Nanosizing by wet beads milling is one of the methods to improve the solubility of poorlywater soluble compounds[1,2].Hydrophilic polymers,such as Hydroxypropylcellulose-SSL(HPC),Polyvinylalcohol(PVA),and Polyvinylpyr...Nanosizing by wet beads milling is one of the methods to improve the solubility of poorlywater soluble compounds[1,2].Hydrophilic polymers,such as Hydroxypropylcellulose-SSL(HPC),Polyvinylalcohol(PVA),and Polyvinylpyrrolidone-K30(PVP)etc.are used as dispersion stabilizer to prevent aggregation of nanoparticles.However,there are many compounds that cannot be dispersed by ordinary dispersion stabilizers.In this study,we used Povacoat?as a dispersion stabilizer for several poorly water soluble compounds milled to nanoparticles.The influences of aggregation of the nanoparticles on the dissolution behavior and the oral absorption of the compoundswere studied using formulations with high and low dispersion characters.展开更多
Raising cattle in feedlots is becoming more common in Argentina, but there is little information available about the effects of this practice on soil phosphorus (P) dynamics. In this study, concentrations of water and...Raising cattle in feedlots is becoming more common in Argentina, but there is little information available about the effects of this practice on soil phosphorus (P) dynamics. In this study, concentrations of water and Bray -1 extractable soil P were quantified in a feedlot (upper and lower slope positions in the feedlot pen), runoff area and pasture during 2006 - 2008. The feedlot showed higher P concentrations in all P forms, soluble reactive P, soluble nonreactive, total soluble P, and Bray-P1 when compared to runoff area and pasture. Most of the total soluble P was soluble reactive P from the soil in the feedlot and the runoff area, while soluble nonreactive P predominated in the pasture. Concentrations of total soluble P were elevated in the feedlot at the soil surface, ranging on average from 158.71 to 245.86 mg?P?kg?1, and had a rapid decrease within the first 20 cm and remained relatively low, about 25.53 - 27.33 mg?P?kg?1. The evidence that total soluble P concentration in the feedlot was significantly (p < 0.05) higher than that registered in the pasture at 20 - 40 and 40 - 60 cm soil depth suggests a potential transfer of P through the soil from the surface. Although the feedlot had a moderate increase of 23.05 to 24.55 mg?P?kg?1 from the background concentration, it may represent a long-term source of increased nutrient loading to groundwater. Soil extractable Bray-1 P in the top 0 - 2.5 cm fluctuated from 659.26 to 45.36 mg?P?kg?1 in the feedlot and pasture, respectively. The relationship between soil P extracted by test and TSP was linear, and correlation coefficient was r2 = 0.95.展开更多
文摘Nanosizing by wet beads milling is one of the methods to improve the solubility of poorlywater soluble compounds[1,2].Hydrophilic polymers,such as Hydroxypropylcellulose-SSL(HPC),Polyvinylalcohol(PVA),and Polyvinylpyrrolidone-K30(PVP)etc.are used as dispersion stabilizer to prevent aggregation of nanoparticles.However,there are many compounds that cannot be dispersed by ordinary dispersion stabilizers.In this study,we used Povacoat?as a dispersion stabilizer for several poorly water soluble compounds milled to nanoparticles.The influences of aggregation of the nanoparticles on the dissolution behavior and the oral absorption of the compoundswere studied using formulations with high and low dispersion characters.
文摘Raising cattle in feedlots is becoming more common in Argentina, but there is little information available about the effects of this practice on soil phosphorus (P) dynamics. In this study, concentrations of water and Bray -1 extractable soil P were quantified in a feedlot (upper and lower slope positions in the feedlot pen), runoff area and pasture during 2006 - 2008. The feedlot showed higher P concentrations in all P forms, soluble reactive P, soluble nonreactive, total soluble P, and Bray-P1 when compared to runoff area and pasture. Most of the total soluble P was soluble reactive P from the soil in the feedlot and the runoff area, while soluble nonreactive P predominated in the pasture. Concentrations of total soluble P were elevated in the feedlot at the soil surface, ranging on average from 158.71 to 245.86 mg?P?kg?1, and had a rapid decrease within the first 20 cm and remained relatively low, about 25.53 - 27.33 mg?P?kg?1. The evidence that total soluble P concentration in the feedlot was significantly (p < 0.05) higher than that registered in the pasture at 20 - 40 and 40 - 60 cm soil depth suggests a potential transfer of P through the soil from the surface. Although the feedlot had a moderate increase of 23.05 to 24.55 mg?P?kg?1 from the background concentration, it may represent a long-term source of increased nutrient loading to groundwater. Soil extractable Bray-1 P in the top 0 - 2.5 cm fluctuated from 659.26 to 45.36 mg?P?kg?1 in the feedlot and pasture, respectively. The relationship between soil P extracted by test and TSP was linear, and correlation coefficient was r2 = 0.95.
