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
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
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.
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.
