Leaching behaviour and mechanism of U, 226Ra and 210Pb from uranium tailings at different pH conditions.

A large number of radionuclides remain in uranium tailings, and U, 226Ra and 210Pb leach out with water chemistry, causing potential radioactive contamination to the surrounding environment. In this paper, uranium tailings from a uranium tailings pond in southern China were collected at different depths by means of borehole sampling, mixed and homogenised, and analysed for mineral and chemical composition, microscopic morphology, U, 226Ra and 210Pb fugacity, static leaching and dynamic leaching of U, 226Ra and 210Pb in uranium tailings at different pH conditions. The variation of U, 226Ra and 210Pb concentrations in the leachate under different pH conditions with time was obtained, and the leaching mechanism was analysed. The results showed that the uranium tailings were dominated by quartz, plagioclase and other minerals, of which SiO2 and Al2O3 accounted for 65.45% and 13.32% respectively, and U, 226Ra and 210Pb were mainly present in the residue form. The results of the static leaching experiments show that pH mainly influences the leaching of U, 226Ra and 210Pb by changing their chemical forms and the particle properties of the tailings, and that the lower the pH the more favourable the leaching. The results of dynamic leaching experiments during the experimental cycle showed that the leaching concentration and cumulative release of U, 226Ra and 210Pb in the leach solution were greater at lower pH conditions than at higher pH conditions, and the leaching of U, 226Ra and 210Pb at different pH conditions was mainly from the water-soluble and exchangeable states. The present research results are of great significance for the environmental risk management and control of radioactive contamination in existing uranium tailings ponds, and are conducive to ensuring the long-term safety, stability and sustainability of uranium mining sites.

Improving the functionality of chitosan-based packaging films by crosslinking with nanoencapsulated clove essential oil.

The study aimed to obtain chitosan composite films with gratifying physical and functional properties. First, we developed a Pickering emulsion containing clove essential oil (CEO)-loaded nanoparticles with 1:2 (w/w) zein and sodium caseinate (NaCas). We found that in this ratio, the CEO-loaded zein-NaCas (C/ZN) nanoparticles had smaller particle size, proper polydispersity index (PDI) and zeta potential as well as higher encapsulation efficiency. Then, the acquired C/ZN nanoparticles were incorporated into chitosan film at three levels (0.2%, 0.4% and 0.6%), reducing the water vapor permeability to 4.62 × 10-6 g·s-1·m-1·Pa. Also, the tensile strength and break elongation of chitosan films were increased, reaching 38.67 MPa and 1.56%, respectively. The infrared spectroscopy verified that the intermolecular hydrogen bonds exist between chitosan and C/ZN nanoparticles. The chitosan composite films showed a controlled-release property of CEO in 96 h. Finally, the chitosan composite films showed the improved antibacterial property by creating larger inhibition zones against Escherichia coli (3.29 mm) and Staphylococcus aureus (6.15 mm). In general, we improved the water resistance, light blocking, mechanical strength, controlled-release and antibacterial properties of chitosan film with C/ZN nanoparticles. The current edible antibacterial films have great potential on applications for food preservation and food delivery system.

Hemin from porcine blood effectively stabilized color appearance and odor of prepared pork chops upon repeated freeze-thaw cycles.

This study was designed to evaluate changes in color following pork chop supplementation with porcine hemin, astaxanthin and paprika red in response to repeated freeze-thaw processes. Surface color analyses revealed that hemin significantly enhanced the appearance of the pork chops (P < 0.05), and the coloring efficiency of 0.10% hemin was similar to that of 0.20% astaxanthin and 0.08% paprika red. Sensory evaluations conducted on both raw and fried chops showed that hemin and astaxanthin significantly enhanced the overall acceptability of the chops before and after cooking. The color stability of the pork chops was also evaluated, and the results suggested that the hemin-colored chops were the most stable among the three, upon repeated freeze-thaw cycles. The electronic nose showed that the odor of the hemin-colored samples after 0, 3, and 7 freeze-thaw cycles was better than that of the other two groups. In conclusion, hemin may be a superior supplement for the large scale preparation of prepared pork chop.

Premature Physiologic Aging as a Paradigm for Understanding Increased Risk of Adverse Health Across the Lifespan of Survivors of Childhood Cancer.

The improvement in survival of childhood cancer observed across the past 50 years has resulted in a growing acknowledgment that simply extending the lifespan of survivors is not enough. It is incumbent on both the cancer research and the clinical care communities to also improve the health span of survivors. It is well established that aging adult survivors of childhood cancer are at increased risk of chronic health conditions, relative to the general population. However, as the first generation of survivors age into their 50s and 60s, it has become increasingly evident that this population is also at risk of early onset of physiologic aging. Geriatric measures have uncovered evidence of reduced strength and speed and increased fatigue, all components of frailty, among survivors with a median age of 33 years, which is similar to adults older than 65 years of age in the general population. Furthermore, frailty in survivors independently increased the risk of morbidity and mortality. Although there has been a paucity of research investigating the underlying biologic mechanisms for advanced physiologic age in survivors, results from geriatric populations suggest five biologically plausible mechanisms that may be potentiated by exposure to cancer therapies: increased cellular senescence, reduced telomere length, epigenetic modifications, somatic mutations, and mitochondrial DNA infidelity. There is now a critical need for research to elucidate the biologic mechanisms of premature aging in survivors of childhood cancer. This research could pave the way for new frontiers in the prevention of these life-changing outcomes.