The emergent plants may differ in their capacity to assimilate nutrients from eutrophic water bodies, so the utilization of suitable emergent plants is the key part for successful restoration of shallow eutrophic lakes and rivers. This research applied the depletion method to study the kinetics of uptake of nutrient (H2PO4−, NH4+, NO3−) in different nutrient stresses by the five emergent aquatic plants (Acorus calamus L., Typha orientalis, Lythrum salicaria L., Sagittaria trifolia L., Alisma plantago-aquatica Linn) in the riverine zones of Dashi River (39°30′–39°40′ N, 115°59′–116°5′ E), a shallow eutrophic river located in Fangshan District, Beijing. The results showed that at the three phosphorus levels, A. calamus and A. plantago-aquatica had the highest maximum uptake rate values for NH4+ under low to moderate phosphorus conditions, and high phosphorus, respectively. T. orientalis had the highest maximum uptake rate values for NO3− at all phosphorus concentrations, while the Michaelis-Menten constant values of L. salicaria and A. plantago-aquatica were smaller. At the three nitrogen levels, the maximum uptake rate values for H2PO4− were the greatest for A. plantago-aquatica at the low to moderate nitrogen levels and L. salicaria at high levels. Meanwhile, T. orientalis and L. salicaria had the smallest Michaelis-Menten constant values. In this study, nitrogen microbial transformations, such as nitrification, denitrification and their coupling were not measured and their role in measuring kinetics was not assessed. Thus, achieved results shall be considered as a synthesis of several processes mediated by plants, a theoretical guidance to the selection of plant species for phytoremediation of polluted water bodies with different nutrient stresses for quality improvement around the diverse rivers in Haihe River basin.
To improve the water solubility and dissolution rate, genipin was nanocrystallized by an emulsion solvent evaporation method, followed by freeze-drying. The optimization condition of nanocrystallization process was carried out by single-factor experiment. The effects of five experimental parameters, such as concentration of surfactants the proportion of water to organic phase, homogenate speed and time, homogenization pressure and times, and the proportion of genipin to lyoprotectants on the mean particle size (MPS) of genipin nanoparticles, were investigated. Under the optimum conditions by single-factor experiments, genipin nanoparticles with an MPS of 59.8 nm were obtained. The genipin nanoparticles were characterized by SEM, FTIR, XRD, DSC, solvent residue, drug purity test, dissolution testing, and bioavailability analysis. The analysis results indicated that the chemical structure of genipin nanoparticles was unchanged, but the crystallinity was reduced. The solubility of genipin nanoparticles was 9.05 times of the raw drug. In addition, the residual amounts of chloroform and ethanol were separately less than the ICH limit for class II, and the oral bioavailability of the genipin nanoparticles powder was 7.99 times of raw genipin. According to the results above, genipin nanoparticles show the potential application value of its oral absorption.
TotalPanaxnotoginsenosides nanoparticles, typical multicomponent extracts from traditional Chinese medicine, were prepared with a supercritical antisolvent (SAS) process using ethanol as solvent and carbon dioxide as antisolvent. The optimum conditions were determined to be as follows: TPNS solution concentration of 2.5 mg/mL, TPNS solution flow rate of 6.6 mL/min, precipitation temperature of 40°C, and precipitation pressure of 20 MPa. Under the optimum conditions, TPNS nanoparticles with a MPS of 141.5 ± 18.2 nm and total saponins amounts (TSA) of 78.9% were obtained. The TPNS nanoparticles obtained were characterized by scanning electron microscopy (SEM), dynamic light scattering (DLS), Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimeters (DSC), and high performance liquid chromatography (HPLC). The results showed that the chemical and crystal structure of the obtained TPNS nanoparticles has not changed. Dissolutionin vitrostudies showed that the solubility and dissolution rate of notoginsenosides R1 and ginsenoside Rb1 in TPNS nanoparticles are higher than these in raw TPNS, with no obvious difference in Rg1. These results suggest that TPNS nanoparticles can be helpful to the improvement of its bioavailability for the treatment of cardiovascular diseases.
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