[Responses of Riverine Phosphorus Exports to Land Use and Hydrological Regime in the Jiulong River Watershed].

In-situ monitoring, geographic information technology (GIS), watershed model, and statistical techniques were coupled in this study to explore the responses of riverine phosphorus exports to land use pattern and hydrological regime in the Jiulong River Watershed (JRW). We analyzed riverine phosphorus concentrations and exports from March 2015 to February 2017 across a land use gradient spanning 14 monitored sampling sites. Results showed that significantly spatial and seasonal variations of phosphorus concentrations and exports were observed in JRW. Mean phosphorus concentrations and exports were the highest in the agricultural watershed, followed by the urban watershed, whereas the West River reach had higher mean phosphorus concentration and export than the North River reach. Mean concentrations of phosphorus were higher in spring and winter, whereas lower concentrations were observed in autumn and summer. Phosphorus exports were higher in spring and summer, consistent with the seasonal trend of runoff. Phosphorus concentrations and exports had negative correlations with percentages of forest and bare land, and were positively correlated with cropland and orchard. The responses of riverine phosphorus to land use types and hydrological regime varied across seasons, whereas the relationships between phosphorus concentrations/exports and land use or runoff were the strongest in summer, suggesting that non-point source pollution associated with agricultural activities would be the critical source of riverine phosphorus and an increase in forest percentage could be useful for improving water quality. Overall, the spatiotemporal patterns of phosphorus exports were affected by land use pattern, as well as the characteristics of the hydrological regime.

Bioactive glass functionalized chondroitin sulfate hydrogel with proangiogenic properties.

Blood vessels play an important role in bone defect repair and growth, and a critical challenge of bone defect repair is the promotion of blood vessel formation. Most of the current methods promote vascularization by adding specific growth factors, which are costly and easy to inactivate. In this study, we developed a covalently cross-linked aminated bioactive glass nanoparticle-chondroitin sulfate methacrylate (ABGN-CSMA) organic-inorganic composite hydrogel with angiogenic properties. The amino groups of the ABGNs form covalent bonds with the carboxyl groups on CSMA. Surface amination modification of BGNs not only improved the dispersion of BGNs in CSMA but also significantly improved the mechanical properties of the composite hydrogel. The largest storage modulus (1200 Pa), the largest loss modulus (560 Pa) and the strongest resistance to deformation of the hydrogel are seen at 10% concentration of ABGNs. Simultaneously, the local pH stability and sustained ion release of the composite hydrogel are conducive to cell adhesion, proliferation, and angiogenesis. This work provides evidence for the development of covalently cross-linked organic-inorganic composite hydrogels with angiogenic properties.