A field plot experiment in a calcareous soil with wheat and maize rotation was carried out for 2 yr. The study aimed to investigate the effects of biosolids （sewage sludge or chicken manure） application on nitrogen ...A field plot experiment in a calcareous soil with wheat and maize rotation was carried out for 2 yr. The study aimed to investigate the effects of biosolids （sewage sludge or chicken manure） application on nitrogen （N） and phosphorus （P） accumulation in soils and to develop a model for the effects of biosolids application on available P （Olsen-P） accumulation in soils, by which the quantities of biosolids that can be safely applied to agricultural soils were estimated. The results showed that heavy application of biosolids to agricultural soils based on the N requirement of a wheat-maize rotation cropping system will oversupply P. Soil total N was increased by 0.010 g kg-1 at application rate of 1 ton sewage sludge per hectare. The high ratio of N to P in grains of wheat and maize （from 4.0 to 7.6） and low ratio of N to P in biosolids （〈2） led to more surplus P accumulated in soils. Although plant yields and P uptake by plants increased with increasing quantities of applied biosolids in soils, there was still an average 2.87 mg kg-1 increase in Olsen-P in the plough layer treated with biosolids for every 100 kg P ha-1 surplus. A predictive model was developed based upon the initial Olsen-P in soils, P input rates, crop yield, soil pH, and cultivation time. From the model, it is suggested that sewage sludge could be applied to calcareous soils for 12 yr using the recommended application rate （9 tons ha-1 yr-1）. The field results will be helpful in achieving best management of biosolids application for agricultural production and environmental protection.展开更多
To improve the encapsulation efficiency and minimize particle agglomeration of liposomes, rapid expansion from supercritical to surfactant solution（RESSS） was applied to self-assembly of liposomes entrapping hinesol...To improve the encapsulation efficiency and minimize particle agglomeration of liposomes, rapid expansion from supercritical to surfactant solution（RESSS） was applied to self-assembly of liposomes entrapping hinesol in supercritical carbon dioxide（SC-CO2） medium. In the process, the solution of liposomal materials and hinesol dissolved in the mixture of SC-CO2/ethanol was sprayed into a surfactant solution. The surfactant provided stabilization for liposomes by preventing bubbles overflowing and liposomes agglomeration during the spraying process. The encapsulating performance and particle size distribution of liposomes could be controlled by changing expansion processing conditions. When the solution was sprayed into a 5.0% Poloxamer 188 solution at a flow rate of 2 L/min, the entrapment efficiency and average particle size of liposomes were found to be 88.26% and 124 nm, respectively, which came to the standards of Chinese pharmacopoeia. The results show RESSS process provides an innovative method for formation of liposomes incorporating valid compositions extracted from the Chinese traditional medicines in SC-CO2 medium.展开更多
基金the National Natural Science Foundation of China (30971868)the Beijing Drainage Group Co. Ltd., China
文摘A field plot experiment in a calcareous soil with wheat and maize rotation was carried out for 2 yr. The study aimed to investigate the effects of biosolids （sewage sludge or chicken manure） application on nitrogen （N） and phosphorus （P） accumulation in soils and to develop a model for the effects of biosolids application on available P （Olsen-P） accumulation in soils, by which the quantities of biosolids that can be safely applied to agricultural soils were estimated. The results showed that heavy application of biosolids to agricultural soils based on the N requirement of a wheat-maize rotation cropping system will oversupply P. Soil total N was increased by 0.010 g kg-1 at application rate of 1 ton sewage sludge per hectare. The high ratio of N to P in grains of wheat and maize （from 4.0 to 7.6） and low ratio of N to P in biosolids （〈2） led to more surplus P accumulated in soils. Although plant yields and P uptake by plants increased with increasing quantities of applied biosolids in soils, there was still an average 2.87 mg kg-1 increase in Olsen-P in the plough layer treated with biosolids for every 100 kg P ha-1 surplus. A predictive model was developed based upon the initial Olsen-P in soils, P input rates, crop yield, soil pH, and cultivation time. From the model, it is suggested that sewage sludge could be applied to calcareous soils for 12 yr using the recommended application rate （9 tons ha-1 yr-1）. The field results will be helpful in achieving best management of biosolids application for agricultural production and environmental protection.
基金Supported by the National Natural Science Foundation of China(No.20606013)the Produce-learn-research Project of Shenzhen Scinence and Technology Program(No.2008342)the Fundamental Research Project of Shenzhen Science and Technology, China(No.JC200903120089A)
文摘To improve the encapsulation efficiency and minimize particle agglomeration of liposomes, rapid expansion from supercritical to surfactant solution（RESSS） was applied to self-assembly of liposomes entrapping hinesol in supercritical carbon dioxide（SC-CO2） medium. In the process, the solution of liposomal materials and hinesol dissolved in the mixture of SC-CO2/ethanol was sprayed into a surfactant solution. The surfactant provided stabilization for liposomes by preventing bubbles overflowing and liposomes agglomeration during the spraying process. The encapsulating performance and particle size distribution of liposomes could be controlled by changing expansion processing conditions. When the solution was sprayed into a 5.0% Poloxamer 188 solution at a flow rate of 2 L/min, the entrapment efficiency and average particle size of liposomes were found to be 88.26% and 124 nm, respectively, which came to the standards of Chinese pharmacopoeia. The results show RESSS process provides an innovative method for formation of liposomes incorporating valid compositions extracted from the Chinese traditional medicines in SC-CO2 medium.
