit targets within cell adhesion pathway and prevent cancer metastasis A pentacyclic triterpene natural product, ursolic acid and its prodrug US597 inhibit targets within cell adhesion pathway and prevent cancer metastasis

Ursolic acid (UA) is a naturally bioactive product that exhibits potential anticancer effects. The relatively safe and effective molecule intrigued us to explore a way to further improve its anti-cancer activity and tumor-targeting specificity. In the present study, a series of structural modifications of UA was achieved, which resulted in significant increase in growth inhibition on various cancer cell lines with minimal effects on normal cells. The leading molecule US597 (UA-4) caused depolarization of mitochondrial membrane potential, cell arrest in G0/G1 phase and apoptosis/necrosis in a dose-dependent manner. Structural docking suggested that the carbon chains of the modified UA derivatives compete strongly with glucose for binding to glucokinase, the key glycolysis enzyme presumably active in cancer cells. The combination of 2-deoxy-D-glucose (2-DG) and UA-4 induced cell cycle arrest in G2/M phase, promoted caspase-dependent cell death, reduced hexokinase activity, aggravated depletion of intracellular ATP, decreased lactate production and synergistically inhibited cancer cell growth in vitro (HepG2) and in vivo (H22). Collectively, our findings suggest that the structural modification enhances efficacy and selectivity of UA, and the combination of UA-4 with 2-DG produces synergistic inhibition on hepatoma cell proliferation by dual targeting of apoptosis and glycolysis.