Spatiotemporal evolution and driving factors of carbon emission efficiency of resource-based cities in the Yellow River Basin of China.

As an important part of regional coordinated development, the high-quality development of the Yellow River Basin has become a national strategy. It is imminent for resource-based cities to perform a high-quality transformation. The analysis of carbon emission efficiency in the Yellow River Basin includes the examination of spatiotemporal evolution characteristics and the main driving factors. This is done by utilizing the super-efficiency SBM-DEA and panel Tobit regression models, with the assistance of night light data. Our findings are as follows: (1) Carbon emissions continue to grow. The "Jiziwan" basin is an area where plenty of high-emitting cities agglomerate. The carbon emission of resource-based cities presents a W-shaped pattern in time. (2) In time, the carbon emission efficiency follows a U-shaped curve. Spatially, the carbon emission efficiency in the middle reaches is comparatively low, whereas it is relatively high in both the upper and lower reaches. And that in high carbon-emitting resource-based cities are in the low to medium range. (3) Carbon emission efficiency has a significant negative relationship with energy intensity, urbanization rate, and population density and a significant positive relationship with industrial proportion. Energy intensity is the most direct driving force. That is to say, we can increase carbon emission efficiency effectively by reducing energy intensity.

[Optimized preparation of ginkgolides A and B long-circulating solid lipid nanoparticles by central composite design and response surface method].

OBJECTIVE: To optimize the formulation of long-circulating solid lipid nanoparticles (LSLN) carrying ginkgolides A and B (GAB) extracted from traditional Chinese medicinal herbs. METHODS: GAB-LSLN was prepared by high pressure homogenization. The effects of such factors as the contents of glycerol monostearate, soybean lecithin and Myrj 59 on the mean diameter, entrapment efficiency and drug loading were investigated using central composite design and response surface method. The data were analyzed using multi-linear equation and second-order polynomial equation for selecting the optimal conditions for LSLN preparation. RESULTS: The method of second-order polynomial equation was superior to multi-linear equation method in view of the multiple correlation coefficients. Under the optimal conditions, the mean diameter, entrapment efficiency, and drug loading of the GAB-LSLN were 169.5 nm, 92.3% and 5.1%, respectively. CONCLUSION: The optimized process for GAB-LSLN preparation is stable, feasible and allows high inclusion rate in the large-scale production of GAB-LSLN.