The modern characterizing techniques, which were used forthe determination of the structure of pharmaceutical substancesand products in this presentation, were small angleX-ray scattering (SAXS), photon correlation sp...The modern characterizing techniques, which were used forthe determination of the structure of pharmaceutical substancesand products in this presentation, were small angleX-ray scattering (SAXS), photon correlation spectroscopy (PCS)and transmission electron microscopy (TEM).Different pharmaceutical substances and products such asmodel membranes from fishes, reptiles or carrier systems suchas liposomes, emulsion, and self-emulsifying drug deliverysystems (SEDDs) were characterized in our group by using SAXSfrom a synchrotron source.展开更多
As a widely prescribed anti diabetic drug, pioglitazone belongs to class II under BCS and exhibits low and variable oral bioavailability due to its poor aqueous solubility. Its oral absorption is dissolution rate limi...As a widely prescribed anti diabetic drug, pioglitazone belongs to class II under BCS and exhibits low and variable oral bioavailability due to its poor aqueous solubility. Its oral absorption is dissolution rate limited, and its solubility and dissolution rate need to be enhanced in order to increase its oral bioavailability. In the present study, we aimed to screen various oils, surfactants and cosolvents. The highest solubility was observed in Labrafac, Tween-80 and propylene glycol. Then the feasibility of formulating pioglitazone SEDDS was evaluated, and the effect of dilution on the dissolution rate and dissolution efficiency of pioglitazone was also analyzed. A comparative evaluation of pioglitazone from SEDDS was made in SGF and 1% SLS. Dissolution of pioglitazone from SEDDS was rapid and higher compared with pure drug. The rate and extent of release of pioglitazone hydrochloride from stable SEDDS （F1） were higher in 1% SLS compared with SGF. The FTIR spectra proved that there was on chemical interaction between excipients and drug. SEM studies confirmed that the size was small and spherical.展开更多
Sediment delivery ratio can be used as a measure of sediment connectivity and it can be linked to the structural connectivity(morphological unit, slope length, slope steepness, travel time) of a basin and to the funct...Sediment delivery ratio can be used as a measure of sediment connectivity and it can be linked to the structural connectivity(morphological unit, slope length, slope steepness, travel time) of a basin and to the functional connectivity(rainfall-runoff processes at morphological unit scale). In this paper the sediment connectivity approach was applied at basin scale both using Sediment Delivery Distributed(SEDD) model, which takes into account the hillslope sediment transport, and sediment yield measurements carried out at SPA2 experimental basin(Sicily, Italy). The expression of the sediment delivery ratio SDRi of a morphological unit was modified for highlighting two components corresponding to the structural(SDR_(L,i)) and functional(SDR_(F,i)) sediment connectivity, respectively. For SPA2 basin the frequency distribution of the travel time of each morphological unit was used to estimate the coefficient βL of the structural component of the sediment delivery ratio of each morphological unit. Then, using the sediment yield measurements carried out at the outlet of the experimental SPA2 basin in the period April 2000-March 2015, the SEDD model was calibrated at event scale for estimating the coefficient βF of the functional component of the sediment delivery ratio. At event scale the developed analysis stated that the functional connectivity is dependent on the magnitude of erosion events. Intermediate and high events, which were characterized by the lowest values of the functional coefficient, determine a more high functional connectivity and are characterized by a more efficient sediment transport along the hillslopes. Finally, at annual scale, the model was calibrated for the period 2000-2015 and relationships for estimating the coefficient βF,a of the functional component of the sediment delivery ratio taking into account the intensity of erosion events occurring in each year were determined. At annual scale, the analysis demonstrated that the functional coefficient was always greater than the landscape coefficient and the sediment connectivity was always controlled by the low values of the functional component.展开更多
The vegetation restoration project, named the Grain to Green Program, has been operating for more than ten years in the upper reaches of the Beiluo River basin, located in the Loess Plateau of China. It is significant...The vegetation restoration project, named the Grain to Green Program, has been operating for more than ten years in the upper reaches of the Beiluo River basin, located in the Loess Plateau of China. It is significant to be able to estimate the success of preventing soil erosion. In this study, the Revised Universal Soil Loss Equation (RUSLE) and the Sediment Distributed Delivery (SEDD) model were used to assess the annual soil loss derived from water erosion. The results showed that the study area suffered from primary land use changes, with increasing grassland and forest and decreasing farmland from 1990 to 2010. Based on that, the average soil erosion modulus decreased from 18,189.72 t/(km2 a) in 1990– 7408.93 t/(km2 a) in 2000 and 2857.76 t/(km2 a) in 2010. Compared with 1990, the average soil erosion modulus decreased by 59.0% and 84.3% for 2000 and 2010, respectively. Benefiting from the increased vegetation coverage and improved ecological environment, the soil erosion in this study area clearly declined. This research also found that the distribution of the three years of soil erosion was similarly based on topographic factors. The soil erosion modulus varied with different land use types and decreased in the order of residential area>farmland>grassland>forest. The average soil erosion modulus gradually increased with the increase of the slope gradient, and 76.08% of the total soil erosion was concentrated in the region with a gradient more than 15 degrees. The soil erosion modulus also varied with slope aspects in the order of sunny slope>half-sunny slope>half-shady slope>shady slope. This research provides useful reference for soil and water conservation and utilization in this area and offers a technical basis for using the RUSLE to estimate soil erosion in the Loess Plateau of China.展开更多
文摘The modern characterizing techniques, which were used forthe determination of the structure of pharmaceutical substancesand products in this presentation, were small angleX-ray scattering (SAXS), photon correlation spectroscopy (PCS)and transmission electron microscopy (TEM).Different pharmaceutical substances and products such asmodel membranes from fishes, reptiles or carrier systems suchas liposomes, emulsion, and self-emulsifying drug deliverysystems (SEDDs) were characterized in our group by using SAXSfrom a synchrotron source.
文摘As a widely prescribed anti diabetic drug, pioglitazone belongs to class II under BCS and exhibits low and variable oral bioavailability due to its poor aqueous solubility. Its oral absorption is dissolution rate limited, and its solubility and dissolution rate need to be enhanced in order to increase its oral bioavailability. In the present study, we aimed to screen various oils, surfactants and cosolvents. The highest solubility was observed in Labrafac, Tween-80 and propylene glycol. Then the feasibility of formulating pioglitazone SEDDS was evaluated, and the effect of dilution on the dissolution rate and dissolution efficiency of pioglitazone was also analyzed. A comparative evaluation of pioglitazone from SEDDS was made in SGF and 1% SLS. Dissolution of pioglitazone from SEDDS was rapid and higher compared with pure drug. The rate and extent of release of pioglitazone hydrochloride from stable SEDDS （F1） were higher in 1% SLS compared with SGF. The FTIR spectra proved that there was on chemical interaction between excipients and drug. SEM studies confirmed that the size was small and spherical.
文摘Sediment delivery ratio can be used as a measure of sediment connectivity and it can be linked to the structural connectivity(morphological unit, slope length, slope steepness, travel time) of a basin and to the functional connectivity(rainfall-runoff processes at morphological unit scale). In this paper the sediment connectivity approach was applied at basin scale both using Sediment Delivery Distributed(SEDD) model, which takes into account the hillslope sediment transport, and sediment yield measurements carried out at SPA2 experimental basin(Sicily, Italy). The expression of the sediment delivery ratio SDRi of a morphological unit was modified for highlighting two components corresponding to the structural(SDR_(L,i)) and functional(SDR_(F,i)) sediment connectivity, respectively. For SPA2 basin the frequency distribution of the travel time of each morphological unit was used to estimate the coefficient βL of the structural component of the sediment delivery ratio of each morphological unit. Then, using the sediment yield measurements carried out at the outlet of the experimental SPA2 basin in the period April 2000-March 2015, the SEDD model was calibrated at event scale for estimating the coefficient βF of the functional component of the sediment delivery ratio. At event scale the developed analysis stated that the functional connectivity is dependent on the magnitude of erosion events. Intermediate and high events, which were characterized by the lowest values of the functional coefficient, determine a more high functional connectivity and are characterized by a more efficient sediment transport along the hillslopes. Finally, at annual scale, the model was calibrated for the period 2000-2015 and relationships for estimating the coefficient βF,a of the functional component of the sediment delivery ratio taking into account the intensity of erosion events occurring in each year were determined. At annual scale, the analysis demonstrated that the functional coefficient was always greater than the landscape coefficient and the sediment connectivity was always controlled by the low values of the functional component.
基金This study was supported by the National Natural Science Foundation of China(Grant nos.41230852,41440012 and 41101265)Special-Funds of Scientific Research Programs of State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau(A314021403-C2).
文摘The vegetation restoration project, named the Grain to Green Program, has been operating for more than ten years in the upper reaches of the Beiluo River basin, located in the Loess Plateau of China. It is significant to be able to estimate the success of preventing soil erosion. In this study, the Revised Universal Soil Loss Equation (RUSLE) and the Sediment Distributed Delivery (SEDD) model were used to assess the annual soil loss derived from water erosion. The results showed that the study area suffered from primary land use changes, with increasing grassland and forest and decreasing farmland from 1990 to 2010. Based on that, the average soil erosion modulus decreased from 18,189.72 t/(km2 a) in 1990– 7408.93 t/(km2 a) in 2000 and 2857.76 t/(km2 a) in 2010. Compared with 1990, the average soil erosion modulus decreased by 59.0% and 84.3% for 2000 and 2010, respectively. Benefiting from the increased vegetation coverage and improved ecological environment, the soil erosion in this study area clearly declined. This research also found that the distribution of the three years of soil erosion was similarly based on topographic factors. The soil erosion modulus varied with different land use types and decreased in the order of residential area>farmland>grassland>forest. The average soil erosion modulus gradually increased with the increase of the slope gradient, and 76.08% of the total soil erosion was concentrated in the region with a gradient more than 15 degrees. The soil erosion modulus also varied with slope aspects in the order of sunny slope>half-sunny slope>half-shady slope>shady slope. This research provides useful reference for soil and water conservation and utilization in this area and offers a technical basis for using the RUSLE to estimate soil erosion in the Loess Plateau of China.
